L-valine is an important branched-chain amino acid widely used in the food, pharmaceutical, and feed industries. Microbial fermentation has become the primary production method for L-valine. However, current industrial production still faces issues such as inefficient carbon flux utilization, imbalance in cofactor supply and demand, and suboptimal fermentation processes, which limit the efficient synthesis of L-valine. To further enhance the production performance of L-valine, In this study, metabolic engineering was conducted for a previously constructed Escherichia coli strain with a high yield of L-valine to optimize carbon flux distribution and balance cofactor consumption. Dual-phase oxygen-controlled fermentation was carried out to enhance L-valine production. Firstly, to address the pyruvate loss, we knocked out multiple competing pathway genes (ldhA, poxB, pflB, frdA, and pta), which resulted in a 48% increase in flask yield of the constructed strain VL-04. Next, we optimized the cofactor supply and demand balance by replacing ilvE with bcd (NADH-preferential) from Bacillus subtilis to construct the strain VL-06, which achieved a flask yield of 22.80 g/L, a further improvement of 25.8%. Subsequently, the fermentation conditions of VL-06 were optimized in a 5 L bioreactor with dual-phase oxygen-controlled fermentation. After optimization, the L-valine production reached 86.44 g/L in 26 h, with a glucose-to-acid conversion rate of 44.08% and a production intensity of 3.32 g/(L·h). This study not only shortens the time for L-valine production but also improves the economic efficiency, providing insights for similar fermentation processes employing dual-phase oxygen control.
Metabolic Engineering/methods* ; Escherichia coli/genetics* ; Valine/biosynthesis* ; Fermentation ; Bacillus subtilis/genetics*

L-valine is an important essential branched-chain amino acid widely used in industries such as feed, pharmaceuticals, and food. In order to further enhance the production performance of L-valine, this study systematically engineered the metabolism of a Corynebacterium glutamicum strain, preserved in the laboratory, which is capable of producing L-valine. First, strain VH-9 was obtained by enhancing the precursor supply, synthesis pathway, and transport system of L-valine. In a 5 L fermenter, the titer, yield, and productivity of L-valine were 76.6 g/L, 0.45 g/g, and 2.39 g/(L·h), respectively. Furthermore, strain VH-18 was obtained by enhancing the uptake of substrate glucose and balancing energy supply to reduce succinate accumulation, with the titer, yield, and productivity of L-valine increased to 82.7 g/L, 0.52 g/g, and 2.58 g/(L·h), respectively. After optimization of fermentation conditions, the titer, yield, and productivity of L-valine in strain VH-18 were further improved to 88.7 g/L, 0.54 g/g, and 2.77 g/(L·h), respectively. This study has achieved the high-efficiency production of L-valine through a systems metabolic engineering strategy.
Corynebacterium glutamicum/genetics* ; Metabolic Engineering/methods* ; Valine/biosynthesis* ; Fermentation ; Glucose/metabolism*

In the current study, we synthesized a 16-residue-long peptide VR with the aim of inspecting the feasibility to design beta-hairpin-like antimicrobial peptide. The peptide was designed by alternating arrangement of arginine and valine and linking two stranded antiparallel beta-sheet with a short loop segment (DPG) and a disulfide bridge. Antimicrobial and hemolytic activities were investigated. Melittin was chosen as a control peptide. We also tested bactericidal kinetics and salt sensitivity. Results show that VR had similar antibacterial activity compared with melittin. However, VR displayed much less hemolytic activity than melittin. These results suggest that VR had higher cell selectivity than melittin. The antibacterial activity of VR was not inhibited in the presence of 25 and 50 mmol/L NaCl. VR still possessed antibacterial activity in the presence of 100 mmol/L NaCl. Collectively, the de novo peptide VR displayed high antimicrobial activity, low hemolytic activity, and salt resistant, indicating that VR was a promising candidate for novel antimicrobial applications.
Anti-Infective Agents ; chemistry ; pharmacology ; Antimicrobial Cationic Peptides ; biosynthesis ; chemistry ; pharmacology ; Arginine ; chemistry ; Bacteria ; drug effects ; Drug Design ; Escherichia coli ; drug effects ; Hemolysis ; drug effects ; Microbial Sensitivity Tests ; Staphylococcus aureus ; drug effects ; Valine ; chemistry

OBJECTIVETo investigate the changes of proto-oncogene c-fos, c-jun mRNA expression in angiotensin II (Ang II)-induced hypertrophy and effects of tanshinone II A (Tan) in the primary culture of neonatal rat cardiomyocytes.

METHODTwelve neonatal Wistar rats aged one day old of clean grade and both sexes were selected to isolate and culture cardiomyocytes. The cardiomyocytes were divided into: normal control group, Ang II (10(-6) mol x L(-1)) group, Ang II (10(-6) mol x L(-1)) +Tan (10(-8) g x L(-1)) group, Ang II (10(-6) mol x L(-1)) + valsartan (10(-6) mol x L(-1)) group, Tan (10(-8) g x L(-1)) group, valsartan (10(-6) mol x L(-1)) group. The cardiomyocyte size was determined by phase contrast microscope, the rate of protein synthesis in cardiomyocytes was measured by 3H-leucine incorporation. The c-fos, c-jun mRNA expression of cardiomyocytes were assessed using reverse transcription polymerase chain reaction (RT-PCR).

RESULTAng II was added to the culture medium and 30 min later, the c-fos, c-jun mRNA expression of cardiomyocytes increased significantly (P < 0. 01). After Ang II took effect for 24 h, the rate of protein synthesis in Ang II group increased more prominently than that in normal control group (P < 0.01). After Ang II took effect for 7 days, the size of cardiomyocyte in Ang II group increased obviously (P < 0. 05). If tanshinone II or valsartan was added to the culture medium before Ang II, both of them could inhibit the increase of c-fos, c-jun mRNA expression (P < 0.01), cardiomyocyte protein synthesis rate (P < 0.01), and cardiomyocyte size (P < 0.05) induced by Ang II.

CONCLUSIONTanshinone II could ameliorate Ang II-induced cardiomyocytes hypertrophy by inhabiting c-fos, c-jun mRNA expression.

Angiotensin II ; biosynthesis ; pharmacology ; Animals ; Cardiomegaly ; chemically induced ; metabolism ; pathology ; Diterpenes, Abietane ; Gene Expression Regulation ; drug effects ; Genes, fos ; genetics ; Genes, jun ; genetics ; Myocytes, Cardiac ; drug effects ; metabolism ; pathology ; Phenanthrenes ; pharmacology ; Proto-Oncogene Proteins c-fos ; genetics ; Proto-Oncogene Proteins c-jun ; genetics ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

OBJECTIVETo investigate the expression of Angiotensin II type 1 receptor (AT1R) in tissue and cell lines of squamous cervical carcinomas and its clinical significance, and to explore the molecular mechamisms of angiotensin II and AT1R activity in the process of cervical carcinogenesis.

METHODS(1) The levels of AT1R mRNA were examined by quantitative reverse transcriptase-polymerase chain reaction( RT-PCR) in paraffin-embedded tissues from 35 cases of cervical squamous cell carcinoma, 15 cases of cervical intraepithelial neoplasia (CIN), and 15 cases of normal cervix, and in Siha and C33a cells. The expression of AT1R protein in 65 specimens of cervix tissue sections was evaluated by immunohistochemistry. The corelation between the expressions of AT1R and its clinicopathologic features was analyzed accordingly. (2) After the Siha and C33a cells were treated at different concentrations of Angiotensin II (0, 10(-10) mol/L, 10(-9) mol/L, 10(-8) mol/L, 10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L) for different time in culture, the cell proliferation was determined by methylthiazolyl tetrazolium (MTT) assay. The vascular endothelial growth factor (VEGF) expression was examined by enzyme-linked immuno-absordent assay (ELISA).

RESULTS(1) AT1R mRNA expression was detected in the two cervix cancer cell lines. The positive rate of ATIR mRNA was 77.1%, 40.0% and 0, respectively, in squamous cell carcinomas, cervical intraepithelial neoplasia and normal cervical tissues, while their mRNA quantities were 0.3863 +/- 0.041, 0.0768 +/- 0.035 and 0, respectively. There was statistically a significant difference between them (P < 0.01). The average staining intensity of AT1R protein was stronger in invasive carcinoma cells than that in dysplasia tissues and normal ones (P < 0.01). Among 65 cases of squamous cell carcinomas, the expressions of AT1R mRNA and protein increased with pathological grading (P < 0.05), while it was neither correlated with clinical stage nor pelvic lymph node metastasis (P > 0.05). The level of AT1R protein expression corresponded to that of its mRNA. (2) Angiotensin II promoted the cell growth of cervical cancer cell lines Siha and C33a and induced secretion of VEGF from cells in a dose-dependent manner (P < 0.01), and the expression of VEGF was reversed by the addition of valsatan (an antagonist of angiotensin II type 1 receptor) (P < 0.01).

CONCLUSIONAngiotensin II is involved in the progression of cervical carcinoma, since it may increase the proliferation activity of cancer cells, induce secretion of VEGF through AT1R synchronously, and results in an increase of angiogenesis in tumors. It suggests that use of AT1R antagonists may be an useful therapeutic strategy for cervical carcinoma.

Angiotensin II ; pharmacology ; Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Carcinoma, Squamous Cell ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cervical Intraepithelial Neoplasia ; genetics ; metabolism ; pathology ; Cervix Uteri ; metabolism ; pathology ; Dose-Response Relationship, Drug ; Enzyme-Linked Immunosorbent Assay ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; Lymphatic Metastasis ; Neoplasm Staging ; RNA, Messenger ; biosynthesis ; genetics ; Receptor, Angiotensin, Type 1 ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Tetrazoles ; pharmacology ; Uterine Cervical Neoplasms ; genetics ; metabolism ; pathology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan ; Vascular Endothelial Growth Factor A ; secretion

OBJECTIVETo investigate the effects of ox-LDL, ACEI and ARB on expressions and activities of TF and TFPI in VSMC.

METHODS(1) Rabbit VSMC was cultured by explant-attached method in vitro. (2) The effects of ox-LDL and valsartan on TF and TFPI expressions were analyzed by immunohistochemistry and immunofluorescence. Laser scanning confocal microscopy were applied to analyze the effects of ox-LDL and valsartan on TF expression. The effects of ox-LDL, valsartan and captopril on TF and TFPI antigen expressions were analyzed by ELISA. Chromogenic substrate method was used to determine the effects of ox-LDL, valsartan and captopril on TF activity. The effects of ox-LDL and valsartan on TF mRNA expression were analyzed by RT-PCR.

RESULTS(1) ox-LDL could upregulate TF antigen, activity and TF expression at mRNA level and downregulate TFPI antigen. (2) Valsartan and captopril could reduce TF antigen and activity in VSMC treated by ox-LDL, and valsartan reduce it in a dose-dependent manner. Valsartan could also attenuate TF expression at mRNA level in VSMC treated by ox-LDL. (3) Using ELISA, valsartan and captopril could also enhance TFPI antigen in VSMC treated by ox-LDL.

CONCLUSIONOur study showed upregulated TF and downregulated TFPI expression and activity by ox-LDL and these effects could be reversed by ACEI and ARB indicating a new insight on the antiatherosclerotic effects of ACEI and ARB.

Animals ; Captopril ; pharmacology ; Cells, Cultured ; Endothelium, Vascular ; cytology ; metabolism ; Male ; Proton-Translocating ATPases ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; Rabbits ; Tetrazoles ; pharmacology ; Thromboplastin ; biosynthesis ; genetics ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

The effects of the combined use of angiotensin converting enzyme inhibitor (ACEI) benazepril and angiotensin II type 1 receptor antagonist (AT1RA) valsartan on apoptosis and the expression of apoptosis-related proteins Fas and FasL in the kidney of rats with adriamycin-induced nephritic glomerulosclerosis was investigated. Uninephrectomy and the injection of adriamycin induced the rat model of glomerulosclerosis. Benazepril (6 mg/kg), valsantan (20 mg/kg), or benazepril (3 mg/kg) plus valsantan (20 mg/kg) was respectively delivered daily by gavage to the rats in three treatment groups for 12 weeks. Apoptosis was examined by means of terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling (TUNEL). Immunohistochemistry was adopted to detect the expression of Fas and FasL. Software of pathological analysis quantitated the levels of Fas and FasL. The results showed that as compared with those in the control group, the kidneys in the model group had more severe glomerulosclerosis, much more apoptotic cells and higher levels of expression of Fas and FasL. The degree of glomerulosclerosis, the number of apoptotic cells and the levels of expression of Fas and FasL were reduced by benazepril and valsartan. The combined use of benazepril and valsartan had the best therapeutic effect. It was concluded that benazepril and valsartan could suppress the excessive apoptosis of kidney cells by lowering the expression of the apoptosis-related proteins Fas and FasL, so as to postpone the process of glomerulosclerosis. The combined use of benazepril and valsartan has better therapeutic effect.
Angiotensin II Type 1 Receptor Blockers ; administration & dosage ; Angiotensin-Converting Enzyme Inhibitors ; administration & dosage ; Animals ; Apoptosis ; drug effects ; Benzazepines ; administration & dosage ; Doxorubicin ; Drug Therapy, Combination ; Fas Ligand Protein ; Glomerulosclerosis, Focal Segmental ; chemically induced ; drug therapy ; pathology ; Kidney ; pathology ; Male ; Membrane Glycoproteins ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tetrazoles ; administration & dosage ; Tumor Necrosis Factors ; biosynthesis ; genetics ; Valine ; administration & dosage ; analogs & derivatives ; Valsartan ; fas Receptor ; biosynthesis ; genetics

OBJECTIVETo investigate the therapeutic effects of perindopril, an angiotensin-converting enzyme inhibitor, and valsartan, an angiotensin II receptor blocker on TGFbeta1 and TGFbeta receptor II mRNA, Smad3 and Smad7 on rat liver fibrosis.

METHODS60 Wistar rats were randomly divided into four groups (each group, n=15). Group 1 rats were not treated and served as healthy controls. The rats of groups 2,3,and 4 were injected with CCl(4) which induced liver fibrosis. After four weeks, group 3 rats started a treatment of perindopril, and group 4 rats with valsartan. All rats were sacrificed at the eighth week and their blood and livers were collected for analysis. The effects of perindopril and valsartan were evaluated by the levels of transforming growth factor-beta1 (TGFb1), and TGF receptor (TGFb1RII) mRNA in liver tissues by RT-PCR, the expressions and sites of TGFb1, Smad3 and Smad7 in liver tissue by immunohistochemical staining. The liver histopathology was also examined with HE staining, and the hydroxyproline in the liver and serum hyaluronic acid (HA) were examined using biochemsitry and RIA.

RESULTSCompared with the control group, the levels of TGFb1, TGFb1RII mRNA and the expression Smad3 were significantly decreased in the two treated groups, and the expression of Smad7 was also remarkably increased in the livers of rats treated with perindopril or valsartan. The histological changes of fibrosis, the hydroxyproline in the livers and HA were also improved in the treated rats.

CONCLUSIONPerindopril and valsartan have a protective effect on liver injury and can inhibit hepatic fibrosis induced by CCl(4) in rats. Their mechanisms may be associated with their effects of down-regulating TGFb1, TGFb1RII mRNA and smad3, and up-regulating Smad7 which then resulted in suppressing the activation of hepatic stellate cells.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Animals ; Carbon Tetrachloride ; Carbon Tetrachloride Poisoning ; Female ; Liver Cirrhosis, Experimental ; chemically induced ; metabolism ; Male ; Perindopril ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, Transforming Growth Factor beta ; biosynthesis ; genetics ; Smad3 Protein ; biosynthesis ; genetics ; Smad7 Protein ; biosynthesis ; genetics ; Tetrazoles ; pharmacology ; Transforming Growth Factor beta ; biosynthesis ; genetics ; Transforming Growth Factor beta1 ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

In industrial fermentation of amino acids the cells are often forced to synthesize the biochemicals excessive of their physiological needs. The knowledge of metabolic networks and their regulation relevant usually come from biochemical research, especially from enzymology, not from engineering study. To enrich the knowledge of metabolic sub-network of L-valine syntheses for higher production of L-valine, Corynebacterium glutamicum AS1.495 and its genetic derivatives AA361, AAT231, AATV341 were used for metabolic flux analysis. AS1.495 is a leucine auxotrophic (Leu-), and the three derivatives carry additional mutations. AA361 contains D-aspartic acid-beta-hydroxamate supersensitive marker (Leu-, L-AAHss), AAT231 (Leu-, L-AAHss, 2-TAr) is D-aspartic acid-beta-hydroxamate supersensitive and 2-thiazole alanine resistant, and AAT341 (Leu-, L-AAHss, 2-TAr, Vd-) is a D-aspartic acid-beta-hydroxamate supersensitive, 2-thiazole alanine resistant and valine-decompose-ability imperfect (Vd-). The concentrations of extra-cellular metabolites were determined under sub-steady-state of the batch culture. The metabolic flux distribution maps of the four strains were obtained, compared and analyzed. Our analysis showed that the flux ratio of EMP and HMP from the glucose-6-phosphate had increased from 0.205 in the parental strain AS1.495 to 0.321 in the multiple-mutation strain AATV341; the flux ratio of L-valine synthesis branch and the rest branches from the pyruvate node increased from 0.188 in AS1.495 to 3.29 in AATV341; the flux of lactic acid synthesis branch decreased from 11.1 in AS1.495 to 1.16 in AATV341; the flux of L-valine synthesis branch increased from 5.37 in AS1.495 to 37.3 in AATV341; and the productivity of L-valine correspondently increased from 4 g/L in AS1.495 to 24.5 g/L in AATV341. These results indicate that the introduction of analog supersensitive marker L-AAH55 and/or analog resistant marker 2-TAr skew the metabolic flux towards the formation of L-valine. This study revealed the usefulness of the metabolic flux analysis as a tool for verification of existing production strains. The analysis may play an important role in helping us b to rationally re-design metabolism for further improvement of fermentation process.
Corynebacterium glutamicum ; classification ; genetics ; metabolism ; Fermentation ; Glucose-6-Phosphate Isomerase ; metabolism ; Industrial Microbiology ; methods ; Mutation ; Pyruvic Acid ; metabolism ; Valine ; analysis ; biosynthesis

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Collagen Type I ; biosynthesis ; Hepatocytes ; cytology ; metabolism ; Tetrazoles ; pharmacology ; Valine ; analogs & derivatives ; pharmacology ; Valsartan