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.     

Effect of thawing regimens on the morphofunctional state of canine spermatozoa

The effect of 2 thawing regimens (37 degrees C for 8 sec and 55 degrees C for 5 sec) was followed up on semen parameters related to the viability of canine spermatozoa. The ejaculates were frozen in the form of pellets on dry ice in the following cryoprotective extenders: TRIS-fructose (TF), TRIS-glucose (TG), and sucrose-lactose (SL). For the 3 extenders, significant differences were found in the percentage of motile spermatozoa and their survival rate up to 300 min in favor of the 55 degrees C vs the 37 degrees C thawing regimens. Structural changes such as swelling, breakage and absence of acrosomes were observed in the samples frozen in the 3 cryoprotective extenders. A considerably lower percentage of spermatozoa with damaged acrosomes was recorded at 55 degrees C in comparison with that found at 37 degrees C (P < 0.05 for TG, TF and SL). Enzymocytochemical analysis was made of NADH-tetrazolium reductase activity in thawed spermatozoa. Cells showing moderate and strong intensity of the cytochemical reaction were found after both regimens of thawing. The percentage of spermatozoa manifesting strong intensity of the reaction was comparatively higher after thawing at 55 degrees C (31.8 +/- 2.06) than at 37 degrees C (23.7 +/- 1.41; P < 0.01). The thawing regimens were the factors that exerted influence on the morphofunctional state of frozen canine spermatozoa, irrespective of the cryoprotective extenders used, in the present study. Thus the optimal preservation of sperm viability was achieved by thawing at 55 degrees C for 5 sec.     

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     

棉花和香瓜的甘薯粉虱Bemisia tabaci (同翅目 ,粉虱科 )B生态型虫体大小和重量的田间调查(英文)

20 0 0和 2 0 0 1年在美国凤凰城和北达科塔州法哥城田间 ,调查棉花和香瓜上甘薯粉虱BemisiatabaciB生态型所有虫期虫体大小和重量。从若虫大小计算出若虫的体积。第一到第四龄晚期 ,若虫平均体积以指数方式增加。体积增加最快的是第三到第四龄早期。棉花上的若虫比香瓜上的宽 ,但是并不比较长。香瓜上第一到第四龄早期的若虫 ,最厚部位的腹部和背部厚度比例显著比棉花上的要高。两种寄主作物上的若虫从第一到第四龄发育期 ,腹部厚度平均增加将近 5 1倍 ,而背部厚度只增加 2 8倍。雌虫和雄虫从头顶到翅尖平均长度分别为 112 6和 95 3微米 ,重量为 39和 17微克。棉花和香瓜上的虫卵平均长 ,宽 ,重分别为 197微米 ,99微米 ,和0 8微克。未被寄生的蛹壳长 ,宽 ,重分别为 6 73微米 ,4 92微米和 1 2微克 ;被寄生的蛹壳为 6 6 5微米 ,4 5 2微米 ,和 3 6微克。棉花上未被寄生和被寄生的蛹壳比香瓜上的长 ,宽 ,和更重。