Biomedical subjects

R K Porschen

Publications and source records attributed to R K Porschen.

21 records · Page 2Linked to original sources

PubMed1974

Phosphatase activity of anaerobic organisms.

Anaerobic organisms were tested for phosphatase activity in different pH ranges. Several groups of organisms displayed characteristic patterns. Bacteroides fragilis, B. melaninogenicus, and B. ruminicola produced phosphatase with strongest activity at pH 8.6. Fusobacterium mortiferum was the only species of this genus to show strong hydrolysis. The enzyme was active in both acid and alkaline ranges. The activity of gram-positive organisms was variable, the most active groups being Clostridium perfringens, Peptostreptococcus intermedius, P. micros, and Peptococcus constellatus. The incorporation of phosphatase activity into the identification scheme of anaerobes seems feasible. There was a correlation of hydrolysis with several important pathogens.

Anaerobiosis↗

PubMed1974

Extracellular deoxyribonuclease production by anaerobic bacteria.

The production of extracellular deoxyribonuclease was examined with anaerobic organisms isolated from clinical specimens. Nuclease activity was extraordinarily common. All strains of Fusobacterium, including eight species, as well as Bacteroides fragilis and B. melaninogenicus, displayed enzyme activity. Whereas the gram-positive bacteria were generally less productive, all strains of Clostridium perfringens, Peptostreptococcus intermedius, and P. anaerobius specifically produced deoxyribonuclease. The test is taxonomically valuable, particularly in the characterization of gram-positive cocci, since a deoxyribonuclease-producing coccus indicates P. intermedius or P. anaerobius. Additionally, possession of the enzyme may prove to be a useful correlate of the potential pathogenicity of anaerobes.

Anaerobiosis↗

PubMed1974

Fluorescent antibody study of the gram-positive anaerobic cocci.

Fluorescent antibody conjugates were prepared from five species of anaerobic cocci commonly isolated from human infections. When tested with homologous and heterologous cells these conjugates were found to be highly specific. There was no evidence of a common genus antigen. Peptococcus magnus conjugates detected a species-specific antigen; cross-reactions with Peptostreptococcus anaerobius were readily eliminated by absorption. The conjugates from Peptococcus asaccharolyticus, Peptococcus prevotii, Peptostreptococcus, anaerobius, and Peptostreptococcus intermedius displayed a high degree of strain specificity. Occasional cross-reactions were detected with homologous strains, suggesting the presence of common antigens, but no attempt was made to determine the number of different serotypes in these species.

Anaerobiosis↗