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21.
Conformational change of bovine serum albumin by heat treatment 总被引:1,自引:0,他引:1
Kunio Takeda Akira Wada Kazuo Yamamoto Yoshiko Moriyama Koichiro Aoki 《Journal of Protein Chemistry》1989,8(5):653-659
The thermal denaturation of bovine serum albumin (BSA) was studied at pH 2.8 and 7.0 in the range of 2–65°C. The relative proportions of -helix, -structure, and disordered structure in the protein conformation were determined as a function of temperature, by the curve-fitting method of circular dichroism spectra. With the rise of temperature at pH 7.0, the proportion of -helix decreased above 30°C and those of -structure and disordered structure increased in the same temperature range. The structural change was reversible in the temperature range below 45°C. However, the structural change was partially reversible upon cooling to room temperature subsequent to heating at 65°C. On the other hand, the structural change of BSA at pH 2.3 was completely reversible in the temperature range of 2–65°C, probably because the interactions between domains and between subdomains might disappear due to the acid expansion. The secondary structure of disulfide bridges-cleaved BSA remained unchanged during the heat treatment up to 65°C at pH 2.8 and 7.0. 相似文献
22.
The effects of hypophysectomy and gonadotropin replacement on transepithelial movement of 3H-androgen in the rat epididymis were examined by in vivo microperifusion of 3H-testosterone followed by in vivo micropuncture to obtain peritubular and intraluminal fluid. In the caput epididymidis of normal rats, intraluminal 3H-androgen concentrations were approximately 300% of those in the interstitial space. In contrast, proluminal movement of 3H-androgen into rat caput epididymal tubules was significantly decreased 10 days after hypophysectomy. 3H-Testosterone movement across the caput epididymal epithelium was completely returned to normal by supplementation with 24 micrograms/day follicle-stimulating hormone (FSH) or 24 micrograms/day luteinizing hormone (LH). However, neither 0.12 micrograms/day FSH nor 250 micrograms/day prolactin returned proluminal androgen movement to normal. It is speculated that epididymal uptake of peritubular testosterone is mediated by androgen-binding protein, which is known to be secreted by Sertoli cells after stimulation by FSH or testosterone. 相似文献
23.
Primary structure of an N-linked sugar chain derived from glucoamylase of Rhizopus niveus 总被引:2,自引:0,他引:2
K Takegawa N Kawasaki S Iwahara K Yamamoto T Tochikura B Mikami Y Morita 《Biochimica et biophysica acta》1989,990(1):98-100
The primary structure of the N-linked sugar chain of Rhizopus niveus glucoamylase (major component) was investigated. The carbohydrate moiety was released from the polypeptide backbone by Flavobacterium sp. endo-beta-N-acetylglucosaminidase digestion. Studies using the method of exoglycosidase digestion of the fluorescent pyridylamino derivative, gel-permeation chromatography on Bio-Gel P-4 and 400-MHz 1H-NMR spectroscopy revealed that the most abundant structure is (Man)8-GlcNac-ol. 相似文献
24.
The components and variations of glycosaminoglycan (GAG) in the growth of transplantable tumors derived from a spontaneous mouse mammary tumor were investigated. A 45-week-old ddY female mouse, obtained from Shizuoka Laboratory Animal Center, was found to have a bean-sized mass at the third mammary gland of the left side. The tumor mass was surgically excised and used for transplantation in the present study. This mammary tumor was histologically found to be Type B-adenocarcinoma. Transplantable mammary tumors consisted of the fibrous or edematous interstitium contained a large amount of GAG components, which was mainly hyaluronic acid (HA), dermatan sulfate (DS) and chondroitin sulfate A/C (ChS). In the analysis of GAG components, HA content was present in a large amount in logarithmic growth phase of transplanted mammary tumors, but it was markedly decreased in stationary phase. On the other hand, the contents of DS and ChS increased in stationary phase of the tumor growth, and these increases corresponded, histologically, with the propagation of the fibrous interstitial tissues. 相似文献
25.
Spontaneous malignant fibrous histiocytoma (MFH) of the chest wall was found in a 10-year-old male Japanese white rabbit. Histologically, the MFH consisted mainly of areas of storiform, pleomorphic and myxoid patterns. Positive reactions for acid phosphatase (Ac-P), non-specific esterase (N-SE) and beta-glucuronidase (beta-GL) were demonstrated in fibroblast-like, histiocyte-like and giant cells. Moreover, a strongly positive fibronectin (FN) reaction was observed mainly in histiocyte-like and giant cells. In electron microscopy, tumor cells were composed morphologically of various types of cells such as fibroblast-like, histiocyte-like, undifferentiated and giant cells. This case was quite similar to those reported in man or other animals. 相似文献
26.
N Yamamoto M M Rahman M Fukushima K Maeno Y Nishiyama 《Biochemical and biophysical research communications》1989,158(1):189-194
Cyclopentenone prostaglandin (PG), delta7-PGA1 was found to induce several polypeptides in human embryonic fibroblast (HEF) cells which were noticed to be dose-related and appeared after 1 h of treatment with a peak at around 5 h and gradual disappearance after 12 h. PG-induced proteins were almost identical in terms of molecular weights with those induced by heat-shock at 42 degrees C. Regarding the mechanism of inhibition of herpes simplex virus (HSV) replication by PG in cell culture, dot blot hybridization has revealed that the level of immediate early (IE) mRNA of the virus was reduced after PG treatment with time dependence. And this delayed inhibitory effect of delta7-PGA1 on HSV was shown to be associated with the production and accumulation of the induced polypeptides. 相似文献
27.
28.
To determine the relative contribution of mate access and environmental cues in stimulating egg-laying and plasma luteinizing hormone (LH) secretion in cockatiels (Nymphicus hollandicus), and of mate access on nest-inspection and bowl-formation, mated pairs were permitted different degrees of mate access (full contact, auditory plus visual contact, auditory contact only, or no contact) and sequentially exposed to three environmental conditions (8L:16D without nest-box access for 6 weeks; 15L:9D without nest-box access for 3 weeks; 15L:9D with nest-box access for 3 weeks). The results indicate that a high degree of mate access is essential for the performance of nesting behaviors, since birds allowed no mate access or only auditory mate access were significantly less likely to inspect the nest or form a nest-bowl. Furthermore, pairs permitted no contact, auditory contact only, or auditory and visual contact delayed nest-inspection and bowl-formation and were significantly less likely to lay eggs than pairs with total mate contact. LH levels were significantly elevated only in photostimulated females of pairs of permitted full mate and nest-box access. These results suggest that maximal sexual activity in cockatiels requires an array of behavioral and environmental cues and that a linear relationship exists between extent of social cues and sexual activity. 相似文献
29.
The mesencephalic reticular formation (MRF) neurons are regarded as contributing to the activation of the celebral cortex. In this paper, the statistical features of single neuronal activities in MRF of cat during dream sleep are investigated; the neuronal spike train exhibits 1/f fluctuations. Counting statistics is applied to the neuronal spike train giving rise to a variance/mean curve which follows at
-law. For an interpretation of these findings, the clustering Poisson process is applied which not only gives rise to at
-law but also suggests a generation mechanism. The MRF neuronal activities are closely fitted by the clustering Poisson process and the underlying statistical parameters can be estimated. These findings strongly suggest that neuronal activities can be interpreted as superposition of randomly occuring clusters ( = bursts of spikes). 相似文献
30.
E Yabuuchi I Yano H Oyaizu Y Hashimoto T Ezaki H Yamamoto 《Microbiology and immunology》1990,34(2):99-119