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31.
Sowmyalakshmi Srinivasan Raj Kumar Srinivas Koduru Aaditya Chandramouli Chendil Damodaran 《Apoptosis : an international journal on programmed cell death》2010,15(2):153-161
The tumor necrosis factor (TNF) receptor super family comprises of members that induce two distinct signaling cascades, leading
to either cell survival or apoptosis. However, in prostate cancer (PCa), TNF-mediated prosurvival signaling is the predominant
pathway that leads to cell survival and resistance to therapy. Although inhibition of TNF signaling by pharmacological agents
or monoclonal antibodies has gained importance in the field of cancer therapy, toxicity to normal cells has impaired their
extensive use for cancer treatment. We previously identified a natural, nontoxic compound psoralidin that inhibited viability
and induced apoptosis in androgen independent prostate cancer (AIPC) cells. Thus, the goal of our study is to investigate
whether psoralidin inhibits TNF-mediated prosurvival signaling in AIPC cells. Our results suggest that psoralidin inhibits
constitutive and TNF-induced expression of TNF-α and its downstream prosurvival signaling molecules such as NF-κB and Bcl-2
in AIPC cells. On the other hand, psoralidin simultaneously induces the death receptor (DR)-mediated apoptotic signaling eventually
causing the activation of caspase cascade and resultant induction of apoptosis. Oral administration of psoralidin inhibits
expression of TNF-α and NF-κB/p65 in tumor sections, resulting in tumor regression in PC-3 xenografts. Our results suggest
that psoralidin inhibits TNF-mediated survival signaling in AIPC and thus is a potent therapeutic agent for prostate cancer. 相似文献
32.
33.
C. K. M. Rathnam 《Planta》1979,145(1):13-23
The potential for glycolate and glycine metabolism and the mechanism of refixation of photorespiratory CO2 in leaves of C4 plants were studied by parallel inhibitor experiments with thin leaf slices, different leaf cell types and isolated mitochondria of C3 and C4
Panicum species. CO2 evolution by leaf slices of P. bisulcatum, a C3 species, fed glycolate or glycine was light-independent and O2-sensitive. The C4
P. maximum and P. miliaceum leaf slices fed glycolate or glycine evolved CO2 in the dark but not in the light. In C4 species, dark CO2 evolution was abolished by the addition of phosphoenolpyruvate (PEP)4. The addition of maleate, a PEP carboxylase inhibitor, resulted in photorespiratory CO2 efflux by C4 leaf slices in the light also. However, PEP and maleate had no effect on either glycolate-dependent O2 uptake by the C4 leaf slices or on glycolate and glycine metabolism in C3 leaf slices. The rate of photorespiratory CO2 evolution in the C3
Panicum species was 3 times higher than that observed with the C4 species. The ratio of glycolate-dependent CO2 evolution to O2 uptake in both groups was 1:2. Isolated C4 mesophyll protoplasts or their mitochondria did not metabolize glycolate or glycine. However, both C3 mesophyll protoplasts and C4 bundle sheath strands readily metabolized glycolate and glycine in a light-independent, O2-sensitive manner, and the addition of PEP or maleate had no effect. C4 bundle sheath- and C3-mitochondria were capable of oxidizing glycine. This oxidation was linked to the mitochondrial electron transport chain, was coupled to three phosphorylation sites and was sensitive to electron transport inhibitors. C4 bundle sheath- and C3-mitochondrial glycine decarboxylation was stimulated by oxaloacetate and NAD had no effect. In marked contrast, mitochondria isolated from C4 mesophyll cells were incapable of oxidizing or decarboxylating added glycine. The results suggest that in leaves of C4 plants bundle sheath cells are the primary site of O2-sensitive photorespiratory CO2 evolution and the PEP carboxylase present in the mesophyll cells has the Potential for efficiently refixing CO2 before it escapes out of the leaf. The relative role of the PEP carboxylase mediated CO2 pump and reassimilation of photorespiratory CO2 are discussed in relation to the apparent lack of photorespiration in leaves of C4 species.Abbreviations BSA
bovine serum albumin
- Chl
chlorophyll
- PEP
phosphoenolpyruvate
- Rbu-P
2
ribulose 1,5-bisphosphate
- Rib-5-P
ribose-5-phosphate
- Ru-5-P
ribuluse-5-phosphate
- FCCP
carbonyl cyanide p-trifluoromethoxyphenylhydrazone
Journal Series Paper, New Jersey Agricultural Experiment Station 相似文献
34.
Both malate and aspartate were decarboxylated at the 4-carbonposition by isolated bundle sheath strands of C4 plants butto different extents depending upon the species. In Digitariasanguinalis, an NADP-malic enzyme (NADP-ME) species, 100 µMoxalic acid blocked malate decarboxylation through NADP-ME withoutaffecting aspartate decarboxylation which apparently occursthrough NAD-ME. In several phosphoenolpyruvate carboxykinase(PEP-CK) type C4 species, 200 µM 3-mercaptopicolinic acid(3-MPA), an inhibitor of PEP-CK, specifically inhibited themalate decarboxylation and partially inhibited aspartate decarboxylation.The aspartate decarboxylation insensitive to 3-MPA may occurthrough NAD-ME. Neither inhibitor prevented C4 acid decarboxylationin bundle sheath cells of NAD-ME species. The inhibitors thusserved to differentiate between the decarboxylation of C4 acidsin PEP-CK and NADP-ME type C4 species through their major decarboxylasefrom that of their less active decarboxylation through NAD-ME.
1 Present address: Department of Biochemistry and Microbiology,Rutgers University, New Brunswick, NJ 08903, U. S. A. (Received January 28, 1977; ) 相似文献
35.
C4-acid metabolism by isolated bundlesheath chloroplasts, mitochondria and strands of Eriochloa borumensis Hack., a phosphoennolpyruvate-carboxykinase (PEP-CK) species, was investigated. Aspartate, oxaloacetate (OAA) and malate were decarboxylated by strands with several-fold stimulation upon illumination. There was strictly light-dependent decarboxylation of OAA and malate by the chloroplasts, but the chloroplasts did not decarboxylate aspartate in light or dark. PEP was a primary product of OAA or malate decarboxylation by the chloroplasts and its formation was inhibited by 3-(3,4-dichlorophenyl)-1, 1-dimethylurea or NH4Cl. There was very little conversion of PEP to pyruvate by bundle-sheath chloroplasts, mitochondria or strands. Decarboxylation of the three C4-acids by mitochondria was light-independent. Pyruvate was the only product of mitochondrial metabolism of C4-acids, and was apparently transaminated in the cytoplasm since PEP and alanine were primarily exported out of the bundle-sheath strands. Light-dependent C4-acid decarboxylation by the chloroplasts is suggested to be through the PEP-CK, while the mitochondrial C4-acid decarboxylation may proceed through the NAD-malic enzyme (NAD-ME) system. In vivo both aspartate and malate are considered as transport metobolites from mesophyll to bundle-sheath cells in PEP-CK species. Aspartate would be metabolized by the mitochondria to OAA. Part of the OAA may be converted to malate and decarboxylated through NAD-ME, and part may be transported to the chloroplasts for decarboxylation through PEP-CK localized in the chloroplasts. Malate transported from mesophyll cells may serve as carboxyl donor to chloroplasts through the chloroplastic NAD-malate dehydrogenase and PEP-CK. Bundle-sheath strands and chloroplasts fixed 14CO2 at high rates and exhibited C4-acid-dependent O2 evolution in the light. Studies with 3-mercaptopicolinic acid, a specific inhibitor of PEP-CK, have indicated that most (about 70%) of the OAA formed from aspartate is decarboxylated through the chloroplastic PEP-CK and the remaining (about 30%) OAA through the mitochondrial NAD-ME. Pyruvate stimulation of aspartate decarboxylation is discussed; a pyruvate-alanine shuttle and an aspartate-alanine shuttle are proposed between the mesophyll and bundle-sheath cells during aspartate decarboxylation through the PEP-CK and NAD-ME system respectively.Abbreviations CK
carboxykinase
- -Kg
-ketoglutarate
- ME
malic enzyme
- 3-MPA
3-mercaptopicolinic acid
- OAA
oxaloacetate
- PEP
phosphoenolpyruvate
- R5P
ribose-5-phosphate 相似文献
36.
Amino acid sequence of the beta subunit of follicle-stimulating hormone from human pituitary glands.
The beta subunit of follicle-stimulating hormone (FSH-beta) from human pituitary glands was reduced and S-aminoethylated prior to thermolytic, tryptic, and chymotryptic digestions. Each digest was gel-filtered on Sephadex G-50 to seperate the glycopeptides. The glycopeptides and the peptides were isolated by high voltage paper electrophoresis at pH 6, 3.5, and 2.0. The purity of the isolated peptides was confirmed by amino acid analyses. The amino acid sequences of peptides were determined by Edman degradation followed by subtractive amino acid analysis and, in certain cases, confirmed by dansylation. COOH-terminal sequences of the peptides were determined by digestion with carboxypeptidases A and B and by hydrazinolysis. The tryptophan content of human follicle-stimulating hormone, of the beta subunit of human follicle-stimulating hormone, and of the glycopeptides obtained from the enzymic digests was determined by fluorescence spectra, titration against N-bromosuccinimide, colorimetric estimation with p-dimethyl aminobenzaldehyde, hydrolysis with methane sulfonic acid containing 0.2% tryptamine followed by amino acid analysis, microbiological assay, and sequence analysis. The presence of 1 tryptophan residue in the beta subunit was indicated. 相似文献
37.
Previs SF Fatica R Chandramouli V Alexander JC Brunengraber H Landau BR 《American journal of physiology. Endocrinology and metabolism》2004,286(4):E665-E672
A method is introduced for quantitating protein synthetic rates in humans by use of (2)H(2)O. Its validity was tested in subjects with end-stage renal disease. Six clinically stable subjects, hemodialyzed three times weekly, ingested (2)H(2)O to a body water (2)H enrichment of approximately 0.4%. On dialysis, body water enrichment declined to approximately 0.1%. Enrichment of the alpha-hydrogen of plasma free alanine was also approximately 0.4% before and approximately 0.1% after dialysis. Beta-hydrogen enrichment was approximately 80-100% of alpha-hydrogen enrichment. (2)H(2)O was ingested to replace (2)H(2)O removed after each dialysis for 15-51 days, returning enrichment to approximately 0.4%. Enrichment of alanine from plasma albumin gradually increased, with again approximately 80-100% as much (2)H in beta- as in alpha-hydrogens. With continued dialyses, without (2)H(2)O replacement, alanine from albumin enrichment gradually declined, whereas free alanine and water enrichments were negligible. The fractional albumin synthesis rate, calculated from the increase in enrichment in alanine from albumin, was 4.0 +/- 0.5%/day, and from the decrease, 4.6 +/- 0.2%/day. Thus body water enrichment in a subject given (2)H(2)O can be maintained constant long term. A rapid exchange, essentially complete, occurs between the hydrogens of alanine and body water. An integrated measure over a long period of albumin's synthetic rate can be estimated from both the rise in enrichment of alanine from the protein during (2)H(2)O ingestion and fall on (2)H(2)O withdrawal, while the subject's living routine is uninterrupted. Estimates are in subjects with renal disease, but the method should be applicable to estimates of protein synthetic rates in normal subjects and in other pathological states. 相似文献
38.
Antibiotic Resistance Genes Online (ARGO): a Database on vancomycin and beta-lactam resistance genes 总被引:1,自引:0,他引:1
Vancomycin and beta-lactams are antibiotics that inhibit gram positive bacteria by interfering with cell wall synthesis. However, continuous use of antibiotics results in the emergence of multi-drug resistant (MDR) bacterial strains. Here, we describe ARGO, a database containing gene sequences conferring resistance to these two classes of antibiotics. It is designed as a resource to enhance research on the prevalence and spread of antibiotic resistance genes. ARGO is the first attempt to compile the resistance gene sequence data with state specific information. AVAILABILITY: AGRO is available for free at http://www.argodb.org/ 相似文献
39.
Tsai MH Yan H Chen X Chandramouli GV Zhao S Coffin D Coleman CN Mitchell JB Chuang EY 《Molecular biotechnology》2005,29(3):221-224
We compared different hybridization conditions of oligonucleotide-based DNA microarray to acquire optimized and reliable microarray
data. Several parameters were evaluated at different hybridization conditions, including signal-to-background (S:B) ratios,
signal dynamic range, usable spots, and reproducibility. Statistical analysis showed that better results were obtained when
spotted, presynthesized long oligonucleotide arrays were blocked with succinic anhydride and hybridized at 42°C in the presence
of 50% formamide. 相似文献
40.
David Petersen GVR Chandramouli Joel Geoghegan Joanne Hilburn Jonathon Paarlberg Chang Hee Kim David Munroe Lisa Gangi Jing Han Raj Puri Lou Staudt John Weinstein J Carl Barrett Jeffrey Green Ernest S Kawasaki 《BMC genomics》2005,6(1):1-14