Dark adaptation processes in the amphibian rod

Rod dark adaptation in the amphibian retina appears to be due to three processes: 1. background adaptation, occurring immediately after the extinction of an adapting or bleaching light, 2. intermediate adaptation, that frequently lasts 30 min or more and 3. opsin adaptation, which in the isolated retina where regeneration of rhodopsin is insignificant, is observed as a permanent loss of sensitivity after the completion of intermediate adaptation. Intermediate adaptation is characterized by a linear relation between log threshold and the amount of retinal present, a similar relation is obtained between log threshold and the amount of rhodopsin bleached in opsin adaptation.These adaptation processes are discussed in terms of a model of the rod outer segment.Presented at the EMBO-Workshop on Transduction Mechanism of Photoreceptors, Jülich, Germany, October 4–8, 1976     

乌梅与乌梅炭的定性鉴别

通过性状、显微、理化、薄层色谱及紫外吸收光谱五个方面对乌梅和乌梅炭进行研究并加以比较。结果表明,乌梅和乌梅炭在性状、显微及薄层色谱方面区别不明显;但在pH值和紫外吸收光谱上有较大区别。     

Light Breaks and Fruit-Body Maturation in Coprinus congregatus: Dark Inhibitory and Dark Recovery Process

Experiments were conducted to better understand the inhibitoryeffect of lightduring the dark-induced process of fruit-bodysporulation of Coprinus congregatus Bull, ex Fr. Light-initiatedfruit-body primordia were subjected to different dark periodsinterrupted by a short blue light break at different times.The sporulating response depended on the duration of the darkperiod following the light break. For any inductive dark periodlonger than 3.5 h, a period of darkness lasting half as longas the inductive night completely inhibited fruit-body maturationwhen given after the light break (dark inhibitory process).Longer dark periods after the light break causedrecovery ofthe maximal sporulating response (dark recovery process). Theeffects of the dark inhibitory and the dark recovery processwere alternately reversible, the sporulating response dependingon the duration of darkness after the last light break. Studyof the time course of sporulation showed that a new dark-inducedprocess of fruit-body sporulation was initiated by the beginningof the dark period after the light break. (Received August 2, 1982; Accepted May 6, 1983)     

Dark clouds of contrast

Netherlands Heart Journal -