We evaluated the in vivo fate and physiological behavior of quantum dots (QDs) in Caenorhabditis elegans by GFP transfection, fluorescent imaging, synchrotron radiation based elemental imaging, and speciation techniques. The in situ metabolism and degradation of QDs in the alimentary system and long-term toxicity on reproduction are fully assessed. This work highlights the utility of the C. elegans model as a multiflexible platform to allow noninvasively imaging and monitoring in vivo consequences of engineered nanomaterials.

A, 1 1~s~) arid K. KOHRA The kinematical and dynaniical component's of diffracted X-rays from perfect and mechanically dsinsged silicon single crystals are separately measured in t.he vicinity of the reciprocal lattice point using a triple crystal arrangement of ( j -n , --n, +n) setting. I n the case of a perfect' crystal, besides the normal dynamical diffraction, a broad and weak hump due to the lattice vibration is observed a t the scattering vector deviation as small as 2 x lo3 cni-l. For crystals with lapped and scratched surface a noticeable change of the int>ensity curves, i.e. a change! of the equal-intensity coiit,our in the reciprocal space, is observed.Die kinematischen und dynamischen Komponenten der gestreuten R,ontgenstrahlen von perfekten und niechanisch gestorten Siliziumeinkrist'ailen werden in der h'ahe von reziproken Gitterpunkten mit einem Dreikristalldiffraktometer in (+n, -I $ , + n ) Anordnang gemessen. I m Fall des perfekten Kristalls wird aul3er der normalen dynaniischen Beugting, ein breit.er und schm6chere.r Bnckel der Kurve infolge der Gitterschwingung bei Abweichungen des Streuvektors von ctwa 2 x lo3 cm-1 beobacht'et. Fur Kristalle mit polierten und geritzten Oberflachen wird eine nierkliche Anderung der Intensitatskurve, namlich eine anderung der Konturen gleicher Intensitgt im reziproken Gitterraum, beobachtet.

Elucidating the morphogenetic events that shape vertebrate heart valves, complex structures that prevent retrograde blood flow, is critical to understanding valvular development and aberrations. Here, we used the zebrafish atrioventricular (AV) valve to investigate these events in real time and at single-cell resolution. We report the initial events of collective migration of AV endocardial cells (ECs) into the extracellular matrix (ECM), and their subsequent rearrangements to form the leaflets. We functionally characterize integrin-based focal adhesions (FAs), critical mediators of cell–ECM interactions, during valve morphogenesis. Using transgenes to block FA signaling specifically in AV ECs as well as loss-of-function approaches, we show that FA signaling mediated by Integrin α5β1 and Talin1 promotes AV EC migration and overall shaping of the valve leaflets. Altogether, our investigation reveals the critical processes driving cardiac valve morphogenesis in vivo and establishes the zebrafish AV valve as a vertebrate model to study FA-regulated tissue morphogenesis.

To investigate the toxicological effects of nanomaterials, experimental studies on the absorption and accumulation in organisms are of broad interest. In the present study, Caenorhabditis elegans (C. elegans) was used as a ''model'' organism to investigate the bioaccumulation and toxicological effects of engineered copper nanoparticles with a scanning technique of microbeam synchrotron radiation X-ray fluorescence (m-SRXRF). The adult hermaphrodite is anatomically simple with 959 somatic cells and 1 mm in length. The mapping results of the whole organism indicate that the exposure to copper nanoparticles can result in an obvious elevation of Cu and K levels, and a change of bio-distribution of Cu in nematodes. Accumulation of Cu occurs in the head and at a location 1/3 of the way up the body from the tail compared to the un-exposed control. In contrast, a higher amount of Cu was detected in other portion of worm body, especially in its excretory cells and intestine when exposed to Cu 2+ . The results compared well with total Cu levels in nematodes, which were 4.10 AE 0.54, 12.32 AE 0.49 and 5.22 AE 0.63 mg g À1 dry weight for the PBS, Cu 2+ and Cu nanoparticle groups, respectively, measured by ICP-MS. The nondestructive and multi-elemental m-SRXRF provides an important tool for mapping the elemental distribution in the whole body of a single tiny nematode at lower levels.

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