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71.
Kohei Fujikura Tomiyoshi Setsu Kenji Tanigaki Takaya Abe Hiroshi Kiyonari Toshio Terashima Toshiaki Sakisaka 《PloS one》2013,8(1)
We describe a novel spontaneous mouse mutant, laggard (lag), characterized by a flat head, motor impairment and growth retardation. The mutation is inherited as an autosomal recessive trait, and lag/lag mice suffer from cerebellar ataxia and die before weaning. lag/lag mice exhibit a dramatic reduction in brain size and slender optic nerves. By positional cloning, we identify a splice site mutation in Kif14. Transgenic complementation with wild-type Kif14-cDNA alleviates ataxic phenotype in lag/lag mice. To further confirm that the causative gene is Kif14, we generate Kif14 knockout mice and find that all of the phenotypes of Kif14 knockout mice are similar to those of lag/lag mice. The main morphological abnormality of lag/lag mouse is severe hypomyelination in central nervous system. The lag/lag mice express an array of myelin-related genes at significantly reduced levels. The disrupted cytoarchitecture of the cerebellar and cerebral cortices appears to result from apoptotic cell death. Thus, we conclude that Kif14 is essential for the generation and maturation of late-developing structures such as the myelin sheath, cerebellar and cerebral cortices. So far, no Kif14-deficient mice or mutation in Kif14 has ever been reported and we firstly define the biological function of Kif14 in vivo. The discovery of mammalian models, laggard, has opened up horizons for researchers to add more knowledge regarding the etiology and pathology of brain malformation. 相似文献
72.
Yoritaka Akimoto Akitake Kanno Toshimune Kambara Takayuki Nozawa Motoaki Sugiura Eiichi Okumura Ryuta Kawashima 《PloS one》2013,8(3)
Although many studies have investigated the neural basis of top-down and bottom-up attention, it still requires refinement in both temporal and spatial terms. We used magnetoencephalography to investigate the spatiotemporal dynamics of high-gamma (52–100 Hz) activities during top-down and bottom-up visual attentional processes, aiming to extend the findings from functional magnetic resonance imaging and event-related potential studies. Fourteen participants performed a 3-stimulus visual oddball task, in which both infrequent non-target and target stimuli were presented. We identified high-gamma event-related synchronization in the left middle frontal gyrus, the left intraparietal sulcus, the left thalamus, and the visual areas in different time windows for the target and non-target conditions. We also found elevated imaginary coherence between the left intraparietal sulcus and the right middle frontal gyrus in the high-gamma band from 300 to 400 ms in the target condition, and between the left thalamus and the left middle frontal gyrus in theta band from 150 to 450 ms. In addition, the strength of high-gamma imaginary coherence between the left middle frontal gyrus and left intraparietal sulcus, between the left middle frontal gyrus and the right middle frontal gyrus, and the high-gamma power in the left thalamus predicted inter-subject variation in target detection response time. This source-level electrophysiological evidence enriches our understanding of bi-directional attention processes: stimulus-driven bottom-up attention orientation to a salient, but irrelevant stimulus; and top-down allocation of attentional resources to stimulus evaluation. 相似文献
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75.
Songling?Bai Pham?Anh?Tuan Takanori?Saito Chikako?Honda Yoshimichi?Hatsuyama Akiko?Ito Takaya?MoriguchiEmail author 《Planta》2016,244(3):573-586
Main conclusion
Paper-bagging treatment can transform non-transcribed MdMYB1 - 2 and MdMYB1 - 3 alleles into transcribed alleles through epigenetic regulations, resulting in the red pigmentation of a normally non-red apple cultivar ‘Mutsu.’ Anthocyanin biosynthesis in apples is regulated by MdMYB1/A/10, an R2R3-Type MYB gene. ‘Mutsu,’ a triploid apple cultivar harboring non-transcribed MdMYB1-2 and MdMYB1-3 alleles, retains green skin color under field conditions. However, it can show red/pink pigmentation under natural or artificial ultraviolet-B (UV-B) light exposure after paper-bagging and bag removal treatment. In the present study, we found that in ‘Mutsu,’ paper bagging-induced red pigmentation was due to the activation of non-transcribed MdMYB1-2/-3 alleles, which triggered the expression of downstream anthocyanin biosynthesis genes in a UV-B-dependent manner. By monitoring the epigenetic changes during UV-B-induced pigmentation, no significant differences in DNA methylation and histone modifications in the 5′ upstream region of MdMYB1-2/-3 were recorded between the UV-B-treated fruit skin (red) and the fruit skin treated only by white light (green). In contrast, bag treatment lowered the DNA methylation in this region of MdMYB1-2/-3 alleles. Similarly, higher levels of histone H3 acetylation and trimethylation of H3 tail at lysine 4, and lower level of trimethylation of H3 tail at lysine 27 were observed in the 5′ upstream region of MdMYB1-2/-3 in the skin of the fruit immediately after bag removal. These results suggest that bagging treatment can induce epigenetic changes, facilitating the binding of trans factor(s) to MdMYB1-2/-3 alleles, resulting in the activation of these MYBs after bag removal.76.
77.
Shinji Sugiura 《Ecological Research》2016,31(2):155-164
Introduced species negatively impact native species through competitive and trophic interactions, particularly on oceanic islands that have never been connected to any continental landmass. However, there are few studies on the relative importance of competitive interactions (resource competition with introduced species) and trophic interactions (predation or herbivory by introduced species) with respect to the negative impacts on native organisms on oceanic islands. A literature review on introduced and native species of the oceanic Ogasawara (Bonin) Islands in the western Pacific Ocean indicated that many native species (e.g., bees, beetles, damselflies, butterflies, land snails, birds, and plants) have been negatively impacted by introduced predators and herbivores (e.g., lizards, rats, flatworms, and goats). Several native plants and bees have been negatively affected by introduced competitors. However, the native species that have competed with introduced species have also suffered from either intense herbivory or predation by other introduced species. Thus, introduced predators and herbivores have had greater impacts on native species than introduced competitors in the Ogasawara Islands. 相似文献
78.
Male solitary bees typically use emergence‐nesting areas and/or flower patches of food plants, where receptive females are relatively numerous, as rendezvous sites. However, mate‐seeking males have been also observed at food‐deceptive orchid patches, where numerous encounters with foraging females can hardly be expected, owing to the lack of floral rewards. Here, we describe the male mate‐seeking and mating behaviors of the Japanese long‐horned bee Eucera nipponensis at habitats of the food‐deceptive orchid Cymbidium goeringii. On the basis of the results, we report empty flower patches are not necessarily fruitless sites for mate‐seeking males because naive female bees, which are highly likely to be recently emerged and unmated, can be attracted to non‐rewarding orchids. We also suggest a possibility that a small number of the males could receive a “sexual reward” (i.e. mating opportunities), owing to the food‐deceptive orchid, in return for their pollination work. This occasional interaction could represent the initial stage in the evolution of sexually deceptive orchids from food‐deceptive orchids. 相似文献
79.
Sugiura T Horiguchi H Sugahara K Takeda C Samejima M Fujii A Okita Y 《Journal of physiological anthropology》2007,26(2):257-259
Preliminary experiments were carried out to investigate the feasibility of using an electroencephalogram and heart rates to evaluate the efficacy of finger acupressure on the key points of planta pedis (both soles). Continuous electroencephalograms were recorded from 19 electrodes based on the International 10-20 electrode placement system on 22 university students (21+/-2.3 years). Spectral power changes were obtained at each electrode site. The power of the alpha1 frequency range (8-10 Hz) increased slightly during acupressure although no statistical significance was observed, while heart rates decreased in all subjects (p<0.05). Cerebral cortex asymmetry in the spectral power changes was not clearly observed during the right and left sole acupressure. This preliminary study suggests that a classification of subjects is necessary in understanding brain wave data during acupressure on soles. 相似文献
80.
Yuki Takegawa Makoto Nakamura Shin Nakamura Takumi Noguchi Julien Sellés A. William Rutherford Alain Boussac Miwa Sugiura 《BBA》2019,1860(4):297-309
The monomeric chlorophyll, ChlD1, which is located between the PD1PD2 chlorophyll pair and the pheophytin, PheoD1, is the longest wavelength chlorophyll in the heart of Photosystem II and is thought to be the primary electron donor. Its central Mg2+ is liganded to a water molecule that is H-bonded to D1/T179. Here, two site-directed mutants, D1/T179H and D1/T179V, were made in the thermophilic cyanobacterium, Thermosynechococcus elongatus, and characterized by a range of biophysical techniques. The Mn4CaO5 cluster in the water-splitting site is fully active in both mutants. Changes in thermoluminescence indicate that i) radiative recombination occurs via the repopulation of *ChlD1 itself; ii) non-radiative charge recombination reactions appeared to be faster in the T179H-PSII; and iii) the properties of PD1PD2 were unaffected by this mutation, and consequently iv) the immediate precursor state of the radiative excited state is the ChlD1+PheoD1? radical pair. Chlorophyll bleaching due to high intensity illumination correlated with the amount of 1O2 generated. Comparison of the bleaching spectra with the electrochromic shifts attributed to ChlD1 upon QA? formation, indicates that in the T179H-PSII and in the WT*3-PSII, the ChlD1 itself is the chlorophyll that is first damaged by 1O2, whereas in the T179V-PSII a more red chlorophyll is damaged, the identity of which is discussed. Thus, ChlD1 appears to be one of the primary damage site in recombination-mediated photoinhibition. Finally, changes in the absorption of ChlD1 very likely contribute to the well-known electrochromic shifts observed at ~430?nm during the S-state cycle. 相似文献