Uranium in larval shells as a barometer of molluscan ocean acidification exposure

As the ocean undergoes acidification, marine organisms will become increasingly exposed to reduced pH, yet variability in many coastal settings complicates our ability to accurately estimate pH exposure for those organisms that are difficult to track. Here we present shell-based geochemical proxies that reflect pH exposure from laboratory and field settings in larvae of the mussels Mytilus californianus and M. galloprovincialis. Laboratory-based proxies were generated from shells precipitated at pH 7.51 to 8.04. U/Ca, Sr/Ca, and multielemental signatures represented as principal components varied with pH for both species. Of these, U/Ca was the best predictor of pH and did not vary with larval size, with semidiurnal pH fluctuations, or with oxygen concentration. Field applications of U/Ca were tested with mussel larvae reared in situ at both known and unknown pH conditions. Larval shells precipitated in a region of greater upwelling had higher U/Ca, and these U/Ca values corresponded well with the laboratory-derived U/Ca-pH proxy. Retention of the larval shell after settlement in molluscs allows use of this geochemical proxy to assess ocean acidification effects on marine populations.

The Islamic Crossed-Arch Domes in Cordoba: Geometry and Structural Analysis of the “Capilla de Villaviciosa”

Crossed-arch domes are a singular type of ribbed vaults. Their characteristic feature is that the ribs that form the vault are intertwined, forming polygons or stars, leaving an empty space in the centre. The earliest known vaults of this type are found in the Great Mosque of Córdoba, built ca. 960 a.C. The type spread through Spain, and the north of Africa in the 10th to the 16th Centuries, and was used by Guarini and Vittone in the 17th and 18th Centuries in Italy. However, it was used only in a few buildings. Though the literature about the structural behaviour of ribbed Gothic vaults is extensive, so far no structural analysis of crossed arch domes has been made. The purpose of this work is, first to show the way to attack such an analysis within the frame of Modern Limit Analysis of Masonry Structures (Heyman 1995), and then to apply the approach to study the stability of the dome of the Capilla de Villaviciosa. The work may give some clues to art and architectural historians to understand better the origin and development of Islamic dome architecture.

Clean Coal Technologies Scenario and Evaluation of Present CO2 Dwindling Initiatives to Approach Zero Emission Power Stations By Coal Combustion. Deployment Situation and Evaluation Study

In the present uncertain global context of reaching an equal social stability and steady thriving economy, power demand expected to grow and global electricity generation could nearly double from 2005 to 2030. Fossil fuels will remain a significant contribution on this energy mix up to 2050, with an expected part of around 70% of global and ca. 60% of European electricity generation. Coal will remain a key player. Hence, a direct effect on the considered CO2 emissions business-as-usual scenario is expected, forecasting three times the present CO2 concentration values up to 1,200ppm by the end of this century. Kyoto protocol was the first approach to take global responsibility onto CO2 emissions monitoring and cap targets by 2012 with reference to 1990. Some of principal CO2emitters did not ratify the reduction targets. Although USA and China spur are taking its own actions and parallel reduction measures. More efficient combustion processes comprising less fuel consuming, a significant contribution from the electricity generation sector to a CO2 dwindling concentration levels, might not be sufficient. Carbon Capture and Storage (CCS) technologies have started to gain more importance from the beginning of the decade, with research and funds coming out to drive its come in useful. After first researching projects and initial scale testing, three principal capture processes came out available today with first figures showing up to 90% CO2 removal by its standard applications in coal fired power stations. Regarding last part of CO2 reduction chain, two options could be considered worthy, reusing (EOR & EGR) and storage. The study evaluates the state of the CO2 capture technology development, availability and investment cost of the different technologies, with few operation cost analysis possible at the time. Main findings and the abatement potential for coal applications are presented. DOE, NETL, MIT, European universities and research institutions, key technology enterprises and utilities, and key technology suppliers are the main sources of this study. A vision of the technology deployment is presented.

Transfer of the HIV-1 cyclophilin-binding site to simian immunodeficiency virus from Macaca mulatta can confer both cyclosporin sensitivity and cyclosporin dependence

HIV-1 specifically incorporates the peptidyl prolyl isomerase cyclophilin A (CyPA), the cytosolic receptor for the immunosuppressant cyclosporin A (CsA). HIV-1 replication is inhibited by CsA as well as by nonimmunosuppressive CsA analogues that bind to CyPA and interfere with its virion association. In contrast, the related simian immunodeficiency virus SIVmac, which does not interact with CyPA, is resistant to these compounds. The incorporation of CyPA into HIV-1 virions is mediated by a specific interaction between the active site of the enzyme and the capsid (CA) domain of the HIV-1 Gag polyprotein. We report here that the transfer of HIV-1 CA residues 86–93, which form part of an exposed loop, to the corresponding position in SIVmac resulted in the efficient incorporation of CyPA and conferred an HIV-1-like sensitivity to a nonimmunosuppressive cyclosporin. HIV-1 CA residues 86–90 were also sufficient to transfer the ability to efficiently incorporate CyPA, provided that the length of the CyPA-binding loop was preserved. However, the resulting SIVmac mutant required the presence of cyclosporin for efficient virus replication. The results indicate that the presence or absence of a type II tight turn adjacent to the primary CyPA-binding site determines whether CyPA incorporation enhances or inhibits viral replication. By demonstrating that CyPA-binding-site residues can induce cyclosporin sensitivity in a heterologous context, this study provides direct in vivo evidence that the exposed loop between helices IV and V of HIV-1 CA not merely constitutes a docking site for CyPA but is a functional target of this cellular protein.

Bimodal regulation of Na+–Ca2+ exchanger by β-adrenergic signaling pathway in shark ventricular myocytes

In shark heart, the Na+–Ca2+ exchanger serves as a major pathway for both Ca2+ influx and efflux, as there is only rudimentary sarcoplasmic reticulum in these hearts. The modulation of the exchanger by a β-adrenergic agonist in whole-cell clamped ventricular myocytes was compared with that of the Na+–Ca2+ exchanger blocker KB-R7943. Application of 5 μM isoproterenol and 10 μM KB-R7943 suppressed both the inward and the outward Na+–Ca2+ exchanger current (INa−Ca). The isoproterenol effect was mimicked by 10 μM forskolin. Isoproterenol and forskolin shifted the reversal potential (Erev) of INa−Ca by approximately −23 mV and −30 mV, respectively. An equivalent suppression of outward INa−Ca by KB-R7943 to that by isoproterenol produced a significantly smaller shift in Erev of about −4 mV. The ratio of inward to outward exchanger currents was also significantly larger in isoproterenol- than in control- and KB-R7943-treated myocytes. Our data suggest that the larger ratio of inward to outward exchanger currents as well as the larger shift in Erev with isoproterenol results from the enhanced efficacy of Ca2+ efflux via the exchanger. The protein kinase A-mediated bimodal regulation of the exchanger in parallel with phosphorylation of the Ca2+ channel and enhancement of its current may have evolved to satisfy the evolutionary needs for accelerated contraction and relaxation in hearts of animals with vestigial sarcoplasmic Ca2+ release stores.

Expression of Tobacco Carbonic Anhydrase in the C4 Dicot Flaveria bidentis Leads to Increased Leakiness of the Bundle Sheath and a Defective CO2-Concentrating Mechanism

Flaveria bidentis (L.) Kuntze, a C4 dicot, was genetically transformed with a construct encoding the mature form of tobacco (Nicotiana tabacum L.) carbonic anhydrase (CA) under the control of a strong constitutive promoter. Expression of the tobacco CA was detected in transformant whole-leaf and bundle-sheath cell (bsc) extracts by immunoblot analysis. Whole-leaf extracts from two CA-transformed lines demonstrated 10% to 50% more CA activity on a ribulose-1,5-bisphosphate carboxylase/oxygenase-site basis than the extracts from transformed, nonexpressing control plants, whereas 3 to 5 times more activity was measured in CA transformant bsc extracts. This increased CA activity resulted in plants with moderately reduced rates of CO2 assimilation (A) and an appreciable increase in C isotope discrimination compared with the controls. With increasing O2 concentrations up to 40% (v/v), a greater inhibition of A was found for transformants than for wild-type plants; however, the quantum yield of photosystem II did not differ appreciably between these two groups over the O2 levels tested. The quantum yield of photosystem II-to-A ratio suggested that at higher O2 concentrations, the transformants had increased rates of photorespiration. Thus, the expression of active tobacco CA in the cytosol of F. bidentis bsc and mesophyll cells perturbed the C4 CO2-concentrating mechanism by increasing the permeability of the bsc to inorganic C and, thereby, decreasing the availability of CO2 for photosynthetic assimilation by ribulose-1,5-bisphosphate carboxylase/oxygenase.

Induction and Regulation of Expression of a Low-CO2-Induced Mitochondrial Carbonic Anhydrase in Chlamydomonas reinhardtii

The time course of and the influence of light intensity and light quality on the induction of a mitochondrial carbonic anhydrase (CA) in the unicellular green alga Chlamydomonas reinhardtii was characterized using western and northern blots. This CA was expressed only under low-CO2 conditions (ambient air). In asynchronously grown cells, the mRNA was detected 15 min after transfer from air containing 5% CO2 to ambient air, and the 21-kD polypeptide was detected on western blots after 1 h. When transferred back to air containing 5% CO2, the mRNA disappeared within 1 h and the polypeptide was degraded within 3 d. Photosynthesis was required for the induction in asynchronous cultures. The induction increased with light up to 500 μmol m−2 s−1, where saturation occurred. In cells grown synchronously, however, expression of the mitochondrial CA was also detected in darkness. Under such conditions the expression followed a circadian rhythm, with mRNA appearing in the dark 30 min before the light was turned on. Algae left in darkness continued this rhythm for several days.

Direct modulation of calmodulin targets by the neuronal calcium sensor NCS-1.

Ca2+ and its ubiquitous intracellular receptor calmodulin (CaM) are required in the nervous system, among a host of cellular responses, for the modulation of several important enzymes and ion channels involved in synaptic efficacy and neuronal plasticity. Here, we report that CaM can be replaced by the neuronal calcium sensor NCS-1 both in vitro and in vivo. NCS-1 is a calcium binding protein with two Ca(2+)-binding domains that shares only 21% of homology with CaM. We observe that NCS-1 directly activates two Ca2+/CaM-dependent enzymes (3':5'-cyclic nucleotide phosphodiesterase and protein phosphatase calcineurin). Co-activation of nitric oxide synthase by NCS-1 and CaM results in a higher activity than with CaM alone. Moreover, NCS-1 is coexpressed with calcineurin and nitric oxide synthase in several neuron populations. Finally, injections of NCS-1 into calmodulin-defective cam1 Paramecium partially restore wildtype behavioral responses. With this highly purified preparation of NCS-1, we have obtained crystals suitable for crystallographic structure studies. NCS-1, despite its very different structure, distribution, and Ca(2+)-binding affinity as compared with CaM, can substitute for or potentiate CaM functions. Therefore, NCS-1 represents a novel protein capable of mediating multiple Ca(2+)-signaling pathways in the nervous system.

Activation of the Lck tyrosine protein kinase by hydrogen peroxide requires the phosphorylation of Tyr-394.

Exposure of cells to H2O2 mimics many of the effects of treatment of cells with extracellular ligands. Among these is the stimulation of tyrosine phosphorylation. In this study, we show that exposure of cells to H2O2 increases the catalytic activity of the lymphocyte-specific tyrosine protein kinase p56lck (Lck) and induces tyrosine phosphorylation of Lck at Tyr-394, the autophosphorylation site. Using mutant forms of Lck, we found that Tyr-394 is required for H2O2-induced activation of Lck, suggesting that phosphorylation of this site may activate Lck. In addition, H2O2 treatment induced phosphorylation at Tyr-394 in a catalytically inactive mutant of Lck in cells that do not express endogenous Lck. This demonstrates that a kinase other than Lck itself is capable of phosphorylating Lck at the so-called autophosphorylation site and raises the possibility that this as yet unidentified tyrosine protein kinase functions as an activator of Lck. Such an activating enzyme could play an important role in signal transduction in T cells.

Retro and retroenantio analogs of cecropin-melittin hybrids.

Hybrid analogs of cecropin A (CA) and melittin (M), which are potent antibacterial peptides, have been synthesized. To understand the structural requirements for this antibacterial activity, we have also synthesized the enantio, retro, and retroenantio isomers of two of the hybrids and their N-terminally acetylated derivatives. All analogs of CA(1-13)M(1-13)-NH2 were as active as the parent peptide against five test bacterial strains, but one bacterial strain was resistant to the retro and retroenantio derivatives. Similarly, all analogs of CA(1-7)M(2-9)-NH2 were active against four strains, while two strains were resistant to the retro and retroenantio analogs containing free NH3+ end groups, but acetylation restored activity against one of them. From these data it was concluded that chirality of the peptide was not a critical feature, and full activity could be achieved with peptides containing either all L- or all D-amino acids in their respective right-handed or left-handed helical conformations. For most of the bacterial strains, the sequence of these peptides or the direction of the peptide bonds could be critical but not both at the same time. For some strains, both needed to be conserved.

Sex, sin and salvation : a case study of the narrative pictorial cycle of Saint Mary the Egyptian at Bourges Cathedral

This paper studies the narrative stained glass cycle of the Life of Saint Mary the Egyptian at Bourges Cathedral within the context of prevailing—and often conflicting--civil and ecclesiastical attitudes toward sex, sexual sin, and prostitution in early thirteenth century France. Although the Church maintained that sexual sin was mortal sin, civil records suggest the public was skeptical. Through the example of a penitent harlot, this window, both structurally and in thematic content, attempts to map a doctrinally appropriate path from sexual sin to purity of spirit—and salvation—through complete submission to the Church and its clergy.

St. Louis, Missouri, 1895 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: The Matthews-Northrup up-to-date map of St. Louis MO. It was published by Matthews-Northrup Co in 1895. Scale [ca. 1:95,040]. Covers also a portion of East Saint Louis, Stites, and Madison, Illinois. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Missouri East State Plane Coordinate System NAD83 (in Feet) (Fipszone 2401). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, street car lines, drainage, selected public buildings, parks, cemeteries, and more. Includes index to hotels, prominent buildings and institutions, churches, and places of amusement. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Leicester, Massachusetts, 1855 (Image 1 of 2) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Map of the town of Leicester, Worcester County, Massachusetts, by E.M. Woodford. It was published by Richard Clark in 1855. Scale [ca. 1:15,840]. This layer is image 1 of 2 total images, representing the southern portion of the two sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town district boundaries, and more. Relief is shown by hachures. Includes views of local buildings in margins. Includes also insets: Plan of Leicester. Scale [ca. 1:4,060] -- Plan of Clappville. Scale [ca. 1:4,060]. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

Leicester, Massachusetts, 1855 (Image 2 of 2) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Map of the town of Leicester, Worcester County, Massachusetts, by E.M. Woodford. It was published by Richard Clark in 1855. Scale [ca. 1:15,840]. This layer is image 2 of 2 total images, representing the northern portion of the two sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town district boundaries, and more. Relief is shown by hachures. Includes views of local buildings in margins. Includes also insets: Plan of Leicester. Scale [ca. 1:4,060] -- Plan of Clappville. Scale [ca. 1:4,060]. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.