The Design And Engineering Of An Artificial Protein Magnetosensor

Recent evidence suggests that birds, insects, and other animals may be able use Earth’s 50 μT magnetic field for navigation. This magnetic sense is hypothesized to be facilitated by an ocular cryptochrome (Cry): a protein containing a flavin adenine dinucleotide (FAD) and a tryptophan (Trp) triad. Upon light activation, electron transfer between the FAD and Trp forms a spin-correlated radical pair, the life time of which has been shown sensitive to mT magnetic fields. However, due to the extreme fragility of cryptochrome, studying biological magneto-sensing, has proven difficult. Currently there is no evidence that cryptochrome can sense fields as weak as Earth’s. In order to overcome these technical challenges and better understand the functional requirements for a molecular compass, we have designed a simple model system; protein maquettes. Maquettes are remarkably simple, stable and absolutely designable, man-made proteins that enable experiments not possible in cryptochrome. Here we present the biophysical characterization of a family of maquettes equipped with flavin and tryptophan. By varying the distances between the cofactors, we can explore their photo-physics and ability to generate a magnetically sensitive radical pair using transient absorption spectroscopy. Despite bearing no structural resemblance to the cryptochrome fold, these maquettes generate a flavin-tryptophan radical pair that demonstrates a magnetic field effect at fields as low as 1 mT. This observation suggests that a flavin-tryptophan radical pair is sufficient for magneto-sensing and may even sense a field as weak as Earth’s. This work offers further proof that cryptochrome could be the biological magneto-sensor opens the door to a multitude of future experiments

Signaling Pathways that Regulate Autophagic Muscle Protein Degradation in C. elegans

Protein degradation in C. elegans muscle cells is very tightly controlled by opposing signaling cascades. Excessive FGFR, low IGFR or TGF-B signaling, starvation or denervation all lead to muscle protein breakdown. Here we show that under conditions of activated FGFR, low IGFR or low TGF-B activity or mutationally hyperactived MAP kinase, soluble protein in muscle cytosol is degraded through autophagy. Degradation under these conditions is prevented by a reduction of function mutation in unc-51 (encodes Atg1 homologue), by RNAi knockdown of BEC-1 (beclin), or ATG-7 (Atg7 homologue) or by treatment with N6,N6-dimethyladenosine, a presumed inhibitor of type III PtdIns-3-kinase. We infer that the MAP kinase cascade positively regulates autophagy when the FGFR signal is too high or the IGFR signal too low . However, we have yet to identify how a MAPK signal plays into TGF-B regulation of autophagy. Protein degradation following starvation or disruption of cholinergic signaling (ACh-deficient cha-1 mutant) is not prevented by interference with autophagy, consistent with the known sensitivity to proteasome inhibitors. We have also implicated the signaling protein RSK as necessary for autophagic signaling either in parallel with or downstream of MAPK The metabolic reserve of protein in muscle can be mobilized by catabolism in response to failure of any one of a variety of signals of 'healthy' conditions. To achieve versatility and flexibility of response, muscle cells evidently use multiple proteolytic systems and regulate them independently by integrating more than one regulatory input to each degradation system

Skunk River Review Fall 1996, Vol 8

https://openspace.dmacc.edu/skunkriver/1017/thumbnail.jp

Effects of variable magma supply on mid-ocean ridge eruptions : constraints from mapped lava flow fields along the Galápagos Spreading Center

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q08014, doi:10.1029/2012GC004163.Mapping and sampling of 18 eruptive units in two study areas along the Galápagos Spreading Center (GSC) provide insight into how magma supply affects mid-ocean ridge (MOR) volcanic eruptions. The two study areas have similar spreading rates (53 versus 55 mm/yr), but differ by 30% in the time-averaged rate of magma supply (0.3 × 106 versus 0.4 × 106 m3/yr/km). Detailed geologic maps of each study area incorporate observations of flow contacts and sediment thickness, in addition to sample petrology, geomagnetic paleointensity, and inferences from high-resolution bathymetry data. At the lower-magma-supply study area, eruptions typically produce irregularly shaped clusters of pillow mounds with total eruptive volumes ranging from 0.09 to 1.3 km3. At the higher-magma-supply study area, lava morphologies characteristic of higher effusion rates are more common, eruptions typically occur along elongated fissures, and eruptive volumes are an order of magnitude smaller (0.002–0.13 km3). At this site, glass MgO contents (2.7–8.4 wt. %) and corresponding liquidus temperatures are lower on average, and more variable, than those at the lower-magma-supply study area (6.2–9.1 wt. % MgO). The differences in eruptive volume, lava temperature, morphology, and inferred eruption rates observed between the two areas along the GSC are similar to those that have previously been related to variable spreading rates on the global MOR system. Importantly, the documentation of multiple sequences of eruptions at each study area, representing hundreds to thousands of years, provides constraints on the variability in eruptive style at a given magma supply and spreading rate.This work was supported by the National Science Foundation grants OCE08–49813, OCE08–50052, and OCE08– 49711.2013-02-2

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació