In this article, I briefly describe costimulatory receptors CD28 and ICOS and how they bind with their ligands. Costimulatory receptors Co-stimulatory signals are required for optimal T-cell activation. T-cell non-responsiveness arises from high affinity TCR-MHC interactions in the absence of functional antigen presenting cells (APCs). It is called T cell anergy. The interaction between specific … Read more >>
In this article, I briefly describe the duplication of retrovirus in a host cell. The enveloped virus-Retrovirus These are enveloped viruses, that belong to the family Retroviridae. A retrovirus is an RNA virus duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. When the virus infects a … Read more >>
In this article, I briefly describe the various methods of DNA sequencing and their applications. DNA sequencing The process of determining the order of nucleotides in DNA is called DNA sequencing. It determines the order of the four bases, i.e., adenine, guanine, thymine, and cytosine. The nucleotide sequence is the base of knowing a gene … Read more >>
In this article, I briefly describe how desiccation, filtration, osmotic pressure, and radiation control microorganisms. Physical methods of microbial control It is necessary to control microorganisms for the prevention of diseases. Microbial growth is controlled either by killing microorganisms or by inhibiting the growth of microorganisms. Microorganisms are generally controlled by the use of physical … Read more >>
In this article, I briefly describe how temperature controls the growth of microorganisms. Microbial control Microorganisms are controlled to prevent transmission of disease and infection. Microbial growth is controlled either by killing microorganisms or by inhibiting the growth of microorganisms. Microbes must be controlled to avoid contamination by their undesirable growth and prevent material deterioration … Read more >>
In this article, I briefly describe restriction enzymes, their recognition sequences, and the frequency of recognition sequences. What are restriction enzymes? The enzyme that cleaves DNA at specific recognition sites, is called a restriction enzyme. These belong to the endonuclease group of enzymes. Identifying and manipulating restriction endonucleases in the 1960s and early 1970s made … Read more >>
In this article, I briefly describe the preparation of plasmid DNA. Plasmid DNA A plasmid is a small, circular, extrachromosomal DNA molecule in bacteria, which replicates independently. Chromosomes contain all the essential genetic information, whereas plasmids carry some additional genes, which aid in the survival of the organism. Plasmids provide some selective advantages such as … Read more >>
In this article, I briefly describe the preparation and purification of total cell DNA. Total DNA and its preparation The complete set of genetic information is the genome of an organism. The genome is stored in long molecules of DNA, called chromosomes. Total cell DNA acts as a source for the genes to be cloned. … Read more >>
In this article, I briefly describe animal viruses and their use as cloning vectors. Cloning vectors A small piece of DNA into which a foreign DNA fragment is inserted is known as a cloning vector. The cloning vector may be the plasmid from a bacterium, a higher organism’s cell, or DNA taken from a virus. … Read more >>
In this article, I briefly describe cloning vectors for higher plants. Cloning vectors A small piece of DNA into which a foreign DNA fragment is inserted for cloning purposes is known as a cloning vector. The cloning vector may be the plasmid from a bacterium, a higher organism’s cell, or DNA taken from a virus. … Read more >>