The Cell Adhesion Molecule Necl-4/CADM4 Serves as a Novel Regulator for Contact Inhibition of Cell Movement and Proliferation

Contact inhibition of cell movement and proliferation is critical for proper organogenesis and tissue remodeling. We show here a novel regulatory mechanism for this contact inhibition using cultured vascular endothelial cells. When the cells were confluently cultured, Necl-4 was up-regulated and localized at cell–cell contact sites where it cis-interacted with the vascular endothelial growth factor (VEGF) receptor. This interaction inhibited the tyrosine-phosphorylation of the VEGF receptor through protein-tyrosine phosphatase, non-receptor type 13 (PTPN13), eventually reducing cell movement and proliferation. When the cells were sparsely cultured, Necl-4 was down-regulated but accumulated at leading edges where it inhibited the activation of Rho-associated protein kinase through PTPN13, eventually facilitating the VEGF-induced activation of Rac1 and enhancing cell movement. Necl-4 further facilitated the activation of extracellular signal-regulated kinase 1/2, eventually enhancing cell proliferation. Thus, Necl-4 serves as a novel regulator for contact inhibition of cell movement and proliferation cooperatively with the VEGF receptor and PTPN13.     

Humans but Not Chimpanzees Vary Face-Scanning Patterns Depending on Contexts during Action Observation

Human and nonhuman primates comprehend the actions of other individuals by detecting social cues, including others’ goal-directed motor actions and faces. However, little is known about how this information is integrated with action understanding. Here, we present the ontogenetic and evolutionary foundations of this capacity by comparing face-scanning patterns of chimpanzees and humans as they viewed goal-directed human actions within contexts that differ in whether or not the predicted goal is achieved. Human adults and children attend to the actor’s face during action sequences, and this tendency is particularly pronounced in adults when observing that the predicted goal is not achieved. Chimpanzees rarely attend to the actor’s face during the goal-directed action, regardless of whether the predicted action goal is achieved or not. These results suggest that in humans, but not chimpanzees, attention to actor’s faces conveying referential information toward the target object indicates the process of observers making inferences about the intentionality of an action. Furthermore, this remarkable predisposition to observe others’ actions by integrating the prediction of action goals and the actor’s intention is developmentally acquired.     

Correction to: Herding mechanisms to maintain the cohesion of a harem group: two interaction phases during herding

Journal of Ethology - The article Herding mechanisms to maintain the cohesion of a harem group.     

Capability of intensity discrimination in multiple receptor model of insect taste

A simple model in which one CNS taste neuron integrates inputsfrom multiple peripheral receptors is introduced in order toinvestigate the mechanism of acute intensity taste discriminationin flies. Information theory is applied to evaluate the acuteability of discrimination provided by the model. The presentanalysis is carried out under two statistical conditions concerningthe uncertainty of receptor response. Based on experimentaldata obtained by Smith et al. (1983), we estimate the mutualinformation entropy of the model. The numerical results obtainedhere indicate that the uncertainty observed in a single receptorresponse is dramatically reduced by the central integration.Furthermore, each of the eleven stimulus intensity levels experimentallyapplied by Smith et al., can be discriminated completely byintegrating the responses of the realistic number of receptors(33–212). Such a great improvement of the differentialsensitivity in the model resolves the discrepancy between thelow differential sensitivity of single sugar receptors (Smithet al., 1983) and the high sensitivity obtained in the feedingbehavior (Dethier and Rhoades, 1954; Dethier and Bowdan, 1984)of the blowfly.     

Evolution of a predator-prey Volterra-Lotka ecosystem with saturation effect

This paper has studied the evolution of a predator-prey Volterra-Lotka ecosystem with saturation effect for the general case where both predator and prey evolve. We have interesting results under the evolutional condition, as follows: (1) the predator population and the ratio of predator to prey populations increase; (2) the parameters of the prey drift in the direction of increasing multiplication rate and saturation level, while the parameters of the predator drift in the direction of decreasing death rate.     

Yolk Phosphoprotein Metabolism during Early Development of the Fish, Oryzias latipes

Changes in yolk phosphoproteins of Oryzias latipes embryos during early development were examined by electrophoresis. Four phosphoproteins were identified in the yolk of blastulae by polyacrylamide gel electrophoresis. Two of them were high molecular weight phosphoproteins containing 0.7% (w/w) phosphorus and with similar amino acid compositions to that of vitellogenin. The other two were low molecular weight phosphoproteins, characterized by high contents of phosphorus [12.2% (w/w)] and serine (44.8 mole%) and low contents of aromatic amino acid residues. From these characteristics, together with their behaviors on DEAE-cellulose chromatography and electrophoresis and low stainability with dyes, the latter two were concluded to be phosvitins. These phosvitins were isolated and partially characterized.
The yolk phosphoproteins, especially the phosvitins, were degraded, their amounts in embryos decreased throughout early development. Studies on the mechanism of endogenous phosphoprotein degradation strongly suggested the participation of some protease(s) that was precipitated on centrifugation of the egg homogenate at 14,000 × g for 10 min.