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1.
A vitamin B12-producing and hydrocarbon-utilizing bacterium, Corynebacterium simplex, accumulated an appreciable amount of cobalt-porphyrin in cultural filtrates when grown on a n-hexadecane medium containing sufficient amounts of cobaltous sulfate and an appropriate detergent. When grown without the detergent, the cobalt-porphyrin was found only in the cells of the organism. In the latter case, the content of cobalt-porphyrin was comparable to that of vitamin B12 and 7 times lower than that of iron-porphyrin. Though the organism required cobaltous sulfate for optimal growth, the requirement could be efficiently replaced by the supplementation of cobalt-porphyrin and partly of vitamin B12. The porphyrin moieties of extra- and intracellular cobalt-porphyrin were identified as coproporphyrin III in both cases. 相似文献
2.
Microorganisms were continuously cultivated in multistage column consisting of ten perforated plate sections to which medium and air were supplied concurrently from the bottom. At steady state the cell concentration in the various stages was gradationally differentiated from the bottom to the top in the direction of medium flow. RNA content per unit cell concentration at each sage was determined. The cells in the lower stages were higher in RNA content than those from the upper stages. Wash out was observed to occur in the column at dilution rates which do not result in wash out in a single stage chemostat system. A study of the flow characteristics revealed that the overall performance of the plate column was equivalent to that of a multistage system, when hole diameter and hole area to column cross sectional area ratio were properly selected. This was true even in highly aerated conditions. These results indicated that the perforated plates in the column hindred intermixing through the plates, and that each stage functioned as an independent stirred vessel. Industrial and research application of this type fermentor was discussed. 相似文献
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Yoshio Oka Tetsuro Kobayashi Shoichi Fujita Nariaki Matsuura Shigeru Okamoto Hideki Asakawa Atsuo Murata Takesada Mori 《In vitro cellular & developmental biology. Animal》1993,29(7):537-542
Summary A human anaplastic thyroid cancer cell line K-119, derived from a 77-yr-old woman who had developed marked neutrophilia and
underwent surgery for anaplastic thyroid cancer, has been established. The spindlelike and polygonal cells in shape are stably
proliferating since the beginning of its culture 2 yr ago. The cells grow rapidly and the population doubling time is 26 h.
The chromosomes show many abnormalities and many marker chromosomes have been observed. Heterotransplantation of the cells
into nude mice has resulted in the formation of tumors that are histologically interpreted as anaplastic cancer. The most
noteworthy characteristics of the cell line are the many Ki-67-positive cells (86.3%) and that the cell line spontaneously
secretes granulocyte colony-stimulating factor (G-CSF) and releases increased amounts of G-CSF in response to the stimulation
of tumor necrosis factor, interleukin 1α, and interleukin 1β. The conditioned medium obtained from K-119 cells contains an
autocrine factor stimulating the proliferation of themselves. 相似文献
7.
利用脂肪酶在有机溶剂中催化对映选择性酯化反应对外消旋薄荷醇进行了有效的光学拆分。对分别使用酸酐和相应的游离羧酸作酰基给体时的反应性能进行了比较。发现酸酐的反应性远高于对应的游离羧酸,但在酶的催化作用下酸酐易水解成为游离羧酸;在微水系统中使用过高浓度的酸酐会导致酶缺水而失活,同时会促进手性醇的非选择性酯化,从而降低产物的光学纯度。然而,在连续流加丙酸酐的半批式反应系统中,所有这些缺点均可有效地克服。与使用游离丙酸的批式反应系统相比,dl-薄荷醇的反应时间缩短了一半,酶的稳定性大幅度提高,而产物l薄荷醇酯的光学纯度不相上下(>98%e)。 相似文献
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Summary The positive regulator gene (phoB) for alkaline phosphatase of Escherichia coli was cloned into the EcoRI site of pBR322 from the E. coli chromosome by a shotgun method. phoB was then constructed in vitro by replacing the C fragment of gtC by the phoB chromosomal fragment obtained from the hybrid plasmid. When the phoB mutant was lysogenized by phoB, the lysogen became PhoB+. The integration site of the phage was identified by P1 phage transduction to be around phoB site on the chromosome. From these results, we conclude that the cloned gene is phoB and not a gene which suppresses phenotypically phoB mutation when it is in a multi-copy state. The restriction map was constructed. Based on this information, several PhoB deletion plasmids and smaller PhoB+ plasmids were constructed in vitro. By examining PhoB phenotype when these plasmids were introduced into phoB mutant, we could define the phoB gene locus in 2 kb on the restriction map of the cloned chromosomal fragment. Cells carrying the multi-copy phoB gene produced alkaline phosphatase qualitatively under normal phosphate regulation. The phoB gene product was identified by the maxicell method as a protein with a molecular weight of approximately 31,000 daltons. 相似文献
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Tetsuo Omata Noritada Iwamoto Tomio Kimura Atsuo Tanaka Saburo Fukui 《Applied microbiology and biotechnology》1981,11(4):199-204
Summary
dl-Menthyl succinate was successfully hydrolyzed stereoselectively by Rhodotorula minuta var. texensis cells entrapped within photo-crosslinked or polyurethane resin gels in water-saturated n-heptane. The hydrolyzed product was found to be pure l-menthol. The catalytic activity of the immobilized cells, especially those entrapped in urethane polymers, was far more stable than that of the free cells. The half-life of the polyurethaneentrapped cells was estimated to be 55–63 days in the organic solvent.Dedicated to the 65th birthday od Professor Dr. G. Manecke 相似文献