排序方式: 共有141条查询结果,搜索用时 265 毫秒
41.
Gaelle Marinoni Martine Manuel Randi Fns Petersen Jeanne Hvidtfeldt Pavol Sulo Jure Pikur 《Journal of bacteriology》1999,181(20):6488-6496
The genus Saccharomyces consists of several species divided into the sensu stricto and the sensu lato groups. The genomes of these species differ in the number and organization of nuclear chromosomes and in the size and organization of mitochondrial DNA (mtDNA). In the present experiments we examined whether these yeasts can exchange DNA and thereby create novel combinations of genetic material. Several putative haploid, heterothallic yeast strains were isolated from different Saccharomyces species. All of these strains secreted an a- or alpha-like pheromone recognized by S. cerevisiae tester strains. When interspecific crosses were performed by mass mating between these strains, hybrid zygotes were often detected. In general, the less related the two parental species were, the fewer hybrids they gave. For some crosses, viable hybrids could be obtained by selection on minimal medium and their nuclear chromosomes and mtDNA were examined. Often the frequency of viable hybrids was very low. Sometimes putative hybrids could not be propagated at all. In the case of sensu stricto yeasts, stable viable hybrids were obtained. These contained both parental sets of chromosomes but mtDNA from only one parent. In the case of sensu lato hybrids, during genetic stabilization one set of the parental chromosomes was partially or completely lost and the stable mtDNA originated from the same parent as the majority of the nuclear chromosomes. Apparently, the interspecific hybrid genome was genetically more or less stable when the genetic material originated from phylogenetically relatively closely related parents; both sets of nuclear genetic material could be transmitted and preserved in the progeny. In the case of more distantly related parents, only one parental set, and perhaps some fragments of the other one, could be found in genetically stabilized hybrid lines. The results obtained indicate that Saccharomyces yeasts have a potential to exchange genetic material. If Saccharomyces isolates could mate freely in nature, horizontal transfer of genetic material could have occurred during the evolution of modern yeast species. 相似文献
42.
The genetics and genomics of insecticide resistance 总被引:13,自引:0,他引:13
The past ten years have seen the elucidation of the molecular basis of insect resistance to many chemical insecticides. Target genes, mostly in the nervous system, have been identified and cloned from Drosophila melanogaster and resistance-associated mutations have been examined in a range of pest insects. More recently, with the advent of annotated insect genomes, resistance mediated by complex multi-gene enzyme systems such as esterases, cytochrome p450s and glutathione-S-transferases has also been elucidated. In this article, we review the impact of Drosophila genetics on the field of insect resistance and focus on the current and future impact of genomics. These studies enable us to address three fundamental questions in the evolution of resistance. How many genes are involved? How many mutations are there within these genes? How often do these mutations arise in natural populations? 相似文献
43.
High-throughput polyribosome fractionation 总被引:1,自引:0,他引:1
Polyribosome sedimentation velocity centrifugation can be used to identify differential regulation of the translation of mRNAs. However, ultracentrifugation presents practical limitations on the number of sedimentation velocity gradients that can be run simultaneously. A method for sedimentation velocity analysis of polyribosomes is presented that is based on low-speed centrifugation of sucrose gradients prepared in deep 96-well plates, the advantage of which is that hundreds of polyribosome fractionations can be performed simultaneously in a tabletop centrifuge. 相似文献
44.
Bottomley MJ Stier G Pennacchini D Legube G Simon B Akhtar A Sattler M Musco G 《The Journal of biological chemistry》2005,280(12):11505-11512
Mutations in the autoimmune regulator protein AIRE1 cause a monogenic autosomal recessively inherited disease: autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). AIRE1 is a multidomain protein that harbors two plant homeodomain (PHD)-type zinc fingers. The first PHD finger of AIRE1 is a mutational hot spot, to which several pathological point mutations have been mapped. Using heteronuclear NMR spectroscopy, we determined the solution structure of the first PHD finger of AIRE1 (AIRE1-PHD1), and characterized the peptide backbone mobility of the domain. We performed a conformational analysis of pathological AIRE1-PHD1 mutants that allowed us to rationalize the structural impact of APECED-causing mutations and to identify an interaction site with putative protein ligands of the AIRE1-PHD1 domain. The structure unequivocally exhibits the canonical PHD finger fold, with a highly conserved tryptophan buried inside the structure. The PHD finger is stabilized by two zinc ions coordinated in an interleaved (cross-brace) scheme. This zinc coordination resembles RING finger domains, which can function as E3 ligases in the ubiquitination pathway. Based on this fold similarity, it has been suggested that PHD fingers might also function as E3 ligases, although this hypothesis is controversial. At variance to a previous report, we could not find any evidence that AIRE1-PHD1 has an intrinsic E3 ubiquitin ligase activity, nor detect any direct interaction between AIRE1-PHD1 and its putative cognate E2. Consistently, we show that the AIRE1-PHD1 structure is clearly distinct from the RING finger fold. Our results point to a function of the AIRE1-PHD1 domain in protein-protein interactions, which is impaired in some APECED mutations. 相似文献
45.
Gaelle Boncompain Constanze Müller Vannary Meas-Yedid Philippe Schmitt-Kopplin Paul B. Lazarow Agathe Subtil 《PloS one》2014,9(1)
Chlamydia trachomatis is an obligate intracellular pathogen responsible for loss of eyesight through trachoma and for millions of cases annually of sexually transmitted diseases. The bacteria develop within a membrane-bounded inclusion. They lack enzymes for several biosynthetic pathways, including those to make some phospholipids, and exploit their host to compensate. Three-dimensional fluorescence microscopy demonstrates that small organelles of the host, peroxisomes, are translocated into the Chlamydia inclusion and are found adjacent to the bacteria. In cells deficient for peroxisome biogenesis the bacteria are able to multiply and give rise to infectious progeny, demonstrating that peroxisomes are not essential for bacterial development in vitro. Mass spectrometry-based lipidomics reveal the presence in C. trachomatis of plasmalogens, ether phospholipids whose synthesis begins in peroxisomes and have never been described in aerobic bacteria before. Some of the bacterial plasmalogens are novel structures containing bacteria-specific odd-chain fatty acids; they are not made in uninfected cells nor in peroxisome-deficient cells. Their biosynthesis is thus accomplished by the metabolic collaboration of peroxisomes and bacteria. 相似文献
46.
Ming Hu Inês Cebola Gaelle Carrat Shuying Jiang Sameena Nawaz Amna Khamis Mickaël Canouil Philippe Froguel Anke Schulte Michele Solimena Mark Ibberson Piero Marchetti Fabian L. Cardenas-Diaz Paul J. Gadue Benoit Hastoy Leonardo Almeida-Souza Harvey McMahon Guy A. Rutter 《Cell reports》2021,34(11):108881
47.
Joana Rocha Magali Audry Gaelle Pesce Valérie Chazalet Maryse A. Block Eric Maréchal Christelle Breton 《Biochimie》2013
Monogalactosyldiacylglycerol, the major lipid of plants and algal plastids, is synthesized by MGDG synthases (MGD). MGDs belong to the large glycosyltransferase family. They catalyze the transfer of a galactose residue from the donor UDP-Gal to a 1,2-sn-diacylglycerol acceptor. MGDs are monotopic proteins localized in the plastid envelope and, as such, they are difficult to purify. This study re-examined previous purification procedures and aimed to set up a standard protocol for expression and purification of recombinant MGD1, addressing problems frequently encountered with the purification of glycosyltransferases, particularly protein aggregation, and enabling crystallization for structural studies. Briefly, His-tagged versions of MGD1 were expressed in Escherichia coli and purified by a two-step procedure, including immobilized metal affinity chromatography and size-exclusion chromatography. We demonstrated that E. coli is an appropriate host cell to produce a soluble and active form of MGD1. We also investigated the effects of various buffers and additives used during the purification and concentration steps on the biochemical behavior of the enzyme. The protocol we developed typically yields milligram quantities of pure and homogenous protein material and proved suitable for crystallization and biochemical studies. We also revisited the conditions for activity tests and effects of known positive effectors of MGD1 such as phosphatidic acid and phosphatidylglycerol. 相似文献
48.
Jan G Delorme V David V Revenu C Rebollo A Cayla X Tardieux I 《The Biochemical journal》2007,401(3):711-719
Toxofilin is a 27 kDa protein isolated from the human protozoan parasite Toxoplasma gondii, which causes toxoplasmosis. Toxofilin binds to G-actin, and in vitro studies have shown that it controls elongation of actin filaments by sequestering actin monomers. Toxofilin affinity for G-actin is controlled by the phosphorylation status of its Ser53, which depends on the activities of a casein kinase II and a type 2C serine/threonine phosphatase (PP2C). To get insights into the functional properties of toxofilin, we undertook a structure-function analysis of the protein using a combination of biochemical techniques. We identified a domain that was sufficient to sequester G-actin and that contains three peptide sequences selectively binding to G-actin. Two of these sequences are similar to sequences present in several G- and F-actin-binding proteins, while the third appears to be specific to toxofilin. Additionally, we identified two toxofilin domains that interact with PP2C, one of which contains the Ser53 substrate. In addition to characterizing the interacting domains of toxofilin with its partners, the present study also provides information on an in vivo-based approach to selectively and competitively disrupt the protein-protein interactions that are important to parasite motility. 相似文献
49.
Mio Ikeda Asako Furukohri Gaelle Philippin Edward Loechler Masahiro Tatsumi Akiyama Tsutomu Katayama Robert P. Fuchs Hisaji Maki 《Nucleic acids research》2014,42(13):8461-8472
Escherichia coli DNA polymerase IV (Pol IV, also known as DinB) is a Y-family DNA polymerase capable of catalyzing translesion DNA synthesis (TLS) on certain DNA lesions, and accumulating data suggest that Pol IV may play an important role in copying various kinds of spontaneous DNA damage including N2-dG adducts and alkylated bases. Pol IV has a unique ability to coexist with Pol III on the same β clamp and to positively dissociate Pol III from β clamp in a concentration-dependent manner. Reconstituting the entire process of TLS in vitro using E. coli replication machinery and Pol IV, we observed that a replication fork stalled at (−)-trans-anti-benzo[a]pyrene-N2-dG lesion on the leading strand was efficiently and quickly recovered via two sequential switches from Pol III to Pol IV and back to Pol III. Our results suggest that TLS by Pol IV smoothes the way for the replication fork with minimal interruption. 相似文献
50.
Enrique Casalino Christophe Choquet Agathe Leleu Romain Hellmann Mathias Wargon Gaelle Juillien Yazdan Yazdanpanah Elisabeth Bouvet 《PloS one》2014,9(8)