Recombination of genes

Kindt, T.J. Mandy, W.J. (1972). Recombination of genes coding for constant and variable regions of immunoglobulin heavy chains. J. Immunol. 108, 1110-1113. 

Mycelia are in principle stuck in one place and cannot move to another place very quickly. Thus they have means to escape if the conditions should get unfavorable for growth. There are two ways of escaping, either in time or in space, and fungi form special structures called spores to do this. Spores can be either asexually formed after mitosis or sexually formed where meiosis with recombination of genes is involved in the process of spore formation (Fig 1.15-18). If the asexual spores are formed singly and directly from hyphal branches the spores are called conidia. 

The methods involved in the production of proteins in microbes are those of gene expression. Several plasmids for expression of proteins having affinity tails at the C- or N-terminus of the protein have been developed. These tails are usefiil in the isolation of recombinant proteins. Most of these vectors are commercially available along with the reagents that are necessary for protein purification. A majority of recombinant proteins that have been attempted have been produced in E. Coli (1). In most cases these recombinant proteins formed aggregates resulting in the formation of inclusion bodies. These inclusion bodies must be denatured and refolded to obtain active protein, and the affinity tails are usefiil in the purification of the protein. Some of the methods described herein involve identification of functional domains in proteins (see also Protein engineering). 

Bacteria can develop resistance to antimicrobial agents as a result of mutational changes in the chromosome or via the acquisition of genetic material (resistance genes carried on plasmids or transposons or the recombination of foreign DNA into the chromosome) (Fig. 2). 

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