Ebola virus can cause severe Ebola hemorrhagic fever. The mortality rate is 90 percent. Up till now, there is no effective vaccine or treatment of Ebola virus infection. Relaed researches on Ebola virus have become a hot topic in virology. The understanding of molecular mechanisms of Ebola virus infection of cells are important for the development of vaccine and anti-virus drugs. Therefore, this review summarized the recent research progress on the mechanisms of Ebola virus infection.
Carrier Proteins ; physiology ; Ebolavirus ; pathogenicity ; Hemorrhagic Fever, Ebola ; etiology ; Humans ; Membrane Fusion ; Membrane Glycoproteins ; physiology ; Pinocytosis

Two Heptad repeat motifs (HR1 and HR2) from paramyxoviruses F protein could form thermostable heterodimers containing high alpha-helix while virus infected host cell. Following that the viral membrane and the host cell membrane were juxtaposed, which leads to membrane fusion. Mumps virus (MuV) is a member of the genus Rubulavirus in the family of Paramyxoviridae. MuV could use similar infection mechanism as well as other paramyxoviruses. In this study the HR1 and HR2 regions of MuV F protein were predicted by a computer program and expressed in E. coli with the GST fusion expression system. The GST fusion or GST-removed proteins were purified with Gluthathion Sepharose 4B Column. GST pull-down experiment suggested the interaction of HR1 and HR2 peptides, and analysis of gel filtration showed two peptides could form multimer, which indicates that the HR regions of MuV F protein may play an important role in virus fusion.
Membrane Fusion ; genetics ; Mumps virus ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; genetics ; isolation & purification ; Repetitive Sequences, Amino Acid ; Viral Fusion Proteins ; biosynthesis ; genetics ; isolation & purification

BACKGROUND: The purpose of this study was to investigate the ultrastructural relation of H. pylori and gastric epithelial cells in their adhesion. METHODS: Endoscopic biopsy of gastric antrum and body was performed from 15 patients (9 men, 6 women) with chronic gastritis. These specimens were processed and observed by transmission electron microscope (Hitachi H-600). RESULTS: On the basis of morphological appearances, the different types of adhesion of the organism with the epithelial cells were categorized as filamentous connection, adhesion pedestals, membrane fusion. Coccoid and intermediate forms were associated with filamentous connection whereas bacillary forms were associated with adhesion pedestals and membrane fusion. CONCLUSION: Various types of adhesion were associated with H. pylori and gastric epithelium. Further studies are needed to investigate biophysiologic influence to epithelial cells by ultrastructural relationship.(Korean J Med 60:16-21, 2001)
Biopsy ; Epithelial Cells* ; Epithelium ; Gastritis ; Helicobacter pylori* ; Helicobacter* ; Humans ; Male ; Membrane Fusion ; Microscopy, Electron ; Pyloric Antrum

Esophageal perforation is uncommon, however, due to the lack of serosa, inflammation spread is rapid and common to neighboring structures, causing mortality and morbidity. Initial symptoms for esophageal perforation have not been clarified, but when the diagnosis and proper treatment is delayed, its clinical course is fatal. Prompt recognition and proper treatment of esophageal perforation or rupture is mandatory. We report a case of 21-year-old man patient with esophageal perforation after anterior fusion of the cervical spine. Diagnosis was made by clinical suspicion and confirmed by esophagography and esophagoscopy. The patient was successfully treated by primary closure with good clinical course.
Diagnosis ; Esophageal Perforation* ; Esophagoscopy ; Humans ; Inflammation ; Mortality ; Rupture ; Serous Membrane ; Spinal Fusion* ; Spine ; Young Adult

We studied the construction of fusion protein TAT-RIG-I-GFP prokaryotic expression vector and verified the function of TAT in transmembrane delivery. First, four pairs of specific primers were designed, and the RIG-I gene of Mallard Duck (Anas platyrhynchos) was cloned. Then, the pET-TAT-RIG-I-GFP and pET-RIG-I-GFP prokaryotic expression vectors were constructed. Meanwhile, they were converted to E. coli BL21 (DE3), which were induced to be expressed after culture. After the purification of His-60 nickel affinity chromatography column and the identification of SDS-PAGE, the purified TAT-RIG-I-GFP and RIG-I-GFP proteins were incubated to DF-1 cells. Finally, fluorescence microscopy was used to observe whether the corresponding fluorescence was produced in DF-1 cells. The results showed that pET-TAT-RIG-I-GFP fusion with TAT showed obvious green fluorescence in DF-1 cells. However, the pET-RIG-I-GFP without TAT cannot display green fluorescence. This shows that TAT-fused protein have successfully delivered DF-1 cells and play a key role in transmembrane delivery. In conclusion, these results provide a solid material basis for further study of antiviral drugs in poultry.
Cell Membrane ; DNA Primers ; Escherichia coli ; Gene Expression ; Gene Products, tat ; Genetic Vectors ; Recombinant Fusion Proteins

CD55 Antigens ; Complement Activation ; Humans ; Membrane Cofactor Protein ; Pemphigoid, Bullous ; Recombinant Fusion Proteins

Measles virus is an enveloped virus with a non-segmented negative-sense RNA genome. Two envelope glycoproteins on the viral surface, namely hemagglutinin (H) and membrane fusion protein (F), are responsible for the virus entry into susceptible host cells. The specific interaction between H and its cellular receptors is a key step in successful virus infection, determining the infectivity and tissue tropism of the measles virus. Thus far, three H receptors have been identified, including the complement regulatory molecule CD46, the signaling lymphocyte activation molecule (SLAM) and the cell adhesion molecule Nectin-4. Here, we reviewed our molecular understanding on the recognition mechanism of these receptors by the viral H protein, aiming to promote future studies on antiviral drug design and measles virus-based oncolytic therapy.
Animals ; Antigens, CD ; metabolism ; Cell Adhesion Molecules ; metabolism ; Hemagglutinins, Viral ; metabolism ; Humans ; Measles virus ; pathogenicity ; physiology ; Membrane Cofactor Protein ; metabolism ; Membrane Fusion ; Membrane Fusion Proteins ; metabolism ; Receptors, Cell Surface ; metabolism ; Receptors, Virus ; metabolism ; Signaling Lymphocytic Activation Molecule Family Member 1

OBJECTIVETo observe the inhibitory effect of 1,2,6-Tri-O-galloyl-beta-D-glucopyranose (TGGP) from Balanophora japonica Makino on human immunodeficiency virus (HIV) entry into the host cells and explore the mechanisms.

METHODSTGGP was purified from Balanophora japonica Makino by n-hexane and ethyl acetate extraction and column chromatography. The inhibitory activity of TGGP on HIV gp41 six-helix bundle formation was measured with ELISA, N-PAGE and SE-HPLC, and the inhibitory effect of TGGP on HIV envelope grlycoprotein-induced cell-cell fusion was detected using a non-infectious cell-based assay.

RESULTSTGGP inhibited HIV gp41 six-helix bundle formation, with an IC50 of 1.37-/+0.19 microg/ml as determined by ELISA, and this activity was further confirmed by N-PAGE and SE-HPLC. TGGP at 25 microg/ml significantly inhibited syncytium formation between the effector (CHO-WT) and the target (MT-2) cells.

CONCLUSIONThe HIV transmembrane subunit gp41 mediates the entry of HIV into the target cells. TGGP can inhibit HIV fusion and entry into the target cells by inhibiting the formation of gp41 six-helix bundles, suggesting the potential of TGGP as a microbicide to prevent sexual transmission of HIV.

Anti-HIV Agents ; pharmacology ; Cell Membrane ; drug effects ; metabolism ; HIV Envelope Protein gp41 ; metabolism ; HIV Fusion Inhibitors ; pharmacology ; HIV-1 ; drug effects ; growth & development ; metabolism ; Humans ; Hydrolyzable Tannins ; pharmacology ; Membrane Fusion ; drug effects

To reveal the effects of disulfide bridges in rubella virus glycoprotein E1 on the membrane fusion activity, the recombinant plasmid pBSK-SPE2E1 and site-directed mutagenesis to mutate 11 cysteines individually in the ectodomain of E1 to remove a disulfide bridge from the wild-type E1 were constructed. All mutants and the wild-type plasmid were expressed on BHK-21 cell. Giemsa Staining was used to show the polykaryon formed in the transfected BHK-21 cells. The cell surface expression efficiency of the plasmids was assayed with fluorescence-activated cell sorter (FACS). Hemadsorption was performed to detect the receptor recognition activity of the recombinant plasmids. The results showed that all the 10 disulfide bridges in the ectodomain of E1 played an important role in the process of the membrane fusion. The removal of any disulfide bridge resulted in the loss of the fusion activity. The disulfide formed by the 5th and the 8th cysteine might be critical for the interaction of E1 and E2. While the disulfide bridges formed by the 3rd, the 4th, and the 13th might influence the membrane fusion activity of E1 directly.
Cell Membrane ; drug effects ; Cysteine ; chemistry ; Disulfides ; chemistry ; pharmacology ; Flow Cytometry ; Membrane Fusion ; drug effects ; Mutagenesis, Site-Directed ; Rubella virus ; chemistry ; Viral Envelope Proteins ; chemistry ; Viral Fusion Proteins ; Virus Internalization ; drug effects

The fusion between liposome-liposome, liposome-biomembarnes induced by acid-sensitive polymers has been systematically investigated. The polymer-liposomes were constructed by post-insertion method with the poly (2-ethylacrylic acid) (PEAA) alkylamide derivatives. The liposomal fusion was studied by use of fluorescence resonance energy transfer assay, particle size, fluorescent-photometer. The results indicated that the poly (2-ethylacrylic acid)-liposomes has very strong acidic induced fusion capability. Under acidic conditions, acid-sensitive polymer liposomes fused each other, the fusion closely related to the molecular weight of acid sensitivity polymer on the surface of liposomes. The acidic fusion of polymer-liposomes was dependent upon the lipids composition, the degree of fusion was reversely related to the cholesterol contents. Acid-en ci-nsitive polymer liposomes fused with erythrocyte ghosts. The liposomal fusion induced by acid-sensitive polymer associated with the increase of membrane permeability. The good acid-sensitivity of PEAA has been further demonstrated by membrane fusion in current experiments, and the liposomes prepared with lipid anchored-poly (2-ethylacrylic acid) were developeds s a potential pH sensitive delivery system.
Acrylates ; chemistry ; Alkylation ; Drug Carriers ; Drug Delivery Systems ; Erythrocyte Membrane ; metabolism ; Humans ; Hydrogen-Ion Concentration ; Lipids ; chemistry ; Liposomes ; chemistry ; Membrane Fusion ; Molecular Weight ; Particle Size ; Polymers ; Temperature