2,475 research outputs found
Biosynthesis of Diterpenoids in Tripterygium Adventitious Root Cultures
Adventitious root cultures were developed from Tripterygium regelii Sprague & Takeda and growth conditions optimized for the abundant production of diterpenoids, which can be collected directly from the medium. An analysis of publicly available transcriptome data sets collected with T. regelii roots and root cultures indicated the presence of a large gene family (with 20 members) for terpene synthases (TPSs). Nine candidate diterpene synthase genes were selected for follow-up functional evaluation, of which two belonged to the TPS-c, three to the TPS-e/f and four to the TPS-b subfamily. These genes were characterized by heterologous expression in a modular metabolic engineering system in E. coli. Members of the TPS-c subfamily were characterized as copalyl diphosphate (diterpene) synthases and those belonging to the TPS-e/f family catalyzed the formation of precursors of kaurane diterpenoids. The TPS-b subfamily encompassed genes coding for enzymes involved in abietane diterpenoid biosynthesis and others with activities as monoterpene synthases. The structural characterization of diterpenoids accumulating in the medium of T. regelii adventitious root cultures, facilitated by searching the Spektraris online spectral database, enabled us to formulate a biosynthetic pathway for the biosynthesis of triptolide, a diterpenoid with pharmaceutical potential. Considering the significant enrichment of diterpenoids in the culture medium, fast-growing adventitious root cultures may hold promise as a sustainable resource for the large-scale production of triptolide
Crop wild relatives as germplasm resource for cultivar improvement in mint (Mentha L.)
Mentha is a strongly scented herb of the Lamiaceae (formerly Labiatae) and includes about 30 species and hybrid species that are distributed or introduced throughout the globe. These fragrant plants have been selected throughout millennia for use by humans as herbs, spices, and pharmaceutical needs. The distilling of essential oils from mint began in Japan and England but has become a significant industrial product for the US, China, India, and other countries. The US Department of Agriculture (USDA), Agricultural Research Service, National Clonal Germplasm Repository (NCGR) maintains a mint genebank in Corvallis, Oregon. This facility preserves and distributes about 450 clones representing 34 taxa, hybrid species, advanced breeder selections, and F1 hybrids. Mint crop wild relatives are included in this unique resource. The majority of mint accessions and hybrids in this collection were initially donated in the 1970s by the A.M. Todd Company, located in Kalamazoo, Michigan. Other representatives of diverse mint taxa and crop wild relatives have since been obtained from collaborators in Australia, New Zealand, Europe, and Vietnam. These mints have been evaluated for cytology, oil components, verticillium wilt resistance, and key morphological characters. Pressed voucher specimens have been prepared for morphological identity verification. An initial set of microsatellite markers has been developed to determine clonal identity and assess genetic diversity. Plant breeders at private and public institutions are using molecular analysis to determine identity and diversity of the USDA mint collection. Evaluation and characterization includes essential oil content, disease resistance, male sterility, and other traits for potential breeding use. These accessions can be a source for parental genes for enhancement efforts to produce hybrids, or for breeding new cultivars for agricultural production. Propagules of Mentha are available for distribution to international researchers as stem cuttings, rhizome cuttings, or seed, which can be requested through the GRIN-Global database of the US National Plant Germplasm System, subject to international treaty and quarantine regulations
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Study of the impact of ice formation in leads upon the sea ice pack mass balance using a new frazil and grease ice parameterization
Leads are cracks in sea ice that often form because of deformation. During winter months, leads expose the ocean to the cold atmosphere, resulting in supercooling and the formation of frazil ice crystals within the mixed layer. Here the authors investigate the role of frazil ice formation in leads on the mass balance of the sea ice pack through the incorporation of a new module into the Los Alamos sea ice model (CICE). The frazil ice module considers an initial cooling of leads followed by a steady-state formation of uniformly distributed single size frazil ice crystals that precipitate to the ocean surface as grease ice. The grease ice is pushed against one of the lead edges by wind and water drag that the authors represent through a variable collection thickness for new sea ice. Simulations of the sea ice cover in the Arctic and Antarctic are performed and compared to a model that treats leads the same as the open ocean. The processes of ice formation in the new module slow down the refreezing of leads, resulting in a longer period of frazil ice production. The fraction of frazil-derived sea ice increases from 10% to 50%, corresponding better to observations. The new module has higher ice formation rates in areas of high ice concentration and thus has a greater impact within multiyear ice than it does in the marginal seas. The thickness of sea ice in the central Arctic increases by over 0.5 m, whereas within the Antarctic it remains unchanged
Metabolomics as a Hypothesis-Generating Functional Genomics Tool for the Annotation of Arabidopsis thaliana Genes of “Unknown Function”
Metabolomics is the methodology that identifies and measures global pools of small molecules (of less than about 1,000 Da) of a biological sample, which are collectively called the metabolome. Metabolomics can therefore reveal the metabolic outcome of a genetic or environmental perturbation of a metabolic regulatory network, and thus provide insights into the structure and regulation of that network. Because of the chemical complexity of the metabolome and limitations associated with individual analytical platforms for determining the metabolome, it is currently difficult to capture the complete metabolome of an organism or tissue, which is in contrast to genomics and transcriptomics. This paper describes the analysis of Arabidopsis metabolomics data sets acquired by a consortium that includes five analytical laboratories, bioinformaticists, and biostatisticians, which aims to develop and validate metabolomics as a hypothesis-generating functional genomics tool. The consortium is determining the metabolomes of Arabidopsis T-DNA mutant stocks, grown in standardized controlled environment optimized to minimize environmental impacts on the metabolomes. Metabolomics data were generated with seven analytical platforms, and the combined data is being provided to the research community to formulate initial hypotheses about genes of unknown function (GUFs). A public database (www.PlantMetabolomics.org) has been developed to provide the scientific community with access to the data along with tools to allow for its interactive analysis. Exemplary datasets are discussed to validate the approach, which illustrate how initial hypotheses can be generated from the consortium-produced metabolomics data, integrated with prior knowledge to provide a testable hypothesis concerning the functionality of GUFs
Metabolomics : population epidemiology and concordance in Australian children aged 11-12 years and their parents
Objectives Nuclear magnetic resonance (NMR) metabolomics is high throughput and cost-effective, with the potential to improve the understanding of disease and risk. We examine the circulating metabolic profile by quantitative NMR metabolomics of a sample of Australian 11-12 year olds children and their parents, describe differences by age and sex, and explore the correlation of metabolites in parent-child dyads. Design The population-based cross-sectional Child Health CheckPoint study nested within the Longitudinal Study of Australian Children. Setting Blood samples collected from CheckPoint participants at assessment centres in seven Australian cities and eight regional towns; February 2015-March 2016. Participants 1180 children and 1325 parents provided a blood sample and had metabolomics data available. This included 1133 parent-child dyads (518 mother-daughter, 469 mother-son, 68 father-daughter and 78 father-son). Outcome measures 228 metabolic measures were obtained for each participant. We focused on 74 biomarkers including amino acid species, lipoprotein subclass measures, lipids, fatty acids, measures related to fatty acid saturation, and composite markers of inflammation and energy homeostasis. Results We identified differences in the concentration of specific metabolites between childhood and adulthood and in metabolic profiles in children and adults by sex. In general, metabolite concentrations were higher in adults than children and sex differences were larger in adults than in children. Positive correlations were observed for the majority of metabolites including isoleucine (CC 0.33, 95% CI 0.27 to 0.38), total cholesterol (CC 0.30, 95% CI 0.24 to 0.35) and omega 6 fatty acids (CC 0.28, 95% CI 0.23 to 0.34) in parent-child comparisons. Conclusions We describe the serum metabolite profiles from mid-childhood and adulthood in a population-based sample, together with a parent-child concordance. Differences in profiles by age and sex were observed. These data will be informative for investigation of the childhood origins of adult non-communicable diseases and for comparative studies in other populations.Peer reviewe
Early detection of duodenal cancer by upper gastrointestinal-endoscopy in Lynch syndrome
Small bowel cancer (SBC) is the malignancy with the highest standardized incidence ratio in Lynch syndrome (LS) patients. Of all SBCs, about 50% are duodenal cancers (DCs), therefore being accessible by esophago-gastro-duodenoscopy (EGD) for surveillance. We asked whether early detection of DC is possible for LS patients undergoing surveillance by EGD and if surveillance should be limited to specific subgroups. Data for LS patients with DC were retrieved from the registry of the German Consortium for Familial Intestinal Cancer. Patients undergoing active surveillance by EGDs (surveillance group) were compared to those who did not (nonsurveillance group) regarding tumor stage at diagnosis. Union for International Cancer Control stages I-IIA were defined as early stage disease and IIB-IV as advanced stage disease. Statistical analysis was performed using Fisher's exact test. Among 2015 patients with pathogenic variants in any mismatch-repair-gene, 47 patients with 49 DCs were identified. In 10% of cases, patients were under 35 years at diagnosis; family and personal tumor history did not correlate with DC diagnosis. Pathogenic germline variants in MSH6, PMS2 or EPCAM were present in 10% of patients. Statistical analysis could be performed on 13 DC patients in the surveillance group and 14 in the nonsurveillance group. Early detection was possible for 71% of patients in the surveillance group and 29% of patients in the nonsurveillance group (P = .021). Early detection of DC by EGD in LS patients is feasible regardless of family history, mutational status and should start no later than 25 years of age
Adenoma and colorectal cancer risks in Lynch syndrome, Lynch-like syndrome and familial colorectal cancer type X
Lynch syndrome (LS), Lynch-like syndrome (LLS) and familial colorectal cancer type X (FCCX) are different entities of familial cancer predisposition leading to an increased risk of colorectal cancer (CRC). The aim of this prospective study was to characterise and to compare the risks for adenoma and CRC in these three risk groups. Data was taken from the registry of the German Consortium for Familial Intestinal Cancer. Patients were prospectively followed up in an intensified colonoscopic surveillance programme that included annual examinations. Cumulative risks for adenoma and CRC were calculated separately for LS, LLS and FCCX, and then for males and females. Multivariate Cox regression was used to analyse the independent contributions of risk group, mismatch repair gene (within LS), sex and previous adenoma. The study population comprised 1448 individuals (103 FCCX, 481 LLS and 864 LS). The risks were similar for colorectal adenomas, but different for first and metachronous CRC between the three risk groups. CRC risk was highest in LS, followed by LLS and lowest in FCCX. Male sex and a prevalent adenoma in the index colonoscopy were associated with a higher risk for incident adenoma and CRC. In patients with LS, CRC risks were particularly higher in female MSH2 than MLH1 carriers. Our study may support the development of risk-adapted surveillance policies in LS, LLS and FCCX.
What's new?
While associations between colorectal cancer (CRC) risk and Lynch syndrome (LS) are well-described, less is known about CRC risks linked to the closely related Lynch-like syndrome (LLS) and familial colorectal cancer type X (FCCX). In this prospective follow-up study of patients with LS, LLS, and FCCX, risks were similar for colorectal adenomas but considerably different for first and metachronous CRCs. In addition, LS females who carried MSH2 mutations had notably higher CRC risks than female MLH1 mutation carriers. The identification of variations in carcinogenic pathways between LS, LLS, and FCCX could enable risk-adapted CRC surveillance for these syndromes
Value of upper gastrointestinal endoscopy for gastric cancer surveillance in patients with Lynch syndrome
In our study, we evaluated the effectiveness of upper gastrointestinal (GI) endoscopy as an instrument for early gastric cancer (GC) detection in Lynch syndrome (LS) patients by analyzing data from the registry of the German Consortium for Familial Intestinal Cancer. In a prospective, multicenter cohort study, 1128 out of 2009 registered individuals with confirmed LS underwent 5176 upper GI endoscopies. Compliance was good since 77.6% of upper GI endoscopies were completed within the recommended interval of 1 to 3 years. Forty-nine GC events were observed in 47 patients. MLH1 (n = 21) and MSH2 (n = 24) mutations were the most prevalent. GCs in patients undergoing regular surveillance were diagnosed significantly more often in an early-stage disease (UICC I) than GCs detected through symptoms (83% vs 25%; P = .0231). Thirty-two (68%) patients had a negative family history of GC. The median age at diagnosis was 51 years (range 28-66). Of all GC patients, 13 were diagnosed at an age younger than 45. Our study supports the recommendation of regular upper GI endoscopy surveillance for LS patients beginning no later than at the age of 30.
What's new?
Risk of gastric cancer (GC) is significantly increased among patients with Lynch syndrome (LS). GC screening in LS patients, however, is fraught with uncertainty, particularly regarding the use of esophagogastroduodenoscopy (EGD). The authors of this study investigated the use of EGD for regular GC surveillance in a German cohort of LS patients. Regular surveillance by EGD resulted in more frequent diagnosis and significant down-staging of GC, relative to detection via symptoms alone. In most cases, family history of GC was negative. This study supports recommendations for regular gastroscopic surveillance in LS patients starting by age 30
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Biological, clinical and population relevance of 95 loci for blood lipids.
Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P < 5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD
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