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51.
Craig J. Coates Catherine L. Turney Marianne Frommer David A. O'Brochta W. D. Warren Peter W. Atkinson 《Molecular & general genetics : MGG》1995,249(2):246-252
Plasmid-based excision assays performed in embryos of two non-drosophilid species using the mariner transposable element from Drosophila mauritiana resulted in empty excision sites identical to those observed after the excision of mariner from D. mauritiana chromosomes. In the presence of the autonomous mariner element Mos1, excision products were recovered from D. melanogaster, D. mauritiana and the blowfly Lucilia cuprina. When a hsp82 heat shock promoter-Mos1 construct was used to supply mariner transposase, excision products were also recovered from the Queensland fruitfly Bactrocera tryoni. Analysis of DNA sequences at empty excision sites led us to hypothesise that the mariner excision/repair process involves the formation of a heteroduplex at the excision breakpoint. The success of these assays suggests that they will provide a valuable tool for assessing the ability of mariner and mariner-like elements to function in non-drosophilid insects and for investigating the basic mechanisms of mariner excision and repair. 相似文献
52.
During the production by mammalian cells of recombinant factor VIII from which the B domain was deleted (rFVIII), proteolytic
cleavages in the C-terminal part of the heavy chain were observed (Kjalke et al., 1995). By radioactive pulse labelling it
was investigated whether the cleavages took place inside the cells during protein synthesis or after release in the medium.
The rFVIII-producing CHO (Chinese hamster ovary) cells were cultured in the presence of 35S-methionine and then the cell lysate and the conditioned media were immunoprecipitated and analyzed by electrophoresis. By
pulse labelling and chasing for various time periods, it was shown that the cleavages only took place after secretion of the
protein from the cells. Adding cell lysate to uncleaved rFVIII caused cleavage of the heavy chain, as seen by loss of binding
to a monoclonal antibody specific for intact rFVIII, indicating that the cleavage was performed by proteinase(s) released
from the lysed cells. By incubating intact rFVIII with the multicatalytic proteinase (proteasome) present in cytoplasm and
nucleus of eukaryotic cells, loss of binding to the monoclonal antibody was observed. This indicates that the multicatalytic
proteinase, released from lysed rFVIII producing cells, could be responsible for the cleavage of rFVIII. Among several protease
inhibitors tested, only bacitracin was found to diminish the extent of cleavage. Phosphatidylserine also protected rFVIII
against cleavage, probably by binding to rFVIII.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
53.
The 5-HT (serotonin) distribution in the nervous system of the macrodasyoid gastrotrich Turbanella cornuta was studied using immunocytochemical methods. Positive immunoreaction was found in two pairs of neurons. The neurons of one pair had processes which extended peripherally to the surface of the body. Central processes of both pairs entered the brain commissure and proceeded into the longitudinal cords. Unlike other acoelomate worms studied so far, the Platyhelminthes and the Nematoda, in this gastrotrich no 5-HT positive perikarya or processes were present in the pharynx innervation, and no positive neurons sent processes directly to the nerve cords 相似文献
54.
Seven New Mutations in hMSH2, an HNPCC Gene, Identified by Denaturing Gradient-Gel Electrophoresis 总被引:21,自引:3,他引:18
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Juul Wijnen Hans Vasen P. Meera Khan Fred H. Menko Heleen van der Klift Claus van Leeuwen Marianne van den Broek Inge van Leeuwen-Cornelisse Fokko Nagengast Anne Meijers-Heijboer Dick Lindhout Gerrit Griffioen Annemieke Cats Jan Kleibeuker Liliana Varesco Lucio Bertario Marie Luise Bisgaard Jan Mohr Riccardo Fodde 《American journal of human genetics》1995,56(5):1060-1066
Hereditary nonpolyposis colorectal cancer (HNPCC) is a relatively common autosomal dominant cancer-susceptibility condition. The recent isolation of the DNA mismatch repair genes (hMSH2, hMLH1, hPMS1, and hPMS2) responsible for HNPCC has allowed the search for germ-line mutations in affected individuals. In this study we used denaturing gradient-gel electrophoresis to screen for mutations in the hMSH2 gene. Analysis of all the 16 exons of hMSH2, in 34 unrelated HNPCC kindreds, has revealed seven novel pathogenic germ-line mutations resulting in stop codons either directly or through frameshifts. Additionally, nucleotide substitutions giving rise to one missense, two silent, and one useful polymorphism have been identified. The proportion of families in which hMSH2 mutations were found is 21%. Although the spectrum of mutations spread at the hMSH2 gene among HNPCC patients appears extremely heterogeneous, we were not able to establish any correlation between the site of the individual mutations and the corresponding tumor spectrum. Our results indicate that, given the genomic size and organization of the hMSH2 gene and the heterogeneity of its mutation spectrum, a rapid and efficient mutation detection procedure is necessary for routine molecular diagnosis and presymptomatic detection of the disease in a clinical setup. 相似文献
55.
Marianne Borloo Koen Augustyns Alexander Belyaev Ingrid de Meester Anne-Marie Lambeir Filip Goossens Willy Bollaert Padinchare Rajan Simon Scharpé Achiel Haemers 《Letters in Peptide Science》1995,2(3-4):198-202
Summary A series of azaproline dipeptides with various N-substituents were synthesized as possible active-site-directed inhibitors of two proline-specific serine proteases, dipeptidyl peptidase IV and prolyl oligopeptidase. Compounds with semicarbazide, carbazate, acylhydrazine and sulphonylhydrazine structures were tested. Some compounds show moderate activity, i.e., in the millimolar range. 相似文献
56.
André W. Schram Marianne Dreissen Johan Bastiaannet Wilma E. Donker-Koopman Elisabeth M. Brouwer-Kelder Gabriele Weitz John A. Barranger Konrad Sandhoff Joseph M. Tager 《Bioscience reports》1984,4(12):1051-1057
The immunoblotting technique was used to identify sphingomyeJinase protein in samples of tissue and urine after subjection to poIyacrylamide-gel etectrophoresis in the presence of sodium dodecyl sulphate. In a sphingomyelinase preparation purified from control urine a prominent band was seen with an Mr of 28 000 Da. Glycoprotein fractions from urine and placenta, a membrane extract from spleen, and a partially purified sphingomyelinase preparation from placenta contained the 28 000-Da band plus additional, higher-Mr bands. The 28 000-Da band was detectable in urine from a patient with Niemann-Pick disease type C, but not in urine from patients with Niemann-Pick disease types A and B. It is concluded t h a t sphingomyeJinase is composed of at least one polypeptide with an Mr of 28 000 Da and that this polypeptide is deficient in the urine of patients with Niemann-Pick disease types A and B. 相似文献
57.
Summary Experiments were performed to investigate growth, ethanol and glycerol production by wild-type strains (RHO) and respiratory-deficient (rho) mutants of Saccharomyces cerevisiae. Furthermore protoplasts were fused in order to enhance the fermentation capacity of a flocculent strain. At high substrate conditions, 150 g/l of saccharose, there is no difference in cell growth. However, at a glucose concentration of 10–20 g/l the mutants grow much slower. After 3 days of incubation at 28° C in a complete medium the viability of the two strains is the same. In minimal medium on the other hand the number of viable cells of the mutant is 100-fold reduced. All mutants tested showed a higher specific activity of alcohol dehydrogenase (ADH I) and an enhanced production of glycerol compared with the wild-type strain. By protoplast fusion a modified flocculent strain was obtained with higher specific activity of ADH I and a reduced biosynthesis of glycerol. However, the yields of ethanol (75–78%) are about the same for the wild-type strain and the rho mutants under aerobic conditions in absence of catabolite repression. 相似文献
58.
Marianne Philipp 《Ecography》1978,1(1):46-53
The vegetation of a snow bed has been described by a pin-point method and a modified Raunkiær frequency analysis. The thawing of the snow has been followed and some soil properties have been investigated. It is concluded that the composition of the vegetation in the snow bed is influenced mainly by the duration of the growth period, but locally the density and the species composition are determined by the downward flow of the melt water. 相似文献
59.
G Cecchini M Perl J Lipsick T P Singer E B Kearney 《The Journal of biological chemistry》1979,254(15):7295-7301
Riboflavine uptake and membrane-associated riboflavin-binding activity has been investigated in Bacillus subtilis. Riboflavin uptake proceeds via a system whose general properties are indicative of a carrier-mediated process: it is inhibited by substrate analogues, exhibits saturation kinetics, and is temperature-dependent. The organism concentrates riboflavin primarily as the phosphorylated cofactors FMN and FAD. Energy is required for uptake but whether the energy demand is required for both uptake and phosphorylation or only for the phosphorylation step is not known. Membrane-associated binding activity for riboflavin has also been demonstrated in membrane vesicles prepared from B. subtilis, and the binding component can be "solubilized" with Triton X-100. Evidence supporting the function of the binding component in riboflavin uptake by the intact cells includes the following. (i) Riboflavin analogues inhibit binding and uptake to nearly the same extent and with similar specificity of action. (ii) The KD for riboflavin-binding and the Km for uptake are in the same range. Similarly the Ki determined for the inhibitory analogue 5-deazariboflavin in the uptake assay and the KD for its interaction with the riboflavin-binding component of membrane vesicles are in the same range. (iii) Uptake in cells and binding in vesicles vary in the same direction with differences in growth conditions. 相似文献
60.
James V. Neel Robert J. Tanis Ernest C. Migliazza Richard S. Spielman Francisco Salzano William J. Oliver Marianne Morrow Sally Bachofer 《Human genetics》1977,36(1):81-107
Summary Blood samples from 509 Macushi and 623 Wapishana Amerindians of Northern Brazil and Southern Guyana have been analyzed with reference to the occurrence of rare variants and genetic polymorphisms of the following 25 systems: (i) Erythrocyte enzymes: acid phosphatase-1, adenosine deaminase, adenylate kinase-k, carbonic anhydrase-1, carbonic anhydrase-2, esterase A1,2,3, esterase D, galactose-1-phosphate uridyltransferase, isocitrate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, nucleoside phosphorylase, peptidase A, peptidase B, phosphoglucomutase 1, phosphoglucomutase 2, phosphogluconate dehydrogenase, phosphohexoseisomerase, triosephosphate isomerase and (ii) Serum proteins: albumin, ceruloplasmin, haptoglobin, hemoglobin A, hemoglobin A2 and transferrin. Fifteen different rare variants were detected, involving 11 of these systems. In addition, a previously undescribed variant of ESA1,2,3 which achieves polymorphic proportions in both these tribes is described. Excluding this variant, the frequency of rare variants is 1.1/1000 in 12510 determinations in the Macushi and 4.7/1000 in 15 396 determinations in the Wapishana. The ESA1,2,3, polymorphism was not observed in 382 Makiritare, 232 Yanomama, 146 Piaroa, 404 Cayapo, 190 Kraho and 112 Moro. Irregularities in the intratribal distribution of this polymorphism in the Macushi and Wapishana render a decision as to the tribe of origin impossible at present. Gene frequencies are also given for previosly described polymorphisms of 5 systems: haptoglobin, phosphoglucomutase 1, erythrocyte acid phosphatase, esterase D, and galactose-1-phosphate-uridyl-transferase.Research supported by the National Science Foundation and the Energy Research and Development Administration. 相似文献