Dwi SutiningsihDwi SutiningsihFKM UNDIPFKM UNDIP

Topik Bahasan :Topik Bahasan :

Sejarah Penemuan VirusSejarah Penemuan VirusSifat – Sifat VirusSifat – Sifat VirusStruktur dan Fungsi virusStruktur dan Fungsi virusMorfologi virusMorfologi virusReplikasi virusReplikasi virusKlasifikasi virusKlasifikasi virus

D. Iwanowsky (1892) & M. Beyerinck D. Iwanowsky (1892) & M. Beyerinck (1899) menemukan virus, penyakit (1899) menemukan virus, penyakit mozaik daun tembakaumozaik daun tembakau

1898 : PMK, dapat melewati filter 1898 : PMK, dapat melewati filter bakteri. Penyebab cacar air adalah virusbakteri. Penyebab cacar air adalah virus

1900 : virus menyebabkan penyakit 1900 : virus menyebabkan penyakit kuningkuning

1911 : filtrat yg tdk mengandung bakteri 1911 : filtrat yg tdk mengandung bakteri dapat menyebabkan pertumbuhan dapat menyebabkan pertumbuhan malignan pada hewan (KANKER)malignan pada hewan (KANKER)

SEJARAH PENEMUAN

1915 : ditemukan bakteriofaga1915 : ditemukan bakteriofaga1920 : mengisolasi virus dg kultur jaringan1920 : mengisolasi virus dg kultur jaringan1931 : mengisolasi virus dg embrio telur1931 : mengisolasi virus dg embrio telur1935 : WM. Stanley mengkristalkan virus 1935 : WM. Stanley mengkristalkan virus

TMV penyebab penyakit mozaik tembakauTMV penyebab penyakit mozaik tembakau1940 : elektron mikroskop 1940 : elektron mikroskop 1952 : sel Hela (Ca cervic Henrieta Lacks)1952 : sel Hela (Ca cervic Henrieta Lacks)

SEJARAH PENEMUAN

Merupakan partikel yg sangat kecilMerupakan partikel yg sangat kecilDapat melalui filter bakteriDapat melalui filter bakteriBersifat parasit obligatBersifat parasit obligatUntuk melihatnya perlu mikroskop Untuk melihatnya perlu mikroskop

elektronelektronUkurannya lebih kecil daripada Ukurannya lebih kecil daripada

bakteribakteri

SIFAT-SIFAT VIRUS

TMV terdiri dari 1 macam asam TMV terdiri dari 1 macam asam nukleat (RNA) yg diselubungi oleh nukleat (RNA) yg diselubungi oleh selubung protein sbg pelindungnyaselubung protein sbg pelindungnya

Virus yg menyerang hewan terdapat Virus yg menyerang hewan terdapat lipid2 & lipoprotein2, biasanya lipid2 & lipoprotein2, biasanya mengandung DNAmengandung DNA

SUSUNAN KIMIA

STRUKTUR DAN FUNGSI Structure :Structure :

A virus particle, A virus particle, also known as a also known as a virion, is essentially virion, is essentially a nucleic acid (DNA a nucleic acid (DNA or RNA) enclosed in or RNA) enclosed in a protein shell or a protein shell or coat. Viruses are coat. Viruses are extremely small, extremely small, approximately 15 - approximately 15 - 25 nanometers in 25 nanometers in diameterdiameter

Adenovirus - Images courtesy of Linda M. Stannard, University of Cape Town.

Genetic MaterialGenetic Material

Viruses may have Viruses may have double-stranded DNA, double-double-stranded DNA, double-stranded RNA, single-stranded DNA or single-stranded RNA, single-stranded DNA or single-stranded RNAstranded RNA. In different viruses, which of the . In different viruses, which of the four is the "genetic material," depends on the four is the "genetic material," depends on the nature and function of the specific virus. nature and function of the specific virus.

The viral genome can consist of a very small The viral genome can consist of a very small number of genes or up to hundreds of genes number of genes or up to hundreds of genes depending on the type of virus. Note that the depending on the type of virus. Note that the genome is typically organized as a long molecule genome is typically organized as a long molecule that is usually straight or circular. that is usually straight or circular.

Protein CoatProtein Coat

The protein coat that envelopes the The protein coat that envelopes the genetic material is known as a genetic material is known as a capsid.capsid. It can have several shapes: It can have several shapes: polyhedral, rod or "complex."polyhedral, rod or "complex." The The protein subunits of the capsid are protein subunits of the capsid are called called capsomerescapsomeres. .

Papillomavirus - polyhedral capsid

Tobacco Mosaic virus - rod-shaped capsid

T4 Bacteriophage - complex capsid

In addition to the protein coat, some In addition to the protein coat, some viruses have specialized structures. viruses have specialized structures. For example, the For example, the flu virus has a flu virus has a membrane-like envelope around its membrane-like envelope around its capsidcapsid. The envelope has both host . The envelope has both host cell and viral components and assists cell and viral components and assists the virus in infecting its hostthe virus in infecting its host

Influenza virus

Capsid additions are also found in Capsid additions are also found in bacteriophages. For example, . For example, bacteriophages can have a protein bacteriophages can have a protein "tail" attached to the capsid that is "tail" attached to the capsid that is used to infect the host bacteria. used to infect the host bacteria.

Bacteriophage

kapsomerkapsomer

kapsid (A) kapsomerkapsid (A) kapsomer

nukleokapsidnukleokapsid Kapsomer Kapsomer RNA lin, ds/ssRNA lin, ds/ss

VirusVirus genom genom

DNA lin/sir,ds/ssDNA lin/sir,ds/ss

kapsul (B)kapsul (B)

MORFOLOGI VIRUS

Partikel virus (virion)Partikel virus (virion)

Besarnya : 0,02-0,3 Besarnya : 0,02-0,3 µm (20-300 nm)µm (20-300 nm)Smallpox : 200 nm, Smallpox : 200 nm, Polio : 28 nmPolio : 28 nm

Mengandung DNA atau RNA yang Mengandung DNA atau RNA yang berbentuk untai tunggal atau gandaberbentuk untai tunggal atau ganda

Genom : ds/ss DNA lin/sirGenom : ds/ss DNA lin/sir ds/ss RNA linds/ss RNA lin

Genom virus yg paling besar : 190 kbGenom virus yg paling besar : 190 kb Genom bakteri : 1000-9000, ada Genom bakteri : 1000-9000, ada

yang 590 kb (intraseluler)yang 590 kb (intraseluler)

PARTIKEL VIRUS (VIRION)

Ada virus genomnya tdk terdiri dari 1 Ada virus genomnya tdk terdiri dari 1 molekul, tetapi terdiri dari beberapa molekul, tetapi terdiri dari beberapa segmen, misal Reovirussegmen, misal Reovirus

Tipe virus :Tipe virus : HelicalHelical : TMV ( : TMV (Tobacco Mosaic VirusTobacco Mosaic Virus)) IcosahedronIcosahedron : virus influenza, bakteriofaga T4 : virus influenza, bakteriofaga T4

Beberapa virus mempunyai enzim di Beberapa virus mempunyai enzim di dalam virion, misal retrovirus :RNA-dalam virion, misal retrovirus :RNA-dependentdependent DNA polimerase ( DNA polimerase (reverse reverse transkriptasetranskriptase))

PARTIKEL VIRUS (VIRION)

VIROIDVIROID

Merupakan ss cir RNA molekul Merupakan ss cir RNA molekul kecilkecil

Tidak punya kapsid bentuk Tidak punya kapsid bentuk ekstraselulernya adalah RNAekstraselulernya adalah RNA

Nukleotida : 246-375Nukleotida : 246-375Kebanyakan menimbulkan penyakit Kebanyakan menimbulkan penyakit

pada tanamanpada tanamanTidak punya “protein-encoding” gene Tidak punya “protein-encoding” gene

sangat tergantung sel inang sangat tergantung sel inang

PRIONPRIONBentuk ekstraselulernya adalah Bentuk ekstraselulernya adalah

protein, bersifat infeksiusprotein, bersifat infeksiusMenyebakan penyakit pada hewan, Menyebakan penyakit pada hewan,

termasuk termasuk mad cow diseasemad cow diseaseMenyebabkan penyakit pada Menyebabkan penyakit pada

manusia:manusia:KuruKuruCreutzfeldt-Jakob diseaseCreutzfeldt-Jakob disease

Perbedaan Virus dengan Sel Hidup

Sel Hidup :Sel Hidup :

1.1. Memiliki 2 tipe Memiliki 2 tipe asam nukleat asam nukleat sekaligussekaligus

2.2. Dapat Dapat mereproduksi mereproduksi semua bagian semua bagian selnyaselnya

3.3. Memiliki sistem Memiliki sistem metabolismemetabolisme

Virus :Virus :1.1. Hanya memiliki 1 Hanya memiliki 1

tipe asam nukleattipe asam nukleat2.2. Tidak dapat Tidak dapat

mereproduksi mereproduksi semua bagian semua bagian selnya, hanya selnya, hanya materi genetik & materi genetik & selubung proteinselubung protein

3.3. Tidak memiliki Tidak memiliki sistem sistem metabolismemetabolisme

REPLIKASI VIRUS

A single virus particle (virion) is in and of itself A single virus particle (virion) is in and of itself essentially inert. It lacks needed components that essentially inert. It lacks needed components that cells have to reproduce. Viruses are cells have to reproduce. Viruses are intracellular intracellular obligate parasitesobligate parasites which means that they cannot which means that they cannot reproduce or express their genes without the help of a reproduce or express their genes without the help of a living cell. living cell.

Once a virus has "infected" a cell, it will "marshal" the Once a virus has "infected" a cell, it will "marshal" the cell's ribosomes, enzymes and much of the cellular cell's ribosomes, enzymes and much of the cellular machinery to reproduce. Unlike what we have seen in machinery to reproduce. Unlike what we have seen in mitosis and and meiosis, viral reproduction produces , viral reproduction produces many, many progeny, that when complete, leave the many, many progeny, that when complete, leave the host cell to infect other cells in the organism. host cell to infect other cells in the organism.

REPLICATION VIRUS

1.1. Perlekatan virus pada permukaan sel Perlekatan virus pada permukaan sel inanginang

2.2. PenetrasiPenetrasi3.3. Pelepasan genom dari kapsidPelepasan genom dari kapsid4.4. Sintesa protein virusSintesa protein virus5.5. Sintesa asam nukleatSintesa asam nukleat6.6. Penyusunan virionPenyusunan virion7.7. Pelepasan virus pada inangPelepasan virus pada inang

Proses ReplikasiProses Replikasi

Reseptor virus pada sel inang biasanya Reseptor virus pada sel inang biasanya merupakan glikoprotein dan merupakan glikoprotein dan mempunyai fungsi lainmempunyai fungsi lain

Replikasi genom :Replikasi genom : Pada DNA ds, sirkuler seperti pada Pada DNA ds, sirkuler seperti pada

replikasi DNA bakteri dua arah & dimulai replikasi DNA bakteri dua arah & dimulai dari “origin”dari “origin”

DNA linear “ multi initiation point”DNA linear “ multi initiation point” Untuk ss DNA satu arah, linear, Untuk ss DNA satu arah, linear,

membentuk sirkulermembentuk sirkuler

Bacteriophage binding to the cell wall of a bacterium

The bacteriophage genome replicates The bacteriophage components and enzymes continue to be produced.

The components of the bacteriophage assemble

Bacteriophage enzyme breaks down the bacterial cell wall causing the bacterium to split open.

Bacteriophage injecting its genetic material into the bacterium

KLASIFIKASI VIRUS DNA

FAMILIFAMILI ASAM ASAM NUKLEATNUKLEAT

ENVELOPEENVELOPE

PapoviridaePapoviridae

PapovaviridaPapovaviridaee

AdenoviridaeAdenoviridae

HerpesviridaeHerpesviridae

PoxviridaePoxviridae

HepadnaviridHepadnaviridaeae

ss DNAss DNA

ds cir DNAds cir DNA

ds DNAds DNA

ds DNAds DNA

ds DNAds DNA

ds cir DNAds cir DNA

--

--

--

++

Compl. coatsCompl. coats

Compl. coatsCompl. coats

KLASIFIKASI VIRUS

FAMILIFAMILI ASAM ASAM NUKLEATNUKLEAT

ENVELOPEENVELOPE

PicomaviridaePicomaviridae

CalciviridaeCalciviridae

ReoviridaeReoviridae

TogaviridaeTogaviridae

FlaviviridaeFlaviviridae

ArenaviridaeArenaviridae

CoronaviridaeCoronaviridae

BunyaviridaeBunyaviridae

OrthomyxoviridaeOrthomyxoviridae

ParamyxoviridaeParamyxoviridae

RhabdoviridaeRhabdoviridae

RetroviridaeRetroviridae

ss RNA (+)ss RNA (+)

ss RNAss RNA

ds RNA segmends RNA segmen

ss RNA (+)ss RNA (+)

ss RNAss RNA

ss RNA segss RNA seg

ss RNA diploidss RNA diploid

ss RNA segss RNA seg

ss RNA (-) segss RNA (-) seg

ss RNA (-)ss RNA (-)

ss RNA (-)ss RNA (-)

ss RNA (+)ss RNA (+)

--

--

--

++

++

++

++

++

++

++

++

++

KLASIFIKASI VIRUS RNA

SpecificitySpecificity

Viruses typically can only infect a limited Viruses typically can only infect a limited number of hosts (also known as host number of hosts (also known as host range). The "range). The "lock and keylock and key" mechanism is " mechanism is the most common explanation for this the most common explanation for this range. Certain proteins on the virus range. Certain proteins on the virus particle must fit certain receptor sites on particle must fit certain receptor sites on the particular host's cell surface. the particular host's cell surface.

Plant viruses are similar to animal Plant viruses are similar to animal viruses in most basic characteristics viruses in most basic characteristics but they can also be markedly but they can also be markedly different. different.

Most plant viruses have RNA as the Most plant viruses have RNA as the genetic materialgenetic material

VIRUS TUMBUHAN

Tobacco Mosaic Virus

There are two common mechanisms that plant There are two common mechanisms that plant viruses use to spread:viruses use to spread:

Horizontal TransmissionHorizontal Transmission

The virus is received from an external source. In order to The virus is received from an external source. In order to "invade" the plant, "invade" the plant, the virus must penetrate the plant's the virus must penetrate the plant's outer protective layer known as the epidermisouter protective layer known as the epidermis ( (epi-, -, -dermis).dermis).Plants that have been damaged by the weather, insects, Plants that have been damaged by the weather, insects, etc. are typically more susceptible to the virus. etc. are typically more susceptible to the virus.

Vertical TransmissionVertical Transmission

In vertical transmission, the virus is inherited from a parent. In vertical transmission, the virus is inherited from a parent. This transmission can occur in both asexual and sexual This transmission can occur in both asexual and sexual reproduction. reproduction.

Colds and the chicken pox are two common Colds and the chicken pox are two common ailments that are caused by viruses.ailments that are caused by viruses.

Animal viruses are intracellular obligate parasites Animal viruses are intracellular obligate parasites that reproduce only after invading the host that reproduce only after invading the host animal cell. animal cell.

VIRUS PADA HEWAN

HIV Infecting Human Lymph Tissue

Virus TypesVirus Types

There are several types of animal viruses. They There are several types of animal viruses. They are commonly grouped into families according to are commonly grouped into families according to the type of the type of genetic materialgenetic material present in the virus: present in the virus:

Double-Stranded DNADouble-Stranded DNA

Double-stranded DNA viruses usually have a Double-stranded DNA viruses usually have a polyhedral or complex structurepolyhedral or complex structure. . Examples include: Papilloma (cervical cancer and Examples include: Papilloma (cervical cancer and warts), Herpes (simplex I and II), Epstein-Barr warts), Herpes (simplex I and II), Epstein-Barr virus (mononucleosis) and Variola (smallpox). virus (mononucleosis) and Variola (smallpox).

Cont. Virus TypesCont. Virus Types

Single-Stranded DNASingle-Stranded DNA

Single-stranded DNA viruses usually have a Single-stranded DNA viruses usually have a polyhedral polyhedral structurestructure and depend on adenoviruses for parts of their and depend on adenoviruses for parts of their growth. growth.

Double-Stranded RNADouble-Stranded RNA

Double-stranded RNA viruses usually have a Double-stranded RNA viruses usually have a polyhedral polyhedral structurestructure with the diarrhea viruses being a common with the diarrhea viruses being a common example. example.

Single-Stranded RNASingle-Stranded RNA

Single-stranded RNA viruses are usually of two subtypes: Single-stranded RNA viruses are usually of two subtypes: those that can serve as mRNA and those that serve as a those that can serve as mRNA and those that serve as a template for mRNA. Examples include: the Rhinovirus template for mRNA. Examples include: the Rhinovirus (common cold), AIDS, Rabies and the Influenza viruses. (common cold), AIDS, Rabies and the Influenza viruses.

Dwi S

Maret 2008