Strain Improvement/ Development
Strain development
spectrum for microbial isolation, Identification of Industrially isolated
microbes & different approaches for improvement of industrial important
strains
Strain is a genetic variant of a microbe, plant, and rodents. A strain is a group of species with one or more characteristics that distinguish it from other sub groups of the same species of strain. Each strain is defined by a name, number or letter.
The strain development or strain improvement is a key factor in the development of an antibiotic as a potential therapeutic agent.
It is meant for obtaining microbial isolates possessing certain desirable characteristics for solving a specific problem
It involves mutation and selection of mutants.
For strain improvement first we should have to isolate the microorganism, identification of isolated microbe, mutagenesis of the population to create genetic variants, random selection or screening from the surviving population to find the improved strain and then identification of that improved strain. The isolation and identification is used in microbial biosensor, bio pesticides and is used to improve the industrial production.
The site for isolation of microbes is decided by the type of microbes one is interested in. Two strategies are following for the isolation of microbes:
After the isolation, it is important to identify the specific microbe and the identification is done wih the help of following characteristics:
(i.e. shape, length, width, body arrangement, motility, capsule and spores)
(MacConkeys agar, differential media, characteristic media and enrichment media)
(Methyl Red Test MR-Test, Voges-Prokauer Test VP-Test)
(Staining is takes place to visualize the microbial interior or exterior part)
Mutagenesis is a process by which the genetic information of an organism is changed, resulting in a mutation. It may occur spontaneously in nature or as a result of exposure to mutagens.
It is also called the natural mutation because arises naturally not from any mutagens.
A mutation that is produced by treatment with a physical or chemical agent, which affects the DNA molecules of a living organism.
Direct mutation was a hypothesis proposing that organisms can respond to environmental stress by orthogenetic ally directing mutations to certain genes or areas of genome. By addition, substitution, deletion or point mutation.
Figure 1 Direct Mutation (Point Mutation, insertion)
Screening is done by two methods either by random screening or rational screening.
When the mutation is induced, strains are picked from the population randomly and then tested whether the metabolites are formed are not.
Rational screening needs to understand the metabolism of product and regulation of pathways that gives the information of metabolic check points. It also suggests the ways how to isolate mutants with specific traits.
Empirical strain improvement is done according to scientific calculations, to find or to develop. It is a largely empirical activity because the specific biochemical and genetic mechanism involved are only poorly understood. Once a new metabolite has been discovered, a campaign of Empirical strain improvement is undertaken to boost the level of product to a titre, at which the process becomes economically viable while semi empirical strain improvement is carried out in the light of results from scientific research and the aim of semi empirical strain improvement is to reduce the computational time drastically.
Strain
Strain is a genetic variant of a microbe, plant, and rodents. A strain is a group of species with one or more characteristics that distinguish it from other sub groups of the same species of strain. Each strain is defined by a name, number or letter.
Examples:
1. Flu strain of Influenza virus
2. Shiga toxin producing E.coli (STEC-O157-:H7)
3. Klebseilla pneumonia MGH 78578
4. Klebseilla variicola strain (k. variicola
At-22)
Strain Improvement or Strain Development:
The strain development or strain improvement is a key factor in the development of an antibiotic as a potential therapeutic agent.
Strain Improvement:
It is meant for obtaining microbial isolates possessing certain desirable characteristics for solving a specific problem
Strain development:
It involves mutation and selection of mutants.
How the strain improvement is done?
For strain improvement first we should have to isolate the microorganism, identification of isolated microbe, mutagenesis of the population to create genetic variants, random selection or screening from the surviving population to find the improved strain and then identification of that improved strain. The isolation and identification is used in microbial biosensor, bio pesticides and is used to improve the industrial production.
Isolation of microbes:
The site for isolation of microbes is decided by the type of microbes one is interested in. Two strategies are following for the isolation of microbes:
1. To collect the free living microbes from our
environment
2. To collect the microbes from specific sites
among natural micro flora with desired characteristics
Identification of Industrially important microbes:
After the isolation, it is important to identify the specific microbe and the identification is done wih the help of following characteristics:
1) Morphology
(i.e. shape, length, width, body arrangement, motility, capsule and spores)
2) Selective and diagnostic media
(MacConkeys agar, differential media, characteristic media and enrichment media)
3) Biochemical tests
(Methyl Red Test MR-Test, Voges-Prokauer Test VP-Test)
4) Profile of microbial strains
(Staining is takes place to visualize the microbial interior or exterior part)
5) Rapid identification methods(SEM, TEM)
6) Cultural characteristics(Shape, size,
elevation margins, colour, and structure)
Approaches for strain improvement:
1. Mutagenesis
2. Selection or Screening
3. Empirical strain improvement and Semi
empirical strain improvement
Mutagenesis:
Mutagenesis is a process by which the genetic information of an organism is changed, resulting in a mutation. It may occur spontaneously in nature or as a result of exposure to mutagens.
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Types of Mutation
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1. Spontaneous Mutation
2. Induced Mutation
3. Direct Mutation
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Table 1 Types of Mutation
Spontaneous Mutation:
It is also called the natural mutation because arises naturally not from any mutagens.
Induced Mutation:
A mutation that is produced by treatment with a physical or chemical agent, which affects the DNA molecules of a living organism.
Direct Mutation:
Direct mutation was a hypothesis proposing that organisms can respond to environmental stress by orthogenetic ally directing mutations to certain genes or areas of genome. By addition, substitution, deletion or point mutation.
Figure 1 Direct Mutation (Point Mutation, insertion)
Selection or screening:
Screening is done by two methods either by random screening or rational screening.
Random Screening:
When the mutation is induced, strains are picked from the population randomly and then tested whether the metabolites are formed are not.
Rational Screening:
Rational screening needs to understand the metabolism of product and regulation of pathways that gives the information of metabolic check points. It also suggests the ways how to isolate mutants with specific traits.
Empirical and Semi- empirical strain improvement:
Empirical strain improvement is done according to scientific calculations, to find or to develop. It is a largely empirical activity because the specific biochemical and genetic mechanism involved are only poorly understood. Once a new metabolite has been discovered, a campaign of Empirical strain improvement is undertaken to boost the level of product to a titre, at which the process becomes economically viable while semi empirical strain improvement is carried out in the light of results from scientific research and the aim of semi empirical strain improvement is to reduce the computational time drastically.
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