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991.
Mónica Costa Eugénia Cruz James C. Barton Ketil Thorstensen Sandra Morais Berta M. da Silva Jorge P. Pinto Cristina P. Vieira Jorge Vieira Ronald T. Acton Gra?a Porto 《PloS one》2013,8(11)
Hereditary Hemochromatosis (HH) is a recessively inherited disorder of iron overload occurring commonly in subjects homozygous for the C282Y mutation in HFE gene localized on chromosome 6p21.3 in linkage disequilibrium with the human leukocyte antigen (HLA)-A locus. Although its genetic homogeneity, the phenotypic expression is variable suggesting the presence of modifying factors. One such genetic factor, a SNP microhaplotype named A-A-T, was recently found to be associated with a more severe phenotype and also with low CD8+T-lymphocyte numbers. The present study aimed to test whether the predictive value of the A-A-T microhaplotype remained in other population settings. In this study of 304 HH patients from 3 geographically distant populations (Porto, Portugal 65; Alabama, USA 57; Nord-Trøndelag, Norway 182), the extended haplotypes involving A-A-T were studied in 608 chromosomes and the CD8+ T-lymphocyte numbers were determined in all subjects. Patients from Porto had a more severe phenotype than those from other settings. Patients with A-A-T seemed on average to have greater iron stores (p = 0.021), but significant differences were not confirmed in the 3 separate populations. Low CD8+ T-lymphocytes were associated with HLA-A*03-A-A-T in Porto and Alabama patients but not in the greater series from Nord-Trøndelag. Although A-A-T may signal a more severe iron phenotype, this study was unable to prove such an association in all population settings, precluding its use as a universal predictive marker of iron overload in HH. Interestingly, the association between A-A-T and CD8+ T-lymphocytes, which was confirmed in Porto and Alabama patients, was not observed in Nord-Trøndelag patients, showing that common HLA haplotypes like A*01–B*08 or A*03–B*07 segregating with HFE/C282Y in the three populations may carry different messages. These findings further strengthen the relevance of HH as a good disease model to search for novel candidate loci associated with the genetic transmission of CD8+ T-lymphocyte numbers. 相似文献
992.
Muriel Mazet Pauline Morand Marc Biran Guillaume Bouyssou Pierrette Courtois Sylvie Daulouède Yoann Millerioux Jean-Michel Franconi Philippe Vincendeau Patrick Moreau Frédéric Bringaud 《PLoS neglected tropical diseases》2013,7(12)
Background
The bloodstream forms of Trypanosoma brucei, the causative agent of sleeping sickness, rely solely on glycolysis for ATP production. It is generally accepted that pyruvate is the major end-product excreted from glucose metabolism by the proliferative long-slender bloodstream forms of the parasite, with virtually no production of succinate and acetate, the main end-products excreted from glycolysis by all the other trypanosomatid adaptative forms, including the procyclic insect form of T. brucei.Methodology/Principal Findings
A comparative NMR analysis showed that the bloodstream long-slender and procyclic trypanosomes excreted equivalent amounts of acetate and succinate from glucose metabolism. Key enzymes of acetate production from glucose-derived pyruvate and threonine are expressed in the mitochondrion of the long-slender forms, which produces 1.4-times more acetate from glucose than from threonine in the presence of an equal amount of both carbon sources. By using a combination of reverse genetics and NMR analyses, we showed that mitochondrial production of acetate is essential for the long-slender forms, since blocking of acetate biosynthesis from both carbon sources induces cell death. This was confirmed in the absence of threonine by the lethal phenotype of RNAi-mediated depletion of the pyruvate dehydrogenase, which is involved in glucose-derived acetate production. In addition, we showed that de novo fatty acid biosynthesis from acetate is essential for this parasite, as demonstrated by a lethal phenotype and metabolic analyses of RNAi-mediated depletion of acetyl-CoA synthetase, catalyzing the first cytosolic step of this pathway.Conclusions/Significance
Acetate produced in the mitochondrion from glucose and threonine is synthetically essential for the long-slender mammalian forms of T. brucei to feed the essential fatty acid biosynthesis through the “acetate shuttle” that was recently described in the procyclic insect form of the parasite. Consequently, key enzymatic steps of this pathway, particularly acetyl-CoA synthetase, constitute new attractive drug targets against trypanosomiasis. 相似文献993.
994.
Jean-Jacques Godon Laure Arcemisbéhère Renaud Escudié Jérôme Harmand Edouard Miambi Jean-Philippe Steyer 《Bioenergy Research》2013,6(3):1063-1081
Over millions of years, living organisms have explored and optimized the digestion of a wide variety of substrates. Engineers who develop anaerobic digestion processes for waste treatment and energy production can learn much from this accumulated ‘experience’. The aim of this work is a survey based on the comparison of 190 digestive tracts (vertebrate and insect) considered as ‘reactors’ and their anaerobic processes. Within a digestive tract, each organ is modeled as a type of reactor (continuous stirred-tank, such reactors in series, plug-flow or batch) associated with chemical aspects such as pH or enzymes. Based on this analysis, each complete digestion process has been rebuilt and classified in accordance with basic structures which take into account the relative size of the different reactors. The results show that all animal digestive structures can be grouped within four basic types. Size and/or position in the structure of the different reactors (pre/post treatment and anaerobic microbial digestion) are closely correlated to the degradability of the feed (substrate). Major common features are: (i) grinding, (ii) an extreme pH compartment, and (iii) correlation between the size of the microbial compartment and the degradability of the feed. Thus, shared answers found by animals during their evolution can be a source of inspiration for engineers in designing optimal anaerobic processes. 相似文献
995.
Zhijun Shen Carole Confolent Patrick Lambert Jean-Luc Poëssel Bénédicte Quilot-Turion Mingliang Yu Ruijuan Ma Thierry Pascal 《Tree Genetics & Genomes》2013,9(6):1435-1446
Anthocyanin-rich peaches, because of their antioxidant properties and their strong attractiveness to consumers, are increasingly considered in French peach varietal innovation programs that integrate plant genomics and classical breeding. In this study, we describe a new blood-flesh trait identified in the ‘Wu Yue Xian’ peach accession from China. ‘Wu Yue Xian’ exhibits a fully red mesocarp during the later stages of fruit development, both with green midrib leaf and normal growth of the tree. This blood-flesh phenotype clearly differs from that determined by a single recessive locus (bf) in ‘Harrow Blood’, a clone showing blood-flesh in both immature and mature fruit associated with red midrib leaf and reduced tree height. We have then provided genetic evidence that blood-flesh phenotype of ‘Wu Yue Xian’ was controlled by a single dominant locus, designated DBF (Dominant Blood-Flesh), in four successive families derived from this accession. A genetic linkage map of the blood-flesh parent (‘D6090’) of the fourth population was constructed, including 102 SSRs spanning a total distance of 562.3 cM in eight linkage groups. Whereas the bf locus is located to linkage group 4, we mapped DBF to the top of linkage group 5, thus proving that DBF and bf loci are not alleles. Among 64 predicted genes in the DBF region (505 kbp), three genes of the dihydroflavonol-4-reductase family were identified as good candidates for the control of the DBF trait. Furthermore, SSR markers flanking DBF, such as AMPP157 and AMPPG178, supply a good basis to implement marker-assisted selection for this trait. 相似文献
996.
Pascale Jolivet Francisca Acevedo Céline Boulard Sabine d'Andréa Jean‐Denis Faure Ajay Kohli Nathalie Nesi Benoit Valot Thierry Chardot 《Proteomics》2013,13(12-13):1836-1849
Oleaginous seeds store lipids in specialized structures called oil bodies (OBs). These organelles consist of a core of neutral lipids bound by proteins embedded in a phospholipid monolayer. OB proteins are well conserved in plants and have long been grouped into only two categories: structural proteins or enzymes. Recent work, however, which identified other classes of proteins associated with OBs, clearly shows that this classification is obsolete. Proteomics‐mediated OB protein identification is facilitated in plants for which the genome is sequenced and annotated. However, it is not clear whether this knowledge can be dependably transposed to less well‐characterized plants, including the well‐established commercial sources of seed oil as well as the many others being proposed as novel sources for biodiesel, especially in Africa and Asia. Toward an update of the current data available on OB proteins this review discusses (i) the specific difficulties for proteomic studies of organelles; (ii) a 2012 census of the proteins found in seed OBs from various crops; (iii) the oleosin composition of OBs and their role in organelle stability; (iv) PTM of OB proteins as an emerging field of investigation; and finally we describe the emerging model of the OB proteome from oilseed crops. 相似文献
997.
Olivier Véron Jean-Philippe Blondeau Michał Grabiec Aleksandra Wolak Krzystof Dzierżęga Nadège Ollier François Goutaland Mohamed Chérif Sow Stéphane Pellerin Nadia Pellerin 《Plasmonics (Norwell, Mass.)》2013,8(1):93-103
Silver-exchanged silicate glass has been irradiated by 532-nm pulsed Nd:YAG laser in order to locally form metallic nanoparticles. The particular interest of this process is to locally control the silver nanoparticles (NPs) growth. Silver ions are exchanged with sodium ions near the glass surface after dumping of a silicate glass few minutes in silver and sodium nitrates molten salt. A low-energy density laser exposure (0.239 J/cm2) chosen at the ablation threshold allows to observe the kinetics of the silver NPs growth according to the increasing shots number. An on-line optical measurement is carried out after each shot to identify the most important steps during the irradiation process. According to this measurement, we have determined four steps highlighted by UV/Visible spectrophotometry and we have identified the influence of located surface plasmon resonance. Three combined material analysis methods were used to understand the glass/laser interaction mechanism: we outlined the material volume variations by profilometric method, the element distribution by scanning electron microscopy and finally the structural distribution of the irradiated region by a local infrared investigation. The trend for NPs formation revealed by the UV/Visible spectrophotometry is thus explained by the formation of a ring expelled from a central hole. We highlight that the on-line extinction measurement can be used to data process the NPs evolution. 相似文献
998.
999.
Rapha?l Laurenceau Gérard Péhau-Arnaudet Sonia Baconnais Joseph Gault Christian Malosse Annick Dujeancourt Nathalie Campo Julia Chamot-Rooke Eric Le Cam Jean-Pierre Claverys Rémi Fronzes 《PLoS pathogens》2013,9(6)
Natural genetic transformation is widely distributed in bacteria and generally occurs during a genetically programmed differentiated state called competence. This process promotes genome plasticity and adaptability in Gram-negative and Gram-positive bacteria. Transformation requires the binding and internalization of exogenous DNA, the mechanisms of which are unclear. Here, we report the discovery of a transformation pilus at the surface of competent Streptococcus pneumoniae cells. This Type IV-like pilus, which is primarily composed of the ComGC pilin, is required for transformation. We provide evidence that it directly binds DNA and propose that the transformation pilus is the primary DNA receptor on the bacterial cell during transformation in S. pneumoniae. Being a central component of the transformation apparatus, the transformation pilus enables S. pneumoniae, a major Gram-positive human pathogen, to acquire resistance to antibiotics and to escape vaccines through the binding and incorporation of new genetic material. 相似文献
1000.
Géraldine De Muylder Sylvie Daulouède Laurence Lecordier Pierrick Uzureau Yannick Morias Jan Van Den Abbeele Guy Caljon Michel Hérin Philippe Holzmuller Silla Semballa Pierrette Courtois Luc Vanhamme Beno?t Stijlemans Patrick De Baetselier Michael P. Barrett Jillian L. Barlow Andrew N. J. McKenzie Luke Barron Thomas A. Wynn Alain Beschin Philippe Vincendeau Etienne Pays 《PLoS pathogens》2013,9(10)