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1.
bioRxiv ; 2023 Oct 24.
Article in English | MEDLINE | ID: mdl-37961153

ABSTRACT

The global incidence of chikungunya has surged in recent decades, with South America, particularly Brazil, experiencing devastating outbreaks. The primary vector for transmitting CHIKV in urban areas is the mosquito species Aedes aegypti, which is very abundant in Brazil. However, little is known about the impact of locally circulating CHIKV genotypes and specific combinations of mosquito populations on vector competence. In this study, we analyzed and compared the infectivity and transmissibility of a recently isolated CHIKV-ECSA lineage from Brazil among four Ae. aegypti populations collected from different regions of the country. When exposed to CHIKV-infected mice for blood feeding, all mosquito populations showed high infection rates and dissemination efficiency. Moreover, using a mouse model to assess transmission rates in a manner that better mirrors natural cycles, we observed that these populations exhibit highly efficient transmission rates of CHIKV-ECSA. Our findings underscore the robust capability of Brazilian Ae. aegypti populations to transmit the locally circulating CHIKV-ECSA lineage, potentially explaining its higher prevalence compared to the Asian lineage also introduced in Brazil.

2.
Toxicon ; 216: 50-56, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35787893

ABSTRACT

Diagnostic tests for brown spider accidents are unavailable and impact treatment decisions, increasing costs and patient risks. In this work, we used for the first time a fast, simple, and visual method based on the loop-mediated isothermal amplification assay (LAMP) to detect Loxosceles envenomation. Using the DNA from L. similis legs, we observed a high sensitivity using this test since as low as 0.32 pg of DNA could be detected. This pH-dependent colorimetric assay was 64 times more sensitive than PCR to detect spider DNA. The test was specific for Loxosceles once no cross-reaction was observed when testing DNA from different agents that cause similar dermonecrotic injuries. The test allowed the detection of Loxosceles intermedia DNA from hair, serum, and exudate samples obtained from experimentally-envenomed rabbit within 72 h. The method sensitivity varied according to the sample and the collection time, reaching 100% sensitivity in serum and hair, respectively, 1 h and 24 h after the experimental envenomation. Due to its ease of execution, speed, sensitivity, and specificity, LAMP presents an excellent potential for identifying Loxosceles spp. Envenomation. This can reduce the burden on the Health System and the morbidity for the patient by implementing the appropriate therapy immediately.In addition, this work opens up the perspective to other venomous animal accident identification using LAMP.


Subject(s)
Spider Venoms , Spiders , Animals , Colorimetry , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Phosphoric Diester Hydrolases/genetics , Rabbits , Sensitivity and Specificity , Spider Venoms/genetics , Spider Venoms/toxicity , Spiders/genetics
3.
Sci Rep ; 11(1): 10039, 2021 05 11.
Article in English | MEDLINE | ID: mdl-33976301

ABSTRACT

Field release of Wolbachia-infected Aedes aegypti has emerged as a promising solution to manage the transmission of dengue, Zika and chikungunya in endemic areas across the globe. Through an efficient self-dispersing mechanism, and the ability to induce virus-blocking properties, Wolbachia offers an unmatched potential to gradually modify wild Ae. aegypti populations turning them unsuitable disease vectors. Here we describe a proof-of-concept field trial carried out in a small community of Niterói, greater Rio de Janeiro, Brazil. Following the release of Wolbachia-infected eggs, we report here a successful invasion and long-term establishment of the bacterium across the territory, as denoted by stable high-infection indexes (> 80%). We have also demonstrated that refractoriness to dengue and Zika viruses, either thorough oral-feeding or intra-thoracic saliva challenging assays, was maintained over the adaptation to the natural environment of Southeastern Brazil. These findings further support Wolbachia's ability to invade local Ae. aegypti populations and impair disease transmission, and will pave the way for future epidemiological and economic impact assessments.


Subject(s)
Aedes/virology , Arboviruses/physiology , Mosquito Vectors/virology , Pest Control, Biological/statistics & numerical data , Wolbachia , Animals , Brazil , Dengue Virus/isolation & purification , Female , Pest Control, Biological/methods , Zika Virus/isolation & purification
4.
PLoS Negl Trop Dis ; 14(4): e0007518, 2020 04.
Article in English | MEDLINE | ID: mdl-32287269

ABSTRACT

Newly emerging or re-emerging arthropod-borne viruses (arboviruses) are important causes of human morbidity and mortality worldwide. Arboviruses such as Dengue (DENV), Zika (ZIKV), Chikungunya (CHIKV), and West Nile virus (WNV) have undergone extensive geographic expansion in the tropical and sub-tropical regions of the world. In the Americas the main vectors of DENV, ZIKV, and CHIKV are mosquito species adapted to urban environments, namely Aedes aegypti and Aedes albopictus, whereas the main vector of WNV is Culex quinquefasciatus. Given the widespread distribution in the Americas and high permissiveness to arbovirus infection, these mosquito species may play a key role in the epidemiology of other arboviruses normally associated with sylvatic vectors. Here, we test this hypothesis by determining the vector competence of Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus to Mayaro (MAYV) virus, a sylvatic arbovirus transmitted mainly by Haemagogus janthinomys that has been causing an increasing number of outbreaks in South America, namely in Brazil. Using field mosquitoes from Brazil, female mosquitoes were experimentally infected, and their competence for infection and transmission rates of MAYV was evaluated. We found consistent infection rate for MAYV in Ae. aegypti (57.5%) and Ae. albopictus (61.6%), whereas very low rates were obtained for Cx. quinquefasciatus (2.5%). Concordantly, we observed high potential transmission ability in Ae. aegypti and Ae. albopictus (69.5% and 71.1% respectively), in contrast to Cx. quinquefasciatus, which could not transmit the MAYV. Notably, we found that very low quantities of virus present in the saliva (undetectable by RT-qPCR) were sufficiently virulent to guarantee transmission. Although Ae. aegypti and Ae. albopictus mosquitoes are not the main vectors for MAYV, our studies suggest that these mosquitoes could play a significant role in the transmission of this arbovirus, since both species showed significant vector competence for MAYV (Genotype D), under laboratory conditions.


Subject(s)
Aedes/virology , Alphavirus Infections/virology , Alphavirus/isolation & purification , Culex/virology , Disease Transmission, Infectious , Alphavirus/genetics , Alphavirus/growth & development , Alphavirus Infections/transmission , Animals , Brazil , Female , Real-Time Polymerase Chain Reaction , Saliva/virology , Viral Load
5.
Gates Open Res ; 3: 161, 2019.
Article in English | MEDLINE | ID: mdl-31259313

ABSTRACT

Background: Yellow fever outbreaks have re-emerged in Brazil during 2016-18, with mortality rates up to 30%. Although urban transmission has not been reported since 1942, the risk of re-urbanization of yellow fever is significant, as Aedes aegypti is present in most tropical and sub-tropical cities in the World and still remains the main vector of urban YFV. Although the YFV vaccine is safe and effective, it does not always reach populations at greatest risk of infection and there is an acknowledged global shortage of vaccine supply. The introgression of Wolbachia bacteria into Ae. aegypti mosquito populations is being trialed in several countries ( www.worldmosquito.org) as a biocontrol method against dengue, Zika and chikungunya. Here, we studied the ability of Wolbachia to reduce the transmission potential of Ae. aegypti mosquitoes for Yellow fever virus (YFV). Methods: Two recently isolated YFV (primate and human) were used to challenge field-derived wild-type and Wolbachia-infected ( wMel +) Ae. aegypti mosquitoes. The YFV infection status was followed for 7, 14 and 21 days post-oral feeding (dpf). The YFV transmission potential of mosquitoes was evaluated via nano-injection of saliva into uninfected mosquitoes or by inoculation in mice. Results: We found that Wolbachia was able to significantly reduce the prevalence of mosquitoes with YFV infected heads and thoraces for both viral isolates. Furthermore, analyses of mosquito saliva, through indirect injection into naïve mosquitoes or via interferon-deficient mouse model, indicated Wolbachia was associated with profound reduction in the YFV transmission potential of mosquitoes (14dpf). Conclusions: Our results suggest that Wolbachia introgression could be used as a complementary strategy for prevention of urban yellow fever transmission, along with the human vaccination program.

6.
Insects ; 10(5)2019 May 10.
Article in English | MEDLINE | ID: mdl-31083286

ABSTRACT

Brazil has experienced several arbovirus outbreaks in recent years, among which yellow fever stands out. The state of Minas Gerais faced outbreaks of sylvatic yellow fever in 2017 and 2018, with 1002 confirmed cases and 340 deaths. This work presents the results of survey efforts to detect the yellow fever virus in mosquitoes from two conservation areas in the metropolitan region of Belo Horizonte, Brazil. A total of 867 mosquitoes of 20 species were collected between September 2017 and May 2018, the most abundant being Psorophora (Janthinosoma) ferox (von Humboldt, 1819) (31.3%), Limatus durhamii Theobald, 1901 (19.1%) and Haemagogus (Haemagogus) janthinomys Dyar, 1921 (18.2%). Total RNA was extracted from the mosquitoes for real-time PCR analysis for yellow fever, chikungunya, mayaro, Zika and dengue viruses. The yellow fever infection rate was 8.2% for Hg. janthinomys (13 mosquitoes), which is the main vector of sylvatic yellow fever in Brazil. In addition to surveying the mosquito fauna of these conservation units, this work demonstrates the importance of monitoring the circulation of viruses near large urban centers.

7.
Parasit Vectors ; 12(1): 33, 2019 Jan 15.
Article in English | MEDLINE | ID: mdl-30646951

ABSTRACT

BACKGROUND: The leishmaniases are important neglected diseases caused by Leishmania spp. which are transmitted by sand flies, Lutzomyia longipalpis being the main vector of visceral leishmaniasis in the Americas. The methodologies for leishmaniasis control are not efficient, causing 1.5 million reported cases annually worldwide, therefore showing the need for development of novel strategies and interventions to control transmission of the disease. The bacterium Wolbachia pipientis is being used to control viruses transmitted by mosquitoes, such as dengue and Zika, and its introduction in disease vectors has been effective against parasites such as Plasmodium. Here we show the first successful establishment of Wolbachia into two different embryonic cell lines from L. longipalpis, LL-5 and Lulo, and analysed its effects on the sand fly innate immune system, followed by in vitro Leishmania infantum interaction. RESULTS: Our results show that LL-5 cells respond to wMel and wMelPop-CLA strains within the first 72 h post-infection, through the expression of antimicrobial peptides and inducible nitric oxide synthase resulting in a decrease of Wolbachia detection in the early stages of infection. In subsequent passages, the wMel strain was not able to infect any of the sand fly cell lines while the wMelPop-CLA strain was able to stably infect Lulo cells and LL-5 at lower levels. In Wolbachia stably infected cells, the expression of immune-related genes involved with downregulation of the IMD, Toll and Jak-Stat innate immune pathways was significantly decreased, in comparison with the uninfected control, suggesting immune activation upon Wolbachia transinfection. Furthermore, Wolbachia transinfection did not promote a negative effect on parasite load in those cells. CONCLUSIONS: Initial strong immune responses of LL5 cells might explain the inefficiency of stable infections in these cells while we found that Lulo cells are more permissive to infection with Wolbachia causing an effect on the cell immune system, but not against in vitro L. infantum interaction. This establishes Lulo cells as a good system for the adaptation of Wolbachia in L. longipalpis.


Subject(s)
Gene Expression , Immunity, Innate , Immunologic Factors/biosynthesis , Leishmania infantum/growth & development , Microbial Interactions , Psychodidae/immunology , Wolbachia/immunology , Animals , Cell Line , Parasite Load , Psychodidae/microbiology , Wolbachia/growth & development
8.
Sci Rep ; 8(1): 6889, 2018 05 02.
Article in English | MEDLINE | ID: mdl-29720714

ABSTRACT

Wolbachia, an intracellular endosymbiont present in up to 70% of all insect species, has been suggested as a sustainable strategy for the control of arboviruses such as Dengue, Zika and Chikungunya. As Mayaro virus outbreaks have also been reported in Latin American countries, the objective of this study was to evaluate the vector competence of Brazilian field-collected Ae. aegypti and the impact of Wolbachia (wMel strain) upon this virus. Our in vitro studies with Aag2 cells showed that Mayaro virus can rapidly multiply, whereas in wMel-infected Aag2 cells, viral growth was significantly impaired. In addition, C6/36 cells seem to have alterations when infected by Mayaro virus. In vivo experiments showed that field-collected Ae. aegypti mosquitoes are highly permissive to Mayaro virus infection, and high viral prevalence was observed in the saliva. On the other hand, Wolbachia-harboring mosquitoes showed significantly impaired capability to transmit Mayaro virus. Our results suggest that the use of Wolbachia-harboring mosquitoes may represent an effective mechanism for the reduction of Mayaro virus transmission throughout Latin America.


Subject(s)
Aedes/virology , Mosquito Vectors/virology , Togaviridae/physiology , Virus Replication , Wolbachia/pathogenicity , Aedes/microbiology , Animals , Cell Line , Cells, Cultured , Female , Humans , Mosquito Vectors/microbiology , Symbiosis , Togaviridae/pathogenicity , Togaviridae Infections/transmission
9.
Cell Host Microbe ; 19(6): 771-4, 2016 Jun 08.
Article in English | MEDLINE | ID: mdl-27156023

ABSTRACT

The recent association of Zika virus with cases of microcephaly has sparked a global health crisis and highlighted the need for mechanisms to combat the Zika vector, Aedes aegypti mosquitoes. Wolbachia pipientis, a bacterial endosymbiont of insect, has recently garnered attention as a mechanism for arbovirus control. Here we report that Aedes aegypti harboring Wolbachia are highly resistant to infection with two currently circulating Zika virus isolates from the recent Brazilian epidemic. Wolbachia-harboring mosquitoes displayed lower viral prevalence and intensity and decreased disseminated infection and, critically, did not carry infectious virus in the saliva, suggesting that viral transmission was blocked. Our data indicate that the use of Wolbachia-harboring mosquitoes could represent an effective mechanism to reduce Zika virus transmission and should be included as part of Zika control strategies.


Subject(s)
Aedes/microbiology , Aedes/virology , Wolbachia/physiology , Zika Virus/physiology , Animals , Antibiosis , Brazil , Disease Transmission, Infectious/prevention & control , Female , Insect Vectors/microbiology , Insect Vectors/virology , Male , Saliva/microbiology , Saliva/virology , Symbiosis , Zika Virus/isolation & purification , Zika Virus Infection/microbiology , Zika Virus Infection/prevention & control , Zika Virus Infection/transmission , Zika Virus Infection/virology
10.
Bioinorg Chem Appl ; 2013: 961783, 2013.
Article in English | MEDLINE | ID: mdl-23781165

ABSTRACT

Leishmania amazonensis is the etiologic agent of the cutaneous and diffuse leishmaniasis often associated with drug resistance. Lapachol [2-hydroxy-3-(3'-methyl-2-butenyl)-1,4-naphthoquinone] displays a wide range of antimicrobial properties against many pathogens. In this study, using the classic microscopic in vitro model, we have analyzed the effects of a series of lapachol and chlorides complexes with antimony (V), bismuth (V), and tin (IV) against L. amazonensis. All seven compounds exhibited antileishmanial activity, but most of the antimony (V) and bismuth (V) complexes were toxic against human HepG2 cells and murine macrophages. The best IC50 values (0.17 ± 0.03 and 0.10 ± 0.11 µg/mL) were observed for Tin (IV) complexes (3) [(Lp)(Ph3Sn)] and (6) (Ph3SnCl2), respectively. Their selective indexes (SIs) were 70.65 and 120.35 for HepG2 cells, respectively. However, while analyzing murine macrophages, the SI decreased. Those compounds were moderately toxic for HepG2 cells and toxic for murine macrophages, still underlying the need of chemical modification in this class of compounds.

11.
Belo Horizonte; s.n; 2013. 104 p. ilus.
Thesis in Portuguese | LILACS, Coleciona SUS | ID: biblio-938797

ABSTRACT

As Leishmanioses são doenças negligenciadas. O tratamento dos pacientes é a principal medida de controle, porém a quimioterapia das Leishmanioses apresenta dificuldades incluindo: toxicidade dos medicamentos disponíveis, via de administração parenteral e resistência natural de algumas cepas. O método de teste de drogas clássico in vitro baseado na contgem microscópica de macrófagos infectados apresenta limitações por ser laborioso, não automatizado e sujeito a variações do observador. Deste modo, a busca por novos métodos de triagem de drogas faz-se necessário. O estabelecimento de métodos semi-automatizados contribuiria para aumentar a eficiência da busca de novas drogas contra Leishmania. Neste trabalho, a cepa de Leishmania amazonensis (PH8) foi transfectada com a proteína vermelha fluorescente (RFP). Os parasitos transfectados foram avaliados segundo parâmetros celulares e de susceptibilidade aos fármacos leishmanicidas tradicionais e derivados do propranolol. Os parasitos selvagens (WT) e transfectados (RFP) foram analisados pela Citometria de Fluxo e Microscopia de Fluorescência sendo facilmente discriminados por estas técnicas. Em geral,não foram observadas diferenças na susceptibilidade entre as cepas WT e RFP frente às moléculas testadas.


Os parasitos RFPs foram submetidos ao teste de drogas com posterior leitura no fluorímetro para a padronização do método fluorimétrico. O método fluorimétrico se mostrou bastante reprodutível em relação ao método clássico. Entretanto, durante a padronização do método, mudanças na concentração das drogas foram necessárias bem como a determinação de um ponto de corte nos valores de IC50. Este trabalho também avaliou a atividade leishmanicida dos derivados das poliaminas e complexos metálicos de lapachol utilizando-se o método clássico. Não só os derivados do propranolol, mas também os das poliaminas e lapachol se mostraram tóxicos para células de Hepatoma humano (HepG2). Este trabalho possibilitou pela primeira vez a utilização de parasitos RFPs como modelo de um teste de drogas semi-automatizado


Subject(s)
Male , Female , Humans , Animals , Guinea Pigs , Mice , Fluorometry/methods , Leishmania/parasitology , Leishmaniasis/drug therapy , Transfection/instrumentation
12.
Belo Horizonte; s.n; 2013. 104 p. ilus.
Thesis in Portuguese | LILACS | ID: lil-683933

ABSTRACT

As Leishmanioses são doenças negligenciadas. O tratamento dos pacientes é a principal medida de controle, porém a quimioterapia das Leishmanioses apresenta dificuldades incluindo: toxicidade dos medicamentos disponíveis, via de administração parenteral e resistência natural de algumas cepas. O método de teste de drogas clássico in vitro baseado na contgem microscópica de macrófagos infectados apresenta limitações por ser laborioso, não automatizado e sujeito a variações do observador. Deste modo, a busca por novos métodos de triagem de drogas faz-se necessário. O estabelecimento de métodos semi-automatizados contribuiria para aumentar a eficiência da busca de novas drogas contra Leishmania. Neste trabalho, a cepa de Leishmania amazonensis (PH8) foi transfectada com a proteína vermelha fluorescente (RFP). Os parasitos transfectados foram avaliados segundo parâmetros celulares e de susceptibilidade aos fármacos leishmanicidas tradicionais e derivados do propranolol. Os parasitos selvagens (WT) e transfectados (RFP) foram analisados pela Citometria de Fluxo e Microscopia de Fluorescência sendo facilmente discriminados por estas técnicas. Em geral,não foram observadas diferenças na susceptibilidade entre as cepas WT e RFP frente às moléculas testadas. Os parasitos RFPs foram submetidos ao teste de drogas com posterior leitura no fluorímetro para a padronização do método fluorimétrico. O método fluorimétrico se mostrou bastante reprodutível em relação ao método clássico. Entretanto, durante a padronização do método, mudanças na concentração das drogas foram necessárias bem como a determinação de um ponto de corte nos valores de IC50. Este trabalho também avaliou a atividade leishmanicida dos derivados das poliaminas e complexos metálicos de lapachol utilizando-se o método clássico. Não só os derivados do propranolol, mas também os das poliaminas e lapachol se mostraram tóxicos para células de Hepatoma humano (HepG2). Este trabalho possibilitou pela primeira vez a utilização de parasitos RFPs como modelo de um teste de drogas semi-automatizado.


Subject(s)
Humans , Animals , Male , Female , Guinea Pigs , Mice , Fluorometry/methods , Leishmania/parasitology , Leishmaniasis/drug therapy , Transfection/instrumentation
13.
J Trop Med ; 2012: 429586, 2012.
Article in English | MEDLINE | ID: mdl-22991521

ABSTRACT

Background. Leishmaniases are diseases with a wide spectrum of clinical manifestations including cutaneous (CL) and visceral (VL) forms. Many factors may affect their occurrence and expansion including environmental, geographic, and social conditions. In the past two decades, Divinópolis, Minas Gerais State, Brazil, has exhibited the potential for a disease outbreak, with the appearance of CL, and VL cases (human and canine). Hence, this study was initiated to monitor public knowledge of the disease. Questionnaires were administered in four neighborhoods (Jardim Belvedere, Esplanada, Danilo Passos I and II) where most of the human and canine cases have been reported. The analyses demonstrated that public knowledge of the disease is sparse and fragmented. A strong perception of the dog as the main reservoir was observed. Five veterinary clinics were evaluated for the presence of canine VL using serological (RIFI and ELISA) and molecular (PCR-RFLP) techniques. This is the first study demonstrating the occurrence of Leishmania infantum in Divinópolis, suggesting a possible urbanization of VL.

14.
Diagn Microbiol Infect Dis ; 68(4): 401-9, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20926219

ABSTRACT

Leishmaniasis is a disease caused by the protozoan Leishmania resulting in a variety of clinical manifestations, from self-healing skin lesions to fatal visceral disease. The development of polymerase chain reaction (PCR)-based techniques has made species identification easier, faster, and less labor intensive. The main targets for PCR amplification include kinetoplastid DNA (kDNA), miniexon, and conserved regions such as the internal transcribed spacer. The objective of this work was to evaluate 4 different PCR techniques designed to type Leishmania using laboratory strains. Parasites were subjected to 4 PCR procedures using specific Leishmania primers for miniexon (designated A1 and A2) and kDNA (designated B1 and B2, C1 and C2, and D1, D2 and D3). Discrimination between some species and the 2 main subgenera Leishmania and Viannia was achieved. Unweighted pair group method analysis resulted in the expected clustering of the 2 species from the subgenus Leishmania. However, some species in the subgenus Viannia could not be distinguished, representing a continued challenge for PCR-based protocols. Results are discussed in terms of advantages, limitations, and reproducibility of these 4 PCR-based techniques in the taxonomy of Leishmania.


Subject(s)
Leishmania/classification , Leishmaniasis/diagnosis , Leishmaniasis/parasitology , Polymerase Chain Reaction/methods , Animals , Culture Media , DNA Primers , DNA, Kinetoplast/analysis , DNA, Kinetoplast/isolation & purification , DNA, Protozoan/analysis , DNA, Protozoan/isolation & purification , DNA, Ribosomal Spacer/analysis , Exons/genetics , Humans , Leishmania/genetics , Leishmania/isolation & purification , Polymorphism, Restriction Fragment Length , Reproducibility of Results , Sensitivity and Specificity , Species Specificity
15.
Belo Horizonte; s.n; 2009. 83 p. ilus.
Thesis in Portuguese | LILACS | ID: lil-658707

ABSTRACT

As Leishmanioses estão entre as doenças tropicais mais importantes classificadas pela Organização Mundial de Saúde como doenças negligenciadas. Seu controle é baseado no tratamento de casos humanos, borrifação com inseticidas e eliminação dos reservatórios quando possível. Entretanto, a quimioterapia das Leishmanioses apresenta algumas dificuldades tais como: toxicidade dos medicamentos disponíveis, via de administração e resistência natural de algumas cepas. O método de teste de drogas tradicional in vitro apresenta limitações por ser laborioso e sujeito a variações individuais do observador. Devido a estes obstáculos a procura de novas drogas e desenvolvimento de métodos faz-se necessária . Por isso é importante o estabelecimento de um método semi-automatizado para teste de drogas em Leishmania. Para que isto seja alcançado utilizou-se de técnicas de biologia molecular como a inserção de um fenótipo no protozoário permitindo sua detecção em um aparelho. Neste trabalho, produzimos cepas de Leishmania expressando a proteína verde fluorescente (“green fluorescent protein”- GFP). Essa proteína foi transfectada nas espécies brasileiras de maior importância médica: L. chagasi, L. braziliensis, L. amazonensis e L guyanensis. Para confirmar a tranfecção, os parasitos selvagens (WT) e transformados (GFPs)foram analisados pela Citometria de Fluxo (FACS) e Microscopia Laser Confocal (LCM)


Para avaliar se a transfecção teve algum impacto na viabilidade celular de L. amazonensis foram realizados alguns ensaios biológicos como a comparação da curva de crescimento e infectividade em macrófagos entre as cepas selvagem e GFP. Posteriormente foi verificada a susceptibilidade à drogas. L. amazonensis foram expostas aos fármacos tradicionais e moléculas teste e os valores de IC50 determinados. Não foram observadas diferenças na susceptibilidade entre as cepas tanto na presença dos fármacos tradicionais (Anfotericina B e Glucantime), como de moléculas teste (derivadas do propranolol). Baseado nos valores de IC50 obtidos com o teste tradicional a transformação da cepa GFP de L. amazonensis não alterou suas características biológicas nem de susceptilibidade aos agentes leishmanicidas tradicionais e moléculas teste. Algumas moléculas derivadas do propranolol mostraram ser promissoras na atividade leishmanicida. Estes resultados dão suporte à utilização da cepa GFP nos testes semi-automatizados utilizando o fluorímetro. Isso possibilitará o teste de um número maior de fármacos/moléculas aumentando a eficiência do método quimioterápico atual


Subject(s)
Humans , Animals , Male , Female , Cattle , Dogs , Guinea Pigs , Mice , Fluorometry , Fluorescent Antibody Technique/methods , Leishmaniasis/drug therapy , Transfection/instrumentation
16.
Belo Horizonte; s.n; 2009. 83 p. ilus.
Thesis in Portuguese | LILACS, Coleciona SUS | ID: biblio-937861

ABSTRACT

As Leishmanioses estão entre as doenças tropicais mais importantes classificadas pela Organização Mundial de Saúde como doenças negligenciadas. Seu controle é baseado no tratamento de casos humanos, borrifação com inseticidas e eliminação dos reservatórios quando possível. Entretanto, a quimioterapia das Leishmanioses apresenta algumas dificuldades tais como: toxicidade dos medicamentos disponíveis, via de administração e resistência natural de algumas cepas. O método de teste de drogas tradicional in vitro apresenta limitações por ser laborioso e sujeito a variações individuais do observador. Devido a estes obstáculos a procura de novas drogas e desenvolvimento de métodos faz-se necessária . Por isso é importante o estabelecimento de um método semi-automatizado para teste de drogas em Leishmania. Para que isto seja alcançado utilizou-se de técnicas de biologia molecular como a inserção de um fenótipo no protozoário permitindo sua detecção em um aparelho. Neste trabalho, produzimos cepas de Leishmania expressando a proteína verde fluorescente (“green fluorescent protein”- GFP). Essa proteína foi transfectada nas espécies brasileiras de maior importância médica: L. chagasi, L. braziliensis, L. amazonensis e L guyanensis. Para confirmar a tranfecção, os parasitos selvagens (WT) e transformados (GFPs)foram analisados pela Citometria de Fluxo (FACS) e Microscopia Laser Confocal (LCM)


Para avaliar se a transfecção teve algum impacto na viabilidade celular de L. amazonensis foram realizados alguns ensaios biológicos como a comparação da curva de crescimento e infectividade em macrófagos entre as cepas selvagem e GFP. Posteriormente foi verificada a susceptibilidade à drogas. L. amazonensis foram expostas aos fármacos tradicionais e moléculas teste e os valores de IC50 determinados. Não foram observadas diferenças na susceptibilidade entre as cepas tanto na presença dos fármacos tradicionais (Anfotericina B e Glucantime), como de moléculas teste (derivadas do propranolol). Baseado nos valores de IC50 obtidos com o teste tradicional a transformação da cepa GFP de L. amazonensis não alterou suas características biológicas nem de susceptilibidade aos agentes leishmanicidas tradicionais e moléculas teste. Algumas moléculas derivadas do propranolol mostraram ser promissoras na atividade leishmanicida. Estes resultados dão suporte à utilização da cepa GFP nos testes semi-automatizados utilizando o fluorímetro. Isso possibilitará o teste de um número maior de fármacos/moléculas aumentando a eficiência do método quimioterápico atual


Subject(s)
Male , Female , Humans , Animals , Cattle , Dogs , Guinea Pigs , Mice , Fluorescent Antibody Technique/methods , Fluorometry , Leishmaniasis/drug therapy , Transfection/instrumentation
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