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941.
942.
Maize (Zea mays L.) seeds differ in their relative tolerance to the anaerobic environment caused by flooding. Seed tolerance to flooding
stress depends on cellular and metabolic processes since gross anatomical responses have not developed at the pre-emergence
stage. The study reported here characterizes the activities of four anaerobic respiratory enzymes: pyruvate decarboxylase
(PDC), alcohol dehydrogenase (ADH), lactate dehydrogenase (LDH), and malic enzyme (ME) in the flood-tolerant A632 and floodsusceptible
Mo 17 inbred maize seeds during flooding at 10 and 25°C. Each inbred consisted of two seed lots possessing 95% and 75% germination
levels. Flooding increased the activities of all four enzymes. However, no consistent correlation between anaerobic enzyme
activity and flood tolerance was observed across genotype, seed quality and flooding temperature. The results indicate that
it may not be feasible to use whole-seed anaerobic enzyme activities to predict maize seed performance under flooding stress.
Contribution from the Soil Drainage Research Unit, USDA-ARS, Columbus, OH, in cooperation with the Ohio Agricultural Research
and Development Center, The Ohio State University. OARDC Journal Article No. 66–86. 相似文献
943.
苹果酸脱氢酶(MDH)是糖代谢中重要的酶。在西方蜜蜂(Apis mellifera L.)中,MDH分为3个区带MDHⅠ、MDHⅡ和MDH Ⅲ。不同级型和不同发育阶段,MDHⅠ和MDH Ⅲ变化不大;MDHⅡ呈现多态现象,由a、b、c3个等位基因编码。东方蜜蜂(A.cerana F.)的MDH由S、F两个等位基因编码,也有报道它是单态性的。MDH在西方蜜蜂研究中应用较多,主要有处女王交配次数;蜂群中的劳动分工;蜜蜂种群遗传组成分析等。MDH和分子生物学的结合研究势必将推动蜜蜂研究的深入和发展。
Research Progress in Malate Dehydrogenase(MDH) of Honeybees
LIU Yan-he1,ZHANG Chuan-xi1,XU Bao-hua2,3,CHEN Sheng-lu1
1.Institute of Applied Entomology,Zhejiang University,Hangzhou 310029,China;
2.College of Animal Science,Zhejiang University,Hangzhou 310029,China;
3.College of Animal Sciences,Shandong Agricaltural University,Taian 271018,China
Abstract:Malate dehydrogenase(MDH) is an important enzyme in glycometabolism.MDH of Apis mellifera showed three enzyme active zones,MDHⅠ,MDHⅡand MDHⅢ.MDHⅠand MDHⅢ maintained relative
stability in different castes and developmental phases,but MDHⅡwas polymorphic,and controlled by three alleles,a,b and c.MDH of Apis cerana was coded by S and F alleles,but some authors reported it is monomorphic.MDH was applied to the studies of A.mellifera,which included several aspects as follows:the number of queen matings,labor division in honeybee societies,the analysis of genetic constitution in honeybee populations and so on.The combination of both MDH and molecular biology will certainly promote honeybee studies.
Key words:honeybees;malate dehydrogenase(MDH) 相似文献
944.
Thomas K. C. Leung Christine Hall Clinton Monfries Louis Lim 《Journal of neurochemistry》1987,49(1):232-238
Neurone-specific enolase (NSE) and the brain form of creatine phosphokinase (CPK-BB) were previously found to be present in rat synaptosomal plasma membranes (SPM) using two-dimensional gel (2-D gel) and peptide analysis; enzymatic activities of these and of pyruvate kinase (PK), all involved in ATP generation, were shown to be "cryptic" unless the SPM were treated with Triton X-100. We now show that enzymatic activation also occurs when the SPM are treated with trifluoperazine (TFP). TFP activation occurred even when the enzymes were membrane associated, showing that solubilization was not responsible for "unmasking" the enzyme activities. When TFP treatment was performed at alkaline instead of neutral pH, NSE and CPK-BB were released as well as PK, nonneuronal enolase, and aldolase which were identified by 2-D gel and tryptic peptide analysis. Other proteins released included calmodulin, actin, and the 70-kilodalton heat-shock cognate protein. Tubulin, synapsin I, and a 35-kilodalton basic protein were largely unaffected. The latter was identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase on the basis of 2-D gel and peptide analyses and subsequent partial sequencing of a rat brain cDNA coding for the same protein. TFP treatment is thus useful for activating latent enzymes as well as for distinguishing enzymes that have a different disposition on the membrane. 相似文献
945.
The murine “housekeeping” enzyme, cytosolic NADP-isocitrate dehydrogenase (E.C. 1.1.1.42) (genetic locus:Idh-1), exhibited a complex pattern of allele-specific expression. Protein electrophoresis on cellulose-acetate gels and determination of relative enzymatic activity by means of densitometry revealed that in heart tissue (but not liver tissue) of certain hybrid crosses the AA-homodimer was underrepresented relative to total enzymatic activity, and the degree of underrepresentation changed during development. In mixtures of homozygous tissue extracts of heart tissue (but not liver tissue) the AA-homodimer was underrepresented relative to the BB-homodimer. Relative activity of allelic isozymes varied as a function of tissue (heart versus liver), age, and the parental source of the Idh-1a allele, but did not vary as a function of sex. Allele-specific expression was also exhibited in kidney tissue of the same animals. In adult male kidney tissue extracts from heterozygotes, the AA-hornodimer was underrepresented relative to total enzymatic activity; in adult female kidney tissue extracts from heterozygotes, a more codominant phenotype was observed. Tissue extracts from immature hybrid animals exhibited a phenotype midway between the adult male and adult female phenotypes. Tissue extracts from castrated males exhibited a phenotype equivalent to that seen in females. Relative activity of allelic isozymes in kidney varied as a function of age and sex, but did not vary as a function of the parental source of the Idh-1a allele. While cytosolic NADP-IDH is a “housekeeping” enzyme, expressed in multiple tissues of the mouse, differences in the relative intensities of allelic isozyme bands provide evidence for tissue- and stage-specific regulatory variation. 相似文献
946.
The activities of a number of enzymes in concentrated solutions of glycinebetaine and other solutes have been studied. Glycinebetaine, in contrast to electrolytes such as NaCl, was found to be noninhibitory up to 500 mM. This is compatible with the postulated role of glycinebetaine in cytoplasmic osmoregulation. Partial protection against NaCl inhibition was afforded by glycinebetaine in some cases. More detailed studies on glycinebetaine —NaCl-enzyme interactions were carried out using malate dehydrogenase (decarboxylating) from Hordeum vulgare.Abbreviations TES
N-tris[hydroxymethyl]methyl-2-aminoethane sulphonic acid
- MES
2[N-Morpholino]ethane sulphonic acid 相似文献
947.
Osvaldo D. Delgado M. Alejandra Martínez Carlos M. Abate Faustino Siñeriz 《Biotechnology letters》2002,24(15):1285-1290
An integrative vector was constructed to allow expression of heterologous proteins into the adhB locus of Zymomonas mobilis. As a reporter gene, the ORF of a bright variant of green fluorescent protein from Aequorea victoria (GFPuv) was fused to the adhB strong promoter from Z. mobilis by using a two-step PCR strategy. Z. mobilis recombinant strains that were stably marked by precise gene replacement at adhB locus with a single chromosomal copy of gfpuv. Protein expression was confirmed by fluorescence microscopy and measured by fluorescence spectroscopy, showing high expression levels (12 to 30 times higher than those obtained in E. coli) without affecting the host growth. 相似文献
948.
Yan Du Mei‐ju Zhang Lan‐lan Li Xiao‐Lin Xu Hao Chen Yu‐bin Feng Yan Li Xiao‐qin Peng Fei‐hu Chen 《Journal of cellular and molecular medicine》2020,24(12):6952-6965
Acute myeloid leukaemia (AML) remains a therapeutic challenge and improvements in chemotherapy are needed. 4‐Amino‐2‐trifluoromethyl‐phenyl retinate (ATPR), a novel all‐trans retinoic acid (ATRA) derivative designed and synthesized by our team, has been proven to show superior anticancer effect compared with ATRA on various cancers. However, its potential effect on AML remains largely unknown. Lactate dehydrogenase B (LDHB) is the key glycolytic enzyme that catalyses the interconversion between pyruvate and lactate. Currently, little is known about the role of LDHB in AML. In this study, we found that ATPR showed antileukaemic effects with RARα dependent in AML cells. LDHB was aberrantly overexpressed in human AML peripheral blood mononuclear cell (PBMC) and AML cell lines. A lentiviral vector expressing LDHB‐targeting shRNA was constructed to generate a stable AML cells with low expression of LDHB. The effect of LDHB knockdown on differentiation and cycle arrest of AML cells was assessed in vitro and vivo, including involvement of Raf/MEK/ERK signalling. Finally, these data suggested that ATPR showed antileukaemic effects by RARα/LDHB/ ERK‐glycolysis signalling axis. Further studies should focus on the underlying leukaemia‐promoting mechanisms and investigate LDHB as a therapeutic target. 相似文献
949.
O. Erice I. Labiano A. Arbelaiz A. Santos-Laso P. Munoz-Garrido R. Jimenez-Agüero P. Olaizola A. Caro-Maldonado N. Martín-Martín A. Carracedo E. Lozano J.J. Marin C.J. ORourke J.B. Andersen J. Llop V. Gómez-Vallejo D. Padro A. Martin J.M. Banales 《生物化学与生物物理学报:疾病的分子基础》2018,1864(4):1335-1344
Background and aims
Cholangiocarcinoma (CCA) is an aggressive tumor type affecting cholangiocytes. CCAs frequently arise under certain cholestatic liver conditions. Intrahepatic accumulation of bile acids may facilitate cocarcinogenic effects by triggering an inflammatory response and cholangiocyte proliferation. Here, the role of bile acid receptors FXR and TGR5 in CCA progression was evaluated.Methods
FXR and TGR5 expression was determined in human CCA tissues and cell lines. An orthotopic model of CCA was established in immunodeficient mice and tumor volume was monitored by magnetic resonance imaging under chronic administration of the specific FXR or TGR5 agonists, obeticholic acid (OCA) or INT-777 (0,03% in chow; Intercept Pharmaceuticals), respectively. Functional effects of FXR or TGR5 activation were evaluated on CCA cells in vitro.Results
FXR was downregulated whereas TGR5 was upregulated in human CCA tissues compared to surrounding normal liver tissue. FXR expression correlated with tumor differentiation and TGR5 correlated with perineural invasion. TGR5 expression was higher in perihilar than in intrahepatic CCAs. In vitro, FXR was downregulated and TGR5 was upregulated in human CCA cells compared to normal human cholangiocytes. OCA halted CCA growth in vivo, whereas INT-777 showed no effect. In vitro, OCA inhibited CCA cell proliferation and migration which was associated with decreased mitochondrial energy metabolism. INT-777, by contrast, stimulated CCA cell proliferation and migration, linked to increased mitochondrial energy metabolism.Conclusion
Activation of FXR inhibits, whereas TGR5 activation may promote, CCA progression by regulating proliferation, migration and mitochondrial energy metabolism. Modulation of FXR or TGR5 activities may represent potential therapeutic strategies for CCA. 相似文献950.
W.F. Theeuwes H.R. Gosker R.C.J. Langen N.A.M. Pansters A.M.W.J. Schols A.H.V. Remels 《生物化学与生物物理学报:疾病的分子基础》2018,1864(9):2913-2926