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71.
72.
Ancient large-scale genome duplications: phylogenetic and linkage analyses shed light on chordate genome evolution 总被引:12,自引:4,他引:8
Pebusque MJ; Coulier F; Birnbaum D; Pontarotti P 《Molecular biology and evolution》1998,15(9):1145-1159
Paralogous genes from several families were found in four human chromosome
regions (4p16, 5q33-35, 8p12-21, and 10q24-26), suggesting that their
common ancestral region underwent several rounds of large- scale
duplication. Searches in the EMBL databases, followed by phylogenetic
analyses, showed that cognates (orthologs) of human duplicated genes can be
found in other vertebrates, including bony fishes. In contrast, within each
family, only one gene showing the same high degree of similarity with all
the duplicated mammalian genes was found in nonvertebrates (echinoderms,
insects, nematodes). This indicates that large-scale duplications occurred
after the echinoderms/chordates split and before the bony vertebrate
radiation. It has been suggested that two rounds of gene duplication
occurred in the vertebrate lineage after the separation of Amphioxus and
craniate (vertebrates + Myxini) ancestors. Before these duplications, the
genes that have led to the families of paralogous genes in vertebrates must
have been physically linked in the craniate ancestor. Linkage of some of
these genes can be found in the Drosophila melanogaster and Caenorhabditis
elegans genomes, suggesting that they were linked in the triploblast
Metazoa ancestor.
相似文献
73.
In vivo and in vitro processing of seed reserve protein in the endoplasmic reticulum: evidence for two glycosylation steps 总被引:12,自引:0,他引:12 下载免费PDF全文
Cotyledons of the common bean (Phaseolus vulgaris L.) synthesize large amounts of the reserve protein phaseolin. The polypeptides are synthesized on membrane-bound polysomes, pass through the endoplasmic reticulum (ER) and accumulate in protein bodies. For a study of the biosynthesis and processing of phaseolin, developing cotyledons were labeled with radioactive amino acids, glucosamine and mannose, and isolated fractions (polysomal RNA, polysomes, and rough ER) were used for in vitro protein synthesis. Newly synthesized phaseolin present in the ER of developing cotyledons can be fractioned into four glycopolypeptides by SDS PAGE. In vitro synthesis with polysomal RNA results in the formation of two polypeptides by polysome run-off shows that glycosylation is a co-translational event. The two unglycosylated polypeptides formed by polysome run-off are slightly smaller than the two polypeptides formed by in vitro translation of isolated RNA, indicating that a signal peptide may be present on these polypeptides. Run-off synthesis with rough ER produces a pattern of four polypeptides similar to the one obtained by in vivo labeling. The two abundant glycopolypeptides formed by polysome run-off. This result indicates the existence of a second glycosylation event for the abundant polypeptides. Inhibition of glycosylation by Triton X-100 during chain-completion with rough ER was used to show that these two glycosylation steps normally occur sequentially. Both glycosylation steps are inhibited by tunicamycin. Analysis of carhohydrate to protein ratios of the different polypeptides and of trypsin digests of polypeptides labeled with [(3)H]glucosamine confirmed the conclusion that some glycosylated polypeptides contain two oligosaccharide chains, while others contain only one. An analysis of tryptic peptide maps shows that each of the unglycosylated polypeptides is the precursor for one glycosylated polypeptide with one oligosaccharide chain and one with two oligosaccharide chains. 相似文献
74.
75.
76.
Ursum J Nielen MM van Schaardenburg D van der Horst AR van de Stadt RJ Dijkmans BA Hamann D 《Arthritis research & therapy》2008,10(1):R12
Introduction
The aim of our study was to investigate the association between arthritic disease activity and antibodies to mutated citrullinated vimentin (anti-MCV), because such a relation has been suggested. 相似文献77.
In vitro zygotic embryo culture of wild banana significantly increased the germination compared to greenhouse grown seeds. Embryo orientation and BAP concentration significantly affected germination rate. These factors together with gelling agent, dark and light conditions and coconut water, also showed variable effects on the number of roots per plant, root length, shoot length, number of days to root emergence and number of days to shoot emergence. 相似文献
78.
H?Bukulmez AL?Matthews CM?Sullivan C?Chen MJ?Kraay RC?Elston RW?Moskowitz VM?Goldberg ML?WarmanEmail author 《Arthritis research & therapy》2005,8(1):R25
In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA),
we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family
histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses
to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis
of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing
total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We
compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings
of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the
siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age
and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to
identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with
hip OA than in those with knee OA. 相似文献
79.
应用免疫组织化学SP法对4例饲喂黄曲霉毒素B1的Wistar大鼠肝组织中AFB1-DNA加合物的染色及常规HE染色发现,4例肝细胞核均出现异型性,但未见肝细胞坏死、增生灶及肝细胞癌;免疫组化揭示部分肝细胞核出现棕黄色、不均质状的AFB1-DNA加合物,阳性细胞数占10~85%。结果提示免疫组织化学方法可作为一种AFB1的定位方法,AFB1在动物致癌过程中AFB1-DNA加合物可能具有启动作用 相似文献
80.
W L Hickerson S L Colgin K G Proctor 《Plastic and reconstructive surgery》1990,86(2):319-26; discussion 327-8
An island skin flap was designed on the left inferior epigastric neurovascular bundle of anesthetized male rats. Blood flow was measured in situ with a laser Doppler flowmeter at 20 discrete points on a grid system (5 points in each quadrant of the flap) before and after surgery, or before vascular occlusion, during reperfusion, and 48 to 72 hours later. Two series of experiments were performed. In the first series, the raised flap was placed in a bath containing heated Ringer's solution and the left pedicle was cross-clamped. After 30 minutes, adenosine at a concentration that produced supramaximal vasodilatation, or its vehicle, was added to the bath. After 1 hour total occlusion time, the vascular clamp was released and adenosine treatment was continued for the first 30 minutes of reperfusion. In the second series, the protocol was similar except that adenosine, or its vehicle, was infused into the ischemic flap by means of the distal stump of the right inferior epigastric artery. After 48 to 72 hours, fluorescein was injected IV. The data showed a significant regional variation in baseline laser Doppler blood flow that was further altered by surgically raising the flap. Whereas proximal axial laser Doppler blood flow was essentially unchanged from the preoperative baseline, distal axial laser Doppler blood flow decreased 10 to 50 percent, and proximal and distal dependent laser Doppler blood flow decreased 50 to 80 percent. Thus no single value accurately reflected total flap perfusion. Necrosis occurred only in the dependent flap regions, which confirmed previous work. In the dependent regions, especially along the incision line, postoperative laser Doppler blood flow was lowest.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献