Antenatal diagnose: Over 2500 genetic defects are known in human being due to certain defects in genes and the individuals carrying such defects are not normal . Their proper diagnosis at embryonal level is thus desirable using amniotic fluid which contain fetal DNA. It is called Antenatal diagnosis.
Antisense transcription : synthesis of m-RNA occurs on sense strand of DNA. If is occurs on complementary strand of sense strand, it is called antisense transcription .Some rare horticultural plants have been developed through this technique carrying unique characters not found elsewhere.
Annealing - The process of denaturing ds-DNA by heat treatment and then slow cooling to allow the formation of DNA-RNA hybrid using desired RNA.c- DNA library - Complementary -DNA library produced by using template of m-RNA synthesizing various types of c- DNA of a genome.
Biolipistics: A type of red dye synthesized by biotechnology and named as Shikonin. It is a naphthoquinone and it is produced on mass scale for commercial use in cosmetics using cell culture of Lithospermum erythrorhizon.
Blotting technique: Transfer of macromolecules (usually DNA fragments) by capillary action from a gel plate to a nylon membrane (-a type similiar to zeroxing of printed sheet.)
Southern Blotting Technique (discovered by E.M southern) is used in DNA-RNA hybridization . Transfer of DNA strands ( fragments) after gel electrophoresis is done using nitrocellulose filter to facilitate further processing when needed. It is used mainly in DNA finger printing technique. Northern Blotting TEchnique is applied for separation and transfer of RNA fragments from agrosol gel to nylon mesh. It is infact reversal of southern Blotting. In Western Blotting Technique analysis of protein is done. Protein fragments are electrophoresed in polyacrylamide gel and then transferred on to nitrocellulose nylon membrane and the protein bonds are detected by using interaction with antibodies.
Callus: undifferentiated mass of cells produced in tissue culture experiment or in protoplast culture. Transgenic plants (genetically modified plants) can also developed using callus developed by the cells carrying recombinant DNA.
Chimera: A cell having genetically different DNA strands, developed due to addition of foreign gene into plasmid DNA to construct recombinant DNA.
Chimeric DNA: Hybrid DNA such as r-DNA, cosmid DNA, plasmid DNA, etc. r-DNA is produced by combination of vector DNA and desired gene. Cosmid DNA is produced by hybridization of plasmid DNA with a piece of lambda phage DNA including its cos-site. Phasmid DNA is produced by hybridization of lambda phage DNA with plasmid DNA where att-site of phage DNA is included.
Plasmid DNA +Foreign gene= r-DNA.
Cos-site containing phage DNA + Plasmid DNA= Plasmid
Clones : A group of genetically identical cells or organisms asexually descendant from a common ancestor (identical copies). all the cells or organisms of a clone have same genetic set up and they are thus representing the exact copies of the original.
cloning vectors: self replicating entity to which the foreign DNA is covalently attached for purpose of replication in host cell.
Cloning organisms: A host cell which can easily accept the donor gene. It contains its own genes and inserted genes and allowing them to replicate in usual manner. Common cloning organisms used in biotechnology is E.coli.
Gene Therapy: Replacement of abnormal genes with normal genes through r-DNA technology . The first trial of actual (clinical) gene therapy was conducted in 1990 in U.S.A . A four years old girl suffering with ADA (Adenosine Deaminase Deficiency) a lethal disorder was transfected with lymphocytes bearing the ADA gene carried by retroviral vector.
Monoclonal antibodies: Homogeneous immunization reagent synthesized technology for producing vaccines and for diagnosis of blood group and many genetic diseases.
Nif-genes: Nitrogen fixing genes, represented by a cluster of 17 genes and found in the cells of nitrogen fixing bacteria or in some cyanobacteria(e.g. Rhizobium, Klebsiella, Nostoc, Anabaema, etc. nif-genes are used in plant biotechnology .
pBR -322- It is constructed from recombination of two plasmid DNA (PBR- 318 and PBR-320). It consists ORI- site (site for origin of replication), R-site (gene for resistance against ampicillin and tetramycin ) and unique site about twenty types of restriction enzymes. It is thus a chimeric plasmid DNA. It is one of the standard cloning vectors widely used in gene cloning experiments (derived from E.coli. plasmid CoIE1), which is 4,362 bp DNA and was derived by several alterations in earlier cloning vectors. pBR-322 was named after Bolivar and Rodriguez, Mexican postdoctoral researchers who constructed it in 1977 in the laboratory of Herbert Boyer at the University of California San Francisco. It has genes for resistance against two antibodies tetracycline and ampicillin.
PCR technique (Polymerase chain reaction technique): A technique used for amplification of gene or DNA molecules .DNA strands are first denatured and then the two strands get separated to synthesize their complementary strands in presence of DNA polymerase enzyme using dATP, dCTP, dGTP and dTTP nucleotides as raw materials. This process is repeated several times to obtained desired amount of DNA for further processing. PCR is discovered by Kary Mullis in 1985 and is carried out in vitro. It mainly requires (a) the desired gene or segment of DNA to be amplified (b) nucleotide primers each about 20 bases long, (c) monomers of DNA as deoxynucleoside triphosphates such as dATP, dCTP, dGTP and dTTP. (d) heat stable DNA polymerase, viz., Tag polymerase(obtained from a bacterium,(Thermus aquaticus), pfu polymerase (obtained from a bacterium , (Pyrococcus furiosus) and vent polymerase (obtained from bacterium Thermococcus litoralis). pfu and vent Polymerases are found to be more efficient as compared to Taq polymerase.All these polymerase are obtained from thermophilic bacteria .All these polymerase ar obtained from thermophilic bacteria and they are capable of showing their activities at a very high temp. like 75 degree to 80 degree C.
DNA is denatured at about 90 to 95 degree C. and then these 3 types of polymerases are used for amplification process. One DNA strand is capable of producing million of their identical copies through PCR technique .
Plasmids : Extra- nuclear genetic material found in most of the bacterial cells as double stranded circular rings in addition to chromosomal DNA. They have proved to be the best vector for carrying desired gene/s for recombinant DNA technology. Plasmids can be easily taken out from the bacterial cells through diffusion by increasing the permeability of bacterial membrane and cell wall and can be reinserted (after constructing recombinant DNA ) into the bacterial cell for cloning.
Ri Plasmids: A plasmids of agrobacterium rhizogenes which induces quick rooting in host organisms after infection.
Ti Plasmids: Plasmids of Agrobacterium tumefaciens, capable ofproducing tumour in infected host cells through synthesizing cytokinin like growth hormone.
Somaclonal variations : Variations generated in somatic cells or tissues during prolonged storage in culture medium due to spontaneous mutation or due to action of chemicals used as ingredient of culture medium or due to change in position of transpozons.
Super bag: A genetically engineered variety of Pseudomonas putida carrying plasmids to hydrolyse xylane, nephthalene, camphor or toluene like hydrocarbons found in crude petroleum. It was first created by Dr. Anand mohan Chakrabarthy to deal with the problem of oil leakage from oil tankers in oceans .
Terminator technology : A technology used in producing plants of genetically modified high yeilding varieties developed recombinant DNA technology where seeds do not develop viable embryo and thus remain unable to germinate and produce seedlings.
Transduction : Phage mediated transfer of genetic material from one bacterium to the other (as was first reported in Salmonella bacterium by Zinder and Lederberg).
Caulimo-virus or cauliflower Mosaic Virus (CaMV) is also used as a vector in plant biotechnology . It has double stranded and linear DNA of nearly 8 kb length. It causes diseases in wide range of dicot plants. Its replication involves reverse transcriptase enzymes similar to vetro-viruses .
Cybrids: A virus hybrids produced by somatic hybridization using protoplasts of two different parents. They carry cytoplasmic genes of both the parents but genome of only one parent.
Coliphage : A virus parasitizing on coliform bacteria or E.coli (e.g, )bacteriophage which posseses single stranded and circular DNA
Cybridization : Technique of producing cybrids by protocol plasmic fusion using Poly Ethylene Glycol (PEG) or electrofusion .
DNA finger printing : A technique in which DNA is cut into fragments of varying sizes using restriction enzyme and then fragments are separated through gel-electrophoresis (DNA) fragments carry negative charges and thus they move towards the positive pole through the medium of suitable electrolyte. DNA fragments are then transferred to nylon membrane using. Southern blotting technique. Using radioactive DNA probe (synthetic DNA strands carrying radioactive bases), their presence is recorded on X-ray plate through autoradiography . These bands represent DNA fingerprints . This technique is used I forensic science for solving complicated cases of murders and rapes (in absence of eye witness ) in or solving disputes in parentage .
DNA probe :Synthetic radioactive fragments of DNA used in locating the position of specific DNA fragments obtaining during DNA profiling of DNA fingerprinting after electrophoresis and southern blotting.
Electrophoresis : A technique of separating DNA fragments of gel plate under the influence of electric current through the medium of suitable electrolyte.
Engineered bacterium: A bacterium carrying desired foreign gene/s for obtaining specific products or for introducing desired gene/s into organisms for producing genetically modified organism of desired nature.
Foreign DNA :DNA used for contracting recombinant DNA using suitable vector DNA or vehicle DNA. Foreign genes are also called passenger DNA and vector DNA is called vehicle DNA.
Gene back : Collection of genes of a genome with their correct identity for future use in recombinant DNA technology or in formation of desired transgenic organism.
Gene Counseling: Gene counseling is done after knowing the correct family history and genetic diseases. If any in the family to work out possibility of future pregnancy on the basis of antenatal diagnosis .
Gene splicing : Cutting and rejoining the DNA sequence for r-DNA technology.
ELISA (Enzyme linked Immunosorbent Assay) Test: Used in case of detecting AIDS. It is useful in estimating the amount of specific antibody present in the antiserum used for the reaction.
Hybridomas: A hybrid of B-lymphocyte cell and myeloma cell (bone cancer cell) produced by somatic hybridization technique to synthesize desired Monoclonal Antibodies (MAB).
In vitro studies: Study outside the living body, i.e. by culturing the organisms in artificial medium or synthetic medium( as in case of tissue culture, organ culture, etc.)
In Vivo studies: Study within the living system or living body as in case of study of microsporogenesis in anthers, megaporogenesis in developing ovules or embryogenesis in fertilized ovules.
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