Publications

Methodological advances now permit human biologists to more effectively monitor energy dynamics in traditional societies. This study examines the nutritional ecology and energetics of semisubsistence herders of Siberia (Evenki) during a single season of their annual cycle (late summer). Total energy expenditure (TEE) among adults, as measured by daily heart-rate monitoring, is greater in Evenki men (TEE = 11.9 ± 2.8 MJ/d in men and 8.8 ± 2.1 MJ/d in women; P < 0.001), a pattern that reflects the current division of labor under collectivized herding systems. Energy intakes are also greater among men (13.4 ± 5.6 vs. 8.5 ± 3.4 MJ/d; P < 0.01), and are, on average, sufficient to meet daily needs in both sexes. The Evenki appear to be in energy balance at the population level during the late summer (per capita energy intake = 9.0 ± 5.5 MJ/person/d; per capita requirements = 8.6 MJ/person/d); however, only small changes in food availability and/or energy expenditure are necessary to shift the population into negative balance during the winter. Primary sources of dietary energy include reindeer meat and other animal products (25-30%), foraged plant foods (10-15%), and nonlocal products (55-65%), such as flour, rice, and sugar. The anthropometric data indicate that the Evenki grow slowly and have small adult body size. Women are relatively heavier and fatter than men, and show a centripetal pattern of fat distribution. Evenki males appear to be undergoing a secular trend in stature, while no such increases are evident in females. These gender differences may reflect the differential impact to the changes associated with collectivization. Reduced metabolic requirements (due to declining activity and fertility levels), along with greater food availability, are likely to be responsible for the higher rates of obesity among Evenki women. © 1996 Wiley-Liss, Inc.

Each G protein-coupled receptor recognizes only a distinct subset of the many structurally closely related G proteins expressed within a cell. How this selectively is achieved at a molecular level is not well understood, particularly since no specific point-to-point contact sites between a receptor and its cognate G protein(s) have been identified. In this study, we demonstrate that a 4-aa epitope on the m2 muscarinic acetylcholine receptor, a prototypical Gi/o-coupled receptor, can specifically recognize the C-terminal 5 aa of alpha subunits of the Gi/o protein family. The m2 receptor residues involved in this interaction are predicted to be located on one side of an alpha-helical receptor region present at the junction between the third intracellular loop and the sixth transmembrane domain. Coexpression studies with hybrid m2/m3 muscarinic receptors and mutant G-protein alpha q subunits showed that the receptor/G-protein contact site identified in this study is essential for coupling specificity and G-protein activation.