Organ-specific expression of the stress-related anionic peroxidases in cucumber flowers

The study revealed a marked qualitative and quantitative differences in the pattern of expression of three stress-related cucumber (Cucumis sativus L., cv. Laura) isoperoxidases. Activity staining, as well as the protein gel blot (Western blotting) confirmed that the proteins studied are differentially expressed in both male and female sepals, in male but not in female pedicels and in, pistil. By using antibodies specific to three stress-related peroxidases, one serologically related pistil-specific anionic peroxidase was detected. This specific band had never been observed in other flower organs. Differential appearance of the stress-related peroxidase isoenzymes in both male and female flowers demonstrates that these proteins are developmentally regulated, showing an organ-specific expression.     

Peroxidase Isoenzyme Patterns in Cell Cultures derived from Cotyledon, Stem, Leaf and Fruit from Grapevine (Vitis vinifera cv. Monastrell)

The expression of peroxidase isoenzymes capable of oxidizing4-hydroxystilbenes was studied during the establishment of cellcultures derived from different tissues (cotyledon, stem, leafand fruit) of Vitis vinifera cv. Monastrell vines. This wascarried out in order to elucidate whether different tissuesof the same plant maintain persistent tissue-specific patternsof gene expression during in vitro culture or whether in vitrocultures are characterized by identical patterns of gene expressionirrespective of the tissue's origin. The results illustratedthat both the isozyme patterns and the substrate specificityof the peroxidase activity secreted to the medium are analogousfor the profile of acidic (Prx A) and basic (Prx B) peroxidaseisoenzymes, only quantitative differences being shown in theneutral peroxidase isoenzyme (Prx N) pattern. These resultssuggest that in vitro cultures of grapevines are characterizedby similar patterns of gene expression, no matter what theirtissue of origin.Copyright 1995, 1999 Academic Press Grapevine, vitis vinifera, cell cultures, 4-hydroxystilbene oxidizing peroxidase isoenzyme, substrate specificity     

Sexual differentiation in Asparagus officinalis L.

Summary Using an immunological method we assayed the levels of auxin, abscisic acid and three cytokinins (transzeatin riboside, dihydrozeatin riboside, isopentenyladenosine) in flowers of female and male plants of Asparagus officinalis L. at different stages of development. The largest differences between the sexes were found for auxin: auxin content was found to be about three times higher in young male flowers than in female flowers at a corresponding developmental stage. In order to identify some of the biochemical markers linked to sex differentiation, we also examined peroxidase isoenzyme patterns during flower development. We found five flower-specific peroxidase bands, three of which appear to be localized in the anthers. In young flowers still sexually undifferentiated in their morphology these bands are present in both sexes. They subsequently rapidly disappear in the female flower (approximately at the same time as when anther development is blocked), while they persist for a much longer time in the male. The temporary presence of these peroxidase isoenzymes in female young flowers together with the large difference in auxin content indicate that the stage of the young flower is a crucial moment in the process of sex determination.     

Distribution of the stress-related anionic peroxidases in different cucumber organs

The distribution of the stress-related anionic peroxidase (srPRX) activity was investigated in various organs of cucumber (Cucumis sativus L. cv. Laura) during their development by activity staining and immunoblotting. In shoots, including cotyledon, leaf, stem and tendril, three stress-related peroxidase isoenzymes were present, particularly in old ones. The PRX1 was the only srPRX isoenzyme found in both young and old roots. As fruits became mature, srPRX activity increased dramatically and was particularly enriched in the external parts of the fruit. The PRX1 isoenzyme was highly accumulated in the course of seed germination, while the absence of other two srPRX isoenzymes (PRX2 and PRX3) was recorded. The possible function of the srPRX is discussed, with respect to this spatio-temporal distribution.     

Cytosolic and mitochondrial isoenzymes of branched-chain amino acid aminotransferase during development of the rat.

The isoenzymic forms of branched-chain amino acid aminotransferase in mitochondria of rat tissues were compared with the better-known cytosolic forms in order to find any regular pattern of expression of these isoenzymes during development. Mitochondria of all tissues examined except brain contained only a type-I isoenzyme differing from the cytosolic type-I isoenzyme in heat stability and activation by mercaptoethanol. Foetal and adult brain mitochondria contained isoenzymes type III as well as type I. The large excess of type-I isoenzyme in foetal liver was localized in mitochondria, apparently of haematopoietic cells. The activity of this isoenzyme declined precipitously (by 80%) from day 19 of gestation at the same period and rate as does the volume fraction of haematopoietic cells that are then leaving the liver. Cortisol treatment accelerated the loss of these cells, and proportionally accelerated loss of the mitochondrial isoenzyme I. A development succession of type-I isoenzyme by the unique type II of liver parenchymal cell cytosols could not be demonstrated, since small, about equal, amounts of types I and II were always present in cytosols of foetal and adult liver. Developmental succession of isoenzymes within tissues was limited to cytosols and was demonstrated by the presence of cytosolic isoenzyme III in foetal and newborn skeletal muscle and kidney, organs which contain only isoenzyme I in the adult.     

Changes in the lactate dehydrogenase isoenzyme spectrum during T-lymphocyte differentiation

The pattern of lactate dehydrogenase isoenzyme spectrum changes on different stages of T-lymphocyte differentiation was studied An enriched population of stem cells has LDH-5, 4 and 3 isoenzymes, and much less LDH-2 activity. The isoenzyme pattern of thymic cell precursors consists of LDH-5, 4, 3 and 2. All the five LDH isoenzymes were found in cortical thymocytes. Medullary thymocytes reveal LDH-5, 4 and 3 isoenzymes. T-lymphocytes of peripheral lymphoid organs contain mainly LDH-5 and in a lesser degree LDH-4 activity.     

Peroxidase Isoenzymes in Strawberry Roots Infected with Binucleate Rhizoctonia spp. and their Implication in Disease Resistance

Infection of strawberry plants with binucleate Rhizoctonia spp. results in an increase in peroxidase activity and the appearance of new isoforms of the enzyme. In healthy and diseased roots of two different strawberry genotypes seven peroxidase isoenzymes were found. In healthy strawberry cv. Senga Sengana, which was moderately resistant to infection, four isoenzymes (1, 2, 5, and 6) were found. Moreover the activity of these isoenzymes was increased and three new isoenzymes (3, 4, and 7) were found in infected roots. In the strawberry hybrid 3/2/86/88/R, which is very susceptible to infection, only isoenzyme 2 was present in the roots of healthy plants. Following infection, the activity of isoenzyme 2 was increased and five new isoenzymes (1, 4, 5, 6, and 7) were detectable. The results obtained indicate that strawberry resistance to binucleate Rhizoctonia may be correlated with peroxidase isoenzyme profile with particular reference to isoform 3, which is only present in infected roots of the moderately resistant cv., Senga Sengana.     

The development of glutathione S-transferase and glutathione peroxidase activities in human lung

The development of glutathione S-transferase and glutathione peroxidase activities has been studied in human lung cytosols. Whilst no clear change in glutathione peroxidase activity was identified, expression of the acidic glutathione S-transferase isoenzyme decreased markedly after 15 weeks of gestation so that at birth the level of activity of this isoenzyme was only about 20% of that in samples obtained during the first trimester. Basic glutathione S-transferase isoenzymes were weakly expressed during development and usually comprised less than 10% of cytosolic activity. Ion-exchange studies identified several basic isoenzymes that may correspond to the alpha, beta, gamma, delta and epsilon set previously identified in liver. Weak expression of apparently near-neutral isoenzymes was also detected; they were detected in only a few cytosols.     

Characterization of the pectin methylesterase-like gene AtPME3: a new member of a gene family comprising at least 12 genes in Arabidopsis thaliana

Pectin demethylesterification appears to be catalysed by a number of pectin methylesterase (PME) isoenzymes in higher plant species. In order to better define the biological role of these isoenzymes in plant cell growth and differentiation, we undertook molecular studies on the PME-encoding genes in Arabidopsis thaliana. In this paper, we report the characterization of AtPME3, a new PME-related gene of 4 kb in length that we have mapped on Chromosome III. AtPME3 encodes a putative mature PME-related isoenzyme of 34 kDa with a basic isoelectric point. Since the extent of the gene family encoding PME in higher plant species is still unknown, we resorted to the use of degenerate primers designed from several well-known consensus regions to identify new PME-related genes in the genome of Arabidopsis. Our results, in combination with several known expressed sequences tags (ESTs), indicate that the Arabidopsis genome contains at least 12 PME-related genes. Consequently, a method of systematic gene expression analysis has been applied in order to discern the expression pattern of these 12 genes throughout the plant at the floral stage. Whereas most of these genes appeared to be more or less ubiquitously expressed throughout the plant, several genes are distinguishable by their strikingly specific expression in certain organs. The present data bring a new insight into the role of specific PME-related genes in flower and root development.     

Indole-3-acetic acid content and glutamine synthetase activity in the pericarp,and peroxidase activity and isoenzymes in the meso- and exocarp of growing peach fruits

The indole-3-acetic acid (IAA) content in peach pericarp (Prunus persica L. Batsch cv. Merry) was highest at early stage I of development (～200 ng/g fresh wt), decreased to the lowest level during stage II, and rose again at stage III to 60–70 ng/g fresh wt. High activity of glutamine synthetase was found in the pericarp during stage I. The soluble peroxidase activity was highest in the meso- and exocarp at stage II, and isoenzymatic changes in this fraction corresponded to the transition from cationic isoenzymes, predominant at stage I, to anionic isoenzymes at stage III. The ionically bound peroxidase activity in these tissues was highest at stage I. The three developmental stages showed marked differences in auxin content and enzyme activities; for peroxidases these changes reflect a developmental expression pattern for the isoenzymes.     

“葡萄状核桃”和普通核桃的过氧化物酶同工酶的比较研究

用聚丙烯酰胺凝胶电泳技术测定了葡萄状核桃和普通核桃６种组织的过氧化物酶同工酶。分析比较了两种核酶谱和酶活性的异同。结果表明,葡萄状核桃除当年生果枝外,其它各组织中的过氧化物酶活性均低于普通核桃。葡萄状核桃雄花轴,雌花和雄花中酶带的数目也比普通核桃相应组织为少。     

黄瓜雄花形成过程中心皮的发育

黄瓜(Cucumis sativus L)为重要的经济作物,雌雄同株异花,是研究植物性别分化的经典材料。人们对黄瓜性别分化进行了广泛的研究。Astmon和Galun,任吉君和王艳对黄瓜性别分化的形态特征和器官发生进行了初步研究,表明黄瓜单性花分化和发育过程中经历了无性期、两性期和单性期,最     

黄瓜雄花形成过程中心皮的发育

黄瓜(Cucumis sativus L.)为重要的经济作物,雌雄同株异花,是研究植物性别分化的经典材料。人们对黄瓜性别分化进行了广泛的研究。Astmon和Galun、任吉君和王艳对黄瓜性别分化的形态特征和器官发生进行了初步研究,表明黄瓜单性花分化和发育过程中经历了无性期、两性期和单性期,最终只有一种性别的性器官原基发育成有功能的性器官,从而形成单性花,而对单性花中未形成有功能器官的相反性别原基的研究报道甚少。我们对雄花发育过程进行了连续的形态学分析,并对不同时期雄花中的心皮进行了细胞计数和同工酶电泳分析,以期从性器官发育的角度探讨黄瓜性别表现的机理。     

Correlation between development of female flower buds and expression of the CS-ACS2 gene in cucumber plants

Ethylene plays a key role in sex determination of cucumber flowers. Gynoecious cucumber shoots produce more ethylene than monoecious shoots. Because monoecious cucumbers produce both male and female flower buds in the shoot apex and because the relative proportions of male and female flowers vary due to growing conditions, the question arises as to whether the regulation of ethylene biosynthesis in each flower bud determines the sex of the flower. Therefore, the expression of a 1-aminocyclopropane-1-carboxylic acid synthase gene, CS-ACS2, was examined in cucumber flower buds at different stages of development. The results revealed that CS-ACS2 mRNA began to accumulate just beneath the pistil primordia of flower buds at the bisexual stage, but was not detected prior to the formation of the pistil primordia. In buds determined to develop as female flowers, CS-ACS2 mRNA continued to accumulate in the central region of the developing ovary where ovules and placenta form. In gynoecious cucumber plants that produce only female flowers, accumulation of CS-ACS2 mRNA was detected in all flower buds at the bisexual stage and at later developmental stages. In monoecious cucumber, flower buds situated on some nodes accumulated CS-ACS2 mRNA, but others did not. The proportion of male and female flowers in monoecious cucumbers varied depending on the growth conditions, but was correlated with changes in accumulation of CS-ACS2 mRNA in flower buds. These results demonstrate that CS-ACS2-mediated biosynthesis of ethylene in individual flower buds is associated with the differentiation and development of female flowers.     

Effect of drought on proteins and isoenzymes in rice during germination

Two drought tolerant varieties TKM-1 and TKM-2 and two drought susceptible varieties Jaya and Improved Sabarmati of rice were studied for soluble protein pattern and isoenzymes of malate dehydrogenase, glutamate dehydrogenase, esterase and peroxidase during germination at different water stress. MDH, GDH and esterase patterns were not affected, but the soluble proteins were changed. Peroxidase isoenzyme pattern from drought tolerant and susceptible varieties showed characteristic differences. The intensity of bands with higher electrophoretic mobility decreased in Jaya and Improved Sabarmati while in TKM-1 and TKM-2 the intensity of these bands did not change much after 72 hr water stress. In shoots of Jaya and Improved Sabarmati, the activity of the peroxidase isoenzymes decreased more than in TKM-1 and TKM-2 shoots with increase in water stress.