80 research outputs found
Parasite-induced aggression and impaired contest ability in a fish host
Abstract
Background
Success of trophically transmitted parasites depends to a great extent on their ability to manipulate their intermediate hosts in a way that makes them easier prey for target hosts. Parasite-induced behavioural changes are the most spectacular and diverse examples of manipulation. Most of the studies have been focused on individual behaviour of hosts including fish. We suggest that agonistic interactions and territoriality in fish hosts may affect their vulnerability to predators and thus the transmission efficiency of trophically transmitted parasites. The parasite Diplostomum spathaceum (Trematoda) and juvenile rainbow trout, Oncorhynchus mykiss, were used to study whether infection can alter aggression rates and territorial behaviour of intermediate fish hosts.
Results
The changes in behaviour of rainbow trout, Oncorhynchus mykiss, infected with an eye fluke Diplostomum spathaceum (Trematoda), was monitored over the course of an experimental infection for 1.5 months. At the beginning of their development, not yet infective D. spathaceum metacercariae decreased the aggressiveness of rainbow trout. By the time that metacercariae were fully infective to their definitive hosts, the aggressiveness increased and exceeded that of control fish. Despite the increased aggressiveness, the experimentally infected fish lost contests for a territory (dark parts of the bottom) against the control fish.
Conclusions
The results obtained indicate that the parasitized fish pay the cost of aggressiveness without the benefit of acquiring a territory that would provide them with better protection against predators. This behaviour should increase transmission of the parasite as expected by the parasite manipulation hypothesis
Maternal effects in vulnerability to eye-parasites and correlations between behavior and parasitism in juvenile Arctic charr
Hatchery-reared fish show high mortalities after release to the wild environment. Explanations for this include potentially predetermined genetics, behavioral, and physiological acclimation to fish farm environments, and increased vulnerability to predation and parasitism in the wild. We studied vulnerability to Diplostomum spp. parasites (load of eye flukes in the lenses), immune defense (relative spleen size) and antipredator behaviors (approaches toward predator odor, freezing, and swimming activity) in hatchery-reared juvenile Arctic charr (Salvelinus alpinus) using a nested mating design. Fish were exposed to eye-fluke larvae via the incoming water at the hatchery. Fish size was positively associated with parasite load, but we did not find any relationship between relative spleen size and parasitism. The offspring of different females showed significant variation in their parasite load within sires, implying a dam effect in the vulnerability to parasites. However, the family background did not have any effect on spleen size. In the mean sire level over dams, the fish from the bolder (actively swimming) families in the predator trials suffered higher loads of eye flukes than those from more cautiously behaving families. Thus, the results indicate potentially maternally inherited differences in vulnerability to eye-fluke parasites, and that the vulnerability to parasites and behavioral activity are positively associated with each other at the sire level. This could lead to artificial and unintentional selection for increased vulnerability to both parasitism and predation if these traits are favored in fish farm environments.Peer reviewe
MTDATA and the prediction of phase equilibria in oxide systems : 30 years of industrial collaboration
This paper gives an introduction to MTDATA, Phase Equilibrium Software from the National Physical Laboratory (NPL), and describes the latest advances in the development of a comprehensive database of thermodynamic parameters to underpin calculations of phase equilibria in large oxide, sulfide, and fluoride systems of industrial interest. The database, MTOX, has been developed over a period of thirty years based upon modeling work at NPL and funded by industrial partners in a project co-ordinated by Mineral Industry Research Organisation. Applications drawn from the fields of modern copper scrap smelting, high-temperature behavior of basic oxygen steelmaking slags, flash smelting of nickel, electric furnace smelting of ilmenite, and production of pure TiO2via a low-temperature molten salt route are discussed along with calculations to assess the impact of impurities on the uncertainty of fixed points used to realize the SI unit of temperature, the kelvin
Effect of resource availability on evolution of virulence and competition in an environmentally transmitted pathogen
Understanding ecological and epidemiological factors driving pathogen evolution in contemporary time scales is a major challenge in modern health management. Pathogens that replicate outside the hosts are subject to selection imposed by ambient environmental conditions. Increased nutrient levels could increase pathogen virulence by pre-adapting for efficient use of resources upon contact to a nutrient rich host or by favouring transmission of fast-growing virulent strains. We measured changes in virulence and competition in Flavobacterium columnare, a bacterial pathogen of freshwater fish, under high and low nutrient levels. To test competition between strains in genotype mixtures, we developed a quantitative real-time PCR assay. We found that a virulent strain maintained its virulence and outcompeted less virulent strains independent of the nutrient level and resource renewal rate while a less virulent strain further lost virulence in chemostats under low nutrient level and over long-term serial culture under high nutrient level. Our results suggest that increased outside-host nutrient levels might maintain virulence in less virulent strains and increase their contribution to epidemics in aquaculture. The results highlight a need to further explore the role of resource in the outside-host environment in maintaining strain diversity and driving evolution of virulence among environmentally growing pathogens.Peer reviewe
MTDATA and the Prediction of Phase Equilibria in Oxide Systems: 30 Years of Industrial Collaboration
Captive breeding of European freshwater mussels as aconservation tool: A review
1. Freshwater mussels are declining throughout their range. Their importantecological functions along with insufficient levels of natural recruitment haveprompted captive breeding for population augmentation and questions about the usefulness and applicability of such measures. 2. This article reviews the current state of captive breeding and rearing programmes for freshwater mussels in Europe. It considers the various species, strategies, andtechniques of propagation, as well as the different levels of effort requiredaccording to rearing method, highlighting the key factors of success. 3. Within the last 30 years, 46 breeding activities in 16 European countries have been reported, mainly of Margaritifera margaritifera and Unio crassus. Some facilities propagate species that are in a very critical situation, such as Pseudunio auricularius, Unio mancus, and Unio ravoisieri, or multiple species concurrently. Insome streams, the number of released captive-bred mussels already exceeds the size of the remaining natural population. 4. Rearing efforts range from highly intensive laboratory incubation to lowerintensity methods using in-river mussel cages or silos. Most breeding efforts are funded by national and EU LIFE(+) grants, are well documented, and consider the genetic integrity of the propagated mussels. Limited long-term funding perspectives, the availability of experienced staff, water quality, and feeding/survival during early life stages are seen as the most important challenges. 5. Successful captive breeding programmes need to be combined with restoration ofthe habitats into which the mussels are released. This work will benefit from anevidence-based approach, knowledge exchange among facilities, and an overall breeding strategy comprising multiple countries and conservation units. aquaculture, captive breeding, conservation translocation, freshwater mussel culturing, Margaritifera margaritifera, propagation, reintroduction, Unio crassusCaptive breeding of European freshwater mussels as aconservation tool: A reviewpublishedVersio
Research priorities for freshwater mussel conservation assessment
Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions.NF-R was supported by a post-doctoral fellowship (Xunta de Galicia Plan I2C 2017-2020, 09.40.561B.444.0) from the government of the autonomous community of Galicia. BY was supported by the Ministry of Science and Higher Education (no. 0409-2016-0022). DLS was supported by the G. E. Hutchinson Chair at the Cary Institute of Ecosystem Studies. AO was supported by the Russian Foundation for Basic Research (no. 17-44-290016). SV was funded by European Investment Funds by FEDER/COMPETE/POCI- Operacional Competitiveness and Internacionalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT-Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013. NF-R is very grateful to the University of Oklahoma Biological Survey for providing space to work in the U.S. and especially to Vaughn Lab members. Authors are very grateful to Akimasa Hattori, Allan K. Smith, Andrew Roberts, Daniel Graf, David Stagliano, David T. Zanatta, Dirk Van Damme, Ekaterina Konopleva, Emilie Blevins, Ethan Nedeau, Frankie Thielen, Gregory Cope, Heinrich Vicentini, Hugh Jones, Htilya Sereflisan, Ilya Vikhrev, John Pfeiffer, Karen Mock, Mary Seddon, Katharina Stockl, Katarzyna Zajac, Kengo Ito, Marie Capoulade, Marko Kangas, Michael Lange, Mike Davis, Pirkko-Liisa Luhta, Sarina Jepsen, Somsak Panha, Stephen McMurray, G. Thomas Watters, Wendell R. Haag, and Yoko Inui for their valuable contribution in the initial selection and description of extrinsic and intrinsic factors. We also wish to thank Dr. Amanda Bates, Chase Smith, and two anonymous reviewers for comments on earlier drafts of this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government
Integrative phylogenetic, phylogeographic and morphological characterisation of the Unio crassus species complex reveals cryptic diversity with important conservation implications
The global decline of freshwater mussels and their crucial ecological services highlight the need to understand their phylogeny, phylogeography and patterns of genetic diversity to guide conservation efforts. Such knowledge is urgently needed for Unio crassus, a highly imperilled species originally widespread throughout Europe and southwest Asia. Recent studies have resurrected several species from synonymy based on mitochondrial data, revealing U. crassus to be a complex of cryptic species. To address long-standing taxonomic uncertainties hindering effective conservation, we integrate morphometric, phylogenetic, and phylogeographic analyses to examine species diversity within the U. crassus complex across its entire range. Phylogenetic analyses were performed using cytochrome c oxidase subunit I (815 specimens from 182 populations) and, for selected specimens, whole mitogenome sequences and Anchored Hybrid Enrichment (AHE) data on ∼ 600 nuclear loci. Mito-nuclear discordance was detected, consistent with mitochondrial DNA gene flow between some species during the Pliocene and Pleistocene. Fossil-calibrated phylogenies based on AHE data support a Mediterranean origin for the U. crassus complex in the Early Miocene. The results of our integrative approach support 12 species in the group: the previously recognised Unio bruguierianus, Unio carneus, Unio crassus, Unio damascensis, Unio ionicus, Unio sesirmensis, and Unio tumidiformis, and the reinstatement of five nominal taxa: Unio desectus stat. rev., Unio gontierii stat. rev., Unio mardinensis stat. rev., Unio nanus stat. rev., and Unio vicarius stat. rev. Morphometric analyses of shell contours reveal important morphospace overlaps among these species, highlighting cryptic, but geographically structured, diversity. The distribution, taxonomy, phylogeography, and conservation of each species are succinctly described.We thank Ana-Maria Benedek, Monica Sîrbu and Jouni Leinikki for
their assistance with the fieldwork, and to Jeroen Goud, Sankurie Pye,
Fiona Ware, Emily Mitchell, and Aleksandra Skawina for their assistance
with the taxonomic investigation. We would also like to thank the editor,
Dr. Guillermo Ortí, and two anonymous reviewers for their time and
effort in reviewing our manuscript and for their insightful comments and
valuable improvements to our work. This publication is based upon
work from COST Action CA18239: CONFREMU - Conservation of
freshwater mussels: a pan-European approach, supported by COST
(European Cooperation in Science and Technology), including STSMs,
the interaction of the authors and the writing of the paper. This work
was supported by the project ConBiomics: The Missing Approach for the Conservation of Freshwater Bivalves Project No. POCI-01-0145-FEDER-030286, co-financed by FEDER through POCI and by FCT - Fundaç˜ao
para a Ciˆencia e a Tecnologia, through national funds. Strategic funding
UIDB/04423/2020 and UIDP/04423/2020 was provided by FCT. FCT
also supported DVG (2020.03848.CEECIND), EF (CEECINST/00027/
2021/CP2789/CT0003) and MLL (2020.03608.CEECIND). INB, AVK
and IVV were supported by the Russian Science Foundation under grants
(19-14-00066-P), (21-17-00126) and (21-74-10130) respectively. BVB
acknowledges the bioinformatics platform of UMR 8198 for the
computing resources to perform time-calibrated phylogenetic analyses;
this platform is in part funded by CPER research project CLIMIBIO
through the French Minist`ere de l’Enseignement Sup´erieur et de la
Recherche, the Agence Nationale de la Recherche, the European Fund
for Regional Development (FEDER) and the region Hauts-de-France
(HdF). Support to KD came from the Czech Science Foundation
(19–05510S). TT and MT were supported by the National Science Fund
of Bulgaria under the project ‘Conservation of freshwater mussels on the
Balkan Peninsula’ (KP-06-COST-9/20.07.2022). Any use of trade, firm,
or product names is for descriptive purposes only and does not imply
endorsement by the United States Government.info:eu-repo/semantics/publishedVersio
Tilaus-toimitusketjun prosessikuvaus : Levypyörä Oy
Tässä opinnäytetyössä käsitellään Levypyörä Oy:n pyöränvalmistuksen nykytilanteen selvitystä ja tilaus-toimitusketjun prosessikuvausta. Levypyörä Oy halusi selvittää pyörän valmistuksen tuotannon nykytilanteen ja tuotannonohjaustavat. Haastattelujen pohjalta laadittiin prosessikuvaus tilaus-toimitusketjusta.
Opinnäytetyön teoriaosassa käydään läpi eri toiminnanohjauksen periaatteita ja järjestelmiä sekä tuotannonohjauksen tuotantomuotoja ja tuotannonsuunnitteluperiaatteita. Teoriaa kerättiin nykytilan määrityksen mukaan. Teorian avulla saatiin jonkinlainen kuva erilaisista toiminnanohjausmalleista, joita sovelettiin sittemmin käytännön osiossa.
Käytännön osiossa seurattiin tuotannontoimintaa ja haastateltiin tuotannon eri työvaiheissa toimivia työntekijöitä. Tuotannon selvittämisen jälkeen kuvattiin tuotteiden työnkulku eri kaavioiden avulla sekä tehtiin tilaus-toimitusketjun prosessikuvaus. Prosessikuvauksen ja teorian pohjalta selvitettiin mahdollisia ongelmakohtia, joihin annettiin lopuksi kehitysehdotuksia.
Nykytilamäärityksen ja prosessikuvauksen avulla saatiin lisätietoa tilaus-toimitusketjussa jo toimivista ja kehitettävistä asioista. Tämän opinnäytetyön pohjalta Levypyörä Oy:n menettelytapaohje päivitetään.The purpose of this thesis was to describe the present state of wheel manufacturing at Levypyörä Oy and make a description of the supply chain process. Levypyörä Oy wanted to know how their wheel production was working nowadays and how production was controlled. The process description of the supply chain was based on interviews.
The theoretical part of the thesis deals with the principles of production control and systems, as well as production methods and production planning. Theoretical data was collected during the present state analysis. With the help of the theory it was possible to get some kind of picture how production should be controlled.
The practical part of the thesis was made by observing the production process and interviewing employees. After the analysis of the production, I work flowcharts and a process description was made about the supply chain. The process description and the theory part helped to find some problem points in production and give some development ideas in the end.
The present state analysis and process description gave the company more information about things that worked well and what things should be developed. The thesis will also be the foundation for updating the procedural instructions of Levypyörä Oy
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