共查询到20条相似文献,搜索用时 46 毫秒
1.
V. Erspamer P. Melchiorri T. Nakajima T. Yasuhara R. Endean 《Cellular and molecular life sciences : CMLS》1979,35(9):1132-1133
Summary Methanol extracts of the skin of the Australian amphibianCrinia georgiana contain large amounts of crinia-angiotensin II, a new angiotensin II-like peptide. This differs sharply from the conventional octapeptide angiotensins II in having attached the tripeptide Ala-Pro-Gly- to the N-terminus, and having an Ile residue substituted for the Val residue at position 6 from the C-terminus. Small amounts of angiotensin-like peptides have been traced, by radioimmunoassay, in skin extracts of some otherCrinia species.Supported by grants from the Consiglio Nazionale delle Ricerche, Italy, and from the Ministry of Education, Japan. 相似文献
2.
A. Anastasi P. Montecucchi V. Erspamer J. Visser 《Cellular and molecular life sciences : CMLS》1977,33(7):857-858
Summary Methanol extracts of the skin of the African amphibian Kassina senegalensis contain a dodecapeptide, kassinin, belonging to the family of tachykinins or physalaemin-like peptides. Kassinin, like all other natural tachykinins, possesses the characteristic C-terminal tripeptide Gly-Leu-Met-NH2 and a phenylalanine residue in position 5 from the C-terminus. However, the amino acid sequence in the N-moiety of the molecule differs sharply from that of the other tachykinins.Supported in part by grants from the Consiglio Nazionale delle Ricerche, Roma. 相似文献
3.
T. Nakajima T. Yasuhara G. Falconieri Erspamer J. Visser 《Cellular and molecular life sciences : CMLS》1979,35(9):1133-1133
Summary Methanol extracts of the skin of the South African amphibians belonging to the genusHeleophryne (H. purcelli purcelli, H. purcelli depressa, H. purcelli orientalis, H. natalensis) contain large amounts (20–500 g/g fresh tissue) of Hyp3-bradykinin.Supported by grants from the Consiglio Nazionale delle Ricerche, Italy, and from the Ministry of Education, Japan. 相似文献
4.
Dewaxed leaf surface extracts of 12 plants from Hokkaido, prepared by dipping fresh leaves in chloroform for 3 min, were used in a choice leaf-disk bioassay against larvae of the tobacco cutwormSpodoptera litura. Activity was found only in the extract ofSenecio cannabifolius, a very successful weed in Hokkaido. Individual fractions of the extract, however, were not active. Incorporation of the individual fractions of the surface extracts as well as fractions of the methanolic extracts of the leaf residue into an artificial diet fed to neonateS. litura led to the isolation of ethyl (1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, the major surface compound, as the active principle. This compound was also present in the methanolic extract of the leaf residue together with methyl (1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, which had the same growth inhibitory effect on the larvae. The presence of these compounds in the foliar surface and tissue suggests a defensive role against herbivores. 相似文献
5.
A. Anastasi P. Montecucchi F. Angelucci V. Erspamer R. Endean 《Cellular and molecular life sciences : CMLS》1977,33(10):1289-1289
Summary The second bombesin-like peptide occurring in methanol extracts of the skin of the Australian frog Litoria aurea was isolated in a pure form and identified as Glu (OMe)2-litorin.Supported in part by grants from the Consiglio Nazionale delle Ricerche, Roma. 相似文献
6.
The ratio between large and small carboxy-terminal forms of cholecystokinin in brain extracts from man, pig, dog, rat, chicken, frog and trout was determined by two sequence-specific radioimmunoassays. It was found that the relative amounts of large forms of cholecystokinin; are higher in mammalian brain than in brains of lower species. 相似文献
7.
P. Montecucchi G. Falconieri Erspamer J. Visser 《Cellular and molecular life sciences : CMLS》1977,33(9):1138-1139
Summary The skin of the African frog, Hylambates maculatus, contains large amounts of a caerulein-like peptide, which has been identified as Asn2, Leu5-caerulein. The cholecystokinetic activity of Hylambates-caerulein is very similar to that of caerulein.Supported in part by grants from the Consiglio Nazionale delle Ricerche, Roma, Italy. 相似文献
8.
A combination of differential centrifugation and isopycnic sucrose density gradient centrifugation of extracts from spinach leaves (Spinacia oleracea L.) shows that about 20% of the O-Acetylserine sulfhydrylase are associated with chloroplasts. No appreciable amounts of O-Acetylserine sulfhydrylase band with mitochondrial and peroxisomal marker enzymes. 相似文献
9.
It was found that cell-free extracts of Saccharomyces cerevisiae contain thiaminase II which hydrolyzes thiamine and thiamine analogs. The possible involvement of this enzyme and thiamine-synthesizing enzymes in thiamine production from thiamine antagonists is discussed. 相似文献
10.
Isolation and amino acid compositions of geographutoxin I and II from the marine snail Conus geographus 总被引:3,自引:0,他引:3
The peptide toxins having inhibitory effects on the contractile response of the mouse diaphragm to direct stimulation, geographutoxin I and II, have been isolated from Conus geographus, and their amino acid compositions have been determined. 相似文献
11.
G K Khuller 《Experientia》1976,32(11):1371-1372
The phospholipid of N. asteroides has been investigated. It was found to contain phosphatidyl ethanolamine, cardiolipin, phosphatidyl inositol and a family of mannophosphoinositides. Dimannophosphoinositides with 3 and 4 moles of fatty acid per phosphate residue represented the major glycophospholipids besides small amounts of other more glycosylated mannophosphoinositides. 相似文献
12.
Chromatography on phosphocellulose revealed the existence of two well-separable forms of skeletal muscle AMP-deaminase in the tissue extracts of 11- and 16-week-old human fetuses. One of these forms elutes from the column at the same salt concentration as the muscle isozyme found in the skeletal muscle extract from adult man, and seems to have similar kinetic properties. The second form, which was found only in vestigial amounts in adult human tissue extract, represents different kinetic properties and seems to be a form characteristic for the fetal period of ontogenesis. 相似文献
13.
张永库 《世界科技研究与发展》2009,31(6):1053-1054
为了解决聚类分析中聚类数的确定问题,在SOFM神经网络的基础上,从聚类准则出发,通过试验对聚类准则的曲线特征进行了详细的分析和论证,设计出一种结构自适应的聚类神经网络,该网络能自动确定最佳的聚类数,并提出了一种减少计算量的改进算法。 相似文献
14.
P. Fusi M. Villa N. Burlini P. Tortora A. Guerritore 《Cellular and molecular life sciences : CMLS》1991,47(10):1057-1060
Proteolytic activities from the extremely thermoacidophilic archaebacteriumSulfolobus solfataricus were detected with the aid of synthetic substrates in a cell extract fractionated by gel filtration. Two aminopeptidases (aminopeptidase I and II), three endopeptidases (proteinase I, II and III) and one carboxypeptidase could be identified. Experiments carried out with protease inhibitors led to the identification of the exopeptidases as metalloproteases. Proteinases I and II behaved as chymotrypsin-like serine proteases, and proteinase III as a cysteine protease with a trypsin-like specificity. Molecular weight values assessed with the aid of marker proteins were as follows: aminopeptidase I, >450 kDa; aminopeptidase II, 170 kDa; carboxypeptidase, 160 kDa; proteinase I, 115 kDa; proteinase II, 32 kDa; proteinase III, 27 kDa. On incubation for 15 min they retained most of their activity up to a temperature of 90°C, with the sole exception of proteinase II, which was rapidly inactivated at 60°C. Protease content was also determined in crude extracts from cells grown in a mineral medium both to the stationary and to the exponential phase, with glucose or with yeast extract as carbon sources. No dramatic change was detected depending on the growth phase; however, carboxypeptidase level was three- to four-fold higher when yeast extract was present in the medium instead of glucose; this might suggest an involvement of this enzyme in the digestion of extracellularly available peptides. 相似文献
15.
Melles E Jörnvall H Tryggvason S Danielsson KG Ekberg K Tryggvason K Wahren J Bergman T 《Cellular and molecular life sciences : CMLS》2004,61(23):2979-2982
Degradation of proinsulin C-peptide in mouse kidney and human placenta extracts was studied using reverse-phase high-performance liquid chromatography and nano-electrospray mass spectrometry. In total, 15 proteolytic cleavage sites were identified in human and mouse C-peptides. Early sites included the peptide bonds N-terminal of Val/Leu10, Leu12, Leu21, Leu24 and Leu26 in different combinations for the two tissues and two peptides. Notably, these cleavages were N-terminal of a hydrophobic residue, and all but one N-terminal of Leu. A late degradation product of the human peptide detected in the kidney extract was the C-terminal hexapeptide, containing just one residue more than the biologically active C-terminal pentapeptide of C-peptide. We conclude that the degradation of C-peptide in kidney and placenta follows similar patterns, dominated by endopeptidase cleavages N-terminal of Leu. 相似文献
16.
Repeated oral administration of cannabis extract as well as synthetic delta9-tetrahydrocannabinol to male rats produced significant changes in excretion of androgenic steroids and their metabolites as detectable in blood and urine. Cannabis extracts were found to be significantly more active than the mixtures containing same amounts of synthetic cannabinoids. 相似文献
17.
H. Fankhauser Chr Brunold K. H. Erismann 《Cellular and molecular life sciences : CMLS》1976,32(12):1494-1497
Summary A combination of differential centrifugation and isopycnic sucrose density gradient centrifugation of extracts from spinach leaves (Spinacia oleracea L.) shows that about 20% of the O-Acetylserine sulfhydrylase are associated with chloroplasts. No appreciable amounts of O-Acetylserine sulfhydrylase band with mitochondrial and peroxisomal marker enzymes.This work was supported in part by the Swiss National Foundation (SNF), grant No. 3.610-0.75. 相似文献
18.
Th. F. Spande J. W. Daly D. J. Hart Y-M. Tsai T. L. Macdonald 《Cellular and molecular life sciences : CMLS》1981,37(12):1242-1245
Summary The structure 3-butyl-5-propylindolizidine (2), tentatively assigned to a minor alkaloid in skin extracts from a number of poison frogs of the Neotropical genusDendrobates, has been confirmed and its stereochemistry determined as 5E, 9E (2d) by comparison on GC and GC-MS with the four synthetic diastereomers2a-2d. 相似文献
19.
D. Robinette S. Wada T. Arroll M. G. Levy W. L. Miller E. J. Noga 《Cellular and molecular life sciences : CMLS》1998,54(5):467-475
Three antibacterial proteins were isolated from acid extracts of channel catfish (Ictalurus punctatus) skin by cation exchange chromatography and reverse-phase high-pressure liquid chromatography. The molecular masses of the
proteins were 15.5, 15.5 and 30 kD as determined by SDS-polyacrylamide gel electrophoresis. Mass spectrometry, amino acid
composition and amino acid sequence data suggest that the most abundant protein is closely related to histone H2B. The H2B-like
protein was inhibitory to Aeromonas hydrophila and Saprolegnia spp., which are important bacterial and fungal pathogens of fish. These findings suggest that histones may be important defensive
molecules in fish.
Received 22 December 1997; received after revision 5 March 1998; accepted 5 March 1998 相似文献
20.
G. K. Khuller 《Cellular and molecular life sciences : CMLS》1976,32(11):1371-1372
Summary The phospholipid ofN. asteroides has been investigated. It was found to contain phosphatidyl ethanolamine, cardiolipin, phosphatidyl inositol and a family of mannophosphoinositides. Dimannophosphoinositides with 3 and 4 moles of fatty acid per phosphate residue represented the major glycophospholipids besides small amounts of other more glycosylated mannophosphoinositides. 相似文献