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Biomedical subjects

F Superti

Publications and source records attributed to F Superti.

At least 55 records · Page 3Linked to original sources
PubMed1987

The effect of lipophilic amines on the growth of hepatitis A virus in Frp/3 cells.

The effect of lipophilic amines on hepatitis A virus infection in a monkey cell line (Frp/3 cells) was studied. Ammonium chloride, amantadine, methylamine and dansylcadaverine inhibited viral antigen synthesis when added to the cells at least one hour after the attachment step. Results obtained suggest that the HAV entry pathway in Frp/3 cells follows an endocytic route and that viral uncoating takes probably place in endosomes and/or lysosomes.

Amantadine↗
PubMed1987

Entry pathway of vesicular stomatitis virus into different host cells.

A biochemical and morphological investigation of the mechanism of entry of vesicular stomatitis virus (VSV) into host cells of mammalian (HeLa), avian (CER), piscine (EPC) and arthropod (Aedes albopictus) origin, is described. VSV was capable of infecting all cell lines tested by a endosome- and/or a lysosome-dependent step since ammonium chloride and amantadine blocked the early stages of infection. Complement-dependent immune lysis of infected host cells provided evidence that in none of the four different cell types examined did insertion of VSV antigens occur from the outside to any great extent on the cell surface. When the entry process was studied by electron microscopy, virus particles were seen to be bound to the cell surface at 0 degrees C. After warming at 37 degrees C for homeothermic cells or at 26 degrees C for poikilothermic cells, virus was detected within coated pits and coated vesicles and, later, in lysosomes. VSV entry was seen to take place by endocytosis in all four cell lines, which were derived from phylogenetically unrelated species.

Aedes↗
PubMed1987

Adhesive properties of Pseudomonas aeruginosa isolated from urinary tract infections.

A research was carried out on the adhesive properties of 104 uropathogenic strains of P. aeruginosa. On the basis of the adhesiveness to various types of cell it was possible to identify the most frequent adhesive patterns. Moreover, the ability of some carbohydrates to inhibit the adhesiveness of P. aeruginosa and the effect of some enzymes on the agglutinability of human erythrocytes by non-hemagglutinating bacterial strains was studied.

Agglutination Tests↗
PubMed1986

Involvement of gangliosides in rabies virus infection.

The role of gangliosides in rabies virus infection of chick embryo-related (CER) cells was investigated. Cultured cells were pretreated with neuraminidase to render the cells transiently non-susceptible to viral infection. Incubation of these desialylated cells with gangliosides allowed them to incorporate exogenous gangliosides and they recovered their susceptibility to rabies virus infection. Infection of CER cells was monitored by specific fluorescence 24 h after virus inoculation. The use of individual purified gangliosides or mixtures of two gangliosides to restore cellular susceptibility to viral infection showed that GT1b and GQ1b were the most effective. The disialogangliosides were also active, principally GD1b, whereas GM1, GM3 were poorly active and GD3 inactive. Incubation of rabies virus with gangliosides prior to virus infection reduced the percentage of infected cells. The results indicate that highly sialylated gangliosides are part of the cellular membrane receptor structure for the attachment of infective rabies virus. However, it is possible that other glycoconjugates such as glycoproteins or glycolipids also participate as components of a receptor structure for rabies virus.

Animals↗
PubMed1986

Membrane carbohydrate requirement for rabies virus binding to chicken embryo related cells.

The involvement of cellular carbohydrates in the interaction of rabies virus with chicken embryo related cell receptors was investigated. Two different methodological approaches were employed: specific glycosidases were used to treat the cells before infection, and specific lectins were used to compete with the viral binding. The results indicate the participation of sialic acid, galactose, mannose, and N-acetyl-glucosamine but not fucose in the cellular requirements for rabies virus infection.

Animals↗
PubMed1986

Role of sialic acid in cell receptors for vesicular stomatitis virus.

The role of sialic acid in the receptors for vesicular stomatitis virus (VSV) was investigated by treating chick embryo related (CER) cells and goose erythrocytes with neuraminidases from different sources and studying the effects produced on both infection and haemagglutination. The virus attachment to CER cells was reduced by their treatment with C. perfringens and A. ureafaciens neuraminidases and the susceptibility to viral infection of desialylated CER cells was recovered by coating with gangliosides immediately after enzymatic treatment. By contrast, enzymatic treatment of goose erythrocytes enhanced their agglutinability by VSV. The experiments carried out to test the ability of sialoglycolipids (gangliosides) and asialoglycolipids (cerebrosides) to inhibit virus attachment to CER cells or to goose erythrocytes showed that only gangliosides were able to inhibit VSV infection and haemagglutination.

Animals↗
PubMed1986

Study of receptors for vesicular stomatitis virus in vertebrate and invertebrate cells.

Early interactions between vesicular stomatitis virus (VSV) and susceptible cells were examined in cell lines of mammalian (HeLa), bird (CER), piscine (EPC) and arthropod (Aedes albopictus) origin showing different permissiveness to VSV growth. The chemical nature of receptors was investigated either by modification of cell surfaces with different enzymes or by competition for VSV binding between extracted membrane components and whole cells. Results obtained indicate that in all cell models, membrane lipid components show receptor activity whereas glycid groups participate to the in virus binding to a different extent.

Aedes↗
PubMed1985

E. coli adherence to CER cells infected by vesicular stomatitis virus.

Research was carried out on the adherence of a mannose-resistant uropathogenic E. coli strain to CER cells infected with vesicular stomatitis virus (vsv). A decrease in the bacterial adhesion was noticed during the early phases of viral infection, probably due to a close relationship between cell receptors for VSV and E. coli, both containing glycolipids and phospholipids. In a later phase of viral infection, on the contrary, corresponding to the appearance on the cell surface of newly synthesized viral antigens, bacterial adherence was enhanced. This last observation suggested a possible predisposition of the host to bacterial colonization during renal viral infection.

Adhesiveness↗
PubMed1985

Gangliosides in early interactions between vesicular stomatitis virus and CER cells.

In the present report an attempt was made to elucidate the role of gangliosides in early interactions between vesicular stomatitis virus (VSV) and CER cells. Research was carried out to test the ability of gangliosides from mammal brains and from CER cells to inhibit viral attachment to susceptible cells. The incubation of VSV in the presence of gangliosides decreased the subsequent infection of CER cells by the virus. When similar experiments were performed with gangliosides inserted in liposomes the inhibition of infection was enhanced. Since carbohydrate moieties could participate to rhabdovirus binding as a part of a glycolipid receptor, CER cells were subjected to the action of glycosidases and these produced a fall in the viral attachment. Deglycosilated CER cells reacquired their susceptibility to virus infection after coating with gangliosides immediately after enzyme treatment. Results obtained show the participation of gangliosides in the receptorial structure for vesiculovirus of susceptible CER cells.

Animals↗
PubMed1985

Effect of amantadine on rhabdovirus infection.

Enveloped viruses enter host cells by fusion or viropexis. The latter mechanism is the prevalent entry pathway of rhabdoviruses into susceptible cells. Amantadine, a lysosomotropic agent, inhibits the multiplication of various groups of viruses. The effect of this drug was investigated on vesicular stomatitis virus and rabies fixed virus strain replication in fibroblasts. Amantadine was added to cells before, during and after infection to detect the phase of viral replication affected by the drug. Cells were inoculated with viruses at 4 degrees C and the incubation temperature was progressively raised to 37 degrees C in order to observe the effect of amantadine on attachment and early stages of viral replication. Experimental results indicated that the compound inhibited rhabdovirus infection in CER cells. Viral attachment and penetration did not appear to be affected by the drug, while later steps were inhibited, probably at the level of uncoating when the virus is released from the lysosomes into the intracytoplasmic compartment.

Amantadine↗
PubMed1984

Role of phospholipids in rhabdovirus attachment to CER cells. Brief report.

The effect of phospholipases on rhabdovirus attachment to CER cells and the competitive binding of phospholipids and viruses to cells were studied. Results obtained indicate that, although to a different extent, some phospholipids represent a binding site for both Vesicular Stomatitis Virus (VSV) and rabies virus.

Animals↗
PubMed1984

Mechanism of rabies virus entry into CER cells.

The early steps of rabies virus (CVS) infection in vitro were studied in chicken embryo-related (CER) cells. The infection was monitored by looking for specific intracytoplasmic viral inclusions using anti-rabies fluorescein isothiocyanate at 24 h after the addition of virus. The attachment of rabies virus to CER cells was shown to be inhibited by pretreatment of the cells with neuraminidase. These cells recovered their susceptibility to rabies virus infection 6 h after removal of the enzyme. Treatment of CER cells with neuraminidase after the viral attachment step did not inhibit infection. The subsequent delivery of infectious virions into acid prelysosomal vacuoles or lysosomes was studied using lysosomotropic agents. Ammonium chloride and chloroquine were used to prevent the virus fusion step thus preventing infection. Both drugs were shown to inhibit the early steps of infection, NH4Cl having a much earlier effect than chloroquine. The two drugs had no effect on the attachment step nor did NH4Cl inhibit virus multiplication. The use of metabolic inhibitors (2-deoxy-D-glucose and sodium azide) shows that the entry of rabies virus into CER cells does not require the involvement of cellular energy processes. In electron microscopy studies, the presence of rabies virus particles was detected in coated pits and coated vesicles as well as in uncoated vesicles, and later in lysosomes. These data indicate that the mechanism by which rabies virus enters CER cells is probably through adsorptive endocytosis and does not require the participation of cellular metabolic active processes.

Adsorption↗
PubMed1983

Activity of human serum lipoproteins on the infectivity of rhabdoviruses.

The inhibiting activity of various human serum lipoprotein classes and their lipid components on the infectivity of rhabdoviruses has been studied. The research has been carried out according to different experimental procedures on both the vesicular stomatitis virus (Indiana strain), and the fixed rabies virus (CVS strain). The results obtained have shown an inhibition of the infectivity of VSV and CVS, mainly linked to the very low and low density lipoprotein classes. It has also been demonstrated that the inhibitors act directly on viruses causing a decrease in their attachment to host cells.

Humans↗
PubMed1982

Role of carbohydrates in cell membrane receptors for vesicular stomatitis virus.

A study has been made to clarify the importance of some carbohydrate components of goose red blood cell and BHK 21 cell membrane receptors for vesicular stomatitis virus (VSV). Experiments have been carried out by inducing enzymatic modifications on the surface of intact cells and following the interaction between VSV and treated cells. Results obtained indicate that the removal of mannose, galactose and fucose from cell membranes reduces the attachment of the virus to cell receptors.

Animals↗
PubMed1981

Receptors for BK virus on human erythrocytes.

The chemical nature of BK virus receptors on human erythrocytes was investigated. Glycosidases, KIO4, proteases, phospholipases and other substances acting specifically on different structures of plasma membranes were used to ascertain the role of surface cell components in the interaction with BK virus. The results obtained indicate an analogy between BK virus receptors on red cells and non-antibody serum inhibitors active against haemagglutination by the same virus.

BK Virus↗
PubMedDate not supplied

The rotavirus genus.

Human rotaviruses, discovered nearly 20 years ago, have been proven to be major cause of paediatric diarrhoeal disease morbidity and mortality. The clinical significance of these viruses stimulated basic studies on their biology, molecular and antigenic properties and epidemiology. General features, clinical relevance, epidemiologic pattern and laboratory diagnosis of human rotavirus infections are here reviewed.

Adult↗