Metallothioneins in the clam Ruditapes decussatus: an overview

The clam Ruditapes decussatus is a suspension-feeding bivalve mollusc widely distributed in European waters and in the Mediterranean. Due to is economic importance it is heavily harvested in many countries, and particularly in Portugal. Its ability to accumulate high metal concentrations along with its economic importance was the main reason for its selection as a bioindicator. Metallothionein (MT) concentrations in the clams R. decussatus followed by gel filtration chromatography, differential pulse polarography and SDS-PAGE, after Cd exposure, revealed that MT is induced in different tissues (whole soft tissues, gills, digestive gland and remaining tissues) but the level of MT induction is tissue dependent. MT from the gills and the digestive gland give a more sensitive response to assess the effects of metal exposure directly from the water or from the food than in the whole soft tissues. MT levels were also measured in the gills, digestive gland and remaining tissues of R. decussatus collected in the Ria Formosa lagoon (Portugal) from areas of different metal load and during the period of sexual differentiation of the clam. Data revealed that there were significant differences of MT concentrations among sites and season but not among sex. Purification of MT from the digestive gland of R. decussatus revealed four MT isoforms. The molecular weight of one of these isoforms, determined by SDS-PAGE, was of the same order of magnitude as that of MT from other bivalve species. Similarly the amino acid sequence of the beta domain of the MT of the digestive gland of the clam also shows some degree of similarity with the similar MT sequence from mussels and oysters. It is, therefore suggested that there is some degree of similarity in the MT structure among these species.info:eu-repo/semantics/publishedVersio

Hcv And Drug Transition In Ct Nonurban Injection Drug Users

Aims: We sought to determine if age of first substance initiation (alcohol intoxication, marijuana use, pharmaceutical opioid use, polysubstance) was associated with faster rates of transition to injection drug use or heroin use. Subsequently, we examined if transition time was a predictor for hepatitis C infection. Methods: From 2008-2012, 462 active injection drug users were recruited using respondent-driven sampling. Participants were interviewed about their injection-associated risk, and serological testing of HIV, HCV and HBV was performed. Kaplan-Meier analyses were used to examine the rate of transition from first substance event to initiation of heroin use or first injection. A Cox proportional hazards regression model was used to examine risk of transition, and regression analysis was performed to assess transition time as a predictor of HCV infection. Results: Age of initiation was categorized into young and old based on the median age of the specific substance. Individuals initiating alcohol intoxication, marijuana use, and polysubstance use at older ages had faster transitions to both heroin and injection drug use. Younger pharmaceutical opioid initiates did not have significantly different transition times than older initiates, although the risk of early transition to heroin (AHR=1.7; 95% CI=1.3-2.3) and injection drugs (AHR=2.3; 95% CI=1.7-3.2) was significantly greater in older initiates. The adjusted odds of HCV infection decreased with increasing transition times to injection from initiation of opioid use by 9%, of polysubstance use by 13%, of marijuana use by 9%, and of alcohol intoxication by 8%. Conclusions: Older initiates of pharmaceutical opioids, alcohol intoxication, and marijuana use are at greater risk of early transition to heroin use and injection of any drug than younger initiates, but initiate heroin use and injection at similar ages. Effective prevention strategies aimed at delaying transition to heroin use and injection drug use, particularly in older initiates, are needed to prevent incident HCV infections in this nonurban injection drug user population

Exploring Antecedents of Those Who Practice Servant Leadership

The purpose of the study was to explore the preceding essence of the individual who is a servant leader. In search of antecedents, the researcher used a qualitative method with a phenomenological design, exploring what brought the participants to utilize servant leadership. Furthermore, the researcher aimed to fill a gap by asking participants to provide their stories of what brought them to employ such a leadership style versus suggesting answers. This qualitative research study was conducted to answer the question: What are the antecedents of the person who practices servant leadership? A criterion sample was used to recruit servant leaders through the social media network LinkedIn.com. Three subjects participated in the study and were found to have common antecedents featuring religion and military service combined with personal and educational influences, as well as characteristics such as integrity, compassion, supportive, and responsible. Other commonalities of the participants included planning and training experience, as well as reading, exercise and sleep for self-care

Metabolic interactions between vitamin A and conjugated linoleic acid

Lipid-soluble molecules share several aspects of their physiology due to their common adaptations to a hydrophilic environment, and may interact to regulate their action in a tissue-specific manner. Dietary conjugated linoleic acid (CLA) is a fatty acid with a conjugated diene structure that is found in low concentrations in ruminant products and available as a nutritional supplement. CLA has been shown to increase tissue levels of retinol (vitamin A alcohol) and its sole specific circulating carrier protein retinol-binding protein (RBP or RBP4). However, the precise mechanism of this action has not been elucidated yet. Here, we provide a summary of the current knowledge in this specific area of research and speculate that retinol and CLA may compete for catabolic pathways modulated by the activity of PPAR- and RXR heterodimer. We also present preliminary data that may position PPAR- at the crossroads between the metabolism of lipids and vitamin

Environmental memory from a circadian oscillator:the Arabidopsis thaliana clock differentially integrates perception of photic vs. thermal entrainment

The constraint of a rotating earth has led to the evolution of a circadian clock that drives anticipation of future environmental changes. During this daily rotation, the circadian clock of Arabidopsis thaliana (Arabidopsis) intersects with the diurnal environment to orchestrate virtually all transcriptional processes of the plant cell, presumably by detecting, interpreting, and anticipating the environmental alternations of light and temperature. To comparatively assess differential inputs toward phenotypic and physiological responses on a circadian parameter, we surveyed clock periodicity in a recombinant inbred population modified to allow for robust periodicity measurements after entrainment to respective photic vs. thermal cues, termed zeitgebers. Lines previously thermally entrained generally displayed reduced period length compared to those previously photically entrained. This differential zeitgeber response was also detected in a set of diverse Arabidopsis accessions. Thus, the zeitgebers of the preceding environment direct future behavior of the circadian oscillator. Allelic variation at quantitative trait loci generated significant differences in zeitgeber responses in the segregating population. These were important for periodicity variation dependent on the nature of the subsequent entrainment source. Collectively, our results provide a genetic paradigm for the basis of environmental memory of a preceding environment, which leads to the integrated coordination of circadian periodicity

Data Exploration, Quality Control and Testing in Single-Cell qPCR-Based Gene Expression Experiments

Cell populations are never truly homogeneous; individual cells exist in biochemical states that define functional differences between them. New technology based on microfluidic arrays combined with multiplexed quantitative polymerase chain reactions (qPCR) now enables high-throughput single-cell gene expression measurement, allowing assessment of cellular heterogeneity. However very little analytic tools have been developed specifically for the statistical and analytical challenges of single-cell qPCR data. We present a statistical framework for the exploration, quality control, and analysis of single-cell gene expression data from microfluidic arrays. We assess accuracy and within-sample heterogeneity of single-cell expression and develop quality control criteria to filter unreliable cell measurements. We propose a statistical model accounting for the fact that genes at the single-cell level can be on (and for which a continuous expression measure is recorded) or dichotomously off (and the recorded expression is zero). Based on this model, we derive a combined likelihood-ratio test for differential expression that incorporates both the discrete and continuous components. Using an experiment that examines treatment-specific changes in expression, we show that this combined test is more powerful than either the continuous or dichotomous component in isolation, or a t-test on the zero-inflated data. While developed for measurements from a specific platform (Fluidigm), these tools are generalizable to other multi-parametric measures over large numbers of events.Comment: 9 pages, 5 figure

Respirometrie électrolytique dans le design and exploitation de plants de traitement

La mayoría de sistemas de tratamiento de aguas residuales son procesos con fangos activados. Los tratamientos biológicos con fangos activados eliminan la materia orgánica disuelta y sustancias inorgánicas, sólidos no sedimentables y coloidales. Muchas de estas sustancias, especialmente los xenobióticos, pueden ser muy degradables o ser tóxicas a los microorganismos presentes en las plantas de tratamiento. Se define “Respirometría” como la determinación experimental, junto con la correspondiente interpretación, de la velocidad de consumo biológico de oxígeno bajo condiciones experimentales bien definidas. La respirometría constituye una técnica muy útil tanto para el modelado y operación de los procesos de fangos activados como para la caracterización del agua a tratar, ya que el consumo de oxígeno está asociado directamente con el crecimiento de la biomasa y con la degradación del sustrato.Most of wastewater treatment systems are processes with activated sludge. Biological treatment with activated sludge removes soluble organic matter and inorganic substances, sediment and colloidal solids. Many of these chemicals, especially xenobiotics, can be highly degradable or can be toxic to microorganisms present in treatment plants. "Respirometry" is defined as the experimental determination, together with the interpretation, of the biological oxygen consumption rate under specific experimental conditions. The respirometry is a very useful technique for modelling and operation processes of activated sludge and also for the characterization of the water to be treated, because the oxygen consumption is directly associated with the biomass growth and the substrate degradation.La plupart des systèmes de traitement des eaux usées sont des procès avec des boues activées. Le traitement biologique par boues activées élimine la matière organique dissoute et les substances inorganiques, les sédiments et les matières solides colloïdales. Beaucoup de ces produits chimiques, en particulier les xénobiotiques, peuvent être très dégradables ou être toxiques pour les micro-organismes présents dans les plants de traitement. On définit "Respirométrie" comme la détermination expérimentale, avec l'interprétation de la vitesse de la consommation d'oxygène biologique dans des conditions expérimentales bien définies. La Respirométrie est une technique très utile pour la modélisation et le fonctionnement des processus de boues activées et aussi pour la caractérisation de l'eau à traiter, parce que la consommation d'oxygène est directement liée à la croissance de la biomasse et à la dégradation du substrat.Peer Reviewe