virologii k2

8/14/2019 VIROLOGIi K2

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Some viruses are useful

Phage typing of bacteriaSome groups of bacteria,such as some Salmonella species,are classified into strains on the basis of the spectrum ofphages to which they are susceptible. Identification of thephage types of bacterial isolates can provide usefulepidemiological information during outbreaks of disease

caused by these bacteria.

Sources of enzymes.

A number of enzymes used in molecular biology are virusenzymes. Examples include reverse transcriptases from

retroviruses and RNA polymerases from phages.


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Pesticides. Some insect pests are

controlled with Anti-bacterial agents. In the mid-20th century

baculoviruses and myxoma virus has beenused to control rabbits.

Anti-bacterial agents. In the mid-20thcentury phages were used to treat somebacterial infections of humans. Interest

waned with the discovery of antibiotics, buthas been renewed with the emergence of

antibiotic-resistant strains of bacteria.


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Anti-cancer agents.

Genetically modified strains of modified viruses, such as herpes simplex virus

and vaccinia virus, are being investigated for treatment of cancers.These

strains have been modified so that they are able to infect and destroy specifictumour cells, but are unable to infect normal cells.

Gene vectors for protein production.

Viruses such as certain baculoviruses and adenoviruses are used as vectors totake genes into animal cells growing in culture. This technology can be used to

insert into cells genes encoding useful proteins, such as vaccine components,and the cells can then be used for mass production of the proteins.


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Merugikan

Pada tanamanTobacco Mosaic Virus

Potato Mosaic Virus

Hewan

Tetelo pada unggas : Newcastle Diseases VirusCacar pada sapi:Vaccinia virus

Manusia

Influenza : influenza virus

AIDS : Retrovirus

SARS: coronavirus

Flu Burung: Avian virus


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Shingles in an AIDS Patient


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STRUKTUR VIRUS

Struktur partikel Virusbervariasi:ukuran,bentuk dan susunan

kima

Sangat kecil ukuran berkisar 20 400 nm Virion:

Merupakan istilah teknis untuk satu

partikel virus lengkap yang tersusun dariasam nukleat dikelilingi protein


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Virus mempunyai DNA atau RNA di dalam protein

Capsid (Nucleocapsid)


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Structure of Influenza Virus


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Capsid:

Susunan protein yang mengelilingi genom

virus.

Mantel protein yang terdiri dari beberapa

subunit protein(Capsomer)

Pada beberpa virus kapsid ditutupi olehsampul (envelope) yang umumnya terdiri

dari lipid,protein dan karbohidrat Envelop

dapat ditutupi oleh struktur serupa paku(spike) yang merupakan kompleks

karbohidrat dan protein


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Morfologi Capsid:

Helical: protein mirip-pita membentuk spiral disekeliling asam

nukleat. Dapat kaku atau fleksibel. Tobacco mosaic virus

Ebola virus

Polyhedral: banyak sisi. Bentuk umum adalah icosahedron,dengan 20 muka segitiga dan 12 sudut

Poliovirus

Herpesvirus

Complex viruses: bentuk tidak teratur (umum)

Bacteriophages mempunyai serabut, lembaran, dan plat yang terikatcapsid

Poxviruses mempunyai beberapa selubung membungkus asam nukleat.


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Morphology of Herpesviruses

A. Schematic Representation B. Electron micrograph

B

Source: Virology 3rd edition, 1996


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Virus Bersampul

Berbentuk bulatJika virus heliks dan polihedral ditutupi

envelope, maka disebut virus heliks bersampul

(enveloped helical virus) atau virus polihedral

bersampul (enveloped polyhedral virus).

Contoh :

virus influenza (heliks bersampul),

virus herpes simpleks (polihedral bersampul


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Protein virus

Proteins that are components of virions areknown as structural proteins. They have to carry

out a wide range of functions, including

protection of the virus genome

attachment of the virion to a host cell (for

many viruses)

fusion of the virion envelope to a cell

membrane (for enveloped viruses).


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Virus proteins may have additional roles, some of

which may be carried out by structural proteins,

and some by non-structural proteins (proteinssynthesized by the virus in an infected cell but

they are not virion components). These additional

roles include

enzymes, e.g. protease, reverse transcriptase

transcription factors

primers for nucleic acid replication

interference with the immune response of thehost.


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Envelope virus

Envelope virus hewan biasanya muncul dari nukleusatau membran plasma inang, beruplipid dan

karbohidrat

Sedangkan envelope (protein) dikode oleh gen virus

dan keluar ke permukaan envelope sebagai spikesatau peplomers.

Spike dibutuhkan virus untukmenempel pada sel

inang

dapat untuk identifikasi


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Beberapa spike mempunyai:

Enzim neuroamidase

membantu virus dalam penetrasi ke dalam lap

epitelmukosa salurn pernapasan sel inang

Hemagglutinin

membalut/mengikat virion pada membran sel darahmerah dan menyebabkan hemaglutinasi

Glycoprotein

protein yang mempunyai karbohidrat


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Spike berperan pada proses pelekatanvirus pada sel inang.

Virus dengan kapsid yang tidak tertutup

oleh envelop disebut virus telanjang


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Material genetik :

The virion contains the genome of thevirus. Where as the genomes of cells are

composed of double stranded ,there are

four possibilities for a virus

double-stranded DNA (ds DNA)

single-stranded DNA (ss DNA)

double-stranded RNA (ds DNA)single-stranded RNA. (ss RNA)


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Tipe materi genetik virus:Materi genetik dapat untai tunggal atau ganda:

DNA untai tunggal (ssDNA):

Parvoviruses DNA untai ganda (dsDNA):

Herpesviruses Adenoviruses Poxviruses

Hepadnaviruses* (Partially double stranded) RNA untai tunggal (ssRNA): dapat plus (+) atau

minus (-) sense: Picornaviruses (+) Retroviruses (+)

Rhabdoviruses (-) RNA untai ganda (dsRNA):

Reoviruses


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Viruses

Cells

Hepatitis B virus 3.2

Approximate

genome size

(kbp DNA)

Phage 48.5

Mimivirus 1200

Mycoplasma genitalium 5800

Escherichia coli 4700

3200000Human

Genome sizes of some DNA viruses and cells.


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ss, circular

ds, linear

ss, linear

ds, circular

ss, circular

ds, linear

ss, linear

Examples

Parvoviruses

Poxviruses

Phage X174

Baculoviruses

Tobacco mosaic virus

Reoviruses

Hepatitis delta virus

DNA

genomes

RNA genomes

Linear and circular viral genomes.

ss: single-strandedds: double-stranded


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