A field-portable racetrack and timer for measuring acceleration and speed of small cursorial animals

Summary We describe a relatively inexpensive, field-portable racetrack and timer that can be used to measure acceleration and maximum speed of small cursorial animals. Procedures for interfacing the racetrack to microprocessors are also outlined.This research was supported by NSF DEB 78-12124, the Miller Institute for Basic Research in Science (University of California, Berkeley), and by the Graduate School Research Fund (University of Washington, Seattle). The authors gladly acknowledge the advice of R. Reinstatler, J.R. Simpson, M.O. Smith, and especially A. M. Hawkins.     

Global metabolic impacts of recent climate warming

Documented shifts in geographical ranges, seasonal phenology, community interactions, genetics and extinctions have been attributed to recent global warming. Many such biotic shifts have been detected at mid- to high latitudes in the Northern Hemisphere-a latitudinal pattern that is expected because warming is fastest in these regions. In contrast, shifts in tropical regions are expected to be less marked because warming is less pronounced there. However, biotic impacts of warming are mediated through physiology, and metabolic rate, which is a fundamental measure of physiological activity and ecological impact, increases exponentially rather than linearly with temperature in ectotherms. Therefore, tropical ectotherms (with warm baseline temperatures) should experience larger absolute shifts in metabolic rate than the magnitude of tropical temperature change itself would suggest, but the impact of climate warming on metabolic rate has never been quantified on a global scale. Here we show that estimated changes in terrestrial metabolic rates in the tropics are large, are equivalent in magnitude to those in the north temperate-zone regions, and are in fact far greater than those in the Arctic, even though tropical temperature change has been relatively small. Because of temperature's nonlinear effects on metabolism, tropical organisms, which constitute much of Earth's biodiversity, should be profoundly affected by recent and projected climate warming.     

Drosophila hygrosensation requires the TRP channels water witch and nanchung

The ability to detect variations in humidity is critical for many animals. Birds, reptiles and insects all show preferences for specific humidities that influence their mating, reproduction and geographic distribution. Because of their large surface area to volume ratio, insects are particularly sensitive to humidity, and its detection can influence their survival. Two types of hygroreceptors exist in insects: one responds to an increase (moist receptor) and the other to a reduction (dry receptor) in humidity. Although previous data indicated that mechanosensation might contribute to hygrosensation, the cellular basis of hygrosensation and the genes involved in detecting humidity remain unknown. To understand better the molecular bases of humidity sensing, we investigated several genes encoding channels associated with mechanosensation, thermosensing or water transport. Here we identify two Drosophila melanogaster transient receptor potential channels needed for sensing humidity: CG31284, named by us water witch (wtrw), which is required to detect moist air, and nanchung (nan), which is involved in detecting dry air. Neurons associated with specialized sensory hairs in the third segment of the antenna express these channels, and neurons expressing wtrw and nan project to central nervous system regions associated with mechanosensation. Construction of the hygrosensing system with opposing receptors may allow an organism to very sensitively detect changes in environmental humidity.     

Assembly of microarrays for genome-wide measurement of DNA copy number.

We have assembled arrays of approximately 2,400 BAC clones for measurement of DNA copy number across the human genome. The arrays provide precise measurement (s.d. of log2 ratios=0.05-0.10) in cell lines and clinical material, so that we can reliably detect and quantify high-level amplifications and single-copy alterations in diploid, polyploid and heterogeneous backgrounds.