Physiological characterization of a glacier living cyanobacterium, Phormidesmis priestleyi culture strain

The Tenth Symposium on Polar Science/Ordinary sessions : [OB] Polar Biology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

The lichens around the South Pole Syowa Station

The Tenth Symposium on Polar Science/Ordinary sessions : [OB] Polar Biology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Photosynthetic responses to water and light of five Arctic lichens and their photobionts

第3回極域科学シンポジウム/第34回極域生物シンポジウム 11月27日（火） 国立極地研究所 ３階ラウン

Insights into the mechanism of diurnal variations in methane emission from the stem surfaces of Alnus japonica

木の中にガスパイプライン？ --ガス漏れの場所を特定せよ！--. 京都大学プレスリリース. 2022-07-15.Recent studies have suggested that in certain environments, tree stems emit methane (CH₄). This study explored the mechanism of CH₄ emission from the stem surfaces of Alnus japonica in a riparian wetland. Stem CH₄ emission rates and sap flux were monitored year-round, and fine-root anatomy was investigated. CH₄ emission rates were estimated using a closed-chamber method. Sap flux was measured using Granier-type thermal dissipation probes. Root anatomy was studied using both optical and cryo-scanning electron microscopy. CH₄ emissions during the leafy season exhibited a diurnally changing component superimposed upon an underlying continuum in which the diurnal variation was in phase with sap flux. We propose a model in which stem CH₄ emission involves at least two processes: a sap flux-dependent component responsible for the diurnal changes, and a sap flux-independent component responsible for the background continuum. The contribution ratios of the two processes are season-dependent. The background continuum possibly resulted from the diffusive transport of gaseous CH₄ from the roots to the upper trunk. Root anatomy analysis indicated that the intercellular space of the cortex and empty xylem cells in fine roots could serve as a passageway for transport of gaseous CH₄

Percoll ミツド コウバイ ヲ モチイタ エンシンブンリ ニヨル イシクラゲ ノ サイボウガイタトウ (EPS) ジョキョ サイボウ ノ タンリホウ

陸生ラン色細菌のイシクラゲ(Nostoc commune)は南極や日本にも生育する汎存種である.イシクラゲの細胞の周りに存在する細胞外多糖(EPS)は,水分保持や細胞の保護に役立つと共に遮光性物質を蓄積しており,これが苛酷な環境への適応に重要な役割を果たしていると考えられている.南極産の貴重なイシクラゲを材料にしてこの仮説を検証するためには,EPSを除去した細胞を高収率で回収する必要がある.そこで,これまでに報告のあるEPS除去方法を改良し,Percollを用いた遠心分離で細胞の回収率向上を図った. その結果, イシクラゲ破砕懸濁液に10%濃度のPercollを混合して遠心することでEPSを効率良く除去できることが分かった.更に細胞画分を80% と50% のPercoll に上層して遠心することで他の不純物の除去が達成され,少量のイシクラゲを生理学実験に用いるのに適した細胞単離法が確立された.The terrestrial cyanobacterium Nostoc commune Vaucher ex Bornet et Flahault occurs worldwide, including in Japan and Antarctica. N. commune has a large amount of extracellular polysaccharides (EPS) that hold moisture and protect the cells and at the same time accumulate light-blocking substances which is believed to play an important part in adaptation to a severe environment. To evaluate the photoadaptation processes in N. commune and clarify the role(s) of EPS under ambient environmental condition at Antarctica, separation of cells from EPS is necessary. High yield is a prerequisite for the use of only small amount of natural N. commune from Antarctica. For this purpose, we developed a separation method by improving the Percoll density gradient centrifugation method using an EPS-coated field-grown Nostoc population. We established the most suitable condition to separate naked cells from EPS at high yield retaining high photosynthetic activity. The method is composed of centrifugation of cell homogenated N. commune in 10% (v/v) Percoll to separate cells efficiently from EPS followed by fractionating centrifugation to remove impurities using the gradient of Percoll (80% and 50%, v/v)

Proteolytic bacteria isolated from freshwater lakes in Antarctica

第6回極域科学シンポジウム[OB] 極域生物圏11月16日（月）　国立極地研究所１階交流アトリウ

Lichen assist the drought-induced NPQ of their photobiont by arabitol

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月18日（金） 統計数理研究所 3階リフレッシュフロ