9 results on '"Calderon, Leonardo A."'
Search Results
2. Biochemical and Biological Profile of Parotoid Secretion of the Amazonian Rhinella marina (Anura: Bufonidae).
- Author
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de Medeiros DSS, Rego TB, Dos Santos APA, Pontes AS, Moreira-Dill LS, Matos NB, Zuliani JP, Stábeli RG, Teles CBG, Soares AM, Sperotto ARM, Moura DJ, Saffi J, Caldeira CADS, Pimenta DC, and Calderon LA
- Subjects
- Animals, Bufo marinus, Anti-Bacterial Agents chemistry, Anti-Bacterial Agents metabolism, Anti-Bacterial Agents pharmacology, Bufanolides chemistry, Bufanolides metabolism, Bufanolides pharmacology, Parotid Gland metabolism, Pseudomonas aeruginosa growth & development, Skin metabolism, Staphylococcus aureus growth & development
- Abstract
Skin secretions of frogs have a high chemical complexity. They have diverse types of biomolecules, such as proteins, peptides, biogenic amines, and alkaloids. These compounds protect amphibians' skin against growth of bacteria, fungi, and protozoa and participate in defense system against attack from predators. Therewith, this work performed biochemical and biological profile of macroglands parotoid secretion from cane toad. For poison analysis, we performed molecular exclusion and reverse phase chromatography, electrophoresis, and mass spectrometry. Antimicrobial, antiplasmodial, leishmanicidal, cytotoxicity, genotoxicity, and inflammatory activity of crude and/or fractions of R. marina secretion were also evaluated. Fractionation prior to filtration from poison showed separation of low mass content (steroids and alkaloids) and high molecular mass (protein). Material below 10 kDa two steroids, marinobufagin and desacetylcinobufagin, was detected. Crude extract and fractions were active against Staphylococcus aureus , Pseudomonas aeruginosa , Escherichia coli , Plasmodium falciparum , Leishmania guyanensis , and Leishmania braziliensis . Crude extract was also active against cancer cells although it was not cytotoxic for normal cells. This extract did not show significant DNA damage but it showed an important inflammatory effect in vivo. The information obtained in this work contributes to the understanding of the constituents of R . marina secretion as well as the bioactive potential of these molecules.
- Published
- 2019
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3. Purification and biochemical characterization of three myotoxins from Bothrops mattogrossensis snake venom with toxicity against Leishmania and tumor cells.
- Author
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de Moura AA, Kayano AM, Oliveira GA, Setúbal SS, Ribeiro JG, Barros NB, Nicolete R, Moura LA, Fuly AL, Nomizo A, da Silva SL, Fernandes CF, Zuliani JP, Stábeli RG, Soares AM, and Calderon LA
- Subjects
- Animals, Cell Line, Tumor, Cell Survival drug effects, Male, Mice, Mycotoxins isolation & purification, Neoplasms, Experimental pathology, Snake Venoms isolation & purification, Survival Rate, Treatment Outcome, Bothrops metabolism, Leishmania drug effects, Mycotoxins chemistry, Mycotoxins pharmacology, Neoplasms, Experimental drug therapy, Snake Venoms chemistry, Snake Venoms pharmacology
- Abstract
Bothrops mattogrossensis snake is widely distributed throughout eastern South America and is responsible for snakebites in this region. This paper reports the purification and biochemical characterization of three new phospholipases A2 (PLA2s), one of which is presumably an enzymatically active Asp49 and two are very likely enzymatically inactive Lys49 PLA2 homologues. The purification was obtained after two chromatographic steps on ion exchange and reverse phase column. The 2D SDS-PAGE analysis revealed that the proteins have pI values around 10, are each made of a single chain, and have molecular masses near 13 kDa, which was confirmed by MALDI-TOF mass spectrometry. The N-terminal similarity analysis of the sequences showed that the proteins are highly homologous with other Lys49 and Asp49 PLA2s from Bothrops species. The PLA2s isolated were named BmatTX-I (Lys49 PLA2-like), BmatTX-II (Lys49 PLA2-like), and BmatTX-III (Asp49 PLA2). The PLA2s induced cytokine release from mouse neutrophils and showed cytotoxicity towards JURKAT (leukemia T) and SK-BR-3 (breast adenocarcinoma) cell lines and promastigote forms of Leishmania amazonensis. The structural and functional elucidation of snake venoms components may contribute to a better understanding of the mechanism of action of these proteins during envenomation and their potential pharmacological and therapeutic applications.
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- 2014
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4. Isolation and biochemical characterization of a new thrombin-like serine protease from Bothrops pirajai snake venom.
- Author
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Zaqueo KD, Kayano AM, Simões-Silva R, Moreira-Dill LS, Fernandes CF, Fuly AL, Maltarollo VG, Honório KM, da Silva SL, Acosta G, Caballol MA, de Oliveira E, Albericio F, Calderon LA, Soares AM, and Stábeli RG
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- Animals, Bothrops, Humans, Molecular Weight, Phenylmethylsulfonyl Fluoride chemistry, Serine Proteinase Inhibitors chemistry, Crotalid Venoms, Factor VIII chemistry, Fibrinolysis, Serine Proteases chemistry, Serine Proteases isolation & purification
- Abstract
This paper presents a novel serine protease (SP) isolated from Bothrops pirajai, a venomous snake found solely in Brazil that belongs to the Viperidae family. The identified SP, named BpirSP-39, was isolated by three chromatographic steps (size exclusion, bioaffinity, and reverse phase chromatographies). The molecular mass of BpirSP-39 was estimated by SDS-PAGE and confirmed by mass spectrometry (39,408.32 Da). The protein was able to form fibrin networks, which was not observed in the presence of serine protease inhibitors, such as phenylmethylsulfonyl fluoride (PMSF). Furthermore, BpirSP-39 presented considerable thermal stability and was apparently able to activate factor XIII of the blood coagulation cascade, unlike most serine proteases. BpirSP-39 was capable of hydrolyzing different chromogenic substrates tested (S-2222, S-2302, and S-2238) while Cu(2+) significantly diminished BspirSP-39 activity on the three tested substrates. The enzyme promoted platelet aggregation and also exhibited fibrinogenolytic, fibrinolytic, gelatinolytic, and amidolytic activities. The multiple alignment showed high sequence similarity to other thrombin-like enzymes from snake venoms. These results allow us to conclude that a new SP was isolated from Bothrops pirajai snake venom.
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- 2014
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5. Snake venom L-amino acid oxidases: trends in pharmacology and biochemistry.
- Author
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Izidoro LF, Sobrinho JC, Mendes MM, Costa TR, Grabner AN, Rodrigues VM, da Silva SL, Zanchi FB, Zuliani JP, Fernandes CF, Calderon LA, Stábeli RG, and Soares AM
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- Humans, Structure-Activity Relationship, Biological Factors chemistry, Biological Factors pharmacology, L-Amino Acid Oxidase chemistry, L-Amino Acid Oxidase pharmacology, Snake Venoms chemistry, Snake Venoms pharmacology
- Abstract
L-amino acid oxidases are enzymes found in several organisms, including venoms of snakes, where they contribute to the toxicity of ophidian envenomation. Their toxicity is primarily due to enzymatic activity, but other mechanisms have been proposed recently which require further investigation. L-amino acid oxidases exert biological and pharmacological effects, including actions on platelet aggregation and the induction of apoptosis, hemorrhage, and cytotoxicity. These proteins present a high biotechnological potential for the development of antimicrobial, antitumor, and antiprotozoan agents. This review provides an overview of the biochemical properties and pharmacological effects of snake venom L-amino acid oxidases, their structure/activity relationship, and supposed mechanisms of action described so far.
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- 2014
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6. Biochemical and functional characterization of Parawixia bistriata spider venom with potential proteolytic and larvicidal activities.
- Author
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Gimenez GS, Coutinho-Neto A, Kayano AM, Simões-Silva R, Trindade F, de Almeida e Silva A, Marcussi S, da Silva SL, Fernandes CF, Zuliani JP, Calderon LA, Soares AM, and Stábeli RG
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- Aedes drug effects, Animals, Anticoagulants pharmacology, Bacteria drug effects, Cell Nucleus drug effects, Cell Nucleus metabolism, Chromatography, Ion Exchange, Electrophoresis, Gel, Two-Dimensional, Fibrinogen metabolism, Fungi drug effects, Humans, Larva drug effects, Lymphocytes drug effects, Lymphocytes metabolism, Male, Mice, Microbial Sensitivity Tests, Insecticides toxicity, Proteolysis drug effects, Spider Venoms toxicity, Spiders chemistry
- Abstract
Toxins purified from the venom of spiders have high potential to be studied pharmacologically and biochemically. These biomolecules may have biotechnological and therapeutic applications. This study aimed to evaluate the protein content of Parawixia bistriata venom and functionally characterize its proteins that have potential for biotechnological applications. The crude venom showed no phospholipase, hemorrhagic, or anti-Leishmania activities attesting to low genotoxicity and discrete antifungal activity for C. albicans. However the following activities were observed: anticoagulation, edema, myotoxicity and proteolysis on casein, azo-collagen, and fibrinogen. The chromatographic and electrophoretic profiles of the proteins revealed a predominance of acidic, neutral, and polar proteins, highlighting the presence of proteins with high molecular masses. Five fractions were collected using cation exchange chromatography, with the P4 fraction standing out as that of the highest purity. All fractions showed proteolytic activity. The crude venom and fractions P1, P2, and P3 showed larvicidal effects on A. aegypti. Fraction P4 showed the presence of a possible metalloprotease (60 kDa) that has high proteolytic activity on azo-collagen and was inhibited by EDTA. The results presented in this study demonstrate the presence of proteins in the venom of P. bistriata with potential for biotechnological applications.
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- 2014
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7. Antitumoral activity of snake venom proteins: new trends in cancer therapy.
- Author
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Calderon LA, Sobrinho JC, Zaqueo KD, de Moura AA, Grabner AN, Mazzi MV, Marcussi S, Nomizo A, Fernandes CF, Zuliani JP, Carvalho BM, da Silva SL, Stábeli RG, and Soares AM
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- Animals, Humans, Molecular Targeted Therapy, Antineoplastic Agents therapeutic use, Neoplasms drug therapy, Snake Venoms therapeutic use
- Abstract
For more than half a century, cytotoxic agents have been investigated as a possible treatment for cancer. Research on animal venoms has revealed their high toxicity on tissues and cell cultures, both normal and tumoral. Snake venoms show the highest cytotoxic potential, since ophidian accidents cause a large amount of tissue damage, suggesting a promising utilization of these venoms or their components as antitumoral agents. Over the last few years, we have studied the effects of snake venoms and their isolated enzymes on tumor cell cultures. Some in vivo assays showed antineoplastic activity against induced tumors in mice. In human beings, both the crude venom and isolated enzymes revealed antitumor activities in preliminary assays, with measurable clinical responses in the advanced treatment phase. These enzymes include metalloproteases (MP), disintegrins, L-amino acid oxidases (LAAOs), C-type lectins, and phospholipases A2 (PLA2s). Their mechanisms of action include direct toxic action (PLA2s), free radical generation (LAAOs), apoptosis induction (PLA2s, MP, and LAAOs), and antiangiogenesis (disintegrins and lectins). Higher cytotoxic and cytostatic activities upon tumor cells than normal cells suggest the possibility for clinical applications. Further studies should be conducted to ensure the efficacy and safety of different snake venom compounds for cancer drug development.
- Published
- 2014
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8. Activation of J77A.1 macrophages by three phospholipases A2 isolated from Bothrops atrox snake venom.
- Author
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Furtado JL, Oliveira GA, Pontes AS, Setúbal Sda S, Xavier CV, Lacouth-Silva F, Lima BF, Zaqueo KD, Kayano AM, Calderon LA, Stábeli RG, Soares AM, and Zuliani JP
- Subjects
- Animals, Bothrops, Macrophages enzymology, Phagocytosis drug effects, Phospholipases A2 administration & dosage, Phospholipases A2 chemistry, Tumor Necrosis Factor-alpha metabolism, Macrophages drug effects, Phospholipases A2 metabolism, Snake Venoms enzymology
- Abstract
In the present study, we investigated the in vitro effects of two basic myotoxic phospholipases A2 (PLA2), BaTX-I, a catalytically inactive Lys-49 variant, and BaTX-II, a catalytically active Asp-49, and of one acidic myotoxic PLA2, BaPLA2, a catalytically active Asp-49, isolated from Bothrops atrox snake venom, on the activation of J774A.1 macrophages. At noncytotoxic concentrations, the toxins did not affect the adhesion of the macrophages, nor their ability to detach. The data obtained showed that only BaTX-I stimulated complement receptor-mediated phagocytosis. However, BaTX-I, BaTX-II, and BaPLA2 induced the release of the superoxide anion by J774A.1 macrophages. Additionally, only BaTX-I raised the lysosomal volume of macrophages after 15 min of incubation. After 30 min, all the phospholipases increased this parameter, which was not observed within 60 min. Moreover, BaTX-I, BaTX-II, and BaPLA2 increased the number of lipid bodies on macrophages submitted to phagocytosis and not submitted to phagocytosis. However, BaTX-II and BaPLA2 induced the release of TNF-α by J774A.1 macrophages. Taken together, the data show that, despite differences in enzymatic activity, the three toxins induced inflammatory events and whether the enzyme is acidic or basic does not seem to contribute to these effects.
- Published
- 2014
- Full Text
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9. Purification and characterization of BmooAi: a new toxin from Bothrops moojeni snake venom that inhibits platelet aggregation.
- Author
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de Queiroz MR, Mamede CC, de Morais NC, Fonseca KC, de Sousa BB, Migliorini TM, Pereira DF, Stanziola L, Calderon LA, Simões-Silva R, Soares AM, and de Oliveira F
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- Amino Acid Sequence, Animals, Cattle, Chromatography, Ion Exchange, Collagen pharmacology, Crotalid Venoms chemistry, Epinephrine pharmacology, Humans, Molecular Sequence Data, Molecular Weight, Platelet Aggregation Inhibitors chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Bothrops metabolism, Crotalid Venoms isolation & purification, Crotalid Venoms pharmacology, Platelet Aggregation drug effects, Platelet Aggregation Inhibitors pharmacology
- Abstract
In this paper, we describe the purification/characterization of BmooAi, a new toxin from Bothrops moojeni that inhibits platelet aggregation. The purification of BmooAi was carried out through three chromatographic steps (ion-exchange on a DEAE-Sephacel column, molecular exclusion on a Sephadex G-75 column, and reverse-phase HPLC chromatography on a C2/C18 column). BmooAi was homogeneous by SDS-PAGE and shown to be a single-chain protein of 15,000 Da. BmooAi was analysed by MALDI-TOF Spectrometry and revealed two major components with molecular masses 7824.4 and 7409.2 as well as a trace of protein with a molecular mass of 15,237.4 Da. Sequencing of BmooAi by Edman degradation showed two amino acid sequences: IRDFDPLTNAPENTA and ETEEGAEEGTQ, which revealed no homology to any known toxin from snake venom. BmooAi showed a rather specific inhibitory effect on platelet aggregation induced by collagen, adenosine diphosphate, or epinephrine in human platelet-rich plasma in a dose-dependent manner, whereas it had little or no effect on platelet aggregation induced by ristocetin. The effect on platelet aggregation induced by BmooAi remained active even when heated to 100°C. BmooAi could be of medical interest as a new tool for the development of novel therapeutic agents for the prevention and treatment of thrombotic disorders.
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- 2014
- Full Text
- View/download PDF
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