Oksüdatiivsed kaitsereaktsioonid immuunökoloogilises kontekstis: lämmastikoksiidi produktsiooni ning oksüdatiivse purske mõõtmise meetodite kohandamine ja rakendamine värvulisele

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Immuunökoloogia aluseks on põhimõte, et immunvastused on kulukad ning seetõttu omavad lõivsuhteid teiste elukäigu tunnustega. Samas pole veel selge, mis võiks olla immunvastuse kulukuse põhjuseks. Üheks võimalikuks variandiks on immuunvastuse käigus tekitatud patogeenide hävitamiseks mõeldud reaktiivsete osakeste poolt tekitatud koekahjustused. Selle teooria kontrollimisel on takistavaks saanud nii immuunökoloogias kasutusel olevate meetodite vähesus kui ka asjaolu, et immuunsüsteem on väga keeruline ning põhjalikult seotud nii endokriinse kui ka närvisüsteemiga. Antud töös on immunökoloogia sagedastele uurimisobjektidele, värvulistele lindudele, kasutamiseks kohandatud kaks meetodit, mis mõõdavad kaasasündinud immuunvastuse käigus tekitatud reaktiivseid osakesi- lämmastikoksiidi ning oksüdatiivse purske käigus tekkivaid reaktiivseid osakesi. Seejärel on neid uusi meetodeid rakendatud uurimaks immuunsüsteemi seoseid endokriinse ja närvisüsteemiga ning selleks, et testida antioksüdandi karotenoidi mõju immuunvastusele.Immunoecology is based on the principle that immune defences are costly and therefore have trade-offs with other life-history traits. At the moment, however, the reasons why immune defences are costly, are poorly understood. One of the possible versions is the collateral damage of tissues by reactive oxygen species that are produced during immune response to destroy pathogens. The controlling of this theory has turned out to be difficult for two main reasons- lack of methods used in immunoecology and the fact that immune system is very complex and has tight interconnections with nervous and endocrine systems. In the current thesis I have modified two methods for use with immunoecological model species, passerine birds. These methods measure reactive species produced during innate immune responses - nitric oxide and reactive species produced during oxidative burst. Subsequently I used these new methods to study connections between immune system and endocrine and nervous systems and to test the effects of antioxidant carotenoid to immune response

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

Oxidative stress and life histories: unresolved issues and current needs.

Life-history theory concerns the trade-offs that mold the patterns of investment by animals between reproduction, growth, and survival. It is widely recognized that physiology plays a role in the mediation of life-history trade-offs, but the details remain obscure. As life-history theory concerns aspects of investment in the soma that influence survival, understanding the physiological basis of life histories is related, but not identical, to understanding the process of aging. One idea from the field of aging that has gained considerable traction in the area of life histories is that life-history trade-offs may be mediated by free radical production and oxidative stress. We outline here developments in this field and summarize a number of important unresolved issues that may guide future research efforts. The issues are as follows. First, different tissues and macromolecular targets of oxidative stress respond differently during reproduction. The functional significance of these changes, however, remains uncertain. Consequently there is a need for studies that link oxidative stress measurements to functional outcomes, such as survival. Second, measurements of oxidative stress are often highly invasive or terminal. Terminal studies of oxidative stress in wild animals, where detailed life-history information is available, cannot generally be performed without compromising the aims of the studies that generated the life-history data. There is a need therefore for novel non-invasive measurements of multi-tissue oxidative stress. Third, laboratory studies provide unrivaled opportunities for experimental manipulation but may fail to expose the physiology underpinning life-history effects, because of the benign laboratory environment. Fourth, the idea that oxidative stress might underlie life-history trade-offs does not make specific enough predictions that are amenable to testing. Moreover, there is a paucity of good alternative theoretical models on which contrasting predictions might be based. Fifth, there is an enormous diversity of life-history variation to test the idea that oxidative stress may be a key mediator. So far we have only scratched the surface. Broadening the scope may reveal new strategies linked to the processes of oxidative damage and repair. Finally, understanding the trade-offs in life histories and understanding the process of aging are related but not identical questions. Scientists inhabiting these two spheres of activity seldom collide, yet they have much to learn from each other

Coccidian Infection Causes Oxidative Damage in Greenfinches

The main tenet of immunoecology is that individual variation in immune responsiveness is caused by the costs of immune responses to the hosts. Oxidative damage resulting from the excessive production of reactive oxygen species during immune response is hypothesized to form one of such costs. We tested this hypothesis in experimental coccidian infection model in greenfinches Carduelis chloris. Administration of isosporan coccidians to experimental birds did not affect indices of antioxidant protection (TAC and OXY), plasma triglyceride and carotenoid levels or body mass, indicating that pathological consequences of infection were generally mild. Infected birds had on average 8% higher levels of plasma malondialdehyde (MDA, a toxic end-product of lipid peroxidation) than un-infected birds. The birds that had highest MDA levels subsequent to experimental infection experienced the highest decrease in infection intensity. This observation is consistent with the idea that oxidative stress is a causative agent in the control of coccidiosis and supports the concept of oxidative costs of immune responses and parasite resistance. The finding that oxidative damage accompanies even the mild infection with a common parasite highlights the relevance of oxidative stress biology for the immunoecological research

Use of Duroc mixed sperm for production of fattening pigs

Magistritöö Loomakasvatuse õppekavalMagistritöö eesmärk oli uurida Eestis djuroki tõugu kultide segusperma kasutamise mõjusid emiste viljakusnäitajatele. Töö kirjanduse analüüsis antakse ülevaade seakasvatusest Eestis, kunstliku seemendamise eelistest, sperma kvaliteedi mõõtmisest, sperma kvaliteedi mõjust pesakonna suurusele, tõulisuse mõjust emise viljakuse näitajatele ning kultide segusperma kasutamisest seemendamisel. Töö tulemuste osa põhineb Eesti Tõusigade Aretusühistu (ETSAÜ) seemendusjaamast pärit sperma kvaliteedi andmetel ning Eesti Jõudluskontrollikeskuse emiste jõudlusandmetel 2020. aasta kohta. Magistritöös ei õnnestunud segavate tegurite tõttu näidata djuroki seguspermaga seemendamise positiivset mõju emise viljakusnäitajatele, kuid samas pole välistatud selle mõju olemasolu. Võõrutatud põrsaste arvu pesakonnas mõjutasid uuritud sperma näitajatest spermide koguhulk proovis, progressiivne seguskoor ja spermide järkjärguline liikuvus. Pesakonna tõulisusel oli statistiliselt oluline mõju kõigile uuritud emise viljakustunnustele. Elusalt sündinud põrsaste arvule pesakonnas, surnult sündinud põrsaste arvule pesakonnas ja surnud imikpõrsaste arvule pesakonnas avaldasid statistiliselt olulist mõju farm, kus emist peeti, emise seemendamise kuu ja emist seemendanud tehniku isik. Emiste viljakust mõjutavad samal ajal väga paljud erinevad tegurid, nii geneetilised kui ka keskkonnaga seotud. Oluliselt aitab viljakusnäitajate paranemisele kaasa ristamisel tekkiv heteroosiefekt, mistõttu on ristamistel seakasvatuses väga oluline roll.The aim of the Master’s thesis was to investigate the effect of using mixed sperm of duroc boars to the fertility of sows in Estonia. In literature review following topics are covered: pig industry in Estonia, advantages of artificial insemination, measurements of sperm quality, effects of sperm quality on litter size, effect of breed on fertility and using pooled semen in artificial insemination. Results are based on Estonian Pig Breeding Association´s artificial insemination station data about sperm quality combined with data from Estonian Livestock Performance Recording Ltd on sows fertility in 2020. Due to confounding factors it was not possible to show effect of duroc pooled semen on fertility of the sow, but the effect can not be excluded. Number of weaned piglets in litter was affected by total amount of sperm in dose, progressive composite score and progressive motility of sperm. Litter breed affected significantly all the fertility aspects studied in sows. Piglets born alive in litter, piglets bord dead in litter and piglet losses in litter were significantly affected by farm, insemination month and insemination technician. Fertility of sows is simultaneously affected by variety of factors, both environmental and genetic. Heterosis effect that arises from crossbreeding increases fertility and therefore crossbreeding has essential role in pig industry

Data from: Causal link between insulin-like growth factor 1 and growth in nestlings of a wild passerine bird

Life history of animals is strongly linked with the variability in postnatal growth rates, because the ability to achieve necessary body mass early in life is directly connected with the ability to survive and reproduce later in life. Surprisingly, little is known about the physiological mechanisms connecting food availability with the variability of growth in wild animals. We used a hormonal injection treatment in free-living nestlings of the pied flycatcher (Ficedula hypoleuca). In doing this, we aimed to see how their plasma insulin-like growth factor 1 (IGF-1) levels and its mediation of growth rate vary in response to administration of exogenous IGF-1 during the early period of postnatal development. We showed that the levels of IGF-1 as well as growth rate and body size, in terms of body mass and tarsus length, were significantly higher in IGF-1-injected nestlings, compared with those in the control group. These differences became especially pronounced from day 7 post-hatch onwards during the 13-day nestling period. Additionally, the proportional investment into growth was more profoundly downregulated in IGF-1-injected nestlings at the end of the nestling period, which achieved fledging size earlier, compared with control nestlings. Our results are the first to highlight IGF-1 as the causal link between growth conditions and variability of growth rate and body size in wild vertebrates. Interestingly, the change in IGF-1 levels also showed a plausible, distinct adaptive age- and physical maturity-dependent pattern in nestlings to match the benefits gained by them when investing in growth, with the cost endured during the early days of postnatal development to maximize their fitness. Therefore, this mechanism might be among those mediating the maintenance of genetic variability in growth rates in populations, presumably regardless of the presence of strong directional selection acting upon them

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

data-Lodjak.et.al-2016-FuncEcol-IGF1

IGF-1 and growth rate data for pied flycatcher nestlings. IGF-1 injection study