Boden – ein unterschätzter Lebensraum

Soil – an underestimated biotope The soil is a biotope with high species abundances and richness. It is, furthermore, a location where important ecosystem services are realized. Recent research projects on the origin and development of soil animal communities, on the heterogeneous interactions within the soil nutrient net and the distribution of soil animals show the different ecological traits and adaptabilities of the world beneath our feet. So research contributes to maintain the eco‐resource of soil and its sustainable use.     

L’imagerie TEP-traceurs des plaques amyloïdes : le point de vue du clinicien

The purpose of this article is to summarize the main elements of clinician point of view concerning the contribution of amyloid neuroimaging in the diagnostic approach of the Alzheimer's disease. The main pathological characteristics of the Alzheimer's disease are established by two types of protein aggregates: the extracellular plaques (containing Aβ aggregates) and neurofibrillary tangles (composed of aggregates of tau-protein). At present, the use of biomarkers is more and more included in the diagnostic approach of Alzheimer's disease. The possibility to highlight in vivo cortical amyloid deposits through the amyloid neuroimaging can allow the realization of an earlier diagnosis. However, the amyloid imaging is a “physiopathological” biomarker and is not correlated with the clinical evaluation. It is still difficult to differentiate the Alzheimer's disease of the other neurodegenerative diseases.     

内含肽介导的蛋白连接技术及其应用

内含肽介导的蛋白质剪接是一种自发的翻译后事件,内含肽可介导其自身从前体蛋白上切除,同时将其两侧的外显肽连接起来.在过去10多年中,基于蛋白质剪接原理发展出的蛋白连接技术被广泛的用于蛋白质工程的研究中.这些技术打破了化学合成方法中对目标物大小的限制,有助于化学和生物学的研究.针对近年由蛋白质连接演化出来的新技术及其应用做简要的阐述.     

小反刍兽疫研究概况

小反刍兽疫是严重危害山羊和绵羊等家畜的A类动物传染病,目前该病已经给我国养羊业造成了巨大的威胁。近年来,国内外学者对该病开展了许多研究工作,本文从病原学、流行病学、临床症状、发病机理、病理变化、诊断、防控措施等几个方面对该病研究概况进行了综述,为该病的有效防控提供有益的参考。     

The stabilizability of a controlled system describing the dynamics of a fishery

This work presents two stock-effort dynamical models describing the evolution of a fish population growing and moving between two fishing zones, on which it is harvested by a fishing fleet, distributed on the two zones. The first model corresponds to the case of constant displacement rates of the fishing effort, and the second one to fish stock-dependent displacement rates. In equations of the fishing efforts, a control function is introduced as the proportion of the revenue to be invested, for each fleet. The stabilizability analysis of the aggregated model, in the neighborhood of the equilibrium point, enables the determination of a Lyapunov function, which ensures the existence of a stabilizing discontinuous feedback for this model. This enables us to control the system and to lead, in an uniform way, any solution of this system towards this desired equilibrium point.     

Können Tiere zählen?

The “magical” number four We know already since more than 140 years that humans have the inborn ability to recognize only up to four objects correctly if counting is strictly inhibited. Many vertebrates and the honeybee workers can remember up to four objects albeit they are unable to count. This inborn numerical competence common to humans and animals raises interesting questions concerning the purpose and the evolution of this ability. The “magical” number four is obviously a neurological, historical and mythological enigma.     

家蚕近交系遗传纯度的RAPD检测

目的分析家蚕近交系IS-c108A的遗传纯度,为家蚕实验动物化的培育工作提供指导。方法应用经过筛选的20条随机引物对家蚕近交系IS-c108A(F10)的3个蛾区各30个个体和该近交系的亲本系统c108、对照实用化品种871各30个个体的基因组DNA进行RAPD扩增,计算个体间和蛾区间的相似系数及遗传距离。结果家蚕近交系IS-c108A(F10)的3个蛾区内的多态性带频率分别为1.807%、1.841%、1.841%,平均为1.830%;起点亲本c108个体间多态性带频率为7.207%,对照品种871个体间的多态性带频率为7.08%;而近交系IS-c108A与c108之间的多态性带频率为49.20%,c108和871品种之间的多态性带频率为58.33%。家蚕近交系IS-c108A10的3个蛾区内个体之间遗传相似系数的平均值分别为0.99581、0.99555、0.99551,总平均为0.99562。结论家蚕近交系IS-c108A(F10)已具有较高的遗传纯合度,家蚕具有易于获得高纯的有利条件。     

Physico-chemical investigation of the mode of binding of the alkaloids 5,6-dihydroflavopereirine and sempervirine with DNA

The mode of binding of 5,6-dihydroflavopereirine and sempervirine to DNA has been investigated by absorption spectrophotometry, circular and electric linear dichroism, fluorescence and fluorescence polarization, viscosity increase of sonicated linear DNA and circular DNA unwinding. Although the spectroscopic properties of both compounds bound to DNA resembled those reported in our previous study of DNA complexes with two other alkaloids, and observed with planar intercalating compounds, only sempervirine was able to unwind circular DNA. The latter drug however showed signs characteristic of aggregation at the surface of the polyion. The differences between the behaviours of the four alkaloids so far investigated by us are interpreted on the basis of different extent of penetration of the chromophore ring into the DNA helix.     

Effect of ouabain on the lactogenic action of prolactin and on the level of mammary prolactin receptors

Ouabain added to the culture medium of rabbit mammary gland inhibits prolactin action on the initiation of lactose and casein synthesis. The degree of inhibition is a function of the ouabain concentration in the medium. Likewise, ouabain blocks the accumulation of casein mRNA supported by prolactin. In addition, ouabain provokes a rapid disappearance of prolactin receptors. Conversely prolactin keeps its capacity to enhance the concentration of casein mRNA and the parallel casein synthesis when K+ ions are totally absent from the culture medium. These results suggest that although prolactin induces a modification of the K+/Na+ ratio in the mammary cell and ouabain prevents this effect of prolactin, the inhibitory action of ouabain on lactogenesis can be explained essentially by its effect on the hormone receptors.