I HC QUC GIA TP. HCM TRNG I HC BCH KHOA
KHOA K THUT THC PHM
BK
TP H CM
TIU LUN MN C CHT HC
C CHT C SNG TRONG NGUYN LIU T NHINSVTH : NGUYN THI THU HNG -
11110198 NGUYN BO TON - 11110220 CBHD : TS. TRN BCH LAM B MN : CNG
NGH THC PHM V UNG
Tp. H Ch Minh, 10 / 2012
Nhm 8
c t ngun gc t nhin
MC LCTrang KHOA K THUT THC
PHM...................................................................................1
Tp. H Ch Minh, 10 /
2012...............................................................................................1
MC
LC.........................................................................................................................1
Trang.................................................................................................................................1
Bng 1.1: Phn loi cc c t da vo thnh phn ha hc v ha
sinh...........................8I c t Cyanogenic Glycosides
...........................................................................................................9
I.1 Tng quan v c t Cyanogenic
glycoside............................9Bng 1.2: Cc c t Cyanogenic
Glycosides trong 1 s loi thc vt............................10
I.2 c t Cyanogenic Glycosides trong khoai
m:...................11 I.2.1 Phn
b.................................................................................11
I.2.2 Cu to phn t
..................................................................11Hnh
1.1: Cu to phn t c t khoai
m.......................................................................11
I.2.3 C ch gy
c.....................................................................11
I.2.4 Triu chng ng
c............................................................12
I.2.5 Liu gy
c.........................................................................13
I.2.6 Bin php phng
trnh.......................................................13Bng
1.3: Hm lng HCN theo thi gian
ngm.............................................................14
II.1 Phn
b..................................................................................14
II.2 Cu to phn
t.....................................................................15
II.3 C ch gy
c.......................................................................16Hnh
1.3: C ch dn truyn xung thn kinh ca
achetylcholin.......................................16 Hnh 1.4: C
ch c ch hot ng dn truyn xung thn kinh ca
solanin.....................17Trang 1
Nhm 8
c t ngun gc t nhin
I.2.4 Triu chng ng
c............................................................17
I.2.5 Liu gy
c.........................................................................18
I.2.6 Bin php phng
trnh.......................................................18III. c
t t nm
.................................................................................................................................19
III.1 Cc cht c thn
kinh:......................................................19
III.1.1 Cc isoxazole: acid ibotenic v dn xut ca n l
muscimol..........................................................................................20
III.1.2
Muscarin:..........................................................................20Hnh
: Nm Psilocybe
coprophila....................................................................................21
III.1.3 c t tc ng n nguyn sinh
cht:...........................22Bng 1.3: LD50 ca cc c t
nm.................................................................................23
Bng 1.4: Thnh phn cc dn xut ca
amanitin............................................................23
III.1.4 c t gy kch thch h tiu
ha:...................................24 III.1.5 c t ging
Disulfiram: .................................................24Hnh
1.5: Hnh dng nm c
Disulfiram........................................................................25
Hnh 1.6: Cu to ho hc ca
coprine.............................................................................26
PHN 2: C T NGUN GC NG
VT.............................................................27
IV.1 Phn
b:................................................................................33Hnh
2.2: Cu to ho hc ca
TTX.................................................................................33
IV.4 C ch gy
c.....................................................................33Hnh
2.3: C ch gy c xa
TTX..................................................................................34
IV.4.1 Triu chng ng
c.........................................................35 IV.4.2
Liu gy c
.....................................................................35
Trang 2
Nhm 8
c t ngun gc t nhin
IV.4.3 Bin php phng
trnh....................................................35V. Bnh
vim no th xp truyn nhim (Transmissible Spongiform
Encephalopathies-TSES) v
Prions.....................................................................................................................................................35
V.1 Cu to ca protein prion
PrPSc.........................................36V.2 C ch gy
c................................................................................................................................37
Hnh 2.4: M hnh heterodimer (Gi thuyt v c ch ly truyn ca
prion)...................38
V.3 M hnh prion
si:.................................................................38Hnh
2.5: M t ca gi thuyt prion
si..........................................................................39
V.4: Chn on v pht hin
bnh.............................................40Vitamin
A........................................................................................................................41
Bng 2.1: Mt s ngun vitamin
A..................................................................................41VI.1
Cu trc ho
hc...........................................................................................................................41
Hnh 2.6: Cu trc ca vitamin
A.....................................................................................41VI.2
Biu hin v Liu
lng................................................................................................................42
Bng 2.2: Liu lng n vo cho php ca vitamin A theo
tui.......................................42 PH
LC........................................................................................................................43
TI LIU THAM
KHO................................................................................................46
Trang 3
Nhm 8
c t ngun gc t nhin
DANH SCH CC HNHTrang KHOA K THUT THC
PHM...................................................................................1
Tp. H Ch Minh, 10 /
2012...............................................................................................1
MC
LC.........................................................................................................................1
Trang.................................................................................................................................1
Bng 1.1: Phn loi cc c t da vo thnh phn ha hc v ha
sinh...........................8 Bng 1.2: Cc c t Cyanogenic
Glycosides trong 1 s loi thc vt............................10 Hnh
1.1: Cu to phn t c t khoai
m.......................................................................11
Bng 1.3: Hm lng HCN theo thi gian
ngm.............................................................14
Hnh 1.3: C ch dn truyn xung thn kinh ca
achetylcholin.......................................16 Hnh 1.4: C
ch c ch hot ng dn truyn xung thn kinh ca
solanin.....................17 Hnh : Nm Psilocybe
coprophila....................................................................................21
Bng 1.3: LD50 ca cc c t
nm.................................................................................23
Bng 1.4: Thnh phn cc dn xut ca
amanitin............................................................23
Hnh 1.5: Hnh dng nm c
Disulfiram........................................................................25
Hnh 1.6: Cu to ho hc ca
coprine.............................................................................26
PHN 2: C T NGUN GC NG
VT.............................................................27
Hnh 2.2: Cu to ho hc ca
TTX.................................................................................33
Hnh 2.3: C ch gy c xa
TTX..................................................................................34
Hnh 2.4: M hnh heterodimer (Gi thuyt v c ch ly truyn ca
prion)...................38 Hnh 2.5: M t ca gi thuyt prion
si..........................................................................39
Vitamin
A........................................................................................................................41
Bng 2.1: Mt s ngun vitamin
A..................................................................................41
Hnh 2.6: Cu trc ca vitamin
A.....................................................................................41
Trang 4
Nhm 8
c t ngun gc t nhin
Bng 2.2: Liu lng n vo cho php ca vitamin A theo
tui.......................................42 PH
LC........................................................................................................................43
TI LIU THAM
KHO................................................................................................46
Trang 5
Nhm 8
c t ngun gc t nhin
DANH SCH CC BNGTrang KHOA K THUT THC
PHM...................................................................................1
Tp. H Ch Minh, 10 /
2012...............................................................................................1
MC
LC.........................................................................................................................1
Trang.................................................................................................................................1
Bng 1.1: Phn loi cc c t da vo thnh phn ha hc v ha
sinh...........................8 Bng 1.2: Cc c t Cyanogenic
Glycosides trong 1 s loi thc vt............................10 Hnh
1.1: Cu to phn t c t khoai
m.......................................................................11
Bng 1.3: Hm lng HCN theo thi gian
ngm.............................................................14
Hnh 1.3: C ch dn truyn xung thn kinh ca
achetylcholin.......................................16 Hnh 1.4: C
ch c ch hot ng dn truyn xung thn kinh ca
solanin.....................17 Hnh : Nm Psilocybe
coprophila....................................................................................21
Bng 1.3: LD50 ca cc c t
nm.................................................................................23
Bng 1.4: Thnh phn cc dn xut ca
amanitin............................................................23
Hnh 1.5: Hnh dng nm c
Disulfiram........................................................................25
Hnh 1.6: Cu to ho hc ca
coprine.............................................................................26
PHN 2: C T NGUN GC NG
VT.............................................................27
Hnh 2.2: Cu to ho hc ca
TTX.................................................................................33
Hnh 2.3: C ch gy c xa
TTX..................................................................................34
Hnh 2.4: M hnh heterodimer (Gi thuyt v c ch ly truyn ca
prion)...................38 Hnh 2.5: M t ca gi thuyt prion
si..........................................................................39
Vitamin
A........................................................................................................................41
Bng 2.1: Mt s ngun vitamin
A..................................................................................41
Hnh 2.6: Cu trc ca vitamin
A.....................................................................................41
Trang 6
Nhm 8
c t ngun gc t nhin
Bng 2.2: Liu lng n vo cho php ca vitamin A theo
tui.......................................42 PH
LC........................................................................................................................43
TI LIU THAM
KHO................................................................................................46
Trang 7
Nhm 8
c t ngun gc t nhin
PHN 1: C T T THC VTNhiu thnh phn trong thc vt c tc dng lm thuc
nhng cng l cht c i vi con ngi cng nh ng vt. y l sn phm ca qu trnh
chuyn ho th cp bn cnh qu trnh chuyn ho chnh ca thc vt nh chuyn ha
sinh tng hp carbohydrate v cht bo. c t thc hin chc nng quan trng
trong thc vt sng, chng hn flavanoids ph hu gc t do, terpenoids c th
thu ht cn trng th phn v mt s alkaloid c th xua ui ng vt n c hoc cc
cuc tn cng ca cn trng. Bng 1.1: Phn loi cc c t da vo thnh phn ha hc
v ha sinh. I 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 III
3.1 3.1.1 3.1.2 3.1.3 GLYCOSIDE Cyanogenic Glycosides II 2.1
ALKALOID Indole lkaloids(Betacarbolines) Glucosinolates(Goitrogenic
2.2 Gly.) Solanin glycosides Saponins Cardiac Glycosides Coumarins
Furocormarins Isoflavones Coumestans Calcinogenic glycosid
Carboxyatractylosides Vicine/Covicine Nitroglycosides 2.3 2.4 2.5
2.6 2.7 and 2.8 2.9 2.10 2.11 2.12 Piperidine Polycyclic Diterpene
Pyridine Pyrrolizidine Quinolizidine Taxine Tropane Indolizidine
Steroids Tryptamine Terpenoids PHENOLIC TOXICAN Cinnamic Acid
Fagopyricin Gossypol Hypericin
(Nitropropanol gly.) PROTEIN AND AMINO IV ACID Cc cht gy d ng c
ch Amylase Enzymes Lipoxidases 4.1 4.2 4.3 4.4
Trang 8
Nhm 8
c t ngun gc t nhin
3.1.4 3.1.5 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.3
Thiaminase Tocopheroloxidase Lectin Abris Concanavalin Ricin
Robin Protein cytoplasmic thc
4.5 4.6 4.7 4.8 V 5.1 5.2 5.3 5.4 5.5 VI 6.1 6.2
Pterocin Resoricinol Urushiol Tannin LIPID Acid bo
Cyclopropenoid fatty acids Erucic acid Fluoroacetate Glycolipid
CHELATING POISONS Nitrate Nitrites
vt 3.4 Polypeptide 3.5 Amino Acid 3.5.1 Non-nutrient 3.5.1.1
Arginine analogs 3.5.1.2 Canavanine I c t Cyanogenic Glycosides
I.1 Tng quan v c t Cyanogenic glycoside Glucoside l hp cht hu c
c cha glucose v phn khng phi glucose thng gy ra ng c, thng c gi l
Aglucan. Tu theo thnh phn ca Aglucan m c tnh c khc nhau. Cyanogenic
Glycosides: l nhng glycoside c aglucan l HCN v cc dn xut Phn loi
cyanogenic glycoside:
Trang 9
Nhm 8
c t ngun gc t nhin
Bng 1.2: Cc c t Cyanogenic Glycosides trong 1 s loi thc vt
Trang 10
Nhm 8
c t ngun gc t nhin
I.2 c t Cyanogenic Glycosides trong khoai m: I.2.1 Phn b Trong
khoai m tn ti 2 dng cyanides chnh l dng glycoside: linamarin,
lotaustraline v dng khng glycoside (l hydrogen cyanide HCN v
cyanohydride t do). Dng non- glycoside chim t 8-12% tng cyanide
trong c khoai m. Hm lng c t cng khc nhau theo tng ging khoai m, loi
khoai m ngt cha hm lng cyanogenic glycoside (di 10mg/kg tht c ti) t
hn so vi loi ng (trn 20mg/kg). Hm lng cyanide c th chim t 6-370
mg/kg tht c ti, tu thuc vo ging, iu kin pht trin (t, m, nhit ), tui
ca cy. c t tp trung nhi phn v (10-20%). I.2.2 Cu to phn t
Hnh 1.1: Cu to phn t c t khoai m I.2.3 C ch gy c Cht gy c trong
khoai m khi vo ng tiu ha s c men tiu ha thy phn thnh Hydrocyanic
acid (HCN) vo mu gy c. Trong c th, HCN do c i tnh c bit s kt hp vi
ion ferric trong cytochrome oxidase, c ch kh nng s dng oxy ca t bo.
Kt qu, nu nut lng nhiu s dn n ng c cyanide in hnh vi bnh cnh lm sng
ngt do thiu oxy t bo. HCN c trng lng phn t thp, km ion ha. Hp thu
vo c th s c chuyn ha qua gan, phn ln HCN tch ng trong hng cu v ch
mt t l nh n no, tim, thi gian bn hy ca HCN khong 1 gi. C ch o thi:
Cyanide khi vo c th s c chuyn thnh dng thiocyanate 1, l hp cht cha
lu hunh gy bu c. Phn ng c xc tc bi enzyme thiosulphate cyanide
sulphur transferase (rhodanase)c trong hu ht cc m ca con ngi. C cht
chnh cho phn ng ny l thiosulphate v 3-mercaptopyruvate ca cystine v
methionine (nhng aminoTrang 11
Nhm 8
c t ngun gc t nhin
acid cha lu hunh). Vitamin B12 dng hydroxycobalamin cng c nh hng
n s chuyn i thnh dng thiocyanate ca cyanide. Hydroxycobalamin gip
tng kh nng bi tit thiocyanate qua nc tiu. Khong 60-100% cyanide vo
c th s c chuyn thnh dng thiocyanate trong 20h v 80% phn ng kh c ca
cyanide thc hin bi enzyme. Khu phn n thp protein c bit l cc amino
acid cha lu hunh s lm gim kh nng kh cyanide v do con ngi d b tn
thng hn.-
Kiu phn ng gii c th nht, phn ng vi cysteine: cht trao i trung
gian beta-cyano-L-alanine to ra gy hi thn kinh(a) HCN+
H 2S+
CONH2 C N+
CH2SHbeta-cyanoalanineC H2 CHNH2 CO2H L-cysteine-
synthase
CHNH2
CH beta-cyanoalanine 2 H 2O hydrolase CHNH2 CO2H
L-asparagine
CO2H beta-cyano-L-alanine
Kiu phn ng gii c th hai, phn ng vi thiosulfate: sn phm to ra gy
bu c(b) HCN+
-2 S2 O 3
rhodanese
-2 SO3 Sulfite
+
- SCN Thiocyanate
Thiosulfate
I.2.4 Triu chng ng c Cp tnh
Triu chng xy ra rt t ngt, ri lon h hp, ngng th v cht sau 1 hoc 2
gi mc nng. Mc nh hn: C cm gic ng, cay v nng rt c hng, thnh thong co
git hoc t cng cc chi. Chy nc bt, si bt mp, nn ma. C cm gic s hi,
chng mt, chong vng, hoa mt, co cng quai hm. Th gp, kh th, nhp th
khng u. ng mch co tht lm cho huyt p tng, tc mu qua tim chm li, v
sau lon nhp tim.
Trang 12
Nhm 8
c t ngun gc t nhin
Nim mc tm, ti xanh, mu mu chocola. Sau l nhng cn co git, khng iu
khin c tiu tin. Cui cng l v m hi, dn ng t, t lit, lit h hp ri ngng
tim v t vong.
Mn tnh: Trng hp n thc phm nhim HCN liu thp, ko di, c th thch ng
v chu ng c, nhng trng thi bnh khc xut hin nh:
Bu c do suy nhc chc nng tuyn gip (hyperthroidism) c lin quan n s
c ch gip trng ca sn phm trao i cht ca HCN l thiocyanate. C th t lit
thn kinh lu di c lin quan n cht trao i trung gian cyanoalanine.
I.2.5 Liu gy c Theo ti liu ca Humphreys (1988) th liu gy ng c ti
thiu ca HCN t do trn ng vt l 2 2,3 mg/kg th trng.
Nu gc CN nm trong cu trc glucoside th cha sc gy ng c. Khi
glucoside trong thc n i vo c th, gii phng nhanh HCN v c th hp thu
nhanh th c th gy c, nu gii phng HCN chm, hp thu chm th liu ny cng
cha gy triu chng ng c.
Trong thc tin, khi ng vt n thc n nhiu v hp thu nhanh th mt lng
HCN l 4 mg/kg th trng c th gy t vong. Nu tnh trn nguyn liu lm thc n
th mc ng c 20 mg HCN /100 g thc n l rt nguy him cho ng vt.
Liu gy ng c trn loi ng vt khc nhau cng khc nhau: - Trn cu 2 2,5
mg / kg th trng. -Trn ngi liu 1,4 mg / kg th trng, hoc 30 -35 mg
HCN/ 1 ngi
ln l xut hin triu chng ng c c th gy cht. Liu LD50 cho dng HCN t
do i vi ngi ln l 50-60 mg, dng lin kt cha xc nh r rng. I.2.6 Bin
php phng trnh Lin kt gia glucose v aglucan s c enzyme linamarase
trong h tiu ho ca ngi thu phn thnh HCN. Khi dng HCN n d ho tan
trong nc v im si 25oC nn c th loi b d dng bng cch ngm trong nc. Nu
khoai m t c tc dng ln c t trong n nh glycoside linamarin, v n c kh
nng khng vi nhit ng thi enzyme phn hu n li b bt hot nhit 75oC. Do
trong nhiu quy trnh,Trang 13
Nhm 8
c t ngun gc t nhin
ngi ta da vo enzyme thu phn gim hm lng glycoside. i vi loi khoai
m ngt, do t c hn do c th n ti hay un nh m khng gy hi. Ngc li i vi
khoai m ng th phi tri qua qu trnh: lt v, mi xt, ln men, kh nc, phi,
sy hay nu. Tuy nhin v ng khng phi du hiu lun lun ng cho s hin din
ca cyanide. Mt qu trnh loi c t hiu qu chnh l ln men, gip gii phng
enzyme linamarase trong cu trc c, sau enzyme ny s thu phn linamarin
thnh glycoside v hydrogen cyanide. HCN ho tan vo nc v d dng bc hi
nhit 28oC. Phi kh l 1 giai on kh c tuy nhin hiu qu khng cao.
Cyanide s khng chuyn thnh dng t do ng thi enzyme s b ph hu trong
sut qu trnh. Phi kh ch lm gim 60-70% tng cyanide trong 2 thng u bo
qun. Do trong c khoai m kh vn cn hm lng cyanide cao (30-100mg/kg).
Nu cng khng phi l bin php tt nht cho qu trnh kh c v ch c 1 phn
linamarin c trch ly vo nc nu, v ch 1 phn c gii phng thnh dng t do.
Kh nng loi c bng phng php nu cn ph thuc vo iu kin nu nguyn liu chng
hn nu khoai m nhit nc 27oC v nhit 100oC sau 30 pht cho thy hm lng
cyanide cn li trong phng php u tin l 8% trong khi phng php 2 l 30%
Bng 1.3: Hm lng HCN theo thi gian ngm Soaking period (days)
Remaining (percentage) 0 1 2 3 4 5 100.0 55.0 42.3 19.0 10.9 2.7
HCN
II Cht c Solanin Glycoside trong khoai ty II.1 Phn b Khi c khoai
ty tip xc vi nh sng sut thi gian thu hoch, s lm cho v khoai ty b
chuyn mu xanh, iu ny gii thch l do qu trnh tng hp chlorophyll
ng
Trang 14
Nhm 8
c t ngun gc t nhin
thi n cng to ra v ng, chnh l thnh phn glycoalkaloids, tuy nhin
vic hnh thnh 2 hp cht ny l 2 qu trnh c lp. Glycoalkaloids tp trung
nhiu cc v tr m qu trnh chuyn ha din ra mnh chng hn; hoa, l non,
chi, v, v cc khu vc gn vi mt c khoai ty. C cn non cha
glycoalkaloids rt cao. Glycoalkaloids trong c khoai ty chim khong
210mg/100g (c ti) (Rastovski et al, 1981). Nng cao nht
glycoalkaloids c tm thy trong phn v ngoi v phn st v ngoi ca c khoai
ty. Nu lt b v th c th loi b khong 60% glycoside alkaloid. Khoai ty
cha hm lng glycoalkaloid ln hn 1mg/100g c xem nh l khng an ton vi
ngi. II.2 Cu to phn t Trong khoai ty, thnh phn glycoside alkaloid
ch yu l anpha-chaconine:anphasolanine vi t l 26:74 v 40:60. Loi ng
ch yu trong -solanine l galactose, trong khi -chaconine l glucose.
Glycoalkaloide gip cy chng li s tn cng ca cn trng, ci lnh v vi sinh
vt
R=
Hnh 1.2: Cu to ho hc ca c t solanin
Trang 15
Nhm 8
c t ngun gc t nhin
II.3 C ch gy c
Hnh 1.3: C ch dn truyn xung thn kinh ca achetylcholin Hot ng n
gin nht ca h thn kinh bt k mt loi vt no cng ph thuc vo s truyn tn
hiu in gi l cc xung thn kinh n hay i ra khi nhng b phn khc nhau ca
c th. S truyn tn hiu ny c lin quan n tng t bo mang thng tin - l cc
nron v cc cu trc nh b l cc synap, chng cho php cc xung thn kinh c
truyn t nron ny sang nron khc. Bt k cung phn x thn kinh no d n gin
hay phc tp cng u c cu to t mt s nron ni vi nhau qua cc synap. Cc v
tr tn cng axon ca mt nron tip xc vi cc nron khc v vi cc t bo c c gi
l cc synap. Cu trc ca mt synap c minh ho hnh 10.1. Hu ht cc synap
ch cho xung ng i mt chiu, l nh cc cht trung gian ho hc cn thit cho
s dn truyn. Cht trung gian c cha trong cc ti hay cc bng nh tn cng
mng trc ca mt dy thn kinh, khi mt xung thn kinh n , mt vi ti ho nhp
vi mng trc synap v gii phng cht vo mt khe nh gi l khe synap. Khi c
gii phng ra khi mng trc synap, n khuch tn nhanh qua khe synap v kt
hp vi c quan th cm mng ca nron th hai cn gi l mng sau synap. Kt qu
lm thay i tnh thm ca mng, lm ion Na+ i vo sau synap, gy kh cc mng
nron v lm xut hin in th sau synap. in th ny nh hn v ko di hn so vi
xung thn kinh. in th sau synap khng tun theo quy lut tt c hay khng
c g, m cng ln nh ca n ph thuc vo s lng cht ho hc trung gian c gii
phng. Nng acetylcholin tc dng ln mng sau synap khng duy tr mc cao c
lu bi v kheTrang 16
Nhm 8
c t ngun gc t nhin
synap cha nhng enzym cholinesterase rt mnh, chng nhanh chng phn
hu acetylcholin, gip cho in th ngh (hay cn gi l in th tnh) mng sau
synap c hi phc v dn sch synap, do xung ng tip theo mi c truyn qua.
Acetylcholin dng khng hot ng t khe synap nhanh chng quay tr li tn
cng trc synap, n s hot ng tr li v c ti s dng. S lin kt ca
acetylcholin vi mng sau synap lm thay i tnh thm ion ca n mt cch r
rt. Phn t acetylcholin m ra mt loi knh cation hu nh to ra tnh thm
cn bng ca Na+ v K+. dn ca c Na+ v K+ tng trong vng 0,1miligiy, ko
theo mt lng ln Na+ vo trong v mt lng nh K+ ra ngoi. S xm nhp ca Na+
vo trong gy ra s kh cc mng sau synap v sinh ra mt in th hot ng. S
chy vo ca Na+ ln hn rt nhiu so vi s chy ra ca K+, do gradient in th
qua mng l do Na+ sinh ra. Acetylcholinesterase l enzyme thu phn
acetylcholine thnh choline v acetate
Hnh 1.4: C ch c ch hot ng dn truyn xung thn kinh ca solanin
Solanine gy c ch acetylcholinesterase ngn cn vic thu phn
acetylcholine. S tch t acetylcholine trong khe synap dn n vic kch
thch qu mc cc neuron th cm. Khi mt neuron b cht i s lm ph hu n cc
neuron bn cnh, to nn mt hiu ng lan truyn. I.2.4 Triu chng ng c n qu
nhiu khoai ty v xanh s b nhim c solanine vi cc biu hin nh bun nn,
tiu chy, i ma, au bng, ri lon, th ngn, thm ch dn n t vong.
Trang 17
Nhm 8
c t ngun gc t nhin
I.2.5 Liu gy c Mc d khng c quy nh r rng v hm lng glycoalkaloid
trong khoai ty nhng hm lng glycoalkaloids c th chp nhn c trong
khoai ty l khng vt qua 200 mg glycoalkaloid trn kg c ti. LD50 cho
chut l 590 mg/kg (0.68 mmol/kg), cho th 40 mg/kg (0.046 mmol/kg)
I.2.6 Bin php phng trnh Hn ch tip xc vi nh sng Nu tip xc vi nh sng
n s tr nn xanh v c v ng do s hnh thnh glycoalkaloids. n hunh quang
cng l nguyn nhn lm tng glycoalkaloids, nhiu nghin cu ch ra rng nu s
dng nh sng thy ngn s gip gim hm lng glycoalkaloids v ci thin cht
lng sn phm. Nhit tn tr Tn tr nhit thp (0 - 5C) lm tng v ng trong c
khoai ty cng nh hm lng glycoalkaloids so vi nhit cao (trn 20C).
Trong tt c cc trng hp tn tr nhit lnh s gip ko di thi gian bo qun
khoai ty nhng nhit thp (0 5C) v stress l cc yu t tng cng tch ly
glycoalkaloid.-
S tn thng v h hng Bt k s tn thng v h hng no trn c cng s lm tng
tch ly
glycoalkaloids. Bnh hi, cn trng tn cng trn c trong qu trnh sau
thu hoch cng s khi u cho vic tng hp glycoalkaloid.-
Ch bin
Lt v Trong c khoai ty, glycoalkaloids tp trung nhiu 1.5mm t lp v
ngoi vo trong. Nu gt b lp ny s gip loi b 60% - 95% glycoalkaloids.
Cooking Glycoalkaloids tng i n nh v t b tc ng bi nhit si, lm lnh kh
hay s kh nc. Nu nhit trn 170oC, chin b su c hiu qu loi tr c t. Nhng
phng php khc t c hiu qu lm gim nng ca hp cht ny. X l ho cht/vt
l
Trang 18
Nhm 8
c t ngun gc t nhin
Tia Gamma cng c tc dng iu chnh nng glycoalkaloid, c bit l cc c b
h hng. X l ha hc ch yu l c ch s pht trin ca chi tuy nhin n cng gip
lm gim s tch t glycoalkaloid. III. c t t nm Nm l mn n ca nhiu ngi
trn th gii, mt s loi c pht trin thnh cc sn phm thng mivi s lng ng
k. Vn sc khe c th pht sinh cho vic thu hi nm hoang d. Trn ton th
gii c khong 5000 loi nm, trong , hn 100 loi nm c v hn 300 loi nm n
c. c t t nm hin nay c chia lm 4 loi: c t thn kinh: gy ra cc triu
chng thn kinh nh ra m hi nhiu, o gic, trm cm, kch thch, co git v hn
m. c t tc ng n nguyn sinh cht: hy hoi cc t bo v tip theo l cc c
quan b suy yu. Gy kch ng ng tiu ha: bun nn, bng au qun, nn ma, v
tiu chy. Cc loi c t ging Disulfram: nhng cht ny thng khng gy c v
khng c cc triu chng, tuy nhin nu tiu th cn trong vng 72 ting sau
khi n, chng c th gy ra i ma, bun nn, nhc u, bng mt v ri lon tim
mch. III.1 Cc cht c thn kinh: c trng bi nm Amanita muscaria, thuc h
nm tn Amanitaceae. Qu nm c mu rc hay cam, mu sc c th nht dn sau ma,
c ph nhng vy mu trng, ng knh t 10-15 cm, cung v vng mu trng hoc
vng, chn phnh dng c, tht nm khng c mi v c bit. Nm mc n c hay thnh
cm. Loi nm ny trng rt p cn c gi l nm bay, nm v tr, c ni cn gi l nm
rui v dng lm b dit rui. Ngoi ra, c t thn kinh cn c tm thy cc loi
Clitocybe v Inocybe.
Trang 19
Nhm 8
c t ngun gc t nhin
Hnh : cu trc ca cc cht hot ng A. muscaria. III.1.1 Cc isoxazole:
acid ibotenic v dn xut ca n l muscimol. Acid ibotenic l mt acid
amin c tc dng kch thch, n m phng hot ng ca cc cht dn truyn xung thn
kinh ca t bo thn kinh trong h thn kinh trung ng, gy mt mi v sau gic
ng l chng au na u, v chng au u ny c th ko di trong vi tun. Khi nm
kh, acid ibotenic chuyn thnh muscimol vi tim nng gy c cao hn. Cc
triu chng thn kinh sn xut t A. muscaria c th rt khc nhau nhng ni
chung bt u xy ra t 30 n 90 pht sau khi tiu ha. Sau khi tiu th khong
15 mg muscimol mt trng thi tng t nh nhim c cn xut hin: nhm ln, bn
chn, ri lon th gic, co tht c, v c th m sng km theo. Bnh nhn thng i
vo gic ng su sau giai on kch thch, v h t nh hoc qun hon ton sau khi
thc dy. III.1.2 Muscarin: Mt hp cht c hot tnh sinh hc quan trng khc
c sinh ra trong A. muscaria l muscarin. Dn xut furan ny chu trch
nhim chnh cho c tnh dit cn trng ca A. muscarin. Muscarin l cht ph
giao cm c nghin cu v gy ra hot ha su rng trn h thng thn kinh ph
giao cm ngoi vi. Muscarin khng nh hng ln h thn kinh trung ng v n
khng qua c hng ro mu no, do c s phn cc cao ca nguyn t Nit tch in
dng. Cc triu chng xut hin trong khong 30 pht sau khi tiu ha. Cc
triu chng gm tng tit nc bt, chy nc mt v m hi, tip theo l nn ma v
tiu chy. T vong khng ph bin do bnh nhn thng p ng atropine sulfate,
l mt cht i khng vi cc th th muscarin. Do ng c muscarin sau khi n A.
muscaria l tng i him, ngi ta cho rng mc muscarin trong nm thp so vi
cc hp cht thn kinh khc.Trang 20
Nhm 8
c t ngun gc t nhin
Psilocybin v psilocin: cc hp cht chnh trong nm ma thut.
Hnh : Nm Psilocybe coprophila C hai gy hiu ng o gic: thay i thc
ti, o gic, cm gic hng phn Chng l cc dn xut hydroxytryptamine lin
quan n serotonin. Psilocin l mt tryptamine v mt alkaloid, vi cc tn
ha hc khc l 4-HO-DMT, Tryptamine, 4-hydroxy-N,Ndimethyl. Ngi ta cho
rng sau khi ung, psilocybin d dng chuyn i thnh psilocin. Liu lng
hot ng ca psilocin l 2-20 mg trong thi gian t 4-7 gi. Liu hiu qu ca
psilocybin l 4-8 mg (khong 2g nm kh). o gic c th gim bng
chlorpromazine, v co git gim bng diazepam.
LD50 ca psilocybin: 285mg/kg ( chut,) 280mg/kg (chut cng,)
12,5mg/kg ( th,)Trang 21
Nhm 8
c t ngun gc t nhin
III.1.3 c t tc ng n nguyn sinh cht: Amatoxin:
Mc tiu ca cht c ny l c ch RNA polymerase II, enzyme tng hp mRNA
cc t bo, can thip vo qu trnh phin m RNA kt qu l mt ci cht n chm.
Nhng nh hng ca -amanitin rt n tng , bao gm phn r cc nucleoli, dn n
ngn vic hnh thnh tng hp nn ribosome l ni tng hp nn protein. Hot ng
trao i cht m ph thuc vo tng hp protein vi tc cao nh cc t bo lt h
tiu ha, t bo gan, v cc tiu qun phc tp cn tm ca thn b nh hng nng n.
Kt qu l gan b ph hy vi mc nghim trng tng t vi b bc x ion liu cao.
amanitin cng hy hoi cc tiu qun ca thn, lm gim hiu qu lc cht c khng
in phn ca thn t mu. Liu gy t vong ngi trng thnh l 5-10 mg. Ng c
amatoxin: Giai on 1: giai on lag trong khong thi gian 10-12 gi,
trong khi c t c hp th qua h tiu ha v bt u tn cng gan v thn. Giai on
2: giai on tiu ha, khi bt u c cc triu chng: au bng d di, bun nn, nn
ma, m sng, o gic, mt nc h ng huyt. Giai on 3: suy yu ng tiu ha. Cc
du hiu mt sau 3-4 ngy, ngi bnh b vng da, ri lon thn, vim gan, to
gan, xut huyt gan. Giai on 4: suy gan v thn, ngng tim dn n t vong
trong vng 6-8 ngy.
Trang 22
Nhm 8
c t ngun gc t nhin
Bng 1.3: LD50 ca cc c t nm Tn -amanitin -amanitin -amanitin
-amanitin Amanin Amaninamid Amanullin Amanullinayre Proamanullin
LD50 0,3-0,6 0,5 0,2-0,5 0,3-0,6 0,5 0,5 >20 >20 >20
Cha tr: khng c bin php gii c khi ng c amatoxin. Bin php duy nht
l ngay lp tc x rut, lc mu, nu tht bi c th tin hnh ghp gan. a
thiotic acid trong glucose vo trong tnh mch c ngh s dng. iu tr theo
phng php ca bc s Bastien vi cc thuc: vitamin C, nifuroxazide v
dihydrostreptomycin, cht in gii, v penicillin. Silibinin, mt cht c
tm thy trong cy k sa, c cho l mt cht tim nng cho vic gii c
amatoxin, tuy vy vn cn c nhng nghin cu thm. Bng 1.4: Thnh phn cc dn
xut ca amanitin Tn -amanitin -amanitin -amanitin -amanitin
Amanullin Amaninamid Amanin Amanullinayre Proamanullin R OH OH H H
H OH OH H H1
R2 OH OH OH OH H OH OH H H
R3 NH2 OH NH2 OH NH2 NH2 OH H NH2
R4 OH OH OH OH OH H H OH OH
R5 OH OH OH OH OH OH OH OH H
Trang 23
Nhm 8
c t ngun gc t nhin
III.1.4 c t gy kch thch h tiu ha: Mt lot cc cht c khng xc nh c
kt hp vi nm hoang thng c b ngoi ging cc loi nm n c, bao gm
Jack-O-Lantern (Omphalotus illudens) gn ging vi Chanterelle
(Cantharellus cibarius) v Green-spored Lepiota (Chlorophyllum
molybdites) gn tng t nh nm Parasol (Macrolepiota procera). Vic nut
phi l nguyn nhn gy suy tiu ha nh bun nn, nn, tiu chy, au bng chut
rt sau khong 30 n 90 pht khi n.Triu chng thng r rng ln mt cch t
nhin trong 3-4 gi, v hon thnh phc hi ch mt mt ngy hoc lu hn. Trng
hp t vong rt him xy ra, thng do s suy kit ca bnh nhn (qu nh hay ln
tui). iu tr: bao gm ra d dy, gim st tnh trng mt nc, gim huyt p, hoc
suy gim chc nng thn. III.1.5 c t ging Disulfiram: c bit ca cc c t
nm l coprine, mt acid amin c sn xut bi chi nm Coprinus, c bit l C.
atramenarius, cn gi l Alcohol Inky.
Coprinopsis atramentaria
Trang 24
Nhm 8
c t ngun gc t nhin
Coprinopsis variegata Hnh 1.5: Hnh dng nm c Disulfiram Coprine c
chuyn i thnh cyclopropanone hydrat trong c th con ngi. Hp cht ny cn
tr s phn hy ru, c t lin kt vi molypden v ngn chn hot ng
acetaldehyde dehydrogenase. Ng c coprine l ng c acetaldehyde. S suy
gim ca ethanol:-
Bc 1: Alcohol dehydrogenase CH3CH2OH + NAD+ CH3CHO + NADH +
H+
ethanol Acetaldehyde dehydrogenase CH3CHO + NAD+ + H2O
acetaldehyde
acetaldehyde
CH3COOH + NADH + H+ acetic acid
V tng ng vi antabuse (hay disulfiram), cng l mt cht ngn chn qu
trnh oxy ha ca ru trong giai on acealdehyde, i khi n c gi l mt cht
c ging nh disulfiram.
Trang 25
Nhm 8
c t ngun gc t nhin
Hnh 1.6: Cu to ho hc ca coprine Cc triu chng bt u n 1 gi sau khi
ung ru trong vng 4 n 5 ngy sau khi n nm hoc cng vi nm: bng ca c v
mt, v kim loi trong ming, cm gic nga ran cc chi, t tay, nhc u, tnh
mch c p nhanh, ngc au, bun nn, m hi, i ma. Vic phc hi thng xy ra mt
cch t nhin trong vng vi gi.
Trang 26
Nhm 8
c t ngun gc t nhin
PHN 2: C T NGUN GC NG VTI. Tng quan Cc loi c t sinh hc bin to ra
mi nguy him e do sc kho ngi tiu th sn phm bin. nhng c t ny gm c
nhiu loi khc nhau, tt c chng sinh ra t loi to v vi sinh vt bin c
trong t nhin. To l mt xch s ng nht trong chui thc n bin. N b cc loi
ng vt bin (nhuyn th, gip xc v c) n vo tch lu v chuyn ho thnh c t,
cui cng con ngi n nhng ng vt ny ri b ng c. Phn ln cc c t ny c trong
loi nhuyn th, 2 mnh v v mt s loi c. tin cho vic phn tch, kim tra, c
t trong cc loi hi sn, ngi ta chia c t theo 2 ngun, trong mi ngun
ngi ta li chia theo tnh cht gy bnh v cu trc ho hc ca c t: Nhm c t
lin quan n loi nhuyn th:-
Lit c (Paralytic Shellfish poisoning) PSP Hi chng thn kinh
(Neurotoxin Shellfish Poisoning) NSP Tiu chy (Diarrhetic Shellfish
Poisoning) DSP ng tr (Amnesic Shellfish Poisoning) ASP Ciguatera
Fish Poisoning CFP: Tetrodotoxin fugufish poisoning TFP
Gempylotoxin Scombroid "Thy triu " hay s "n hoa" ca to l cch gi ch
hin tng bng n v
Nhm c t c lin quan n c:-
-
II. Hin tng thu triu s lng ca to bin. S "n hoa" ca to c khi lm
nc bin mu , c khi mu xanh, mu xm hoc nh mu cm gon nay,cc nh khoa hc
xc nhn c khong 300 loi vi to bin hnh thnh s n hoa lm thay i mu nc
bin. Trong c khong 1/4 loi (70 - 80 loi) gy hin tng n hoa c kh nng
sn sinh c t ang l mi e da n h ng vt v thc vt t nhin nc, cng nh ngh
nui trng thy sn v sc khe ca con ngi (nguyn nhn do c t to c th c tch
ly
Trang 27
Nhm 8
c t ngun gc t nhin
trong vi loi ng vt thn mm s, c hay c v khng b ph hy trong qu
trnh un nu, khng nh hng n mi v ca thc phm). Qu trnh n hoa ch yu xy
ra vng ven bin, vng nc m. Cc yu t gy nh hng n s gia tng ca thu triu
:
S gia tng nhit b mt bin, gim nng mui, tng lng cht dinh dng trong
mi trng bin, bin lng, nhng t ma sau sut ma h nng nng.
Ngoi ra, thu triu c th ly lan trn din rng bi gi, dng chy, nhng
cn bo hoc tu thuyn. Cc yu t khc, nh s khuch tn mt lng ln bi giu st
t cc sa mc rng ln nh sa mc Sahara, nh bin i kh hu trn qui m ln nh
El Nino cng c th c xem nh l mt trong nhng nguyn nhn gy ra thu triu
. Lin quan n nhiu yu t x hi, t nhin khc nhau: nhng khu vc tp trung
nui c lng v nui tm, lng thc n d tha v cht thi ca tm, c l ngun dinh
dng rt phong ph cho cc loi to c Trn thc t, thu triu l hin tng t
nhin c th xy ra bt cht hoc theo chu k hng nm. Nu trong nc co qua
nhiu Nit thi tao va cac phiu sinh vt se tng nhanh chong v s lng tao
nn mu o hay nu trong nc. C quan bao v mi trng cua My c lng rng khi
nng N0x trong nc t 12% n 44% se tao nn s phu dng cho to. Trong giai
on bo xc, vi to tn ti di dng tim sinh y ct thm lc a. Vo mt thi im
no m con ngi kh on trc, chng sn sinh rt nhanh vi mt dy c (60-70
triu t bo trong 1 lt nc), bin nc bin t mu xanh chuyn sang vng nht,
vng thm ri nh pha mu. Cc loi to v vi khun c cha cc sc t mu khc
nhau, sng tri ni di nhng iu kin mi trng nht nh c th sinh trng thnh
cc qun th to ln vng ven b gy nn s i mu nc S pht trin ca thu triu
chia thnh bn giai on. Giai on u tin l s xut hin ca to trong khu vc.
Tip theo l giai on tng trng dn s bt u nhn ln nhanh chng trong thi
gian vi tun. Khi chng t n s lng ti a th chng bt u giai on ba l n
hoa v theo nhng t gi i vo gn b. Cui cng, qu trnh n hoa chm dt v kt
thc chu k.Trang 28
Nhm 8
c t ngun gc t nhin
Ngi ta chia hin tng n hoa ca to c thnh mt s loi sau: Cc loi khng
cha c t nhng khi n hoa lm thay i mu nc;di nhng
iu kin c bit nh: trong cc vnh kn, to n hoa c th tng n mt rt cao
lm cn kit oxy gy cht ng vt vng ny. Tiu biu trong nhm ny l cc loi:
Gonyaulax polygramma, Noctiluca scintillans (to gip), Trichodesmium
erythraeum (tolam). Cc loi khng c vi ngi nhng li c vi c v cc ng
vtkhng xng sng (c bit trong cc h thng nui thm canh) do ph hy hoc lm
tc cc mang ca chng; bao gm cc loi to khu Chaetoceros convolutus, to
gip Gymnodinium mikimotoi,.... Cc loi sn sinh ra cc c t mnh gy nn
mt lot cc chng bnh v thn kinh v tiu ha. i din ca to Gip, c cc loi
thuc chi Dinophysis,Goniaulax v Prorocentrum c tnh c rt cao. c t ca
nhm ny c phn loi nh sau: - PSP (Paralytic Shellfish Poisoning) do
cc loi to gip: Alexandriumacatenella, A. Catenella, A. Cohorticula,
... sn sinh ra. - DSP (Diarrhetic Shellfish Poisoning) do cc loi to
gip Dinophysisacuta, D. Acuminata, D. Fortii, D. Norvergica, ... sn
sinh ra - ASP (Amnesic Shellfish Poisoning) do cc loi to khu
Pseudonitzschiamultiseries, P. Pseudodelicatissima, P. Australis,
... sn sinh ra. - CFP (Ciguatera Fish Poisoning) do cc loi to gip
ch yu sng y Gambierdiscus toxicus, Ostreopsis spp, Prorocentrum
spp, ... sn sinh ra. - NSP (Neurotoxic Shellfish Poisoning) do cc
loi Gymnodinium breve, Gymnodinium G. Cf.breve (New Zealand), ...
sn sinh ra. - Cc c t to lam do cc loi to lam Anabaena circinalis,
Mycrocystisaeruginosa, Nodularia spumigena, ... sn sinh ra.III.
c t gy tiu chy trong nhuyn th (DSP - Diarrhetic Shellfish
Poisoning)
Trang 29
Nhm 8
c t ngun gc t nhin
Trang 30
Nhm 8
c t ngun gc t nhin
III.1. S phn b
Hnh 2.1: Mt s loi Molluscan Ng c gy lit c thng c lin quan n vic
tiu th loi nhuyn th Molluscan (s, hu, ip, vm) b nhim c. DSP c sn
xut bi loi to Dinophysis v Prococentrum, c t ny bao gm acid okadaic
v cc dn xut ca n. III.2. Cu trc ho hc- C ch gy c: Cu trc phn t ca
acid okadaic l 1 dn xut ca 1 loi acid bo cao phn t ti v tr C38 :
C44H68O13.
Trang 31
Nhm 8
c t ngun gc t nhin
c t DSP l nhng hp cht bn nhit a bo v l polyether, tu thuc vo dn
xut khc nhau m c ch tc ng ca loi c t ny cng khc nhau:
Nhm cht c c tnh axit, bao gm okadaic acid (OA) v cc dn xut ca n
c t tn l dinophysistoxins (DTXs). OA v cc dn xut ca n (DTX1, DTX2 v
DTX3) c tch ly trong cc m m ca nhuyn th. Cc hp cht ny l cht c ch
phosphatase mnh gy vim ng rut v tiu chy ngi. Axit OA gy ra cc cn co
tht ko di ca c trn ng mch ca con ngi. C trn c kch hot bi 1 n v ca
myosin nn ngi ta cho rng OA c tc ng c ch phosphatase ca chui myosin
nh. OA th hin l mt cht c ch mnh ca serine / threonine phosphatases
(PP1 v PP2A), PP2A s c ch mnh hn 200 ln so vi PP1. Protein
Phosphatases (PP) l mt nhm enzym quan trng lin quan cht ch vi nhiu
qu trnh trao i cht trong t bo: Phosphoryl ha v dephosphorylation
trong t bo nhn chun, trao i cht vn chuyn qua mng, v bi tit, co bp,
phn chia t bo. Phosphatases kh nhy cm vi OA, nh PP1 v PP2A. S tiu
chy ngi gy ra bi s phosphoryl qu mc ca cc protein kim sot bi tit
natri t bo ng rut.
OA v DTX1 cng thc y s pht trin ca cc khi u th nghim trn ng vt.
DTX1 ln u tin c pht hin trong Dinophysis fortii ti Nht Bn, DTX2 c
xc nh trong tm, cua, s, hn Ireland.
Nhm bao gm mt hp cht sunfat yessotoxin (YTX), v dn xut ca n l 45
hydroxyyessotoxin (45-OH-YTX). Yessotoxin ln u tin c phn lp t c
quan tiu ha ca s ip (Patinopecten yessoensis) ti Nht Bn. Cc
yessotoxins khng gy tiu chy, nhng yessotoxin tn cng c tim chut sau
khi c tim, trong khi desulfate yessotoxin li gy tn thng gan.
III.3. Triu chng ng c: Sau khi n, trong vng 30 pht n 12 gi, nn
nhn b tiu chy, bun nn, i ma, au bng, bnh phc sau 3 ngy. Trng hp
nng, sau khi n nn nhn thy nga, t mi, cm gic nght th, v c th cht v
lit c h hp trong vng 2-24 gi. Ch s LD-50: 192 g.kg (i.p.)
chut.IV.
c t c nc
Trang 32
Nhm 8
c t ngun gc t nhin
IV.1 Phn b:
Hnh 2.2: Cu to ho hc ca TTX Trn Th gii ngi ta xc nh c c 131 loi
c nc sng trong mi trng nc khu vc nhit i hoc cn nhit i ca Thi Bnh
Dng, i Ty Dng c 55 loi sinh sng bin Nht Bn, 66 loi bin Vit Nam. Ng
c c nc l ng c hay gp v c bit n nhiu nht trong cc lai ng c do c gy
ra t xa n nay. Hin ti, ngi ta bit vi khun thuc h
Vibrionaceae,Pseudomonas, v Photobacterium phosphoreum sn sinh ra
TTX. Khi n to v rong bin c nc tch t cc vi khun ny,v cung cp cho
chng mi trng thch hp pht trin v sn sinh TTX vo trong cc m ca c nc.
C nc s dng cht c ny t v v sn mi. Bnh thng TTX tn ti dng tin c t
tetrodamine khng c, phn b ch yu gan, bung trng v rut, c t tng ln ma
trng. Tht c thng khng c. Khi c b p cht hoc b n th tetrodamine chuyn
ha thnh TTX gy c. Cht c t rut ngm vo tht c hoc khi ch bin khng lai
b ht ph tang gy ng c. TTX l mt cht c thn kinh mnh, l 1 hp cht phi
protein c tn l: Anhydrotetrodotoxin-epitetrotoxin hay acid
tectonic. TTX l tinh th khng mu, khng mi khng v tan tt trong nc v
dung mi hu c, khng tan trong acid. c tnh n nh ,tnh khng nhit cao,
tnh lin kt cao. TTX c gp 10 ln nc rn h mang v hn gp 10.000 ln
cyanua (cng khi lng) IV.4 C ch gy c TTX gy ra tnh trng t lit c, thn
kinh trung ng, t l t vong rt cao
Trang 33
Nhm 8
c t ngun gc t nhin
Hnh 2.3: C ch gy c xa TTX TTX l cht c thn kinh rt c hiu, bao vy
c hiu cng tch in ca cc knh Natri nm trn b mt ca mng t bo thn kinh.
Phn t ny c cha mt nhm Guanidin tch in dng (lm tng tnh n nh cho cc
cation, nn nhm cht c thn kinh ny c tn gi l cht c guanidin), v vng
Pyrimidin vi s tng cng hp nht cc h thng vng (vic thm cc h thng vng
ny, lm cho ton b cha 5 nhm hydroxyl, chc chn h tr cho tnh bn vng ca
phc h lin kt ga TTX vi knh Natri ti phn a nc). S lin kt ca TTX vi
knh Natri rt nhy. TTX c tc dng rt ging tc dng ca hydrat Natri, khi
xm nhp vo ming knh lin lin kt vi nhm peptit glutamat, sau tht cht
vng li khi peptit thay i cu hnh khng gian ca na phn lin kt. Do vy
phc h nhn dng thay i, hn na TTX tn cng vo cc in tch c tc dng m cng
ca knh Na+ (hu qu th hai xy ra trong c th khi dehydrat phc h
nc-Na+). S bm cht ca tetrodotoxin c nc lm bao vy s truyn dn xung
thn kinh ti phc h Na+- knh c gii thch r rng hn bi thi gian chim gi
lu ca TTX so vi hydrat Na+ trong phc h. Hydrat natri c th o ngc lin
kt trong thi gian 1 nano giy, trong khi TTX lin kt vi knh v tn ti
trong thi gian c tnh bng ly tha 10 ca giy l mt khong thi gian v cng
ln. Vi lng ln cc phn t TTX ny khng cho natri c c hi xm nhp vo knh,
s di chuyn natri b bao vy vi hiu lc cao v in th hot ng dc theo mng
thn kinh b dng li. TTX kha ng xung thn kinh dc theo si trc thn kinh
gy t lit h hp lm nn nhn ng c
Trang 34
Nhm 8
c t ngun gc t nhin
t vong. Mt miligram TTX hoc t hn (mt lng nh nh u kim), cng git
cht mt ngi trng thnh. Tm li: C ch gy c thn kinh ca cc c t TTX ca c
nc hoc STX ca nguyn sinh ng vt l cc c t ny bao vy knh Na+ bng cch
bm vo cc peptt ca knh lm thay i s nhn dng phc h nc Na+ t lm ngng s
dn truyn xung thn kinh vi hiu qu rt cao. IV.4.1 Triu chng ng c C th
han tan khng c tnh min dch vi TTX do TTX khng b phn gii bi cc men
tiu ha. Thng sau khi tiu th c t c nc, cc triu chng thng xut hin rt
nhanh t 5 n 20 pht, ph tuc vo liu lng cht c. Thi gian phn hy v bi
tit trong c th rt lu nhng xut hin triu chng ng c sau khi n th rt
ngn 1: T lit nh mi v li, c th c hoc khng c cc triu chng tiu ha (ch
yu l bun nn). Triu chng ny xut hin t 20 pht n ba gi sau khi n c nc
c c 2: T b li, mt v cc vng khc ca c th; lit vn ng sm, ni ngng; cc
phn x bnh thng. 3: Lit mm tan thn, suy h hp (kh th); ni khng thnh
ting v ng t gin c nh; nhng bnh nhn vn cn tnh to 4: Lit h hp nng v
thiu oxy; h huyt p, nhp tim chm v lan nhp tim; c th mt thc, c th
cht trong vng 30 pht. IV.4.2 Liu gy c c tnh ca c nc i vi c th con
ngi: Liu gy cht i vi ngi : 0.5 n 2 mg IV.4.3 Bin php phng trnh Khng
s dng cc sn phm t c nc V. Bnh vim no th xp truyn nhim
(Transmissible Spongiform Encephalopathies-TSES) v Prions Bnh ly
nhim vim no th xp (TSE), cn c gi l bnh prion, l nhng bnh nh hng n
no v h thng thn kinh ca nhiu loi ng vt, bao gm con ngi do s ph hp
DNA.(2)
Trang 35
Nhm 8
c t ngun gc t nhin
Khng ging nh nhng bnh truyn nhim khc c lan truyn bi vi khun,
trong nhng nm 1960, gi thuyt v mt loi protein l tc nhn ca cc bnh
TSE c pht trin gii thch s truyn nhim k l ca cn bnh Scrapie cu v
CreutfeldJacob (CJD) ngi (1). Protein c ny c t tn Prion kt hp 2 m
tit u ca proteinacous (thuc protein) v infectious (truyn nhim) vo
nm 1982 bi Stanley B. Prusiner. Cc protein prion mo m mang bnh ly
truyn gia cc c nhn v l nguyn nhn gy ra s suy gim no. Tt c cc bnh c
bit n gy ra bi prion gi chung l TSE, u khng th cha khi v gy t vong.
Cc bnh c cho l do prion gy ra: con ngi: Bnh Creutzfeldt-Jakob (CJD)
v cc dng khc ca bnh ny Hi chng Gerstmann-Straussler-Scheinker (GSS)
Chng mt ng gia nh gy t vong (FFI) Chng mt ng gy t vong (SFI) Kuru
Hi chng Alpers. ng vt: Bnh Scrapie cu v d Bnh vim no th xp b (BSE)
gia sc Bnh vim no ly nhim chn (TME- Transmissible mink
encephalopathy) Bnh CWD (Chronic wasting disease) hu v la Bnh vim
no th xp mo (FSE- Feline spongiform encephalopathy) Bnh vim no l ng
vt c mng (EUE- Exotic ungulate encephalopathy) Bnh vim no th xp iu.
V.1 Cu to ca protein prion PrPSc Prion di dng scrapie l tc nhn gy
bnh gm nhng protein dng cu trc gp , to nn cu trc cc k n nh c kh nng
khng s bin tnh do ha cht v cc tc nhn vt l, do kh khn trong vic x l
v ngn chn.
Trang 36
Nhm 8
c t ngun gc t nhin
PrPc l loi protein bnh thng trn mng t bo, c 209 acid amin (
ngi), c mt lin kt disulfide, khi lng phn t 35-36 kDa, v ch yu c cu
trc xon alpha, n cng c mt vi cu trc mng lin kt. Protein bnh thng
khng c kh nng trm tch, ngha l khng th phn tch bng k thut ly tm. Chc
nng ca PrPc phc tp vn ang c tm hiu, n lin kt vi ion ng (II) vi i lc
cao. PrPc b ph v d dng bi proteinase K, v cng c th c phng thch bi t
b mt t bo in vitro bi cc enzyme phosphoinositide phospholipase C
(PI-PLC). PrPc cng c cho rng c vai tr quan trng trong vic bm dnh
gia t bo vi t bo, v cc tn hiu ni bo in vivo, v do n c th tham gia
vo vic truyn thng tin gia cc t bo no. ng dng truyn nhim PrPSc vn
cha c bit chnh xc cu trc 3D, nhng ngi ta cho rng n c t l cao cu trc
gp khc lp thay th cho cu trc cun xon , t cho thy thay v d b phn hy
bi cc protease th cc PrPSc khng b tc dng ca enzyme ny v c tnh cht
khng tan. S tp trung ca cu trc bt thng ny hnh thnh nn cc si amyloid
c cu trc cao hn, v tch ly to thnh mng bm. im cui mi si ng vai tr nh
mt khun mu cho php mt phn t protein t do gn vo cho php cc si tip tc
ko di. V.2 C ch gy c Hu ht cc TSE u l t pht v xut hin con vt khng h
c t bin protein prion. S truyn TSE xy ra con vt mang mt alen prion
t bin him, v khi ng vt khe mnh s dng cc m b nhim c t nhng con vt
khc mc bnh. Bnh TSE khng th truyn qua khng kh hay cc tip xc thng
thng khc. Tuy nhin, chng c th truyn qua khi tip xc vi m bnh, th dch
hay cc dng c y t b nhim. Gi thuyt v m hnh hot ng ca prion: Protein
prion c tm thy ngay c ngi v ng vt khe mnh. Prion c mt trong nhng
phn ly nhim, c cu trc khc nhau v khng proteinase, l nhng enzyme
trong c th c th ph v cc protein. Prion gy bnh thoi ha thn kinh bng
cch tp hp cc ngoi bo h thng thn kinh trung ng, t hnh thnh cc mng bm
(amyloid), ph v cu trc ca nhng m bnh thng. S ph v ny c trng bi cc l
m c kt cu xp, kt qu l hnh thnh khng bo trong t bo thn kinh.
Trang 37
Nhm 8
c t ngun gc t nhin
Hnh 2.4: M hnh heterodimer (Gi thuyt v c ch ly truyn ca prion)
Protein dng bnh thng c gi l PrPc , v dng ly nhim c gi l PrPSc, vi c
vit tt ca t cellular hay common, Sc cp n bnh Scrapie cu (cn bnh u
tin c lin quan n prion). Cc dng truyn nhim PrPSc c th xc tc thay i
cu to ca cc protein PrPc thnh cc ng dng truyn nhim, v s truyn nhim
li tip tc cc PrPSc mi. V.3 M hnh prion si: Manfred Eigen cho rng m
hnh Heterodimer i hi PrPSc c hot ng xc tc cc k hiu qu, h s gia tng
tc ca phn ng chuyn i khong 1015. iu ny l khng th pht sinh nu PrPSc
ch tn ti trong cc hnh thc tng hp nh amyloid, l ni s tng tc hot ng
nh mt ro cn n s chuyn i t pht ny. Hn na, d n lc nhng vic truyn nhim
t mt PrPSc vn cha bao gi phn tch ra. Mt m hnh thay th ra i, cho rng
PrPSc ch tn ti dng si v phn cui ca si ni vi mt PrPc v chuyn n thnh
PrPSc. Nh vy sau s lng ca prion s tng tuyn tnh, hnh thnh cc si di
hn. Tuy nhin s tng trng theo cp s nhn c hai PrPSc v cc ht truyn
nhim c quan st thy trong bnh prion. iu ny c th c gii thch bng vic
tnh n s ph v ca cc si. Tc gia tng ny ph thuc
Trang 38
Nhm 8
c t ngun gc t nhin
ln vo nng ca PrPc. Thi k bnh xc nh da vo tc gia tng theo cp s
nhn, v nhng nghin cu bnh prion in vivo chut ph hp vi d on ny
Hnh 2.5: M t ca gi thuyt prion si Tm hiu c ch hot ng nhn rng ca
prion c ngha trong vic pht trin thuc iu tr. Do thi gian bnh ca bnh
prion kh di, nn mt loi thuc hiu qu khng cn loi b ht cc prion m n
gin ch cn lm chm tc tng trng theo cp s nhn ca n. t c iu ny m hnh d
on c cch hiu qu nht l tm loi thuc c th lin kt vi im cui ca si v ngn
chn chng pht trin thm na. V. Biu hin ca bnh S tn thng gy thoi ha m
no do bnh prion gy ra con ngi (CJD, GSS, Kuru) c c trng bi: thay i
to thnh th xp, t bo thn kinh mt i, astrocytosis, v s hnh thnh mng
amyloid. Nhng c im ny tng ng khi xem xt cc bnh prion ng vt. Cc du
hiu lm sng ngi rt khc nhau, nhng thng bao gm cc c im: s thay i cu
nhn cch, c cc vn v tm thn nh trm cm, thiu phi hp, hay dng i khng
vng. bnh nhn cng c th c cc cn rung git c, cm gic khng bnh thng, mt
ng, l ln, hay c cc vn v tr nh.Trang 39
Nhm 8
c t ngun gc t nhin
Trong giai on sau ca bnh, bnh nhn b suy gim tinh thn nng (mt tr
nh), mt kh nng di chuyn v ni chuyn. i vi bnh BSE gia sc, thi gian
lm sng ca bnh ko di ch trong khong vi tun, din ra lin tc v gy t
vong. Bnh ny ln u tin c ghi nhn l Anh (thng 11, 1986), BSE t ti nh
im vo nm 1992 khi 36.680 trng hp c xc nhn. Hu ht cc ca bnh BSE u
xut hin cc ng vt trng thnh c hai gii, thng t nm tui tr ln. V.4: Chn
on v pht hin bnh Thi gian bnh t vi thng n vi thp k, trong thi gian
ny mc d c nhng protein no bnh thng bt u chuyn ha thnh PrPSc nhng vn
khng c triu chng r rng. Hin nay vn cha c phng php no pht hin PrPSc
ng tin cy ngoi tr cch kim tra no b bng nhng phng php bnh l hc thn
kinh, v ha hc m min dch sau khi cht. Tch t bt thng ca cc protein
PrPSc c np gp l mt c tnh ca bnh, nhng mc ca protein ny li thp cc
dch c th nh mu v nc tiu. Do m hin nay cc phng php o lng PrPSc trong
mu vn cha c chp nhn y . Trong nm 2010, mt nhm nghin cu t New York m
t phng php pht hin PrPSc ngay khi chng chim mt phn 100.000 triu
(10-11) trong m no. Phng php ny kt hp s khuch i ca cng ngh mi l
SOFIA (Surround optical fiber immunoassay) v mt s khng th c hiu
chng PrPSc. Sau khi khuch i v c c PrPSc, cc mu c dn nhn bi mt loi
thuc nhum hunh quang bng cch s dng khng th c hiu, sau c np vo mt ng
vi mao mch. ng c t trong mt thit b c bit, v c bao quanh bi cc si
quang, cc si ny s bt c tt c nh sng c pht ra khi thuc nhum c kch
thch bi thit b laser. Thit b ny cho php pht hin PrPSc vi nng thp hn
cc thit b khc, y nhanh c tin kho nghim.
Trang 40
Nhm 8
c t ngun gc t nhin
Vitamin A Vitamin A l mt cht dinh dng quan trng c tm thy trong
thc vt v ng vt cho thy vitamin A l ngun thc phm in hnh . Vitamin A
cn thit cho vic tng trng bnh thng v tm nhn ng vt. S thiu ht vitamin
A c th dn n m m, suy gim pht trin xng trong gii tr, v cc bnh ca
mng, mi, hng, v mt. Bng 2.1: Mt s ngun vitamin A
VI.1 Cu trc ho hc Vitamin A l mt tan trong cht bo, mu vng sng,
kt tinh nh hnh kim.
Hnh 2.6: Cu trc ca vitamin A Kh c th xc nh do tiu th qu mc cn
thit cc cht vi dng bi v bt k mt thc phm no cng c th gy ra cc phn ng
c hi khi c tiu th qu mc.
Trang 41
Nhm 8
c t ngun gc t nhin
Do ,d c gy ra cc phn ng c hi cho c th nhng vitamin A vn khng c
xp vo cht gy c. VI.2 Biu hin v Liu lng Cp tnh: Ni chung, vitamin A
l c hi i vi con ngi mc 2-5 triu IU (mt IU tng ng 0,3 mg vitamin
tinh th tinh khit A (retinol) hoc 0,6 mg -carotene. Gan gu bc cc l
rt giu vitamin A v c t nht mt trng hp nhim c cp tnh do tiu th ca
gan A giu vitamin, c bo co nhng nh thm him Bc Cc v ch ca h. n phi
gan gu bc cc gy ra sng au di da. Trong cc bo co, trng hp nut gan gu
Bc cc cn gy ra au khp v kch thch, kh mi, chy mu mi, v cui cng l ci
cht. Ngoi ra, cn c mt bo co rng mt ng dn ung gn 30 triu IU vitamin
A trong gan c bn, c cha ln n 100.000 IU / g vitamin A, v phn nn v
nhc u d di tp trung trn v mt, chng mt, bun ng, bun nn, v nn ma
trong 12 n 20 gi tip theo b v sng hng ban v bong trc da. Bng 2.2:
Liu lng n vo cho php ca vitamin A theo tui
Mn tnh: Ng c mn tnh vitamin A gy ra bi vic tiu th 1000 mg (khong
3000 IU) /kg trng lng c th /ngy. Cc gi tr khc nhau ty theo ngun
cung, nhng y l gi tr thng c cng nhn. Du hiu ca ng c mn tnh bao gm:
nga, kh da, bong vy, mt cm gic ngon ming, nhc u, ph no, v xng v au
khp. Trng hp nghim trng ca hypervitaminosis A c th dn n tn thng
gan, xut huyt, v hn m.
Trang 42
Nhm 8
c t ngun gc t nhin
PH LCPhn b trong 1 s loi thc vt Ngun Nhng yu t gy c
u nnh v nhng sn c ch Trypsin, phytohaemagglutinin, khng nguyn,
phm t n lipoxygenase, goiterogen, saponin, estrogen, phytic-acid v
oligosaccharides (NSPs 30.3%) Groundnut v nhng sn c ch Trypsin,
goiterogen, tannins, oligosaccharides v phm t n lectins
M tt, hay b ht v nhng Goiterogens (thioglucosides or
glucosinolates), tannic acid, sn phm t n erucic acid, sinapine
(cholinester), pectins and oligosaccharides (NSPs - 46.1 %) Ht cy
rum v nhng sn Yu t estrogen, hai loi phenolic glucoside (to v ng)
phm t n Ht hng dng v nhng Chlorogenic, quinic-acid v x (hp cht ging
tannin) sn phm t n Ht m v nhng sn phm Phytate (5g/100g) and
Oxalates (35 mg/100g) t n Ht lanh v nhng sn Linamarin (cyanogenic
glucoside), antipyridoxine (Linatin) phm t n Ht cy bng go Ci da kh
Ht cy c v cht nhy (mc HCN 10-300 mg) Tannins, tyrosine v acid bo c
vng cyclopropene X (mannans) v estrogen Fibre (galactomannans
-(1,4)-D mannans) v lp v cng
Ht cy bng v nhng sn Gossypol (hp cht ging phenol),
cyclopropenoid fatty phm t n acids, tannins
Nhng sn phm t ht Guar gum (18-20%), yu t khng trypsin v vitamin
E
Trang 43
Nhm 8
c t ngun gc t nhin
Guar tetragonoloba)
(Cyamopsis
Ht thu du v nhng sn Ricin (toxalbumin)-Phytohaemagglutinin phm t
n Ricinine (Toxic-alkaloid) Ricinus allergen (Protein
Polysaccharide) Ht Neem (Azadirachta indica) v nhng sn phm t n
Bitterness Limonoids Triterpenoids Bitter principles:
Protomeliacins, Limonoids, Azadirone, Gedunin, Vilasinin and
Secomeliacins Nonisoprenoid polypenolics-Flavanoids, Tannins and
coumarin viz. Nimbin, Salannin and Azadirachtin Dried seeds
limonoids 0.001 to 0.1%, Azadirone, 0.45% and Epoxy Azadirone,
0.72%, Azadiradione, 0.7% and Salanin, 0.95% Mahua (Madhuca
latifolia) Mowrin (Saponin) v Tannin
Karanja (Pongamia glabra) Cht bo lin kt vi cc yu t gy c
Karajnjin v Pongamol (Flavanoids) (NSPs 38%) u Lupin Quinolizidine
alkaloids, pectins, oligosaccharides, Mangan cao, saponin. u H lan
Ht cy cao su Bp c ch Protease, tannins, Lipoxygenase v lectins
Hydrocyanic-acid (20-40mg/kg) Selenoamino acids (seleniferous)
Estrogen (mouldy) c ch Trypsin La m Go La mch en Tyramine, c ch
Trypsin, NSPs (11.4%) Estrogen v haemagglutinins c ch Amylase v
protease v NSPs (13.2%)
Trang 44
Nhm 8
c t ngun gc t nhin
Yn mch Triticale Mt vi ging la mch Mt vi ging la min Go nh bng v
cm go Chunies
c ch Amylase v estrogens c ch Trypsin v chymotrypsin (NSPs) -
glucan (NSPs 16.7%) Tannins c ch Trypsin v yu t khng thiamin Yu t
khng tryptic
Ht Sal v nhng sn Tannic acid (tannins) phm t n Bt khoai m
(Cassava) Cyanogenic glucoside (HCN 1000 3000 mg/kg DM)
Nhng sn phm t c, tht Gizzerosine v histamine (Biogenic amines)
(vi nguyn liu b h hng)
Trang 45
Nhm 8
c t ngun gc t nhin
TI LIU THAM KHO Ngc Lin. 2007. Th th acetylcholin v s truyn xung
thn kinh. NXB i hc quc gia H Ni, Tr 43 53. Dng Thanh Lim, 2008. Ng
c thc phm, nhng bnh truyn qua thc phm, nhng thch thc v s an ton thc
phm. B mn Dinh Dng Khoa Chn nui Th Y Trng i hc Nng Lm
http://www.fao.org/docrep/ARTICLE/AGRIPPA/659_en-10.htm
http://www.fao.org/docrep/X5415E/x5415e01.htm
http://www.fao.org/docrep/T0207E/T0207E08.htm
http://vi.wikipedia.org/wiki/%C4%90%E1%BB%99c_t%E1%BB%91_th%E1%BB
%A7y_s%E1%BA%A3n
http://www.toxinology.no/Researchareas/Planttoxins/tabid/4365/Default.aspx
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