Microbial experiments, what are the microbial experiments

A blank slate? Are they all colonies? If so, the bacterial solution you used when coating the plate is too thick, so that the colonies cannot be separated from each other and are connected together.

In addition, the coating rod or inoculation ring used for coating should touch the inside of the upper lid of the petri dish for a while after burning, and then contact the bacterial solution after cooling, otherwise it is easy to burn the bacteria.

After taking your clothes, I'm sure you will pour the sample directly onto the medium after taking the sample, which is not correct, the sample must be diluted, otherwise the colony density is very high and it will be connected into one piece.

1.First of all, you have to design a medium according to the bacteria you want, so that only the bacteria you want can survive on the medium as much as possible, and if you don't consider the type of bacteria, only the number of them, you can use a whole nutrient medium.

2.Then calculate the total volume of the sample solution, take 1ml out of it and put it into a sterilized test tube, add 9ml of liquid medium, shake well, and the bacterial solution is diluted 10 times. Then take 1ml of liquid from this test tube and add it to another sterile test tube, add 9ml of liquid medium to this new test tube, at this time the bacterial solution in the new test tube is diluted 100 times, repeat, and go on until it is diluted 100,000 times.

3.Then, take 1ml of each of the bacterial solutions in the above test tubes and inject them into the solid medium (at this time, it is equivalent to diluting 10 times on the basis of the dilution of each test tube), apply it evenly with a sterilized coating rod, and carry out the culture.

Finally, find the medium with better colony dispersion, count the colonies, and multiply by the dilution factor (including the 10x in step 3) and then by the total volume of your sample to get the total number of bacteria.

Note: The above manipulations must be performed under sterile conditions.

: No need to inoculate, the strain ** comes?

1. Strain problem.

2. Concentration problem, dilution is recommended!

Microbial experiments include antimicrobial susceptibility test, hemagglutination test, PCR, neutralization test cavity and Wrightl staining.

Antimicrobial susceptibility testing is mainly used to determine the efficacy of a drug by measuring the range of the bacteriostatic zone. Hemagglutination tests determine the antibody titer of the virus by measuring the concentration of its reaction with red blood cells. PCR is the determination of the species of bacteria by 16SRRNA, mainly by 16sRRNA.

The neutralization experiment mainly determines the dilution concentration of the virus. The Gram stain determines whether it is Gram positive or negative. Wright staining is mainly for bacterial staining.

The basic experimental technology of microbiology is moist heat sterilization method, which refers to the method of sterilization with saturated water vapor, boiling water or circulating steam, because the latent heat of steam is large, the penetration is strong, and it is easy to denature or coagulate the protein, so the sterilization efficiency of this method is higher than that of dry heat sterilization, and it is the most commonly used sterilization method.

Boiling sterilization method: boiling water to 100 degrees Celsius and holding for 5-10 minutes can kill bacterial propagules and 1-3 hours to kill spores. When adding 1% to 2% sodium bicarbonate to water, the boiling point can reach 105 degrees Celsius, which can enhance the sterilization effect and can also remove pollution and rust.

This method is suitable for eating utensils, knives and arrows, silver vertical slides and syringes.

Uses of Microbiology Experiments:

Detect microorganisms in food and drinking water, microbial contamination in food and drinking water can cause foodborne diseases, and microbial experiments can detect the presence of bacteria, fungi, viruses and other microorganisms, so as to protect public health and safety.

Detect microorganisms in the environment, microorganisms can reflect the pollution in the environment, such as the total number of colonies in the air, bacteria in the soil, algae in the water, fungi, etc., microbial experiments can help monitor and evaluate the state of environmental hygiene. Medical diagnosis, microbiological experiments can help doctors determine the presence of specific bacteria or viruses in the patient's body, so as to determine the corresponding ** protocol.

Microbial experiments are also an important means to study the morphology, physiology, metabolism, and genetics of various microorganisms in the field of microbiology. Quality control in the pharmaceutical process, the production of many drugs requires the use of microorganisms, such as penicillin, streptomycin, etc., microbial experiments can ensure that the microorganisms in the drug meet certain standards and will not cause harm to the human body. Bona.

The experiments performed in the microbiology laboratory are as follows:

Antimicrobial susceptibility testing is mainly used to determine the efficacy of a drug by measuring the range of the bacteriostatic zone.

Hemagglutination assay: The antibody titer of the virus is determined by measuring the concentration of the virus in response to red blood cells.

PCR: Bacteria determine the macro-closed species of their bacteria mainly by 16srRNA.

The neutralization experiment mainly determines the dilution concentration of the virus.

Gram stain: Determine whether it is Gram positive or negative.

Wright staining is mainly for bacterial staining.

The main uses of the microbiology laboratory:

A microbiology laboratory is a place where microbial research is conducted. According to the safety requirements and use requirements of the microbiology laboratory, it should be different from the general laboratory engineering or purification engineering. Laboratories mainly used in microbiology, biomedicine, biochemistry, animal experiments, genetic recombination, and biological products are collectively referred to as biosafety laboratories.

The biosafety laboratory is composed of the main functional laboratory, other laboratories and auxiliary functional rooms. The biosafety laboratory must ensure personal safety, environmental safety, waste safety and sample safety, and can operate safely for a long time, and at the same time, it also needs to provide a comfortable and good working environment for laboratory staff. <>

Detection of airborne microorganisms.

1) Objectives of the experiment (1) To understand the distribution of microorganisms in the air. (2) Compare the number and type of microorganisms present in the air of ordinary laboratories and clean rooms. and (3) validating the importance of aseptic manipulation in microbiology experiments.

2) Experimental Principle There are a wide variety and a large number of microorganisms in the environment around us. In the air is no exception. Although the air is not a good environment for microorganisms to inhabit.

However, due to the flow of air, dust and water foam, the movement of people and animals, etc., a considerable number of microorganisms are still present. When individual micro-organisms in the air fall on the surface of a solid medium suitable for their growth and reproduction, after being cultured at the right temperature for a period of time, each scattered cell or spore will form a visible cell population, that is, a colony. By observing the colonies of different sizes and shapes, we can roughly identify the types of microorganisms present in the air.

In this experiment, the microorganisms present in the air of the general laboratory and the sterilized clean room were detected, so as to judge the disinfection effect of the clean room and understand the common microbial groups in the air.

3) Experimental equipment (1) Medium: 1) Beef paste peptone medium. 2) Potato sucrose medium. (2) Equipment: several sets of sterile plates, alcohol lamps, incubators, etc.

4. Experimental method (1) Inverted plate: Configure the above medium according to the usual method, divide it into triangular bottles, and autoclave it for later use. Before use, melt the medium, cool it to about 50, and pour several plates for later use.

2) Detection: Turn on the ultraviolet lamp in the sterile room first, and turn it off after irradiation for 15min. Open the lid of the condensed sterile plate and expose it to IH in the clean room space and in the unoccupied normal laboratory space, respectively, and close the lid.

Plates of each medium are required to have 3 replicates per space. (3) Culture: The bacterial medium plate and the fungal medium plate were placed in the incubator of 37 and 28 respectively, and the continuous observation began after 1-2 days, and the order of colonies of different categories and the changes of colony size, shape, color, dry and wet were noted.

If it is a strain in other environments, such as soil, vegetation, animal hair, and household utensils, a small amount of more than one sample can be taken and shaken in sterile water for half an hour, and then the supernatant can be applied to the surface of the sterile plate.

The commonly used instruments and equipment in the microbiology laboratory include ultra-clean workbenches, incubators, balances, microbial homogenizers, colony counters, microwave ovens, electric stoves, autoclaves, pipettes, low-temperature refrigerators, biological safety cabinets, etc

1. Ultra-clean workbench.

The culture of microorganisms is aseptically cultured in a specific medium, so the aseptic culture must provide a sterile working environment on a clean bench.

2. Incubator.

There are many types of incubators, and their role is to provide a suitable environment for the growth of microorganisms. The biochemical incubator can only control the temperature and can be used as a plate culture for general bacteria; The mold incubator can control the temperature and humidity and can be used as a mold culture; CO2 incubators are suitable for the cultivation of anaerobic microorganisms.

3. Balance <>

Balances are used to accurately weigh a wide range of reagents. Electronic balances are commonly used in laboratories, and there are different levels of accuracy depending on the level.

4. Microbial homogenizer.

It is used to extract bacteria from solid samples. The preparation of microbial test samples with microbial homogenizer has the characteristics of no pollution, no damage, no heating, no sterilization treatment, no need to wash utensils, etc., which is a more convenient instrument to use in microbial experiments.

5. Colony counter.

A colony counter assists the operator in counting the number of colonies. Accurately obtain the number of colonies by magnifying, taking pictures, counting, etc. Some high-performance colony counters can also be connected to a PC for automatic counting.

6. Microwave oven electric stove.

It is used for rapid heating of solutions, heating and dissolving of microbial solid medium.

7. Autoclave.

Most of the experimental items, reagents, and culture media used in microbiology should be strictly sterilized and sterilized. Sterilizers are also available in different sizes, some are manual and some are fully automatic. Users need to choose according to their own needs.

8. a pipette.

Liquid measuring devices are used to accurately measure all kinds of liquids. Common liquid measuring devices include graduated cylinders, pipettes, microdispensers, graduated test tubes, and beakers.

9. Low-temperature refrigerator.

Refrigerators are indispensable for storing reagents and samples in the laboratory. Some of the reagents used in microbiology experiments are required to be stored at 4 degrees, and some are required to be stored at minus 20 degrees.

10. Biological safety cabinet.

Some of the reagents and sample microorganisms involved in microbiological experiments are toxic and harmful to operators. In order to prevent the spread of harmful suspended particles and aerosols, the biological safety cabinet can be used to provide safety protection for operators, samples and cross-contamination between samples and the environment.