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231.
232.
鼻蝇亚科(Rhiniinae)是双翅目丽蝇科(Calliphoridae)中比较特殊的一大类群,因此也有人把它从丽蝇科分出,独立成科的。其特征有口上片突出如鼻状,后头上部大半是裸出的,约占整个头的宽度的范围内连粉被也缺如;r脉的上方沿后侧有一列明晰的小刚毛,翅下大结节上无立纤毛,下腋瓣裸。主要分布在东洋区、非洲区、大洋洲区以及古北区南缘。目前全世界已知有22个属,近300种,曾有报道其幼虫寄生于白蚁巢内及蝗 相似文献
233.
234.
Shiaw-Der Yang Jen-Shin Song Yao-Tsung Hsieh Hui-Wen Liu Wen-Hsiung Chan 《Journal of Protein Chemistry》1992,11(5):539-546
The ATP·Mg-dependent protein phosphatase activating factor (Fa) has been identified and purified to near homogeneity from brain. In this report, as evidenced on SDS-polyacrylamide gel electrophoresis followed by autoradiography, factorFa has further been identified as a cAMP and Ca2+-independent brain kinase that could phosphorylate synapsin I, a neuronal protein that coats synaptic vesicles, binds to cytoskeleton, and is believed to be involved in the modulation of neurotransmission. Kinetic study further indicated that factorFa could phosphorylate synapsin I with a lowK
m
value of about 2 µM and with a molar ratio of 1 mol of phosphate per mole of protein. Peptide mapping analysis revealed that factorFa specifically phosphorylated the tail region of synapsin I but on a unique site distinct from those phosphorylated by Ca2+/calmodulin-dependent protein kinase II and cAMP-dependent protein kinase, the two well-established synapsin I kinases. Functional study further revealed that factorFa could phosphorylate this unique specific site on the tail region of synapsin I and thereby inhibit cross-linking of synapsin I with microtubules. The results further suggest the possible involvement of factorFa as a synapsin I kinase in the regulation of axonal transport process of synaptic vesicles via the promotion of vesicles motility during neurotransmission. 相似文献
235.
Dipak K. Das Richard M. Engelman Xuekun Liu Swapna Maity John A. Rousou Joseph Flack Jitendra Laksmipati Randall M. Jones M. Renuka Prasad David W. Deaton 《Molecular and cellular biochemistry》1992,111(1-2):77-86
Reperfusion injury occurs during open-heart surgery after prolonged cardioplegic arrest. Cardiopulmonary bypass also is known to cause hemolysis. Since reperfusion of ischemic myocardium is associated with the generation of oxygen free radicals, and since free radicals can attack a protein molecule, it seems reasonable to assume that hemolysis might be the consequence of free radical attack on hemoglobin protein. The results of this study demonstrated that reperfusion following ischemic arrest caused an increase in free hemoglobin and free heme concentrations, simultaneously releasing free iron and generating hydroxyl radicals. In vitro studies using pure hemoglobin indicated that superoxide anion generated by the action of xanthine oxidase on xanthine could release iron from the heme ring and cause deoxygenation of oxyhemoglobin into ferrihemoglobin. This study further demonstrated that before the release of iron from the heme nucleus, oxyhemoglobin underwent deoxygenation to ferrihemoglobin. The released iron can catalyze the Fenton reaction, leading to the formation of cytotoxic hydroxyl radical (OH·). In fact, the formation of OH. in conjunction with hemolysis occurs during cardiac surgery, and when viewed in the light of the in vitro results, it seems likely that oxygen-derived free radicals may cause hemolysis during cardiopulmonary bypass and simultaneously release iron from the heme ring, which can catalyze the formation of OH·. 相似文献
236.
Karel Indrak Vaclav Brabec Jarmila Indrakova Ladislav Chrobak Adriana Sakalova Marie Jarosova Jaroslav Cermak You-jun Fei Ferdane Kutlar Yuan-chao Gu Erol Baysal Titus H. J. Huisman 《Human genetics》1992,88(4):399-404
Summary We have identified different -thalassemia mutations in 93 members of 34 families of Czech or Slovakian descent using gene amplification, hybridization with specific 32P-labeled oligonucleotide probes, sequencing of amplified DNA, and gene mapping. The GA mutation at IVS-I-1 was found in 18 families; other Mediterranean mutations were IVS-II-1 (GA), IVS-II-745 (CG), IVS-I-110 (GA), and codon 39 (CT); these were present in 9 additional families. The GT mutation at codon 121, known to cause Heinzbody -thalassemia, was present in 3 families, and the frameshift at codons 82/83 (-G), first described in the Azerbaijanian population, in 2 families. A newly discovered allele was a frameshift at codons 38/39 (-C). One -thalassemia allele was incompletely characterized. We observed in 2 families a TC mutation at position +96 UTR (untranslated region) relative to the termination codon; this mutation likely is a rare polymorphism, -Thalassemia was rare; only one person carried the -3.7 heterozygosity, and one other had a yet to be identified -thalassemia-1, while seven had the anti 3.7 triplication. 相似文献
237.
The m gamma delta-1 element, a small gamma delta (Tn1000) derivative useful for plasmid mutagenesis, allele replacement and DNA sequencing. 总被引:9,自引:0,他引:9
C M Berg N B Vartak G Wang X Xu L Liu D J MacNeil K M Gewain L A Wiater D E Berg 《Gene》1992,113(1):9-16
Transposon gamma delta (Tn1000), a 6-kb member of the Tn3 family, is widely used for plasmid mutagenesis. A 1.8-kb derivative of gamma delta was constructed that contains the kan gene from Tn5 and the resolution (res) site from gamma delta cloned between 40-bp inverted repeats of gamma delta's delta (delta) end. This element, named m gamma delta-1, lacks the genes encoding transposase and resolvase, and therefore depends on its host to supply transposition and resolution functions. Thus, in strains lacking gamma delta, m gamma delta-1 will not transpose. The m gamma delta-1 element is shown to be useful for mutagenesis of plasmids, DNA sequencing, and allele replacement (in Streptomyces avermitilis). 相似文献
238.
L H Hwang B F Chen P J Lee S Y Ho J J Liu 《Biotechnology and applied biochemistry》1992,16(2):171-181
A retroviral vector has been employed to express the cDNA coding for porcine growth hormone (pGH) in the mouse fibroblast cell NIH 3T3 in large quantity. In this study, a single gene vector which contained no selectable marker was used. We have coinfected NIH 3T3 cells with pGH retrovirus and Neo(r) retrovirus to obtain a stable, high-expression clone. Using a superinfection strategy, we further increased the copy number of proviral DNA in the host chromosome, thus increasing the pGH secretion from 22 to 55 micrograms/10(6) cells/24 h. The recombinant pGH produced from mouse fibroblast cells was heterogeneous at the N-terminus, which mimicked the situation with bovine growth hormone either from natural sources or from recombinant products derived from mouse fibroblasts. This technology is useful for many biologically important genes to be stably transduced by retroviral vector into mammalian cells and highly expressed. 相似文献
239.
Direct detection of circulating free radicals in the rat using electron spin resonance spectrometry.
We developed a new technique for directly observing in vivo free radical formation in the circulating blood of living rats using electron spin resonance (ESR) spectrometry without any labeling or trapping agents. It was found that a doublet peak spectrum was obtained following ferric citrate and ascorbic acid injection. The signals were confirmed in different ways to be due to ascorbic acid radicals. These results provide evidence to support the involvement of free radical intermediates in iron-ascorbic acid reactions, and further confirm the suggested mechanisms of both the adverse and protective effects of ascorbic acid in biological systems. Furthermore, this method of direct observation is a new application of ESR spectrometry to living animals. 相似文献
240.