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121.
Sharon M Tennant Marija Tauschek Kristy Azzopardi Andrea Bigham Vicki Bennett-Wood Elizabeth L Hartland Weihong Qi Thomas S Whittam Roy M Robins-Browne 《BMC microbiology》2009,9(1):117-11
Background
Enteropathogenic E. coli (EPEC) is a prominent cause of diarrhoea, and is characterised in part by its carriage of a pathogeniCity island: the locus for enterocyte effacement (LEE). EPEC is divided into two subtypes according to the presence of bundle-forming pili (BFP), a fimbrial adhesin that is a virulence determinant of typical EPEC (tEPEC), but is absent from atypical EPEC (aEPEC). Because aEPEC lack BFP, their virulence has been questioned, as they may represent LEE-positive Shiga toxin-producing E. coli (STEC) that have lost the toxin-encoding prophage, or tEPEC that have lost the genes for BFP. To determine if aEPEC isolated from humans in Australia or New Zealand fall into either of these categories, we undertook phylogenetic analysis of 75 aEPEC strains, and compared them with reference strains of EPEC and STEC. We also used PCR and DNA hybridisation to determine if aEPEC carry virulence determinants that could compensate for their lack of BFP. 相似文献122.
Spitsbergen JM Blazer VS Bowser PR Cheng KC Cooper KR Cooper TK Frasca S Groman DB Harper CM Law JM Marty GD Smolowitz RM St Leger J Wolf DC Wolf JC 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2009,149(2):249-257
Utilization of finfish and aquatic invertebrates in biomedical research and as environmental sentinels has grown dramatically in recent decades. Likewise the aquaculture of finfish and invertebrates has expanded rapidly worldwide as populations of some aquatic food species and threatened or endangered aquatic species have plummeted due to overharvesting or habitat degradation. This increasing intensive culture and use of aquatic species has heightened the importance of maintaining a sophisticated understanding of pathology of various organ systems of these diverse species. Yet, except for selected species long cultivated in aquaculture, pathology databases and the workforce of highly trained pathologists lag behind those available for most laboratory animals and domestic mammalian and avian species. Several factors must change to maximize the use, understanding, and protection of important aquatic species: 1) improvements in databases of abnormalities across species; 2) standardization of diagnostic criteria for proliferative and nonproliferative lesions; and 3) more uniform and rigorous training in aquatic morphologic pathology. 相似文献
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125.
Choi HS Wang Z Richmond W He X Yang K Jiang T Sim T Karanewsky D Gu XJ Zhou V Liu Y Ohmori O Caldwell J Gray N He Y 《Bioorganic & medicinal chemistry letters》2006,16(8):2173-2176
A series of 2-amino-9-aryl-7H-pyrrolo[2,3-d]pyrimidines were designed and synthesized to target focal adhesion kinase (FAK). A number of these pyrrolopyrimides exhibited low micromolar inhibitory activities against focal adhesion kinase, and their preliminary SAR was established via systematic chemical modifications. The 2-amino-9-aryl-7H-pyrrolo[2,3-d]pyrimidines represent a new class of kinase inhibitors. 相似文献
126.
Shue HJ Chen X Schwerdt JH Paliwal S Blythin DJ Lin L Gu D Wang C Reichard GA Wang H Piwinski JJ Duffy RA Lachowicz JE Coffin VL Nomeir AA Morgan CA Varty GB Shih NY 《Bioorganic & medicinal chemistry letters》2006,16(4):1065-1069
A series of novel five-membered urea derivatives as potent NK1 receptor antagonists is described. The effects of substitution of a 4-fluoro group at the phenyl ring and the introduction of an alpha-methyl group at the benzylic position to improve potency and duration of in vivo activity are discussed. Several compounds with high affinity and sustained in vivo activity were identified. 相似文献
127.
Deville K Gold VA Robson A Whitehouse S Sessions RB Baldwin SA Radford SE Collinson I 《The Journal of biological chemistry》2011,286(6):4659-4669
Protein secretion in bacteria is driven through the ubiquitous SecYEG complex by the ATPase SecA. The structure of SecYEG alone or as a complex with SecA in detergent reveal a monomeric heterotrimer enclosing a central protein channel, yet in membranes it is dimeric. We have addressed the functional significance of the oligomeric status of SecYEG in protein translocation using single molecule and ensemble methods. The results show that while monomers are sufficient for the SecA- and ATP-dependent association of SecYEG with pre-protein, active transport requires SecYEG dimers arranged in the back-to-back conformation. Molecular modeling of this dimeric structure, in conjunction with the new functional data, provides a rationale for the presence of both active and passive copies of SecYEG in the functional translocon. 相似文献
128.
Ó Cuív P Aguirre de Cárcer D Jones M Klaassens ES Worthley DL Whitehall VL Kang S McSweeney CS Leggett BA Morrison M 《Microbial ecology》2011,61(2):353-362
Potentially valuable sources of DNA have been extracted from human colonic tissues and are retained in biobanks throughout
the world, and might be re-examined to better understand host–microbe interactions in health and disease. However, the published
protocols for DNA extraction typically used by gastroenterologists have not been systematically compared in terms of their
recovery of the microbial fraction associated with colonic tissue. For this reason, we examined how three different tissue
DNA extraction methods (the QIAGEN AllPrep DNA/RNA kit, salting out and high molecular weight (HMW) methods of DNA extraction)
employed in past clinical trials, and the repeated bead beating and column (RBB+C) method might impact the recovery of microbial
DNA from colonic tissue, using a custom designed phylogenetic microarray for gut bacteria and archaea. All four methods produced
very similar profiles of the microbial diversity, but there were some differences in probe signal intensities, with the HMW
method producing stronger probe intensities for a subset of the Firmicutes probes including Clostridium and Streptococcus spp. Real-time PCR analysis revealed that the HMW and RBB+C extracted DNA contained significantly more DNA of Firmicutes
origin and that the different DNA extraction methods also gave variable results in terms of host DNA recovery. All of the
methods tested recovered DNA from the archaeal community although there were some differences in probe signal intensity. Based
on these findings, we conclude that while all four methods are efficacious at releasing microbial DNA from biopsy tissue samples,
the HMW and RBB+C methods of DNA extraction may release more DNA from some of the Firmicutes bacteria associated with colonic
tissue. Thus, DNA archived in biobanks could be suitable for retrospective profiling analyses, provided the caveats with respect
to the DNA extraction method(s) used are taken into account. 相似文献
129.
The bottleneck of JNK signaling: molecular and functional characteristics of MKK4 and MKK7 总被引:1,自引:0,他引:1
The functions of mitogen-activated protein kinases (MKKs) 4 and 7 are typically associated with the c-Jun N-terminal kinase (JNK) signaling pathway. Both MKKs synergistically phosphorylate different JNK isoforms and are therefore involved in numerous physiological (e.g. differentiation and proliferation) and pathological (e.g. apoptosis and tumorigenesis) processes. MKK4 and MKK7 share similar molecular characteristics as well as several upstream activators and scaffold proteins. However, their functions are non-redundant and determined by different stimuli, biochemical interactions and differential tissue distribution. The central question is how two MKKs regulate or affect the multiple actions of their JNK substrates. Similar to JNKs, MKK4 and MKK7 can simultaneously exert divergent functions in different cellular compartments and signalosomes. It is also important to realize that the MKK effects are splice variant-specific. The present review not only summarizes the various modes of MKK4 and MKK7 activation and activity, but also their functions. We also extensively describe their impact on JNK signaling, their molecular interactions resulting in the formation of context-specific signalosomes and the functional consequences of JNK deficiency. 相似文献
130.
Oxidative stress and calcium signaling in the adverse effects of environmental particles (PM10) 总被引:14,自引:0,他引:14
Donaldson K Stone V Borm PJ Jimenez LA Gilmour PS Schins RP Knaapen AM Rahman I Faux SP Brown DM MacNee W 《Free radical biology & medicine》2003,34(11):1369-1382
This review focuses on the potential role that oxidative stress plays in the adverse effects of PM(10). The central hypothesis is that the ability of PM(10) to cause oxidative stress underlies the association between increased exposure to PM(10) and both exacerbations of lung disease and lung cancer. Pulmonary inflammation may also underlie the cardiovascular effects seen following increased PM(10), although the mechanisms of the cardiovascular effects of PM(10) are not well understood. PM(10) is a complex mix of various particle types and several of the components of PM(10) are likely to be involved in the induction of oxidative stress. The most likely of these are transition metals, ultrafine particle surfaces, and organic compounds. In support of this hypothesis, oxidative stress arising from PM(10) has been shown to activate a number of redox-responsive signaling pathways in lung target cells. These pathways are involved in expression of genes that play a role in responses relevant to inflammation and pathological change, including MAPKs, NF-kappaB, AP-1, and histone acetylation. Oxidative stress from particles is also likely to play an important role in the carcinogenic effects associated with PM(10) and hydroxyl radicals from PM(10) cause DNA damage in vitro. 相似文献