Macrocortin: a polypeptide causing the anti-phospholipase effect of glucocorticoids

Anti-inflammatory glucocorticoids inhibit prostaglandin (PG) biosynthesis by preventing arachidonic acid release from phospholipids rather than inhibiting the cyclooxygenase. As in other cells, this steroid action depends on receptor occupation and de novo protein/RNA biosynthesis. We have previously shown in guinea pig perfused lungs and rat peritoneal leukocytes that the effect of steroids in PG generation is mediated by an uncharacterized 'second messenger'. Now, we report that this factor (which we have named 'macrocortin') is an intracellular polypeptide whose release and synthesis are stimulated by steroids. Macrocortin derived from rat peritoneal leukocytes is very similar to that released from guinea pig lungs.     

Formation of 5-hydroxytryptophol by blood platelets after thrombin and reserpine

Zusammenfassung In isolierten Blutplättchen von Kaninchen bewirkt Thrombin rasche und hochgradige Freisetzung von unverändertem 5-Hydroxytryptamin, welches durch weitere Inkubation sekundär teilweise zu 5-Hydroxytryptophol und 5-Hydroxyindolessigsäure umgewandelt wird. Nach Reserpin scheint hingegen ein Teil des 5-Hydroxytryptamins bereits bei seiner Freisetzung zu diesen Metaboliten abgebaut zu werden.     

Electron diffraction and electron microscopy studies on the crystalline component of enamel of theOdontaspis (selachii)

Résumé L'auteur constate que dans la dent du Requin du genreOdontaspis l'ultrastucture de la substance qui recouvre la dentine est morphologiquement très semblable à celle de l'émail de la dent humaine. Par diffraction électronique le composant cristallin de l'émail du Requin a été déterminé comme étant del'apatite. Ces résultats montrent que le revêtement externe de la dent d'Odontaspis peut être considéré comme un véritable émail.     

Endogenous neurosteroids regulate GABAA receptors through two discrete transmembrane sites

Inhibitory neurotransmission mediated by GABA(A) receptors can be modulated by the endogenous neurosteroids, allopregnanolone and tetrahydro-deoxycorticosterone. Neurosteroids are synthesized de novo in the brain during stress, pregnancyand after ethanol consumption, and disrupted steroid regulation of GABAergic transmission is strongly implicated in several debilitating conditions such as panic disorder, major depression, schizophrenia, alcohol dependence and catamenial epilepsy. Determining how neurosteroids interact with the GABA(A) receptor is a prerequisite for understanding their physiological and pathophysiological roles in the brain. Here we identify two discrete binding sites in the receptor's transmembrane domains that mediate the potentiating and direct activation effects of neurosteroids. They potentiate GABA responses from a cavity formed by the alpha-subunit transmembrane domains, whereas direct receptor activation is initiated by interfacial residues between alpha and beta subunits and is enhanced by steroid binding to the potentiation site. Thus, significant receptor activation by neurosteroids relies on occupancy of both the activation and potentiation sites. These sites are highly conserved throughout the GABA(A )receptor family, and their identification provides a unique opportunity for the development of new therapeutic, neurosteroid-based ligands and transgenic disease models of neurosteroid dysfunction.     

Capybaras (Rodentia: Cavidae) in highlands: environmental variables related to distribution,and herbivory effects on a common plant species

The capybara Hydrochoerus hydrochaeris is one of the largest and most widely distributed herbivores in the Neotropical lowlands. However, as yet, there are no records of its occurrence in highland environments. Our aim was to evaluate the environmental variables related to the capybara’s distribution and monitor the effects of its herbivory on the individuals and on the reproductive phenology of A. polyanthus, a common and important plant species of the high-altitude grasslands. Our results show that capybaras frequently occur in the high-altitude grasslands along the Campo Belo River, but they avoid waterlogged areas, occurring more frequently on the dry rocky areas. Capybara herbivory affected the number of A. polyanthus rosettes in flower, leading to the presence of inflorescence formation anomalies. High-altitude grasslands apparently provide capybaras with the three main components (food, shelter and water) required for their occurrence. However, although they seem to present a seasonal feeding strategy, which also happens in lowlands, their avoidance of the waterlogged areas suggests that in highlands the species may present different environmental preferences from those presented in lowlands. In addition, the impact of capybaras’ herbivory on A. polyanthus individuals indicates the potential impact that capybaras can represent on the plant community of the high-altitude grasslands. This appears to be a great opportunity to study the effect of the arrival of a large herbivore in a new environment and possible impacts on plant assemblages.     

电磁环境数据场多频段绘制算法

针对现有电磁环境绘制研究中未考虑频段信息的情况,提出了一种多频段电磁环境绘制算法。基于光线投射算法实现,对传递函数进行了多频段设计,各频段颜色可以交互设置,同时定义了频段颜色增强因子,能够提高不同频段的颜色对比效果。最后,在统一计算设备架构下并行实现本算法,完成了实时交互的多频段电磁环境绘制。实验证明该算法能够方便、有效的展示电磁环境的频段信息,同时用户可以交互控制绘制及频段对比结果,便于观察和理解电磁环境。