Virus Infections Reguller Asaad 010

7/21/2019 Virus Infections Reguller Asaad 010

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The objectives are that students should beable to know and understand

1. The nature, structure and classification

of viruses. 2. The differences of replication cycle of

viruses between DNA and RNA.

3. The ability of viruses to cause disease and effect viruses on host.



PROPERTIES OF VIRUSES

1. Virus structure consist of Nucleic acid ,

capso!er " capsid and envelope

2. #eno!e can be either DNA or RNA3. Viruses do not have riboso!e

$. Viruses do not replicate by binary fission

%. Viruses ran&e fro! 1' n! to 3(( n! in dia!eter.



). *bli&ate intracellular or&anis!s

+. ensitive to interferon

'. No sensitivity to antibiotics

-. an not &row on artificial !edia.



* The arenavirus family (an RNA virus family) appears to package ribosomes 'accidentally'. The packaged ribosomes appear to play no role in viral protein synthesis.

Differentiation between Bacteria, Mycoplasma, Rickettsia,

Chlamydia and Viruses

Their growthon artificial

edia

!ivision b"binar" fission

#hether the"have both !$%

and R$%

#hetherthe" haveribosoes

Theirsensitivit" toantibiotics

&acteria ' ' ' ' '

("co)lasa ' ' ' ' '

Rickettsia * ' ' ' '

+hla"dia * ' ' ' '

Viruses * * * * *

!$% or R$%



ST%&I,IT- OF VIRUSES

* Stable when added (g+l./ (gSO0/$a.SO0

- Stable is important for preparing

vaccine.

PH 5.00 -9,00

- When exposed to ultra violet lamp

loss



“ CHEMISTRY PROPERTIES OF VIRUSES”

!estro"ed on 12o*32o+/with in 4256

+an be ke)t in *72o+ for several onths

and in *872

o

+ for "ears in $itrogen tank6

To kee) in *8725+ ust be i9ed with

dieth"l sulfo9ide :!(SO; 1 < for

aintenance their activit"6



#br 3.

DNA double heli/

Sugar-phosphate

backbone

Nucleotides



!$% double heli9

Three diension



$U+,EI+ %+I! VIRUS Either !$% or R$%

!$% virus is alwa"s in double

stranded/ e9ce)t Par)ovirus insingle stranded6

R$% virus is alwa"s in singlestranded/ e9ce)t Reovirus in doublestranded6



NAKED ICOSAHEDRAL

NAKED HELICAL



FIVE &%SI+ STRU+TUR%, FOR(S OFVIRUS S-((ETR-

1. Na0ed icosahedral sy!!etry, e.&.

poliovirus, adenovirus, hepatitis A virus.2. Na0ed helical sy!!etry, e.&. tobacco

!osaic virus, so far no hu!an viruses with

this structure 0nown.



3. nveloped icosahedral sy!!etry, e.&. herpes

virus, yellow fever virus, rubella virus

$. nveloped helical sy!!etry, e.&. rabies virus,

influena virus, para influena virus, !u!ps

virus, !easles virus

%. o!ple/ sy!!etry e.&. po/virus



Basic lassification of !iruses

Nucleic acid

" RNA or #NA

" single"stranded or double"stranded

" nonsegmented or segmented

" linear or circular

" if genome is single stranded RNA$ canit function as mRNA%

" &hether genome is diploid (it is inretroviruses)

!irion structure

" symmetry (icosahedral$ helical$comple)

" enveloped or not

" number of capsomers



). nvelope A host cell derived !e!brane,

containin& virus specific anti&ens, that4s is

ac5uired durin& virus !aturation.

+. ytopathic effect 67 consist of !orpholo&ic

alteration of host cell, !ay result in cell death.

'. Virion the !ature virus particle, with all of its

structural co!ponents intact.



Factors which affect host range include >

1. 8hether the virus can &et into the host cell.

2. 9f the virus can enter the cell, is the appropiate

cellular !achinary available for the v9rus to

replicate.

3. 9f the virus can replicate, can infectious virus

&et out of the cell and spread the infection



!"#$S #%P&"'()"*+ 1. DNA V9R: R;9AT9*N

2. RNA V9R: R;9AT9*N 2.1. RNA virus do not co! t"#ir RNA

into $NA.

2.2. RNA virus %"ic" co! t"#ir RNA

into $NA.



+( #%P&"'()"*+



+( !"#$S #%P&"'()"*+

e6g6 %deno virus

1. Attach!ent, enetration and uncoatin&

Viral capsid proteins interact with cellsurface receptors and penetration is probably viaendocytosis. Virion are transported to the nucleusand uncoated . DNA enter nucleus, probably

throu&h a nuclear pore.



.6Earl" transcri)tion and earl" translation > Adenovirus uses host cell poly!erase, early

!RNA trascribed and !RNA processed by host

cell. The DNA replicate by a strand displace!ent!echanis!.

46 ,ate transcri)tion and late translation >

;ate !RNA code predo!inantly forstructural proteins.



06 %ssebl" > occurs in the nucleus DNA

enters the particles after i!!ature capsidare for!ed.The capsid undergo amaturation process, after which the celllyse and the virion lea0 out.

16 &udding? release6 Virions !ay bereleased due to cell lysis. <uddin& virusesdo not necessarily 0ill the cell, so!e !ay

be able to set up persistence.



1&. RNA virus do not co! t"#ir RNA into $NA.

N##d 'n RNA(d##nd#nt RNA(o)!*#r's# tor#)ic't# t"#ir RNA.

No vir') rot#in c'n +# *'d# unti) vir') *(RNA'v'i)'+)#.



1.1. P)us str'nd#d RNA virus#s. The virion R$% is the sae sense as

*R$%@ so ,unction 's *(RNA. This

*R$% can be translated iediatel"

u)on infection of the host cell6

eg6 Picornavirus / )olio virus/ togavirus/flavivirus



1.2. N#-'tiv# str'nd#d RNA virus#s. The virion is negative sense@ as a

co)leentar" to *R$% @ coi#d into t"#co*)#*#nt'r! )us(s#ns# *(RNA. $eeds tocode R$%*de)endent R$%*)ol"erase6

eg6 Orth"9ovirus/ easles virus/

rabies virus/ u)s virus6



1.. $ou+)# str'nd#d RNA virus /dsRNA& The virion R$% is dou+)# str'nd#d @ so

cannot function as *R$% @ needed

RNA( o)!*#r's# @ to ake R$%e6g6 Rotavirus



2&. RNA virus#s %"ic" co! t"#ir RNA into $NA.

Retroviruses @ although )lus*sense/ virionR$% is not release in the c"to)las/ @ so doesnot function as R$%6 Virion RNA s#rv# 's 't#*)'t# ,or R#v#rs# tr'nscrit's# #n0!*#

/RT& @ i**#di't#)! coi#d into $NA6Retroviruses need to code RT enA"e and)ackage it in virion6



T=;y!phocyte

Mu".As''d M'idin

=luco)rotein virus

%ttached to rece)tor +!0B co*rece)tor of sel T



Mu".As''d M'idin

Penetration anduncoating

T*,")hoc"te



Package



HIV Replication 3D Medical Animation.fv



Pathogenesis in the infected )atients involves

1. Trans!ission of the virus and its entry

into the host.

2. Replication of the virus and da!a&e to cell

3. pread of the virus to other cells and or&ans

$. The i!!une response, both as a host defense

and as contributin& cause of certain diseases.

%. ersistent of the virus in so!e instances .



There are four ain effects of virusinfection on the cell>

1. Death

2. >usion of cells to for! !ultinucleated cells.

3. ?ali&nant transfor!ation

$. No apparent !orpholo&ic or function

chan&e



%ntivirus dan Sel "ang terinfeksi



Package



References ;

1. Cohen,J., Powderly,W..,et al, !""#.

$nfect%ous &%seases, ' rd ed%th. (osby.!. )e*%nson, W., and Jawet+, ., !""! (ed%cal

(%crob%ology, a )ange ed%cal book, se*enth ed%th. '. (etseelar, &., and S%pson,&.$..,1/0!.

Pract%cal *%rology, or (ed%cal Students and Pract%s%oners %n 2rop%cal Countr%es, 34ford 5n%*.Press.

#. (%s,C.,&ockrell,.(, et al, !""#.

(ed%cal (%crob%ology, 'rd ed%th.lse*%er (osby.

6. 7%rella, ., 1//8. (%crob%ology and $nfet%ous &%seases,

'rd ed%t%on,W%ll%a 9 W%lk%ns a wa*erly copany. :. $nternet.

Virus Infections Reguller Asaad 010

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