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11Biotechnology and Engineering
High school biotechnology and engineering knowledge is sorted out, and the application of traditional fermentation technology, fermentation engineering and its applications, microbial culture technology and applications, etc. are summarized.
Edited at 2024-01-06 20:42:26
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11Biotechnology and Engineering
- Valentine's Day marketing campaign
This Valentine's Day brand marketing handbook provides businesses with five practical models, covering everything from creating offline experiences to driving online engagement. Whether you're a shopping mall, restaurant, or online brand, you'll find a suitable strategy: each model includes clear objectives and industry-specific guidelines, helping brands transform traffic into real sales and lasting emotional connections during this romantic season.
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10Biotechnology and Engineering
1 Application of traditional fermentation technology
1The concept of fermentation
Fermentation is a process in which people use microorganisms to convert raw materials into products needed by humans through microbial metabolism under appropriate conditions.
Traditional fermentation technology
Source of bacteria
Microorganisms that naturally exist in raw materials or in dough, milk and other fermented products preserved from previous fermentation
type
solid fermentation
semi-solid fermentation
substance
Oxidative decomposition of substances under aerobic or anaerobic conditions
result
Produce various fermentation products that people need
application
Production of fruit wine, fruit vinegar, pickles, soy sauce, etc.
Traditional fermented food production
Preparation of bean curd
principle
Proteins are broken down into small molecules of peptides and amino acids under the action of proteases
Fat is broken down into glycerol and fatty acids by the action of lipase
participating microorganisms
Mucor
filamentous fungi
sporogeny
Heterotrophic aerobic type
kimchi making
principle
Glucose is broken down into lactic acid by enzymes
step
Salt water configuration
Use clean water and table salt to prepare brine with a mass fraction of 5% to 20%
Boil and cool
Vegetable processing
Wash and cut fresh vegetables into cubes or strips, mix well and dry
Install the altar
Put vegetables into kimchi jar
Add garlic cloves, ginger and other spices when the jar is halfway through
Continue to fill until 80% full
seal
Slowly pour the cooled salt water into the jar until all the vegetables are covered with the salt water, then cover the jar with the lid.
fermentation
Like filling the water tank on the edge of the altar lid with water
Pay attention to frequently replenishing water in the tank during the fermentation process.
Control fermentation time according to indoor temperature
Changes in substance content
Early fermentation
middle stage of fermentation
Late stage of fermentation
Production of fruit wine and fruit vinegar
1Principles and conditions
1 Fruit wine making
1 fermentation bacteria
1 yeast
2 metabolic types
1 Heterotrophic facultative anaerobic type
3 fermentation process
1 Aerobic conditions
1 Mass reproduction through aerobic respiration
2 anaerobic conditions
1Production of alcohol through anaerobic respiration
4. Oxygen demand
1Preliminary oxygen demand
2 No need for oxygen in the later stage
5 product testing
1 smell
1 smells like alcohol
2 tasting
3Potassium dichromate solution under acidic conditions changes from orange to gray-green
4 observations
1 has bubbles and foam
2 turbid
5 Determine pH
6 Perform microscopic examination of yeast
2 fruit vinegar production
1 fermentation bacteria
1acetic acid bacteria
2 metabolic types
1 Heterotrophic aerobic type
3 fermentation process
1When oxygen and glycogen are sufficient
1 Directly convert glucose into acetic acid
2 Sufficient oxygen, lack of sugar source
1Convert alcohol to acetic acid
4. Oxygen demand
1 always needs oxygen
5 product testing
1 smell
1 has a sour taste
2 tasting
3Acid-base indicator
1 pH test paper
4 observations
1No air bubbles and foam
2 Turbidity, white bacterial film forming on the liquid surface
5. Perform microscopic examination of acetic acid bacteria
6 Speed up the production of fruit vinegar
1. Buy vinegar, open it and expose it to the air. After a period of time, a bacterial film will appear on the surface. Inoculate
2 Operation steps and purposes of fruit wine and fruit vinegar
1Utensil disinfection
1 operation
1. Clean fermentation bottles, juicers and other equipment with dish soap
2 Disinfect with 70% alcohol by volume and let dry for later use.
2 purposes
1. Prevent contamination of fermentation liquid
2Rinse the grapes
1 operation
1. Take fresh grapes, rinse them with water 1 to 2 times, remove branches and rotten seeds, and drain them.
2 purposes
1 Prevent flushing away wild yeasts on grape skins
2. Prevent contamination of fermentation liquid
3. Rinse first and then remove the stems to avoid skin damage caused by removing the stems first.
3 Juicing
1 operation
1 Use a juicer to squeeze the grape juice and put it into the fermentation bottle, leaving about 1/3 of the space, and close the bottle cap.
2 purposes
1 Prevent fermentation liquid from overflowing
2Enable yeast to carry out aerobic respiration and multiply
4Alcoholic fermentation
1 operation
1. The fermentation temperature is strictly controlled at 18~30℃
2The time is controlled within 10~12 days
3 Loosen the bottle cap every 12 hours or so
2 purposes
1Create anaerobic environment for alcohol fermentation
2 Prevent aerobic microorganisms from contaminating the fermentation broth
5 Acetic acid fermentation
1 operation
1Open the bottle cap and cover with a layer of gauze
2 Fermentation temperature is 30~35℃
3The time is controlled within 7~8 days
2 purposes
1Create an aerobic environment for acetic fermentation
2 Fermentation engineering and its applications
The concept of fermentation engineering
Harnessing the specific functions of microorganisms
through modern engineering technology
Produce products useful to humans at scale
Basic steps of fermentation engineering
Selected strains
Filter from nature
Obtained through mutation breeding and genetic engineering
Expand training
Bacteria need to be expanded before fermentation
Configure culture medium
According to the bacterial species, select raw materials to prepare the culture medium
Sterilize
Strict sterilization of culture media and fermentation equipment
Vaccination
Inoculate the bacteria into the culture medium and cultivate them
fermentation
Detect the number of microorganisms and product concentration in the culture medium at any time
Add essential nutrients in a timely manner
Strictly control fermentation conditions such as temperature, pH and dissolved oxygen
Separate and purify products
microbial cells
Use methods such as filtration and sedimentation to separate and dry the bacteria
Metabolites
Extraction, separation and purification based on the properties of the product
Get product
Beer industrial production process
process
germination
Barley seeds germinate and release amylase
baking
Heat kills seed embryos but does not inactivate amylase
grind
Grind dry malt into malt powder
Saccharification
Starch breaks down to form syrup
steaming
produce flavor components
Sterilize
Terminator further action
fermentation
Yeast converts sugar into alcohol and carbon dioxide
disinfect
Kills most microorganisms
Extend shelf life
termination
filter
adjust
Pack beer for sale
The difference between craft beer and industrial beer
craft beer
Whether to add food additives
no added
Fermentation scale
small scale
Fermentation time
Long fermentation time
Yield
Low Yield
price
high price
regular beer
Whether to add food additives
Add to
Fermentation scale
large scale
Fermentation time
Short fermentation time
Yield
High Yield
price
low price
Characteristics of fermentation engineering
raw material
Rich sources of raw materials
low price
condition
Mild production conditions
product
Product specificity
waste
Waste causes little pollution to the environment and is easy to dispose of
Fermentation Engineering Applications
food industry
Traditional fermented products
food additives
Enzyme
Pharmaceutical industry
Obtain microorganisms with certain drug-producing capabilities
Directly transform the strains and then mass-produce the required products through fermentation technology
Genetic engineering is used to transfer one or several antigen genes of the pathogen into appropriate microbial cells, and the expression product obtained can be used as a vaccine.
Agriculture and animal husbandry
Produce microbial fertilizers
pesticide
feed
Other applications
Utilize fiber waste fermentation to produce alcohol, ethylene and other energy substances
extremophiles
Thermophilic bacteria, Halobacteria, can be used to produce detergents
Psychrophilic bacteria help increase production of heat-sensitive products
3 Microbial culture technology and applications
Preparation of culture medium
concept
According to the different needs of microorganisms for nutrients and substances, people prepare nutrient substrates for their growth and reproduction.
use
Cultivate, isolate, identify, preserve microorganisms or accumulate their metabolites
type
According to physical state
liquid culture medium
Features
No coagulant, liquid state
use
industrial production
solid medium
Features
Contains coagulant and is in solid state
such as agar
use
Isolation and identification of microorganisms, viable bacteria technology, strain preservation
By use
Select media
Features
Allow certain types of microorganisms to grow
Also inhibits or prevents the growth of other types of microorganisms
use
Isolation of desired microorganisms from numerous microorganisms
Example
Add penicillin to isolate yeast and mold
identification medium
Features
According to the metabolic characteristics of microorganisms, certain indicators or chemicals are added to the culture medium to produce specific colors or other changes.
use
Identify different types of vitamins
Example
Identification of Escherichia coli using eosin-methylene blue medium
Element
carbon source
definition
Substances that provide element C
effect
Substances and some metabolic products that make up the cells of living organisms
Sometimes it is also an energy substance for heterotrophic organisms.
source
Inorganic carbon source
carbon dioxide
sodium bicarbonate
organic carbon source
carbohydrate
beef paste
Nitrogen source
definition
Some substances that provide N elements
effect
Synthesize proteins, nucleic acids and other substances
source
Inorganic nitrogen source
Nitrogen
Ammonia
Ammonium salt
Nitrate
organic nitrogen source
Peptone
Inorganic salt
definition
Provide microorganisms with various important elements besides carbon and nitrogen, including macroelements and trace elements
effect
Provide inorganic nutrients to microorganisms
Adjust culture medium pH
source
inorganic compounds
Sodium chloride
Potassium hydrogen phosphate
water
definition
The most abundant inorganic compound in living organisms
effect
good solvent
Participate in chemical reactions
source
medium
metabolite
Other physical and chemical properties
pH
Mold
Acidic
bacteria
Neutral or weakly alkaline
special nutrients
When cultivating Lactobacilli, vitamins need to be added to the culture medium
oxygen
When cultivating anaerobic microorganisms, anaerobic conditions need to be provided
Aseptic technique
disinfect
condition
Mild physical, chemical or biological methods
result
Only kills some of the microorganisms on or inside the object
Common methods
boiling sterilization
articles for daily use
Pasteurization
Liquids that are not resistant to high temperatures
Chemical disinfection method
operating space
Operator's clothing and hands
UV disinfection method
vaccination room
inoculation box
Ultra clean workbench
biological disinfection
definition
A method of using organisms or their metabolites to remove some microorganisms in the environment
Sterilize
condition
Strong physical and chemical methods
result
Kills all microorganisms inside and outside objects, including spores and spores
Common methods
moist heat sterilization
medium
container
dry heat sterilization
glassware
metal utensils
Sterilization by burning
Vaccination tools
Purpose
The essential
Prevent bacterial contamination
Other operations
Before the experiment, the operating space operators should be disinfected, and the utensils and culture media used should be sterilized.
After disinfection and sterilization are completed, care should be taken to avoid contact between sterilized materials and utensils and surrounding items.
In order to avoid contamination of microorganisms in the surrounding environment, many of the following operations should be performed on a clean workbench and near the flame of an alcohol lamp.
Pure culture of microorganisms
definition
Cultures
A population containing a specific type of microorganism formed under appropriate conditions by inoculation into a culture medium
pure culture
Microorganisms obtained from the reproduction of a single individual
colony
Dispersed microorganisms multiply on the surface or inside a suitable solid culture medium to form a population of daughter cells that are visible to the naked eye and have a certain morphological structure.
pure culture
The process of obtaining pure cultures
process
Configure culture medium
Weigh 200 grams of peeled potatoes and cut into cubes
Add 1000ml of water and heat to boil
gauze filter
Add 20 grams of glucose
Add 15~20g agar
Dilute to 1000ml with distilled water
Adjust pH
If necessary, the pH of the culture medium can be adjusted after dilution and before sterilization.
Sterilize
Media sterilization
moist heat sterilization
Petri dish sterilization
dry heat sterilization
pour slab
condition
When the culture medium cools to about 50 degrees, pour the plate near the flame of the alcohol lamp.
step
Remove the cotton plug from the Erlenmeyer flask
Pass the bottle mouth quickly through the flame
Use your thumb and forefinger to open a gap slightly larger than the mouth of the petri dish. Pour the culture medium into the culture dish and immediately close the lid.
Wait for the culture medium to cool and solidify, then place the culture dish upside down.
Precautions
Agar is a polysaccharide that melts above 98°C and solidifies below 44°C. When pouring the plate, it will be hot if the temperature is higher than 50℃. If the temperature is lower than 50℃, the agar will solidify if not handled in time.
You can touch the Erlenmeyer flask containing the culture medium with your hands. When you feel that the temperature of the Erlenmeyer flask has dropped to a point where it is no longer hot to the touch, you can pour it into a flat plate.
Inoculation and isolation
plate marking method
principle
By continuously streaking the surface of the solid culture medium with an inoculating loop, the accumulated bacterial strains are gradually diluted and dispersed on the surface of the culture medium. After several streakings, single bacterial colonies can be dispersed and cultured.
Vaccination tools
inoculation loop
step
Place the inoculation loop on a flame and burn it until the metal wire of the inoculation loop burns red
Cool the loop over a flame while removing the cotton plug from the test tube containing the yeast culture.
Pass the test tube orifice through the flame
Dip an inoculating loop into the bacterial solution near the flame.
Pass the mouth of the test tube through the flame and plug it with a cotton plug
Open a gap in the open lid near the flame, use an inoculating loop to quickly draw 3 to 5 parallel lines on the surface of the culture medium, and cover the lid.
After the burning inoculation loop has cooled down, start the second scribing line from the end of the first scribing line.
Repeat the above operation to make 345 lines.
Be careful not to connect the last stroke with the first stroke
advantage
Observe the characteristics of bacterial colonies and separate mixed bacteria
shortcoming
Can't count
dilution coated plate method
Serial dilution operation
time
Before seeding cells into culture medium
step
Cells are dispersed by liquid dilution. As the degree of dilution increases, the number of microbial cells per unit volume decreases and the cells are dispersed.
Coating plate operation
step
Take 0.1ml of bacterial solution and add it dropwise to the surface of the culture medium
The applicator is immersed in a beaker of alcohol
Burn the applicator on the flame, wait until the alcohol burns out and the applicator cools down before applying
Use a spreader to evenly spread the bacterial solution on the surface of the culture medium
When coating, the petri dish can be rotated to ensure even coating.
Vaccination tools
spreader
advantage
can count
Colony characteristics can be observed
shortcoming
Complex operation
Need to coat multiple panels
What the two purification methods have in common
Solid media are used
Aseptic operation is required
will form a single colony on the surface of the culture medium
can be used to observe colony characteristics
Cultivate yeast
method
Invert the inoculated plate and an uninoculated plate and place them in a constant-temperature incubator.
condition
Around 28℃
time
24~48 hours
microbial count
microscopic direct counting method
principle
Count the number of microorganisms in a certain volume of sample using a specific bacterial technology plate or a hemocytometer under a microscope.
method
Count with a counting board
shortcoming
Unable to distinguish between dead bacteria and live bacteria, resulting in larger count results
indirect counting method
principle
When the dilution of the sample is high enough, a single colony growing on the surface of the culture medium may originate from a viable bacteria in the sample dilution.
By counting the number of colonies on the plate, you can estimate how many viable bacteria there are in the sample.
Precautions
In order to ensure accurate results, plates with a colony count of 30 to 300 are generally selected for counting.
shortcoming
The number of colonies counted is often less than the actual number of viable bacteria. This is because when two or more cells are connected together, only one colony is observed on the plate.
Experimental operation on isolation and enumeration of urea-decomposing bacteria in soil
1Experimental principle
1The reason why bacteria in the soil can decompose urea is because they can synthesize urease
2. Configure a culture medium that is the only nitrogen source for beverages. The bacteria that can grow in this culture medium are bacteria that can decompose urea.
2Experimental process
1Soil sampling
1 Dig topsoil from moist soil with a pH close to neutral, and take a soil layer 3 to 8 cm from the surface.
2. Dilution of sample
1 Usually, a certain dilution range of sample liquid is used for culture to ensure that a plate with a colony count of 30 to 300 is obtained for proper counting.
3 Culture and observation of microorganisms
1 vaccination
1. Inoculation by dilution coating method
2Cultivation conditions
1The temperature is 30~37℃
2Cultivation for 1~2 days
3 observations
1 Distinguish microorganisms based on the characteristics of their colonies
4 count
1 Count the number of colonies every 24 hours
2Select the records when the number of colonies is stable as the result
4 calculations
1 Calculate the number of cells per unit volume
3 Analysis and evaluation of experimental results
1. Judgment of whether there is bacterial contamination
1. No bacteria grew in the petri dish of the control group.
1 Not contaminated by bacteria
2. Miscellaneous bacteria grew in the petri dish of the control group.
1Contaminated by bacteria
2. Does the culture medium have a screening effect?
1. The number of colonies on the selection medium is much less than the number of colonies on the beef extract and peptone medium.
1 Selection medium has a screening effect
3 Sample dilution evaluation
1 Obtain three or more plates with colony numbers between 30 and 300
1 operation successful
Results of 4 replicate groups
1Compare each replicate group
1If the same soil sample is selected, the statistical results should be similar.
5. Identification of isolated strains
1Principle
1Urease synthesized by bacteria that decompose urea can decompose urea into ammonia
2 Ammonia will make the culture medium more alkaline
1 analysis
1. Add a red indicator to the culture medium and culture the bacteria. If the indicator turns red
1 Determine that the bacteria can decompose urea
cell engineering
Overview
Principles and methods
Apply principles and methods from multiple disciplines such as cell biology, molecular biology, and developmental biology
Operation level
organelle level
cellular level
organizational level
Purpose
Obtain specific cells, tissues, organs, individuals or their products
Classification
Plant cell engineering
Totipotency of plant cells
definition
After cells divide and differentiate, they still have the potential to produce a complete life form or differentiate into various other cells.
reason
Every cell in an organism contains a complete set of genes needed to develop into a complete individual
size comparison
A fertilized egg is larger than a germ cell, larger than a somatic cell
Less differentiated cells are larger than highly differentiated cells
Plant cells are larger than animal cells
reflect
Plants can be reproduced using a petal, a grain of pollen, or even a cell of the plant.
Failure and reasons
During the growth and development of organisms, not all cells exhibit totipotency
Selective expression of genes in cells under specific time and spatiotemporal conditions
performance conditions
in vitro
Nutrients
hormone
Suitable temperature and pH
Plant tissue culture technology
definition
The technology of cultivating isolated plants, organs, tissues and cells on an artificially prepared medium and giving them suitable culture conditions to induce them to form complete plants.
Theoretical basis
Totipotency of plant cells
Glossary
callus
It is an amorphous parenchyma mass formed by dedifferentiation of explants.
embryoid body
Roots, shoots, etc. formed by callus redifferentiation
basic process
dedifferentiation
Inoculated explants
Isolated plant organs, tissues and cells, etc.
callus induction
Amorphous parenchyma mass formed by induced dedifferentiation of differentiated cells
redifferentiation
induced budding
The ratio of auxin to cytokinin content is less than 1
induced rooting
The ratio of auxin to cytokinin content is greater than 1
Transplant survival
The specific process of tissue culture of chrysanthemum
Material selection
Plants that reproduce easily asexually
aloe vera
Begonia
Rose
chrysanthemum
Explant disinfection
Rinse with running water
Disinfect with 70% alcohol by volume for 30 seconds
Wash with sterile water 2 to 3 times
Treat with sodium hypochlorite solution for 30 minutes
Wash with sterile water 2 to 3 times
Vaccination
Cut the explant into 0.5~1 cm long segments
Insert 1/3~1/2 of the explant into the callus induction medium
Seal the mouth of the bottle with sealing film or bottle cap and mark it properly
Pay attention to the direction of the explant when inoculating, do not insert it upside down
Morphologically, the upper end faces upward.
nourish
Place it in an incubator at 18~22℃
After 15 to 20 days, transfer to the culture medium for inducing sprouting.
After the sprouts grow, they are transferred to the medium for rooting induction and further induced to form test tube seedlings.
Roots must be regenerated by buds first. If the order is reversed, it will be difficult to induce buds by inducing roots first.
environmental control
high humidity
low light
constant temperature
Refining seedlings
Before transplanting, open the sealing film or bottle cap and let the test tube seedlings grow in the incubator for a few days.
Provide strong light and harden the seedlings in closed bottles to promote the transformation of the seedlings into autotrophic seedlings.
reason
The photosynthetic ability of test tube seedlings is weak
transplant
After flushing the culture medium from the roots with running water, transplant the seedlings into an environment such as sterilized vermiculite or perlite, and allow them to grow stronger before transplanting them into the soil.
cultivation
After transplanting the seedlings, observe and record the growth of the seedlings every day
Water and fertilize timely until flowering
Precautions
Aseptic processing
Culture media and all instruments used in the laboratory must be sterilized
The vaccination operation must be carried out next to the flame of an alcohol lamp
Instruments must be sterilized after each use
Lighting
Lighting is generally not required during callus induction.
In the subsequent cultivation process, appropriate time and intensity of light need to be provided every day
Plant somatic cell hybridization technology
definition
A technology that fuses plant cells from different sources under certain conditions to form cells and culture them into new plants.
principle
somatic hybridization
cell membrane fluidity
Hybrid cells are grown into hybrid plants
Totipotency of plant cells
process
Cellulase and pectinase remove the cell wall to form protoplasts
protoplast fusion
physical method
Electrofusion method
centrifugation
chemical method
PEG fusion method
High calcium ion-high pH is the fusion method
regenerate cell wall
Fusion completed sign
Hybrid cell plant tissue culture
Quantitative relationship
The number of chromosomes, the number of chromosome groups, and the genotype are all added directly.
significance
Break reproductive isolation, achieve distant hybrid breeding, and cultivate new plant varieties
limitation
At present, there are many unresolved theories and technologies, and hybrid plants cannot yet express the characteristics of their parents according to people's needs.
Applications of Plant Cell Engineering
New ways to propagate plants
rapid reproduction
technical means
Plant tissue culture technology
principle
Totipotency of plant cells
advantage
Achieve mass propagation of seedlings efficiently and quickly
Maintain the genetic characteristics of premium breeds
Features
Use less material
Short cultivation period
High reproductive rate
Suitable for automated management and conducive to factory production
Crop detoxification
technical means
Plant tissue culture technology
Material selection
Near the top meristematic area of the plant (such as the stem tip)
reason
This part has very few or even no viruses
advantage
Virus-free crops have high yield and good quality
Cultivation of new crop varieties
haploid breeding
principle
Chromosomal variation
advantage
Significantly shorten the breeding life
process
Anthers are cultured in vitro to produce haploid plants
Artificially induced chromosome doubling
Utilization of mutants
principle
Gene mutation
advantage
Generate new genes to significantly improve certain traits
process
Explants dedifferentiate and form callus
Mutagenesis of callus-forming mutants
Screening of induced weathering mutants creates new varieties
Factory production of cell products
secondary metabolites
definition
subtopic
type
Phenols
Terpenes
Nitrogen-containing compounds
technical means of production
advantage
animal cell engineering
animal cell culture
Animal cell culture conditions
Nutritional conditions
Carbohydrates, amino acids, inorganic salts, vitamins, growth-promoting factors, trace elements and other nutrients
Usually some natural ingredients such as serum are also needed
Sterile and non-toxic environment
Sterilize culture fluid and culture equipment
performed under sterile conditions
Change the culture medium regularly to remove metabolites
Temperature, pH and osmotic pressure
Gas environment
95% air
Oxygen is necessary for cell metabolism
5% carbon dioxide
Maintain pH of culture solution
The process of animal cell culture
Take pieces of animal tissue and disperse them into individual cells
mechanical method
chemical method
Trypsin
Collagenase
Add culture medium to prepare cell suspension
Bottle primary culture
suspension growth
Direct centrifugation collection
Adherent growth
First use trypsin to disperse them into single cells, and then centrifuge to collect them.
contact inhibition
Excessive cell density, accumulation of harmful metabolites, and lack of nutrients
Subculture in bottles
principle
Cell Proliferation
application
Artificial skin components
Large-scale production of animal secreted proteins
Stem cell culture and its applications
embryonic stem cells
source
early embryo
Features
Can differentiate into any kind of cell, tissue or organ, and even become an individual
application
Differentiate into cardiomyocytes, neurons and hematopoietic stem cells, etc.
adult stem cells
source
bone marrow, cord blood
Features
differentiate into specific cells and tissues
application
Hematopoietic stem cells used to treat leukemia
Neural stem cells used to treat Parkinson's disease, Alzheimer's disease
induced pluripotent stem cells
source
somatic cells
Fibroblasts
Features
Can be induced to differentiate into cells similar to embryonic stem cells
application
Treating sickle cell anemia, Alzheimer's disease, cardiovascular disease
animal cell fusion technology
concept
A technology that combines two or more cells to form one cell
method
PEG fusion method
Electrofusion method
Inactivated virus induction method
structural basis
cell membrane fluidity
result
Form a hybrid cell that shares the genetic information of the original two or more cells
significance
Breaking through the limitations of sexual hybridization methods and making distant hybridization possible
It has become an important method for studying cell genetics, cell immunity, tumors and cultivating new biological varieties, and has opened up new ways to produce monoclonal antibodies.
application
Monoclonal antibodies
Preparation principle
B cells
One B cell secretes only one specific antibody
myeloma cells
Able to proliferate in large quantities in vitro
hybridoma cells
It can both increase value in large amounts and produce sufficient amounts of specific antibodies.
Preparation Process
A variety of B cells are obtained from the spleens of immunized mice injected with specific antigens
Culture myeloma cells
induced fusion
1st screening
Reason for screening
After inducing fusion, a variety of hybrid cells will be obtained, as well as unfused cells.
Screening method
Screen with specific selection media
2nd screening
Reason for screening
Since mice are also subject to other anti-cancer stimuli in their lives, the hybrids obtained through selective culture have cells that can produce other antibodies in the flow cells.
Screening method
Culture in multi-well petri dishes
clonal culture
Antibody testing
Screen multiple times to obtain a population of cells that can produce antibodies to specific genes
Inject into the abdominal cavity of mice or culture in vitro to obtain monoclonal antibodies
application
as diagnostic reagents
Play an important role in the diagnosis of various diseases and antigen detection
transporting drugs
Antibody drug conjugates achieve selective killing of tumor cells by combining plasma cell toxins with monoclonal antibodies that can specifically recognize tumor antigens.
structure
Antibody
Connector
drug
Animal somatic cell nuclear transfer technology and animal cloning
Concept analysis
Donor
The nucleus of an animal cell
receptor
oocyte with nucleus removed
result
The recombined cells develop into a new embryo, which then develops into an individual animal
principle
Animal body cells are totipotent
Mammalian Nuclear Transfer Types
embryonic cell nuclear transfer
Easier to succeed
somatic cell nuclear transfer
process
Taking donor bovine somatic cells for culture
Oocytes were collected from bovine ovaries at the slaughterhouse and cultured in vitro to meiotic metaphase II oocytes.
Enucleated
object
spindle-chromosome complex
method
In the case of penetrating the zona pellucida of the oocyte
microinjection
The most commonly used method
Without penetrating the zona pellucida of the oocyte
Enucleated
gradient centrifugation
DNA denaturation
UV rays for short periods of time
chemical handling
Donor cells injected into enucleated oocytes
The electrofusion method allows the donor and recipient oocytes to form reconstructed embryos.
Use physical or chemical methods to activate the reconstructed embryo to complete cell division and development processes
The embryos are transferred to the surrogate cow and finally the cloned cow is obtained
Application prospects
animal husbandry
Accelerate the process of genetic improvement of livestock and promote high-quality, flock-promoting breeding
Medicine & Health
Producing medical proteins as bioreactors
Cells, tissues and organs from genetically modified cloned animals can be used for xenotransplantation
Human nuclear transfer embryonic stem cells are induced to differentiate and form corresponding cells, tissues and organs, which can be used for organ transplantation
scientific research
Studying cloned animals could provide humans with a deeper understanding of embryonic development and aging processes
By cloning a group of animals with the same genetic background, disease-causing genes can be analyzed by comparing them.
Cloning animals of specific disease models to help study the pathogenic mechanisms and develop corresponding drugs
protect endangered species
Increase the survival of endangered species
There is a problem
Success rate is very low
The vast majority of cloned animals have health problems and display genetic and biological defects
embryo engineering
Concept analysis
Operation object
germ cells
fertilized egg
early embryonic cells
Technology type
in vitro fertilization
Embryo Transfer
embryo segmentation
Early embryo culture
Operation level
Mainly focused on the cellular level
Theoretical basis
Mammalian fertilization and early embryonic development
fertilization
Preparation Phase
sperm capacitation
Completed within the reproductive tract of female animals
Cultivation of sperm in artificially prepared capacitation fluid to capacitate them
capacitation fluid
Element
Varies depending on animal species
Common main ingredients
heparin
Calcium ionophore
Egg preparation
The ability to collect does not develop until metaphase II of meiosis.
fertilization stage
step 1
Main process
The sperm releases a variety of enzymes to dissolve some structures outside the egg cell membrane (such as the zona pellucida, etc.) and contact the egg cell membrane.
Physiological reaction
zona pellucida reaction
effect
Preventing subsequent sperm from entering the zona pellucida is the first barrier to preventing polyspermy from entering the egg and fertilizing it.
Step 2
Main process
The sperm enters the egg and the tail falls off
Physiological reaction
egg cell membrane reaction
effect
Rejecting other sperm from entering the egg is the second barrier to preventing polyspermia from fertilizing the egg.
Step 3
Main process
After the sperm nuclear membrane ruptures, a new nucleus is formed, and the egg is activated to complete meiosis 2 and excrete the second polar body.
signs of fertilization
Formation of male and female pronuclei
Two polar bodies were observed
Step 4
Main process
The male and female pronuclei are fully developed, move towards each other, approach each other, and the nuclear membrane disappears
starting point of ontogeny
form zygote
early embryonic development
process
fertilized egg
starting point of embryonic development
morula
Cell division is mitosis
increased number of cells
The total size of the embryo remains unchanged or slightly reduced
Each cell becomes smaller in size
blastocyst
inner cell mass
The various tissues that develop into the embryo
Trophoblast
develop into fetal membranes and placenta
gastrula
ectoderm
Cell layer on the surface of the gastrula
mesoderm
It is formed by a part of cells between the inner and outer germ layers.
endoderm
Formed by migrating cells within the gastrula
Way
cleavage
Way
Mitosis
Variety
organic matter
The embryo has not established contact with the mother and cannot obtain organic matter from the mother. Respiratory consumption is inhibited, so the total amount of organic matter is reduced.
Cell number and volume
The total volume of the embryo remains unchanged or slightly reduced, but the number of cells increases and the volume of each cell decreases
DNA content in cells
As cells divide, the number of cells increases and the total DNA content increases, but the nuclear DNA content in each cell remains relatively stable.
incubation
concept
The process by which the blastocyst expands further, causing the zona pellucida to rupture and the embryo to stretch out from it.
significance
If it does not hatch properly, the embryo cannot continue to develop.
embryo engineering technology
in vitro fertilization
process
Oocyte collection and culture
The collected oocytes need to be cultured to the m2 stage to mature.
Sperm collection and capacitation
The collected sperm must undergo capacitation before fertilization can occur.
fertilization
Capacitated sperm and cultured mature eggs are fertilized in an appropriate culture medium.
significance
Effective measures to improve animal reproductive capacity
Providing embryos available for embryo transfer
Embryo Transfer
concept
object
Transgenic, nuclear transfer, embryos obtained through in vitro fertilization
process
Transplanted into female animals of the same species and with the same physiological condition
Donor
The embryos are provided by individuals with excellent genetic traits and strong fertility
receptor
The recipients of embryos are individuals with healthy physiques and normal reproductive capabilities.
result
develop into new individuals
Breeding type
sexual reproduction
developed from fertilized eggs
asexual reproduction
Developed from recombinant cells formed by nuclear transfer technology
obtained from embryonic segmentation
Different animals have different embryo transfer times.
Pre-morula
mouse
Rabbit
Morula or blastocyst
ox
sheep
gastrula
Almost all animals cannot be transplanted at the proembryonic stage because the cells are highly differentiated at this time and the success rate of transplantation is very low.
process
Excellent donor cow
Features
Excellent genetic traits
Strong production capacity
operate
Superovulation of excellent donor cows
Use of exogenous gonadotropins to induce the ovaries to release more mature eggs than would occur naturally
Breeding or artificial insemination of fine bulls in estrus
Collect embryos and examine
Breed normally or do another transplant after two or three months
Embryo freezing (-196℃) storage
Embryo Transfer
Recipient cow
Features
Have a healthy physique
Have normal reproductive capacity
operate
Recipient cows undergo estrus synchronization treatment
Use progestins or prostaglandins
Provide the same physiological environment before and after embryo transfer
Perform pregnancy test on recipient
Produce offspring with superior traits
Physiological basic perspective
The embryo can be transferred into the recipient
After mammals are in estrus and ovulate, the physiological changes in the reproductive organs of the donor and recipient of the same animal are the same.
Embryos can be collected
After the early embryos of mammals are formed, they will not establish tissue contact with the mother's uterus for a certain period of time, but will be in a free state.
The embryo survives in the recipient
Recipients basically do not experience immune rejection of foreign embryos transplanted into the uterus
normal embryo development
The donor embryo can establish normal physiological and tissue connections with the recipient uterus, and the genetic characteristics of the donor embryo are not affected
significance
Give full play to the reproductive capabilities of outstanding female individuals
Greatly shortens the reproductive cycle of the donor itself
Significantly increase the number of donor offspring
embryo segmentation
concept
object
early embryo
method
mechanical method
Purpose
Having identical twins or multiple births
Features
Offspring from the same embryo, have the same genetic material
substance
Can be regarded as one of the methods of asexual reproduction or cloning of animals
equipment
Stereomicroscope
Micromanipulator
Material
Well developed morula or blastocyst with normal shape
When dividing embryos at the blastocyst stage, the inner cell mass should be equally divided
significance
Promote the breeding of excellent animal breeds and produce offspring with the same genetic traits, which are valuable materials for genetic research.
Gender identification and genetic disease screening before embryo transplantation play an important role in artificially controlling the gender of animals and breeding healthy offspring.
Genetic Engineering
Overview
means
According to people's wishes, new genetic characteristics are given to organisms through technologies such as genetic modification
Purpose
Create new biological phenotypes and biological products that better meet people's needs
level
molecular level
Because it is designed and constructed at the DNA molecular level, it is also called recombinant DNA technology.
Basic tools of genetic engineering
restriction endonuclease
source
Mainly from prokaryotes
type
There are thousands of isolated restriction enzymes
Features
Recognize specific nucleotide sequences of double-stranded DNA
Break the phosphodiester bonds at specific locations in each chain
effect
breaks the phosphodiester bond between two nucleotides
result
Produce sticky ends and blunt ends
DNA ligase
effect
Sews together double-stranded DNA fragments to restore the phosphodiester bond between the two nucleotides cut by restriction enzymes
type
E.coli DNA ligase
source
E. coli
Function
Suture sticky ends only
T4 DNA ligase
source
T4 bacteriophage
Function
Sew sticky ends and plain ends
carrier
type
Plasmid
Circular double-stranded DNA molecule
Bacteriophages Animal and plant viruses
Features
Has one or more restriction enzyme cleavage sites
After the plasmid carrying the exogenous DNA fragment enters the recipient cell, it can replicate itself in the cell or integrate into the recipient, and the DNA will be replicated synchronously with the recipient DNA.
There are often special marker genes used for screening recombinant DNA molecules.
effect
Carrying foreign DNA fragments into recipient cells
Basic operating procedures of genetic engineering
Screening and acquisition of target genes
target gene
In the design and operation of genetic engineering, genes used to change the characteristics of recipient cells or obtain expected expression products, etc.
Screen for suitable target genes
Screening from related genes with known structures and clear functions is one of the more effective methods.
Screening using sequence databases and sequence alignment projects
Acquisition of target genes
Artificially synthesized target genes
Rapid amplification of target genes using PCR specificity
principle
DNA semi-conservative replication
concept
Based on the principle of DNA semi-conservative replication, a technology that provides various components and reaction conditions involved in DNA replication in vitro to carry out large-scale replication of the nucleotide sequence of the target gene
condition
a certain buffer solution
Magnesium ions
Activate DNA polymerase
DNA template
2 primers
A short, single-stranded nucleic acid that can complementary pair with a base sequence of the parent DNA strand.
4 types of nucleotides
High temperature resistant DNA polymerase
Instruments that can automatically regulate temperature
process
transsexual
When the temperature exceeds 90°C, double-stranded DNA depolymerizes into single strands
Restoration
When the temperature drops to about 50°C, the two primers bind to the two single-stranded DNA through complementary base pairing.
extend
When the temperature rises to about 72°C, the four deoxyribonucleotides in the solution synthesize new DNA strands according to the principle of complementary base pairing under the action of high-temperature-resistant DNA polymerase.
Product identification
agarose gel electrophoresis
Quantitative relationship
Number of DNA molecules
2^n
Number of DNA molecules containing primer a or b
2^n-1
The number of DNA molecules containing both primers a and b
2^n-2
The total number of primers consumed
2^(n 1)-2
Obtain target genes by constructing gene libraries
Construction of gene expression vectors
status
The core of genetic engineering
Purpose
Make the target gene exist stably in the recipient cells and can be passed on to the next generation
Enable the target gene to express and function
Composition and function
target gene
Genes encoding proteins or factors with regulatory effects
Promoter
The site where RNA polymerase recognizes and binds
Can drive genes to be transcribed into mRNA
terminator
The end point of transcription, which plays a regulatory role in the transcription process
marker gene
For screening of recombinant DNA molecules
build process
The plasmid and DNA molecule are cut with the same restriction enzyme or a restriction enzyme that produces the same ends
DNA ligase, ligated into recombinant plasmid
Introduce the gene of interest into the recipient cells
Convert
definition
The process by which the target gene enters the recipient cell and remains stable and expressed in the recipient cell.
Variation type
genetic recombination
Example
Streptococcus pneumoniae transformation experiment
Agrobacterium transformation method
biological species
plant
method
Agrobacterium transformation method
pollen tube passage method
receptor cells
somatic cells
fertilized egg
conversion process
Insert the target gene into the T-DNA of Ti plasmid
Agrobacterium introduced into plant cells
Integrate into the chromosomal DNA of the recipient cell and express
animal
method
microinjection
receptor cells
fertilized egg
conversion process
Purify the expression vector containing the gene of interest
Egg retrieval (fertilized eggs)
microinjection
fertilized egg development
Get animals with new traits
microorganism
method
Calcium ion treatment method
receptor cells
prokaryotic cells
conversion process
Calcium ion treated cells
Put cells in a physiological state that can absorb DNA molecules from the surrounding environment
Gene expression vector introduction
Detection and identification of target genes
Molecular level detection
Whether the target gene is inserted
PCR and other technologies
mRNA
PCR and other technologies
protein
Antigen-antibody hybridization
Individual biological level identification
individual
Insect-resistant and disease-resistant vaccination experiments
Crude extraction and identification of DNA and amplification and electrophoresis identification of DNA fragments
Crude extraction and identification of DNA
Fundamental
DNA is not soluble in alcohol, but some proteins are soluble in alcohol
Initial separation of DNA and proteins
The amount of substance that DNA can dissolve in is a sodium chloride solution with a concentration of 2 mol L^-1
Dissolve DNA
At a certain temperature, DNA appears blue when exposed to diphenylamine reagent.
Identify DNA
Operating procedures
Collect materials, grind
Remove impurities from filtrate
Line the funnel with gauze and filter the grinding solution into the beaker
Place it in the refrigerator at 4°C for a few minutes (or pour the grinding solution directly into a plastic centrifuge tube and centrifuge for 5 minutes)
Take the supernatant again
Precipitation of DNA
Add an equal volume of cold alcohol solution with a volume fraction of 95% to the supernatant.
The movements should be gentle to avoid aggravating the breakage of DNA molecules and preventing the DNA molecules from forming flocculent precipitates.
Let it sit for 2~3 minutes
Use a glass rod to stir in one direction and roll up the filament
The movements should be gentle to avoid aggravating the breakage of DNA molecules and preventing the DNA molecules from forming flocculent precipitates.
Use filter paper to absorb the water above (or pour the solution into a plastic centrifuge tube and centrifuge for 5 minutes, discard the supernatant, and dry the sediment at the bottom of the tube)
DNA identification
Dissolve the filaments or precipitates with two moles per liter of sodium chloride solution
Add diphenylamine reagent
Mix well and place into boiling water and heat for 5 minutes
Observe the color change after cooling
DNA amplification and electrophoresis identification
Experimental basis
PCR principle
DNA thermal denaturation English
electrophoresis
principle
DNA molecules have dissociable groups that can be positively or negatively charged
definition
Under the influence of an electric field, these charged molecules will move toward the electrode opposite to the one they carry.
Common electrophoresis
agarose gel electrophoresis
Factors affecting migration rate
gel concentration
Size and conformation of DNA molecules
PCR operation steps
Pipetting
Use a micropipette to add each component to the microcentrifuge tube in sequence according to the recipe or the instructions of the PCR kit.
mix
Close the lid of the centrifuge tube tightly
centrifuge
Place the micropipette in a centrifuge and centrifuge for about 10 seconds to concentrate the reaction solution at the bottom of the tube
reaction
Set up the cycle program of the PCR machine
Place the microcentrifuge tube containing the reaction solution in the PCR machine for reaction
DNA electrophoresis identification
DNA molecules in the gel can be detected under ultraviolet light with a wavelength of 300 nanometers through staining.
Applications of genetic engineering
basic objects
breast bioreactor
meaning
Allow foreign genes to be specifically expressed in mammalian mammary glands
Using animal mammary tissue to produce pharmaceutical proteins
gene expression
Synthetic drug proteins are identical to natural proteins
receptor cells
animal fertilized eggs
Target gene introduction method
microinjection
production conditions
No need for strict sterilization
External conditions such as temperature have little impact on it
drug extraction
Extracted from animal milk
Engineering bacteria
meaning
Refers to microorganisms that use genetic engineering methods to efficiently express foreign genes.
gene expression
Drug proteins synthesized by bacteria may not be active
receptor cells
microbial cells
Target gene introduction method
Calcium ion treatment method
production conditions
Requires strict sterilization
Strictly control external conditions such as temperature, pH, and nutrient concentration required for engineering bacteria
drug extraction
Extracted from microbial cells or their culture fluid
specific areas
Agriculture and animal husbandry
Breeding resistant plants
Insect-resistant plants
Isolating genes with insect-resistant functions from certain organisms
disease resistant plants
Disease resistance genes derived from certain viruses, fungi, etc.
herbicide resistant plants
Genes that degrade or resist certain herbicides
Improved plant varieties
Introducing protein-coding genes rich in essential amino acids into plants can increase the content of this amino acid
Genes involved in plant anthocyanin metabolism were introduced into petunia, giving it color variations that are not found in nature, greatly improving its ornamental value.
Increase animal growth rate
Such as introducing exogenous growth hormone gene
Improve the quality of livestock products
By introducing the intestinal lactase gene into the cow genome, the lactose content in the milk secreted by the transgenic cows is greatly reduced, while other nutrients are not affected.
Medical and health fields
Produce drugs
Microorganisms and animal and plant cells
Genetically modify the cells of microorganisms or animals or plants so that they can produce drugs
Mammalian mass production of drugs
Scientists recombine regulatory files such as medicinal protein genes and promoters of genes specifically expressed in the mammary gland, and introduce them into fertilized mammalian eggs through microinjection to create a mammary gland bioreactor or breast bioreactor.
Create a transplant organ
Introducing certain regulatory factors into the genome of the organ donor to inhibit the expression of antigenic determinants or to try to remove the antigenic determinants
Combining cloning technology to create transgenic cloned organs that will not produce immune rejection reactions
food industry
Use genetically engineered bacteria to produce food, industrial enzymes, amino acids, vitamins, etc.
Scientists introduce the gene encoding bovine rennet into the genome of Escherichia coli, Aspergillus niger or yeast, and then mass-produce rennet through industrial fermentation
The amylase required for processing inversion syrup and the lipase used for processing baked goods can also be mass-produced by constructing genetically engineered bacteria and then using fermentation technology.
protein engineering
Overview
Base
Structural rules of protein molecules and their relationship with biological functions
means
genetic modification
Modify existing proteins
gene synthesis
Make new proteins
Purpose
Transform existing proteins or create a new protein to meet the needs of human production and life
process
Starting from the expected protein function
Design the expected protein structure
Presumed amino acid sequence
Find and change the corresponding deoxynucleotide sequence, or synthesize new genes
Get the protein you need
substance
Directed transformation or production of human needs resulting in
result
Produce proteins that do not exist in nature
status
application
medicine
principle
Using protein engineering to develop drugs
Example
If a cysteine on the interferon molecule is changed to serine, under certain conditions, the storage time can be extended
industry
principle
Protein engineering is widely used to improve enzyme activity or develop new industrial enzymes
Example
Subtilisin has the function of hydrolyzing proteins, so it is often used in the detergent industry, silk industry, etc.
agriculture
Scientists are trying to modify certain enzymes involved in regulating photosynthesis to improve the efficiency of plant photosynthesis and increase food production
Safety and ethical issues in biotechnology
Safety of genetically modified products
genetically modified results
microorganism
Reduce the production of diacetyl in beer yeast and shorten the fermentation cycle of beer
Construct high-yield and high-quality genetically engineered bacteria to produce amino acids
Producing drugs using genetically engineered bacteria
transgenic animals
Cultivate transgenic poultry and livestock that grow quickly and have excellent nutritional quality.
Breeding new animal varieties that are resistant to corresponding viruses
Establishing transgenic animal models of certain human diseases
transgenic plants
Breeding crops with new traits such as insect resistance, disease resistance, herbicide resistance and storage tolerance
Debate over the safety of genetically modified products
Reasons for debate
Different value orientations
country or society
policy
ideology
religious beliefs
The level of economic development
History background
Traditional Culture
ethics
content of argument
GM technology
Safety of genetically modified foods
Argument style
debate
Treat transgenic technology rationally
premise
Clear understanding of the principles and operating procedures of genetically modified technology
See that people's views are influenced by many complex political, economic and cultural factors
Rely on solid evidence and rigorous logic to think and debate
my country’s attitude towards genetically modified technology
Be bold in research and insist on independent innovation
Be cautious when promoting and ensure safety
Management must be strict and adhere to legal supervision
Relevant departments in our country have formulated a series of policies and regulations and established relevant institutions
Maintaining consumers’ right to know and choose about genetically modified products
Guarantee the safety of genetically modified technology and genetically modified products already on the market
Provide important technical support to ensure the safety of agricultural genetically modified organisms
clone
Clone classification
reproductive cloning
Purpose
Produce new individuals that can survive independently
level
individual level
debate
Agree
Scientific research has its own inherent law of development, and society should allow scientists to conduct research
People's current ethical and moral concepts cannot accept all this, but people's concepts can be changed.
majority against
Reproductive human cloning is contrary to human dignity
The artificial creation of people who are mentally and socially unsound seriously violates human ethics and morals, and is the proliferation of cloning technology.
Cloning technology is still immature and faces problems of miscarriage, stillbirth and deformed babies.
my country's attitude
Disapprove, do not allow, do not support, and do not accept any reproductive cloning experiments
therapeutic cloning
Purpose
Curing disease
level
cellular or tissue level
my country's attitude
The Chinese government attaches great importance to the ethical issues involved in therapeutic cloning and advocates effective monitoring and strict review of therapeutic cloning.
connect
All belong to asexual reproduction
Produce new individuals or new tissues with the same genetic information
IVF and Designer IVF
test tube baby
technical means
No genetic diagnosis required
Practical application
Solve the problem of infertility
Designer IVF
technical means
Genetic diagnosis required before embryo transfer
Practical application
Used to treat leukemia, anemia and other diseases
connect
in vitro fertilization
Early embryonic development in vitro
undergoing embryo transfer
All are sexual reproduction
Ban biological weapons
Judgment between conventional weapons and biological weapons
conventional weapons
Weapons other than weapons of mass destruction and destruction such as nuclear weapons and chemical weapons
basic means of conducting war
biological weapons
A collective term for weapons that use biological warfare agents to kill living creatures and destroy plants.
Types and Characteristics of Biological Weapons
type
Pathogenic bacteria
Bacillus anthracis
Yersinia pestis
Vibrio cholerae
Salmonella typhi
Shigella dysenteriae
Viruses
smallpox virus
zoopoxvirus
Biochemical poisons
botulinum toxin
Pathogenic bacteria that have undergone genetic recombination, etc.
Recombinant Bacillus cereus
Novel mousepox virus
Features
easy to get
Easy to prepare
Low cost
hard to find
Biological warfare agent aerosols are colorless and odorless, making them difficult to detect
If used secretly at night or in foggy weather, it will be more difficult to detect in time.
Many ways of transmission
breathe
diet
skin contact
insect bites
Pathogenic, highly contagious
Once a case occurs, it is easy to spread quickly among the crowd, causing casualties and even causing social panic.
Widespread pollution
Modern biological weapons can disperse biological warfare agents into aerosols, which can cause large-scale contamination
Greatly affected by natural conditions
temperature
terrain
wind direction
biological specificity
Biological weapons can infect people and livestock and can be life-threatening
Do not destroy inanimate objects
Weaponry
building
There is an incubation period
Under appropriate conditions, some pathogenic microorganisms can survive for a considerable period of time
Bacillus anthracis spores can survive for ten years in dark, moist soil
Difficult to treat
Biological Weapons Convention
April 1972
The Soviet Union, the United States, and the United Kingdom signed the Biological Weapons Convention in their capitals respectively, and it came into effect in March 1975.
November 1984
Our country has also joined this convention
June 1998
The heads of state of China and the United States reiterated that they will not develop, produce, or stockpile biological weapons under any circumstances, and oppose the proliferation of biological weapons and their technology and equipment.
year 2010
At the 65th United Nations General Assembly, our government advocated the complete prohibition and thorough destruction of biological weapons and other types of weapons of mass destruction