Introduction to Viruses 1

Contagium vivum fluidum

Latin word for poison

Adolf Mayer

Tobacco mosaic disease transferring between plants

Dmitri Ivanovsky

Showed infected sap remained infectious even after filtering through the finest chamberland filters

Martinus Beijerinck

Demonstrated the filterability of the agent; Realized that the disease could be used for serial transmission of disease without loss of potency

Loeffler and Frosh

Identified the first filterable agent from

animals–the virus of FMD (Food & Mouth)

obligatory

Virus is an _ intracellular parasites

living host cell

Virus absolutely require (type of host) to multiply

metabolism

Virus have few or no enzymes of their own for _

DNA, RNA

Virus contains a single type of nucleic acid, either _ or _

protein coat

Virus contains a (type of structural protein) that surrounds the nucleic acid

synthesizing machinery

Virus multiply inside living cells by using the (what machinery) of the cell

nucleic acids

Virus causes the synthesis of specialized structures that can transfer the viral (type of biomacromolecules) to other cells.

Host Range

the spectrum of host cells the virus can infect

plasma membranes

For animal viruses, the receptor sites are on _

Virion

A complete, fully developed viral particle composed of nucleic acid surrounded by a coat

Capsid

The protein coat surrounding the nucleic acid of a virus

capsomere

The capsid is composed of subunits, _, which

can be a single type of viral structure protein or several

types

bacteriophage

In the isolation, cultivation and identification of viruses, _ are the easiest viruses to grow

plaque method

Bacteriophages can be grown either in suspensions of bacteria in liquid media or in bacterial cultures on solid media (what method)

Using living animals, embryonated eggs, cell cultures

Methods involved in growing animal viruses in the laboratory

Embryonated eggs

The use of this method in growing animal viruses in the lab is fairly convenient and inexpensive form of host for many animal viruses

Embryonated eggs

It is used to grow viruses for some vaccines

Cell cultures

Using this method in growing animal viruses is more convenient to work with than whole animals or embryonated eggs

Western blotting

Common example of serological method in viral identifications

Restriction fragment length polymorphism, polymerase chain reaction

Virologists can identify and characterize viruses by using these modern molecular methods: (2)

type of nucleic acid, strategy for replication

In taxonomy of viruses: Classification of viruses is based on (type of what) and (strategy for what)

adenoviridae, papovaviridae

Double-stranded DNA (non-enveloped)

poxviridae, herpesviridae

Double-stranded DNA (enveloped)

parvoviridae

Single-stranded DNA (non-enveloped)

reoviridae

Double-stranded RNA (non-enveloped)

picornaviridae, caliciviridae

Single-stranded RNA, – strand (non-enveloped)

togaviridae, flaviviridae, coronaviridae

Single-stranded RNA, – strand (enveloped)

rhabdoviridae, filoviridae, paraxyoviridae

Single-stranded RNA, – strand (one strand of RNA, enveloped)

orthomyxoviridae, bunyaviridae, arenaviridae

Single-stranded RNA, – strand (multiple strands of RNA, enveloped)

deltaviridae

Single-stranded RNA, – strand (virusoid or satellite RNA)

retroviridae

Single-stranded RNA, produce DNA (enveloped)

hepadnaviridae

Double-stranded DNA, use reverse transcriptase, enveloped