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91.
Intraluminal proteolytic activation plays an important role in replication of type 1 reovirus in the intestines of neonatal mice. 总被引:17,自引:15,他引:2
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D M Bass D Bodkin R Dambrauskas J S Trier B N Fields J L Wolf 《Journal of virology》1990,64(4):1830-1833
Oral inoculation of suckling mice with reovirus serotype 1 (strain Lang) results in the conversion of intact virions to intermediate subviral particles (ISVPs) in the intestinal lumen. Digestion of virus in vitro with chymotrypsin or trypsin reveals two distinct forms of ISVPs, while the predominant species of ISVPs found in the small intestinal lumen appears to be identical to the chymotrypsin product. The in vivo conversion of virions to ISVPs was blocked by pretreatment of mice with protease inhibitors, resulting in inefficient replication of reovirus in intestinal tissue. The early inhibition of viral replication in suckling mice pretreated with protease inhibitors was not observed when suckling mice were inoculated with ISVPs generated by in vitro digestion with either chymotrypsin or trypsin. However, replication was decreased during secondary rounds of replication in mice receiving repeated doses of protease inhibitors, suggesting that luminal proteolytic digestion is important in rendering progeny virions infectious in the gut. 相似文献
92.
Duplication of an Xp segment that includes the ZFX locus causes sex inversion in man 总被引:6,自引:6,他引:0
Gerd Scherer Werner Schempp Carlo Baccichetti Elisabetta Lenzini Franca Dagna Bricarelli Laura Doria Lamba Carbone Ulrich Wolf 《Human genetics》1989,81(3):291-294
Summary Two 46,XY females with tandem duplications of an X short arm segment were studied by cytogenetic and Southern blot analysis. The results show that the duplicated segment in each case included the Xp21.2–Xp22.2 interval, resulting in a double dose of ZFX on the single active X chromosome. The results from our two cases, in conjunction with those reported by other workers, lead us to conclude that the duplication is the reason for the sex inversion. If ZFY and ZFX are indeed sex-determining gene loci, these findings favour a model of sex determination characterized by antagonistic interaction between these genes. 相似文献
93.
Synthesis and properties of 5-azido-UDP-glucose. Development of photoaffinity probes for nucleotide diphosphate sugar binding sites 总被引:5,自引:0,他引:5
R R Drake R K Evans M J Wolf B E Haley 《The Journal of biological chemistry》1989,264(20):11928-11933
A new active site directed photoaffinity probe, which is a model compound for studying nucleotide diphosphate sugar binding proteins, has been synthesized by coupling 5-azido-UTP and [32P]Glc-1-P using yeast UDP-glucose pyrophosphorylase to produce [beta-32P]5-azidouridine 5'-diphosphoglucose (5N3UDP-Glc). This probe has photochemical properties similar to that of 5-azidoUTP (Evans, R. K., and Haley, B. E. (1987) Biochemistry 26, 269-276). The efficacy of 5N3UDP-Glc as an active site directed probe was demonstrated using yeast UDP-Glc pyrophosphorylase. Saturation effects of photoinsertion were observed with an apparent Kd of 51 microM and the natural substrate, UDP-Glc, prevented photoinsertion of [beta-32P]5N3UDP-Glc with an apparent Kd of 87 microM. Prevention of photoinsertion was also seen with UTP and pyrophosphate with apparent Kd values less than 200 microM. UMP, UDP, ATP, and GTP were much less effective competitors. Selective photoinsertion was observed with several partially purified enzymes including UDP-Glc dehydrogenase, UDP-Gal-4-epimerase, Gal-1-P uridyltransferase, and phosphorylase a. The absence of nonselective photoinsertion into bulk proteins was demonstrated with crude homogenates of rabbit liver as well as with several UDP-Glc binding proteins. Of the six purified enzymes tested, only phosphoglucomutase has been shown to incorporate radiolabel from the photoprobe in the absence of UV irradiation. These results and a discussion of the utility of 5N3UDP-Glc for detecting UDP-Glc binding proteins and isolating active site peptides are presented. 相似文献
94.
95.
Identification of proteins encoded by Epstein-Barr virus trans-activator genes. 总被引:11,自引:6,他引:5
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Specific antisera were generated to characterize Epstein-Barr virus proteins reported to have trans-activating properties. Open reading frame BRLF1 was found to be expressed in two modifications in vivo, with molecular sizes ranging from 94 to 98 kilodaltons (kDa) depending on the cell line, whereas only one protein (Raji cells, 96 kDa) was detected by in vitro translation. Open reading frame BZLF1 encoded polypeptides of 38 and 35 kDa and additional smaller forms. A BZLF1-encoded 30-kDa protein could be detected under conditions in which expression was restricted to immediate early genes. Nuclear localization could be detected under conditions in which expression was restricted to immediate early genes. Nuclear localization could be shown for the proteins derived from reading frames BZLF1 and BMLF1. BMLF1 expression gave a heterogeneous protein pattern, with molecular sizes between 45 and 70 kDa, including a predominant 60-kDa protein detected in different B-cell lines. 相似文献
96.
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99.
Collection and quality of rhesus monkey semen 总被引:2,自引:0,他引:2
S E Lanzendorf P M Gliessman A E Archibong M Alexander D P Wolf 《Molecular reproduction and development》1990,25(1):61-66
Electroejaculation is an accepted method of semen collection from nonhuman primates. Although both penile and rectal probe stimulation techniques have been used, there has been a general lack of consistency and detail regarding their application. This report describes the collection, processing, and evaluation of rhesus monkey semen contrasting two methods of penile electroejaculation: 1) a constant-voltage method where stimulus current is a variable and 2) a constant-current method where stimulus current is operator-controlled. The constant-current method was the more efficient procedure, requiring a lower stimulus current for successful electroejaculation. The influence on semen quality of potentially toxic agents used in the procedure, surgical glove powder and electrolyte cream, was tested; both were detrimental as measured by motility loss. No correlation was found between coagula volume and sperm numbers. The intra- and interanimal variability in semen samples from six monkeys was also evaluated. Penile electroejaculation, combined with control of stimulus current, provides a consistent, successful, and humane method for the collection of semen in the rhesus monkey. 相似文献
100.
Tonia S. Agin J. Robert Cantey Edgar C. Boedeker Marcia K. Wolf 《FEMS microbiology letters》1996,144(2-3):249-258
Abstract A number of enteric pathogens, including enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli , Hafnia alvei , a strain of Citrobacter freundii , and rabbit EPEC strain RDEC-1 cause attaching-effacing (AE) lesions in the gut mucosa. These bacteria have a pathogenicity cassette (locus of enterocyte effacement or LEE) containing the eaeA gene. This gene encodes intimin, an outer membrane protein required for production of AE lesions. RDEC-1, a non-invasive enteropathogen in young rabbits, produces AE lesions morphologically indistinguishable from lesions caused by human AE bacterial strains. The RDEC-1 example of E. coli diarrhea in rabbits is an important model for studying the pathogenesis of AE bacteria in a natural infection and for analyzing specific roles of the components of LEE. In order to better understand the role of intimin in the development of AE lesions, a portion of DNA within RDEC-1 LEE, containing the eaeA gene and an upstream open reading frame (ORF), was sequenced. The RDEC-1 eaeA gene shared 87%, 92%, and 93% DNA sequence identity and > 80% amino acid sequence identity with the eaeA genes of C. freundii biotype 4280, EHEC O157:H7, and EPEC O127:H6, respectively. The carboxy-terminal 280 amino acid residues of intimin has 80%, 56%, and 54% identity with C. freundii , EHEC O157:H7, and EPEC O127:H6 intimins, respectively. The predicted protein encoded by the upstream ORF (156 amino acids) shares 95%, 97%, and 99% amino acid identity with predicted proteins from C. freundii , EHEC O157:H7, and EPEC O127:H6, respectively. The high degree of sequence homology of the ORF and the eaeA gene of RDEC-1 with those of other AE bacteria suggests an evolutionary relationship of LEE and supports and facilitates the use of the RDEC-1 model for studying the role of LEE in pathogenesis. 相似文献