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1.
Metagenomic and functional analysis of hindgut microbiota of a wood-feeding higher termite 总被引:6,自引:0,他引:6
Warnecke F Luginbühl P Ivanova N Ghassemian M Richardson TH Stege JT Cayouette M McHardy AC Djordjevic G Aboushadi N Sorek R Tringe SG Podar M Martin HG Kunin V Dalevi D Madejska J Kirton E Platt D Szeto E Salamov A Barry K Mikhailova N Kyrpides NC Matson EG Ottesen EA Zhang X Hernández M Murillo C Acosta LG Rigoutsos I Tamayo G Green BD Chang C Rubin EM Mathur EJ Robertson DE Hugenholtz P Leadbetter JR 《Nature》2007,450(7169):560-565
From the standpoints of both basic research and biotechnology, there is considerable interest in reaching a clearer understanding of the diversity of biological mechanisms employed during lignocellulose degradation. Globally, termites are an extremely successful group of wood-degrading organisms and are therefore important both for their roles in carbon turnover in the environment and as potential sources of biochemical catalysts for efforts aimed at converting wood into biofuels. Only recently have data supported any direct role for the symbiotic bacteria in the gut of the termite in cellulose and xylan hydrolysis. Here we use a metagenomic analysis of the bacterial community resident in the hindgut paunch of a wood-feeding 'higher' Nasutitermes species (which do not contain cellulose-fermenting protozoa) to show the presence of a large, diverse set of bacterial genes for cellulose and xylan hydrolysis. Many of these genes were expressed in vivo or had cellulase activity in vitro, and further analyses implicate spirochete and fibrobacter species in gut lignocellulose degradation. New insights into other important symbiotic functions including H2 metabolism, CO2-reductive acetogenesis and N2 fixation are also provided by this first system-wide gene analysis of a microbial community specialized towards plant lignocellulose degradation. Our results underscore how complex even a 1-microl environment can be. 相似文献
2.
Lord C Bhandari D Menon S Ghassemian M Nycz D Hay J Ghosh P Ferro-Novick S 《Nature》2011,473(7346):181-186
How the directionality of vesicle traffic is achieved remains an important unanswered question in cell biology. The Sec23p/Sec24p coat complex sorts the fusion machinery (SNAREs) into vesicles as they bud from the endoplasmic reticulum (ER). Vesicle tethering to the Golgi begins when the tethering factor TRAPPI binds to Sec23p. Where the coat is released and how this event relates to membrane fusion is unknown. Here we use a yeast transport assay to demonstrate that an ER-derived vesicle retains its coat until it reaches the Golgi. A Golgi-associated kinase, Hrr25p (CK1δ orthologue), then phosphorylates the Sec23p/Sec24p complex. Coat phosphorylation and dephosphorylation are needed for vesicle fusion and budding, respectively. Additionally, we show that Sec23p interacts in a sequential manner with different binding partners, including TRAPPI and Hrr25p, to ensure the directionality of ER-Golgi traffic and prevent the back-fusion of a COPII vesicle with the ER. These events are conserved in mammalian cells. 相似文献
3.
Zody MC Garber M Sharpe T Young SK Rowen L O'Neill K Whittaker CA Kamal M Chang JL Cuomo CA Dewar K FitzGerald MG Kodira CD Madan A Qin S Yang X Abbasi N Abouelleil A Arachchi HM Baradarani L Birditt B Bloom S Bloom T Borowsky ML Burke J Butler J Cook A DeArellano K DeCaprio D Dorris L Dors M Eichler EE Engels R Fahey J Fleetwood P Friedman C Gearin G Hall JL Hensley G Johnson E Jones C Kamat A Kaur A Locke DP Madan A Munson G Jaffe DB Lui A Macdonald P Mauceli E Naylor JW Nesbitt R Nicol R 《Nature》2006,440(7084):671-675
Here we present a finished sequence of human chromosome 15, together with a high-quality gene catalogue. As chromosome 15 is one of seven human chromosomes with a high rate of segmental duplication, we have carried out a detailed analysis of the duplication structure of the chromosome. Segmental duplications in chromosome 15 are largely clustered in two regions, on proximal and distal 15q; the proximal region is notable because recombination among the segmental duplications can result in deletions causing Prader-Willi and Angelman syndromes. Sequence analysis shows that the proximal and distal regions of 15q share extensive ancient similarity. Using a simple approach, we have been able to reconstruct many of the events by which the current duplication structure arose. We find that most of the intrachromosomal duplications seem to share a common ancestry. Finally, we demonstrate that some remaining gaps in the genome sequence are probably due to structural polymorphisms between haplotypes; this may explain a significant fraction of the gaps remaining in the human genome. 相似文献
4.
A better understanding of solid-liquid separation would assist in improving the thickening performance and perhaps water recovery as well. The present work aimed to develop an empirical model to study the effects of ore properties on the thickening process based on pilot tests using a column. A hydro-cyclone was used to prepare the required samples for the experiments. The model significantly predicted the experimental underflow solid content using a regression equation at a given solid flux and bed level for different samples, indicating that ore properties are the effective parameters in the thickening process. This work confirmed that the water recovery would be increased about 5% by separating the feed into two parts, overflow and underflow, and introducing two different thickeners into them separately. This is duo to the fact that thickeners are limited by permeability and compressibility in operating conditions. 相似文献
5.
Ellinghaus E Ellinghaus D Stuart PE Nair RP Debrus S Raelson JV Belouchi M Fournier H Reinhard C Ding J Li Y Tejasvi T Gudjonsson J Stoll SW Voorhees JJ Lambert S Weidinger S Eberlein B Kunz M Rahman P Gladman DD Gieger C Wichmann HE Karlsen TH Mayr G Albrecht M Kabelitz D Mrowietz U Abecasis GR Elder JT Schreiber S Weichenthal M Franke A 《Nature genetics》2010,42(11):991-995
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Najmabadi H Hu H Garshasbi M Zemojtel T Abedini SS Chen W Hosseini M Behjati F Haas S Jamali P Zecha A Mohseni M Püttmann L Vahid LN Jensen C Moheb LA Bienek M Larti F Mueller I Weissmann R Darvish H Wrogemann K Hadavi V Lipkowitz B Esmaeeli-Nieh S Wieczorek D Kariminejad R Firouzabadi SG Cohen M Fattahi Z Rost I Mojahedi F Hertzberg C Dehghan A Rajab A Banavandi MJ Hoffer J Falah M Musante L Kalscheuer V Ullmann R Kuss AW Tzschach A Kahrizi K Ropers HH 《Nature》2011,478(7367):57-63
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Specifications of inclusions such as the type, morphology, number, composition, size, and place of inclusions in HK40 heat-resistant casting steel were studied by optical microscopy and scanning electron microscopy equipped with an energy-dispersive spectroscopy system. The effects of calcium silicide (CaSi) addition on these characteristics were evaluated at two pouring temperatures of 1420℃ and 1470℃. It was found that most of the appeared inclusions were in the type of chromium oxide. CaSi addition had a significant effect on the morphological modification, size and distribution of inclusions as well as changing the composition to oxide-sulfide compounds. 相似文献
9.
This paper proposes a selfsimilar local neurofuzzy (SSLNF) model with mutual informati onbased input selection algorithm for the shortterm electricity demand forecasting. The proposed self similar model is composed of a number of local models, each being a local linear neurofuzzy (LLNF) model, and their associated validity functions and can be interpreted itself as an LLNF model. The proposed model is trained by a nested local liner model tree (NLOLIMOT) learning algorithm which partitions the input space into axisorthogonal subdomains and then fits an LLNF model and its associated validity function on each subdomain. Furthermore, the proposed approach allows different input spaces for rule premises (validity functions) and consequents (local models). This appealing property is employed to assign the candidate input variables (i.e., previous load and temperature) which influence shortterm electricity demand in linear and nonlinear ways to local models and validity functions, respectively. Numerical results from shortterm load forecasting in the New England in 2002 demonstrated the accuracy of the SSLNF model for the STLF applications. 相似文献