Vi Sinh-ly Thuyet

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VI SINH VT(TOM TT CHUYN VI SINH VT DANH CHO CHNG TRNH CHUYN.) CHNG I: VI SINH VT CHA C CU TO T BO. CHNG II: HNH THI, CU TRC V HOT NG SNG CA SINH VT NHN S CHNG III: VI SINH VT C NHN NGUYN THY - VI KHUN LAM. CHNG IV: VI SINH VT C NHN CHUN. CHNG V: DINH DNG V PHT TRIN CA VI SINH VT CHNG I: ***&&&**** VI SINH VT CHA C CU TO T BO.

I/ T kha: VSV: i tng ch nhn thy di knh hin vi, gm nhiu nhm nh VK c (Archaea), VK, VR, VNS, mt s to v nm hin vi. VSV c: nhm c th n bo, v ngun gc chng loi pht sinh thuc v c th nhn s (prokaryote), nhng khc bit vi VK. C th v bo: nhng VSV khng c nhn, khng c trao i cht ring, khng c dinh dng c lp, cu to ch gm 2 phn t ch yu l v protein v vt cht di truyn l acid nuclic (ADN hoc ARN), c th v bo gm nhiu nhm: VR, thc khun th (Bacteriophage). C th nhn s (prokaryote): c th sng n bo cha c mng nhn, gm 2 nhnh ln: Archaea, Bacteria. C th nhn chun (Eukaryote): c th m TB c nhn in hnh, c mng nhn v thng c cc c quan khc na. Ton b c th nhn chun ( n bo, a bo: t phn ha v phn ha cao) lp thnh siu gii nhn chun. Trao i cht : ton b phn ng sinh ha trong TB. Tit trng ( v trng, sterile): khng c bt k loi c th no. Bacteriophage ( thc khun th): mt loi VR nhim trong cc TBnhn s ( thng hiu VR ca VK). Prophage (phage n): phn vt cht DT ca phage gia nhp vi NST ca VK, cng c nhn ln khi VK nhn ln (cn gi phage n ha). Lysogen cell (TB sinh tan): mt VK cha prophage. Acid nuclic mch m: l mt mch ADN hoc ARN i m (theo nguyn tc b sung) vi ARNm ca VR.

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Acid nuclic mch dng: mt mch ADN hoc ARN cng trt t nh ARNm caVR.

Prion: mt dng khng bnh thng ca protein TB bnh thng tm thy no ngvt c v. VR hc, prion l mt tc nhn truyn bnh m dng ngoi TB ca n khng cha acid nucleic. VD prion gy bnh b in. Retrovirut: mt loi VR m h gen ARN ca n c ADN trung gian l mt b phn trong chu trnh nhn ln ca chng. Virion: t hp ht VR, acid nucleic c bao bc bi protein v i khi c t hp cht khc na, (thng c hiu nh VR ngoi bo). VR gy c (virulent virut): VR lm tan hay tiu dit TB ch khi nhim vo chng. Protein chng VR: protein c sinh ra do p li interferon c tc dng c ch s nhn ln ca VR. Capsid: v protein ca VR bao quanh acid nucleic. Capsomere: n v hnh thi protein ca capsid. Interferon: mt loi protein chng VR c sinh ra trong TB (thng thy TB ng vt) p li s nhim VR. Viroid: on acid nucleic trn (ADN hoc ARN ) mt mch truyn bnh, ln u tin c tm thy Hoa K, thng c coi l VR tiu gim. Oncogene: mt gen l tc nhn su xa hnh thnh khi u. II/ c im chung ca VR: C dng cha c cu to TB. Ht sc nh b, chui qua c mng lc VK. K sinh bt buc bn trong cc TB vt ch. Mi VR ch k sinh mt TB vt ch nht nh. C th nhn ln trong TB vt ch hnh thnh VR mi. Khi sinh si ny n chng s dng b my DT v hot ng tng hp protein, acid nucleic ca vt ch. C cu to n gin, ch c v capsid v li acid nucleic. ngoi TB vt ch thng dng tim sinh. Khng mn cm vi thuc khng sinh. III/ Hnh thi, kch thc v cu to ca VR: 1/ Kch thc: Quan st bng mt thng Vng quan st knh HV QH 1A 1cm0

1nm

Vng quan st knh hin vi in t 10nm 100nm 1m 10m E. coli 18nm

100m

1mm

Nguyn t 2R= 10cm Nm men

Rui gim 300-400nm 10-20nm VR vim VR ln

Trng iu

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A

ty xm

( HIV) X khun (1 m x 200m)

22nm protein ca 1 loi nhuyn th D B 150nm VK mycoplasua C

-

VR gia TB sng nh nht v phn t hp cht ha hc ln nht: Hp cht ha hc < VR < TB. 2/Hnh dng: cc loi vt ch khc nhau th c hnh dng kch thc khc nhau: Hnh cu: VR cm, quai b. C kch thc trung bnh:100 - 150nm. Hnh que: m thuc l, m khoai ty. Di 250nm, rng: 15nm. Dng nng nc: VR k sinh TB VK. B ngang:10 - 90nm, di 100- 300nm. Khi : gm VR nhiu cnh, VR u ma. KT: 30 - 350 nm. 3/ Cu to ca VR: Siu gii virut tuy phc tp v a dng, nhng c th xp vo 3 nhm cu to sau: a/ Xon tr: Xon tr trn: khng c mng bc bn ngoi v capsid. Xon tr c mng bc: c thm mng bc bn ngoi v capsid. b/ Hnh khi Icosaedre: (Hnh khi c thit lp bi cc tam gic u, c 3 trc i xng v vy chng c i xng khi cu). Gm Icosaedre trn v Icosaedre c v bc. c/ Dng phi hp: (Dng nng nc) c trng cho cc th thc khun u c i xng Icosaedre nhng ch c 2 trc i xng v ui c i xng xon. Gm 2 phn chnh: Bn ngoi l v capsid: bn cht l protein. Capsid c cu to t cc n v hnh thi l capsome. n v hnh thi c th l mt chui polipeptid to thnh nh thuc l, hoc c th c to thnh t cc n phn protin ng nht, m mi n phn c cu to t nhiu chui polipeptid. Capsid cu to t nhiu n v hnh thi ng nht thng c cu to i xng. Capsid c 2 kiu i xng: i xng xon tr, v i xng khi. Cc cu trc i xng khi c lp nn bng cc hnh tam gic u, gi l Icosaedre. Cng thc tnh: N = 10(n - 1)2 + 2. Trong : N l tng s n v hnh thi c trong ht VR. N l s capsome b tr trn mt cnh ca tam gic u. Acid nucleic: ch c mt trong 2 loi hoc ADN hoc ARN. + Cc loi genom ca VR: Cc dng virt Genom trong VR Vi rt ADN ADNss, ADNds Vi rt ARN ARNss, ARNds ARNss (Retrovirut), ADNds (Hepadnavirut) Vi rt ADN ARN Ch : ss: mch n, ds: mch kp.

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+ Cc loi acid nucleic ca VR: ADN: ADNss: mch thng (Pavovirut): ADNss mch vng (mt s phge): ADNds thng: ( nhiu ng vt) ADNds haiu kn ( Vaccinia) ADNds vng xon n hoc phc: ARN: ARNss thng mch dng (+) (ch yu VR thc vt):(+) ARNss thng m (-) khng gy bnh:(-) ARNds thng: Vi rt c li l ADN Vi rt c li ARN VR gy bnh thy u VR bi lit. VR gy bnh TB ln ngi VR gy bnh long mng l mm. VR gi di. VR gy bnh vim no Nht Bn. VR gy vim gan ch Cum, quai b, si, dch hch V. IV/ Hot ng ca VR: 1/ Hot ng ca VR gy c: a/ VR hp ph trn b mt TB vt ch. S hp ph ca VR ln b mt TB l qu trnh l ho v quyt nh bi s khc nhau v in tch cng nh bi nhng lc khc ca sc ht gia cc phn t ca b mt virut v b mt TB. V kch thc nh, cc ht virut trong dung dch bao quanh TB lun lun trng thi vn ng hn lon Brown v mt phn nhng ht ny tip xc vi b mt TB. S hp ph ch xy ra khi c nhng cht in gii nht nh, chng hn cc ion ++ Ca . C l chng trung ho nhng nh tch anion tha thi ca cc i phn t virut v ca b mt TB. Nhng caton a ho tr nhng nng thp th tng cng hp ph, cn nng cao th c ch hp ph. Cc polianion c ch hp ph virut. Ngi ta cho rng cc nhm amin ca virut hin ng vi cc nhm photpht ca mng TB, tuy nhin cc th th ca TB vn ng vai tr quyt nh ch yu. Cc yu t tc ng ln th th TB s nh hng n mc v tc hp ph: Chng hn hoocmn tuyn gip tng cng hp ph virut bi cc TB, cn hoocmn tuyn cn gip th c ch s hp ph virut. Theo bn cht ho hc ca cc th th m trn nhng virut c nh vo thuc 2 nhm: mucoproteit v lipoproteit. Tnh cm th ca TB i vi virut c quyt nh bi 4 nhn t: + C th th m trn virut c th c nh c. + C trong mng TB v trong t bo cht nhng enzim c kh nng ph v protein v gii phng axit nuclic ca virut. + C mt trong TB nhng enzim vt liu v ngun nng lng m bo s tng hp nhng thnh phn ca virut to thnh cc virion. + Cc mt hp ph nm u ui ca phage. Ngoi nhng nhn t trn n cn ph thuc vo nhit ca mi trng.

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Khi c s tng ng gia th th trn b mt vi khun v mt hp ph u si lng ui c nhm ho hc chc nng ph hp th mt phn ng ho hc xy ra dn ti 2 th th gn cht nhau. Nu dng enzim hay ho cht ph hu cc th th hoc dng cc chng t bin khng c th th th TB vi khun khng b nhim virut na, mi TB bm dnh ti 200 phage tng ng. b/ S thm nhp ca virut vo TB. S thm nhp ca virut vo TB u tin c nghin cu trn m hnh ca cc phage T chn. Sau khi ht phage hp ph ln b mt TB v sau khi tch phn cui ca mu (S tch ra ca cc lng nhung vi m c xc tc bi cht km nm trong thnh TB ca vi khun). Tm a ca mu c c gii phng v lizozim ca n lm tan vng tip cn ca TB. Trong lc ny th canxi c gii phng, ng hn l nhng ion Ca++ c gii phng v lm hot ho enzim adenozintriphotphat c mt trong protein co gin ca o bc xung quanh mu. Ao bc ngoi ny co li, y trc ca mu vo t bo cht lm rch mng t bo cht. ADN cha trong u ca phage cng vi mt s t poliamin v protein theo ng mng ca mu tim vo trong t bo cht ca TB vi khun. Theo D.M. Goldfarb (1961), qu trnh thm nhp ca phage vo TB vi khun sau khi hp ph c th chia ra nhng giai on sau: + Tan thnh TB vt ch. + Dn truyn xung ng lm tng sinh thm thu ca mng TB. + Lm thng mng TB. + Phn gii phage thnh protein v axit nuclic. + S xm nhp mm nhim trng ca phage vo trong vi khun. + Phn ng phc hi tnh thm thu lm cho vi khun khng i vi tc ng tiu tan sau ny. Nh vy, trong qu trnh thm nhp ca virut th v protein ngoi TB vt ch. Cho n nay mt vn cha r, theo nhng con ng no axit nuclic ca virut c vn chuyn i, ti sao n khng b tc dng bi nuclaza ca TB m ti sao ni khu tr cui cng ca n, hoc ni cch khc l im xut pht ca n ni bt u nhng qu trnh tng hp cm ng bi virut, li khc nhng virut khc nhau. V im ny c th a ra gi thuyt sau: C l h thng nhng ng dn ni bo l nhng con ng m theo axit nuclic vn c vn chuyn n ni nh trc; chc chnh chng cch bit n v khng gian khi nhng nuclaza ca TB. Kh nng vn chuyn theo c ch ny gin tip c nhn thy t nhng th nghim a ADN ng dng vo TB, ch my pht sau n lt vo trong nhn TB. Cn i vi nhng virut i theo con ng thc bo th c s ci b v protein ca virut. S ph hu v protein din ra trong cc khng bo to nn bi mng TB, sau ny cc khng bo bin i v cc nucleocapxit c mt trong TBC, sau trong TBC "enzim ci o" c to nn, n ci v protein v gii phng ADN ca virut. c/ Tng hp cc thnh phn ca VR. Trc khi tng hp cc thnh phn ca virut c mt thi k chun b, trong thi k ny n thc hin s n p b my di truyn ca TB v tng hp cc enzim c hiu ca virut. Thi k ny ko di mt cch khc nhau cc virut khc nhau v tu thuc vo nhng c im thng tin di truyn c trong axit nucleic ca virut.

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Vn l nhng vt k sinh ni bo tuyt i cc virut tn dng mt cch ti a cc ngun d tr ca TB tng hp nn nhng thnh phn ca mnh, chng hn cc axit amin v nucleotit m t to nn protein v cc axit nuclic ca virut, nhng d tr nng lng di h thng ATP v cc h thng lm hi sinh ATP, cc h thng riboxom m tng hp cc protein v mt phn h thng thc hin s tng hp axit nuclic. trong TB vt ch axit nuclic ca virut cn c TB nhn dng nh kho nhn ng cha kho, s d nh vy l do khi vo trong TB axit nucleic ca virut c bin i cht t khng nh hng n m thng tin TD nh mtil ho hoc glyczil ho cc vng pyrimizin hay purin, lm cho TB nhn bit, lin c x l hoc lm tan nh nuclaza. Sau khi nhn ng nhau ri th axi