Phospholipase Dζ Enhances Diacylglycerol Flux Into Triacylglycerol

Plant seeds are the primary source of triacylglycerols (TAG) for food, feed, fuel, and industrial applications. As TAG is produced from diacylglycerol (DAG), successful engineering strategies to enhance TAG levels have focused on the conversion of DAG to TAG. However, the production of TAG can be limited by flux through the enzymatic reactions that supply DAG. In this study, two Arabidopsis phospholipase Dζ genes (AtPLDζ1 and AtPLDζ2) were coexpressed in Camelina sativa to test whether the conversion of phosphatidylcholine to DAG impacts TAG levels in seeds. The resulting transgenic plants produced 2% to 3% more TAG as a component of total seed biomass and had increased 18:3 and 20:1 fatty acid levels relative to wild type. Increased DAG and decreased PC levels were examined through the kinetics of lipid assembly by [14C]acetate and [14C]glycerol incorporation into glycerolipids. [14C]acetate was rapidly incorporated into TAG in both wild-type and overexpression lines, indicating a significant flux of nascent and elongated acyl-CoAs into the sn-3 position of TAG. Stereochemical analysis revealed that newly synthesized fatty acids were preferentially incorporated into the sn-2 position of PC, but the sn-1 position of de novo DAG and indicated similar rates of nascent acyl groups into the Kennedy pathway and acyl editing. [14C]glycerol studies demonstrated PC-derived DAG is the major source of DAG for TAG synthesis in both tissues. The results emphasize that the interconversions of DAG and PC pools can impact oil production and composition

Chemical abundances and ages of the bulge stars in APOGEE high-velocity peaks

A cold high-velocity (HV, $\sim$ 200 km/s) peak was first reported in several Galactic bulge fields based on the APOGEE commissioning observations. Both the existence and the nature of the high-velocity peak are still under debate. Here we revisit this feature with the latest APOGEE DR13 data. We find that most of the low latitude bulge fields display a skewed Gaussian distribution with a HV shoulder. However, only 3 out of 53 fields show distinct high-velocity peaks around 200 km/s. The velocity distribution can be well described by Gauss-Hermite polynomials, except the three fields showing clear HV peaks. We find that the correlation between the skewness parameter ($h_{3}$) and the mean velocity ($\bar{v}$), instead of a distinctive HV peak, is a strong indicator of the bar. It was recently suggested that the HV peak is composed of preferentially young stars. We choose three fields showing clear HV peaks to test this hypothesis using the metallicity, [$\alpha$/M] and [C/N] as age proxies. We find that both young and old stars show HV features. The similarity between the chemical abundances of stars in the HV peaks and the main component indicates that they are not systematically different in terms of chemical abundance or age. In contrast, there are clear differences in chemical space between stars in the Sagittarius dwarf and the bulge stars. The strong HV peaks off-plane are still to be explained properly, and could be different in nature.Comment: 13 pages, 10 figures, published in ApJ. Updated to match the final ApJ published version. Minor revisions to the text and Figure

A bayesian meta-analysis of multiple treatment comparisons of systemic regimens for advanced pancreatic cancer

© 2014 Chan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: For advanced pancreatic cancer, many regimens have been compared with gemcitabine (G) as the standard arm in randomized controlled trials. Few regimens have been directly compared with each other in randomized controlled trials and the relative efficacy and safety among them remains unclear

Exotic smooth structures on 4-manifolds with zero signature

For every integer $k\geq 2$, we construct infinite families of mutually nondiffeomorphic irreducible smooth structures on the topological $4$-manifolds $(2k-1)(S^2\times S^2)$ and (2k-1)(\CP#\CPb), the connected sums of $2k-1$ copies of $S^2\times S^2$ and \CP#\CPb.Comment: 6 page

Exotic Smooth Structures on Small 4-Manifolds

Let M be either CP^2#3CP^2bar or 3CP^2#5CP^2bar. We construct the first example of a simply-connected symplectic 4-manifold that is homeomorphic but not diffeomorphic to M.Comment: 11 page

Chromatin extrusion explains key features of loop and domain formation in wild-type and engineered genomes

We recently used in situ Hi-C to create kilobase-resolution 3D maps of mammalian genomes. Here, we combine these maps with new Hi-C, microscopy, and genome-editing experiments to study the physical structure of chromatin fibers, domains, and loops. We find that the observed contact domains are inconsistent with the equilibrium state for an ordinary condensed polymer. Combining Hi-C data and novel mathematical theorems, we show that contact domains are also not consistent with a fractal globule. Instead, we use physical simulations to study two models of genome folding. In one, intermonomer attraction during polymer condensation leads to formation of an anisotropic “tension globule.” In the other, CCCTC-binding factor (CTCF) and cohesin act together to extrude unknotted loops during interphase. Both models are consistent with the observed contact domains and with the observation that contact domains tend to form inside loops. However, the extrusion model explains a far wider array of observations, such as why loops tend not to overlap and why the CTCF-binding motifs at pairs of loop anchors lie in the convergent orientation. Finally, we perform 13 genome-editing experiments examining the effect of altering CTCF-binding sites on chromatin folding. The convergent rule correctly predicts the affected loops in every case. Moreover, the extrusion model accurately predicts in silico the 3D maps resulting from each experiment using only the location of CTCF-binding sites in the WT. Thus, we show that it is possible to disrupt, restore, and move loops and domains using targeted mutations as small as a single base pair.National Science Foundation (U.S.) (Grant PHY-1427654)National Institutes of Health (U.S.) (New Innovator Award 1DP2OD008540-01)Cancer Prevention and Research Institute of Texas (Scholar Award R1304)Baylor College of Medicine (McNair Medical Institute Scholar Award)Presidential Early Career Award for Scientists and Engineer

Kepler Data Release 4 Notes

The Data Analysis Working Group have released long and short cadence materials, including FFIs and Dropped Targets for the Public. The Kepler Science Office considers Data Release 4 to provide "browse quality" data. These notes have been prepared to give Kepler users of the Multimission Archive at STScl (MAST) a summary of how the data were collected and prepared, and how well the data processing pipeline is functioning on flight data. They will be updated for each release of data to the public archive and placed on MAST along with other Kepler documentation, at http://archive.stsci.edu/kepler/documents.html. Data release 3 is meant to give users the opportunity to examine the data for possibly interesting science and to involve the users in improving the pipeline for future data releases. To perform the latter service, users are encouraged to notice and document artifacts, either in the raw or processed data, and report them to the Science Office

ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): How Do Dense Core Properties Affect the Multiplicity of Protostars?

During the transition phase from a prestellar to a protostellar cloud core, one or several protostars can form within a single gas core. The detailed physical processes of this transition, however, remain unclear. We present 1.3 mm dust continuum and molecular line observations with the Atacama Large Millimeter/submillimeter Array toward 43 protostellar cores in the Orion molecular cloud complex (λ Orionis, Orion B, and Orion A) with an angular resolution of ∼0.″35 (∼140 au). In total, we detect 13 binary/multiple systems. We derive an overall multiplicity frequency (MF) of 28% ± 4% and a companion star fraction (CSF) of 51% ± 6%, over a separation range of 300-8900 au. The median separation of companions is about 2100 au. The occurrence of stellar multiplicity may depend on the physical characteristics of the dense cores. Notably, those containing binary/multiple systems tend to show a higher gas density and Mach number than cores forming single stars. The integral-shaped filament of the Orion A giant molecular cloud (GMC), which has the highest gas density and hosts high-mass star formation in its central region (the Orion Nebula cluster), shows the highest MF and CSF among the Orion GMCs. In contrast, the λ Orionis GMC has a lower MF and CSF than the Orion B and Orion A GMCs, indicating that feedback from H ii regions may suppress the formation of multiple systems. We also find that the protostars comprising a binary/multiple system are usually at different evolutionary stages.T.L. acknowledges support from the National Natural Science Foundation of China (NSFC) through grants No. 12073061 and No. 12122307, the International Partnership Program of the Chinese Academy of Sciences (CAS) through grant No. 114231KYSB20200009, the Shanghai Pujiang Program (20PJ1415500), and science research grants from the China Manned Space Project with no. CMS-CSST-2021-B06. K.T. was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI (grant No. 20H05645). D.J. and J.d.F. are supported by NRC Canada and by NSERC Discovery Grants. C.-F.L. acknowledge grants from the Ministry of Science and Technology of Taiwan (MoST 107-2119-M-001-040-MY3 and 110-2112-M-001-021-MY3) and Academia Sinica (Investigator Award AS-IA-108-M01). This research was carried out in part at the Jet Propulsion Laboratory, which is operated by the California Institute of Technology under a contract with the National Aeronautics and Space Administration (80NM0018D0004). J.-E.L. was supported by a National Research Foundation of Korea grant funded by the Korean government (MSIT) (grant No. 2021R1A2C1011718). J.H. acknowledges the support of NSFC projects 11873086 and U1631237. This work is sponsored (in part) by the CAS, through a grant to the CAS South America Center for Astronomy in Santiago, Chile. S.-L.Q. is supported by the NSFC with grant No. 12033005. S.Z. acknowledges the support of the China Postdoctoral Science Foundation through grant No. 2021M700248. L.B. gratefully acknowledges support by the ANID BASAL projects ACE210002 and FB210003. P.S. was supported by a Grant-in-Aid for Scientific Research (KAKENHI No. 18H01259) of JSPS. V.-M.P. acknowledges support by the grant PID2020-115892GB-I00 funded by MCIN/AEI/10.13039/501100011033

An International Quiet Ocean Experiment

Author Posting. © Oceanography Society, 2011. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 24, no. 2 (2011): 174–181, doi:10.5670/oceanog.2011.37.The effect of noise on marine life is one of the big unknowns of current marine science. Considerable evidence exists that the human contribution to ocean noise has increased during the past few decades: human noise has become the dominant component of marine noise in some regions, and noise is directly correlated with the increasing industrialization of the ocean. Sound is an important factor in the lives of many marine organisms, and theory and increasing observations suggest that human noise could be approaching levels at which negative effects on marine life may be occurring. Certain species already show symptoms of the effects of sound. Although some of these effects are acute and rare, chronic sublethal effects may be more prevalent, but are difficult to measure. We need to identify the thresholds of such effects for different species and be in a position to predict how increasing anthropogenic sound will add to the effects. To achieve such predictive capabilities, the Scientific Committee on Oceanic Research (SCOR) and the Partnership for Observation of the Global Oceans (POGO) are developing an International Quiet Ocean Experiment (IQOE), with the objective of coordinating the international research community to both quantify the ocean soundscape and examine the functional relationship between sound and the viability of key marine organisms. SCOR and POGO will convene an open science meeting to gather community input on the important research, observations, and modeling activities that should be included in IQOE