Ultrastructural changes in murine liver following HSV infection and stroke

The study of herpetic infection is a topical problem. Although the peculiarities and consequences of acute HSV-I infection in the brain are quite well-studied, little is known about the damage to other organs which are not a source of latent HSV-I infection, the liver in particular. The current study is aimed at determining the ultrastructural changes in murine liver following HSV infection and stroke. Liver samples obtained from four groups of animals were studied: 1) intact mice; 2) mice with stroke; 3) mice infected with HSV-I; 4) mice aflicted with HSV-I and subsequently simulated stroke. The study showed the reproduction of the virus in hepatic endotheliocytes, although no virions were detected in the hepatocytes. Therefore, the described changes were considered the consequences of the infectious process. Pathological changes of hepatocytes consisted of deformation and fragmentation of the nuclei, as well as accumulation of osmiophilic granules, lysosomes and lamellary bodies. Latent HSV-I infection may reactivate in liver after the stroke, potentially causing the complications of the underlying disease.

Fine structure of lipotubuloids (elaioplasts) in Ornithogalum umbellatum L. I.

The bodies occurring in the ovary epidermis cells of <i>Ornithogalum umbellatum</i>, rich in lipids have been earlier described as elaioplasts. They consist of agglomerations of osmiophilic granules within the cytoplasm, caught in a network of, and interconnected by, a system of interesecting microtubules. These structures have been named lipotubuloids. They translocate in the cell by way of a progressive-rotary motion. Endoplasmic reticulum membranes, ribosomes and very scarse mitochondria and Golgi structures occur within the lipotubuloids.

Fine structure of lipotubuloids (elaioplasts) in Maha neglecta and Althaea rosea

The elaioplasts in the genus <i>Malva</i>, like those of <i>Ornithogalum umbellatum</i> are lipotubuloids, that means that they are aggregations of osmiophilic granules surrounded by a network of microtubules which in the lipotubuloids of Malva, are more labile than those of <i>Ornithogalum</i>.

Fine structure of lipotubuloids (elaioplasts) in Ornithogalum umbellatum in the course of their development

Among the most important changes in the fine structure of lipotubuloids, observed in the course of their development cycle, belong: 1) the appearance in ageing lipotubuloids of autolytic vacuoles, in which hydrolytic enzymes are present; 2) the disappearance of the microtubules forming a network and interconnecting the osmiophilic granules, which precedes the dispersion of these granules agglomerated in lipotubuloids.

Embryo sac development in Stellaria media

Osmiophilic granules were observed during certain stages of intermitotic periods in one, two and four nucleate embryo sacs in <em>Stellaria media</em>. The granules, some inside the short ER cisternae, were mainly distributed along the walls of nucleate embryo sacs. It is assumed that the osmiophilic granules may he involved in the deposition of substances within the wall of the megagametophyte.

Changes in Photosynthetic Characteristics and Antioxidative Protection in Male and Female Ginkgo during Natural Senescence

Ginkgo (Ginkgo biloba), a dioecious tree species, is widely distributed throughout the world, yet little is known about sex-related responses to autumnal senescence in ginkgo. The aim of this study was to investigate changes in photosynthetic activities, concentration of oxidative stress parameters [malondialdehyde (MDA) and H2O2] and antioxidant systems, and ultrastructure of chloroplasts in the naturally senescing leaves of two ginkgo sexes and to examine whether progression of senescence is sex-specific in ginkgo. Photosynthesis in ginkgo leaves of both sexes was not limited by stomatal factors, but rather non-stomatal factors such as decreased photosynthetic pigments and photochemical activities that became more important during autumnal senescence. The responses of antioxidative enzymes were different from those of antioxidants to leaf senescence. Correlation analysis revealed that autumnal leaf senescence was significantly correlated to antioxidative enzymes changes but not to antioxidants such as ascorbate (ASA) and glutathione (GSH). Guaiacol peroxidase (POD) became more important in senescing leaves and played a major protective role, especially at the late stage of senescence. The shape of chloroplasts of both sexes changed from oblong to round, and there was an increase in the number and size of osmiophilic granules during senescence; swollen thylakoid membranes in the stroma and grana with a significant increase in MDA content were also observed. During autumnal senescence, female ginkgo plants showed smaller decreases in net photosynthetic rates, photosynthetic pigments, photochemical activities, superoxide dismutase, ascorbate peroxidase and catalase activities, higher POD activity, ASA and GSH contents, and smaller increases in H2O2 and MDA contents than did males. In addition, female plants had a later senescence of chloroplasts, a smaller accumulation of osmiophilic granules, and a slower rate of membrane damage. These results show that female ginkgo exhibit slower leaf senescence, which may be related to increased reproductive costs.

Ultrastructure and Stereology of Leukocytes and Platelets of Normal Foxes and a Fox with a Chediak-Higashi-like Syndrome

Peripheral blood leukocytes and platelets from five normal foxes ( Vulpes vulpes) and a fox with phenotypical characteristics of Chediak-Higashi syndrome (CHS) were examined by electron microscopy. Lymphocytes, monocytes, neutrophils, eosinophils, and platelets from the affected fox contained giant membrane-bound granules that resembled lysosomes. In eosinophils and neutrophils from the affected fox and a normal fox, relative cell volume occupied by granules and number of granules per unit area were calculated. Relative cell volume occupied by granules was the same in both foxes, but there were significantly fewer granules per unit area in the affected fox. This result is consistent with the idea that the giant granules arose from fusion of pre-existing, normal-sized granules, as occurs in CHS. In platelets from the affected fox, no osmiophilic granules were seen. Our findings agree with those from studies of CHS-affected blood cells in other species.

The zoospore of Schizochytrium aggregatum

The zoospore ultrastructure of the marine protist Schizochytrium aggregatum was examined in detail. The zoospores of S. aggregatum differed considerably from the zoospores of the presumably closely related marine protist Thraustochytrium. The flagella of S. aggregatum emerged from an erumpent area and followed along shallow grooves on the spore body. The mastigonemes of the anterior flagellum are localized along one-third the circumference of the flagellar shaft. There is a concertina-like structure just distal to the kinetosome terminal plate and osmiophilic granules are present within the kinetosome lumen. Microtubular bundles are associated with the kinetosomes and form a "backbone root" system. Serial reconstructions show that each zoospore contains a single tubular mitochondrion. Closely associated with the mitochondrion is a single microbody which in turn is appressed to the nuclear membrane. The ultrastructural data suggest that Schizochytrium aggregatum can be accommodated among the Fungi.

Cytological studies on physodes in the vegetative cells of Cystoseira stricta Sauvageau (Phaeophyta, Fucales)

Physodes have been recognized in meristodermic and promeristematic cells by correlated light- and electron-microscope investigations using different fixation procedures. They are vesicles which contain an osmiophilic material of phenolic nature. Their content changes in appearence according to the fixative used. Osmiophilic deposits are often associated with coiled and disturbed lamellar formations. It has been possible to distinguish several ultrastructural stages which occur during the secretion of the content of the physodes, namely: a chloroplast accumulation and exudation, and a reticular transport to accumulation vacuoles where materials undergo evolution or hydrolysis. Inside plastids, osmiophilic granules are found in close association with thylakoid stacks. They may contain the polyphenolic precursors of physodes, though this has not yet been proved by electron-microscopy procedures. They are expelled from plastids to the chloroplast endoplasmic reticulum. The mechanism of transfer through the chloroplast envelope endoplasmic reticulum. The mechanism of transfer through the chloroplast envelope remains to be elucidated. Lytic activities have been reported inside physodes which might thus act in the same way as the secondary lysosomes of animals and higher plants. Occasionally, the physode content seems to be excreted from the cytoplasm to the cell walls by exocytosis after the probable fusion of plasmalemma and tonoplast. These cytological changes, observed in the vegetative apex of a brown alga, recall some ultrastructural characteristics of the secretory processes described in various glandular tissues of higher plants and which consist of the synthesis, the transport and the elimination of an exudate of flavonic, terpenic or lipophenolic nature.

The effect of crude oil on the morphology of the green flagellate Chlamydomonas angulosa

The morphological changes of Chlamydomonas angulosa induced by treatment with an aqueous crude oil extract (ACOE) have been studied and compared with normal cells in the exponential phase of growth. Observations of oil-treated cells under the light microscope showed an effect on flagellar length and on motility, an increased activity of the contractile vacuoles, and an increase in granulations. Cells so treated become surrounded by a transparent envelope. By electron microscopy, the progression of ultrastructural changes has been followed. These changes include: a widened space between the cell wall and the plasmalemma; distorted and disorganized chloroplast lamellae; a decrease in density of the osmiophilic granules; and the presence of electron-dense deposits inside the cytoplasmic vacuoles. Cells were found to possess the ability to recover from the above abnormalities within an 8-day incubation period. Such a recovery corresponds to resumption of motility, capacity for growth, and photosynthesis, as described in other work. Based both on appearance, and on comparisons with bacterial, fungal studies, and cytochemical studies, it is suggested that the osmiophilic granules are lipid in nature and may act as a hydrocarbon sink. A self-cleansing mechanism is also suggested for these granules.