The microbial knowledge you want
Microorganisms are a group of tiny organisms that exist widely in nature and are invisible to the naked eye and must be magnified hundreds, thousands or even tens of thousands of times with the help of an optical microscope or an electron microscope. They have the advantages of small size, simple structure, rapid reproduction, easy variation and strong ability to adapt to the environment.
Classification of microorganisms：
There are many kinds of microorganisms, at least more than 100,000 kinds. According to their structure, chemical composition and living habits and other differences can be divided into three categories.
Eukaryotic microbial cell nucleus has a higher degree of differentiation, including nuclear membrane, nucleolus and chromosomes; cytoplasm has complete organelles (such as endoplasmic reticulum, ribosome and mitochondria, etc.). Fungi belong to this type of microorganism.
Prokaryotic microbial cells have a low degree of nuclear differentiation, only primitive nucleoplasm, no nuclear membrane and nucleolus; organelles are not very complete. There are many species of such microorganisms, including bacteria, spirochetes, mycoplasma, rickettsia, chlamydia and actinomycetes.
Acellular microorganisms have no typical cell structure and no enzyme system to generate energy, and can only grow and reproduce in living cells. Viruses belong to this type of microorganism.
Separation and purification of microorganisms
A microbial culture containing more than one species is called a mixed culture. If all cells in a colony are derived from one parental cell, then the colony is called pure culture. In the identification of bacterial species, the microorganisms used are generally required to be pure cultures. The process of obtaining pure culture is called separation and purification, and there are many methods.
1. Pour plate method
First, the microbial suspension is diluted in a series, and a certain amount of the dilution is fully mixed with the dissolved nutrient agar medium maintained at about 40-50°, and then the mixture is poured into a sterile petri dish. After solidification, the plate was incubated upside down in a constant chamber. A single cell is multiplied to form a colony, a single colony is taken to make a suspension, and the above steps are repeated several times to obtain a pure culture.
2. Coating flat plate method
First, the microbial suspension is properly diluted, and a certain amount of the dilution is placed on a sterile nutrient agar plate that has solidified, and then the dilution is evenly spread on the surface of the medium with a sterile glass spatula. A single colony can be obtained by incubation at a constant temperature.
3. Plate scribing method
The easiest way to isolate microorganisms is streaking. Streak a small amount of the culture on the plate using a sterile loop. There are many methods of scribing. The common scribing methods that are more likely to appear a single colony are the slash method, the curve method, the square method, the radiation method, and the four-grid method. When the inoculation loop moves backward on the surface of the medium, the bacterial liquid on the inoculation loop is gradually diluted, and finally a single cell is scattered on the drawn line. After culture, each cell grows into a colony.
4. Enrichment culture method
The method and principle of enrichment culture method are very simple. We can create conditions that allow only the desired microbes to grow, and under these conditions the desired microbes can effectively compete with other microbes and far exceed other microbes in terms of growth ability. If some obligate parasites are to be isolated, the samples must be inoculated into the corresponding susceptible host cell populations to grow in large numbers. Pure parasitic bacteria can be obtained by repeated seeding.
5. Anaerobic method
In the laboratory, in order to isolate some anaerobic bacteria, a test tube containing the original medium can be used as a culture vessel, and the test tube can be heated in a boiling water bath for several minutes to expel the dissolved oxygen in the medium. It is then rapidly cooled and inoculated. After inoculation, sterile paraffin was added to the surface of the medium to isolate the medium from the air. Another method is to replace the gas in the medium with N2 or CO2 after inoculation, and then seal the mouth of the test tube over a flame. Sometimes in order to isolate some anaerobic bacteria more efficiently, the isolated sample can be inoculated on the medium, and then the petri dish can be placed in a completely sealed anaerobic culture device.
6. Single cell (or single spore) isolation method
It is to take microseparation method to directly isolate single cells or single individuals from mixed populations for culture to obtain pure culture. For larger microorganisms, a single individual can be extracted using a capillary. For microorganisms with relatively small individuals, a micromanipulator is required to pick single microbial cells or spores with a capillary or microneedle, hook, loop, etc. under the microscope to obtain pure culture. The single-cell separation method has relatively high requirements on the operation technology.
Microbial culture
1. According to whether oxygen is needed during culture, it can be divided into two categories: aerobic culture and anaerobic culture.
Aerobic culture: also known as "aerobic culture". That is to say, when this microorganism is cultivated, it needs oxygen to be added, otherwise it will not grow well. In the laboratory, slant cultures are obtained by obtaining sterile air from the outside through cotton plugs. Most of the liquid culture in the Erlenmeyer flask is shaken by a shaker, so that the outside air can continuously enter the bottle.
Anaerobic culture: Also known as "anaerobic culture". Such microorganisms do not require oxygen to participate in the cultivation. In the cultivation process of anaerobic microorganisms, the most important point is to remove the oxygen in the medium.
2. According to the physical state of the medium, it can be divided into two categories: solid culture and liquid culture.
Solid culture: It is a method of inoculating the strains into a loose and nutrient-rich solid medium, and culturing microorganisms under suitable conditions.
Liquid culture: In experiments, liquid culture can make microorganisms multiply rapidly and obtain a large number of cultures. Under certain conditions, it is also an effective method for microorganisms to select and enrich bacteria.
BKMAM biotech provides corresponding laboratory consumables for microbial culture:
Disposable plastic round/square petri dishes:
lHigh transparency polystyrene material (PS);
lThe surface is smooth and flat, and there is no optical distortion of cells under microscope observation;
l Stacking design makes stacking and storage easier;
l Ethylene oxide sterilization (EO);
l Wear and corrosion resistance.
Disposable Plastic Inoculation stick/loop:
Polystyrene material (PS);
Anti-pollution, Endotoxin,DNase,RNase and pyrogens free;
Independent packaging has been sterilized;
Fine workmanship and complete specifications;
Disposable Plastic cell spreader,bacteria spreader:
Polystyrene material (PS);
Anti-pollution, Endotoxin,DNase,RNase and pyrogens free;
L-shaped design, easy to use;
One-time use, light and convenient.
Stainless Steel / Disposable Sterile Specification Plates:
The stainless steel specification plate is made of stainless steel, and the disposable specification plate is made of food-grade polypropylene (PP).
Anti-pollution, Endotoxin,DNase,RNase and pyrogens free;
The smearing area is strictly standardized
One side of the specification plate is equipped with a handle, which is easy to operate
Sterile sealed single package to avoid secondary contamination of sampling and error in results
One-time use to avoid cross-contamination and reduce workload
Welcome to cooperate with us
Sincerely
Michael Peng
michael@bkmbio.com