Genes encoding Shiga toxin and the intimin receptor detected in faecal samples collected from wild canids

Background: Enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) are diarrheagenic E. coli that can cause disease in humans. The pathotype EPEC leads to the attaching and effacing lesion, causing damage to the microvilli following to diarrhea. STEC pathotypes produces cytotoxins, which in humans are responsible for hemorrhagic colitis or hemolytic uremic syndrome. Animals are the reservoirs of these pathotypes, especially ruminants. However, other animal’s species can be associated as carriers of EPEC and STEC strains. The aim of this study was to analyze wild canid crab-eating fox (Cerdocyon thous) as potential natural carriers of STEC and EPEC E. coli. Materials, Methods & Results: Seven fecal samples were analyzed from the crab-eating fox of free-living, captured in a peri-urban area. Samples were collected from the rectal ampulla, and the animals were clinic evaluated, being considered healthy at the captured moment. The feces were inoculated on medium MacConkey agar, and then the plates were incubated at 37°C for 24 h. All colony forming units (CFU) were collected by plate washing with ultrapure water (2 mL) and posterior freezing at -20°C. The total bacterial DNA from the CFU collected was extracted, followed by PCR assay to search for three genes: stx1, stx2 (responsible for the synthesis of the Shiga toxin) and tir, which encodes the translocated intimin receptor, related to the A/E lesion formation. Three samples were detected as positive, being one animal detected as carrier of the stx2 gene (STEC strain), while two animals were identified as carrier of the tir gene (EPEC strains).The stx1 gene was not identified on the samples. Also, in the samples, only the presence of one gene studied at a time was observed. Therefore, we have found out that the crab-eating fox can act as reservoirs of STEC and EPEC strains. Discussion: The carrier’s animals of STEC and EPEC strains do not have receptors for the Shiga toxin, serving as asymptomatic vehicle. The wild canids collected and positives to STEC and EPEC E. coli strains analyzed here, did not shown any clinical signs, wherefore they have the potential of being a source of pathogens to other animals and even humans. The observation of this additional wild species, the crab-eating fox, as carriers of STEC and EPEC reinforces the importance of monitoring wild species and the need for caution because of the potential zoonosis. Nevertheless, there are other species of wild animals that were described as rarely-carriers of these pathogens, like deer, wild ruminants and birds. These E. coli pathotypes, potentially foodborne zoonotic pathogens, are acquired by humans from food and water contaminated, by oral-fecal route, or by direct contact with carries animals and their feces. The human contact with wild animals is getting ordinary; because of that, wild animals, like wild canids, may constitute a considerable risk to animal and humans health, mostly by the transmission of these bacteria strains to the environment. In conclusion, the identification of genes encoding Shiga toxin and the intimin receptor in wild canids feces highlight that STEC and EPEC pathogens could be spread by these wild animals. We reinforce that STEC and EPEC pathogens could be naturally carried by wild animals, such as the crab-eating fox, and therefore, is needed further research for better understanding their potential effect, and also the interaction between the pathogen and the host

Diferenciando espécies crípticas de Drosophila através da eletroforese da enzima fosfatase ácida

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Does color polymorphism affect the predation risk on Phalotris lemniscatus (Duméril, Bibron and Duméril, 1854) (Serpentes, Dipsadidae)?

The snake Phalotris lemniscatus is a polymorphic species regarding color, which varies between light shades with a yellow predominance (pale yellow-brown) to darker shades with a red predominance (red-dark). Pale yellow-brown individuals are more frequent in coastal populations while there is a tendency of increasing the frequency of red-dark morphs in inland areas. Considering the variation in substrate color along the species distribution (light/sandy on the coast to reddish and dark/argillaceous in inland areas), we raise the hypothesis that the predation rate of each morph would be lower in sites were its crypsis potential is higher. If correct, this hypothesis would reinforce the idea that the predation risk is one of the factors influencing the spatial structuring in morph frequency distributions in populations of P. lemniscatus. To test this hypothesis, we performed a field experiment using plasticine P. lemniscatus artificial models that represent two morphs: red-dark and pale yellow-brown. The models were distributed in three localities where the following substrate types predominate: light (Coastal Site), intermediary (Lowland Site) and reddish dark (Highland Site). Our predictions were corroborated only at the coastal site, where the less cryptic morph was the most preyed one. We verified that there is a regional variation in the predation risk on different morphs. Thus, the possibility that the selective pressure by predators is a relevant element in the structuring of the frequencies of different morph populations of this species cannot be completely excluded

Molecular identification of shark meat from local markets in southern Brazil based on DNA barcoding : evidence for mislabeling and trade of endangered species

Elasmobranchs, the group of cartilaginous fishes that include sharks and rays, are especially vulnerable to overfishing due to low fecundity and late sexual maturation. A significant number of elasmobranch species are currently overexploited or threatened by fisheries activities. Additionally, several recent reports have indicated that there has been a reduction in regional elasmobranch population sizes. Brazil is an important player in elasmobranch fisheries and one of the largest importers of shark meat. However, carcasses entering the shark meat market have usually had their fins and head removed, which poses a challenge to reliable species identification based on the morphology of captured individuals. This is further complicated by the fact that the internal Brazilian market trades several different elasmobranch species under a common popular name: “cação.” The use of such imprecise nomenclature, even among governmental agencies, is problematic for both controlling the negative effects of shark consumption and informing the consumer about the origins of the product. In this study, we used DNA barcoding (mtDNA, COI gene) to identify, at the species level, “cação” samples available in local markets from Southern Brazil. We collected 63 samples traded as “cação,” which we found to correspond to 20 different species. These included two teleost species: Xiphias gladius (n = 1) and Genidens barbus (n = 6), and 18 species from seven elasmobranch orders (Carcharhiniformes, n = 42; Squaliformes, n = 3; Squatiniformes, n = 2; Rhinopristiformes, n = 4; Myliobatiformes, n = 3; Rajiformes, n = 1; and Torpediniformes, n = 1). The most common species in our sample were Prionace glauca (n = 15) and Sphyrna lewini (n = 14), while all other species were represented by four samples or less. Considering IUCN criteria, 47% of the elasmobranch species found are threatened at the global level, while 53% are threatened and 47% are critically endangered in Brazil. These results underline that labeling the meat of any shark species as “cação” is problematic for monitoring catch allocations from the fishing industry and discourages consumer engagement in conservationist practices through informed decision-making

Chromosome instability and oxidative stress markers in patients with ataxia telangiectasia and their parents

Resumo não disponíve

New benzo(a)pyrene-degrading strains of the Burkholderia cepacia complex prospected from activated sludge in a petrochemical wastewater treatment plant

The prospection of bacteria that are resistant to polyaromatic hydrocarbons (PAH) of activated sludge from a Petrochemical Wastewater Treatment Plant (WWTP) allows investigating potential biodegraders of PAH. For this purpose, sludge samples were cultured with benzo(a)pyrene and/or naphthalene as carbon sources. The recovered isolates were characterized by biochemical methods and identified based on the analysis of the sequence of three genes: 16S, recA and gyrB. The isolated strains were shown to be capable of producing surfactants, which are important for compound degradation. The ability to reduce benzo(a)pyrene in vitro was tested by gas chromatography. After 20 days of experiment, the consortium that was enriched with 1 mg/L of benzo(a)pyrene was able to reduce 30% of the compound when compared to a control without bacteria. The four isolated strains that significantly reduced benzo(a)pyrene belong to the Burkholderia cepacia complex and were identified within the consortium as the species B. cenocepacia IIIa, B. vietnamiensis, B. cepacia, and B. multivorans. This finding demonstrates the biotechnological potential of the B. cepacia complex strains for use in wastewater treatment and bioremediation. Previous studies on hydrocarbon-degrading strains focused mainly on contaminated soil or marine areas. In this work, the strains were prospected from activated sludge in a WWTP and showed the potential of indigenous samples to be used in both improving treatment systems and bioremediation of areas contaminated with petrochemical waste

Chromosome Instability and Oxidative Stress Markers in Patients with Ataxia Telangiectasia and Their Parents

Ataxia telangiectasia (AT) is a rare neurodegenerative disorder, inherited in an autosomal recessive manner. Total blood samples were collected from 20 patients with AT, 13 parents of patients, and 17 healthy volunteers. This study aimed at evaluating the frequency of chromosomal breaks in spontaneous cultures, induced by bleomycin and ionizing radiation, and further evaluated the rates of oxidative stress in AT patients and in their parents, compared to a control group. Three cell cultures were performed to each individual: the first culture did not receive induction to chromosomal instability, the second was exposed to bleomycin, and the last culture was exposed to ionizing radiation. To evaluate the rates of oxidative stress, the markers superoxide dismutase (SOD), catalase (CAT), and thiobarbituric acid (TBARS) were utilized. Significant differences were observed between the three kinds of culture treatments (spontaneous, bleomycin, and radiation induced) and the breaks and chromosomal aberrations in the different groups. The oxidative stress showed no significant differences between the markers. This study showed that techniques of chromosomal instability after the induction of ionizing radiation and bleomycin are efficient in the identification of syndrome patients, with the ionizing radiation being the most effective

Where do they live? Predictive geographic distribution of Tadarida brasiliensis brasiliensis (Chiroptera, Molossidae) in South America

Tadarida brasiliensis, the Brazilian free-tailed bat, is an insectivorous molossid with a wide distribution in the Americas. It occurs in different ecosystems and uses varied shelters, from caves and crevices to human constructions, such as roofs and ceilings. Despite its wide distribution, there are several sampling gaps that make it difficult to identify the regions where the species occurs. This is a particular problem for the subspecies T. brasiliensis brasiliensis in South America, a region with few studies in comparison to North America. Considering these problems involved with identifying the distribution of T. b. brasiliensis in South America, we inferred its distribution based on 121 confirmed occurrences for the subspecies. We created a species distribution model (SDM) using the ensemble approach from the combination of BIOCLIM, SVM, GLM and MaxEnt algorithms. The resulting model suggested that the subspecies is unlikely to occur in the Amazon region and has a positive affinity with human population density, topography, a lower vegetation index, and the precipitation in the driest month. Our results show there is a large continuous area suitable for T. b. brasiliensis in central and eastern South America, with interruptions and narrow areas toward Central America. The population in this last area is separated from a smaller site in Chile by Andean deserts, snowy peaks, and high-altitude points. Our results demonstrated that along its distribution suitable habitat for T. b. brasiliensis is not continuous. The discontinuities in populations require further investigation to determine if there are phylogeographic consequences for the species

Editorial: Molecular systematics and phylogeography of tropical and subtropical biodiversity

Non peer reviewe