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M Ozel

Publications and source records attributed to M Ozel.

At least 37 records · Page 2Linked to original sources
PubMed1990

Conserved epitopes of simian herpesvirus SA 8 and bovine herpesvirus type 2.

Some major structural components of simian herpesvirus SA 8 were analyzed and the relationship of SA 8 with HSV-1 and especially with BHV-2 was further characterized using a panel of SA 8- and BHV-2-specific monoclonal antibodies directed against gB, gD, gE, and ICP 8. It could be shown that SA 8 and BHV-2 expressed gB-1 equivalents, which differ in electrophoretic mobility, but share common epitopes with HSV-1. The antigenic determinants were detectable in the cytoplasm, on the surface of infected cells and on the virus envelope. Monoclonal antibodies reactive with epitopes of gB-SA 8 and gB-BHV-2 neutralized the homologous virus and cross-neutralized only HSV-1 and HSV-2, suggesting differences in accessibility of the corresponding epitope on SA 8 and BHV-2, respectively. A second protein with conserved epitopes on SA 8, BHV-2, and HSV-1 was identified as ICP 8. This nucleus associated protein was additionally detected on the envelope of SA 8 and HSV-1. The results imply that ICP 8 might have a function not only in virus replication, but also in virus assembly. We could furthermore define type-specific epitopes on two SA 8 envelope proteins which are analogous to gD-1 and gE-1, respectively. The gD-specific epitope induced a type-specific neutralizing antibody, making it interesting for differentiation of closely related herpesviruses.

Antibodies, Monoclonal↗
PubMed1990

Electron spectroscopic imaging (ESI) of viruses using thin-section and immunolabelling preparations.

Electron spectroscopic imaging (ESI) and conventional bright-field transmission electron microscopy (TEM) were applied comparatively for the analysis of the fine structure and the antigenic make-up of human immunodeficiency virus and two herpes viruses. In addition to the information obtained in conventional bright-field TEM, ESI leads to high-contrast imaging of ultrathin sections and improves the resolution of thin and thick sections, and allows a better detectability of the immunolabelling markers.

Antigens, Viral↗
PubMed1990

Characterization of immunostimulating complexes (ISCOMS) of HIV-1.

HIV-1, strain HTLV-III, propagated in H9 cells and purified by sucrose gradient centrifugation, was used as native antigen source for the preparation of immunostimulating complexes, HIV-iscoms. The major antigen detected in the iscom was the cell-derived HLA-DR, which readily could be removed from the virus lysate by immunosorbent. In the iscoms the HIV structural proteins MA p17, p55 and TM gp41 were identified; SU gp120 was present in only minute amounts in the virus lysate. The iscom particles appeared well preserved after freeze drying with a round shape, approximately 35 nm in diameter, comprising morphological subunits, assembled with icosahedral symmetry. Immunization experiments in mice reflected the antigen content of the iscoms. High antibody response was induced to HLA-DR in non-depleted iscoms. Major humoral responses were observed to the viral structural proteins MA p17, CA p24, p55, and also to TM gp41. A low or negligible antibody response to SU gp120 was induced by the HIV-iscoms. The negligible response was, however, overcome by the addition of recombinant gp160 to the virus lysate prior to formation of iscoms, resulting in a preparation evoking a clear serum antibody to gp160.

Animals↗
PubMed1990

Enterohemolysin production is associated with a temperate bacteriophage in Escherichia coli serogroup O26 strains.

A temperate bacteriophage that determines the expression of enterohemolysin was isolated from Escherichia coli O26 strain C3888. The genetic determinant associated with enterohemolysin production (E-Hly determinant) was cloned from EcoRI-digested bacteriophage DNA in vector plasmid pUC8. pUC8 recombinant plasmid pEO19 carries a 3.7-kb EcoRI insert of phage DNA, and enterohemolysin was expressed in E. coli K-12 after transformation. Hemolysin-negative derivatives of pEO19 were generated by transposon mutagenesis with Tn1725. By subcloning, the phage E-Hly determinant was assigned to a 2,150-bp piece of DNA which is flanked by EcoRI and AccI restriction sites. The enterohemolysin-producing recombinant strains and wild-type strain C3888 express a 60-kDa protein which was detected in the bacterial outer membrane by Western immunoblotting. Biologically active enterohemolysin was detected only in bacteria grown to the stationary phase, and the hemolysin was not released into the culture medium. Lysis of erythrocytes was inhibited by 30 mM dextran 4, which functions as an osmotic protectant without destroying the enterohemolysin itself.

Bacteriophages↗
PubMed1989

Morphogenesis and morphology of HIV. Structure-function relations.

Fine structure and antigenic make-up analysis of HIV were combined in a 2D model, from which functional aspects can be deduced. On the envelope 72 probably trimeric surface knobs (gp120) are connected to the virion via the transmembrane protein gp41. Gp120 is shed during ageing of the virion, but host cell antigens stay firmly anchored to the envelope. Underneath the envelope, p17 forms the matrix protein layer, while the capsid of the double cone shaped core is built up of p24. The relation between biochemical findings and morphogenesis and maturation of HIV as well as aspects of pathogenesis and vaccination are discussed.

Forecasting↗
PubMed1989

Quaternary structure of the immunostimulating complex (iscom).

Proteins of either HIV-1, hepatitis B, or rabies virus were incorporated with the adjuvant substance Quil A and cholesterol into the immunostimulating complex: iscom. Formation and symmetry of this regular complex were analyzed by electron microscopy. Micellar structures with a diameter of about 12 nm, occasionally with a 7-nm stain-filled center, were formed in a 0.03% water suspension of Quil A. Cavities or holes appeared in the smooth structures of cholesterol upon the addition of Quil A, and after mixing Quil A and cholesterol 1:1 fragile and flattened structures of matrix were produced with a diameter of about 40 nm. By freeze-drying the matrix was preserved as a cage-like, isometric particle. Stable iscom particles composed of Quil A, cholesterol, and selected viral proteins had an approximate diameter of 32 nm. The particles had an uniform, cage-like structure, exhibiting icosahedral symmetry, irrespective of the viral proteins incorporated. Tilting experiments and rotational image analysis indicated that the iscoms were composed of 20 morphological subunits assembled in a pentagonal dodecahedron with a hole on each of the 12 pentagonal faces. The symmetrical shape of the iscom might explain both its remarkable stability and its capacity to efficiently present antigens to the immune system.

Adjuvants, Immunologic↗
PubMed1988

Biomedical applications of chromatographic fraction containing trehalose dimycolate in squalane emulsion.

Trehalose dimycolate extracted from mycobacteria is a potent immunomodulator. Incorporation of trehalose dimycolate in a squalane-in-water emulsion leads predominantly to the formation of vesicular structures, which are observable by electron microscopy. The interaction between vesicles of trehalose dimycolate and the immunocompetent cells results in an enhancement of the host defence mechanisms and induction of non-specific resistance against viral, parasitic, and bacterial pathogens and certain tumors. A brief review of the pertinent observations is presented.

Adjuvants, Immunologic↗
PubMed1988

The organization of the envelope projections on the surface of HIV.

The organization of envelope projections (knobs) of four different isolates of the human immunodeficiency virus types 1 and 2 (HIV-1 and -2) was studied using surface replica and thin section electron microscopy (EM) in combination with rotational image enhancement. All HIV strains show an identical organization of knobs on the virus envelope. The surface of an "ideal", well-preserved HIV particle is studded with 72 knobs arranged in a T = 7 laevo symmetry. The role of the p 17 protein, which is coating the inner leaflet of the viral envelope, is discussed as a matrix protein functioning as a scaffold for the envelope and its projections during morphogenesis as well as with mature virions.

HIV↗
PubMed1987

Fine structure of human immunodeficiency virus (HIV) and immunolocalization of structural proteins.

Ultrathin section and surface replica electron microscopy were applied in combination with immunoelectron microscopy to elucidate the fine structure of HIV. The shell of the tubular core shows p24 antigenicity, while p17 is located at the inner leaflet of the lipid membrane. The virus particle is studded with 70-80 protrusions. These knobs have a diameter of 15 nm, a height of 9 nm, and are probably arranged in a T = 7 I symmetry. The major envelope protein gp120 is spontaneously shed from the viral surface. A possible role of released gp120 in pathogenesis is discussed.

Cell Line↗
PubMed1986

Lipophilic muramyl dipeptide-induced changes in electron microscopic morphology and phagocytic function of murine macrophages.

The capacity of a lipophilic derivative of synthetic muramyl dipeptide (MDP), B30-MDP, to induce morphological changes and functional alterations in the activity of resident peritoneal macrophages was studied. Macrophages incubated in vitro for 24 h with B30-MDP, but not with MDP or medium, showed rounding and extensive ruffling of the cell surface when examined by scanning electron microscopy. Transmission electron microscopy of B30-MDP-treated macrophages revealed the development of large cytoplasmic vacuoles. These structural changes did not affect the viability of macrophages. The Fc receptor-mediated phagocytosis of 51Cr-labeled sheep red blood cells by adherent macrophages incubated with a high dose of MDP showed a modest response whereas even low doses of B30-MDP greatly enhanced the phagocytic activity. Adherent macrophages incubated with B30-MDP generated elevated levels of luminol-dependent chemiluminescence in response to stimulation by zymosan.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1985

Capsid symmetry of viruses of the proposed Birnavirus group.

The capsid architecture of three members of the tentatively formed group of bisegmented ds RNA containing animal viruses (Birnavirus group) was studied in comparison with the fine structure of reovirus type 1 using high resolution negative staining and shadowing techniques followed by rotational enhancement analysis. IPNV of the trout, IBDV of the chicken, and eel virus (Berlin) are single-shelled particles with a capsid diameter of 61-65 nm and thus clearly distinguishable from the double-shelled reovirus being 80-85 nm in size. The capsid symmetries of both groups of viruses are skew, with a triangulation number T=13. The handedness of the capsid is dextro for IBDV and EV, and laevo for IPNV and reovirus type 1.

Animals↗
PubMed1984

Morphogenesis and fine structure of eel virus (Berlin), a member of the proposed Birnavirus group.

Eel Virus (Berlin) is associated with the occurrence of skin tumors in European eels. The genome of the virus consists of two segments of double-stranded (ds) RNA. The agent is assembled exclusively in the cytoplasm. Isometric particles with a diameter of 61 nm and in addition tubular structures and smaller particles were observed. The virion has a single shell: its capsid is composed of 132 interconnected morphological units with T = 13 dextro symmetry. According to particle size and bipartite nature of the genome, this virus has to be assigned to the tentatively proposed group of bisegmented ds RNA animal viruses.

Anguilla↗
PubMed1983

Characteristics of mastadenovirus h 8, the causative agent of epidemic keratoconjunctivitis.

Adenovirus 8 (Ad 8, strain 1127) has the general structural features of an adenovirus; it produces the genus-specific hexon antigen. The fiber length of 12 nm corresponds to that of other subgenus D adenoviruses. In hemagglutination-inhibition, Ad 8 is related to Ad9 and Ad 15/H9. The slow multiplication, compared to most other subgenus D viruses, was shown not to be caused by an extended growth cycle, but appears to be due to an inefficient virus release into the medium. After restriction analysis with the enzymes Sma I and Bgl II, the typical fragment patterns of species from subgenus D were obtained, while very different patterns emerged from the analysis with Hind III, Bam HI, and Bst E II endonucleases. Several strains of Ad 8 produced more penton-associated toxin than Ad 15/H9 used as reference virus from subgenus D, which could explain the "clumping CPE" caused by Ad 8. Ad 8 toxin was neutralized by antisera from many adenovirus species. The poor virus yield of Ad 8 was not improved by removing soluble viral or cellular substances; all other attempts to improve virus yield by varying the conditions of cell culture also failed.

Adenoviridae Infections↗
PubMed1982

The short- and long-term effects of bezafibrate in the rat.

Bezafibrate is a potent hypolipidemic agent, which causes marked proliferation of peroxisomes in rat liver. At the same dosage, bezafibrate is more effective in male than in female rats. This is probably related to divergent pharmacokinetics, which cause differences in drug level in serum and liver. The volume density of peroxisomes and several of their enzymes such as carnitine acetyl transferase and acyl-COA oxidase increase in a dose-related fashion. The hypolipidemic effect of bezafibrate, however, does not correlate with the used dosage. This implies that peroxisomal proliferation may play only a minor role in the hypolipidemic action of bezafibrate. In animals treated for 26 months with 300, 750, or 1500 ppm bezafibrate, the relative liver weight and serum triglycerides did not differ significantly from controls. Peroxisomal proliferation varied in different cells, being most prominent in single hepatocytes. The liver catalase activity was significantly reduced, but carnitine acetyl transferase was increased. Abnormal peroxisomes and mitochondria with longitudinal cristae were quite frequent. In one focus, catalase activity was severely diminished ahd peroxisomes were markedly reduced. The incidence of liver tumors was the same (1-3%) in treated animals as in controls.

Animals↗
PubMed1978

Effect of hexachlorobenzene and acetone on algal growth: physiology and ultrastructure.

The effect of hexachlorobenzene (HCB) and acetone on growth and ultrastructure of the freshwater alga Chlorella pyrenoidosa was studied. The algal cells were grown for 76 h under continuous light in 10 ppm HCB with 0.33% acetone or in 0.33% acetone alone; the control cells were grown in nutrient solution only. As was deduced from determinations of dry matter, carbohydrates, chlorophyll content and total nitrogen, 0.33% acetone in nutrient solution slightly decreased the growth of the cells without having any influence on their ultrastructure while 3.33% acetone affected the ultrastructure of the cells severely. An incubation of Chlorella with 10 ppm HCB in nutrient sultion containing 0.33% acetone led to a drastic decrease of all growth parameters studied, total nitrogen and chlorophyll content being affected most strongly. These latter observations were in accord with the changes in ultrastructure showing damage to the cell membranes, disintegrated cytoplasm and sometimes even break down of cell organells leaving only starch grains, the pyrenoid and some endomembranes. In addition to these cells with severe lesions, quite normal cells were found.

Acetone↗
PubMed1977

Biological and biophysical characteristics of mouse adenovirus, strain FL.

Mouse adenovirus, strain FL (MAV), is best propagated in primary rather than secondary cultures of mouse kidney cells. Virus release from the cells into the medium is fairly efficient; the average yield per cell is about 1000 TCID50. Morphological and other biophysical characteristics are those of a typical adenovirus: the icosahedral shell with a diameter of 74 nm, fiber projections of 29 nm length, its localization inside the infected kidney cells, a buoyant density in CsC1 of 1.34 g/ml, inhibition of multiplication by inhibitors of DNA synthesis. The thermostability is higher than that of human adenoviruses, whereas, in contrast to these, MAV is inactivated to a great extent by trypsin. Complete or incomplete hemagglutinin or toxin-like activity were not detected. The virus shows no cross-neutralization with human adenoviruses and a one-side cross-reaction with another murine adenovirus strain K-87. Soluble complement-fixing antigen of MAX exhibits a sedimentation rate of 12S identical to the hexon component of human adenoviruses; both antigens show a partial antigenic relationship in tests with appropriate antisera.

Adenoviridae↗
PubMed1975

[Comparative studies by the electron microscope of rhabdoviruses of plant and of animal origin. III. Egtved virus (VHS) of the rainbow trout (Salmo gairdneri) and rickettsia-like organisms (author's transl)].

With the exception of isolates from blood and homogenates of diseased fish, the presence of Egtved virus (=VHS, viral haemorrhagic septicemia of the rainbow trout) could not yet be demonstrated directly in host organs by electron microscopy, although recently, antigen has been identified in a number of organs by means of fluorescent microscopy. Demonstration of virus from organ extracts by means of a permanent cell culture from a coldblooded animal: Salmo gairdneri (RTG-2) as described in the present paper does not allow for a clear conclusion as to the presence of virus within organ cells. Egtved virus was studied in various organs (brain, heart, liver, kidneys, spleen, gills) of naturally and artificially infected trouts. Virus could not be demonstrated by electron microscopy in any of the organ sections. However, in RTG-2 cell cultures infected by organ extracts from naturally diseased trouts, a clear cytopathogenic effect could be observed in the 1st passage at + 15 degrees C after 48-72 hours and virus demonstrated by electron microscopy (Table, Figs. 1, 2, 3, 4). Both in organ sections (heart, kidney, spleen, and gills) from diseased trout and in RTG-2 cells infected with organ extracts, additional organisms were observed which on account of their ultrastructure could be classified as rickettsia (Table, Figs. 5, 6, 7, 8, 9). On account of the fact that these organisms were found in the organs of trout infected with Egtved virus and which partially died in great numbers, a pathogenic behaviour of these organisms is suggested. It has not yet been clarified whether they have any influence on the course of the viral infection or temporary mass dying of rainbow trout when kept in hatcheries.

Animals↗