Report on fetal mummification in the scalloped hammerhead shark Sphyrna lewini

This study describes the fetal mummification process in two embryos of a 310 cm total length scalloped hammerhead shark Sphyrna lewini caught in southeastern Brazil, in December 2017. Fourteen embryos were observed in total, in which two males in the left uterus presented different stages of mummification. Both mummified embryos were covered by an exudate (i.e., a mucous substance), indicating a hematic mummification process. All embryos were at the placentotrophic stage of development, indicating that they were close to parturition. An intrinsic characteristic is suggested as possible etiology for this condition, such as umbilical torsion, because both embryos were at different sizes and, therefore, at different development stages. In addition, the sample size did not allow the authors to presume any pollution effect once only one female was observed. Finally, fetal mummification and other embryonic development disorders might have populational impacts due to reduction in embryo survival and, consequently, recruitment. For this reason and considering that S. lewini is categorized as a “critically endangered species,” this study's results have conservational relevance.     

Contribution of S-Layer Proteins to the Mosquitocidal Activity of Lysinibacillus sphaericus

Lysinibacillus sphaericus strains belonging the antigenic group H5a5b produce spores with larvicidal activity against larvae of Culex mosquitoes. C7, a new isolated strain, which presents similar biochemical characteristics and Bin toxins in their spores as the reference strain 2362, was, however, more active against larvae of Culex mosquitoes. The contribution of the surface layer protein (S-layer) to this behaviour was envisaged since this envelope protein has been implicated in the pathogenicity of several bacilli, and we had previously reported its association to spores. Microscopic observation by immunofluorescence detection with anti S-layer antibody in the spores confirms their attachment. S-layers and BinA and BinB toxins formed high molecular weight multimers in spores as shown by SDS-PAGE and western blot detection. Purified S-layer from both L. sphaericus C7 and 2362 strain cultures was by itself toxic against Culex sp larvae, however, that from C7 strain was also toxic against Aedes aegypti. Synergistic effect between purified S-layer and spore-crystal preparations was observed against Culex sp. and Aedes aegypti larvae. This effect was more evident with the C7 strain. In silico analyses of the S-layer sequence suggest the presence of chitin-binding and hemolytic domains. Both biochemical characteristics were detected for both S-layers strains that must justify their contribution to pathogenicity.     

Chip-calorimetry provides real time insights into the inactivation of biofilms by predatory bacteria

Control or removal of undesired biofilms has frequently been found to be quite difficult. In addition to biocidal or antibiotic chemicals or materials designed to prevent biofouling, biological control agents appear to be promising. Reports of bacterial predators eradicating biofilms or eliminating pathogens motivate a more systematic screening of biofilm-eliminating bacterial predators. Unfortunately, the analysis of the eradication process is demanding. In the present study, chip-calorimetry was applied to monitor the elimination of Pseudomonas sp. biofilms by Bdellovibrio bacteriovorus. The method uses metabolic heat as a real-time parameter for biofilm activity. The method is non-invasive, fast and convenient due to real-time data acquisition. In addition, heat-production data can reveal information about the energetics of the predator–prey interaction. The calorimetric results were validated by confocal laser scanning microscopy. The approach described may be useful for the screening of biofilm susceptibility to different predators.     

Low-Dose Sarin Exposure Produces Long Term Changes in Brain Neurochemistry of Mice

Sarin is a toxic organophosphorus (OP) nerve agent that has been reported to cause long-term alterations in behavioral and neuropsychological processes. The present study was designed to investigate the effect of low dose sarin exposure on the monoamine neurotransmitter systems in various brain regions of mice. The rationale was to expand our knowledge about the noncholinergic neurochemical alterations associated with low dose exposure to this cholinesterase inhibitor. We analyzed the levels of monoamines and their metabolites in different brain areas after exposure of male C57BL/6 mice to a subclinical dose of sarin (0.4 LD50). Mice did not show any signs of cholinergic toxicity or pathological changes in brain tissue. At 1, 4 and 8 weeks post-sarin exposure brains were collected for neurochemical analysis. A significant decrease in the dopamine (DA) turnover, as measured by the metabolite to parent ratio, was observed in the frontal cerebral cortex (FC) at all time points tested. DA turnover was significantly increased in the amygdala at 4 weeks but not at 1 or 8 weeks after exposure. The caudate nucleus displayed a decrease in DA turnover at 1 week but no significant change was observed at 4 and 8 weeks suggesting a reversible effect. In addition to this, serotonin (5-HT) levels were transiently altered at various time points in all the brain regions studied (increase in FC, caudate nucleus and decrease in amygdala). Since there were no signs of cholinergic toxicity or cell death after sarin exposure, different non-cholinergic mechanisms may be involved in regulating these effects. Our results demonstrate that non-symptomatic dose of OP nerve agent sarin has potent long-term, region-specific effects on the monoaminergic neurotransmitter systems. Data also suggests differential effects of sarin on the various DA projections. These neurochemical alterations could be associated with long term behavioral and neuropsychological changes associated with low dose OP exposure.     

Chronic Treatment with Atrial Natriuretic Peptide in Spontaneously Hypertensive Rats: Beneficial Renal Effects and Sex Differences

Objective

The aim of this study was to investigate the effects of chronic treatment with atrial natriuretic peptide (ANP) on renal function, nitric oxide (NO) system, oxidative stress, collagen content and apoptosis in kidneys of spontaneously hypertensive rats (SHR), as well as sex-related differences in the response to the treatment.

Methods

10 week-old male and female SHR were infused with ANP (100 ng/h/rat) or saline (NaCl 0.9%) for 14 days (subcutaneous osmotic pumps). Systolic blood pressure (SBP) was recorded and diuresis and natriuresis were determined. After treatment, renal NO synthase (NOS) activity and eNOS expression were evaluated. Thiobarbituric acid-reactive substances (TBARS), glutathione concentration and glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were determined in the kidney. Collagen was identified in renal slices by Sirius red staining and apoptosis by Tunel assay.

Results

Female SHR showed lower SBP, oxidative stress, collagen content and apoptosis in kidney, and higher renal NOS activity and eNOS protein content, than males. ANP lowered SBP, increased diuresis, natriuresis, renal NOS activity and eNOS expression in both sexes. Renal response to ANP was more marked in females than in males. In kidney, ANP reduced TBARS, renal collagen content and apoptosis, and increased glutathione concentration and activity of GPx and SOD enzymes in both sexes.

Conclusions

Female SHR exhibited less organ damage than males. Chronic ANP treatment would ameliorate hypertension and end-organ damage in the kidney by reducing oxidative stress, increasing NO-system activity, and diminishing collagen content and apoptosis, in both sexes.     

Performance of HIV Prevention of Mother-To-Child Transmission Programs in Sub-Saharan Africa: Longitudinal Assessment of 64 Nevirapine-Based Programs Implemented in 25 Countries, 2000-2011

Background

To evaluate the performance and to identify predictive factors of performance in prevention of mother-to-child HIV transmission programs (PMTCT) in sub-Saharan African countries.

Methods

From 2000 to 2011, PMTCT programs included in the Viramune Donation Programme (VDP) were prospectively followed. Each institution included in the VDP provided data on program implementation, type of management institution, number of PMTCT sites, key programs outputs (HIV counseling and testing, NVP regimens received by mothers and newborns). Nevirapine Coverage Ratio (NCR), defined as the number of women who should have received nevirapine (observed HIV prevalence x number of women in antenatal care), was used to measure performance. Included programs were followed every six months through progress reports.

Results

A total of 64 programs in 25 sub-Saharan African countries were included. The mean program follow-up was 48.0 months (SD = 24.5); 20,084,490 women attended in antenatal clinics were included. The overall mean NCR was 0.52 (SD = 0.25), with an increase from 0.37 to 0.57 between the first and last progress reports (p<.0001); NCR increased by 3.26% per year-program. Between the first and the last report, the number of women counseled and tested increased from 64.3% to 86.0% (p<.0001), the number of women post-counseled from 87.5% to 91.3% (p = 0.08). After mixed linear regression analysis, type of responsible institution, number of women attended in ANC, and program initiation in 2005-2006 were significant predictive factors associated with the NCR. The effect of the time period increased from earlier to later periods.

Conclusion

A longitudinal assessment of large PMTCT programs shows that scaling-up of programs was increased in sub-Saharan African countries. The PMTCT coverage increased throughout the study period, especially after 2006. Performance may be better for programs with a small or medium number of women attended in ANC. Identification of factors that predict PMTCT program performance may help in the development and expansion of additional large PMTCT services in sub-Saharan Africa.     

Cruzipain Activates Latent TGF-β from Host Cells during T. cruzi Invasion

Several studies indicate that the activity of cruzipain, the main lysosomal cysteine peptidase of Trypanosoma cruzi, contributes to parasite infectivity. In addition, the parasitic invasion process of mammalian host cells is described to be dependent on the activation of the host TGF-β signaling pathway by T. cruzi. Here, we tested the hypothesis that cruzipain could be an important activator of latent TGF-β and thereby trigger TGF-β-mediated events crucial for the development of Chagas disease. We found that live epimastigotes of T. cruzi, parasite lysates and purified cruzipain were able to activate latent TGF-β in vitro. This activation could be inhibited by the cysteine peptidase inhibitor Z-Phe-Ala-FMK. Moreover, transfected parasites overexpressing chagasin, a potent endogenous cruzipain inhibitor, prevented latent TGF-β activation. We also observed that T. cruzi invasion, as well as parasite intracellular growth, were inhibited by the administration of Z-Phe-Ala-FMK or anti-TGF-β neutralizing antibody to Vero cell cultures. We further demonstrated that addition of purified cruzipain enhanced the invasive activity of trypomastigotes and that this effect could be completely inhibited by addition of a neutralizing anti-TGF-β antibody. Taken together, these results demonstrate that the activities of cruzipain and TGF-β in the process of cell invasion are functionally linked. Our data suggest that cruzipain inhibition is an interesting chemotherapeutic approach for Chagas disease not only because of its trypanocidal activity, but also due to the inhibitory effect on TGF-β activation.     

Complex Interaction of Deferasirox and Pythium insidiosum: Iron-Dependent Attenuation of Growth In Vitro and Immunotherapy-Like Enhancement of Immune Responses In Vivo

Pythium insidiosum iron acquisition mechanisms are unknown. We previously showed that the iron chelator deferasirox had weak activity in vitro and in rabbits with experimental pythiosis. Here we show that deferasirox causes damage to P. insidiosum hyphae in vitro, but that activity is diminished in the presence of exogenous iron. The tissue activity of the proinflammatory enzyme adenosine deaminase and the histological pattern observed in pythiosis lesions of rabbits treated with deferasirox were similar to the ones in animals treated with immunotherapy.