Phenotypic Curing

Interestingly, Rosenkranz et a/. have reported occasional false-positive results with Amitrole and have attributed them to phenotypic curing. It is not known whether this phenotypic curing is due to Amitrole acting as a histidine analogue in protein synthesis or as a ribonucleic acid analogue in messenger RNA synthesis. 

As previously mentioned, phenotypic curing was observed with Amitrole and resulted in what could be falsely interpreted as positive results. Similarly, bactericidal chemicals can produce false positives by cross-feeding of histidine released by killed bacteria to surviving bacteria a large number of pinpoint colonies is suggestive of this activity. This has prompted Rosenkranz et to recommend that routine testing include replica plating of some positive plates onto minimal media supplemented with biotin to control for these phenotypic effects. 

Chapter III - Considerable effort and means have been invested to find treatments for neurological diseases and injuries, yet there is still no cure for these ailments, and new alternatives for therapy must be explored. Because they generate the main phenotypes of the... 

Chapter VIII - The central nervous system (CNS) elicits limited capacity to recover from injury. Though considerable efforts and means have been deployed to find treatments for neurological diseases, disorders and injuries, there is still no cure for these ailments, and new alternatives for therapy must be explored. Because they generate the main phenotypes of the nervous system, neural stem cells (NSCs) hold the promise to cure a broad range of neurological diseases and injuries. With the confirmation that neurogenesis occurs in the adult... 

To facilitate our work on plasmids with no known phenotype, we have developed a method for the use and detection of biotinylated probes in colony hybridization. It is suitable both for the detection of rare positive hybridization events over a background of nonreactive colonies and for the detection of nonhybridizing colonies in a population containing sequences homologous to the probe. The latter capability could be useful in such applications as the detection of cured (i.e., plasmid-free) cells in a bacterial population containing plasmids. 

Confidence in the estimates of human dominant disease and skeletal defects may be increased by obtaining independent estimates based on essentially the same procedure, but with cataracts as the dominant phenotype.108 220 Although neither skeletal defects nor cataracts cure very precisely measured phenotypes, the risk estimates for radiation based on them are in reasonable agreement. 

COMPLEMENTATION The ability of recessive mutations in two different segments of DNA that cure involved in deter-mining the same phenotype to interact in such a way that, when both are present, a nonmutant phenotype results. 

When placed under the regulation of an inducible promoter, HSP104 cures [PSP] only in response to the induction stimulus (Cher-noff et al, 1995). Notably, transient overexpression of Hspl04 is sufficient to cure [PSP], and when Hspl04 levels are returned to normal, the [psi ] state persists (Chernolf et al., 1995). Thus, a transient increase in Hspl04 levels is sufiticient to induce a heritable change in phenotype in yeast. 

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