The evolution of signal form: Effects of learned versus inherited recognition

Organisms can learn by individual experience to recognize relevant stimuli in the environment or they can genetically inherit this ability from their parents. Here, we ask how these two modes of acquisition affect signal evolution, focusing in particular on the exaggeration and cost of signals. We argue first, that faster learning by individual receivers cannot be a driving force for the evolution of exaggerated and costly signals unless signal senders are related or the same receiver and sender meet repeatedly. We argue instead that biases in receivers’ recognition mechanisms can promote the evolution of costly exaggeration in signals. We provide support for this hypothesis by simulating coevolution between senders and receivers, using artificial neural networks as a model of receivers’ recognition mechanisms. We analyse the joint effects of receiver biases, signal cost and mode of acquisition, investigating the circumstances under which learned recognition gives rise to more exaggerated signals than inherited recognition. We conclude the paper by discussing the relevance of our results to a number of biological scenarios

Japanese version of the family dermatology life quality index: translation and validation

Skin conditions affect the quality of life (QoL) of patients and their family. To assess family members' QoL, a questionnaire uniquely designed for family members is necessary. We translated the Family Dermatology Life Quality Index (FDLQI), originally created and validated by Basra et al., into Japanese, and evaluated its reliability and validity. For psychometric evaluations, 150 dermatology patients and their family members were included. The Japanese version of the FDLQI showed high test–retest reliability (intraclass correlation coefficient = 0.95) and internal consistency reliability (Cronbach's alpha = 0.86). FDLQI scores significantly correlated with DLQI scores (r = 0.58, P < 0.01, Spearman's rho) and global question (GQ) which measured the patient's skin condition on a visual analog scale (r = 0.36, P < 0.01). Family members of patients with inflammatory skin diseases showed higher FDLQI scores than those with isolated lesions, but the difference was not statistically significant (P = 0.062, Mann–Whitney U-test). Responsiveness to change was demonstrated in a group in which the patient's skin condition was assessed as improved (n = 37, r = 0.46, P < 0.01) but not in that in which it became worse. The difference of the change between the two groups was statistically significant (P < 0.01). Additionally, the change in FDLQI scores and GQ were significantly correlated (r = 0.40, P < 0.01). Exploratory factor analysis suggested essential unidimensionality of the instrument. We showed acceptable validity and responsiveness of this Japanese version of FDLQI. Further clinical epidemiological studies are required to confirm this

An efficient synthesis of procyanidins. Rare earth metal Lewis acid catalyzed equimolar condensation of catechin and epicatechin

ArticleTETRAHEDRON LETTERS. 48(33): 5891-5894 (2007)journal articl

Success of a suicidal defense strategy against infection in a structured habitat

Pathogen infection often leads to the expression of virulence and host death when the host-pathogen symbiosis seems more beneficial for the pathogen. Previously proposed explanations have focused on the pathogen's side. In this work, we tested a hypothesis focused on the host strategy. If a member of a host population dies immediately upon infection aborting pathogen reproduction, it can protect the host population from secondary infections. We tested this "Suicidal Defense Against Infection" (SDAI) hypothesis by developing an experimental infection system that involves a huge number of bacteria as hosts and their virus as pathogen, which is linked to modeling and simulation. Our experiments and simulations demonstrate that a population with SDAI strategy is successful in the presence of spatial structure but fails in its absence. The infection results in emergence of pathogen mutants not inducing the host suicide in addition to host mutants resistant to the pathogen

Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation

Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2–10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2–6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement