Virus, intact

Keywords. Virus, Viral, Viral structure, Capsid, Dynamic, Capsid mobility, Whole virus, Intact virus, MALDI, Electrospray, Proteins, Inactivation... 

Parasite Viruses. A parasite virus is a virus that attaches to another virus. The host virus moves from computer to computer. When the host virus infects a machine, it infects the machine with the parasite virus instead of itself. In some cases, both viruses become active if they reside in different portions of the OS. Because they do not replicate, parasite viruses have no signature. When an infected computer is scanned by virus-detection software, the host virus is detected and removed, leaving the parasite virus intact and undetectable. 

Fusogenic liposome containing DTA Simple liposome containing DTA UV-inactivated Sendai virus Intact Sendai virus... 

Trauger SA, Junker T, Siuzdak G (2003) Investigating Viral Proteins and Intact Viruses with Mass Spectrometry. 225 257-274... 

The multiple sites that serve as origins for DNA replication in eukaryotes are poorly defined except in a few animal viruses and in yeast. However, it is clear that initiation is regulated both spatially and temporaUy, since clusters of adjacent sites initiate rephcation synchronously. There are suggestions that functional domains of chromatin replicate as intact units, implying that the origins of rephcation are specificaUy located with respect to transcription units. 

Infection with a human immunodeficiency virus (HIV-1 and HIV-2 see Chapter 3) can cause the destruction of the TH cell, which is the eritieal eell of the immune system. This leads to the condition known as acquired immune deficieney syndrome (AIDS). At present, it is still not known why, in some cases, infection with HIV leaves the immune system intact whereas in others it is irreversibly destroyed, giving rise to AIDS. 

Viruses replicate only in living cells so the first viral vaccines were necessarily made in animals smallpox vaccine in the dermis of calves and sheep and rabies vaccines in the spinal cords of rabbits and the brains of mice. Such methods are no longer used in advanced vaccine production and the only intact animal hosts that are used are embryonated hens eggs. Almost all of the vims that is needed for viral vaccine production is obtained from cell cultures infected with vims of the appropriate strain. 

The focus of this chapter is the development of a technique often called wholecell matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) or whole-cell MALDI-TOF MS. Some groups prefer to use terms such as intact or unprocessed rather than whole, but the intended meaning is the same regardless of which word is used. As noted in the first chapter of this book, there are many different methods for the analysis of bacteria. However, for the analysis of intact or unprocessed bacteria, whole-cell MALDI-TOF MS is the most commonly used approach. This method is very rapid. MALDI-TOF MS analysis of whole cells takes only minutes because the samples can be analyzed directly after collection from a bacterial culture suspension. Direct MALDI MS analysis of fungi or viruses is similar in approach1,2 but is not covered in this chapter. MALDI-TOF MS of whole cells was developed with very rapid identification or differentiation of bacteria in mind. The name (whole cell) should not be taken to imply that the cells are literally intact or whole. Rather, it should be taken to mean that the cells that have not been treated or processed in any way specifically for the removal or isolation of any cellular components from any others. In whole-cell analysis the cells have been manipulated only as necessary to... 

In another rather different application, ROA data indicated that the coat protein subunits of intact tobacco rattle virus contain a significant amount of PPII structure, which is possibly associated with sequences previously suggested to be mobile and to be exposed externally in the intact virus particle and which may be associated with its transmission by nematodes (Blanch et al., 2001b). 

Trauger SA, Junker T, Siuzdak G (2003) Investigating Viral Proteins and Intact Viruses with Mass Spectrometry. 225 257-274 Trautwein AX, see Paulsen H (2004) 235 197-219 Trautwein AX, see Winkler H (2004) 235 105-136... 

Borman, A. M., and Kean, K. M. (1997). Intact eukaryotic initiation factor 4G is required for hepatitis A virus internal initiation of translation. Virology 237, 129-136. 

Mass spectrometry requires that the material being studied be converted into a vapor. Great strides have been taken in recent years to address this problem, especially in enticing large, thermally fragile (bio)molecules into the vapor state. Matrix assisted laser ionization-desorption (MALDI) and electrospray ionization (ESI) are two current forefront methods that accomplish this task. Even components of bacteria and intact viruses are being examined with these approaches. John B. Fenn and Koichi Tanaka shared in the award of a Nobel Prize in 2002 for their respective contributions to development of electrospray ionization and soft laser desorption. 

Foot and mouth disease virus (FMDV) VP1 epitope Arabidopsis leaf Serum antibodies reacted strongly with intact FMDV particles. Immunogenic in mice when administered parenterally. Protective against challenge with virulent FVDM. 93... 

Foot and mouth disease virus VP1 epitope Alfalfa leaf Mice developed specific antibody response to synthetic peptide,VP1 epitope, and intact FMDV particle. Immunogenic in mice when administered parenterally or orally. Mice protected against challenge with FMDV vims. 21, 23... 

Rabies virus glycoprotein (G) Tomato leaf and fruit Intact protein forms. 108... 

Some diseases caused by viruses are communicable and easily transferred from an infected individual to anyone in close proximity. Typically, this occurs when the infected individual coughs or sneezes creating an infectious aerosol. These aerosols enter the body of a new host through inhalation and /or contact of the aerosol with the mucous membranes of the eyes, nose, or mouth. In addition, although intact skin is an effective barrier against most pathogens, abrasions, or lacerations circumvents this protective barrier and allows entry of the pathogen into the body. 

The starting material will likely be contaminated by intact, viable hepatitis B viral particles (and perhaps additional viruses, such as HIV). This necessitates introduction of stringent purification procedures to ensure complete removal of any intact viral particles from the product stream. A final product QC test to confirm this entails a 6-month safety test on chimpanzees. 

An alternative approach to the production of subunit vaccines entails their direct chemical synthesis. Peptides identical in sequence to short stretches of pathogen-derived polypeptide antigens can be easily and economically synthesized. The feasibility of this approach was first verified in the 1960s, when a hexapeptide purified from the enzymatic digest of tobacco mosaic virus was found to confer limited immunological protection against subsequent administration of the intact virus. (The hexapeptide hapten was initially coupled to bovine serum albumin, used as a carrier to ensure an immunological response.)... 

It had been known since 1941 that red blood-cells are agglutinated by fluids containing influenza virus. In 1942, G. K. Hirst proved that purified influenza virus is quickly and quantitatively adsorbed on red cells, but that, after the elapse of several hours, the virus particle, apparently intact, has come off the surface of the red cells. After this treatment, cells were unable to be agglutinated by influenza virus or to adsorb virus particles. The problem of the interaction of influenza virus with red cells was attacked in a comprehensive manner by Sir Macfarlane Burnet and his coworkers in Melbourne in the period of... 

M. A. Tito, K. Tars, K. Valegard, J. Hajdu, and C. V. Robinson. Electrospray Time-of-Flight Mass Spectrometry of the Intact MS2 Virus Capsid. J. Am. Chem. Soc., 122(2000) 3550-3551. 

The presence of human papilloma virus (HPV) is associated with female genital tract diseases such as condyloma, Bowenoid papulosis, and cervical, vaginal, and vulvar intraepithelial neoplasia and carcinoma. A general concern is the association of HPV with cervical cancer (Gl). The HPV consists of an icosahedral viral particle (virion) containing 8000 base pairs, a circular, double-stranded piece of DNA surrounded by a protein capsid. Viral replication takes place within the nuclei of infected squamous epithelial cells (H5). Following infection of epithelial cells, the viral DNA penetrates throughout the entire thickness of the epithelium, but intact viruses are found only in the upper layers of tissue. 

There is a conserved part on neuraminidase, and this does not mutate or bind to sialic acid. X-ray crystallography revealed that this conserved part is a cleft with four parts. Drug molecules were designed to fit into this cleft and jam the neuraminidase, so that it is not available to cleave the sialic acid. When the sialic acid remains intact on the hemagglutinin, the virus is unable to attach to new cells and propagate the infection. 

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