Imatinib activity on Schistosoma mansoni

Imatinib, a drug used for treatment of human chronic myeloid leukaemia, due to its activity against protein kinases, has been also evaluated in vitro against Schistosoma mansoni showing high schistosomicidal activity. In the present experiments imatinib activity in vitro was confirmed at the doses of 25 µM, 50 µM and 100 µM. The first drug activity observed with the lower dose was interruption of egg-laying and with the higher dosages was the death of the worms. In mice infected with S. mansoni no activity was found even with 1,000 mg/kg/day, 500 mg/kg/day, single oral dose or when administered for three consecutive days. This is another example of the difference of results related to in vitro and in vivo trials using S. mansoni worms.     

Larval description of Simulium (Notolepria) cuasiexiguum and Simulium (Chirostilbia) obesum and new records of black fly species (Diptera: Simuliidae) in the states of São Paulo and Minas Gerais, Brazil

We describe the larval stage of Simulium cuasiexiguum Shelley, Luna Dias, Maia-Herzog & Lowry and Simulium obesum Vulcano and provide new distribution records of four black fly species in the State of S?o Paulo (Simulium cuasiexiguum, Simulium metallicum s.l. Bellardi, Simulium stellatum Gil Azevedo, Figuer6 & Maia-Herzog and Simulium oyapockense s.l. Floch & Abonnenc) and three species in the State of Minas Gerais (Simulium duodenicornium Pepinelli, Hamada & Trivinho-Strixino, Simulium obesum and Lutzsimulium pernigrum Lutz).     

Molecular circumscription of the blackfly Simulium oyapockense from South America

Problems related to the identity of Simuliidae species are impediments to effective disease control in Amazonia. Some of these species, such as Simulium oyapockense Floch & Abonnenc, 1946 (Diptera: Simuliidae), are vectors of the organisms that cause onchocerciasis and mansonellosis diseases. This blackfly species has a wide distribution in South America, and it is suspected of being a complex of cryptic species. The aim of this study is to characterize the nominal species S. oyapockense using partial COI gene sequences. Seven populations of S. oyapockense (morphologically identified) were analysed, including one from its type-locality. The other six populations were collected in Brazil and in Argentina. A taxon collected in Amazonas state, Brazil, with adults similar to S. oyapockense but with distinct pupae, was also included in the analysis (Simulium ‘S’). The nominal species S. oyapockense is circumscribed, and its geographical distribution is restricted to areas north of the Amazon River. Populations of S. oyapockense s.l. collected south of the Amazon River comprise a species complex that needs to be evaluated using integrative taxonomy. Simulium ‘S’ represents a species with unique morphological and molecular characteristics. Distinguishing cryptic species is a prerequisite for reducing the taxonomic impediment, especially in medically important taxa.     

Cytotaxonomy of four species in the Simulium perflavum species group (Diptera: Simuliidae) from Brazilian Amazonia

Polytene chromosomes of four members of the Simulium perflavum species group in Brazil are described, and a standard map for the species group is presented. Simulium rorotaense Floch & Abonnenc, S. perflavum Roubaud and an undescribed species (S.‘X’) are chromosomally conservative, each representing a single species with a unique preimaginal habitat. Chromosomal, morphological and ecological evidence indicates that S. maroniense Floch & Abonnenc, previously considered synonymous with S. rorotaense, is a good species. Independent morphological and chromosomal analyses yielded 99.4% agreement in separating larvae of S. rorotaense and S. maroniense. The two species can be distinguished by gill morphology or by a subterminal inversion on the long arm of chromosome III. Simulium maroniense consists of at least four cytotypes, each with different sex chromosomes and autosomal polymorphism profiles and associated with a particular landscape type, altitude, temperature regime or geographical location. Simulium rorotaense and S. maroniense share one unique inversion, as do S. perflavum and S. ‘X’, indicating two pairs of sister species. The anthropogenic S. perflavum probably dispersed into Central Amazonia sometime after the mid-1970s.     

Photo-induced toxicity of anthracene in the Antarctic shallow water amphipod, <Emphasis Type="Italic">Gondogeneia antarctica</Emphasis>

The photo-induced toxicity of anthracene was investigated as the mortality in Antarctic shallow water amphipod, Gondogeneia antarctica, at different concentrations of anthracene and different periods of exposure to natural sunlight and artificial UVA and UVB radiations. When exposed to natural sunlight, animals contaminated in the dark and placed in clean water or in anthracene solutions showed different degrees of mortality, dose–time dependent. Effects were even more evident when these animals were exposed to artificial UVA or UVB radiations. Depuration seemed to be a slow process. The effects of UV radiation and anthracene alone and the effects of the interactions of these two stressors implied that solar radiation is an important parameter that deserves consideration in the environmental assessment of polycyclic aromatic hydrocarbons in Antarctic coastal waters. G. antarctica proved to be a good bioindicator for the phototoxicity of anthracene in Antarctic shallow waters.     

Effects of Phylloicus case removal on consumption of leaf litter from two Neotropical biomes (Amazon rainforest and Cerrado savanna)

Limnology - Phylloicus (Trichoptera, Calamoceratidae) is a stream invertebrate widely distributed across Neotropical biomes, which larvae use allochthonous leaf litter as food resource and to build...