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51.
Pony mares which were detected pregnant by transrectal ultrasonography received a single intrauterine infusion of either sterile saline (control, n = 12 mares) or 10(6)Candida parapsilosis (treated, n = 12 mares) between Days 11 to 14 postovulation. Subsequent embryonic loss was studied by daily ultrasonography of the mare's uterus, by serum progesterone levels, by endometrial swabs for cytologic and microbiologic examination and by endometrial biopsies that were taken after embryonic loss was detected. Significantly fewer (P<0.01) embryonic losses occurred in control than in treated mares (4 12 vs 12 12 ). The mean interval from intrauterine infusion until embryonic loss was 5.8 +/- 2.8 d for control mares (n = 4) and 2.1 +/- 0.2 d for treated mares (n = 12). Prior to embryonic loss, moderate to marked edema of the endometrial folds in 12 of 12 treated mares and free fluid in the uterine lumen of 5 of 12 treated mares were detected by ultrasonography. After embryonic loss, Candida parapsilosis was cultured from the uteri of 8 of 12 treated mares, and E . coli was cultured from the uteri of 2 of 4 control mares. Postloss endometrial smears had cytologic evidence of inflammation in 10 of 12 treated mares and 3 of 4 control mares. Intrauterine inoculation of C. parapsilosis consistently induced embryonic loss and may provide a basis to further study the relationship between endometritis and embryonic loss in mares. 相似文献
52.
DNA-binding activity associated with the v-myb oncogene product is not sufficient for transformation. 总被引:5,自引:1,他引:4 下载免费PDF全文
The product of the v-myb oncogene of avian myeloblastosis virus is a nuclear protein with an associated DNA-binding activity. We demonstrated that the highly conserved amino-terminal domain of p48v-myb is required for its associated DNA-binding activity. This activity is not required for the nuclear localization of p48v-myb. Furthermore, the associated DNA-binding activity and nuclear localization of p48v-myb together are not sufficient for transformation. 相似文献
53.
Almond plants (Amygdalus communis L. cv. Garrigues) were grown in the field under drip irrigated and non irrigated conditions. Leaf water potential () and leaf conductance (g1) were determined at three different times of the growing season (spring, summer and autumn). The relationships between and g1 in both treatments showed a continuous decrease of g1 as decreased in spring and summer. Data from the autumn presented a threshold value of (approx. –2.7 MPa in dry treatment, and approx. –1.4 MPa in wet treatment) below which leaf conductance remained constant. 相似文献
54.
Human melanocyte cultures were established using disaggregated epidermal cell suspensions derived from foreskins and plated onto culture dishes in medium containing 2% fetal bovine serum, growth factors, hormones, and melanocyte growth factor (MGF) extracted from bovine hypothalamus (Wilkins et al., J.Cell. Physiol., 122:350, 1985). After 2 days in culture the cells were transferred to serum-free medium to eliminate keratinocyte and fibroblast growth. Melanocytes grew preferentially and pure melanocyte populations could be harvested after 12-16 days in vitro. Melanocytes were later subcultured in the presence of 1% FBS. Pure melanocyte cultures were characterized by light and electron microscopic criteria, as well as by cytochemical demonstration of the melanocyte-specific enzyme, tyrosinase. At the ultrastructural level, cultured melanocytes derived from black (negroid) neonatal skin (B-M) had numerous mature rod-shaped stage IV melanosomes, while white (caucasoid) skin-derived melanocytes (W-M) in culture contained no mature melanosomes. Growth rate, cell yield, and in vitro lifespan for B-M were more than twice that for W-M in pure melanocyte cultures in the presence of MGF. Our results suggest that MGF-dependent growth of B-M differs from that of W-M. 相似文献
55.
A E Garcia G Gupta M H Sarma R H Sarma 《Journal of biomolecular structure & dynamics》1988,6(3):525-542
The oligomer d(GCCGCAGC) can adopt two different conformations: i) a duplex with two mismatched A.C base pairs and ii) a hairpin with two C.G base pairs and a single stranded loop. We report molecular mechanics, normal mode analysis, and thermodynamic stability calculations for both structures. We show that the energy-minimized structure and harmonic-dynamics results are in complete agreement with the observed NOE spectrum and imino proton exchange data. We conclude that the high stability of the hairpin structure over the duplex at low salt concentration is due to the higher vibrational entropy contribution to the system free energy by the single stranded loop and to the lack of minor groove phosphate/phosphate electrostatic repulsions that tend to destabilize the duplex. 相似文献
56.
Simone Grinfeld Paul Jacquet Jan Gilles Lucile Baugnet-Mahieu 《Development genes and evolution》1988,197(5):302-304
Summary In some strains of mice, eggs when X irradiated during the pronuclear stage, undergo a mitotic block in the G2 phase of the first cell cycle and cleave when the second division takes place in controls. The importance of this effect varies considerably with the strain and depends exclusively on the maternal genotype. In previous work, two-dimensional electrophoresis showed that eggs blocked at the one-cell stage after irradiation, undergo the same modifications in polypeptide synthesis as two-cell controls of the same age, except at the time of normal first mitosis, where three polypeptide sets of 30, 35 and 45 kDa appear only in cleaving controls. In the present study, we have found phosphorylations in dividing controls, on polypeptides of 30, 35 and 45 kDa. These phosphorylations are not seen in blocked irradiated eggs. 相似文献
57.
58.
Nestor Cortez Augusto F. Garcia Monier H. Tadros Nasser Gad'on Emil Schiltz Gerhart Drews 《Archives of microbiology》1992,158(5):315-319
Labelling of Rhodobacter capsulatus cells with (32P)Pi in a phototrophic culture results in phosphorylation of a membrane-bound polypeptide identified as the subunit of the LHI antenna complex of the photosynthetic apparatus. Phosphorylation of the same polypeptide was also observed by incubation of chromatophores with (32P)ATP or under conditions of photophosphorylation with ADP and (32P)Pi. The identity of the phosphorylated LHI- subunit was demonstrated by N-terminal protein sequencing of the phosphorylated polypeptide and by failure of labelling in LHI-defective mutants. Pre-aeration of the samples or addition of the oxidant potassium ferrcyanide stimulated the kinase activity whereas the presence of soluble cytoplasmic proteins impaired phosphorylation in an in vitro assay. No effect resulted from addition of reductants to the assay medium. The results indicate the presence of a membrane-bound protein kinase in R. capsulatus that phosphorylates the subunit of the LHI antenna complex under redox control.Abbreviations Pi
inorganic phosphate
- SDS-PAGE
sodium dodecyl-sulfate polyacrylamide gel electrophoresis 相似文献
59.
Analysis of the human regulators of complement activation (RCA) gene cluster with yeast artificial chromosomes (YACs). 总被引:6,自引:0,他引:6
D Hourcade A D Garcia T W Post P Taillon-Miller V M Holers L M Wagner N S Bora J P Atkinson 《Genomics》1992,12(2):289-300
The human regulators of complement activation gene cluster (RCA cluster) have been partially characterized with yeast artificial chromosomes (YACs). While the data confirm many points previously elucidated, the finer resolution of YAC mapping has allowed the discovery and/or localization of partial gene duplications, the determination of gene orientations, and the measurement of gaps between known genes. Here nine overlapping YACs that encompass a genomic region of 800 kb, encoding four RCA genes and three gene-like elements, are described. The encoded genes and two of the gene-like elements share the same orientation and are ordered (5' to 3') DAF, CR2, CR1, MCP-like, CR1-like, and MCP. A C4bp-like region lies upstream from DAF and is likely to correspond to one recently observed by F. Pardo-Manuel, J. Rey-Campos, A. Hillarp, B. Dahlback, and S. Rodriguez de Cordoba (1990, Proc. Natl. Acad. Sci. USA 87: 4529-4533). MCP-like, a new genetic element, was discovered and found to be homologous to the 5' portion of the MCP gene. Two large gaps of 85 kb (between CR2 and DAF) and 110 kb (between DAF and the C4bp-like element) could carry additional RCA genes. The arrangement of CR1, MCP-like, CR1-like, and MCP, in that order, strongly suggests that this region was generated by a single duplication of neighboring CR1/CR1-like and MCP/MCP-like forerunners. The RCA YACs will now serve as convenient DNA sources for the subcloning and further characterization of this region. 相似文献
60.
Localization of the amphotropic murine leukemia virus receptor gene to the pericentromeric region of human chromosome 8. 下载免费PDF全文
The host range of retroviruses is determined primarily by the presence of specific receptors on target cells which are recognized by the retroviral envelope glycoprotein. Somatic cell hybrids have been used to determine the chromosomal locations of several retroviral receptors in mice prior to their molecular cloning. Here we report that by using human-Chinese hamster somatic cell hybrids and a retroviral vector, we have mapped the receptor for the amphotropic murine leukemia virus to the pericentromeric region of human chromosome 8. 相似文献