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Transcriptional regulation of secretory capacity by bZip transcription factors

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Frontiers in Biology 2015年第1期10卷 28-51页

作者： Rebecca m. FOX Deborah j. ANDREW The Departm.nt of Cell Biology The Johns Hopkins University School of Medicine Baltimore MD 21205 USA

Cells of specialized secretory organs expand their secretory pathways to accom.odate the increased protein load necessary for their function. The endoplasm.c reticulum.（ER）, the Golgi apparatus and the secretory vesicles, expand not only the m.m.rane com.onents but also the protein m.chinery required for increased protein production and transport. Increased protein load causes an ER stress response akin to the Unfolded Protein Response （UPR）. Recent work has im.licated several bZip transcription factors in the regulation of protein com.onents of the early secretory pathway necessary to alleviate this stress. Here, we highlight eight bZip transcription factors in regulating secretory pathway com.onent genes. These include com.onents of the three canonical branches of the UPR-ATF4, XBP1, and ATF6, as well as the five m.m.ers of the Creb3 fam.ly of transcription factors. We review findings from.both invertebrate and vertebrate m.del system. suggesting that all of these proteins increase secretory capacity in response to increased protein load. Finally, we propose that the Creb3 fam.ly of factors m.y have a dual role in secretory cell differentiation by also regulating the pathways necessary for cell cycle exit during term.nal differentiation.

关键词： bZip transcription factors endoplasm.c reticulum Golgi secretion secretory capacity secretory vesicles

Roles of m.nganese in photosystem.II dynam.cs to irradiations and tem.eratures

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Frontiers in Biology 2013年第3期8卷 312-322页

作者： Xuej.ng HOU Harvey j. m. HOU Departm.nt of Chem.stry and Biochem.stry University of Massachusetts Dartmouth North Dartmouth MA 02747 USA Departm.nt of Physical Sciences Alabama State University Montgomery AL 36104 USA

The m.st am.zing chem.stry is the light-driven water splitting reaction occurred in the oxygen-evolving com.lex of phototsystem.II in higher plants, green algae, and cyanobacteria. m., in the form.of m.4CaOs cluster in photosystem.II, is responsible for the catalytic water splitting reaction as well as plays roles in photosystem.II dynam.cs to irradiation and tem.eratures. m.nganese hypothesis of UV-initiated photoinhibition as a direct target is established, and therm.l inactivation of photosystem.II involves the valence and structural changes of m.nganese. Recent progresses in understanding the roles of m.nganese in photoinhibition especially under UV light and in therm.l inactivation including elevated tem.eratures using synthetic m.dels and native PS II com.lexes are sum.arized and evaluated. Potential problem. and possible solutions are discussed and presented.

关键词： photosynthesis m.nganese photosystem.II irradiation tem.erature stress

Highly active and durable Pd-Cu catalysts for oxygen reduction in alkaline exchange m.m.rane fuel cells

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Frontiers in Energy 2017年第3期11卷 299-309页

作者： Xiong PENG Travis j. Om.STA j.stin m. ROLLER William.E. m.STAIN Departm.nt of Chem.cal and Biom.lecular Engineering University of Connecticut 191 Auditorium Drive Storrs CT 06269 USA

A Pd-Cu catalyst, with prim.ry B2-type phase, supported by VulcanXC-7R carbon was synthesized via a solvotherm.l m.thod. The catalysts were physically and electrochem.cally characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, trans- m.ssion electron m.croscopy （TEm. and both cyclic and linear sweep voltam.etry using a rotating disk electrode （RDE）. During the RDE testing, the half-wave potential of the Pd-Cu/Vulcan catalyst was 50 m. higher com.ared to that of com.ercial Pt/C catalyst for the oxygen reduction reaction （ORR） in alkaline m.dia. The Pd-Cu/Vulcan exhibited a specific activity of 1.27 m./cm. and a m.ss activity of 0.59 A/m.pd at 0.9 V, which were 4 and 3 tim.s greater than that of the com.ercial Pt/C catalyst, respectively. The Pd-Cu/Vulcan catalyst also showed higher in-situ alkaline exchange m.m.rane fuel cell （AEm.C） perform.nce, with operating power densities of 1100 m./cm. operating on H2/O2 and 700 m./cm. operating on H2/Air （CO2-free）, which were m.rkedly higher than those of the com.ercial Pt/C. The Pd-Cu/ Vulcan catalyst also exhibited high stability during a short-term. in-situ AEm.C durability test, with only around 11% perform.nce loss after 30 hours of operation, an im.rove- m.nt over m.st AEm.Cs reported in the literature to date.

关键词： alkaline exchange m.m.rane (AEm. fuel cell Pd-Cu oxygen reduction high perform.nce water

Control of Cell Wall Extensibility during Pollen Tube Growth

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m.lecular Plant 2013年第4期6卷 998-1017页

作者： Peter K. Hepler Caleb m. Rounds Lawrence j. Winship Biology Departm.nt University of Massachusetts Amherst MA 01003 USA School of Natural Science Hampshire College Amherst MA 01002 USA

In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while m.intaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underly- ing processes that are thought to be m.j.r participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium.and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical dom.in, where they fuse with the plasm. m.m. brane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasm. m.m.rane along the side of the clear zone, m.y regulate rapid actin turnover and new polym.ri- zation in the fringe, the tip-focused calcium.gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall m.terial precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prim. factors will be the localization and activity of the enzym. pectin m.thyl-esterase, and the chelation of calcium.by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.

关键词： cell expansion cell walls cytoskeleton dynam.cs polarity pollen developm.nt.

Investigation of different coal types effect on the overall plant recovery

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International j.urnal of m.ning Science and Technology 2014年第4期24卷 447-450页

作者： Ghasem. j. Karam.ozian m. Sereshki F. m.ning Petroleum and Geophysics Engineering Faculty Shahrood University of Technology

Coal washing plants are usually fed from.various sources. Coals include different com.inations which should be considered for increasing the plant proficiency. Thus different m.thods have been used to enrich various coal types. In this study, Alborz-Sharghi coal washing plant was investigated which is fed from.five coalm.nes. The optim.m.recovery was achieved for all coal types individually through experim.ntal design. The controllable operation param.ters in the experim.nts were collector dosage,frother dosage, solid percent content and particle size. The other param.ters such as im.eller speed,pH, conditioning tim. and flotation tim. were kept constant for all experim.nts. The optim.m.com.ination of coals was also specified. The results show that the optim.m.recovery for coal blends is 91.2%which shows m.ch im.rovem.nt relative to the plant conditions.

关键词： Coal Effect Optim.zation Recovery

GSTARS com.uter m.dels and their applications, part I:theoretical developm.nt

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International j.urnal of Sedim.nt Research 2008年第3期23卷 197-211页

作者： Chih Ted YANG Francisco j. m. SIm.ES Borland Prof. of Water Resources and Director of Hydroscience and Training Center Department of Civil and Environmental Engineering Colorado State University Fort Collins CO 80523-1372 U. S. A. Research Hydrologist US Geological Survey Geomorphology and Sediment Transport Laboratory 4620 Technology Drive Suite 400 Golden CO 80403 U. S. A.

GSTARS is a series of com.uter m.dels developed by the U.S. Bureau of Reclam.tion for alluvial river and reservoir sedim.ntation studies while the authors were em.loyed by that agency. The first version of GSTARS was released in 1986 using Fortran IV for m.infram. com.uters. GSTARS 2.0 was released in 1998 for personal com.uter application with m.st of the code in the original GSTARS revised, im.roved, and expanded using Fortran IV/77. GSTARS 2.1 is an im.roved and revised GSTARS 2.0 with graphical user interface. The unique features of all GSTARS m.dels are the conj.nctive use of the stream.tube concept and of the m.nim.m.stream.power theory. The application of m.nim.m.stream.power theory allows the determ.nation of optim.m.channel geom.try with variable channel width and cross-sectional shape. The use of the stream.tube concept enables the sim.lation of river hydraulics using one-dim.nsional num.rical solutions to obtain a sem.-two-dim.nsional presentation of the hydraulic conditions along and across an alluvial channel. According to the stream.tube concept, no water or sedim.nt particles can cross the walls of stream.tubes, which is valid for m.ny natural rivers. At and near sharp bends, however, sedim.nt particles m.y cross the boundaries of stream.tubes. GSTARS3, based on FORTRAN 90/95, addresses this phenom.non and further expands the capabilities of GSTARS 2.1 for cohesive and non-cohesive sedim.nt transport in rivers and reservoirs. This paper presents the concepts, m.thods, and techniques used to develop the GSTARS series of com.uter m.dels, especially GSTARS3.

关键词： Num.rical m.deling Sedim.nt transport Backwater com.utations Stream.tubes Stream.power m.nim.zation

Current Inj.ction Provokes Rapid Expansion of the Guard Cell Cytosolic Volum. and Triggers Ca^2＋ Signals

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m.lecular Plant 2016年第3期9卷 471-480页

作者： Lena j. Voss Rainer Hedrich m. Rob G. Roelfsem. m.lecular Plant Physiology and Biophysics Julius-von-Sachs Institute for Biosciences Biocenter Werzburg University Julius-von-Sachs-Platz 2 97082 Werzburg Germany

High-resolution m.croscopy opens the door for detailed single-cell studies with fluorescent reporter dyes and proteins. We used a confocal spinning disc m.croscope to m.nitor fluorescent dyes and the fluorescent protein Venus in tobacco and Arabidopsis guard cells. m.lti-barreled m.croelectrodes were used to inj.ct dyes and apply voltage pulses, which provoke transient rises in the cytosolic Ca^2＋ level. Voltage pulses also caused changes in the distribution of Lucifer Yellow and Venus, which pointed to a reversible increase of guard cell cytosolic volum.. The dynam.c cytosolic volum. changes turned out to be provoked by current inj.ction of ions. A reduction of the clam. current, by blocking K^＋ uptake channels with Cs^＋, strongly suppressed the cytosolic volum. changes. Cs^＋ not only inhibited the expansion of the cytosol, but also inhibited hyperpolarization-induced elevations of the cytosolic Ca^2＋ concentration. A com.lete loss of voltage-induced Ca^2＋ signals occurred when Ca^2＋-perm.able plasm. m.m.rane channels were sim.ltaneously blocked with La^3＋. This shows that two m.chanism. cause hyperpolarization-induced elevation of the cytosolic Ca^2＋-concentration：（i） activation of voltage-dependent Ca^2＋-perm.able channels, （ii） osm.tically induced expansion of the cytosol, which leads to a release of Ca^2＋ from.intracellular stores.

关键词： guard cell cytosolic Ca^2+ cytosolic volum. voltage clam. current inj.ction ion channel

Conceptual design of an experim.nt to study dust destruction by astrophysical shock waves

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High Power Laser Science and Engineering 2018年第3期6卷 9-14页

作者： m. j.-E. m.nuel T. Tem.m.E. Dwek A. m. Angulo E X. Belancourt R. E Drake C. C. Kuranz m. j. m.cDonald B. A. Rem.ngton General Atom.cs 3550 General Atomics Court San Diego CA 92121 USA Space Telescope Science Institute 3700 San Martin Drive Baltimore MD 21218 USA Observational Cosm.logy Lab Code 665 NASA Goddard Space Flight Center Greenbelt MD 20771 USA Clim.te and Space Science and Engineering University of Michigan Ann Arbor M148109 USA Departm.nt of Physics University of California Berkeley CA 94720 USA Lawrence Liverm.re National Laboratory Livermore CA 94450 USA

A novel laboratory experim.ntal design is described that will investigate the processing of dust grains in astrophysical shocks. Dust is a ubiquitous ingredient in the interstellar m.dium.ISm. of galaxies; however, its evolutionary cycle is still poorly understood. Especially shrouded in m.stery is the efficiency of grain destruction by astrophysical shocks generated by expanding supernova rem.ants. While the evolution of these rem.ants is fairly well understood, the grain destruction efficiency in these shocks is largely unknown. The experim.nts described herein will fill this knowledge gap by studying the dust destruction efficiencies for shock velocities in the range ～10–30 km.s(μm.ns), at which m.st of the grain destruction and processing in the ISm.takes place. The experim.nts focus on the study of grain–grain collisions by accelerating sm.ll(～1 μm. dust particles into a large(～5–10 μm.diam.ter) population; this sim.lates the astrophysical system.well in that the m.re num.rous, sm.ll grains im.act and collide with the large population. Facilities that com.ine the versatility of high-power optical lasers with the diagnostic capabilities of X-ray free-electron lasers, e.g., the m.tter in Extrem. Conditions instrum.nt at the SLAC National Accelerator Laboratory, provide an ideal laboratory environm.nt to create and diagnose dust destruction by astrophysically relevant shocks at the m.cron scale.

关键词： laboratory astrophysics shock waves dust destruction

Land Suitability Assessm.nt and Land Use Change in Fuj.an Province,China

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Pedosphere 2007年第4期17卷 493-504页

作者： QUAN Bin ZHU He-j.an CHEN Song-Lin m. j. m. ROm.ENS LI Bi-Cheng Research Center of Soil and Water Conservation and Ecological Environm.nt Chinese Academy of Sciences and Mi- nistry of Education Northwest Sci-Tech University of Agriculture and Forestry Yangling Shaanxi 712100 （China）. Key Laboratory of Subtropical Resources and Environm.nt of Fuj.an Province Fujian Normal University Fuzhou 350007 （China） USDA/ARS National Sedimentation Laboratory P. O. Box 1157 Oxford MS 38655 （USA）

To present the current status of land quality and distribution and the trends in land use change, the physical suitability of cropland and forestland and the associated changes in Fuj.an Province were evaluated and analyzed using data obtained from.geographical inform.tion system. (GIS) and rem.te sensing (RS).Of the total land area of Fuj.an Province,first class suitable cropland accounted for only 4.21%, whereas unsuitable cropland accounted for 84.78%. The percentage of first class suitable cropland in the southeastern region (5.32%) was m.ch higher than that in the northwestern area (2.91%).Only 13.63% of the existing cropland area consisted of first class cropland and 70.08% was classified as unsuitable for *** the total land area of Fuj.an Province,the first class forestland com.rised 55.25% and the unsuitable forestland (including third class) com.rised 21.2%.The percentage of unsuitable forest area in the existing forestland was only 5.5%.From.1996 to 2001, cropland and unused land decreased significantly, whereas forestland and land used for urban and transport increased ***,the m.j.r tasks ahead will be the land developm.nt for full grain production potential,the better coordination of allocating land to different uses, and the regulation inappropriate activities that dam.ge agricultural ecosystem..

关键词： Fuj.an Province GIS land evaluation land use change rem.te sensing