How do you change the colour of a bacteria? Do you use a specific chemical?

Question: How do you change the colour of a bacteria? Do you use a specific chemical?
- Keywords:
  bacteria,
  chemical,
  colour
Asked by Vicky to Carmen, Daniel on 9 Mar 2015.
- Carmen Denman answered on 9 Mar 2015:
  
  Hi,
  
  Vicky great question. It may not happen to the naked eye, but using a microscope I have changed the color of bacteria by introducing a green fluorescent protein into the bacteria encoded on a plasmid (bit of DNA that likes moving around). this green protein when excited with a specific wavelength of light will fluoresce green. It originally was discovered as a protein from jelly fish I think. Read about it here and see the image:
  
  http://www.gettyimages.co.uk/detail/photo/fluorescence-photograph-of-jellyfish-high-res-stock-photography/108439201
  
  You can also use different types of stains, like crystal violet or saffrin to color dead bacteria. There are lots of options out there to change the color of bacteria, depending on what you want to study. .
  
  Cheers,
  
  Carmen

Question: How do you change the colour of a bacteria? Do you use a specific chemical?