How Can Stomata Contribute to Salt Tolerance?

Although some of the physiological mechanisms which contributeto salt tolerance in plants are known, there are still somemajor gaps in understanding and it remains impossible to providea satisfactory integrated picture for the plant as a whole.The operation of stomata in halophytes has received little attentioneven though all of the salt present in the shoot (apart fromthat taken in during submergence) is thought to be carried inthe transpiration stream. In non-halophytes, stomatal functionis damaged by sodium ions, and disruption of the normal regulationof transpiration should be seen as a possible contributor totheir inability to survive in salt-laden soils. The developmentof salt-tolerant cultivars of crops may require attention tothe need for appropriate adaptations to the ionic relationsof stomatal guard cells. Despite the small amount of evidenceavailable, it is possible to identify two alternative adaptationsthat occur in the stomata of halophytes: (1) the guard cellscan utilize Na⁺instead of K⁺to achieve their normal regulationof turgor; (2) the guard cells continue to use K⁺and are ableto limit their intake of Na⁺. The second adaptation is worthyof further exploration because it may provide a means for ‘topdown’ control of transpiration and, therefore, of theamount of salt delivered to the shoot. This mechanism may bevery important in some of the glandless halophytes, and it couldbe of particular interest as a potential contributor to thedevelopment of salt tolerance in crops. Salt tolerance; stomata; transpiration; halophytes; ionic regulation; sodium ions     

Do Pollinators Contribute to Nutritional Health?

Despite suggestions that animal pollinators are crucial for human nutritional health, no studies have actually tested this claim. Here, we combined data on crop pollination requirements, food nutrient densities, and actual human diets to predict the effects of pollinator losses on the risk of nutrient deficiency. In four developing countries and across five nutrients, we found that 0 to 56% of populations would become newly at risk if pollinators were removed. Increases in risk were most pronounced for vitamin A in populations with moderate levels of total nutrient intake. Overall, the effects of pollinator decline varied widely among populations and nutrients. We conclude that the importance of pollinators to human nutrition depends critically on the composition of local diets, and cannot be reliably predicted from global commodity analyses. We identify conditions under which severe health effects of pollinator loss are most likely to occur.     

The State of Research on Human–Animal Relations: Implications for Human Health

ABSTRACT

Since the late 1970s, scientific evidence has accumulated showing that pet ownership can have positive effects on people’s physical and mental wellbeing. This paper reviews the current state of affairs regarding the relationship between companion animals and human health, focusing on both the physical and psychological health outcomes related to human–animal interactions. Although designed to set the general scene on the link between animals and human wellbeing, research specific to older adults is highlighted where relevant. A particular emphasis is placed on disorders prevalent in modern-day society, notably cardiovascular disease and depression. The possible mechanisms by which companion animals might be able to enhance human wellbeing and quality of life are discussed, focusing on routes including, amongst others, the provision of companionship, social lubrication, and improvements to physical fitness. The role of the social bonding hormone, oxytocin, in facilitating attachment to our pets and the implications for human health is also discussed. Inconsistencies in the literature and methodological limitations are highlighted throughout. It is concluded that future human–animal interaction experiments should aim to account for the confounding variables that are inherent in studies of this nature.     

What Distinguishes the Gordon Research Conference on Oceans and Human Health? A Retrospective 2008–2012

This piece is being submitted as a short commentary for the special edition on Oceans and Human Health (OHH). It is written from the perspective of a student who has attended all three biennial Gordon Research Conferences and Seminars on OHH beginning in 2008.     

How Do Plants Survive Ice?

Plant species have had to adapt to freezing and the presenceof ice in many climatic zones. Annual plants avoid ice by seeddispersal but, for biennials and perennials to survive theymust cope with ice in various forms. Most plants that are regularlyexposed to ice during their life cycles have acquired a dormantor quiescent winter period, when they are more tolerant to freezingtemperatures. This Botanical Briefing explores some associationsbetween plants and ice, with an emphasis on processes in plantsthat alleviate stress imposed by ice cover. Examples are takenfrom winter cereals which must reach an equilibrium both withice and with freezing temperatures for survival and economicproductivity. Acclimation; anaerobiosis; anoxia; cold; flooding; hypoxia; ice; ice encasement; winter survival     

Can Economic Analysis Contribute to Disease Elimination and Eradication? A Systematic Review

Background

Infectious diseases elimination and eradication have become important areas of focus for global health and countries. Due to the substantial up-front investments required to eliminate and eradicate, and the overall shortage of resources for health, economic analysis can inform decision making on whether elimination/eradication makes economic sense and on the costs and benefits of alternative strategies. In order to draw lessons for current and future initiatives, we review the economic literature that has addressed questions related to the elimination and eradication of infectious diseases focusing on: why, how and for whom?

Methods

A systematic review was performed by searching economic literature (cost-benefit, cost-effectiveness and economic impact analyses) on elimination/eradication of infectious diseases published from 1980 to 2013 from three large bibliographic databases: one general (SCOPUS), one bio-medical (MEDLINE/PUBMED) and one economic (IDEAS/REPEC).

Results

A total of 690 non-duplicate papers were identified from which only 43 met the inclusion criteria. In addition, only one paper focusing on equity issues, the “for whom?” question, was found. The literature relating to “why?” is the largest, much of it focusing on how much it would cost. A more limited literature estimates the benefits in terms of impact on economic growth with mixed results. The question of how to eradicate or eliminate was informed by an economic literature highlighting that there will be opportunities for individuals and countries to free-ride and that forms of incentives and/or disincentives will be needed. This requires government involvement at country level and global coordination. While there is little doubt that eliminating infectious diseases will eventually improve equity, it will only happen if active steps to promote equity are followed on the path to elimination and eradication.

Conclusion

The largest part of the literature has focused on costs and economic benefits of elimination/eradication. To a lesser extent, challenges associated with achieving elimination/eradication and ensuring equity have also been explored. Although elimination and eradication are, for some diseases, good investments compared with control, countries’ incentives to eliminate do not always align with the global good and the most efficient elimination strategies may not prioritize the poorest populations. For any infectious disease, policy-makers will need to consider realigning contrasting incentives between the individual countries and the global community and to assure that the process towards elimination/eradication considers equity.     

How to Explore Morphological Integration in Human Evolution and Development?

Most studies in evolutionary developmental biology focus on large-scale evolutionary processes using experimental or molecular approaches, whereas evolutionary quantitative genetics provides mathematical models of the influence of heritable phenotypic variation on the short-term response to natural selection. Studies of morphological integration typically are situated in-between these two styles of explanation. They are based on the consilience of observed phenotypic covariances with qualitative developmental, functional, or evolutionary models. Here we review different forms of integration along with multiple other sources of phenotypic covariances, such as geometric and spatial dependencies among measurements. We discuss one multivariate method [partial least squares analysis (PLS)] to model phenotypic covariances and demonstrate how it can be applied to study developmental integration using two empirical examples. In the first example we use PLS to study integration between the cranial base and the face in human postnatal development. Because the data are longitudinal, we can model both cross-sectional integration and integration of growth itself, i.e., how cross-sectional variance and covariance is actually generated in the course of ontogeny. We find one factor of developmental integration (connecting facial size and the length of the anterior cranial base) that is highly canalized during postnatal development, leading to decreasing cross-sectional variance and covariance. A second factor (overall cranial length to height ratio) is less canalized and leads to increasing (co)variance. In a second example, we examine the evolutionary significance of these patterns by comparing cranial integration in humans to that in chimpanzees.