RESUMO
Bacillus thuringiensis subsp. medellin produces numerous proteins among which 94 kDa known as Cry11Bb, has mosquitocidal activity. The mode of action of the Cry11 proteins has been described as similar to those of the Cry1 toxins, nevertheless, the mechanism of action is still not clear. In this study we investigated the in vivo binding of the Cry11Bb toxin to the midgut of the insect species Anopheles albimanus, Aedes aegypti, and Culex quinquefasciatus by immunohistochemical analysis. Spodoptera frugiperda was included as negative control. The Cry11Bb protein was detected on the apical microvilli of the midgut epithelial cells, mostly on the posterior midgut and gastric caeca of the three mosquito species. Additionally, the toxin was detected in the Malpighian tubules of An. albimanus, Ae. aegypti, Cx. quinquefasciatus, and in the basal membrane of the epithelial cells of Ae. aegypti midgut. No toxin accumulation was observed in the peritrophic membrane of any of the mosquito species studied. These results confirm that the primary site of action of the Cry11 toxins is the apical membrane of the midgut epithelial cells of mosquito larvae.
Assuntos
Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Culicidae/metabolismo , Aedes/efeitos dos fármacos , Aedes/metabolismo , Animais , Anopheles/efeitos dos fármacos , Anopheles/metabolismo , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/toxicidade , Culex/efeitos dos fármacos , Culex/metabolismo , Culicidae/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Imuno-Histoquímica , Larva/metabolismo , Túbulos de Malpighi/efeitos dos fármacos , Túbulos de Malpighi/metabolismoRESUMO
Bacillus thuringiensis subsp. medellin produces numerous proteins among which 94 kDa known as Cry11Bb, has mosquitocidal activity. The mode of action of the Cry11 proteins has been described as similar to those of the Cry1 toxins, nevertheless, the mechanism of action is still not clear. In this study we investigated the in vivo binding of the Cry11Bb toxin to the midgut of the insect species Anopheles albimanus, Aedes aegypti, and Culex quinquefasciatus by immunohistochemical analysis. Spodoptera frugiperda was included as negative control. The Cry11Bb protein was detected on the apical microvilli of the midgut epithelial cells, mostly on the posterior midgut and gastric caeca of the three mosquito species. Additionally, the toxin was detected in the Malpighian tubules of An. albimanus, Ae. aegypti, Cx. quinquefasciatus, and in the basal membrane of the epithelial cells of Ae. aegypti midgut. No toxin accumulation was observed in the peritrophic membrane of any of the mosquito species studied. These results confirm that the primary site of action of the Cry11 toxins is the apical membrane of the midgut epithelial cells of mosquito larvae.
Assuntos
Animais , Culicidae , Aedes , Anopheles , Culex , Células Epiteliais , Imuno-Histoquímica , Larva , Túbulos de MalpighiRESUMO
Taenia solium has a complex life cycle. Its cysticercus can lodge in the brain, causing neurocysticercosis (NCC), and the adult tapeworm's survival in the intestine results in taeniasis. In this study, the in situ detection of previously described glycoprotein antigens used for serological diagnosis of NCC and the detection of other glycoconjugates was explored in cysticerci and the surrounding porcine tissue to understand their potential role in pathogenesis. Immunohistochemistry with an antiserum specific for glycoprotein antigens rich in N-linked carbohydrates and in situ histochemistry with a battery of lectins that have affinity to a variety of glycoconjugates were performed. The glycoconjugates rich in N-linked carbohydrates were detected in the vesicular fluid and tegument of the vesicular membrane and scolex, where the parasite has direct contact with the host tissues during cysticercosis and taeniasis, respectively. Additionally, as the inflammatory response progressed, the parasite's antigenic glycoproteins were also detected in the cytoplasm of inflammatory cells in the surrounding granuloma. In contrast, the spiral canal tegument, which will be exposed to intestinal enzymes in taeniasis, had N-acetyl-galactosamine-rich mucins. Thus, the differential saccharidic composition in T. solium metacestode structures may be important for the survival of the parasite in different host sites.
Assuntos
Antígenos de Helmintos/análise , Cisticercose/imunologia , Cysticercus/imunologia , Glicoproteínas/análise , Taenia solium/imunologia , Animais , Antígenos de Helmintos/imunologia , Antígenos de Helmintos/isolamento & purificação , Western Blotting , Cisticercose/parasitologia , Epitopos/análise , Epitopos/imunologia , Glicoconjugados/análise , Glicoconjugados/imunologia , Glicoconjugados/isolamento & purificação , Glicoproteínas/imunologia , Glicoproteínas/isolamento & purificação , Interações Hospedeiro-Parasita/imunologia , Soros Imunes/biossíntese , Soros Imunes/imunologia , Imuno-Histoquímica , Lectinas/imunologia , SuínosRESUMO
Taenia solium metacestodes cause cysticercosis in both humans and pigs. In the former host species, the central nervous system involvement (neurocysticercosis (NCC)) may range from asymptomatic to life-threatening, but little is known about the corresponding variation in tissue response due to the difficulty in obtaining parasite-infected brain biopsies. The use of pigs as animal models for cysticercosis is ideal because the histological description of the animal's response around the parasites resembles the one recorded in human specimens. In this study the histological features of the immune response in swine were complemented by immunohistochemical analysis to determine the phenotype of the inflammatory cells. The presence of mononuclear cells and eosinophils, and the co-localization of MHC-II with B lymphocytes and monocytes/macrophages within the granulomas surrounding the parasites, were features that closely resembled the descriptions made in prior studies with human specimens. In addition, there were novel findings such as the upregulation of the adhesin CD44 in cells resembling monocytes/macrophages, eosinophils and in astrocytes from the central nervous system. The upregulation of CD44 may be important for the recruitment of inflammatory cells to the site of the lesion. Finally, the presence of null-gamma delta-T cells since stage I of the immune response was similar to the early detection of these cells in mouse models for cysticercosis.
Assuntos
Cisticercose/imunologia , Cisticercose/patologia , Doenças dos Suínos/imunologia , Doenças dos Suínos/parasitologia , Animais , Encéfalo/imunologia , Encéfalo/parasitologia , Encéfalo/patologia , Cisticercose/veterinária , Modelos Animais de Doenças , Coração/parasitologia , Receptores de Hialuronatos/análise , Imuno-Histoquímica , Inflamação/imunologia , Inflamação/patologia , Inflamação/veterinária , Músculo Esquelético/imunologia , Músculo Esquelético/parasitologia , Músculo Esquelético/patologia , Miocárdio/imunologia , Miocárdio/patologia , Suínos , Doenças dos Suínos/patologia , Taenia solium/crescimento & desenvolvimento , Taenia solium/imunologia , Regulação para CimaRESUMO
Patients with paracoccidioidomycosis often present pulmonary fibrosis and exhibit important respiratory limitations. Based on an already established animal model, the contribution of viable and non-viable P. brasiliensis propagules to the development of fibrosis was investigated. BALB/c male mice, 4-6 weeks old were inoculated intranasally either with 4x10(6 )viable conidia (Group I), or 6.5x10(6) fragmented yeast cells (Group II). Control animals received PBS. Six mice per period were sacrificed at 24, 48, 72h (initial) and 1, 2, 4, 8, 12 and 16 weeks post-challenge (late). Paraffin embedded lungs were sectioned and stained with H&E, trichromic (Masson), reticulin and Grocott's. During the initial period PMNs influx was important in both groups and acute inflammation involving 34 per cent to 45 per cent of the lungs was noticed. Later on, mononuclear cells predominated. In group I, the inflammation progressed and granulomas were formed and by the 12th week they fussed and became loose. Thick collagen I fibers were observed in 66.6 per cent and 83.3 per cent of the animals at 8 and 12 weeks, respectively. Collagen III, thick fibers became apparent in some animals at 4weeks and by 12 weeks, 83 per cent of them exhibited alterations in the organization and thickness of these elements. In group II mice, this pattern was different with stepwise decrease in the number of inflammatory foci and lack of granulomas. Although initially most animals in this group had minor alterations in thin collagen I fibers, they disappeared by the 4th week. Results indicate that tissue response to fragmented yeast cells was transitory while viable conidia evoked a progressive inflammatory reaction leading to granuloma formation and to excess production and/or disarrangement of collagens I and III; the latter led to fibrosis.
Assuntos
Animais , Masculino , Camundongos , Paracoccidioides/isolamento & purificação , Paracoccidioidomicose/patologia , Fibrose Pulmonar/patologia , Colágeno , Granuloma/patologia , Pulmão/patologia , Camundongos Endogâmicos BALB C , Fibrose Pulmonar/microbiologiaRESUMO
Se estudiaron 100 portadores asintomáticos de Entoameba histolytica o de Entameba hartmanni, ameba no patógena que frecuentemente se confunde con la primera. Se dividieron al azar en dos grupos que recibieron secnidazol o placebo en dosis única. El secnidazol se administró, de acuerdo con la edad, a una dosis promedio de 30 mg/kg. Se hicieron controles parasitológicos post-tratamiento a la una y dos semanas y se encontró que hubo negativización en 56 por ciento de los que recibieron antiamibiano y solo en 24 por ciento de los que recibieron placebo. La tolerancia fue buena, no hubo reacciones tóxicas.
Assuntos
Humanos , Disenteria Amebiana/tratamento farmacológico , Disenteria Amebiana/etiologia , Disenteria Amebiana/terapia , Entamoeba histolytica/patogenicidade , Imidazóis/administração & dosagem , Imidazóis/uso terapêutico , Amebicidas/administração & dosagem , Amebicidas/uso terapêuticoRESUMO
Después de revisar varios trabajos sobre métodos de recuento de huevos de helmintos, analizamos el de Kato Katz y lo comparamos son el método de Beaver modificado. Para este estudio escogimos una comunidad para recuperación de gamines, con una población de 250 estudiantes y 13 profesores, a todos los cuales se les hizo estudio de materia fecal por los dos métodos. El método de Kato Katz detectó más infecciones por Trichuris trichiura, uncinarias y Ascaris Iumbricoides, con diferencia estadíticamente significativa para los dos primeros