Publications (35)99.57 Total impact
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Article: Asymmetry in Facial Expressions as a Function of Social Skills
IEICE Transactions on Information and Systems 01/2013; E96-D(3):507-513. · 0.18 Impact Factor -
Dataset: JEPHPP
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Article: Low activation and fast inactivation of transducin in carp cones.
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ABSTRACT: Cone photoreceptors show lower light sensitivity and briefer light responses than rod photoreceptors. Light detection signal in these cells is amplified through a phototransduction cascade. The first step of amplification in the cascade is the activation of a GTP-binding protein, transducin (Tr), by light-activated visual pigment (R*). We quantified transducin activation by measuring the binding of GTPγS in purified carp rod and cone membrane preparations with use of a rapid quench apparatus, and found that transducin activation by an R* molecule is ~5 times less efficient in cones than in rods. Transducin activation terminated in less than 1 sec in cones, more quickly than in rods. The rate of GTP hydrolysis in Tr*, thus the rate of Tr* inactivation was ~25 times higher in cones than in rods. This faster inactivation of Tr* ensures briefer light responses in cones. Expression level of RGS9 was found to be ~20 times higher in cones than in rods, which explains higher GTP hydrolytic activity and thus faster Tr* inactivation in cones than in rods. Although carp rods and cones express rod- or cone-versions of visual pigment and transducin, these molecules themselves do not seem to induce the differences significantly in the transducin activation and Tr* inactivation in rods and cones. Instead, the differences seem to be brought about in a rod or cone cell-type specific manner.Journal of Biological Chemistry 10/2012; · 4.77 Impact Factor -
Article: Explaining the functional differences of rods versus cones
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ABSTRACT: Our visual sensation is mediated by two types of photoreceptors, rods and cones. Both respond to light electrically. Rods are highly light-sensitive but cones are not. Because of this sensitivity difference, rods mediate night vision and cones mediate daylight vision. While a response to a brief light flash is rather slow in rods, it is brief in cones. These rod and cone differences in their light sensitivity and the response time course arise in the differences in the reactions in the enzyme cascade to evoke light responses in these cells. This cascade (phototransduction cascade) in rods is now rather well understood at the molecular level in a quantitative way. In cones, similar cascade has been known to be present. However, details are not known yet because it was difficult to obtain purified cones in an amount large enough to study these issues biochemically. Fortunately, we succeeded in the purification of enough amounts of cones from the retina of carp (Cyprinus carpio), which enables us to compare the qualitative and quantitative differences in the phototransduction cascade between rods and cones. The results so far we obtained explain lower light sensitivity and briefer light responses in cones than in rods. Furthermore, an additional difference between rods and cones was found in the retinoid metabolism. This reaction, specifically found in cones, ensures effective regeneration of visual pigment so that cones can operate even under very bright light.WIREs Membrane Transport and signaling. 01/2012; -
Article: Multiple mechanisms in the perception of face gender: Effect of sex-irrelevant features.
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ABSTRACT: Effects of sex-relevant and sex-irrelevant facial features on the evaluation of facial gender were investigated. Participants rated masculinity of 48 male facial photographs and femininity of 48 female facial photographs. Eighty feature points were measured on each of the facial photographs. Using a generalized Procrustes analysis, facial shapes were converted into multidimensional vectors, with the average face as a starting point. Each vector was decomposed into a sex-relevant subvector and a sex-irrelevant subvector which were, respectively, parallel and orthogonal to the main male-female axis. Principal components analysis (PCA) was performed on the sex-irrelevant subvectors. One principal component was negatively correlated with both perceived masculinity and femininity, and another was correlated only with femininity, though both components were orthogonal to the male-female dimension (and thus by definition sex-irrelevant). These results indicate that evaluation of facial gender depends on sex-irrelevant as well as sex-relevant facial features.Journal of Experimental Psychology Human Perception & Performance 06/2011; 37(3):626-33. · 3.06 Impact Factor -
Article: Larger inhibition of visual pigment kinase in cones than in rods.
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ABSTRACT: In the carp retina, visual pigment kinase, GRK1 (G-protein coupled receptor kinase 1) in rods and GRK7 in cones, is inhibited by a photoreceptor neuronal Ca(2+)-sensor protein, S-modulin (or recoverin) in rods and visinin (formerly named s26) in cones. Here, we compared Ca(2+)-dependent inhibition of GRK1 by S-modulin and that of GRK7 by visinin. First, the concentrations of S-modulin and visinin in the outer segment were estimated: the concentration of visinin (1.2 mM) was 20 times higher than that of S-modulin (53 μM). Based on the determined concentrations of the Ca(2+)-sensor proteins and the known dark Ca(2+) concentrations, we estimated that in situ Ca(2+)-dependent inhibition on GRK in cones would be 2.5 times higher than that in rods at the Ca(2+) concentration in the dark. Because GRK activity is approximately 100 times higher in cones than in rods [Proc. Natl Acad. Sci. USA 102 (2005) 21359], the range of Ca(2+)-dependent inhibition on GRK activity is more than 100 times wider in cones than in rods. The inhibitory effects of S-modulin and visinin on photoreceptor GRKs were indistinguishable, although these Ca(2+)-sensor proteins are expressed in a cell-type specific manner. The inhibition by these Ca(2+)-sensor proteins was slightly higher on GRK7 than GRK1 probably because of a characteristic specific to GRK7.Journal of Neurochemistry 10/2010; 115(1):259-68. · 4.06 Impact Factor -
Article: Inhibitory action of Xenopus dicalcin on sperm-egg interaction during fertilization.
Developmental Biology 08/2010; 344(1):511-512. · 4.07 Impact Factor -
Article: Dicalcin inhibits fertilization through its binding to a glycoprotein in the egg envelope in Xenopus laevis.
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ABSTRACT: Fertilization comprises oligosaccharide-mediated sperm-egg interactions, including sperm binding to an extracellular egg envelope, sperm penetration through the envelope, and fusion with an egg plasma membrane. We show that Xenopus dicalcin, an S100-like Ca(2+)-binding protein, present in the extracellular egg envelope (vitelline envelope (VE)), is a suppressive mediator of sperm-egg interaction. Preincubation with specific antibody greatly increased the efficiency of in vitro fertilization, whereas prior application of exogenous dicalcin substantially inhibited fertilization as well as sperm binding to an egg and in vitro sperm penetration through the VE protein layer. Dicalcin showed binding to protein cores of gp41 and gp37, constituents of VE, in a Ca(2+)-dependent manner and increased in vivo reactivity of VE with a lectin, Ricinus communis agglutinin I, which was accounted for by increased binding ability of gp41 to the lectin and greater exposure of gp41 to an external environment. Our findings strongly suggest that dicalcin regulates the distribution of oligosaccharides within the VE through its binding to the protein core of gp41, probably by modulating configuration of oligosaccharides on gp41 and the three-dimensional structure of VE framework, and thereby plays a pivotal role in sperm-egg interactions during fertilization.Journal of Biological Chemistry 03/2010; 285(20):15627-36. · 4.77 Impact Factor -
Article: High cGMP synthetic activity in carp cones.
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ABSTRACT: Cones show briefer light responses than rods and do not saturate even under very bright light. Using purified rod and cone homogenates, we measured the activity of guanylate cyclase (GC), an enzyme responsible for cGMP synthesis and therefore recovery of a light response. The basal GC activity was 36 times higher in cones than in rods: It was mainly caused by higher expression levels of GC in cones (GC-C) than in rods (GC-R). With identification and quantification of GC-activating protein (GCAP) subtypes expressed in rods and cones together with determination of kinetic parameters of GC activation in the presence and absence of GCAP, we estimated the in situ GC activity in rods and cones at low and high Ca(2+) concentrations. It was revealed that the GC activity would be >10 times higher in cones than in rods in both the dark-adapted and the light-adapted states. Electrophysiological estimation of the GC activity measured in the truncated preparations of rod and cone outer segments gave consistent results. Our estimation of the in situ GC activity reasonably explained the rapid recovery and nonsaturating behavior of cone light responses.Proceedings of the National Academy of Sciences 06/2009; 106(28):11788-93. · 9.68 Impact Factor -
Article: Averageness or symmetry: which is more important for facial attractiveness?
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ABSTRACT: Effects of averageness and symmetry on the judgment of facial attractiveness were investigated using a generalized Procrustes method and multiple regression analyses. Participants (n=114) rated attractiveness of 96 photographs of faces with neutral expressions. Through a generalized Procrustes method, the faces and their mirror-reversed versions were represented as points on a hyperplane. Both averageness and symmetry of each individual were defined as distances on the plane. A multiple regression analysis was performed to examine the effect of symmetry and averageness for each gender. For male faces, both symmetry and averageness affected attractiveness ratings positively , and there was no difference between the effects of averageness and symmetry. On the other hand, for female faces only averageness affected attractiveness, whereas symmetry did not. However, these effects were not large.Acta psychologica 05/2009; 131(2):136-42. · 2.19 Impact Factor -
Article: Effect of averageness and sexual dimorphism on the judgment of facial attractiveness.
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ABSTRACT: Effect of sexual dimorphism and averageness on the judgment of facial attractiveness was investigated. Participants (n=114) rated attractiveness of 96 facial photographs with neutral expressions. Principal component analyses were conducted on 80 facial feature points standardized via the generalized Procrustes method. Local regression analysis was used to obtain the distribution of attractiveness evaluations for the first two principal components. The distribution of facial attractiveness of each sex was approximately line-symmetrical, and each axis of the symmetry passed through average male and female faces. These results suggest that sexual dimorphism and averageness independently influence facial attractiveness.Vision research 04/2009; 49(8):862-9. · 2.29 Impact Factor -
Article: S100-annexin complexes--biology of conditional association.
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ABSTRACT: S100 proteins and annexins both constitute groups of Ca2+-binding proteins, each of which comprises more than 10 members. S100 proteins are small, dimeric, EF-hand-type Ca2+-binding proteins that exert both intracellular and extracellular functions. Within the cells, S100 proteins regulate various reactions, including phosphorylation, in response to changes in the intracellular Ca2+ concentration. Although S100 proteins are known to be associated with many diseases, exact pathological contributions have not been proven in detail. Annexins are non-EF-hand-type Ca2+-binding proteins that exhibit Ca2+-dependent binding to phospholipids and membranes in various tissues. Annexins bring different membranes into proximity and assist them to fuse, and therefore are believed to play a role in membrane trafficking and organization. Several S100 proteins and annexins are known to interact with each other in either a Ca2+-dependent or Ca2+-independent manner, and form complexes that exhibit biological activities. This review focuses on the interaction between S100 proteins and annexins, and the possible biological roles of these complexes. Recent studies have shown that S100-annexin complexes have a role in the differentiation of gonad cells and neurological disorders, such as depression. These complexes regulate the organization of membranes and vesicles, and thereby may participate in the appropriate disposition of membrane-associated proteins, including ion channels and/or receptors.FEBS Journal 10/2008; 275(20):4945-55. · 3.79 Impact Factor -
Article: Highly efficient retinal metabolism in cones.
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ABSTRACT: After bleaching of visual pigment in vertebrate photoreceptors, all-trans retinal is reduced to all-trans retinol by retinol dehydrogenases (RDHs). We investigated this reaction in purified carp rods and cones, and we found that the reducing activity toward all-trans retinal in the outer segment (OS) of cones is >30 times higher than that of rods. The high activity of RDHs was attributed to high content of RDH8 in cones. In the inner segment (IS) in both rods and cones, RDH8L2 and RDH13 were found to be the major enzymes among RDH family proteins. We further found a previously undescribed and effective pathway to convert 11-cis retinol to 11-cis retinal in cones: this oxidative conversion did not require NADP(+) and instead was coupled with reduction of all-trans retinal to all-trans retinol. The activity was >50 times effective than the oxidizing activity of RDHs that require NADP(+). These highly effective reactions of removal of all-trans retinal by RDH8 and production of 11-cis retinal by the coupling reaction are probably the underlying mechanisms that ensure effective visual pigment regeneration in cones that function under much brighter light conditions than rods.Proceedings of the National Academy of Sciences 10/2008; 105(41):16051-6. · 9.68 Impact Factor -
Article: Rod and cone photoreceptors: molecular basis of the difference in their physiology.
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ABSTRACT: Vertebrate retinal photoreceptors consist of two types of cells, the rods and cones. Rods are highly light-sensitive but their flash response time course is slow, so that they can detect a single photon in the dark but are not good at detecting an object moving quickly. Cones are less light-sensitive and their flash response time course is fast, so that cones mediate daylight vision and are more suitable to detect a moving object than rods. The phototransduction mechanism was virtually known by the mid 80s, and detailed mechanisms of the generation of a light response are now understood in a highly quantitative manner at the molecular level. However, most of these studies were performed in rods, but not in cones. Therefore, the mechanisms of low light-sensitivity or fast flash response time course in cones have not been known. The major reason for this slow progress in the study of cone phototransduction was due to the inability of getting a large quantity of purified cones to study them biochemically. We succeeded in its purification using carp retina, and have shown that each step responsible for generation of a light response is less effective in cones and that the reactions responsible for termination of a light response are faster in cones. Based on these findings, we speculated a possible mechanism of evolution of rods that diverged from cones.Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 09/2008; 150(4):369-77. · 2.20 Impact Factor -
Article: Smiling emphasizes perceived distinctiveness of faces.
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ABSTRACT: In this study, 114 Japanese observers (56 men and 58 women) rated the distinctiveness of 48 neutral faces and 48 smiling faces. Analysis showed smiling faces were rated as significantly more distinctive than neutral ones. Greater perceived distinctiveness provides an explanation for previous results that smiling faces are better remembered than faces with neutral expressions.Perceptual and Motor Skills 09/2008; 107(1):119-20. · 0.49 Impact Factor -
Article: Amino acid residues in GRK1/GRK7 responsible for interaction with S-modulin/recoverin.
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ABSTRACT: GRK1 is a visual pigment kinase in rods and is essential for inactivation of light-activated rhodopsin. The GRK1 activity is inhibited by binding of the Ca(2+)-bound form of S-modulin/recoverin. We previously identified the S-modulin/recoverin site to interact with GRK1. In the present study, we identified its counterpart in GRK1. We synthesized 29 of GRK1 or GRK7 partial peptides that cover the entire sequence of GRK1/GRK7, and examined whether these peptides inhibit S-modulin/recoverin activity most probably by preoccupying the binding site for GRK1. The inhibition was the greatest with the N-terminal peptide (p1, aa 3-23 in GRK7). On mutation of each of eight amino acid residues highly conserved in the p1 region of more than 10 orthologs, the inhibition was significantly reduced in the mutation of Leu(6), Asn(12) and Tyr(15). We further examined the binding of the peptides, including mutated ones, to S-modulin/recoverin with a resonance mirror biosensor. The binding correlated well with the degree of the inhibition by a peptide. The inhibition, therefore, seemed to be due to a direct binding of the kinase peptide to the binding site of active S-modulin/recoverin. A GRK1 region close to its C-terminus also seemed to be the binding site for S-modulin/recoverin.Photochemistry and Photobiology 03/2008; 84(4):823-30. · 2.41 Impact Factor -
Article: Identification of differentially expressed genes in carp rods and cones.
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ABSTRACT: Rods and cones differ in their photoresponse characteristics, morphology, and susceptibilities to certain diseases. To contribute to the studies at the molecular level of these differences, we tried to identify genes expressed preferentially in rods or cones. From purified carp rods and cones, we extracted their RNA and obtained corresponding cDNA pools (rod cDNA and cone cDNA). We employed the suppression subtractive hybridization method to identify the genes expressed preferentially in rods or cones. Cone cDNA was subtracted from rod cDNA to obtain cDNA, which ideally contained cDNA expressed preferentially in rods (R/c cDNA). Similarly, rod cDNA was subtracted from cone cDNA to obtain C/r cDNA. With differential array screening, we screened candidate genes that were expressed mainly or exclusively in rods or cones. The nucleotide sequences of the positive genes were determined. In some of them, their mRNA localizations were confirmed by in situ hybridization. R/c cDNA contained genes already known to code rod specific proteins, such as cGMP gated channel, transducin beta1, and rhodopsin. In sharp contrast, C/r cDNA contained genes that code proteins of which functions are mostly unknown. Among them, N-myc downregulated gene 1-like (NDRG1L) and aryl hydrocarbon receptor 2 (AhR2) were most abundant, and by in situ hybridization, they were proven to be expressed specifically in cones. Using purified rods and cones, we identified mRNAs expressed preferentially in rods or cones. Of particular interest is the specific expression of NDRG1L and AhR2 in cones.Molecular vision 02/2008; 14:358-69. · 2.20 Impact Factor -
Article: Smiling reduces masculinity: principal component analysis applied to facial images.
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ABSTRACT: We examined the effect of facial expression on the assignment of gender to facial images. A computational analysis of the facial images was applied to examine whether physical aspects of the face itself induced this effect. Thirty-six observers rated the degree of masculinity of the faces of 48 men, and the degree of femininity of the faces of 48 women. Half of the faces had a neutral facial expression, and the other half was smiling. Smiling significantly reduced the perceived masculinity of men's faces, especially for male observers, whereas no effect of smiling on femininity ratings was obtained for women's faces. A principal component analysis was conducted on the matrix of pixel luminance values for each facial image x all the images. The third principle component explained a relatively high proportion of the variance of both facial expressions and gender of face. These results suggest that the effect of smiling on the assignment of gender is caused, at least in part, by the physical relationship between facial expression and face gender.Perception 02/2008; 37(11):1637-48. · 1.31 Impact Factor -
Article: Cloning and characterization of Xenopus dicalcin, a novel S100-like calcium-binding protein in Xenopus eggs.
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ABSTRACT: To contribute to the study of the calcium-signaling mechanism of egg, we cloned and characterized a 26 kDa Ca(2+)-binding protein from Xenopus laevis eggs, a homologue of Rana catesbeiana dicalcin (renamed from p26olf) that was isolated from the olfactory epithelium. The primary structure of Xenopus dicalcin shows approximately 61% identity to that of Rana dicalcin and consists of two S100-like regions aligned in tandem, as seen in Rana dicalcin. Genomic Southern blot analysis indicated that Xenopus dicalcin is a unique orthologue of Rana dicalcin. Northern blot analysis showed that Xenopus dicalcin mRNA is expressed in Xenopus eggs and also in other tissues. These results indicated that Xenopus dicalcin is a novel S100-like Ca(2+)-binding protein in Xenopus eggs.DNA Sequence 11/2007; 18(5):400-4. · 0.75 Impact Factor -
Article: Short report: the effect of expertise in hiking on recognition memory for mountain scenes.
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ABSTRACT: The nature of an expert memory advantage that does not depend on stimulus structure or chunking was examined, using more ecologically valid stimuli in the context of a more natural activity than previously studied domains. Do expert hikers and novice hikers see and remember mountain scenes differently? In the present experiment, 18 novice hikers and 17 expert hikers were presented with 60 photographs of scenes from hiking trails. These scenes differed in the degree of functional aspects that implied some action possibilities or dangers. The recognition test revealed that the memory performance of experts was significantly superior to that of novices for scenes with highly functional aspects. The memory performance for the scenes with few functional aspects did not differ between novices and experts. These results suggest that experts pay more attention to, and thus remember better, scenes with functional meanings than do novices.Memory 11/2007; 15(7):768-75. · 2.09 Impact Factor
Top co-authors
Top Journals
Institutions
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2001–2012
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Osaka University
- • Graduate School of Frontier Biosciences
- • Department of Biological Sciences
- • School of Human Sciences
Ōsaka-shi, Osaka-fu, Japan
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2009–2011
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Osaka Electro-Communication University
Neyagawa, Osaka-fu, Japan -
Osaka University of Human Sciences
Ōsaka-shi, Osaka-fu, Japan
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2007–2010
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Toho University
- Department of Physiology
Funabashi, Chiba-ken, Japan
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