OIST Institutional Repository
Not a member yet
2744 research outputs found
Sort by
Insufficient liver maturation affects murine early postnatal hair cycle
Get PDFAbnormal hair loss results from a variety of factors, such as metabolic dysfunctions, immunodeficiency, and environmental stressors. Here, we report that mutant mice having defects in liver function, develop alopecia. We have shown previously that in mice lacking a Cnot3 gene, which encodes an essential component of the CCR4-NOT deadenylase complex in liver (Cnot3-LKO mice), the liver does not mature properly, resulting in various pathologies such as hepatitis, hepatic necrosis, and anemia. Unexpectedly, Cnot3-LKO mice start to lose hair around postnatal day 17 (P17). The region of hair loss expands all across their backs and symptoms persist until around P28-30. Afterward, hair re-grows, and Cnot3-LKO mice show complete hair recovery by P40. The phenotype is dependent on mouse genotype, indicating that hair follicle morphogenesis and cycling are influenced by abnormal liver development. By performing histological, quantitative PCR, and immunoblot analyses, we detected sebaceous gland (SG) hypertrophy accompanied by an increase of peroxisome proliferator-activated receptor gamma (PPARgamma). Collectively, these findings suggest that paracrine signaling related to liver function influences hair growth, at least in part, by altering lipid metabolism.journal articl
Voltage imaging with ANNINE dyes and two-photon microscopy of Purkinje dendrites in awake mice
Get PDFVoltage imaging is the next generation of functional imaging in neuroscience. It promises to resolve neuronal activity 10 to 100-times faster than calcium imaging and to report not only supra but also subthreshold activity on a single cell or even subcellular level. Lately, several different voltage sensors and imaging techniques were published which can achieve this. Here, we focus on a technique based on the synthetic pure electrochromic voltage-sensitive dyes ANNINE-6 and ANNINE-6plus and the excitation of this dye at the red spectral edge of absorption to maximize voltage sensitivity and minimize phototoxicity and bleaching. Importantly, voltage imaging with ANNINE dyes can be done with one and two-photon excitation. Two-photon microscopy allows in vivo, depth resolved imaging and line-scan recordings with sub-millisecond temporal resolution. Interestingly for many future applications, the spectral characteristics of ANNINE dyes allows simultaneous imaging with green indicators, like the genetically encoded calcium indicator GCaMP6. We used this method to study supra and subthreshold dendritic voltage changes in Purkinje neurons of awake mice. Simultaneously, we imaged dendritic calcium and recorded electrical activity from the soma or locally applied drugs to show the full potential of the technique to study dendritic integration in awake animals.journal articl
Warm seawater temperature promotes substrate colonization by the blue coral, Heliopora coerulea
Get PDFBackground: Heliopora coerulea, the blue coral, is a reef building octocoral that is reported to have a higher optimum temperature for growth compared to most scleractinian corals. This octocoral has been observed to grow over both live and dead scleractinians and to dominate certain reefs in the Indo-Pacific region. The molecular mechanisms underlying the ability of H. coerulea to tolerate warmer seawater temperatures and to effectively compete for space on the substrate remain to be elucidated.
Methods: In this study, we subjected H. coerulea colonies to various temperatures for up to 3 weeks. The growth and photosynthetic efficiency rates of the coral colonies were measured. We then conducted pairwise comparisons of gene expression among the different coral tissue regions to identify genes and pathways that are expressed under different temperature conditions.
Results: A horizontal growth rate of 1.13 +/- 0.25 mm per week was observed for corals subjected to 28 or 31 degrees C. This growth rate was significantly higher compared to corals exposed at 26 degrees C. This new growth was characterized by the extension of whitish tissue at the edges of the colony and was enriched for a matrix metallopeptidase, a calcium and integrin binding protein, and other transcripts with unknown function. Tissues at the growth margin and the adjacent calcified encrusting region were enriched for transcripts related to proline and riboflavin metabolism, nitrogen utilization, and organic cation transport. The calcified digitate regions, on the other hand, were enriched for transcripts encoding proteins involved in cell-matrix adhesion, translation, receptor-mediated endocytosis, photosynthesis, and ion transport. Functions related to lipid biosynthesis, extracellular matrix formation, cell migration, and oxidation-reduction processes were enriched at the growth margin in corals subjected for 3 weeks to 28 or 31 degrees C relative to corals at 26 degrees C. In the digitate region of the coral, transcripts encoding proteins that protect against oxidative stress, modify cell membrane composition, and mediate intercellular signaling pathways were enriched after just 24 h of exposure to 31 degrees C compared to corals at 28 degrees C. The overall downregulation of gene expression observed after 3 weeks of sustained exposure to 31 degrees C is likely compensated by symbiont metabolism.
Discussion: These findings reveal that the different regions of H. coerulea have variable gene expression profiles and responses to temperature variation. Under warmer conditions, the blue coral invests cellular resources toward extracellular matrix formation and cellular migration at the colony margins, which may promote rapid tissue growth and extension. This mechanism enables the coral to colonize adjacent reef substrates and successfully overgrow slower growing scleractinian corals that may already be more vulnerable to warming ocean waters.journal articl
Photo-Fenton-like degradation of bisphenol A by persulfate and solar irradiation
Get PDFThis work evaluates the feasibility of a solar-enhanced Fenton-like process using S₂O₈²⁻ (PS) and Fe²⁺ for the elimination of BPA, a model endocrine-disruption compound. This comparative study of BPA removal showed that among the approaches employed, the effectiveness of BPA degradation (10mg/L) decreased in the order: Solar/PS/Fe²⁺> Solar/PS>PS/Fe²⁺> Solar/Fe²⁺> Solar. The complete degradation of BPA was achieved by Solar/PS/Fe²⁺ treatment at a [PS]:[BPA] ratio of 20 in less than t30W 5 in deionised water. The high efficiency of the Solar/PS/Fe²⁺ process revealed a synergistic effect (varphi=2.38) between the applied activation agents on the formation of reactive oxygen species (ROS) and subsequent decomposition of BPA. The treatment was accompanied by total organic carbon (TOC) removal (44%) in 45min. Sequential generation of reactive oxygen species has made Solar/PS/Fe²⁺ a kinetically effective process for removing BPA without accumulation of toxic intermediates. The reaction rate followed pseudo-first-order kinetics that increased with increasing PS and Fe²⁺ concentrations. Experimental evidence suggests that exposure to solar irradiation maintains suitable quantities of free Fe²⁺ in the reaction mixture, even at low catalyst concentrations (the molar ratio of [PS]:[Fe²⁺] varied from 1:0.01 to 1:0.08). The effects of HCO₃⁻, SO₄²⁻, and Cl⁻ were also examined. As expected, HCO₃⁻ and SO₄²⁻ inhibited BPA oxidation. The effect of Cl⁻ on the oxidation efficiency of BPA in Fenton-like systems depends not only on actual Cl⁻ concentrations but it is also highly influenced by molar ratios of Cl⁻ to oxidant and catalyst. Inhibition, which was caused by Cl⁻ in the mM range can be overcome by prolonging the reaction time or increasing the initial Fe²⁺concentration. Finally, the efficiency of Solar/PS/Fe²⁺ process was examined in diluted natural surface water and wastewater effluent. On eliminating the buffering action of HCO₃⁻/CO₃²⁻ ions by lowering the pH value to 4.5, complete BPA degradation was achieved in all real water matrices.journal articl
Whole-genome sequence analysis of the evolutionary history of the reef-building coral genus Acropora (Scleractinia, Cnidaria)
Get PDFOkinawa Institute of Science and Technology Graduate UniversityDoctor of PhilosophyA major goal of evolutionary biology is to understand the roles of evolutionary and ecological factors in rapid speciation and diversification. Introgression and ancient large-scale/whole genome duplication (paleopolyploidy) have been hypothesized to promote on rapid speciation leading to diversification. In addition, diversification can be promoted by ‘ecological opportunity’ created by extinction of competitors or the colonization of a new area. Reef-building corals are the foundation of diverse tropical ecosystems, but are currently under threat due to the sensitivity of corals to climate change and anthropogenic factors. Acropora (Anthozoa: Acroporidae) is one of the most diverse genera of reef-building corals, including more than 150 species, and based on the fossil record has dominated IndoPacific reefs in past 3 Million Years, yet the evolutionary and ecological factors associated with its diversification and the rise to dominance are unclear. Understanding the evolutionary history of this group during its rise to dominance may help understanding their current and future responses to global change. In this dissertation, I used genomic data of Acropora generated by Dr. Chuya Shinzato to investigate its evolutionary history and illuminate the roles of introgression, largescale genome duplication, and ecological opportunity in its diversification and the rise to dominance. In the first chapter, I reviewed recent studies of Acropora. In the second chapter, I examined the roles of introgression in Acropora. I found that a major introgression event and widespread gene flow occurred in five Acropora species, and that introgression genes evolved faster than others. In the third chapter, I examined the roles of climate change in the rise to dominance of Acropora. I found that Acropora lineages had an experience of population expansion after a climatedriven mass extinction event in the Plio-Pleistocene, suggesting ecological opportunity facilitated the rise to dominance of Acropora. In the fourth chapter, I examined evidence for large-scale genome duplication and its consequences in Acropora. I found a large-scale genome duplication event likely occurred in Acropora and duplicated genes play important roles in the diversification of Acropora. Finally, in the fifth chapter, I discussed limitations and future directions arising from this dissertation. Collectively, this dissertation suggests that introgression, climate change, and large-scale genome duplication play important roles in the evolutionary history of Acropora.doctoral thesi
Impact of a local, coastal community based management regime when defining marine protected areas: Empirical results from a study in Okinawa, Japan
Get PDFThere is a growing impetus to increase marine protected areas coverage globally from 6% to 30% in 2030. Successfully establishing and maintaining marine protected areas require incorporating public preferences into their establishment and management. We investigate the role of alternate management regimes (top-down and bottom-up) on preferences for marine protected areas and the marginal rate of substitution between natural and man-made capital using a case study in the Asia-Pacific region of Okinawa, Japan. We implemented a choice experiment survey to infer which attributes of marine protected areas are most important for the respondents. We use our survey results to calculate respondents' willingness to support marine protected areas in Okinawa. This study contributes to the policy debate on management of marine protected areas with empirical data that characterizes the perception of Okinawan residents with respect to the role of local coastal communities (bottom-up) compared to central government based agencies (top-down) management. We extend the analysis and estimate the trade-offs to residents in Okinawa between natural capital (i.e. coral coverage and marine biodiversity attribute) and man-made capital (i.e. restrictions on coastal development). We find that the underlying management regime affects the local residents' valuation of the marine protected area with residents showing a higher willingness to support bottom-up management regimes. There is also substantial differences in the willingness to support different characteristics of marine protected areas by management type. Finally, we find that the marginal rate of substitution between natural capital and man-made capital varies by management type such that residents would need to be compensated relatively less in terms of man-made capital in the presence of a policy scenario that proposes an increase in natural capital under a bottom-up management regime.journal articl
Active propagation of dendritic electrical signals in C. elegans
Get PDFActive propagation of electrical signals in C. elegans neurons requires ion channels capable of regenerating membrane potentials. Here we report regenerative depolarization of a major gustatory sensory neuron, ASEL. Whole-cell patch-clamp recordings in vivo showed supra linear depolarization of ASEL upon current injection. Furthermore, stimulation of animal's nose with NaCI evoked all-ornone membrane depolarization in ASEL. Mutant analysis showed that EGL-19, the oil subunit of L-type voltage-gated Ca2+ channels, is essential for regenerative depolarization of ASEL. ASEL-specific knock-down of EGL-19 by RNAi demonstrated that EGL-19 functions in C. elegans chemotaxis along an NaCI gradient. These results demonstrate that a natural substance induces regenerative all-or-none electrical signals in dendrites, and that these signals are essential for activation of sensory neurons for chemotaxis. As in other vertebrate and invertebrate nervous systems, active information processing in dendrites occurs in C. elegans, and is necessary for adaptive behavior.journal articl
Glioblastoma adhesion in a quick-fit hybrid microdevice
Get PDFTranslational research requires reliable biomedical microdevices (BMMD) to mimic physiological conditions and answer biological questions. In this work, we introduce a reversibly sealed quick-fit hybrid BMMD that is operator-friendly and bubble-free, requires low reagent and cell consumption, enables robust and high throughput performance for biomedical experiments. Specifically, we fabricate a quick-fit poly(methyl methacrylate) and poly(dimethyl siloxane) (PMMA/PDMS) prototype to illustrate its utilities by probing the adhesion of glioblastoma cells (T98G and U251MG) to primary endothelial cells. In static condition, we confirm that angiopoietin-Tie2 signaling increases the adhesion of glioblastoma cells to endothelial cells. Next, to mimic the physiological hemodynamic flow and investigate the effect of physiological electric field, the endothelial cells are pre-conditioned with concurrent shear flow (with fixed 1 Pa shear stress) and direct current electric field (dcEF) in the quick-fit PMMA/PDMS BMMD. With shear flow alone, endothelial cells exhibit classical parallel alignment; while under a concurrent dcEF, the cells align perpendicularly to the electric current when the dcEF is greater than 154 V m(-1). Moreover, with fixed shear stress of 1 Pa, T98G glioblastoma cells demonstrate increased adhesion to endothelial cells conditioned in dcEF of 154 V m(-1), while U251MG glioblastoma cells show no difference. The quick-fit hybrid BMMD provides a simple and flexible platform to create multiplex systems, making it possible to investigate complicated biological conditions for translational research.journal articl
Transcriptomic basis and evolution of the ant nurse-larval social interactome
Get PDFDevelopment is often strongly regulated by interactions among close relatives, but the underlying molecular mechanisms are largely unknown. In eusocial insects, interactions between caregiving worker nurses and larvae regulate larval development and resultant adult phenotypes. Here, we begin to characterize the social interactome regulating ant larval development by collecting and sequencing the transcriptomes of interacting nurses and larvae across time. We find that the majority of nurse and larval transcriptomes exhibit parallel expression dynamics across larval development. We leverage this widespread nurse-larva gene co-expression to infer putative social gene regulatory networks acting between nurses and larvae. Genes with the strongest inferred social effects tend to be peripheral elements of within-tissue regulatory networks and are often known to encode secreted proteins. This includes interesting candidates such as the nurse-expressed giant-lens, which may influence larval epidermal growth factor signaling, a pathway known to influence various aspects of insect development. Finally, we find that genes with the strongest signatures of social regulation tend to experience relaxed selective constraint and are evolutionarily young. Overall, our study provides a first glimpse into the molecular and evolutionary features of the social mechanisms that regulate all aspects of social life.journal articl
Hybrid chemical vapor deposition enables scalable and stable Cs-FA mixed cation perovskite solar modules with a designated area of 91.8 cm2 approaching 10% efficiency
Get PDFThe development of scalable deposition methods for stable perovskite layers is a prerequisite for the development and future commercialization of perovskite solar modules. However, there are two major challenges, i.e., scalability and stability. In sharp contrast to a previous report, here we develop a fully vapor based scalable hybrid chemical vapor deposition (HCVD) process for depositing Cs-formamidinium (FA) mixed cation perovskite films, which alleviates the problem encountered when using conventional solution coating of mainly methylammonium lead iodide (MAPbI3). Using our HCVD method, we fabricate perovskite films of Cs0.1FA0.9PbI2.9Br0.1 with enhanced thermal and phase stabilities, by the intimate incorporation of Cs into FA based perovskite films. In addition, the SnO2 electron transport layer (ETL) (prepared by sputter deposition) is found to be damaged during the HCVD process. In combination with precise interface engineering of the SnO2 ETL, we demonstrate relatively large area solar modules with efficiency approaching 10% and with a designated area of 91.8 cm2 fabricated on 10 cm × 10 cm substrates (14 cells in series). On the basis of our preliminary operational stability tests on encapsulated perovskite solar modules, we extrapolated that the T80 lifetime is approximately 500 h (under the light illumination of 1 sun and 25 °C).journal articl