Antimicrobial activity of the fiber produced by “pochote” Ceiba aesculifolia subsp. parvifolia

Background: The cotton-like fiber from the fruit of Pochote (Ceiba aesculifolia subsp. parvifolia) can be applied to wounds for healing purposes. As microorganisms can infect wounds and hamper the wound healing process, the aim of this study was to determine the antimicrobial activity and chemical composition of the methanolic extract of Pochote fiber.Materials and Methods: The methanolic extract was tested against bacteria and fungi. For bacteria, the Kirby-Baüer disc diffusion and broth dilution methods were employed to determine the MIC and MBC. In addition, bactericidal kinetic curves were generated. The antifungal activity was determined by the radial diffusion method. The antioxidant activity, total phenolic content, and the flavonoid content were determined. Bioassay guided fractionation was also performed.Results: The methanolic extract showed activity against Enterococcus faecalis, Staphylococcus aureus and Vibrio cholerae (cc). The tested V. cholerae strains were the most sensitive strains, and exhibited a clear CFU size reduction from the bactericidal kinetic curves. The methanolic extract had activity against T. mentagrophytes and R. lilacina. The antioxidant activity (SC50= 36.42 μg/mL) was related to the total phenolic (74.4 mg eAG/g) and flavonoid content (21.982 mg (eQ)/g). The bioassay guided fractionation results suggested that the antimicrobial properties of the extract may act through synergism because the total extract had higher activity against bacteria compared to the collected fractions.Conclusion: This study scientifically validates the application of the fruit fiber from Pochote as a part of a traditional medicine approach to alleviate infections caused by bacteria and fungi.Keywords: antimicrobial, Ceiba, Bombacaceae, fruit fib

Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism.

Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells

Sexual Size Dimorphism and Body Condition in the Australasian Gannet

Funding: The research was financially supported by the Holsworth Wildlife Research Endowment. Acknowledgments We thank the Victorian Marine Science Consortium, Sea All Dolphin Swim, Parks Victoria, and the Point Danger Management Committee for logistical support. We are grateful for the assistance of the many field volunteers involved in the study.Peer reviewedPublisher PD

Genetic Isolation between the Western and Eastern Pacific Populations of Pronghorn Spiny Lobster Panulirus penicillatus

The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142–1,207 bp) and 16S rDNA (535–546 bp) regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP)(Galápagos Islands and its adjacent water), Central Pacific (CP)(Hawaii and Tuamotu) and the Western Pacific (WP)(Japan, Indonesia, Fiji, New Caledonia and Australia). Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP). No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance) between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific), with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY)

Cubic exact solutions for the estimation of pairwise haplotype frequencies: implications for linkage disequilibrium analyses and a web tool 'CubeX'

<p>Abstract</p> <p>Background</p> <p>The frequency of a haplotype comprising one allele at each of two loci can be expressed as a cubic equation (the 'Hill equation'), the solution of which gives that frequency. Most haplotype and linkage disequilibrium analysis programs use iteration-based algorithms which substitute an estimate of haplotype frequency into the equation, producing a new estimate which is repeatedly fed back into the equation until the values converge to a maximum likelihood estimate (expectation-maximisation).</p> <p>Results</p> <p>We present a program, "CubeX", which calculates the biologically possible exact solution(s) and provides estimated haplotype frequencies, D', r²and <it>χ</it>²values for each. CubeX provides a "complete" analysis of haplotype frequencies and linkage disequilibrium for a pair of biallelic markers under situations where sampling variation and genotyping errors distort sample Hardy-Weinberg equilibrium, potentially causing more than one biologically possible solution. We also present an analysis of simulations and real data using the algebraically exact solution, which indicates that under perfect sample Hardy-Weinberg equilibrium there is only one biologically possible solution, but that under other conditions there may be more.</p> <p>Conclusion</p> <p>Our analyses demonstrate that lower allele frequencies, lower sample numbers, population stratification and a possible |D'| value of 1 are particularly susceptible to distortion of sample Hardy-Weinberg equilibrium, which has significant implications for calculation of linkage disequilibrium in small sample sizes (eg HapMap) and rarer alleles (eg paucimorphisms, q < 0.05) that may have particular disease relevance and require improved approaches for meaningful evaluation.</p

Taking sides? Aspect has limited influence on soil environment or litter decomposition in pan-European study of roadside verges

In addition to well-known effects on species ecophysiology, phenology, and distributions, climate change is widely predicted to impact essential ecosystem services such as decomposition and nutrient cycling. While temperature and soil moisture are thought to influence litter decomposition, elucidating consistent soil process responses to observed or predicted shifts in climate have proven difficult to evidence. Here we investigated how aspect (i.e., north-south orientation), a natural model for variation in soil temperature, influenced soil physico-chemical conditions and decomposition of two standardised litter types (Green tea and Rooibos teabags) in Pole-facing (PF) and Equator-facing (EF) roadside verges spanning a 3000 km and 27° latitudinal gradient across Europe. Despite average daily temperatures being 1.5 - 3.0 °C warmer on EF than PF slopes, there were only minor region-specific differences in initial soil physico-chemical conditions and short-term variation in litter decomposition (i.e., litter mass loss was higher in EF-verges for the first month of deployment only) associated with aspect. We conclude that previously observed differences in soil environments and the decomposition process associated with slope orientation, is largely litter or environment specific, although medium-term soil-decomposition in semi-natural grassland ecosystems may also be insensitive to the magnitude of temperature variation within the range predicted by the IPCC SSP1–2.6 emissions scenario. Nonetheless, consistent average and extreme temperature differences between adjacent PF- and EF-aspects along roadside verges provides a model system to explore exactly how resilient the soil environment and the micro-organisms responsible for decomposition, are to temperature variation

Meanings given to algebraic symbolism in problem posing

Some errors in the learning of algebra suggest students have difficulties giving meaning to algebraic symbolism. In this paper, we use problem posing in order to analyze the students’ capacity to assign meaning to algebraic symbolism and the difficulties that students encounter in this process depending on the characteristics of the algebraic statements given. We designed a written questionnaire composed of eight closed algebraic statements expressed symbolically, which was administered to 55 students who had finished their compulsory education and that had some previous experience in problem posing. In our analysis of the data, we examine both syntactic and semantic structures of the problem posed. We note that in most cases students posed problems with syntactic structures different to those given. They did not include computations within variables, and changed the kinds of relationships connecting variables. Students easily posed problems for statements with additive structures. Other differences in the type of problems posed depend on the characteristics of the given statements

Historical Legacies in World Amphibian Diversity Revealed by the Turnover and Nestedness Components of Beta Diversity

Historic processes are expected to influence present diversity patterns in combination with contemporary environmental factors. We hypothesise that the joint use of beta diversity partitioning methods and a threshold-based approach may help reveal the effect of large-scale historic processes on present biodiversity. We partitioned intra-regional beta diversity into its turnover (differences in composition caused by species replacements) and nestedness-resultant (differences in species composition caused by species losses) components. We used piecewise regressions to show that, for amphibian beta diversity, two different world regions can be distinguished. Below parallel 37, beta diversity is dominated by turnover, while above parallel 37, beta diversity is dominated by nestedness. Notably, these regions are revealed when the piecewise regression method is applied to the relationship between latitude and the difference between the Last Glacial Maximum (LGM) and the present temperature but not when present energy-water factors are analysed. When this threshold effect of historic climatic change is partialled out, current energy-water variables become more relevant to the nestedness-resultant dissimilarity patterns, while mountainous areas are associated with higher spatial turnover. This result suggests that nested patterns are caused by species losses that are determined by physiological constraints, whereas turnover is associated with speciation and/or Pleistocene refugia. Thus, the new threshold-based view may help reveal the role of historic factors in shaping present amphibian beta diversity patterns

Uptake of genetic testing and long-term tumor surveillance in von Hippel-Lindau disease

<p>Abstract</p> <p>Background</p> <p>von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome caused by germline mutations in the <it>VHL </it>gene. Patients have significant morbidity and mortality secondary to vascular tumors. Disease management is centered on tumor surveillance that allows early detection and treatment. Presymptomatic genetic testing is therefore recommended, including in at-risk children.</p> <p>Methods</p> <p>We tested 17 families (n = 109 individuals) for <it>VHL </it>mutations including 43 children under the age of 18. Personalized genetic counseling was provided pre and post-test and the individuals undergoing presymptomatic testing filled out questionnaires gathering socio-demographic, psychological and psychiatric data. Mutation analysis was performed by direct sequencing of the <it>VHL </it>gene. Mutation-carriers were screened for VHL disease-related tumors and were offered follow-up annual examinations.</p> <p>Results</p> <p>Mutations were identified in 36 patients, 17 of whom were asymptomatic. In the initial screening, we identified at least one tumor in five of 17 previously asymptomatic individuals. At the end of five years, only 38.9% of the mutation-carriers continued participating in our tumor surveillance program. During this time, 14 mutation carriers developed a total of 32 new tumors, three of whom died of complications. Gender, education, income, marital status and religiosity were not found to be associated with adherence to the surveillance protocol. Follow-up adherence was also independent of pre-test depression, severity of disease, or number of affected family members. The only statistically significant predictor of adherence was being symptomatic at the time of testing (OR = 5; 95% CI 1.2 - 20.3; p = 0.02). Pre-test anxiety was more commonly observed in patients that discontinued follow-up (64.7% vs. 35.3%; p = 0.01).</p> <p>Conclusions</p> <p>The high initial uptake rate of genetic testing for VHL disease, including in minors, allowed the discontinuation of unnecessary screening procedures in non mutation-carriers. However, mutation-carriers showed poor adherence to long-term tumor surveillance. Therefore, many of them did not obtain the full benefit of early detection and treatment, which is central to the reduction of morbidity and mortality in VHL disease. Studies designed to improve adherence to vigilance protocols will be necessary to improve treatment and quality of life in patients with hereditary cancer syndromes.</p

Oxidative Stress Mediates Physiological Costs of Begging in Magpie (Pica pica) Nestlings

[Background] Theoretical models predict that a cost is necessary to guarantee honesty in begging displays given by offspring to solicit food from their parents. There is evidence for begging costs in the form of a reduced growth rate and immunocompetence. Moreover, begging implies vigorous physical activity and attentiveness, which should increase metabolism and thus the releasing of pro-oxidant substances. Consequently, we predict that soliciting offspring incur a cost in terms of oxidative stress, and growth rate and immune response (processes that generate pro-oxidants substances) are reduced in order to maintain oxidative balance. [Methodology/Principal Findings] We test whether magpie (Pica pica) nestlings incur a cost in terms of oxidative stress when experimentally forced to beg intensively, and whether oxidative balance is maintained by reducing growth rate and immune response. Our results show that begging provokes oxidative stress, and that nestlings begging for longer bouts reduce growth and immune response, thereby maintaining their oxidative status. [Conclusions/Significance] These findings help explaining the physiological link between begging and its associated growth and immunocompetence costs, which seems to be mediated by oxidative stress. Our study is a unique example of the complex relationships between the intensity of a communicative display (begging), oxidative stress, and life-history traits directly linked to viability.GM-R was supported by the Spanish Government (Ministerio de Ciencia y Tecnología, “Juan de la Cierva” program), and TR was supported by the Consejo Superior de Investigaciones Científicas (CSIC; Proyectos Intramurales Especiales)