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971.
The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle 总被引:1,自引:0,他引:1
Suen G Teiling C Li L Holt C Abouheif E Bornberg-Bauer E Bouffard P Caldera EJ Cash E Cavanaugh A Denas O Elhaik E Favé MJ Gadau J Gibson JD Graur D Grubbs KJ Hagen DE Harkins TT Helmkampf M Hu H Johnson BR Kim J Marsh SE Moeller JA Muñoz-Torres MC Murphy MC Naughton MC Nigam S Overson R Rajakumar R Reese JT Scott JJ Smith CR Tao S Tsutsui ND Viljakainen L Wissler L Yandell MD Zimmer F Taylor J Slater SC Clifton SW Warren WC Elsik CG Smith CD Weinstock GM Gerardo NM Currie CR 《PLoS genetics》2011,7(2):e1002007
Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses. 相似文献
972.
The ability to respond to environmental temperature variation is essential for survival in animals. Flies show robust temperature-preference behaviour (TPB) to find optimal temperatures. Recently, we have shown that Drosophila mushroom body (MB) functions as a center controlling TPB. However, neuromodulators that control the TPB in MB remain unknown. To identify the functions of dopamine in TPB, we have conducted various genetic studies in Drosophila. Inhibition of dopamine biosynthesis by genetic mutations or treatment with chemical inhibitors caused flies to prefer temperatures colder than normal. We also found that dopaminergic neurons are involved in TPB regulation, as the targeted inactivation of dopaminergic neurons by expression of a potassium channel (Kir2.1) induced flies with the loss of cold avoidance. Consistently, the mutant flies for dopamine receptor gene (DopR) also showed a cold temperature preference, which was rescued by MB-specific expression of DopR. Based on these results, we concluded that dopamine in MB is a key component in the homeostatic temperature control of Drosophila. The current findings will provide important bases to understand the logic of thermosensation and temperature preference decision in Drosophila. 相似文献
973.
Nalls MA Couper DJ Tanaka T van Rooij FJ Chen MH Smith AV Toniolo D Zakai NA Yang Q Greinacher A Wood AR Garcia M Gasparini P Liu Y Lumley T Folsom AR Reiner AP Gieger C Lagou V Felix JF Völzke H Gouskova NA Biffi A Döring A Völker U Chong S Wiggins KL Rendon A Dehghan A Moore M Taylor K Wilson JG Lettre G Hofman A Bis JC Pirastu N Fox CS Meisinger C Sambrook J Arepalli S Nauck M Prokisch H Stephens J Glazer NL Cupples LA Okada Y Takahashi A Kamatani Y Matsuda K Tsunoda T Tanaka T Kubo M 《PLoS genetics》2011,7(6):e1002113
White blood cell (WBC) count is a common clinical measure from complete blood count assays, and it varies widely among healthy individuals. Total WBC count and its constituent subtypes have been shown to be moderately heritable, with the heritability estimates varying across cell types. We studied 19,509 subjects from seven cohorts in a discovery analysis, and 11,823 subjects from ten cohorts for replication analyses, to determine genetic factors influencing variability within the normal hematological range for total WBC count and five WBC subtype measures. Cohort specific data was supplied by the CHARGE, HeamGen, and INGI consortia, as well as independent collaborative studies. We identified and replicated ten associations with total WBC count and five WBC subtypes at seven different genomic loci (total WBC count-6p21 in the HLA region, 17q21 near ORMDL3, and CSF3; neutrophil count-17q21; basophil count- 3p21 near RPN1 and C3orf27; lymphocyte count-6p21, 19p13 at EPS15L1; monocyte count-2q31 at ITGA4, 3q21, 8q24 an intergenic region, 9q31 near EDG2), including three previously reported associations and seven novel associations. To investigate functional relationships among variants contributing to variability in the six WBC traits, we utilized gene expression- and pathways-based analyses. We implemented gene-clustering algorithms to evaluate functional connectivity among implicated loci and showed functional relationships across cell types. Gene expression data from whole blood was utilized to show that significant biological consequences can be extracted from our genome-wide analyses, with effect estimates for significant loci from the meta-analyses being highly corellated with the proximal gene expression. In addition, collaborative efforts between the groups contributing to this study and related studies conducted by the COGENT and RIKEN groups allowed for the examination of effect homogeneity for genome-wide significant associations across populations of diverse ancestral backgrounds. 相似文献
974.
Myostatin (MSTN) is a potent negative regulator of skeletal muscle growth in mammalian species, and its activity is inhibited
by MSTN prodomain, the N-terminal part of proMSTN cleaved during post-translational MSTN processing. In fish, MSTN also appears
to suppress fish muscle growth with its activity being inhibited by prodomain. The objective of this study was to produce
bioactive MSTN-1 prodomain of rockfish (S. schlegeli), a commercial aquaculture species in East Asia, in E. coli using maltose binding protein (MBP) as a fusion partner. Rockfish MSTN-1 prodomain (sMSTN1pro) cDNA was cloned into the pMALc2x
vector, and proteins (MBP-sMSTN1pro) were expressed in Rosetta-gami 2(DE3)pLysS cells by IPTG induction. The MBP-sMSTN1pro
was expressed in soluble forms, and affinity purified using amylose resin. The affinity purified MBP-sMSTN1pro suppressed
MSTN activity in vitro. The results suggest that MBP is probably a useful fusion partner in producing bioactive MSTN prodomains
of various animal species in E. coli. 相似文献
975.
976.
Levy MZ Small DS Vilhena DA Bowman NM Kawai V Cornejo del Carpio JG Cordova-Benzaquen E Gilman RH Bern C Plotkin JB 《PLoS computational biology》2011,7(9):e1002146
Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al espa?ol disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1. 相似文献
977.
Lee KJ Jeong CS An YJ Lee HJ Park SJ Seok YJ Kim P Lee JH Lee KH Cha SS 《Nature chemical biology》2011,7(7):434-436
The interaction between fermentation-respiration switch (FrsA) protein and glucose-specific enzyme IIA(Glc) increases glucose fermentation under oxygen-limited conditions. We show that FrsA converts pyruvate to acetaldehyde and carbon dioxide in a cofactor-independent manner and that its pyruvate decarboxylation activity is enhanced by the dephosphorylated form of IIA(Glc) (d-IIA(Glc)). Crystal structures of FrsA and its complex with d-IIA(Glc) revealed residues required for catalysis as well as the structural basis for the activation by d-IIA(Glc). 相似文献
978.
One approach to super-resolution fluorescence imaging uses sequential activation and localization of individual fluorophores to achieve high spatial resolution. Essential to this technique is the choice of fluorescent probes; the properties of the probes, including photons per switching event, on-off duty cycle, photostability and number of switching cycles, largely dictate the quality of super-resolution images. Although many probes have been reported, a systematic characterization of the properties of these probes and their impact on super-resolution image quality has been described in only a few cases. Here we quantitatively characterized the switching properties of 26 organic dyes and directly related these properties to the quality of super-resolution images. This analysis provides guidelines for characterization of super-resolution probes and a resource for selecting probes based on performance. Our evaluation identified several photoswitchable dyes with good to excellent performance in four independent spectral ranges, with which we demonstrated low-cross-talk, four-color super-resolution imaging. 相似文献
979.
Lee K Kim H Kim JM Kim JR Kim KJ Kim YJ Park SI Jeong JH Moon YM Lim HS Bae DW Kwon J Ko CY Kim HS Shin HI Jeong D 《Journal of cellular and molecular medicine》2011,15(10):2082-2094
Systemic transplantation of adipose-derived stem cells (ASCs) is emerging as a novel therapeutic option for functional recovery of diverse damaged tissues. This study investigated the effects of systemic transplantation of human ASCs (hASCs) on bone repair. We found that hASCs secrete various bone cell-activating factors, including hepatocyte growth factor and extracellular matrix proteins. Systemic transplantation of hASCs into ovariectomized mice induced an increased number of both osteoblasts and osteoclasts in bone tissue and thereby prevented bone loss. We also observed that conditioned medium from hASCs is capable of stimulating proliferation and differentiation of osteoblasts via Smad/extracellular signal-regulated kinase (ERK)/JNK (c-jun NH(2) -terminal kinase) activation as well as survival and differentiation of osteoclasts via ERK/JNK/p38 activation in vitro. Overall, our findings suggest that paracrine factors secreted from hASCs improve bone repair and that hASCs can be a valuable tool for use in osteoporosis therapy. 相似文献
980.
Miriam Kunze Sangsik Jeong Elie Paillard Monika Schönhoff Martin Winter Stefano Passerini 《Liver Transplantation》2011,1(2):274-281
Some cations of ionic liquids (ILs) of interest for high‐energy electrochemical storage devices, such as lithium batteries and supercapacitors, have a structure similar to that of surfactants. For such, it is very important to understand if these IL cations tend to aggregate like surfactants since this would affect the ion mobility and thus the ionic conductivity. The aggregation behaviour of ILs consisting of the bis(trifluoromethanesulfonyl)imide anion and different N‐alkyl‐N‐methyl‐pyrrolidinium cations, with the alkyl chain varied from C3H7 to C8H17, was extensively studied with NMR and Raman methods, also in the presence of Li+ cations. 2H NMR spin‐lattice and spin‐spin relaxation rates were analyzed by applying the “two step” model of surfactant dynamics. Here we show that, indeed, the cations in these ILs tend to form aggregates surrounded by the anions. The effect is even more pronounced in the presence of dissolved lithium cations. 相似文献