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91.
A sensitive fluorimetric method for the determination of octopine, a member of opine family, is presented. The method is based on the formation of a fluorescent derivative of octopine with benzoin and the separation by high performance liquid chromatography using a reversed-phase column (Kaseisorb LC ODS-300) within 20 min. The octopine derivative is completely separated from other guanidino compounds including arginine which is generally very high in marine invertebrates. This method gives higher sensitivity, 5 pmol minimum detection, and better reproducibility than the electrophoresis method and colorimetric method. 相似文献
92.
K Tateishi Y Miura T Madarame T Yoshida K Suzuki N Takeichi H Kobayashi Y Matsuoka S Sato 《Regulatory peptides》1991,35(2):95-101
Levels of cholecystokinin (CCK) immunoreactivity and distribution of CCK immunoreactive cells were studied in the cerebral cortex of LEC (Long Evans Cinnamon) rats with hepatic encephalopathy. CCK immunoreactivity in water extract of cerebral cortex of LEC rats with hepatic encephalopathy (n = 7) was 41.5 +/- 2.6 (mean +/- S.E.M. pmol/g wet wt.) and that of LEC rats without encephalopathy (n = 8) was 67.1 +/- 6.9, the difference being significant (P less than 0.01). CCK immunoreactive cells assessed by immunohistochemistry were also markedly decreased in the cortex of LEC rats with hepatic encephalopathy of stage IV. Thus, CCK reduction was observed in the cerebral cortex of LEC rats with hepatic encephalopathy which are provided as a model for analysis of the pathogenesis of acute hepatic encephalopathy. 相似文献
93.
To examine the effects of aging on the density and distribution of somatostatin receptors (SS-R) in the rat brain, receptor autoradiography for SS-R was carried out in rats aged 3 and 24 months using 125I-labeled Tyr11-SS-14. Autoradiograms were quantitatively assessed by an image analyzer to evaluate changes in the expression of SS-R due to senescence. Statistically significant decreases in SS-R binding were found in specific regions of the brains of senescent rats as compared to young adult rats. The regions affected included the periaqueductal gray matter (73% loss versus young adult rats), the interpeduncular nucleus (73% loss), the pontine nucleus (63% loss), the superior colliculus (46% loss), the ventral tegmental area (46% loss), the temporal cortex (39% loss), the frontal cortex (34% loss), the hippocampus (33% loss), the amygdala (27% loss) and the claustrum (26% loss). There was no significant change in SS-R expression in the spinal cord with aging. Significant reductions in SS-R binding in these brain regions may be involved in the impairment of sensory and cognitive function that can occur with aging. 相似文献
94.
Y Furuya H Shirasawa N Sato Y Watabe B Simizu J Shimazaki 《The Journal of steroid biochemistry and molecular biology》1992,42(6):569-574
Shionogi Carcinoma 115 (SC 115) is an androgen-dependent mouse tumor. Chiba Subline 2 (CS 2) is an androgen-independent subline derived from SC 115. CS 2 contains androgen receptors (AR), but is refractory to androgen and does not exhibit androgen-related responses which are observed in SC 115. In the present study the structure and function of AR in SC 115 and CS 2 are examined using cloned cells. There were no gross rearrangements or deletions in the AR genes of these cell lines when compared by Southern blot analysis with the AR gene in the mouse seminal vesicle. SC 115 and CS 2 expressed AR mRNA of normal size. When the cDNA containing DNA- and androgen-binding domains of the AR genes of both cell lines were amplified by polymerase chain reaction, no mutations were found in these regions. SC 115 and CS 2 were transfected with a plasmid containing a long terminal repeat of mouse mammary tumor virus linked to the chloramphenicol acetyltransferase (CAT) gene. Androgen stimulation of these transfectants resulted in equal elevation of CAT activity. These results indicated that the androgen-independent CS 2 contained functionally normal AR which were identical to those in the androgen-dependent parent tumor. 相似文献
95.
A convenient approach to the synthesis of medium size oligodeoxyribonucleotides by improved new phosphite method.
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Improvement of the new phosphite method for the synthesis of oligodeoxyribonucleotides using the deoxyribonucleoside 3'-bis(1,1,1,3,3,3- hexafluoro-2-propyl) phosphite unit has been carried out via the hydrolysis and capping steps, without any side reaction products. The new phosphite unit and capping agent, bis(1,1,1,3,3,3-hexafluoro-2-propyl)-2-propyl phosphite, is readily activated by N-methylimdazole under very mild condition on a solid support. This operation involves a one pot reaction, which is an advantage over both the phosphite and H- phosphonate approaches. The mechanism of internucleotidic bond formation of the new phosphite method is also discussed. 相似文献
96.
Incorporation of fatty acids by Streptococcus mutans 总被引:1,自引:0,他引:1
Masaru Sato Hironori Tsuchiya Hideki Tani Kohji Yamamoto Ryozo Yamaguchi Hiroshi Nitta Nobutake Kanematsu Isamu Namikawa Nobuhiko Takagi 《FEMS microbiology letters》1991,81(1):117-121
In a series of investigations into the cariogenicity of Streptococcus mutans, we studied the incorporation of exogenous fatty acids with reference to glucosyltransferase secretion and membrane fatty acid changes. When cells were grown with different fatty acids, both saturated and unsaturated fatty acids were readily incorporated into the membrane lipids and were biotransformed and elongated preferentially to the longer 16- and 18-carbon-chain fatty acids. This incorporation and chain-elongation led to significant changes in fatty acids composition. By adding fatty acids to the medium, it was possible to appropriately modify the degree of unsaturation and the relative ratio between specific fatty acids in the membrane lipids of S. mutans. 相似文献
97.
One of the human urinary ribonucleases (RNases) was isolated and purified to homogeneity (SDS-PAGE) by means of a series of column chromatographies. The enzyme, designated RNase 1, is a glycoprotein with a molecular weight of approximately 16,000. Rabbit antibody to the purified RNase 1 reacted with human urine and sera, as well as with the purified RNase 1. The genetic polymorphism of serum RNase 1 was studied by polyacrylamide gel isoelectric focusing (IEF-PAGE) in a pH range of 5-8, followed by immunoblotting with antisera specific for RNase 1. Two common phenotypes, RNASE1 1 and RNASE1 1-2, were easily recognized. The homogeneous phenotype, RNASE1 1, consisted of four major bands with different pI values, and the heterogeneous phenotype, RNASE1 1-2, was presumed to represent a mixture of each of the homogeneous phenotypes 1 and 2; however, the other homogeneous phenotype, RNASE1 2, was not detected in our samples. Family studies are in agreement with an autosomal codominant transmission of the two alleles. Population studies indicate that the frequencies of the RNASE 1 and RNASE1 2 alleles are .988 and .012, respectively. 相似文献
98.
A major glutathione S-transferase form (pI 5.7) in rat testis (MT) purified by S-hexyl-glutathione affinity chromatography, followed by chromatofocusing, showed two polypeptide of pI 6.7 (Yn1) and 6.0 (Yn2), having apparently the same molecular mass of 26 kDa on two-dimensional gel electrophoresis. Rechromatofocusing of the MT preparation after 4 M guanidine hydrochloride treatment revealed two additional protein peaks (pI 6.2 and 5.4). These were identified as the two homodimers consisting of the subunits of MT, Yn1Yn1 and Yn2Yn2, respectively. Furthermore, MT could be reconstituted from Yn1Yn1 and Yn2Yn2. These results indicate that MT is a heterodimer, Yn1Yn2, consisting of subunits with very similar molecular masses but different isoelectric points. The Yn1Yn1 form had glutathione S-transferase activities towards 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene. However, the Yn2Yn2 form had no activity towards any of the substrates examined. N-terminal amino acid sequences of subunits Yn1 and Yn2 revealed differences at two positions in the first 20 residues; the amino acid compositions of these subunits were also similar but not identical, indicating that these two subunits are different in the primary structure. Subunits Yn1 and Yn2 are immunologically related to each other and also to subunits 3 (Yb1) and 4 (Yb2) but they are not identical. These four subunits also showed a high degree of similarity in N-terminal amino acid sequences. Subunits Yn1 and Yn2 seem to belong to the rat GST 3-4 family or class mu. Subunits Yn1 and 4 can make a heterodimer, which is detectable not only in rat testis, but also in the heart, kidney and lung. The Yn1Yn1 form was not detected in the testis, but is present in rat brain [Tsuchida et al. (1987) Eur. J. Biochem. 170, 159-164]. The Yn2Yn2 form seemed to differ from GST 5-5 and may be a new form of rat glutathione S-transferase. 相似文献
99.
Influence of human recombinant interleukin-1 (hrIL-1) on collagen metabolism was investigated with rabbit uterine cervical fibroblasts. Enzyme-linked immunosorbent assays for collagenase and tissue inhibitor of metalloproteinases (TIMP) indicated that hrIL-1 participates in both stimulation of procollagenase production and suppression of TIMP synthesis by uterine cervical cells. IL-1 did not modulate collagen synthesis. In addition, the sensitivity to IL-1 of uterine cervix from ovariectomized rabbits was augmented by estradiol-17 beta treatment. Thus it is proposed that IL-1 accelerates collagenolysis in the cervical tissue and its effect on uterine cervix is hormonally regulated. 相似文献
100.
Developmentally regulated alternative splicing of brain myelin-associated glycoprotein mRNA is lacking in the quaking mouse 总被引:5,自引:0,他引:5
Evidence is presented that expression of the two myelin-associated glycoprotein mRNAs is developmentally regulated in mouse brain. In quaking mouse, the mRNA without a 45-nucleotide exon portion was scarcely expressed throughout development. We conclude that the mechanism of splicing out the 45-nucleotide exon portion is lacking in quaking mouse. 相似文献