Reduction of population levels of some indigenous bacteria by lactobacilli in the gastrointestinal tract of gnotobiotic rats

Effects of each of three indigenous Lactobacillus groups on other bacterial populations were separately investigated in gnotobiotic rats. In the wall of the non-glandular part of the stomach, contents of the stomach and contents of the upper part of the small intestine, some pre-associated indigenous bacteria were reduced to conventional population levels by introducing three groups of lactobacilli: Group I (Lactobacillus acidophilus and related strains), Group II (L. fermentum) and the groups mixed. However, no obvious reduction in cell numbers of the pre-associated bacteria occurred in the case of Group III (L. murini).

Effect of Tween 80 on glucosyltransferase production in Streptococcus mutans

Glucan production from sucrose by Streptococcus mutans OMZ 176 was stimulated approximately threefold in the presence of 0.1% Tween 80. When OMZ 176 was grown in a medium containing glucose, the glucosyltransferase level in the medium was also increased about fivefold in the presence of 0.1% Tween 80. The glucosyltransferase level increased in proportion to the logarithm of the concentration of Tween 80 in the glucose medium. Tween 80 affected neither bacterial growth nor the activity of glucosyltransferase. The appearance of glucosyltransferase in the glucose medium was inhibited immediately by chloramphenicol and actinomycin D and, after a lag, by rifampin as well. It was observed that the fatty acid composition of the cells grown with Tween 80 was altered. These results suggest that Tween 80 stimulates glucosyltransferase synthesis either directly, or indirectly by promoting glucosyltransferase secretion.

Distribution of indigenous Lactobacilli in the digestive tract of conventional and gnotobiotic rats

Distribution of indigenous lactobacilli in the gastrointestinal tracts of rats was investigated at the species level. The indigenous lactobacilli isolated from conventional rats were divided into three groups, Lactobacillus acidophilus and its related strains, L. fermentum, and L. murini. Localization of the Lactobacillus groups in the gastrointestinal tracts could be distinguished clearly based on arabinose and glucose fermentation reaction of isolates from each part of the gastrointestinal tract. Group I (L. acidophilus and the related strains) and Group II (L. fermentum) were the major populations of lactobacilli on the walls of the non-glandular part and in the contents of the stomachs of both conventional and gnotobiotic rats. Group I predominated in all the parts of the digestive tract of conventional rats, whereas Group II was in the minority in the lower part of the gastrointestinal tracts of both groups of rats. Group III (L. murini) was the predominant population of Lactobacillus in the lower part of small intestine of conventional rats and in all parts of the gastrointestinal tracts of gnotobiotic rats except for the wall of the non-glandular part of the stomach.

Intestinal microflora in rats: isolation and characterization of strictly anaerobic bacteria requiring long-chain fatty acids

Three strains of strictly anaerobic bacteria, isolated from the cecal contents of rats, have strict requirements for long-chain fatty acids. The effect of exogenous fatty acids on the growth and fatty acid composition of the bacteria was examined. Biohydrogenation of linoleic acid into octadecenoic acid was observed. These observations suggest that long-chain fatty acids in the intestine are factors in controlling the localization and the population levels of indigenous bacteria in vivo in rats.

Pituitary-thyroid function in trophoblastic disease

Pituitary-thyroid function was assessed in 12 patients with trophoblastic disease (4 hydatidiform mole, 3 invasive mole, and 5 choriocarcinoma). Thyroid-stimulating activity was detectable, by means of the McKenzie bioassay, in 6 patients (Group 1) but not in the other 6 patients (Group 2). In Group 1 serum thyrotropin (TSH) determined by radioimmunoassay was mostly undetectable and did not respond to the administration of thyrotropin-releasing hormone (TRH) determined by radioimmunoassay was mostly undetectable and did not respond to the administration of thyrotropin-releasing hormone (TRH), while in Group 2 basal TSH was detectable in half of the patients and responded to TRH in all cases. Serum concentrations of total thyroxine (T4) (18.7 +/- 2.0 mug/100 ml, mean +/- SE), free T4 (4.9 +/- 0.04 ng/100 ml), total triiodothyronine (T3) (352 +/- 72 ng/100 ml), and free T3 (0.57 +/- 0.11 ng/100 ml) in Group 1 were statistically greater than those in Group 2 (total T4, 9.2 +/- 1.0 mug/100 ml, free T4, 2.0 +/- 0.2 ng/100 ml; total T3 156 +/- 20 ng/100 ml, and free T3 0.23 +/- 0.03 ng/100 ml). Free T4 and T3 fractions were within normal limits in both groups. After treatment of 5 patients in Group 1, the thyroid stimulating activity determined by bioassay dropped to undetectable levels, the serum concentrations of thyroid hormones decreased to normal limits, and TSH response to TRH became positive. These findings indicate that an abnormal thyroid stimulator, derived from the trophoblastic tissue, stimulated the thyroid hormone secretion from the thyroid gland and in turn suppressed TSH response to TRH in some patients with trophoblastic disease.

In vitro N-nitrosodimethylamine formation by some bacteria

It was found that human pathogenic bacteria and some species of intestinal bacteria in rats have the ability to catalyze the formation of N-nitrosodimethylamine from dimethylamine and nitrate in vitro.

Distribution of indigenous bacteria in the digestive tract of conventional and gnotobiotic rats

The localization and population levels of the indigenous bacterial flora of conventional rats were investigated by cultural and histological techniques. Lactobacilli predominate in the stomach and upper part of the small intestine and associate with keratinized cells of the nonglandular portion of stomach. Mixtures of varying complexity of pure cultures of indigenous bacteria were inoculated into germfree rats. The distribution of these bacteria was examined to investigate the effect of lactobacilli in controlling the composition of other bacterial species in each portion of the digestive tract. In the stomach and the upper part of the small intestine, lactobacilli controlled the population levels of other bacterial species. In the lower part of the small intestine, not only lactobacilli but also the anaerobes which colonized the large bowel influenced the population levels of other bacterial types. Staphylococci isolated from a conventional rat colonized specifically the keratinized cells of the nonsecreting epithelium of the stomach when the rats were free from lactobacilli. This colonization was not observed after inoculation of lactobacilli into the rats.

Glycopeptides from the egg jelly coat of the toad Bufo vulgaris

1. Glycopeptides isolated by exhaustive pronase digestion from the egg jelly coat of toad, Bufo vulgaris, were separated by DEAE-cellulose chromatography into two fractions. These fractions each gave a single band when they were subjected to electrophoresis on cellulose acetate strips. The glycopeptides behaved as a kind of "macroglycopeptide" on gel chromatography. 2. The glycopeptide fractions contained as sugar components galactosamine, glucosamine, galactose, fucose and N-acetylneuraminic acid. The amino acid composition was characterized by the presence of threonine and serine, which accounted for approximately 70% of the total amino acids. 3. Large amounts of galactosamine, threonine and serine were destroyed by treatment with alkali, indicating that the carbohydrate-peptide linkage in the glycopeptides is mostly an O-glycosidic bond between N-acetylgalactosamine and the hydroxy groups of threonine and serine.

Reassociation kinetics for Epstein-Barr virus DNA: nonhomology to mammalian DNA and homology of viral DNA in various diseases

The number of Epstein-Barr virus (EBV) genomes per cell in established leukocytic lines and tissue specimens has been evaluated by measuring DNA-DNA reassociation kinetics with hydroxyapatite chromatography. Under the proper conditions, this method is sufficiently sensitive to detect EBV DNA in the amount of 0.1 genome per cell. All the samples tested that have been suspected to be without EBV DNA by cRNA hybridization proved negative by this more sensitive specific analysis. These included Hela and Hep2 cells, a negative case of Burkitt's lymphoma, two negative cases of nasopharyngeal carcinoma, and two established human leukocytic lines. Homology tests conducted with single-strand-specific nuclease S1 indicated that the viral DNA from a nasopharyngeal carcinoma and infectious mononucleosis were more than 90% homologous to EBV DNA.