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Gerald A Rosenthal - One of the best experts on this subject based on the ideXlab platform.
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l Canavanine a higher plant insecticidal allelochemical
Amino Acids, 2001Co-Authors: Gerald A RosenthalAbstract:l-Canavanine, l-2-amino-4-(guanidinooxy)butyric acid, is a potentially toxic nonprotein amino acid of certain leguminous plants. Many species are prolific Canavanine producers; they divert enormous nitrogen resource to the storage of this single natural product. Canavanine, a highly effective protective allelochemical, provides a formidable chemical barrier to predation and disease.
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The natural abundance of L-Canavanine, an active anticancer agent, in alfalfa, medicago sativa (L.).
Pharmaceutical biology, 2000Co-Authors: Gerald A Rosenthal, Palesa NkomoAbstract:L-Canavanine, a potentially toxic antimetabolite of L-arginine that is stored by many leguminous plants, has demonstrative antineoplastic activity against a number of animal-bearing carcinomas and cancer cell lines. This investigation evaluated the natural abundance of this anti-cancer compound in commercially available sprouts, and in ten varieties of the seed of alfalfa, Medicago Sativa (L.). Canavanine abundance in commercially grown sprouts varied according to the source; the young plant stored appreciable Canavanine that ranged from 1.3 to 2.4% of the dry matter. Alfalfa seeds were also rich in this nonprotein amino acid as the Canavanine content varied from 1.4 to 1.8% of the dry matter. On average, the tested seeds contained 1.54 ± 0.03% Canavanine. Alfalfa seed Canavanine content was comparable to the levels found in the seeds of representative members of the genus Canavalia , which are amongst the more abundance sources of this antimetabolite.
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The biochemical basis for L-Canavanine tolerance by the tobacco budworm Heliothis virescens (Noctuidae).
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Coromoto Melangeli, Gerald A Rosenthal, Douglas L. DalmanAbstract:The tobacco budworm, Heliothis virescens (Noctuidae), a destructive insect pest, is remarkably resistant to l-Canavanine, l-2-amino-4-(guanidinooxy)butyric acid, an arginine antimetabolite that is a potent insecticide for nonadapted species. H. virescens employs a constitutive enzyme of the larval gut, known trivially as Canavanine hydrolase (CH), to catalyze an irreversible hydrolysis of l-Canavanine to l-homoserine and hydroxyguanidine. As such, it represents a new type of hydrolase, one acting on oxygen–nitrogen bonds (EC 3.13.1.1). This enzyme has been isolated from the excised gut of H. virescens and purified to homogeneity; it exhibits an apparent Km value for l-Canavanine of 1.1 mM and a turnover number of 21.1 μmol·min−1·μmol−1. This enzyme has a mass of 285 kDa and is composed of two subunits with a mass of 50 kDa or 47.5 kDa. CH has a high degree of specificity for l-Canavanine as it cannot function effectively with either l-2-amino-5-(guanidinooxy)pentanoate or l-2-amino-3-(guanidinooxy)propionate, the higher or lower homolog of l-Canavanine, respectively. l-Canavanine derivatives such as methyl-l-Canavanine, or l-canaline and O-ureido-l-homoserine, are not metabolized significantly by CH.
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Insecticidal properties of some derivatives of L-Canavanine
Journal of Agricultural and Food Chemistry, 1995Co-Authors: Gerald A Rosenthal, Douglas L. Dahlman, Peter A. Crooks, Supinan R. Na Phuket, L. S. TrifonovAbstract:The Canavanine derivatives D-Canavanine and L-homoCanavanine as well as the 1-methyl and 1-ethyl esters of L-Canavanine were synthesized and evaluated for biological activity in fifth instar larvae of the tobacco hornworm, Manduca sexta [Sphingidae]. While L-homoCanavanine did not increase intrinsic toxicity, it was as deleterious as L-Canavanine. D-Canavanine was biologically active, as demonstrated by its ability to cause larval edema, but the D-enantiomer had little ability to elicit the larval growth inhibition and pupal deformity which are hallmarks of Canavanine toxicosis and was postulated to be linked to aberrant protein production. The 1-methyl and 1-ethyl esters of L-Canavanine were synthesized to determine if enhancing Canavanine's hydrophobicity might increase its bioavailability. Our experiments revealed that these esters are less toxic than Canavanine ; the ethyl ester disrupted larval growth more than did the methyl analogue.
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Studies of L-Canavanine incorporation into insectan lysozyme.
The Journal of biological chemistry, 1991Co-Authors: Gerald A Rosenthal, D L DahlmanAbstract:Abstract L-Canavanine is incorporated into the lysozyme synthesized, in response to administration of bacterial cell wall materials, by Canavanine-treated larvae of the tobacco hornworm Manduca sexta (Sphingidae). Maximum Canavanine incorporation into M. sexta lysozyme occurs when the larvae are provided 1 mg of Canavanine g-1 fresh body weight. Analysis of Canavanine-containing lysozyme purified from these insects reveals that 21% of the arginine residues are replaced by Canavanine; this residue substitution results in a loss of 49.5% of the catalytic activity. When the larvae are provided 0.5 mg of Canavanine g-1, 16.5% of the arginine residues are substituted by Canavanine and 39.5% of the catalytic activity is lost. Canavanine is also incorporated into the lysozyme induced by Canavanine-treated pupae of the giant silk moth Hyalophora cecropia (Saturnidae). In contrast, replacement of 17% of the arginine in H. cecropia lysozyme by Canavanine fails to affect the catalytic activity. We have determined the primary structure of M. sexta lysozyme and compared it with the primary structure of H. cecropia lysozyme which has been described elsewhere. M. sexta lysozyme has an arginine at positions 23, 42, and 107. H. cecropia contains serine, lysine, and lysine, respectively, at these locations. The ability of incorporated Canavanine to inhibit M. sexta lysozyme activity selectively may result from the fact that replacement of any one of the 3 arginine residues at position 23, 42, or 107 by Canavanine causes the loss of catalytic activity.
Douglas L. Dalman - One of the best experts on this subject based on the ideXlab platform.
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The biochemical basis for L-Canavanine tolerance by the tobacco budworm Heliothis virescens (Noctuidae).
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Coromoto Melangeli, Gerald A Rosenthal, Douglas L. DalmanAbstract:The tobacco budworm, Heliothis virescens (Noctuidae), a destructive insect pest, is remarkably resistant to l-Canavanine, l-2-amino-4-(guanidinooxy)butyric acid, an arginine antimetabolite that is a potent insecticide for nonadapted species. H. virescens employs a constitutive enzyme of the larval gut, known trivially as Canavanine hydrolase (CH), to catalyze an irreversible hydrolysis of l-Canavanine to l-homoserine and hydroxyguanidine. As such, it represents a new type of hydrolase, one acting on oxygen–nitrogen bonds (EC 3.13.1.1). This enzyme has been isolated from the excised gut of H. virescens and purified to homogeneity; it exhibits an apparent Km value for l-Canavanine of 1.1 mM and a turnover number of 21.1 μmol·min−1·μmol−1. This enzyme has a mass of 285 kDa and is composed of two subunits with a mass of 50 kDa or 47.5 kDa. CH has a high degree of specificity for l-Canavanine as it cannot function effectively with either l-2-amino-5-(guanidinooxy)pentanoate or l-2-amino-3-(guanidinooxy)propionate, the higher or lower homolog of l-Canavanine, respectively. l-Canavanine derivatives such as methyl-l-Canavanine, or l-canaline and O-ureido-l-homoserine, are not metabolized significantly by CH.
Coromoto Melangeli - One of the best experts on this subject based on the ideXlab platform.
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The biochemical basis for L-Canavanine tolerance by the tobacco budworm Heliothis virescens (Noctuidae).
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Coromoto Melangeli, Gerald A Rosenthal, Douglas L. DalmanAbstract:The tobacco budworm, Heliothis virescens (Noctuidae), a destructive insect pest, is remarkably resistant to l-Canavanine, l-2-amino-4-(guanidinooxy)butyric acid, an arginine antimetabolite that is a potent insecticide for nonadapted species. H. virescens employs a constitutive enzyme of the larval gut, known trivially as Canavanine hydrolase (CH), to catalyze an irreversible hydrolysis of l-Canavanine to l-homoserine and hydroxyguanidine. As such, it represents a new type of hydrolase, one acting on oxygen–nitrogen bonds (EC 3.13.1.1). This enzyme has been isolated from the excised gut of H. virescens and purified to homogeneity; it exhibits an apparent Km value for l-Canavanine of 1.1 mM and a turnover number of 21.1 μmol·min−1·μmol−1. This enzyme has a mass of 285 kDa and is composed of two subunits with a mass of 50 kDa or 47.5 kDa. CH has a high degree of specificity for l-Canavanine as it cannot function effectively with either l-2-amino-5-(guanidinooxy)pentanoate or l-2-amino-3-(guanidinooxy)propionate, the higher or lower homolog of l-Canavanine, respectively. l-Canavanine derivatives such as methyl-l-Canavanine, or l-canaline and O-ureido-l-homoserine, are not metabolized significantly by CH.
Young Myung Kwon - One of the best experts on this subject based on the ideXlab platform.
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Canavanine synthesis in the in vitro propagated tissues of Canavalia lineata
Plant Cell Reports, 1996Co-Authors: In Doo Hwang, Sang-gu Kim, Young Myung KwonAbstract:Maximum shoot induction from stem explants of Canavalia lineata was obtained with an agar-solidified PC medium containing 10 μM benzylaminopurine and 1 μM naphthaleneacetic acid. Rooting of these in vitro produced shoots was achieved with hormone-free PC medium. Canavanine was produced almost exclusively in the leaves and was not detected in the roots of in vitro propagated C. lineata. To exclude the possibility of imminent translocation of Canavanine from the root to leaf, adventitious roots were induced from leaf explants in PC medium supplemented with I μM kinetin and 20 μM indole-3-acetic acid and subcultured in medium lacking growth regulators, and the roots excised from germinated seedlings were cultured in hormone-free PC medium. All the roots were incapable of accumulation of Canavanine. These results suggest that leaves of C. lineata are the possible site of Canavanine synthesis.
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Canavanine metabolism in tissue cultures of Canavalia lineata
Plant Cell Tissue and Organ Culture, 1996Co-Authors: In Doo Hwang, Sang-gu Kim, Young Myung KwonAbstract:The greening of callus was achieved by modulating the medium's growth regulator concentrations under continuous light. Canavalia lineata (L.) DC. calluses formed chlorophyll when they were exposed to continuous light in the presence of benzylaminopurine and indole-3-acetic acid. Canavanine and canaline were detected in the green callus. But only canaline was detected in the white callus grown in the dark. Feedings of canaline to suspension cultures showed that the green suspended cells were capable of de novo biosynthesis of Canavanine, but the white suspended cells were not. Exogeneously supplied Canavanine was used to produce canaline and homoserine by the white suspended cells. Arginase activity was induced by the addition of arginine or Canavanine to the medium, and canaline reductase activity was induced by the addition of canaline but not with ornithine in the white suspended cells.
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Canavanine synthesis in thein vitro propagated tissues ofCanavalia lineata.
Plant cell reports, 1996Co-Authors: In Doo Hwang, Sang-gu Kim, Young Myung KwonAbstract:Maximum shoot induction from stem explants ofCanavalia lineata was obtained with an agar-solidified PC medium containing 10 μM benzylaminopurine and 1 μM naphthaleneacetic acid. Rooting of thesein vitro produced shoots was achieved with hormone-free PC medium. Canavanine was produced almost exclusively in the leaves and was not detected in the roots ofin vitro propagatedC. lineata. To exclude the possibility of imminent translocation of Canavanine from the root to leaf, adventitious roots were induced from leaf explants in PC medium supplemented with 1 μM kinetin and 20 μM indole-3-acetic acid and subcultured in medium lacking growth regulators, and the roots excised from germinated seedlings were cultured in hormone-free PC medium. All the roots were incapable of accumulation of Canavanine. These results suggest that leaves ofC. lineata are the possible site of Canavanine synthesis.
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Enzyme activities of Canavanine metabolism in Canavalia lineata L. Callus
Journal of Plant Physiology, 1996Co-Authors: In Doo Hwang, Sang-gu Kim, Yi Lee, Jong Seob Lee, Young Myung KwonAbstract:Summary When ornithine, citrulline, and argininosuccinic acid were added to the suspension cultures of Canavalia lineata callus, the arginine content was increased by 47%, 44%, and 75% in white callus, and 24%, 28 %, and 26 % in green callus, respectively. Feeding of canaline or ureidohomoserine increased Canavanine content in green callus but not in white callus. However, when canavaninosuccinic acid was added to the medium, Canavanine was measured in the white and green calli. The activities of ornithine carbamyitransferase, agininosuccinate synthetase, and argininosuccinate lyase were higher in the green callus than in the white callus. The activities of Canavanine-dependent arginase and canaline reductase in the white and green calli were similar. Activity ratios (green/white) of ornithine carbamyitransferase, argininosuccinate synthetase, and argininosuccinate lyase were 1.45, 2.83, and 2.76 in Canavanine accumulation and 1.35, 1.32, and 2.40 in arginine accumulation, respectively. The favorable Cascade effect of Canavanine accumulation was observed in the green callus as compared with the white callus. Among the three enzymes, ureidohomoserine-dependent argininosuccinate synthetase activity of green callus was significantly higher than that of white callus. White callus had one peak of argininosuccinate synthetase activity (ASS-2) and green callus had two peaks of argininosuccinate synthetase activity (ASS-1 and ASS-2) from the DEAE-Sephacel column chromatography. Citrulline-dependent and ureidohomoserine-dependent catalytic activities of argininosuccinate synthetase were detected at the same peaks. It is concluded that the synthesis of Canavanine is regulated through the coordination of ornithine carbamyitransferase, argininosuccinate synthetase, and argininosuccinate lyase.
Douglas L. Dahlman - One of the best experts on this subject based on the ideXlab platform.
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Insecticidal properties of some derivatives of L-Canavanine
Journal of Agricultural and Food Chemistry, 1995Co-Authors: Gerald A Rosenthal, Douglas L. Dahlman, Peter A. Crooks, Supinan R. Na Phuket, L. S. TrifonovAbstract:The Canavanine derivatives D-Canavanine and L-homoCanavanine as well as the 1-methyl and 1-ethyl esters of L-Canavanine were synthesized and evaluated for biological activity in fifth instar larvae of the tobacco hornworm, Manduca sexta [Sphingidae]. While L-homoCanavanine did not increase intrinsic toxicity, it was as deleterious as L-Canavanine. D-Canavanine was biologically active, as demonstrated by its ability to cause larval edema, but the D-enantiomer had little ability to elicit the larval growth inhibition and pupal deformity which are hallmarks of Canavanine toxicosis and was postulated to be linked to aberrant protein production. The 1-methyl and 1-ethyl esters of L-Canavanine were synthesized to determine if enhancing Canavanine's hydrophobicity might increase its bioavailability. Our experiments revealed that these esters are less toxic than Canavanine ; the ethyl ester disrupted larval growth more than did the methyl analogue.
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Incorporation of L-Canavanine into proteins and the expression of its antimetabolic effects
Journal of Agricultural and Food Chemistry, 1991Co-Authors: Gerald A Rosenthal, Douglas L. DahlmanAbstract:L-Canavanine [2-amino-4-(guanidinooxy)butyric acid], a potent arginine antimetabolite, is incorporated readily into the newly synthesized proteins of larvae of the tobacco hornworm, Manduca sexta. Canavanine causes massive developmental aberrations in M. sexta (.)