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Cabbage leaf discs (Brassica oleracea L., Capitata group) were floated adaxial side up in 0, 0.05, or 0.25 m CaCl2 solutions at 15°C for 14 d in the dark. To assess whether the delay of senescence by calcium treatment involved protection of membrane lipids, chlorophyll and protein content and the lipid composition of the membranes were determined during incubation. Chlorophyll and protein content decreased with time, in correlation with a reduction in the amount of phospholipids. The degree of unsaturation of phospholipids and free fatty acids decreased, whereas the ratio of sterol to phospholipid increased. The proportions of phospholipid classes did not change during senescence. The catabolism of phospholipids was delayed by 0.05 m calcium, but accelerated by 0.25 m, as compared to the untreated control. Based on the levels of the lipid intermediates, phospholipase D, phosphatidic acid phosphatase, lipolytic acyl hydrolase, and lipoxygenase appeared to be involved in the breakdown of phospholipids during senescence. Phospholipase D and phosphatidic acid phosphatase may be directly influenced by calcium. The calcium treatment apparently did not affect the activity of acyl hydrolase. Lipoxygenase, responsible for the peroxidation of the polyunsaturated fatty acids, was probably indirectly influenced by calcium. We conclude that the delay of senescence of cabbage leaf discs by calcium treatment involved protection of membrane lipids from degradation. 相似文献
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Kumari Anjali Ameri Shijin Ravikrishna Palavancha Dhayalan Arul Kamala-Kannan S. Selvankumar T. Govarthanan M. 《International journal of peptide research and therapeutics》2020,26(2):1051-1059
International Journal of Peptide Research and Therapeutics - Marine snails are abundant sources of biologically important conopeptides with their potential applications in drug development. The... 相似文献
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The mitochondrial respiratory uncoupling protein 1 (UCP1) partially uncouples substrate oxidation and oxidative phosphorylation to promote the dissipation of cellular biochemical energy as heat in brown adipose tissue. We have recently shown that expression of UCP1 in 3T3-L1 white adipocytes reduces the accumulation of triglycerides. Here, we investigated the molecular basis underlying UCP1 expression in 3T3-L1 adipocytes. Gene expression data showed that forced UCP1 expression down-regulated several energy metabolism pathways; but ATP levels were constant. A metabolic flux analysis model was used to reflect the gene expression changes onto metabolic processes and concordance was observed in the down-regulation of energy consuming pathways. Our data suggest that adipocytes respond to long-term mitochondrial uncoupling by minimizing ATP utilization. 相似文献
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The role of calpain in the proteolytic cleavage of E-cadherin in prostate and mammary epithelial cells 总被引:7,自引:0,他引:7
Rios-Doria J Day KC Kuefer R Rashid MG Chinnaiyan AM Rubin MA Day ML 《The Journal of biological chemistry》2003,278(2):1372-1379
The E-cadherin protein mediates Ca(2+)-dependent interepithelial adhesion. Association of E-cadherin with the catenin family of proteins is critical for the maintenance of a functional adhesive complex. We have identified a novel truncated E-cadherin species of 100-kDa (E-cad(100)) in prostate and mammary epithelial cells. E-cad(100) was generated by treatment of cells with ionomycin or TPA. Cell-permeable calpain inhibitors prevented E-cad(100) induction by ionomycin. Immunoblotting for spectrin and mu-calpain confirmed calpain activation in response to ionomycin treatment. Both the mu- and m-isoforms of calpain efficiently generated E-cad(100) in vitro. The E-cad(100) fragment was unable to bind to beta-catenin, gamma-catenin, and p120, suggesting that this cleavage event would disrupt the E-cadherin adhesion complex. Mutational analysis localized the calpain cleavage site to the cytosolic domain upstream of the beta- and gamma-catenin binding motifs of E-cadherin. Because E-cadherin is inactivated in many adenocarcinomas we hypothesized that calpain may play a role in prostate tumorigenesis. A prostate cDNA microarray data base was analyzed for calpain expression in which it was found that m-calpain was up-regulated in localized prostate cancer, and to an even higher degree in metastatic prostate cancer compared with normal prostate tissue. Furthermore, we examined the cleavage of E-cadherin in prostate cancer specimens and found that E-cad(100) accumulated in both localized and metastatic prostate tumors, supporting the cDNA microarray data. These findings demonstrate a novel mechanism by which E-cadherin is functionally inactivated through calpain-mediated proteolysis and suggests that E-cadherin is targeted by calpain during the tumorigenic progression of prostate cancer. 相似文献
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We report on generation of marker-free (‘clean DNA’) transgenic rice (Oryza sativa), carrying minimal gene-expression-cassettes of the genes of interest, and evaluation of its resistance to yellow stem borerScirpophaga incertulas (Lepidoptera: Pyralidae). The transgenicindica rice harbours a translational fusion of 2 differentBacillus thuringiensis (Bt) genes, namelycry1B-1Aa, driven by the green-tissue-specific phosphoenol pyruvate carboxylase (PEPC) promoter. Mature seed-derived calli of an eliteindica rice cultivar Pusa Basmati-1 were co-bombarded with gene-expression-cassettes (clean DNA fragments) of the Bt gene and the
markerhpt gene, to generate marker-free transgenic rice plants. The clean DNA fragments for bombardment were obtained by restriction
digestion and gel extraction. Through biolistic transformation, 67 independent transformants were generated. Transformation
frequency reached 3.3%, and 81% of the transgenic plants were co-transformants. Stable integration of the Bt gene was confirmed,
and the insert copy number was determined by Southern analysis. Western analysis and ELISA revealed a high level of Bt protein
expression in transgenic plants. Progeny analysis confirmed stable inheritance of the Bt gene according to the Mendelian (3∶1)
ratio. Insect bioassays revealed complete protection of transgenic plants from yellow stem borer infestation. PCR analysis
of T2 progeny plants resulted in the recovery of up to 4% marker-free transgenic rice plants. 相似文献
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Davis GD Masilamoni JG Arul V Kumar MS Baraneedharan U Paul SF Sakthivelu IV Jesudason EP Jayakumar R 《Cell biology and toxicology》2009,25(4):331-340
During the course of cancer radiation treatment, normal skin invariably suffers from the cytotoxic effects of γ-radiation
and reactive oxygen species (ROS), which are generated from the interaction between radiation and the water molecules in cells.
The present study was designed to investigate the radioprotective role of α-lipoic acid (LA), an antioxidant on murine skin
fibroblasts exposed to a single dose of 2, 4, 6, or 8Gy γ-radiation. Irradiation of fibroblasts significantly increased ROS,
nitric oxide, and lipid peroxidation (P < 0.001); all of these factors substantially decreased with 100 μM LA treatment. Hydroxyl radical (OH⋅) production from 8Gy irradiated fibroblasts was measured directly by electron spin resonance using spin-trapping techniques.
LA was found to inhibit OH⋅ production at 100-μM concentrations. Dose-dependent depletion of antioxidants, such as catalase and glutathione reductase,
was observed in irradiated fibroblasts (P < 0.001), along with increased superoxide dismutase (P < 0.001). LA treatment restored antioxidant levels. Concentration of the pro-inflammatory cytokine IL-1β was significantly
reduced in irradiated fibroblasts when treated with LA. MTT and lactate dehydrogenase assays demonstrated that LA treatment
reduced cell injury and protected cells against irradiation-induced cytotoxicity. Thus, we conclude that results are encouraging
and need further experiments to demonstrate a possible benefit in cancer patients and the reduction of harmful effects of
radiation therapy. 相似文献
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Detailed structural analysis of protein necessitates investigation at primary, secondary and tertiary levels, respectively. Insight into protein secondary structures pave way for understanding the type of secondary structural elements involved (α-helices, β-strands etc.), the amino acid sequence that encode the secondary structural elements, number of residues, length and, percentage composition of the respective elements in the protein. Here we present a standalone tool entitled "ExSer" which facilitate an automated extraction of the amino acid sequence that encode for the secondary structural regions of a protein from the protein data bank (PDB) file. AVAILABILITY: ExSer is freely downloadable from http://code.google.com/p/tool-exser/ 相似文献
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Chan Chung Matthew J. Elrick James M. Dell’Orco Zhaohui S. Qin Shanker Kalyana-Sundaram Arul M. Chinnaiyan Vikram G. Shakkottai Andrew P. Lieberman 《PLoS genetics》2016,12(5)
Selective neuronal vulnerability is characteristic of most degenerative disorders of the CNS, yet mechanisms underlying this phenomenon remain poorly characterized. Many forms of cerebellar degeneration exhibit an anterior-to-posterior gradient of Purkinje cell loss including Niemann-Pick type C1 (NPC) disease, a lysosomal storage disorder characterized by progressive neurological deficits that often begin in childhood. Here, we sought to identify candidate genes underlying vulnerability of Purkinje cells in anterior cerebellar lobules using data freely available in the Allen Brain Atlas. This approach led to the identification of 16 candidate neuroprotective or susceptibility genes. We demonstrate that one candidate gene, heat shock protein beta-1 (HSPB1), promoted neuronal survival in cellular models of NPC disease through a mechanism that involved inhibition of apoptosis. Additionally, we show that over-expression of wild type HSPB1 or a phosphomimetic mutant in NPC mice slowed the progression of motor impairment and diminished cerebellar Purkinje cell loss. We confirmed the modulatory effect of Hspb1 on Purkinje cell degeneration in vivo, as knockdown by Hspb1 shRNA significantly enhanced neuron loss. These results suggest that strategies to promote HSPB1 activity may slow the rate of cerebellar degeneration in NPC disease and highlight the use of bioinformatics tools to uncover pathways leading to neuronal protection in neurodegenerative disorders. 相似文献
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