Background Bacteria have been reported to exhibit complicated morphological colony patterns on solid media, depending on intracellular, and extracellular factors such as motility, cell propagation, and cell-cell interaction. We isolated the filamentous cyanobacterium, Pseudanabaena sp. NIES-4403 (Pseudanabaena, hereafter), that forms scattered (discrete) migrating colonies on solid media. While the scattered colony pattern has been observed in some bacterial species, the mechanism underlying such a pattern still remains obscure. Results We studied the morphology of Pseudanabaena migrating collectively and found that this species forms randomly scattered clusters varying in size and further consists of a mixture of comet-like wandering clusters and disk-like rotating clusters. Quantitative analysis of the formation of these wandering and rotating clusters showed that bacterial filaments tend to follow trajectories of previously migrating filaments at velocities that are dependent on filament length. Collisions between filaments occurred without crossing paths, which enhanced their nematic alignments, giving rise to bundle-like colonies. As cells increased and bundles aggregated, comet-like wandering clusters developed. The direction and velocity of the movement of cells in comet-like wandering clusters were highly coordinated. When the wandering clusters entered into a circular orbit, they turned into rotating clusters, maintaining a more stable location. Disk-like rotating clusters may rotate for days, and the speed of cells within a rotating cluster increases from the center to the outmost part of the cluster. Using a mathematical modeling with simplified assumption we reproduced some features of the scattered pattern including migrating clusters. Conclusion Based on these observations, we propose that Pseudanabaena forms scattered migrating colonies that undergo a series of transitions involving several morphological patterns. A simplified model is able to reproduce some features of the observed migrating clusters.

In this study, morphological and immunohistochemical alterations of skeletal muscle tissues during persistent contraction were examined by in vivo cryotechnique (IVCT). Contraction of gastrocnemius muscles was induced by sciatic nerve stimulation. The IVCT was performed immediately, 3 min or 10 min after the stimulation start. Prominent ripples of muscle fibers or wavy deformation of sarcolemma were detected immediately after the stimulation, but they gradually diminished to normal levels during the stimulation. The relative ratio of sarcomere and A band lengths was the highest in the control group, but it immediately decreased to the lowest level and then gradually recovered at 3 min or 10 min. Although histochemical intensity of PAS reaction was almost homogeneous in muscle tissues of the control group or immediately after the stimulation, it decreased at 3 min or 10 min. Serum albumin was immunolocalized as dot-like patterns within some muscle fibers at 3 min stimulation. These patterns became more prominent at 10 min, and the dots got larger and saccular in some sarcoplasmic regions. However, IgG1 and IgM were immunolocalized in blood vessels under nerve stimulation conditions. Therefore, IVCT was useful to capture the morphofunctional and metabolic changes of heterogeneous muscle fibers during the persistent contraction.

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The change of spectra of DEPC liposome with temperature and xenon pressure was observed by microscopic Raman spectroscopy to identify the phase transition of liposome. At atmospheric pressure, DEPC liposome transforms from gel to liquid crystal at approximately 12oC and shifts to lower temperature at xenon pressure. The Raman spectra indicated the slight change of C-H stretching modes at the phase transition temperature under xenon pressure. These findings support the previously obtained results by MD simulations, which showed the evidence of xenon dissolved in the lipid bilayer. Based on these observations, the Raman spectra of neurons under low temperature and xenon pressure were observed. Human induced pluripotent stem cell (hiPSC)-derived neurons may be effectively used for drug discovery and cell-based therapy. However, the immaturity of cultured human iPSC-derived neurons and the lack of established functional evaluation methods are problematic. We here used a multi-electrode array (MEA) system to investigate the effects of the coculture of rat astrocytes with hiPSC-derived neurons on the long-term culture, spontaneous firing activity, and drug responsiveness effects. The co-culture facilitated the long-term culture of hiPSC-derived neurons for >3 months and long-term spontaneous firing activity was also observed. As a result, The co-culturing with rat astrocytes allowed hiPSC-derived neurons to maintain long time spontaneous activity. We have analyzed colony-pattern formations in the multicellular (filamentous) cyanobacterium, Pseudanabaena sp. ILC 545, which we isolated previously. ILC 545 strain glides their major axis. As the bacterial density increases, we observed various colony patterns, due to collisions and entanglement. These colony patterns can be classified into three groups: "bundle" colonies with nematic alignment, "comet-like" colonies with fast population movement, and "disk" colonies forming vortices. We focused on the comet-like colony formation. Concretely we analyzed the relationship between colony size and speed, and movement of one filament in the colony. Here, we repot a model on the morphogenesis of comet-like colony formation, and some related quantitative analyses. 3P230 局所熱パルス法による神経細胞のカルシウム放出の誘導 3P234Analysis on colony formation in a filamentous cyanobacterium with an extended self-driven particle model with a cellular automaton method

Background Bacteria have been reported to exhibit complicated morphological colony patterns on solid media, depending on intracellular, and extracellular factors such as motility, cell propagation, and cell-cell interaction. We isolated the filamentous cyanobacterium, Pseudanabaena sp. NIES-4403 (Pseudanabaena, hereafter), that forms scattered (discrete) migrating colonies on solid media. While the scattered colony pattern has been observed in some bacterial species, the mechanism underlying such a pattern still remains obscure. Results We studied the morphology of Pseudanabaena migrating collectively and found that this species forms randomly scattered clusters varying in size and further consists of a mixture of comet-like wandering clusters and rotating disks. Quantitative analysis of the formation of these wandering and rotating clusters showed that bacterial filaments tend to follow trajectories of previously migrating filaments at velocities that are dependent on filament length. Collisions between filaments occurred without crossing paths, which enhanced their nematic alignments, giving rise to bundle-like colonies. As cells increased and bundles aggregated, comet-like wandering clusters developed. The direction and velocity of the movement of cells in comet-like wandering clusters were highly coordinated. When the wandering clusters entered into a circular orbit, they turned into rotating disks, maintaining a more stable location. Disks may rotate for days, and the speed of cells within a rotating disk increases from the center to the outmost part of the disk. Using a minimal agent-based model, we reproduced some features of Pseudanabaena migrating clusters. Conclusion Based on these observations, we propose that Pseudanabaena forms scattered migrating colonies that undergo a series of transitions involving several morphological patterns. A minimal agent-based model is able to reconstruct some features of the observed migrating clusters.