The process by which genetic material (DNA) is transferred from one bacterium to another bacterium through a virus to create a new bacterium with new characteristics is called transduction. In 1952, scientists Zinder and Lenderberg discovered bacterial transduction.
Transformation of bacteria
The process by which the DNA of one cell enters another cell causing genetic rearrangement is called transformation. In the transformation process, only DNA from the donor cell enters the recipient cell. Then the DNA of the donor and the recipient combine to cause genetic recombination.
Conjugation of bacteria
The process by which nuclear material (DNA) is transferred from one cell to another cell by forming a conjugation channel between two cells is called conjugation. Two bacterial cells of opposite sex (+,Ñ) come close to each other and lie closely side by side. One of them is called Donor and the other Recipient. The walls of two facing cells swell to form the synovial duct. The two ducts grow and touch each other. Later the wall of the contact area melts to form a conjugation canal. Nuclear material (DNA) from the donor cell enters the recipient cell through the pilus. Before the entire nuclear material enters the recipient cell from the donor cell, the two cells separate from each other. As a result, part of the nuclear material enters the recipient cell from the donor cell. The donor cell is destroyed by loss of nuclear material. Later the nuclear material of the donor and recipient fuse to form a zygote. It is called merozygote. Later the merozygote continues to increase in number in the process of bifurcation. Each new cell produced contains donor and acceptor properties. In 1946 scientists Lenderberg and Tatum discovered the conjugation process in bacteria.
Sexual reproduction of bacteria
True sexual reproduction does not occur in bacteria. Its sexual reproduction is known as genetic recombination. The process in which the genetic material or DNA of a cell is transferred to another cell to create a new cell with new characteristics is called genetic recombination. In 1946 scientists Lenderberg and Tatum discovered sexual reproduction in bacteria. Wollman Rink and Jacob described the sexual reproduction of bacteria. Genetic recombination in bacteria occurs in three ways.
1. Conjugation: The process by which nuclear material (DNA) is transferred from one cell to another cell by forming a conjugation channel between two cells is called conjugation. Two bacterial cells of opposite sex (+,Ñ) come close to each other and lie closely side by side. One of them is called Donor and the other Recipient. The walls of two facing cells swell to form the synovial duct. The two ducts grow and touch each other. Later the wall of the contact area melts to form a conjugation canal. Nuclear material (DNA) from the donor cell enters the recipient cell through the pilus. Before the entire nuclear material enters the recipient cell from the donor cell, the two cells separate from each other. As a result, part of the nuclear material enters the recipient cell from the donor cell. The donor cell is destroyed by loss of nuclear material. Later the nuclear material of the donor and recipient fuse to form a zygote. It is called merozygote. Later the merozygote continues to increase in number in the process of bifurcation. Each new cell produced contains donor and acceptor properties. In 1946 scientists Lenderberg and Tatum discovered the conjugation process in bacteria.
2. Transformation: The process by which the DNA of one cell enters another cell causing genetic rearrangement is called transformation. In the transformation process, only DNA from the donor cell enters the recipient cell. Then the DNA of the donor and the recipient combine to cause genetic recombination.
3. Transduction: The process by which genetic material (DNA) is transferred from one bacterium to another bacterium through a virus to create a new bacterium with new characteristics is called transduction. In 1952, scientists Zinder and Lenderberg discovered bacterial transduction.
Microcyst of bacteria
Several cells of myxobacteria unite to form a swarm. Each cell of the swarm becomes a microcyst. New bacteria are born from microcysts. For example – Myxococcus fulvus, Chondromyces crocatus.
Endospore of bacteria
Bacterial protoplast shrinks and becomes spherical or ovoid due to lack of food in unfavorable environment. It is then enveloped by a thick coat and becomes an endospore. This is called a resting spore. New bacteria are born from resting spores under favorable conditions. For example, Bacillus subtilis, Clostridium tetanus, Escherichia coli.
Zoospores of bacteria
Bacteria produce zoospores in unfavorable environment. Zoospores produce new bacteria. Such as Azotobactor, Rhizobium.
Gonidia of bacteria
protoplasts of protoplasts of protozoan bacteria divide to form smaller parts in unfavorable environment. Cytoplasm accumulates around each segment to form gonidia. New bacteria are formed from the transformed gonidia. For example, Leucothris.
Conidia of bacteria
Conidiophores are formed from protozoan bacteria. Conidiophores produce tiny conidia. The conidia are arranged like chains. The mature conidia detach and germinate in a favorable environment to form new bacteria. For example, Streptomyces.
Asexual reproduction of bacteria
1. Conidia: Conidiophores are formed from protozoan bacteria. Conidiophores produce tiny conidia. The conidia are arranged like chains. The mature conidia detach and germinate in a favorable environment to form new bacteria. For example, Streptomyces.
2. Gonidia: protoplasts of protoplasts of protozoan bacteria divide to form smaller parts in unfavorable environment. Cytoplasm accumulates around each segment to form gonidia. New bacteria are formed from the transformed gonidia. For example, Leucothris.
3. Zoospores: Bacteria produce zoospores in unfavorable environment. Zoospores produce new bacteria. Such as Azotobactor, Rhizobium.
4. Endospore: Bacterial protoplast shrinks and becomes spherical or ovoid due to lack of food in unfavorable environment. It is then enveloped by a thick coat and becomes an endospore. This is called a resting spore. New bacteria are born from resting spores under favorable conditions. For example, Bacillus subtilis, Clostridium tetanus, Escherichia coli.
5. Microcyst: Several cells of myxobacteria unite to form a swarm. Each cell of the swarm becomes a microcyst. New bacteria are born from microcysts. For example – Myxococcus fulvus, Chondromyces crocatus.