Studies on the comparative physiology of the aerobic photosynthetic bacteria

1. 分类、分布及特点：目前已鉴定的需氧光合细菌为兼性甲基藻菌和海洋细菌。前者命名为原单胞菌属，后者命名为红杆菌属。许多未知的海洋细菌被认为是需氧光合细菌。生化特性：(1)所有被试好氧光合细菌均含有细菌叶绿素a和光化学反应中心以及捕光细菌叶绿素蛋白复合物，与普通光合细菌相似。在大多数好氧光合细菌中发现了不将光能传递给细菌叶绿素的非结合类胡萝卜素色素，这些色素在结构上与普通光合细菌不同。其中一种可溶性细胞色素的氨基酸序列与细胞色素c_2具有高度的同源性。对E. ... More longus中含有1个亚基的细胞色素氧化酶（aa_3）进行了纯化。(2)分别从橡胶蛋白氨基杆菌NR-1和E. OCh 114中纯化得到-氨基乙酰丙酸合成酶和卟绿胆色素原合成酶。这表明好氧光合细菌的细菌叶绿素的生物合成途径与普通光合细菌相似。生理特性：(1)E. OCh 114在厌氧条件下不进行光合作用。在三甲胺- n -氧化物、硝酸盐和亚硝酸盐等“辅助氧化剂”存在的情况下，在厌氧条件下恢复了光合作用。这些结果表明，在厌氧条件下，电子传递系统，特别是光合作用的氧化还原平衡的调节并不起作用。(2) E. OCh 114在这些辅助氧化剂的存在下厌氧生长。在硝酸盐的存在下，厌氧生长过程中产生氧化亚氮，表明该细菌具有反硝化活性。光照和黑暗条件下厌氧生长均无细菌叶绿素生成。分子氧对细菌叶绿素形成的调控可能与普通光合细菌不同。少

1. Taxonomy, distribution and characteristics: The aerobic photosynthetic bacteria identified so far were facultative methyloprophs and marine bacteria. The genus, Protomonas,for the former and the genus, Erythrobacter, for the latter were proposed. Many unidentified marine bacteria suggested to be the aerobic photosynthetic bacteria.2. Biochemical characteristics: (1) All of the aerobic photosynthetic bacteria tested contained bacteriochlorophyll a and photochemical reaction center and the light-harvesting bacteriochlorophyll protein complexes, all similar to those of common photosynthetic bacteria. In most of the aerobic photosynthetic bacteria unbound carotenoid pigments, which did not transfer light energy to bacteriochlorophyll, were found and these pigments were structurally different from those in the common photosynthetic bacteria. Amino acid sequence of one of the soluble cytochromes in E. OCh 114 had the high homology to that of cytochrome c_2. Cytochrome oxidase (aa_3) in E. … More longus, which consisted of one subunit, was purified. (2) -Aminolevulinic acid synthase and porphobilinogen synthase were purified from Protaminobacter ruber NR-1 and E. OCh 114, respectively. This suggested that biosynthetic pathway of bacteriochlorophyll in the aerobic photosynthetic bacteria was similar to that of the common photosynthetic bacteria.3. Physiological characteristics: (1) Photosynthesis of E. OCh 114 did not take place under anaerobic conditions. In the presence of "auxiliary oxidants" such as trimethylamine-N-oxide, nitrate and nitrite, the photosynthesis was restored ubder anaerobic conditions. These results suggested that the regulation of the redox balance in the electron transport system, especially of photosynthesis, did not operate under anaerobic conditions. (2) E. OCh 114 grew anaerobically in the presence of these auxiliary oxidants. In the presence of nitrate, nitrous oxide was evolved during anaerobic growth, suggesting that this bacterium had the denitrification activity. There was no bacteriochlorophyll formation during the anaerobic growth in both the light and dark. The regulation by molecular oxygen on bacteriochlorophyll formation may be different from that in the case of the common photosynthetic bacteria. Less