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Synthesis and in vitro bioactivity of C-terminal deleted analogs of human growth hormone-releasing factor 总被引:4,自引:0,他引:4
N Ling A Baird W B Wehrenberg N Ueno T Munegumi P Brazeau 《Biochemical and biophysical research communications》1984,123(2):854-861
A series of C-terminal deleted analogs of human growth hormone-releasing factor (hGRF) with either an amidated or a free carboxylic acid C-terminus were synthesized by solid phase methodology. Their capacity to release growth hormone was tested on rat anterior pituitary cells in monolayer culture. A gradual decrease of bioactivity down to 23% relative to hGRF was noted when the C-terminal amino acids were deleted to hGRF (1-34)OH. Further deletions, however, did not decrease the bioactivity because the potencies of the fragments, hGRF(1-31)NH2, (1-30)NH2 and (1-29)NH2 remained at about 50% of that of hGRF. Continual deletion of residues to hGRF(1-23)NH2, (1-22)NH2 and (1-21)NH2 still yielded bioactive fragments with full intrinsic activity despite very low potency. Only with the deletion down to hGRF(1-19)NH2 did the bioactivity completely disappear. Thus, together with the data published in a previous paper (1), the minimal biologically active core of hGRF with full intrinsic activity comprises the fragment (3-21). 相似文献
24.
Tuneyoshi Omori Yuji Inaba Tomiaki Morimoto Yoshio Tanaka Hiroshi Kurogi Minoru Matumoto 《Microbiology and immunology》1967,11(2):133-142
Five strains of bovine diarrhea virus were isolated from Japanese cattle using bovine tissue cultures. These are the first isolations of this virus from Japanese cattle to be reported. Of importance is the finding that the new isolates, which are non-cytopathogenic, induce an exaltation of Newcastle disease virus in bovine testicular cell culture. This finding has provided a laboratory tool whereby the assay of the virus and its neutralizing antibody can readily be performed. 相似文献
25.
Hiroshi Monoi 《生物化学与生物物理学报:生物膜》1982,693(1):159-164
An electrostatic calculation suggests that when an ion is bound near the mouth of a channel penetrating a low-dielectric membrane, a counter ion may form an ion pair with this ion. The tendency towards ion-pair formation is remarkably enhanced at channel mouths by forces (image forces) arising from the charges induced on the boundaries between different dielectrics. The binding constant for the formation of ion-pairs of monovalent ions is estimated under the assumption that local interactions between the counter ion and the channel wall are negligibly small. It is of the order of 1–10 molal?1 or more for the binding of a Cl? (F?) counter ion to an () ion if appropriate conditions are fulfilled. The binding constant depends on the position of the binding site, the dimensions and geometries of the channel and channel mouth, and the state of ion loading of the channel, as well as the ionic species. The present results also indicate that when cation (anion) channels have anionic (cationic) groups as integrant parts of their channel walls, interactions between these charged groups and permeant ions are markedly enhanced by the image forces. 相似文献
26.
Haruhide Kawabe Hiroshi Naganawa Shinichi Kondo Hamao Umezawa Susumu Mitsuhashi 《Microbiology and immunology》1978,22(9):515-521
A clinical isolate of Staphylococcus aureus resistant to gentamicin, kanamycin and 3′,4′-dideoxykanamycin B contained two enzymes capable of inactivating gentamicin, i.e., an aminoglycoside 2″-phosphotransferase and aminoglycoside acetyltransferase. 相似文献
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Summary An activated carbon column was utilized for the synthesis of disaccharides by use of a reversed hydrolysis activity of an immobilized -galactosidase column in order to shift the equilibrium to the direction of condensation. The yields of lactulose and allo-lactulose from galactose and fructose, and N-acetyl lactosamine and N-acetyl allolactosamine from galactose and N-acetyl glucosamine, were 11.3% and 10.0%, respectively. 相似文献
29.
Summary
E.
coli cells harbouring plasmid pBR322 which confers ampicillin resistance were immobilized on cotton cloth. The resulting film was used as an inoculum in daily repeated batch culture in ampicillin-free medium. During two months, the film was able to produce cultures which, at the late log phase, showed little sensitivity to 10 mg/ml ampicillin. Thus such a bacterial film can effectively be used as an inoculum for the production of recombinant DNA products by means of pBR322 or its derivatives in the absence of ampicillin. 相似文献
30.
Suncus murinus: a new experimental model in emesis research 总被引:2,自引:0,他引:2
Effects of various emetic and antiemetic drugs were studied using Suncus murinus for its potential use as an experimental model in emetic research. Subcutaneous injection of nicotine bitartrate (10-15 mg/kg), veratrine sulfate (0.5-1.0 mg/kg), emetine dihydrochloride (40-80 mg/kg) and oral administration of copper sulfate (20-100 mg/kg) caused dose-dependent emesis in suncus. The ED50 of nicotine, veratrine, emetine and copper sulfate were 7.9, 0.4, 47.6 and 21.4 mg/kg, respectively. However, subcutaneously injected apomorphine hydrochloride (0.1-100 mg/kg), digitoxin (0.5-1.0 mg/kg) and orally administered emetine dihydrochloride (10-80 mg/kg) did not induce the vomiting. Chlorpromazine and promethazine decreased the emetic effect of nicotine, veratrine and copper sulfate, but scopolamine hydrobromide was not effective. These results indicate that the Suncus murinus is sensitive to various emetic and antiemetic drugs and can be used as a new experimental animal model for the emesis. Emetic behavior of suncus was discussed in comparison with other animals. 相似文献