Study of karyotype and constitutive heterochromatin of Mansonia spp. (Diptera: Culicidae) in the area surrounding the Jirau Hydroelectric Dam, Rondônia, Brazil

ABSTRACT Background: Mansonia mosquitoes transmit arboviruses to humans. This study describes the karyotypes and C-banding of Mansonia humeralis, Mansonia titillans, Mansonia pseudotitillans, and Mansonia indubitans. Methods: From the 202 larvae, the brain ganglia were dissected (n=120) for the preparation of slides. Twenty slides with well-distended chromosomes for each species (10 for karyotyping and 10 for C-banding) were selected for further study. Results: The haploid genome and the average lengths of the chromosomal arms differed in relation to the centromere between species, and intraspecific differences also occurred in the distribution of the C-bands. Conclusions: These results are useful for better understanding of the chromosomal variability of Mansonia mosquitoes.

Endophytic fungus Phomopsis sp. as a source of 3-nitropropionic acid with larvicidal activity against Aedes aegypti (Linnaeus 1762, Diptera: Culicidae)

ABSTRACT Background: Aedes aegypti is the primary vector of viruses, such as Zika, chikungunya, yellow fever, and dengue. In this context, a biomonitored chemical study was conducted to evaluate the activity of the crude extract of the endophytic fungus Phomopsis sp. against the larvae of Aedes aegypti. Methods: Crude extract, fractions, and isolated substances were evaluated in in-vitro assays against third-stage larvae of Aedes aegypti. Results: We isolated 3-nitropropionic acid with an LC50 of 15.172 ppm and LC90 of 18.178 ppm after 24 hours of larval exposure. Conclusions: The results indicated that 3-nitropropionic acid exerted larvicidal activity.

Histopathological evaluation of formalin toxicity in Arapaima gigas (Arapaimidae), the giant fish from Amazon / Avaliação histopatológica da toxicidade da formalina em Arapaima gigas (Arapaimidae), o peixe gigante da Amazônia

This study aimed to determine the lethal concentration and the structural and ultra-structural effects caused by the formalin exposure on juveniles of Arapaima gigas. Ninety fish (60.1± 2.5g and 20.2±0.9cm) were exposed to 0, 22, 44, 66, 88 and 110mg L-1 in order to determine the lethal concentration (LC50-96h) that was 36.4mg L-1 of formalin. Sublethal effects were evaluated using histopathological analysis on the gills and assessment of behavioral alterations and clinical signs. The LC50 of formalin for 24, 48 and 72h was 88.3, 64.7 and 56.8mg L-1 respectively. Clinical signs and behavioral changes were found: erratic swimming, lethargy, crowding on the water surface, loss of hydrodynamic equilibrium, spasms and agonistic confrontation, which were observed only at 88 and 110mg L-1. The histological alteration index (HAI) showed that 66, 88 and 100mg L-1 presented significant difference (p<0.05) in relation to unexposed fish, indicating that moderate damage to the gills of fish exposed to formalin had occurred. The mean values of alteration (MVA) for 22, 44, 66, 88 and 110mg L-1 were 1.14, 1.29, 1.51, 1.53 and 1.60 respectively, and differences in this index were only observed with 110 mgL-1 of formalin. It is therefore possible to conclude that sublethal concentrations of formalin (22.0mg L-1) did not compromise the health of juveniles of A. gigas. Finally, concentrations greater than to LC50-96h may be carefully used for short-term exposure, since the MVA for all concentrations tested only indicated localized lesions that did not compromise gills functionality of exposed fish.(AU)

O presente estudo teve como objetivo determinar a concentração letal e efeitos estruturais e ultraestruturais causados pela exposição a formalina em juvenis de Arapaima gigas. Noventa peixes (60,1±2,5g e 20,2±0,9cm) foram expostos a 0, 22, 44, 66, 88 e 110mg L-1, para determinar a concentração letal (CL50-96h) de formalina que foi 36,4mg L-1. Os efeitos subletais foram avaliados por análises histopatológicas das brânquias e avaliação das alterações comportamentais e sinais clínicos. A CL50 de formalina para 24, 48 e 72horas foi de 88,3, 64,7 e 56,8; respectivamente. Sinais clínicos e alterações comportamentais encontradas foram: natação errática, letargia, aglomeração de peixes na superfície da água, perda de equilíbrio hidrodinâmico, espasmos e confronto agonísticos, observados apenas nas concentrações de 88 e 110mg L-1. O índice de alteração histológica (IAH) mostrou que as concentrações de 66, 88 e 100mg L-1 apresentaram diferenças significativas (p<0,05) em relação aos controles, indicando a ocorrência de danos moderados nas brânquias dos peixes expostos a formalina. Os valores médios de alteração (VMA) para as concentrações 22, 44, 66, 88 e 110mg L-1 foram 1,14, 1,29, 1,51, 1,53 e 1,60; respectivamente, e as diferenças na composição desse índice foram observados apenas na exposição com 110mg L-1 de formalina. Foi possível concluir que concentrações subletais de formalina (22,0mg L-1) não comprometem a saúde de juvenis de A. gigas. Concentrações de formalina acima da CL50-96h podem ser usadas cuidadosamente para banho de curto tempo, uma vez que o VMA para todas as concentrações testadas indicou apenas lesões localizadas que não comprometem a funcionalidade das brânquias dos peixes expostos.(AU)

Production of thermostable ß-glucosidase and CMCase by Penicillium sp: LMI01 isolated from the Amazon region

Background: Cellulolytic enzymes of microbial origin have great industrial importance because of their wide application in various industrial sectors. Fungi are considered the most efficient producers of these enzymes. Bioprospecting survey to identify fungal sources of biomass-hydrolyzing enzymes from a high-diversity environment is an important approach to discover interesting strains for bioprocess uses. In this study, we evaluated the production of endoglucanase (CMCase) and ß-glucosidase, enzymes from the lignocellulolytic complex, produced by a native fungus. Penicillium sp. LMI01 was isolated from decaying plant material in the Amazon region, and its performance was compared with that of the standard isolate Trichoderma reesei QM9414 under submerged fermentation conditions. Results: The effectiveness of LMI01 was similar to that of QM9414 in volumetric enzyme activity (U/mL); however, the specific enzyme activity (U/mg) of the former was higher, corresponding to 24.170 U/mg of CMCase and 1.345 U/mg of ß-glucosidase. The enzymes produced by LMI01 had the following physicochemical properties: CMCase activity was optimal at pH 4.2 and the ß-glucosidase activity was optimal at pH 6.0. Both CMCase and ß-glucosidase had an optimum temperature at 60°C and were thermostable between 50 and 60°C. The electrophoretic profile of the proteins secreted by LMI01 indicated that this isolate produced at least two enzymes with CMCase activity, with approximate molecular masses of 50 and 35 kDa, and ß-glucosidases with molecular masses between 70 and 100 kDa. Conclusions: The effectiveness and characteristics of these enzymes indicate that LMI01 can be an alternative for the hydrolysis of lignocellulosic materials and should be tested in commercial formulations.

Composition and structure of the fig wasp community in Amazonia / Composição e estrutura da comunidade de vespas-de-figo na Amazônia

An understanding of the complex ecological interaction between fig wasps and their host plants in Amazonia requires previous knowledge of their distribution and diversity. The objective of this study was to describe the composition and structure of the wasp community associated with four species of Ficus in the municipal area of Manaus, Amazonas, Brazil. A total of 600 syconia from four species were collected. The study species were: Ficus obtusifolia Kunth; Ficus citrifolia Mill; F. americana subspecies guianensis Desv. form mathewsii; and F. americana subspecies guianensis Desv. form parkeriana. Statistical analyses were used to examine the relationship between fig wasp diversity and syconium diameter, and the effect of non-pollinating wasps on numbers of pollinators and seeds. Forty three species of fig wasp were identified, distributed across seven genera (Pegoscapus, Idarnes, Aepocerus, Physothorax, Anidarnes, Heterandrium , Eurytoma). Idarnes (carme group) was the wasps genus non-pollinator with greatest number of individuals with the greatest number of infested syconia (7409 wasps in 376 syconia). Analysing non-pollinating wasp diversity in relation to fig diameter, a significant difference was observed between the four fig species. Ficus citrifolia and F. americana subspecies guianensis form mathewsii had the smallest diameter but the greatest diversity of fig wasp. Ficus obtusifolia was the only species in which the non-pollinating wasps had a significant negative effect on the number of Pegoscapus sp. and on seed production.

A compreensão sobre as complexas interações ecológicas envolvendo vespas-de-figo e suas plantas hospedeiras na Amazônia depende do conhecimento prévio sobre a distribuição e diversidade dessas vespas. O objetivo deste estudo foi descrever a composição e estrutura da comunidade de vespas associadas a quatro espécies de Ficus no município de Manaus, Amazonas. Foram coletados e analisados 600 sicônios de quatro espécies: Ficus obtusifolia Kunth; Ficus citrifolia Mill; F. americana subspecies guianensis Desv. forma mathewsii; and F. americana subspecies guianensis Desv. forma parkeriana. Análises estatísticas foram usadas para analisar a relação entre a diversidade de vespas-de-figo e o diâmetro do sicônio, e o efeito das vespas não-polnizadoras em relação ao número de polinizadoras e sementes. Foram encontradas 43 espécies de vespas-de-figo distribuídas em sete gêneros (Pegoscapus, Idarnes, Aepocerus, Physothorax, Anidarnes, Heterandrium , Eurytoma). Idarnes grupo carme foi o gênero de vespas não-polinizadora com maior numero de individuos com maior numero de sicônios infestado (7.409 vespas em 376 sicônios). Ao analisar a diversidade de vespas não-polinizadoras em relação ao diâmetro do figo observou-se diferença significativa entre as quatro espécies de figueiras. Ficus citrifolia e F. americana, subespécie guianensis, forma mathewsii apresentaram o diâmetro menor, porém uma maior diversidade de vespas-de-figo. Ficus obtusifolia foi a única espécie em que as vespas não-polinizadoras exerceram efeito negativo significativo tanto no número de Pegoscapus sp. quanto na produção de sementes.

Mass trapping with MosquiTRAPs does not reduce Aedes aegypti abundance

The objective of this study was to evaluate the effectiveness of Aedes aegypti mass trapping using the sticky trap MosquiTRAP (MQT) by performing a cluster randomised controlled trial in Manaus, state of Amazonas, Brazil. After an initial questionnaire and baseline monitoring of adult Ae. aegypti abundance with BG-Sentinel (BGS) traps in six clusters, three clusters were randomly assigned to the intervention arm where each participating household received three MQTs for mass trapping during 17 months. The remaining three clusters (control arm) did not receive traps. The effect of mass trapping on adult Ae. aegypti abundance was monitored fortnightly with BGS traps. During the last two months of the study, a serological survey was conducted. After the study, a second questionnaire was applied in the intervention arm. Entomological monitoring indicated that MQT mass trapping did not reduce adult Ae. aegypti abundance. The serological survey indicated that recent dengue infections were equally frequent in the intervention and the control arm. Most participants responded positively to questions concerning user satisfaction. According to the results, there is no evidence that mass trapping with MQTs can be used as a part of dengue control programs. The use of this sticky trap is only recommendable for dengue vector monitoring.

Temporal abundance of Aedes aegypti in Manaus, Brazil, measured by two trap types for adult mosquitoes

A longitudinal study was conducted in Manaus, Brazil, to monitor changes of adult Aedes aegypti (L.) abundance. The objectives were to compare mosquito collections of two trap types, to characterise temporal changes of the mosquito population, to investigate the influence of meteorological variables on mosquito collections and to analyse the association between mosquito collections and dengue incidence. Mosquito monitoring was performed fortnightly using MosquiTRAPs (MQT) and BG-Sentinel (BGS) traps between December 2008-June 2010. The two traps revealed opposing temporal infestation patterns, with highest mosquito collections of MQTs during the dry season and highest collections of BGS during the rainy seasons. Several meteorological variables were significant predictors of mosquito collections in the BGS. The best predictor was the relative humidity, lagged two weeks (in a positive relationship). For MQT, only the number of rainy days in the previous week was significant (in a negative relationship). The correlation between monthly dengue incidence and mosquito abundance in BGS and MQT was moderately positive and negative, respectively. Catches of BGS traps reflected better the dynamic of dengue incidence. The findings help to understand the effects of meteorological variables on mosquito infestation indices of two different traps for adult dengue vectors in Manaus.

Identification of dengue viruses in naturally infected Aedes aegypti females captured with BioGents (BG)-Sentinel traps in Manaus, Amazonas, Brazil

Introduction In Manaus, the first autochthonous cases of dengue fever were registered in 1998. Since then, dengue cases were diagnosed by the isolation of viruses 1, 2, 3, and 4. Methods One hundred eighty-seven mosquitoes were collected with BioGents (BG)-Sentinel traps in 15 urban residential areas in the Northern Zone of Manaus and processed by molecular tests. Results Infections with dengue viruses 1, 2, 3, and 4 and a case of co-infection with dengue viruses 2 and 3 were identified. Conclusions These findings corroborate the detection of dengue in clinical samples and reinforce the need for epidemiological surveillance by the Health authorities. .

Occurrence of Aelurostrongylus abstrusus (Railliet, 1898) larvae (Nematoda: Metastrongylidae) infecting Achatina (Lissachatina) fulica Bowdich, 1822 (Mollusca: Gastropoda) in the Amazon region / Ocorrência de Aelurostrongylus abstrusus (Railliet, 1898) (Nematoda: Metastrongylidae) infectando o Achatina (Lissachatina) fulica Bowdich, 1822 (Mollusca: Gastropoda) na região amazônica

Achatina fulica or "giant African snail" is an exotic species, considered to be one of the world's hundred most invasive species, causing serious environmental damages. In the present study we report, for the first time, the occurrence of Aelurostrongylus abstrusus infecting A.fulica in the Amazon region. This nematode is described parasitizing mainly the pulmonary system of felines, which causes "aelurostrongilose", also known as feline cardio-pulmonary strongyloidosis. New morphometric data of third stage larvae are presented herein. The present study demonstrated that 40 percent of all the snails were infected by A. abstrusus. Achatina fulica specimens were collected from three different areas in Manaus namely: rural; east and west areas. The east area presents the highest prevalence of 80 percent. The large number of A.fulica found in inhabited areas increases the chances of emergent zoonoses, which highlights the need of further studies so as to better control this disease.

Achatina fulica ou "caramujo africano" é uma espécie exótica, considerada uma das cem piores espécies invasoras do mundo, causando sérios danos ambientais. No presente estudo foi registrado, pela primeira vez, a ocorrência do Aelurostrongylus abstrusus infectando o A.fulica na região amazônica. Esse nematóide é descrito parasitando principalmente o sistema pulmonar de felinos, causando a "aelurostrongilose", também conhecida como estrongiloidose cardio-pulmonar felina. Novos dados morfométricos de larvas de terceiro estágio são apresentados. Dos 45 caramujos coletados, 40 por cento estavam infectados por larvas de A. abstrusus. Especimens de Achatina fulica foram coletados em três áreas da cidade de Manaus: rural, leste e oeste. A zona leste apresentou a maior prevalência de 80 por cento. O grande número de A.fulica encontrado em áreas habitadas aumenta as chances de ocorrência de zoonoses emergentes e destaca a necessidade de mais estudos para o melhor controle da doença.

Calibration and evaluation of field cage for oviposition study with Aedes (Stegomyia) aegypti female (L.) (Diptera: Culicidae) / Calibração e avaliação de semi-campo para estudos de oviposição para fêmeas de Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae)

Differences among results gathered from insect behavior studies conducted in laboratory and field situations are due to ambient variables that differ greatly between both environments. In laboratory studies the environmental conditions can be controlled whereas in field temperature, humidity and air velocity vary uncontrollably. The objective of this study was to calibrate and evaluate an experimental area (field cage) (14 x 7 x 3.5 m) subdivided into eight test cages (2.5 x 2.5 x 2 m) for use in behavioral oviposition tests of Aedes aegypti (L.) mosquitoes for developing a new methodology to assess attractants and oviposition traps. Test cage calibration involved: (1) minimal experiment duration tests; (2) optimal female release number per traps test and (3) trap placement tests. All tests used gravid A. aegypti females; 3-4 days post blood meal and the sticky trap MosquiTRAP® to catch adults. Ninety percent of the females released were recaptured 2h after the beginning of the experiment, and this allowed up to 32 test repetitions/day to be conducted in the field cage. The minimum number of females necessary to conduct statistical analyses was 20 females/trap/test per cage. No significant difference was found in the behavioral response of gravid females to four different trap positions within test cages. Field trapping results with attractant were similar to those in the field cage. Therefore, the field cage could replace field trapping for evaluating at least mosquito traps and oviposition attractants for A. aegypti.

Discrepâncias entre resultados de estudos de comportamento de insetos em laboratório e em campo ocorrem devido a variáveis encontradas entre os ambientes. Enquanto em laboratório as condições são controladas, em campo os insetos são avaliados em condições variáveis de temperatura, umidade e velocidade do ar. O objetivo deste trabalho foi calibrar e avaliar uma área experimental (14 x 7 x 3,5 m) contendo oito gaiolas de teste (2,5 x 2,5 x 2 m), para estudos comportamentais de oviposição para Aedes aegypti (L.) visando desenvolver uma nova metodologia para avaliar atraentes e armadilhas de oviposição em semi-campo. A calibração consistiu na (1) determinação do tempo de realização dos experimentos e no (2) número de fêmeas liberadas por teste e na (3) avaliação das posições das armadilhas no interior das gaiolas de teste. Fêmeas de A. aegypti de 3-4 dias após repasto sangüíneo e MosquiTRAP® foram utilizadas nos experimentos. Noventa por cento das fêmeas liberadas foram recapturadas após 2h do início dos experimentos, permitindo a realização de até 32 repetições/dia. A amostra mínima de fêmeas por experimento para a realização de análises estatísticas foi limitada a 20 fêmeas/armadilha/gaiola. Não foi observada diferença na resposta comportamental das fêmeas nas diferentes posições avaliadas. Resultados com MosquiTRAP em área urbana foram semelhantes aos do semi-campo. Portanto, a metodologia pode substituir os testes de campo para avaliar pelo menos armadilhas e atrativos de oviposição para A. aegypti.