Malachite green is an organic compound that is used as
a dyestuff
and controversially as an antimicrobial in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper.
Why is malachite green used as a primary stain?
Since malachite green is
water-soluble and does not adhere well to the cell
, and since the vegetative cells have been disrupted by heat, the malachite green rinses easily from the vegetative cells, allowing them to readily take up the counterstain. The staining procedure is here.
What is malachite green stain used for?
Malachite Green is used for
bacterial spore staining
by Schaeffer and Fulton’s method. It can also be used as a simple stain for bacterial cells and in place of methyl-green in Pappenheim stain, when combined with Gram stain.
Why is malachite green used in Endospore staining?
When more favorable conditions arise the endospore germinates, again forming a viable vegetative cell. The presence of endospores in a bacterial culture can be detected by staining with malachite green. Because the
endospore coat is so tough, steam is used to enable dye penetration
.
What is the purpose of malachite green when performing a structural stain?
What is the purpose of Malachite green stain? Malachite green is forced into the spore by steaming the bacterial emulsion.
It will stain the endospore, but not the outer wall
.
How long does it take malachite green to work?
Typically cures ich in 24 hours, treatment can be repeated in 24-48 hours, if necessary. If fish experience stress, change 50% of the water. Sometimes treatment will take
10 days
to fully irradiate infestations.
Is malachite green toxic to humans?
The toxicity of this dye increases with exposure time, temperature and concentration. It has been reported to cause carcinogenesis, mutagenesis, chromosomal fractures,
teratogenecity and respiratory toxicity
.
Is malachite green positive or negative?
Thus, commonly used basic dyes such as basic fuchsin, crystal violet, malachite green, methylene blue, and safranin typically serve as
positive
stains. On the other hand, the negatively charged chromophores in acidic dyes are repelled by negatively charged cell walls, making them negative stains.
How do you make malachite green stain?
1) Prepare a
smear on a clear, dry glass slide
. 2) Allow it to air dry and fix it with gentle heat. 3) Flood the slide with 1% w/v Malachite Green (S020). 4)Allow the stain to be in contact with the smear for 2-3 minutes and heat the preparation for 3-6 minutes and then allow to cool.
What color do bacteria stain?
Gram-positive bacteria have a thick mesh-like cell wall made of peptidoglycan (50–90% of cell envelope), and as a result are stained
purple by crystal violet
, whereas gram-negative bacteria have a thinner layer (10% of cell envelope), so do not retain the purple stain and are counter-stained pink by safranin.
How do you make malachite green for Endospore staining?
- Malachite green 0.5% (this is the primary stain) – It can simply be prepared using 0.5 grams of malachite green with 100 ml of water.
- Tap/distilled water (decolorizing agent)
How do you know if an endospore is present?
Lastly, in endospore staining, Vegetative cells will be stained red by the safranin counter stain. If endospores are present in the sample, these
will retain the malachite green stain, and appear bluish-green in color
.
Which bacteria are spore forming?
Spore-forming bacteria include
Bacillus (aerobic) and Clostridium (anaerobic) species
. The spores of these species are dormant bodies that carry all the genetic material as is found in the vegetative form, but do not have an active metabolism.
Why are vegetative cells are not stained green after Endospore staining protocol?
Principle of Dorner’s method for staining endospores
Since the counterstain nigrosin is negatively charged, bacterial cells
don’t easily take up the counterstain
. Therefore, vegetative cells appear colorless, endospores stain red, and the background is black.
What is the importance of Endospore staining?
The main purpose of endospore staining is
to differentiate bacterial spores from other vegetative cells and to differentiate spore formers from non-spore formers
.
What makes Mycobacterium resistant to staining?
What makes Mycobacterium resistant to staining?
Mycobacterium has a waxy cell wall that contains mycolic acid
, a complex lipid that prevents stains from penetrating the cell. … The secondary stain in the acid-fast stain is methylene blue.
