Asymptomatic Leishmania infection in HIV-positive outpatients on antiretroviral therapy in Pernambuco,Brazil

BackgroundVisceral leishmaniasis (VL) in HIV-positive individuals is a global health problem. HIV-Leishmania coinfection worsens prognosis and mortality risk, and HIV-Leishmania coinfected individuals are more susceptible to VL relapses. Early initiation of antiretroviral therapy can protect against Leishmania infection in individuals living in VL-endemic areas, and regular use of antiretrovirals might prevent VL relapses in these individuals. We conducted a cross-sectional study in Petrolina, Brazil, an VL-endemic area, to estimate the prevalence of asymptomatic Leishmania cases among HIV-positive outpatients.MethodsWe invited any HIV-positive patients, aged ≥ 18-years-old, under antiretroviral therapy, and who were asymptomatic for VL. Patients were tested for Leishmania with enzyme-linked immunosorbent assays (ELISA)-rK39, immunochromatographic test (ICT)-rK39, direct agglutination test (DAT), latex agglutination test (KAtex), and conventional polymerase chain reaction (PCR). HIV-Leishmania coinfection was diagnosed when at least one VL test was positive.ResultsA total of 483 patients were included. The sample was predominantly composed of single, < 48-years-old, black/pardo, heterosexual males, with fewer than 8 years of schooling. The prevalence of asymptomatic HIV-Leishmania coinfection was 9.11% (44/483). HIV mono-infected and HIV-Leishmania coinfected groups differed statistically significantly in terms of race (p = 0.045), marital status (p = 0.030), and HIV viral load (p = 0.046). Black/pardo patients, married patients, and those with an HIV viral load up to 100,000 copies/ml presented higher odds for HIV-Leishmania coinfection.ConclusionsA considerable number of asymptomatic Leishmania cases were observed among HIV-positive individuals in a VL-endemic area. Given the potential impact on transmission and health costs, as well as the impact on these coinfected individuals, studies of asymptomatic Leishmania carriers can be useful for guiding public health policies in VL-endemic areas aiming to control and eliminate the disease.     

Species Distribution Modelling predicts habitat suitability and reduction of suitable habitat under future climatic scenario for Sclerophrys perreti: A critically endangered Nigerian endemic toad

Sclerophrys perreti is a critically endangered Nigerian native frog currently imperilled by human activities. A better understanding of its potential distribution and habitat suitability will aid in conservation; however, such knowledge is limited for S. perreti. Herein, we used a species distribution model (SDM) approach with all known occurrence data (n = 22) from our field surveys and primary literature, and environmental variable predictors (19 bioclimatic variables, elevation and land cover) to elucidate habitat suitability and impact of climate change on this species. The SDM showed that temperature and precipitation were the predictors of habitat suitability for S. perreti with precipitation seasonality as the strongest predictor of habitat suitability. The following variable also had a significant effect on habitat suitability: temperature seasonality, temperature annual range, precipitation of driest month, mean temperature of wettest quarter and isothermality. The model predicted current suitable habitat for S. perreti covering an area of 1,115 km². However, this habitat is predicted to experience 60% reduction by 2050 owing to changes in temperature and precipitation. SDM also showed that suitable habitat exists in south-eastern range of the inselberg with predicted low impact of climate change compared to other ranges. Therefore, this study recommends improved conservation measures through collaborations and stakeholder's meeting with local farmers for the management and protection of S. perreti.     

Looking for the Iberian lynx in central Spain: a needle in a haystack?

The Iberian lynx Lynx pardinus has suffered a dramatic reduction in its range throughout the Iberian Peninsula and at present is one of the most endangered mammals in the world. The latest studies report that, out of the 48 breeding areas that existed in 1990, only two populations are left in southern Spain. As a consequence, some of the formerly largest populations, such as Montes de Toledo (central Spain), are to all intents and purposes regarded as extinct. To determine the current distribution of Iberian lynx outside the two recognized populations, we surveyed five different areas where the species is considered extinct and collected 581 faeces for the genetic identification of the species. We identified 18 samples as belonging to Iberian lynx in four out of the five areas studied, providing clear evidence for the presence of lynx in central Spain. In some areas the species was detected repeatedly at different localities and on different dates, indicating a regular occurrence of an unknown number of individuals. The conservation implications of these results are discussed in terms of the genetic importance of the individuals found and future reintroductions of the species from an ongoing captive-breeding programme.     

Oral administration of sodium butyrate attenuates inflammation and mucosal lesion in experimental acute ulcerative colitis

Butyrate is a four-carbon short-chain fatty acid that improves colonic trophism. Although several studies have shown the benefits of butyrate enemas in ulcerative colitis (UC), studies using the oral route are rare in the literature. In the present study, we evaluated the effect of butyrate intake in the immune response associated to UC. For that, mice were fed control or butyrate (0.5% sodium butyrate) diets for 14 days. Acute UC was induced by dextran sulphate sodium (DSS, 2.5%), replacing drinking water. The results showed that, in UC animals, oral butyrate significantly improved trophism and reduced leukocyte (eosinophil and neutrophil) infiltration in the colon mucosa and improved the inflammatory profile (activated macrophage, B and T lymphocytes) in cecal lymph nodes. In the small intestine, although mucosa histology was similar among groups, DSS treatment reduced duodenal transforming growth factor-β, increased interleukin-10 concentrations and increased memory T lymphocytes and dendritic cells in Peyer's patches. Butyrate supplementation was able to revert these alterations. When cecal butyrate concentration was analyzed in cecal content, it was still higher in the healthy animals receiving butyrate than in the UC+butyrate and control groups. In conclusion, our results show that oral administration of sodium butyrate improves mucosa lesion and attenuates the inflammatory profile of intestinal mucosa, local draining lymph nodes and Peyer's patches of DSS-induced UC. Our results also highlight the potential use of butyrate supplements as adjuvant in UC treatment.     

Assessing Risk Factors for Migraine: Differences in Gender Transmission

Aim

Our aim was to assess which specific factors are contributing to an increased risk of migraine in a group of 131 Portuguese families.

Methods

We studied 319 first-degree relatives, using a multilevel approach to account for the dependency among members from the same family. We included in the model relative’s gender, the proband’s gender and age-at-onset, to evaluate if any of these variables were associated with relative’s affection status. We also included in the model proband’s migraine subtype. We further assessed female and male transmissions within the proband nuclear family.

Results

Relatives’ gender was found to be a risk factor for migraine (Odds Ratio = 2.86; 95% CI = 1.75–4.67), with females at a higher risk. When splitting probands according to their migraine subtype, we found that none of the variables studied contributed to relatives of MA-probands affection-status. Our results also show a significant difference between proband’s transmission and the gender of the parents and offspring.

Conclusions

With this study, we showed that gender is truly a risk factor for migraine and that a gender-biased transmission is also observed. This reinforce the importance of identifying genes associated with migraine that are modulated by genes located in the sex chromosomes and the study of mitochondrial DNA or X-chromosome and hormonal-related effects associated with migraine susceptibility.     

Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens

Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant neotropical herbivores cultivate symbiotic fungus gardens on large quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers. Using metagenomic and metaproteomic techniques, we characterize the bacterial diversity and physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter and Escherichia. We show that these bacterial communities possess genes associated with lignocellulose degradation and diverse biosynthetic pathways, suggesting that they play a role in nutrient cycling by converting the nitrogen-poor forage of the ants into B-vitamins, amino acids and other cellular components. Our metaproteomic analysis confirms that bacterial glycosyl hydrolases and proteins with putative biosynthetic functions are produced in both field-collected and laboratory-reared colonies. These results are consistent with the hypothesis that fungus gardens are specialized fungus–bacteria communities that convert plant material into energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities in the ecology and evolution of herbivorous metazoans.     

Lack of association between the Val158Met catechol-O-methyltransferase gene polymorphism and methamphetamine dependence

OBJECTIVES: About 25,000 serious methamphetamine abusers live in the Czech Republic among the total population of 10 million. Dependence on methamphetamine is markedly related to the brain neurotransmitter dopamine, metabolised by catechol-O-methyltransferase enzyme. The main aim of the study was to ascertain whether the Val158Met catechol-O-methyltransferase gene polymorphism is associated with methamphetamine dependence in this Central European country. Methods: One hundred and twenty-three subjects dependent on methamphetamine (women N=44), parents of sixty-seven dependent individuals, and four hundred healthy controls (women N=250) were involved into the study. We performed a population-based as well as family-based genetic association studies. Results: We did not find any significant association between the Val158Met catechol-O-methyltransferase gene polymorphism and methamphetamine dependence using the population-based or family-based design (p=0.41-0.66; Chi-Square Test or UNPHASED program, Version 3.1.4, respectively). We found a trend toward a statistically significant difference between the Val allele carriers and Met/Met homozygotes in the frequence of psychotic symptoms induced by methamphetamine (more frequent in Val carriers; p=0.062; Chi-Square Test). Conclusion: Further research involving haplotype analysis and other dopamine-related genetic polymorphisms in large populations is needed. More attention should also be paid to possible role of the Val158Met catechol-O-methyl-transferase gene polymorphism in individual clinical subtypes of dependence on methamphetamine involving e.g. psychotic features or violence.     

Oviposition by a moth suppresses constitutive and herbivore-induced plant volatiles in maize

Plant volatiles function as important signals for herbivores, parasitoids, predators, and neighboring plants. Herbivore attack can dramatically increase plant volatile emissions in many species. However, plants do not only react to herbivore-inflicted damage, but also already start adjusting their metabolism upon egg deposition by insects. Several studies have found evidence that egg deposition itself can induce the release of volatiles, but little is known about the effects of oviposition on the volatiles released in response to subsequent herbivory. To study this we measured the effect of oviposition by Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) moths on constitutive and herbivore-induced volatiles in maize (Zea mays L.). Results demonstrate that egg deposition reduces the constitutive emission of volatiles and suppresses the typical burst of inducible volatiles following mechanical damage and application of caterpillar regurgitant, a treatment that mimics herbivory. We discuss the possible mechanisms responsible for reducing the plant’s signaling capacity triggered by S. frugiperda oviposition and how suppression of volatile organic compounds can influence the interaction between the plant, the herbivore, and other organisms in its environment. Future studies should consider oviposition as a potential modulator of plant responses to insect herbivores.     

Effect of spiders (Arachnida: Araneae) as predators of insect pest in alfalfa crops (Medicago sativa) (Fabaceae) in Argentina

Spiders are predators that reduce insect pest populations in agroecosystems. Trials were conducted to measure the selectivity against different insect preys, the daily consumption, effect of predators alone and together with a known number of preys, and the indirect effect of predators on vegetation. For this, experimental units (1 x 1m) were used covered with a fine plastic mesh. Misumenops pallidus, Oxyopes salticus and Araneus sp. were used as generalist predators, and aphids, weevils, locusts, chrysomelids and Lepidoptera larvae as their potential preys. Among the preys offered, the spiders preferred Lepidoptera larvae compared to the other two pests groups (weevils and aphids). The maximum consumption rate was of 93.33% for Lepidoptera larvae, 25.33% for aphids and 11.67% for weevils. The Q Index values for the three species of spiders showed a positive selectivity only for defoliating larvae. O. salticus showed the highest values of consumption rates while Rachiplusia nu was the most consumed. The maximum value of consumption in 24 hours was showed by O. salticus on R. nu (C) = 2.8. The association of several species of predatory spiders increased the total number of insects captured, and also showed that the addition of spiders caused a decrease in the number of leaves damaged by the effect of lepidopterous larvae.