Starvation of marine flounder, squid and laboratory mice and its effect on the intestinal microbiota

Abstract Starvation processes of microorganisms in natural ecosystems were studied, both in vivo and in vitro, using marine animals (flounder and squid) and laboratory mice. In flounder, starvation resulted in the mixed intestinal microbiota maintaining its viability but decreasing its cell volume. It was also observed that during starvation there was an increased liability for adhesion of th microbiota to both the oil-water interface in the hexadecane water separation technique, and to Sepharose beads with either exposed hydrophobic or cationic charge groups. The population also exhibited the capacity to respond immediately to the addition of nutrients. When the flounder microbiota was starved in vitro the ratio of bacteria cultured on high nutrient: low nutrient media decreased with time of starvation. A similar effect on the intestinal microbiota of squid was observed in vivo when the animals were starved. The in vivo starvation of the mouse also produced a decrease in the mean bacterial cell volume which was concurrrent with a promotion of coliform bacteria. A coliform isolate exhibited similar starvation survival characteristics in vitro. From the data obtained from the flounder, squid and mice, it was concluded that components of the large intestinal microbiota exhibited the starvation survival characteristics previously reported for laboratory studies of planktonic bacteria, when exposed to energy- or nutrient-limited conditions.