Bioactive small molecules isolated from animals, plants, fungi and bacteria, including natural antimicrobial peptides, have shown great therapeutic potential worldwide. Among these peptides, snake venom cathelicidins are being widely exploited, because the variation in the composition of the venom reflects a range of biological activities that may be of biotechnological interest. Cathelicidins are short, cationic, and amphipathic molecules. They play an important role in host defense against microbial infections. We are currently facing a strong limitation on pharmacological interventions for infection control, which has become increasingly complex due to the lack of effective therapeutic options. In this review, we will focus on natural snake venom cathelicidins as promising candidates for the development of new antibacterial agents to fight antibiotic-resistant bacteria. We will highlight their antibacterial and antibiofilm activities, mechanism of action, and modulation of the innate immune response.

Several antimicrobial peptides (AMPs) have been reported in amphibian toxins, as temporin‐PTa from Hylarana picturata. The amino acid distribution within a helical structure of AMPs favors the design of new bioactive peptides. Therefore, this work reports the rational design of two new synthetic peptides denominated Hp‐MAP1 and Hp‐MAP2 derived from temporin‐PTa. These peptides present an amphipathic helix with positive charges of +4 and +5, hydrophobic moment (<µH>) of 0.66 and 0.72 and hydrophobicity () of 0.49 and 0.41, respectively. Hp‐MAP1 and Hp‐MAP2 displayed in vitro activity against Gram‐negative and Gram‐positive bacteria from 2.8 to 92 µM, without presenting hemolytic effects. Molecular dynamics simulation suggested that the parent and designed temporin‐like peptides lack structural stability in an aqueous solution. By contrast, α‐helical structures were predicted in hydrophobic and anionic environments. Additionally, the peptides were simulated on mimetic membranes composed of anionic and neutral phospholipids 1,2‐dipalmitoylsn‐glycerol‐3‐phosphatidylglycerol (DPPG‐anionic), 1,2‐dipalmitoyl‐sn‐lyco‐3 phosphatidylethanolamine (DPPE‐neutral). When in contact with DPPG/DPPE (90:10) and DPPG/DPPE (50:50) temporin‐PTa, Hp‐MAP1 and Hp‐MAP2 established interactions guided by hydrogen and saline bounds. Therefore, the findings described here reveal that the optimization of the amphipathic α‐helical cationic peptides Hp‐MAP1 and Hp‐MAP2 enabled the generation of new synthetic antimicrobial agents to combat pathogenic microorganisms.

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Introduction: Bacterial resistance is a worldwide public health problem, requiring new therapeutic options. An alternative approach to this problem is the use of animal toxins isolated from snake venom, such as phospholipases A2 (PLA2), which have important antimicrobial activities. Bothropserythromelas is one of the snake species in the northeast of Brazil that attracts great medical-scientific interest. Here, we aimed to purify and characterize a PLA2 from B. erythromelas, searching for heterologous activities against bacterial biofilms. Methods: Venom extraction and quantification were followed by reverse-phase high-performance liquid chromatography (RP-HPLC) in C18 column, matrix-assisted ionization time-of-flight (MALDI-ToF) mass spectrometry, and sequencing by Edman degradation. All experiments were monitored by specific activity using a 4-nitro-3-(octanoyloxy) benzoic acid (4N3OBA) substrate. In addition, hemolytic tests and antibacterial tests including action against Escherichiacoli, Staphylococcusaureus, and Acinetobacterbaumannii were carried out. Moreover, tests of antibiofilm action against A. baumannii were also performed. Results: PLA2, after one purification step, presented 31 N-terminal amino acid residues and a molecular weight of 13.6564 Da, with enzymatic activity confirmed in 0.06 µM concentration. Antibacterial activity against S. aureus (IC50 = 30.2 µM) and antibiofilm activity against A. baumannii (IC50 = 1.1 µM) were observed. Conclusions: This is the first time that PLA2 purified from B. erythromelas venom has appeared as an alternative candidate in studies of new antibacterial medicines.

Introduction: Bacterial resistance is a worldwide public health problem, requiring new therapeutic options. An alternative approach to this problem is the use of animal toxins, such as phospholipases (PLA2) isolated from snake venom, which have important biological activities. Bothrops erythromelas is one of the snake species in the Northeast of Brazil that attracts great medical-scientific interest. Here we aimed to purify and characterize a PLA2 from B. erythromelas, searching for heterologous activities against bacterial biofilm. Methods: Venom extraction and quantification were followed by RP-HPLC in C18 column, MALDI-ToF mass spectrometry and sequencing by Edman degradation. All experiments were monitored by specific activity using 4-nitro-3 (octanoyloxy) benzoic acid (4N3OBA) substrate. In addition, hemolytic tests and anti-bacterial tests including action against Escherichia coli, Staphylococcus aureus and Acinetobacter baumannii, were carried out. Moreover, tests of antibiofilm action against A. baumannii were also performed. Results: PLA2, after one purification step, presented 31 N-terminal amino acid residues, and molecular weight of 13656.4 Da with enzymatic activity confirmed in 0.06 &micro;M concentration. Antibacterial activity against S. aureus (IC50 = 30.2 &micro;M) and antibiofilm activity against A. baumannii (IC50 = 1.1 &micro;M) were observed. Conclusions: This is the first time that PLA2 purified from B. erythromelas venom has appeared as an alternative candidate in studies of new antibacterial medicines.

O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais. Conselho Editorial Ciências Humanas e Sociais Aplicadas APRESENTAÇÃO A obra intitulada "Prospecção de moléculas bioativas em animais e plantas: uma visão biotecnológica" consiste em uma coletânea de artigos científicos apresentados em 9 capítulos, com enfoque em biotecnologia. Na mesma, foram expostos conhecimentos sobre bioquímica, microbiologia e bioinformática, com estudos em diferentes espécies, abrangendo a biodiversidade brasileira. Na biotecnologia, os campos de estudos são muito amplos e englobam pesquisas complexas envolvendo microrganismos, plantas e animais. Desta forma, a obra apresenta pesquisas sobre moléculas bioativas derivadas de aracnídeos, insetos, répteis, anfíbios e plantas. Essas moléculas bioativas apresentam uma gama de atividades biológicas, e algumas dessas, com potencial antimicrobiano, inibidores de peptidases, entre outras, foram apresentadas no decorrer da obra. Ademais, moléculas protéicas bioativas provenientes de fontes naturais, podem ter sua sequencias primárias caracterizadas e modificada por meio da bioinformática (metodologia de desenho racional), que busca melhorar seu potencial terapêutico in vitro partindo de estudos in silico. As informações geradas nesta obra são de extrema relevância em nível acadêmico, pois mostra pesquisas básicas avançando para pesquisas aplicadas, o que proporciona o enriquecimento da comunidade científica e formação profissional de alunos de graduação e pós graduação.

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