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911.
Green Fluorescent Protein Labeling Escherichia coli TG1 Confirms Intestinal Bacterial Translocation in a Rat Model of Chemotherapy 总被引:3,自引:0,他引:3
It has been reported that treatment with methotrexate (MTX) induces intestinal bacterial translocation; however, the definitive
evidence of intestinal bacterial translocation induced by MTX has been lacking. The aim of this study was to confirm the intestinal
bacterial translocation caused by MTX and to evaluate the preventive effect of granulocyte colony-stimulating factor (G-CSF)
on intestinal bacterial translocation caused by MTX. Sprague-Dawley rats were treated with MTX (3.5 mg/kg) for 3 days to induce
intestinal bacterial translocation; with gavaged Escherichia coli TG1 labeled with green fluorescent protein (GFP) for 2 days to track intestinal bacterial translocation; and with G-CSF (10 μg/kg)
for 4 days to prevent intestinal bacterial translocation. Representative tissue specimens from the mesenteric lymph nodes,
spleen, liver, and kidney were aseptically harvested for bacteria culture in ampicillin-supplemented medium. The bacteria
labeled with GFP were detected in tissue specimens harvested from the rats treated with MTX but not detected in the rats that
were not treated with MTX. G-CSF significantly ameliorated the situation of intestinal bacterial translocation. 相似文献
912.
Identification of differentially expressed genes in seeds of two near-isogenic Brassica napus lines with different oil content 总被引:5,自引:0,他引:5
The regulation of seed oil synthesis in rapeseed is largely unknown. In this study, we compared the gene expression during seed development between two lines of Brassica napus with a 10% difference in oil content. We isolated the immature seeds 15 and 25 days after flowering at periods preceding and including the major accumulation of storage oils and proteins. The differentially expressed gene clones between the two rape lines were isolated by subtractive suppression hybridization (SSH). All SSH clones were arrayed and screened by dot blot hybridization, followed by RT-PCR analysis for selected clones. A total of 217 cDNA clones corresponding to 30 genes were found to have a high expression in seeds with high oil content. Six genes were highly expressed in seeds with low oil content. Northern blot and enzyme activity analysis demonstrated a change in expression pattern of several genes. The results provide information on gene-encoding factors responsible for the regulation of oil synthesis. The possible role of these genes in seeds is discussed. The genes in this study may be suitable as novel targets for genetic improvement of seed oil content and may also provide molecular markers for studies of rape breeding. 相似文献
913.
Significance of organic nitrogen acquisition for dominant plant species in an alpine meadow on the Tibet plateau, China 总被引:4,自引:0,他引:4
Xingliang Xu Hua Ouyang Yakov Kuzyakov Andreas Richter Wolfgang Wanek 《Plant and Soil》2006,285(1-2):221-231
Though the potential of plants to take up organic N (e.g., amino acids) is well established, the true significance of organic N acquisition to plant N nutrition has not yet been quantified under field conditions. Here we demonstrate that organic N contributes significantly to the annual N uptake of three dominant plant species (Kobresia humilis, Saussurea superba and Stipa aliena) of alpine meadows on the Tibet Plateau, China. This was achieved by using double-labelled (14C and 15N) algae as a source for slow and continuous release of amino acids, and tracing both labels in the above- and below-ground plant biomass. Four months after addition of algae, between 0.5% and 2.6% of 14C and 5% and 14% of 15N from added algae were recovered in the plants, which translate into an uptake of organic N between 0.3 mg N m−2 and 1.5 mg N m−2. The calculated contribution of organic N to total N uptake was estimated to range between 21% and 35% for K. humilis, and between 13% and 21% for S. aliena and S. superba, respectively, implying that organic N uptake by grassland plants is quantitatively significant under field conditions in the studied alpine meadows. This finding has important ecological implications with regard to competition for organic N between microorganisms and plant roots. 相似文献
914.
915.
We studied the structures of the cerebellar cortex of young adult and old cats for age-related changes, which were statistically
analysed. Nissl staining was used to visualize the cortical neurons. The immunohistochemical method was used to display glial
fibrillary acidic protein (GFAP)-immunoreactive (IR) astrocytes and neurofilament-immunoreactive (NF-IR) neurons. Under the
microscope, the thickness of the cerebellar cortex was measured; and the density of neurons in all the layers as well as that
of GFAP-IR cells in the granular layer was analysed. Compared with young adult cats, the thickness of the molecular layer
and total cerebellar cortex was significantly decreased in old cats, and that of the granular layer increased. The density
of neurons in each layer was significantly lower in old cats than in young adult ones. Astrocytes in old cats were significantly
denser than in young adult ones, and accompanied by evident hypertrophy of the cell bodies and enhanced immunoreaction of
GFAP substance. Purkinje cells (PCs) in old cats showed much fewer NF-IR dendrites than those in young adults. The above findings
indicate a loss of neurons and decrease in the number of dendrites of the PCs in the aged cerebellar cortex, which might underlie
the functional decline of afferent efficacy and information integration in the senescent cerebellum. An age-dependent enhancement
of activity of the astrocytes may exert a protective effect on neurons in the aged cerebellum 相似文献
916.
Histone deacetylase 6 (HDAC6) is the only known HDAC with two potentially functional catalytic domains, yet the role towards substrate played by these two domains remains ambiguous. Most studies report HDAC6 activities measured using either immune complexes or in vitro translated products. Here, we characterize the activity of highly purified recombinant HDAC6, mutants with active site histidine mutations in each domain (H216A and H611A), and individual catalytic domains. The deacetylase activities of these proteins, as well as their kinetic parameters, were measured using histone, alpha-tubulin, and fluorogenic acetylated lysine as substrates. Mutant H216A only slightly lowers the catalytic rate. However, mutant H611A decreases the catalytic rate more than 5000-fold. The first domain expressed alone is not catalytically active. In contrast, the second domain shows only a modest decrease in substrate binding and product formation rate. Our results indicate that the in vitro deacetylase activity of HDAC6 resides in the C-terminal second catalytic domain. 相似文献
917.
With the high-resolution variable-pressure NMR spectroscopy, one can study conformational fluctuations of proteins in a much wider conformational space than hitherto explored by NMR and other spectroscopic techniques. This is because a protein in solution generally exists as a dynamic mixture of conformers mutually differing in partial molar volume, and pressure can select the population of a conformer according to its relative volume. In this review, we describe how variable-pressure NMR can be used to probe conformational fluctuations of proteins in a wide conformational space from the folded to the fully unfolded structures, with actual examples. Furthermore, the newly emerging technique "NMR snapshots" expresses amply fluctuating protein structures as changes in atomic coordinates. Finally, the concept of conformational fluctuation is extended to include intermolecular association leading to amyloidosis. 相似文献
918.
Distinct roles of CysLT1 and CysLT2 receptors in oxygen glucose deprivation-induced PC12 cell death 总被引:6,自引:0,他引:6
Sheng WW Li CT Zhang WP Yuan YM Hu H Fang SH Zhang L Wei EQ 《Biochemical and biophysical research communications》2006,346(1):19-25
Cysteinyl leukotrienes are involved in ischemic brain injury, and their receptors (CysLT(1) and CysLT(2)) have been cloned. To clarify which subtype mediates the ischemic neuronal injury, we performed permanent transfection to increase CysLT(1) and CysLT(2) receptor expressions in PC12 cells. Oxygen glucose deprivation (OGD)-induced cell death was detected by Hoechst 33258 and propidium iodide fluorescent staining as well as by flow cytometry. OGD induced late phase apoptosis mainly and necrosis minimally. Over-expression of CysLT(1) receptor decreased and over-expression of CysLT(2) receptor increased OGD-induced cell death. An agonist LTD(4) (10(-7)M) also induced apoptosis, especially in CysLT(2) receptor over-expressing cells. A selective CysLT(1) receptor antagonist montelukast did not affect OGD-induced apoptosis; while non-selective CysLT receptor antagonist Bay u9773 inhibited OGD-induced apoptosis, especially in CysLT(2) receptor over-expressing cells. Thus, CysLT(1) and CysLT(2) receptors play distinct roles in OGD-induced PC12 cell death; CysLT(1) attenuates while CysLT(2) facilitates the cell death. 相似文献
919.
920.