Characteristics of Viruses and Related Diseases

MASA syndrome, is a rare X-linked recessive neurological disorder. It is caused by mutations in the L1CAM gene.

This is the major structural protein and covers the RNA genome. It protects the genome from nucleases and holds it in a conformation that allows transcription.

Herpes virus are much larger than DNA viruses having a genome size of 100 to 200 kilobases. These are often co-carcinogens. They have a hit and run mechanism of oncogenesis.

During this stage the cellular proteolytic enzymes digest the capsid away from the nucleic acid. This always occurs in the cytoplasm of the host cell. The period of the replication cycle between the end of the uncoating stage and maturation of new viral particles is termed the eclipse. Thus, during the eclipse stage no complete viral particles can be viewed within the cell.

The morphology of a virus is determined by the arrangement of the protomeres. When protomeres aggregate into units of five or six (capsomeres) and then condense to form a geometric figure having 20 equal triangular faces and 12 apices, the virus is said to have icosahedral (cubic) morphology. When protomeres aggregate to form a capped tube, they are said to have helical morphology. Any other arrangement of the protomeres results in a complex morphology.

 LMP-2A is a transmembrane protein that acts to block tyrosine kinase signaling. It inhibits activation of the viral lytic cycle.

Prions are infectious agents composed solely of glycoprotein. They are products of a human gene which accumulate in tissue as amyloid.

Viroids are infectious agents composed solely of circular single-stranded RNA which folds over on itself to form some double stranded regions. These are catalytic RNAs (ribozymes).

These virus are pathogens for both humans and animals. They are pleiomorphic, coated, single positive strand RNA viruses. In the electron microscope, they have a doughnut shape.

Vpr is a Human immunodeficieny viral gene and protein product. Vpr stands for Viral Protein R. It plays an important role in regulating nuclear import of the HIV-1 pre-integration complex and is required for virus replication in non-dividing cells such as macrophages.

Reactivation of the persistent HSV infection is probably due to suppression of the skin immune system.

Pericarditis is an inflammation of the pericardium, which is the fibrous sac surrounding the heart. A characteristic chest pain is often present. This is not associtaed with mumps.

Bacteriophage T12 is a bacteriophage that infects the bacterial species Streptococcus pyogenes and converts a harmless strain of bacteria into a virulent strain. It carries the speA gene which codes for erythrogenic toxin A. speA is also known as streptococcal pyrogenic exotoxin A, scarlet fever toxin A, or even scarlatinal toxin.

NSP1, the product of rotavirus gene 5, is a non-structural RNA-binding protein that contains a cysteine-rich region and is a component of early replication intermediates.

LMP1 is the best-documented oncoprotein of the Epstein–Barr virus (EBV), latent gene products.

Rous sarcoma virus is a retrovirus and is the first oncovirus to have been described. It causes sarcoma in chickens.

This is a rare, progressive, fatal, demyelinating disease of the CNS that kills oligodendrocytes. It results in memory loss, loss of co-ordination, mentation problems, vision problems, etc. The disease is caused by certain members of the polyomavirus family, usually JC virus.

There are at least 93 serotypes in the world, though 23 prevalent serotypes that cause disease in different parts of the world, but no switching of the bacterium between serotypes. Infections with these organisms are common and often infect those with antibody or innate or combined deficiencies.

M13 is a filamentous bacteriophage composed of circular single-stranded DNA (ssDNA) which is 6407 nucleotides long encapsulated in approximately 2700 copies of the major coat protein P8 and capped with 5 copies of two different minor coat proteins (P9, P6, P3) on the ends.

Spuma viruses are exogenous viruses that have specific morphology with prominent surface spikes. The virions contain significant amounts of double-stranded full-length DNA.

EBV is the herpes virus that is most strongly associated with cancer. It infects primarily lymphocytes and epithelial cells. In lymphocytes, the infection is usually non-productive, while virus is shed (productive infection) from infected epithelial cells.

Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome and may have relatively simple or elaborate structures. Their genomes may encode as few as four genes and as many as hundreds of genes.

This is a major portal of entry, though not the only one. The chemokine receptors CXCR4 and CCR5 are also major portals of entry and reduce the CD4 positive helper T cell numbers dramatically.

This is contracted by wrestlers. It apparently spreads by direct contact from skin lesions on one wrestler to his / her opponent, and usually appears in the head and neck region (which are frequent sites of contact in wrestling holds).

CMV is an example of a herpes virus. These are all large DNA viruses of which CMV is the largest and is also known as human herpesvirus-5 (HHV-5).