scholarly journals Physiological Biochemistry-Combined Transcriptomic Analysis Reveals Mechanism of Bacillus cereus G2 Improved Salt-Stress Tolerance of Glycyrrhiza uralensis Fisch. Seedlings by Balancing Carbohydrate Metabolism

2022 ◽  
Vol 12 ◽  
Author(s):  
Xiang Xiao ◽  
Qiuli Wang ◽  
Xin Ma ◽  
Duoyong Lang ◽  
Zhenggang Guo ◽  
...  
Keyword(s):  
Salt Stress ◽  
Bacillus Cereus ◽  
Starch Content ◽  
Tca Cycle ◽  
Soluble Starch ◽  
Glycyrrhiza Uralensis ◽  
Salt Stress Tolerance ◽  
Gene Encoding ◽  
The Tca Cycle ◽  
Carbohydrate Contents

Salt stress severely threatens the growth and productivity of Glycyrrhiza uralensis. Previous results found that Bacillus cereus G2 enhanced several carbohydrate contents in G. uralensis under salt stress. Here, we analyzed the changes in parameters related to growth, photosynthesis, carbohydrate transformation, and the glycolysis Embden-Meyerhof-Parnas (EMP) pathway-tricarboxylic acid (TCA) cycle by G2 in G. uralensis under salt stress. Results showed that G2 helped G. uralensis-accumulating photosynthetic pigments during photosynthesis, which could further increase starch, sucrose, and fructose contents during carbohydrate transformation. Specifically, increased soluble starch synthase (SSS) activity caused to higher starch content, which could induce α-amylase (AM) and β-amylase (BM) activities; increased sucrose content due to the increase of sucrose synthase (SS) activity through upregulating the gene-encoding SS, which decreased cell osmotic potential, and consequently, induced invertase and gene-encoding α-glucosidase that decomposed sucrose to fructose, ultimately avoided further water loss; increased fructose content-required highly hexokinase (HK) activity to phosphorylate in G. uralensis, thereby providing sufficient substrate for EMP. However, G2 decreased phosphofructokinase (PFK) and pyruvate kinase (PK) activities during EMP. For inducing the TCA cycle to produce more energy, G2 increased PDH activity that enhanced CA content, which further increased isocitrate dehydrogenase (ICDH) activity and provided intermediate products for the G. uralensis TCA cycle under salt stress. In sum, G2 could improve photosynthetic efficiency and carbohydrate transformation to enhance carbohydrate products, thereby releasing more chemical energy stored in carbohydrates through the EMP pathway-TCA cycle, finally maintain normal life activities, and promote the growth of G. uralensis under salt stress.

scholarly journals Regulation of the acuF Gene, Encoding Phosphoenolpyruvate Carboxykinase in the Filamentous Fungus Aspergillus nidulans

2002 ◽  
Vol 184 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Michael J. Hynes ◽  
Oliver W. Draht ◽  
Meryl A. Davis
Keyword(s):  
Carbon Source ◽  
Aspergillus Nidulans ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Carbon Sources ◽  
Tca Cycle ◽  
Northern Blotting ◽  
Gene Encoding ◽  
The Tca Cycle ◽  
Key Enzyme ◽  
Acetate Utilization

ABSTRACT Phosphoenolpyruvate carboxykinase (PEPCK) is a key enzyme required for gluconeogenesis when microorganisms grow on carbon sources metabolized via the tricarboxylic acid (TCA) cycle. Aspergillus nidulans acuF mutants isolated by their inability to use acetate as a carbon source specifically lack PEPCK. The acuF gene has been cloned and shown to encode a protein with high similarity to PEPCK from bacteria, plants, and fungi. The regulation of acuF expression has been studied by Northern blotting and by the construction of lacZ fusion reporters. Induction by acetate is abolished in mutants unable to metabolize acetate via the TCA cycle, and induction by amino acids metabolized via 2-oxoglutarate is lost in mutants unable to form 2-oxoglutarate. Induction by acetate and proline is not additive, consistent with a single mechanism of induction. Malate and succinate result in induction, and it is proposed that PEPCK is controlled by a novel mechanism of induction by a TCA cycle intermediate or derivative, thereby allowing gluconeogenesis to occur during growth on any carbon source metabolized via the TCA cycle. It has been shown that the facB gene, which mediates acetate induction of enzymes specifically required for acetate utilization, is not directly involved in PEPCK induction. This is in contrast to Saccharomyces cerevisiae, where Cat8p and Sip4p, homologs of FacB, regulate PEPCK as well as the expression of other genes necessary for growth on nonfermentable carbon sources in response to the carbon source present. This difference in the control of gluconeogenesis reflects the ability of A. nidulans and other filamentous fungi to use a wide variety of carbon sources in comparison with S. cerevisiae. The acuF gene was also found to be subject to activation by the CCAAT binding protein AnCF, a protein homologous to the S. cerevisiae Hap complex and the mammalian NFY complex.

α-Aminoadipate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2327-2334 ◽  
Author(s):  
Takashi Miyazaki ◽  
Junichi Miyazaki ◽  
Hisakazu Yamane ◽  
Makoto Nishiyama
Keyword(s):  
Thermus Thermophilus ◽  
Tca Cycle ◽  
Thermophilic Bacterium ◽  
Multiple Roles ◽  
Lysine Biosynthesis ◽  
Lag Phase ◽  
Gene Encoding ◽  
Branched Chain Amino Acid ◽  
The Tca Cycle ◽  
Branched Chain

The extremely thermophilic bacterium Thermus thermophilus HB27 synthesizes lysine through α-aminoadipate (AAA). In this study, a T. thermophilus gene encoding the enzyme that catalyses transamination of AAA was cloned as a mammalian kynurenine/AAA aminotransferase (Kat2) gene homologue. A T. thermophilus mutant with disruption of the Kat2 homologue required a longer lag phase for growth and showed slower growth in minimal medium. Furthermore, addition of AAA or lysine shortened the lag phase and improved the growth rate. The Kat2 homologue was therefore termed lysN. LysN recognizes not only 2-oxoadipate, an intermediate of lysine biosynthesis, but also 2-oxoisocaproate, 2-oxoisovalerate and 2-oxo-3-methylvalerate, intermediates of leucine, valine and isoleucine biosyntheses, respectively, along with oxaloacetate, a compound in the TCA cycle, as an amino acceptor. These results suggest multiple roles of LysN in several cellular metabolic pathways including lysine and branched-chain amino acid biosyntheses.

scholarly journals Toward an Understanding of the Structural and Mechanistic Aspects of Protein-Protein Interactions in 2-Oxoacid Dehydrogenase Complexes

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 407
Author(s):  
Natalia S. Nemeria ◽  
Xu Zhang ◽  
Joao Leandro ◽  
Jieyu Zhou ◽  
Luying Yang ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Tca Cycle ◽  
Degradation Pathway ◽  
Protein Protein Interactions ◽  
Gene Encoding ◽  
The Tca Cycle ◽  
Hybrid Complex ◽  
Key Enzyme ◽  
Lysine Degradation ◽  
Dehydrogenase Complex

The 2-oxoglutarate dehydrogenase complex (OGDHc) is a key enzyme in the tricarboxylic acid (TCA) cycle and represents one of the major regulators of mitochondrial metabolism through NADH and reactive oxygen species levels. The OGDHc impacts cell metabolic and cell signaling pathways through the coupling of 2-oxoglutarate metabolism to gene transcription related to tumor cell proliferation and aging. DHTKD1 is a gene encoding 2-oxoadipate dehydrogenase (E1a), which functions in the L-lysine degradation pathway. The potentially damaging variants in DHTKD1 have been associated to the (neuro) pathogenesis of several diseases. Evidence was obtained for the formation of a hybrid complex between the OGDHc and E1a, suggesting a potential cross talk between the two metabolic pathways and raising fundamental questions about their assembly. Here we reviewed the recent findings and advances in understanding of protein-protein interactions in OGDHc and 2-oxoadipate dehydrogenase complex (OADHc), an understanding that will create a scaffold to help design approaches to mitigate the effects of diseases associated with dysfunction of the TCA cycle or lysine degradation. A combination of biochemical, biophysical and structural approaches such as chemical cross-linking MS and cryo-EM appears particularly promising to provide vital information for the assembly of 2-oxoacid dehydrogenase complexes, their function and regulation.

scholarly journals Combined Proteomics and Metabolism Analysis Unravels Prominent Roles of Antioxidant System in the Prevention of Alfalfa (Medicago sativa L.) against Salt Stress

2020 ◽  
Vol 21 (3) ◽  
pp. 909 ◽  
Author(s):  
Jikai Li ◽  
Jemaa Essemine ◽  
Chen Shang ◽  
Hailing Zhang ◽  
Xiaocen Zhu ◽  
...  
Keyword(s):  
Salt Stress ◽  
Antioxidant System ◽  
Carbon Assimilation ◽  
Reducing Power ◽  
Net Photosynthesis ◽  
Tca Cycle ◽  
Glutathione Metabolism ◽  
Oxidation Reduction ◽  
The Tca Cycle ◽  
Metabolism Analysis

Alfalfa is the most extensively cultivated forage legume worldwide, and salinity constitutes the main environmental scourge limiting its growth and productivity. To unravel the potential molecular mechanism involved in salt tolerance in alfalfa, we accomplished a combined analysis of parallel reaction monitoring-based proteomic technique and targeted metabolism. Based on proteomic analysis, salt stress induced 226 differentially abundant proteins (DAPs). Among them, 118 DAPs related to the antioxidant system, including glutathione metabolism and oxidation-reduction pathways, were significantly up-regulated. Data are available via ProteomeXchange with identifier PXD017166. Overall, 107 determined metabolites revealed that the tricarboxylic acid (TCA) cycle, especially the malate to oxaloacetate conversion step, was strongly stimulated by salt stress. This leads to an up-regulation by about 5 times the ratio of NADPH/NADP+, as well as about 3 to 5 times in the antioxidant enzymes activities, including those of catalase and peroxidase and proline contents. However, the expression levels of DAPs related to the Calvin–Benson–Bassham (CBB) cycle and photorespiration pathway were dramatically inhibited following salt treatment. Consistently, metabolic analysis showed that the metabolite amounts related to carbon assimilation and photorespiration decreased by about 40% after exposure to 200 mM NaCl for 14 d, leading ultimately to a reduction in net photosynthesis by around 30%. Our findings highlighted also the importance of the supplied extra reducing power, thanks to the TCA cycle, in the well-functioning of glutathione to remove and scavenge the reactive oxygen species (ROS) and mitigate subsequently the oxidative deleterious effect of salt on carbon metabolism including the CBB cycle.

scholarly journals Genetic and Biochemical Interactions Involving Tricarboxylic Acid Cycle (TCA) Function Using a Collection of Mutants Defective in All TCA Cycle Genes

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 153-166 ◽  
Author(s):  
Beata Przybyla-Zawislak ◽  
Devi M Gadde ◽  
Kurt Ducharme ◽  
Mark T McCammon
Keyword(s):  
Citrate Synthase ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Sources ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Gene Encoding ◽  
Unique Role ◽  
Yeast Strains ◽  
The Tca Cycle ◽  
Mutant Collection

Abstract The eight enzymes of the tricarboxylic acid (TCA) cycle are encoded by at least 15 different nuclear genes in Saccharomyces cerevisiae. We have constructed a set of yeast strains defective in these genes as part of a comprehensive analysis of the interactions among the TCA cycle proteins. The 15 major TCA cycle genes can be sorted into five phenotypic categories on the basis of their growth on nonfermentable carbon sources. We have previously reported a novel phenotype associated with mutants defective in the IDH2 gene encoding the Idh2p subunit of the NAD+-dependent isocitrate dehydrogenase (NAD-IDH). Null and nonsense idh2 mutants grow poorly on glycerol, but growth can be enhanced by extragenic mutations, termed glycerol suppressors, in the CIT1 gene encoding the TCA cycle citrate synthase and in other genes of oxidative metabolism. The TCA cycle mutant collection was utilized to search for other genes that can suppress idh2 mutants and to identify TCA cycle genes that display a similar suppressible growth phenotype on glycerol. Mutations in 7 TCA cycle genes were capable of functioning as suppressors for growth of idh2 mutants on glycerol. The only other TCA cycle gene to display the glycerol-suppressor-accumulation phenotype was IDH1, which encodes the companion Idh1p subunit of NAD-IDH. These results provide genetic evidence that NAD-IDH plays a unique role in TCA cycle function.

scholarly journals Teleological role of L-2-hydroxyglutarate dehydrogenase in the kidney

2020 ◽  
Vol 13 (11) ◽  
pp. dmm045898 ◽  
Author(s):  
Garrett Brinkley ◽  
Hyeyoung Nam ◽  
Eunhee Shim ◽  
Richard Kirkman ◽  
Anirban Kundu ◽  
...  
Keyword(s):  
Isotope Labeling ◽  
Physiological Role ◽  
Tca Cycle ◽  
Bioinformatic Analysis ◽  
Renal Tumors ◽  
Gene Encoding ◽  
Renal Metabolism ◽  
Cycle Enzyme ◽  
The Tca Cycle

ABSTRACTL-2-hydroxyglutarate (L-2HG) is an oncometabolite found elevated in renal tumors. However, this molecule might have physiological roles that extend beyond its association with cancer, as L-2HG levels are elevated in response to hypoxia and during Drosophila larval development. L-2HG is known to be metabolized by L-2HG dehydrogenase (L2HGDH), and loss of L2HGDH leads to elevated L-2HG levels. Despite L2HGDH being highly expressed in the kidney, its role in renal metabolism has not been explored. Here, we report our findings utilizing a novel CRISPR/Cas9 murine knockout model, with a specific focus on the role of L2HGDH in the kidney. Histologically, L2hgdh knockout kidneys have no demonstrable histologic abnormalities. However, GC-MS metabolomics demonstrates significantly reduced levels of the TCA cycle intermediate succinate in multiple tissues. Isotope labeling studies with [U-13C] glucose demonstrate that restoration of L2HGDH in renal cancer cells (which lowers L-2HG) leads to enhanced incorporation of label into TCA cycle intermediates. Subsequent biochemical studies demonstrate that L-2HG can inhibit the TCA cycle enzyme α-ketoglutarate dehydrogenase. Bioinformatic analysis of mRNA expression data from renal tumors demonstrates that L2HGDH is co-expressed with genes encoding TCA cycle enzymes as well as the gene encoding the transcription factor PGC-1α, which is known to regulate mitochondrial metabolism. Restoration of PGC-1α in renal tumor cells results in increased L2HGDH expression with a concomitant reduction in L-2HG levels. Collectively, our analyses provide new insight into the physiological role of L2HGDH as well as mechanisms that promote L-2HG accumulation in disease states.

scholarly journals Salt Stress Tolerance of Dark Septate Endophytes Is Independent of Melanin Accumulation

2020 ◽  
Vol 11 ◽  
Author(s):  
Dalia A. Gaber ◽  
Charlotte Berthelot ◽  
Iris Camehl ◽  
Gábor M. Kovács ◽  
Damien Blaudez ◽  
...  
Keyword(s):  
Salt Stress ◽  
Stress Tolerance ◽  
High Salt ◽  
Dark Septate Endophytes ◽  
Growth Responses ◽  
Salt Stress Tolerance ◽  
Gene Encoding ◽  
Melanin Biosynthesis ◽  
Rna Accumulation ◽  
Eukaryotic Organisms

Dark septate endophytes (DSEs) represent a diverse group of root-endophytic fungi that have been isolated from plant roots in many different natural and anthropogenic ecosystems. Melanin is widespread in eukaryotic organisms and possesses various functions such as protecting human skin from UV radiation, affecting the virulence of pathogens, and playing a role in development and physiology of insects. Melanin is a distinctive feature of the cell walls of DSEs and has been thought to protect these fungi from abiotic stress. Melanin in DSEs is assumed to be synthesized via the 1,8-dihydroxynaphthalene (DHN) pathway. Its function in alleviation of salt stress is not yet known. The aims of this study were: (i) investigating the growth responses of three DSEs (Periconia macrospinosa, Cadophora sp., and Leptodontidium sp.) to salt stress, (ii) analyzing melanin production under salt stress and, (iii) testing the role of melanin in salt stress tolerance of DSEs. The study shows that the three DSE species can tolerate high salt concentrations. Melanin content increased in the hyphae of all DSEs at 100 mM salt, but decreased at 500 mM. This was not reflected in the RNA accumulation of the gene encoding scytalone dehydratase which is involved in melanin biosynthesis. The application of tricyclazole, a DHN-melanin biosynthesis inhibitor, did not affect either salt stress tolerance or the accumulation of sodium in the hyphae. In addition, melanin biosynthesis mutants of Leptodontidium sp. did not show decreased growth performance compared to the wild-type, especially not at high salt concentrations. This indicates that DSEs can live under salt stress and withstand these conditions regardless of melanin accumulation.

scholarly journals RNA-seq reveals that multiple plant hormones are regulated by Bacillus cereus G2 in Glycyrrhiza uralensis subjected to salt stress

2021 ◽  
Vol 16 (1) ◽  
pp. 591-603
Author(s):  
Xiang Xiao ◽  
Qiuli Wang ◽  
Duoyong Lang ◽  
Yuankui Chu ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Salt Stress ◽  
Bacillus Cereus ◽  
Plant Hormones ◽  
Glycyrrhiza Uralensis ◽  
Rna Seq

Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

Sign in / Sign up

Export Citation Format

Share Document