Question

Which of the following stain is used to prepare the smear of Lactobacillus?

Answer 1

Staining is an additional method used to increase contrast in the microscopic picture in microscopy. In biology and medicine, stains and dyes are commonly used to display structures in biological tissues for viewing, often with the assistance of various microscopes. Lactobacillus belongs to the community of bacteria that ferment and, in the absence of oxygen, turn the sugars into lactic acid.

Complete answer:Lactobacilli bacteria is found in milk that is untreated. In the presence of already synthesized curd, this bacterium may also be added to milk where it multiplies and lactose sugar becomes lactic acid. The developed lactic acid gives a sour taste and the milk is converted to curd. These species are found in curd in very large numbers.
Although staining will seem a little more difficult than most of the procedures, if the instructions are followed correctly, it will prove to be a simple procedure. This would also be an important method that would enable the researcher to compare slides that are stained and unstained.
Steps in preparing lactobacillus smear and its observation under the microscope are as follows:
1. With the toothpick, take a very tiny drop of yoghurt and smear it on the slide for 2 to 3 seconds.
2. On a microscope slide, place a small drop of the methylene blue solution. Gloves to wear.
3. On top put a coverslip. Remove the excess solution with a paper towel or tissue around the coverslip. 4. First, display the compound microscope at 4 x or 10 x before switching to greater magnification. Even at the highest magnification, Lactobacillus bacteria will appear tiny.
5. The Methylene blue stain is then used to prepare the lactobacillus smear.
So, 'Methylene blue' is the right answer.

Note: While yogurt bacteria can be treated responsibly in the laboratory, protection is still encouraged since one is still in contact with glass slides and stains. Besides that, while preventing clutter in the working room, gloves should be used at all times.