In the pure-bred isolation and inoculation technology of bacteria, the matters needing attention are as follows: dilution. In purebred separation, the bacterial liquid is diluted to a certain gradient and coated on, for example, LB medium.

If the dilution is not good, the bacteria will grow too densely, or the bacteria will not grow at all. The optimum dilution gradient is that the number of colonies on the plate is between 30 and 300. At this time, the morphology of colonies can be clearly seen, which is convenient for picking a single colony.

Basic form and size:

There are the following types:

① Monococcus: it exists alone, such as Micrococcus urealyticum;

② Dicoccus: such as pneumococcus;

③ Streptococcus: such as Streptococcus lactis;

Tetracoccus: the four cells formed are arranged together to form a word, such as tetraccocci;

⑤ Eight cocci: such as urea spores;

⑥ Staphylococcus: such as Staphylococcus aureus.

Rod-shaped or long rod-shaped bacteria with great difference in length and width, such as Bacillus subtilis and Clostridium; Branched or bifurcated bacteria, such as Bifidobacterium; Bamboo-shaped (both ends are cut off), such as Bacillusanthracis. ?

Baidu encyclopedia-bacteria