An associative learning, in which an animal links sensory experiences to salient life events such as encountering foods under starved condition, is one of our fundamental brain functions. The long-term goal of our lab is to understand the neural mechanism underlying this associative learning. Our current focus is to identify and functionally characterize the neural circuits for memory formation, consolidation and recall. To this end, we investigate associative memories in the fruit fly, Drosophila melanogaster, by combining its powerful genetic tools, techniques of quantitative behavioral analyses, and high-resolution anatomical analyses of neurons. We also engage in the development of new techniques for behavioral analysis and the application of new genetic tools to push the boundaries of our analyses.
Within group-living animals, individuals appropriately tailor attitudes and responses to other group members according to the social context and external environment.At the simplest level, the behavioral output can be described as approach and affiliation (positive response) versus agonistic behavior and avoidance (negative response).The neural substrate that works between sensory input and behavioral output, or the integrative circuits underlying social recognition and behavioral choice, however, is vast and mysterious.To address this issue, we have focused on medaka fish, a model animal used mainly in the field of molecular genetics. We established various behavior paradigms to assess social interactions such as schooling behavior (Imada et al., 2010), female mate preference (Okuyama et al., 2014), male mate-guarding (Yokoi et al., 2015, 2016), and social learning (Ochiai et al., 2013). We found that medaka fish haveabilities of familiarity recognition (Okuyama et al., 2014, Isoe et al., 2016, Yokoi et al., 2016), and they use faces (head part) for individual recognition (Wang & Takeuchi 2017).Now CRISPR/Cas9 system is available in medaka fish, which allows us to generate efficiently knock-out and knock-in medaka.Using the medaka systems, we are trying to systematically identify internal factors (genes, neurons, and neural circuit) essential for the social interactions and clarify how these factors construct a brain network for social adaptation.
Animals grow up under the influence of their environment and society and, even into adulthood, they are continuously changing in response to new information. The structure and function of the brain’s neural network plastically change not only during development but also in adults. Our laboratory studies the mechanisms behind brain development and changes by examining the following systems: songbird vocal communication, rodent learning abilities, brain impairment under pathophysiological conditions, and gene transcription regulation in cultured cells or in vivo. We use experimental methods in the fields of molecular biology, cell biology, along with brain imaging and optogenetics to conduct behavioral analyses. We hope that our research will contribute to a better understanding of the basal mechanism of brain function and will serve as a foundation for the development of remedies for brain disorders.
Elucidation of the higher function of the brain is one of the most important subjects of the human being in the 21st century. For this subject, we believe that we should know much more about the functional architecture of the brain. We have to make the following items clear in our understandings,
1)the localization of individual functional unit inside the brain, and their co-operative mechanisms (way of unification as a system).
2)the neuronal mechanisms underlying individual brain function.
3)the neuronal representation of information in the brain.
4)the algorithm of information processing in the brain.
We are now trying to understand these objects through anatomical and physiological studies.
Our bodies consist of tens of trillions of cells, which are considered to be the basic units of life. Within cells, there are also numerous intracellular membranous structures, called organelles (such as the nucleus, endoplasmic reticulum, and the Golgi apparatus) that possess various functions, and these organelles frequently exchange information through “membrane traffic.” When proper membrane traffic is lost, humans often develop various diseases. For this reason, elucidating the molecular mechanisms of membrane traffic is an important research topic in the filed of biology and medicine. In order to perform membrane traffic smoothly, the presence of a “traffic controller” is crucial. We are working on elucidating the molecular mechanisms of membrane traffic by clarifying the role of membrane trafficking proteins, such as the Rab family small GTPases.
During embryonic development, cells divides, change their shapes, and migrate within an embryo, to form a complex body structure. To study these dynamic cellular behaviors, we use the nematode Caenorhabditis elegans as a model system, in which the complete cell lineage and the genome sequence is elucidated. Using molecular genetic and cell biological approaches, we aim to understand how cellular dynamics are molecularly regulated. Currently we focus on the following topics: 1) How microtubules are spatially and temporally regulated in mitosis and meiosis. 2) How germ granules?cytoplasmic organelles in germline cells?are formed and segregated. 3) How epidermal cell shape changes are coordinately regulated during morphogenesis. We also aim to develop new techniques and tools for manipulation of gene functions and high-resolution live-imaging.
Laboratory of Organelle Pathophysiology
Professor Tomohiko Taguchi ， Assistant Professor Kojiro Mukai
E-mail tomohiko.taguchi.b8＊tohoku.ac.jp (Please replace "＊" with "@" )
Eukaryotic cells have a number of intracellular organelles with distinct functions. Interestingly enough, these organelles never function alone; they cooperatively regulate cellular homeostasis, proliferation, and differentiation, through a continuous exchange of soluble and membrane-bound molecules via membrane trafficking and/or membrane contact transfer. A failure in organelle cooperation often results in various human diseases. Our laboratory uses methods in biochemistry, cell biology, and molecular biology to identify novel organellar proteins and lipids. With these methods, we aim to unveil novel functions of organelles and the molecular mechanisms that regulate organelle cooperation. We especially focus on molecules that reside on the cytoplasmic face of the organelles; the essential face that physically interacts with other organelles and cytosol. Our results will help develop new treatments for diseases such as cancer and autoinflammatory diseases that are caused by disrupted organelle cooperation.
Laboratory of Plant Developmental Biology
Professor Junko Kyozuka , Assistant Professor Hiromu Kameoka , Assistant Professor Aino Komatu
E-mail Junko.kyozuka.e4*tohoku.ac.jp (Please replace "＊" with "@" )
The basic strategy of plant development is different from that of animals. Plants start their life from a simple structure and continue morphogenesis throughout their lifetime. The key to this lifecycle is the activity of stem cells in the meristem. In principle, the meristem has an indeterminate activity and continues to produce next order meristems to establish an elaborate structure. However, each meristem eventually proceeds to a final determinate fate, the floral meristem, and becomes a flower for reproduction. Thus, the timing of the change from indeterminate to determinate phase is critical for plant architecture, in particular, inflorescence structure, and for successful reproduction. The aim of our research is to understand the molecular basis of the regulation of timing of the meristem phase change. We used the development of rice inflorescence as a model system and identified several genes that play critical roles in this process. Currently, we are making progress towards fully understanding the molecular and genetic roles of these critical regulators. We also use a bryophyte (Marchantia polymorpha) to reveal possible ancestral roles of the regulators and Arabidopsis to understand the diversification of their developmental functions.
The development of multicellular organisms involves the collective effect of multiple events at the single-cell level, such as proliferation, differentiation, migration, and death. Programmed cell death, for example, is a process by which cells are selected for death at set times in development, allowing for the sculpting of tissue, and is used in the adult organism to maintain homeostasis by eliminating cells that have developed abnormalities. Cell death plays an important role in maintaining the cellular population, not only by eliminating unneeded cells at given sites and stages, but also in other functions, such as regulating the proliferation and migration of neighboring cells. Such cellular behaviors give rise to cell networks capable of organizing into tissues, the study of which requires an experimental approach to spatiotemporal information in living systems, which can be obtained through the real-time live imaging of biological phenomena. To study the coordination of morphogenesis through live-imaging and genetic screens, we use the fruit fly, Drosophila melanogaster, as our primary research model, in order to take advantage of its utility in developmental studies and wealth of genetic data. Our research primarily focuses on the morphogenetic processes involved in cellular migration and cell death, such as the looping morphogenesis of fly male terminalia and the abdominal epidermis rearrangement, in order to understand the principles for morphogenetic dynamics.
Mechanism of organ morphogenesis, by using the appendages of vertebrates as a model
Basic morphology of external shapes and internal structures of animals are created during the developmental process by an intrinsic program in embryos. We investigate the mechanism of developmental program for morphology, which gives individual organs unique functional shapes, by using the appendages (limbs and fins) of vertebrates as a model.
Xenopus, an anuran, can fully regenerate limbs at the larval stage. However, adults can only regenerate incomplete structures called spikes. Our objective is to identify the abilities required for regenerating morphologically and functionally limbs, by investigating the factors that inhibit the generation of complete limbs, and also the reasons why mammals, including humans, have very low limb regeneration ability.
Ecosystems are interplay of organisms (players) and physical-chemical environments (arena). To forecast ecosystem responses to changing environments, therefore, it is crucial to know how organisms maximize their fitness through interactions with other organisms and abiotic environments and how they function in given ecosystems. From such a viewpoint, this laboratory is performing theoretical, experimental and field studies to elucidate biological processes structuring animal communities and ecosystem responses to global and local environmental changes. To accomplish this object, we specifically study population genetics of planktonic and benthic animals, trophic and food web dynamics, and material flows in selected ecosystems such as lakes, rivers and coastal waters using techniques in molecular ecology, biogeochemistry and ecological stoichiometry.
We study interactions between plants and the environment. Our interest is physiological mechanisms and evolutionary significance of plant functional traits to adapt to the environment. We analyze plants from protein to ecosystem levels. We use field plants, laboratory-grown plants and computer simulations. Recently we have intensively studied plant responses to global change. We have investigated effects of elevated CO2 on various plant traits such as photosynthesis, growth, seed production and leaf turnover. We have also studied evolutionary responses of plants to elevated CO2 using plants growing natural CO2 springs. Now we are trying to produce plants having higher yield under future environment.
We are trying to pursue problems as to why and how biodiversity has been evolved and maintained. Particularly, we try to solve problems why some organism can evolve to adapt to various environments, while other cannot. Species that can adapt to various and changing environments might have some genetic and genomic basis conferring high evolvability. We apply to various approaches from genomics to macroecology for solving these problems.
Laboratory of Plant Ecology
Professor Toru Nakashizuka , Associate Professor Satoki Sakai , Assistant Professor Hiroshi Ota , Assistant Professor Kazutaka Kawatsu
E-mail michio.kondo.b8＊tohoku.ac.jp (Please replace "＊" with "@" )
A number of diverse organisms, and various non-living components, interact with each other to give rise to the natural ecosystem. What determines the balance, patterns and stability at the different organizational levels of population, community, and ecosystem? How and why are organisms so diverse? What are the roles of evolutionary and ecological processes in the emergence and persistence of ecological systems? What keeps the ecosystem functional in nature? How can we cope with the “balance of nature”? We utilize multiple approaches to understand ecological systems, including observations or experiments in the field or laboratory, data analysis using mathematical or statistical tools, and conceptual modeling.
Laboratory of Plant Taxonomy and Phylogenetics
Professor Masayuki Maki , Assistant Professor Koji Yonekura , Assistant Professor Motonari Ohyama
E-mail maki＊m.tohoku.ac.jp (Please replace "＊" with "@" )
Land plants have highly diversified in any places on the earth. To analyze the mechanisms originating the plant diversity and to describe it from the viewpoint of natural history, we are employing multidisciplinary approaches based on molecular phylogenetics, population genetics, morphology, taxonomy, and dendrochronology. In particular, we are currently focusing on genetic differentiation at population to species level in the plants in Asian flora, natural hybridization in Japanese flora, coevolution of plants and animals or fungi, plant taxonomical and floristic studies in Asia, and estimation of past climate from tree-ring dating. We are also performing conservation biology of wild threatened plants in Japan. Our laboratory is composed by staff of Botanical Garden of Tohoku University in Kawauchi, Sendai and a branch garden in Mt. Hakkoda, Aomori.
Laboratory of Conservation Biology
Professor Satoshi Chiba , Associate Professor Takahiro Hirano
E-mail schiba＊biology.tohoku.ac.jp (Please replace "＊" with "@" )
Our current research focuses on ecology, evolutionary biology and conservation biology, and involves a combination of laboratory experiments, theoretical model and field studies. Questions we are addressing are: what ecological factors cause diversification of species; what determines spatial and temporal patterns of species diversity; what are responsible for evolutionary novelties; and how do we conserve biodiversity when human disturbances have strongly affected ecosystems. Our work becomes increasingly focused on conservation of threatened ecosystem and recovery of endangered species. We have also started monitoring the fluctuation of lake and forest environments by using NOAA images. Addition to these surveys, the laboratory studies using model ecosystem (microcosm) are also involved.
Laboratory of Developmental Biology
Professor Gaku Kumano , Associate Professor Takuya Minokawa , Assistant Professor Ayaki Nakamoto , Assistant Professor Satoshi Takeda
E-mail kumano＊m.tohoku.ac.jp (Please replace "＊" with "@" )
Our research center is located in a local town named Asamushi in the “Mutsu” bay area of northern Japan, which is known as one of the richest place in marine lives in the Tohoku area. Benefitted from our location in such place, we are using a variety of marine invertebrate species available in the sea around us (see the images) and are interested in understanding molecular and cellular mechanisms and evolutionary aspects of early development of these animals, ranging from egg maturation through fertilization to embryogenesis. We are working on several issues in the above research field using techniques such as micro-manipulation, molecular biology and live imaging, and hope to discover more and more of surprising and beautiful logics of developmental and evolutionary processes behind the marine lives as we are just beginning to understand these little-studied animals.
While rapidly accumulating life information such as genome sequences and gene expressions due to technological innovation such as next generation sequencer, how to find the biological significance from the vast amounts of information is increasingly important in the future. We conduct evolutionary analyses of genes and genomes for understanding genetic background of interesting phenotypes by using such large-scale life information. In particular, we work on the influence of duplicated genes on phenotypes such as human diseases and ecological characteristics.