Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nature of secretion products forming the pellicle of the dry-type stigma surface has been investigated in Brassica by an electron-microscopic cytochemical study. In order to determine whether the pellicle is organized like a membrane, we used a series of cytochemical methods to visualize cell membranes. Three groups of techniques presenting different degrees of specificity in terms of cell surface markers have been used: non-specific labelling of cell-surface components, characterization of glycoconjugates and localization of enzymic activities. We demonstrated that the pellicle of Brassica stigmas, although not possessing a trilamellar structure, presents numerous characteristics encountered in biological membranes. In particular, it possesses cytochemically demonstrable enzyme activities, including ATPase and adenylate cyclase, whose role remains to be elucidated in relation to the pollen-stigma interactions.
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PMID:Organization of stigma surface components in Brassica: a cytochemical study. 294 4

The localization of Ca2+ and Ca(2+)-ATPase activity in the unpollinated pistil of Petunia hybrida has been studied. Free or loosely sequestered Ca2+ ions have been found: (1) in the stigma exudate, (2) in the pistil transmitting tract, (3) on the surface of ovule, (4) in the cell wall of the embryo sac. The sites of Ca2+ sequestration in the transmitting cells were the plastids and vacuoles. In some cells, the Ca2+ ions were associated with the tonoplast and plasmalemma underlying the transverse walls which connect the transmitting cells. The sites of particular accumulation of Ca2+ were the surfaces of the placenta and of the ovule. In the ovule, numerous precipitates occurred in the extended walls connecting the embryo sac with the cells of the nucellus. Ca(2+)-ATPase was commonly localized on the plasmalemma (1) of the cells of the transmitting tract of the stigma and style, (2) of the placenta and (3) of the somatic cells of the ovule. The plasmalemma of the embryo sac cells was nearly completely devoid of the reaction product.
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PMID:Calcium in pollen-pistil interaction in Petunia hybrida Hort. II. Localization of Ca2+ ions and Ca(2+)-ATPase in unpollinated pistil. 755 73

Calcium regulates diverse developmental processes in plants through the action of calmodulin. A cDNA expression library from developing anthers of tobacco was screened with 35S-labeled calmodulin to isolate cDNAs encoding calmodulin-binding proteins. Among several clones isolated, a kinesin-like gene (TCK1) that encodes a calmodulin-binding kinesin-like protein was obtained. The TCK1 cDNA encodes a protein with 1265 amino acid residues. Its structural features are very similar to those of known kinesin heavy chains and kinesin-like proteins from plants and animals, with one distinct exception. Unlike other known kinesin-like proteins, TCK1 contains a calmodulin-binding domain which distinguishes it from all other known kinesin genes. Escherichia coli-expressed TCK1 binds calmodulin in a Ca(2+)-dependent manner. In addition to the presence of a calmodulin-binding domain at the carboxyl terminal, it also has a leucine zipper motif in the stalk region. The amino acid sequence at the carboxyl terminal of TCK1 has striking homology with the mechanochemical motor domain of kinesins. The motor domain has ATPase activity that is stimulated by microtubules. Southern blot analysis revealed that TCK1 is coded by a single gene. Expression studies indicated that TCK1 is expressed in all of the tissues tested. Its expression is highest in the stigma and anther, especially during the early stages of anther development. Our results suggest that Ca2+/calmodulin may play an important role in the function of this microtubule-associated motor protein and may be involved in the regulation of microtubule-based intracellular transport.
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PMID:A novel kinesin-like protein with a calmodulin-binding domain. 870 62

Ultracytochemical localization of adenosine triphosphatase (ATPase) activity in stigmas, pollens and pollen tubes of Fagopyrum esculentum was performed with the cytochemical method of lead phosphate precipitation. The results were as follows: (1) Lower activities of ATPase appeared in stigma cells at 0.5 hour after compatible and incompatible pollination. Stigma surface and pollen grains attached on stigma showed higher ATPase activities after compatible pollination and lower or no activities after incompatible pollination at 0.5 hour. ATPase localized on endoplasmic reticula and sperm cell in pollen grain. (2) Lower ATPase activities appeared both in stigma cells and pollen tubes in style at 1.5 hours after incompatible pollination. Pollen tube stopped growing and the degeneration of its cytoplasma began; on the contrary, at 1.5 hours after compatible pollination, higher ATPase activities were detected both in stigma cells and pollen tube in style. ATPase localized mainly on plasmolemma, in cytoplasmic matrix of stigma cells and in mitochondria, dictyosome, plastid envelop, and on the wall of pollen tube as well. The present study indicated that the stop of pollen tube growth after self-incompatibility of Fagopyrum esculentum resulted not only from the nutrient starvation of pollen tube, but also from its metabolic disorder in incompatible style.
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PMID:[The ultracytochemical localization of ATPase activity in pollen tube and stigma of Fagopyrum esculentum after compatible and incompatible pollination]. 1534 17

The modifying effects of Crocus sativus (CS) stigma extract on neurobehavioral activities, malondialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase, glutathione reductase, glutathione S-transferase, superoxide dismutase (SOD), catalase (CAT), and Na(+),K(+)-ATPase activities, and glutamate (Glu) and aspartate (Asp) content were examined in the middle cerebral artery (MCA) occlusion (MCAO) model of acute cerebral ischemia in rats. The right MCA of male Wistar rats was occluded for 2 hours using intraluminal 4-0 monofilament, and reperfusion was allowed for 22 hours. MCAO caused significant depletion in the contents of GSH and its dependent enzymes while significant elevation of MDA, Glu, and Asp. The activities of Na(+),K(+)-ATPase, SOD, and CAT were decreased significantly by MCAO. The neurobehavioral activities (grip strength, spontaneous motor activity, and motor coordination) were also decreased significantly in the MCAO group. All the alterations induced by ischemia were significantly attenuated by pretreatment of CS (100 mg/kg of body weight, p.o.) 7 days before the induction of MCAO and correlated well with histopathology by decreasing the neuronal cell death following MCAO and reperfusion. The present results may suggest the effectiveness of CS in focal ischemia most probably by virtue of its antioxidant property.
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PMID:Effect of Saffron (Crocus sativus) on neurobehavioral and neurochemical changes in cerebral ischemia in rats. 1682 11

To allow successful germination and growth of a pollen tube, mature and dehydrated pollen grains (PGs) take up water and have to adjust their turgor pressure according to the water potential of the surrounding stigma surface. The turgor pressure of PGs of lily (Lilium longiflorum) was measured with a modified pressure probe for simultaneous recordings of turgor pressure and membrane potential to investigate the relation between water and electrogenic ion transport in osmoregulation. Upon hyperosmolar shock, the turgor pressure decreased, and the plasma membrane (PM) hyperpolarizes in parallel, whereas depolarization of the PM was observed with hypoosmolar treatment. An acidification and alkalinization of the external medium was monitored after hyper- and hypoosmotic treatments, respectively, and pH changes were blocked by vanadate, indicating a putative role of the PM H(+) ATPase. Indeed, an increase in PM-associated 14-3-3 proteins and an increase in PM H(+) ATPase activity were detected in PGs challenged by hyperosmolar medium. We therefore suggest that in PGs the PM H(+) ATPase via modulation of its activity by 14-3-3 proteins is involved in the regulation of turgor pressure.
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PMID:Osmoregulation in Lilium pollen grains occurs via modulation of the plasma membrane H+ ATPase activity by 14-3-3 proteins. 2097 94

Early embryogenesis in Arabidopsis (Arabidopsis thaliana) is distinguished by a predictable pattern of cell divisions and is a good system for investigating mechanisms of developmental pattern formation. Here, we identified a gene called LONO1 (LNO1) in Arabidopsis in which mutations can abolish the first asymmetrical cell division of the zygote, alter planes and number of cell divisions in early embryogenesis, and eventually arrest embryo development. LNO1 is highly expressed in anthers of flower buds, stigma papilla of open flowers, and embryo and endosperm during early embryogenesis, which is correlated with its functions in reproductive development. The homozygous lno1-1 seed is not viable. LNO1, a homolog of the nucleoporin NUP214 in human (Homo sapiens) and Nup159 in yeast (Saccharomyces cerevisiae), encodes a nucleoporin protein containing phenylalanine-glycine repeats in Arabidopsis. We demonstrate that LNO1 can functionally complement the defect in the yeast temperature-sensitive nucleoporin mutant nup159. We show that LNO1 specifically interacts with the Arabidopsis DEAD-box helicase/ATPase LOS4 in the yeast two-hybrid assay. Furthermore, mutations in AtGLE1, an Arabidopsis homolog of the yeast Gle1 involved in the same poly(A) mRNA export pathway as Nup159, also result in seed abortion. Our results suggest that LNO1 is a component of the nuclear pore complex required for mature mRNA export from the nucleus to the cytoplasm, which makes LNO1 essential for embryogenesis and seed viability in Arabidopsis.
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PMID:LONO1 encoding a nucleoporin is required for embryogenesis and seed viability in Arabidopsis. 2289 97