Search results for "seeprakala"

Experimental size-selective harvesting affects behavioral types of a social fish

2019

In most fisheries, larger fish experience substantially higher mortality than smaller fish. Body length, life history, and behavioral traits are often correlated, such that fisheries-induced changes in size or life history can also alter behavioral traits. However, empirical evidence regarding how size-selective harvesting alters the evolution of behavioral traits in exploited stocks is scarce. We used experimental lines of Zebrafish Danio rerio that were exposed to positively size-selective, negatively size-selective, or random harvest over five generations. Our aim was to investigate whether simulated fishing changed the mean personality of the surviving females five generations after ini…

Coinfection outcome in an opportunistic pathogen depends on the inter-strain interactions

2017

Background In nature, organisms are commonly coinfected by two or more parasite strains, which has been shown to influence disease virulence. Yet, the effects of coinfections of environmental opportunistic pathogens on disease outcome are still poorly known, although as host-generalists they are highly likely to participate in coinfections. We asked whether coinfection with conspecific opportunistic strains leads to changes in virulence, and if these changes are associated with bacterial growth or interference competition. We infected zebra fish (Danio rerio) with three geographically and/or temporally distant environmental opportunist Flavobacterium columnare strains in single and in coinf…

The Influence of Infective Dose on the Virulence of a Generalist Pathogen in Rainbow Trout (Oncorhynchus mykiss) and Zebra Fish (Danio rerio)

2015

Pathogen density and genetic diversity fluctuate in the outside-host environment during and between epidemics, affecting disease emergence and the severity and probability of infections. Although the importance of these factors for pathogen virulence and infection probability has been acknowledged, their interactive effects are not well understood. We studied how an infective dose in an environmentally transmitted opportunistic fish pathogen, Flavobacterium columnare, affects its virulence both in rainbow trout, which are frequently infected at fish farms, and in zebra fish, a host that is not naturally infected by F. columnare. We used previously isolated strains of confirmed high and low …

Chemical composition and particle size influence the toxicity of nanoscale plastic debris and their co-occurring benzo(α)pyrene in the model aquatic …

2021

Little is known about how particle chemical composition and size might influence the toxicity of nanoscale plastic debris (NPD) and their co-occurring chemicals. Herein, we investigate the toxicity of 3 × 1010 particles/L polyethylene (PE, 50 nm), polypropylene (PP, 50 nm), polystyrene (PS, 200 and 600 nm), and polyvinyl chloride (PVC, 200 nm) NPD and their co-occurring benzo(a)pyrene (BaP) to Daphnia magna and Danio rerio. During the 21 days of exposure to PE 50 nm and PS 200 nm, the number of broods produced by D. magna decreased compared to other treatments. Exposure to BaP alone did not produce any effects on the reproduction of the daphnids, however, the mixture of BaP with PS (200 or …

Advancing the ecotoxicological relevancy of zebrafish : application of early-juvenile 20dpfZF to assess xenoestrogenicity of environmental chemicals …

2014

The influence of infective dose, nutrient availability and coinfection on virulence of Flavobacterium columnare : implications of intensive aquacultu…

2016

Ecological factors are known to affect disease dynamics and even lead to disease emergence. Especially in opportunistic, environmentally transmitted pathogens, the environment may significantly contribute to pathogen virulence. Intensive farming, including aquaculture, has been suggested to create conditions favouring development of highly virulent pathogens. At Finnish fish farms, epidemics caused by opportunistic Flavobacterium columnare have been constantly increasing in their prevalence and severity since the 1980’s. Yet, factors behind the increased virulence of the pathogen and their mechanisms of action have largely remained unsolved. In this thesis, I explore the effects of infectio…

Ympäristöestrogeeniseoksen yhteisvaikutus 20dpfZF-seeprakalan vitellogeniinigeenin ilmentymiseen

2011

Ihmisten toimesta ympäristöön joutuvien vierasaineiden vaikutukset hormonitoimintaan ovat viime vuosina herättäneet paljon keskustelua. Yksi alan tutkituimmista aihealueista on estrogeenin kaltaisesti vaikuttavien aineiden eli ympäristöestrogeenien aiheuttamat lisääntymis- ja kehityshäiriöt. Estrogeenisiä vaikutuksia voidaan tutkia monella tapaa, alkaen solutason vasteista populaatiokehitykseen. Yksi paljon käytetty molekyylimarkkeri on kalojen vitellogeniinitason mittaus. Vaikka normaalioloissa vain naaraat tuottavat vitellogeniiniä, estrogeenialtistuksen vaikutuksesta myös koiraat ja nuoret yksilöt voivat sitä tuottaa. Tässä opinnäytetyössä tutkittiin kolmen ympäristöestrogeenin, bisfenol…

Effects of perilipin I & V on the phenotype of zebrafish embryos

2012

Tämä Pro Gradu-tutkielma on tehty yhteistyössä Tampereen yliopiston Biolääketieteel- lisen teknologian yksikön kanssa. Tutkimuksen tarkoituksena oli selvittää perilipiinien vaikutusta seeprakalan fenotyyppiin käyttäen tutkimusmenetelminä geenien hiljentämistä ja mikroskopiaa. Geenit säätelevät proteiinien tuotantoa elimistössä. Jokaista proteiinia koodaa geeni, jonka toimintaan puuttumalla voidaan esimerkiksi estää kyseisen proteiinin muodos- tuminen. Morfoliinot ovat oligonukleotideja, joiden avulla voidaan tilapäisesti estää geenien toimintaa. Tässä työssä hiljennettiin morfoliinojen avulla kaksi geeniä seep- rakaloilta: perilipiini 1 ja perilipiini 5. Perilipiinit ovat lipidien varastoit…

Size-selective harvesting fosters adaptations in mating behavior and reproductive allocation, affecting sexual selection in fish

2019

The role of sexual selection in the context of harvest‐induced evolution is poorly understood. However, elevated and trait‐selective harvesting of wild populations may change sexually selected traits, which in turn can affect mate choice and reproduction. We experimentally evaluated the potential for fisheries‐induced evolution of mating behaviour and reproductive allocation in fish. We used an experimental system of zebrafish (Danio rerio) lines exposed to large, small or random (i.e. control) size‐selective mortality. The large‐harvested line represented a treatment simulating the typical case in fisheries where the largest individuals are preferentially harvested. We used a full factoria…