Genetics and immunology of Microbes

Microbial genetics is concerned with the transmission of hereditary characters in microorganisms. It plays a unique role in developing the fields of molecular and cell biology. It has also found applications in medical, agricultural, food and pharmaceutical industries. Microbes are ideally suited for combined biochemical and genetic studies, and proved to be successful in providing information on genetic codes and gene regulations. After the discovery of DNA transfer, bacteria were of great interest because of their higher rate of reproduction and mutation than other larger organisms. Conjugation, transformation, and transduction are the important methods for mapping the genes on bacterial chromosomes. Recombinant DNA technology, selection, mutation, reproductive cloning, and use of plasmids form a part of genetic engineering tools. Metagenomics is the study of genetic material derived from environmental samples. Microbial genomics can be used to create new biofuels. Pathogenicity islands are discrete genetic loci that encode more virulent factors. 

Immunology is the study of protection from invading organisms like viruses, bacteria, protozoa, parasites and our responses to them. The commensal microbiota plays a significant role in modulating the outcome of immune responses in the host body keeping immune homeostasis in health. The barrier tissue such as the skin stops the entry of organism into our bodies. However, if the organisms penetrate through the skin, then macrophages and neutrophils kill them without the need for antibodies. Immediate challenge comes from soluble molecules that deprive the invading organism of essential nutrients and from certain molecules that are found on the surfaces of epithelia, in secretions and in the blood stream. A second line of defence is the adaptive immune system which takes days to respond to a primary invasion. Here, we see the production of antibodies and the cells involved include B-cells and T-cells. Development of autoimmune diseases is a multi-factorial process. Triggers from environmental and genetic factors as well as pathogenic pathways might explain the causes and outcomes of diseases in humans.