Probiotics Bacillus toyonensis and Saccharomyces boulardii improve the vaccine immune response to Bovine herpesvirus type 5 in sheep.

There have been significant efforts toward the development of more efficient vaccines for animal health. A strategy that may be used to improve vaccine efficacy is the use of probiotics. Bovine herpesvirus 5 (BoHV-5) is an example of an important animal pathogen for which vaccines have provided only limited protection. In this study, we examined the use of the probiotics Bacillus toyonensis and Saccharomyces boulardii as a potential immune modulator to improve vaccine efficiency. Thirty, 5-month-old lambs were randomly grouped in three lots of 10 each and vaccinated at days 0, 21 and 42 of the experiment. They grazed on the same pasture and were fed ad libitum twice a day with commercial sheep feed supplemented with either B. toyonensis (1×106CFU/g of feed) or S. boulardii (1×107CFU/g of feed), or non-supplemented feed. The probiotic supplementation was suspended day 28; thereafter, the next 35days, they were fed with the same commercial feed as control group. Animals supplemented with probiotics showed a significant (p>0.001) increased seroconversions against BoHV-5, and higher neutralizing antibodies titres (p>0.05) to BoHV-5 than non-supplemented animals. At 63days of experiment, splenocytes from the supplemented sheep had higher mRNA transcription levels of cytokines IL-10 and IL-17A. These results suggest that these probiotics could provide a promising means of improving vaccine efficacy.

Inducers and autoinducers on Salmonella enterica serovar Typhimurium motility, growth and gene expression / Indutores e autoindutores na motilidade, no crescimento e na expressão gênica de Salmonella enterica serovar Typhimurium

Genus Salmonella bacteria are among the major pathogenic microorganisms in food. This bacterium pathogenicity is related to a number of virulence factors, among which its flagella. Flagellum expression is one of the virulence factors modulated by Quorum Sensing. Epinephrine produced by mammals uses the same signaling pathway of the 3 bacteria autoinducer. This study evaluated the effect of molecules inducer (epinephrine) and autoinducers (autoinducer 2 and autoinducer 3) and their association with the motility, growth and expression genes flhC, fliA, fliY, motA, motB e fliC of Salmonella Typhimurium (ST). Initially, ST was inoculated in BHI. Then, motility assays, growth curves and gene expression were performed by testing different concentrations of epinephrine (50, 125, 250, 500µM), conditioned medium (10 and 50%) and a combination of these. ST was exposed to different concentrations of epinephrine, conditioned medium and an association of both. Following, motility assays, bacterial growth and gene expression were performed. The results obtained showed that the combination of 500uM epinephrine with 50% conditioned medium increased ST bacterial motility by increasing the expression of genes involved in flagellum assembly.

Salmonella está entre os principais micro-organismos patogênicos veiculados por alimentos. A patogenicidade dessa bactéria está relacionada a uma série de fatores de virulência e, dentre estes, podemos citar os flagelos. A expressão do flagelo está entre os fatores de virulência modulados por Quorum Sensing. A adrenalina produzida pelos mamíferos utiliza a mesma via de sinalização do autoindutor 3 das bactérias. Nesse sentido, este trabalho teve como objetivo avaliar o efeito de moléculas indutora (adrenalina) e autoindutoras (auto-indutor 2 e auto-indutor 3) e a associação destas na motilidade, no crescimento celular e na expressão dos genes flhC, fliA, fliY, motA, motB e fliC de SalmonellaTyphimurium (ST). Inicialmente, ST foi semeada em caldo BHI. Após, ensaios de motilidade, curvas de crescimento e expressão gênica foram feitos, testando diferentes concentrações de adrenalina (50, 125, 250, 500µM), meio condicionado (10 e 50%) e a associação destes. A partir dos resultados obtidos, observou-se que o tratamento que utilizou 50% de meio condicionado + 500µM de adrenalina aumentou a motilidade de ST, em decorrência do aumento de genes envolvidos com montagem do flagelo.

The role of quorum sensing in Escherichia coli (ETEC) virulence factors.

Quorum sensing (QS) is a signaling system among bacteria mediated by auto-inducer substances (AI). Whenever the concentration of these molecules reaches a threshold corresponding to a high cell density or quorum, the whole population starts a coordinated expression of specific genes. Studies have shown that epinephrine is also responsible for activating specific bacterial genes. This work aimed to investigate the role of conditioned medium (containing AI), epinephrine and their association on growth, motility, F4 fimbriae and heat-labile toxin (LT) expression on enterotoxigenic Escherichia coli (ETEC, E68). A significant increase in motility, F4 and LT expression, was observed in the ETEC culture supplemented with conditioned medium and epinephrine. These findings suggest that ETEC uses some components of conditioned medium (e.g., AI molecules), host molecules (epinephrine), and their association to modulate the expression of important virulence genes.