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871.
This paper describes the scale-up from 0.1 to 100 liter of the unit process based on 3-mm-diameter glass spheres for the growth of BHK monolayer cells. The production of four strains of FMD virus at the 0.1-, 10-, and 100-liter scales was examined. Cell growth was estimated from measurements of the concentration of glucose in the growth medium, while the release of virus was inferred from measuring the concentration of LDH in the culture supernatant fluid. The yields of virus at 0.1-, 1-, and 10-liter scales were similar but that from the 100-liter version was somewhat lower. The reason for this lower yield and the method used to overcome it over outlined. 相似文献
872.
T Yoshikawa H Terayama 《Comparative biochemistry and physiology. A, Comparative physiology》1984,77(1):39-44
Pancreatectomy as well as thyroparathyroidectomy resulted in the quick disappearance of a serum factor (stimulating cathepsin D release from lysosomes in vitro) from the rat or mouse blood. Extirpation of other organs such as duodenum, stomach, spleen, kidney, submaxillary gland, testis, adrenal gland or hypophysis, showed no effect on the serum factor level. Glucagon (but not insulin or thyroxine) given to the pancreatectomized animals restored the serum factor level in a dose-dependent manner. The serum factor-like activity was detected only in the parathyroids (but not thyroid), and the release of activity from parathyroid-slices was stimulated by glucagon, suggesting that the parathyroid may produce and/or secrete the serum factor under the influence of glucagon. 相似文献
873.
Phase-sensitive two-dimensional nuclear Overhauser effect spectra of [d(GGTATACC)]2 in aqueous deuterium oxide solution at four mixing times were quantified to give all nonoverlapping cross-peak intensities. A structural model for [d(GGTATACC)]2 was built in which the GG- and -CC moieties were in the B-DNA form, while the middle -TATA- moiety was in the wrinkled-D form (BDB model). This model was subjected to energy refinement by molecular mechanics calculations with the program AMBER. Counterions (Na+) were added to neutralize the charges, and water molecules were placed bridging across the minor groove. A complete relaxation matrix analysis was used to calculate two-dimensional nuclear Overhauser effect spectra of [d(GGTATACC)]2 from the above models (before and after energy refinement) and from four other [d(GGTATACC)]2 structural models: regular A, crystalline A, regular B, and energy-minimized B. Among them, the energy-minimized BDB model yielded a set of theoretical spectra that gave the best fit to the experimental spectra. It was also the energetically most stable. Therefore, it is a good representation of the ensemble- and time-averaged structure of the octamer in solution. This model has backbone torsion angles similar to those of B-form DNA in the GG- and -CC moieties and torsion angles similar to those of wrinkled D form DNA in the -TATA- moiety. The base stacking and base pairing are not interrupted at the junctions between the two structural moieties. Its minor groove is narrower than that of B DNA, and the solvent-accessible surface of the minor groove forms a closed hydration tunnel in the middle -TATA- segment. 相似文献
874.
Self-splicing of group II introns in vitro: lariat formation and 3' splice site selection in mutant RNAs 总被引:10,自引:0,他引:10
Deletion or substitution of the branch A residue in group II intron bl1 significantly reduces splicing activity; yet, residual exon ligation is correct, and lariats have their branch points at the normal distance from the 3' end of the intron. Mutations in the sequence facing the branch point also allow residual lariat formation; however, free 3' exons are generated with false 5' termini, all of which are within a UCACA consensus sequence located upstream or downstream of the normal 3' splice site. These results indicate that both the conserved 3' splice site APy and the spatial arrangements in stem 6 are crucial for correct 3' splice site selection. 相似文献
875.
Morphological taxonomy of simple Hyphomycetes is complicated by the frequent occurrence of pleoanamorphism. In some groups
of yeast-like fungi, uncommon synanamorphs are diagnostic. Differences in conidiogenesis do not always delimit natural groups.
Some nomenclatural problems are mentioned, with an emphasis on the need of neotypification. Prospects are sketched for future
taxonomic research. 相似文献
876.
Raj K. Singh Mary F. Ruh Thomas S. Ruh 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,800(1):33-40
In the present study we investigated the binding characteristics of estrogen and antiestrogen-receptor complexes to rabbit uterine chromatin. Activated or nonactivated estrogen receptors were partially purified by DEAE-cellulose chromatography using low (1 mM) or high (10 mM) concentrations of sodium molybdate. Activated [3H]estradiol-receptor complexes showed enhanced binding to chromatin acceptor sites unmasked by 1 M, 4 M and 6 M guanidine hydrochloride. We also examined the chromatin-binding characteristics of the estrogen receptors when bound by the high-affinity triphenylethylene antiestrogen, H1285. The acceptor site activity for the [3H]H1285-receptor complexes was markedly decreased at sites unmasked by 4 M and 6 M guanidine hydrochloride. Further, the nonactivated receptor complexes showed very low binding to deproteinized chromatin. The estrogen-receptor chromatin-acceptor sites were tissue specific and saturable. These chromatin acceptor sites differ in their affinity and capacity (number of binding sites per cell) for the estrogen- and antiestrogen-receptor complexes. Thus, we suggest that the differences in the physiological and physicochemical properties of estrogens and antiestrogens may be related to their differential interaction with uterine chromatin subfractions. 相似文献
877.
878.
Summary Net aerial primary production and accumulation of nutrients by the grasses and nongrasses of the ground layer community of a cerrado vegetation in central Brazil were determined in burnt and unburnt areas. The net aerial primary production of the ground layer community was 327 gm–2 in the unburnt area and only 242 gm–2 in the burnt area during the first year after fire. Grasses contributed 68 to 78% of the aerial biomass of the ground layer in the unburnt area. The live biomass in the burnt and unburnt areas was comparable by the end of the first dry period after the fire. The major part of N, P and K in the aerial biomass was in the grasses. The concentration of all nutrients in the aerial biomass was generally higher in the burnt area during the first year after the fire. 相似文献
879.
Three species of blackflies were found in emergence-trap samples taken overa period of 8 months from a second-order, forested, cold-stenothermal stream in southern Ontario. The emergence phenologies of the two common species, Prosimulium mixtum and Stegopterna mutata, are described and compared with their phenologies in other streams in North America. Hypotheses are presented for the poor faunal diversity and prolonged emergence of the two species in the stream studied. Emergence data are used to describe the pupal distribution in the stream.Wing-length measurements showed a distinct dimorphism in P. mixtum: females were larger than males. Adult size (except of P. mixtum females) varied among sampling sites in the stream and, in the case of S. mutata, this variation was time dependent. 相似文献
880.
Induction of delayed-type hypersensitivity by the T cell line specific to bacterial peptidoglycans 总被引:1,自引:0,他引:1
M Katsuki K Kakimoto S Kawata S Kotani T Koga 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(11):3570-3572
A T cell line specific for the chemically well-defined peptidoglycan of bacterial cell wall, disaccharide tetrapeptide, was established from Lewis rats immunized with the antigen covalently linked to the autologous rat serum albumin. The antigen specificity was examined with various analogues or derivatives of the peptidoglycan. The cell line was reactive to analogues with the COOH-terminal D-amino acid, but least reactive to those with L-amino acid as COOH terminus. Transferring of the T cell line into X-irradiated normal Lewis rats induced delayed-type hypersensitivity in an antigen specific manner. 相似文献