2 to Bacterial growth Microorganisms divided due to their sensitivities to O 2 into Aerobic bacteria the bacteria that grow in the presence of oxygen Obligate or strict anaerobes can grow only in the absence of O ID: 914325
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Slide1
lab9
. Relationship of O
2
to Bacterial growth
Microorganisms divided due to their sensitivities to O
2
into:
Aerobic bacteria
the bacteria that grow in the presence of oxygen
Obligate or strict anaerobes
can grow only in the absence of O
2
and are harmed by its presence.
Facultative anaerobes
can grow either aerobically or anaerobically (in the presence or in the
abscence
of O
2
)
Aerotolerant
anaerobes
are microorganisms that cannot use O
2
,
Microaerophiclic
microorganisms
, that require small amounts of O
2
, but are inhibited at normal atmospheric tension of O
2
Capnophilic
bacteria
the bacteria that need 5-10%
CO
2
. see (fig. 20).
Figure (20) Appearance of various agar deep culture
Slide3The principles of Anaerobic Jar use
There are another ways (method) for cultivation or culturing of anaerobic bacteria one of them is the
Gaspak
Anaerobic system (fig. 26).
In this system, hydrogen and CO
2
are generated by
Gaspak
envelope after addition of water .A palladium catalyst (pellets) in the chamber lid catalyzes the formed H
2
with O
2
to form water.
Palladium Catalyst
2H
2
+ O
2
--------------→ H
2
O
By this reaction quantity of O2 in the chamber is completely reduced. Therefore the environment inside the chamber becomes anaerobically and convenient for the grow of the anaerobic microorganisms. Sometimes instead of
Gaspak
(H
2
and CO
2
) generator it can be used a flamed wax candle to reduce the O
2
inside the Jar chamber. The Anaerobic jar must be tightly closed.
-The inoculated agar plates incubate at 37°c for 24-48 hours.
- Observe the isolated colonies record the results in your report.
Slide4Slide5Slide6Figure (
21)
Anaerobic cultivation in anaerobic jar
Slide7The anaerobic culture media
Eugon
Agar (PH 7.0).
Tryptose
15.0
gm
;
soytone
5.0
gm
; Dextrose 5.0
gm
; L-
cystine
0.2
gm
; Sodium Chloride 4.0
gm
;sodium sulfite 0.2
gm
;Agar 15.0
gm;Distilled
water 1 liter.
Thioglycollate
broth (PH 7.0)and agar.
Peptone 15.0
gm
; yeast extract 5.0
gm
; Dextrose 5.0
gm;L-cystine
0.75
gm
;
thioglycolate
0.5
gm
;
NaCL
2.5
gm;Methylenc
or
Resazurin
0.001
gm
; Dist. Water 1.0 L.
15
gm
agar added for
thioglycollate
agar.
Isolation of Anaerobic bacteria from the soil
Or Dental specimens (infected root canal or plaque
etc
).