The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Hisayoshi Nozaki - One of the best experts on this subject based on the ideXlab platform.

  • The Simplest Integrated Multicellular Organism Unveiled
    PloS one, 2013
    Co-Authors: Yoko Arakaki, Hiroko Kawai-toyooka, Yuki Hamamura, Tetsuya Higashiyama, Akira Noga, Masafumi Hirono, Bradley J. S. C. Olson, Hisayoshi Nozaki
    Abstract:

    Volvocine green algae represent the “evolutionary time machine” model lineage for studying Multicellularity, because they encompass the whole range of evolutionary transition of Multicellularity from unicellular Chlamydomonas to >500-celled Volvox. Multicellular volvocalean species including Gonium pectorale and Volvox carteri generally have several common morphological features to survive as integrated Multicellular Organisms such as “rotational asymmetry of cells” so that the cells become components of the individual and “cytoplasmic bridges between protoplasts in developing embryos” to maintain the species-specific form of the Multicellular individual before secretion of new extracellular matrix (ECM). However, these morphological features have not been studied in the four-celled colonial volvocine species Tetrabaena socialis that is positioned in the most basal lineage within the colonial or Multicellular volvocine greens. Here we established synchronous cultures of T. socialis and carried out immunofluorescence microscopic and ultrastructural observations to elucidate these two morphological attributes. Based on immunofluorescence microscopy, four cells of the mature T. socialis colony were identical in morphology but had rotational asymmetry in arrangement of microtubular rootlets and separation of basal bodies like G. pectorale and V. carteri. Ultrastructural observations clearly confirmed the presence of cytoplasmic bridges between protoplasts in developing embryos of T. socialis even after the formation of new flagella in each daughter protoplast within the parental ECM. Therefore, these two morphological attributes might have evolved in the common four-celled ancestor of the colonial volvocine algae and contributed to the further increase in cell number and complexity of the Multicellular individuals of this model lineage. T. socialis is one of the simplest integrated Multicellular Organisms in which four identical cells constitute the individual.

Kunihiko Kaneko - One of the best experts on this subject based on the ideXlab platform.

  • On Compatible Condition for Morphogenetic Diversity and Recursive Production of Multicellular Organisms
    Seibutsu Butsuri, 2007
    Co-Authors: Hiroshi Yoshida, Chikara Furusawa, Kunihiko Kaneko
    Abstract:

    The development of a Multicellular Organism is a dynamic process. With the increase of the cell number, starting from one or a few cells, cells are differentiated with different compositions. These differet types of cells form an ordered pattern. It is rather surprising that differentiation in cell types and formation of controlled patterns are compatible, because the former gives morphogenetic diversification whereas the latter implies recursive production of a cell ensemble, reducing individual differences. We studied this problem by taking a simple cell model with intracellular reaction dynamics of chemical concentrations, cell-cell interactions, and increase in cell numbers. We show that, by starting from an initial object consisting of both the cell type with diverse chemicals and the differentiated cell type, the recursive production of a Multicellular Organism with morphogenetic diversity is possible.

  • Selection of initial conditions for recursive production of Multicellular Organisms.
    Journal of theoretical biology, 2004
    Co-Authors: Hiroshi Yoshida, Chikara Furusawa, Kunihiko Kaneko
    Abstract:

    Abstract The development of a Multicellular Organism is a dynamic process. Starting from one or a few cells, the Organism becomes a set of cells with different types that form well-determined patterns. It is rather surprising that differentiation in cell types and formation of controlled patterns are compatible, because the former gives morphogenetic diversification whereas the latter implies recursive production of a cell ensemble, reducing individual differences. We studied this problem by taking a simple cell model with intracellular reaction dynamics of chemical concentrations, cell–cell interactions, and increase in cell numbers. We observed successive differentiation from a cell type with diverse chemicals and chaotic concentration dynamics to cell types with oscillatory or fixed-point dynamics, leading to morphogenetic diversity in a spatial pattern. We further show that, by starting from an initial object consisting of both the former cell type with diverse chemicals and the latter differentiated cell type, the recursive production of a Multicellular Organism with morphogenetic diversity is possible. By relating the former type to a cell in the vegetal pole and the latter to one in the animal pole, classic experimental results with separation of blastomeres in sea urchin eggs are coherently explained, while some predictions are made for in vitro morphogenesis from embryonic stem cells.

Yoko Arakaki - One of the best experts on this subject based on the ideXlab platform.

  • The Simplest Integrated Multicellular Organism Unveiled
    2016
    Co-Authors: Yoko Arakaki, Hiroko Kawai-toyooka, Yuki Hamamura, Tetsuya Higashiyama, Akira Noga, Masafumi Hirono
    Abstract:

    Volvocine green algae represent the ‘‘evolutionary time machine’ ’ model lineage for studying Multicellularity, because they encompass the whole range of evolutionary transition of Multicellularity from unicellular Chlamydomonas to.500-celled Volvox. Multicellular volvocalean species including Gonium pectorale and Volvox carteri generally have several common morphological features to survive as integrated Multicellular Organisms such as ‘‘rotational asymmetry of cells’ ’ so that the cells become components of the individual and ‘‘cytoplasmic bridges between protoplasts in developing embryos’ ’ to maintain the species-specific form of the Multicellular individual before secretion of new extracellular matrix (ECM). However, these morphological features have not been studied in the four-celled colonial volvocine species Tetrabaena socialis that is positioned in the most basal lineage within the colonial or Multicellular volvocine greens. Here we established synchronous cultures of T. socialis and carried out immunofluorescence microscopic and ultrastructural observations to elucidate these two morphological attributes. Based on immunofluorescence microscopy, four cells of the mature T. socialis colony were identical in morphology but had rotational asymmetry in arrangement of microtubular rootlets and separation of basal bodies like G. pectorale and V. carteri. Ultrastructural observations clearly confirmed the presence of cytoplasmic bridges between protoplasts in developing embryos of T. socialis even after the formation of new flagella in each daughter protoplast within the parental ECM. Therefore, these two morphological attributes might have evolved in the common four

  • The Simplest Integrated Multicellular Organism Unveiled
    PloS one, 2013
    Co-Authors: Yoko Arakaki, Hiroko Kawai-toyooka, Yuki Hamamura, Tetsuya Higashiyama, Akira Noga, Masafumi Hirono, Bradley J. S. C. Olson, Hisayoshi Nozaki
    Abstract:

    Volvocine green algae represent the “evolutionary time machine” model lineage for studying Multicellularity, because they encompass the whole range of evolutionary transition of Multicellularity from unicellular Chlamydomonas to >500-celled Volvox. Multicellular volvocalean species including Gonium pectorale and Volvox carteri generally have several common morphological features to survive as integrated Multicellular Organisms such as “rotational asymmetry of cells” so that the cells become components of the individual and “cytoplasmic bridges between protoplasts in developing embryos” to maintain the species-specific form of the Multicellular individual before secretion of new extracellular matrix (ECM). However, these morphological features have not been studied in the four-celled colonial volvocine species Tetrabaena socialis that is positioned in the most basal lineage within the colonial or Multicellular volvocine greens. Here we established synchronous cultures of T. socialis and carried out immunofluorescence microscopic and ultrastructural observations to elucidate these two morphological attributes. Based on immunofluorescence microscopy, four cells of the mature T. socialis colony were identical in morphology but had rotational asymmetry in arrangement of microtubular rootlets and separation of basal bodies like G. pectorale and V. carteri. Ultrastructural observations clearly confirmed the presence of cytoplasmic bridges between protoplasts in developing embryos of T. socialis even after the formation of new flagella in each daughter protoplast within the parental ECM. Therefore, these two morphological attributes might have evolved in the common four-celled ancestor of the colonial volvocine algae and contributed to the further increase in cell number and complexity of the Multicellular individuals of this model lineage. T. socialis is one of the simplest integrated Multicellular Organisms in which four identical cells constitute the individual.

James W Dennis - One of the best experts on this subject based on the ideXlab platform.

Scott N Furlan - One of the best experts on this subject based on the ideXlab platform.

  • comprehensive single cell transcriptional profiling of a Multicellular Organism by combinatorial indexing
    bioRxiv, 2017
    Co-Authors: Junyue Cao, Jonathan S Packer, Vijay Ramani, Darren A Cusanovich, Chau Huynh, Ray A M Daza, Xiaojie Qiu, Choli Lee, Scott N Furlan, Frank J Steemers
    Abstract:

    Conventional methods for profiling the molecular content of biological samples fail to resolve heterogeneity that is present at the level of single cells. In the past few years, single cell RNA sequencing has emerged as a powerful strategy for overcoming this challenge. However, its adoption has been limited by a paucity of methods that are at once simple to implement and cost effective to scale massively. Here, we describe a combinatorial indexing strategy to profile the transcriptomes of large numbers of single cells or single nuclei without requiring the physical isolation of each cell (Single cell Combinatorial Indexing RNA-seq or sci-RNA-seq). We show that sci-RNA-seq can be used to efficiently profile the transcriptomes of tens-of-thousands of single cells per experiment, and demonstrate that we can stratify cell types from these data. Key advantages of sci-RNA-seq over contemporary alternatives such as droplet-based single cell RNA-seq include sublinear cost scaling, a reliance on widely available reagents and equipment, the ability to concurrently process many samples within a single workflow, compatibility with methanol fixation of cells, cell capture based on DNA content rather than cell size, and the flexibility to profile either cells or nuclei. As a demonstration of sci-RNA-seq, we profile the transcriptomes of 42,035 single cells from C. elegans at the L2 stage, effectively 50-fold "shotgun cellular coverage" of the somatic cell composition of this Organism at this stage. We identify 27 distinct cell types, including rare cell types such as the two distal tip cells of the developing gonad, estimate consensus expression profiles and define cell-type specific and selective genes. Given that C. elegans is the only Organism with a fully mapped cellular lineage, these data represent a rich resource for future methods aimed at defining cell types and states. They will advance our understanding of developmental biology, and constitute a major leap towards a comprehensive, single-cell molecular atlas of a whole animal.

  • Comprehensive single-cell transcriptional profiling of a Multicellular Organism
    Science, 2017
    Co-Authors: Junyue Cao, Jonathan S Packer, Vijay Ramani, Darren A Cusanovich, Chau Huynh, Ray A M Daza, Xiaojie Qiu, Choli Lee, Scott N Furlan
    Abstract:

    To resolve cellular heterogeneity, we developed a combinatorial indexing strategy to profile the transcriptomes of single cells or nuclei, termed sci-RNA-seq (single-cell combinatorial indexing RNA sequencing). We applied sci-RNA-seq to profile nearly 50,000 cells from the nematode Caenorhabditis elegans at the L2 larval stage, which provided >50-fold "shotgun" cellular coverage of its somatic cell composition. From these data, we defined consensus expression profiles for 27 cell types and recovered rare neuronal cell types corresponding to as few as one or two cells in the L2 worm. We integrated these profiles with whole-animal chromatin immunoprecipitation sequencing data to deconvolve the cell type-specific effects of transcription factors. The data generated by sci-RNA-seq constitute a powerful resource for nematode biology and foreshadow similar atlases for other Organisms.