脳情報学に基づく人間の認知・感情とその相互関係における研究

This dissertation concentrates on the neural substrates underlying the human cognition, emotion, and their interactions. Directed by the systematic methodology of brain informatics (BI), functional magnetic resonance imaging (fMRI) experiments were performed to investigate the information processing of mental arithmetic, self-regulation of aversive emotion, and attention deployment of patients with major depressive disorder (MDD), which were utilized as typical paradigms to study the relationship between cognition and emotion. Four major findings could be concluded: 1) mental addition calculation is naturally automaticwhile subtraction calculation is complex; 2) both bottom-up suppression and top-down regulation are engaged in the self-recovery from aversive emotion; 3) cognition and emotion influence each other, since some cognitive resources and brain regions are shared by the both brain functions; 4) Abnormal functioning in the joint brain areas is more likely to lead to impairments in both cognitive and emotional functions simultaneously. Our findings demonstrate that human cognition and emotion are not isolated, but compete for cognitive resources for attention and executive control. The present thesis can also be considered as a case study for demonstrating the advances of BI methodology in accelerating progress towards a multi-level understanding of brain structure and function.学位記番号:工博甲1

Terrestrial land cover shapes fish diversity in major subtropical rivers

Freshwater biodiversity is critically affected by human modifications of terrestrial land use and land cover (LULC). Yet, knowledge of the spatial extent and magnitude of LULC-aquatic biodiversity linkages is still surprisingly limited, impeding the implementation of optimal management strategies. Here, we compiled fish diversity data across a 160,000-km² subtropical river catchment in Thailand characterized by exceptional biodiversity yet intense anthropogenic alterations, and attributed fish species richness and community composition to contemporary terrestrial LULC across the catchment. We estimated a spatial range of LULC effects extending up to about 20 km upstream from sampling sites, and explained nearly 60% of the variance in the observed species richness, associated with major LULC categories including croplands, forest, and urban areas. We find that integrating both spatial range and magnitudes of LULC effects is needed to accurately predict fish species richness. Further, projected LULC changes showcase future gains and losses of fish species richness across the river network and offer a scalable basis for riverine biodiversity conservation and land management, allowing for potential mitigation of biodiversity loss in highly diverse yet data-deficient tropical to sub-tropical riverine habitats

Landscape of microalgae omics and metabolic engineering research for strain improvement: an overview

The unique metabolic capabilities and fast growth rates of microalgae render them promising candidates for various industrial applications, such as biofuel production, pharmaceuticals, nutraceuticals, and wastewater treatment. Metabolic engineering is a powerful approach used to enhance the sustainable production of high-value compounds in microalgae, improve their stress tolerance, growth characteristics and suitability for large-scale cultivation. This review provides a snapshot of the current state of knowledge on omics and metabolic engineering research to further enhance our understanding on microalgal metabolism and enable the development of optimized strains with improved productivity and functionality. More specifically, it focuses on the recent breakthroughs in microalgal omics, driven by advancements in genomics technologies, such as improved sequencing platforms and bioinformatics tools, that have enabled the functional characterization of key genes, identification of metabolic pathways, and elucidation of microalgae cell physiology. Conventional and state-of-the-art genetic engineering approaches used in the last decades to manipulate the metabolic pathways of microalgae in a targeted manner, are highlighted in the scope of microalgal optimization. In this review, the different applications of genetic engineering and their impact on microalgae industry are also discussed. Integrating pan-omics data in future research is crucial for predicting novel functional interactions and identifying aspects of metabolic flux, towards enhancing algal strain-engineering technique

Species identification approach for both raw materials and end products of herbal supplements from Tinospora species

Abstract Background Nowadays herbal products used in traditional medicine are sold in processed forms and thus morphological authentication is almost impossible. With herbal industry rapidly growing size, consumer safety becomes an important issue that requires special attention. Identification of herbal species in the products is therefore needed. Methods Sequences from the selected regions (matK, rbcL, trnL and ITS1) were retrieved and analysed. Then the most suitable barcode was assessed for discrimination of T. crispa from closely related species by HRM analysis and used in authentication of commercial products. Results The ITS1 barcode was found to be the suitable primer as melting data from the HRM assay proved to be capable of distinguishing T. crispa from its related species. The developed protocol was then employed to authenticate medicinal products in powdered form. HRM analysis of all tested samples here revealed that five out of eight products contained not only the indicated species T. crispa but also other Tinospora, that have a high level of morphological similarity. Conclusion Misrepresentation, poor packaging and inappropriate labeling of the tested medicinal herbal products are thought to be the reason of the results here. Using Bar-HRM with the ITS marker lead to success in authenticating the tested herbal products

Shedding light on eDNA: neither natural levels of UV radiation nor the presence of a filter feeder affect eDNA-based detection of aquatic organisms

The use of environmental DNA (eDNA) as a species detection tool is attracting attention from both scientific and applied fields, especially for detecting invasive or rare species. In order to use eDNA as an efficient and reliable tool, however, we need to understand its origin and state as well as factors affecting its degradation. Various biotic and abiotic environmental factors have been proposed to affect degradation of eDNA in aquatic environments and thus to influence detection rates of species. Here, we were interested in two of them, namely UV light, which can break down DNA, and the presence of filter feeders, which can remove DNA and DNA-bound particles. A few, mostly laboratory-based studies have found minor effects of UVB on the degradation of eDNA. Ultraviolet A radiation (UVA), however, has been neglected although it also causes DNA lesions and is 10- to 100-fold more prevalent than UVB when reaching the earth's surface. Filter feeders are common in aquatic ecosystem, but their effects on eDNA has hitherto been ignored. We conducted a full-factorial aquatic mesocosm experiment under near-natural outdoor conditions manipulating UV radiation as well as the presence of Dreissena polymorpha, a strong filter feeder capable of filtering cells or organelles containing DNA. Surprisingly, we found that neither UV radiation nor the presence of the filter feeder affected eDNA-based detection rates of macroinvertebrates, even though the experiment took place in summer when UV radiation intensity and filtration activity is high for the chosen experimental site and conditions. These results, in combination with studies from marine or laboratory settings finding no effect of sunlight and its UV components on the detectability of eDNA, suggest that eDNA based species assessments could be relatively robust with respect to our two factors studied

L'Asie, l'Insulinde, l'Afrique (Nouvelle édition...) / par MM. P. Vidal de La Blache et P. Camena d'Almeida

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Should DNA sequence be incorporated with other taxonomical data for routine identifying of plant species?

Abstract Background A variety of plants in Acanthaceae have long been used in traditional Thai ailment and commercialised with significant economic value. Nowadays medicinal plants are sold in processed forms and thus morphological authentication is almost impossible. Full identification requires comparison of the specimen with some authoritative sources, such as a full and accurate description and verification of the species deposited in herbarium. Intake of wrong herbals can cause adverse effects. Identification of both raw materials and end products is therefore needed. Methods Here, the potential of a DNA-based identification method, called Bar-HRM (DNA barcoding coupled with High Resolution Melting analysis), in raw material species identification is investigated. DNA barcode sequences from five regions (matK, rbcL, trnH-psbA spacer region, trnL and ITS2) of Acanthaceae species were retrieved for in silico analysis. Then the specific primer pairs were used in HRM assay to generate unique melting profiles for each plants species. Results The method allows identification of samples lacking necessary morphological parts. In silico analyses of all five selected regions suggested that ITS2 is the most suitable marker for Bar-HRM in this study. The HRM analysis on dried samples of 16 Acanthaceae medicinal species was then performed using primer pair derived from ITS2 region. 100% discrimination of the tested samples at both genus and species level was observed. However, two samples documented as Clinacanthus nutans and Clinacanthus siamensis were recognised as the same species from the HRM analysis. Further investigation reveals that C. siamensis is now accepted as C. nutans. Conclusions The results here proved that Bar-HRM is a promising technique in species identification of the studied medicinal plants in Acanthaceae. In addition, molecular biological data is currently used in plant taxonomy and increasingly popular in recent years. Here, DNA barcode sequence data should be incorporated with morphological characters in the species identification

Distinguishing fanged frogs (Limnonectes) species (Amphibia: Anura: Dicroglossidae), from Thailand using high resolution melting analysis

Abstract Morphologically, species of fanged frogs (Limnonectes) are exceedingly similar, making it difficult to distinguish them within the complex. In Thailand, it has been difficult to distinguish between the sympatric species L. bannaensis and L. taylori, particularly among tadpoles, adolescents, and adult females. A precise identification contributes to a greater understanding of biodiversity, particularly for assessing distributions and population dynamics. Therefore, a novel approach is required. The objective of this study was to develop a high resolution melting analysis (HRM) for the rapid and accurate identification of six species of Limnonectes of the L. kuhlii complex found in Thailand, particularly the two sympatric fanged frogs. Here, HRM assays using 16S rRNA mitochondrial primers were designed and developed. There was as much as a 25.3% variation in the nucleotide sequence of the fragment amplified by HRM16S primers among the six species of Limnonectes. Prior to conducting an in vitro HRM, the DNA sequences were used in a simulation HRM, uMELT Quartz, to predict the melting curve for each species of Limnonectes. There were discrepancies between the predicted melting curves of each species generated by the programme. Consequently, in vitro HRM tests were conducted. The obtained melting curve and Tm values were consistent with those predicted, albeit with a slightly different Tm value and a more distinct melting curve. All evaluated species of Limnonectes could be easily distinguished from one another by comparing the melting curve shapes. The HRM assay was then used to confirm the species of 18 Limnonectes samples in comparison to the reference samples (confidence interval > 90%). In addition, the results of HRM were consistent with those of experts who used morphological analysis to identify species. The HRM was found to be useful, and therefore the method would also contribute to future ecological and systematic studies on the target species

The Identification of Several Dipterocarpaceae and Fagaceae Trees by Barcode DNA Coupled with High-Resolution Melting Analysis

The loss of forests is a major environmental, social, and economic problem. The disappearance has been occurring to an extreme degree in many parts of Southeast Asia, including Thailand. Logging and clearing of forests for agriculture, cash crops, and food production has destroyed much of the tropical forests in Thailand. Floristic inventory could provide essential information for forest conservation but species identification as a part of inventory creating could be challenging in some cases. Barcode DNA coupled with High Resolution Melting analysis (Bar-HRM) was used here in aiding species identification of plant in Dipterocarpaceae (Dipterocarpus alatus, D. costatu, D. intricatus, D. obtusifolius, Hopea ferrea, H. odorata, Shorea guiso, S. obtuse, S. roxburghii, and S. siamensis) and Fagaceae (Castanopsis echinocarpa, C. inermis, Lithocarpus wallichianus, Quercus aliena and Q. oidocarpa) families. Two main experiments were conducted including: (1) a comparing method for primer design and (2) testing the robustness of the Bar-HRM by trying to identify tree samples that did not have sequences in the GenBank. In experiment 1, the manual design primer pair was found to be the best fit for the work. Of key importance is finding the primers which give the most nucleotide variations within the generated amplicon; this is a parameter that cannot be set in any web-based tools. Next, in experiment 2, Bar-HRM using primers of ITS1 and ITS2 regions were able to discriminate all 10 tested tree species without any problem, even when there were no sequences of the samples to be analysed before performing the HRM. Here, Bar-HRM poses potential to be a game-changer in tropical forest conservation, as it will be useful for species identification