Cellular cloning

Significant efforts are necessary to turn the var ious techniques of generating transgenic animals into a routine method. 

Die automated sorting of living transgenic embryos, demonstrated with Drosophila mutants, facilitates resear ch in generating and characterizing transgenics. °°  

One of the techniques used is piezo-actirated microinjection, whereby a vibrating needle pierces the donor cell and oocyte plasma membrane. Tliis technique was used to directly inject porcine fetal fibroblast donor nuclei into enucleated oocytes. The injection was followed by activation by means of an elechic pulse after nuclear hansfer by microinjec-tion. 

Another metliod involves the fusion of porcine gi anulosa-derived donor cells witli enucleated mature oocytes. After 18 h, the donor nucleus is removed from tire fust oocyte and transfened to the cytoplasm of a fertilized egg. Tliis double nuclear hansfer strategy was used to overcome tire putatively insufficient activation stimulus provided after nuclear hansfer in the prior one-step method. 

Stem cells, one source of cloning tissues and organs, hold a promise for conhibuting to a vast aiiay of ailments, since they have tlie potential to produce various cell types and 

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There are many functions of protonema it represents an organ of biosynthesis, substrate exploitation, absorption and solute transport and lastly of new shoot production. Whether it is produced during a sexual or vegetative cycle, it is a cellular clone that vegetatively multiply the number of new gametophores. 

To overcome the large variability in the starting material and the rapid senescence observed after passages of pure cerebromicrovascular endothelial cells from primary cultures, Roux et al. (1994) produced an immortalized cellular clone displaying a stable, non-transformed phenotype. The aim was to constitute a valuable in vitro model of the rat blood-brain barrier... 

Ceballos-Picot, I., Nicole, A., and 8inet, P. M., 1992, Cellular clones and transgenic mice overexpressing copper-zinc superoxide dismutase Models for the study of free radical metabolism and aging, in Free Radicals and Aging (I. Emerit and B. chance, eds.), pp. 89-98, Birkhauser, Basel, 8witzer-land. 

Khew-Goodall Y., Grillo M., Getchell M., Danho W., et al. (1991). Vomeromodulin, a putative pheromone transporter cloning, characterization, and cellular-localization of a novel glycoprotein of lateral nasal gland. FASEB J 5, 2976-2982. 

Griffiths, M., et al. Cloning of a human nucleoside transporter implicated in the cellular uptake of adenosine and chemotherapeutic drugs. Nat. Med. 1997, 3, 89-93. 

M. S. Brown. cDNA cloning of MEV, a mutant protein that facilitates cellular uptake of mevalonate, and identification of the point mutation responsible for its gain of function. J. Biol. Chem. 1992, 267, 23113-23121. 

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