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31.
Plant components with bio-antimutagenic activity were screened on UVC (254 nm)-induced mutagenesis using E. coli B/r WP2. The components with a pyrogallol moiety including gallic acid, (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG) reduced the mutation induction, but other components such as caffeic acid, chlorogenic acid and quercetin did not. The above compounds with a pyrogallol moiety were also effective on UVAB (295-400 nm)-induced mutagenesis, while they showed little effect on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced mutagenesis. As this bio-antimutagenic effect was not seen in the DNA excision-repair-deficient strains WP2s and ZA159, the activity by the above plant components might be based on the promotion of the excision-repair system in E. coli B/r WP2.  相似文献   
32.
Development of fin-supports and fin-rays was observed in larval and juvenileChanos chanos, Chondrification of the caudal complex started at 4.70 mm SL. Ossification of the caudal elements started at 7.80 mm SL and was nearly completed at about 30 mm SL. Cartilaginous fusion of caudal elements, which occurs in hypurals of higher teleostean fishes but is not seen in lower teleosts, was observed between the neural arch of the preural centrum 1 and that of the ural centrum 1 via a small cartilage bridging the distal tips of the two arches. Caudal finrays began to develop at 6.60 mm SL, and an adult complement of principal rays was attained at 7.35 mm SL. Dorsal and anal pterygiophore elements were first evident at 6.70 mm and 6.65 mm SL, respectively. All proximal radiais were formed at 8.15 mm SL in both fins. Formation of dorsal and anal fin-rays started simultaneously at 8.60 mm SL, and adult fin-ray complements were attained at 10,00 mm and 10.70 mm SL, respectively. In the pectoral fin, the cleithrum, coraco-scapular cartilage and blade-like cartilage (fin plate) had already been formed at 4.65 mm SL. The mesocoracoid was observed to originate from the coraco-scapular cartilage and become detached from it in the course of ossification. Pectoral fin-ray formation started at 13.80 mm SL and was completed in number of rays at 20.00 mm SL. In the pelvic fin, the basipterygium was first evident at 13.00 mm SL. Pelvic fin-rays appeared at 13.80 mm SL and attained their adult count at 17.15 mm SL.  相似文献   
33.
Murine T cell replacing factor (TRF) was purified from a cellfree supernatant of a T cell hybridoma (B151K12) that constitutively produces TRF. Two assay systems for TRF activity were employed: 1) induction of anti-DNP IgG PFC responses in cultures of splenic B cells from DNP-KLH-primed BALB/c mice, and 2) induction of IgM PFC in chronic B cell leukemic cells (BCL1). The purification scheme consisted of ammonium sulfate precipitation, DEAE-cellulose chromatography, Blue-Sepharose chromatography, hydroxylapatite chromatography, gel permeation with fast protein liquid chromatography (FPLC), and disc polyacrylamide gel electrophoresis. Overall, TRF was purified approximately 34,000-fold with a maximum 3.8% recovery of activity, and the specific activity of the purified TRF was approximately 9.6 X 10(4) U/mg. The TRF that is active in these systems is distinct from the other lymphokines such as IL 1, IL 2, BCGFI (now known as BSFp1), and gamma-interferon. The TRF is extremely hydrophobic, with an apparent m.w. of 50,000 to 60,000 on gel permeation chromatography and 18,000 on SDS-PAGE under reducing conditions. Highly purified B151-TRF abrogated the activity by treatment with trypsin but not with RNase. Moreover, it bound to lima bean agglutinin-Sepharose specific for N-acetylgalactosamine residues, indicating that B151-TRF is a glycosylated glycoprotein containing N-acetylgalactosamine residues. The role of N-acetylgalactosamine residues on TRF activity was additionally substantiated by the fact that the addition of appropriate amounts of N-acetylgalactosamine in the assay systems for TRF preferentially induced a profound suppression for TRF-mediated PFC responses.  相似文献   
34.
Summary In order to determine the active site of penicillin-binding protein 3 of Escherichia coli (PBP3), the serine residue at position 307 was replaced with alanine, threonine or cysteine by oligonucleotide-directed site-specific mutagenesis. Since a unique BanII site exists at the position corresponding to serine-307, BanII digestion of the plasmid DNA after mutagenesis resulted in significant enrichment of the mutant plasmids. For mutagenesis, the gene coding for PBP3 (ftsI) was inserted into the expression cloning vector pIN-IIB. The hybrid protein produced was able to bind penicillin while mutant PBP3 in which serine-307 was replaced with either alanine or threonine did not lead to any detectable binding. However, contrary to the report of Broome-Smith et al. (1985) thiol-penicillin-binding protein 3, in which serine-307 was replaced with cysteine, was still able to bind penicillin. Replacement of serine-445 with an alanine residue had no effect on penicillin binding to PBP3.  相似文献   
35.
Results of measurement of urinary steroid metabolite profile using gas chromatographic analysis in eight patients with adrenocortical tumors, i.e. 3 adenomas with Cushing's Syndrome, one adenoma with virilization, one adenoma without clinical manifestations, one carcinoma with Cushing's syndrome and virilization, one carcinoma with Cushing's syndrome and feminization, and one carcinoma without endocrinological symptoms, are reported. A unique pattern dominated by 5 beta and 11 beta-hydroxy steroid metabolites was confirmed in five patients with Cushing's syndrome consisting of three cases with adenomas and two with carcinomas. Excessive 3 alpha, 17 alpha, 21-trihydroxy-5 beta-pregnan-20-one (tetrahydro-11-deoxycortisol, THS) and delta 5-pregnene-3 beta, 11 alpha, 20 alpha-triol (delta 5-pregnenetriol) values were found in all three carcinomas including a nonfunctional carcinoma. These findings would strongly suggest the tumor to be a carcinoma, although excessive excretion of THS and delta 5-pregnenetriol was detected in one patient with a large adenoma associated with virilization. One patient with carcinoma was responsive to ACTH stimulation while the remainder show almost no response to exogenous ACTH. Urinary steroid profiling using gas chromatographic analysis, especially the values for THS and delta 5-pregnenetriol, appears to be a useful method to use in detecting these steroid metabolic characteristics in patients with adrenocortical carcinoma.  相似文献   
36.
A hybridoma cell line producing mouse monoclonal antibody against pig kidney Na,K-ATPase was established. The antibody, named 38 (mAb38, IgG1), was purified from mouse ascites fluid by chromatography on a protein A-Sepharose column. Antigens immobilized on microplate wells with p-benzoquinone were used for titer assays. mAb38 cross-reacted with both dodecyloctaethyleneglycol monoether (C12E8)-solubilized enzyme and membranous sodium dodecyl sulfate (SDS)-treated enzyme from kidney with high affinity (50% binding = 0.6 nM). However, the antibody bound to neither alpha- nor beta-subunit separated by preparative SDS-polyacrylamide gel electrophoresis (PAGE). The stoichiometry of antibody binding to the purified enzyme was estimated to be about 0.86 mol of IgG per mol of alpha beta-protomer. Na,K-ATPase proteins were recovered from a column of mAb38-coupled Affi-Gel by elution with pH 3 buffer when C12E8-solubilized kidney enzyme or detergent extracts of brain microsomes were applied to it, confirming that the mAb is directed to Na,K-ATPase. mAb38 at saturation level concentrations had no effect on kidney Na,K-ATPase activity or on ouabain-sensitive Rb uptake in erythrocytes. In an immunofluorescence study, the antibody bound to intact erythrocytes much more strongly than control IgG1 (mAb50c), but the extent of the antibody binding to inside-out vesicles under hypotonic conditions was lower than that of the control. Most of the antibody binding activity remained when the kidney enzyme was treated with sialidase. These results suggest that this mAb38 was raised against an intact conformation of a cell-surface-exposed site of Na,K-ATPase.  相似文献   
37.
Aldehyde reductases from several mammalian and avian tissues transferred the pro-4R hydrogen of NADPH to the substrate, whereas the stereospecificity of carbonyl reductases was not uniform being correlated with the ability to catalyze the oxidoreduction of hydroxysteroids.  相似文献   
38.
On the basis of anatomical and physiological results of the vertebrate retina, a method is proposed for analysing the respective fields of ganglion cells in the cat retina. In the model, we assume the following: (a) Ganglion cells receive their input from bipolar and/or amacrine cells. (b) The nonlinearity of ganglion cell responses is due to the activities of transient type amacrine cells. The method has been proved to be effective. According to the results of this investigation, the receptive field properties of X type and Y type ganglion cells are heterogeneous. Thus, it may be considered that their receptive fields consist of center and surround mechanisms. The receptive field properties of X-cells are almost linear and the X-cells seem to receive most of their input from bipolar cells. On the other hand, the ones of Y-cells are highly nonlinear. Consequently, it is conceivable that the Y-cells receive their input mainly from transient type amacrine cells.  相似文献   
39.
Characterization of Fe2+-activated acid phosphatase in rat epidermis   总被引:1,自引:0,他引:1  
A particulate acid phosphatase (EC 3.1.3.2, orthophosphoric monoester phosphohydrolase (acid optimum)) was extracted in 1 M KCl, from 2-day rat epidermis. The enzyme has a Mr of 32,000, but two forms, F1 and F2 with pI values of 8.6 and 8.3, respectively, were identified while the pI values of other acid phosphatases soluble in sucrose and Triton X-100 were all acidic. F1 and F2 also differed from other epidermal acid phosphatases because they were (a) activated by Fe2+ and reducing agents, (b) showed immunological cross-reactivity with purple acid phosphatase of rat spleen and (c) dephosphorylated phosvitin and alpha-casein even though they had rather high Km values.  相似文献   
40.
An acid phosphatase species which is activated by Fe2+ was purified 3,700-fold from rat spleen by chromatography on columns containing Blue-Sepharose, concanavalin A-Sepharose, Sephadex G-100, and CM-Sephadex. The enzyme hydrolyzed aryl phosphates, nucleoside di- and triphosphates, phosphoproteins, and thiamine pyrophosphate with Km values of 10(-4) to 10(-3) M at an optimal pH of 5.0-5.8. Co-purification of the acid phosphatase and acid phosphoprotein phosphatase indicated that they were identical. The purified enzyme was glycoprotein in nature, showing four heterogeneous forms on acid polyacrylamide gel electrophoresis (pI values, 7.8, 8.0, 8.3, and 8.5), but it gave a molecular weight of 33,000 on sodium dodecyl sulfate-gel electrophoresis and gel permeation chromatography. The enzyme had a purple color (lambda max 545 nm) and contained 2 iron atoms per enzyme molecule. Among reductants, ascorbic acid and Fe2+ were the best activators, although their combined effect was not additive. Fe2+ and ascorbic acid both changed the purple enzyme into the same active form (lambda max 515 nm), giving almost the same kinetic constants for substrates and for inhibitors such as molybdate, phosphate and fluoride. However, low concentrations of Fe2+, from 0.01 mM to 1.0 mM, immediately and reversibly activated the enzyme, whereas high concentrations of ascorbic acid over 1 mM were required for maximal activation, which was slow and irreversible.  相似文献   
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