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.     

Provision of nestboxes raises the breeding density of Great Tits Parus major equally in coniferous and deciduous woodland

Nestbox provision is a technique used to increase nest-site availability for secondary cavity-nesting birds. However, little is known about the demographic consequences of nestbox provision in different habitat types. To assess how nestbox provision affects the density of hole-nesting birds simultaneously in two contrasting habitats, we compared the breeding density of Great Tits along transects without nestboxes with that in transects where nestboxes were provided. Although the initial density of breeders was considerably higher in the deciduous habitat than in the coniferous habitat, provision of nestboxes increased density by a similar number of additional pairs in each habitat type. Thus, the provision of nestboxes in managed coniferous forests may be as effective in increasing the breeding opportunities of cavity nesters as in deciduous stands. Moreover, previous research showed that pairs in deciduous habitat with nestboxes have consistently lower breeding success than those in coniferous habitat with nestboxes. It is possible that the addition of nestboxes in the preferred habitat increased density to such an extent that density-dependent effects became apparent.     

The European Renal Genome Project: An Integrated Approach Towards Understanding the Genetics of Kidney Development and Disease

Rapid progress in genome research creates a wealth of information on the functional annotation of mammalian genome sequences. However, as we accumulate large amounts of scientific information we are facing problems of how to integrate and relate the data produced by various genomic approaches. Here, we propose the novel concept of an organ atlas where diverse data from expression maps to histological findings to mutant phenotypes can be queried, compared and visualized in the context of a three-dimensional reconstruction of the organ. We will seek proof of concept for the organ atlas by elucidating genetic pathways involved in development and pathophysiology of the kidney. Such a kidney atlas may provide a paradigm for a new systems-biology approach in functional genome research aimed at understanding the genetic bases of organ development, physiology and disease.Key Words: EuReGene, kidney, genome, development, pathophysiology, genetics     

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.