RESUMO
PURPOSE OF WORK: To clone, express and characterize uroporphyrinogen III synthase/methyltransferase gene (cobA/hemD) from Lactobacillus reuteri. Some strains of Lb. reuteri produce cobalamin (vitamin B(12)). Cobalamin biosynthesis relies on the sequential action of more than 25 enzymes in a complex metabolic pathway. We have cloned, expressed and characterized the gene in Lb. reuteri that codes for the S-adenosy L: -methionine uroprophyrinogen III methyltransferase/synthase (CobA/HemD), a key bifunctional enzyme in the biosynthesis of cobalamin and other tetrapyrrols.
Assuntos
Limosilactobacillus reuteri/enzimologia , Metiltransferases/biossíntese , Metiltransferases/genética , Uroporfirinogênio III Sintetase/biossíntese , Uroporfirinogênio III Sintetase/genética , Sequência de Aminoácidos , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Sequência de Bases , Clonagem Molecular , Simulação por Computador , Escherichia coli/genética , Escherichia coli/metabolismo , Limosilactobacillus reuteri/genética , Metiltransferases/química , Dados de Sequência Molecular , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Espectrometria de Fluorescência , Uroporfirinogênio III Sintetase/químicaRESUMO
BACKGROUND: The aim of this study was to determine whether the consumption of soy product fermented with Enterococcus faecium CRL 183, would modify the fecal microbiota of rats fed a diet containing red meat. The rats were placed in groups, distinguished by their diets. For 60 days, group I was given a standard casein-based rodent feed and groups II-VI, the beef-based feed. From the 30th day, groups III-VI also ingested the following products: group III, E. faecium-fermented soy product; group IV, pure suspension of E. faecium; group V, sterilized fermented soy product; and group VI, unfermented soy product. RESULTS: Rats that ingested fermented soy product showed a slight increase in the numbers of lactobacilli (0.45 log CFU g(-1)), as did the casein-based diet group (0.47 log CFU g(-1)). The fermented soy product did not cause any reduction in the number of enterobacteria or clostridia, but promoted a slight fall in the viable count of Bacteroides spp. (2.80 +/- 0.20 to 2.34 +/- 0.07 log CFU g(-1)). CONCLUSIONS: The results indicate that the ingestion of this fermented soy product did not lead to significant changes in the fecal microbiota of the rats fed on a beef-based diet.
Assuntos
Bactérias/efeitos dos fármacos , Colo/microbiologia , Dieta , Fezes/microbiologia , Microbiologia de Alimentos , Carne , Leite de Soja/farmacologia , Animais , Bacteroides/efeitos dos fármacos , Caseínas , Bovinos , Clostridium/efeitos dos fármacos , Enterobacteriaceae/efeitos dos fármacos , Enterococcus faecium , Fermentação , Lactobacillus/efeitos dos fármacos , Masculino , Ratos , Ratos WistarRESUMO
BACKGROUND: There is increasing interest in natural treatments to control dyslipidemia and reduce the risk of cardiovascular disease. Previous studies have demonstrated the beneficial effects of soy yogurt fermented with Enterococcus faecium CRL 183 and of dietary isoflavones on the lipid profile. The purpose of the present study was to investigate the effects of isoflavone-supplemented soy yogurt, fermented with E. faecium CRL183, on lipid parameters and atherosclerosis development in rabbits with induced hypercholesterolemia. METHODS: Forty-eight rabbits were randomly assigned to eight groups fed on the following diets for 60 days: C - control; IY - isoflavone-supplemented soy yogurt; H - hypercholesterolemic (1.0% cholesterol wt/wt diet); HY - hypercholesterolemic plus soy yogurt; HIY - hypercholesterolemic plus isoflavone-supplemented soy yogurt; HP - hypercholesterolemic plus placebo; HI - hypercholesterolemic plus isoflavone and HE - hypercholesterolemic plus pure culture of E. faecium CRL 183. Serum lipids and autoantibodies against oxLDL (oxLDL Ab) were analyzed on days 0, 30 and 60 of the treatment and the atherosclerotic lesions were quantified at the end of the experiment. RESULTS: Soy yogurt, soy yogurt supplemented with isoflavones and placebo promoted significant reductions in total cholesterol level (38.1%, 27.0% and 26.6%, respectively). Significant increases in serum HDL-C concentration relative to group H were detected in animals that ingested soy yogurt, with or without the isoflavone supplement (55.2%), E. faecium culture (43.3%) or placebo (35.8%). Intake of soy yogurt and soy yogurt supplemented with isoflavones prevented the rise of oxLDL Ab during the study period. The extent of atherosclerosis in the thoracic and abdominal aortas was reduced in the HIY, HY and HP groups. However, when the whole aorta was analyzed, animals treated with soy yogurt supplemented with isoflavones exhibited the greatest reduction (51.4%, P < 0.05) in atherosclerotic lesion area, compared to group H. CONCLUSION: Soy yogurt could be consumed as an alternative means of reducing the risk of cardiovascular disease by improving the lipid profile and inhibiting oxLDL Ab formation. Our findings also suggest that isoflavone supplementation may enhance the antiatherosclerotic effect of soy yogurt.
Assuntos
Aterosclerose/prevenção & controle , Glycine max/química , Isoflavonas/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Iogurte , Animais , Aterosclerose/sangue , Aterosclerose/dietoterapia , Aterosclerose/tratamento farmacológico , Aterosclerose/patologia , Colesterol/sangue , LDL-Colesterol/sangue , Coelhos , Distribuição AleatóriaRESUMO
We found that Lactobacillus reuteri CRL1098, a lactic acid bacterium isolated from sourdough, is able to produce cobalamin. The sugar-glycerol cofermentation in vitamin B(12)-free medium showed that this strain was able to reduce glycerol through a well-known cobalamin-dependent reaction with the formation of 1,3-propanediol as a final product. The cell extract of L. reuteri corrected the coenzyme B12 requirement of Lactobacillus delbrueckii subsp. lactis ATCC 7830 and allowed the growth of Salmonella enterica serovar Typhimurium (metE cbiB) and Escherichia coli (metE) in minimal medium. Preliminary genetic studies of cobalamin biosynthesis genes from L. reuteri allowed the identification of cob genes which encode the CobA, CbiJ, and CbiK enzymes involved in the cobalamin pathway. The cobamide produced by L. reuteri, isolated in its cyanide form by using reverse-phase high-pressure liquid chromatography, showed a UV-visible spectrum identical to that of standard cyanocobalamin (vitamin B12).
Assuntos
Proteínas de Bactérias , Lactobacillus/metabolismo , Vitamina B 12/biossíntese , Alquil e Aril Transferases/genética , Alquil e Aril Transferases/metabolismo , Metabolismo dos Carboidratos , Cromatografia Líquida de Alta Pressão/métodos , Cianetos/química , Fermentação , Genes Bacterianos , Glicerol/metabolismo , Lactobacillus/genética , Espectrofotometria Ultravioleta , Vitamina B 12/análise , Vitamina B 12/isolamento & purificaçãoRESUMO
OBJECTIVE: To assess the effect of a new feed soy product fermented by Enterococcus faecium and Lactobacillus jugurti on the serum lipid levels of rabbits with induced hypercholesterolemia. METHODS: Thirty-two rabbits were divided into 4 groups as follows: 1) control (C); 2) hypercholesterolemic (H); 3) hypercholesterolemic + fermented product (HPF); and 4) control + fermented product (CPF). The H and HPF groups were fed with a diet with 0.15 per cent (p/p) cholesterol in the first 15 days. C and CPF groups received regular food preparation. The HPF and CPF groups received 10 mL daily of the fermented 30 days. Blood samples were drawn at the beginning of the study and at the 15th and 30th days. Concentrations of total cholesterol, HDL-cholesterol, and triglycerides were analyzed. RESULTS: After 15 days, the HPF group showed a total cholesterol concentration lower (18.4 per cent) than that of the H group (p=0.05), but this difference disappeared after 30 days. No change was observed in total cholesterol levels of C and CPF groups. After 15 days, the HDL-cholesterol was higher (17.8 per cent) in the HPF group, but the triglyceride levels remained unchanged in all groups during the same period of time. CONCLUSION: The soy fermented product caused an 18.4 per cent reduction in total cholesterol and a 17.8 per cent increase in the HDL-fraction. It may, therefore, be a possible coadjutor in the treatment of hypercholesterolemia.
Assuntos
Animais , Masculino , Coelhos , Hipercolesterolemia/metabolismo , Lipídeos/sangue , Glycine max/efeitos adversos , Colesterol/sangue , Colesterol/metabolismo , Enterococcus faecium , Fermentação , Lactobacillus , Lipídeos/metabolismo , Triglicerídeos/sangue , Triglicerídeos/metabolismoRESUMO
Changes in microbial flora during the manufacture and maturation of Argentine Tafí cheese was examined. The microbial flora was found to be predominantly mesophilic streptococci, leuconostocs and homofermentative lactobacilli. Streptococcus lactis predominated on the surface and in the internal portion of the cheese after pressing. Streptococcus cremoris reached its maximum population after salting. The main microbial types during maturation were Lactobacillus casei and Lactobacillus plantarum . Pathogenic microorganisms were not detected in any of the samples analyzed.