Akiyoshi Hosono

Antidiabetic effect of Lactobacillus GG in streptozotocin-induced diabetic rats

Neonatally streptozotocin-induced diabetic (n-STZ) rats were given food containing Lactobacillus GG cells (GG) or a control diet (control), from 9 to 18 weeks of age. The GG cells significantly lowered the blood hemoglobin A1C (HbA1C) level and improved glucose tolerance in n-STZ rats (p<0.05). In the GG group, the serum insulin level at 30 min after glucose loading was significantly higher than in the control group (p<0.05).

Selection of acid tolerant Bifidobacteria and evidence for a low-pH-inducible acid tolerance response in Bifidobacterium longum

Acidity is an environmental condition commonly encountered by lactic acid bacteria and bifidobacteria in the gastrointestinal tract and fermented foods. In the present study, 22 strains of Bifidobacterium were screened for acid tolerance in artificial gastric juice (AGJ, pH 3.0) and fermented milk. AGJ tolerance was found to be strain-specific, with a pronounced variation among the strains. Several strains with a high survival rate in AGJ that belonged to Bifid. longum, Bifid. breve and Bifid. adolescentis were selected. Among them, only strain BL1 of Bifid longum was found to possess a high survival rate in fermented milk during refrigerated storage. Strain BL1 exhibited a survival rate of more than 25% in AGJ at pH 3.0 for 2 h and maintained a viable cfu level of more than 10(8) per gram of product in fermented milk (pH 4.6) under refrigerated conditions for 2 weeks. The acid tolerance of strain BL1 was found to depend on the final growth pH (<4.5). Rapid loss of acid tolerance was observed when the cells were shifted from acid to neutral conditions by addition of NaOH. Strain BL1 cells were able to maintain much higher intracellular pH under acid conditions, in comparison with those of AGJ sensitive mutant (BL1-S) or cells that lost acid tolerance following pH shifting from acid to neutral conditions. These results suggested that a cytoplasmic pH homeostasis system may function in the acid tolerance response in this strain.

Hypocholesterolemic effect of Lactobacillus gasseri SBT0270 in rats fed a cholesterol-enriched diet

The effects of administration of Lactobacillus gasseri SBT0270 on serum lipids and bile acids, faecal bile acids and microflora were estimated in hypercholesterolemic rats. An effective dose of strain SBT0270 to exert its hypocholesterolemic effect was 10(9) viable cells/d. The dose of 10(9) cells/d did not affect the faecal coliform counts, but the number of faecal lactobacilli in rats fed this dose was significantly higher than that in the control group observed at the end of feeding period. Hypocholesterolemic effect of Lb. gasseri SBT0270 was attributed to its ability to suppress the reabsorption of bile acids into the enterohepatic circulation and to enhance the excretion of acidic steroids in faeces of hypercholesterolemic rats.

Studies on antimutagenic effect of milk cultured with lactic acid bacteria on the Trp-P2-induced mutagenicity to TA98 strain of Salmonella typhimurium

The inhibitory effects of cultured milk using 76 strains of lactic acid bacteria isolated from milk products were investigated on the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P2), a tryptophan pyrolysate for Salmonella typhimurium TA98. Each cultured milk sample displayed its characteristic antimutagenic effect against the mutagenicity of Trp-P2. The milk cultured with Lactobacillus acidophilus LA106 (LA2) showed the highest inhibition of 82.1% among the strains used. Milk samples cultured with Lactococcus lactis subsp. lactis, Lll103 (10-3) and Lll102 (KM) also exhibited higher inhibition percentages.

Antimutagenic activity of whole casein on the pepper-induced mutagenicity to streptomycin-dependent strain SD 510 of Salmonella typhimurium TA 98

When the antimutagenic activity of milk or cultured milk components on the pepper-induced mutagenicity to streptomycin-dependent strain SD 510 of Salmonella typhimurium TA 98 was investigated, whole casein showed a significant antimutagenic activity. Heating at 121 °C for 15 min completely destroyed the antimutagenic activity of casein, which was temperature dependent. While acid or papain digestion resulted in the loss of antimutagenic activity of casein, trypsin digestion had little effect although the digestion of casein by each proteinase was over 75%. β-Casein, egg albumin, and bovine serum albumin also had a similar antimutagenic activity to that of whole casein.

Biochemical characteristics of Enterobacter agglomerans and related strains found in buckwheat seeds

Thirty strains of bacteria were randomly isolated and identified from buckwheat seeds. The phenotypic characteristics of these strains agree well with those of the Enterobacter agglomerans-Erwinia herbicola complex. On the basis of the difference in indole production and gas production from D-glucose, the isolates were divided into 3 phenotypic groups, viz. I, II and III. Twenty two strains were in phenotypic group 1, which is negative for indole production and gas production from D-glucose, and resembles Pantoea agglomerans. All six strains in phenotypic group II, which is positive for indole production and negative for gas production from D-glucose, were identified as Erwinia ananas. Two strains in phenotypic group III, which is negative for indole production and positive for gas production from D-glucose, were identified as Rahnella aquatilis.

Ammonia production from amino acids and urea in the caecal contents of the chicken.

1. Ammonia production from urea and amino acids in the caecal contents of the chicken was evaluated using 15N-labeled nitrogenous compounds. 2. About 43% of each of urea nitrogen and glutamine amide nitrogen was converted to ammonia nitrogen, but only 25% of epsilon-nitrogen of the added arginine, a precursor of urea, was found in ammonia. 3. Amino nitrogen of the separately added glutamic acid and glycine to be converted to ammonia was 19-20% of their added amounts, whereas that of alpha-alanine was 11%. 4. It is concluded that dietary and urinary amino acids and urea which find their ways into the caeca are useful nitrogen sources for ammonia production by microflora in the caeca of the chicken.

Antigenic Reactive Regions of S-Carboxymethylated β-Lactoglobulin

Rabbit antibody to reduced carboxymethylated bovine β-lactoglobulin (SCM-β-Lg) was prepared and characterized in order to study the antigenic property of bovine β-lactoglobulin (β-Lg) which is a potential cause of an allergy to cow’s milk.On immunodiffusion analysis, a clear, single precipitin arc was produced between SCM-β-Lg and its antiserum, while a barely discernible line was observed between β-Lg and anti SCM-β-Lg antiserum. Analysis of the quantitative precipitation of SCM-β-Lg with β-Lg-absorbed antiserum to SCM-β-Lg indicated that there were at least four antigenic sites on SCM-β-Lg.In a quantitative precipitin inhibition test and a two-step inhibition test involving an enzyme- linked immunosorbent assay, anti SCM-β-Lg antibody reacted with peptides 1 ~ 65, 25 ~ 61, 25 ~ 107, 41 ~ 107, 62 ~ 107, 108 ~ 145, 125 ~ 145 and 146 ~ 162 from β-Lg, whereas peptides located in the TV-terminal region, i.e., 1 ~ 7, 8 ~ 24 and 25 ~ 40, and peptide 108 ~ 124 showed little or no measurable affinity for antibod...

Bacterial mutagenicity of terasi and antimutagenicity of Indonesian jasmine tea against terasi

Terasi, a traditional fermented product of Indonesia was evaluated by Salmonella mutagenesis assay. The higher the heating temperature and the longer the heating time, the more mutagenicity observed in both terasi and its starter, and the highest mutagenic activity was shown by heating each of them at 100 degrees C for 60 min. Terasi starter has stronger mutagenic properties as compared to terasi. Indonesian jasmine tea, which is a yellow tea, was examined for its antimutagenic properties against mutagenic terasi. Tea component presented in fraction C (water soluble, chloroform and ethyl acetate insoluble fraction) as well as in fraction D (water soluble, chloroform, ethyl acetate and n-butanol insoluble fraction) were found to suppress the mutagenicities exerted by heated terasi and heated terasi starter. Yet, the tea components presented in fraction E (chloroform soluble fraction) were found to enhance the mutagenicity of terasi.

Antimutagenic activity of Camembert cheese on the Trp-P-1-induced mutagenicity to streptomycin-dependent strain SD510 of Salmonella typhimurium TA98

Antimutagenic activity of Camembert cheese during ripening against the mutagenicity of an amino acid pyrolysate, Trp-P-1, using the streptomycin-dependent strain (SD510) of Salmonella typhimurium TA98, was studied. The starter used for the manufacture of Camembert cheese consisted of four strains of lactic acid bacteria and one strain of Penicillium candidum. The antimutagenicity of Camembert cheese was very high and increased during ripening. When 1% cheese suspension was used, the antimutagenicity was 19% at zero week, 36% at 1 week, 50% at 2 weeks, 60% at 3 weeks and 64% at 4 weeks. It was difficult to correlate between the ripening time and antimutagenicity at a higher concentration. At a lower concentration, the activity was too low to study.