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排序方式: 共有174条查询结果,搜索用时 15 毫秒
101.
Human subgingival plaque biofilms are highly complex microbial ecosystems that may depend on H(2)-metabolizing processes. Here we investigated the ubiquity and proportions of methanogenic archaea, sulfate reducers, and acetogens in plaque samples from 102 periodontitis patients. In contrast to the case for 65 healthy control subjects, hydrogenotrophic groups were almost consistently detected in periodontal pockets, with the proportions of methanogens and sulfate reducers being significantly elevated in severe cases. In addition, antagonistic interactions among the three microbial groups indicated that they may function as alternative syntrophic partners of secondary fermenting periodontal pathogens. 相似文献
102.
Mi L Xiao Z Hood BL Dakshanamurthy S Wang X Govind S Conrads TP Veenstra TD Chung FL 《The Journal of biological chemistry》2008,283(32):22136-22146
Isothiocyanates (ITCs) found in cruciferous vegetables, including benzyl-ITC (BITC), phenethyl-ITC (PEITC), and sulforaphane (SFN), inhibit carcinogenesis in animal models and induce apoptosis and cell cycle arrest in various cell types. The biochemical mechanisms of cell growth inhibition by ITCs are not fully understood. Our recent study showed that ITC binding to intracellular proteins may be an important initiating event for the induction of apoptosis. However, the specific protein target(s) and molecular mechanisms were not identified. In this study, two-dimensional gel electrophoresis of human lung cancer A549 cells treated with radiolabeled PEITC and SFN revealed that tubulin may be a major in vivo binding target for ITC. We examined whether binding to tubulin by ITCs could lead to cell growth arrest. The proliferation of A549 cells was significantly reduced by ITCs, with relative activities of BITC > PEITC > SFN. All three ITCs also induced mitotic arrest and apoptosis with the same order of activity. We found that ITCs disrupted microtubule polymerization in vitro and in vivo with the same order of potency. Mass spectrometry demonstrated that cysteines in tubulin were covalently modified by ITCs. Ellman assay results indicated that the modification levels follow the same order, BITC > PEITC > SFN. Together, these results support the notion that tubulin is a target of ITCs and that ITC-tubulin interaction can lead to downstream growth inhibition. This is the first study directly linking tubulin-ITC adduct formation to cell growth inhibition. 相似文献
103.
JAN E. JANEČKA LON I. GRASSMAN JR. RODNEY L. HONEYCUTT MICHAEL E. TEWES 《The Journal of wildlife management》2007,71(4):1357-1360
Abstract: We describe a method for rapidly amplifying whole genomes via a Phi29 DNA polymerase-mediated strand displacement reaction (SDR). Genomic amplification products derived from the SDR reaction resulted in high quantities of DNA suitable for polymerase chain reaction (PCR) amplification and sequencing of mitochondrial genomes. Control region sequences of DNA derived directly from PCR amplicons of extracted DNA were identical to those derived from PCR amplification of SDR genomic DNA. Effective SDR amplification and subsequent sequencing was successful across tissues sources ranging in age from 1 year to 19 years. Strand replacement reaction genomic amplification offers a means of obtaining large quantities of DNA from small amounts of tissue. 相似文献
104.
The objective of the study was to examine salivary biomarker response to fluid consumption in exercising athletes. Exercise induces stress on the body and salivary alpha amylase (sAA) and salivary cortisol are useful biomarkers for activity in the sympathoadrenal medullary system and the hypothalamic pituitary adrenal axis which are involved in the stress response. Fifteen college students were given 150 ml and 500 ml of water on different days and blinded to fluid condition. The exercise protocol was identical for both fluid conditions using absolute exercise intensities ranging from moderate to high. Saliva was collected prior to exercise, post moderate and post high intensities and analyzed by Salimetrics assays. Exercise was significant for sAA with values different between pre-exercise (85 ± 10 U · ml−1) and high intensity (284 ± 30 U · ml−1) as well as between moderate intensity (204 ± 32 U · ml−1) and high intensity. There was no difference in sAA values between fluid conditions at either intensity. Exercise intensity and fluid condition were each significant for cortisol. Cortisol values were different between pre-exercise (0.30 ± 0.03 ug · dL−1) and high intensity (0.45 ± 0.05 ug · dL−1) as well as between moderate intensity (0.33 ± 0.04 ug · dL−1) and high intensity. Moderate exercise intensity cortisol was lower in the 500 ml condition (0.33 ± 0.03 ug · dL−1) compared with the 150 ml condition (0.38 ± 0.03 ug · dL−1). This altered physiological response due to fluid consumption could influence sport performance and should be considered. In addition, future sport and exercise studies should control for fluid consumption. 相似文献
105.
106.
107.
Conrads G Citron DM Mutters R Jang S Goldstein EJ 《Systematic and applied microbiology》2004,27(4):407-413
Fourteen strains of Gram-negative, anaerobic, fluoroquinolone-resistant, non-sporulating rods were isolated from various infections in cats and dogs, as well as from wounds in humans after cat- or dog-bites. These strains were characterized by sequencing of the 16S-23S rDNA internal transcribed spacer (ITS) regions, 16S rDNA, DNA-DNA hybridization, phylogenetic analysis, and phenotypic tests. The results indicate that the novel strains belong to a distinct species, closely related to Fusobacterium nucleatum. The species Fusobacterium canifelinum sp. nov. is proposed, with strain ATCC BAA 689T as the type strain. 相似文献
108.
An accurate mass tag strategy for quantitative and high-throughput proteome measurements 总被引:1,自引:0,他引:1
Smith RD Anderson GA Lipton MS Pasa-Tolic L Shen Y Conrads TP Veenstra TD Udseth HR 《Proteomics》2002,2(5):513-523
We describe and demonstrate a global strategy that extends the sensitivity, dynamic range, comprehensiveness, and throughput of proteomic measurements based upon the use of peptide "accurate mass tags" (AMTs) produced by global protein enzymatic digestion. The two-stage strategy exploits Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry to validate peptide AMTs for a specific organism, tissue or cell type from "potential mass tags" identified using conventional tandem mass spectrometry (MS/MS) methods, providing greater confidence in identifications as well as the basis for subsequent measurements without the need for MS/MS, and thus with greater sensitivity and increased throughput. A single high resolution capillary liquid chromatography separation combined with high sensitivity, high resolution and accurate FT-ICR measurements has been shown capable of characterizing peptide mixtures of significantly more than 10(5) components with mass accuracies of < 1 ppm, sufficient for broad protein identification using AMTs. Other attractions of the approach include the broad and relatively unbiased proteome coverage, the capability for exploiting stable isotope labeling methods to realize high precision for relative protein abundance measurements, and the projected potential for study of mammalian proteomes when combined with additional sample fractionation. Using this strategy, in our first application we have been able to identify AMTs for >60% of the potentially expressed proteins in the organism Deinococcus radiodurans. 相似文献
109.
Walter RB; Rolig RL; Kozak KA; McEntire B; Morizot DC; Nairn RS 《Molecular biology and evolution》1993,10(6):1227-1238
Fishes represent the stem vertebrate condition and have maintained several
gene arrangements common to mammalian genomes throughout the 450 Myr of
divergence from a common ancestor. One such syntenic arrangement includes
the GPI-PEPD enzyme association on Xiphophorus linkage group IV and human
chromosome 19. Previously we assigned the Xiphophorus homologue of the
human ERCC2 gene to linkage group U5 in tight association with the CKM
locus. CKM is also tightly linked to the ERCC2 locus on human chromosome
19, leading to speculation that human chromosome 19 may have arisen by
fusion of two ancestral linkage groups which have been maintained in
fishes. To investigate this hypothesis further, we isolated and sequenced
Xiphophorus fish genomic regions exhibiting considerable sequence
similarity to the human DNA ligase 1 amino acid sequence. Comparison of the
fish DNA ligase sequence with those of other species suggests several modes
of amino acid conservation in this gene. A 2.2-kb restriction fragment
containing part of an X. maculatus DNA ligase 1 exon was used in backcross
hybrid mapping with 12 enzyme or RFLP loci. Significant linkage was
observed between the nucleoside phosphorylase (NP2) and the DNA ligase
(LIG1) loci on Xiphophorus linkage group VI. This assignment suggests that
the association of four DNA repair-related genes on human chromosome 19 may
be the result of chance chromosomal rearrangements.
相似文献
110.
Angstrom J; Teneberg S; Milh MA; Larsson T; Leonardsson I; Olsson BM; Halvarsson MO; Danielsson D; N aslund I; Ljungh A; Wadstrom T; Karlsson KA 《Glycobiology》1998,8(4):297-309
The possible role of glycosphingolipids as adhesion receptors for the human
gastric pathogen Helicobacter pylori was examined by use of radiolabeled
bacteria, or protein extracts from the bacterial cell surface, in the
thin-layer chromatogram binding assay. Of several binding specificities
found, the binding to lactosylceramide is described in detail here, the
others being reported elsewhere. By autoradiography a preferential binding
to lactosylceramide having sphingosine/phytosphingosine and 2-D hydroxy
fatty acids was detected, whereas lactosylceramide having sphingosine and
nonhydroxy fatty acids was consistently nonbinding. A selective binding of
H. pylori to lactosylceramide with phytosphingosine and 2-D hydroxy fatty
acid was obtained when the different lactosylceramide species were
incorporated into liposomes, but only in the presence of cholesterol,
suggesting that this selectivity may be present also in vivo . Importantly,
lactosylceramide with sphingosine and hydroxy fatty acids does not bind in
this assay. Furthermore, a lactosylceramide-based binding pattern obtained
for different trisaccharide glycosphingolipids is consistent with the
assumption that this selectivity is due to binding of a conformation of
lactosylceramide in which the oxygen of the 2-D fatty acid hydroxyl group
forms a hydrogen bond with the Glc hydroxy methyl group, yielding an
epitope presentation different from other possible conformers. An
alternative conformation that may come into consideration corresponds to
the crystal structure found for cerebroside, in which the fatty acid
hydroxyl group is free to interact directly with the adhesin. By isolating
glycosphingolipids from epithelial cells of human stomach from seven
individuals, a binding of H.pylori to the diglycosylceramide region of the
non-acid fraction could be demonstrated in one of these cases. Mass
spectrometry showed that the binding-active sample contained
diglycosylceramides with phytosphingosine and 2-D hydroxy fatty acids with
16-24 carbon atoms in agreement with the results related above.
相似文献