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George H Dalrymple - One of the best experts on this subject based on the ideXlab platform.

  • seasonal activity and road mortality of the snakes of the pa hay okee wetlands of everglades national park usa
    Biological Conservation, 1992
    Co-Authors: Frank S Bernardino, George H Dalrymple
    Abstract:

    Abstract The composition and activity of the snake community of the Pa-hay-okee wetlands of Everglades National Park is described. The study was conducted in February and March 1986 and from February 1987 to January 1989. A total of 1172 individuals of 16 taxa were observed, with Thamnophis sauritus, T. sirtalis, Nerodia fasciata pictiventris and Agkistrodon Piscivorus representing 89·2% of the total sample. The seasonal activity of the snakes was closely related to fluctuations in the water table. Periods of greatest snake activity coincided with the periods of greatest human visitation. Seventy-three percent of all snakes observed on the park's main road were either injured or dead. Management recommendations are provided to minimize loss.

Bruno Lomonte - One of the best experts on this subject based on the ideXlab platform.

  • identification of the myotoxic site of the lys49 phospholipase a2 from Agkistrodon Piscivorus Piscivorus snake venom synthetic c terminal peptides from lys49 but not from asp49 myotoxins exert membrane damaging activities
    Toxicon, 2001
    Co-Authors: Carlos E Nunez, Yamileth Angulo, Bruno Lomonte
    Abstract:

    Group II phospholipase A(2) (PLA(2)) myotoxins found in the venoms of Crotalidae snakes can be divided into 'Asp49' and 'Lys49' isoforms, the latter being considered catalytically-inactive variants. Previous studies on one Lys49 isoform, myotoxin II from Bothrops asper, indicated that its myotoxic activity is due to the presence of a short cationic/hydrophobic sequence (115-129) near its C-terminus, which displays membrane-damaging properties. Since the C-terminal region of different group II PLA(2) myotoxins presents considerable sequence variability, synthetic peptides homologous to region 115-129 of myotoxin II, but corresponding to B. asper myotoxin III (Asp49), Agkistrodon Piscivorus Piscivorus Asp49 PLA(2) and Lys49 PLA(2), were studied to determine the possible functional relevance of such region for the toxic activities of these proteins. Results showed that both Lys49-derived peptides (p-BaK49 and p-AppK49) were able to lyse skeletal muscle C2C12 cells in culture, and to induce edema in the mouse footpad assay. Moreover, p-AppK49, which showed a markedly stronger cytotoxic potency than p-BaK49, additionally induced skeletal muscle necrosis when injected into mice. These observations unequivocally identify the sequence 115-129 (KKYKAYFKLKCKK) of the Lys49 PLA(2) of A. p. Piscivorus as containing the key structural determinants needed for myotoxicity, and represent the first report of an unmodified, PLA(2)-derived short synthetic peptide with the ability to reproduce this effect of a parent toxin in vivo. On the other hand, the two Asp49-derived peptides did not show any toxic effects in vitro or in vivo, even at high concentrations. These findings suggests that Lys49 and Asp49 group II PLA(2)s might exert their myotoxic actions through different molecular mechanisms, by implying that the latter may not utilize their C-terminal regions as main membrane-destabilizing elements.

Takashi Morita - One of the best experts on this subject based on the ideXlab platform.

  • identification of vascular endothelial growth factor receptor binding protein in the venom of eastern cottonmouth a new role of snake venom myotoxic lys49 phospholipase a2
    Journal of Biological Chemistry, 2005
    Co-Authors: Yasuo Yamazaki, Yukiko Matsunaga, Yuta Nakano, Takashi Morita
    Abstract:

    Abstract Vascular endothelial growth factor (VEGF165) and its receptor KDR (kinase insert domain-containing receptor) are central regulators of blood vessel formation. We herein report a KDR-binding protein we have isolated in the venom of eastern cottonmouth (Agkistrodon Piscivorus Piscivorus). Sequence analysis revealed the isolated KDR-binding protein (designated KDR-bp) is identical to Lys49-phosholipase A2 (Lys49PLA2), an inactive PLA2 homologue with strong myotoxicity, in which Lys49 substitutes Asp49, a key residue for binding the essential cofactor Ca2+. KDR-bp binds to the extracellular domain of KDR with subnanomolar affinity. KDR-bp also binds to a lesser extent with Flt-1 and IgG but not to other receptors with similar immunoglobulin-like domain structures such as platelet-derived growth factor receptor α. The interaction between KDR-bp and KDR was blocked by VEGF165, and KDR-bp specifically inhibited VEGF165-stimulated endothelial cell proliferation, indicating KDR-bp is an antagonistic ligand for KDR. Lys49PLA2s from another snake venom were found to exhibit similar receptor binding properties to KDR-bp. This is the first report to demonstrate that an exogenous factor antagonizes VEGF and its receptor system. Our observation offers further insight into the as yet unknown molecular mechanism of myotoxic activity of snake venom Lys49PLA2s. Furthermore, KDR-bp would make a valuable tool for studying the structure and function of KDR, such as that expressed on skeletal muscle cells.

  • wide distribution of cysteine rich secretory proteins in snake venoms isolation and cloning of novel snake venom cysteine rich secretory proteins
    Archives of Biochemistry and Biophysics, 2003
    Co-Authors: Yasuo Yamazaki, Fumiko Hyodo, Takashi Morita
    Abstract:

    Cysteine-rich secretory proteins (CRISPs) are found in epididymis and granules of mammals, and they are thought to function in sperm maturation and in the immune system. Recently, we isolated and obtained clones for novel snake venom proteins that are classified as CRISP family proteins. To elucidate the distribution of snake venom CRISP family proteins, we evaluated a wide range of venoms for immuno-cross-reactivity. Then we isolated, characterized, and cloned genes for three novel CRISP family proteins (piscivorin, ophanin, and catrin) from the venom of eastern cottonmouth (Agkistrodon Piscivorus Piscivorus), king cobra (Ophiophagus hannah), and western diamondback rattlesnake (Crotalus atrox). Our results show the wide distribution of snake venom CRISP family proteins among Viperidae and Elapidae from different continents, indicating that CRISP family proteins compose a new group of snake venom proteins.

  • purification and characterization of a new rgd kgd containing dimeric disintegrin piscivostatin from the venom of Agkistrodon Piscivorus Piscivorus the unique effect of piscivostatin on platelet aggregation
    Journal of Biochemistry, 2001
    Co-Authors: Daiju Okuda, Takashi Morita
    Abstract:

    Piscivostatin, a novel dimeric disintegrin containing Arg-Gly-Asp (RGD) and Lys-Gly-Asp (KGD) sequences, was isolated from the venom of Agkistrodon Piscivorus Piscivorus. The molecule consisted of two chains designated as the alpha and beta chains, comprising 65 and 68 amino acid residues, respectively. Piscivostatin had two binding motifs recognized by platelet glycoprotein IIb/IIIa (GPIIb/IIIa), and the biological activity of dimeric disintegrin piscivostatin toward platelet aggregation differed from those of other monomeric disintegrins such as trimestatin and echistatin. We measured platelet aggregation by the laser light scattering method during the process of ADP-induced platelet aggregation. Both dimeric and monomeric disintegrins inhibited the formation of small (9 to 25 microm in diameter), medium-sized and large aggregates (25 to 70 microm in diameter) in a dose-dependent manner. The platelet aggregates disaggregated after reaching a maximal number on either treatment with ADP alone or monomeric disintegrin/ADP. However, the small aggregates did not disaggregate on treatment with piscivostatin/ADP even when applied over time. When washed platelets were incubated with an anti-GPIIb/IIIa monoclonal antibody, PT25-2, which induces conformational changes of GPIIb/IIIa to a form accessible to fibrinogen and other adhesion proteins without platelet activation, piscivostatin induced a platelet shape change alone with no aggregate formation. The present study indicated that piscivostatin has two unique contradictory activities; acting as a double inhibitor of platelet aggregation and platelet aggregate dissociation.

Lomonte Bruno - One of the best experts on this subject based on the ideXlab platform.

  • Antitumor effects of cationic synthetic peptides derived from Lys49 phospholipase A2 homologues of snake venoms
    'Elsevier BV', 2007
    Co-Authors: Araya-castillo Cindy, Lomonte Bruno
    Abstract:

    The effects of two cationic synthetic peptides, derived from the C-terminal region of Lys49 phospholipase A2 homologues from snake venoms, upon various murine tumor cell lines (B16 melanoma, EMT6 mammary carcinoma, S-180 sarcoma, P3X myeloma, tEnd endothelial cells) were evaluated. The peptides are 13-mers derived from Agkistrodon Piscivorus Piscivorus Lys49 PLA2 (p-AppK: KKYKAYFKLKCKK) and Bothrops asper Lys49 myotoxin II (pEM-2[D]: KKWRWWLKALAKK), respectively, in the latter case with slight modifications and with all-D amino acids. All tumor cells tested were susceptible to the lytic action of the peptides. The susceptibility of tumor cell lines was not higher than that of C2C12 skeletal muscle myoblasts, utilized as a non-transformed cell line control. However, in a murine model of subcutaneous solid tumor growth of EMT6 mammary carcinoma, the intraperitoneal administration of pEM-2[D] caused a tumor mass reduction of 36% ( p < 0.05), which was of similar magnitude to that achieved by the administration of paclitaxel, an antitumor drug in clinical use. Thus, the C-terminal peptides of Lys49 phospholipase A2 homologues present antitumor effects that might be of interest in developing therapeutic strategies against cancer.NeTropica Sweden-Central America Research Network/[01-R-2003]/NeTropica/SueciaUniversidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

  • Identification of the myotoxic site of the Lys49 phospholipase A2 from Agkistrodon Piscivorus Piscivorus snake venom: synthetic C-terminal peptides from Lys49, but not from Asp49 myotoxins, exert membrane-damaging activities
    'Elsevier BV', 2001
    Co-Authors: Núñez, Carlos E., Angulo Ugalde Yamileth, Lomonte Bruno
    Abstract:

    Group II phospholipase A2 (PLA2) myotoxins found in the venoms of Crotalidae snakes can be divided into `Asp49' and `Lys49' isoforms, the latter being considered catalytically-inactive variants. Previous studies on one Lys49 isoform, myotoxin II from Bothrops asper, indicated that its myotoxic activity is due to the presence of a short cationic/hydrophobic sequence (115±129) near its C-terminus, which displays membrane-damaging properties. Since the C-terminal region of different group II PLA2 myotoxins presents considerable sequence variability, synthetic peptides homologous to region 115±129 of myotoxin II, but corresponding to B. asper myotoxin III (Asp49), Agkistrodon Piscivorus Piscivorus Asp49 PLA2 and Lys49 PLA2, were studied to determine the possible functional relevance of such region for the toxic activities of these proteins. Results showed that both Lys49-derived peptides (p-BaK49 and p-AppK49) were able to lyse skeletal muscle C2C12 cells in culture, and to induce edema in the mouse footpad assay. Moreover, p-AppK49, which showed a markedly stronger cytotoxic potency than p-BaK49, additionally induced skeletal muscle necrosis when injected into mice. These observations unequivocally identify the sequence 115±129 (KKYKAYFKLKCKK) of the Lys49 PLA2 of A. p. Piscivorus as containing the key structural determinants needed for myotoxicity, and represent the ®rst report of an unmodi®ed, PLA2-derived short synthetic peptide with the ability to reproduce this effect of a parent toxin in vivo. On the other hand, the two Asp49-derived peptides did not show any toxic effects in vitro or in vivo, even at high concentrations. These ®ndings suggests that Lys49 and Asp49 group II PLA2s might exert their myotoxic actions through different molecular mechanisms, by implying that the latter may not utilize their C-terminal regions as main membrane-destabilizing elements.International Foundation for Science/[F/2766-1]/IFS/SueciaConsejo Nacional para Investigaciones Científicas y Tecnológicas de Costa Rica/[98-013-FO]/CONICIT/Costa RicaUniversidad de Costa Rica/[741-99-269]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)UCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de Medicin

  • Lys-49 phospholipases A2 as active enzymes for beta-arachidonoyl phospholipid bilayer membranes
    'Informa UK Limited', 1997
    Co-Authors: Yamaguchi Yoko, Lomonte Bruno, Shimohigashi Yasuyuki, Chiwata Tsuyoshi, Tani Ayako, Chijiwa Takahisa, Ohno Motoroni
    Abstract:

    Phospholipases A2 containing Lys-49 have been reported to be extremely weak or inactive as enzyme. We have recently shown that basic proteins I and II (BP-I and BP-II), Lys- 49-PLA2s isolated from the venom of Trimeresurus flavoviridis (Habu snake), are potent to hydrolyze the arachidonate of 2-arachidonoyl-l-stearoyl-L-3-phosphatidylcholine (ASPC) in bilayer vesicles. In order to ensure such enzymatic activity of Lys-49-PLA2s, two other Lys-49- PLA2s from different snake venoms, myotoxin II (from Bothrops asper) and App-K49 (form Agkistrodon Piscivorus Piscivorus), were examined. Myotoxin II was found to be very active, even more potent than BP-II, liberating about 80% of arachidonic acid from liposomes. App-K49 was also active (about 50%) for ASPC liposomes. They were very weak or almost inactive for ASPC micelles and monomers. All these Lys-49-PLA2s were inactive for ASPC liposomes in the absence of Ca 2+. These results clearly demonstrated that Lys-49-PLA2s are the enzymes to hydrolyze the C2-ester bond of ASPC in bilayer membranes.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

  • Lys-49 phospholipases A2 as active enzymes for beta-arachidonoyl phospholipid bilayer membranes
    1997
    Co-Authors: Yamaguchi Yoko, Lomonte Bruno, Shimohigashi Yasuyuki, Chiwata Tsuyoshi, Tani Ayako, Chijiwa Takahisa, Ohno Motonori
    Abstract:

    Phospholipases A2 containing Lys-49 have been reported to be extremely weak or inactive as enzyme. We have recently shown that basic proteins I and II (BP-I and BP-II), Lys- 49-PLA2s isolated from the venom of Trimeresurus flavoviridis (Habu snake), are potent to hydrolyze the arachidonate of 2-arachidonoyl-l-stearoyl-L-3-phosphatidylcholine (ASPC) in bilayer vesicles. In order to ensure such enzymatic activity of Lys-49-PLA2s, two other Lys-49- PLA2s from different snake venoms, myotoxin II (from Bothrops asper) and App-K49 (form Agkistrodon Piscivorus Piscivorus), were examined. Myotoxin II was found to be very active, even more potent than BP-II, liberating about 80% of arachidonic acid from liposomes. App-K49 was also active (about 50%) for ASPC liposomes. They were very weak or almost inactive for ASPC micelles and monomers. All these Lys-49-PLA2s were inactive for ASPC liposomes in the absence of Ca 2+. These results clearly demonstrated that Lys-49-PLA2s are the enzymes to hydrolyze the C2-ester bond of ASPC in bilayer membranes.UCR::Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Frank S Bernardino - One of the best experts on this subject based on the ideXlab platform.

  • seasonal activity and road mortality of the snakes of the pa hay okee wetlands of everglades national park usa
    Biological Conservation, 1992
    Co-Authors: Frank S Bernardino, George H Dalrymple
    Abstract:

    Abstract The composition and activity of the snake community of the Pa-hay-okee wetlands of Everglades National Park is described. The study was conducted in February and March 1986 and from February 1987 to January 1989. A total of 1172 individuals of 16 taxa were observed, with Thamnophis sauritus, T. sirtalis, Nerodia fasciata pictiventris and Agkistrodon Piscivorus representing 89·2% of the total sample. The seasonal activity of the snakes was closely related to fluctuations in the water table. Periods of greatest snake activity coincided with the periods of greatest human visitation. Seventy-three percent of all snakes observed on the park's main road were either injured or dead. Management recommendations are provided to minimize loss.