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1.
Novel inhibition of proteoglycan synthesis and exocytosis by diethylcarbamazine in the Swarm rat chondrocyte 总被引:2,自引:0,他引:2
R L Stevens W G Parsons K F Austen A Hein J P Caulfield 《The Journal of biological chemistry》1985,260(9):5777-5786
Pretreatment of cultured chondrosarcoma chondrocytes at 37 degrees C for 15 min with 15 mM diethylcarbamazine (DEC) followed by a 60-min pulse with [35S] sulfate in the presence of DEC resulted in an approximate 40% inhibition of synthesis and a 75% inhibition of secretion of 35S-proteoglycan. The inhibition was dose-related and was not due to a decrease in protein synthesis. Chondrocytes exposed for 75 min to 15 mM DEC, washed, incubated for 17 h in DEC-free medium, and then pulsed with [35S]sulfate showed no inhibition in the rate of synthesis of proteoglycan or in the per cent of radiolabeled proteoglycans exocytosed into the culture medium, indicating full reversibility of the inhibitory effect. When chondrocytes were incubated for 75 min with both 1 mM beta-D-xyloside and 15 mM DEC, secretion of beta-D-xyloside-bound 35S-glycosaminoglycan was inhibited by more than 70% despite an approximate 3-fold increase in intracellular 35S-macromolecules, as compared to cells exposed to beta-D-xyloside alone. Upon removal of DEC, the block in the secretion of beta-D-xyloside-bound 35S-glycosaminoglycans was reversed, although there was a 15-30-min lag in the initiation of exocytosis. Light and electron microscopic examination of chondrocytes after 75 min of incubation with 15 mM DEC revealed large vacuoles, a distended Golgi apparatus, and a distended endoplasmic reticulum which contained electron dense material. Upon removal of DEC, the vacuoles disappeared and distended organelles returned to their normal appearance between 15 and 30 min, coincident with the start of exocytosis of 35S-proteoglycan and beta-D-xyloside-bound 35S-glycosaminoglycan. These biochemical and morphological studies indicate that DEC treatment of chondrosarcoma chondrocytes alters the transport of molecules from the endoplasmic reticulum to the Golgi and the transport of molecules from the Golgi to the cell surface. 相似文献
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J Hein 《Mathematical biosciences》1990,98(2):185-200
The parsimony principle states that a history of a set of sequences that minimizes the amount of evolution is a good approximation to the real evolutionary history of the sequences. This principle is applied to the reconstruction of the evolution of homologous sequences where recombinations or horizontal transfer can occur. First it is demonstrated that the appropriate structure to represent the evolution of sequences with recombinations is a family of trees each describing the evolution of a segment of the sequence. Two trees for neighboring segments will differ by exactly the transfer of a subtree within the whole tree. This leads to a metric between trees based on the smallest number of such operations needed to convert one tree into the other. An algorithm is presented that calculates this metric. This metric is used to formulate a dynamic programming algorithm that finds the most parsimonious history that fits a given set of sequences. The algorithm is potentially very practical, since many groups of sequences defy analysis by methods that ignore recombinations. These methods give ambiguous or contradictory results because the sequence history cannot be described by one phylogeny, but only a family of phylogenies that each describe the history of a segment of the sequences. The generalization of the algorithm to reconstruct gene conversions and the possibility for heuristic versions of the algorithm for larger data sets are discussed. 相似文献
4.
Crossovers in two German cystic fibrosis families determine probe order for MET, 7C22 and XV-2c/CS.7 总被引:6,自引:0,他引:6
W. Berger J. Hein J. Gedschold I. Bauer A. Speer M. Farrall R. Williamson C. Coutelle 《Human genetics》1987,77(2):197-199
Summary We have followed the segregation of the probes pJ3.11, 7C22, pB79a, and MET through cystic fibrosis families in the German Democratic Republic with two affected sibs. Two families with a crossover between MET and the CF phenotype were detected. In one of these families recombination was also observed between the DNA probe 7C22 and CF, and between the markers XV-2c and CF, which suggests that XV-2c, MET and 7C22 are all on the same side of CF. The other MET recombinant family is informative with XV-2c and does not recombine, which excludes the genetic order XC-2c-MET-CF if multiple recombinant events are disregarded. These two families together demonstrate that recombinations may occur in a very small genetic interval, which has important implications for prenatal diagnosis based on data from linked markers. 相似文献
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Class I major histocompatibility complex cDNA clones from sheep thymus: alternative splicing could make a long cytoplasmic tail 总被引:4,自引:4,他引:0
To investigate the class I major histocompatibility complex (MHC) genes expressed in the young sheep thymus, a cDNA library was screened with a human HLA-B7 cDNA probe under conditions of relaxed stringency. Thirteen clones were isolated and found by partial sequences to fall into five classes, requiring the expression of at least three loci. One sequence was found six times, almost half of the total, and may thus represent the major message expressed in the young sheep thymus. One of the clones was found to have failed to excise the intron between cytoplasmic exons 7 and 8, leading to the predicted synthesis of a cytoplasmic domain 23 amino acids longer than the other sheep sequences, and 15 amino acids longer than any cytoplasmic domain previously described. The sequences of all the clones were found to be most similar to bovine, and least similar to mouse class I MHC sequences.The nucleotide sequence data reported in this paper have been sunmitted to the GenBank nucleotide sequence database and have been assigned the accession numbers M 34672-6. 相似文献
7.
The nucleotide (nt) and deduced amino acid (aa) sequences were determined for polymorphic arylamine N-acetyl-transferase (NAT2) and its gene, NAT2, from homozygous rapid and slow acetylator congenic Syrian hamsters. The slow acetylator (NAT2s) allele contained three point mutations which differed from the rapid acetylator allele (NAT2r); two mutations were silent, and the third mutation resulted in a premature stop codon. The NAT2r allele contained a truncated open reading frame of 726 nt encoding a 242-aa protein, which is 48-aa shorter than NAT2r. 相似文献
8.
Dario Grossberger Anne Marcuz Annette Fichtel Lisbeth Dudler Wayne R. Hein 《Immunogenetics》1993,37(3):222-226
The nucleotide sequences reported in this paper have been submitted to the GenBank database and have been assigned the accession numbers M94181-M94183. 相似文献
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The history of diatom research in The Netherlands and Flanders is summarized in this report. A. van Leeuwenhoek observed diatoms as early as 1702. The first inventories were made in The Netherlands by R. B. van den Bosch (1846) and in Flanders by J.-J. Kickx (1867). Diatoms were already used in geological research in the second half of the nineteenth century. The Synopsis by H. van Heurck (1880–1885) enabled many twentieth century workers to do applied research for geological and ecological purposes. 相似文献