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71.
Sarfraz A Tunio Neil J Oldfield Dlawer AA Ala'Aldeen Karl G Wooldridge David PJ Turner 《BMC microbiology》2010,10(1):280
Background
Glyceraldehyde 3-phosphate dehydrogenases (GAPDHs) are cytoplasmic glycolytic enzymes, which although lacking identifiable secretion signals, have also been found localized to the surface of several bacteria (and some eukaryotic organisms); where in some cases they have been shown to contribute to the colonization and invasion of host tissues. Neisseria meningitidis is an obligate human nasopharyngeal commensal which can cause life-threatening infections including septicaemia and meningitis. N. meningitidis has two genes, gapA-1 and gapA-2, encoding GAPDH enzymes. GapA-1 has previously been shown to be up-regulated on bacterial contact with host epithelial cells and is accessible to antibodies on the surface of capsule-permeabilized meningococcal cells. The aims of this study were: 1) to determine whether GapA-1 was expressed across different strains of N. meningitidis; 2) to determine whether GapA-1 surface accessibility to antibodies was dependant on the presence of capsule; 3) to determine whether GapA-1 can influence the interaction of meningococci and host cells, particularly in the key stages of adhesion and invasion. 相似文献72.
73.
The complete mitochondrial DNA sequence of the shark Mustelus manazo: evaluating rooting contradictions to living bony vertebrates 总被引:5,自引:0,他引:5
A remarkable example of a misleading mitochondrial protein tree is
presented, involving ray-finned fishes, coelacanths, lungfishes, and
tetrapods, with sea lampreys as an outgroup. In previous molecular
phylogenetic studies on the origin of tetrapods, ray-finned fishes have
been assumed as an outgroup to the tetrapod/lungfish/coelacanth clade, an
assumption supported by morphological evidence. Standard methods of
molecular phylogenetics applied to the protein-encoding genes of
mitochondria, however, give a bizarre tree in which lamprey groups with
lungfish and, therefore, ray-finned fishes are not the outgroup to a
tetrapod/lungfish/coelacanth clade. All of the dozens of published
phylogenetic methods, including every possible modification to maximum
likelihood known to us (such as inclusion of site heterogeneity and
exclusion of potentially misleading hydrophobic amino acids), fail to place
the ray-finned fishes in a biologically acceptable position. A likely cause
of this failure may be the use of an inappropriate outgroup. Accordingly,
we have determined the complete mitochondrial DNA sequence from the shark,
Mustelus manazo, which we have used as an alternative and more proximal
outgroup than the lamprey. Using sharks as the outgroup, lungfish appear to
be the closest living relative of tetrapods, although the possibility of a
lungfish/coelacanth clade being the sister group of tetrapods cannot be
excluded.
相似文献
74.
Decomposable graphical Gaussian model determination 总被引:8,自引:0,他引:8