The discovery of male Caligus brevicaudatus Scott, 1901 (Copepoda: Caligidae) parasitic on tub gurnard, Chelidonichthys lucerna (Linnaeus) from the eastern Mediterranean

© Institute of Parasitology, Biology Centre CAS. Folia Parasitologica is an open access journal since 2015, this article is published under the terms of a Creative Commons License (http://creativecommons.org/licenses/by/4.0/). The file attached is the published version of the article

Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution

Background: The Caligidae is a family of parasitic copepods containing over 30 recognised genera. They are\ud commercially important parasites as they cause disease in numerous finfish aquaculture facilities globally.\ud Morphological features are used to distinguish between the genera and Pseudocaligus has traditionally been\ud differentiated from Caligus solely by the presence of a much reduced form of the fourth thoracic leg. Currently\ud there are numerous DNA sequences available for Caligus spp. but only the type species, Pseudocaligus brevipedis,\ud has molecular data available, so systematic studies using molecular phylogenetic analyses have been limited.\ud Methods: Three gene regions, SSU rDNA, 16S and CO1, for Pseudocaligus fugu from puffer fish from Japan and\ud Pseudocaligus uniartus from rabbit fish from Indonesia are sequenced and molecular phylogenetic analyses\ud performed in order to infer phylogenetic relationships between Pseudocaligus and other caligid copepods.\ud Results: The analysis revealed that there was no discrete grouping of Pseudocaligus spp. and that they had a\ud polyphyletic distribution within Caligus taxa. Pseudocaligus fugu grouped with Caligus elongatus and contained a\ud unique synapomorphy in the SSU rDNA region only seen in members of that clade. Pseudocaligus uniartus\ud formed a well-supported group, in the SSU rDNA analyses, with a Caligus sp. that also infects rabbit fish, but was\ud unresolved in the other analyses. Pseudocaligus brevipedis consistently and robustly grouped with Caligus curtus\ud and C. centrodonti in all analyses. The majority of Lepeophtheirus spp. form a monophyletic sister group to the\ud Caligus clade; however, L. natalensis is unresolved in all analyses and does not form part of the main\ud Lepeophtheirus clade.\ud Conclusions: These findings do not support the morphological-based distinction between Pseudocaligus and Caligus,\ud suggesting that the reduced fourth leg is a feature that has evolved on multiple occasions throughout caligid evolution.\ud Congruent molecular phylogenetic data support groupings based on the presence of morphological features, such as\ud lunules, geography and host fish type rather than appendage morphology. Therefore, we support the synonymy of\ud Pseudocaligus with Caligus

The use of prevalence as a measure of lice burden: a case study of Lepeophtheirus salmonis on Scottish Atlantic salmon, Salmo salar L., farms

This study investigates the benefits of using prevalence as a summary measure of sea lice infestation on farmed Atlantic salmon, Salmo salar L. Aspects such as sampling effort, the relationship between abundance and prevalence arising from the negative binomial distribution, and how this relationship can be used to indicate the degree of aggregation of lice on a site at a given time point are discussed. As a case study, data were drawn from over 50 commercial Atlantic salmon farms on the west coast of Scotland between 2002 and 2006. Descriptive statistics and formal analysis using a linear modelling technique identified significant variations in sea lice prevalence across year class, region and season. Supporting evidence of a functional relationship between prevalence and abundance of sea lice is provided, which is explained through the negative binomial distribution

Changes in epidemiological patterns of sea lice infestation on farmed Atlantic salmon, Salmo salar L., in Scotland between 1996 and 2006

Analyses of a unique database containing sea lice records over an 11 year period provide evidence of changing infestation patterns in Scotland. The data, collected from more than 50 commercial Atlantic salmon farms, indicate that both species of sea lice commonly found in Scotland, Lepeophtheirus salmonis and Caligus elongatus, have declined on farms over the past decade. Reductions for both species have been particularly marked since 2001 when more effective veterinary medicines became available. Treatment data were also available in the database and these show a growing trend towards the use of the in feed medication emamectin benzoate (Slice), particularly in the first year of the salmon production cycle. However, this trend to wards single product use has not been sustained in 2006, the latest year for which data are available. There is some evidence of region to region variation within Scotland with the Western Isles experiencing higher levels of infestation. However, compared to the levels observed between 1996 and 2000, all regions have benefited from reduced lice infestation, with the overall pattern showing a particular reduction in the second and third quarters of the second year of production

Description of the male of Caligus hilase Shaw (Copepoda, Caligidae)

Caligus hil.rae Shen, 1957, is unique in the possession of a comparatively very long four-segmented abdomen, long anal laminae which are nearly three times as long as broad and in the absence of the sternal fork

Identificación de blancos terapéuticos putativos en Caligus rogercresseyi utilizando bases de datos de transcriptómica del parásito

86 p.Caligus rogercresseyi es un ectoparásito que afecta en gran medida la producción de salmónidos en Chile. Se estima que las pérdidas directas e indirectas asociadas a Caligus en el año 2013 fueron de alrededor de US$80 millones. De la misma manera, los costos para la industria desde los primeros brotes de Caligus resistente a los medicamentos en 2007 ascendieron a US$ 700 millones, lo que indica la gran importancia de estudiar mecanismos de control de este parásito. En la actualidad se ha experimentado un evidente desarrollo de resistencias de C. rogercresseyi frente a los distintos tratamientos aplicados. Dentro de los principales factores que influyeron en esta pérdida de eficacia (resistencia) se menciona el uso exclusivo y continuado del producto por más de 7 años. Para este trabajo contamos con un set de datos transcriptómicos del parasito, es decir, secuencias obtenidas a partir de RNA. Las ventajas que tiene analizar el RNA o transcriptoma de un organismo, es el poder identificar cambios de expresión génica en determinado momento celular de un tratamiento, con respecto a un control, es decir, obtenemos una imagen temporal del panorama celular asociado a los RNAs, con respecto al panorama del tratamiento, haciendo comparables y evaluables los niveles de expresión en ambas condiciones mediante algoritmos estadísticos. En este contexto, la bioinformática juega un papel fundamental, como una disciplina integrativa que se ha convertido en un componente intrínseco en esta nueva fase de estudios moleculares a gran escala, pues provee herramientas para el manejo, análisis y manipulación de grandes cantidades de datos. Durante los últimos años, se ha logrado obtener información del RNA de variados organismos, los cuales son sujetos de investigación. Es por esto que técnicas de secuenciación de RNA (bajo el protocolo de secuenciación RNA-seq) han demostrado ser una herramienta de gran alcance y con una gama muy diversa de aplicaciones. Con respecto a éste trabajo de memoria de título, el objetivo principal se basa en identificar secuencias aminoacídicas deducidas, asociadas a posibles proteínas o péptidos vinculados con resistencia farmacológica y/o como blancos terapéuticos putativos a través del análisis de las bases de datos transcriptómicas de Caligus rogercresseyi. Para lograr lo anterior, se realizó un análisis de las bases de datos transcriptómicas de Caligus rogercresseyi a partir de un ensamble de novo del transcriptoma del parásito, para luego lograr identificar a través de expresión diferencial los distintos niveles de expresión existentes con tratamientos de Emamectina y Deltametrina en C.rogercresseyi. Se utilizó un protocolo de RNA-seq, en conjunto con otras herramientas bioinformáticas, con las cuales se buscó encontrar blancos terapéuticos putativos, que permitan desarrollar futuros estudios para combatir con éxito a este parásito y, de esta manera a largo plazo, lograr disminuir de las pérdidas económicas causadas por Caligus. Y desde otra perspectiva, que en ningún caso es menos importante, la generación de este conocimiento posibilitará contribuir en una posible disminución de la contaminación ambiental asociada a los tratamientos químicos, como los realizados hoy en día./ ABSTRACT: Caligus rogercresseyi is an ectoparasite that greatly affects the production of salmonids in Chile. It is estimated that the direct and indirect losses associated with sea lice in 2013 were about US $80 millions. Similarly, the costs for the industry since the first outbreaks of drug-resistant sea lice in 2007 amounted to US$ 700 million, which indicates the great importance of studying mechanisms controlling this pest. Today it has experienced an obvious development of resistance of C. rogercresseyi against the various treatments applied. Among the main factors influencing this efficiency loss (resistance) mentioned the exclusive and continuous use of the product for more than 7 years.For this study we have a set of the parasite transcriptome data, that is to say sequences obtained from RNA. The advantages analyze the RNA or transcriptome of an organism, in order to identify gene expression changes in certain cells during a treatment, with respect to control, that is to say, obtain a temporary image cell panorama of associated RNAs, with respect to the treatment panorama, making comparable and evaluable expression levels in both conditions using statistical algorithms. In this context, bioinformatics plays a key role as an integrative discipline that has become an intrinsic component in this new phase of molecular-scale studies, it provides tools for operation, analysis and handling of large amounts of data. In recent years, it has been possible to obtain information of various organisms RNA, which are subject to research. That is why RNA sequencing techniques (under the protocol sequencing RNA-seq) have proven to be a powerful tool with a very diverse range of applications. With respect to this thesis, the main objective is based on identifying amino acid sequences deduced, associated with possible proteins or peptides associated with drug resistance and / or as therapeutic targets putative through the analysis of the basis of transcriptomic data Caligus rogercresseyi. To achieve this, an analysis of the basis of transcriptomic data Caligus rogercresseyi was performed from an ensemble de novo transcriptome parasite, and then be able to identify through differential expressions, different levels of existing expression treatments Emamectin and deltamethrin in C. rogercresseyi. IX A protocol of RNA-seq was used in conjunction with other bioinformatics tools, with which they seek to find putative therapeutic targets, in order to develop future studies to successfully combat this parasite and thus long-term, achieve the decrease of economic losses caused by sea lice. And from another perspective, that in no case is less important, the generation of this knowledge will enable a contribution to a possible reduction of environmental pollution associated with chemical treatments, such as those made today

Parasites of cage cultured European seabass <i>Dicentrarchus Labrax</i> and gilthead seabream <i>Sparus aurata</i> from Sardinia (western Mediterranean): first results

European seabass Dicentrarchus labrax and gilthead seabream Sparus aurata are the most important marine finfish species intensively cultured in the Mediterranean. Many factors influenced the rapid increase in the production of these species in the last two decades. One of the most important factors is the great development and diffusion of sea-cage culture, because some of the parasite species has become a serious threat to cage-reared fish in other Mediterranean localities