Genetic Relationships among Lancelet Populations in Seto Inland Sea Inferred from Mitochondrial DNA Sequences <Article>

Genetic relationships were examined among a total of 74 lancelets, Branchiostoma japonicum (Willey 1897), collected at 16 stations in the Seto Inland Sea on the basis of the sequence of the COI region of mitochondrial DNA. Genetic divergence was usually high at the stations near straits. Besides, there were no significant relationships between geographical and genetic distances of individual lancelets. As many as 62 haplotypes were recognized, among which only three comprised multiple individuals from distant stations, and the remaining ones comprised a single individual. In a dendrogram, some clusters were made up of individuals from nearby stations whereas other ones were made up of those from more or less distant stations. These results suggest that the high genetic heterogeneity of the lancelet population in the Seto Inland Sea is maintained by continuous genetic exchanges via a large-scale dispersion at long planktonic stages driven by tidal and constant currents in this region

A practical device for pinpoint delivery of molecules into multiple neurons in culture

We have developed a device for pinpoint delivery of chemicals, proteins, and nucleic acids into cultured cells. The principle underlying the technique is the flow of molecules from the culture medium into cells through a rupture in the plasma membrane made by a needle puncture. DNA transfection is achieved by stabbing the needle tip into the nucleus. The CellBee device can be attached to any inverted microscope, and molecular delivery can be coupled with conventional live cell imaging. Because the position of the needle relative to the targeted cultured cells is computer-controlled, efficient delivery of molecules such as rhodamine into as many as 100 HeLa cells can be completed in 10 min. Moreover, specific target cells within a single dish can be transfected with multiple DNA constructs by simple changes of culture medium containing different plasmids. In addition, the nano-sized needle tip enables gentle molecular delivery, minimizing cell damage. This method permits DNA transfection into specific hippocampal neurons without disturbing neuronal circuitry established in culture

Feeding Habit and Body Constituent of the Larval Red Sea Bream, Pagrus major, in the Semi-Extensive Rearing Condition

高知県栽培漁業センターの半粗放的飼育池におけるマダイ幼魚の食性と体成分を調査し、次の知見を得た。1) 飼育池でのマダイ幼魚の食性は、調査日によって天然餌料依存型と人工飼料依導型に大別され、天然餌料に依存した食性を示した群の胃充満度は、人工飼料に依存した群に比べて低い傾向にあった。2) 筋肉中の一般成分は中間育成期間中ほとんど変化しなかったが、その後は筋肉および腹腔内脂肪組織の脂質クラス組成におびてトリグリセライドの比率が著しく増加した。Stomach content and body constituent of the larval red sea bream were examined at the large pond of Kohchi Fish Farming Center. The fish was semi-extensively reared by the supply of artificial diet in addition to natural organisms and ranged from 8.2 to approximately 50 mm. 1) In the food composition, either natural organisms such as Copepoda or artificial diet was predominant at each sampling date. Stomach fullness of the fish feeding mainly on the former was higher as compared with the fish depending on the latter. 2) The proximate composition of muscle hardly changed during the rearing period. But thereafter the lipid class of muscle and intraperitoneal fat body exhibited a remarkable change, particularly an increase in the ratio of triglycerides

A Psychological Study of Teaching Practice (8)

本研究では教員養成学部生132名を対象にし，教育実習への自己効力感の程度が教育実習に対する意識，及び教職への過性感，志望度と精神的な健康状態にどのような影響を及ぼすか，また，教育実習への自己効力感の程度と教育実習の課題設定の関連を検討した。　その結果、教育実習への自己効力感の認知の程度により教職の適性感，志望度，教育実習への価値観が異なることが明らかになった。教育実習をうまく対処することや乗り越えることができるという認知は，教職への志や教師としての資質を有するという感覚が高まっていると考えられる。しかし，一方で自己効力感の程度に関係なく，多くの実習生が教育実習を不安と感じていることも明らかになった。また，教育実習の課題設定の仕方によって教職志望度が異なることが分かった。教育実習に向けての課題設定の違いや，教育実習への自己効力感の違いから精神的な健康状態も変わってくることが明らかになった