ジアエンソサンナトリウムエキ ノ ユウコウ リヨウ ニ カンスル ケントウ

Sodium hypochlorite solution is cheap and powerful disinfectant widely used in hospitals and food industries. The bactericidal activity of chlorine solution is considered to depend on the amount of dissociated hypochlorite (HClO) in the solutions. The most important factor affecting the amount of HClO in the chroline solution is pH, and the decrease in pH increases the concentration of dissociated HClO. Alkaline solutions of both sodium and calcium hypochlorite contain only small amount (about 10% of free available chroline in these solution) of HClO. Recently, there are several reports showing the effectiveness of “acidic hypochlorite solution”, which is adjusted pH with hydrochloric acid (HCl) to 5.0, as a powerful disinfectant. However, special attention must be paid to handling and storage of HCl, and the increase of chlorine content in the solution by the addition of HCl might possibly induce toxic chlorine gas production. In this study, the bactericidal activity of acidic hypochlorite solutions, which have been adjusted to pH 5.0 with hydrochloric acid, acetic acid, citrate, lactate, formate, phosphate or sulphate, was investigated using various bacterial strains. The acidic hypochlorite solution prepared with acetic acid showed the equivalent bactericidal activity to that with hydrochloric acid and killed all of the Bacillus subtilis spores within 10 min. In addition, the acidic hypochlorite solution with acetic acid killed all of bacterial cells of Escherichia coli O157 : H 7, Legionella pneumophila, Pseudomonas aeruginosa, Salmonella Typhimurium and methicillin-resistant Staphylococcus aureus within 30 sec. On the other hand, the solutions prepared with citrate and lactate showed no bactericidal activity against any bacterial strains tested in this study despite of low pH. We proposed that acetic acid is a desirable acid to safely and easily prepare the acidic hypochlorite solution with the equivalent bactericidal activity to the solution prepared by HCl

Activation of 1-nitropyrene by nitroreductase increases the DNA adduct level and mutagenicity

1-Nitropyrene (1-NP) is a mutagenic nitro compound in the environment. We studied correlations between the mutagenicity of 1-NP for three strains of Salmonella typhimurium, the activity of bacterial nitroreductases and the amount of 1-NP-derived DNA adducts. Bacterial strains used in this study were S. typhimurium strains TA98, nitroreductase-less mutant TA98NR and YG1021 carrying a nitroreductase-producing plasmid. The mutagenicity of 1-NP was measured using the Ames assay, and the nitroreductase activities of these strains were assayed by quantification of 1-aminopyrene produced from 1-NP. The DNA adducts were measured by the 32P-postlabeling method. Among the three bacterial strains, strain YG1021 was the highest in mutagenicity of 1-NP, the nitroreductase activity and the DNA adduct level. However, S. typhimurium strain TA98NR had the lowest values of these three parameters. Nitroreductase activity, DNA adduct level and mutagenicity were strongly correlated with each other. These results indicate that bacterial nitroreductase plays an important role in forming the DNA adducts, and that the higher the adduct level the higher the level of mutagenicity

Role of unbalanced growth of Gram-negative bacteria in ileal ulcer formation in rats treated with a nonsteroidal antiinflammatory drug

Nonsteroidal anti-inflammatory drugs (NSAIDs) induced formation of intestinal ulcers as side effects, in which an unbalanced increase in the number of Gram-negative bacteria in the small intestine plays an important role. To clarify how intestinal microflora are influenced by NSAIDs, we examined the effects of 5-bromo-2-(4-fluorophenyl)-3-(4-methylsulfonylphenyl) thiophene (BFMeT), an NSAID, on intestinal motility and on the growth of Escherichia coli and Lactobacillus acidophilus. Transit index, a marker of peristalsis, was not different in BFMeT-treated and solvent-treated rats, indicating that BFMeT increased the number of Gram-negative bacteria without suppression of peristalsis. The factors that affect the growth of intestinal bacteria were not found in intestinal contents of BFMeT-treated rats, because the growth of E. coli and that of L. acidophilus in the supernatants of small intestinal contents of BFMeT-treated rats and solvent-treated rats were not different. The mechanism of the increase in the number of Gram-negative bacteria is still unclear, but heat-killed E. coli cells and their purified lipopolysaccharide (LPS) caused deterioration of BFMeT-induced ileal ulcers, while they could not cause the ulcers by themselves without the NSAID. Concentration of LPS and myeloperoxidase activity level were elevated correlatively in the intestinal mucosa of rats treated with LPS and BFMeT. These results suggest that an increase in the number of Gramnegative bacteria and their LPS in the mucosa induces activation of neutrophils together with the help of NSAID action and causes ulcer formation

PCR-dot blot hybridization based on the neuraminidase-encoding gene is useful for detection of Bacteroides fragilis

Bacteroides fragilis is a Gram-negative obligate anaerobe frequently isolated from clinical specimens and sometimes causes severe septicemia in compromised hosts. Increasing interest has been shown in the enterotoxigenicity and drug resistance of B. fragilis in the field of medical microbiology. We previously reported rapid detection of this anaerobe by nested PCR targeting a neuraminidase-encoding gene nanH. In the present study, we synthesized a digoxigenin-labeled oligonucleotide probe, NH1,which is specific for nanH of B. fragilis, and we combined the hybridization assay using NH1with the nanH-PCR to detect this anaerobe in a bacteremia model mice. In the specificity test, the oligonucleotide probe, NH1, hybridized only to amplification products from B. fragilis. PCR-dot blot hybridization based on nanH enabled detection of cells of B. fragilis in blood samples even when the number was as low as 2x103colony-forming units/ml. These findings suggest that PCR-dot blot hybridization targeting nanH is a useful procedure for diagnosis of septicemia caused by B. fragilis when viable cells in blood cannot be detected by the traditional culture techniques

Effects of indole-3-carbinol and phenethyl isothiocyanate on bile and pancreatic juice excretion in rats

Bile and pancreatic juice contain a number of parameters for cancer chemoprevention. Indole-3-carbinol (I3C) and phenethyl isothiocyanate (PEITC), which are hydrolytic products of brassica plants, have been established to be anti-cancer agents. Here, we developed a method for the continuous and selective sampling of bile and pancreatic juice, and the effects of I3C and PEITC on bile and pancreatic excretion and γ-glutamyl transpeptidase (γ-GTP) activity in the samples were investigated. Male Fisher 344 rats (eight weeks of age) were challenged intragastrically with I3C (150 mg/kg) or PEITC (160 mg/kg) for five days. Twenty-four hours after the final administration, cannulation was undertaken into the rats’ bile and pancreatic ducts, and the bile and pancreatic juice were separately collected for 48 h. In this rat model, bile was stably excreted, and the bile and pancreatic excretion of the control rats was 21.9±1.4 ml/48 h and 12.8±1.7 ml/48 h, respectively. Bile excretion for the first 24 h significantly increased in the I3C- or PEITC-treated rats compared with the control rats. In the case of pancreatic juice, excretion during the first 24 h significantly increased in the PEITC-treated rats. In bile, γ-GTP activity was significantly increased for the first 24 h in the I3C- and PEITC-treated rats, but no difference was observed in the pancreatic juice. Increases of bile excretion and γ-GTP activity in bile might be a factor involved in the anti-cancer effect of I3C and PEITC. Our rat model described here is a useful tool for the study of cancer chemoprevention

Characterization of a gene cluster for sialoglycoconjugate utilization in Bacteroides fragilis

Recent analysis of the whole genome sequence of Bacteroides fragilis revealed extensive duplication of polysaccharide utilization genes in this anaerobe. Here we analyzed a unique 27-kb gene cluster (sgu) comprised of the 13 sialoglycoconjugates-utilization genes, which include the sialidase gene (nanH1) in B. fragilis strain YCH46. The genes were tightly organized and transcribed polycistronically. Comparative PCR scanning demonstrated that the sgu locus was conserved among the Bacteroides strains tested. Based on the transcriptional profiles generated by reverse transcriptase PCR, the sgu locus can be classified into at least three regulatory units : 1) sialic acid- or sialooligosaccharide-inducible genes, 2) constitutively expressed genes that can be down-regulated by catabolite repression, and 3) constitutively expressed genes. In vitro comparison of the growth of a sgu locus deletion mutant (SGUM172941) with a wild type strain indicates that this locus is necessary for B. fragilis to efficiently utilize mucin as a carbon source. Furthermore, SGUM172941 was defective in colonization of the intestines of germfree mice under competitive conditions. These data indicate that the sgu locus in B. fragilis plays a crucial role in the utilization of host-derived sialoglycoconjugates and the stable colonization of this anaerobe in the human gut

Effects of fermented brown rice on the intestinal environments in healthy adult

Purpose : The aim of this study is to investigate the prebiotic effects of brown rice fermented by Aspergillus oryzae (FBRA) on the intestinal environment in vitro and in healthy adults. Methods : Fresh fecal slurries from six healthy adults were incubated with FBRA to confirm prebiotic potentials of FBRA. Another thirty-six healthy adults were randomly allocated to 2 groups for the clinical study. Subjects consumed 21.0 g/day of either FBRA or control food for 2 weeks, followed by a 12-week intermission and then 2-week ingestion vice versa. Main outcome measures were bifidobacterial numbers and organic acid concentration in feces. Sub outcome measures were fecal microbiota, fecal environments and bowel function. Results : Incubation of fecal slurries with FBRA in vitro resulted in increased organic acids with individual-specific patterns. Bifidobacterial numbers were increased during incubation. In the clinical study, all participants safely completed this study. FBRA had little effect on fecal number of bifidobacteria, concentrations of organic acids or putrefactive metabolites, fecal pH, or fecal microbiota. Conclusion : FBRA has the potentials as a prebiotic, however, we could not detect its effects on the intestinal environment in vivo. The results in a clinical study indicated that FBRA could be safely used for healthy adults

Inhibitory effects of asiatic acid and CPT-11 on growth of HT-29 cells

Asiatic acid is a pentacyclic triterpene contained inmedicinal plants. The cytotoxic effect of this compound and its augmentative effect on the anticancer drug irinotecan hydrochloride (CPT-11) were investigated in the human colon adenocarcinoma cell lineHT-29. Asiatic acid dose-dependently showed cytotoxicity in HT-29 cells. DNA fragmentation, annexin-positive apoptotic cells, andcaspase-3 activation were observed in a dose-dependent manner. Acaspase-3 inhibitor suppressed the DNA ladder formation in a concentration-dependent manner. Bcl-2 and Bcl-xL proteins were decreased by asiatic acid treatment. These results indicate that asiatic acid induced apoptosis inHT-29 cells viacaspase-3activation.Cytotoxic effectsof combined treatment with CPT-11 and asiatic acid on HT-29 cells were further examined. Simultaneous treatment or sequential exposure first to asiatic acid and then to CPT-11 showed an additive effect. Synergism was observed when cells were first exposed to CPT-11 and then to asiatic acid. These results suggest that asiatic acid can be used as an agent for increasing sensitivity of colon cancer cells to treatment with CPT-11 or as an agent for reducing adverse effects of CPT-11

Antimutagenicity of Murdannia loriformis in the Salmonella mutation assay and its inhibitory effects on azoxymethaneinduced DNA methylation and aberrant crypt focus formation in male F344 rats

An 80% ethanol extract of Murdannia loriformis, a Thai medicinal plant, was examined for antimutagenic activity and cancer chemopreventive activity. In the Salmonella mutation assay, the extract showed antimutagenicity against 2-amino-3-methylimidazo [4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,4-dimethyl- 5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldipyrido [1,2-a:3’,2’-d] imidazole, 2-aminodipyrido[1,2-a:3’,2’-d]imidazole, 2-aminoanthracene, 2-(2- furyl)-3-(5-nitro-2-furyl) acrylamide,N-methyl-N’-nitro-N-nitrosoguanidineandmethylazoxymethanol acetate and reduced their mutagenicities to 31.4～67.9% at the dose of 10mg/plate. However, it did not inhibit the mutagenicities of 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3-methyl-9 H-pyrido[2,3-b]indole, benzo[a]pyrene,N-ethyl-N’-nitro-N-nitrosoguanidine and 1-nitropyrene. The extract itself showed no mutagenicity. The chemopreventive activity of M. loriformis was examined using azoxymethane (AOM)-induced aberrant crypt focus (ACF) formation in the colon of F344 rats. The extract at doses of 0.1-1.0 g/kg wt significantly inhibited ACF formation in the initiation stage (21-51%), although it wasmore effective at a lower dose. In the post-initiation stage, the extract also tended to inhibit ACF formation (12 -27%) and significantly decreased the number of larger ACFs that have more than 3 aberrant crypts per focus. The extract inhibited the formation of O6-methylguanine and N7-methylguanine in the colonic mucosa and muscular layers but not or increased in the liver. These results indicate that M. loriformis extract has antimutagenic activity toward variousknownmutagens and that it inhibits AOM-induced ACF formation both in the initiation and post-initiation stages in the rat colon