Exotic snakes in São Paulo City, southeastern Brazil: why xenophobia?

Introduced exotic species cause environmental changes and threat public health in target sites. Illegal trade has enhanced this problem. To first report these risks in Brazil, exotic snakes found in São Paulo City (SPC) (23°32 S, 46°38 W), southeastern Brazil, and sent to Instituto Butantan between 1995 and 2000, were listed and characterized by their biological attributes. Seventy-six individuals of sixteen alien species were collected. Euriecians snakes, mainly booids, were predominant. Using multivariate techniques, their ecological niches were compared to those of 26 native species, as a way to point out the resource's availability. To evaluate the potential of successful implantation, two species absent in SPC and considered as problem snakes are included in these analyses: the brown treesnake Boiga irregularis and the habu Trimeresurus flavoviridis. There were niche similarities between these pest snakes, exotic booids and native viperids largely due to the similarities in the chosen prey (mammals), diel activity (nocturnal), color pattern (variegated) and body size (medium to large). To avoid predictable undesirable effects of implanted pest snakes, traffic control and punishment should be improved, as well as parallel environmental education programs.     

Crosstalk between dihydroceramides produced by Porphyromonas gingivalis and host lysosomal cathepsin B in the promotion of osteoclastogenesis

Emerging studies indicate that intracellular eukaryotic ceramide species directly activate cathepsin B (CatB), a lysosomal‐cysteine‐protease, in the cytoplasm of osteoclast precursors (OCPs) leading to elevated RANKL‐mediated osteoclastogenesis and inflammatory osteolysis. However, the possible impact of CatB on osteoclastogenesis elevated by non‐eukaryotic ceramides is largely unknown. It was reported that a novel class of phosphoglycerol dihydroceramide (PGDHC), produced by the key periodontal pathogen Porphyromonas gingivalis upregulated RANKL‐mediated osteoclastogenesis in vitro and in vivo. Therefore, the aim of this study was to evaluate a crosstalk between host CatB and non‐eukaryotic PGDHC on the promotion of osteoclastogenesis. According to a pulldown assay, high affinity between PGDHC and CatB was observed in RANKL‐stimulated RAW264.7 cells in vitro. It was also demonstrated that PGDHC promotes enzymatic activity of recombinant CatB protein ex vivo and in RANKL‐stimulated osteoclast precursors in vitro. Furthermore, no or little effect of PGDHC on the RANKL‐primed osteoclastogenesis was observed in male and female CatB‐knock out mice compared with their wild type counterparts. Altogether, these findings demonstrate that bacterial dihydroceramides produced by P. gingivalis elevate RANKL‐primed osteoclastogenesis via direct activation of intracellular CatB in OCPs.     

P-glycoprotein induction: an antidotal pathway for paraquat-induced lung toxicity

The widespread use of the nonselective contact herbicide paraquat (PQ) has been the cause of thousands of deaths from both accidental and voluntary ingestion. The main target organ for PQ toxicity is the lung. No antidote or effective treatment to decrease PQ accumulation in the lung or to disrupt its toxicity has yet been developed. The present study describes a procedure that leads to a remarkable decrease in PQ accumulation in the lung, together with an increase in its fecal excretion and a subsequent decrease in several biochemical and histopathological biomarkers of toxicity. The administration of dexamethasone (100 mg/kg ip) to Wistar rats, 2 h after PQ intoxication (25 mg/kg ip), decreased the lung PQ accumulation to about 40% of the group exposed to only PQ and led to an improvement in tissue healing in just 24 h as a result of the induction of de novo synthesis of P-glycoprotein (P-gp). The involvement of P-gp in these effects was confirmed by Western blot analysis and by the use of a competitive inhibitor of this transporter, verapamil (10 mg/kg ip), which, given 1 h before dexamethasone, blocked its protective effects, causing instead an increase in lung PQ concentration and an aggravation of toxicity. In conclusion, the induction of P-gp, leading to a decrease in lung levels of PQ and the consequent prevention of toxicity, seems to be a new and promising treatment for PQ poisonings that should be further clinically tested.     

Actin exposure upon tissue injury is a targetable wound site-specific protein marker

BackgroundIdentification of wound-specific markers would represent an important step toward damaged tissue detection and targeted delivery of biologically important materials to injured sites. Such delivery could minimize the amount of therapeutic materials that must be administered and limit potential collateral damage on nearby normal tissues. Yet, biological markers that are specific for injured tissue sites remain elusive.MethodsIn this study, we have developed an immunohistological approach for identification of protein epitopes specifically exposed in wounded tissue sites.ResultsUsing ex-vivo tissue samples in combination with fluorescently-labeled antibodies we show that actin, an intracellular cytoskeletal protein, is specifically exposed upon injury. The targetability of actin in injured sites has been demonstrated in vivo through the specific delivery of anti-actin conjugated particles to the wounded tissue in a lethal rat model of grade IV liver injury.ConclusionsThese results illustrate that identification of injury-specific protein markers and their targetability for specific delivery is feasible.General significanceIdentification of wound-specific targets has important medical applications as it could enable specific delivery of various products, such as expression vectors, therapeutic drugs, hemostatic materials, tissue healing, or scar prevention agents, to internal sites of penetrating or surgical wounds regardless of origin, geometry or location.     

Development of a bioadhesive nanoformulation with Glycyrrhiza glabra L. extract against Candida albicans

Abstract

Glycyrrhiza glabra L. is considered an important source of bioactive compounds. This study aimed at the development of an efficient solution for the treatment of oral candidiasis. Several extracts of Glycyrrhiza glabra L. were prepared using different solvents and their potential in vitro antifungal activity was assessed. Ethanolic extracts showed the most promising results against C. albicans. This extract was incorporated into mucoadhesive nanoparticles (PLA, PLGA and alginate), which were further included in an oral gel, an oral film and a toothpaste, respectively. The results showed that nanoparticles were successfully produced, presenting a mean size among 100–900?nm with high encapsulation efficiency. In vitro studies showed that the most bioadhesive formulation was the oral film with extract-loaded PLGA nanoparticles, followed by the toothpaste with extract-loaded alginate nanoparticles and the oral gel with extract-loaded PLA nanoparticles.     

Host-ectoparasite specificity in a small mammal community in an area of Atlantic Rain Forest (Ilha Grande, State of Rio de Janeiro), Southeastern Brazil

The analyses of the ectoparasite species associated with a small mammal community on Ilha Grande, a coastal island in southern of the state of Rio de Janeiro, Brazil, evaluated the level of host-ectoparasite specificity. Was used the Jaccard index for qualitative data to analyse the similarity. The lowest value of similarity occurred between Proechimys iheringi and Marmosops incanus and between Sciurus aestuans and Nectomys squamipes (Cj=0.08) and the highest between P. iheringi and Oxymycterus sp. (Cj=0.33). This index showed a low value of similarity across the ectoparasite community. The only exception from this pattern of high host specificity occurred with P. iheringi and Oxymycterus sp., which shared five species of ectoparasites. The similarity values, for most of the cases, is smaller than 0.2.     

Different responses of young and expanded lettuce leaves to fungicide Mancozeb: chlorophyll fluorescence,lipid peroxidation,pigments and proline content

This work aimed to study the effects of commercial doses of the fungicide, Mancozeb, on the photosynthetic apparatus of lettuce young leaves (YL) and expanded leaves (EL). Seven days after Mancozeb application, chlorophyll a fluorescence, pigment contents, lipid peroxidation, and proline content were evaluated. Independently of leaf age, Mancozeb treatment reduced the efficiency of photosystem II photochemistry, increased the nonphotochemical quenching and proline content, decreased pigment contents, and induced lipid peroxidation. Moreover, EL showed a more stable photosynthetic apparatus, less prone to oxidative damages compared with YL. The parameters measured proved to be good markers for the rapid and preliminary diagnosis of fungicide toxicity.     

Discriminating the effects of phylogenetic hypothesis,tree resolution and clade age estimates on phylogenetic signal measurements

Understanding how species traits evolved over time is the central question to comprehend assembly rules that govern the phylogenetic structure of communities. The measurement of phylogenetic signal (PS) in ecologically relevant traits is a first step to understand phylogenetically structured community patterns. The different methods available to estimate PS make it difficult to choose which is most appropriate. Furthermore, alternative phylogenetic tree hypotheses, node resolution and clade age estimates might influence PS measurements. In this study, we evaluated to what extent these parameters affect different methods of PS analysis, and discuss advantages and disadvantages when selecting which method to use. We measured fruit/seed traits and flowering/fruiting phenology of endozoochoric species occurring in Southern Brazilian Araucaria forests and evaluated their PS using Mantel regressions, phylogenetic eigenvector regressions (PVR) and K statistic. Mantel regressions always gave less significant results compared to PVR and K statistic in all combinations of phylogenetic trees constructed. Moreover, a better phylogenetic resolution affected PS, independently of the method used to estimate it. Morphological seed traits tended to show higher PS than diaspores traits, while PS in flowering/fruiting phenology depended mostly on the method used to estimate it. This study demonstrates that different PS estimates are obtained depending on the chosen method and the phylogenetic tree resolution. This finding has implications for inferences on phylogenetic niche conservatism or ecological processes determining phylogenetic community structure.