共查询到20条相似文献,搜索用时 31 毫秒
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In Synechococcus sp. strain PCC 7942 the D1 protein of Photosystem II is encoded by a multigene family; psbAI encodes Form I of D1 whereas both psbAII and psbAIII encode Form II. The psbA genes are differentially regulated in response to changes in light intensity, such that psbAI expression and Form I predominate at standard light intensity, whereas psbAII and psbAIII are induced at high light intensity, causing insertion of Form II into the thylakoids. The present study addressed whether high-light induced Form II is important for Synechococcus cells during adaptation to high light intensity. Wild-type Synechococcus, and mutants which produce only Form I (R2S2C3) or only Form II (R2K1), were co-cultured at standard light (130 E · m–2 · s–1) and then shifted to high light (750 E·m–2·s–1). Measurement of the proportion of each cell type at various time intervals revealed that the growth of R2S2C3, which has psbAII and psbAIII inactive, and thus lacks Form II, is transiently impaired upon shift to high light. Both mutants R2S2C3 and R2K1 maintained normal levels of psbA messages and D1 protein under standard and high light through an unknown mechanism that compensates for the inactive psbA genes. Thus, the impairment of R2S2C3 at high light is not due to a deficiency of D1 protein, but results from lack of Form II. We discounted the influence of possible secondary mutations by re-creating the psbA-inactivated mutants and testing the newly isolated strains. We conclude that Form II of D1 is intrinsically important for Synechococcus cells during a critical transition period after exposure to high light intensities. 相似文献
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Koichi Abe Kotone Miyake Mayumi Nakamura Katsuhiro Kojima Stefano Ferri Kazunori Ikebukuro Koji Sode 《Microbial biotechnology》2014,7(2):177-183
In order to construct a green‐light‐regulated gene expression system for cyanobacteria, we characterized a green‐light sensing system derived from Synechocystis sp. PCC6803, consisting of the green‐light sensing histidine kinase CcaS, the cognate response regulator CcaR, and the promoter of cpcG2 (PcpcG2). CcaS and CcaR act as a genetic controller and activate gene expression from PcpcG2 with green‐light illumination. The green‐light induction level of the native PcpcG2 was investigated using GFPuv as a reporter gene inserted in a broad‐host‐range vector. A clear induction of protein expression from native PcpcG2 under green‐light illumination was observed; however, the expression level was very low compared with Ptrc, which was reported to act as a constitutive promoter in cyanobacteria. Therefore, a Shine‐Dalgarno‐like sequence derived from the cpcB gene was inserted in the 5′ untranslated region of the cpcG2 gene, and the expression level of CcaR was increased. Thus, constructed engineered green‐light sensing system resulted in about 40‐fold higher protein expression than with the wild‐type promoter with a high ON/OFF ratio under green‐light illumination. The engineered green‐light gene expression system would be a useful genetic tool for controlling gene expression in the emergent cyanobacterial bioprocesses. 相似文献
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H. Boetti L. Chevalier L. A. Denmat D. Thomas B. Thomasset 《Biotechnology and bioengineering》1999,64(1):1-13
In this study, the efficiency of inducible promoters to switch on gene expression in the presence of inducer or to switch it off in its absence was evaluated in tobacco cell suspensions transformed with the gus gene coding sequence. Either plant (pats1A, pSalT, pIn2‐2) or microbial (pMre, pTet) inducible promoters were used to drive gus expression. The inducers were light, abscisic acid, 2‐CBSU, CuSO4, tetracycline, respectively. For each construct (inducible promoter‐gus coding sequence), the optimal induction conditions were determined (inducer concentration, induction time, and age of cells in culture cycle before induction). The efficiency of the inducible promoter was then evaluated under optimal induction conditions. GUS‐expression levels obtained under non‐inducing and inducing conditons were systematically compared. Thirty or forty percent of the clones transformed with the pSalT‐gus or pTet‐gus construct, respectively, showed high induction rates (>1000) and GUS activities of the same order as those obtained with a constitutive system. However, basal GUS levels were always high for the pTet‐gus cell lines. Seventy or eighty‐five percent of the cell lines transformed with the pMre‐gus or pln2‐2‐gus construct, respectively, had induction rates of 1.5 to 1000. The pats1A‐gus construct gave very low induction rates—55% of cell lines had induction rates less than 1.5. Only the pSalt‐gus construct gave both the highest induction rates and basal GUS‐levels equivalent to the endogenous GUS background. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 64: 1–13, 1999. 相似文献
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Symbiodinium transcriptome and global responses of cells to immediate changes in light intensity when grown under autotrophic or mixotrophic conditions 下载免费PDF全文
Tingting Xiang William Nelson Jesse Rodriguez Dimitri Tolleter Arthur R. Grossman 《The Plant journal : for cell and molecular biology》2015,82(1):67-80
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N. V. Kudryakova V. V. Kusnetsov V. Y. Shtratnikova Olga N. Kulaeva 《Plant Growth Regulation》2008,56(1):21-30
ARR5-gene expression was studied in the course of natural leaf senescence and detached leaf senescence in the dark using Arabidopsis thaliana plants transformed with
the P
ARR5
-GUS gene construct. GUS-activity was measured as a marker of ARR5-gene expression. Chlorophyll and total protein amounts were also estimated to evaluate leaf senescence. Natural leaf senescence
was accompanied by the progressive decline in the GUS-activity in leaves of the 2nd and 3rd nodes studied, and this shift
of GUS-activity was more pronounced than the loss of chlorophyll content. The ability of the ARR5-gene promoter to respond to cytokinin was not eliminated during natural leaf senescence, as was demonstrated by a cytokinin-induced
increase in GUS activity in leaves after their detachment and incubation on benzyladenine
(BA, 5 × 10−6 M) in the dark. Leaf senescence in the dark was associated with the further decrease in the GUS-activity. The ARR5-gene promoter response
to cytokinin was enhanced with the increase of the age of plants, taken as a source of leaves for cytokinin treatments. Hence,
although the expression of the ARR5 gene reduces during natural and dark/detached leaf senescence, the ARR5-gene sensitivity to cytokinin was maintained in both cases and even increased with the leaf age. This data suggest that the
ARR5 gene, which belongs to the type-A negative regulators of plant response to cytokinin, could be a feedback regulator able
to prevent retardation by cytokinin of leaf senescence when it is important for plant life. Growth regulators either reduced
ARR5 gene response to cytokinin during senescence of mature detached leaves
in the dark (SA, meJA, ABA, SP) or increased it (IAA), thus modifying the resulting rate of its expression. 相似文献
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M. N. Danilova N. V. Kudryakova N. K. Zubkova V. V. Kusnetsov O. N. Kulaeva 《Russian Journal of Plant Physiology》2012,59(3):291-298
The expression regulation by cytokinin of genetic constructs P
AHK2
-GUS, P
AHK3
-GUS, and P
AHK4
-GUS in transgenic Arabidopsis thaliana (L.) Heynh plants bearing the gene encoding β-glucuronidase (GUS) under the control of the promoter of one of three genes encoding histidine protein kinases, which are membrane receptors
of cytokinin was studied. In 4–5-day-old etiolated A. thaliana seedlings, treatment with cytokinin resulted in the strongest expression activation of the constructs P
AHK2
-GUS and P
AHK3
-GUS. The same constructs were activated by cytokinin also at the seedling transit from scoto- to photomorphogenesis. Long-term
seedling growing in darkness on medium containing cytokinin resulted in the substantial promoter activation of the gene encoding
the histidine kinase AHK2. In the leaves of three-week-old plants with actively functioning chloroplasts, treatment with cytokinin
mainly stimulated expression of the construct P
AHK3
-GUS. In detached senescing leaves, treatment with cytokinin retarded the loss of chlorophyll but did not affect significantly
GUS activity under both light and darkness conditions in either of tested lines containing GUS gene under the control of promoters of histidine kinase genes. At the same time, cytokinin activated the promoter of the
gene of primary response to cytokinin in the construct P
ARR5
-GUS. Thus, in the studied test-system, treatment with cytokinin of A. thaliana plant grown in darkness or in the light affected differently the expression of histidine kinase genes in dependence of plant
age, conditions of plant cultivation, and plant physiological state. 相似文献
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Schmitz Oliver Tsinoremas Nicholas F. Schaefer Michael R. Anandan Shivanthi Golden Susan S. 《Photosynthesis research》1999,62(2):261-271