Saturday, 21 February 2015

Why saline solution is used for the preparation of serial dilution of microorganisms in microbiology?

Saline solution is used for the preparation of culture suspension or serial dilution in microbiology. Saline is 0.9 % sodium chloride solution. Culture suspensions are prepared in saline solution because 0.9 % sodium chloride solution is isotonic in nature. In isotonic solution the concentration of solutes remains the same both inside and outside of the microbial cell and cells remains at their usual osmotic pressure. But water is hypotonic in nature in which the concentration of solute is greater inside the cell than outside and due to this water try to enter inside the bacterial cell. The osmotic pressure develop on the bacterial cell which can damage the bacterial cells during serial dilution. That's why serial dilution is prepared in 0.9% saline solution.

Thanks and have a nice day!

15 comments:

  1. If negative control fails what to do? and how investigation to be done sir? please explain

    ReplyDelete
    Replies
    1. If negative control fails, it means there might be problem with the testing environment, handling problem or problem in the accessories used for the analysis. In that case investigation shall be done why negative control failed? You can investigate with check list or using different tools like why why analysis or fish bone diagram.

      Delete
    2. In which condition hypertonic saline is used for dilution in place of normal saline? And why?

      Delete
  2. Why most of the bacterial colony on the agar surface is circular????

    ReplyDelete
  3. Why most of the bacterial colony on the agar surface is circular????

    ReplyDelete
  4. May I know which solution can be used as buffer or maintaining osmotic pressure for serial dilution based isolation of fungi or specifically fungal endophytes from plant tissues?

    ReplyDelete
  5. could you explian why we are keeping microbial plates in inverted position?

    ReplyDelete
  6. could you explian why we are keeping microbial plates in inverted position?

    ReplyDelete
    Replies
    1. If v keep the plates in upright position in incubator then water content from agar get evaporated and get accumulated on the lid of the plate in form of vapours. These vapours get condensed and again fall down on agar plate.. this may cause contamination and if there are some Microbial colonies on the plate then they got spreaded due to condensed water droplet fallen down on colony surface. Datz why v r incubated the media plates in inverted position.

      Delete
  7. we are using scdm for the serial dilution is it OK.

    ReplyDelete
  8. How do you check the pathogenicity of bacteria?

    ReplyDelete
    Replies
    1. Its v simple way to test, reinoculate the isolated bacterial strain on its host, second way to extract the genomic DNA of bacterial strain and amplify the pathogenic genes which are responsible for production of pathogenic compounds/symptoms for cause the disease

      Delete
  9. Useful information.

    ReplyDelete
  10. i cant understand properly plz explain in simply why use 0.9% Normal salin is use

    ReplyDelete