ET-Ch13 - VIRUSES - General Principles; Focus on Bacterial...

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Unformatted text preview: VIRUSES - General Principles; Focus on Bacterial Yll‘USES * l\l011-lix--*ingr obligate intracellular paraaites * OR the Simplest livingT things; there are (dependa upon 3.50111” definition of “‘life") Viruses ' The}? WAYS contain nucleic acid (DNA or RNA) and a protein coat (the “c-apaicl”)i and SCImsIETle-[ES hare an envelope made of lipidai carhohyflrateat and proteina (basic-all}? ainlilar in atructure to an enhanced plaanla membrane“ but with a DIFFERENT FUNCTION! ') ' 1i-‘iiruaea are Yer}? apecific regarding the typea of cella they can infect; the}? generally infect certain typea of cells in a particular apeciea. Thia ia their H(ZI}ST RANGE * Yiruaea can he aeen by electron 111icroacop}=' ONLY and range from 20 to L000 nl\-I in length. 4.- Eacleriophage T4 fifixEEfi nm 1' Adennvirus Bfinm Emma 1|:.a"iru5 9513 nm J. ‘ Bacteriophage M32 25 nm lil'hu'antl}-'dxa Fla-d Bland Cell nn'l 1D.DDG nm Puliavirus - 33 nm Tuba.ch M053 {2 Virus ESDHED Hm % Vaccinia Uirua 3901100 mm L. r:r::_.'.r' 3'1'1-:'_'_'II'..‘.-::-:‘|~'_'JDIZ'J nm Viral Structure A VIRION ia a mature infective particle cciiaiatiiig cf nucleic acid and prcteiri ccat {and eiii-‘elcpe depending upcii the species) Viruaea can have many ai‘raiigeiueiita cf nucleic acids as: their gehciuea They; may hill-'6- either RNA cr DNA {heifer hcth'L and the nucleic acid may he Single cr drmhle- stranded. and linear cr circular The prcteiii ccat ia referred tc aa the {APSE}. WlllC-ll cchaiata cf subunits called capaciuerea. If the virus: haa ah filli-Tfiltflpfli Spikes; are usually preaeiit {_carhcli}-'d1‘ate-lip1d cciuplexea urhcae fuiicticii we will diacuaa later '} General Morphology HELIC VIRUSES {oilpfloluorofl are: Elflflflfl‘lblfld 111 a 116111.331 configurutlou} usually rosomblo long rods... and thou" Eflpfildfi aro- hollow og-Flmdom Surrouudulg the. nucleic acid. POLYHEDRAL 1.1111363 31‘6 1115111y-3idoul; ufluzflll}? tho C—Ellfifild 13 an iooflahodron {2(2) trmngulm‘ ffluos'}. EN\-EL-{.}PE.D i—Tlrusos 1113}? ha hollonl or lflfllE-Fllfiill‘fll" and floquu'o tho-11‘ mwolopo by tul£111gpflrt of tho 1113311151 luoulbruno of the host coll as; the}? “bud” from the cell {loin-*6 by oxooytoflm'} If 3 1711113 lacks an envolopo 1t 13 said to be "11:?Iliocl”. Elli-“'Elflpfid viruses; are usually 311111131 171111363 COB-{FLEX 171111363 113% a limolyhodml hood math 3 complex tail attached - ljuutorioplmgou Euro oomplo}; 171111363. 55mm Ca psi-d fiheadj DNA q—Ta i| Fi be: hascplam Taxonomy of 11111868 Bnned en — Type efnneleie neidi ilffi—fl3'fiit‘: Strategy and in erpliele . K711113133 are net runnigiied 11 place 111 the “normal” et.-'e1‘nll elneeifientien nyntem. newer-Ten the}? are generally grenped 1nte frnnilien genern rind npeeien {Exactly how dependn upon who you nnld '} A 1.711111 npeeien in 11 group of Vimnen Sharing the name genetie information and eeelegienl nielie. Viral npeeien are net given bineininl nnnien the}? are given nerinnl nrnnen (like influenza $111131 HIV} that de net lint-e tn be underlined er italicized. Taxonomy Examples * RNA VIRUSES — Spec-1&3. HIV {Human ll‘l‘ll‘l‘lullfltlflfl1.3161113}? 1511113} * Family. Ratrmrlrlclala; (Llama. Lfilltl‘iflfllfl — Spamaa PUllCfi-Tlfllfl * Family. lernavu‘ldaa. Genua Entm‘ms'lridaa — Spec-1&3: REll‘Jlfi-S $11113 * Family. Rhabalm-‘u‘ldaa; (llama: Lyaaavfl‘ua * DNA VIRUSES — Spamaa HEW-7 {Humam papillomavu‘ua) * Family. Papavan-mama; Gamla Pap1llo111mr11lla — Spemaa HS‘x-T {:Hm‘paa almplax mm) * Family. Hm‘paavlridaa. Gamma: Sunplaxvfl‘ua Viral cultures ' Tc gm“? a Yil’llfl in thc lalx ita llaat c-clla nnlat bc— prcacnt. * It ia caaicat to grow lmctcricpllagca; phagca arc inc-11b ate-d an a lawn of bacteria and plaqnca clcx'clcp whcrc the}? arc- nnlltiplying. ' Animal Viruaca 111a}='1*cquirc a lining llcat in crdcr ta gnu-*1. atllcrwiac, c-cll c-ulturca cf llcat cells can bc— 115.4ch Viral replication strategies: “life cycles ' \iimooo do not 1111113 61123-11163 for lie}? 1116t11bolio reactions. (og. protein synthooio 111* energy production). ' Thoroforo. the}? 111mm tflko orer a host oer-1L and 1136 its. oollular 111i1£3-i‘1i1161‘}-’ to produce E'il‘fli 61123-111611 and other oompononto. Viral infootion turno 1-1 cell into a foo-tor}? for producing more Viruses. Focus on Bacteriophages: Viruses that. infect. bacteria [)isem'e1*et;l in 1915 Bacteriophage means “Bacteria-eater” Term is often shortened to “phage” Almost all carry their genomes as douhle-stramled DNA. Almost always hare a ““oomplex‘i morpholo lx-lost wider studied are the Viruses ofEi rob}, including the “T-es'en” phages and phage lambda Bacteriophages: Lyth and L}--'sogenic Cycles LYTIC CYCLE A phaga aauaea the: lyaia and death atw lta hast bactermm aa 1t l‘BpllflEltflfi. T-aven pllagea {TE and T4 a113- a-Tlulely Emilie-ilk use the ljfitlfl cycle In the: LYSOGENIC CYCLE" a pllaga incarparataa its llllC-lfi‘lfl acid 111th tl‘lE— heat cell alu‘mnaamne and ramama dormant for a periml of tune- Phage lambda 1a a popular exampla of this: type. Theaa 31'6- callE-d TElx-[PERATE phagaa Stages in the lytic cycle Attaehinent - Sites on the lmeteriophage tail fibera attaeh to fee-eptor aitea on the haeteriunL Penetration - The tail aheath e-tztrntraeta to force the tail eore tln*ough the cell walL and phage DNA entera the cell (the e—apaid ataya outside! I) Bioajsntheaia - t1*anae-1*i1:}tion._. tranalatioiL and replication of Viral DNA oeenra h—Iatnration - New Phage DNA and eapaida are aaaeinhled into Vii‘iona. Releaae - Phage l}-"SUZ}"1116 (leatroya the cell wall, the eell huratai and the new Yififlllfl are releaaeLL Phi-mm Mum and magma. jammy:- n \ .flfiLE-l-SE'HM-lfllh'fliafid mmnm Mtwmmu Wflwd/ calmly 'I‘r I. Mm‘l'mmmnwnm all! mmmhhd hm urn-he'll. Stages in the lysogenic cycle Attachment: Penetration - aanle aa in lytic cycle Viral DNA reconlhinea with the bacterial c-lnonloaonle to form a PROPHAG l The prophage replic-atea with the bacterial DNA and will continue to do ao until aomething (an adyerae enyironnlent for example) triggera it to exc-iae itaelf; it then c-ontinuea with the atepa of the lytic cycle. Thuai the atepa apec-ific- to the lyaogenic cycle can be viewed aa additional atepa added into the middle of the lytic cycle. INHIth . mmmmmm mm whaamaland mmmmm¢mm "laminar-5pm Imme-nrunun .msymhwadmdumhud Mlmhm mum-m. hemnimiu 1min: Remember, l}--’sogen}' can lead to specialized transduction! ...
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ET-Ch13 - VIRUSES - General Principles; Focus on Bacterial...

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