Tag: applications of biotechnology

The conventional methods which are commonly used for the removal of nickel from water are physico-chemical methods, such as chemical coagulation, chemical oxidation or reduction, active carbon adsorption, filtration, ion exchange and membrane technologies. Nickel behaves the same as iron, and can be removed by a strong acid cation exchanger. Activated-carbon filtration can be used to reduce the amount of nickel in drinking water, but may not remove it all. Reverse osmosis will remove 97 - 98% of the nickel from drinking water.

• Sir Ian Wilmut, (born July 7, 1944, Hampton Lucy, Warwickshire, Eng.), British developmental biologist who was the first to use the nuclear transfer of differentiated adult cells to generate a mammalian clone, a Finn Dorset sheep named Dolly.
  
• It was a female domestic sheep, and the first mammal cloned from an adult somatic cell, using the process of nuclear transfer.
• Hence Clone Dolly was produced by the attempts of Ian Wilmut.
• So, the correct answer is 'Ian Wilmut'.

Cybrids are artificial hybrid cell produced by inserting nuclear material from one organism into an enucleated cell. Clones are the population of genetically identical individuals which are produced by asexual or vegetative reproduction. Hybrids are the recombinant individuals, that have genes from both parents and thus, show new combination of traits. Sexual reproduction does not produce clones owing to the three processes that causes recombination of genetic material and produce variations in progeny. These three processes are cross over during meiosis, independent assortment of chromosomes during meiosis and random fusion of gametes. The resultant progeny will be a hybrid. Asexual reproduction does not include meiosis and fusion of gametes; omits the variation creating processes and produce clones. 

B) A population of genetically identical individuals, obtained from asexual reproduction is a clone because fusion of gametes does not take place in vegetative propagation so there is no chance of recombination and variation. The parent cell divides to form daughter cell by mitosis due to which the offspring are genetically identical to the parent. The offspring produced are clones of their parent and have the same number of chromosomes.

Clone formation is due to asexual reproduction. As meiosis does not occur here, so no gamete formation, hence no fusion of gametes occurs in clone formation.

• Salmonella (S.) typhi is an important intracellular pathogen, exclusively for humans  that causes typhoid or enteric fever that make most suitable as a vaccine vector carrying antigens of other pathogens. The hybrids are studied for  induced immune response against response to both the Salmonella bacteria and the antigen of the pathogen in under study.
• Retroviral vectors are created by replacing retroviral gag, pol, and env genes with therapeutic gene and used in gene therapy which is the process of introduction of DNA into living human beings in order to treat disease. It is used to replace a missing gene product or to correct mutant alleles.
• Baculoviruses have rod-shaped capsids and large, double-stranded DNA genomes that infect insects. Their polyhedrin gene is replaced with foreign DNA which is expressed at high levels under the control of the endogenous polyhedrin promoter and is mainly used for high-level transient protein expression in insects and insect cells.
•  Rhizopus nigricans is used as host vector system for mass synthesis of protein encoded by gene cloned in plasmid vectors.
  
• So, the correct answer is 'Retrovirus'.