Mechanisms Involved in the Nociception Triggered by the Venom of the Armed Spider Phoneutria nigriventer

Background

The frequency of accidental spider bites in Brazil is growing, and poisoning due to bites from the spider genus Phoneutria nigriventer is the second most frequent source of such accidents. Intense local pain is the major symptom reported after bites of P. nigriventer, although the mechanisms involved are still poorly understood. Therefore, the aim of this study was to identify the mechanisms involved in nociception triggered by the venom of Phoneutria nigriventer (PNV).

Methodology/Principal Findings

Twenty microliters of PNV or PBS was injected into the mouse paw (intraplantar, i.pl.). The time spent licking the injected paw was considered indicative of the level of nociception. I.pl. injection of PNV produced spontaneous nociception, which was reduced by arachnid antivenin (ArAv), local anaesthetics, opioids, acetaminophen and dipyrone, but not indomethacin. Boiling or dialysing the venom reduced the nociception induced by the venom. PNV-induced nociception is not dependent on glutamate or histamine receptors or on mast cell degranulation, but it is mediated by the stimulation of sensory fibres that contain serotonin 4 (5-HT₄) and vanilloid receptors (TRPV1). We detected a kallikrein-like kinin-generating enzyme activity in tissue treated with PNV, which also contributes to nociception. Inhibition of enzymatic activity or administration of a receptor antagonist for kinin B₂ was able to inhibit the nociception induced by PNV. PNV nociception was also reduced by the blockade of tetrodotoxin-sensitive Na⁺ channels, acid-sensitive ion channels (ASIC) and TRPV1 receptors.

Conclusion/Significance

Results suggest that both low- and high-molecular-weight toxins of PNV produce spontaneous nociception through direct or indirect action of kinin B₂, TRPV1, 5-HT₄ or ASIC receptors and voltage-dependent sodium channels present in sensory neurons but not in mast cells. Understanding the mechanisms involved in nociception caused by PNV are of interest not only for better treating poisoning by P. nigriventer but also appreciating the diversity of targets triggered by PNV toxins.     

Asymmetric reduction of (4S)-(+)-carvone catalyzed by baker's yeast: A green method for monitoring the conversion based on liquid–liquid–liquid microextraction with polypropylene hollow fiber membranes

The α,β-unsaturated carbonyl compound (4S)-(+)-carvone was selectively reduced to (1R,2R,4S)-iso-dihydrocarveol using baker's yeasts. The conversion of the bioreduction reaction was monitored using a green hollow-fiber liquid–liquid–liquid microextraction (HF-LLLME) technique. Several parameters which may affect the bioreduction of (4S)-(+)-carvone, such as temperature, time, substrate/enzyme ratio, pH and buffer concentration, were evaluated. The effect of some additives, such as trehalose, DMSO and the ionic liquid [BMIm][PF₆], was also studied. The (1R,2R,4S)-iso-dihydrocarveol was recovered with 52.7% conversion and diastereoisomeric excess >99% after 48 h of reaction at 40 °C in an aqueous monophasic system, with 0.1 mol L^?1 buffer concentration (pH 7.5) and a substrate/yeast cell mass ratio of 8.0 mg g^?1. The HF-LLLME microextraction technique allowed the optimization of the reaction with a reduction of over 99.5% in relation to the use of organic solvents.     

Souring control in fluid samples of oil industry using a multiple ligand simultaneous docking (MLSD) strategy

We have used docking techniques in order to propose potential inhibitors to the enzymes adenosine phosphosulfate reductase and adenosine triphosphate sulfurylase that are responsible, among other deleterious effects, for causing souring of oil and gas reservoirs. Three candidates selected through molecular docking revealed new and improved polar and hydrophobic interactions with the above-mentioned enzymes. Microbiological laboratory assays performed subsequently corroborated the results of computer modelling that the three compounds can efficiently control the biogenic sulfide production.     

Recovery of the pubic symphysis on primiparous young and multiparous senescent mice at postpartum

It has been observed that parturition has a significant effect on female skeletal architecture and that age alters musculoskeletal tissues and their functions. We therefore hypothesized that multiparity affects the recovery of the pubic symphysis in senescent mice at postpartum and the morphology of the interpubic tissues. The pubic symphysis of primiparous young, virgin senescent (VS) and multiparous senescent (MS) Swiss mice was examined by light microscopy, transmission electron microscopy, morphometric analysis and immunohistochemistry. The mouse pubic symphysis was remodeled during the first pregnancy: the cellular phenotype and morphology changed to ensure a structurally safe birth canal, followed by recovery of the interpubic articulation after birth. The morphology of the pubic symphysis in the VS group was maintained in a state similar to that observed in virgin young mice. In contrast, MS mice exhibited an interpubic ligament characterized by extended fibrocyte-like cells, an opened interpubic articulation gap, compacted and thin collagen fibrils and scarce galectin-3-positive cells. Thus, we found that the cellular and extracellular characteristics of the pubic symphysis were altered by multiparity in senescent mice. These particular tissue characteristics of the MS group might be associated with an impaired recovery process at postpartum. Thus, a better understanding of the alterations that occur in the birth canal, including the pubic symphysis, due to multiparity in reproductively aged mice may contribute to our comprehension of the biological mechanisms that modify the skeleton and pelvic ligaments and even play a role in the murine model of pelvic organ prolapse.     

The galactose‐binding lectin isolated from Bauhinia bauhinioides Mart seeds inhibits neutrophil rolling and adhesion via primary cytokines

In this study, the amino acid sequence and anti‐inflammatory effect of Bauhinia bauhinioides (BBL) lectin were evaluated. Tandem mass spectrometry revealed that BBL possesses 86 amino acid residues. BBL (1 mg/kg) intravenously injected in rats 30 min prior to inflammatory stimuli inhibited the cellular edema induced by carrageenan in only the second phase (21% – 3 h, 19% – 4 h) and did not alter the osmotic edema induced by dextran. BBL also inhibited carrageenan peritoneal neutrophil migration (51%), leukocyte rolling (58%) and adhesion (68%) and the neutrophil migration induced by TNF‐α (64%). These effects were reversed by the association of BBL with galactose, demonstrating that the carbohydrate‐binding domain is essential for lectin activity. In addition, BBL reduced myeloperoxidase activity (84%) and TNF‐α (68%) and IL1‐β (47%) levels. In conclusion, the present investigation demonstrated that BBL contains highly homologous isolectins, resulting in a total of 86 amino acid residues, and exhibits anti‐inflammatory activity by inhibiting neutrophil migration by reducing TNF‐α and IL1‐β levels via the lectin domain. Copyright © 2015 John Wiley & Sons, Ltd.     

Trichoderma aureoviride URM 5158 and Trichoderma hamatum URM 6656 are Biocontrol Agents that act against Cassava Root rot through different Mechanisms

Trichoderma has been used to manage a large number of pathogens, but there is a gap in the mechanisms used by these biocontrol agents regarding the physiological response of cassava plants (Manihot esculenta) when it is subjected to cassava root rot. The aims of this study were to investigate the antagonist activity of ten Trichoderma isolates against Fusarium solani on potato dextrose Agar (PDA), to quantify the chitinase production, to select and test in vivo the best isolate from each experiment and to assess the physiological response of cassava to the production of oxidative enzyme complex production (ascorbate peroxidase, catalase, peroxidase and polyphenol oxidase). All Trichoderma isolates have shown competitive capability against F. solani, and Trichoderma hamatum URM 6656 showed the highest inhibition of pathogen growth (88.91%). All isolates have shown chitinase activity, but Trichoderma aureoviride URM 5158 produced the highest amount of chitinase. T. hamatum URM 6656 and T. aureoviride URM 5158 were selected to be applied in vivo. The two Trichoderma strains reduced 64 and 60% of the disease severity in the shoot and 82 and 84% in the root. Cassava plants infected with Trichoderma have shown the highest peroxidase and ascorbate peroxidase production. Our results have indicated that T. aureoviride URM 5158 is an effective biocontrol agent against cassava root rot caused by F. solani, because it presented competitive antagonist capability in vitro, the highest chitinase production, and reduced the cassava root rot severity. The application of T. aureoviride has led to the maximum enzyme activity of reactive oxygen species group in cassava plants.     

Long-term wheel-running and acute 6-h advances alter glucose tolerance and insulin levels in TALLYHO/JngJ mice

Studies have shown a relationship between circadian rhythm disruptions and type-2 diabetes. This investigation examined the effects of circadian disruption (6-h phase advances) on the progression of diabetes in a type-2 diabetic mouse model –TALLYHO/JngJ – and whether wheel-running can alleviate the effects of the phase advances. 6-h advances alter fasting glucose, glucose tolerance and insulin production. Wheel-running reduced body mass, improved glucose tolerance and reduced insulin in TALLYHO/JngJ and alleviated some of the changes in diabetic symptoms due to 6-h advances. These results indicate that individuals with type-2 diabetes can benefit from physical activity and exercise can be a countermeasure to offset the effects of an acute phase advance.     

New Culicoides Latreille of the subgenus Mataemyia Vargas from Pará, Brazil (Diptera: Ceratopogonidae)

Two new species of Culicoides Latreille of the Neotropical subgenus Mataemyia Vargas are described and illustrated based on female specimens from Juruti, Pará, Brazil and compared with their similar congeners. This paper also presents a diagnosis of the subgenus Mataemyia and a systematic key for the identification of the 19 species of the subgenus.     

Risk Factors for Adverse Prognosis and Death in American Visceral Leishmaniasis: A Meta-analysis

Background

In the current context of high fatality rates associated with American visceral leishmaniasis (VL), the appropriate use of prognostic factors to identify patients at higher risk of unfavorable outcomes represents a potential tool for clinical practice. This systematic review brings together information reported in studies conducted in Latin America, on the potential predictors of adverse prognosis (continued evolution of the initial clinical conditions of the patient despite the implementation of treatment, independent of the occurrence of death) and death from VL. The limitations of the existing knowledge, the advances achieved and the approaches to be used in future research are presented.

Methods/Principal Findings

The full texts of 14 studies conforming to the inclusion criteria were analyzed and their methodological quality examined by means of a tool developed in the light of current research tools. Information regarding prognostic variables was synthesized using meta-analysis. Variables were grouped according to the strength of evidence considering summary measures, patterns and heterogeneity of effect-sizes, and the results of multivariate analyses. The strongest predictors identified in this review were jaundice, thrombocytopenia, hemorrhage, HIV coinfection, diarrhea, age <5 and age >40–50 years, severe neutropenia, dyspnoea and bacterial infections. Edema and low hemoglobin concentration were also associated with unfavorable outcomes. The main limitation identified was the absence of validation procedures for the few prognostic models developed so far.

Conclusions/Significance

Integration of the results from different investigations conducted over the last 10 years enabled the identification of consistent prognostic variables that could be useful in recognizing and handling VL patients at higher risk of unfavorable outcomes. The development of externally validated prognostic models must be prioritized in future investigations.     

Water deficit modulates growth,morphology, and the essential oil profile in Lippia alba L. (Verbenaceae) grown in vitro

Lippia alba (Miller) N.E. Brown is an aromatic plant species of great economic importance due to the medicinal properties of its essential oils, which provide stress relief, respiratory and gastrointestinal disease control, and anti-inflammatory and natural sedative effects. The plant is also effective in biological control against various pathogens and in food preservation. Water deficit is the most critical abiotic factor limiting plant growth and morpho-physiological development, as well as production of secondary metabolism compounds. The objective of this work was to evaluate the effect of water deficit on growth, photosynthesis, essential oil profile, and the expression of genes related to the biosynthesis of these compounds in L. alba grown in vitro. Nodal segments were cultured on medium supplemented with 0, 1, 2, and 3% (w/v) polyethylene glycol for 45 days. Water stress had a negative effect on primary metabolism indicators, such as growth, leaf area, and photosynthetic rate; but a positive effect on amino acid and total protein content. Similarly, secondary metabolism exhibited an increase in linalool but a reduction in germacrene levels under water deficit. These findings provide a deeper understanding of how water deficit affects primary and secondary metabolism in L. alba, showing the potential of this medicinal species to adapt to soils with low water availability, while still being able to grow and synthesize essential oils.