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排序方式: 共有105条查询结果,搜索用时 125 毫秒
11.
Sandip Mukhopadhyay Serge Overney Serge Yelle Yves Desjardins 《Journal of plant biochemistry and biotechnology.》2002,11(1):57-60
An effective method for consistent regeneration of transgenic asparagus (Asparagus officinalis L) plants from electroporated protoplasts is described. Transgenic plants containing β-glucuronidase (GUS) and neomycin-phosphotransferase (NPT II) genes were obtained by electroporating callus-derived protoplasts of Asparagus officinalis L. Embryogenic callus tissue and plants from four kanamycin resistant lines expressed P-glucuronidase activity, as revealed by histological staining. The amplification of genomic DNA by polymerase chain reaction revealed the presence of both GUS and NPT II genes in transformed callus tissue and plants. Southern hybridization confirmed the integration of these genes into the asparagus genome. 相似文献
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A promoter fusion (Sh35) combining upstream regulatory regions from the maize Sh1 promoter with a truncated 35S promoter, Δ9035 (–90 to +8) has been compared with the original Sh1 promoter for its capacity to promote expression of the β-glucuronidase (GUS) gene in stably transformed tomato plants. For both promoters, very faint GUS expression was detected
in the vegetative tissues, and no expression was detected in the fruit pericarp tissues. However, in the seed, Sh1 promoted low GUS expression but Sh35 directed 25-fold higher GUS expression. For both constructs, the profile of GUS expression
was similar to that of endogenous sucrose synthase activity, but maximal GUS activity was reached 15 days after the peak of
sucrose synthase activity.
Received: 20 October 1998 / Revision received: 1 December 1998 / Accepted: 14 December 1998 相似文献
15.
Starch synthesis in tomato remains constant throughout fruit development and is dependent on sucrose supply and sucrose synthase activity 总被引:6,自引:3,他引:3
N'tchobo H; Dali N; Nguyen-Quoc B; Foyer C; Yelle S 《Journal of experimental botany》1999,50(338):1457-1463
Studies designed to investigate the cellular pathway of phloem unloading
were conducted on two tomato lines with either high or low fruit invertase
activities. Experiments were based on determination of the degree to which
3H label from
[3H]-(fructosyl)-sucrose was randomized between
fructose and glucose following exposure of excised fruit to a pulse of
labelled sucrose delivered through pedicels. Fruit from the low invertase
line harvested 10, 20 and 40 d after anthesis had similar sucrose uptake
kinetics to the high invertase line. A positive correlation was found
between sucrose synthase activity and sucrose uptake in both low and high
invertase lines. In contrast, no correlation was observed between acid or
neutral invertase activities and sucrose uptake. Within the putative
apoplasmic sap collected from fruit, label in
[3H]-(fructosyl)-sucrose was randomized between the
free hexoses and sucrose hexose moieties. Label asymmetry was retained in
sucrose on arrival within the tissues. Randomization patterns were similar
in both the low and high acid invertase lines. These data support the view
that sucrose imported into the fruit was not exposed to extracellular
hydrolysis. This suggests that movement from the phloem is likely to occur
predominantly through a symplastic pathway. About 25% of the sucrose taken
up by the fruit was converted into starch regardless of fruit age,
suggesting that starch turnover remains constant throughout fruit
development and that starch synthesis was dependent on sucrose
supply. 相似文献
16.
Evidence for cleavage of lignin by a brown rot basidiomycete 总被引:5,自引:0,他引:5
Biodegradation by brown-rot fungi is quantitatively one of the most important fates of lignocellulose in nature. It has long been thought that these basidiomycetes do not degrade lignin significantly, and that their activities on this abundant aromatic biopolymer are limited to minor oxidative modifications. Here we have applied a new technique for the complete solubilization of lignocellulose to show, by one-bond 1 H-13 C correlation nuclear magnetic resonance spectroscopy, that brown rot of spruce wood by Gloeophyllum trabeum resulted in a marked, non-selective depletion of all intermonomer side-chain linkages in the lignin. The resulting polymer retained most of its original aromatic residues and was probably interconnected by new linkages that lack hydrogens and are consequently invisible in one-bond 1 H-13 C correlation spectra. Additional work is needed to characterize these linkages, but it is already clear that the aromatic polymer remaining after extensive brown rot is no longer recognizable as lignin. 相似文献
17.
There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs. 相似文献
18.
Richard GH Immink Isabella AN Tonaco Stefan de Folter Anna Shchennikova Aalt DJ van Dijk Jacqueline Busscher-Lange Jan W Borst Gerco C Angenent 《Genome biology》2009,10(2):R24-16
Background
Plant MADS box proteins play important roles in a plethora of developmental processes. In order to regulate specific sets of target genes, MADS box proteins dimerize and are thought to assemble into multimeric complexes. In this study a large-scale yeast three-hybrid screen is utilized to provide insight into the higher-order complex formation capacity of the Arabidopsis MADS box family. SEPALLATA3 (SEP3) has been shown to mediate complex formation and, therefore, special attention is paid to this factor in this study. 相似文献19.
Insertion of foreign DNA into the unique HindIII site of the high copy number plasmid pAT153 reduces but does not completely abolish the resistance of Escherichia coli HB101 cells to tetracycline. Recombinant DNA-containing colonies could then be phenotypically differentiated from non-recombinant ones by their smaller size on nutrient agar plates with ampicillin and tetracycline at a final concentration of 50 and 4 micrograms/ml, respectively. A wide variety of human cytomegalovirus DNA fragments have been found in pAT153 molecules propagated by the ampicillin-resistant tetracycline-sensitive bacteria selected. 相似文献
20.
The ITS sequences of Acropora spp. are the shortest so far identified in
any metazoan and are among the shortest seen in eukaryotes; ITS1 was 70-80
bases, and ITS2 was 100-112 bases. The ITS sequences were also highly
variable, but base composition and secondary structure prediction indicate
that divergent sequence variants are unlikely to be pseudogenes. The
pattern of variation was unusual in several other respects: (1) two
distinct ITS2 types were detected in both A. hyacinthus and A. cytherea,
species known to hybridize in vitro with high success rates, and a putative
intermediate ITS2 form was also detected in A. cytherea; (2) A. valida was
found to contain highly (29%) diverged ITS1 variants; and (3) A.
longicyathus contained two distinct 5.8S rDNA types. These data are
consistent with a reticulate evolutionary history for the genus Acropora.
相似文献