Relationship of 3 alpha-hydroxysteroid dehydrogenase to pyridine nucleotide transhydrogenases

It appears that the alpha-hydroxysteroid dehydrogenases are not significant entities in promoting transhydrogenase reactions in animal tissues.     

Molecular size of hagfish muscle lactate dehydrogenase

In contrast to an earlier report, we find that the primitive vertebrate Eptatretus possesses a muscle lactate dehydrogenase whose molecular size is like that of lactate dehydrogenases from higher vertebrates. The molecular size of lactate dehydrogenase appears to have remained constant during evolution.     

Peafowl lactate dehydrogenase: problem of isoenzyme identification

Peafowl, like other vertebrates, contain multiple forms of lactate dehydrogenase. The electrophoretic properties of the peafowl isoenzymes are unusual in that the isoenzyme from heart tissue can be either more or less anodic than that of muscle, depending on the pH. This finding focuses attention on the problem of isoenzyme identification. It is suggested that isoenzymes be identified on the basis of properties that are chemically and biologically more significant than electrophoretic mobility.     

四种黄颡鱼乳酸脱氢酶同工酶电泳的研究

黄颡鱼(Pelteabagrus)又名“黄姑子”、黄腊丁、黄鼓鱼等,在湖南,被称为“黄鸭叫”,隶属于鲶形目科,为广布性鱼类,在我国各大水系均有分布,特别是在长江中下游的湖泊更为集中。黄颡鱼喜栖息于水底层,夜间则游至水上层觅食。其肉质细嫩、味道鲜美,已逐渐成为一特种淡水养殖鱼类,其养殖规模有迅速扩大之势。有关黄颡鱼的研究较多,但主要仅集中于生态研究[1-4],发育研究[5,6]和疾病的防治[7-10]等,对黄颡鱼生理生化、亲缘关系等的研究所见报道极少[11]。鱼类同工酶差异是鱼种间不同生化遗传结构的反映,因此我们对分布于洞庭湖区四种黄颡…     

Linkage of lactate dehydrogenase B and C loci in pigeons

Synthesis of lactate dehydrogenase in somatic and gametic tissues of certain avian and mammalian species is controlled by alleles at three loci, A, B, and C. We report breeding experiments with pigeons that conclusively demonstrate linkage between the B and C structural loci in this species. The most probable recombination fraction is zero, and contiguity is not excluded. The upper 95 percent probability limit is 4.5 percent. This tight linkage of two loci that produce closely similar polypeptides suggests that the loci acquired their separate identities through a duplication event. Further-more, the existence of recognizable B- and C-type polypeptides in both the bird and the mammal suggests that the event and the resulting linkage preceded the separation of these fauna. If so, then the linkage has persisted for a very long time.     

Genetic control of lactate dehydrogenase formation in the hagfish Eptatretus stoutii

The isozyme patterns of lactate dehydrogenases of various tissues were studied on 51 hagfish by starch-gel electrophoresis. Nine lactate dehydrogenase phenotypes were encountered, suggesting the coexistence of two alleles at each of the two separate gene loci. There apparently was no interaction between the products of these two separate loci. Even the products of two alleles at the same locus were apparently incapable of forming hybrid molecules, an indication of the possible monomeric nature of each lactate dehydrogenase molecule.     

堆型艾美耳球虫乳酸脱氢酶基因的克隆与表达

克隆了堆型艾美耳球虫(Eimeria acervulina)乳酸脱氢酶(LDH)基因(EaLDH),并在大肠杆菌中成功表达出重组蛋白.根据GenBank中收录的EaLDH核苷酸序列设计特异性引物,以其第一代裂殖体总RNA为模板,采用RT-PCR方法扩增获得EaLDH基因.将EaLDH基因片段与原核表达载体pET28a(+)连接,构建重组表达质粒pET28a(+)-LDH,并在大肠杆菌BL21(DE3)中诱导表达.结果表明,扩增出的EaLDH基因含993 bP的开放阅读框,与GenBank中收录的EaLDH基因序列相似性为98%.诱导后,重组蛋白能够在大肠杆菌中高效表达,融合蛋白相对分子质量约为4.1×104.     

Horseshoe crab lactate dehydrogenase: tissue distribution and molecular weight

Lactate dehydrogenase from Xiphosura (Limulus) polyphemus i D(-)-lactate specific. It does not use L(+)-lactate, alpha-hydroxybutyrate, alpha-hydroxyvalerate, or alpha-hydroxyisocaproate as substrate. In most tissues lactate dehydrogenase is composed of five isozymes with a molecular weight of 140,000 for each, as judged by gel-filtration chromatography. This suggests that the isozyme, are tetramers comprised of varying amounts of two physicochemically distinc subunits.     

Constitution, viability, and lactate dehydrogenase in stationary-phase L-cell suspension cultures

Starved suspension cultures of L cells exhibit a plateau phase of short duration followed by loss of key cellular constituents and rapidly decreasing viability. In contrast, regularly fed,. undiluted cultures remain stationary at a high cell density for prolonged periods without structural alterations or loss of viability. The L cells contain a single lactate dehydrogenase isozyme with an electrophoretic mobility similar to that of lactate-dehydrogenase-5. High-density stationary cultures show a tenfold increase of the specific activity of this enzyme and a recurrent biphasic pattern of carbohydrate utilization with, first, production and, later, consumption of lactate.     

A nitric oxide-inducible lactate dehydrogenase enables Staphylococcus aureus to resist innate immunity

Staphylococcus aureus is one of the most successful human pathogens, colonizing 2 billion individuals worldwide and causing invasive infections even in immunocompetent hosts. S. aureus can evade multiple components of host innate immunity, including the antimicrobial radical nitric oxide (NO.) produced by activated phagocytes. We show that S. aureus is capable of metabolically adapting to nitrosative stress by expressing an NO.-inducible L-lactate dehydrogenase (ldh1, SACOL0222) divergently transcribed from the NO.-detoxifying flavohemoglobin (hmp). L-Lactate production allows S. aureus to maintain redox homeostasis during nitrosative stress and is essential for virulence. NO.-inducible lactate dehydrogenase activity and NO. resistance distinguish S. aureus from the closely related commensal species S. epidermidis and S. saprophyticus.     

Homology of lactate dehydrogenase genes: E gene function in the teleost nervous system

Data obtained from immunochemical studies and the use of allelic variants support the hypothesis that the lactate dehydrogenase isozymes unique to the teleost nervous system are encoded in a third locus. Immunochemical and other studies demonstrate that this third locus is closely related to the lactate dehydrogenase B locus.     

血清乳酸脱氢酶在评估急性溶血性贫血治疗疗效中的价值

目的 了解血清乳酸脱氢酶(LDH)在急性溶血性贫血治疗疗效评估中的价值.方法 选取47例急性溶血性贫血患者,检测所有患者治疗前的血清LDH水平,然后开始糖皮质激素治疗,治疗6周后,对所有患者进行血清LDH检测,并根据疗效将患者分为完全缓解组、部分缓解组及无效组,比较3组患者治疗前后的血清LDH变化.结果 治疗6周后,完全缓解22例,部分缓解18例,无效7例,临床缓解率为85.1％,完全缓解组和部分缓解组患者的血清LDH水平均比治疗前明显下降(P＜0.01),无效组的血清LDH水平则无明显变化.治疗前后血清LDH的下降幅度以完全缓解组为最大,其次为部分缓解组、无效组,组间两两比较差异有统计学意义(P＜0.01).结论 血清LDH水平下降幅度越大,急性溶血性贫血的疗效越好,血清LDH水平检测可作为急性溶血性贫血的治疗疗效评价指标,动态观察有助于判断溶血性疾病进展情况.     

RNA干扰乳酸脱氢酶A对人神经胶质瘤U251细胞生长的影响

目的 体外观察沉默乳酸脱氢酶-A(lactate dehydrogenase-A,LDH-A)对人神经胶质瘤U251细胞增殖和凋亡的影响.方法 免疫印迹试验筛选靶向LDHA的有效shRNA,免疫荧光试验和乳酸含量检测进一步验证沉默效率,台盼兰染色法和克隆形成试验分析沉默LDHA后U251细胞增殖情况,细胞核DAPI染色及caspase 3活性检测分析U251细胞凋亡.结果 沉默序列中sh-LDHA-3转染组LDHA蛋白表达均较sh-NC组下降(P＜0.05);转染96 h后sh-LDHA-3组细胞与对照组相比细胞活力明显下降(P＜0.01),细胞呈现典型凋亡形态且caspase 3活性增强.结论 干扰U251细胞LDH-A表达可抑制细胞增殖并诱导其凋亡.     

假肠膜明串珠菌D-乳酸脱氢酶基因的克隆与表达

利用PCR的方法从假肠膜明串珠菌(Leuconostoc pseudomesenteroides 1159)的DNA中扩增得到D-乳酸脱氢酶基因,构建重组克隆质粒(pMD19-T-DLDH),转化DH5α进行蓝白斑筛选,得到阳性克隆提取质粒双酶切验证。连接pET-32a表达质粒,构建重组表达质粒,提取质粒双酶切、测序验证,测序结果与原序列基本相符。得到重组表达质粒pET-32-DLDH转化BL21大肠杆菌IPTG诱导表达,SDS-PAGE显示有明显大小约为19 ku的特异蛋白条带。     

动物双歧杆菌基因组的研究进展

动物双歧杆菌是一种常用的益生双歧杆菌菌株,常以益生菌的形式添加到乳制品和其他食品中。该研究就动物双歧杆菌基因组的最新研究进展、重要功能基因和比较基因组进行了综述,以期进一步推广应用该菌株。