Upload
sreeremya-sree
View
94
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Anaerobic environment,hungate technique,microbes involved in 4 stages aidogenesis,acetogenesis,methanogenesis
Citation preview
ANAEROBIC ENVIRONMENT
BY SREEREMYA.S
Also microaerophiles like Campylobacter jejuni very important in medial terms
For proper diagnosis and for studies of anaerobic environments culture techniques are desirable
Culture of anaerobes is extremely difficult due to the need to exclude oxygen, slow growth and complex growth requirements
Molecular methods based on DNA analysis and direct microscopy have shown that we are largely ignorant of the microbial world and previously unknown diversity has been discovered
Culture methodsAnaerobes differ in their sensitivity to oxygen
and the culture methods employed reflect this - some are simple and suitable for less sensitive organisms, others more complex but necessary for fastidious anaerobes
Vessels filled to the top with culture medium can be used for organisms not too sensitive
Most common adaptation of media is the addition of a reducing agent, e.g. thioglycollate, cysteine
Acts to reduce the oxygen to water, brings down the redox potential -300mV or less.
Can add a redox indicator such as rezazurin, pink in the presence of oyxgen - colourless in its absence
Deep culture tubes can be used to test whether an unknown organism is anaerobic/facultative or aerobic
Thioglycollate added to culture medium, oxygen only found near top where it can diffuse from air -pattern of colony formation characteristic of organisms
REDOX POTENTIAL