Studies of new inorganic species using relativistic quantum chemistry

In the present work the methods of relativistic quantum chemistry have been applied to a number of small systems containing heavy elements, for which relativistic effects are important. First, a thorough introduction of the methods used is presented. This includes some of the general methods of computational chemistry and a special section dealing with how to include the effects of relativity in quantum chemical calculations. Second, after this introduction the results obtained are presented. Investigations on high-valent mercury compounds are presented and new ways to synthesise such compounds are proposed. The methods described were applied to certain systems containing short Pt-Tl contacts. It was possible to explain the interesting bonding situation in these compounds. One of the most common actinide compounds, uranium hexafluoride was investigated and a new picture of the bonding was presented. Furthermore the rareness of uranium-cyanide compounds was discussed. In a foray into the chemistry of gold, well known for its strong relativistic effects, investigations on different gold systems were performed. Analogies between Au$^+$ and platinum on one hand and oxygen on the other were found. New systems with multiple bonds to gold were proposed to experimentalists. One of the proposed systems was spectroscopically observed shortly afterwards. A very interesting molecule, which was theoretically predicted a few years ago is WAu$_{12}$. Some of its properties were calculated and the bonding situation was discussed. In a further study on gold compounds it was possible to explain the substitution pattern in bis[phosphane-gold(I)] thiocyanate complexes. This is of some help to experimentalists as the systems could not be crystallised and the structure was therefore unknown. Finally, computations on one of the heaviest elements in the periodic table were performed. Calculation on compounds containing element 110, darmstadtium, showed that it behaves similarly as its lighter homologue platinum. The extreme importance of relativistic effects for these systems was also shown.

A quantum chemical investigation of the metal centres in cytochrome c oxidase

Quantum effects are often of key importance for the function of biological systems at molecular level. Cellular respiration, where energy is extracted from the reduction of molecular oxygen to water, is no exception. In this work, the end station of the electron transport chain in mitochondria, cytochrome c oxidase, is investigated using quantum chemical methodology. Cytochrome c oxidase contains two haems, haem a and haem a3. Haem a3, with its copper companion, CuB, is involved in the final reduction of oxygen into water. This binuclear centre receives the necessary electrons from haem a. Haem a, in turn, receives its electrons from a copper ion pair in the vicinity, called CuA. Density functional theory (DFT) has been used to clarify the charge and spin distributions of haem a, as well as changes in these during redox activity. Upon reduction, the added electron is shown to be evenly distributed over the entire haem structure, important for the accommodation of the prosthetic group within the protein. At the same time, the spin distribution of the open-shell oxidised state is more localised to the central iron. The exact spin density distribution has been disputed in the literature, however, different experiments indicating different distributions of the unpaired electron. The apparent contradiction is shown to be due to the false assumption of a unit amount of unpaired electron density; in fact, the oxidised state has about 1.3 unpaired electrons. The validity of the DFT results have been corroborated by wave function based coupled cluster calculations. Point charges, for use in classical force field based simulations, have been parameterised for the four metal centres, using a newly developed methodology. In the procedure, the subsystem for which point charges are to be obtained, is surrounded by an outer region, with the purpose of stabilising the inner region, both electronically and structurally. Finally, the possibility of vibrational promotion of the electron transfer step between haem a and a3 has been investigated. Calculating the full vibrational spectra, at DFT level, of a combined model of the two haems, revealed several normal modes that do shift electron density between the haems. The magnitude of the shift was found to be moderate, at most. The proposed mechanism could have an assisting role in the electron transfer, which still seems to be dominated by electron tunnelling.

Radikalcyklisering vid syntes av polycykliska indoler och pyrroler

I de senaste två decennierna har radikalcyklisering, intramolekylär radikaladdition, utvecklats till en viktig syntesmetod för polycykliska indoler och pyrroler. De erhållna produktmolekylerna eller deras derivat är ofta naturliga eller syntetiska alkaloider som väckt biologiskt eller medicinskt intresse. Avhandlingen behandlar både intramolekylära radikaladditioner av pyrrolyl-, indolyl- eller indolylacylradikaler till -bindningar och intramolekylära additioner av flera olika radikaler till indolens eller pyrrolens -system. Också cykliseringar som delreaktioner i radikalkaskader behandlas. Radikalreaktioner kan släckas både oxidativt och reduktivt. För att bibehålla heteroarenens aromaticitet måste cykliseringar till pyrrol- eller indolringen släckas oxidativt. Oxidativa radikaladditioner till aromater benämns homolytiska aromatiska substitutioner. Det finns olika sätt att erhålla en reaktantradikal från en radikalprekursor. I vissa fall har radikalprekursorn en mycket labil bindning som kan brytas fotokemiskt eller med hjälp av en initiator. Till exempel kol-svavelbindningen av en O-etyl-S-alkylxanthat kan brytas på detta sätt. Ofta används dock en radikalmediator för att bilda en reaktantradikal från dess prekursor. Mediatorer är ofta föreningar, som under reaktionsförhållandena själv bildar radikaler med en stor affinitet för en prekursors specifika atom eller atomgrupp vilken abstraheras. Således fungerar mediatorn som mellanhand vid bildning av reaktantradikalen. Exempel på mediatorer av detta slag som använts vid syntes av polycykliska pyrroler och indoler är tributyltennhydrid, hexabutylditenn, tris(trimetylsilyl)silan, tributylgermaniumhydrid, dicumylperoxid, trietylboran, natriumarensulfinater (med ättiksyra) och Se-fenyl-p-toluenselenosulfonat. Också dimetylsulfoxid kan ses som mediator då den bildar metylradikaler vid Fentonreaktion i lösningsmedlet. Övergångsmetallsalter kan även bilda reaktantradikalen från prekursorn genom enelektronoxidationer eller -reduktioner. Vid syntes av polycykliska pyrroler och indoler har reaktantradikalen bildats genom enelektronoxidationer med Mn(OAc)3 eller Ag2+ (Miniscireaktion) och elektronreduktioner med ett Ni(I)-komplex eller SmI2. Avhandlingen är indelad enligt reagenset eller reagensen, som åstadkommer bildning av reaktantradikalen vid syntes av polycykliska indoler och pyrroler. Cirka hälften av avhandlingen behandlar tributyltennhydridmedierade cykliseringar då reagenset trots dess toxicitet är det överlägset mest använda. Avhandlingen diskuterar mekanismen för bildning av reaktantradikalen från prekursorn, cykliseringen och dess möjliga regioselektivitet, andra radikalreaktioner vid radikalkaskader och hur produktradikalen släcks.

Aza-Wittigringslutningar vid syntes av sammansmälta kväveheterocykler

Denna pro gradu avhandling är en litteraturstudie av intramolekylära aza-Wittigringslutningar vid syntes av sammansmälta kväveheterocykler. I arbetet behandlas material huvudsakligen från 1980 och framöver. Aza-Wittigreaktionen påminner om den analoga Wittigreaktionen. Aza-Wittigreaktioner har nästan uteslutande gjorts mellan karbonylgrupper och iminofosforaner. Reaktionsmekanismen sker enligt en tvåstegsaddition, som inleds av iminokvävets nukleofila attack till karbonylkolet och avslutas av att en zwitterjonisk betain bildar en azoxafosfetanintermediär. Intermediären sönderfaller spontant till en iminoprodukt och fosfinoxid. Reaktionen görs ofta under milda betingelser d.v.s. vid rumstemperatur och dessutom utan dyr arbetsutrustning Ett vanligt sätt att framställa iminofosforanen är från azid genom Staudingerreaktion och ofta kombineras Staudinger- och aza-Wittigreaktionerna så att iminofosforanen inte isoleras före ringslutningen. Alla andra ringslutningsreaktioner än aza-Wittig, såsom elektrocykliska ringslutningar, har uteslutits ur detta arbete. Materialet i litteraturstudien har indelats enligt vilken typ av karbonylgrupp iminofosforanen reagerar med. På så vis åskådliggörs hurudana typiska produktmolekyler som erhållits med ringslutning till en viss typ av karbonylgrupp. Det har visat sig att det är förmånligt om karbonylkolet har elektronunderskott och iminofosforanens kväve har elektronöverskott. Den ringslutande molekylens entropi och närbelägna substituenters elektroniska och steriska natur samt produktmolekylens termodynamiska fördelaktighet inverkar tillsammans på reaktionens gång. Ifall reaktionen förväntas ske långsamt är det bättre att använda sig av alkyliminofosforaner än aryliminofosforaner. Valet av lösningsmedel har nästan uteslutande lämnats oförklarat i de behandlade publikationerna men i de flesta fall har ortoxylen eller toluen varit goda lösningsmedel. Oönskad tetrazolbildning av aziden kan minimeras genom användning av opolärt lösningsmedel. Likaså kan förmånligt placerade kväveskyddsgrupper hindra intramolekylära vätebindningar. På senare tid har aza-Wittigreaktionen allt mera tillämpats vid framställning av farmakologiska produkter, vilket ökat intresset för att framställa stora mängder närbesläktade produktmolekyler. Dylika molekylbibliotek har med fördel framställts i fastfas varvid reningen av produkten underlättats märkbart. Ett nytt område inom aza-Wittigsyntetiken är asymmetriska reaktioner, vilka säkert kommer att få mera uppmärksamhet i framtiden. I denna litteraturstudie framkom det att många av de utförda synteserna på området kunde upprepas med större variation och systematik gällande reagens och reaktionsbetingelser.

Förutsättningarna för psykiatrisk vård oberoende av patientens vilja och patientens rättsskydd vid fattandet av vårdbeslutet

I arbetet analyseras de i mentalvårdslagen (1990/1116) stadgade förutsättningarna för psykiatrisk sjukhusvård oberoende av patientens vilja gällande myndiga patienter för vilka inte har utsetts en intressebevakare före fattandet av vårdbeslutet, samt bakgrunden till och en del av de svårigheter som förknippas med denna form av vård och härtill anknutet beslutsfattande. Problemen tillspetsas framförallt i situationer av intressekonflikt mellan patientens intressen respektive samhällets intressen. Utgångspunkten ligger främst i finländsk mentalvårdslagstiftning och rättspraxis, men för att på ett ändamålsenligt sätt kunna redogöra för bakgrunden till och förutsättningarna för dylikt förvaltningsrättsligt beslutsfattande görs även relevanta kopplingar till medicinska (psykiatriska) yrkesetiska riktlinjer och mentalvårdslagstiftning inom övriga Norden. Analysen omfattar även den Europeiska människorättsdomstolens praxis i fall som gäller frihetsberövande på basis av psykiatrisk vård, närmare bestämt artikel 5 (1)(e) i den europeiska människorättskonventionen. Patientens självbestämmanderätt, frihet och integritet är utgångspunkterna för alla slags vårdförhållanden. Dessa inbegriper bl.a. frivillighet och informerat samtycke då en person söker vård. Möjligheten att förordna en person till psykiatrisk vård oberoende av dennes vilja är ett lagstadgat undantag till dessa principer. Beslutsfattandet är bundet till strikta lagstadgade förutsättningar, vilkas bedömning kräver juridisk, men framförallt medicinsk kunskap, vilket också skapar gränser och utmaningar för de yrkespersoner som arbetar med dylika ärenden. Kombinationen av psykiatri, etik och juridik är nödvändig, men inte alltid enkel att göra, vilket märks inte minst på terminologin som tillämpas i mentalvårdslagstiftningen. I arbetet analyseras en del av den terminologi som tillämpas inom finsk och övrig nordisk mentalvårdslagstiftning. Syftet är att visa att definitionerna, tolkningarna, terminologin och synsättet på psykisk ohälsa som tillämpas inom den finländska mentalvårdslagstiftningen jämförelsevis kanske inte är de mest lämpliga eller tidsenliga. En annan svår uppgift, som framförallt lagstiftaren ställ(t)s inför, är utformningen av mentalvårdslagstiftning som är tillräckligt flexibel för att tillåta beaktande av särdragen i varje enskilt ärende, men som samtidigt är strikt nog för att förhindra godtycke och missbruk. En person som lider av allvarlig psykisk ohälsa befinner sig oftast i en ytterst utsatt position, och är ofta begränsat eller inte alls kapabel att göra en korrekt bedömning av sig själv och sin situation. Således sker den starka betoningen av patientens självbestämmanderätt på både gott och ont. Det är kanske inte alltid i en psykiatrisk patients bästa att få bestämma själv, vilket också är en av frågorna som omfattas av analysen i arbetet. Eftersom det psykiatriska vårdbeslutet till karaktären är ett (skriftligt) förvaltningsbeslut, skiljer det sig samtidigt från övrigt beslutsfattande inom vårdsektorn, vilket till största delen utgör faktisk förvaltningsverksamhet. För patienten innebär vårdbeslutet också ett administrativt frihetsberövande. Ingreppet i patientens grundläggande fri- och rättigheter är särskilt stort och upplevs ofta som mycket kränkande, och därför ställs särskilt strikta krav på iakttagande av det lagstadgade beslutsförfarandet och vårdförutsättningarna samt tillgodoseendet av patientens rättsskydd. Den offentliga hälso- och sjukvården är verksamhet som är underställd den offentliga förvaltningen, vilket innebär att de allmänna förvaltningsrättsliga rättsskyddsgarantierna är tillämpliga. I och med vårdbeslutets karaktär av förvaltningsbeslut, kan ändring i beslutet sökas genom besvär hos förvaltningsdomstolen. Dessa är också några av de frågor som behandlas i arbetet.

Viljan visar vägen till identiteten : Berättelsetyper och teman i livsberättelser av kvinnliga teologer i Svenskfinland

Forskningens utgångspunkt var att tillföra information om kvinnliga teologers liv i Svenskfinland under en period då kyrkan hade omdefinierat sin syn på kvinnor som präster. Till forskningens intresseområden hörde frågan om hur situationen hade påverkat kvinnors motivation att välja teologiska studier och yrken samt hur situationen hade inverkat på kvinnliga teologer i arbetslivet. Forskningens uppgift är att ur ett identitetsperspektiv undersöka målgruppens egna skildringar av livet som kvinnlig teolog i Svenskfinland. Forskningsfrågan delades in i två delfrågor: 1)Hur har kvinnliga teologer kommit att välja studier, yrken och arbetsplats? 2)Vad har kvinnliga teologer upplevt i sina studier och arbetsliv? Forskningens material samlades in hösten 2003 genom en förfrågan per brev och genom en tidningsnotis i tidningen Kyrkpressen. Materialet bestod av livsberättelser som kvinnliga teologer i olika yrkesgrupper hade skrivit utgående ifrån rubriken ”Mitt liv som kvinnlig teolog i Svenskfinland”. Cirka 250 kvinnor hade avlagt teologisk examen på svenska i Finland. Antalet personer som deltog i undersökningen med sin livsberättelse var 27. Materialet analyserades kvalitativt och induktivt med en narrativ analys som tog fasta på teman och berättelsetyper i olika livsskeden: val av studier, studietid, val av karriär och erfarenheter från arbetslivet. Analysresultatet var att studievalets beskrivning kunde tolkas som en valsituation där egenskaper jämfördes med yrkesrollen, som en socialisationsprocess, som ett alternativ till tidigare studieinriktning eller som en process där kvinnoprästdiskussioner, intresse för teologi och teologuppgifter fick informanten att välja teologin. Teman från studietiden handlade om studiers fördröjning, om yrkesinriktning, om studier som förberedelse för arbetslivet och om kvinnoprästdiskussionens inverkan på yrkesinriktningen. Val av arbetsplatser och yrken beskrevs utgående ifrån kvinnliga teologers förändrade position, moderskapets inverkan på karriären, en strävan att hitta en arbetsplats som passade informanten, erfarenheter från en enda arbetsplats och karriärsbyte. Lektorer tog fasta på välsignelseaktens betydelse, kyrkoherdens stora inflytande på arbetets karaktär samt hur situationen förändrades då kvinnor tilläts bli präster. För en del präster innebar prästrollen att andra människor betonade att de var kvinnor. Några informanter hade behov av stöd både från Borgå stifts ledning och från andra kvinnliga präster under den första tiden med kvinnliga präster. Till en början upplevdes ledningens stöd inte alltid som tillräckligt men det förbättrades med tiden. Informanterna berättade inte så mycket om läraryrket. Inom forskning verkade teologtiteln vara naturlig, medan informanter med erfarenhet av annat än teologyrken ibland hade stött på reaktioner på sitt yrkesval eller sin arbetsroll. Finlandssvenskheten upplevdes av olika informanter både som tryggt och inskränkt. Eventuella kontakter till finska stift upplevdes positivt även om det egna sammanhanget upplevdes som viktigt. Trivsel på arbetsplatsen orsakades av subjektiva belöningar och i en del fall av att arbetet motsvarade informantens yrkesinriktning. Att vara kvinnlig teolog innebar ibland att informantens yrkesval tolkades av andra som ett ställningstagande för någon ideologi i kvinnoprästfrågan.

Större frihet - bättre lokalt anpassad service? : Förvaltningsreformer och kommunernas service för utvecklingsstörda 1994-2000

In the beginning of the 1990s the legislation regarding the municipalities and the system of central government transfers were reformed in Finland. This resulted in a move from detailed governmental control to increased municipal autonomy. The purpose of this decentralization was to enable the municipalities to better adapt their administration and service supply to local needs. The aim of this study was to explore the effects of the increased municipal autonomy on the organization of services for people with intellectual disabilities. Did the increased autonomy cause the municipalities to alter their service supply and production and did the services become more adapted to local needs? The data consists of statistical information on service use and production, and also of background data such as demographics, economics and political elections on 452 municipalities in Finland from the years 1994 and 2000. The methods used are cluster analysis, discriminant analysis and factor analysis. The municipalities could be grouped in two categories: those which offered mainly one kind of residential services and others which had more varied mixes of services. The use of institutional care had decreased and municipalities which used institutional care as their primary form of service were mostly very small municipalities in 2000. The situation had changed from 1994, when institutional care was the primary service for municipalities of all sizes. Also the service production had become more differentiated and the municipalities had started using more varied ways of production. More municipalities had started producing their own services and private production had increased as well. Furthermore, the increase in local autonomy had opened up possibilities for local politics to influence both the service selection and methods of production. The most significant motive for changes in the service structure was high unemployment and an increasing share of elderly people in the population, particularly in sparsely populated areas. Municipalities with a low level of resources had made more changes in their service organization while those with more resources had been able to carry on as before. Key words: service structure, service for people with intellectual disabilities, municipalities, contingency theory, New Public Management

Redox-linked proton transfer by cytochrome c oxidase

The respiratory chain is found in the inner mitochondrial membrane of higher organisms and in the plasma membrane of many bacteria. It consists of several membrane-spanning enzymes, which conserve the energy that is liberated from the degradation of food molecules as an electrochemical proton gradient across the membrane. The proton gradient can later be utilized by the cell for different energy requiring processes, e.g. ATP production, cellular motion or active transport of ions. The difference in proton concentration between the two sides of the membrane is a result of the translocation of protons by the enzymes of the respiratory chain, from the negatively charged (N-side) to the positively charged side (P-side) of the lipid bilayer, against the proton concentration gradient. The endergonic proton transfer is driven by the flow of electrons through the enzymes of the respiratory chain, from low redox-potential electron donors to acceptors of higher potential, and ultimately to oxygen. Cytochrome c oxidase is the last enzyme in the respiratory chain and catalyzes the reduction of dioxygen to water. The redox reaction is coupled to proton transport across the membrane by a yet unresolved mechanism. Cytochrome c oxidase has two proton-conducting pathways through which protons are taken up to the interior part of the enzyme from the N-side of the membrane. The K-pathway transfers merely substrate protons, which are consumed in the process of water formation at the catalytic site. The D-pathway transfers both substrate protons and protons that are pumped to the P-side of the membrane. This thesis focuses on the role of two conserved amino acids in proton translocation by cytochrome c oxidase, glutamate 278 and tryptophan 164. Glu278 is located at the end of the D-pathway and is thought to constitute the branching point for substrate and pumped protons. In this work, it was shown that although Glu278 has an important role in the proton transfer mechanism, its presence is not an obligatory requirement. Alternative structural solutions in the area around Glu278, much like the ones present in some distantly related heme-copper oxidases, could in the absence of Glu278 support the formation of a long hydrogen-bonded water chain through which proton transfer from the D-pathway to the catalytic site is possible. The other studied amino acid, Trp164, is hydrogen bonded to the ∆-propionate of heme a3 of the catalytic site. Mutation of this amino acid showed that it may be involved in regulation of proton access to a proton acceptor, a pump site, from which the proton later is expelled to the P-side of the membrane. The ion pair that is formed by the ∆-propionate of heme a3 and arginine 473 is likely to form a gate-like structure, which regulates proton mobility to the P-side of the membrane. The same gate may also be part of an exit path through which water molecules produced at the catalytically active site are removed towards the external side of the membrane. Time-resolved optical and electrometrical experiments with the Trp164 to phenylalanine mutant revealed a so far undetected step in the proton pumping mechanism. During the A to PR transition of the catalytic cycle, a proton is transferred from Glu278 to the pump site, located somewhere in the vicinity of the ∆-propionate of heme a3. A mechanism for proton pumping by cytochrome c oxidase is proposed on the basis of the presented results and the mechanism is discussed in relation to some relevant experimental data. A common proton pumping mechanism for all members of the heme-copper oxidase family is moreover considered.

Traditional medicinal uses and biological activities of some plant extracts of African Combretum Loefl., Terminalia L. and Pteleopsis Engl. species

In Africa various species of Combretum, Terminalia and Pteleopsis are used in traditional medicine. Despite of this, some species of these genera have still not been studied for their biological effects to validate their traditional uses. The aim of this work has been to document the ethnomedicinal uses of several species of Combretum and Terminalia in Mbeya region, south-western Tanzania, and to use this information for finding species with good antimicrobial and cytotoxic potential. During a five weeks expedition to Tanzania in spring 1999 sixteen different species of Combretum and Terminalia, as well as Pteleopsis myrtifolia were collected from various locations in the districts of Mbeya, Iringa and Dar-es-Salaam. Traditional healers in seven different villages in the Mbeya region were interviewed in Swahili and Nyakyusa on the medicinal uses of Combretum and Terminalia species shown to them. A questionnaire was used during the interviews. The results of the interviews correlated well between different villages, the same species being used in similar ways in different villages. Of the ten species shown to the healers six were frequently used for treatment of skin diseases, bacterial infections, diarrhea, oedema and wounds. The dried plants were most commonly prepared into hot water decoctions or mixed into maize porridge, Ugali. Infusions made from dried or fresh plant material were also common. Wounds and topical infections were treated with ointments made from the dried plant material mixed with sheep fat. Twenty-one extracts of six species of Combretum and four of Terminalia, collected from Tanzania, were screened for their antibacterial effects against two gram-negative and five gram-positive bacteria, as well as the yeast, Candida albicans, using an agar diffusion method. Most of the screened plants showed substantial antimicrobial activity. A methanolic root extract of T. sambesiaca showed the most potent antibacterial effects of all the plant species screened, and gave a MIC value of 0.9 mg/ml against Enterobacter aerogenes. Also root extracts of T. sericea and T. kaiserana gave excellent antimicrobial effects, and notably a hot water extract of T. sericea was as potent as extracts of this species made from EtOH and MeOH. Thus, the traditional way of preparing T. sericea into hot water decoctions seems to extract antimicrobial compounds. Thirty-five extracts of five species of Terminalia, ten of Combretum and Pteleopsis myrtifolia were screened for their antifungal effects against five species of yeast (Candida spp.) and Cryptococcus neoformans. The species differed from each other to their antifungal effects, some being very effective whereas others showed no antifungal effects. The most effective extracts showed antifungal effects comparable to the standard antibiotics itraconazol and amphotericin B. Species of Terminalia gave in general stronger antifungal effects than those of Combretum. The best effects were obtained with methanolic root extracts of T. sambesiaca, T. sericea and T. kaiserana, and this investigation indicates that decoctions of these species might be used for treatment of HIV-related fungal infections. Twenty-seven crude extracts of eight species of Combretum, five of Terminalia and Pteleopsis myrtifolia were evaluated for their cytotoxic effects against human cancer cell lines (HeLa, cervical carcinoma; MCF 7, breast carcinoma, T 24 bladder carcinoma) and one endothelial cell line (BBCE, bovine brain capillary endothelial cells). The most outstanding effects were obtained with a leaf extract of Combretum fragrans, which nearly totally inhibited the proliferation of T 24 and HeLa cells at a concentration of 25 ug/ml and inhibited 60 % of the growth of the HeLa cells at a concentration of 4.3 ug/ml. The species of Terminalia were less cytotoxically potent than the Combretum species, although T. sericea and T. sambesiaca gave good cytotoxic effects (< 30 % proliferation). In summary this study indicates that some of the species of Terminalia, Combretum and Pteleopsis, used in Tanzanian traditional medicine, are powerful inhibitors of both microbial and cancer cell growth. In depth studies would be needed to find the active compounds behind these biological activities.

Population dynamics of blue mussels in a variable environment at the edge of their range

Spatial and temporal variation in the abundance of species can often be ascribed to spatial and temporal variation in the surrounding environment. Knowledge of how biotic and abiotic factors operate over different spatial and temporal scales in determining distribution, abundance, and structure of populations lies at the heart of ecology. The major part of the current ecological theory stems from studies carried out in central parts of the distributional range of species, whereas knowledge of how marginal populations function is inadequate. Understanding how marginal populations, living at the edge of their range, function is however in a key position to advance ecology and evolutionary biology as scientific disciplines. My thesis focuses on the factors affecting dynamics of marginal populations of blue mussels (Mytilus edulis) living close to their tolerance limits with regard to salinity. The thesis aims to highlight the dynamics at the edge of the range and contrast these with dynamics in more central parts of the range in order to understand the potential interplay between the central and the marginal part in the focal system. The objectives of the thesis are approached by studies on: (1) factors affecting regional patterns of the species, (2) long-term temporal dynamics of the focal species spaced along a regional salinity gradient, (3) selective predation by increasing populations of roach (Rutilus rutilus) when feeding on their main food item, the blue mussel, (4) the primary and secondary effects of local wave exposure gradients and (5) the role of small-scale habitat heterogeneity as determinants of large-scale pattern. The thesis shows that populations of blue mussels are largely determined by large scale changes in sea water salinity, affecting mainly recruitment success and longevity of local populations. In opposite to the traditional view, the thesis strongly indicate that vertebrate predators strongly affect abundance and size structure of blue mussel populations, and that the role of these predators increases towards the margin where populations are increasingly top-down controlled. The thesis also indicates that the positive role of biogenic habitat modifiers increases towards the marginal areas, where populations of blue mussels are largely recruitment limited. Finally, the thesis shows that local blue mussel populations are strongly dependent on high water turbulence, and therefore, dense populations are constrained to offshore habitats. Finally, the thesis suggests that ongoing sedimentation of rocky shores is detrimental for the species, affecting recruitment success and post-recruit survival, pushing stable mussel beds towards offshore areas. Ongoing large scale changes in the Baltic Sea, especially dilution processes with attendant effects, are predicted to substantially contract the distributional range of the mussel, but also affect more central populations. The thesis shows that in order to understand the functioning of marginal populations, research should (1) strive for multi-scale approaches in order to link ecosystem patterns with ecosystem processes, and (2) challenge the prevailing tenets that origin from research carried out in central areas that may not be valid at the edge.

From actin monomers to bundles: The roles of twinfilin and α-actinin in Drosophila melanogaster development

The actin cytoskeleton is essential for a large variety of cell biological processes. Actin exists in either a monomeric or a filamentous form, and it is very important for many cellular functions that the local balance between these two actin populations is properly regulated. A large number of proteins participate in the regulation of actin dynamics in the cell, and twinfilin, one of the proteins examined in this thesis, belongs to this category. The second level of regulation involves proteins that crosslink or bundle actin filaments, thereby providing the cell with a certain shape. α-Actinin, the second protein studied, mainly acts as an actin crosslinking protein. Both proteins are conserved in organisms ranging from yeast to mammals. In this thesis, the roles of twinfilin and α-actinin in development were examined using Drosophila melanogaster as a model organism. Twinfilin is an actin monomer binding protein that is structurally related to cofilin. In vitro, twinfilin reduces actin polymerisation by sequestering actin monomers. The Drosophila twinfilin (twf) gene was identified and found to encode a protein functionally similar to yeast and mammalian twinfilins. A strong hypomorphic twf mutation was identified, and flies homozygous for this allele were viable and fertile. The adult twf mutant flies displayed reduced viability, a rough eye phenotype and severely malformed bristles. The shape of the adult bristle is determined by the actin bundles that are regularly spaced around the perimeter of the developing pupal bristles. Examination of the twf pupal bristles revealed an increased level of filamentous actin, which in turn resulted in splitting and displacement of the actin bundles. The bristle defect was rescued by twf overexpression in developing bristles. The Twinfilin protein was localised at sites of actin filament assembly, where it was required to limit actin polymerisation. A genetic interaction between twinfilin and twinstar (the gene encoding Cofilin) was detected, consistent with the model predicting that both proteins act to limit the amount of filamentous actin. α-Actinin has been implicated in several diverse cell biological processes. In Drosophila, the only function for α-actinin yet known is in the organisation of the muscle sarcomere. Muscle and non-muscle cells utilise different α-actinin isoforms, which in Drosophila are produced by alternative splicing of a single gene. In this work, novel α-actinin deletion alleles, including ActnΔ233, were generated, which specifically disrupted the transcript encoding the non-muscle α-actinin isoform. Nevertheless, ActnΔ233 homozygous mutant flies were viable and fertile with no obvious defects. By comparing α-actinin protein distribution in wild type and ActnΔ233 mutant animals, it could be concluded that non-muscle α-actinin is the only isoform expressed in young embryos, in the embryonic central nervous system and in various actin-rich structures of the ovarian germline cells. In the ActnΔ233 mutant, α-actinin was detected not only in muscle tissue, but also in embryonic epidermal cells and in certain follicle cell populations in the ovaries. The population of α-actinin protein present in non-muscle cells of the ActnΔ233 mutant is referred to as FC-α-actinin (Follicle Cell). The follicular epithelium in the Drosophila ovary is a well characterised model system for studies on patterning and morphogenesis. Therefore, α-actinin expression, regulation and function in this tissue were further analysed. Examination of the α-actinin localisation pattern revealed that the basal actin fibres of the main body follicle cells underwent an organised remodelling during the final stages of oogenesis. This involved the assembly of a transient adhesion site in the posterior of the cell, in which α-actinin and Enabled (Ena) accumulated. Follicle cells genetically manipulated to lack all α-actinin isoforms failed to remodel their cytoskeleton and translocate Ena to the posterior of the cell, while the actin fibres as such were not affected. Neither was epithelial morphogenesis disrupted. The reorganisation of the basal actin cytoskeleton was also disturbed following ectopic expression of Decapentaplegic (Dpp) or as a result of a heat shock. At late oogenesis, the main body follicle cells express both non-muscle α-actinin and FC-α-actinin, while the dorsal anterior follicle cells express only non-muscle α-actinin. The dorsal anterior cells are patterned by the Dpp and Epidermal growth factor receptor (EGFR) signalling pathways, and they will ultimately secrete the dorsal appendages of the egg. Experiments involving ectopic activation of EGFR and Dpp signalling showed that FC-α-actinin is negatively regulated by combined EGFR and Dpp signalling. Ubiquitous overexpression of the adult muscle-specific α-actinin isoform induced the formation of aberrant actin bundles in migrating follicle cells that did not normally express FC-α-actinin, provided that the EGFR signalling pathway was activated in the cells. Taken together, this work contributes new data to our knowledge of α-actinin function and regulation in Drosophila. The cytoskeletal remodelling shown to depend on α-actinin function provides the first evidence that α-actinin has a role in the organisation of the cytoskeleton in a non-muscle tissue. Furthermore, the cytoskeletal remodelling constitutes a previously undescribed morphogenetic event, which may provide us with a model system for in vivo studies on adhesion dynamics in Drosophila.

Theoretical Studies on Coupled Electron and Proton Transfer in Cytochrome c Oxidase

The complexity of life is based on an effective energy transduction machinery, which has evolved during the last 3.5 billion years. In aerobic life, the utilization of the high oxidizing potential of molecular oxygen powers this machinery. Oxygen is safely reduced by a membrane bound enzyme, cytochrome c oxidase (CcO), to produce an electrochemical proton gradient over the mitochondrial or bacterial membrane. This gradient is used for energy-requiring reactions such as synthesis of ATP by F0F1-ATPase and active transport. In this thesis, the molecular mechanism by which CcO couples the oxygen reduction chemistry to proton-pumping has been studied by theoretical computer simulations. By building both classical and quantum mechanical model systems based on the X-ray structure of CcO from Bos taurus, the dynamics and energetics of the system were studied in different intermediate states of the enzyme. As a result of this work, a mechanism was suggested by which CcO can prevent protons from leaking backwards in proton-pumping. The use and activation of two proton conducting channels were also enlightened together with a mechanism by which CcO sorts the chemical protons from pumped protons. The latter problem is referred to as the gating mechanism of CcO, and has remained a challenge in the bioenergetics field for more than three decades. Furthermore, a new method for deriving charge parameters for classical simulations of complex metalloenzymes was developed.

Spatial ecology of a specialist insect herbivore : the leaf-mining moth Tischeria ekebladella on the pedunculate oak Quercus robur

Herbivorous insects comprise a major part of terrestrial biodiversity, and their interactions with their host plants and natural enemies are of vast ecological importance. A large body of research demonstrates that the ecology and evolution of these insects may be affected by trophic interactions, by abiotic influences, and by intraspecific processes, but so far research on these individual aspects has rarely been combined. This thesis uses the leaf-mining moth Tischeria ekebladella and the pedunculate oak (Quercus robur) as a case study to assess how spatial variation in trophic interactions and the physical distribution of host trees jointly affect the distribution, dynamics and evolution of a host-specific herbivore. With respect to habitat quality, Tischeria ekebladella experiences abundant variation at several spatial scales. Most of this variation occurs at small scales notably among leaves and shoots within individual trees. While hypothetically this could cause moths to evolve an ability to select leaves and shoots of high quality, I did not find any coupling between female preference and offspring performance. Based on my studies on temporal variation in resource quality I therefore propose that unpredictable temporal changes in the relative rankings of individual resource units may render it difficult for females to predict the fate of their developing offspring. With respect to intraspecific processes, my results suggest that limited moth dispersal in relation to the spatial distribution of oak trees plays a key role in determining the regional distribution of Tischeria ekebladella. The distribution of the moth is aggregated at the landscape level, where local leaf miner populations are less likely to be present where oaks are scarce. A modelling exercise based on empirical dispersal estimates revealed that the moth population on Wattkast an island in south-western Finland is spatially structured overall, but that the relative importance of local and regional processes on tree-specific moth dynamics varies drastically across the landscape. To conclude, my work in the oak-Tischeria ekebladella system demonstrates that the local abundance and regional distribution of a herbivore may be more strongly influenced by the spatial location of host trees than by their relative quality. Hence, it reveals the importance of considering spatial context in the study of herbivorous insects, and forms a bridge between the classical fields of plant-insect interactions and spatial ecology.

The influence of eutrophication on sexual selection in sticklebacks

Jordens ekologiska system undergår för tillfället stora förändringar pga. människans aktiviteter. Ett växande antal studier visar att dessa förändringar påverkar naturliga och sexuella urvalet och därmed evolutiva processer. Målet med detta arbete var att undersöka effekterna av omgivningsförändringar på sexuella urvalet genom att använda den ökade övergödningen inom storpiggen Gasterosteus aculeatus lekområden som modell system. Sexuella urvalet är en viktig evolutiv kraft med följder på populations- och artnivå (Kapitel 1). Avhandlingens olika delar fokuserar på övergödningens effekter på upptäckandet av partners, användningen av visuella- och doftsignaler i partnersval, och fördelningen av parningsframgången mellan bobyggande hanar. I Kapitel II och III simuleras hur grumlighet orsakad av fytoplankton påverkar hastigheten med vilken potentiella partners påträffas, genom effekter på synligheten. Resultaten visar att normala algblomningar i Östersjön har en måttlig effekt på finnandet av potentiella partners. Detta tyder på att algblomningarna troligen inte kommer att minska på selektiva parningen pga. ökade sökkostnader. I Kapitel IV visas att storspiggen ändrar relativa användningen av olika signaler när vattnets grumlighet ökar; visuella signaler minskar i betydelse medan doftsignaler ökar i betydelse. Samtidigt underlättas användandet av doftsignaler av ändringar i vattnets kemiska sammansättning då fotosyntesen intensifieras (Kapitel V). Lek i övergödda vatten kan ändå vara kostsamt både på individ- och populationsnivån, då parasiterade hanar, som troligen är dåligt genetiskt anpassade till sin miljö, lyckas få mer ägg i sina bon än friskare hanar som troligen är av högre genetisk kvalitet (Kapitel VI). Övergödningen påverkar således partnersval och konkurrensen om partners genom att påverka upptäckandet av potentiella partners, evalueringen av partners och fördelningen av partners inom lekområdena. De följder detta kan ha för evolutionen av sexuellt selekterad egenskaper och för populationers dynamik och livskraft är dock oklara. Avhandlingen visar på svårigheten att förutse följderna av omgivningsförändringar för sexuella urvalet och effekterna på individ och populationsnivå.