Starvation-survi[v]al studies on a marine Vibrio sp. and other selected marine bacteria

Graduation date: 1983The starvation-survival patterns of 16 freshly isolated open\ud ocean bacteria and in a psychrophilic Vibrio sp., Ant-300, were\ud determined. These isolates displayed three survival patterns as\ud determined by viable cell count. These were (a) a rapid increase\ud followed by a decrease to a constant value (pattern of Ant-300 and\ud 7 isolates), (b) a rapid decrease to a constant value (4 isolates),\ud (c) a gradual increase to a constant value (5 isolates). Isolates\ud changed shape with most becoming coccobacilli by 8-9 mo\ud starvation. All isolates decreased in size, thereby increasing\ud their surface to volume ratio.\ud One isolate from each starvation survival pattern and Ant-300\ud were incubated under simulated open ocean conditions with\ud [¹⁴C]glutamic acid and monitored for respiration and cellular in\ud corporation of radiolabel. In each case a rapid linear respiration\ud and cellular incorporation of labeled glutamic acid was seen. Physiological studies on Ant-300 were conducted both during 6\ud weeks starvation and recovery (the addition of nutrients) from\ud starvation. During long-term starvation, macromolecules on a per\ud cell basis rapidly decreased as cells fragmented (division without\ud biomass increase) in the first 24-48 h. At one week starvation,\ud the quantity of protein and DNA became constant whereas the level\ud of RNA increased. Also after one week, a small peak in activity\ud was seen in endogenous respiration, respiration potential\ud (substrate added), and ATP level per viable cell; and glutathione\ud was resynthesized after an initial decline when appropriate amino\ud acids were present.\ud After recovery from starvation Ant-300 displayed characteristics of both exponential and growing cells. Individual cell\ud size and macromolecules increased exponentially with the addition\ud of nutrients after lag periods which related to the prior length of\ud starvation. Cells of Ant-300 displayed greater degrees of dormancy\ud with increased starvation time.\ud Protein fingerprint patterns formed by two dimensional gel\ud electrophoresis showed changes in individual protein spots during\ud long-term starvation. Cells grown under pressures comparable to\ud those from which Ant-300 was isolated, showed similar protein\ud patterns but lower concentrations when pressures higher than 100\ud atmospheres were employed. Cells recovering from starvation also\ud showed much the same pattern as those under other conditions of\ud growth, indicating that [³⁵S]methionine is synthesized into all the\ud proteins of a growing cell