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301.
Cytosolic isocitrate dehydrogenase in humans, mice, and voles and phylogenetic analysis of the enzyme family 总被引:3,自引:0,他引:3
Nekrutenko A; Hillis DM; Patton JC; Bradley RD; Baker RJ 《Molecular biology and evolution》1998,15(12):1674-1684
In this study, we report cDNA sequences of the cytosolic NADP-dependent
isocitrate dehydrogenase for humans, mice, and two species of voles
(Microtus mexicanus and Microtus ochrogaster). Inferred amino acid
sequences from these taxa display a high level of amino acid sequence
conservation, comparable to that of myosin beta heavy chain, and share
known structural features. A Caenorhabditis elegans enzyme that was
previously identified as a protein similar to isocitrate dehydrogenase is
most likely the NADP-dependent cytosolic isocitrate dehydrogenase enzyme
equivalent, based on amino acid similarity to mammalian enzymes and
phylogenetic analysis. We also suggest that NADP-dependent isocitrate
dehydrogenases characterized from alfalfa, soybean, and eucalyptus are most
likely cytosolic enzymes. The phylogenetic tree of various isocitrate
dehydrogenases from eukaryotic sources revealed that independent gene
duplications may have given rise to the cytosolic and mitochondrial forms
of NADP-dependent isocitrate dehydrogenase in animals and fungi. There
appears to be no statistical support for a hypothesis that the
mitochondrial and cytosolic forms of the enzyme are orthologous in these
groups. A possible scenario of the evolution of NADP-dependent isocitrate
dehydrogenases is proposed.
相似文献
302.
Phylogenetic utility of elongation factor-1 alpha in noctuoidea (Insecta: Lepidoptera): the limits of synonymous substitution 总被引:1,自引:1,他引:1
Mitchell A; Cho S; Regier JC; Mitter C; Poole RW; Matthews M 《Molecular biology and evolution》1997,14(4):381-390
To test its phylogenetic utility, nucleotide sequence variation in a
1,240-bp fragment of the elongation factor-1 alpha (EF-1 alpha) gene was
examined in 49 moth species representing the major groups of the
superfamily Noctuoidea. Both parsimony and distance analyses supported the
monophyly of nearly all groups for which there are clear morphological
synapomorphies. Clades of subfamily rank and lower, probably mid-Tertiary
and younger, were strongly supported. The third codon position contains 88%
of variable sites, and approaches saturation at approximately 20% sequence
divergence, possibly due to among-site rate heterogeneity and composition
bias; higher divergences occur only in association with shifts in
composition. Surprisingly, the few nonsynonymous changes appear no more
phylogenetically reliable than synonymous changes. Signal strength for
basal divergences is weak and fails to improve with character weighting;
thus, dense taxon sampling is probably needed for strong inference from
EF-1 alpha regarding deeper splits in Noctuoidea (probably early Tertiary).
EF-1 alpha synonymous changes show promise for phylogeny reconstruction
within Noctuidae and other groups of Tertiary age.
相似文献
303.
Abstract The McMurdo Dry Valley lakes, Antarctica, one of the Earth's southernmost ecosystems containing liquid water, harbor some of the most environmentally extreme (cold, nutrient-deprived) conditions on the planet. Lake Bonney has a permanent ice cover that supports a unique microbial habitat, provided by soil particles blown onto the lake surface from the surrounding, ice-free valley floor. During continuous sunlight summers (Nov.-Feb.), the dark soil particles are heated by solar radiation and melt their way into the ice matrix. Layers and patches of aggregates and liquid water are formed. Aggregates contain a complex cyanobacterial-bacterial community, concurrently conducting photosynthesis (CO2 fixation), nitrogen (N2) fixation, decomposition, and biogeochemical zonation needed to complete essential nutrient cycles. Aggregate-associated CO2- and N2-fixation rates were low and confined to liquid water (i.e., no detectable activities in the ice phase). CO2 fixation was mediated by cyanobacteria; both cyanobacteria and eubacteria appeared responsible for N2 fixation. CO2 fixation was stimulated primarily by nitrogen (NO3-), but also by phosphorus (PO43-). PO43- and iron (FeCl3 + EDTA) enrichment stimulated of N2 fixation. Microautoradiographic and physiological studies indicate a morphologically and metabolically diverse microbial community, exhibiting different cell-specific photosynthetic and heterotrophic activities. The microbial community is involved in physical (particle aggregation) and chemical (establishing redox gradients) modification of a nutrient- and organic matter-enriched microbial "oasis," embedded in the desertlike (i.e., nutrient depleted) lake ice cover. Aggregate-associated production and nutrient cycling represent microbial self-sustenance in a microenvironment supporting "life at the edge," as it is known on Earth. 相似文献
304.
Posner GH Kim HJ Kahraman M Jeon HB Suh BC Li H Dolan P Kensler TW 《Bioorganic & medicinal chemistry》2005,13(19):5569-5580
A series 2a-4b of seven new side-chain ketone analogs of calcitriol (1) have been prepared. Unexpectedly, several of these 24- and 25-tert-butyl ketones, even though lacking the classical side-chain tertiary hydroxyl group, are considerably more antiproliferative in vitro than the hormone calcitriol (1) even at physiologically relevant low nanomolar concentrations and are less calcemic than calcitriol (1) in vivo. In addition, ketone analog 19-nor-2a is not significantly less calcemic in vivo than 19-methylene analog 2a. 相似文献
305.
Gutierrez A del Rio JC Martinez MJ Martinez AT 《Applied and environmental microbiology》1999,65(4):1367-1371
Solid-state fermentation of eucalypt wood with several fungal strains was investigated as a possible biological pretreatment for decreasing the content of compounds responsible for pitch deposition during Cl2-free manufacture of paper pulp. First, different pitch deposits were characterized by gas chromatography (GC) and GC-mass spectrometry (MS). The chemical species identified arose from lipophilic wood extractives that survived the pulping and bleaching processes. Second, a detailed GC-MS analysis of the lipophilic fraction after fungal treatment of wood was carried out, and different degradation patterns were observed. The results showed that some basidiomycetes that decreased the lipophilic fraction also released significant amounts of polar extractives, which were identified by thermochemolysis as originating from lignin depolymerization. Therefore, the abilities of fungi to control pitch should be evaluated after analysis of compounds involved in deposit formation and not simply by estimating the decrease in the total extractive content. In this way, Phlebia radiata, Funalia trogii, Bjerkandera adusta, and Poria subvermispora strains were identified as the most promising organisms for pitch biocontrol, since they degraded 75 to 100% of both free and esterified sterols, as well as other lipophilic components of the eucalypt wood extractives. Ophiostoma piliferum, a fungus used commercially for pitch control, hydrolyzed the sterol esters and triglycerides, but it did not appear to be suitable for eucalypt wood treatment because it increased the content of free sitosterol, a major compound in pitch deposits. 相似文献
306.
There is now abundant evidence that the intracellular concentration of the EGFR and many other receptors for peptide hormones and growth factors is important for the temporal and spatial regulation of cell signaling. Spatial control is achieved by the selective compartmentalization of signaling components into endosomes. However further control may be effected by sequestration into sub‐domains within a given organelle such as membrane rafts which are dynamic, nano scale structures rich in cholesterol and sphingolipids. Current data suggest the presence of EGFRs in non‐caveolae membrane rafts. High doses of EGF seem to promote the sorting of EGFR to late endosomes through a raft/cholesterol dependant mechanism, implicating them in EGFR degradation. However our work and that of others has led us to propose a model in which membrane rafts in late endosomes sequester highly active EGFR leading to the recruitment and activation of MAPK in this compartment. J. Cell. Biochem. 109: 1103–1108, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
307.
Charles D Criscione Claudia LL Valentim Hirohisa Hirai Philip T LoVerde Timothy JC Anderson 《Genome biology》2009,10(6):R71-13
Background
Schistosoma mansoni is a blood fluke that infects approximately 90 million people. The complete life cycle of this parasite can be maintained in the laboratory, making this one of the few experimentally tractable human helminth infections, and a rich literature reveals heritable variation in important biomedical traits such as virulence, host-specificity, transmission and drug resistance. However, there is a current lack of tools needed to study S. mansoni's molecular, quantitative, and population genetics. Our goal was to construct a genetic linkage map for S. mansoni, and thus provide a new resource that will help stimulate research on this neglected pathogen. 相似文献308.
309.
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