bluuebunny/crossref_metadata_2025 huggingface dataset:
Update and challenges on proteomics in rice
Authors: Komatsu Setsuko , Yano Hiroyuki
Published: June 2006

Rice is not only an important agricultural resource but also a model plant for biological research. Our previous review highlighted different aspects of the construction of rice proteome database, cataloguing rice proteins of different tissues and organelle, differential proteomics using 2‐DE and functional characterization of some of the proteins identified (Komatsu, S., Tanaka, N., Proteomics 2005, 5, 938–949). In this review, the powerfulness and weaknesses of proteomic technologies as a whole and limitations of the currently used techniques in rice proteomics are discussed. The information obtained from these techniques regarding proteins modification, protein‐protein interaction and the development of new methods for differential proteomics will aid in deciphering more precisely the functions of known and/or unknown proteins in rice.
Analytical method for assessing potential dermal exposure to captan, using whole body dosimetry, in small vegetable production units in Argentina
Authors: Hughes Enrique A , Zalts Anita , Ojeda Javier J , Flores Andrea P , Glass Richard C , Montserrat Javier M
Published: June 2006

An analytical method has been developed that can be used to determine the potential dermal exposure (PDE) of workers to the pesticide captan in small‐scale horticultural production units. The methodology is based on the whole body dosimetry technique, using a cotton coverall and cotton gloves as sampling media, with protective clothing worn beneath the cotton media to protect the operator. The quantitative determination of captan was done by gas chromatography‐electron capture detector (GC‐ECD), with the analytical method validated by measuring limits of detection and quantification, linear ranges, sample recovery and precision. Special emphasis is placed on factors that affected the stability of captan during chromatographic determination. The data generated for potential dermal exposure are presented separately for mixing/loading and application activities. These data are compared with values obtained with visible tracers using a similar field technique. Margin of safety (MOS) values are also calculated for the agricultural procedures studied. Copyright © 2006 Society of Chemical Industry
Hazards and uptake of chitin synthesis inhibitors in bumblebees Bombus terrestris
Authors: Mommaerts Veerle , Sterk Guido , Smagghe Guy
Published: June 2006

This research project examined the potential hazards of a major class of insect growth regulators (IGRs) to survival, reproduction and larval growth in bumblebees Bombus terrestris L. Eight chitin synthesis inhibitors (CSIs) were tested: buprofezin, cyromazine, diflubenzuron, flucycloxuron, flufenoxuron, lufenuron, novaluron and teflubenzuron. These different IGRs, which are important in the control of pest insects in greenhouses, were applied via three different routes of exposure under laboratory conditions: dermal contact, and orally via the drinking of sugar/water and via pollen. The compounds were tested at their respective maximum field recommended concentrations (MFRC) and also in dose‐response assays to calculate LC50 values. In general, none of the CSIs showed acute worker toxicity. However, there was a dramatic reduction in brood production, especially after oral treatment with pollen and sugar/water. Conspicuously, egg fertility was reduced in all treatments with diflubenzuron and teflubenzuron. In addition to egg mortality, the worker bumblebees removed larvae from the treated nest, and in most cases these individuals were dead first‐second instars. Under a binocular microscope, such larvae showed an abnormally formed cuticle leading to mechanical weakness and death. In another series of experiments using 14C‐diflubenzuron and 14C‐flufenoxuron, cuticular penetration in workers was studied for a better understanding of the differences in toxicity. With 14C‐diflubenzuron, transovarial transport and accumulation in the deposited eggs supported the strong reproductive effects. Overall, the present results suggest that CSIs should be applied with caution in combination with bumblebees. The compatibility of each compound to be used in combination with B. terrestris is discussed in relation to calculated LC50 values, routes of uptake and effects. Copyright © 2006 Society of Chemical Industry
Seed and seedling characteristics of the Himalayan hornbeam (Carpinus viminea Wall.), India
Authors: Bhatt Jitendra , Ram Jeet
Published: June 2006

To study of seed and seedling characteristics, seeds of the Himalayan Hornbeam (Carpinus viminea Wall.) were collected from low and high‐elevation sites during the peak maturation period. Paired t‐tests indicated that seed weight, percentage of sound seeds, and germination were significantly greater for high‐elevation seeds whereas seed moisture (%) was low. Seedling growth performance was better for high‐elevation seeds than for those from low elevation. This indicates that environmental conditions at high elevation may favour germination and seedling growth of the species.
Dominant negative effects of a Gβ mutant on G‐protein coupled inward rectifier K+ channel
Authors: Zhao Qi , Albsoul-Younes Abla M. , Zhao Peng , Kozasa Tohru , Nakajima Yasuko , Nakajima Shigehiro
Published: June 2006

HEK293 cells were transfected with cDNAs for Gβ1(W332A) [a mutant Gβ1], Gγ2, and inward rectifier K+ channels (Kir3.1/Kir3.2). Application of Gβ1γ2 protein to these cells activated the K+ channels only slightly. When mu‐opioid receptors and Kir3.1/Kir3.2 were transfected, application of a mu‐opioid agonist induced a Kir3 current. However, co‐expression of Gβ1(W332A) suppressed this current. Most likely, Gβ1(W332A) inhibited the action of the endogenous Gβ. Such a dominant negative effect of Gβ1(W332A) was also observed in neuronal Kir3 channels in locus coeruleus. The mutant, Gβ1(W332A) protein, although inactive, retains its ability to bind Kir3 and prevents the wild type Gβ from activating the channel.
A recurring question answered with a degree of optimism
Authors: Echenique Marcial , Short Alan , Steemers Koen
Published: June 2006

What is architectural research? That was the title of a University of Cambridge Department of Architecture symposium held at the Royal Institute of British Architects in London in September 2005. The idea of the symposium emerged during a battle to save Cambridge's Department of Architecture from closure in 2004. The University authorities had recommended closure because the Department's research rating in the UK's Research Assessment Exercise (RAE) of 2001 had dropped from 5 to 4 with a corresponding fall in research funding from the government. For a research-based university like Cambridge (where only three departments out of over 50 in the whole University scored below 5) research funding subsidises teaching so, for the University authorities, closure would have saved money and reduced its financial deficit. An outcry from within and outside the University saved the Cambridge Department, but important questions remain.
Astroglial heterogeneity closely reflects the neuronal-defined anatomy of the adult murine CNS
Authors: EMSLEY JASON G. , MACKLIS JEFFREY D.
Published: June 2006

Astroglia comprise an extremely morphologically diverse cell type that have crucial roles in neural development and function. Nonetheless, distinct regions of the CNS have traditionally been defined by the phenotypic characteristics and connectivity of neurons. In a complementary fashion, we present evidence that discrete regions of the adult CNS can be delineated based solely on the morphology, density and proliferation rates of astroglia.We used transgenic hGFAP-GFP mice in which robust expression of GFP in adult astroglia enables detailed morphological characterization of this diversely heterogeneous cell population with 3D confocal microscopy. By using three complementary methods for labeling adult astroglia (hGFAP-GFP expression, and GFAP and S100β immunostaining), we find that there is a remarkably diverse, regionally stereotypical array of astroglial morphology throughout the CNS, and that discrete anatomical regions can be defined solely on the morphology of astroglia within that region. Second, we find that the density of astroglia varies dramatically across the CNS, and that astroglial density effectively delineates even the sub-regions of complex structures, such as the thalamus. We also find that regional astroglial density varies depending on how astroglia are labeled. To quantify and illustrate these broad differences in astroglial density, we generated an anatomical density atlas of the CNS. Third, the proliferation rate, or mitotic index, of astroglia in the adult CNS also effectively defines anatomical regions. These differences are present regardless of the astroglial-labeling method used. To supplement our atlas of astroglial density we generated an atlas of proliferation density for the adult CNS. Together, these studies demonstrate that the morphology, density and proliferation rate of astroglia can independently define the discrete cytoarchitecture of the adult mammalian CNS, and support the concept that regional astroglial heterogeneity reflects important molecular and functional differences between distinct classes of astroglia, much like the long-accepted heterogeneity of neuronal populations.
Efficiency of the benthic filter: Biological control of the emission of dissolved methane from sediments containing shallow gas hydrates at Hydrate Ridge
Authors: Sommer S. , Pfannkuche O. , Linke P. , Luff R. , Greinert J. , Drews M. , Gubsch S. , Pieper M. , Poser M. , Viergutz T.
Published: June 2006

In marine sedimentary environments, microbial methanotrophy represents an important sink for methane before it leaves the seafloor and enters the water column. Using benthic observatories in conjunction with numerical modeling of pore water gradients, we investigated seabed methane emission rates at cold seep sites with underlying gas hydrates at Hydrate Ridge, Cascadia margin. Measurements were conducted at three characteristic sites which have variable fluid flow and sulfide flux and sustain distinct chemosynthetic communities. In sediments covered with microbial mats of Beggiatoa, seabed methane efflux ranges from 1.9 to 11.5 mmol m−2 d−1. At these sites of relatively high advective flow, total oxygen uptake was very fast, yielding rates of up to 53.4 mmol m−2 d−1. In sediments populated by colonies with clams of the genus Calyptogena and characterized by low advective flow, seabed methane emission was 0.6 mmol m−2 d−1, whereas average total oxygen uptake amounted to only 3.7 mmol m−2 d−1. The efficiency of methane consumption at microbial mat and clam field sites was 66 and 83%, respectively. Our measurements indicate a high potential capacity of aerobic methane oxidation in the benthic boundary layer. This layer potentially restrains seabed methane emission when anaerobic methane oxidation in the sediment becomes saturated or when methane is bypassing the sediment matrix along fractures and channels.
Numerical simulations of frictional melting: Small dependence of shear stress drop on viscosity parameters
Authors: Sirono S. , Satomi K. , Watanabe S.
Published: June 2006

Frictional melting during coseismic slipping strongly affects dynamic sliding. An idealized numerical simulation of shear stress drop due to lubrication of fault surfaces by frictional melting is performed to investigate dynamical adjustment of melt thickness and its dependence on material properties. We numerically solved one‐dimensional heat conduction equations coupled with hydrodynamic equations of motion of the melt layer. We adopt a simple Arrhenius‐type temperature dependence of melt viscosity with a parametric factor η0. After the initial transient stage, the evolution of the melt layer asymptotes to the late stage, where the melt thickness increases as and the generated shear stress drops as 1/. An analytic self‐similar solution of the temperature profile for the late stage is obtained. The balance between the viscous heat generation and conductive heat loss characterizes the late stage. For small η0, the melt thickness is proportional to η0, whereas it will saturate for a larger η0. This is because the strong temperature dependence of viscosity enables an automatic adjustment of viscosity, which drops through the temperature increase due to the viscous heating even if a large η0 is chosen. Numerical results and the thickness data of natural pseudotachylyte layers were compared. A maximum ratio X/ (X is thickness, D is sliding distance) exists above which no solution is found. The effective thermal conductivity of the melt layer should be large, probably due to the sliding surface roughness. Comparison with laboratory experimental results showed that the normal stress applied to the sample is an important parameter for stress drop.
Ecohydrology of water‐limited environments: A scientific vision
Authors: Newman Brent D. , Wilcox Bradford P. , Archer Steven R. , Breshears David D. , Dahm Clifford N. , Duffy Christopher J. , McDowell Nate G. , Phillips Fred M. , Scanlon Bridget R. , Vivoni Enrique R.
Published: June 2006

Water‐limited environments occupy about half of the Earth's land surface and contain some of the fastest growing population centers in the world. Scarcity or variable distributions of water and nutrients make these environments highly sensitive to change. Given the importance of water‐limited environments and the impacts of increasing demands on water supplies and other natural resources, this paper highlights important societal problems and scientific challenges germane to these environments and presents a vision on how to accelerate progress. We argue that improvements in our fundamental understanding of the links between hydrological, biogeochemical, and ecological processes are needed, and the way to accomplish this is by fostering integrated, interdisciplinary approaches to problem solving and hypothesis testing through place‐based science. Such an ecohydrological approach will create opportunities to develop new methodologies and ways of thinking about these complex environmental systems and help us improve forecasts of environmental change.
Pharmacological properties of Chinese hamster ovary cells coexpressing two vasoactive intestinal peptide receptors (hVPAC1 and hVPAC2)
Authors: Langer Ingrid , Gaspard Nathalie , Robberecht Patrick
Published: June 2006

In the light of recent findings that VPAC1 and VPAC2 receptors form homodimers and heterodimers, we have evaluated the function of these receptors coexpressed in the same cells, using whole‐cell and membrane preparations. Cells expressing each receptor alone were used for comparison.

The study was performed on Chinese hamster ovary cells stably transfected with both human recombinant receptors and we compared receptor occupancy and adenylate cyclase activation by VIP, Ro 25‐1553 – a VPAC2 selective agonist – and [K15,R16,L27]VIP(1‐7)/GRF(8‐27) – a VPAC1 selective agonist – on membranes prepared from each cell line and on a mixture of membranes from cells expressing each receptor individually. We also studied receptor internalization induced by the three agonists on intact cells expressing both receptors alone or together by fluorescence‐activated cell sorting using monoclonal antibodies and demonstrated by using co‐immunoprecipitation that the two receptors did interact.

The results indicated that coexpression of the receptors did not modify the recognition of ligands, nor the capacity of the agonists to stimulate adenylate cyclase activity and, in intact cells, to induce internalization of the receptors.

As a consequence, the properties of the selective ligands that were established on cell lines expressing a single population of VIP receptors were valid on cells expressing both receptors. Furthermore, the recently demonstrated VPAC1/VPAC2 receptor heterodimerization did not affect the function of either receptor.

British Journal of Pharmacology(2006)148, 1051–1059. doi:10.1038/sj.bjp.0706816
Integrated simulations of saturated neoclassical tearing modes in DIII-D, Joint European Torus, and ITER plasmas
Authors: Halpern Federico D. , Bateman Glenn , Kritz Arnold H.
Published: June 2006

A revised version of the ISLAND module [C. N. Nguyen et al., Phys. Plasmas 11, 3604 (2004)] is used in the BALDUR code [C. E. Singer et al., Comput. Phys. Commun. 49, 275 (1988)] to carry out integrated modeling simulations of DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)], Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)], and ITER [R. Aymar et al., Plasma Phys. Control. Fusion 44, 519 (2002)] tokamak discharges in order to investigate the adverse effects of multiple saturated magnetic islands driven by neoclassical tearing modes (NTMs). Simulations are carried out with a predictive model for the temperature and density pedestal at the edge of the high confinement mode (H-mode) plasma and with core transport described using the Multi-Mode model. The ISLAND module, which is used to compute magnetic island widths, includes the effects of an arbitrary aspect ratio and plasma cross sectional shape, the effect of the neoclassical bootstrap current, and the effect of the distortion in the shape of each magnetic island caused by the radial variation of the perturbed magnetic field. Radial transport is enhanced across the width of each magnetic island within the BALDUR integrated modeling simulations in order to produce a self-consistent local flattening of the plasma profiles. It is found that the main consequence of the NTM magnetic islands is a decrease in the central plasma temperature and total energy. For the DIII-D and JET discharges, it is found that inclusion of the NTMs typically results in a decrease in total energy of the order of 15%. In simulations of ITER, it is found that the saturated magnetic island widths normalized by the plasma minor radius, for the lowest order individual tearing modes, are approximately 24% for the 2∕1 mode and 12% for the 3∕2 mode. As a result, the ratio of ITER fusion power to heating power (fusion Q) is reduced from Q=10.6 in simulations with no NTM islands to Q=2.6 in simulations with fully saturated NTM islands.
Clebsch-Gordan coefficients for U(8)⊃O(8)⊃SU(3)
Authors: Sánchez Lima I. , Hess P. O.
Published: June 2006

The group chain U(8)⊃O(8)⊃SU(3) plays an important role in many particle systems whenever the fundamental particles have eight degrees of freedom. As a particular example, the systems of many gluons and pairs of quark-antiquark are discussed, which can be coupled to a flavor octet. In order to determine the explicit structure of states and decay probabilities, the calculation of the Clebsch-Gordan coefficients (CGC) of this group chain is indispensable. In this contribution, the polynomial states of the U(8) chain are constructed and also the isoscalar factors of the CGC’s. Tables of isoscalar factors are presented. The method shown serves as an example for higher rank groups.
Raman scattering and high temperature ferromagnetism of Mn-doped ZnO nanoparticles
Authors: Wang J. B. , Huang G. J. , Zhong X. L. , Sun L. Z. , Zhou Y. C. , Liu E. H.
Published: June 2006

Raman scattering has been used to study the influence of manganese, an effective dopant to obtain ZnO diluted magnetic semiconductors, on the lattice dynamics of ZnO. It is found that Mn doping increases the lattice defects and induces two Raman vibration modes of 275 and 526cm−1. On the other hand, high temperature (TC higher than 350K) ferromagnetism is observed in Zn1−xMnxO (x⩽0.02) nanoparticles. It is found that the ferromagnetism of Zn1−xMnxO nanoparticles is strongly related to defects in ZnO.
Current-induced vortex nucleation and annihilation in vortex domain walls
Authors: Kläui M. , Laufenberg M. , Heyne L. , Backes D. , Rüdiger U. , Vaz C. A. F. , Bland J. A. C. , Heyderman L. J. , Cherifi S. , Locatelli A. , Mentes T. O. , Aballe L.
Published: June 2006

We report observations of the effect of electrical currents on the propagation and spin structure of vortex walls in NiFe wires. We find that magnetic vortices are nucleated and annihilated due to the spin torque effect. The velocity is found to be directly correlated with these transformations and decreases with increasing number of vortices. The transformations are observed in wide elements, while in narrower structures the propagation of single vortex walls prevails.
Exciton dissociation at the indium tin oxide-N,N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl) benzidine interface: A transient photovoltage study
Authors: Song Q. L. , Wu H. R. , Ding X. M. , Hou X. Y. , Li F. Y. , Zhou Z. G.
Published: June 2006

Transient photovoltage measured from the device of indium tin oxide (ITO)/N,N′-Bis(naphthalene-1-yl)-N,N′-bis(phenyl) benzidine (NPB) (600nm)∕Al (Al grounded) exhibits an abnormal polarity change from negative to positive upon pulsed laser irradiation. A simple model including interfacial exciton dissociation is proposed to describe the phenomenon observed. The initial negative signal is interpreted as a result of more electrons than holes injected into ITO by dissociation of excitons at the ITO-NPB interface, and the subsequent positive signal can be attributed to carrier separation by the built-in field in NPB. Further experiments confirm that it is the combination of interfacial exciton dissociation and built-in field that determines the polarity of the transient photovoltage. The amount of excitons dissociated at the ITO-NPB interface is much larger than that of free carriers created in other processes, with the ratio in the order of 103 for the device studied.
Organic solar cells with carbon nanotube network electrodes
Authors: Rowell Michael W. , Topinka Mark A. , McGehee Michael D. , Prall Hans-Jürgen , Dennler Gilles , Sariciftci Niyazi Serdar , Hu Liangbing , Gruner George
Published: June 2006

We fabricated flexible transparent conducting electrodes by printing films of single-walled carbon nanotube (SWNT) networks on plastic and have demonstrated their use as transparent electrodes for efficient, flexible polymer-fullerene bulk-heterojunction solar cells. The printing method produces relatively smooth, homogeneous films with a transmittance of 85% at 550nm and a sheet resistance (Rs) of 200Ω∕◻. Cells were fabricated on the SWNT/plastic anodes identically to a process optimized for ITO/glass. Efficiencies, 2.5% (AM1.5G), are close to ITO/glass and are affected primarily by Rs. Bending test comparisons with ITO/plastic show the SWNT/plastic electrodes to be far more flexible.
Detection of explosive materials by differential reflection spectroscopy
Authors: Hummel Rolf E. , Fuller Anna M. , Schöllhorn Claus , Holloway Paul H.
Published: June 2006

It is shown that traces of 2,4,6-trinitrotoluene (TNT) display strong and distinct structures in differential reflectograms, near 420 and 250nm. These characteristic peaks are not observed from moth balls, nail polish, polyvinyl chloride, starch, soap, paper, epoxy, aspirin, polycarbonate, aspartame, polystyrene, polyester, fertilizer, or sugar, to mention a few substances which may be in or on a suitcase. The described technique for detection of TNT is fast, inexpensive, reliable, and portable and does not require contact with the surveyed substance. Moreover, we have developed a curve recognition program for field applications of the technique. The origin of the spectra is discussed.
Surface-gated quantum Hall effect in an InAs heterostructure
Authors: Gelfand Ian J. , Amasha S. , Zumbühl D. M. , Kastner M. A. , Kadow C. , Gossard A. C.
Published: June 2006

We demonstrate low leakage surface gating of an indium arsenide heterostructure with the two-dimensional electron gas close to the surface. Gating is made possible by growing an aluminum oxide layer on top of the device. We find that the depletion point can be changed by applying a positive gate voltage and we see hysteresis when the voltage is swept below depletion.
Inversion domain boundaries and phase separation in p-AlGaN layers with high Al contents
Authors: Cho Hyung Koun , Kong Bo Hyun , Ren Z. , Han J. , Jeon S.-R.
Published: June 2006

The effect of Mg incorporation and Al composition on the formation of inversion domain boundaries (IDBs) and self-assembled superlattices in Mg-doped p-AlxGa1−xN epilayers grown on undoped Al0.3Ga0.7N was investigated by transmission electron microscopy. The formation, initiating position, and shape of the faceted IDBs strongly depended on the Mg and Al contents. Horizontally well-aligned self-assembled superlattices with large composition modulation by phase separation were also observed in the Mg-doped p-AlGaN before the formation of the faceted IDBs. The periodicity of the modulation obtained from the diffused streaks is ∼40Å.
Strong photoluminescence at 1.3μm with a narrow linewidth from nitridized InAs∕GaAs quantum dots
Authors: Jang Y. D. , Kim N. J. , Yim J. S. , Lee D. , Pyun S. H. , Jeong W. G. , Jang J. W.
Published: June 2006

Nitridized quantum dots (QDs) were prepared by metal-organic chemical vapor deposition. These QDs all showed strong photoluminescence (PL) emission at 1.3μm at room temperature, narrow spectral widths of 30meV, and large separations of 98meV between the ground and first excited states. Interestingly, the PL peak positions of the nitridized QDs were all around 1.3μm, despite the QDs having been prepared using significantly different amounts of nitrogen. Time-resolved PL revealed no electronic coupling between the QDs. These properties could potentially make these nitridized QDs very useful candidates for the fabrication of devices emitting at 1.3μm.
Enhancement of ultraviolet emissions from ZnO films by Ag doping
Authors: Duan Li , Lin Bixia , Zhang Weiying , Zhong Sheng , Fu Zhuxi
Published: June 2006

The Ag-doped ZnO films were deposited on Si substrates by dc reactive sputtering. Obvious enhancement of ultraviolet (UV) emission of the samples was observed due to Ag2O nanoclusters formatted during Ag doping. The UV emission consisted of two peaks. The 348nm peak was attributed to Ag2O nanoclusters, and the 382nm one was attributed to ZnO. The strongest UV emission of a certain ZnO–Ag2O film was over ten times stronger than that of a pure ZnO film, which was an exciting result. The enhancement of UV emission was caused by excitons formed at the interface between Ag2O nanoclusters and ZnO grains.
Surface roughness imaging using the acoustic emission induced by the dynamic radiation force of ultrasound
Authors: Mitri F. G. , Eberlein U. , Fatemi M.
Published: June 2006

High frequency ultrasound imaging systems are traditionally used in industry to obtain high resolution images of solid surfaces, and in some cases, to evaluate surface roughness. In this study we show that imaging fine surface roughness in the order of few microns is achievable at audio range frequencies (kilohertz range) by using the vibroacoustography (VA) technique. This technique allows one to image surface roughness on the basis of the ultrasound radiation force stimulated acoustic emission in a standing ultrasound wave field. Images obtained here demonstrate that VA may be used as a powerful tool for nondestructive inspection and imaging of surface roughness.
Surface roughness and strain effects on ZnO nanorod growth
Authors: Park S.-H. , Seo S.-Y. , Kim S.-H. , Han S.-W.
Published: June 2006

Vertically aligned ZnO nanorods were fabricated on Al2O3(001) substrates with various GaN interlayers by a catalyst-free metal-organic chemical vapor deposition. We observed that the shape and quality of ZnO nanorods grown on the GaN interlayers were considerably sensitive to the surface roughness of the interlayers. We also investigated orientation-dependent residual strain in the ZnO nanorods grown on Al2O3 substrates using polarized x-ray absorption fine structure (XAFS) measurements at Zn K edge. The XAFS revealed that the residual strain relaxation of Zn–O pairs in ab plane played a key role in the ZnO nanorod growth.
The role of waterholes as ‘refugia’ in sustaining genetic diversity and variation of two freshwater species in dryland river systems (Western Queensland, Australia)
Authors: CARINI G. , HUGHES J. M. , BUNN S. E.
Published: June 2006

1. Episodic floods and extended low or no flow periods characterise dryland river systems in Western Queensland, Australia. During protracted intervals between floods, rivers consist of a series of isolated waterholes, which serve as ‘refugia’ for aquatic species and much of the channel is dry. We categorised these waterholes into ‘main waterholes’, which are located in the main part of the river channel and ‘satellite waterholes’, which are located in distributary river channels.

2. We used mitochondrial sequences and allozymes to investigate levels of genetic diversity and patterns of connectivity among waterholes for two obligate freshwater species: Macrobrachium australiense (Decapoda: Palaemonidae) and Notopala sublineata (Gastropoda: Viviparidae).

3. We sampled 31 waterholes for M. australiense and 12 for N. sublineata. Based on a 505‐bp fragment of cytochrome oxidase subunit I, we identified 54 haplotypes in a sample of 232 individuals for M. australiense and based on a 457‐bp fragment of the same gene, 36 haplotypes in a sample of 145 individuals for N. sublineata.

4. Both nuclear and mitochondrial genetic data sets indicated that estimates of genetic diversity were not different in populations inhabiting main and satellite waterholes for either species. Also, there was generally very limited genetic differentiation among populations at any site.

5. We suggest that levels of connectivity among populations inhabiting waterholes at most sites are higher than expected. High levels of connectivity may help to maintain overall high levels of genetic diversity as well as low levels of genetic differentiation among waterholes within sites.
Does nitrogen become limiting under high‐P conditions in detritus‐based tropical streams?
Authors: STALLCUP LINDSAY A. , ARDÓN MARCELO , PRINGLE CATHERINE M.
Published: June 2006

1. We examined effects of nutrients on leaf breakdown in interior forest streams at La Selva Biological Station, Costa Rica. We tested the hypothesis that dissolved inorganic nitrogen (DIN) becomes limiting when ambient phosphorus (P) concentration is high. We also compared the breakdown of relatively ‘low quality’ leaves (lower C : N, Trema integerrima) with that of ‘higher quality’ leaves (higher C : N, Ficus insipida) in a high‐P stream.

2. Litterbags were incubated in two streams: one enriched experimentally with P [target concentration 200 μg soluble reactive phosphorus (SRP) L−1] and one control (naturally low P concentration approximately 10 μg SRP L−1). Ammonium enrichment was achieved by adding fertiliser upstream of half of the litterbags in each stream.

3. Phosphorus addition stimulated leaf breakdown, microbial respiration, ergosterol and leaf %P. Leaf breakdown rate was consistent with those in La Selva streams with naturally high P concentration.

4. Nitrogen (N) addition had no effect on leaf breakdown, microbial respiration, ergosterol or leaf chemistry in either the P‐enriched or the reference stream, in spite of low N : P ratios. We conclude that N is probably not limiting in streams at La Selva that are naturally high in P. This may be due to moderately high ambient N concentration (>200 μg DIN L−1) prevailing throughout the year.

5. The species with a lower C : N decomposed more rapidly and supported higher microbial activity than that with a higher C : N. Subtle differences in leaf N content, as well as dissolved P concentration, may be important in determining microbial colonisation and subsequent leaf breakdown.
Host recognition by a polyphagous lepidopteran (Helicoverpa armigera): primary host plants, host produced volatiles and neurosensory stimulation
Authors: RAJAPAKSE C. N. K. , WALTER G. H. , MOORE C. J. , HULL C. D. , CRIBB B. W.
Published: June 2006

Abstract An important question in the host‐finding behaviour of a polyphagous insect is whether the insect recognizes a suite or template of chemicals that are common to many plants? To answer this question, headspace volatiles of a subset of commonly used host plants (pigeon pea, tobacco, cotton and bean) and nonhost plants (lantana and oleander) of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) are screened by gas chromatography (GC) linked to a mated female H. armigera electroantennograph (EAG). In the present study, pigeon pea is postulated to be a primary host plant of the insect, for comparison of the EAG responses across the test plants. EAG responses for pigeon pea volatiles are also compared between females of different physiological status (virgin and mated females) and the sexes. Eight electrophysiologically active compounds in pigeon pea headspace are identified in relatively high concentrations using GC linked to mass spectrometry (GC‐MS). These comprised three green leaf volatiles [(2E)‐hexenal, (3Z)‐hexenylacetate and (3Z)‐hexenyl‐2‐methylbutyrate] and five monoterpenes (α‐pinene, β‐myrcene, limonene, E‐β‐ocimene and linalool). Other tested host plants have a smaller subset of these electrophysiologically active compounds and even the nonhost plants contain some of these compounds, all at relatively lower concentrations than pigeon pea. The physiological status or sex of the moths has no effect on the responses for these identified compounds. The present study demonstrates how some host plants can be primary targets for moths that are searching for hosts whereas the other host plants are incidental or secondary targets.
Microfibril‐associated Protein 4 Binds to Surfactant Protein A (SP‐A) and Colocalizes with SP‐A in the Extracellular Matrix of the Lung
Authors: Schlosser A. , Thomsen T. , Shipley J. M. , Hein P. W. , Brasch F. , Tornøe I. , Nielsen O. , Skjødt K. , Palaniyar N. , Steinhilber W. , McCormack F. X. , Holmskov U.
Published: June 2006

Pulmonary surfactant protein A (SP‐A) is an oligomeric collectin that recognizes lipid and carbohydrate moieties present on broad range of micro‐organisms, and mediates microbial lysis and clearance. SP‐A also modulates multiple immune‐related functions including cytokine production and chemotaxis for phagocytes. Here we describe the molecular interaction between the extracellular matrix protein microfibril‐associated protein 4 (MFAP4) and SP‐A. MFAP4 is a collagen‐binding molecule containing a C‐terminal fibrinogen‐like domain and a N‐terminal located integrin‐binding motif. We produced recombinant MFAP4 with a molecular mass of 36 and 66 kDa in the reduced and unreduced states respectively. Gel filtration chromatography and chemical crosslinking showed that MFAP4 forms oligomers of four dimers. We demonstrated calcium‐dependent binding between MFAP4 and human SP‐A1 and SP‐A2. No binding was seen to recombinant SP‐A composed of the neck region and carbohydrate recognition domain of SP‐A indicating that the interaction between MFAP4 and SP‐A is mediated via the collagen domain of SP‐A. Monoclonal antibodies directed against MFAP4 and SP‐A were used for immunohistochemical analysis, which demonstrates that the two molecules colocalize both on the elastic fibres in the interalveolar septum and in elastic lamina of pulmonary arteries of chronically inflamed lung tissue. We conclude, that MFAP4 interacts with SP‐A via the collagen region in vitro, and that MFAP4 and SP‐A colocates in different lung compartments indicating that the interaction may be operative in vivo.
Ex Vivo Responses for Interferon‐gamma and Proinflammatory Cytokine Secretion to Low‐Molecular‐Weight Antigen MTB12 of Mycobacterium tuberculosis during Human Tuberculosis
Authors: Lee J.‐S. , Son J. W. , Jung S.‐B. , Kwon Y.‐M. , Yang C.‐S. , Oh J.‐H. , Song C.‐H. , Kim H.‐J. , Park J.‐K. , Paik T.‐H. , Jo E.‐K.
Published: June 2006

MTB12 protein, also called CFP‐2, is a major and early secreted component of Mycobacterium tuberculosis. However, its role during mycobacterial infection has been poorly characterized. In this study, we purified the native MTB12 protein and investigated the profile of MTB12‐induced cytokines [interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α and interleukin (IL)‐6], in early tuberculosis (TB) patients (n = 20) and healthy controls (n = 35). The cytokine profiles were compared with those induced by the 30‐kDa antigen (Ag). In healthy controls, MTB12‐induced IFN‐γ production was markedly decreased in peripheral blood mononuclear cells compared with 30‐kDa Ag‐induced IFN‐γ. In TB patients, the mean IFN‐γ level induced by MTB12 was lower than that induced by the 30‐kDa Ag, albeit the difference was not significant. After 2 months of anti‐TB therapy, both the MTB12‐ and 30‐kDa‐induced IFN‐γ levels were significantly increased in TB patients. MTB12‐induced TNF‐α and IL‐6 levels were prominently upregulated in monocyte‐derived macrophages from TB patients, but they were not significantly different from those induced by the 30‐kDa Ag. Further, the activation of p38 mitogen‐activated protein kinase and extracellular signal‐regulated kinase was required for the induction of TNF‐α and IL‐6 by MTB12, as well as by the 30‐kDa Ag. Collectively, these data suggest that the MTB12 protein plays an essential role for proinflammatory responses through the MAPK pathway during the early stages of human TB, even though its T‐cell immunoreactivity is weaker than that of the 30‐kDa Ag.
Dynamic T‐lymphocyte Chemokine Receptor Expression Induced by Interferon‐beta Therapy in Multiple Sclerosis
Authors: Krakauer M. , Sorensen P. S. , Khademi M. , Olsson T. , Sellebjerg F.
Published: June 2006

Treatment with interferon (IFN)‐β reduces clinical disease activity in multiple sclerosis (MS). Using flow cytometry, an enzyme‐linked immunosorbent assay and a real‐time polymerase chain reaction, we studied in vivo IFN‐β‐induced effects on CD4+ T‐lymphocyte chemokine receptor expression as these influence central nervous system (CNS) transmigration and inflammation. At ‘steady state’ (≥1 day after the most recent IFN‐β injection), IFN‐β treatment increased CD4+ T‐cell surface expression of CC chemokine receptor (CCR)4, CCR5 and CCR7 after 3 months of treatment, whereas that of CXC chemokine receptor (CXCR)3 was unaltered. Conversely, at 9–12 h after the most recent IFN‐β injection, CCR4, CCR5 and CCR7 expressions were unaltered, while CXCR3 expression was reduced. CD4+ T‐cell surface expression of CCR4 was significantly lower in untreated MS patients compared with healthy volunteers. Of the plasma chemokines, only CXCL10 was increased by IFN‐β treatment; CCL3, CCL4, CCL5 and CXCL9 were unaltered. CCR5 mRNA expression in blood mononuclear cells correlated with the expression of T‐helper type 1 (Th1)‐associated genes whereas CCR4 and CCR7 mRNA expression correlated with Th2 and immunoregulatory genes. In conclusion, IFN‐β treatment caused ‘steady‐state’ increases of several chemokine receptors relevant for CD4+ T‐lymphocyte trafficking and function, possibly facilitating lymphocyte migration into the CNS. An important therapeutic effect of IFN‐β treatment may be the normalization of a decreased Th2‐related CD4+ T‐cell CCR4 expression in MS patients. Surface chemokine receptor expression and CXCL10 varied according to the timing of blood sampling in relation to the most recent IFN‐β injection. Thus, it is imperative to distinguish acute effects of IFN‐β from steady‐state effects.
IgA receptors in health and disease
Authors: Wines Bruce D. , Hogarth P. Mark
Published: June 2006

The varied interaction of the Fc region of IgA with receptors confers this antibody class with many of its unique properties. The epithelial polymeric Ig receptor on mucosal epithelial cells transports polymeric immunoglobulin A (pIgA) produced by mucosal B cells to the mucosal surface where, in complex with the secretory component (SC), this secretory immunoglobulin A (SIgA) excludes the multitude of dietary, environmental, and microbial antigens that continuously bombard the mucosae. In health, this IgA‐mediated exclusion not only forms the initial defence against infection, it also spares the systemic immune system from potentially deleterious responses to innocuous antigens which can otherwise culminate in inflammatory bowel disease or asthma. Beyond antigen exclusion, in closer encounters with antigens, IgA receptors play roles in protective immunity and disease. FcaRI is the principal myeloid IgA receptor and is responsible for differing IgA‐mediated effector responses such as respiratory burst, degranulation, and phagocytosis variously by granulyoctes, monocytes, and macrophages. Furthermore an unknown IgA receptor specific for the secretory component (SC) elicits powerful effector responses from eosinophils. On dendritic cells, FcaRI participates in antigen presentation while on microfold cells, key cells in mucosal antigen presentation, another unknown IgA receptor functions in the transport of antigens across the mucosal epithelial barrier. The activity of another uncharacterized IgA1/IgD receptor on T cells may affect autoimmune disorders. The interplay of different IgA receptors affects immune complex deposition in the common renal disease immunoglobulin A nephropathy (IgAN). Finally, the therapeutic application of various IgA receptors has been sought in the areas of infectious disease, vaccines, and cancer.
Synthesis of the photorespiratory key enzyme serine: glyoxylate aminotransferase in C. reinhardtii is modulated by the light regime and cytokinin
Authors: Tian Bao‐jing , Wang Yong , Zhu Ye‐rong , Lü Xian‐yu , Huang Kaiyao , Shao Ning , Beck Christoph F.
Published: June 2006

Serine:glyoxylate aminotransferase (SGAT) is a key enzyme of photorespiration. Changes in SGAT transcript levels and in enzyme activity following shifts from light to dark or dark to light and after cultivation in media supplemented with 6‐benzyladenine (6‐BA), a synthetic cytokinin, were analysed in the green alga Chlamydomonas reinhardtii. Cells grown in darkness had higher transcript levels than those grown in the light and transcript levels decreased upon transfer of cultures from dark to light; in contrast, they increased upon shift from light to dark. However, higher enzyme activities were detected in light‐grown vs. dark‐grown cells, which could be correlated with an elevated photorespiratory activity of the light‐grown cultures. Application of the synthetic cytokinin into the medium promoted both the accumulation of SGAT mRNA and enhanced SGAT enzyme activity. Under these conditions an accelerated multiplication of cells as well as higher final cell densities were observed. However, the synthetic cytokinin did not affect chlorophyll content, which is different from cytokinin effects observed in higher plants. The presence of cytokinin‐like activities in C. reinhardtii was confirmed using high‐performance liquid chromatography. One of these activities was identified by mass‐spectroscopy to be zeatin riboside.
Seasonal contrasting changes of foliar concentrations of terpenes and other volatile organic compound in four dominant species of a Mediterranean shrubland submitted to a field experimental drought and warming
Authors: Llusià Joan , Peñuelas Josep , Alessio Giorgio A. , Estiarte Marc
Published: June 2006

To test the effect of forecasted drought and warming conditions for the next decades by GCM and ecophysiological models on foliar concentrations of volatile organic compounds (VOCs) and especially of volatile terpenes, we studied four typical Mediterranean woody plants (Pinus halepensis L., Pistacia lentiscus L., Rosmarinus officinalis L. and Globularia alypum L.) under a field experimental drought and warming generated using automatically sliding curtains. Terpenes were detected in the four studied species (R. officinalis L., P halepensis L., Pistacia lentiscus L. and G. alypum L.). In general, maximum concentrations of terpenes were found in the coldest periods and minimum concentrations in the summer. Their concentrations ranged between 0.003 mg g−1 DM (eugenol) in G. alypum under drought conditions and 37 mg g−1 DM in R. officinalis under control conditions. Main volatile terpenes found in all studied species except in G. alypum were α‐pinene, camphene, β‐pinene, β‐phellandrene and caryophyllene. In general, VOC leaf concentrations increased when soil moisture increased and decreased when air temperature increased. However, contrasting not consistent responses to the drought and warming treatments were found among species, seasons and years. For example, in P. halepensis, the concentrations decreased in response to drought in winter and instead increased in summer. Contrarily, drought decreased concentrations in summer and increased them in winter in Pistacia lentiscus. In any case, the data on seasonal VOC concentration in Mediterranean woody species provided here will add new knowledge of seasonal variation in essential oil contents of these species. These data might help in the study of flammability of Mediterranean ecosystems and in improving prediction algorithms, inventories and modelling of monoterpene emissions in response to climate change, which mostly do not consider the changes in concentration under drought stress. However, the lack of general and consistent response patterns to increasing drought and warming among species, seasons and years found here makes this task difficult.
Characterization of single crystal silicon and electroplated nickel films by uniaxial tensile test with in situ X‐ray diffraction measurement
Authors: NAMAZU T. , INOUE S.
Published: June 2006

In this study, mechanical properties of micron‐thick single crystalline silicon (Si) and electroplated nickel (Ni) films at intermediate temperatures are investigated by means of X‐ray diffraction (XRD) tensile testing. The developed tensile test technique enables us to directly measure lateral (out‐of‐plane) elastic strain of microscale crystalline specimen using XRD during tensile loading, and determines Young's modulus, Poisson's ratio and tensile strength of the Si and Ni specimens. The specimens, measuring 10 μm thick, 300 μm wide and 3 mm long, are prepared through a conventional micro‐machining process, and the ultraviolet lithographie galvanoformung abformung (UV‐LIGA) process including a molding and an electroplating. The Si specimens, showing brittle fracture at room temperature (R.T.), have average Young's modulus and Poisson's ratio of 169 GPa and 0.35, respectively, in very good agreement with analytical values. The Ni specimens, showing ductile fracture, have those of 190 GPa and 0.24, lower than bulk coarse grained Ni. Young's moduli of both the Si and Ni specimens decrease with increasing temperature, but Poisson's ratios are independent of temperature. The influence of specimen size on elastic‐plastic properties of the specimens is discussed.