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排序方式: 共有117条查询结果,搜索用时 31 毫秒
1.
Summary Chromosome 17ps was identified in the mother and daughter but not the father of a normal family with no history of congenital abnormality. In addition to G-band and Ag-NOR staining, previously used to study this abnormality, we applied N-band and C-band techniques. Our results showed that 17ps has no demonstrable ribosomal cistron or constitutive heterochromatin. 相似文献
2.
Xiao Lin Tianqiao Song Sebastian Fairhead Kamil Witek Agathe Jouet Florian Jupe Agnieszka I. Witek Hari S. Karki Vivianne G. A. A. Vleeshouwers Ingo Hein Jonathan D. G. Jones 《Molecular Plant Pathology》2020,21(11):1502-1512
Potato late blight, caused by the oomycete pathogen Phytophthora infestans, significantly hampers potato production. Recently, a new Resistance to Phytophthora infestans (Rpi) gene, Rpi-amr1, was cloned from a wild Solanum species, Solanum americanum. Identification of the corresponding recognized effector (Avirulence or Avr) genes from P. infestans is key to elucidating their naturally occurring sequence variation, which in turn informs the potential durability of the cognate late blight resistance. To identify the P. infestans effector recognized by Rpi-amr1, we screened available RXLR effector libraries and used long read and cDNA pathogen-enrichment sequencing (PenSeq) on four P. infestans isolates to explore the untested effectors. Using single-molecule real-time sequencing (SMRT) and cDNA PenSeq, we identified 47 highly expressed effectors from P. infestans, including PITG_07569, which triggers a highly specific cell death response when transiently coexpressed with Rpi-amr1 in Nicotiana benthamiana, suggesting that PITG_07569 is Avramr1. Here we demonstrate that long read and cDNA PenSeq enables the identification of full-length RXLR effector families and their expression profile. This study has revealed key insights into the evolution and polymorphism of a complex RXLR effector family that is associated with the recognition by Rpi-amr1. 相似文献
3.
Mathias Weber Alexandra R. Wey-Fabrizius Lars Podsiadlowski Alexander Witek Ralph O. Schill László Sugár Holger Herlyn Thomas Hankeln 《Molecular phylogenetics and evolution》2013,66(1):182-189
The metazoan taxon Syndermata (Monogononta, Bdelloidea, Seisonidea, Acanthocephala) comprises species with vastly different lifestyles. The focus of this study is on the phylogeny within the syndermatan subtaxon Acanthocephala (thorny-headed worms, obligate endoparasites). In order to investigate the controversially discussed phylogenetic relationships of acanthocephalan subtaxa we have sequenced the mitochondrial (mt) genomes of Echinorhynchus truttae (Palaeacanthocephala), Paratenuisentis ambiguus (Eoacanthocephala), Macracanthorhynchus hirudinaceus (Archiacanthocephala), and Philodina citrina (Bdelloidea). In doing so, we present the largest molecular phylogenetic dataset so far for this question comprising all major subgroups of Acanthocephala. Alongside with publicly available mt genome data of four additional syndermatans as well as 18 other lophotrochozoan (spiralian) taxa and one outgroup representative, the derived protein-coding sequences were used for Maximum Likelihood as well as Bayesian phylogenetic analyses. We achieved entirely congruent results, whereupon monophyletic Archiacanthocephala represent the sister taxon of a clade comprising Eoacanthocephala and monophyletic Palaeacanthocephala (Echinorhynchida). This topology suggests the secondary loss of lateral sensory organs (sensory pores) within Palaeacanthocephala and is further in line with the emergence of apical sensory organs in the stem lineage of Archiacanthocephala. 相似文献
4.
Magdalena Witek Luca Pietro Casacci Francesca Barbero Dario Patricelli Marco Sala Simone Bossi Massimo Maffei Michal Woyciechowski Emilio Balletto Simona Bonelli 《Biological journal of the Linnean Society. Linnean Society of London》2013,109(3):699-709
Myrmica ant colonies host numerous insect species, including the larvae of Maculinea butterflies and Microdon myrmicae hoverflies. Little is known about the interspecific relationships among these social parasites and their host ants occurring in sympatric populations. We investigated communities of social parasites to assess the strategies allowing them to share the same pool of resources (i.e. Myrmica colonies). The present study was carried out at five sites inhabited by different social parasite communities, each comprising varying proportions of Maculinea teleius, Maculinea nausithous, Maculinea alcon, and Microdon myrmicae. We investigated their spatial distributions, host segregation, the degree of chemical similarity between social parasites and hosts, and temporal overlaps in colony resource exploitation. Spatial segregation among social parasites was found in two populations and it arises from microhabitat preferences and biological interactions. Local conditions can drive selection on one social parasite to use a Myrmica host species that is not exploited by other social parasites. Myrmica scabrinodis and Myrmica rubra nests infested by larvae of two social parasite species were found and the most common co‐occurrence was between Ma. teleius and Mi. myrmicae. The successful coexistence of these two species derives from their exploitation of the host colony resources at different times of the year. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 699–709. 相似文献
5.
6.
The effect of the newly synthesized phosphonic compound dibutyl 2-octylamino-2-propanephosphonate (DBOP) on the growth of the aquatic plant Spirodela oligorrhiza and stability of red blood cells (RBC) and planar lipid membranes (BLM) was studied to determine its physiological activity and, if possible, correlate this activity to compound-induced changes in the mechanical properties of the model membranes. The measure of the phytotoxicity was the DBOP concentration causing 50% plant growth retardation, while measures of stability of model membranes were 100% hemolysis of RBC and a critical concentration of DBOP causing BLM destruction in no more that 3 min. These data were compared with those for dibutyl 1-butylamino-1-cyclohexanephosphonate (DBBC) and diethyl 9-butylamino-9-fluorenephosphonate (DEBF) known for their physiological activities. Both DBBC and DEBF influenced Spirodela growth significantly less than DBOP Destabilization of the model membrane caused by DBBC and DBOP was similar whereas DEBF exerted a weak influence on RBC and BLM stability. The results indicate that the physiological activities of DBOP and DEBF are not limited to the lipid phase of biological membranes and may involve also disturbance of metabolic processes. 相似文献
7.
Formation of thiobarbituric acid-reactive substances (TBRS; nmol/mg lipids) indicative of lipid peroxidation was measured
in whole cells and in isolated plasma membrane lipids from three yeast species differing in oxidant sensitivity (Schizosaccharomyces pombe, Saccharomyces cerevisiae andRhodotorula glutinis) after exposure to the Fenton reagent, FeII, H2O2,tert-butyl hydroperoxide (TBHP) and azo compounds (AAPH, ACHN). In whole cells, spontaneous TBRS formation rose in the sequenceS. pombe<S. cerevisiae<R. glutinis (1:∼5:∼7). Oxidants increased the TBRS production 13–18 fold in the sequence FeII∼TBHP>AAPH∼ACHN∼Fe-Fenton>H2O2. This increase need not be solely due to increased lipid peroxidation. In isolated plasma membrane lipids from all three
species, the spontaneous TBRS production referred to 1 mg lipids was 9–13-fold higher than in whole cells. InS. pombe lipids, only TBHP increased the TBRS production. In lipids fromS. cerevisiae andR. glutinis, all added oxidants increased the spontaneous TBRS production 2–3 times in the sequence TBHP>ACHN>AAPH>FeII>Fe-Fenton>H2O2. Oxidant-induced TBRS production in both whole cells and isolated membrane lipids was partially suppressed by the lipid peroxidation
inhibitors 2,6-di-tert-butyl-4-methylphenol (“butylated hydroxytoluene”; BHT) and the newly synthesized PYA12 compound. Both agents were more effective
in isolated lipids than in whole cells and against OH-producing than against ROO-or RO-producing oxidants. Yeast membrane
lipids, which are generally poor in polyunsaturated fatty acids, are thus subject to perceptible lipid peroxidation. 相似文献
8.
Hausdorf B Helmkampf M Meyer A Witek A Herlyn H Bruchhaus I Hankeln T Struck TH Lieb B 《Molecular biology and evolution》2007,24(12):2723-2729
Phylogenetic analyses based on 79 ribosomal proteins of 38 metazoans, partly derived from 6 new expressed sequence tag projects for Ectoprocta, Entoprocta, Sipuncula, Annelida, and Acanthocephala, indicate the monophyly of Bryozoa comprising Ectoprocta and Entoprocta, 2 taxa that have been separated for more than a century based on seemingly profound morphological differences. Our results also show that bryozoans are more closely related to Neotrochozoa, including molluscs and annelids, than to Syndermata, the latter comprising Rotifera and Acanthocephala. Furthermore, we find evidence for the position of Sipuncula within Annelida. These findings suggest that classical developmental and morphological key characters such as cleavage pattern, coelomic cavities, gut architecture, and body segmentation are subject to greater evolutionary plasticity than traditionally assumed. 相似文献
9.
Witek-Krowiak A Witek J Gruszczyńska A Szafran RG Koźlecki T Modelski S 《World journal of microbiology & biotechnology》2011,27(8):1961-1964
Classic methods of biosurfactant separation are difficult and require large amounts of organic solvents, thus generate high
amounts of waste. This work presents and discusses in detail an original procedure to separate rhamnolipid from fermentation
broth using high performance membrane techniques. Due to the unique properties of surface active agents, such as capability
of forming aggregates above the critical micelle concentration, it is possible to easily purify the biosurfactant with high
efficacy using inexpensive and commonly used membranes. In this article, two-stage ultrafiltration is proposed as a method
for separating and purifying rhamnolipid from the culture medium. The obtained purified rhamnolipid solution was capable of
reducing surface tension of water down to 28.6 mN/m at critical micelle concentration of 40 mg/l. Separation of rhamnolipid
was confirmed by HPLC; three types of rhamnolipids were identified (RL1, RL2, RL4), with considerable predominance of RL2. 相似文献
10.
Klammt C Perrin MH Maslennikov I Renault L Krupa M Kwiatkowski W Stahlberg H Vale W Choe S 《Protein science : a publication of the Protein Society》2011,20(6):1030-1041
G-protein coupled receptors (GPCRs) constitute the largest family of intercellular signaling molecules and are estimated to be the target of more than 50% of all modern drugs. As with most integral membrane proteins (IMPs), a major bottleneck in the structural and biochemical analysis of GPCRs is their expression by conventional expression systems. Cell-free (CF) expression provides a relatively new and powerful tool for obtaining preparative amounts of IMPs. However, in the case of GPCRs, insufficient homogeneity of the targeted protein is a problem as the in vitro expression is mainly done with detergents, in which aggregation and solubilization difficulties, as well as problems with proper folding of hydrophilic domains, are common. Here, we report that using CF expression with the help of a fructose-based polymer, NV10 polymer (NVoy), we obtained preparative amounts of homogeneous GPCRs from the three GPCR families. We demonstrate that two GPCR B family members, corticotrophin-releasing factor receptors 1 and 2β are not only solubilized in NVoy but also have functional ligand-binding characteristics with different agonists and antagonists in a detergent-free environment as well. Our findings open new possibilities for functional and structural studies of GPCRs and IMPs in general. 相似文献