Barnacle cement: a polymerization model based on evolutionary concepts.

Enzymes and biochemical mechanisms essential to survival are under extreme selective pressure and are highly conserved through evolutionary time. We applied this evolutionary concept to barnacle cement polymerization, a process critical to barnacle fitness that involves aggregation and cross-linking of proteins. The biochemical mechanisms of cement polymerization remain largely unknown. We hypothesized that this process is biochemically similar to blood clotting, a critical physiological response that is also based on aggregation and cross-linking of proteins. Like key elements of vertebrate and invertebrate blood clotting, barnacle cement polymerization was shown to involve proteolytic activation of enzymes and structural precursors, transglutaminase cross-linking and assembly of fibrous proteins. Proteolytic activation of structural proteins maximizes the potential for bonding interactions with other proteins and with the surface. Transglutaminase cross-linking reinforces cement integrity. Remarkably, epitopes and sequences homologous to bovine trypsin and human transglutaminase were identified in barnacle cement with tandem mass spectrometry and/or western blotting. Akin to blood clotting, the peptides generated during proteolytic activation functioned as signal molecules, linking a molecular level event (protein aggregation) to a behavioral response (barnacle larval settlement). Our results draw attention to a highly conserved protein polymerization mechanism and shed light on a long-standing biochemical puzzle. We suggest that barnacle cement polymerization is a specialized form of wound healing. The polymerization mechanism common between barnacle cement and blood may be a theme for many marine animal glues.

An Investigation into the Optimum Thickness of Titanium Dioxide Thin Films Synthesized by Using Atmospheric Pressure Chemical Vapour Deposition for Use in Photocatalytic Water Oxidation

Twenty eight films of titanium dioxide of varying thickness were synthesised by using atmospheric pressure chemical vapour deposition (CVD) of titanium(IV) chloride and ethyl acetate onto glass and titanium substrates. Fixed reaction conditions at a substrate temperature of 660 degrees C were used for all depositions, with varying deposition times of 5-60 seconds used to control the thickness of the samples. A sacrificial electron acceptor system composed of alkaline sodium persulfate was used to determine the rate at which these films could photo-oxidise water in the presence of 365 nm light. The results of this work showed that the optimum thickness for CVD films on titanium substrates for the purposes of water oxidation was approximate to 200 nm, and that a platinum coating on the reverse of such samples leads to a five-fold increase in the observed rate of water oxidation.

Intra-uterine growth restriction and increased risk of hypertension in adult life: A follow-up study of 50-year-olds

OBJECTIVE:

To compare blood pressure between 50-year-old adults who were born at term (37-42 weeks of gestation) with intra-uterine growth restriction (IUGR; birth weight <10th centile) and a control group of similar age born at term without IUGR (birth weight =10th centile).

STUDY DESIGN:

Controlled comparative study.

METHODS:

Participants included 232 men and women who were born at the Royal Maternity Hospital, Belfast, a large regional maternity hospital in Northern Ireland, between 1954 and 1956. One hundred and eight subjects who were born with IUGR were compared with 124 controls with normal birth weight for gestation. The main outcome measures were systolic and diastolic blood pressure at approximately 50 years of age, measured according to European recommendations.

RESULTS:

The IUGR group had higher systolic and diastolic blood pressure than the control group: 131.5 [95% confidence interval (CI) 127.9-135.1] vs 127.1 (95% CI 124.3-129.2) mmHg and 82.3 (95% CI 79.6-85.0) vs 79.0 (95% CI 77.0-81.0) mmHg, respectively. After adjustment for gender, the differences between the groups were statistically significant: systolic blood pressure 4.5 (95% CI 0.3-8.7) mmHg and diastolic blood pressure 3.4 (95% CI 0.2-6.5) mmHg (both P < 0.05). More participants in the IUGR group were receiving treatment for high blood pressure compared with the control group [16 (15%) vs 11 (9%)], although this was not statistically significant. The proportion of subjects with blood pressure >140/90 mmHg or currently receiving antihypertensive treatment was 45% (n = 49) for the IUGR group, and 31% (n = 38) for the control group (odds ratio 1.9, 95% CI 1.1-3.3). Adjustment for potential confounders made little difference.

CONCLUSIONS:

IUGR is associated with higher blood pressure at 50 years of age. Individuals born with IUGR should have regular blood pressure screening and early treatment as required. Hypertension remains underdiagnosed and undertreated in adult life.

Catalyst-Free Photoredox Addition-Cyclisations: Exploitation of Natural Synergy between Aryl Acetic Acids and Maleimide

Suitably functionalised carboxylic acids undergo a previously unknown photoredox reaction when irradiated with UVA in the presence of maleimide. Maleimide was found to synergistically act as a radical generating photoxidant and as a radical acceptor, negating the need for an extrinsic photoredox catalyst. Modest to excellent yields of the product chromenopyrroledione, thiochromenopyrroledione and pyrroloquinolinedione derivatives were obtained in thirteen preparative photolyses. In situ NMR spectroscopy was used to study each reaction. Reactant decay and product build-up were monitored, enabling reaction profiles to be plotted. A plausible mechanism, whereby photo-excited maleimide acts as an oxidant to generate a radical ion pair, has been postulated and is supported by UV/Vis. spectroscopy and DFT computations. The radical-cation reactive intermediates were also characterised in solution by EPR spectroscopy.

Oxidation and glycoxidation of phosphatidylserine and their effect in immune response : a lipidomic approach

Phosphatidylserine (PS) is a member of the class of phospholipids, and is distributed among all cells of mammalians, playing important roles in diverse biological processes, including blood clotting and apoptosis. When externalized, PS is a ligand that is recognized on apoptotic cells. It has been considered that before externalization PS is oxidized and oxPS enhance the recognition by macrophages receptors, however the knowledge about oxidation of PS is still limited. PS, like others phospholipids, has two fatty acyl chains and one polar head group, in this case is the amino acid serine. The modifications in PS structure can occur by oxidation of the unsaturated fatty acyl chains and by glycation of the polar head group, due to free amine group, thus increasing the susceptibility to oxidative events. The main goal of this work was to characterize and identify oxidized and glycoxidized PS, contributing to the knowledge of the biological role of oxidation products of PS, as well as of glycated PS, in immune and inflammatory processes. To achieve this goal, PS standards (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho- L-serine (POPS), 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine (DPPS), 1- palmitoyl-2-linoleoyl-sn-glycero-3-phospho-L-serine (PLPS) and 1-palmitoyl-2- arachidonoyl-sn-glycero-3-phospho-L-serine (PAPS)) and glycated PS (PAPS and POPS) were induced to oxidize in model systems, using different oxidant reagents: HO• and 2,2'-azobis-2-methyl-propanimidamide dihydrochloride (AAPH) . The detailed structural characterization of the oxidative products was performed by ESI-MS and MS/MS coupled to separation techniques such as off line TLC-MS and on line LC-MS, in order to obtained better characterization of the larger number of PS and glycated PS oxidation products. The results obtained in this work allowed to identify several oxidation products of PS and glycated PS with modifications in unsaturated fatty acyl chain. Also, oxidation products formed due to structural changes in the serine polar head with formation of terminal acetamide, terminal hydroperoxyacetaldehyde.and terminal acetic acid (glycerophosphacetic acid, GPAA) were identified. The mass spectrometric specific fragmentation pathway of each type of oxidation product was determined using different mass spectrometry approaches. Based on the identified fragmentation pathways, targeted lipidomic analysis was performed to detect oxidation products modified in serine polar head in HaCaT cell line treated with AAPH. The GPAA was detected in HaCaT cells treated with AAPH to induce oxidative stress, thus confirming that modifications in PS polar head is possible to occur in biological systems. Furthermore, it was found that glycated PS species are more prone to oxidative modifications when compared with non glycated PS. During oxidation of glycated PS, besides the oxidation in acyl chains, new oxidation products due to oxidation of the glucose moiety were identified, including PS advanced glycation end products (PSAGES). To investigate if UVA oxidative stress exerted changes in the lipidome of melanoma cell lines, particularly in PS profile, a lipidomic analysis was performed. The lipid profile was obtained using HILIC-LC-MS and GC-MS analysis of the total lipid extracts obtained from human melanoma cell line (SKMEL- 28) after UVA irradiation at 0, 2 and 24 hours. The results did not showed significant differences in PS content. At molecular level, only PS (18:0:18:1) decreased at the moment of irradiation. The most significant changes in phospholipids content occurred in phosphatidylcholines (PC) and phosphatidylinositol (PI) classes, with an increase of mono-unsaturated fatty acid (MUFA), similarly as observed for the fatty acid analysis. Overall, these data indicate that the observed membrane lipid changes associated with lipogenesis after UVA exposure may be correlated with malignant transformations associated with cancer development and progression. Despite of UVA radiation is associated with oxidative damage, in this work was not possible observe oxidation phospholipids. The anti/pro-inflammatory properties of the oxidized PLPS (oxPLPS) versus non-oxidized PLPS were tested on LPS stimulated RAW 264.7 macrophages. The modulation of intracellular signaling pathways such as NF-kB and MAPK cascades by oxPLPS and PS was also examined in this study. The results obtained from evaluation of anti/pro-inflammatory properties showed that neither PLPS or oxPLPS species activated the macrophages. Moreover only oxidized PLS were found to significantly inhibit NO production and iNOS and il1β gene transcription induced by LPS. The analysis at molecular level showed that this was the result of the attenuation of LPS-induced c-Jun-N-terminal kinase (JNK) and p65 NF-kB nuclear translocation. Overall these data suggest that oxPLPS, but not native PLPS, mitigates pro-inflammatory signaling in macrophages, contributing to containment of inflammation during apoptotic cell engulfment. The results obtained in this work provides new information on the modifications of PS, facilitating the identification of oxidized species in complex samples, namely under physiopathologic conditions and also contributes to a better understanding of the role of oxPS and PS in the inflammatory response, in the apoptotic process and other biological functions.

Cape Verde coastal ecosystem: a study of community structure, trophic interactions and exploitation pattern

Tese de dout., Ciências e Tecnologia das Pescas, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2005

Impact of a cis-associated gene expression SNP on chromosome 20q11.22 on bipolar disorder susceptibility, hippocampal structure and cognitive performance.

BackgroundBipolar disorder is a highly heritable polygenic disorder. Recent enrichment analyses suggest that there may be true risk variants for bipolar disorder in the expression quantitative trait loci (eQTL) in the brain.AimsWe sought to assess the impact of eQTL variants on bipolar disorder risk by combining data from both bipolar disorder genome-wide association studies (GWAS) and brain eQTL.MethodTo detect single nucleotide polymorphisms (SNPs) that influence expression levels of genes associated with bipolar disorder, we jointly analysed data from a bipolar disorder GWAS (7481 cases and 9250 controls) and a genome-wide brain (cortical) eQTL (193 healthy controls) using a Bayesian statistical method, with independent follow-up replications. The identified risk SNP was then further tested for association with hippocampal volume (n = 5775) and cognitive performance (n = 342) among healthy individuals.ResultsIntegrative analysis revealed a significant association between a brain eQTL rs6088662 on chromosome 20q11.22 and bipolar disorder (log Bayes factor = 5.48; bipolar disorder P = 5.85×10(-5)). Follow-up studies across multiple independent samples confirmed the association of the risk SNP (rs6088662) with gene expression and bipolar disorder susceptibility (P = 3.54×10(-8)). Further exploratory analysis revealed that rs6088662 is also associated with hippocampal volume and cognitive performance in healthy individuals.ConclusionsOur findings suggest that 20q11.22 is likely a risk region for bipolar disorder; they also highlight the informative value of integrating functional annotation of genetic variants for gene expression in advancing our understanding of the biological basis underlying complex disorders, such as bipolar disorder.

Baremación de una escala para la orientación heurística VS algorítmica con una muestra de adultos universitarios.

El presente estudio tiene como objetivo ahondar en el conocimiento de los procesos de pensamiento de los seres humanos, concretamente en lo que se refiere a la diferenciación entre las formas de razonamiento heurístico y algorítmico. Se sigue el modelo propuesto por Groner (1991). 191 personas (licenciados y estudiantes universitarios) menores de 26 años; de ellos 103 eran mujeres y 88 hombres. Del total de la muestra, 101 personas realizaron un retest de la escala a los 60 minutos y las restantes 90 personas a los 30 días. Teniendo en cuenta el carácter exploratorio de este estudio se plantearon las siguientes hipótesis: 1. La adaptación a Lengua Española de la escala de orientación heurística de Groner, manteniendo la misma metodología, obtendrá el mismo factor bipolar obtenido en la muestra Suiza, explicando un porcentaje de varianza similar; 2. Una mejora de la metodología empleada permitirá una explicación más adecuada del constructo subyacente; 3. Existe un constructo de razonamiento general, que incorpora dos factores, uno algorítmico y otro heurístico. Escala de orientación heurística de Groner and Groner. En la primera fase (réplica al estudio suizo) se reprodujeron los análisis realizados por el grupo investigador suizo: fiabilidad de la escala, frecuencias de categorías por ítems, análisis factorial y reducción de la escala, correlaciones de las puntuaciones de la escala en las distintas versiones. Segunda fase (replanteamiento metodológico): depuración de ítems, depuración de sujetos, fiabilidad de la escala, estructuración factorial de la escala. 1. La réplica de la metodología utilizada por Groner en la construcción de la escala genera, en nuestro estudio, la reproducción de los resultados obtenidos en Suiza. 2. Esta adaptación, a la Lengua Española, no consigue apresar el factor bipolar del tipo de razonamiento humano, propuesto por Groner. 3. La versión reducida a 30 ítems, siguiendo las propuestas metodológicas de Groner y Groner, tampoco consigue apresar dicho factor. 4. La estructura factorial extraída en la primera fase de nuestra investigación responde a los dos tipos de razonamiento propuestos por Groner, pero sin producirse la dicotomización del factor. 5. La utilización de una metodología diferente mejora el modelo de Groner a nivel explicativo. 6. La versión reducida resultante del replanteamiento metodológico de la investigación, consigue apresar el constructo sugerido en la investigación Suiza. 7. El constructo de razonamiento humano resultante consta de dos factores, uno heurístico general y otro algorítmico, en vez de un único factor bipolar que los recoja. 8. Sin embargo, estos factores parecen no existir ante un análisis más estricto (de ecuaciones estructurales). Parece claro que el devenir del razonamiento humano camina por otros derroteros en las últimas décadas que lo que plantea el prometedor modelo de Groner, tanto en la literatura cognitiva como en la inteligencia artificial. Sin embargo, con las modificaciones metodológicas que planteamos nosotros, los resultados parecen esperanzadores.

Baremación de una escala para la orientación heurística VS algorítmica con una muestra de adultos no universitarios.

Este trabajo se encuadra, desde el punto de vista teórico, en el contexto de razonamiento humano, y dentro de él en el campo del llamado razonamiento heurístico, entendido como una dimensión del estilo cognitivo para la población canaria de la 'escala de razonamiento heurístico', elaborada por Groner y Groner (1991), como instrumento de medida de tal dimensión. Participaron 148 personas no universitarias, de un gran abanico de profesiones, mayores de 25 años. La primera parte del trabajo presenta una reflexión teórica en torno a la concepción del razonamiento heurístico, a fin de realizar un intento de operacionalizar tal concepto-constructo, como paso previo para su medida. En el segundo capítulo se describe un instrumento de medida surgido en 1991, elaborado por el suizo, Groner que tiene como finalidad diferenciar entre sujetos cuyo razonamiento siga una pauta de carácter heurístico frente a aquella cuya estrategia es algorítmica. Se expone cuál ha sido el desarrollo de la escala original suiza y sus características estadísticas. Los siguientes capítulos se dedican al método empleado en este estudio, para la posible estandarización de la escala en Lengua Castellana. 'Escala de razonamiento heurístico' de Groner y Groner (1991). 1. La réplica de la metodología utilizada por Groner y Groner genera en nuestro estudio la reproducción de los resultados obtenidos en Suiza. 2. Esta adaptación no logra apresar el factor bipolar del tipo de razonamiento humano propuesto por ellos (al igual que la escala original). La versión reducida de 30 ítems tampoco consigue apresar dicho factor. 3. La utilización de una metodología diferente mejora el modelo de Groner a nivel explicativo, pero mantiene las incongruencias teóricas detectadas en su metodología. 4. La estructura factorial de la primera fase de esta investigación responde a los dos tipos de razonamiento propuestos por Groner, pero sin producirse la dicotomización del factor. 5. La versión reducida resultante del replanteamiento metodológico de la investigación, consigue apresar el constructo surgido en la investigación suiza, a nivel empírico. 6. El constructo de razonamiento humano obtenido con la nueva versión de la escala consta de tres factores, uno de razonamiento heurístico general y dos algorítmicos, en vez de un único factor bipolar que los recoja. 7. El instrumento de medida propuesto en este trabajo, no permite diferenciar entre sujetos con modos de razonamiento diferenciales. No existen estilos cognitivos definidos que puedan englobarse en las definiciones propuestas de razonamiento heurístico VS algorítmico. Los datos derivados de las distintas depuraciones a que sometimos la escala parecen indicar dicha afirmación, si bien hay que hacer la salvedad de que la escala debería ser rechazada totalmente si se quiere verificar un nuevo modelo, por ejemplo el modelo de Evans (1984) o Kauswisher (1989) que contempla la interacción 'conocimiento previo x características impuestas por la tarea'.

The genetic basis of resistance to anticoagulants in rodents

Anticoagulant compounds, i.e., derivatives of either 4-hydroxycoumarin (e.g., warfarin, bromadiolone) or indane-1,3-dione (e.g., diphacinone, chlorophacinone), have been in worldwide use as rodenticides for > 50 years. These compounds inhibit blood coagulation by repression of the vitamin K reductase reaction (VKOR). Anticoagulant-resistant rodent populations have been reported from many countries and pose a considerable problem for pest control. Resistance is transmitted as an autosomal dominant trait although, until recently, the basic genetic mutation was unknown. Here, we report on the identification of eight different mutations in the VKORC1 gene in resistant laboratory strains of brown rats and house mice and in wild-caught brown rats from various locations in Europe with five of these mutations affecting only two amino acids (Tyr139Cys, Tyr139Ser, Tyr139Phe and Leu128Gln, Leu128Ser). By recombinant expression of VKORC1 constructs in HEK293 cells we demonstrate that mutations at Tyr139 confer resistance to warlarin at variable degrees while the other mutations, in addition, dramatically reduce VKOR activity. Our data strongly argue for at least seven independent mutation events in brown rats and two in mice. They suggest that mutations in VKORC1 are the genetic basis of anticoagulant resistance in wild populations of rodents, although the mutations alone do not explain all aspects of resistance that have been reported. We hypothesize that these mutations, apart from generating structural changes in the VKORC1 protein, may induce compensatory mechanisms to maintain blood clotting. Our findings provide the basis for a DNA-based field monitoring of anticoagulant resistance in rodents.

Dietary monounsaturated fatty acids and haemostasis

Diets high in monounsaturated fatty acids (MUFA) are increasingly being recommended as a highly-effective cholesterol-lowering strategy in populations at risk of CHD. However, the need for a re-appraisal of the benefits of diets rich in MUFA became apparent as a result of recent studies showing that meals high in olive oil cause greater postprandial activation of blood coagulation factor VII than meals rich in saturated fatty acids. The present review evaluates the evidence for the effects of MUFA-rich diets on fasting and postprandial measurements of haemostasis, and describes data from a recently-completed long-term controlled dietary intervention study. The data show that a background diet high in MUFA has no adverse effect on fasting haemostatic variables and decreases the postprandial activation of factor VII in response to a standard fat-containing meal. Since the same study also showed a significant reduction in the ex vivo activation of platelets in subjects on the high-MUFA diet, the overall findings suggest that there is no reason for concern regarding adverse haemostatic consequences of high-MUFA diets.