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1.
Weimin Ma Lanzhen Wei Quanxi Wang Dingji Shi Haibao Chen 《Journal of applied phycology》2007,19(3):207-213
Non-regulated enzymes in the Calvin cycle are generally presumed to be less important for the regulation of photosynthetic
yield. Here, to investigate the relationship between the activity of non-regulated enzymes and photosynthetic yield, two non-regulated
enzymes in the Calvin cycle—a rice cytosolic fructose-1,6-bisphosphate aldolase (FBA) and a spinach chloroplast triosephosphate
isomerase (TPI)—were cloned and co-expressed in cells of the cyanobacterium Anabaena sp. strain PCC 7120. The activity of FBA and TPI and the photosynthetic yield reflected by photosynthetic O2 evolution and cell dry weight were measured and compared between wild-type and transgenic cells. Our results demonstrated
that the activity of FBA and TPI were increased in transgenic cells relative to wild-type cells, and that activity was further
increased in a transgenic strain harboring two sets of FBA-TPI tandem genes relative to cells containing one copy of the FBA-TPI
tandem gene. The increased activity of FBA and TPI in Anabaena sp. strain PCC 7120 increased photosynthetic yield, with increased activity levels correlating closely with the degree of
changes in photosynthetic yield. This implies that the photosynthetic yield is limited by the activity of the non-regulated
enzymes FBA and TPI, and that the endogenous activity of non-regulated enzymes is not sufficient to increase photosynthetic
yield. We discuss the various roles of FBA and TPI, and regulated and non-regulated enzymes, in modulating photosynthetic
yield.
W. Ma and L. Wei contributed equally to this work. 相似文献
2.
Weimin Ma Lanzhen Wei Quanxi Wang Dingji Shi Haibao Chen 《Journal of applied phycology》2008,20(4):437-443
The regulation of photosynthetic yield at the genetic level has largely focused on manipulation of the catalytic enzymes in
the Calvin cycle by genetic engineering. In order to investigate the contribution of increased enzymatic activity in the Calvin
cycle on photosynthetic yield, the rice fructose-1,6-bisphosphate aldolase (FBA), spinach triosephosphate isomerase (TPI)
and wheat fructose-1,6-bisphosphatase (FBPase) genes were cloned in tandem and co-overexpressed in cyanobacterium Anabaena sp. strain PCC 7120 cells. The enzymatic activities of FBA, TPI and FBPase, as well as sedoheptulose-1,7-bisphosphatase (SBPase),
were remarkably increased in transgenic cells relative to the wild-type. The photosynthetic yield, as reflected by photosynthetic
O2 evolution and dry cellular weight, was also markedly increased in transgenic cells versus wide-type cells. The activity of
SBPase is considered the most important factor for ribulose-1,5-bisphosphate (RuBP) regeneration in the Calvin cycle, and
increased activity of TPI alone in transgenic cells does not stimulate photosynthetic yield. Thus, the increased activity
of FBA and FBPase, but not TPI, significantly improved photosynthetic yield in transgenic cells by stimulating SBPase activity
and consequently accelerating the RuBP regeneration rate. 相似文献
3.
Weimin Ma Lanzhen Wei Zongjuan Long Liping Chen Quanxi Wang 《Acta Physiologiae Plantarum》2008,30(6):897-904
The goal of this study was to investigate the contribution of increased activity of individual non-regulated enzymes in the
Calvin cycle to improve photosynthetic yield. Two non-regulated enzymes, rice fructose-1,6-bisphosphate aldolase (FBA) and
spinach triosephosphate isomerase (TPI), were individually cloned and overexpressed in the cyanobacterium Anabaena sp. strain PCC 7120 cells. The enzyme activity and the photosynthetic yield, as reflected by the cell growth rate, photosynthetic
oxygen evolution and dry cellular weight, were measured and compared between the wild-type and transgenic cells harboring
either FBA or TPI. Though the activity of these two individual non-regulated enzymes was similarly increased in the corresponding
transgenic cells, the contributions of each enzyme on the amount of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco),
reflected by the levels of Rubisco large subunit, and the photosynthetic yield were different. Transgenic cells, carrying
FBA, showed an evident increase in Rubisco amount and photosynthetic yield, while there was no increase in cells harboring
TPI. This indicates that the contributions of non-regulated enzymes in the Calvin cycle on photosynthetic yield differed and
firstly reveals that increased activity of only a single non-regulated enzyme in transgenic cells markedly improves the photosynthetic
yield via stimulating the amount of Rubisco and consequently accelerating the ribulose-1,5-bisphosphate (RuBP) regeneration
rate. 相似文献
4.
Susana Enríquez Carlos M. Duarte Kaj Sand-Jensen Søren Laurentius Nielsen 《Oecologia》1996,108(2):197-206
5.
6.
O. N. Rozova V. N. Khmelenina I. I. Mustakhimov A. S. Reshetnikov Y. A. Trotsenko 《Biochemistry. Biokhimii?a》2010,75(7):892-898
The gene fba from the thermotolerant obligate methanotroph Methylococcus capsulatus Bath was cloned and expressed in Escherichia coli BL21(DE3). The fructose-1,6-bisphosphate aldolase (FBA) carrying six His on the C-end was purified by affinity metal chelating
chromatography. The Mc. capsulatus FBA is a hexameric enzyme (240 kDa) that is activated by Co2+ and inhibited by EDTA. The enzyme displays low K
m to fructose-1,6-bisphosphate (FBP) and higher K
m to the substrates of aldol condensation, dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. The FBA also catalyzes
sedoheptulose-1,7-bisphosphate cleavage. The presence of Co2+ in the reaction mixture changes the kinetics of FBP hydrolysis and is accompanied by inhibition of the reaction by 2 mM FBP.
Phylogenetically, the Mc. capsulatus enzyme belongs to the type B of class II FBAs showing high identity of translated amino acid sequence with FBAs from autotrophic
bacteria. The role of the FBA in metabolism of Mc. capsulatus Bath, which realizes simultaneously three C1 assimilating pathways (the ribulose monophosphate, the ribulose bisphosphate, and the serine cycles), is discussed. 相似文献
7.
8.
Susan Puckett Carolina Trujillo Hyungjin Eoh Joeli Marrero John Spencer Mary Jackson Dirk Schnappinger Kyu Rhee Sabine Ehrt 《PLoS pathogens》2014,10(5)
Metabolic pathways used by Mycobacterium tuberculosis (Mtb) to establish and maintain infections are important for our understanding of pathogenesis and the development of new chemotherapies. To investigate the role of fructose-1,6-bisphosphate aldolase (FBA), we engineered an Mtb strain in which FBA levels were regulated by anhydrotetracycline. Depletion of FBA resulted in clearance of Mtb in both the acute and chronic phases of infection in vivo, and loss of viability in vitro when cultured on single carbon sources. Consistent with prior reports of Mtb''s ability to co-catabolize multiple carbon sources, this in vitro essentiality could be overcome when cultured on mixtures of glycolytic and gluconeogenic carbon sources, enabling generation of an fba knockout (Δfba). In vitro studies of Δfba however revealed that lack of FBA could only be compensated for by a specific balance of glucose and butyrate in which growth and metabolism of butyrate were determined by Mtb''s ability to co-catabolize glucose. These data thus not only evaluate FBA as a potential drug target in both replicating and persistent Mtb, but also expand our understanding of the multiplicity of in vitro conditions that define the essentiality of Mtb''s FBA in vivo. 相似文献
9.
William Martin Abdel-Zaher Mustafa Katrin Henze Claus Schnarrenberger 《Plant molecular biology》1996,32(3):485-491
Full-size cDNAs encoding the precursors of chloroplast fructose-1,6-bisphosphatase (FBP), sedoheptulose-1,7-bisphosphatase (SBP), and the small subunit of Rubisco (RbcS) from spinach were cloned. These cDNAs complete the set of homologous probes for all nuclear-encoded enzymes of the Calvin cycle from spinach (Spinacia oleracea L.). FBP enzymes not only of higher plants but also of non-photosynthetic eukaryotes are found to be unexpectedly similar to eubacterial homologues, suggesting a eubacterial origin of these eukaryotic nuclear genes. Chloroplast and cytosolic FBP isoenzymes of higher plants arose through a gene duplication event which occurred early in eukaryotic evolution. Both FBP and SBP of higher plant chloroplasts have acquired substrate specificity, i.e. have undergone functional specialization since their divergence from bifunctional FBP/SBP enzymes of free-living eubacteria.Abbreviations FBP
fructose-1,6-bisphosphatase
- SBP
sedoheptulose-1,7-bisphosphatase
- FBA
fructose-1,6-bisphosphate aldolase 相似文献
10.
Daniel A.O. Fernandes 《Journal of experimental marine biology and ecology》2011,407(2):370-376
Aggregation of embryos in clutches that lack internal circulation can increase the risk of hypoxia by limiting gas exchange. As a result, limits on oxygen solubility and diffusion in water can constrain the size and embryo concentration of aquatic egg clutches. Hypoxia in egg masses can slow embryo development, increase mortality, and reduce size at hatching. The risk of hypoxia for embryos, however, can be reduced by association with photosynthetic organisms. We examined whether embryo development in egg ribbons of the cephalaspidean mollusk Haminoea vesicula is significantly influenced by oviposition on eelgrass (Zostera marina). Association with the photosynthetic substrate had marked effects on development relative to association with non-photosynthetic substrates, and the direction of these effects was mediated by light conditions. Under intermediate and high light levels, association with eelgrass accelerated embryo development, while under dim light, the presence of the macrophyte increased development rate and reduced hatchling shell size. Benefits of association with eelgrass at higher light levels likely result from oxygen production by eelgrass photosynthesis, while we attribute costs under low light to oxygen depletion by eelgrass respiration. Association with Z. marina also limited microphyte growth in egg ribbons of H. vesicula. In the field, measurements of light attenuation within an eelgrass bed showed that conditions under which benefits accrue to embryos are ecologically relevant and correspond to spatial patterns of oviposition on eelgrass in the field. The choice of a photosynthetic oviposition substrate under appropriate light conditions can improve embryo fitness by accelerating embryo development without compromising hatchling size and by reducing the potential for excessive and harmful fouling by microphytes. 相似文献
11.
The sequence and expression of mRNA homologous to a cDNA encoding a non-photosynthetic ferredoxin (Fd1) from Citrus fruit was investigated. The non-photosynthetic nature of this ferredoxin was deduced from: (1) amino acid sequence alignments showing better scores with non-photosynthetic than with photosynthetic ferredoxins, (2) higher expression in tissues containing plastids other than chloroplast such as petals, young fruits, roots and peel of fully coloured fruits, and (3) the absence of light-dark regulation characteristic of photosynthetic ferredoxins. In a phylogenetic tree constructed with higher-plant ferredoxins, Citrus fruit ferredoxin clustered together with root ferredoxins and separated from the photosynthetic ferredoxins. Non photosynthetic (root and fruit) ferredoxins, but not the photosynthetic ferredoxins, have their closest homologs in cyanobacteria. Analysis of ferredoxin genomic organization suggested that non-photosynthetic ferredoxins exist in Citrus as a small gene family. Expression of Fd1 is developmentally regulated during flower opening and fruit maturation, both processes may be mediated by ethylene in Citrus. Exogenous ethylene application also induced the expression of Fd1 both in flavedo and leaves. The induction of non-photosynthetic ferredoxins could be related with the demand for reducing power in non-green, but biosynthetically active, tissues. 相似文献
12.
Background
Photosynthetic organisms convert atmospheric carbon dioxide into numerous metabolites along the pathways to make new biomass. Aquatic photosynthetic organisms, which fix almost half of global inorganic carbon, have great potential: as a carbon dioxide fixation method, for the economical production of chemicals, or as a source for lipids and starch which can then be converted to biofuels. To harness this potential through metabolic engineering and to maximize production, a more thorough understanding of photosynthetic metabolism must first be achieved. A model algal species, C. reinhardtii, was chosen and the metabolic network reconstructed. Intracellular fluxes were then calculated using flux balance analysis (FBA). 相似文献13.
Background
Genome sequencing and bioinformatics are producing detailed lists of the molecular components contained in many prokaryotic organisms. From this 'parts catalogue' of a microbial cell, in silicorepresentations of integrated metabolic functions can be constructed and analyzed using flux balance analysis (FBA). FBA is particularly well-suited to study metabolic networks based on genomic, biochemical, and strain specific information.Results
Herein, we have utilized FBA to interpret and analyze the metabolic capabilities of Escherichia coli. We have computationally mapped the metabolic capabilities of E. coliusing FBA and examined the optimal utilization of the E. colimetabolic pathways as a function of environmental variables. We have used an in silicoanalysis to identify seven gene products of central metabolism (glycolysis, pentose phosphate pathway, TCA cycle, electron transport system) essential for aerobic growth of E. colion glucose minimal media, and 15 gene products essential for anaerobic growth on glucose minimal media. The in silico tpi -, zwf, and pta -mutant strains were examined in more detail by mapping the capabilities of these in silicoisogenic strains.Conclusions
We found that computational models of E. colimetabolism based on physicochemical constraints can be used to interpret mutant behavior. These in silicaresults lead to a further understanding of the complex genotype-phenotype relation. Supplementary information: 10.1186/1471-2105-1-1 相似文献14.
Kelly Gibson Jong-Sug Park Yasuko Nagai Seon-Kap HwangYoung-Chan Cho Kyung-Hee RohSi-Myung Lee Dong-Hern KimSang-Bong Choi Hiroyuki Ito Thomas W. Okita 《Plant science》2011,181(3):275-281
Improvements in plant productivity (biomass) and yield have centered on increasing the efficiency of leaf CO2 fixation and utilization of products by non-photosynthetic sink organs. We had previously demonstrated a correlation between photosynthetic capacity, plant growth, and the extent of leaf starch synthesis utilizing starch-deficient mutants. This finding suggested that leaf starch is used as a transient photosynthetic sink to recycle inorganic phosphate and, in turn, maximize photosynthesis. To test this hypothesis, Arabidopsis thaliana and rice (Oryza sativa L.) lines were generated with enhanced capacity to make leaf starch with minimal impact on carbon partitioning to sucrose. The Arabidopsis engineered plants exhibited enhanced photosynthetic capacity; this translated into increased growth and biomass. These enhanced phenotypes were displayed by similarly engineered rice lines. Manipulation of leaf starch is a viable alternative strategy to increase photosynthesis and, in turn, the growth and yields of crop and bioenergy plants. 相似文献
15.
Plastids (photosynthetic organelles of plants and algae) are known to have spread between eukaryotic lineages by secondary endosymbiosis, that is, by the uptake of a eukaryotic alga by another eukaryote. But the number of times this has taken place is controversial. This is particularly so in the case of eukaryotes with plastids derived from red algae, which are numerous and diverse. Despite their diversity, it has been suggested that all these eukaryotes share a recent common ancestor and that their plastids originated in a single endosymbiosis, the so-called "chromalveolate hypothesis." Here we describe a novel molecular character that supports the chromalveolate hypothesis. Fructose-1,6-bisphosphate aldolase (FBA) is a glycolytic and Calvin cycle enzyme that exists as two nonhomologous types, class I and class II. Red algal plastid-targeted FBA is a class I enzyme related to homologues from plants and green algae, and it would be predicted that the plastid-targeted FBA from algae with red algal secondary endosymbionts should be related to this class I enzyme. However, we show that plastid-targeted FBA of heterokonts, cryptomonads, haptophytes, and dinoflagellates (all photosynthetic chromalveolates) are class II plastid-targeted enzymes, completely unlike those of red algal plastids. The chromalveolate enzymes form a strongly supported group in FBA phylogeny, and their common possession of this unexpected plastid characteristic provides new evidence for their close relationship and a common origin for their plastids. 相似文献
16.
Cyanobacteria require large quantities of iron to maintain their photosynthetic machinery; however, in most environments iron is present in the form of insoluble iron oxides. Whether cyanobacteria can utilize these sources of iron, and the potential molecular mechanisms involved remains to be defined. There is increasing evidence that pili can facilitate electron donation to extracellular electron acceptors, like iron oxides in non-photosynthetic bacteria. In these organisms, the donation of electrons to iron oxides is thought to be crucial for maintaining respiration in the absence of oxygen. Our study investigates if PilA1 (major pilin protein) may also provide a mechanism to convert insoluble ferric iron into soluble ferrous iron. Growth experiments supported by spectroscopic data of a strain deficient in pilA1 indicate that the presence of the pilA1 gene enhances the ability to grow on iron oxides. These observations suggest a novel function of PilA1 in cyanobacterial iron acquisition. 相似文献
17.
Ulrich W. Hallier Jürgen M. Schmitt Ulrich Heber Svetlana S. Chaianova Alexander D. Volodarsky 《BBA》1978,504(1):67-83
In spite of only slightly subnormal pigment contents, two plastome mutants of Oenothera (Vα, Iσ) were practically incapable of photosynthetic CO2 fixation and another one exhibited considerably reduced photosynthesis (IVβ). While other photosynthetic enzymes were present as far as investigated, ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) activity was very low or missing altogether. As shown by gel electrophoresis, mutant IVβ contained some, though little, fraction I protein. In the other two mutants fraction I protein could not be detected. Also, neither the small nor the large subunit of ribulose-1,5-bisphosphate carboxylase could be found in these mutants. In immunodiffusion experiments with a monospecific antiserum against rye ribulose-1,5-bisphosphate carboxylase, only extracts from wild-type Oenothera produced visible precipitation lines. Still, the presence of very low levels of immunochemically reactive antigen was indicated for all three mutants. The highest level was observed in mutant IVβ. The behaviour of the mutant extracts suggested that the antigens of mutant and wild type leaves reacting with the antiserum were not identical. All mutants appeared to have a coupled electron transport system as shown by ATP measurements, light scattering and 515 nm absorption changes. Linear electron transport was possible in the mutants. Still, the photoresponse of cytochrome f and fluorescence measurements suggested altered electron transport properties in the mutants. These are interpreted to be secondary lesions of the photosynthetic apparatus caused by primary deficiency in ribulose-1,5-bisphosphate carboxylase activity. From the absence in two mutants (Vα, Iσ) of the small subunit of ribulose-1,5-bisphosphate carboxylase, which is known to be coded for by nuclear DNA and to be synthesized on cytoplasmic ribosomes, it appears that the genetic system of the plastids is capable of interfering with the genome-controlled synthesis of plastid components. 相似文献
18.
Pramod Kumar Yadav Gurmit Singh Budhayash Gautam Satendra Singh Madhu Yadav Upasana Srivastav Brijendra Singh 《Bioinformation》2013,9(3):158-164
Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged as a nosocomial pathogen to the
community which commonly causes skin and soft-tissue infections (SSTIs). This strain (MW2) has now become resistant to the
most of the beta-lactam antibiotics; therefore it is the urgent need to identify the novel drug targets. Recently fructose 1,6
biphosphate aldolase-II (FBA) has been identified as potential drug target in CA-MRSA. The FBA catalyses the retro-ketolic
cleavage of fructose-1,6-bisphosphate (FBP) to yield dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P)
in glycolytic pathway. In the present research work the 3D structure of FBA was predicted using the homology modeling method
followed by validation. The molecular dynamics simulation (MDS) of the predicted model was carried out using the 2000 ps time
scale and 1000000 steps. The MDS results suggest that the modeled structure is stable. The predicted model of FBA was used for
virtual screening against the NCI diversity subset-II ligand databases which contain 1364 compounds. Based on the docking energy
scores, it was found that top four ligands i.e. ZINC01690699, ZINC13154304, ZINC29590257 and ZINC29590259 were having lower
energy scores which reveal higher binding affinity towards the active site of FBA. These ligands might act as potent inhibitors for
the FBA so that the menace of antimicrobial resistance in CA-MRSA can be conquered. However, pharmacological studies are
required to confirm the inhibitory activity of these ligands against the FBA in CA-MRSA. 相似文献
19.
Sven Ihnken Jacco C. Kromkamp John Beardall Greg M. Silsbe 《Photosynthesis research》2014,119(3):257-272
Photosynthetic energy consumption and non-photosynthetic energy quenching processes are inherently linked. Both processes must be controlled by the cell to allow cell maintenance and growth, but also to avoid photodamage. We used the chlorophyte algae Dunaliella tertiolecta to investigate how the interactive regulation of photosynthetic and non-photosynthetic pathways varies along dissolved inorganic carbon (DIC) and photon flux gradients. Specifically, cells were transferred to DIC-deplete media to reach a CO2 compensation before being re-supplied with DIC at various concentrations and different photon flux levels. Throughout these experiments we monitored and characterized the photophysiological responses using pulse amplitude modulated fluorescence, oxygen evolution, 77 K fluorescence emission spectra, and fast-repetition rate fluorometry. O2 uptake was not significantly stimulated at DIC depletion, which suggests that O2 production rates correspond to assimilatory photosynthesis. Fluorescence-based measures of relative electron transport rates (rETRs) over-estimated oxygen-based photosynthetic measures due to a strong state-transitional response that facilitated high effective quantum yields. Adoption of an alternative fluorescence-based rETR calculation that accounts for state-transitions resulted in improved linear oxygen versus rETR correlation. This study shows the extraordinary capacity of D. tertiolecta to maintain stable effective quantum yields by flexible regulation of state-transitions. Uncertainties about the control mechanisms of state-transitions are presented. 相似文献