Growth and antimicrobial activity of lactic acid bacteria from rumen fluid according to energy or nitrogen source

Objetivou-se avaliar os efeitos da suplementação com diferentes fontes de energia e de compostos nitrogenados sobre o crescimento e produção de bacteriocinas de bactérias ácido-láticas in vitro. As incubações foram conduzidas utilizando-se fluido ruminal originado de um novilho Holandês-Zebu fistulado no rúmen. O animal foi mantido em pastagem de Brachiaria decumbens recebendo 200 g/dia de proteína bruta suplementar. Os substratos e o inóculo foram acondicionados em frascos de vidro considerando-se oito tratamentos: celulose, celulose e caseína, celulose e peptona de soja, celulose e ureia, amido, amido e caseína, amido e peptona de soja e amido e ureia. Incubações sucessivas foram conduzidas para seleção dos microrganismos em função das fontes energéticas e de compostos nitrogenados. O amido favoreceu o crescimento de bactérias ácido-láticas em comparação à celulose. A suplementação com proteína verdadeira (peptona de soja e caseína) estimulou o crescimento dessas bactérias em comparação ao controle (sem suplementação com compostos nitrogenados). A adição de ureia não estimulou o crescimento de bactérias ácido-láticas. Nenhuma atividade antimicrobiana foi detectada a partir das colônias de bactérias ácido-láticas isoladas. Fontes de proteína verdadeira incrementam a competição entre bactérias fermentadoras de carboidratos estruturais e não-estruturais.

Susceptibility of Saccharomyces cerevisiae and lactic acid bacteria from the alcohol industry to several antimicrobial compounds

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of probiotic bacteria, isoflavones and simvastatin on lipid profile and atherosclerosis in cholesterol-fed rabbits: a randomized double-blind study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bottled mineral water as a potential source of antibiotic resistant bacteria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparative genomics analyses of citrus-associated bacteria

Xylella fastidiosa 9a5c (XF-9a5c) and Xanthomonas axonopodis pv. citri (XAC) are bacteria that infect citrus plants. Sequencing of the genomes of these strains is complete and comparative analyses are now under way with the genomes of other bacteria of the same genera. In this review, we present an overview of this comparative genomic work. We also present a detailed genomic comparison between XF-9a5a and XAC. Based on this analysis, genes and operons were identified that might be relevant for adaptation to citrus. XAC has two copies of a type II secretion system, a large number of cell wall-degrading enzymes and sugar transporters, a complete energy metabolism, a whole set of avirulence genes associated with a type III secretion system, and a complete flagellar and chemotatic system. By contrast, XF-9a5c possesses more genes involved with type IV pili biosynthesis than does XAC, contains genes encoding for production of colicins, and has 4 copies of Type I restriction/modification system while XAC has only one.

Presence of bacteria in dentinal tubules

This study demonstrated that a significant number of bacteria is present. in the radicular dentinal tubules of periodontally diseased human teeth. Ten periodontally diseased teeth were prepared and stained by Brown and Brenn technique for histological examination. Bacteria were detected in all teeth. It is suggested that bacteria may invade dentinal tubules exposed to periodontal pocket and are very hard to be eliminated by conventional mechanical and chemical periodontal therapy. Contaminated dentinal tubules of periodontally diseased teeth can thus act as active bacterial reservoirs to promote recolonization of mechanically treated root surfaces, which could interfere with the periodontal healing and progression of the disease.

Occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing head and neck radiotherapy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Occurrence of yeasts, enterococci and other enteric bacteria in subgingival biofilm of HIV-positive patients with chronic gingivitis and necrotizing periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of human dentine on the antibacterial activity of self-etching adhesive systems against cariogenic bacteria

Objectives: The incorporation of antibacterial agents into adhesive systems has been proposed to eliminate residual bacteria from dentine. This study used the agar diffusion method to evaluate the antibacterial activity of Clearfil Protect Bond (CPB), Clearfil SE Bond (CSEB), Clearfil Tri-S Bond (C3SB) and Xeno-III (XIII) self-etching adhesive systems, with or without light-activation, against cariogenic bacteria, and to assess the influence of human dentine on the antibacterial activity of these materials.Methods: An aliquot of 10 mu l per material (and individual components) were pipetted onto paper and dentine discs distributed in Petri dishes containing bacterial culture in BHI agar. Positive control was 0.2% chlorhexidine digluconate (CHX).Results: After incubation, the adhesive components of CPB and CSEB, liquid A of XIII and C3SB did not present antibacterial activity when applied to paper discs. The non-light-activated CPB primer + adhesive promoted the greatest inhibition of Streptococcus mutans (p < 0.05), whereas with light-activation, there was no significant difference between primer + adhesive and primer alone. For Lactobacillus acidophilus, CPB primer presented the greatest antibacterial activity in both light-activation conditions (p < 0.05). Regarding the dentine discs, only CHX promoted an inhibitory effect, though less intense than on paper discs (p < 0.05). CHX presented greater antibacterial activity against S. mutans than against L. acidophilus (p < 0.05).Conclusions: Light-activation significantly reduced the antibacterial activity of the self-etching adhesive systems; MDPB incorporation contributed to the effect of adhesive systems against cariogenic bacteria; the components eluted from the adhesive systems were not capable to diffuse through 400 mu m-thick dentine disc to exert their antibacterial activity against cariogenic bacteria. (C) 2008 Elsevier Ltd. All rights reserved.