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1.
Between 1988 and 1994, 58 beavers were translocated from the Elbe region (Germany) to the Netherlands. In 43 animals, radio-transmitters were implanted with a pulse interval which was dependent on body temperature; subsequently, 22 of the released animals were found dead and the cause of death was investigated. Infectious diseases were the most important cause of death (50%), in particular yersiniosis and leptospirosis. Yersiniosis is relatively rare in the source population along the Elbe, and leptospirosis has not been reported before in beavers. We hypothesize that the immune system of the translocated animals was weakened by stress at a time of exposure to new pathogens. In future translocations of beavers, we recommend to reduce the stress, improve the hygiene, and to vaccinate against Yersinia pseudotuberculosis and leptospirosis prior to the release. 相似文献
2.
Phillip A Patten Russell J Howard Willem PC Stemmer 《Current opinion in biotechnology》1997,8(6):724-733
DNA shuffling is a practical process for directed molecular evolution which uses recombination to dramatically accelerate the rate at which one can evolve genes. Single and multigene traits that require many mutations for improved phenotypes can be evolved rapidly. DNA shuffling technology has been significantly enhanced in the past year, extending its range of applications to small molecule pharmaceuticals, pharmaceutical proteins, gene therapy vehicles and transgenes, vaccines and evolved viruses for vaccines, and laboratory animal models. 相似文献
3.
High-throughput proteomics is made possible by a combination of modern mass spectrometry instruments capable of generating many millions of tandem mass (MS(2)) spectra on a daily basis and the increasingly sophisticated associated software for their automated identification. Despite the growing accumulation of collections of identified spectra and the regular generation of MS(2) data from related peptides, the mainstream approach for peptide identification is still the nearly two decades old approach of matching one MS(2) spectrum at a time against a database of protein sequences. Moreover, database search tools overwhelmingly continue to require that users guess in advance a small set of 4-6 post-translational modifications that may be present in their data in order to avoid incurring substantial false positive and negative rates. The spectral networks paradigm for analysis of MS(2) spectra differs from the mainstream database search paradigm in three fundamental ways. First, spectral networks are based on matching spectra against other spectra instead of against protein sequences. Second, spectral networks find spectra from related peptides even before considering their possible identifications. Third, spectral networks determine consensus identifications from sets of spectra from related peptides instead of separately attempting to identify one spectrum at a time. Even though spectral networks algorithms are still in their infancy, they have already delivered the longest and most accurate de novo sequences to date, revealed a new route for the discovery of unexpected post-translational modifications and highly-modified peptides, enabled automated sequencing of cyclic non-ribosomal peptides with unknown amino acids and are now defining a novel approach for mapping the entire molecular output of biological systems that is suitable for analysis with tandem mass spectrometry. Here we review the current state of spectral networks algorithms and discuss possible future directions for automated interpretation of spectra from any class of molecules. 相似文献
4.
Eva Veronesi Frank Antony Simon Gubbins Nick Golding Alison Blackwell Peter PC. Mertens Joe Brownlie Karin E. Darpel Philip S. Mellor Simon Carpenter 《PloS one》2013,8(8)
Background
Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006–2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture.Methodology/Principal Findings
A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination.Conclusions/Significance
Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed. 相似文献5.
Phylogenetic relationships were determined for 76 partial P-element
sequences from 14 species of the melanogaster species group within the
Drosophila subgenus Sophophora. These results are examined in the context
of the phylogeny of the species from which the sequences were isolated.
Sequences from the P-element family fall into distinct subfamilies, or
clades, which are often characteristic for particular species subgroups.
When examined locally among closely related species, the evolution of P
elements is characterized by vertical transmission, whereby the P-element
phylogeny traces the species phylogeny. On a broader scale, however, the
P-element phylogeny is not congruent with the species phylogeny. One
feature of P-element evolution in the melanogaster group is the presence of
more than one P-element subfamily, differing by as much as 36%, in the
genomes of some species. Thus, P elements from several individual species
are not monophyletic, and a likely explanation for the incongruence between
P-element and species phylogenies is provided by the comparison of
paralogous sequences. In certain instances, horizontal transfer seems to be
a valid alternative explanation for lack of congruence between species and
P-element phylogenies. The canonical P-element subfamily, which represents
the active, autonomous transposable element, is restricted to D.
melanogaster. Thus, its origin clearly lies outside of the melanogaster
species group, consistent with the earlier conclusion of recent horizontal
transfer.
相似文献
6.
Carl PC Chen Chih-Chin Hsu Wen-Lin Yeh Hsiu-Chu Lin Sen-Yung Hsieh Shih-Cherng Lin Tai-Tzung Chen Max JL Chen Simon FT Tang 《Proteome science》2011,9(1):1-10
Background
Prenatal screening for Down Syndrome (DS) would benefit from an increased number of biomarkers to improve sensitivity and specificity. Improving sensitivity and specificity would decrease the need for potentially risky invasive diagnostic procedures.Results
We have performed an in depth two-dimensional difference gel electrophoresis (2D DIGE) study to identify potential biomarkers. We have used maternal plasma samples obtained from first and second trimesters from mothers carrying DS affected fetuses compared with mothers carrying normal fetuses. Plasma samples were albumin/IgG depleted and expanded pH ranges of pH 4.5 - 5.5, pH 5.3 - 6.5 and pH 6 - 9 were used for two-dimensional gel electrophoresis (2DE). We found no differentially expressed proteins in the first trimester between the two groups. Significant up-regulation of ceruloplasmin, inter-alpha-trypsin inhibitor heavy chain H4, complement proteins C1s subcomponent, C4-A, C5, and C9 and kininogen 1 were detected in the second trimester in maternal plasma samples where a DS affected fetus was being carried. However, ceruloplasmin could not be confirmed as being consistently up-regulated in DS affected pregnancies by Western blotting.Conclusions
Despite the in depth 2DE approach used in this study the results underline the deficiencies of gel-based proteomics for detection of plasma biomarkers. Gel-free approaches may be more productive to increase the number of plasma biomarkers for DS for non-invasive prenatal screening and diagnosis. 相似文献7.
Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages 总被引:4,自引:0,他引:4
The host-lysis-inducing functions of phi X174 protein E and MS2 protein L
were recently shown to reside on the N-terminal and C-terminal halves of
the two respective lysis proteins. In the present study it is shown that
the small lysis proteins encoded in various colicinogenic plasmids share
local sequence similarities and certain structural characteristics with the
essential peptides of their coliphage-coded counterparts. Despite their
dissimilar sizes and origins, it is suggested that the colicinogenic lysis
proteins are functionally analogous and evolutionarily related to those of
icosahedral single- stranded DNA and RNA phages.
相似文献
8.
Oxalate decarboxylase is a manganese-dependent enzyme that catalyzes the conversion of oxalate to formate and carbon dioxide. We have determined the structure of oxalate decarboxylase from Bacillus subtilis at 1.75 A resolution in the presence of formate. The structure reveals a hexamer with 32-point symmetry in which each monomer belongs to the cupin family of proteins. Oxalate decarboxylase is further classified as a bicupin because it contains two cupin folds, possibly resulting from gene duplication. Each oxalate decarboxylase cupin domain contains one manganese binding site. Each of the oxalate decarboxylase domains is structurally similar to oxalate oxidase, which catalyzes the manganese-dependent oxidative decarboxylation of oxalate to carbon dioxide and hydrogen peroxide. Amino acid side chains in the two metal binding sites of oxalate decarboxylase and the metal binding site of oxalate oxidase are very similar. Four manganese binding residues (three histidines and one glutamate) are conserved as well as a number of hydrophobic residues. The most notable difference is the presence of Glu333 in the metal binding site of the second cupin domain of oxalate decarboxylase. We postulate that this domain is responsible for the decarboxylase activity and that Glu333 serves as a proton donor in the production of formate. Mutation of Glu333 to alanine reduces the catalytic activity by a factor of 25. The function of the other domain in oxalate decarboxylase is not yet known. 相似文献
9.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
10.
Nina M. van Sorge Federico C. Beasley Ivan Gusarov David J. Gonzalez Maren von K?ckritz-Blickwede Sabina Anik Andrew W. Borkowski Pieter C. Dorrestein Evgeny Nudler Victor Nizet 《The Journal of biological chemistry》2013,288(9):6417-6426
Staphylococcus aureus infections present an enormous global health concern complicated by an alarming increase in antibiotic resistance. S. aureus is among the few bacterial species that express nitric-oxide synthase (bNOS) and thus can catalyze NO production from l-arginine. Here we generate an isogenic bNOS-deficient mutant in the epidemic community-acquired methicillin-resistant S. aureus (MRSA) USA300 clone to study its contribution to virulence and antibiotic susceptibility. Loss of bNOS increased MRSA susceptibility to reactive oxygen species and host cathelicidin antimicrobial peptides, which correlated with increased MRSA killing by human neutrophils and within neutrophil extracellular traps. bNOS also promoted resistance to the pharmaceutical antibiotics that act on the cell envelope such as vancomycin and daptomycin. Surprisingly, bNOS-deficient strains gained resistance to aminoglycosides, suggesting that the role of bNOS in antibiotic susceptibility is more complex than previously observed in Bacillus species. Finally, the MRSA bNOS mutant showed reduced virulence with decreased survival and smaller abscess generation in a mouse subcutaneous infection model. Together, these data indicate that bNOS contributes to MRSA innate immune and antibiotic resistance phenotypes. Future development of specific bNOS inhibitors could be an attractive option to simultaneously reduce MRSA pathology and enhance its susceptibility to commonly used antibiotics. 相似文献