Caracterização do Tomato chlorotic spot virus isolado de jiló no Vale do Paraíba, Estado de São Paulo

Os tospovírus são responsáveis por perdas significativas em diversas culturas, principalmente solanáceas. No município de São José dos Campos (SP), plantas de jiló (Solanum gilo) apresentando sintomas de mosaico, bolhosidades, nanismo e queda acentuada da produção foram coletadas para análise. Visando a caracterização do agente causador dos sintomas, testes biológicos, elétrono microscópicos, sorológicos e moleculares foram realizados. Através de inoculação mecânica em plantas indicadoras das famílias Amaranthaceae, Chenopodiaceae e Solanaceae obtiveram-se resultados típicos aos esperados para tospovírus. Ao microscópio eletrônico de transmissão, observaram-se, em contrastação negativa, partículas pleomórficas com diâmetro entre 80 e 110 nm e em cortes ultra-finos partículas presentes em vesículas do retículo endoplasmático. Através de DAS-ELISA, identificou-se o Tomato chlorotic spot virus (TCSV). A partir de RNA total extraído de folhas infetadas, amplificaram-se, via RT-PCR, fragmentos correspondentes ao gene da proteína do capsídeo (cp) os quais foram seqüenciados e comparados com outros depositados no "GenBank". A homologia de nucleotídeos e aminoácidos deduzidos foi respectivamente de 99 e 95% quando comparada com seqüências de isolados de TCSV. A comparação com as outras espécies do gênero Tospovirus apresentou valores de homologia entre 72 e 84%. Estes resultados confirmam a identidade deste vírus como pertencente à espécie TCSV, que é predominante no Estado de São Paulo e importante patógeno de outras plantas cultivadas. Além disso, variedades de jiló quando inoculadas foram susceptíveis tanto ao TCSV como às espécies Tomato spotted wilt virus (TSWV) e Groundnut ringspot virus (GRSV).

Erigeron bonariensis: hospedeira alternativa do Lettuce mosaic virus no Brasil

O gênero Erigeron (Asteraceae), de plantas da vegetação espontânea, encontra-se amplamente disseminado nas regiões Sul e Sudeste do Brasil, sendo freqüentemente encontrado em lavouras perenes e anuais. Plantas de E. bonariensis com sintoma de mosaico, típico do induzido por vírus, foram coletadas no município de São Paulo e submetidas a análises ao microscópio eletrônico de transmissão, testes biológicos, sorológicos e moleculares. Em cortes ultrafinos do tecido foliar original, observaram-se inclusões tubulares e cata-ventos dispersos no citoplasma. Através de inoculação mecânica, somente Chenopodium amaranticolor, C. quinoa, Nicotiana benthamiana e N. clevelandii foram infetadas. Os resultados obtidos em ELISA foram negativos quando se utilizaram antissoros contra o Turnip mosaic vírus (TuMV) e diferentes estirpes do Potato virus Y (PVY), constatando-se relacionamento sorológico com o Lettuce mosaic virus (LMV). Com a utilização de oligonucleotídeos específicos para LMV amplificaram-se fragmentos esperados de aproximadamente 280 pb, que seqüênciados confirmaram a identidade do vírus. A ocorrência do LMV em E. bonariensis, gênero da mesma família botânica da alface (Lactuca sativa), é de grande importância, pois talvez possa atuar como reservatório para infecção de campos de produção de alface. Este é o primeiro relato, no Brasil, de vírus infetando Erigeron sp., o qual só havia sido reportado como hospedeira natural do Bidens mottle virus (BiMoV) e do Tomato spotted wilt virus (TSWV) nos Estados Unidos.

Tomato chlorotic spot virus in hydroponically-grown lettuce in São Paulo State, Brazil

In the regions of Campinas and Sumaré, São Paulo, Brazil, hidroponically grown crops of Lettuce (Lactuca sativa) cv. Verônica, which showed virus-like symptoms were examined by electron microscope, biological, serological and molecular tests. Pleomorphic, enveloped particles (80-100 nm in diameter) were always detected in these samples. Experimentally inoculated host plants, including lettuce, reacted with tospoviruses-induced symptoms. Some differences were observed in Gomphrena globosa, which reacted by showing local lesions and systemic mosaic. Two isolates of Tomato chlorotic spot virus (TCSV) were identified by DAS-ELISA and by RT-PCR. The sequencing and alignment of the RT-PCR coat protein amplified fragments have indicated a high degree of homology with the TCSV sequences stored in the GenBank. This is the first report of losses due to a virus from the genus Tospovirus in commercial hydroponic lettuce crops in Brazil. Further epidemiological studies are needed for better understanding the spread of the virus in hydroponic crops, since Tomato spotted wilt virus (TSWV) is reported to spread through the nutritive solution.

First identification of natural infection of Rickettsia rickettsii in the Rhipicephalus sanguineus tick, in the State of Rio de Janeiro

The Brazilian Spotted Fever (BSF) is a zoonotic disease caused by Rickettsia rickettsii and transmitted by ticks of the genus Amblyomma, more frequently, Amblyomma cajennense. The aim of this paper was to report the first molecular detection of R. rickettsii on R. sanguineus naturally infected in Rio de Janeiro, Brazil. Ticks were collected from dogs in a rural region of Resende municipality, Rio de Janeiro State, Brazil (22º30'9.46"S, 44º42'44.29"WO), where occurred five human cases of BSF in 2006. The ticks were identified under a stereoscopic microscope and separated in pools by stages, species and sex. DNA extraction was carried out using QIAamp DNA Mini Kit (QIAGEN®). The DNA was submitted to PCR amplification using 04 set of primers: Rr190.70p/Rr190.602n (OmpA, 532bp), BG1-21/BG2-20 (OmpB, 650bp), Tz15/Tz16 (17 kDa protein-encoding gene, 246bp) and RpCS.877p/RpCS.1258n (gltA, 381bp). PCR products were separated by electrophoresis on 1% agarose gels and visualized under ultraviolet light with ethidium bromide. PCR products of the expected sizes were purified by QIAquick® and sequenced by ABI PRISM®. The generated nucleotide sequences were edited with using Bioedit® software and compared with the corresponding homologous sequences available through GenBank, using Discontiguous Mega Blast (http://www.ncbi.nlm.nih.gov). It was confirmed R. rickettsii by sequencing of the material (GenBank FJ356230). The molecular characterization of R. rickettsii in the tick R. sanguineus emphasizes the role of dogs as carriers of ticks from the environment to home. Moreover, this result suggests that there is a considerable chance for active participation of R. sanguineus as one of tick species in the transmission of R. ricketsii to human being in the Brazilian territory.

Anti-Rickettsia spp. antibodies in free-ranging and captive capybaras from southern Brazil

Capybaras (Hydrochaeris hydrochaeris) are among the main hosts of Amblyomma spp. ticks, which is able to transmit Rickettsia species to human beings and animals. Since they are often infested with potential vector ticks, capybaras may be used as sentinels for rickettsiosis, such as the Brazilian Spotted Fever. The aim of the present study was to determine the prevalence of antibodies against Rickettsia spp. using the indirect immunofluorescence assay (IFA) in 21 free-ranging and 10 captive animals from the Zoological Park of the 'Bela Vista Biological Sanctuary' (BVBS), Itaipu Binational, Foz do Iguaçu, Southern Brazil. Antigens of six rickettsial species already identified in Brazil (Rickettsia rickettsii, R. parkeri, R. bellii, R. rhipicephali, R. amblyommii and R. felis) were used for IFA. Ticks from each capybara were collected for posterior taxonomic identification. A total of 19 (61.3%) samples reacted to at least one of tested species. Seropositivity was found in 14 (45.2%), 12 (38.7%), 5 (16.1%), 4 (12.9%), 3 (9.7%) and 3 (9.7%) animals for R. rickettsii, R. bellii, R. parkeri, R. amblyommii, R. felis and R. rhipicephali, respectively. Two captive capybaras presented suggestive titers of R. rickettsii infection and one sample showed homologous reaction to R. parkeri. Only one free-ranging capybara presented evidence R. bellii infection. Ticks collected on capybaras were identified as Amblyomma dubitatum e Amblyomma sp. Results evidenced the rickettsial circulation in the area, suggesting a potential role of capybaras on bacterial life cycle.

Microglia and neurons in the hippocampus of migratory sandpipers

The semipalmated sandpiper Calidris pusilla and the spotted sandpiper Actitis macularia are long- and short-distance migrants, respectively. C. pusilla breeds in the sub-arctic and mid-arctic tundra of Canada and Alaska and winters on the north and east coasts of South America. A. macularia breeds in a broad distribution across most of North America from the treeline to the southern United States. It winters in the southern United States, and Central and South America. The autumn migration route of C. pusilla includes a non-stop flight over the Atlantic Ocean, whereas autumn route of A. macularia is largely over land. Because of this difference in their migratory paths and the visuo-spatial recognition tasks involved, we hypothesized that hippocampal volume and neuronal and glial numbers would differ between these two species. A. macularia did not differ from C. pusilla in the total number of hippocampal neurons, but the species had a larger hippocampal formation and more hippocampal microglia. It remains to be investigated whether these differences indicate interspecies differences or neural specializations associated with different strategies of orientation and navigation.

Radiographic analysis in castor bean seeds (Ricinus communis L.)

Castor bean cropping has great social and economic value, but its production has been affected by factors such as low quality seeds used for sowing. The quick and precise evaluation of seed quality by x-ray test is known as an effective method to evaluate seed lots, but little is known about the interpretation between of the type of radiographic image and the seed quality correlation. The potential of x-ray analysis as a marker of seed physiological quality and as an initial process for the implementation of the use of computer-assisted image analysis was investigated using castor bean seeds of the different cultivars. The seeds were classified according to internal morphology visualized in the radiography and subjected to the germination test, emergency and seedling growth rate. It was possible to identify the different types of internal tissues, morphological and physical damage in castor bean seeds using the x-ray test. Tissues generating translucent images, embryo deformation, or tissues with less than 50% of endosperm reserves or spotted, negatively affected the physiological potential of the seed lots. Radiographic analysis is effective as an instrument to improve castor bean seed lot quality. This non destructive analysis allows the prediction of seedling performance and enabled the selection of high-quality seeds under the standards of a sustainable and precision agriculture