Ion balance in waters through inductively coupled plasma optical emission spectrometry

Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) has been employed to carry out the determination of both major anions and cations in water samples. The anion quantification has been performed by means of a new automatic accessory. In this device chloride has been determined by continuously adding a silver nitrate solution. As a result solid silver chloride particles are formed and retained on a nylon filter inserted in the line. The emission intensity is read at a silver characteristic wavelength. By plotting the drop in silver signal versus the chloride concentration, a straight line is obtained. As regards bicarbonate, this anion has been on-line transformed into carbon dioxide with the help of a 2.0 mol L−1 nitric acid stream. Carbon signal is linearly related with bicarbonate concentration. Finally, information about sulfate concentration has been achieved by means of the measurement of sulfur emission intensity. All the steps have been simultaneously and automatically performed. With this setup detection limits have been 1.0, 0.4 and 0.09 mg L−1 for chloride, bicarbonate and sulfate, respectively. Furthermore, it affords good precision with RSD below 6 %. Cation (Ca, Mg, Na and K) concentration, in turn, has been obtained by simultaneously reading the emission intensity at characteristic wavelengths. The obtained limits of detection have been 8 × 10−3, 2 × 10−3, 8 × 10−4 and 10−2 mg L−1 for sodium, potassium, magnesium and calcium, respectively. As regards sample throughput, about 30 samples h−1 can be analysed. Validation results have revealed that the obtained concentrations for these anions are not significantly different as compared to the data provided by conventional methods. Finally, by considering the data for anions and cations, precise ion balances have been obtained for well and mineral water samples.

Modifications post-traductionnelles des canaux calciques cardiaques de type L : identification des résidus asparagine qui participent à la glycosylation de la sous-unité auxiliaire CaVα2δ1

Les canaux calciques de type L CaV1.2 sont principalement responsables de l’entrée des ions calcium pendant la phase plateau du potentiel d’action des cardiomyocytes ventriculaires. Cet influx calcique est requis pour initier la contraction du muscle cardiaque. Le canal CaV1.2 est un complexe oligomérique qui est composé de la sous-unité principale CaVα1 et des sous-unités auxiliaires CaVβ et CaVα2δ1. CaVβ joue un rôle déterminant dans l’adressage membranaire de la sous-unité CaVα1. CaVα2δ1 stabilise l’état ouvert du canal mais le mécanisme moléculaire responsable de cette modulation n’a pas été encore identifié. Nous avons récemment montré que cette modulation requiert une expression membranaire significative de CaVα2δ1 (Bourdin et al. 2015). CaVα2δ1 est une glycoprotéine qui possède 16 sites potentiels de glycosylation de type N. Nous avons donc évalué le rôle de la glycosylation de type-N dans l’adressage membranaire et la stabilité de CaVα2δ1. Nous avons d’abord confirmé que la protéine CaVα2δ1 recombinante, telle la protéine endogène, est significativement glycosylée puisque le traitement à la PNGase F se traduit par une diminution de 50 kDa de sa masse moléculaire, ce qui est compatible avec la présence de 16 sites Asn. Il s’est avéré par ailleurs que la mutation simultanée de 6/16 sites (6xNQ) est suffisante pour 1) réduire significativement la densité de surface de! CaVα2δ1 telle que mesurée par cytométrie en flux et par imagerie confocale 2) accélérer les cinétiques de dégradation telle qu’estimée après arrêt de la synthèse protéique et 3) diminuer la modulation fonctionnelle des courants générés par CaV1.2 telle qu’évaluée par la méthode du « patch-clamp ». Les effets les plus importants ont toutefois été obtenus avec les mutants N663Q, et les doubles mutants N348Q/N468Q, N348Q/N812Q, N468Q/N812Q. Ensemble, ces résultats montrent que Asn663 et à un moindre degré Asn348, Asn468 et Asn812 contribuent à la biogenèse et la stabilité de CaVα2δ1 et confirment que la glycosylation de type N de CaVα2δ1 est nécessaire à la fonction du canal calcique cardiaque de type L.

Geochemistry at DSDP Sites 69-505, 69-504 and 70-504

Deep basement penetration during Legs 69 and 70 at Hole 504B in the Panama Basin allowed the recovery of a 561.5-meter sequence of basaltic pillows, thin flows, and breccias interspersed with thick massive flows. The lavas, which are aphyric to moderately plagioclase-olivine-clinopyroxene phyric, are petrologically indistinguishable from typical mid-ocean-ridge basalts (MORB). Some units are distinctive in that they carry accessory chrome-spinel microphenocrysts or emerald green clinopyroxene phenocrysts. Major and trace element analyses were carried out on 67 samples using X-ray fluorescence techniques. The basalts resemble normal MORB in terms of major elements. However, the trace element analyses show that most of the basalts are characterized by very strong depletion in the more incompatible elements compared with, for instance, normal (N type) MORB from the Atlantic at 22°N. Interdigitated with these units are one or two units that have distinctly higher incompatible element concentrations similar to those in basalts of the transitional (T) type from the Reykjanes Ridge (63°N in the Mid-Atlantic Ridge). All the basalts appear to have undergone some high-level crystal fractionation, although this has not proceeded to the extent of yielding ferrobasalts as it has at the adjacent Galapagos Spreading Center or along the East Pacific Rise. The magnetic anomalies are of lower amplitude than in the latter two regions, which suggests that the absence of ferrobasalts may be a general feature of the ocean crust generated at the Costa Rica Rift. The presence of two distinct magma types, one strongly depleted and the other moderately enriched in incompatible elements, suggests that magma chambers at the spreading center are discontinuous rather than continuous and that there is some chemical heterogeneity in the underlying mantle source. Observed variations in incompatible element ratios of basalts from the more depleted group could, however, reflect mixing between these two magma types. In general it would appear that the mantle feeding the Costa Rica Rift is significantly more depleted in incompatible trace elements than that feeding the Mid-Atlantic Ridge.

A new crocodilian from the Lower Cretaceous Crato Formation of north-eastern Brazil

A new mesosuchian crocoddian from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian) of north-eastern Brazil is described. Susisuchus anatoceps gen. et sp. nov. is the first crocodillan to be reported from this formation. It is represented by an incomplete, partially articulated skeleton: the skull and mandible, partial postcranial axial skeleton, forelimbs and portions of the osteodermal skeleton. Preservation of soft tissues includes the skin surrounding both forelimbs and the digits of the right hand. The state of preservation of the specimen suggests that it was incorporated into the basin as a desiccated carcass. Susisuchus anatoceps is one of the oldest crocodilians with a eusuchian-type dorsal shield, comprising a tetraserial paravertebral shield and, either side of this, two sagittal rows of accessory osteoderms. It also possesses amphicoelous thoracic, lumbar and caudal vertebrae. This combination of postcranial features have never before been seen in a crocodilian and warrant the erection of a new family within Mesosuchia: Susisuchidae. Taxonomically, S. anatoceps is similar to a number of Lower Cretaceous mesosuchians previously considered to have given rise to eusuchians, most notably the Glen Rose crocodilian and a new, but as yet undescribed crocodillan from the Lower Cretaceous Winton Formation of western Queensland, Australia. Preliminary preparation of the Winton crocodilian indicates that it may belong to Susisuchidae, supporting the hypotheses of interchange between the vertebrate faunas of South America and Australia during the Lower Cretaceous.

Patients with chronic neck pain demonstrate altered patterns of muscle activation during performance of a functional upper limb task

Study Design. Cross-sectional study. Objective. This study compared neck muscle activation patterns during and after a repetitive upper limb task between patients with idiopathic neck pain, whiplash-associated disorders, and controls. Summary of Background Data. Previous studies have identified altered motor control of the upper trapezius during functional tasks in patients with neck pain. Whether the cervical flexor muscles demonstrate altered motor control during functional activities is unknown. Methods. Electromyographic activity was recorded from the sternocleidomastoid, anterior scalenes, and upper trapezius muscles. Root mean square electromyographic amplitude was calculated during and on completion of a functional task. Results. A general trend was evident to suggest greatest electromyograph amplitude in the sternocleidomastoid, anterior scalenes, and left upper trapezius muscles for the whiplash-associated disorders group, followed by the idiopathic group, with lowest electromyographic amplitude recorded for the control group. A reverse effect was apparent for the right upper trapezius muscle. The level of perceived disability ( Neck Disability Index score) had a significant effect on the electromyographic amplitude recorded between neck pain patients. Conclusions. Patients with neck pain demonstrated greater activation of accessory neck muscles during a repetitive upper limb task compared to asymptomatic controls. Greater activation of the cervical muscles in patients with neck pain may represent an altered pattern of motor control to compensate for reduced activation of painful muscles. Greater perceived disability among patients with neck pain accounted for the greater electromyographic amplitude of the superficial cervical muscles during performance of the functional task.

Microspectrophotometry of visual pigments and oil droplets in a marine bird, the wedge-tailed shearwater Puffinus pacificus: Topographic variations in photoreceptor spectral characteristics

Microspectrophotometric examination of the retina of a procellariiform marine bird, the wedge-tailed shearwater Puffinus pacificus, revealed the presence of five different types of vitamin A(1)-based visual pigment in seven different types of photoreceptor. A single class of rod contained a medium-wavelength sensitive visual pigment with a wavelength of maximum absorbance (lambda(max)) at 502 nm. Four different types of single cone contained visual pigments maximally sensitive in either the violet (VS, lambda(max) 406 nm), short (SWS, lambda(max) 450 nm), medium (MWS, lambda(max) 503 nm) or long (LWS, lambda(max) 566 nm) spectral ranges. In the peripheral retina, the SWS, MWS and LWS single cones contained pigmented oil droplets in their inner segments with cut-off wavelengths (lambda(cut)) at 445 (C-type), 506 (Y-type) and 562 nm (R-type), respectively. The VS visual pigment was paired with a transparent (T-type) oil droplet that displayed no significant absorption above at least 370 run. Both the principal and accessory members of the double cone pair contained the same 566 nm lambda(max) visual pigment as the LWS single cones but only the principal member contained an oil droplet, which had a lambda(cut) at 413 nm. The retina had a horizontal band or 'visual streak' of increased photoreceptor density running across the retina approximately 1.5 mm dorsal to the top of the pecten. Cones in the centre of the horizontal streak were smaller and had oil droplets that were either transparent/colourless or much less pigmented than at the periphery. It is proposed that the reduction in cone oil droplet pigmentation in retinal areas associated with high visual acuity is an adaptation to compensate for the reduced photon capture ability of the narrower photoreceptors found there. Measurements of the spectral transmittance of the ocular media reveal that wavelengths down to at least 300 nm would be transmitted to the retina.

The origin and evolution of the surfactant system in fish: Insights into the evolution of lungs and swim bladders

Several times throughout their radiation fish have evolved either lungs or swim bladders as gas-holding structures. Lungs and swim bladders have different ontogenetic origins and can be used either for buoyancy or as an accessory respiratory organ. Therefore, the presence of air-filled bladders or lungs in different groups of fishes is an example of convergent evolution. We propose that air breathing could not occur without the presence of a surfactant system and suggest that this system may have originated in epithelial cells lining the pharynx. Here we present new data on the surfactant system in swim bladders of three teleost fish ( the air-breathing pirarucu Arapaima gigas and tarpon Megalops cyprinoides and the non-air-breathing New Zealand snapper Pagrus auratus). We determined the presence of surfactant using biochemical, biophysical, and morphological analyses and determined homology using immunohistochemical analysis of the surfactant proteins (SPs). We relate the presence and structure of the surfactant system to those previously described in the swim bladders of another teleost, the goldfish, and those of the air-breathing organs of the other members of the Osteichthyes, the more primitive air-breathing Actinopterygii and the Sarcopterygii. Snapper and tarpon swim bladders are lined with squamous and cuboidal epithelial cells, respectively, containing membrane-bound lamellar bodies. Phosphatidylcholine dominates the phospholipid (PL) profile of lavage material from all fish analyzed to date. The presence of the characteristic surfactant lipids in pirarucu and tarpon, lamellar bodies in tarpon and snapper, SP-B in tarpon and pirarucu lavage, and SPs ( A, B, and D) in swim bladder tissue of the tarpon provide strong evidence that the surfactant system of teleosts is homologous with that of other fish and of tetrapods. This study is the first demonstration of the presence of SP-D in the air-breathing organs of nonmammalian species and SP-B in actinopterygian fishes. The extremely high cholesterol/disaturated PL and cholesterol/PL ratios of surfactant extracted from tarpon and pirarucu bladders and the poor surface activity of tarpon surfactant are characteristics of the surfactant system in other fishes. Despite the paraphyletic phylogeny of the Osteichthyes, their surfactant is uniform in composition and may represent the vertebrate protosurfactant.

Interaction of the Hsp90 cochaperone cyclophilin 40 with Hsc70

The high-affinity ligand-binding form of unactivated steroid receptors exists as a multicomponent complex that includes heat shock protein (Hsp)90; one of the immunophilins cyclophilin 40 (CyP40), FKBP51, or FKBP52; and an additional p23 protein component. Assembly of this heterocomplex is mediated by Hsp70 in association with accessory chaperones Hsp40, Hip, and Hop. A conserved structural element incorporating a tetratricopeptide repeat (TPR) domain mediates the interaction of the immunophilins with Hsp90 by accommodating the C-terminal EEVD peptide of the chaperone through a network of electrostatic and hydrophobic interactions. TPR cochaperones recognize the EEVD structural motif common to both Hsp90 and Hsp70 through a highly conserved clamp domain. In the present study, we investigated in vitro the molecular interactions between CyP40 and FKBP52 and other stress-related components involved in steroid receptor assembly, namely Hsp70 and Hop. Using a binding protein-retention assay with CyP40 fused to glutathione S-transferase immobilized on glutathione-agarose, we have identified the constitutively expressed form of Hsp70, heat shock cognate (Hsc)70, as an additional target for CyP40. Deletion mapping studies showed the binding determinants to be similar to those for CyP40-Hsp90 interaction. Furthermore, a mutational analysis of CyP40 clamp domain residues confirmed the importance of this motif in CyP40-Hsc70 interaction. Additional residues thought to mediate binding specificity through hydrophobic interactions were also important for Hsc70 recognition. CyP40 was shown to have a preference for Hsp90 over Hsc70. Surprisingly, FKBP52 was unable to compete with CyP40 for Hsc70 binding, suggesting that FKBP52 discriminates between the TPR cochaperone-binding sites in Hsp90 and Hsp70. Hop, which contains multiple units of the TPR motif, was shown to be a direct competitor with CyP40 for Hsc70 binding. Similar to Hop, CyP40 was shown not to influence the adenosine triphosphatase activity of Hsc70. Our results suggest that CyP40 may have a modulating role in Hsc70 as well as Hsp90 cellular function.

Branchial vascular pathways in two species of Tetraodontiformes and the concept of secondary vessels and nutrient arteries

The vascular organisation of the branchial basket was examined in two Tetraodontiform fishes; the three-barred porcupinefish, Dicotylichthys punctulatus and the banded toadfish, Marylina pleurosticta by scanning electron microscopy of vascular casts and standard histological approaches. In D. punctulatus, interarterial anastomoses (iaas) originated at high densities from the efferent filamental and branchial arteries, subsequently re-anastomosing to form progressively larger secondary vessels. Small branches of this system entered the filament body, where it was interspersed between the intrafilamental vessels. Large-bore secondary vessels ran parallel with the efferent branchial arteries, and were found to constitute an additional arterio-arterial pathway, in that these vessels exited the branchial basket in company with the mandibular, the carotid and the afferent and efferent branchial arteries, from where they gave rise to capillary beds after exit. Secondary vessels were not found to supply filament muscle; rather these tissues were supplied by single specialised vessels running in parallel between the efferent and afferent branchial arteries in both species examined. Although the branchial vascular anatomy was generally fairly similar for the two species examined, iaas were not found to originate from any branchial component in the banded toadfish, M. pleurosticta, which instead showed a moderate frequency of iaas on other vessels in the cephalic region. It is proposed that four independent vascular pathways may be present within the teleostean gill filament, the conventional arterio-arterial pathway across the respiratory lamellae; an arterio-arterial system of secondary vessels supplying the filament and non-branchial tissues; a system of vessels supplying the filament musculature; and the intrafilamental vessels (central venous sinus). The present study demonstrates that phylogenetic differences in the arrangement of the branchial vascular system occur between species of the same taxon.

Sperm ultrastructure of the Actinocyclidae (Mollusca, Nudibranchia) and homology of the terminal region of nudibranch sperm

Sperm ultrastructure is examined and described for the actinocyclidid nudibranchs Actinocyclus verrucosus, Hallaxa iju and Hallaxa indecora. Although general characteristics were consistent with previously described heterobranch observations, present investigations revealed ultrastructural synapomorphies for the family based on the morphology of the terminal region of the spermatozoon. In actinocyclidids, the axonemal microtubules penetrate for some distance beyond the annulus, and the annular accessory body elongates to completely seal the terminal region. Chromodoris also has an annular accessory body that completely seals the axoneme and terminal region, but it does not extend far beyond the annulus, and it is possible that these states were derived independently. Cytochemical staining confirmed that there was no glycogen present in the posterior region of the sperm for H. indecora or Chromodoris kuniei. However, representatives of other chromodoridid genera (Noumea, Risbecia) have an axoneme that penetrates through the entire annular complex, after which it is sheathed by a glycogen deposit. Similarities in the acrosomal complex support the proposed sister group relationship between the Actinocyclidae and Chromodorididae.

Microchemistry and microstructures of hydrothermally altered shock-metamorphosed basement gneiss, Woodleigh impact structure, Southern Carnarvon Basin, Western Australia

Hydrothermally altered shock-metamorphosed gneisses consisting of relic igneous biotite-K-feldspor-Na-rich alkali feldspar - plagioclase - quartz assemblages ( accessory garnet, corundum, titanite, monazite, zircon), and showing extensive replacement by montmorillonite, illite, sericite, and to a lesser extent chlorite, calcite, epidote, zoisite and pyrite, occur in the basement core uplift of the Woodleigh impact structure, Western Australia. The rocks display extensive hydrothermal clay alteration, complicating identification of pre-hydrothermal and pre-impact textures and compositions. Analysis of quartz-hosted planar deformation features (PDFs) indicates a majority of indexed sets parallel to omega{10 (1) over bar3}, a lesser abundance of sets parallel to pi{10 (1) over bar2}, and some sets parallel to the basal plane (0001) and r,z {10 (1) over bar1}, consistent with pressures about or over 20 GPa. Feldspar-hosted FDFs form reticulate vein networks displaying checkerboard-like to irregular and serrated patterns attributable to preferential replacement of shock-damaged PDFs and/or perthitic twin lamella by clay minerals. The gneisses are pervaded by clay-dominated intergranular and intragranular veins of cryptocrystalline material that display marked departures from bulk-rock chemistry and from mineral compositions. XRD analysis identifies the cryptocrystalline components as illite - montmorillonite, illite and chlorite, while laser Raman analysis identifies high-fluorescence sub-micrometre clay assemblage, feldspar, quartz and minor mica. SEM/EDS-probe and laser-ICPMS analysis indicate low-K high-Mg clay mineral compositions consistent with montmorillonite. Quartz PDF-hosted cryptocrystalline laminae display distinct enrichments in Al, Mg, Ca and K. Altered intergranular veins and feldspar-hosted cryptocrystalline components show consistent enrichment in the relatively refractory elements (Al, Cc, Mg, Fe) and depletion in relatively volatile elements (Si, K, Na). The clay alteration retards determination whether clay-dominated vein networks represent altered shock-induced pseudotachylite veins, diaplectic zones and/or shock-damaged twin lamella, and/or result from purely mineralogical and chemical differentiation affected by hydrothermal fluids, Overall enrichment of the shocked gneiss and of the cryptocrystalline components in Mg and trace ferromagnesian elements (Ni, Cc, Cr) may be attributed alternatively to introduction of siderophile element-rich fluid from the projectile, or/and contamination of hydrothermal fluids by MgO from dolomites surrounding the basement uplift. High Ni/Co and Ni/Cr and anomalous DGE (platinum group elements) may support the former model.

Expression and role of complex carbohydrates in axon guidance in the olfactory system

Primary sensory neurons in the vertebrate olfactory systems are characterised by the differential expression of distinct cell surface carbohydrates. We show here that the histo-blood groups Sda (or CT1 antigen) and H are expressed by primary sensory neurons in the olfactory system, while the blood group A carbohydrate is expressed by a subset of vomeronasal neurons only in the developing accessory olfactory system. We have used both loss-of-function and gain-of-function approaches to manipulate expression of these carbohydrates in the olfactory system. In null mutant mice lacking the alpha(1,2)fucosyltransferase FUT1, the blood group H and A carbohydrates were not expressed in the olfactory systems which caused delayed development of the nerve fibre and glomerular layers in the main olfactory bulb. In contrast, ubiquitous expression of blood group A on olfactory axons in gain-of-function transgenic mice perturbed the ability of vomeronasal axons to terminate in the accessory olfactory bulb and affected the selective targeting of axons in the main olfactory bulb. During regeneration following bulbectomy, vomeronasal axons were unable to effectively sort out from the main olfactory axons when blood group A was misexpressed. These results provide in vivo evidence for a role of specific cell surface carbohydrates during development and regeneration of the olfactory nerve pathways.

Genetic manipulation of blood group carbohydrates alters development and pathfinding of primary sensory axons of the olfactory systems

Primary sensory neurons in the vertebrate olfactory systems are characterised by the differential expression of distinct cell surface carbohydrates. We show here that the histo-blood group H carbohydrate is expressed by primary sensory neurons in both the main and accessory olfactory systems while the blood group A carbohydrate is expressed by a subset of vomeronasal neurons in the developing accessory olfactory system. We have used both loss-of-function and gain-of-function approaches to manipulate expression of these carbohydrates in the olfactory system. In null mutant mice lacking the alpha(1,2)fucosyltransferase FUT1, the absence of blood group H carbohydrate resulted in the delayed maturation of the glomerular layer of the main olfactory bulb. In addition, ubiquitous expression of blood group A on olfactory axons in gain-of-function transgenic mice caused mis-routing of axons in the glomerular layer of the main olfactory bulb and led to exuberant growth of vomeronasal axons in the accessory olfactory bulb. These results provide in vivo evidence for a role of specific cell surface carbohydrates during development of the olfactory nerve pathways. (c) 2006 Elsevier Inc. All rights reserved.

Structure and ultrastructure of the silk glands and spinneret of Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

This study provides comprehensive documentation of silk production in the pest moth Helicoverpa armigera from gland secretion to extrusion of silk thread. The structure of the silk glands, accessory structures and extrusion apparatus are reported. The general schema of the paired silk glands follows that found for Lepidoptera. Morphology of the duct, silk press, muscle attachments and spigot are presented as a three-dimensional reconstruction and the cuticular crescent-shaped profile of the silk press is demonstrated in both open and closed forms with attendant muscle blocks, allowing advances in our knowledge of how the silk press functions to regulate the extrusion of silk. Growth of the spigot across instars is documented showing a distinctive developmental pattern for this extrusion device. Its shape and structure are related to use and load-bearing activity. (c) 2005 Elsevier Ltd. All rights reserved.

The detection of environmental autoinducing peptide quorum-sensing genes from an uncultured Clostridium sp in landfill leachate reactor biomass

Aims: To elucidate whether a dominant uncultured clostridial (Clostridium thermocellum-like) species in an environmental sample (landfill leachate), possesses an autoinducing peptide (AIP) quorum-sensing (QS) gene, although it may not be functional. Methods and Results: A modified AIP accessory gene regulator (agr)C PCR protocol was performed on extracted DNA from a landfill leachate sample (also characterized by 16S rRNA gene cloning) and the PCR products were cloned, sequenced and phylogenetically analysed. It appeared that two agrC gene phylotypes existed, most closely related to the C. thermocellum agrC gene, differing by only 1 bp. Conclusions: It is possible to specifically identify and characterize the agrC AIP QS gene from uncultured Firmicutes (C. thermocellum-like) bacteria derived from environmental (landfill leachate) sample. Significance and Impact of the Study: This is the first successful attempt at identifying AIP QS genes from a cellulolytic environment (landfill). The agrC gene was identified as being most closely related to the C. thermocellum agrC gene, the same bacterium identified as being dominant, according to 16S rRNA gene cloning and subsequently fluorescence in situ hybridization analyses, in the same biomass.