No / A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1H-benzo[d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal activity against the selected fungal strains. They displayed equivalent or greater potency in their MIC values than amphotericin B. The 5-halobenzimidazole derivatives could be considered promising broad-spectrum antimicrobial candidates that deserve further study for potential therapeutic applications.

This thesis reports the syntheses and biological activities of benzo- and thieno-fused 7-deazapurine ribonucleosides, which were designed as extended analogues of potent cytostatic 6-hetaryl-7-deazapurine or 6-amino-7-hetaryl-7-deazapurine ribonucleosides. First of all, multigram syntheses of (di)chloro-9H-pyrimido[4,5-b]indoles from simple chloro- nitrobenzenes were developed. Pyrimidoindoles were successfully glycosylated and used for the synthesis of 4-hetaryl-6-chloro-, 4,6-bis(hetaryl)-, 4-amino-6-hetaryl-, 4-amino-5-hetaryl- and 4-susbtituted pyrimido[4,5-b]indole ribonucleosides. Hetaryl groups were introduced by Suzuki or Stille cross-coupling reaction. Standard catalysts and conditions were used for reaction in position 4. To observe some reactivity of unreactive chlorine in position 6, modification of standard protocol was necessary. Screening of several ligands had been done and Buchwald ligand X-Phos was found to be optimal. As chlorine in position 4 is activated for nucleophilic substitution, amino and dimethylamino derivatives were prepared by reaction with aqueous ammonia and dimethylamine, respectively. 4-Alkyl derivatives were synthesized by palladium-catalyzed alkylation with trialkylaluminium or by Negishi coupling in case of cyclopropyl derivative. Desired free nucleosides were...

Peptídeos antimicrobianos (AMP) são importantes componentes do sistema imune de todos os organismos vivos. No plasma de Acanthoscurria rondoniae isolamos 15 AMP com similaridade com a hemocianina. As sete subunidades da hemocianina foram sequenciadas e sua estrutura tridimensional determinada. A rondonina, processada a partir de uma enzima do plasma em condições ácidas apresentou melhor atividade em pH ácido, sinergismo com gomesina, não citotóxico, não interagiu com membranas artificiais lipídicas, protegeu as células da infecção por vírus humanos de RNA e seu mecanismo de ação em leveduras está associado com material genético. Nossos resultados nos ajudam a entender porque aracnídeos sobreviveram por um longo tempo na escala evolutiva. E como as doenças infecciosas estão entre as principais causas de morte da população humana torna-se vital investir na busca de substâncias naturais ou sintéticas que exibam atividades antimicrobianas específicas e, acima de tudo, que as exerçam através de mecanismos de ação alternativos daqueles dos antibióticos disponíveis. / Antimicrobial peptides (AMP) are important components of the immune system of all living organisms. In the plasma of Acanthoscurria rondoniae we isolated 15 AMP with similarity to hemocyanin. The seven subunits hemocyanin were sequenced and determined its three-dimensional structure. The rondonin, processed from a plasma enzyme under acidic conditions showed best activity at acid pH, synergism with gomesin, non-cytotoxic, does not interacted with lipid artificial membrane, protected the cells from infection by human virus RNA and its mechanism of action in yeast is associated with genetic material. Our results help us understand why arachnids have survived for a long time on the evolutionary scale. And how infectious diseases are among the leading causes of death in human population becomes vital to invest in the search for natural or synthetic substances that exhibit specific antimicrobial activities and, above all, that engage through alternative mechanisms of action of these antibiotics available.

Les maladies virales à transmission vectorielle émergentes et ré-émergentes comme la dengue, le chikungunya ou le zika sont responsables de nombreuses épidémies sévères à travers le monde. Récemment, la propagation rapide et très étendue du virus zika (ZIKV) ainsi que les complications neurologiques graves liées à l’infection par ZIKV ont incité l’Organisation Mondiale de la Santé (OMS) à déclarer le ZIKV comme une urgence de santé publique mondiale. Aujourd’hui, les mesures préventives ou curatives de l’infection par ZIKV sont quasiment inexistantes. D’autre part, la flore endémique de La Réunion est connue comme une source riche, renouvelable et prometteuse en produits naturels anti-infectieux. L’inscription à la pharmacopée française de 19 plantes médicinales réunionnaises souligne le potentiel thérapeutique des substances naturelles issues de la biodiversité locale. Les travaux ont été consacrés à l’identification de substances naturelles anti-ZIKV issues d’une sélection de sept plantes médicinales réunionnaises inscrites à la pharmacopée française. Dans une première étape, une extraction sans solvant assistée par micro-ondes a été appliquée sur les sept plantes médicinales sélectionnées afin d’obtenir des éco-extraits. Dans une deuxième étape, le criblage de l’activité antivirale, en utilisant un clone moléculaire du ZIKV avec un gène rapporteur, a permis d’identifier deux éco-extraits actifs provenant de Aphloia theiformis et de Psiloxylon mauritianum. Après avoir vérifié l’absence de cytotoxicité et de génotoxicité des extraits actifs, l’activité antivirale a été aussi démontrée sur d’autres types d’extraits réalisés via des méthodes d’extractions traditionnelles (infusion, décoction et macération). L’activité antivirale a été validée sur différentes souches de ZIKV (historique et épidémique) ainsi que sur les 4 sérotypes du virus de la dengue. Enfin, le mode d’action des deux extraits actifs a été étudié. Il a été montré que les éco-extraits d’A. theiformis et de P. mauritianum ciblent les phases précoces du cycle viral en inhibant l’attachement du virus à la cellule hôte. À l’aide de la microscopie électronique, il a été montré que l’éco-extrait d’A. theiformis déforme la particule virale empêchant cette dernière de s’attacher à la membrane de la cellule hôte. Ces résultats démontrent l’importance des plantes médicinales réunionnaises comme source de substances naturelles anti-infectieuses. / Emerging and re-emerging vector-borne viral diseases such as dengue, chikungunya or zika are responsible for many severe epidemics worldwide. Recently, the rapid spread of zika virus (ZIKV) worldwide and the serious neurological complications associated with ZIKV infection have prompted the World Health Organization (WHO) to declare ZIKV a public health emergency. Today, preventive or curative measures against ZIKV infection are almost non-existing. On the other hand, the endemic flora of Reunion Island is known as a rich, renewable and promising source of natural anti-infective products. The registration of 19 medicinal plants from Reunion Island in the French pharmacopoeia highlights the therapeutic potential of natural substances derived from local biodiversity. The work was dedicated to the identification of natural anti-ZIKV substances from a selection of seven medicinal plants from La Reunion registered in the French pharmacopoeia. In a first step, in collaboration with a local start-up (Bourbon Extracts), a solvent-free microwave-assisted extraction was applied to the seven selected plants in order to obtain eco-extracts. In a second step, the screening for antiviral activity, using a ZIKV molecular clone with a reporter gene, allowed the identification of two candidate plants: Aphloia theiformis and Psiloxylon mauritianum. After verifying the absence of cytotoxicity and genotoxicity of the active extracts, the antiviral activity was also demonstrated on other types of extracts using traditional extraction methods (infusion, decoction and maceration). The antiviral activity has been validated on different strains of ZIKV (historical and epidemic) as well as on the four serotypes of the dengue virus. Finally, the mode of action of the two active extracts has been studied. It has been shown that the eco-extracts from A. theiformis and P. mauritianum target the early steps of the viral cycle by inhibiting the attachment of the virus to the host cell. Using electron microscopy, it has been shown that the eco-extract of A. theiformis deforms the viral particle preventing its attachment to the membrane of the host cell. These results demonstrate the importance of medicinal plants from Reunion Island as a source of natural anti-infectious substances.

Submitted by Ubirajara Cruz (ubirajara.cruz@gmail.com) on 2017-05-08T14:44:48Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Cristina_Peter.pdf: 1012287 bytes, checksum: a6b5ae3184db955c29ee2d8a7adfa70f (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-05-08T14:56:02Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Cristina_Peter.pdf: 1012287 bytes, checksum: a6b5ae3184db955c29ee2d8a7adfa70f (MD5) / Made available in DSpace on 2017-05-08T14:56:02Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Cristina_Peter.pdf: 1012287 bytes, checksum: a6b5ae3184db955c29ee2d8a7adfa70f (MD5) Previous issue date: 2015-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / O objetivo deste estudo foi avaliar a atividade antimicrobiana (antibacteriana, antifúngica e antiviral), toxicidade celular e composição química de extratos hidroalcoólicos da própolis marrom (PM), verde (PV) e de abelhas nativas jataí (PJ). A atividade antibacteriana da própolis foi analisada pelo método de Microdiluição frente à Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus agalactiae e Escherichia coli. Para a atividade antifúngica, foi utilizada metodologia semelhante, frente à Candida lipolytica, Candida parapsilosis, Sporothrix schenckii e Sporothrix brasiliensis. A atividade antiviral foi avaliada através de dois métodos distintos de tratamento das células com os extratos: antes e depois da inoculação viral, frente ao Herpes Vírus Bovino (BoHV-1) e ao Vírus da Diarreia Viral Bovina (BVDV) e quantificado pelo teste de MTT (3-(4,5 dimetiltiazol-2yl)- 2-5-difenil-2H tetrazolato de bromo) e a atividade virucida, avaliada através de diferentes diluições dos vírus, temperaturas e tempos de incubações e analisadas por observação microscópica e quantificadas através da Dose Infectante (D.I.) 50%. A toxicidade foi avaliada através de diferentes concentrações e a viabilidade celular quantificada por MTT. À composição química das própolis foi determinada por Cromatografia Líquida de Alta Eficiência (CLAE). Os resultados da atividade antibacteriana demonstraram que PM obteve valores menores de Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM), quando testados frente à S. aureus (6,7 mg/mL; 13,4 mg/mL, respectivamente), e E. coli (29,4 mg/mL; 54,3 mg/mL) quando comparados ao PV e PJ. Contudo frente Streptococcus sp., os menores valores de CIM e CBM encontrados foram da PV (p<0,01). Na atividade antifúngica as PM, PV e PJ apresentaram eficácia à Candida sp. eSporotrix sp. A PJ apresentou menor toxicidade, em sequência PV e PM. Na atividade antiviral, os extratos foram mais eficazes quando acrescentados no pré-tratamento e a PM e PV foram mais eficazes ao BoHV-1, enquanto a PJ ao BVDV. Na virucida, a PVa 37°C obteve valores diferentes e menores (log = 2,67) em relação a PM (log = 3,5) e PJ (log = 3,76). No entanto, para BVDV a PJ apresentou os melhores resultados para ambas temperaturas. Os resultados demonstram o potencial da própolis como antimicrobiano no tratamento de doenças em Medicina Veterinária e Humana. / The objective of this study was to evaluate the antimicrobial activity (antibacterial, antifungal and antiviral), cell toxicity and chemical composition of hydroalcoholic extracts of brown propolis (PM), green (PV) and native bees jataí (PJ). The antibacterial activity of propolis was analyzed by microdilution method against the Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus agalactiae and Escherichia coli. For the antifungal activity, similar methodology was used, compared to Candida lipolytica, Candida parapsilosis, Sporothrix schenckii and Sporothrix brasiliensis. The antiviral activity was measured using two different methods of treatment of the cells with the extracts: before and after the viral inoculation against Bovine Herpes virus (bovine herpesvirus type 1) and Bovine Viral Diarrhea Virus (BVDV) and quantitated by assaying MTT (3- (4,5 dimethylthiazol-2yl) - 2,5-diphenyl-2H-tetrazolato bromine) and virucidal activity, measured using different dilutions of virus, temperatures and incubation times and analyzed by microscopic observation and quantified by the infective dose (ID) 50%. Toxicity was evaluated using different concentrations and cell viability measured by MTT. In the chemical composition of propolis was determined by High Performance Liquid Chromatography (HPLC) methods. The results demonstrated that the antibacterial activity had lower values PM Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) when tested against S. aureus (6.7 mg/mL; 13.4 mg/mL, respectively) and E. coli (29.4 mg/mL, 54.3 mg/mL) compared to the PV and PJ. However front Streptococcus sp., the lowest values of MIC and MBC were found of PV (p <0.01). In the antifungal activity PM, PV and PJ showed efficacy to Candida sp. and Sporotrix spp. The PJ showed lower toxicity in PV and PM sequence. In the antiviral activity, the extracts were more effective when added in the pre treatment and the PM and PV were more effective in BoHV-1, while the PJ to BVDV. In virucidal, PV obtained at 37°C and under different values (log = 2.67) compared to PM (log = 3.5) and PJ (log = 3.76). However, for BVDV PJ showed the best results for both temperatures. Results show the potential of propolis as an antimicrobial in the treatment of diseases in Veterinary Medicine and Human.

Plantas da família Guttiferae apresentam diversas atividades biológicas sendo Hypericum o gênero mais importante devido às atividades antidepressiva, antibacteriana e antiviral de algumas espécies. Hypericum connatum, utilizado no sul do Brasil para o tratamento de feridas de boca, demonstrou atividade contra o lentivírus, responsável pela imunodeficiência felina. Objetivo: isolar e identificar as substâncias majoritárias de H. connatum e testar a atividade de extratos obtidos das partes aéreas e raízes e das substâncias isoladas frente a duas cepas do herpesvírus simples tipo 1 (HSV-1). Método: foram obtidos frações nhexano, diclorometano e metanol e extratos bruto, aquosos a diferentes temperaturas e hidro-etanólico das partes aéreas e raízes. As frações n-hexano e metanólica das partes aéreas foram submetidas à coluna cromatográfica para o isolamento de substâncias. Os extratos e substâncias isoladas foram testados frente ao HSV-1, cepas KOS e ATCC-VR733. Determinou-se a concentração máxima não tóxica (CMNT) à célula e a concentração que provoca alteração morfológica em 50% das células (CC50) pela técnica da alteração morfológica celular, utilizando-se células VERO, linhagem ATCC CCL-81. A avaliação da atividade antiviral foi realizada em placas de microtitulação e medida pela inibição do efeito citopático (ECP) provocado pelo vírus. Resultados e Conclusões: da fração n-hexano foi isolado hiperbrasilol B, da fração metanólica foram isolados amentoflavona, hiperosídeo e guaijaveriana, além de um flavonol de estrutura ainda não definida (HCN3). A fração n-hexano e o extrato bruto das raízes inibiram o ECP das cepas KOS e ATCC-VR733. Os demais extratos testados não apresentaram atividade antiviral. Dentre as substâncias analisadas, hiperbrasilol B, amentoflavona e HCN3 foram ativos frente às duas cepas. Os flavonóides hiperosídeo e guaijaverina não apresentaram atividade anti-HSV-1. / Plants from Guttiferae family present many biological activities being Hypericum the most important genus due to the antidepressive, antiinflamatory and antimicrobial activities of some species. Hypericum connatum, used in south of Brazil for the treatment of mouth wounds, demonstrated activity against the feline immunodeficiency virus. Purpose: to isolate and identify the major compounds from H. connatum and to test extracts and compounds obtained from the roots and aerial parts against two strains of the herpes simplex virus type 1. Method: nhexane, dichloromethane and methanol fractions and aqueous and hydroethanolic from the aerial parts and roots were obtained. The n-hexane and methanolic fractions from the aerial parts were submitted to column chromatography. All extracts and isolated compounds were tested against the herpes simplex virus type 1, strains KOS and ATCC-VR733. The determination of The maximum non-toxic concentrations (CMNT) and the concentration that causes morphologic alterations in 50% of the cells (CC50) was carried out by the technique of cellular morphologic alterations, using VERO cells, strain ATCC CCL-81. The assay was performed in 96-well plates and the antiviral activity was evaluated by the inibition of the measured by the viral cytopathogenic effect assay (ECP). Results and Conclusions: hyperbrasilol B was isolated from the n-hexane fraction; amentoflavone, hyperoside, guaijaverin, and a flavonol not yet identified (HCN3) were isolated from methanolic fraction. The n-hexane fraction and the crude methanolic extracts were active against both strains tested. The other extracts tested did not display antiviral activity. Among the isolated compounds, hyperbrasilol B, amentoflavone and HCN3 were active against both strains. Hyperoside and guaijaverin were not active against HSV-1.

Plantas da família Guttiferae apresentam diversas atividades biológicas sendo Hypericum o gênero mais importante devido às atividades antidepressiva, antibacteriana e antiviral de algumas espécies. Hypericum connatum, utilizado no sul do Brasil para o tratamento de feridas de boca, demonstrou atividade contra o lentivírus, responsável pela imunodeficiência felina. Objetivo: isolar e identificar as substâncias majoritárias de H. connatum e testar a atividade de extratos obtidos das partes aéreas e raízes e das substâncias isoladas frente a duas cepas do herpesvírus simples tipo 1 (HSV-1). Método: foram obtidos frações nhexano, diclorometano e metanol e extratos bruto, aquosos a diferentes temperaturas e hidro-etanólico das partes aéreas e raízes. As frações n-hexano e metanólica das partes aéreas foram submetidas à coluna cromatográfica para o isolamento de substâncias. Os extratos e substâncias isoladas foram testados frente ao HSV-1, cepas KOS e ATCC-VR733. Determinou-se a concentração máxima não tóxica (CMNT) à célula e a concentração que provoca alteração morfológica em 50% das células (CC50) pela técnica da alteração morfológica celular, utilizando-se células VERO, linhagem ATCC CCL-81. A avaliação da atividade antiviral foi realizada em placas de microtitulação e medida pela inibição do efeito citopático (ECP) provocado pelo vírus. Resultados e Conclusões: da fração n-hexano foi isolado hiperbrasilol B, da fração metanólica foram isolados amentoflavona, hiperosídeo e guaijaveriana, além de um flavonol de estrutura ainda não definida (HCN3). A fração n-hexano e o extrato bruto das raízes inibiram o ECP das cepas KOS e ATCC-VR733. Os demais extratos testados não apresentaram atividade antiviral. Dentre as substâncias analisadas, hiperbrasilol B, amentoflavona e HCN3 foram ativos frente às duas cepas. Os flavonóides hiperosídeo e guaijaverina não apresentaram atividade anti-HSV-1. / Plants from Guttiferae family present many biological activities being Hypericum the most important genus due to the antidepressive, antiinflamatory and antimicrobial activities of some species. Hypericum connatum, used in south of Brazil for the treatment of mouth wounds, demonstrated activity against the feline immunodeficiency virus. Purpose: to isolate and identify the major compounds from H. connatum and to test extracts and compounds obtained from the roots and aerial parts against two strains of the herpes simplex virus type 1. Method: nhexane, dichloromethane and methanol fractions and aqueous and hydroethanolic from the aerial parts and roots were obtained. The n-hexane and methanolic fractions from the aerial parts were submitted to column chromatography. All extracts and isolated compounds were tested against the herpes simplex virus type 1, strains KOS and ATCC-VR733. The determination of The maximum non-toxic concentrations (CMNT) and the concentration that causes morphologic alterations in 50% of the cells (CC50) was carried out by the technique of cellular morphologic alterations, using VERO cells, strain ATCC CCL-81. The assay was performed in 96-well plates and the antiviral activity was evaluated by the inibition of the measured by the viral cytopathogenic effect assay (ECP). Results and Conclusions: hyperbrasilol B was isolated from the n-hexane fraction; amentoflavone, hyperoside, guaijaverin, and a flavonol not yet identified (HCN3) were isolated from methanolic fraction. The n-hexane fraction and the crude methanolic extracts were active against both strains tested. The other extracts tested did not display antiviral activity. Among the isolated compounds, hyperbrasilol B, amentoflavone and HCN3 were active against both strains. Hyperoside and guaijaverin were not active against HSV-1.

Plantas da família Guttiferae apresentam diversas atividades biológicas sendo Hypericum o gênero mais importante devido às atividades antidepressiva, antibacteriana e antiviral de algumas espécies. Hypericum connatum, utilizado no sul do Brasil para o tratamento de feridas de boca, demonstrou atividade contra o lentivírus, responsável pela imunodeficiência felina. Objetivo: isolar e identificar as substâncias majoritárias de H. connatum e testar a atividade de extratos obtidos das partes aéreas e raízes e das substâncias isoladas frente a duas cepas do herpesvírus simples tipo 1 (HSV-1). Método: foram obtidos frações nhexano, diclorometano e metanol e extratos bruto, aquosos a diferentes temperaturas e hidro-etanólico das partes aéreas e raízes. As frações n-hexano e metanólica das partes aéreas foram submetidas à coluna cromatográfica para o isolamento de substâncias. Os extratos e substâncias isoladas foram testados frente ao HSV-1, cepas KOS e ATCC-VR733. Determinou-se a concentração máxima não tóxica (CMNT) à célula e a concentração que provoca alteração morfológica em 50% das células (CC50) pela técnica da alteração morfológica celular, utilizando-se células VERO, linhagem ATCC CCL-81. A avaliação da atividade antiviral foi realizada em placas de microtitulação e medida pela inibição do efeito citopático (ECP) provocado pelo vírus. Resultados e Conclusões: da fração n-hexano foi isolado hiperbrasilol B, da fração metanólica foram isolados amentoflavona, hiperosídeo e guaijaveriana, além de um flavonol de estrutura ainda não definida (HCN3). A fração n-hexano e o extrato bruto das raízes inibiram o ECP das cepas KOS e ATCC-VR733. Os demais extratos testados não apresentaram atividade antiviral. Dentre as substâncias analisadas, hiperbrasilol B, amentoflavona e HCN3 foram ativos frente às duas cepas. Os flavonóides hiperosídeo e guaijaverina não apresentaram atividade anti-HSV-1. / Plants from Guttiferae family present many biological activities being Hypericum the most important genus due to the antidepressive, antiinflamatory and antimicrobial activities of some species. Hypericum connatum, used in south of Brazil for the treatment of mouth wounds, demonstrated activity against the feline immunodeficiency virus. Purpose: to isolate and identify the major compounds from H. connatum and to test extracts and compounds obtained from the roots and aerial parts against two strains of the herpes simplex virus type 1. Method: nhexane, dichloromethane and methanol fractions and aqueous and hydroethanolic from the aerial parts and roots were obtained. The n-hexane and methanolic fractions from the aerial parts were submitted to column chromatography. All extracts and isolated compounds were tested against the herpes simplex virus type 1, strains KOS and ATCC-VR733. The determination of The maximum non-toxic concentrations (CMNT) and the concentration that causes morphologic alterations in 50% of the cells (CC50) was carried out by the technique of cellular morphologic alterations, using VERO cells, strain ATCC CCL-81. The assay was performed in 96-well plates and the antiviral activity was evaluated by the inibition of the measured by the viral cytopathogenic effect assay (ECP). Results and Conclusions: hyperbrasilol B was isolated from the n-hexane fraction; amentoflavone, hyperoside, guaijaverin, and a flavonol not yet identified (HCN3) were isolated from methanolic fraction. The n-hexane fraction and the crude methanolic extracts were active against both strains tested. The other extracts tested did not display antiviral activity. Among the isolated compounds, hyperbrasilol B, amentoflavone and HCN3 were active against both strains. Hyperoside and guaijaverin were not active against HSV-1.

Peptídeos antimicrobianos (AMP) são importantes componentes do sistema imune de todos os organismos vivos. No plasma de Acanthoscurria rondoniae isolamos 15 AMP com similaridade com a hemocianina. As sete subunidades da hemocianina foram sequenciadas e sua estrutura tridimensional determinada. A rondonina, processada a partir de uma enzima do plasma em condições ácidas apresentou melhor atividade em pH ácido, sinergismo com gomesina, não citotóxico, não interagiu com membranas artificiais lipídicas, protegeu as células da infecção por vírus humanos de RNA e seu mecanismo de ação em leveduras está associado com material genético. Nossos resultados nos ajudam a entender porque aracnídeos sobreviveram por um longo tempo na escala evolutiva. E como as doenças infecciosas estão entre as principais causas de morte da população humana torna-se vital investir na busca de substâncias naturais ou sintéticas que exibam atividades antimicrobianas específicas e, acima de tudo, que as exerçam através de mecanismos de ação alternativos daqueles dos antibióticos disponíveis. / Antimicrobial peptides (AMP) are important components of the immune system of all living organisms. In the plasma of Acanthoscurria rondoniae we isolated 15 AMP with similarity to hemocyanin. The seven subunits hemocyanin were sequenced and determined its three-dimensional structure. The rondonin, processed from a plasma enzyme under acidic conditions showed best activity at acid pH, synergism with gomesin, non-cytotoxic, does not interacted with lipid artificial membrane, protected the cells from infection by human virus RNA and its mechanism of action in yeast is associated with genetic material. Our results help us understand why arachnids have survived for a long time on the evolutionary scale. And how infectious diseases are among the leading causes of death in human population becomes vital to invest in the search for natural or synthetic substances that exhibit specific antimicrobial activities and, above all, that engage through alternative mechanisms of action of these antibiotics available.

No description available.