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31.
A critical and difficult part of studying cancer with DNA microarrays is data interpretation. Besides the need for data analysis algorithms, integration of additional information about genes might be useful. We performed genome-wide expression profiling of 36 types of normal human tissues and identified 2503 tissue-specific genes. We then systematically studied the expression of these genes in cancers by reanalyzing a large collection of published DNA microarray datasets. We observed that the expression level of liver-specific genes in hepatocellular carcinoma (HCC) correlates with the clinically defined degree of tumor differentiation. Through unsupervised clustering of tissue-specific genes differentially expressed in tumors, we extracted expression patterns that are characteristic of individual cell types, uncovering differences in cell lineage among tumor subtypes. We were able to detect the expression signature of hepatocytes in HCC, neuron cells in medulloblastoma, glia cells in glioma, basal and luminal epithelial cells in breast tumors, and various cell types in lung cancer samples. We also demonstrated that tissue-specific expression signatures are useful in locating the origin of metastatic tumors. Our study shows that integration of each gene's breadth of expression (BOE) in normal tissues is important for biological interpretation of the expression profiles of cancers in terms of tumor differentiation, cell lineage, and metastasis. 相似文献
32.
A dipalmitoylated lipoprotein from Mycoplasma pneumoniae activates NF-kappa B through TLR1, TLR2, and TLR6 总被引:1,自引:0,他引:1
The pathogenesis of Mycoplasma pneumoniae infection is considered to be in part attributed to excessive immune responses. Recently, lipoproteins from mycoplasmas have been reported to induce NF-kappaB activation. In this study, we examined the ability of lipoproteins from M. pneumoniae to activate NF-kappaB, and the active component responsible for the NF-kappaB activation was identified. Lipid-associated membrane proteins from M. pneumoniae were found to induce NF-kappaB through TLR 2 in a human monocytic cell line, THP-1. The active component of the Lipid-associated membrane proteins was a subunit b of F0F1-type ATPase (F0F1-ATPase). The F0F1-ATPase is assumed to contain two palmitic acids. The activation of NF-kappaB by the F0F1-ATPase was inhibited by a dominant negative construct of TLR1 and TLR6. These results indicate that the activation of NF-kappaB by F0F1-ATPase is dependent on TLR1, TLR2, and TLR6. The activity of the F0F1-ATPase was decreased with pretreatment of lipoprotein lipase but not protease, indicating that the lipid moiety of the F0F1-ATPase was important for the NF-kappaB activation. Thus, a dipalmitoylated lipoprotein from M. pneumoniae was found to activate NF-kappaB through TLR1, TLR2, and TLR6. 相似文献
33.
34.
Muramoto Y Ozaki H Takada A Park CH Sunden Y Umemura T Kawaoka Y Matsuda H Kida H 《Microbiology and immunology》2006,50(1):73-81
Severe hemorrhage at multiple organs is frequently observed in chickens infected with highly pathogenic avian influenza (HPAI) A viruses. In this study we examined whether HPAI virus infection leads to coagulation disorder in chickens. Pathological examinations showed that the fibrin thrombi were formed in arterioles at the lung, associated with the viral antigens in endothelial cells of chickens infected intravenously with HPAI virus. Hematological analyses of peripheral blood collected from the chickens revealed that coagulopathy was initiated at early stage of infection when viral antigens were detected only in the endothelial cells and monocytes/macrophages. Furthermore, gene expression of the tissue factor, the main initiator of blood coagulation, was upregulated in the spleen, lung, and brain of HPAI virus-infected chickens. These results suggest that dysfunction of endothelial cells and monocytes/macrophages upon HPAI virus infection may induce hemostasis abnormalities represented by the excessive blood coagulation and consumptive coagulopathy in chickens. 相似文献
35.
Shigematsu T Era S Mizuno Y Ninomiya K Kamegawa Y Morimura S Kida K 《Applied microbiology and biotechnology》2006,72(2):401-415
Abstract
We constructed a mesophilic anaerobic chemostat that was continuously
fed with synthetic wastewater containing propionate as the sole source
of carbon and energy. Steady-state conditions were achieved below the
critical dilution rate of 0.3 d
−1
with almost complete substrate degradation. The propionate-degrading
methanogenic communities in the chemostat at dilution rates of 0.01,
0.08, and 0.3 d
−1
were analyzed using molecular biological techniques. Fluorescence in
situ hybridization with archaeal and bacterial domain-specific probes
showed that archaeal cells predominated throughout the three dilution
rates. Archaeal-16S rRNA gene clone library analysis and quantitative
real-time polymerase chain reaction studies showed that hydrogenotrophic
methanogen rRNA genes closely related to
Methanoculleus
was detected at a dilution rate of 0.01 d
−1
, whereas rRNA genes closely related to the
Methanoculleus
and
Methanospirillum
genera were detected at dilution rates of 0.08 and 0.3 d
−1
. The aceticlastic methanogen,
Methanosaeta
, was detected throughout the three dilution rates. Bacterial-rRNA gene
clone library analysis and denaturing gradient gel electrophoresis
demonstrated that rRNA genes affiliated with the genus
Syntrophobacter
predominated at the low dilution rate, whereas rRNA genes affiliated
with the phylum
Firmicutes
predominated at the higher dilution rates. A significant number of rRNA
genes affiliated with the genus
Pelotomaculum
were detected at dilution rate of 0.3 d
−1
. The diversity of genes encoding acetate kinase agreed closely with the
results of the rRNA gene analysis. The dilution rates significantly
altered the archaeal and bacterial communities in the propionate-fed
chemostat. 相似文献
36.
Summary. Although calcium carbonate is known to be a common biomineral in plants, very little attention has been given to the biological
control of calcium carbonate deposition. In mulberry leaves, a subcellular structure is involved in mineral deposition and
is described here by a variety of cytological techniques. Calcium carbonate was deposited in large, rounded idioblast cells
located in the upper epidermal layer of mulberry leaves. Next to the outmost region (“cap”) of young idioblasts, we found
that the inner cell wall layer expanded to form a peculiar outgrowth, named cell wall sac in this report. This sac grew and
eventually occupied the entire apoplastic space of the idioblast. Inside the mature cell wall sac, various cellulosic membranes
developed and became the major site of Ca carbonate deposition. Concentrated Ca2+ was pooled in the peripheral zone, where small Ca carbonate globules were present in large numbers. Large globules were tightly
packed among multiple membranes in the central zone, especially in compartments formed by cellulosic membranes and in their
neighboring membranes. The maximum Ca sink capacity of a single cell wall sac was quantified using enzymatically isolated
idioblasts as approximately 48 ng. The newly formed outgrowth in idioblasts is not a pure calcareous body but a complex cell
wall structure filled with substantial amounts of Ca carbonate crystals.
Correspondence and reprints: Graduate School of Science and Technology, Kyoto Institute of Technology, Goshokaido, Matsugasaki,
Sakyo, Kyoto 606-8585, Japan. 相似文献
37.
38.
39.
Enzyme-responsive release of encapsulated proteins from biodegradable hollow capsules 总被引:1,自引:0,他引:1
Biodegradable hollow capsules encapsulating proteins were prepared via layer-by-layer assembly of chitosan and dextran sulfate on protein-entrapping mesoporous silica particles and the subsequent removal of the silica. The enzymatic degradation of the capsules in the presence of chitosanase was explored by scanning electron microscopy (SEM). With increasing time, the chitosan component was degraded by chitosanase, and the capsules began to deform and were finally destroyed. Sustained release of the encapsulated proteins was attained by using the enzymatic degradation of the hollow capsules. The release behavior was successfully manipulated by altering the charge of capsule surface. 相似文献
40.
Various proteins are translocated through and inserted into the endoplasmic reticulum membrane via translocon channels. The hydrophobic segments of signal sequences initiate translocation, and those on translocating polypeptides interrupt translocation to be inserted into the membrane. Positive charges suppress translocation to regulate the orientation of the signal sequences. Here, we investigated the effect of membrane cholesterol on the translocational behavior of nascent chains in a cell-free system. We found that the three distinct translocation processes were sensitive to membrane cholesterol. Cholesterol inhibited the initiation of translocation by the signal sequence, and the extent of inhibition depended on the signal sequence. Even when initiation was not inhibited, cholesterol impeded the movement of the positively charged residues of the translocating polypeptide chain. In surprising contrast, cholesterol enhanced the translocation of hydrophobic sequences through the translocon. On the basis of these findings, we propose that membrane cholesterol greatly affects partitioning of hydrophobic segments into the membrane and impedes the movement of positive charges. 相似文献