<p>The aim of this study was to investigate the effects of water temperature and salinity on lipid nutrition of farmed Atlantic salmon (<i>Salmo salar L</i>.) parr and smolt. Salmon parr were held at low water temperature (2°C) for six months while being fed feeds that differed in oil source (i.e. marine fish oil or vegetable oil blend) and concentration (low, 21% and high, 34%). The responses at low temperature were compared with those of fish held at 8°C using full-factorial design.</p><p>Feeding and growth were maintained at 2°C, although at lower rates than at 8°C. Growth and feed utilisation improved over time, suggestive for a long-term acclimation response in fish held at low temperature. Overall feed efficiency was better at the lower temperature. A gradual decrease in growth rate and feed utilisation was seen at the higher temperature as the fish grew larger.</p><p>The fish compensated for reduced energy density by increasing feed intake. At the higher temperature, better growth was found for fish fed the low-fat feeds, and there was also a tendency for improved growth when vegetable oil was used. Thus, there were no signs that vegetable oils are inferior to marine fish oil in promoting growth of Atlantic salmon parr in fresh water.</p><p>Fish fed high fat feed were fatter than fish fed low fat feed, suggestive of lipostatic regulation of feed intake. Fat and protein digestibility were high at both 2°C and 8°C, although both fat and protein digestibility were lower at 2°C. At the lower temperature, increased dietary fat level increased the fat digestibility, and improved protein digestibility were seen when vegetable oil was included in the feed. Protein retention was higher at the higher temperature irrespective of feed treatment, indicating that proteins were both readily digested and converted into new tissues.</p><p>The effects of feed treatment on low temperature acclimation responses were assessed from deposition of dietary fatty acids in fish tissues and from n-3 and n-6 essential fatty acid (EFA) budgets. Fatty acid composition of polar (membrane) and non-polar (storage) lipids in muscle, viscera and carcass were markedly influenced by the dietary oil, and non-polar lipids were more influenced than polar lipids. The retention n-6 EFAs was lower than for n- 3 EFAs, and was independent of temperature. The retention of n-3 EFAs retention was higher at the 2°C, especially amongst fish given the fish oil based diets. This may be a reflection of the importance of n-3 HUFAs during low temperature acclimation. However, the unsaturation (UFA:SFA ratio) of polar lipids was higher in fish fed the vegetable oils than for fish fed fish oil based feed. This may imply that vegetable oils produced fish that were better able to withstand exposure to low temperature, while having membrane lipids less susceptible to oxidative damage, due to the lower contents of n-3 HUFAs (mainly EPA and DHA).</p><p>The six months feeding period in freshwater was followed by parr-smolt transformation, and a subsequent 42-days on-growing in seawater. Feed history during freshwater rearing influenced on-growth of smolts. A positive effect of using a vegetable oil was indicated, but this effect was only seen when there was a shift to a high-lipid fish oil based feed at the time of transfer to seawater.</p><p>As such, it was evident that use of vegetable oils in freshwater feed did not interfere with low temperature acclimation or parr-smolt transformation of juvenile salmon, and subsequent on-growing in seawater was better when vegetable oil had been used in the feed. This indicates that fatty acid (lipid) requirement of Atlantic salmon are probably different in fresh water and seawater, and that these changes are linked to parr-smolt transformation. It could be speculated that that salinity may be more important than temperature as an environmental influence on the fatty acid requirements of Atlantic salmon.</p> / <p>Målet med dette studiet har vært å undersøke vanntemperaturens og saltholdighetens innvirkning på lipidernæringen hos parr og smolt av oppdrettet atlantisk laks (<i>Salmo salar L.</i>). Lakseparr ble holdt ved lav vanntemperatur (2ºC) i seks måneder mens de ble fôret med en av fire fôrtyper med ulike fettkilde (dvs. marin fiskeolje eller vegetabilsk olje) og ulik konsentrasjon (lav, 21% og høy, 34%). Responsene ved den lave temperaturen ble sammenlignet med responsene en fikk hos fisk holdt ved 8ºC i et full-faktorielt forsøksdesign.</p><p>Fôrinntak og vekst ble opprettholdt ved 2ºC, men var lavere enn ved 8ºC. Over tid ble vekst og fôrutnyttelse forbedret, noe som indikerer en langtids akklimeringsrespons hos fisken ved den lave temperaturen. Totalt sett var utnyttelsen av fôret bedre ved den laveste temperaturen. En kunne observere en gradvis reduksjon i veksthastighet og fôrutnyttelse ved den høyeste temperaturen ettersom fisken ble større.</p><p>Fisken kompenserte for lavere energitetthet i fôret ved å øke fôrinntaket. Ved den høyeste temperaturen var veksten bedre hos fisk fôret med lav-fett-fôrene. Det var også en tendens til forbedret tilvekst når vegetabilsk olje ble brukt. Det var ingen tegn til at vegetabilsk olje var dårligere enn marin fiskeolje til å fremme vekst hos lakseparr i ferskvann.</p><p>Fisken som ble fôret med høy-fett-fôr ble fetere enn den som fikk lav-fett-fôr. Det indikerer lipostatisk regulering av fôrinntak. Fett- og proteinfordøyeligheten var høy både ved 2ºC og 8ºC, selv om både fett- og proteinfordøyeligheten var lavest ved 2ºC. Ved den laveste temperaturen, ga økt fettinnhold en forbedret fettfordøyelighet, og bruk av vegetabilsk olje i fôret ga bedre proteinfordøyelighet. Proteinretensjonen var høyere ved den høyeste temperaturen uavhengig av fôrtype, noe som indikerer at proteinet ble både lett fordøyd og omdannet til nytt vev.</p><p>Effektene av fôrtype på akklimeringen til lav temperatur ble bestemt fra deponeringen av fettsyrer fra fôret i ulike vev og fra budsjetter for n-3 og n-6 essensielle fettsyrer (EFS). Fettsyresammensetningen i polare (membran) lipider og upolare (lagrings) lipider i muskel, innvoller og ’rest’ ble tydelig påvirket av oljene i fôret, og de upolare lipidene ble mer påvirket enn de polare lipidene. Retensjonen av n-6 EFS var lavere enn for n-3 EFS, og var uavhengig av temperatur. Retensjonen av n-3 EFS var høyere ved 2ºC, spesielt hos fisk som fikk et fiskeoljebasert fôr. Dette kan reflektere betydningen av n-3 HUFA fettsyrer i akklimeringen til lav temperatur. Imidlertid var de polare lipider hos fisk som ble gitt fôr med vegetabils olje, mer umettet (UFA:SFA forhold) enn hos fisk gitt fôr med marine fiskeoljer. Dette kan bety at vegetabilske oljer produserte fisk som var bedre i stand til å tåle eksponering til lav temperatur, samtidig som membranlipidene var mindre utsatt for oksidering som følge av et lavere innhold av n-3 HUFA fettsyrer (hovedsaklig EPA og DHA).</p><p>Etter seks måneder i ferskvann ble fisken smoltifisert, etterfulgt av en 42-dagers periode i sjøvann. Fôrhistorie i ferskvannsfasen påvirket påvekst hos smolt. En positiv effekt av vegetabilsk olje ble funnet, men denne effekten ble bare funnet i grupper som hadde et skifte til et høy-fett-fiskeoljefôr ved overføring til sjøvann. Det var derfor tydelig at vegetabilsk olje ikke hadde negative konsekvenser for akklimering til lav temperatur eller for smoltifiseringen hos unglaks, og påfølgende tilvekst i sjøvann var bedre når vegetabilske oljer hadde blitt brukt. Dette indikerer at fettsyre (fett) behovet til atlantisk laks er forskjellig mellom ferskvann og sjøvann, og at forskjellene er knyttet til smoltifiseringen. Det kan derfor spekuleres i om saltholdigheten i miljøet er viktigere enn temperaturen i å bestemme fettsyrebehovet hos atlantisk laks.</p> / Papers II and V reprinted with kind permission of Elsevier, sciencedirect.com.

<p>Hvordan lærer og husker vi dufter? Hvordan skiller vi dem fra hverandre? </p><p>Det finnes liten kunnskap om hvilke duftsubstanser ulike lukteceller er utviklet for. I dag er gener for luktereseptorer identifisert i mange organismer, men kunnskapen om relevante duftstimuli mangler. Denne kunnskapen kan kun komme fra fysiologiske studier. I laboratoriet ble det brukt beslektede skadeinsekter som modeller for å studere innkoding av luktinformasjon i sanseceller og generelle prinsipper for luktesansens mekanismer.</p><p>Dette ble utført ved bruk av elektrofysiologiske målinger av nerveimpulser fra enkelte celler på insektantennene, med direkte kopling til kjemiske analyser av substansene avgitt av plantene. Resultatene har gitt ny kunnskap om hvilke plantesubstanser disse insektene detekterer i naturen. I tillegg har resultatene vist at luktecellene kan klassifiseres i distinkte typer, og samme type finnes hos de tre beslektede artene. Hver type er spesialisert for en enkelt substans, men de svarer også på høye konsentrasjoner av noen få andre substanser med lignende molekylstrukturer. Det er ingen overlapping av substanser mellom de ulike celletypene, noe som viser hvordan luktinformasjonen formidles via spesifikke nerveceller til hjernen hos disse insektene. Atferdsreaksjoner på en spesielt interessant substans viste at substansen økte tiltrekningen av gravide hunninsekter og økte antallet egg lagt på planter med substansen.</p><p>Å kjenne de biologiske luktesubstansene er viktig for å studere luktesansen generelt. Informasjon om hvilke plantedufter de studerte insektene lukter, kan brukes for å bekjempe skadene de påfører avlinger over hele verden.</p>

Hvordan lærer og husker vi dufter? Hvordan skiller vi dem fra hverandre? Det finnes liten kunnskap om hvilke duftsubstanser ulike lukteceller er utviklet for. I dag er gener for luktereseptorer identifisert i mange organismer, men kunnskapen om relevante duftstimuli mangler. Denne kunnskapen kan kun komme fra fysiologiske studier. I laboratoriet ble det brukt beslektede skadeinsekter som modeller for å studere innkoding av luktinformasjon i sanseceller og generelle prinsipper for luktesansens mekanismer. Dette ble utført ved bruk av elektrofysiologiske målinger av nerveimpulser fra enkelte celler på insektantennene, med direkte kopling til kjemiske analyser av substansene avgitt av plantene. Resultatene har gitt ny kunnskap om hvilke plantesubstanser disse insektene detekterer i naturen. I tillegg har resultatene vist at luktecellene kan klassifiseres i distinkte typer, og samme type finnes hos de tre beslektede artene. Hver type er spesialisert for en enkelt substans, men de svarer også på høye konsentrasjoner av noen få andre substanser med lignende molekylstrukturer. Det er ingen overlapping av substanser mellom de ulike celletypene, noe som viser hvordan luktinformasjonen formidles via spesifikke nerveceller til hjernen hos disse insektene. Atferdsreaksjoner på en spesielt interessant substans viste at substansen økte tiltrekningen av gravide hunninsekter og økte antallet egg lagt på planter med substansen. Å kjenne de biologiske luktesubstansene er viktig for å studere luktesansen generelt. Informasjon om hvilke plantedufter de studerte insektene lukter, kan brukes for å bekjempe skadene de påfører avlinger over hele verden.

The aim of this study was to investigate the effects of water temperature and salinity on lipid nutrition of farmed Atlantic salmon (Salmo salar L.) parr and smolt. Salmon parr were held at low water temperature (2°C) for six months while being fed feeds that differed in oil source (i.e. marine fish oil or vegetable oil blend) and concentration (low, 21% and high, 34%). The responses at low temperature were compared with those of fish held at 8°C using full-factorial design. Feeding and growth were maintained at 2°C, although at lower rates than at 8°C. Growth and feed utilisation improved over time, suggestive for a long-term acclimation response in fish held at low temperature. Overall feed efficiency was better at the lower temperature. A gradual decrease in growth rate and feed utilisation was seen at the higher temperature as the fish grew larger. The fish compensated for reduced energy density by increasing feed intake. At the higher temperature, better growth was found for fish fed the low-fat feeds, and there was also a tendency for improved growth when vegetable oil was used. Thus, there were no signs that vegetable oils are inferior to marine fish oil in promoting growth of Atlantic salmon parr in fresh water. Fish fed high fat feed were fatter than fish fed low fat feed, suggestive of lipostatic regulation of feed intake. Fat and protein digestibility were high at both 2°C and 8°C, although both fat and protein digestibility were lower at 2°C. At the lower temperature, increased dietary fat level increased the fat digestibility, and improved protein digestibility were seen when vegetable oil was included in the feed. Protein retention was higher at the higher temperature irrespective of feed treatment, indicating that proteins were both readily digested and converted into new tissues. The effects of feed treatment on low temperature acclimation responses were assessed from deposition of dietary fatty acids in fish tissues and from n-3 and n-6 essential fatty acid (EFA) budgets. Fatty acid composition of polar (membrane) and non-polar (storage) lipids in muscle, viscera and carcass were markedly influenced by the dietary oil, and non-polar lipids were more influenced than polar lipids. The retention n-6 EFAs was lower than for n- 3 EFAs, and was independent of temperature. The retention of n-3 EFAs retention was higher at the 2°C, especially amongst fish given the fish oil based diets. This may be a reflection of the importance of n-3 HUFAs during low temperature acclimation. However, the unsaturation (UFA:SFA ratio) of polar lipids was higher in fish fed the vegetable oils than for fish fed fish oil based feed. This may imply that vegetable oils produced fish that were better able to withstand exposure to low temperature, while having membrane lipids less susceptible to oxidative damage, due to the lower contents of n-3 HUFAs (mainly EPA and DHA). The six months feeding period in freshwater was followed by parr-smolt transformation, and a subsequent 42-days on-growing in seawater. Feed history during freshwater rearing influenced on-growth of smolts. A positive effect of using a vegetable oil was indicated, but this effect was only seen when there was a shift to a high-lipid fish oil based feed at the time of transfer to seawater. As such, it was evident that use of vegetable oils in freshwater feed did not interfere with low temperature acclimation or parr-smolt transformation of juvenile salmon, and subsequent on-growing in seawater was better when vegetable oil had been used in the feed. This indicates that fatty acid (lipid) requirement of Atlantic salmon are probably different in fresh water and seawater, and that these changes are linked to parr-smolt transformation. It could be speculated that that salinity may be more important than temperature as an environmental influence on the fatty acid requirements of Atlantic salmon. / Målet med dette studiet har vært å undersøke vanntemperaturens og saltholdighetens innvirkning på lipidernæringen hos parr og smolt av oppdrettet atlantisk laks (Salmo salar L.). Lakseparr ble holdt ved lav vanntemperatur (2ºC) i seks måneder mens de ble fôret med en av fire fôrtyper med ulike fettkilde (dvs. marin fiskeolje eller vegetabilsk olje) og ulik konsentrasjon (lav, 21% og høy, 34%). Responsene ved den lave temperaturen ble sammenlignet med responsene en fikk hos fisk holdt ved 8ºC i et full-faktorielt forsøksdesign. Fôrinntak og vekst ble opprettholdt ved 2ºC, men var lavere enn ved 8ºC. Over tid ble vekst og fôrutnyttelse forbedret, noe som indikerer en langtids akklimeringsrespons hos fisken ved den lave temperaturen. Totalt sett var utnyttelsen av fôret bedre ved den laveste temperaturen. En kunne observere en gradvis reduksjon i veksthastighet og fôrutnyttelse ved den høyeste temperaturen ettersom fisken ble større. Fisken kompenserte for lavere energitetthet i fôret ved å øke fôrinntaket. Ved den høyeste temperaturen var veksten bedre hos fisk fôret med lav-fett-fôrene. Det var også en tendens til forbedret tilvekst når vegetabilsk olje ble brukt. Det var ingen tegn til at vegetabilsk olje var dårligere enn marin fiskeolje til å fremme vekst hos lakseparr i ferskvann. Fisken som ble fôret med høy-fett-fôr ble fetere enn den som fikk lav-fett-fôr. Det indikerer lipostatisk regulering av fôrinntak. Fett- og proteinfordøyeligheten var høy både ved 2ºC og 8ºC, selv om både fett- og proteinfordøyeligheten var lavest ved 2ºC. Ved den laveste temperaturen, ga økt fettinnhold en forbedret fettfordøyelighet, og bruk av vegetabilsk olje i fôret ga bedre proteinfordøyelighet. Proteinretensjonen var høyere ved den høyeste temperaturen uavhengig av fôrtype, noe som indikerer at proteinet ble både lett fordøyd og omdannet til nytt vev. Effektene av fôrtype på akklimeringen til lav temperatur ble bestemt fra deponeringen av fettsyrer fra fôret i ulike vev og fra budsjetter for n-3 og n-6 essensielle fettsyrer (EFS). Fettsyresammensetningen i polare (membran) lipider og upolare (lagrings) lipider i muskel, innvoller og ’rest’ ble tydelig påvirket av oljene i fôret, og de upolare lipidene ble mer påvirket enn de polare lipidene. Retensjonen av n-6 EFS var lavere enn for n-3 EFS, og var uavhengig av temperatur. Retensjonen av n-3 EFS var høyere ved 2ºC, spesielt hos fisk som fikk et fiskeoljebasert fôr. Dette kan reflektere betydningen av n-3 HUFA fettsyrer i akklimeringen til lav temperatur. Imidlertid var de polare lipider hos fisk som ble gitt fôr med vegetabils olje, mer umettet (UFA:SFA forhold) enn hos fisk gitt fôr med marine fiskeoljer. Dette kan bety at vegetabilske oljer produserte fisk som var bedre i stand til å tåle eksponering til lav temperatur, samtidig som membranlipidene var mindre utsatt for oksidering som følge av et lavere innhold av n-3 HUFA fettsyrer (hovedsaklig EPA og DHA). Etter seks måneder i ferskvann ble fisken smoltifisert, etterfulgt av en 42-dagers periode i sjøvann. Fôrhistorie i ferskvannsfasen påvirket påvekst hos smolt. En positiv effekt av vegetabilsk olje ble funnet, men denne effekten ble bare funnet i grupper som hadde et skifte til et høy-fett-fiskeoljefôr ved overføring til sjøvann. Det var derfor tydelig at vegetabilsk olje ikke hadde negative konsekvenser for akklimering til lav temperatur eller for smoltifiseringen hos unglaks, og påfølgende tilvekst i sjøvann var bedre når vegetabilske oljer hadde blitt brukt. Dette indikerer at fettsyre (fett) behovet til atlantisk laks er forskjellig mellom ferskvann og sjøvann, og at forskjellene er knyttet til smoltifiseringen. Det kan derfor spekuleres i om saltholdigheten i miljøet er viktigere enn temperaturen i å bestemme fettsyrebehovet hos atlantisk laks. / Papers II and V reprinted with kind permission of Elsevier, sciencedirect.com.

<p>Programmed cell death (PCD) is a widely spread phenomenon among multi-cellular organisms. Without the deletion of cells no longer needed, the organism will not be able to develop in a predicted way. It is now belived that all cells have the capacity to self-destruct and that the survival of the cells is depending on the repression of this suicidal programme. PCD has turned out to show similarities in many different species and there are strong indications that the mechanisms running the programme might, at least in some parts, be evolutionarily conserced. PCD is a generic term for different programmes of cell destruction, such as apoptosis and autophagic PCD. An important tool to determine if a cell is undergoing PCD is the transmitting electron microscope. </p><p>The aims of my study were to find out if, and in what way, the suspensor and endosperm in <i>Vicia faba</i> (Broad bean), which are short-lived structures, undergoes PCD. The endosperm degradation preceed the suspensor cell death and they differ to some extent ultrastructurally. The cell death occurs in both tissues about 13-14 days after pollination when the embryo proper is mature enough to support itself. It was found that both tissues are committed to autophagic PCD, a cell death characteristic of conspicuous formations of autophagic vacuoles. It was shown by histochemical staining that acid phosphatases are accumulated in these vacuoles but are also present in the cytoplasm. These vacuoles are similar to autophagic vacuoles formed in rat liver cells, indicating that autophagy is a widely spread phenomenon. DNA fragmentation is the first visible sign of PCD in both tissues and it is demonstrated by a labelling technique (TUNEL). In the endosperm nuclei the heterochromatin subsequently appears in the form of a network, while in the suspensor it is more conspicuous, with heterochromatin that forms large electron dense aggregates located close to the nuclear envelope. </p><p>In the suspensor, the plastids develop into chromoplasts with lycopene crystals at the same time or shortly after DNA fragmentation. This is probably due to the fact that the suspensor plastids function as hormone producing organelles and support the embryo proper with indispensable growth factors. Later the embryo will be able to produce its own growth factors and the synthesis of these, in particular gibberelines, might be suppressed in the suspensor. The precursors can then be used for synthesis of lycopene instead. </p><p>Both the suspensor and endosperm are going through autophagic PCD, but the process differs in some respects. This is probably due the the different function of the two tissues, and that the signals that trigger the process presumably are different. The embryo proper is probably the source of the death signal affecting the suspensor. The endosperm, which has a different origin and function, might be controlling the death signal within its own cell. The death might in this case be related to the age of the cell.</p>

<p>Visual signals, used for communication both within and between species, vary immensely in the forms that they take. How is it that all this splendour has evolved in nature? Since it is the receiver’s preferences that cause selective pressures on signals, elucidating the mechanism behind the response of the signal receiver is vital to gain a closer understanding of the evolutionary process. In my thesis I have therefore investigated how receivers, represented by chickens, Gallus gallus domesticus, respond to different stimuli displayed on a peck-sensitive computer screen. According to the receiver bias hypothesis, animals and humans often express biases when responding to certain stimuli. These biases develop as by-products of how the recognition mechanism categorises and discriminates between stimuli. Since biases are generated from general stimulus processing mechanisms, they occur irrespective of species and type of signal, and it is often possible to predict the direction and intensity of the biases. One of the results from the experiments in my thesis demonstrates that similar experience in different species may generate similar biases. By giving chickens at least some of the experience of human faces as humans presumably have, the chickens subsequently expressed preferences for the same faces as a group of human subjects. Another kind of experience generated a bias for symmetry. This bias developed in the context of training chickens to recognise two mirror images of an asymmetrical stimulus. Untrained chickens and chickens trained on only one of the mirror images expressed no symmetry preferences. The bias produced by the training regime was for a specific symmetrical stimulus which had a strong resemblance to the familiar asymmetrical exemplar, rather than a general preference for symmetry. A further kind of experience, training chickens to respond to some stimuli but not to others, generated a receiver bias for exaggerated stimuli, whereas chickens trained on reversed stimuli developed a bias for less exaggerated stimuli. To investigate the potential of this bias to drive the evolution of signals towards exaggerated forms, a simplified evolutionary process was mimicked. The stimuli variants rejected by the chickens were eliminated, whereas the selected forms were kept and evolved prior to the subsequent display. As a result, signals evolved into exaggerated forms in all tested stimulus dimensions: length, intensity and area, despite the inclusion of a cost to the sender for using increasingly exaggerated signals. The bias was especially strong and persistent for stimuli varying along the intensity dimension where it remained despite extensive training. All the results in my thesis may be predicted by the receiver bias hypothesis. This implies that biases, developed due to stimuli experience, may be significant mechanisms driving the evolution of signal form.</p>

<p>In externally fertilising fishes, various factors in the surrounding environment may influence the viability of the sperm and eggs, thus determining the success of reproduction. In this thesis, the influence of salinity and ovarian fluid on sperm motility has been investigated in three Gasterosteiform fishes.</p><p>The three-spined stickleback, <i>Gasterosteus aculeatus</i>, has successfully invaded fresh water and differs from most other fishes in its ability to spawn in waters of all salinities. Our results show that sperm of the three-spined is strongly stimulated by the ovarian fluid surrounding the eggs. In fresh water, where the period of motility is only about a minute, ovarian fluid prolongs motility to last several hours. We show that this effect is due to fluid’s ionic content and that the fluid remains in the nest, surrounding the eggs, for a prolonged time due to the proteins and/or other macromolecules in the fluid. Our results explain how successful spawning can occur in fresh water despite that it takes several minutes for all three-spined stickleback eggs to be fertilised. The stimulating effect of ovarian fluid may be one of the factors that have enabled the originally marine three-spined stickleback to colonise fresh water.</p><p>The fifteen-spined stickleback, <i>Spinachia spinachia</i>, is exclusively marine. We found their sperm motility to be good in seawater, reduced in brackish water, and non-existent in freshwater. The presence of ovarian fluid made no difference in any salinity, a factor that might have contributed to their inability to colonise fresh water. Being regarded as a primitive member of the stickleback family, the lack of response to ovarian fluid suggests that this is not a primitive trait among the sticklebacks.</p><p>The male straight-nose pipefish, <i>Nerophis ophidion </i>carries the eggs attached to its ventral surface. Fertilisation has previously been suggested to be external, but our results show that their sperm are not motile in seawater alone, but in a mixture of seawater and ovarian fluid. This result, together with the finding of some sperm in the female genital area, and that the sperm head is elongated, suggests that the fertilisation in the straight-nose pipefish occurs in close proximity with the eggs and ovarian fluid. This could then explain why the straight-nose pipefish has minute testes and complete confidence of paternity.</p>

<p>Many environmental pollutants, heavy metals and polyaromatic hydrocarbons (PAHs) among them, are toxic by oxidative stress. Oxidative stress may be defined as a state in an organism when its inherent capacity to handle oxyradicals is surpassed, and it may result in peroxidation of lipids, and damage to proteins and DNA. Thus, genotoxic stress may follow oxidative stress.</p><p>Little is known about the effects of genotoxic stress in invertebrates, although the occurrence of tumors has been known for quite some time, in bivalve mollusks at least since the 1960s. Less dramatic manifestations of genotoxic stress may include impaired enzyme functions, altered protein turnover, with possible effects on physiological processes. Keys to a better understanding of genotoxic stress are the proteins involved in the regulation of the cell-cycle and DNA repair. Virtually nothing is known about these proteins in mussels. The work presented in the papers I, II, and IV aimed to give a first insight into how the blue mussel responds to genotoxic stress following exposure to the polyaromatic hydrocarbon (PAH) benzo[a]pyrene (B[a]P), PAHs in petrochemical pollution, copper (Cu) or cadmium (Cd), all substances known to enhance formation of oxyradicals. PAHs may also be genotoxic by formation of DNA adducts. The cell-cycle and DNA repair proteins studied were the proliferating cell nuclear antigen (PCNA) and the retinoblastoma protein 110 (Rb110). The first is involved in DNA repair and cell proliferation; the second at the G1 checkpoint of the cell-cycle. We showed that the PCNA is a potential marker of genotoxic response (DNA repair, and/or cell proliferation) to PAHs (papers I and IV) and cadmium (paper II). Furthermore, cadmium may possibly elicit a cell-cycle stop mediated by the Rb110 (the paper II). Based on these cell-cycle and DNA repair proteins, the genotoxic responses in blue mussels seem to be similar to that in vertebrates.</p><p>Markers of general stress or oxidative stress were used in all studies. The applicability of the general stress marker heat shock proteins (HSP70 and HSP60) (papers I and IV), the polyglycoprotein (P-gp) (paper I), a marker of exposure to planar organic compounds, and markers of oxidative stress, such as the antioxidant defense enzyme copper/zinc-superoxide dismutase (Cu/Zn-SOD) (paper II), and the oxidative protein modifications protein carbonyls and disulfides (papers III and IV) were tested in various situations. In accordance with results by others, my studies have shown that HSPs, which formerly were considered as universal stress markers, are not always applicable, as their expression is affected by factors that are difficult to control (papers I). I found that the P-gp can be used as a marker of B[a]P exposure in Baltic Sea blue mussels (paper I). In paper II, I reported that the Cu/Zn-SOD was up-regulated in response to Cd exposure, a clear indication of oxidative stress that was also manifested as a response in the studied cell-cycle and DNA repair proteins. Protein carbonyls were successfully used in the papers III and IV to indicate oxidative stress. In paper III, I also investigated the potential of diagonal gels as a tool for identification of protein disulfides in protein expression signatures (PESs). The diagonal gels hold a good potential for identification of novel and prime targets of oxidative stress.</p><p>My work was performed as short-term laboratory studies, in vivo, in blue mussels from the Baltic Sea, and as a one year long field experiment with Icelandic blue mussels in a tidal system. The idea was to use blue mussels that were already physiologically challenged (by osmotic stress, or alternating aerobic and anaerobic metabolism), to see how they responded to additional stress in the form of toxicants capable of inducing oxidative and genotoxic stress. Most of the work on biochemical endpoints in blue mussels published so far was done on blue mussels from fully marine environments, and without consideration to the effect of tide.</p>

No description available.

<p>The present study assessed the taste responsiveness of four female spider monkeys (<em>Ateles geoffroyi</em>) to the 20 proteinogenic amino acids and determined taste preference thresholds for Glycine and L-Proline. To this end a two-bottle preference test of brief duration (1min) was employed. When presented at a concentration of 200 mM, the spider monkeys significantly preferred three proteinogenic amino acids (Glycine, L-Proline and L-Alanine) over fresh water whereas four other amino acids were significantly rejected (L-Tyrosine, L-Valine, L-Cysteine and L-Isoleucine). At a concentration of 100 mM, seven proteinogenic amino acids were significantly preferred (Glycine, L-Proline, L-Alanine, L-Glutamic acid, L-Aspartic acid, L-Serine and L-Lysine) whereas one was significantly rejected (L-Tryptophan). A comparison between the taste qualities of the amino acids as described by humans and taste preference/rejection responses observed with the spider monkeys suggests a fairly high degree of agreement in perception of these taste substances between the two species. When given the choice between fresh water and defined concentrations of two amino acids that taste sweet to humans the spider monkeys were found to significantly discriminate concentrations as low as 10-50 mM of Glycine and 10-40 mM of L-Proline from the solvent. This suggests that spider monkeys are similar in their taste sensitivity for Glycine and L-Proline compared to humans and slightly more sensitive compared to mice.</p>