Department of Pharmacy Noakhali Science & Technology University

1. Pharmaceutical Microbiology>virus
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Virus
Viruses are non-cellular organisms, which made up of genetic material and
protein that can invade living cells. These microorganisms belong to the
family of validate and Genus of virus. They are considered both a living and
non-living things.
CHARATERISTIS OF VIRUS
 They are enclosed in a protective envelope.
 They have spikes, which helps them to attach to the host cell.
 They are non-cellular.
 They do not respire, do not metabolize and do not grow but they do reproduce.
 They contain a protein coat called the capsid.
 They have a nucleic acid core containing DNA or RNA.
 Ribosomes and enzymes are absent, which are needed for metabolism.
 They are considered both as living and nonliving things, as viruses are inactive when they are
present outside of host cells and are active in side of host cells. As
they make use of raw materials and enzymes of the host cell to
reproduce and causes several infections.
MORPHOLOGY OF VIRUS
Viruses are no cellular, meaning they are biological entities
that do not have a cellular structure. They therefore lack most of the
components of cells, such as organelles, ribosomes, and the plasma
membrane. A virion consists of a nucleic acid core, an outer protein
coating or capsid, and sometimes an outer envelope made of
protein and phospholipid membranes derived from the host cell. Viruses may also contain
additional proteins, such as enzymes, within the capsid or attached to the viral genome.
Viruses come in many shapes and sizes, but these features are consistent for each viral
family. As we have seen, all virions have a nucleic acid genome covered by a protective capsid.
The proteins of the capsid are encoded in the viral genome, and are called capsomeres. Some viral
capsids are simple helices or polyhedral “spheres,” whereas others are quite complex in structure.
COMPOSITON OF VIRUS
A virus is made up of a core of genetic material, either DNA or RNA, surrounded by a protective
coat called a capsid which is made up of protein. A virus is made up of a core of genetic
material, either DNA or RNA, surrounded by a protective coat called a capsid which is made up
of protein.

2. Pharmaceutical Microbiology>virus
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A virus is made up of a core of genetic material, either DNA or RNA, surrounded by a
protective coat called a capsid which is made up of protein. A virus is made up of a core of
genetic material, either DNA or RNA, surrounded by a protective coat called a capsid which is
made up of protein.
TYPES OF VIRUS
Classification of virus on the basis of nucleic acid
1. DNA virus: viral genome is DNA
i) Double stranded DNA virus: eg. Adenovirus, Herpesvirus
ii) Single stranded DNA virus: eg. Parvovirus, φ174 virus
2. RNA virus: genome is RNA
i) Double stranded RNA virus: eg. Reo virus
ii) Single stranded RNA virus: these are further classified into two groups
Positive sense RNA (+RNA): Polio virus, Hepatitis A
Negative sense RNA (-RNA): Rabies virus, Influenza virus
Classification of virus on the basis of structure
1. Cubical virus: they are also known as icosahedral symmetry virus
Eg. Reo virus, Picorna virus
2. Spiral virus: they are also known as helical symmetry virus
Eg. Paramyxovirus, orthomyxovirus
3. Radial symmetry virus: eg.Bacteriophage
4. Complex virus: eg. Pox virus
CULTIVATION OF VIRUS
 One major unique characteristics of viruses is that they can’t multiply outside a living host.
 Because they contain no metabolic enzymes and also they are unable to use environmental
nutrients.
 Therefore, they must have nutrients and enzymes provided by living cells- plants, animals,
human hosts or bacterial cells.
Viruses that use bacterial cells as a host are more easily grown on bacterial cultures.

3. Pharmaceutical Microbiology>virus
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Cultivation in chick embryos:
 Viruses can be cultivated in embryonated eggs.
 A hole is drilled in the shell of the embryonated egg and
a viral suspension is injected in any membrane of the
egg, which is most appropriate for its growth.
 Viral growth is indicated by the death of the embryo, by
embryo cell damage or the formation of lesions on the
egg membranes.
This technique is now used for the production of certain vaccines
]
Cultivation in cell culture:
 Embryonated eggs have been virtually replaced for
experimental purposes with viruses by mammalian,
avian and other vertebrate cells grown in culture.
 Cell culture requires care and skill to exclude microbial
contamination.
 In cell cultures viruses can be grown in primary or
continuous cell lines.
 Cultures made directly from live tissues are primary
cell cultures.
Subcultures from the primary culture are called diploid cell cultures