Teko ea Ames bakeng sa N-Nitrosamines: Ho Lekola Mutagenicity

Selelekela sa Teko ea Ames

Teko ea Ames, eo hape e tsejoang ka hore ke Bacterial Reverse Mutation Test, e sebelisoa haholo bakeng sa tlhahlobo ea bioloji e lekolang matla a phetoho ea lik'hemik'hale, ho kenyeletsoa N-Nitrosamines. E thehiloe ke Dr. Bruce Ames lilemong tsa bo-1970, tlhahlobo ena e sebelisa mefuta e itseng ea baktheria Salmonella typhimurium e tsamaisang liphetoho liphatseng tsa lefutso tse amehang ho synthesis ea histidine. Teko e etsa qeto ea hore na ntho e ka baka liphetoho ho DNA ea baktheria, e fana ka sesupo sa kotsi e ka bang teng ea kankere bathong.

Bohlokoa ba Teko ea Ames bakeng sa N-Nitrosamines

N-Nitrosamines li tsejoa ka thepa ea tsona ea genotoxic le carcinogenic, kaha li ka baka tšenyo ea DNA ka alkylation le khatello ea oxidative. Teko ea Ames e thusa haholo ho lemoha liphello tsa bona tsa phetoho, kaha N-Nitrosamines tse ngata li hloka ts'ebetso ea metabolic ka phetoho ea enzymatic ho theha li-intermediate tsa electrophilic tse sebetsang haholo tse khonang ho sebelisana le DNA. Ts'ebetso ena hangata e hlaha sebeteng ka li-enzyme tsa cytochrome P450. Ho pheta phetoho ena ea metabolic in vitro, tlhahlobo hangata e etsoa ka ts'ebetso ea metabolic ntle le ntle le ts'ebeliso ea S9, e leng tokiso ea enzyme ea sebete e tsoang ho litoeba, e etsisang metabolism ea mammalian le ho ntlafatsa ts'ebetso ea mutagenic.

Mokhoa oa Teko ea Ames

Mokhoa o tloaelehileng oa tlhahlobo ea Ames o kenyelletsa mehato e latelang:

1. 1. Tokisetso ea Mathata a Teko: Mefuta ea Salmonella typhimurium e nang le liphetoho tse teng pele ho liphatsa tsa lefutso tsa histidine synthesis li sebelisoa. Mefuta ena e ke ke ea hōla ntle le mohloli o ka ntle oa histidine ntle le haeba phetoho e fapaneng e tsosolosa mosebetsi.
2. 2. Ho pepesehela N - Nitrosamines: Tloaelo ea baktheria e kopantsoe le motsoako oa teko (N - Nitrosamine) holim'a poleiti e nyenyane ea agar e nang le palo e nyenyane ea histidine.
3. 3. Ts'ebetso ea Metabolic (S9 Mix Addition): Ho ikarabella bakeng sa phetoho ea metabolism 'meleng oa motho, mehlala e meng ea liteko e kenyelletsa karoloana ea S9, e leng motsoako oa enzymatic ho tloha ho li-microsomes tsa sebete sa rat.
4. 4. Incubation le Khōlo: Lipoleiti li kenngoa ka 37 ° C ka lihora tse 48, ho lumella likolone tsa baktheria hore li hōle haeba liphetoho li etsahala tse tsosolosang motsoako oa histidine.
5. 5. Ho Bala Likolone le Tlhahlobo: Palo ea likolone tse khutlelang morao (libaktheria tse ileng tsa boela tsa khona ho hlahisa histidine) li baloa 'me li bapisoa le lipoleiti tsa taolo.
6. Tlhaloso ea Liphetho

• Positive Ames Test: Keketseho e kholo ea likolone tse khutlelang morao ha li bapisoa le taolo e fana ka maikutlo a hore motsoako o etsa hore ho be le liphetoho, ho bolelang hore ho na le mutagenic le thepa e ka 'nang ea e-ba kankere.
• Teko e mpe ea Ames: Haeba ho se na keketseho e kholo e bonoang, motsoako o ka 'na oa se ke oa e-ba oa mutagenic tlas'a maemo a teko.
• Tekanyetso - Kamano ea Karabelo: Litekanyetso tse phahameng tse lebisang ho eketseha ha maemo a phetoho li matlafatsa bopaki ba mutagenicity.

Qetello

Teko ea Ames ke mokhoa o potlakileng le o sebetsang hantle oa ho lekola boleng ba N-Nitrosamines. Ka lebaka la kamano ea bona le mofets'e, ho tsebahatsa thepa ea bona ea mutagenic ka tlhahlobo ena ho bohlokoa bakeng sa taolo ea taolo le tlhahlobo ea kotsi. Teko ena e lula e le motheo oa tlhahlobo ea chefo le tlhahlobo ea polokeho ea lik'hemik'hale.

Mantsoe a bohlokoa: N-Nitrosamines, NDSRIs, OECD 471, tlhahlobo ea Ames e ntlafetseng, Hamster sebete S9, li-enzyme tsa Cytochrome P450, Teko ea Phetoho