800 research outputs found

    New species from the deep Pacific suggest that carnivorous sponges date back to the Early Jurassic

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    Some deep-sea poecilosclerid sponges (Porifera) have developed a carnivorous feeding habit that is very surprising in sponges^1^. As shown by the typical morphology of their spicules, they most probably evolved from "normal sponges" under the difficult conditions of a deep-sea environment. Such evolution, which implies the loss of the diagnostic character of the phylum Porifera, i.e. a filter feeding habit through a complex aquiferous system, should be of great interest in the understanding of the origin of metazoans. Some scenarios, based on the hypothesis of the paraphyly of Porifera, allege that metazoans could derive from a sponge filter-feeding body plan. A difficulty, however, is to imagine the transition from a sponge grade of organization to other organization plans^2^. Carnivorous sponges demonstrate that a functional, non filter-feeding animal may derive from a conventional sponge body plan, albeit nothing is known of the age of this evolution. Here we report that newly discovered species of _Chondrocladia_ from the deep Pacific display special spicules that were previously recorded only as isolated spicules from sediment dating back to the Early Jurassic and Miocene periods. This suggests that the evolution of carnivorous sponges from filter-feeding poecilosclerid demosponges could date back at least from the Early Mesozoic

    Sponges (Porifera) In Submarine Caves

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    Sponges (phylum Porifera) have the most simple and probably the most ancient body plan of the multicellular animals. They are, however, very successful in most benthic ecosystems. They are dominant in submarine caves, where their study has provided unexpected results. Submarine caves share several ecological features with deep-sea habitats. The communities living in these habitats depend on allochthonous organic input, and some bathyal species are able to colonize the darkest parts of littoral caves. Some examples will be given, including calcified sponges,«living fossils» of ancient reef builders. Faunal and environmental similarities, however, are limited by the obvious differences in pressure, temperature, habitat size, and by the dispersal abilities of deep water organisms. A recently discovered Mediterranean cave more closely approximates deep-sea conditions, due to the entrapment of a cold water mass resulting in stable temperature conditions throughout the year. Easily accessible to scuba divers, this «bathyal island» in the littoral zone is a natural mesocosm of the deep Mediterranean which offers exceptional opportunities for deep-sea biology. Preliminary results have already provided unexpected insights, which are illustrated. A large population of Oopsacas minuta, a representative of the bathyo-abyssal hexactinellid sponges, reproduces here year round - making possible the first observations of larval behaviour and ultrastructure to be carried out on this phylogenetically important group of invertebrates, and opening up the poorly known area of larval ecology of these deep-sea sponges. The presence of a species of the deepest known genus of sponges, Asbestopluma (8 840 m in the Central Pacific) is a fascinating opportunity to investigate the biology of the strange deep-sea cladorhizid sponges, which may live in the most oligotrophic abyssal basins. A highly unexpected result is that they are non-filter-feeding sponges with a carnivorous feeding habit. They capture and digest small crustaceans by means of filaments provided with minute hook-shaped spicules. The biology and peculiarities of this carnivorous sponge are illustrated by a video

    A subset of precise UML for Model-based Testing

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    This paper presents an original model-based testing approach that takes a UML behavioural view of the system under test and automatically generates test cases and executable test scripts according to model coverage criteria. This approach is embedded in the LEIRIOS Test Designer tool and is currently deployed in domains such as Enterprise IT and electronic transaction applications. This model-based testing approach makes it possible to automatically produce the traceability matrix from requirements to test cases as part of the test generation process. This paper defines the subset of UML used for model-based testing and illustrates it using a small example

    Esponjas lithistidas de cuevas submarinas en el Mediterráneo: su taxonomía y relaciones

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    Several lithistid sponges are described from Mediterranean caves occurring in the northwestern and Adriatic basins. In the Corallistidae, Neoschrammeniella bowerbanki and Neophrissospongia nolitangere are recorded for the first time from the Mediterranean, whereas Neophrissospongia radjae n. sp. and Neophrissospongia endoumensis n. sp. are described as new. In the Theonellidae, the common sponge previously identified as Discodermia polydiscus is described as Discodermia polymorpha n. sp. Fossil specimens from the 3PP cave are tentatively attributed to Neoschrammeniella bowerbanki. The distribution and affinities of this lithistid fauna are discussed.Se describen varias esponjas lithistidas procedentes de cuevas del noroeste del mar Mediterráneo y de las cuencas del mar Adriático. Dentro de las esponjas incluidas en la familia Corallistidae, Neoschrammeniella bowerbanki y Neophrissospongia nolitangere, se registran por primera vez en el Mediterráneo y Neophrissospongia radjae n. sp. y Neophrissospongia endoumensis n. sp. se describen como nuevas especies. Dentro de la Familia Theonellidae, la esponja común, que hasta la fecha se había identificado como Discodermia polydiscus se describe como Discodermia polymorpha n. sp. Ejemplares fósiles de la cueva de los 3PP se asignan provisionalmente a Neoschrammeniella bowerbanki. Se discute la distribución y afinidades de la fauna de las lithistidas

    Determination of Listeria monocytogenes numbers at less than 10 cfu/g

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    peer-reviewedListeria monocytogenes is a foodborne pathogen that causes a relatively rare foodborne disease called listeriosis, with a high mortality rate of 20%-30% and an undefined dose response. Current European Union regulations permit up to 100 colony-forming units (cfu)/g in food at the end of its shelf life, where the food has been shown not to support the growth of this pathogenic bacterium. Therefore, enumeration of L. monocytogenes at low numbers in food is important. The objective of this study was to reduce the detection limit of L. monocytogenes in food by a factor of 10. The International Organisation for Standardisation (ISO) 11290-2 method for enumeration of L. monocytogenes in food recommends spreading 0.1 mL of a 1:10 dilution of the food on the surface of an agar plate (detection limit 100 cfu/g), or 1.0 mL spread in equal parts on the surface of three agar plates (detection limit: 10 cfu/g). The pour-plate method (using 1 or 10 mL of an appropriate dilution) was compared to the spread-plate method using the ISO-approved chromogenic medium Agar Listeria according to Ottaviani and Agosti (ALOA). Using the pour-plate method, the colony morphology and halo formation were similar to the spread-plate method from pure cultures and inoculated foods. Using the pour-plate method in a 140 mm Petri dish, 10 mL of a 1:10 dilution of food allowed determination of numbers as low as 1 cfu/g. Applying this method, L. monocytogenes in naturally contaminated food samples were enumerated at numbers as low as 1-9 cfu/g.This work was supported by The Irish Department of Agriculture, Food and the Marine under the Food Institutional Research Measure, project 11/F/008, and by the Dairy Processing Technology Centre, supported by Enterprise Ireland and the Irish Dairy Industry, project number TC 2014 0016

    Origine du manganèse de la nappe alluviale de Beaucaire (Gard, France) Essai de démanganisation in situ (procédé Vyredox)

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    L'origine et le mécanisme de l'augmentation de la concentration en manganèse dans l'eau de la nappe phréatique de Beaucaire ont été recherchés afin d'orienter le choix d'un procédé de démanganisation adapté aux conditions du site.L'aquifère est caractérisé par son déficit en oxygène et par la présence de dépôts d'oxyde de manganèse (Mn(IV)) sur les sédiments. Dans ces conditions la microflore utilise les oxydes de manganèse conne accepteur final d'électrons (démontré dans les expériences in vitro) et le manganèse réduit passe alors en solution.Lors des essais d'application du procédé Vyredox le potentiel d'oxydoréduction de la nappe augmente et la concentration en manganèse dissous diminue. Rien n'indique une précipitation du manganèse et donc un colmatage à la périphérie de la partie oxygénée de la nappe.The origin and the mechanism of the increase of the dissolved manganese concentrations have been investigated to choose a system of demanganization well fitted b the site conditions.The aquifer characteristics are a depletion of the dissolved oxygen amount and deposits of manganese oxides (Mn(IV)) on the detriments. Under these conditions the microflora utilizes these manganese oxides as a final electron acceptor (as demonstrated by in vitro experiments) and the solubilization of manganese takes place.The field application of the Vyredox system increases the redox potential of the groundwater and the manganese concentration decreases. Nothing indicates that manganese precipitation and consequently warping of the water table takes place at the periphery of the oxygenated part of the aquifer

    Améliorer la connaissance du patrimoine en France pour une gestion durable du patrimoine des réseaux d'eau potable

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    IWA World Water Congress & Exhibition, Tokyo, JPN, 16-/09/2018 - 21/09/2018International audienceWith the aim of improving the implementation and evaluation of public policy in France relating to sustainable drinking water asset management (regulation at national level and subsidies at watershed level) the French Ministry of Ecology asked Irstea, a state research body, to create an ongoing system to manage technical and financial knowledge relating to drinking water network assets. In this study we develop a statistical approach to model pipe length by category, based on the geographical characteristics of the territory in which they are installed. Multivariate models including road length have been found to be pertinent. This technical analysis is accompanied by a study of asset values and renewal costs, based on a typology of water suppliers and an examination of economic and financial ratios. A number of disparities between territories are highlighted

    Un Spongiaire Sphinctozoaire colonial apparenté aux constructeurs de récifs triasiques survivant dans le bathyal de Nouvelle-Calédonie

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    Un second représentant actuel des Sphinctozoaires, importants constructeurs de récifs au Permo-Trias, a été découvert dans la zone bathyale de la NouvelleCalédonie. Contrairement au survivant déjà connu, #Valecetia crypta$, il a conservé le mode de croissance colonial et les capacités constructrices de ses analogues fossiles. Sa croissance est bien plus lente que celle des coraux récifaux actuels. La base d'une construction de 10 cm d'épaisseur a été datée de 700 ans. (Résumé d'auteur

    The genus <i>Batzella</i>: a chemosystematic problem

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    Biogenetically unrelated cyclic guanidine alkaloids and pyrroloquinoline alkaloids have been reported from sponges assigned to the genus Batzella. These sponges have been assigned to this genus because of their possession of a simple complement of thin strongyles in irregular plumoreticulate arrangement. Cyclic guanidine alkaloids were first reported from an alleged axinellid species from the Caribbean, Ptilocaulis aff. P. spiculifer, and subsequently from a second Carribean specimen identified as Ptilocaulis spiculifer and at the same time from a Red Sea poecilosclerid, Hemimycale sp. Closely related compounds were described from a Caribbean specimen identified as Batzella sp. and also from the poecilosclerids Crambe crambe (Mediterranean) and Monanchora arbuscula (Brazil). Isobatzellins (pyrroloquinoline alkaloids) were reported from a black deep-water species from the Bahamas identified as Batzella sp. Chemically related pyrroloquinoline alkaloids were found in Pacific representatives of the fistular poecilosclerid genus Zyzzya, the hadromerid genus Latrunculia and the ?haplosclerid genus Prianos. Most of the voucher specimens involved in this puzzle were re-examined and several conclusions can be drawn: when inspected closely it appears, that the cyclic guanidine alkaloids are produced by sponges containing anisostrongyles, often in two categories, a thicker and a thinner one. Monanchora arbuscula, which has been recently discovered to produce these compounds, has monactinal spicules differentiated into a thinner subtylostyle and a thicker (tylo-) style, but many specimens have anisostrongylote modifications. Microscleres in Monanchora can be absent or very rare. By association, all the sponges from which cyclic guanidine alkaloids are known may be united in one family, possibly in a single wider defined genus Monanchora. However, further relationships with Crambe need to be studied. Both have cyclic guanidine alkaloids, both have megascleres of very variable shapes and thickness, differentiated mostly into two overlapping categories, microscleres and other additional spicules are often rare or absent. Relationships with the type of Hemimycale, viz. H. columella remain obscure, but in view of the much larger spicules of that species and the intricate ectosomal specialization (lacking in the above mentioned specimens) it is possible that similarities between the Red Sea Hemimycale and the European species are the product of parallel evolution. The strongyles of sponges producing pyrroloquinoline alkaloids are perfect isostrongyles and in the ectosome these are arranged in a definite ectosomal tangential crust. A good proportion of these strongyles have a faint spination on the apices. Assignment of these sponges to Batzella rest on the properties of its type species Batzella inops. Examination of a type spicule slide of that species did not solve that question, but until further notice Batzella may be used for the deep-water material. A further unsolved problem that remains is the phylogenetic relationships of Batzella with Zyzzya and Latrunculia. The likelyhoods of possible causes for this distribution of compounds are discussed
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