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41.
Sodium- and potassium-activated adenosinetriphosphatase (Na+, K+-ATPase) purified from dog kidney outer medulla was examined by polyacrylamide gel electrophoresis and by photoaffinity labeling with N-(ouabain)-N'-(2-nitro-4-azidophenyl)-ethylenediamine (NAP-ouabain). The large subunit band (alpha-band) split into two bands on the gel after the enzyme was heat-treated in the presence of 1% sodium dodecylsulfate (SDS). Of the two bands (alpha I and alpha II), alpha I had the same electrophoretic mobility as the original band, while alpha II moved slightly faster. Total conversion into alpha II was not observed, about half of the original remaining as alpha I. Below 60 degree C, heat treatment did not produce alpha II. Phenylmethylsulfonyl fluoride did not prevent the appearance of alpha II. Both alpha I and alpha II were labeled with [3H]NAP-ouabain. Nonspecific incorporation of [3H]NAP-ouabain also occurred irrespective of illumination, but it was removed either by diffusion during staining and destaining of the gel or by treatment of the enzyme with trichloroacetic acid. It is tentatively concluded that the splitting of the band reflects some intrinsic differences in situ of the alpha-subunit of dog kidney membrane Na+,K+-ATPase. 相似文献
42.
Satoru Kawamura Tôru Yoshizawa Kazumi Horiuchi Masayoshi Ito Akiko Kodama Kiyoshi Tsukida 《BBA》1979,548(1):147-152
9-cis-Retro-γ;rhodopsin (λmax = 420 nm) was prepared from 9-cis-retro-γ-retinal and cattle opsin. After cooling to liquid nitrogen temperature (77 K), the pigment was irradiated with light at 380 nm. The spectrum shifted to the longer wavelengths, owing to formation of a batho product. This fact indicates that the conjugated double bond system from C-5 to C-8 of the chromophoric retinal in rhodopsin was not necessary for formation of bathorhodopsin. Reirradiation of the batho product with light at wavelengths longer than 520 nm yielded a mixture composed of presumably 9- or 11-cis forms of retro-γ-rhodopsin. These three isomers are interconvertible by light at liquid nitrogen temperature. Thus the retro-γ-rhodopsin system is similar in photochemical reaction at 77 K to cattle rhodopsin system. Each system has its own batho product. Based on these results, it was infered that the formation of bathorhodopsin is due to photoisomerization of the chromophoric retinal of rhodopsin and is not due to translocation of a proton on the ring or on the side chain from C-6 to C-8 of the chromophoric retinal to the Schiff-base nitrogen. 相似文献
43.
Summary
Allium sativum L. (2 n=16) had three types of clones with regard to the number of chromosomes carrying well-defined secondary constrictions: the first type had two secondary constricted chromosomes (type I), the second had three (type II) and the third had four (type III). Silver staining was applied to these three types of cells to determine the number of nucleolus organizing regions (NORs) per cell and to study the relationship between the morphological appearance of the secondary constrictions and the ability of the chromosomes to form nucleoli. Ag-positive regions appeared on two chromosomes in type I, on three in type II and on four in type III. The comparison of Giemsa and Feulgen stained chromosomes with the silver stained ones clearly indicated that the positive reaction with silver occurred exclusively on the secondary constricted regions that responded negatively to both Giemsa and Feulgen staining, indicating that the size of the achromatic secondary constrictions directly reflects the volume of the Ag-positive materials. However, all three types of clones had a maximum of four nucleoli at interphase. Of the four nucleoli, either two or one was extremely small (less than 1 m in diameter) in types I and II respectively. The size variations of the other nucleoli seemed to be positively correlated with those of the Ag-positive regions. This and the observation that the maximum number of nucleoli per cell did not coincide with the number of Ag-positive regions on the metaphase chromosome complement suggest strongly that the NORs responsible for the minute nucleoli cannot be detected on the metaphase chromosomes. The present observations indicate that not all NORs are indicated by the morphological appearance of secondary constrictions. 相似文献
44.
Yuzuru Suzuki Tadashi Yasui Yuji Mino Shigeo Abe 《Applied microbiology and biotechnology》1980,11(1):23-27
Summary A fumaric acid-assimilating obligate thermophile having a high aspartase activity was isolated from soil. The isolate (KP 1041) that grew at 45 to 68 °C was assigned to a strain of Bacillus stearothermophilus. The cell suspensions produced L-aspartate from fumarate and ammonium ion, with the rapidest initial rate at 65 °C and pH 9.5. The Michaelis constant for fumarate was 0.2 M. The cellular aspartase was relatively stable for 18 h at and below 50 °C over a pH range 6.7–8.3 in the presence of ammonium fumarate; this substance protected the enzyme from heat inactivation. The best yield in L-aspartic acid production was achieved at 6 h incubation at 53 °C and pH 8.5, using 0.88 M fumarate, 3.1 M ammonium ion, and the cells at 53 mg dry weight per ml. In this case, 85% of fumarate added was converted into aspartic acid. The structure of the product was determined from its infrared spectrum, specific rotation, melting point and ultimate analysis.Presented at the Annual Meeting of the Agricultural Chemical Society of Japan, Yokohama, April 2, 1977 相似文献
45.
46.
Y Tanigawa A Kitamura M Kawamura M Shimoyama K Fujii Y Kohri I Ueda 《Physiological chemistry and physics》1978,10(5):443-448
Administration of prednisolone and cholate to rats elevated levels of cAMP (adenosine 3',5'-cyclic monophosphate) by 1.5- to 2.0-fold. Compounds such as prednisolone, hydrocortisone, cholate, and deoxycholate were found to be potent inhibitors of partially purified cAMP phosphodiesterase prepared from rat liver. Kinetic analysis showed that the prednisolone inhibition was noncompetitive with a Ki of 8.9 x 10(-4) M. These results suggest that in addition to increasing DNA-dependent RNA polymerase activity in vivo, a large application of glucocorticoid may incur elevation of intracellular cAMP levels. 相似文献
47.
Molecular cloning of bovine leukemia virus DNA integrated into the bovine tumor cell genome 总被引:3,自引:0,他引:3
The bovine leukemia virus (BLV) DNA harbored in the bovine tumor cell genome was cloned in lambda Charon 4A phage. Using either representative or 3' half-enriched BLV cDNA as a blot hybridization probe, clone lambda BLV-1 was shown to carry 9 kb of the BLV genome, flanked by cellular sequences at both ends. Restriction mapping with twelve endonucleases and hybridization of the DNA fragments to BLV cDNA representing a 3'-end portion of the viral genome revealed the presence and precise location of two long terminal repeats (LTRs) and virus-cell junctions. Thus, lambda BLV-1 appears to contain the complete BLV genome and flanking tumor cellular sequences. The restriction map of the cloned BLV proviral DNA closely resembles that previously reported for unintegrated linear proviral DNA, but differs significantly from that of the integrated provirus of another BLV isolate, the difference occurring preferentially in the putative gag and pol genes. 相似文献
48.
49.
To investigate the specific nature of the autologous mixed lymphocyte reaction (AMLR), we applied a method in which mixtures of NY-nonadherent responder cells and NY-adherent stimulator cells were treated with neuraminidase before culture and then cultured to assay the AMLR. This method produced a marked enhancement of DNA replication in the responder cells and the results were reproducible, regardless of the individuals tested. Using this method, we were able to make the following observations regarding the specific nature of the AMLR. (i) The AMLR is an IL-2-independent reaction, as revealed by bioassay to detect the presence of IL-2 by a blocking test using anti-IL-2R sera and as shown by the absence of mRNA for IL-2 in Northern hybridization. (ii) It is also HLA-DR dependent as proven by the fact that anti-DR sera almost completely inhibited the reaction. (iii) The AMLR was also found to induce the generation of activated CD4+ helper T cells in direct response to stimulation by NY-adherent cells, in which HLA-DR antigens were involved. (iv) Also, it induced the generation of CD4-CD8- double-negative (DN) lymphocytes, including gamma delta T cells with a cytotoxic activity against NK-resistant target cells and with a variety of lymphocyte activation markers (CD56, HLA-DR, CD25, transferrin receptors, CD38, and LFA-1). However, the AMLR did not induce the generation of NK cell markers CD16 and CD57. (v) The DN lymphocytes and gamma delta T cells appeared to be generated from the precursors of CD4-CD8- DN cells, in direct response to the stimulator cells. These results strongly suggest that the AMLR may be a phenomenon which induces the proliferative response of gamma delta T cells and their precursors, in addition to that of alpha beta T cells, particularly of CD4+ helper T cells. 相似文献
50.
Self-Nonself Recognition Activity Extracted from Self-Sterile Eggs of the Ascidian, Ciona intestinalis 总被引:1,自引:1,他引:0
Kazuo Kawamura Maki Nomura Tomoko Kameda Hiroko Shimamoto Mitsuaki Nakauchi 《Development, growth & differentiation》1991,33(2):139-148
Eggs of the hermaphrodite, self-sterile ascidian, Ciona intestinalis , were washed with acid seawater (pH 3.2), and the washing solution was then adjusted to pH 8.2. This solution was found to inhibit only the binding of non-autologous sperm to the vitelline coat (VC) of eggs, indicating that it contained self-nonself recognition activity. This activity was heat-stable and insensitive to trypsin, but was destroyed by V-8 protease and α-glucosidase. Both the hydrophobic and hydrophilic components of a lyophilized powder of the extract showed allo-recognizing activity. On TLC, the hydrophobic components gave a major spot of glucose (Glc) and a peptide spot(s) containing mainly glutamic acid and/or glutamine (Glx). The glucosyl conjugate was purified by HPLC and shown to block sperm-egg binding to various extents. Individual peptide subfractions had no inhibitory activity, but in combination they showed inhibitory activity. These findings suggest that the acid extract of Ciona eggs contains a Glc-enriched nonspecific inhibitor of sperm-egg binding, which could be the primary effector of self-incompatibility, and Glx-enriched modulators, which serve as acceptors of allo-sperm. The cooperative interactions of these components may be responsible for the diversity of allo-recognition in Ciona gametes. 相似文献