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1.
M. A. Riddin G. J. Venter K. Labuschagne M. H. Villet 《Medical and veterinary entomology》2019,33(4):467-475
An upsurge in African horse sickness (AHS) in the Eastern Cape, South Africa, from 2006 led to an epidemiological reassessment of the disease there. Light trapping surveys carried out near horses, donkeys and zebras in 2014–2016 collected 39 species of Culicoides midge (Diptera: Ceratopogonidae) that are potential vectors of AHS. To establish if these midges fed on equids, DNA sequences were obtained from the gut contents of 52 female midges (35 freshly blood‐fed, 13 gravid and four parous), representing 11 species collected across 11 sites. Culicoides leucostictus fed on all three equids. Culicoides bolitinos, Culicoides imicola and Culicoides magnus fed on both horses and donkeys. Culicoides onderstepoortensis fed on donkeys, and Culicoides similis and Culicoides pycnostictus fed on zebras. Bloodmeals from cows, pigs, warthogs, impalas and a domestic dog were also identified in various species, but none of the midges tested had fed on birds. These results contribute to knowledge of the vectorial capacity of several species of Culicoides with regard to AHS in the Eastern Cape and point to potential reservoir hosts, of which donkeys, zebras and domestic dogs have previously been found to harbour AHS. Blood‐fed midges were also obtained throughout winter, indicating the potential for endemic AHS in the province. 相似文献
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G. J. Venter J. T. Paweska A. A. Van Dijk P. S. Mellor W. J. Table Ick 《Medical and veterinary entomology》1998,12(4):378-385
Abstract .The susceptibility of field-collected Culicoides bolitinos to infection by oral ingestion of bluetongue virus serotypes 1, 3 and 4 (BLU 1, 3 and 4) was compared with that of field-collected C. imicola and laboratory reared C. variipennis sonorensis . The concentration of the virus per millilitre of bloodmeal was 105.0 and 106.0 TCID50 for BLU 4 and 107.2 TCID50 for BLU 1 and 3. Of 4927 C. bolitinos and 9585 C. imicola fed, 386 and 287 individual midges survived 10 days extrinsic incubation, respectively. Midges were assayed for the presence of virus using a microtitration assay on BHK-21 cells and/or an antigen capture ELISA. Infection prevalences for the different serotypes as determined by virus isolation ranged from 22.7 to 82.0% in C. bolitinos and from 1.9 to 9.8% in C. imicola; infection prevalences were highest for BLU 1, and lowest for BLU 4 in both species. The mean log10 TCID50 titre of the three BLU viruses per single fly was higher in C. bolitinos than in C. imicola . The results suggested that C. bolitinos populations are capable vectors of the BLU viruses in South Africa. A high correlation was found between virus isolation and ELISA results for the detection of BLU 1, and less for BLU 4; the ELISA failed to detect the presence of BLU 3 in infected flies. The C. v. sonorensis colonies had a significantly lower susceptibility to infection with BLU 1, 3 and 4 than C. bolitinos and C. imicola . However, since infection prevalence of C. v. sonorensis was determined only by ELISA, this finding may merely reflect the insensitivity of this assay at low virus titres, compared to virus isolation. 相似文献
4.
Continuous high density expression of human beta 2-adrenergic receptors in a mouse cell line previously lacking beta-receptors 总被引:1,自引:0,他引:1
The PvuII fragment of human genomic clone LCV-517 which contains the entire coding region of a beta-adrenergic receptor gene was cloned into the SmaI site of the expression vector pMSG. The recombinant DNA was cotransfected with pRSVneo into mouse B-82 cells using the CaPO4 precipitation method. B-82 cells do not possess beta-adrenergic receptors but do contain prostaglandin E1 receptors that stimulate adenylate cyclase. Following transfection, several colonies expressing beta-adrenergic receptors were isolated. Analysis of ligand binding to expressed beta-receptors indicated that the protein encoded by the gene in clone LCV-517 was a beta 2-adrenergic subtype. Human beta 2-adrenergic receptors photoaffinity labeled with [125I]iodocyanopindolol diazirine migrated on sodium dodecyl sulfate-polyacrylamide gels consistent with a molecular mass of 68,000, demonstrating that the receptor is glycosylated to an extent of 25-30% by weight. Addition of isoproterenol to cultures of transfected cells resulted in a 3-4-fold stimulation of adenylate cyclase, an effect similar to that seen in control B-82 cells with prostaglandin E1. These data describe the production of stable murine clonal cell lines expressing human beta 2-adrenergic receptors and illustrate the utility of such lines in the biochemical and pharmacological characterization of receptor proteins. 相似文献
5.
M H Polymeropoulos H Xiao A Glodek M Gorski M D Adams R F Moreno M G Fitzgerald J C Venter C R Merril 《Genomics》1992,12(3):492-496
Expressed sequence tags (ESTs) have been obtained from several hundred brain cDNAs as an initial effort to characterize expressed brain genes. These ESTs will become tools for human genome mapping and they will also provide candidate causative genes for inherited disorders affecting the central nervous system. We have developed a procedure for the rapid chromosomal assignment of these ESTs: cDNA sequences are first analyzed by a computer program to determine regions likely not to be interrupted by introns in the genomic DNA. A pair of oligonucleotide primers is then designed to amplify this region by the polymerase chain reaction using DNA template from human-rodent somatic cell hybrid chromosomal panels. The chromosomal assignment of the cDNA is determined by studying the segregation of the amplified products in these panels. In this paper we describe the mapping of 46 brain ESTs, as well as observations on the amplification of rodent sequences. 相似文献
6.
Discrepancies between the affinities of binding and action of the novel beta-adrenergic agonist BRL 37344 in rat brown adipose tissue 总被引:2,自引:0,他引:2
P Muzzin J Seydoux J P Giacobino J C Venter C Fraser 《Biochemical and biophysical research communications》1988,156(1):375-382
The novel brown adipose tissue (BAT) selective beta-adrenergic agonist, BRL 37344, is 31-fold more potent than (-)-isoproterenol in stimulating the respiratory rate of interscapular BAT fragments. BRL 37344 is also more potent (9-fold) than (-)-isoproterenol in stimulating adenylate cyclase activity of IBAT purified plasma membranes whereas, in the same preparation, it is 81-fold less potent than (-)-isoproterenol in competition displacement studies with the beta-adrenergic ligand, [125I]cyanopindolol. We have previously demonstrated that the photoaffinity reagent [125I]cyanopindolol-diazirine selectively labels a 62 kDa protein in IBAT plasma membranes that displays pharmacological properties of a beta 1-adrenergic subtype. Relatively high concentrations of BRL 37344 (10 microM) are required to displace [125I]cyanopindolol-diazirine binding to the 62 kDa protein. Taken together, the results suggest that two different populations of beta-adrenergic receptors may co-exist in BAT plasma membranes: a small population (about 15%) of atypical beta-receptors and a large population of beta 1-receptors that exhibit high and low affinities for BRL 37344, respectively. 相似文献
7.
An imported 13-year-old Simmentaler cow was presented with severe purulent cervicitis and endometritis from which Corynebacterium pyogenes , Fusobacterium necrophorum , Bacteroides melaninogenicus and an untyped Clostridium perfringens were isolated. The endometritis responded to treatment but the cervix did not and remained fibrous, continuously patent and purulent. Natural pregnancy was considered unlikely and the cow was prepared as an embryo transfer donor. Eight embryos were recovered and six transferred, resulting in five confirmed pregnancies and four live births. 相似文献
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9.
Maryna van de Venter Derek Litthauer Willem Oelofsen 《Journal of cellular biochemistry》1994,54(1):1-10
Adipocyte precursors from the stromal vascular fraction of human adipose tissue were allowed to differentiate in serum-free defined medium, whereafter their catecholamine stimulated lipolytic response was compared to that of mature isolated human adipocytes. Seventy-five to ninety percent of the fibroblast-like cells accumulated lipid droplets and glycerol-3-phosphate dehydrogenase activities of 1,000–2,800 mU/mg protein were measured in cell homogenates of differentiated cells. Lipolysis could be stimulated by both isoproterenol and norepinephrine in both differentiated preadipocytes as well as mature adipocytes. The results obtained with β-adrenergic agents suggested the presence of a higher affinity receptor in differentiated preadipocytes as compared to mature adipocytes. Mature adipocytes responded well to β-adrenergic agents, but no antilipolytic α2-adrenergic response was observed in the differentiated preadipocytes. The presence of Gi proteins in the differentiated preadipocytes was suggested by the antilipolytic effect of adenosine as well as the lipolytic activity generated by pertussis toxin. In conclusion, our medium supported the differentiation of a very high percentage of human preadipocytes which developed a sensitive β-adrenergic lipolytic response but which lacked an α2-adrenergic antilipolytic response. 相似文献
10.
Martine de Boer Maaike te Lintel Hekkert Jiang Chang Bibi S. van Thiel Leonie Martens Maxime M. Bos Marion G. J. de Kleijnen Yanto Ridwan Yanti Octavia Elza D. van Deel Lau A. Blonden Renata M. C. Brandt Sander Barnhoorn Paula K. Bautista-Niño Ilona Krabbendam-Peters Rianne Wolswinkel Banafsheh Arshi Mohsen Ghanbari Christian Kupatt Leon J. de Windt A. H. Jan Danser Ingrid van der Pluijm Carol Ann Remme Monika Stoll Joris Pothof Anton J. M. Roks Maryam Kavousi Jeroen Essers Jolanda van der Velden Jan H. J. Hoeijmakers Dirk J. Duncker 《Aging cell》2023,22(3):e13768