Nou descobriment en l'evolució del sistema immune : Limfòcits que fagociten

La Universitat Autònoma de Barcelona ha participat en un treball de recerca que acaba d'efectuar un descobriment que qüestiona un dels paradigmes de la immunologia dels vertebrats, pel qual la fagocitosi (capacitat d'"ingestió" i destrucció de microbis) s'exercia principalment per cèl·lules fagocítiques "professionals" (macròfags, monòcits, granulòcits), mentre que les cèl·lules productores d'anticossos (limfòcits B) no tenien aquesta capacitat. El descobriment afecta a peixos i amfibis.La Universidad Autónoma de Barcelona ha participado en unainvestigación que acaba de efectuar un descubrimiento que cuestionauno de los paradigmas de la inmunología de los vertebrados por el cualla fagocitosis (capacidad de "ingestión" y destrucción de microbios) seejercía principalmente por células fagocíticas "profesionales"(macrófagos, monocitos, granulocitos), mientras que las célulasproductoras de anticuerpos (linfocitos B) no tenían esta capacidad. Eldescubrimiento afecta a peces y anfibiosThe UAB has taken part in a research project that has just made adiscovery which questions one of the paradigms of vertebrateimmunology, by which phagocytosis (the ability to "ingest" and destroymicrobes) is exercised mainly by "professional" phagocyte cells,monocytes, granulocytes), whilst cells which produce antibodies (Blymphocytes) do not have this ability. This discovery affects fish andamphibians

Metabolisme anaeròbic en peixos sotmesos a contaminació per metalls pesants

Heavy metals have been shown to produce a wide range of effects on fishes and, as a consequence, several mechanisms are developed to compensate such affects. At the metabolic level heavy metal toxicity produces tissue hippoxia, enzymatic disturbance and energy defficiency. Fish responses involve not only the way in which ATP is produced, but also the way in wich ATP is used, as the motor activity or energy expenditure. Aerobic metabolism response involves mostly higher rates of metabolic turnover, enzymatic activity or mitochondrial mass. In anaerobic metabolism strong increases of lactate concentration as well as other anaerobic metabolites as alanine, succinate or ethanol have been described, and alternative anaerobic pathways have been postulated to explain the accumulation of such metabolites. However, as long-term treatments show normal metabolite levels it is suggested that anaerobic metabolism would play a role as a short-term energy source, immediately after metal action, while longterm adaptations in aerobic pathway or in physiological mechanisms take place

Bienestar animal en peces : la controversia alrededor de las de los peces como seres sentientes. Aportaciones de la biología

Se presenta la panorámica actual respecto a las investigaciones biológicas que están desarrollando en los peces para determinar hasta qué punto estos animales son seres sentientes con capacidades de percepción de estrés y dolor. Después de reconocer la amplia diversidad biológica y describir el equipamiento neural y las capacidades cognitivas, se describe el estado actual de la controversia científica alrededor de la capacidad sentiente de los peces.The current overview is presented regarding the biological investigations being carried out in fish to determine whether these animals are sentient beings with capacity to perceive stress and pain. After realising the wide biological diversity and describing the neural equipment and cognitive abilities, the current state of the scientific controversy surrounding the sentient capacity of the fish is described

Evaluación de dos medios bacterianos aceleradores del proceso de nitrificación en filtros biológicos de cultivos marinos

Se evalúan dos medios bacterianos aceleradores del proceso de nitrificación en un sistema de circulación de agua cerrado. Como substrato de crecimiento de las bacterias se estableció una carga de arena viva sobre filtros sernihúmedos y como productores de amonio 17 doradas (Sparus aurata) por tanque de cultivo de 400 L. Los parámetros físico-químicos fueron analizados y registrados del mismo modo para cada uno de los grupos. Los medios bacterianos evaluados fueron Alken Clear Flo 1200 y Biozyme. El tiempo para completar la oxidación del amonio no se redujo en ninguno de los dos tratamientos, pero disminuyó el tiempo para completar la oxidación de los nitritos en Biozyme y aumentó en Alken Clear Flo. La media de concentración basal más baja de amonio y nitrito se obtiene en el tanque tratado con Biozyme seguido del tratado con Alken Clear Flo y el tanque control.Commercial bacterial formulations were added to new seawater tanks with individual recirculating systems, and their ability to accelerate the establishment of nitrification was compared with an untreated control. Crushed shells were used as filter media in biological trickle filters and 17 mediterranean seabreams (Sparus aurata) were introduced in the 400 L tanks as ammonia producers. Physico-chernical parameters were monitored and recorded with the sarne procedure for each of the experimental groups. The time for effective ammonia oxidation was not reduced in any of both treatments, but time of nitrite reduction diminished for Biozyme and increased in Alken Clear Flo. Baseline values for ammonia and nitrite through the experiment were lower for Biozyme, followed by Alken Clear Flo 1200 and control tan

Principals mecanismes de defensa immunitària dels peixos teleostis, amb especial referència a l'orada, Sparus aurata

La conoscenza elel sistema immunitario dei pesci è relazionato soprettutto all'acquicoltura come futura industria di produzione alimentare. In queste installazioni, situate in ambienti marini o lagunari, gli elementi patogeni hanno più facilità di movimento e quindi di trasmettersi e contaminare le specie coltivate. Da qui l'esigenza di approfondire il funzionamento dei meccanismi immunitari dei pesci con scheletro osseo, i teleostei, e nella specie lo Sparus aurata cioè l'orata, molto apprezzata sotto il profilo gastronomico, motivo per il quale si realizzano gli sforzi per estenderne la coltivazione. Il Iavoro di questa équipe di biologi offre già alcune novità della loro ricerca

L'estrès en els peixos : tipus, efectes i paràmetres de mesura

The relevance of stressing procedures and their measurement is emphasized. Types of and responses to stress are presented. After several experiments regarding stressing procedures as grading and hauling, crowding and parasite infection, changes are detected at the levels of primary responses (increase of plasma cortisol), secondary (respiratory, hematological and metabolic alterations) and tertiary responses (decrease of activity and growth).Es destaca la importància de l'estrès en els peixos i el seu mesurament. Després d'indicar les modalitats d'estrès, es descriuen els tipus de respostes. En diferents experiments on s'estudiaven procediments estressants com la classificació i el transport, l'apinyament o la infecció parasitària, es detecten respostes primàries (augment del cortisol plasmàtic), secundàries (alteracions respiratòries, hematològiques i metabòliques) i terciaries (disminució de l'activitat i el creixement)

Fish health challenge after stress : indicators of immunocompetence

Changes in the nervous and endocrine systems of fish after stress episodes have consequences on their immune system and thereby affect the ability to maintain immunocompetence. Fish mainly depend upon innate immune responses, which include a rich and powerful array of mechanisms, that appear to be more potent than in higher vertebrates. Thus, fish provide a unique model to understand the evolution of immune defence system. When the organism is challenged by an antigen or by stressors, a number of responses of reactive nature are engaged in an attempt to counteract the threat and recover homeostasis. However, if the challenge is maintained, changes in the immune system become chronic, and suppression can be observed in several key immune mechanisms, leading to maladaptation. Therefore, the time factor is of key importance in immune assessment. Taking into account this dynamic pattern of infection and stress, specific indicators should be identified in order to detect functional changes in the immune system. Furthermore, there is a need for specific markers that reflect either activation in the initial stages or suppression in response to a chronic challenge.Els canvis en els sistemes nerviós i endocrí després d'episodis d'estrès generen conseqüències en el sistema immunitari que influeixen en la capacitat de mantenir la immunocompetència. Els peixos depenen especialment de la resposta immunitària innata, un ampli conjunt de mecanismes que sembla que actuïn amb més potència que en vertebrats superiors. Així, els peixos es troben en una posició evolutiva única per a comprendre els models de mecanismes de defensa en els vertebrats. Quan l'organisme és afectat per un antigen o per situacions que provoquen estrès, s'inicien una sèrie de respostes de naturalesa reactiva per a contrarestar-ne els efectes i recobrar l'homeòstasi. Altrament, els canvis en el sistema immunitari esdevenen crònics i es pot observar una depressió en alguns mecanismes immunitaris que acaben amb una mala adaptació. Per tant, el factor temps és clau en la determinació de la resposta immunitària. Tenint en compte aquest patró dinàmic en la infecció i l'estrès, és important determinar indicadors específics que detectin canvis funcionals del sistema immunitari dels peixos. Els marcadors més apropiats són els que indiquen tant una activació dels mecanismes immunitaris en els estadis inicials com una depressió en situacions cròniques

Diferències morfomètriques i merístiques entre l'orada cultivada i salvatge

Gilthead seabream is of high commercíal interest and has become an important aquacultural resource in the Mediterranean countries. Now, the aim of improving the quality of reared products in order to meet markets preferences of conformity with wild standards is a new priority, The aim of this study is the use of morphometrics and meristics for the quantification of the differences in quality assessment and on their causative factors between and within sea bream reared in different fish farms and wild standards. Reared S.auratus show higher body depth, caudal peduncle depth, last dorsal spine, anal fin rays number and position of first anal spine respect to dorsal, and lower head depth, snout length, preorbital length, predorsal length, dorsal fin base, pectoral fin length, ventral fin length, caudal peduncle length, scales berween lateral line and dorsal, pectoral fin rays number and largest dorsal fin spine than wild sea bream. Apart of this measures, Cupimar hatchery facility has fish with lower head length, interorbital length and distance between pelvic and pectoral fins than wild sea bream; Maresa hatchery físhes have lower anal fin base and higher head length than wild standards, Blanes Peix sea cages show lower head length, orbital diameter and interorbital length than wild standards; and Aquadelt fishes show lower head length, orbital diameter, interorbital length, distance berween pelvic and pectoral fins and preanal length than wild sea bream and a non significant difference in last dorsal spine

Polystyrene nanoplastics accumulate in ZFL cell lysosomes and in zebrafish larvae after acute exposure, inducing a synergistic immune response in vitro without affecting larval survival in vivo

Altres ajuts: pre-doctoral scholarship from UAB (2018FI_B_00711)The presence of small-sized plastic particles in marine and freshwater environments is a global problem but their long-term impact on ecosystems and human health is still far from being understood. Nanoplastics (<1000 nm) could pose a real and uncontrolled ecological challenge due to their smaller size and sharp ability to penetrate living organisms at any trophic level. Few studies evaluate the impact of nanoplastics in vivo on the immune system of aquatic organisms, while most of them assessed the impact on indirect markers of immune response such as regulation of gene expression, ROS production or DNA genotoxicity, among others. Moreover, the study of the effects of nanoplastics on aquatic vertebrate species in vivo is still scarce. In this context, we seek to shed light on the underlying effects of polystyrene nanoplastics (PS-NPs) on the immune response in a model fish species (Danio rerio, zebrafish) after an acute exposure, with a combination of in vitro and in vivo experiments. Our results show that PS-NPs (65 nm) are efficiently taken up by zebrafish liver cells, accumulating mainly in lysosomes. Furthermore, the expression of immune genes presents a synergy when cells were simultaneously exposed to PS-NPs, at a low dose and early time point (12 h) and challenged with a viral stimulus (poly(I:C)). Moreover, zebrafish larvae also internalize PS-NPs, accumulating them in the gut and pancreas. However, at concentrations of up to 50 mg l-1 in an acute exposure (48 h), PS-NPs do not interfere with the survival of the larvae after a lethal bacterial challenge (Aeromonas hydrophila). This study addresses the relevant environmental question of whether a living organism exposed to PS-NPs can cope with a real immune threat. We show that, although PS-NPs can induce an immune response, the survival of zebrafish larvae challenged with a bacterial infection after an acute exposure to PS-NP is not decimated with respect to unexposed larvae

Mucosal Immunity and B Cells in Teleosts : Effect of Vaccination and Stress

Fish are subjected to several insults from the environment, which may endanger animal survival. Mucosal surfaces are the first line of defense against these threats, acting as a physical barrier to protect the animal but also functioning as an active immune tissue. Thus, four mucosal-associated lymphoid tissues (MALTs), which lead the immune responses in gut, skin, gills, and nose, have been described in fish. Humoral and cellular immunity, as well as their regulation and the factors that influence the response in these mucosal lymphoid tissues, are still not well known in most fish species. Mucosal B-lymphocytes and immunoglobulins (Igs) are key players in the immune response that takes place in those MALTs. The existence of IgT as a mucosal specialized Ig gives us the opportunity of measuring specific responses after infection or vaccination, a fact that was not possible until recently in most fish species. The vaccination process is influenced by several factors, being stress one of the main stimuli determining the success of the vaccine. Thus, one of the major goals in a vaccination process is to avoid possible situations of stress, which might interfere with fish immune performance. However, interaction between immune and neuroendocrine systems at mucosal tissues is still unknown. In this review, we will summarize the latest findings about B-lymphocytes and Igs in mucosal immunity and the effect of stress and vaccination on B-cell response at mucosal sites. It is important to point out that a limited number of studies have been published regarding stress in mucosa and very few about the influence of stress over mucosal B-lymphocytes