| bacteriophage |
A
virus that specifically infects bacteria. |
| capsid |
The protein covering of
a virus’s nucleic acid core. Capsids exhibit symmetry due to the regular arrangement
of subunits called capsomers. See icosahedron. |
| capsomer |
A
subunit of the virus capsid shaped as a triangle or disc. |
| cytopathic effects |
The degenerative
changes in cells associated with virus infection. Examples: the formation of multinucleate
giant cells (Negri bodies), the prominent cytoplasmic inclusions of nerve cells infected
by rabies virus. |
| endocytosis |
The
process whereby solid and liquid materials are taken into the cell through membrane
invagination and engulfment into a vesicle. |
| enveloped virus |
A virus whose
nucleocapsid is enclosed by a membrane derived in part from the host cell. It usually
contains exposed glycoprotein spikes specific for the virus. |
| icosahedron |
A
regular geometric figure having 20 surfaces that meet to form 12 corners. Some virions
have capsids that resemble icosahedral crystals. |
| in vitro |
Literally means
"in glass," signifying a process or reaction occurring in an artificial
environment, as in a test tube or culture medium |
| latent |
The
state of being inactive. Example: a latent virus or latent infection. |
| lyses |
The physical rupture or
deterioration of a cell. |
| obligate
parasite |
Without
alternative; restricted to a particular characteristic. Example: An obligate parasite
survives and grows only in a host. |
| plaques |
In virus propagation
methods, the clear zone of lysed cells in tissue culture or chick embryo membrane that
corresponds to the area containing viruses. In dental application, the filamentous mass of
microbes that adheres tenaciously to the tooth and predisposes to caries, calculus, or
inflammation |
| prophage |
A
lysogenized bacteriophage; a phage that is latently incorporated into the host chromosome
instead of undergoing viral replication and lysis. |
| temperate phage |
A bacteriophage that
enters into a less virulent state by becoming incorporated into the host genome as a
prophage instead of in the vegetative or lytic form that eventually destroys the cell. |
| transformation |
In
microbial genetics, the transfer of genetic material contained in "naked" DNA
fragments from a donor cell to a competent recipient cell. |
| virion |
An elementary virus
particle in its complete morphological and thus infectious form. A virion consists of the
nucleic acid core surrounded by a capsid, which can be enclosed in an envelope. |
