A Dietary Risk Assessment for Indigenous Consumption of Natural Salt Deposits in the Darhad Valley,Northern Mongolia

The nomadic herding population of the Darhad Valley, in northern Mongolia, collects and utilizes a salt precipitate, called hujir, which develops at the saline system, Tohi. This culturally important indigenous dietary supplement is consumed daily as an ingredient in a salty milk-tea and because of its essential micro- and macronutrients it is a beneficial and necessary part of their daily diet. Despite its benefits, there are increasing health concerns among the Darhad people as a result of consuming hujir. Therefore, we conducted a dietary risk assessment. Consumption rates were obtained from interviews with nomadic herders of the valley and a chronic exposure assessment was completed using chemical analyses on hujir samples. A combination of chronic toxicity threshold values, dietary reference intake recommendations, and drinking water guidelines were used to estimate dietary risks related to hujir consumption. Exposures to arsenic, fluoride, and nitrate were as high as 33, 1.2, and 1.3 times the chronic oral reference dose, respectively. Exposures to antimony, arsenic, and lead were 1.7, 19, and 14 times the drinking water guidelines, respectively. Given these results, additional studies are needed to better understand possible health effects associated with hujir consumption in the Darhad population, especially for arsenic.     

Hot topics in aging research: protein translation, 2009

In the last few years, links between regulation of mRNA translation and aging have been firmly established in invertebrate model organisms. This year, a possible relationship between mRNA translation and aging in mammals has been established with the report that rapamycin increases lifespan in mice. Other significant findings have connected translation control with other known longevity pathways and provided fodder for mechanistic hypotheses. Here, we summarize advances in this emerging field and raise questions for future studies.     

Niche conservatism as an emerging principle in ecology and conservation biology

The diversity of life is ultimately generated by evolution, and much attention has focused on the rapid evolution of ecological traits. Yet, the tendency for many ecological traits to instead remain similar over time [niche conservatism (NC)] has many consequences for the fundamental patterns and processes studied in ecology and conservation biology. Here, we describe the mounting evidence for the importance of NC to major topics in ecology (e.g. species richness, ecosystem function) and conservation (e.g. climate change, invasive species). We also review other areas where it may be important but has generally been overlooked, in both ecology (e.g. food webs, disease ecology, mutualistic interactions) and conservation (e.g. habitat modification). We summarize methods for testing for NC, and suggest that a commonly used and advocated method (involving a test for phylogenetic signal) is potentially problematic, and describe alternative approaches. We suggest that considering NC: (1) focuses attention on the within‐species processes that cause traits to be conserved over time, (2) emphasizes connections between questions and research areas that are not obviously related (e.g. invasives, global warming, tropical richness), and (3) suggests new areas for research (e.g. why are some clades largely nocturnal? why do related species share diseases?).     

Proposed rule: current good manufacturing practice in manufacturing, packing, or holding dietary ingredients and dietary supplements

The Dietary Supplement Health and Education Act (DSHEA) was enacted in October 1994 to promote the health of Americans by ensuring easier access to safe dietary supplements. Many supplements such as vitamins, minerals, herbs and amino acids have been reported to be helpful in chronic conditions (i.e., heart disease, cancer and osteoporosis). Under DSHEA, dietary supplements can be marketed without prior FDA approval; the burden is on this agency to show that a marketed dietary supplement is unsafe. However, DSHEA retained the FDA's authority to issue regulations that require the manufacture of dietary supplements be in compliance with current good manufacturing practice (cGMP) standards, which are needed to ensure their quality. Several quality-related concerns of marketed dietary supplements that came to light since the passage of DSHEA prompted the FDA in 2003 to propose rules for cGMP for the manufacture, packaging and holding (storage) of dietary supplements. This review will present the highlights of these proposed rules, focusing on the legislative history of DSHEA, rationale for proposing cGMPs along with a general discussion of the specific requirements. Given the voluminous nature of the specific details, the reader is directed to the pertinent FDA publications for details. In this analysis, selected scientific and legal issues are also discussed to promote a better understanding and implications of these rules.     

Complex patterns of environmental niche evolution in Iberian columbines (genus Aquilegia,Ranunculaceae)

Aims This study explores the patterns of niche differentiation in a group of seven closely related columbines (genus Aquilegia, Ranunculaceae) from the Iberian Peninsula. Populations of these columbines are subject to complex patterns of divergent selection across environments, which partly explain the taxonomic structure of the group. This suggests the hypothesis that niche divergence must have occurred along the process of diversification of the group.Methods We used MaxEnt to build environmental niche models of seven subspecies belonging to the three species of Aquilegia present in the Iberian Peninsula. From these models, we compared the environmental niches through two different approaches: ENMtools and multivariate methods.Important findings MaxEnt distributions conformed closely to the actual distribution of the study taxa. ENMtools methods failed to uncover any clear patterns of niche differentiation or conservatism in Iberian columbines. Multivariate analyses indicate the existence of differentiation along altitudinal gradients and along a gradient of climatic conditions determined by the summer precipitation and temperatures. However, climatic conditions related to winter temperature and precipitation, as well as soil properties, were equally likely to show conservatism or divergence. The complex patterns of niche evolution we found suggest that Iberian Columbines have not been significantly constrained by forces of niche conservatism, so they could respond adaptively to the fast and profound climate changes in the Iberian Peninsula through the glacial cycles of the Pleistocene.     

The Investigation on Utilization of Wild Medicinal Plants in Dietary Culture of Quanzhou,Southern Fujian

An ethnobotanical survey on the medicinal plant species marketed in Quanzhou, southern Fujian, was conducted in order to document traditional medicinal knowledge and application of medicinal plants in dietary. In addition to literature review, data was obtained using ethnobotanical tools and methods, including personal interviews during field trips, collecting herbarium specimens, and species identification by cross referencing. The results showed that: 1) There are 148 wild medicinal species, belonging to 56 plant families and 117 genera present in Quanzhou, southern Fujian. Among them, 46 species are edible wild herbs, 37 species are medicinal plants, 38 species are used as tea substituting plants or herbal tea,22 species are wild fruits, 4 species are used as spices and 1 species is used to make bean jelly; 2) The plant families which comprise a major part of the pool are Compositae, Lamiaceae, Rosaceae, Leguminosae, Rubiaceae, Liliaceae, Orchidaceae and Moraceae; 3) This study explored the utilization of the medicinal plants in Quanzhou area, and proposed methods to inherit the culture of using wild plants in dietary, as well as methods to conserve the edible medicinal wild plant resources.     

Health risk assessment of Chinese consumers to lead via diet

This paper investigated the concentrations of Pb in foods and the potential health risk from Pb exposure via surveys and a literature review. It was shown that the mean Pb concentration in different food groups was in the following decreasing order: marine products > meat > egg > vegetable > cereal > bean> dairy > fruit. More precisely, on average the weekly Pb intake (mg kg^?1 bw week^?1) for men, women, 2–3-year-old children, and 4–17-year-old children was 0.0055, 0.0059, 0.0145, and 0.0091, respectively. We used both deterministic and probabilistic methods to estimate the target hazard quotients (THQs) by comparing the dietary Pb intake estimation with respect to the provisional tolerable weekly intake (PTWI). The result showed that THQ values were lower than 1 in most cases, except the 97.5th percentile THQ values for 2–3-year-old children, and the probability of greater dietary Pb exposure than the tolerant weekly intake (THQ > 1) were 0.2%, 0.6%, 3.7%, and 1.2% for adult men, women, 2–3-year-old children, and 4–17-year-old children, respectively, indicating a low health risk for Chinese consumers. Among all groups, children, especially 2–3-year-old children were the most sensitive sub-population with regard to Pb exposure. Finally, it still appeared necessary to continue undertaking efforts to reduce exposure to Pb.     

Evolutionary and environmental determinants of freshwater fish thermal tolerance and plasticity

Understanding the extent to which phylogenetic constraints and adaptive evolutionary forces help define the physiological sensitivity of species is critical for anticipating climate‐related impacts in aquatic environments. Yet, whether upper thermal tolerance and plasticity are shaped by common evolutionary and environmental mechanisms remains to be tested. Based on a systematic literature review, we investigated this question in 82 freshwater fish species (27 families) representing 829 experiments for which data existed on upper thermal limits and it was possible to estimate plasticity using upper thermal tolerance reaction norms. Our findings indicated that there are strong phylogenetic signals in both thermal tolerances and acclimation capacity, although it is weaker in the latter. We found that upper thermal tolerances are correlated with the temperatures experienced by species across their range, likely because of spatially autocorrelated processes in which closely related species share similar selection pressures and limited dispersal from ancestral environments. No association with species thermal habitat was found for acclimation capacity. Instead, species with the lowest physiological plasticity also displayed the highest thermal tolerances, reflecting to some extent an evolutionary trade‐off between these two traits. Although our study demonstrates that macroecological climatic niche features measured from species distributions are likely to provide a good approximation of freshwater fish sensitivity to climate change, disentangling the mechanisms underlying both acute and chronic heat tolerances may help to refine predictions regarding climate change‐related range shifts and extinctions.     

Pollinator adaptation and the evolution of floral nectar sugar composition

A long‐standing debate concerns whether nectar sugar composition evolves as an adaptation to pollinator dietary requirements or whether it is ‘phylogenetically constrained’. Here, we use a modelling approach to evaluate the hypothesis that nectar sucrose proportion (NSP) is an adaptation to pollinators. We analyse ~ 2100 species of asterids, spanning several plant families and pollinator groups (PGs), and show that the hypothesis of adaptation cannot be rejected: NSP evolves towards two optimal values, high NSP for specialist‐pollinated and low NSP for generalist‐pollinated plants. However, the inferred adaptive process is weak, suggesting that adaptation to PG only provides a partial explanation for how nectar evolves. Additional factors are therefore needed to fully explain nectar evolution, and we suggest that future studies might incorporate floral shape and size and the abiotic environment into the analytical framework. Further, we show that NSP and PG evolution are correlated – in a manner dictated by pollinator behaviour. This contrasts with the view that a plant necessarily has to adapt its nectar composition to ensure pollination but rather suggests that pollinators adapt their foraging behaviour or dietary requirements to the nectar sugar composition presented by the plants. Finally, we document unexpectedly sucrose‐poor nectar in some specialized nectarivorous bird‐pollinated plants from the Old World, which might represent an overlooked form of pollinator deception. Thus, our broad study provides several new insights into how nectar evolves and we conclude by discussing why maintaining the conceptual dichotomy between adaptation and constraint might be unhelpful for advancing this field.