Developmental asynchrony caused by steep temperature gradients does not impair pattern formation in the wasp,Pimpla turionellae L.

Generating developmental gradients by temperature gradients established within a developing organism is an easy, non-invasive technique to study physiological interdependencies between locally separated subsystems. A linear temperature gradient of about 10° C/mm was maintained up to 5 h in either direction along the long axis of a long-germ-type hymenopteran egg, which was simultaneously filmed by the 16 mm timelapse technique. The result was a dramatic desynchronization of development, which between the egg poles could reach up to 9.3 h relative to normal development. Within the same egg, up to seven mitotic waves (i.e. eight different nuclear generations) were observed at the same time, and the subsequent cellularization process was extremely asynchronous. The initial regions of the mitotic waves, the fountain flow of the ooplasm, and the gastrulation process were shifted towards the egg pole kept at higher temperatures. Developmental processes occurring successively in normal development now took place simultaneously, with either direction of the temperature gradient. For instance, while gastrulation had started in the warm region, midblastula transition and cellularization were in progress in the middle of the egg, and intravitelline nuclear multiplication occurred at the cold pole, by rapid and still biphasic cell cycles. In some respects, development resembled that of a short-germ-type insect egg. Nevertheless, the developmental processes were resynchronized after the temperature gradient was switched off. Surprisingly, the extreme desynchronization during early development did not affect the segment pattern of the resulting embryos. The technique of inducing well-defined developmental asynchronies might be applied in Drosophila to analyse the subtle interplay between maternal and zygotic gene activities described in this species.     

Quantitative in vivo redox sensors uncover oxidative stress as an early event in life

Obstacles in elucidating the role of oxidative stress in?aging include difficulties in (1) tracking in?vivo oxidants, in (2) identifying affected proteins, and in (3) correlating changes in oxidant levels with life span. Here, we used quantitative redox proteomics to determine the onset and the cellular targets of oxidative stress during Caenorhabditis elegans' life span. In parallel, we used genetically encoded sensor proteins to determine peroxide levels in live animals in real time. We discovered that C.?elegans encounters significant levels of oxidants as early as during larval development. Oxidant levels drop rapidly as animals mature, and reducing conditions prevail throughout the reproductive age, after which age-accompanied protein oxidation sets in. Long-lived daf-2 mutants transition faster to reducing conditions, whereas short-lived daf-16 mutants retain higher oxidant levels throughout their mature life. These results suggest that animals with improved capacity to recover from early oxidative stress have significant advantages later in life.     

Effect of wind energy development on breeding duck densities in the Prairie Pothole Region

Industrial wind energy production is a relatively new phenomenon in the Prairie Pothole Region and given the predicted future development, it has the potential to affect large land areas. The effects of wind energy development on breeding duck pair use of wetlands in proximity to wind turbines were unknown. During springs 2008–2010, we conducted surveys of breeding duck pairs for 5 species of dabbling ducks in 2 wind energy production sites (wind) and 2 paired reference sites (reference) without wind energy development located in the Missouri Coteau of North Dakota and South Dakota, USA. We conducted 10,338 wetland visits and observed 15,760 breeding duck pairs. Estimated densities of duck pairs on wetlands in wind sites were lower for 26 of 30 site, species, and year combinations and of these 16 had 95% credible intervals that did not overlap zero and resulted in a 4–56% reduction in breeding pairs. The negative median displacement observed in this study (21%) may influence the prioritization of grassland and wetland resources for conservation when existing decision support tools based on breeding-pair density are used. However, for the 2 wind study sites, priority was not reduced. We were unable to directly assess the potential for cumulative impacts and recommend long-term, large-scale waterfowl studies to reduce the uncertainty related to effects of broad-scale wind energy development on both abundance and demographic rates of breeding duck populations. In addition, continued dialogue between waterfowl conservation groups and wind energy developers is necessary to develop conservation strategies to mitigate potential negative effects of wind energy development on duck populations. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

Win-win for wind and wildlife: a vision to facilitate sustainable development

Wind energy offers the potential to reduce carbon emissions while increasing energy independence and bolstering economic development. However, wind energy has a larger land footprint per Gigawatt (GW) than most other forms of energy production, making appropriate siting and mitigation particularly important. Species that require large unfragmented habitats and those known to avoid vertical structures are particularly at risk from wind development. Developing energy on disturbed lands rather than placing new developments within large and intact habitats would reduce cumulative impacts to wildlife. The U.S. Department of Energy estimates that it will take 241 GW of terrestrial based wind development on approximately 5 million hectares to reach 20% electricity production for the U.S. by 2030. We estimate there are ～7,700 GW of potential wind energy available across the U.S., with ～3,500 GW on disturbed lands. In addition, a disturbance-focused development strategy would avert the development of ～2.3 million hectares of undisturbed lands while generating the same amount of energy as development based solely on maximizing wind potential. Wind subsidies targeted at favoring low-impact developments and creating avoidance and mitigation requirements that raise the costs for projects impacting sensitive lands could improve public value for both wind energy and biodiversity conservation.     

Thermotaxis and protoplasmic oscillations inPhysarum plasmodia analysed in a novel device generating stable linear temperature gradients

Summary The application of sublethal temperature gradients offers a simple, non-invasive means for in vivo studies of thermotaxis and other temperature-dependent processes in various organisms. Development, for instance, can be dramatically desynchronized, and the resulting development gradients allow to analyze physiological inter-dependencies between locally separated subsystems. For this purpose a simple device has been developed, by which a stable linear gradient of 8 °C/cm is established on an inert metal sheet with the aid of Peltier elements. The effects of linear temperature gradients on fusion, growth, and migration of plasmodia of the slime moldPhysarum polycephalum was filmed by 16 mm film time-lapse technique, and their local contraction—relaxation cycles analysed by multistrip kymography, which represents a graphic documentation of the spatio-temporal pattern of protoplasmic movements that occur along well-defined regions within the giant cell.Physarum plasmodia preferentially fuse, and grow, in the range of 24–26 °C. Different parts of a single macroplasmodium can simultaneously show positive and negative thermotaxis. The contraction—relaxation cycles generating the protoplasmic shuttle streaming within the network of veins essentially depend on local temperatures and are instantaneously desynchronized by the temperature gradient. Thus they cannot be controlled by a central pacemaker or an overall electric signal. However, there is a strong tendency to locally synchronize the various oscillation frequencies present within the giant cell if temperature differences do not exceed 2 °C.