Herbicides Tolerance in a Pseudomonas Strain Is Associated With Metabolic Plasticity of Antioxidative Enzymes Regardless of Selection.

Agriculture uses many food production chains, and herbicides participate in this process by eliminating weeds through different biochemical strategies. However, herbicides can affect non-target organisms such as bacteria, which can suffer damage if there is no efficient control of reactive oxygen species. It is not clear, according to the literature, whether the efficiency of this control needs to be selected by the presence of xenobiotics. Thus, the Pseudomonas sp. CMA 6.9 strain, collected from biofilms in an herbicide packaging washing tank, was selected for its tolerance to pesticides and analyzed for activities of different antioxidative enzymes against the herbicides Boral®, absent at the isolation site, and Heat®, present at the site; both herbicides have the same mode of action, the inhibition of the enzyme protoporphyrinogen oxidase. The strain showed tolerance to both herbicides in doses up to 45 times than those applied in agriculture. The toxicity of these herbicides, which is greater for Boral®, was assessed by means of oxidative stress indicators, growth kinetics, viability, and amounts of peroxide and malondialdehyde. However, the studied strain showed two characteristic antioxidant response systems for each herbicide: glutathione-s-transferase acting to control malondialdehyde in treatments with Boral®; and catalase, ascorbate peroxidase, and guaiacol peroxidase in the control of peroxide induced by Heat®. It is possible that this modulation of the activity of different enzymes independent of previous selection characterizes a system of metabolic plasticity that may be more general in the adaptation of microorganisms in soil and water environments subjected to chemical contaminants. This is relevant to the impact of pesticides on the diversity and abundance of microbial species as well as a promising line of metabolic studies in microbial consortia for use in bioremediation.

Avaliação de isolados de Staphylococcus aureus provenientes de carne bovina moída comercializada no oeste de Santa Catarina / Evaluation of Staphylococcus aureus isolates from bovine meat marketed west in Santa Catarina

Objetivo: Staphylococcus aureus tem sido reportado em surtos de origem alimentar em diversos lugares no mundo devido a expressões de variados fatores de virulência que causam injúrias no organismo humano, e, em Santa Catarina, entre 2012 a 2016, foi o segundo agente infeccioso que mais ocasionou surtos alimentares. O objetivo deste trabalho foi avaliar a presença de S. aureus em amostras de carne bovina moída da cidade de Xaxim- Santa Catarina, verificar a expressão de enzimas proteolíticas e lipolíticas, bem como a sensibilidade frente a diferentes antimicrobianos. Métodos: O isolamento do microrganismo foi realizado em ágar Baird-Paked. Os fatores de virulência foram determinados com a utilização de ágar Skim milk e ágar BHI enriquecido com óleo. A metodologia de disco-difusão foi utilizada para realização do antibiograma. Resultados: Os resultados obtidos demonstraram que, das 12 amostras coletadas, 10 estavam contaminadas com S. aureus com contagens acima do permitido pela legislação vigente. A expressão de enzimas proteolíticas foi verificada em 40% dos isolados na primeira coleta. Na coleta subsequente, todos os isolados obtiveram resultados positivos. Contudo, os isolados não demonstraram resultados em relação à expressão de enzimas lipolíticas. Na avaliação da sensibilidade aos antimicrobianos, a maior suscetibilidade foi evidenciada aos antibióticos tetraciclina e gentamicina. Em relação à penicilina, rifampicina e eritromicina foram verificadas porcentagens variadas de resistência. Conclusão: Os resultados demonstraram que os alimentos encontravam-se impróprios para o consumo, e, além disso, a capacidade de produção de proteases e a resistência antimicrobiana apresentada podem aumentar as chances de danos à saúde do consumidor.

Anatomy of a Neotropical insect radiation.

BACKGROUND: Much evolutionary theory predicts that diversity arises via both adaptive radiation (diversification driven by selection against niche-overlap within communities) and divergence of geographically isolated populations. We focus on tropical fruit flies (Blepharoneura, Tephritidae) that reveal unexpected patterns of niche-overlap within local communities. Throughout the Neotropics, multiple sympatric non-interbreeding populations often share the same highly specialized patterns of host use (e.g., flies are specialists on flowers of a single gender of a single species of host plants). Lineage through time (LTT) plots can help distinguish patterns of diversification consistent with ecologically limited adaptive radiation from those predicted by ecologically neutral theories. Here, we use a time-calibrated phylogeny of Blepharoneura to test the hypothesis that patterns of Blepharoneura diversification are consistent with an "ecologically neutral" model of diversification that predicts that diversification is primarily a function of time and space. RESULTS: The Blepharoneura phylogeny showed more cladogenic divergence associated with geography than with shifts in host-use. Shifts in host-use were associated with ~ 20% of recent splits (< 3 Ma), but > 60% of older splits (> 3 Ma). In the overall tree, gamma statistic and maximum likelihood model fitting showed no evidence of diversification rate changes though there was a weak signature of slowing diversification rate in one of the component clades. CONCLUSIONS: Overall patterns of Blepharoneura diversity are inconsistent with a traditional explanation of adaptive radiation involving decreases in diversification rates associated with niche-overlap. Sister lineages usually use the same host-species and host-parts, and multiple non-interbreeding sympatric populations regularly co-occur on the same hosts. We suggest that most lineage origins (phylogenetic splits) occur in allopatry, usually without shifts in host-use, and that subsequent dispersal results in assembly of communities composed of multiple sympatric non-interbreeding populations of flies that share the same hosts.

Evaluation antibacterial and antibiofilm activity of the antimicrobial peptide P34 against Staphylococcus aureus and Enterococcus faecalis

ABSTRACT The adhesion ability of bacteria to abiotic surfaces has important implications in food industries, because these organisms can survive for long periods through the biofilm formation. They can be transferred from one place to another in the industry causing contamination of the food processing environment. In this study, the antibacterial and antibiofilm activities of the antimicrobial peptide P34, characterized as a bacteriocin-like substance (BLS P34) were tested against planktonic and sessile cells of Staphylococcus aureus and Enterococcus faecalis isolated from foods. The BLS P34 showed inhibitory effect against all planktonic cells of E. faecalis. The inhibition of biofilm formation and the eradication of pre-formed biofilm were evaluated with the crystal violet assay and with the reduction of 3-bromide [4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium. The BLS P34 promoted a reduction of percentage of adhered microbial cells on the surface, not being able to perform the complete elimination of biofilm formation. The metabolic activity of S. aureus biofilms decreased considerably between 41-95%. However, E. faecalis cells showed up metabolically stimulated. The BLS P34 has the potential antibiofilm for the species S. aureus. Studies suggest more detailed approaches to a better understanding of the interactions between the antimicrobial and bacterial cells within the biofilm structure.

Evaluation antibacterial and antibiofilm activity of the antimicrobial peptide P34 against Staphylococcus aureus and Enterococcus faecalis.

The adhesion ability of bacteria to abiotic surfaces has important implications in food industries, because these organisms can survive for long periods through the biofilm formation. They can be transferred from one place to another in the industry causing contamination of the food processing environment. In this study, the antibacterial and antibiofilm activities of the antimicrobial peptide P34, characterized as a bacteriocin-like substance (BLS P34) were tested against planktonic and sessile cells of Staphylococcus aureus and Enterococcus faecalis isolated from foods. The BLS P34 showed inhibitory effect against all planktonic cells of E. faecalis. The inhibition of biofilm formation and the eradication of pre-formed biofilm were evaluated with the crystal violet assay and with the reduction of 3-bromide [4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium. The BLS P34 promoted a reduction of percentage of adhered microbial cells on the surface, not being able to perform the complete elimination of biofilm formation. The metabolic activity of S. aureus biofilms decreased considerably between 41-95%. However, E. faecalis cells showed up metabolically stimulated. The BLS P34 has the potential antibiofilm for the species S. aureus. Studies suggest more detailed approaches to a better understanding of the interactions between the antimicrobial and bacterial cells within the biofilm structure.

Microbial contamination in industrial tofu / Contaminação microbiana em tofu industrial

ABSTRACT: This study aimed to evaluate the microbiological quality of tofu sold in supermarkets in Porto Alegre/Brazil. Bacteria counts were performed for Bacillus cereus , mesophilic, coliforms and Staphylococcus coagulase positive and negative. The presence of Listeria sp. was also evaluated. Two different brands of tofu (A and B) were collected, one lot per month, for six months. Five samples from each lot were analyzed. All lots presented mesophilic aerobic counts above 4.3x105CFU g-1. Four of the six lots from brand A and all lots from brand B showed E. coli and/or Staphylococcus coagulase positive counts above the Brazilian law accepted limits. The Staphylococcus coagulase negative counts were higher than those of coagulase positive in all lots. In all lots where Staphylococcus coagulase positive counts were above the legal limit, there were counts of coagulase negative above 104CFU g-1. B. cereus and Listeria sp. were not found in either brand. The majority of lots of brand A and all lots of brand B were unsuitable for human consumption. Our results showed that there are problems in tofu manufacturing in both industries analyzed. There is a need of improvement on its microbial quality to avoid problems of food-borne illness, and finally the need of a better control by the Brazilian inspection services.

RESUMO: Este estudo teve como objetivo avaliar a qualidade microbiológica de queijo tofu comercializados em um supermercado da cidade de Porto Alegre, RS. Foram realizadas contagens de Bacillus cereus , bactérias mesófilas, coliformes, Staphylococcus coagulase positive e negativo e, a pesquisa de Listeria sp. Foi realizada a coleta de duas diferentes marcas (A e B), com um lote por mês, durante seis meses; sendo analisadas cinco amostras de cada lote. Todos os lotes apresentaram contagens de mesófilos aeróbios acima de 4,3x105UFC g-1. Quatro dos seis lotes da marca A e todos os lotes da marca B apresentaram contagens de E. coli e/ou Staphylococcus coagulase positive acima do permitido pela legislação vigente. As contagens de Staphylococcus coagulase negativos foram superiores às contagens dos coagulase positivos em todos os lotes. Nos lotes em que foram encontradas contagens fora do padrão estabelecido para os Staphylococcus coagulase positivos, havia contagens dos coagulase negativos acima de 104UFC g-1. Não foram isolados B. cereus e Listeria sp. Ambas as marcas apresentaram sérios problemas sanitários, pois a maioria dos lotes da marca A e todos os lotes da marca B estavam impróprios para o consumo mesmo na ausência dos outros patógenos pesquisados. Nossos resultados mostram que há problemas sérios na produção de tofu em ambas as indústrias analisadas. Existe a necessidade de melhorias no sistema de produção para evitar a ocorrência de doenças causadas por este alimento e, também, que deve haver um maior controle da qualidade deste alimento pelos serviços de fiscalização.

Activity of the antimicrobial peptide P34 against bovine alphaherpesvirus type 1 / Atividade do peptídeo antimicrobiano P34 contra o alfaherpesvírus bovino tipo 1

ABSTRACT: Previous studies have demonstrated the antimicrobial activity of the peptide P34. In this study, the antiviral potential of P34 and the in vitro mechanism of action were investigated against bovine alphaherpesvirus type 1 (BoHV1). P34 exhibited low toxicity, a high selectivity index (22.9) and a percentage of inhibition of up to 100% in MDBK cells. Results from antiviral assays indicated that P34 did not interact with cell receptors, but it was able to inhibit the viral penetration immediately after pre-adsorption. In addition, BoHV1 growth curve in MDBK cells in the presence of P34 revealed a significant reduction in virus titer only 8h post-infection, also suggesting an important role at late stages of the replicative cycle. Virucidal effect was observed only in cytotoxic concentrations of the peptide. These findings showed that the antimicrobial peptide P34 may be considered as a potential novel inhibitor of in vitro herpesviruses and must encourage further investigation of its antiherpetic activity in animal models as well as against a wide spectrum of viruses.

RESUMO: A atividade antimicrobiana do peptídeo P34 já foi previamente demonstrada. Neste estudo, o potencial antiviral do P34 e o mecanismo de ação in vitro contra o alfaherpesvírus bovino tipo 1 (BoHV1) foram investigados. O P34 exibiu baixa toxicidade, alto índice de seletividade (22.9) e percentagem de inibição viral de até 100% em células MDBK. Os resultados dos ensaios antivirais indicaram que não interage com receptores celulares, mas é capaz de inibir a penetração viral, imediatamente após a pré-adsorção. Além disso, a curva de crescimento do BoHV1 em células MDBK na presença do P34 revelou uma significativa redução no título somente após 8h de infecção, sugerindo também uma importante atividade do peptídeo nas fases finais do ciclo replicativo. Efeito virucida frente / BoHV1 foi observado apenas em concentrações citotóxicas do peptídeo. Os dados obtidos indicam que o peptídeo antimicrobiano P34 pode ser considerado um potencial composto inibidor de herpesvírus, in vitro, e estimulam posteriores investigações sobre sua atividade anti-herpética em modelos animais, bem como contra outros vírus.

Quantificação e identificação de Candida na cavidade oral de crianças / Quantification and identification of Candida in the oral cavity children

A identificação correta e precisa do agente causal de uma candidose é importante para a caracterização epidemiológica do tipo de infecção, como também para a escolha do tratamento. Os objetivos deste trabalho foram isolar, quantificar e identificar asleveduras do gênero Candida, presentes na cavidade oral de crianças de 2 a 4 anos de idade. Para a realização deste trabalho foram feitas coletas semanais em um grupo formado por dez crianças de 2 a 4 anos de idade, com o auxílio de swabs estéreis, friccionados na região periodental. O material coletado foi inoculado em meio cromogênico, utilizando-se a técnica de esgotamento e incubado a 36oC. A quantificação e identificação seguiram a metodologia descrita por Gwendolyn. Os resultados mostraram que, em 2.256 colônias isoladas, a C. albicans foi a mais frequente com 70,00; 70,44 e 95,15%, seguido pela C. tropicalis, com 16,99; 13,85 e 4,65%, C. glabrata com 11,77; 4,98 e 0,20%, respectivamente para 2, 3 e 4 anos de idade. A espécie que apresentou menor frequência foi a C. krusei com 1,24 e 10,73%, para 2 e 3 anos. Em crianças de 4 anos, não se verificou a presença dessa espécie .

The correct and precise identification of the causative agent of thrush is important for epidemiological characterization of the type of infection, but also for the choice of treatment. The objectives of this work was to isolate and quantify identify yeasts of the genus Candida in the oral cavity of children 2 to 4 years of age. For this work, samples were collected weekly in a group of ten children from 2 to 4 years old, and the samples were taken with sterile swabs, which were rubbed on the periodontal region. The collected material was inoculated on chromogenic medium, using the technique of exhaustion and incubated to 36 C. The quantification and identification followed the methodology described by Gwendolyn, (2005).The results showed that in 2256 isolated colonies, C.albicans was the most frequent with 70.00, 70.44 and 95.15%, followed by C. tropicalis, with 16.99, 13.85 and 4.65%, C. glabrata with 11.77, 4.98 and 0.20% respectively for 2, 3 and 4 years of age. The species that showed a lower frequency was C. krusei with 1.24and 10.73% for 2 and 3 years. In children aged 4 years, there was the presence of this species .