We have isolated four strains of Rhodococcus which specifically degrade estrogens by using enrichment culture of activated sludge from wastewater treatment plants. Strain Y 50158, identified as Rhodococcus zopfii, completely and rapidly degraded 100 mg of 17␤-estradiol, estrone, estriol, and ethinyl estradiol/liter, as demonstrated by thin-layer chromatography and gas chromatography-mass spectrometry analyses. Strains Y 50155, Y 50156, and Y 50157, identified as Rhodococcus equi, showed degradation activities comparable with that of Y 50158. Using the random amplified polymorphism DNA fingerprinting test, these three strains were confirmed to have been derived from different sources. R. zopfii Y 50158, which showed the highest activity among these four strains, revealed that the strain selectively degraded 17␤-estradiol during jar fermentation, even when glucose was used as a readily utilizable carbon source in the culture medium. Measurement of estrogenic activities with human breast cancer-derived MVLN cells showed that these four strains each degraded 100 mg of 17␤-estradiol/liter to 1/100 of the specific activity level after 24 h. It is thus suggested that these strains degrade 17␤-estradiol into substances without estrogenic activity.Natural estrogens, including 17␤-estradiol (E2), estrone (E1), and estriol (E3), are excreted in the urine of humans and cattle, most of which flows into wastewater treatment plants. As some natural estrogens are discharged into environments without processing, it is estimated that estrogen discharge is increasing in urban areas (14,15,17). Feminization of a male organism has been noted in rivers and lakes into which sewage is discharged from wastewater treatment plants, and loss of ecological balance is causing concern (7,20,21,29). Since the use of low-dosage oral contraceptive pills was approved by the Central Pharmaceutical Affairs Council in Japan in 1999, environmental loading of ethinyl estradiol (EE2), a synthetic estrogen, is expected to increase (27; T. Yoshimoto, S. Murakami, K. Hamasato, H. Omura, Y. Goda, A. Kobayashi, and S. Fujimoto, Abstr. 4th Annu. Meet. Jpn. Soc. Endocr. Disrupt. Res., p. 155, 2001).Between 1998 and 2000, the Ministry of Land, Infrastructure and Transport conducted a 3-year nationwide survey of 25 endocrine disruptors at 47 wastewater treatment plants in 13 districts of Japan (Tokyo, Sapporo, Sendai, Ibaraki, Saitama, Kawasaki, Yokohama, Nagoya, Shiga, Kyoto, Osaka, Kobe, and Fukuoka). E2, E1, and EE2 concentrations were measured in wastewater and treated wastewater flowing into wastewater treatment plants. EE2 was not detected in any sample in the treatment plants, but E1 and E2 were detected in all plants.The measurement values of E2 and E1 in wastewater influent and treated wastewater were 0.0091 to 0.094 g/liter (125 samples), Ͻ0.0002 (not detected) to 0.066 g/liter (146 samples), 0.015 to 0.077 g/liter (23 samples), and Ͻ0.0005 (not detected) to 0.063 g/liter (24 samples), respectively. The concentrations of E2 were analyzed by an enzyme...

SummaryWe studied the inhibitory effect of Cladosiphon fucoidan on the attachment of Helicobacter pylori (H. pylori), a gastroduodenal pathogen, to human gastric cell lines. The bacterial binding in these cell lines was inhibited more by Cladosiphon fucoidan (IC50=16-30mg/mL), than by the fucoidan from Fucus (IC50>30mg/mL). Dextran sulfate, another sulfated polysaccharide, did not inhibit the binding at all. Pre-incubating the bacterial suspension with fucoidans reinforced the inhibitory ability of these components, and reduced the IC50 value of Cladosiphon fucoidan to approximately 1mg/mL. However, the binding was not inhibited by pre-treatment of gastric cells with these com ponents. It was also shown that this fucoidan blocks both Leb and sulfatide-mediated attachment of H. pylori to gastric cells. Furthermore, fucoidan-binding proteins were found on the H. pylori cell surface by Western blot analysis. Thus, the inhibitory effect exerted by Cladosiphon fucoidan on binding between H. pylori and gastric cells might result from the coating with this component of the bacterial surface.

Lactate-utilizing butyrate-producers were isolated from human feces and identified based on the sequences of 16S rRNA gene. Anaerostipes caccae strain L2, one of the seven human fecal isolates, was administered to rats with galacto-oligosaccharides (GOS) as bifidogenic carbohydrates for stimulating lactate formation in the hindgut. Ingestion of GOS alone increased concentrations of cecal lactate and butyrate compared with control rats (P<0.05). Additional administration of strain L2 on GOS tended to enhance the promoting effect of GOS on cecal butyrate formation (P=0.06) and lowered the mean value of cecal lactate concentration (P=0.32). Consequently, cecal and fecal butyrate concentrations in rats administered with both strain L2 and GOS were significantly higher than those in the control rats (P<0.01 and P<0.05, respectively). Significant changes were observed in the other fermentation acids, such as succinate, acetate, and propionate, depending on the ingestion of strain L2. Administered strain L2 was retrieved from the cecal content of a rat based on randomly amplified polymorphic DNA analysis. The results suggest that synbiotic ingestion of lactate-utilizing butyrate-producers and GOS alters the microbial fermentation and promotes the formation of beneficial fermentation acids, including butyrate, in the gut.

The antioxidative effects of lactic acid bacteria on lipid peroxidation in the colonic mucosa were investigated. Among 49 strains of lactic acid bacteria, Streptococcus thermophilus YIT 2001 showed the highest inhibitory activity against lipid peroxidation in liposomes induced by ferrous iron. Feeding a diet containing 0.4% St. thermophilus YIT 2001 (2 x 10(8) colony-forming units per mouse per day) for 2 weeks caused a significant decrease of lipid peroxide (thiobarbituric acid reactive substance) in the colonic mucosa of iron-overloaded mice (0.07% Fe in the diet). The mucosal lipid peroxide level did not correlate with the soluble iron concentration of the cecal contents. Therefore, it is suggested that the antioxidative effect of St. thermophilus YIT 2001 in the colonic mucosa was not due to the removal of ferrous iron from the reaction system of lipid peroxidation.

The cellular components involved in the hypocholesterolemic activity of Kluyveromyces marxianus YIT 8292 were examined in rats fed on a high-cholesterol diet. Whole cells (KM) were heated at 115 degrees C for 10 minutes and fractionated into water-soluble extract 1 and the insoluble residue (KM-CW). After mechanical disruption by glass beads, KM-CW was separated into the cell wall (KM-W) and water-soluble extract 2. Plasma total cholesterol was decreased by feeding KM-CW or KM-W, but was not changed by feeding extract 1 or extract 2. Feeding KM-CW and KM-W increased the fecal sterol excretion and concentration of short-chain fatty acids (SCFA) in the cecum. The hypocholesterolemic activity of KM-CW was completely abolished by the enzymatic degradation of alpha-mannan and beta-glucan. These results suggest that alpha-mannan and beta-glucan were the major active components of KM, and that its hypocholesterolemic activity may be attributable to the increasing fecal sterol excretion and/or production of SCFA.