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排序方式: 共有4670条查询结果,搜索用时 15 毫秒
941.
Ester S. Ramos Carlos A. Moreira-Filho Yvone A. M. V. A. Vicente Maria A. S. Llorach-Velludo Silvio Tucci Jr. Maria H. O. Duarte Amélia G. Araújo Lucia Martelli 《Human genetics》1996,97(5):596-598
Two 46,XX true hermaphrodites and one XX male without genital ambiguities are reported. They coexist in two generations of the same pedigree, with paternal transmission and in the absence of SRY (sex-determining region, Y chromosome). These familial cases provide evidence to support the hypothesis that these disorders are alternative manifestations of the same genetic defect, probably an autosomal dominant mutation (with incomplete penetrance) or an X-linked mutation (limited by the presence of the Y chromosome). 相似文献
942.
Lucia Monaco Roberta Tagliabue Serenella Giovanazzi Alessandra Bragonzi Marco R. Soria 《Gene》1996,180(1-2):145-150
The in vitro amplification method for heterologous gene expression in mammalian cells is based on the stable transfection of cells with long, linear DNA molecules having several copies of complete expression units, coding for the gene of interest, linked to one terminal unit, coding for the selectable marker. DNA concatenamers containing additional expression units can also be prepared: we exploited this feature by co-polymerizing expression units coding for granulocyte colony-stimulating factor (G-CSF) with cassettes for dihydrofolate reductase (DHFR) and for neomycin (Nm) resistance, as selectable markers. We were thus able to obtain high level production of G-CSF in chinese hamster ovary (CHO) dhfr- cells by combining in vitro amplification to just one step of in vivo amplification. This approach required a considerably shorter time than the classical, stepwise amplification by methotrexate. 相似文献
943.
Lucia Banci I. Bertini G. Quacquarini Olaf Walter Antonio Díaz Manuel Hervás Miguel A. de la Rosa 《Journal of biological inorganic chemistry》1996,1(4):330-340
The three-dimensional structure in solution of the reduced form of cytochrome c
6 from the green alga Monoraphidium braunii has been solved through NMR data. Cytochrome c
6 acts as a small mono-heme electron carrier protein between the two membrane-embedded complexes cytochrome f and photosystem I. The structure was determined using 1278 relevant interproton NOEs out of 1776 assigned NOEs with distance
geometry (DG) calculations which included 36 stereospecific assignments and 20 experimentally found angle constraints. The
family of structures obtained from the DG calculations was subjected to energy minimization and molecular dynamics simulation
using previously defined force field parameters for the heme and its ligands. In all stages of the calculations, the solution
structure is well defined and similar to the now available X-ray structure.
Received: 18 January 1996 / Accepted: 19 April 1996 相似文献
944.
945.
Nicla Romano Maria Rosaria Baldassini Francesca Renata Terribili Luigi Abelli Lucia Mastrolia Massimo Mazzini 《Polar Biology》1997,18(5):358-362
Lymphomyeloid organs of the Antarctic fish Trematomus bernacchii were studied with the aim of analysing some morphological aspects related to adaptation to low environmental temperature.
The thymus of T. bernacchii was flattened, incompletely lobated and scarcely regionalised. It was filled by lymphoid elements intermingled with stromal
elements. The head kidney appeared highly vascularised and mainly lymphopoietic. The spleen appeared mainly erythropoietic,
with scarcely developed areas of white pulp.
Received: 10 February 1997 / Accepted: 4 May 1997 相似文献
946.
Brown Jillian R.; Guther Maria Lucia S.; Field Robert A.; Ferguson Michael A. J. 《Glycobiology》1997,7(4):549-558
A series of hydrophobic mannosides were synthesized and testedfor their ability to act as acceptor substrates for mannosyltransferasesin a Trypanosoma brucei cell-free system. The thiooctyl -mannosidesand octyl -mannosides all accepted single mannose residues in-linkage, as judged by thin layer chromatography of the productsbefore and after jack bean -mannosidase digestion. The mannosylationreactions were inhibited by amphomycin, suggesting that theimmediate donor was dolicholphosphate-mannose (Dol-P-Man) inall cases. The transferred -mannose residues were shown to beboth 1-2 and 1-6 linked by Aspergillus phoenicis -mannosidaseand acetolysis treatments, respectively. These data suggestthat the compounds can act as acceptor substrates for the Dol-P-Mandependent 1-2 and 1-6 mannosyltransferases of the GPI biosyntheticpathway and/or the dolichol-cycle of protein N-glycosylation.One of the compounds, Man1-6Man1-O-(CH2)7CH3, inhibited endogenousGPI biosynthesis in the cell-free system, suggesting that itcould be a substrate for the trypanosome Dol-P-Man:Man2GlcN-Pl1-2 mannosyltransferase. dolichol glycosylphosphatidylinositol mannosyltransferase trypanosome 相似文献
947.
Massuo J. Kato Lucia M.X. Lopes Hipólito F. Paulino Fo Massayoshi Yoshida Otto R. Gottlieb 《Phytochemistry》1985,24(3):533-536
The fruits of Virola sebifera and V. elongata (Myristicaceae) contain three ω-phenylundecanoyl-substituted compounds, a 2,6-dihydroxybenzene, a 2,6-dihydroxy-4-methoxybenzene and a 3-hydroxycyclohexan-2,6-dione. Three additional 2,6-dihydroxybenzenes are substituted by hexadecanoyl, hexadec-4Z-enoyl and 8-hydroxyoctadec-4Z-enoyl groups. 相似文献
948.
The carbon partitioning of the epipelic diatom Cylindrotheca closterium (Ehrenberg) Reiman and Lewin isolated from the Adriatic Sea was studied in the laboratory under varying scenarios of nutrient limitation. Total number of cells, photosynthesis measured at 695 μmol photons·m − 2 ·s − 1 irradiance (P695- μ mol ), chlorophyll ( a + c ) content, respiration, extracellular polymeric substances (EPS), total particulate carbohydrate (TPC), and dissolved carbohydrate were evaluated under nitrogen and phosphorus deficiencies in culture. The highest total number of cells was found in the control, whereas the nitrogen-limited treatment showed the lowest value. During the transition phase of growth, photosynthesis in the nitrogen-limited treatment was 3-fold lower than in the phosphorus-limited treatment and 4-fold lower than in the control. Differences in respiration rates and chlorophyll ( a + c ) content were even more marked. Dissolved carbohydrate remained the same in all the treatments, whereas during the transition and stationary phase, EPS presented the highest values under phosphorus limitation and the lowest in the control treatment. The production of EPS was closely linked to the periods of carbon assimilation (transition phase) in the nutrient depleted treatments, especially in the phosphorus-limited treatment. These results point out the relevance of the nutrient imbalance (nitrogen or phosphorus) in the production of EPS by the benthic or resuspended diatoms and suggest that these diatoms play an important role in nutrient-unbalanced systems like sediments or marine snow. 相似文献
949.
Influence of caffeine on 3,4‐methylenedioxymethamphetamine‐induced dopaminergic neuron degeneration and neuroinflammation is age‐dependent
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950.
V. I. Loginov A. M. Burdennyy I. V. Pronina V. V. Khokonova S. V. Kurevljov T. P. Kazubskaya N. E. Kushlinskii E. A. Braga 《Molecular Biology》2016,50(5):705-709
MicroRNAs play an important role in the regulation of expression of many genes involved in cancer pathogenesis. One of the causes of miRNA level deregulation in tumors is the methylation of CpG islands in the promoter regions of the genes that encode them. Hypermethylation may lead to the suppression of miRNA gene expression and, as a consequence, to a decrease in their inhibitory effect on target gene mRNAs. A search for new miRNA genes hypermethylated in breast cancer has been carried out in the present study. The methylation of five miRNA genes associated with breast cancer (miR-132, miR-1258, miR-107, miR-130b, miR-137) has been as studied using a representative set of 41 breast cancer samples by methylation-specific PCR. Three new genes, MIR-132, MIR-137 and MIR-1258, with a high frequency of hypermethylation (41, 37 and 34%, respectively) have been identified in breast cancer. The methylation of these genes in the breast tissues of ten donors without cancer pathology in anamnesis was only found in single cases. These results enable the involvement of three miRNAs (miR-132, miR-137, miR-1258) and the methylation of the genes that encode them in the pathogenesis of breast cancer to be suggested. 相似文献