Relating genotoxicity to DNA repair and reproductive success in zebrafish (Danio rerio) exposed to environmental toxicants

The potential for environmental toxicants to cause genetic damage (genotoxicity) in organisms is a prominent concern because effects on DNA can compromise reproductive success and survival in organisms. Genotoxicity in male germ cells is of particular concern because damage to DNA in sperm may not be repaired and the consequences of damaged genetic material may be transgenerational (from parent to offspring). An integrated approach across multiple levels of biological organization is necessary to establish linkages between exposure to genotoxicants and subsequent effects at molecular and higher levels of biological organization. This thesis addresses the relation between toxicant-induced genotoxicity and reproductive success in zebrafish, and focuses on a model genotoxicant (hydrogen peroxide) and dissolved metals (radionuclide or non-radioactive forms) under controlled laboratory conditions. Uptake and depuration kinetics of a mixture of radionuclides (54Mn, 60Co, 65Zn, 75Se, 109Cd, 110mAg, 134Cs, and 241Am) were investigated, and radiation dose estimations were computed to link exposure and bioaccumulation with radiation dose. Cobalt (Co, non-radioactive) was selected as an environmentally relevant toxicant for investigation of genotoxicity and effects on reproductive success with a focus on male fish. Chronic exposure (12-d) to 0 – 25 mg l-1 Co resulted in reduced numbers of spawned eggs, lower fertilization success, and reduced survival of larvae to hatching. In male fish, DNA damage was detected in sperm and genes involved in DNA repair (xrcc5, xrcc6, and rad51) were induced in testes from some Co treatments, generally consistent with reduced reproductive success. No change in expression of repair genes in larvae spawned from parents exposed to Co was observed. Overall, results indicate that DNA damage and induction of DNA repair genes can occur rapidly after exposure to genotoxicants and that, if exposure levels are elevated, negative effects on reproduction can occur. Results are considered with particular focus on implications of male genotoxicity on reproductive success and the potential for transgenerational effects of toxicants.International Atomic Energy Agenc

Effects of the sea lice bath treatment pharmaceuticals hydrogen peroxide, azamethiphos and deltamethrin on egg-carrying shrimp (Pandalus borealis)

This study investigated effects of sea lice pharmaceuticals on egg-bearing deep-water shrimp (Pandalus borealis). Both mortality and sub-lethal effects (behavior, embryo development, and reproductive output) were studied for each of three pharmaceuticals alone and in different sequential combinations. The most severe effect was observed for deltamethrin where 2 h exposure to 330 times diluted treatment dose (alone and in sequential application with hydrogen peroxide and azamethiphos) induced almost 100% mortality within a few days after exposure. Similar effects were not observed for hydrogen peroxide or azamethiphos. However, sequential treatment of hydrogen peroxide and azamethiphos (2 h exposure to each pharmaceutical; 500 times dilution) resulted in >40% mortality during the first week following treatment. No sub-lethal effects or loss of eggs in female shrimp could be related to exposure to the bath treatments. Future studies should investigate potential sub-lethal effects at exposure concentrations close to the no-effect concentration

Toxicity to sea urchin embryos of crude and bunker oils weathered under ice alone and mixed with dispersant

[EN] A multi-index approach (larval lenghthening and malformations, developmental disruption, and genotoxicity) was applied using sea-urchin embryos as test-organisms. PAH levels measured in the under-ice weathered aqueous fraction (UIWAF) were lower than in the low-energy water accommodated fraction (LEWAF) and similar amongst UIWAFs of different oils. UIWAFs and LEWAFs caused toxic effects, more markedly in UIWAFs, that could not be attributed to measured individual PAHs or to their mixture. Conversely, UIWAF was less genotoxic than LEWAF, most likely because naphthalene concentrations were also lower. In agreement, NAN LEWAF, the most genotoxic, exhibited the highest naphthalene levels. Dispersant addition produced less consistent changes in PAH levels and embryo toxicity in UIWAFs than in LEWAFs, and did not modify LEWAF genotoxicity. Overall, under ice weathering resulted in lowered waterborne PAHs and genotoxicity but augmented embryo toxicity, not modified by dispersant application.The authors would like to gratefully acknowledge financial support from the European Union's Horizon 2020 research and innovation program EU H2020-BG-2005-2 under grant agreement No 679266 (project GRACE), from the Spanish Ministry of Education, Culture and Sport through pre-doctoral fellowship FPU15/05517, and from the Basque Government through Consolidated Research Group GIC IT81013 & IT1302-19. The authors acknowledge Total Spain for kindly providing the dispersant

Behavioural and physiological impacts of low salinity on the sea urchin Echinus esculentus

Reduced seawater salinity as a result of freshwater input can exert a major influence on the ecophysiology of benthic marine invertebrates, such as echinoderms. While numerous experimental studies have explored the physiological and behavioural effects of short-term, acute exposure to low salinity in echinoids, surprisingly few have investigated the consequences of chronic exposure, or compared the two. In this study, the European sea urchin, Echinus esculentus was exposed to low salinity over the short-term (11, 16, 21, 26, and 31‰ for 24 hours) and longer-term (21, 26, and 31‰ for 25 days). Over the short-term, oxygen consumption, activity coefficient and coelomic fluid osmolality were directly correlated with reduced salinity, with 100% survival at ≥21‰ and 0% at ≤16‰. Over the longer-term at 21‰ (25 days), oxygen consumption was significantly higher, feeding was significantly reduced, and activity coefficient values were significantly lower than at control salinity (31‰). At 26‰, all metrics were comparable to the control by the end of the experiment, suggesting acclimation. Furthermore, beneficial functional resistance (righting ability and metabolic capacity) to acute low salinity was observed at 26‰. Osmolality values were slightly hyperosmotic to the external seawater at all acclimation salinities, while coelomocyte composition and concentration were unaffected by chronic low salinity. Overall, E. esculentus demonstrate phenotypic plasticity that enables acclimation to reduced salinity around 26‰; however, 21‰ represents a lower acclimation threshold, likely limiting its distribution in coastal areas prone to high freshwater input

Strategy Proposal for the Company Rajnošek, Ltd.

Import 22/07/2015Diplomová práce je zaměřena na zpracování návrhu strategie pro podnik Rajnošek s.r.o. Podnikatelská činnost tohoto podniku se týká autodopravy, zemních a jeřábnických prací v Jihomoravském kraji. V teoretické části jsou vymezeny základní pojmy, které nezbytně souvisí s tematickým celkem této práce. Také jsou zde popsány jednotlivé metody, které byly aplikovány na zkoumanou společnost při analýze celkového stavu firmy. V praktické části je nejprve detailně představen zvolený podnik a následně je provedeno několik typů analýzy, po jejichž vyhodnocení došlo k návrhu jednotlivých doporučení, jež by měla vést k žádoucím změnám a především k formulaci nejvhodnější firemní strategie.The thesis is focused on the development of the strategy proposal for the company Rajnošek s.r.o. The business activity of the company covers transport, earthworks and crane work in South-Moravian region. The theoretical part of the basic concepts that are necessarily associated with thematic units of this work . Also described are various methods that have been applied to the study of the organization in analyzing the overall condition of the company. In the practical part is the first detailed presentation of the selected company and subsequently made several types of analysis, evaluation, after which there was a draft of the recommendations which should lead to the desired changes and especially to the most appropriate formulation of corporate strategy.152 - Katedra podnikohospodářskávelmi dobř

The influence of temperature in sea urchin embryo toxicity of crude and bunker oils alone and mixed with dispersant

This investigation deals with how temperature influences oil toxicity, alone or combined with dispersant (D). Larval lengthening, abnormalities, developmental disruption, and genotoxicity were determined in sea urchin embryos for assessing toxicity of low-energy water accommodated fractions (LEWAF) of three oils (NNA crude oil, marine gas oil –MGO-, and IFO 180 fuel oil) produced at 5–25 °C. PAH levels were similar amongst LEWAFs but PAH profiles varied with oil and production temperature. The sum of PAHs was higher in oil-dispersant LEWAFs than in oil LEWAFs, most remarkably at low production temperatures in the cases of NNA and MGO. Genotoxicity, enhanced after dispersant application, varied depending on the LEWAF production temperature in a different way for each oil. Impaired lengthening, abnormalities and developmental disruption were recorded, the severity of the effects varying with oil, dispersant application and LEWAF production temperature. Toxicity, only partially attributed to individual PAHs, was higher at lower LEWAF production temperatures.The authors would like to gratefully acknowledge financial support from the European Union's Horizon 2020 research and innovation program EU H2020-BG-2005-2 under grant agreement No 679266 (project GRACE), from the Spanish Ministry of Education, Culture and Sport through pre-doctoral fellowship FPU15/05517, and from the Basque Government through Consolidated Research Group GIC IT1302-19 & IT1743-22. The authors acknowledge Total Spain for kindly providing the dispersant

Triploidy leads to a mismatch of smoltification biomarkers in the gill and differences in the optimal salinity for post-smolt growth in Atlantic salmon

Sterile triploid Atlantic salmon (Salmo salar) show inconsistent seawater grow-out, but the reason why remains unclear. The purpose of this study was to determine the salinity optima of triploid post-smolts. Diploids and triploids were assessed for smoltification status during an underyearling smolt regime before being transferred to one of four different salinities, 0, 11, 23 and 35 ppt at 12 °C and under 24 h continuous light for 83 days. During this period, fish growth, plasma biochemistry, and production traits (vertebral deformities, ocular cataracts, sexual maturation) were monitored. Molecular biomarkers in the gill (nkaα1a, nkaα1b, nkcc1a) suggested triploids reached peak smolt earlier than diploids and began the desmoltification process before the start of the salinity treatments, however this was not reflected in gill Na+/K+-ATPase enzyme activity. At the initiation of the salinity treatments triploids were significantly larger than diploids (mean weight g ± SE: 71 ± 0.7 and 87.2 ± 0.8 for diploids and triploids, respectively) and there was a ploidy effect on post-smolt growth, with body weight showing a clearer positive trend with salinity in diploids (0 < 11 = 23 = 35 ppt) than in triploids (0 < 11 < 35 = 23 ppt) (final mean weight g ± SE: 255.2 ± 7.4, 303.9 ± 9, 313.9 ± 9 and 342.4 ± 12 for diploids and 322.9 ± 9.7, 361.7 ± 10.7, 425.9 ± 12.1, 415.2 ± 12.2 for triploids at 0, 11, 23, and 35 ppt, respectively). Plasma Na+ and Cl− increased, but plasma pH decreased, with increasing salinity in both ploidy. However, ploidy only had transient effects on plasma biochemistry depending on the salinity treatment. There was no ploidy effect on vertebral deformities (21% of both ploidy had one or more deformed vertebra). In contrast, triploids had a significantly higher prevalence of ocular cataracts (84 vs 98% in diploids and triploids, respectively) with a higher mean cataract score (mean ± SE: 1.93 ± 0.1 and 2.78 ± 0.1 for diploids and triploids, respectively), but a significantly lower prevalence of pubertal male post-smolts (15 vs 2% in diploids and triploids, respectively). Salinity treatment had no effect on vertebral deformities, cataracts, or post-smolt sexual maturation. In summary, there was a ploidy mismatch for smoltification biomarkers in the gill and salinity had a strong effect on post-smolt growth, but the effects were ploidy dependent.publishedVersio

Combined effects of crude oil exposure and warming on eggs and larvae of an arctic forage fish

Climate change, along with environmental pollution, can act synergistically on an organism to amplify adverse effects of exposure. The Arctic is undergoing profound climatic change and an increase in human activity, resulting in a heightened risk of accidental oil spills. Embryos and larvae of polar cod (Boreogadus saida), a key Arctic forage fish species, were exposed to low levels of crude oil concurrently with a 2.3 °C increase in water temperature. Here we show synergistic adverse effects of increased temperature and crude oil exposure on early life stages documented by an increased prevalence of malformations and mortality in exposed larvae. The combined effects of these stressors were most prevalent in the first feeding larval stages despite embryonic exposure, highlighting potential long-term consequences of exposure for survival, growth, and reproduction. Our findings suggest that a warmer Arctic with greater human activity will adversely impact early life stages of this circumpolar forage fish

A gap analysis on modelling of sea lice infection pressure from salmonid farms. I. A structured knowledge review

Sustainability of aquaculture, an important component of the blue economy, relies in part on ensuring assessment of environmental impact and interactions relating to sea lice dispersing from open pen salmon and trout farms. We review research underpinning the key stages in the sea lice infection process to support modelling of lice on wild salmon in relation to those on farms. The review is split into 5 stages: larval production; larval transport and survival; exposure and infestation of new hosts; development and survival of the attached stages; and impact on host populations. This modular structure allows the existing published data to be reviewed and assessed to identify data gaps in modelling sea lice impacts in a systematic way. Model parameterisation and parameter variation is discussed for each stage, providing an overview of knowledge strength and gaps. We conclude that a combination of literature review, empirical data collection and modelling studies are required on an iterative basis to ensure best practice is applied for sustainable aquaculture. The knowledge gained can then be optimised and applied at regional scales, with the most suitable modelling frameworks applied for the system, given regional limitations

A gap analysis on modelling of sea lice infection pressure from salmonid farms. II. Identifying and ranking knowledge gaps: output of an international workshop

Sea lice are a major health hazard for farmed Atlantic salmon in Europe, and their impact is felt globally. Given the breadth of ongoing research in sea lice dispersal and population modelling, and focus on research-led adaptive management, we brought experts together to discuss research knowledge gaps. Gaps for salmon lice infection pressure from fish farms were identified and scored by experts in sea lice-aquaculture-environment interactions, at an international workshop in 2021. The contributors included experts based in Scotland, Norway, Ireland, Iceland, Canada, the Faroe Islands, England and Australia, employed by governments, industry, universities and non-government organisations. The workshop focused on knowledge gaps underpinning 5 key stages in salmon lice infection pressure from fish farms: larval production; larval transport and survival; exposure and infestation of new hosts; development and survival of the attached stages; and impact on host populations. A total of 47 research gaps were identified; 5 broad themes emerged with 13 priority research gaps highlighted as important across multiple sectors. The highest-ranking gap called for higher quality and frequency of on-farm lice count data, along with better sharing of information across sectors. We highlight the need for synergistic international collaboration to maximise transferable knowledge. Round table discussions through collaborative workshops provide an important forum for experts to discuss and agree research priorities