Search

The worrisome emergence of pathogens resistant to conventional drugs has stimulated the search for new classes of antimicrobial and antiparasitic agents from natural sources. Antimicrobial peptides (AMPs), acting through mechanisms that do not rely on the interaction with a specific receptor, provide new possibilities for the development of drugs against resistant organisms. This study sought to purify and proteomically characterize the antimicrobial and antiparasitic peptidomes of B. atrox and B. jararacussu snake venoms against Gram-positive (Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus—MRSA), Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria, and the protozoan parasites Leishmania amazonensis and Plasmodium falciparum (clone W2, resistant to chloroquine). To this end, B. atrox and B. jararacussu venom peptides were purified by combination of 3 kDa cut-off Amicon® ultracentrifugal filters and reverse-phase high-performance liquid chromatography, and then identified by electrospray-ionization Ion-Trap/Time-of-Flight mass spectrometry. Fourteen distinct peptides, with masses ranging from 443.17 to 1383.73 Da and primary structure between 3 and 13 amino acid residues, were sequenced. Among them, 13 contained unique sequences, including 4 novel bradykinin-potentiating-like peptides (BPPs), and a snake venom metalloproteinase tripeptide inhibitor (SVMPi). Although commonly found in Viperidae venoms, except for Bax-12, the BPPs and SVMPi here reported had not been described in B. atrox and B. jararacussu venoms. Among the novel peptides, some exhibited bactericidal activity towards P. aeruginosa and S. aureus, had low hemolytic effect, and were devoid of antiparasitic activity. The identified novel antimicrobial peptides may be relevant in the development of new drugs for the management of multidrug-resistant Gram-negative and Gram-positive bacteria.

We report a structural and functional proteomics characterization of the venoms of the two subspecies (bilineatus and smaragdinus) of the South American palm pitviper B. bilineatus from the Brazili...

Background:Functional and structural diversity of proteins of snake venoms is coupled with a wide repertoire of pharmacological effects. Snake venoms are targets of studies linked to searching molecules with biotechnological potential.Methods:A homologue phospholipase A2 (BmatTX-IV) was obtained using two chromatographic techniques. Mass spectrometry and two-dimensional gel electrophoresis were used to determine the molecular mass and isoelectric point, respectively. By means of Edman degradation chemistry, it was possible to obtain the partial sequence of amino acids that comprise the isolated toxin. Trypanocidal, leishmanicidal and cytoxic activity against Trypanosoma cruzi, Leishmania infantum and murine fibrobasts was determinated.Results:Combination of both chromatographic steps used in this study demonstrated efficacy to obtain the PLA2-Lys49. BmatTX-IV showed molecular mass and isoelectric point of 13.55 kDa and 9.3, respectively. Amino acid sequence of N-terminal region (51 residues) shows the presence of Lys49 residue at position 49, a distinctive trait of enzymatically inactive PLA2. Bothrops mattogrossensis snake venom showed IC50 values of 11.9 μg/mL against Leishmania infantum promastigotes and of 13.8 μg/mL against Trypanosoma cruzi epimastigotes, respectively. On the other hand, the venom showed a high cytotoxic activity (IC50 value of 16.7 μg/mL) against murine fibroblasts, whereas the BmatTX-IV showed IC50 value of 81.2 μg/mL.Conclusion:Physicochemical and biological characterization of snake venoms components is critically important, since these complex mixtures provide a source of molecules with antiparasitic potential, making further studies necessary to identify and characterize components with higher efficacy and selectivity.

A comparative venom proteomic analysis of the Brazilian southern coral snake, M. frontalis, the Amazon coral snake M. spixii spixii, and the aquatic coral snake M. surinamensis is reported. Venoms from M. frontalis and M. s. spixii were composed mainly (>90% of the total venom proteome) by 3FTxs and PLAs in different proportions, and minor proteins from 2 to 5 protein families. Conversely, the aquatic coral snake expressed a streamlined (95%) 3FTx venom with low abundance (4.2%) of PLA molecules. A compositional-lethal activity for natural prey correlation analysis suggests that M. surinamensis venom may has evolved under strong pressure to quickly immobilize aquatic prey. On the other hand, venoms from M. frontalis and M. s. spixii, whose diet consist mainly of amphisbaenians and colubrid snakes, may have been shaped through balancing selection. Our work provides strong evidence for the occurrence in M. frontalis venom, but not in those from M. s. spixi and M. surinamensis, of a KUN-PLA complex homologue to heterodimeric venom toxins from some long-tailed monadal coral snakes that target acid-sensing receptors ASIC1a/2 evoking pain. The M. frontalis protein would represent the first example of a KUN-PLA heterodimer in a South American short-tailed triadal coral snake venom., This study was partly supported by grant BFU 2017-89103-P from the Ministerio de Ciencia, Innovación y Universidades, Madrid (Spain)to JJC. The authors wish to gratefully acknowledge the collaboration ofDr. Kayena Delaix Zaqueo inM. surinamensisvenom extraction. Authorsalso express their gratitude to Conselho Nacional de DesenvolvimentoCientífico e Tecnológico (CNPq/MCTIC), Coordenação deAperfeiçoamento de Pessoal de Nível Superior (CAPES/MEC) andFundação Rondônia de Amparo ao Desenvolvimento das AçõesCientíficas e Tecnológicas de Pesquisa do Estado de Rondônia(FAPERO) forfinancial support. The authors thank the Program forTechnological Development in Tools for Health-PDTIS-FIOCRUZ for theuse of its facilities.

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 ofR. marinasecretion 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 againstStaphylococcus aureus,Pseudomonas aeruginosa,Escherichia coli,Plasmodium falciparum,Leishmania guyanensis, andLeishmania 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 ofR.marinasecretion as well as the bioactive potential of these molecules.

Snake venom phospholipases A2 (PLA2 s) are responsible for numerous pathophysiological effects in snakebites; however, their biochemical properties favour antimicrobial actions against different pathogens, thus constituting a true source of potential microbicidal agents. This study describes the isolation of a Lys49 PLA2 homologue from Lachesis muta muta venom using two chromatographic steps: size exclusion and reverse phase. The protein showed a molecular mass of 13,889 Da and was devoid of phospholipase activity on an artificial substrate. The primary structure made it possible to identify an unpublished protein from L. m. muta venom, named LmutTX, that presented high identity with other Lys49 PLA2 s from bothropic venoms. Synthetic peptides designed from LmutTX were evaluated for their cytotoxic and antimicrobial activities. LmutTX was cytotoxic against C2C12 myotubes at concentrations of at least 200 μg/mL, whereas the peptides showed a low cytolytic effect. LmutTX showed antibacterial activity against Gram-positive and Gram-negative bacteria; however, S. aureusATCC 29213 and MRSA strains were more sensitive to the toxin's action. Synthetic peptides were tested on S. aureus, MRSA and P. aeruginosaATCC 27853 strains, showing promising results. This study describes for the first time the isolation of a Lys49 PLA2 from Lachesis snake venom and shows that peptides from specific regions of the sequence may constitute new sources of molecules with biotechnological potential.

Made available in DSpace on 2018-12-11T16:47:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-10-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Phospholipases A2 inhibitors (PLIs) produced by venomous and non-venomous snakes play essential role in this resistance. These endogenous inhibitors may be classified by their fold in PLIα, PLIβ and PLIγ. Phospholipases A2 (PLA2s) develop myonecrosis in snake envenomation, a consequence that is not efficiently neutralized by antivenom treatment. This work aimed to identify and characterize two PLIs from Amazonian snake species, Bothrops atrox and Micrurus lemniscatus. Liver tissues RNA of specimens from each species were isolated and amplified by RT-PCR using PCR primers based on known PLIγ gene sequences, followed by cloning and sequencing of amplified fragments. Sequence similarity studies showed elevated identity with inhibitor PLIγ gene sequences from other snake species. Molecular models of translated inhibitors' gene sequences resemble canonical three finger fold from PLIγ and support the hypothesis that the decapeptide (residues 107–116) may be responsible for PLA2 inhibition. Structural studies and action mechanism of these PLIs may provide necessary information to evaluate their potential as antivenom or as complement of the current ophidian accident treatment. Centro de Estudos de Biomoléculas Aplicadas a Saúde CEBio Fundação Oswaldo Cruz FIOCRUZ Fiocruz Rondônia and Departamento de Medicina Universidade Federal de Rondônia UNIR Departamento de Física e Biofísica Instituto de Biociências Universidade Estadual Paulista UNESP Center for the Study of Biological Complexity Life Sciences Virginia Commonwealth University PVE-CNPq Centro Universitário São Lucas UNISL Departamento de Física e Biofísica Instituto de Biociências Universidade Estadual Paulista UNESP

Made available in DSpace on 2018-12-11T16:47:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-09-01 Snake venoms contain various proteins, especially phospholipases A2 (PLA2s), which present potential applications in diverse areas of health and medicine. In this study, a new basic PLA2 from Bothrops marajoensis with parasiticidal activity was purified and characterized biochemically and biologically. B. marajoensis venom was fractionated through cation exchange followed by reverse phase chromatographies. The isolated toxin, BmajPLA2-II, was structurally characterized with MALDI-TOF (Matrix-assisted laser desorption/ionization-time of flight) mass spectrometry, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), followed by two-dimensional electrophoresis, partial amino acid sequencing, an enzymatic activity assay, circular dichroism, and dynamic light scattering assays. These structural characterization tests presented BmajPLA2-II as a basic Lys49 PLA2 homologue, compatible with other basic snake venom PLA2s (svPLA2), with a tendency to form aggregations. The in vitro anti-parasitic potential of B. marajoensis venom and of BmajPLA2-II was evaluated against Leishmania infantum promastigotes and Trypanosoma cruzi epimastigotes, showing significant activity at a concentration of 100 μg/mL. The venom and BmajPLA2-II presented IC50 of 0.14 ± 0.08 and 6.41 ± 0.64 μg/mL, respectively, against intraerythrocytic forms of Plasmodium falciparum with CC50 cytotoxicity values against HepG2 cells of 43.64 ± 7.94 and >150 μg/mL, respectively. The biotechnological potential of these substances in relation to leishmaniasis, Chagas disease and malaria should be more deeply investigated. Centro de Estudos de Biomoléculas Aplicadas à Saúde CEBio Fundação Oswaldo Cruz FIOCRUZ Fiocruz Rondônia Departamento de Medicina Universidade Federal de Rondônia UNIR Centro para el Desarrollo de la Investigación Científica CEDIC Laboratório da Plataforma de Bioensaios de Malária e Leishmaniose Fiocruz Rondônia Faculdade São Lucas FSL Departamento de Física e Biofísica Universidade Estadual Paulista UNESP Laboratório de Bioquímica e Biofísica Instituto Butantan Departamento de Física e Biofísica Universidade Estadual Paulista UNESP

Phospholipases A 2 (PLA 2 s) constitute a class of extensively studied toxins, isolated from snake venoms. Basic PLA 2 isoforms mediate various toxicological effects, while the acidic isoforms generally have higher enzymatic activities, but do not promote evident toxic effects. The functions of these acidic isoforms in snake venoms are still not completely understood and more studies are needed to characterize the biological functions and diversification of acidic toxins in order to justify their abundant presence in these secretions. Recently, Lomonte and collaborators demonstrated, in a proteomic and toxicological study, high concentrations of PLA 2 s in the venom of Agkistrodon piscivorus leucostoma. We have, herein, purified and characterized an acidic PLA 2 from this snake venom, denominated AplTx-I, in order to better understand its biochemical and structural characteristics, as well as its biological effects. AplTx-I was purified using two chromatographic steps, in association with enzymatic and biological assays. The acidic toxin was found to be one of the most abundant proteins in the venom of A. p. leucostoma; the protein was monomeric with a molecular mass of 13,885.8 Da, as identified by mass spectrometry ESI-TOF and electrophoresis. The toxin has similar primary and tridimensional structures to those of other acidic PLA 2 s, a theoretical and experimental isoelectric point of ≈5.12, and a calcium-dependent enzyme activity of 25.8985 nM/min/mg, with maximum values at 37 °C and pH 8.0. Despite its high enzymatic activity on synthetic substrate, AplTx-I did not induce high or significant myotoxic, coagulant, anticoagulant, edema, neuromuscular toxicity in mouse phrenic nerve-diaphragm preparations or antibacterial activities. Interestingly, AplTx-I triggered a high and selective neuromuscular toxicity in chick biventer cervicis preparations. These findings are relevant to provide a deeper understanding of the pharmacology, role and diversification of acidic phospholipase A 2 isoforms in snake venoms.

14 páginas, 3 figuras, 2 tablas. The datasets generated during the current study are available in Additional file 1 (Table S1) and Additional file 2 (Table S2). Raw mass spectrometric data are available from the corresponding authors on reasonable request., BACKGROUND: The Brazil's lancehead, Bothrops brazili, is a poorly studied pit viper distributed in lowlands of the equatorial rainforests of southern Colombia, northeastern Peru, eastern Ecuador, southern and southeastern Venezuela, Guyana, Suriname, French Guiana, Brazil, and northern Bolivia. Few studies have been reported on toxins isolated from venom of Ecuadorian and Brazilian B. brazili. The aim of the present study was to elucidate the qualitative and quantitative protein composition of B. brazili venom from Pará (Brazil), and to carry out a comparative antivenomics assessment of the immunoreactivity of the Brazilian antibothropic pentavalent antivenom [soro antibotrópico (SAB) in Portuguese] against the venoms of B. brazili and reference species, B. jararaca. METHODS: We have applied a quantitative snake venomics approach, including reverse-phase and two-dimensional electrophoretic decomplexation of the venom toxin arsenal, LC-ESI-MS mass profiling and peptide-centric MS/MS proteomic analysis, to unveil the overall protein composition of B. brazili venom from Pará (Brazil). Using third-generation antivenomics, the specific and paraspecific immunoreactivity of the Brazilian SAB against homologous (B. jararaca) and heterologous (B. brazili) venoms was investigated. RESULTS: The venom proteome of the Brazil's lancehead (Pará) is predominantly composed of two major and three minor acidic (19%) and two major and five minor basic (14%) phospholipase A2 molecules; 7-11 snake venom metalloproteinases of classes PI (21%) and PIII (6%); 10-12 serine proteinases (14%), and 1-2 L-amino acid oxidases (6%). Other toxins, including two cysteine-rich secretory proteins, one C-type lectin-like molecule, one nerve growth factor, one 5'-nucleotidase, one phosphodiesterase, one phospholipase B, and one glutaminyl cyclase molecule, represent together less than 2.7% of the venom proteome. Third generation antivenomics profile of the Brazilian pentabothropic antivenom showed paraspecific immunoreactivity against all the toxin classes of B. brazili venom, with maximal binding capacity of 132.2 mg venom/g antivenom. This figure indicates that 19% of antivenom's F(ab')2 antibodies bind B. brazili venom toxins. CONCLUSION: The proteomics outcome contribute to a deeper insight into the spectrum of toxins present in the venom of the Brazil's lancehead, and rationalize the pathophysiology underlying this snake bite envenomings. The comparative qualitative and quantitative immunorecognition profile of the Brazilian pentabothropic antivenom toward the venom toxins of B. brazili and B. jararaca (the reference venom for assessing the bothropic antivenom's potency in Brazil), provides clues about the proper use of the Brazilian antibothropic polyvalent antivenom in the treatment of bites by the Brazil's lancehead., This study was partly supported by grant BFU2017-89103-P from the Ministerio de Ciencia, Innovación y Universidades, Madrid (Spain) to JJC. The authors wish to express their gratitude to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/MCTIC), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/MEC) and Fundação Rondônia de Amparo ao Desenvolvimento das Ações Científicas e Tecnológicas de Pesquisa do Estado de Rondônia (FAPERO) for financial support.

Malaria is a parasitic infectious disease and was responsible for 400.000 deaths in 2018. Plasmodium falciparum represents the species that causes most human deaths due to severe malaria. In addition, studies prove the resistance of P. falciparum to drugs used to treat malaria, making the search for new drugs with antiplasmodial potential necessary. In this context, the literature describes snake venoms as a rich source of molecules with microbicidal potential, including phospholipases A2 (PLA2s). In this sense, the present study aimed to isolate basic PLA2s from Paraguayan Bothrops diporus venom and evaluate their antiplasmodial potential. Basic PLA2s were obtained using two chromatographic steps. Initially, B. diporus venom was subjected to ion exchange chromatography (IEC). The electrophoretic profile of the fractions from the IEC permitted the selection of 3 basic fractions, which were subjected to reverse phase chromatography, resulting in the isolation of the PLA2s. The toxins were tested for enzymatic activity using a chromogenic substrate and finally, the antiplasmodial, cytotoxic potential and hemolytic activity of the isolated toxins were evaluated. The electrophoretic profile of the fractions from the IEC permitted the selection of 3 basic fractions, which were subjected to reverse phase chromatography, resulting in the isolation of the two enzymatically active PLA2s, BdTX-I and BdTX-II and the PLA2 homologue BdTX-III. The antiplasmodial potential was evaluated and the toxins showed IC50 values of: 2.44, 0.0153 and 0.59 μg/mL respectively, presenting PLA2 selectivity according to the selectivity index results (SI) calculated against HepG2 cells. The results show that the 3 basic phospholipases isolated in this study have a potent antiparasitic effect against the W2 strain of P. falciparum. In view of the results obtained in this work, further research are necessary to determine the mechanism of action by which these toxins cause cell death in parasites.

INTRODUCTION Leishmaniasis, Chagas disease, and malaria cause morbidity globally. The drugs currently used for treatment have limitations. Activity of cinnamic acid analogs against Leishmania spp., Trypanosoma cruzi, and Plasmodium falciparum was evaluated in the interest of identifying new antiprotozoal compounds. METHODS In vitro effects of analogs against L. braziliensis, L. infantum chagasi, T. cruzi, and P. falciparum, and hemolytic and cytotoxic activities on NCTC 929 were determined. RESULTS Three analogs showed leishmanicidal and tripanocidal activity. No antiplasmodial, hemolytic, or cytotoxic activity was observed. CONCLUSIONS Antiprotozoal activity of analogs against L. infantum braziliensis, L. infantum chagasi, and T. cruzi was demonstrated.

Metalloproteases play a fundamental role in snake venom envenomation inducing hemorrhagic, fibrigen(ogen)olytic and myotoxic effects in their victims. Several snake venoms, such as those from the Bothrops genus, present important local effects which are not efficiently neutralized by conventional serum therapy. Consequently, these accidents may result in permanent sequelae and disability, creating economic and social problems, especially in developing countries, leading the attention of the World Health Organization that considered ophidic envenomations a neglected tropical disease. Aiming to produce an efficient inhibitor against bothropic venoms, we synthesized different molecules classified as quinolinones – a group of low-toxic chemical compounds widely used as antibacterial and antimycobacterial drugs – and tested their inhibitory properties against hemorrhage caused by bothropic venoms. The results from this initial screening indicated the molecule 2-hydroxymethyl-6-methoxy-1,4-dihydro-4-quinolinone (Q8) was the most effective antihemorrhagic compound among all of the assayed synthetic quinolinones. Other in vitro and in vivo experiments showed this novel compound was able to inhibit significantly the hemorrhagic and/or proteolytic activities of bothropic crude venoms and isolated snake venom metalloproteases (SVMPs) even at lower concentrations. Docking and molecular dynamic simulations were also performed to get insights into the structural basis of Q8 inhibitory mechanism against proteolytic and hemorrhagic SVMPs. These structural studies demonstrated that Q8 may form a stable complex with SVMPs, impairing the access of substrates to the active sites of these toxins. Therefore, both experimental and structural data indicate that Q8 compound is an interesting candidate for antiophidic therapy, particularly for the treatment of the hemorrhagic and necrotic effects induced by bothropic venoms.

The Micrurus genus is the American representative of Elapidae family. Micrurus spixii is endemic of South America and northern states of Brazil. Elapidic venoms contain neurotoxins that promote curare-mimetic neuromuscular blockage. In this study, biochemical and functional characterizations of M. spixii crude venom were performed and a new neurotoxic phospholipase A2 called MsPLA2-I was isolated. M. spixii crude venom caused severe swelling in the legs of tested mice and significant release of creatine kinase (CK) showing its myotoxic activity. Leishmanicidal activity against Leishmania amazonensis (IC50 1.24 μg/mL) was also observed, along with antiplasmodial activity against Plasmodium falciparum, which are unprecedented for Micrurus venoms. MsPLA2-I with a Mr 12,809.4 Da was isolated from the crude venom of M. spixii. The N-terminal sequencing of a fragment of 60 amino acids showed 80% similarity with another PLA2 from Micrurus altirostris. This toxin and the crude venom showed phospholipase activity. In a mouse phrenic nerve-diaphragm preparation, M. spixii venom and MsPLA2-I induced the blockage of both direct and indirect twitches. While the venom presented a pronounced myotoxic activity, MsPLA2-I expressed a summation of neurotoxic activity. The results of this study make M. spixii crude venom promising compounds in the exploration of molecules with microbicidal potential.

Made available in DSpace on 2018-12-11T17:38:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-08-28. Added 1 bitstream(s) on 2019-10-09T18:33:19Z : No. of bitstreams: 1 S1678-91992018000100313.pdf: 5810239 bytes, checksum: 1f7caf8f8612205ab464347b78c03c91 (MD5) Background: Cnidarians produce toxins, which are composed of different polypeptides that induce pharmacological effects of biotechnological interest, such as antitumor, antiophidic and anti-clotting activities. This study aimed to evaluate toxicological activities and potential as antitumor and antiophidic agents contained in total extracts from five cnidarians: Millepora alcicornis, Stichodactyla helianthus, Plexaura homomalla, Bartholomea annulata and Condylactis gigantea (total and body wall). Methods: The cnidarian extracts were evaluated by electrophoresis and for their phospholipase, proteolytic, hemorrhagic, coagulant, fibrinogenolytic, neuromuscular blocking, muscle-damaging, edema-inducing and cytotoxic activities. Results: All cnidarian extracts showed indirect hemolytic activity, but only S. helianthus induced direct hemolysis and neurotoxic effect. However, the hydrolysis of NBD-PC, a PLA2 substrate, was presented only by the C. gigantea (body wall) and S. helianthus. The extracts from P. homomalla and S. helianthus induced edema, while only C. gigantea and S. helianthus showed intensified myotoxic activity. The proteolytic activity upon casein and fibrinogen was presented mainly by B. annulata extract and all were unable to induce hemorrhage or fibrinogen coagulation. Cnidarian extracts were able to neutralize clotting induced by Bothrops jararacussu snake venom, except M. alcicornis. All cnidarian extracts were able to inhibit hemorrhagic activity induced by Bothrops moojeni venom. Only the C. gigantea (body wall) inhibited thrombin-induced coagulation. All cnidarian extracts showed antitumor effect against Jurkat cells, of which C. gigantea (body wall) and S. helianthus were the most active; however, only C. gigantea (body wall) and M. alcicornis were active against B16F10 cells. Conclusion: The cnidarian extracts analyzed showed relevant in vitro inhibitory potential over the activities induced by Bothrops venoms; these results may contribute to elucidate the possible mechanisms of interaction between cnidarian extracts and snake venoms. Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio) Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia) Brazilian Marine Biotechnology Network (BioTecMar Network) Universidade Federal de Rondônia (UNIR) Departamento de Medicina Universidad de La Habana Centro de Estudios de Proteínas Facultad de Biología Universidade Federal de Lavras (UFLA) Departamento de Química Universidade Federal Fluminense (UFF) Departamento de Biologia Celular e Molecular (GCM) Instituto de Biologia Universidade Estadual Paulista (UNESP) Departamento de Farmacologia Instituto de Biociências Universidade Federal de Minas Gerais (UFMG) Instituto de Ciências Biológicas Departamento de Farmacologia Universidade Estadual Paulista (UNESP) Departamento de Morfologia Instituto de Biociências Centro Universitário São Lucas (UniSL) Universidade Estadual Paulista (UNESP) Departamento de Farmacologia Instituto de Biociências Universidade Estadual Paulista (UNESP) Departamento de Morfologia Instituto de Biociências

Leguminous seeds (Fabaceae) have a high content of inhibitors of which serine protease inhibitors are the most widely studied. However, there are only a few studies related to the investigation of these proteins in tree species belonging to the Amazon flora. The protein content presented in seeds of four Amazonian Leguminosae species, Parkia pendula, P. discolor, P. multijuga and P. Nitida, was extracted by using NaCl 0.15 mol L-1 and then partially fractionated by using affinity chromatography performed on a trypsin-Sepharose 4B. These inhibitors presented different affinities between trypsin and chymotrypsin serine proteases, showing a higher inhibition to trypsin compared to chymotrypsin, except for P. nitida, which showed high inhibition against both enzymes. The SDS-PAGE analysis showed that the species from Parkia genus have a main band corresponding to partially purified trypsin inhibitors. The apparent molecular mass inhibitors (approximately 13-18 kDa) and the high specificity for trypsin suggest the occurrence of Bowman-Birk and Kunitz type inhibitors. Sementes de leguminosas (Fabaceae) apresentam alto conteúdo de inibidores, incluindo os inibidores de serinoproteinases que têm sido extensivamente estudados. Todavia, poucos estudos foram realizados quanto à investigação dessas proteínas em espécies arbóreas pertencentes à flora amazônica. As proteínas presentes nas sementes de quatro espécies de leguminosas da Amazônia, Parkia pendula, P. discolor, P. multijuga e P. nitida, foram obtidas pela extração usando NaCl 0.15 mol L-1 e, parcialmente purificadas usando a cromatografia de afinidade em tripsina-Sepharose 4B. Os inibidores exibiram afinidades diferentes entre a tripsina e a quimotripsina, exceto para P. nitida, a qual apresentou alta inibição contra as duas enzimas. A análise em SDS-PAGE mostrou que as espécies do gênero Parkia contém uma banda principal correspondendo aos inibidores de tripsina parcialmente purificados. As massas moleculares aparentes determinadas para os inibidores (aproximadamente, 13 a 18 kDa) e a alta especificidade pela tripsina sugerem a ocorrência de inibidores do tipo Bowman-Birk e Kunitz.

Crude venom ofBothrops jararacussuand isolated phospholipases A2(PLA2) of this toxin (BthTX-I and BthTX-II) were chemically modified (alkylation) byp-bromophenacyl bromide (BPB) in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2native and alkylated). BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR) data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2(PLA2) diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.

Bothrops mattogrossensissnake 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 PLA2homologues. 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 fromBothropsspecies. 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 ofLeishmania 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.

Crotoxin is a neurotoxin from Crotalus durissus terrificus venom that shows immunomodulatory, anti-inflammatory, antimicrobial, antitumor and analgesic activities. Structurally, this toxin is a heterodimeric complex composed by a toxic basic PLA2 (Crotoxin B or CB) non-covalently linked to an atoxic non-enzymatic and acidic component (Crotapotin, Crotoxin A or CA). Several CA and CB isoforms have been isolated and characterized, showing that the crotoxin venom fraction is, in fact, a mixture of different molecules derived from the combination of distinct subunit isoforms. Intercro (IC) is a protein from the same snake venom which presents high similarity in primary structure to CB, indicating that it could be an another isoform of this toxin. In this work, we compare IC to the crotoxin complex (CA/CB) and/or CB in order to understand its functional aspects. The experiments with IC revealed that it is a new toxin with different biological activities from CB, keeping its catalytic activity but presenting low myotoxicity and absence of neurotoxic activity. The results also indicated that IC is structurally similar to CB isoforms, but probably it is not able to form a neurotoxic active complex with crotoxin A as observed for CB. Moreover, structural and phylogenetic data suggest that IC is a new toxin with possible toxic effects not related to the typical CB neurotoxin.

A bradykinin-potentiating peptide (BPP) from Amazon Bothrops atrox venom with m/z 1384.7386 was identified and characterized by collision induced dissociation (CID) using an ESI-MS/MS spectra obtained in positive ion mode on a hybrid Qq-oaTOF mass spectrometer, Xevo G2 QTof MS (Waters, Manchester, UK). De novo peptide sequence analysis of the CID fragmentation spectra showed the amino acid sequence ZKWPRPGPEIPP, with a pyroglutamic acid and theoretical monoisotopic m/z 1384.7378, which is similar to experimental data, showing a mass accuracy of 0.6 ppm. The peptide is homologous to other BPP from Bothrops moojeni and was named as BPP-BAX12.

BaltLAAO-I, an L-amino acid oxidase isolated from Bothrops alternatus, is a glycoprotein enzyme with a pI⿿5.3, 15% sugar and a related molecular mass of 66,000 Da in its monomeric form, and 123,000 Da in its dimeric form. The objective of this study is to describe the cytotoxicity activity induced by BaltLAAO-I isolated from Bothrops alternatus venom and its possible mechanism of action on tumor cells. Our results clearly depict that BaltLAAO-I has a strong selective cytotoxic activity on tumor cell lines (JURKAT, SK-BR-3 and B16F10). On the other hand, the results show low cytotoxicity on human peripheral blood mononuclear cells. Furthermore, our findings demonstrate that BaltLAAO-I induces the apoptosis of tumor cell lines through a cytotoxic activity exerted by a generation of reactive oxygen intermediates. All in all, the data indicate that LAAOs exert a selective cytotoxic role on tumor cells, demonstrating a great potential for future use in clinical therapy.

Phospholipases A2 (PLA2s) from snake venoms comprise a group of 14-18 kDa proteins, responsible for several toxic effects induced by the whole venom. Considering this, studies aiming at the search for natural inhibitors of these proteins are very important. The present work had as objectives the isolation and functional/structural characterization of a γ-type phospholipase A2 inhibitor (PLI) from Bothrops jararacussu snake plasma, named γBjussuMIP. This acidic glycoprotein was isolated in a high purity level through affinity chromatography on CNBr-Sepharose 4B coupled with BthTXII, showing a pI ∼ 5.5 and molecular weight of 23,500 for the monomer (determined by SDS-PAGE), and 160,000 for the oligomer (determined by molecular exclusion chromatography on Sephacryl S-200). The interaction between γBjussuMIP (MIP) and Phospholipase A2 (PLA2) was confirmed using circular dichroism (CD) and emission fluorescence techniques. The helical content of the 1:1 molar mixture was higher than that calculated for the addition of the spectra of the unbound proteins indicating binding. The emission fluorescence experiments pointed that Trp residues in PLA2 participate in proteins interaction as blue shift of 4 nm was observed. The γBjussuMIP cDNA, obtained by PCR of the liver of B. jararacussu snake, revealed 543 bp codifying for a mature protein of 181 amino acid residues. Alignment of its amino acid sequence with those of other snake γPLIs showed 89-94% of similarity. γBjussuMIP mainly inhibited the pharmacological properties of Asp49 PLA2s, such as phospholipase, anticoagulant, myotoxic, edema inducing, cytotoxic, bactericidal and lethal activities. In addition, it showed to be able to supplement Bothrops antivenom, potentiating its antimyotoxic effect. The aspects broached in this work will be able to provide complementary information on possible mechanisms of action, relating structure and function, which could result in a better understanding of the inhibitory effects induced by γBjussuMIP.

Screening for new bioactive peptides in South American anurans has been pioneered in frogs of the genus Phyllomedusa. All frogs of this genus have venomous skin secretions, i.e., a complex mixture of bioactive peptides against potential predators and pathogens that presumably evolved in a scenario of predator-prey interaction and defense against microbial invasion. For every new anuran species studied new peptides are found, with homologies to hormones, neurotransmitters, antimicrobials, and several other peptides with unknown biological activity. From Vittorio Erspamer findings, this genus has been reported as a "treasure store" of bioactive peptides, and several groups focus their research on these species. From 1966 to 2009, more than 200 peptide sequences from different Phyllomedusa species were deposited in UniProt and other databases. During the last decade, the emergence of high-throughput molecular technologies involving de novo peptide sequencing via tandem mass spectrometry, cDNA cloning, pharmacological screening, and surface plasmon resonance applied to peptide discovery, led to fast structural data acquisition and the generation of peptide molecular libraries. Research groups on bioactive peptides in Brazil using these new technologies, accounted for the exponential increase of new molecules described in the last decade, much higher than in any previous decades. Recently, these secretions were also reported as a rich source of multiple antimicrobial peptides effective against multidrug resistant strains of bacteria, fungi, protozoa, and virus, providing instructive lessons for the development of new and more efficient nanotechnological-based therapies for infectious diseases treatment. Therefore, novel drugs arising from the identification and analysis of bioactive peptides from South American anuran biodiversity have a promising future role on nanobiotechnology.

Snake venoms are rich and intriguing sources of biologically-active molecules that act on target cells, modulating a diversity of physiological functions and presenting promising pharmacological applications. Lys49 phospholipase A2 is one of the multifunctional proteins present in these complex secretions and, although catalytically inactive, has a variety of biological activities, including cytotoxic, antibacterial, inflammatory, antifungal activities. Herein, a Lys49 phospholipase A2, denominated CoaTx-II from Crotalus oreganus abyssus, was purified and structurally and pharmacologically characterized. CoaTx-II was isolated with a high degree of purity by a combination of two chromatographic steps; molecular exclusion and reversed-phase high performance liquid chromatography. This toxin is dimeric with a mass of 13868.2 Da (monomeric form), as determined by mass spectrometry. CoaTx-II is rich in Arg and Lys residues and displays high identity with other Lys49 PLA2 homologues, which have high isoelectric points. The structural model of dimeric CoaTx-II shows that the toxin is non-covalently stabilized. Despite its enzymatic inactivity, in vivo CoaTx-II caused local muscular damage, characterized by increased plasma creatine kinase and confirmed by histological alterations, in addition to an inflammatory activity, as demonstrated by mice paw edema induction and pro-inflammatory cytokine IL-6 elevation. CoaTx-II also presents antibacterial activity against gram negative (Pseudomonas aeruginosa 31NM, Escherichia coli ATCC 25922) and positive (Staphyloccocus aureus BEC9393 and Rib1) bacteria. Therefore, data show that this newly purified toxin plays a central role in mediating the degenerative events associated with envenomation, in addition to demonstrating antibacterial properties, with potential for use in the development of strategies for antivenom therapy and combating antibiotic-resistant bacteria. Elsevier

Snake venom is a complex mixture of active compounds consisting of 80–90% proteins and peptides that exhibit a variety of biological actions that are not completely clarified or identified. Of these, phospholipase A 2 is one of the molecules that has shown great biotechnological potential. The objectives of this study were to isolate, biochemically and biologically characterize a Lys49 phospholipase A 2 homologue from the venom of Bothrops neuwiedi urutu . The protein was purified after two chromatographic steps, anion exchange and reverse phase. The purity and relative molecular mass were assessed by SDS-PAGE, observing a molecular weight typical of PLA 2 s, subsequently confirmed by mass spectrometry obtaining a mass of 13,733 Da. As for phospholipase activity, the PLA 2 proved to be enzymatically inactive. The analyses by Edman degradation and sequencing of the peptide fragments allowed for the identification of 108 amino acid residues; this sequence showed high identity with other phospholipases A 2 from Bothrops snake venoms, and identified this molecule as a novel PLA 2 isoform from B . neuwiedi urutu venom, called BnuTX-I. In murine models, both BnuTX-I as well as the venom induced edema and myotoxic responses. The cytotoxic effect of BnuTX-I in murine macrophages was observed at concentrations above 12 μg/mL. BnuTX-I also presented antimicrobial activity against gram-positive and negative bacterial strains, having the greatest inhibitory effect on Pseudomonas aeruginosa . The results allowed for the identification of a new myotoxin isoform with PLA 2 structure with promising biotechnological applications.

This study describes the biochemical and functional characterization of a new metalloproteinase named BbMP-1, isolated from Bothrops brazili venom. BbMP-1 was homogeneous on SDS-PAGE, presented molecular mass of 22,933Da and pI 6.4. The primary structure was partially elucidated with high identity with others metalloproteinases from Viperidae venoms. The enzymatic activity on azocasein was evaluated in different experimental conditions (pH, temperature). A significant reduction in enzyme activity after exposure to chelators of divalent cations (EDTA), reducing agents (DTT), pH less than 5.0 or temperatures higher than 45 °C was observed. BbMP-1 showed activity on fibrinogen degrading Aα chain quickly and to a lesser extent the Bβ chain. Also demostrated to be weakly hemorrhagic, presenting however, significant myotoxic and edematogenic activity. The in vitro activity of BbMP-1 against Plasmodium falciparum showed an IC50 of 3.2 ± 2.0 μg/mL. This study may help to understand the pathophysiological effects induced by this group of toxin and their participation in the symptoms observed in cases of snake envenomation. Moreover, this result is representative for this group of proteins and shows the biotechnological potential of BbMP-1 by the demonstration of its antiplasmodial activity.

A 6.5 kDa serine protease inhibitor was purified by anion-exchange chromatography from the crude extract of the Inga umbratica seeds, containing inhibitor isoforms ranging from 6.3 to 6.7 kDa and protease inhibitors of approximately 19 kDa. The purified protein was characterized as a potent inhibitor against trypsin and chymotrypsin and it was named I. umbratica trypsin and chymotrypsin inhibitor (IUTCI). MALDI-TOF spectra of the IUTCI, in the presence of DTT, showed six disulfide bonds content, suggesting that this inhibitor belongs to Bowman-Birk family. The circular dichroism spectroscopy indicates that IUTCI is predominantly formed by unordered and beta-sheet secondary structure. It was also characterized, by fluorescence spectroscopy, as a stable protein at range of pH from 5.0 to 7.0. Moreover, this inhibitor at concentration of 75 microM presented a remarkable inhibitory activity (60%) against digestive serine proteases from boll weevil Anthonomus grandis, an important economical cotton pest.

The thermal stability of a Schizolobium parahyba chymotrypsin inhibitor (SPCI) as a function of pH has been investigated using fluorescence, circular dichroism, and differential scanning calorimetry (DSC). The thermodynamic parameters derived from all methods are remarkably similar and strongly suggest the high stability of SPCI under a wide range of pH. The transition temperature (T(m)) values ranging from 57 to 85.3 degrees C at acidic, neutral, and alkaline pH are in good agreement with proteins from mesophilic and thermophilic organisms and corroborate previous data regarding the thermal stability of SPCI. All methods gave transitions curves adequately fitted to a two-state model of the unfolding process as judged by the cooperative ratio between the van't Hoff and the calorimetric enthalpy energies close to unity in all of the pH conditions analyzed, except at pH 3.0. Thermodynamic analysis using all these methods reveals that SPCI is thermally a highly stable protein, over the wide range of pH from 3.0 to 8.8, exhibiting high stability in the pH region of 5.0-7.0. The corresponding maximum stabilities, DeltaG(25), were obtained at pH 7.0 with values of 15.4 kcal mol(-1) (combined fluorescence and circular dichroism data), and 15.1 kcal mol(-1) (DSC), considering a DeltaC(p) of 1.72 +/- 0.24 kcal mol(-1) K(-1). The low histidine content ( approximately 1.7%) and the high acidic residue content ( approximately 22.5%) suggests a flat pH dependence of thermal stability in the region 2.0-8.8 and that the decrease in thermal stability at low pH can be due to the differences in pK values of the acidic groups.

Schizolobium parahyba chymotrypsin inhibitor (SPCI) was completely purified as a single polypeptide chain with two disulfide bonds, by TCA precipitation and ion exchange chromatography. This purification method is faster and more efficient than that previously reported: SPCI is stable from pH 2 to 12 at 25 degrees C, and is highly specific for chymotrypsin at pH 7-12. It weakly inhibits elastase and has no significant inhibitory effect against trypsin and alpha-amylase. SPCI is a thermostable protein and resists thermolysin digestion up to 70 degrees C.

Synthetic compounds derived from cinnamic acid were tested in cultures containing the promastigote form of Leishmania amazonensis and the dimethylsulphoxide solution of B2 compound (2.0 mg/mL) led to a 92% decrease of leishmania in 96 h of treatment. Then, different liposomal systems (diameters ∼200 nm) were prepared by the extrusion method in the presence and absence of compounds studied. DSC thermograms of the liposomes in the presence of these compounds caused changes in ΔH, Tm and ΔT1/2, compared to controls, indicating that there was an interaction of the compounds with the lipid bilayer. Assays with negatively charged liposomal systems containing these drugs in L. amazonensis cultures led to a 50–80% decrease in the number of leishmanias with a concentration to 100 times lower when compared to the B2 initial test. These liposomal systems are promoting more interaction and delivery of the compounds and proved to be an efficient, stable and promising system.

In this paper, we describe the purification/characterization of BmooAi, a new toxin fromBothrops moojenithat 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.

Background Mosquitoes are important vectors of several diseases, including malaria and dengue, and control measures are mostly performed using chemical insecticides. Unfortunately, mosquito resistance to commonly applied insecticides is widespread. Therefore, a prospection for new molecules with insecticidal activity based on Amazon biodiversity using the anurans Leptodactylus knudseni and Phyllomedusa vaillantii was performed against the mosquito species Anopheles darlingi and Aedes aegypti. Methods The granular secretion from anuran skin was obtained by manual stimulation, and lethal concentrations (LCs) for larvicidal and adulticidal tests were calculated using concentrations from 1-100 ppm. The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. Results The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. The calculated LC50 of L. knudseni skin secretions against An. darlingi was 0.15 and 0.2 ppm for adults and larvae, respectively, but much higher for Ae. aegypti, i.e., 19 and 38 ppm, respectively. Interestingly, the calculated LCs50 of P. vaillantii against both mosquito species in adults were similar, 1.8 and 2.1 ppm, respectively, but the LC50 for An. darlingi larvae was much lower (0.4 ppm) than for Ae aegypti (2.1 ppm). Conclusions The present experiments indicate that skin secretions from L. knudseni and P. vaillantii contain bioactive molecules with potent insecticide activity. The isolation and characterization of skin secretions components will provide new insights for potential insecticidal molecules.

Currently,Crotalus viridiswas divided into two species:Crotalus viridisandCrotalus oreganus. The current classification divides “the old”Crotalus viridisinto two new and independent species:Crotalus viridis(subspecies:viridis and nuntius) andCrotalus oreganus(subspecies:abyssus, lutosus, concolor, oreganus, helleri, cerberus, and caliginis). The analysis of a product from cDNA (E6d), derived from the gland of a specieCrotalus viridis viridis, was found to produce an acid phospholipase A2. In this study we isolated and characterized a PLA2(D49) fromCrotalus oreganus abyssusvenom. Our studies show that the PLA2produced from the cDNA ofCrotalus viridis viridis(named E6d) is exactly the same PLA2primary sequence of amino acids isolated from the venom ofCrotalus oreganus abyssus. Thus, the PLA2from E6d cDNA is actually the same PLA2presented in the venom ofCrotalus oreganus abyssusand does not correspond to the venom fromCrotalus viridis viridis. These facts highlight the importance of performing more studies on subspecies ofCrotalus oreganusandCrotalus viridis, since the old classification may have led to mixed results or mistaken data.

In the present study, we investigated thein vitroeffects 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 fromBothrops atroxsnake 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 BaPLA2induced 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 BaPLA2increased the number of lipid bodies on macrophages submitted to phagocytosis and not submitted to phagocytosis. However, BaTX-II and BaPLA2induced the release of TNF-αby 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.

This paper presents a novel serine protease (SP) isolated fromBothrops 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 Cu2+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 fromBothrops pirajaisnake venom.

In addition to conventional antibodies, camelids produce immunoglobulins G composed exclusively of heavy chains in which the antigen binding site is formed only by single domains called VHH. Their particular characteristics make VHHs interesting tools for drug-delivery, passive immunotherapy and high-throughput diagnosis. Hantaviruses are rodent-borne viruses of the Bunyaviridae family. Two clinical forms of the infection are known. Hemorrhagic Fever with Renal Syndrome (HFRS) is present in the Old World, while Hantavirus Pulmonary Syndrome (HPS) is found on the American continent. There is no specific treatment for HPS and its diagnosis is carried out by molecular or serological techniques, using mainly monoclonal antibodies or hantavirus nucleoprotein (N) to detect IgM and IgG in patient serum. This study proposes the use of camelid VHHs to develop alternative methods for diagnosing and confirming HPS. Phage display technology was employed to obtain VHHs. After immunizing one Lama glama against the recombinant N protein (prND85) of a Brazilian hantavirus strain, VHH regions were isolated to construct an immune library. VHHs were displayed fused to the M13KO7 phage coat protein III and the selection steps were performed on immobilized prND85. After selection, eighty clones recognized specifically the N protein. These were sequenced, grouped based mainly on the CDRs, and five clones were analyzed by western blot (WB), surface plasmon resonance (SPR) device, and ELISA. Besides the ability to recognize prND85 by WB, all selected clones showed affinity constants in the nanomolar range. Additionaly, the clone KC329705 is able to detect prND85 in solution, as well as the native viral antigen. Findings support the hypothesis that selected VHHs could be a powerful tool in the development of rapid and accurate HPS diagnostic assays, which are essential to provide supportive care to patients and reduce the high mortality rate associated with hantavirus infections.

Bothrops asper(Squamata: Viperidae) is the most important venomous snake in Central America, being responsible for the majority of snakebite accidents. Four basic PLA2s (pMTX-I to -IV) were purified from crude venom by a single-step chromatography using a CM-Sepharose ion-exchange column (1.5 × 15 cm). Analysis of the N-terminal sequence demonstrated that pMTX-I and III belong to the catalytically active Asp49 phospholipase A2subclass, whereas pMTX-II and IV belong to the enzymatically inactive Lys49 PLA2s-like subclass. The PLA2s isolated from PanamaBothrops aspervenom (pMTX-I, II, III, and IV) are able to induce myotoxic activity, inflammatory reaction mainly leukocyte migration to the muscle, and induce J774A.1 macrophages activation to start phagocytic activity and superoxide production.

The antihyperglycemic effects of several plant extracts and herbal formulations which are used as antidiabetic formulations have been described and confirmed to date. The main objective of this work was to evaluate the hypoglycemic activity of the aqueous extract ofAnacardium humile. Although the treatment of diabetic animals withA. humiledid not alter body weight significantly, a reduction of the other evaluated parameters was observed. Animals treated withA. humiledid not show variation of insulin levels, possibly triggered by a mechanism of blood glucose reduction. Levels of ALT (alanine aminotransferase) decreased in treated animals, suggesting a protective effect on liver. Levels of cholesterol were also reduced, indicating the efficacy of the extract in reestablishing the balance of nutrients. Moreover, a kidney protection may have been achieved due to the partial reestablishment of blood glucose homeostasis, while no nephrotoxicity could be detected forA. humile. The obtained results demonstrate the effectiveness ofA. humileextracts in the treatment of alloxan-induced diabetic rats. Therefore,A. humileaqueous extract, popularly known and used by diabetic patients, induced an improvement in the biochemical parameters evaluated during and following treatment of diabetic rats. Thus, a better characterization of the medicinal potential of this plant will be able to provide a better understanding of its mechanisms of action in these pathological processes.

Antivenoms, produced using animal hyperimmune plasma, remains the standard therapy for snakebites. Although effective against systemic damages, conventional antivenoms have limited efficacy against local tissue damage. Additionally, the hypersensitivity reactions, often elicited by antivenoms, the high costs for animal maintenance, the difficulty of producing homogeneous lots, and the instability of biological products instigate the search for innovative products for antivenom therapy. In this study, camelid antibody fragments (VHH) with specificity to Bothropstoxin I and II (BthTX-I and BthTX-II), two myotoxic phospholipases from Bothrops jararacussu venom, were selected from an immune VHH phage display library. After biopanning, 28 and 6 clones recognized BthTX-I and BthTX-II by ELISA, respectively. Complementarity determining regions (CDRs) and immunoglobulin frameworks (FRs) of 13 VHH-deduced amino acid sequences were identified, as well as the camelid hallmark amino acid substitutions in FR2. Three VHH clones (KF498607, KF498608, and KC329718) were capable of recognizing BthTX-I by Western blot and showed affinity constants in the nanomolar range against both toxins. VHHs inhibited the BthTX-II phospholipase A2 activity, and when tested for cross-reactivity, presented specificity to the Bothrops genus in ELISA. Furthermore, two clones (KC329718 and KF498607) neutralized the myotoxic effects induced by B. jararacussu venom, BthTX-I, BthTX-II, and by a myotoxin from Bothrops brazili venom (MTX-I) in mice. Molecular docking revealed that VHH CDRs are expected to bind the C-terminal of both toxins, essential for myotoxic activity, and to epitopes in the BthTX-II enzymatic cleft. Identified VHHs could be a biotechnological tool to improve the treatment for snake envenomation, an important and neglected world public health problem.

In the present study, micronucleus with cytokinesis blocking and comet assays were used to evaluate the genotoxic potential of Bothrops jararacussu, Bothrops atrox, Bothrops moojeni, Bothrops alternatus (Rhinocerophis alternatus) and Bothrops brazili snake venoms, and also of some isolated toxins (MjTX-I, BthTX-I and II myotoxins, BjussuMP-II metalloprotease, and BatxLAAO l-amino acid oxidase) on human lymphocytes. Significant DNA damages were observed, indicating genotoxic potential after exposure of the lymphocytes to the toxins BthTX-I, II and BatxLAAO compared to untreated and Cisplatin-treated controls, which were able to induce greater formation of micronuclei. B. brazili, B. jararacussu and B. atrox crude venoms also presented genotoxic potential, and the latter two induced DNA breakage 5 times more often than in normal environmental conditions (control without treatment). B. jararacussu venom and its isolated toxins, as well as an LAAO from B. atrox, were able to cause lymphocyte DNA breakage in the comet test with more than 85% damage levels. The DNA damage evaluation allows a widening of the toxic-pharmacological characterization of snake venoms and their toxins and also contributes to the understanding of the mechanisms of action of these molecules in several human pathologies.

Leishmanicidal activity of the 3-(3,4,5-trimethoxyphenyl) propanoic acid (TMPP) isolated from EtOH extracts of the Amazonian Piper turbeculatum Jacq. fruits was evaluated in vitro using Leishmania amazonensis promastigotes. The TMPP was assayed at concentrations of 1600 to 6.25 µg/mL for 24, 48, 72 and 96 h. Promastigotes viability was analyzed and the IC50 of TMPP was 145 µg/mL. A atividade leishmanicida do ácido 3,4,5-trimetoxi-dihidrocinâmico (TMPP) isolado do extrato hidroalcoólico de frutos de Piper turbeculatum Jacq. amazônica foi testado em ensaios in vitro utilizando formas promastigotas de Leishmania amazonensis. O TMPP foi utilizado em culturas de L. amazonensis nas concentrações de 1600 a 6,25 µg/mL. A viabilidade celular das formas promastigotas foi observada em 24, 48, 72 e 96 h para cálculo da CI50. O TMPP apresentou efeito leishmanicida dose dependente para as formas promastigotas de L. amazonensis apresentando CI50 de 145 µg/mL.

Inga cylindrica Trypsin Inhibitor (ICTI) was purified as a single polypeptide chain by one step anion-exchange chromatography from a crude extract of Inga cylindrica (Vell.) Mart. seeds. ICTI is a 19.5 kDa protein presenting a remarkable inhibitory activity against bovine trypsin (EC 3.4.21.4) (Ki = 4.3 nM). Circular dichroism analysis revealed that this inhibitor is a β type protein (40.4% of β-strand; 24.6% of β-turn and 6.7% of α-helix) in accordance with properties displayed in Kunitz type inhibitors. ICTI is a thermal stable protein within a wide range of pH (1.6 to 10.0) exhibiting highest stability at pH 7.0 as indicated by Tm of 70.0 oC and ΔG25 of 48.5 ± 0.7 kJ.mol-1. The values of ΔG25 at pH 1.6 (22.5 ± 1.2 kJ.mol-1) and pH 10.0 (31.5 ± 1.0 kJ.mol-1) indicate a reduced structural stability of the protein under these conditions. This is likely to result from pKa differences of the acid and basic side chains reflecting the changes in the non-covalent interactions in the folded state.

None

and the Amazonian forest biomes. Two specimens of this species were collected at Porto Velho, Rondonia, in anthropized areas near Governador Jorge Teixeira de Oliveira International Airport (08°43'60'' S, 63°53'60'' W, LAC, 5 October 2008) and in the Santo Antonio Furnas hydroelectric power plant area (08°48'35'' S, 63°57'13'' W, MRM, 11 November 2008, Figure 2). Specimens were identified according to the diagnosis presented by Caramaschi (2006), and are deposited in the anuran collection of the

Phospholipases A2(PLA2s) constitute a class of extensively studied toxins, isolated from snake venoms.Basic PLA2isoforms mediate various toxicological effects, while the acidic isoforms generally have higherenzymatic activities, but do not promote evident toxic effects. The functions of these acidic isoforms insnake venoms are still not completely understood and more studies are needed to characterize thebiological functions and diversification of acidic toxins in order to justify their abundant presence inthese secretions. Recently, Lomonte and collaborators demonstrated, in a proteomic and toxicologicalstudy, high concentrations of PLA2s in the venom ofAgkistrodon piscivorus leucostoma.We have, herein,purified and characterized an acidic PLA2from this snake venom, denominated AplTx-I, in order to betterunderstand its biochemical and structural characteristics, as well as its biological effects. AplTx-I waspurified using two chromatographic steps, in association with enzymatic and biological assays. The acidictoxin was found to be one of the most abundant proteins in the venom ofA. p. leucostoma;the proteinwas monomeric with a molecular mass of 13,885.8 Da, as identified by mass spectrometry ESI-TOF andelectrophoresis. The toxin has similar primary and tridimensional structures to those of other acidicPLA2s, a theoretical and experimental isoelectric point ofz5.12, and a calcium-dependent enzyme ac-tivity of 25.8985 nM/min/mg, with maximum values at 37 C and pH 8.0. Despite its high enzymaticactivity on synthetic substrate, AplTx-I did not induce high or significant myotoxic, coagulant, antico-agulant, edema, neuromuscular toxicity in mouse phrenic nerve-diaphragm preparations or antibacterialactivities. Interestingly, AplTx-I triggered a high and selective neuromuscular toxicity in chickbiventercervicispreparations. Thesefindings are relevant to provide a deeper understanding of the pharma-cology, role and diversification of acidic phospholipase A2isoforms in snake venoms.