Respiratory characteristics of two oligotrophic bacteria: Agromonas oligotrophica JCM 1494 and Aeromonas hydrophila 315.

Abstract

We have studied the respiratory characteristics in the growing and the resting cells in the soil oligotrophic bacterium Agromonas oligotrophica JCM 1494 and the aquatic oligotroph Aeromonas hydrophila 315. The growth of A. oligotrophica on 100 trypticase peptone plus 0.10 yeast extract medium (TY) was biphasic. The molar growth yield on oxygen consumed (Y02, g of cell dry weight/mol 02) in the first phase increased 1.7-fold in the second phase. In the growth of A. hydrophila, Yoz nearly doubled with shifting from TY to 10-fold diluted TY (TY/ 10). These two cases of significant Yoz increase may indicate the operation of an efficient energetic regulation of the respiratory system apparently in response to changing cell density and medium nutrient levels. The studies of in vitro respiration with resting cells on a single substrate (low organic acids) revealed rather higher Km values for A. oligotrophica and A. hydrophila than for Escherichia coli K12 as a reference strain. But the apparent Km of A. oligotrophica for TY as a complex respiratory substrate was definitely lower than that with E. coli K12. This suggests a unique simultaneous uptake for multiple substrates. In A. oligotrophica cells, a-, b-, and c-type cytochromes and a CO-binding b-type cytochrome (assumed to be cytochrome o) were identified. But the a type was not detected in A. hydrophila cells. These cytochrome patterns in the two strains, described in oligotrophs for the first time, were not detestably changed by medium dilution, and there appears to be a sequence leading to cytochrome o in the aerobic electron transfer in both strains.i Postdoctoral researcher , on leave

Oligotrophy and pelagic marine bacteria: facts and fiction

“…The copiotrophs Pseudomonas aeruginosa and Aeromonas hydrophila can grow in tap water supplied with microgram quantities of organic carbon 1-I (Van der Kooij et al 1980Kooij et al , 1982, and should according to definitions be considered oligotrophic (Ohta & Taniguchi 1988). All Enterobacteriaceae and most known pathogenic bacteria should be considered copiotrophic, yet 'oligotrophs' can be isolated from clinical samples (Tada et al 1995).…”

Energy metabolism of Actinobacillus actinomycetemcomitans during anaerobic and microaerobic growth in low- and high-potassium continuous culture

“…Fructose-dependent oxygen uptake activity of the microaerobically grown cells was slightly lower [1n26-1n36 mmol O # h −" (g dry wt) −" (mean of duplicate determinations)] than that of anaerobically grown cells [1n54 mmol O # h −" (g dry wt) −" ], indicating that no induction but a small suppression of respiratory capacity occurred in the microaerobic culture. It was also noted that the measured oxygen uptake rates were significantly low compared with those of washed cells of batch-grown & Taniguchi, 1988).…”