Methodological approach to investigating spatial cognition in Arctic charr (Salvelinus alpinus).

Assessing cognitive traits poses consistent methodological challenges. We describe a method for testing Arctic charr by incorporating a T-maze into their housing, which reduced stress and improved the engagement of the tested fish in the task. We outline the phases of testing to evaluate learning efficiency and determine which orientation strategies, such as motor response versus beaconing, are prioritized by the animals.

How to measure exploration: A combined estimation method.

The personality axis 'exploration-avoidance' is often measured using an open field test (OFT) from which measurements such as mobility level (e.g. distance travelled) and space use (e.

Variation in personality shaped by evolutionary history, genotype and developmental plasticity in response to feeding modalities in the Arctic charr.

Animal personality has been shown to be influenced by both genetic and environmental factors and shaped by natural selection. Currently, little is known about mechanisms influencing the development of personality traits. This study examines the extent to which personality development is genetically influenced and/or environmentally responsive (plastic).

Enhancement of Soybean Meal Alters Gut Microbiome and Influences Behavior of Farmed Atlantic Salmon ().

Atlantic salmon () is one of the worlds most domesticated fish. As production volumes increase, access to high quality and sustainable protein sources for formulated feeds of this carnivorous fish is required. Soybean meal (SBM) and soy-derived proteins are the dominant protein sources in commercial aquafeeds due to their low-cost, availability and favorable amino acid profile.

Personality in juvenile Atlantic cod ecotypes and implications for fisheries management.

Animals show among-individual variation in behaviors, including migration behaviors, which are often repeatable across time periods and contexts, commonly termed "personality." These behaviors can be correlated, forming a behavioral syndrome. In this study, we assessed the repeatability and correlation of different behavioral traits, i.

Activity vs exploration: Locomotion in a known and unknown environment differs in Atlantic cod juveniles (Gadus morhua).

Individuals within a population often behave differently and these differences can be consistent over time and/or context, also termed "animal personality". Animal personality has been commonly classified into five axes with studies aiming to validate these axes. One subject that has surprisingly not received full attention yet is the difference between the two personality axes "activity" and "exploration-avoidance", i.

Torula yeast in the diet of Atlantic salmon Salmo salar and the impact on growth performance and gut microbiome.

Atlantic salmon aquaculture is expanding, and with it, the need to find suitable replacements for conventional protein sources used in formulated feeds. Torula yeast (Cyberlindnera jadinii), has been identified as a promising alternative protein for feed and can be sustainably cultivated on lignocellulosic biomasses. The present study investigated the impact of torula yeast on the growth performance and gut microbiome of freshwater Atlantic salmon.

The effect of ultrasonic antifouling control on the growth and microbiota of farmed European sea bass (Dicentrarchus labrax).

Biofouling is a serious threat to marine renewable energy structures and marine aquaculture operations alike. As an alternative to toxic surface coatings, ultrasonic antifouling control has been proposed as an environmentally friendly means to reduce biofouling. However, the impact of ultrasound on fish farmed in offshore structures or in marine multi-purpose platforms, combining renewable energy production and aquaculture, has not yet been assessed.

Marine aggregates in North Atlantic coast: Microbial characteristics and potential interactions with farmed Atlantic salmon (Salmo salar).

Microbial contamination of aggregates collected near an Atlantic salmon farm, in the Cherbourg roadstead, was followed monthly over one year to study the dynamics of Vibrio spp. and explore their impact on farmed fish. Salmon state of health was followed through blood and histopathological analyses.

Subtle temperature increase can interact with individual size and social context in shaping phenotypic traits of a coldwater fish.

Temperature and individual egg size have been long studied in the development of fishes because of their direct effects on individual fitness. Here we studied the combined effects of three important factors for fish development, i.e.

Relationship between individual and group learning in a marine teleost: A case study with sea bass under self-feeding conditions.

Fish learning and cognition are usually approached by testing single individuals in various devices such as mazes that have serious drawbacks, especially in gregarious species, including the stress induced by the test procedure. This might impair the results and lead to misinterpretation about the learning abilities of the targeted species. In order to provide an alternative to the individual-based tests, we investigated for the first time the operant conditioning of four similar groups (50 individuals per tank) of sea bass.

Heritability of Boldness and Hypoxia Avoidance in European Seabass, Dicentrarchus labrax.

To understand the genetic basis of coping style in European seabass, fish from a full factorial mating (10 females x 50 males) were reared in common garden and individually tagged. Individuals coping style was characterized through behavior tests at four different ages, categorizing fish into proactive or reactive: a hypoxia avoidance test (at 255 days post hatching, dph) and 3 risk-taking tests (at 276, 286 and 304 dph). We observed significant heritability of the coping style, higher for the average of risk-taking scores (h2 = 0.

The shy prefer familiar congeners.

The shy-bold continuum is both a fundamental aspect of human behavior and a relatively stable behavioral trait for many other species. Here we assessed whether shy individuals prefer familiar congeners, taking the European sea bass, a recently domesticated fish showing similar behavioral responses to wild fish, as a model to better understand the inter-individual variability in social behavior previously observed in this species. In the wild, the link between familiarity i.

First Insight into Exploration and Cognition in Wild Caught and Domesticated Sea Bass (Dicentrarchus labrax) in a Maze.

European sea bass aquaculture is so recent that very little is known on the effects of the early steps of its domestication. Behavioural parameters are sensitive indicators of the domestication process since they are generally impacted as soon as the first generation. The present work compared wild-caught and domesticated sea bass juvenile swimming activity, exploration and ability to learn to discriminate between two 2-D objects associated to a simple spatial task that enabled the tested individual to visually interact with an unfamiliar congener (the reward) located behind a transparent wall at the end of one of the two arms of a maze.

Characterization of Ascentis RP-Amide column: Lipophilicity measurement and linear solvation energy relationships.

This study investigates lipophilicity determination by chromatographic measurements using the polar embedded Ascentis RP-Amide stationary phase. As a new generation of amide-functionalized silica stationary phase, the Ascentis RP-Amide column is evaluated as a possible substitution to the n-octanol/water partitioning system for lipophilicity measurements. For this evaluation, extrapolated retention factors, log k'w, of a set of diverse compounds were determined using different methanol contents in the mobile phase.

Effect of n-octanol in the mobile phase on lipophilicity determination by reversed-phase high-performance liquid chromatography on a modified silica column.

In this study, we show that the addition of n-octanol to the mobile phase improves the chromatographic determination of lipophilicity parameters of xenobiotics (neutral solutes, acidic, neutral and basic drugs) on a Phenomenex Gemini C18 column. The Gemini C18 column is a new generation hybrid silica-based column with an extended pH range capability. The wide pH range (2-12) afforded the examination of basic drugs and acidic drugs in their neutral form.

Prolonged glucose requirements after intentional glargine and aspart overdose.

Intentional insulin overdose in diabetic patients is a rather rare critical situation. We report the case of a patient suffering from type 1 diabetes who was found comatose with a plasma glucose close to zero after having injected herself massive doses of both aspart and glargine insulin analogues. The prevention of hypoglycaemic episodes in this patient required a long-term glucose infusion (i.

Acetylcholinesterase-ISFET based system for the detection of acetylcholine and acetylcholinesterase inhibitors.

A bioelectronic hybrid system for the detection of acetylcholine esterase (AChE) catalytic activity was assembled by way of immobilizing the enzyme to the gate surface of an ion-sensitive field-effect transistor (ISFET). Photometric methods used to characterize bonded enzyme and linker layers on silicon substrates confirm the existence of a stable amino-cyanurate containing AChE monolayer. The transduction of the enzyme-functionalized ISFET, in ionic solutions, is detected in response to application of acetylcholine (ACh).

Lumpectomy with tamoxifen as primary treatment for elderly women with early-stage breast cancer.

Background: Appropriate therapy for women over 70 years of age with breast cancer is currently a highly debated topic. The aim of this study was to determine whether a subset of patients could be identified in which lumpectomy alone, followed by tamoxifen, would offer adequate local, regional, and long-term control of disease.

Methods: A retrospective analysis of 171 women over the age of 70 with stage I or II breast carcinomas treated by the senior authors from 1984 to 1998 was undertaken.

Drosophila Rrp1 3'-exonuclease: demonstration of DNA sequence dependence and DNA strand specificity.

Drosophila Rrp1 (recombination repair protein 1) is a DNA repair enzyme whose nuclease activities include AP-endonuclease, 3'-exonuclease, 3'-phosphodiesterase and 3'-phosphatase. This study investigates the sequence specificity of the dsDNA 3'-exonuclease activity of Rrp1. We demonstrate that the activity is more efficient in purine-rich regions of dsDNA than in pyrimidine-rich regions.

Diameter of the cell-to-cell junctional membrane channels as probed with neutral molecules.

The cell-to-cell channels in the junctions of an insect salivary gland and of insect and mammalian cells in culture were probed with fluorescent molecules-neutral linear oligosaccharides, neutral branched glycopeptides, and charged linear peptides. From the molecular dimensions of the largest permeants and smallest impermeants the permeation-limiting channel diameter was obtained: 16 to 20 angstroms for the mammalian cells and 20 to 30 angstroms for the insect cells.

Acetylcholine receptor: modification of synaptic gating mechanism after treatment with a disulfide bond reducing agent.

Reduction of a 'reactive' disulfide bond in the postsyraptic membrane of the frog neuromuscular junction by dithiothreitol (DTT) decreases both the sensitivity of the membrane to applied acetylcholine (ACh) and the amplitude of the single 'shot effect'. Analysis of ACh induced conductance fluctuations in voltage clamped frog endplates indicates that DTT reduces both the amplitude gamma and duration tau of the elementary conductance events. The mean control value of gamma was 18.

Acetylcholine noise: analysis after chemical modification of receptor.

The elementary voltage pulses ("shot effects") produced by the action of acetylcholine molecules on the receptor were studied by analyzing the membrane voltage fluctuations ("noise") after acetylcholine application at the frog neuromuscular junction. The amplitude of these pulses was decreased after treatment with a disulfide-bond reducing agent. The shot effect may thus depend on the structure or conformation of the receptor molecule.