Aim Oxaloacetate （OA） is one of the intermediates in the Krebs cycle. In addition to its role in the metabolism of energy production, OA may have other effects on the cell. We report in the present study that OA cou...Aim Oxaloacetate （OA） is one of the intermediates in the Krebs cycle. In addition to its role in the metabolism of energy production, OA may have other effects on the cell. We report in the present study that OA could have a cell type dependent cytoto^ic effect on the human hepatic carcinoma cell line HepG2 through induction of apoptosis and ROS accumulation. In our study, OA decreased the viability and colony formation of HepG2 cell and induced cell death. Caspase-3 activity was increased, pro-apoptotic protein Bax was up-regulated, and anti-ap- optotic protein Bcl-2 was clown-regulated in OA-treated HepG2 cells indicating that apoptosis through the intrinsic pathway was involved in the death of the cell. The level of reactive oxygen species （ROS） in OA-treated HepG2 cells was increased. Anti-oxidant N-acetylcysteine （NAC） and glutathione （GSH） prevented the viability of the cell induced by OA from decrease but could not alleviate the enhanced level of apoptotic Bax/Bcl-2 mRNA expres- sion ratio, which suggests that the OA-induced apoptosis of HepG2 cell is not driven by oxidative damage and at least two distinct mechanisms, one mediated by ROS and one involving apoptosis, lead to the cytotoxic effect of OA on HepG2 cells. These studies expand the biological functional repertoire of OA and provide a mechanism by which hepatocellular carcinoma may be targeted by OA to kill the cancer cells.展开更多
The line of T240-6 was selected from 32 SC 2 lines of immature embryo culture of T240 (common wheat (Triticum aestivum L.)× Wheat-Haynaldia villosa (L.) Schur. 6D/6V substitution line) through powdery mildew ch...The line of T240-6 was selected from 32 SC 2 lines of immature embryo culture of T240 (common wheat (Triticum aestivum L.)× Wheat-Haynaldia villosa (L.) Schur. 6D/6V substitution line) through powdery mildew characterization, glutamate oxaloacetate transaminase (GOT) enzyme and gliadin (Gli) analyses and in situ hybridization. All of the individual plants resistant to powdery mildew lacked the locus of GOT at 6VL arm (GOT-V 2) and had gliadin locus at 6VS arm (Gli-V 2) of Haynaldia villosa. All the plants resistant to powdery mildew had one or two telocentric chromosomes that did not pair with wheat chromosomes but paired between themselves. T240-6 was identified as a telocentric line through in situ hybridization.展开更多
This study aimed to rationally identify new targets for improving isoleucine production.The transcription levelsof the key genes and intermediate metabolite levels involved in the isoleucine synthesis pathway of Coryn...This study aimed to rationally identify new targets for improving isoleucine production.The transcription levelsof the key genes and intermediate metabolite levels involved in the isoleucine synthesis pathway of Corynebacteriumglutamicum ATCC13032and C.glutamicum YILW,a isoleucine-producing strain derived from the parental strain ATCC13032,were compared.The gene pyc was down-regulated,which might consequently lead to reduced supply of oxaloacetate.Then pyc was overexpressed in C.glutamicum YILW(denoted as YILW-1),resulting in increased oxaloacetate concentrationand isoleucine production(from1.32to3.32μmol/g(md)and from5.18to5.81g/L)but higher accumulation of lysine andintracellular2-ketobutyrate as byproduct.The ilvBNC operon was further overexpressed in YILW-1(denoted as YILW-2),resulting in production of up to6.63g/L isoleucine.To enhance exportation and consequently further increase the productionof isoleucine,the isoleucine exporter genes brnE and brnF was overexpressed in YILW-2(denoted as YILW-3),leadingto increased production of isoleucine(7.31g/L)by10.3%as compared to that of YILW-2.The strategy resulted in41.1%higher isoleucine production(from5.18to7.31g/L)and40.0%higher yield(from0.10to0.14g/g glucose)together withlower by-product lelvels by YILW-3as compared to C.glutamicum YILW.It could be concluded that overexpression of thepyc,ilvBNC operon as well as brnE and brnF based on transcription and metabolite pool analysis could significantly elevateisoleucine production and decrease by-product concentration levels.展开更多
In the present, investigation effects of sub-lethal dose of purified paper wasp Ropalidia marginata venom toxins were evaluated on important metabolic enzymes i.e. ALP ACP, GPT, GOT, LDH, and AchE enzyme activity in s...In the present, investigation effects of sub-lethal dose of purified paper wasp Ropalidia marginata venom toxins were evaluated on important metabolic enzymes i.e. ALP ACP, GPT, GOT, LDH, and AchE enzyme activity in serum, liver, and gastrocnemius muscles of albino mice. Alkaline phosphatase was found to be increased up to 119.9% at the 6<sup>th</sup> hr of the toxin injection in comparison to control. This elevation may be due to cytolysis. Maximum increase i.e., 153.33% level of glutamate pyruvate transaminase (GPT) was found at 6 hrs of 40% of 24-h LD<sub>50</sub> treatment while it was found to be 151.1% at 6 hrs of 24 hr 80% of LD<sub>50</sub>, venom injection. A significant elevation was observed in LDH activity in serum, liver, and muscles, while the activity of AchE was decreased in serum, liver, and gastrocnemius muscles of albino mice after injecting the sub-lethal dose of Ropalidia marginata venom. This increase in the activity of LDH produces liver damage, massive disintegration and necrosis of hepatic cells. This elevation in LDH level led to a significant increase in the glucose catabolism and elevated oxidative stress in muscle and liver cells. It also displays insufficient oxygen supply and consequently leads to cell death. In experimental animals, venom toxin treatment decreased AchE level, and animals showed muscular paralysis. When mice were treated with 40% and 80% of 24-h LD<sub>50</sub> of purified venom caused a significant (p < 0.05) elevation in the level of ACP, GOT, GPT, and LDH while the reduction in ALP and AChE level. Present study will be useful in the development of prototypes for study of pharmacological and therapeutic effects of various venom toxins. For this purpose structure activity relationship of enzyme and venom toxin, its due interaction to various metabolic enzymes and receptors must be explored.展开更多
Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, ...Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, a oat-deleted mutant was derived from wild-type A. niger ATCC1015 using the double-crossover chromosome replacement technique. Then batch fermentation was performed to evaluate the mutant. Compared with the wild type, the mutant showed lower organic acids production, with the experimental data that the production of pyruvate and 2-ketoglutarate decreased by 31.6% and 35.7%, respectively, and by contrast, the mutant showed higher glycerol formation. The results suggest that OAT gene plays significant roles on metabolism in A. niger.展开更多
In the present investigation, in vivo effects of purified ticks’ saliva toxin were evaluated on the level of certain important cellular metabolic enzymes i.e. acid phosphatase (ACP), alkaline phosphatase (ALP), gluta...In the present investigation, in vivo effects of purified ticks’ saliva toxin were evaluated on the level of certain important cellular metabolic enzymes i.e. acid phosphatase (ACP), alkaline phosphatase (ALP), glutamate pyruvate transaminase, glutamate oxaloacetate transaminase and lactic dehydrogenase. For this purpose, sub-lethal doses, 40% and 80% of 24 h LD50 purified saliva toxins of Rhipicephalus microplus (Canestrini, 1888) were injected subcutaneously in the albino mice. In treated mice saliva toxins targeted membrane-bound enzymes i.e. serum acid phosphatase and alkaline phosphatase, its level was increased from 118.30% to 163.63% at the 6th hr in comparison to the control. Besides this, the levels of serum glutamate pyruvate transaminase (GPT) and glutamate oxaloacetate transaminase (GOT) and lactic dehydrogenase (LDH) also increased up to 161.11% (at 6th hr), 148.27 (at 8th hr) and 125.45% (at 6th hr) respectively in comparison to control. An increase in the level of LDH showed insufficient oxygen supply, massive disintegration of cells and leakage of the enzyme into the circulation. It clearly indicated the toxic effects of saliva toxins on the membrane of blood cells, hepatocytes and myocardial muscle cell functions in albino mice. On the other hand activity of acetyl cholinesterase was reduced by 65.51% at the 6th hr of the saliva toxin injection in comparison to the control. This inhibition of acetyl cholinesterase activity caused the accumulation of acetylcholine molecules at the synaptic junctions and led to prolonged activation of acetylcholine receptors. It caused permanent stimulation of nerves and muscle cells that may result in muscular paralysis and finally death of the animal.展开更多
文摘Aim Oxaloacetate （OA） is one of the intermediates in the Krebs cycle. In addition to its role in the metabolism of energy production, OA may have other effects on the cell. We report in the present study that OA could have a cell type dependent cytoto^ic effect on the human hepatic carcinoma cell line HepG2 through induction of apoptosis and ROS accumulation. In our study, OA decreased the viability and colony formation of HepG2 cell and induced cell death. Caspase-3 activity was increased, pro-apoptotic protein Bax was up-regulated, and anti-ap- optotic protein Bcl-2 was clown-regulated in OA-treated HepG2 cells indicating that apoptosis through the intrinsic pathway was involved in the death of the cell. The level of reactive oxygen species （ROS） in OA-treated HepG2 cells was increased. Anti-oxidant N-acetylcysteine （NAC） and glutathione （GSH） prevented the viability of the cell induced by OA from decrease but could not alleviate the enhanced level of apoptotic Bax/Bcl-2 mRNA expres- sion ratio, which suggests that the OA-induced apoptosis of HepG2 cell is not driven by oxidative damage and at least two distinct mechanisms, one mediated by ROS and one involving apoptosis, lead to the cytotoxic effect of OA on HepG2 cells. These studies expand the biological functional repertoire of OA and provide a mechanism by which hepatocellular carcinoma may be targeted by OA to kill the cancer cells.
文摘The line of T240-6 was selected from 32 SC 2 lines of immature embryo culture of T240 (common wheat (Triticum aestivum L.)× Wheat-Haynaldia villosa (L.) Schur. 6D/6V substitution line) through powdery mildew characterization, glutamate oxaloacetate transaminase (GOT) enzyme and gliadin (Gli) analyses and in situ hybridization. All of the individual plants resistant to powdery mildew lacked the locus of GOT at 6VL arm (GOT-V 2) and had gliadin locus at 6VS arm (Gli-V 2) of Haynaldia villosa. All the plants resistant to powdery mildew had one or two telocentric chromosomes that did not pair with wheat chromosomes but paired between themselves. T240-6 was identified as a telocentric line through in situ hybridization.
文摘This study aimed to rationally identify new targets for improving isoleucine production.The transcription levelsof the key genes and intermediate metabolite levels involved in the isoleucine synthesis pathway of Corynebacteriumglutamicum ATCC13032and C.glutamicum YILW,a isoleucine-producing strain derived from the parental strain ATCC13032,were compared.The gene pyc was down-regulated,which might consequently lead to reduced supply of oxaloacetate.Then pyc was overexpressed in C.glutamicum YILW(denoted as YILW-1),resulting in increased oxaloacetate concentrationand isoleucine production(from1.32to3.32μmol/g(md)and from5.18to5.81g/L)but higher accumulation of lysine andintracellular2-ketobutyrate as byproduct.The ilvBNC operon was further overexpressed in YILW-1(denoted as YILW-2),resulting in production of up to6.63g/L isoleucine.To enhance exportation and consequently further increase the productionof isoleucine,the isoleucine exporter genes brnE and brnF was overexpressed in YILW-2(denoted as YILW-3),leadingto increased production of isoleucine(7.31g/L)by10.3%as compared to that of YILW-2.The strategy resulted in41.1%higher isoleucine production(from5.18to7.31g/L)and40.0%higher yield(from0.10to0.14g/g glucose)together withlower by-product lelvels by YILW-3as compared to C.glutamicum YILW.It could be concluded that overexpression of thepyc,ilvBNC operon as well as brnE and brnF based on transcription and metabolite pool analysis could significantly elevateisoleucine production and decrease by-product concentration levels.
文摘In the present, investigation effects of sub-lethal dose of purified paper wasp Ropalidia marginata venom toxins were evaluated on important metabolic enzymes i.e. ALP ACP, GPT, GOT, LDH, and AchE enzyme activity in serum, liver, and gastrocnemius muscles of albino mice. Alkaline phosphatase was found to be increased up to 119.9% at the 6<sup>th</sup> hr of the toxin injection in comparison to control. This elevation may be due to cytolysis. Maximum increase i.e., 153.33% level of glutamate pyruvate transaminase (GPT) was found at 6 hrs of 40% of 24-h LD<sub>50</sub> treatment while it was found to be 151.1% at 6 hrs of 24 hr 80% of LD<sub>50</sub>, venom injection. A significant elevation was observed in LDH activity in serum, liver, and muscles, while the activity of AchE was decreased in serum, liver, and gastrocnemius muscles of albino mice after injecting the sub-lethal dose of Ropalidia marginata venom. This increase in the activity of LDH produces liver damage, massive disintegration and necrosis of hepatic cells. This elevation in LDH level led to a significant increase in the glucose catabolism and elevated oxidative stress in muscle and liver cells. It also displays insufficient oxygen supply and consequently leads to cell death. In experimental animals, venom toxin treatment decreased AchE level, and animals showed muscular paralysis. When mice were treated with 40% and 80% of 24-h LD<sub>50</sub> of purified venom caused a significant (p < 0.05) elevation in the level of ACP, GOT, GPT, and LDH while the reduction in ALP and AChE level. Present study will be useful in the development of prototypes for study of pharmacological and therapeutic effects of various venom toxins. For this purpose structure activity relationship of enzyme and venom toxin, its due interaction to various metabolic enzymes and receptors must be explored.
文摘Mitochondrial oxaloacetate transporter protein encoded by OAT gene transports oxaloacetate from cytoplasm into mitochondria. To investigate the primary effects of OAT gene on relative metabolism in Aspergillus niger, a oat-deleted mutant was derived from wild-type A. niger ATCC1015 using the double-crossover chromosome replacement technique. Then batch fermentation was performed to evaluate the mutant. Compared with the wild type, the mutant showed lower organic acids production, with the experimental data that the production of pyruvate and 2-ketoglutarate decreased by 31.6% and 35.7%, respectively, and by contrast, the mutant showed higher glycerol formation. The results suggest that OAT gene plays significant roles on metabolism in A. niger.
文摘In the present investigation, in vivo effects of purified ticks’ saliva toxin were evaluated on the level of certain important cellular metabolic enzymes i.e. acid phosphatase (ACP), alkaline phosphatase (ALP), glutamate pyruvate transaminase, glutamate oxaloacetate transaminase and lactic dehydrogenase. For this purpose, sub-lethal doses, 40% and 80% of 24 h LD50 purified saliva toxins of Rhipicephalus microplus (Canestrini, 1888) were injected subcutaneously in the albino mice. In treated mice saliva toxins targeted membrane-bound enzymes i.e. serum acid phosphatase and alkaline phosphatase, its level was increased from 118.30% to 163.63% at the 6th hr in comparison to the control. Besides this, the levels of serum glutamate pyruvate transaminase (GPT) and glutamate oxaloacetate transaminase (GOT) and lactic dehydrogenase (LDH) also increased up to 161.11% (at 6th hr), 148.27 (at 8th hr) and 125.45% (at 6th hr) respectively in comparison to control. An increase in the level of LDH showed insufficient oxygen supply, massive disintegration of cells and leakage of the enzyme into the circulation. It clearly indicated the toxic effects of saliva toxins on the membrane of blood cells, hepatocytes and myocardial muscle cell functions in albino mice. On the other hand activity of acetyl cholinesterase was reduced by 65.51% at the 6th hr of the saliva toxin injection in comparison to the control. This inhibition of acetyl cholinesterase activity caused the accumulation of acetylcholine molecules at the synaptic junctions and led to prolonged activation of acetylcholine receptors. It caused permanent stimulation of nerves and muscle cells that may result in muscular paralysis and finally death of the animal.
