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[Immuno-electron microscopy study of Toxoplasma gondii. II. Study of IgM antibodies].

This paper deals with an immunoelectron microscopic study of the localization of IgM vector on the membrane of Toxoplasma gondii using the antibody at the early period of infection. The primary antibody was IgM antibody obtained from rabbit's serum 11 days after the infection of Beverley strain of Toxoplasma gondii from which IgG was absorbed by protein A containing staphylococcus. Ferritine-labeled antibody against rabbit's IgM was used as the secondary antibody. The surface of normal tachyzoites is smooth with two layered plasma membrane. The outer layer shows a three-layer structure which is not found in the inner membrane. The inner membrane is discontinuous with partially lost portion at the head of the tachyzoites. Structure within plasma include conoid toxonems, dark staining vacuoles and nucleus. By reacting with the ferritin-labeled antibody, ferritin particles were found on all over the circumference of the tachyzoites depositing on the surface of the outer plasma membrane, but few on the inner plasma membrane and organelles. It implies that IgM receptors are localized on the membrane surface similarly with our preceding report.

Animals↗
PubMed1983

[Morphology of bacteria belonging to Propionibacterium genus in scanning and transmission electron microscopy].

Bacteria belonging to Propionibacterium genus reveal a characteristic shape of short rods. Their length is from 0.8 micrometer to 1.5 micrometer and their width reaches from 0.3 micrometer to 0.5 micrometer. Most bacteria of this genus have a constant ratio of cell length and their diameter is 2: 1. Their surface is smooth and has no cilia. Certain species of this genus, grown on liquid media, demonstrate the capacity of developing involution forms and of linking the cells into greater complexes which may appear in a form of flocculus. The characteristic feature, distinguishing this genus of bacteria from other ones, is that on their surface, the undefined scars and not-stated till now, structural formations were visible.

Culture Media↗
PubMed1983

Scanning electron microscopy and recording of the physiological activity of tracheal ciliated cells treated by fractionated irradiation.

The ciliated epithelium of the rabbit's trachea was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy. The beat frequency of the cilia was recorded and specimens were taken for SEM-, TEM- and LM-investigations. Examination was made 1-10 days after each fractionation schedule. An increased ciliary beat frequency was recorded at 2 Gy and 4 Gy. With increasing dose, there was an inverted relationship to the frequency. Light-microscopy showed edema and an increased amount of goblet cells in relation to the increasing dose. With SEM an increased number of ciliary blebs could be seen. These could be classified according to size and number, and showed a positive correlation to the dose. TEM-investigations showed signs of increased intracellular activity at higher doses in the form of multilobulated nuclei and an increasing number of nuclear pores. At lower doses, an increased amount of mitochondria appeared in the apical part of the cell. It is at present difficult to evaluate any correlation between the physiological activity and the morphology. More biological data are needed to explain the early irradiation effects.

Animals↗
PubMed1980

The effective osmotic pressure of the fixative for transmission and scanning electron microscopy.

In previous studies concerning the morphogenetic movements in the invaginating lens placode of the chick eye, a discrepancy between the TEM and SEM images was observed. With a fixation procedure giving good results in the TEM, certain changes seemed to have occurred in the SEM specimens (opening of apical cell blebs, bubble-like swelling of microvilli). These changes were suspected of being artefacts arisen during processing. Comparing SEM and TEM images of the invaginating lens placode and the surrounding surface applying two different osmolalities of the glutaraldehyde/formaldehyde fixative vehicle, and comparing SEM as well as TEM images with LM images of living embryos using differential interference contrast, yielded to following information. Recent reports in literature that ideal fixation techniques for SEM, certainly those preserving delicate surface structures as apical blebs and microvilli, can differ from those suitable for TEM, were confirmed. Apparently, the cell blebs which can be demonstrated in vivo to be closed, burst during SEM processing as a consequence of a relative hypo-osmolality of the fixative vehicle (a too low effective osmotic pressure). The TEM images appeared to suffer much less from changes in the osmolality of the fixative vehicle. It is suggested, therefore, that the artefacts are brought about by some step specific to the processing for the SEM (E.g. critical point drying).

Animals↗