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The production of L-lysine fromDL-α-amino-ε-caprolactam (DL-ACL) by new strains producingL-α-amino-ε-caprolactamase and aminocaprolactam racemase is described. Optimal conditions for hydrolysis ofL-ACL byCryptococcus sp. and for racemization of ACL by cells of a strain isolated in nature and identified asPseudomonas sp. were determined. Synthesis ofL-α-amino-ε-caprolactamase is induced byDL-ACL orL-lysine with the same effectivity. A positive effect of phosphates (potassium salts) on reduction of the induction lag was
detected, the synthesis of this enzyme was found to be repressed by glucose and some possibilities of the reversion of this
repressive effect were demonstrated. Under conditions optimal for the production of both enzymes a quantitative theoretical
conversion of 10 % aqueousDL-ACL toL-lysine by a mixture of native cells in a mass ratio of 1: 2 (producer of ACL-hydrolase to producer of ACL-racemase) occurred
in 8 h at 40 °C and pH 8.0 相似文献
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The development of spinal cord supports (bony thickenings which extend into the vertebral canal of vertebrae) in primitive (Salamandrella keyserlingii) and derived (Lissotriton vulgaris) salamanders were described. The spinal cord supports develop as the protuberances of periostal bone of the neural arches in the anteroproximal part of the septal collagenous fibers which connect a transverse myoseptum with the notochord and spinal cord, in the septal bundle inside the vertebral canal. Spinal cord supports were also found in some teleostean (Salmo salar, Oncorhynchus mykiss) and dipnoan (Protopterus sp.) fishes. The absence of the spinal cord supports in vertebrates with cartilaginous vertebrae (lampreys, chondrichthyan, and chondrostean fishes) corresponds to the fact that the spinal cord supports are bone structures. The absence of the spinal cord supports in frogs correlates with the lack of the well developed septal bundles inside the vertebral canal. The spinal cord supports are, presumably, a synapomorphic character for salamanders which originated independently of those observed in teleostean and dipnoan fishes. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc. 相似文献
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Pavel Husák 《Folia Geobotanica》1982,17(4):421-426
Scattered green was studied in Czechoslovakia by means of the air multispectral photography and of the field observation. According to various repartition and canopy 19 structural types of seattered green were derived. 相似文献
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An HTY medium osmotically stabilized with 0.5 M D-glucitol was used for regeneration ofBacillus subtilis protoplasts. The application of glucitol as osmotic stabilizer allows simultaneous selection of cells resistant to kanamycin
to be made since this antibiotic is not inactivated by glucitol when added to the regeneration medium. 相似文献
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