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10 Cards in this Set
- Front
- Back
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Lowenstein Jensen Medium (L. J. Medium)
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is used for the isolation and cultivation of Mycobacterium species
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Developed by
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The original formulation of Lowenstein Jensen media was developed by Lowenstein who incorporated congo red and malachite green to inhibit unwanted bacteria
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Composition
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Ingredients Gms / 600 ml L-
Asparagine 3.600 Monopotassium phosphate 2.400 Magnesium sulphate 0.240 Magnesium citrate 0.600 Potato starch, soluble 30.000 glycerol 12 ml Malachite green 0.40 Distilled water 600ml
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Principle
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Potato starch soluble and glycerol provide fatty acidsand protein required for the metabolism of mycobacteria.
Thecoagulation of the egg albumin during sterilization providesa solid medium for inoculation purposes. Monopotassium Phosphate and Magnesium Sulfate enhance organism growth and act as buffers. - See more at: http://laboratoryinfo.com/lj-medium/#sthash.tg7i7yz7.dpuf Malachite greenselectively inhibits contaminants. |
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Incubation condition |
Lowenstein Jensen Media require incubation in a5-10% CO 2 atmosphere in order to recover mycobacteria.Mycobacteria, for unknown reasons, are not recovered well from candleextinction jars at 35°C
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Jensen's modification
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The present formulation, a glycerated egg-based medium, is based upon Jensen's modification.
It eliminates congo red and uses a moderate concentration of malachite green to prevent growth of the majority of contaminants surviving decontamination of the specimen. |
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Gruft Modification
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Gruft Modification formula is the same as the LJ formulation except for the addition of penicillin, nalidixic acid and ribonucleic acid (RNA). Nalidixic acid and penicillin inhibit most of the gram-negative bacteria. RNA serves as a growth stimulant for the increased isolation rate of mycobacteria.
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Precaution when using Mycobacterium |
Processing all specimens and cultures in a biological safety hoodand autoclaving all used media and supplies is especially important whenworking with mycobacterial cultures.
It is recommended that biochemical and/or serological tests beperformed on colonies from pure culture for complete identification.
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Limitation LJof media |
Lowenstein Jensen, Selective media contain cycloheximide which is considered a potentially hazardous chemical
Protect the media from all sources of light, as malachite green isvery photosensitive. Selective mediaoften inhibit, to some extent, specific strains of organisms for which they aredesigned to select. |
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For more information |
microamaze.blogspot.com
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