Comparative venomic profiles of three spiders of the genus Phoneutria

Spider venoms induce different physio-pharmacological effects by binding with high affinity on molecular targets, therefore being of biotechnological interest. Some of these toxins, acting on different types of ion channels, have been identified in the venom of spiders of the genus Phoneutria, mainly from P. nigriventer. In spite of the pharmaceutical potential demonstrated by P. nigriventer toxins, there is limited information on molecules from venoms of the same genus, as their toxins remain poorly characterized. Understanding this diversity and clarifying the differences in the mechanisms of action of spider toxins is of great importance for establishing their true biotechnological potential. This prompted us to compare three different venoms of the Phoneutria genus: P. nigriventer (Pn-V), P. eickstedtae (Pe-V) and P. pertyi (Pp-V). Methods: Biochemical and functional comparison of the venoms were carried out by SDS-PAGE, HPLC, mass spectrometry, enzymatic activities and electrophysiological assays (whole-cell patch clamp). Results: The employed approach revealed that all three venoms had an overall similarity in their components, with only minor differences. The presence of a high number of similar proteins was evident, particularly toxins in the mass range of ~6.0 kDa. Hyaluronidase and proteolytic activities were detected in all venoms, in addition to isoforms of the toxins Tx1 and Tx2-6. All Tx1 isoforms blocked Nav1.6 ion currents, with slight differences. Conclusion: Our findings showed that Pn-V, Pe-V and Pp-V are highly similar concerning protein composition and enzymatic activities, containing isoforms of the same toxins sharing high sequence homology, with minor modifications. However, these structural and functional variations are very important for venom diversity. In addition, our findings will contribute to the comprehension of the molecular diversity of the venoms of the other species from Phoneutria genus, exposing their biotechnological potential as a source for searching for new active molecules.(AU)

Comparative venomic profiles of three spiders of the genus Phoneutria

Abstract Background: Spider venoms induce different physio-pharmacological effects by binding with high affinity on molecular targets, therefore being of biotechnological interest. Some of these toxins, acting on different types of ion channels, have been identified in the venom of spiders of the genus Phoneutria, mainly from P. nigriventer. In spite of the pharmaceutical potential demonstrated by P. nigriventer toxins, there is limited information on molecules from venoms of the same genus, as their toxins remain poorly characterized. Understanding this diversity and clarifying the differences in the mechanisms of action of spider toxins is of great importance for establishing their true biotechnological potential. This prompted us to compare three different venoms of the Phoneutria genus: P. nigriventer (Pn-V), P. eickstedtae (Pe-V) and P. pertyi (Pp-V). Methods: Biochemical and functional comparison of the venoms were carried out by SDS-PAGE, HPLC, mass spectrometry, enzymatic activities and electrophysiological assays (whole-cell patch clamp). Results: The employed approach revealed that all three venoms had an overall similarity in their components, with only minor differences. The presence of a high number of similar proteins was evident, particularly toxins in the mass range of ~6.0 kDa. Hyaluronidase and proteolytic activities were detected in all venoms, in addition to isoforms of the toxins Tx1 and Tx2-6. All Tx1 isoforms blocked Nav1.6 ion currents, with slight differences. Conclusion: Our findings showed that Pn-V, Pe-V and Pp-V are highly similar concerning protein composition and enzymatic activities, containing isoforms of the same toxins sharing high sequence homology, with minor modifications. However, these structural and functional variations are very important for venom diversity. In addition, our findings will contribute to the comprehension of the molecular diversity of the venoms of the other species from Phoneutria genus, exposing their biotechnological potential as a source for searching for new active molecules.

Funcionalização do polietilenoglicol metil éter via reação de bromoacetilação: ativação, caracterização por MALDI-TOF e mecanismo de reação / Poly(ethylene glycol) methyl ether functionalization by bromoacetylation reaction: Activation, characterization by MALDI-TOF and reaction mechanism / Funcionalización de polietilenglicol metil éter mediante reacción de bromoacetilación: activación, caracterización por MALDI-TOF y mecanismo de reacción

Resumo A PEGuilação, reação química de conjugação com a molécula de polietilenoglicol (PEG) ou polietilenoglicol metil éter (mPEG), tem sido amplamente aplicada pelas indústrias farmacêuticas como estratégia de melhoria das propriedades farmaco-cinéticas de compostos bioativos. O PEG é um polímero que possui um esqueleto de poliéter quimicamente inerte e que apresenta grupos hidroxilas (-OH) em suas extremidades. Assim, o PEG para tornar-se apto como reagente de conjugação deve ser ativado com um grupo funcional que seja reativo. Nesse sentido, a bromoaceti-lação apresenta-se como uma alternativa para a funcionalização do PEG. Portanto, nesse trabalho objetivamos descrever em detalhes os procedimentos e o mecanismo de reação envolvida na funcionalização do mPEG, através da reação de bromoacetilação. Além do mais, estudamos a aplicação do MALDI-ToF para a caracterização do produto ativado. Após a bromoacetilação, por um procedimento adaptado, obteve-se o bromoacetil-mPEG-éster, com rendimento bruto de 56,78%. Análises posteriores, por espectrometria de massas por MALDI-ToF, possibilitaram identificar e caracterizar o produto bromoacetilado. Entre as condições de reação, o controle de temperatura (-10 °C a 0 °C) mostrou-se eficaz favorecendo a adição nucleofílica essencial à bromoacetilação. Assim, concluímos que o controle da baixa temperatura reacional é um fator chave para o favorecimento da adição nucleofílica à carbonila e, portanto, essencial na obtenção do mPEG funcionalizado via bromoacetilação. Estudos posteriores serão necessários, no entanto, para confirmar se o mPEG esterificado, nessas condições, poderá ser utilizado na conjugação com moléculas de natureza proteica ou peptídica, por meio de substituição nucleofílica bimolecular.

SUMMARY PEGylation, a chemical reaction of conjugation with the polyethylene glycol molecule (PEG), has been widely applied by the pharmaceutical industries as a strategy to improve the pharmacokinetic properties of bioactive compounds. PEG is a polymer that has a chemically inert polyether backbone and hydroxyl groups (-OH) at its ends. Thus, PEG to become fit as a reagent for conjugation must be activated with a functional group that is reactive. In this sense, bromoacetylation presents itself as an alternative for the functionalization of PEG. Therefore, in this study we aim to describe in detail the procedures and reaction mechanism involved in the functionalization of mPEG through the bromoacetylation reaction. In addition, we used the spectrometric technique, by MALDI-ToF, for the characterization of the activated product. After applying an adapted bromoacetylation procedure, bromoacetyl-mPEG-ester was obtained with a yield of 56.78%. Subsequent analyzes of MALDI-ToF mass spectrometry were able to correctly identify and characterize the bromoacety-lated product. Among the reaction conditions, temperature control (from -10 °C to 0 °C) was effective in favoring the essential nucleophilic addition to bromoacetylation. Thus, we conclude that the control of the low reaction temperature is a key factor in favoring the nucleophilic addition to carbonyl and, therefore, obtaining a favorable conversion to functionalized PEG via bromoacetylation. Further studies, however, will be necessary to confirm whether PEG esterified with these conditions can be used in conjunction with molecules of a protein or peptide nature by means of bimolecular nucleophilic substitution.

RESUMEN La PEGilación, una reacción química de conjugación con la molécula de polietilenglicol (PEG), ha sido ampliamente aplicada por las industrias farmacéuticas como una estrategia para mejorar las propiedades farmacocinéticas de los compuestos bioactivos. El PEG es un polímero formado por un esqueleto de poliéter químicamente inerte con grupos hidroxilo (-OH) en sus extremos. Por lo tanto, para usar el PEG como reactivo de conjugación debe activarse con un grupo funcional que sea reactivo. En este sentido, la bromoacetilación es una alternativa para la funcionalización de PEG. De esta manera, en este trabajo nuestro objetivo es describir en detalle los procedimientos y el mecanismo de reacción involucrados en la funcionalización de PEG a través de la reacción de bromoacetilación. Además, estudiamos la aplicación de MALDI-ToF para la caracterización del producto activado. Después de aplicar un procedimiento de bromoacetilación adaptado, se obtuvo bromoacetil-mPEG-éster con un rendimiento bruto de 56,78%. Los análisis posteriores de espectrometría de masas por MALDI-ToF pudieron identificar y caracterizar correctamente el producto bromoacetilado. Entre las condiciones de reacción, el control de la temperatura (desde -10 °C hasta 0 °C) fue eficaz para favorecer la adición nucleofílica esencial a la bromoacetilación. Así, concluimos que el control de la baja temperatura de reacción es un factor clave para favorecer la adición nucleofílica al carbonilo y, por lo tanto, esencial para obtener el mPEG funcionalizado mediante la bromoacetilación. Sin embargo, serán necesarios más estudios para confirmar si el mPEG esterificado en estas condiciones puede usarse junto con moléculas de naturaleza proteica o peptídica por medio de la sustitución nucleófila bimolecular.

Antinociceptive effect of PnTx4(5-5), a peptide from Phoneutria nigriventer spider venom, in rat models and the involvement of glutamatergic system

The venom of Phoneutria nigriventer spider is a source of numerous bioactive substances, including some toxins active in insects. An example is PnTx4(5-5) that shows a high insecticidal activity and no apparent toxicity to mice, although it inhibited NMDA-evoked currents in rat hippocampal neurons. In this work the analgesic activity of PnTx4(5-5) (renamed Γ-ctenitoxin-Pn1a) was investigated. Methods: The antinociceptive activity was evaluated using the paw pressure test in rats, after hyperalgesia induction with intraplantar injection of carrageenan or prostaglandin E2 (PGE2). Results: PnTx4(5-5), subcutaneously injected, was able to reduce the hyperalgesia induced by PGE2 in rat paw, demonstrating a systemic effect. PnTx4(5-5) administered in the plantar surface of the paw caused a peripheral and dose-dependent antinociceptive effect on hyperalgesia induced by carrageenan or PGE2. The hyperalgesic effect observed in these two pain models was completely reversed with 5 µg of PnTx4(5-5). Intraplantar administration of L-glutamate induced hyperalgesic effect that was significantly reverted by 5 μg of PnTx4(5-5) injection in rat paw. Conclusion: The antinociceptive effect for PnTx4(5-5) was demonstrated against different rat pain models, i.e. induced by PGE2, carrageenan or glutamate. We suggest that the antinociceptive effect of PnTx4(5-5) may be related to an inhibitory activity on the glutamatergic system.(AU)

Antibacterial activity of different types of snake venom from the Viperidae family against Staphylococcus aureus / Atividade antibacteriana de diferentes tipos de veneno de serpentes da família Viperidae contra Staphylococcus aureus

Toxins and venoms produced by living organisms have exhibited a variety of biological activities against microorganisms. In this study, we tested seven snake venoms from the family Viperidae for antibacterial activity and the activities of reversal of antibiotic resistance and inhibition of biofilm formation against 22 clinical isolates of Staphylococcus aureus. Bothrops moojeni venom exhibited anti staphylococcal activity with the lowest mean value of minimum inhibitory concentration (MIC). Moreover, reversal of antibiotic resistance was observed for combinations of B. moojeni venom (½ x MIC) and norfloxacin or ampicillin (both ½ x MIC) for 86.4% and 50% of the isolates, respectively. B. moojeni venom alone at ½ MIC inhibited 90% of biofilm formation, whereas in combination with ciprofloxacin, both at ½ MIC, a reduction on the NorA efflux pump activity was observed. The detection of in vitro mutants colonies of S. aureus resistant to B. moojeni venom was low and they did not survive. A phospholipase A2 was purified from the venom of B. moojeni and displayed anti-staphylococcal activity when tested alone or in combination with ciprofloxacin. The results presented here will contribute to the search for new antimicrobial agents against resistant S. aureus.

Toxinas e venenos exibem uma variedade de atividades biológicas contra micro-organismos. Neste estudo, investigou-se a atividade de sete venenos de serpentes, da família Viperidae, sobre o crescimento de Staphylococcus aureus, na reversão fenotípica da resistência a antibióticos e inibição de formação de biofilme contra 22 isolados clínicos de S. aureus. O veneno de Bothrops moojeni apresentou a menor média de concentração inibitória mínima (CIM). Além disso, observou-se reversão da resistência a antibióticos para combinações do veneno de B. moojeni (½ x CIM) e norfloxacina ou ampicilina (ambos ½ x CIM) para 86,4% e 50% dos isolados, respectivamente. O veneno de B. moojeni na concentração de ½ CIM inibiu 90% de formação de biofilme, enquanto ele em combinação com ciprofloxacina, ambos na concentração de ½ CIM, diminuiu a atividade da bomba de efluxo NorA. A detecção in vitro de colônias mutantes de S. aureus resistente ao veneno de B. moojeni foi baixa e eles não sobreviveram. Uma fosfolipase A2 purificada a partir do veneno de B. moojeni exibiu atividade antibacteriana quando testada sozinha ou em combinação com ciprofloxacina. Os dados obtidos poderão contribuir para a pesquisa de novos agentes antimicrobianos contra S. aureus.