bluuebunny/crossref_metadata_2025 huggingface dataset:
Serine proteinase inhibitors in human skeletal muscle: Expression of β‐amyloid protein precursor and α1‐antichymotrypsin in vivo and during myogenesis in vitro
Authors: Akaaboune Mohammed , Verdière‐Sahuqué Martine , Lachkar Sylvie , Festoff Barry W. , Hantaï Daniel
Published: February 2005

The balance of serine proteases and inhibitors in nerve and muscle is altered during programmed‐ and injury‐induced remodeling. A serpin, α1‐antichymotrypsin (α1‐ACT), and Kunitz‐inhibitor containing forms of the β‐amyloid precursor protein (βAPP) may be important components of this balance. In the present study, we analyzed their expression in primary cultures of human myogenic (satellite) cells that mimic myogenic differentiation using Western blotting and immunocytochemistry. In vitro results were compared to in vivo results from normal adult human skeletal muscle biopsies. Using an anti‐α1‐ACT polyclonal antibody, we detected a 62 kDa immunoreactive band both in cultured human myogenic cells (mononucleated myoblasts as well as multi‐nucleated myotubes) and in extracts of human muscle biopsies. With a polyclonal anti‐βAPP antibody we found two bands (105 and 120 kDa) in myoblasts and myotubes in culture. However, the same antibody recognized only a single band at 92 kDa in biopsies. By immunocytochemistry, both α1‐ACT and βAPP were indistinctly present on localized to the surface of myoblasts in culture. In contrast, these inhibitors were dense on myotube surfaces, where they often formed distinct aggregates and frequently co‐localized. In permeabilized muscle cells, α1‐ACT and βAPP appeared to be localized to the perikarya of both myoblasts and myotubes. Confirming previous results, both α1‐ACT and βAPP were present at the neuromuscular junction in human muscle sections. These developmental changes found during in vitro myogenesis for α1‐ACT and βAPP, both serine protease inhibitors, reinforce the hypothesis that regulation of the serine proteases and serine protease inhibitors plays an important role in neuromuscular differentiation. © 1995 Wiley‐Liss Inc.
Prostaglandin E2 regulates production of plasminogen activator isoenzymes, urokinase receptor, and plasminogen activator inhibitor‐1 in primary cultures of rat calvarial osteoblasts
Authors: Allan Elizabeth H. , Martin T. John
Published: February 2005

The bone resorbing agent, prostaglandin E2 (PGE2), was found to alter several components of the plasminogen activator (PA)/plasmin pathway in primary cultures of rat neonatal osteoblast‐like cells. The mRNA and activities of both urokinase‐type PA (uPA) and tissue‐type PA (tPA) were enhanced by PGE2 treatment. The presence of mRNA for the uPA receptor (uPAR) has been demonstrated in these cells and steady‐state levels shown to be greatly enhanced, the response being rapid and sustained for at least 24 hours. mRNA for plasminogen activator inhibitor 1 (PAI‐1) was modulated in a biphasic manner, with inhibition of the constitutive level apparent at 4 hours of treatment and stimulation apparent at 12 hours and longer, while PAI‐1 protein, measured by an ELISA assay for rat PAI‐1, was diminished over this period. Neither PAI‐2 mRNA nor mRNA for the broad spectrum protease inhibitor, protease nexin‐1 (PN‐1), was found to be modulated by PGE2. Therefore, PGE2 is likely to stimulate cell surface proteolytic activity, since uPA mRNA and cell‐associated activity were elevated, as was mRNA for the cellular receptor for uPA. Although it was not possible to measure uPAR number and affinity it seems likely that elevated uPAR mRNA would translate into increased uPARs which would localize the increased uPA activity to the pericellular region. tPA mRNA and activity were also increased transiently with the activity inhibited with prolonged incubations, apparently by PAI‐1. Elevation of tPA mRNA and activity may result in elevated activity within the extracellular matrix as tPA has been reported to associate with several matrix proteins. Thus the early effect of PGE2 would be to promote proteolysis, both pericellularly and in the extracellular matrix. The inhibition of PAI‐1 mRNA and protein, which would contribute to the elevation of activity, is due to PGE2, but the later stimulatory effect on PAI‐1 mRNA may be due to feedback regulation by transforming growth factor beta (TGFβ), secreted by osteoblasts and activated by elevated levels of PA. © 1995 Wiley‐Liss Inc.
IL‐3 and ribavirin induce differentiation and growth suppression during long‐term treatment of a megakaryocytic leukemia cell line
Authors: Majumdar Alokes , Kerby Stephen , Mullikin Brian , Beckstead Jay H. , Stenberg Paula E. , Seidman Michael M.
Published: February 2005

Differentiation of the megakaryocytic leukemia cells, CMK, was induced by long‐term (12 day) treatment with the combination of IL‐3 and the nucleoside analogue ribavirin (RV), which reduces cellular GTP levels. In a previous report we demonstrated the induction of early messages and antigens, as well as the formation of giant polyploid cells in the cultures (Majumdar et al., 1994, J. Cell. Physiol., 160:29–39). Here we show high level induction of messages for the late markers, Platelet Factor 4, GMP140 (P‐Selectin), thrombospondin, and beta thromboglobulin. The induced cells are also positive for these antigens by immunocytochemical analysis. The high level message induction resulted from synergy between the inducers. Pretreatment of the cells with IL‐3 could accelerate the rise in message seen with the inducer combination. The increase in differentiation markers was accompanied by a reduction of the proliferative capacity of the cells. Riboguanosine, which has anti differentiation activity, blocked the induction of early and late antigens by the inducer combination, and also by IL‐3 acting alone, but did not block the reduction in proliferative competence. In this model of megakaryocytic differentiation IL‐3 treatment yields and initial stimulation of growth followed by growth supperssion, and is the principal driver of the differentiation process. RV functions primarily as a stimulator of message and protein expression in synergy with IL‐3. © 1995 Wiley‐Liss Inc.
Exogenous nitric oxide elicits chemotaxis of neutrophils in vitro
Authors: Beauvais Francis , Michel Laurence , Dubertret Louis
Published: February 2005

Nitric oxide (NO) has been shown to be both an intercellular and intracellular messenger. We propose here that exogenous NO induces chemotactic locomotion of human neutrophils. Indeed, when human neutrophils were placed in a gradient of a nitric oxide donor (S‐nitroso‐N‐acetylpenicillamine; SNAP), a directed locomotion was induced, as evidenced by experiments of chemotaxis under agarose. Degraded SNAP (i.e., SNAP solution which had previously released NO) did not induce directed locomotion. Moreover, oxyhemoglobin, a scavenger of free NO, suppressed the chemotactic effect of SNAP, whereas LY‐83583, a soluble guanylate cyclase inhibitor, inhibited the SNAP‐mediated chemotaxis in a dose‐response manner. Other unrelated NO donors, SIN‐1 and S‐nitroso‐cysteine—a natural S‐nitroso‐compound, also induced a directed locomotion of neutrophils. Taken together, these in vitro experiments indicate that exogenous NO could mediate the chemotaxis of neutrophils and thus suggest that NO could contribute to neutrophil recruitment in vivo. © 1995 Wiley‐Liss Inc.
Interleukin‐10 selectively inhibits osteoclastogenesis by inhibiting differentiation of osteoclast progenitors into preosteoclast‐like cells in rat bone marrow culture system
Authors: Xu Li Xin , Kukita Toshio , Kukita Akiko , Otsuka Takeshi , Niho Yoshiyuki , Iijima Tadahiko
Published: February 2005

Recombinant human interleukin‐10 (hIL‐10) inhibited the formation of osteoclast‐like multinucleated cells in rat whole bone marrow cultures. The effect of hIL‐10 on the process of osteoclast formation was further examined, since the process of osteoclast formation includes the proliferation and the differentiation of osteoclast progenitors into mononuclear preosteoclasts and the fusion of preosteoclasts into multinucleated osteoclasts. In the nonadherent bone marrow cell culture system, which was free of stromal cells and formed preosteoclast‐like cells, hIL‐10 significantly inhibited the formation of preosteoclast‐like cells even at a very low concentration (0.5 U/ml). The strong inhibition appeared even after treatment with hIL‐10 for only the first 24 h of the culture. However, hIL‐10 did not affect the fusion process of preosteoclast‐like cells to form osteoclast‐like multinucleated cells in the rat coculture system of preosteoclast‐like cells with primary osteo‐blasts. Furthermore, hIL‐10 completely inhibited the colony formation induced by granulocyte macrophage colony‐stimulating factor (GM‐CSF). These findings suggest that the inhibition of osteoclastogenesis by hIL‐10 started at the early stage of the differentiation of osteoclast progenitors to preosteoclasts. © 1995 Wiley‐Liss Inc.
Heparin binding, internalization, and metabolism in vascular smooth muscle cells: I. Upregulation of heparin binding correlates with antiproliferative activity
Authors: Letourneur Didier , Caleb Benjamin L. , Castellot John J.
Published: February 2005

Vascular smooth muscle cell (SMC) hyperplasia is an important component in the pathogenesis of arteriosclerotic lesions and is responsible for the failure of many vascular surgical procedures. SMC proliferation is inhibited by the glycosaminoglycan heparin; however, the precise mechanisms of action are still not understood. One important question in this regard is whether binding, internalization, and metabolism of heparin are necessary for the antiproliferative activity. In this study, we have analyzed SMC rendered resistant to the antiproliferative effect of heparin by drug selection and retroviral infection of SMC. We first examined the ability of heparin to bind to SMC. Experiments using [3H]heparin indicate the presence of saturable, heparin‐displaceable, protease‐sensitive binding sites on both sensitive and resistant SMC. The affinity of heparin binding does not correlate with the antiproliferative response. Using fluorescent and radiolabeled heparin probes, we observed that early heparin internalization kinetics in both sensitive and resistant SMC is similar, indicating that resistanace to heparin is not due to changes in the ability of cells to take up heparin. In contrast, we observed during the continuous incubation with heparin that binding to resistant SMC is rapidly downregulated, whereas sensitive cells continue to bind and internalize heparin. These results suggest that upregulation of heparin binding to the SMC surface is required for an antiproliferative response. In an accompanying paper (Letourneur et al. [1995] J. Cell. Physiol., 165:687–695, this issue), we describe the degradation and secretion of internalized heparin in both sensitive and resistant SMC. © 1995 Wiley‐Liss Inc.
Efficacy and safety of botulinum type A toxin (Dysport) in cervical dystonia: Results of the first US randomized, double‐blind, placebo‐controlled study
Authors: Truong Daniel , Duane Drake D. , Jankovic Joseph , Singer Carlos , Seeberger Lauren C. , Comella Cynthia L. , Lew Mark F. , Rodnitzky Robert L. , Danisi Fabio O. , Sutton James P. , Charles P. David , Hauser Robert A. , Sheean Geoffrey L.
Published: February 2005

Botulinum toxin type A (Dysport) has been shown in European studies to be a safe and effective treatment for cervical dystonia. This multicenter, double‐blind, randomized, controlled trial assessed the safety and efficacy of Dysport in cervical dystonia patients in the United States. Eighty patients were randomly assigned to receive one treatment with Dysport (500 units) or placebo. Participants were followed up for 4 to 20 weeks, until they needed further treatment. They were assessed at baseline and weeks 2, 4, 8, 12, 16, and 20 after treatment. Dysport was significantly more efficacious than placebo at weeks 4, 8, and 12 as assessed by the Toronto Western Spasmodic Torticollis Rating Scale (10‐point vs. 3.8‐point reduction in total score, respectively, at week 4; P ≤ 0.013). Of participants in the Dysport group, 38% showed positive treatment response, compared to 16% in the placebo group (95% confidence interval, 0.02–0.41). The median duration of response to Dysport was 18.5 weeks. Side effects were generally similar in the two treatment groups; only blurred vision and weakness occurred significantly more often with Dysport. No participants in the Dysport group converted from negative to positive antibodies after treatment. These results confirm previous reports that Dysport (500 units) is safe, effective, and well‐tolerated in patients with cervical dystonia. © 2005 Movement Disorder Society
Arachidonate activation of protein kinase C may be involved in the stimulation of protein synthesis by insulin in L6 myoblasts
Authors: Thompson Michael G. , Acamovic Fiona , Mackie Steven C. , Morrison Kenneth S. , Palmer Robert M.
Published: February 2005

Insulin stimulated protein synthesis in L6 myoblasts but did not increase the labelling of DAG or the release of phosphocholine from phosphatidylcholine. The DAG lipase inhibitor, RHC 80267, more than doubled the amount of label appearing in DAG but did not stimulate protein synthesis. Even in the presence of the DAG lipase inhibitor insulin failed to have any effect on DAG labelling, and conversely RHC 80267 did not modify the insulin-induced increase in protein synthesis. These results suggest that endogenous DAG production is not involved in the stimulation of protein synthesis by insulin. However, exogenous diacylglycerols (1-oleoyl-2-acetyl glycerol and 1-stearoyl-2-arachidonoyl glycerol) both stimulated protein synthesis in L6 myoblasts. The efficacy of the former (arachidonatefree) DAG suggested that their action was by activation of protein kinase C rather than by arachidonate release and prostaglandin formation. Ibuprofen, an inhibitor of cyclo-oxygenase failed to block the effects of insulin whereas a second cyclo-oxygenase inhibitor, indomethacin had only a partial inhibitory effect. The protein kinase C (PKC) inhibitor, RO-31-8220, totally blocked the effect of insulin. Since indomethacin is also recognised to inhibit phospholipase A2, the data suggests that insulin acts on protein synthesis in myoblasts by arachidonate activation of PKC.
Normalising the associative law: An experiment with Martin-Löf's type theory
Authors: Hedberg Michael
Published: February 2005

Martin-Löf's type theory contains a logic, a specification language and a programming language, so it is a tool with different uses. Although it is traditionally used as anintegratedprogramming logic, it may well be used as anexternallogic, which is necessary if one wants to use the formalism of type theory to verify the correctness of an external program. Different tools, such as well founded recursion, measure functions, or the separation of correctness into termination and partial correctness, may be used to obtain a correct type theory program. Type theory is viewed as anopensystem with respect toinductively definedtypes and predicates, which makes it easy to represent an external program as agraph. Formal proofs have been edited using Larry Paulson's ISABELLE.
Putin’s Etatization project and limits to democratic reforms in Russia☆
Authors: Hashim S. Mohsin
Published: February 2005

The paper evaluates Putin’s state building efforts in terms of its impact on democratic change in Russia. Putin’s evolution is treated as a response and not a solution to the legacy of the Yeltsin era reforms that created a politico-economic system lacking widespread legitimacy. It is argued that Putin’s consolidation of power through his centralization measures seriously undermines Russia’s prospects for democratization. The paper analyzes his efforts to wrest authority away from regional leaders, oligarchs, parliament and civil society. The analysis contends that concentration of state power in the absence of horizontal accountability and an effective state bureaucracy will only consolidate a non-democratic regime incapable of implementing its proclaimed public policy goals.
Development of sensitivity to visual motion in macaque monkeys
Authors: KIORPES LYNNE , MOVSHON J. ANTHONY
Published: February 2005

The development of spatial vision is relatively well documented in human and nonhuman primates. However, little is known about the development of sensitivity to motion. We measured the development of sensitivity to direction of motion, and the relationship between motion and contrast sensitivity in macaque monkeys as a function of age. Monkeys (Macaca nemestrina, aged between 10 days and 3 years) discriminated direction of motion in random-dot kinematograms. The youngest monkeys showed directionally selective orienting and the ability to integrate motion signals at large dot displacements and fast speeds. With age, coherence sensitivity improved for all spatial and temporal dot displacements tested. The temporal interval between the dots was far less important than the spatial offset in determining the animals' performance at all but the youngest ages. Motion sensitivity improved well beyond the end of the first postnatal year, when mid-spatial-frequency contrast sensitivity reached asymptote, and continued for at least 3 years. Sensitivity to contrast at high spatial frequencies also continued to develop beyond the end of the first year. We conclude that the development of motion sensitivity depends on mechanisms beyond the low-level filters presumed to limit acuity and contrast sensitivity, and most likely reflects the function of extrastriate visual areas.
Visual pigment composition in zebrafish: Evidence for a rhodopsin–porphyropsin interchange system
Authors: ALLISON W. TED , HAIMBERGER THEODORE J. , HAWRYSHYN CRAIG W. , TEMPLE SHELBY E.
Published: February 2005

Numerous reports have concluded that zebrafish (Danio rerio) possesses A1-based visual pigments in their rod and cone photoreceptors. In the present study, we investigated the possibility that zebrafish have a paired visual pigment system. We measured the spectral absorption characteristics of photoreceptors from zebrafish maintained in different temperature regimes and those treated with exogenous thyroid hormone using CCD-based microspectrophotometry. Rods from fish housed at 15°C and 28°C were not significantly different, having λmaxvalues of 503 ± 5 nm (n= 106) and 504 ± 6 nm (n= 88), respectively. Thyroid hormone treatment (held at 28°C), however, significantly shifted the λmaxof rods from 503 ± 5 nm (n= 194) to 527 ± 8 nm (n= 212). Cone photoreceptors in fish housed at 28°C (without thyroid hormone treatment) had λmaxvalues of 361 ± 3 nm (n= 2) for ultraviolet-, 411 ± 5 nm (n= 18) for short-, 482 ± 6 nm (n= 9) for medium-, and 565 ± 10 nm (n= 14) for long-wavelength sensitive cones. Thyroid hormone treatment of fish held at 28°C significantly shifted the λmaxof long-wavelength sensitive cones to 613 ± 11 nm (n= 20), substantially beyond that of the λmaxof the longest possible A1-based visual pigment (∼580 nm). Thyroid hormone treatment produced smaller shifts of λmaxin other cone types and increased the half-band width. All shifts in photoreceptor λmaxvalues resulting from thyroid hormone treatment matched predictions for an A1- to A2-based visual pigment system. We therefore conclude that zebrafish possess a rhodopsin–porphyropsin interchange system that functions to spectrally tune rod and cone photoreceptors. We believe that these observations should be carefully considered during analysis of zebrafish spectral sensitivity.
Origin of depleted components in basalt related to the Hawaiian hot spot: Evidence from isotopic and incompatible element ratios
Authors: Frey F. A. , Huang S. , Blichert‐Toft J. , Regelous M. , Boyet M.
Published: February 2005

The radiogenic isotopic ratios of Sr, Nd, Hf, and Pb in basaltic lavas associated with major hot spots, such as Hawaii, document the geochemical heterogeneity of their mantle source. What processes created such heterogeneity? For Hawaiian lavas there has been extensive discussion of geochemically enriched source components, but relatively little attention has been given to the origin of depleted source components, that is, components with the lowest 87Sr/86Sr and highest 143Nd/144Nd and 176Hf/177Hf. The surprisingly important role of a depleted component in the source of the incompatible element‐enriched, rejuvenated‐stage Hawaiian lavas is well known. A depleted component also contributed significantly to the ∼76–81 Ma lavas erupted at Detroit Seamount in the Emperor Seamount Chain. In both cases, major involvement of MORB‐related depleted asthenosphere or lithosphere has been proposed. Detroit Seamount and rejuvenated‐stage lavas, however, have important isotopic differences from most Pacific MORB. Specifically, they define trends to relatively unradiogenic Pb isotope ratios, and most Emperor Seamount lavas define a steep trend of 176Hf/177Hf versus 143Nd/144Nd. In addition, lavas from Detroit Seamount and recent rejuvenated‐stage lavas have relatively high Ba/Th, a characteristic of lavas associated with the Hawaiian hot spot. It is possible that a depleted component, intrinsic to the hot spot, has contributed to these young and old lavas related to the Hawaiian hot spot. The persistence of such a component over 80 Myr is consistent with a long‐lived source, i.e., a plume.
Halogens in the coastal snow pack near Barrow, Alaska: Evidence for active bromine air‐snow chemistry during springtime
Authors: Simpson William R. , Alvarez‐Aviles Laura , Douglas Thomas A. , Sturm Matthew , Domine Florent
Published: February 2005

We measured halide concentrations of snow and frost flowers in the vicinity of Barrow, Alaska. We find that the ratio of bromide to sodium in frost flowers is slightly enhanced (≈10%) as compared to sea water. In contrast, the ratio of bromide to sodium in some snow samples is more than an order of magnitude enhanced, and in other samples is more than an order of magnitude depleted. We interpret the bromide depleted snow as having been processed by heterogeneous chemistry and providing reactive halogen compounds to the atmosphere. The eventual end product of reactive bromine chemistry is HBr that is then deposited over a wide region, enhancing bromide in inland snow samples. Although frost flowers or open leads are likely to be the original source of halides that become reactive halogen gases, we find that the bromide release often occurs subsequent to production of aerosol from marine sources.
The surface of maximum wind as an alternative to the isobaric surface for wind climatology
Authors: Strong Courtenay , Davis Robert E.
Published: February 2005

The surface of maximum wind (SMW) is introduced as an analysis frame for climate studies of fast upper tropospheric winds. As defined here, the vertical domain for the SMW includes the troposphere above 500 hPa and upper tropospheric jet streams that may protrude into the lower stratosphere. We use NCEP‐NCAR Reanalysis data for summers 1958–2004 in the vicinity of the tropical easterly jet (TEJ) to show how the spatial and temporal variability of the SMW relate to jet stream cores and the tropopause. We then compare the SMW climatology of the TEJ to an isobaric climatology of the TEJ, demonstrating that the SMW climatology reveals descent and slowing of the TEJ over the period of record, whereas the isobaric climatology provides only an overestimate of the TEJ slowing trend.
Propagation of the 12 May 1997 interplanetary coronal mass ejection in evolving solar wind structures
Authors: Odstrcil D. , Pizzo V. J. , Arge C. N.
Published: February 2005

Recently, we simulated the 12 May 1997 coronal mass ejection (CME) event with a numerical three‐dimensional magnetohydrodynamic model (Odstrcil et al., 2004), in which the background solar wind was determined from the Science Applications International Corporation (SAIC) coronal model (Riley et al., 2001) and the transient disturbance was determined from the cone model (Zhao et al., 2002). Although we reproduced with some fidelity the arrival of the shock and interplanetary CME at Earth, detailed analysis of the simulations showed a poorly defined shock and discrepancies in the standoff distance between the shock and the driving ejecta and in the inclination of the shock with respect to the Sun‐Earth line. In this paper, we investigate these problems in more detail. First, we use an alternative coronal outflow model, the so‐called Wang‐Sheeley‐Arge‐Mount Wilson Observatory (WSA‐MWO) model (Arge and Pizzo, 2000; Arge et al., 2002; Arge et al., 2004), to assess the effect of using synoptic, full rotation coronal maps that differ in method of preparation. Second, we investigate how differences in the presumed evolution of the coronal stream structure affect the propagation of the disturbance. We incorporate two time‐dependent boundary conditions for the ambient solar wind as determined by the WSA model, one derived from pseudo daily updated maps and one derived from artificially modified full rotation maps. Numerical results from these different scenarios are compared with solar wind observations at Earth. We find that heliospheric simulations with the SAIC and WSA full rotation models provide qualitatively similar parameters of the background solar wind and transient disturbances at Earth. Improved agreement with the observations is achieved by artificially modified maps that simulate the rapid displacement of the coronal hole boundary after the CME eruption. We also consider how multipoint temporal profiles of solar wind parameters and multiperspective synthetic white light images emulating upcoming STEREO spacecraft observations might be used to differentiate between different event scenarios.
Interaction of NH(XΣ−3) with He: Potential energy surface, bound states, and collisional Zeeman relaxation
Authors: Cybulski H. , Krems R. V. , Sadeghpour H. R. , Dalgarno A. , Kłos J. , Groenenboom G. C. , van der Avoird A. , Zgid D. , Chałasiński G.
Published: February 2005

A detailed analysis of the He–NH(Σ−3) van der Waals complex is presented. We discuss ab initio calculations of the potential energy surface and fitting procedures with relevance to cold collisions, and we present accurate calculations of bound energy levels of the triatomic complex as well as collisional properties of NH molecules in a buffer gas of He3. The influence of the external magnetic field used to trap the NH molecules and the effect of the atom–molecule interaction potential on the collisionally induced Zeeman relaxation are explored. It is shown that minute variations of the interaction potential due to different fitting procedures may alter the Zeeman relaxation rate at ultralow temperatures by as much as 50%.
Dynamic properties of microemulsions modified with homopolymers and diblock copolymers: The determination of bending moduli and renormalization effects
Authors: Holderer Olaf , Frielinghaus Henrich , Byelov Dmytro , Monkenbusch Michael , Allgaier Jürgen , Richter Dieter
Published: February 2005

The properties of bicontinuous microemulsions, consisting of water, oil, and a surfactant, can be modified by the addition of diblock copolymers (boosting effect) and homopolymers (inverse boosting effect) or a combination of both. Here, the influence of the addition of homopolymers (PEPX and PEOX, X=5k or 10k molecular weight) on the dynamics of the surfactant layer is studied with neutron spin echo spectroscopy (NSE). Combining the results with the previous findings for diblock copolymers allows for a better separation of viscosity and bending modulus effects. With the addition of homopolymers, a significant increase of the relaxation rate compared to the pure microemulsion has been observed. The influence on the bending rigidity κ is measured with NSE experiments. Homopolymer addition reduces κ by up to Δκ≃−0.5kBT, whereas the diblock copolymer yields an increase of κ by ∼0.3kBT. Comparison of the bending moduli that are obtained by analysis of the dynamics to those obtained from small angle neutron scattering (SANS) sheds light on the different renormalization length scales for NSE and SANS. Variation of the surfactant concentration at otherwise constant conditions of homopolymer or diblock-copolymer concentration shows that NSE results are leading to the pure bending rigidity, while the renormalized one is measured with SANS.
Effect of force control algorithms on the scanning probe microscope lithography system
Authors: Yen Jia-Yush , Lin I-Ming , Lee Chih-Kung
Published: February 2005

This letter addresses the servo issue in the scanning probe microscope (SPM) lithography. The performance of the probe controller affects the ability of the lithography system to form uniform marks on the sample surface. Different control algorithms are tested on a commercial SPM system. The tests include the controller from the original system, a proportional integral differential controller, and a modern μ controller. The design procedure for the μ controller is described. The experimental results show that carefully tuned controllers are able to suppress the undesirable vibrations, and the μ controller achieves the most uniform lithography marks.
Fourier transform infrared spectroscopy for Mars science
Authors: Anderson Mark S. , Andringa Jason M. , Carlson Robert W. , Conrad Pamela , Hartford Wayne , Shafer Michael , Soto Alejandro , Tsapin Alexandre I. , Dybwad Jens Peter , Wadsworth Winthrop , Hand Kevin
Published: February 2005

Presented here is a Fourier transform infrared spectrometer (FTIR) for field studies that serves as a prototype for future Mars science applications. Infrared spectroscopy provides chemical information that is relevant to a number of Mars science questions. This includes mineralogical analysis, nitrogen compound recognition, truth testing of remote sensing measurements, and the ability to detect organic compounds. The challenges and scientific opportunities are given for the in situ FTIR analysis of Mars soil and rock samples. Various FTIR sampling techniques are assessed and compared to other analytical instrumentation. The prototype instrument presented is capable of providing field analysis in a Mars analog Antarctic environment. FTIR analysis of endolithic microbial communities in Antarctic rocks and a Mars meteor are given as analytical examples.
Constitutively Elevated Salicylic Acid Signals Glutathione-Mediated Nickel Tolerance in Thlaspi Nickel Hyperaccumulators
Authors: Freeman John L. , Garcia Daniel , Kim Donggiun , Hopf Amber , Salt David E.
Published: February 2005

Progress is being made in understanding the biochemical and molecular basis of nickel (Ni)/zinc (Zn) hyperaccumulation in Thlaspi; however, the molecular signaling pathways that control these mechanisms are not understood. We observed that elevated concentrations of salicylic acid (SA), a molecule known to be involved in signaling induced pathogen defense responses in plants, is a strong predictor of Ni hyperaccumulation in the six diverse Thlaspi species investigated, including the hyperaccumulators Thlaspi goesingense, Thlaspi rosulare, Thlaspi oxyceras, and Thlaspi caerulescens and the nonaccumulators Thlaspi arvense and Thlaspi perfoliatum. Furthermore, the SA metabolites phenylalanine, cinnamic acid, salicyloyl-glucose, and catechol are also elevated in the hyperaccumulator T. goesingense when compared to the nonaccumulators Arabidopsis (Arabidopsis thaliana) and T. arvense. Elevation of free SA levels in Arabidopsis, both genetically and by exogenous feeding, enhances the specific activity of serine acetyltransferase, leading to elevated glutathione and increased Ni resistance. Such SA-mediated Ni resistance in Arabidopsis phenocopies the glutathione-based Ni tolerance previously observed in Thlaspi, suggesting a biochemical linkage between SA and Ni tolerance in this genus. Intriguingly, the hyperaccumulator T. goesingense also shows enhanced sensitivity to the pathogen powdery mildew (Erysiphe cruciferarum) and fails to induce SA biosynthesis after infection. Nickel hyperaccumulation reverses this pathogen hypersensitivity, suggesting that the interaction between pathogen resistance and Ni tolerance and hyperaccumulation may have played a critical role in the evolution of metal hyperaccumulation in the Thlaspi genus.
Aquaporins of the PIP2 Class Are Required for Efficient Anther Dehiscence in Tobacco
Authors: Bots Marc , Vergeldt Frank , Wolters-Arts Mieke , Weterings Koen , van As Henk , Mariani Celestina
Published: February 2005

Several processes during sexual reproduction in higher plants involve the movement of water between cells or tissues. Before flower anthesis, anther and pollen dehydration takes place before the release of mature pollen at dehiscence. Aquaporins represent a class of proteins that mediates the movement of water over cellular membranes. Aquaporins of the plasmamembrane PIP2 family are expressed in tobacco (Nicotiana tabacum) anthers and may therefore be involved in the movement of water in this organ. To gain more insight into the role these proteins may play in this process, we have analyzed their localization using immunolocalizations and generated plants displaying RNA interference of PIP2 aquaporins. Our results indicate that PIP2 protein expression is modulated during anther development. Furthermore, in tobacco PIP2 RNA interference plants, anther dehydration was slower, and dehiscence occurred later when compared with control plants. Together, our results suggest that aquaporins of the PIP2 class are required for efficient anther dehydration prior to dehiscence.
Molecular and Biochemical Characterization of 2-Hydroxyisoflavanone Dehydratase. Involvement of Carboxylesterase-Like Proteins in Leguminous Isoflavone Biosynthesis
Authors: Akashi Tomoyoshi , Aoki Toshio , Ayabe Shin-ichi
Published: February 2005

Isoflavonoids are ecophysiologically active secondary metabolites of the Leguminosae and known for health-promoting phytoestrogenic functions. Isoflavones are synthesized by 1,2-elimination of water from 2-hydroxyisoflavanones, the first intermediate with the isoflavonoid skeleton, but details of this dehydration have been unclear. We screened the extracts of repeatedly fractionated Escherichia coli expressing a Glycyrrhiza echinata cDNA library for the activity to convert a radiolabeled precursor into formononetin (7-hydroxy-4′-methoxyisoflavone), and a clone of 2-hydroxyisoflavanone dehydratase (HID) was isolated. Another HID cDNA was cloned from soybean (Glycine max), based on the sequence information in its expressed sequence tag library. Kinetic studies revealed that G. echinata HID is specific to 2,7-dihydroxy-4′-methoxyisoflavanone, while soybean HID has broader specificity to both 4′-hydroxylated and 4′-methoxylated 2-hydroxyisoflavanones, reflecting the structures of isoflavones contained in each plant species. Strikingly, HID proteins were members of a large carboxylesterase family, of which plant proteins form a monophyletic group and some are assigned defensive functions with no intrinsic catalytic activities identified. Site-directed mutagenesis with soybean HID protein suggested that the characteristic oxyanion hole and catalytic triad are essential for the dehydratase as well as the faint esterase activities. The findings, to our knowledge, represent a new example of recruitment of enzymes of primary metabolism during the molecular evolution of plant secondary metabolism.
Control of Sodium Transport in Durum Wheat
Authors: Davenport Romola , James Richard A. , Zakrisson-Plogander Anna , Tester Mark , Munns Rana
Published: February 2005

In many species, salt sensitivity is associated with the accumulation of sodium (Na+) in photosynthetic tissues. Na+ uptake to leaves involves a series of transport steps and so far very few candidate genes have been implicated in the control of these processes. In this study, Na+ transport was compared in two varieties of durum wheat (Triticum turgidum) L. subsp. durum known to differ in salt tolerance and Na+ accumulation; the relatively salt tolerant landrace line 149 and the salt sensitive cultivar Tamaroi. Genetic studies indicated that these genotypes differed at two major loci controlling leaf blade Na+ accumulation (R. Munns, G.J. Rebetzke, S. Husain, R.A. James, R.A. Hare [2003] Aust J Agric Res 54: 627–635). The physiological traits determined by these genetic differences were investigated using measurements of unidirectional 22Na+ transport and net Na+ accumulation. The major differences in Na+ transport between the genotypes were (1) the rate of transfer from the root to the shoot (xylem loading), which was much lower in the salt tolerant genotype, and (2) the capacity of the leaf sheath to extract and sequester Na+ as it entered the leaf. The genotypes did not differ significantly in unidirectional root uptake of Na+ and there was no evidence for recirculation of Na+ from shoots to roots. It is likely that xylem loading and leaf sheath sequestration are separate genetic traits that interact to control leaf blade Na+.
A Novel Dwarfing Mutation in a Green Revolution Gene from Brassica rapa
Authors: Muangprom Amorntip , Thomas Stephen G. , Sun Tai-ping , Osborn Thomas C.
Published: February 2005

Mutations in the biosynthesis or signaling pathways of gibberellin (GA) can cause dwarfing phenotypes in plants, and the use of such mutations in plant breeding was a major factor in the success of the Green Revolution. DELLA proteins are GA signaling repressors whose functions are conserved in different plant species. Recent studies show that GA promotes stem growth by causing degradation of DELLA proteins via the ubiquitin-proteasome pathway. The most widely utilized dwarfing alleles in wheat (Triticum aestivum; e.g. Rht-B1b and Rht-D1b) encode GA-resistant forms of a DELLA protein that function as dominant and constitutively active repressors of stem growth. All of the previously identified dominant DELLA repressors from several plant species contain N-terminal mutations. Here we report on a novel dwarf mutant from Brassica rapa (Brrga1-d) that is caused by substitution of a conserved amino acid in the C-terminal domain of a DELLA protein. Brrga1-d, like N-terminal DELLA mutants, retains its repressor function and accumulates to high levels, even in the presence of GA. However, unlike wild-type and N-terminal DELLA mutants, Brrga1-d does not interact with a protein component required for degradation, suggesting that the mutated amino acid causes dwarfism by preventing an interaction needed for its degradation. This novel mutation confers nondeleterious dwarf phenotypes when transferred to Arabidopsis (Arabidopsis thaliana) and oilseed rape (Brassica napus), indicating its potential usefulness in other crop species.
Water Stress Deforms Tracheids Peripheral to the Leaf Vein of a Tropical Conifer
Authors: Brodribb Tim J. , Holbrook N. Michele
Published: February 2005

Just as a soggy paper straw is prone to yielding under the applied suction of a thirsty drinker, the xylem tracheids in leaves seem prone to collapse as water potential declines, impeding their function. Here we describe the collapse, under tension, of lignified cells peripheral to the leaf vein of a broad-leaved rainforest conifer, Podocarpus grayi de Laub. Leaves of Podocarpus are characterized by an array of cylindrical tracheids aligned perpendicular to the leaf vein, apparently involved in the distribution of water radially through the mesophyll. During leaf desiccation the majority of these tracheids collapsed from circular to flat over the water potential range −1.5 to −2.8 MPa. An increase in the percentage of tracheids collapsed during imposed water stress was mirrored by declining leaf hydraulic conductivity (K  leaf), implying a direct effect on water transport efficiency. Stomata responded to water stress by closing at −2.0 MPa when 45% of cells were collapsed and K  leaf had declined by 25%. This was still substantially before the initial indications of cavitation-induced loss of hydraulic conductance in the leaf vein, at −3 MPa. Plants droughted until 49% of tracheids had collapsed were found to fully recover tracheid shape and leaf function 1 week after rewatering. A simple mechanical model of tracheid collapse, derived from the theoretical buckling pressure for pipes, accurately predicted the collapse dynamics observed in P. grayi, substantiating estimates of cell wall elasticity and measured leaf water potential. The possible adaptive advantages of collapsible vascular tissue are discussed.
Patterns and determinants of shorebird species richness in the circumpolar Arctic
Authors: Henningsson Sara S. , Alerstam Thomas
Published: February 2005

Aim The intention with this study was first to investigate and describe the broad‐scale geographical patterns of species richness of breeding shorebirds (Charadriiformes; families: Charadriidae, Scolopacidae and Haematopodidae) throughout the arctic tundra biome. Secondly, after compensating for the positive relationship between net primary productivity (NPP) and species richness, the relative importance of additional ecological and historical variables for species richness was investigated. The main variables considered are NPP, length of snow‐ and ice‐free season, accessibility of regions depending on migratory flyway systems, tundra area at Pleistocene (120 and 20–18 kabp) and Holocene (8 kabp) times, and tundra area at present.

Methods Information on shorebird species breeding distributions was compiled from distribution atlases and species accounts. The breeding distributions of shorebirds with ranges partly or completely in the Arctic (a total of 50 species) were mapped in ArcView 3.2 to create a raster grid layer of shorebird species richness at a 1° latitude × longitude resolution. The total and mean species richness value was calculated per each 10° of longitude sector of the Arctic. The relationships between species richness and the different climatic and environmental variables were analysed on the basis of this sector‐wise division of the arctic tundra. The influence of each variable on species richness was investigated using univariate and multivariate analyses (multivariate linear regression and general linear model).

Results We found that patterns of breeding shorebird species richness in the Arctic tundra biome are to a large degree determined by the NPP, the length of the snow‐ or ice‐free season, the diversity of migratory flyways, as well as the historical extent of tundra habitat area during the maximum cooling of the last glacial period. Essentially, two main regions are distinguishable in the circumpolar Arctic regarding shorebird community richness. These are a species‐rich Beringia‐centred region and a species‐poor Atlantic‐centred region.

Main conclusions The underlying explanations to these major trends may primarily be attributed to factors that operate at present through accessibility of areas from contemporary migration flyways, as well as processes that operated in the past during and after the last glacial cycle. The most prominent influence on the shorebird diversity was found for NPP in combination with the diversity of migratory flyways. These flyways provide the links between breeding and wintering resources, often separated by huge distances, and the geographical and ecological conditions associated with the shorebirds’ migration seem to be of particular importance for their breeding diversity in different sectors of circumpolar tundra.
A lily pollen ASR protein localizes to both cytoplasm and nuclei requiring a nuclear localization signal
Authors: Wang Huei‐Jing , Hsu Chia‐Mei , Jauh Guang Yuh , Wang Co‐Shine
Published: February 2005

LLA23, an abscisic acid‐, stress‐ and ripening‐induced (ASR) protein, was isolated previously from lily (Lilium longiflorum) pollen. Close examination of the C‐terminus of this ASR protein revealed the presence of basic regions reminiscent of a nuclear localization signal (NLS). Fluorescence microscopy studies using green fluorescent protein (GFP) fusion proteins indicated that the bipartite NLS in LLA23 exhibited nuclear localization properties. Accordingly, mutations in the NLS motifs of LLA23 defined two regions, either of which was necessary for partial nuclear targeting and both of which were required for complete nuclear localization. In addition, oligonucleotide‐directed mutagenesis identified lysine residues within the NLS necessary for nuclear localization. Immunogold localization confirmed that the protein was located to both the cytoplasm and nucleus of generative and vegetative cells of pollen grains; the generative nuclei showed the highest number of LLA23 labelling. The possible function of ASR proteins in both the cytoplasm and nuclei of pollen grains is discussed.
Effects of water stress and nocturnal temperature on carbon allocation in the perennial grass, Leymus chinensis
Authors: Xu Zhen‐Zhu , Zhou Guang‐Sheng
Published: February 2005

Water deficit and high temperature often occur simultaneously, but their effects on plants are usually investigated separately. The aim of this study was to test how interactions between water stress and nocturnal warming affect carbon allocation in the perennial grass, Leymus chinensis. Plant biomass, dry mass allocation, 14C partitioning and carbon isotope composition (δ13C) were measured. Severe and extreme water stress during nocturnal warming decreased the allocation of dry mass and 14C partitioning below ground to the roots, but moderate water stress significantly increased the below‐ground allocation of dry mass and 14C, especially at the lower night temperature. The δ13C values were more positive at day/night temperatures of 30/20°C than at 30/25°C, and greater in the roots than in the leaves. By plotting the δ13C values of the leaves against the δ13C values of the roots, the slopes of regressions were steeper at low than at high night temperature, also indicating that nocturnal warming reduces carbon allocation below ground to the roots. The results suggest that nocturnal warming may weaken acclimation during water stress in this species by regulating carbon allocation between source and sink organs.
Enhanced symbiotic seed germination of Cypripedium macranthos var. rebunense following inoculation after cold treatment
Authors: Shimura Hanako , Koda Yasunori
Published: February 2005

Cypripedium macranthos var. rebunense is a well‐known wild orchid in Japan, and is considered to be a symbol for rare plant conservation. A fungus isolated from roots of C. macranthos var. rebunense induced symbiotic germination of the species in vitro. Cold treatment of the seeds at 4°C prior to fungal inoculation was required for the symbiotic germination. Changing the timing of inoculation of the fungus to the seeds greatly improved germination frequency. Maximum germination was attained after seeds were inoculated just after the cold treatment for 12 weeks, and approximately 20% of the seeds developed into protocorms more than 1 mm long. These results suggest that fungal inoculation takes place at the beginning of spring in nature, and the tough impervious seed coat may preserve the seed from the infection during autumn and winter seasons. The lengthy culture period of more than 16 weeks at 20°C on the same medium with the fungus caused gradual browning and rot of the protocorms. By elimination of the fungus with a fungicide and by transfer to a nutrient rich medium, approximately 20% of the protocorms developed into healthy plantlets. The methods obtained here appear to be applicable to symbiotic germination of many other threatened Cypripedium spp.