145 research outputs found
Cryptochrome mediates light-dependent magnetosensitivity in Drosophila.
No full textAlthough many animals use the Earth's magnetic field for orientation and navigation, the precise biophysical mechanisms underlying magnetic sensing have been elusive. One theoretical model proposes that geomagnetic fields are perceived by chemical reactions involving specialized photoreceptors. However, the specific photoreceptor involved in such magnetoreception has not been demonstrated conclusively in any animal. Here we show that the ultraviolet-A/blue-light photoreceptor cryptochrome (Cry) is necessary for light-dependent magnetosensitive responses in Drosophila melanogaster. In a binary-choice behavioural assay for magnetosensitivity, wild-type flies show significant naive and trained responses to a magnetic field under full-spectrum light ( approximately 300-700 nm) but do not respond to the field when wavelengths in the Cry-sensitive, ultraviolet-A/blue-light part of the spectrum (<420 nm) are blocked. Notably, Cry-deficient cry(0) and cry(b) flies do not show either naive or trained responses to a magnetic field under full-spectrum light. Moreover, Cry-dependent magnetosensitivity does not require a functioning circadian clock. Our work provides, to our knowledge, the first genetic evidence for a Cry-based magnetosensitive system in any animal
A clock shock: mouse CLOCK is not required for circadian oscillator function
No full textThe circadian clock mechanism in the mouse is composed of interlocking transcriptional feedback loops. Two transcription factors, CLOCK and BMAL1, are believed to be essential components of the circadian clock. We have used the Cre-LoxP system to generate whole-animal knockouts of CLOCK and evaluated the resultant circadian phenotypes. Surprisingly, CLOCK-deficient mice continue to express robust circadian rhythms in locomotor activity, although they do have altered responses to light. At the molecular and biochemical levels, clock gene mRNA and protein levels in both the master clock in the suprachiasmatic nuclei and a peripheral clock in the liver show alterations in the CLOCK-deficient animals, although the molecular feedback loops continue to function. Our data challenge a central feature of the current mammalian circadian clock model regarding the necessity of CLOCK:BMAL1 heterodimers for clock function
The Circadian Clock in Monarch Butterfly: A Tale of Two CRYs: A Dissertation
No full textEvery fall, Northeastern America monarch butterflies (Danaus plexippus) undergo an extraordinary migration to their overwintering site in Central Mexico. During their long migration, monarch migrants use sun compass to navigate. To maintain a southward flying direction, monarch migrants compensate for the continuously changing position of the sun by providing timing information to the compass using their circadian clock. Animal circadian clocks depend primarily on a negative transcriptional feedback loop to track time. I started my work to re-construct the monarch butterfly circadian clock negative feedback loop in cell culture, focusing on homologs of Drosophila clock genes. It turned out that in addition to a Drosophila-like cryptochrome (cry1) gene, a second mammalian-like cry2 gene exists in monarch butterflies and many other insects, except in Drosophila. The two CRYs showed distinct functions in our initial assays in cultured Drosophila Schneider 2 (S2) cells. CRY2 functions as a potent transcriptional repressor, while CRY1 is light sensitive but shows no obvious transcriptional activity. The existence of two cry genes in insects changed the Drosophila-centric view of insect circadian clock. During the course of my study, our lab obtained a monarch cell line called DpN1 cells. These cells possess a light-driven clock and contributed tremendously to the research on monarch circadian clock. Using this cell line, I provided strong evidence supporting monarch CRY2’s role as a major circadian clock repressor and identified a protein-protein protective interaction cascade underlying the CRY1-mediated resetting of the molecular oscillator in DpN1 cells. I continued my work trying to understand how insect CRY2 inhibits transcription. I provided evidence suggesting the involvement of monarch PER in promoting CRY2 nuclear entry in both S2 cells and DpN1 cells. Finally, I mapped CRY2’s transcriptional inhibitory activity onto its N-terminal domain. Collectively, my research helped to change our view of insect clocks from a Drosophila-centric standpoint to a much more diverse picture. My studies also advanced the understanding of monarch circadian clock mechanism, and provides a foundation for further studies.Neuroscienc
Anatomical basis of sun compass navigation II: The neuronal composition of the central complex of the monarch butterfly
No full textCo-author Jeremy Florman is a doctoral student in the Alkema Lab and the Neuroscience Program in the Morningside Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.Each fall, eastern North American monarch butterflies in their northern range undergo a long-distance migration south to their overwintering grounds in Mexico. Migrants use a time-compensated sun compass to determine directionality during the migration. This compass system uses information extracted from sun-derived skylight cues that is compensated for time of day and ultimately transformed into the appropriate motor commands. The central complex (CX) is likely the site of the actual sun compass, because neurons in this brain region are tuned to specific skylight cues. To help illuminate the neural basis of sun compass navigation, we examined the neuronal composition of the CX and its associated brain regions. We generated a standardized version of the sun compass neuropils, providing reference volumes, as well as a common frame of reference for the registration of neuron morphologies. Volumetric comparisons between migratory and nonmigratory monarchs substantiated the proposed involvement of the CX and related brain areas in migratory behavior. Through registration of more than 55 neurons of 34 cell types, we were able to delineate the major input pathways to the CX, output pathways, and intrinsic neurons. Comparison of these neural elements with those of other species, especially the desert locust, revealed a surprising degree of conservation. From these interspecies data, we have established key components of a conserved core network of the CX, likely complemented by species-specific neurons, which together may comprise the neural substrates underlying the computations performed by the CX. (c) 2012 Wiley Periodicals, Inc.Neuroscienc
Processing of Li7La3Zr2O12 electrolyte for all solid state batteries
No full textProcessing of Li7La3Zr2O12 electrolyte for all solid state batteriesT. Reppert, C.-L. Tsai, E.-M. Hammer, M. Finsterbusch, S. Uhlenbruck, O. Guillon, M. Bram.Institute of Energy and Climate Research (IEK-1), Forschungszentrum Jülich GmbH, D-52425 JülichAll solid state lithium ion batteries (ASB) are, in comparison to conventional Lithium ion batteries (LIB) which using organic liquids, much safer due to their non-flammable property. Oxide ceramic lithium ion conductors such as Li7La3Zr2O12 (LLZ) [1] have the advantage of inertness against oxygen, stability against lithium metal, wide electrochemical window (8V vs. Li/Li+), which makes it as one of the most promising candidates for all solid state battery application. It had been reported that garnet structured LLZ has a tetragonal and cubic phase, for which cubic generally exhibit higher Li+ ion conductivity (σ ≈ 10-4 S cm-1) [2]. The substitution of Al [2], Ta [3] and Y [4] to different sites in the LLZ structure can be used to stabilize the material in its cubic phase at room temperature. However, to bridge between lab works and real application, large size LLZ functional layers need to be fabricated by different established technologies. The investigated materials have therefore been used for slurry development, processing by tape casting and sintering studies in order to obtain highly dense films. References:[1] Murugan et al., Angew. Chem. Int. Ed. 46 (2007) 7778.[2] Hubaud et al., J. Mater. Chem. A. 1 (2013) 8813. [3] Buschmann et al., Phys. Chem. Chem. Phys. 13 (2011) 19378.[4] Murugan et. al., Electrochem. Commun. 13 (2011) 1373
Posttranslational mechanisms regulate the mammalian circadian clock
No full textWe have examined posttranslational regulation of clock proteins in mouse liver in vivo. The mouse PERIOD proteins (mPER1 and mPER2), CLOCK, and BMAL1 undergo robust circadian changes in phosphorylation. These proteins, the cryptochromes (mCRY1 and mCRY2), and casein kinase I epsilon (CKI) form multimeric complexes that are bound to DNA during negative transcriptional feedback. CLOCK:BMAL1 heterodimers remain bound to DNA over the circadian cycle. The temporal increase in mPER abundance controls the negative feedback interactions. Analysis of clock proteins in mCRY-deficient mice shows that the mCRYs are necessary for stabilizing phosphorylated mPER2 and for the nuclear accumulation of mPER1, mPER2, and CKI. We also provide in vivo evidence that casein kinase I delta is a second clock relevant kinase
Wills, Surnames P-S
No full textJoseph Polk (1857); (Missing: Angelo Paresce 1863); James Perron (1876: note - includes ALS from Perron re will); (Missing: Francis P. Powers 1895); John B. Pittar (1899); George A. Pettit (1900); (Missing: Orestes Pinamonti 1901); John Pedri (1901); (Missing: Michael A. Purtell 1902); Wm. O'B. Pardow (1904); (Missing: Stanislaus Palermo 1905); Maurice E. Prendergast (1905); (Missing: Joseph J. Prendergast 1905); John B. Pittar (1905); Albert R. Peters (1905); (Missing: Stephen Power 1907, Hector Papi 1908, John F. Quirk 1895, George E. Quin 1905, Wm. J. Quigley 1905, Daniel J. Quinn 1906); Patrick Quill (1906); Aloys Roth (1857); Ernest Reiter (1860); Anthony Romano (1859); Michael Redmond (1860); Edward F. Roch (1900); Wm. J. Richley (1895); (Missing: J. Havens Richards 1896, Claudius Ramaz 1895, Em. S. Reppert 1899, Joseph Rockwell 1900); Edward W. Raymond (1901); L. Eugene Ryan (1903); (Missing: David J. Roche 1904, Charles N. Raley 1904, Claudius Ramaz 1896); John J. Ryan (1905); Aloysius Romano (1905); Thomas A. Reid (1905); (Missing: Charles J. Romage 1905, Joseph M. Renaud 1905); John J. Rodock (1906); R. Ernest Ryan (1906); Fernand A. Rousseau (1906); John J. Regan (1907); (Missing: Joseph H. Rampspacker 1909, Charles H. Stonestreet 1852, J.C. Shaw 1851); James Strain (1863); Charles H. Stonestreet 1878; Edward J. Sourin (1885); James L. Smith (1895); (Missing: Joseph M. Stadelman 1898, Edward Spillane 1898); Joseph V. Schmidt (1898); (Missing: Ferdinand Stengel 1898, Francis A. Smith 1887, Charles Steiner 1898, Joseph H. Smith 1901); Wm. S. Singleton (1901); (Missing: Martin J. Scott 1902, James Slicer 1902, Terence J. Shealy 1903); Thomas M. Sheerin (1905); (Missing: Wm. J. Stanton 1905); Wm. J. Scanlan (1905); (Missing: Henry J. Shandelle 1906); John P.M. Schleuter (1906); John Scully (1906); John B. Schmandt (1908); Patrick Sullivan (1909); (Missing: Francis C. Schroen 1909, Robert Schwickerath 1909).**Former finding aid locations: 119_80_3; 310P*
Time series of accumulation measurements from stake farm Neumayer II, Ekström Ice Shelf, Antarctica, March 1992 - 2009
No full textThis publication series contains the accumulation measurements from stake farm Neumayer II on the Ekström Ice Shelf, Antarctica. The stake farm (70°39'31''S, 8°15'9W), has been in operation since March 1992. It consists of 25 poles (balise), placed in a grid of 5 x 5 with 10 m spacing. Readings have been carried out in approx. weekly intervals by the overwintering staff. Each data set in the series contains all measurements of each stake from one calendar year in a tsv file, the average accumulation of the stake farm for each measurement and the standard deviation of the stake farm for each measurement. The data sets are accompanied by figures illustrating the development of the cumulative accumulation since the beginning of the measurements to date, a bar chart of the monthly accumulation for the year and a collection of panels (one panel per measurement) illustrating the variation of accumulation within the stake farm
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