Genes involved in lactose catabolism and organic acid production during growth of Lactobacillus delbrueckii UFV H2b20 in skimmed milk.

There are three main reasons for using lactic acid bacteria (LAB) as starter cultures in industrial food fermentation processes: food preservation due to lactic acid production; flavour formation due to a range of organic molecules derived from sugar, lipid and protein catabolism; and probiotic properties attributed to some strains of LAB, mainly of lactobacilli. The aim of this study was to identify some genes involved in lactose metabolism of the probiotic Lactobacillus delbrueckii UFV H2b20, and analyse its organic acid production during growth in skimmed milk. The following genes were identified, encoding the respective enzymes: ldh - lactate dehydrogenase, adhE - Ldb1707 acetaldehyde dehydrogenase, and ccpA-pepR1 - catabolite control protein A. It was observed that L. delbrueckii UFV H2b20 cultivated in different media has the unexpected ability to catabolyse galactose, and to produce high amounts of succinic acid, which was absent in the beginning, raising doubts about the subspecies in question. The phylogenetic analyses showed that this strain can be compared physiologically to L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis, which are able to degrade lactose and can grow in milk. L. delbrueckii UFV H2b20 sequences have grouped with L. delbrueckii subsp. bulgaricus ATCC 11842 and L. delbrueckii subsp. bulgaricus ATCC BAA-365, strengthening the classification of this probiotic strain in the NCFM group proposed by a previous study. Additionally, L. delbrueckii UFV H2b20 presented an evolutionary pattern closer to that of probiotic Lactobacillus acidophilus NCFM, corroborating the suggestion that this strain might be considered as a new and unusual subspecies among L. delbrueckii subspecies, the first one identified as a probiotic. In addition, its unusual ability to metabolise galactose, which was significantly consumed in the fermentation medium, might be exploited to produce low-browning probiotic Mozzarella cheeses, a desirable property for pizza cheeses.

Eficácia e toxicidade do pó comercial de Hoodia gordonii (Masson) swet ex decne utilizado no tratamento da obesidade / Efficacy and toxicity of Hoodia gordonii commercial powder used to combat obesity

A obesidade é atualmente o principal problema de saúde em países desenvolvidos e em desenvolvimento. Diversos recursos terapêuticos têm sido empregados para o tratamento da obesidade destacando-se os fitoterápicos, consagrados pelo conhecimento popular. Nesse contexto, a planta Hoodia gordonii tem despertado atualmente grande interesse mundial, principalmente pelas recentes descobertas e comprovações científicas da inibição do apetite e da sede pelo glicosídeo ativo P57 isolado de espécies da planta. Apesar disso, tais efeitos ainda não foram avaliados e comprovados em amostras comerciais do pó de H. gordonii (PHG), não existindo evidências científicas que garantam a sua eficácia e segurança. Portanto, o objetivo deste trabalho foi realizar ensaios biológicos com ratos para avaliar a atividade farmacológica e a toxicidade de amostras comerciais do pó de H. gordonii. As amostras foram administradas por gavagem em doses equivalentes a 20 vezes as recomendadas para humanos em ratas Wistar durante 4 semanas sendo avaliados os parâmetros indicadores do efeito terapêutico. Após as 4 semanas, os animais foram sacrificados, e amostras de sangue e órgãos foram coletados e submetidos à avaliação dos indicadores metabólicos, endócrinos, hematológicos e histopatológicos. Os resultados demonstraram que para todos os parâmetros avaliados não houve diferenças significativas entre o grupo controle que recebeu somente solução salina estéril e os grupos tratados com PHG indicando que os mesmos, apesar de não apresentarem quaisquer indícios de toxicidade, são incapazes de produzir os supostos efeitos de inibição de apetite e consequente tratamento da obesidade.

Obesity is currently the main health problem in developed and developing countries. Several therapeutic methods have been employed for the treatment of obesity, especially herbal medicines, highlighted by popular knowledge. In this context, the plant Hoodia gordonii has currently aroused great interest worldwide, especially for recent discoveries and scientific proof of inhibition of appetite and thirst by the active glycoside P57 isolated from plant species. Nevertheless, such effects have not been evaluated and proven for commercial samples of H. gordonii powder (PHG), with no scientific evidence to ensure its effectiveness and safety. Therefore, the aim of this study was to conduct biological tests with rats to evaluate the pharmacological activity and toxicity of commercial samples of H. gordonii powder. The samples were administered through gavage, at doses equivalent to 20 times those recommended for humans, in female Wistar rats during 4 weeks for evaluation of the parameters indicative of therapeutic efficacy. After 4 weeks, the animals were sacrificed and blood and organ samples were collected and subjected to the evaluation of metabolic, endocrine, hematological and histopathological indicators. Results showed that for all evaluated parameters, there were no significant differences between the control group that only received sterile saline solution and the groups treated with PHG, indicating that the latter, although presenting no evidence of toxicity, are unable to produce the alleged effects of appetite inhibition and subsequent obesity treatment.

Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria / Atividade antibacteriana de extratos de plantas do Brasil contra bactérias patogênicas para peixes

The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity.

O objetivo deste trabalho foi avaliar a atividade antibacteriana de extratos de plantas brasileiras contra bactérias patogênicas para peixes. A atividade antibacteriana de quarenta e seis extratos metanólicos de plantas foi avaliada contra os agentes Streptococcus agalactiae, Flavobacterium columnare e Aeromonas hydrophila. Trinta e um extratos apresentaram atividade antibacteriana.

Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria.

The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity.

Inhibition of lymphocyte activation by extracts and fractions of Kalanchoe, Alternanthera, Paullinia and Mikania species.

Aqueous or ethanol extracts obtained from the leaves of Mikania glomerata (Asteraceae) and different species of Kalanchoe (Crassulaceae) or Alternanthera (Amaranthaceae) and from seeds of Paullinia cupana (Sapindaceae) blocked the capacity of human lymphocytes to proliferate in vitro. In all cases, a proliferative response induced by cocultivation of lymphocytes with phytohemagglutinin was inhibited even after depletion of phagocytic mononuclear cells by adherence. A flavonoid-enriched fraction from K. pinnata and an ethyl acetate fraction from A. tenella were 10 to 20-fold, respectively, more potent in inhibiting lymphocyte proliferation than their original crude extracts. In contrast, these fractions had no inhibitory action on human natural killer activity. Lymphocyte suppression by the extracts was not due to a cytotoxic effect. Pre-incubation with the highest extract concentrations did not affect the capacity of lymphocytes to proliferate, after removal of extracts from the medium. These results indicate a direct action of the extracts on lymphocytes. They also suggest that these medicinal plants may contain potential immunosuppressive substances that selectively act on activation steps of the cells of the immune system.