Effect of Fish Oil Diet on Fatty Acid Composition of Phospholipids of Brain Membranes and on Kinetic Properties of Na+, K+-ATPase Isoenzymes of Weaned and Adult Rats

Abstract: The influence of dietary (n-3) fatty acids (such as eicosapentaenoic and docosahexaenoic acids) as found in fish oil on Na⁺ sensitivity and ouabain affinity of Na⁺, K⁺-ATPase isoenzymes (α1, α2, α3) was studied in whole brain membranes from weaned and adult rats fed diets for two generations. The long chain (n-3) fatty acids supplied by fish oil decreased the fatty acids of the (n-6) series compared with the standard diet, resulting in a decrease in the (n-6)/(n-3) molar ratio in both 21 - and 60-day- old rats. On the basis of ouabain titration, three inhibitory processes with markedly different affinities were associated with isoenzymes, i.e., low affinity (α1), high affinity (α2), and very high affinity (α3). It appears that the fish oil diet, in part via the modification of membrane fatty acid composition, altered the proportion and ouabain affinity of isoenzymes. Na⁺ sensitivity is the best criterion of physiologic change induced by fish oil diet. We calculated the Na⁺ activation for each isoenzyme and found one Na⁺ sensitivity and two Na⁺ sensitivities per isoenzyme in weanling and adult rats fed different diets, respectively. In contrast to α2 and α3, α1 appears insensitive to membrane change induced by fish oil diet. Fish oil diet, which is known to confer cardioprotection, induced significant modulation of Na⁺, K⁺-ATPase isoenzymes at the brain level.     

Chloroplast and Cytosol Isozymes of Cu,Zn-Superoxide Dismutase: Their Characteristic Amino Acid Sequences

lsozymes of CuZn-superoxide dismutase (SOD) were purified from angiosperms (spinach and rice), fern (horsetail) and green alga (Spirogyra). Occurrence of CuZn-SOD was confirmed by its purification in the group of green algae which shows the phragmoplast type of cell division. Purified CuZn-SODS are divided to chloroplast and cytosol types by their cellular localization and immunological properties. Their amino acid compositions, absorption spectra, CD spectra, and sensitivity to hydrogen peroxide also are distinguished from each other. All organisms including Spirogyra contain both types of isozyme. Thus, the divergence of the two types of CuZn-SOD isozyme occurred immediately after its acquisition by the most evolved green algae.

Amino acid sequences of amino-terminal regions of CuZn-SOD isozyrnes from spinach, rice and horsetail were determined and compared with those of CuZn-SODS from other plants. The chloroplast and cytosol isozymes of CuZn-SOD show each characteristic sequences. Sequence differences among the cytosol CuZn-SODS are greater than those among the chloroplast CuZn-SODS. These observations indicate that each type of isozyme had independently evolved after the acquisition of CuZn-SOD.     

Analysis of the genetic similarities among seven species of Prosopis (Leguminosae:Mimosoideae)

Summary Prosopis (mesquite) is a commercially promising plant genus that has received increased attention lately. Allelic frequencies at 25 enzyme loci in seven species from the section Algarobia were transformed in matrices of genetic distance using three methods. The indices give highly correlated results; only in the cluster Prosopis alba -P. hassleri were minor discrepancies evident. The phenetic relationships observed agree with other biochemical evidence (chromatography of phenol compounds, electrophoresis of seed proteins, etc) but not with morphological groupings. The present data support the hypothesis that the species belonging to the section Algarobia would be equivalent to sub- or semispecies; the community of such sympatric subspecies constitutes a syngameon.     

Molecular analysis of glyceraldehyde-3-phosphate dehydrogenase in Trypanoplasma borelli: An evolutionary scenario of subcellular compartmentation in Kinetoplastida

In Trypanoplasma borelli, a representative of the Bodonina within the Kinetoplastida, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity was detected in both the cytosol and glycosomes. This situation is similar to that previously found in Trypanosomatidae, belonging to a different Kinetoplastida suborder. In Trypanosomatidae different isoenzymes, only distantly related, are responsible for the activity in the two cell compartments. In contrast, immunoblot analysis indicated that the GAPDH activity in cytosol and glycosomes of T. borelli should be attributed to identical or at least very similar proteins related to the glycosomal GAPDH of Trypanosomatidae. Moreover, only genes related to the glycosomal GAPDH genes of Trypanosomatidae could be detected. All attempts to identify a gene related to the one coding for the trypanosomatid cytosolic GAPDH remained unsuccessful. Two tandemly arranged genes were found which are 95% identical. The two encoded polypeptides differ in 17 residues. Their sequences are 72–77% identical to the glycosomal GAPDH of the other Kinetoplastida and share with them some characteristic features: an excess of positively charged residues, specific insertions, and a small carboxy-terminal extension containing the sequence -AKL. This tripeptide conforms to the consensus signal for targeting of proteins to glycosomes. One of the two gene copies has undergone some mutations at positions coding for highly conserved residues of the active site and the NAD⁺-binding domain of GAPDH. Modeling of the protein's three-dimensional structure suggested that several of the substitutions compensate each other, retaining the functional coenzyme-binding capacity, although this binding may be less tight. The presented analysis of GAPDH in T. borelli gives further support to the assertion that one isoenzyme, the cytosolic one, was acquired by horizontal gene transfer during the evolution of the Kinetoplastida, in the lineage leading to the suborder Trypanosomatina (Trypanosome, Leishmania), after the divergence from the Bodonina (Trypanoplasma). Furthermore, the data clearly suggest that the original GAPDH of the Kinetoplastida has been compartmentalized during evolution.Abbreviations GAPDH glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) - HK hexokinase (EC 2.7.1.1) - PGI glucosephosphate isomerase (EC 5.3.1.9) - PGK phosphoglycerate kinase (EC 2.7.2.3) - PYK pyruvate kinase (EC 2.7.1.40) - TIM triosephosphate isomerase (EC 5.3.1.1) - SDS sodium dodecyl sulfate - SSC saline sodium citrate (0.15 M NaCl, 15 mM sodium citrate, pH 7.0) - MYR millions of years Nucleotide sequence data reported in this paper have been submitted to the EMBL/Genbank/DDBJ nucleotide sequence databases under accession number X74535 Correspondence to: P.A.M. Michels     

鳙团移核鱼LDH,MDH同工酶的研究

对二龄鳙鱼细胞核和团头鲂细胞质配合的核质杂种鱼－－鳙团移核鱼及其亲本,供核体鳙鱼和受核体团头鲂肌组织ＬＤＨ、ＭＤＨ同工酶进行了研究试验。鳙团移核鱼和供核体鳙鱼肌组织ＬＤＨ同工酶均具有ＬｄｈＡ２Ｂ２一条谱带;受核体团头鲂的则具有ＬｄｈＡ２、ＬｄｈＡ２Ｂ１、ＬｄｈＡ２Ｂ２、ＬｄｈＡ１Ｂ３、ＬｄｈＢ４等五条谱带。移核鱼和供核体鳙鱼肌组织的ＭＤＨ同工酶都各具有二条谱带：Ｓ－ｍｄｈＡ２、Ｓ－ｍｄｈＡＢ;受核     

Changes in arginase isoenzymes pattern in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide affecting preferentially patients with liver cirrhosis. The studies were performed on tissues obtained during surgery from 50 patients with HCC, 40 with liver cirrhosis and 40 control livers. It was found that arginase activity in HCC was nearly 5- and 15-fold lower than in cirrhotic and normal livers, respectively. Isoenzymes AI (so-called liver-type arginase) and AII (extrahepatic arginase) were identified by Western blotting in all studied tissues, however the amount of AI, as well as the expression of AI-mRNA were lower in HCC, in comparison with normal liver, and those of AII were significantly higher. Since HCC is arginine-dependent, and arginine is essential for cells growth, the decrease of AI may preserve this amino acid within tumor cells. Concurrently, the rise of AII can increase the level of polyamines, compounds crucial for cells proliferation. Thus, both arginase isoenzymes seem to participate in liver cancerogenesis.     

Glutamine synthetase isoenzymes of Phaseolus vulgaris L.: subunit composition in developing root nodules and plumules

In the legume Phaseolus vulgaris L., glutamine synthetase (GS) (EC.6.3.1.2.) occurs as three cytosolic polypeptides, , and , and a plastidic polypeptide, . This paper describes the subunit composition of active octameric GS isoenzymes from root nodules and plumules using ionexchange high-performance liquid chromatography followed by two-dimensional denaturing gel electrophoresis and Western immunodetection. Root nodules contained four separable GS activities, three of which were composed mainly of cytosolic , / and GS polypeptides, whereas the fourth activity, consisted of plastidic GS polypeptides. The increase in GS activity during nodulation was due largely to the appearance of -containing isoenzymes, and to a lesser extent on the isoenzyme, whereas the -isoenzyme activity remained approximately constant throughout. Plumule GS from imbibed seeds was found to be composed of separate and isoenzymes, but 2 d after germination, plumule GS consisted of a mixture of , / and isoenzymes. The results from both nodules and plumules indicate that different cytosolic GS polypeptides in P. vulgaris are able to assemble into both homo-octameric and heterooctameric isoenzymes. Moreover, the changes in the patterns of isoenzymes observed during nodule development and plumule growth are interpreted to be caused both by temporal changes in the denovo synthesis of the polypeptides and also by their spatial separation in different cell types.Abbreviations 1D, 2D one-, two-dimensional - GS glutamine synthetase - GS_s GS semibiosynthetic activity - GS_t GS transferase activity - IEX-HPLC ion-exchange high-performance liquid chromatography - kDa kilodaltons - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis     

同功酶电泳图谱在放线菌分类中的应用研究

从国内外收集部分放线菌的典型菌种,研究它们6种同功酶的凝胶电泳图谱。并进行了聚类分析。与现有分类方法比较,讨论了同功酶图谱应用于放线菌分类的可能性及相关的问题。认为同功酶电泳图谱可以作为分类方法之一在放线菌分类中应用。     

Enzyme diversity in pearl millet (Pennisetum glaucum)

Summary Polymorphism in twelve genes coding for eight enzymes in pearl millet (Pennisetum glaucum (L.) R. Br.): alcohol dehydrogenases (ADH), catalases (CAT), -esterases (EST), glutamate oxaloacetate transaminases (GOT), malate dehydrogenases (MDH), 6-Phosphogluconate dehydrogenases (PGD), phosphoglucoisomerases (PGI) and phosphoglucomutases (PGM), was observed by electrophoresis on 74 cultivated samples and 8 wild samples from West Africa. Six genes: Est A, Adh A, Pgm A, Cat A, Pgi A, Pgd A contain 95% of the total variation. Principal component analyses and discriminant analyses of the 82 samples described by 46 allelic frequencies showed an almost complete separation into 3 groups: wilds, early maturing cultivars and late maturing cultivars. The early group has the highest enzyme diversity, with cultivated millets from Niger showing the most diversity. The high diversity of the early group and its extensive divergence from West-African wild millets suggest, firstly, the existence, elsewhere in Africa of other enzymatically different sources of wild millet, and secondly, the occurrence, prehistorically, of several different domestications. The late group of cultivars has the lowest variability and a relatively low coefficient of differentiation. This relatively homogeneous enzyme structure does not seem to be associated to ecology. A hypothesis is advanced suggesting that West African late-cultivars were derived from a common cultivated early complex. This complex must have been distributed across the Sudanian zone and must have been later sumitted to modifications by limited gene flow with local early maturing cultivars.     

东方田鼠乳酸脱氢酶同工酶的研究

目的研究乳酸脱氢同工酶在3种东方田鼠不同器官的分布.方法以大鼠和小鼠作对照,用聚丙烯酰胺凝胶电泳对3个不同地区的东方田鼠(Microtusfortis)血清、红细胞、肝脏、肾脏、肺中乳酸脱氢酶(LDH)同工酶进行分析.结果东方田鼠血浆中只有LDH5,血清中湖南洞庭湖地区、宁夏青铜峡地区的东方田鼠也只有LDH5,而东北地区的东方田鼠则含有LDH1和LDH5,3个地区的东方田鼠肾脏和肺中都有5种LDH同工酶,肝脏中除东北地区的东方田鼠含5种LDH同工酶外,其余两种东方田鼠均以LDH5为主(LDH5占95%以上).结论东北地区东方田鼠乳酸脱氢酶同工酶谱与其他两地的东方田鼠不相同.