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51.
圆瓣姜花根茎挥发油的化学成分   总被引:1,自引:0,他引:1  
利用水蒸汽蒸馏法提取圆瓣姜花根茎挥发油,运用毛细管气相色谱-质谱联用法对挥发油进行了分析,分离出60个峰,鉴定了其中的51种成分,所鉴定成分占挥发油总量的97.32%,其主要化学成分为单萜及倍半萜类化合物。  相似文献   
52.
大鼠子宫内膜异位模型的建立与组织学观察   总被引:8,自引:1,他引:7  
目的为开发诊治子宫内膜异位症(endometriosis,EMT)的新药研究提供理想的动物模型。方法取雌性未交配性成熟大鼠,术前雌激素诱导,麻醉开腹取部份右侧子宫,将内膜种植于左腹壁内,术后16周取出包块,进行组织形态学、组织化学观察。结果异位内膜在腹壁内生长,呈隆起囊状小包块,内有黏液,具有正常子宫内膜基本组织结构,囊腔较大。异位内膜中有糖原、RNA的存在。结论该手术方法建立的子宫异位内膜生长良好,术后一周就可摸及包块大小,为开发研究子宫内膜异位症的新药提供了方便。  相似文献   
53.

Background  

The bacterial endospore (spore) has recently been proposed as a new surface display system. Antigens and enzymes have been successfully exposed on the surface layers of the Bacillus subtilis spore, but only in a few cases the efficiency of expression and the effective surface display and have been determined. We used this heterologous expression system to produce the A subunit of the urease of the animal pathogen Helicobater acinonychis. Ureases are multi-subunit enzymes with a central role in the virulence of various bacterial pathogens and necessary for colonization of the gastric mucosa by the human pathogen H. pylori. The urease subunit UreA has been recognized as a major antigen, able to induce high levels of protection against challenge infections.  相似文献   
54.

Background  

Sporulation, characteristic for some bacteria such as Bacillus subtilis, has not been entirely defined yet. Protein phosphatase E (PrpE) and small, acid soluble spore proteins (SASPs) influence this process. Nevertheless, direct result of PrpE interaction on SASPs content in spore coat of B. subtilis has not been evidenced so far. As proteomic approach enables global analysis of occurring proteins, therefore it was chosen in this experiment to compare SASPs occurrence in two strains of B. subtilis, standard 168 and ΔprpE, lacking PrpE phosphatase. Proteomic analysis is still a challenge, and despite of big approach in mass spectrometry (MS) field, the identification reliability remains unsatisfactory. Therefore there is a rising interest in new methods, particularly bioinformatic tools that would harden protein identification. Most of currently applied algorithms are based on MS-data. Information from separation steps is not still in routine usage, even though they also provide valuable facts about analyzed structures. The aim of this research was to apply a model for peptides retention times prediction, based on quantitative structure-retention relationships (QSRR) in SASPs analysis, obtained from two strains of B. subtilis proteome digests after separation and identification of the peptides by LC-ESI-MS/MS. The QSRR approach was applied as the additional constraint in proteomic research verifying results of MS/MS ion search and confirming the correctness of the peptides identifications along with the indication of the potential false positives and false negatives.  相似文献   
55.
Loss of the Salmonella MsbB enzyme, which catalyzes the incorporation of myristate destined for lipopolysaccharide in the outer membrane, results in a strong phenotype of sensitivity to salt and chelators such as EGTA and greatly diminished endotoxic activity. MsbB- salmonellae mutate extragenically to EGTA-tolerant derivatives at a frequency of 10(-4) per division. One of these derivatives arose from inactivation of somA, which suppresses sensitivity to salt and EGTA. Here we show that a second mode of MsbB- suppression is a RecA-dependent deletion between two IS200 insertion elements present in Salmonella enterica serovar Typhimurium strain ATCC 14028 but not in two other wild-type strains, LT2 and SL1344, which lack one of the IS200 elements. This deletion occurs spontaneously in wild-type and MsbB- strain 14028 salmonellae and accounts for about one-third of all of the spontaneous suppressors of MsbB- in strain 14028. It spans the region corresponding to 17.7 to 19.9 centisomes, which includes somA, on the sequenced map of Salmonella LT2 (136 ORFs in that strain; ATCC 14028 and other strains showed variability in this region). In addition to conferring EGTA resistance correlated with somA, the deletion confers a MacConkey galactose resistance phenotype on MsbB- Salmonella, indicating that at least one additional gene (distinct from somA) within the deletion is responsible for this phenotype. In the wild type, the deletion mutant grows with normal exponential growth rate in Luria broth but is chlorate resistant and does not grow on citrate agar. The deletion strains have lost hydrogen sulfide production, nitrate reductase activity, and gas production from glucose fermentation.  相似文献   
56.
Experiencing the New Genetics: Family and Kinship on the Medical Frontier. Kaja Finkler. Philadelphia: University of Pennsylvania Press, 2000. 296 pp.
Born and Bred: Idioms and New Reproductive Technologies in England. Jeanette Edwards. New York: Oxford University Press, 2000. 264 pp.  相似文献   
57.
58.
We report the genomic organization and deduced protein sequence of a cephalochordate member of the Otx homeobox gene family (AmphiOtx) and show its probable single-copy state in the genome. We also present molecular phylogenetic analysis indicating that there was single ancestral Otx gene in the first chordates which was duplicated in the vertebrate lineage after it had split from the lineage leading to the cephalochordates. Duplication of a C-terminal protein domain has occurred specifically in the vertebrate lineage, strengthening the case for a single Otx gene in an ancestral chordate whose gene structure has been retained in an extant cephalochordate. Comparative analysis of protein sequences and published gene expression patterns suggest that the ancestral chordate Otx gene had roles in patterning the anterior mesendoderm and central nervous system. These roles were elaborated following Otx gene duplication in vertebrates, accompanied by regulatory and structural divergence, particularly of Otx1 descendant genes.   相似文献   
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