47 results on '"Vlok, M."'
Search Results
2. The mechanisms of enzymes of the nitrilase superfamily
- Author
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Sewell, B. T., primary, Makumire, S., additional, Venter, G. A., additional, van Heerden, D. P., additional, Dlamini, L., additional, Woodward, J. D., additional, Vlok, M., additional, and Hunter, R., additional
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- 2023
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3. Overexpression of the Small Ubiquitin‐Like Modifier protease OTS1 gene enhances drought tolerance in sugarcane (Saccharum spp. hybrid).
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Masoabi, M., Burger, N. F. V., Botha, A.‐M., Le Roux, M. L., Vlok, M., Snyman, S., and Van der Vyver, C.
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DROUGHT tolerance ,SUGARCANE ,SACCHARUM ,TRANSGENIC plants ,CROPS - Abstract
Sugarcane is an economically important crop plant across the globe as it is the primary source of sugar and biofuel. Its growth and development are greatly influenced by water availability; therefore, in periods of water scarcity, yields are severely compromised. Small Ubiquitin‐Like Modifier (SUMO) proteases play an important role in stress responses by regulating the SUMO‐related post‐translational modification of proteins.In an attempt to enhance drought tolerance in sugarcane, this crop was genetically transformed with a cysteine protease (OVERLY TOLERANT TO SALT‐1; OTS1) from Arabidopsis thaliana using particle bombardment. Transgenic plants were analysed in terms of photosynthetic capacity, oxidative damage, antioxidant accumulation and the SUMO‐enrich protein profile was assessed.Sugarcane transformed with the AtOTS1 gene displayed enhanced drought tolerance and delayed leaf senescence under water deficit compared to the untransformed wild type (WT). The AtOTS1 transgenic plants maintained a high relative moisture content and higher photosynthesis rate when compared to the WT. In addition, when the transgene was expressed at high levels, the transformed plants were able to maintain higher stomatal conductance and chlorophyl content under moderate stress compared to the WT. Under severe water deficit stress, the transgenic plants accumulated less malondialdehyde and maintained membrane integrity. SUMOylation of total protein and protease activity was lower in the AtOTS1 transformed plants compared to the WT, with several SUMO‐enriched proteins exclusively expressed in the transgenics when exposed to water deficit stress.SUMOylation of proteins likely influenced various mechanisms contributing to enhanced drought tolerance in sugarcane. [ABSTRACT FROM AUTHOR]
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- 2023
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4. Comment on Charlier et al., 2019: “The Mandible of Saint-Louis (1270 AD): Retrospective diagnosis and circumstances of death”
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Snoddy, A.M.E., Beaumont, J., Buckley, H.R., Colombo, A., Halcrow, S.E., Kinaston, R.L., and Vlok, M.
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- 2020
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5. Spatiotemporal dynamics of river viruses, bacteria and microeukaryotes
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Judith L. Isaac-Renton, Kirby I. Cronin, Thea Van Rossum, Curtis A. Suttle, Matthew A. Croxen, Vlok M, Natalie Prystajecky, Tian A, Michael A. Peabody, Miguel I. Uyaguari-Diaz, Patrick Tang, Fiona S. L. Brinkman, William W. L. Hsiao, and Michael Chan
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Environmental change ,Microbial population biology ,Ecology ,Metagenomics ,Microorganism ,Context (language use) ,Ecosystem ,Human virome ,Microbiome ,Biology - Abstract
Freshwater is an essential resource of increasing value, as clean water sources diminish. Microorganisms in rivers, a major source of renewable freshwater, are significant due to their role in drinking water safety, signalling environmental contamination1, and driving global nutrient cycles2,3. However, a foundational understanding of microbial communities in rivers is lacking4, especially temporally and for viruses5‒7. No studies to date have examined the composition of the free-floating river virome over time, and explanations of the underlying causes of spatial and temporal changes in riverine microbial composition, especially for viruses, remain unexplored. Here, we report relationships among riverine microbial communities and their environment across time, space, and superkingdoms (viruses, bacteria, and microeukaryotes), using metagenomics and marker-based microbiome analysis methods. We found that many superkingdom pairs were synchronous and had consistent shifts with sudden environmental change. However, synchrony strength, and relationships with environmental conditions, varied across space and superkingdoms. Variable relationships were observed with seasonal indicators and chemical conditions previously found to be predictive of bacterial community composition4,8‒10, emphasizing the complexity of riverine ecosystems and raising questions around the generalisability of single-site and bacteria-only studies. In this first study of riverine viromes over time, DNA viral communities were stably distinct between sites, suggesting the similarity in riverine bacteria across significant geographic distances10‒12does not extend to viruses, and synchrony was surprisingly observed between DNA and RNA viromes. This work provides foundational data for riverine microbial dynamics in the context of environmental and chemical conditions and illustrates how a bacteria-only or single-site approach would lead to an incorrect description of microbial dynamics. We show how more holistic microbial community analysis, including viruses, is necessary to gain a more accurate and deeper understanding of microbial community dynamics.
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- 2018
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6. Rehabilitation of the Hillendale Mine’s residue storage facility
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Beukes, Jan, primary, Vlok, M, additional, and Khosa, Fumani, additional
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- 2019
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7. A New Application of the Bioarchaeology of Care Approach: A Case Study from the Metal Period, the Philippines
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Vlok, M., primary, Paz, V., additional, Crozier, R., additional, and Oxenham, M., additional
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- 2017
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8. Post fire indicators of fire intensity at indigenous forest margins in the southern Cape, South Africa
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Schmidt, A. G., primary and Vlok, M., additional
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- 2002
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9. Protocol for unified metabolomics and proteomics analysis of formalin-fixed paraffin-embedded tissue.
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Isaiah AR, Luies L, Loots DT, Williams AA, Vlok M, Chegou NN, Tutu van Furth M, van der Kuip M, and Mason S
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The use of archival formalin-fixed paraffin-embedded (FFPE) tissue samples for biochemical analyses is problematic because of the formation of a Schiff base, leading to low protein and metabolite yields during analytical extractions. Here, we overcome this issue using a unified protocol on FFPE tissue for metabolomics and proteomics analyses. Using 20 mg of wet mass tissue, this protocol consistently extracted more than 50 metabolites (across 11 classes of metabolites) and over 900 proteins., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2024
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10. High prevalence of adult and nonadult scurvy in an early agricultural transition site from Mainland Southeast Asia was associated with decreased survivorship.
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Vlok M, Oxenham M, Domett K, Trinh HH, Minh TT, Nguyen MH, Matsumura H, and Buckley H
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- Humans, Adult, Male, Prevalence, Middle Aged, Female, Vietnam epidemiology, Young Adult, History, Ancient, Adolescent, Child, Survivorship, Child, Preschool, Aged, Infant, Scurvy epidemiology
- Abstract
Objectives: The osteological paradox recognizes that the presence of lesions is not always directly related with increased mortality. When combined with the clinical, historical, and epidemiological literature on scurvy, survivorship analysis, a form of statistical analysis to assess the relationship between the presence of diseases in the archeological record and survival, helps determine the overall burden of the disease both in terms of morbidity and mortality. This article explores the relationship between scurvy and survivorship in 26 adults from Man Bac, a Neolithic site from northern Vietnam together with prepublished evidence of scurvy in the nonadult population (n = 44)., Methods: Diagnosis of scurvy included differential diagnosis combined with the Snoddy, A. M. E., Buckley, H. R., Elliott, G. E., Standen, V. G., Arriaza, B. T., & Halcrow, S. E. (2018). Macroscopic features of scurvy in human skeletal remains: A literature synthesis and diagnostic guide. American Journal of Physical Anthropology, 167(4), 876-895. https://doi.org/10.1002/ajpa.23699 threshold criteria and the Brickley, M. B., & Morgan, B. (2023). Assessing diagnostic certainty for scurvy and rickets in human skeletal remains. American Journal of Biological Anthropology, 181, 637-645 diagnostic certainty approaches. Kaplan-Meier survival curves were produced to assess the relationship between the presence of probable scurvy and age-at-death., Results: The prevalence of probable scurvy in adults (35%) was considerably lower than reported for the nonadults (80%). Almost all lesions observed in the adults were in a mixed stage of healing. Kaplan-Meier analysis demonstrated no difference in survivorship between infants and children (<15 years) with or without probable scurvy, whereas a meaningful difference was observed for the adults and adolescents (15+ years)., Conclusions: The findings demonstrate that scurvy considerably decreased survivorship to older age categories. The degree of lesion remodeling, however, indicates that scurvy was not necessarily the direct cause of death but contributed to an overall disease burden that was ultimately fatal., (© 2024 The Author(s). American Journal of Biological Anthropology published by Wiley Periodicals LLC.)
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- 2024
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11. Identification of the proteolytic signature in CVB3-infected cells.
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Vlok M, Solis N, Sadasivan J, Mohamud Y, Warsaba R, Kizhakkedathu J, Luo H, Overall CM, and Jan E
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- Humans, Mice, Animals, HeLa Cells, Viral Proteins metabolism, Proteomics methods, Host-Pathogen Interactions, 3C Viral Proteases metabolism, Cell Line, Viral Proteases metabolism, Polyproteins metabolism, Enterovirus B, Human metabolism, Proteolysis, Coxsackievirus Infections virology, Coxsackievirus Infections metabolism
- Abstract
Coxsackievirus B3 (CVB3) encodes proteinases that are essential for processing of the translated viral polyprotein. Viral proteinases also target host proteins to manipulate cellular processes and evade innate antiviral responses to promote replication and infection. While some host protein substrates of the CVB3 3C and 2A cysteine proteinases have been identified, the full repertoire of targets is not known. Here, we utilize an unbiased quantitative proteomics-based approach termed terminal amine isotopic labeling of substrates (TAILS) to conduct a global analysis of CVB3 protease-generated N-terminal peptides in both human HeLa and mouse cardiomyocyte (HL-1) cell lines infected with CVB3. We identified >800 proteins that are cleaved in CVB3-infected HeLa and HL-1 cells including the viral polyprotein, known substrates of viral 3C proteinase such as PABP, DDX58, and HNRNPs M, K, and D and novel cellular proteins. Network and GO-term analysis showed an enrichment in biological processes including immune response and activation, RNA processing, and lipid metabolism. We validated a subset of candidate substrates that are cleaved under CVB3 infection and some are direct targets of 3C proteinase in vitro . Moreover, depletion of a subset of TAILS-identified target proteins decreased viral yield. Characterization of two target proteins showed that expression of 3C
pro -targeted cleaved fragments of emerin and aminoacyl-tRNA synthetase complex-interacting multifunctional protein 2 modulated autophagy and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway, respectively. The comprehensive identification of host proteins targeted during virus infection provides insights into the cellular pathways manipulated to facilitate infection., Importance: RNA viruses encode proteases that are responsible for processing viral proteins into their mature form. Viral proteases also target and cleave host cellular proteins; however, the full catalog of these target proteins is incomplete. We use a technique called terminal amine isotopic labeling of substrates (TAILS), an N-terminomics to identify host proteins that are cleaved under virus infection. We identify hundreds of cellular proteins that are cleaved under infection, some of which are targeted directly by viral protease. Revealing these target proteins provides insights into the host cellular pathways and antiviral signaling factors that are modulated to promote virus infection and potentially leading to virus-induced pathogenesis., Competing Interests: The authors declare no conflict of interest.- Published
- 2024
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12. Data-independent LC-MS/MS analysis of ME/CFS plasma reveals a dysregulated coagulation system, endothelial dysfunction, downregulation of complement machinery.
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Nunes M, Vlok M, Proal A, Kell DB, and Pretorius E
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- Humans, Male, Female, Middle Aged, Adult, Chromatography, Liquid, Case-Control Studies, Proteomics, COVID-19 blood, Complement System Proteins metabolism, Endothelium, Vascular metabolism, Endothelium, Vascular physiopathology, Liquid Chromatography-Mass Spectrometry, Tandem Mass Spectrometry, Blood Coagulation, Biomarkers blood, Down-Regulation, Fatigue Syndrome, Chronic blood, Fatigue Syndrome, Chronic physiopathology, Fatigue Syndrome, Chronic immunology, Fatigue Syndrome, Chronic metabolism
- Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic condition that is characterized by unresolved fatigue, post-exertion symptom exacerbation (PESE), cognitive dysfunction, orthostatic intolerance, and other symptoms. ME/CFS lacks established clinical biomarkers and requires further elucidation of disease mechanisms. A growing number of studies demonstrate signs of hematological and cardiovascular pathology in ME/CFS cohorts, including hyperactivated platelets, endothelial dysfunction, vascular dysregulation, and anomalous clotting processes. To build on these findings, and to identify potential biomarkers that can be related to pathophysiology, we measured differences in protein expression in platelet-poor plasma (PPP) samples from 15 ME/CFS study participants and 10 controls not previously infected with SARS-CoV-2, using DIA LC-MS/MS. We identified 24 proteins that are significantly increased in the ME/CFS group compared to the controls, and 21 proteins that are significantly downregulated. Proteins related to clotting processes - thrombospondin-1 (important in platelet activation), platelet factor 4, and protein S - were differentially expressed in the ME/CFS group, suggestive of a dysregulated coagulation system and abnormal endothelial function. Complement machinery was also significantly downregulated, including C9 which forms part of the membrane attack complex. Additionally, we identified a significant upregulation of lactotransferrin, protein S100-A9, and an immunoglobulin variant. The findings from this experiment further implicate the coagulation and immune system in ME/CFS, and bring to attention the pathology of or imposed on the endothelium. This study highlights potential systems and proteins that require further research with regards to their contribution to the pathogenesis of ME/CFS, symptom manifestation, and biomarker potential, and also gives insight into the hematological and cardiovascular risk for ME/CFS individuals affected by diabetes mellitus., (© 2024. The Author(s).)
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- 2024
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13. Corrigendum to "Technical note: The use and misuse of threshold diagnostic criteria in paleopathology".
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Vlok M
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- 2024
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14. Cleavage of 14-3-3ε by the enteroviral 3C protease dampens RIG-I-mediated antiviral signaling.
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Andrews DDT, Vlok M, Akbari Bani D, Hay BN, Mohamud Y, Foster LJ, Luo H, Overall CM, and Jan E
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- Animals, Cysteine Endopeptidases metabolism, DEAD Box Protein 58 metabolism, Immunity, Innate, Mammals, Peptide Hydrolases metabolism, Signal Transduction, Tretinoin, Viral Proteins metabolism, 3C Viral Proteases, Picornaviridae metabolism, Picornaviridae Infections immunology, Picornaviridae Infections virology
- Abstract
Viruses have evolved diverse strategies to evade the host innate immune response and promote infection. The retinoic acid-inducible gene I (RIG-I)-like receptors RIG-I and MDA5 are antiviral factors that sense viral RNA and trigger downstream signal via mitochondrial antiviral-signaling protein (MAVS) to activate type I interferon expression. 14-3-3ε is a key component of the RIG-I translocon complex that interacts with MAVS at the mitochondrial membrane; however, the exact role of 14-3-3ε in this pathway is not well understood. In this study, we demonstrate that 14-3-3ε is a direct substrate of both the poliovirus and coxsackievirus B3 (CVB3) 3C proteases (3C
pro ) and that it is cleaved at Q236↓G237, resulting in the generation of N- and C-terminal fragments of 27.0 and 2.1 kDa, respectively. While the exogenous expression of wild-type 14-3-3ε enhances IFNB mRNA production during poly(I:C) stimulation, expression of the truncated N-terminal fragment does not. The N-terminal 14-3-3ε fragment does not interact with RIG-I in co-immunoprecipitation assays, nor can it facilitate RIG-I translocation to the mitochondria. Probing the intrinsically disordered C-terminal region identifies key residues responsible for the interaction between 14-3-3ε and RIG-I. Finally, overexpression of the N-terminal fragment promotes CVB3 infection in mammalian cells. The strategic enterovirus 3Cpro -mediated cleavage of 14-3-3ε antagonizes RIG-I signaling by disrupting critical interactions within the RIG-I translocon complex, thus contributing to evasion of the host antiviral response. IMPORTANCE Host antiviral factors work to sense virus infection through various mechanisms, including a complex signaling pathway known as the retinoic acid-inducible gene I (RIG-I)-like receptor pathway. This pathway drives the production of antiviral molecules known as interferons, which are necessary to establish an antiviral state in the cellular environment. Key to this antiviral signaling pathway is the small chaperone protein 14-3-3ε, which facilitates the delivery of a viral sensor protein, RIG-I, to the mitochondria. In this study, we show that the enteroviral 3C protease cleaves 14-3-3ε during infection, rendering it incapable of facilitating this antiviral response. We also find that the resulting N-terminal cleavage fragment dampens RIG-I signaling and promotes virus infection. Our findings reveal a novel viral strategy that restricts the antiviral host response and provides insights into the mechanisms underlying 14-3-3ε function in RIG-I antiviral signaling., Competing Interests: The authors declare no conflict of interest.- Published
- 2023
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15. 'A long want': an archival exploration of scurvy in the Otago goldfields of New Zealand.
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Buckley HR, Vlok M, Petchey P, and Ritchie N
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In this paper we test a long-held assumption regarding Otago, New Zealand, goldfields life and death- that scurvy was a ubiquitous and persistent cause of misery and death among the goldminers. We will also explore a parallel argument that the Chinese market gardeners played a large role in stamping out the disease in the goldfields. Through the interrogation of various archival medical primary sources, we show that scurvy was indeed a terrible scourge in the Otago goldfields, but only during the initial rushes into new regions. We also argue that while Chinese market gardeners undoubtedly contributed to a more nutritious and varied diet for European miners and settlers, scurvy had already markedly reduced in frequency by the time of their arrival in the gold fields. Patient-oriented accounts of scurvy in the gold demonstrate the clinical and functional cost of scurvy in during the initial gold rushes of Otago. Furthermore, individual stories of previously anonymous patients found locked in these archival sources demonstrate the importance of re-humanising the past to understand the biological and social context of these frontier times., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)
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- 2023
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16. Paleoepidemiology of cribra orbitalia: Insights from early seventh millennium BP Con Co Ngua, Vietnam.
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Wang T, McFadden C, Buckley H, Domett K, Willis A, Trinh HH, Matsumura H, Vlok M, and Oxenham MF
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- Male, Female, Humans, Vietnam epidemiology, Orbit pathology, Anemia, Iron-Deficiency pathology
- Abstract
Objectives: We test the hypothesis that the condition(s) leading to the development of cribra orbitalia at Con Co Ngua, an early seventh millennium sedentary foraging community in Vietnam, effectively reduced the resilience of the population to subsequent health/disease impacts. An assessment of both the implications and potential etiology of cribra orbitalia in this specific population is carried out., Methods: The effective sample included 141 adults aged ≥15 years (53 females, 71 males, and 17 unknown sex) and 15 pre-adults aged ≤14 years. Cribra orbitalia was identified by way of cortical bone porosity of the orbital roof initiated within the diplöic space, rather than initiated subperiosteally. The approach is also robust to the misidentification of various pseudo-lesions. Resultant data was analyzed using Kaplan-Meier survival analysis., Results: Median survival is higher in adults aged ≥15 years without cribra orbitalia than those with this lesion. For the pre-adult cohort, the opposite pattern is seen where median survival is higher in those with cribra orbitalia than those without., Conclusion: Adults displayed increased frailty and pre-adults increased resilience with respect to cribra orbitalia. The differential diagnosis for a survival analysis of adults and pre-adults with and without cribra orbitalia included iron deficiency anemia and B12/folate deficiency, parasitism (including hydatid disease and malaria) in addition to thalassemia. The most parsimonious explanation for observed results is for both thalassemia and malaria being the chief etiological agents, while appreciating these conditions interact with, and can cause, other forms such as hematinic deficiency anemias., (© 2023 The Authors. American Journal of Biological Anthropology published by Wiley Periodicals LLC.)
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- 2023
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17. Technical note: The use and misuse of threshold diagnostic criteria in paleopathology.
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Vlok M
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- Humans, Paleopathology, Rickets, Vitamin D Deficiency diagnosis, Scurvy diagnosis, Ascorbic Acid Deficiency
- Abstract
Weighted threshold diagnostic criteria approaches have emerged for diseases that involve skeletal/bony tissue that are readily diagnosed in the field of paleopathology such as Vitamin C deficiency (scurvy), Vitamin D deficiency (rickets) and treponemal disease. These criteria differ from traditional differential diagnosis in that they involve standardized inclusion criteria based on the lesion's specificity to the disease. Here I discuss the limitations and benefits of threshold criteria. I argue that while these criteria will benefit from further revision such as inclusion of lesion severity, and the incorporation of exclusion criteria, threshold diagnostic approaches have considerable value in the future of diagnosis in the field., (© 2023 The Author. American Journal of Biological Anthropology published by Wiley Periodicals LLC.)
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- 2023
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18. Reply to Mays and Brickley, 2023 "Dietary calcium versus vitamin D in rickets: A response to Vlok et al."
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Snoddy AME, Vlok M, Wheeler BJ, Ramesh N, Standen VG, and Arriaza BT
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- Humans, Vitamin D, Calcium, Dietary, Vitamins, Rickets etiology, Vitamin D Deficiency
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- 2023
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19. Human femur morphology and histology variation with ancestry and behaviour in an ancient sample from Vietnam.
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Walker MM, Oxenham MF, Vlok M, Matsumura H, Thi Mai Huong N, Trinh HH, Minh TT, and Miszkiewicz JJ
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- Humans, Vietnam, Haversian System anatomy & histology, Histological Techniques, Femur anatomy & histology, Lower Extremity
- Abstract
Background: There is a genetic component to the minimum effective strain (MES)-a threshold which determines when bone will adapt to function-which suggests ancestry should play a role in bone (re)modelling. Further elucidating this is difficult in living human populations because of the high global genetic admixture. We examined femora from an anthropological skeletal assemblage (Mán Bạc, Vietnam) representing distinct ancestral groups. We tested whether femur morphological and histological markers of modelling and remodelling differed between ancestries despite their similar lifestyles., Methods: Static histomorphometry data collected from subperiosteal cortical bone of the femoral midshaft, and gross morphometric measures of femur robusticity, were studied in 17 individuals from the Mán Bạc collection dated to 1906-1523 cal. BC. This assemblage represents agricultural migrants with affinity to East Asian groups, who integrated with the local hunter-gatherers with affinity to Australo-Papuan groups during the mid-Holocene. Femur robusticity and histology data were compared between groups of 'Migrant' (n = 8), 'Admixed' (n = 4), and 'Local' (n = 5)., Results: Local individuals had more robust femoral diaphyses with greater secondary osteon densities, and relatively large secondary osteon and Haversian canal parameters than the migrants. The Migrant group showed gracile femoral shafts with the least dense bone made up of small secondary osteons and Haversian canals. The Admixed individuals fell between the Migrant and Local categories in terms of their femoral data. However, we also found that measures of how densely bone is remodelled per unit area were in a tight range across all three ancestries., Conclusions: Bone modelling and remodelling markers varied with ancestral histories in our sample. This suggests that there is an ancestry related predisposition to bone optimising its metabolic expenditure likely in relation to the MES. Our results stress the need to incorporate population genetic history into hierarchical bone analyses. Understanding ancestry effects on bone morphology has implications for interpreting biomechanical loading history in past and modern human populations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier GmbH. All rights reserved.)
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- 2023
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20. Reply to: Common orthopaedic trauma may explain 31,000-year-old remains.
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Vlok M, Maloney T, Dilkes-Hall IE, Oktaviana AA, Setiawan P, Priyatno AAD, Ririmasse M, Geria IM, Effendy MAR, Istiawan B, Atmoko FT, Adhityatama S, Moffat I, Joannes-Boyau R, Brumm A, and Aubert M
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- Humans, Infant, Newborn, Orthopedics, Fractures, Bone epidemiology
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- 2023
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21. The role of dietary calcium in the etiology of childhood rickets in the past and the present.
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Vlok M, Snoddy AME, Ramesh N, Wheeler BJ, Standen VG, and Arriaza BT
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- Infant, Humans, Calcium, Dietary, Calcium, Vitamin D, Vitamins, Rickets etiology, Rickets drug therapy, Vitamin D Deficiency complications
- Abstract
For more than two centuries, lack of sunlight has been understood to cause vitamin D deficiency and documented as a primary cause of rickets. As such, evidence of rickets in the archeological record has been used as a proxy for vitamin D status in past individuals and populations. In the last decade, a clinical global consensus has emerged wherein it is recognized that dietary calcium deficiency also plays a role in the manifestation of rickets and classic skeletal deformities may not form if dietary calcium is normal even if vitamin D is deficient. This disease is now clinically called "nutritional rickets" to reflect the fact that rickets can take calcium deficiency-predominant or vitamin D deficiency-predominant forms. However, there are currently no paleopathological studies wherein dietary calcium deficiency is critically considered a primary etiology of the disease. We review here the interplay of calcium, vitamin D, and phosphorous in bone homeostasis, examine the role of dietary calcium in human health, and critically explore the clinical literature on calcium deficiency-predominant rickets. Finally, we report a case of rickets from the late Formative Period (~2500-1500 years ago) of the Atacama Desert and argue the disease in this infant is likely an example of calcium deficiency-predominant rickets. We conclude that most archeological cases of rickets are the result of multiple micronutrient deficiencies that compound to manifest in macroscopic skeletal lesions. For clinicians, these factors are important for implementing best treatment practice, and for paleopathologists they are necessary for appropriate interpretation of health in past communities., (© 2022 The Authors. American Journal of Human Biology published by Wiley Periodicals LLC.)
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- 2023
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22. Climate change, human health, and resilience in the Holocene.
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Robbins Schug G, Buikstra JE, DeWitte SN, Baker BJ, Berger E, Buzon MR, Davies-Barrett AM, Goldstein L, Grauer AL, Gregoricka LA, Halcrow SE, Knudson KJ, Larsen CS, Martin DL, Nystrom KC, Perry MA, Roberts CA, Santos AL, Stojanowski CM, Suby JA, Temple DH, Tung TA, Vlok M, Watson-Glen T, and Zakrzewski SR
- Subjects
- Humans, Climate Change, Sustainable Development, Probability, Carcinoma, Renal Cell, Kidney Neoplasms
- Abstract
Climate change is an indisputable threat to human health, especially for societies already confronted with rising social inequality, political and economic uncertainty, and a cascade of concurrent environmental challenges. Archaeological data about past climate and environment provide an important source of evidence about the potential challenges humans face and the long-term outcomes of alternative short-term adaptive strategies. Evidence from well-dated archaeological human skeletons and mummified remains speaks directly to patterns of human health over time through changing circumstances. Here, we describe variation in human epidemiological patterns in the context of past rapid climate change (RCC) events and other periods of past environmental change. Case studies confirm that human communities responded to environmental changes in diverse ways depending on historical, sociocultural, and biological contingencies. Certain factors, such as social inequality and disproportionate access to resources in large, complex societies may influence the probability of major sociopolitical disruptions and reorganizations-commonly known as "collapse." This survey of Holocene human-environmental relations demonstrates how flexibility, variation, and maintenance of Indigenous knowledge can be mitigating factors in the face of environmental challenges. Although contemporary climate change is more rapid and of greater magnitude than the RCC events and other environmental changes we discuss here, these lessons from the past provide clarity about potential priorities for equitable, sustainable development and the constraints of modernity we must address.
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- 2023
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23. Targeting Nup358/RanBP2 by a viral protein disrupts stress granule formation.
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Sadasivan J, Vlok M, Wang X, Nayak A, Andino R, and Jan E
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- Animals, Stress Granules, Cell Line, Drosophila, Cytoplasmic Granules metabolism, Viral Proteins metabolism, Virus Replication
- Abstract
Viruses have evolved mechanisms to modulate cellular pathways to facilitate infection. One such pathway is the formation of stress granules (SG), which are ribonucleoprotein complexes that assemble during translation inhibition following cellular stress. Inhibition of SG assembly has been observed under numerous virus infections across species, suggesting a conserved fundamental viral strategy. However, the significance of SG modulation during virus infection is not fully understood. The 1A protein encoded by the model dicistrovirus, Cricket paralysis virus (CrPV), is a multifunctional protein that can bind to and degrade Ago-2 in an E3 ubiquitin ligase-dependent manner to block the antiviral RNA interference pathway and inhibit SG formation. Moreover, the R146 residue of 1A is necessary for SG inhibition and CrPV infection in both Drosophila S2 cells and adult flies. Here, we uncoupled CrPV-1A's functions and provide insight into its underlying mechanism for SG inhibition. CrPV-1A mediated inhibition of SGs requires the E3 ubiquitin-ligase binding domain and the R146 residue, but not the Ago-2 binding domain. Wild-type but not mutant CrPV-1A R146A localizes to the nuclear membrane which correlates with nuclear enrichment of poly(A)+ RNA. Transcriptome changes in CrPV-infected cells are dependent on the R146 residue. Finally, Nup358/RanBP2 is targeted and degraded in CrPV-infected cells in an R146-dependent manner and the depletion of Nup358 blocks SG formation. We propose that CrPV utilizes a multiprong strategy whereby the CrPV-1A protein interferes with a nuclear event that contributes to SG inhibition in order to promote infection., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Sadasivan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2022
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24. Proteomics analysis of the p.G849D variant in neurexin 2 alpha may reveal insight into Parkinson's disease pathobiology.
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Cuttler K, Fortuin S, Müller-Nedebock AC, Vlok M, Cloete R, and Bardien S
- Abstract
Parkinson's disease (PD), the fastest-growing neurological disorder globally, has a complex etiology. A previous study by our group identified the p.G849D variant in neurexin 2 ( NRXN2 ), encoding the synaptic protein, NRXN2α, as a possible causal variant of PD. Therefore, we aimed to perform functional studies using proteomics in an attempt to understand the biological pathways affected by the variant. We hypothesized that this may reveal insight into the pathobiology of PD. Wild-type and mutant NRXN2α plasmids were transfected into SH-SY5Y cells. Thereafter, total protein was extracted and prepared for mass spectrometry using a Thermo Scientific Fusion mass spectrometer equipped with a Nanospray Flex ionization source. The data were then interrogated against the UniProt H. sapiens database and afterward, pathway and enrichment analyses were performed using in silico tools. Overexpression of the wild-type protein led to the enrichment of proteins involved in neurodegenerative diseases, while overexpression of the mutant protein led to the decline of proteins involved in ribosomal functioning. Thus, we concluded that the wild-type NRXN2α may be involved in pathways related to the development of neurodegenerative disorders, and that biological processes related to the ribosome, transcription, and tRNA, specifically at the synapse, could be an important mechanism in PD. Future studies targeting translation at the synapse in PD could therefore provide further information on the pathobiology of the disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Cuttler, Fortuin, Müller-Nedebock, Vlok, Cloete and Bardien.)
- Published
- 2022
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25. Proteomics of fibrin amyloid microclots in long COVID/post-acute sequelae of COVID-19 (PASC) shows many entrapped pro-inflammatory molecules that may also contribute to a failed fibrinolytic system.
- Author
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Kruger A, Vlok M, Turner S, Venter C, Laubscher GJ, Kell DB, and Pretorius E
- Subjects
- Biomarkers, C-Reactive Protein metabolism, Fibrin metabolism, Fibrinogen metabolism, Humans, Interleukin-6, Plasma Kallikrein, Platelet Factor 4, Proteomics, alpha-2-Antiplasmin, von Willebrand Factor analysis, Post-Acute COVID-19 Syndrome, COVID-19 complications, Diabetes Mellitus, Type 2 complications, Thrombosis diagnosis
- Abstract
Background: Post-acute sequelae of COVID-19 (PASC), also now known as long COVID, has become a major global health and economic burden. Previously, we provided evidence that there is a significant insoluble fibrin amyloid microclot load in the circulation of individuals with long COVID, and that these microclots entrap a substantial number of inflammatory molecules, including those that might prevent clot breakdown. Scientifically, the most challenging aspect of this debilitating condition is that traditional pathology tests such as a serum CRP (C-reactive protein) may not show any significant abnormal inflammatory markers, albeit these tests measure only the soluble inflammatory molecules. Elevated, or abnormal soluble biomarkers such as IL-6, D-Dimer or fibrinogen indicate an increased risk for thrombosis or a host immune response in COVID-19. The absence of biomarkers in standard pathology tests, result in a significant amount of confusion for patients and clinicians, as patients are extremely sick or even bed-ridden but with no regular identifiable reason for their disease. Biomarkers that are currently available cannot detect the molecules present in the microclots we identified and are therefore unable to confirm their presence or the mechanisms that drive their formation., Methods: Here we analysed the protein content of double-digested microclots of 99 long COVID patients and 29 healthy controls. The patients suffering from long COVID reported their symptoms through a questionnaire completed by themselves or their attending physician., Results: Our long COVID cohort's symptoms were found to be in line with global findings, where the most prevalent symptoms were constant fatigue (74%,) cognitive impairment (71%) and depression and anxiety (30%). Our most noteworthy findings were a reduced level of plasma Kallikrein compared to our controls, an increased level of platelet factor 4 (PF4) von Willebrand factor (VWF), and a marginally increased level of α-2 antiplasmin (α-2-AP). We also found a significant presence of antibodies entrapped inside these microclots., Conclusion: Our results confirm the presence of pro-inflammatory molecules that may also contribute to a failed fibrinolysis phenomenon, which could possibly explain why individuals with long COVID suffer from chronic fatigue, dyspnoea, or cognitive impairment. In addition, significant platelet hyperactivation was noted. Hyperactivation will result in the granular content of platelets being shed into the circulation, including PF4. Overall, our results provide further evidence of both a failed fibrinolytic system in long COVID/PASC and the entrapment of many proteins whose presence might otherwise go unrecorded. These findings might have significant implications for individuals with pre-existing comorbidities, including cardiovascular disease and type 2 diabetes., (© 2022. The Author(s).)
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- 2022
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26. Surgical amputation of a limb 31,000 years ago in Borneo.
- Author
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Maloney TR, Dilkes-Hall IE, Vlok M, Oktaviana AA, Setiawan P, Priyatno AAD, Ririmasse M, Geria IM, Effendy MAR, Istiawan B, Atmoko FT, Adhityatama S, Moffat I, Joannes-Boyau R, Brumm A, and Aubert M
- Subjects
- Borneo, Calcium Carbonate, Caves, Child, History, Ancient, Humans, Amputation, Surgical history, Body Remains
- Abstract
The prevailing view regarding the evolution of medicine is that the emergence of settled agricultural societies around 10,000 years ago (the Neolithic Revolution) gave rise to a host of health problems that had previously been unknown among non-sedentary foraging populations, stimulating the first major innovations in prehistoric medical practices
1,2 . Such changes included the development of more advanced surgical procedures, with the oldest known indication of an 'operation' formerly thought to have consisted of the skeletal remains of a European Neolithic farmer (found in Buthiers-Boulancourt, France) whose left forearm had been surgically removed and then partially healed3 . Dating to around 7,000 years ago, this accepted case of amputation would have required comprehensive knowledge of human anatomy and considerable technical skill, and has thus been viewed as the earliest evidence of a complex medical act3 . Here, however, we report the discovery of skeletal remains of a young individual from Borneo who had the distal third of their left lower leg surgically amputated, probably as a child, at least 31,000 years ago. The individual survived the procedure and lived for another 6-9 years, before their remains were intentionally buried in Liang Tebo cave, which is located in East Kalimantan, Indonesian Borneo, in a limestone karst area that contains some of the world's earliest dated rock art4 . This unexpectedly early evidence of a successful limb amputation suggests that at least some modern human foraging groups in tropical Asia had developed sophisticated medical knowledge and skills long before the Neolithic farming transition., (© 2022. The Author(s).)- Published
- 2022
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27. Photodynamic and Contact Killing Polymeric Fabric Coating for Bacteria and SARS-CoV-2.
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Wright T, Vlok M, Shapira T, Olmstead AD, Jean F, and Wolf MO
- Subjects
- Anti-Infective Agents chemistry, COVID-19 prevention & control, COVID-19 virology, Coated Materials, Biocompatible pharmacology, Escherichia coli drug effects, Humans, Methicillin-Resistant Staphylococcus aureus drug effects, Photochemotherapy methods, Reactive Oxygen Species metabolism, SARS-CoV-2 isolation & purification, Textiles toxicity, Ultraviolet Rays, Anti-Infective Agents pharmacology, Bacteria drug effects, Coated Materials, Biocompatible chemistry, Polymers chemistry, SARS-CoV-2 drug effects, Textiles analysis
- Abstract
The development of low-cost, non-toxic, scalable antimicrobial textiles is needed to address the spread of deadly pathogens. Here, we report a polysiloxane textile coating that possesses two modes of antimicrobial inactivation, passive contact inactivation through amine/imine functionalities and active photodynamic inactivation through the generation of reactive oxygen species (ROS). This material can be coated and cross-linked onto natural and synthetic textiles through a simple soak procedure, followed by UV cure to afford materials exhibiting no aqueous leaching and only minimal leaching in organic solvents. This coating minimally impacts the mechanical properties of the fabric while also imparting hydrophobicity. Passive inactivation of Escherichia coli ( E. coli ) and methicillin-resistant Staphylococcus aureus (MRSA) is achieved with >98% inactivation after 24 h, with a 23× and 3× inactivation rate increase against E. coli and MRSA, respectively, when green light is used to generate ROS. Up to 90% decrease in the infectivity of SARS-CoV-2 after 2 h of irradiated incubation with the material is demonstrated. These results show that modifying textiles with dual-functional polymers results in robust and highly antimicrobial materials that are expected to find widespread use in combating the spread of deadly pathogens.
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- 2022
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28. Hydatid disease (Echinococcosis granulosis) diagnosis from skeletal osteolytic lesions in an early seventh-millennium BP forager community from preagricultural northern Vietnam.
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Vlok M, Buckley HR, Domett K, Willis A, Tromp M, Trinh HH, Minh TT, Mai Huong NT, Nguyen LC, Matsumura H, Huu NT, and Oxenham MF
- Subjects
- Humans, Animals, Vietnam epidemiology, Radiography, Deer, Echinococcosis diagnosis, Echinococcus, Cysts, Canidae
- Abstract
Objectives: Con Co Ngua is a complex, sedentary forager site from northern Vietnam dating to the early seventh millennium BP. Prior research identified a calcified Echinococcus granulosis cyst, which causes hydatid disease. Osteolytic lesions consistent with hydatid disease were also present in this individual and others. Hydatid disease is observed in high frequencies in pastoralists, and its presence in a hunter-gatherer community raises questions regarding human-animal interaction prior to farming. The objective of this article is to identify and describe the epidemiology of hydatid disease in the human skeletal assemblage at Con Co Ngua., Materials and Methods: One hundred and fifty-five individuals were macroscopically assessed for lesions. Of these, eight individuals were radiographed. Hydatid disease was diagnosed using a new threshold criteria protocol derived from clinical literature, which prioritizes lesions specific to the parasite., Results: Twenty-two individuals (14.2%) presented with osteolytic lesions consistent with hydatid disease, affecting the distal humerus, proximal femur and forearm, and pelvis. Seven individuals radiographed (4.5%) had multilocular cystic lesions strongly diagnostic for hydatid disease. All probable cases had lesions of the distal humerus. The remaining lesions were macroscopically identical to those radiographed and were considered possible cases., Discussion: While hydatid disease has previously been found in pre-agricultural communities, the high prevalence at Con Co Ngua is non-incidental. We propose that the presence of wild canids and management of wild buffalo and deer increased the risk of disease transmission. These findings further reveal subsistence complexity among hunter-gatherers living millennia prior to the adoption of farming in Southeast Asia., (© 2021 Wiley Periodicals LLC.)
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- 2022
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29. Mechanistic insights into COVID-19 by global analysis of the SARS-CoV-2 3CL pro substrate degradome.
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Pablos I, Machado Y, de Jesus HCR, Mohamud Y, Kappelhoff R, Lindskog C, Vlok M, Bell PA, Butler GS, Grin PM, Cao QT, Nguyen JP, Solis N, Abbina S, Rut W, Vederas JC, Szekely L, Szakos A, Drag M, Kizhakkedathu JN, Mossman K, Hirota JA, Jan E, Luo H, Banerjee A, and Overall CM
- Subjects
- Humans, Substrate Specificity, COVID-19, Coronavirus 3C Proteases metabolism, SARS-CoV-2 metabolism
- Abstract
The main viral protease (3CL
pro ) is indispensable for SARS-CoV-2 replication. We delineate the human protein substrate landscape of 3CLpro by TAILS substrate-targeted N-terminomics. We identify more than 100 substrates in human lung and kidney cells supported by analyses of SARS-CoV-2-infected cells. Enzyme kinetics and molecular docking simulations of 3CLpro engaging substrates reveal how noncanonical cleavage sites, which diverge from SARS-CoV, guide substrate specificity. Cleaving the interactors of essential effector proteins, effectively stranding them from their binding partners, amplifies the consequences of proteolysis. We show that 3CLpro targets the Hippo pathway, including inactivation of MAP4K5, and key effectors of transcription, mRNA processing, and translation. We demonstrate that Spike glycoprotein directly binds galectin-8, with galectin-8 cleavage disengaging CALCOCO2/NDP52 to decouple antiviral-autophagy. Indeed, in post-mortem COVID-19 lung samples, NDP52 rarely colocalizes with galectin-8, unlike in healthy lungs. The 3CLpro substrate degradome establishes a foundational substrate atlas to accelerate exploration of SARS-CoV-2 pathology and drug design., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)- Published
- 2021
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30. SARS-CoV-2 spike protein S1 induces fibrin(ogen) resistant to fibrinolysis: implications for microclot formation in COVID-19.
- Author
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Grobbelaar LM, Venter C, Vlok M, Ngoepe M, Laubscher GJ, Lourens PJ, Steenkamp J, Kell DB, and Pretorius E
- Subjects
- Adult, Aged, Amyloid metabolism, Blood Platelets metabolism, Complement C3 metabolism, Female, Fibrinogen metabolism, Humans, Lung pathology, Male, Microfluidic Analytical Techniques, Middle Aged, Prothrombin metabolism, SARS-CoV-2 metabolism, Thrombosis virology, Trypsin metabolism, COVID-19 pathology, Fibrin metabolism, Fibrinolysis physiology, Spike Glycoprotein, Coronavirus metabolism, Thrombosis pathology
- Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2)-induced infection, the cause of coronavirus disease 2019 (COVID-19), is characterized by unprecedented clinical pathologies. One of the most important pathologies, is hypercoagulation and microclots in the lungs of patients. Here we study the effect of isolated SARS-CoV-2 spike protein S1 subunit as potential inflammagen sui generis. Using scanning electron and fluorescence microscopy as well as mass spectrometry, we investigate the potential of this inflammagen to interact with platelets and fibrin(ogen) directly to cause blood hypercoagulation. Using platelet-poor plasma (PPP), we show that spike protein may interfere with blood flow. Mass spectrometry also showed that when spike protein S1 is added to healthy PPP, it results in structural changes to β and γ fibrin(ogen), complement 3, and prothrombin. These proteins were substantially resistant to trypsinization, in the presence of spike protein S1. Here we suggest that, in part, the presence of spike protein in circulation may contribute to the hypercoagulation in COVID-19 positive patients and may cause substantial impairment of fibrinolysis. Such lytic impairment may result in the persistent large microclots we have noted here and previously in plasma samples of COVID-19 patients. This observation may have important clinical relevance in the treatment of hypercoagulability in COVID-19 patients., (© 2021 The Author(s).)
- Published
- 2021
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31. Persistent clotting protein pathology in Long COVID/Post-Acute Sequelae of COVID-19 (PASC) is accompanied by increased levels of antiplasmin.
- Author
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Pretorius E, Vlok M, Venter C, Bezuidenhout JA, Laubscher GJ, Steenkamp J, and Kell DB
- Subjects
- Adult, Disease Progression, Female, Humans, Male, Middle Aged, SARS-CoV-2 pathogenicity, Post-Acute COVID-19 Syndrome, Antifibrinolytic Agents metabolism, Blood Coagulation Factors metabolism, COVID-19 complications
- Abstract
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2)-induced infection, the cause of coronavirus disease 2019 (COVID-19), is characterized by acute clinical pathologies, including various coagulopathies that may be accompanied by hypercoagulation and platelet hyperactivation. Recently, a new COVID-19 phenotype has been noted in patients after they have ostensibly recovered from acute COVID-19 symptoms. This new syndrome is commonly termed Long COVID/Post-Acute Sequelae of COVID-19 (PASC). Here we refer to it as Long COVID/PASC. Lingering symptoms persist for as much as 6 months (or longer) after acute infection, where COVID-19 survivors complain of recurring fatigue or muscle weakness, being out of breath, sleep difficulties, and anxiety or depression. Given that blood clots can block microcapillaries and thereby inhibit oxygen exchange, we here investigate if the lingering symptoms that individuals with Long COVID/PASC manifest might be due to the presence of persistent circulating plasma microclots that are resistant to fibrinolysis., Methods: We use techniques including proteomics and fluorescence microscopy to study plasma samples from healthy individuals, individuals with Type 2 Diabetes Mellitus (T2DM), with acute COVID-19, and those with Long COVID/PASC symptoms., Results: We show that plasma samples from Long COVID/PASC still contain large anomalous (amyloid) deposits (microclots). We also show that these microclots in both acute COVID-19 and Long COVID/PASC plasma samples are resistant to fibrinolysis (compared to plasma from controls and T2DM), even after trypsinisation. After a second trypsinization, the persistent pellet deposits (microclots) were solubilized. We detected various inflammatory molecules that are substantially increased in both the supernatant and trapped in the solubilized pellet deposits of acute COVID-19 and Long COVID/PASC, versus the equivalent volume of fully digested fluid of the control samples and T2DM. Of particular interest was a substantial increase in α(2)-antiplasmin (α2AP), various fibrinogen chains, as well as Serum Amyloid A (SAA) that were trapped in the solubilized fibrinolytic-resistant pellet deposits., Conclusions: Clotting pathologies in both acute COVID-19 infection and in Long COVID/PASC might benefit from following a regime of continued anticlotting therapy to support the fibrinolytic system function., (© 2021. The Author(s).)
- Published
- 2021
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32. ICTV Virus Taxonomy Profile: Marnaviridae 2021.
- Author
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Lang AS, Vlok M, Culley AI, Suttle CA, Takao Y, Tomaru Y, and Ictv Report Consortium
- Subjects
- Animals, Capsid Proteins, Eukaryota, Host Specificity, Hydrobiology, Metagenomics, RNA Virus Infections virology, RNA Viruses ultrastructure, RNA, Viral, Virion classification, Virion genetics, Virion ultrastructure, Virus Replication, Genome, Viral, Phylogeny, RNA Viruses classification, RNA Viruses genetics
- Abstract
The family Marnaviridae comprises small non-enveloped viruses with positive-sense RNA genomes of 8.6-9.6 kb. Isolates infect marine single-celled eukaryotes (protists) that come from diverse lineages. Some members are known from metagenomic studies of ocean virioplankton, with additional unclassified viruses described from metagenomic datasets derived from marine and freshwater environments. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Marnaviridae , which is available at ictv.global/report/marnaviridae.
- Published
- 2021
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33. Continual proteomic divergence of HepG2 cells as a consequence of long-term spheroid culture.
- Author
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Ellero AA, van den Bout I, Vlok M, Cromarty AD, and Hurrell T
- Subjects
- Chromatography, Liquid, Gene Expression Regulation, Neoplastic, Hep G2 Cells, Humans, Spheroids, Cellular metabolism, Tandem Mass Spectrometry, Cell Culture Techniques methods, Proteomics methods, Spheroids, Cellular cytology
- Abstract
Three-dimensional models are considered a powerful tool for improving the concordance between in vitro and in vivo phenotypes. However, the duration of spheroid culture may influence the degree of correlation between these counterparts. When using immortalised cell lines as model systems, the assumption for consistency and reproducibility is often made without adequate characterization or validation. It is therefore essential to define the biology of each spheroid model by investigating proteomic dynamics, which may be altered relative to culture duration. As an example, we assessed the influence of culture duration on the relative proteome abundance of HepG2 cells cultured as spheroids, which are routinely used to model aspects of the liver. Quantitative proteomic profiling of whole cell lysates labelled with tandem-mass tags was conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In excess of 4800 proteins were confidently identified, which were shared across three consecutive time points over 28 days. The HepG2 spheroid proteome was divergent from the monolayer proteome after 14 days in culture and continued to change over the successive culture time points. Proteins representing the recognised core hepatic proteome, cell junction, extracellular matrix, and cell adhesion proteins were found to be continually modulated.
- Published
- 2021
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34. EMS Derived Wheat Mutant BIG8-1 ( Triticum aestivum L.)-A New Drought Tolerant Mutant Wheat Line.
- Author
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le Roux ML, Burger NFV, Vlok M, Kunert KJ, Cullis CA, and Botha AM
- Subjects
- Acclimatization genetics, Amino Acids metabolism, Antioxidants metabolism, Chlorophyll metabolism, Ethyl Methanesulfonate toxicity, Mutagens toxicity, Phenotype, Photosystem II Protein Complex metabolism, Plant Breeding, Plant Leaves metabolism, Plant Proteins metabolism, Proteome metabolism, Ribulose-Bisphosphate Carboxylase metabolism, Stress, Physiological genetics, Triticum drug effects, Water metabolism, Droughts, Mutation, Triticum genetics, Triticum physiology
- Abstract
Drought response in wheat is considered a highly complex process, since it is a multigenic trait; nevertheless, breeding programs are continuously searching for new wheat varieties with characteristics for drought tolerance. In a previous study, we demonstrated the effectiveness of a mutant known as RYNO3936 that could survive 14 days without water. In this study, we reveal another mutant known as BIG8-1 that can endure severe water deficit stress (21 days without water) with superior drought response characteristics. Phenotypically, the mutant plants had broader leaves, including a densely packed fibrous root architecture that was not visible in the WT parent plants. During mild (day 7) drought stress, the mutant could maintain its relative water content, chlorophyll content, maximum quantum yield of PSII (Fv/Fm) and stomatal conductance, with no phenotypic symptoms such as wilting or senescence despite a decrease in soil moisture content. It was only during moderate (day 14) and severe (day 21) water deficit stress that a decline in those variables was evident. Furthermore, the mutant plants also displayed a unique preservation of metabolic activity, which was confirmed by assessing the accumulation of free amino acids and increase of antioxidative enzymes (peroxidases and glutathione S-transferase). Proteome reshuffling was also observed, allowing slow degradation of essential proteins such as RuBisCO during water deficit stress. The LC-MS/MS data revealed a high abundance of proteins involved in energy and photosynthesis under well-watered conditions, particularly Serpin-Z2A and Z2B, SGT1 and Calnexin-like protein. However, after 21 days of water stress, the mutants expressed ABC transporter permeases and xylanase inhibitor protein, which are involved in the transport of amino acids and protecting cells, respectively. This study characterizes a new mutant BIG8-1 with drought-tolerant characteristics suited for breeding programs.
- Published
- 2021
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35. Resurrection of a Viral Internal Ribosome Entry Site from a 700 Year Old Ancient Northwest Territories Cripavirus.
- Author
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Wang X, Vlok M, Flibotte S, and Jan E
- Subjects
- Animals, DNA, Ancient, DNA, Intergenic metabolism, Feces virology, Northwest Territories, Ribosomes metabolism, Dicistroviridae genetics, Dicistroviridae physiology, Internal Ribosome Entry Sites, Reindeer virology
- Abstract
The dicistrovirus intergenic region internal ribosome entry site (IGR IRES) uses an unprecedented, streamlined mechanism whereby the IRES adopts a triple-pseudoknot (PK) structure to directly bind to the conserved core of the ribosome and drive translation from a non-AUG codon. The origin of this IRES mechanism is not known. Previously, a partial fragment of a divergent dicistrovirus RNA genome, named ancient Northwest territories cripavirus (aNCV), was extracted from 700-year-old caribou feces trapped in a subarctic ice patch. The aNCV IGR sequence adopts a secondary structure similar to contemporary IGR IRES structures, however, there are subtle differences including 105 nucleotides upstream of the IRES of unknown function. Using filter binding assays, we showed that the aNCV IRES could bind to purified ribosomes, and toeprinting analysis pinpointed the start site at a GCU alanine codon adjacent to PKI. Using a bicistronic reporter RNA, the aNCV IGR can direct translation in vitro in a PKI-dependent manner. Lastly, a chimeric infectious clone swapping in the aNCV IRES supported translation and virus infection. The characterization and resurrection of a functional IGR IRES from a divergent 700-year-old virus provides a historical framework for the importance of this viral translational mechanism.
- Published
- 2021
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36. Forager and farmer evolutionary adaptations to malaria evidenced by 7000 years of thalassemia in Southeast Asia.
- Author
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Vlok M, Buckley HR, Miszkiewicz JJ, Walker MM, Domett K, Willis A, Trinh HH, Minh TT, Nguyen MHT, Nguyen LC, Matsumura H, Wang T, Nghia HT, and Oxenham MF
- Subjects
- Asia, Southeastern epidemiology, Bone and Bones pathology, Geography, Humans, Skull diagnostic imaging, Skull pathology, Thalassemia diagnosis, Thalassemia diagnostic imaging, Adaptation, Physiological, Biological Evolution, Farmers, Malaria transmission, Thalassemia pathology
- Abstract
Thalassemias are inherited blood disorders that are found in high prevalences in the Mediterranean, Southeast Asia and the Pacific. These diseases provide varying levels of resistance to malaria and are proposed to have emerged as an adaptive response to malaria in these regions. The transition to agriculture in the Holocene has been suggested to have influenced the selection for thalassemia in the Mediterranean as land clearance for farming encouraged interaction between Anopheles mosquitos, the vectors for malaria, and human groups. Here we document macroscopic and microscopic skeletal evidence for the presence of thalassemia in both hunter-gatherer (Con Co Ngua) and early agricultural (Man Bac) populations in northern Vietnam. Firstly, our findings demonstrate that thalassemia emerged prior to the transition to agriculture in Mainland Southeast Asia, from at least the early seventh millennium BP, contradicting a long-held assumption that agriculture was the main driver for an increase in malaria in Southeast Asia. Secondly, we describe evidence for significant malarial burden in the region during early agriculture. We argue that the introduction of farming into the region was not the initial driver of the selection for thalassemia, as it may have been in other regions of the world.
- Published
- 2021
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37. Dysregulated healing responses in diabetic wounds occur in the early stages postinjury.
- Author
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Boodhoo K, Vlok M, Tabb DL, Myburgh KH, and van de Vyver M
- Subjects
- Animals, Body Fluids metabolism, Chronic Disease, Cytokines metabolism, Matrix Metalloproteinase 9 metabolism, Mice, Inbred C57BL, Mice, Obese, Proteome metabolism, Substance P metabolism, Mice, Diabetes Mellitus, Experimental pathology, Wound Healing, Wounds and Injuries pathology
- Abstract
Chronic wounds are a serious and debilitating complication of diabetes. A better understanding of the dysregulated healing responses following injury will provide insight into the optimal time frame for therapeutic intervention. In this study, a direct comparison was done between the healing dynamics and the proteome of acute and obese diabetic wounds on days 2 and 7 following injury. Full thickness excisional wounds were induced on obese diabetic (B6.Cg-lepob/J, ob/ob, n = 14) (blood glucose 423.25 ± 127.92 mg/dL) and WT control (C57BL/6J, n = 14) (blood glucose 186.67 ± 24.5 mg/dL) mice. Histological analysis showed no signs of healing in obese DM wounds whereas complete wound closure/re-epithelisation, the formation of granulation tissue and signs of re-vascularisation, was evident in acute wounds on day 7. In obese DM wounds, substance P deficiency and increased MMP-9 activity on day 2 coincided with increased cytokine/chemokine levels within wound fluid. LC-MS/MS identified 906 proteins, of which 23 (Actn3, Itga6, Epb41, Sncg, Nefm, Rsp18, Rsp19, Rpl22, Macroh2a1, Rpn1, Ppib, Snrnp70, Ddx5, Eif3g, Tpt1, FABP5, Cavin1, Stfa1, Stfa3, Cycs, Tkt, Mb, Chmp2a) were differentially expressed in wounded tissue on day 2 (P < 0.05; more than two-fold) and 6 (Cfd, Ptms, Hp, Hmga1, Cbx3, Syap1) (P < 0.05; more than two-fold) on day 7. A large number of dysregulated proteins on day 2 was associated with an inability to progress into the proliferative stage of healing and suggest that early intervention might be pivotal for effective healing outcomes. The proteomic approach highlighted the complexity of obese DM wounds in which the dysregulation involves multiple regulatory pathways and biological processes.
- Published
- 2021
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38. Wheat Line "RYNO3936" Is Associated With Delayed Water Stress-Induced Leaf Senescence and Rapid Water-Deficit Stress Recovery.
- Author
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le Roux ML, Burger NFV, Vlok M, Kunert KJ, Cullis CA, and Botha AM
- Abstract
Random mutagenesis was applied to produce a new wheat mutant (RYNO3926) with superior characteristics regarding tolerance to water deficit stress induced at late booting stage. The mutant also displays rapid recovery from water stress conditions. Under water stress conditions mutant plants reached maturity faster and produced more seeds than its wild type wheat progenitor. Wild-type Tugela DN plants died within 7 days after induction of water stress induced at late booting stage, while mutant plants survived by maintaining a higher relative moisture content (RMC), increased total chlorophyll, and a higher photosynthesis rate and stomatal conductance. Analysis of the proteome of mutant plants revealed that they better regulate post-translational modification (SUMOylation) and have increased expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) proteins. Mutant plants also expressed unique proteins associated with dehydration tolerance including abscisic stress-ripening protein, cold induced protein, cold-responsive protein, dehydrin, Group 3 late embryogenesis, and a lipoprotein (LAlv9) belonging to the family of lipocalins. Overall, our results suggest that our new mutant RYNO3936 has a potential for inclusion in future breeding programs to improve drought tolerance under dryland conditions., (Copyright © 2020 le Roux, Burger, Vlok, Kunert, Cullis and Botha.)
- Published
- 2020
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39. Non-pharmacological and pharmacological approaches for psychiatric disorders: Re-appraisal and insights from zebrafish models.
- Author
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de Abreu MS, Giacomini ACVV, Genario R, Rech N, Carboni J, Lakstygal AM, Amstislavskaya TG, Demin KA, Leonard BE, Vlok M, Harvey BH, Piato A, Barcellos LJG, and Kalueff AV
- Subjects
- Animals, Behavior, Animal drug effects, Disease Models, Animal, Female, Humans, Male, Mental Disorders etiology, Stress, Psychological complications, Treatment Outcome, Anti-Anxiety Agents therapeutic use, Antidepressive Agents therapeutic use, Complementary Therapies methods, Mental Disorders drug therapy, Rodentia, Zebrafish
- Abstract
Acute and chronic stressors are common triggers of human mental illnesses. Experimental animal models and their cross-species translation to humans are critical for understanding of the pathogenesis of stress-related psychiatric disorders. Mounting evidence suggests that both pharmacological and non-pharmacological approaches can be efficient in treating these disorders. Here, we analyze human, rodent and zebrafish (Danio rerio) data to compare the impact of non-pharmacological and pharmacological therapies of stress-related psychopathologies. Emphasizing the likely synergism and interplay between pharmacological and environmental factors in mitigating daily stress both clinically and in experimental models, we argue that environmental enrichment emerges as a promising complementary therapy for stress-induced disorders across taxa. We also call for a broader use of novel model organisms, such as zebrafish, to study such treatments and their potential interplay., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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40. Sensationalism and speaking to the public: Scientific rigour and interdisciplinary collaborations in palaeopathology.
- Author
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Snoddy AME, Beaumont J, Buckley HR, Colombo A, Halcrow SE, Kinaston RL, and Vlok M
- Subjects
- Biomedical Research standards, Humans, Periodicals as Topic standards, Publishing standards, Communication, Paleopathology standards
- Abstract
Objectives: In this brief communication we discuss issues concerning scientific rigour in palaeopathological publications, particularly studies published in clinical or general science journals, that employ skeletal analysis to elucidate the lives and deaths of historical figures or interpret "mysterious" assemblages or burials. We highlight the relationship between poor methodological rigour and lack of interdisciplinary communication, and discuss how this can result in scientifically weak, sensational narratives being presented to the public., Conclusions: Although most high profile publications involving analysis of archaeological human remains are methodologically sound and well interpreted, others have suffered from poor scientific rigour stemming from an apparent lack of awareness of anthropological methods and ethics. When these publications are highlighted by the press, sensationalistic narratives are perpetuated which may reflect poorly on our discipline and give the public unrealistic expectations about our work., Suggestions for Future Research: We suggest that best practice in high-profile paleopathological research include recruitment of a range of authors and reviewers from clinical sciences, anthropology, and the humanities, consideration of the ethical issues surrounding retrospective diagnosis, and transparency with the press in regards to the limitations inherent in this kind of work., (Copyright © 2020 Elsevier Inc. All rights reserved.)
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- 2020
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41. Application of a sequence-based taxonomic classification method to uncultured and unclassified marine single-stranded RNA viruses in the order Picornavirales .
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Vlok M, Lang AS, and Suttle CA
- Abstract
Metagenomics has altered our understanding of microbial diversity and ecology. This includes its applications to viruses in marine environments that have demonstrated their enormous diversity. Within these are RNA viruses, many of which share genetic features with members of the order Picornavirales ; yet, very few of these have been taxonomically classified. The only recognized family of marine RNA viruses is the Marnaviridae , which was founded based on discovery and characterization of the species Heterosigma akashiwo RNA virus . Two additional genera of marine RNA viruses, Labyrnavirus (one species) and Bacillarnavirus (three species), were subsequently defined within the order Picornavirales but not assigned to a family. We have defined a sequence-based framework for taxonomic classification of twenty marine RNA viruses into the family Marnaviridae . Using RNA-dependent RNA polymerase (RdRp) phylogeny and distance-based analyses, we assigned the genera Labyrnavirus and Bacillarnavirus to the family Marnaviridae and created four additional genera in the family: Locarnavirus (four species), Kusarnavirus (one species), Salisharnavirus (four species) and Sogarnavirus (six species). We used pairwise capsid protein comparisons to delineate species within families, with 75 per cent identity as the species demarcation threshold. The family displays high sequence diversities and Jukes-Cantor distances for both the RdRp and capsid genes, suggesting that the classified viruses are not representative of all of the virus diversity within the family and that there are many more extant taxa. Our proposed taxonomic framework provides a sound classification system for this group of viruses that will have broadly applicable principles for other viral groups. It is based on sequence data alone and provides a robust taxonomic framework to include viruses discovered via metagenomic studies, thereby greatly expanding the realm of viruses subject to taxonomic classification., (© The Author(s) 2019. Published by Oxford University Press.)
- Published
- 2019
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42. Cleavage and Sub-Cellular Redistribution of Nuclear Pore Protein 98 by Coxsackievirus B3 Protease 2A Impairs Cardioprotection.
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Hanson PJ, Hossain AR, Qiu Y, Zhang HM, Zhao G, Li C, Lin V, Sulaimon S, Vlok M, Fung G, Chen VH, Jan E, McManus BM, Granville DJ, and Yang D
- Subjects
- Animals, Disease Models, Animal, Gene Expression, HeLa Cells, Humans, Mice, Models, Biological, Neuregulin-1 metabolism, Presenilin-1 metabolism, Protein Transport, Proteolysis, Coxsackievirus Infections pathology, Cysteine Endopeptidases metabolism, Enterovirus B, Human growth & development, Host-Pathogen Interactions, Myocarditis pathology, Myocardium pathology, Nuclear Pore Complex Proteins metabolism, Viral Proteins metabolism
- Abstract
Myocarditis, inflammation of the heart muscle, affects all demographics and is a major cause of sudden and unexpected death in young people. It is most commonly caused by viral infections of the heart, with coxsackievirus B3 (CVB3) being among the most prevalent pathogens. To understand the molecular pathogenesis of CVB3 infection and provide strategies for developing treatments, we examined the role of a key nuclear pore protein 98 (NUP98) in the setting of viral myocarditis. NUP98 was cleaved as early as 2 h post-CVB3 infection. This cleavage was further verified through both the ectopic expression of viral proteases and in vitro using purified recombinant CVB3 proteases (2A and 3C), which demonstrated that CVB3 2A but not 3C is responsible for this cleavage. By immunostaining and confocal imaging, we observed that cleavage resulted in the redistribution of NUP98 to punctate structures in the cytoplasm. Targeted siRNA knockdown of NUP98 during infection further increased viral protein expression and viral titer, and reduced cell viability, suggesting a potential antiviral role of NUP98. Moreover, we discovered that expression levels of neuregulin-1 (NRG1), a cardioprotective gene, and presenilin-1 (PSEN1), a cellular protease processing the tyrosine kinase receptor ERBB4 of NRG1, were reliant upon NUP98 and were downregulated during CVB3 infection. In addition, expression of these NUP98 target genes in myocardium tissue not only occurred at an earlier phase of infection, but also appeared in areas away from the initial inflammatory regions. Collectively, CVB3-induced cleavage of NUP98 and subsequent impairment of the cardioprotective NRG1-ERBB4/PSEN1 signaling cascade may contribute to increased myocardial damage in the context of CVB3-induced myocarditis. To our knowledge, this is the first study to demonstrate the link between NUP98 and the NRG1 signaling pathway in viral myocarditis.
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- 2019
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43. Marine RNA Virus Quasispecies Are Distributed throughout the Oceans.
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Vlok M, Lang AS, and Suttle CA
- Subjects
- Evolution, Molecular, Genetic Variation, Genotype, Geography, Picornaviridae classification, Picornaviridae isolation & purification, Seawater virology, Genome, Viral, Oceans and Seas, Quasispecies, RNA Viruses classification, RNA Viruses isolation & purification
- Abstract
RNA viruses, particularly genetically diverse members of the Picornavirales , are widespread and abundant in the ocean. Gene surveys suggest that there are spatial and temporal patterns in the composition of RNA virus assemblages, but data on their diversity and genetic variability in different oceanographic settings are limited. Here, we show that specific RNA virus genomes have widespread geographic distributions and that the dominant genotypes are under purifying selection. Genomes from three previously unknown picorna-like viruses (BC-1, -2, and -3) assembled from a coastal site in British Columbia, Canada, as well as marine RNA viruses JP-A, JP-B, and Heterosigma akashiwo RNA virus exhibited different biogeographical patterns. Thus, biotic factors such as host specificity and viral life cycle, and not just abiotic processes such as dispersal, affect marine RNA virus distribution. Sequence differences relative to reference genomes imply that virus quasispecies are under purifying selection, with synonymous single-nucleotide variations dominating in genomes from geographically distinct regions resulting in conservation of amino acid sequences. Conversely, sequences from coastal South Africa that mapped to marine RNA virus JP-A exhibited more nonsynonymous mutations, probably representing amino acid changes that accumulated over a longer separation. This biogeographical analysis of marine RNA viruses demonstrates that purifying selection is occurring across oceanographic provinces. These data add to the spectrum of known marine RNA virus genomes, show the importance of dispersal and purifying selection for these viruses, and indicate that closely related RNA viruses are pathogens of eukaryotic microbes across oceans. IMPORTANCE Very little is known about aquatic RNA virus populations and genome evolution. This is the first study that analyzes marine environmental RNA viral assemblages in an evolutionary and broad geographical context. This study contributes the largest marine RNA virus metagenomic data set to date, substantially increasing the sequencing space for RNA viruses and also providing a baseline for comparisons of marine RNA virus diversity. The new viruses discovered in this study are representative of the most abundant family of marine RNA viruses, the Marnaviridae , and expand our view of the diversity of this important group. Overall, our data and analyses provide a foundation for interpreting marine RNA virus diversity and evolution., (Copyright © 2019 Vlok et al.)
- Published
- 2019
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44. Metagenomes of a Freshwater Charavirus from British Columbia Provide a Window into Ancient Lineages of Viruses.
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Vlok M, Gibbs AJ, and Suttle CA
- Subjects
- British Columbia, Fresh Water virology, Phylogeny, RNA Viruses enzymology, RNA Viruses isolation & purification, RNA-Dependent RNA Polymerase genetics, Sequence Homology, Amino Acid, Tobamovirus genetics, Evolution, Molecular, Metagenome, RNA Viruses genetics
- Abstract
Charophyte algae, not chlorophyte algae, are the ancestors of 'higher plants'; hence, viruses infecting charophytes may be related to those that first infected higher plants. Streamwaters from British Columbia, Canada, yielded single-stranded RNA metagenomes of Charavirus canadensis (CV-Can), that are similar in genomic architecture, length (9593 nt), nucleotide identity (63.4%), and encoded amino-acid sequence identity (53.0%) to those of Charavirus australis (CV-Aus). The sequences of their RNA-dependent RNA-polymerases (RdRp) resemble those found in benyviruses, their helicases those of hepaciviruses and hepegiviruses, and their coat-proteins (CP) those of tobamoviruses; all from the alphavirus/flavivirus branch of the 'global RNA virome'. The 5'-terminus of the CV-Can genome, but not that of CV-Aus, is complete and encodes a methyltransferase domain. Comparisons of CP sequences suggests that Canadian and Australian charaviruses diverged 29⁻46 million years ago (mya); whereas, the CPs of charaviruses and tobamoviruses last shared a common ancestor 212 mya, and the RdRps of charaviruses and benyviruses 396 mya. CV-Can is sporadically abundant in low-nutrient freshwater rivers in British Columbia, where Chara braunii , a close relative of C. australis , occurs, and which may be its natural host. Charaviruses, like their hosts, are ancient and widely distributed, and thus provide a window to the viromes of early eukaryotes and, even, Archaea., Competing Interests: The authors declare that they have no conflict of interest.
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- 2019
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45. 11-Ketotestosterone and 11-Ketodihydrotestosterone in Castration Resistant Prostate Cancer: Potent Androgens Which Can No Longer Be Ignored.
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Pretorius E, Africander DJ, Vlok M, Perkins MS, Quanson J, and Storbeck KH
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- Androgens metabolism, Animals, Biosynthetic Pathways, Cell Line, Tumor, Cell Proliferation, Humans, Male, Protein Binding, Receptors, Androgen metabolism, Response Elements, Testosterone metabolism, Prostatic Neoplasms, Castration-Resistant metabolism, Testosterone analogs & derivatives
- Abstract
Dihydrotestosterone (DHT) is regarded as the most potent natural androgen and is implicated in the development and progression of castration resistant prostate cancer (CRPC). Under castrate conditions, DHT is produced from the metabolism of the adrenal androgen precursors, DHEA and androstenedione. Recent studies have shown that the adrenal steroid 11β-hydroxyandrostenedione (11OHA4) serves as the precursor to the androgens 11-ketotestosterone (11KT) and 11-ketodihydrotestosterone (11KDHT). In this study we comprehensively assess the androgenic activity of 11KT and 11KDHT. This is the first study, to our knowledge, to show that 11KT and 11KDHT, like T and DHT, are potent and efficacious agonists of the human androgen receptor (AR) and induced both the expression of representative AR-regulated genes as well as cellular proliferation in the androgen dependent prostate cancer cell lines, LNCaP and VCaP. Proteomic analysis revealed that 11KDHT regulated the expression of more AR-regulated proteins than DHT in VCaP cells, while in vitro conversion assays showed that 11KT and 11KDHT are metabolized at a significantly lower rate in both LNCaP and VCaP cells when compared to T and DHT, respectively. Our findings show that 11KT and 11KDHT are bona fide androgens capable of inducing androgen-dependant gene expression and cell growth, and that these steroids have the potential to remain active longer than T and DHT due to the decreased rate at which they are metabolised. Collectively, our data demonstrates that 11KT and 11KDHT likely play a vital, but overlooked, role in the development and progression of CRPC.
- Published
- 2016
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46. Impaired Energy Metabolism and Disturbed Dopamine and Glutamate Signalling in the Striatum and Prefrontal Cortex of the Spontaneously Hypertensive Rat Model of Attention-Deficit Hyperactivity Disorder.
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Dimatelis JJ, Hsieh JH, Sterley TL, Marais L, Womersley JS, Vlok M, and Russell VA
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- Animals, Rats, Rats, Inbred SHR, Rats, Wistar, Synaptic Transmission, Attention Deficit Disorder with Hyperactivity metabolism, Corpus Striatum metabolism, Dopamine metabolism, Energy Metabolism, Glutamic Acid metabolism, Prefrontal Cortex metabolism, Proteome metabolism
- Abstract
Attention deficit hyperactivity disorder (ADHD) is a heterogeneous behavioural disorder that affects 3-15 % of children worldwide. Spontaneously hypertensive rats (SHR) display the major symptoms of ADHD (hyperactivity, impulsivity and poor performance in tasks that require sustained attention) and are widely used to model the disorder. The present study aimed to test the hypothesis that SHR have a diminished capacity to generate ATP required for rapid synchronized neuronal firing, failure of which might lead to disturbances in neurotransmission that could contribute to their ADHD-like behaviour. Duplicate pooled (n = 5) samples of prefrontal cortex and striatum of prepubertal (35-day-old) SHR and Wistar Kyoto (WKY) rats were subjected to iTRAQ labeling and matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS). The MS/MS spectra were analyzed with ProteinPilot using the Ratus ratus database. Proteins detected with >95 % confidence were tested. SHR had decreased levels of several proteins involved in energy metabolism, cytoskeletal structure, myelination and neurotransmitter function when compared to WKY. Differences in protein levels between SHR and WKY were similar in prefrontal cortex and striatum, suggesting global changes in cortico-striato-thalamo-cortical circuits.
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- 2015
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47. An encapsidated viral protein and its role in RNA packaging by a non-enveloped animal RNA virus.
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Mendes A, Vlok M, Short JR, Matsui T, and Dorrington RA
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- Animals, Capsid metabolism, Insect Viruses genetics, RNA Viruses genetics, RNA, Viral genetics, Viral Proteins genetics, Viral Proteins metabolism, Insect Viruses physiology, Lepidoptera virology, RNA Viruses physiology, RNA, Viral metabolism, Virus Assembly
- Abstract
Alphatetraviruses are small (+) ssRNA viruses with non-enveloped, icosahedral, T=4 particles that assemble from 240 copies of a single capsid protein precursor. This study is focused on the mechanisms underlying selection and packaging of genomic vRNAs by Helicoverpa armigera stunt virus. We demonstrate that the viral protein, p17, is packaged at low levels (between 4 and 8 copies per capsid) raising the possibility of icosahedral asymmetry in wild-type particles. p17 promotes packaging of vRNA2 by virus-like particles (VLPs) generated from plasmid-expressed vRNA2. The 5' and 3' UTRs of RNA2 are not required for encapsidation. VLPs produced by recombinant baculoviruses package vRNA2 at detectable levels even in the absence of p17 and apparently excluding baculoviral transcripts. This suggests a role for p17 in vRNA selectivity. This is one of few examples of the packaging of a minor non-structural protein by (+) ssRNA animal viruses., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2015
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