Functionality of wrapping defects in soluble proteins: what cannot be kept dry must be conserved

Soluble proteins preserve their structure only if a sufficient number of non-polar groups are clustered around the backbone hydrogen bonds, protecting them from water attack. When these bonds are not properly wrapped or dehydrated intramolecularly, structural integrity can be preserved through binding partnerships. This is because insufficiently wrapped hydrogen bonds are inherently adhesive and become better shielded upon protein-ligand association. Thus, we postulate that deficiently wrapped hydrogen bonds are functionally relevant. Two findings that support this conjecture are: (a) there is a statistically relevant linear correlation between the number of defects in a folding domain and its proteomic connectivity, obtained from large-scale two-hybrid experiments; (b) the residues paired by under-wrapped hydrogen bonds are highly conserved. The high mutational sensitivity of under-wrapped regions can be rationalized, since their structural integrity relies on their propensity to behave as binding sites, in turn, a consequence of their adhesiveness. Thus, the regions in soluble protein structure that cannot be kept dry in water tend to be conserved.     

模拟氮沉降对荆条灌木“肥岛”土壤养分的影响

氮沉降的增加,可能会对土壤养分造成更为显著的影响,目前关于大气氮沉降对植物"肥岛"效应中土壤养分的影响鲜有报道。于河南省太行山南麓地区,以NH_4NO_3为供施氮源,按土层深度采集土样,以模拟氮沉降方法(3个水平,无氮CK、低氮2g N m~(-2)a~(-1)处理、中氮12g N m~(-2)a~(-1)处理和高氮24g N m~(-2)a~(-1)处理),分析了氮沉降对太行山荆条灌木(Vitex negundo L.var.)"肥岛"土壤中有机质、全氮和速效磷含量的影响。结果表明:灌木"肥岛"中全氮和速效磷含量,总体表现出随氮沉降量增长而增加的趋势;氮沉降显著增加了土壤表层有机质、氮、磷的含量;高氮沉降与CK相比引起的各土层间养分差异更显著;随着氮沉降水平的增加,冠幅内外和土层间养分差异增大,土壤养分的增长率随之加大;氮沉降在一定程度内加剧了"肥岛"的富集效应,且氮沉降量越大,这种富集效应越显著。这些研究结果可为研究灌木"肥岛"对外源氮的响应机制及保育作用提供参考。     

Dream incorporation of video-game play as a function of interactivity and fidelity.

Video-game play offers the opportunity to investigate the continuity hypothesis. Using interactive video games rather than passive films as a controlled manipulation allows for an engaging presleep experience. Several researchers have successfully used video games to investigate dream incorporation. In this study, interactivity and fidelity were the independent measures that manipulated immersion in a commercially available video game. Interactivity was either passive or active, whereas fidelity was high-screen resolution and stereophonic headset audio versus low. The highest dream incorporation in the high-fidelity–high-interactivity condition was expected. Incorporation was assessed by participant self-report and judges' evaluations. The independent variable of fidelity was especially strong in both the manipulation and the subsequent dream incorporation for self-report. Interactivity became the dominant variable when viewed from the judges' perspectives. The effects of demand characteristics and emotionality were also considered. (PsycINFO Database Record (c) 2011 APA, all rights reserved)