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R Gestrich

Publications and source records attributed to R Gestrich.

17 recordsLinked to original sources
PubMed1975

[Light and electron microscope studies on cysts of Sarcocystis ovicanis Heydorn et al. (1975) within muscle fibres of sheep (author's transl)].

Four conventionally reared lambs, isolated at the age of 5 and 8 weeks, were orally infected with oocysts and sporocysts from dogs, which had been fed raw muscles from sheep containing small cysts of S. tenella. Three lambs, each infected with 100,000 sporocysts, were killed at days 41, 63 and 81 p.i. The other lamb was used for a non-infected control. The development of Sarcocystis-cysts in muscle cells of the infected lambs was studied by light and electron microscopy. The cyst was always situated within a muscle fiber which was never surrounded by fibrillar layers (=no secondary cyst wall). The cyst was limited by a unit membrane, which was thickened at numerous places of the interior by osmiophilic material. This complex is called primary cyst wall (= Primärhülle), reaching a thickness of up to 25 nm. In old cysts this primary wall was regulary folded, forming palisade-like protrusions of about 3.5 mu in length. In light microscopy the combined protrusions had the appearance of a radially striated "thick wall", because of their close proximity to each other. During formation of the palisade-like protrusions the thin areas of the primary wall were restricted to the base of the protrusions and to the small space between the protrusions. Here, the single unit membrane formed vesicle-like invaginations of about 40 nm in diameter into the interior of the cyst. Vesicles seen in the cysts were thought to derive from these invaginations. Within the palisade-like protrusions never fibrillar or tubular elements appeared. In comparing the fine structure of the cyst wall of the small cysts, studied here, with the macroscopically visible cysts we found significant differences. These differences in the morphology confirm the results of transmission experiments, by which it was shown that S. tenella as described in literature is part of at least two coccidian life cycles. So the term S. tenella was replaced by two new species: S. ovicanis (final host: dog) and S. ovifelis (final host: cat) Heydorn et al. (1975).

Animals↗
PubMed1975

[Light and electron microscope studies on cysts of sarcocystis fusiformis in the muscles of calves infected experimentally with oocysts and sporocysts of isospora hominis Railliet et Lucet, 1891. 1. The development of cyst and cyst wall (author's transl)].

In several experiments young calves were infected with isospora hominis sporocysts excreted by human males who had ingested raw beef containing Sarcocystis fusiformis cysts. On the 29th, 48th, 62nd and 98 day p.i. the calves were killed and the development of S. fusiformis cysts in muscle cells was studied by light and electron microscopy. Beginning with the 48th day p.i. numerous cysts containing small numbers of metrocytes only were observed. The cysts developed from a parasitophorous vacuole within the host cells. At first this parasitophorous vacuole was limited by a single unit membrane, which soon became thickened at numberous places inside of the vacuole by osmiophilic material. This complex is called primary wall (equal to Primärhülle), reaching a thickness of up to 32 nm in old cysts. This primary wall became regularly folded. forming palisade-like protrusions. On the 62nd day after inoculation these protrusions measured about 2-3 mum in length and 0.5-0.7 mum in diameter. In light microscopy the combined protrusions had the appearance of a radially striated "thick wall", because of their close proximity to each other.

Animals↗
PubMed1975

[Light and electron microscope studies on cysts of Sarcocystis fusiformis in the muscles of calves infected experimentally with oocysts and sporocysts of Isospora hominis Railliet et Lucet, 1891. 2. Fine structure of metrocytes and merozoites (author's transl)].

In several experiments calves were infected with sporocysts of Isospora hominis thus producing "thick-walled" cysts of Sarcocystis fusiformis in muscles. Following the growth of the cyst the development of the cyst stages (metrocytes, merozoites) was studied by electron microscopy. Cyst formation began about 40 days p.i. from a parasitophorous vacuole containing exclusively ovoid metrocytes. On the 62nd day p.i. mainly metrocytes and a few banana-shaped merozoites were present within the cysts, whereas on the 98th day p.i. only merozoites, i.e. infectious stages, were observed. The metrocytes were surrounded directly by the amorphous ground substance of the cyst's interior, but the merozoites were arranged relatively loose within chamber-like hollows of the ground substance. The metrocytes are globular cells, about 6-7 mum by 4. 5 mum. The typical three-layered pellicle had a few invaginations and several micropores, which seem to ingest numerous small vesicles from the interior of the cyst. These cells posses a conoid, polar ring with 22 anchored supellicular microtubules, several rhoptries and micronemes, a glogi complex anterior to the large nucleus. The nucleus has a spherical nucleolus consisting of granular and fibrillar zones. Chromosomal structres were seen in two different stages: large dense plaques (condensed stage), and as small dense granules of 300-400 a diameter, arranged sperically within the karyoplasm ( extended stage). The nuclear pores show the typical eight-fold symmetry known from other protozoa and numerous metazoa. The rought endoplasmic reticulum is very prominent within these cells as well as the tubular mitochondria...

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PubMed1975

[Light and electron microscope studies on cysts of Sarcocystis fusiformis in the muscles of calves infected experimentally with oocysts and sporocysts of the large form of Isospora bigemina from dogs. 1. The development of cysts and "cyst wall" (author's transl)].

In several experiments young calves were infected with Isospora bigemina (large form) sporocysts excreted by dogs which had been fed with raw beef containing Sarcocystis fusiformis cysts. On the 27th, 34th, 62nd, 76th and 150th day p.i. the calves were killed and the development of S. fusiformis cysts in muscles cells was studied by light and electron microscopy. On the 27th day p.i. in light microscope preparations numerous schizonts, merozoites and endodyogeny-stages were seen in various organs, such as the liver, lung, kidney, heart, small intestine, esophagus, skeletal muscles, diaphragm, cerebrum, and cerebellum. The merozoites measured 7-8 mug by 2-3 mum. Beginning with the 34th day p.i. numerous cysts containing small numbers of metrocytes only were observed in electron microscopy, too. The cysts developed from a parasitophorous vacuole within the host cells. At first this vacuole was limited by a single unit membrane, which soon became thickened byosmiophilic material at numerous places inside of the vacuole. This complex, called primary wall (= Primärhülle), reached a thickness of up to 200-250 A in all cysts. During growth of the cyst this primary wall became regularly folded forming alternating long and short club-shaped protrusions. The longer protrusions were about 0.6 mum long and 0.2-0.3 mum in diameter, whereas the short protrusions were of about 0.13 mum in length. In light microscopy the combined protrusions had the appearance of a very thin cyst wall because of their small size and their close proximity to each other. Later, all protrusions became longer with a maximum of about 3 mum in length without any change in the diameter. Yet, from the 76th day p.i. these protrusions appeared no longer straight, but they became folded over, following a course along the surface of the cyst. Evidently the protrusions did not increase in number after their initial formation, for the distance between them became greater in older cysts. No fibrillar elements were seen within these protrusions which probably accounts for the folding over. The zone of the superficial folded protrusions was not thicker than 1 mum so that in light microscope even the old cysts appeared as relatively thin walled. The interior of the original electron-pale parasitophorous vacuole bacame progressively condensed during the growth of the cyst. There was development of an amorphous ground substance, containing fine fibrils and granules. The ground substance became divided into thin speta (not visible with the light microscope) forming numerous changer-like hollows. The parasites were very closely packed within these hollows. At the beginning of the cyst formation only metrocytes were found within the young cysts, whereas on the 76th day p.i. and later only the infectious merozoites were present. It is therefore concluded that about 3 months after inoculation of calves with sporocysts of the large form I. bigemina from dogs the cysts are fully differentiated, thus being ready for a new transmission...

Animals↗
PubMed1975

[Light and electron microscopic studies on cysts of Sarcocystis fusiformis in the muscles of calves infected experimentally with oocytes and sporocysts of the large form of Isospora bigemina from dogs. 2. The fine structure of cyst stages].

In several experiments calves were infected with sporocytes of the large form of Isospora bigemina from dogs thus producing "thin-walled" cysts of Sarcocystis fusiformis in muscles. Following the growth of the cyst the development of the cyst stages (metrocytes, merozoites) was studied by electron microscopy. Cyst formation began about 34 days p.i. from a parasitophorus vacuole containing exclusively ovoid metrocytes. One the 62nd day p.i. mainly metrocytes and a few banana-shaped stages were present in the cysts. These banana-shaped stages were called merozoites, because we consider the process of cyst formation as an extraintestinal schizogony. From the 76th day p.i. mainly merozoites, i.e. infectious stages, were observed. The metrocytes were surrounded directly by the amorphous ground substance of the cyst's interior, whereas the merozoites were closely packed within chamber-like hollows of the ground substance. The metrocytes are globular cells, about 7 X 5 mum. These cells possess as the metrocytes of other species a typical three-layered pellicle with deep micropores, a conoid, polar ring with 22 anchored subpellicular microtubules, very few rhoptries and micronemes, a golgi complex anterior to the large nucleus. The nucleus has a spherical nucleolus consisting of granular and fibrillar zones. Chromosomal structures were seen in two different stages: large dense plaques (condensed stage), and as small dense granules of 300-400 A diameter, arranged spherically within the karyoplasm (extended stage). There is no significant difference in fine structure between the metrocytes of I. hominis-induced cysts and those from cysts after infections with the large form of I. bigemina from dog.

Animals↗
PubMed1975

[Light and electron microscope studies on cysts of Sarcocystis fusiformis in the muscles of calves infected experimentally with oocysts and sporocysts of the large form of Isospora bigemina from cats (author's transl)].

In several experiments young calves were infected with oocyss and sporocysts of the large form of isospora bigemina from cats, which has been fed by raw beef containing Sarcocystis fusiformis cysts. On he 98th and 160th day p.i. the calves were killed and the development of S. fusiformis cysts in muscle cells was sutided by lign and electron microscopy. The cyst was always situated within a muscle fiber which was never surrounded by fibrillar layers of host origin (= no secondary cyst wall). The cyst was limited by a singel unit membrane, which was thickened at numerous places of the interior by osmiophilic material. This complex is called primary wall (Primärhülle), reaching a thickness of up to 250 A. This primary wall was regulary folded, forming palisade-like protrusions...

Animals↗