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71.
Sandra Matthijs Georges Laus Jean-Marie Meyer Kourosch Abbaspour-Tehrani Mathias Schäfer Herbert Budzikiewicz Pierre Cornelis 《Biometals》2009,22(6):951-964
Pseudomonas entomophila L48 is a recently identified entomopathogenic bacterium which, upon ingestion, kills Drosophila melanogaster, and is closely related to P. putida. The complete genome of this species has been sequenced and therefore a genomic, genetic and structural analysis of the siderophore-mediated
iron acquisition was undertaken. P. entomophila produces two siderophores, a structurally new and unique pyoverdine and the secondary siderophore pseudomonine, already described
in P. fluorescens species. Structural analysis of the pyoverdine produced by the closely related P. putida KT2440 showed that this strain produces an already characterised pyoverdine, but different from P. entomophila, and no evidence was found for the production of a second siderophore. Growth stimulation assays with heterologous pyoverdines
demonstrated that P. entomophila is able to utilize a large variety of structurally distinct pyoverdines produced by other Pseudomonas species. In contrast, P. putida KT2440 is able to utilize only its own pyoverdine and the pyoverdine produced by P. syringae LMG 1247. Our data suggest that although closely related, P. entomophila is a more efficient competitor for iron than P. putida. 相似文献
72.
The Pseudomonas genus belongs to the γ division of Proteobacteria and many species produce the characteristic yellow–green siderophore pyoverdine,
and often a second siderophore, of lower affinity for iron. These bacteria are known for their ability to colonize different
ecological niches and for their versatile metabolism. It is therefore not surprising that they are endowed with the capacity
to take up exogenous xenosiderophores via different TonB-dependent receptors. Uptake of iron is controlled by the central
regulator Fur, and via extracytoplasmic sigma factors or other types of regulators (two-component systems, AraC regulators).
In this review the Fur regulon (experimentally proven and/or predicted) of P. aeruginosa will be presented. An interesting feature revealed by this analysis of Fur-regulated genes is the overlap between the iron
and the sulfur regulons as well with the quorum sensing system. 相似文献
73.
Wendy Vleugels Els Schollen Gert Matthijs 《Biochemical and biophysical research communications》2009,390(3):769-576
Congenital Disorders of Glycosylation (CDG) are a group of inherited disorders caused by deficiencies in glycosylation. Since 1980, 14 CDG type I (CDG-I) defects have been identified in the endoplasmic reticulum, all affecting the assembly of the oligosaccharide precursor. However, the number of unsolved CDG-I (CDG-Ix) patients displaying protein hypoglycosylation in combination with an apparently normal assembly of the oligosaccharide precursor is currently expanding.We hypothesized that the hypoglycosylation observed in some of these patients could be caused by a deficiency in the transfer of the oligosaccharide precursor onto protein, a reaction catalyzed by the oligosaccharyltransferase (OST) complex. For this purpose, the different subunits of the OST complex were screened in 27 CDG-Ix patients for whom structural analysis of the lipid-linked oligosaccharides revealed a normal level and intact structure of the oligosaccharide precursor. Among these 27 patients, one was identified with a homozygous missense mutation (c.1121G > A; p.G374D) in the ribophorin 2 (RPN2) subunit of the OST complex. The pathogenic nature of this mutation remains unproven due to the complexity of tackling a possible OST defect. 相似文献
74.
Francisco Javier Ruiz-Sánchez Belén Lázaro Calatayud Matthijs Freudenthal 《Comptes Rendus Palevol》2009,8(4):375-384
A new species of Eomyops, Eomyops noeliae, is described. from the locality MT-20A (Morteral section, Magro basin, eastern Spain). It is intermediate in size between the large eomiid, E. hebeiseni, and the small species of the group E. catalaunicus, E. bodvanus and E. oppligeri. The age range is Lower Aragonian. MT-20A is located between deposits that contain Megacricetodon primitivus and M. collongensis. Morphologically, E. noeliae sp. nov. is clearly different from the rest of species of the genus, due to an important reduction of the lingual anteroloph of M1,2,3 and the labial anterolophid of M3. The lower incisor shows two parallel ridges along the enamel like the type species of the genus, E. catalaunicus. This character is basic for the distinction between Eomyops and the North American genus Leptodontomys. 相似文献
75.
Matthijs Raaben Henk-Jan Prins Anton C. Martens Peter J. M. Rottier Cornelis A. M. de Haan 《Cellular microbiology》2009,11(5):825-841
Bioluminescence imaging (BLI) is a powerful new method to study virus dissemination in the live animal. Here we used this method to monitor the spatial and temporal progression of mouse hepatitis coronavirus (MHV) infection in mice using luciferase-expressing viruses. Upon intranasal inoculation, virus replication could initially be observed in the nasal cavity and the cervical lymph nodes, after which the infection spread to the brain and frequently to the eyes. The kinetics of virus spread to and clearance from the brain appeared to depend on the inoculation dose. After intraperitoneal inoculation, virus replication was predominantly observed in the liver and occasionally in the intestines, but interestingly also in the tail and paws. BLI thus elucidated new anatomic locations of virus replication. Furthermore, MHV dissemination was shown to be critically depended on the viral spike protein, but also on the mouse strain used. Widespread dissemination was observed in mice lacking a functional type I interferon response. The importance of the type I interferon system in limiting viral spread was also demonstrated by the administration of type I interferons to mice. Our results provide new insights in coronavirus pathogenesis and demonstrate the potential of BLI to study coronavirus–host interactions in vivo . 相似文献
76.
van Veelen M 《Journal of theoretical biology》2006,242(3):790-797
Models of kin or group selection usually feature only one possible fitness transfer. The phenotypes are either to make this transfer or not to make it and for any given fitness transfer, Hamilton's rule predicts which of the two phenotypes will spread. In this article we allow for the possibility that different individuals or different generations face similar, but not necessarily identical possibilities for fitness transfers. In this setting, phenotypes are preference relations, which concisely specify behaviour for a range of possible fitness transfers (rather than being a specification for only one particular situation an animal or human can be in). For this more general set-up, we find that only preference relations that are linear in fitnesses can be explained using models of kin selection and that the same applies to a large class of group selection models. This provides a new implication of hierarchical selection models that could in principle falsify them, even if relatedness--or a parameter for assortativeness--is unknown. The empirical evidence for humans suggests that hierarchical selection models alone are not enough to explain their other-regarding or altruistic behaviour. 相似文献
77.
Background
The variance explained by genetic variants as identified in (genome-wide) genetic association studies is typically small compared to family-based heritability estimates. Explanations of this ‘missing heritability’ have been mainly genetic, such as genetic heterogeneity and complex (epi-)genetic mechanisms.Methodology
We used comprehensive simulation studies to show that three phenotypic measurement issues also provide viable explanations of the missing heritability: phenotypic complexity, measurement bias, and phenotypic resolution. We identify the circumstances in which the use of phenotypic sum-scores and the presence of measurement bias lower the power to detect genetic variants. In addition, we show how the differential resolution of psychometric instruments (i.e., whether the instrument includes items that resolve individual differences in the normal range or in the clinical range of a phenotype) affects the power to detect genetic variants.Conclusion
We conclude that careful phenotypic data modelling can improve the genetic signal, and thus the statistical power to identify genetic variants by 20–99%. 相似文献78.
Aguirre von Wobeser E Ibelings BW Bok J Krasikov V Huisman J Matthijs HC 《Plant physiology》2011,155(3):1445-1457
Physiological adaptation and genome-wide expression profiles of the cyanobacterium Synechocystis sp. strain PCC 6803 in response to gradual transitions between nitrogen-limited and light-limited growth conditions were measured in continuous cultures. Transitions induced changes in pigment composition, light absorption coefficient, photosynthetic electron transport, and specific growth rate. Physiological changes were accompanied by reproducible changes in the expression of several hundred open reading frames, genes with functions in photosynthesis and respiration, carbon and nitrogen assimilation, protein synthesis, phosphorus metabolism, and overall regulation of cell function and proliferation. Cluster analysis of the nearly 1,600 regulated open reading frames identified eight clusters, each showing a different temporal response during the transitions. Two large clusters mirrored each other. One cluster included genes involved in photosynthesis, which were up-regulated during light-limited growth but down-regulated during nitrogen-limited growth. Conversely, genes in the other cluster were down-regulated during light-limited growth but up-regulated during nitrogen-limited growth; this cluster included several genes involved in nitrogen uptake and assimilation. These results demonstrate complementary regulation of gene expression for two major metabolic activities of cyanobacteria. Comparison with batch-culture experiments revealed interesting differences in gene expression between batch and continuous culture and illustrates that continuous-culture experiments can pick up subtle changes in cell physiology and gene expression. 相似文献
79.
van Zimmeren E Vanneste S Matthijs G Vanhaverbeke W Van Overwalle G 《Trends in biotechnology》2011,29(11):569-576
The biopharmaceutical industry is slowly absorbing the idea of collaborative patent licensing models. Recently, two patent pools for developing countries have been launched: the Pool for Open Innovation against Neglected Tropical Diseases initiated by GlaxoSmithKline (GSK), which is referred to as the BIO Ventures for Global Health (BVGH) pool, and the Medicines Patent Pool (MPP) initiated by UNITAID. Various organizations have recommended using pools or clearinghouses beyond the humanitarian dimension where many patents are owned by many different actors. As a first attempt, MPEG LA, which administers patent pools in various technology fields, is now setting up a clearinghouse for patents related to molecular diagnostics. These examples as well as the results from an empirical study provide useful insights for the design and administration of future pools and clearinghouses in the life sciences. 相似文献
80.
Ype de Jong Johannes Henricus Francisca Maria Pinckaers Robin Marco ten Brinck Augustinus Aizo Beent Lycklama à Nijeholt Olaf Matthijs Dekkers 《PloS one》2014,9(7)