Viruses others

Gene Therapies. The types of vectors that have been used or proposed for gene transduction include retrovirus, adenovirus, adeno-associated viruses, other viruses (e.g., herpes, vaccinia, etc.), and plasmid DNA. Methods for gene introduction include ex vivo replacement, drug delivery, marker studies, and others and in vivo, viral vectors, plasmid vectors, and vector producer cells. 

At the outset, recognize that there are many types of biological membranes some surround complex viruses others occupy a space inside the bacterial cell wall and still others isolate mammalian cells from their enviromnent. 

Antibodies against the virus but also amantadine and derivatives, interfere with host cell penetration. There are nucleoside analogues such as aciclovir and ganciclovir, which interfere with DNA synthesis, especially of herpes viruses. Others like zidovudine and didanosine, inhibit reverse transcriptase of retroviruses. Recently a number of non-nucleoside reverse transcriptase inhibitors was developed for the treatment of HIV infections. Foscarnet, a pyrophosphate analogue, inhibits both reverse transcriptase and DNA synthesis. Protease inhibitors, also developed for the treatment of HIV infections, are active during the fifth step of virus replication. They prevent viral replication by inhibiting the activity of HIV-1 protease, an enzyme used by the viruses to cleave nascent proteins for final assembly of new vi-rons. 

If all the sugar residues of the glycophorin molecules in an erythrocyte were spread over the surface of the cell they could cover approximately one-fifth of its surface in a loose network. However, it is more likely that they form bushy projections of a more localized sort. These oligosaccharides not only act as immunological determinants but also serve as receptors for influenza viruses. Other glycoproteins related to glycophorin A occur in smaller amounts.244... 

Many Viruses Encode Their Own RNA Polymerases RNA-Dependent RNA Polymerases of RNA Viruses Other Types of RNA Synthesis Posttranscriptional Alterations of Transcripts... 

A number of mannose-specific agglutinines (lectins) from Galanthus nivalis, Hippeastrum hybrid, Narcissus pseudonarcissus, Listera ovata, Cymbidium hybrid, Epipactis helleborine, and the N-acetylglucosamine-specific lectin from Urtica dioica have been found to inhibit HIV-1 and HIV-2 infection at similar concentrations as dextran sulfate (IC50 0.2 to 0.6 fig/ml), or even lower (IC50 0.04 to 0.08 pg/ml. Akin to sulfated polysaccharides, the plant lectins also exhibit activity against various enveloped viruses other than HIV, i.e., HSV-1, HSV-2, CMV, RSV, and influenza virus. Plant lectins would primarily interfere with the virus-cell fusion process. Their precise mode of action remains to be resolved. 

Viruses other than HIV may be treated by blocking the action of nucleotide polymerases. Acyclovir (Zovirax, 6.56) and famciclovir (Famvir, 6.57) are used against various herpes viruses (Figure 6.22). Cidofovir (Vistide, 6.58) is active against cytomegaloviral retinitis in patients who are infected with HIV. Ribavirin (Rebetol, 6.59) is approved for use against hepatitis C virus. 

DIP formation in virus stocks can be avoided by infecting insect cells at a low multiplicity of infection (MOI). According to Wickham et al. (1991), a low MOI is used to minimize the probability of a DIP entering in a cell along with an intact helper virion. As a result, some cells receive only intact virus, others only defective virus, or no virus at all. Non-infected cells or cells infected only with defective virus will not produce any more virus, while cells infected with intact virus will produce more intact and infectious viruses than the co-infected cells. Therefore, the DIP fraction will decrease compared with the original inoculum. This causes an increase of virus titer. 

Human diploid cell lines have been utilized classically as in vitro hosts for the propagation of polio, mumps, rubella, cytomegalovirus, varicella-zoster, rabies, hepatitis A, respiratory syncytial virus, parainfluenza and many other viruses. Other uses in the biotechnology industry include large-scale cultivation for the production of various cellular products, such as human interferon beta. 

MCP-l/MCAF 17 Mo, astrocytes, mesotheUal, EC, Os, microglia, airway SMC, F, Ep, K, PBMC, Me, Eo IFN7, IL-1, TNF, IL-6, IE-13, SCF, IE-15, H. pylori, bacteria, respiratory syncytial virus, other viruses Activates Mac, BS and MC Histamine release Favors TH2 polarization... 

Figure 1 Biosynthesis of glycoconjugates in mammalian cells and their cellular interactions with antibodies, toxins, viruses, other cells, and bacteria.

What is the structure of a virus At the center of a virus is its nucleic acid. This is surrounded by a protein coat called a capsid. The combination of the nucleic acid and the capsid is called the nucleocapsid. Many viruses also have a membrane envelope surrounding the nucleocapsid. Some also have protein spikes that help the virus attach to a host cell. Viruses have various shapes. Some are rod shaped, like the tobacco mosaic virus. Others have a hexagonal shape, like the bacteriophage T2 virus. 

Varicella-zoster Virus Other scFv Cell Culture In Vitro [138]... 

Gram-negative bacteria Gram-positive bacteria Mycobacteria Fungi Viruses Other... 

Rhodanine (XXXIV) has been found to inhibit the multiplication of ECHO 12 virus, one of the enteric RNA viruses. Other strains of ECHO and various other RNA and DNA viruses were insensitive. It produced 95 per cent inhibition of virus growth in monkey kidney cells at 17 pg/ml. Cellular RNA synthesis and morphological appearance were unaffected by 150 pg/ml. This work indicated that rhodanine prevented synthesis of the viral protein coat. All the substituted rhodanines examined were inactive or only slightly active and generally more toxic than the unsubstituted compound [177]. 

Viral-Induced Inflammation It is estimated that more than 500 million individuals worldwide are infected with HBV or HCV. Many infections are undetected since the initial signs may be very mild/nonspecific. While patients may spontaneously clear the virus, others develop a chronic infection that may progress to cirrhosis, liver failure, or HCC (Kuehn, 2009). 

Razonable RR (2011) Antiviral drugs for viruses other than human immunodeficiency virus. Mayo Clin Proc 86(10) 1009-1026... 

Many viruses other than picomaviruses also augment lipid synthesis in infected cells. In perhaps the first observation, made as a... 

Lysosomal Effects of Viruses Other than Picornaviruses... 

Many lytic viruses, other than picornaviruses, markedly inhibit host cell protein synthesis during the course of the infectious cycle. None have been investigated to the same extent as poliovirus with respect to the mechanism of this function. However, there are a few preliminary studies which might be interpreted as indications of similar effects on initiation factor activity. 

It is well known that synthetic or natural dsRNAs can serve as potent inhibitors of protein synthesis in various in vitro translation systems derived from mammalian cells (Ehrenfeld and Hunt, 1971 Kaempfer and Kaufman, 1973). A variety of other viral dsRNAs inhibit cell-free protein synthesis. The presence of dsRNA has also been detected by crosslinking experiments in HeLa cells infected with en-cephalomyocarditis virus or the t G114(I) mutant of VSV (Nilsen et al., 1981). Reovirus mRNA and polyadenylated vaccinia RNA transcribed in vitro have both been shown to contain dsRNAs which inhibited protein synthesis in cell-free systems (Baglioni et al., 1978 McDowell et al., 1972). Studies such as these with viruses other than rhabdoviruses are discussed in other chapters of this volume. The question that must be kept in mind is whether the in vitro inhibition of translation initiation by VSV dsRNA or any other viral dsRNA truly represents the sequence of events that takes place in the virus-infected cell. 

The main variation of EM that has been reported is cryo-electron microscopy (GEM). Of the reports on the use of GEM during this review period the most-studied structure is the ribosome (from various organisms) and its associated machinery. There have also been a number of studies on various viruses. Other studies that have been reported include ribonucleoproteins, the RNA guide surveillance complex from E.coli, a p53 tetramer bound to a DNA-encoding transcription factor response element, human RXR/VDR nuclear receptor in complex with its DR3 target DNA, a complex (UPF-EJG) from eukaryotic nonsense-mediated mRNA decay,and of a DNA origami structure. ... 

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