"Nested" cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions

<p>Abstract</p> <p>Background</p> <p>Ecosystem engineers facilitate habitat formation and enhance biodiversity, but when they become invasive, they present a critical threat to native communities because they can drastically alter the receiving habitat. Management of such species thus needs to be a priority, but the poorly resolved taxonomy of many ecosystem engineers represents a major obstacle to correctly identifying them as being either native or introduced. We address this dilemma by studying the sea squirt <it>Pyura stolonifera</it>, an important ecosystem engineer that dominates coastal communities particularly in the southern hemisphere. Using DNA sequence data from four independently evolving loci, we aimed to determine levels of cryptic diversity, the invasive or native status of each regional population, and the most appropriate sampling design for identifying the geographic ranges of each evolutionary unit.</p> <p>Results</p> <p>Extensive sampling in Africa, Australasia and South America revealed the existence of "nested" levels of cryptic diversity, in which at least five distinct species can be further subdivided into smaller-scale genetic lineages. The ranges of several evolutionary units are limited by well-documented biogeographic disjunctions. Evidence for both cryptic native diversity and the existence of invasive populations allows us to considerably refine our view of the native versus introduced status of the evolutionary units within <it>Pyura stolonifera </it>in the different coastal communities they dominate.</p> <p>Conclusions</p> <p>This study illustrates the degree of taxonomic complexity that can exist within widespread species for which there is little taxonomic expertise, and it highlights the challenges involved in distinguishing between indigenous and introduced populations. The fact that multiple genetic lineages can be native to a single geographic region indicates that it is imperative to obtain samples from as many different habitat types and biotic zones as possible when attempting to identify the source region of a putative invader. "Nested" cryptic diversity, and the difficulties in correctly identifying invasive species that arise from it, represent a major challenge for managing biodiversity.</p

Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?

This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench. [Authors]]]> Nanostructures; Toxicity Tests; Ecotoxicology/methods; Guidelines; eng https://serval.unil.ch/resource/serval:BIB_5FCE25CBF6A9.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_5FCE25CBF6A95 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_5FCE25CBF6A95 info:eu-repo/semantics/submittedVersion info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_5FCE8EA1AD9C 2022-02-19T02:22:28Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_5FCE8EA1AD9C Apprendre à suivre une règle : jeux d'alternance et constitution du sujet moral Erard, Y. info:eu-repo/semantics/bookPart incollection 2007 Morale et évolution biologique oai:serval.unil.ch:BIB_5FC219D991AA 2022-02-19T02:22:28Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_5FC219D991AA Réflexion sur la réduction de peine en cas de détention illicite Parein, Loïc info:eu-repo/semantics/article article 2015 Revue de l'avocat, vol. 4, no. 15, pp. 166-170 info:eu-repo/semantics/altIdentifier/pissn/1422-5778 fre https://serval.unil.ch/resource/serval:BIB_5FC219D991AA.P001/REF.pdf info:eu-repo/semantics/publishedVersion info:eu-repo/semantics/restrictedAccess Restricted: indefinite embargo Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_5FC2874DDD0E 2022-02-19T02:22:28Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_5FC2874DDD0E Radial Ultrasound-Assisted Transbronchial Biopsy: A New Diagnostic Approach for Non-Resolving Pulmonary Infiltrates in Neutropenic Hemato-Oncological Patients. info:doi:10.1007/s00408-016-9947-3 info:eu-repo/semantics/altIdentifier/doi/10.1007/s00408-016-9947-3 info:eu-repo/semantics/altIdentifier/pmid/27704258 Bernasconi, M. Casutt, A. Koutsokera, A. Letovanec, I. Tissot, F. Nicod, L.P. Lovis, A. info:eu-repo/semantics/article article 2016-12 Lung, vol. 194, no. 6, pp. 917-921 info:eu-repo/semantics/altIdentifier/eissn/1432-1750 urn:issn:0341-2040 <![CDATA[The role of radial-endobronchial ultrasound (R-EBUS) assisted transbronchial biopsy (TBB) for the diagnosis of peripheral pulmonary lesions is well established. However, no study has addressed its safety and value in hemato-oncological patients presenting with non-resolving infiltrates during persistent febrile neutropenia. To assess safety and feasibility of R-EBUS assisted TBB in severe thrombocytopenic and neutropenic patients. Over a period of 18 months, eight patients were assessed with R-EBUS assisted TBB after adequate platelet transfusion. This technique allowed precise localisation and sampling of the pulmonary lesions in seven of eight patients. In the seven patients, R-EBUS assisted TBB enabled treatment optimization. Invasive fungal infection was diagnosed in four patients, idiopathic acute fibrinous and organising pneumonia in three patients, and a granulomatous inflammation of undetermined origin in one patient. Importantly, no complications, such as bleeding, were observed. R-EBUS assisted TBB is a promising and safe procedure for the evaluation of nonresolving pulmonary infiltrates in febrile neutropenic hemato-oncological patients