Ultrastructure of the amoebo-flagellate Protonaegleria westphali.

Investigation of the ultrastructure of Protonaegleria westphali has been carried out by means of scanning electron microscopy (SEM) and transmission electronmicroscopy (TEM). SEM investigation demonstrated much enlarged trophozoites, flagellates and cysts corresponding to those under light microscopical observation. In situ fixation of moving trophozoites revealed attachment to the substratum by many uroidal and lateral filopodia. The typical flagellate stage has four flagella inserted two by two at the anterior pole of the cell. The smooth wall of cysts had prominent pores sealed by a mucous plug. Apart from their greater size, trophozoites and cysts resemble those of the genus Naegleria. Mitochondria are not as elongated as in the case of Naegleria; rather, they are round. The cyst is surrounded by a thick, layered endocyst (0.2-0.5 micron) and a delicate ecotcyst loosely apposed to the endocyst. Both walls join at the region of the prominent pores, forming a characteristically thick collar. This, together with the pore structure (up to 1.0 micron in diameter) places the amoeba in group I of N. gruberi, according to Pussard and Pons (1979). The flagellate state usually has four flagella which are anchored firmly by a prominent flagellar apparatus or mastigont at the anterior pole of the cell, comparable to that of the genus Tetramitus. The flagella show a typical 9 + 2 arrangement of microtubules (MT) and are surrounded by a sheath which is continuous with the cell membrane. Main elements of the mastigont could be demonstrated as typical kinetosomes of 0.75 micron length. Each is closely associated with the cross-striated rhizoplast located perpendicular to it.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural changes of Trichomonas vaginalis prior and after cryopreservation.

Fine structural changes of Trichomonas vaginalis are described prior and after the freezing process in liquid nitrogen. Dimethyl sulfoxide (DMSO) used as the cryoprotectant caused distinct alterations of the cytoplasm when trichomonads were equilibrated with 5% DMSO under various experimental conditions. Changes were bubble-like protrusions, fissuration and/or vacuolation of the cytoplasm, doubling and removal or/and rupture of the cell membrane. Apart from these findings cryopreservation caused marked alterations on the hydrogenosomes, such as condensation and flocculence of the usually homogeneous contents; in addition numerous hydrogenosomes fused while loosing membrane at the site of fusion. However, several parasites revealed normal hydrogenosomes after the freezing process. It is assumed that these organisms survived freezing and thawing as demonstrated by successful cultivation of recovered trichomonads.

[Fine-structure changes in Toxoplasma gondii trophozoites after deep-freezing with dimethyl sulphoxide (author's transl)]. / Feinstrukturelle Veränderungen von Toxoplasma gondii-Trophozoiten nach Tiefgefrierung mit Dimethylsulfoxid.

The changes observed in trophozoites of Toxoplasma gondii after deep-freeze preservation were examined by electron microscopy. Toxoplasmas (strain BK) from peritoneal exudate of infected NMRI mice were supended in Ringer's solution, deep-frozen in liquid nitrogen with 5% dimethylsulphoxide (DMSO), and compared after thawing with control samples with and without the addition of DMSO. Slight structural changes such as widening of endoplasmic reticulum, formation of fissures in the cytoplasm, and loosening of chromatin were only observed in some of the free toxoplasmas of the DMSO control. Among the deep-frozen parasites, about 1/5 of the free stages showed no or only slight morphological changes. In contrast to this, almost all intracellular forms found in macrophages showed lesions. The most remarkable change was a partial destruction of the inner cell membrane complex. The outflow of ribosome-containing protoplasm with ballon-like swelling of the outer elementary membrane was observed as a consequence of this frequent lesion. The outflow of protoplasm induced a drastic decrease in the electronic density of the whole cytoplasm. Other characteristic degenerative signs were vacuolation of cytoplasm up to formation of great optically empty spaces, widening of the perinuclear space, swelling of mitochondria, disintegration of rhoptria, micronemata, and Golgi zone, coarse-plaque loosening, and displacement of electron-dense areas of the nucleus up to disintegration with maintenance of the karyoplasm. In some almost completely disintegrated trophozoites, enlarged mitochondria with remarkable electronic density were observed. Apart from the cell membrane, the conoid was the longest-persisting organelle. The alterations observed after deep-freezing permit the conclusion that the free cells, which were only slightly impaired or not at all, remained infective.

[Invasion of erythrocytes by toxoplasma gondii (author's transl)]. / Invasion von Erythrozyten durch Toxoplasma gondii.

The in vitro-invasion of mouse erythrocytes by Toxoplasma gondii could be detected and analysed by electron microscopy. The sequence of events observed during erythrocyte invasion led to the assumption of an actively penetrating parasite into the non-phagocytic host cell.

Structural changes on Entamoeba histolytica trophozoites after cryopreservation in liquid nitrogen.

Trophozoites of Entamoeba histolytica cultures which had been deep-frozen in the presence of 5% DMSO, along with untreated cells and cells treated with DMSO (5%), were examined for fine-structural changes. After deep-freezing in liquid nitrogen only a few amoebae exhibited normal nuclear and cytoplasmic structure. One frequently observed but unspecific finding pertaining to recovered cells is the separation of the cytoplasm into large vacuolated (coarse-granular) and electron-optically fine-granular (hyaline) zones. The glycogen which normally lies in the cytoplasm is always eluted. In many cases numerous short RNP helices are scattered unevenly in the vesicular plasma, but they are also found in larger masses adjacent to the membranes of still intact and already damaged nuclei. Moderately damaged nuclei have a poorly folded membrane and their chromatin is markedly denatured. More heavily damaged nuclei have a membrane which has partly fibrillated or ruptured and then formed conspicuous folds, where the nuclear membrane has ruptured nucleoplasmic remnants of chromatin and button-like bodies appear to pour into the surrounding cytoplasm. The final destruction of the cell is marked by coalescing autolytic zones, first in the vacuolated and later in the fine-granular cytoplasm. Finally only remnants of the nuclear membrane and of the membranes of numerous vacuoles remain. It is assumed that most of the changes in the cytoplasm are of a secondary nature and are caused by the early functional disturbance of the nucleus.

[Fibrillar and tubular fine structures in the cytoplasm of Entamoeba histolytica (author's transl)]. / Fibrilläre und tubuläre Feinstrukturen im Cytoplasma von Entamoeba histolytica

The electron-microscopical study of conventional fixed and contrasted Entamoeba histolytica-trophozoites from Diamonds monoxenic TTY-medium revealed "thick fibrils" in the vesicular cytoplasm of the parasites. They are 9-14 nm in diameter and are therefore considered to be myosin-like filaments, that are spread mainly in the tail or the uroid of the moving ameba. No association with microfilaments (MF) or other organelles could be observed. During the same investigation microtubules (MT) of variable length are described having a diameter of 35 nm, surrounded by a 19-25 nm wide capsule. They are distributed singly or in bundles with a maximal diameter of 350 nm. Some of the MT were coiled up to a helical shape.

[Influence of antiphlogistics, antireheumatics, and acid mucopolysaccharides on in-vitro collagen fibril formation]. / Beeinflussung der Kollagenfibrillenbildung in vitro durch Antiphlogistika, Antirheumatika and saure Mukopolysaccharide

41 compounds, anti-inflammatory agents, acid mucopolysaccharides, and other substances were investigated in vitro for their ability to influence the formation of collagen fibrils. The acid anti-inflammatory agents accelerated the formation of collagen fibrils partially, acid mucopolysaccharides inhibited it. The results are discussed regarding the effects exhibited by anti-inflammatory agents and mucopolysaccharides in rheumatoid arthritis and osteo-arthrosis.

Diol lipids of rat liver. Quantitation and structural characteristics of neutral lipids and phospholipids derived from ethanediol, propanediols, and butanediols.

Specific enzymatic and chemical degradation of neutral lipid and phospholipid fractions from rat liver revealed the presence of novel types of lipid metabolites bearing a short-chain diol backbone. Diol-derived lecithin and cephalin analogs were readily cleaved by phospholipase C (EC 3.1.4.3) from Bacillus cereus, although the cephalin analogs required "carrier" lecithin to sustain hydrolysis. The products of phosphilipase hydrolyses as well as the neutral lipid fractions were subjected to alkaline and acidic methanolysis, and constituent short-chain diols were analyzed as long-chain cyclic acetals. Gas chromatographymass spectrometry confirmed that 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, and 1,3 butanediol can form the polyol backbone of neutral lipids and phospholipids. [1,1,2,2-2H]Ethanediol monohexadecanoate, dihexadecanoate, hexadecanoylphosphorylcholine, hexadecanoylphosphorylethanolamine were synthesized chemically and served as internal standards to assure accurate quantitation of the low levels of diol lipids (350 mug/g ot total lipid) present in rat liver.

Identification and quantitation of lipid-bound short-chain diols.

Procedures are described for the hydrolysis of neutral lipid fractions containing long-chain esters and alk-1-enyl ethers of short-chain diols, and for the identification and quantitation of the constituent diols as long-chain cyclic acetals using gas-liquid chromatography in combination with mass spectrometry.