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Adaptation through horizontal gene transfer in the cryptoendolithic red alga Galdieria phlegrea
Qiu, H.,Price, D.C.,Weber, A.P.M.,Reeb, V.,Chan Yang, E.,Lee, J.M.,Kim, S.Y.,Yoon, H.S.,Bhattacharya, D. Current Biology Ltd ; Elsevier Science Ltd 2013 Current biology Vol.23 No.19
Thriving in the hot, acidic, and metal-rich environments associated with geothermal areas is possible for only a few eukaryotes, with the Cyanidiophytina red algae (Cyanidium, Galdieria, and Cyanidioschyzon) being a famous example. These unicellular taxa can live in pH 0-4 and temperatures reaching up to 56<SUP>o</SUP>C [1,2]. Because Cyanidiophytina is sister to a vast array of mesophilic red algae (the Rhodophytina), such as the unicellular Porphyridium and the seaweed Chondrus[3], the genetic basis of their adaptation to extreme environments is of great interest from both the perspective of biotechnology and of evolution. The recently completed 13.7 Mbp genome sequence from the hot-spring dwelling Galdieria sulphuraria demonstrated that horizontal gene transfer (HGT) from prokaryotic sources provided this taxon with remarkable metabolic versatility (e.g., glycerol metabolism) and the ability to survive in its hostile environment (e.g., genes to detoxify mercury and arsenic) [4]. To explore the role of HGT in other members of this genus, we generated an 11.4 Mbp draft genome assembly from the sister taxon G. phlegrea DBV 009 [5]. In contrast to G. sulphuraria, this species is adapted to dry habitats near fumaroles such as fissures between rocks or cryptoendolithic environments [5,6]. Here, we provide evidence for extensive gene loss in the common ancestor of Cyanidiophytina that includes the eukaryote-derived loci required for urea utilization. Surprisingly, we find that G. phlegrea has regained the complete set of genes required for urea hydrolysis through HGT from eubacteria. The unlinked nature of these genes is likely explained by multiple gene transfers that resulted in assembly of the pathway in G. phlegrea. Our study demonstrates that genome reduction, a common outcome in eukaryotes for adaptation to a specialized niche, can be ameliorated by the gain of once lost, or novel functions through HGT.
Determination of the Fe magnetic anisotropies and the CoO frozen spins in epitaxial CoO/Fe/Ag(001)
Li, J.,Meng, Y.,Park, J. S.,Jenkins, C. A.,Arenholz, E.,Scholl, A.,Tan, A.,Son, H.,Zhao, H. W.,Hwang, Chanyong,Wu, Y. Z.,Qiu, Z. Q. American Physical Society 2011 Physical review. B, Condensed matter and materials Vol.84 No.9
A study on the dynamic characteristics of the secondary loop in nuclear power plant
Zhang, J.,Yin, S.S.,Chen, L.,Ma, Y.C.,Wang, M.J.,Fu, H.,Wu, Y.W.,Tian, W.X.,Qiu, S.Z.,Su, G.H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5
To obtain the dynamic characteristics of reactor secondary circuit under transient conditions, the system analysis program was developed in this study, where dynamic models of secondary circuit were established. The heat transfer process and the mechanical energy transfer process are modularized. Models of main equipment were built, including main turbine, condenser, steam pipe and feedwater system. The established models were verified by design value. The simulation of the secondary circuit system was conducted based on the verified models. The system response and characteristics were investigated based on the parameter transients under emergency shutdown and overload. Various operating conditions like turbine emergency shutdown and overspeed, condenser high water level, ejector failures were studied. The secondary circuit system ensures sufficient design margin to withstand the pressure and flow fluctuations. The adjustment of exhaust valve group could maintain the system pressure within a safe range, at the expense of steam quality. The condenser could rapidly take out most heat to avoid overpressure.
Ying, J,Poon, F F,Yu, J,Geng, H,Wong, A H Y,Qiu, G-H,Goh, H K,Rha, S Y,Tian, L,Chan, A T C,Sung, J J Y,Tao, Q Nature Publishing Group 2009 The British journal of cancer Vol.100 No.4
<P>Promoter CpG methylation of tumour suppressor genes (TSGs) is an epigenetic biomarker for TSG identification and molecular diagnosis. We screened genome wide for novel methylated genes through methylation subtraction of a genetic demethylation model of colon cancer (double knockout of <I>DNMT1</I> and <I>DNMT3B</I> in HCT116) and identified <I>DLEC1</I> (Deleted in lung and oesophageal cancer 1), a major 3p22.3 TSG, as one of the methylated targets. We further found that <I>DLEC1</I> was downregulated or silenced in most colorectal and gastric cell lines due to promoter methylation, whereas broadly expressed in normal tissues including colon and stomach, and unmethylated in expressing cell lines and immortalised normal colon epithelial cells. <I>DLEC1</I> expression was reactivated through pharmacologic or genetic demethylation, indicating a DNMT1/DNMT3B-mediated methylation silencing. Aberrant methylation was further detected in primary colorectal (10 out of 34, 29%) and gastric tumours (30 out of 89, 34%), but seldom in paired normal colon (0 out of 17) and gastric (1 out of 20, 5%) samples. No correlation between <I>DLEC1</I> methylation and clinical parameters of gastric cancers was found. Ectopic expression of <I>DLEC1</I> in silenced HCT116 and MKN45 cells strongly inhibited their clonogenicity. Thus, <I>DLEC1</I> is a functional tumour suppressor, being frequently silenced by epigenetic mechanism in gastrointestinal tumours.</P>
Zhang, J.,Yang, Z.,Qiu, J.,Lee, H. W. Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.16
<P>Nitrogen (N) and sulfur (S) co-doped porous carbonmaterials (NSPCs) have been prepared by the two-dimensional interlayer confinement effect of a layered double hydroxide (LDH). The NSPCs fabricated by this method have a large specific surface area of 1493.2 m(2) g(-1) and contain plenty of micropores and mesopores, which arise from either the carbonization of organic polymers and the catalytic effect of iron in LDH layers in the calcination process, or the elimination of metal oxides produced by the LDH hosts in acid dissolution. The prepared material exhibits an excellent reversible specific capacity of 1175 mA h g(-1) at 0.5C after 120 cycles. High specific discharge capacities are maintained at fast C rates, e.g. 765, 600, 510, 419, 398, 360, and 326 mA h g(-1) at 1, 2, 6, 15, 20, 30 and 60C, with 15 cycles at each step. We found that the improved electrochemical performance is due to the large quantity of edge defects, and the micropores and mesopores in the material which can provide extra Li storage regions.</P>