Microbiology Section, Division of Biology, and Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506.
Appl Environ Microbiol. 1986 Nov;52(5):1060-7. doi: 10.1128/aem.52.5.1060-1067.1986.
Rhizobium trifolii 0403 was treated with 16.6 mM succinate and other nutrients and thereby induced to grow in nitrogen-free medium. The organism grew microaerophilically on either semisolid or liquid medium, fixing atmospheric nitrogen to meet metabolic needs. Nitrogen fixation was measured via N incorporation (18% N enrichment in 1.5 doublings) and acetylene reduction. Nitrogen-fixing cells had a K(m) for acetylene of 0.07 atm (ca. 7.09 kPa), required about 3% oxygen for optimum growth in liquid medium, and showed a maximal specific activity of 5 nmol of acetylene reduced per min per mg of protein at 0.04 atm (ca. 4.05 kPa) of acetylene. The doubling time on N-free liquid medium ranged from 1 to 5 days, depending on oxygen tension, with an optimum temperature for growth of about 30 degrees C. Nodulation of white clover by the cultures showing in vitro nitrogenase activity indicates that at least part of the population maintained identity with wild-type strain 0403.
三叶草根瘤菌 0403 用 16.6mM 琥珀酸盐和其他营养物质处理，从而在无氮培养基中诱导生长。该生物在半固体或液体培养基中微需氧生长，固定大气氮以满足代谢需求。通过 N 掺入（1.5 倍增中 18%的 N 富集）和乙炔还原来测量固氮。固氮细胞对乙炔的 K(m)为 0.07 大气压（约 7.09 kPa），在液体培养基中最佳生长需要约 3%的氧气，在 0.04 大气压（约 4.05 kPa）乙炔下，乙炔还原的最大比活度为每毫克蛋白每分钟 5 毫摩尔。在无氮液体培养基中的倍增时间从 1 天到 5 天不等，具体取决于氧气张力，生长的最适温度约为 30 摄氏度。具有体外固氮酶活性的培养物对白三叶草的结瘤表明，至少部分种群保持与野生型菌株 0403 的同一性。
