Dust charging processes in the nonequilibrium dusty plasma with nonextensive power-law distribution

The dust charging processes in the collections of electrons and ions in the nonequilibrium dusty plasma with power-law distributions are investigated on the basic of a new q-distribution function theory in nonextensive statistics. Electrons and ions obey the power-law distributions and are with q-parameters different from each other. We derive the generalized formulae for the dust charging currents in which the nonextensive effects play roles. Further we investigate the dust charging processes taking place in the homogeneous dusty plasma where only the particle velocities are power-law distributions and in the dust cloud plasma where the particle velocities and densities are both power-law distributions. By numerical analyses, we show that the nonextensive power-law distributions of electrons and ions have significant effects on the dust charging processes in the nonequilibrium dusty plasma.Comment: 16 pages, 6 figures, 51 reference

Dust-acoustic waves and stability in the permeating dusty plasma: I. Maxwellian distribution

The dust-acoustic waves and their stability in the permeating dusty plasma with the Maxwellian velocity distribution are investigated. We derive the dust-acoustic wave frequency and instability growth rate in two limiting physical cases that the thermal velocity of the flowing dusty plasma is (a) much larger than, and (b) much smaller than the phase velocity of the waves. We find that the stability of the waves depend strongly on the velocity of the flowing dusty plasma in the permeating dusty plasma. The numerical analyses are made based on the example that a cometary plasma tail is passing through the interplanetary space plasma. We show that, in case (a), the waves are generally unstable for any flowing velocity, but in case (b), the waves become unstable only when the wave number is small and the flowing velocity is large. When the physical conditions are between these two limiting cases, we gain a strong insight into the dependence of the stability criterions on the physical conditions in the permeating dusty plasma.Comment: 16 pages, 4 figures, 35 reference

Triacylglycerol synthesis by PDAT1 in the absence of DGAT1 activity is dependent on re-acylation of LPC by LPCAT2

<p>Abstract</p> <p>Background</p> <p>The <it>Arabidopsis thaliana dgat1 </it>mutant, <it>AS11</it>, has an oil content which is decreased by 30%, and a strongly increased ratio of 18:3/20:1, compared to wild type. Despite lacking a functional DGAT1, <it>AS11 </it>still manages to make 70% of WT seed oil levels. Recently, it was demonstrated that in the absence of <it>DGAT1</it>, <it>PDAT1 </it>was essential for normal seed development, and is a dominant determinant in <it>Arabidopsis </it>TAG biosynthesis.</p> <p>Methods</p> <p>Biochemical, metabolic and gene expression studies combined with genetic crossing of selected <it>Arabidopsis </it>mutants have been carried out to demonstrate the contribution of <it>Arabidopsis </it>PDAT1 and LPCAT2 in the absence of DGAT1 activity.</p> <p>Results</p> <p>Through microarray and RT-PCR gene expression analyses of <it>AS11 </it>vs. WT mid-developing siliques, we observed consistent trends between the two methods. <it>FAD2 </it>and <it>FAD3 </it>were up-regulated and <it>FAE1 </it>down-regulated, consistent with the <it>AS11 </it>acyl phenotype. <it>PDAT1 </it>expression was up-regulated by <it>ca </it>65% while <it>PDAT2 </it>expression was up-regulated only 15%, reinforcing the dominant role of <it>PDAT1 </it>in <it>AS11 </it>TAG biosynthesis. The expression of <it>LPCAT2 </it>was up-regulated by 50-75%, while <it>LPCAT1 </it>expression was not significantly affected. <it>In vitro </it>LPCAT activity was enhanced by 75-125% in microsomal protein preparations from mid-developing <it>AS11 </it>seed <it>vs </it>WT. Co-incident homozygous knockout lines of <it>dgat1</it>/<it>lpcat2 </it>exhibited severe penalties on TAG biosynthesis, delayed plant development and seed set, even with a functional PDAT1; the double mutant <it>dgat1/lpcat1 </it>showed only marginally lower oil content than <it>AS11</it>.</p> <p>Conclusions</p> <p>Collectively, the data strongly support that in <it>AS11 </it>it is <it>LPCAT2 </it>up-regulation which is primarily responsible for assisting in PDAT1-catalyzed TAG biosynthesis, maintaining a supply of PC as co-substrate to transfer <it>sn</it>-2 moieties to the <it>sn</it>-3 position of the enlarged <it>AS11 </it>DAG pool.</p

Hybrid hierarchical patterns of gold nanoparticles and poly(ethylene glycol) microstructures

Hybrid surface micro-patterns composed of topographic structures of polyethylene glycol (PEG)-hydrogels and hierarchical lines of gold nanoparticles (Au NPs) were fabricated on silicon wafers. Micro-sized lines of Au NPs were first obtained on the surface of a silicon wafer via &ldquo;micro-contact deprinting&rdquo;, a method recently developed by our group. Topographic micro-patterns of PEG, of both low and high aspect ratio (AR up to 6), were then aligned on the pre-patterned surface via a procedure adapted from the soft lithographic method MIMIC (Micro-Molding in Capillaries), which is denoted as &ldquo;adhesive embossing&rdquo;. The result is a complex surface pattern consisting of alternating flat Au NP lines and thick PEG bars. Such patterns provide novel model surfaces for elucidating the interplay between (bio)chemical and physical cues on cell behavior

Genomic and Metabolomic Analysis of the Potato Common Scab Pathogen Streptomyces scabiei

Streptomyces scabiei is a key causative agent of common scab disease, which causes significant economic losses to potato growers worldwide. This organism produces several phytotoxins that are known or suspected to contribute to host–pathogen interactions and disease development; however, the full metabolic potential of S. scabiei has not been previously investigated. In this study, we used a combined metabolomic and genomic approach to investigate the metabolites that are produced by S. scabiei. The genome sequence was analyzed using antiSMASH and DeepBGC to identify specialized metabolite biosynthetic gene clusters. Using untargeted liquid chromatography-coupled tandem mass spectrometry (LC-MS2), the metabolic profile of S. scabiei was compared after cultivation on three different growth media. MS2 data were analyzed using Feature-Based Molecular Networking and hierarchical clustering in BioDendro. Metabolites were annotated by performing a Global Natural Products Social Molecular Networking (GNPS) spectral library search or using Network Annotation Propagation, SIRIUS, MetWork, or Competitive Fragmentation Modeling for Metabolite Identification. Using this approach, we were able to putatively identify new analogues of known metabolites as well as molecules that were not previously known to be produced by S. scabiei. To our knowledge, this study represents the first global analysis of specialized metabolites that are produced by this important plant pathogen

The ADP receptor P2RY12 regulates osteoclast function and pathologic bone remodeling

The adenosine diphosphate (ADP) receptor P2RY12 (purinergic receptor P2Y, G protein coupled, 12) plays a critical role in platelet aggregation, and P2RY12 inhibitors are used clinically to prevent cardiac and cerebral thrombotic events. Extracellular ADP has also been shown to increase osteoclast (OC) activity, but the role of P2RY12 in OC biology is unknown. Here, we examined the role of mouse P2RY12 in OC function. Mice lacking P2ry12 had decreased OC activity and were partially protected from age-associated bone loss. P2ry12(–/–) OCs exhibited intact differentiation markers, but diminished resorptive function. Extracellular ADP enhanced OC adhesion and resorptive activity of WT, but not P2ry12(–/–), OCs. In platelets, ADP stimulation of P2RY12 resulted in GTPase Ras-related protein (RAP1) activation and subsequent α(IIb)β(3) integrin activation. Likewise, we found that ADP stimulation induced RAP1 activation in WT and integrin β(3) gene knockout (Itgb3(–/–)) OCs, but its effects were substantially blunted in P2ry12(–/–) OCs. In vivo, P2ry12(–/–) mice were partially protected from pathologic bone loss associated with serum transfer arthritis, tumor growth in bone, and ovariectomy-induced osteoporosis: all conditions associated with increased extracellular ADP. Finally, mice treated with the clinical inhibitor of P2RY12, clopidogrel, were protected from pathologic osteolysis. These results demonstrate that P2RY12 is the primary ADP receptor in OCs and suggest that P2RY12 inhibition is a potential therapeutic target for pathologic bone loss