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In many countries, smallholder farmers play a key role in food crop seed production. So far, the community roles, operational structures, seed production efficiency, aspects of sustainability, and the social and policy environments in which these groups operate have been poorly studied and described. The present study attempts to better understand these factors by drawing cases from twenty-five seed producer groups in five countries (Vietnam, Uganda, Zambia, Niger, and Guatemala) that deal with nine crops in total (rice, maize, sorghum, pearl millet, common bean, cowpea, soybean, groundnut, potato and sweet potato). Results of the study show all groups supply a significant share of seed offered in local markets. It appeared that all groups received major support for capacity development from a broad range of actors including local and national governments, public institutions, national seed companies and development organizations. Several groups operate under seasonal contracts with institutional seed buyers, whereas other groups sell most of their seed in local markets to fellow farmers. To support seed quality and render product branding meaningful, most groups have established subgroups for crop monitoring and seed inspection, and for gathering and using market intelligence. Some, but not all groups depend on formal seed certification. Two key challenges stand out across seed producer groups interviewed. First, most seed producer groups experience difficulties in accessing good-quality early generation seed (EGS) on time, like in the formal seed sector in many countries. Second, in most groups packaging and labelling of the seed produced and offered in local markets is suboptimal, hindering further professionalization. Moreover, groups invariably have a poor understanding of applicable seed policy and legislation. Our observations point at actions that external stakeholders could undertake to strengthen smallholder farmer seed production in recognition of their contribution to food and nutrition security.

Knowledge of the genetic landscape of a specific population group is vital for population-specific diagnosis and treatment of familial breast cancer. Although BRCA-related diagnostic testing has long been implemented in South Africa, the genotyping approach previously failed for the SA Indian population as it was based on other SA population groups. Because this population is uniquely admixed, the lack of population-specific data resulted in the implementation of comprehensive mutation screens for BRCA1/2. A total of 223 female patients were screened for clinically actionable variants. High-resolution melting analysis (HRMA) was used to screen 88 patients for DNA alterations in the coding and splice site boundaries of BRCA1 exons 2-9, BRCA1 exons 11-23, BRCA2 exons 2-9 and BRCA2 exons 12-27. The protein truncation test (PTT) was used to screen the three larger exons (BRCA1 exon 10 and BRCA2 exons 10 and 11) for protein termination changes. Multiplex ligation-dependent probe amplification (MLPA) was used to determine the presence of larger indels and possible copy number differences. Next Generation Sequencing (NGS) was performed on the remaining 135 samples. All potential variants were confirmed by performing Sanger DNA sequencing. The search revealed 28 different pathogenic heterozygotic variants, together with nine variants of unknown significance (VUS). The results suggested that the SA Indian population represents a different genetic admixture compared to that of mainland India, as only five pathogenic variants corresponded to those reported for mainland India. Familial breast cancer testing for SA Indian patients should therefore be performed as comprehensively as possible as the pathogenic variants seem to be family- rather than population-specific. Furthermore, predictive testing of family members will contribute to relieve the financial burden on the country's healthcare system, as increased surveillance and appropriate management could prevent disease.

Observational studies of extreme daily and subdaily precipitation-temperature sensitivities (apparent scaling) aim to provide evidence and improved understanding of how extreme precipitation will respond to a warming climate. However, interpretation of apparent scaling results is hindered by large variations in derived scaling rates and divergence from theoretical and modelled projections of systematic increases in extreme precipitation intensities (climate scaling). In warmer climatic regions, rainfall intensity has been reported to increase with temperature to a maximum before decreasing, creating a second order discontinuity or “hook” like structure. Here we investigate spatial and temporal discrepancies in apparent scaling results by isolating rainfall events and conditioning event precipitation on duration. We find that previously reported negative apparent scaling at higher temperatures which creates the hook structure, is the result of a decrease in the duration of the precipitation event, and not to the decrease in precipitation rate. We introduce standardized pooling using long records of Australian station data across climate zones, to show average precipitation intensities and 1-h peak precipitation intensities increase with temperature across all event durations and locations investigated. For shorter duration events (< 6-h), average precipitation intensity scaling is in line with the expected Clausius- Clapeyron (CC) relation at ~7 %/°C, and this decreases with increasing duration, down to 2 %/°C at 24-h duration. Consistent with climate scaling derived from model projections, 1-h peak precipitation intensities are found to increase with temperature at elevated rates compared to average precipitation intensities, with super-CC scaling (10 – 14 %/°C) found for short-duration events in tropical climates.

In contrast to many other countries, the virulence and genetic diversity of the South African Puccinia triticina population before 1980 is unknown, because of the absence of regular and systematic race analysis data and viable rust cultures. Herbarium specimens housed at the National Collection of Fungi, Biosystematics Unit, Plant Health and Protection, Agricultural Research Council, Pretoria, South Africa (SA), provided the opportunity to investigate the genetic development of the population using isolates collected between 1906 and 2010. Five subpopulations that survived between 21 and 82 years in the field were found. While three of these could represent the original races that entered SA during European settlement, two appear to be recent exotic introductions into SA, most probably from other African countries. The demise of the three oldest subpopulations might be from the release of resistant wheat cultivars. The population is clonal, where new virulence develops through single step mutations and selection for virulence. Although a possible case of somatic hybridization was found, sexual reproduction appears to be absent in SA. This study confirmed the importance of annual surveys in SA and its neighboring countries for the timely detection of new virulent races that could threaten wheat production in SA.

Polymeric drug releasing systems have numerous applications for the treatment of chronic diseases and traumatic injuries. In this study, a simple, cost-effective, and scalable method for dry spinning of crosslinked polyvinyl alcohol (PVA) fibers is presented. This method utilizes an entangled solution of PVA to form liquid bridges that are drawn into rapidly drying fibers through extensional flow. The fibers are crosslinked by a one-pot reaction in which glyoxal is introduced to the PVA solution prior to contact drawing. Failure analysis of fiber formation is used to understand the interplay of polymer concentration, glyoxal concentration, and crosslinking time to identify appropriate formulations for the production of glyoxal-crosslinked PVA fibers. The small molecule quercetin (an anti-inflammatory plant flavonoid) can be added to the one-pot reaction and is shown to be incorporated into the fibers in a concentration-dependent manner. Upon rehydration in an aqueous medium, the glyoxal-crosslinked PVA fiber scaffolds retain their morphology and slowly degrade, as measured over the course of 10 days. As the scaffolds degrade, they release the loaded quercetin, reaching a cumulative release of 56 ± 6% of the loaded drug after 10 days. The bioactivity of the released quercetin is verified by combining quercetin-loaded fibers with contact-drawn polyethylene oxide-type I collagen (PEO-Col) fibers and monitoring the growth of PC12 cells on the fibers. PC12 cells readily attach to the PEO-Col fibers and display increased nerve growth factor-induced elongation and neurite formation in the presence of quercetin-loaded PVA fibers relative to substrates formed from only PEO-Col fibers or PEO-Col and PVA fibers without quercetin.

Sunflower (Helianthus annuus L.) is the third largest grain crop by area planted in South Africa (SA). The annual yield is negatively affected by sunflower rust caused by Puccinia helianthi Schw. (Phe). Four Phe races were described in SA in the middle 1990s, but since then, no new race descriptions have been conducted. This has resulted in an information gap on the current Phe population, making it difficult to explain increased disease incidence and loss of resistance in previously resistant hybrids. To address this, 114 Phe field isolates along with 23 historic isolates were phenotyped using the international set of 11 sunflower differentials containing the R1, R2/R10, R3, R4a, R4b, R4c, R4d, R5, Pu6, and Radv resistance genes. Three new Phe races were identified, bringing the total number of South African races recorded to seven. No avirulence was detected attributable to the R1 gene, with the R4d and Radv genes remaining effective. Four main genetic lineages were detected with no obvious correlation between phenotype and genotype. The detection of three genetic lineages consisting exclusively of field isolates collected post-2006 suggested the possible recent entry of exotic introductions into SA. This, combined with the fact that one lineage consisted exclusively of the most virulent race Phe7721, confirmed a clear shift in the Phe population that could explain the increased virulence and occurrence of the disease in SA.

Dental implant clinical success is dependent on effective peri-implant tissue attachment to the trans-mucosal portion following placement. Modification of transmucosal implant surfaces can improve cellular adhesion and function leading to formation of an effective soft-tissue seal during healing, of which gingival fibroblasts are prominent cells to migrate to repair wounds and crucial for the development of a collagen rich connective tissue. Biocompatible loaded scaffold materials have been developed to allow local release of molecules with effective biological activity. Our previous studies indicate that strontium can promote gingival fibroblast metabolism, decrease apoptosis and support adhesion to titanium healing abutments. In this study, we developed a strontium-loaded alginate hydrogel scaffold which can be easily personalized to fit over any size and shape of implant transmucosal collar or healing abutment. Results indicate that biologically active strontium ions are effectively released from loaded alginate hydrogel material to promote fibroblast viability and migration to repair in vitro wounds similar to that of strontium citrate solution. Overall, this novel strontium-loaded alginate scaffold device displays good biocompatibility and functionality, demonstrating high potential as a system to provide local delivery of strontium to improve peri-implant mucosal healing following implant placement and clinical success.

This study investigated the antibacterial, cytotoxicity, and mechanical properties of a dental adhesive modified with quaternary ammonium monomer ((2-acryloyloxyethyl)dimethyldodecylammonium bromide) and cross-linker (bis(2-acryloyloxyethyl)methyldodecylammonium bromide). Monomer (M), cross-linker (C), or a combination of these (M + C) were incorporated into adhesive Adper Single Bond Plus (SB) in 5, 10, or 25% (as wt%). A colony-forming unit and MTT assays were used to evaluate antibacterial properties against Streptococcus mutans and cell viability. Resin-dentin beams (0.9 ± 0.1 mm2) were evaluated for micro-tensile bond strength (μTBS) after 24 h, 6 months, and 3 years. Hourglass specimens were evaluated for ultimate tensile strength (UTS) after 24 h, 1 week, and 6 months. Micro-hardness measurements after softening in ethanol were taken as an indirect assessment of the polymer cross-linking density. Kruskal-Wallis, one-way ANOVA, two-way ANOVA, and Student’s t test were used for analysis of the antibacterial, cytotoxicity, μTBS, UTS, and hardness data, all with a significance level of p < 0.05. 10%M and 25%M demonstrated a significant reduction in S. mutans relative to SB (p < 0.001). No differences in cytotoxicity were detected for any of the groups. After 6 months, no changes in μTBS were shown for any of the groups. After 3 years, all groups evidenced a significant decrease in μTBS (p < 0.05) except 5%M, 5%C, and 5%M + 5%C. All groups demonstrated either stable or significantly increased UTS after 6 months. Except for the cross-linker groups, a significant decrease in micro-hardness was shown for all groups after softening in ethanol (p < 0.05). A 5–10% of monomer may render the resin antibacterial without a compromise to its mechanical and bonding properties. Biomodification of a resin adhesive with an antibacterial monomer and cross-linker may help improve the life span of adhesive restorations.

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch Research Council (NWO) RAAK-PRO grant Background Fear of movement (kinesiophobia) after cardiac hospitalization is associated with low physical activity levels and reduced quality of life. Participation in cardiac rehabilitation (CR) improves psychological wellbeing and relieves kinesiophobia. However, little is known about the predictors of kinesiophobia and the impact of kinesiophobia on participation in CR. Purpose To identify predictors of kinesiophobia after (acute) cardiac hospitalization and to assess the impact of kinesiophobia on participation in CR. Methods We performed a longitudinal study in patients with coronary artery disease, acute heart failure or atrial fibrillation. At hospital discharge we collected demographic variables, cardiac disease history and administered questionnaires about kinesiophobia, cardiac anxiety, depression and psychological complexity (severity of psychological problems). Kinesiophobia was measured with the Tampa Scale for Kinesiophobia (TSK), scores >28 are considered `high levels of kinesiophobia’. At 3 months patients were followed up to evaluate participation in CR. We investigated (1) predictors of kinesiophobia at hospital discharge and (2) the impact of kinesiophobia on participation in CR at 3-months follow up, using two multivariable logistic regression models with backward elimination to identify predictors. Results In 149 patients (22% women), mean age 64.1 (±10.1) high levels of kinesiophobia were measured in 61 patients (40,9%). Higher age decreased the odds for kinesiophobia: OR: 0.95 (95%CI:0.89 – 0.99). Two variables increased the odds for kinesiophobia: higher levels of psychological complexity: OR: 1.27 (95%CI 1.01- 1.60) and cardiac anxiety: OR: 1.10 (95%CI: 1.02 – 1.19). The odds for participating in CR were decreased by kinesiophobia: OR: 0.91 (95%CI: 0.84 – 0.99) and higher age: OR: 0.92 (95%CI:0.86-0.98). Conclusion(s) Kinesiophobia at hospital discharge is associated with psychological complexity and negatively impacts participation in CR. This study emphasizes the need for early screening to identify those who are at risk of developing kinesiophobia which in turn can lead to non-adherence to CR.

Parasexuality contributes to diversity and adaptive evolution of haploid (monokaryotic) fungi. However, non-sexual genetic exchange mechanisms are not defined in dikaryotic fungi (containing two distinct haploid nuclei). Newly emerged strains of the wheat stem rust pathogen, Puccinia graminis f. sp. tritici (Pgt), such as Ug99, are a major threat to global food security. Here, we provide genomics-based evidence supporting that Ug99 arose by somatic hybridisation and nuclear exchange between dikaryons. Fully haplotype-resolved genome assembly and DNA proximity analysis reveal that Ug99 shares one haploid nucleus genotype with a much older African lineage of Pgt, with no recombination or chromosome reassortment. These findings indicate that nuclear exchange between dikaryotes can generate genetic diversity and facilitate the emergence of new lineages in asexual fungal populations., Strain Ug99 of the wheat stem rust pathogen, Puccinia graminis f. sp. tritici, is a major threat to global food security. Here, the authors present genomic analyses supporting that Ug99 arose as a result of non-sexual genetic exchange between dikaryotic ancestors.

Puccinia graminis f. sp. avenae (Pga) samples were collected from cultivated oat (Avena sativa L.) in trial plots and commercial fields and from wild oat (Avena spp.) during the 2016 and 2017 seasons. Field samples were purified through selection of single pustule isolates and subsequent urediniospore increases using the susceptible cultivar Swan. For race phenotyping, a set of 12 international differential lines was used that resulted in the identification of races RSJ, RJS and RJJ. Race RSJ was the most prevalent (60% of isolates) followed by races RJS (34%) and RJJ (6%). These races varied in virulence for Pg6 and Pg12, with no avirulence recorded for Pg1, 2, 4, 8, 9, 13 and Pg15 and no virulence for Pg3, 10 and Pg16. Seedling infection types of 32 oat cultivars to the three described races showed compatible phenotypes for all cultivars towards at least one of the races. Moderate levels of adult plant resistance against races RJS and RSJ were recorded for seven cultivars during field tests in 2017 and 2018. Thirteen microsatellite markers used to assess genetic variability amongst twenty four field isolates revealed three sub-populations of which only one correlated with the race phenotype. The results contributed to our understanding of the diversity of the Pga population in South Africa, including useful resistance sources and cultivar responses.

The mechanical stability and long-term success of an implant depends on the early healing phase and osseointegration of the bone around it. In addition, a healthy gingival tissue around the implant acts as a barrier that prevents bacteria and pathological byproducts from reaching the implant site. This study investigated the in-vitro attachment and spreading of human gingival fibroblasts (HGF) on bacterial grade polystyrene (PS) at different distances from radio-frequency glow-discharge (RFGD)-treated commercially pure titanium (cpTi) specimens. Controls included sterile cpTi specimens without RFGD treatment. A second set of experiments utilized media transferred to new bacterial grade polystyrene dishes (no cpTi) after the medium was conditioned by exposure to cpTi, either with or without RFGD treatment, for 24 hr. Surface characterization of the dishes was conducted through contact angle measurements and infrared spectroscopy. Cell numbers and surface areas were determined from Image J analysis of multiple microscopic images of fixed, stained cells. The results showed significantly greater numbers and surface areas on bacterial grade PS dishes at distances up to 15 mm from the RFGD-treated cpTi groups than for the controls. Moreover, a significant effect of the conditioned medium from RFGD-treated cpTi versus control cultures was shown on the numbers of fibroblasts attached to bacterial grade polystyrene dishes after 24 hr (p < 0.005) and 48 hr (p = 0.002) incubation. Surface areas of cells exposed to conditioned medium were not significantly different (p ≥ 0.05). Surface characterization of the PS dishes showed a higher value of the critical surface tensions of the treated group when compared to the control group.

This work reports on polymer-antibiotic conjugates (PACs) as additives to resin-based restorative dental materials as a new strategy to convey sustained antibacterial character to these materials. Such antibacterial performance is expected to improve their longevity in the oral cavity. Using the previously reported ciprofloxacin (Cip)-based PAC as a control, a penicillin V (PV)-based PAC was investigated. The monomer-antibiotic conjugate (MAC) containing a methacrylate monomer group and a PV moiety was prepared via nucleophilic substitution between 2-chloroethyl methacrylate (CEMA) and penicillin V potassium (PVK). The PV-based PAC was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of the MAC with hydroxyethyl methacrylate (HEMA), and further characterized by (1)H NMR and gel permeation chromatography (GPC) analysis. Antibiotic resistance was investigated by passaging bacteria in low concentrations of the antibiotic for 19 days, followed by a 48-h challenge at higher concentrations. Our results suggest that the development of antibiotic resistance is unlikely. Zone of inhibition (ZOI) assays revealed no clearing zones around PV-containing resins indicating minimal antibiotic leakage from the material. Similarly, MTT assay demonstrated that the antibiotic-containing specimens did not release cytotoxic byproducts that may inhibit human gingival fibroblast growth. Counting of colony-forming units in an S. mutans biofilm model was used to assess bacterial survival at baseline and after subjecting the antibiotic-containing resin specimens to an enzymatic challenge for 30 days. Significantly reduced bacterial counts were observed as the biofilm aged from 24 to 72 h, and salivary enzymatic exposure did not reduce the antibacterial efficacy of the discs, suggesting that PV-resin will be effective in reducing the re-incidence of dental caries.

Rust diseases, although seasonal, have been severe constraints in wheat production in South Africa for almost 300 years. Rust research gained momentum with the institution of annual surveys in the 1980s, followed by race identification, an understanding of rust epidemiology, and eventually a focused collaboration amongst pathologists, breeders and geneticists. Diversity in South African populations of Puccinia triticina, P. graminis f. sp. tritici and P. striiformis f. sp. tritici has been described and isolates are available to accurately phenotype wheat germplasm and study pathogen populations at national, regional and global levels. Sources of resistance have been, and still are, methodically analysed and molecular marker systems were developed to incorporate, stack and verify complex resistance gene combinations in breeding lines and cultivars. Vigilance, capacity, new technologies, collaboration and sustained funding are critical for maintaining and improving the current research impetus for future management of these important diseases. Significance: Rust diseases threaten wheat crops worldwide, including in South Africa. Management of rusts includes regular surveillance, pathogen diversity studies, rigorous screening of wheat germplasm, and efficient breeding and selection for resistance. Collaboration among plant pathologists, geneticists and breeders has provided momentum in rust research and control in South Africa in recent years.

Extreme precipitation events are intensifying with increasing temperatures. However, observed extreme precipitation-temperature sensitivities have been found to vary significantly across the globe. Here we show that negative sensitivities found in previous studies are the result of limited consideration of within-day temperature variations due to precipitation. We find that short-duration extreme precipitation can be better described by subdaily atmospheric conditions before the start of storm events, resulting in positive sensitivities with increased consistency with the Clausius-Clapeyron relation across a wide range of climatic regions. Contrary to previous studies that advocate that dew point temperature drives precipitation, dry-bulb temperature is found to be a sufficient descriptor of precipitation variability. We argue that analysis methods for estimating extreme precipitation-temperature sensitivities should account for the strong and prolonged cooling effect of intense precipitation, as well as for the intermittent nature of precipitation.

To investigate whether dental adhesives modified with polyacrylic acid copper iodide particles could inhibit esterase activity in vitro and the copper release rate from resin matrices, as well as the correlation between the two variables.Different concentrations of copper iodide (0.1, 0.5 and 1.0 mg/ml) were incorporated into three commercially available adhesives representative of each type. Disk specimens (n = 3) were fabricated and incubated in cholesterol esterase and pseudo-cholinesterase solutions for 16 days (37°C, pH 7.0). The enzymatic activity and rate of copper release from resin matrices were evaluated at different 4, 8, 12, and 16 days with a UV/visible-light spectrophotometer.Increased copper release and reduced enzymatic activity were observed with higher concentrations of copper iodide (p0.001). Greater copper release with reduced enzymatic activity was also demonstrated at the earlier time periods with this relationship reversing over time (p0.001). A moderate negative correlation between the variables was evident (-0.441; p = 0.01).Adhesives containing copper iodide can inhibit esterase activity in a dose- and time-dependent manner. The correlation between the variables suggests that enzymatic activity may depend on the availability of copper.

The Australian wheat stem rust (Puccinia graminis f. sp. tritici) population was shaped by the introduction of four exotic incursions into the country. It was previously hypothesized that at least two of these (races 326-1,2,3,5,6 and 194-1,2,3,5,6 first detected in 1969) had an African origin and moved across the Indian Ocean to Australia on high-altitude winds. We provide strong supportive evidence for this hypothesis by combining genetic analyses and complex atmospheric dispersion modeling. Genetic analysis of 29 Australian and South African P. graminis f. sp. tritici races using microsatellite markers confirmed the close genetic relationship between the South African and Australian populations, thereby confirming previously described phenotypic similarities. Lagrangian particle dispersion model simulations using finely resolved meteorological data showed that long distance dispersal events between southern Africa and Australia are indeed possible, albeit rare. Simulated urediniospore transmission events were most frequent from central South Africa (viable spore transmission on approximately 7% of all simulated release days) compared with other potential source regions in southern Africa. The study acts as a warning of possible future P. graminis f. sp. tritici dispersal events from southern Africa to Australia, which could include members of the Ug99 race group, emphasizing the need for continued surveillance on both continents.

Affecting the vast majority of human beings, dental caries is a premier concern of worldwide dental health. As the most commonly used restorative material to treat dental caries, resin-based composites (RBCs) lack antibacterial properties leading to quite limited restoration lifetimes. The objective of this study is to develop a polymer-antibiotic conjugate (PAC) as an effective antibacterial additive for RBCs. A monomer-antibiotic conjugate (MAC) with significant solubility was prepared by an esterification reaction of tert-butyloxycarbonyl (Boc)-protected ciprofloxacin (Cip) and 2-hydroxyethyl methacrylate (HEMA). The Cip-containing PAC with well-controlled molecular weight and composition was synthesized by reversible addition-fragmentation chain transfer (RAFT) copolymerization of the MAC with HEMA (1 : 3 molar ratio), followed by the removal of Boc from the resulting copolymer. The antibacterial dental resin was then prepared by incorporating the PAC into a commercial resin, and their properties and antibacterial performance against Streptococcus mutans were tested. In vitro experiments revealed a very slow release of Cip, which resulted in significant killing effectiveness against Streptococcus mutans nonetheless, as observed through zone of inhibition assessment and SEM imaging. The promising antibacterial properties of these resins indicate that incorporating a PAC as an additive is a valid strategy to generate antibacterial materials for dental applications.

This study is a follow up investigation on recent work by our group demonstrating synthesis, release and strong antibacterial character of resins modified with penicillin V (PV)-based polymer-antibiotic conjugates (PACs). Here, we aimed to evaluate the mechanical, bonding, and other relevant biomedical properties of a commercial adhesive resin modified with PV-PAC. Single Bond Plus (SB+) was modified with PAC containing 1.8 wt% conjugated PV. Adhesive resins were bonded to dentin from extracted human molars and restorative resin added. Beams of cross-sectional area of 0.9 ± 0.1 mm (Kutsch and Young, 2011) (n = 20) were obtained from the molars and tested for micro-tensile bond strength (μTBS) at 24 h and 4 months. For cohesive strength, hourglass beams (10 × 2 × 1 mm; n = 10) were assessed for ultimate tensile strength (UTS), beam-shaped specimens (25×2×2 mm; n = 10) evaluated for flexural strength and modulus (FS/FM) via three-point bending, and cylindrical specimens (3 × 2 mm; n = 10) assessed for ultimate compressive strength (UCS). For surface micro-hardness (MH), cylindrical specimens (3 × 2 mm; n = 6) were assessed before and after an EtOH challenge. The degree of conversion (DC) (5 × 1 mm; n = 6) was determined based on changes in absorbance ratio between peaks at ~1637 cm(−1) and ~1608 cm(−1) before and after curing of adhesive resins using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. To monitor water uptake and diffusion kinetics over a 28-day period, specimens (5 × 1mm) were desiccated, weighed and stored in deionized water. Control and PV-PAC modified adhesive resins demonstrated similar μTBS at 24 h and 4 months; both showing decrease in values after 4 months (p = 0.001 and 0.004). No significant differences between adhesive resins were shown in UTS, FS/FM or UCS (p

Race 2SA55 of the wheat stem rust pathogen, Puccinia graminis f. sp. tritici, was described for the first time during 2000 in South Africa. This race is of particular interest as it was the first local report of increased virulence towards barley cultivars by wheat stem rust. Using three original accessions of 2SA55 from the rust collection of the University of the Free State, nine single pustule isolates were established. Phenotyping of isolates to characterise 2SA55 according to the North American nomenclature system revealed variation in virulence for Sr9g on the tester lines Kubanka and Acme, which was not detected in the initial description of 2SA55. Seven isolates coded as BNGSC, which except for virulence on Sr9b resembled the initial avirulence/virulence description for 2SA55. The remaining two isolates with Sr9g virulence coded as BPGSC. The seedling infection types for the two 2SA55 derived races BNGSC and BPGSC on the Stakman differential set as well as on an extended set of Sr lines and 144 South African wheat cultivars and advanced breeding lines revealed no further distinction in reaction between them. Microsatellite analysis indicated that while race BN/PGSC shares phenotypic similarity with several of the South African non-Ug99 races, it was genetically distinct.

Virulence analysis of the South African Puccinia triticina Eriks. population from 2012 to 2016 revealed the presence of four new wheat (Triticum aestivum L.) leaf rust races, which coincided with the increased incidence of the disease during this period. Considering their infection types on 43 differential wheat entries, three of the new races namely 3SA10 (North American code CFPS), 3SA38 (CDPS) and 3SA248 (CFPS) were found to be similar to each other, and only varied in virulence for Lr20 and Lr26 whereas race 3SA115 (CBPS) was more avirulent. This was confirmed when seedling infection type data for 117 South African wheat cultivars and advanced breeding lines revealed that only 35 of the entries are susceptible to race 3SA115. Races 3SA10 (77 entries susceptible), 3SA38 (68) and 3SA248 (78) showed increased virulence when compared with the 51 entries susceptible to race 3SA145 (CCPS) which dominated in frequency during 2012 to 2016. SSR analysis confirmed the close genetic relationships between the four new races and race 3SA145. The results verified the adaptability of the leaf rust pathogen and by acquiring virulence for Lr24, the new races 3SA10, 3SA38 and 3SA248 are considered to become more prevalent and threatening compared to the current dominating race 3SA145.

Objective To investigate the effect of poly-acrylic acid (PAA) copper iodide (CuI) adhesives on bond degradation, tensile strength, and biocompatibility. Methods PAA-CuI particles were incorporated into Optibond XTR, Optibond Solo and XP Bond in 0.1 and 0.5 mg/ml. Clearfil SE Protect, an MDPB-containing adhesive, was used as control. The adhesives were applied to human dentin, polymerized and restored with composite in 2 mm-increments. Resin–dentin beams (0.9 ± 0.1 mm 2 ) were evaluated for micro-tensile bond strength after 24 h, 6 months and 1 year. Hourglass specimens (10 × 2 × 1 mm) were evaluated for ultimate tensile strength (UTS). Cell metabolic function of human gingival fibroblast cells exposed to adhesive discs (8 × 1 mm) was assessed with MTT assay. Copper release from adhesive discs (5 × 1 mm) was evaluated with UV–vis spectrophotometer after immersion in 0.9% NaCl for 1, 3, 5, 7, 10, 14, 21 and 30 days. SEM, EDX and XRF were conducted for microstructure characterization. Results XTR and Solo did not show degradation when modified with PAA-CuI regardless of the concentration. The UTS for adhesives containing PAA-CuI remained unaltered relative to the controls. The percent viable cells were reduced for Solo 0.5 mg/ml and XP 0.1 or 0.5 mg/ml PAA-CuI. XP demonstrated the highest ion release. For all groups, the highest release was observed at days 1 and 14. Significance PAA-CuI particles prevented the bond degradation of XTR and Solo after 1 year without an effect on the UTS for any adhesive. Cell viability was affected for some adhesives. A similar pattern of copper release was demonstrated for all adhesives.

Treponema denticola is an oral spirochete strongly associated with severe periodontal disease. A prominent virulence factor, the major outer sheath protein (Msp), disorients neutrophil chemotaxis by altering the cellular phosphoinositide balance, leading to impairment of downstream chemotactic events including actin rearrangement, Rac1 activation, and Akt activation in response to chemoattractant stimulation. The specific regions of Msp responsible for interactions with neutrophils remain unknown. In this study, we investigated the inhibitory effect of truncated Msp regions on neutrophil chemotaxis and associated signaling pathways. Murine neutrophils were treated with recombinant protein truncations followed by assessment of chemotaxis and associated signal pathway activation. Chemotaxis assays indicate sequences within the C-terminal region; particularly the first 130 amino acids, have the strongest inhibitory effect on neutrophil chemotaxis. Neutrophils incubated with the C-terminal region protein also demonstrated the greatest inhibition of Rac1 activation, increased phosphoinositide phosphatase activity, and decreased Akt activation; orchestrating impairment of chemotaxis. Furthermore, incubation with antibodies specific to only the C-terminal region blocked the Msp-induced inhibition of chemotaxis and denaturing the protein restored Rac1 activation. Msp from the strain OTK, with numerous amino acid substitutions throughout the polypeptide, including the C-terminal region compared with strain 35405, showed increased ability to impair neutrophil chemotaxis. Collectively, these results indicate that the C-terminal region of Msp is the most potent region to modulate neutrophil chemotactic signaling and that specific sequences and structures are likely to be required. Knowledge of how spirochetes dampen the neutrophil response is limited and Msp may represent a novel therapeutic target for periodontal disease.

Oncostatin M (OSM) is a pleiotropic cytokine elevated in a number of inflammatory conditions including periodontal disease. OSM is produced by a variety of immune cells and has diverse functionality such as regulation of metabolic processes, cell differentiation, and the inflammatory response to bacterial pathogens. The oral cavity is under constant immune surveillance including complementary neutrophil and macrophage populations, due to a persistent symbiotic bacterial presence. Periodontal disease is characterized by a dysbiotic bacterial community, with an abundance of Treponema denticola. Despite strong associations with severe periodontal disease, the source and mechanism of the release of OSM have not been defined in the oral cavity. We show that OSM protein is elevated in the gingival epithelium and immune cell infiltrate during periodontal disease. Furthermore, salivary and oral neutrophil OSM is elevated in correlation with the presence of T. denticola. In an air pouch infection model, T. denticola stimulated higher levels of OSM than the oral pathogen Porphorymonas gingivalis, despite differential recruitment of innate immune cells suggesting T. denticola has distinct properties to elevate OSM levels. OSM release and transcription were increased in isolated human blood, oral neutrophils, or macrophages exposed to T. denticola in vitro as measured by ELISA, qPCR, and microscopy. Using transcription, translation, and actin polymerization inhibition, we found that T. denticola stimulates both OSM release through degranulation and de novo synthesis in neutrophils and also OSM release and synthesis in macrophages. Differential induction of OSM by T. denticola may promote clinical periodontal disease.

Additional file 1. COREQ checklist.

Additional file 2. Interveiw guide.