bluuebunny/crossref_metadata_2025 huggingface dataset:
Trichloroethylene: Parkinsonism and complex 1 mitochondrial neurotoxicity
Authors: Gash Don M. , Rutland Kathryn , Hudson Naomi L. , Sullivan Patrick G. , Bing Guoying , Cass Wayne A. , Pandya Jignesh D. , Liu Mei , Choi Dong‐Yong , Hunter Randy L. , Gerhardt Greg A. , Smith Charlie D. , Slevin John T. , Prince T. Scott
Published: December 2007

Objective

To analyze a cluster of 30 industrial coworkers with Parkinson's disease and parkinsonism subjected to long‐term (8–33 years) chronic exposure to trichloroethylene.

Methods

Neurological evaluations were conducted on the 30 coworkers, including a general physical and neurological examination and the Unified Parkinson's Disease Rating Scale. In addition, fine motor speed was quantified and an occupational history survey was administered. Next, animal studies were conducted to determine whether trichloroethylene exposure is neurotoxic to the nigrostriatal dopamine system that degenerates in Parkinson's disease. The experiments specifically analyzed complex 1 mitochondrial neurotoxicity because this is a mechanism of action of other known environmental dopaminergic neurotoxins.

Results

The three workers with workstations adjacent to the trichloroethylene source and subjected to chronic inhalation and dermal exposure from handling trichloroethylene‐soaked metal parts had Parkinson's disease. Coworkers more distant from the trichloroethylene source, receiving chronic respiratory exposure, displayed many features of parkinsonism, including significant motor slowing. Neurotoxic actions of trichloroethylene were demonstrated in accompanying animal studies showing that oral administration of trichloroethylene for 6 weeks instigated selective complex 1 mitochondrial impairment in the midbrain with concomitant striatonigral fiber degeneration and loss of dopamine neurons.

Interpretation

Trichloroethylene, used extensively in industry and the military and a common environmental contaminant, joins other mitochondrial neurotoxins, MPTP (1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine) and some pesticides, as a risk factor for parkinsonism. Ann Neurol 2007
Neuropathological basis of magnetic resonance images in aging and dementia
Authors: Jagust William J. , Zheng Ling , Harvey Danielle J. , Mack Wendy J. , Vinters Harry V. , Weiner Michael W. , Ellis William G. , Zarow Chris , Mungas Dan , Reed Bruce R. , Kramer Joel H. , Schuff Norbert , DeCarli Charles , Chui Helena C.
Published: December 2007

Objective

Magnetic resonance (MR) imaging is used widely for assessment of patients with cognitive impairment, but the pathological correlates are unclear, especially when multiple pathologies are present.

Methods

This report includes 93 subjects from a longitudinally followed cohort recruited for the study of Alzheimer's disease (AD) and subcortical cerebrovascular disease (CVD). MR images were analyzed to quantify cortical gray matter volume, hippocampal volume, white matter hyperintensities, and lacunes. Neuropathological examination quantified CVD parenchymal pathology, AD pathology (defined as Consortium to Establish a Registry for Alzheimer's Disease scores and Braak and Braak stage), and hippocampal sclerosis. Subjects were pathologically classified as 12 healthy control subjects, 46 AD, 14 CVD, 9 mixed AD/CVD, and 12 cognitively impaired patients without significant AD/CVD pathology. Multivariate models tested associations between magnetic resonance and pathological findings across the entire sample.

Results

Pathological correlates of cortical gray matter volume were AD, subcortical vascular pathology, and arteriosclerosis. Hippocampal volume was related to AD pathology and hippocampal sclerosis, and the effects of hippocampal sclerosis were greater for subjects with low levels of AD pathology. White matter hyperintensities were related to age and to white matter pathology. Number of MRI lacunes was related to subcortical vascular pathology.

Interpretation

In this clinical setting, the presence of lacunes and white matter changes provide a good signal for vascular disease. The neuropathological basis of MR defined cerebral cortical and hippocampal atrophy in aging and dementia is complex, with several pathological processes converging on similar brain structures that mediate cognitive decline. Ann Neurol 2008
Dyeability improvement of polyester pretreated with some alkoxides
Authors: Bendak A. , Raslan W. M.
Published: December 2007

The influence of some alkoxides in alcoholic media, having various dielectric constants, on the physical and mechanical properties was thoroughly studied in a previous work to attain silk‐like polyester fibers. In this investigation, the dyeability behavior of this silk‐like polyester is tried. Both immersion and padding techniques are applied in the treatment. The dyeability of the pretreated polyester fabric with disperse dyes shows some progressive improvements with lowering the dyeing temperature and/or decreasing the time of dyeing attained. Ethoxide is found to be more effective in enhancing the dyeability of polyester fabric than either methoxide or propoxide. Dyeing of the pretreated polyester fabric at the boil without using carriers or conducting high temperature/high pressure dyeing is also possible. Washing and crocking fastness are relatively enhanced. Physicochemical investigations of the dyeing process and a mathematical analysis for evenness are given. A decrease in the half dyeing time and an increase in the rate of dyeing of the pretreated polyester as compared with the untreated one are noticed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Surface modification of ultra high modulus polyethylene fibers by an atmospheric pressure plasma jet
Authors: Wang T. , Wang C. , Qiu Y.
Published: December 2007

To improve their adhesion properties, ultra high modulus polyethylene (UHMPE) fibers were treated by an atmospheric pressure helium plasma jet (APPJ), which was operated at radio frequency (13.56 MHz). The surface properties of the fibers were investigated by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and contact angle measurement. The surface dyeability improvement after plasma treatments was investigated using laser scanning confocal microscopy (LSCM). The adhesion strengths of the fibers with epoxy were evaluated by microbond tests. In addition, the influence of operational parameters of the plasma treatment including power input and treatment temperature was studied. XPS analysis showed a significant increase in the surface oxygen content. LSCM results showed that the plasma treatments greatly increased fluorescence dye concentrations on the surface and higher diffusion rate to the fiber center. The tensile strength of UHMPE fiber either remained unchanged or decreased by 10–13.6% after plasma treatment. The contact angle exhibited a characteristic increase in wettability, due to the polar groups introduced by plasma treatment. The microbond test showed that the interfacial shear strengths (IFSS) increase significantly (57–139%) after plasma treatment for all groups and the optimum activation is obtained at 100°C and 5 W power input. SEM analysis showed roughened surfaces after the plasma treatments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Structure and processability of iodinated poly(vinyl alcohol). IV. Drawability of the films iodinated at solution before casting
Authors: Shin Eun Joo , Lee Yang Hun , Choi Suk Chul
Published: December 2007

The drawability of iodinated at solution before casting (IBC) polyvinyl alcohol films prepared by casting aqueous solutions of 10 wt % PVA containing 15.2, 39.8, 83.2, 117.0, and 140.1% was examined with a tensile tester at 20–60°C. The tensile behavior of IBC films showed that the yield and breaking loads were much lower, and the breaking elongation was even higher than those of the unoriented iodinated after casting (IAC) films as well as the untreated PVA films. The maximum draw ratios of the films with the weight gain of 15.2, 39.8, 83.2, 117, and 140.1% were 4.5, 5.5, 8.5, 8.0, and 7.5, respectively, which were achieved at 20°C in all. The crystallinity of all films increased by the maximum draw, regardless of crystallinity before drawing. The crystalline structure was recovered to the original PVA crystalline lattice by deiodination. Amorphous orientation and initial moduli increased with the maximum draw ratio, while the orientation of crystals was constant. The orientation and moduli increased up to the weight gain of 83.2%, whose highest draw ratio and initial modulus were 8.5 and of 7.1 GPa, respectively, and then decreased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Preparation and characterization of a semi‐interpenetrating network gel polymer electrolyte
Authors: Li Wei‐Li , Xu Li‐Xing , Luo Dan , Yuan Ming‐Yong , Yang Mujie
Published: December 2007

Poly(PEG200 maleate) was synthesized as a new type crosslinkable prepolymer and the semi‐interpenetrating polymer network (semi‐IPN) gel electrolytes were prepared by means of thermal polymerization. Their intrinsic properties were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC), X‐ray diffractions (XRD), scanning electron microscopy, alternating current impedance (AC impedance), and linear sweep voltammetry. The prepared polymer hosts are transparent and have good mechanical properties. The results of DSC and XRD confirm that the prepared hosts are in amorphous state and they can hold enough liquid electrolytes, which is favorable for Li+ ions to transport via both the absorbed liquid electrolyte and the gel of the entire systems. The semi‐IPN gel electrolytes exhibit high ionic conductivity on the order of 10−3 S cm−1. Their electrochemical stability up to +4.6 V against Li+/Li also makes them potential candidates for application as polymer electrolytes in devices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Nanocomposite of chitosan and silver oxide and its antibacterial property
Authors: Hu Zhigang , Chan Wing Lai , Szeto Yau Shan
Published: December 2007

An aqueous emulsion of chitosan nanoparticles encapsulating silver oxide is prepared from silver nitrate and chitosan. The nanoparticles are positively charged with an average diameter of 300 nm. The dried particle has a spherical shape with a 100 nm diameter. The emulsion is applied onto cotton and delivers a durable antibacterial activity against S. aureus and E. coli, after 20 washings. The coefficient of friction of the treated fabric is similar to that of the untreated cotton fabric. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Diffusion through swelling membranes with a Robin boundary condition
Authors: Puri P. , Liu Q. , De Kee D.
Published: December 2007

A Robin boundary condition at the downstream surface of stretched membrane is used to study diffusion through swollen polymer membranes. Four dimensionless parameters are used to describe the diffusion process. These parameters are associated with the effect of swelling, relaxation, and retardation times of the polymer matrix as well as the normal derivative condition at the downstream side of the membrane. The effect of these four parameters is discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Metal ion‐imprinted polymer microspheres derived from copper methacrylate for selective separation of heavy metal ions
Authors: Dam Anh Hoang , Kim Dukjoon
Published: December 2007

Microbeads of metal ion‐imprinted polymers (MIIPs) were prepared by a novel precipitation polymerization technique, in which copper methacrylate monomer and ethylene glycol dimethacrylate crosslinker were copolymerized in a rotary evaporator. The prepared microbeads had mono‐ or narrow size dispersity, and their sizes increased from 1 to 4 μm with decreasing solvent amount or increasing initiator concentration. The absorption capacity and selectivity of the imprinted polymer for copper ion were determined in the presence of various competitive metal ions. As results, adsorption equilibrium was quickly achieved in about 10 min with high absorbability (about 90%). The effects of pH, initial metallic ion concentration, and MIIP bead size on the absorption capacity were investigated. The Cu(II)‐imprinted polymers exhibited extremely high selectivity, which was much higher than that of corresponding blank polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Improvement of conductivity of electrochemically synthesized polyaniline
Authors: Bhadra Sambhu , Chattopadhyay Santanu , Singha Nikhil K. , Khastgir Dipak
Published: December 2007

The electrochemical polymerization of aqueous solution of aniline and HCl was carried out in a single compartment electrochemical cell. After 2 h of the polymerization reaction, polarity of the electrodes was reversed and kept for 1 h. By this process the conductivity of the polyaniline (PAni) formed was found to increase dramatically from 1.1 × 10−4 to 3.0 × 10−1 S/cm. The PAni samples obtained both by reversing the polarity (“PANI‐R”) and without reversing the polarity (“PANI”) were characterized by the infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), ultraviolet spectroscopy (UV), Hall effect experiment, X‐ray analysis (XRD) and scanning electron microscope (SEM). The results show that the increase in the conductivity of PAni through the reversion of polarity is due to the partial reduction of over oxidized sample giving more emeraldine base and hence more polaron formation with increased charge carrier density and its mobility. The degree of crystallinity and the crystallite size is decreased marginally and the d‐spacing is increased marginally due to this reduction. The PAni behaves like a p‐type semiconductor that means the majority current carriers are holes. A plausible reduction mechanism due to reversal of polarity during electrochemical polymerization is also proposed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Dynamic mechanical properties of styrene‐butadiene composites reinforced by defatted soy flour and carbon black co‐filler
Authors: Jong L.
Published: December 2007

Carboxylated styrene‐butadiene (SB) composites reinforced by a mixture of defatted soy flour (DSF) and carbon black (CB) were investigated in terms of their dynamic mechanical properties. DSF is an abundant renewable commodity and has a lower cost than CB. DSF contains soy protein, carbohydrate, and whey. Aqueous dispersions of DSF and CB were first mixed and then blended with SB latex to form rubber composites using freeze‐drying and compression molding methods. At 140°C, a single filler composite reinforced by 30% DSF exhibited roughly a 230‐fold increase in the shear elastic modulus compared to the unfilled SB rubber, indicating a significant reinforcement effect by DSF. Mixtures of DSF and CB at three different ratios were investigated as co‐fillers. Temperature sweep experiments indicate the shear elastic moduli of the co‐filler composites are between that of DSF and CB composites. Strain sweep experiments were used to study the fatigue and recovery behaviors of these composites. Compared with the DSF composites, the recovery behaviors of the 30% co‐filler composites after the eight consecutive deformation cycles of dynamic strain were improved and similar to that of 30% CB composite. Strain sweep experiments also indicated that the co‐filler composites have a greater elastic modulus than the CB reinforced composites within the strain range measured. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Striped‐pattern deterioration and morphological analysis of injection molding comprising polypropylene/ethylene–α‐olefin rubber blends. II. Influence of heating
Authors: Hirano Koki , Tamura Satoshi , Obata Yutaka , Kanai Toshitaka
Published: December 2007

Unique deterioration with a striped pattern caused by thermal heating is reported for injection molding comprising polypropylene/ethylene–α‐olefin rubber blends. This stripe is due to the formation of glossy and cloudy parts in alternation approximately perpendicular to the flow direction of the molten resin. On the surface of the cloudy part, a number of micro‐objects appear. They have a dome shape about 10 μm in diameter and 2 μm height. Some experimental evidence indicates that the objects are composed of the rubber contained in the blends. On the other hand, only a few objects appear in the glossy region after heating. This is the reason that the stripe with the micro‐objects (migrating rubber to the surface) is examined in terms of a higher order structure of injection molding with laser scanning microscopy, wide‐angle X‐ray scattering, and microhardness (Martens hardness). Consequently, we have concluded that this thermally deteriorated stripe depends on periodic changes in the crystallinity along the flow direction. The evidence indicates that a snakelike flow occurs during the injection process of the molding. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Improvement of adhesion and long‐term adhesive reliability of liquid crystalline polyester film by plasma treatment
Authors: Kurihara Yasuhiro , Ohata Hiroyuki , Kawaguchi Masahiko , Yamazaki Shinichi , Kimura Kunio
Published: December 2007

Surface modification of thermotropic liquid crystalline aromatic polyester (LCP) films was examined by low‐pressure plasma treatment to improve initial adhesion and long‐term adhesive reliability between the LCP film and an epoxy bonding sheet for printed circuit boards. Plasma irradiation was carried out in various plasma gases with different plasma modes as reactive‐ion‐etching (RIE), direct‐plasma (DP) with pressures ranging from 4.0 to 26.6 Pa. Although the initial adhesion of the DP‐treated film increased, the long‐term adhesive reliability estimated by pressure cooker test (PCT) decreased with decreasing the plasma gas pressure in every gas. The higher concentration of the generated polar groups such as phenolic hydroxyl group and carboxyl group enhanced the initial adhesion by the increase in the chemical interaction; however, it damaged the long‐term adhesive reliability due to the acceleration of the penetration of water molecules into the interface. The large surface roughness was effective to enhance the initial adhesion and the long‐term adhesive reliability. The RIE‐treatment generated the polar groups and the larger surface roughness than the DP‐treatment. The RIE‐treatment in the O2 atmosphere at the gas pressure of 13.3 Pa was the best plasma condition for both the initial adhesion and the long‐term adhesive reliability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Ring‐opening copolymerization and properties of polycarbonate copolymers
Authors: Mei Li‐Li , Yan Guo‐Ping , Yu Xiang‐Hua , Cheng Si‐Xue , Wu Jiang‐Yu
Published: December 2007

A series of polycarbonate copolymers were synthesized by the ring‐opening bulk polymerization of 2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate (PTC) and 5,5‐dimethyl trimethylene carbonate (DTC) with tin(II) 2‐ethylhexanoate and aluminum isopropoxide as initiators. The copolymers obtained were characterized by 1H‐NMR, Fourier transform infrared, and ultraviolet. The influence of the molar ratio of the monomers, the initiators, and their concentrations, the reaction time, and the reaction temperature on the copolymerization was also studied. The copolymerization of monomers DTC and PTC was a nonideal copolymerization, and the copolymerization reactivity ratio of the monomer DTC was higher than that of PTC in the copolymerization process. In vitro release profiles of fluorouracil from the copolymers showed that the copolymer had a steady drug‐release rate and good controlled‐release property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Axoneme specialization embedded in a “Generalist” β‐tubulin
Authors: Popodi Ellen M. , Hoyle Henry D. , Turner F. Rudolf , Xu Ke , Kruse Spencer , Raff Elizabeth C.
Published: December 2007

The relationship between the primary structure of the β‐tubulin C‐terminal tail (CTT) and axoneme structure and function is explored using the spermatogenesis‐specific β2‐tubulin of Drosophila. We previously showed that all β‐tubulins used for motile 9 + 2 axonemes contain a conserved sequence motif in the proximal part of the CTT, the β‐tubulin axoneme motif. The differential ability of tubulin isoforms and abilities of β2‐tubulin C‐terminal truncations to form axonemes led us to hypothesize that the axoneme motif is essential for axoneme formation and the distal half of the CTT was less important. The studies we report here indicate that it is not that simple. Unexpectedly, some changes in the core sequence of the axoneme motif did not disrupt formation of motile axonemes. And, while deletion of the distal CTT did not disrupt the ability to produce functional sperm [Popodi et al., Cell Motil Cytoskeleton 2005;62:48–64], changing the amino acid sequence in this region can. Thus both regions are important. The deep conservation of the axoneme motif in all eukaryotic groups implies that the presence of the sequence motif confers a functional advantage. The central pair is the axoneme structure most sensitive to perturbations in tubulin molecules; we hypothesize central pair assembly is facilitated by the presence of this motif. Our data reveal that β2‐tubulin has robust properties for axoneme assembly, and that axonemal specializations are embedded in both the CTT and the body of the β2 molecule. Cell Motil. Cytoskeleton 2008. © 2007 Wiley‐Liss, Inc.
Building a radial spoke: Flagellar radial spoke protein 3 (RSP3) is a dimer
Authors: Wirschell Maureen , Zhao Feifei , Yang Chun , Yang Pinfen , Diener Dennis , Gaillard Anne , Rosenbaum Joel L. , Sale Winfield S.
Published: December 2007

Radial spokes are critical multisubunit structures required for normal ciliary and eukaryotic flagellar motility. Experimental evidence indicates the radial spokes are mechanochemical transducers that transmit signals from the central pair apparatus to the outer doublet microtubules for local control of dynein activity. Recently, progress has been made in identifying individual components of the radial spoke, yet little is known about how the radial spoke is assembled or how it performs in signal transduction. Here we focus on radial spoke protein 3 (RSP3), a highly conserved AKAP located at the base of the radial spoke stalk and required for radial spoke assembly on the doublet microtubules. Biochemical approaches were taken to further explore the functional role of RSP3 within the radial spoke structure and for control of motility. Chemical crosslinking, native gel electrophoresis, and epitope‐tagged RSP3 proteins established that RSP3 forms a dimer. Analysis of truncated RSP3 proteins indicates the dimerization domain coincides with the previously characterized axoneme binding domain in the N‐terminus. We propose a model in which each radial spoke structure is built on an RSP3 dimer, and indicating that each radial spoke can potentially localize multiple PKAs or AKAP‐binding proteins in position to control dynein activity and flagellar motility. Cell Motil. Cytoskeleton 2008. © 2007 Wiley‐Liss, Inc.
Local Self‐Assembly Mechanisms Underlie the Differential Transformation of the Proximal and Distal Cut Axonal Ends Into Functional and Aberrant Growth Cones
Authors: Erez Hadas , Spira Micha
Published: December 2007

Following axotomy both the proximal and distal cut axonal ends transform into growth cones. Whereas the growth cone formed by the tip of the proximal segment branch to form neurites (left hand side), the structure formed by the distal cut end fails to grow. In redmicrotubules, blue ‐ vesicles, and green ‐ actin. J. Comp. Neurol. 507:1019–1030, 2007. © 2007 Wiley‐Liss, Inc.
Organizational diversity, integration and performance
Authors: Van de Ven Andrew H. , Rogers Russel W. , Bechara John P. , Sun Kangyong
Published: December 2007

This research examines how integrative methods of open communications, involvement, and conflict resolution in implementing an organizational change initiative moderate the relationship between cognitive diversity among employees and organization performance. In this longitudinal study of 37 medical clinics, we find that the interaction of integrative methods and diversity of models for organizing among employees has a significant positive effect on clinic revenue, productivity, and patient satisfaction. An important practical implication of these findings is that instead of seeking consensus on a singular vision of a strategic change initiative, managers are more likely to improve organization performance by focusing their interventions on creating integrative methods for encouraging and learning from diverse and opposing views of an organizational change initiative. Copyright © 2007 John Wiley & Sons, Ltd.
Factors of values in the Dutch Language and their relationship to factors of personality
Authors: De Raad Boele , Van Oudenhoven Jan Pieter
Published: December 2007

Following the psycholexical approach, several thousands of potential value descriptors were selected from the Dutch lexicon. This set was subsequently reduced according to criteria of relevance to a list of 641 values. The value list was administered to 634 participants (self‐ and other‐raters), who had to indicate the extent to which each value was a guiding principle in the life of the target. Principal component analyses were performed yielding eight factors of values. In addition, ratings were collected on markers of three other systems of values, including the one described by Schwartz (1992). Finally, A Big Five questionnaire, the FFPI, was administered. Correlation and regression analyses were performed to describe the relations between the different value systems, and between the Dutch value system and the Big Five factors. Copyright © 2007 John Wiley & Sons, Ltd.
Retinoid metabolism and nuclear receptor responses: New insights into coordinated regulation of the PPAR–RXR complex
Authors: Ziouzenkova Ouliana , Plutzky Jorge
Published: December 2007

Retinoids, naturally‐occurring vitamin A derivatives, regulate metabolism by activating specific nuclear receptors, including the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). RXR, an obligate heterodimeric partner for other nuclear receptors, including peroxisome proliferator‐activated receptors (PPARs), helps coordinate energy balance. Recently, many groups have identified new connections between retinoid metabolism and PPAR responses. We found that retinaldehyde (Rald), a molecule that can yield RA through the action of retinaldehyde dehydrogenases (Raldh), is present in fat in vivo and can inhibit PPARγ‐induced adipogenesis. In vitro, Rald inhibits RXR and PPARγ activation. Raldh1‐deficient mice have increased Rald levels in fat, higher metabolic rates and body temperatures, and are protected against diet‐induced obesity and insulin resistance. Interestingly, one specific asymmetric β‐carotene cleavage product, apo‐14′‐carotenal, can also inhibit PPARγ and PPARα responses. These data highlight how pathways of β‐carotene metabolism and specific retinoid metabolites may have direct distinct metabolic effects.
Mammalian acyl-CoA:lysophosphatidylcholine acyltransferase enzymes
Authors: Soupene Eric , Fyrst Henrik , Kuypers Frans A.
Published: December 2007

The mammalian RBC lacks
de novo
lipid synthesis but maintains its membrane composition by rapid turnover of acyl moieties at the
sn
-2 position of phospholipids. Plasma-derived fatty acids are esterified to acyl-CoA by acyl-CoA synthetases and transferred to lysophospholipids by acyl-CoA:lysophospholipid acyltransferases. We report the characterization of three lysophosphatidylcholine (lysoPC) acyltransferases (LPCATs), products of the
AYTL1
, -
2
, and -
3
genes. These proteins are three members of a LPCAT family, of which all three genes are expressed in an erythroleukemic cell line.
Aytl2
mRNA was detected in mouse reticulocytes, and the presence of the product of the human ortholog was confirmed in adult human RBCs. The three murine Aytl proteins generated phosphatidylcholine from long-chain acyl-CoA and lysoPC when expressed in
Escherichia coli
membranes. Spliced variants of
Aytl1
, affecting a conserved catalytic motif, were identified. Calcium and magnesium modulated LPCAT activity of both Aytl1 and -2 proteins that exhibit EF-hand motifs at the C terminus. Characterization of the product of the
Aytl2
gene as the phosphatidylcholine reacylating enzyme in RBCs represents the identification of a plasma membrane lysophospholipid acyltransferase and establishes the function of a LPCAT protein.
Amplified temperature dependence in ecosystems developing on the lava flows of Mauna Loa, Hawai'i
Authors: Anderson-Teixeira Kristina J. , Vitousek Peter M. , Brown James H.
Published: December 2007

Through its effect on individual metabolism, temperature drives biologically controlled fluxes and transformations of energy and materials in ecological systems. Because primary succession involves feedbacks among multiple biological and abiotic processes, we expected it to exhibit complex dynamics and unusual temperature dependence. We present a model based on first principles of chemical kinetics to explain how biologically mediated temperature dependence of “reactant” concentrations can inflate the effective temperature dependence of such processes. We then apply this model to test the hypothesis that the temperature dependence of early primary succession is amplified due to more rapid accumulation of reactants at higher temperatures. Using previously published data from the lava flows of Mauna Loa, HI, we show that rates of vegetation and soil accumulation as well as rates of community compositional change all display amplified temperature dependence (Q
10
values of ≈7–50, compared with typical Q
10
values of 1.5–3 for the constituent biological processes). Additionally, in young ecosystems, resource concentrations increase with temperature, resulting in inflated temperature responses of biogeochemical fluxes. Mauna Loa's developing ecosystems exemplify how temperature-driven, biologically mediated gradients in resource availability can alter the effective temperature dependence of ecological processes. This mechanistic theory should contribute to understanding the complex effects of temperature on the structure and dynamics of ecological systems in a world where regional and global temperatures are changing rapidly.
Salicylic Acid and Systemic Acquired Resistance Play a Role in Attenuating Crown Gall Disease Caused byAgrobacterium tumefaciens
Authors: Anand Ajith , Uppalapati Srinivasa Rao , Ryu Choong-Min , Allen Stacy N. , Kang Li , Tang Yuhong , Mysore Kirankumar S.
Published: December 2007

We investigated the effects of salicylic acid (SA) and systemic acquired resistance (SAR) on crown gall disease caused by Agrobacterium tumefaciens. Nicotiana benthamiana plants treated with SA showed decreased susceptibility to Agrobacterium infection. Exogenous application of SA to Agrobacterium cultures decreased its growth, virulence, and attachment to plant cells. Using Agrobacterium whole-genome microarrays, we characterized the direct effects of SA on bacterial gene expression and showed that SA inhibits induction of virulence (vir) genes and the repABC operon, and differentially regulates the expression of many other sets of genes. Using virus-induced gene silencing, we further demonstrate that plant genes involved in SA biosynthesis and signaling are important determinants for Agrobacterium infectivity on plants. Silencing of ICS (isochorismate synthase), NPR1 (nonexpresser of pathogenesis-related gene 1), and SABP2 (SA-binding protein 2) in N. benthamiana enhanced Agrobacterium infection. Moreover, plants treated with benzo-(1,2,3)-thiadiazole-7-carbothioic acid, a potent inducer of SAR, showed reduced disease symptoms. Our data suggest that SA and SAR both play a major role in retarding Agrobacterium infectivity.
Evolutionary Radiation Pattern of Novel Protein Phosphatases Revealed by Analysis of Protein Data from the Completely Sequenced Genomes of Humans, Green Algae, and Higher Plants
Authors: Kerk David , Templeton George , Moorhead Greg B.G.
Published: December 2007

In addition to the major serine/threonine-specific phosphoprotein phosphatase, Mg2+-dependent phosphoprotein phosphatase, and protein tyrosine phosphatase families, there are novel protein phosphatases, including enzymes with aspartic acid-based catalysis and subfamilies of protein tyrosine phosphatases, whose evolutionary history and representation in plants is poorly characterized. We have searched the protein data sets encoded by the well-finished nuclear genomes of the higher plants Arabidopsis (Arabidopsis thaliana) and Oryza sativa, and the latest draft data sets from the tree Populus trichocarpa and the green algae Chlamydomonas reinhardtii and Ostreococcus tauri, for homologs to several classes of novel protein phosphatases. The Arabidopsis proteins, in combination with previously published data, provide a complete inventory of known types of protein phosphatases in this organism. Phylogenetic analysis of these proteins reveals a pattern of evolution where a diverse set of protein phosphatases was present early in the history of eukaryotes, and the division of plant and animal evolution resulted in two distinct sets of protein phosphatases. The green algae occupy an intermediate position, and show similarity to both plants and animals, depending on the protein. Of specific interest are the lack of cell division cycle (CDC) phosphatases CDC25 and CDC14, and the seeming adaptation of CDC14 as a protein interaction domain in higher plants. In addition, there is a dramatic increase in proteins containing RNA polymerase C-terminal domain phosphatase-like catalytic domains in the higher plants. Expression analysis of Arabidopsis phosphatase genes differentially amplified in plants (specifically the C-terminal domain phosphatase-like phosphatases) shows patterns of tissue-specific expression with a statistically significant number of correlated genes encoding putative signal transduction proteins.
Dual Targeting of Arabidopsis HOLOCARBOXYLASE SYNTHETASE1: A Small Upstream Open Reading Frame Regulates Translation Initiation and Protein Targeting
Authors: Puyaubert Juliette , Denis Laurence , Alban Claude
Published: December 2007

Protein biotinylation is an original and very specific posttranslational modification, compartmented in plants, between mitochondria, plastids, and the cytosol. This reaction modifies and activates few carboxylases committed in key metabolisms and is catalyzed by holocarboxylase synthetase (HCS). The molecular bases of this complex compartmentalization and the relative function of each of the HCS genes, HCS1 and HCS2, identified in Arabidopsis (Arabidopsis thaliana) are mainly unknown. Here, we showed by reverse genetics that the HCS1 gene is essential for plant viability, whereas disruption of the HCS2 gene in Arabidopsis does not lead to any obvious phenotype when plants are grown under standard conditions. These findings strongly suggest that HCS1 is the only protein responsible for HCS activity in Arabidopsis cells, including the cytosolic, mitochondrial, and plastidial compartments. A closer study of HCS1 gene expression enabled us to propose an original mechanism to account for this multiplicity of localizations. Located in the HCS1 messenger RNA 5′-untranslated region, an upstream open reading frame regulates the translation initiation of HCS1 and the subsequent targeting of HCS1 protein. Moreover, an exquisitely precise alternative splicing of HCS1 messenger RNA can regulate the presence and absence of this upstream open reading frame. The existence of these complex and interdependent mechanisms creates a rich molecular platform where different parameters and factors could control HCS targeting and hence biotin metabolism.
Arabidopsis GenesAS1,AS2, andJAGNegatively Regulate Boundary-Specifying Genes to Promote Sepal and Petal Development
Authors: Xu Ben , Li Ziyu , Zhu Yan , Wang Hua , Ma Hong , Dong Aiwu , Huang Hai
Published: December 2007

Boundary formation is crucial for organ development in multicellular eukaryotes. In higher plants, boundaries that separate the organ primordia from their surroundings have relatively low rates of cell proliferation. This cellular feature is regulated by the actions of certain boundary-specifying genes, whose ectopic expression in organs can cause inhibition of organ growth. Here, we show that the Arabidopsis thaliana ASYMMETRIC LEAVES1 and 2 (AS1 and AS2) and JAGGED (JAG) genes function in the sepal and petal primordia to repress boundary-specifying genes for normal development of the organs. Loss-of-function as1 jag and as2 jag double mutants produced extremely tiny sepals and petals. Analysis of a cell-cycle marker HISTONE4 revealed that cell division in sepal primordia of the double mutant was inhibited. Moreover, these abnormal sepals and petals exhibited ectopic overexpression of the boundary-specifying genes PETAL LOSS (PTL) and CUP-SHAPED COTYLEDONS1 and 2 (CUC1 and CUC2). Loss of PTL or CUC1 and CUC2 functions in the as1 jag background could partially rescue the tiny sepal and petal phenotypes, supporting the model that the tiny sepal/petal phenotypes are caused, at least in part, by ectopic expression of boundary-specifying genes. Together, our data reveal a previously unrecognized fundamental regulation by which AS1, AS2, and JAG act to define sepal and petal from their boundaries.
Systemic and Intracellular Responses to Photooxidative Stress inArabidopsis
Authors: Rossel Jan Bart , Wilson Pip B. , Hussain Dawar , Woo Nick S. , Gordon Matthew J. , Mewett Osman P. , Howell Katharine A. , Whelan Jim , Kazan Kemal , Pogson Barry J.
Published: December 2007

As the sun tracks daily through the sky from east to west, different parts of the canopy are exposed to high light (HL). The extent of and mechanisms by which a systemic acquired acclimation (SAA) response might preacclimate shaded leaves that will be subsequently exposed to full sunlight is largely undefined. We investigated the role of an Arabidopsis thaliana zinc finger transcription factor, ZAT10, in SAA. ZAT10 overexpression resulted in enhanced tolerance to photoinhibitory light and exogenous H2O2, increased expression of antioxidative genes whose products are targeted to multiple subcellular compartments. Partial HL exposure of a leaf or leaves rapidly induced ZAT10 mRNA in distal, shaded photosynthetic tissues, including the floral stem, cauline leaves, and rosette, but not in roots. Fully 86% of fivefold HL-upregulated and 71% of HL-downregulated genes were induced and repressed, respectively, in distal, shaded leaves. Between 15 and 23% of genes whose expression changed in the HL and/or distal tissues were coexpressed in the ZAT10 overexpression plants, implicating ZAT10 in modulating the expression of SAA-regulated genes. The SAA response was detectable in plants with mutations in abscisic acid, methyl jasmonate, or salicylic acid synthesis or perception, and systemic H2O2 diffusion was not detected. Hence, SAA is distinct from pathogen-stimulated systemic acquired resistance and apparently involves a novel signal or combination of signals that preacclimate photosynthetic tissues to HL.
An Endoplasmic Reticulum Stress Response in Arabidopsis Is Mediated by Proteolytic Processing and Nuclear Relocation of a Membrane-Associated Transcription Factor, bZIP28
Authors: Liu Jian-Xiang , Srivastava Renu , Che Ping , Howell Stephen H.
Published: December 2007

Stresses leading to the accumulation of misfolded proteins in the endoplasmic reticulum (ER) elicit a highly conserved ER stress response in plants called the unfolded protein response (UPR). While the response itself is well documented in plants, the components of the signaling pathway are less well known. We have identified three membrane-associated basic domain/leucine zipper (bZIP) factors in Arabidopsis thaliana that are candidates for ER stress sensors/transducers. One of these factors, bZIP28, an ER-resident transcription factor, is activated in response to treatment by tunicamycin (TM), an agent that blocks N-linked protein glycosylation. Following TM treatment, bZIP28 is processed, releasing its N-terminal, cytoplasm-facing domain, which is translocated to the nucleus. Expression of a truncated form of bZIP28, containing only the cytoplasmic domain of the protein, upregulated the expression of ER stress response genes in the absence of stress conditions. Thus, bZIP28 serves as a sensor/transducer in Arabidopsis to mediate ER stress responses related to UPR.
P-Glycoprotein4 Displays Auxin Efflux Transporter–Like Action in Arabidopsis Root Hair Cells and Tobacco Cells
Authors: Cho Misuk , Lee Sang Ho , Cho Hyung-Taeg
Published: December 2007

ATP binding cassette (ABC) transporters transport diverse substrates across membranes in various organisms. However, plant ABC transporters have only been scantily characterized. By taking advantage of the auxin-sensitive Arabidopsis thaliana root hair cell and tobacco (Nicotiana tabacum) suspension cell systems, we show here that Arabidopsis P-glycoprotein4 (PGP4) displays auxin efflux activity in plant cells. Root hair cell–specific overexpression of PGP4 (PGP4ox) and known auxin efflux transporters, such as PGP1, PGP19, and PIN-FORMEDs, decreased root hair elongation, whereas overexpression of the influx transporter AUXIN-RESISTANT1 enhanced root hair length. PGP4ox-mediated root hair shortening was rescued by the application of auxin or an auxin efflux inhibitor. These results indicate that the increased auxin efflux activity conferred by PGP4 reduces auxin levels in the root hair cell and consequently inhibits root hair elongation. PGP4ox in tobacco suspension cells also increased auxin efflux. PGP4 proteins were targeted to the plasma membrane of Arabidopsis root hair cells and tobacco cells without any clear subcellular polarity. Brefeldin A partially interfered with the trafficking of PGP4 reversibly, and this was rescued by pretreatment with auxin. These results suggest that PGP4 is an auxin efflux transporter in plants and that its trafficking to the plasma membrane involves both BFA-sensitive and -insensitive pathways.
RAR1 and HSP90 Form a Complex with Rac/Rop GTPase and Function in Innate-Immune Responses in Rice
Authors: Thao Nguyen Phuong , Chen Letian , Nakashima Ayako , Hara Shin-ichiro , Umemura Kenji , Takahashi Akira , Shirasu Ken , Kawasaki Tsutomu , Shimamoto Ko
Published: December 2007

A rice (Oryza sativa) Rac/Rop GTPase, Os Rac1, is involved in innate immunity, but its molecular function is largely unknown. RAR1 (for required for Mla12 resistance) and HSP90 (a heat shock protein 90 kD) are important components of R gene–mediated disease resistance, and their function is conserved in several plant species. HSP90 has also recently been shown to be important in mammalian innate immunity. However, their functions at the molecular level are not well understood. In this study, we examined the functional relationships between Os Rac1, RAR1, and HSP90. Os RAR1-RNA interference (RNAi) rice plants had impaired basal resistance to a compatible race of the blast fungus Magnaporthe grisea and the virulent bacterial blight pathogen Xanthomonas oryzae. Constitutively active Os Rac1 complemented the loss of resistance, suggesting that Os Rac1 and RAR1 are functionally linked. Coimmunoprecipitation experiments with rice cell culture extracts indicate that Rac1 forms a complex with RAR1, HSP90, and HSP70 in vivo. Studies with Os RAR1-RNAi and treatment with geldanamycin, an HSP90-specific inhibitor, showed that RAR1 and HSP90 are essential for the Rac1-mediated enhancement of pathogen-associated molecular pattern–triggered immune responses in rice cell cultures. Furthermore, the function of HSP90, but not RAR1, may be essential for their association with the Rac1 complex. Os Rac1 also regulates RAR1 expression at both the mRNA and protein levels. Together, our results indicate that Rac1, RAR1, HSP90, and HSP70 form one or more protein complexes in rice cells and suggest that these proteins play important roles in innate immunity in rice.
Regulation of Rice NADPH Oxidase by Binding of Rac GTPase to Its N-Terminal Extension
Authors: Wong Hann Ling , Pinontoan Reinhard , Hayashi Kokoro , Tabata Ryo , Yaeno Takashi , Hasegawa Kana , Kojima Chojiro , Yoshioka Hirofumi , Iba Koh , Kawasaki Tsutomu , Shimamoto Ko
Published: December 2007

Reactive oxygen species (ROS) produced by NADPH oxidase play critical roles in various cellular activities, including plant innate immunity response. In contrast with the large multiprotein NADPH oxidase complex of phagocytes, in plants, only the homologs of the catalytic subunit gp91phox and the cytosolic regulator small GTPase Rac are found. Plant homologs of the gp91phox subunit are known as Rboh (for respiratory burst oxidase homolog). Although numerous Rboh have been isolated in plants, the regulation of enzymatic activity remains unknown. All rboh genes identified to date possess a conserved N-terminal extension that contains two Ca2+ binding EF-hand motifs. Previously, we ascertained that a small GTPase Rac (Os Rac1) enhanced pathogen-associated molecular pattern–induced ROS production and resistance to pathogens in rice (Oryza sativa). In this study, using yeast two-hybrid assay, we found that interaction between Rac GTPases and the N-terminal extension is ubiquitous and that a substantial part of the N-terminal region of Rboh, including the two EF-hand motifs, is required for the interaction. The direct Rac–Rboh interaction was supported by further studies using in vitro pull-down assay, a nuclear magnetic resonance titration experiment, and in vivo fluorescence resonance energy transfer (FRET) microscopy. The FRET analysis also suggests that cytosolic Ca2+ concentration may regulate Rac–Rboh interaction in a dynamic manner. Furthermore, transient coexpression of Os Rac1 and rbohB enhanced ROS production in Nicotiana benthamiana, suggesting that direct Rac–Rboh interaction may activate NADPH oxidase activity in plants. Taken together, the results suggest that cytosolic Ca2+ concentration may modulate NADPH oxidase activity by regulating the interaction between Rac GTPase and Rboh.
Pronophiline butterflies (Satyridae) of the Serrania de Valledupar, Colombia–Venezuela border
Authors: ADAMS M. J. , BERNARD G. I.
Published: January 2008

Abstract. The thirty‐one species of the tribe Pronophilini found by the authors in the little‐known mountain range on the northern borders of Colombia and Venezuela, the Serrania de Valledupar, are listed. Their recorded altitude limits are given, as well as notes on their habits and behaviour. The existence, among twenty of the species, of series of two or three closely related congeners replacing one another up the altitude gradient, is commented upon. Two cases of mimicry between species from different genera are reported. One new genus, fourteen new species and one new subspecies are described. Two new synonymies are established, the status of one taxon revised, and new status given to another.
A revision of the tribe Plectrothripini of fungus‐feeding Thysanoptera (Phlaeothripidae: Phlaeothripinae)
Authors: OKAJIMA SHÛJI
Published: January 2008

Abstract The tribe Plectrothripini is redefined with examination of its systematic relationships. Keys are provided to the ten genera and forty‐seven species in this tribe; one genus and eighteen species are newly described; one genus and two species are newly synonymized; two genera, Chiridothrips and Eurytrichothrips, are here removed from this tribe. The species of the tribe occur throughout the tropical and subtropical regions of the world; seventeen species are recorded from the Oriental Region, seventeen species from the Neotropical Region, ten species from the Afrotropical Region, two from Australia and one from the Pacific. They seem to be fungus‐feeders, being found mainly under the bark of trees or on dead branches.