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Biomedical subjects

R Lahue

Publications and source records attributed to R Lahue.

8 recordsLinked to original sources

Mismatch repair in replication fidelity, genetic recombination, and cancer biology.

Mismatch repair stabilizes the cellular genome by correcting DNA replication errors and by blocking recombination events between divergent DNA sequences. The reaction responsible for strand-specific correction of mispaired bases has been highly conserved during evolution, and homologs of bacterial MutS and MutL, which play key roles in mismatch recognition and initiation of repair, have been identified in yeast and mammalian cells. Inactivation of genes encoding these activities results in a large increase in spontaneous mutability, and in the case of mice and men, predisposition to tumor development.

Animals↗

Telson reflex habituation in Limulus polyphemus.

Muscle correlates of reflex telson movement were recorded in intact Limulus (horseshoe crab) preparations with chronically implanted microelectrodes. Muscle activity habituated during repetitive tactile stimulation of the gills with puffs of air. Dishabituation was also observed, as were inverse relationships between the frequency and intensity of stimulation and the rate of response decrement. These findings closely paralleled those obtained during central recordings in acute dissected preparations, as did the demonstration under certain stimulation conditions of an initial incremental phase of responsivity. Although initial levels of responsivity recovered after 1 hr without stimulation, potentiation of habituation was observable after 2 hr. Both of these times greatly exceeded those previously observed in acute preparations. No generalization to a spatial displacement of the stimulus was obtained, although a visually elicited telson reflex had been shown to demonstrate a cross-optic generalization. Aspects of the comparative strategy and the adaptive value of telson reflex habituation in Limulus were briefly considered.

Animals↗