RESUMEN

Rabies virus (RABV) is a single stranded RNA genome virus that encodes five proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and RNA dependent polymerase (L). However, RABV seem to be remarkably stable antigenic and genomic differences among isolates from different species have been recognized for many years.Analysis of RABV isolates from different natural reservoirs reveals antigenic variants and/or genetic lineages with specific characteristics, suggesting selection and adaptation of viruses to each of the particular species. Such selections and adaptations are so specific that they allow for the identification of the natural reservoir of origin of a determined isolate.This work was conducted to investigate the genomic and antigenic stability of four different genetic lineages of RABV,originated from different host species, following successive passages in mice. Four RABV isolates (IP4005/10, IP964/06, IP3629/11 and IP4871/11) were inoculated intracerebrally into 3-4 weeks-old mice. After each passage, the viruses were examined in their antigenic profile with a panel of monoclonal antibodies to rabies virus antigens. Viral RNA wasextracted from the 1st, 5th and 10th passages and submitted to reverse transcription (RT) followed by polymerase chain reaction (RT-PCR), sequencing and phylogenetic analyses. Antigenic profile of the isolates did not reveal any recognizable alteration throughout. No nucleotide substitutions were noticed in the final sequences in any of genes sequenced fromthe four RABV isolates, with the exception of one nonsynonymous substitution in the putative protein P in position of amino-acid 222 in the isolate of non-hematophagous bat origin. These findings highlight the high antigenic and genetic stability of RABV, as opposed to the alleged high genomic variability of viruses with RNA genomes. On the other hand, itseems that different isolates may present different degrees of genetic stability, ...

Asunto(s)

RESUMEN

Acanthamoeba is a free-living protozoan widely distributed in the environment, occurring in vegetative trophozoite and resistance cyst stages during its life cycle. It constitutes an etiological agent of Acanthamoeba keratitis, a disease that may cause severe ocular inflammation and blindness. New drugs can be developed from molecules found in plants and thus help in its difficult treatment. Acanthospermum australe (Asteraceae), a plant used in folk medicine, had its effect tested on Acanthamoeba polyphaga. Aqueous and ethanolic extracts of A. austral were obtained from aerial parts for infusion and static maceration, respectively. Concentrations of 10, 5, 2.5, 1.25 and 0.625 mg/ml of the extract were tested against Acanthamoeba polyphaga trophozoites. The cytotoxic effect of the extracts was tested in mammalian cells using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The 10 mg/ml concentration of ethanolic extract was lethal to 100% of the A. polyphaga trophozoites in 24 h and both extracts presented cytotoxic effect against mammalian cells. These findings suggest that the A. austral ethanolic extract may have compounds with relevance to the development of new amoebicidal drugs.

Acanthamoeba é um protozoário de vida livre amplamente distribuído no ambiente, ocorrendo sob a forma trofozoítica (metabolicamente ativa) e cística (de resistência), durante seu ciclo de vida. O protozoário constitui um agente etiológico da Ceratite Amebiana, uma doença que pode causar inflamação ocular severa e cegueira. Novos fármacos podem ser desenvolvidos a partir de moléculas encontradas em plantas e assim ajudar em seu difícil tratamento. Aqui, Acanthospermum australe (Asteraceae), uma planta utilizada na medicina popular, teve seu efeito sobre trofozoítos de Acanthamoeba polyphaga testado. O extrato aquoso e etanólico de A. australe foram obtidos das partes aéreas por infusão e maceração estática, respectivamente. As concentrações 10, 5, 2,5, 1,25 e 0,625 mg/ml dos extratos foram testadas contra trofozoítos do protozoário. O efeito citotóxico dos extratos foi testado em células de mamífero utilizando o ensaio de brometo de 3-[4,5-dimetiltiazol-2-il]-2,5-difeniltetrazólio (MTT). A concentração de 10 mg/ml do extrato etanólico foi letal a 100% dos trofozoítos de A. polyphaga em 24 h e ambos os extratos apresentaram efeito citotóxico contra as células de mamífero. Estes resultados sugerem que o extrato etanólico de A. australe pode ter componentes com relevância para o desenvolvimento de novos fármacos amebicidas.

Asunto(s)

RESUMEN

Adenovirus (AdV), enterovirus (EV), genogroup A rotaviruses (GARV) and Torque teno virus (TTV) are non-enveloped viral agents excreted in feces and so may contaminate water bodies. In the present study, the molecular detection of these viruses was performed in samples of surface water collected from the Arroio Dilúvio, a waterstream that crosses the city of Porto Alegre, RS, Brazil, receiving great volumes of non-treated sewage from a large urban area. Sampling was performed during 2009, in three different occasions (January, April and September). The highest detection rate was observed for EV (64.28%), followed by TTV (28.57%) and AdV (21.43%). Rotaviruses were not detected. More than on kind of tested virus was detected in five (35. 71%) of 14 samples. January was the month with the highest viral detection rate, being all samples, collected in this month, positive for at least one group of tested virus. The correlation between the detection of these different viral agents and environmental factors is discussed. To the knowledge of the authors, this is the first description of viral genomes in water samples taken from the Arroio Dilúvio, Porto Alegre (Brazil).

Adenovírus (AdV), enterovírus (EV), rotavírus (GARV) e Torque teno vírus (TTV) são vírus não envelopados, excretados nas fezes, podendo, assim, contaminar corpos hídricos. No presente estudo, a detecção molecular desses agentes foi realizada em amostras de águas superficiais provenientes do Arroio Dilúvio, o qual cruza a cidade de Porto Alegre-RS, Brasil. As amostras foram coletadas em três meses diferentes (janeiro, abril e setembro) do ano de 2009. A maior taxa de detecção viral foi observada para EV (64,28%), seguida por TTV (28,57%) e AdV (21,43%). Rotavírus não foi detectado. Foi verificada presença simultânea de dois grupos virais em cinco (35,71%) das 14 amostras analisadas. Janeiro foi o mês com a maior taxa de detecção viral, sendo todas as amostras, coletadas nesse mês, positivas para, no mínimo, um grupo viral em estudo. A correlação entre a detecção desses diferentes agentes virais e os fatores ambientais é discutida. Conforme conhecimento dos autores, essa é a primeira descrição de genomas virais em amostras de água provenientes do Arroio Dilúvio, Porto Alegre, Brasil.

Asunto(s)