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Sample records for biosynthesis sarkosyl neocarzinostatin

  1. Obtaining Soluble Folded Proteins from Inclusion Bodies Using Sarkosyl, Triton X-100, and CHAPS: Application to LB and M9 Minimal Media.

    Science.gov (United States)

    Massiah, Michael A; Wright, Katharine M; Du, Haijuan

    2016-04-01

    This unit describes a straightforward and efficient method of using sarkosyl to solubilize and recover difficult recombinant proteins, such as GST- and His6 -tagged fusion proteins, that are overexpressed in E. coli. This protocol is especially useful for rescuing recombinant proteins overexpressed in M9 minimal medium. Sarkosyl added to lysis buffers helps with both protein solubility and cell lysis. Higher percentage sarkosyl (up to 10%) can extract >95% of soluble protein from inclusion bodies. In the case of sarkosyl-solubilized GST-fusion proteins, batch-mode affinity purification requires addition of a specific ratio of Triton X-100 and CHAPS, while sarkosyl-solubilized His6 -tagged fusion proteins can be directly purified on Ni(2+) resin columns. Proteins purified by this method could be widely used in biological assays, structure analysis and mass spectrum assay.

  2. Radiotherapy combined with aclarubicin and neocarzinostatin for cancer of the gallbladder

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, Shin-ichi; Mishina, Hitoshi; Funaki, Ken-ichi; Mori, Toshihiko (Tohoku Rosai Hospital, Sendai (Japan))

    1991-03-01

    Cancer of the gallbladder is radioresistant. When it was found inoperable, she was subjected to radiotherapy combined with aclarubicin and neocarzinostatin. Therapeutic effectiveness was confirmed at autopsy as she later succumbed to uterine cervical cancer. Thus, the present radiochemotherapeutic regimen would probably provide a means of overcoming those radioresistant inoperable malignancies. Intravenous administrations of appropriate antibiotics such as azthreonam and reniran may probably be helpful in the prevention and treatment of septic peritonitis possible during the course of reinforced radiotherapy of the abdomen. (author).

  3. Construction of a genetically engineered chimeric apoprotein consisting of sequences derived from lidamycin and neocarzinostatin.

    Science.gov (United States)

    Jiang, Wenguo; Shang, Boyang; Li, Liang; Zhang, Shenghua; Zhen, Yongsu

    2016-01-01

    Neocarzinostatin (NCS) consists of an enediyne chromophore and an apoprotein (NCP). Lidamycin (LDM) is composed of another active enediyne chromophore (AE) and an acidic protein (LDP). Although the structures of NCP and LDP are very similar, LDM has been shown to have an increased tumor-suppressive activity than that of NCS. The aim of this study was to construct a chimeric protein (CMP) that consists of both the terminus residue of NCP and an LDP pocket-forming residue that can bind AE. This CMP will have a structure similar to NCS and an antitumor activity similar to LDM. The assembling efficiency of LDP, CMP, and NCP was 73.9, 1.5, and 1.1%, respectively. The cytotoxicity was consistent with their assembling efficiency of AE in proteins. When CMP-AE and NCP-AE were administered at equivalent AE doses of LDM, the inhibition rate of CMP-AE was the same as LDM and significantly higher than that of NCP-AE. Our study implied that the binding activity between LDP and AE was very specific. The terminus residue of LDP could affect the specifically binding activity. The pocket-forming residue could confer a protective function to the chromophore. Further investigation of its bioactivity might serve as a new drug design strategy and drug-delivery carrier in targeted cancer therapy.

  4. Aflatoxin biosynthesis: current frontiers.

    Science.gov (United States)

    Roze, Ludmila V; Hong, Sung-Yong; Linz, John E

    2013-01-01

    Aflatoxins are among the principal mycotoxins that contaminate economically important food and feed crops. Aflatoxin B1 is the most potent naturally occurring carcinogen known and is also an immunosuppressant. Occurrence of aflatoxins in crops has vast economic and human health impacts worldwide. Thus, the study of aflatoxin biosynthesis has become a focal point in attempts to reduce human exposure to aflatoxins. This review highlights recent advances in the field of aflatoxin biosynthesis and explores the functional connection between aflatoxin biosynthesis, endomembrane trafficking, and response to oxidative stress. Dissection of the regulatory mechanisms involves a complete comprehension of the aflatoxin biosynthetic process and the dynamic network of transcription factors that orchestrates coordinated expression of the target genes. Despite advancements in the field, development of a safe and effective multifaceted approach to solve the aflatoxin food contamination problem is still required.

  5. BIOSYNTHESIS OF YEAST CAROTENOIDS

    Science.gov (United States)

    Simpson, Kenneth L.; Nakayama, T. O. M.; Chichester, C. O.

    1964-01-01

    Simpson, Kenneth L. (University of California, Davis), T. O. M. Nakayama, and C. O. Chichester. Biosynthesis of yeast carotenoids. J. Bacteriol. 88:1688–1694. 1964.—The biosynthesis of carotenoids was followed in Rhodotorula glutinis and in a new strain, 62-506. The treatment of the growing cultures by methylheptenone, or ionone, vapors permitted observations of the intermediates in the biosynthetic pathway. On the basis of concentration changes and accumulation in blocked pathways, the sequence of carotenoid formation is postulated as phytoene, phytofluene, ζ-carotene, neurosporene, β-zeacarotene, γ-carotene, torulin, a C40 aldehyde, and torularhodin. Torulin and torularhodin were established as the main carotenoids of 62-506. PMID:14240958

  6. Xyloglucan and its biosynthesis

    Directory of Open Access Journals (Sweden)

    Olga A Zabotina

    2012-06-01

    Full Text Available The hemicellulosic polysaccharide xyloglucan (XyG, found in the primary cell walls of most plant tissues, is important for structural organization of the cell wall and regulation of growth and development. Significant recent progress in structural characterization of XyGs from different plant species has shed light on the diversification of XyG during plant evolution. Also, identification of XyG biosynthetic enzymes and examination of their interactions suggests the involvement of a multiprotein complex in XyG biosynthesis. This mini-review presents an updated overview of the diversity of XyG structures in plant taxa and recent findings on XyG biosynthesis.

  7. Upstream regulation of mycotoxin biosynthesis.

    Science.gov (United States)

    Alkhayyat, Fahad; Yu, Jae-Hyuk

    2014-01-01

    Mycotoxins are natural contaminants of food and feed products, posing a substantial health risk to humans and animals throughout the world. A plethora of filamentous fungi has been identified as mycotoxin producers and most of these fungal species belong to the genera Aspergillus, Fusarium, and Penicillium. A number of studies have been conducted to better understand the molecular mechanisms of biosynthesis of key mycotoxins and the regulatory cascades controlling toxigenesis. In many cases, the mycotoxin biosynthetic genes are clustered and regulated by one or more pathway-specific transcription factor(s). In addition, as biosynthesis of many secondary metabolites is coordinated with fungal growth and development, there are a number of upstream regulators affecting biosynthesis of mycotoxins in fungi. This review presents a concise summary of the regulation of mycotoxin biosynthesis, focusing on the roles of the upstream regulatory elements governing biosynthesis of aflatoxin and sterigmatocystin in Aspergillus.

  8. Microbial biosynthesis of alkanes.

    Science.gov (United States)

    Schirmer, Andreas; Rude, Mathew A; Li, Xuezhi; Popova, Emanuela; del Cardayre, Stephen B

    2010-07-30

    Alkanes, the major constituents of gasoline, diesel, and jet fuel, are naturally produced by diverse species; however, the genetics and biochemistry behind this biology have remained elusive. Here we describe the discovery of an alkane biosynthesis pathway from cyanobacteria. The pathway consists of an acyl-acyl carrier protein reductase and an aldehyde decarbonylase, which together convert intermediates of fatty acid metabolism to alkanes and alkenes. The aldehyde decarbonylase is related to the broadly functional nonheme diiron enzymes. Heterologous expression of the alkane operon in Escherichia coli leads to the production and secretion of C13 to C17 mixtures of alkanes and alkenes. These genes and enzymes can now be leveraged for the simple and direct conversion of renewable raw materials to fungible hydrocarbon fuels.

  9. Engineering of Glucosinolate Biosynthesis

    DEFF Research Database (Denmark)

    Møldrup, Morten Emil; Salomonsen, Bo; Halkier, Barbara Ann

    2012-01-01

    -efficient methods for identification and validation of candidate genes are needed. This chapter covers the methodology we are using for gene discovery in glucosinolate engineering, namely, guilt-by-association-based in silico methods and fast proof-of-function screens by transient expression in Nicotiana...... of glucosinolate biosynthesis, although in planta validation of candidate gene function often is hampered by time-consuming generation of knockout and overexpression lines in Arabidopsis. To better exploit the increasing amount of data available from genomic sequencing, microarray database and RNAseq, time...... benthamiana. Moreover,the lessons learned in the rapid, transient tobacco system are readily translated to our robust, versatile yeast expression platform, where additional genes critical for large-scale microbial production of glucosinolates can be identified. We anticipate that the methodology presented...

  10. The regulation of ascorbate biosynthesis.

    Science.gov (United States)

    Bulley, Sean; Laing, William

    2016-10-01

    We review the regulation of ascorbate (vitamin C) biosynthesis, focusing on the l-galactose pathway. We discuss the regulation of ascorbate biosynthesis at the level of gene transcription (both repression and enhancement) and translation (feedback inhibition of translation by ascorbate concentration) and discuss the eight proteins that have been demonstrated to date to affect ascorbate concentration in plant tissues. GDP-galactose phosphorylase (GGP) and GDP-mannose epimerase are critical steps that regulate ascorbate biosynthesis. These and other biosynthetic genes are controlled at the transcriptional level, while GGP is also controlled at the translational level. Ascorbate feedback on enzyme activity has not been observed unequivocally.

  11. Diverse inhibitors of aflatoxin biosynthesis.

    Science.gov (United States)

    Holmes, Robert A; Boston, Rebecca S; Payne, Gary A

    2008-03-01

    Pre-harvest and post-harvest contamination of maize, peanuts, cotton, and tree nuts by members of the genus Aspergillus and subsequent contamination with the mycotoxin aflatoxin pose a widespread food safety problem for which effective and inexpensive control strategies are lacking. Since the discovery of aflatoxin as a potently carcinogenic food contaminant, extensive research has been focused on identifying compounds that inhibit its biosynthesis. Numerous diverse compounds and extracts containing activity inhibitory to aflatoxin biosynthesis have been reported. Only recently, however, have tools been available to investigate the molecular mechanisms by which these inhibitors affect aflatoxin biosynthesis. Many inhibitors are plant-derived and a few may be amenable to pathway engineering for tissue-specific expression in susceptible host plants as a defense against aflatoxin contamination. Other compounds show promise as protectants during crop storage. Finally, inhibitors with different modes of action could be used in comparative transcriptional and metabolomic profiling experiments to identify regulatory networks controlling aflatoxin biosynthesis.

  12. Auxin biosynthesis and storage forms.

    Science.gov (United States)

    Korasick, David A; Enders, Tara A; Strader, Lucia C

    2013-06-01

    The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development.

  13. Transcription factors in alkaloid biosynthesis.

    Science.gov (United States)

    Yamada, Yasuyuki; Sato, Fumihiko

    2013-01-01

    Higher plants produce a large variety of low-molecular weight secondary compounds. Among them, nitrogen-containing alkaloids are the most biologically active and are often used pharmaceutically. Whereas alkaloid chemistry has been intensively investigated, alkaloid biosynthesis, including the relevant biosynthetic enzymes, genes and their regulation, and especially transcription factors, is largely unknown, as only a limited number of plant species produce certain types of alkaloids and they are difficult to study. Recently, however, several groups have succeeded in isolating the transcription factors that are involved in the biosynthesis of several types of alkaloids, including bHLH, ERF, and WRKY. Most of them show Jasmonate (JA) responsiveness, which suggests that the JA signaling cascade plays an important role in alkaloid biosynthesis. Here, we summarize the types and functions of transcription factors that have been isolated in alkaloid biosynthesis, and characterize their similarities and differences compared to those in other secondary metabolite pathways, such as phenylpropanoid and terpenoid biosyntheses. The evolution of this biosynthetic pathway and regulatory network, as well as the application of these transcription factors to metabolic engineering, is discussed.

  14. Biosynthesis and transport of terpenes

    NARCIS (Netherlands)

    Ting, H.M.

    2014-01-01

    Terpenoids are the largest class of natural product that are produced by plants, with functions that range from a role in plant development to direct defence against pathogens and indirect defence against insects through the attraction of natural enemies. While terpene biosynthesis genes have been w

  15. (-)-Menthol biosynthesis and molecular genetics

    Science.gov (United States)

    Croteau, Rodney B.; Davis, Edward M.; Ringer, Kerry L.; Wildung, Mark R.

    2005-12-01

    (-)-Menthol is the most familiar of the monoterpenes as both a pure natural product and as the principal and characteristic constituent of the essential oil of peppermint ( Mentha x piperita). In this paper, we review the biosynthesis and molecular genetics of (-)-menthol production in peppermint. In Mentha species, essential oil biosynthesis and storage is restricted to the peltate glandular trichomes (oil glands) on the aerial surfaces of the plant. A mechanical method for the isolation of metabolically functional oil glands, has provided a system for precursor feeding studies to elucidate pathway steps, as well as a highly enriched source of the relevant biosynthetic enzymes and of their corresponding transcripts with which cDNA libraries have been constructed to permit cloning and characterization of key structural genes. The biosynthesis of (-)-menthol from primary metabolism requires eight enzymatic steps, and involves the formation and subsequent cyclization of the universal monoterpene precursor geranyl diphosphate to the parent olefin (-)-(4 S)-limonene as the first committed reaction of the sequence. Following hydroxylation at C3, a series of four redox transformations and an isomerization occur in a general “allylic oxidation-conjugate reduction” scheme that installs three chiral centers on the substituted cyclohexanoid ring to yield (-)-(1 R, 3 R, 4 S)-menthol. The properties of each enzyme and gene of menthol biosynthesis are described, as are their probable evolutionary origins in primary metabolism. The organization of menthol biosynthesis is complex in involving four subcellular compartments, and regulation of the pathway appears to reside largely at the level of gene expression. Genetic engineering to up-regulate a flux-limiting step and down-regulate a side route reaction has led to improvement in the composition and yield of peppermint oil.

  16. Gibberellin biosynthesis in Gibberlla fujikuroi

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, S.W.; Coolbaugh, R.C. (Iowa State Univ., Ames (USA))

    1989-04-01

    Gibberellins (GAs) are a group of plant growth hormones which were first isolated from the fungus Gibberella fujikuori. We have examined the biosynthesis of GAs in this fungus in liquid cultures using HPLC followed by GC-MS. Furthermore we have used cell-free enzyme extracts with {sup 14}C-labeled intermediates to examine the regulation of specific parts of the biosynthetic pathway. GA{sub 3} is the predominant GA in well aerated cultures. GA{sub 4} and GA{sub 7}, intermediates in GA{sub 3} biosynthesis, accumulate in cultures with low levels of dissolved oxygen, but are not detectable in more aerated cultures. Light stimulates GA production in G. fujikuroi cultures grown from young stock. Cell-free enzyme studies indicate that light has no effect on incorporation of mevalonic acid into kaurene, but does significantly stimulate the oxidation of kaurenoic acid.

  17. Lignin biosynthesis and its molecular regulation

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Lignin biosynthesis has become increasingly highlighted because it plays an important role in the growth and development of plant, in the systematic evolution of plant and in the human life. Due to the progress in the field of lignin studies in recent years, the lignin biosynthesis pathway has been 修订日期:. Here we discuss some genetic engineering approaches on lignin biosynthesis, and conceive strategy to regulate lignin biosynthesis in order to use lignin resource more efficiently in agricultural and industrial productions.

  18. Glucosinolate biosynthesis in Eruca sativa.

    Science.gov (United States)

    Katsarou, Dimitra; Omirou, Michalis; Liadaki, Kalliopi; Tsikou, Daniela; Delis, Costas; Garagounis, Constantine; Krokida, Afrodite; Zambounis, Antonis; Papadopoulou, Kalliope K

    2016-12-01

    Glucosinolates (GSLs) are a highly important group of secondary metabolites in the Caparalles order, both due to their significance in plant-biome interactions and to their chemoprotective properties. This study identified genes involved in all steps of aliphatic and indolic GSL biosynthesis in Eruca sativa, a cultivated plant closely related to Arabidopsis thaliana with agronomic and nutritional value. The impact of nitrogen (N) and sulfur (S) availability on GSL biosynthetic pathways at a transcriptional level, and on the final GSL content of plant leaf and root tissues, was investigated. N and S supply had a significant and interactive effect on the GSL content of leaves, in a structure-specific and tissue-dependent manner; the metabolites levels were significantly correlated with the relative expression of the genes involved in their biosynthesis. A more complex effect was observed in roots, where aliphatic and indolic GSLs and related biosynthetic genes responded differently to the various nutritional treatments suggesting that nitrogen and sulfur availability are important factors that control plant GSL content at a transcriptional level. The biological activity of extracts derived from these plants grown under the specific nutritional schemes was examined. N and S availability were found to significantly affect the cytotoxicity of E. sativa extracts on human cancer cells, supporting the notion that carefully designed nutritional schemes can promote the accumulation of chemoprotective substances in edible plants.

  19. Steroid biosynthesis in adipose tissue.

    Science.gov (United States)

    Li, Jiehan; Papadopoulos, Vassilios; Vihma, Veera

    2015-11-01

    Tissue-specific expression of steroidogenic enzymes allows the modulation of active steroid levels in a local manner. Thus, the measurement of local steroid concentrations, rather than the circulating levels, has been recognized as a more accurate indicator of the steroid action within a specific tissue. Adipose tissue, one of the largest endocrine tissues in the human body, has been established as an important site for steroid storage and metabolism. Locally produced steroids, through the enzymatic conversion from steroid precursors delivered to adipose tissue, have been proven to either functionally regulate adipose tissue metabolism, or quantitatively contribute to the whole body's steroid levels. Most recently, it has been suggested that adipose tissue may contain the steroidogenic machinery necessary for the initiation of steroid biosynthesis de novo from cholesterol. This review summarizes the evidence indicating the presence of the entire steroidogenic apparatus in adipose tissue and discusses the potential roles of local steroid products in modulating adipose tissue activity and other metabolic parameters.

  20. Acylphloroglucinol Biosynthesis in Strawberry Fruit.

    Science.gov (United States)

    Song, Chuankui; Ring, Ludwig; Hoffmann, Thomas; Huang, Fong-Chin; Slovin, Janet; Schwab, Wilfried

    2015-11-01

    Phenolics have health-promoting properties and are a major group of metabolites in fruit crops. Through reverse genetic analysis of the functions of four ripening-related genes in the octoploid strawberry (Fragaria × ananassa), we discovered four acylphloroglucinol (APG)-glucosides as native Fragaria spp. fruit metabolites whose levels were differently regulated in the transgenic fruits. The biosynthesis of the APG aglycones was investigated by examination of the enzymatic properties of three recombinant Fragaria vesca chalcone synthase (FvCHS) proteins. CHS is involved in anthocyanin biosynthesis during ripening. The F. vesca enzymes readily catalyzed the condensation of two intermediates in branched-chain amino acid metabolism, isovaleryl-Coenzyme A (CoA) and isobutyryl-CoA, with three molecules of malonyl-CoA to form phlorisovalerophenone and phlorisobutyrophenone, respectively, and formed naringenin chalcone when 4-coumaroyl-CoA was used as starter molecule. Isovaleryl-CoA was the preferred starter substrate of FvCHS2-1. Suppression of CHS activity in both transient and stable CHS-silenced fruit resulted in a substantial decrease of APG glucosides and anthocyanins and enhanced levels of volatiles derived from branched-chain amino acids. The proposed APG pathway was confirmed by feeding isotopically labeled amino acids. Thus, Fragaria spp. plants have the capacity to synthesize pharmaceutically important APGs using dual functional CHS/(phloriso)valerophenone synthases that are expressed during fruit ripening. Duplication and adaptive evolution of CHS is the most probable scenario and might be generally applicable to other plants. The results highlight that important promiscuous gene function may be missed when annotation relies solely on in silico analysis.

  1. Monoterpene biosynthesis potential of plant subcellular compartments

    NARCIS (Netherlands)

    Dong, L.; Jongedijk, E.J.; Bouwmeester, H.J.; Krol, van der A.R.

    2016-01-01

    Subcellular monoterpene biosynthesis capacity based on local geranyl diphosphate (GDP) availability or locally boosted GDP production was determined for plastids, cytosol and mitochondria. A geraniol synthase (GES) was targeted to plastids, cytosol, or mitochondria. Transient expression in Nicotiana

  2. Biosynthesis and Genetic Engineering of Polyketides

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiang-Cheng; WANG Qiao-Mei; SHEN Yue-Mao; DU Liang-Cheng; HUFFMAN Justin; GERBER Ryan; LOU Li-Li; XIE Yun-Xuan; LIN Ting; JORGENSON Joel; MARESCH Andrew; VOGELER Chad

    2008-01-01

    Polyketides are one of the largest groups of natural products produced by bacteria, fungi, and plants. Many of these metabolites have highly complex chemical structures and very important biological activities, including antibiotic, anticancer, immunosuppressant, and anti-cholesterol activities. In the past two decades, extensive investigations have been carried out to understand the molecular mechanisms for polyketide biosynthesis. These efforts have led to the development of various rational approaches toward engineered biosynthesis of new polyketides. More recently, the research efforts have shifted to the elucidation of the three-dimentional structure of the complex enzyme machineries for polyketide biosynthesis and to the exploitation of new sources for polyketide production, such as filamentous fungi and marine microorganisms. This review summarizes our general understanding of the biosynthetic mechanisms and the progress in engineered biosynthesis of polyketides.

  3. Sterols of the fungi - Distribution and biosynthesis

    Science.gov (United States)

    Weete, J. D.

    1973-01-01

    The importance of sterols in the growth and reproduction in fungi is becoming increasingly apparent. This article concerns the composition and biosynthesis of ergosterol in these organisms. Comparison to plant and animal sterol formation are made.

  4. Insulin biosynthesis and diabetes mellitus.

    Science.gov (United States)

    Permutt, A; Chirgwin, J; Giddings, S; Kakita, K; Rotwein, P

    1981-10-01

    This review reports the use of recombinant DNA techniques in the study of the structure and regulation of expression of insulin genes in man and experimental animals. Insulin biosynthesis by pancreatic islet cells is predominantly regulated by change in plasma glucose concentration. Using a cell-free protein synthesizing system as an assay of functional proinsulin messenger RNA (mRNA), and hybridization analysis with a cloned DNA complementary to proinsulin mRNA, it has been determined that through changes in proinsulin mRNA levels. Insulin genes of the rat, chicken and human have been isolated and sequenced. The 5' ends of the genes have similar sequences suggesting areas important for regulation of transcription. There are two non-allelic insulin genes in the rat, but only one in chickens and humans. Intervening sequences, areas of DNA transcribed into precursor mRNA but which do not appear in mature mRNA, have been described within insulin genes. The insulin gene resides on chromosome 11 of humans as determined by DNA hybridization analysis of mouse human hybrid cells. The structure of the insulin gene in genomic DNA of humans has been analyzed in diabetics and non-diabetics. Insertions of DNA between 1500 and 3400 base pairs have been detected near the transcription initiation site in 65% of type II diabetics, and 25-30% of non-diabetics (this difference is significant at the p less than 0.001 level). Limitation of these insertions to this potential promotor region of the insulin gene suggests that they may alter gene expression in type II diabetes. These insertions of DNA may prove to be useful genetic markers for diabetes.

  5. Biosynthesis of gold nanoparticles: A green approach.

    Science.gov (United States)

    Ahmed, Shakeel; Annu; Ikram, Saiqa; Yudha S, Salprima

    2016-08-01

    Nanotechnology is an immensely developing field due to its extensive range of applications in different areas of technology and science. Different types of methods are employed for synthesis of nanoparticles due to their wide applications. The conventional chemical methods have certain limitations with them either in the form of chemical contaminations during their syntheses procedures or in later applications and use of higher energy. During the last decade research have been focussed on developing simple, clean, non-toxic, cost effective and eco-friendly protocols for synthesis of nanoparticles. In order to get this objective, biosynthesis methods have been developed in order to fill this gap. The biosynthesis of nanoparticles is simple, single step, eco-friendly and a green approach. The biochemical processes in biological agents reduce the dissolved metal ions into nano metals. The various biological agents like plant tissues, fungi, bacteria, etc. are used for biosynthesis for metal nanoparticles. In this review article, we summarised recent literature on biosynthesis of gold nanoparticles which have revolutionised technique of synthesis for their applications in different fields. Due to biocompatibility of gold nanoparticles, it has find its applications in biomedical applications. The protocol and mechanism of biosynthesis of gold nanoparticles along with various applications have also been discussed.

  6. Flavonoids: Biosynthesis, Biological functions and Biotechnological applications

    Directory of Open Access Journals (Sweden)

    Maria Lorena eFalcone Ferreyra

    2012-09-01

    Full Text Available Flavonoids are widely distributed secondary metabolites with different metabolic functions in plants. The elucidation of the biosynthetic pathways, as well as their regulation by MYB, bHLH and WD40-type transcription factors, has allowed metabolic engineering of plants through the manipulation of the different final products with valuable applications. The present review describes the regulation of flavonoid biosynthesis, as well as the biological functions of flavonoids in plants, such as in defense against UV-B radiation and pathogen infection, nodulation, pollen fertility. In addition, we discuss different strategies and achievements through the genetic engineering of flavonoid biosynthesis with implication in the industry and the combinatorial biosynthesis in microorganisms by the reconstruction of the pathway to obtain high amounts of specific compounds.

  7. The Spatial Organization of Glucosinolate Biosynthesis

    DEFF Research Database (Denmark)

    Nintemann, Sebastian

    . However, questions concerning the spatial arrangement of the glucosinolate biosynthetic machinery and the consequential distribution of the metabolites remain. Different types of glucosinolates require specialized enzymes for certain steps in their biosynthetic pathways and whether these act in the same...... cells is an open question. Likewise, it is not known how glucosinolate biosynthesis is orchestrated at the subcellular level. These open questions were addressed with several approaches in this project, with the aim of shedding light on the spatial organization of glucosinolate biosynthesis from...... between the individual classes of glucosinolates under constitutive and induced conditions and identified the source tissues of these defense compounds. Protein-protein interaction studies were carried out to investigate the subcellular organization of glucosinolate biosynthesis. We identified a family...

  8. The Terpenoid Biosynthesis Toolkit of Trichoderma.

    Science.gov (United States)

    Bansal, Ravindra; Mukherjee, Prasun Kumar

    2016-04-01

    The widely used biotechnologically important fungi belonging to the genus Trichoderma are rich sources of secondary metabolites. Even though the genomes of several Trichoderma spp. have been published, and data are available on the genes involved in biosynthesis of non-ribosomal peptide synthetases and polyketide synthases, no genome-wide data are available for the terpenoid biosynthesis machinery in these organisms. In the present study, we have identified the genes involved in terpene biosynthesis in the genomes of three Trichoderma spp., viz., T. virens, T. atroviride and T. reesei. While the genes involved in the condensation steps are highly conserved across the three species, these fungi differed in the number and organization of terpene cyclases. T. virens genome harbours eleven terpene cyclases, while T. atroviride harbours seven, and T. reeseisix in their genomes; seven, three and two being part of putative secondary metabolism related gene clusters.

  9. Triterpenoid biosynthesis in Euphorbia lathyris latex

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, D.R.

    1987-11-01

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I/sub 50/ concentration of 3.2 ..mu..M. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I/sub 50/ of 4 ..mu..M. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4-/sup 3/H-mevalonic acid and incubating latex with a mixture of this and /sup 14/C-mevalonic acid. From the /sup 3/H//sup 14/C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs.

  10. Erythrocentaurin, Biosynthesis Postulation and Biomimetic Synthesis

    Institute of Scientific and Technical Information of China (English)

    LEI,Jun; YUAN,Xiang-Hui; LIU,Zhu-Lan; LIU,Jian-Li

    2004-01-01

    @@ Erythrocentaurin is a relatively simple nature product isolated from the root of Gentiana macrophylla Pall.[1] The co-existed of gentiopicroside from the same species led to speculation that erythrocentaurin is a biosynthesis product of gentiopicroside. The transformation of secologanin to carbocyclic aglycone under biomimetic condition has already known (Scheme 1).[2,3] The postulated biosynthesis pathway of erythrocentaurin may be in the same way. In the process the cyclic hemiacetal of the aglycone opened to the dialdehyde which then undergoes a vinylogous aldol reaction, and then dehydroxylation and double bond migration to the title compound (Scheme 2).

  11. Nucleoside antibiotics: biosynthesis, regulation, and biotechnology.

    Science.gov (United States)

    Niu, Guoqing; Tan, Huarong

    2015-02-01

    The alarming rise in antibiotic-resistant pathogens has coincided with a decline in the supply of new antibiotics. It is therefore of great importance to find and create new antibiotics. Nucleoside antibiotics are a large family of natural products with diverse biological functions. Their biosynthesis is a complex process through multistep enzymatic reactions and is subject to hierarchical regulation. Genetic and biochemical studies of the biosynthetic machinery have provided the basis for pathway engineering and combinatorial biosynthesis to create new or hybrid nucleoside antibiotics. Dissection of regulatory mechanisms is leading to strategies to increase the titer of bioactive nucleoside antibiotics.

  12. Biosynthesis and biodegradation of wood components

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, T. (ed.)

    1985-01-01

    A textbook containing 22 chapters by various authors covers the structure of wood, the localization of polysaccharides and lignins in wood cell walls, metabolism and synthetic function of cambial tissue, cell organelles and their function in the biosynthesis of cell wall components, biosynthesis of plant cell wall polysaccharides, lignin, cutin, suberin and associated waxes, phenolic acids and monolignols, quinones, flavonoids, tannins, stilbenes and terpenoid wood extractives, the occurrence of extractives, the metabolism of phenolic acids, wood degradation by micro-organisms and fungi, and biodegradation of cellulose, hemicelluloses, lignin, and aromatic extractives of wood. An index is included.

  13. Bile acid biosynthesis and its regulation

    Directory of Open Access Journals (Sweden)

    Areta Hebanowska

    2010-10-01

    Full Text Available Bile acid biosynthesis is the main pathway of cholesterol catabolism. Bile acids are more soluble than cholesterol so are easier to excrete. As amphipathic molecules they participate in lipid digestion and absorption in the intestine and they help to excrete free cholesterol with bile. They are also ligands for nuclear receptors regulating the expression of genes involved in cholesterol metabolism. Interconversion of cholesterol into bile acids is an important point of its homeostasis. Seventeen enzymes are engaged in this process and many of them are cytochromes P450. Bile acid synthesis initiation may proceed with the “classical” pathway (starting with cholesterol hydroxylation at the C7α position or the “alternative” pathway (starting with cholesterol hydroxylation at the C27 position. Two additional pathways are possible, though their quantitative significance is small (initiated with cholesterol hydroxylations of C24 and C25 positions. Oxysterols produced are not only intermediates of bile acid biosynthesis but also important regulators of metabolism. Bile acid biosynthesis takes place in the liver, but some enzymes are also present in other organs, where they participate in regulation of cholesterol metabolism. Those enzymes are potential targets for new drugs against cholesterol metabolism disturbances. This article is a brief description of the bile acid biosynthesis pathway and participating enzymes.

  14. Biosynthesis of sphinganine-analog mycotoxins.

    Science.gov (United States)

    Du, L; Zhu, X; Gerber, R; Huffman, J; Lou, L; Jorgenson, J; Yu, F; Zaleta-Rivera, K; Wang, Q

    2008-06-01

    Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

  15. Combinatorial biosynthesis of medicinal plant secondary metabolites

    NARCIS (Netherlands)

    Julsing, Mattijs K.; Koulman, Albert; Woerdenbag, Herman J.; Quax, Wim J.; Kayser, Oliver

    2006-01-01

    Combinatorial biosynthesis is a new tool in the generation of novel natural products and for the production of rare and expensive natural products. The basic concept is combining metabolic pathways in different organisms on a genetic level. As a consequence heterologous organisms provide precursors

  16. Biosynthesis and toxicological effects of patulin.

    Science.gov (United States)

    Puel, Olivier; Galtier, Pierre; Oswald, Isabelle P

    2010-04-01

    Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects.

  17. Complete biosynthesis of opioids in yeast.

    Science.gov (United States)

    Galanie, Stephanie; Thodey, Kate; Trenchard, Isis J; Filsinger Interrante, Maria; Smolke, Christina D

    2015-09-04

    Opioids are the primary drugs used in Western medicine for pain management and palliative care. Farming of opium poppies remains the sole source of these essential medicines, despite diverse market demands and uncertainty in crop yields due to weather, climate change, and pests. We engineered yeast to produce the selected opioid compounds thebaine and hydrocodone starting from sugar. All work was conducted in a laboratory that is permitted and secured for work with controlled substances. We combined enzyme discovery, enzyme engineering, and pathway and strain optimization to realize full opiate biosynthesis in yeast. The resulting opioid biosynthesis strains required the expression of 21 (thebaine) and 23 (hydrocodone) enzyme activities from plants, mammals, bacteria, and yeast itself. This is a proof of principle, and major hurdles remain before optimization and scale-up could be achieved. Open discussions of options for governing this technology are also needed in order to responsibly realize alternative supplies for these medically relevant compounds.

  18. Chemical genetics to examine cellulose biosynthesis

    Directory of Open Access Journals (Sweden)

    Seth eDebolt

    2013-01-01

    Full Text Available Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBI have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A (CESA proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity.

  19. Microbial Exopolysaccharides: Biosynthesis and Potential Applications

    Directory of Open Access Journals (Sweden)

    K. V. Madhuri

    2014-09-01

    Full Text Available Many bacteria synthesize extracellular polysaccharides (EPSs with commercially significant physiological and therapeutic activities. Microbial polysaccharides have also been reported to have potential therapeutic applications. Recently, much attention has been devoted to the microbial exopolysaccharides (EPSs due to their numerous health benefits.EPSs from lactic acid bacteria are reported to possess antitumor effects, immunostimulatory activity, and the ability to lower blood cholesterol. EPSs also offer an alternative class of biothickeners that are widely used in the food and dairy industries and have been proven to provide strong emulsifying activity, which is important in many food formulations. It is also important to understand the mechanism of microbial biosynthesis of EPSs in order to enhance their production by genetic alterations. The potential applications and the mode of microbial biosynthesis of the EPSs have been presented in this article.

  20. Carotenoid Metabolism: Biosynthesis, Regulation,and Beyond

    Institute of Scientific and Technical Information of China (English)

    Shan Lu; Li Li

    2008-01-01

    Carotenoids are Indispensable to plants and play a critical role in human nutrition and health. Significant progress has been made in our understanding of carotenoid metabolism in plants. The biosynthetic pathway has been extensively studied.Nearly all the genes encoding the biosynthetic enzymes have been isolated and characterized from various organisms. In recent years, there is an increasing body of work on the signaling pathways and plastid development, which might provide global control of carotenoid biosynthesis and accumulation. Herein, we will highlight recent progress on the biosynthesis,regulation, and metabolic engineering of carotenoids in plants, as well as the future research towards elucidating the regulatory mechanisms and metabolic network that control carotenoid metabolism.

  1. Functional specialization in proline biosynthesis of melanoma.

    Directory of Open Access Journals (Sweden)

    Jessica De Ingeniis

    Full Text Available Proline metabolism is linked to hyperprolinemia, schizophrenia, cutis laxa, and cancer. In the latter case, tumor cells tend to rely on proline biosynthesis rather than salvage. Proline is synthesized from either glutamate or ornithine; both are converted to pyrroline-5-carboxylate (P5C, and then to proline via pyrroline-5-carboxylate reductases (PYCRs. Here, the role of three isozymic versions of PYCR was addressed in human melanoma cells by tracking the fate of (13C-labeled precursors. Based on these studies we conclude that PYCR1 and PYCR2, which are localized in the mitochondria, are primarily involved in conversion of glutamate to proline. PYCRL, localized in the cytosol, is exclusively linked to the conversion of ornithine to proline. This analysis provides the first clarification of the role of PYCRs to proline biosynthesis.

  2. Functional Specialization in Proline Biosynthesis of Melanoma

    Science.gov (United States)

    Richardson, Adam D.; Scott, David A.; Aza-Blanc, Pedro; De, Surya K.; Kazanov, Marat; Pellecchia, Maurizio; Ronai, Ze'ev; Osterman, Andrei L.; Smith, Jeffrey W.

    2012-01-01

    Proline metabolism is linked to hyperprolinemia, schizophrenia, cutis laxa, and cancer. In the latter case, tumor cells tend to rely on proline biosynthesis rather than salvage. Proline is synthesized from either glutamate or ornithine; both are converted to pyrroline-5-carboxylate (P5C), and then to proline via pyrroline-5-carboxylate reductases (PYCRs). Here, the role of three isozymic versions of PYCR was addressed in human melanoma cells by tracking the fate of 13C-labeled precursors. Based on these studies we conclude that PYCR1 and PYCR2, which are localized in the mitochondria, are primarily involved in conversion of glutamate to proline. PYCRL, localized in the cytosol, is exclusively linked to the conversion of ornithine to proline. This analysis provides the first clarification of the role of PYCRs to proline biosynthesis. PMID:23024808

  3. Circular bacteriocins: biosynthesis and mode of action.

    Science.gov (United States)

    Gabrielsen, Christina; Brede, Dag A; Nes, Ingolf F; Diep, Dzung B

    2014-11-01

    Circular bacteriocins are a group of N-to-C-terminally linked antimicrobial peptides, produced by Gram-positive bacteria of the phylum Firmicutes. Circular bacteriocins generally exhibit broad-spectrum antimicrobial activity, including against common food-borne pathogens, such as Clostridium and Listeria spp. These peptides are further known for their high pH and thermal stability, as well as for resistance to many proteolytic enzymes, properties which make this group of bacteriocins highly promising for potential industrial applications and their biosynthesis of particular interest as a possible model system for the synthesis of highly stable bioactive peptides. In this review, we summarize the current knowledge on this group of bacteriocins, with emphasis on the recent progress in understanding circular bacteriocin genetics, biosynthesis, and mode of action; in addition, we highlight the current challenges and future perspectives for the application of these peptides.

  4. Natural rubber biosynthesis in plants: rubber transferase.

    Science.gov (United States)

    Cornish, Katrina; Xie, Wenshuang

    2012-01-01

    Rubber biosynthesis in plants is a fascinating biochemical system, which evolved at the dawn of the dicotyledoneae and is present in at least four of the dictolydonous superorders. Rubber biosynthesis is catalyzed by a membrane complex in a monolayer membrane envelope, requires two distinct substrates and a divalent cation cofactor, and produces a high-molecular-weight isoprenoid polymer. A solid understanding of this system underpins valuable papers in the literature. However, the published literature is rife with unreliable reports in which the investigators have fallen into traps created by the current incomplete understanding of the biochemistry of rubber synthesis. In this chapter, we attempt to guide both new and more established researchers around these pitfalls.

  5. Plant Terpenoids: Biosynthesis and Ecological Functions

    Institute of Scientific and Technical Information of China (English)

    Ai-Xia Cheng; Yong-Gen Lou; Ying-Bo Mao; Shan Lu; Ling-Jian Wang; Xiao-Ya Chen

    2007-01-01

    Among plant secondary metabolites terpenoids are a structurally most diverse group; they function as phytoalexins in plant direct defense, or as signals in indirect defense responses which involves herbivores and their natural enemies. In recent years, more and more attention has been paid to the investigation of the ecological role of plant terpenoids. The biosynthesis pathways of monoterpenes, sesquiterpenes, and diterpenes include the synthesis of C5 precursor isopentenyl diphosphate (IPP) and its allylic isomer dimethylallyl diphosphate (DMAPP), the synthesis of the immediate diphosphate precursors, and the formation of the diverse terpenoids. Terpene synthases (TPSs) play a key role in volatile terpene synthesis. By expression of the TPS genes, significant achievements have been made on metabolic engineering to increase terpenoid production. This review mainly summarizes the recent research progress in elucidating the ecological role of terpenoids and characterization of the enzymes involved in the terpenoid biosynthesis. Spatial and temporal regulations of terpenoids metabolism are also discussed.

  6. Enzymology of the carnitine biosynthesis pathway.

    Science.gov (United States)

    Strijbis, Karin; Vaz, Frédéric M; Distel, Ben

    2010-05-01

    The water-soluble zwitterion carnitine is an essential metabolite in eukaryotes required for fatty acid oxidation as it functions as a carrier during transfer of activated acyl and acetyl groups across intracellular membranes. Most eukaryotes are able to synthesize carnitine endogenously, besides their capacity to take up carnitine from the diet or extracellular medium through plasma membrane transporters. This review discusses the current knowledge on carnitine homeostasis with special emphasis on the enzymology of the four steps of the carnitine biosynthesis pathway.

  7. Biosynthesis of the Caenorhabditis elegans dauer pheromone

    OpenAIRE

    Butcher, Rebecca A.; Ragains, Justin R.; Li, Weiqing; RUVKUN, GARY; Clardy, Jon; Mak, Ho Yi

    2009-01-01

    To sense its population density and to trigger entry into the stress-resistant dauer larval stage, Caenorhabditis elegans uses the dauer pheromone, which consists of ascaroside derivatives with short, fatty acid-like side chains. Although the dauer pheromone has been studied for 25 years, its biosynthesis is completely uncharacterized. The daf-22 mutant is the only known mutant defective in dauer pheromone production. Here, we show that daf-22 encodes a homolog of human sterol carrier protein...

  8. Microbial biosynthesis of nontoxic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Swarup, E-mail: swaruproy@klyuniv.ac.in [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Das, Tapan Kumar [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Maiti, Guru Prasad [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India); Department of Anesthesiology, Texas Tech University Health science Center, 3601 4th Street, Lubbock, TX 79430 (United States); Basu, Utpal [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India)

    2016-01-15

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  9. Lipopolysaccharide Structure and Biosynthesis in Helicobacter pylori.

    Science.gov (United States)

    Li, Hong; Liao, Tingting; Debowski, Aleksandra W; Tang, Hong; Nilsson, Hans-Olof; Stubbs, Keith A; Marshall, Barry J; Benghezal, Mohammed

    2016-12-01

    This review covers the current knowledge and gaps in Helicobacter pylori lipopolysaccharide (LPS) structure and biosynthesis. H. pylori is a Gram-negative bacterium which colonizes the luminal surface of the human gastric epithelium. Both a constitutive alteration of the lipid A preventing TLR4 elicitation and host mimicry of the Lewis antigen decorated O-antigen of H. pylori LPS promote immune escape and chronic infection. To date, the complete structure of H. pylori LPS is not available, and the proposed model is a linear arrangement composed of the inner core defined as the hexa-saccharide (Kdo-LD-Hep-LD-Hep-DD-Hep-Gal-Glc), the outer core composed of a conserved trisaccharide (-GlcNAc-Fuc-DD-Hep-) linked to the third heptose of the inner core, the glucan, the heptan and a variable O-antigen, generally consisting of a poly-LacNAc decorated with Lewis antigens. Although the glycosyltransferases (GTs) responsible for the biosynthesis of the H. pylori O-antigen chains have been identified and characterized, there are many gaps in regard to the biosynthesis of the core LPS. These limitations warrant additional mutagenesis and structural studies to obtain the complete LPS structure and corresponding biosynthetic pathway of this important gastric bacterium.

  10. Transcellular biosynthesis of eicosanoid lipid mediators.

    Science.gov (United States)

    Capra, Valérie; Rovati, G Enrico; Mangano, Paolo; Buccellati, Carola; Murphy, Robert C; Sala, Angelo

    2015-04-01

    The synthesis of oxygenated eicosanoids is the result of the coordinated action of several enzymatic activities, from phospholipase A2 that releases the polyunsaturated fatty acids from membrane phospholipids, to primary oxidative enzymes, such as cyclooxygenases and lipoxygenases, to isomerases, synthases and hydrolases that carry out the final synthesis of the biologically active metabolites. Cells possessing the entire enzymatic machinery have been studied as sources of bioactive eicosanoids, but early on evidence proved that biosynthetic intermediates, albeit unstable, could move from one cell type to another. The biosynthesis of bioactive compounds could therefore be the result of a coordinated effort by multiple cell types that has been named transcellular biosynthesis of the eicosanoids. In several cases cells not capable of carrying out the complete biosynthetic process, due to the lack of key enzymes, have been shown to efficiently contribute to the final production of prostaglandins, leukotrienes and lipoxins. We will review in vitro studies, complex functional models, and in vivo evidences of the transcellular biosynthesis of eicosanoids and the biological relevance of the metabolites resulting from this unique biosynthetic pathway. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

  11. [Regulation of antibiotic biosynthesis in Streptomycetes].

    Science.gov (United States)

    Matseliukh, B P

    2006-01-01

    The review of literature presents the modern data about cascade regulation of antibiotic biosynthesis in Streptomycetes including basal and global levels. The first regulatory level is presented by related proteins of SARP family playing the role of positive transcription factors of pathway-specific genes of clusters of antibiotic biosynthesis. In their turn these regulatory genes are under the control of higher regulatory level represented by bldA- and A-factor-dependent cascade regulation and two-component signal transduction system (AfsK-AfsR, AbsAl-AbsA2, AfsQ1-AfsQ2 and others), consisting of sensor protein kinase and response regulator protein.Streptomycetes, in contrast to other microorganisms, have dozens of protein kinases and related regulator proteins that testifies to the great importance of protein phosphorylation in regulation of secondary metabolism and morphogenesis in cell response to internal and external signals. The role of camp, ppGpp and other proteins in regulation of antibiotic biosynthesis was also considered in this review.

  12. Acetamido sugar biosynthesis in the Euryarchaea.

    Science.gov (United States)

    Namboori, Seema C; Graham, David E

    2008-04-01

    Archaea and eukaryotes share a dolichol phosphate-dependent system for protein N-glycosylation. In both domains, the acetamido sugar N-acetylglucosamine (GlcNAc) forms part of the core oligosaccharide. However, the archaeal Methanococcales produce GlcNAc using the bacterial biosynthetic pathway. Key enzymes in this pathway belong to large families of proteins with diverse functions; therefore, the archaeal enzymes could not be identified solely using comparative sequence analysis. Genes encoding acetamido sugar-biosynthetic proteins were identified in Methanococcus maripaludis using phylogenetic and gene cluster analyses. Proteins expressed in Escherichia coli were purified and assayed for the predicted activities. The MMP1680 protein encodes a universally conserved glucosamine-6-phosphate synthase. The MMP1077 phosphomutase converted alpha-D-glucosamine-6-phosphate to alpha-D-glucosamine-1-phosphate, although this protein is more closely related to archaeal pentose and glucose phosphomutases than to bacterial glucosamine phosphomutases. The thermostable MJ1101 protein catalyzed both the acetylation of glucosamine-1-phosphate and the uridylyltransferase reaction with UTP to produce UDP-GlcNAc. The MMP0705 protein catalyzed the C-2 epimerization of UDP-GlcNAc, and the MMP0706 protein used NAD(+) to oxidize UDP-N-acetylmannosamine, forming UDP-N-acetylmannosaminuronate (ManNAcA). These two proteins are similar to enzymes used for proteobacterial lipopolysaccharide biosynthesis and gram-positive bacterial capsule production, suggesting a common evolutionary origin and a widespread distribution of ManNAcA. UDP-GlcNAc and UDP-ManNAcA biosynthesis evolved early in the euryarchaeal lineage, because most of their genomes contain orthologs of the five genes characterized here. These UDP-acetamido sugars are predicted to be precursors for flagellin and S-layer protein modifications and for the biosynthesis of methanogenic coenzyme B.

  13. Biosynthesis of Nitrogenase FeMoco

    OpenAIRE

    Hu, Yilin; Ribbe, Markus W.

    2011-01-01

    Biosynthesis of nitrogenase FeMoco is a highly complex process that requires, minimally, the participation of nifS, nifU, nifB, nifE, nifN, nifV, nifH, nifD and nifK gene products. Previous genetic analyses have identified the essential factors for the assembly of FeMoco; however, the exact functions of these factors and the precise sequence of events during the assembly process had remained unclear until recently, when a number of the biosynthetic intermediates of FeMoco were identified and ...

  14. Marine Pyridoacridine Alkaloids: Biosynthesis and Biological Activities.

    Science.gov (United States)

    Ibrahim, Sabrin R M; Mohamed, Gamal A

    2016-01-01

    Pyridoacridines are a class of strictly marine-derived alkaloids that constitute one of the largest chemical families of marine alkaloids. During the last few years, both natural pyridoacridines and their analogues have constituted excellent targets for synthetic works. They have been the subject of intense study due to their significant biological activities; cytotoxic, antibacterial, antifungal, antiviral, insecticidal, anti-HIV, and anti-parasitic activities. In the present review, 95 pyridoacridine alkaloids isolated from marine organisms are discussed in term of their occurrence, biosynthesis, biological activities, and structural assignment.

  15. Green biosynthesis of floxuridine by immobilized microorganisms.

    Science.gov (United States)

    Rivero, Cintia W; Britos, Claudia N; Lozano, Mario E; Sinisterra, Jose V; Trelles, Jorge A

    2012-06-01

    This work describes an efficient, simple, and green bioprocess for obtaining 5-halogenated pyrimidine nucleosides from thymidine by transglycosylation using whole cells. Biosynthesis of 5-fluoro-2'-deoxyuridine (floxuridine) was achieved by free and immobilized Aeromonas salmonicida ATCC 27013 with an 80% and 65% conversion occurring in 1 h, respectively. The immobilized biocatalyst was stable for more than 4 months in storage conditions (4 °C) and could be reused at least 30 times without loss of its activity. This microorganism was able to biosynthesize 2.0 mg L(-1) min(-1) (60%) of 5-chloro-2'-deoxyuridine in 3 h. These halogenated pyrimidine 2'-deoxynucleosides are used as antitumoral agents.

  16. Biosynthesis of 2-methylisoborneol in cyanobacteria.

    Science.gov (United States)

    Giglio, S; Chou, W K W; Ikeda, H; Cane, D E; Monis, P T

    2011-02-01

    The production of odiferous metabolites, such as 2-methlyisoborneol (MIB), is a major concern for water utilities worldwide. Although MIB has no known biological function, the presence of the earthy/musty taste and odor attributed to this compound result in the reporting of numerous complaints by consumers, which undermines water utility performance and the safe and adequate provision of potable waters. Cyanobacteria are the major producers of MIB in natural waters, by mechanisms that have heretofore remained largely unstudied. To investigate the fundamental biological mechanism of MIB biosynthesis in cyanobacteria, the genome of a MIB-producing Pseudanabaena limnetica was sequenced using Next Generation Sequencing, and the recombinant proteins derived from the putative MIB biosynthetic genes were biochemically characterized. We demonstrate that the biosynthesis of MIB in cyanobacteria is a result of 2 key reactions: 1) a S-adenosylmethionine-dependent methylation of the monoterpene precursor geranyl diphosphate (GPP) to 2-methyl-GPP catalyzed by geranyl diphosphate 2-methyltransferase (GPPMT) and 2) further cyclization of 2-methyl-GPP to MIB catalyzed by MIB synthase (MIBS) as part of a MIB operon. Based on a comparison of the component MIB biosynthetic genes in actinomycetes and cyanobacterial organisms, we hypothesize that there have been multiple rearrangements of the genes in this operon.

  17. BIOSYNTHESIS AND PROPERTIES OF ANTIBIOTIC BATUMIN

    Directory of Open Access Journals (Sweden)

    V. V. Klochko

    2014-12-01

    Full Text Available Biosynthesis of antistaphylococcal antibiotic batumin under periodic conditions of Pseudomonas batumici growth has been studied. Antibiotic synthesis in fermenter occurred across the culture growth and achieved its maximal value after 50–55 hours. The active oxygen utilization by the producing strain was observed during 20–55 hours of fermentation with maximum after 40–45 hours. Antibiotic yield was 175–180 mg/l and depended on intensity of aeration. contrast to «freshly isolated» antibiotic after fermentation the long-term kept batumin has shown two identical by molecular mass peaks according to the chromato-mass spectrometric analysis. Taking into account of batumin molecule structure the conclusion has been made that the most probable isomerization type is keto-enolic tautomerism. At the same time batumin is diastereoisomer of kalimantacin A which has the same chemical structure. The optic rotation angle is [α]d25 = +56.3° for kalimantacin and [α]d25 = –13.5° for batumin. The simultaneous P. batumici growth and antibiotic biosynthesis and the ability of this molecule to optical isomerisation and keto-enolic forms formation allow us to suppose that batumin plays a certain role in metabolism of the producing strain.

  18. Plant Sterols: Diversity, Biosynthesis, and Physiological Functions.

    Science.gov (United States)

    Valitova, J N; Sulkarnayeva, A G; Minibayeva, F V

    2016-08-01

    Sterols, which are isoprenoid derivatives, are structural components of biological membranes. Special attention is now being given not only to their structure and function, but also to their regulatory roles in plants. Plant sterols have diverse composition; they exist as free sterols, sterol esters with higher fatty acids, sterol glycosides, and acylsterol glycosides, which are absent in animal cells. This diversity of types of phytosterols determines a wide spectrum of functions they play in plant life. Sterols are precursors of a group of plant hormones, the brassinosteroids, which regulate plant growth and development. Furthermore, sterols participate in transmembrane signal transduction by forming lipid microdomains. The predominant sterols in plants are β-sitosterol, campesterol, and stigmasterol. These sterols differ in the presence of a methyl or an ethyl group in the side chain at the 24th carbon atom and are named methylsterols or ethylsterols, respectively. The balance between 24-methylsterols and 24-ethylsterols is specific for individual plant species. The present review focuses on the key stages of plant sterol biosynthesis that determine the ratios between the different types of sterols, and the crosstalk between the sterol and sphingolipid pathways. The main enzymes involved in plant sterol biosynthesis are 3-hydroxy-3-methylglutaryl-CoA reductase, C24-sterol methyltransferase, and C22-sterol desaturase. These enzymes are responsible for maintaining the optimal balance between sterols. Regulation of the ratios between the different types of sterols and sterols/sphingolipids can be of crucial importance in the responses of plants to stresses.

  19. Molecular regulation of antibiotic biosynthesis in streptomyces.

    Science.gov (United States)

    Liu, Gang; Chater, Keith F; Chandra, Govind; Niu, Guoqing; Tan, Huarong

    2013-03-01

    Streptomycetes are the most abundant source of antibiotics. Typically, each species produces several antibiotics, with the profile being species specific. Streptomyces coelicolor, the model species, produces at least five different antibiotics. We review the regulation of antibiotic biosynthesis in S. coelicolor and other, nonmodel streptomycetes in the light of recent studies. The biosynthesis of each antibiotic is specified by a large gene cluster, usually including regulatory genes (cluster-situated regulators [CSRs]). These are the main point of connection with a plethora of generally conserved regulatory systems that monitor the organism's physiology, developmental state, population density, and environment to determine the onset and level of production of each antibiotic. Some CSRs may also be sensitive to the levels of different kinds of ligands, including products of the pathway itself, products of other antibiotic pathways in the same organism, and specialized regulatory small molecules such as gamma-butyrolactones. These interactions can result in self-reinforcing feed-forward circuitry and complex cross talk between pathways. The physiological signals and regulatory mechanisms may be of practical importance for the activation of the many cryptic secondary metabolic gene cluster pathways revealed by recent sequencing of numerous Streptomyces genomes.

  20. Essences in Metabolic Engineering of Lignan Biosynthesis

    Directory of Open Access Journals (Sweden)

    Honoo Satake

    2015-05-01

    Full Text Available Lignans are structurally and functionally diverse phytochemicals biosynthesized in diverse plant species and have received wide attentions as leading compounds of novel drugs for tumor treatment and healthy diets to reduce of the risks of lifestyle-related non-communicable diseases. However, the lineage-specific distribution and the low-amount of production in natural plants, some of which are endangered species, hinder the efficient and stable production of beneficial lignans. Accordingly, the development of new procedures for lignan production is of keen interest. Recent marked advances in the molecular and functional characterization of lignan biosynthetic enzymes and endogenous and exogenous factors for lignan biosynthesis have suggested new methods for the metabolic engineering of lignan biosynthesis cascades leading to the efficient, sustainable, and stable lignan production in plants, including plant cell/organ cultures. Optimization of light conditions, utilization of a wide range of elicitor treatments, and construction of transiently gene-transfected or transgenic lignan-biosynthesizing plants are mainly being attempted. This review will present the basic and latest knowledge regarding metabolic engineering of lignans based on their biosynthetic pathways and biological activities, and the perspectives in lignan production via metabolic engineering.

  1. Unique biosynthesis of sesquarterpenes (C35 terpenes).

    Science.gov (United States)

    Sato, Tsutomu

    2013-01-01

    To the best of my knowledge, only 19 cyclic and 8 linear C35 terpenes have been identified to date, and no family name was assigned to this terpene class until recently. In 2011, it was proposed that these C35 terpenes should be called sesquarterpenes. This review highlights the biosynthesis of two kinds of sesquarterpenes (C35 terpenes) that are produced via cyclization of a linear C35 isoprenoid in Bacillus and Mycobacterium species. In Bacillus species, a new type of terpene cyclase that has no sequence homology with any known terpene synthases, as well as a bifunctional terpene cyclase that biosynthesizes two classes of cyclic terpenes with different numbers of carbons as natural products, have been identified. On the other hand, in Mycobacterium species, the first bifunctional Z-prenyltransferase has been found, but a novel terpene cyclase and a unique polyprenyl reductase remain unidentified. The identification of novel enzyme types should lead to the discovery of many homologous enzymes and their products including novel natural compounds. On the other hand, many enzymes responsible for the biosynthesis of natural products have low substrate specificities in vitro. Therefore, to find novel natural products present in organisms, the multifunctionality of enzymes in the biosynthetic pathway of natural products should be analyzed.

  2. BIOSYNTHESIS AND ACTION OF JASMONATES IN PLANTS.

    Science.gov (United States)

    Creelman, Robert A.; Mullet, John E.

    1997-06-01

    Jasmonic acid and its derivatives can modulate aspects of fruit ripening, production of viable pollen, root growth, tendril coiling, and plant resistance to insects and pathogens. Jasmonate activates genes involved in pathogen and insect resistance, and genes encoding vegetative storage proteins, but represses genes encoding proteins involved in photosynthesis. Jasmonic acid is derived from linolenic acid, and most of the enzymes in the biosynthetic pathway have been extensively characterized. Modulation of lipoxygenase and allene oxide synthase gene expression in transgenic plants raises new questions about the compartmentation of the biosynthetic pathway and its regulation. The activation of jasmonic acid biosynthesis by cell wall elicitors, the peptide systemin, and other compounds will be related to the function of jasmonates in plants. Jasmonate modulates gene expression at the level of translation, RNA processing, and transcription. Promoter elements that mediate responses to jasmonate have been isolated. This review covers recent advances in our understanding of how jasmonate biosynthesis is regulated and relates this information to knowledge of jasmonate modulated gene expression.

  3. Biosynthesis of the Caenorhabditis elegans dauer pheromone.

    Science.gov (United States)

    Butcher, Rebecca A; Ragains, Justin R; Li, Weiqing; Ruvkun, Gary; Clardy, Jon; Mak, Ho Yi

    2009-02-10

    To sense its population density and to trigger entry into the stress-resistant dauer larval stage, Caenorhabditis elegans uses the dauer pheromone, which consists of ascaroside derivatives with short, fatty acid-like side chains. Although the dauer pheromone has been studied for 25 years, its biosynthesis is completely uncharacterized. The daf-22 mutant is the only known mutant defective in dauer pheromone production. Here, we show that daf-22 encodes a homolog of human sterol carrier protein SCPx, which catalyzes the final step in peroxisomal fatty acid beta-oxidation. We also show that dhs-28, which encodes a homolog of the human d-bifunctional protein that acts just upstream of SCPx, is also required for pheromone production. Long-term daf-22 and dhs-28 cultures develop dauer-inducing activity by accumulating less active, long-chain fatty acid ascaroside derivatives. Thus, daf-22 and dhs-28 are required for the biosynthesis of the short-chain fatty acid-derived side chains of the dauer pheromone and link dauer pheromone production to metabolic state.

  4. Phytochrome-mediated Carotenoids Biosynthesis in Ripening Tomatoes.

    Science.gov (United States)

    Thomas, R L; Jen, J J

    1975-09-01

    Red light induced and far red light inhibited carotenoid biosynthesis in ripening tomatoes (Lycopersicon esculentum Mill.) when compared to controls kept in the dark. Red illumination following far red illumination reversed the inhibitory action of far red light on carotenoid biosynthesis, suggesting a phytochrome-mediated process. Quantitation of individual carotenoids favored the hypothesis of two separate carotenoid biosynthetic pathways in tomatoes.

  5. Biosynthesis of Silver Nanoparticles Using Marine Sponge

    Directory of Open Access Journals (Sweden)

    Mahta Rezazaeh Hamed

    2015-12-01

    Full Text Available Biosynthesis of silver nanoparticles using marine sponge extract Haliclona was carried out. Marine sponges' extracts are responsible for the reduction of silver nitrate solution. Silver nanoparticles synthesized using fresh and dry marine sponge. Experimental factors including, time duration, pH, temperature were optimized. Silver nanoparticles were characterized by UV-Visible spectrophotometry. The sizes of synthesis silver nanoparticles were 27-46 nm and confirmed by scanning electron microscopy (SEM. X-ray diffraction (XRD crystallography indicated the silver nanoparticles crystalline nature. Fourier transform infrared spectroscopy (FT-IR was revealed the functional groups of extract of Haliclona, which are capable of reduction of silver nanoparticles. This method is a cost-effective, eco-friendly and nontoxic procedure..

  6. Biosynthesis of Nitrogenase FeMoco.

    Science.gov (United States)

    Hu, Yilin; Ribbe, Markus W

    2011-05-01

    Biosynthesis of nitrogenase FeMoco is a highly complex process that requires, minimally, the participation of nifS, nifU, nifB, nifE, nifN, nifV, nifH, nifD and nifK gene products. Previous genetic analyses have identified the essential factors for the assembly of FeMoco; however, the exact functions of these factors and the precise sequence of events during the assembly process had remained unclear until recently, when a number of the biosynthetic intermediates of FeMoco were identified and characterized by combined biochemical, spectroscopic and structural analyses. This review gives a brief account of the recent progress toward understanding the assembly process of FeMoco, which has identified some important missing pieces of this biosynthetic puzzle.

  7. Biosynthesis and function of plant lipids

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, W.W.; Mudd, J.B.; Gibbs, M. (eds.)

    1983-01-01

    The Sixth Annual Symposium in Botany and Plant Physiology was held January 13-15, 1983, at the University of California, Riverside. This volume comprises the papers that were presented. Subjects discussed at the symposium covered a wide range in the field of plant lipids. Biosynthesis of lipids occupied an important fraction of the presentations at the symposium. Subjects included detailed studies of the enzymes of fatty acid synthesis, several discussions of the incorporation of fatty acids into glycerolipids and the further modification of the fatty acids, and the synthesis of glycerolipids and desaturation of fatty acids in both maturing oilseeds and chloroplasts. The physicochemical studies of glycerolipids and sterols in artificial membranes have led to distinct conclusions about their behaviour which must be relevant in the biological membrane. Results on the functional consequences of modifying the galactolipid composition in the chloroplast were an encouraging sign of progress in the attempts to relate membrane lipid composition to physiological function.

  8. Biosurfactant Mediated Biosynthesis of Selected Metallic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Grażyna A. Płaza

    2014-08-01

    Full Text Available Developing a reliable experimental protocol for the synthesis of nanomaterials is one of the challenging topics in current nanotechnology particularly in the context of the recent drive to promote green technologies in their synthesis. The increasing need to develop clean, nontoxic and environmentally safe production processes for nanoparticles to reduce environmental impact, minimize waste and increase energy efficiency has become essential in this field. Consequently, recent studies on the use of microorganisms in the synthesis of selected nanoparticles are gaining increased interest as they represent an exciting area of research with considerable development potential. Microorganisms are known to be capable of synthesizing inorganic molecules that are deposited either intra- or extracellularly. This review presents a brief overview of current research on the use of biosurfactants in the biosynthesis of selected metallic nanoparticles and their potential importance.

  9. Reinvigorating natural product combinatorial biosynthesis with synthetic biology.

    Science.gov (United States)

    Kim, Eunji; Moore, Bradley S; Yoon, Yeo Joon

    2015-09-01

    Natural products continue to play a pivotal role in drug-discovery efforts and in the understanding if human health. The ability to extend nature's chemistry through combinatorial biosynthesis--altering functional groups, regiochemistry and scaffold backbones through the manipulation of biosynthetic enzymes--offers unique opportunities to create natural product analogs. Incorporating emerging synthetic biology techniques has the potential to further accelerate the refinement of combinatorial biosynthesis as a robust platform for the diversification of natural chemical drug leads. Two decades after the field originated, we discuss the current limitations, the realities and the state of the art of combinatorial biosynthesis, including the engineering of substrate specificity of biosynthetic enzymes and the development of heterologous expression systems for biosynthetic pathways. We also propose a new perspective for the combinatorial biosynthesis of natural products that could reinvigorate drug discovery by using synthetic biology in combination with synthetic chemistry.

  10. Structure, Biosynthesis, and Occurrence of Bacterial Pyrrolizidine Alkaloids

    DEFF Research Database (Denmark)

    Schimming, Olivia; Challinor, Victoria L; Tobias, Nicholas J;

    2015-01-01

    Pyrrolizidine alkaloids (PAs) are widespread plant natural products with potent toxicity and bioactivity. Herein, the identification of bacterial PAs from entomopathogenic bacteria using differential analysis by 2D NMR spectroscopy (DANS) and mass spectrometry is described. Their biosynthesis...

  11. Biosynthesis and molecular genetics of polyketides in marine dinoflagellates.

    Science.gov (United States)

    Kellmann, Ralf; Stüken, Anke; Orr, Russell J S; Svendsen, Helene M; Jakobsen, Kjetill S

    2010-03-31

    Marine dinoflagellates are the single most important group of algae that produce toxins, which have a global impact on human activities. The toxins are chemically diverse, and include macrolides, cyclic polyethers, spirolides and purine alkaloids. Whereas there is a multitude of studies describing the pharmacology of these toxins, there is limited or no knowledge regarding the biochemistry and molecular genetics involved in their biosynthesis. Recently, however, exciting advances have been made. Expressed sequence tag sequencing studies have revealed important insights into the transcriptomes of dinoflagellates, whereas other studies have implicated polyketide synthase genes in the biosynthesis of cyclic polyether toxins, and the molecular genetic basis for the biosynthesis of paralytic shellfish toxins has been elucidated in cyanobacteria. This review summarises the recent progress that has been made regarding the unusual genomes of dinoflagellates, the biosynthesis and molecular genetics of dinoflagellate toxins. In addition, the evolution of these metabolic pathways will be discussed, and an outlook for future research and possible applications is provided.

  12. New players in the regulation of ecdysone biosynthesis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdysone biosynthesis is regulated is crucial to fully understand these sophisticated developmental switches. Here we summarized recent findings in the regulation of ecdysone biosynthesis from the aspects of cell signaling, key biosynthetic enzymes and substrate cholesterol trafficking.

  13. Initiation of the flexirubin biosynthesis in Chitinophaga pinensis

    OpenAIRE

    Schöner, Tim A.; Fuchs, Sebastian W.; Schönau, Christian; Helge B Bode

    2014-01-01

    Bacteria from the Bacteroidetes phylum are known producers of the chemotaxonomic relevant flexirubins. These orange pigments comprise a non-isoprenoid aryl-polyene carboxylic acid esterified with a dialkylresorcinol. Herein, we report a gene cluster from C hitinophaga pinensis encoding the biosynthesis of the polyene moiety and the biochemical characterization of a tyrosine ammonia-lyase and a 4-coumarate-CoA ligase responsible for the initiation of the polyene biosynthesis. Additionally, the...

  14. Engineered biosynthesis of bacterial aromatic polyketides in Escherichia coli

    OpenAIRE

    Zhang, Wenjun; Li, Yanran; Tang, Yi

    2008-01-01

    Bacterial aromatic polyketides are important therapeutic compounds including front line antibiotics and anticancer drugs. It is one of the last remaining major classes of natural products of which the biosynthesis has not been reconstituted in the genetically superior host Escherichia coli. Here, we demonstrate the engineered biosynthesis of bacterial aromatic polyketides in E. coli by using a dissected and reassembled fungal polyketide synthase (PKS). The minimal PKS of the megasynthase PKS4...

  15. Structure, Biosynthesis, and Occurrence of Bacterial Pyrrolizidine Alkaloids.

    Science.gov (United States)

    Schimming, Olivia; Challinor, Victoria L; Tobias, Nicholas J; Adihou, Hélène; Grün, Peter; Pöschel, Laura; Richter, Christian; Schwalbe, Harald; Bode, Helge B

    2015-10-19

    Pyrrolizidine alkaloids (PAs) are widespread plant natural products with potent toxicity and bioactivity. Herein, the identification of bacterial PAs from entomopathogenic bacteria using differential analysis by 2D NMR spectroscopy (DANS) and mass spectrometry is described. Their biosynthesis was elucidated to involve a non-ribosomal peptide synthetase. The occurrence of these biosynthesis gene clusters in Gram-negative and Gram-positive bacteria indicates an important biological function in bacteria.

  16. Histidine biosynthesis, its regulation and biotechnological application in Corynebacterium glutamicum

    OpenAIRE

    Kulis-Horn, Robert K; Persicke, Marcus; Kalinowski, Jörn

    2013-01-01

    l-Histidine biosynthesis is an ancient metabolic pathway present in bacteria, archaea, lower eukaryotes, and plants. For decades l-histidine biosynthesis has been studied mainly in Escherichia coli and Salmonella typhimurium, revealing fundamental regulatory processes in bacteria. Furthermore, in the last 15 years this pathway has been also investigated intensively in the industrial amino acid-producing bacterium Corynebacterium glutamicum, revealing similarities to E. coli and S. typhimurium...

  17. Control of triacylglycerol biosynthesis in plants

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-31

    Seeds of most species of the Umbelliferae (Apiaciae), Araliaceae, and Garryaceae families are characterized by their high content of the unusual C[sub 18] monounsaturated fatty acid petroselinic acid (18:l[Delta][sup 6cis]). Prior to a recent report of this lab, little was known of the biosynthetic origin of the cis[Delta][sup 6] double bond of petroselinic acid. Such knowledge may be of both biochemical and biotechnological significance. Because petroselinic acid is potentially the product of a novel desaturase, information regarding its synthesis may contribute to an understanding of fatty acid desaturation mechanisms in plants. Through chemical cleavage at its double bond, petroselinic acid can be used as a precursor of lauric acid (12:0), a component of detergents and surfactants, and adipic acid (6:0 dicarboxylic), the monomeric component of nylon 6,6. Therefore, the development of an agronomic source of an oil rich in petroselinic acid is of biotechnological interest. As such, studies of petroselinic acid biosynthesis may provide basic information required for any attempt to genetically engineer the production and accumulation of this fatty acid in an existing oilseed.

  18. Plant Cell Wall Matrix Polysaccharide Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Ajay Pal S. Sandhu; Gursharn S. Randhawa; Kanwarpal S. Dhugga

    2009-01-01

    The wall of an expanding plant cell consists primarily of cellulose microfibrils embedded in a matrix of hemi-cellulosic and pectic polysaccharides along with small amounts of structural and enzymatic proteins. Matrix polysacchar-ides are synthesized in the Golgi and exported to the cell wall by exocytosis, where they intercalate among cellulose microfibrUs, which are made at the plasma membrane and directly deposited into the cell wall. Involvement of Golgi glucan synthesis in auxin-induced cell expansion has long been recognized; however, only recently have the genes corresponding to glucan synthases been identified. Biochemical purification was unsuccessful because of the labile nature and very low abundance of these enzymes. Mutational genetics also proved fruitless. Expression of candidate genes identified through gene expression profiling or comparative genomics in heterologous systems followed by functional characterization has been relatively successful. Several genes from the cellulose synthase-like (Cs/) family have been found to be involved in the synthesis of various hemicellulosic glycans. The usefulness of this approach, however, is limited to those enzymes that probably do not form complexes consisting of unrelated proteins. Nonconventional approaches will continue to incre-mentally unravel the mechanisms of Golgi polysaccharide biosynthesis.

  19. The regulation and biosynthesis of antimycins

    Directory of Open Access Journals (Sweden)

    Ryan F. Seipke

    2013-11-01

    Full Text Available Antimycins (>40 members were discovered nearly 65 years ago but the discovery of the gene cluster encoding antimycin biosynthesis in 2011 has facilitated rapid progress in understanding the unusual biosynthetic pathway. Antimycin A is widely used as a piscicide in the catfish farming industry and also has potent killing activity against insects, nematodes and fungi. The mode of action of antimycins is to inhibit cytochrome c reductase in the electron transport chain and halt respiration. However, more recently, antimycin A has attracted attention as a potent and selective inhibitor of the mitochondrial anti-apoptotic proteins Bcl-2 and Bcl-xL. Remarkably, this inhibition is independent of the main mode of action of antimycins such that an artificial derivative named 2-methoxyantimycin A inhibits Bcl-xL but does not inhibit respiration. The Bcl-2/Bcl-xL family of proteins are over-produced in cancer cells that are resistant to apoptosis-inducing chemotherapy agents, so antimycins have great potential as anticancer drugs used in combination with existing chemotherapeutics. Here we review what is known about antimycins, the regulation of the ant gene cluster and the unusual biosynthetic pathway.

  20. Biosynthesis and biological action of pineal allopregnanolone

    Directory of Open Access Journals (Sweden)

    Kazuyoshi eTsutsui

    2014-05-01

    Full Text Available The pineal gland transduces photoperiodic changes to the neuroendocrine system by rhythmic secretion of melatonin. We recently provided new evidence that the pineal gland is a major neurosteroidogenic organ and actively produces a variety of neurosteroids de novo from cholesterol in birds. Notably, allopregnanolone is a major pineal neurosteroid that is far more actively produced in the pineal gland than the brain and secreted by the pineal gland in juvenile birds. Subsequently, we have demonstrated the biological action of pineal allopregnanolone on Purkinje cells in the cerebellum during development in juvenile birds. Pinealectomy (Px induces apoptosis of Purkinje cells, whereas allopregnanolone administration to Px chicks prevents cell death. Furthermore, Px increases the number of Purkinje cells that express active caspase-3, a crucial mediator of apoptosis, and allopregnanolone administration to Px chicks decreases the number of Purkinje cells expressing active caspase-3. It thus appears that pineal allopregnanolone prevents cell death of Purkinje cells by suppressing the activity of caspase-3 during development. This paper highlights new aspects of the biosynthesis and biological action of pineal allopregnanolone.

  1. A Biotin Biosynthesis Gene Restricted to Helicobacter.

    Science.gov (United States)

    Bi, Hongkai; Zhu, Lei; Jia, Jia; Cronan, John E

    2016-02-12

    In most bacteria the last step in synthesis of the pimelate moiety of biotin is cleavage of the ester bond of pimeloyl-acyl carrier protein (ACP) methyl ester. The paradigm cleavage enzyme is Escherichia coli BioH which together with the BioC methyltransferase allows synthesis of the pimelate moiety by a modified fatty acid biosynthetic pathway. Analyses of the extant bacterial genomes showed that bioH is absent from many bioC-containing bacteria and is replaced by other genes. Helicobacter pylori lacks a gene encoding a homologue of the known pimeloyl-ACP methyl ester cleavage enzymes suggesting that it encodes a novel enzyme that cleaves this intermediate. We isolated the H. pylori gene encoding this enzyme, bioV, by complementation of an E. coli bioH deletion strain. Purified BioV cleaved the physiological substrate, pimeloyl-ACP methyl ester to pimeloyl-ACP by use of a catalytic triad, each member of which was essential for activity. The role of BioV in biotin biosynthesis was demonstrated using a reconstituted in vitro desthiobiotin synthesis system. BioV homologues seem the sole pimeloyl-ACP methyl ester esterase present in the Helicobacter species and their occurrence only in H. pylori and close relatives provide a target for development of drugs to specifically treat Helicobacter infections.

  2. Tyramine and phenylethylamine biosynthesis by food bacteria.

    Science.gov (United States)

    Marcobal, Angela; De las Rivas, Blanca; Landete, José María; Tabera, Laura; Muñoz, Rosario

    2012-01-01

    Tyramine poisoning is caused by the ingestion of food containing high levels of tyramine, a biogenic amine. Any foods containing free tyrosine are subject to tyramine formation if poor sanitation and low quality foods are used or if the food is subject to temperature abuse or extended storage time. Tyramine is generated by decarboxylation of the tyrosine through tyrosine decarboxylase (TDC) enzymes derived from the bacteria present in the food. Bacterial TDC have been only unequivocally identified and characterized in Gram-positive bacteria, especially in lactic acid bacteria. Pyridoxal phosphate (PLP)-dependent TDC encoding genes (tyrDC) appeared flanked by a similar genetic organization in several species of lactic acid bacteria, suggesting a common origin by a single mobile genetic element. Bacterial TDC are also able to decarboxylate phenylalanine to produce phenylethylamine (PEA), another biogenic amine. The molecular knowledge of the genes involved in tyramine production has led to the development of molecular methods for the detection of bacteria able to produce tyramine and PEA. These rapid and simple methods could be used for the analysis of the ability to form tyramine by bacteria in order to evaluate the potential risk of tyramine biosynthesis in food products.

  3. Biosynthesis of secondary metabolites in sugarcane

    Directory of Open Access Journals (Sweden)

    S.C. França

    2001-12-01

    Full Text Available A set of genes related to secondary metabolism was extracted from the sugarcane expressed sequence tag (SUCEST database and was used to investigate both the gene expression pattern of key enzymes regulating the main biosynthetic secondary metabolism pathways and the major classes of metabolites involved in the response of sugarcane to environmental and developmental cues. The SUCEST database was constructed with tissues in different physiological conditions which had been collected under varied situation of environmental stress. This database allows researchers to identify and characterize the expressed genes of a wide range of putative enzymes able to catalyze steps in the phenylpropanoid, isoprenoid and other pathways of the special metabolic mechanisms involved in the response of sugarcane to environmental changes. Our results show that sugarcane cDNAs encoded putative ultra-violet induced sesquiterpene cyclases (SC; chalcone synthase (CHS, the first enzyme in the pathway branch for flavonoid biosynthesis; isoflavone synthase (IFS, involved in plant defense and root nodulation; isoflavone reductase (IFR, a key enzyme in phenylpropanoid phytoalexin biosynthesis; and caffeic acid-O-methyltransferase, a key enzyme in the biosynthesis of lignin cell wall precursors. High levels of CHS transcripts from plantlets infected with Herbaspirillum rubri or Gluconacetobacter diazotroficans suggests that agents of biotic stress can elicit flavonoid biosynthesis in sugarcane. From this data we have predicted the profile of isoprenoid and phenylpropanoid metabolism in sugarcane and pointed the branches of secondary metabolism activated during tissue-specific stages of development and the adaptive response of sugarcane to agents of biotic and abiotic stress, although our assignment of enzyme function should be confirmed by careful biochemical and genetic supporting evidence.Este trabalho foi realizado com os objetivos de gerar uma coleção de genes

  4. Expanding ester biosynthesis in Escherichia coli.

    Science.gov (United States)

    Rodriguez, Gabriel M; Tashiro, Yohei; Atsumi, Shota

    2014-04-01

    To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l(-1)). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.

  5. Biosynthesis of Silver Nanoparticles Using Chenopodium ambrosioides

    Directory of Open Access Journals (Sweden)

    Luis M. Carrillo-López

    2014-01-01

    Full Text Available Biosynthesis of silver nanoparticles (AgNPs was achieved using extract of Chenopodium ambrosioides as a reducer and coating agent at room temperature (25°C. Two molar solutions of AgNO3 (1 mM and 10 mM and five extract volumes (0.5, 1, 2, 3, and 5 mL were used to assess quantity, shape, and size of the particles. The UV-Vis spectra gave surface plasmon resonance at 434–436 nm of the NPs synthesized with AgNO3 10 mM and all extract volumes tested, showing a direct relationship between extract volumes and quantity of particles formed. In contrast, the concentration of silver ions was related negatively to particle size. The smallest (4.9 ± 3.4 nm particles were obtained with 1 mL of extract in AgNO3 10 mM and the larger amount of particles were obtained with 2 mL and 5 mL of extract. TEM study indicated that the particles were polycrystalline and randomly oriented with a silver structure face centered cubic (fcc and fourier transform infrared spectroscopy (FTIR indicated that disappearance of the –OH group band after bioreduction evidences its role in reducing silver ions.

  6. Aspects of tobacco diterpene biosynthesis and accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Keene, C.K.

    1985-01-01

    Lamina, midveins, stalks and flowers of most Nicotiana species are covered with trichomes. The exudate which accumulates around glandular trichome heads has been suggested to be responsible for the characteristics flavor and aroma associated with different tobaccos. Many classes of compounds have been identified in cuticular surface washes and exudates of tobacco, in particular diterpenes such as the labdanes and duvanes. It has been assumed that most of the components present in the cuticular surface washes and trichome exudates are synthesized by the trichomes. However, there is little definitive evidence to support this assumption. Utilizing radiolabeled precursors, studies were undertaken to determine the site or sites of 1S- and 1R-4.8, 13-duvatriene-1,3-diol (1S- and 1R-diol) biosynthesis. Experiments using midvein sections of Tobacco Introduction 1068 treated with (2-/sup 14/C)acetate or mevalonic acid indicated that radioactivity was incorporated into surface components, including 1S- and 1R-diol. Subsequent experiments demonstrated that all of the labeled duvatrienediols found were associated with the exudate and surface extracts. Experiments using incubated detached glandular trichome heads unequivocally demonstrated that the glandular heads have the biosynthetic capacity to incorporate (2-/sup 14/C)acetate or mevalonic acid into 1S- and 1R-diol. The influence of nitrogen fertilization, water stress, time of topping and curing conditions on the accumulated levels of 1S- and 1R-diol in field grown Ky 14 was also examined.

  7. Plant cuticles: physicochemical characteristics and biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Holloway, P.J. [Dept. of Agricultural Sciences, Univ. of Bristol, AFRC Inst. of Arable Crops Research (United Kingdom)

    1994-12-31

    Cuticles are the thin continuous layers of predominantly lipid material deposited on the outer walls of epidermal cells and, thus, the interface between higher plants and their aerial environment. The main function of this extracellular, non-living layer, commonly referred to as a membrane, is to protect and waterproof the plant surface. Although not structurally or chemically homogeneous, cuticles are usually characterised by two specific classes of lipid substances. The insoluble high molecular weight polyester cutins constitute the framework of the membrane, the monomeric units of which are biosynthesised in the epidermal cells from C{sub 16} and C{sub 18} fatty acid precursors. The soluble long-chain wax constituents are also synthesised by these cells and are eventually deposited not only on the cuticular surface but also within the cutin matrix. Epicuticular waxes have a considerable influence on the wettability of a plant surface whereas the presence of intracuticular waxes governs cuticular permeability. The cuticles of some species also contain variable amounts of another aliphatic biopolymer, cutin, which is non-saponifiable and, consequently, extremely resistant to biodegradation. Because the cuticle is an integral part of the epidermal cell wall, polysaccharides and probably, phenolic compounds are also involved in its construction. The current status of our fundamental knowledge about the structure, chemical composition, and biosynthesis of plant cuticles will be reviewed in order to highlight the nature of potential sites for interaction with air pollutants. (orig.)

  8. Biosynthesis of active pharmaceuticals: β-lactam biosynthesis in filamentous fungi.

    Science.gov (United States)

    Van Den Berg, Marco; Gidijala, Loknath; Kiela, Jan; Bovenberg, Roel; Vander Keli, Ida

    2010-01-01

    β-lactam antibiotics (e.g. penicillins, cephalosporins) are of major clinical importance and contribute to over 40% of the total antibiotic market. These compounds are produced as secondary metabolites by certain actinomycetes and filamentous fungi (e.g. Penicillium, Aspergillus and Acremonium species). The industrial producer of penicillin is the fungus Penicillium chrysogenum. The enzymes of the penicillin biosynthetic pathway are well characterized and most of them are encoded by genes that are organized in a cluster in the genome. Remarkably, the penicillin biosynthetic pathway is compartmentalized: the initial steps of penicillin biosynthesis are catalyzed by cytosolic enzymes, whereas the two final steps involve peroxisomal enzymes. Here, we describe the biochemical properties of the enzymes of β-lactam biosynthesis in P. chrysogenum and the role of peroxisomes in this process. An overview is given on strain improvement programs via classical mutagenesis and, more recently, genetic engineering, leading to more productive strains. Also, the potential of using heterologous hosts for the development of novel ß-lactam antibiotics and non-ribosomal peptide synthetase-based peptides is discussed.

  9. Complexity of the transcriptional network controlling secondary wall biosynthesis.

    Science.gov (United States)

    Zhong, Ruiqin; Ye, Zheng-Hua

    2014-12-01

    Secondary walls in the form of wood and fibers are the most abundant biomass produced by vascular plants, and are important raw materials for many industrial uses. Understanding how secondary walls are constructed is of significance in basic plant biology and also has far-reaching implications in genetic engineering of plant biomass better suited for various end uses, such as biofuel production. Secondary walls are composed of three major biopolymers, i.e., cellulose, hemicelluloses and lignin, the biosynthesis of which requires the coordinated transcriptional regulation of all their biosynthesis genes. Genomic and molecular studies have identified a number of transcription factors, whose expression is associated with secondary wall biosynthesis. We comprehensively review how these secondary wall-associated transcription factors function together to turn on the secondary wall biosynthetic program, which leads to secondary wall deposition in vascular plants. The transcriptional network regulating secondary wall biosynthesis employs a multi-leveled feed-forward loop regulatory structure, in which the top-level secondary wall NAC (NAM, ATAF1/2 and CUC2) master switches activate the second-level MYB master switches and they together induce the expression of downstream transcription factors and secondary wall biosynthesis genes. Secondary wall NAC master switches and secondary wall MYB master switches bind to and activate the SNBE (secondary wall NAC binding element) and SMRE (secondary wall MYB-responsive element) sites, respectively, in their target gene promoters. Further investigation of what and how developmental signals trigger the transcriptional network to regulate secondary wall biosynthesis and how different secondary wall-associated transcription factors function cooperatively in activating secondary wall biosynthetic pathways will lead to a better understanding of the molecular mechanisms underlying the transcriptional control of secondary wall biosynthesis.

  10. Soybean oil biosynthesis: role of diacylglycerol acyltransferases.

    Science.gov (United States)

    Li, Runzhi; Hatanaka, Tomoko; Yu, Keshun; Wu, Yongmei; Fukushige, Hirotada; Hildebrand, David

    2013-03-01

    Diacylglycerol acyltransferase (DGAT) catalyzes the acyl-CoA-dependent acylation of sn-1,2-diacylglycerol to form seed oil triacylglycerol (TAG). To understand the features of genes encoding soybean (Glycine max) DGATs and possible roles in soybean seed oil synthesis and accumulation, two full-length cDNAs encoding type 1 diacylglycerol acyltransferases (GmDGAT1A and GmDGAT1B) were cloned from developing soybean seeds. These coding sequences share identities of 94 % and 95 % in protein and DNA sequences. The genomic architectures of GmDGAT1A and GmDGAT1B both contain 15 introns and 16 exons. Differences in the lengths of the first exon and most of the introns were found between GmDGAT1A and GmDGAT1B genomic sequences. Furthermore, detailed in silico analysis revealed a third predicted DGAT1, GmDGAT1C. GmDGAT1A and GmDGAT1B were found to have similar activity levels and substrate specificities. Oleoyl-CoA and sn-1,2-diacylglycerol were preferred substrates over vernoloyl-CoA and sn-1,2-divernoloylglycerol. Both transcripts are much more abundant in developing seeds than in other tissues including leaves, stem, roots, and flowers. Both soybean DGAT1A and DGAT1B are highly expressed at developing seed stages of maximal TAG accumulation with DGAT1B showing highest expression at somewhat later stages than DGAT1A. DGAT1A and DGAT1B show expression profiles consistent with important roles in soybean seed oil biosynthesis and accumulation.

  11. Biosynthesis and functions of sulfur modifications in tRNA

    Directory of Open Access Journals (Sweden)

    Naoki eShigi

    2014-04-01

    Full Text Available Sulfur is an essential element for a variety of cellular constituents in all living organisms. In tRNA molecules, there are many sulfur-containing nucleosides, such as the derivatives of 2‑thiouridine (s2U, 4-thiouridine (s4U, 2-thiocytidine (s2C, and 2-methylthioadenosine (ms2A. Earlier studies established the functions of these modifications for accurate and efficient translation, including proper recognition of the codons in mRNA or stabilization of tRNA structure. In many cases, the biosynthesis of these sulfur modifications starts with cysteine desulfurases, which catalyze the generation of persulfide (an activated form of sulfur from cysteine. Many sulfur-carrier proteins are responsible for delivering this activated sulfur to each biosynthesis pathway. Finally, specific modification enzymes activate target tRNAs and then incorporate sulfur atoms. Intriguingly, the biosynthesis of 2-thiouridine in all domains of life is functionally and evolutionarily related to the ubiquitin-like post-translational modification system of cellular proteins in eukaryotes. This review summarizes the recent characterization of the biosynthesis of sulfur modifications in tRNA and the novel roles of this modification in cellular functions in various model organisms, with a special emphasis on 2-thiouridine derivatives. Each biosynthesis pathway of sulfur-containing molecules is mutually modulated via sulfur trafficking, and 2-thiouridine and codon usage bias have been proposed to control the translation of specific genes.

  12. Terpenoid Indole Alkaloids Biosynthesis and Metabolic Engineering in Catharanthus roseus

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Catharanthus roseus L. (Madagascar periwinkle) biosynthesizes a diverse array of secondary metabolites including anticancer dimeric alkaloids (vinblastine and vincristine) and antihypertensive alkaloids (ajmalicine and serpentine). The multi-step terpenoid indole alkaloids (TIAs) biosynthetic pathway in C. roseus is complex and is under strict molecular regulation. Many enzymes and genes involved in the TIAs biosynthesis have been studied in recent decades. Moreover,some regulatory proteins were found recently to control the production of TIAs in C. roseus. Based on mastering the rough scheme of the pathway and cloning the related genes, metabolic engineering of TIAs biosynthesis has been studied in C.roseus aiming at increasing the desired secondary metabolites in the past few years. The present article summarizes recent advances in isolation and characterization of TIAs biosynthesis genes and transcriptional regulators involved in the second metabolic control in C. roseus. Metabolic engineering applications in TIAs pathway via overexpression of these genes and regulators in C. roseus are also discussed.

  13. Clavulanic acid biosynthesis and genetic manipulation for its overproduction.

    Science.gov (United States)

    Song, Ju Yeon; Jensen, Susan E; Lee, Kye Joon

    2010-10-01

    Clavulanic acid, a β-lactamase inhibitor, is used together with β-lactam antibiotics to create drug mixtures possessing potent antimicrobial activity. In view of the clinical and industrial importance of clavulanic acid, identification of the clavulanic acid biosynthetic pathway and the associated gene cluster(s) in the main producer species, Streptomyces clavuligerus, has been an intriguing research question. Clavulanic acid biosynthesis was revealed to involve an interesting mechanism common to all of the clavam metabolites produced by the organism, but different from that of other β-lactam compounds. Gene clusters involved in clavulanic acid biosynthesis in S. clavuligerus occupy large regions of nucleotide sequence in three loci of its genome. In this review, clavulanic acid biosynthesis and the associated gene clusters are discussed, and clavulanic acid improvement through genetic manipulation is explained.

  14. Inhibitors of amino acids biosynthesis as antifungal agents.

    Science.gov (United States)

    Jastrzębowska, Kamila; Gabriel, Iwona

    2015-02-01

    Fungal microorganisms, including the human pathogenic yeast and filamentous fungi, are able to synthesize all proteinogenic amino acids, including nine that are essential for humans. A number of enzymes catalyzing particular steps of human-essential amino acid biosynthesis are fungi specific. Numerous studies have shown that auxotrophic mutants of human pathogenic fungi impaired in biosynthesis of particular amino acids exhibit growth defect or at least reduced virulence under in vivo conditions. Several chemical compounds inhibiting activity of one of these enzymes exhibit good antifungal in vitro activity in minimal growth media, which is not always confirmed under in vivo conditions. This article provides a comprehensive overview of the present knowledge on pathways of amino acids biosynthesis in fungi, with a special emphasis put on enzymes catalyzing particular steps of these pathways as potential targets for antifungal chemotherapy.

  15. Recent advances in combinatorial biosynthesis for drug discovery

    Directory of Open Access Journals (Sweden)

    Sun H

    2015-02-01

    Full Text Available Huihua Sun,1,* Zihe Liu,1,* Huimin Zhao,1,2 Ee Lui Ang1 1Metabolic Engineering Research Laboratory, Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, Singapore; 2Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA *These authors contributed equally to this work Abstract: Because of extraordinary structural diversity and broad biological activities, natural products have played a significant role in drug discovery. These therapeutically important secondary metabolites are assembled and modified by dedicated biosynthetic pathways in their host living organisms. Traditionally, chemists have attempted to synthesize natural product analogs that are important sources of new drugs. However, the extraordinary structural complexity of natural products sometimes makes it challenging for traditional chemical synthesis, which usually involves multiple steps, harsh conditions, toxic organic solvents, and byproduct wastes. In contrast, combinatorial biosynthesis exploits substrate promiscuity and employs engineered enzymes and pathways to produce novel “unnatural” natural products, substantially expanding the structural diversity of natural products with potential pharmaceutical value. Thus, combinatorial biosynthesis provides an environmentally friendly way to produce natural product analogs. Efficient expression of the combinatorial biosynthetic pathway in genetically tractable heterologous hosts can increase the titer of the compound, eventually resulting in less expensive drugs. In this review, we will discuss three major strategies for combinatorial biosynthesis: 1 precursor-directed biosynthesis; 2 enzyme-level modification, which includes swapping of the entire domains, modules and subunits, site-specific mutagenesis, and directed evolution; 3 pathway-level recombination. Recent examples of combinatorial biosynthesis employing these

  16. Molecular Evidences for the Biosynthesis of Pederin by Endosymbiont

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-ping; WU Xuan; WANG Jin-jun; HUANG Fang

    2009-01-01

    Pederin belongs to a group of antitumor compounds found in terrestrial beetles and marine sponges. It is apparently used by some members of the rove beetle Paederus as a chemical defense against predators. A recent cluster analysis of the putative pederin biosynthesis gene (ped) strongly suggests that pederin is produced by bacterial symbionts. This paper reviewed the criteria for proving symbiontic origin of bioactive metabolite, indirect and molecular evidences for pederin bacterial origin, as well as three sets ofped clusters and putative biosynthesis process of pederin.

  17. Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides.

    Science.gov (United States)

    Hemmerling, Franziska; Hahn, Frank

    2016-01-01

    This review highlights the biosynthesis of heterocycles in polyketide natural products with a focus on oxygen and nitrogen-containing heterocycles with ring sizes between 3 and 6 atoms. Heterocycles are abundant structural elements of natural products from all classes and they often contribute significantly to their biological activity. Progress in recent years has led to a much better understanding of their biosynthesis. In this context, plenty of novel enzymology has been discovered, suggesting that these pathways are an attractive target for future studies.

  18. Pseudopterosin Biosynthesis: Aromatization of the Diterpene Cyclase Product, Elisabethatriene

    Directory of Open Access Journals (Sweden)

    Amber C. Kohl

    2003-11-01

    Full Text Available Abstract: Putative precursors in pseudopterosin biosynthesis, the hydrocarbons isoelisabethatriene (10 and erogorgiaene (11, have been identified from an extract of Pseudopterogorgia elisabethae collected in the Florida Keys. Biosynthetic experiments designed to test the utilization of these compounds in pseudopterosin production revealed that erogorgiaene is transformed to pseudopterosins A-D. Together with our previous data, it is now apparent that early steps in pseudopterosin biosynthesis involve the cyclization of geranylgeranyl diphosphate to elisabethatriene followed by the dehydrogenation and aromatization to erogorgiaene.

  19. Final Report on Regulation of Guaiacyl and Syringyl Monolignol Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Vincent L. Chiang

    2006-03-09

    The focus of this research is to understand syringyl monolignol biosynthesis that leads to the formation of syringyl lignin, a type of lignin that can be easily removed during biomass conversion. We have achieved the three originally proposed goals for this project. (1) SAD and CAD genes (enzyme catalytic and kinetic properties) and their functional relevance to CAld5H/AldOMT pathway, (2) spatiotemporal expression patterns of Cald5H, AldOMT, SAD and CAD genes, and (3) functions of CAld5H, AldOMT, and SAD genes in vivo using transgenic aspen. Furthermore, we also found that microRNA might be involved in the upstream regulatory network of lignin biosynthesis and wood formation. The achievements are as below. (1) Based on biochemical and molecular studies, we discovered a novel syringyl-specific alcohol dehydrogenase (SAD) involved in monolignol biosynthesis in angiosperm trees. Through CAld5H/OMT/SAD mediation, syringyl monolignol biosynthesis branches out from guaiacyl pathway at coniferaldehyde; (2) The function of CAld5H gene in this syringyl monolignol biosynthesis pathway also was confirmed in vivo in transgenic Populus; (3) The proposed major monolignol biosynthesis pathways were further supported by the involving biochemical functions of CCR based on a detailed kinetic study; (4) Gene promoter activity analysis also supported the cell-type specific expression of SAD and CAD genes in xylem tissue, consistent with the cell-specific locations of SAD and CAD proteins and with the proposed pathways; (5) We have developed a novel small interfering RNA (siRNA)-mediated stable gene-silencing system in transgenic plants; (6) Using the siRNA and P. trichocarpa transformation/regeneration systems we are currently producing transgenic P. trichocarpa to investigate the interactive functions of CAD and SAD in regulating guaiacyl and syringyl lignin biosynthesis; (7) We have cloned for the first time from a tree species, P. trichocarpa, small regulatory RNAs termed micro

  20. [Snake venom metalloproteinases: structure, biosynthesis and function(s)].

    Science.gov (United States)

    Limam, I; El Ayeb, M; Marrakchi, N

    2010-01-01

    The biochemical and the pharmacological characterization of snake venoms revealed an important structural and functional polymorphism of proteins which they contain. Among them, snake venom metalloproteases (SVMPs) constitute approximatively 20 to 60% of the whole venom proteins. During the last decades, a significant progress was performed against structure studies and the biosynthesis of the SVMPs. Indeed, several metalloproteases were isolated and characterized against their structural and pharmacological properties. In this review, we report the most important properties concerning the classification, the structure of the various domains of the SVMPs as well as their biosynthesis and their activities as potential therapeutic agents.

  1. Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

    Science.gov (United States)

    Hemmerling, Franziska

    2016-01-01

    Summary This review highlights the biosynthesis of heterocycles in polyketide natural products with a focus on oxygen and nitrogen-containing heterocycles with ring sizes between 3 and 6 atoms. Heterocycles are abundant structural elements of natural products from all classes and they often contribute significantly to their biological activity. Progress in recent years has led to a much better understanding of their biosynthesis. In this context, plenty of novel enzymology has been discovered, suggesting that these pathways are an attractive target for future studies. PMID:27559404

  2. Cephamycin C biosynthesis in Streptomyces cattleya: nitrogen source regulation.

    Science.gov (United States)

    Khaoua, S; Lebrihi, A; Germain, P; Lefebvre, G

    1991-05-01

    The production of cephamycin C by Streptomyces cattleya varies with the use of asparagine, glutamine or ammonium as nitrogen sources. Hydroxylase and expandase activities were demonstrated for the first time with this species. A study of the biosynthetic regulation of these enzymes by two different nitrogen sources, glutamine and asparagine, was carried out. Asparagine proved to be a better nitrogen source, both for enzymatic biosynthesis and production of cephamycin C. Moreover, an excess of asparagine in the culture environment provokes, simultaneously, a reduction in cephamycin C production and a decrease in the biosynthesis of expandase and hydroxylase.

  3. Regulation of succinoglycan and galactoglucan biosynthesis in Sinorhizobium meliloti.

    Science.gov (United States)

    Becker, Anke; Rüberg, Silvia; Baumgarth, Birgit; Bertram-Drogatz, Peter Alexander; Quester, Ingmar; Pühler, Alfred

    2002-05-01

    Sinorhizobium meliloti (Rhizobium meliloti) 2011 has the ability to produce the two acidic exopolysaccharides succinoglycan (EPS I) and galactoglucan (EPS II). EPS I is a branched heteropolysaccharide composed of octasaccharide repeating units, whereas EPS II is a linear heteropolysaccharide consisting of disaccharide subunits. The exo-exs and exp gene clusters are involved in the biosynthesis of EPSI and EPSII, respectively. EPSI and EPSII biosynthesis genes are differentially expressed resulting in a complex regulation of EPS production in S. meliloti. The phosphate concentration was identified as an important factor affecting the expression of exp genes.

  4. Biotin biosynthesis in Mycobacterium tuberculosis: physiology, biochemistry and molecular intervention

    Institute of Scientific and Technical Information of China (English)

    Wanisa Salaemae; Al Azhar; Grant W. Booker; Steven W. Polyak

    2011-01-01

    Biotin is an important micronutrient that serves as an essential enzyme cofactor.Bacteria obtain biotin either through de novo synthesis or by active uptake from exogenous sources.Mycobacteria are unusual amongst bacteria in that their primary source of biotin is through de novo synthesis.Here we review the importance of biotin biosynthesis in the lifecycle of Mycobacteria.Genetic screens designed to identify key metabolic processes have highlighted a role for the biotin biosynthesis in bacilli growth,infection and survival during the latency phase.These studies help to establish the biotin biosynthetic pathway as a potential drug target for new anti-tuberculosis agents.

  5. [Biosynthesis of biologically active low-molecular weight compounds by fungi of the genus Penicillium (review)].

    Science.gov (United States)

    Kozlovskii, A G; Antipova, T V; Zhelifonova, V P

    2015-01-01

    The recent data on exometabolite biosynthesis in fungi of the genus Penicillium is summarized. The study of creative species, as well as those isolated from extreme ecotopes, resulted in the identification of a number of novel, biologically active compounds. Alkaloid biosynthesis has been shown to begin on.the first day of fungus cultivation and to proceed throughout the cultivation period. Idiophase kinetics was observed for the biosynthesis of polyketide metabolites. The mechanisms of regulation of biosynthesis of promising bioactive compounds are discussed.

  6. Visnagin: biosynthesis and isolation from Ammi visnagi suspension cultures.

    Science.gov (United States)

    Kaul, B; Staba, E J

    1965-12-24

    During an examination of Ammi visnaga Lam. suspension cultures for the biosynthesis of furanochromones and related medicinal compounds, visnagin was isolated in crystalline form and identified. Thus, certain medicinally important secondary plant metabolites may be produced in appreciable amounts by plant tissue cultures.

  7. Analyzing the complex machinery of cell wall biosynthesis

    NARCIS (Netherlands)

    Timmers, J.F.P.

    2009-01-01

    The plant cell wall polymers make up most of the plant biomass and provide the raw material for many economically important products including food, feed, bio-materials, chemicals, textiles, and biofuel. This broad range of functions and applications make the biosynthesis of these polysaccharides a

  8. Effect of Light on Flavonoids Biosynthesis in Red Rice Rdh

    Institute of Scientific and Technical Information of China (English)

    HAN Lei; DONG Bao-cheng; YANG Xiao-ji; HUANG Cheng-bin; WANG Xu-dong; WU Xian-jun

    2009-01-01

    The effect of light on flavonoids biosynthesis in red rice Rdh was studied.The panicles of red rice Rdh produced colorless caryopses after darkness treatment;and these colorless caryopses displayed bright-red after vanillin treatment,but did not display red color after light inducing for 15 days,suggesting that red rice Rdh could produce leucoanthocyanidin,but could not produce polyproanthocyanidins in darkness.Histological study revealed that the aleurone layers of Rdh colorless caryopses displayed bright-red after vanillin assay,but the pericarp and seed coat layers did not display color change,which indicated that the aleurone layers could accumulate precursors of polyproanthocyanidins in darkness,but the pericarp and seed coat could not.Additionally,color ofRdh caryopses changed from green in immaturity to red in maturity,and the green caryopses changed color from green to red gradually indoor for 7 days after harvest,suggesting that leucoanthocyanidins could synthesize polyproanthocyanidins.It was concluded that light was necessary for red pigment biosynthesis in red rice Rdh,leucoanthocyanidins biosyntheses in the aleurone layers did not need light,leucoanthocyanidins biosynthesis in pericarp and seed coat needed light inducing,the effect of leucoanthocyanidin biosynthesis in Rdh to light had tissue specificity.

  9. Molecular Basis for Mycophenolic Acid Biosynthesis in Penicillium brevicompactum

    DEFF Research Database (Denmark)

    Regueira, Torsten Ulrik Bak; Kildegaard, Kanchana Rueksomtawin; Hansen, Bjarne Gram;

    2011-01-01

    Mycophenolic acid (MPA) is the active ingredient in the increasingly important immunosuppressive pharmaceuticals CellCept (Roche) and Myfortic (Novartis). Despite the long history of MPA, the molecular basis for its biosynthesis has remained enigmatic. Here we report the discovery of a polyketide...

  10. Biosynthesis of polyketides by trans-AT polyketide synthases.

    Science.gov (United States)

    Piel, Jörn

    2010-07-01

    This review discusses the biosynthesis of natural products that are generated by trans-AT polyketide synthases, a family of catalytically versatile enzymes that have recently been recognized as one of the major group of proteins involved in the production of bioactive polyketides. 436 references are cited.

  11. Brassinosteroids Are Master Regulators of Gibberellin Biosynthesis in Arabidopsis

    Science.gov (United States)

    Unterholzner, Simon J.; Rozhon, Wilfried; Papacek, Michael; Ciomas, Jennifer; Lange, Theo; Kugler, Karl G.; Mayer, Klaus F.; Sieberer, Tobias; Poppenberger, Brigitte

    2015-01-01

    Plant growth and development are highly regulated processes that are coordinated by hormones including the brassinosteroids (BRs), a group of steroids with structural similarity to steroid hormones of mammals. Although it is well understood how BRs are produced and how their signals are transduced, BR targets, which directly confer the hormone’s growth-promoting effects, have remained largely elusive. Here, we show that BRs regulate the biosynthesis of gibberellins (GAs), another class of growth-promoting hormones, in Arabidopsis thaliana. We reveal that Arabidopsis mutants deficient in BR signaling are severely impaired in the production of bioactive GA, which is correlated with defective GA biosynthetic gene expression. Expression of the key GA biosynthesis gene GA20ox1 in the BR signaling mutant bri1-301 rescues many of its developmental defects. We provide evidence that supports a model in which the BR-regulated transcription factor BES1 binds to a regulatory element in promoters of GA biosynthesis genes in a BR-induced manner to control their expression. In summary, our study underscores a role of BRs as master regulators of GA biosynthesis and shows that this function is of major relevance for the growth and development of vascular plants. PMID:26243314

  12. Shedding light on ovothiol biosynthesis in marine metazoans

    Science.gov (United States)

    Castellano, Immacolata; Migliaccio, Oriana; D’Aniello, Salvatore; Merlino, Antonello; Napolitano, Alessandra; Palumbo, Anna

    2016-02-01

    Ovothiol, isolated from marine invertebrate eggs, is considered one of the most powerful antioxidant with potential for drug development. However, its biological functions in marine organisms still represent a matter of debate. In sea urchins, the most accepted view is that ovothiol protects the eggs by the high oxidative burst at fertilization. In this work we address the role of ovothiol during sea urchin development to give new insights on ovothiol biosynthesis in metazoans. The gene involved in ovothiol biosynthesis OvoA was identified in Paracentrotus lividus genome (PlOvoA). PlOvoA embryo expression significantly increased at the pluteus stage and was up-regulated by metals at concentrations mimicking polluted sea-water and by cyclic toxic algal blooms, leading to ovothiol biosynthesis. In silico analyses of the PlOvoA upstream region revealed metal and stress responsive elements. Structural protein models highlighted conserved active site residues likely responsible for ovothiol biosynthesis. Phylogenetic analyses indicated that OvoA evolved in most marine metazoans and was lost in bony vertebrates during the transition from the aquatic to terrestrial environment. These results highlight the crucial role of OvoA in protecting embryos released in seawater from environmental cues, thus allowing the survival under different conditions.

  13. Cholesterol biosynthesis and homeostasis in regulation of the cell cycle.

    Directory of Open Access Journals (Sweden)

    Pushpendra Singh

    Full Text Available The cell cycle is a ubiquitous, multi-step process that is essential for growth and proliferation of cells. The role of membrane lipids in cell cycle regulation is not explored well, although a large number of cytoplasmic and nuclear regulators have been identified. We focus in this work on the role of membrane cholesterol in cell cycle regulation. In particular, we have explored the stringency of the requirement of cholesterol in the regulation of cell cycle progression. For this purpose, we utilized distal and proximal inhibitors of cholesterol biosynthesis, and monitored their effect on cell cycle progression. We show that cholesterol content increases in S phase and inhibition of cholesterol biosynthesis results in cell cycle arrest in G1 phase under certain conditions. Interestingly, G1 arrest mediated by cholesterol biosynthesis inhibitors could be reversed upon metabolic replenishment of cholesterol. Importantly, our results show that the requirement of cholesterol for G1 to S transition is absolute, and even immediate biosynthetic precursors of cholesterol, differing with cholesterol merely in a double bond, could not replace cholesterol for reversing the cell cycle arrest. These results are useful in the context of diseases, such as cancer and Alzheimer's disease, that are associated with impaired cholesterol biosynthesis and homeostasis.

  14. Biosynthesis of a thiamin antivitamin in Clostridium botulinum.

    Science.gov (United States)

    Cooper, Lisa E; O'Leary, Seán E; Begley, Tadhg P

    2014-04-15

    Bacimethrin-derived 2'-methoxythiamin pyrophosphate inhibits microbial growth by disrupting metabolic pathways dependent on thiamin-utilizing enzymes. This study describes the discovery of the bacimethrin biosynthetic gene cluster of Clostridium botulinum A ATCC 19397 and in vitro reconstitution of bacimethrin biosynthesis from cytidine 5'-monophosphate.

  15. Roles of tRNA in cell wall biosynthesis

    DEFF Research Database (Denmark)

    Dare, Kiley; Ibba, Michael

    2012-01-01

    Recent research into various aspects of bacterial metabolism such as cell wall and antibiotic synthesis, degradation pathways, cellular stress, and amino acid biosynthesis has elucidated roles of aminoacyl-transfer ribonucleic acid (aa-tRNA) outside of translation. Although the two enzyme families...

  16. A biosynthesis view on nutrient stress in coastal phytoplankton

    NARCIS (Netherlands)

    Grosse, J.; van Breugel, P.; Brussaard, C.P.D.; Boschker, H.T.S.

    2016-01-01

    Anthropogenic activities resulted in major shifts in nutrient inputs to coastal seas, which may have alteredthe biomolecule composition of phytoplankton because of different C : N : P requirements for biosynthesis.In order to understand the effects of N- and P-limitation on the allocation of photosy

  17. Labelling studies on the biosynthesis of terpenes in Fusarium fujikuroi.

    Science.gov (United States)

    Citron, Christian A; Brock, Nelson L; Tudzynski, Bettina; Dickschat, Jeroen S

    2014-05-25

    Synthetic [2-(13)C]mevalonolactone was fed to the gibberellin producer Fusarium fujikuroi and its incorporation into four known terpenoids was investigated by (13)C NMR analysis of crude culture extracts. The experiments gave detailed insights into the mechanisms of terpene biosynthesis by this fungus.

  18. FUNCTIONAL SPECIALIZATION OF DUPLICATED FLAVONOID BIOSYNTHESIS GENES IN WHEAT

    Directory of Open Access Journals (Sweden)

    Khlestkina E.

    2012-08-01

    Full Text Available Gene duplication followed by subfunctionalization and neofunctionalization is of a great evolutionary importance. In plant genomes, duplicated genes may result from either polyploidization (homoeologous genes or segmental chromosome duplications (paralogous genes. In allohexaploid wheat Triticum aestivum L. (2n=6x=42, genome BBAADD, both homoeologous and paralogous copies were found for the regulatory gene Myc encoding MYC-like transcriptional factor in the biosynthesis of flavonoid pigments, anthocyanins, and for the structural gene F3h encoding one of the key enzymes of flavonoid biosynthesis, flavanone 3-hydroxylase. From the 5 copies (3 homoeologous and 2 paralogous of the Myc gene found in T. aestivum, only one plays a regulatory role in anthocyanin biosynthesis, interacting complementary with another transcriptional factor (MYB-like to confer purple pigmentation of grain pericarp in wheat. The role and functionality of the other 4 copies of the Myc gene remain unknown. From the 4 functional copies of the F3h gene in T. aestivum, three homoeologues have similar function. They are expressed in wheat organs colored with anthocyanins or in the endosperm, participating there in biosynthesis of uncolored flavonoid substances. The fourth copy (the B-genomic paralogue is transcribed neither in wheat organs colored with anthocyanins nor in seeds, however, it’s expression has been noticed in roots of aluminium-stressed plants, where the three homoeologous copies are not active. Functional diversification of the duplicated flavonoid biosynthesis genes in wheat may be a reason for maintenance of the duplicated copies and preventing them from pseudogenization.The study was supported by RFBR (11-04-92707. We also thank Ms. Galina Generalova for technical assistance.

  19. Lipid biosynthesis pathways as chemotherapeutic targets in kinetoplastid parasites.

    Science.gov (United States)

    Urbina, J A

    1997-01-01

    Inhibitors of sterol and phospholipid biosynthesis in kinetoplastid parasites such as Trypanosoma cruzi, the causative agent of Chagas' disease, and different species of Leishmania have potent and selective activity as chemotherapeutic agents in vitro and in vivo. Recent work with the sterol C14 alpha-demethylase inhibitor D0870, a bis triazole derivative, showed that this compound is capable of inducing radical parasitological cure in murine models of both acute and chronic Chagas' disease. Other inhibitors of this type, such as SCH 56592, have also shown curative, rather than suppressive, activity against T. cruzi in these models. Leishmania species have different susceptibilities to sterol biosynthesis inhibitors, both in vitro and in vivo. Leishmania braziliensis promastigotes, naturally resistant to C14 alpha-demethylase inhibitors such as ketoconazole and D0870, were susceptible to these drugs when used in combination with the squalene epoxidase inhibitor terbinafine. Inhibitors of delta 24(25) sterol methyl transferase have been shown to act as potent antiproliferative agents against Trypanosoma cruzi, both in vitro and in vivo. New inhibitors of this type which show enhanced activity and novel mechanisms of action have been synthesized. Recent work has also demonstrated that this type of enzyme inhibitors can block sterol biosynthesis and cell proliferation in Pneumocystis carinii, a fungal pathogen which had previously been found resistant to other sterol biosynthesis inhibitors. Ajoene, an antiplatelet compound derived from garlic, was shown to have potent antiproliferative activity against epimastigotes and amastigotes of Trypanosoma cruzi in vitro; this activity was associated with a significant alteration of the phospholipid composition of the cells with no significant effects on the sterol content. In addition, alkyllsophospholipids such as ilmofosine, miltefosine and edelfosine have been shown to block the proliferation of T. cruzi and Leishmania and

  20. Characterization of an autoinducer of penicillin biosynthesis in Penicillium chrysogenum.

    Science.gov (United States)

    Martín, Jorge; García-Estrada, Carlos; Rumbero, Angel; Recio, Eliseo; Albillos, Silvia M; Ullán, Ricardo V; Martín, Juan-Francisco

    2011-08-15

    Filamentous fungi produce an impressive variety of secondary metabolites; many of them have important biological activities. The biosynthesis of these secondary metabolites is frequently induced by plant-derived external elicitors and appears to also be regulated by internal inducers, which may work in a way similar to that of bacterial autoinducers. The biosynthesis of penicillin in Penicillium chrysogenum is an excellent model for studying the molecular mechanisms of control of gene expression due to a good knowledge of the biochemistry and molecular genetics of β-lactam antibiotics and to the availability of its genome sequence and proteome. In this work, we first developed a plate bioassay that allows direct testing of inducers of penicillin biosynthesis using single colonies of P. chrysogenum. Using this bioassay, we have found an inducer substance in the conditioned culture broths of P. chrysogenum and Acremonium chrysogenum. No inducing effect was exerted by γ-butyrolactones, jasmonic acid, or the penicillin precursor δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine. The conditioned broth induced penicillin biosynthesis and transcription of the pcbAB, pcbC, and penDE genes when added at inoculation time, but its effect was smaller if added at 12 h and it had no effect when added at 24 h, as shown by Northern analysis and lacZ reporter studies. The inducer molecule was purified and identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR) as 1,3-diaminopropane. Addition of pure 1,3-diaminopropane stimulated the production of penicillin by about 100% compared to results for the control cultures. Genes for the biosynthesis of 1,3-diaminopropane have been identified in the P. chrysogenum genome.

  1. Increased sesquiterpenoid biosynthesis and an apparent decrease in sterol biosynthesis in elicitor-treated tobacco cell suspension cultures

    Energy Technology Data Exchange (ETDEWEB)

    Voegeli, U.; Bhatt, P.N.; Chappell, J.

    1987-04-01

    Addition of fungel elicitor prepared from Phytophthora parasitica to tobacco cell suspension cultures leads to an increased production of the phytoalexin capsidiol. Capsidiol is a sesquiterpenoid which is most likely synthesized from farnesylpyrophosphat (FPP) by a bicyclic cyclase reaction. Because FPP is also a substrate for squalene synthetase and therefore a precursor of sterol biosynthesis, the question arises whether or not the accumulation of capsidiol in elicitor-treated cells occurs at the expense of sterol biosynthesis. (/sup 14/C)-acetate was given to elicitor-treated and control (no treatment) cell cultures and incorporation into sterols and capsidiol determined. No labeled capsidiol was detected in control cells. In elicitor-treated cells about 12-15% of the radioactivity taken up by the cells was incorporated into capsidiol. In contrast, control cells incorporated 4 times more radioactivity into sterols than elicitor-treated cells. Similar results were obtained using (/sup 3/H)-mevalonate as a precursor of capsidiol and sterol biosynthesis. Likely explanations for the apparently decline in sterol biosynthesis in elicitor-treated cells include: (1) inhibition of squalene synthetase; (2) induction of capsidiol synthesizing enzymes; and (3) metabolic channeling of FPP into capsidiol versus sterols. These possibilities will be discussed further together with other results.

  2. Regulatory cross-talks and cascades in rice hormone biosynthesis pathways contribute to stress signaling

    Directory of Open Access Journals (Sweden)

    Arindam Deb

    2016-08-01

    Full Text Available Crosstalk among different hormone signaling pathways play an important role in modulating plant response to both biotic and abiotic stress. Hormone activity is controlled by its bio-availability, which is again influenced by its biosynthesis. Thus independent hormone biosynthesis pathways must be regulated and co-ordinated to mount an integrated response. One of the possibilities is to use cis-regulatory elements to orchestrate expression of hormone biosynthesis genes. Analysis of CREs, associated with differentially expressed hormone biosynthesis related genes in rice leaf under Magnaporthe oryzae attack and drought stress enabled us to obtain insights about cross-talk among hormone biosynthesis pathways at the transcriptional level. We identified some master transcription regulators that co-ordinate different hormone biosynthesis pathways under stress. We found that Abscisic acid and Brassinosteroid regulate Cytokinin conjugation; conversely Brassinosteroid biosynthesis is affected by both Abscisic acid and Cytokinin. Jasmonic acid and Ethylene biosynthesis may be modulated by Abscisic acid through DREB transcription factors. Jasmonic acid or Salicylic acid biosynthesis pathways are co-regulated but they are unlikely to influence each other’s production directly. Thus multiple hormones may modulate hormone biosynthesis pathways through a complex regulatory network, where biosynthesis of one hormone is affected by several other contributing hormones.

  3. Regulatory Cross-Talks and Cascades in Rice Hormone Biosynthesis Pathways Contribute to Stress Signaling.

    Science.gov (United States)

    Deb, Arindam; Grewal, Rumdeep K; Kundu, Sudip

    2016-01-01

    Crosstalk among different hormone signaling pathways play an important role in modulating plant response to both biotic and abiotic stress. Hormone activity is controlled by its bio-availability, which is again influenced by its biosynthesis. Thus, independent hormone biosynthesis pathways must be regulated and co-ordinated to mount an integrated response. One of the possibilities is to use cis-regulatory elements to orchestrate expression of hormone biosynthesis genes. Analysis of CREs, associated with differentially expressed hormone biosynthesis related genes in rice leaf under Magnaporthe oryzae attack and drought stress enabled us to obtain insights about cross-talk among hormone biosynthesis pathways at the transcriptional level. We identified some master transcription regulators that co-ordinate different hormone biosynthesis pathways under stress. We found that Abscisic acid and Brassinosteroid regulate Cytokinin conjugation; conversely Brassinosteroid biosynthesis is affected by both Abscisic acid and Cytokinin. Jasmonic acid and Ethylene biosynthesis may be modulated by Abscisic acid through DREB transcription factors. Jasmonic acid or Salicylic acid biosynthesis pathways are co-regulated but they are unlikely to influence each others production directly. Thus, multiple hormones may modulate hormone biosynthesis pathways through a complex regulatory network, where biosynthesis of one hormone is affected by several other contributing hormones.

  4. Biosynthesis of Anthocyanins and Their Regulation in Colored Grapes

    Directory of Open Access Journals (Sweden)

    Guo-Liang Yan

    2010-12-01

    Full Text Available Anthocyanins, synthesized via the flavonoid pathway, are a class of crucial phenolic compounds which are fundamentally responsible for the red color of grapes and wines. As the most important natural colorants in grapes and their products, anthocyanins are also widely studied for their numerous beneficial effects on human health. In recent years, the biosynthetic pathway of anthocyanins in grapes has been thoroughly investigated. Their intracellular transportation and accumulation have also been further clarified. Additionally, the genetic mechanism regulating their biosynthesis and the phytohormone influences on them are better understood. Furthermore, due to their importance in the quality of wine grapes, the effects of the environmental factors and viticulture practices on anthocyanin accumulation are being investigated increasingly. The present paper summarizes both the basic information and the most recent advances in the study of the anthocyanin biosynthesis in red grapes, emphasizing their gene structure, the transcriptional factors and the diverse exterior regulation factors.

  5. Regulation of Isoprenoid Pheromone Biosynthesis in Bumblebee Males.

    Science.gov (United States)

    Prchalová, Darina; Buček, Aleš; Brabcová, Jana; Žáček, Petr; Kindl, Jiří; Valterová, Irena; Pichová, Iva

    2016-02-02

    Males of the closely related species Bombus terrestris and Bombus lucorum attract conspecific females by completely different marking pheromones. MP of B. terrestris and B. lucorum pheromones contain mainly isoprenoid (ISP) compounds and fatty acid derivatives, respectively. Here, we studied the regulation of ISP biosynthesis in both bumblebees. RNA-seq and qRT-PCR analyses indicated that acetoacetyl-CoA thiolase (AACT), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), and farnesyl diphosphate synthase (FPPS) transcripts are abundant in the B. terrestris labial gland. Maximal abundance of these transcripts correlated well with AACT enzymatic activity detected in the LG extracts. In contrast, transcript abundances of AACT, HMGR, and FPPS in B. lucorum were low, and AACT activity was not detected in LGs. These results suggest that transcriptional regulation plays a key role in the control of ISP biosynthetic gene expression and ISP pheromone biosynthesis in bumblebee males.

  6. Biosynthesis of glycosylated derivatives of tylosin in Streptomyces venezuelae.

    Science.gov (United States)

    Han, Ah Reum; Park, Sung Ryeol; Park, Je Won; Lee, Eun Yeol; Kim, Dong-Myung; Kim, Byung-Gee; Yoon, Yeo Joon

    2011-06-01

    Streptomyces venezuelae YJ028, bearing a deletion of the entire biosynthetic gene cluster encoding the pikromycin polyketide synthases and desosamine biosynthetic enzymes, was used as a bioconversion system for combinatorial biosynthesis of glycosylated derivatives of tylosin. Two engineered deoxysugar biosynthetic pathways for the biosynthesis of TDP-3-O-demethyl-D-chalcose or TDP-Lrhamnose in conjunction with the glycosyltransferaseauxiliary protein pair DesVII/DesVIII were expressed in a S. venezuelae YJ028 mutant strain. Supplementation of each mutant strain capable of producing TDP-3-O-demethyl- D-chalcose or TDP-L-rhamnose with tylosin aglycone tylactone resulted in the production of the 3-O-demethyl- D-chalcose, D-quinovose, or L-rhamnose-glycosylated tylactone.

  7. Effects of Co2+ on the erythromycin biosynthesis

    Institute of Scientific and Technical Information of China (English)

    DU Wen; CHEN Changhua

    2007-01-01

    Erythromycin biosynthesis is a highly complicated process,which involves both primary metabolism and secondary metabolism.The specific activities of the key enzymes related to glucose metabolism such as hexose kinase (HK),glucose-6-phosphate dehydrogenase(6-PDH),phosphofructokinase(PFK),and isocitrate dehydrogenase(ICD),were determined in Saccharopolyspora erythraea.The specitic activities of the enzymes involved in secondary metabolism,such as methylmalonyl-coenzyme A mutase (MCM)and methylmalonyl-coenzyme A transcarboxylase(MCT),were detected as well.Some organic acids contained in fermentation broth were also analyzed.The results show that Co2+ is able to increase erythromycin biosynthesis.It maybe due to Co2+ improving the specific activities of methylmalonyl-coenzyme A mutase and methylmalonyl-coenzyme A transcarboxylase.Meanwhile,it also enhances the flux of the glucose metabolism pathway.

  8. Enzymatic Reductive Dehalogenation Controls the Biosynthesis of Marine Bacterial Pyrroles.

    Science.gov (United States)

    El Gamal, Abrahim; Agarwal, Vinayak; Rahman, Imran; Moore, Bradley S

    2016-10-12

    Enzymes capable of performing dehalogenating reactions have attracted tremendous contemporary attention due to their potential application in the bioremediation of anthropogenic polyhalogenated persistent organic pollutants. Nature, in particular the marine environment, is also a prolific source of polyhalogenated organic natural products. The study of the biosynthesis of these natural products has furnished a diverse array of halogenation biocatalysts, but thus far no examples of dehalogenating enzymes have been reported from a secondary metabolic pathway. Here we show that the penultimate step in the biosynthesis of the highly brominated marine bacterial product pentabromopseudilin is catalyzed by an unusual debrominase Bmp8 that utilizes a redox thiol mechanism to remove the C-2 bromine atom of 2,3,4,5-tetrabromopyrrole to facilitate oxidative coupling to 2,4-dibromophenol. To the best of our knowledge, Bmp8 is first example of a dehalogenating enzyme from the established genetic and biochemical context of a natural product biosynthetic pathway.

  9. The antimalarial drug quinine interferes with serotonin biosynthesis and action.

    Science.gov (United States)

    Islahudin, Farida; Tindall, Sarah M; Mellor, Ian R; Swift, Karen; Christensen, Hans E M; Fone, Kevin C F; Pleass, Richard J; Ting, Kang-Nee; Avery, Simon V

    2014-01-01

    The major antimalarial drug quinine perturbs uptake of the essential amino acid tryptophan, and patients with low plasma tryptophan are predisposed to adverse quinine reactions; symptoms of which are similar to indications of tryptophan depletion. As tryptophan is a precursor of the neurotransmitter serotonin (5-HT), here we test the hypothesis that quinine disrupts serotonin function. Quinine inhibited serotonin-induced proliferation of yeast as well as human (SHSY5Y) cells. One possible cause of this effect is through inhibition of 5-HT receptor activation by quinine, as we observed here. Furthermore, cells exhibited marked decreases in serotonin production during incubation with quinine. By assaying activity and kinetics of the rate-limiting enzyme for serotonin biosynthesis, tryptophan hydroxylase (TPH2), we showed that quinine competitively inhibits TPH2 in the presence of the substrate tryptophan. The study shows that quinine disrupts both serotonin biosynthesis and function, giving important new insight to the action of quinine on mammalian cells.

  10. In-situ glyoxalization during biosynthesis of bacterial cellulose.

    Science.gov (United States)

    Castro, Cristina; Cordeiro, Nereida; Faria, Marisa; Zuluaga, Robin; Putaux, Jean-Luc; Filpponen, Ilari; Velez, Lina; Rojas, Orlando J; Gañán, Piedad

    2015-08-01

    A novel method to synthesize highly crosslinked bacterial cellulose (BC) is reported. The glyoxalization is started in-situ, in the culture medium during biosynthesis of cellulose by Gluconacetobacter medellensis bacteria. Strong crosslinked networks were formed in the contact areas between extruded cellulose ribbons by reaction with the glyoxal precursors. The crystalline structure of cellulose was preserved while the acidic component of the surface energy was reduced. As a consequence, its predominant acidic character and the relative contribution of the dispersive component increased, endowing the BC network with a higher hydrophobicity. This route for in-situ crosslinking is expected to facilitate other modifications upon biosynthesis of cellulose ribbons by microorganisms and to engineer the strength and surface energy of their networks.

  11. [Gibberellins--structure, biosynthesis and deactivation in plants].

    Science.gov (United States)

    Marciniak, Katarzyna; Kesy, Jacek; Tretyn, Andrzej; Kopcewicz, Jan

    2012-01-01

    Gibberellins (GA), as one of the most important phytohormones, control different aspect of plant growth and development such as seed germination, stem elongation and floral induction. Although identified more than a hundred and thirty GA, only a small number of them are biological active. Many non-bioactive GA are present in plant tissues as precursors or deactivated metabolites. Biochemical and genetic approaches have led to the recognition most of the genes that encode GA biosynthesis and deactivation enzymes, and conducted investigation has helped us to better understand GA functions in plants. Many enzymes involved in GA metabolism are multifunctional and therefore fewer enzymes than might be expected are required to created the various gibberellins structures. In this review, we summarized current knowledge on the GA biosynthesis and deactivation pathways in plants and showed precise characteristic of genes and encoding protein which are involved in gibberellins metabolism.

  12. Endoplasmic Reticulum Stress and Insulin Biosynthesis: A Review

    Directory of Open Access Journals (Sweden)

    Mi-Kyung Kim

    2012-01-01

    Full Text Available Insulin resistance and pancreatic beta cell dysfunction are major contributors to the pathogenesis of diabetes. Various conditions play a role in the pathogenesis of pancreatic beta cell dysfunction and are correlated with endoplasmic reticulum (ER stress. Pancreatic beta cells are susceptible to ER stress. Many studies have shown that increased ER stress induces pancreatic beta cell dysfunction and diabetes mellitus using genetic models of ER stress and by various stimuli. There are many reports indicating that ER stress plays an important role in the impairment of insulin biosynthesis, suggesting that reduction of ER stress could be a therapeutic target for diabetes. In this paper, we reviewed the relationship between ER stress and diabetes and how ER stress controls insulin biosynthesis.

  13. Endoplasmic reticulum stress and insulin biosynthesis: a review.

    Science.gov (United States)

    Kim, Mi-Kyung; Kim, Hye-Soon; Lee, In-Kyu; Park, Keun-Gyu

    2012-01-01

    Insulin resistance and pancreatic beta cell dysfunction are major contributors to the pathogenesis of diabetes. Various conditions play a role in the pathogenesis of pancreatic beta cell dysfunction and are correlated with endoplasmic reticulum (ER) stress. Pancreatic beta cells are susceptible to ER stress. Many studies have shown that increased ER stress induces pancreatic beta cell dysfunction and diabetes mellitus using genetic models of ER stress and by various stimuli. There are many reports indicating that ER stress plays an important role in the impairment of insulin biosynthesis, suggesting that reduction of ER stress could be a therapeutic target for diabetes. In this paper, we reviewed the relationship between ER stress and diabetes and how ER stress controls insulin biosynthesis.

  14. Biosynthesis and Genetic Regulation of Proanthocyanidins in Plants

    Directory of Open Access Journals (Sweden)

    Chang-Qing Duan

    2008-10-01

    Full Text Available Proanthocyanidins (PAs, also known as condensed tannins, are a group of polyphenolic secondary metabolites synthesized in plants as oligomers or polymers of flavan-3-ol units via the flavonoid pathway. Due to their structural complexity and varied composition, only in the recent years has the study on the biosynthesis and regulation of PAs in plants taken off, although some details of the synthetic mechanism remain unclear. This paper aims to summarize the status of research on the structures of PAs in plants, the genes encoding key enzymes of biosynthetic pathway, the transport factors, the transcriptional regulation of PA biosynthesis and the genetic manipulation of PAs. The problems of this field were also discussed, including the nature of the final “enzyme” which catalyzes the polymerization reaction of PAs and the possible mechanism of how the elementary units of flavanols are assembled in vivo.

  15. A protein interaction map of the kalimantacin biosynthesis assembly line

    Directory of Open Access Journals (Sweden)

    Birgit Uytterhoeven

    2016-11-01

    Full Text Available The antimicrobial secondary metabolite kalimantacin is produced by a hybrid polyketide/ non-ribosomal peptide system in Pseudomonas fluorescens BCCM_ID9359. In this study, the kalimantacin biosynthesis gene cluster is analyzed by yeast two-hybrid analysis, creating a protein-protein interaction map of the entire assembly line. In total, 28 potential interactions were identified, of which 13 could be confirmed further. These interactions include the dimerization of ketosynthase domains, a link between assembly line modules 9 and 10, and a specific interaction between the trans-acting enoyl reductase BatK and the carrier proteins of modules 8 and 10. These interactions reveal fundamental insight into the biosynthesis of secondary metabolites.This study is the first to reveal interactions in a complete biosynthetic pathway. Similar future studies could build a strong basis for engineering strategies in such clusters.

  16. Improving penicillin biosynthesis in Penicillium chrysogenum by glyoxalase overproduction.

    Science.gov (United States)

    Scheckhuber, Christian Q; Veenhuis, Marten; van der Klei, Ida J

    2013-07-01

    Genetic engineering of fungal cell factories mainly focuses on manipulating enzymes of the product pathway or primary metabolism. However, despite the use of strong promoters or strains containing the genes of interest in multiple copies, the desired strongly enhanced enzyme levels are often not obtained. Here we present a novel strategy to improve penicillin biosynthesis by Penicillium chrysogenum by reducing reactive and toxic metabolic by-products, 2-oxoaldehydes. This was achieved by overexpressing the genes encoding glyoxalase I and II, which resulted in a 10% increase in penicillin titers relative to the control strain. The protein levels of two key enzymes of penicillin biosynthesis, isopenicillin N synthase and isopenicillin N acyltransferase, were increased in the glyoxalase transformants, whereas their transcript levels remained unaltered. These results suggest that directed intracellular reduction of 2-oxoaldehydes prolongs the functional lifetime of these enzymes.

  17. Compartmentalization in penicillin G biosynthesis by Penicillium chrysogenum PQ-96.

    Science.gov (United States)

    Kurzątkowski, Wiesław; Staniszewska, Monika; Bondaryk, Małgorzata; Gębska-Kuczerowska, Anita

    2014-01-01

    The arrangement of organelles in the sub-apical productive non-growing vacuolated hyphal cells of the high- and the low-penicillin-pro- ducing strains Penicillium chrysogenum was compared using transmission electron microscopy. In the productive cells of the high-yielding strain the endoplasmic reticulum and the polyribosomes with associated peroxisomes are frequently arranged at the periphery of the cytoplasm and around the vacuoles. At the high activity of penicillin G biosynthesis the immuno-label of the cytosolic isopenicillin N synthase is concentrated at the polyribosomes arranged in the peripheral cytoplasm and along the tonoplast as well as around the peroxisomes. On the basis of the obtained results the compartmentalization of the pathway of penicillin G biosymthesis is discussed. The obtained results support the phenylacetic acid detoxification hypothesis of penicillin G biosynthesis.

  18. Involvement of snapdragon benzaldehyde dehydrogenase in benzoic acid biosynthesis.

    Science.gov (United States)

    Long, Michael C; Nagegowda, Dinesh A; Kaminaga, Yasuhisa; Ho, Kwok Ki; Kish, Christine M; Schnepp, Jennifer; Sherman, Debra; Weiner, Henry; Rhodes, David; Dudareva, Natalia

    2009-07-01

    Benzoic acid (BA) is an important building block in a wide spectrum of compounds varying from primary metabolites to secondary products. Benzoic acid biosynthesis from L-phenylalanine requires shortening of the propyl side chain by two carbons, which can occur via a beta-oxidative pathway or a non-beta-oxidative pathway, with benzaldehyde as a key intermediate. The non-beta-oxidative route requires benzaldehyde dehydrogenase (BALDH) to convert benzaldehyde to BA. Using a functional genomic approach, we identified an Antirrhinum majus (snapdragon) BALDH, which exhibits 40% identity to bacterial BALDH. Transcript profiling, biochemical characterization of the purified recombinant protein, molecular homology modeling, in vivo stable isotope labeling, and transient expression in petunia flowers reveal that BALDH is capable of oxidizing benzaldehyde to BA in vivo. GFP localization and immunogold labeling studies show that this biochemical step occurs in the mitochondria, raising a question about the role of subcellular compartmentalization in BA biosynthesis.

  19. Biosynthesis of gold nanoparticles using streptomyces fulvissimus isolate

    Directory of Open Access Journals (Sweden)

    Meysam Soltani Nejad

    2015-04-01

    Full Text Available Objective(s: In recent years, the biosynthesis of gold nanoparticles has been the focus of interest because of their emerging application in a number of areas such as biomedicine. In the present study we report the extracellular biosynthesis of gold nanoparticles (AuNPs by using a positive bacterium named Streptomyces fulvissimus isolate U from rice fields of Guilan Province, Iran. Materials and Methods: From over 20 Streptomyces isolates collected, isolate U showed high AuNPs biosynthesis activity. To determine its taxonomical identity, its morphology was characterized by scanning electron microscope and partial molecular analysis performed by PCR. In this regard, 16S rDNA of isolate U was amplified using universal bacterial primers FD1 and RP2. The PCR products were purified and sequenced. Sequence analysis of 16S rDNA was then conducted using NCBI BLAST method. In biosynthesis of AuNPs by this bacterium, the biomass of bacterium exposed to the HAuCl4 solution. Results: The nanoparticles obtained were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM and Energy dispersive X-ray (EDX spectroscopy and X-ray diffraction spectroscopy (XRD analyses. Our results indicated that Streptomyces fulvissimus isolateU bio-synthesizes extracellular AuNPs in the range of 20-50 nm. Conclusions: This technique of green synthesis of AuNPs by a microbial source may become a promising method because of its environmental safety. Its optimization may make it a potential procedure for industrial production of gold nanoparticles.

  20. Mitochondrial lipid transport and biosynthesis: A complex balance

    Science.gov (United States)

    2016-01-01

    Little is known about how mitochondrial lipids reach inner membrane–localized metabolic enzymes for phosphatidylethanolamine synthesis. Aaltonen et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201602007) and Miyata et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601082) now report roles for two mitochondrial complexes, Ups2–Mdm35 and mitochondrial contact site and cristae organizing system, in the biosynthesis and transport of mitochondrial lipids. PMID:27354376

  1. ENDOCANNABINOIDS AND EICOSAMOIDS: BIOSYNTHESIS AND INTERACTIONS WITH IMMUNE RESPONSE

    Directory of Open Access Journals (Sweden)

    Yu. K. Karaman

    2013-01-01

    Full Text Available The review is dedicated to modern concepts of arachidonic acid metabolites, i.e., endocannabinoids and eicosanoids, their biosynthetic pathways, cross-talk mechanisms and participation in immune response. New information from literature and own results include data concerning overlapping enzymatic pathways controlling biosynthesis of endocannabinoids and eicosanoids. Impact of synthetic cannabinoid receptor ligands upon production rates of proinflammatory cytokines and eicosanoids is discussed, as like as relationships among immune system reactivity and expression levels of cannabinoid receptors.

  2. Monomethylarsonous acid inhibited endogenous cholesterol biosynthesis in human skin fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Lei [Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521-0403 (United States); Xiao, Yongsheng [Department of Chemistry, University of California, Riverside, CA 92521-0403 (United States); Wang, Yinsheng, E-mail: yinsheng.wang@ucr.edu [Environmental Toxicology Graduate Program, University of California, Riverside, CA 92521-0403 (United States); Department of Chemistry, University of California, Riverside, CA 92521-0403 (United States)

    2014-05-15

    Human exposure to arsenic in drinking water is a widespread public health concern, and such exposure is known to be associated with many human diseases. The detailed molecular mechanisms about how arsenic species contribute to the adverse human health effects, however, remain incompletely understood. Monomethylarsonous acid [MMA(III)] is a highly toxic and stable metabolite of inorganic arsenic. To exploit the mechanisms through which MMA(III) exerts its cytotoxic effect, we adopted a quantitative proteomic approach, by coupling stable isotope labeling by amino acids in cell culture (SILAC) with LC-MS/MS analysis, to examine the variation in the entire proteome of GM00637 human skin fibroblasts following acute MMA(III) exposure. Among the ∼ 6500 unique proteins quantified, ∼ 300 displayed significant changes in expression after exposure with 2 μM MMA(III) for 24 h. Subsequent analysis revealed the perturbation of de novo cholesterol biosynthesis, selenoprotein synthesis and Nrf2 pathways evoked by MMA(III) exposure. Particularly, MMA(III) treatment resulted in considerable down-regulation of several enzymes involved in cholesterol biosynthesis. In addition, real-time PCR analysis showed reduced mRNA levels of select genes in this pathway. Furthermore, MMA(III) exposure contributed to a distinct decline in cellular cholesterol content and significant growth inhibition of multiple cell lines, both of which could be restored by supplementation of cholesterol to the culture media. Collectively, the present study demonstrated that the cytotoxicity of MMA(III) may arise, at least in part, from the down-regulation of cholesterol biosynthesis enzymes and the resultant decrease of cellular cholesterol content. - Highlights: • MMA(III)-induced perturbation of the entire proteome of GM00637 cells is studied. • Quantitative proteomic approach revealed alterations of multiple cellular pathways. • MMA(III) inhibits de novo cholesterol biosynthesis. • MMA

  3. Regulation of neurosteroid biosynthesis by neurotransmitters and neuropeptides

    Directory of Open Access Journals (Sweden)

    Jean-Luc eDo-Rego

    2012-01-01

    Full Text Available The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out to visualize the neurotransmitter- or neuropeptide-containing fibers contacting steroid-synthesizing neurons as well as the neurotransmitter, peptide hormones or neuropeptide receptors expressed in these neurons. Biochemical experiments have been conducted to investigate the effects of neurotransmitters, peptide hormones or neuropeptides on neurosteroid biosynthesis, and to characterize the type of receptors involved. Thus, it has been found that glutamate, acting through kainate and/or AMPA receptors, rapidly inactivates P450arom, and that melatonin produced by the pineal gland and eye inhibits the biosynthesis of 7-hydroxypregnenolone (7-OH-5P, while prolactin produced by the adenohypophysis enhances the formation of 7-OH-5P. It has also been demonstrated that the biosynthesis of neurosteroids is inhibited by GABA, acting through GABAA receptors, and neuropeptide Y, acting through Y1 receptors. In contrast, it has been shown that the octadecaneuropetide ODN, acting through central-type benzodiazepine receptors, the triakontatetraneuropeptide TTN, acting though peripheral-type benzodiazepine receptors, and vasotocine, acting through V1a-like receptors, stimulate the production of neurosteroids. Since neurosteroids are implicated in the control of various neurophysiological and behavioral processes, these data suggest that some of the neurophysiological effects exerted by neurotransmitters and neuropeptides may be mediated via the regulation

  4. Novel Artificial Natural Products Against Breast Cancer Through Combinatorial Biosynthesis

    Science.gov (United States)

    2002-07-01

    The cloned genes should help to elucidate the molecular basis for indolocarbazole biosynthesis and set the stage for generation of novel... Biologia Funcional e Instituto Universitario de Oncologia del Principado de Asturias (I. U.O.P.A.), Universidad de Oviedo, 33006 Oviedo, Spain, and...Cundliffe, E. Microbiology 2000, 146, (48) Sanmbrook, J.; Fritsch, E. F.; Maniatis, T. Molecular Cloning. A Laboratory 139-146. Manual; Cold Spring

  5. A Comparison between Chemical Synthesis Magnetite Nanoparticles and Biosynthesis Magnetite

    OpenAIRE

    2014-01-01

    The preparation of Fe3O4 from ferrous salt by air in alkaline aqueous solution at various temperatures was proposed. The synthetic magnetites have different particle size distributions. We studied the properties of the magnetite prepared by chemical methods compared with magnetotactic bacterial nanoparticles. The results show that crystallite size, morphology, and particle size distribution of chemically prepared magnetite at 293 K are similar to biosynthesis of magnetite. The new preparation...

  6. Fluorometabolite biosynthesis and the fluorinase from Streptomyces cattleya.

    Science.gov (United States)

    Deng, Hai; O'Hagan, David; Schaffrath, Christoph

    2004-12-01

    This review outlines the recent developments in uncovering the enzymes and intermediates involved in fluorometabolite biosyntheses in the bacterium Streptomyces cattleya. A particular emphasis is placed on the purification and characterisation of the fluorinase, the C-F bond forming enzyme which initiates the biosynthesis. Nature has hardly developed a biochemistry around fluorine, yet fluorinated organics are important commercial entities, therefore a biotransformation from inorganic to organic fluorine is novel and of contemporary interest.

  7. Evolution of alkaloid biosynthesis in the genus Narcissus.

    Science.gov (United States)

    Berkov, Strahil; Martínez-Francés, Vanessa; Bastida, Jaume; Codina, Carles; Ríos, Segundo

    2014-03-01

    In an attempt to reveal the relationships between alkaloid biosynthesis and phylogeny, we investigated by GC-MS the alkaloid patterns of 22 species and 3 hybrids (from 45 locations) from seven main sections of the genus Narcissus (Amaryllidaceae). The results indicate that the first alkaloids to evolve in the genus Narcissus were of the lycorine- and homolycorine-type. The alkaloid pattern of the Nevadensis section supports its recent separation from the Pseudonarcissus section. The plants of Narcissus pallidulus (Ganymedes section) show a predominance of Sceletium-type compounds, which are quite rare in the Amaryllidaceae family. Two successful evolutionary strategies involving alkaloid biosynthesis and leading to an expansion in taxa and occupied area were determined. Firstly, a diversification of alkaloid patterns and a high alkaloid concentration in the organs of the large Narcissus species (in the Pseudonarcissus section) resulted in an improved chemical defence in diverse habitats. Secondly, both plant size and alkaloid biosynthesis were reduced (in the Bulbocodium and Apodanthi sections) relegated to dry pastures and rocky places.

  8. Essential oil biosynthesis and regulation in the genus Cymbopogon.

    Science.gov (United States)

    Ganjewala, Deepak; Luthra, Rajesh

    2010-01-01

    Essential oils distilled from Cymbopogon species are of immense commercial value as flavors and fragrances in the perfumery, cosmetics, soaps, and detergents and in pharmaceutical industries. Two major constituents of the essential oil, geraniol and citral, due to their specific rose and lemon like aromas are widely used as flavors, fragrances and cosmetics. Citral is also used for the synthesis of vitamin A and ionones (for example, beta-ionone, methyl ionone). Moreover, Cymbopogon essential oils and constituents possess many useful biological activities including cytotoxic, anti-inflammatory and antioxidant. Despite the immense commercial and biological significance of the Cymbopogon essential oils, little is known about their biosynthesis and regulatory mechanisms. So far it is known that essential oils are biosynthesized via the classical acetate-MVA route and existence of a newly discovered MEP pathway in Cymbopogon remains as a topic for investigation. The aim of the present review is to discuss the biosynthesis and regulation of essential oils in the genus Cymbopogon with given emphasis to two elite members, lemongrass (C. flexuosus Nees ex Steud) and palmarosa (C. martinii Roxb.). This article highlights the work done so far towards understanding of essential oil biosynthesis and regulation in the genus Cymbopogon. Also, based on our experiences with Cymbopogon species, we would like to propose C. flexuosus as a model system for the study of essential oil metabolism beyond the much studied plant family Lamiaceae.

  9. Reduction of PCN biosynthesis by NO in Pseudomonas aeruginosa.

    Science.gov (United States)

    Gao, Lei; Zhang, Yuying; Wang, Yan; Qiao, Xinhua; Zi, Jing; Chen, Chang; Wan, Yi

    2016-08-01

    Pyocyanin (PCN), a virulence factor synthesized by Pseudomonas aeruginosa, plays an important role during clinical infections. There is no study of the effect of nitric oxide (NO) on PCN biosynthesis. Here, the effect of NO on PCN levels in Pseudomonas aeruginosa strain PAO1, a common reference strain, was tested. The results showed that the NO donor sodium nitroprusside (SNP) can significantly reduce PCN levels (82.5% reduction at 60μM SNP). Furthermore, the effect of endogenous NO on PCN was tested by constructing PAO1 nor (NO reductase gene) knockout mutants. Compared to the wild-type strain, the Δnor strain had a lower PCN (86% reduction in Δnor). To examine whether the results were universal with other P. aeruginosa strains, we collected 4 clinical strains from a hospital, tested their PCN levels after SNP treatment, and obtained similar results, i.e., PCN biosynthesis was inhibited by NO. These results suggest that NO treatment may be a new strategy to inhibit PCN biosynthesis and could provide novel insights into eliminating P. aeruginosa virulence as a clinical goal.

  10. Reduction of PCN biosynthesis by NO in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2016-08-01

    Full Text Available Pyocyanin (PCN, a virulence factor synthesized by Pseudomonas aeruginosa, plays an important role during clinical infections. There is no study of the effect of nitric oxide (NO on PCN biosynthesis. Here, the effect of NO on PCN levels in Pseudomonas aeruginosa strain PAO1, a common reference strain, was tested. The results showed that the NO donor sodium nitroprusside (SNP can significantly reduce PCN levels (82.5% reduction at 60 μM SNP. Furthermore, the effect of endogenous NO on PCN was tested by constructing PAO1 nor (NO reductase gene knockout mutants. Compared to the wild-type strain, the Δnor strain had a lower PCN (86% reduction in Δnor. To examine whether the results were universal with other P. aeruginosa strains, we collected 4 clinical strains from a hospital, tested their PCN levels after SNP treatment, and obtained similar results, i.e., PCN biosynthesis was inhibited by NO. These results suggest that NO treatment may be a new strategy to inhibit PCN biosynthesis and could provide novel insights into eliminating P. aeruginosa virulence as a clinical goal.

  11. Evaluation of Biosynthetic Pathway and Engineered Biosynthesis of Alkaloids

    Directory of Open Access Journals (Sweden)

    Shinji Kishimoto

    2016-08-01

    Full Text Available Varieties of alkaloids are known to be produced by various organisms, including bacteria, fungi and plants, as secondary metabolites that exhibit useful bioactivities. However, understanding of how those metabolites are biosynthesized still remains limited, because most of these compounds are isolated from plants and at a trace level of production. In this review, we focus on recent efforts in identifying the genes responsible for the biosynthesis of those nitrogen-containing natural products and elucidating the mechanisms involved in the biosynthetic processes. The alkaloids discussed in this review are ditryptophenaline (dimeric diketopiperazine alkaloid, saframycin (tetrahydroisoquinoline alkaloid, strictosidine (monoterpene indole alkaloid, ergotamine (ergot alkaloid and opiates (benzylisoquinoline and morphinan alkaloid. This review also discusses the engineered biosynthesis of these compounds, primarily through heterologous reconstitution of target biosynthetic pathways in suitable hosts, such as Escherichia coli, Saccharomyces cerevisiae and Aspergillus nidulans. Those heterologous biosynthetic systems can be used to confirm the functions of the isolated genes, economically scale up the production of the alkaloids for commercial distributions and engineer the biosynthetic pathways to produce valuable analogs of the alkaloids. In particular, extensive involvement of oxidation reactions catalyzed by oxidoreductases, such as cytochrome P450s, during the secondary metabolite biosynthesis is discussed in details.

  12. Controllable Biosynthesis and Properties of Gold Nanoplates Using Yeast Extract

    Institute of Scientific and Technical Information of China (English)

    Zhi Yang; Yasha Yi; Zhaohui Li; Xuxing Lu; Fengjiao He; Xingzhong Zhu; Yujie Ma; Rong He; Feng Gao; Weihai Ni

    2017-01-01

    Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source and difficulties of controllable formation of morphology and size. Herein, one-pot biosynthesis of gold nanoplates is proposed, in which cheap yeast was extracted as a green precursor. The morphologies and sizes of the gold nanostructures can be controlled via varying the pH value of the biomedium. In acid condition, gold nanoplates with side length from 1300 ± 200 to 300 ± 100 nm and height from 18 to 15 nm were obtained by increasing the pH value. Whereas, in neutral or basic condition, only gold nanoflowers and nanoparticles were obtained. It was determined that organic molecules, such as succinic acid, lactic acid, malic acid, and glutathione, which are generated in metabolism process, played important role in the reduction of gold ions. Besides, it was found that the gold nanoplates exhibited plasmonic property with prominent dipole infrared resonance in near-infrared region, indicating their potential in surface plasmon-enhanced applications, such as bioimaging and photothermal therapy.

  13. Effect of Methyl Jasmonic Acid on Baccatin Ⅲ Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jianfeng; GUO Zhigang

    2006-01-01

    As baccatin Ⅲ is an immediate diterpenoid precursor of taxol, the increase of baccatin Ⅲ is beneficial to the biosynthesis of taxol. Addition of methyl jasmonic acid (M J) enhances the activity of 10- deaceyle baccatin (DAB) Ⅲ acetyl transferase which catalyzes the bioconversion from 10-DAB Ⅲ to beccatin Ⅲ. In this paper, the baccatin Ⅲ content was increased by 174% by the addition of 100 μmol/L MJ in suspension cultures of Taxus cuspidate. Induction by MJ also increased the expression of a 49.0-kDa protein. This paper describes the cell free acetylation of 10-DAB Ⅲ in crude extracts of enzyme from the suspension cultures of Taxus cuspidate. The reaction product was confirmed by high performance liquid chromatograph (HPLC). About 25.0% of the 10-DAB Ⅲ was acetylized into baccatin Ⅲ on the 4th day with 100 μmol/L MJ.The 10-DAB Ⅲ acetyl transferase activity reached a peak on the 2nd day with 100 μmol/L M J, with 54.7% of the 10-DAB Ⅲ transformed into baccatin Ⅲ. The baccatin Ⅲ content increased with the increase of 10-DAB Ⅲ acetyl transferase activity, although the biosynthesis was delayed by more than 24 h. The remarkable induction of MJ on baccatin Ⅲ biosynthesis shows a promising way to increase the production of taxol.

  14. Histidine biosynthesis, its regulation and biotechnological application in Corynebacterium glutamicum.

    Science.gov (United States)

    Kulis-Horn, Robert K; Persicke, Marcus; Kalinowski, Jörn

    2014-01-01

    l-Histidine biosynthesis is an ancient metabolic pathway present in bacteria, archaea, lower eukaryotes, and plants. For decades l-histidine biosynthesis has been studied mainly in Escherichia coli and Salmonella typhimurium, revealing fundamental regulatory processes in bacteria. Furthermore, in the last 15 years this pathway has been also investigated intensively in the industrial amino acid-producing bacterium Corynebacterium glutamicum, revealing similarities to E. coli and S. typhimurium, as well as differences. This review summarizes the current knowledge of l-histidine biosynthesis in C. glutamicum. The genes involved and corresponding enzymes are described, in particular focusing on the imidazoleglycerol-phosphate synthase (HisFH) and the histidinol-phosphate phosphatase (HisN). The transcriptional organization of his genes in C. glutamicum is also reported, including the four histidine operons and their promoters. Knowledge of transcriptional regulation during stringent response and by histidine itself is summarized and a translational regulation mechanism is discussed, as well as clues about a histidine transport system. Finally, we discuss the potential of using this knowledge to create or improve C. glutamicum strains for the industrial l-histidine production.

  15. Expression of the carotenoid biosynthesis genes in Xanthophyllomyces dendrorhous.

    Science.gov (United States)

    Lodato, P; Alcaíno, J; Barahona, S; Niklitschek, M; Carmona, M; Wozniak, A; Baeza, M; Jiménez, A; Cifuentes, V

    2007-01-01

    In the yeast Xanthophyllomyces dendrorhous the genes idi, crtE, crtYB, crtl and ast are involved in the biosynthesis of astaxanthin from isopentenyl pyrophosphate. The carotenoid production and the kinetics of mRNA expression of structural genes controlling the carotenogenesis in a wild-type ATCC 24230 and in carotenoid overproducer deregulated atxS2 strains were studied. The biosynthesis of carotenoid was induced at the late exponential growth phase in both strains. However, the cellular carotenoid concentration was four times higher in atxS2 than in the wild-type strain in the exponential growth phase, suggesting that carotenogenesis was deregulated in atxS2 at the beginning of growth. In addition, the maximum expression of the carotenogenesis genes at the mRNA level was observed during the induction period of carotenoid biosynthesis in the wild-type strain. The mRNA level of the crtYB, crtl, ast genes and to a lesser extent the idi gene, decayed at the end of the exponential growth phase. The mRNA levels of the crtE gene remained high along the whole growth curve of the yeast. In the atxS2 strain the mRNA levels of crtE gene were about two times higher than the wild-type strain in the early phase of the growth cycle.

  16. Extra-gonadal sites of estrogen biosynthesis and function.

    Science.gov (United States)

    Barakat, Radwa; Oakley, Oliver; Kim, Heehyen; Jin, Jooyoung; Ko, CheMyong Jay

    2016-09-01

    Estrogens are the key hormones regulating the development and function of reproductive organs in all vertebrates. Recent evidence indicates that estrogens play important roles in the immune system, cancer development, and other critical biological processes related to human well-being. Obviously, the gonads (ovary and testis) are the primary sites of estrogen synthesis, but estrogens synthesized in extra- gonadal sites play an equally important role in controlling biological activities. Understanding non-gonadal sites of estrogen synthesis and function is crucial and will lead to therapeutic interventions targeting estrogen signaling in disease prevention and treatment. Developing a rationale targeting strategy remains challenging because knowledge of extra-gonadal biosynthesis of estrogens, and the mechanism by which estrogen activity is exerted, is very limited. In this review, we will summarize recent discoveries of extra-gonadal sites of estrogen biosynthesis and their local functions and discuss the significance of the most recent novel discovery of intestinal estrogen biosynthesis. [BMB Reports 2016; 49(9): 488-496].

  17. Disruption of Sphingolipid Biosynthesis Blocks Phagocytosis of Candida albicans.

    Directory of Open Access Journals (Sweden)

    Fikadu G Tafesse

    2015-10-01

    Full Text Available The ability of phagocytes to clear pathogens is an essential attribute of the innate immune response. The role of signaling lipid molecules such as phosphoinositides is well established, but the role of membrane sphingolipids in phagocytosis is largely unknown. Using a genetic approach and small molecule inhibitors, we show that phagocytosis of Candida albicans requires an intact sphingolipid biosynthetic pathway. Blockade of serine-palmitoyltransferase (SPT and ceramide synthase-enzymes involved in sphingolipid biosynthesis- by myriocin and fumonisin B1, respectively, impaired phagocytosis by phagocytes. We used CRISPR/Cas9-mediated genome editing to generate Sptlc2-deficient DC2.4 dendritic cells, which lack serine palmitoyl transferase activity. Sptlc2-/- DC2.4 cells exhibited a stark defect in phagocytosis, were unable to bind fungal particles and failed to form a normal phagocytic cup to engulf C. albicans. Supplementing the growth media with GM1, the major ganglioside present at the cell surface, restored phagocytic activity of Sptlc2-/- DC2.4 cells. While overall membrane trafficking and endocytic pathways remained functional, Sptlc2-/- DC2.4 cells express reduced levels of the pattern recognition receptors Dectin-1 and TLR2 at the cell surface. Consistent with the in vitro data, compromised sphingolipid biosynthesis in mice sensitizes the animal to C. albicans infection. Sphingolipid biosynthesis is therefore critical for phagocytosis and in vivo clearance of C. albicans.

  18. Molecular Dissection of Xylan Biosynthesis during Wood Formation in Poplar

    Institute of Scientific and Technical Information of China (English)

    Chanhui Lee; Quincy Teng; Ruiqin Zhong; Zheng-Hua Ye

    2011-01-01

    Xylan, being the second most abundant polysaccharide in dicot wood, is considered to be one of the factors contributing to wood biomass recalcitrance for biofuel production. To better utilize wood as biofuel feedstock, it is crucial to functionally characterize all the genes involved in xylan biosynthesis during wood formation. In this report, we inves-tigated roles of poplar families GT43 and GT8 glycosyltransferases in xylan biosynthesis during wood formation. There exist seven GT43 genes in the genome of poplar (Populus trichocarpa), five of which, namely PtrGT43A, PtrGT43B,PtrGT43C, PtrGT43D, and PtrGT43E, were shown to be highly expressed in the developing wood and their encoded proteins were localized in the Golgi. Comprehensive genetic complementation coupled with chemical analyses demonstrated that overexpression of PtrGT43A/B/E but not PtrGT43C/D was able to rescue the xylan defects conferred by the Arabidopsis irx9mutant, whereas overexpression of PtrGT43C/D but not PtrGT43A/B/E led to a complementation of the xyian defects in the Arabidopsis irx14 mutant. The essential roles of poplar GT43 members in xylan biosynthesis was further substantiated by RNAi down-regulation of GT43B in the hybrid poplar (Populus alba x tremula)leading to reductions in wall thickness and xylan content in wood, and an elevation in the abundance of the xylan reducing end sequence. Wood digestibility analysis revealed that cellulase digestion released more glucose from the wood of poplar GT43B RNAi lines than the control wood, indicating a decrease in wood biomass recalcitrance. Furthermore, RNAi down-regulation of another poplar wood-associated glycosyltransferase, PoGT8D, was shown to cause decreases in wall thickness and xylan content as well as in the abundance of the xylan reducing end sequence. Together, these findings demonstrate that the poplar GT43 mem-bers form two functionally non-redundant groups, namely PtrGT43A/B/E as functional orthologs of Arabidopsis IRX9 and Ptr

  19. Effect of low temperature on highly unsaturated fatty acid biosynthesis in activated sludge.

    Science.gov (United States)

    He, Su; Ding, Li-Li; Xu, Ke; Geng, Jin-Ju; Ren, Hong-Qiang

    2016-07-01

    Low temperature is a limiting factor for the microbial activity of activated sludge for sewage treatment plant in winter. Highly unsaturated fatty acid (UFA) biosynthesis, phospholipid fatty acid (PLFA) constituents and microbial structure in activated sludge at low temperature were investigated. Over 12 gigabases of metagenomic sequence data were generated with the Illumina HiSeq 2000 platform. The result showed 43.11% of phospholipid fatty acid (PLFA) in the activated sludge participated in UFA biosynthesis, and γ-Linolenic could be converted to Arachidonic acid at low temperature. The highly UFA biosynthesis in activated sludge was n-6 highly UFA biosynthesis, rather than n-3 highly UFA biosynthesis. The microbial community structures of activated sludge were analyzed by PLFA and high-throughput sequencing (HiSeq) simultaneously. Acidovorax, Pseudomonas, Flavobacterium and Polaromonas occupied higher percentage at 5°C, and genetic changes of highly UFA biosynthesis derived from microbial community structures change.

  20. Inhibition of lipid mediator biosynthesis in human inflammatory cells by BIRM 270.

    Science.gov (United States)

    Parks, T P; Hoffman, A F; Homon, C A; Graham, A G; Lazer, E S; Chilton, F H; Borgeat, P; Raible, D; Schulman, E; Bass, D A

    1995-01-01

    BIRM 270 was developed as a potent and enantioselective inhibitor of LTB4 biosynthesis by human neutrophils, and was also found to inhibit LTC4 production by human eosinophils and lung mast cells. BIRM 270 inhibited LTB4 synthesis in neutrophils by preventing arachidonate release from membrane phospholipids, and over the same concentration range, inhibited PAF biosynthesis. BIRM 270 did not directly inhibit acylhydrolases which have been implicated in eicosanoid and PAF biosynthesis, suggesting an indirect mode of action.

  1. Terpenoid biosynthesis in Euphorbia lathyris and Copaifera spp

    Energy Technology Data Exchange (ETDEWEB)

    Skrukrud, C.L.

    1987-07-01

    Biosynthesis of triterpenoids by isolated latex of Euphorbia lathyris was investigated. The rate of in vitro incorporation of mevalonic acid into triterpenoids was thirty times greater than acetate incorporation indicating that the rate-limiting step in the pathway occurs prior to mevalonate. Both HMG-CoA reductase (EC 1.1.1.34) and HMG-CoA lyase (EC 4.1.3.4) activities were detected in isolated latex. HMG-CoA reductase was localized to a membrane-bound fraction of a 5000g pellet of latex. The rate of conversion of HMG-CoA to mevalonate by this enzyme is comparable to the overall rate of acetate incorporation into the triterpenoids suggesting that this enzyme is rate-determining in the biosynthesis of triterpenoids in E. lathyris latex. HMG-CoA reductase of E. lathyris vegetative tissue was localized to the membrane-bound portion of a particulate fraction (18,000g), and was solubilized by treatment with 2% polyoxyethylene ether W-1. Differences in the optimal pH for activity of HMG-CoA reductase from the latex and vegetative tissue suggest that isozymes of the enzyme may be present in the two tissue types. Studies of the incorporation of various precursors into leaf discs and cuttings taken from Copaifera spp. show differences in the rate of incorporation into Copaifera sesquiterpenes suggesting that the site of sesquiterpene biosynthesis may differ in its accessibility to the different substrates and/or reflecting the metabolic controls on carbon allocation to the terpenes. Mevalonate incorporation by Copaifera langsdorfii cuttings into sesquiterpenes was a hundred-fold greater than either acetate or glucose incorporation, however, its incorporation into squalene and triterpenoids was also a hundred-fold greater than the incorporation into sesquiterpenes. 119 refs., 58 figs., 16 tabs.

  2. Biosynthesis of fluorinated secondary metabolites by Streptomyces cattleya.

    Science.gov (United States)

    Reid, K A; Hamilton, J T; Bowden, R D; O'Hagan, D; Dasaradhi, L; Amin, M R; Harper, D B

    1995-06-01

    The biosynthesis of organofluorine compounds by Streptomyces cattleya NRRL 8057 was examined using 19F NMR spectroscopy. The organism produced 1.2 mM fluoroacetate and 0.5 mM 4-fluorothreonine as secondary metabolites when cultured for 28 d on a chemically defined medium containing 2 mM fluoride. Cell suspensions from batch cultures harvested at the growth maximum of 4 d were not capable of fluoride uptake or fluorometabolite biosynthesis, but by 6 d had developed an efficient fluoride-uptake system and biosynthesized the two fluorometabolites in almost equal proportions. As the harvest age increased, the proportion of fluoroacetate to 4-fluorothreonine formed by cell suspensions rose progressively so that 16-d-old cells showed a ratio of 76:26 for the two compounds. Fluoride uptake and fluorometabolite production by cell suspensions were highly dependent on pH, with both processes showing a maximum rate at pH 6.0 but declining rapidly at higher pH values. This decrease was particularly marked in the case of fluoroacetate biosynthesis which was barely detectable at pH 7.5. Fluoroacetate and 4-fluorothreonine showed only low levels of interconversion by cell suspensions, suggesting that the carbon skeleton of neither was derived by metabolism of the other. The limited interconversion observed is explicable in terms of a small degree of biological defluorination occurring with each compound, followed by reincorporation of the resulting fluoride ion into the organic form by the active fluorinating system, a phenomenon also noted on incubation of cell suspensions with a number of other fluorinated biochemical intermediates.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. [Salidroside biosynthesis pathway: the initial reaction and glycosylation of tyrosol].

    Science.gov (United States)

    Ma, Lanqing; Liu, Chunmei; Yu, Hansong; Zhang, Jixing; Gao, Dongyao; Li, Yanfang; Wang, Younian

    2012-03-01

    Salidroside, the 8-O-beta-D-glucoside of tyrosol, is a novel adaptogenic drug extracted from the medicinal plant Rhodiola sachalinensis A. Bor. Due to the scarcity of R. sachalinensis and its low yield of salidroside, there is great interest in enhancing the production of salidroside by biotechnological process. Glucosylation of tyrosol is thought to be the final step in salidroside biosynthesis. In our related works, three UGT clones were isolated from the roots and the cultured cells. Our intention was to combine the catalytic specificity of these UGTs in vitro in order to change the level of salidroside in vivo by over-expression of the above UGTs. However, as the aglycone substrate of salidroside, the biosynthetic pathway of tyrosol and its regulation are less well understood. The results of related studies revealed that there are two different possibilities for the tyrosol biosynthetic pathway. One possibility is that tyrosol is produced from a p-coumaric acid precursor, which is derived mainly from phenylalanine. The second possibility is that the precursor of tyrosol might be tyramine, which is synthesized from tyrosine. Our previous work demonstrated that over-expression of the endogenous phenylalanine ammonia-lyase gene (PALrs1) and accumulation of p-coumaric acid did not facilitate tyrosol biosynthesis. In contrast, the data presented in our recent work provide in vitro and in vivo evidence that the tyrosine decarboxylase (RsTyrDC) is most likely to have an important function in the initial reaction of the salidroside biosynthesis pathway in R. Sachalinensis.

  4. Plant science. Biosynthesis, regulation, and domestication of bitterness in cucumber.

    Science.gov (United States)

    Shang, Yi; Ma, Yongshuo; Zhou, Yuan; Zhang, Huimin; Duan, Lixin; Chen, Huiming; Zeng, Jianguo; Zhou, Qian; Wang, Shenhao; Gu, Wenjia; Liu, Min; Ren, Jinwei; Gu, Xingfang; Zhang, Shengping; Wang, Ye; Yasukawa, Ken; Bouwmeester, Harro J; Qi, Xiaoquan; Zhang, Zhonghua; Lucas, William J; Huang, Sanwen

    2014-11-28

    Cucurbitacins are triterpenoids that confer a bitter taste in cucurbits such as cucumber, melon, watermelon, squash, and pumpkin. These compounds discourage most pests on the plant and have also been shown to have antitumor properties. With genomics and biochemistry, we identified nine cucumber genes in the pathway for biosynthesis of cucurbitacin C and elucidated four catalytic steps. We discovered transcription factors Bl (Bitter leaf) and Bt (Bitter fruit) that regulate this pathway in leaves and fruits, respectively. Traces in genomic signatures indicated that selection imposed on Bt during domestication led to derivation of nonbitter cucurbits from their bitter ancestors.

  5. Circadian clock feedback cycle through NAMPT-mediated NAD+ biosynthesis.

    Science.gov (United States)

    Ramsey, Kathryn Moynihan; Yoshino, Jun; Brace, Cynthia S; Abrassart, Dana; Kobayashi, Yumiko; Marcheva, Biliana; Hong, Hee-Kyung; Chong, Jason L; Buhr, Ethan D; Lee, Choogon; Takahashi, Joseph S; Imai, Shin-Ichiro; Bass, Joseph

    2009-05-01

    The circadian clock is encoded by a transcription-translation feedback loop that synchronizes behavior and metabolism with the light-dark cycle. Here we report that both the rate-limiting enzyme in mammalian nicotinamide adenine dinucleotide (NAD+) biosynthesis, nicotinamide phosphoribosyltransferase (NAMPT), and levels of NAD+ display circadian oscillations that are regulated by the core clock machinery in mice. Inhibition of NAMPT promotes oscillation of the clock gene Per2 by releasing CLOCK:BMAL1 from suppression by SIRT1. In turn, the circadian transcription factor CLOCK binds to and up-regulates Nampt, thus completing a feedback loop involving NAMPT/NAD+ and SIRT1/CLOCK:BMAL1.

  6. Biosynthesis of anti-HCV compounds using thermophilic microorganisms.

    Science.gov (United States)

    Rivero, Cintia W; De Benedetti, Eliana C; Sambeth, Jorge E; Lozano, Mario E; Trelles, Jorge A

    2012-10-01

    This work describes the application of thermophilic microorganisms for obtaining 6-halogenated purine nucleosides. Biosynthesis of 6-chloropurine-2'-deoxyriboside and 6-chloropurine riboside was achieved by Geobacillus stearothermophilus CECT 43 with a conversion of 90% and 68%, respectively. Furthermore, the selected microorganism was satisfactorily stabilized by immobilization in an agarose matrix. This biocatalyst can be reused at least 70 times without significant loss of activity, obtaining 379mg/L of 6-chloropurine-2'-deoxyriboside. The obtained compounds can be used as antiviral agents.

  7. [Regulation of plant height by gibberellins biosynthesis and signal transduction].

    Science.gov (United States)

    Wei, Lingzhu; Cheng, Jianhui; Li, Lin; Wu, Jiang

    2012-02-01

    Plant height is one of the most important agronomic traits that could affect both crop yield and quality. Among all the hormones, gibberellins are crucial to regulate plant height. Cloning and molecular mechanism research of the plant height genes associated gibberellins have extremely important value for the regulation of crop growth and agricultural production, and have been widely used in rice, wheat and other grain crops breeding. In order to promote utilization of gibberellins in fruit trees, flowers and other horticultural crops breeding, we reviewed the regulation of plant height by gibberellins biosynthesis and signal transduction at the molecular level in this paper.

  8. Recent advances in curdlan biosynthesis, biotechnological production, and applications.

    Science.gov (United States)

    Zhan, Xiao-Bei; Lin, Chi-Chung; Zhang, Hong-Tao

    2012-01-01

    Curdlan is a water-insoluble β-(1,3)-glucan produced by Agrobacterium species under nitrogen-limited condition. Its heat-induced gelling properties render curdlan to be very useful in the food industry initially. Recent advances in the understanding of the role curdlan plays in both innate and adaptive immunity lead to its growing applications in biomedicine. Our review focuses on the recent advances on curdlan biosynthesis and the improvements of curdlan fermentation production both from our laboratory and many others as well as the latest advances on the new applications of curdlan and its derivatives particularly in their immunological functions in biomedicine.

  9. Kinetic Modeling of Sunflower Grain Filling and Fatty Acid Biosynthesis

    Science.gov (United States)

    Durruty, Ignacio; Aguirrezábal, Luis A. N.; Echarte, María M.

    2016-01-01

    Grain growth and oil biosynthesis are complex processes that involve various enzymes placed in different sub-cellular compartments of the grain. In order to understand the mechanisms controlling grain weight and composition, we need mathematical models capable of simulating the dynamic behavior of the main components of the grain during the grain filling stage. In this paper, we present a non-structured mechanistic kinetic model developed for sunflower grains. The model was first calibrated for sunflower hybrid ACA855. The calibrated model was able to predict the theoretical amount of carbohydrate equivalents allocated to the grain, grain growth and the dynamics of the oil and non-oil fraction, while considering maintenance requirements and leaf senescence. Incorporating into the model the serial-parallel nature of fatty acid biosynthesis permitted a good representation of the kinetics of palmitic, stearic, oleic, and linoleic acids production. A sensitivity analysis showed that the relative influence of input parameters changed along grain development. Grain growth was mostly affected by the specific growth parameter (μ′) while fatty acid composition strongly depended on their own maximum specific rate parameters. The model was successfully applied to two additional hybrids (MG2 and DK3820). The proposed model can be the first building block toward the development of a more sophisticated model, capable of predicting the effects of environmental conditions on grain weight and composition, in a comprehensive and quantitative way. PMID:27242809

  10. Stereochemical diversity in lignan biosynthesis of Arctium lappa L.

    Science.gov (United States)

    Suzuki, Shiro; Umezawa, Toshiaki; Shimada, Mikio

    2002-06-01

    The stereochemistry of lignan biosynthesis in Arctium lappa L. is regulated organ-specifically. (+)-Secoisolariciresinol [81% enantiomeric excess (e.e.)] was isolated from A. lappa petioles. In sharp contrast, lignans whose predominant enantiomers have the opposite absolute configuration to that of (+)-secoisolariciresinol [i.e., (-)-matairesinol (>99% e.e.), (-)-arctigenin (>99% e.e.), and (-)-secoisolariciresinol (65% e.e.)] were isolated from seeds of the species. The stereochemical diversity of secoisolariciresinol was demonstrated with enzyme preparations from A. lappa petioles and seeds. Thus, a petiole enzyme preparation catalyzed the formation of (+)-pinoresinol (33% e.e.), (+)-lariciresinol (30% e.e.), and (+)-secoisolariciresinol (20% e.e.) from achiral coniferyl alcohol in the presence of NADPH and H202, whereas that from ripening seeds catalyzed the formation of (-)-pinoresinol (22% e.e.), (-)-lariciresinol (>99% e.e.), and (-)-secoisolariciresinol (38% e.e.) under the same conditions. In addition, the ripening seed enzyme preparation mediated the selective formation of the optically pure (>99% e.e.) (-)-enantiomer of matairesinol from racemic (+/-)-secoisolariciresinols in the presence of NADP. These results indicate that the stereochemical mechanism for lignan biosynthesis in A. lappa varies with organs, suggesting that multiple lignan-synthesizing isozymes are involved in the stereochemical control of lignan formation in A. lappa.

  11. Increased trehalose biosynthesis in Hartig net hyphae of ectomycorrhizas.

    Science.gov (United States)

    López, Mónica Fajardo; Männer, Philipp; Willmann, Anita; Hampp, Rüdiger; Nehls, Uwe

    2007-01-01

    To obtain photoassimilates in ectomycorrhizal symbiosis, the fungus has to create a strong sink, for example, by conversion of plant-derived hexoses into fungus-specific compounds. Trehalose is present in large quantities in Amanita muscaria and may thus constitute an important carbon sink. In Amanita muscaria-poplar (Populus tremula x tremuloides) ectomycorrhizas, the transcript abundances of genes encoding key enzymes of fungal trehalose biosynthesis, namely trehalose-6-phosphate synthase (TPS), trehalose-6-phosphate phosphatase (TPP) and trehalose phosphorylase (TP), were increased. When mycorrhizas were separated into mantle and Hartig net, TPS, TPP and TP expression was specifically enhanced in Hartig net hyphae. Compared with the extraradical mycelium, TPS and TPP expression was only slightly increased in the fungal sheath, while the increase in the expression of TP was more pronounced. TPS enzyme activity was also elevated in Hartig net hyphae, displaying a direct correlation between transcript abundance and turnover rate. In accordance with enhanced gene expression and TPS activity, trehalose content was 2.7 times higher in the Hartig net. The enhanced trehalose biosynthesis at the plant-fungus interface indicates that trehalose is a relevant carbohydrate sink in symbiosis. As sugar and nitrogen supply affected gene expression only slightly, the strongly increased expression of the investigated genes in mycorrhizas is presumably developmentally regulated.

  12. Biosynthesis of vanillin by the fungus Pycnoporus sanguineus MIP 95001

    Directory of Open Access Journals (Sweden)

    Sabrina Moro Villela Pacheco

    2013-09-01

    Full Text Available Vanillin (a substance popularly known as vanilla flavor is one of the most widely used compounds, mainly by food and pharmaceutical industries. This substance can be obtained from the orchid Vanilla planifolia, but this is costly and time consuming. Thus, other methods for obtaining vanillin have been studied. Within this context, the aim of this work was to study the biosynthesis of vanillin by three strains of Pycnoporus sanguineus through the use of vanillic acid as a precursor. The strains were cultured in Petri dishes with a potato dextrose agar medium. Fragments of the media with the fungus were then inoculated in Erlenmeyer flasks with a liquid medium of potato broth and 0.3 g.L-1 of vanillic acid. The flasks remained in a shaker for eight days at 28°C and 120 rpm. Samples were withdrawn once a day (0.8 mL.day-1 for analysis of vanillin, glucose, total phenols, total proteins, and laccase. The results showed that only the MIP 95001 strain promoted the biosynthesis of vanillin. The highest concentration of vanillin was detected on the fourth day of cultivation (8.75 mg.dL-1. The results illustrate the ability to biosynthesize vanillin using Pycnoporus sanguineus (MIP 95001, which suggests a possible route for the biotechnological production of this flavor.

  13. Evolution of proline biosynthesis: enzymology, bioinformatics, genetics, and transcriptional regulation.

    Science.gov (United States)

    Fichman, Yosef; Gerdes, Svetlana Y; Kovács, Hajnalka; Szabados, László; Zilberstein, Aviah; Csonka, Laszlo N

    2015-11-01

    Proline is not only an essential component of proteins but it also has important roles in adaptation to osmotic and dehydration stresses, redox control, and apoptosis. Here, we review pathways of proline biosynthesis in the three domains of life. Pathway reconstruction from genome data for hundreds of eubacterial and dozens of archaeal and eukaryotic organisms revealed evolutionary conservation and variations of this pathway across different taxa. In the most prevalent pathway of proline synthesis, glutamate is phosphorylated to γ-glutamyl phosphate by γ-glutamyl kinase, reduced to γ-glutamyl semialdehyde by γ-glutamyl phosphate reductase, cyclized spontaneously to Δ(1)-pyrroline-5-carboxylate and reduced to proline by Δ(1)-pyrroline-5-carboxylate reductase. In higher plants and animals the first two steps are catalysed by a bi-functional Δ(1) -pyrroline-5-carboxylate synthase. Alternative pathways of proline formation use the initial steps of the arginine biosynthetic pathway to ornithine, which can be converted to Δ(1)-pyrroline-5-carboxylate by ornithine aminotransferase and then reduced to proline or converted directly to proline by ornithine cyclodeaminase. In some organisms, the latter pathways contribute to or could be fully responsible for the synthesis of proline. The conservation of proline biosynthetic enzymes and significance of specific residues for catalytic activity and allosteric regulation are analysed on the basis of protein structural data, multiple sequence alignments, and mutant studies, providing novel insights into proline biosynthesis in organisms. We also discuss the transcriptional control of the proline biosynthetic genes in bacteria and plants.

  14. [Biosynthesis and endocrine regulation of sex pheromones in moth].

    Science.gov (United States)

    Wang, Bo; Lin, Xin-da; Du, Yong-jun

    2015-10-01

    The crucial importance of sex pheromones in driving mating behaviors in moths has been well demonstrated in the process of sexual communication between individuals that produce and recognize species specific pheromones. Sex-pheromone molecules from different moth species are chemically characteristic, showing different terminal functional groups, various carbon chain lengths, different position and configuration of double bond system. This review summarized information on the biosynthetic pathways and enzymes involved in producing pheromone molecules in different moths. Then we listed the components and their ratios in the sex pheromones of 15 moth species belonging to different subfamilies in Noctuidae. We also discussed the various viewpoints regarding how sex pheromones with specific ratios are produced. In the discussion we attempted to classify the pheromone molecules based on their producers, characteristics of their functional groups and carbon chain lengths. In particular, composition and ratio variations of pheromones in closely related species or within a species were compared, and the possible molecular mechanisms for these variations and their evolutionary significance were discussed. Finally, we reviewed the endocrine regulation and signal transduction pathways, in which the pheromone biosynthesis activating neuropeptide (PBAN) is involved. Comparing the biosynthetic pathways of sex pheromones among different species, this article aimed to reveal the common principles in pheromone biosynthesis among moth species and the characteristic features associated with the evolutionary course of individual species. Subsequently, some future research directions were proposed.

  15. Gangliosides in the Nervous System: Biosynthesis and Degradation

    Science.gov (United States)

    Yu, Robert K.; Ariga, Toshio; Yanagisawa, Makoto; Zeng, Guichao

    Gangliosides, abundant in the nervous system, are known to play crucial modulatory roles in cellular recognition, interaction, adhesion, and signal transduction, particularly during early developmental stages. The expression of gangliosides in the nervous system is developmentally regulated and is closely related to the differentiation state of the cell. Ganglioside biosynthesis occurs in intracellular organelles, from which gangliosides are transported to the plasma membrane. During brain development, the ganglioside composition of the nervous system undergoes remarkable changes and is strictly regulated by the activities of glycosyltransferases, which can occur at different levels of control, including glycosyltransferase gene transcription and posttranslational modification. Genes for glycosyltransferase involved in ganglioside biosynthesis have been cloned and classified into families of glycosyltransferases based on their amino acid sequence similarities. The donor and acceptor substrate specificities are determined by enzymatic analysis of the glycosyltransferase gene products. Cell-type specific regulation of these genes has also been studied. Gangliosides are degraded by lysosomal exoglycosidases. The action of these enzymes occurs frequently in cooperation with activator proteins. Several human diseases are caused by defects of degradative enzymes, resulting in massive accumulation of certain glycolipids, including gangliosides in the lysosomal compartment and other organelles in the brain and visceral organs. Some of the representative lysosomal storage diseases (LSDs) caused by the accumulation of lipids in late endosomes and lysosomes will be discussed.

  16. Function and distribution of bilin biosynthesis enzymes in photosynthetic organisms.

    Science.gov (United States)

    Dammeyer, Thorben; Frankenberg-Dinkel, Nicole

    2008-10-01

    Bilins are open-chain tetrapyrrole molecules essential for light-harvesting and/or sensing in many photosynthetic organisms. While they serve as chromophores in phytochrome-mediated light-sensing in plants, they additionally function in light-harvesting in cyanobacteria, red algae and cryptomonads. Associated to phycobiliproteins a variety of bile pigments is responsible for the specific light-absorbance properties of the organisms enabling efficient photosynthesis under different light conditions. The initial step of bilin biosynthesis is the cleavage of heme by heme oxygenases (HO) to afford the first linear molecule biliverdin. This reaction is ubiquitously found also in non-photosynthetic organisms. Biliverdin is then further reduced by site specific reductases most of them belonging to the interesting family of ferredoxin-dependent bilin reductases (FDBRs)-a new family of radical oxidoreductases. In recent years much progress has been made in the field of heme oxygenases but even more in the widespread family of FDBRs, revealing novel biochemical FDBR activities, new crystal structures and new ecological aspects, including the discovery of bilin biosynthesis genes in wild marine phage populations. The aim of this review is to summarize and discuss the recent progress in this field and to highlight the new and remaining questions.

  17. Inhibition of arenavirus by A3, a pyrimidine biosynthesis inhibitor.

    Science.gov (United States)

    Ortiz-Riaño, Emilio; Ngo, Nhi; Devito, Stefanie; Eggink, Dirk; Munger, Joshua; Shaw, Megan L; de la Torre, Juan Carlos; Martínez-Sobrido, Luis

    2014-01-01

    Arenaviruses merit significant interest as important human pathogens, since several of them cause severe hemorrhagic fever disease that is associated with high morbidity and significant mortality. Currently, there are no FDA-licensed arenavirus vaccines available, and current antiarenaviral therapy is limited to an off-labeled use of the nucleoside analog ribavirin, which has limited prophylactic efficacy. The pyrimidine biosynthesis inhibitor A3, which was identified in a high-throughput screen for compounds that blocked influenza virus replication, exhibits a broad-spectrum antiviral activity against negative- and positive-sense RNA viruses, retroviruses, and DNA viruses. In this study, we evaluated the antiviral activity of A3 against representative Old World (lymphocytic choriomeningitis virus) and New World (Junin virus) arenaviruses in rodent, monkey, and human cell lines. We show that A3 is significantly more efficient than ribavirin in controlling arenavirus multiplication and that the A3 inhibitory effect is in part due to its ability to interfere with viral RNA replication and transcription. We document an additive antiarenavirus effect of A3 and ribavirin, supporting the potential combination therapy of ribavirin and pyrimidine biosynthesis inhibitors for the treatment of arenavirus infections.

  18. BODYGUARD is required for the biosynthesis of cutin in Arabidopsis.

    Science.gov (United States)

    Jakobson, Liina; Lindgren, Leif Ove; Verdier, Gaëtan; Laanemets, Kristiina; Brosché, Mikael; Beisson, Fred; Kollist, Hannes

    2016-07-01

    The cuticle plays a critical role in plant survival during extreme drought conditions. There are, however, surprisingly, many gaps in our understanding of cuticle biosynthesis. An Arabidopsis thaliana T-DNA mutant library was screened for mutants with enhanced transpiration using a simple condensation spot method. Five mutants, named cool breath (cb), were isolated. The cb5 mutant was found to be allelic to bodyguard (bdg), which is affected in an α/β-hydrolase fold protein important for cuticle structure. The analysis of cuticle components in cb5 (renamed as bdg-6) and another T-DNA mutant allele (bdg-7) revealed no impairment in wax synthesis, but a strong decrease in total cutin monomer load in young leaves and flowers. Root suberin content was also reduced. Overexpression of BDG increased total leaf cutin monomer content nearly four times by affecting preferentially C18 polyunsaturated ω-OH fatty acids and dicarboxylic acids. Whole-plant gas exchange analysis showed that bdg-6 had higher cuticular conductance and rate of transpiration; however, plant lines overexpressing BDG resembled the wild-type with regard to these characteristics. This study identifies BDG as an important component of the cutin biosynthesis machinery in Arabidopsis. We also show that, using BDG, cutin can be greatly modified without altering the cuticular water barrier properties and transpiration.

  19. Genetics of Dothistromin Biosynthesis in the Peanut Pathogen Passalora arachidicola

    Directory of Open Access Journals (Sweden)

    Rosie E. Bradshaw

    2010-11-01

    Full Text Available The peanut leaf spot pathogen Passalora arachidicola (Mycosphaerella arachidis is known to produce dothistromin, a mycotoxin related to aflatoxin. This is a feature shared with the pine needle pathogen Dothistroma septosporum (Mycosphaerella pini. Dothistromin biosynthesis in D. septosporum commences at an unusually early stage of growth in culture compared to most other fungal secondary metabolites, and the biosynthetic genes are arranged in fragmented groups, in contrast to aflatoxin gene clusters. Dothistromin biosynthetic genes were identified and studied in P. arachidicola to determine if the attributes described in D. septosporum are shared by another dothistromin-producing species within the Class Dothideomycetes. It was shown that dothistromin biosynthesis is very similar in the two species with regard to gene sequence and gene synteny. Functional complementation of D. septosporum mutants with P. arachidicola dothistromin genes was also possible. These similarities support a vertical mode of dothistromin gene transmission. P. arachidicola also produced dothistromin at an early growth stage in culture, suggesting that this type of regulation pattern may be relevant to the biological role of dothistromin.

  20. Specialised metabolites regulating antibiotic biosynthesis in Streptomyces spp.

    Science.gov (United States)

    Niu, Guoqing; Chater, Keith F; Tian, Yuqing; Zhang, Jihui; Tan, Huarong

    2016-07-01

    Streptomyces bacteria are the major source of antibiotics and other secondary metabolites. Various environmental and physiological conditions affect the onset and level of production of each antibiotic by influencing concentrations of the ligands for conserved global regulatory proteins. In addition, as reviewed here, well-known autoregulators such as γ-butyrolactones, themselves products of secondary metabolism, accumulate late in growth to concentrations allowing their effective interaction with cognate binding proteins, in a necessary prelude to antibiotic biosynthesis. Most autoregulator binding proteins target the conserved global regulatory gene adpA, and/or regulatory genes for 'cluster-situated regulators' (CSRs) linked to antibiotic biosynthetic gene clusters. It now appears that some CSRs bind intermediates and end products of antibiotic biosynthesis, with regulatory effects interwoven with those of autoregulators. These ligands can exert cross-pathway effects within producers of more than one antibiotic, and when excreted into the extracellular environment may have population-wide effects on production, and mediate interactions with neighbouring microorganisms in natural communities, influencing speciation. Greater understanding of these autoregulatory and cross-regulatory activities may aid the discovery of new signalling molecules and their use in activating cryptic antibiotic biosynthetic pathways.

  1. Biosynthesis of iridoids lacking C-10 and the chemotaxonomic implications of their distribution

    DEFF Research Database (Denmark)

    Frederiksen, Lotte Boe; Damtoft, Søren; Jensen, Søren Rosendal

    1999-01-01

    (=decapetaloside). Of these, only the first and the last were incorporated. Apparently, loss of C-10 in the biosynthesis of scabroside is analogous to that of stilbericoside and the sequence of events after formation of the 7,8-double bond appears in both cases to be the same as that found for the biosynthesis...

  2. Comparative Proteomic Analysis Reveals Proteins Putatively Involved in Toxin Biosynthesis in the Marine Dinoflagellate Alexandrium catenella

    Directory of Open Access Journals (Sweden)

    Da-Zhi Wang

    2013-01-01

    Full Text Available Alexandrium is a neurotoxin-producing dinoflagellate genus resulting in paralytic shellfish poisonings around the world. However, little is known about the toxin biosynthesis mechanism in Alexandrium. This study compared protein profiles of A. catenella collected at different toxin biosynthesis stages (non-toxin synthesis, initial toxin synthesis and toxin synthesizing coupled with the cell cycle, and identified differentially expressed proteins using 2-DE and MALDI-TOF-TOF mass spectrometry. The results showed that toxin biosynthesis of A. catenella occurred within a defined time frame in the G1 phase of the cell cycle. Proteomic analysis indicated that 102 protein spots altered significantly in abundance (P < 0.05, and 53 proteins were identified using database searching. These proteins were involved in a variety of biological processes, i.e., protein modification and biosynthesis, metabolism, cell division, oxidative stress, transport, signal transduction, and translation. Among them, nine proteins with known functions in paralytic shellfish toxin-producing cyanobacteria, i.e., methionine S-adenosyltransferase, chloroplast ferredoxin-NADP+ reductase, S-adenosylhomocysteinase, adenosylhomocysteinase, ornithine carbamoyltransferase, inorganic pyrophosphatase, sulfotransferase (similar to, alcohol dehydrogenase and arginine deiminase, varied significantly at different toxin biosynthesis stages and formed an interaction network, indicating that they might be involved in toxin biosynthesis in A. catenella. This study is the first step in the dissection of the behavior of the A. catenella proteome during different toxin biosynthesis stages and provides new insights into toxin biosynthesis in dinoflagellates.

  3. Inborn errors of metabolism in the biosynthesis and remodelling of phospholipids

    NARCIS (Netherlands)

    Wortmann, S.B.; Espeel, M.; Almeida, L.; Reimer, A.; Bosboom, D.G.; Roels, F.; Brouwer, A.P.M. de; Wevers, R.A.

    2015-01-01

    Since the proposal to define a separate subgroup of inborn errors of metabolism involved in the biosynthesis and remodelling of phospholipids, sphingolipids and long chain fatty acids in 2013, this group is rapidly expanding. This review focuses on the disorders involved in the biosynthesis of phosp

  4. Isolation and characterization of Pseudomonas aeruginosa mutants requiring salicylic acid for pyochelin biosynthesis.

    OpenAIRE

    Ankenbauer, R G; Cox, C D

    1988-01-01

    Pseudomonas aeruginosa mutants requiring salicylic acid for pyochelin biosynthesis were isolated after chemical mutagenesis by plating on a siderophore detection medium. Like the wild type, these mutants incorporated 7-[14C]salicylic acid into pyochelin, demonstrating that salicylic acid is an intermediate in the biosynthesis pathway of pyochelin.

  5. Purine biosynthesis in archaea: variations on a theme

    Directory of Open Access Journals (Sweden)

    Brown Anne M

    2011-12-01

    Full Text Available Abstract Background The ability to perform de novo biosynthesis of purines is present in organisms in all three domains of life, reflecting the essentiality of these molecules to life. Although the pathway is quite similar in eukaryotes and bacteria, the archaeal pathway is more variable. A careful manual curation of genes in this pathway demonstrates the value of manual curation in archaea, even in pathways that have been well-studied in other domains. Results We searched the Integrated Microbial Genome system (IMG for the 17 distinct genes involved in the 11 steps of de novo purine biosynthesis in 65 sequenced archaea, finding 738 predicted proteins with sequence similarity to known purine biosynthesis enzymes. Each sequence was manually inspected for the presence of active site residues and other residues known or suspected to be required for function. Many apparently purine-biosynthesizing archaea lack evidence for a single enzyme, either glycinamide ribonucleotide formyltransferase or inosine monophosphate cyclohydrolase, suggesting that there are at least two more gene variants in the purine biosynthetic pathway to discover. Variations in domain arrangement of formylglycinamidine ribonucleotide synthetase and substantial problems in aminoimidazole carboxamide ribonucleotide formyltransferase and inosine monophosphate cyclohydrolase assignments were also identified. Manual curation revealed some overly specific annotations in the IMG gene product name, with predicted proteins without essential active site residues assigned product names implying enzymatic activity (21 proteins, 2.8% of proteins inspected or Enzyme Commission (E. C. numbers (57 proteins, 7.7%. There were also 57 proteins (7.7% assigned overly generic names and 78 proteins (10.6% without E.C. numbers as part of the assigned name when a specific enzyme name and E. C. number were well-justified. Conclusions The patchy distribution of purine biosynthetic genes in archaea is

  6. On-Off Switches for Secondary Cell Wall Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Huan-Zhong Wang; Richard A.Dixon

    2012-01-01

    Secondary cell walls provide plants with rigidity and strength to support their body weight and ensure water and nutrient transport.They also provide textiles,timber,and potentially second-generation biofuels for human use.Genes responsible for synthesis of the different cell wall components,namely cellulose,hemicelluloses,and lignin,are coordinately expressed and under transcriptional regulation.In the past several years,cell wall-related NAC and MYB transcription factors have been intensively investigated in different species and shown to be master switches of secondary cell wall biosynthesis.Positive and negative regulators,which function upstream of NAC master switches,have also been identified in different plant tissues.Further elucidation of the regulatory mechanisms of cell wall synthesis will facilitate the engineering of plant feedstocks suitable for biofuel production.

  7. Chrysolina herbacea modulates terpenoid biosynthesis of Mentha aquatica L.

    Directory of Open Access Journals (Sweden)

    Simon Atsbaha Zebelo

    Full Text Available Interactions between herbivorous insects and plants storing terpenoids are poorly understood. This study describes the ability of Chrysolina herbacea to use volatiles emitted by undamaged Mentha aquatica plants as attractants and the plant's response to herbivory, which involves the production of deterrent molecules. Emitted plant volatiles were analyzed by GC-MS. The insect's response to plant volatiles was tested by Y-tube olfactometer bioassays. Total RNA was extracted from control plants, mechanically damaged leaves, and leaves damaged by herbivores. The terpenoid quantitative gene expressions (qPCR were then assayed. Upon herbivory, M. aquatica synthesizes and emits (+-menthofuran, which acts as a deterrent to C. herbacea. Herbivory was found to up-regulate the expression of genes involved in terpenoid biosynthesis. The increased emission of (+-menthofuran was correlated with the upregulation of (+-menthofuran synthase.

  8. Genetic Dissection of Tropodithietic Acid Biosynthesis by Marine Roseobacters

    DEFF Research Database (Denmark)

    Geng, Haifeng; Bruhn, Jesper Bartholin; Nielsen, Kristian Fog;

    2008-01-01

    formation is coincident with the production of an antibiotic and a yellow-brown pigment. In this report, we demonstrate that the antibiotic is a sulfur-containing compound, tropodithietic acid (TDA). Using random transposon insertion mutagenesis, 12 genes were identified as critical for TDA biosynthesis...... by the bacteria, and mutation in any one of these results in a loss of antibiotic activity (Tda(-)) and pigment production. Unexpectedly, six of the genes, referred to as tdaA-F, could not be found on the annotated TM1040 genome and were instead located on a previously unidentified plasmid (ca. 130 kb; pSTM3......) that exhibited a low frequency of spontaneous loss. Homologs of tdaA and tdaB from Silicibacter sp. strain TM1040 were identified by mutagenesis in another TDA-producing roseobacter, Phaeobacter sp. strain 27-4, which also possesses two large plasmids (ca. 60 and ca. 70 kb, respectively), and tda genes were...

  9. A mitochondrial pathway for biosynthesis of lipid mediators

    Science.gov (United States)

    Tyurina, Yulia Y.; Poloyac, Samuel M.; Tyurin, Vladimir A.; Kapralov, Alexander A.; Jiang, Jianfei; Anthonymuthu, Tamil Selvan; Kapralova, Valentina I.; Vikulina, Anna S.; Jung, Mi-Yeon; Epperly, Michael W.; Mohammadyani, Dariush; Klein-Seetharaman, Judith; Jackson, Travis C.; Kochanek, Patrick M.; Pitt, Bruce R.; Greenberger, Joel S.; Vladimirov, Yury A.; Bayır, Hülya; Kagan, Valerian E.

    2014-06-01

    The central role of mitochondria in metabolic pathways and in cell-death mechanisms requires sophisticated signalling systems. Essential in this signalling process is an array of lipid mediators derived from polyunsaturated fatty acids. However, the molecular machinery for the production of oxygenated polyunsaturated fatty acids is localized in the cytosol and their biosynthesis has not been identified in mitochondria. Here we report that a range of diversified polyunsaturated molecular species derived from a mitochondria-specific phospholipid, cardiolipin (CL), is oxidized by the intermembrane-space haemoprotein, cytochrome c. We show that a number of oxygenated CL species undergo phospholipase A2-catalysed hydrolysis and thus generate multiple oxygenated fatty acids, including well-known lipid mediators. This represents a new biosynthetic pathway for lipid mediators. We demonstrate that this pathway, which includes the oxidation of polyunsaturated CLs and accumulation of their hydrolysis products (oxygenated linoleic, arachidonic acids and monolysocardiolipins), is activated in vivo after acute tissue injury.

  10. Strategies for transgenic manipulation of monoterpene biosynthesis in plants.

    Science.gov (United States)

    Mahmoud, Soheil S; Croteau, Rodney B

    2002-08-01

    Monoterpenes, the C(10) isoprenoids, are a large family of natural products that are best known as constituents of the essential oils and defensive oleoresins of aromatic plants. In addition to ecological roles in pollinator attraction, allelopathy and plant defense, monoterpenes are used extensively in the food, cosmetic and pharmaceutical industries. The importance of these plant products has prompted the definition of many monoterpene biosynthetic pathways, the cloning of the relevant genes and the development of genetic transformation techniques for agronomically significant monoterpene-producing plants. Metabolic engineering of monoterpene biosynthesis in the model plant peppermint has resulted in yield increase and compositional improvement of the essential oil, and also provided strategies for manipulating flavor and fragrance production, and plant defense.

  11. Exopolysaccharides produced by Lactobacillus sp. - biosynthesis and applications.

    Science.gov (United States)

    Oleksy, Magdalena; Klewicka, Elżbieta

    2016-05-31

    Lactobacillus sp. synthesize exopolysaccharides (EPS), including both homo- and heteropolysaccharides, which play an important role in the production of fermented foods, and especially in the dairy industry, improving the gustatory and rheological properties of the finished products. These polymers are generated by starter cultures in situ in fermented foods, and so they are treated as natural thickening agents. As some Lactobacillus strains are generally recognized as safe (GRAS) and have been shown to exhibit probiotic activity, EPS from those bacteria can be used as functional food ingredients, conferring both health and economic benefits to the consumers. However, their industrial applications are hindered by the low yield of EPS from Lactobacillus and by the fact that the health-related properties of the bacteria have not been fully elucidated to date. This review focuses on the latest reports concerning the biosynthesis and properties of Lactobacillus exopolysaccharides.

  12. Streptomycetes biosynthesis processes in the presence of vegetable oils

    Directory of Open Access Journals (Sweden)

    I. V. Zhernosekova

    2012-06-01

    Full Text Available The rise of biosynthesis activity of the strain Streptomyces recifensis var. lyticus 2Р-15 induced by vegetable oil was established. When cultivating the streptomycetes in the mixed medium (glucose and sunflower oil the maximum biomass accumulation and staphylolytic enzymes’ activity of the strain 2P-15 increased by 19 and 20 % respectively in comparison with the streptomycetes grown in the medium of glucose and olive oil. The concentration of exogenic protein was also 9 times more for glucose and sunflower oil substrate. Monosubstrate of sunflower or olive oil didn’t increase the biosynthetic activity of the strain. However, the maximal indices were higher for sunflower oil than for olive one.

  13. Substances that disrupt thyroid hormone biosynthesis (in Romanian

    Directory of Open Access Journals (Sweden)

    Pap, Andreea

    2015-06-01

    Full Text Available Endocrine disrupters are natural or synthetic chemical substances that have the possibility to alter the endocrine functions leading to serious metabolic changes especially in newborns. The accumulation and persistence over long periods of time became a priority in terms of health and environment. The mechanism of action is represented by blocking, mimicking or modifying the effects of thyroid hormones. In this review, the main purpose was to determine what effects have the endocrine disruptors on the thyroid gland, especially on the thyroid hormone biosynthesis and setting the stage involved by it. We focused on the action of perchlorates, phthalates, BPC, PDPEs, soy, isoflavones, nitrates, thiocyanates, bisphenol A and triclorsan and came to the conclusion that their intervention can result in either hyperthyroidism or hypothyroidism.

  14. Tailoring lignin biosynthesis for efficient and sustainable biofuel production.

    Science.gov (United States)

    Liu, Chang-Jun; Cai, Yuanheng; Zhang, Xuebin; Gou, Mingyue; Yang, Huijun

    2014-12-01

    Increased global interest in a bio-based economy has reinvigorated the research on the cell wall structure and composition in plants. In particular, the study of plant lignification has become a central focus, with respect to its intractability and negative impact on the utilization of the cell wall biomass for producing biofuels and bio-based chemicals. Striking progress has been achieved in the last few years both on our fundamental understanding of lignin biosynthesis, deposition and assembly, and on the interplay of lignin synthesis with the plant growth and development. With the knowledge gleaned from basic studies, researchers are now able to invent and develop elegant biotechnological strategies to sophisticatedly manipulate the quantity and structure of lignin and thus to create economically viable bioenergy feedstocks. These concerted efforts open an avenue for the commercial production of cost-competitive biofuel to meet our energy needs.

  15. Biosynthesis of Carotenoids in Plants: Enzymes and Color.

    Science.gov (United States)

    Rosas-Saavedra, Carolina; Stange, Claudia

    2016-01-01

    Carotenoids are the most important biocolor isoprenoids responsible for yellow, orange and red colors found in nature. In plants, they are synthesized in plastids of photosynthetic and sink organs and are essential molecules for photosynthesis, photo-oxidative damage protection and phytohormone synthesis. Carotenoids also play important roles in human health and nutrition acting as vitamin A precursors and antioxidants. Biochemical and biophysical approaches in different plants models have provided significant advances in understanding the structural and functional roles of carotenoids in plants as well as the key points of regulation in their biosynthesis. To date, different plant models have been used to characterize the key genes and their regulation, which has increased the knowledge of the carotenoid metabolic pathway in plants. In this chapter a description of each step in the carotenoid synthesis pathway is presented and discussed.

  16. Production of anticancer polyenes through precursor-directed biosynthesis.

    Science.gov (United States)

    Clark, Benjamin R; O'Connor, Stephen; Fox, Deirdre; Leroy, Jacques; Murphy, Cormac D

    2011-09-21

    The biosynthesis of the pyrrolyl moiety of the fungal metabolite rumbrin originates from pyrrole-2-carboxylic acid. In an effort to produce novel derivatives with enhanced biological activity a series of substituted pyrrole-2-carboxylates were synthesised and incubated with the producing organism, Auxarthron umbrinum. Several 4-halo-pyrrole-2-carboxylic acids were incorporated into the metabolite yielding three new derivatives: 3-fluoro-, 3-chloro- and 3-bromo-isorumbrin, which were generated in milligram quantities enabling cytotoxicity assays to be conducted. The 3-chloro- and 3-bromo-isorumbrins had improved activity against HeLa cells compared with rumbrin; 3-bromoisorumbrin also showed dramatically improved activity towards a lung cancer cell line (A549).

  17. Egghead and brainiac are essential for glycosphingolipid biosynthesis in vivo

    DEFF Research Database (Denmark)

    Wandall, Hans H; Pizette, Sandrine; Pedersen, Johannes W

    2004-01-01

    glycosphingolipids and exhibit accumulation of the truncated precursor glycosphingolipids. Furthermore, we demonstrate that despite fundamental differences in the core structure of mammalian and Drosophila glycosphingolipids, the Drosophila egghead mutant can be rescued by introduction of the mammalian...... lactosylceramide glycosphingolipid biosynthetic pathway (Galbeta1-4Glcbeta1-Cer) using a human beta4-galactosyltransferase (beta4Gal-T6) transgene. Conversely, introduction of egghead in vertebrate cells (Chinese hamster ovary) resulted in near complete blockage of biosynthesis of glycosphingolipids...... and accumulation of Manbeta1-4Glcbeta1-Cer. The study demonstrates that glycosphingolipids are essential for development of complex organisms and suggests that the function of the Drosophila glycosphingolipids in development does not depend on the core structure....

  18. Biosynthesis of rare hexoses using microorganisms and related enzymes

    Directory of Open Access Journals (Sweden)

    Zijie Li

    2013-11-01

    Full Text Available Rare sugars, referred to as monosaccharides and their derivatives that rarely exist in nature, can be applied in many areas ranging from foodstuffs to pharmaceutical and nutrition industry, or as starting materials for various natural products and drug candidates. Unfortunately, an important factor restricting the utilization of rare sugars is their limited availability, resulting from limited synthetic methods. Nowadays, microbial and enzymatic transformations have become a very powerful tool in this field. This article reviews the biosynthesis and enzymatic production of rare ketohexoses, aldohexoses and sugar alcohols (hexitols, including D-tagatose, D-psicose, D-sorbose, L-tagatose, L-fructose, 1-deoxy-L-fructose, D-allose, L-glucose, L-talose, D-gulose, L-galactose, L-fucose, allitol, D-talitol, and L-sorbitol. New systems and robust catalysts resulting from advancements in genomics and bioengineering are also discussed.

  19. A Comparison between Chemical Synthesis Magnetite Nanoparticles and Biosynthesis Magnetite.

    Science.gov (United States)

    Kahani, Seyed Abolghasem; Yagini, Zahra

    2014-01-01

    The preparation of Fe3O4 from ferrous salt by air in alkaline aqueous solution at various temperatures was proposed. The synthetic magnetites have different particle size distributions. We studied the properties of the magnetite prepared by chemical methods compared with magnetotactic bacterial nanoparticles. The results show that crystallite size, morphology, and particle size distribution of chemically prepared magnetite at 293 K are similar to biosynthesis of magnetite. The new preparation of Fe3O4 helps to explain the mechanism of formation of magnetosomes in magnetotactic bacteria. The products are characterized by X-ray powder diffraction (XRD), infrared (IR) spectra, vibrating sample magnetometry (VSM), and scanning electron microscopy (SEM).

  20. De novo biosynthesis of Gastrodin in Escherichia coli.

    Science.gov (United States)

    Bai, Yanfen; Yin, Hua; Bi, Huiping; Zhuang, Yibin; Liu, Tao; Ma, Yanhe

    2016-05-01

    Gastrodin, a phenolic glycoside, is the key ingredient of Gastrodia elata, a notable herbal plant that has been used to treat various conditions in oriental countries for centuries. Gastrodin is extensively used clinically for its sedative, hypnotic, anticonvulsive and neuroprotective properties in China. Gastrodin is usually produced by plant extraction or chemical synthesis, which has many disadvantages. Herein, we report unprecedented microbial synthesis of gastrodin via an artificial pathway. A Nocardia carboxylic acid reductase, endogenous alcohol dehydrogenases and a Rhodiola glycosyltransferase UGT73B6 transformed 4-hydroxybenzoic acid, an intermediate of ubiquinone biosynthesis, into gastrodin in Escherichia coli. Pathway genes were overexpressed to enhance metabolic flux toward precursor 4-hydroxybenzyl alcohol. Furthermore, the catalytic properties of the UGT73B6 toward phenolic alcohols were improved through directed evolution. The finally engineered strain produced 545mgl(-1) gastrodin in 48h. This work creates a new route to produce gastrodin, instead of plant extractions and chemical synthesis.

  1. Solving the puzzles of cutin and suberin polymer biosynthesis.

    Science.gov (United States)

    Beisson, Fred; Li-Beisson, Yonghua; Pollard, Mike

    2012-06-01

    Cutin and suberin are insoluble lipid polymers that provide critical barrier functions to the cell wall of certain plant tissues, including the epidermis, endodermis and periderm. Genes that are specific to the biosynthesis of cutins and/or aliphatic suberins have been identified, mainly in Arabidopsis thaliana. They notably encode acyltransferases, oxidases and transporters, which may have either well-defined or more debatable biochemical functions. However, despite these advances, important aspects of cutin and suberin synthesis remain obscure. Central questions include whether fatty acyl monomers or oligomers are exported, and the extent of extracellular assembly and attachment to the cell wall. These issues are reviewed. Greater emphasis on chemistry and biochemistry will be required to solve these unknowns and link structure with function.

  2. Building lipid barriers: biosynthesis of cutin and suberin.

    Science.gov (United States)

    Pollard, Mike; Beisson, Fred; Li, Yonghua; Ohlrogge, John B

    2008-05-01

    Cutin and suberin are the polymer matrices for lipophilic cell wall barriers. These barriers control the fluxes of gases, water and solutes, and also play roles in protecting plants from biotic and abiotic stresses and in controlling plant morphology. Although they are ubiquitous, cutin and suberin are the least understood of the major plant extracellular polymers. The use of forward and reverse genetic approaches in Arabidopsis has led to the identification of oxidoreductase and acyltransferase genes involved in the biosynthesis of these polymers. However, major questions about the underlying polymer structure, biochemistry, and intracellular versus extracellular assembly remain to be resolved. The analysis of plant lines with modified cutins and suberins has begun to reveal the inter-relationships between the composition and function of these polymers.

  3. Cytochrome P450 as dimerization catalyst in diketopiperazine alkaloid biosynthesis.

    Science.gov (United States)

    Saruwatari, Takayoshi; Yagishita, Fumitoshi; Mino, Takashi; Noguchi, Hiroshi; Hotta, Kinya; Watanabe, Kenji

    2014-03-21

    As dimeric natural products frequently exhibit useful biological activities, identifying and understanding their mechanisms of dimerization is of great interest. One such compound is (−)-ditryptophenaline, isolated from Aspergillus flavus, which inhibits substance P receptor for potential analgesic and anti-inflammatory activity. Through targeted gene knockout in A. flavus and heterologous yeast gene expression, we determined for the first time the gene cluster and pathway for the biosynthesis of a dimeric diketopiperazine alkaloid. We also determined that a single cytochrome P450, DtpC, is responsible not only for pyrroloindole ring formation but also for concurrent dimerization of N-methylphenylalanyltryptophanyl diketopiperazine monomers into a homodimeric product. Furthermore, DtpC exhibits relaxed substrate specificity, allowing the formation of two new dimeric compounds from a non-native monomeric precursor, brevianamide F. A radical-mediated mechanism of dimerization is proposed.

  4. Polyketide biosynthesis in dinoflagellates: what makes it different?

    Science.gov (United States)

    Van Wagoner, Ryan M; Satake, Masayuki; Wright, Jeffrey L C

    2014-09-01

    Dinoflagellates produce unique polyketides characterized by their size and complexity. The biosynthesis of a limited number of such metabolites has been reported, with studies largely hampered by the low yield of compounds and the severe scrambling of label in the isotopically-labeled precursors. Nonetheless, of the successful biosynthetic experiments that have been reported, many surprising and unique processes have been discovered. This knowledge has been accessed through a series of biochemical labeling studies, and while limited molecular genetic data has been amassed, it is still in the early stages of development. In an attempt to meet this challenge, this review has compared some of the biosynthetic processes with similar ones identified in other microbes such as bacteria and myxobacteria, with the idea that similar genes and enzymes are employed by dinoflagellates.

  5. Biosynthesis of Nanoparticles by Microorganisms and Their Applications

    Directory of Open Access Journals (Sweden)

    Xiangqian Li

    2011-01-01

    Full Text Available The development of eco-friendly technologies in material synthesis is of considerable importance to expand their biological applications. Nowadays, a variety of inorganic nanoparticles with well-defined chemical composition, size, and morphology have been synthesized by using different microorganisms, and their applications in many cutting-edge technological areas have been explored. This paper highlights the recent developments of the biosynthesis of inorganic nanoparticles including metallic nanoparticles, oxide nanoparticles, sulfide nanoparticles, and other typical nanoparticles. Different formation mechanisms of these nanoparticles will be discussed as well. The conditions to control the size/shape and stability of particles are summarized. The applications of these biosynthesized nanoparticles in a wide spectrum of potential areas are presented including targeted drug delivery, cancer treatment, gene therapy and DNA analysis, antibacterial agents, biosensors, enhancing reaction rates, separation science, and magnetic resonance imaging (MRI. The current limitations and future prospects for the synthesis of inorganic nanoparticles by microorganisms are discussed.

  6. Biosynthesis of a Fully Functional Cyclotide inside Living Bacterial Cells

    Energy Technology Data Exchange (ETDEWEB)

    Camarero, J A; Kimura, R H; Woo, Y; Cantor, J; Shekhtman, A

    2007-04-05

    The cyclotide MCoTI-II is a powerful trypsin inhibitor recently isolated from the seeds of Momordica cochinchinensis, a plant member of cucurbitaceae family. We report for the first time the in vivo biosynthesis of natively-folded MCoTI-II inside live E. coli cells. Our biomimetic approach involves the intracellular backbone cyclization of a linear cyclotide-intein fusion precursor mediated by a modified protein splicing domain. The cyclized peptide then spontaneously folds into its native conformation. The use of genetically engineered E. coli cells containing mutations in the glutathione and thioredoxin reductase genes considerably improves the production of folded MCoTI-II in vivo. Biochemical and structural characterization of the recombinant MCoTI-II confirmed its identity. Biosynthetic access to correctly-folded cyclotides allows the possibility of generating cell-based combinatorial libraries that can be screened inside living cells for their ability to modulate or inhibit cellular processes.

  7. Molecular genetics of alkaloid biosynthesis in Nicotiana tabacum.

    Science.gov (United States)

    Dewey, Ralph E; Xie, Jiahua

    2013-10-01

    Alkaloids represent an extensive group of nitrogen-containing secondary metabolites that are widely distributed throughout the plant kingdom. The pyridine alkaloids of tobacco (Nicotiana tabacum L.) have been the subject of particularly intensive investigation, driven largely due to the widespread use of tobacco products by society and the role that nicotine (16) (see Fig. 1) plays as the primary compound responsible for making the consumption of these products both pleasurable and addictive. In a typical commercial tobacco plant, nicotine (16) comprises about 90% of the total alkaloid pool, with the alkaloids nornicotine (17) (a demethylated derivative of nicotine), anatabine (15) and anabasine (5) making up most of the remainder. Advances in molecular biology have led to the characterization of the majority of the genes encoding the enzymes directly responsible the biosynthesis of nicotine (16) and nornicotine (17), while notable gaps remain within the anatabine (15) and anabasine (5) biosynthetic pathways. Several of the genes involved in the transcriptional regulation and transport of nicotine (16) have also been elucidated. Investigations of the molecular genetics of tobacco alkaloids have not only provided plant biologists with insights into the mechanisms underlying the synthesis and accumulation of this important class of plant alkaloids, they have also yielded tools and strategies for modifying the tobacco alkaloid composition in a manner that can result in changing the levels of nicotine (16) within the leaf, or reducing the levels of a potent carcinogenic tobacco-specific nitrosamine (TSNA). This review summarizes recent advances in our understanding of the molecular genetics of alkaloid biosynthesis in tobacco, and discusses the potential for applying information accrued from these studies toward efforts designed to help mitigate some of the negative health consequences associated with the use of tobacco products.

  8. Phosphoribosyl Diphosphate (PRPP): Biosynthesis, Enzymology, Utilization, and Metabolic Significance.

    Science.gov (United States)

    Hove-Jensen, Bjarne; Andersen, Kasper R; Kilstrup, Mogens; Martinussen, Jan; Switzer, Robert L; Willemoës, Martin

    2017-03-01

    Phosphoribosyl diphosphate (PRPP) is an important intermediate in cellular metabolism. PRPP is synthesized by PRPP synthase, as follows: ribose 5-phosphate + ATP → PRPP + AMP. PRPP is ubiquitously found in living organisms and is used in substitution reactions with the formation of glycosidic bonds. PRPP is utilized in the biosynthesis of purine and pyrimidine nucleotides, the amino acids histidine and tryptophan, the cofactors NAD and tetrahydromethanopterin, arabinosyl monophosphodecaprenol, and certain aminoglycoside antibiotics. The participation of PRPP in each of these metabolic pathways is reviewed. Central to the metabolism of PRPP is PRPP synthase, which has been studied from all kingdoms of life by classical mechanistic procedures. The results of these analyses are unified with recent progress in molecular enzymology and the elucidation of the three-dimensional structures of PRPP synthases from eubacteria, archaea, and humans. The structures and mechanisms of catalysis of the five diphosphoryltransferases are compared, as are those of selected enzymes of diphosphoryl transfer, phosphoryl transfer, and nucleotidyl transfer reactions. PRPP is used as a substrate by a large number phosphoribosyltransferases. The protein structures and reaction mechanisms of these phosphoribosyltransferases vary and demonstrate the versatility of PRPP as an intermediate in cellular physiology. PRPP synthases appear to have originated from a phosphoribosyltransferase during evolution, as demonstrated by phylogenetic analysis. PRPP, furthermore, is an effector molecule of purine and pyrimidine nucleotide biosynthesis, either by binding to PurR or PyrR regulatory proteins or as an allosteric activator of carbamoylphosphate synthetase. Genetic analyses have disclosed a number of mutants altered in the PRPP synthase-specifying genes in humans as well as bacterial species.

  9. Genes and enzymes of ectoine biosynthesis in halotolerant methanotrophs.

    Science.gov (United States)

    Reshetnikov, Alexander S; Khmelenina, Valentina N; Mustakhimov, Ildar I; Trotsenko, Yuri A

    2011-01-01

    Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) is a widely distributed compatible solute accumulated by halophilic and halotolerant microorganisms to prevent osmotic stress in highly saline environments. Ectoine as a highly water keeping compound stabilizing biomolecules and whole cells can be used in scientific work, cosmetics, and medicine. Detailed understanding of the organization/regulation of the ectoine biosynthetic pathway in various producers is an active area of research. Here we review current knowledge on some genetic and enzymatic aspects of ectoine biosynthesis in halophilic and halotolerant methanotrophs. By using PCR methodology, the genes coding for the specific enzymes of ectoine biosynthesis, diaminobutyric acid (DABA) aminotransferase (EctB), DABA acetyltransferase (EctA), and ectoine synthase (EctC), were identified in several methanotrophic species. Organization of these genes in either ectABC or ectABC-ask operons, the latter additionally encoding aspartate kinase isozyme (Ask), correlated well with methanotroph halotolerance and intracellular ectoine level. A new gene, ectR1 encoding the MarR-like transcriptional regulatory protein EctR1, negatively controlling transcription of ectoine biosynthetic genes was found upstream of ectABC-ask operon in Methylomicrobium alcaliphilum 20Z. The ectR-like genes were also found in halotolerant methanol utilizers Methylophaga alcalica and Methylophaga thalassica as well as in several genomes of nonmethylotrophic species. The His(6)-tagged DABA acetyltransferases from Mm. alcaliphilum, M. alcalica, and M. thalassica were purified and the enzyme properties were found to correlate with the ecophysiologies of these bacteria. All these discoveries should be very helpful for better understanding the biosynthetic mechanism of this important natural compound, and for the targeted metabolic engineering of its producers.

  10. Creatine biosynthesis and transport in health and disease.

    Science.gov (United States)

    Joncquel-Chevalier Curt, Marie; Voicu, Pia-Manuela; Fontaine, Monique; Dessein, Anne-Frédérique; Porchet, Nicole; Mention-Mulliez, Karine; Dobbelaere, Dries; Soto-Ares, Gustavo; Cheillan, David; Vamecq, Joseph

    2015-12-01

    Creatine is physiologically provided equally by diet and by endogenous synthesis from arginine and glycine with successive involvements of arginine glycine amidinotransferase [AGAT] and guanidinoacetate methyl transferase [GAMT]. A specific plasma membrane transporter, creatine transporter [CRTR] (SLC6A8), further enables cells to incorporate creatine and through uptake of its precursor, guanidinoacetate, also directly contributes to creatine biosynthesis. Breakthrough in the role of creatine has arisen from studies on creatine deficiency disorders. Primary creatine disorders are inherited as autosomal recessive (mutations affecting GATM [for glycine-amidinotransferase, mitochondrial]) and GAMT genes) or X-linked (SLC6A8 gene) traits. They have highlighted the role of creatine in brain functions altered in patients (global developmental delay, intellectual disability, behavioral disorders). Creatine modulates GABAergic and glutamatergic cerebral pathways, presynaptic CRTR (SLC6A8) ensuring re-uptake of synaptic creatine. Secondary creatine disorders, addressing other genes, have stressed the extraordinary imbrication of creatine metabolism with many other cellular pathways. This high dependence on multiple pathways supports creatine as a cellular sensor, to cell methylation and energy status. Creatine biosynthesis consumes 40% of methyl groups produced as S-adenosylmethionine, and creatine uptake is controlled by AMP activated protein kinase, a ubiquitous sensor of energy depletion. Today, creatine is considered as a potential sensor of cell methylation and energy status, a neurotransmitter influencing key (GABAergic and glutamatergic) CNS neurotransmission, therapeutic agent with anaplerotic properties (towards creatine kinases [creatine-creatine phosphate cycle] and creatine neurotransmission), energetic and antioxidant compound (benefits in degenerative diseases through protection against energy depletion and oxidant species) with osmolyte behavior (retention of

  11. A mathematical model of N-linked glycoform biosynthesis.

    Science.gov (United States)

    Umaña, P; Bailey, J E

    1997-09-20

    Metabolic engineering of N-linked oligosaccharide biosynthesis to produce novel glycoforms or glycoform distributions of a recombinant glycoprotein can potentially lead to an improved therapeutic performance of the glycoprotein product. Effective engineering of this pathway to maximize the fractions of beneficial glycoforms within the glycoform population of a target glycoprotein can be aided by a mathematical model of the N-linked glycosylation process. A mathematical model is presented here, whose main function is to calculate the expected qualitative trends in the N-linked oligosaccharide distribution resulting from changes in the levels of one or more enzymes involved in the network of enzyme-catalyzed reactions that accomplish N-linked oligosaccharide biosynthesis. It consists of mass balances for 33 different oligosaccharide species N-linked to a specified protein that is being transported through the different compartments of the Golgi complex. Values of the model parameters describing Chinese hamster ovary (CHO) cells were estimated from literature information. A basal set of kinetic parameters for the enzyme-catalyzed reactions acting on free oligosaccharide substrates was also obtained from the literature. The solution of the system for this basal set of parameters gave a glycoform distribution consisting mainly of complex-galactosylated oligosaccharides distributed in structures with different numbers of antennae in a fashion similar to that observed for various recombinant proteins produced in CHO cells. Other simulations indicate that changes in the oligosaccharide distribution could easily result from alteration in glycoprotein productivity within the range currently attainable in industry. The overexpression of N-acetylglucosaminyltransferase III in CHO cells was simulated under different conditions to test the main function of the model. These simulations allow a comparison of different strategies, such as simultaneous overexpression of several

  12. Glycosaminoglycan polysaccharide biosynthesis and production: today and tomorrow.

    Science.gov (United States)

    DeAngelis, Paul L

    2012-04-01

    Glycosaminoglycans [GAGs] are essential heteropolysaccharides in vertebrate tissues that are also, in certain cases, employed as virulence factors by microbes. Hyaluronan [HA], heparin, and chondroitin sulfate [CS] are GAGs currently used in various medical applications and together are multi-billion dollar products thus targets for production by animal-free manufacture. By using bacteria as the source of GAGs, the pathogen's sword may be converted into a plowshare to help avoid potential liabilities springing from the use of animal-derived GAGs including adventitious agents (e.g., prions, pathogens), antigenicity, degradation of the environment, and depletion of endangered species. HA from microbes, which have a chemical structure identical to human HA, has already been commercialized and sold at the ton-scale. Substantial progress towards microbial heparin and CS has been made, but these vertebrate polymers are more complicated structurally than the unsulfated bacterial polysaccharide precursors thus require additional processing steps. This review provides an overview of GAG structure, medical applications, microbial biosynthesis, and the state of bacterial GAG production systems. Representatives of all glycosyltransferase enzymes that polymerize the sugar chains of the three main GAGs have been identified and serve as the core technology to harness, but the proteins involved in sugar precursor formation and chain export steps of biosynthesis are also essential to the GAG production process. In addition, this review discusses future directions and potential important issues. Overall, this area is poised to make great headway to produce safer (both increased purity and more secure supply chains) non-animal GAG-based therapeutics.

  13. Insights into the biosynthesis and assembly of cryptophycean phycobiliproteins.

    Science.gov (United States)

    Overkamp, Kristina E; Gasper, Raphael; Kock, Klaus; Herrmann, Christian; Hofmann, Eckhard; Frankenberg-Dinkel, Nicole

    2014-09-26

    Phycobiliproteins are employed by cyanobacteria, red algae, glaucophytes, and cryptophytes for light-harvesting and consist of apoproteins covalently associated with open-chain tetrapyrrole chromophores. Although the majority of organisms assemble the individual phycobiliproteins into larger aggregates called phycobilisomes, members of the cryptophytes use a single type of phycobiliprotein that is localized in the thylakoid lumen. The cryptophyte Guillardia theta (Gt) uses phycoerythrin PE545 utilizing the uncommon chromophore 15,16-dihydrobiliverdin (DHBV) in addition to phycoerythrobilin (PEB). Both the biosynthesis and the attachment of chromophores to the apophycobiliprotein have not yet been investigated for cryptophytes. In this study, we identified and characterized enzymes involved in PEB biosynthesis. In addition, we present the first in-depth biochemical characterization of a eukaryotic phycobiliprotein lyase (GtCPES). Plastid-encoded HO (GtHo) was shown to convert heme into biliverdin IXα providing the substrate with a putative nucleus-encoded DHBV:ferredoxin oxidoreductase (GtPEBA). A PEB:ferredoxin oxidoreductase (GtPEBB) was found to convert DHBV to PEB, which is the substrate for the phycobiliprotein lyase GtCPES. The x-ray structure of GtCPES was solved at 2.0 Å revealing a 10-stranded β-barrel with a modified lipocalin fold. GtCPES is an S-type lyase specific for binding of phycobilins with reduced C15=C16 double bonds (DHBV and PEB). Site-directed mutagenesis identified residues Glu-136 and Arg-146 involved in phycobilin binding. Based on the crystal structure, a model for the interaction of GtCPES with the apophycobiliprotein CpeB is proposed and discussed.

  14. Biosynthesis and structural characterization of silver nanoparticles from bacterial isolates

    Energy Technology Data Exchange (ETDEWEB)

    Zaki, Sahar, E-mail: saharzaki@yahoo.com [Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research and Technology Applications, Alexandria, 21934 New Burgelarab City (Egypt); El Kady, M.F. [Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), Mubarak City for Scientific Research and Technology Applications, Alexandria (Egypt); Abd-El-Haleem, Desouky [Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research and Technology Applications, Alexandria, 21934 New Burgelarab City (Egypt)

    2011-10-15

    Graphical abstract: In this study five bacterial isolates belong to different genera were found to be able to biosynthesize silver nanoparticles. Biosynthesis and spectral characterization are reported here. Highlights: {yields} About 300 bacterial isolates were screened for their ability to produce nanosilvers {yields} Five of them were potential candidates for synthesis of silver nanoparticles {yields} Production of silver nanoparticles was examined using UV-Vis, XRD, SEM and EDS. {yields} The presence of nanoparticles with all five bacterial isolates was confirmed. -- Abstract: This study aimed to develop a green process for biosynthesis of silver nanomaterials by some Egyptian bacterial isolates. This target was achieved by screening an in-house culture collection consists of 300 bacterial isolates for silver nanoparticle formation. Through screening process, it was observed that strains belonging to Escherichia coli (S30, S78), Bacillus megaterium (S52), Acinetobacter sp. (S7) and Stenotrophomonas maltophilia (S54) were potential candidates for synthesis of silver nanoparticles. The extracellular production of silver nanoparticles by positive isolates was investigated by UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results demonstrated that UV-visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy micrograph showed formation of silver nanoparticles in the range of 15-50 nm. XRD-spectrum of the silver nanoparticles exhibited 2{theta} values corresponding to the silver nanocrystal that produce in hexagonal and cubic crystal configurations with different plane of orientation. In addition, the signals of the silver atoms were observed by EDS-spectrum analysis that confirms the presence of silver nanoparticles (Ag

  15. Expression and mapping of anthocyanin biosynthesis genes in carrot.

    Science.gov (United States)

    Yildiz, Mehtap; Willis, David K; Cavagnaro, Pablo F; Iorizzo, Massimo; Abak, Kazim; Simon, Philipp W

    2013-07-01

    Anthocyanin gene expression has been extensively studied in leaves, fruits and flowers of numerous plants. Little, however, is known about anthocyanin accumulation in roots of carrots or other species. We quantified expression of six anthocyanin biosynthetic genes [phenylalanine ammonia-lyase (PAL3), chalcone synthase (CHS1), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR1), leucoanthocyanidin dioxygenase (LDOX2), and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT)] in three carrot inbreds with contrasting root color: solid purple (phloem and xylem); purple outer phloem/orange xylem; and orange phloem and xylem. Transcripts for five of these genes (CHS1, DFR1, F3H, LDOX2, PAL3) accumulated at high levels in solid purple carrots, less in purple-orange carrot, and low or no transcript in orange carrots. Gene expression coincided with anthocyanin accumulation. In contrast, UFGT expression was comparable in purple and orange carrots and relatively unchanged during root development. In addition, five anthocyanin biosynthesis genes [FLS1 (flavonol synthase), F3H, LDOX2, PAL3, and UFGT] and three anthocyanin transcription factors (DcEFR1, DcMYB3 and DcMYB5) were mapped in a population segregating for the P 1 locus that conditions purple root color. P 1 mapped to chromosome 3 and of the eight anthocyanin biosynthesis genes, only F3H and FLS1 were linked to P 1. The gene expression and mapping data suggest a coordinated regulatory control of anthocyanin expression in carrot root and establish a framework for studying the anthocyanin pathway in carrots, and they also suggest that none of the genes evaluated is a candidate for P 1.

  16. Biosynthesis and translocation of unsulfated acyltrehaloses in Mycobacterium tuberculosis.

    Science.gov (United States)

    Belardinelli, Juan Manuel; Larrouy-Maumus, Gérald; Jones, Victoria; Sorio de Carvalho, Luiz Pedro; McNeil, Michael R; Jackson, Mary

    2014-10-03

    A number of species-specific polymethyl-branched fatty acid-containing trehalose esters populate the outer membrane of Mycobacterium tuberculosis. Among them, 2,3-diacyltrehaloses (DAT) and penta-acyltrehaloses (PAT) not only play a structural role in the cell envelope but also contribute to the ability of M. tuberculosis to multiply and persist in the infected host, promoting the intracellular survival of the bacterium and modulating host immune responses. The nature of the machinery, topology, and sequential order of the reactions leading to the biosynthesis, assembly, and export of these complex glycolipids to the cell surface are the object of the present study. Our genetic and biochemical evidence corroborates a model wherein the biosynthesis and translocation of DAT and PAT to the periplasmic space are coupled and topologically split across the plasma membrane. The formation of DAT occurs on the cytosolic face of the plasma membrane through the action of PapA3, FadD21, and Pks3/4; that of PAT occurs on the periplasmic face via transesterification reactions between DAT substrates catalyzed by the acyltransferase Chp2 (Rv1184c). The integral membrane transporter MmpL10 is essential for DAT to reach the cell surface, and its presence in the membrane is required for Chp2 to be active. Disruption of mmpL10 or chp2 leads to an important build-up of DAT inside the cells and to the formation of a novel form of unsulfated acyltrehalose esterified with polymethyl-branched fatty acids normally found in sulfolipids that is translocated to the cell surface.

  17. Abscisic Acid Biosynthesis in Leaves and Roots of Xanthium strumarium.

    Science.gov (United States)

    Creelman, R A; Gage, D A; Stults, J T; Zeevaart, J A

    1987-11-01

    RESEARCH ON THE BIOSYNTHESIS OF ABSCISIC ACID (ABA) HAS FOCUSED PRIMARILY ON TWO PATHWAYS: (a) the direct pathway from farnesyl pyrophosphate, and (b) the indirect pathway involving a carotenoid precursor. We have investigated which biosynthetic pathway is operating in turgid and stressed Xanthium leaves, and in stressed Xanthium roots using long-term incubations in (18)O(2). It was found that in stressed leaves three atoms of (18)O from (18)O(2) are incorporated into the ABA molecule, and that the amount of (18)O incorporated increases with time. One (18)O atom is incorporated rapidly into the carboxyl group of ABA, whereas the other two atoms are very slowly incorporated into the ring oxygens. The fourth oxygen atom in the carboxyl group of ABA is derived from water. ABA from stressed roots of Xanthium incubated in (18)O(2) shows a labeling pattern similar to that of ABA in stressed leaves, but with incorporation of more (18)O into the tertiary hydroxyl group at C-1' after 6 and 12 hours than found in ABA from stressed leaves. It is proposed that the precursors to stress-induced ABA are xanthophylls, and that a xanthophyll lacking an oxygen function at C-6 (carotenoid numbering scheme) plays a crucial role in ABA biosynthesis in Xanthium roots. In turgid Xanthium leaves, (18)O is incorporated into ABA to a much lesser extent than it is in stressed leaves, whereas exogenously applied (14)C-ABA is completely catabolized within 48 hours. This suggests that ABA in turgid leaves is either (a) made via a biosynthetic pathway which is different from the one in stressed leaves, or (b) has a half-life on the order of days as compared with a half-life of 15.5 hours in water-stressed Xanthium leaves. Phaseic acid showed a labeling pattern similar to that of ABA, but with an additional (18)O incorporated during 8'-hydroxylation of ABA to phaseic acid.

  18. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  19. Cloning and characterization of the polyether salinomycin biosynthesis gene cluster of Streptomyces albus XM211.

    Science.gov (United States)

    Jiang, Chunyan; Wang, Hougen; Kang, Qianjin; Liu, Jing; Bai, Linquan

    2012-02-01

    Salinomycin is widely used in animal husbandry as a food additive due to its antibacterial and anticoccidial activities. However, its biosynthesis had only been studied by feeding experiments with isotope-labeled precursors. A strategy with degenerate primers based on the polyether-specific epoxidase sequences was successfully developed to clone the salinomycin gene cluster. Using this strategy, a putative epoxidase gene, slnC, was cloned from the salinomycin producer Streptomyces albus XM211. The targeted replacement of slnC and subsequent trans-complementation proved its involvement in salinomycin biosynthesis. A 127-kb DNA region containing slnC was sequenced, including genes for polyketide assembly and release, oxidative cyclization, modification, export, and regulation. In order to gain insight into the salinomycin biosynthesis mechanism, 13 gene replacements and deletions were conducted. Including slnC, 7 genes were identified as essential for salinomycin biosynthesis and putatively responsible for polyketide chain release, oxidative cyclization, modification, and regulation. Moreover, 6 genes were found to be relevant to salinomycin biosynthesis and possibly involved in precursor supply, removal of aberrant extender units, and regulation. Sequence analysis and a series of gene replacements suggest a proposed pathway for the biosynthesis of salinomycin. The information presented here expands the understanding of polyether biosynthesis mechanisms and paves the way for targeted engineering of salinomycin activity and productivity.

  20. Regulation of Sterol Biosynthesis in the Human Fungal Pathogen Aspergillus fumigatus: Opportunities for Therapeutic Development

    Science.gov (United States)

    Dhingra, Sourabh; Cramer, Robert A.

    2017-01-01

    Sterols are a major component of eukaryotic cell membranes. For human fungal infections caused by the filamentous fungus Aspergillus fumigatus, antifungal drugs that target sterol biosynthesis and/or function remain the standard of care. Yet, an understanding of A. fumigatus sterol biosynthesis regulatory mechanisms remains an under developed therapeutic target. The critical role of sterol biosynthesis regulation and its interactions with clinically relevant azole drugs is highlighted by the basic helix loop helix (bHLH) class of transcription factors known as Sterol Regulatory Element Binding Proteins (SREBPs). SREBPs regulate transcription of key ergosterol biosynthesis genes in fungi including A. fumigatus. In addition, other emerging regulatory pathways and target genes involved in sterol biosynthesis and drug interactions provide additional opportunities including the unfolded protein response, iron responsive transcriptional networks, and chaperone proteins such as Hsp90. Thus, targeting molecular pathways critical for sterol biosynthesis regulation presents an opportunity to improve therapeutic options for the collection of diseases termed aspergillosis. This mini-review summarizes our current understanding of sterol biosynthesis regulation with a focus on mechanisms of transcriptional regulation by the SREBP family of transcription factors. PMID:28203225

  1. Sulfur deficiency–induced repressor proteins optimize glucosinolate biosynthesis in plants

    Science.gov (United States)

    Aarabi, Fayezeh; Kusajima, Miyuki; Tohge, Takayuki; Konishi, Tomokazu; Gigolashvili, Tamara; Takamune, Makiko; Sasazaki, Yoko; Watanabe, Mutsumi; Nakashita, Hideo; Fernie, Alisdair R.; Saito, Kazuki; Takahashi, Hideki; Hubberten, Hans-Michael; Hoefgen, Rainer; Maruyama-Nakashita, Akiko

    2016-01-01

    Glucosinolates (GSLs) in the plant order of the Brassicales are sulfur-rich secondary metabolites that harbor antipathogenic and antiherbivory plant-protective functions and have medicinal properties, such as carcinopreventive and antibiotic activities. Plants repress GSL biosynthesis upon sulfur deficiency (−S); hence, field performance and medicinal quality are impaired by inadequate sulfate supply. The molecular mechanism that links –S to GSL biosynthesis has remained understudied. We report here the identification of the –S marker genes sulfur deficiency induced 1 (SDI1) and SDI2 acting as major repressors controlling GSL biosynthesis in Arabidopsis under –S condition. SDI1 and SDI2 expression negatively correlated with GSL biosynthesis in both transcript and metabolite levels. Principal components analysis of transcriptome data indicated that SDI1 regulates aliphatic GSL biosynthesis as part of –S response. SDI1 was localized to the nucleus and interacted with MYB28, a major transcription factor that promotes aliphatic GSL biosynthesis, in both yeast and plant cells. SDI1 inhibited the transcription of aliphatic GSL biosynthetic genes by maintaining the DNA binding composition in the form of an SDI1-MYB28 complex, leading to down-regulation of GSL biosynthesis and prioritization of sulfate usage for primary metabolites under sulfur-deprived conditions.

  2. Recent advances in the elucidation of enzymatic function in natural product biosynthesis [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Tan Gao-Yi

    2015-12-01

    Full Text Available With the successful production of artemisinic acid in yeast, the promising potential of synthetic biology for natural product biosynthesis is now being realized. The recent total biosynthesis of opioids in microbes is considered to be another landmark in this field. The importance and significance of enzymes in natural product biosynthetic pathways have been re-emphasized by these advancements. Therefore, the characterization and elucidation of enzymatic function in natural product biosynthesis are undoubtedly fundamental for the development of new drugs and the heterologous biosynthesis of active natural products. Here, discoveries regarding enzymatic function in natural product biosynthesis over the past year are briefly reviewed.

  3. Recent advances in the elucidation of enzymatic function in natural product biosynthesis [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Gao-Yi Tan

    2016-02-01

    Full Text Available With the successful production of artemisinic acid in yeast, the promising potential of synthetic biology for natural product biosynthesis is now being realized. The recent total biosynthesis of opioids in microbes is considered to be another landmark in this field. The importance and significance of enzymes in natural product biosynthetic pathways have been re-emphasized by these advancements. Therefore, the characterization and elucidation of enzymatic function in natural product biosynthesis are undoubtedly fundamental for the development of new drugs and the heterologous biosynthesis of active natural products. Here, discoveries regarding enzymatic function in natural product biosynthesis over the past year are briefly reviewed.

  4. Identification of novel bacterial histidine biosynthesis inhibitors using docking, ensemble rescoring, and whole-cell assays

    DEFF Research Database (Denmark)

    Henriksen, Signe Teuber; Liu, J.; Estiu, G.;

    2010-01-01

    in the early stages of drug discovery attractive if sufficient accuracy can be achieved. Computational target identification using systems-level methods suggested the histidine biosynthesis pathway as an attractive target against S. aureus. Potential inhibitors for the pathway were identified through docking...... histidine biosynthesis pathway, which is predicted to be essential for bacterial biomass productions. Virtual screening of a library of similar to 10(6) compounds identified 49 potential inhibitors of three enzymes of this pathway. Eighteen representative compounds were directly tested on three S. aureus...... of this novel strategy to the histidine biosynthesis pathway....

  5. Precursor Amino Acids Inhibit Polymyxin E Biosynthesis in Paenibacillus polymyxa, Probably by Affecting the Expression of Polymyxin E Biosynthesis-Associated Genes

    Directory of Open Access Journals (Sweden)

    Zhiliang Yu

    2015-01-01

    Full Text Available Polymyxin E belongs to cationic polypeptide antibiotic bearing four types of direct precursor amino acids including L-2,4-diaminobutyric acid (L-Dab, L-Leu, D-Leu, and L-Thr. The objective of this study is to evaluate the effect of addition of precursor amino acids during fermentation on polymyxin E biosynthesis in Paenibacillus polymyxa. The results showed that, after 35 h fermentation, addition of direct precursor amino acids to certain concentration significantly inhibited polymyxin E production and affected the expression of genes involved in its biosynthesis. L-Dab repressed the expression of polymyxin synthetase genes pmxA and pmxE, as well as 2,4-diaminobutyrate aminotransferase gene ectB; both L-Leu and D-Leu repressed the pmxA expression. In addition, L-Thr affected the expression of not only pmxA, but also regulatory genes spo0A and abrB. As L-Dab precursor, L-Asp repressed the expression of ectB, pmxA, and pmxE. Moreover, it affected the expression of spo0A and abrB. In contrast, L-Phe, a nonprecursor amino acid, had no obvious effect on polymyxin E biosynthesis and those biosynthesis-related genes expression. Taken together, our data demonstrated that addition of precursor amino acids during fermentation will inhibit polymyxin E production probably by affecting the expression of its biosynthesis-related genes.

  6. Genetics of subtilin and nisin biosyntheses: biosynthesis of lantibiotics.

    Science.gov (United States)

    Entian, K D; de Vos, W M

    1996-02-01

    Several peptide antibiotics have been described as potent inhibitors of bacterial growth. With respect to their biosynthesis, they can be divided into two classes: (i) those that are synthesized by a non-ribosomal mechanism, and (ii) those that are ribosomally synthesized. Subtilin and nisin belong to the ribosomally synthesized peptide antibiotics. They contain the rare amino acids dehydroalanine, dehydrobutyrine, meso-lanthionine, and 3-methyllanthionine. They are derived from prepeptides which are post-translationally modified and have been termed lantibiotics because of their characteristic lanthionine bridges (Schnell et al. 1988). Nisin is the most prominent lantibiotic and is used as a food preservative due to its high potency against certain gram-positive bacteria (Mattick & Hirsch 1944, 1947; Rayman & Hurst 1984). It is produced by Lactococcus lactis strains belonging to serological group N. The potent bactericidal activities of nisin and other lantibiotics are based on depolarization of energized bacterial cytoplasmic membranes. Breakdown of the membrane potential is initiated by the formation of pores through which molecules of low molecular weight are released. A trans-negative membrane potential of 50 to 100 mV is necessary for pore formation by nisin (Ruhr & Sahl 1985; Sahl et al. 1987). Nisin occurs as a partially amphiphilic molecule (Van de Ven et al. 1991). Apart from the detergent-like effect of nisin on cytoplasmic membranes, an inhibition of murein synthesis has also been discussed as the primary effect (Reisinger et al. 1980). In several countries nisin is used to prevent the growth of clostridia in cheese and canned food. The nisin peptide structure was first described by Gross & Morall (1971), and its structural gene was isolated in 1988 (Buchman et al. 1988; Kaletta & Entian 1989). Nisin has two natural variants, nisin A, and nisin Z, which differ in a single amino acid residue at position 27 (histidin in nisin A is replaced by asparagin in

  7. Metabolic engineering of chloroplasts for artemisinic acid biosynthesis and impact on plant growth

    Indian Academy of Sciences (India)

    Bhawna Saxena; Mayavan Subramaniyan; Karan Malhotra; Neel Sarovar Bhavesh; Shobha Devi Potlakayala; Shashi Kumar

    2014-03-01

    Chloroplasts offer high-level transgene expression and transgene containment due to maternal inheritance, and are ideal hosts for biopharmaceutical biosynthesis via multigene engineering. To exploit these advantages, we have expressed 12 enzymes in chloroplasts for the biosynthesis of artemisinic acid (precursor of artemisinin, antimalarial drug) in an alternative plant system. Integration of transgenes into the tobacco chloroplast genome via homologous recombination was confirmed by molecular analysis, and biosynthesis of artemisinic acid in plant leaf tissues was detected with the help of 13C NMR and ESI-mass spectrometry. The excess metabolic flux of isopentenyl pyrophosphate generated by an engineered mevalonate pathway was diverted for the biosynthesis of artemisinic acid. However, expression of megatransgenes impacted the growth of the transplastomic plantlets. By combining two exogenous pathways, artemisinic acid was produced in transplastomic plants, which can be improved further using better metabolic engineering strategies for commercially viable yield of desirable isoprenoid products.

  8. Identification of Protein-Protein Interactions Involved in Pectin Biosynthesis in the golgi Apparatus

    DEFF Research Database (Denmark)

    Lund, Christian Have

    GALACTURONOSYLTRANSFERASE1 (GAUT1) and GAUT7 has beesn identified and is essential for pectin biosynthesis. Interestingly, GAUT1 has been shown to be proteolytic processed from its transmembrane anchor domain and its catalytic domain is retained by GAUT7, thus ensuring biosynthesis of HG in the Golgi apparatus. Many...... methods exist in identifying protein-protein interaction (PPI) but many of these are developed for other organisms than plants and are most applicable for PPI detection in other organelles than the Golgi apparatus where pectin biosynthesis occurs. In this work, different PPI detection methods are examined...... for their ability to detect PPI inside the Golgi lumen. The first method tested was the commercially available splitubiquitin system from Dualsystems Biotech AG. This was applied to test binary interactions between proteins involved in HG and Rhamnogalacturonan I (RG-I) biosynthesis (see Manuscript II...

  9. Regulatory genes and environmental regulation of amylovoran biosynthesis in Erwinia amylovora

    Science.gov (United States)

    The requirement of the exopolysaccharide amylovoran for Erwinia amylovora pathogenesis is well documented. However, regulation of amylovoran biosynthesis has not been comprehensively studied. We have previously reported that amylovoran production is strain-dependent in E. amylovora isolates. We have...

  10. LOCALIZATION OF THE PATHWAY OF THE PENICILLIN BIOSYNTHESIS IN PENICILLIUM-CHRYSOGENUM

    NARCIS (Netherlands)

    MULLER, WH; VANDERKRIFT, TP; KROUWER, AJJ; WOSTEN, HAB; VANDERVOORT, LHM; SMAAL, EB; VERKLEIJ, AJ

    1991-01-01

    The localization of the enzymes involved in penicillin biosynthesis in Penicillium chrysogenum hyphae has been studied by immunological detection methods in combination with electron microscopy and cell fractionation. The results suggest a complicated pathway involving different intracellular locati

  11. Cantharidin biosynthesis in a blister beetle: inhibition by 6-fluoromevalonate causes chemical disarmament.

    Science.gov (United States)

    Carrel, J E; Doom, J P; McCormick, J P

    1986-07-15

    Biosynthesis of cantharidin in a blister beetle, Lytta polita, is effectively inhibited by 6-fluoromevalonate. Inhibition is attributed specifically to the fluorine substituent. Biochemical inhibition has not been demonstrated previously for an arthropod's defensive substance.

  12. Tomato strigolactones are derived from carotenoids and their biosynthesis is promoted by phosphate starvation

    NARCIS (Netherlands)

    Lopez Raez, J.A.; Charnikhova, T.; Gomez-Roldan, M.V.; Matusova, R.; Kohlen, W.; Vos, de C.H.; Verstappen, F.W.A.; Puech-Pages, V.; Becard, G.; Mulder, P.P.J.; Bouwmeester, H.J.

    2008-01-01

    Strigolactones are rhizosphere signalling compounds that mediate host location in arbuscular mycorrhizal (AM) fungi and parasitic plants. Here, the regulation of the biosynthesis of strigolactones is studied in tomato (Solanum lycopersicum). Strigolactone production under phosphate starvation, in th

  13. Magnesium affects rubber biosynthesis and particle stability in Ficus elastica, Hevea brasiliensis and Parthenium argentatum

    Science.gov (United States)

    Natural rubber biosynthesis occurs in laticifers of Ficus elastica and Hevea brasiliensis, and in parenchyma cells of Parthenium argentatum. Natural rubber is synthesized by rubber transferase using allylic pyrophosphates as initiators, isopentenyl pyrophosphate as monomeric substrate and magnesium ...

  14. Reconstitution of a fungal meroterpenoid biosynthesis reveals the involvement of a novel family of terpene cyclases

    Science.gov (United States)

    Itoh, Takayuki; Tokunaga, Kinya; Matsuda, Yudai; Fujii, Isao; Abe, Ikuro; Ebizuka, Yutaka; Kushiro, Tetsuo

    2010-10-01

    Meroterpenoids are hybrid natural products of both terpenoid and polyketide origin. We identified a biosynthetic gene cluster that is responsible for the production of the meroterpenoid pyripyropene in the fungus Aspergillus fumigatus through reconstituted biosynthesis of up to five steps in a heterologous fungal expression system. The cluster revealed a previously unknown terpene cyclase with an unusual sequence and protein primary structure. The wide occurrence of this sequence in other meroterpenoid and indole-diterpene biosynthetic gene clusters indicates the involvement of these enzymes in the biosynthesis of various terpenoid-bearing metabolites produced by fungi and bacteria. In addition, a novel polyketide synthase that incorporated nicotinyl-CoA as the starter unit and a prenyltransferase, similar to that in ubiquinone biosynthesis, was found to be involved in the pyripyropene biosynthesis. The successful production of a pyripyropene analogue illustrates the catalytic versatility of these enzymes for the production of novel analogues with useful biological activities.

  15. A novel type of geosmin biosynthesis in myxobacteria.

    Science.gov (United States)

    Dickschat, Jeroen S; Bode, Helge B; Mahmud, Taifo; Müller, Rolf; Schulz, Stefan

    2005-06-24

    The biosynthesis of geosmin (1) and (1(10)E,5E)-germacradien-11-ol (2), two volatile terpenoid compounds emitted by the myxobacteria Myxococcus xanthus and Stigmatella aurantiaca, was investigated in feeding experiments with different labeled precursors. In these experiments, the volatiles released by the cell cultures grown on agar plates were collected with a closed-loop stripping apparatus (CLSA) and analyzed by GC-MS. [(2)H(10)]Leucine and [4,4,4,5,5,5-(2)H(6)]dimethylacrylate were fed to wild-type strains and bkd mutant strains, which are impaired in the degradation of leucine to isovaleryl-CoA. [(2)H(10)]Leucine was incorporated into 1 and 2 only by the wild-type strains via the biosynthetic pathway that involves leucine degradation and branching into the mevalonate pathway. Dimethylacrylyl-CoA (DMA-CoA) is an intermediate in the leucine degradation and in the recently discovered pathway from HMG-CoA to isovaleryl-CoA. The corresponding free acid, [4,4,4,5,5,5-(2)H(6)]dimethylacrylic acid, was incorporated into 1 and 2 only by the mutants impaired in leucine degradation. [4,4,6,6,6-(2)H(5)]Mevalonic acid lactone (12) was synthesized and fed to M. xanthus and S. aurantiaca wild-type strains and a double mutant strain of M. xanthus. This strain does not degrade leucine and is impaired in the reduction of 3-hydroxy-3-methylglutaryl-CoA to mevalonic acid. The mass spectral analysis of labeled 1 and 2 obtained in these feeding experiments led to a biosynthetic scheme to 1 with intermediate 2. This pathway differs from that observed in the liverwort Fossombronia pusilla and thus suggests microbial geosmin biosynthesis following a route different from that in liverworts. Our results are supported by a 1,2-hydride shift of the tertiary hydrogen atom at C-4a into the ring opposite to that in F. pusilla.

  16. Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2009-01-01

    Full Text Available Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS, which catalyzes the first committed step in sterol biosynthesis, (d allylamines, inhibitors of squalene epoxidase, (e azoles, which inhibit C14α-demethylase, and (f azasterols, which inhibit Δ24(25-sterol methyltransferase (SMT. Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures, and their effects on protozoan structural organization (as evaluted by light and electron microscopy and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take

  17. Arabidopsis Acetyl-Amido Synthetase GH3.5 Involvement in Camalexin Biosynthesis through Conjugation of Indole-3-Carboxylic Acid and Cysteine and Upregulation of Camalexin Biosynthesis Genes

    Institute of Scientific and Technical Information of China (English)

    Mu-Yang Wang; Xue-Ting Liu; Ying Chen; Xiao-Jing Xu; Biao Yu; Shu-Qun Zhang; Qun Li; Zu-Hua He

    2012-01-01

    Camalexin (3-thiazol-2'-yl-indole) is the major phytoalexin found in Arabidopsis thaliana.Several key intermediates and corresponding enzymes have been identified in camalexin biosynthesis through mutant screening and biochemical experiments.Camalexin is formed when indole-3-acetonitrile (IAN)is catalyzed by the cytochrome P450 monooxygenase CYP71A13.Here,we demonstrate that the Arabidopsis GH3.5 protein,a multifunctional acetyl-amido synthetase,is involved in camalexin biosynthesis via conjugating indole-3-carboxylic acid (ICA) and cysteine (Cys) and regulating camalexin biosynthesis genes.Camalexin levels were increased in the activation-tagged mutant gh3.5-1D in both Col-0 and cyp71A13-2 mutant backgrounds after pathogen infection.The recombinant GH3.5 protein catalyzed the conjugation of ICA and Cys to form a possible intermediate indole-3-acyl-cysteinate (ICA(Cys)) in vitro.In support of the in vitro reaction,feeding with ICA and Cys increased camalexin levels in Col-0 and gh3.5-1D.Dihydrocamalexic acid (DHCA),the precursor of camalexin and the substrate for PAD3,was accumulated in gh3.5-1Dlpad3-1,suggesting that ICA(Cys) could be an additional precursor of DHCA for camalexin biosynthesis.Furthermore,expression of the major camalexin biosynthesis genes CYP79B2,CYP71A12,CYP71A13 and PAD3 was strongly induced in gh3.5-1D.Our study suggests that GH3.5 is involved in camalexin biosynthesis through direct catalyzation of the formation of ICA(Cys),and upregulation of the major biosynthetic pathway genes.

  18. Dietary Polyunsaturated Fatty Acids and Inflammation: The Role of Phospholipid Biosynthesis

    OpenAIRE

    Sordillo, Lorraine M.; William Raphael

    2013-01-01

    The composition of fatty acids in the diets of both human and domestic animal species can regulate inflammation through the biosynthesis of potent lipid mediators. The substrates for lipid mediator biosynthesis are derived primarily from membrane phospholipids and reflect dietary fatty acid intake. Inflammation can be exacerbated with intake of certain dietary fatty acids, such as some ω-6 polyunsaturated fatty acids (PUFA), and subsequent incorporation into membrane phospholipids. Inflammati...

  19. EXPRESSED PROTEIN LIGATION. A NEW TOOL FOR THE BIOSYNTHESIS OF CYCLIC POLYPEPTIDES

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, R; Camarero, J A

    2004-11-11

    The present paper reviews the use of expressed protein ligation for the biosynthesis of backbone cyclic polypeptides. This general method allows the in vivo and in vitro biosynthesis of cyclic polypeptides using recombinant DNA expression techniques. Biosynthetic access to backbone cyclic peptides opens the possibility to generate cell-based combinatorial libraries that can be screened inside living cells for their ability to attenuate or inhibit cellular processes.

  20. Expanding the landscape of diterpene structural diversity by stereochemically controlled combinatorial biosynthesis

    DEFF Research Database (Denmark)

    Andersen-Ranberg, Johan; Kongstad, Kenneth Thermann; Nielsen, Morten Thrane;

    2016-01-01

    Plant derived diterpenoids are relevant as pharmaceuticals, food additives and fragrances, yet a broader industrial utilization of these bioproducts is limited due to their low natural abundance and high structural complexity. Mimicking the modularity of diterpene biosynthesis in plants, we...... constructed 51 functional diterpene synthase combinations, 41 of which were “new-to-nature”. Here, we demonstrate stereoselective biosynthesis in Nicotiana benthamiana of 47 diterpene skeletons including natural variants and novel enantiomeric or diastereomeric counterparts. Scalable biotechnological...

  1. Properties of Streptomyces fradiae Mutants Blocked in Biosynthesis of the Macrolide Antibiotic Tylosin

    OpenAIRE

    Baltz, Richard H; Seno, Eugene T.

    1981-01-01

    We isolated numerous mutants of Streptomyces fradiae blocked in tylosin biosynthesis after N-methyl-N′-nitro-N-nitrosoguanidine mutagenesis. These mutants were classified into nine groups, based upon the tylosin-like compounds produced and upon cofermentation analyses. More than 80% of the mutants isolated produced no tylosin-like compounds, and the majority of these were blocked only in the formation of tylactone. Four classes of mutants blocked in the biosynthesis or addition of tylosin sug...

  2. Effect of seed pickling without pesticides on the growth of Penicillium expansum and patulin biosynthesis

    Directory of Open Access Journals (Sweden)

    Teresa Florianowicz

    2014-08-01

    Full Text Available The effect of seed pickling without pesticides recommended by the Research Institute of Vegetable Crops in Skierniewice in the method of intensive environment-friendly cultivation on the growth and patulin biosynthesis of patulinogenous microfungus Penicillim expansum, was investigated. A complete inhibition of patulin biosynthesis at 6% and no growth at 8% concentration of the dressing in in vitro conditions was revealed.

  3. The chemical synthesis of porphobilinogen an important intermediate of the biosynthesis of the "pigments of life"

    OpenAIRE

    Bobal, Pavel; Neier, Reinhard

    2007-01-01

    Porphobilinogen is the second dedicated intermediate in the biosynthesis of «pigments of life». Only very few alkylpyrroles have been isolated from natural sources so far. The absence of stabilising substituents confers to porphobilinogen a high reactivity. The chemical synthesis of porphobilinogen had to take its sensitivity into account. The published synthesis of this unusual pyrrole are reviewed. The synthetic strategies used are analysed and compared with the biosynthesis.

  4. Polyamine biosynthesis is critical for growth and differentiation of the pancreas.

    Science.gov (United States)

    Mastracci, Teresa L; Robertson, Morgan A; Mirmira, Raghavendra G; Anderson, Ryan M

    2015-08-24

    The pancreas, in most studied vertebrates, is a compound organ with both exocrine and endocrine functions. The exocrine compartment makes and secretes digestive enzymes, while the endocrine compartment, organized into islets of Langerhans, produces hormones that regulate blood glucose. High concentrations of polyamines, which are aliphatic amines, are reported in exocrine and endocrine cells, with insulin-producing β cells showing the highest concentrations. We utilized zebrafish as a model organism, together with pharmacological inhibition or genetic manipulation, to determine how polyamine biosynthesis functions in pancreatic organogenesis. We identified that inhibition of polyamine biosynthesis reduces exocrine pancreas and β cell mass, and that these reductions are at the level of differentiation. Moreover, we demonstrate that inhibition of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, phenocopies inhibition or knockdown of the enzyme deoxyhypusine synthase (DHS). These data identify that the pancreatic requirement for polyamine biosynthesis is largely mediated through a requirement for spermidine for the downstream posttranslational modification of eIF5A by its enzymatic activator DHS, which in turn impacts mRNA translation. Altogether, we have uncovered a role for polyamine biosynthesis in pancreatic organogenesis and identified that it may be possible to exploit polyamine biosynthesis to manipulate pancreatic cell differentiation.

  5. Aerobic conditions increase isoprenoid biosynthesis pathway gene expression levels for carotenoid production in Enterococcus gilvus.

    Science.gov (United States)

    Hagi, Tatsuro; Kobayashi, Miho; Nomura, Masaru

    2015-06-01

    Some lactic acid bacteria that harbour carotenoid biosynthesis genes (crtNM) can produce carotenoids. Although aerobic conditions can increase carotenoid production and crtNM expression levels, their effects on the pathways that synthesize carotenoid precursors such as mevalonate and isoprene are not completely understood. In this study, we investigated whether aerobic conditions affected gene expression levels involved in the isoprenoid biosynthesis pathway that includes the mevalonate and isoprene biosynthesis pathways in Enterococcus gilvus using real-time quantitative reverse transcription PCR. NADH oxidase (nox) and superoxide dismutase (sod) gene expression levels were investigated as controls for aerobic conditions. The expression levels of nox and sod under aerobic conditions were 7.2- and 8.0-fold higher, respectively, than those under anaerobic conditions. Aerobic conditions concomitantly increased the expression levels of crtNM carotenoid biosynthesis genes. HMG-CoA synthase gene expression levels in the mevalonate pathway were only slightly increased under aerobic conditions, whereas the expression levels of HMG-CoA reductase and five other genes in the isoprene biosynthesis pathways were 1.2-2.3-fold higher than those under anaerobic conditions. These results demonstrated that aerobic conditions could increase the expression levels of genes involved in the isoprenoid biosynthesis pathway via mevalonate in E. gilvus.

  6. Control of triacylglycerol biosynthesis in plants. Technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-31

    Seeds of most species of the Umbelliferae (Apiaciae), Araliaceae, and Garryaceae families are characterized by their high content of the unusual C{sub 18} monounsaturated fatty acid petroselinic acid (18:l{Delta}{sup 6cis}). Prior to a recent report of this lab, little was known of the biosynthetic origin of the cis{Delta}{sup 6} double bond of petroselinic acid. Such knowledge may be of both biochemical and biotechnological significance. Because petroselinic acid is potentially the product of a novel desaturase, information regarding its synthesis may contribute to an understanding of fatty acid desaturation mechanisms in plants. Through chemical cleavage at its double bond, petroselinic acid can be used as a precursor of lauric acid (12:0), a component of detergents and surfactants, and adipic acid (6:0 dicarboxylic), the monomeric component of nylon 6,6. Therefore, the development of an agronomic source of an oil rich in petroselinic acid is of biotechnological interest. As such, studies of petroselinic acid biosynthesis may provide basic information required for any attempt to genetically engineer the production and accumulation of this fatty acid in an existing oilseed.

  7. Linking chlorophyll biosynthesis to a dynamic plastoquinone pool.

    Science.gov (United States)

    Steccanella, Verdiana; Hansson, Mats; Jensen, Poul Erik

    2015-12-01

    Chlorophylls are essential cofactors in photosynthesis. All steps in the chlorophyll pathway are well characterized except for the cyclase reaction in which the fifth ring of the chlorophyll molecule is formed during conversion of Mg-protoporphyrin IX monomethyl ester into Protochlorophyllide. The only subunit of the cyclase identified so far, is AcsF (Xantha-l in barley and Chl27 in Arabidopsis). This subunit contains a typical consensus di-iron-binding sequence and belongs to a subgroup of di-iron proteins, such as the plastid terminal oxidase (PTOX) in the chloroplast and the alternative oxidase (AOX) found in mitochondria. In order to complete the catalytic cycle, the irons of these proteins need to be reduced from Fe(3+) to Fe(2+) and either a reductase or another form of reductant is required. It has been reported that the alternative oxidase (AOX) and the plastid terminal oxidase (PTOX) utilize the di-iron center to oxidise ubiquinol and plastoquinol, respectively. In this paper, we have used a specific inhibitor of di-iron proteins as well as Arabidopsis and barley mutants affected in regulation of photosynthetic electron flow, to show that the cyclase step indeed is directly coupled to the plastoquinone pool. Thus, plastoquinol might act as an electron donor for the cyclase reaction and thereby fulfil the role of a cyclase reductase. That would provide a functional connection between the redox status of the thylakoids and the biosynthesis of chlorophyll.

  8. Biosynthesis of the defensive alkaloid cicindeloine in Stenus solutus beetles

    Science.gov (United States)

    Schierling, Andreas; Dettner, Konrad; Schmidt, Jürgen; Seifert, Karlheinz

    2012-08-01

    To protect themselves from predation and microorganismic infestation, rove beetles of the genus Stenus produce and store bioactive alkaloids like stenusine, 3-(2-methyl-1-butenyl)pyridine, and cicindeloine in their pygidial glands. The biosynthesis of stenusine and 3-(2-methyl-1-butenyl)pyridine was previously investigated in Stenus bimaculatus and Stenus similis, respectively. Both molecules follow the same biosynthetic pathway, where the N-heterocyclic ring is derived from l-lysine and the side chain from l-isoleucine. The different alkaloids are finally obtained by slight modifications of shared precursor molecules. The piperideine alkaloid cicindeloine occurs as a main compound additionally to ( E)-3-(2-methyl-1-butenyl)pyridine and traces of stenusine in the pygidial gland secretion of Stenus cicindeloides and Stenus solutus. Feeding of S. solutus beetles with [D,15N]-labeled amino acids followed by GC/MS analysis techniques showed that cicindeloine is synthesized via the identical pathway and precursor molecules as the other two defensive alkaloids.

  9. Menaquinone biosynthesis potentiates haem toxicity in Staphylococcus aureus.

    Science.gov (United States)

    Wakeman, Catherine A; Hammer, Neal D; Stauff, Devin L; Attia, Ahmed S; Anzaldi, Laura L; Dikalov, Sergey I; Calcutt, M Wade; Skaar, Eric P

    2012-12-01

    Staphylococcus aureus is a pathogen that infects multiple anatomical sites leading to a diverse array of diseases. Although vertebrates can restrict the growth of invading pathogens by sequestering iron within haem, S. aureus surmounts this challenge by employing high-affinity haem uptake systems. However, the presence of excess haem is highly toxic, necessitating tight regulation of haem levels. To overcome haem stress, S. aureus expresses the detoxification system HrtAB. In this work, a transposon screen was performed in the background of a haem-susceptible, HrtAB-deficient S. aureus strain to identify the substrate transported by this putative pump and the source of haem toxicity. While a recent report indicates that HrtAB exports haem itself, the haem-resistant mutants uncovered by the transposon selection enabled us to elucidate the cellular factors contributing to haem toxicity. All mutants identified in this screen inactivated the menaquinone (MK) biosynthesis pathway. Deletion of the final steps of this pathway revealed that quinone molecules localizing to the cell membrane potentiate haem-associated superoxide production and subsequent oxidative damage. These data suggest a model in which membrane-associated haem and quinone molecules form a redox cycle that continuously generates semiquinones and reduced haem, both of which react with atmospheric oxygen to produce superoxide.

  10. Facile biosynthesis, separation and conjugation of gold nanoparticles to doxorubicin

    Science.gov (United States)

    Kumar, S. Anil; Peter, Yves-Alain; Nadeau, Jay L.

    2008-12-01

    Particle shape and size determine the physicochemical and optoelectronic properties of nanoscale materials, including optical absorption, fluorescence, and electric and magnetic moments. It is thus desirable to be able to synthesize and separate various particle shapes and sizes. Biosynthesis using microorganisms has emerged as a more ecologically friendly, simpler, and more reproducible alternative to chemical synthesis of metal and semiconductor nanoparticles, allowing the generation of rare forms such as triangles. Here we show that the plant pathogenic fungus Helminthosporum solani, when incubated with an aqueous solution of chloroaurate ions, produces a diverse mixture of extracellular gold nanocrystals in the size range from 2 to 70 nm. A plurality are polydisperse spheres, but a significant number are homogeneously sized rods, triangles, pentagons, pyramids, and stars. The particles can be separated according to their size and shape by using a sucrose density gradient in a tabletop microcentrifuge, a novel and facile approach to nanocrystal purification. Conjugation to biomolecules can be performed without further processing, as illustrated with the smallest fraction of particles which were conjugated to the anti-cancer drug doxorubicin (Dox) and taken up readily into HEK293 cells. The cytotoxicity of the conjugates was comparable to that of an equivalent concentration of Dox.

  11. Sodium Acetate Stimulates PHB Biosynthesis in Synechocystis sp. PCC 6803

    Institute of Scientific and Technical Information of China (English)

    吴桂芳; 鲍恬; 沈忠耀; 吴庆余

    2002-01-01

    Synechocystis sp. PCC 6803 cell growth and poly-β-hydroxybutyrate (PHB) biosynthesis were studied in the presence of sodium acetate (NaAc). For nitrogen-sufficient conditions, 15 -mmol/L NaAc improved the PHB content up to 9.9% (w/w) while for nitrogen-starved conditions, the PHB content was up to 15.2% (w/w). NaAc at levels below 20 -mmol/L promoted cell growth in the first six days, but the growth slowed on the seventh day when the NaAc concentration exceeded 15 -mmol/L. The PHB content in the final biomass reached 11.0% of the dry cellular weight in the presence of 20 -mmol/L NaAc. Two adjacent open reading frames (ORFs) in the genome of Synechocystis sp. PCC 6803, slr1993 and slr1994, were assigned to phbA and phbB, respectively, while the phbC gene was found to be far from these genes. This may account for the low expression of PHB in cyanobacteria.

  12. CAN LIGNOCELLULOSE BIOSYNTHESIS BE THE KEY TO ITS ECONOMICAL DECONSTRUCTION?

    Directory of Open Access Journals (Sweden)

    Lucian A. Lucia

    2010-05-01

    Full Text Available It is ironic to think that the venerable pulp and paper industry is now considering ways to degrade cellulose. This notion can be understood as a way that the industry can face a protracted downturn in profitability and ever-mounting socio-economic pressures to enhance the efficiency of biofuels production. Many approaches have been recently taken to deconstruct cellulosic biomass, but this Editorial explores one key that may start to explain the increasing momentum in the biofuels community – biotechnology. Two approaches appear to be possible as scientists search for an effective way to unzip cellulose to its key constituents through the use of biotechnology. On the one hand, there are efforts to re-engineer the chemical composition of the tree, rendering it more digestible by enzymes and decreasing the need for mechanical or chemical pretreatment. On the other hand, what we are learning about lignocellulose biosynthesis can be of potential help in designing more efficient systems to essentially reverse that process.

  13. Biosynthesis and biological functions of terpenoids in plants.

    Science.gov (United States)

    Tholl, Dorothea

    2015-01-01

    Terpenoids (isoprenoids) represent the largest and most diverse class of chemicals among the myriad compounds produced by plants. Plants employ terpenoid metabolites for a variety of basic functions in growth and development but use the majority of terpenoids for more specialized chemical interactions and protection in the abiotic and biotic environment. Traditionally, plant-based terpenoids have been used by humans in the food, pharmaceutical, and chemical industries, and more recently have been exploited in the development of biofuel products. Genomic resources and emerging tools in synthetic biology facilitate the metabolic engineering of high-value terpenoid products in plants and microbes. Moreover, the ecological importance of terpenoids has gained increased attention to develop strategies for sustainable pest control and abiotic stress protection. Together, these efforts require a continuous growth in knowledge of the complex metabolic and molecular regulatory networks in terpenoid biosynthesis. This chapter gives an overview and highlights recent advances in our understanding of the organization, regulation, and diversification of core and specialized terpenoid metabolic pathways, and addresses the most important functions of volatile and nonvolatile terpenoid specialized metabolites in plants.

  14. Combinatorial biosynthesis of flavones and flavonols in Escherichia coli.

    Science.gov (United States)

    Miyahisa, Ikuo; Funa, Nobutaka; Ohnishi, Yasuo; Martens, Stefan; Moriguchi, Takaya; Horinouchi, Sueharu

    2006-06-01

    (2S)-Flavanones (naringenin and pinocembrin) are key intermediates in the flavonoid biosynthetic pathway in plants. Recombinant Escherichia coli cells containing four genes for a phenylalanine ammonia-lyase, cinnamate/coumarate:CoA ligase, chalcone synthase, and chalcone isomerase, in addition to the acetyl-CoA carboxylase, have been established for efficient production of (2S)-naringenin from tyrosine and (2S)-pinocembrin from phenylalanine. Further introduction of the flavone synthase I gene from Petroselinum crispum under the control of the T7 promoter and the synthetic ribosome-binding sequence in pACYCDuet-1 caused the E. coli cells to produce flavones: apigenin (13 mg/l) from tyrosine and chrysin (9.4 mg/l) from phenylalanine. Introduction into the E. coli cells of the flavanone 3beta-hydroxylase and flavonol synthase genes from the plant Citrus species led to production of flavonols: kaempferol (15.1 mg/l) from tyrosine and galangin (1.1 mg/l) from phenylalanine. The combinatorial biosynthesis of the flavones and flavonols in E. coli is promising for the construction of a library of various flavonoid compounds and un-natural flavonoids in bacteria.

  15. Alterations in renal heme biosynthesis during metal nephrotoxicity.

    Science.gov (United States)

    Oskarsson, A; Fowler, B A

    1987-01-01

    The regulation of the heme biosynthetic pathway in the kidney by various metals has been reviewed. In addition, a study on the effects of lead on renal heme biosynthesis after acute treatment of rats has been reported. Chronic low-level lead exposure in rats results in relatively small effects on renal heme biosynthetic pathway enzymes. After acute treatment of rats with lead, no effects on ALAD or UROS and mild, transitory effects on ALAS and ferrochelatase are observed. The intracellular binding of lead within intranuclear inclusion bodies in the proximal tubule cells and to high-affinity cytosolic lead-binding proteins probably protects sensitive subcellular systems, such as the heme pathway, from lead toxicity. Chronic exposure to methyl mercury results in increased urinary excretion of uro- and coproporphyrins in rats, mediated via inhibition of ferrochelatase and UROS and stimulation of ALAS. A tissue-specific inhibition of ALAD occurs in the kidney after treatment of rats with indium. Acute treatment of rats with nickel, platinum, tin, antimony, bismuth, and cobalt results in induction of heme oxygenase, followed by decreased microsomal heme content and ALAS stimulation in the kidney.

  16. Biosynthesis of Panaxynol and Panaxydol in Panax ginseng

    Directory of Open Access Journals (Sweden)

    Rosa M. Cusidó

    2013-07-01

    Full Text Available The natural formation of the bioactive C17-polyacetylenes (−-(R-panaxynol and panaxydol was analyzed by 13C-labeling experiments. For this purpose, plants of Panax ginseng were supplied with 13CO2 under field conditions or, alternatively, sterile root cultures of P. ginseng were supplemented with [U-13C6]glucose. The polyynes were isolated from the labeled roots or hairy root cultures, respectively, and analyzed by quantitative NMR spectroscopy. The same mixtures of eight doubly 13C-labeled isotopologues and one single labeled isotopologue were observed in the C17-polyacetylenes obtained from the two experiments. The polyketide-type labeling pattern is in line with the biosynthetic origin of the compounds via decarboxylation of fatty acids, probably of crepenynic acid. The 13C-study now provides experimental evidence for the biosynthesis of panaxynol and related polyacetylenes in P. ginseng under in planta conditions as well as in root cultures. The data also show that 13CO2 experiments under field conditions are useful to elucidate the biosynthetic pathways of metabolites, including those from roots.

  17. Tryptophan tryptophylquinone biosynthesis: a radical approach to posttranslational modification.

    Science.gov (United States)

    Davidson, Victor L; Liu, Aimin

    2012-11-01

    Protein-derived cofactors are formed by irreversible covalent posttranslational modification of amino acid residues. An example is tryptophan tryptophylquinone (TTQ) found in the enzyme methylamine dehydrogenase (MADH). TTQ biosynthesis requires the cross-linking of the indole rings of two Trp residues and the insertion of two oxygen atoms onto adjacent carbons of one of the indole rings. The diheme enzyme MauG catalyzes the completion of TTQ within a precursor protein of MADH. The preMADH substrate contains a single hydroxyl group on one of the tryptophans and no crosslink. MauG catalyzes a six-electron oxidation that completes TTQ assembly and generates fully active MADH. These oxidation reactions proceed via a high valent bis-Fe(IV) state in which one heme is present as Fe(IV)=O and the other is Fe(IV) with both axial heme ligands provided by amino acid side chains. The crystal structure of MauG in complex with preMADH revealed that catalysis does not involve direct contact between the hemes of MauG and the protein substrate. Rather it is accomplished through long-range electron transfer, which presumably generates radical intermediates. Kinetic, spectrophotometric, and site-directed mutagenesis studies are beginning to elucidate how the MauG protein controls the reactivity of the hemes and mediates the long range electron/radical transfer required for catalysis. This article is part of a Special Issue entitled: Radical SAM enzymes and Radical Enzymology.

  18. Genetics, Biosynthesis, Structure, and Mode of Action of Lantibiotics

    Science.gov (United States)

    Kuipers, Anneke; Rink, Rick; Moll, Gert N.

    Lantibiotics are lanthionine-containing peptide antibiotics. They are characterized by having meso-lanthionine(s) and/or β-methyllanthionine(s) or both. These intramolecular monosulfide cross-links render the peptide resistant against breakdown by peptidases. Moreover, in several cases, the (methyl)lanthionines are essential for interaction with the so-called docking molecule lipid II. The best known lantibiotic, nisin, highly effectively inhibits growth of target cells via two mechanisms: (1) abduction of the cell wall precursor lipid II from the septum and (2) formation of pores composed of lipid II and nisin. (Methyl)lanthionines result from two enzyme-catalyzed posttranslational modifications: dehydration of serines/threonines and coupling of the resulting dehydro amino acids to cysteines. Besides the localization of the thioether bridges and dehydro amino acids in the lantibiotics, also the three-dimensional structure of some lantibiotics has been resolved by NMR. Genes encoding proteins involved in the biosynthesis of lantibiotics are present in clusters and may comprise combinations of the following genes in varying order: a structural gene that encodes a leader peptide and the lantibiotic propeptide, modification enzyme(s), a transporter responsible for the export of the lantibiotic and in some cases for cleavage of the leader peptide, a leader peptidase, a so-called immunity protein involved in self-protection of the host cell, components of a transporter also involved in self-protection, and two components of an autoinduction system.

  19. Metabolic Engineering of Tropane Alkaloid Biosynthesis in Plants

    Institute of Scientific and Technical Information of China (English)

    Lei ZHANG; Guo-Yin KAI; Bei-Bei LU; Han-Ming ZHANG; Ke-Xuan TANG; Ji-Hong JIANG; Wan-Sheng CHEN

    2005-01-01

    Over the past decade, the evolving commercial importance of so-called plant secondary metabolites has resulted in a great interest in secondary metabolism and, particularly, in the possibilities to enhance the yield of fine metabolites by means of genetic engineering. Plant alkaloids, which constitute one of the largest groups of natural products, provide many pharmacologically active compounds. Several genes in the tropane alkaloids biosynthesis pathways have been cloned, making the metabolic engineering of these alkaloids possible. The content of the target chemical scopolamine could be significantly increased by various approaches, such as introducing genes encoding the key biosynthetic enzymes or genes encoding regulatory proteins to overcome the specific rate-limiting steps. In addition, antisense genes have been used to block competitive pathways. These investigations have opened up new, promising perspectives for increased production in plants or plant cell culture. Recent achievements have been made in the metabolic engineering of plant tropane alkaloids and some new powerful strategies are reviewed in the present paper.

  20. Production and transcriptional regulation of proanthocyanidin biosynthesis in forage legumes.

    Science.gov (United States)

    Zhou, Meiliang; Wei, Li; Sun, Zhanmin; Gao, Lihua; Meng, Yu; Tang, Yixiong; Wu, Yanmin

    2015-05-01

    Proanthocyanidins (PA), also known as condensed tannins, contribute to important forage legumes traits including disease resistance and forage quality. PA in forage plants has both positive and negative effects on feed digestibility and animal performance. The analytical methods and their applicability in measuring the contents of PA in forage plants are essential to studies on their nutritional effects. In spite of important breakthroughs in our understanding of the PA biosynthesis, important questions still remain to be answered such as the PA polymerization and transport. Recent advances in the understanding of transcription factor-mediated gene regulation mechanisms in anthocyanin and PA biosynthetic pathway in model plants suggest new approaches for the metabolic engineering of PA in forage plants. The present review will attempt to present the state-of-the-art of research in these areas and provide an update on the production and metabolic engineering of PA in forage plants. We hope that this will contribute to a better understanding of the ways in which PA production to manipulate the content of PA for beneficial effects in forage plants.

  1. Engineering of glucosinolate biosynthesis: candidate gene identification and validation.

    Science.gov (United States)

    Møldrup, Morten E; Salomonsen, Bo; Halkier, Barbara A

    2012-01-01

    The diverse biological roles of glucosinolates as plant defense metabolites and anticancer compounds have spurred a strong interest in their biosynthetic pathways. Since the completion of the Arabidopsis genome, functional genomics approaches have enabled significant progress on the elucidation of glucosinolate biosynthesis, although in planta validation of candidate gene function often is hampered by time-consuming generation of knockout and overexpression lines in Arabidopsis. To better exploit the increasing amount of data available from genomic sequencing, microarray database and RNAseq, time-efficient methods for identification and validation of candidate genes are needed. This chapter covers the methodology we are using for gene discovery in glucosinolate engineering, namely, guilt-by-association-based in silico methods and fast proof-of-function screens by transient expression in Nicotiana benthamiana. Moreover, the lessons learned in the rapid, transient tobacco system are readily translated to our robust, versatile yeast expression platform, where additional genes critical for large-scale microbial production of glucosinolates can be identified. We anticipate that the methodology presented here will be beneficial to elucidate and engineer other plant biosynthetic pathways.

  2. Genome-Wide Screening of Genes Required for Glycosylphosphatidylinositol Biosynthesis.

    Directory of Open Access Journals (Sweden)

    Yao Rong

    Full Text Available Glycosylphosphatidylinositol (GPI is synthesized and transferred to proteins in the endoplasmic reticulum (ER. GPI-anchored proteins are then transported from the ER to the plasma membrane through the Golgi apparatus. To date, at least 17 steps have been identified to be required for the GPI biosynthetic pathway. Here, we aimed to establish a comprehensive screening method to identify genes involved in GPI biosynthesis using mammalian haploid screens. Human haploid cells were mutagenized by the integration of gene trap vectors into the genome. Mutagenized cells were then treated with a bacterial pore-forming toxin, aerolysin, which binds to GPI-anchored proteins for targeting to the cell membrane. Cells that showed low surface expression of CD59, a GPI-anchored protein, were further enriched for. Gene trap insertion sites in the non-selected population and in the enriched population were determined by deep sequencing. This screening enriched 23 gene regions among the 26 known GPI biosynthetic genes, which when mutated are expected to decrease the surface expression of GPI-anchored proteins. Our results indicate that the forward genetic approach using haploid cells is a useful and powerful technique to identify factors involved in phenotypes of interest.

  3. Modulation of Phytoalexin Biosynthesis in Engineered Plants for Disease Resistance

    Directory of Open Access Journals (Sweden)

    Sylvain Cordelier

    2013-07-01

    Full Text Available Phytoalexins are antimicrobial substances of low molecular weight produced by plants in response to infection or stress, which form part of their active defense mechanisms. Starting in the 1950’s, research on phytoalexins has begun with biochemistry and bio-organic chemistry, resulting in the determination of their structure, their biological activity as well as mechanisms of their synthesis and their catabolism by microorganisms. Elucidation of the biosynthesis of numerous phytoalexins has permitted the use of molecular biology tools for the exploration of the genes encoding enzymes of their synthesis pathways and their regulators. Genetic manipulation of phytoalexins has been investigated to increase the disease resistance of plants. The first example of a disease resistance resulting from foreign phytoalexin expression in a novel plant has concerned a phytoalexin from grapevine which was transferred to tobacco. Transformations were then operated to investigate the potential of other phytoalexin biosynthetic genes to confer resistance to pathogens. Unexpectedly, engineering phytoalexins for disease resistance in plants seem to have been limited to exploiting only a few phytoalexin biosynthetic genes, especially those encoding stilbenes and some isoflavonoids. Research has rather focused on indirect approaches which allow modulation of the accumulation of phytoalexin employing transcriptional regulators or components of upstream regulatory pathways. Genetic approaches using gain- or less-of functions in phytoalexin engineering together with modulation of phytoalexin accumulation through molecular engineering of plant hormones and defense-related marker and elicitor genes have been reviewed.

  4. Pathways and Subcellular Compartmentation of NAD Biosynthesis in Human Cells

    Science.gov (United States)

    Nikiforov, Andrey; Dölle, Christian; Niere, Marc; Ziegler, Mathias

    2011-01-01

    NAD is a vital redox carrier, and its degradation is a key element of important regulatory pathways. NAD-mediated functions are compartmentalized and have to be fueled by specific biosynthetic routes. However, little is known about the different pathways, their subcellular distribution, and regulation in human cells. In particular, the route(s) to generate mitochondrial NAD, the largest subcellular pool, is still unknown. To visualize organellar NAD changes in cells, we targeted poly(ADP-ribose) polymerase activity into the mitochondrial matrix. This activity synthesized immunodetectable poly(ADP-ribose) depending on mitochondrial NAD availability. Based on this novel detector system, detailed subcellular enzyme localizations, and pharmacological inhibitors, we identified extracellular NAD precursors, their cytosolic conversions, and the pathway of mitochondrial NAD generation. Our results demonstrate that, besides nicotinamide and nicotinic acid, only the corresponding nucleosides readily enter the cells. Nucleotides (e.g. NAD and NMN) undergo extracellular degradation resulting in the formation of permeable precursors. These precursors can all be converted to cytosolic and mitochondrial NAD. For mitochondrial NAD synthesis, precursors are converted to NMN in the cytosol. When taken up into the organelles, NMN (together with ATP) serves as substrate of NMNAT3 to form NAD. NMNAT3 was conclusively localized to the mitochondrial matrix and is the only known enzyme of NAD synthesis residing within these organelles. We thus present a comprehensive dissection of mammalian NAD biosynthesis, the groundwork to understand regulation of NAD-mediated processes, and the organismal homeostasis of this fundamental molecule. PMID:21504897

  5. Another brick in the cell wall: biosynthesis dependent growth model.

    Science.gov (United States)

    Barbacci, Adelin; Lahaye, Marc; Magnenet, Vincent

    2013-01-01

    Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i) a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii) new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper.

  6. Another brick in the cell wall: biosynthesis dependent growth model.

    Directory of Open Access Journals (Sweden)

    Adelin Barbacci

    Full Text Available Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper.

  7. Lysophospholipid acyltransferases and eicosanoid biosynthesis in zebrafish myeloid cells.

    Science.gov (United States)

    Zarini, Simona; Hankin, Joseph A; Murphy, Robert C; Gijón, Miguel A

    2014-10-01

    Eicosanoids derived from the enzymatic oxidation of arachidonic acid play important roles in a large number of physiological and pathological processes in humans. Many animal and cellular models have been used to investigate the intricate mechanisms regulating their biosynthesis and actions. Zebrafish is a widely used model to study the embryonic development of vertebrates. It expresses homologs of the key enzymes involved in eicosanoid production, and eicosanoids have been detected in extracts from adult or embryonic fish. In this study we prepared cell suspensions from kidney marrow, the main hematopoietic organ in fish. Upon stimulation with calcium ionophore, these cells produced eicosanoids including PGE2, LTB4, 5-HETE and, most abundantly, 12-HETE. They also produced small amounts of LTB5 derived from eicosapentaenoic acid. These eicosanoids were also produced in kidney marrow cells stimulated with ATP, and this production was greatly enhanced by preincubation with thimerosal, an inhibitor of arachidonate reacylation into phospholipids. Microsomes from these cells exhibited acyltransferase activities consistent with expression of MBOAT5/LPCAT3 and MBOAT7/LPIAT1, the main arachidonoyl-CoA:lysophospholipid acyltransferases. In summary, this work introduces a new cellular model to study the regulation of eicosanoid production through a phospholipid deacylation-reacylation cycle from a well-established, versatile vertebrate model species.

  8. Ceramide biosynthesis in keratinocyte and its role in skin function.

    Science.gov (United States)

    Mizutani, Yukiko; Mitsutake, Susumu; Tsuji, Kiyomi; Kihara, Akio; Igarashi, Yasuyuki

    2009-06-01

    The enucleate layer of the epidermis, i.e. the stratum corneum, is responsible for certain critical protective functions, such as epidermal permeability barrier function. Within the epidermal membrane lamella component, ceramides are the dominant lipid class by weight (over 50%) and exhibit the greatest molecular heterogeneity in terms of sphingoid base and fatty acid composition. It is now evermore important to understand how ceramide production and functions are controlled in the epidermis, since decreased epidermal ceramide content has been linked to water loss and barrier dysfunction. During the past several years, critical enzymes in ceramide biosynthesis have been identified, including ceramide synthases (CerS) and ceramide hydroxylase/desaturase. In this review, we describe the molecular heterogeneity of ceramides synthesized in the epidermis and their possible roles in epidermal permeability barrier functions. We also describe recent studies that identified the family of CerS (CerS1-CerS6) in mammals. We further focus on the roles of specific isoforms of these enzymes in synthesizing the epidermal ceramides, especially in relation to chain-length specificity. In addition, we provide experimental information, including our recent findings, as to how applying ceramide or ceramide-containing substances to skin, orally or directly, can benefit skin health.

  9. Biosynthesis of thiophenes in cell cultures of Tagetes patula

    Energy Technology Data Exchange (ETDEWEB)

    Helsper, H.; Blaakmeer, A. (Research Institute Ital, Wageningen (Netherlands))

    1989-04-01

    Cell cultures of Tagetes patula incorporate {sup 35}S-label from methionine, cysteine, sulfide and sulfate into thiophenes, a group of heterocyclic biocides. In time course studies up to 4% of the total {sup 35}S-label from ({sup 35}S) sulfate was incorporated into thiophenes within 24 hours. The bulk of the radioactivity (>80%) in thiophenes was observed in 5-(4-hydroxy-1-butinyl)-2,2{prime}-bithiophene (BBTOH) while the rest was in 5-(4-acetoxy-1-butinyl)-2-2{prime} -bithiophene (BBTOAc) and 5-(but-3-ene-1-ynyl)-2,2{prime}-bithiophene. Pulse-chase experiments, involving a 24 h-pulse with ({sup 35}S) sulfate, showed a constant level of radioactivity in BBT during the chase period while there was a shift in {sup 35}S-label from BBTOH to BBTOAc. Also, the specific activity of BBT was always lower than that of the other two while the specific activity of BBTOH was higher than that of BBTOAc. These results indicate that (a) BBT is not an obligatory intermediate in the biosynthesis of BBTOH and BBTOAc and (b) BBTOH may be the precursor for BBTOAc.

  10. Plant Glutathione Biosynthesis: Diversity in Biochemical Regulation and Reaction Products

    Directory of Open Access Journals (Sweden)

    Ashley eGalant

    2011-09-01

    Full Text Available In plants, exposure to temperature extremes, heavy metal-contaminated soils, drought, air pollutants, and pathogens results in the generation of reactive oxygen species that alter the intracellular redox environment, which in turn influences signaling pathways and cell fate. As part of their response to these stresses, plants produce glutathione. Glutathione acts as an antioxidant by quenching reactive oxygen species, and is involved in the ascorbate-glutathione cycle that eliminates damaging peroxides. Plants also use glutathione for the detoxification of xenobiotics, herbicides, air pollutants (sulfur dioxide and ozone, and toxic heavy metals. Two enzymes catalyze glutathione synthesis: glutamate-cysteine ligase (GCL, and glutathione synthetase (GS. Glutathione is a ubiquitous protective compound in plants, but the structural and functional details of the proteins that synthesize it, as well as the potential biochemical mechanisms of their regulation, have only begun to be explored. As discussed here, the core reactions of glutathione synthesis are conserved across various organisms, but plants have diversified both the regulatory mechanisms that control its synthesis and the range of products derived from this pathway. Understanding the molecular basis of glutathione biosynthesis and its regulation will expand our knowledge of this component in the plant stress response network.

  11. Plant glutathione biosynthesis: diversity in biochemical regulation and reaction products.

    Science.gov (United States)

    Galant, Ashley; Preuss, Mary L; Cameron, Jeffrey C; Jez, Joseph M

    2011-01-01

    In plants, exposure to temperature extremes, heavy metal-contaminated soils, drought, air pollutants, and pathogens results in the generation of reactive oxygen species that alter the intracellular redox environment, which in turn influences signaling pathways and cell fate. As part of their response to these stresses, plants produce glutathione. Glutathione acts as an anti-oxidant by quenching reactive oxygen species, and is involved in the ascorbate-glutathione cycle that eliminates damaging peroxides. Plants also use glutathione for the detoxification of xenobiotics, herbicides, air pollutants (sulfur dioxide and ozone), and toxic heavy metals. Two enzymes catalyze glutathione synthesis: glutamate-cysteine ligase, and glutathione synthetase. Glutathione is a ubiquitous protective compound in plants, but the structural and functional details of the proteins that synthesize it, as well as the potential biochemical mechanisms of their regulation, have only begun to be explored. As discussed here, the core reactions of glutathione synthesis are conserved across various organisms, but plants have diversified both the regulatory mechanisms that control its synthesis and the range of products derived from this pathway. Understanding the molecular basis of glutathione biosynthesis and its regulation will expand our knowledge of this component in the plant stress response network.

  12. Polyketide folding in higher plants: biosynthesis of the phenylanthraquinone knipholone.

    Science.gov (United States)

    Bringmann, Gerhard; Noll, Torsten F; Gulder, Tanja; Dreyer, Michael; Grüne, Matthias; Moskau, Detlef

    2007-04-27

    The biosynthesis of knipholone, as an axially chiral phenylanthraquinone, in higher plants was examined by feeding experiments with [13C2]-labeled precursors. [13C2]-Acetate and advanced synthetic intermediates were fed to sterile cultures of Kniphofia pumila (Asphodelaceae), with subsequent NMR analysis on the isolated natural product involving 2D INADEQUATE and SELINQUATE experiments. Due to its uneven number of carbon atoms, and because of its uncertain decarboxylation site, the "northern" part of the molecule (i.e., the chrysophanol portion) might originate from four different cyclization modes. According to the labeling pattern of the product isolated after incorporation, this anthraquinone part of knipholone is formed by the so-called F folding mode (originally established for fungi). The acetophenone part of the molecule, which does not undergo a decarboxylation reaction, originates from four acetate units. The surprising lack of randomization of the intact [13C2] units in this "southern" part reveals the absence of a free symmetric intermediate as initially anticipated. This is in agreement with the intact incorporation of the "authentic" southern molecular portion, 4,6-dihydroxy-2-methoxyacetophenone, while the corresponding symmetrical candidate trihydroxyacetophenone was clearly not incorporated, showing that the O-methylation of the freshly cyclized tetraketide is the step that prevents symmetrization of the acetophenone.

  13. Biosynthesis of novel thermoplastic polythioesters by engineered Escherichia coli

    Science.gov (United States)

    Lütke-Eversloh, Tina; Fischer, Andreas; Remminghorst, Uwe; Kawada, Jumpei; Marchessault, Robert H.; Bögershausen, Ansgar; Kalwei, Martin; Eckert, Hellmut; Reichelt, Rudolf; Liu, Shuang-Jiang; Steinbüchel, Alexander

    2002-12-01

    The development of non-petrochemical sources for the plastics industry continues to progress as large multinationals focus on renewable resources to replace fossil carbon. Many bacteria are known to accumulate polyoxoesters as water-insoluble granules in the cytoplasm. The thermoplastic and/or elastomeric behaviour of these biodegradable polymers holds promise for the development of various technological applications. Here, we report the synthesis and characterization of microbial polythioesters (PTEs), a novel class of biopolymers of general technological relevance. Biosynthesis of PTE homopolymers was achieved using a recombinant strain of Escherichia coli that expressed a non-natural pathway consisting of a butyrate kinase, a phosphotransbutyrylase, and a PHA synthase. Different homopolymers were produced, consisting of either 3-mercaptopropionate, 3-mercaptobutyrate, or 3-mercaptovalerate repeating units, if the respective mercaptoalkanoic acids were provided as precursor substrates to the fermentative process. The PTEs contributed up to 30% (w/w) of the cellular dry weight and were identified as hydrophobic inclusions in the cytoplasm. The chemical and stereochemical homogeneity of the purified PTEs were identified by different methods, and the estimated physical properties were compared to the oxypolyester equivalents, revealing low crystalline order and, for the poly(3-mercaptopropionate) improved thermal stability. The ability to produce PTEs through a biosynthetic route opens up new avenues in the field of biomaterials.

  14. Systems biology approaches to understand natural products biosynthesis

    Directory of Open Access Journals (Sweden)

    Cuauhtemoc eLicona-Cassani

    2015-12-01

    Full Text Available Actinomycetes populate soils and aquatic sediments which impose biotic and abiotic challenges for their survival. As a result, actinomycetes metabolism and genomes have evolved to produce an overwhelming diversity of specialized molecules. Polyketides, non-ribosomal peptides, post-translationally modified peptides, lactams and terpenes are well known bioactive natural products with enormous industrial potential. Accessing such biological diversity has proven difficult due to the complex regulation of cellular metabolism in actinomycetes and to the sparse knowledge of their physiology. The past decade, however, has seen the development of omics technologies that have significantly contributed to our better understanding of their biology. Key observations have contributed towards a shift in the exploitation of actinomycetes biology, such as using their full genomic potential, activating entire pathways through key metabolic elicitors and pathway engineering to improve biosynthesis. Here, we review recent efforts devoted to achieving enhanced discovery, activation and manipulation of natural product biosynthetic pathways in model actinomycetes using genome-scale biological datasets.

  15. A comparative genomics study of genetic products potentially encoding ladderane lipid biosynthesis

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    Jetten Mike SM

    2009-02-01

    Full Text Available Abstract Background The fatty acids of anaerobic ammonium oxidizing (anammox bacteria contain linearly concatenated cyclobutane moieties, so far unique to biology. These moieties are under high ring strain and are synthesised by a presently unknown biosynthetic pathway. Results Gene clusters encoding enzymes of fatty acid biosynthesis in the anammox bacterium Kuenenia stuttgartiensis and 137 other organisms were analysed and compared in silico to gain further insight into the pathway of (ladderane fatty acid biosynthesis. In K. stuttgartiensis four large gene clusters encode fatty acid biosynthesis. Next to the regular enzyme complex needed for fatty acid biosynthesis (FASII, the presence of four putative S-adenosyl-methionine (SAM radical enzymes, two enzymes similar to phytoene desaturases and many divergent paralogues of β-ketoacyl-ACP synthase (fabF were unusual. Surprisingly, extensive synteny was observed with FASII gene clusters in the deltaproteobacterium Desulfotalea psychrophila. No ladderane lipids were detected in lipid extracts of this organism but we did find unusual polyunsaturated hydrocarbons (PUHC, not detected in K. stuttgartiensis. Conclusion We suggest that the unusual gene clusters of K. stuttgartiensis and D. psychrophila encode a novel pathway for anaerobic PUFA biosynthesis and that K. stuttgartiensis further processes PUFA into ladderane lipids, in similar fashion to the previously proposed route of ladderane lipid biosynthesis. However, the presence of divergent paralogues of fabF with radically different active site topologies may suggest an alternative pathway where ladderane moieties are synthesised externally and are recruited into the pathway of fatty acid biosynthesis. Reviewers This article was reviewed by Dr Michael Galperin (nominated by Prof E. Koonin, Dr Andrei Osterman and Dr Jeremy Selengut.

  16. Agrobacterium mediated transient gene silencing (AMTS in Stevia rebaudiana: insights into steviol glycoside biosynthesis pathway.

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    Praveen Guleria

    Full Text Available BACKGROUND: Steviol glycoside biosynthesis pathway has emerged as bifurcation from ent-kaurenoic acid, substrate of methyl erythritol phosphate pathway that also leads to gibberellin biosynthesis. However, the genetic regulation of steviol glycoside biosynthesis has not been studied. So, in present study RNA interference (RNAi based Agrobacterium mediated transient gene silencing (AMTS approach was followed. SrKA13H and three SrUGTs (SrUGT85C2, SrUGT74G1 and SrUGT76G1 genes encoding ent-kaurenoic acid-13 hydroxylase and three UDP glycosyltransferases of steviol glycoside biosynthesis pathway were silenced in Stevia rebaudiana to understand its molecular mechanism and association with gibberellins. METHODOLOGY/PRINCIPAL FINDINGS: RNAi mediated AMTS of SrKA13H and three SrUGTs has significantly reduced the expression of targeted endogenous genes as well as total steviol glycoside accumulation. While gibberellins (GA3 content was significantly enhanced on AMTS of SrUGT85C2 and SrKA13H. Silencing of SrKA13H and SrUGT85C2 was found to block the metabolite flux of steviol glycoside pathway and shifted it towards GA3 biosynthesis. Further, molecular docking of three SrUGT proteins has documented highest affinity of SrUGT76G1 for the substrates of alternate pathways synthesizing steviol glycosides. This could be a plausible reason for maximum reduction in steviol glycoside content on silencing of SrUGT76G1 than other genes. CONCLUSIONS: SrKA13H and SrUGT85C2 were identified as regulatory genes influencing carbon flux between steviol glycoside and gibberellin biosynthesis. This study has also documented the existence of alternate steviol glycoside biosynthesis route.

  17. Ectopic expression of MYB46 identifies transcriptional regulatory genes involved in secondary wall biosynthesis in Arabidopsis.

    Science.gov (United States)

    Ko, Jae-Heung; Kim, Won-Chan; Han, Kyung-Hwan

    2009-11-01

    MYB46 functions as a transcriptional switch that turns on the genes necessary for secondary wall biosynthesis. Elucidating the transcriptional regulatory network immediately downstream of MYB46 is crucial to our understanding of the molecular and biochemical processes involved in the biosynthesis and deposition of secondary walls in plants. To gain insights into MYB46-mediated transcriptional regulation, we first established an inducible secondary wall thickening system in Arabidopsis by expressing MYB46 under the control of dexamethasone-inducible promoter. Then, we used an ATH1 GeneChip microarray and Illumina digital gene expression system to obtain a series of transcriptome profiles with regard to the induction of secondary wall development. These analyses allowed us to identify a group of transcription factors whose expression coincided with or preceded the induction of secondary wall biosynthetic genes. A transient transcriptional activation assay was used to confirm the hierarchical relationships among the transcription factors in the network. The in vivo assay showed that MYB46 transcriptionally activates downstream target transcription factors, three of which (AtC3H14, MYB52 and MYB63) were shown to be able to activate secondary wall biosynthesis genes. AtC3H14 activated the transcription of all of the secondary wall biosynthesis genes tested, suggesting that AtC3H14 may be another master regulator of secondary wall biosynthesis. The transcription factors identified here may include direct activators of secondary wall biosynthesis genes. The present study discovered novel hierarchical relationships among the transcription factors involved in the transcriptional regulation of secondary wall biosynthesis, and generated several testable hypotheses.

  18. Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus

    DEFF Research Database (Denmark)

    Beck, Hans Christian

    2005-01-01

    Fatty acid biosynthesis by a mutant strain of Staphylococcus carnosus deficient in branched-chain amino acid aminotransferase (IlvE) activity was analysed. This mutant was unable to produce the appropriate branched-chain alpha-ketoacid precursors for branched-chain fatty acid biosynthesis from...... for 2-methylpropanoic acid production, revealing that the IlvE protein plays an important, but not essential role in the biosynthesis of branched-chain fatty acids and secondary metabolites in S. carnosus....

  19. WRKY Transcription Factors Involved in Activation of SA Biosynthesis Genes

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    Bol John F

    2011-05-01

    Full Text Available Abstract Background Increased defense against a variety of pathogens in plants is achieved through activation of a mechanism known as systemic acquired resistance (SAR. The broad-spectrum resistance brought about by SAR is mediated through salicylic acid (SA. An important step in SA biosynthesis in Arabidopsis is the conversion of chorismate to isochorismate through the action of isochorismate synthase, encoded by the ICS1 gene. Also AVRPPHB SUSCEPTIBLE 3 (PBS3 plays an important role in SA metabolism, as pbs3 mutants accumulate drastically reduced levels of SA-glucoside, a putative storage form of SA. Bioinformatics analysis previously performed by us identified WRKY28 and WRKY46 as possible regulators of ICS1 and PBS3. Results Expression studies with ICS1 promoter::β-glucuronidase (GUS genes in Arabidopsis thaliana protoplasts cotransfected with 35S::WRKY28 showed that over expression of WRKY28 resulted in a strong increase in GUS expression. Moreover, qRT-PCR analyses indicated that the endogenous ICS1 and PBS3 genes were highly expressed in protoplasts overexpressing WRKY28 or WRKY46, respectively. Electrophoretic mobility shift assays indentified potential WRKY28 binding sites in the ICS1 promoter, positioned -445 and -460 base pairs upstream of the transcription start site. Mutation of these sites in protoplast transactivation assays showed that these binding sites are functionally important for activation of the ICS1 promoter. Chromatin immunoprecipitation assays with haemagglutinin-epitope-tagged WRKY28 showed that the region of the ICS1 promoter containing the binding sites at -445 and -460 was highly enriched in the immunoprecipitated DNA. Conclusions The results obtained here confirm results from our multiple microarray co-expression analyses indicating that WRKY28 and WRKY46 are transcriptional activators of ICS1 and PBS3, respectively, and support this in silico screening as a powerful tool for identifying new components of stress

  20. Optimization of laboratory conditions for biosynthesis of type A trichothecenes

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    Bočarov-Stančić Aleksandra S.

    2007-01-01

    Full Text Available Type A trichothecenes, T-2 toxin and diacetoxyscirpenol - DAS, belong to one of the most toxic groups of fusariotoxins. Although larger quantities of them can be found more often in cooler parts of Europe, regarding their metabolic characteristics and the types of illnesses they provoke, it is obvious that even smaller quantities of these toxins can cause serious health disturbances of humans and animals in climatic conditions of Serbia. Having in mind the importance of these substances, the aim of this study was to carry out the optimization of laboratory conditions under which screening of Fusarium spp. isolates from Serbia, regarding T-2 toxin and DAS production, should be done. Four cultures of Fusarium sporotrichioides originating from different regions throughout the world, were under present investigation: ITM-391 (Italy, KF-38/1 (Poland, M-1-1 (Japan and R-2301 (Germany. According to the previous literature data, all of these isolates were T-2 toxin producers, and some of them were also DAS producers. The influence of medium composition (different C and N atoms sources microelements etc, as well as aeration (in liquid media, on biosynthesis process of these mycotoxins, in vitro conditions was investigated. In the case of most Fusarium sporotrichioides isolates, highest yields of T-2 toxin and DAS were achieved under the conditions of more intense aeration, and with the use of glucose (5 or 20% as a C atom source. Fermentation in semi-synthetic liquid medium, using a rotary shaker, was more suitable for screening the toxicity of the fungal isolates in pure culture because of shorter period of incubation, more simpler sample preparation, obtaining less interfering materials in crude toxin extracts, and possibility for more precise definition of factors influencing the yield of trichothecenes.

  1. Comparing Galactan Biosynthesis in Mycobacterium tuberculosis and Corynebacterium diphtheriae.

    Science.gov (United States)

    Wesener, Darryl A; Levengood, Matthew R; Kiessling, Laura L

    2017-02-17

    The suborder Corynebacterineae encompasses species like Corynebacterium glutamicum, which has been harnessed for industrial production of amino acids, as well as Corynebacterium diphtheriae and Mycobacterium tuberculosis, which cause devastating human diseases. A distinctive component of the Corynebacterineae cell envelope is the mycolyl-arabinogalactan (mAG) complex. The mAG is composed of lipid mycolic acids, and arabinofuranose (Araf) and galactofuranose (Galf) carbohydrate residues. Elucidating microbe-specific differences in mAG composition could advance biotechnological applications and lead to new antimicrobial targets. To this end, we compare and contrast galactan biosynthesis in C. diphtheriae and M. tuberculosis In each species, the galactan is constructed from uridine 5'-diphosphate-α-d-galactofuranose (UDP-Galf), which is generated by the enzyme UDP-galactopyranose mutase (UGM or Glf). UGM and the galactan are essential in M. tuberculosis, but their importance in Corynebacterium species was not known. We show that small molecule inhibitors of UGM impede C. glutamicum growth, suggesting that the galactan is critical in corynebacteria. Previous cell wall analysis data suggest the galactan polymer is longer in mycobacterial species than corynebacterial species. To explore the source of galactan length variation, a C. diphtheriae ortholog of the M. tuberculosis carbohydrate polymerase responsible for the bulk of galactan polymerization, GlfT2, was produced, and its catalytic activity was evaluated. The C. diphtheriae GlfT2 gave rise to shorter polysaccharides than those obtained with the M. tuberculosis GlfT2. These data suggest that GlfT2 alone can influence galactan length. Our results provide tools, both small molecule and genetic, for probing and perturbing the assembly of the Corynebacterineae cell envelope.

  2. Genomics of glycopeptidolipid biosynthesis in Mycobacterium abscessus and M. chelonae

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    Etienne Gilles

    2007-05-01

    Full Text Available Abstract Background The outermost layer of the bacterial surface is of crucial importance because it is in constant interaction with the host. Glycopeptidolipids (GPLs are major surface glycolipids present on various mycobacterial species. In the fast-grower model organism Mycobacterium smegmatis, GPL biosynthesis involves approximately 30 genes all mapping to a single region of 65 kb. Results We have recently sequenced the complete genomes of two fast-growers causing human infections, Mycobacterium abscessus (CIP 104536T and M. chelonae (CIP 104535T. We show here that these two species contain genes corresponding to all those of the M. smegmatis "GPL locus", with extensive conservation of the predicted protein sequences consistent with the production of GPL molecules indistinguishable by biochemical analysis. However, the GPL locus appears to be split into several parts in M. chelonae and M. abscessus. One large cluster (19 genes comprises all genes involved in the synthesis of the tripeptide-aminoalcohol moiety, the glycosylation of the lipopeptide and methylation/acetylation modifications. We provide evidence that a duplicated acetyltransferase (atf1 and atf2 in M. abscessus and M. chelonae has evolved through specialization, being able to transfer one acetyl at once in a sequential manner. There is a second smaller and distant (M. chelonae, 900 kb; M. abscessus, 3 Mb cluster of six genes involved in the synthesis of the fatty acyl moiety and its attachment to the tripeptide-aminoalcohol moiety. The other genes are scattered throughout the genome, including two genes encoding putative regulatory proteins. Conclusion Although these three species produce identical GPL molecules, the organization of GPL genes differ between them, thus constituting species-specific signatures. An hypothesis is that the compact organization of the GPL locus in M. smegmatis represents the ancestral form and that evolution has scattered various pieces throughout the

  3. O-Methyltransferases involved in biphenyl and dibenzofuran biosynthesis.

    Science.gov (United States)

    Khalil, Mohammed N A; Brandt, Wolfgang; Beuerle, Till; Reckwell, Dennis; Groeneveld, Josephine; Hänsch, Robert; Gaid, Mariam M; Liu, Benye; Beerhues, Ludger

    2015-07-01

    Biphenyls and dibenzofurans are the phytoalexins of the Malinae involving apple and pear. Biosynthesis of the defence compounds includes two O-methylation reactions. cDNAs encoding the O-methyltransferase (OMT) enzymes were isolated from rowan (Sorbus aucuparia) cell cultures after treatment with an elicitor preparation from the scab-causing fungus, Venturia inaequalis. The preferred substrate for SaOMT1 was 3,5-dihydroxybiphenyl, supplied by the first pathway-specific enzyme, biphenyl synthase (BIS). 3,5-Dihydroxybiphenyl underwent a single methylation reaction in the presence of S-adenosyl-l-methionine (SAM). The second enzyme, SaOMT2, exhibited its highest affinity for noraucuparin, however the turnover rate was greater with 5-hydroxyferulic acid. Both substrates were only methylated at the meta-positioned hydroxyl group. The substrate specificities of the OMTs and the regiospecificities of their reactions were rationalized by homology modeling and substrate docking. Interaction of the substrates with SAM also took place at a position other than the sulfur group. Expression of SaOMT1, SaOMT2 and SaBIS3 was transiently induced in rowan cell cultures by the addition of the fungal elicitor. While the immediate SaOMT1 products were not detectable in elicitor-treated cell cultures, noraucuparin and noreriobofuran accumulated transiently, followed by increasing levels of the SaOMT2 products aucuparin and eriobofuran. SaOMT1, SaOMT2 and SaBIS3 were N- and C-terminally fused with the super cyan fluorescent protein and a modified yellow fluorescent protein, respectively. All the fluorescent reporter fusions were localized to the cytoplasm of Nicotiana benthamiana leaf epidermis cells. A revised biosynthetic pathway of biphenyls and dibenzofurans in the Malinae is presented.

  4. Effects of UV-B radiation on wax biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, J. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom); Paul, N. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[Inst. of Environmental and Biological Sciences, Lancaster Univ. (United Kingdom); Percy, K. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[Canadian Forest Service, Natural Resources Canada, Fredericton, NB (Canada); Broadbent, P. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[Inst. of Environmental and Biological Sciences, Lancaster Univ. (United Kingdom); McLaughlin, C. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[Canadian Forest Service, Natural Resources Canada, Fredericton, NB (Canada); Mullineaux, P. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[John Innes Inst., Norwich (United Kingdom); Creissen, G. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[John Innes Inst., Norwich (United Kingdom); Wellburn, A. [Dept. of Agricultural and Environmental Science, Newcastle-Upon-Tyne (United Kingdom)]|[Inst. of Environmental and Biological Sciences, Lancaster Univ. (United Kingdom)

    1994-12-31

    Two genotypes of tobacco (Nicotiana tabacum L.) were exposed in controlled environment chambers to three levels of biologically effective ultraviolet-B radiation (UV-B{sub BE}; 280-320nm): 0, 4.54 (ambient) and 5.66 ({approx} 25% enhancement) kJ m{sup -2} d{sup -1}. After 28 days, the quantity of wax deposited on leaf surfaces was determined gravimetrically; epicuticular wax chemical composition was determined by capillary gas chromatography with homologue assignments confirmed by gas chromatography-mass spectrometry. Leaf wettability was assessed by measuring the contact angle of water droplets placed on leaf surfaces. Tobacco wax consisted of three major hydrocarbon classes: Straight-chain alkanes (C{sub 27}-C{sub 33}) which comprised {approx} 59% of the hydrocarbon fraction, containing a predominance of odd-chain alkanes with C{sub 31} as the most abundant homologue; branched-chain alkanes (C{sub 25}-C{sub 32}) which comprised {approx}38% of the hydrocarbon fraction with anteiso 3-methyltriacontane (C{sub 30}) as the predominant homologue; and fatty acids (C{sub 14}-C{sub 18}) which comprised {approx} 3% of the wax. Exposure to enhanced UV-B radiation reduced the quantity of wax on the adaxial surface of the transgenic mutant, and resulted in marked changes in the chemical composition of the wax on the exposed leaf surface. Enhanced UV-B decreased the quantity of straight-chain alkanes, increased the quantity of branched-chain alkanes and fatty acids, and resulted in shifts toward shorter straight-chain lengths. Furthermore, UV-B-induced changes in wax composition were associated with increased wettability of tobacco leaf surfaces. Overall, the data are consistent with the view that UV-B radiation has a direct and fundamental effect on wax biosynthesis. Relationships between the physico-chemical nature of the leaf surface and sensitivity to UV-B radiation are discussed. (orig.)

  5. Aspergillus nidulans galactofuranose biosynthesis affects antifungal drug sensitivity.

    Science.gov (United States)

    Alam, Md Kausar; El-Ganiny, Amira M; Afroz, Sharmin; Sanders, David A R; Liu, Juxin; Kaminskyj, Susan G W

    2012-12-01

    The cell wall is essential for fungal survival in natural environments. Many fungal wall carbohydrates are absent from humans, so they are a promising source of antifungal drug targets. Galactofuranose (Galf) is a sugar that decorates certain carbohydrates and lipids. It comprises about 5% of the Aspergillus fumigatus cell wall, and may play a role in systemic aspergillosis. We are studying Aspergillus wall formation in the tractable model system, A. nidulans. Previously we showed single-gene deletions of three sequential A. nidulans Galf biosynthesis proteins each caused similar hyphal morphogenesis defects and 500-fold reduced colony growth and sporulation. Here, we generated ugeA, ugmA and ugtA strains controlled by the alcA(p) or niiA(p) regulatable promoters. For repression and expression, alcA(p)-regulated strains were grown on complete medium with glucose or threonine, whereas niiA(p)-regulated strains were grown on minimal medium with ammonium or nitrate. Expression was assessed by qPCR and colony phenotype. The alcA(p) and niiA(p) strains produced similar effects: colonies resembling wild type for gene expression, and resembling deletion strains for gene repression. Galf immunolocalization using the L10 monoclonal antibody showed that ugmA deletion and repression phenotypes correlated with loss of hyphal wall Galf. None of the gene manipulations affected itraconazole sensitivity, as expected. Deletion of any of ugmA, ugeA, ugtA, their repression by alcA(p) or niiA(p), OR, ugmA overexpression by alcA(p), increased sensitivity to Caspofungin. Strains with alcA(p)-mediated overexpression of ugeA and ugtA had lower caspofungin sensitivity. Galf appears to play an important role in A. nidulans growth and vigor.

  6. Transcriptional analysis of the Bordetella alcaligin siderophore biosynthesis operon.

    Science.gov (United States)

    Kang, H Y; Armstrong, S K

    1998-02-01

    The alc gene cluster of Bordetella pertussis includes three genes, alcA, alcB, and alcC, which are involved in alcaligin siderophore biosynthesis in response to iron starvation. The production of AlcA, AlcB, and AlcC in Bordetella cells and the transcriptional organization of alcA, alcB, and alcC were investigated by using a set of three alc'-'lacZ gene fusion constructs that were contiguous with the known promoter upstream of alcA and extended to fusion junctions within each alc cistron. All three alc'-'lacZ fusions exhibited iron-repressible reporter gene expression which was abolished by deletion of the 105-bp alcA promoter-operator region. In an immunoblot analysis using a monoclonal antibody specific for beta-galactosidase, the AlcA-LacZ, AlcB-LacZ, and AlcC-LacZ hybrid proteins were detected in Bordetella cells grown under iron-depleted conditions. A B. pertussis mutant in which the 105-bp alcA promoter-operator region was deleted by allelic exchange was unable to produce detectable levels of siderophore. Hybridization analysis using gene-specific probes showed that alc-specific transcript levels in the mutant were negligible compared with those of the wild-type parent. These results confirm that alcA, alcB, and alcC are cotranscribed from an iron-regulated control region immediately upstream of alcA. Transcript analysis using hybridization probes representing regions downstream of alcC demonstrated that alc transcription extends approximately 3.6 kb further downstream from the alcC coding region, suggesting the cotranscription of additional, uncharacterized alcaligin system genes.

  7. Alkane biosynthesis genes in cyanobacteria and their transcriptional organization

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    Stephan eKlähn

    2014-07-01

    Full Text Available In cyanobacteria, alkanes are synthesized from a fatty acyl-ACP by two enzymes, acyl-acyl carrier protein reductase (AAR and aldehyde deformylating oxygenase (ADO. Despite the great interest in the exploitation for biofuel production, nothing is known about the transcriptional organization of their genes or the physiological function of alkane synthesis. The comparison of 115 microarray datasets indicates the relatively constitutive expression of aar and ado genes. The analysis of 181 available genomes showed that in 90% of the genomes both genes are present, likely indicating their physiological relevance. In 61% of them they cluster together with genes encoding acetyl-CoA carboxyl transferase and a short chain dehydrogenase, strengthening the link to fatty acid metabolism and in 76% of the genomes they are located in tandem, suggesting constraints on the gene arrangement. However, contrary to the expectations for an operon, we found in Synechocystis sp. PCC 6803 specific promoters for the two genes, sll0208 (ado and sll0209 (aar, that give rise to monocistronic transcripts. Moreover, the upstream located ado gene is driven by a proximal as well as a second, distal, promoter, from which a third transcript, the ~160 nt sRNA SyR9 is transcribed. Thus, the transcriptional organization of the alkane biosynthesis genes in Synechocystis sp. PCC 6803 is of substantial complexity. We verified all three promoters to function independently from each other and show a similar promoter arrangement also in the more distant Nodularia spumigena, Trichodesmium erythraeum, Anabaena sp. PCC 7120, Prochlorococcus MIT9313 and MED4. The presence of separate regulatory elements and the dominance of monocistronic mRNAs suggest the possible autonomous regulation of ado and aar. The complex transcriptional organization of the alkane synthesis gene cluster has possible metabolic implications and should be considered when manipulating the expression of these genes in

  8. Biosynthesis, characterization, and antimicrobial applications of silver nanoparticles

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    Singh P

    2015-03-01

    of silver nanoparticles by B. frigoritolerans DC2 and its effect on the enhancement of the antmicrobial efficacy of well-known commercial antibiotics. Keywords: Brevibacterium frigoritolerans, biosynthesis, silver nanoparticles, antimicrobial activity, synergistic effect

  9. Circadian regulation of glutathione levels and biosynthesis in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Laura M Beaver

    Full Text Available Circadian clocks generate daily rhythms in neuronal, physiological, and metabolic functions. Previous studies in mammals reported daily fluctuations in levels of the major endogenous antioxidant, glutathione (GSH, but the molecular mechanisms that govern such fluctuations remained unknown. To address this question, we used the model species Drosophila, which has a rich arsenal of genetic tools. Previously, we showed that loss of the circadian clock increased oxidative damage and caused neurodegenerative changes in the brain, while enhanced GSH production in neuronal tissue conferred beneficial effects on fly survivorship under normal and stress conditions. In the current study we report that the GSH concentrations in fly heads fluctuate in a circadian clock-dependent manner. We further demonstrate a rhythm in activity of glutamate cysteine ligase (GCL, the rate-limiting enzyme in glutathione biosynthesis. Significant rhythms were also observed for mRNA levels of genes encoding the catalytic (Gclc and modulatory (Gclm subunits comprising the GCL holoenzyme. Furthermore, we found that the expression of a glutathione S-transferase, GstD1, which utilizes GSH in cellular detoxification, significantly fluctuated during the circadian day. To directly address the role of the clock in regulating GSH-related rhythms, the expression levels of the GCL subunits and GstD1, as well as GCL activity and GSH production were evaluated in flies with a null mutation in the clock genes cycle and period. The rhythms observed in control flies were not evident in the clock mutants, thus linking glutathione production and utilization to the circadian system. Together, these data suggest that the circadian system modulates pathways involved in production and utilization of glutathione.

  10. Potential of Microalgae and Lactobacilli in Biosynthesis of Silver Nanoparticles

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    Dariush Shanehbandi

    2011-09-01

    Full Text Available Introduction: Application of nanoparticles has been extensively increased in last decades. Nanoparticles of noble metals such as gold, platinum and especially silver are widely applied in medical and pharmaceutical applications. Although, variety of physical and chemical methods has been developed for production of metal nanoparticles, because of destructive effects of them on environment, biosynthetic methods have been suggested as a novel alternative. Some bacteria and microalgae have different ranges of potentiality to uptake metal ions and produce nanoparticles during detoxification process. In the present work, we study the potential of three Lactobacilli and three algal species in production of AgNPs in different concentrations of silver nitrate. Methods: Utilizing AAS, XRD and TEM methods, Nannochloropsis oculata, Dunaliella salina and Chlorella vulgaris as three algal species in addition to three Lactobacilli including L. acidophilus, L. casei, L. reuteri were monitored for production of silver nanoparticles. Three concentrations of AgNO3 (0.001, 0.002, 0.005 M and two incubation times (24h and 48h were included in this study. Results: Our findings demonstrated that C. vulgaris, N. oculata and L. acidophilus have the potential of nanosilver production in a culture medium containing 0.001 M of AgNO3 within 24 hours. Also L. casei and L. reuteri species exhibited their potential for production of silver nanoparticles in 0.002 M concentration of AgNO3 in 24 hours. The size range of particles was approximately less than 15 nm. The uptake rate of silver in the five species was between 1.0 to 2.7 mg/g of dry weight. Nanoparticle production was not detected in other treatments and the algae Dunaliella. Conclusion: The biosynthesis of silver nanoparticles in all of three Lactobacilli and two algal species including N. oculata and C. vulgaris was confirmed.

  11. Dehydroepiandrosterone biosynthesis, metabolism, biological effects, and clinical use (analytical review

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    N. P. Goncharov

    2015-04-01

    Full Text Available The review presents the fundamental information on the metabolism of dehydroepiandrosterone (DHEA, its biological role and possibilities of its use for replacement therapy. There were studied species differences in the synthesis of DHEA in the adrenal cortex. It was found that DHEA and DHEA-sulfate are produced only by the adrenal glands of humans and monkeys, including lower monkeys. Their biosynthesis involves the following steps: cholesterol → pregnenolone → 17-hydroxypregnenolone → DHEA. The adrenal glands of other species, including rats and mice do not synthesize DHEA. At the same time, in certain brain structures not only in man and monkey, but also in other animals DHEA and its precursors are synthesized de novo which are denoted as neurosteroids. It was demonstrated that Purkinje cells which play an important role in memory formation and learning are mainly place neurosteroid formation in mammals and other vertebrates. To establish the relationship of age and the level of DHEA and other steroids we studied the dynamics of their levels at different periods of postnatal development of people. Peak concentration DHEA observed in aged 25–30 years. In the interval from 20 to 90 years in humans the level falls approximately for 90 %. Cortisol levels in blood does not vary with age, leading to an imbalance in the ratio of cortisol/DHEA. Proved a major role of DHEA as a source (precursor for the synthesis of biologically active sex steroids – testosterone, estradiol and estrone in peripheral tissues. This review presents the bioavailability of DHEA in various physiological and pathological processes in humans and animals. In animal experiments has shown a higher bioavailability of DHEA in transdermal administration as compared with oral administration as in this case there is no steroid rapid inactivation in the liver during its first passage. According to recent studies there is a pronounced dependence of bioavailability of DHEA

  12. Dehydroepiandrosterone biosynthesis, metabolism, biological effects, and clinical use (analytical review

    Directory of Open Access Journals (Sweden)

    N. P. Goncharov

    2015-01-01

    Full Text Available The review presents the fundamental information on the metabolism of dehydroepiandrosterone (DHEA, its biological role and possibilities of its use for replacement therapy. There were studied species differences in the synthesis of DHEA in the adrenal cortex. It was found that DHEA and DHEA-sulfate are produced only by the adrenal glands of humans and monkeys, including lower monkeys. Their biosynthesis involves the following steps: cholesterol → pregnenolone → 17-hydroxypregnenolone → DHEA. The adrenal glands of other species, including rats and mice do not synthesize DHEA. At the same time, in certain brain structures not only in man and monkey, but also in other animals DHEA and its precursors are synthesized de novo which are denoted as neurosteroids. It was demonstrated that Purkinje cells which play an important role in memory formation and learning are mainly place neurosteroid formation in mammals and other vertebrates. To establish the relationship of age and the level of DHEA and other steroids we studied the dynamics of their levels at different periods of postnatal development of people. Peak concentration DHEA observed in aged 25–30 years. In the interval from 20 to 90 years in humans the level falls approximately for 90 %. Cortisol levels in blood does not vary with age, leading to an imbalance in the ratio of cortisol/DHEA. Proved a major role of DHEA as a source (precursor for the synthesis of biologically active sex steroids – testosterone, estradiol and estrone in peripheral tissues. This review presents the bioavailability of DHEA in various physiological and pathological processes in humans and animals. In animal experiments has shown a higher bioavailability of DHEA in transdermal administration as compared with oral administration as in this case there is no steroid rapid inactivation in the liver during its first passage. According to recent studies there is a pronounced dependence of bioavailability of DHEA

  13. Mosaic origin of the heme biosynthesis pathway in photosynthetic eukaryotes.

    Science.gov (United States)

    Oborník, Miroslav; Green, Beverley R

    2005-12-01

    Heme biosynthesis represents one of the most essential metabolic pathways in living organisms, providing the precursors for cytochrome prosthetic groups, photosynthetic pigments, and vitamin B(12). Using genomic data, we have compared the heme pathway in the diatom Thalassiosira pseudonana and the red alga Cyanidioschyzon merolae to those of green algae and higher plants, as well as to those of heterotrophic eukaryotes (fungi, apicomplexans, and animals). Phylogenetic analyses showed the mosaic character of this pathway in photosynthetic eukaryotes. Although most of the algal and plant enzymes showed the expected plastid (cyanobacterial) origin, at least one of them (porphobilinogen deaminase) appears to have a mitochondrial (alpha-proteobacterial) origin. Another enzyme, glutamyl-tRNA synthase, obviously originated in the eukaryotic nucleus. Because all the plastid-targeted sequences consistently form a well-supported cluster, this suggests that genes were either transferred from the primary endosymbiont (cyanobacteria) to the primary host nucleus shortly after the primary endosymbiotic event or replaced with genes from other sources at an equally early time, i.e., before the formation of three primary plastid lineages. The one striking exception to this pattern is ferrochelatase, the enzyme catalyzing the first committed step to heme and bilin pigments. In this case, two red algal sequences do not cluster either with the other plastid sequences or with cyanobacterial sequences and appear to have a proteobacterial origin like that of the apicomplexan parasites Plasmodium and Toxoplasma. Although the heterokonts also acquired their plastid via secondary endosymbiosis from a red alga, the diatom has a typical plastid-cyanobacterial ferrochelatase. We have not found any remnants of the plastidlike heme pathway in the nonphotosynthetic heterokonts Phytophthora ramorum and Phytophthora sojae.

  14. NAD+ biosynthesis ameliorates a zebrafish model of muscular dystrophy.

    Directory of Open Access Journals (Sweden)

    Michelle F Goody

    Full Text Available Muscular dystrophies are common, currently incurable diseases. A subset of dystrophies result from genetic disruptions in complexes that attach muscle fibers to their surrounding extracellular matrix microenvironment. Cell-matrix adhesions are exquisite sensors of physiological conditions and mediate responses that allow cells to adapt to changing conditions. Thus, one approach towards finding targets for future therapeutic applications is to identify cell adhesion pathways that mediate these dynamic, adaptive responses in vivo. We find that nicotinamide riboside kinase 2b-mediated NAD+ biosynthesis, which functions as a small molecule agonist of muscle fiber-extracellular matrix adhesion, corrects dystrophic phenotypes in zebrafish lacking either a primary component of the dystrophin-glycoprotein complex or integrin alpha7. Exogenous NAD+ or a vitamin precursor to NAD+ reduces muscle fiber degeneration and results in significantly faster escape responses in dystrophic embryos. Overexpression of paxillin, a cell adhesion protein downstream of NAD+ in this novel cell adhesion pathway, reduces muscle degeneration in zebrafish with intact integrin receptors but does not improve motility. Activation of this pathway significantly increases organization of laminin, a major component of the extracellular matrix basement membrane. Our results indicate that the primary protective effects of NAD+ result from changes to the basement membrane, as a wild-type basement membrane is sufficient to increase resilience of dystrophic muscle fibers to damage. The surprising result that NAD+ supplementation ameliorates dystrophy in dystrophin-glycoprotein complex- or integrin alpha7-deficient zebrafish suggests the existence of an additional laminin receptor complex that anchors muscle fibers to the basement membrane. We find that integrin alpha6 participates in this pathway, but either integrin alpha7 or the dystrophin-glycoprotein complex is required in conjunction

  15. Biosynthesis of 2-hydroxyisobutyric acid (2-HIBA from renewable carbon

    Directory of Open Access Journals (Sweden)

    Müller Roland H

    2010-02-01

    Full Text Available Abstract Nowadays a growing demand for green chemicals and cleantech solutions is motivating the industry to strive for biobased building blocks. We have identified the tertiary carbon atom-containing 2-hydroxyisobutyric acid (2-HIBA as an interesting building block for polymer synthesis. Starting from this carboxylic acid, practically all compounds possessing the isobutane structure are accessible by simple chemical conversions, e. g. the commodity methacrylic acid as well as isobutylene glycol and oxide. During recent years, biotechnological routes to 2-HIBA acid have been proposed and significant progress in elucidating the underlying biochemistry has been made. Besides biohydrolysis and biooxidation, now a bioisomerization reaction can be employed, converting the common metabolite 3-hydroxybutyric acid to 2-HIBA by a novel cobalamin-dependent CoA-carbonyl mutase. The latter reaction has recently been discovered in the course of elucidating the degradation pathway of the groundwater pollutant methyl tert-butyl ether (MTBE in the new bacterial species Aquincola tertiaricarbonis. This discovery opens the ground for developing a completely biotechnological process for producing 2-HIBA. The mutase enzyme has to be active in a suitable biological system producing 3-hydroxybutyryl-CoA, which is the precursor of the well-known bacterial bioplastic polyhydroxybutyrate (PHB. This connection to the PHB metabolism is a great advantage as its underlying biochemistry and physiology is well understood and can easily be adopted towards producing 2-HIBA. This review highlights the potential of these discoveries for a large-scale 2-HIBA biosynthesis from renewable carbon, replacing conventional chemistry as synthesis route and petrochemicals as carbon source.

  16. Biosynthesis of the Snowdrop (Galanthus nivalis) Lectin in Ripening Ovaries.

    Science.gov (United States)

    Van Damme, E J; Peumans, W J

    1988-03-01

    The biosynthesis and processing of the Galanthus nivalis agglutinin were studied in vivo in ripening snowdrop ovaries. Using labeling and pulse chase labeling experiments it could be demonstrated that the snowdrop lectin is synthesized as a precursor of relative molecular weight (M(r)) 15,000 which is posttranslationally converted into the authentic lectin polypeptide of M(r) 13,000 with a half-life of about 6 hours. Gel filtration of an extract of [(3)H]leucine labeled ovaries on Sepharose 4B showed that a significant portion of the newly synthesized lectin is associated with the particulate fraction. When the organellar fraction was fractionated on isopycnic sucrose gradients this lectin banded in the same density region as the endoplasmic reticulum (ER) marker enzyme NADH cytochrome c reductase. Both radioactivity in lectin and in enzyme activity shifted towards a higher density in the presence of 2 millimolar Mg-acetate indicating that the labeled lectin was associated with the rough ER. Labeled lectin could be chased from the ER with a half-life of 4 hours and then accumulated in the soluble fraction. Whereas the ER-associated lectin contains exclusively polypeptides of M(r) 15,000 the soluble fraction contains both precursor molecules and mature lectin polypeptides. The snowdrop lectin in the ER is fully capable of binding immobilized mannose. It is associated into tetramers with an appropriate molecular weight of 60,000. These results indicate that newly synthesized snowdrop lectin is transiently associated with the ER before transport and processing.

  17. Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

    Directory of Open Access Journals (Sweden)

    Shameli K

    2012-10-01

    Full Text Available Kamyar Shameli,1,2 Mansor Bin Ahmad,1 Ali Zamanian,2 Parvanh Sangpour,2 Parvaneh Shabanzadeh,3 Yadollah Abdollahi,4 Mohsen Zargar51Department of Chemistry, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Materials and Energy Research Center, Karaj, Iran; 3Department of Mathematics, 4Advanced Materials and Nanotechnology Laboratory, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 5Department of Biology, Islamic Azad University, Qom, IranAbstract: Green synthesis of noble metal nanoparticles is a vastly developing area of research. Metallic nanoparticles have received great attention from chemists, physicists, biologists, and engineers who wish to use them for the development of a new-generation of nanodevices. In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant and stabilizer simultaneously. Characterizations of nanoparticles were done using different methods, which included ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier-transform infrared spectroscopy. The ultraviolet-visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 415 nm. Transmission electron microscopy showed that mean diameter and standard deviation for the formation of silver nanoparticles was 6.30 ± 2.64 nm. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The most needed outcome of this work will be the development of value-added products from C. longa for biomedical and nanotechnology-based industries.Keywords: silver nanoparticles, Curcuma longa, biosynthesis, green synthesis, transmission electron microscopy

  18. Two tomato GDP-D-mannose epimerase isoforms involved in ascorbate biosynthesis play specific roles in cell wall biosynthesis and development.

    Science.gov (United States)

    Mounet-Gilbert, Louise; Dumont, Marie; Ferrand, Carine; Bournonville, Céline; Monier, Antoine; Jorly, Joana; Lemaire-Chamley, Martine; Mori, Kentaro; Atienza, Isabelle; Hernould, Michel; Stevens, Rebecca; Lehner, Arnaud; Mollet, Jean Claude; Rothan, Christophe; Lerouge, Patrice; Baldet, Pierre

    2016-08-01

    GDP-D-mannose epimerase (GME, EC 5.1.3.18) converts GDP-D-mannose to GDP-L-galactose, and is considered to be a central enzyme connecting the major ascorbate biosynthesis pathway to primary cell wall metabolism in higher plants. Our previous work demonstrated that GME is crucial for both ascorbate and cell wall biosynthesis in tomato. The aim of the present study was to investigate the respective role in ascorbate and cell wall biosynthesis of the two SlGME genes present in tomato by targeting each of them through an RNAi-silencing approach. Taken individually SlGME1 and SlGME2 allowed normal ascorbate accumulation in the leaf and fruits, thus suggesting the same function regarding ascorbate. However, SlGME1 and SlGME2 were shown to play distinct roles in cell wall biosynthesis, depending on the tissue considered. The RNAi-SlGME1 plants harbored small and poorly seeded fruits resulting from alterations of pollen development and of pollination process. In contrast, the RNAi-SlGME2 plants exhibited vegetative growth delay while fruits remained unaffected. Analysis of SlGME1- and SlGME2-silenced seeds and seedlings further showed that the dimerization state of pectin rhamnogalacturonan-II (RG-II) was altered only in the RNAi-SlGME2 lines. Taken together with the preferential expression of each SlGME gene in different tomato tissues, these results suggest sub-functionalization of SlGME1 and SlGME2 and their specialization for cell wall biosynthesis in specific tomato tissues.

  19. Identification of a hotdog fold thioesterase involved in the biosynthesis of menaquinone in Escherichia coli.

    Science.gov (United States)

    Chen, Minjiao; Ma, Xinyu; Chen, Xiaolei; Jiang, Ming; Song, Haigang; Guo, Zhihong

    2013-06-01

    Escherichia coli is used as a model organism for elucidation of menaquinone biosynthesis, for which a hydrolytic step from 1,4-dihydroxy-2-naphthoyl-coenzyme A (DHNA-CoA) to 1,4-dihydroxy-2-naphthoate is still unaccounted for. Recently, a hotdog fold thioesterase has been shown to catalyze this conversion in phylloquinone biosynthesis, suggesting that its closest homolog, YbgC in Escherichia coli, may be the DHNA-CoA thioesterase in menaquinone biosynthesis. However, this possibility is excluded by the involvement of YbgC in the Tol-Pal system and its complete lack of hydrolytic activity toward DHNA-CoA. To identify the hydrolytic enzyme, we have performed an activity-based screen of all nine Escherichia coli hotdog fold thioesterases and found that YdiI possesses a high level of hydrolytic activity toward DHNA-CoA, with high substrate specificity, and that another thioesterase, EntH, from siderophore biosynthesis exhibits a moderate, much lower DHNA-CoA thioesterase activity. Deletion of the ydiI gene from the bacterial genome results in a significant decrease in menaquinone production, which is little affected in ΔybgC and ΔentH mutants. These results support the notion that YdiI is the DHNA-CoA thioesterase involved in the biosynthesis of menaquinone in the model bacterium.

  20. Cholesterol in mouse retina originates primarily from in situ de novo biosynthesis.

    Science.gov (United States)

    Lin, Joseph B; Mast, Natalia; Bederman, Ilya R; Li, Yong; Brunengraber, Henri; Björkhem, Ingemar; Pikuleva, Irina A

    2016-02-01

    The retina, a thin tissue in the back of the eye, has two apparent sources of cholesterol: in situ biosynthesis and cholesterol available from the systemic circulation. The quantitative contributions of these two cholesterol sources to the retinal cholesterol pool are unknown and have been determined in the present work. A new methodology was used. Mice were given separately deuterium-labeled drinking water and chow containing 0.3% deuterium-labeled cholesterol. In the retina, the rate of total cholesterol input was 21 μg of cholesterol/g retina • day, of which 15 μg of cholesterol/g retina • day was provided by local biosynthesis and 6 μg of cholesterol/g retina • day was uptaken from the systemic circulation. Thus, local cholesterol biosynthesis accounts for the majority (72%) of retinal cholesterol input. We also quantified cholesterol input to mouse brain, the organ sharing important similarities with the retina. The rate of total cerebral cholesterol input was 121 μg of cholesterol/g brain • day with local biosynthesis providing 97% of total cholesterol input. Our work addresses a long-standing question in eye research and adds new knowledge to the potential use of statins (drugs that inhibit cholesterol biosynthesis) as therapeutics for age-related macular degeneration, a common blinding disease.

  1. The genes and enzymes involved in the biosynthesis of thiamin and thiamin diphosphate in yeasts.

    Science.gov (United States)

    Kowalska, Ewa; Kozik, Andrzej

    2008-01-01

    Thiamin (vitamin B1) is an essential molecule for all living organisms. Its major biologically active derivative is thiamin diphosphate, which serves as a cofactor for several enzymes involved in carbohydrate and amino acid metabolism. Important new functions for thiamin and its phosphate esters have recently been suggested, e.g. in gene expression regulation by influencing mRNA structure, in DNA repair after UV illumination, and in the protection of some organelles against reactive oxygen species. Unlike higher animals, which rely on nutritional thiamin intake, yeasts can synthesize thiamin de novo. The biosynthesis pathways include the separate synthesis of two precursors, 4-amino-5-hydroxymethyl-2-methylpyrimidine diphosphate and 5-(2-hydroxyethyl)-4-methylthiazole phosphate, which are then condensed into thiamin monophosphate. Additionally, yeasts evolved salvage mechanisms to utilize thiamin and its dephosphorylated late precursors, 4-amino-5-hydroxymethyl-2-methylpyrimidine and 5-(2-hydroxyethyl)-4-methylthiazole, from the environment. The current state of knowledge on the discrete steps of thiamin biosynthesis in yeasts is far from satisfactory; many intermediates are postulated only by analogy to the much better understood biosynthesis process in bacteria. On the other hand, the genetic mechanisms regulating thiamin biosynthesis in yeasts are currently under extensive exploration. Only recently, the structures of some of the yeast enzymes involved in thiamin biosynthesis, such as thiamin diphosphokinase and thiazole synthase, were determined at the atomic resolution, and mechanistic proposals for the catalysis of particular biosynthetic steps started to emerge.

  2. Molecular mechanisms of the coordination between astaxanthin and fatty acid biosynthesis in Haematococcus pluvialis (Chlorophyceae).

    Science.gov (United States)

    Chen, Guanqun; Wang, Baobei; Han, Danxiang; Sommerfeld, Milton; Lu, Yinghua; Chen, Feng; Hu, Qiang

    2015-01-01

    Astaxanthin, a red ketocarotenoid with strong antioxidant activity and high commercial value, possesses important physiological functions in astaxanthin-producing microalgae. The green microalga Haematococcus pluvialis accumulates up to 4% fatty acid-esterified astaxanthin (by dry weight), and is used as a model species for exploring astaxanthin biosynthesis in unicellular photosynthetic organisms. Although coordination of astaxanthin and fatty acid biosynthesis in a stoichiometric fashion was observed in H. pluvialis, the interaction mechanism is unclear. Here we dissected the molecular mechanism underlying coordination between the two pathways in H. pluvialis. Our results eliminated possible coordination of this inter-dependence at the transcriptional level, and showed that this interaction was feedback-coordinated at the metabolite level. In vivo and in vitro experiments indicated that astaxanthin esterification drove the formation and accumulation of astaxanthin. We further showed that both free astaxanthin biosynthesis and esterification occurred in the endoplasmic reticulum, and that certain diacylglycerol acyltransferases may be the candidate enzymes catalyzing astaxanthin esterification. A model of astaxanthin biosynthesis in H. pluvialis was subsequently proposed. These findings provide further insights into astaxanthin biosynthesis in H. pluvialis.

  3. Transcriptome Analysis Reveals Putative Genes Involved in Iridoid Biosynthesis in Rehmannia glutinosa

    Directory of Open Access Journals (Sweden)

    Xianen Li

    2012-10-01

    Full Text Available Rehmannia glutinosa, one of the most widely used herbal medicines in the Orient, is rich in biologically active iridoids. Despite their medicinal importance, no molecular information about the iridoid biosynthesis in this plant is presently available. To explore the transcriptome of R. glutinosa and investigate genes involved in iridoid biosynthesis, we used massively parallel pyrosequencing on the 454 GS FLX Titanium platform to generate a substantial EST dataset. Based on sequence similarity searches against the public sequence databases, the sequences were first annotated and then subjected to Gene Ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG based analysis. Bioinformatic analysis indicated that the 454 assembly contained a set of genes putatively involved in iridoid biosynthesis. Significantly, homologues of the secoiridoid pathway genes that were only identified in terpenoid indole alkaloid producing plants were also identified, whose presence implied that route II iridoids and route I iridoids share common enzyme steps in the early stage of biosynthesis. The gene expression patterns of four prenyltransferase transcripts were analyzed using qRT-PCR, which shed light on their putative functions in tissues of R. glutinosa. The data explored in this study will provide valuable information for further studies concerning iridoid biosynthesis.

  4. epsilon-N-trimethyllysine availability regulates the rate of carnitine biosynthesis in the growing rat

    Energy Technology Data Exchange (ETDEWEB)

    Rebouche, C.J.; Lehman, L.J.; Olson, L.

    1986-05-01

    Rates of carnitine biosynthesis in mammals depend on the availability of substrates and the activity of enzymes subserving the pathway. This study was undertaken to test the hypothesis that the availability of epsilon-N-trimethyllysine is rate-limiting for synthesis of carnitine in the growing rat and to evaluate diet as a source of this precursor for carnitine biosynthesis. Rats apparently absorbed greater than 90% of a tracer dose of (methyl-/sup 3/H)epsilon-N-trimethyllysine, and approximately 30% of that was incorporated into tissues as (/sup 3/H)carnitine. Rats given oral supplements of epsilon-N-trimethyllysine (0.5-20 mg/d), but no dietary carnitine, excreted more carnitine than control animals receiving no dietary epsilon-N-trimethyllysine or carnitine. Rates of carnitine excretion increased in a dose-dependent manner. Tissue and serum levels of carnitine also increased with dietary epsilon-N-trimethyllysine supplementation. There was no evidence that the capacity for carnitine biosynthesis was saturated even at the highest level of oral epsilon-N-trimethyllysine supplementation. Common dietary proteins (casein, soy protein and wheat gluten) were found to be poor sources of epsilon-N-trimethyllysine for carnitine biosynthesis. The results of this study indicate that the availability of epsilon-N-trimethyllysine limits the rate of carnitine biosynthesis in the growing rat.

  5. BIOSYNTHESIS OF BACTERIAL CELLULOSE BY МEDUSOMYCES GISEVII

    Directory of Open Access Journals (Sweden)

    E. K. Gladysheva

    2015-01-01

    Full Text Available Summary: Bacterial cellulose is an organic material that is synthesized by microorganisms extracellularly. Bacterial cellulose can be used in various industries. Especially, bacterial cellulose has found its application basically in medicine. The production of bacterial cellulose is a complicated and long process. The principal criterion for the process to be successful is bacterial cellulose to be obtained in a higher yield. Russia is lacking an operating facility to produce bacterial cellulose; therefore, research in this art is the hottest topic. This paper reports details on the biosynthesis of bacterial cellulose by the Мedusomyces gisevii microbe and investigates the effect of active acidity level on the bacterial cellulose synthesis. It was found that the synthesis of bacterial cellulose by the symbiosis of Мedusomyces gisevii does not require pH to be artificially maintained. The substrate concentration effect on the bacterial cellulose yield was also examined. The bacterial cellulose synthesis was witnessed to be conjugated with the acetic-acid bacterium growth, and conditions corresponding to a maximal bacterial cells number correspond to a maximum microbial cellulose yield. The maximal bacterial cell number was observed when the glucose concentration in the broth was 20 g/l; as the glucose concentration was increased to 55 g/L, the acetic-acid bacterial cell number diminished in inverse proportion to the substrate concentration, which is likely due to the substrate inhibition. A glucose concentration of 15 g/l and lower is not enough, causing a decrease in the cell number, which is directly proportional to a decline in the substrate concentration. The maximum bacterial cellulose yield (8.7-9.0 % was achieved at an initial glucose concentration of 20-25 g/l in the broth. The conditions providing the maximum bacterial cellulose yield gave an enlarged bacterial cellulose specimen 605 g in weight. The physicochemical properties of the

  6. Inhibition of somatotroph growth and growth hormone biosynthesis by activin in vitro

    DEFF Research Database (Denmark)

    Billestrup, Nils; González-Manchón, C; Potter, E

    1990-01-01

    ]methionine-labeled cells, could be observed after 24 h of activin treatment, and maximal (70%) inhibition of GH biosynthesis was observed after 3 days. Activin inhibited basal as well as GH-releasing factor (GRF)-, glucocorticoid-, and thyroid hormone-stimulated GH biosynthesis. Inhibin, which is known to reverse...... the effect of activin on FSH secretion, did not reverse the effect of activin on GH biosynthesis. Treatment of somatotrophs with activin for 3 days completely inhibited the growth-promoting effect of GRF on somatotrophs. However, no effect of activin on GRF-stimulated expression of the c-fos protooncogene...... was observed. These data demonstrate that activin, in addition to its stimulatory effect on FSH secretion, is able to inhibit both expression of GH and growth of somatotropic cells....

  7. Bacterial diterpene synthases: new opportunities for mechanistic enzymology and engineered biosynthesis.

    Science.gov (United States)

    Smanski, Michael J; Peterson, Ryan M; Huang, Sheng-Xiong; Shen, Ben

    2012-04-01

    Diterpenoid biosynthesis has been extensively studied in plants and fungi, yet cloning and engineering diterpenoid pathways in these organisms remain challenging. Bacteria are emerging as prolific producers of diterpenoid natural products, and bacterial diterpene synthases are poised to make significant contributions to our understanding of terpenoid biosynthesis. Here we will first survey diterpenoid natural products of bacterial origin and briefly review their biosynthesis with emphasis on diterpene synthases (DTSs) that channel geranylgeranyl diphosphate to various diterpenoid scaffolds. We will then highlight differences of DTSs of bacterial and higher organism origins and discuss the challenges in discovering novel bacterial DTSs. We will conclude by discussing new opportunities for DTS mechanistic enzymology and applications of bacterial DTS in biocatalysis and metabolic pathway engineering.

  8. The topology and regulation of cardiolipin biosynthesis and remodeling in yeast.

    Science.gov (United States)

    Baile, Matthew G; Lu, Ya-Wen; Claypool, Steven M

    2014-04-01

    The signature mitochondrial phospholipid cardiolipin plays an important role in mitochondrial function, and alterations in cardiolipin metabolism are associated with human disease. Topologically, cardiolipin biosynthesis and remodeling are complex. Precursor phospholipids must be transported from the ER, across the mitochondrial outer membrane to the matrix-facing leaflet of the inner membrane, where cardiolipin biosynthesis commences. Post-synthesis, cardiolipin undergoes acyl chain remodeling, requiring additional trafficking steps, before it achieves its final distribution within both mitochondrial membranes. This process is regulated at several points via multiple independent mechanisms. Here, we review the regulation and topology of cardiolipin biosynthesis and remodeling in the yeast Saccharomyces cerevisiae. Although cardiolipin metabolism is more complicated in mammals, yeast have been an invaluable model for dissecting the steps required for this process.

  9. Vitamin and co-factor biosynthesis pathways in Plasmodium and other apicomplexan parasites

    Science.gov (United States)

    Müller, Sylke; Kappes, Barbara

    2007-01-01

    Vitamins are essential components of the human diet. By contrast, the malaria parasite Plasmodium falciparum and related apicomplexan parasites synthesise certain vitamins, de novo, either completely or in parts. The occurrence of the various biosynthesis pathways is specific to different apicomplexan parasites, emphasising their distinct requirements for nutrients and growth factors. The absence of vitamin biosynthesis from the human host implies that inhibition of the parasite pathways may be a way to interfere specifically with parasite development. However, the precise role of biosynthesis and potential uptake of vitamins for the overall regulation of vitamin homeostasis in the parasites needs to be established first. In this review Sylke Müller and Barbara Kappes focus mainly on the procurement of vitamin B1, B5 and B6 by Plasmodium and other apicomplexan parasites. PMID:17276140

  10. Vitamin and cofactor biosynthesis pathways in Plasmodium and other apicomplexan parasites.

    Science.gov (United States)

    Müller, Sylke; Kappes, Barbara

    2007-03-01

    Vitamins are essential components of the human diet. By contrast, the malaria parasite Plasmodium falciparum and related apicomplexan parasites synthesize certain vitamins de novo, either completely or in parts. The various biosynthesis pathways are specific to different apicomplexan parasites and emphasize the distinct requirements of these parasites for nutrients and growth factors. The absence of vitamin biosynthesis in humans implies that inhibition of the parasite pathways might be a way to interfere specifically with parasite development. However, the roles of biosynthesis and uptake of vitamins in the regulation of vitamin homeostasis in parasites needs to be established first. In this article, the procurement of vitamins B(1), B(5) and B(6) by Plasmodium and other apicomplexan parasites is discussed.

  11. Plastidic aspartate aminotransferases and the biosynthesis of essential amino acids in plants.

    Science.gov (United States)

    de la Torre, Fernando; Cañas, Rafael A; Pascual, M Belén; Avila, Concepción; Cánovas, Francisco M

    2014-10-01

    In the chloroplasts and in non-green plastids of plants, aspartate is the precursor for the biosynthesis of different amino acids and derived metabolites that play distinct and important roles in plant growth, reproduction, development or defence. Aspartate biosynthesis is mediated by the enzyme aspartate aminotransferase (EC 2.6.1.1), which catalyses the reversible transamination between glutamate and oxaloacetate to generate aspartate and 2-oxoglutarate. Plastids contain two aspartate aminotransferases: a eukaryotic-type and a prokaryotic-type bifunctional enzyme displaying aspartate and prephenate aminotransferase activities. A general overview of the biochemistry, regulation, functional significance, and phylogenetic origin of both enzymes is presented. The roles of these plastidic aminotransferases in the biosynthesis of essential amino acids are discussed.

  12. A chloroplast pathway for the de novo biosynthesis of triacylglycerol in Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Fan, J.; Xu, C.; Andre, C.

    2011-06-23

    Neutral lipid metabolism has been extensively studied in yeast, plants and mammals. In contrast, little information is available regarding the biochemical pathway, enzymes and regulatory factors involved in the biosynthesis of triacylglycerol (TAG) in microalgae. In the conventional TAG biosynthetic pathway widely accepted for yeast, plants and mammals, TAG is assembled in the endoplasmic reticulum (ER) from its immediate precursor diacylglycerol (DAG) made by ER-specific acyltransferases, and is deposited exclusively in lipid droplets in the cytosol. Here, we demonstrated that the unicellular microalga Chlamydomonas reinhardtii employs a distinct pathway that uses DAG derived almost exclusively from the chloroplast to produce TAG. This unique TAG biosynthesis pathway is largely dependent on de novo fatty acid synthesis, and the TAG formed in this pathway is stored in lipid droplets in both the chloroplast and the cytosol. These findings have wide implications for understanding TAG biosynthesis and storage and other areas of lipid metabolism in microalgae and other organisms.

  13. Differential expression of ethylene biosynthesis genes in drupelets and receptacle of raspberry (Rubus idaeus).

    Science.gov (United States)

    Fuentes, Lida; Monsalve, Liliam; Morales-Quintana, Luis; Valdenegro, Mónika; Martínez, Juan-Pablo; Defilippi, Bruno G; González-Agüero, Mauricio

    2015-05-01

    Red Raspberry (Rubus idaeus) is traditionally classified as non-climacteric, and the role of ethylene in fruit ripening is not clear. The available information indicates that the receptacle, a modified stem that supports the drupelets, is involved in ethylene production of ripe fruits. In this study, we report receptacle-related ethylene biosynthesis during the ripening of fruits of cv. Heritage. In addition, the expression pattern of ethylene biosynthesis transcripts was evaluated during the ripening process. The major transcript levels of 1-aminocyclopropane-1-carboxylic acid synthase (RiACS1) and 1-aminocyclopropane-1-carboxylic acid oxidase (RiACO1) were concomitant with ethylene production, increased total soluble solids (TSS) and decreased titratable acidity (TA) and fruit firmness. Moreover, ethylene biosynthesis and transcript levels of RiACS1 and RiACO1 were higher in the receptacle, sustaining the receptacle's role as a source of ethylene in regulating the ripening of raspberry.

  14. Phosphoglycerate Mutase 1 Coordinates Glycolysis and Biosynthesis to Promote Tumor Growth

    Energy Technology Data Exchange (ETDEWEB)

    Hitosugi, Taro [Emory Univ. School of Medicine, Atlanta, GA (United States); Zhou, Lu [Univ. of Chicago, IL (United States); Elf, Shannon [Emory Univ. School of Medicine, Atlanta, GA (United States); Fan, Jun [Emory Univ. School of Medicine, Atlanta, GA (United States); Kang, Hee-Bum [Emory Univ. School of Medicine, Atlanta, GA (United States); Seo, Jae Ho [Emory Univ. School of Medicine, Atlanta, GA (United States); Shan, Changliang [Emory Univ. School of Medicine, Atlanta, GA (United States); Dai, Qing [Univ. of Chicago, IL (United States); Zhang, Liang [Univ. of Chicago, IL (United States); Xie, Jianxin [Cell Signaling Technology, Inc., Danvers, MA (United States); Gu, Ting-Lei [Cell Signaling Technology, Inc., Danvers, MA (United States); Jin, Peng [Emory Univ. School of Medicine, Atlanta, GA (United States); Alečković, Masa [Princeton Univ., NJ (United States); LeRoy, Gary [Princeton Univ., NJ (United States); Kang, Yibin [Princeton Univ., NJ (United States); Sudderth, Jessica A. [UT Southwestern Medical Center, Dallas, TX (United States); DeBerardinis, Ralph J. [UT Southwestern Medical Center, Dallas, TX (United States); Luan, Chi-Hao [Northwestern Univ., Evanston, IL (United States); Chen, Georgia Z. [Emory Univ. School of Medicine, Atlanta, GA (United States); Muller, Susan [Emory Univ. School of Medicine, Atlanta, GA (United States); Shin, Dong M. [Emory Univ. School of Medicine, Atlanta, GA (United States); Owonikoko, Taofeek K. [Emory Univ. School of Medicine, Atlanta, GA (United States); Lonial, Sagar [Emory Univ. School of Medicine, Atlanta, GA (United States); Arellano, Martha L. [Emory Univ. School of Medicine, Atlanta, GA (United States); Khoury, Hanna J. [Emory Univ. School of Medicine, Atlanta, GA (United States); Khuri, Fadlo R. [Emory Univ. School of Medicine, Atlanta, GA (United States); Lee, Benjamin H. [Novartis Inst. for BioMedical Research, Cambridge, MA (United States); Ye, Keqiang [Emory Univ. School of Medicine, Atlanta, GA (United States); Boggon, Titus J. [Yale Univ. School of Medicine, New Haven, CT (United States); Kang, Sumin [Emory Univ. School of Medicine, Atlanta, GA (United States); He, Chuan [Univ. of Chicago, IL (United States); Chen, Jing [Emory Univ. School of Medicine, Atlanta, GA (United States)

    2012-11-12

    It is unclear how cancer cells coordinate glycolysis and biosynthesis to support rapidly growing tumors. We found that the glycolytic enzyme phosphoglycerate mutase 1 (PGAM1), commonly upregulated in human cancers due to loss of TP53, contributes to biosynthesis regulation partially by controlling intracellular levels of its substrate, 3-phosphoglycerate (3-PG), and product, 2-phosphoglycerate (2-PG). 3-PG binds to and inhibits 6-phosphogluconate dehydrogenase in the oxidative pentose phosphate pathway (PPP), while 2-PG activates 3-phosphoglycerate dehydrogenase to provide feedback control of 3-PG levels. Inhibition of PGAM1 by shRNA or a small molecule inhibitor PGMI-004A results in increased 3-PG and decreased 2-PG levels in cancer cells, leading to significantly decreased glycolysis, PPP flux and biosynthesis, as well as attenuated cell proliferation and tumor growth.

  15. Carbohydrate accumulation may be the proximate trigger of anthocyanin biosynthesis under autumn conditions in Begonia semperflorens.

    Science.gov (United States)

    Zhang, K M; Li, Z; Li, Y; Li, Y H; Kong, D Z; Wu, R H

    2013-11-01

    Many plant leaves appear red in the autumn, and many papers have focused on the environmental factors and role of anthocyanin in this process. However few papers have examined the substances that are induced during this process. We hypothesised that excess sugar accumulation directly induces anthocyanin accumulation under autumn conditions. Using two methods (restricting phloem movement and exogenous sucrose feeding), we found that both surplus photosynthate and exogenous sucrose could induce anthocyanin biosynthesis, corresponding to up-regulation of several enzymes involved in anthocyanin biosynthesis (phenylalanine ammonia lyase, chalcone isomerase, dihydroflavonol 4-reductase and flavonoid 3-O-glucosyl transferase) and in transport (glutathione S-transferase). Our results suggest that excess carbohydrate may be the proximate trigger for induction of anthocyanin biosynthesis in autumn, but only when carbohydrates are accumulated for storage.

  16. Intracellular Biosynthesis and Antibacterial Activity of Silver Nanoparticles Using Edible Mushrooms

    Directory of Open Access Journals (Sweden)

    Sankaran MIRUNALINI

    2012-11-01

    Full Text Available The process of biosynthesis of silver nanoparticles is a simple, cost effective and eco-friendly approach. Biosynthesis of silver nanoparticles using some commonly available edible mushroom extracts and their antimicrobial activity was demonstrated in the current study. The formation of silver nanoparticles was confirmed by UV, FTIR and SEM and antibacterial activity was tested using disc diffusion method. From the results it is confirmed the successful formation of silver nanoparticles using mushroom extracts; they performed their role as a reducing and capping agent and also exhibited a potent antibacterial activity against S. aureus (gram positive bacteria. Thus the biosynthesis of silver nanoparticles using edible mushroom extract will deserve to be a good candidate as an antibacterial agent.

  17. Cloning and bioinformatic analysis of lovastatin biosynthesis regulatory gene lovE

    Institute of Scientific and Technical Information of China (English)

    HUANG Xin; LI Hao-ming

    2009-01-01

    Background Lovastatin is an effective drug for treatment of hyperlipidemia.This study aimed to clone Iovastatin biosynthesis regulatory gene lovE and analyze the structure and function of its encoding protein.Methods According to the Iovastatin synthase gene sequence from genebank,primers were designed to amplify and clone the Iovastatin biosynthesis regulatory gene lovE from Aspergillus terms genomic DNA.Bioinformatic analysis of lovE and its encoding animo acid sequence was performed through intemet resources and software like DNAMAN.Results Target fragment lovE,almost 1500 bp in length,was amplified from Aspergillus terms genomic DNA and the secondary and three-dimensional structures of LovE protein were predicted.Conclusion In the Iovastatin biosynthesis process lovE is a regulatory gene and LovE protein is a GAL4-1ike transcriptional factor.

  18. Bacterial Diterpene Synthases: New Opportunities for Mechanistic Enzymology and Engineered Biosynthesis

    Science.gov (United States)

    Smanski, Michael J.; Peterson, Ryan M.; Huang, Sheng-Xiong; Shen, Ben

    2012-01-01

    Diterpenoid biosynthesis has been extensively studied in plants and fungi, yet cloning and engineering diterpenoid pathways in these organisms remain challenging. Bacteria are emerging as prolific producers of diterpenoid natural products, and bacterial diterpene synthases are poised to make significant contributions to our understanding of terpenoid biosynthesis. Here we will first survey diterpenoid natural products of bacterial origin and briefly review their biosynthesis with emphasis on diterpene synthases (DTSs) that channel geranylgeranyl diphosphate to various diterpenoid scaffolds. We will then highlight differences of DTSs of bacterial and higher organism origins and discuss the challenges in discovering novel bacterial DTSs. We will conclude by discussing new opportunities for DTS mechanistic enzymology and applications of bacterial DTS in biocatalysis and metabolic pathway engineering. PMID:22445175

  19. Cellular oxido-reductive proteins of Chlamydomonas reinhardtii control the biosynthesis of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Barwal Indu

    2011-12-01

    Full Text Available Abstract Background Elucidation of molecular mechanism of silver nanoparticles (SNPs biosynthesis is important to control its size, shape and monodispersity. The evaluation of molecular mechanism of biosynthesis of SNPs is of prime importance for the commercialization and methodology development for controlling the shape and size (uniform distribution of SNPs. The unicellular algae Chlamydomonas reinhardtii was exploited as a model system to elucidate the role of cellular proteins in SNPs biosynthesis. Results The C. reinhardtii cell free extract (in vitro and in vivo cells mediated synthesis of silver nanoparticles reveals SNPs of size range 5 ± 1 to 15 ± 2 nm and 5 ± 1 to 35 ± 5 nm respectively. In vivo biosynthesized SNPs were localized in the peripheral cytoplasm and at one side of flagella root, the site of pathway of ATP transport and its synthesis related enzymes. This provides an evidence for the involvement of oxidoreductive proteins in biosynthesis and stabilization of SNPs. Alteration in size distribution and decrease of synthesis rate of SNPs in protein-depleted fractions confirmed the involvement of cellular proteins in SNPs biosynthesis. Spectroscopic and SDS-PAGE analysis indicate the association of various proteins on C. reinhardtii mediated in vivo and in vitro biosynthesized SNPs. We have identified various cellular proteins associated with biosynthesized (in vivo and in vitro SNPs by using MALDI-MS-MS, like ATP synthase, superoxide dismutase, carbonic anhydrase, ferredoxin-NADP+ reductase, histone etc. However, these proteins were not associated on the incubation of pre-synthesized silver nanoparticles in vitro. Conclusion Present study provides the indication of involvement of molecular machinery and various cellular proteins in the biosynthesis of silver nanoparticles. In this report, the study is mainly focused towards understanding the role of diverse cellular protein in the synthesis and capping of silver

  20. Direct Ionic Regulation of the Activity of Myo-Inositol Biosynthesis Enzymes in Mozambique Tilapia.

    Science.gov (United States)

    Villarreal, Fernando D; Kültz, Dietmar

    2015-01-01

    Myo-inositol (Ins) is a major compatible osmolyte in many cells, including those of Mozambique tilapia (Oreochromis mossambicus). Ins biosynthesis is highly up-regulated in tilapia and other euryhaline fish exposed to hyperosmotic stress. In this study, enzymatic regulation of two enzymes of Ins biosynthesis, Ins phosphate synthase (MIPS) and inositol monophosphatase (IMPase), by direct ionic effects is analyzed. Specific MIPS and IMPase isoforms from Mozambique tilapia (MIPS-160 and IMPase 1) were selected based on experimental, phylogenetic, and structural evidence supporting their role for Ins biosynthesis during hyperosmotic stress. Recombinant tilapia IMPase 1 and MIPS-160 activity was assayed in vitro at ionic conditions that mimic changes in the intracellular milieu during hyperosmotic stress. The in vitro activities of MIPS-160 and IMPase 1 are highest at alkaline pH of 8.8. IMPase 1 catalytic efficiency is strongly increased during hyperosmolality (particularly for the substrate D-Ins-3-phosphate, Ins-3P), mainly as a result of [Na+] elevation. Furthermore, the substrate-specificity of IMPase 1 towards D-Ins-1-phosphate (Ins-1P) is lower than towards Ins-3P. Because MIPS catalysis results in Ins-3P this results represents additional evidence for IMPase 1 being the isoform that mediates Ins biosynthesis in tilapia. Our data collectively demonstrate that the Ins biosynthesis enzymes are activated under ionic conditions that cells are exposed to during hypertonicity, resulting in Ins accumulation, which, in turn, results in restoration of intracellular ion homeostasis. We propose that the unique and direct ionic regulation of the activities of Ins biosynthesis enzymes represents an efficient biochemical feedback loop for regulation of intracellular physiological ion homeostasis during hyperosmotic stress.

  1. Direct Involvement of the Master Nitrogen Metabolism Regulator GlnR in Antibiotic Biosynthesis in Streptomyces.

    Science.gov (United States)

    He, Juan-Mei; Zhu, Hong; Zheng, Guo-Song; Liu, Pan-Pan; Wang, Jin; Zhao, Guo-Ping; Zhu, Guo-Qiang; Jiang, Wei-Hong; Lu, Yin-Hua

    2016-12-16

    GlnR, an OmpR-like orphan two-component system response regulator, is a master regulator of nitrogen metabolism in the genus Streptomyces In this work, evidence that GlnR is also directly involved in the regulation of antibiotic biosynthesis is provided. In the model strain Streptomyces coelicolor M145, an in-frame deletion of glnR resulted in markedly increased actinorhodin (ACT) production but reduced undecylprodigiosin (RED) biosynthesis when exposed to R2YE culture medium. Transcriptional analysis coupled with DNA binding studies revealed that GlnR represses ACT but activates RED production directly via the pathway-specific activator genes actII-ORF4 and redZ, respectively. The precise GlnR-binding sites upstream of these two target genes were defined. In addition, the direct involvement of GlnR in antibiotic biosynthesis was further identified in Streptomyces avermitilis, which produces the important anthelmintic agent avermectin. We found that S. avermitilis GlnR (GlnRsav) could stimulate avermectin but repress oligomycin production directly through the respective pathway-specific activator genes, aveR and olmRI/RII To the best of our knowledge, this report describes the first experimental evidence demonstrating that GlnR regulates antibiotic biosynthesis directly through pathway-specific regulators in Streptomyces Our results suggest that GlnR-mediated regulation of antibiotic biosynthesis is likely to be universal in streptomycetes. These findings also indicate that GlnR is not only a master nitrogen regulator but also an important controller of secondary metabolism, which may help to balance nitrogen metabolism and antibiotic biosynthesis in streptomycetes.

  2. Direct Ionic Regulation of the Activity of Myo-Inositol Biosynthesis Enzymes in Mozambique Tilapia.

    Directory of Open Access Journals (Sweden)

    Fernando D Villarreal

    Full Text Available Myo-inositol (Ins is a major compatible osmolyte in many cells, including those of Mozambique tilapia (Oreochromis mossambicus. Ins biosynthesis is highly up-regulated in tilapia and other euryhaline fish exposed to hyperosmotic stress. In this study, enzymatic regulation of two enzymes of Ins biosynthesis, Ins phosphate synthase (MIPS and inositol monophosphatase (IMPase, by direct ionic effects is analyzed. Specific MIPS and IMPase isoforms from Mozambique tilapia (MIPS-160 and IMPase 1 were selected based on experimental, phylogenetic, and structural evidence supporting their role for Ins biosynthesis during hyperosmotic stress. Recombinant tilapia IMPase 1 and MIPS-160 activity was assayed in vitro at ionic conditions that mimic changes in the intracellular milieu during hyperosmotic stress. The in vitro activities of MIPS-160 and IMPase 1 are highest at alkaline pH of 8.8. IMPase 1 catalytic efficiency is strongly increased during hyperosmolality (particularly for the substrate D-Ins-3-phosphate, Ins-3P, mainly as a result of [Na+] elevation. Furthermore, the substrate-specificity of IMPase 1 towards D-Ins-1-phosphate (Ins-1P is lower than towards Ins-3P. Because MIPS catalysis results in Ins-3P this results represents additional evidence for IMPase 1 being the isoform that mediates Ins biosynthesis in tilapia. Our data collectively demonstrate that the Ins biosynthesis enzymes are activated under ionic conditions that cells are exposed to during hypertonicity, resulting in Ins accumulation, which, in turn, results in restoration of intracellular ion homeostasis. We propose that the unique and direct ionic regulation of the activities of Ins biosynthesis enzymes represents an efficient biochemical feedback loop for regulation of intracellular physiological ion homeostasis during hyperosmotic stress.

  3. Rapid Extracellular Biosynthesis of Silver Nanoparticles by Cunninghamella phaeospora Culture Supernatant

    Science.gov (United States)

    Ghareib, Mohamed; Tahon, Medhat Abu; Saif, Mona Mostafa; El-Sayed Abdallah, Wafaa

    2016-01-01

    The development of green approaches for the biosynthesis of silver nanoparticles (AgNPs) is of prime significance in the field of nanotechnology research. A fast and eco-friendly protocol for the biosynthesis of extracellular AgNPs using culture supernatant (CS) from the fungus Cunninghamella phaeospora was studied in this work. This CS was proved as a potential new source for the extracellular biosynthesis of AgNPs. The AgNPs were formed at 100 oC and pH 9 within four min of contact between CS and 1mM silver nitrate (AgNO3) solution. Nitrate reductase (NR) was confirmed to play a pivotal role in the biosynthesis of AgNPs. The enzyme expressed its highest activity at 80 oC and pH 9. At 100 oC the enzyme retained 70% of its original activity for one hour. The half-life (T1/2) of the enzyme activity was calculated to be 1.55 h confirming its thermostability. The produced AgNPs were characterized by UV-Vis spectroscopy, high resolution-transmission electron microscope (HR-TEM) and x-ray diffraction (XRD). These NPs showed an absorption peak at 415 nm in UV-Vis spectrum corresponding to the plasmon resonance of AgNPs. Transmission electron micrographs revealed the production of monodispersed spherical NPs with average particle size 14 nm. XRD spectrum of the NPs confirmed the formation of metallic crystalline silver. It was also suggested that the aromatic amino acids play a role in the biosynthesis process. The current research provided an insight on the green biosynthesis of AgNPs including some mechanistic aspects using a new mycogenic source.

  4. Pharmacokinetic and in vivo efficacy studies of the mycobactin biosynthesis inhibitor salicyl-AMS in mice.

    Science.gov (United States)

    Lun, Shichun; Guo, Haidan; Adamson, John; Cisar, Justin S; Davis, Tony D; Chavadi, Sivagami Sundaram; Warren, J David; Quadri, Luis E N; Tan, Derek S; Bishai, William R

    2013-10-01

    Mycobactin biosynthesis in Mycobacterium tuberculosis facilitates iron acquisition, which is required for growth and virulence. The mycobactin biosynthesis inhibitor salicyl-AMS [5'-O-(N-salicylsulfamoyl)adenosine] inhibits M. tuberculosis growth in vitro under iron-limited conditions. Here, we conducted a single-dose pharmacokinetic study and a monotherapy study of salicyl-AMS with mice. Intraperitoneal injection yielded much better pharmacokinetic parameter values than oral administration did. Monotherapy of salicyl-AMS at 5.6 or 16.7 mg/kg significantly inhibited M. tuberculosis growth in the mouse lung, providing the first in vivo proof of concept for this novel antibacterial strategy.

  5. Engineering Microbial Cells for the Biosynthesis of Natural Compounds of Pharmaceutical Significance

    Directory of Open Access Journals (Sweden)

    Philippe Jeandet

    2013-01-01

    Full Text Available Microbes constitute important platforms for the biosynthesis of numerous molecules of pharmaceutical interest such as antitumor, anticancer, antiviral, antihypertensive, antiparasitic, antioxidant, immunological agents, and antibiotics as well as hormones, belonging to various chemical families, for instance, terpenoids, alkaloids, polyphenols, polyketides, amines, and proteins. Engineering microbial factories offers rich opportunities for the production of natural products that are too complex for cost-effective chemical synthesis and whose extraction from their originating plants needs the use of many solvents. Recent progresses that have been made since the millennium beginning with metabolic engineering of microorganisms for the biosynthesis of natural products of pharmaceutical significance will be reviewed.

  6. “Cation-Stitching Cascade”: exquisite control of terpene cyclization in cyclooctatin biosynthesis

    Science.gov (United States)

    Sato, Hajime; Teramoto, Kazuya; Masumoto, Yui; Tezuka, Noriyuki; Sakai, Kenta; Ueda, Shota; Totsuka, Yusuke; Shinada, Tetsuro; Nishiyama, Makoto; Wang, Chao; Kuzuyama, Tomohisa; Uchiyama, Masanobu

    2015-12-01

    Terpene cyclization is orchestrated by terpene cyclases, which are involved in the biosynthesis of various cyclic natural products, but understanding the origin and mechanism of the selectivity of terpene cyclization is challenging. In this work, we describe an in-depth mechanistic study on cyclooctatin biosynthesis by means of theoretical calculations combined with experimental methods. We show that the main framework of cyclooctatin is formed through domino-type carbocation transportation along the terpene chain, which we call a “cation-stitching cascade”, including multiple hydrogen-shifts and a ring rearrangement that elegantly determine the stereoselectivity.

  7. Advances in the Plant Isoprenoid Biosynthesis Pathway and Its Metabolic Engineering

    Institute of Scientific and Technical Information of China (English)

    Yan LIU; Hong WANG; He-Chun YE; Guo-Feng LI

    2005-01-01

    Although the cytosolic isoprenoid biosynthetic pathway, mavolonate pathway, in plants has been known for many years, a new plastidial 1-deoxyxylulose-5-phosphate (DXP) pathway was identified in the past few years and its related intermediates, enzymes, and genes have been characterized quite recently.With a deep insight into the biosynthetic pathway of isoprenoids, investigations into the metabolic engineering of isoprenoid biosynthesis have started to prosper. In the present article, recent advances in the discoveries and regulatory roles of new genes and enzymes in the plastidial isoprenoid biosynthesis path way are reviewed and examples of the metabolic engineering of cytosolic and plastidial isoprenoids biosnthesis are discussed.

  8. An overview of the non-mevalonate pathway for terpenoid biosynthesis in plants

    Indian Academy of Sciences (India)

    Vinod Shanker Dubey; Ritu Bhalla; Rajesh Luthra

    2003-09-01

    Terpenoids are known to have many important biological and physiological functions. Some of them are also known for their pharmaceutical significance. In the late nineties after the discovery of a novel non-mevalonate (non-MVA) pathway, the whole concept of terpenoid biosynthesis has changed. In higher plants, the conventional acetate-mevalonate (Ac-MVA) pathway operates mainly in the cytoplasm and mitochondria and synthesizes sterols, sesquiterpenes and ubiquinones predominantly. The plastidic non-MVA pathway however synthesizes hemi-, mono-, sesqui- and di-terpenes, along with carotenoids and phytol chain of chlorophyll. In this paper, recent developments on terpenoids biosynthesis are reviewed with respect to the non-MVA pathway.

  9. Expanding the Landscape of Diterpene Structural Diversity through Stereochemically Controlled Combinatorial Biosynthesis.

    Science.gov (United States)

    Andersen-Ranberg, Johan; Kongstad, Kenneth Thermann; Nielsen, Morten Thrane; Jensen, Niels Bjerg; Pateraki, Irini; Bach, Søren Spanner; Hamberger, Britta; Zerbe, Philipp; Staerk, Dan; Bohlmann, Jörg; Møller, Birger Lindberg; Hamberger, Björn

    2016-02-01

    Plant-derived diterpenoids serve as important pharmaceuticals, food additives, and fragrances, yet their low natural abundance and high structural complexity limits their broader industrial utilization. By mimicking the modularity of diterpene biosynthesis in plants, we constructed 51 functional combinations of class I and II diterpene synthases, 41 of which are "new-to-nature". Stereoselective biosynthesis of over 50 diterpene skeletons was demonstrated, including natural variants and novel enantiomeric or diastereomeric counterparts. Scalable biotechnological production for four industrially relevant targets was accomplished in engineered strains of Saccharomyces cerevisiae.

  10. Biosynthesis of two dihydropyrrole-polyketides from a marine-derived Penicillium citrinum

    Energy Technology Data Exchange (ETDEWEB)

    Romminger, Stelamar; Pimenta, Eli F.; Berlinck, Roberto G.S., E-mail: rgsberlinck@iqsc.usp.br [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica; Nascimento, Eduardo S.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica

    2012-10-15

    Feeding experiments with {sup 13}C-labeled precursors were performed in order to establish the biosynthesis of two N-acylated dihydro pyrroles, (8E)-1-(2,3-dihydro-1H-pyrrol-1-yl)-2-methyldec- 8-ene-1,3-dione (1) and 1-(2,3-dihydro-1H-pyrrol-1-yl)-2-methyldecane-1,3-dione (2), isolated from the cultures of a marine-derived Penicillium citrinum. The biosynthesis of both, 1 and 2, involves the incorporation of acetate, methionine and ornithine. (author)

  11. Biosynthesis of the labdane diterpene marrubiin in Marrubium vulgare via a non-mevalonate pathway.

    Science.gov (United States)

    Knöss, W; Reuter, B; Zapp, J

    1997-09-01

    The biosynthesis of the furanic labdane diterpene marrubiin has been studied in plantlets and shoot cultures of Marrubium vulgare (Lamiaceae). The use of [2-14C]acetate, [2-14C]pyruvate, [2-14C]mevalonic acid and [U-14C]glucose incorporation experiments showed that the labelling of sterols in etiolated shoot cultures of M. vulgare was in accordance with their biosynthesis via the acetate-mevalonate pathway. In contrast, the incorporation rates of these precursors into the diterpene marrubiin could not be explained by biosynthesis of this compound via the acetate-mevalonate pathway. Cultivation of etiolated shoot cultures of M. vulgare on medium containing [1-13C]glucose and subsequent 13C-NMR spectroscopy of marrubiin led to the conclusion that the biosynthesis of marrubiin follows a non-mevalonate pathway. All isoprenic units of 13C-labelled marrubiin were enriched in those carbons that correspond to positions 1 and 5 of a putative precursor isopentenyl diphosphate. This labelling pattern from [1-13C]glucose is consistent with an alternative pathway via trioses, which has already been shown to occur in Eubacteria and Gymnospermae. The labdane skeleton is a precursor of many other skeletal types of diterpenes. Therefore it becomes obvious that in connection with the few known examples of a non-mevalonate pathway to isoprenoids the formation of some isoprenoids in plants via a non-mevalonate pathway might be quite common.

  12. Extrinsic functions of lectin domains in O-N-acetylgalactosamine glycan biosynthesis

    DEFF Research Database (Denmark)

    Lorenz, Virginia; Ditamo, Yanina; Cejas, Romina B;

    2016-01-01

    Glycan biosynthesis occurs mainly in Golgi. Molecular organization and functional regulation of this process are not well understood. We evaluated the extrinsic effect of lectin domains (β-trefoil fold) of polypeptide GalNAc-transferases (ppGalNAc-Ts) on catalytic activity of glycosyltransferases...

  13. Biosynthesis of catechin components is differentially regulated in dark-treated tea (Camellia sinensis L.).

    Science.gov (United States)

    Hong, Gaojie; Wang, Jie; Zhang, Yong; Hochstetter, Danielle; Zhang, Shuping; Pan, Yue; Shi, Yunlong; Xu, Ping; Wang, Yuefei

    2014-05-01

    Tea (Camellia sinensis L.) is a crop with both commercial and medicinal value with remarkably high polyphenol content in the form of catechins. To understand the molecular regulation of catechin biosynthesis in tea, we treated the tea plants with darkness. We used qRT-PCR to validate the expression of genes involved in catechin biosynthesis. It indicated that dark treatment displayed different effects on the genes participating in tea flavonoid (FL) pathway. The early genes of FL biosynthesis pathway, CHSI, F3H and DFR, remained at steady expression levels when treated by darkness. It is noteworthy that the expression level of LAR increased and the level of ANS decreased under dark conditions. The vanillin assay showed that the dark-treated plants contained lower levels of total catechins than those grown under normal conditions. The HPLC analysis further demonstrated the changes in biosynthesis of catechins under these conditions. In accordance with the gene expression pattern, the content of epicatechins (ECs) declined and that of catechins (Cs) was elevated in response to the darkness. Our study uncovered the molecular mechanisms and biochemical changes of shading in tea cultivation.

  14. Rice Brittleness Mutants: A Way to Open the 'Black Box' of Monocot Cell Wall Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Baocai Zhang; Yihua Zhou

    2011-01-01

    Rice is a model organism for studying the mechanism of cell wall biosynthesis and remolding in Gramineae.Mechanical strength is an important agronomy trait of rice(Oryza sativa L.)plants that affects crop lodging and grain yield.As a prominent physical property of cell walls,mechanical strength reflects upon the structure of different wall polymers and how they interact.Studies on the mechanisms that regulate the mechanical strength therefore consequently results in uncovering the genes functioning in cell wall biosynthesis and remodeling.Our group focuses on the study of isolation of brittle culm(bc)mutants and characterization of their corresponding genes.To date,several bc mutants have been reported.The identified genes have covered several pathways of cell wall biosynthesis,revealing many secrets of monocot cell wall biosynthesis.Here,we review the progress achieved in this research field and also highlight the perspectives in expectancy.All of those lend new insights into mechanisms of cell wall formation and are helpful for harnessing the waste rice straws for biofuel production.

  15. Mutagenesis of NosM Leader Peptide Reveals Important Elements in Nosiheptide Biosynthesis.

    Science.gov (United States)

    Jin, Liang; Wu, Xuri; Xue, Yanjiu; Jin, Yue; Wang, Shuzhen; Chen, Yijun

    2017-02-15

    Nosiheptide, a typical member of the ribosomally synthesized and posttranslationally modified peptides (RiPPs), exhibits potent activity against multidrug-resistant Gram-positive bacterial pathogens. The precursor peptide of nosiheptide (NosM) is comprised of a leader peptide with 37 amino acids and a core peptide containing 13 amino acids. To pinpoint elements in the leader peptide that are essential for nosiheptide biosynthesis, a collection of mutants with unique sequence features, including N- and C-terminal motifs, peptide length, and specific sites in the leader peptide, was generated by mutagenesis in vivo The effects of various mutants on nosiheptide biosynthesis were evaluated. In addition to the necessity of a conserved motif LEIS box, native length and the N-terminal 12 amino acid residues were indispensable, and single-site substitutions of these 12 amino acid residues resulted in changes ranging from a greater-than-5-fold decrease to a 2-fold increase of nosiheptide production, depending on the sites and substituted residues. Moreover, although the C-terminal motif is not conservative, significant effects of this portion on nosiheptide production were also evident. Taken together, the present results further highlight the importance of the leader peptide in nosiheptide biosynthesis, and provide new insights into the diversity and specificity of leader peptides in the biosynthesis of various RiPPs.

  16. Autoxidated linolenic acid inhibits aflatoxin biosynthesis in Aspergillus flavus via oxylipin species.

    Science.gov (United States)

    Yan, Shijuan; Liang, Yating; Zhang, Jindan; Chen, Zhuang; Liu, Chun-Ming

    2015-08-01

    Aflatoxins produced by Aspergillus species are among the most toxic and carcinogenic compounds in nature. Although it has been known for a long time that seeds with high oil content are more susceptible to aflatoxin contamination, the role of fatty acids in aflatoxin biosynthesis remains controversial. Here we demonstrate in A. flavus that both the saturated stearic acid (C18:0) and the polyunsaturated linolenic acid (C18:3) promoted aflatoxin production, while C18:3, but not C18:0, inhibited aflatoxin biosynthesis after exposure to air for several hours. Further experiments showed that autoxidated C18:3 promoted mycelial growth, sporulation, and kojic acid production, but inhibited the expression of genes in the AF biosynthetic gene cluster. Mass spectrometry analyses of autoxidated C18:3 fractions that were able to inhibit aflatoxin biosynthesis led to the identification of multiple oxylipin species. These results may help to clarify the role of fatty acids in aflatoxin biosynthesis, and may explain why controversial results have been obtained for fatty acids in the past.

  17. Biosynthesis of silver nanoparticles using Reseda Luteola L. and their antimicrobial activity

    NARCIS (Netherlands)

    Boroumand, M.N.; Montazer, M.; Dutschk, V.

    2013-01-01

    Among different methods to synthesize silver nanoparticles (SNPs), the biological method has been the most extensively investigated. This study presents a facile and rapid method for biosynthesis of silver nanoparticles from Weld (Reseda Luteola L.) as a natural dye. An aqueous extract of the dye wa

  18. Biosynthesis of 8-O-methylated benzoxazinoid defense compounds in maize

    Science.gov (United States)

    Benzoxazinoids are important defense compounds in grasses. Here, we investigated the biosynthesis and biological roles of the 8-O-methylated benzoxazinoids, DIM2BOA-Glc and HDM2BOA-Glc. Using quantitative trait locus mapping and heterologous expression, we identified a 2-oxoglutarate-dependent dioxy...

  19. Yeast HXK2 gene reverts glucose regulation mutation of penicillin biosynthesis in P. chrysogenum

    Directory of Open Access Journals (Sweden)

    Edmundo A. Pérez

    2014-09-01

    Full Text Available The mutant Penicillium chrysogenum strain dogR5, derived from strain AS-P-78, does not respond to glucose regulation of penicillin biosynthesis and β-galactosidase, and is partially deficient in D-glucose phosphorilating activity. We have transformed strain dogR5 with the (hexokinase hxk2 gene from Saccharomyces cerevisiae. Transformants recovered glucose control of penicillin biosynthesis in different degrees, and acquired a hexokinase (fructose phosphorylating activity absent in strains AS- P-78 and dogR5. Interestingly, they also recovered glucose regulation of β-galactosidase. On the other hand, glucokinase activity was affected in different ways in the transformants; one of which showed a lower activity than the parental dogR5, but normal glucose regulation of penicillin biosynthesis. Our results show that Penicillium chrysogenum AS-P-78 and dogR5 strains lack hexokinase, and suggest that an enzyme with glucokinase activity is involved in glucose regulation of penicillin biosynthesis and β-galactosidase, thus signaling glucose in both primary and secondary metabolism; however, catalytic and signaling activities seem to be independent.

  20. Yeast HXK2 gene reverts glucose regulation mutation of penicillin biosynthesis in P. chrysogenum.

    Science.gov (United States)

    Pérez, Edmundo A; Fernández, Francisco J; Fierro, Francisco; Mejía, Armando; Marcos, Ana T; Martín, Juan F; Barrios-González, Javier

    2014-01-01

    The mutant Penicillium chrysogenum strain dogR5, derived from strain AS-P-78, does not respond to glucose regulation of penicillin biosynthesis and β-galactosidase, and is partially deficient in D-glucose phosphorilating activity. We have transformed strain dogR5 with the (hexokinase) hxk2 gene from Saccharomyces cerevisiae. Transformants recovered glucose control of penicillin biosynthesis in different degrees, and acquired a hexokinase (fructose phosphorylating) activity absent in strains AS- P-78 and dogR5. Interestingly, they also recovered glucose regulation of β-galactosidase. On the other hand, glucokinase activity was affected in different ways in the transformants; one of which showed a lower activity than the parental dogR5, but normal glucose regulation of penicillin biosynthesis. Our results show that Penicillium chrysogenum AS-P-78 and dogR5 strains lack hexokinase, and suggest that an enzyme with glucokinase activity is involved in glucose regulation of penicillin biosynthesis and β-galactosidase, thus signaling glucose in both primary and secondary metabolism; however, catalytic and signaling activities seem to be independent.

  1. The physics of cellulose biosynthesis : polymerization and self-organization, from plants to bacteria

    NARCIS (Netherlands)

    Diotallevi, F.

    2007-01-01

    This thesis deals with many different biological problems concerning cellulose biosynthesis. Cellulose is made by all plants, and therefore it is probably the most abundant organic compound on Earth. Aside from being the primary building material for plants, this biopolymer is of great economic impo

  2. Overexpression of an ABA biosynthesis gene using a stress inducible promoter enhances drought resistance in petunia

    Science.gov (United States)

    Plants respond to drought stress by closing their stomata and reducing transpirational water loss. The plant hormone abscisic acid (ABA) regulates growth and stomatal closure particularly when the plant is under environmental stresses. One of the key enzymes in the ABA biosynthesis of higher plants ...

  3. In vivo inhibition of polyamine biosynthesis and growth in tobacco ovary tissues.

    Science.gov (United States)

    Slocum, R D; Galston, A W

    1985-01-01

    Post fertilization growth of tobacco ovary tissues treated with inhibitors of polyamine (PA) biosynthesis was examined in relation to endogenous PA titers and the activities of arginine decarboxylase (ADC, EC 4.1.1.19) and ornithine decarboxylase (ODC, EC 4.1.1.17). DL-alpha-Difluoromethylornithine (DFMO) and DL-alpha-difluoromethylarginine (DFMA), specific, irreversible ("suicide") inhibitors of ODC and ADC in vitro, were used to modulate PA biosynthesis in excised flowers. ODC represented >99% of the total decarboxylase activity in tobacco ovaries. In vivo inhibition of ODC with DFMO resulted in a significant decrease in PA titers, ovary fresh weight and protein content. Simultaneous inhibition of both decarboxylases by DFMO and DFMA produced only a marginally greater depression in growth and PA titers, indicating that ODC activity is rate-limiting for PA biosynthesis in these tissues. Paradoxically, DFMA alone inhibited PA biosynthesis, not as a result of a specific inhibition of ADC, but primarily through the inactivation of ODC. In vivo inhibition of ODC by DFMA appears to result from arginase-mediated hydrolysis of this inhibitor to urea and DFMO, the suicide substrate for ODC. Putrescine conjugates in tobacco appear to function as a storage form of this amine which, upon hydrolysis, may contribute to Put homeostasis during growth.

  4. Extracellular biosynthesis of functionalized silver nanoparticles by strains of Cladosporium cladosporioides fungus

    NARCIS (Netherlands)

    Balaji, D. S.; Basavaraja, S.; Deshpande, R.; Mahesh, D. Bedre; Prabhakar, B. K.; Venkataraman, A.

    2009-01-01

    In the present investigation, we report the extracellular biosynthesis of silver nanoparticles (AgNP) employing the fungus Cladosporium cladosporioides. The extracellular solution of C. cladosporioides was used for the reduction of AgNO(3) solution to AgNP. The present study includes time dependent

  5. Understanding the Biosynthesis SF2575: A Potent Antitumor Compound With Novel Modes of Action

    Science.gov (United States)

    2009-09-01

    NOTES 14. ABSTRACT: SF2575 is a tetracycline polyketide produced by Streptomyces sp. SF2575 and displays exceptionally potent anticancer activity...engineered biosynthesis of SF2575 analogs. 15. SUBJECT TERMS Anticancer , chemotherapy, Natural product, topoisomerase 16. SECURITY CLASSIFICATION OF...17 4 Introduction Natural products produced by bacteria and fungi encompass a broad range of bioactivity and are an important

  6. Sucrose-specific induction of anthocyanin biosynthesis in Arabidopsis requires the MYB75/PAP1 gene.

    NARCIS (Netherlands)

    Teng, S.; Keurentjes, J.J.B.; Bentsink, L.; Koornneef, M.; Smeekens, S.

    2005-01-01

    Sugar-induced anthocyanin accumulation has been observed in many plant species. We observed that sucrose (Suc) is the most effective inducer of anthocyanin biosynthesis in Arabidopsis (Arabidopsis thaliana) seedlings. Other sugars and osmotic controls are either less effective or ineffective. Analys

  7. Regulation of aromatic amino acid biosynthesis in the ribulose monophosphate cycle methylotroph Nocardia sp. 239

    NARCIS (Netherlands)

    Boer, L. de; Vrijbloed, J.W.; Grobben, G.; Dijkhuizen, L.

    1989-01-01

    The regulation of aromatic amino acid biosynthesis in Nocardia sp. 239 was studied. In cell-free extracts 3-deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase activity was inhibited in a cumulative manner by tryptophan, phenylalanine and tyrosine. Chorismate mutase was inhibited by both phenyl

  8. BioSYNTHESIS: access to a knowledge network of health sciences databases.

    Science.gov (United States)

    Broering, N C; Hylton, J S; Guttmann, R; Eskridge, D

    1991-04-01

    Users of the IAIMS Knowledge Network at the Georgetown University Medical Center have access to multiple in-house and external databases from a single point of entry through BioSYNTHESIS. The IAIMS project has developed a rich environment of biomedical information resources that represent a medical decision support system for campus physicians and students. The BioSYNTHESIS system is an information navigator that provides transparent access to a Knowledge Network of over a dozen databases. These multiple health sciences databases consist of bibliographic, informational, diagnostic, and research systems which reside on diverse computers such as DEC VAXs, SUN 490, AT&T 3B2s, Macintoshes, IBM PC/PS2s and the AT&T ISN and SYTEK network systems. Ethernet and TCP/IP protocols are used in the network architecture. BioSYNTHESIS also provides network links to the other campus libraries and to external institutions. As additional knowledge resources and technological advances have become available. BioSYNTHESIS has evolved from a two phase to a three phase program. Major components of the system including recent achievements and future plans are described.

  9. Are Small GTPases Signal Hubs in Sugar-Mediated Induction of Fructan Biosynthesis?

    NARCIS (Netherlands)

    Ritsema, Tita; Brodmann, David; Diks, Sander H.; Bos, Carina L.; Nagaraj, Vinay; Pieterse, Corne M. J.; Boller, Thomas; Wiemken, Andres; Peppelenbosch, Maikel P.

    2009-01-01

    External sugar initiates biosynthesis of the reserve carbohydrate fructan, but the molecular processes mediating this response remain obscure. Previously it was shown that a phosphatase and a general kinase inhibitor hamper fructan accumulation. We use various phosphorylation inhibitors both in barl

  10. DEWAX-mediated transcriptional repression of cuticular wax biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Suh, Mi Chung; Go, Young Sam

    2014-06-06

    The aerial parts of plants are covered with a cuticular wax layer, which is the first barrier between a plant and its environment. Although cuticular wax deposition increases more in the light than in the dark, little is known about the molecular mechanisms underlying the regulation of cuticular wax biosynthesis. Recently DEWAX (Decrease Wax Biosynthesis) encoding an AP2/ERF transcription factor was found to be preferentially expressed in the epidermis and induced by darkness. Wax analysis of the dewax knockout mutant, wild type, and DEWAX overexpression lines (OX) indicates that DEWAX is a negative regulator of cuticular wax biosynthesis. DEWAX represses the expression of wax biosynthetic genes CER1, LACS2, ACLA2, and ECR via direct interaction with their promoters. Cuticular wax biosynthesis is negatively regulated twice a day by the expression of DEWAX; throughout the night and another for stomata closing. Taken together, it is evident that DEWAX-mediated negative regulation of the wax biosynthetic genes plays role in determining the total wax loads produced in Arabidopsis during daily dark and light cycles. In addition, significantly higher levels of DEWAX transcripts in leaves than stems suggest that DEWAX-mediated transcriptional repression might be involved in the organ-specific regulation of total wax amounts on plant surfaces.

  11. Mathematical model of fructan biosynthesis and polymer length distribution in plants

    DEFF Research Database (Denmark)

    Rasmussen, Gitte Susanne; Thornley, John H. M.; Parsons, Anthony J.;

    2013-01-01

    Background and Aims There are many unresolved issues concerning the biochemistry of fructan biosynthesis. The aim of this paper is to address some of these by means of modelling mathematically the biochemical processes.Methods A model has been constructed for the step-by-step synthesis of fructan...

  12. Ergothioneine Biosynthesis and Functionality in the Opportunistic Fungal Pathogen, Aspergillus fumigatus

    Science.gov (United States)

    Sheridan, Kevin J.; Lechner, Beatrix Elisabeth; Keeffe, Grainne O’; Keller, Markus A.; Werner, Ernst R.; Lindner, Herbert; Jones, Gary W.; Haas, Hubertus; Doyle, Sean

    2016-01-01

    Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a trimethylated and sulphurised histidine derivative which exhibits antioxidant properties. Here we report that deletion of Aspergillus fumigatus egtA (AFUA_2G15650), which encodes a trimodular enzyme, abrogated EGT biosynthesis in this opportunistic pathogen. EGT biosynthetic deficiency in A. fumigatus significantly reduced resistance to elevated H2O2 and menadione, respectively, impaired gliotoxin production and resulted in attenuated conidiation. Quantitative proteomic analysis revealed substantial proteomic remodelling in ΔegtA compared to wild-type under both basal and ROS conditions, whereby the abundance of 290 proteins was altered. Specifically, the reciprocal differential abundance of cystathionine γ-synthase and β-lyase, respectively, influenced cystathionine availability to effect EGT biosynthesis. A combined deficiency in EGT biosynthesis and the oxidative stress response regulator Yap1, which led to extreme oxidative stress susceptibility, decreased resistance to heavy metals and production of the extracellular siderophore triacetylfusarinine C and increased accumulation of the intracellular siderophore ferricrocin. EGT dissipated H2O2 in vitro, and elevated intracellular GSH levels accompanied abrogation of EGT biosynthesis. EGT deficiency only decreased resistance to high H2O2 levels which suggests functionality as an auxiliary antioxidant, required for growth at elevated oxidative stress conditions. Combined, these data reveal new interactions between cellular redox homeostasis, secondary metabolism and metal ion homeostasis. PMID:27748436

  13. Characterization of a negative regulator AveI for avermectin biosynthesis in Streptomyces avermitilis NRRL8165.

    Science.gov (United States)

    Chen, Lei; Lu, Yinhua; Chen, Jun; Zhang, Weiwen; Shu, Dan; Qin, Zhongjun; Yang, Sheng; Jiang, Weihong

    2008-08-01

    A transcriptional activator for actinorhodin biosynthesis, AtrA, was previously characterized in Streptomyces coelicolor A3(2), and an orthologue of atrA, named aveI, is identified in the Streptomyces avermitilis NRRL8165 genome (Uguru et al., Mol Microbiol, 58:131-150, 2005). In this study, genetic and functional characterization of aveI gene was reported. Deletion of aveI gene led to increased biosynthesis of avermectin B1a by about 16-fold. The increased synthesis of avermectin B1a was suppressed by complementation with either aveI gene or its orthologue gene atrA from S. coelicolor, suggesting AveI and AtrA shared the similar functionality and were negative regulators for avermectin biosynthesis in S. avermitilis. However, when aveI was introduced into S. coelicolor on a multi-copy plasmid, the production of actinorhodin was significantly increased, indicating that aveI had a positive effect on actinorhodin biosynthesis in S. coelicolor, the same as its orthologue atrA. Electrophoretic mobility shift assays revealed AveI can bind specifically to the promoter region of actII-ORF4 in vitro but not that of aveR. Although its mechanism still needs to be defined, the species-differential regulation by the same regulator may represent an example of the evolutional strategy that enables bacteria to adapt the existing molecular machinery to a variety of functionalities for growth and survival.

  14. Oleanolic acid and ursolic acid inhibit peptidoglycan biosynthesis in Streptococcus mutans UA159

    Directory of Open Access Journals (Sweden)

    Soon-Nang Park

    2015-06-01

    Full Text Available In this study, we revealed that OA and UA significantly inhibited the expression of most genes related to peptidoglycan biosynthesis in S. mutans UA159. To the best of our knowledge, this is the first report to introduce the antimicrobial mechanism of OA and UA against S. mutans.

  15. Peroxisomal polyhydroxyalkanoate biosynthesis is a promising strategy for bioplastic production in high biomass crops.

    Science.gov (United States)

    Tilbrook, Kimberley; Gebbie, Leigh; Schenk, Peer M; Poirier, Yves; Brumbley, Stevens M

    2011-12-01

    Polyhydroxyalkanoates (PHAs) are bacterial carbon storage polymers with diverse plastic-like properties. PHA biosynthesis in transgenic plants is being developed as a way to reduce the cost and increase the sustainability of industrial PHA production. The homopolymer polyhydroxybutyrate (PHB) is the simplest form of these biodegradable polyesters. Plant peroxisomes contain the substrate molecules and necessary reducing power for PHB biosynthesis, but peroxisomal PHB production has not been explored in whole soil-grown transgenic plants to date. We generated transgenic sugarcane (Saccharum sp.) with the three-enzyme Ralstonia eutropha PHA biosynthetic pathway targeted to peroxisomes. We also introduced the pathway into Arabidopsis thaliana, as a model system for studying and manipulating peroxisomal PHB production. PHB, at levels up to 1.6%-1.8% dry weight, accumulated in sugarcane leaves and A. thaliana seedlings, respectively. In sugarcane, PHB accumulated throughout most leaf cell types in both peroxisomes and vacuoles. A small percentage of total polymer was also identified as the copolymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) in both plant species. No obvious deleterious effect was observed on plant growth because of peroxisomal PHA biosynthesis at these levels. This study highlights how using peroxisomal metabolism for PHA biosynthesis could significantly contribute to reaching commercial production levels of PHAs in crop plants.

  16. Oxalic acid biosynthesis is encoded by an operon in Burkholderia glumae

    Science.gov (United States)

    Although the biosynthesis of oxalic acid is known to occur in a number of bacteria, the mechanism(s) regulating its production remains largely unknown. To date, there is no report on the identification of an oxalic acid biosynthetic pathway gene from bacteria. In an attempt to identify such a gene...

  17. Effect of interleukin-1 on the biosynthesis of proinsulin and insulin in isolated rat pancreatic islets

    DEFF Research Database (Denmark)

    Hansen, Birgit Sehested; Linde, S; Spinas, G A;

    1988-01-01

    Insulin dependent diabetes mellitus (IDDM) is often preceded or associated with lymphocytic infiltration in the islets of Langerhans (insulitis). We recently demonstrated that interleukin-1 (IL-1) produced by activated macrophages exerts a bimodal effect on insulin release and biosynthesis in iso...

  18. Transcriptomic analysis reveals key genes related to betalain biosynthesis in pulp coloration of Hylocereus polyrhizus

    Directory of Open Access Journals (Sweden)

    Hua eQingzhu

    2016-01-01

    Full Text Available Betalains have high nutritional value and bioactivities. Red pulp pitaya (Hylocereus polyrhizus is the only fruit containing abundant betalains for consumer. However, no information is available about genes involved in betalain biosynthesis in H. polyrhizus. Herein, two cDNA libraries of pitaya pulps with two different coloration stages (white and red pulp stages of Guanhuahong (H. polyrhizus were constructed. A total of about 12 Gb raw RNA-Seq data was generated and was de novo assembled into 122,677 transcripts with an average length of 1,183 bp and an N50 value of 2008. Approximately 99.99% of all transcripts were annotated based on seven public databases. A total of 8,871 transcripts were significantly regulated. Thirty-three candidate transcripts related to betalain biosynthesis were obtained from the transcriptome data. Transcripts encoding enzymes involved in betalain biosynthesis were analyzed using RT-qPCR at the whole pulp coloration stages of H. Polyrhizus (7-1 and H. Undatus (132-4. Nine key transcripts of betalain biosynthesis were identified. They were assigned to four kinds of genes in betalain biosynthetic pathway, including tyrosinase, 4, 5-DOPA dioxygenase extradiol, cytochrome P450 and glucosyltransferase. Ultimately, a preliminary betalain biosynthetic pathway for pitaya was proposed based on betalain analyses and gene expression profiles.

  19. Transcriptomic Analysis Reveals Key Genes Related to Betalain Biosynthesis in Pulp Coloration of Hylocereus polyrhizus.

    Science.gov (United States)

    Qingzhu, Hua; Chengjie, Chen; Zhe, Chen; Pengkun, Chen; Yuewen, Ma; Jingyu, Wu; Jian, Zheng; Guibing, Hu; Jietang, Zhao; Yonghua, Qin

    2015-01-01

    Betalains have high nutritional value and bioactivities. Red pulp pitaya (Hylocereus polyrhizus) is the only fruit containing abundant betalains for consumer. However, no information is available about genes involved in betalain biosynthesis in H. polyrhizus. Herein, two cDNA libraries of pitaya pulps with two different coloration stages (white and red pulp stages) of Guanhuahong (H. polyrhizus) were constructed. A total of about 12 Gb raw RNA-Seq data was generated and was de novo assembled into 122,677 transcripts with an average length of 1183 bp and an N50 value of 2008. Approximately 99.99% of all transcripts were annotated based on seven public databases. A total of 8871 transcripts were significantly regulated. Thirty-three candidate transcripts related to betalain biosynthesis were obtained from the transcriptome data. Transcripts encoding enzymes involved in betalain biosynthesis were analyzed using RT-qPCR at the whole pulp coloration stages of H. polyrhizus (7-1) and H. undatus (132-4). Nine key transcripts of betalain biosynthesis were identified. They were assigned to four kinds of genes in betalain biosynthetic pathway, including tyrosinase, 4, 5-DOPA dioxygenase extradiol, cytochrome P450 and glucosyltransferase. Ultimately, a preliminary betalain biosynthetic pathway for pitaya was proposed based on betalain analyses, gene expression profiles and published documents.

  20. A secreted Ustilago maydis effector promotes virulence by targeting anthocyanin biosynthesis in maize.

    Science.gov (United States)

    Tanaka, Shigeyuki; Brefort, Thomas; Neidig, Nina; Djamei, Armin; Kahnt, Jörg; Vermerris, Wilfred; Koenig, Stefanie; Feussner, Kirstin; Feussner, Ivo; Kahmann, Regine

    2014-01-01

    The biotrophic fungus Ustilago maydis causes smut disease in maize with characteristic tumor formation and anthocyanin induction. Here, we show that anthocyanin biosynthesis is induced by the virulence promoting secreted effector protein Tin2. Tin2 protein functions inside plant cells where it interacts with maize protein kinase ZmTTK1. Tin2 masks a ubiquitin-proteasome degradation motif in ZmTTK1, thus stabilizing the active kinase. Active ZmTTK1 controls activation of genes in the anthocyanin biosynthesis pathway. Without Tin2, enhanced lignin biosynthesis is observed in infected tissue and vascular bundles show strong lignification. This is presumably limiting access of fungal hyphae to nutrients needed for massive proliferation. Consistent with this assertion, we observe that maize brown midrib mutants affected in lignin biosynthesis are hypersensitive to U. maydis infection. We speculate that Tin2 rewires metabolites into the anthocyanin pathway to lower their availability for other defense responses. DOI: http://dx.doi.org/10.7554/eLife.01355.001.

  1. BnWRI1 coordinates fatty acid biosynthesis and photosynthesis pathways during oil accumulation in rapeseed.

    Science.gov (United States)

    Wu, Xue-Long; Liu, Zhi-Hong; Hu, Zhang-Hua; Huang, Rui-Zhi

    2014-06-01

    Photosynthesis in "green" seeds, such as rapeseed, soybean, and Arabidopsis, plays a substantial role in the improved efficiency of oil accumulation. However, the molecular mechanism underpinning the coordinated expression of fatty acid (FA) biosynthesis- and photosynthesis-related genes in such developing seeds remains to be elucidated. Here, we found that seed-specific overexpression of BnWRI1, a WRI1 homolog from rapeseed (Brassica napus cv. ZGY2), results in enhanced chlorophyll content in developing seeds and increased oil content and seed mass in matured seeds. BnWRI1 was co-expressed with BnBCCP and BnCAB, two marker genes of FA biosynthesis and photosynthesis during seed development, respectively. Overexpression of BnWRI1 increased expression of both marker genes. Further, the nuclear-localized BnWRI1 protein was found to act as a transcription activator. It could bind to the GT1-element and/or GCC-box, which are widespread in the upstream regions of genes involved in FA biosynthesis and photosynthesis pathways. Accordingly, BnWRI1 could interact with promoters of BCCP2 and LHB1B2 in vivo. These results suggested that BnWRI1 may coordinate FA biosynthesis and photosynthesis pathways in developing seeds via directly stimulating expression of GT1-element and/or GCC-box containing genes.

  2. [The effect of beta-ionine on biosynthesis of carotenes by Actinomyces chrysomallus var. carotenoides].

    Science.gov (United States)

    Sverdlova, A N; Alekseeva, L N; Nefelova, M V

    1977-01-01

    Biosynthesis of carotenoids by a growing culture of Actinomyces chrysomallus var. carotenoides is totally inhibited by beta-ionone added at different concentrations, at various time of the cultural growth, and in various combinations with oil. The inhibition of carotenoid synthesis by beta-ionone is of a specific character since the biomass growth under the same conditions does not increase.

  3. Evolution of the biosynthesis of the branched-chain amino acids

    Science.gov (United States)

    Keefe, Anthony D.; Lazcano, Antonio; Miller, Stanley L.

    1995-06-01

    The origin of the biosynthetic pathways for the branched-chain amino acids cannot be understood in terms of the backwards development of the present acetolactate pathway because it contains unstable intermediates. We propose that the first biosynthesis of the branched-chain amino acids was by the reductive carboxylation of short branched chain fatty acids giving keto acids which were then transaminated. Similar reaction sequences mediated by nonspecific enzymes would produce serine and threonine from the abundant prebiotic compounds glycolic and lactic acids. The aromatic amino acids may also have first been synthesized in this way, e.g. tryptophan from indole acetic acid. The next step would have been the biosynthesis of leucine from α-ketoisovaleric acid. The acetolactate pathway developed subsequently. The first version of the Krebs cycle, which was used for amino acid biosynthesis, would have been assembled by making use of the reductive carboxylation and leucine biosynthesis enzymes, and completed with the development of a single new enzyme, succinate dehydrogenase. This evolutionary scheme suggests that there may be limitations to inferring the origins of metabolism by a simple back extrapolation of current pathways.

  4. Evolution of the biosynthesis of the branched-chain amino acids

    Science.gov (United States)

    Keefe, Anthony D.; Lazcano, Antonio; Miller, Stanley L.

    1995-01-01

    The origins of the biosynthetic pathways for the branched-chain amino acids cannot be understood in terms of the backwards development of the present acetolactate pathway because it contains unstable intermediates. We propose that the first biosynthesis of the branched-chain amino acids was by the reductive carboxylation of short branched chain fatty acids giving keto acids which were then transaminated. Similar reaction sequences mediated by nonspecific enzymes would produce serine and threomine from the abundant prebiotic compounds glycolic and lactic acids. The aromatic amino acids may also have first been synthesized in this way, e.g. tryptophan from indole acetic acid. The next step would have been the biosynthesis of leucine from alpha-ketoisovalerc acid. The acetolactate pathway developed subsequently. The first version of the Krebs cycle, which was used for amino acid biosynthesis, would have been assembled by making use fo the reductive carboxylation and leucine biosynthesis enzymes, and completed with the development of a single new enzyme, succinate dehydrogenase. This evolutionary scheme suggests that there may be limitations to inferring the origins of metabolism by a simple back extrapolation of current pathways.

  5. Regulation of ferulate-5-hydroxylase expression in Arabidopsis in the context of sinapate ester biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ruegger, M.; Meyer, K.; Cusumano, J.C.; Chapple, C. [Purdue Univ., West Lafayette, IN (United States). Dept. of Biochemistry

    1999-01-01

    Sinapic acid is an intermediate in syringyl lignin biosynthesis in angiosperms, and in some taxa serves as a precursor for soluble secondary metabolites. The biosynthesis and accumulation of the sinapate esters sinapoylglucose, sinapolymalate, and sinapolycholine are developmentally regulated in Arabidopsis and other members of the Brassicaceae. The FAH1 locus of Arabidopsis encodes the enzyme ferulate-5-hydroxylase (F5H), which catalyzes the rate-limiting step in syringyl lignin biosynthesis and is required for the production of sinapate esters. Here the authors show that F5H expression parallels sinapate ester accumulation in developing siliques and seedlings, but is not rate limiting for their biosynthesis. RNA gel-blot analysis indicated that the tissue-specific and developmentally regulated expression of F5H mRNA is distinct from that of other phenylpropanoid genes. Efforts to identify constructs capable of complementing the sinapate ester-deficient phenotype of fah1 mutants demonstrated that F5H expression in leaves is dependent on sequences 3{prime} of the F5H coding region. In contrast, the positive regulatory function of the downstream region is not required for F5H transcript or sinapolycholine accumulation in embryos.

  6. BnWRI1 coordinates fatty acid biosynthesis and photosynthesis pathways during oil accumulation in rapeseed

    Institute of Scientific and Technical Information of China (English)

    Xue-Long Wu; Zhi-Hong Liu; Zhang-Hua Hu; Rui-Zhi Huang

    2014-01-01

    Photosynthesis in“green”seeds, such as rapeseed, soybean, and Arabidopsis, plays a substantial role in the improved efficiency of oil accumulation. However, the molecular mecha-nism underpinning the coordinated expression of fatty acid (FA) biosynthesis-and photosynthesis-related genes in such develop-ing seeds remains to be elucidated. Here, we found that seed-specific overexpression of BnWRI1, a WRI1 homolog from rapeseed (Brassica napus cv. ZGY2), results in enhanced chlorophyl content in developing seeds and increased oil content and seed mass in matured seeds. BnWRI1 was co-expressed with BnBCCP and BnCAB, two marker genes of FA biosynthesis and photosynthesis during seed development, respectively. Over-expression of BnWRI1 increased expression of both marker genes. Further, the nuclear-localized BnWRI1 protein was found to act as a transcription activator. It could bind to the GT1-element and/or GCC-box, which are widespread in the upstream regions of genes involved in FA biosynthesis and photosynthesis pathways. Accordingly, BnWRI1 could interact with promoters of BCCP2 and LHB1B2 in vivo. These results suggested that BnWRI1 may coordinate FA biosynthesis and photosynthesis pathways in developing seeds via directly stimulating expression of GT1-element and/or GCC-box containing genes.

  7. Molecular characterization of genes encoding leucoanthocyanidin reductase involved in proanthocyanidin biosynthesis in apple

    Directory of Open Access Journals (Sweden)

    Yuepeng eHan

    2015-04-01

    Full Text Available Proanthocyanidins (PAs are the major component of phenolics in apple, but mechanisms involved in PA biosynthesis remain unclear. Here, the relationship between the PA biosynthesis and the expression of genes encoding leucoanthocyanidin reductase (LAR and anthocyanidin reductase (ANR was investigated in fruit skin of one apple cultivar and three crabapples. Transcript levels of LAR1 and ANR2 genes were significantly correlated with the contents of catechin and epicatechin, respectively, which suggests their active roles in PA synthesis. Surprisingly, transcript levels for both LAR1 and LAR2 genes were almost undetectable in two crabapples that accumulated both flavan-3-ols and PAs. This contradicts the previous finding that LAR1 gene is a strong candidate regulating the accumulation of metabolites such as epicatechin and PAs in apple. Ectopic expression of apple MdLAR1 gene in tobacco suppresses expression of the late genes in anthocyanin biosynthetic pathway, resulting in loss of anthocyanin in flowers. Interestingly, a decrease in PA biosynthesis was also observed in flowers of transgenic tobacco plants overexpressing the MdLAR1 gene, which could be attributed to decreased expression of both the NtANR1 and NtANR2 genes. Our study not only confirms the in vivo function of apple LAR1 gene, but it is also helpful for understanding the mechanism of PA biosynthesis.

  8. Modeling and optimization of a multi-product biosynthesis factory for multiple objectives.

    Science.gov (United States)

    Lee, Fook Choon; Pandu Rangaiah, Gade; Lee, Dong-Yup

    2010-05-01

    Genetic algorithms and optimization in general, enable us to probe deeper into the metabolic pathway recipe for multi-product biosynthesis. An augmented model for optimizing serine and tryptophan flux ratios simultaneously in Escherichia coli, was developed by linking the dynamic tryptophan operon model and aromatic amino acid-tryptophan biosynthesis pathways to the central carbon metabolism model. Six new kinetic parameters of the augmented model were estimated with considerations of available experimental data and other published works. Major differences between calculated and reference concentrations and fluxes were explained. Sensitivities and underlying competition among fluxes for carbon sources were consistent with intuitive expectations based on metabolic network and previous results. Biosynthesis rates of serine and tryptophan were simultaneously maximized using the augmented model via concurrent gene knockout and manipulation. The optimization results were obtained using the elitist non-dominant sorting genetic algorithm (NSGA-II) supported by pattern recognition heuristics. A range of Pareto-optimal enzyme activities regulating the amino acids biosynthesis was successfully obtained and elucidated wherever possible vis-à-vis fermentation work based on recombinant DNA technology. The predicted potential improvements in various metabolic pathway recipes using the multi-objective optimization strategy were highlighted and discussed in detail.

  9. Fatty Acid Biosynthesis Pathways in Methylomicrobium buryatense 5G(B1)

    Science.gov (United States)

    Demidenko, Aleksandr; Akberdin, Ilya R.; Allemann, Marco; Allen, Eric E.; Kalyuzhnaya, Marina G.

    2017-01-01

    Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1). Most of the genes homologous to typical Type II fatty acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of fatty acid transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for fatty acid biosynthesis regulation, farE, was identified and studied. Its deletion resulted in drastic changes to the fatty acid profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE-knockout mutants and farE-overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. The gene expression and fatty acid profiles of the different farE-strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph. PMID:28119683

  10. Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and Erythroxylaceae.

    Science.gov (United States)

    Jirschitzka, Jan; Schmidt, Gregor W; Reichelt, Michael; Schneider, Bernd; Gershenzon, Jonathan; D'Auria, John Charles

    2012-06-26

    The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.

  11. Genes involved in long-chain alkene biosynthesis in Micrococcus luteus

    Energy Technology Data Exchange (ETDEWEB)

    Beller, Harry R.; Goh, Ee-Been; Keasling, Jay D.

    2010-01-07

    Aliphatic hydrocarbons are highly appealing targets for advanced cellulosic biofuels, as they are already predominant components of petroleum-based gasoline and diesel fuels. We have studied alkene biosynthesis in Micrococcus luteus ATCC 4698, a close relative of Sarcina lutea (now Kocuria rhizophila), which four decades ago was reported to biosynthesize iso- and anteiso branched, long-chain alkenes. The underlying biochemistry and genetics of alkene biosynthesis were not elucidated in those studies. We show here that heterologous expression of a three-gene cluster from M. luteus (Mlut_13230-13250) in a fatty-acid overproducing E. coli strain resulted in production of long-chain alkenes, predominantly 27:3 and 29:3 (no. carbon atoms: no. C=C bonds). Heterologous expression of Mlut_13230 (oleA) alone produced no long-chain alkenes but unsaturated aliphatic monoketones, predominantly 27:2, and in vitro studies with the purified Mlut_13230 protein and tetradecanoyl-CoA produced the same C27 monoketone. Gas chromatography-time of flight mass spectrometry confirmed the elemental composition of all detected long-chain alkenes and monoketones (putative intermediates of alkene biosynthesis). Negative controls demonstrated that the M. luteus genes were responsible for production of these metabolites. Studies with wild-type M. luteus showed that the transcript copy number of Mlut_13230-13250 and the concentrations of 29:1 alkene isomers (the dominant alkenes produced by this strain) generally corresponded with bacterial population over time. We propose a metabolic pathway for alkene biosynthesis starting with acyl-CoA (or -ACP) thioesters and involving decarboxylative Claisen condensation as a key step, which we believe is catalyzed by OleA. Such activity is consistent with our data and with the homology (including the conserved Cys-His-Asn catalytic triad) of Mlut_13230 (OleA) to FabH (?-ketoacyl-ACP synthase III), which catalyzes decarboxylative Claisen condensation during

  12. Biosynthesis of promatrix metalloproteinase-9/chondroitin sulphate proteoglycan heteromer involves a Rottlerin-sensitive pathway.

    Directory of Open Access Journals (Sweden)

    Nabin Malla

    Full Text Available BACKGROUND: Previously we have shown that a fraction of the matrix metalloproteinase-9 (MMP-9 synthesized by the macrophage cell line THP-1 was bound to a chondroitin sulphate proteoglycan (CSPG core protein as a reduction sensitive heteromer. Several biochemical properties of the enzyme were changed when it was bound to the CSPG. METHODOLOGY/PRINCIPAL FINDINGS: By use of affinity chromatography, zymography, and radioactive labelling, various macrophage stimulators were tested for their effect on the synthesis of the proMMP-9/CSPG heteromer and its components by THP-1 cells. Of the stimulators, only PMA largely increased the biosynthesis of the heteromer. As PMA is an activator of PKC, we determined which PKC isoenzymes were expressed by performing RT-PCR and Western Blotting. Subsequently specific inhibitors were used to investigate their involvement in the biosynthesis of the heteromer. Of the inhibitors, only Rottlerin repressed the biosynthesis of proMMP-9/CSPG and its two components. Much lower concentrations of Rottlerin were needed to reduce the amount of CSPG than what was needed to repress the synthesis of the heteromer and MMP-9. Furthermore, Rottlerin caused a minor reduction in the activation of the PKC isoenzymes δ, ε, θ and υ (PKD3 in both control and PMA exposed cells. CONCLUSIONS/SIGNIFICANCE: The biosynthesis of the proMMP-9/CSPG heteromer and proMMP-9 in THP-1 cells involves a Rottlerin-sensitive pathway that is different from the Rottlerin sensitive pathway involved in the CSPG biosynthesis. MMP-9 and CSPGs are known to be involved in various physiological and pathological processes. Formation of complexes may influence both the specificity and localization of the enzyme. Therefore, knowledge about biosynthetic pathways and factors involved in the formation of the MMP-9/CSPG heteromer may contribute to insight in the heteromers biological function as well as pointing to future targets for therapeutic agents.

  13. Characterization of a C3 Deoxygenation Pathway Reveals a Key Branch Point in Aminoglycoside Biosynthesis.

    Science.gov (United States)

    Lv, Meinan; Ji, Xinjian; Zhao, Junfeng; Li, Yongzhen; Zhang, Chen; Su, Li; Ding, Wei; Deng, Zixin; Yu, Yi; Zhang, Qi

    2016-05-25

    Apramycin is a clinically interesting aminoglycoside antibiotic (AGA) containing a highly unique bicyclic octose moiety, and this octose is deoxygenated at the C3 position. Although the biosynthetic pathways for most 2-deoxystreptamine-containing AGAs have been well characterized, the pathway for apramycin biosynthesis, including the C3 deoxygenation process, has long remained unknown. Here we report detailed investigation of apramycin biosynthesis by a series of genetic, biochemical and bioinformatical studies. We show that AprD4 is a novel radical S-adenosyl-l-methionine (SAM) enzyme, which uses a noncanonical CX3CX3C motif for binding of a [4Fe-4S] cluster and catalyzes the dehydration of paromamine, a pseudodisaccharide intermediate in apramycin biosynthesis. We also show that AprD3 is an NADPH-dependent reductase that catalyzes the reduction of the dehydrated product from AprD4-catalyzed reaction to generate lividamine, a C3' deoxygenated product of paromamine. AprD4 and AprD3 do not form a tight catalytic complex, as shown by protein complex immunoprecipitation and other assays. The AprD4/AprD3 enzyme system acts on different pseudodisaccharide substrates but does not catalyze the deoxygenation of oxyapramycin, an apramycin analogue containing a C3 hydroxyl group on the octose moiety, suggesting that oxyapramycin and apramycin are partitioned into two parallel pathways at an early biosynthetic stage. Functional dissection of the C6 dehydrogenase AprQ shows the crosstalk between different AGA biosynthetic gene clusters from the apramycin producer Streptomyces tenebrarius, and reveals the remarkable catalytic versatility of AprQ. Our study highlights the intriguing chemistry in apramycin biosynthesis and nature's ingenuity in combinatorial biosynthesis of natural products.

  14. Oxidative stress induces the biosynthesis of citrinin by Penicillium verrucosum at the expense of ochratoxin.

    Science.gov (United States)

    Schmidt-Heydt, Markus; Stoll, Dominic; Schütz, Peter; Geisen, Rolf

    2015-01-02

    Penicillium verrucosum is a fungus that can produce ochratoxin A and citrinin, two structurally related nephrotoxic mycotoxins. P. verrucosum usually occurs on wheat but can occasionally also be found in NaCl rich habitats such as salted cheeses or olives, indicating that this fungus can adapt to different environments. The ratio of ochratoxin A to citrinin produced by P. verrucosum is shifted to one of either mycotoxin at the expense of the other dependent on the environmental conditions. High NaCl concentrations shift secondary metabolite biosynthesis towards ochratoxin A production. P. verrucosum copes with NaCl stress by increased ochratoxin A biosynthesis, ensuring chloride homeostasis. Ochratoxin A carries chlorine in its molecule and can excrete chlorine from the cell. It was further shown that the regulation of ochratoxin A by high NaCl conditions is mediated by the HOG MAP kinase signal transduction pathway. Here it is shown that high oxidative stress conditions, evoked for example by increasing concentrations of Cu(2+) cations in the growth medium, shift secondary metabolite biosynthesis of P. verrucosum from ochratoxin A to citrinin. The production of citrinin normalizes the oxidative status of the fungal cell under oxidative stress conditions leading to an adaptation to these environmental conditions and protects against increased oxidative stress caused by increased Cu(2+) concentrations. Moreover citrinin also protects against light of short wavelength, which may also increase the oxidative status of the environment. The biosynthesis of citrinin is apparently regulated by a cAMP/PKA signaling pathway, because increasing amounts of external cAMP reduce citrinin biosynthesis in a concentration dependent manner. These conditions lead to the cross-regulation of the ochratoxin A/citrinin secondary metabolite pair and support the adaptation of P. verrucosum to different environments.

  15. Low-fluence red light increases the transport and biosynthesis of auxin.

    Science.gov (United States)

    Liu, Xing; Cohen, Jerry D; Gardner, Gary

    2011-10-01

    In plants, light is an important environmental signal that induces photomorphogenesis and interacts with endogenous signals, including hormones. We found that light increased polar auxin transport in dark-grown Arabidopsis (Arabidopsis thaliana) and tomato (Solanum lycopersicum) hypocotyls. In tomato, this increase was induced by low-fluence red or blue light followed by 1 d of darkness. It was reduced in phyA, phyB1, and phyB2 tomato mutants and was reversed by far-red light applied immediately after the red or blue light exposure, suggesting that phytochrome is involved in this response. We further found that the free indole-3-acetic acid (IAA) level in hypocotyl regions below the hook was increased by red light, while the level of conjugated IAA was unchanged. Analysis of IAA synthesized from [¹³C]indole or [¹³C]tryptophan (Trp) revealed that both Trp-dependent and Trp-independent IAA biosynthesis were increased by low-fluence red light in the top section (meristem, cotyledons, and hook), and the Trp-independent pathway appears to become the primary route for IAA biosynthesis after red light exposure. IAA biosynthesis in tissues below the top section was not affected by red light, suggesting that the increase of free IAA in this region was due to increased transport of IAA from above. Our study provides a comprehensive view of light effects on the transport and biosynthesis of IAA, showing that red light increases both IAA biosynthesis in the top section and polar auxin transport in hypocotyls, leading to unchanged free IAA levels in the top section and increased free IAA levels in the lower hypocotyl regions.

  16. Transcriptome sequencing and expression analysis of terpenoid biosynthesis genes in Litsea cubeba.

    Directory of Open Access Journals (Sweden)

    Xiao-Jiao Han

    Full Text Available BACKGROUND: Aromatic essential oils extracted from fresh fruits of Litsea cubeba (Lour. Pers., have diverse medical and economic values. The dominant components in these essential oils are monoterpenes and sesquiterpenes. Understanding the molecular mechanisms of terpenoid biosynthesis is essential for improving the yield and quality of terpenes. However, the 40 available L. cubeba nucleotide sequences in the public databases are insufficient for studying the molecular mechanisms. Thus, high-throughput transcriptome sequencing of L. cubeba is necessary to generate large quantities of transcript sequences for the purpose of gene discovery, especially terpenoid biosynthesis related genes. RESULTS: Using Illumina paired-end sequencing, approximately 23.5 million high-quality reads were generated. De novo assembly yielded 68,648 unigenes with an average length of 834 bp. A total of 38,439 (56% unigenes were annotated for their functions, and 35,732 and 25,806 unigenes could be aligned to the GO and COG database, respectively. By searching against the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG, 16,130 unigenes were assigned to 297 KEGG pathways, and 61 unigenes, which contained the mevalonate and 2-C-methyl-D-erythritol 4-phosphate pathways, could be related to terpenoid backbone biosynthesis. Of the 12,963 unigenes, 285 were annotated to the terpenoid pathways using the PlantCyc database. Additionally, 14 terpene synthase genes were identified from the transcriptome. The expression patterns of the 16 genes related to terpenoid biosynthesis were analyzed by RT-qPCR to explore their putative functions. CONCLUSION: RNA sequencing was effective in identifying a large quantity of sequence information. To our knowledge, this study is the first exploration of the L. cubeba transcriptome, and the substantial amount of transcripts obtained will accelerate the understanding of the molecular mechanisms of essential oils biosynthesis. The

  17. Brain modulation of Dufour's gland ester biosynthesis in vitro in the honeybee ( Apis mellifera)

    Science.gov (United States)

    Katzav-Gozansky, Tamar; Hefetz, Abraham; Soroker, Victoria

    2007-05-01

    Caste-specific pheromone biosynthesis is a prerequisite for reproductive skew in the honeybee. Nonetheless, this process is not hardwired but plastic, in that egg-laying workers produce a queen-like pheromone. Studies with Dufour’s gland pheromone revealed that, in vivo, workers’ gland biosynthesis matches the social status of the worker, i.e., sterile workers showed a worker-like pattern whereas fertile workers showed a queen-like pattern (production of the queen-specific esters). However, when incubated in vitro, the gland spontaneously exhibits the queen-like pattern, irrespective of its original worker type, prompting the notion that ester production in workers is under inhibitory control that is queen-dependent. We tested this hypothesis by exposing queen or worker Dufour’s glands in vitro to brain extracts of queens, queenright (sterile) workers and males. Unexpectedly, worker brain extracts activated the queen-like esters biosynthesis in workers’ Dufour’s gland. This stimulation was gender-specific; queen or worker brains demonstrated a stimulatory activity, but male brains did not. Queen gland could not be further stimulated. Bioassays with heated and filtered extracts indicate that the stimulatory brain factor is below 3,000 Da. We suggest that pheromone production in Dufour’s gland is under dual, negative positive control. Under queenright conditions, the inhibitor is released and blocks ester biosynthesis, whereas under queenless conditions, the activator is released, activating ester biosynthesis in the gland. This is consistent with the hypothesis that queenright workers are unequivocally recognized as non-fertile, whereas queenless workers try to become “false queens” as part of the reproductive competition.

  18. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  19. [The role of the promoter and leader sequences of extracellular ribonuclease from Bacillus amyloliquefaciens in regulation of enzyme biosynthesis].

    Science.gov (United States)

    Znamenskaia, L V; Kaiumova, A R; Kharitonova, M A; Vershinina, V I

    2005-01-01

    It is shown that in the medium rich with inorganic phosphate there is a stimulation of biosynthesis of ribonuclease from B. amyloliquefaciens (barnase) by actinomycin D, while biosynthesis of ribonucleases from B. intermedius (binase) and B. pumilus (KNase Bpu) in these conditions was suppressed. Features of biosynthesis of binase and RNase Bpu, directed by the barnase promoter, and also expression of chimeric gene of RNase Bpu with leader peptide of barnase were investigated. It was established that stimulation of synthesis of extracellular ribonuclease from B. amyloliquefaciens in the presence of actinomycin D was defined by structure of leader sequences.

  20. Two Master Switch Regulators Trigger A40926 Biosynthesis in Nonomuraea sp. Strain ATCC 39727

    Science.gov (United States)

    Lo Grasso, Letizia; Maffioli, Sonia; Sosio, Margherita; Bibb, Mervyn; Puglia, Anna Maria

    2015-01-01

    ABSTRACT The actinomycete Nonomuraea sp. strain ATCC 39727 produces the glycopeptide A40926, the precursor of dalbavancin. Biosynthesis of A40926 is encoded by the dbv gene cluster, which contains 37 protein-coding sequences that participate in antibiotic biosynthesis, regulation, immunity, and export. In addition to the positive regulatory protein Dbv4, the A40926-biosynthetic gene cluster encodes two additional putative regulators, Dbv3 and Dbv6. Independent mutations in these genes, combined with bioassays and liquid chromatography-mass spectrometry (LC-MS) analyses, demonstrated that Dbv3 and Dbv4 are both required for antibiotic production, while inactivation of dbv6 had no effect. In addition, overexpression of dbv3 led to higher levels of A40926 production. Transcriptional and quantitative reverse transcription (RT)-PCR analyses showed that Dbv4 is essential for the transcription of two operons, dbv14-dbv8 and dbv30-dbv35, while Dbv3 positively controls the expression of four monocistronic transcription units (dbv4, dbv29, dbv36, and dbv37) and of six operons (dbv2-dbv1, dbv14-dbv8, dbv17-dbv15, dbv21-dbv20, dbv24-dbv28, and dbv30-dbv35). We propose a complex and coordinated model of regulation in which Dbv3 directly or indirectly activates transcription of dbv4 and controls biosynthesis of 4-hydroxyphenylglycine and the heptapeptide backbone, A40926 export, and some tailoring reactions (mannosylation and hexose oxidation), while Dbv4 directly regulates biosynthesis of 3,5-dihydroxyphenylglycine and other tailoring reactions, including the four cross-links, halogenation, glycosylation, and acylation. IMPORTANCE This report expands knowledge of the regulatory mechanisms used to control the biosynthesis of the glycopeptide antibiotic A40926 in the actinomycete Nonomuraea sp. strain ATCC 39727. A40926 is the precursor of dalbavancin, approved for treatment of skin infections by Gram-positive bacteria. Therefore, understanding the regulation of its biosynthesis

  1. Short-day signals are crucial for the induction of anthocyanin biosynthesis in Begonia semperflorens under low temperature condition.

    Science.gov (United States)

    Zhang, Kai Ming; Wang, Jia Wan; Guo, Mei Li; Du, Wen Li; Wu, Rong Hua; Wang, Xian

    2016-10-01

    The leaves of Begonia semperflorens accumulate anthocyanins and turn red in autumn in sub-temperate areas. This induction of anthocyanin biosynthesis in autumn has been attributed to the effects of low temperature, but the effects of different light regimes on this process are still being debated. In the present work, short days were found to be necessary for anthocyanin biosynthesis at low temperature. Under the same low-temperature conditions, Begonia seedlings grown under the short-day condition accumulated more carbohydrates and abscisic acid (ABA), which both induce anthocyanin biosynthesis. However, fewer carbohydrates and more gibberellin (GA) accumulated under the long-day conditions to maintain growth, which blocked anthocyanin biosynthesis and resulted in a lack of increases in the activities of dihydroflavonol 4-reductase (DFR) and flavonoid-3-O-glucosyl transferase (UFGT). Consequently, carbon flux, which was altered due to the blockade of anthocyanin synthesis, was channelled into the production of quercetin and phenolic acids but not lignin.

  2. Interleukin 1 dose-dependently affects the biosynthesis of (pro)insulin in isolated rat islets of Langerhans

    DEFF Research Database (Denmark)

    Spinas, G A; Hansen, B S; Linde, S

    1987-01-01

    Human crude and recombinant interleukin 1 (IL-1) was found to dose- and time-dependently affect the biosynthesis of (pro)insulin in isolated rat islets of Langerhans. Incubation of rat islets with either 0.5 U/ml or 5 U/ml of crude IL-1 for 1 h had no detectable effect on (pro)insulin biosynthesis....... After 24 hours of exposure 0.5 U/ml of crude or 0.6 ng/ml of recombinant IL-1 (beta) increased the (pro)insulin biosynthesis by 42% and 58%, respectively, whereas a 10-fold greater concentration of IL-1 decreased the (pro)insulin biosynthesis by 74% and 89%, respectively. The increase in (pro...

  3. Distribution of colored carotenoids between light-harvesting complexes in the process of recovering carotenoid biosynthesis in Ectothiorhodospira haloalkaliphila cells.

    Science.gov (United States)

    Ashikhmin, Aleksandr; Makhneva, Zoya; Bolshakov, Maksim; Moskalenko, Andrey

    2014-12-01

    The processes of recovering colored-carotenoid (Car) biosynthesis in Car-less cells of the purple sulfur bacterium Ectothiorhodospira haloalkaliphila grown with diphenylamine (DPA-cells) have been studied. It has been found that (1) the rate of recovering colored-Car biosynthesis in the lag-phase is far ahead of the growth rate of the cells themselves; (2) several Cars (ζ-carotene, neurosporene etc.) act as intermediates in Car biosynthesis; (3) because filling the "empty" Car pockets in the LH1-RC complexes is faster than in LH2, available spirilloxanthin is preferentially incorporated into the nascent LH1-RC core particles; (4) as a consequence of the resulting lack of spirilloxanthin availability, the biosynthetic intermediates (anhydrorhodovibrin, rhodopin and lycopene) fill the empty nascent LH2 Car pockets. In the present report, we further discuss the process of colored Car incorporation into LH complexes during the recovery of Car biosynthesis in the DPA-cells of Ect.haloalkaliphila.

  4. Nitric oxide:A potential key point of the signaling network leading to plant secondary metabolite biosynthesis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The endogenous signaling network of plants plays important roles in mediating the exogenous factor-induced biosynthesis of secondary metabolites.Nitric oxide (NO) has emerged as a key signaling molecule in plants recently.Numerous studies demonstrated that the main signaling molecules such as salicylic acid(SA),jasmonic acid (JA),reactive oxygen species(ROS),and NO were not only involved in regulating plant secondary metabolite biosynthesis but also interacted to form a complex signaling network by mutual inhibition and/or synergy.The recent progress in the signal network of plant secondary metabolite biosynthesis has been discussed in this paper.Furthermore,we propose a hypothetical model to show that NO might act as a potential molecular switch in the stgnaling network leading to plant secondary metabolite biosynthesis.

  5. Ionic liquids as novel solvents for biosynthesis of octenyl succinic anhydride-modified waxy maize starch.

    Science.gov (United States)

    Li, Dandan; Zhang, Xiwen; Tian, Yaoqi

    2016-05-01

    Biosynthesis of octenyl succinic anhydride (OSA) starch was investigated using ionic liquids (ILs) as reaction media. Waxy maize starch was pretreated in 1-butyl-3-methylimidazolium chlorine and then esterified with OSA in 1-octyl-3-methylimidazolium nitrate by using Novozyme 435 as catalyst. The degree of substitution of OSA starch reached 0.0130 with 5 wt% starch concentration and 1 wt% lipase dosage based on ILs weight at 50 °C for 3h. The formation of OSA starch was confirmed by fourier transform infrared spectroscopy. Scanning electron microscopy and X-ray diffraction revealed that the morphology and crystal structure of starch were significantly destroyed. Thermogravimetric analysis showed that esterification decreased the thermal stability of starch. The successful lipase-catalyzed synthesis of OSA starch in ILs suggests that ILs are potential replacement of traditional organic solvents for starch ester biosynthesis.

  6. In situ recovery of lycopene during biosynthesis with recombinant Escherichia coli.

    Science.gov (United States)

    Yoon, Ko-Woon; Doo, Eun-Hee; Kim, Seon-Won; Park, Jin-Byung

    2008-06-30

    Lycopene is produced by recombinant Escherichia coli expressing genes to encode for the lycopene biosynthesis. However, the productivity of lycopene seemed to be limited by many factors including product toxicity. In the present study, we have investigated physiology of recombinant E. coli during biosynthesis and in situ recovery of lycopene based on an organic/aqueous two-phase system. Lycopene, the 40-carbon molecule product, was little extracted from recombinant E. coli cells to octane or decane phase. However, partial digestion of cell walls with lysozyme promoted extraction of lycopene into the organic phases. Engineering of an organic/aqueous two-phase system allowed recombinant E. coli cells to produce ca. 40% larger amount of lycopene compared to that in a conventional aqueous single-phase system. Optimization of the in situ product recovery process will lead to further increase of product concentration and productivity.

  7. Site of lupanine and sparteine biosynthesis in intact plants and in vitro organ cultures

    Energy Technology Data Exchange (ETDEWEB)

    Wink, M.

    (/sup 14/C)Cadaverine was applied to leaves of Lupinus polyphyllus, L. albus, L. angustifolius, L. perennis, L. mutabilis, L. pubescens, and L. hartwegii and it was preferentially incorporated into lupanine. In Lupinus arboreus sparteine was the main labelled alkaloid, in L. hispanicus it was lupanine. A pulse chase experiment with L. angustifolius and L. arboreus showed that the incorporation of cadaverine into lupanine and sparteine was transient with a maximum between 8 and 20 h. Only leaflets and chlorophyllous petioles showed active alkaloid biosynthesis, whereas no incorporation of cadaverine into lupanine was observed in roots. Using in vitro organ cultures of Lupinus polyphyllus, L. succulentus, L. subcarnosus, Cytisus scoparius and Laburnum anagyroides the inactivity of roots was confirmed. Therefore, the green aerial parts are the major site of alkaloid biosynthesis in lupins and in other legumes.

  8. The Tat protein export pathway and its role in cyanobacterial metalloprotein biosynthesis.

    Science.gov (United States)

    Barnett, James P; Robinson, Colin; Scanlan, David J; Blindauer, Claudia A

    2011-12-01

    The Tat pathway is a common protein translocation system that is found in the bacterial cytoplasmic membrane, as well as in the cyanobacterial and plant thylakoid membranes. It is unusual in that the Tat pathway transports fully folded, often metal cofactor-containing proteins across these membranes. In bacteria, the Tat pathway plays an important role in the biosynthesis of noncytoplasmic metalloproteins. By compartmentalizing protein folding to the cytoplasm, the potentially aberrant binding of non-native metal ions to periplasmic proteins is avoided. To date, most of our understanding of Tat function has been obtained from studies using Escherichia coli as a model organism but cyanobacteria have an extra layer of complexity with proteins targeted to both the cytoplasmic and thylakoid membranes. We examine our current understanding of the Tat pathway in cyanobacteria and its role in metalloprotein biosynthesis.

  9. Biosynthesis of flat silver nanoflowers: from Flos Magnoliae Officinalis extract to simulation solution

    Science.gov (United States)

    Jing, Xiaolian; Huang, Jiale; Wu, Lingfeng; Sun, Daohua; Li, Qingbiao

    2014-03-01

    Flat Ag nanoflowers were directly synthesized from the bioreduction of AgNO3 using Flos Magnoliae Officinalis extract without any additional stabilizer or protective agent at room temperature. Effects of concentrations of the Flos Magnoliae Officinalis extract on the Ag nanostructures were investigated. The main components containing flavone, polyphenol, protein, and reducing sugar in the plant extract were thoroughly determined before and after the reaction, and the dialysis experiments were also conducted. The results of components analysis and dialysis showed that gallic acid representing polyphenols played an important role in the biosynthesis of silver nanoplates. Trisodium citrate combined gallic acid solution, instead of Flos Magnoliae Officinalis extract, was employed and successfully simulated the biosynthesis process of the flat Ag nanoflowers.

  10. Comparative genomics of NAD(P) biosynthesis and novel antibiotic drug targets.

    Science.gov (United States)

    Bi, Jicai; Wang, Honghai; Xie, Jianping

    2011-02-01

    NAD(P) is an indispensable cofactor for all organisms and its biosynthetic pathways are proposed as promising novel antibiotics targets against pathogens such as Mycobacterium tuberculosis. Six NAD(P) biosynthetic pathways were reconstructed by comparative genomics: de novo pathway (Asp), de novo pathway (Try), NmR pathway I (RNK-dependent), NmR pathway II (RNK-independent), Niacin salvage, and Niacin recycling. Three enzymes pivotal to the key reactions of NAD(P) biosynthesis are shared by almost all organisms, that is, NMN/NaMN adenylyltransferase (NMN/NaMNAT), NAD synthetase (NADS), and NAD kinase (NADK). They might serve as ideal broad spectrum antibiotic targets. Studies in M. tuberculosis have in part tested such hypothesis. Three regulatory factors NadR, NiaR, and NrtR, which regulate NAD biosynthesis, have been identified. M. tuberculosis NAD(P) metabolism and regulation thereof, potential drug targets and drug development are summarized in this paper.

  11. Effect of oxidoreduction potential on aroma biosynthesis by lactic acid bacteria in nonfat yogurt.

    Science.gov (United States)

    Martin, F; Cachon, R; Pernin, K; De Coninck, J; Gervais, P; Guichard, E; Cayot, N

    2011-02-01

    The aim of this study was to investigate the effect of oxidoreduction potential (Eh) on the biosynthesis of aroma compounds by lactic acid bacteria in non-fat yogurt. The study was done with yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus. The Eh was modified by the application of different gaseous conditions (air, nitrogen, and nitrogen/hydrogen). Acetaldehyde, dimethyl sulfide, diacetyl, and pentane-2,3-dione, as the major endogenous odorant compounds of yogurt, were chosen as tracers for the biosynthesis of aroma compounds by lactic acid bacteria. Oxidative conditions favored the production of acetaldehyde, dimethyl sulfide, and diketones (diacetyl and pentane-2,3-dione). The Eh of the medium influences aroma production in yogurt by modifying the metabolic pathways of Lb. bulgaricus and Strep. thermophilus. The use of Eh as a control parameter during yogurt production could permit the control of aroma formation.

  12. Understanding the control of acyl flux through the lipid metabolic network of plant oil biosynthesis.

    Science.gov (United States)

    Bates, Philip D

    2016-09-01

    Plant oil biosynthesis involves a complex metabolic network with multiple subcellular compartments, parallel pathways, cycles, and pathways that have a dual function to produce essential membrane lipids and triacylglycerol. Modern molecular biology techniques provide tools to alter plant oil compositions through bioengineering, however with few exceptions the final composition of triacylglycerol cannot be predicted. One reason for limited success in oilseed bioengineering is the inadequate understanding of how to control the flux of fatty acids through various fatty acid modification, and triacylglycerol assembly pathways of the lipid metabolic network. This review focuses on the mechanisms of acyl flux through the lipid metabolic network, and highlights where uncertainty resides in our understanding of seed oil biosynthesis. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.

  13. Role of EctR as transcriptional regulator of ectoine biosynthesis genes in Methylophaga thalassica.

    Science.gov (United States)

    Mustakhimov, I I; Reshetnikov, A S; Fedorov, D N; Khmelenina, V N; Trotsenko, Y A

    2012-08-01

    In the halophilic aerobic methylotrophic bacterium Methylophaga thalassica, the genes encoding the enzymes for biosynthesis of the osmoprotectant ectoine were shown to be located in operon ectABC-ask. Transcription of the ect-operon was started from the two promoters homologous to the σ(70)-dependent promoter of Escherichia coli and regulated by protein EctR, whose encoding gene, ectR, is transcribed from three promoters. Genes homologous to ectR of methylotrophs were found in clusters of ectoine biosynthesis genes in some non-methylotrophic halophilic bacteria. EctR proteins of methylotrophic and heterotrophic halophiles belong to the MarR-family of transcriptional regulators but form a separate branch on the phylogenetic tree of the MarR proteins.

  14. Total biosynthesis of opiates by stepwise fermentation using engineered Escherichia coli.

    Science.gov (United States)

    Nakagawa, Akira; Matsumura, Eitaro; Koyanagi, Takashi; Katayama, Takane; Kawano, Noriaki; Yoshimatsu, Kayo; Yamamoto, Kenji; Kumagai, Hidehiko; Sato, Fumihiko; Minami, Hiromichi

    2016-02-05

    Opiates such as morphine and codeine are mainly obtained by extraction from opium poppies. Fermentative opiate production in microbes has also been investigated, and complete biosynthesis of opiates from a simple carbon source has recently been accomplished in yeast. Here we demonstrate that Escherichia coli serves as an efficient, robust and flexible platform for total opiate synthesis. Thebaine, the most important raw material in opioid preparations, is produced by stepwise culture of four engineered strains at yields of 2.1 mg l(-1) from glycerol, corresponding to a 300-fold increase from recently developed yeast systems. This improvement is presumably due to strong activity of enzymes related to thebaine synthesis from (R)-reticuline in E. coli. Furthermore, by adding two genes to the thebaine production system, we demonstrate the biosynthesis of hydrocodone, a clinically important opioid. Improvements in opiate production in this E. coli system represent a major step towards the development of alternative opiate production systems.

  15. Tilting Plant Metabolism for Improved Metabolite Biosynthesis and Enhanced Human Benefit

    Directory of Open Access Journals (Sweden)

    Bhekumthetho Ncube

    2015-07-01

    Full Text Available The immense chemical diversity of plant-derived secondary metabolites coupled with their vast array of biological functions has seen this group of compounds attract considerable research interest across a range of research disciplines. Medicinal and aromatic plants, in particular, have been exploited for this biogenic pool of phytochemicals for products such as pharmaceuticals, fragrances, dyes, and insecticides, among others. With consumers showing increasing interests in these products, innovative biotechnological techniques are being developed and employed to alter plant secondary metabolism in efforts to improve on the quality and quantity of specific metabolites of interest. This review provides an overview of the biosynthesis for phytochemical compounds with medicinal and other related properties and their associated biological activities. It also provides an insight into how their biosynthesis/biosynthetic pathways have been modified/altered to enhance production.

  16. Separation of impurities in diazinon preparations and their effect on porphyrin biosynthesis in tissue culture.

    Science.gov (United States)

    Nichol, A W; Elsbury, S; Elder, G H; Jackson, A H; Rao, K R

    1982-03-15

    The impurities present in commercial diazinon preparations have been examined by high performance liquid chromatography with particular reference to the ability of these compounds to cause porphyrin accumulation in cultures of chicken embryo liver cells. Diazinon and its impurities are readily separated on 10 micron Partisil using cyclohexane-dioxan mixtures. The main impurities are tetraethylpyrophosphate, sulphotetraethylpyrophosphate, 2-isopropyl-6-methylpyrimid-4-one, 2-isopropyl-6-methylpyrimidin-4-thione, and 2-isopropyl-4-ethylthio-6-methylpyrimidine. A previously unreported impurity, 2-isopropyl-6-methyl-4-S-pyrimidinyl diethylthiophosphate (isodiazinon), was also detected. Both diazinon and isodiazinon cause accumulation of coproporphyrin in cultures of chicken embryo liver cells. Isodiazinon has a greater effect on porphyrin biosynthesis in the cultures than has diazinon. It is suggested that the point of interference with porphyrin biosynthesis is towards the end of the pathway.

  17. Isoprenoid biosynthesis. Metabolite profiling of peppermint oil gland secretory cells and application to herbicide target analysis.

    Science.gov (United States)

    Lange, B M; Ketchum, R E; Croteau, R B

    2001-09-01

    Two independent pathways operate in plants for the synthesis of isopentenyl diphosphate and dimethylallyl diphosphate, the central intermediates in the biosynthesis of all isoprenoids. The mevalonate pathway is present in the cytosol, whereas the recently discovered mevalonate-independent pathway is localized to plastids. We have used isolated peppermint (Mentha piperita) oil gland secretory cells as an experimental model system to study the effects of the herbicides fosmidomycin, phosphonothrixin, methyl viologen, benzyl viologen, clomazone, 2-(dimethylamino)ethyl diphosphate, alendronate, and pamidronate on the pools of metabolites related to monoterpene biosynthesis via the mevalonate-independent pathway. A newly developed isolation protocol for polar metabolites together with an improved separation and detection method based on liquid chromatography-mass spectrometry have allowed assessment of the enzyme targets for a number of these herbicides.

  18. [Effect of pyruvate and valine on avermectin biosynthesis by Streptomyces avermitilis UCM Ac-2179].

    Science.gov (United States)

    Biliavs'ka, L O; Kozyryts'ka, V Ie; Valahurova, O V; Iutyns'ka, H O

    2007-01-01

    Pyruvate and valine have been studied for their effect on avermectin biosynthesis by the mutant strain Streptomyces avermitilis UCM Ac-2179. Valine in concentrations 0.5, 1.0 and 1.5 g/l inhibited the antibiotic synthesis. The same concentrations of pyruvate increased the avermectin production 2-2.5 times. The strain cultivated in the mineral medium produced during trophophase some lipids which were not almost revealed during idiophase when avermectin active synthesis took place. The authors make a supposition about the ways of avermectin synthesis by S. avermitilis UCM Ac-2179: the antibiotic biosynthesis can proceed not only through pyruvate transformation but, to a considerable extent, at the expense of using fatty acids which are produced by the culture.

  19. [Effect on production of avermectins of spore pigment biosynthesis in Streptomyces avermitilis NRRL8165].

    Science.gov (United States)

    Zhu, Juanjuan; Tao, Meifeng

    2008-10-01

    The flanking fragments of the whiE(a) gene cluster was PCR amplified, cloned and used to construct the gene replacement plasmid pHL643. pHL643 was conjugated into Streptomyces avermitilis NRRL8165 followed by screening for double crossover event, yielding three apramycin resistance and thiostrepton sensitive isolates named ZJ1, ZJ2 and ZJ3, which were deficient in biosynthesis of the grey spore pigment. The whiE(a) gene replacement of these isolates was confirmed by Southern hybridization. Fermentation of the mutant strains in shaking flasks and HPLC analyses showed that the production of avermectins increased by 47% compared with that of the wild type, indicating that the spore pigment biosynthesis competes with the avermectins biosynthetic pathway.

  20. The expanding roles of c-di-GMP in the biosynthesis of exopolysaccharides and secondary metabolites.

    Science.gov (United States)

    Liang, Zhao-Xun

    2015-05-01

    The cyclic dinucleotide c-di-GMP has emerged in the last decade as a prevalent intracellular messenger that orchestrates the transition between the motile and sessile lifestyles of many bacterial species. The motile-to-sessile transition is often associated with the formation of extracellular matrix-encased biofilm, an organized community of bacterial cells that often contributes to antibiotic resistance and host-pathogen interaction. It is increasingly clear that c-di-GMP controls motility, biofilm formation and bacterial pathogenicity partially through regulating the production of exopolysaccharides (EPS) and small-molecule secondary metabolites. This review summarizes our current understanding of the regulation of EPS biosynthesis by c-di-GMP in a diversity of bacterial species and highlights the emerging role of c-di-GMP in the biosynthesis of small-molecule secondary metabolites.

  1. The last step in cocaine biosynthesis is catalyzed by a BAHD acyltransferase.

    Science.gov (United States)

    Schmidt, Gregor Wolfgang; Jirschitzka, Jan; Porta, Tiffany; Reichelt, Michael; Luck, Katrin; Torre, José Carlos Pardo; Dolke, Franziska; Varesio, Emmanuel; Hopfgartner, Gérard; Gershenzon, Jonathan; D'Auria, John Charles

    2015-01-01

    The esterification of methylecgonine (2-carbomethoxy-3β-tropine) with benzoic acid is the final step in the biosynthetic pathway leading to the production of cocaine in Erythoxylum coca. Here we report the identification of a member of the BAHD family of plant acyltransferases as cocaine synthase. The enzyme is capable of producing both cocaine and cinnamoylcocaine via the activated benzoyl- or cinnamoyl-Coenzyme A thioesters, respectively. Cocaine synthase activity is highest in young developing leaves, especially in the palisade parenchyma and spongy mesophyll. These data correlate well with the tissue distribution pattern of cocaine as visualized with antibodies. Matrix-assisted laser-desorption ionization mass spectral imaging revealed that cocaine and cinnamoylcocaine are differently distributed on the upper versus lower leaf surfaces. Our findings provide further evidence that tropane alkaloid biosynthesis in the Erythroxylaceae occurs in the above-ground portions of the plant in contrast with the Solanaceae, in which tropane alkaloid biosynthesis occurs in the roots.

  2. Natures balancing act: examining biosynthesis de novo, recycling and processing damaged vitamin B metabolites.

    Science.gov (United States)

    Colinas, Maite; Fitzpatrick, Teresa B

    2015-06-01

    Plants use B vitamin compounds as cofactors for metabolism. Biosynthesis de novo of these metabolites in plants is almost fully elucidated. However, salvaging of precursors as well as cofactor derivatives is only being unraveled. Furthermore, processing of these compounds when damaged by cellular activities to prevent deleterious effects on metabolism is emerging. Recent investigations indicate that the role of B vitamins goes beyond metabolism and are being linked with epigenetic traits, specific developmental cues, the circadian clock, as well as abiotic and biotic stress responses. More in depth investigations on the regulation of the provision of these compounds through biosynthesis de novo, salvage and transport is suggesting that plants may share the cost of this load by division of labor.

  3. The Continuing Development of E. coli as a Heterologous Host for Complex Natural Product Biosynthesis.

    Science.gov (United States)

    Zhang, Haoran; Fang, Lei; Osburne, Marcia S; Pfeifer, Blaine A

    2016-01-01

    Heterologous biosynthesis of natural products is meant to enable access to the vast array of valuable properties associated with these compounds. Often motivated by limitations inherent in native production hosts, the heterologous biosynthetic process begins with a candidate host regarded as technically advanced relative to original producing organisms. Given this requirement, E. coli has been a top choice for heterologous biosynthesis attempts as associated recombinant tools emerged and continue to develop. However, success requires overcoming challenges associated with natural product formation, including complex biosynthetic pathways and the need for metabolic support. These two challenges have been heavily featured in cellular engineering efforts completed to position E. coli as a viable surrogate host. This chapter outlines steps taken to engineer E. coli with an emphasis on genetic manipulations designed to support the heterologous production of polyketide, nonribosomal peptide, and similarly complex natural products.

  4. An Integrative Analysis of the Effects of Auxin on Jasmonic Acid Biosynthesis in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Jun Liu; Xiu-Jie Wang

    2006-01-01

    Auxin and jasmonic acid (JA) are two plant phytohormones that both participate in the regulation of many developmental processes. Jasmonic acid also plays important roles in plant stress response reactions.Although extensive investigations have been undertaken to study the biological functions of auxin and JA,little attention has been paid to the cross-talk between their regulated pathways. In the few available reports examining the effects of auxin on the expression of JA or JA-responsive genes, both synergetic and antagonistic results have been found. To further investigate the relationship between auxin and JA, we adopted an integrative method that combines microarray expression data with pathway information to study the behavior of the JA biosynthesis pathway under auxin treatment. Our results showed an overall downregulation of genes involved in JA biosynthesis, providing the first report of a relationship between auxin and the JA synthesis pathway in Arabidopsis seedlings.

  5. Expression analysis for genes involved in arachidonic acid biosynthesis in Mortierella alpina CBS 754.68

    Directory of Open Access Journals (Sweden)

    Hamid-Reza Samadlouie

    2014-06-01

    Full Text Available The time courses for production of fungal biomass, lipid, phenolic and arachidonic acid (ARA as well as expression of the genes involved in biosynthesis of ARA and lipid were examined in Mortierella alpina CBS 754.68. A significant increase in the arachidonic acid content in lipids that coincided with reduced levels of lipid was obtained. Reduced gene expression occurred presumably due to the steady reduction of carbon and nitrogen resources. However, these energy resources were inefficiently compensated by the breakdown of the accumulated lipids that in turn, induced up-regulated expression of the candidate genes. The results further indicated that the expression of the GLELO encoding gene is a rate-limiting step in the biosynthesis of ARA in the early growth phase.

  6. The importance of SERINE DECARBOXYLASE1 (SDC1) and ethanolamine biosynthesis during embryogenesis of Arabidopsis thaliana.

    Science.gov (United States)

    Yunus, Ian Sofian; Liu, Yu-Chi; Nakamura, Yuki

    2016-11-01

    In plants, ethanolamine is considered a precursor for the synthesis of choline, which is an essential dietary nutrient for animals. An enzyme serine decarboxylase (SDC) has been identified and characterized in Arabidopsis, which directly converts serine to ethanolamine, a precursor to phosphorylethanolamine and its subsequent metabolites in plants. However, the importance of SDC and ethanolamine production in plant growth and development remains unclear. Here, we show that SDC is required for ethanolamine biosynthesis in vivo and essential in plant embryogenesis in Arabidopsis. The knockout of SDC1 caused an embryonic lethal defect due to the developmental arrest of the embryos at the heart stage. During embryo development, the expression was observed at the later stages, at which developmental defect occurred in the knockout mutant. Overexpression of SDC1 in planta increased levels of ethanolamine, phosphatidylethanolamine, and phosphatidylcholine both in leaves and siliques. These results suggest that SDC1 plays an essential role in ethanolamine biosynthesis during the embryogenesis in Arabidopsis.

  7. Composition of Cassia fistula oil and its antifungal activity by disrupting ergosterol biosynthesis.

    Science.gov (United States)

    Irshad, Md; Ahmad, Aijaz; Zafaryab, Md; Ahmad, Farah; Manzoor, Nikhat; Singh, Man; Rizvi, M Moshahid A

    2013-02-01

    Cassia fistula oil was investigated for antifungal activities against standard and clinical isolates of Candida species. Gas chromatography coupled with mass spectrometric (GC-MS) analysis of C. fistula oil revealed the presence of antimicrobial compounds like beta-sitosterol, stigmasterol, ergosterol, betulinic acid, lupeol, fucosterol, alpha-amyrin and friedelin. The minimum inhibitory concentration (MIC) of the pulp and seed oils ranged between 250-300 and 350-500 microg/mL respectively. Both oils also inhibited by > or = 63.8% ergosterol bio-synthesis in Candida cell wall {fluconazole (standard) > or = 89.1%)}. The MICs were significantly correlated with the ergosterol content decrease in the cell wall (Student's t test p Cassia fistula oil that primarily target ergosterol biosynthesis in Candida cell wall.

  8. Alginate Biosynthesis Factories in Pseudomonas fluorescens: Localization and Correlation with Alginate Production Level.

    Science.gov (United States)

    Maleki, Susan; Almaas, Eivind; Zotchev, Sergey; Valla, Svein; Ertesvåg, Helga

    2015-12-11

    Pseudomonas fluorescens is able to produce the medically and industrially important exopolysaccharide alginate. The proteins involved in alginate biosynthesis and secretion form a multiprotein complex spanning the inner and outer membranes. In the present study, we developed a method by which the porin AlgE was detected by immunogold labeling and transmission electron microscopy. Localization of the AlgE protein was found to depend on the presence of other proteins in the multiprotein complex. No correlation was found between the number of alginate factories and the alginate production level, nor were the numbers of these factories affected in an algC mutant that is unable to produce the precursor needed for alginate biosynthesis. Precursor availability and growth phase thus seem to be the main determinants for the alginate production rate in our strain. Clustering analysis demonstrated that the alginate multiprotein complexes were not distributed randomly over the entire outer cell membrane surface.

  9. Extreme promiscuity of a bacterial and a plant diterpene synthase enables combinatorial biosynthesis.

    Science.gov (United States)

    Jia, Meirong; Potter, Kevin C; Peters, Reuben J

    2016-09-01

    Diterpenes are widely distributed across many biological kingdoms, where they serve a diverse range of physiological functions, and some have significant industrial utility. Their biosynthesis involves class I diterpene synthases (DTSs), whose activity can be preceded by that of class II diterpene cyclases (DTCs). Here, a modular metabolic engineering system was used to examine the promiscuity of DTSs. Strikingly, both a bacterial and plant DTS were found to exhibit extreme promiscuity, reacting with all available precursors with orthogonal activity, producing an olefin or hydroxyl group, respectively. Such DTS promiscuity enables combinatorial biosynthesis, with remarkably high yields for these unoptimized non-native enzymatic combinations (up to 15mg/L). Indeed, it was possible to readily characterize the 13 unknown products. Notably, 16 of the observed diterpenes were previously inaccessible, and these results provide biosynthetic routes that are further expected to enable assembly of more extended pathways to produce additionally elaborated 'non-natural' diterpenoids.

  10. Fluorinated natural products: the biosynthesis of fluoroacetate and 4-fluorothreonine in Streptomyces cattleya.

    Science.gov (United States)

    Murphy, Cormac D; Schaffrath, Christoph; O'Hagan, David

    2003-07-01

    Organofluorine compounds are rare in Nature, with only a handful known to be produced by some species of plant and two microorganisms. Consequently, the mechanism of enzymatic carbon-fluorine bond formation is poorly understood. The bacterium Streptomyces cattleya biosynthesises fluoroacetate and 4-fluorothreonine as secondary metabolites and is a convenient system to study the biosynthesis and enzymology of fluorometabolite production. Using stable-isotope labelled precursors it has been shown that there is a common intermediate in the biosynthesis of the fluorometabolites, which has recently been identified as fluoroacetaldehyde. Studies with cell-free extracts of S. cattleya have identified two enzymes, an aldehyde dehydrogenase and a threonine transaldolase, that are involved in the biotransformation of fluoroacetaldehyde to fluoroacetate and 4-fluorothreonine.

  11. A putative gene cluster from a Lyngbya wollei bloom that encodes paralytic shellfish toxin biosynthesis.

    Directory of Open Access Journals (Sweden)

    Troco K Mihali

    Full Text Available Saxitoxin and its analogs cause the paralytic shellfish-poisoning syndrome, adversely affecting human health and coastal shellfish industries worldwide. Here we report the isolation, sequencing, annotation, and predicted pathway of the saxitoxin biosynthetic gene cluster in the cyanobacterium Lyngbya wollei. The gene cluster spans 36 kb and encodes enzymes for the biosynthesis and export of the toxins. The Lyngbya wollei saxitoxin gene cluster differs from previously identified saxitoxin clusters as it contains genes that are unique to this cluster, whereby the carbamoyltransferase is truncated and replaced by an acyltransferase, explaining the unique toxin profile presented by Lyngbya wollei. These findings will enable the creation of toxin probes, for water monitoring purposes, as well as proof-of-concept for the combinatorial biosynthesis of these natural occurring alkaloids for the production of novel, biologically active compounds.

  12. Elucidating steroid alkaloid biosynthesis in Veratrum californicum: production of verazine in Sf9 cells.

    Science.gov (United States)

    Augustin, Megan M; Ruzicka, Dan R; Shukla, Ashutosh K; Augustin, Jörg M; Starks, Courtney M; O'Neil-Johnson, Mark; McKain, Michael R; Evans, Bradley S; Barrett, Matt D; Smithson, Ann; Wong, Gane Ka-Shu; Deyholos, Michael K; Edger, Patrick P; Pires, J Chris; Leebens-Mack, James H; Mann, David A; Kutchan, Toni M

    2015-06-01

    Steroid alkaloids have been shown to elicit a wide range of pharmacological effects that include anticancer and antifungal activities. Understanding the biosynthesis of these molecules is essential to bioengineering for sustainable production. Herein, we investigate the biosynthetic pathway to cyclopamine, a steroid alkaloid that shows promising antineoplastic activities. Supply of cyclopamine is limited, as the current source is solely derived from wild collection of the plant Veratrum californicum. To elucidate the early stages of the pathway to cyclopamine, we interrogated a V. californicum RNA-seq dataset using the cyclopamine accumulation profile as a predefined model for gene expression with the pattern-matching algorithm Haystack. Refactoring candidate genes in Sf9 insect cells led to discovery of four enzymes that catalyze the first six steps in steroid alkaloid biosynthesis to produce verazine, a predicted precursor to cyclopamine. Three of the enzymes are cytochromes P450 while the fourth is a γ-aminobutyrate transaminase; together they produce verazine from cholesterol.

  13. Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

    Science.gov (United States)

    Spencer, Jonathan B; Leadlay, Peter F

    2014-01-01

    Summary Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L−1 dehydroxymonensin; ΔmonE: 0.50 g L−1 demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L−1 dehydroxydemethylmonensin). Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation. PMID:24605157

  14. Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

    Directory of Open Access Journals (Sweden)

    Wolfgang Hüttel

    2014-02-01

    Full Text Available Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L−1 dehydroxymonensin; ΔmonE: 0.50 g L−1 demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L−1 dehydroxydemethylmonensin. Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation.

  15. An Acidic pH is a determinant factor for TRI genes expression and trichothecenes B biosynthesis in Fusarium graminearum

    OpenAIRE

    2010-01-01

    Abstract Reducing production of trichothecene B by Fusarium graminearum on cereals is necessary to avoid contamination leading to yields reduction and having harmful impacts on human and animal health. Understanding how trichothecenes biosynthesis is induced is essential. Effect of ambient pH on fungal growth, toxin biosynthesis and TRI genes expression was studied during in vitro liquid culture of F. graminearum on minimal medium. Fungal development stopped at day 3 after a sharp ...

  16. Effects of Molybdenum on the Intermediates of Chlorophyll Biosynthesis in Winter Wheat Cultivars Under Low Temperature

    Institute of Scientific and Technical Information of China (English)

    YU Min; HU Cheng-xiao; WANG Yun-hua

    2006-01-01

    The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of chlorophyll biosynthesis were analyzed in winter wheat cultivars in soil culture, miniblock culture, and solution culture to study the effects of Mo on chlorophyll biosynthesis without Mo addition (CK, soil available Mo 0.112 mg kg-1) and Mo addition (+ Mo,0.13 mg kg-1 Mo was added). Laevulinic acid (LA), the competitive analog of δ-aminolaevulinic acid (ALA) was also introduced in the experiment. The ratio of Chl a/Chl b was constant between CK and + Mo treatment, whereas it increased at low temperature, which indicated that Mo deficiency did not inhibit the transformation of Chl a to Chl b at low temperature. Under Mo deficiency, the contents of protochlorophyll (Pchl), Mg-protoporphyrin Ⅸ (Mg-Proto Ⅸ),protoporphyrin Ⅸ (proto Ⅸ), and uroporphyrinogen Ⅲ (Uro Ⅲ) decreased [Uro Ⅲ decreased significantly (P < 0.01)],whereas ALA and glutamate increased significantly (P < 0.01) compared with that of Mo addition, which suggested that the transformation from ALA to Ufo Ⅲ might be inhibited. The content of ALA reversed after addition of LA, it was significantly higher (P<0.01) in Mo addition than in CK. The results indicated that the transformation from ALA to Uro Ⅲ was blocked under Mo deficiency, which resulted in the inhibition of the biosynthesis of chlorophyll and led to the decrease of chlorophyll in winter wheat cultivars.

  17. Engineering of photosynthetic mannitol biosynthesis from CO2 in a cyanobacterium

    DEFF Research Database (Denmark)

    Jacobsen, Jacob Hedemand; Frigaard, Niels-Ulrik

    2014-01-01

    d-Mannitol (hereafter denoted mannitol) is used in the medical and food industry and is currently produced commercially by chemical hydrogenation of fructose or by extraction from seaweed. Here, the marine cyanobacterium Synechococcus sp. PCC 7002 was genetically modified to photosynthetically...... concentration of 1.1gmannitolL(-1) and a production rate of 0.15gmannitolL(-1)day(-1). This system may be useful for biosynthesis of valuable sugars and sugar derivatives from CO2 in cyanobacteria....

  18. Current Understanding on Aflatoxin Biosynthesis and Future Perspective in Reducing Aflatoxin Contamination

    OpenAIRE

    2012-01-01

    Traditional molecular techniques have been used in research in discovering the genes and enzymes that are involved in aflatoxin formation and genetic regulation. We cloned most, if not all, of the aflatoxin pathway genes. A consensus gene cluster for aflatoxin biosynthesis was discovered in 2005. The factors that affect aflatoxin formation have been studied. In this report, the author summarized the current status of research progress and future possibilities that may be used for solving afla...

  19. Radiographic features of the skeleton in disorders of post-squalene cholesterol biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Massimiliano; Edery, Patrick [Hospices Civils de Lyon, Genetic Department, Referral Centre for Developmental Abnormalities, Femme-Mere-Enfant Hospital, Bron (France); INSERM U1028 UMR CNRS 5,292, UCBL, CRNL TIGER Team, CH le Vinater, Bron (France); Hall, Christine M. [Retired from Department of Radiology, Great Ormond Street Hospital, London (United Kingdom); Bouvier, Raymonde; Collardeau-Frachon, Sophie [Hospices Civils de Lyon, Department of Pathology, CBPE, Bron (France); Le Breton, Frederique [Hospices Civils de Lyon, Department of Pathology, Croix-Rousse Hospital, Lyon (France); Bucourt, Martine [AP-HP, Foetopathology Unit, Jean Verdier Hospital, Bondy (France); Cordier, Marie Pierre [Hospices Civils de Lyon, Genetic Department, Referral Centre for Developmental Abnormalities, Femme-Mere-Enfant Hospital, Bron (France); Vianey-Saban, Christine [Hospices Civils de Lyon, Department of Inborn Errors of Metabolism and Neonatal Screening, CBPE, Bron (France); Parenti, Giancarlo; Andria, Generoso [Federico II University, Department of Translational Medical Sciences, Section of Pediatrics, Naples (Italy); Le Merrer, Martine [AP-HP, Genetic Department, Referal Centre for Skeletal Dysplasias, Institut Imagine, Necker-Enfants Malades Hospital, Paris (United Kingdom); Offiah, Amaka C. [Stephenson Wing Sheffield Children' s NHS Foundation Trust Western Bank, Radiology Department, Children' s Hospital, Academic Unit of Child Health Room C4, Sheffield (United Kingdom)

    2015-07-15

    Disorders of post-squalene cholesterol biosynthesis are inborn errors of metabolism characterised by multiple congenital abnormalities, including significant skeletal involvement. The most frequent and best-characterised example is the Smith-Lemli-Opitz syndrome. Nine other disorders are known, namely autosomal-recessive Antley-Bixler syndrome, Greenberg dysplasia, X-linked dominant chondrodysplasia punctata, X-linked recessive male emopamil-binding protein deficiency, CHILD syndrome, CK syndrome, sterol C4 methyloxidase-like deficiency, desmosterolosis and lathosterolosis. This study provides an overview of the radiologic features observed in these diseases. A common pattern of limb abnormalities is recognisable, including polydactyly, which is typically post-axial and rarely interdigital and can involve all four limbs, and syndactyly of the toes. Chondrodysplasia punctata is specifically associated with a subgroup of disorders of cholesterol biosynthesis (Greenberg dysplasia, CHILD syndrome, X-linked dominant chondrodysplasia punctata, male emopamil-binding protein deficiency). The possible occurrence of epiphyseal stippling in the Smith-Lemli-Opitz syndrome, initially reported, does not appear to be confirmed. Stippling is also associated with other congenital disorders such as chromosomal abnormalities, brachytelephalangic chondrodysplasia punctata (X-linked recessive chondrodysplasia punctata, disruptions of vitamin K metabolism, maternal autoimmune diseases), rhizomelic chondrodysplasia punctata (peroxisomal disorders) and lysosomal storage disorders. In the differential diagnosis of epiphyseal stippling, a moth-eaten appearance of bones, asymmetry, or presence of a common pattern of limb abnormalities indicate inborn errors of cholesterol biosynthesis. We highlight the specific differentiating radiologic features of disorders of post-squalene cholesterol biosynthesis. (orig.)

  20. Cloning and Characterization of the Polyether Salinomycin Biosynthesis Gene Cluster of Streptomyces albus XM211

    OpenAIRE

    Jiang, Chunyan; Wang, Hougen; Kang, Qianjin; Jing LIU; Bai, Linquan

    2012-01-01

    Salinomycin is widely used in animal husbandry as a food additive due to its antibacterial and anticoccidial activities. However, its biosynthesis had only been studied by feeding experiments with isotope-labeled precursors. A strategy with degenerate primers based on the polyether-specific epoxidase sequences was successfully developed to clone the salinomycin gene cluster. Using this strategy, a putative epoxidase gene, slnC, was cloned from the salinomycin producer Streptomyces albus XM211...

  1. Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus

    OpenAIRE

    Dutter, Brendan F.; Mike, Laura A.; Reid, Paul R.; Chong, Katherine M.; Ramos-Hunter, Susan J.; Skaar, Eric P.; Sulikowski, Gary A.

    2016-01-01

    Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if...

  2. Acetylation serves as a protective group in noscapine biosynthesis in opium poppy.

    Science.gov (United States)

    Dang, Thu-Thuy T; Chen, Xue; Facchini, Peter J

    2015-02-01

    We have characterized four sequential enzymes that transform 1-hydroxy-N-methylcanadine to narcotoline hemiacetal, completing our elucidation of noscapine biosynthesis in opium poppy. Two cytochromes P450 catalyze hydroxylations at C13 and C8 on the protoberberine scaffold, the latter step inducing ring opening and the formation of an aldehyde moiety. Acetylation at C13 before C8 hydroxylation introduces a protective group subsequently hydrolyzed by a carboxylesterase, which triggers rearrangement to a cyclic hemiacetal.

  3. Transcriptome analysis of medicinal plant Salvia miltiorrhiza and identification of genes related to tanshinone biosynthesis.

    Directory of Open Access Journals (Sweden)

    Lei Yang

    Full Text Available Salvia miltiorrhiza Bunge, a perennial plant of Lamiaceae, accumulates abietane-type diterpenoids of tanshinones in root, which have been used as traditional Chinese medicine to treat neuroasthenic insomnia and cardiovascular diseases. However, to date the biosynthetic pathway of tanshinones is only partially elucidated and the mechanism for their root-specific accumulation remains unknown. To identify enzymes and transcriptional regulators involved in the biosynthesis of tanshinones, we conducted transcriptome profiling of S. miltiorrhiza root and leaf tissues using the 454 GS-FLX pyrosequencing platform, which generated 550,546 and 525,292 reads, respectively. RNA sequencing reads were assembled and clustered into 64,139 unigenes (29,883 isotigs and 34,256 singletons. NCBI non-redundant protein databases (NR and Swiss-Prot database searches anchored 32,096 unigenes (50% with functional annotations based on sequence similarities. Further assignments with Gene Ontology (GO terms and KEGG biochemical pathways identified 168 unigenes referring to the terpenoid backbone biosynthesis (including 144 MEP and MVA pathway genes and 24 terpene synthases. Comparative analysis of the transcriptomes identified 2,863 unigenes that were highly expressed in roots, including those encoding enzymes of early steps of tanshinone biosynthetic pathway, such as copalyl diphosphate synthase (SmCPS, kaurene synthase-like (SmKSL and CYP76AH1. Other differentially expressed unigenes predicted to be related to tanshinone biosynthesis fall into cytochrome P450 monooxygenases, dehydrogenases and reductases, as well as regulatory factors. In addition, 21 P450 genes were selectively confirmed by real-time PCR. Thus we have generated a large unigene dataset which provides a valuable resource for further investigation of the radix development and biosynthesis of tanshinones.

  4. Total biosynthesis of opiates by stepwise fermentation using engineered Escherichia coli.

    OpenAIRE

    NAKAGAWA, Akira; Matsumura, Eitaro; Koyanagi, Takashi; Katayama, Takane; Kawano, Noriaki; Yoshimatsu, Kayo; Yamamoto, Kenji; Kumagai, Hidehiko; Sato, Fumihiko; Minami, Hiromichi

    2016-01-01

    Opiates such as morphine and codeine are mainly obtained by extraction from opium poppies. Fermentative opiate production in microbes has also been investigated, and complete biosynthesis of opiates from a simple carbon source has recently been accomplished in yeast. Here we demonstrate that Escherichia coli serves as an efficient, robust and flexible platform for total opiate synthesis. Thebaine, the most important raw material in opioid preparations, is produced by stepwise culture of four ...

  5. Breakdown of the regulatory control of pyrimidine biosynthesis in human breast cancer cells.

    Science.gov (United States)

    Sigoillot, Frederic D; Sigoillot, Severine M; Guy, Hedeel I

    2004-04-20

    The activity of the de novo pyrimidine biosynthetic pathway in the MCF7 breast cancer cells was 4.4-fold higher than that in normal MCF10A breast cells. Moreover, while pyrimidine biosynthesis in MCF10A was tightly regulated, increasing as the culture matured and subsequently down-regulated in confluency, the biosynthetic rate in MCF7 cells remained elevated and invariant in all growth phases. The flux through the pathway is regulated by carbamoyl phosphate synthetase, a component of the multifunctional protein, CAD. The intracellular CAD concentration was 3.5- to 4-fold higher in MCF7 cells, an observation that explains the high rate of pyrimidine biosynthesis but cannot account for the lack of growth-dependent regulation. In MCF10A cells, up-regulation of the pathway in the exponential growth phase resulted from MAP kinase phosphorylation of CAD Thr456. The pathway was subsequently down-regulated by dephosphorylation of P approximately Thr456 and the phosphorylation of CAD by PKA. In contrast, the CAD P approximately Thr456 was persistently phosphorylated in MCF7 cells, while the PKA site remained unphosphorylated and consequently the activity of the pathway was elevated in all growth phases. In support of this interpretation, inhibition of MAP kinase in MCF7 cells decreased CAD P approximately Thr456, increased PKA phosphorylation and decreased pyrimidine biosynthesis. Conversely, transfection of MCF10A with constructs that elevated MAP kinase activity increased CAD P approximately Thr456 and the pyrimidine biosynthetic rate. The differences in the CAD phosphorylation state responsible for unregulated pyrimidine biosynthesis in MCF7 cells are likely to be a consequence of the elevated MAP kinase activity and the antagonism between MAP kinase- and PKA-mediated phosphorylations.

  6. Biosynthesis of endocannabinoids and their modes of action in neurodegenerative diseases

    DEFF Research Database (Denmark)

    van der Stelt, M.; Veldink, G.A.; Vliegenthart, J.F.G.

    2003-01-01

    Endocannabinoids are thought to function as retrograde messengers, which modulate neurotransmitter release by activating presynaptic cannabinoid receptors. Anandamide and 2-arachidonoylglycerol (2-AG) are the two best studied endogenous lipids which can act as endocannabinoids. Together...... with the proteins responsible for their biosynthesis, inactivation and the cannabinoid receptors, these lipids constitute the endocannabinoid system. This system is proposed to be involved in various neurodegenerative diseases such as Parkinson's and Huntington's diseases as well as Multiple Sclerosis. It has been...

  7. Identification of a Catalase-Phenol Oxidase in Betalain Biosynthesis in Red Amaranth (Amaranthus cruentus)

    OpenAIRE

    Teng, Xiao-Lu; Chen, Ning; Xiao, Xing-Guo

    2016-01-01

    Betalains are a group of nitrogen-containing pigments that color plants in most families of Caryophyllales. Their biosynthesis has long been proposed to begin with hydroxylation of L-tyrosine to L-DOPA through monophenolase activity of tyrosinase, but biochemical evidence in vivo remains lacking. Here we report that a Group 4 catalase, catalase-phenol oxidase (named as AcCATPO), was identified, purified and characterized from leaves of Amaranthus cruentus, a betalain plant. The purified enzym...

  8. Identification of a catalase-phenol oxidase in betalain biosynthesis in red amaranth (Amaranthus cruentus)

    OpenAIRE

    Xiao-Lu eTeng; Ning eChen; Xing-Guo eXiao

    2016-01-01

    Betalains are a group of nitrogen-containing pigments that color plants in most families of Caryophyllales. Their biosynthesis has long been proposed to begin with hydroxylation of L-tyrosine to L-DOPA through monophenolase activity of tyrosinase, but biochemical evidence in vivo remains lacking. Here we report that a Group 4 catalase, catalase-phenol oxidase (named as AcCATPO), was identified, purified and characterized from leaves of Amaranthus cruentus, a betalain plant. The purified enzym...

  9. Biosynthesis of membrane cholesterol during peripheral nerve development, degeneration and regeneration.

    Science.gov (United States)

    Yao, J K

    1988-09-01

    Biosynthesis of peripheral nerve cholesterol was investigated by the in vivo and in vitro incorporation of [1-14C]-acetate into sciatic endoneurium of normal rats during development, degeneration and regeneration. Labeled sterols were rapidly formed (less than 10 min) within the endoneurial portion of sciatic nerve after [1-14C]acetate administration by intraneural injection. The majority of labeled sterols were initially found in lanosterol and desmosterol. After six hr, the 14C-labeling in both precursors was decreased to minimum, whereas cholesterol became the major labeled product of sterol. As myelination proceeded, the incorporation of [1-14C]acetate into endoneurial cholesterol decreased rapidly and reached a minimum after six mo. In mature adult nerve, an increased proportion of biosynthesis of lanosterol and desmosterol also was demonstrated. The in vitro incorporation of [1-14C]acetate into cholesterol was inhibited during Wallerian degeneration. Instead, cholesteryl esters were labeled as the major sterol product. Such inhibition, however, was not observed in the adult Trembler nerve (Brain Res. 325, 21-27, 1985), which is presumed to be due to a primary metabolic disorder of Schwann cells. The cholesterol biosynthesis was gradually resumed in degenerated nerve by either regeneration of crush-injured nerve or reattachment of the transected nerve. These results suggest that cholesterol biosynthesis in peripheral nerve relies on the axon to provide necessary substrates. De novo synthesis appears to be one of the major sources of endoneurial cholesterol that forms and maintains peripheral nerve myelin.

  10. HSF-1 is involved in regulation of ascaroside pheromone biosynthesis by heat stress in Caenorhabditis elegans.

    Science.gov (United States)

    Joo, Hyoe-Jin; Park, Saeram; Kim, Kwang-Youl; Kim, Mun-Young; Kim, Heekyeong; Park, Donha; Paik, Young-Ki

    2016-03-15

    The nematode worm Caenorhabditis elegans survives by adapting to environmental stresses such as temperature extremes by increasing the concentrations of ascaroside pheromones, termed ascarosides or daumones, which signal early C. elegans larvae to enter a non-aging dauer state for long-term survival. It is well known that production of ascarosides is stimulated by heat stress, resulting in enhanced dauer formation by which worms can adapt to environmental insults. However, the molecular mechanism by which ascaroside pheromone biosynthesis is stimulated by heat stress remains largely unknown. In the present study, we show that the heat-shock transcription factor HSF-1 can mediate enhanced ascaroside pheromone biosynthesis in response to heat stress by activating the peroxisomal fatty acid β-oxidation genes in C. elegans. To explore the potential molecular mechanisms, we examined the four major genes involved in the ascaroside biosynthesis pathway and then quantified the changes in both the expression of these genes and ascaroside production under heat-stress conditions. The transcriptional activation of ascaroside pheromone biosynthesis genes by HSF-1 was quite notable, which is not only supported by chromatin immunoprecipitation assays, but also accompanied by the enhanced production of chemically detectable major ascarosides (e.g. daumones 1 and 3). Consequently, the dauer formation rate was significantly increased by the ascaroside pheromone extracts from N2 wild-type but not from hsf-1(sy441) mutant animals grown under heat-stress conditions. Hence heat-stress-enhanced ascaroside production appears to be mediated at least in part by HSF-1, which seems to be important in adaptation strategies for coping with heat stress in this nematode.

  11. Chemical defense balanced by sequestration and de novo biosynthesis in a lepidopteran specialist.

    Directory of Open Access Journals (Sweden)

    Joel Fürstenberg-Hägg

    Full Text Available The evolution of sequestration (uptake and accumulation relative to de novo biosynthesis of chemical defense compounds is poorly understood, as is the interplay between these two strategies. The Burnet moth Zygaena filipendulae (Lepidoptera and its food-plant Lotus corniculatus (Fabaceae poses an exemplary case study of these questions, as Z. filipendulae belongs to the only insect family known to both de novo biosynthesize and sequester the same defense compounds directly from its food-plant. Z. filipendulae and L. corniculatus both contain the two cyanogenic glucosides linamarin and lotaustralin, which are defense compounds that can be hydrolyzed to liberate toxic hydrogen cyanide. The overall amounts and ratios of linamarin and lotaustralin in Z. filipendulae are tightly regulated, and only to a low extent reflect the ratio in the ingested food-plant. We demonstrate that Z. filipendulae adjusts the de novo biosynthesis of CNglcs by regulation at both the transcriptional and protein level depending on food plant composition. Ultimately this ensures that the larva saves energy and nitrogen while maintaining an effective defense system to fend off predators. By using in situ PCR and immunolocalization, the biosynthetic pathway was resolved to the larval fat body and integument, which infers rapid replenishment of defense compounds following an encounter with a predator. Our study supports the hypothesis that de novo biosynthesis of CNglcs in Z. filipendulae preceded the ability to sequester, and facilitated a food-plant switch to cyanogenic plants, after which sequestration could evolve. Preservation of de novo biosynthesis allows fine-tuning of the amount and composition of CNglcs in Z. filipendulae.

  12. Evolutionary Aspects and Regulation of Tetrapyrrole Biosynthesis in Cyanobacteria under Aerobic and Anaerobic Environments

    Directory of Open Access Journals (Sweden)

    Yuichi Fujita

    2015-03-01

    Full Text Available Chlorophyll a (Chl is a light-absorbing tetrapyrrole pigment that is essential for photosynthesis. The molecule is produced from glutamate via a complex biosynthetic pathway comprised of at least 15 enzymatic steps. The first half of the Chl pathway is shared with heme biosynthesis, and the latter half, called the Mg-branch, is specific to Mg-containing Chl a. Bilin pigments, such as phycocyanobilin, are additionally produced from heme, so these light-harvesting pigments also share many common biosynthetic steps with Chl biosynthesis. Some of these common steps in the biosynthetic pathways of heme, Chl and bilins require molecular oxygen for catalysis, such as oxygen-dependent coproporphyrinogen III oxidase. Cyanobacteria thrive in diverse environments in terms of oxygen levels. To cope with Chl deficiency caused by low-oxygen conditions, cyanobacteria have developed elaborate mechanisms to maintain Chl production, even under microoxic environments. The use of enzymes specialized for low-oxygen conditions, such as oxygen-independent coproporphyrinogen III oxidase, constitutes part of a mechanism adapted to low-oxygen conditions. Another mechanism adaptive to hypoxic conditions is mediated by the transcriptional regulator ChlR that senses low oxygen and subsequently activates the transcription of genes encoding enzymes that work under low-oxygen tension. In diazotrophic cyanobacteria, this multilayered regulation also contributes in Chl biosynthesis by supporting energy production for nitrogen fixation that also requires low-oxygen conditions. We will also discuss the evolutionary implications of cyanobacterial tetrapyrrole biosynthesis and regulation, because low oxygen-type enzymes also appear to be evolutionarily older than oxygen-dependent enzymes.

  13. Comparative Transcriptome Analysis Reveals Effects of Exogenous Hematin on Anthocyanin Biosynthesis during Strawberry Fruit Ripening

    OpenAIRE

    2016-01-01

    Anthocyanin in strawberries has a positive effect on fruit coloration. In this study, the role of exogenous hematin on anthocyanin biosynthesis was investigated. Our result showed that the white stage of strawberries treated with exogenous hematin had higher anthocyanin content, compared to the control group. Among all treatments, 5 μM of hematin was the optimal condition to promote color development. In order to explore the molecular mechanism of fruit coloring regulated by hematin, transcri...

  14. AmcA - a putative mitochondrial ornithine transporter supporting fungal siderophore biosynthesis

    Directory of Open Access Journals (Sweden)

    Lukas eSchafferer

    2015-04-01

    Full Text Available Iron is an essential nutrient required for a wide range of cellular processes. The opportunistic fungal pathogen Aspergillus fumigatus employs low-molecular mass iron-specific chelators, termed siderophores, for uptake, storage and intracellular iron distribution, which play a crucial role in the pathogenicity of this fungus. Siderophore biosynthesis depends on coordination with the supply of its precursor ornithine, produced mitochondrially from glutamate or cytosolically via hydrolysis of arginine. In this study, we demonstrate a role of the putative mitochondrial transporter AmcA (AFUA_8G02760 in siderophore biosynthesis of A. fumigatus.Consistent with a role in cellular ornithine handling, AmcA-deficiency resulted in decreased cellular ornithine and arginine contents as well as decreased siderophore production on medium containing glutamine as the sole nitrogen source. In support, arginine and ornithine as nitrogen sources did not impact siderophore biosynthesis due to cytosolic ornithine availability. As revealed by Northern blot analysis, transcript levels of siderophore biosynthetic genes were unresponsive to the cellular ornithine level. In contrast to siderophore production, AmcA deficiency did only mildly decrease the cellular polyamine content, demonstrating cellular prioritization of ornithine use. Nevertheless, AmcA-deficiency increased the susceptibility of A. fumigatus to the polyamine biosynthesis inhibitor eflornithine, most likely due to the decreased ornithine pool. AmcA-deficiency decreased the growth rate particularly on ornithine as the sole nitrogen source during iron starvation and sufficiency, indicating an additional role in the metabolism and fitness of A. fumigatus, possibly in mitochondrial ornithine import. In the Galleria mellonella infection model, AmcA-deficiency did not affect virulence of A. fumigatus, most likely due to the residual siderophore production and arginine availability in this host niche.

  15. Functional Characterization of 4′OMT and 7OMT Genes in BIA Biosynthesis

    OpenAIRE

    Gurkok, Tugba; Ozhuner, Esma; Parmaksiz, Iskender; Özcan, Sebahattin; Turktas, Mine; İPEK, Arif; Demirtas, Ibrahim; Okay, Sezer; Unver, Turgay

    2016-01-01

    Alkaloids are diverse group of secondary metabolites generally found in plants. Opium poppy (Papaver somniferum L.), the only commercial source of morphinan alkaloids, has been used as a medicinal plant since ancient times. It produces benzylisoquinoline alkaloids (BIA) including the narcotic analgesic morphine, the muscle relaxant papaverine, and the anti-cancer agent noscapine. Though BIAs play crucial roles in many biological mechanisms their steps in biosynthesis and the responsible genes...

  16. Functional Characterization of 4´OMT and 7OMT Genes in BIA Biosynthesis

    OpenAIRE

    Tugba eGurkok; Esma eOzhuner; Iskender eParmaksiz; Sebahattin eÖzcan; Mine eTurktas; Arif eIpek; Sezer eOkay; Turgay eUNVER

    2016-01-01

    Alkaloids are diverse group of secondary metabolites generally found in plants. Opium poppy (Papaver somniferum L.), the only commercial source of morphinan alkaloids, has been used as a medicinal plant since ancient times. It produces benzylisoquinoline alkaloids (BIA) including the narcotic analgesic morphine, the muscle relaxant papaverine, and the anti-cancer agent noscapine. Though BIAs play crucial roles in many biological mechanisms their steps in biosynthesis and the responsible genes...

  17. "Glucose and ethanol-dependent transcriptional regulation of the astaxanthin biosynthesis pathway in Xanthophyllomyces dendrorhous"

    OpenAIRE

    Cifuentes Víctor; Baeza Marcelo; Alcaíno Jennifer; Lozano Carla; Wozniak Aniela; Niklitschek Mauricio; Marcoleta Andrés

    2011-01-01

    Abstract Background The yeast Xanthophyllomyces dendrorhous is one of the most promising and economically attractive natural sources of astaxanthin. The biosynthesis of this valuable carotenoid is a complex process for which the regulatory mechanisms remain mostly unknown. Several studies have shown a strong correlation between the carbon source present in the medium and the amount of pigments synthesized. Carotenoid production is especially low when high glucose concentrations are used in th...

  18. MRE: a web tool to suggest foreign enzymes for the biosynthesis pathway design with competing endogenous reactions in mind

    KAUST Repository

    Kuwahara, Hiroyuki

    2016-04-29

    To rationally design a productive heterologous biosynthesis system, it is essential to consider the suitability of foreign reactions for the specific endogenous metabolic infrastructure of a host. We developed a novel web server, called MRE, which, for a given pair of starting and desired compounds in a given chassis organism, ranks biosynthesis routes from the perspective of the integration of new reactions into the endogenous metabolic system. For each promising heterologous biosynthesis pathway, MRE suggests actual enzymes for foreign metabolic reactions and generates information on competing endogenous reactions for the consumption of metabolites. These unique, chassis-centered features distinguish MRE from existing pathway design tools and allow synthetic biologists to evaluate the design of their biosynthesis systems from a different angle. By using biosynthesis of a range of high-value natural products as a case study, we show that MRE is an effective tool to guide the design and optimization of heterologous biosynthesis pathways. The URL of MRE is http://www.cbrc.kaust.edu.sa/mre/.

  19. MRE: a web tool to suggest foreign enzymes for the biosynthesis pathway design with competing endogenous reactions in mind.

    Science.gov (United States)

    Kuwahara, Hiroyuki; Alazmi, Meshari; Cui, Xuefeng; Gao, Xin

    2016-07-08

    To rationally design a productive heterologous biosynthesis system, it is essential to consider the suitability of foreign reactions for the specific endogenous metabolic infrastructure of a host. We developed a novel web server, called MRE, which, for a given pair of starting and desired compounds in a given chassis organism, ranks biosynthesis routes from the perspective of the integration of new reactions into the endogenous metabolic system. For each promising heterologous biosynthesis pathway, MRE suggests actual enzymes for foreign metabolic reactions and generates information on competing endogenous reactions for the consumption of metabolites. These unique, chassis-centered features distinguish MRE from existing pathway design tools and allow synthetic biologists to evaluate the design of their biosynthesis systems from a different angle. By using biosynthesis of a range of high-value natural products as a case study, we show that MRE is an effective tool to guide the design and optimization of heterologous biosynthesis pathways. The URL of MRE is http://www.cbrc.kaust.edu.sa/mre/.

  20. Transcriptome Analysis of Manganese-deficient Chlamydomonas reinhardtii Provides Insight on the Chlorophyll Biosynthesis Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lockhart, Ainsley; Zvenigorodsky, Natasha; Pedraza, Mary Ann; Lindquist, Erika

    2011-08-11

    The biosynthesis of chlorophyll and other tetrapyrroles is a vital but poorly understood process. Recent genomic advances with the unicellular green algae Chlamydomonas reinhardtii have created opportunity to more closely examine the mechanisms of the chlorophyll biosynthesis pathway via transcriptome analysis. Manganese is a nutrient of interest for complex reactions because of its multiple stable oxidation states and role in molecular oxygen coordination. C. reinhardtii was cultured in Manganese-deplete Tris-acetate-phosphate (TAP) media for 24 hours and used to create cDNA libraries for sequencing using Illumina TruSeq technology. Transcriptome analysis provided intriguing insight on possible regulatory mechanisms in the pathway. Evidence supports similarities of GTR (Glutamyl-tRNA synthase) to its Chlorella vulgaris homolog in terms of Mn requirements. Data was also suggestive of Mn-related compensatory up-regulation for pathway proteins CHLH1 (Manganese Chelatase), GUN4 (Magnesium chelatase activating protein), and POR1 (Light-dependent protochlorophyllide reductase). Intriguingly, data suggests possible reciprocal expression of oxygen dependent CPX1 (coproporphyrinogen III oxidase) and oxygen independent CPX2. Further analysis using RT-PCR could provide compelling evidence for several novel regulatory mechanisms in the chlorophyll biosynthesis pathway.

  1. Agrobacterium rhizogenes: Transformed root cultures for the study of polyacetylene metabolism and biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, Y.Y.

    1988-02-01

    Biologically active polyacetylenes are produced at low levels by the roots of members of the Coreopsidinae subtribe in the Asteraceae. Ten taxa of Coreopsis and Bidens were tranformed with Agrobacterium rhizogenes Strain A/sub 4/ and hairy root cultures established. These cultures grew rapidly and produced the same arrays of polyacetylenes as intact roots. The use of transformed roots for the study of polyacetylene biosynthesis is described in this paper. The engineering of plants with resistance to herbicides is now a practical reality because there are economic, intellectual and environmental incentives for using recombinant DNA technology in crop improvement programs, and because the biochemical and genetic basis for herbicide resistance is a simple trait conferred by a single gene. The transformation of plants with genes conferring resistance to insects or disease is more daunting, however, as biologically active secondary metabolites such as some alkaloids are typically products of multienzyme reactions. Photoactive polyacetylenes are probably plant defense chemicals and they are derived by a sequence of desaturation steps from oleic acid, which occurs ubiquitously in higher plants. Although the acetylene pathway may encompass as many genetic messages as those for morphine biosynthesis, it is likley that the genes controlling the biosynthesis of polyacetylenes may be isolated, identified in the near future and transferred via Agrobacterium to economically important plants susceptible to pathogen attack. 58 refs., 4 figs., 3 tabs.

  2. A focus on the biosynthesis and composition of cuticle in fruits.

    Science.gov (United States)

    Lara, Isabel; Belge, Burcu; Goulao, Luis F

    2015-04-29

    Cuticles are plant structures, composed mostly by lipidic layers, synthesized by nonwoody aerial plant organs and deposited on the surface of outer epidermal cell walls. Although its significance has been often disregarded, cuticle deposition modifies organ chemistry, influences mechanical properties, and plays a central role in sensing and interacting with the surrounding environment. Even though some research has been undertaken addressing cuticle biosynthesis and composition in vegetative plant tissues, comparatively less information is available regarding cuticle composition in the epidermis of fruits. However, recent work points to a role for cuticles in the modulation of fruit quality and postharvest performance, indicating that current models for the investigation of fruit development, metabolism, and quality need to integrate a comprehensive knowledge of the cuticle layer. This paper provides an overview of recent findings and observations regarding cuticle biosynthesis and composition in fruits from species of agronomic and economic relevance. Important, but often neglected differences in cuticle composition and biosynthesis patterns among diverse fruit species are described herein to generate an atlas of what is currently known about fruit cuticles and to highlight what remains to be explored. Emphasis is placed on the need to investigate each genetic background considering its own specificities, to permit correlations with the particular physiology of each species considered. Both specific composition and changes during maturation and ripening are reviewed.

  3. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Aymerick Eudes

    Full Text Available Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT, which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5 and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases.

  4. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae

    Science.gov (United States)

    Eudes, Aymerick; Teixeira Benites, Veronica; Wang, George; Baidoo, Edward E. K.; Lee, Taek Soon; Keasling, Jay D.; Loqué, Dominique

    2015-01-01

    Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT), which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae) for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5) and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases. PMID:26430899

  5. Precursor-Directed Combinatorial Biosynthesis of Cinnamoyl, Dihydrocinnamoyl, and Benzoyl Anthranilates in Saccharomyces cerevisiae.

    Science.gov (United States)

    Eudes, Aymerick; Teixeira Benites, Veronica; Wang, George; Baidoo, Edward E K; Lee, Taek Soon; Keasling, Jay D; Loqué, Dominique

    2015-01-01

    Biological synthesis of pharmaceuticals and biochemicals offers an environmentally friendly alternative to conventional chemical synthesis. These alternative methods require the design of metabolic pathways and the identification of enzymes exhibiting adequate activities. Cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates are natural metabolites which possess beneficial activities for human health, and the search is expanding for novel derivatives that might have enhanced biological activity. For example, biosynthesis in Dianthus caryophyllus is catalyzed by hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/ benzoyltransferase (HCBT), which couples hydroxycinnamoyl-CoAs and benzoyl-CoAs to anthranilate. We recently demonstrated the potential of using yeast (Saccharomyces cerevisiae) for the biological production of a few cinnamoyl anthranilates by heterologous co-expression of 4-coumaroyl:CoA ligase from Arabidopsis thaliana (4CL5) and HCBT. Here we report that, by exploiting the substrate flexibility of both 4CL5 and HCBT, we achieved rapid biosynthesis of more than 160 cinnamoyl, dihydrocinnamoyl, and benzoyl anthranilates in yeast upon feeding with both natural and non-natural cinnamates, dihydrocinnamates, benzoates, and anthranilates. Our results demonstrate the use of enzyme promiscuity in biological synthesis to achieve high chemical diversity within a defined class of molecules. This work also points to the potential for the combinatorial biosynthesis of diverse and valuable cinnamoylated, dihydrocinnamoylated, and benzoylated products by using the versatile biological enzyme 4CL5 along with characterized cinnamoyl-CoA- and benzoyl-CoA-utilizing transferases.

  6. Regulation of Ergothioneine Biosynthesis and Its Effect on Mycobacterium tuberculosis Growth and Infectivity.

    Science.gov (United States)

    Richard-Greenblatt, Melissa; Bach, Horacio; Adamson, John; Peña-Diaz, Sandra; Li, Wu; Steyn, Adrie J C; Av-Gay, Yossef

    2015-09-18

    Ergothioneine (EGT) is synthesized in mycobacteria, but limited knowledge exists regarding its synthesis, physiological role, and regulation. We have identified Rv3701c from Mycobacterium tuberculosis to encode for EgtD, a required histidine methyltransferase that catalyzes first biosynthesis step in EGT biosynthesis. EgtD was found to be phosphorylated by the serine/threonine protein kinase PknD. PknD phosphorylates EgtD both in vitro and in a cell-based system on Thr(213). The phosphomimetic (T213E) but not the phosphoablative (T213A) mutant of EgtD failed to restore EGT synthesis in a ΔegtD mutant. The findings together with observed elevated levels of EGT in a pknD transposon mutant during in vitro growth suggests that EgtD phosphorylation by PknD negatively regulates EGT biosynthesis. We further showed that EGT is required in a nutrient-starved model of persistence and is needed for long term infection of murine macrophages.

  7. Microaerobic steroid biosynthesis and the molecular fossil record of Archean life

    Science.gov (United States)

    Waldbauer, Jacob R.; Newman, Dianne K.; Summons, Roger E.

    2011-01-01

    The power of molecular oxygen to drive many crucial biogeochemical processes, from cellular respiration to rock weathering, makes reconstructing the history of its production and accumulation a first-order question for understanding Earth’s evolution. Among the various geochemical proxies for the presence of O2 in the environment, molecular fossils offer a unique record of O2 where it was first produced and consumed by biology: in sunlit aquatic habitats. As steroid biosynthesis requires molecular oxygen, fossil steranes have been used to draw inferences about aerobiosis in the early Precambrian. However, better quantitative constraints on the O2 requirement of this biochemistry would clarify the implications of these molecular fossils for environmental conditions at the time of their production. Here we demonstrate that steroid biosynthesis is a microaerobic process, enabled by dissolved O2 concentrations in the nanomolar range. We present evidence that microaerobic marine environments (where steroid biosynthesis was possible) could have been widespread and persistent for long periods of time prior to the earliest geologic and isotopic evidence for atmospheric O2. In the late Archean, molecular oxygen likely cycled as a biogenic trace gas, much as compounds such as dimethylsulfide do today. PMID:21825157

  8. Organization of chlorophyll biosynthesis and insertion of chlorophyll into the chlorophyll-binding proteins in chloroplasts.

    Science.gov (United States)

    Wang, Peng; Grimm, Bernhard

    2015-12-01

    Oxygenic photosynthesis requires chlorophyll (Chl) for the absorption of light energy, and charge separation in the reaction center of photosystem I and II, to feed electrons into the photosynthetic electron transfer chain. Chl is bound to different Chl-binding proteins assembled in the core complexes of the two photosystems and their peripheral light-harvesting antenna complexes. The structure of the photosynthetic protein complexes has been elucidated, but mechanisms of their biogenesis are in most instances unknown. These processes involve not only the assembly of interacting proteins, but also the functional integration of pigments and other cofactors. As a precondition for the association of Chl with the Chl-binding proteins in both photosystems, the synthesis of the apoproteins is synchronized with Chl biosynthesis. This review aims to summarize the present knowledge on the posttranslational organization of Chl biosynthesis and current attempts to envision the proceedings of the successive synthesis and integration of Chl into Chl-binding proteins in the thylakoid membrane. Potential auxiliary factors, contributing to the control and organization of Chl biosynthesis and the association of Chl with the Chl-binding proteins during their integration into photosynthetic complexes, are discussed in this review.

  9. Modulation of endogenous indole-3-acetic acid biosynthesis in bacteroids within Medicago sativa nodules.

    Science.gov (United States)

    Bianco, C; Senatore, B; Arbucci, S; Pieraccini, G; Defez, R

    2014-07-01

    To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth.

  10. Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus.

    Science.gov (United States)

    Dutter, Brendan F; Mike, Laura A; Reid, Paul R; Chong, Katherine M; Ramos-Hunter, Susan J; Skaar, Eric P; Sulikowski, Gary A

    2016-05-20

    Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if these activities are linked and establish what features of the molecule are required for activity, we synthesized a library of analogs around the structure of 1 and screened them for activation of heme biosynthesis and anaerobic toxicity to investigate structure-activity relationships. The results of this analysis suggest that these activities are not linked. Furthermore, we have identified the structural features that promote each activity and have established two classes of molecules: activators of heme biosynthesis and inhibitors of anaerobic growth. These molecules will serve as useful probes for their respective activities without concern for the off target effects of the parent compound.

  11. The effect of polyamine biosynthesis inhibition on growth and differentiation of the phytopathogenic fungus Sclerotinia sclerotiorum.

    Science.gov (United States)

    Pieckenstain, F L; Gárriz, A; Chornomaz, E M; Sánchez, D H; Ruiz, O A

    2001-12-01

    We studied the effects of several polyamine biosynthesis inhibitors on growth, differentiation, free polyamine levels and in vivo and in vitro activity of polyamine biosynthesis enzymes in Sclerotinia sclerotiorum. Alpha-Difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA) were potent inhibitors of mycelial growth. The effect of DFMO was due to inhibition of ornithine decarboxylase (ODC). No evidence for the existence of an arginine decarboxylase (ADC) pathway was found. The effect of DFMA was partly due to inhibition of ODC, presumably after its conversion into DFMO by mycelial arginase, as suggested by the high activity of this enzyme detected both in intact mycelium and mycelial extracts. In addition, toxic effects of DFMA on cellular processes other than polyamine metabolism might have occurred. Cyclohexylamine (CHA) slightly inhibited mycelial growth and caused an important decrease of free spermidine associated with a drastic increase of free putrescine concentration. Methylglyoxal bis-[guanyl hydrazone] (MGBG) had no effect on mycelial growth. Excepting MGBG, all the inhibitors strongly decreased sclerotial formation. Results demonstrate that sclerotial development is much more sensitive to polyamine biosynthesis inhibition than mycelial growth. Our results suggest that mycelial growth can be supported either by spermidine or putrescine, while spermidine (or the putrescine/spermidine ratio) is important for sclerotial formation to occur. Ascospore germination was completely insensitive to the inhibitors.

  12. Roles of Biomolecules in the Biosynthesis of Silver Nanoparticles:Case of Gardenia jasminoides Extract

    Institute of Scientific and Technical Information of China (English)

    吕芬芬; 高艺; 黄加乐; 孙道华; 李清彪

    2014-01-01

    Rapid development of biosynthesis of metal nanoparticles using plants has attracted extensive interests to further investigate this novel and eco-friendly method. In the biosynthesis process, the plant may act as reducing agent, capping agent or shape directing agent. However, identifying specific roles of various components in the plant is challenging. In this study, we use biosynthesis of silver nanoparticles with Gardenia jasminoides Ellis ex-tract to address this issue. The formation process of silver nanoparticles is investigated and the nanoparticles are characterized with the ultraviolet-visible spectroscopy, Fourier transform infrared spectra and scanning electron mi-croscopy. The results indicate that the Gardenia jasminoides Ellis extract can reduce silver ions to form silver nanoparticles, stabilize the nanoparticles, and affect the growth of silver nanocrystal to form silver nanowires. Only geniposide in the extract exhibits good shape-directing ability for silver nanowires. It is found that bovine albumin is a potential capping agent, whereas rutin, gallic acid and chlorogenic acid possess reducing and capping ability.

  13. Resveratrol stimulates cortisol biosynthesis by activating SIRT-dependent deacetylation of P450scc.

    Science.gov (United States)

    Li, Donghui; Dammer, Eric B; Sewer, Marion B

    2012-07-01

    In the human adrenal cortex, cortisol is synthesized from cholesterol by members of the cytochrome P450 superfamily and hydroxysteroid dehydrogenases. Both the first and last steps of cortisol biosynthesis occur in mitochondria. Based on our previous findings that activation of ACTH signaling changes the ratio of nicotinamide adenine dinucleotide (NAD) phosphate to reduced NAD phosphate in adrenocortical cells, we hypothesized that pyridine nucleotide metabolism may regulate the activity of the mitochondrial NAD(+)-dependent sirtuin (SIRT) deacetylases. We show that resveratrol increases the protein expression and half-life of P450 side chain cleavage enzyme (P450scc). The effects of resveratrol on P450scc protein levels and acetylation status are dependent on SIRT3 and SIRT5 expression. Stable overexpression of SIRT3 abrogates the cellular content of acetylated P450scc, concomitant with an increase in P450scc protein expression and cortisol secretion. Mutation of K148 and K149 to alanine stabilizes the expression of P450scc and results in a 1.5-fold increase in pregnenolone biosynthesis. Finally, resveratrol also increases the protein expression of P450 11β, another mitochondrial enzyme required for cortisol biosynthesis. Collectively, this study identifies a role for NAD(+)-dependent SIRT deacetylase activity in regulating the expression of mitochondrial steroidogenic P450.

  14. Fungus-mediated synthesis of gold nanoparticles and standardization of parameters for its biosynthesis.

    Science.gov (United States)

    Tidke, Pritish R; Gupta, Indarchand; Gade, Aniket K; Rai, Mahendra

    2014-12-01

    We report the extracellular biosynthesis of gold nanoparticles (AuNPs) using a fungus Fusarium acuminatum. Mycosynthesis of Au-NPs was carried out by challenging the fungal cells filtrate with HAuCl 4 solution (1 mM), as nanoparticles synthesizing enzyme secrete extracellularly by the fungi. The AuNPs were characterized with the help of UV-Visible spectrophotometer, Fourier Transform Infrared spectroscopy, Zeta Potential, X-ray diffraction (XRD) and Transmission electron microscopy (TEM). We observed absorbance peak in between 520 nm-550 nm corresponding to the surface plasmon absorbance of the gold nanoparticles. The nanoparticles synthesized in the present investigation were found to be capped by proteins. XRD results showed that the distinctive formation of crystalline gold nanoparticles in the solution. The spherical and polydispersed AuNPs in the range 8 to 28 nm with average size of 17 nm were observed by TEM analysis. We also standardized the parameters like the effect of pH, temperature and salt concentration on the biosynthesis of gold nanoparticles. It was found that acidic pH, 1 mM salt concentration and 37 (°)C temperature were found to be optimum for the synthesis of Au-NPs. Therefore, the present study introduces the easy, better and cheaper method for biosynthesis of AuNPs.

  15. Stimulant effect of nitric oxide generator and roxatidine on mucin biosynthesis of rat gastric oxyntic mucosa.

    Science.gov (United States)

    Ichikawa, T; Ishihara, K; Kusakabe, T; Kawakami, T; Hotta, K

    1999-01-01

    Although the involvement of nitric oxide (NO) in an increasing gastric mucus metabolism has been reported, information on whether or not its activation is limited to the specific mucus-producing cells is lacking. In this paper, we report the effect of the exogenous NO-donor, isosorbide dinitrate (ISDN), and second-generation histamine H2 receptor antagonist roxatidine (2-acetoxy-N-(3-[m-(1-piperidinylmethyl)phenoxy]propyl)acetamide hydrochloride) which is demonstrated to accelerate the mucin metabolism mediated by endogenous NO, on the mucin biosynthesis in distinct sites and layers of the rat gastric mucosa using an organ culture technique. Radiolabeled mucin was obtained from the tissue of full-thickness and the deep corpus layer, and the antrum of the rat stomach incubated for 5 hr with [3H]glucosamine(GlcN) in vitro. With the addition of ISDN to the culture medium, 3H-labeled mucin in the full-thickness corpus mucosa increased to 124-145% of the control (proxatidine stimulated the mucin biosynthesis in the full-thickness corpus mucosa, but not in the gland mucous cell layer. These results suggest that the stimulation of the mucin biosynthesis mediated by NO is restricted to the surface mucous cells of the rat gastric oxyntic mucosa.

  16. Inhibition of pyrimidine biosynthesis pathway suppresses viral growth through innate immunity.

    Directory of Open Access Journals (Sweden)

    Marianne Lucas-Hourani

    Full Text Available Searching for stimulators of the innate antiviral response is an appealing approach to develop novel therapeutics against viral infections. Here, we established a cell-based reporter assay to identify compounds stimulating expression of interferon-inducible antiviral genes. DD264 was selected out of 41,353 compounds for both its immuno-stimulatory and antiviral properties. While searching for its mode of action, we identified DD264 as an inhibitor of pyrimidine biosynthesis pathway. This metabolic pathway was recently identified as a prime target of broad-spectrum antiviral molecules, but our data unraveled a yet unsuspected link with innate immunity. Indeed, we showed that DD264 or brequinar, a well-known inhibitor of pyrimidine biosynthesis pathway, both enhanced the expression of antiviral genes in human cells. Furthermore, antiviral activity of DD264 or brequinar was found strictly dependent on cellular gene transcription, nuclear export machinery, and required IRF1 transcription factor. In conclusion, the antiviral property of pyrimidine biosynthesis inhibitors is not a direct consequence of pyrimidine deprivation on the virus machinery, but rather involves the induction of cellular immune response.

  17. Lysine biosynthesis in microbes: relevance as drug target and prospects for β-lactam antibiotics production.

    Science.gov (United States)

    Fazius, Felicitas; Zaehle, Christoph; Brock, Matthias

    2013-05-01

    Plants as well as pro- and eukaryotic microorganisms are able to synthesise lysine via de novo synthesis. While plants and bacteria, with some exceptions, rely on variations of the meso-diaminopimelate pathway for lysine biosynthesis, fungi exclusively use the α-aminoadipate pathway. Although bacteria and fungi are, in principle, both suitable as lysine producers, current industrial fermentations rely on the use of bacteria. In contrast, fungi are important producers of β-lactam antibiotics such as penicillins or cephalosporins. The synthesis of these antibiotics strictly depends on α-aminoadipate deriving from lysine biosynthesis. Interestingly, despite the resulting industrial importance of the fungal α-aminoadipate pathway, biochemical reactions leading to α-aminoadipate formation have only been studied on a limited number of fungal species. In this respect, just recently an essential isomerisation reaction required for the formation of α-aminoadipate has been elucidated in detail. This review summarises biochemical pathways leading to lysine production, discusses the suitability of interrupting lysine biosynthesis as target for new antibacterial and antifungal compounds and emphasises on biochemical reactions involved in the formation of α-aminoadipate in fungi as an essential intermediate for both, lysine and β-lactam antibiotics production.

  18. Involvement of lipids in dimethoate-induced inhibition of testosterone biosynthesis in rat interstitial cells.

    Science.gov (United States)

    Astiz, Mariana; Hurtado de Catalfo, Graciela E; de Alaniz, María J T; Marra, Carlos Alberto

    2009-08-01

    The mechanism involved in the inhibition of testosterone (Te) biosynthesis after a sub-chronic exposure to low doses of dimethoate (D) was studied in rat interstitial cells (IC). Expression of COX-2 in IC isolated from D-treated rats increased by 44% over C data, while transcription of StAR decreased by approx. 50% and the expression of this protein was diminished by approximately 40%. PGE(2) and PGF(2alpha) were increased by 61 and 78%, respectively. Te concentration decreased by 49% in IC homogenates. Concomitantly, plasma concentration of LH and FSH both increased. Araquidonate (ARA) and C(22) fatty acyl chains in phospholipids from IC mitochondrial fraction decreased by approx. 30% after D treatment. Protein carbonyls, lipoperoxides and nitrite content increased while alpha-tocopherol and the antioxidant capacity of the soluble cellular fraction decreased significantly. Stimulation with h-CG 10 nM overnight failed to overcome the inhibition caused by D on both Te biosynthesis and 3beta- and 17beta-hydroxysteroid dehydrogenases. Decreased Te biosynthesis may be attributed to (1) inhibition of StAR protein activity due to the stimulation of COX-2 and the overproduction of PGF(2alpha), (2) decreased stimulatory effect of ARA on StAR with a subsequent reduction in the availability of CHO for the androgenic pathway, and/or (3) indirect inhibition of steroidogenic enzymes by a lower transcriptional rate caused by elevated PGF(2alpha). Rofecoxib administration prevents the deleterious effect(s) exerted by D.

  19. GCN5 Acetyltransferase Inhibits PGC1α-induced Hepatitis B Virus Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Xiaohui Tian; Fei Zhao; Zhikui Cheng; Ming Zhou; Xiaoguang Zhi; Jiafu Li; Kanghong Hu

    2013-01-01

    Hepatitis B virus (HBV) biosynthesis is primarily restricted to hepatocytes due to the goveming of liver-enriched nuclear receptors (NRs) on viral RNA synthesis.The liver-enriched NR hepatocyte nuclear factor 4α (HNF4α),the key regulator of genes implicated in hepatic glucose metabolism,is also a primary determinant of HBV pregenomic RNA synthesis and HBV replication.Peroxisome proliferator-activated receptor-γ coactivator lα (PGC1α) coactivates and further enhances the effect of HNF4α on HBV biosynthesis.Here,we showed that the acetyltransferase General Control Non-repressed Protein 5 (GCN5) acetylated PGC1α,leading to alteration of PGC1α from a transcriptionally active state into an inactive state.As a result,the coactivation activity of PGClα on HBV transcription and replication was suppressed.Apparently,an acetylation site mutant of PGC 1α (PGC1αR13) still had coactivation activity as GCN5 could not suppress the coactivation activity of the mutant.Moreover,a catalytically inactive acetyltransferase mutant GCN5m,due to the loss of acetylation activity,failed to inhibit the coactivation function of PGC 1α in HBV biosynthesis.Our results demonstrate that GCN5,through its acetyltransferase activity,inhibits PGClα-induced enhancement of HBV transcription and replication both in vitro and in vivo.

  20. A 7-deoxyloganetic acid glucosyltransferase contributes a key step in secologanin biosynthesis in Madagascar periwinkle.

    Science.gov (United States)

    Asada, Keisuke; Salim, Vonny; Masada-Atsumi, Sayaka; Edmunds, Elizabeth; Nagatoshi, Mai; Terasaka, Kazuyoshi; Mizukami, Hajime; De Luca, Vincenzo

    2013-10-01

    Iridoids form a broad and versatile class of biologically active molecules found in thousands of plant species. In addition to the many hundreds of iridoids occurring in plants, some iridoids, such as secologanin, serve as key building blocks in the biosynthesis of thousands of monoterpene indole alkaloids (MIAs) and many quinoline alkaloids. This study describes the molecular cloning and functional characterization of three iridoid glucosyltransfeases (UDP-sugar glycosyltransferase6 [UGT6], UGT7, and UGT8) from Madagascar periwinkle (Catharanthus roseus) with remarkably different catalytic efficiencies. Biochemical analyses reveal that UGT8 possessed a high catalytic efficiency toward its exclusive iridoid substrate, 7-deoxyloganetic acid, making it better suited for the biosynthesis of iridoids in periwinkle than the other two iridoid glucosyltransfeases. The role of UGT8 in the fourth to last step in secologanin biosynthesis was confirmed by virus-induced gene silencing in periwinkle plants, which reduced expression of this gene and resulted in a large decline in secologanin and MIA accumulation within silenced plants. Localization studies of UGT8 using a carborundum abrasion method for RNA extraction show that its expression occurs preferentially within periwinkle leaves rather than in epidermal cells, and in situ hybridization studies confirm that UGT8 is preferentially expressed in internal phloem associated parenchyma cells of periwinkle species.

  1. TiO2 nanoparticle biosynthesis and its physiological effect on mung bean (Vigna radiata L.

    Directory of Open Access Journals (Sweden)

    Ramesh Raliya

    2015-03-01

    Full Text Available TiO2 nanoparticle (NPs biosynthesis is a low cost, ecofriendly approach developed using the fungi Aspergillus flavus TFR 7. To determine whether TiO2 NPs is suitable for nutrient, we conducted a two part study; biosynthesis of TiO2 NP and evaluates their influence on mung bean. The characterized TiO2 NPs were foliar sprayed at 10 mgL−1 concentration on the leaves of 14 days old mung bean plants. A significant improvement was observed in shoot length (17.02%, root length (49.6%, root area (43%, root nodule (67.5%, chlorophyll content (46.4% and total soluble leaf protein (94% as a result of TiO2 NPs application. In the rhizosphere microbial population increased by 21.4–48.1% and activity of acid phosphatase (67.3%, alkaline phosphatase (72%, phytase (64% and dehydrogenase (108.7% enzyme was observed over control in six weeks old plants owing to application of TiO2 NPs. A possible mechanism has also been hypothesized for TiO2 NPs biosynthesis.

  2. Nitric oxide metabolism and indole acetic acid biosynthesis cross-talk in Azospirillum brasilense SM.

    Science.gov (United States)

    Koul, Vatsala; Tripathi, Chandrakant; Adholeya, Alok; Kochar, Mandira

    2015-04-01

    Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators.

  3. Improved in vitro and in vivo collagen biosynthesis by asiaticoside-loaded ultradeformable vesicles.

    Science.gov (United States)

    Paolino, Donatella; Cosco, Donato; Cilurzo, Felisa; Trapasso, Elena; Morittu, Valeria M; Celia, Christian; Fresta, Massimo

    2012-08-20

    The potentiality of ultradeformable vesicles as a possible topical delivery system for asiaticoside, a natural compound obtained from Centella asiatica was evaluated, because this compound exhibits collagen biosynthesis promoting activity. Ultradeformable vesicles were prepared by the extrusion technique; these vesicles were composed of Phospholipon 100 and different molar fractions of sodium cholate as the edge activator. The physicochemical properties of the ultradeformable vesicles were investigated through differential scanning calorimetry and light scattering techniques. The potential cyctotoxicity and biological activity of asiaticoside-loaded ultradeformable vesicles were evaluated on primary human dermal fibroblast cells by determining the extracellular lactic dehydrogenase activity, the cellular viability and the biosynthetic production of collagen. In vitro permeation experiments through human stratum corneum and epidermis membranes were also carried out. Ultradeformable vesicles having sodium cholate molar fraction of 0.2 proved to be the most suitable topical carriers for asiaticoside. A sodium cholate content of >0.2 was observed to be cytotoxic probably due to its co-existence with other lipid aggregates, an example being mixed micelles. Asiaticoside-loaded ultradeformable vesicles with a sodium cholate molar fraction of 0.2 elicited the greatest degree of collagen biosynthesis in human fibroblasts. Ultradeformable vesicles provided the greatest in vitro skin permeation of asiaticoside showing a 10-fold increase with respect to the free drug solution and favoured an increase in in vivo collagen biosynthesis. Ultradeformable vesicles are therefore suitable carriers for the pharmaceutical and cosmetic application of the natural agent asiaticoside.

  4. Dietary Polyunsaturated Fatty Acids and Inflammation: The Role of Phospholipid Biosynthesis

    Science.gov (United States)

    Raphael, William; Sordillo, Lorraine M.

    2013-01-01

    The composition of fatty acids in the diets of both human and domestic animal species can regulate inflammation through the biosynthesis of potent lipid mediators. The substrates for lipid mediator biosynthesis are derived primarily from membrane phospholipids and reflect dietary fatty acid intake. Inflammation can be exacerbated with intake of certain dietary fatty acids, such as some ω-6 polyunsaturated fatty acids (PUFA), and subsequent incorporation into membrane phospholipids. Inflammation, however, can be resolved with ingestion of other fatty acids, such as ω-3 PUFA. The influence of dietary PUFA on phospholipid composition is influenced by factors that control phospholipid biosynthesis within cellular membranes, such as preferential incorporation of some fatty acids, competition between newly ingested PUFA and fatty acids released from stores such as adipose, and the impacts of carbohydrate metabolism and physiological state. The objective of this review is to explain these factors as potential obstacles to manipulating PUFA composition of tissue phospholipids by specific dietary fatty acids. A better understanding of the factors that influence how dietary fatty acids can be incorporated into phospholipids may lead to nutritional intervention strategies that optimize health. PMID:24152446

  5. Transcriptome and biochemical analyses revealed a detailed proanthocyanidin biosynthesis pathway in brown cotton fiber.

    Directory of Open Access Journals (Sweden)

    Yue-Hua Xiao

    Full Text Available Brown cotton fiber is the major raw material for colored cotton industry. Previous studies have showed that the brown pigments in cotton fiber belong to proanthocyanidins (PAs. To clarify the details of PA biosynthesis pathway in brown cotton fiber, gene expression profiles in developing brown and white fibers were compared via digital gene expression profiling and qRT-PCR. Compared to white cotton fiber, all steps from phenylalanine to PA monomers (flavan-3-ols were significantly up-regulated in brown fiber. Liquid chromatography mass spectrometry analyses showed that most of free flavan-3-ols in brown fiber were in 2, 3-trans form (gallocatechin and catechin, and the main units of polymeric PAs were trihydroxylated on B ring. Consistent with monomeric composition, the transcript levels of flavonoid 3', 5'-hydroxylase and leucoanthocyanidin reductase in cotton fiber were much higher than their competing enzymes acting on the same substrates (dihydroflavonol 4-reductase and anthocyanidin synthase, respectively. Taken together, our data revealed a detailed PA biosynthesis pathway wholly activated in brown cotton fiber, and demonstrated that flavonoid 3', 5'-hydroxylase and leucoanthocyanidin reductase represented the primary flow of PA biosynthesis in cotton fiber.

  6. Silicon promotes cytokinin biosynthesis and delays senescence in Arabidopsis and Sorghum.

    Science.gov (United States)

    Markovich, Oshry; Steiner, Evyatar; Kouřil, Štěpán; Tarkowski, Petr; Aharoni, Asaph; Elbaum, Rivka

    2017-01-19

    Silicate minerals are dominant soil components. Thus, plant roots are constantly exposed to silicic acid. High silicon intake, enabled by root silicon transporters, correlates with increased tolerance to many biotic and abiotic stresses. However, the underlying protection mechanisms are largely unknown. Here, we tested the hypothesis that silicon interacts with the plant hormones, and specifically, that silicic acid intake increases cytokinin biosynthesis. The reaction of sorghum (Sorghum bicolor) and Arabidopsis plants, modified to absorb high versus low amounts of silicon, to dark-induced senescence was monitored, by quantifying expression levels of genes along the senescence pathway and measuring tissue cytokinin levels. In both species, detached leaves with high silicon content senesced more slowly than leaves that were not exposed to silicic acid. Expression levels of genes along the senescence pathway suggested increased cytokinin biosynthesis with silicon exposure. Mass spectrometry measurements of cytokinin suggested a positive correlation between silicon exposure and active cytokinin concentrations. Our results indicate a similar reaction to silicon treatment in distantly related plants, proposing a general function of silicon as a stress reliever, acting via increased cytokinin biosynthesis.

  7. A type 2 diacylglycerol acyltransferase accelerates the triacylglycerol biosynthesis in heterokont oleaginous microalga Nannochloropsis oceanica.

    Science.gov (United States)

    Li, Da-Wei; Cen, Shi-Ying; Liu, Yu-Hong; Balamurugan, Srinivasan; Zheng, Xin-Yan; Alimujiang, Adili; Yang, Wei-Dong; Liu, Jie-Sheng; Li, Hong-Ye

    2016-07-10

    Oleaginous microalgae have received a considerable attention as potential biofuel feedstock. However, lack of industry-suitable strain with lipid rich biomass limits its commercial applications. Targeted engineering of lipogenic pathways represents a promising strategy to enhance the efficacy of microalgal oil production. In this study, a type 2 diacylglycerol acyltransferase (DGAT), a rate-limiting enzyme in triacylglycerol (TAG) biosynthesis, was identified and overexpressed in heterokont oleaginous microalga Nannochloropsis oceanica for the first time. Overexpression of DGAT2 in Nannochloropsis increased the relative transcript abundance by 3.48-fold in engineered microalgae cells. TAG biosynthesis was subsequently accelerated by DGAT2 overexpression and neutral lipid content was significantly elevated by 69% in engineered microalgae. The fatty acid profile determined by GC-MS revealed that fatty acid composition was altered in engineered microalgae. Saturated fatty acids and polyunsaturated fatty acids were found to be increased whereas monounsaturated fatty acids content decreased. Furthermore, DGAT2 overexpression did not show negative impact on algal growth parameters. The present investigation showed that the identified DGAT2 would be a potential candidate for enhancing TAG biosynthesis and might facilitate the development of promising oleaginous strains with industrial potential.

  8. Effects of brassinazole, an inhibitor of brassinosteroid biosynthesis, on light- and dark-grown Chlorella vulgaris.

    Science.gov (United States)

    Bajguz, Andrzej; Asami, Tadao

    2004-03-01

    Treatment of cultured Chlorella vulgaris Beijerinck cells with 0.1-10 microM brassinazole (Brz2001), an inhibitor of brassinosteroid (BR) biosynthesis, inhibits their growth during the first 48 h of cultivation in the light. This inhibition is prevented by the co-application of BR. This result suggests that the presence of endogenous BRs during the initial steps of the C. vulgaris cell cycle is indispensable for their normal growth in the light. In darkness, a treatment with 10 nM brassinolide (BL) promotes growth through the first 24 h of culture, but during the following 24 h the cells undergo complete stagnation. Treatment of dark-grown cells with either Brz2001 alone, or a mixture of 10 nM BL and 0.1/10 microM Brz2001, also stimulates their growth. The effects of treatment with 10 nM BL mixed with 0.1-10 microM of a mevalonate-pathway inhibitor (mevinolin), or a non-mevalonate-pathway inhibitor (clomazone), were also investigated. Mevinolin at these concentrations did not inhibit growth of C. vulgaris; however, clomazone did. Addition of BL overcame the inhibition. These results suggest that the mevalonate pathway does not function in C. vulgaris, and that the non-mevalonate pathway for isopentenyl diphosphate biosynthesis is responsible for the synthesis of one of the primary precursors in BR biosynthesis.

  9. Analysis of putative nonulosonic acid biosynthesis pathways in Archaea reveals a complex evolutionary history.

    Science.gov (United States)

    Kandiba, Lina; Eichler, Jerry

    2013-08-01

    Sialic acids and the other nonulosonic acid sugars, legionaminic acid and pseudaminic acid, are nine carbon-containing sugars that can be detected as components of the glycans decorating proteins and other molecules in Eukarya and Bacteria. Yet, despite the prevalence of N-glycosylation in Archaea and the variety of sugars recruited for the archaeal version of this post-translational modification, only a single report of a nonulosonic acid sugar in an archaeal N-linked glycan has appeared. Hence, to obtain a clearer picture of nonulosonic acid sugar biosynthesis capability in Archaea, 122 sequenced genomes were scanned for the presence of genes involved in the biogenesis of these sugars. The results reveal that while Archaea and Bacteria share a common route of sialic acid biosynthesis, numerous archaeal nonulosonic acid sugar biosynthesis pathway components were acquired from elsewhere via various routes. Still, the limited number of Archaea encoding components involved in the synthesis of nonulosonic acid sugars implies that such saccharides are not major components of glycans in this domain.

  10. Binary Stress Induces an Increase in Indole Alkaloid Biosynthesis in Catharanthus roseus

    Directory of Open Access Journals (Sweden)

    Wei eZhu

    2015-07-01

    Full Text Available Catharanthus roseus is an important medicinal plant, which produces a variety of indole alkaloids of significant pharmaceutical relevance. In the present study, we aimed to investigate the potential stress-induced increase of indole alkaloid biosynthesis in C. roseus using proteomic technique. The contents of the detectable alkaloids ajmalicine, vindoline, catharanthine, and strictosidine in C. roseus were significantly increased under binary stress. Proteomic analysis revealed that the abundance of proteins related to tricarboxylic acid cycle and cell wall was largely increased; while, that of proteins related to tetrapyrrole synthesis and photosynthesis was decreased. Of note, 10-hydroxygeraniol oxidoreductase, which is involved in the biosynthesis of indole alkaloid was two-fold more abundant in treated group compared to that in control. In addition, mRNA expression levels of genes involved in the indole alkaloid biosynthetic pathway indicated an up-regulation in their transcription in C. roseus under UV-B irradiation. These results suggest that binary stress might negatively affect the process of photosynthesis in C. roseus. In addition, the induction of alkaloid biosynthesis appears to be responsive to binary stress.

  11. The PhoP transcription factor negatively regulates avermectin biosynthesis in Streptomyces avermitilis.

    Science.gov (United States)

    Yang, Renjun; Liu, Xingchao; Wen, Ying; Song, Yuan; Chen, Zhi; Li, Jilun

    2015-12-01

    Bacteria sense and respond to the stress of phosphate limitation, anticipating Pi deletion/starvation via the two-component PhoR-PhoP system. The role of the response regulator PhoP in primary metabolism and avermectin biosynthesis in Streptomyces avermitilis was investigated. In response to phosphate starvation, S. avermitilis PhoP, like Streptomyces coelicolor and Streptomyces lividans PhoP, activates the expression of phoRP, phoU, and pstS by binding to the PHO boxes in their promoter regions. Avermectin biosynthesis was significantly increased in ΔphoP deletion mutants. Electrophoretic mobility gel shift assay (EMSA) and DNase I footprinting assays showed that PhoP can bind to a PHO box formed by two direct repeat units of 11 nucleotides located downstream of the transcriptional start site of aveR. By negatively regulating the transcription of aveR, PhoP directly affects avermectin biosynthesis in S. avermitilis. PhoP indirectly affects melanogenesis on Casaminoacids Minimal Medium (MMC) lacking supplemental phosphate. Nitrogen metabolism and some key genes involved in morphological differentiation and antibiotic production in S. avermitilis are also under the control of PhoP.

  12. Engineering a microbial platform for de novo biosynthesis of diverse methylxanthines.

    Science.gov (United States)

    McKeague, Maureen; Wang, Yen-Hsiang; Cravens, Aaron; Win, Maung Nyan; Smolke, Christina D

    2016-11-01

    Engineered microbial biosynthesis of plant natural products can support manufacturing of complex bioactive molecules and enable discovery of non-naturally occurring derivatives. Purine alkaloids, including caffeine (coffee), theophylline (antiasthma drug), theobromine (chocolate), and other methylxanthines, play a significant role in pharmacology and food chemistry. Here, we engineered the eukaryotic microbial host Saccharomyces cerevisiae for the de novo biosynthesis of methylxanthines. We constructed a xanthine-to-xanthosine conversion pathway in native yeast central metabolism to increase endogenous purine flux for the production of 7-methylxanthine, a key intermediate in caffeine biosynthesis. Yeast strains were further engineered to produce caffeine through expression of several enzymes from the coffee plant. By expressing combinations of different N-methyltransferases, we were able to demonstrate re-direction of flux to an alternate pathway and develop strains that support the production of diverse methylxanthines. We achieved production of 270μg/L, 61μg/L, and 3700μg/L of caffeine, theophylline, and 3-methylxanthine, respectively, in 0.3-L bench-scale batch fermentations. The constructed strains provide an early platform for de novo production of methylxanthines and with further development will advance the discovery and synthesis of xanthine derivatives.

  13. Biosynthesis of Polyunsaturated Fatty Acids in Marine Invertebrates: Recent Advances in Molecular Mechanisms

    Science.gov (United States)

    Monroig, Óscar; Tocher, Douglas R.; Navarro, Juan C.

    2013-01-01

    Virtually all polyunsaturated fatty acids (PUFA) originate from primary producers but can be modified by bioconversions as they pass up the food chain in a process termed trophic upgrading. Therefore, although the main primary producers of PUFA in the marine environment are microalgae, higher trophic levels have metabolic pathways that can produce novel and unique PUFA. However, little is known about the pathways of PUFA biosynthesis and metabolism in the levels between primary producers and fish that are largely filled by invertebrates. It has become increasingly apparent that, in addition to trophic upgrading, de novo synthesis of PUFA is possible in some lower animals. The unequivocal identification of PUFA biosynthetic pathways in many invertebrates is complicated by the presence of other organisms within them. These organisms include bacteria and algae with PUFA biosynthesis pathways, and range from intestinal flora to symbiotic relationships that can involve PUFA translocation to host organisms. This emphasizes the importance of studying biosynthetic pathways at a molecular level, and the continual expansion of genomic resources and advances in molecular analysis is facilitating this. The present paper highlights recent research into the molecular and biochemical mechanisms of PUFA biosynthesis in marine invertebrates, particularly focusing on cephalopod molluscs. PMID:24152561

  14. The mbo operon is specific and essential for biosynthesis of mangotoxin in Pseudomonas syringae.

    Science.gov (United States)

    Carrión, Víctor J; Arrebola, Eva; Cazorla, Francisco M; Murillo, Jesús; de Vicente, Antonio

    2012-01-01

    Mangotoxin is an antimetabolite toxin produced by certain Pseudomonas syringae pv. syringae strains. This toxin is an oligopeptide that inhibits ornithine N-acetyl transferase, a key enzyme in the biosynthesis of ornithine and arginine. Previous studies have reported the involvement of the putative nonribosomal peptide synthetase MgoA in virulence and mangotoxin production. In this study, we analyse a new chromosomal region of P. syringae pv. syringae UMAF0158, which contains six coding sequences arranged as an operon (mbo operon). The mbo operon was detected in only mangotoxin-producing strains, and it was shown to be essential for the biosynthesis of this toxin. Mutants in each of the six ORFs of the mbo operon were partially or completely impaired in the production of the toxin. In addition, Pseudomonas spp. mangotoxin non-producer strains transformed with the mbo operon gained the ability to produce mangotoxin, indicating that this operon contains all the genetic information necessary for mangotoxin biosynthesis. The generation of a single transcript for the mbo operon was confirmed and supported by the allocation of a unique promoter and Rho-independent terminator. The phylogenetic analysis of the P. syringae strains harbouring the mbo operon revealed that these strains clustered together.

  15. Dietary Polyunsaturated Fatty Acids and Inflammation: The Role of Phospholipid Biosynthesis

    Directory of Open Access Journals (Sweden)

    Lorraine M. Sordillo

    2013-10-01

    Full Text Available The composition of fatty acids in the diets of both human and domestic animal species can regulate inflammation through the biosynthesis of potent lipid mediators. The substrates for lipid mediator biosynthesis are derived primarily from membrane phospholipids and reflect dietary fatty acid intake. Inflammation can be exacerbated with intake of certain dietary fatty acids, such as some ω-6 polyunsaturated fatty acids (PUFA, and subsequent incorporation into membrane phospholipids. Inflammation, however, can be resolved with ingestion of other fatty acids, such as ω-3 PUFA. The influence of dietary PUFA on phospholipid composition is influenced by factors that control phospholipid biosynthesis within cellular membranes, such as preferential incorporation of some fatty acids, competition between newly ingested PUFA and fatty acids released from stores such as adipose, and the impacts of carbohydrate metabolism and physiological state. The objective of this review is to explain these factors as potential obstacles to manipulating PUFA composition of tissue phospholipids by specific dietary fatty acids. A better understanding of the factors that influence how dietary fatty acids can be incorporated into phospholipids may lead to nutritional intervention strategies that optimize health.

  16. Effects of TiO2 and Ag nanoparticles on polyhydroxybutyrate biosynthesis by activated sludge bacteria.

    Science.gov (United States)

    Priester, John H; Van De Werfhorst, Laurie C; Ge, Yuan; Adeleye, Adeyemi S; Tomar, Shivira; Tom, Lauren M; Piceno, Yvette M; Andersen, Gary L; Holden, Patricia A

    2014-12-16

    Manufactured nanomaterials (MNMs) are increasingly incorporated into consumer products that are disposed into sewage. In wastewater treatment, MNMs adsorb to activated sludge biomass where they may impact biological wastewater treatment performance, including nutrient removal. Here, we studied MNM effects on bacterial polyhydroxyalkanoate (PHA), specifically polyhydroxybutyrate (PHB), biosynthesis because of its importance to enhanced biological phosphorus (P) removal (EBPR). Activated sludge was sampled from an anoxic selector of a municipal wastewater treatment plant (WWTP), and PHB-containing bacteria were concentrated by density gradient centrifugation. After starvation to decrease intracellular PHB stores, bacteria were nutritionally augmented to promote PHB biosynthesis while being exposed to either MNMs (TiO2 or Ag) or to Ag salts (each at a concentration of 5 mg L(-1)). Cellular PHB concentration and PhyloChip community composition were analyzed. The final bacterial community composition differed from activated sludge, demonstrating that laboratory enrichment was selective. Still, PHB was synthesized to near-activated sludge levels. Ag salts altered final bacterial communities, although MNMs did not. PHB biosynthesis was diminished with Ag (salt or MNMs), indicating the potential for Ag-MNMs to physiologically impact EBPR through the effects of dissolved Ag ions on PHB producers.

  17. Transcriptome Analysis of Thapsia laciniata Rouy Provides Insights into Terpenoid Biosynthesis and Diversity in Apiaceae

    Directory of Open Access Journals (Sweden)

    Henrik Toft Simonsen

    2013-04-01

    Full Text Available Thapsia laciniata Rouy (Apiaceae produces irregular and regular sesquiterpenoids with thapsane and guaiene carbon skeletons, as found in other Apiaceae species. A transcriptomic analysis utilizing Illumina next-generation sequencing enabled the identification of novel genes involved in the biosynthesis of terpenoids in Thapsia. From 66.78 million HQ paired-end reads obtained from T. laciniata roots, 64.58 million were assembled into 76,565 contigs (N50: 1261 bp. Seventeen contigs were annotated as terpene synthases and five of these were predicted to be sesquiterpene synthases. Of the 67 contigs annotated as cytochromes P450, 18 of these are part of the CYP71 clade that primarily performs hydroxylations of specialized metabolites. Three contigs annotated as aldehyde dehydrogenases grouped phylogenetically with the characterized ALDH1 from Artemisia annua and three contigs annotated as alcohol dehydrogenases grouped with the recently described ADH1 from A. annua. ALDH1 and ADH1 were characterized as part of the artemisinin biosynthesis. We have produced a comprehensive EST dataset for T. laciniata roots, which contains a large sample of the T. laciniata transcriptome. These transcriptome data provide the foundation for future research into the molecular basis for terpenoid biosynthesis in Thapsia and on the evolution of terpenoids in Apiaceae.

  18. Comparative Transcriptome Analysis Reveals Effects of Exogenous Hematin on Anthocyanin Biosynthesis during Strawberry Fruit Ripening

    Science.gov (United States)

    Li, Huayin; Li, Jingjuan; Zhang, Yihui

    2016-01-01

    Anthocyanin in strawberries has a positive effect on fruit coloration. In this study, the role of exogenous hematin on anthocyanin biosynthesis was investigated. Our result showed that the white stage of strawberries treated with exogenous hematin had higher anthocyanin content, compared to the control group. Among all treatments, 5 μM of hematin was the optimal condition to promote color development. In order to explore the molecular mechanism of fruit coloring regulated by hematin, transcriptomes in the hematin- and non-hematin-treated fruit were analyzed. A large number of differentially expressed genes (DEGs) were identified in regulating anthocyanin synthesis, including the DEGs involved in anthocyanin biosynthesis, hormone signaling transduction, phytochrome signaling, starch and sucrose degradation, and transcriptional pathways. These regulatory networks may play an important role in regulating the color process of strawberries treated with hematin. In summary, exogenous hematin could promote fruit coloring by increasing anthocyanin content in the white stage of strawberries. Furthermore, transcriptome analysis suggests that hematin-promoted fruit coloring occurs through multiple related metabolic pathways, which provides valuable information for regulating fruit color via anthocyanin biosynthesis in strawberries. PMID:28074176

  19. Integration of Transcriptome and Proteome Reveals the Alkaloids Biosynthesis in Macleaya cordata and Macleaya microcarpa

    Institute of Scientific and Technical Information of China (English)

    Yisong Liu; Wei Liu; Xiubing Liu; Peng Huang; Pengcheng Zhu; Pi Cheng; Jing Zeng

    2012-01-01

    The Macleaya spp.,including Macleaya cordata and Macleaya microcarpa,are traditional anti-virus,inflammation eliminating,and insecticide herb medicines for their isoquinoline alkaloids.The studies of their alkaloids biosyntheses are urgent for better application.To further characterize their alkaloids biosyntheses,we elaborately designed the transcriptome,proteome and metabolism profiling for 10 samples of both species to explore their alkaloids biosyntheses.From the transcriptome data,we obtained 69367 and 78255 unigenes for M.cordata and M.microcarpa,which two thirds of them were similar to sequences in public databases.By metabolism profiling,we observed reverse patterns in different organs of two species for alkaloids sanguinarine,chelerythrine,protopine,and allocryptopine.Thus,the expression of enzymes in alkaloid biosynthesis pathways and the differential gene expression for multiple interesting comparisons were analyzed.We identified more than 1000 proteins and hundreds of differentially expressed proteins from iTRAQ proteome data.Furthermore,the ultrastructure of laticifers by SEM proved the alkaloids accumulation in the mature roots.This study suggests strongly that root maybe the organ for major alkaloids biosynthesis.Except for biosynthesis,the alkaloids storage and transport were also important for their accumulation.This work provided the first genome scale analysis for Macleaya spp.and shed light on researches for non-model plants by integrating different high-throughput technologies.

  20. Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants.

    Science.gov (United States)

    Rogalski, Marcelo; Carrer, Helaine

    2011-06-01

    The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation.

  1. The Origin and Biosynthesis of the Benzenoid Moiety of Ubiquinone (Coenzyme Q) in Arabidopsis.

    Science.gov (United States)

    Block, Anna; Widhalm, Joshua R; Fatihi, Abdelhak; Cahoon, Rebecca E; Wamboldt, Yashitola; Elowsky, Christian; Mackenzie, Sally A; Cahoon, Edgar B; Chapple, Clint; Dudareva, Natalia; Basset, Gilles J

    2014-05-01

    It is not known how plants make the benzenoid ring of ubiquinone, a vital respiratory cofactor. Here, we demonstrate that Arabidopsis thaliana uses for that purpose two separate biosynthetic branches stemming from phenylalanine and tyrosine. Gene network modeling and characterization of T-DNA mutants indicated that acyl-activating enzyme encoded by At4g19010 contributes to the biosynthesis of ubiquinone specifically from phenylalanine. CoA ligase assays verified that At4g19010 prefers para-coumarate, ferulate, and caffeate as substrates. Feeding experiments demonstrated that the at4g19010 knockout cannot use para-coumarate for ubiquinone biosynthesis and that the supply of 4-hydroxybenzoate, the side-chain shortened version of para-coumarate, can bypass this blockage. Furthermore, a trans-cinnamate 4-hydroxylase mutant, which is impaired in the conversion of trans-cinnamate into para-coumarate, displayed similar defects in ubiquinone biosynthesis to that of the at4g19010 knockout. Green fluorescent protein fusion experiments demonstrated that At4g19010 occurs in peroxisomes, resulting in an elaborate biosynthetic architecture where phenylpropanoid intermediates have to be transported from the cytosol to peroxisomes and then to mitochondria where ubiquinone is assembled. Collectively, these results demonstrate that At4g19010 activates the propyl side chain of para-coumarate for its subsequent β-oxidative shortening. Evidence is shown that the peroxisomal ABCD transporter (PXA1) plays a critical role in this branch.

  2. In vivo kinetic analysis of the penicillin biosynthesis pathway using PAA stimulus response experiments.

    Science.gov (United States)

    Deshmukh, Amit T; Verheijen, Peter J T; Maleki Seifar, Reza; Heijnen, Joseph J; van Gulik, Walter M

    2015-11-01

    In this study we combined experimentation with mathematical modeling to unravel the in vivo kinetic properties of the enzymes and transporters of the penicillin biosynthesis pathway in a high yielding Penicillium chrysogenum strain. The experiment consisted of a step response experiment with the side chain precursor phenyl acetic acid (PAA) in a glucose-limited chemostat. The metabolite data showed that in the absence of PAA all penicillin pathway enzymes were expressed, leading to the production of a significant amount of 6-aminopenicillanic acid (6APA) as end product. After the stepwise perturbation with PAA, the pathway produced PenG within seconds. From the extra- and intracellular metabolite measurements, hypotheses for the secretion mechanisms of penicillin pathway metabolites were derived. A dynamic model of the penicillin biosynthesis pathway was then constructed that included the formation and transport over the cytoplasmic membrane of pathway intermediates, PAA and the product penicillin-G (PenG). The model parameters and changes in the enzyme levels of the penicillin biosynthesis pathway under in vivo conditions were simultaneously estimated using experimental data obtained at three different timescales (seconds, minutes, hours). The model was applied to determine changes in the penicillin pathway enzymes in time, calculate fluxes and analyze the flux control of the pathway. This led to a reassessment of the in vivo behavior of the pathway enzymes and in particular Acyl-CoA:Isopenicillin N Acyltransferase (AT).

  3. Identification of novel bacterial histidine biosynthesis inhibitors using docking, ensemble rescoring, and whole-cell assays.

    Science.gov (United States)

    Henriksen, S T; Liu, J; Estiu, G; Oltvai, Z N; Wiest, O

    2010-07-15

    The rapid spread on multidrug-resistant strains of Staphylococcus aureus requires not just novel treatment options, but the development of faster methods for the identification of new hits for drug development. The exponentially increasing speed of computational methods makes a more extensive use in the early stages of drug discovery attractive if sufficient accuracy can be achieved. Computational target identification using systems-level methods suggested the histidine biosynthesis pathway as an attractive target against S. aureus. Potential inhibitors for the pathway were identified through docking, followed by ensemble rescoring, that is sufficiently accurate to justify immediate testing of the identified compounds by whole-cell assays, avoiding the need for time-consuming and often difficult intermediary enzyme assays. This novel strategy is demonstrated for three key enzymes of the S. aureus histidine biosynthesis pathway, which is predicted to be essential for bacterial biomass productions. Virtual screening of a library of approximately 10(6) compounds identified 49 potential inhibitors of three enzymes of this pathway. Eighteen representative compounds were directly tested on three S. aureus- and two Escherichia coli strains in standard disk inhibition assays. Thirteen compounds are inhibitors of some or all of the S. aureus strains, while 14 compounds weakly inhibit growth in one or both E. coli strains. The high hit rate obtained from a fast virtual screen demonstrates the applicability of this novel strategy to the histidine biosynthesis pathway.

  4. "Glucose and ethanol-dependent transcriptional regulation of the astaxanthin biosynthesis pathway in Xanthophyllomyces dendrorhous"

    Directory of Open Access Journals (Sweden)

    Cifuentes Víctor

    2011-08-01

    Full Text Available Abstract Background The yeast Xanthophyllomyces dendrorhous is one of the most promising and economically attractive natural sources of astaxanthin. The biosynthesis of this valuable carotenoid is a complex process for which the regulatory mechanisms remain mostly unknown. Several studies have shown a strong correlation between the carbon source present in the medium and the amount of pigments synthesized. Carotenoid production is especially low when high glucose concentrations are used in the medium, while a significant increase is observed with non-fermentable carbon sources. However, the molecular basis of this phenomenon has not been established. Results In this work, we showed that glucose caused transcriptional repression of the three genes involved in the synthesis of astaxanthin from geranylgeranyl pyrophosphate in X. dendrorhous, which correlates with a complete inhibition of pigment synthesis. Strikingly, this regulatory response was completely altered in mutant strains that are incapable of synthesizing astaxanthin. However, we found that addition of ethanol caused the induction of crtYB and crtS gene expression and promoted de novo synthesis of carotenoids. The induction of carotenogenesis was noticeable as early as 24 h after ethanol addition. Conclusion For the first time, we demonstrated that carbon source-dependent regulation of astaxanthin biosynthesis in X. dendrorhous involves changes at the transcriptional level. Such regulatory mechanism provides an explanation for the strong and early inhibitory effect of glucose on the biosynthesis of this carotenoid.

  5. Comparative analysis of anthocyanin biosynthesis during fruit development in two Lycium species.

    Science.gov (United States)

    Zeng, Shaohua; Wu, Min; Zou, Caiyun; Liu, Xiaomin; Shen, Xiaofei; Hayward, Alice; Liu, Chunzhao; Wang, Ying

    2014-04-01

    Dietary consumption of functional foods enriched in anthocyanins benefit for human health by protection against far-ranging human diseases. Delphinidin-derived anthocyanins (valuable as blue pigments and antioxidants) are accumulated specifically in the fruits of Lycium ruthenicum but not in the fruits of Lycium barbarum, suggesting the differences of anthocyanin biosynthesis between the two species. In this study, anthocyanin profiling confirmed that anthocyanins were increasingly accumulated during fruit ripening in L. ruthenicum, and sharply increased at full expanded mature fruit, while no anthocyanin were detected at any stage of L. barbarum fruit development. Several genes involved in anthocyanin biosynthesis were characterized in L. ruthenicum and L. barbarum fruits. Expression profiling of these genes during fruit development showed a significant positive correlation between transcript abundance and anthocyanin accumulation in L. ruthenicum fruit. Meanwhile, transcripts in L. barbarum fruit were either undetectable or were downregulated during fruit ripening, before increasing slightly in the final stages of maturation. In addition, the ratio of LrF3'5H/LrF3'H transcription showed a gradual increase before 6 days after breaker (DAB) and a sharp enhancement at 10 DAB. Our results suggest that the expression patterns of both regulatory and structural genes and the transcriptional ratio of branch-node structural genes F3'5'H/F3'H may determine the phenotypic difference in anthocyanin biosynthesis between L. ruthenicum and L. barbarum fruits.

  6. Characterization of a Pipecolic Acid Biosynthesis Pathway Required for Systemic Acquired Resistance.

    Science.gov (United States)

    Ding, Pingtao; Rekhter, Dmitrij; Ding, Yuli; Feussner, Kirstin; Busta, Lucas; Haroth, Sven; Xu, Shaohua; Li, Xin; Jetter, Reinhard; Feussner, Ivo; Zhang, Yuelin

    2016-10-01

    Systemic acquired resistance (SAR) is an immune response induced in the distal parts of plants following defense activation in local tissue. Pipecolic acid (Pip) accumulation orchestrates SAR and local resistance responses. Here, we report the identification and characterization of SAR-DEFICIENT4 (SARD4), which encodes a critical enzyme for Pip biosynthesis in Arabidopsis thaliana Loss of function of SARD4 leads to reduced Pip levels and accumulation of a Pip precursor, Δ(1)-piperideine-2-carboxylic acid (P2C). In Escherichia coli, expression of the aminotransferase ALD1 leads to production of P2C and addition of SARD4 results in Pip production, suggesting that a Pip biosynthesis pathway can be reconstituted in bacteria by coexpression of ALD1 and SARD4. In vitro experiments showed that ALD1 can use l-lysine as a substrate to produce P2C and P2C is converted to Pip by SARD4. Analysis of sard4 mutant plants showed that SARD4 is required for SAR as well as enhanced pathogen resistance conditioned by overexpression of the SAR regulator FLAVIN-DEPENDENT MONOOXYGENASE1. Compared with the wild type, pathogen-induced Pip accumulation is only modestly reduced in the local tissue of sard4 mutant plants, but it is below detection in distal leaves, suggesting that Pip is synthesized in systemic tissue by SARD4-mediated reduction of P2C and biosynthesis of Pip in systemic tissue contributes to SAR establishment.

  7. Where does N(ε-trimethyllysine for the carnitine biosynthesis in mammals come from?

    Directory of Open Access Journals (Sweden)

    Luigi Servillo

    Full Text Available N(ε-trimethyllysine (TML is a non-protein amino acid which takes part in the biosynthesis of carnitine. In mammals, the breakdown of endogenous proteins containing TML residues is recognized as starting point for the carnitine biosynthesis. Here, we document that one of the main sources of TML could be the vegetables which represent an important part of daily alimentation for most mammals. A HPLC-ESI-MS/MS method, which we previously developed for the analysis of N(G-methylarginines, was utilized to quantitate TML in numerous vegetables. We report that TML, believed to be rather rare in plants as free amino acid, is, instead, ubiquitous in them and at not negligible levels. The occurrence of TML has been also confirmed in some vegetables by a HPLC method with fluorescence detection. Our results establish that TML can be introduced as free amino acid in conspicuous amounts from vegetables. The current opinion is that mammals utilize the breakdown of their endogenous proteins containing TML residues as starting point for carnitine biosynthesis. However, our finding raises the question of whether a tortuous and energy expensive route as the one of TML formation from the breakdown of endogenous proteins is really preferred when the substance is so easily available in vegetable foods. On the basis of this result, it must be taken into account that in mammals TML might be mainly introduced by diet. However, when the alimentary intake becomes insufficient, as during starvation, it might be supplied by endogenous protein breakdown.

  8. Depsipeptide Intermediates Interrogate Proposed Biosynthesis of Cereulide, the Emetic Toxin of Bacillus cereus.

    Science.gov (United States)

    Marxen, Sandra; Stark, Timo D; Rütschle, Andrea; Lücking, Genia; Frenzel, Elrike; Scherer, Siegfried; Ehling-Schulz, Monika; Hofmann, Thomas

    2015-05-27

    Cereulide and isocereulides A-G are biosynthesized as emetic toxins by Bacillus cereus via a non-ribosomal peptide synthetase (NRPS) called Ces. Although a thiotemplate mechanisms involving cyclo-trimerization of ready-made D-O-Leu-D-Ala-L-O-Val-L-Val via a thioesterase (TE) domain is proposed for cereulide biosynthesis, the exact mechanism is far from being understood. UPLC-TOF MS analysis of B. cereus strains in combination with (13)C-labeling experiments now revealed tetra-, octa-, and dodecapeptides of a different sequence, namely (L-O-Val-L-Val-D-O-Leu-D-Ala)1-3, as intermediates of cereulide biosynthesis. Surprisingly, also di-, hexa-, and decadepsipeptides were identified which, together with the structures of the previously reported isocereulides E, F, and G, do not correlate to the currently proposed mechanism for cereulide biosynthesis and violate the canonical NRPS biosynthetic logic. UPLC-TOF MS metabolite analysis and bioinformatic gene cluster analysis highlighted dipeptides rather than single amino or hydroxy acids as the basic modules in tetradepsipeptide assembly and proposed the CesA C-terminal C* domain and the CesB C-terminal TE domain to function as a cooperative esterification and depsipeptide elongation center repeatedly recruiting the action of the C* domain to oligomerize tetradepsipeptides prior to the release of cereulide from the TE domain by macrocyclization.

  9. Effect of zinc on the biosynthesis of tryptophan, indol auxins and gibberellins in barely

    Energy Technology Data Exchange (ETDEWEB)

    Masev, N.; Kutacek, M.

    1966-01-01

    The action of zinc on the growth of barley and the biosynthesis of indol compounds and gibberellin-like substances was investigated in a number of concentrations of zinc from doses stimulating growth to toxic doses. The seeds were soaked before sowing in solutions of zinc sulfate (5 x 10/sup -5/ to 5 x 10/sup -1/% Zn), and the plants cultivated for 7 days in water. Lower concentrations of zinc increased both plant growth and the biosynthesis of tryptophan and auxins. At the optimum concentration of 5 x 10/sup -3/% Zn this increase in tryptophan amounted to 241% of the variant without zinc; in substances with an R/sub F/ corresponding to indolyacetic acid, the increase determined by the biological test, was 207% as against the variant without zinc. Higher concentrations of zinc inhibited growth, the tryptophan content was decreased to below that of the control without zinc and the auxin content also fell to below the control values. Zinc also influenced the content of gibberellin-like substances in the plants. At a concentration of 5 x 10/sup -3/% Zn the increase in the growth activity in the gibberellic acid area of the chromatogram was 294% of the variant without zinc. At toxic concentrations of zinc, the content of gibberellin-like substances fell to below that of the controls. The finding that zinc acts simultaneously on the biosynthesis of auxins and gibberellins is also evidence for the common action of growth substances of various chemical types on plant growth.

  10. Multidrug Transporters and Alterations in Sterol Biosynthesis Contribute to Azole Antifungal Resistance in Candida parapsilosis.

    Science.gov (United States)

    Berkow, Elizabeth L; Manigaba, Kayihura; Parker, Josie E; Barker, Katherine S; Kelly, Stephen L; Rogers, P David

    2015-10-01

    While much is known concerning azole resistance in Candida albicans, considerably less is understood about Candida parapsilosis, an emerging species of Candida with clinical relevance. We conducted a comprehensive analysis of azole resistance in a collection of resistant C. parapsilosis clinical isolates in order to determine which genes might play a role in this process within this species. We examined the relative expression of the putative drug transporter genes CDR1 and MDR1 and that of ERG11. In isolates overexpressing these genes, we sequenced the genes encoding their presumed transcriptional regulators, TAC1, MRR1, and UPC2, respectively. We also sequenced the sterol biosynthesis genes ERG3 and ERG11 in these isolates to find mutations that might contribute to this phenotype in this Candida species. Our findings demonstrate that the putative drug transporters Cdr1 and Mdr1 contribute directly to azole resistance and suggest that their overexpression is due to activating mutations in the genes encoding their transcriptional regulators. We also observed that the Y132F substitution in ERG11 is the only substitution occurring exclusively among azole-resistant isolates, and we correlated this with specific changes in sterol biosynthesis. Finally, sterol analysis of these isolates suggests that other changes in sterol biosynthesis may contribute to azole resistance in C. parapsilosis.

  11. Fluorinated Sterols Are Suicide Inhibitors of Ergosterol Biosynthesis and Growth in Trypanosoma brucei.

    Science.gov (United States)

    Leaver, David J; Patkar, Presheet; Singha, Ujjal K; Miller, Matthew B; Haubrich, Brad A; Chaudhuri, Minu; Nes, W David

    2015-10-22

    Trypanosoma brucei, the causal agent for sleeping sickness, depends on ergosterol for growth. Here, we describe the effects of a mechanism-based inhibitor, 26-fluorolanosterol (26FL), which converts in vivo to a fluorinated substrate of the sterol C24-methyltransferase essential for sterol methylation and function of ergosterol, and missing from the human host. 26FL showed potent inhibition of ergosterol biosynthesis and growth of procyclic and bloodstream forms while having no effect on cholesterol biosynthesis or growth of human epithelial kidney cells. During exposure of cloned TbSMT to 26-fluorocholesta-5,7,24-trienol, the enzyme is gradually killed as a consequence of the covalent binding of the intermediate C25 cation to the active site (kcat/kinact = 0.26 min(-1)/0.24 min(-1); partition ratio of 1.08), whereas 26FL is non-productively bound. These results demonstrate that poisoning of ergosterol biosynthesis by a 26-fluorinated Δ(24)-sterol is a promising strategy for developing a new treatment for trypanosomiasis.

  12. Host-Tree Monoterpenes and Biosynthesis of Aggregation Pheromones in the Bark Beetle Ips paraconfusus

    Directory of Open Access Journals (Sweden)

    John A. Byers

    2012-01-01

    Full Text Available A paradigm developed in the 1970s that Ips bark beetles biosynthesize their aggregation pheromone components ipsenol and ipsdienol by hydroxylating myrcene, a host tree monoterpene. Similarly, host α-pinene was hydroxylated to a third pheromone component cis-verbenol. In 1990, however, we reported that amounts of ipsenol and ipsdienol produced by male Ips paraconfusus (Coleoptera: Scolytinae feeding in five host pine species were nearly the same, even though no detectable myrcene precursor was detected in one of these pines (Pinus sabiniana. Subsequent research showed ipsenol and ipsdienol are also biosynthesized from smaller precursors such as acetate and mevalonate, and this de novo pathway is the major one, while host tree myrcene conversion by the beetle is the minor one. We report concentrations of myrcene, α-pinene and other major monoterpenes in five pine hosts (Pinus ponderosa, P. lambertiana, P. jeffreyi, P. sabiniana, and P. contorta of I. paraconfusus. A scheme for biosynthesis of ipsdienol and ipsenol from myrcene and possible metabolites such as ipsenone is presented. Mass spectra and quantities of ipsenone are reported and its possible role in biosynthesis of aggregation pheromone. Coevolution of bark beetles and host trees is discussed in relation to pheromone biosynthesis, host plant selection/suitability, and plant resistance.

  13. Biosynthesis of threonylcarbamoyl adenosine (t6A), a universal tRNA nucleoside.

    Science.gov (United States)

    Deutsch, Christopher; El Yacoubi, Basma; de Crécy-Lagard, Valérie; Iwata-Reuyl, Dirk

    2012-04-20

    The anticodon stem-loop (ASL) of transfer RNAs (tRNAs) drives decoding by interacting directly with the mRNA through codon/anticodon pairing. Chemically complex nucleoside modifications found in the ASL at positions 34 or 37 are known to be required for accurate decoding. Although over 100 distinct modifications have been structurally characterized in tRNAs, only a few are universally conserved, among them threonylcarbamoyl adenosine (t(6)A), found at position 37 in the anticodon loop of a subset of tRNA. Structural studies predict an important role for t(6)A in translational fidelity, and in vivo work supports this prediction. Although pioneering work in the 1970s identified the fundamental substrates for t(6)A biosynthesis, the enzymes responsible for its biosynthesis have remained an enigma. We report here the discovery that in bacteria four proteins (YgjD, YrdC, YjeE, and YeaZ) are both necessary and sufficient for t(6)A biosynthesis in vitro. Notably, YrdC and YgjD are members of universally conserved families that were ranked among the top 10 proteins of unknown function in need of functional characterization, while YeaZ and YjeE are specific to bacteria. This latter observation, coupled with the essentiality of all four proteins in bacteria, establishes this pathway as a compelling new target for antimicrobial development.

  14. Where does N(ε)-trimethyllysine for the carnitine biosynthesis in mammals come from?

    Science.gov (United States)

    Servillo, Luigi; Giovane, Alfonso; Cautela, Domenico; Castaldo, Domenico; Balestrieri, Maria Luisa

    2014-01-01

    N(ε)-trimethyllysine (TML) is a non-protein amino acid which takes part in the biosynthesis of carnitine. In mammals, the breakdown of endogenous proteins containing TML residues is recognized as starting point for the carnitine biosynthesis. Here, we document that one of the main sources of TML could be the vegetables which represent an important part of daily alimentation for most mammals. A HPLC-ESI-MS/MS method, which we previously developed for the analysis of N(G)-methylarginines, was utilized to quantitate TML in numerous vegetables. We report that TML, believed to be rather rare in plants as free amino acid, is, instead, ubiquitous in them and at not negligible levels. The occurrence of TML has been also confirmed in some vegetables by a HPLC method with fluorescence detection. Our results establish that TML can be introduced as free amino acid in conspicuous amounts from vegetables. The current opinion is that mammals utilize the breakdown of their endogenous proteins containing TML residues as starting point for carnitine biosynthesis. However, our finding raises the question of whether a tortuous and energy expensive route as the one of TML formation from the breakdown of endogenous proteins is really preferred when the substance is so easily available in vegetable foods. On the basis of this result, it must be taken into account that in mammals TML might be mainly introduced by diet. However, when the alimentary intake becomes insufficient, as during starvation, it might be supplied by endogenous protein breakdown.

  15. Genomic Characterization Reveals Insights Into Patulin Biosynthesis and Pathogenicity in Penicillium Species.

    Science.gov (United States)

    Li, Boqiang; Zong, Yuanyuan; Du, Zhenglin; Chen, Yong; Zhang, Zhanquan; Qin, Guozheng; Zhao, Wenming; Tian, Shiping

    2015-06-01

    Penicillium species are fungal pathogens that infect crop plants worldwide. P. expansum differs from P. italicum and P. digitatum, all major postharvest pathogens of pome and citrus, in that the former is able to produce the mycotoxin patulin and has a broader host range. The molecular basis of host-specificity of fungal pathogens has now become the focus of recent research. The present report provides the whole genome sequence of P. expansum (33.52 Mb) and P. italicum (28.99 Mb) and identifies differences in genome structure, important pathogenic characters, and secondary metabolite (SM) gene clusters in Penicillium species. We identified a total of 55 gene clusters potentially related to secondary metabolism, including a cluster of 15 genes (named PePatA to PePatO), that may be involved in patulin biosynthesis in P. expansum. Functional studies confirmed that PePatL and PePatK play crucial roles in the biosynthesis of patulin and that patulin production is not related to virulence of P. expansum. Collectively, P. expansum contains more pathogenic genes and SM gene clusters, in particular, an intact patulin cluster, than P. italicum or P. digitatum. These findings provide important information relevant to understanding the molecular network of patulin biosynthesis and mechanisms of host-specificity in Penicillium species.

  16. Identification and Characterization of Multiple Intermediate Alleles of the Key Genes Regulating Brassinosteroid Biosynthesis Pathways

    Science.gov (United States)

    Du, Junbo; Zhao, Baolin; Sun, Xin; Sun, Mengyuan; Zhang, Dongzhi; Zhang, Shasha; Yang, Wenyu

    2017-01-01

    Most of the early identified brassinosteroid signaling and biosynthetic mutants are null mutants, exhibiting extremely dwarfed phenotypes and male sterility. These null mutants are usually unable to be directly transformed via a routinely used Agrobacterium-mediated gene transformation system and therefore are less useful for genetic characterization of the brassinosteroid (BR)-related pathways. Identification of intermediate signaling mutants such as bri1–5 and bri1–9 has contributed drastically to the elucidation of BR signaling pathway using both genetic and biochemical approaches. However, intermediate mutants of key genes regulating BR biosynthesis have seldom been reported. Here we report identification of several intermediate BR biosynthesis mutants mainly resulted from leaky transcriptions due to the insertions of T-DNAs in the introns. These mutants are semi-dwarfed and fertile and capable to be transformed. These intermediate mutants could be useful tools for future discovery and analyses of novel components regulating BR biosynthesis and catabolism via genetic modifier screen. PMID:28138331

  17. Functional Diversity of Genes for the Biosynthesis of Paeoniflorin and Its Derivatives in Paeonia

    Directory of Open Access Journals (Sweden)

    Luqi Huang

    2013-09-01

    Full Text Available The Paeonia root, with or without bark, are considered vital traditional Chinese medicine materials; the examples are those of Bai Shao, Chi Shao, and Dan Pi. In this study, we examine 24 genes and their expressions involved in the biosynthesis of paeoniflorin and its derivatives, which are active compounds of the Paeonia root, in Paeonia lactiflora and P. suffruticosa, as well as other related plants, Punica granatum, Rhus radicans, and Coriaria nepalensis. Our phylogenetic analyses suggest that these genes have functional diversity, and analysis of the transcriptional level shows paeoniflorin and gallic acid biosynthesis-related genes exhibit different transcription profiles in flowers, carpels, bark-free roots, and bark of P. lactiflora. The correlation analysis of gene expression and active compound contents support the idea that hydroxymethylglutaryl-CoA synthase and phosphomevalonate kinase in the mevalonate pathway and 3-dehydroquinate dehydratase/shikimate dehydrogenase in shikimate biosynthesis are potentially closely related to the accumulation of paeoniflorin and benzoylpaeoniflorin. Coupling gene diversity with chemical analysis, we show that paeoniflorin and its derived aromatic amino acids are predominant in bark.

  18. The biosynthesis, absorption, and origin of cholesterol and plant sterols in the Florida land crab.

    Science.gov (United States)

    Douglass, T S; Connor, W E; Lin, D S

    1981-08-01

    In order to study the biosynthesis, composition, and origin of sterols in the Florida land crabs, Cardisoma guanhumi (Latreille), we fed 17 male crabs either a cholesterol-free or a high cholesterol diet for 2 to 7 weeks. The origin of sterols in these crabs, whether from biosynthesis or from the diet, was determined by tahree procedures: the incorporation of isotopic mevalonate into the cholesterol when the diet was cholesterol-free; the absorption of isotopic cholesterol and sitosterol from the diet; the cholesterol and plant sterol concentrations of hepatopancreas, plasma, and muscle under conditions of cholesterol-free and high cholesterol diets. In addition, the interconversion of cholesterol and sitosterol was investigated. Dietary sterols of plant and animal sources were readily absorbed and provided the major source of sterols for this species of crab. The biosynthesis of cholesterol from mevalonate in this crab was minimal. However, cholesterol was synthesized from dietary sitosterol by dealkylation. Cholesterol and the three plant sterols (24 epsilon-methyl cholesterol, stigmasterol, and sitosterol) were found in the hepatopancreas, plasma, and muscle of the crab. Plant sterols contributed from 9 to 37% of the total sterols in the hepatopancreas, plasma, and muscle of the crabs fed a cholesterol-free diet.

  19. Biosynthesis of antifungal and antibacterial polyketides by Burkholderia gladioli in coculture with Rhizopus microsporus.

    Science.gov (United States)

    Ross, Claudia; Opel, Viktoria; Scherlach, Kirstin; Hertweck, Christian

    2014-12-01

    Fungi-bacteria interactions can impact the course of fungal infection and biotechnological use. The mucoralean fungus Rhizopus microsporus, traditionally used in food fermentations (tempe and sufu), is frequently accompanied by Burkholderia gladioli pv. cocovenenans. When producing tempe bongkrek, the bacterial contamination can lead to lethal food-related intoxications caused by the respiratory toxin bongkrekic acid. To unveil the metabolic potential of the fungus-associated bacterium, we sequenced its genome, assigned secondary metabolite biosynthesis gene clusters and monitored the metabolic profile under various growth conditions. In addition to the bongkrekic acid biosynthesis gene cluster we found gene clusters coding for the biosynthesis of toxoflavin and a complex polyketide. The orphan polyketide synthase gene cluster was activated under conditions that emulate tempe production, which enabled isolation and structure elucidation of four members of the enacyloxin family of antibiotics, out of which one is new. Moreover, we found that the fungus positively influences the growth of the bacteria and dramatically increases bongkrekic acid production in stationary culture, which inhibits the growth of the fungus. These results showcase the context-dependent formation of antifungal and antibacterial agents at the fungal-bacterial interface, which may also serve as a model for scenarios observed in mixed infections.

  20. Elucidation and chemical modulation of sulfolipid-1 biosynthesis in Mycobacterium tuberculosis.

    Science.gov (United States)

    Seeliger, Jessica C; Holsclaw, Cynthia M; Schelle, Michael W; Botyanszki, Zsofia; Gilmore, Sarah A; Tully, Sarah E; Niederweis, Michael; Cravatt, Benjamin F; Leary, Julie A; Bertozzi, Carolyn R

    2012-03-09

    Mycobacterium tuberculosis possesses unique cell-surface lipids that have been implicated in virulence. One of the most abundant is sulfolipid-1 (SL-1), a tetraacyl-sulfotrehalose glycolipid. Although the early steps in SL-1 biosynthesis are known, the machinery underlying the final acylation reactions is not understood. We provide genetic and biochemical evidence for the activities of two proteins, Chp1 and Sap (corresponding to gene loci rv3822 and rv3821), that complete this pathway. The membrane-associated acyltransferase Chp1 accepts a synthetic diacyl sulfolipid and transfers an acyl group regioselectively from one donor substrate molecule to a second acceptor molecule in two successive reactions to yield a tetraacylated product. Chp1 is fully active in vitro, but in M. tuberculosis, its function is potentiated by the previously identified sulfolipid transporter MmpL8. We also show that the integral membrane protein Sap and MmpL8 are both essential for sulfolipid transport. Finally, the lipase inhibitor tetrahydrolipstatin disrupts Chp1 activity in M. tuberculosis, suggesting an avenue for perturbing SL-1 biosynthesis in vivo. These data complete the SL-1 biosynthetic pathway and corroborate a model in which lipid biosynthesis and transmembrane transport are coupled at the membrane-cytosol interface through the activity of multiple proteins, possibly as a macromolecular complex.