scholarly journals STUDIES ON CARBOHYDRATE-METABOLIZING ENZYMES. THE HYDROLYSIS OF α-GLUCOSIDES, INCLUDING NIGEROSE, BY EXTRACTS OF ALFALFA AND OTHER HIGHER PLANTS

1965 ◽  
Vol 94 (3) ◽  
pp. 783-789 ◽  
Author(s):  
DH HUTSON ◽  
DJ MANNERS
Keyword(s):  
Higher Plants ◽  
Metabolizing Enzymes ◽  
Hydrolysis Of

Chemistry of oxylipin pathways in marine diatoms

2007 ◽  
Vol 79 (4) ◽  
pp. 481-490 ◽  
Author(s):  
Angelo Fontana ◽  
Giuliana d'Ippolito ◽  
Adele Cutignano ◽  
Antonio Miralto ◽  
Adrianna Ianora ◽  
...  
Keyword(s):  
Higher Plants ◽  
Larval Growth ◽  
Marine Macroalgae ◽  
High Concentration ◽  
Marine Diatoms ◽  
Fatty Acid Derivatives ◽  
The Family ◽  
Hydrolysis Of ◽  
Catalyzed Oxidation

Oxylipins are important signal transduction molecules widely distributed in animals and plants where they regulate a variety of events associated with physiological and pathological processes. The family embraces several different metabolites that share a common origin from the oxygenase-catalyzed oxidation of polyunsaturated fatty acids. The biological role of these compounds has been especially studied in mammalians and higher plants, although a varied and very high concentration of these products has also been reported from marine macroalgae. This article gives a summary of our results concerning the oxylipin chemistry of marine diatoms, a major class of planktonic microalgae that discourage predation from their natural grazers, zooplanktonic copepods, using chemical warfare. These apparently harmless microscopic cells produce a plethora of oxylipins, including short-chain unsaturated aldehydes, hydroxyl-, keto-, and epoxyhydroxy fatty acid derivatives, that induce reproductive failure in copepods through abortions, congenital malformations, and reduced larval growth. The biochemical process involved in the production of these compounds shows a simple regulation based on decompartmentation and mixing of preexisting enzymes and requires hydrolysis of chloroplast-derived glycolipids to feed the downstream activities of C16 and C20 lipoxygenases.

scholarly journals Multi-molecular tracers of terrestrial carbon transfer across the pan-Arctic: comparison of hydrolyzable components with plant wax lipids and lignin phenols

2015 ◽  
Vol 12 (15) ◽  
pp. 4841-4860 ◽  
Author(s):  
X. Feng ◽  
Ö. Gustafsson ◽  
R. M. Holmes ◽  
J. E. Vonk ◽  
B. E. van Dongen ◽  
...  
Keyword(s):  
Higher Plants ◽  
River Sediments ◽  
Molecular Composition ◽  
Benchmark Assessment ◽  
Lignin Phenols ◽  
Carbon Transfer ◽  
North American Arctic ◽  
Arctic Rivers ◽  
Hydrolysis Of ◽  
Plant Wax

Abstract. Hydrolyzable organic carbon (OC) comprises a significant component of sedimentary particulate matter transferred from land into oceans via rivers. Its abundance and nature are however not well studied in Arctic river systems, and yet may represent an important pool of carbon whose fate remains unclear in the context of mobilization and related processes associated with a changing climate. Here, we examine the molecular composition and source of hydrolyzable compounds isolated from sedimentary particles derived from nine rivers across the pan-Arctic. Bound fatty acids (b-FAs), hydroxy FAs, n-alkane-α,ω-dioic acids (DAs) and phenols were the major components released upon hydrolysis of these sediments. Among them, b-FAs received considerable inputs from bacterial and/or algal sources, whereas ω-hydroxy FAs, mid-chain substituted acids, DAs, and hydrolyzable phenols were mainly derived from cutin and suberin of higher plants. We further compared the distribution and fate of suberin- and cutin-derived compounds with those of other terrestrial biomarkers (plant wax lipids and lignin phenols) from the same Arctic river sedimentary particles and conducted a benchmark assessment of several biomarker-based indicators of OC source and extent of degradation. While suberin-specific biomarkers were positively correlated with plant-derived high-molecular-weight (HMW) FAs, lignin phenols were correlated with cutin-derived compounds. These correlations suggest that, similar to leaf-derived cutin, lignin was mainly derived from litter and surface soil horizons, whereas suberin and HMW FAs incorporated significant inputs from belowground sources (roots and deeper soil). This conclusion is supported by the negative correlation between lignin phenols and the ratio of suberin-to-cutin biomarkers. Furthermore, the molecular composition of investigated biomarkers differed between Eurasian and North American Arctic rivers: while lignin dominated in the terrestrial OC of Eurasian river sediments, hydrolyzable OC represented a much larger fraction in the sedimentary particles from Colville River. Hence, studies exclusively focusing on either plant wax lipids or lignin phenols will not be able to fully unravel the mobilization and fate of bound OC in Arctic rivers. More comprehensive, multi-molecular investigations are needed to better constrain the land–ocean transfer of carbon in the changing Arctic, including further research on the degradation and transfer of both free and bound components in Arctic river sediments.

Influence of dopamine on cyclic nucleotide enzymes in bovine retinal membrane fractions

1993 ◽  
Vol 10 (6) ◽  
pp. 991-996 ◽  
Author(s):  
Ari Sitaramayya ◽  
Lorraine Lombardi ◽  
Alexander Margulis
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Cyclic Nucleotide ◽  
D2 Receptors ◽  
D1 Receptors ◽  
Metabolizing Enzymes ◽  
D2 Agonist ◽  
Hydrolysis Of ◽  
Cyclic Amp Synthesis

AbstractDopamine is a major neurotransmitter and neuromodulator in vertebrate retina. Although its pharmacological and physiological actions are well understood, the biochemical mechanisms of its signal transduction are less clear. Acting via D1 receptors, dopamine was shown to increase cyclic AMP levels in intact retina and to activate adenylate cyclase in retinal homogenates. The action via activation of D2 receptors is controversial: it was reported to decrease cyclic AMP levels in intact retina but inhibition of cyclase could not be demonstrated in retinal homogenates; also it was reported to activate rod outer segment cyclic GMP phosphodiesterase in vitro but did not decrease cyclic GMP levels in aspartate-treated retinas. We made an attempt to fractionate bovine retinal membranes and to investigate the effects of dopamine, via Dl and D2 receptors, on the synthesis and hydrolysis of cyclic AMP and cyclic GMP. Activation of cyclic AMP synthesis was noted in all fractions, but no effects were evident on cyclic nucleotide hydrolysis or cyclic GMP synthesis in any fraction. Also, D2 agonist did not inhibit cyclic AMP synthesis. These observations suggest that D2 receptors may not be directly coupled to cyclic nucleotide metabolizing enzymes in bovine retina.

scholarly journals The formation of glycoproteins in tissues of higher plants. Specific labelling with d-[l-14C]glucosamine

1971 ◽  
Vol 125 (4) ◽  
pp. 999-1008 ◽  
Author(s):  
R. M. Roberts ◽  
A. B. Connor ◽  
J. J. Cetorelli
Keyword(s):  
Potassium Hydroxide ◽  
Broad Bean ◽  
Higher Plants ◽  
Lemna Minor ◽  
Amino Sugar ◽  
Acer Pseudoplatanus ◽  
Radioactive Product ◽  
Insoluble Compounds ◽  
Hydrolysis Of ◽  
Specific Labelling

1. Radioactivity from d-[l-14C]glucosamine is incorporated into ethanol-insoluble compounds of high molecular weight in a number of plant tissues, including roots of corn (Zea mays), callus cells of sycamore (Acer pseudoplatanus), axenic cultures of duckweed (Lemna minor) and germinating seedlings of corn, broad bean (Vicia faba) and barley (Hordeum vulgare). 2. Except in the case of Lemna, where some of the radioactivity was recovered in glucose, hydrolysis of these ethanol-insoluble materials with acid released [14C]glucosamine as the major radioactive product. 3. The labelled compounds isolated from Zea roots and the Acer cells are believed to be glycoproteins rather than polysaccharides on the basis of their solubility properties, their charge characteristics and their susceptibility to hydrolysis by 0.5m-potassium hydroxide and by the proteases trypsin and Pronase. Further, radioactive peptides were isolated and purified after Pronase treatment and shown to contain glucosamine as well as a number of amino acids. 4. The experiments therefore indicate that d-[14C]glucosamine can be used as a specific precursor of the amino sugar units of plant as well as animal glycoproteins.

Toxicokinetics and Hydrolysis of Artelinate and Artesunate in Malaria-Infected Rats

2005 ◽  
Vol 24 (4) ◽  
pp. 241-250 ◽  
Author(s):  
Qigui Li ◽  
Lisa H. Xie ◽  
Yuanzheng Si ◽  
Elaine Wong ◽  
Ravi Upadhyay ◽  
...  
Keyword(s):  
Drug Exposure ◽  
Enterohepatic Circulation ◽  
Metabolizing Enzymes ◽  
Antimalarial Agents ◽  
Elimination Half ◽  
Conversion Rates ◽  
Daily Dose ◽  
Exposure Levels ◽  
Distribution Studies ◽  
Hydrolysis Of

Comparative toxicokinetic (TK) and hydrolysis studies of intravenously administered two new antimalarial agents, artelinate (AL) and artesunate (AS), were performed in malaria-infected rats using three daily equimolar doses (96 μmoles/kg). The TK evaluation was related to select one drug for severe malaria treatment in U.S. Army. Drug concentration of AS with daily dose of 36.7 mg/kg was one-third less on day 3 than on day 1, which resembled its active metabolite, dihydroartemisinin (DHA), suggesting an autoinduction of hepatic drug-metabolizing enzymes for AS. The results were similar to other artemisinin drugs, but not for AL. TK parameters of AL were very comparable from day 1 to day 3 at same AS molecular dose at 40.6 mg/kg. AS is the prodrug of DHA with the DHA/AS ratio of 5.26 compared to the ratio of 0.01 for DHA/AL. Other TK parameters revealed that the total AUC1–3 days (84.4 μg · h ml−1) of AL was fivefold higher than that of AS (15.7 mu;g h ml−1 of AS plus DHA). The elimination half-life of AL (7.1 h) was much longer than that of AS (0.36 h) or DHA (0.72 h). The remarkable alteration of the TK shape of AL may be caused by poor conversion rates to DHA and an enterohepatic circulation, which is confirmed by the present TK and tissue distribution studies. Compared to AS, higher drug exposure levels and longer exposure time of AL in the rat blood may be the cause of its increased toxicity.

BIOSYNTHESIS AND DEGRADATION OF STARCH IN HIGHER PLANTS

2020 ◽  
Author(s):  
Lungwani Muungo
Keyword(s):  
Higher Plants ◽  
Starch Biosynthesis ◽  
Metabolizing Enzymes ◽  
Transitory Starch ◽  
Leaf Tissues ◽  
Cellular Compartments

Numerous reviews on starch biosynthesis and degradation have appeared inthe 1980s (4, 23, 39, 40, 51, 73, 100, 101, 124, 125). Here we updateestablished concepts and emphasize three topics that we consider to now meritreexamination: the significance of enzyme multiplicity, a comparison ofdegradation of reserve and transitory starch, and the localization of starchdegrading enzymes in starch-free cellular compartments of leaf tissues. Westress the cell physiological aspects of starch metabolizing enzymes.

scholarly journals ANALYSIS OF FLAVONES C-GLYCOSIDES AND AND STEPWISE HYDROLYSIS OF THEIR ACETATES IN THE LEAVES OF RUBUS CHAMAEMORUS L.

2021 ◽  
pp. 257-265
Author(s):  
Andrey Kennet Whaley ◽  
Anastasiya Olegovna Ponkratova ◽  
Anastasiya Andreyevna Orlova ◽  
Evgeni Borisovich Serebryakov ◽  
Stanislav Ivanovich Selivanov ◽  
...  
Keyword(s):  
Biological Activity ◽  
Hplc Analysis ◽  
Higher Plants ◽  
Two Dimensional ◽  
Cardiotonic Activity ◽  
Hydrolysis Products ◽  
Rubus Chamaemorus ◽  
Growing Conditions ◽  
First Time ◽  
Hydrolysis Of

The C-glycoside embinin and its mono- and diacetate derivatives have immunotropic and cardiotonic activity, which makes the search for plants that contain them interesting. Embinin and its acetate derivatives were previously isolated only from some plants of the genus Iris, the habitat and growing conditions of which are very different from those of the genus Rubus. As a result of the study, the structure of seven C-glycosides, embinin derivatives, isolated from the leaves of Rubus chamaemorus L. (Rosaceae) was established. Using HR-ESI-MS, HPLC-MS, as well as one- and two-dimensional NMR spectroscopy, the structure of three substances isolated in individual form was established: embinin (1) and its diacetyl derivatives – 2''',3'''-diacetylembinin (5) and 3''',4'''-diacetylembinin (7). The method of stepwise hydrolysis of C-glycoside acetate residues proposed in this study, followed by HPLC analysis of the resulting hydrolysis products, made it possible to establish the structure of minor flavone C-glycosides contained in the leaves of Rubus chamaemorus L.: 2'''-acetylembinin (2), 3'''-acetylembinin (3), 4'''-acetylembinin (4) and 2''',4'''-diacetylembinin (6). All these compounds were found in the leaves of Rubus chamaemorus L. for the first time. The C-glycosides - embinin and its acetate derivatives are rare metabolites of higher plants, the presence of which is determined by the peculiarity of their physiology, and the biological activity determines the prospects for medical use.

scholarly journals Substrate specific hydrolysis of aromatic and aromatic-aliphatic esters in orchid tissue cultures

2014 ◽  
Vol 62 (1-2) ◽  
pp. 21-23 ◽  
Author(s):  
Agnieszka Mironowicz ◽  
Krystyna Kukułczanka ◽  
Antoni Siewiński
Keyword(s):  
Molecular Weight ◽  
Higher Plants ◽  
Methyl Esters ◽  
Chemical Compounds ◽  
Aliphatic Alcohols ◽  
Low Molecular Weight ◽  
Tissue Cultures ◽  
Aliphatic Acids ◽  
Aliphatic Esters ◽  
Hydrolysis Of

We found that tissue cultures of higher plants were able, similarly as microorganisms, to transform low-molecular-weight chemical compounds. In tissue cultures of orchids (<i>Cymbidium</i> 'Saint Pierre' and <i>Dendrobium phalaenopsis</i>) acetates of phenols and aromatic-aliphatic alcohols were hydrolyzed, whereas methyl esters of aromatic and aromatic-aliphatic acids did not undergo this reaction. Acetates of racemic aromatic-aliphatic alcohols were hydrolyzed with distinct enantiospecificity.

scholarly journals Mutations in Phosphoinositide Metabolizing Enzymes and Human Disease

Physiology ◽  
2009 ◽  
Vol 24 (1) ◽  
pp. 8-16 ◽  
Author(s):  
Heather J. McCrea ◽  
Pietro De Camilli
Keyword(s):  
Calcium Release ◽  
Signal Transduction Pathway ◽  
Therapeutic Interventions ◽  
Cellular Functions ◽  
Metabolizing Enzymes ◽  
Surface Receptors ◽  
Kinase C ◽  
Messenger Molecules ◽  
Stimulus Secretion Coupling ◽  
Hydrolysis Of

Phosphoinositides are implicated in the regulation of a wide variety of cellular functions. Their importance in cellular and organismal physiology is underscored by the growing number of human diseases linked to perturbation of kinases and phosphatases that catalyze interconversion from one phosphoinositide to another. Many such enzymes are attractive targets for therapeutic interventions. Here, we review diseases linked to inheritable or somatic mutations of these enzymes. Phosphatidylinositol (PtdIns), a membrane phospholipid, can be reversibly phosphorylated at the 3, 4, and 5 positions of the inositol ring to generate seven phosphoinositides [PI3P, PI4P, PI5P, PI( 3 , 4 )P2, PI( 4 , 5 )P2, PI( 3 , 5 )P2, and PI( 3 , 4 , 5 )P3] (FIGURE 1A ). The importance of this metabolism in cell regulation was first established in the context of studies on stimulus-secretion coupling. It was found that many stimuli that trigger secretion also trigger enhanced turnover of PtdIns and phosphoinositides ( 42 ). Subsequently, it became clear that phospholipase C-dependent hydrolysis of PI( 4 , 5 )P2 to generate the second messenger molecules diacyl glycerol and Ins( 1 , 4 , 5 )P3 (IP3) is a mechanism through which many cell surface receptors, including many receptors that stimulate secretion, transduce their signals ( 10 ). Diacyl glycerol binds and regulates protein kinase C and a variety of other effectors, whereas IP3 triggers calcium release from the endoplasmic reticulum ( 10 , 42 ). In another signal transduction pathway, PI( 4 , 5 )P2 is cleaved by phospholipase A2 to generate arachidonic acid, a precursor of many signaling molecules.

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