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151.
Isoprenoids are the most numerous and structurally diverse family of natural products. Terpenoids, a class of isoprenoids often isolated from plants, are used as commercial flavor and fragrance compounds and antimalarial or anticancer drugs. Because plant tissue extractions typically yield low terpenoid concentrations, we sought an alternative method to produce high-value terpenoid compounds, such as the antimalarial drug artemisinin, in a microbial host. We engineered the expression of a synthetic amorpha-4,11-diene synthase gene and the mevalonate isoprenoid pathway from Saccharomyces cerevisiae in Escherichia coli. Concentrations of amorphadiene, the sesquiterpene olefin precursor to artemisinin, reached 24 microg caryophyllene equivalent/ml. Because isopentenyl and dimethylallyl pyrophosphates are the universal precursors to all isoprenoids, the strains developed in this study can serve as platform hosts for the production of any terpenoid compound for which a terpene synthase gene is available. 相似文献
152.
Zhu B Sánchez J van Alen TA Sanabria J Jetten MS Ettwig KF Kartal B 《Biochemical Society transactions》2011,39(6):1822-1825
Anammox (anaerobic ammonium oxidation) is an environment-friendly and cost-efficient nitrogen-removal process currently applied to high-ammonium-loaded wastewaters such as anaerobic digester effluents. In these wastewaters, dissolved methane is also present and should be removed to prevent greenhouse gas emissions into the environment. Potentially, another recently discovered microbial pathway, n-damo (nitrite-dependent anaerobic methane oxidation) could be used for this purpose. In the present paper, we explore the feasibility of simultaneously removing methane and ammonium anaerobically, starting with granules from a full-scale anammox bioreactor. We describe the development of a co-culture of anammox and n-damo bacteria using a medium containing methane, ammonium and nitrite. The results are discussed in the context of other recent studies on the application of anaerobic methane- and ammonia-oxidizing bacteria for wastewater treatment. 相似文献
153.
Xiao-Qi Zhang Chengdao Li Joe Panozzo Sharon Westcott Guoping Zhang Amy Tay Rudi Appels Mike Jones Reg Lance 《Molecular breeding : new strategies in plant improvement》2011,27(1):1-9
The terminal region of barley chromosome 5HL controls malt extract, diastatic power, free amino acid nitrogen, alpha-amylase activity, seed dormancy and pre-harvest sprouting. Comparative analysis of the barley and rice maps has established that the terminal region of barley chromosome 5HL is syntenic to rice chromosome 3L near the telomere end. The rice BAC (Bacterial Artificial Chromosome) sequences covering the region of chromosome 3L were used to search barley expressed sequenced tags database. Thirty-three genes were amplified by PCR (polymerase chain reaction) with the primers designed from barley ESTs (expressed sequence tag). Comparison of the sequences of the PCR generated DNA fragments revealed polymorphisms including single nucleotide polymorphism (SNP), insertions or deletions between the barley varieties. Seven new PCR based molecular markers were developed and mapped within 10 cM in three doubled haploid barley populations (Stirling × Harrington, Baudin × AC Metcalfe and Chebec × Harrington). The mapped genes maintain the micro-syntenic relationship between barley and rice. These gene specific markers provide simple and efficient tools for germplasm characterization and marker-assisted selection for barley malting quality, and ultimately lead to isolation and identification of the major gene(s) controlling multiple quality traits on barley chromosome 5HL. 相似文献
154.
Jay G. Forsythe Sloane L. English Rachel E. Simoneaux Arthur L. Weber 《Origins of life and evolution of the biosphere》2018,48(2):201-211
A one-pot method was developed for the preparation of a series of β-alanine standards of moderate size (2 to ≥12 residues) for studies concerning the prebiotic origins of peptides. The one-pot synthesis involved two sequential reactions: (1) dry-down self-condensation of β-alanine methyl ester, yielding β-alanine peptide methyl ester oligomers, and (2) subsequent hydrolysis of β-alanine peptide methyl ester oligomers, producing a series of β-alanine peptide standards. These standards were then spiked into a model prebiotic product mixture to confirm by HPLC the formation of β-alanine peptides under plausible reaction conditions. The simplicity of this approach suggests it can be used to prepare a variety of β-peptide standards for investigating differences between α- and β-peptides in the context of prebiotic chemistry. 相似文献
155.
Impaired carotenogenesis can affect organization and functionality of etioplast membranes 总被引:1,自引:0,他引:1
Isabella Moro Francesca Dalla Vecchia Nicoletta La Rocca Flavia Navari-Izzo Mike Frank Quartacci Daniela Di Baccio Wolfhart Rüdiger Nicoletta Rascio 《Physiologia plantarum》2004,122(1):123-132
The effects of impaired carotenogenesis on plastid membrane organization, functionality and stability were studied in etiolated barley plants grown at 20 and 30°C. The plants were treated with norflurazon or amitrole, two herbicides affecting phytoene desaturation and lycopene cyclization, respectively. At 20°C, the amitrole-treated etioplasts, which accumulated lycopene in their inner membranes, exhibited disorganized prolamellar bodies, containing a prevalent form of non-phototransformable protochlorophyllide (Pchlide). They also showed a certain difficulty in reducing the phototransformable pigment to chlorophyllide when exposed to light, and were unable to reform the active ternary complex [protochlorophyllide–oxidoreductase (POR)–Pchlide–NADPH] when placed back in darkness. No ultrastructural alterations were found in norflurazon-treated etioplasts, with carotenogenesis inhibited at the phytoene desaturation step. In these latter organelles, Pchlide, whose forms were comparable with those of the control etioplasts, was photoreduced quickly after illumination and the ternary complex was reformed during a subsequent dark period. Thus, the impaired carotenogenesis leading to the accumulation of lycopene showed greater interference with the etioplast membrane arrangement and functionality than did the earlier interruption of the biosynthetic pathway at the phytoene level. This might be due to the different interactions of the distinct carotenoid precursors with other membrane components. However, in etioplasts of norflurazon-treated plants, a rise in growth temperature caused a partial demolition of prolamellar bodies, showing a lowered thermostability of the carotenoid-deficient membranes. This latter effect strengthens the concept that a correct and complete carotenogenesis pathway, leading to the synthesis of polar carotenoids (i.e. xanthophylls), is required for the maintenance of stable plastid membranes. 相似文献
156.
Minehira K Young SG Villanueva CJ Yetukuri L Oresic M Hellerstein MK Farese RV Horton JD Preitner F Thorens B Tappy L 《Journal of lipid research》2008,49(9):2038-2044
The liver secretes triglyceride-rich VLDLs, and the triglycerides in these particles are taken up by peripheral tissues, mainly heart, skeletal muscle, and adipose tissue. Blocking hepatic VLDL secretion interferes with the delivery of liver-derived triglycerides to peripheral tissues and results in an accumulation of triglycerides in the liver. However, it is unclear how interfering with hepatic triglyceride secretion affects adiposity, muscle triglyceride stores, and insulin sensitivity. To explore these issues, we examined mice that cannot secrete VLDL [due to the absence of microsomal triglyceride transfer protein (Mttp) in the liver]. These mice exhibit markedly reduced levels of apolipoprotein B-100 in the plasma, along with reduced levels of triglycerides in the plasma. Despite the low plasma triglyceride levels, triglyceride levels in skeletal muscle were unaffected. Adiposity and adipose tissue triglyceride synthesis rates were also normal, and body weight curves were unaffected. Even though the blockade of VLDL secretion caused hepatic steatosis accompanied by increased ceramides and diacylglycerols in the liver, the mice exhibited normal glucose tolerance and were sensitive to insulin at the whole-body level, as judged by hyperinsulinemic euglycemic clamp studies. Normal hepatic glucose production and insulin signaling were also maintained in the fatty liver induced by Mttp deletion. Thus, blocking VLDL secretion causes hepatic steatosis without insulin resistance, and there is little effect on muscle triglyceride stores or adiposity. 相似文献
157.
Leah Wetherill Dongbing Lai Emma C. Johnson Andrey Anokhin Lance Bauer Kathleen K. Bucholz Danielle M. Dick Ahmad R. Hariri Victor Hesselbrock Chella Kamarajan John Kramer Samuel Kuperman Jacquelyn L. Meyers John I. Nurnberger Jr Marc Schuckit Denise M. Scott Robert E. Taylor Jay Tischfield Bernice Porjesz Alison M. Goate Howard J. Edenberg Tatiana Foroud Ryan Bogdan Arpana Agrawal 《Genes, Brain & Behavior》2019,18(6)
Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome‐wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European‐Americans (EA; 2927 cases) and 3132 African‐Americans (AA: 1315 cases) participating in the family‐based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h 2 in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome‐wide significant (GWS; P < 5E‐08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion‐deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans‐ancestral meta‐analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward‐related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non‐European samples with distinct patterns of substance use may lead to the identification of novel ancestry‐specific genetic markers of risk. 相似文献
158.
Modeled microgravity disrupts collagen I/integrin signaling during osteoblastic differentiation of human mesenchymal stem cells 总被引:6,自引:0,他引:6
Meyers VE Zayzafoon M Gonda SR Gathings WE McDonald JM 《Journal of cellular biochemistry》2004,93(4):697-707
Spaceflight leads to reduced bone mineral density in weight bearing bones that is primarily attributed to a reduction in bone formation. We have previously demonstrated severely reduced osteoblastogenesis of human mesenchymal stem cells (hMSC) following 7 days culture in modeled microgravity (MMG). One potential mechanism for reduced osteoblastic differentiation is disruption of type I collagen (Col I)-integrin interactions and reduced integrin signaling. Integrins are heterodimeric transmembrane receptors that bind extracellular matrix (ECM) proteins and produce signals essential for proper cellular function, survival, and differentiation. Therefore, we investigated the effects of MMG on integrin expression and function in hMSC. We demonstrate that 7 days of culture in MMG leads to reduced expression of the ECM protein, Col I. Conversely, MMG consistently increases Col I-specific alpha2 and beta1 integrin protein expression. Despite this increase in integrin subunit expression, autophosphorylation of adhesion-dependent kinases, focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (PYK2), is significantly reduced. Activation of Akt protein kinase (Akt) is unaffected by the reduction in FAK activation. However, reduced downstream signaling via the Ras-mitogen activated protein kinase (MAPK) pathway is evidenced by a reduction in Ras and extracellular signal-related protein kinase (ERK) activation. Taken together, our findings indicate that MMG decreases integrin/MAPK signaling, which likely contributes to the observed reduction in osteoblastogenesis. 相似文献
159.
Evidence that an imprinted gene on the X chromosome increases ovulation rate in sheep 总被引:1,自引:0,他引:1
Ovulation rate records from 1311 female progeny of 50 Coopworth rams were used to study the inheritance of ovulation rate in a screened high prolificacy sheep flock. Breeding values (BV) for ovulation rate for 33 sires used within the screened flock and ovulation rate deviations for a further 17 sires progeny tested in commercial flocks suggest that a major gene (WOODLANDS: gene) for ovulation rate with a non-Mendelian inheritance pattern is segregating in a family line. Rams assigned as carriers of the putative gene did not produce carrier sons (zero of three), and this coupled with the observation that daughters of carrier rams had ovulation rates of 0. 39 (standard error of difference [SED] = 0.06) higher than contemporaries without a significant increase in the variance of log ovulation rate strongly suggests that the gene is on the X chromosome. The evidence suggests that the gene is also maternally imprinted because ovulation rate data indicate that it is expressed where females inherit a paternal allele but is silenced when inherited on a maternal allele. Maternal granddaughters of carrier rams had mean ovulation rates that were only 0.02 (SED = 0.06) higher than noncarrier ewes from the same flock. Furthermore, carrier dams expressing the gene (paternal allele) had 24 sons, none of which had female offspring that expressed the gene, whereas carrier dams not expressing the gene (maternal allele) had 7 out of 17 sons that had female progeny expressing the gene. There is no evidence of the infertility that occurs in homozygous ewes carrying the X-linked Inverdale gene. Collectively, these results suggest the existence of a novel gene for prolificacy located on the X chromosome that is maternally imprinted. The WOODLANDS: gene was only expressed upon paternal inheritance from carrier males that were the progeny of nonexpressing carrier dams. The gene was not expressed in ewes that received it from either carrier dams (expressing or nonexpressing) or from carrier males that were the progeny of expressing carrier dams. 相似文献
160.
To characterize protein phosphorylation in developing seed, a large-scale, mass spectrometry-based phosphoproteomic study was performed on whole seeds at five sequential stages of development in soybean (Glycine max), rapeseed (Brassica napus), and Arabidopsis (Arabidopsis thaliana). Phosphopeptides were enriched from 0.5 mg of total peptides using a combined strategy of immobilized metal affinity and metal oxide affinity chromatography. Enriched phosphopeptides were analyzed by Orbitrap tandem mass spectrometry and mass spectra mined against cognate genome or cDNA databases in both forward and randomized orientations, the latter to calculate false discovery rate. We identified a total of 2,001 phosphopeptides containing 1,026 unambiguous phosphorylation sites from 956 proteins, with an average false discovery rate of 0.78% for the entire study. The entire data set was uploaded into the Plant Protein Phosphorylation Database (www.p3db.org), including all meta-data and annotated spectra. The Plant Protein Phosphorylation Database is a portal for all plant phosphorylation data and allows for homology-based querying of experimentally determined phosphosites. Comparisons with other large-scale phosphoproteomic studies determined that 652 of the phosphoproteins are novel to this study. The unique proteins fall into several Gene Ontology categories, some of which are overrepresented in our study as well as other large-scale phosphoproteomic studies, including metabolic process and RNA binding; other categories are only overrepresented in our study, like embryonic development. This investigation shows the importance of analyzing multiple plants and plant organs to comprehensively map the complete plant phosphoproteome. 相似文献