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Biomedical subjects

N B Gerhardt

Publications and source records attributed to N B Gerhardt.

4 recordsLinked to original sources
PubMed1978

Identification of an antibiotic-producing bacterium from the human intestinal tract and characterization of its antimicrobial product.

An antibiotic-producing bacterium repeatedly isolated from human feces was characterized by standard bacteriological methods. The bacterium is a gram-positive bacillus possessing morphological and physiological features similar to those of Bacillus subtilis, except that it lacks temperature-resistant spore formation and has peritrichous flagella. The cell-free antibiotic produced by the organism in vitro was effective against some gram-negative and gram-positive bacteria and yeast in minimum inhibitory concentration and antibiotic disk assays. The 1,200-dalton antibiotic had an optimal activity against Proteus vulgaris within the pH range of 5.7 to 6.8. The activity was totally destroyed by digestion with pronase and trypsin but was resistant to pepsin, chymotrypsin, papain, and nuclease digestion. In addition, the antibiotic activity against P. vulgaris was stable between pH 3 to 9 and within the temperature range of 20 to 100 degrees C when tested in the fermentation medium. The activity was only partially retained by membrane filters which normally retain globular proteins of molecular weights between 500 to 10,000. Electrophoresis in phosphate buffer indicated that the activity against P. vulgaris had an isoelectric point of approximately 6.45. These properties are compatible with the antibiotic activity associated with a small peptide.

Anti-Bacterial Agents↗
PubMed1976

Alterations in the fecal flora of an individual frequently lacking coliforms.

An individual who usually completely lacked or had very low numbers of coliforms in his stool over a period of 19 months was identified. The subject's levels of clostridia and aerobic lactobacilli were elevated as compared with those of our control group. However, these elevated populations of microorganisms were not related to the number of coliforms present in stool samples. The number of coliforms was inversely related to the number of anaerobic lactobacilli. In addition, the absence of coliforms was always accompanied by the absence of fungi. Populations of other prominent groups of intestinal flora were not significantly affected by the number of coliforms present in the intestnal tract. Since ankylosing spondylitis was the only physical abnormality of the subject, the intestinal flora of other individuals positive for histocompatibility antigen B27 who had this disease were examined but were found to be normal. The absence of coliforms from the normal flora of the intestinal tract of the subject had no apparent effect on his general health.

Adult↗
PubMed1975

Ascorbate and phagocyte function.

Scorbutic guinea pig neutrophils (PMN) were found to produce H2O2 and kill Staphylococcus aureus as well as control PMN, suggesting that ascorbate does not contribute significantly to phagocyte H2O2 production or bacterial killing. Total and reduced ascorbate contents of human PMN was observed to fall upon phagocytosis, whereas dehydroascorbate increased to a lesser extent. These observations are consistent with the view that ascorbate constitutes a functional part of the PMN's redox-active components and may thus function to protect cell constituents from denaturation by the oxidants produced during phagocytosis.

2,3-Diketogulonic Acid↗