Inverted plates. Bacterial cultures. Molecular biology
In biological experiments, I believe that everyone often has to invert plates, bacterial culture, molecular biology experiments, etc. In pharmaceutical companies, inverted plates are even more commonplace. Environmental monitoring, water monitoring, microbial inspection, etc., beginners are often not good at it. Now summarize a few tips for your reference:
First, to prevent condensation when pouring dishes:
1. Experienced people know that the palm of the hand is not hot and the back of the hand is hot. This is an empirical data. At this time, the temperature is around 45 degrees, which is most suitable for inverted plates.
2. If you want to pour multiple dishes in a row, it is often easy to solidify, especially in winter. Once solidified, you need to heat it to a higher temperature to dissolve (the characteristics of the vitreous body). So it is recommended to have a 50-degree constant temperature water bath open at this time, and put the triangular bottle containing the culture medium in at any time. The effect will be much better.
Second, there is condensation in the petri dish.
Generally speaking, there will be a few drops, which have little effect. If there are too many, you need to pay attention. The approximate situation is:
1. Before pouring the dish, it is best to keep the flat dish at a temperature of 35-40 degrees (the tentacles have a warm feeling).
2. Keep the flat dish standing at a higher ambient temperature.
Third, pour the cooled oneagar medium：
It is quite troublesome to melt the cooled medium again, because roasting on an electric stove requires not only patience, but also care. If you are not careful, you will wet the cork; put it back in the sterilization pot for heating, which is good, but it is too troublesome. The solution is to heat it in a microwave oven, which is fast and good, melts thoroughly, and uses it with confidence. Of course, the triangular bottle used for the medium must be able to be put into the microwave oven: 250ml.
What should I do without a microwave oven? Be careful when using an electric stove. When directly heating and melting the nutrient agar on the electric stove, you should pay attention to applying a low heat when melting to the last thin layer left on it, and heat it slowly to prevent the gas from breaking through the thin layer and causing a burst. The nutrient agar rushes out of the triangle bottle.
Fourth, the inverted flat plate maintains uniformity: a disposable flat plate diagram of daily water
The pouring plate should be shaken three times on the left and three times on the right. Be careful not to stain the lid of the plate and shake it lightly.
V. Specific treatment:
The previous points mentioned that the optimum temperature for inverted flat dishes should be maintained at 35-40 degrees, but the quality of agar of different brands is different. Also, according to the formula in the national standard, the agar content is 1.5%. Some agar solidifies quickly, some solidify more slowly, and the ambient temperature is low, and the agar solidifies faster. According to the actual situation, the content of agar should be adjusted appropriately. When the room temperature is low, the amount of medium agar we prepare is less, and when inverted and mixed, the action should be faster. If the room temperature is too low, you can also put the petri dish in the oven and heat it properly (about 40 degrees).
Sixth, avoid bubbles:
Some students report that bubbles will be generated when inverting the plate, mainly following the above points, heating should not be too high, just melt, strengthen the operation practice, and pour slowly, preferably against the wall of the flat plate.
