Method for culturing and observing plaque

Abstract

The invention relates to a method for culturing and observing plaque. The method takes escherichia coli as a host, separates bacteriophage and cultures the plaque, and comprises the following steps: pre-detecting a water sample, preparing a bacterial suspension, treating the water sample and proliferating the bacteriophage, diluting a bacteriophage proliferating solution, preparing a bacteriophage-host mixed solution, culturing the plaque by a sandwich plate method, conducting dyeing and observing and the like, so as to finally observe clear plaque. Escherichia coli moss is in a light blue cloud shape, and plaques are dark blue transparent small circular plaques one by one. Compared with a traditional double-layer plate method, the method has the advantages that the operation difficulty of the experiment is remarkably reduced, the risk of polluting other environmental microorganisms is reduced, the success rate of the experiment is improved, and the method is a good teaching experiment method and can be applied to college teaching or related technician training. The sandwich plate method disclosed by the invention can also be used for culturing and observing plaque formed by other bacteriophages, but related steps need to be adjusted.

Description

technical field [0001] The invention belongs to the technical field of microbes and relates to a method for culturing and observing phage plaques. Background technique [0002] Bacteriophage (phage) is a virus that infects prokaryotes such as bacteria, actinomycetes, and cyanobacteria. It is a common experimental material for genetics, molecular biology, and genetic engineering, and widely exists in various habitats in nature. According to whether they lyse the host after infecting the host, they can be divided into virulent phages and mild phages. Potent phages will infect the host and form plaques with certain shape, size, edge and transparency on the lawn. Because the plaques of each phage have a certain shape, it can be used as an identification index of phages, and can also be used for the isolation and counting of pure species. [0003] The separation and purification of bacteriophage is one of the must-do items in courses such as general microbiology experiments, pa...

AI Technical Summary

Problems solved by technology

[0004](1) Use the pre-thawed upper medium to mix the host and phage, the temperature is difficult to control

If it is lower than 45°C, the upper layer of agar will solidify during the mixing process. If it is higher than 60°C, the phages may be inactivated, so beginners are often in a hurry, and the upper layer of agar is prone to agar blocks due to solidification

[0005](2) Difficult to observe with naked eyes

Although the bottom medium is used to make up the level to avoid the unevenness of the bottom of the glass petri dish, but because the colonies of Escherichia coli are colorless and translucent, the agar is transparent and pale yellow, and it is difficult for beginners to identify phage plaques only by visual observation

[0006](3) The culture medium is rich in nutrients and has high requirements for the experimental environment and operating techniques, and is easily polluted by other microorganisms in the environment, which interferes with the experimental results

[0007](4) Strict observation time

However, the upper layer of agar is soft (0.7%), has low hardness, and the E. coli colony is not tightly combined with the medium, so it is easy to wash up the bacterial lawn or destroy the upper layer of medium during the staining process, and then it is impossible to observe and count the plaques

Images