PI3K Pathway

Phosphoinositide 3-Kinase enzyme It is a signal transduction system that connects oncogenes and multiple receptor classes to many cellular functions such as cell survival, proliferation and differentiation. The key enzyme family in this pathway is PI3Ks (Phosphoinositide 3-Kinases) which transducer signals from various growth factors and cytokines into intracellular messages by generating phospholipids. These phospholipids activate the serine- threonine...

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Phage Vector

Bacteriophages 1) Viruses specifically infect bacteria. 2) Phages have simple structure: Genetic material (DNA or RNA) is encapsulated in a protective  proteineous coat called caspid. 3) It replicates within the bacteria and lysis them. Bacteriophage λ in Gene cloning * It’s an E.Coli virus that can carry an insert of a range between 15-20 kb * After Bacteriophage λ infects the E.Coli, two things may happen:...

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Ultraviolet Mutagenesis

Ultraviolet light (UV) UV light, an electromagnetic radiation with a wavelength range between 400 nm to 10 nm, i.e. shorter and longer than visible light and X-ray. Natural source of UV light is sun and its artificial emitted by electric arcs or by mercury lamps. It has a strong genotoxic effects to produce DNA damage, induce mutations and causes tumor development. It also said to be the main cause of skin cancer. Purines and pyrimidine absorbs UV at 260 nm wavelength, which makes a perfect source for identifying nucleic acids...

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Cloning Vector : Vehicle for transport foreign DNA into Host cell.

A DNA molecule that can carry inserted DNA and can be perpetuated in host cell is called cloning vector. A Vector for cloning should a) have origin of replication which makes them replicate inside an appropriate host, even though a foreign DNA is present.   b) have a site for inserting the target gene. c) have restriction enzyme site for cutting and inserting the target gene. d) have a selectable marker for identify the cloning containing the targeting gene. e) be small with an ideal size of less than 10 kb. (large size tends...

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Ti plasmid as vector for plants

It is circular and not always It’s contains 56%GC content out of which 81% encodes for a protein. It has various types of opines Octopine Nopaline Succinamopine Leucinopine It is found in Agrobacterium tumefacien and Agrobacterium rhizogenes. There is no pseudogene. It works only in dicotyledon plants. The Ti plasmid is lost when Agrobacterium is grown above 28°C. Such cured bacteria do not induce crown galls, i.e. they become avirulent. Genes in the virulence region are grouped into the operons vir...

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Plasmid

1) Self- replicating, double stranded, circular DNA molecule. 2) It’s maintained as an independent extrachromosomal entity in bacteria. 3) There are different types of plasmid that has been present in certain for survival and diversification: F plasmid à Involves in conjugation for transferring information to another bacteria.  * Its total length may be 100 kb.* It contains genes responsible for cell attachment and plasmid transfer...

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cDNA Library - A detailed note

Its a collection of  cDNA (Complementary DNA) clones generated from mRNA sequences of  a single cell population. cDNA is double stranded DNA complementary to the mRNA sequence synthesized by the enzymes reverse transcriptase and DNA polymerase.  Steps involved in creating cDNA library:  Extraction and purification of mRNA from the cell CLICK HERE TO READ Synthesis of cDNA from the total mRNA CLICK HERE TO READ cDNA cloning CLICK HERE TO READ Screening of  the host containing the cDNA  CLICK...

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Genomic Library- A detailed note

It is the collection of total genomic DNA from a single organism. The total genome from an organism is taken and digested into fragments. Then, they are carried into a host organism by a vector DNA and cloned into many copies. Through screening process, the cloned host organism with the gene of interest is taken and preserved for future use. So, now we will discuss the steps in constructing a genomic library. 1) Isolation and purification...

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Endocytosis: Import system of the cell

Endocytosis is the import system of the cell where the macromolecules and particles from the surrounding medium is taken inside the cell. Cells internalize the materials by using plasma membrane components and deliver them to an internal compartment called endosomes.  From this endosomes they can be recycled to same or different regions of the plasma membrane or can be delivered to lysosomes for degradation. There are three types of endosomes in the cell, Early endosomes Endosomes which are found just beneath the plasma membrane...

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