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排序方式: 共有547条查询结果,搜索用时 15 毫秒
1.
2.
G H Nickerson 《CMAJ》1993,148(9):1617-1619
3.
W E Owens S C Nickerson 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1989,190(1):79-86
An anti-inflammatory factor isolated from milk of hyperimmunized cows was analyzed in vitro and in vivo. Macrophages collected from lacteal secretions of a unimmunized nonlactating cow showed increased ability to kill phagocytosed Staphylococcus aureus when incubated with the anti-inflammatory factor. Mice injected intraperitoneally with 10 mg/kg of anti-inflammatory factor demonstrated an increased LD50 to S. aureus when challenged intraperitoneally. Injected mice also demonstrated significantly (P less than 0.05) less mammary inflammation and involution and increased clearance of S. aureus when challenged intramammarily. Quantitative histologic analysis of mammary tissues from mice injected with anti-inflammatory factor demonstrated significantly (P less than 0.05) more lumen, less interalveolar connective tissue, and less leukocytic infiltration compared with control mice. Mammary glands of mice injected with anti-inflammatory factor and challenged with S. aureus also contained fewer colony-forming units than control mice. The product appeared to exert its effect on the nonspecific defense system via modulation of leukocyte function. 相似文献
4.
Dr. Stephen C. Nickerson 《Cell and tissue research》1989,255(3):675-677
Ultrastructural examination of bovine mammary tissues revealed the presence of 9+0 or primary cilia protruding from surfaces of alveolar epithelial and myoepithelial cells. Cilia of epithelial cells protruded approximately 1200 nm into lumina of alveoli and arose from a basal body centriole, the associated centriole of the diplosome, and an accessory rootlet system. Cilia on epithelial cells were more frequently observed than cilia on myoepithelial cells. Occasional cilia made contact with macrophages in the alveolar lumen. The structures were more commonly found in tissues from nonlactating cows, and most were observed in the ventral portion of the mammary gland. 相似文献
5.
Stability of the larvicidal activity of Bacillus thuringiensis subsp. israelensis: amino acid modification and denaturants. 总被引:10,自引:7,他引:3 下载免费PDF全文
The Bacillus thuringiensis subsp. israelensis mosquito larvicidal toxin is not a sulfhydryl-activated toxin. The protein disulfide bonds were cleaved and blocked without loss of toxicity. In contrast, modification of the lysine side chains eliminated toxicity. Additionally, the toxin was resistant to high concentrations of salt (8 M NaBr), organic solvents (40% methanol), denaturants (4 M urea), and neutral detergents (10% Triton X-100). However, it was inactivated by both positively and negatively charged detergents and by guanidine hydrochloride. 相似文献
6.
The calmodulin content of the yeast and mycelial phases of Ceratocystis ulmi was determined by radioimmunoassay. Calmodulin levels increased at the G1-S boundary of the cell cycle, coinciding with the first visible appearance of buds or germ tubes. However, in both phases the cellular calmodulin levels were equivalent. No differential synthesis was observed. 相似文献
7.
8.
A collection of maize obtained from the Chocó Indian tribe of Darien, Panama, differs from published accounts of maize reported as typical for the area in size and in methods of cultivation. The collection may represent a segregating population from crosses occurring between the racesChococeño andCoastal Tropical Flint. Implications of this hypothesis with regard to problems of introduction, present geographical occurrence, and transportation of these races by nomadic human vectors are briefly discussed. 相似文献
9.
Interphotoreceptor retinoid-binding protein. Gene characterization, protein repeat structure, and its evolution 总被引:8,自引:0,他引:8
D E Borst T M Redmond J E Elser M A Gonda B Wiggert G J Chader J M Nickerson 《The Journal of biological chemistry》1989,264(2):1115-1123
The gene for bovine interphotoreceptor retinoid-binding protein (IRBP) has been cloned, and its nucleotide sequence has been determined. The IRBP gene is about 11.6 kilobase pairs (kb) and contains four exons and three introns. It transcribed into a large mRNA of approximately 6.4 kb and translated into a large protein of 145,000 daltons. To prove the identity of the genomic clone, we determined the protein sequence of several tryptic and cyanogen bromide fragments of purified bovine IRBP protein and localized them in the protein predicted from its nucleotide sequence. There is a 4-fold repeat structure in the protein sequence with 30-40% sequence identity and many conservative substitutions between any two of the four protein repeats. The third and fourth repeats are the most similar pair. All three of the introns in the IRBP gene fall in the fourth protein repeat. Two of the exons, the first and the fourth, are large, 3173 and 2447 bases, respectively. The introns are each about 1.5-2.2 kb long. The human IRBP gene has a sequence that is similar to one of the introns from the bovine gene. The unexpected gene structure and protein repeat structure in the bovine gene lead us to propose a model for the evolution of the IRBP gene. 相似文献
10.
Cecilie Boysen Christopher Carlson Eran Hood Leroy Hood Deborah A. Nickerson 《Immunogenetics》1996,44(2):121-127
The T-cell receptor (TCR) is a highly variable molecule composed of two polypeptide chains that recognize antigenic peptides
in the context of major histocompatibility complex (MHC) molecules. In this study, we describe a sequence-based search for
germline polymorphisms in the variable (V) gene segments of the human TCRA/D locus. Thirty different V gene segments were amplified from six to eight unrelated individuals and sequenced from low melting point agarose. Twenty-seven
polymorphisms were identified in 15 V gene segments. These polymorphisms are mainly single nucleotide substitutions, but an insertion/deletion polymorphism and
a single dinucleotide repeat with variable length were also seen. Of the 15 sequence variations found in the coding regions,
six are silent and nine encode amino acid changes. All of the amino acid changes are found at non-conserved residues, frequently
in the hypervariable regions, where they may influence MHC and/or peptide recognition. Therefore, it is possible that germline
variations in TCR genes could influence an individual’s immune response, and may also contribute to susceptibility to diseases such as autoimmunity.
Received: 9 January 1996 / Revised: 22 February 1996 相似文献