E.W. Kitajima

Isometric, viruslike particles in the green peach aphid, Myzus persicae: Their intracellular localization and Distribution within the aphid body

Abstract Isometric, viruslike particles (VLP), 20–25 nm in diameter, were consistently found in some organs of the green peach aphids, Myzus persicae, from a stock colony of the Virus Department, Instituto Agronomico, Campinas, and of the Department of Plant Biology, University of Brasilia. They are presumed to be identical to those described by Peters (1967) in extracts of M. persicae in the Netherlands and considered to be a latent virus of this aphid. VLP were detected only in aphids up to 3 weeks old, even when newborn nymphs were immediately separated from the colony after their birth and raised separately. They were found initially in the midgut and, about 1 week later, in the nerve ganglia and salivary gland but not in other organs. In the midgut, VLP were noticed in the lumen, associated with the microvilli, or in the epithelial cells within membrane-bound cavities, basal infoldings of the plasmalemma, and embedded in the basal membrane. Clusters of vesicles associated with the presence of VLP were commonly seen in the cytoplasm. In the nervous ganglia, VLP often occurred forming crystalline aggregates of various sizes within the internal mass of axons and glial processes. Only rarely, particles were noticed in the peripheral neurons. In a few instances, VLP were also seen in the rhabdomere of the compound eye. In the salivary gland cells, VLP commonly appeared within deep infoldings of the plasmalemma at the basal part, forming a single layer of tight and hexagonally arranged particles. Less frequently, VLP were observed within secretion granules and large membrane-bound cavities. Histological observations suggest that these VLP might be transovarially transmitted. The midgut seems to be the main center of VLP multiplication, whereas the salivary gland and nervous ganglia appear to be preferential sites for their accumulation.

Nonoccluded baculovirus- and filamentous virus-like particles in the spotted cucumber beetle, diabrotica undecimpunctata (coleoptera: chrysomelid)

Abstract Nonoccluded baculovirus-and filamentous virus-like particles were found in nuclei of hemocytes or midgut cells of field-collected spotted cucumber beetles. Each type of particle was associated with a different type of virogenic stroma containing various viral components similar to those referred to as capsid, nucleocapsid, viroplasm, and viral envelope in other known baculovirus infections. Nucleocapsids of the virus which occured only in hemocytes were rod-shaped particles approximately 230 nm long and 52 nm wide and were enveloped singly by a trilaminar unit membrane. Enveloped and partly enveloped particles appeared to be released from the nucleus to the cytoplasm by budding through the nuclear envelope acquiring additional membranes. The nucleocapsids of the virus which occurred only in nuclei of midgut cells were filamentous particles with an average diameter of 25 nm and variable length up to 2 μm. Some extremely long particles were bent almost 360° near the middle, resulting in a hairpin-like configuration. The particles were always enveloped singly. No particles budding through the nuclear envelope were observed.

Reovirus-like particles and their vertical transmission in the Mexican bean beetle, Epilachna varivestis (Coleoptera: Coccinellidae)

Abstract Examination of thin sections of organs and tissues from the Mexican bean beetle, Epilachna varivestis , adults and larvae revealed the consistent presence of isometric, reovirus-like particles in the cytoplasm and rarely in the nuclei. Cytoplasmic inclusions having a dense and finely granular matrix with virus-like particles at their periphery were noticed occasionally. These inclusions were, however, very frequent in the nurse cells in the germarium of the ovariole. Virus-like particles were found in the cytoplasm of oocytes and eggs as well as embedded in the nuclei of sperm, thus suggesting vertical transmission of these particles, and explaining the 100% infection of the Mexican bean beetle colony maintained at the Virology and Biocontrol Laboratory of the University of Arkansas. Partially purified extracts from ovarioles or entire beetles contained particles which, in negatively stained preparations, resembled reoviruses without the external protein coat. It is suggested that these particles represent a latent virus of the Mexican bean beetle.

ULTRASTRUCTURAL OBSERVATIONS ON Trypanosoma (Herpetosoma) rangeli IN THE SALIVARY GLANDS OF Rhodnius ecuadoriensis (Hemiptera, Reduvidae)

Fue realizado un estudio ultraestructural de las glandulas salivares del triatomino Rhodnius ecuadoriensis experimentalmente infectado por el tripanosomatideo, Trypanosoma (Herpetosoma) rangeli, con la finalidad de documentar los aspectos basicos de la infeccion glandular por este flagelado. Gran numero de formas epimastigotes fueron encontradas en la hemolinfa que bana la parte externa de las glandulas en el hemoceloma. Algunos flagelados parecian intimamente asociados a la membrana basal del epitelio glandular y varios de ellos parecian estar iniciando el proceso de su invasion, rompiendo la lamina basal con el flagelo. En el interior de las celulas glandulares observamos que, T. rangeli se presentaba en la forma de esferomastigotes, celulas redondeadas rodeadas externamente por un flagelo, que envolvia apretadamente el parasito. En la luz glandular tambien observamos gran numero de epimastigotes mezclados con los productos de la secrecion glandular; el material presento apenas pocas formas paramastigotes y trypomastigotes identificadas de manera inequivoca. El significado de los paramastigotes en el ciclo evolutivo del T. rangeli aguarda futuros estudios

Levantamento preliminar de viroses de plantas cultivadas nos arredores de Manaus, Am

Um levantamento preliminar de viroses de plantas cultivadas nos arredores de Manaus foi feito em marco de 1977. Diversas propriedades particulares e campos experimentais foram inspecionados, anotando-se as plantas exibindo sintomatologia suspeita. A verificacao da sua possivel etiologia viral foi feita atraves de testes de transmissao, serologia e exames electrono microscopicos. Foram constatadas diversas viroses em tomateiro, pimentao, quiabeiro, feijoeiro, cucurbitaceas, soja, feijao-de-asa, milho. etc. Como regra geral, ao contrario do que sucede no Sul do Pais, as viroses transmitidas por afideos foram de ocorrencia rara, presumivelmente porque as condicoes climaticas da regiao seriam desfavoraveis a biologia desses insetos.