bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of the activity of poly (ADP‐ribose) polymerase reduces heart ischaemia/reperfusion injury via suppressing JNK‐mediated AIF translocation
Authors: Song Zhao‐Feng , Ji Xiao‐Ping , Li Xiao‐Xing , Wang Sheng‐Jun , Wang Shu‐Hua , Yun‐Zhang
Published: August 2008

Poly (ADP‐ribose) polymerase (PARP) has been proposed to play an important role in the pathogenesis of heart ischaemia/reperfusion (I/R) injury. However, the mechanisms of PARP‐mediated heart I/R injury in vivo are still not thoroughly understood. Therefore, in this study, we investigate the effect of PARP inhibition on heart I/R injury and try to elucidate the underlying mechanisms. Studies were performed with I/R rats' hearts in vivo. Ischaemia followed by reperfusion caused a significant increase in Poly (ADP‐ribose) (PAR), c‐Jun NH2‐terminal kinase (JNK) and apoptosis‐inducing factor (AIF) activity. Administration of 3,4‐dihydro‐5‐[4‐(1‐piperidinyl)butoxy]‐1(2H)‐isoquinolinone (DPQ), an inhibitor of PARP, decreased myocardial infarction size from 61.11±7.46%[0] to 38.83±5.67% (P<0.05) and cells apoptosis from 35±5.3% to 20±4.1% (P<0.05) and simultaneously improved the cardiac function. Western blot analysis showed that administration of DPQ reduced the activation of JNK and attenuated mitochondrial‐nuclear translocation of AIF. Additionally, administration of SP600125, an inhibitor of JNK, attenuated mitochondrial‐nuclear translocation of AIF. The results of the present study demonstrated that the inhibition of PARP was able to reduce heart I/R injury in vivo. Our results also suggested that JNK may be downstream of PARP activation and be required for PARP‐mediated AIF translocation. Inhibition of the activity of PARP may reduce heart I/R injury via suppressing AIF translocation mediated by JNK.
Internalization of cystatin C in human cell lines
Authors: Ekström Ulf , Wallin Hanna , Lorenzo Julia , Holmqvist Bo , Abrahamson Magnus , Avilés Francesc X.
Published: August 2008

Altered protease activity is considered important for tumour invasion and metastasis, processes in which the cysteine proteases cathepsin B and L are involved. Their natural inhibitor cystatin C is a secreted protein, suggesting that it functions to control extracellular protease activity. Because cystatins added to cell cultures can inhibit polio, herpes simplex and coronavirus replication, which are intracellular processes, the internalization and intracellular regulation of cysteine proteases by cystatin C should be considered. The extension, mechanism and biological importance of this hypothetical process are unknown. We investigated whether internalization of cystatin C occurs in a set of human cell lines. Demonstrated by flow cytometry and confocal microscopy, A‐431, MCF‐7, MDA‐MB‐453, MDA‐MB‐468 and Capan‐1 cells internalized fluorophore‐conjugated cystatin C when exposed to physiological concentrations (1 μm). During cystatin C incubation, intracellular cystatin C increased after 5 min and accumulated for at least 6 h, reaching four to six times the baseline level. Western blotting showed that the internalized inhibitor was not degraded. It was functionally intact and extracts of cells exposed to cystatin C showed a higher capacity to inhibit papain and cathepsin B than control cells (decrease in enzyme activity of 34% and 37%, respectively). The uptake of labelled cystatin C was inhibited by unlabelled inhibitor, suggesting a specific pathway for the internalization. We conclude that the cysteine protease inhibitor cystatin C is internalized in significant quantities in various cancer cell lines. This is a potentially important physiological phenomenon not previously described for this group of inhibitors.
Crystal and solution structure, stability and post‐translational modifications of collapsin response mediator protein 2
Authors: Majava Viivi , Löytynoja Noora , Chen Wei‐Qiang , Lubec Gert , Kursula Petri
Published: August 2008

The collapsin response mediator protein 2 (CRMP‐2) is a central molecule regulating axonal growth cone guidance. It interacts with the cytoskeleton and mediates signals related to myelin‐induced axonal growth inhibition. CRMP‐2 has also been characterized as a constituent of neurofibrillary tangles in Alzheimer’s disease. CD spectroscopy and thermal stability assays using the Thermofluor method indicated that Ca2+ and Mg2+ affect the stability of CRMP‐2 and prevent the formation of β‐aggregates upon heating. Gel filtration showed that the presence of Ca2+ or Mg2+ promoted the formation of CRMP‐2 homotetramers, and this was further proven by small‐angle X‐ray scattering experiments, where a 3D solution structure for CRMP‐2 was obtained. Previously, we described a crystal structure of human CRMP‐2 complexed with calcium. In the present study, we determined the structure of CRMP‐2 in the absence of calcium at 1.9 Å resolution. When Ca2+ was omitted, crystals could only be grown in the presence of Mg2+ ions. By a proteomic approach, we further identified a number of post‐translational modifications in CRMP‐2 from rat brain hippocampus and mapped them onto the crystal structure.
The ycaC‐related protein from the amphioxus Branchiostoma belcheri (BbycaCR) interacts with creatine kinase
Authors: Jiang Shengjuan , Sun Xuemei , Zhang Shicui
Published: August 2008

The ycaC‐related gene, ycaCR, is uncharacterized, and has no assigned function to date. Here we clearly showed that the ycaC‐related gene from the amphioxus Branchiostoma belcheri, BbycaCR, coded for a novel member of the isochorismatase superfamily, which is mainly localized in the mitochondrial fraction. Both pull‐down and reverse pull‐down analyses revealed that BbycaCR was able to interact with creatine kinase, an enzyme involved in energy transduction, in addition to binding to native ycaCR, forming a homopolymer. Surprisingly, neither isochorismatase, nicotinamidase nor N‐carbamoylsarcosine amidohydrolase activity was detected for BbycaCR, although it possessed the putative catalytic triad of Asp19, Arg(Lys)84 and Cys118 that is found in ycaC proteins. Both tissue section in situ hybridization and immunohistochemistry showed that BbycaCR was ubiquitously expressed in amphioxus, although at different expression levels, suggesting that BbycaCR plays a conserved fundamental cellular role in amphioxus. It is proposed that BbycaCR may be indirectly involved in energy transduction.
Importance of tyrosine residues of Bacillus stearothermophilus serine hydroxymethyltransferase in cofactor binding and l‐allo‐Thr cleavage
Authors: Bhavani B. S. , Rajaram V. , Bisht Shveta , Kaul Purnima , Prakash V. , Murthy M. R. N. , Appaji Rao N. , Savithri H. S.
Published: August 2008

Serine hydroxymethyltransferase (SHMT) from Bacillus stearothermophilus (bsSHMT) is a pyridoxal 5′‐phosphate‐dependent enzyme that catalyses the conversion of l‐serine and tetrahydrofolate to glycine and 5,10‐methylene tetrahydrofolate. In addition, the enzyme catalyses the tetrahydrofolate‐independent cleavage of 3‐hydroxy amino acids and transamination. In this article, we have examined the mechanism of the tetrahydrofolate‐independent cleavage of 3‐hydroxy amino acids by SHMT. The three‐dimensional structure and biochemical properties of Y51F and Y61A bsSHMTs and their complexes with substrates, especially l‐allo‐Thr, show that the cleavage of 3‐hydroxy amino acids could proceed via Cα proton abstraction rather than hydroxyl proton removal. Both mutations result in a complete loss of tetrahydrofolate‐dependent and tetrahydrofolate‐independent activities. The mutation of Y51 to F strongly affects the binding of pyridoxal 5′‐phosphate, possibly as a consequence of a change in the orientation of the phenyl ring in Y51F bsSHMT. The mutant enzyme could be completely reconstituted with pyridoxal 5′‐phosphate. However, there was an alteration in the λmax value of the internal aldimine (396 nm), a decrease in the rate of reduction with NaCNBH3 and a loss of the intermediate in the interaction with methoxyamine (MA). The mutation of Y61 to A results in the loss of interaction with Cα and Cβ of the substrates. X‐Ray structure and visible CD studies show that the mutant is capable of forming an external aldimine. However, the formation of the quinonoid intermediate is hindered. It is suggested that Y61 is involved in the abstraction of the Cα proton from 3‐hydroxy amino acids. A new mechanism for the cleavage of 3‐hydroxy amino acids via Cα proton abstraction by SHMT is proposed.
Structural and functional characterization of human Iba proteins
Authors: Schulze Jörg O. , Quedenau Claudia , Roske Yvette , Adam Thomas , Schüler Herwig , Behlke Joachim , Turnbull Andrew P. , Sievert Volker , Scheich Christoph , Mueller Uwe , Heinemann Udo , Büssow Konrad
Published: August 2008

Iba2 is a homolog of ionized calcium‐binding adapter molecule 1 (Iba1), a 17‐kDa protein that binds and cross‐links filamentous actin (F‐actin) and localizes to membrane ruffles and phagocytic cups. Here, we present the crystal structure of human Iba2 and its homodimerization properties, F‐actin cross‐linking activity, cellular localization and recruitment upon bacterial invasion in comparison with Iba1. The Iba2 structure comprises two central EF‐hand motifs lacking bound Ca2+. Iba2 crystallized as a homodimer stabilized by a disulfide bridge and zinc ions. Analytical ultracentrifugation revealed a different mode of dimerization under reducing conditions that was independent of Ca2+. Furthermore, no binding of Ca2+ up to 0.1 mm was detected by equilibrium dialysis. Correspondingly, Iba EF‐hand motifs lack residues essential for strong Ca2+ coordination. Sedimentation experiments and microscopy detected pronounced, indistinguishable F‐actin binding and cross‐linking activity of Iba1 and Iba2 with induction of F‐actin bundles. Fluorescent Iba fusion proteins were expressed in HeLa cells and co‐localized with F‐actin. Iba1 was recruited into cellular projections to a larger extent than Iba2. Additionally, we studied Iba recruitment in a Shigella invasion model that induces cytoskeletal rearrangements. Both proteins were recruited into the bacterial invasion zone and Iba1 was again concentrated slightly higher in the cellular extensions.
Hemitoxin, the first potassium channel toxin from the venom of the Iranian scorpionHemiscorpius lepturus
Authors: Srairi‐Abid Najet , Shahbazzadeh Delavar , Chatti Imen , Mlayah‐Bellalouna Saoussen , Mejdoub Hafedh , Borchani Lamia , Benkhalifa Rym , Akbari Abolfazl , El Ayeb Mohamed
Published: August 2008

Hemitoxin (HTX) is a new K+channel blocker isolated from the venom of the Iranian scorpionHemiscorpius lepturus. It represents only 0.1% of the venom proteins, and displaces [125I]α‐dendrotoxin from its site on rat brain synaptosomes with an IC50value of 16 nm. The amino acid sequence of HTX shows that it is a 35‐mer basic peptide with eight cysteine residues, sharing 29–69% sequence identity with other K+channel toxins, especially with those of the αKTX6 family. A homology‐based molecular model generated for HTX shows the characteristic α/β‐scaffold of scorpion toxins. The pairing of its disulfide bridges, deduced from MS of trypsin‐digested peptide, is similar to that of classical four disulfide bridged scorpion toxins (Cys1–Cys5, Cys2–Cys6, Cys3–Cys7 and Cys4–Cys8). Although it shows the highest sequence similarity with maurotoxin, HTX displays different affinities for Kv1 channel subtypes. It blocks rat Kv1.1, Kv1.2 and Kv1.3 channels expressed inXenopusoocytes with IC50values of 13, 16 and 2 nm, respectively. As previous studies have shown the critical role played by the β‐sheet in Kv1.3 blockers, we suggest that Arg231 is also important for Kv1.3 versus Kv1.2 HTX positive discrimination. This article gives information on the structure–function relationships of Kv1.2 and Kv1.3 inhibitors targeting developing peptidic inhibitors for the rational design of new toxins targeting given K+channels with high selectivity.
Cholinesterase‐Inhibiting and Genotoxic Effects of Acute Carbofuran Intoxication in Man: A Case Report
Authors: Zeljezic Davor , Vrdoljak Ana Lucic , Kopjar Nevenka , Radic Bozica , Milkovic Kraus Sanja
Published: August 2008

Abstract: Carbofuran belongs to the group of N‐methylcarbamate insecticides used for the control of soil‐dwelling and foliar‐feeding insects in various crops; its consumption totals approximately 20,000 tonnes per year. Although the neurological effects on human beings have been well documented, little is known on its impact on the genome. A 38‐year‐old, healthy male worker employed in a carbofuran production facility accidentally inhaled the dust of the active ingredient carbofuran. Thirty minutes later, he experienced weakness, fatigue, perspiration, breathing difficulties, cephalalgia, disorientation, abdominal pain and vomiting. Blood samples were taken to measure cholinesterase activity, and to perform the alkaline comet assay and micronucleus assay combined with pancentromeric probes. Analyses were repeated 72 hr after intoxication and compared with the results obtained from regular monitoring conducted 10 days prior to the accident. Cholinesterase activity showed the highest correlation with the number of apoptotic cells, comet assay tail length, and number of long‐tailed nuclei, suggesting that these are the genomic end‐points primarily affected by carbofuran intake. Only a weak correlation was detected for the total number of micronuclei, centromere‐containing micronuclei and nuclear buds. Since those end‐points increased significantly 72 hr after the accident, they could be considered as late biomarkers of the effects of carbofuran intoxication. The results of this report suggest that, in the interests of higher standards in risk assessment and health hazard protection, periodical medical examination of carbamate‐exposed populations should include genotoxicity testing in addition to the assessment of cholinesterase activity.
Sedative‐Hypnotic Medication Exposures and Poisonings in Izmir, Turkey*
Authors: Oray Nese Colak , Hocaoglu Nil , Oray Deniz , Demir Omer , Atilla Ridvan , Tuncok Yesim
Published: August 2008

Abstract:  The aim of this study was to analyse intoxications concerning sedative‐hypnotic medication patients admitted to the Department of Emergency Medicine in Dokuz Eylul University Hospital (EMDEU) between 1993 and 2005. Demographics of the patients, characteristics of sedative‐hypnotic exposures, performed treatment attempts and outcome of the poisoned patients were recorded on standard data forms that were later entered into a computerized database programme. Related to the sedative‐hypnotic exposures, 686 poisoning cases were admitted to the EMDEU. Mean age was 10.8 ± 6.5 years among the paediatric age group (<17 years old, 169, 24.6%) and 30.3 ± 12.8 years among the adult group (>17 years old, 509, 74.2%). The most common sedative‐hypnotic agents were benzodiazepines (286, 35.8%), alprazolam accounted for 41.6% of them (119). Most of the patients admitted to EMDEU were asymptomatic (61.7%). Observation alone was recommended in 53.9% of EMDEU cases. Although prescription of benzodiazepines is restricted, benzodiazepine was the most common cause of sedative‐hypnotic medication exposures. As only a minority of patients (3%) had clinically serious signs and symptoms, most of the overdoses might be under toxic levels or the decontamination methods might be efficient. In this study, the clinical outcome of the patients is relatively better than previous results described in literature.
Antinociceptive and Adverse Effects of µ‐ and κ‐Opioid Receptor Agonists: A Comparison of Morphine and U50488‐H
Authors: Gallantine Elizabeth L. , Meert Theo F.
Published: August 2008

Abstract: Although µ‐opioids such as morphine are undoubtedly effective in the treatment of acute and postoperative pain, κ‐opioids are of interest for the modulation of visceral pain. In the present study, we compared a κ‐opioid agonist (U50488‐H; 0.63–40 mg/kg) with a µ‐opioid agonist (morphine; 0.63–40 mg/kg) in different pain models (tail withdrawal, writhing, formalin and plantar test) to represent acute, peritoneovisceral and inflammatory pain states in rats. The effects of the respective receptor agonists on gastrointestinal motility, muscle rigidity and abuse liability were also studied in appropriate animal models (charcoal, castor oil, rotarod and drug discrimination learning). Morphine was highly efficacious in all the nociceptive models employed, but also elicited a potent inhibition of gastric motility, caused severe muscle rigidity and locomotor disturbances and displayed a potential for abuse liability at the higher doses tested (≥10 mg/kg morphine). In contrast, U50488‐H was inactive in the tail withdrawal test, but was more effective in visceral and inflammatory pain settings. Although U50488‐H did not elicit any gastrointestinal inhibition, a loss of muscle tone following administration of the compound led to detrimental effects on rotarod performance. The findings presented here indicate that κ‐opioids possess antinociceptive efficacy in visceral and inflammatory pain settings, but their administration can lead to a loss of muscle tone. In contrast, µ‐opioids are highly active as analgesics against a range of nociceptive stimuli, but also concomitantly elicit strongly adverse effects.
Influence of Mirtazapine on the Hypotensive Activity of Enalapril and Propranolol in Spontaneously Hypertensive Rats
Authors: Andrzejczak Dariusz , Kocon Katarzyna , Zięba Remigiusz
Published: August 2008

Abstract: Mirtazapine is a noradrenergic and specific serotonergic antidepressant. The influence of the drug on the cardiovascular system has not been definitely determined. Therefore, we made an attempt to evaluate the influence of chronic administration of mirtazapine on the hypotensive action of a single administered dose of propranolol and enalapril in spontaneously hypertensive rats. The animals were divided into eight experimental groups. Mirtazapine (5 and 10 mg/kg) was administered intraperitoneally for 14 days. Twenty‐four hours after the last administration of the drug, the rats received a single intraperitoneal dose of hypotensive drugs (propranolol 5 mg/kg or enalapril 10 mg/kg) or 1% solution of methylcellulose. Mirtazapine administered chronically did not affect the hypotensive effect of a single dose of propranolol or enalapril in spontaneously hypertensive rats. It seems that mirtazapine could be a useful drug in patients with depression accompanied by hypertension.
Shifting Common Spaces of Plant Genetic Resources in the International Regulation of Property
Authors: Roa‐Rodríguez Carolina , Van Dooren Thom
Published: August 2008

The appellative “common heritage of mankind” is often used as a description of the property domain that governed plant genetic resources (PGR) at an international level up until the end of the twentieth century. However, the concept is rarely elaborated on. In this article we explore the origins of common property in PGR and the shifting content and shape of the genetic commons over the past several decades.

Using the theoretical framework of diverse common property regimes developed by Peter Drahos, we chart the way in which the emergence and interaction of various international regulatory regimes related to PGR reshape common property spaces, rights and obligations.

We argue that these international agreements do not regulate a single property domain in isolation, but rather modify the content and boundaries of the complex set of property domains that apply to PGR: private, state, common and public. More than a theoretical conundrum, we show that any realistic appraisal of the implementation of the international regulatory regimes in relation to PGR must acknowledge the conflicting and complex dynamics of these interrelated property domains, as well as the way in which they are being put into place on the ground.
Scope of Process Patents in Farm Animal Breeding
Authors: Tvedt Morten Walløe , Finckenhagen Magnus
Published: August 2008

The number of process patent applications concerning farm animal breeding is growing rapidly. Patent law is general in form and is seldom adapted to specific areas of innovation. It was initially created for the purpose of granting exclusive rights to technical inventions, and it was taken for granted that higher animals, food production and pharmaceuticals were too important for mankind to be included under exclusive private rights. Today, with patent law increasingly used in the animal sector, the question arises: how will the law apply to this particular field of innovation? The degree of legal uncertainty is particularly high because it is not clear how the courts of various countries will apply the general law to this particular field. Patent law has the potential to alter the existing legal conditions for competition and investments in the field of animal breeding, and thus merits greater attention among policy‐makers, animal breeders and farmers.
R v Millis reconsidered: binding contracts and bigamous marriages
Authors: Probert Rebecca
Published: August 2008

The 1844 decision of the House of Lords in R v Millis – which apparently held that the presence of an episcopally ordained minister had been necessary to create a valid marriage even before legislation was introduced to regulate the formation of marriage – has universally been regarded as erroneous by generations of scholars. This paper shows that the outcome of the case was in fact correct, even though the reasoning of all but one of the judges was flawed. It explains why the case has been misunderstood, and why the misunderstandings it demonstrated have never been corrected.
An introduction to magma dynamics
Authors: Zellmer Georg F. , Annen Catherine
Published: August 2008

A variety of methods have been employed to decipher magmatic systems, including geophysical, petrological, textural and geochemical approaches, and these elucidate a large variety of characteristics of different plumbing systems and magmatic differentiation processes. A common theme to the papers presented in this book is the observation of transport of small volume magma batches with a relatively high frequency, as opposed to less frequent transport of larger magma volumes that would require storage in large crustal reservoirs for long periods of time. The implications of this observation are discussed in the context of a possible tectonic control on crustal magma dynamics.
Long-term geochemical variability of the Late Cretaceous Tuolumne Intrusive Suite, central Sierra Nevada, California
Authors: Gray Walt , Glazner Allen F. , Coleman Drew S. , Bartley John M.
Published: August 2008

This study investigates the internal anatomy and petrogenesis of the Tuolumne Intrusive Suite (TIS), which comprises metaluminous, high-potassium, calc-alkaline granitoids typical of the Sierra Nevada batholith. Although the TIS has often been cited as an example of a large magma chamber that cooled and fractionated from the margins inward, its geochemistry is inconsistent with closed-system fractionation. Most major elements are highly correlated with SiO2, but the scattered nature of trace elements and variations of initial Sr and Nd isotopic ratios indicate that fractional crystallization is not the predominant process responsible for its chemical evolution. Isotopic data suggest mixing between melts of mantle-like rocks and a granitic melt similar in composition to the highest-silica TIS unit. Monte Carlo models of magma mixing confirm that such processes can reproduce the observed variations in major elements, trace elements and isotopic ratios. Thermobarometry suggests emplacement at depths near 6 km and crystallization temperatures ranging from 660 to 750 °C. Feldspars, hornblende, biotite and magnetite exhibit evidence of extensive low-temperature subsolidus exsolution. The TIS as a whole trends toward more evolved isotopic compositions and younger U–Pb zircon ages passing inward. This pattern indicates a general increase in the proportion of felsic, crustally derived melt in the mixing process, which may have resulted from net accumulation of heat added to the lower crust by intrusion of mantle-derived mafic magma. However, the bulk geochemical and isotopic compositions of the equigranular Half Dome Granodiorite, the porphyritic Half Dome Granodiorite and the Cathedral Peak Granodiorite overlap one another and the contacts between them are commonly gradational. We interpret these map units to represent a single petrological continuum rather than distinct intrusive phases. The textural differences that define the units probably reflect thermal evolution of the system rather than distinct intrusive events.
Construction, solidification and internal differentiation of a large felsic arc pluton: Cathedral Peak granodiorite, Sierra Nevada Batholith
Authors: Burgess S. D. , Miller J. S.
Published: August 2008

The Tuolumne Batholith (TB), Sierra Nevada Batholith (USA), is an archetypal large, zoned arc intrusion (
c
. 1200 km
2
). Previous work proposed that compositional zonation observed in the TB was produced
in-situ
by inward differentiation of a large magma chamber and/or large-scale, intrachamber magma mixing. Recent geochronology shows that the TB was intruded over 8–9 Ma, making single pulse fractionation or mixing in a magma chamber of TB dimensions unlikely. We examine processes responsible for compositional variation in the Cathedral Peak Granodiorite, which is the largest mapped unit of the TB. New field, geochemical and geochronological work along a roughly contact-perpendicular 5 km transect indicates: (1) magmatic foliation is steeply-dipping (>60°); (2) field evidence for repeated separation of crystals from melt and local magma mixing is observed; (3) U–Pb zircon ages at opposing ends of the transect are indistinguishable within error (
c
. 87.5 Ma); (4) bulk composition varies only modestly but trace elements show variable degrees of scatter; (5) εNd(t) and
87
Sr/
86
Sr(i) have small variation compared with that in the whole TB. Geochemical and isotopic data are compatible with fractionation of major silicates and accessory minerals. However, the geochemical spatial variation, minor isotopic variation and field evidence suggest that fractionation was highly disorganized and also involved mixing with new input magma and remobilization of crystal mush as the pluton solidified. Our observations are consistent with the construction of a large and dynamic magma system within the last
c
. 1 Ma of TB growth.
Snake River Plain – Yellowstone silicic volcanism: implications for magma genesis and magma fluxes
Authors: Leeman William P. , Annen Catherine , Dufek Josef
Published: August 2008

The origin of large-volume, high-temperature silicic volcanism associated with onset of the Snake River Plain – Yellowstone (SRPY) hotspot track is addressed based on evolution of the well-characterized Miocene Bruneau–Jarbidge (BJ) eruptive centre. Although O–Sr–Pb isotopic and bulk compositions of BJ rhyolites exhibit strong crustal affinity, including strong
18
O-depletion, Nd isotopic data preclude wholesale melting of ancient basement rocks and implicate involvement of a juvenile component – possibly derived from contemporaneous basaltic magmas. Several lines of evidence, including limits on
18
O-depletion of the rhyolite source rocks due to influx of meteoric/hydrothermal fluids, constrain rhyolite generation to depths shallower than mid-upper crust (<20 km depth). For crustal melting driven by basaltic intrusions, sustenance of temperatures exceeding 900 °C at such depths over the life of the BJ eruptive centre requires incremental intrusion of approximately 16 km of basalt into the crust. This minimum basaltic flux (
c
. 4 mm year
−1
) is about one-tenth that at Kilauea. Nevertheless, emplacement of such volumes of magma in the crust creates a serious room problem, requiring that the crust must undergo significant extensional deformation – seemingly exceeding present estimates of extensional strain for the SRPY province.
Uniform processes of melt differentiation in the central Izu Bonin volcanic arc (NW Pacific)
Authors: Straub Susanne M.
Published: August 2008

The intra-oceanic Izu Bonin arc (NW Pacific) has produced a bimodal spectrum of melts with maxima in the basaltic andesitic (
c
. 53–54 wt% SiO
2
) and rhyolitic range (
c
. 70–72 wt% SiO
2
) since arc inception
c
. 48–49 million years ago. Composition of phenocrysts and accessory minerals from 21 contemporaneous fallout tephras from ODP Site 782A confirm the bimodality and uniformity of the erupted melts. The basaltic andesite melts equilibrated with calcic plagioclase (
c
. An
70–95
), high-Mg# clino- and orthopyroxene and low-Ti titanomagnetite. Dacitic and rhyolitic melts crystallized sodic plagioclase (
c
. An
40–60
), low-Mg# clino- and orthopyroxene, apatite, Ti-rich titanomagnetite in addition to occasional ilmenite and amphibole. The Izu melts are inferred to crystallize at oxygen fugacities between
c
. 0 to +2.5 log
10
units relative to FMQ, at temperatures between
c
. 775° and 1100 °C and at pressures between
c
. 300 and
c
. 1100 MPa, corresponding to
c
. 5–35 km lithospheric depth. The compositional uniformity of the tephra layers, which are spaced on average 230 ± 380 ka apart, suggest uniform processes of differentiation since at least
c
. 42 Ma ago. The tephra record shows no indication of periodic or progressive crustal growth that might correlate with the alternate periods of arc formation, arc rifting or backarc spreading, or would suggest an increasingly efficient ‘crustal filter’ with time. The tephra data tentatively conform to a model where crust grows steadily through intrusions of mafic and evolved melt body batches whereby buoyancy controls the level of solidification. While the tephra compositions demonstrate the uniformity of the processes of melt formation and differentiation through time, the data do not permit the differentiation processes themselves to be constrained. These may comprise fractional crystallization, crustal fusion, fusion of non-peridotitic sub-crustal lithologies, or any combination of these processes.
Some first-order observations on magma transfer from mantle wedge to upper crust at volcanic arcs
Authors: Zellmer Georg F.
Published: August 2008

The viscosity of lavas erupted at volcanic arcs varies over orders of magnitude. A comparison of the relative abundance of viscous lava dome eruptions indicates that the average viscosity of arc lavas also varies considerably between arcs. It is shown that, for continental or transitional arcs with little within-arc crustal deformation and without underlying slab windows or tears, average lava viscosity is anticorrelated with average surface heat flux. The latter may be influenced by crustal thickness and crustal magma throughput. To constrain the relative contributions of these parameters, variations of average lava viscosity with average crustal thickness and plate convergence rate are assessed. While crustal thickness appears to have little effect on average lava viscosity, a good anticorrelation exists between average lava viscosity and plate convergence rate, with the exception of two arcs that show significant intra-arc crustal deformation. If plate convergence rate is a good proxy of the rate of melt generation within the mantle wedge, these first-order observations indicate that, where the rate of mantle melting is high, crustal magma throughput is rapid and efficient, resulting in low-viscosity melts migrating through a hot overriding crust; in contrast, where the rate of mantle melting is low, crustal magma transfer is slow and inefficient, resulting in high-viscosity melts that may frequently stall within a cool overriding crust prior to eruption. Uranium series geochemical evidence from dome lavas is presented and lends support to this interpretation. Finally, some explanations are offered for the observed average viscosity variations of arcs with underlying slab windows or tears and/or significant intra-arc crustal deformation.
A rigorous tool for evaluating the importance of viscous dissipation in sill formation: it's in the tip
Authors: Bunger Andrew P.
Published: August 2008

Crustal magma transport is typically described using a complex, non-linear model associated with fluid-driven fracturing, and therefore fundamentally sound modelling forms the basis for interpretation of magmatic intrusions. One of the most basic considerations is that magma-driven sills can be broadly categorized based on the energy dissipation mechanism that is predominant during intrusion growth. In cases where either viscous flow or overcoming fracture toughness strongly dominates fracture behaviour, it is typical to speak of viscosity-dominated or toughness-dominated regimes, each of which defines a class of fracture propagation with significant implications for modelling. This paper presents a straightforward and geometry-independent means for local determination of the expected propagation regime based on an experimentally verified mathematical analysis of the multi-scale, coupled mechanics that govern the near-tip region. The propagation regime is then related directly to the ratio between a characteristic length associated with the near-tip physics compared with the size of the fracture/sill. Sill growth is shown to be expected in or near the viscosity-dominated regime and hence modelling generally must take into account the complexity of the near-tip region rather than relying solely on the tip behaviour implied by linear elastic fracture, although toughness-dominated mafic intrusions can also be anticipated if fracture toughness increases sufficiently rapidly with the intrusion size.
Dynamics of magma supply to Kīlauea volcano, Hawai‘i: integrating seismic, geodetic and eruption data
Authors: Wright Thomas L. , Klein F. W.
Published: August 2008

We focus on movement of magma beneath Kīlauea from the long summit eruption in 1967–1968 through the first historical sustained eruption on the east rift zone (Mauna Ulu 1969–1974), ending with the occurrence of a magnitude 7.2 earthquake beneath Kīlauea's eastern south flank. Magma from the Hawai‘iian hot spot continuously moves upward to summit storage and drives seaward spreading of Kīlauea's south flank on a 10–12 km deep décollement. Spreading creates dilation in Kīlauea's rift zones and provides room to store magma at depths extending to the décollement surface. During the period of study three types of eruptions – normal (short-lived), episodic and sustained – and three types of intrusions – traditional (summit to rift), inflationary and slow – are classified. Rates of sustained eruption are governed by the geometry of the magmatic plumbing. Swarms of earthquakes beneath the south flank signal increased pressure from magma entering Kīlauea's adjacent rift zone. Magma supply rates are obtained by combining the volume of magma transferred to sites of eruption or intrusion with the volume opened by seaward spreading over the same increment of time. In our interpretation the varying character of eruptions and intrusions requires a gradual increase in magma supply rate throughout the period augmented by incremental increases in spreading rate. The three types of eruptions result from different combinations of magma supply and spreading rate.
Magnetic signatures associated with magma ascent and stagnation at Popocatepetl volcano, Mexico, during 2006
Authors: Pozzo Ana Lillian Martin-Del , Cifuentes Gerardo , González Eduardo , Martinez Alicia , Mendiola Fabiola
Published: August 2008

Monitoring of real-time magnetic signals at Popocatepetl during 2006 has allowed discrimination of magma injection and dome growth. Magnetic signals correlated with seismic, volcanotectonic events and harmonic tremor, as well as number of small emissions, spring water pH, ash components and dome evolution helped define upward magma transport and yield a better understanding of the volcanic plumbing system. Magma ascent occurs mostly in periods of 7±3 days associated with harmonic tremor and decreasing magnetic signals between −1.1 and −15 nT, followed by increasing signals linked to cooling of the domes and increased seismicity over periods of 1 to more than 3 months. The dome clogs the vent after the negative magnetic anomaly–harmonic tremor period associated with magma ascent and forces an explosive crater-reopening explosion. Larger negative changes in the magnetic signals occurred in April (−6 nT), August (−3 to −6 nT) and October to December (−5 to −15 nT), associated with dome formation and growth. Negative magnetic anomalies preceded eruptions by 3 days in 2006.
Understanding crystal populations and their significance through the magma plumbing system
Authors: Jerram Dougal A. , Martin Victoria M.
Published: August 2008

Crystals are rarely composed of a single crystal population that have grown solely from the batch of magma in which they are resident on emplacement, either by eruption or shallow intrusion. Close investigation of the majority of crystal populations reveal that they comprise up to four main components: phenocrysts, crystals co-genetic with their magmatic host; xenocrysts, crystals wholly, or in part, foreign to the magmatic host and magma system; antecrysts, crystals which are recycled one or several times before inclusion in the host magma but have an origin within the magmatic system; and microlites, which represent small co-genetic crystals which nucleate and grow rapidly on decompression and eruption. Textural analysis techniques are employed to quantify key aspects of the crystal population, including crystal shape, crystal size distributions, spatial distribution patterns and textural modification using dihedral angles. Santorini provides a case study of an active volcanic system where a combined textural analysis study has been developed, highlighting how the crystal population is being continuously modified by a series of replenishment and mixing events. Developing textural and microgeochemical techniques provides the next stage in the interrogation of crystal populations, linking textures to isotopic heterogeneities and providing fingerprints of where crystals are sourced and re-cycled.
Evidence for a short-lived stratified magma chamber: petrology of the Z-To5 tephra layer (
c
. 5.8 ka) at Zao volcano, NE Japan
Authors: Ban Masao , Sagawa Hiyori , Miura Kotaro , Hirotani Shiho
Published: August 2008

Volcanic rocks from the Z-To5 tephra layer of Zao volcano, NE Japan, preserve petrological information that reflects the magmatic processes under the volcano. The Z-To5 rocks were formed by the mixing of three magmas that differed in composition and phenocryst assemblage: basalt (1150–1200 °C), with high Mg (Fo

c
. 81

) olivine; basaltic andesite (1020–1100 °C), with Mg-rich orthopyroxene (Mg#=
c
. 78) and clinopyroxene (Mg#=
c
. 78), lower Mg olivine (Mg#=
c
. 78), and calcic (An

c
. 85

) plagioclase; and andesite (900–1000 °C) with Mg-poor orthopyroxene (Mg#=61–66) and clinopyroxene (Mg#=64–68), and An-poor plagioclase. The basaltic magma was formed through fractionation of Fo

c
. 85

olivine from a less differentiated basaltic magma during its fast ascent from the depths. The andesitic magma, which occupied a shallow magma chamber, was heated by underplating of the basaltic magma, resulting in dissolution of some minerals. Subsequently, the basaltic andesite magma was formed by mixing of the basaltic and andesitic magmas in the chamber. Petrological evidence for the rapid growth of phenocrysts in the basaltic andesite magma suggests that the magma residence time was short. The basaltic andesite magma, mixing with a small portion of the andesitic magma, was withdrawn upon eruption. The rates of these processes are inferred to be rapid based on petrological considerations.
Uranium-series isotope and thermal constraints on the rate and depth of silicic magma genesis
Authors: Dosseto A. , Turner S. P. , Sandiford M. , Davidson J.
Published: August 2008

Uranium-series isotopes provide important constraints on the timescale of magma differentiation and this can be used to identify where in the crust and silicic magmas acquire their geochemical characteristics. Timescales of differentiation can be inferred from the observed co-variations of U-series disequilibria with differentiation indexes. When crustal assimilation of secular equilibrium material is involved, inferred timescales will generally decrease. In turn, they will increase if periodical recharge (>20 wt% relative volume) of the magma body occurs. If crustal assimilation and magma recharge occur concurrently, inferred timescales for differentiation can be similar to that of closed system differentiation. We illustrate the approach with data from Mount St Helens which suggest that dacitic compositions are produced in
c
. 2000 years. Combining this with recent evidence for an important role for amphibole fractionation suggests that differentiation of a
c
. 10 km
3
magma body at this volcanic centre occurs at 8–10 km depth in the crust.
Effects of Retroviruses on Host Genome Function
Authors: Jern Patric , Coffin John M.
Published: August 2008

For millions of years, retroviral infections have challenged vertebrates, occasionally leading to germline integration and inheritance as ERVs, genetic parasites whose remnants today constitute some 7% to 8% of the human genome. Although they have had significant evolutionary side effects, it is useful to view ERVs as fossil representatives of retroviruses extant at the time of their insertion into the germline and not as direct players in the evolutionary process itself. Expression of particular ERVs is associated with several positive physiological functions as well as certain diseases, although their roles in human disease as etiological agents, possible contributing factors, or disease markers—well demonstrated in animal models—remain to be established. Here we discuss ERV contributions to host genome structure and function, including their ability to mediate recombination, and physiological effects on the host transcriptome resulting from their integration, expression, and other events.
Convergent Evolution of Alternative Splices at Domain Boundaries of the BK Channel
Authors: Fodor Anthony A. , Aldrich Richard W.
Published: August 2008

Alternative splicing is a widespread mechanism for generating transcript diversity in higher eukaryotic genomes. The alternative splices of the large-conductance calcium-activated potassium (BK) channel have been the subject of a good deal of experimental functional characterization in the Arthropoda, Chordata, and Nematoda phyla. In this review, we examine a list of splices of the BK channel by manual curation of Unigene clusters mapped to mouse, human, chicken, Drosophila, and Caenorhabditis elegans genomes. We find that BK alternative splices do not appear to be conserved across phyla. Despite this lack of conservation, splices occur in both vertebrates and invertebrates at identical regions of the channel at experimentally established domain boundaries. The fact that, across phyla, unique splices occur at experimentally established domain boundaries suggests a prominent role for the convergent evolution of alternative splices that produce functional changes via changes in interdomain communication.
The Cyclodextrin Glycosyltransferase of Paenibacillus pabuli US132 Strain: Molecular Characterization and Overproduction of the Recombinant Enzyme
Authors: Jemli Sonia , Ben Messaoud Ezzedine , Ben Mabrouk Sameh , Bejar Samir
Published: August 2008

The gene encoding the cyclodextrin glycosyltransferase (CGTase) of Paenibacillus pabuli US132, previously described as efficient antistaling agent and good candidate for cyclodextrins production, was cloned, sequenced, and expressed in Escherichia coli. Sequence analysis showed that the mature enzyme (684 amino acids) was preceded by a signal peptide of 34 residues. The enzyme exhibited the highest identity (94%) to the β‐CGTase of Bacillus circulans no. 8. The production of the recombinant CGTase, as active form, was very low (about 1 U/mL) in shake flasks at 37∘C. This production reached 22 U/mL after 22 hours of induction by mainly shifting the postinduction temperature from 37 to 19∘C and using 2TY instead of LB medium. High enzyme production (35 U/mL) was attained after 18 hours of induction in fermentor using the same culture conditions as in shake flask. The recombinant enzyme showed Vmax⁡ and Km values of 253 ± 36 μmol of β‐cyclodextrin/mg/min and 0.36 ± 0.18 g/L, respectively.
Aliskiren
Authors: Brown Morris J.
Published: August 2008

Aliskiren is the first orally active inhibitor of renin to be approved for clinical use as an antihypertensive agent. The development program has established that at the licensed doses of 150 mg and 300 mg, there are dose-related falls in blood pressure comparable to those seen with other major classes of antihypertensive drugs and that these falls are associated with a placebo level of side effects. Aliskiren was found to be effective either as monotherapy or in combination with drugs from the other major classes. As expected, there was a greater benefit from adding aliskiren to natriuretic drugs than to other blockers of the renin system. However, there was also some consistent benefit from dual renin blockade. Aliskiren is likely to be of most value in patients uncontrolled by, or intolerant of, other classes. Rational understanding of the renin system will maximize its value, for instance, by encouraging greater use of natriuretic agents in patients with resistant hypertension to render their hypertension renin dependent. Whether there are cardiovascular benefits other than blood pressure control in blocking the renin system remains to be demonstrated. It is hoped that long-term outcome studies with aliskiren will finally allow this question to be answered.
A Minimal Recursion Semantic Analysis of Locatives
Authors: Jørgensen Fredrik , Lønning Jan Tore
Published: August 2008

The article describes a pilot implementation of a grammar containing different types of locative PPs. In particular, we investigate the distinction between static and directional locatives, and between different types of directional locatives. Locatives may act as modifiers as well as referring expressions depending on the syntactic context. We handle this with a single lexical entry. The implementation is of Norwegian locatives, but English locatives are both discussed and compared to Norwegian locatives. The semantic analysis is based on a proposal by Markus Kracht (2002), and we show how this analysis can be incorporated into Minimal Recursion Semantics (MRS) (Copestake et al. 2005). We discuss how the resulting system may be applied in a transfer-based machine translation system, and how we can map from a shallow MRS representation to a deeper semantic representation.
Constructing Corpora for the Development and Evaluation of Paraphrase Systems
Authors: Cohn Trevor , Callison-Burch Chris , Lapata Mirella
Published: August 2008

Automatic paraphrasing is an important component in many natural language processing tasks. In this article we present a new parallel corpus with paraphrase annotations. We adopt a definition of paraphrase based on word alignments and show that it yields high inter-annotator agreement. As Kappa is suited to nominal data, we employ an alternative agreement statistic which is appropriate for structured alignment tasks. We discuss how the corpus can be usefully employed in evaluating paraphrase systems automatically (e.g., by measuring precision, recall, and F1) and also in developing linguistically rich paraphrase models based on syntactic structure.