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At least 937 records · Page 52Linked to original sources
PubMed1980

The discovery of Besnoitia wallacei in Australia and the identification of a free-living intermediate host.

A cat fed free-living rats (Rattus norvegicus and Rattus rattus) passed coccidian oocysts 14 days after eating a R. norvegicus. These oocysts were morphologically similar to B. wallacei and rats and mice dosed orally and intraperitoneally with them developed Besnoitia cysts in various body tissues. This organism was shown to have an obligatory two-host cycle and it is considered to be B. wallacei. This represents the first recorded detection of B. wallacei in Australia and also the first record of a natural free-living intermediate host for B. wallacei.

Animals↗
PubMed1981

The fine structural relationship between Theileria schizonts and infected bovine lymphoblasts from cultures.

The fine structure of Theileria-lymphoblast relationship was studied using cultured bovine lymphoblastoid cells infected with Theileria parva, T lawrencei, or T. annulata. The major findings of this study were: (1) the presence of a very active Golgi complex with the associated annulate lamelae; (b) the presence of cytoplasmic microtubules which joined the parasites and host cell centriole during lymphoblast mitosis; and (c) the absence of morphological evidence to suggest that the host cell developed a reaction to the parasitic presence. The significance of these findings is discussed.

Animals↗
PubMed1980

[Electron microscope investigation of the evolutionary stages of the trophozoite of Didymophyes gigantea (Sporozoa, Gregarinida). III. The fine structure of the epicyte with emphasis on the contractile elements (author's transl)].

The fine structure of the epicyte of D. gigantea was investigated. The motility of the gregarine and the contractile elements are described. Four essential types of movements can be observed in this gregarine: (1) rolling up and pendular movements, (2) locomotion by gliding forward, (3) cytoplasmic streaming (Fig. 1), (4) peristaltic contractions (Fig. 2) which seem to be accompanied by the contraction of annular myonemes (Fig. 2). The epicyte is formed by the folding of the parasitic cell wall which is made from three membranes (Figs. 3 and 4). At the top of each fold one can see apical struts between the outer and middle membrane and apical filaments under the inner membrane (Fig. 3). In addition, the epicytic folds are covered by a cell coat which is made from tubular structures (Fig. 5). At the base of the epicytic folds can be observed the basal lamina (Fig. 3) composed of very fine fibrillar material with an average thickness of 2.5 nm (Fig. 6). These fibrils are oriented in the longitudinal axis of the gregarine. Beneath the epicytic fold in the ectoplasm are found the annular myonemes with a width of up to 0.5 micrometers (Fig. 7). They are composed of many fine fibrils with an average thickness of 5 nm. In young trophozoites, the myonemes also contain microtubuli (Fig. 8). Between the epicytic folds, the cell wall is interrupted by three different types of vesicles: the vesicles with an electrondense content (Fig. 9), the three-membranous vesicles (Fig. 10), and the hose-shaped vesicles (Fig. 11). Glycerol-extraction of the parasites was performed in order to define the contractile structures. After extraction the annular myonemes are difficult to recognize (Fig. 13). When ATP is added, the gregarine does not contract but the myonemes reappear after 3 to 4 min (Fig. 14). Differences can also be observed in the myoneme structure using electron microscopy: After extraction, the myonemes are composed of a very limp fibrillar network (Fig. 15) which becomes very dense after the action of ATP (Fig. 16). Glycerol extraction does not disturb either the apical struts and apical filaments or the fibrils of the basal lamina (Figs. 15--17). In addition, cytoplasmic fibrillar structures appear after glycerol extraction (Figs. 15 and 16). The experimental and electron microscope results indicate that the motility of the gregarine depends upon four different systems: (1) the ectoplasmic annular myonemes, (2) the apical structures in the undulating epicytic folds, (3) the cytoplasmic fibrils, and (4) the basal lamina.

Animals↗
PubMed1984

Besnoitia sp. from goats in Kenya.

The eyelids of goats in Kenya contained several, conspicuous white cysts which were up to 1.5 mm in size. By histological and electron microscopical studies it was confirmed that these cysts belong to the genus Besnoitia.

Animals↗
PubMed1984

Two types of globidium-cysts of goats.

In the abomasum of naturally infected goats two types of globidium were found. An electron microscopic study revealed that the parasites were different from those described from sheep in former publications.

Abomasum↗
PubMed1984

Experimental studies on the interaction between infections of Ostertagia leptospicularis and other bovine Ostertagia species.

Experimental infections of calves were carried out with either isolates of predominantly Ostertagia ostertagi, pure O. leptospicularis or a mixed isolate of equal numbers of both these species. The total worms established on day 21 for the mixed species from a total inoculum of 100 000 infective larvae, was 1.2 times greater than from 100 000 larvae of the O. ostertagi isolate and 3.3 times that of the pure O. leptospicularis isolate. The increased establishment in the mixed inoculum referred to both O. ostertagi and O. leptospicularis (days 17 and 21). These differences were both highly significant (P less than 0.01). The severity of the pathological changes was also greater in the mixed infections. It is suggested that these findings must be taken into account when control measures involving alternate grazing of sheep and cattle are being employed.

Abomasum↗
PubMed1981

The ultrastructure of Encephalitozoon cuniculi growing in renal tubules of rabbits.

A wild type rabbit infected orally with cell culture-grown Encephalitozoon cuniculi. Twelve weeks after infection the rabbit was killed and blocks of kidney tissue were fixed for histology and electron microscopy. E. cuniculi were observed within kidney collecting tubule cells. The ultrastructure and development of E. cuniculi in these cells was similar to that described in cultured cells and peritoneal macrophages.

Animals↗
PubMed1986

The infectivity of Encephalitozoon cuniculi in vivo and in vitro.

The infectivity of Encephalitozoon cuniculi grown in cell cultures was determined in cultured cells and in wild and domestic rabbits. The ratio of the total to tissue culture viable count was 1,300 (median of seven determinations). The mean ratio of intact spore count to total count, as determined by electron microscopy was 0.12. Although variation between infectivity experiments was large, the median animal infective dose contained 51 FFU (cell culture focus-forming units) for wild rabbits (Oryctolagus cuniculus) and 40 FFU for domestic rabbits. These two infectivities were not statistically different.

Animals↗