NGHIÊN CỨU TÁC DỤNG CỦA VANADIUM VÀ CHITOSAN CHIẾU XẠ LÊN CÂY HOA CÚC
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (13.91 MB, 89 trang )
BỘ GIÁO DỤC VÀ ĐÀO TẠO
TRƯỜNG ĐẠI HỌC ĐÀ LẠT
TRƯƠNG NỮ THANH TÂM
NGHIÊN CỨU TÁC DỤNG CỦA
VANADIUM VÀ CHITOSAN CHIẾU XẠ
LÊN CÂY HOA CÚC
CHRYSANTHEMUM INDICUM L.IN VITRO
LUẬN VĂN THẠC SĨ
NGÀNH: SINH HỌC
ĐÀ LẠT - 1999
no GIAO DI)C vA BAo TAO
TRUONG BAI HOC BA LAT
KHOA BAo TAO SAU BAI HOC
III
TR lICiNG Nfl THA 'H TA M
NGffiENCUUTACDl)NGCUA VANADIUM vA
CffiTOSAN CffiEU XA. LEN CA Y HOA CUC
CHRYSANTHEMUM INDICUM L. IN VITRO
c%-q
Chuyen ng,tnh : SINH L Y THljC VAT
s6 :02
M5
LU,\N AN TH~C SY KHOA HOC SINH HOC
,'- --- - =
-:
-----~-
'_
• _.'
, l • -j;
i
~:
~:. i.'
_.•-\ 'I"
r
•
"
L' i
;"
I pI"" .• DO" ":hTil
Qa
r
L""'··:a>· ~ . . . r~:.~~
Can bi) hudng diln: Iyrs LE XUAN THAM
Vi¢n
ghicn
CU'lI H~l
nhan
E>al~t
I'GS-I'TS MAl XUAN LUCING
Truong El~i hoc Elal~t
Dalal· 1999
~ii'i
dm on
Tili cI*i tNrn cam an cae Thily. CIl ,po kroa £lao 0<'0 Sal V*"c.
Truar.g £1", f-Qc V~o ail "tnJy~n Uv rhlr.g !:itn wc quY btu em Wi umg
eu50 wi gan f-Qc o'ili oru<7r.g
cam
man
Tili a~ ~o
an PTS LP ,.a, Thiim, V~n rq;en rou H
~ alf Wi ma,
I.J?1 an
wam
TIIi clr1g cam an Dr. Tan1
TI1U1<3 oam rq;en rou cay tll,rc philm Val<1o.
TI1U1<3 oam CIlr.g ~ sm f-Qc NIlr.g nq;ep Val<1o.
Cae Am, Oi pWr.g 5m f-Qc pror.g "" ail 0,,0 ,,~u ~n 108'0 rtlEio aif Til;
ohlc f1?n a~ oE;
Con ,on bay t-O 0r.g hto an sau sk Wi Ba fk va cac ai1 cfi em umg
Gia aim ha bSn ail dam cm con
rhlng olnh cam quY bau. allng v~n va giJp
"If con "if ""0 "uqc ks'o qua nhu il'Jm nay.
MI)C LI)C
Lili md dilu
Muc luc
~
~
~
~
PHAN THU NHAT. TONG QUAN
Chuong I. Polysaccharide va ho u I tinh sinh hoc
I. Chilopolymer va hoal linh sinh hoc
II. Oligosaccharide va hoaltinh sinh hQc
Chuong II. 6 nhiem vanadium va diic tinh tren !huc val
I. Vin M 0 nhiem kim loai nang va doc tinh tren thl1'C vat
II. Nguy co 0 nhiem va hoatlinh sinh hoc vanadium
PHAN THU HAl. ~)61 TUqNG
vA
PHUONG PHAP NGHIE
2
2
8
23
23
25
CUU
I. 86i lliong nghien cLru
II. Phuong phap nghien CLlu
PHA
32
36
THU BA. KET QUA THVC NGHI~M
Chtlong III. han gi6ng vo tinh in vitro cay hoa cuc Chrysatllhemum
inc/iewn L.
I. Khdi dong milm
II. Giai doan nhan nhanh
III. Dm hii!u anh hlldng clla IBA
IV. Dm hii!u anh hlldng cua NAA.
Chllong IV. Khao sal anh hlrong Clla chitosan chi"u xa Jen cay hoa Cllc
Chrysanthemum indiewn L.
I. Khao sat anh hudng cua chilosan chi"u Xu li(\u 200 kGy.
II. Khao sat anh hudng ctla chilosan chi"u Xu Ii(\u 400 kGy.
III. So sanh tac dung Clla chilosan chi"u Xu 200 kGy va 400 kGy len
sinh tnrdng va phat lri6n diy hoa cue.: Chrysanthemum indicum L.
Chuong V. 86c linh vanadium va tach dung cua chilosan chi"u Xu li(\u
200 kGy len diy hoa cue Chrysafl1hemum indicum L.
I. Khao sat anh hlfdng cua vanadium.
II. Khao sat anh hlfong k"l hop chilosan chi"u xa li(\u 200 kGy va
vanadium LG 50.
39
39
41
43
46
49
49
51
55
59
59
63
PHAN KET LUAN
68
Ta i lieu lham khan
71
UiI MaDAU
6
nhi6m kim loai nang moi trt(ong dang tra thanh m6t vfin d6
quan tTong tren toan du. Nguy cd 0 nhi6m vanadium, rna chu ySu du<;je
thai ra 111 cac nha may san sinh nang lu<;jng (nhi';t di';n, ...) va eong
nghi';p (cong nghi';p m~, luy';n kim, ...) dang ngay dng gia tang va gay
ra nhi6u nguy hicim d6i vdi suc khOe con ngl(oi.
C6ng d6ng chau Au,
vanadium dl(<;jC thai ra lii' cae nha may nhi';t di';n diing than khoang
13.000 tfin, tTong d6 e6 1% (khoang 144tfin) du<;je thai ra dudi dang khi
thai, chi dung sau Pb (191,5 tfin) va Zn (341 tfin) (Sabbioni va e6ng slf
1984).
a
a
Lu<;jng vanadium cao trong khOng khi thuong t~p trung nhi6u cae
khu cong nghi';p. Th~t v~y, trong khi ham Il(<;jng vanadium trong khong
khl
I~e dja thl(ong la 0,5-2 ng/m' thl giln day, ngl(oi ta da ghi nhan
du<;jc a khu v\(c nong thon cua Vl(dng qu6c Anh, Canada va m6t so'
thanh ph6 IOn cua My, ham lu<;jng vanadium trung blnh hang nam Ien
dSn 75 ng/m' va
vai khu eong nghi';p, ham Il(<;jng nay len dSn
2000 ng/m', cao hdn gfip hang tram ngan liln ham lu<;jng vanadium trung
blnh hang nam Nam ctrc (1-2 pg/m') (Edel va SabblQni, 1988).
a
a
a
Hi';n nay, con ngl(oi cung nhl( d6ng, thue v~ttren hanh tinh dang
phai dtrdng dilu va hang chju m6t Itr<;jng IOn vanadium 0 nhi6m tTong
moi trtrong. Vi';c xac dinh d6c tinh vanadium tren thtrc v~t la di6u dn
thiSt, tuy nhien chua e6 m6t kSt lu~n th6ng nhfit nao xac dinh d6e tlnh
ella vanadium lren lh~(c v~t.
Trtrde nguy cd 0 nhi6m kim loai nang d6, nhi6u nha khoa hoc
eung nhl( cac cd quan nghien eau co' ging tim ra cae giai phap khie
ph~e 0 nhi6m. Nam 1972, Muzzarelli va Turbertini d. phat hi';n ra
chitosan la m6t chfit khang x~ cao va dl(oi tac d~ng cua bac x~, kha
nang bit kim loai cua chitosan voi cae kim lo~i e6 ho~ttlnh ph6ng x~
viin khong thay d6i. Eiden va C6ng Sl( (1980) thfiy ding chitosan c6 thci
hfip thu Pb va Cr m~nh hdn chitin. Maruca, 1982 dil li';t ke hang loat cae
nghien cau c6 lien quan dSn kha nang hfip thu cae kim lo~i ni:;ng (Cd,
Cu, Cr, Zn, Hg, Pb...) len chitosan. Peniche-Covas va C6ng slf (1992) d.
tim ra cac lOp hfip thu Hg du<;jc t~o ra trang qua lrlnh hfip thu Hg tren
chilosan. Cac nghien cuu ctia cac tac gia neu tren da cho IhiCy kha nang
hiCp lhu m(>t s6 kim lo~i nang ctia chilosan chie'u xa.
Ngoai ra chitosan con dll~lc cho la co kha nang di~u hoa sinh
trllong, thuc diiy tang lrllong lhl!C vat va dll<!c xem Iii m(>t trang cac tac
nhan gay nen cac phan ung tll vr; 0 lhl!C vat (Kiem Tran Thanh Van vii
c(>ng sl!, 1984, Albersheim va Darvill, 1985).
Chung loi cho rhng viec ch(lng minh dl/<!c m(>t chiCl bao g6m nhi~u
lIu di€m (giiii d(>c kim lo~i nang, lhuc My lang trllong thl!C val, v.v) Iii
m(>l viCn d~ he'l s(lc 19 thu va dn lhie't cho khoa hQc ding nhll d6i vdi
nganh nong nghiep va bao ve moi trllang. Do do lrong nghien CUll nay,
chung toi tie'n hanh nghien cuu tac d~ng ctia vanadium va chitosan
chie'u x~ tren cay hoa cuc Chrysal1lhemllm indiclIm L trong di~u kien in
vitro.
Mac dii da dilnh thai gian lhich dang nhllng khong lranh kh6i m(>t
s6 J6i viin co th6 con sOII~i lrang luan an. RiCt mong nhan dl/\1c sl! gop 9
clla qu9 Thfty Co va quy vi quan tam d€n viCn d~ nay.
Dil 11;11, {hang
3 /lam 1999.
Tac gid
PHAN THU NHAT
,:>
TONG QUAN
Chuang J. Polysaccharide mimg va lac di)ng cita chLing len 0wc V(lf
2
CHUaNG I
POLYSACCHARIDE MANG
vA TAC DONG CVA CHUNG LEN THI,fC VAT
I. Polysaccharide mang va tltdng hie cua chitopolysaccharide
I. Polysacchride mang
Trong ll1 nhien, c6 de'n 90% IMnh phdn la dc polysaccharide lan U!i
lrong mang Ie' bao so clfp thl1C v~l b~c cao. Cac polysaccharide nay bao gam
cac dltCfng don gqi la monosaccharide lien ke'l vdi nhau b1ing lien ke'l
glycoside dac ullng. Phdn Idn cac monosaccharide Ian lai u'ong lhanb Ie' bao
la cac pentose hay hexose. ciu truc glucose la cau truc di~n hlnh cua tit ca
cac monosaccharide duqc tim thay trong mang tt baa thl.!C v~t. Theo cach s~p
xe'p cua H va -OH lien ke'l vdi C 1 va C, lrong ph.n tlr dl(Cfng theo dang u hay
~ ma la c6 dc dang glucose khac nhau. Lien ke'l glycoside n6i cac u hay ~
glucose 1<,) i vdi nhau
t~o
ra st! phong phli cha cac polysaccharide. Vi dl;l hai
ph.n Ilt dl1Cfng gam 6 carbon nhlt glucose c6 the' dl.tOC n6i theo 64 each khac
nhau, 3 ph.n ttt dltCfng khac nhau c6 thi! dlt'!C n6i theo hon 1000 cacho Mqt
polysaccharide c6 thi! bao gam hang tram, hang ngan lh~m chi hang u'ieu
monosaccharide. Ngaai ph((c t~p v€ cau truc, cac polysaccharide thanh te' baa
con ph(tc t~p hon do Slt hien dien cua eac nh6m kh6ng phai la cllu truc dl(Cfng
(non sugar) nlHt melhyl elher, methyl hay acetyl csler u'ong ciu truc cua
chung (Albersheim and DarviII, 1984) II I I. Do d6 dc polysaccharide mang
rilt da dang va phong phu ve chung loai.
Trong 90% cac polysaccharide du tao nen mang le' bao so cllp lhl c6 it
nhill la 8 loai polysaccharide khac nhau. Ngl(Cfi la di1 xac djnh chfnh xac 6
trong 8
la~i
polysaccharide d6 Hi.: homagalaclUronan, rhamnogalactuwnan I,
rhamnogalacturonan II, xyloglucan, arabinogalaclan, glucuronarabinoxylan
[II J.
hl1 v~y, trong mang Ie' bao thl1C v~l b~c cao, acid galacluronic (pectin),
glucan va xylan la chu ye'u (Ryan and Farmer, 1991, Aldington and Fry, 1993,
C6le and Hahn, 1994) [64, 12, 22J, trong mang Ie' bao c6n !fling, giap xac,
nilm chu ye'u la chilin va chilosan (C61e and Hahn, 1994, MalSuhasbi and
Kume, 1997) [22,54], con lrong cac loai lao bii!n chu ye'u lai la alginat (la eac
poly guluronal va poly mannurona!) (Gacera P., 1988) [29J.
Lu(in an
111(IC
sy - Tru(/IJg Nil Thanh Tcim
Chuang I. Polysaccharide milllg va ldc dijng ('/;a cluing Jen lhl/e v(il
CRl"~T ...CEl)l'S
SllEI L.1:"SECT SHELL IC:-'Cl
PLANTS
,
J
D~'D~t{],~,O
I
,
;
•• ••
0
0
,
~ l-->~ I-~O 1-.~O·P'TliJ
1
,,
,
I
A,-,Ah'A
,
1
1
H~pl.,p...~lu.-o,iJ~
1
I
A'-'A
I
'V
CI}"C"p.;pliJ",
Ol-->(~OI
.....)... O
<>~"<>,~"<>
Olig,lClllhlSan
D~-,IUCO$~
•
Xr1o,I\lcan l"OfIa<;anh.ariJc
. 1 ..... t~.HI. ...
Oligochilin
0
p-,lua.>",)nl;n<;
01igoga lact\Jrt'n iJ,'
OlJ·N'~'·CI)·I.,lucosamill
f:YJ.m;oono'I":
.Ao.·marmo«'
6
I
~
)
;
,
A
J
Ohf(Ji-'OI~'OI-'O ... -.2 ... 1.....
3
a·gabrluft>llidc add
•
~"illil"lo""
.0.-")],.
'7
o.-fu,o$e
Hinh aI, Cong tJllk ('c'tu l{tO mQI SO' polysaccharide mling It bllO
(Francois
Co,e wi AliclUJeI G. Hahn,
Chilin la poly N-acclyl
p,
/994) {/9{.
D gluco,aminc lien ke'l nhau bhg lien ke't
p,
1-4 glucosidc va dUn xuill N-dcacelyl clia chling la chilosan (Randle va
Morgan, Biochcm. J., 61, 586, 1955) (Iheo Izu111e va Ohtakara, 1987) (401.
Chung Utt(jc lIng dung long rai Imng y Ie' va ,rong cling nghiep nhtl la m"t
chilt lieu hoal dong sinh hoc (Malsuha,hi va KU111C, 1997) 1541. fliic bi,,1 VI
chitin va chitosan d6u cO tinh Ilfffng IH,fp sinh h(,IC, tinh suy thoai sinh hQc va
khilng doc nen chung to ra thich h
M
lIng dung trong IInh vtlc dtl(jc phim
(che' (<;10 ra cac t:h{{ ph5m Ir! na'm trong y h{.)c. mung hay kem chua bong, lam
mall lanh ve't thl(
thll, v.v). Chung con dtloc dl,ng lam ch:i, cel dinh enzyme, lam chill trung gian
van chuyGn dtl(je Ii"u: vilamin PP, B" earcine, lam ehilt ha'p thu tlOng cling
nghi"p nhu"m,
d~l,
dung lach cae phlrc hllp hflu co long va dung trong cling
ngh" che' lao my ph am (VO Tiln Thi¢n et ai, 1998; Mllzzarelii, 1972; Pham
Thi Ha et ai, 1996; Urilgami, 1998; Sathirakul and Buppa, 1998; Hudson,
1998; Vachoud cl ai, 199X; Srikumlalhong cl ai, 1998) IX, 58, 4, 83, 69, 38, 84,
Lu(ill an
TJ/(IC 5)"; -
Tn((Jllg Nil Thanh ,[,iim
Chuollg I. Polysaccharide mimg
va tdc dQllg ciia cht,ng lell thlfc w;it
4
73]. Chung dLiqc (rng dl.lng lrong nong nghi¢p lam chUt kich lhich tang tniOng
cho cay, bao ve moi truong (thu h6i kim lo~i nang, protein,v.v), lam ChUl bao
quan thl!c phii'm, rau qua va hoa qua tUdi, lam mang mong an dudc d€ bqc
banh kyo v. v. (Chau Van Minh, 1996; Fichaux, L. et ai, 1998) 11,281.
Pectin la nh(rng polymer cua acid galacluronic dudC n6i bOi lien ke't
a-( 1,4) glucoside. Pcctin la chii"t c6 ch(ra polygalacturonic acid dLrqc mClyl h6a
100%. Acid pectinic la ChUl dudc melyl h6a thUp hdn 100%. Acid peclic la
acid polygalacturonic hoan toan khong ch(1a nh6m metoxyl. Trong thLic v~l,
pectin thtrong lien ke't vdi cellulose 0 vach te' bao dudi dang pMc hqp. Khi
thuy phiin hoan toan peclin, la se thu duqc acid galacturonic, acid
polygalacluronic, galactose, arabinose, rhamnose va sorbose (Deuel and Stutz,
1958) (theo Aldington and Fry, 1993) 1131. Pectin giup cho thanh te' bao vllng
ch~c, deo dai dac bi~t la 0 cac mo khong c6 mach gll (lignin) va cac qua chin.
Chinh VI v~y, khi cac tac nhan gay b~nh la vi sinh V~l hay nUm tUn cong vao
le' bao thl.tc v~t, chung thltong tie-t ra cac enzyme nh!1m vao nwc lieu adu tien
la peclin (Pagel va Heilefuss, 1990) (theo Messiaen va Cu[sem, 1994) 156J.
Pectin dtrdc diIng nhi6u U'ong ky ngh~ san xuUt m(1t, keo, v.v nho kha nang
tao gel cua n6 khi c6 mal acide va dtrong. Pectin gill vai lrO quan U'ong lrong
qua lrlnh lam chin qua. Khi qua dang phat lri€n, prolopectin phan tan 0 thanh
te' bao va chie'm ly I~ cao. ~)c'n luc qua b~t dilu chin, protopcctin chuy€n diln
sang d':lllg pectin hoa tan dltdi u1c dl.lIlg ella d.c acid hrtll cd va enzyme
protopeclinase lrong qua [13J.
Alginat la mu6i cua acid alginic, la mQl polysaccharide c6 nhi6u lrong tu
nhien, chu y€u dtiqc chic'l lil' tao nau do Standford phal hi¢n ra nam 1881.
Alginal bao g6m ba lo~ i kh6i (block) u'ong m~ch polyme, CLI th€ la:
polyguluronal (poly-G), polymannuronat (poly-M) va co-polymer cua poly-G
va poly-M (poly-GM) lien ke't ngiiu nhien lrong chulli mach. Alginat dtrqc (1ng
dqng rQng rai trong cong nghiep lhl!c phii'm va d6 u6ng. 6 du'qc diIng lam
chUt 6n dinh bqt (trong bia), ch6ng lach pha (trong kem), chUl6n djnh dQ nhdt,
tao gel, (ing dung lrong cong nghi~p dLrqc phii'm va my phii'm, lrong cong
nghi~p in va Him gi£1 th~ cd djnh cac hO':lt cha't sinh hQc (enzyme, te'
bao,
v.v.),
(1ng dung trong cong nghe len men, v.v. (Gacera, 1988) [29J. Alginat cung c6
anh hLiOng tich cuc len su tiing truOng, keo dai ri\, ch6i 0 thuc vat (Yonemolo
et ai, 1993, Natsume el ai, 1994, Tomoda et al,1994) [94,60, 79J.
Luijll an Th(lc
S)""f
+
Truong Nil Thanh Tdm
Chuang l. Polysaccharide mang va
laC
GQng diu cluing len Ih{/C WJI
5
2. Tac d()ng cua chitopolysaccharide
SUOl nlQl thai gian dai, cac hydralcacbon chi dl(qC xem
la c6 vai lro nbu
dc phan tlt du trll nang luqng hay cac phan ttt cd ban diu truc nen thanb te
bao (John, M. et ai, 1997) [421. Tuy nhien, ttt khi Brunei, 1951 phal hien cae
hydrat carbon tren be mat mang t6 baa hling du (erythrocyte) dn thiel cho
vi¢c giln kel va xam nhi!p clia virus cum (Ryan, 1988) [65[. Cae
polysaccharide duqc chu y va cac nghien c((u v6 anh hudng cua chung cung
cac dfin xui'll cua chung lron cac doi luqng sinh V~l (vi sinh V~l, nam va thlfC
vi!l bi!c eao) dudc tien hanh va da phat hi~n ra nhi6u viln
M 19 thu.
Tntdc hel, chilin va chilosan c6 kha nang d6 khang do'i vdi vi sinh vi!l
(Allan va Hadwiger, 1979; Kendra va Hadwiger, 1984; Fang el aI, 1994;
J-1adwiger el ai, 1994) [431. ChilOsan con c6 anh hu';ng den su sinh lru';ng clia
nilm Idn, nilm men. Lqi dong lich chill nay, nguoi ta da tach chilin va cbilosan
lU v6 lam, ca mltc d6 lam chill khlt nilm trong thuc phllm (Sugawara, 1993;
Ghaouth et ai, 1994) (thea Matsubashi and Kume 1997; Watanabe, l ' et ai,
1998) [54,911. Mdi dily, 1998, Vii Thi NgQc Thanh (E>ai hQc Y khoa Ha ni)i)
va Nguyen Thi NgQc Tu (Vi~n H6a hoc) sau khi khao sat lac dung khang
khulln, kbang nilm clia chilosan da ket lui!n chilosan e6 tac dung khang kbulln
kha to'l lren ba chling vi khulln Staphylococcus aureus, Escherichia coli,
Pseudomonas aeruginosa vdi nling di) (tc ch6 lo'i thi6u tu 1/1000 den 2/1000.
Chilosan cung c6 lac dl.;lng khang flam kha lOllron flam men va nam da vdi
nling di) (tc che lo'i lhi"u Ill' 2/1 000-4/1 000. Ngoai ra, chilOsan Otrqc san xuatlu
dc loai v6 lam khac nhau c6 lac dung giln gio'ng nhauva khong thay d6i sau 6
lhang .; dang dung dich 4% lrang dieu ki~n baa quan blnh thuong
(Vii Thj gQc Thanh el ai, 1998) [9[.
C6 the kha nang d6 khang vi sinh vill clia chilosan c6 lien quan den kha
nang hQal d(jng cua cac nh6m ch((c lrang phan ll'( va lrQng Il(qng phan ll'c
Erikson va Hardin (1987) va Uchida (1988) cho r~ng chilOsan trQng luqng
phan ll'( cao c6 chilc nang nhl( 13 OlQl chal khang vi sinh v~t. Tac gia cho rhng
chilosan c6 tac dung lien ket mi)l trang hai nh6m ch(tc clia n6 la nh6m amino
hoac nh6m lien k6l hydra lrong phan ttt M tao lien ket giua chitosan va cac
polymcr n~ll1 ngoai liS b,1O l~O ra SIt llrdng lac nnh di~n lren be mat le baa.
Nam 1988, Uchida cong bo' hoal tinh khang vi sinh vill cda chilosan phu thui)c
nh6m amino lrong phan lil' va lac gia xac djnh chilOsan dltqC thliy phan b~ng
enzyme'; 5% c6 cao hdn so vai chitosan khong dudC thuy philn (thea
Matsuhashi and Kume 1997) [541.
Luijn lin Th(lc sS'i - Tru(mg Nli Thanh 1(lm
Chuang I. Polysaccharide mimg
va Ide dQng ella cluing len ,hife ,,(il
6
Nam 1998, Tsai Guo-Jane va Su Wen-Huey khi lach chilosan tIl' vo lOrn
v,
d€ I~i dl:Ing tinh khang sinh v~t lrong cong tac bao quan ea xac dinh kha nang
khang khuiin cua chitosan lang khi muc deacetyl h6a chitosan tang. Cae tac
nhan ben ngoai ding lien quan dc"n tinh khang khuffn cua chitosan. Cac muoi
c6 kha nang t~p ph((c vdi ehitos3n lam giam kha nang (i'c che' vi sinh v~t clla
chung. Kha nang (Ie che' vi sinh v~t tang trang khoang ul' 4-37' C theo chi6u
Hing clla nhi~t dC). DC) pH acid lam kha nang lic ehe- vi sinh v~t cua chitosan
hi~u qua hOn. Cae cation thea th(i' tV 8a 2+, Ca 2+, Mg 2+, lam tang khcl nang ((c
ehe vi sinh v~t. Cae lien H:'t eh60 gi[(a poiyeation cua chitosan va anion cua
a
b6 mal vi khuiin c6 lh€' lam lang lfnh thilm cua mang dll(lc the' hi~n viec thai
glucose va laclatedehydragenase tIl' te'bao (Tsai, J.and Su, W., 1998) 181J.
Tac nhan ph6ng xa c6 anh hllang de'n Hnh chill h6a lji cua chilOsan. Buc
x~ gamma e6 Uie dl.lng lam giam khJ nang dong tl,l, dit;n lich be m~lt, va d9
nhdt cua chitosan. Tac nhan ph6ng xa con lam tang Iliong glucosamine giai
ph6ng khoi chilosan do sll phan gfai chitosan
dang dung dich. Tfnh chill
dong t~ Clla chitosan giam do hai ye'u t5 quan trong anh hllang de'n lfnh dong
tu la di6n tich b6 mal va trang IlI(lng phiin tl~ giam (Kume, T. va Takehisa,
M., 1982, 1984) 146, 47J. Sau 10 ni,m, 1992, P. Ulanski va .I. Rosiak nghi~n
a
cuu nhung bien d6i cd ball ella chitosan khi chieu x~ lieu cao tren may gia toc
di~n tu, tac gia xac nh~n hi6U qua phiin dl ph6ng xa tao ra cac nh6m phan tu
11I(lng nho (chinh Iii oligosaccharide) vii khJng dinh kha nang hilp thu kim lo~i
lang khi lrang 11I(lng phan tt~cac chilosan giam (Ulanski va Rosiak, 1992) [821
(Kha nang hilp lhu kim loai cua chitosan da dlloc Murazzelli khJng dinh 1972)
1561. am 1997, Matsuhashi va Kume nghi~n cuu anh hlldng cua chitosan
phan giai b~ng chieu xa cac 1i6u khac nhau I~n sll phal triin E. coli vii ke't
a
lu~n tfnh khang khuffn c6 lien quan den trQng Il(~ng philn tic
ghien cau cho
a
lhily, chitosan dtlOC chie'u xa
li6u 100 kGy (Ic che' m~nh Sl.t ph at lri€'n cua
E.coli. Do d6, c6 lh€' vdi li6u chie'u ill', chilOsan dUoc phan giai thanh cac
phan doan nho c6 U'ong Iliong phan tu lhich hop cho vi6c uc che' hoal di)ng vi
khuiin (Matsuhashi vii Kume, 1997) 1541.
Nam 1998, ShigchiJO Hirano va ci)ng Stl kham pha r~ng khi XLI lji chilin
va cac diin xuilt cua n6 I~n te' bao, callus va hat lua thily xuilt hi6n cac d6ng
phan (isofnrm) cua chitinase vii xac djnh lrinh ut s~p xe'p cua nh6m cu5i
N-amino acide U'ong d6ng phiin chitinasc (fll(lc lao ra do hoat di)ng ttl bao v6
cua chung. Ba d6ng phiin (A, B vii C) cua chilinase dli dll(lc phal hi~n trang te'
bao, callus va hat sau khi XLI lji chitosan. Trinh ltl s~p xe'p cac nh6m cu5i
N-amino acid cua cac d6ng phan nhll sau: trong N-Glu-Gln-X-Gly-Ser-GlnAla-Gly-Gly-Ala-Leu-X-Pro-Asn--- d6i vai d6ng phan A vii B vii trong
LuQn an Th(lc sS'i - Trucl11g Nu Thanh Tam
Chuong I. Polysaccharide mimg vil/dc dQng clla cluing len
/h~(c \/(1/
7
N-G Iy- Asp-Ile- Ala- Val-Tyr-Trp-G Iy-G In- Asn-G Iy-Asp-G lu-G Iy-Ser- Lcu-AlaX-Asn-Ser-Gly-Leu-Tyr-Ala--- d6i vdi d6ng phan C (X: khong dlraC phan
lich). Qua d6 ta thiy te- bao thtlc vat c6 chlre nang tlf bao ve d muc d(lte- bao
bhng cach giai ph6ng hang lo~t cac protein c6 quan h~ vdi tac nhan gay b~nh
bao g6m ca chitinase (Hirano, S.. 1998) [341.
Chitopolysaccharide con c6 m(lt so' tac dung khac.Chitosan mang lai Iqi
feh cho cong vi~c tr6ng rau. Nam 1998, Chin-Fung Li va Jia-Cheng Wu cho
thiy chitosan c6 hi~u qua dbi vdi vi~c k.feh thfeh nay m~m d m(lt so' lo~i rau:
xa lach, su la, b~p cai Trung hoa, rau Mn, v.v. va chi c6 tac dung vdi cac loai
hat c6 Idp vo mongo Chitosan con c6 tac dung kich thfeh tang tntdng thtlc v~t
ln311 Brassica ehinensis h.cv. Ching-geeng. ChiLOsan con c6 lac dl.lI1g ngan
nglia cae b~nh gay bili Cercosporella brassicae (Li, c., F., va Wu, c., .1.,1998)
1481. Chitin va chitosan c6 th& Sl~ dung lam chit mang d& co' dinh enzyme va
lam tac nhan kfeh thich phan ung bao ve (phytoalexin)(elicitor) lfong nuoi ciy
t6 bao (1998, Huang-Shih-Yow) [371. Chitin va chitosan con gay tie-t L-DOPA
(3,4 dihydroxyphenylalanine) U'ong nuoi cily huy~n phu te- bao Stizolobium
hassjoo vdi Slt trq giup ella acid ascorbic [50].
Ngoai cae kba nang khang vi sinh v~t, kich thich nay mh, d hat, kich
thich tang lftldng, phan ling ttl v~ vdi tac nhan gay benh d thltc vat, lam chit
mang, V.V. Do kha nang c6 th& t~o lien ke-t vdi cae anion ben ngnai phan tr'i
nen ehitosan con c6 kha nang hip thu kim loai nang t,)O kha nang thtlc thi eho
vi~e ung dung ehitosan trong cong nghe loe ntldc thai kim loai, bao v~ moi
trtlong (Maruca, R. va Wightman, 1982) [531.
Th~t vaY, tll nam 1972, Muzzarelli da quan tam de-n vin de nay. Dng
lhl.tC hi~n cae nghien c((u va khii nang b~t kim lo~i n~ng clia chitin va
ehitosan va cong b6 ke-t qua v~ kha nang hip thu Hg, Co, Ag, Mo, Ir, Cs, Zn,
Fe, Au, Sb, va Cr clla chitin va ehilOsan. Nam 1978, Hauer dlla ra thi nghiem
v~ lien quan gili'a ehitosan va nlQt so kim lo~i n~ng g6m Cd, Cr, Cu, Pb va Zn.
Masri va Randall, 1978, phat hien kha nang cae ion kim lo~i nang c6 tb& dtlqc
tach loe khoi cae phe-li~u thai ra tll cac nha may, cong xlldng nho chilOsan.
Nam 1979, Kurita va c(lng Slt xac djnh ion Cu(11) va Hg(ll) dllae hip thu bdi
chitin va cae dfill xuilt cua n6 nho cae nh6m amino trang eill! true phan ltl'.
Nam 1980, Eiden, Jewell va Wightman thong bao v~ kha nang hip thu Cr(lll)
va Pb(lI) nho chitin va chitosan. Nghien cuu nay con k.h~ng dinh Stl hip thu
kim loai tren chitosan xay ra t6t han, hi~u qua han so vdi chitin va eho r~ng ca
ehe- hip thu kim loai c6 lien quan de-n cilu tao hat nhan va Sll gia tang cae
da
Lu(in an TI'(lC sji - TfI((lng Nil Thanh Ttim
Chuang I. Polysaccharide mimg va lac d(jng eua cluing len tlwe \1(;21
di~n lich tren b'; m~t polymer (theo Eidcn, A., C. et ai, 1980) [25].
8
am 1982,
Maruca va Wightman nghien cuu sau hdn Sl.t hlnh thanh cac di~n tich va thie't
I~p co che' hap thu chromc (Cr) nho chilin va chitosan va Xilc nhan hap thu Cr
nho chitosan hi~u qua hon so vdi chilin. Kich thtldc cac phan doan (fragment)
dng nh6 thl s'f hap thu Cr cang t6l. Stl hap thu Cr cang tang khi pH dung dich
tang hoac c6 stl hien dien cua phosphatc (Maruca va Wightman, 1982) [51].
Nam 1992, Peniche-Covas va c(lng Sll c6ng b6 kha nang hap lhu ion Hg nho
chitosan. Nghien c(tu v6 dQng hQc hflp thu cho tha'y ty 11$ hflp thu ella Hg tren
chitosan c6 the dLI,!c 19 giili trong thai gian khuech lan cac hat ben lrong. Cae
du li~u thi nghi¢m v'; can b~ng hap lhu lU dung dich Chloride lhdy ngan c6
tllong quan chat che den phtlong trlnh dllong diing nhiet Langmuir (PenicheCovas, 1992) [61].
ling dung kha nang b~l kim loai clla chilosan, nhi';u nghien c(lu v'; xtl' 19
ntldc thai, bao ve m6i u,long nho chitosan da dtl'!c lien hanh. Vira qua, vao
thang 911998, lai h(li nghi Hin thu III khu vtlc cbilu A Thai blnh dtiong v';
chitin va chilosan l6 chuc lai Keelung, f)ai loan. Gorovoj (Ukraine) va
Kosyakov (Russia), vdi nh~n dtnb chitin c6 ch(lc nang hap lhu kim loai nang,
dac biet chilin c6 ngulln g6c tir nam c6 chUc nang bap thu kim loai cao bon so
vdi chitin c6 ngulln g6c tir t6m cua, da dung chitin tir nam "MYCOTON " lam
dau hieu sinh lhai va h(la h~n cho viec giai quye't hau qua lai n~n t~i nha may
nang ItI,!ng nguyen lil Chernobyl va (Ing dung M khtl' cac phe lhai kim loai
lrong c6ng nghi¢p kim IO<;1i n~ng, d~c bil$t chu trQng dtn cae nguyen to sieu
uranium (lransuraniulll) (U, Pu, Am, em) va cae dang vj Cs (Gorovoj va
Kosyakov, 1998) [311.
Chitosan c6 tlH~' dtl'!c ung dung M' tach kim loai nang ra kh6i ntldc thai
tir cac nha may dien than, thep, h6a chat, khoang hoac san Xual ntldc sach
phuc v~ sinh ho~t qua he th6ng Iqc chitin M Iqc mldc thai v.v. (Tatsumi
etal,1998; Kim, B., Y. etal, 1998) [77,451.
II. Oligosaccharide mang "a tl.lo'ng hie cua chung Jen thtfc vijt
Oligosaccharidc mang la cac polysaccharide mang mach ng~n chua
chirng 2-15 monosaccharide . .Nam 1985, Peter Albersheim va Alan G. Darvill,
th6ng bao v'; chat di';u hoa sinh tiliong thllc V~l mdi gqi la
"oligosaccharin", d6 chinh la oligosaccharide. Chung la nhung philn manh
(doan) (fragments) cda thanh le bao, dllOC liet ra tir thanh te bao do enzyme.
Cae loai enzyme khae nhau se tao ra cac oligosaccharide khac nhau. Moi
oligosaccbarin XUal hien se cung dp lh6ng tin di';u hoa m(lt chuc nang d~c
Lu(;n
all Thqc sji . Tn,((/Ilg Nil Thanh T(;m
Chuang I. Polysaccharide mimg va Ilk dQng ClIO cluing len [Iwc \1(;11
9
hi~u
nao d6 d thllC v~t. Cac chuc nang d6 la: phan ung tll v~, sinh tllrdng va
phan bi~ttrong qua trlnh phattrie'n, chgng han: luc nao thll~O ri!:, khi nao thl
hlnh thanh ch6i, la, hoa va qua [II].
Oligosaccharin dau tien duqc biel de'n c6 ngu611 goc let nam va hO~llfnh
sinh hQc cua chung (fa dl(qC kiGrJmlfin dau lren dic 1116 thl.(C v~l h~l kin
(angiosperm). Cac hoat t[nh sinh hoc '!iy c6 lien quan de'n hoal di)ng ctla cac
ph"n ung tll v~ (Albersheim va Valent, 1978). Sau d6, nglloi la m(ji phat hi~n
d thtlC vat bile cao cling c6 oligosaccharin va cling c6 the' gay ra phan ung III
v~ (Nothnagel et ai, 1983, York, Darvill va Albersheim 1984). C:Ie
oligosaccharin iii cac oligosaccharide dac bi~t. Chung khong chi la c:le
hydratcacbon c'!i.u tao hay ngu6n nang ILlCing ma chung cling c6 the' gay cac
"nh hlldng sinh hQc len mo IhLfc vat d n6ng do th'!ip (Albersheim ct ai, 1983).
VI v~y l'!it d cac oligosaccharin la dc oligosaccharide Llhltng khong ph"i t'!il
d cac oligosaccharide la oligosaccharin (theo Aldinglon va Fry, 1993) [12].
Oligosaccharide c6 tac dung doi vdi nhi6u ho~t di)ng thlfc v~t, nb'!it la
doi vdi phan ung III v~. Vao cuoi nhung nam 70-80, ngoai cac hCip ch'!ilt~o ra
bdi phan ung phyloalexin, la ch'!it khang sinh do thLfc val tao ra de' choLlg I~i
tac nhan gay benh (vi sinh val, n'!im), cac polysaccharide khac cling dllCic
cong nh~n la c6 kich lhich ph"n LYng tlf v~ d IhLlc v~t. Oljgosaccharide d6ng
vai Ira nhll mi)t lac nhan (elicilor) U'ong ph"n ung tll v~ d thllC v~t. Mi)t lrang
cac hoal di)ng ILf ve ctla thlfc valla lao ra su hoa g6 (16ng hCip lignin) ngay l~i
ve'lthll<1ng. C6 Ie tac dung dll<1c bie't rong rai nh'!il ctla oligochilin la gay ra
hien lllCing h6a g6. Phan (Ing xay ra d la cay lua ml khi liem vao n6 mQllac
nhan khong gay b~nh. Slf hoa g6 nhanh ch6ng da xay ra tai mep ctla ve'ltiem.
Ph"" ung tll v~ xay ra nh~m muc dich ngaLl khong cho lac nhan gay b~nh
li6m in c6 di6u ki~n phattrie'n (Ride, 1975; Bird va Ride, 1981; Beardmor
et ai, 1983; Morschbacher et ai, 1986; Ride va Barber, 1987) (theo AldinglOn
va Fry, 1993) [12]. Vdi pectic cling v~y, khi nuoi c'!iy huy6n pho te' bao thilu
dilu (castor bean), ngLloi ta da khgng dinh rhng cac c'!i.u u·uc oligouronide da
gay ra sinh t6ng hdp lignin (Bruce IU., Wesl C. A., 1989). Viec sinh t6ng hCiP
lignin da xay ra sau khi lhem cac phan dO':ln peclic van m6i In(ong llu6i cay
(theo Ryan and Farmer, 1991) [64].
Kich thudc (trQng ILlCing phan ttt) ctla cac oligosaccharide ho~t di)ng sinh
hoc da dll<1c nghien cuu ro rang trang phan ULlg ttl v~. Eloi vdi oligochitin, cac
oligochilin c6 hoat di)ng sinh hoc manh thuOLlg c6 kich thlldc phan til' ttl' 4 de'n
6 duong d<1n (moLlomer). Teu'asaccharide (phan doan chitin g6m 4 saccharide)
dll<1C phan giai nho enzyme chitinase theo ph"n (Ing:
Lu(in {in Th(lc 5Y - Tnl(/l1g Nil Thanh 1am
Chuang J. Polysaccharide mang va
laC
dQng cila chung len
IJIl!C WJI
10
Gic Ac - GIcNAc - Glc Ac - GIcNAc + H2 0 ---> GlcNAc - GIcNAc +
GIcNAc - GlcNAc
lao cac disaccharide (phan doan chilin gam 2 saccharide) se lam mill di hO~1
linh oligosaeeharin elia 116. Thf nghit$m eho lha'y die diu lnle phal1 lli' c6 kich
thlldc Idn hOn 4 saccharidc kh6ng c6 kha nang lin hi~u d6i vdi vi~c gay ra slf
gil h6a tren cay lila m] (Ride va Barber 1987, Barber el al,1989) (theo
Aldinglon va Fry, 1993) 112J.
oligopeelic, thi nghi~m tren dc te' bao thilu
dilu nu6i city buy~n phil, nglloi la cung thily kich thlldc cae doan pectic trung
binh lit 7-13 dOn vi c6 ehifa cac tae nhan (elicitor). Trong qua trinh nuoi cily
huy~n phil kh6ng b6 sung oligopeclic, 6 cnzyme oxy h6a ngoai bao (trong d6
2 enzyme la cac anion va 4 enzyme can lai la calion) khong hoat dqng. Nhllng
trong ph,!n ifng c6 b6 sung them cac phan doan peclic c6 trqng IWJng U·ung
blnh 7 don vi vao m6i InlOng, 4 enzymc (lrung d6 mql la anion va 3 la cation)
da hoal dqng va Xuill hi~n them ba enzyme mdi. Do d6 viec 16ng h'ip lignin
trong phan (Ing vdi oligouronide nhanh hOn so vdi Slt t6ng b'ip ho~t chilt do
phyloalexin bdi nilm trong cac he Ih6ng nghien cifu khac 1641.
a
Hoat dong gay ra 16ng h'ip enzyme khi c6 tae nhan xam nh~p cung la
hoat dqng tll v~. Oligochitin c6 kha nang gay ra phan ifng lie't enzyme
chitinase d Ma. day, nglloi ta lhily oligochilin ho~t dqng hieu qua nhilt gam
cac oligomer c6 kfch thlldc lit hexas (phan doan chitin c6 6 saccharide) de'n
nonas (9 saccharide). Oligosaccharin dll'ic tiem vao dlldi Idp bicay dlla va ke'l qua cho thily enzyme chitinase da dll'ic t~o ra lrung vong 6
gio. f)i~u 19 thll la IlYng kich lhlldc cua oligomer qui dinh cho litng loai hoat
dqng cua enzyme chilinase (la enzyme dll'ic sinh ra sau kbi liem oligomer).
Hexasaecharide va heplasaceharide l~O ra hO~l dQng ngo~i bao
(endo-activity) U·ong khi tit hepta de'n nonasaccbaride I~i tao ra ho~t dqng nqi
bao (exo-activily) (Roby el ai, 1987). Oligochilosan cung gay ra viee lao
enzyme chilinase va f3 glncanase trung nuoi cily te' bao cay dau cung tliOng tll
nbll qua lrinh 1~0 enzyme khi cay d~u bj nhi€m d hai lo~i nilm lllOng b'ip va
bilttllong h'ip (Mauch va cqng Sll, 1998) (lheo Aldinglon va Fry, 1993) 112J.
oligopeclin, vic$e lie't ra enzyme lhdy phan pectin khi Hie nhan vi sinh V~l
Envinia carotovora xam nhi€m len cay Ihu6c la, ke'l qua cho thily gay ra hqal
dqng cua cac enzyme chilinase va f3 glucanase (Broekert W. F.,Peuman W. J.
1988). Ho~tt[nh eua enzyme ehitinase lang 12 liln trung vong 48 gio. TY Ie
elle dai ella viee gay ra hoat dqng enzyme d6 xay ra lrong vong khoang 12-24
gio, khoang thai gian d6 tllOng tll vdi thai gian gay ra hoat dqng ife che' sinh
t6ng hOp proteinase nho cae phan doan pectic (Walker - Simmons M.,
Hadwiger L., Ryan CA., 1983). M(le dq gia tang enzyme chitinase va f3
a
a
Lwin an Th(IC
s9 - Tn..((lng Nil Thanh 'lam
Chuang I. Polysaccharide mimg
va uk dQng eua cluing ten thf(C v(it
II
glucanase co tlnh chill cuc bq va rilt co h~ th6ng Irong lrong viec phan ung lai
tiic nhan gay b~nh. Vi~c tie't ra cae enzyme thuy pban pectin va cac pban
doan pectic tif thanh Ie' bao da duqc nghien cuu Iren cac tac nhan gay b~nh la
nam, vi sinh v~t va Sl! tan cong cua con lrung. Tac nhan gay b~nh Fusarium
oxysporumj sp. Radicis-lycopersici d,rdc thl nghi~m Iren r~ cay ca chua. Su
dla phudng hoa cac thanh ph~n pectic thanh Ie' bao dudc nghien c(ru co sil
dl.' ng leclin g~n vdi polygalaclUronate tiich lif Aplysia delipans. Kinb hien vi
di~n Ill' da phal hi~n ra Sl.r giai phong cac phan do~n oligouronide t~i vi Iri tiic
nhan xam nh~p. Trong rna re ea chua dtfQc gay nhiem bhng Fusarium
oxysfJorum f sp. Radicis - lycopersici, s~t bien d6i lhanh te' baD CIa xiiy ra t~i
cac kenh phuc vu cho qua lrlnh Ihilm cua Ie' bao nam. Trong qua u'lnh gilli
ph6ng cac phan dO<;tn peclic, mQt s6 phan dO<;tn da xam nh~p vao dic le' b~1O
libe bi bie'n d6i ily. Cau u'uc nang n6 cua cac phan doan oligopectic Irong
khong gian nqi bao va vi~c g~n mang Ie' bao t~i ndi tie'p xuc gilra Ie' bao tbltC
vat va ti!" bao nilm cho thily vai IrO cua chung nhu mqllin hi~u hoat hoa h~
thong phan ung tu v~ d ti!" bao thuc v~1 [641.
Cac oligochitosan co the gay ra d6ng thoi hai phan ung tlr v~ mqt la bao
Iren IhlrC v~t va hai la uc chi!" sinh Inrdng cua nilm tiln cong (Hadwiger va
Beckman, 1980; Hadwiger va Loschke, 1981; Walker Simmon et ai, 1983;
Kendra va Hadwiger, 1984). Thi nghiem cho thily oligochilosan c6 lac dung
chong nam Fusarium solani lren diy d~u Pisum sativum va gay ra t6ng hQp
phyloalexin pisalin. Oligochilosan c6 klch lhlrdc 7 ddn vi c6 lac dung nhill
(Kendra, F. D. and Hadwiger, A. L., 1984) 143J. Oligoehilosan cang gay ra
16ng hdp callose lrong It bao Ihlte vat bac cao (Kauss et ai, 1989). Kendra va
Hadwiger, 1984, khang djnh oligoehilosan e6 trQng htqng phan l,r nhi) nhilt c6
hoat dqng nhu la mqt elicitor (laC nhan) lrong su blnh lhiinh phyloalex;n
v~
pisatin
va
e6 the ue che' sinh u·ltong nam
HI
u·isaccharide
m~c du
heptasacebaride e6 hO~1 dqng Ill~nh nhilt 1121.
Theo Walker-Simmon va eqng su, 1983, oligochitosan khong chi la tac
nhan gay ra sinh t6ng hqp pisalin rna chung con la chill lao ra chat uc che'
tang hqp proteinase lfen 1;1 mam ca chua. Tlr' 1972, Ryan va cQng Sl.t da quan
Sal thily hien tlrqng lich lay mqt Ilrdng Idn cac cbill (rc che (inbibitor)
proleinase sau khi c6 su liln cong cua con u·ung. Sau d6, Ihl nghi~1ll da cbung
minh vic$c t<;to ra cae inhibitor 13 c6 hc$ th5ng va chung dl(QC ch((a l~p trung
Irong la nhhm bao v~ chong lai proleinase serine (Ia Illql loai enzyme c6 lac
dl.lng lieu htly) ctla con lrung (Ryan, C. A., 1992). Hdn nila vi~c lao ra cac
chill uc che proleinase c6 llnh dia pll[(dng da dlrqc quan Sal khi xii 19 chiLOsan
hoac oligogalaclUronic.
LU(in an Th(IC sji - Trllung Ni111ullllt T(lm
Chuang I. Polysaccharide 11!C111g
va tde di}ng ella cluing ten "lI/c ,,{it
12
Thi nghiem cho thily oligochitosan ng~n nhilt c6 hoal tinh kich thich gen
ho~t d(jng sinh ra chit uc che proteinase khi c6 vet thtidng la pentasaccharide
(Ryan, 1988; Aldington, 5.,1991) 165, 13J. Ngoai phytoalexin pisatin du'dC tao
ra, DlQI phytoalexin kMc ciing du'<;lc t~o ra do ho~t dQng cua oligochitosan Iii
glyceolin khi nuoi cily huyen pho Ie' baa d~u tu'dng. Trong qua tr1nh nuoi cify
nay, nglloi ta ciing thily mQt lac dung khac nua Ia oligochilosan lam gianJ ty
19 sinh tru'ang to' baa, liing cac h<;lp chilt ki€'u phenol lien ke't vdi thanh Ie' baa
va tiing callose. Tac dung nay lam lhanh Ie' baa v~t chu u·a nen ben hdn, tiing
S(ic d~ khang hdn lrt,dc sV phan huy cua phuc h
Oligochitosan con c6 lac dung gay va mang te' baa d6 kich thich lang
h<;lp callose lrong nuoi cify huyen pho Ie' baa d~u tu'dng. Callose Iii DlQt
polysaccharide c6 ch(la ty 19 !dn cac 13 (1-3) D glucose. N6 tham gia vao cac
phan (Ing dap lai cac tae dQng (su·ess) V~l 19 hay h6a hoc. T6c dQ sinh lang
h<;lp callose va vi lri lham gia phan (Ing clla callose c6 th€' xac dinh r6 VI d6 Iii
mQt phan (Ing Itt V9 quan lrong. Khi nuoi cily huyen pho Ie' baa d~u tu'dng c6
xtl' 19 oligochilosan, sinh lang h<;lp callose b~t dilu 20 phUl sau d6. Miic do
Ca'· hi phong be' (blocked) lrong phan (Ing (Young et ai, 1982) nhu'ng sinh
tang h<;lp callose v5n phu thuQc vao kha niing dieu lie'l Ca'· lrong te' baa
(Kauss el ai, 1983) va dieu nay chI thily du'<;lc khi Dlang Ie' baa bi va du M tao
ra mQI dung dich di9n phan (Kahle cl ai, 1985) (thea Aldington va Fry, 1993)
112]. Oligochitosan con gay ra phosphoryl h6a nhanh ch6ng va nhill thai
prolein diic biel lrong nuai cily huyen pho Ie' bao ngo lay I'elroselinum
crispum . Stt phosphoryl h6a xay ra rill sdm sau khi xir 19 chilosan (I phut).
Phan ung nhanh ch6ng dap lai tac nhan nay phu IhuQc n6ng dQ canxi lrong
moi lrllong (Diclrich A., el ai, 1990) 1241. Oligochitosan, diic biet la cac phan
doan c6 lrong Iu'<;lng phan ttl' cao gay ra sll giai ph6ng canxi nhanh ch6ng trong
Ie' baa Glycine max d5n de'n tu'dng lac v6 n6ng dQ canxi giua thanh te' baa va
mang plasma (Young H. D. va Kauss H., 1983) 195J.
Miic do cae anh hu'ang lien quan de'n mang Ie' bao da r6 rang lrong nuai
cily huytSn phO nhllng Kendra va Hadwiger (1987a) thily rhng lrong ma mtSm
v6 cay d*u dlldc liem Fusarium solani, st.l h1nh thanh dung dich dien phan
(Illdng III nhll thi nghi9m cua Kohle va cQng su' 1985) do oligochilosan gay ra
Xuill hi9n sau 24 gio khi st.l r6 rl cae ion mang di9n gia lang (c6 lh€' Iii do nilm
phallri€'n nhanh hdn so vdi cac hi9U (Ing di)c biet cua chilosan). Viec gay ra
phan ung Ill' V9 nho chilosan xay ra lrong 6 gio va phan (Ing m5n cam bill dilu
vai gio sau d6. C6 thtl tac dung clla chitosan l~i vi lri ve't thu'dng gay ra do st.l
Lu{in an Th(lc sji - Tnl
Cilltang I. Polysaccharide mimg va lac dong cua chling ten thlfc ,,(it
13
xam nh~p cua niim c6 Hie dung sdm hOn nhi6u nhung tai thai di6m d6 ty I~
chua du M gay nen slf ro r1 di~n h6a du M c6 th6 nh~n biet dlrqc. NguOc lai
lrong nuoi cily huy6n phli, till d eac le bao Mu bQc IQ hieu (rng u·ong cling
I11Ql li611 oligosaccharide llhl( nhall do d6 cac phan ((llg dl(qC l~p trllllg l'.1i nen
d6 nhGn biet hOn [121. Thi nghi~m lrcn cho thily linh 1m viel clla h~ th6ng
nu6i diy in vitro, rnang l'.1i sl! d6ng bQ v6 sinh 19 hO'.1t h6a le' bao, tranh dl(qe
nhi~u 10'.1n do vi sinh v~l, lam lang de) ehinh xac eua ke't qua.
Su hlnh tbanh va v~n chuy6n cac lin hi~u te bao xay ra mQt each h~
lh6ng va c6 linh cuc bo. Khi c6 Slr xam nhap cua tac nhan hoac con trling tiln
cong, OlQt prolein dtrqc lao ra mot each c6 h~ th6ng g6m 200 amino acid Iii
prosyslemin dl(qC chllyc$n d6i thanh systemin. Syslemin dl(qC ehuyc$n vuo
mach libe (phloem) va SIr nhan biet n6 dUn Mn viec lam tang n6ng dQ acid
linoleic len. B~ng eac cong CI.' Iii eac enzymes 13-lipoxygenasc dinh vi u·ong
diep luc (chloroplast), allene oxide synthase vii allene oxide cyclase, thl 12oxo-phytodienoic acid hlnh thanh vii cu6i cling duqc U·ao d5i vii budc ~
oxyh6a peroxisom chuy6n 12-oxo-phytodienoic acid thanb (-)-jasmonic acid.
EJi6u nay t~o nen amino acid tiep hqp ma chung ding ho~t dQng nhlr cac cbilt
dm (rng (inducers) ctla gen phan ling khi c6 vet thuOng (theo Waslernack, C.
and Parthier B., 1997) (hlnh 2) [90J.
Ethylene cung Iii mQt lin hieu h~ th6ng hoat h6a gen hoal dQng khi c6
vel uurong cling vdi jasmonic acid lrong la ca chua. Acid abscisic va cac lin
hieu c6 ban chilt dien cung la eac phan lit di6u bOa mang dien duong hoat
dQng theo con duong oCladecanoic (Herde,G. el ai, 1996, Pena-Cortes, H. et
ai, 1996) (theo Wasternack, C. and Parthier B., 1997) [901.
Vi~c
th6ng va
kich dQng enzyme hoat h6a protein trong phan (rng lit ve c6 tinb
dia
phlrOng da
Moc quan Sal khi
Xlt
b~
19 chilosan hoac
oligogalaclUronic. ThGt vay, khi gay vet tht(Ong lren la ca chua da gay kich
dQng enzyme hoat h6a protein cO ban myelin (myelin basic prolein-MBP) va
hoat dQng ella enzyme hoat h6a nay ciing lang u·ong phan ling dap
systemin va oligosacchride (dac
(Stratmann, J. el ai, 1997) [74J.
LUQn
an rh(lc sy - rrt(cmg Nt7 Thanh Tam
bi~t
I~i
oligochitosan va oligalaclUronic).
Chuang I. Polysaccharide ",cing va Idc dQnJ.: dia cluing ten Owe v4t
14
HertllvcNe wounding
I
ProsyslemUI
procesSIng
I
Systemin
transloc
I
I
•
I
loce. ,ignals
I"",~
" , . Systemic
•
sIgnal
,
•
•
••
•
TT
T
I
-t1~
1 0
1/
Ultraviolet
T
I
~
-------
~
AbscislC acid
'i. ~
<~
... ,
,
~oo-
'--0
I
galacturooides CtMlosan Burning
I 13-~poxygenase
I Alieno OXJfJo synthol50
I A~O oxldo cydastl
,,
,
COO~
12-o_o-POA
I
1
~
JA-L-amlllo ilCld
COIl/Ugales
-
V
Jasmonic acid
'-Gene
-Ethylene
'~tJYaijon
Hinh 02. Con (luang tin hi~ll ocradenlfloitl df;'i viJi JIO{ll h6a h~ thong gen t~( vr
/995). System;n tin hiru tluqc hinh thanh mQt each
e6 h~ Ih6'ng lit prosyslemin I{,i noi ('6 \·P·t thitan!.: Vii tit acid ahsdsic (la mQt
acid nQi sinh phl;' thuQc S~( /(111g 116ng d(i arid linolenic). Dua; xlic tac cua 3
el1zyme iti /3-lipoxygemue. al/ene oxide synthase wi al/ene oxide cyclase, acid
linolenic hie'n Ih(inh acid 12-oxophylodienoic. Acid jasmonic duqc t{lO ra do 51!
khi't WI 3 bt(Oe oxy hoa 12-nxophylodienoic. HO{ll !u)a gen dia pJIt/ong xdy ra
thea COil duang neiy bc71 (Mil va; acid linolenic. Elhylenc (An thie'l cho hO{ll dQng
lru)'~n tin hifujas/Ilof!ate. Cdc dci'll cring (+) chf djnh kich thfch. Cdc miti ten
clIft giiy chi cl,inh c(m (li(ang gid djnh_
a CQ chua (Schaller \lei Ryan.
Ngoai viec Iii lin hieu gay phan ling III
v~
11
~llfc
val, oligosaccharide
con c6 anh hllong len ,inh tnlc1ng va phat tridn 11 lhllC V~1. Nghien cU'u dftu
Lu(m
S)~ - Tn(lmg
NCr Thanh Tam
Chuang I. Polysaccharide mcmg va lac dQng eila chu_ng len lh{IC v(il
15
Lien ve Lac dung cua oligosaccharidc, L~O ra do Lhuy phan Lung philn
hydraLcacbon Lhanh Le' baa, nhula chilL dieu hoa sinh WOng va pha[ Lri€n thlic
VaL duoc thuc hien Lren beo l1lm Lemna gibba. Cac phan doan da c6 anb
huang len su ra hoa va sinh Lrl1ang thuc VaL (Gollin D. J e[ ai, 1984). Cae pban
do~n cua tha-nh
te' baa thl.fc v~t gay nen 51! thay d6i cac d~c diem hlnh thai khi
nu6i c1iy lap mong Le' baa Lhuac la. Ph~ LhuQc vao Lhanh philn m6i Lnlong cac
phan do'.!n nay la ngllyen nhan gay ra Vi9C mall dly l'.10 ch6i lhay VI phai l'.10
hoa hay call1ls va mall cay hlnh lha-nh hoa thay VI hlnh thanh ch6i (Kiem Tran
Thanh Van eL ai, 1986) 144J. M9i n6 Iltc [ai Lao lai k6[ qua nay deu kh6ng
hoan Loan thanh c6ng nhllng cac lap mong te' baa Lhuac la da dll<;lc dung de
pha[ [ri€n nghien C(lu ve ilnh huang cua oligopec[ic len Sl.1 hlnh Lhanh r~ va
hoa (Eberhard e[ ai, 1989; Mobnen e[ ai, 1990). Cac phan doan pecLic da uc
che' hlnh thanh r~ nhung lai lang cuong m9c r~ thea ki€u c6 djnh huang ve
cac cuc hoac kich dlich m6 pha[ Lri€n dleo huang Lao hoa, phu thuQc vao
[y Ie
giua nilng dQ auxin va cy[okinin Lrong m6i [nlong. Cac [ae dung c6 th€ du<;lc
Lh€ hien lai khi nu6i c1iy huyen phu [6 baa cay Lieu huyen (sycamore) hay Ie'
baa thuac la c6 bil sung cac phan doan pecLic. Cac lac d~ng cua cae pban
doan ily kh6ng [h€ giai Lhich dUoc b~ng co che' Lang hay giam 1[I<;lng auxin hay
cy[okynin trang m6i ~1iong, vl sll thay dili cae nilng dQ ily (auxin va cyLokinin)
trang m6i Lnlong nu6i cily kh6ng mang I~i k6[ qua Lllong Lu nhll cac phan doan
pecLic da mang lai (thea Ryan and Farmer. 1991) [641.
Thea [hi nghiem lap Ie' baa mong (V. Marfa va P. Albcrsheim),
oligouranide hien dien Lrang qua [rlnh LhLly phan Lung philn thanh [6 baa thuc
v~t da gay ra 51! hl11h lhanh hoa lren mall cay thuoc la. Oligollronide nay c6
kich thuac phan LU Ian hon 6 don vi. Khi thi nghiem mQ[ 10aL cac
oligogalaclUronide [inh che' Lheo phuong phap thuy phan pec[in h9 cam chanh
Lrong acide nhe, uronide c6 kich thllac phan LU duai 10 thl bilt hoa[ trang thi
nghiem, [rang khi oligomer c6 kich thuac phan [U 10 va I I thl hoaL dQng va
oligomer c6 kieh Lhllae phan Lll Lil 12-14 hoal dQng manh nhilt. Cae kich thuac
eLla eac oligomer hoaL dQng kich [hich sinh LnlOng ril[ giang vai kich thuac cac
oligouranide gay ra philn (Ing Llt ve chang lai Lac nhan gay benh.
OJigouranide lam tang cuong phosphoryl h6a proLein mang L6 baa chill e6
kich Lhllac [u 14-15monomer khi nu6i c1iy L6 baa Ia oil chua va la khoai Lay
Lrang philn (Ing van chuyGn tin hieu (Farmer E. E. etal. 1991) [271. Kich thuac
eLla Oligogalacluranide gay huy d(lng canxi Le' baa chill. lam milt Linh phan
uI(in an Th(IC sji - Truong Nil Thanh T(lm
Chlf{jllg I. Polysaccharide mllllK vci Ide dtjllg Clla dUIIIK
Ie"
Owe ,'(it
16
Cl!C Clla mang va lam acid h6a IC' biw Chal khi nuoi dly Ie baD C3rO'1 Daucus
carota la 9-16 monomer (Messianen J. va CUlsem, V. P., 1994) 1561.
Oligopeclic c6 kha nang uc chi{ hO~1 dong ella auxin lrong Ie bao. Nam
1996, Bellincampi nghien cau vai tro n1a oligogalacturonide trong hO;;ll dqng
((c ehe' Auxin cho th5'y oligogalal:turonidc c6 vai Iro doi I~p veti auxin. Chung
(i'c ehe' h1nh thanh n:; do Auxin khi IllHli dfy tc' hao lhunc la c6 chuyin gen raJ
B cua Rhizogenesis. NhL(ng ngL(Qc l<;Ii, khi vi~c chuy<3n gcn tJlLrC hi¢n d(jc I~p
vd'i auxin, mau cay thu6c la c6 mang gcn roJIJ cua Rhizogenesis dL(Qe ehuyen
b~ng chill khdi di)ng la lClraciliin. vJin ph,ll Irii!n rc hinh !huong (Bellincampi,
D., 1996) {171.
Ta bie't hai cd chc sinh ra auxin frong vi¢c keu dili
te bao tillre v~tl1l(jl
Hi
do kel qua clla slt ti;;! ion H+ (.lacoh cl ai, 1975, Thcologis A., 1986), c6 Ie e6
lien quan dc'n hoat di)ng ella enzyme hydrolase luon c6 mal lrang !hanh le
hao (Me Dougall el ai, 1990; Farkas. V. and Maclachlan, G., 1988) va hai la
do hoat di)ng sinh t6ng hdp cellulase da milt trang eftu trUC !hanh teO bao
(Verma, D.P.S. et ai, 1975). Cae Ihanh philn eftu Irue ella oligosaccharide
xyloglucan ella thanh te bao so cap ClI thi! anh hudng len hoal di)ng kith !hith
sinh tnrdng clla auxin d milm dau (York, W. S. et ai, 1984). Mi)t
nonasaecharide eua xylogluean (ky hi~lI 1ft XG9) cO cifll true nhLJ' sau:
FUC
all.. 2
GAL
XYL
xn
all-..6
all-..6
81 1-..2
xn
all-..6
GLC 8-1-.4 GLC 8-1-+4 GlC 8-1-+4 GLC*
lfillh 03. eftu Infe nill xylaglucCln ( XG9 )
FUC: I.-Fucose; (;,\L f). (;"Iactose; G/_C: f)-glucose;
XYL: D-Xylo.'ie; crm 1(li: Pyranose.
Lu4n an
Th(IC S)' .
Tn((mg NI1 71umh Ttim
Chuang I. Polysaccharide mlmg va lac dQng clla cluing ten IhIlc V41
17
XG9 dii uc che' sl! keo dai m~m dilu do auxin trong khi cac philn doan
nho hdn cua xyloglucan (XG7 va XG8) va dic phiin do~n Idn hdn (XGIO)
hoan toan khong hoat di?ng. XG7 thie'u nh6m Fuc-Gal-, XG8 thie'u nb6m Fuc-,
XGIO thi lai c6 them mi?t nh6m galactose d cu6i mach. Hai oligouronide nh6
hdn Fuc-Gal-Glc va Fuc-Gal-Xyl-GIc-Glc, vdi trisaccharide c6 hoat tlnh g~n
nhu hoat Hnb cua XG9,
hai deu c6 ho~t Hnh uc che' auxin. Eli6u nay cho
thffy c6 the' c6 Str hi~n di~n cua mi?t chfft nh~n c6 kha nang philn biet cao
nh~n bie'tdlrdc vi U'I fucose trong phan ttL N6ng di? cao cua XG9 (10·'-IO·6 M)
ca
IllIll ghlm bdl hOi;ll linh ((c che' auxin clia phan lit nhl(ng ndng dQ cao hon clia
pentasaccharide lai khong lam giam hoat tlnh erc che'.
Cd che' dieu hoa xyloglucan cua hoat di?ng auxin c6 the' licn quan de'n su
dieu hoa hoat di?ng cellulase U'ong qua trjnh sinh u·udng. Mdi dily, cac nha
nghien cuu cong b6 ccllulase ngli c6c (Mc Dougall et ai, 1990) va cellulase
d~u tudng (Farkas, V. and Maclachlan, G., 1988) trong dieu ki~n in vitro, hoat
tlnh cua chung tang len gffp 10 I~n nhiJ bG sung XG9 vao moi tnriJng vdi n6ng
di? 1-200 nM. Hoat di?ng cua enzyme chi quan sat dUdC khi polysaccharide
xyloglucan lam nen cho enzyme. Enzyme se khong hoat di?ng khi khong c6
chfft nen nay. Hoat di?ng cua XG9 c6 the' c6 dllqc la do kha nang hoat h6a
cellulase cua n6, nhiJ d6 chung d€ dang anh hlrdng len su sinh tnrdng cua te'
bao, cu the' la lYe che' qua U'inh keo dai te' bac;>. C{j<;Q1i?pm.e( . log,I\J~a:n khac
cling la chfft hoat h6a cellulase. Cac san phi,J ki,ac ctlit qu~ tfinh 'phan giai
!
dh m,~ch cung c6 lha' lham gia vao hi~u ((ng 1~~Yi~i";\';_.
l.· ..
:J{:J
I
.•
Q3..C~~ ~
XG7 va XG9 xen ke nhau dqc theo chieu dai clla polysaccharide
xyloglucan va d hai oligosaccharide c6 the' dlrqc giai ph6ng trong qua u'inh
thl'y philn nhiJ enzyme cellulase. Vi v~y cd che' lien h~ nglrqc (feedback) c6
the' lien quan tdi XG9 (XG9 cling duqc giai ph6ng nhiJ cellulase) nhula mi?t
chfft boat h6a hoat di?ng cellulase, dac biet d6i vdi viec dt m~cb chu6i
xyloglucan.
Khi XG9 danh dffu ph6ng xa (thlriJng la dilng 14C) dudc bG sung vao moi
tnrang nuoi cffy huyen phil te' bao d n6ng di? 10 nM, mi?t s6 XG9 da xilm nhiip
vao te' bao va dllqc philn giai. Ba ph~n tu XG9 drrqc g~n vdi polymer ngoai
bao. C6 the' xyloglucan, dtrdi dang transglycosylalion, chi thi muc dO XG9 in
vivo, dii dlrqc dieu chinh theo cd che' nay, vi v~y giup dieu hoa qua U'inh sinh
Iy keodai te'bao [611.
Oligopectic con c6 anh hlliJng Mn sinh tGng hqp ethylene va lam chin
qua. Ethylene thuang dlrqc sinh ra u'ong hoat di?ng dieu hoa lam chin qua cil
Lu(in an Th(lc sji - Trll{fflg Nil Thanh Tam
Chuang I. Polysaccharide mimg va tac dtJng cila chung len
th~(c
v(it
18
chua. OligopecLic kkh lhkh giai ma gen d;)c hi~u d giai dO<;ln sao ma va giai
dO<;ln sal! sao mao Mdi day, oligomer cua ca hai polygalacturonic va pectic
dlr'ic xem la c6 anh hlr6ng len sinh L
1988; BrechL, J. K. Huber, D. .I., 1988) va nuoi city huy6n phu Le' bao
(Tong, C. B., Labavitch,.I. M., Yang, S. F.,1986).
Cae isoenzyme polyglacturonase Uich tit thanh qua ca chua chin cua
polyglacLuronic I va polyglacturonic " khi tham nhaP vao qua ca chua giln
chin, stt sinh t
va polyglacturonic II) d6u c6 hi~u qua lich ct.rc d6i vt'Ji sinh t6ng hdp eLhylene.
Polyglacluronic 1 hi~u qua hdn polyglacturonic II (Baldwin, E. A., Pressey, R.,
1988). Khi Lham nhap vao qua chlra chin, cac phan doan pectin dlr'ic tach tii'
qua ca chua chin Lhuc My t6ng h'ip ethylene va lam chin qua. Ph6i hdp cac
phan do~n pectin vt'Ji cac polymer c6 kich Lhttt'Jc phan LU dttt'Ji 8 ddn vi th.
khong thily hoat dQng. Nhlrng cac phan doan tren 8 Lhl gay ra SL! t
polyglaclUronic tach tii' ca chua chtta chin khong nhung khong gay 16ng h'ip
eLhylene va khong lam chin qua, ma con c6 thcS lam giam nhanh ch6ng kleh
Lhlrt'JC cac oligomer dang hoat dQng xU6ng dttt'Ji ngl((Jng klch Lhlrt'JC hoat dong
(theo Ryan and Farmer,1991) [641.
Oligosaccharide con c6 Lac dung thuc My qua trlnh nay milm d hat, pMt
Irie'n chili d mQt 56 loai cay. Nam 1992, Yoshimasa Yonemoto va cQng stt tai
E)ai hoc KYOLO, hat ban cong b6 viec dt mach alginalnau·i (c6 U·ong Ittdng
phan tu u·ung blnh la 25.700) tii' mQt loai tao bie'n an dlr'ic Eisenia bicyclis nha
enzyme alginat lyase cua vi khu5n da t<;1o ra oligosaccharide c6 lrQng luqng
phan ttr u·ung b'nh 1800 cung vt'Ji cac Lhanh philn khac. Stt sinh trlr6ng va bi~t
h6a cua cay trilng dttdC gia tang Mn khi c6 mat oligosaccharide. Ke't qua
khilng djnh san philm oligoalginat da dtr'ic dt mach c6 chua cac thanh philn
oligosaccharide thleh h'ip c6 anh httdng len sinh tnrdng va phan h6a d Lht.rc
vat bac cao (Yonemoto, Y. et ai, 1992) [94J. Nam 1994, Yoshihisa Tomoda va
cong Sl.r Lhong bao alginat lyase-lysate du'!c dt mach bhng enzyme alginat
lyase c6 tac dung Lhuc dily tang ulrdng trong viec keo dai ...3 d cay lua mach
dac biet d6i vili cac r6 con. Xu Iy alginat lyase-lysate lam Lang khoang hai liln
hoat Hnh cua enzyme alcohol dehydrogenase cua moi trttang d6i chung trong
di6u ki~n hypoxic (Tomoda, Y. et ai, 1994) [79J. am 1994, Midori Natsume
va cQng Str cong b6 viec Lhlly phan alginaL bhng enzyme alginat lyase lily tii'
Alteromonas macleodii. B6n oligosaccharide dltQC tach tit algin at lyase-lysate
Lu(in tin
TI/(IC
sy - TrtMng
Nil Thanh Tiim
Chuang I. Polysaccharide mimg va uk dong elta cluIng len Owe Vt;ll
19
bang phliOng phap s~c kji lIao dili ion la nhllng Ihanh philn chlnh glup thuc
My tang Iniong r~. Ke't qua cflng cho thily Irlsaccharlde tach tll cac san pha'm
Ihuy phan e6 hoal tinh thuc My sinh InrOng r~ 0 Illa mach (Nalsume, M. et ai,
1994) 1601
Ngoai ra oligosaccharide (dae hiet la oligoehilin va oligoehilosan) con c6
kha nang hiip thu kim loai nang tao ti6m nang ltng dung lrang cong tac x.r lji
phe· thai kim loai nang va lam saeh moi Irliang (Ulanski, P. va Rosiak, .I.
1992) [821. Nam 1998, Le Xuan Tham (Yi~n Nghien e(iu h~t nhan Dalal,
Yi~1 nam) ct)ng Matshuhashi va e(lng sli (Yi~n Nghien eltu Nang IIi,!ng
nguyen l.r Nhal han) da khhg dinh dQc linh vanadium Iren hat diiu tlidng, lua
nudc, lua mi, lua mach. Cac lac gia con cho r1lng su hu hai eua hat hla do
vanadium se giam khi dung chilosan dli'!c dt m~ch bang phudng phap ehie'u
xa. Yi~c giam Y va Fe trang tllliC viii c6 lien quan den kha nang I~O phuc kim
loai nang cua chilosan lrang dung dich. Nghien cuu con cho thily lac dung
kfch thich sinh tniong thl.!C vat xay ra khi dung chitosan du'!e chie'u x~ 0 li6u
100 kGy. Do d6 chilosan dudC ehie'u xa 0 1i6u chie'u thlch hap du'!c xem nhu
m(ll chiil kich thich lang truong !htie viii va loai ho kim loai nang lIong san
xuilt nong nghlep (Le Xu an Tham, Malsuhashi, el ai, 1998, 1999) [48,491.
B1Ing phuong phap dung d5ng vi danh ailu 18 F - H,O, "y va "N, cac tac gla dli
chung minh hit%u qua eua ehitosan chieu x~ chong xam nhiem vanadium tren
cay ILIa (H1nh 4).
T6m lai, oligosaccharide la polysaccharide chua 2-15 monosacchride.
Chung 15n lai lrang Ihanh Ie' bao niim, thttc viii va cac loai glap xac. Chung
d6ng val Iro quan lrang lIong h~ Ih6ng truy6n lin hleu di6u hoa c:l hai qua
IIlnh Itt v~ va sinh tniong phat Irie'n 0 tlll)'c vat. Oligosaccharide du c6 nguiln
g6c khac nhau nhting lill d d6u e6 the' gay ra phan ung tt)' v~ 0 thliC viit.
Chung d6ng val Iro nhli la mOl lin hieu tham gla vao h~ th6ng lIi ve ch6ng I~I
tac nhan gay b~nh. IhltC vat, Irong glai doan dilu khi lac nhan gay b~nh b~t
dilu xam nhiip, de lac nhan gay benh tie'l ra enzyme phan huy peclin de'phan
giai polymer (depolymer h6a) !hanh Ie' bao thuc viit va hoa Ian oligouranlde
ma dc oligouranide nay c6 Ihe' hoal dQng nhu cae lin hieu kheli dilu cho phan
ung Ili v~. Cae oligomer nay la m(ll trang de lin hieu dilu lien nhiit hoat h6a
dc phan ung Itt ve 0 Ihlie vat. Trang 56 de phon ltng d,«le tao ra trang thuc
v~t do oligoufonic thl phan (i'ng sinh Icing h0r enzyme p glucanase va enzyme
ehillnasc la de phon ung co tile" ph:,n hlly thanh Ie' bao niim. Cae oligomer
nay cflng co Ihe hoal dQng nhli de phan III di6u bOa dtt tnr, theo cach do mel
rQng de lin hieu eho cae phan ung lIi vc cue bli [MI.
a
Lu(in rin
Th~IC
sji - rrLlang Nil Thanh Tc1m
