Ecophysiology and distribution of the endemic leafless spurgeEuphorbia aphylla and the introducedE. tirucalli (Euphorbiaceae,Euphorbia sect.Tirucalli) in the Canary Islands

The leafless spurgeEuphorbia aphylla (Euphorbiaceae), an endemic species restricted to several of the Canary Islands where it inhabits coastal and arid localities, expresses Crassulacean Acid Metabolism (CAM) when it is subjected to summer drought. A flexible CAM is consistent with the general ecology of the species. It is the only member of sect.Tirucalli native to the Canary Islands and is at the north-western edge of the section's biogeographical range. The other members of the section have a paleotropic distribution and are found throughout Africa. Many of them are regarded as obligate CAM plants, includingE. tirucalli which was used as a comparison in ecophysiological experiments examining the response ofE. aphylla to drought and temperature.     

Peroxidase activity and structural transitions of cytochrome c bound to cardiolipin-containing membranes

During apoptosis, cytochrome c (cyt c) is released from intermembrane space of mitochondria into the cytosol where it triggers the caspase-dependent machinery. We discovered that cyt c plays another critical role in early apoptosis as a cardiolipin (CL)-specific oxygenase to produce CL hydroperoxides required for release of pro-apoptotic factors [Kagan, V. E., et al. (2005) Nat. Chem. Biol. 1, 223-232]. We quantitatively characterized the activation of peroxidase activity of cyt c by CL and hydrogen peroxide. At low ionic strength and high CL/cyt c ratios, peroxidase activity of the CL/cyt c complex was increased >50 times. This catalytic activity correlated with partial unfolding of cyt c monitored by Trp(59) fluorescence and absorbance at 695 nm (Fe-S(Met(80)) band). The peroxidase activity increase preceded the loss of protein tertiary structure. Monounsaturated tetraoleoyl-CL (TOCL) induced peroxidase activity and unfolding of cyt c more effectively than saturated tetramyristoyl-CL (TMCL). TOCL/cyt c complex was found more resistant to dissociation by high salt concentration. These findings suggest that electrostatic CL/cyt c interactions are central to the initiation of the peroxidase activity, while hydrophobic interactions are involved when cyt c's tertiary structure is lost. In the presence of CL, cyt c peroxidase activity is activated at lower H(2)O(2) concentrations than for isolated cyt c molecules. This suggests that redistribution of CL in the mitochondrial membranes combined with increased production of H(2)O(2) can switch on the peroxidase activity of cyt c and CL oxidation in mitochondria-a required step in execution of apoptosis.     

Influence of the inoculation time of high sugar content must on the formation of wine aroma

The addition of inocula of a commercially available strain of Saccharomyces cerevisiae to musts with a high initial sugar content at various fermentation stages induces variable changes in the different components of the volatile fraction of wine and, potentially, its sensory properties as well. Inoculation alters the concentration ratio between the 2,3-butanediol isomers and causes a decrease in acetates and ethyl ester content. We propose an analytical ratio to evaluate the aromatic quality of the wine.     

Characteristics of bird species using forest and agricultural land covers in southern Costa Rica

Our understanding of why tropical forest species differ in their ability to inhabit agroecosystems is limited, despite the link between this ability and the likelihood of population decline for species inhabiting regions undergoing widespread conversion of forest to agriculture. We used logistic regression and data from southern Costa Rica to develop a model based on natural history characteristics to distinguish between forest species that did or did not use agricultural land covers. We sampled birds along 15 3.0-km routes, seven in forest and eight in agriculture, five times over three years. Each species was classified as an F-species, detected only in forest, a G-species, detected in both forest and agriculture, or an A-species, detected only in agriculture. Thirty percent of species were F-species, 42% were G-species, and 28% were A-species. Based on the logistic regression model, the likelihood of being a G-species, as opposed to an F-species, was low for species that were dependent on forest interior, had a stenophagous diet, and a small elevational range. Weight, resident versus migrant status, and whether or not a species was insectivorous, were not significant predictors of being a G-species. For all F–G species pairs, the model correctly predicted the G-species 70% of the time. The model provides a first step in identifying those characteristics that predispose forest species to use agricultural land. In addition, our results indicate that the structurally simple agricultural systems of the study region are of limited value for a large proportion of the regional species pool.     

Testing the association between residential fungus and health using ergosterol measures and cough recordings

Questionnaire surveys in several countries have consistently detected an association between symptoms and residential mould growth. Confirmation by objective measures would strengthen the argument for causality. To address this issue, quantitative and qualitative fungal measures (airborne ergosterol and viable fungi in dust) were compared to respiratory symptoms (n = 403) and nocturnal cough recordings (n = 145) in Canadian elementary schoolchildren during the winter of 1993–1994. There was a 25 percent to 50 percent relative increase in symptom prevalence when mould was reported to be present (p < 0.05). However, neither symptoms nor recorded cough was related to objective measures of mould. In conclusion, the inability to find an association between objective measures of fungus and health suggest that either these objective measures, or the traditionally used questionnaire data are inaccurate. This discrepancy limits the acceptance of a causal relation between indoor fungal growth and illness.This revised version was published online in October 2005 with corrections to the Cover Date.     

Sustainable use of wildlife: The view from archaeozoology

The concept of “sustainable use” is a polemic, especially when referring to wildlife and other “natural resources.” Claims vary from persistent overuse to traditional practices of sustaining the resource base. Arguments for either side routinely draw from contemporary situations, relying on relatively short time periods. But, if the notion “sustainable” is to be consequential, the period under consideration must be meaningful – claims that trends over a few years or even decades are representative of long-term phenomena are questionable, for they depend on numerous untested, if not untestable, assumptions. Research in anthropology, biology, biological conservation, ecology, policy, restoration ecology, social development, and wildlife management is routinely constrained to relatively short time periods, and such results are of limited value for evaluating sustainable use. Archaeozoology provides unique tools for investigating trends in human-resource relations over periods of centuries and millennia; it is one of the few disciplines explicitly dedicated to the study of material evidence over significant time periods that bears directly on the question of sustainable use. Hence, objective, scientific evaluation of sustainable use must contemplate archaeozoological evidence.Yet, archaeozoology often does not provide definitive answers: it is wrought with fundamental problems in sampling, data gathering, analysis, and interpretation (e.g., varying screen sizes; meta-sampling procedures; comparisons across diverse spatial, temporal, and environmental continua; etc.). Typically data must be evaluated through inference, rather than through direct observations and experiments. Moreover, environmental variation (e.g., climate change, sea level change, tectonic movement, etc.), as well as changes in societies, confounds the interpretation of long-term human–environmental trends. But, those challenges are not unique to archaeozoology, for biological and ecological phenomena are no less subject to multiple sources of environmental and social variation. The difference is that archaeologists are patently cognizant of these sources of variability, and they openly debate them when interpreting data, while in other disciplines these sources of change are routinely ignored. Nonetheless, despite the unique relevance of their work, few archaeozoologists have ventured outside their discipline to engage natural scientists and policy makers in issues of biological conservation and wildlife biology, and particularly the root questions of sustainable use. In addition to considering data and hypotheses regarding long-term prehistoric human–wildlife interactions, it is essential to view this information within broader perspectives, linked to other disciplines as well as to contemporary social and policy issues. Because sustainable use is mandated in international instruments and national policies, the notion has relevance in arenas far beyond academia, where archaeozoologists must be integrated into interdisciplinary teams.