PSYCHROPHILIC BACTERIA FROM ANTARCTICA

Abstract

NMicroorganisms are commonly present in the antarctic region. McLean (1918) isolated gram-positive cocci and gram-positive and gram-negative sporeforming and nonsporeforming rod-shaped bacteria from snow and ice and in as-sociation with frozen algae at Adelie Land near the South Pole. Also, Darling and Siple (1941) isolated 178 bacterial cultures from the snow, ice, water, plant debris, and soil of Antarctica. Of these, 117 cultures were aerobic, sporeforming rods, 45 nonsporeforming rods, and 16 cultures of cocci. Recently, Sieburth (1959) found aerobic, slow or negative lactose-fermenting, gram nega-tive rods and also obligate anaerobes in the gastrointestinal tracts of antarctic birds. Sur-prisingly, however, none of these investigators attempted to determine whether any of their strains were psychrophiles, i.e., bacteria able to grow at 0 C (Ingraham and Stokes, 1959). If present, psychrophilic bacteria would be of prime importance in the cycles of matter inlAntarctica. During summer months in Antarctica, tempera-tures hover around 0 C (McLean, 1918; Darling and Siple, 1941). Such temperatures would per-mit considerable growth and other activities of psychrophiles. In contrast, mesophilic bacteria would not grow and would be virtually inactive at these low temperatures. Accordingly, an attempt was made to isolate psychrophilic bacteria from antarctic samples.