• Title/Summary/Keyword: de novo synthesis

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Secretion of the cloned serratia marcescens nuclease in escherichia coli (Serratia marcescens nuclease의 escherichia coli에서의 분비)

  • 신용철;이상열;김기석
    • Korean Journal of Microbiology
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    • v.28 no.4
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    • pp.297-303
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    • 1990
  • Secretion of Serratia marcescens nuclease by E. coli harboring pNUC4 was investigated. 29.2, 54.2 and 16.6% of total nuclease were observed in culture medium, periplasm, and cytoplasm of E. coli, respectively. To investigate the secretion mechanism of Serratia nuclease by E. coli, secretion kinetics of nuclease was examined in the presences of sodium azide, and energy metabolism inhibitor; procaine, an exoprotein processing inhibitor; and chloramphenicol, a protein synthesis inhibitor. In the presence of sodium azide, periplasmic unclease was gradually decreased and the extracellular nyclease was linearly increased according to the incubation time. Similar results were obtained in presences of procaine and chloramphenicol. From these results, we concluded that two transport processes are involved in nuclease secretion: secretion of nuclease through the inner membrane is occurred by an energy-dependent process and probably requiring precusor processing: secretion of nuclease through outer membrane does not require energy, de novo protein synthesis, and precursor processing.

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REGULATION OF PROENKEPHALIN GENE EXPRESSION AND MET-ENKEPHALIN SECRETION IN BOVINE ADRENAL MEDULLARY CHROMAFFIN CELLS AND C6 RAT GLIOMA CELLS

  • Suh, Hong-Won
    • Toxicological Research
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    • v.9 no.2
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    • pp.195-206
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    • 1993
  • The expression of proenkephalin (proENK) mRNA and Met-enkephalin (ME) secretion in C6 rat glioma cells and bovine adrenal medullary chromaffin (BAMC) cells were elucidated in the present study. The levels of proENK mRNA and ME secreted into the media in BAMC cells were measured in the presence of cycloheximide and 12-tetrade-canoylphorbol-13-acetate (TPA). Cycloheximide (20 nM) abolished the induction of proENK mRNA expression, protein synthesis and ME secretion by TPA (1nM), indicating that de novo protein synthesis was necessary for proENK gene expression and ME secretion.

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Protein Synthesis Pattern Analysis in the Regenerating Salamander Limb

  • Ju, Bong-Gun;Kim, Won-Sun
    • Animal cells and systems
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    • v.4 no.2
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    • pp.145-150
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    • 2000
  • Retinoic acid (RA) evokes pattern duplication in the regenerating salamander limb. Interestingly, it also enhances dedifferentiation in the regenerate by the morphological, histological and biochemical criteria. To examine whether there is any correlation between the RA-evoked pattern duplication and de novo protein synthetic profile in the regenerating salamander limb, especially during dedifferentiation, we analyzed stage-specific protein synthesis pattern in the normal and RA-treated regenerating limbs by metabolic labeling followed by two-dimensional gel electrophoresis. In the regenerating limbs without RA treatment, a few hundred kinds of proteins were found to be synthesized at the stage of wound healing and the total number of protein synthesized increased greatly as regeneration proceeded. The same trend was also observed in the RA-treated regenerating limbs. Interestingly, some protein spots were noted to be either newly synthesized or highly expressed by the RA treatment especially at the stage of dedifferentiation. The results shows that the enhancement of dedifferentiation state after the RA treatment correlates well with the protein synthesis profile, and suggest that those proteins are important for the RA-evoked pattern duplication in the regenerating limbs of salamander.

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Increased Hepatic Lipogenesis Elevates Liver Cholesterol Content

  • Berger, Jean-Mathieu;Moon, Young-Ah
    • Molecules and Cells
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    • v.44 no.2
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    • pp.116-125
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    • 2021
  • Cardiovascular diseases (CVDs) are the most common cause of death in patients with nonalcoholic fatty liver disease (NAFLD) and dyslipidemia is considered at least partially responsible for the increased CVD risk in NAFLD patients. The aim of the present study is to understand how hepatic de novo lipogenesis influences hepatic cholesterol content as well as its effects on the plasma lipid levels. Hepatic lipogenesis was induced in mice by feeding a fat-free/high-sucrose (FF/HS) diet and the metabolic pathways associated with cholesterol were then analyzed. Both liver triglyceride and cholesterol contents were significantly increased in mice fed an FF/HS diet. Activation of fatty acid synthesis driven by the activation of sterol regulatory element binding protein (SREBP)-1c resulted in the increased liver triglycerides. The augmented cholesterol content in the liver could not be explained by an increased cholesterol synthesis, which was decreased by the FF/HS diet. HMG-CoA reductase protein level was decreased in mice fed an FF/HS diet. We found that the liver retained more cholesterol through a reduced excretion of bile acids, a reduced fecal cholesterol excretion, and an increased cholesterol uptake from plasma lipoproteins. Very low-density lipoproteintriglyceride and -cholesterol secretion were increased in mice fed an FF/HS diet, which led to hypertriglyceridemia and hypercholesterolemia in Ldlr-/- mice, a model that exhibits a more human like lipoprotein profile. These findings suggest that dietary cholesterol intake and cholesterol synthesis rates cannot only explain the hypercholesterolemia associated with NAFLD, and that the control of fatty acid synthesis should be considered for the management of dyslipidemia.

PLANT BIOCHEMISTRY OF GINSENG SAPONINS(III) Radioactive Studies (2). Sodium Acetate-U-$C^{14}$ Experiment

  • The Korean Society of Ginseng The Korean Society of Ginseng
    • Proceedings of the Ginseng society Conference
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    • 1974.09a
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    • pp.101-113
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    • 1974
  • The radioactive compound sodium $acetate-U-C^{14}$ (C-14 acetate) was administered to two- and four-year-old July and September American ginseng (Panax quinquefolium L.) plants and cuttings. The C-14 acetate uptake was approximately $99\%.$ The autoradiochromatograms suggest that the saponins(panaquilins) isolated by preparative thin-layer chromatography contained impurities, especially those isolated from the leaf and stem extracts. The root and fruit methanol extracts yielded relatively pure saponins. The large amounts of panaquilin B and its proximity to panaquilin C on preparative thin-layer plates resulted in some admixing. The average concentration $(\%$ plant dry weight) of semipurified saponins were high in the leaves $(13.8\%),$ compared to fruits $(9.8\%),\;stems\;(7.9\%)\;and\;roots\;(6.3\%).$ The average percentage of C-14 acetate incorporation into panaquilins was $4.8\%.$ The average percentage of C-14 acetate incorporation into panaquilins B and C was higher $(1.40\%\;and\;1.13\%,$ respectively) than that into panaquilin C, (d), G-1 and G-2 $(0.75\%,\;0.65\%,\;0.13\%\;and\;0.53\%,$ respectively). Panaquilin synthesis may be depending upon the part collection period and age of the plant. The average percentage of C-14 acetate incorporation into panaquilin B is high in roots $(0.58\%)\;and\;stems\;(0.48\%);$ that into panaquilins C and (d) high in leaves $(0.40\%\;and\;0.45\%,$ respectively); and that into panaquilin E high in roots and leaves $(0.55\%\and\;0.50\%,$ respectively). Panaquilin G-2 was synthesized in all parts of plants. The panaquilins appear to be biosynthesized more actively in July than September (exception-panaquilin G-l). Panaquilins B, C and G-1 may be biosynthesized more actively in four-year-old plants and panaquilins (d) and E more actively in two-year-old plants. The results from expectance with cuttings suggest that the panaquilins are synthesized de novo in the above-ground parts of ginseng plants, and that panaquilin G-l may be synthesized de novo in the leaf. It is known from the tissue culture studies that panaquilins are produced by leaf, stem and root callus tissues and callus-root cultures of American and Korean ginseng plants. Panaquilins may actively be synthesized de novo in most any cell or organ of the ginseng plants. It was verified that C-14 acetate was incorporated into the panaxadiol portions of the panaquilins of two-year-old plants (sp. act., 0.56 $m{\mu}Ci/mg$) and four-year-old plants (sp. act., 0.54 $m{\mu}Ci/mg$).

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Identification of Potential Corynebacterium ammoniagenes Purine Gene Regulators Using the pur-lacZ Reporter in Escherichia coli

  • HAN , RI-NA;CHO, ICK-HYUN;CHUNG, SUNG-OH;HAN, JONG-KWON;LEE, JIN-HOO;KIM, SOO-KI;CHOI, KANG-YELL
    • Journal of Microbiology and Biotechnology
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    • v.14 no.6
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    • pp.1249-1255
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    • 2004
  • This study has developed Corynebacterium ammoniagenes (c. ammoniagenes) purine gene transcriptional reporters (purF-lacZ and purE-lacZ) that function in Escherichia coli (E. coli) DH5a. After transformation of a C. ammoniagenes gDNA library into E. coli cells harboring either purF-lacZ or purE-lacZ, C. ammoniagenes clones were obtained that repress purF-lacZ and purE-lacZ gene expression. The potential purE and purF regulatory genes are homologous to the genes encoding transcription regulators, the regulatory subunit of RNA polymerase, and genes for purine nucleotide biosynthesis of various bacteria. The C. ammoniagenes purE-lacZ and purF-lacZ reporters were repressed by adenine and guanine within E. coli, indicating similarity in the regulatory mechanism of purine biosynthesis in C. ammoniagenes and E. coli. Gene regulation of pur-lacZ by adenine and guanine was partly abolished in cells expressing potential purine regulatory genes, indicating functionality of the purine gene regulators in repression of purE-lacZ and purF-lacZ. The purE-lacZ and purF-lacZ reporters can be used for the screening of genes involved in the regulation of the de novo synthesis of the purine nucleotides.

RNA-Seq De Novo Assembly and Differential Transcriptome Analysis of Korean Medicinal Herb Cirsium japonicum var. spinossimum

  • Roy, Neha Samir;Kim, Jung-A;Choi, Ah-Young;Ban, Yong-Wook;Park, Nam-Il;Park, Kyong-Cheul;Yang, Hee-sun;Choi, Ik-Young;Kim, Soonok
    • Genomics & Informatics
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    • v.16 no.4
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    • pp.34.1-34.9
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    • 2018
  • Cirsium japonicum belongs to the Asteraceae or Compositae family and is a medicinal plant in Asia that has a variety of effects, including tumour inhibition, improved immunity with flavones, and antidiabetic and hepatoprotective effects. Silymarin is synthesized by 4-coumaroyl-CoA via both the flavonoid and phenylpropanoid pathways to produce the immediate precursors taxifolin and coniferyl alcohol. Then, the oxidative radicalization of taxifolin and coniferyl alcohol produces silymarin. We identified the expression of genes related to the synthesis of silymarin in C. japonicum in three different tissues, namely, flowers, leaves, and roots, through RNA sequencing. We obtained 51,133 unigenes from transcriptome sequencing by de novo assembly using Trinity v2.1.1, TransDecoder v2.0.1, and CD-HIT v4.6 software. The differentially expressed gene analysis revealed that the expression of genes related to the flavonoid pathway was higher in the flowers, whereas the phenylpropanoid pathway was more highly expressed in the roots. In this study, we established a global transcriptome dataset for C. japonicum. The data shall not only be useful to focus more deeply on the genes related to product medicinal metabolite including flavolignan but also to study the functional genomics for genetic engineering of C. japonicum.

Rapamycin Inhibits Expression of Elongation of Very-long-chain Fatty Acids 1 and Synthesis of Docosahexaenoic Acid in Bovine Mammary Epithelial Cells

  • Guo, Zhixin;Wang, Yanfeng;Feng, Xue;Bao, Chaogetu;He, Qiburi;Bao, Lili;Hao, Huifang;Wang, Zhigang
    • Asian-Australasian Journal of Animal Sciences
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    • v.29 no.11
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    • pp.1646-1652
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    • 2016
  • Mammalian target of rapamycin complex 1 (mTORC1) is a central regulator of cell growth and metabolism and is sufficient to induce specific metabolic processes, including de novo lipid biosynthesis. Elongation of very-long-chain fatty acids 1 (ELOVL1) is a ubiquitously expressed gene and the product of which was thought to be associated with elongation of carbon (C) chain in fatty acids. In the present study, we examined the effects of rapamycin, a specific inhibitor of mTORC1, on ELOVL1 expression and docosahexaenoic acid (DHA, C22:6 n-3) synthesis in bovine mammary epithelial cells (BMECs). We found that rapamycin decreased the relative abundance of ELOVL1 mRNA, ELOVL1 expression and the level of DHA in a time-dependent manner. These data indicate that ELOVL1 expression and DHA synthesis are regulated by mTORC1 in BMECs.

Effects of Cadmium on Heat Shock Protein Induction and on Clinical Indices in Rats (카드뮴이 랫드의 Heat Shock Protein 발현에 미치는 영향과 독성학적 변화에 관한 연구)

  • 김판기
    • Journal of Environmental Health Sciences
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    • v.22 no.4
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    • pp.91-101
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    • 1996
  • Exposure indices are important tools which enable scientists to reliably predict and detect exposures to xenobiotics and resultant cell injury. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of toxicant-induced changes in gene expression, i.e. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and toxicity. The acute and chronic effects of cadmium(Cd, $CdCl_2$ 20 mg/kg) on Wistar male rats were evaluated concerning cadmium contents, tissues enzyme activity, HSP expression. The results of the study were as follows: 1. Less cadmium was absorbed through the digestive tracts, but the ratio of contents in renal to hepatic cadmium was higher at 8 weeks after treatment. 2. ALT(alanine aminotransferase), AST(aspartate aminotransferase), glucose, BUN(blood urea nitrogen), creatinine, the key indices of the clinical changes in hepatic and renal function were significantly changed by the cadmium treatment after 1 week in liver, after 4 weeks in kidney. 3. Enhanced synthesis of 70 KDa relative molecular mass proteins were detected in 2 hours after cadmium exposure, with maximum activity occurring at 8~48 hours. Induction of $HSP_{70}$ was evident at proximal tubules and glomeruli in kidney. Testicular cells produced enough HSP to be detected normally. From the above results, it could be concluded that $HSP_{70}$ induction by the cadmium treatment was a rapid reaction to indicate the exposure of xenobiotics.

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Regulatory Mechanism of Lipopolysaccharide(LPS)-Induced Interleukin-8 Gene Expression in Mononuclear Phagocytic Cells (단핵식세포에서 내독소에 의한 인터루킨-8 유전자 발현 조절기전에 관한 연구)

  • Yoo, Chul-Gyu;Suh, Gee-Young;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
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    • v.41 no.5
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    • pp.462-474
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    • 1994
  • Background : In acute lung injury, activated neutrophils play an important role in tissue damage. For neutrophils to participate in lung inflammation, chemotactic factors released from mononuclear phagocytes are needed to bring these cells to the local site of inflammation, with interleukin-8 (IL-8) being one of the most specific and important chemotactic factors for neutrophils. IL-8 also induces the expression of adhesion molecules and activates neutrophils to release various inflammatory mediators. Lipopolysaccharide(LPS) is one of the most important causes of adult respiratory distress syndrome and can cause release of many inflammatory cytokines including IL-8 leading to acute lung injury. But little is known about the regulatory mechanism of LPS-induced IL-8 gene expression in mononuclear phagocytes. Method : Human alveolar macrophages(HAM) and peripleral blood monocytes(PBMC) were isolated from healthy volunteers. Time and dose relationship of LPS-induced IL-8 mRNA expression was observed by Northern blot analysis. To evaluate the regulatory mechanism of LPS-induced IL-8 gene expression, pretreatment of actinomycin D(AD, $5{\mu}g/ml$) and cycloheximide(CHX, $5{\mu}g/ml$) was done and Northern blot analysis for IL-8 mRNA and ELISA for immunoreactive IL-8 protein in culture supernatant were performed. Results : 1) In HAM, dose and time dependent LPS-induced IL-8 mRNA expression was observed with peak mRNA level at 8 hours post-stimulation. 2) In PBMC, dose and time dependent LPS-induced IL-8 mRNA expression was also observed with peak mRNA level at 4 hours post-stimulation. 3) AD decreased expression of LPS-induced IL-8 gene expression at both mRNAand protein levels in both types of cells. 4) CHX decreased expression of LPS-induced IL-8 gene expression at protein level in both cell types but in HAM, superinduction of IL-8 mRNA was observed while decreased expression of IL-8 mRNA was observed in PBMC. Conclusion : Time and dose dependent LPS-induced IL-8 gene expression was observed in mononuclear phagocytes which is at least partly regulated pretranslationally. LPS-induced IL-8 mRNA expression in HAM needs no de novo protein synthesis and may be under the control of a labile repressor protein while de novo protein synthesis may be needed in PBMC.

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