Morfología de la costa atlántica entre Punta Ninfas y Cabo Dos Bahías

Se describen y analizan genéticamente las unidades morfológicas entre punta Ninfas y cabo Dos Bahías, a lo largo de aproximadamente 300 km del litoral costero de la provincia del Chubut. Estas unidades se desarrollaron en un ambiente con clima semiárido y escasos cursos hídricos temporarios, con excepción del río Chubut. Para determinarlas se emplearon cartas geológicas y morfológicas, fotografías aéreas y relevamientos in situ. Los componentes definidos se clasificaron según criterios morfológicos en unidades continentales y marinas, éstas últimas, con carácter activo e inactivo. En este contexto se reconocieron entre otras unidades, mesetas, depresiones, valles, acantilados, playas y cordones litorales. Las características evolutivas señaladas en los rasgos morfológicos remanentes indican que la morfología inició su desarrollo en el Pleistoceno y que durante el Holoceno ocurrieron dos ciclos marinos cuyos efectos quedaron registrados tanto en las formas antiguas como en las actuales.A description and genetic analysis of the morphological units present in the northwestern coastal area of Chubut province, between Punta Ninfas and Cabo Dos Bahías, along 300 km approximately, were carried out. This work aims to define the processes that have acted to shape the different geomorphological features of the area. Also, based on the morphological traits evaluate changes in sea level that took place during the Quaternary. In a semiarid environment, with temporary water courses with the exception of the Chubut River, several morphological units were developed. Morphological and geological maps, aerial photographs (1:20.000 scale) and in situ detailed surveys data were used to determine the units present in the area. Topographical profiles between tide levels using the Emery method adapted to large beaches were performed and morphological examinations into the continent were made up to about 10 km from the coast. Tectonically, are classified as Trailing edge coasts. According to its structure are rugged coastlines. Correspond to coasts under the action of storm waves caused by winds reach 10 m/s. Among the morphological units continental and marine types were recognized. The continental forms are integrated by terraces, depressions, valleys and gullys. Among the marine units active and inactive units were found. The active marine units determined were: cliffs, beach ridges, beaches, wave-cut platforms, coastal dunes and tombolos. The inactive marine units determined were: palaeo cliffs, coastal lagoons and raised beaches. In the morphological modeling area have involved reactivation tectonic processes in conjunction with changes in sea level. The structures of positive and negative relief would be linked to tectonic reactivation occurred during the Pleistocene. The Holocene initiate with a transgressive cycle; towards the middle Holocene around 6000 yr BP began a regressive cycle leaving raised beaches, boulder beds and coastal lagoons in sedimentary silting process. One last ingressive cycle between 4000 and 2000 BP have modeled some bays, beach ridges, wave-cut platforms and notches originated at the foot of the cliffs. The presence of a step in the abrasion wave-cut platforms may be an index of sea level fall and a current period of stabilization. At present, marine erosion is favored in jointed wave-cut platforms. Sedimentary material generated by marine erosion (sand and pebbles) are transported by the action of longshore drift. To the northern sector of the study area the beaches are open type while southward pocked beaches are dominant. Cliff top dunes occur in bays closed by cliffs.Fil: Schillizzi, Roberto Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Spagnuolo, Jorge Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentina. Universidad Nacional del Sur. Departamento de Geología; ArgentinaFil: Luna, L.. Universidad Nacional del Sur. Departamento de Geología; Argentin

Phenotypic and Gene Expression Profiles of Embryo Development of the Ascidian Ciona robusta Exposed to Dispersants

Within EU approval policies, most dispersant ecotoxicity testing considers lethal concentrations for marine adult species, overlooking the embryotoxicological effects. Here we studied the ecotoxicity of two commercial dispersant formulations (dispersant A and B) on the embryogenesis of the ascidian Ciona robusta. Embryotoxicity and phenotypic alterations stated that dispersant B resulted more toxic than A (EC50 value of 44.30 and 160 µg mL−1, respectively) and induced severe larvae malformations at lower concentrations. Furthermore, the analysis of genes involved in different cellular response pathways indicated that those belonging to biotransformation were upregulated by dispersant A treatment, likely related to the presence of hydrocarbons. Instead, dispersant B induced cas8 gene downregulation, probably as a result of the prolonged exposure to mixture components. Our preliminary findings support the use of the C. robusta embryotoxicity test as a valuable tool for dispersant approval procedures, by providing sub-lethal responses on marine invertebrates closely related to vertebrates

Assignment of the binding site for Haptoglobin on Apolipoprotein A-I

Haptoglobin (Hpt) was previously found binding the high-density lipoprotein (HDL) Apolipoprotein A-I (ApoA-I) and able to inhibit the ApoA-I-dependent activity of the enzyme Lecithin:Cholesterol Acyl-Transferase (LCAT), which plays a major role in the reverse cholesterol transport. The ApoA-I structure was analyzed for detecting the site bound by Hpt. ApoA-I was treated by cyanogen bromide or hydroxylamine and the resulting fragments, separated by electrophoresis or gel filtration, were tested by Western blotting or ELISA for their ability to bind Hpt. The ApoA-I sequence from Glu113 to Asn184 harbored the binding site for Hpt. Biotinylated peptides were synthesized overlapping such a sequence, and their Hpt binding activity was determined by avidin-linked peroxidase. The highest activity was exhibited by the peptide P2a, containing the ApoA-I sequence from Leu141 to Ala164. Such a sequence contains an ApoA-I domain required for binding cells, promoting cholesterol efflux, and stimulating LCAT. The peptide P2a effectively prevented both binding of Hpt to HDL-coated plastic wells and Hpt-dependent inhibition of LCAT, measured by anti-Hpt antibodies and cholesterol esterification activity respectively. The enzyme activity was not influenced, in the absence of Hpt, by P2a. Differently from ApoA-I or HDL, the peptide did not compete with Hemoglobin for Hpt binding in ELISA experiments. The results suggest that Hpt might mask the ApoA-I domain required for LCAT stimulation, thus impairing the HDL function. Synthetic peptides, able to displace Hpt from ApoA-I without altering its property of binding Hemoglobin, might be used for treatment of diseases associated with defective LCAT function

MicroRNA profiling in sera of patients with type 2 diabetes mellitus reveals an upregulation of miR-31 expression in subjects with microvascular complications

Type 2 diabetes (T2D) is a metabolic disease characterized by chronic hyperglycaemia due to a combination of resistance to insulin action and an inadequate compensatory insulin secretory response. Chronic hyperglycemia is associated with long-term micro- and macrovascular complications leading to dysfunction of several organs including kidney, heart, eye and nervous system. Early identification of chronic diabetic complications is necessary in order to prevent dysfunction and failure of these different organs. MicroRNAs (or miRNAs) are small endogenous RNAs, which negatively regulate gene expression. Recently, it has been demonstrated that miRNAs can be secreted by cells, thus being detectable in serum and in other biological fluids. Circulating microRNAs have been proposed as possible biomarkers of several diseases. Here, we performed a miRNAs expression profiling in the sera of T2D patients with or without vascular complications in order to find specific biomarkers to characterize T2D complications. We analyzed the expression of 384 microRNAs in serum pools from 3 groups of T2D patients: 12 T2D patients without any chronic complications, 12 T2D patients with macrovascular complications and 12 with microvascular complications. We found 223 miRNAs expressed in T2D,224 inT2D with microvascular and221 inT2D with macrovascular complications. Among expressed microRNAs, 45 resulted upregulated and 23 downregulated in microvascular patients sera, while 13 upregulated and 41 downregulated in macrovascular T2D patients compared to those without complications. We focused and validated microRNA miR-31 expression in single sera from each group, which resulted significantly upregulated in patients with microvascular complications and may be indeed related to the presence of microangiopathy. In conclusion, our study has identified miR-31 as a promising biomarker for diabetic microvascular complications; further prospective studies in the clinical setting are however required to establish the real utility of measuring serum circulating levels of this microRNA

Polyphenols as potential agents in the management of temporomandibular disorders

Temporomandibular disorders (TMD) consist of multifactorial musculoskeletal disorders associated with the muscles of mastication, temporomandibular joint (TMJ), and annexed structures. This clinical condition is characterized by temporomandibular pain, restricted mandibular movement, and TMJ synovial inflammation, resulting in reduced quality of life of affected people. Commonly, TMD management aims to reduce pain and inflammation by using pharmacologic therapies that show efficacy in pain relief but their long-term use is frequently associated with adverse effects. For this reason, the use of natural compounds as an effective alternative to conventional drugs appears extremely interesting. Indeed, polyphenols could represent a potential therapeutic strategy, related to their ability to modulate the inflammatory responses involved in TMD. The present work reviews the mechanisms underlying inflammation-related TMD, highlighting the potential role of polyphenols as a promising approach to develop innovative management of temporomandibular diseases

Coordination and spin state equilibria as a function of pH, ionic strength, and protein concentration in oxidized dimeric Scapharca inaequivalvis hemoglobin.

The oxidized homodimeric Scapharca inaequivalvis hemoglobin undergoes changes in coordination and spin state as a function of pH, ionic strength, and protein concentration which have been monitored by optical absorption spectroscopy. Three species contribute to the spectra between pH 5.8 and 8.7: (i) a hexacoordinate high spin aquomet derivative, whose concentration is essentially constant over the whole pH range analyzed; (ii) a pentacoordinate high spin component which prevails at alkaline pH values, and (iii) a hexacoordinate low spin hemichrome, which is formed at acid pH. The contribution of each of the components to the observed spectra was calculated with the singular value decomposition procedure and has been described quantitatively in terms of a linkage scheme which accounts for the change in heme coordination and for the observation that the high spin to low spin transition entails dissociation into monomers. An important feature of the linkage scheme is the cooperative binding of protons to aquomet dimers. Stopped flow experiments to study the kinetics indicate that dissociation into monomers is the rate-limiting process. The unusually strong tendency of oxidized HbI to loose the heme-bound water molecule is discussed in terms of strain in the iron-proximal histidine bond

Structural characterization of oxidized dimeric Scapharca inaequivalvis hemoglobin by resonance Raman spectroscopy.

Resonance Raman spectra of the ferric homodimeric hemoglobin from Scapharca inaequivalvis have been measured over the pH range 5.8-8.3 in buffers of ionic strengths 0.01 and 0.1 M to determine the spin and coordination state of the iron atom. Three species contribute to the spectra: a low spin hexacoordinate, a high spin pentacoordinate, and a high spin hexacoordinate component. Optical absorption and EPR spectra measured under the same conditions allowed the identification of the ligands in the sixth coordination position, namely the distal histidine in the low spin derivative and a water molecule in the high spin one. The relative concentrations of these three species depend on pH in an unusual way. Thus, the aquomet derivative is present over the whole pH range, albeit in small amounts as most of the hemoglobin converts to the low spin hemichrome at acid pH values and to the pentacoordinate derivative at neutral and slightly alkaline ones. The formation of a pentacoordinate heme as the pH is increased has not been reported previously for other myoglobins and hemoglobins. Low ionic strength and high protein concentration favor the formation of the high spin pentacoordinate species, while at high ionic strength and low protein concentration the low spin hexacoordinate species prevails. Ionization of the iron-bound water molecule occurs at pH > or = 9.3; accordingly, signals from the hydroxyl derivative were not observed in the Raman spectra over the pH range studied