海洋細菌の無機塩要求性に関する生理学的研究-I
溶菌防御に要求される最小塩類濃度
1976 年 42 巻 3 号 p. 307-313
詳細
1976 年 42 巻 3 号 p. 307-313
No clear-cut criteria for the discrimination of marine bacteria obtained from marine isolates have been found as yet. HIDAKA (1964, 1965), HIDAKA and SAKAI (1965, 1968) divided many isolates into the following three types: M-type (marine type, which requires Na+, K+, Mg2+ and Ca2+ for growth and scarcely grows at 37°C), H-type (halophilic type, which requires only Na+ for growth) and T-type (terrestrial type, which seemingly needs no addition of salt for growth and grows well at 37°C). Subsequently, the present authors subdivided H-type into MH-type (marine halophilic type, which scarcely grows at 37°C) and TH-type (terrestrial halophilic type, which grows well at 37°C), and considered M-and MH-types to be marine bacteria, the M-type especially representing true or specific marine bacteria, and TH-and T-types as terrestrial bacteria. This study was undertaken to demonstrate the theoretical basis of this typing method and the validity of its criteria to discriminate between marine bacteria and non-marine bacteria. The type-specificity of the inorganic salt requirement among the four types was studied by physiological and biochemical investigations.
First, in order to prepare cell-washing and cell-suspending solutions without any excess of salt, the minimum salt solution required to prevent lysis was studied in this paper. Lysis was observed by the decrease of turbidity (O. D. at 610mμ) in cell suspensions and by the leakage of U. V. absorbing materials (O. D. at 260mμ) from cells. The results showed that lysis of M-type was not prevented in any NaCl and KCl solutions, and 21.6%-26.2% ASW (modified Herbst's artificial sea water) was determined as the minimum salt solution to prevent lysis. Lysis of the MH-type was prevented in 2.16%-2.40% NaCl solution, and that of the TH-type was prevented in 0.99%-0.86% NaCl solution, respectively. T-type, however, did not lyze even in distilled water. It was suggested that M-, MH-, TH- and T-types each require a type-specific salt not only for growth but also for lysis prevention.
