detection of mutation by bacteria salmonella typhymurium.this test was discovered by Bruce Ames.

1. Made by: Manoah Prakash Ram
SoS In Biotechnology
Pt.Ravishankar Shukla University
Raipur(C.G)

2. CONTENTS
 Introduction.
 About Mutation.
 Chemicals Mutagens.
 Some products with chemical mutagens.
 About Ames test
 History and Basic Idea
 Process of Ames test
 Importance and Application of Ames test in
Biotechnology.
 References

3. Introduction
• Bacteria are often
known as harmful
organism.
•But originally they are
research guinea pigs.
•This is due to their
availability, fast
reproduction and
metabolic activity.

4. Bacteria can prevent cancer
 Bacteria have many application in the field of science.
 One of them is they can prevent cancer from happening.
this is possible by Ames test.
 But first we should know how cancer are caused.
 Any mutation that alters the normal functioning and division of cell is
termed as cancer.
 And these mutation may be caused internally or by Carcinogens.
 This must be kept in mind that all the cancers are made by mutations
but all the mutations are not cancers.
 Before moving further we should know what is mutation.

5. Mutation
•In most easy Language
any change in the
sequence of DNA is
called as Mutation
•These DNA sequence
are like guidelines to
cell.
•Any change in the DNA
sequence cause messing
up of instructions.
•And blocks the normal
functioning of the cells

6. ..

7. Causes of mutation
 By radiation
 The source can be of
Many types:
 By sun
 By Uranium
 By Microwaves
 X-rays
 Etc.

8. Chemicals Mutagens
 Some mutation can also be caused by the components
they are called as mutagens.
 These mutagens can be chemical or biological.
 But in these topic we are going to discuss about the
chemical mutagens.
 These chemical mutagens migrate inside the cell and
mutate the host DNA.

9. Some Products with possible mutagens
•Air fresheners
•Air freshener contains
many chemicals like:
•Acetaldehyde
•1-4,dichlorobenzene
•Methylpyrrolidone
•1-3 dichloro-2 propanol
•These chemicals can
cause mutation in
bronchiolar cells of
lungs

10. Some Products with possible mutagens
•Birth control pills
•Many components in
birth control pills are
carcinogenic.
•It can cause breast
cancer, cervix and ovary
cancer.

11. Some Products with possible mutagens
•Nail polish
•Nail polish contain
many products one of
them is Dibutyl
phthalate
•When they are used in
access they can cause
basal cell carcinoma,
malignant carcinoma
and dermal cancers

12. Some Products with possible mutagens
•Lead
•Recent ban on maggie
is due to the amount of
lead found in it.
•Lead damages almost
everything inside out
body.
•The most bizarre
consequence is
adenocarcinoma
(stomach cancer)

13.  Ethylene bromide which is used to set leaded gasoline to vaporize them
and send them to engine and exhaust.
 Ziram used to prevent fungus disease in plant is also carcinogenic.
 Some medical drugs like isoniazide which show mutagenic properties
in biological system.
 AF-2 once used in Japanese food product is carcinogenic in nature.
 Saccharine used in sugar-free can be carcinogenic but they do not give
positive Ames test.
 Safrole used as flavoring in beer is also mutagenic in nature.
And many more

14. How to tell that product is carcinogenic or not?
 That is why the Ames test came into existence.
 In Ames test a special strain of salmonella typhimurium is
used which is histidine lacking.
 These histidine lacking bacterial strain cannot grow on its
own.
 The chemical mutagen is then added to the nutrition
media. this mutagen revert back the action of histidine
producing gene and they start their normal functioning.
 If the bacterial sample show growth in the media plate
having chemical mutagen this show the test is positive ,if
growth is not obtained then test is negative.

15. History of Ames test
•Ames test was brought
forward by Bruce Ames
in 1970.
•He is professor in
university of
california,berkely.
•In department of
biochemistry.
•He developed this
method because
previous methods were
expensive and time
consuming.

16. Ames test procedure
 in this test the salmonella typhimurium strain is used
which is mutant.
 The mutation is the histidine synthesis' gene so the
bacteria is called as (his-) histidine minus strain.
 This strain of bacteria cannot grow without histidine
amino acid.
 When the bacteria is inoculated in the media plate
without histidine amino acid in them they are unable
to grow even if they are placed in suitable environment
for prescribed time.

17.  But here the case is for chemical mutagens.
 As we are using his- strain of bacteria. this bacteria cannot
grow on normal media plate.
 But if the chemical is mutagen is added in the media plate
 this chemical mutagen will turn the his- gene to his+ gene.
due to the activity of mutagenic chemical compound.
 Now due to the mutation this bacterial strain will produce
their own histidine and can grow on plate.
 This type of mutation is called as back mutation.

18. Pictogram of Ames test

19. But it is not that simple.
 There are some chemicals that are non mutagenic,but
they become mutagenic when they come in contact in
body metabolism.
 So to see that rat liver extract is mixed with the
nutrient media.
 And then the bacterial sample is inoculated.
 But from the idea the negative test will not show any
growth, but the growth can occur due to spontaneous
mutation.
 And this is the only limitation of this test.

21.  Spontaneous mutation can give us false positive result.
 So to understand the difference between spontaneous
mutation and mutagenicity.
 If the bacterial colony are obtained scattered they show
that bacteria is there because of spontaneous mutation.
 And if the colony are aggregated they show that the
mutagenicity is brought forward by the chemical
mutagens.
 But if you get scattered colony you should cross check your
experiment.
 But if the media plate is blank this is the confirmation that
the chemical is non mutagenic.

22. Negative Ames test Positive Ames test

23. Importance
 Ames test is important nowadays because the amount
of chemical product used today can be carcinogenic.
 Ames test are usually applied in the pharmaceutical
industry prior to using them in animal and human,if
the sample fails in Ames test its production is stopped.
 Many organic product which are thought to be safe for
the human use are termed carcinogenic in Ames test
 Many cosmetics are now first tested in Ames test
before their commerial production.

24. Application in Biotechnology
 Smoker urine test for mutagenicity is possible by the
use of Ames test.
 Primary DNA damage test can be done through Ames
test
 This test is highly sensible for testing the mutagenicity
of water and solid soil sample from the nuclear war
zone. by Muta-chromoplate kit.
 Type analysis of soil and petroleum product for
mutagenicity.

25. References
 Prescott’s Microbiology (Textbook by Christopher J. Woolverton, Joanne M.
Willey, and Linda Sherwood.
 Bruce N. Ames; William E. Durston; Edith Yamasaki
Frank D. Lee (1973).Review paper.
 Wikipedia On Ames test.
 NCBI on applications.
 Study.com for lectures and pictures
 Kimbley’s biology paper US