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Kcv channels from plant viruses represent the autonomous pore module of potassium channels, devoid of any regulatory domains. These small proteins show very reproducible single-channel behavior in planar lipid bilayers. Thus, they are an optimum system for the study of the biophysics of ion transport and gating. Structural models based on homology modeling have been used successfully, but experimental structural data are currently not available. Here we determine the size of the cytosolic pore entrance by studying the blocker kinetics. Blocker binding and dissociation rate constants ranging from 0.01 to 1000 ms -1 were determined for different quaternary ammonium ions. We found that the cytosolic pore entrance of Kcv NTS must be at least 11 Å wide. The results further indicate that the residues controlling a cytosolic gate in one of the Kcv isoforms influence blocker binding/dissociation as well as a second gate even when the cytosolic gate is in the open state. The voltage dependence of the rate constant of blocker release is used to test, which blockers bind to the same binding site.

Plants have been affected by water stress ever since they settled on dry land. In severe and persisting drought, plant leaves are wilting. However, a documentation at the anatomical level of the minute changes that occur before wilting is challenging. On the other hand, understanding the anatomical alteration in plant leaves with respect to water stress provides a stronger basis to study molecular and submolecular processes through which plants enhance drought tolerance. In this work, we applied an affordable method to visualise mesophyll layers of Arabidopsis thaliana cell lines without preparation steps that would alter the volume of the cells. We rapidly plunge-froze the leaves in liquid nitrogen, cut them while in the N 2 bath, and immediately imaged the mesophyll cross sections in a scanning electron microscope. We applied a reduction of watering from 60 to 40 to 20 mL per day and investigated two time points, 7 and 12 days, respectively. Interestingly, the overall thickness of leaves increased in water stress conditions. Our results showed that the palisade and spongy layers behaved differently under varying watering regimes. Moreover, the results showed that this method can be used to image leaf sections after drought stress without the risk of artefacts or swelling caused by contact to liquids as during chemical fixation., (© 2024 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.)

Most potassium channels have two main gate locations, hosting an inner gate at the cytosolic entrance and a filter gate in the selectivity filter; the function of these gates is in many channels coupled. To obtain exclusive insights into the molecular mechanisms that determine opening and closing of the filter gate, we use a combination of single-channel recordings and gating analysis in the minimal viral channel Kcv NTS . This channel has no inner gate, and its fast closing at negative voltages can therefore be entirely assigned to the filter gate. We find that mutations of S42 in the pore helix severely slow down closing of this filter gate, an effect which is not correlated with hydrogen bond formation by the amino acid at this position. Hence, different from KcsA, which contains the critical E71 in the equivalent position forming a salt bridge, the coupling between selectivity filter and surrounding structures for filter gating must in Kcv NTS rely on different modes of interaction. Quantitative analysis of concatemers carrying different numbers of S42T mutations reveals that each subunit contributes the same amount of ∼ 0.4 kcal/mol to the energy barrier for filter closure indicating a concerted action of the subunits. Since the mutations have neither an influence on the unitary current nor on the voltage dependency of the gate, the data stress that the high subunit cooperativity is mediated through conformational changes rather than through changes in the ion occupation in the selectivity filter., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Many regulatory circuits in plants contain steps of targeted proteolysis, with the ubiquitin proteasome system (UPS) as the mediator of these proteolytic events. In order to decrease ubiquitin-dependent proteolysis, we inducibly expressed a ubiquitin variant with Arg at position 48 instead of Lys (ubK48R). This variant acts as an inhibitor of proteolysis via the UPS, and allowed us to uncover processes that are particularly sensitive to UPS perturbation., Results: Expression of ubK48R during germination leads to seedling death. We analyzed the seedling transcriptome, proteome and metabolome 24 h post ubK48R induction and confirmed defects in chloroplast development. We found that mutations in single genes can suppress seedling lethality, indicating that a single process in seedlings is critically sensitive to decreased performance of the UPS. Suppressor mutations in phototropin 2 (PHOT2) suggest that a contribution of PHOT2 to chloroplast protection is compromised by proteolysis inhibition., Conclusions: Overall, the results reveal protein turnover as an integral part of a signal transduction chain that protects chloroplasts during development., (© 2022. The Author(s).)

Ehrlichiosis has been infrequently described as transmissible through organ transplantation. Two donor-derived clusters of ehrlichiosis are described here. During the summer of 2020, 2 cases of ehrlichiosis were reported to the Organ Procurement and Transplantation Network (OPTN) and the Centers for Disease Control and Prevention (CDC) for investigation. Additional transplant centers were contacted to investigate similar illness in other recipients and samples were sent to the CDC. Two kidney recipients from a common donor developed fatal ehrlichiosis-induced hemophagocytic lymphocytic histiocytosis. Two kidney recipients and a liver recipient from another common donor developed ehrlichiosis. All 3 were successfully treated. Clinicians should consider donor-derived ehrlichiosis when evaluating recipients with fever early after transplantation after more common causes are ruled out, especially if the donor has epidemiological risk factors for infection. Suspected cases should be reported to the organ procurement organization and the OPTN for further investigation by public health authorities., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

In 2019, a novel coronavirus was identified in Wuhan, China. This strain was classified as a pandemic in early 2020 by the World Health Organization (WHO), rapidly reaching millions of cases worldwide and overwhelming intensive care units. One distinct feature identified in severe SARS-CoV-2 is abnormal and complex coagulation and hematologic abnormalities, including significantly elevated D-dimer and fibrin/fibrinogen values possibly increasing morbidity and mortality in this patient population. Aggressive anticoagulation therapy with appropriate peak anti-Xa level monitoring has produce satisfactory results at our institution. Our intent is to present a case series of our strategy to highlight the benefits of this approach., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2020.)

Modulating the activity of ion channels by blockers yields information on both the mode of drug action and on the biophysics of ion transport. Here we investigate the interplay between ions in the selectivity filter (SF) of K + channels and the release kinetics of the blocker tetrapropylammonium in the model channel Kcv NTS . A quantitative expression calculates blocker release rate constants directly from voltage-dependent ion occupation probabilities in the SF. The latter are obtained by a kinetic model of single-channel currents recorded in the absence of the blocker. The resulting model contains only two adjustable parameters of ion-blocker interaction and holds for both symmetric and asymmetric ionic conditions. This data-derived model is corroborated by 3D reference interaction site model (3D RISM) calculations on several model systems, which show that the K + occupation probability is unaffected by the blocker, a direct consequence of the strength of the ion-carbonyl attraction in the SF, independent of the specific protein background. Hence, Kcv NTS channel blocker release kinetics can be reduced to a small number of system-specific parameters. The pore-independent asymmetric interplay between K + and blocker ions potentially allows for generalizing these results to similar potassium channels., 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 © 2021 Gabriel, Hansen, Urban, Drexler, Winterstein, Rauh, Thiel, Kast and Schroeder.)

In this proof-of-principle study, we established and implemented a cross-modality imaging (CMI) pipeline to characterize and compare bisphosphonate (BIS)-treated jawbones of Sprague-Dawley rats after tooth extraction after physical therapies (photobiomodulation and extracorporeal shockwave therapy (PBMT and ESWT)). We showcase the feasibility of such a CMI approach and its compatibility across imaging modalities to probe the same region of interest (ROI) of the same jawbone. Jawbones were imaged in toto in 3D using micro-Computed Tomography to identify ROIs for subsequent sequential 2D analysis using well-established technologies such as Atomic Force Microscopy and Scanning Electron Microscopy, and recent imaging approaches in biomedical settings, such as micro-X-Ray Fluorescence Spectroscopy. By combining these four modalities, multiscale information on the morphology, topography, mechanical stiffness (Young's modulus), and calcium, zinc and phosphorus concentrations of the bone was collected. Based on the CMI pipeline, we characterized and compared the jawbones of a previously published clinically relevant rat model of BIS-related osteonecrosis of the jawbone (BRONJ) before and after treatment with BISs, PBMT and ESWT. While we did not find that physical therapies altered the mechanical and elemental jawbone parameters with significance (probably due to the small sample size of only up to 5 samples per group), both ESWT and PBMT reduced pore thicknesses and bone-to-enamel distances significantly compared to the controls. Although focused on BIS-treated jawbones, the established CMI platform can be beneficial in the study of bone-related diseases in general (such as osteoarthritis or -porosis) to acquire complementary hallmarks and better characterize disease status and alleviation potentials.

Background: Rocky Mountain spotted fever (RMSF) is a significant public health problem in Sonora, Mexico, resulting in thousands of cases and hundreds of deaths. Outbreaks of RMSF are perpetuated by heavy brown dog tick infestations in and around homes. During 2009-2015, there were 61 RMSF cases and 23 deaths in a single community of Sonora (Community A)., Methods: An integrated intervention was carried out from March-November 2016 aimed at reducing tick populations with long-acting acaricidal collars on dogs, environmental acaricides applied to peri-domestic areas and RMSF education. Tick levels were measured by inspection of community dogs to monitor efficacy of the intervention. A similar neighborhood (Community B) was selected for comparison and received standard care (acaricide treatment and education)., Results: The prevalence of tick-infested dogs in Community A declined from 32.5% to 8.8% (p<0.01). No new cases of RMSF were identified in this area during the subsequent 18 mo. By comparison, the percentage of tick-infested dogs in Community B decreased from 19% to 13.4% (p=0.36) and two cases were reported, including one death., Conclusions: Community-based interventions using an integrated approach to control brown dog ticks can diminish the morbidity and mortality attributable to RMSF., (© The Author(s) 2019. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

Rocky Mountain spotted fever (RMSF), a life-threatening tickborne zoonosis caused by Rickettsia rickettsii, is a reemerging disease in Mexico (1,2). R. rickettsii is an intracellular bacterium that infects vascular endothelium and can cause multisystem organ failure and death in the absence of timely administration of a tetracycline-class antibiotic, typically doxycycline. Epidemic RMSF, as described in parts of Arizona and Mexico, is associated with massive local infestations of the brown dog tick (Rhiphicephalus sanguineus sensu lato) on domestic dogs and in peridomestic settings that result in high rates of human exposure; for example, during 2003-2012, in Arizona the incidence of RMSF in the three most highly affected communities was 150 times the U.S. national average (3,4). In 2015, the Mexico Ministry of Health (MOH) declared an epidemiologic emergency because of high and sustained rates of RMSF in several states in northern Mexico, including the state of Sonora. During 2004-2015, a total of 1,129 cases and 188 RMSF deaths were reported from Sonora (Sonora MOH, unpublished data, 2016). During 2009-2015, one impoverished community (community A) in Sonora reported 56 cases of RMSF involving children and adolescents, with a case-fatality rate of 40% (Sonora MOH, unpublished data, 2016). Poverty and lack of timely access to health services are risk factors for severe RMSF. Children are especially vulnerable to infection, because they might have increased contact with dogs and spend more time playing around spaces where ticks survive (5). In Sonora, case fatality rates for children aged <10 years can be as high as 30%, which is almost four times the aggregate case-fatality rate reported for the general population of the state (8%) (2), and 10-13 times higher than the case-fatality rate described for this age group in the United States (2.4%) (6).

Rocky Mountain spotted fever (RMSF) transmitted by the brown dog tick (Rhipicephalus sanguineus sensu lato) has emerged as a significant public health risk on American Indian reservations in eastern Arizona. During 2003-2012, more than 250 RMSF cases and 19 deaths were documented among Arizona's American Indian population. The high case fatality rate makes community-level interventions aimed at rapid and sustained reduction of ticks urgent. Beginning in 2012, a two year pilot integrated tick prevention campaign called the RMSF Rodeo was launched in a ∼ 600-home tribal community with high rates of RMSF. During year one, long-acting tick collars were placed on all dogs in the community, environmental acaricides were applied to yards monthly, and animal care practices such as spay and neuter and proper tethering procedures were encouraged. Tick levels, indicated by visible inspection of dogs, tick traps and homeowner reports were used to monitor tick presence and evaluate the efficacy of interventions throughout the project. By the end of year one, <1% of dogs in the RMSF Rodeo community had visible tick infestations five months after the project was started, compared to 64% of dogs in Non-Rodeo communities, and environmental tick levels were reduced below detectable levels. The second year of the project focused on use of the long-acting collar alone and achieved sustained tick control with fewer than 3% of dogs in the RMSF Rodeo community with visible tick infestations by the end of the second year. Homeowner reports of tick activity in the domestic and peridomestic setting showed similar decreases in tick activity compared to the non-project communities. Expansion of this successful project to other areas with Rhipicephalus-transmitted RMSF has the potential to reduce brown dog tick infestations and save human lives.

In order to eliminate Lymphatic Filariasis (LF) as a public health problem, the World Health Assembly recommends an approach which includes interruption of transmission of infection and the alleviation of morbidity. In 2000, the Togolese National Program to Eliminate Lymphatic Filariasis (PNELF) started the annual mass drug administrations and in 2007, the program added a morbidity component for the management of lymphedema. This manuscript describes the methods of an evaluation aimed at assessing the strengths and weaknesses of the Togolese National Lymphedema Morbidity Program. The evaluation was conducted through in-depth interviews with stakeholders at each programmatic level. Interviews focused on message dissemination, health provider training, patient self-care practices, social dynamics, and program impact. The evaluation demonstrated that the program strengths include the standardization and in-depth training of health staff, dissemination of the program's treatment message, a positive change in the community's perception of lymphedema, and successful patient recruitment and training in care techniques. The lessons learned from this evaluation helped to improve Togo's program, but may also provide guidance and strategies for other countries desiring to develop a morbidity program. The methods of program evaluation described in this paper can serve as a model for monitoring components of other decentralized national health programs in low resource settings., (Copyright © 2013. Published by Elsevier Ltd.)

Context: Since its launch in 2001, Wikipedia has become the most popular general reference site on the Internet and a popular source of health care information. To evaluate the accuracy of this resource, the authors compared Wikipedia articles on the most costly medical conditions with standard, evidence-based, peer-reviewed sources., Methods: The top 10 most costly conditions in terms of public and private expenditure in the United States were identified, and a Wikipedia article corresponding to each topic was chosen. In a blinded process, 2 randomly assigned investigators independently reviewed each article and identified all assertions (ie, implication or statement of fact) made in it. The reviewer then conducted a literature search to determine whether each assertion was supported by evidence. The assertions found by each reviewer were compared and analyzed to determine whether assertions made by Wikipedia for these conditions were supported by peer-reviewed sources., Results: For commonly identified assertions, there was statistically significant discordance between 9 of the 10 selected Wikipedia articles (coronary artery disease, lung cancer, major depressive disorder, osteoarthritis, chronic obstructive pulmonary disease, hypertension, diabetes mellitus, back pain, and hyperlipidemia) and their corresponding peer-reviewed sources (P<.05) and for all assertions made by Wikipedia for these medical conditions (P<.05 for all 9)., Conclusion: Most Wikipedia articles representing the 10 most costly medical conditions in the United States contain many errors when checked against standard peer-reviewed sources. Caution should be used when using Wikipedia to answer questions regarding patient care.

Currently, a 30-cluster survey to monitor drug coverage after mass drug administration for neglected tropical diseases is the most common methodology used by control programs. We investigated alternative survey methodologies that could potentially provide an estimation of drug coverage. Three alternative survey methods (market, village chief, and religious leader) were conducted and compared to the 30-cluster method in Malawi, Mali, and Uganda. In Malawi, drug coverage for the 30-cluster, market, village chief, and religious leader methods were 66.8% (95% CI 60.3-73.4), 74.3%, 76.3%, and 77.8%, respectively. In Mali, results for round 1 were 62.6% (95% CI 54.4-70.7), 56.1%, 74.8%, and 83.2%, and 57.2% (95% CI 49.0-65.4), 54.5%, 72.2%, and 73.3%, respectively, for round 2. Uganda survey results were 65.7% (59.4-72.0), 43.7%, 67.2%, and 77.6% respectively. Further research is needed to test different coverage survey methodologies to determine which survey methods are the most scientifically rigorous and resource efficient., (Published by Elsevier B.V.)

Lymphatic filariasis (LF) is a vector-borne parasitic disease that can clinically manifest as disabling lymphedema. Although the LF elimination program aims to reduce disability and to interrupt transmission, there has been a scarcity of disease morbidity management programs, particularly on a national scale. This report describes the implementation of the first nationwide LF lymphedema management program. The program, which was initiated in Togo in 2007, focuses on patient behavioral change. Its goal is two-fold: to achieve a sustainable program on a national-scale, and to serve as a model for other countries. The program has five major components: 1) train at least one health staff in lymphedema care in each health facility in Togo; 2) inform people with a swollen leg that care is available at their dispensary; 3) train patients on self-care; 4) provide a support system to motivate patients to continue self-care by training community health workers or family members and providing in home follow-up; and 5) integrate lymphedema management into the curriculum for medical staff. The program achieved the inclusion of lymphedema management in the routine healthcare package. The evaluation after three years estimated that 79% of persons with a swollen leg in Togo were enrolled in the program. The adherence rate to the proposed World Health Organization treatment of washing, exercise, and leg elevation was more than 70% after three years of the program, resulting in a stabilization of the lymphedema stage and a slight decrease in reported acute attacks among program participants. Health staff and patients consider the program successful in reaching and educating the patients. After the external funding ended, the morbidity management program is maintained through routine Ministry of Health activities.

To eliminate Lymphatic filariasis (LF) as a public health problem, the World Health Organization (WHO) recommends that any area with infection prevalence greater than or equal to 1% (denoted by presence of microfilaremia or antigenemia) should receive mass drug administration (MDA) of antifilarial drugs for at least five consecutive rounds. Areas of low-antigen prevalence (< 1%) are thought to pose little risk for continued transmission of LF. Five low-antigen prevalence communes in Haiti, characterized as part of a national survey, were further assessed for transmission in this study. An initial evaluation of schoolchildren was performed in each commune to identify antigen-positive children who served as index cases for subsequent community surveys conducted among households neighboring the index cases. Global positioning system (GPS) coordinates and immunochromatographic tests (ICT) for filarial antigenemia were collected on approximately 1,600 persons of all ages in the five communes. The relationship between antigen-positive cases in the community and distance from index cases was evaluated using multivariate regression techniques and analyses of spatial clustering. Community surveys demonstrated higher antigen prevalence in three of the five communes than was observed in the original mapping survey; autochthonous cases were found in the same three communes. Regression techniques identified a significantly increased likelihood of being antigen-positive when living within 20 meters of index cases when controlling for age, gender, and commune. Spatial clustering of antigen-positive cases was observed in some, but not all communes. Our results suggest that localized transmission was present even in low-prevalence settings and suggest that better surveillance methods may be needed to detect microfoci of LF transmission.