Atrophic cardiac remodeling induced by taurine deficiency in wistar rats

Introduction

Micronutrient deficiency is observed in heart failure patients. Taurine, for example, represents 50% of total free amino acids in the heart, and in vivo studies have linked taurine deficiency with cardiomyopathy.

Methods

Thirty-four male Wistar rats (body weight = 100 g) were weighed and randomly assigned to one of two groups: Control (C) or taurine-deficient (T (-)). Beta-alanine at a concentration of 3% was added to the animals’ water to induce taurine deficiency in the T (-) group. On day 30, the rats were individually submitted to echocardiography; morphometrical and histopathological evaluation and metalloproteinase activity, oxidative stress and inflammation evaluation were performed. Tissue samples were collected to determine the taurine concentration in the heart.

Results

Taurine deficiency led to decreases in: ventricular wall thickness, left ventricle dry weight, myocyte sectional area, left ventricle posterior wall thickness and ventricular geometry. With regard to heart function, the velocity of the A wave, the ratio between the E and A wave, the ejection fraction, fractional shortening and cardiac output values were decreased in T (-) rats, suggesting abnormal diastolic and systolic function. Increased fibrosis, inflammation and increased activation of metalloproteinases were not observed. Oxidative stress was increased in deficient animals.

Conclusions

These data suggest that taurine deficiency promotes structural and functional cardiac alterations with unique characteristics.     

How do genetic correlations affect species range shifts in a changing environment?

Species may be able to respond to changing environments by a combination of adaptation and migration. We study how adaptation affects range shifts when it involves multiple quantitative traits evolving in response to local selection pressures and gene flow. All traits develop clines shifting in space, some of which may be in a direction opposite to univariate predictions, and the species tracks its environmental optimum with a constant lag. We provide analytical expressions for the local density and average trait values. A species can sustain faster environmental shifts, develop a wider range and greater local adaptation when spatial environmental variation is low (generating low migration load) and multitrait adaptive potential is high. These conditions are favoured when nonlinear (stabilising) selection is weak in the phenotypic direction of the change in optimum, and genetic variation is high in the phenotypic direction of the selection gradient.     

Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda

Abstract

Candida yeast infections are the fourth leading cause of death worldwide. Peptides with antimicrobial activity are a promising alternative treatment for such infections. Here, the antifungal activity of a new antimicrobial peptide—PEP-IA18—was evaluated against Candida species. PEP-IA18 was designed from the primary sequence of profilin, a protein from Spodoptera frugiperda, and displayed potent activity against Candida albicans and Candida tropicalis, showing a minimum inhibitory concentration (MIC) of 2.5?µM. Furthermore, the mechanism of action of PEP-IA18 involved interaction with the cell membrane (ergosterol complexation). Treatment at MIC and/or 10?×?MIC significantly reduced biofilm formation and viability. PEP-IA18 showed low toxicity toward human fibroblasts and only revealed hemolytic activity at high concentrations. Thus, PEP-IA18 exhibited antifungal and anti-biofilm properties with potential applicability in the treatment of infections caused by Candida species.     

Micropropagation of the pistachio and its rootstocks by temporary immersion system

Although several studies have been reported on the micropropagation of the pistachio and its rootstocks, to date none of them had been efficient on the mass production of these plants in bioreactor systems. Thus, the micropropagation of juvenile pistachio shoot tips and nodal buds was investigated in a temporary immersion bioreactor system (RITA^®) and on a conventional semi-solid medium. Among the tested immersion conditions, immersion for 24 min every 16 h reduced vitrification and improved proliferation in the pistachio. Interactions were evident in immersion time and frequency in nodal segments. Nodal buds were better than shoot tips as the highest multiple shoot formation was recorded in MS medium containing 4 mg L^?1 BA and 0.1 mg L^?1 GA₃ in RITA^®. Although shoot tip necrosis (STN) was observed in shoots proliferated on semi-solid MS medium, such a symptom did not occur in shoots sprouted in the RITA^®. Additionally, these optimized conditions were applied to nodal buds of mature male pistachio ‘Atl?’ and Pistacia rootstocks (P. khinjuk Stocks and P. atlantica Desf.), and the micropropagation in the bioreactor system, in comparison to the semi-solid medium, was also improved. Furthermore, in vitro rooting of pistachio plantlets, despite the lower range (27.5 %), was also achieved in RITA^®. However, rooting was better on semi-solid medium for all tested species (ranged between 50 and 70 %). The results of this study showed that RITA^® could be used for the mass propagation of pistachio and its rootstocks, as well as for other woody plant species.     

QTL analysis of frost damage in pea suggests different mechanisms involved in frost tolerance

Key message

Avoidance mechanisms and intrinsic resistance are complementary strategies to improve winter frost tolerance and yield potential in field pea.

Abstract

The development of the winter pea crop represents a major challenge to expand plant protein production in temperate areas. Breeding winter cultivars requires the combination of freezing tolerance as well as high seed productivity and quality. In this context, we investigated the genetic determinism of winter frost tolerance and assessed its genetic relationship with yield and developmental traits. Using a newly identified source of frost resistance, we developed a population of recombinant inbred lines and evaluated it in six environments in Dijon and Clermont-Ferrand between 2005 and 2010. We developed a genetic map comprising 679 markers distributed over seven linkage groups and covering 947.1 cM. One hundred sixty-one quantitative trait loci (QTL) explaining 9–71 % of the phenotypic variation were detected across the six environments for all traits measured. Two clusters of QTL mapped on the linkage groups III and one cluster on LGVI reveal the genetic links between phenology, morphology, yield-related traits and frost tolerance in winter pea. QTL clusters on LGIII highlighted major developmental gene loci (Hr and Le) and the QTL cluster on LGVI explained up to 71 % of the winter frost damage variation. This suggests that a specific architecture and flowering ideotype defines frost tolerance in winter pea. However, two consistent frost tolerance QTL on LGV were independent of phenology and morphology traits, showing that different protective mechanisms are involved in frost tolerance. Finally, these results suggest that frost tolerance can be bred independently to seed productivity and quality.     

Comparative incidence of cancer in HIV-AIDS patients and transplant recipients

BackgroundStudies have found a relationship between decreased immunity and increased incidence of cancer.MethodsA systematic review of observational studies evaluating the incidence of cancer in both organ recipients and people with HIV/AIDS compared with the general population. Eligible studies were searched up to March 2011 in the following databases: Pubmed, Embase, Scielo, Cancerlit and Google scholar. In this study, the standardized incidence ratios (SIR) of cancer in people with HIV/AIDS and of organ transplant recipients were compared with those found among the general population.ResultsTwenty-five studies of transplant and HIV-associated cancer risk, involving 866 776 people with HIV/AIDS or organ recipients and 21 260 new cases of cancer, were included. The risk for the development of new cancer cases was higher among people with HIV/AIDS (SIR = 4, IC95% 3.78–4.24) and who received organs (SIR = 3.28, IC95% 3.06–3.52) when compared with the general population.ConclusionSimilar SIR in both immunocompromised populations suggests that the weakened immune system is responsible for the increased risk of new cases of cancer among these groups. Research investments are needed to develop effective cancer prevention strategies in these populations.     

Evaluation of the membrane lipid selectivity of the pea defensin Psd1

Psd1, a 46 amino acid residues defensin isolated from the pea Pisum sativum seeds, exhibits anti-fungal activity by a poorly understood mechanism of action. In this work, the interaction of Psd1 with biomembrane model systems of different lipid compositions was assessed by fluorescence spectroscopy. Partition studies showed a marked lipid selectivity of this antimicrobial peptide (AMP) toward lipid membranes containing ergosterol (the main sterol in fungal membranes) or specific glycosphingolipid components, with partition coefficients (K(p)) reaching uncommonly high values of 10(6). By the opposite, Psd1 does not partition to cholesterol-enriched lipid bilayers, such as mammalian cell membranes. The Psd1 mutants His36Lys and Gly12Glu present a membrane affinity loss relative to the wild type. Fluorescence quenching data obtained using acrylamide and membrane probes further clarify the mechanism of action of this peptide at the molecular level, pointing out the potential therapeutic use of Psd1 as a natural antimycotic agent.     

Effect of denture adhesive on the micro-organisms in vivo

doi: 10.1111/j.1741‐2358.2010.00381.x Effect of denture adhesive on the micro‐organisms in vivo Background: Denture adhesives increase the retention and stability of dentures in edentulous patients, especially in cases where salivary flow is impaired or in the management of traumatised oral mucosa. Objectives: The effect of a denture adhesive on the oral flora at different time intervals. Method: Thirty denture‐wearing patients were involved in this study. While half of the group received a denture adhesive, the other half did not. At baseline, 1 and 2 months after delivering the dentures, smear samples were obtained from the saliva, palate and the dentures. Candida albicans, Candida krusei, Candida glabrata, Candida spp., Staphylococcus aureus, Moraxella catarrhalis, α‐haemolytic streptococci, β‐haemolytic streptococci, Pneumococcus aureus, S. anginosus, S. intermedius, S. constellatus, S. sanguis, S. gordonii, S. mitis, S. mutans, S. salivarius, and yeasts were investigated. The data were statistically analysed using anova and repeated measures. Results: Most types of the micro‐organisms were not seen and could not be analysed statistically except α‐haemolytic streptococci and C. albicans. No statistically significant difference was found for α‐haemolytic streptococci and C. albicans in saliva, palate and the denture at all time intervals. Conclusions: Prolonged use of the denture adhesive tested up to 2 months did not yield to increase in micro‐organisms of the oral flora.