Silver ions disrupt K+ homeostasis and cellular integrity in intact barley (Hordeum vulgare L.) roots

The heavy metals silver, gold, and mercury can strongly inhibit aquaporin-mediated water flow across plant cell membranes, but critical examinations of their side effects are rare. Here, the short-lived radiotracer 42K is used to demonstrate that these metals, especially silver, profoundly change potassium homeostasis in roots of intact barley (Hordeum vulgare L.) plants, by altering unidirectional K+ fluxes. Doses as low as 5 μM AgNO3 rapidly reduced K+ influx to 5% that of controls, and brought about pronounced and immediate increases in K+ efflux, while higher doses of Au3+ and Hg2+ were required to produce similar responses. Reduced influx and enhanced efflux of K+ resulted in a net loss of >40% of root tissue K+ during a 15 min application of 500 μM AgNO3, comprising the entire cytosolic potassium pool and about a third of the vacuolar pool. Silver also brought about major losses of UV-absorbing compounds, total electrolytes, and NH4+. Co-application, with silver, of the channel blockers Cs+, TEA+, or Ca2+, did not affect the enhanced efflux, ruling out the involvement of outwardly rectifying ion channels. Taken together with an examination of propidium iodide staining under confocal microscopy, the results indicate that silver ions affect K+ homeostasis by directly inhibiting K+ influx at lower concentrations, and indirectly inhibiting K+ influx and enhancing K+ efflux, via membrane destruction, at higher concentrations. Ni2+, Cd2+, and Pb2+, three heavy metals not generally known to affect aquaporins, did not enhance K+ efflux or cause propidium iodide incorporation. The study reveals strong and previously unknown effects of major aquaporin inhibitors and recommends caution in their application

Maintenance of Physical Activity Behavior by Individuals with Prediabetes and Diabetes during the COVID-19 Pandemic after Completing an Exercise Intervention in Brazil

This cross-sectional study evaluated the perception of individuals with prediabetes/diabetes about their living conditions during the COVID-19 pandemic to identify the facilitators, barriers, and reasons to remain physically active at home and adhere to recommended exercise. It included individuals with prediabetes/diabetes who had completed an exercise intervention, which started on-site and moved to a remote home-based regime due to the COVID-19 pandemic and were advised to keep exercising at home. The outcomes were assessed by a bespoke questionnaire that was developed by the research team, the Brazilian Portuguese adapted version of the Exercise Adherence Rating scale, and the Motives for Physical Activity Measure-Revised scale. Of 15 participants (8 female, 58 ± 11 years), most reported positive perceptions about their living conditions and few difficulties maintaining some physical activity at home. However, only 53.8% of them adhered to the recommended exercise. Time flexibility, no need for commuting, and a sense of autonomy were the main facilitators of home exercise, while a lack of adequate space was the main barrier. The descending order of median scores that were obtained in each reason for physical activity was fitness, enjoyment, competence, social, and appearance. Individuals with prediabetes/diabetes maintained some physical activity during the pandemic, mainly motivated by health concerns

Analyticity and the Holographic S-Matrix

We derive a simple relation between the Mellin amplitude for AdS/CFT correlation functions and the bulk S-Matrix in the flat spacetime limit, proving a conjecture of Penedones. As a consequence of the Operator Product Expansion, the Mellin amplitude for any unitary CFT must be a meromorphic function with simple poles on the real axis. This provides a powerful and suggestive handle on the locality vis-a-vis analyticity properties of the S-Matrix. We begin to explore analyticity by showing how the familiar poles and branch cuts of scattering amplitudes arise from the holographic description. For this purpose we compute examples of Mellin amplitudes corresponding to 1-loop and 2-loop Witten diagrams in AdS. We also examine the flat spacetime limit of conformal blocks, implicitly relating the S-Matrix program to the Bootstrap program for CFTs. We use this connection to show how the existence of small black holes in AdS leads to a universal prediction for the conformal block decomposition of the dual CFT.Comment: 28+15 pages, 7 figures; v2: typos correcte

Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Usefulness of PCR-based assays to assess drug efficacy in Chagas disease chemotherapy: value and limitations

One major goal of research on Chagas disease is the development of effective chemotherapy to eliminate the infection from individuals who have not yet developed cardiac and/or digestive disease manifestations. Cure evaluation is the more complex aspect of its treatment, often leading to diverse and controversial results. The absence of reliable methods or a diagnostic gold standard to assess etiologic treatment efficacy still constitutes a major challenge. In an effort to develop more sensitive tools, polymerase chain reaction (PCR)-based assays were introduced to detect low amounts of Trypanosoma cruzi DNA in blood samples from chagasic patients, thus improving the diagnosis and follow-up evaluation after chemotherapy. In this article, I review the main problems concerning drug efficacy and criteria used for cure estimation in treated chagasic patients, and the work conducted by different groups on developing PCR methodologies to monitor treatment outcome of congenital infections as well as recent and late chronic T. cruzi infections

Intravenous antibiotics for pulmonary exacerbations in people with cystic fibrosis

BACKGROUND: Cystic fibrosis is a multi-system disease characterised by the production of thick secretions causing recurrent pulmonary infection, often with unusual bacteria. Intravenous antibiotics are commonly used in the treatment of acute deteriorations in symptoms (pulmonary exacerbations); however, recently the assumption that exacerbations are due to increases in bacterial burden has been questioned. OBJECTIVES: To establish if intravenous antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis improve short- and long-term clinical outcomes. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews and ongoing trials registers.Date of last search of Cochrane trials register: 27 July 2015. SELECTION CRITERIA: Randomised controlled trials and the first treatment cycle of cross-over studies comparing intravenous antibiotics (given alone or in an antibiotic combination) with placebo, inhaled or oral antibiotics for people with cystic fibrosis experiencing a pulmonary exacerbation. DATA COLLECTION AND ANALYSIS: The authors assessed studies for eligibility and risk of bias and extracted data. MAIN RESULTS: We included 40 studies involving 1717 participants. The quality of the included studies was largely poor and, with a few exceptions, these comprised of mainly small, inadequately reported studies.When comparing treatment with a single antibiotic to a combined antibiotic regimen, those participants receiving a combination of antibiotics experienced a greater improvement in lung function when considered as a whole group across a number of different measurements of lung function, but with very low quality evidence. When limited to the four placebo-controlled studies (n = 214), no difference was observed, again with very low quality evidence. With regard to the review's remaining primary outcomes, there was no effect upon time to next exacerbation and no studies in any comparison reported on quality of life. There were no effects on the secondary outcomes weight or adverse effects. When comparing specific antibiotic combinations there were no significant differences between groups on any measure. In the comparisons between intravenous and nebulised antibiotic or oral antibiotic (low quality evidence), there were no significant differences between groups on any measure. No studies in any comparison reported on quality of life. AUTHORS' CONCLUSIONS: The quality of evidence comparing intravenous antibiotics with placebo is poor. No specific antibiotic combination can be considered to be superior to any other, and neither is there evidence showing that the intravenous route is superior to the inhaled or oral routes. There remains a need to understand host-bacteria interactions and in particular to understand why many people fail to fully respond to treatment

Intimate Partner Violence and Health Care-Seeking Patterns Among Female Users of Urban Adolescent Clinics

To assess the prevalence of intimate partner violence (IPV) and associations with health care-seeking patterns among female patients of adolescent clinics, and to examine screening for IPV and IPV disclosure patterns within these clinics. A self-administered, anonymous, computerized survey was administered to female clients ages 14–20 years (N = 448) seeking care in five urban adolescent clinics, inquiring about IPV history, reasons for seeking care, and IPV screening by and IPV disclosure to providers. Two in five (40%) female urban adolescent clinic patients had experienced IPV, with 32% reporting physical and 21% reporting sexual victimization. Among IPV survivors, 45% reported abuse in their current or most recent relationship. IPV prevalence was equally high among those visiting clinics for reproductive health concerns as among those seeking care for other reasons. IPV victimization was associated with both poor current health status (AOR 1.57, 95% CI 1.03–2.40) and having foregone care in the past year (AOR 2.59, 95% CI 1.20–5.58). Recent IPV victimization was associated only with past 12 month foregone care (AOR 2.02, 95% CI 1.18–3.46). A minority (30%) reported ever being screened for IPV in a clinical setting. IPV victimization is pervasive among female adolescent clinic attendees regardless of visit type, yet IPV screening by providers appears low. Patients reporting poor health status and foregone care are more likely to have experienced IPV. IPV screening and interventions tailored for female patients of adolescent clinics are needed