Studies on the comparative physiology of the aerobic photosynthetic bacteria

1.分类、分布及特征：目前已鉴定的好氧光合细菌为兼性甲基磷和海洋细菌。对前者提出了原单胞菌属，对后者提出了红杆菌属。许多不明海洋细菌被认为是好氧光合作用细菌。生化特性：(1)所有供试的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-叶绿素蛋白复合体，均与普通光合细菌相似。在大多数好氧光合细菌中都发现了不能将光能传递给细菌叶绿素的游离类胡萝卜素，这些色素在结构上与普通光合细菌的不同。E.och114中的一种可溶性细胞色素的氨基酸序列与E.…中的细胞色素c_2、细胞色素氧化酶(AA_3)的氨基酸序列高度同源。提纯了更多的长臂，它由一个亚基组成。(2)分别从红色原细菌NR-1和E.Och 114中分离纯化了-氨基乙酰丙酸合成酶和胆红素原合成酶。这表明好氧光合细菌中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在厌氧条件下不发生光合作用。在三甲胺-N-氧化物、硝酸盐和亚硝酸盐等“辅助氧化剂”存在下，光合作用在厌氧条件下得以恢复。这些结果表明，在厌氧条件下，电子传递系统中氧化还原平衡的调节，尤其是光合作用的调节不起作用。(2)E.Och 114在这些辅助氧化剂存在下厌氧生长。在硝酸盐存在的情况下，该菌在厌氧生长过程中会产生一氧化二氮，表明该菌具有反硝化活性。在光照和黑暗条件下的厌氧生长过程中都没有细菌叶绿素的形成。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。较少

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