Advances in the understanding of leishmaniasis progression indicate that cellular interactions more complex than the Th1/Th2 paradigm define the course of infection. Th17 cells are a crucial ...modulator of adaptive immunity against
parasites acting mainly on neutrophil recruitment and playing a dual role at the site of infection. This review describes the roles of both these cell types in linking innate defense responses to the establishment of specific immunity. We focus on the Th17-neutrophil interaction as a crucial component of anti-
immunity, and the clinical evolution of cutaneous or visceral leishmaniasis. To date, information obtained through experimental models and patient evaluations suggests that the influence of the presence of interleukin (IL)-17 (the main cytokine produced by Th17 cells) and neutrophils during
infections is strictly dependent on the tissue (skin or liver/spleen) and parasite species. Also, the time at which neutrophils are recruited, and the persistence of IL-17 in the infection microenvironment, may also be significant. A clearer understanding of these interactions will enable better measurement of the influence of IL-17 and its regulators, and contribute to the identification of disease/resistance biomarkers.
Strongyloides stercoralis infection in immunocompromised subjects, including chronic alcoholics, can lead to a severe disease. Moreover, its prevalence in alcoholic patients seems to be higher than ...that in the general population. The aims of this study were to evaluate the frequency of S. stercoralis infection in alcoholic patients and to investigate the influence of alcohol intake on the parasite load, as well as to evaluate the sensitivity of three different parasitological methods according to the larval output. Fecal samples of 1290 chronic alcoholic patients were examined by spontaneous sedimentation, Baermann–Moraes, and agar plate culture (APC) methods. S. stercoralis was the most frequent parasite found (14.5%; n = 187). Alcoholic individuals infected with Strongyloides stercoralis had a higher daily consumption of alcohol than those who were not infected, 528.6 and 403.0 g/day, respectively (p < 0.05). In addition, individuals with higher alcohol intake presented an increase in parasite load. The S. stercoralis diagnostic method with the highest sensitivity was APC, 97.9% (183/187). In conclusion, S. stercoralis seems to be the most frequent parasite found in alcoholic individuals from endemic areas and alcohol intake is positively associated with S. stercoralis larvae output. In addition, this study confirms that APC is the most sensitive parasitological method used for Strongyloides diagnosis.
While around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production 1. Most of these production forests have ...been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity 2,3. Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al.4 found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin 5 to assess the main drivers of time-to-recovery of post-logging tree carbon (Table S1). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions.
Rutishauser et al. assess the main drivers underlying the time taken for a logged forest to recover its carbon capture and find that forests with reduced impact logging recover more quickly.
Several genome-wide association studies have been conducted to investigate the influence of genetic polymorphisms in the development of allergic diseases, but few of them have included the X ...chromosome. The aim of present study was to perform an X chromosome-wide association study (X-WAS) for asthma symptoms. The study included 1307 children of which 294 were asthma cases. DNA was genotyped using 2.5 HumanOmni Beadchip from Illumina. Statistical analyses were performed in PLINK 1.9, MACH 1.0 and Minimac2. The variant rs12007907 (g.29483892C>A) in IL1RAPL gene was suggestively associated with asthma symptoms in discovery set (odds ratio (OR)=0.49, 95% confidence interval (CI): 0.37-0.67; P=3.33 × 10
). This result was replicated in the ProAr cohort in men only (OR=0.45, 95% CI: 0.21-0.95; P=0.038). Furthermore, investigating the functional role of the rs12007907 on the production a Th2-type cytokine, IL-13, we found a negative association between the minor allele A with IL-13 production in the discovery set (P=0.044). Gene-based analysis revealed that NUDT10 was the most consistently associated with asthma symptoms in discovery sample. In conclusion, the rs12007907 variant in IL1RAPL gene was negatively associated with asthma and IL-13 production in our study and a sex-specific association was observed in one of the validation samples. It suggests an effect on asthma susceptibility and may explain differences in severe asthma frequency between women and men.
In the current study, median lethal concentrations (LC50) were obtained in the brine shrimp assay (BSA) for 31 methanol and water plant extracts representing 21 Amazonian plant species, most of which ...are used in traditional medicine. The following species presented extracts with LC50 values less than 50 µg/ml: Croton cajucara Benth., Micrandropsis scleroxylon W.A. Rodrigues, Piper aduncum L., P. hostmannianum (Miq.) C. DC., P. tuberculatum Jacq., Protium aracouchini (Aubl.) Marchand, and Tapura amazonica Poepp. The methanol extract of T. amazonica Poepp., a species known to be toxic according to ethnobotanic reports, was the most active (LC50 1.2 µg/ml). The data presented are considered useful as general toxicity parameters, and their relevance in the context of discovery of new antitumor agents and potential sources of (new) bioactive compounds in the Amazonian flora is discussed.
The presence and localization of storage polysaccharides and of polysaccharides as cell structure constituents of Paracoccidioides brasiliensis yeast‐like cells and protoplasts were studied using the ...periodic acid‐thiocarbohydrazide‐silver proteinate (PATAg) technique. Yeast‐like cells presented glycogen particles in the form of rosettes, which were mostly concentrated in regions of the cytoplasm. Cells in the budding process presented small amounts of glycogen in their matrix. The intracellular membranes and the attachment of the mother cell to the bud were clearly labelled by silver, demonstrating a large amount of glycoconjugates. The protoplasts presented a small amount of glycogen in their cytoplasm, a reduction probably due to the enzymatic treatment to which the cells were submitted.
Zusammenfassung. Vorkommen und Lokalisation von Speicherpolysacchariden und Struktur‐polysacchariden wurden mittels PATAg‐Technik an der Hefephase und an Protoplasten von Paracoccidioides brasiliensis untersucht. Zellen der Hefephase zeigten Glykogen‐Rosetten meist in zytoplasmatischen Regionen konzentriert. Knospende Hefezellen hatten geringe Glykogen‐Mengen in ihrer Matrix. Die intrazellulären Membranen und der Grenzbereich zwischen Mutterzelle und Knospe waren deutlich silbermarkiert, was auf eine hohe Konzentration von Glykokonjugaten hinweist. Protoplasten zeigten geringe Glykogen‐Konzentrationen im Zytoplasma, wahrscheinlich bedingt durch die Enzymbehandlung zur Protoplastentransformation.
An ultrastructural study was conducted on yeast‐like Paracoccidioides brasiliensis cells grown on liquid and solid peptone—yeast extract—glucose medium. A large proportion of cells grown in liquid ...medium presented cytoplasmic damage compared with the cells grown on solid medium, which remained intact, suggesting that agar plays an important role in the development of this fungus.
The action of the enzymes novozym 234, chitinase and zymolyase 20T on the yeast-like cells of Paracoccidioides brasiliensis was studied in an attempt to obtain protoplast release. Three enzyme ...systems were used: the first consisted of novozym 234 and chitinase plus 0.2 M phosphate buffer, 0.9 M sorbitol and 0.5 M sodium thioglycolate; the second consisted of novozym 234, chitinase, zymolyase 20T, buffer and osmotic stabilizer, with no sodium thioglycolate; the third consisted of the same enzymes as used in the second system but at twice the concentration, plus buffer and osmotic stabilizer. Protoplasts were only released from 72-h-old cells cultured on solid peptone-yeast extract-glucose medium (PYG) treated with the third enzyme system. Sodium thioglycolate used as pretreatment favoured protoplast release but had no such action when added to the enzyme solution, possibly by altering the activity of the enzymes, novozym 234 in particular. The osmotic stabilizer used, 0.9 M sorbitol, was probably one of the factors, in addition to the enzymes, responsible for the cytoplasmic changes observed by transmission electron microscopy in yeast phase cells and in their protoplasts.
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