The common bean is one of the most important legumes in the human diet, but little is known about the endophytic bacteria associated with the leaves of this plant. The objective of this study was to characterize the culturable endophytic bacteria of common bean (Phaseolus vulgaris. leaves from three different cultivars (Vermelhinho, Talismã, and Ouro Negro) grown under the same field conditions. The density of endophytic populations varied from 4.5 x 10² to 2.8 x 10³ CFU g-1 of fresh weight. Of the 158 total isolates, 36.7% belonged to the Proteobacteria, 32.9% to Firmicutes, 29.7% to Actinobacteria, and 0.6% to Bacteroidetes. The three P. vulgaris cultivars showed class distribution differences among Actinobacteria, Alphaproteobacteria and Bacilli. Based on 16S rDNA sequences, 23 different genera were isolated comprising bacteria commonly associated with soil and plants. The genera Bacillus, Delftia, Methylobacterium, Microbacterium, Paenibacillus, Staphylococcus and Stenotrophomonas were isolated from all three cultivars. To access and compare the community structure, diversity indices were calculated. The isolates from the Talismã cultivar were less diverse than the isolates derived from the other two cultivars. The results of this work indicate that the cultivar of the plant may contribute to the structure of the endophytic community associated with the common bean. This is the first report of endophytic bacteria from the leaves of P. vulgaris cultivars. Future studies will determine the potential application of these isolates in biological control, growth promotion and enzyme production for biotechnology.

Com o objetivo de avaliar níveis de lactose em rações para leitões desmamados aos 21 dias de idade, foi realizado um experimento com 72 animais com peso inicial médio de 6,10 kg, distribuídos em delineamento de blocos ao acaso com quatro rações (0, 4, 8 e 12% de lactose), seis repetições e três animais por unidade experimental. Os animais foram alimentados com as rações experimentais no período de 21 a 35 dias de idade e, no período de 36 a 49 dias, receberam uma ração basal isenta de lactose. Os níveis de lactose não afetaram o ganho diário de peso, o consumo diário de ração e a conversão alimentar dos leitões de 21 a 35 dias. O uso de lactose nas rações também não afetou o desempenho dos leitões avaliados dos 21 aos 49 dias de idade. As rações também não influenciaram a altura das vilosidades, a profundidade de criptas e a relação vilosidade:cripta. A lactose proporcionou maior diversidade e equilíbrio da comunidade microbiana intestinal. A riqueza microbiana de Lactobacillus spp. aumenta com a adição de lactose na ração até o nível de 8% em relação ao número total de microrganismos intestinais, o que indica possível melhora da saúde intestinal.

With the objective of evaluating levels of lactose in diets for piglets weaned at 21 days of age, it was carried out an experiment with 72 animals, with average weight of 6.12 kg, distributed in a completely randomized block design with four diets (0, 4, 8, and 12% lactose), six replicates, and 3 animals per experimental unit. Animals were fed the experimental diets from 21 to 35 days of age and they were fed a lactose-free basal diet from 36 to 49 days of age. The lactose levels did not affect daily weight gain, feed intake and feed conversion of piglets from 21 to 35 days of age. The use of lactose levels in the diets also did not affect performance of the piglets assessed from 21 to 49 days old. Diets also did not influence villous height, crypt depth and villous:crypt ratio. Lactose resulted in greater diversity and balance of the intestinal microbial community. The Lactobalillus spp. richness increases with the addition of lactose in diet up to the level of 8% in relation to the total number of intestinal microorganisms, which may a possible improvement of intestinal health.

O crescimento de Salmonella enterica subs. enterica sorovar Typhimurium a 25°C foi determinado em dietas enterais industrializadas e formuladas em hospital e os resultados obtidos foram usados para validar um modelo matemático de crescimento de Salmonella apresentado no Programa de Modelagem de Patógenos (PMP), versão 7,0 (USDA-EUA). O tempo de geração de Salmonella em dietas enterais variou de 21 a 34,8 min e a velocidade específica máxima de crescimento (µmax) foi de 1,28 a 1,95 h-1, resultando em aumento de 5 a 6 ciclos logarítimos em um período de 14 a 24 h de incubação. O crescimento foi mais rápido na dieta formulada em hospital contendo vegetais e ovos. Os parâmetros cinéticos como fase lag, µmax e densidade populacional máxima (MDP) foram similares aqueles previstos no PMP 7.0, com exceção da fase lag em dietas enteral com pH 6,3. Os resultados deste estudo validaram o modelo do PMP 7,0 para descrever o crescimento de Salmonella em dietas enterais e demonstraram a propriedade desse modelo para determinar o comportamento do patógeno em uma variedade de condições nesse tipo de alimento.

The growth of Salmonella enterica subs. enterica sorovar Typhimurium at 25°C was monitored in industrialized and hospital formulated enteral feeds and the results were used to validate the mathematical model of Salmonella growth presented by the Pathogen Modeling Program (PMP) 7.0 (USDA-USA). The generation time of Salmonella in enteral feeds ranged from 21 to 34.8 min and, the maximum growth rate (µmax) varied from 1.28 to 1.95 h-1, resulting in a population increase from 5 to 6 log10 cycles within 14 to 24 h incubation. Growth was faster in the hospital formulated feed containing vegetables and eggs. The growth kinetic's parameters as lag phase; µmax and maximum population density (MPD) were similar to those predicted by the PMP 7.0, with exception of lag phase in enteral diet at pH 6.3. The results of this study validated the PMP 7.0 model for describe Salmonella growth in enteral feeds and demonstrates the appropriateness of use such model to determine the pathogen behavior in a wide range of storage conditions in this food.

Operons ribossomais têm sido instrumentos importantes na caracterização de comunidades microbianas e no estudo de relacionamentos entre microrganismos, principalmente em bactérias do ácido láctico. Operons ribossomais da linhagem probiótica, Lactobacillus delbrueckii UFV H2b20, foram parcialmente caracterizados. Um banco genômico da linhagem foi construído e os clones, contendo parte do operon ribossomal, foram subclonados pelo método de "shot gun", para em seguida serem seqüenciados com primer "forward". As seqüências indicaram a presença da extremidade 3' do rDNA 16S seguida da região espaçadora curta 1 (16S-23S) e a presença da extremidade 3' do rDNA 23S seguido da região espaçadora 2 (23S-5S), que por sua vez precedia o rDNA 5S. Adjacente ao gene rDNA 5S deste operon rrn uma região codificadora de 6 tRNAs foi detectada.

Ribosomal operons are great tools for microbe community characterization and for microorganisms relationship study, particularly in the case of the acid lactic bacteria. The ribosomal operon of the probiotic strain Lactobacillus delbrueckii UFV H2b20 was partially characterized. A genomic library of this strain was constructed and the clones with partial ribosomal operon were sub-cloned using the shot-gun method for subsequent sequencing with the forward primer. The sequence analysis revealed that the 3' end of the rDNA 16S was following by the short spacer region 1 (16S-23S) and that the 3' end of the rDNA 23S was following by the short spacer region 2 (23S-5S), which preceded the rDNA 5S. In the flanking region of the rDNA 5S gene of this operon rrn, a region encoding six tRNAs was detected.

Multidrug efflux mechanisms in bacteria contribute significantly to intrinsic and acquired resistance to antimicrobial agents. Genome analysis have confirmed the broad distribution of these systems in Gram-negative as well as in Gram-positive bacteria. Among resistance mechanisms, the multidrug efflux system or pump deserves special attention, since a cell that has acquired it can simultaneously diminish or even suppress the susceptibility to a wide range of antimicrobials. The efflux system is mediated by transport proteins which confer resistance to toxic compounds. In Gram-negative bacteria, a tripartite efflux system is necessary to expel the drug to the outer medium: a protein localized in the cytoplasmic membrane; another in the periplasmatic space (membrane fusion protein - MFP); and a third in the outer membrane (outer membrane factor - OMF). The drug transport is active, and depends either on the energy provided by ATP hydrolysis or is directly driven by the proton motive force. The transport proteins are grouped in families, according to the homology of the amino acid sequences and to similarity of mechanisms. Among Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa have most of the hitherto identified and studied multidrug efflux systems.

Bactérias láticas foram isoladas durante o processamento de salame tipo italiano, obtido a partir de duas plantas de processamento, no Estado do Paraná. Para o isolamento, foram utilizados os meios MRS, D-MRS e M17. Um total de 484 isolados teve sua atividade antibacteriana testada sobre Listeria monocytogenes (Laboratório de Microbiologia - UFV), Staphylococcus aureus (ATCC 25923), Salmonella enteritidis (ATCC 13076) e Escherichia coli (ATCC 25922), utilizando-se o deferred method. Cento e quinze isolados apresentaram zonas de inibição sobre, pelo menos, duas das bactérias indicadoras. Os isolados apresentaram maior inibição sobre Listeria monocytogenes. Os 45 isolados que apresentaram zonas de inibição sobre as quatro bactérias indicadoras foram identificados, utilizando-se o sistema Biolog. Lactobacillus bifermentans predominou entre os isolados identificados, obtidos no meio MRS, a partir das amostras das duas plantas de processamento.

Lactic acid bacteria were isolated in the MRS, D-MRS and M17 modified media, during the processing of Italian salami, obtained from two processing plants, in the State of Paraná. The 484 isolates were tested for their antibacterial activity against Listeria monocytogenes (Microbiology Laboratory-UFV), Staphylococcus aureus (ATCC 25923), Salmonella enteritidis (ATCC 13076) and Escherichia coli (ATCC 25922), by a deferred method. One hundred and fifteen isolates inhibited at least two of the pathogens. The isolates presented larger inhibition against L. monocytogenes. The 45 isolates with antagonistic action on the four indicator bacteria were identified by the system Biolog. Lactobacillus bifermentans prevailed among the isolates identified in MRS medium from the samples of the two processing plants.