Virulência e formação de biofilme microbiano por Enterococcus faecalis isolados de swabs cloacais de frangos de corte infectados com Eimeria spp

A dinâmica da microbiota no trato gastrointestinal (TG) de animais pode ser afetada por patógenos, tais como Eimeria spp. Os enterococos são bactérias saprófitas que colonizam o TG de mamíferos e aves. A influência sobre a microbiota intestinal está relacionada com a capacidade de adaptação das bactérias em se aderir às células hospedeiras e de colonizar as células das mucosas. O objetivo deste estudo foi analisar a frequência de genes de virulência ace, agg e operon do bopABCD em Enterococcus faecalis isolados de swabs cloacais de frangos de corte desafiados com Eimeria spp e alimentados com dietas padrões suplementadas ou não com anticoccidiano (monesina) e também avaliar a capacidade dessas cepas em formar biofilmes sob condições in vitro. Um total de 70 E. faecalis foram selecionadas e o gene agg foi mais freqüente em cepas isoladas de frangos de corte alimentados com anticoccidiano (92,3%) quando comparado ao grupo que não recebeu anticoccidiano (70,5%). Por outro lado, os genes ace e do operon bopABCD não demostraram nenhuma diferença significativa entre os dois grupos de frangos (P>0,005). Os E. faecalis isolados de frangos de corte alimentados com anticoccidiano demostraram uma maior frequência de fortes aderentes quando crescendo em meio suplementado com glicose (92,3-88,5%) e urina (77%), quando comparado com enterococos isolados de frangos que não receberam anticoccidiano. Observou-se que E. faecalis isolados de frangos tratados com anticoccidiano mostraram uma maior frequêencia dos genes dos fatores de virulência e de perfil de fortes formadores de biofilme, o que indica uma melhor adaptação dos isolados em ambiente intestinal saudável

Differential expression of cysteine desulfurases in soybean

<p>Abstract</p> <p>Background</p> <p>Iron-sulfur [Fe-S] clusters are prosthetic groups required to sustain fundamental life processes including electron transfer, metabolic reactions, sensing, signaling, gene regulation and stabilization of protein structures. In plants, the biogenesis of Fe-S protein is compartmentalized and adapted to specific needs of the cell. Many environmental factors affect plant development and limit productivity and geographical distribution. The impact of these limiting factors is particularly relevant for major crops, such as soybean, which has worldwide economic importance.</p> <p>Results</p> <p>Here we analyze the transcriptional profile of the soybean cysteine desulfurases <it>NFS1</it>, <it>NFS2 </it>and <it>ISD11 </it>genes, involved in the biogenesis of [Fe-S] clusters, by quantitative RT-PCR. <it>NFS1</it>, <it>ISD11 </it>and <it>NFS2 </it>encoding two mitochondrial and one plastid located proteins, respectively, are duplicated and showed distinct transcript levels considering tissue and stress response. <it>NFS1 </it>and <it>ISD11 </it>are highly expressed in roots, whereas <it>NFS2 </it>showed no differential expression in tissues. Cold-treated plants showed a decrease in <it>NFS2 </it>and <it>ISD11 </it>transcript levels in roots, and an increased expression of <it>NFS1 </it>and <it>ISD11 </it>genes in leaves. Plants treated with salicylic acid exhibited increased <it>NFS1 </it>transcript levels in roots but lower levels in leaves. <it>In silico </it>analysis of promoter regions indicated the presence of different <it>cis</it>-elements in cysteine desulfurase genes, in good agreement with differential expression of each locus. Our data also showed that increasing of transcript levels of mitochondrial genes, <it>NFS1</it>/<it>ISD11</it>, are associated with higher activities of aldehyde oxidase and xanthine dehydrogenase, two cytosolic Fe-S proteins.</p> <p>Conclusions</p> <p>Our results suggest a relationship between gene expression pattern, biochemical effects, and transcription factor binding sites in promoter regions of cysteine desulfurase genes. Moreover, data show proportionality between <it>NFS1 </it>and <it>ISD11 </it>genes expression.</p

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

Diversity of Mutations in the atpC Gene Coding for the c Subunit of F0F1 ATPase in Clinical Isolates of Optochin-Resistant Streptococcus pneumoniae from Brazil▿

We report the characteristics of four optochin-resistant (Optr) Streptococcus pneumoniae isolates from Brazil. All four Optr isolates presented mutations in the nucleotide sequence coding for the c subunit of F0F1 ATPase. Two isolates showed mutations in codons 23 (leading to the deduced amino acid substitution isoleucine instead of alanine) and 49 (serine instead of alanine, a novel type of mutation detected at this position), respectively. Two additional novel mutations, both located in codon 45, were detected in the other two isolates, corresponding to leucine or valine (instead of phenylalanine). The data indicate that three previously unrecognized alterations were detected in the atpC gene of S. pneumoniae and that Opt resistance among Brazilian pneumococcal isolates is not related to a specific pneumococcal serotype, antimicrobial-resistance profile, or clonal group