Endogenous Inhibitors for Pollen Germination and Pollen Tube Elongation in Pinus densiflora SIEB,et Zucc. |
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Authors: | Satoshi Kobayashi Tetsuo Ozawa Hiroshi Imagawa |
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Institution: | Institute of Applied Biochemistry, The University of Tsukuba, Sakura-mura, Niihari-gun, Ibaraki 305, Japan |
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Abstract: | Sulfur metabolism in Cephalosporium acremonium was investigated using a mutant, 8650+/ OAH?/SeMeR, which could not convert cysteine or inorganic sulfur to methionine. The production of cephalosporin by the mutant depended on the amount of S-sulfocysteine in a chemically defined medium supplemented with a low level of methionine sufficient to support optimal growth. S-Sulfocysteine was detected in an extract of cells grown in the presence of sodium thiosulfate and l-serine. Furthermore, an NADPH-linked reduction of S-sulfocysteine to cysteine was demonstrated in a cell-free extract. These facts suggest that S-sulfocysteine is a direct precursor in cysteine biosynthesis in C. acremonium and an alternative pathway involving the compound is one of the most important ones in cephalosporin C production by this fungus. |
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