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James O. Farlow,Anne Argast 한국고생물학회 2006 고생물학회지 Vol.22 No.1
미국 인다아나주 Grant County의 Pipe Creek Sinkhole (PCS)에서 산출된 화석 군집은 신제3기의 크고 작은 다양한 육상, 수상의 척추동물의 풍부한 뼈를 보존하고 있다. PCS 뼈의 속성작용을 조사하기 위해 주사전자현미경, X선 회절 분석, 에너지 분산 X선 분석 그리고 연소 후 무게 감소 측정 등 몇 가지 기술을 사용하였다. 대부분 PCS 뼈는 외부에 거의 풍화가 없다. 내부적으로도 잘 보존되어 있지만 최소한 한 개의 뼈는 피질에 박테리아의 영향을 조금 받았다는 것을 보여준다. PCS 뼈의 화학분석은 보통의 뼈와 다르지 않다. 뼈 apatite는 francolite이다. PCS 뼈는 소량의 망간과 철을 포함하는데 뼈 구멍의 대부분은 결정질로 채워져 있지는 않지만 능철광 성분으로 채워진 구멍에서는 풍부하게 나타난다. 아마도 박테리아 기원의 미세한 능철광의 “반구형” (흔히 짝을 이룸)들이 어떤 PCS 뼈의 trabecular 표면에서 풍부하게 나타난다. 능철광은 수많은 결핵체와 완전히 고화되지 않은 PCS 화석층에서 풍부하다. PCS bone apatite는 현생 뼈보다 더 큰 결정질을 보이며 Full Width Half Maximum Values of the d??₂ apatite peak는 다른 화석지의 뼈에서 보이는 것과유사하다. The fossil assemblage from the Pipe Creek Sinkhole (PCS; Grant County, Indiana, USA) preserves abundant bones from a diversity of late Neogene, large and small, terrestrial and aquatic vertebrates. We used several techniques to investigate diagenesis of PCS bones: scanning electron microscopy, X-ray diffraction analysis, energy-dispersive X-ray analysis, and measurements of bone weight loss after ignition. Most PCS bone shows little surficial weathering. Internally PCS bone is also generally well-preserved, but at least one bone shows a small amount of cortical microbial attack. The chemistry of PCS bone is not unusual for fossil bone; the bone apatite is francolite. PCS bone shows small amounts of manganese and iron, both of which occur in greater abundance in sideritic fillings of bone pores, although most large openings in PCS bone remain unfilled by crystalline material. Microscopic, sideritic "hemispberoids" (often paired), probably of bacterial origin, abundantly occur on the trabecular surfaces of some PCS bone. Siderite is also abundant in numerous nodules in the otherwise unconsolidated PCS fossiliferous deposit. PCS bone apatite shows greater crystallinity than modern bone, with Full Width Half Maximum Values ofthe d??₂ apatite peak comparable to those seen in bone from other paleontological sites.
A Mechanogenetic Toolkit for Interrogating Cell Signaling in Space and Time
Seo, Daeha,Southard, Kaden M.,Kim, Ji-wook,Lee, Hyun Jung,Farlow, Justin,Lee, Jung-uk,Litt, David B.,Haas, Thomas,Alivisatos, A. Paul,Cheon, Jinwoo,Gartner, Zev J.,Jun, Young-wook Cell Press 2016 Cell Vol. No.
<P><B>Summary</B></P> <P>Tools capable of imaging and perturbing mechanical signaling pathways with fine spatiotemporal resolution have been elusive, despite their importance in diverse cellular processes. The challenge in developing a mechanogenetic toolkit (i.e., selective and quantitative activation of genetically encoded mechanoreceptors) stems from the fact that many mechanically activated processes are localized in space and time yet additionally require mechanical loading to become activated. To address this challenge, we synthesized magnetoplasmonic nanoparticles that can image, localize, and mechanically load targeted proteins with high spatiotemporal resolution. We demonstrate their utility by investigating the cell-surface activation of two mechanoreceptors: Notch and vascular endothelial cadherin (VE-cadherin). By measuring cellular responses to a spectrum of spatial, chemical, temporal, and mechanical inputs at the single-molecule and single-cell levels, we reveal how spatial segregation and mechanical force cooperate to direct receptor activation dynamics. This generalizable technique can be used to control and understand diverse mechanosensitive processes in cell signaling.</P> <P><B>Video Abstract</B></P> <P>Display Omitted</P> <P><B>Highlights</B></P> <P> <UL> <LI> Development of a mechanogenetic single-cell perturbation approach </LI> <LI> Interrogation of the spatial, chemical, and mechanical responses of Notch receptors </LI> <LI> Identification of the roles of spatial and mechanical cues on VE-cadherin signaling </LI> <LI> Spatiotemporal and quantitative control of single-cell transcription by nanoprobes </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>