New science in plain sight: Citizen scientists lead to the discovery of optical structure in the upper atmosphere.

A glowing ribbon of purple light running east-west in the night sky has recently been observed by citizen scientists. This narrow, subauroral, visible structure, distinct from the traditional auroral oval, was largely undocumented in the scientific literature and little was known about its formation. Amateur photo sequences showed colors distinctly different from common types of aurora and occasionally indicated magnetic field-aligned substructures. Observations from the Swarm satellite as it crossed the arc have revealed an unusual level of electron temperature enhancement and density depletion, along with a strong westward ion flow, indicating that a pronounced subauroral ion drift (SAID) is associated with this structure. These early results suggest the arc is an optical manifestation of SAID, presenting new opportunities for investigation of the dynamic SAID signatures from the ground. On the basis of the measured ion properties and original citizen science name, we propose to identify this arc as a Strong Thermal Emission Velocity Enhancement (STEVE).

Lengsin expression and function during zebrafish lens formation.

A zebrafish ortholog of human lengsin was identified by EST analysis of an adult lens cDNA library. During zebrafish development, lengsin transcription is first detected at 24 h post-fertilization (hpf). Immunolocalization, using polyclonal antiserum generated against a Lengsin bacterial fusion protein, detects lens-specific protein in whole-mount embryos at 30 hpf. Lengsin expression in zebrafish follows the temporal expression of the alphaA- alphaB1- and betaB1-crystallin proteins in the lens. At 72 hpf, Lengsin is localized to a subpopulation of differentiating secondary fiber cells, while no expression is detected in the lens epithelial cells or central lens fibers. In the adult lens, Lengsin is restricted to a narrow band of cortical fibers and co-localizes with actin at the lateral faces of these interdigitating cells. Stable transgenic lines, using a 3 kb lengsin genomic fragment to regulate EGFP expression, recapitulate the Lengsin temporal and spatial expression patterns. Lengsin function in zebrafish lens formation was examined by antisense morpholino-mediated translation and mRNA splice inhibition. At 72 hpf, the lengsin morphant lenses are reduced in size and exhibit separations within the cortex due to defects in secondary fiber morphogenesis. The location of the morphant lens defects correlates with the Lengsin protein localization at this age. These results demonstrate Lengsin is required for proper fiber cell differentiation by playing roles in either cell elongation or the establishment of cell interactions.

Evidence of a microtrabecular cytoskeletal lattice in glandular cells of hydrozoan planulae.

Hydrozoan planulae of Pennaria tiarella and Podocoryne carnea were processed for transmission electron microscopy using diethylene glycol distearate (DGD). The DGD functions as a removable embedding medium to produce embedment-free sections of intact planulae. Images of glandular cells obtained using embedment-free sections were compared with those from conventional Spurr-embedded sections. In unembedded sections a large number of thin anastomosing fibers were observed throughout the cytoplasm of the glandular cell. The fibers appeared to coalesce in certain areas to form thick bundles of fibers that partitioned the glandular cytoplasm into spherical compartments. The meshwork of fibers is three-dimensional and resembles a microtrabecular lattice. Mitochondria are suspended within and attached to the network of fibers, thus suggesting a cytoskeletal role of the fibers. This study documents the presence of a cytoplasmic fiber system within cells of intact invertebrate larvae.