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排序方式: 共有283条查询结果,搜索用时 15 毫秒
191.
Merlo Pich M Castagnoli A Biondi A Bernacchia A Tazzari PL D'Aurelio M Parenti Castelli G Formiggini G Conte R Bovina C Lenaz G 《Free radical research》2002,36(4):429-436
The conditions under which Coenzyme Q (CoQ) may protect platelet mitochondrial function of transfusional buffy coats from aging and from induced oxidative stress were investigated. The Pasteur effect, i.e. the enhancement of lactate production after inhibition of mitochondrial respiratory chain, was exploited as a marker of mitochondrial function as it allows to calculate the ratio of mitochondrial ATP to glycolytic ATP. Reduced CoQ 10 improves platelet mitochondrial function of transfusional buffy coats and protects the cells from induced oxidative stress. Oxidized CoQ is usually less effective, despite the presence, shown for the first time in this study, of quinone reductase activities in the platelet plasma membranes. The addition of a CoQ reducing system to platelets is effective in enhancing the protection of platelet mitochondrial function from the oxidative stress. The results support on one hand a possibility of protection of mitochondrial function in aging by exogenous CoQ intake, on the other a possible application in protection of transfusional buffy coats from storage conditions and oxidative deterioration. 相似文献
192.
We coupled Tn5 mutagenesis with a competition assay to isolate mutants of Rhizobium fredii USDA 257 that are defective in competition for nodulation of soybeans. Two mutants with single Tn5 inserts in the chromosome showed reduced competitiveness in vermiculite but were identical to the wild-type strain in symbiotic properties when inoculated alone. Recombination of Tn5 and flanking genomic regions cloned from the mutants into the parent strain showed that Tn5 was responsible for the mutant phenotype. 相似文献
193.
Silvio Roncella Stefania Laurent Vincenzo Fontana Paola Ferro Maria Cristiana Franceschini Sandra Salvi Serena Varesano Simona Boccardo Antonella Vigani Anna Morabito Pier Aldo Canessa Ugo Giannoni Ilan Rosenberg Alessandro Valentino Franco Fedeli Domenico Franco Merlo Marcello Ceppi Salvatore Riggio Massimo Romani Daniele Saverino Alessandro Poggi Maria Pia Pistillo 《Cancer immunology, immunotherapy : CII》2016,65(8):909-917
194.
Howe GT; Bucciaglia PA; Hackett WP; Furnier GR; Cordonnier-Pratt MM; Gardner G 《Molecular biology and evolution》1998,15(2):160-175
The phytochrome photoreceptors play important roles in the photoperiodic
control of vegetative bud set, growth cessation, dormancy induction, and
cold-hardiness in trees. Interestingly, ecotypic differences in
photoperiodic responses are observed in many temperate- zone tree species.
Northern and southern ecotypes of black cottonwood (Populus trichocarpa
Torr. & Gray), for example, exhibit marked differences in the timing of
short-day-induced bud set and growth cessation, and these responses are
controlled by phytochrome. Therefore, as a first step toward determining
the molecular genetic basis of photoperiodic ecotypes in trees, we
characterized the phytochrome gene (PHY) family in black cottonwood. We
recovered fragments of one PHYA and two PHYB using PCR-based cloning and by
screening a genomic library. Results from Southern analyses confirmed that
black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily
designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from
black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum)
suggest that the PHYB/D duplications in these species occurred
independently. When Southern blots were probed with PHYC, PHYE, and PHYE
heterologous probes, the strongest bands that we detected were those of
black cottonwood PHYA and/or PHYB. These results suggest that black
cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black
cottonwood could contain additional PHY that are distantly related to known
angiosperm PHY, our results imply that the PHY family of black cottonwood
is less complex than that of other well-characterized dicot species such as
Arabidopsis and tomato. Based on Southern analyses of five black cottonwood
genotypes representing three photoperiodic ecotypes, substantial
polymorphism was detected for at least one of the PHYB loci but not for the
PHYA locus. The novel character of the PHY family in black cottonwood, as
well as the differences in polymorphism we observed between the PHYA and
PHYB subfamilies, indicates that a number of fundamental macro- and
microevolutionary questions remain to be answered about the PHY family in
dicots.
相似文献
195.
The developmental profile of the activities of some enzymes involved in malate metabolism, namely phosphoenolpyruvate carboxylase (PEPC; EC 4. 1. 1. 31), NAD+ -linked (EC 1. 1. 1. 37) and NADP+ -linked (EC 1. 1. 1. 82) malate dehydrosenase (MDH), NAD+ linked (EC 1. 1. 1. 39) and NADP+ -linked (EC 1. 1. 1. 40) malic enzyme (ME), has been determined in leaves of peach [ Prunus persica (L.) Batsch cv. Maycrest], a woody C3 species. In order to study the role of these enzymes, their activities were related to developmental changes of photosynthesis, respiration, and capacity for N assimilation. Activities of PEPC, NAD(P)+ -MDH and NADP+ -ME were high in young expanding leaves and decreased 2- to 3-fold in mature ones, suggesting that such enzymes play some role during the early stages of leaf expansion. In leaves of peach, such a role did not seem to be linked to C3 photosynthesis or nitrate assimilation, in that photosynthetic O2 evolution and activities of nitrate reductase (EC 1. 6. 6. 1) and glutamine synthetase (EC 6. 3. 1. 2) increased during leaf development. In contrast, leaf respiration strongly decreased with increasing leaf age. We suggest that in expanding leaves of this woody species the enzymes associated with malate metabolism have anaplerotic functions, and that PEPC may also contribute to the recapture of respiratory CO2 . 相似文献
196.
D. Mercanti A. Angelini MT. Ciotti ML. Eboli C. Galli L. Battistini D. Merlo P. Calissano 《Cytotechnology》1993,11(Z1):S117-S119
The neurite outgrowth and adhesion complex (NOAC), isolated from rabbit sera has been dissociated in its major components by reverse-phase chromatography in HPLC by using a C18 column. SDS-PAGE analisys of the active fractions revealed the presence of three major bands of approximately 100, 70 and 50 kDa. Studies on the biological activity of NOAC were carried out on rat cerebellar granule cells. NOAC-cultured cells exhibit a marked resistance to excitotoxic stimuli carried by glutamate. 相似文献
197.
Bacteriophage Typing as an Epidemiological Tool for Urinary Escherichia coli 总被引:2,自引:1,他引:1
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Phage typing was used to identify strains of Escherichia coli isolated from urinary and nonurinary sources. When eight phages isolated in Pennsylvania were used to type 717 cultures from Missouri, 50.3% of 624 urinary isolates and 34.4% of 93 nonurinary isolates were typable. Strains from nonurinary sources were not found commonly in urine. When five additional phages isolated in Missouri were added to the original set of eight phages, 80.4% of 331 urinary isolates were typable. When this set of phages was used to type 552 urinary cultures isolated in California, Minnesota, Ohio, Pennsylvania, Virginia, and West Virginia, 82.0% of the cultures were typable. Some common phage types were found in high incidence among cultures from the different regions. No correlation was found between phage type and the pattern of resistance to antibiotics. Phage typing data were presented also on the number of strains in individual urine specimens and the recurrences of strains in patients with chronic bacteriuria. Of 97 fecal isolates, 75.2% of the cultures were typable, and the most common phage type was observed in high incidence among the urinary isolates from this region. When 75 cultures from nine other genera of enteric bacteria were typed, only the shigellae were lysed. In view of the information obtained by phage typing and the ease and speed with which it can be done, it is suggested that phage typing be considered a new tool in epidemiological studies of urinary tract infections by E. coli. 相似文献
198.
Funmei Yang Donald J. Merlo Milton P. Gordon Eugene W. Nester 《Molecular & general genetics : MGG》1980,179(1):223-226
Summary Tabac anergié tissue has been used by many investigators as a habituated tobacco cell line. In this study, we have found sequences which are homologous to approximately 9 megadaltons of an Agrobacterium octopine-type plasmid in DNA isolated from Tabac anergié tissue. These T-DNA sequences were shown to be the same core DNA sequences found to be present in several other unorganized tumor lines which have been studied in our laboratory. The T-DNA was also shown to be integrated into plant DNA. Thus, the Tabac anergié tissue is a crown gall tumor induced by a strain of Agrobacterium tumefaciens containing an octopinetype plasmid. These results indicated that the plants regenerated from 40 clones of the Tabac anergié line by Sacristán and Melchers (1977) were actually reverted plants obtained from an unorganized crown gall tumor, kept in culture for more than 25 years. It is necessary to re-evaluate observations and conclusions which have been based upon Tabac anergié being a habituated tissue. 相似文献
199.
Changes in carbohydrate and enzyme levels during development of leaves of Prunus persica, a sorbitol synthesizing species 总被引:9,自引:0,他引:9
Carbohydrate levels and activities of enzymes associated with starch, sucrose and sorbitol metabolism were assayed in leaves of peach [ Prunus persica (L.) Batsch cv. Redhaven] of different ages, in order to examine developmental changes in leaf carbohydrate metabolism. Dry matter, soluble protein, chlorophyll and the activities of key enzymes of the reductive pentose phosphate pathway increased during leaf development. The levels of leaf carbohydrates, especially sorbitol and starch, also increased. Changes of starch levels were related to increases in the activities of enzymes associated to starch metabolism, such as ADPglucose-pyrophosphorylase (E.C. 2.7.7.27) and amylase (E.C. 3.2.1.1. plus E.C. 3.2.1.2). The activities of enzymes involved in sucrose and sorbitol degradation decreased during leaf development, whereas the activities of aldose-6-phosphate reductase (E.C. 1.1.1.200) and cytosolic fructase-1,6-bisphosphatase (E.C. 3.1.3.11) increased. In contrast, the activity of sucrose-phosphate synthase (E.C. 2.4.1.14) did not vary in a significant manner. The results suggest that the ability to synthesize and utilize both sucrose and sorbitol changes as peach leaves mature, and also that there are differences in metabolism of these two transport sugars during leaf development. 相似文献
200.
T Venesio D Taverna N E Hynes R Deed D MacAllan F Ciardiello E M Valverius D S Salomon R Callahan G Merlo 《Cell growth & differentiation》1992,3(1):63-71
We have investigated the effect of basic fibroblast growth factor (bFGF) and the related int-2 gene on the growth, transformation, and differentiation of HC11 mouse mammary epithelial cells. We show that in HC11 cells infected with int-2 retroviral expression vectors, the int-2 protein can function as a bFGF-like growth factor in stimulating: (a) HC11 cell proliferation in monolayer, (b) anchorage-independent growth in soft agar, and (c) soft agar growth of the bFGF-responsive SW13 tumor cell line. These effects are observed irrespective of whether the int-2 protein is expressed in its wild-type form or is linked to a signal peptide. A candidate bFGF receptor, which is the product of the flg gene and which may recognize the int-2 protein, is expressed at high levels in HC11 cells. Following epidermal growth factor or bFGF priming and subsequent treatment with lactogenic hormones, all of the int-2 infected and the parental HC11 cells synthesize similar levels of beta-casein. However, the autocrine expression of int-2 in HC11 cells abrogates their requirement for either exogenous epidermal growth factor or bFGF priming. These data suggest that, in HC11 cells, the growth factor activity of the int-2 gene is indistinguishable from that of bFGF and does not interfere with the mammary cell differentiation program associated with lactogenesis. 相似文献