43 resultados para Meredith, George, 1828-1909
Resumo:
Lagochilascaris minor Leiper, 1909 is a parasitic nematode with its biological cycle still unknown, even though it was found in humans, domestic and silvatic animals. Adult worms, collected by surgical drainage from a human patient from the State of Pará, Brazil, were micrographed using a scanning electron microscope. Morphological aspects of males and females such as cephalic structures, caudal papillae and cuticular patterns were analyzed and compared with the previous descriptions adding new data for the identification of this species.
Resumo:
A total of 25 specimens of Cavia porcellus (guinea pig), 5 Dasyprocta agouti (agouti), and 22 Calomys callosus (vesper mice) were inoculated with infective eggs of Lagochilascaris minor. The inoculum was prepared with embryonated eggs and orally administered to each individual animal through an esophagus probe. In parallel, 100 specimens of Felis catus domesticus were individually fed with 55-70 nodules containing 3rd-stage larvae encysted in tissues of infected rodents. Animals were examined and necropsied at different time intervals. The migration and encystment of L3 larva was observed in viscera, skeletal muscle, adipose and subcutaneous tissues from all rodents. Adult worms localized at abscesses in the cervical region, rhino, and oropharynx were recovered from domestic cats inoculated with infected rodent tissues. Through this study we can conclude that: (1) wild rodents act as intermediate hosts, characterizing this ascarid heteroxenic cycle; (2) in natural conditions rodents could possibly act as either intermediate hosts or paratenic hosts of Lagochilascaris minor; (3) despite the occurrence of an auto-infecting cycle, in prime-infection of felines (definite hosts) the cycle is only completed when intermediate hosts are provided; and (4) in the wild, rodents could serve as a source of infection for humans as they are frequently used as food in regions with the highest incidence of human lagochilascariasis.
Resumo:
The morphology of Trypanosoma cruzi is reviewed since the initial description of Giemsa-stained preparations by Carlos Chagas until the most recent micrographs obtained with freeze-fracture techniques. Special emphasis is given to structures such as the cell surface, the flagellum, the kinetoplast, the reservosomes and the endocytic pathway, and the acidocalcisomes.
Resumo:
Allocreadium lobatum Wallin, 1909 has been reported in cyprinid species of freshwater fish in Canada and in the United States. The population biology of A. lobatum in the host Semotilus atromaculatus Mitchill was studied from May through December 1991, in a USA creek. Overall prevalence (64%) and mean intensity (4.4 ± 0.4) were greater than previously reported while abundance, reported for the first time, was 2.8 ± 0.3. Several trends in A. lobatum population biology as a function of S. atromaculatus length were identified. Mean intensity and abundance of A. lobatum increased with host size and significant differences in prevalence and A. lobatum lengths were found to correlate with host lengths.
Resumo:
The sporogony of Hepatozoon caimani has been studied, by light microscopy, in the mosquito Culex fatigans fed on specimens of the caiman Caiman c. crocodilus showing gametocytes in their peripheral blood. Sporonts iniciate development in the space between the epithelium of the insect gut and the elastic membrane covering the haemocoele surface of the stomach. Sporulating oocysts are clustered on the gut, still invested by the gut surface membrane. Fully mature oocysts were first seen 21 days after the blood-meal. No sporogonic stages were found in some unidentified leeches fed on an infected caiman, up to 30 days following the blood-meal. When mosquitoes containing mature oocysts were fed to frogs (Leptodactylus fuscus and Rana catesbeiana), cysts containing cystozoites developed in the internal organs, principally the liver. Feeding these frogs to farm-bred caimans resulted in the appearance of gametocytes in their peripheral blood at some time between 59 and 79 days later, and the development of tissue cysts in the liver, spleen, lungs and kidneys. Transmission of the parasite was also obtained by feeding young caimans with infected mosquitoes and it is suggested that both methods occur in nature. The finding of similar cysts containing cystozoites in the semi-aquatic lizard Neusticurus bicarinatus, experimentally fed with infected C. fatigans, suggests that other secondary hosts may be involved.
Resumo:
In the course of several trips to Peru I had the opportunity of collecting topotypic specimens of Biomphalaria andecola (Orbigny, 1835), B. helophila (Orbigny, 1835), B. pucaraensis (Preston, 1909), Drepanotrema limayanum (Lesson, 1830), D. kermatoides (Orbigny, 1835), and Lymnaea viatrix Orbigny, 1835, besides B. tenagophila (Orbigny, 1835), Helisoma trivolvis (Say, 1817), H. duryi (Wetherby, 1879), Physa acuta Draparnaud, 1801, and seemingly P. peruviana Gray, 1828. B. pucaraensis is considered a junior synonym of B. peregrina (Orbigny, 1835).
Resumo:
Kanaima Distant, 1909: description of a new species (Hemiptera, Auchenorrhyncha, Cercopidae, Tomaspidinae). A new species, Kanaima dubia, is described from São José dos Pinhais, Paraná, Brazil. It is similar, in general aspect, to Kanaima fluvialis (Lallemand, 1924).
Resumo:
The larva of Popanomyia femoralis and puparium of Engicerus major are described. The larvae were collected under the bark of fallen trees in an area near the tropical rain forest at Ilha da Marambaia (23º 04'15''S-43º53'59''W-sea level) and Cabo Frio (22º52'46''S-42º01'07''W-4 m), State of Rio de Janeiro, Brazil. Biological notes are presented. The larva of Popanomyia femoralis and puparium of Engicerus major are compared with those of Chalcidomorphina aurata Enderlein, Cosmariomyia argyrosticta Kertész, Dactylodeictes lopesi Lindner and Vittiger schnusei Kertész, other species of the same subfamily.
Resumo:
This work aimed to investigate the ratio of colonization by terrestrial mites on ice-free areas created by the ongoing climate-induced melting of Antarctic glaciers. Glacier retreat opens new ice-free areas for the colonization by vegetation and animals. The study was undertaken on the Antarctic Specially Protected Area no. 128 (West Coast of the Admiralty Bay, King George Island, South Shetlands Islands). Transects marked between the Ecology, Baranowski and Windy Glaciers, and a sea shore were used to collect soil samples. Oribatid mites were found only on near-shore areas, on patches of vegetation of more than 30 years of age. The colonization by mite communities is strongly determined by the presence of plants.
Resumo:
A lagarta-das-fruteiras, Argyrotaenia sphaleropa (Meyrick, 1909) (Lepidoptera: Tortricidae), é uma espécie freqüentemente encontrada danificando a cultura da videira e outras frutíferas de clima temperado na região Sul do Brasil e no Uruguai. Estudou-se a flutuação populacional de A. sphaleropa na cultura da videira com emprego do feromônio sexual sintético. Com base na avaliação semanal de machos de A. sphaleropa capturados em armadilha Delta contendo o feromônio sexual sintético (Z11,13-14Ac + Z11,13-14Al + Z11-14Al na proporção 4:4:1, impregnada em liberadores de borracha na dose de 1.000µg/septo), durante a safra 2003-2004, foram observados quatro picos populacionais na cultura da videira cultivar Cabernet Sauvignon. O primeiro pico populacional ocorreu no início do mês de outubro, o segundo no início de fevereiro, o terceiro teve o acme em meados do mês de março e o quarto no mês de junho. A temperatura média diária e a precipitação pluviométrica não exerceram influência sobre a captura dos insetos nas armadilhas. As informações deste trabalho permitem direcionar as táticas de controle para os períodos em que a população do inseto é mais elevada nos parreirais.
Resumo:
The word gas was coined by the "chemical philosopher" Joan Baptista Van Helmont (1579 -- 1644) to name a very broad concept in his chemico-medical system. Eventually, some physicians who followed Helmontian ideas adopted the concept. The present paper aims to analyze the reception of the original idea of gas by an English Helmontian physician, George Thomson (1619 -- 1677). Thomson wrote that the "material cause" of the plague was a gas, and compared it to the "Gas of sulphur". He also related the human archeus to a gas, and explained some observations in the laboratory in terms of production of gases. We observe, however, that Thomson was not as interested as Van Helmont in discussing details about the structure of the matter. Thus, gas did not have the same relevance in Thomson's work as it had in Van Helmont's.
Resumo:
The antimicrobial, hemagglutinating and toxic activities of the purple fluid of the sea hare Aplysia dactylomela are described. Intact or dialyzed purple fluid inhibited the growth of species of Gram-positive and Gram-negative bacteria and the action was not bactericidal but bacteriostatic. The active factor or factors were heat labile and sensitive to extreme pH values. The fluid preferentially agglutinated rabbit erythrocytes and, to a lesser extent, human blood cells, and this activity was inhibited by the glycoprotein fetuin, a fact suggesting the presence of a lectin. The fluid was also toxic to brine shrimp nauplii (LD50 141.25 µg protein/ml) and to mice injected intraperitoneally (LD50 201.8 ± 8.6 mg protein/kg), in a dose-dependent fashion. These toxic activities were abolished when the fluid was heated. Taken together, the data suggest that the activities of the purple fluid are due primarily to substance(s) of a protein nature which may be involved in the chemical defense mechanism of this sea hare.