Complementary transcriptomic, lipidomic, and targeted functional genetic analyses in cultured Drosophila cells highlight the role of glycerophospholipid metabolism in Flock House virus RNA replication

Abstract Background Cellular membranes are crucial host components utilized by positive-strand RNA viruses for replication of their genomes. Published studies have suggested that the synthesis and distribution of membrane lipids are particularly important for the assembly and function of positive-strand RNA virus replication complexes. However, the impact of specific lipid metabolism pathways in this process have not been well defined, nor have potential changes in lipid expression associated with positive-strand RNA virus replication been examined in detail. Results In this study we used parallel and complementary global and targeted approaches to examine the impact of lipid metabolism on the replication of the well-studied model alphanodavirus Flock House virus (FHV). We found that FHV RNA replication in cultured Drosophila S2 cells stimulated the transcriptional upregulation of several lipid metabolism genes, and was also associated with increased phosphatidylcholine accumulation with preferential increases in lipid molecules with longer and unsaturated acyl chains. Furthermore, targeted RNA interference-mediated downregulation of candidate glycerophospholipid metabolism genes revealed a functional role of several genes in virus replication. In particular, we found that downregulation of Cct1 or Cct2, which encode essential enzymes for phosphatidylcholine biosynthesis, suppressed FHV RNA replication. Conclusion These results indicate that glycerophospholipid metabolism, and in particular phosphatidylcholine biosynthesis, plays an important role in FHV RNA replication. Furthermore, they provide a framework in which to further explore the impact of specific steps in lipid metabolism on FHV replication, and potentially identify novel cellular targets for the development of drugs to inhibit positive-strand RNA viruses.http://deepblue.lib.umich.edu/bitstream/2027.42/78268/1/1471-2164-11-183.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/2/1471-2164-11-183-S3.XLShttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/3/1471-2164-11-183-S2.XLShttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/4/1471-2164-11-183.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/5/1471-2164-11-183-S4.XLShttp://deepblue.lib.umich.edu/bitstream/2027.42/78268/6/1471-2164-11-183-S1.XLSPeer Reviewe

On the barotropic planetary oscillations of the Pacific

Free linear solutions of the barotropic shallow-water equations are computed for a variety of basin shapes and topographies relevant to the Pacific Ocean. Attention is drawn to the 2-day to 6-day period band within which large-scale coherency is observed in Pacific tide-gauge records of sea level. In a particular model basin with realistic topography, the fundamental planetary mode of the Pacific occurs with a period of 3 days and four other planetary-topographic modes populate the 4–6 day period band. We argue that the frequencies and structures of these modes are representative of the largest-scale vorticity oscillations of the Pacific and may help account for the observed broad-bandedness of sea-level in the 4–6 day period band. These predictions will guide future analyses of sea-level and bottom-pressure observations from which a direct estimate of the frictional damping of barotopic Rossby waves may ultimately be obtained

Physical drivers of the summer 2019 North Pacific marine heatwave.

Summer 2019 observations show a rapid resurgence of the Blob-like warm sea surface temperature (SST) anomalies that produced devastating marine impacts in the Northeast Pacific during winter 2013/2014. Unlike the original Blob, Blob 2.0 peaked in the summer, a season when little is known about the physical drivers of such events. We show that Blob 2.0 primarily results from a prolonged weakening of the North Pacific High-Pressure System. This reduces surface winds and decreases evaporative cooling and wind-driven upper ocean mixing. Warmer ocean conditions then reduce low-cloud fraction, reinforcing the marine heatwave through a positive low-cloud feedback. Using an atmospheric model forced with observed SSTs, we also find that remote SST forcing from the central equatorial and, surprisingly, the subtropical North Pacific Ocean contribute to the weakened North Pacific High. Our multi-faceted analysis sheds light on the physical drivers governing the intensity and longevity of summertime North Pacific marine heatwaves

Eddy–wind interaction in the California Current System : dynamics and impacts

Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 439-459, doi:10.1175/JPO-D-15-0086.1.The summertime California Current System (CCS) is characterized by energetic mesoscale eddies, whose sea surface temperature (SST) and surface current can significantly modify the wind stress and Ekman pumping. Relative importance of the eddy–wind interactions via SST and surface current in the CCS is examined using a high-resolution (7 km) regional coupled model with a novel coupling approach to isolate the small-scale air–sea coupling by SST and surface current. Results show that when the eddy-induced surface current is allowed to modify the wind stress, the spatially averaged surface eddy kinetic energy (EKE) is reduced by 42%, and this is primarily due to enhanced surface eddy drag and reduced wind energy transfer. In contrast, the eddy-induced SST–wind coupling has no significant impact on the EKE. Furthermore, eddy-induced SST and surface current modify the Ekman pumping via their crosswind SST gradient and surface vorticity gradient, respectively. The resultant magnitudes of the Ekman pumping velocity are comparable, but the implied feedback effects on the eddy statistics are different. The surface current-induced Ekman pumping mainly attenuates the amplitude of cyclonic and anticyclonic eddies, acting to reduce the eddy activity, while the SST-induced Ekman pumping primarily affects the propagation. Time mean–rectified change in SST is determined by the altered offshore temperature advection by the mean and eddy currents, but the magnitude of the mean SST change is greater with the eddy-induced current effect. The demonstrated remarkably strong dynamical response in the CCS system to the eddy-induced current–wind coupling indicates that eddy-induced current should play an important role in the regional coupled ocean–atmosphere system.We thank NSF for support under GrantsOCE-0960770,OCE-1419235, andOCE-1419306. HS is grateful for the WHOI internal support from the Andrew W. Mellon Foundation Awards for Innovative Research and the additional support from the ONR We thank NSF for support under GrantsOCE-0960770,OCE-1419235, andOCE-1419306. HS is grateful for the WHOI internal support from the Andrew W. Mellon Foundation Awards for Innovative Research and the additional support from the ONR2016-05-3

Effect of eddy-wind interaction on Ekman pumping and eddy kinetic energy : a regional coupled modeling study for the California Current System

The definitive version was published in CalCOFI Reports 56 (2015): 83The California Current system (CCS) is characterized by the energetic summertime mesoscale and filamentary eddies with typical anomalies in sea surface temperature (SST) and surface current exceeding 2˚C and 0.5 cms–1, respectively. Recent satellite observations show that both SST and surface current at oceanic mesoscales significantly influence the Ekman pumping velocity, suggestive of a subsequent dynamical feedback effect on the eddy energetics. The extent to which this mesoscale coupling is important for the Ekman pumping and the eddy kinetic energy (EKE) budget in the CCS is the focus of this study

Design for the Raritan Yacht Club

Thesis (M.Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1958.Includes bibliographical references (leaf 38).by J. Arthur Miller.M.Arch

Analysis of multistory frames with light gauge steel panel infills

PREFACE This report was originally presented as a thesis to the Faculty of the Graduate School of Cornell University in partial fulfillment of the requirements for the degree of Doctor of Philosophy, conferred in August 1972. The author wishes to thank Professor Arthur H. Nilson, Project Director, and Professor Robert G. Sexsmith, Principal Investigator, for the help and guidance that made this work possible. This investigation was supported by the American Iron and Steel Institute

Coupled impacts of the diurnal cycle of sea surface temperature on the Madden–Julian oscillation

Author Posting. © American Meteorological Society, 2014. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 27 (2014): 8422–8443, doi:10.1175/JCLI-D-14-00141.1.This study quantifies, from a systematic set of regional ocean–atmosphere coupled model simulations employing various coupling intervals, the effect of subdaily sea surface temperature (SST) variability on the onset and intensity of Madden–Julian oscillation (MJO) convection in the Indian Ocean. The primary effect of diurnal SST variation (dSST) is to raise time-mean SST and latent heat flux (LH) prior to deep convection. Diurnal SST variation also strengthens the diurnal moistening of the troposphere by collocating the diurnal peak in LH with those of SST. Both effects enhance the convection such that the total precipitation amount scales quasi-linearly with preconvection dSST and time-mean SST. A column-integrated moist static energy (MSE) budget analysis confirms the critical role of diurnal SST variability in the buildup of column MSE and the strength of MJO convection via stronger time-mean LH and diurnal moistening. Two complementary atmosphere-only simulations further elucidate the role of SST conditions in the predictive skill of MJO. The atmospheric model forced with the persistent initial SST, lacking enhanced preconvection warming and moistening, produces a weaker and delayed convection than the diurnally coupled run. The atmospheric model with prescribed daily-mean SST from the coupled run, while eliminating the delayed peak, continues to exhibit weaker convection due to the lack of strong moistening on a diurnal basis. The fact that time-evolving SST with a diurnal cycle strongly influences the onset and intensity of MJO convection is consistent with previous studies that identified an improved representation of diurnal SST as a potential source of MJO predictability.The authors gratefully acknowledge support from the Office of Naval Research (N00014-13-1-0133 and N00014-13-1-0139) and National Science Foundation EaSM-3 (OCE-1419235). HS especially thanks the Penzance Endowed Fund for their support of Assistant Scientists at WHOI.2015-05-1