Oksüdatiivse stressi mõõtmismeetodite valideerimine ja rakendamine vabalt elavate lindude redoksfüsioloogia kirjeldamisel

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Hapnik on mürgine gaas, kuna võib kergesti moodustada erinevaid bioloogilisi struktuure kahjustavaid reaktiivseid radikaale. Selleks, et vältida hapniku toksilist mõju, on organismidel evolutsiooni käigus tekkinud suur hulk erinevaid antioksüdantseid kaitsemehhanisme. Oksüdatiivne stress ehk kehas kahjustusi põhjustav tasakaalu puudumine reaktiivsete hapnikuosakeste ja antioksüdantide hulga vahel, on arvatavasti olnud oluline organismide evolutsiooni kujundav jõud. Samas on oksüdatiivset stress raske mõõta, mistõttu on selle roll metsikute loomade igapäevaelu mõjutajana endiselt küsitav. Selle väitekirja eesmärgiks on täpsustada mõningate, ökoloogilistes uurimustes laia kasutust leidvate, oksüdatiivse stressi biomarkerite kasutatavust oksüdatiivse stressi mõõtmiseks. Kokkuvõtvalt selgub, et mitmed laia kasutust leidvad verest mõõdetavad oksüdatiivse stressi biomarkerid ei ole sobilikud oksüdatiivse stressi mõõtmiseks. Eriti kaheldav on d-ROMs testi sobilikus oksüdatiivse staatuse hindamiseks. Samas muutused erütrotsüütide glutatiooni kontsentratsioonis peegeldavad suurema tõenäosusega muutuseid oksüdatiivses seisundis. Peamiselt rõhutab see töö aga, et oksüdatiivset stressi ei saa mõõta kasutades vaid mõnda kude, ajahetke või biomarkerit. Seetõttu pole enne mõõtmistehnikate täiustumist võimalik usaldusväärselt hinnata oksüdatiivse stressi rolli isendite elukäikude mõjutajana.Oxygen is a noxious molecule that easily forms radicals that readily react with biological compounds. In order to protect themselves from oxygen induced damage organisms have developed different types of antioxidant defences. For a long time oxidative stress, a body-damaging imbalance between reactive oxygen species and antioxidants, has been proposed to be an important force shaping how aerobic organisms are built and maintained. Nevertheless, it is hard to quantify oxidative stress. Thus, the importance of oxidative stress in everyday life of wild animals is still under debate. This thesis aims to clarify the suitability of some widely used biomarkers of antioxidant protection and oxidative damage for use in studies oxidative stress ecology. Ultimately, general insensitivity of some popular blood based biomarkers of oxidative stress is highlighted. In particular d-ROMs test appears to be unsuitable to measure oxidative status, while erythrocyte gluthathione concentration appears to be more suitable to measure occurrences oxidative stimulus. However, most importantly this thesis highlights that oxidative stress cannot be measured using only few tissues, timepoints or biomarkers. Thus, advances in measurement techniques are required to reliably demonstrate involvement of oxidative stress in mediating life history trade-offs

Mothers of small-bodied children and fathers of vigorous sons live longer

Life-history traits (traits directly related to survival and reproduction) co-evolve and materialize through physiology and behavior. Accordingly, lifespan can be hypothesized as a potentially informative marker of life-history speed that subsumes the impact of diverse morphometric and behavioral traits. We examined associations between parental longevity and various anthropometric traits in a sample of 4,000–11,000 Estonian children in the middle of the 20th century. The offspring phenotype was used as a proxy measure of parental genotype, so that covariation between offspring traits and parental longevity (defined as belonging to the 90th percentile of lifespan) could be used to characterize the aggregation between longevity and anthropometric traits. We predicted that larger linear dimensions of offspring associate with increased parental longevity and that testosterone-dependent traits associate with reduced paternal longevity. Twelve of 16 offspring traits were associated with mothers' longevity, while three traits (rate of sexual maturation of daughters and grip strength and lung capacity of sons) robustly predicted fathers' longevity. Contrary to predictions, mothers of children with small bodily dimensions lived longer, and paternal longevity was not linearly associated with their children's body size (or testosterone-related traits). Our study thus failed to find evidence that high somatic investment into brain and body growth clusters with a long lifespan across generations, and/or that such associations can be detected on the basis of inter-generational phenotypic correlations

Effects of environmentally relevant concentrations of microplastics on amphipods

Lack of microplastics (MP) toxicity studies involving environmentally relevant concentrations and exposure times is concerning. Here we analyzed the potential adverse effects of low density polyethylene (LDPE) MP at environmentally relevant concentration in sub-chronic exposure to two amphipods Gmelinoides fasciatus and Gammarus lacustris, species that naturally compete with each other for their habitats. 14-day exposure to 2 μg/L (8 particles/L corresponding to low exposure) and 2 mg/L (~8400 particles/L, corresponding to high exposure) of 53–100 μm LDPE MP were used to assess ingestion and egestion of MP, evaluate its effects on amphipod mortality, swimming ability and oxidative stress level. Both amphipod species were effectively ingesting and egesting LDPE MP. On the average, 0.8 and 2.5 MP particles were identified in the intestines of each amphipod exposed to 2 μg/L and 2 mg/L LDPE MP, respectively. Therefore, intestinal MP after 14-day exposure did not fully reflect the differences in LDPE MP exposure concentrations. Increased mortality of both amphipods was observed at 2 mg/L LDPE MP and in case of G. lacustris also at 2 μg/L exposure. The effect of LDPE on swimming activity was observed only in case of G. fasciatus. Oxidative stress marker enzymes SOD, GPx and reduced glutathione GSH varied according to amphipod species and LDPE MP concentration. In general G. lacustris was more sensitive towards LDPE MP induced oxidative stress. Overall, the results suggested that in MP polluted environments, G. lacustris may lose its already naturally low competitiveness and become overcompeted by other more resistant species. The fact that in the sub-chronic foodborne exposure to environmentally relevant and higher LDPE MP concentrations all the observed toxicological endpoints were affected refers to the potential of MP to affect and disrupt aquatic communities in the longer perspective.This research was funded by the Estonian Research Council (Estonia) grants PUT1512 (M. Heinlaan and M. Raudna-Kristoffersen) and PRG1427 (M. Heinlaan). This work was also supported by the research grants PSG653 (R. Kreitsberg and R. Meitern) and PRG1496 (A. Ivask) of the Estonian Research Council. The project was carried out in collaboration with Vortsj ˜ arv ¨ Centre for Limnology of the Estonian University of Life Sciences (EMU). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 951963

Differences on the level of hepatic transcriptome between two flatfish species in response to liver cancer and environmental pollution levels

Environmental factors can cause cancer in both wild animals and humans. In ecological settings, genetic variation and natural selection can sometimes produce resilience to the negative impacts of environmental change. An increase in oncogenic substances in natural habitats has therefore, unintentionally, created opportunities for using polluted habitats to study cancer defence mechanisms. The Baltic and North Sea are among the most contaminated marine areas, with a long history of pollution. Two flatfish species (flounder, Platichthys flesus and dab, Limanda limanda) are used as ecotoxicological indicator species due to pollution-induced liver cancer. Cancer is more prevalent in dab, suggesting species-specific differences in vulnerability and/or defence mechanisms. We conducted gene expression analyses for 30 flatfishes. We characterize between- and within-species patterns in potential cancer-related mechanisms. By comparing cancerous and healthy fishes, and noncancerous fishes from clean and polluted sites, we suggest also genes and related physiological mechanisms that could contribute to a higher resistance to pollution-induced cancer in flounders. We discovered changes in transcriptome related to elevated pollutant metabolism, alongside greater tumour suppression mechanisms in the liver tissue of flounders compared to dabs. This suggests either hormetic upregulation of tumour suppression or a stronger natural selection pressure for higher cancer resistance for flounders in polluted environment. Based on gene expression patterns seen in cancerous and healthy fish, for liver cancer to develop in flounders, genetic defence mechanisms need to be suppressed, while in dabs, analogous process is weak or absent. We conclude that wild species could offer novel insights and ideas for understanding the nature and evolution of natural cancer defence mechanisms.We are grateful to the crew of RW Walther Herwig III for all-round help during the fieldwork. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 951963.We are grateful to the crew of RW Walther Herwig III for all-round help during the fieldwork. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 951963

Second Workshop on Estimation with the RDBES data model (WKRDB-EST2; outputs from 2020 meeting)

This report shows how the new RDBES that is currently in development will be better able to support the recast EU Data Collection Framework (Regulation (EU) 2017/1004) than the existing RDB. The RDBES is an essential platform for MS and RCGs to fulfil their obligations towards documenting and improving data quality and designing and implementing regional sampling designs. The evaluation of data precision was performed using two complementary techniques. For relatively simple sampling designs it is possible to use analytical functions to calculate the precision (or a related statistical measure such as variance) of a statistical estimate. These calculations and implementations of them in R code are presented in this report. For more complicated sampling designs, the use of analytical functions is usually not feasible. In these cases, it is necessary to evaluate precision using numerical techniques, the main one of which is bootstrapping. This report discussed when bootstrapping is appropriate and gives several worked examples describing how bootstrapping can be applied in different cases. The evaluation of bias is a difficult subject and is hard to quantify. The approach followed in this report was to build on the previous work available in the ICES literature and identify and enumerate the main common sources of bias in catch sampling programs they describe. The information was collated and an evaluation performed as to whether data stored using the RDBES data format and reports issues from them can inform about the potential for bias in catch estimates. A set of example reports was coded that demonstrates the utility of the RDBES in relation to bias issues and can already help member states to identify how deviations in their sampling programmes and sampling variability may potentially lead to bias in their catch estimates

The Third Workshop on Population of the RDBES Data Model (WKRDB-POP3)

The aims of this workshop were to explain the data model developed for the commercial fisheries Regional Database and Estimation System (RDBES), assist in populating it with real data for the second test data call for the RDBES, and encourage participants to take part in ongoing testing of the RDBES data submission system. This report documents the progress that participants have done to prepare their institutes for future use of the RDBES system. Some issues with data conversion have been identified and are documented in this report. None of the identified issues are thought to be serious impediments to moving forward with the RDBES development according to the roadmap decided by the Steering Committee of the Regional Fisheries Database in 2020. The RDBES Core Group (the group of people developing the RDBES data model) and ICES Data Centre will look at the results of this workshop and either respond to individual questions or adapt the data model and documentation as required. The workshop concluded and reported before the deadline of the test data call. For a complete test of the data model, all participants were encouraged to complete the data call. A report on the degree of completion of the data call may be expected from WGRDBESGOV which convenes after the data call deadline

On the methodological limitations of detecting oxidative stress: effects of paraquat on measures of oxidative status in greenfinches

Oxidative stress (OS) is widely believed to be responsible for the generation of trade-offs in evolutionary ecology by means of constraining investment into a number of components of fitness. Yet, progress in understanding the true role of OS in ecology and evolution has remained elusive. Interpretation of current findings is particularly hampered by the scarcity of experiments demonstrating which of the many available parameters of oxidative status respond most sensitively to and are relevant for measuring OS. We addressed these questions in wild-caught captive greenfinches (Carduelis chloris) by experimental induction of OS by administration of the pro-oxidant compound paraquat with drinking water. Treatment induced 50% mortality, a significant drop in body mass and an increase in oxidative DNA damage and glutathione levels in erythrocytes among the survivors of the high paraquat (0.2 g l(-1) over 7 days) group. Samples taken 3 days after the end of paraquat treatment showed no effect on the peroxidation of lipids (plasma malondialdehyde), carbonylation of proteins (in erythrocytes), parameters of plasma antioxidant protection (total antioxidant capacity and oxygen radical absorbance), uric acid or carotenoids. Our findings of an increase in one marker of damage and one marker of protection from the multitude of measured variables indicate that detection of OS is difficult even under the most stringent experimental induction of oxidative insult. We hope that this study highlights the need for reconsideration of over-simplistic models of OS and draws attention to the limitations of detection of OS due to time-lagged and hormetic upregulation of protective mechanisms. This study also underpins the diagnostic value of measurement of oxidative damage to DNA bases and assessment of erythrocyte glutathione levels