Biomedical subjects
Publications and source records attributed to E W Kitajima.
Leptomonas pessoai from the reduviid hemipteron Zelus leucogrammus, was cloned. The original strain (ATCC 30252) and clones can differentiate from promastigote to opisthomastigote. Differentiation is faster at high temperature (37 C) and in a defined medium as compared with a complex medium. It is suggested that Leptomonas pessoai be designated Herpetomonas samuelpessoai.
The fine structure of the promastigotes of Herpetomonas sp. (Leptomonas pessoai) kept in a defined medium at 28 degrees C is described. This portozoon reveals several features in common with other trypanosomatids. A membrane-bounded organelle measuring 0.2 to 0.8 mum in diameter, similar to that described as peroxisome in Crithidia fasciculata, was also observed. A large cavity, located between the nucleus and the kinetoplast and containing vesicles and small particulate material is discussed in this paper.
The sperm of the blood fluke Schistosoma mansoni consist of a bulbous head 8 by 2 mum, with a rounded anterior tip and tapering posterior region, followed by a relatively short flagellum ca. 20 mum long. Electron microscopic observations revealed that these sperm are devoid of an acrosome, while a few undifferentiated mitochondria accumulate at the anterior part of the head. The nucleus appears dense, except for some electron-lucent patches. The flagellum starts at the basal body, posterior and slightly lateral to the nucleus, and the axial complex is of the 9 + 0 type. A layer of microtubules runs longitudinally, just beneath the plasmalemma, from the anterior part of the head to the initial part of the flagellum, where they overlap with the axial complex. It is suggested that this relatively rudimentary type of the S. mansoni sperm is probably related to the low activity required for fertilization.
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The understanding of the stimuli perceived by these parasitoids to accept and exploit a potential host may support the development of artificial hosts for their in vitro rearing. The most common structures involved in the host selection process in parasitoids are the antenna and the ovipositor. Sensilla present on these structures are involved in host recognition and acceptance, and the identification of which kind of stimulus (physical or chemical) is perceived by the sensilla could provide data about the host characteristics that elicit the parasitism behavior. The antenna and ovipositor of the wasps Trichogramma galloi and T. pretiosum were studied to identify their sensillar structure and their possible functions in the host selection process, as a support to the development of an artificial host for the in vitro rearing of these parasitoids. Seven sensilla and one setiform structure were present on the antenna of both parasitoid species, with a mixed, chemo-, or mechanoreception function. The ovipositor has four different sensilla and their role in the host evaluation is suggested.
Tomato spotted wilt virus (TSWV) particles were identified in thin sections and in crude extracts of leaves from plants infected with different TSWV isolates, using gold labelled protein A and antibodies prepared against purified virus particles or against nucleocapsid preparations. In addition, both in thin sections and in dip preparations aggregates were detected using either gold-labelled antiserum. These aggregates were not detected using antisera against envelope proteins or against the non-structural protein NSs. They were the only detectably labelled material in preparations made from plants infected by morphologically defective isolates of TSWV, i.e. isolates that did not produce enveloped particles. The aggregates were discerned in dip preparations as cloudy amorphous structures having a cottonwool boll-like appearance. These 'cotton bolls' were interpreted as being the in vitro structures of the nucleocapsid aggregates occurring in plant cells infected by isolates maintained by mechanical inoculation and are the only structures in cells infected by morphologically defective isolates (Ie, 1982; Kitajima et al., 1992). The detection of the 'cotton boll-like' structures in crude extracts provides an adequate and rapid method to establish the presence of nucleocapsid aggregates in cells of infected plants, irrespective of whether they are infected by morphologically defective isolates or not.
In an attempt to detect rotavirus and adenovirus prevalence among other enteropathogens (bacteria and parasites) in diarrhoea, three hundred fecal samples originating from children living in Goiânia city (Goiás state, Brazil) were analysed. Rotavirus was found to be the only pathogen in 47 cases, and associated with other infectious agents in 21 cases. 97.0% positive samples of rotavirus showed an electrophoretic pattern characteristic of subgroup II. Adenovirus was found in 7 cases, and associated with other microorganisms in 1 case. Three methods were applied for virological analyses: enzyme immunoassay for rotavirus and adenovirus (EIARA), polyacrylamide gel electrophoresis (PAGE) and immunoelectron microscopy (IEM). The concordance among the three methods was 92.8%, PAGE and EIARA agreed in 95.8%, and IEM and EIARA agreed in 100.0%.
In order to detect rotavirus and adenovirus 557 feces samples from hospitalized children (0-5 years of age) were analysed from June 1987 to July 1990 in Goiânia city. Two hundred and ninety one samples were from children with diarrhoea and 266 were from children without diarrhoea. Amongst this later group, 64 samples were from children from the nursery. Two hundred and sixty one out of 557 samples were analysed by immunoelectron microscopy (IEM), polyacrylamide gel electrophoresis (SDS-PAGE) and enzymatic immunoassay for rotavirus and adenovirus (EIARA) whereas the rest (296 samples) were analysed by SDS-PAGE and EIARA. Positivity of rotavirus and adenovirus was 17.2% and 2.1% respectively. Concerning rotavirus and adenovirus there was 29.2% and 2.4% positivity within the group with diarrhoea and 4.1% and 1.5% positivity amongst children without diarrhoea (p < 0.05). Rotavirus were more prevalent amongst children which age ranged from 1 to 11 months of age. No newborn child from the nursery was positive for rotavirus. Adenovirus were detected amongst children from 1 to 3 years of age. Rotavirus circulation peak occurred between May and August (p < 0.05) and no positive case was detected from December to February. Two hundred out of 291 diarrheic samples were also studied concerning bacteria and pathogenic parasites and equal percentages (17.0%) were found for both rotavirus and pathogenic bacteria. Eighty nine samples of rotavirus were detected by SDS-PAGE and 86 of these (96.6%) belonged to the subgroup II with 13 different electrophoretic patterns. Predominance of a given electrophoretic profile was observed in each year of the study.