Wild clocks: preface and glossary

No abstract available

The 1993 Gordon Research Conference on Chronobiology

The study of biological timekeeping is now at a particularly fertile stage, encompassing multiple levels of biological organization, recruiting a wide array of disciplines and methodologies and uniting a host of investigators. This report summarizes a research conference on Chronobiology. Some of the topics focused on transcriptional and translational mechanisms of circadian rhythmicity, with discussions of putative 'clock genes' in cyanobacteria, algae, fungi, fruitflies, and hamsters. Cellular analysis, with emphasis on photoreceptors in frogs, neurons in molluscs, and testis in moths was addressed. New methods for investigating the circadian clock in the suprachiasmatic nucleus were introduced

Circadian timekeeping in BALB/c and C57BL/6 inbred mouse strains

Circadian rhythms of locomotion (wheel-running activity) in 12 inbred mouse strains were recorded for interstrain differences in tau DD, the endogenous (free-running) period of the circadian pacemaker measured in constant environmental darkness. The results indicate that 1 or more genetic loci influence the value of tau DD, and a large (50 min) difference in mean tau DD between 2 of the strains, BALB/cByJ and C57BL/6J, allowed further characterization of the origins and inheritance of the polymorphic expression of this circadian pacemaker property. The interstrain difference in mean tau DD was associated with an interstrain difference in light-induced shifts of the phase of the free-running locomotor rhythm; the BALB/c strain (with the shorter mean tau DD) displayed relatively fewer advance phase shifts. Neither the history of previous light exposure, albinism, nor elevated circulating testosterone levels could account for the interstrain difference in mean tau DD. The value of tau DD based on the circadian rhythm of drinking activity (with the running wheel removed) was longer than that based on locomotion; this discrepancy was significantly greater and more variable in BALB/c than in C57BL/6 mice, though the interstrain difference in mean tau DD could not be attributed entirely to this effect. Reciprocal F1 hybrids of BALB/c x C57BL/6 matings revealed dominance of the C57BL/6 genotype, no sex linkage, and a significant (but small) maternal effect. Examination of CXB recombinant inbred strains provided no support for the hypothesis of monogenic inheritance. Further study of inherited differences in the BALB/c and C57BL/6 strains may be a useful noninvasive experimental approach for investigation of the neurobiological substrates of circadian rhythmicity

Origins:A brief account of the ancestry of circadian biology

Who were the investigators and what was the path that enabled the launch of modern mechanistic research on circadian biology in the 1970s? Here we trace the origins of ideas from antiquity to the experimental study of the daily movements of leaves; on to the twentieth-century realization that circadian rhythms are widespread, endogenous, and innate; and finally to the appreciation that such rhythms could be utilized by organisms for the measurement of time. The conceptualization of the internal "clock" metaphor was key to the wave of mathematical, neurobiological, and molecular genetic advances that has transformed the field over the last 50 years.</p

Mollusks of the Cheat River Watershed of West Virginia and Pennsylvania, with Comments on Present Distributions

Author Institution: Chesapeake Biological Laboratory, Solomons, Maryland and Mt. St. Mary's College, Emmitsburg, Marylan

Memory decrement and proactive interference

We hypothesized that subjective expectations were responsible for the release from proactive interference (PI) rather than the actual change in taxonomic subcategories. The experimental conditions included informing or not informing subjects of the change in taxonomic subcategory, crossed with whether the taxonomic subcategory was actually changed or remained unchanged. The interest in whether a release would be seen when the subjects were informed of a change, yet no change was actually administered, was most specific. Significantly higher recall was found for the condition in which subjects were informed of a change, but no actual change occured (I-NC) than in the control condition in which subjects were neither informed of a change nor did one occur (NI-NC). The overall results indicated that control conditions revealed lower recall than other conditions, F(3, 129) = 2.96. p \u3c .05 on the critical trial. However, even when subjects were not told of a change, but a change occured (NI-C) a release from PI was observed, M=.69. A release from PI may be induced by the subject\u27s self-awareness of the change in taxonomic subcategory