We report the complete genome sequence of Zymomonas mobilis ZM4 (ATCC31821), an ethanologenic microorganism of interest for the production of fuel ethanol. The genome consists of 2,056,416 base pairs forming a circular chromosome with 1,998 open reading frames (ORFs) and three ribosomal RNA transcription units. The genome lacks recognizable genes for 6-phosphofructokinase, an essential enzyme in the Embden-Meyerhof-Parnas pathway, and for two enzymes in the tricarboxylic acid cycle, the 2-oxoglutarate dehydrogenase complex and malate dehydrogenase, so glucose can be metabolized only by the Entner-Doudoroff pathway. Whole genome microarrays were used for genomic comparisons with the Z. mobilis type strain ZM1 (ATCC10988) revealing that 54 ORFs predicted to encode for transport and secretory proteins, transcriptional regulators and oxidoreductase in the ZM4 strain were absent from ZM1. Most of these ORFs were also found to be actively transcribed in association with ethanol production by ZM4.Growing environmental concerns over the use and depletion of nonrenewable energy resources, together with the recent price increases and instabilities in the international oil markets have stimulated an increasing interest in the use of fermentation processes for the large-scale production of alternative fuels such as ethanol. As such, ethanol-producing microorganisms, such as the Gram-negative bacterium Z. mobilis, have potential for the production of fuel ethanol.Z. mobilis, which is used in the tropics to produce pulque and alcoholic palm wines, uses the Entner-Doudoroff (ED) pathway to metabolize glucose, which results in only 1 mole of ATP being produced per mole of glucose 1 . The potential advantages of using Z. mobilis for ethanol production include: (i) its high and specific rates of sugar uptake and ethanol production, (ii) its production of ethanol at yields close to the theoretical maximum with relatively low biomass formation, (iii) its high ethanol tolerance of up to 16% (vol/vol) and (iv) its facility for genetic manipulation 2-6 . However, wild strains of Z. mobilis can use only glucose, fructose and sucrose as carbon substrates, so recent research has focused on the development of recombinant strains capable of using pentose sugars 7,8 for the conversion of cheaper lignocellulosic hydrolysates to ethanol. Improved mutants 9-11 as well as the application of metabolic flux analysis, sitedirected mutagenesis, specific gene deletion/insertion and metabolic engineering for strain developlment 12,13 have also been reported. A physical map of Z. mobilis ZM4 genome and the ribosomal transcriptional unit have been previously reported 14,15 . In the current paper, the features of the complete sequence of the Z. mobilis ZM4 genome are presented and genomic characters are compared with those of another Z. mobilis strain, ZM1.
DNA methylation changes are associated with cigarette smoking. We used the Illumina Infinium HumanMethylation450 array to determine whether methylation in DNA from pre‐diagnostic, peripheral blood samples is associated with lung cancer risk. We used a case‐control study nested within the EPIC‐Italy cohort and a study within the MCCS cohort as discovery sets (a total of 552 case‐control pairs). We validated the top signals in 429 case‐control pairs from another 3 studies. We identified six CpGs for which hypomethylation was associated with lung cancer risk: cg05575921 in the AHRR gene (p‐valuepooled = 4 × 10−17), cg03636183 in the F2RL3 gene (p‐valuepooled = 2 × 10 − 13), cg21566642 and cg05951221 in 2q37.1 (p‐valuepooled = 7 × 10−16 and 1 × 10−11 respectively), cg06126421 in 6p21.33 (p‐valuepooled = 2 × 10−15) and cg23387569 in 12q14.1 (p‐valuepooled = 5 × 10−7). For cg05951221 and cg23387569 the strength of association was virtually identical in never and current smokers. For all these CpGs except for cg23387569, the methylation levels were different across smoking categories in controls (p‐valuesheterogeneity ≤ 1.8 x10 − 7), were lowest for current smokers and increased with time since quitting for former smokers. We observed a gain in discrimination between cases and controls measured by the area under the ROC curve of at least 8% (p‐values ≥ 0.003) in former smokers by adding methylation at the 6 CpGs into risk prediction models including smoking status and number of pack‐years. Our findings provide convincing evidence that smoking and possibly other factors lead to DNA methylation changes measurable in peripheral blood that may improve prediction of lung cancer risk.
Flowering is an important agronomic trait that determines crop yield. Soybean is a major oilseed legume crop used for human and animal feed. Legumes have unique vegetative and floral complexities. Our understanding of the molecular basis of flower initiation and development in legumes is limited. Here, we address this by using a computational approach to examine flowering regulatory genes in the soybean genome in comparison to the most studied model plant, Arabidopsis. For this comparison, a genome-wide analysis of orthologue groups was performed, followed by an in silico gene expression analysis of the identified soybean flowering genes. Phylogenetic analyses of the gene families highlighted the evolutionary relationships among these candidates. Our study identified key flowering genes in soybean and indicates that the vernalisation and the ambient-temperature pathways seem to be the most variant in soybean. A comparison of the orthologue groups containing flowering genes indicated that, on average, each Arabidopsis flowering gene has 2-3 orthologous copies in soybean. Our analysis highlighted that the CDF3, VRN1, SVP, AP3 and PIF3 genes are paralogue-rich genes in soybean. Furthermore, the genome mapping of the soybean flowering genes showed that these genes are scattered randomly across the genome. A paralogue comparison indicated that the soybean genes comprising the largest orthologue group are clustered in a 1.4 Mb region on chromosome 16 of soybean. Furthermore, a comparison with the undomesticated soybean (Glycine soja) revealed that there are hundreds of SNPs that are associated with putative soybean flowering genes and that there are structural variants that may affect the genes of the light-signalling and ambient-temperature pathways in soybean. Our study provides a framework for the soybean flowering pathway and insights into the relationship and evolution of flowering genes between a short-day soybean and the long-day plant, Arabidopsis.
Aberrant DNA methylation is a key feature of breast carcinoma. We aimed to test the association between breast cancer risk and epigenome-wide methylation in DNA from peripheral blood. Nested case-control study within the prospective Melbourne Collaborative Cohort Study. DNA was extracted from before-diagnosis blood samples (420 incident cases and matched controls). Methylation was measured with the Illumina Infinium Human Methylation 450 BeadChip array. Odds ratio (OR) for epigenome-wide methylation, quantified as the mean beta values across the CpGs, in relation to breast cancer risk were estimated using conditional logistic regression. Overall, the OR for breast cancer was 0.42 (95% CI 0.20-0.90) for the top versus bottom quartile of epigenome-wide DNA methylation and the OR for a one standard deviation increment was 0.69 (95% CI 0.50-0.95; test for linear trend, p = 0.02). Epigenome-wide DNA methylation of CpGs within functional promoters was associated with an increased risk, whereas epigenome-wide DNA methylation of genomic regions outside promoters was associated with decreased risk (test for heterogeneity, p = 0.0002). The increased risk associated with epigenome-wide DNA methylation in functional promoters did not vary by time between blood collection and diagnosis, whereas the inverse association with epigenome-wide DNA methylation outside functional promoters was strongest when the interval from blood collection to diagnosis was less than 5 years and weakest for the longest interval. Epigenome-wide methylation in DNA extracted from peripheral blood collected before diagnosis may have potential utility as markers of breast cancer risk and for early detection.
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