Reproductive Success Responses To Habitat Fragmentation In Eurasian Treecreepers

Siirretty Doriast

Myrkyllisten panssarisiimalevien tuottama bioluminesenssi Itämeressä : geeneistä malleihin

Phytoplankton constitute the basis of food webs and are responsible for almost all photosynthesis in the open sea. Occasionally, given suitable conditions, one phytoplankton species can increase in abundance and form a mass occurrence known as a bloom. Harmful Algal Blooms (HABs), in turn, can have adverse effects on the ecosystem, for example causing oxygen depletion, clogging of fish gills, or toxicity. HABs are common in shallow and stratified coastal waters and the number, frequency and coverage of areas affected by HABs are increasing globally mainly due to eutrophication, changes in nutrient ratios and global climate change. One of the main phytoplankton groups forming HABs are dinoflagellates. Among dinoflagellates the genus Alexandrium is particularly notorious with many species in this genus producing a variety of potent neurotoxins. Dinoflagellates are the only known photosynthetic organisms that can produce bioluminescence and the majority of bioluminescence in marine surface waters is produced by dinoflagellates. Bioluminescence in dinoflagellates is considered a defensive mechanism against grazing and many harmful dinoflagellate taxa produce bioluminescence. The dinoflagellate Alexandrium ostenfeldii forms dense bioluminescent blooms in shallow and sheltered areas of the Baltic Sea during the late summer. These blooms pose a potential threat to humans and ecosystems in the region due to observed production of toxins. The distribution and abundance of A. ostenfeldii is poorly known in the coastal waters of the Baltic Sea. The aim of this thesis was to study the variability of A. ostenfeldii bioluminescence production to evaluate whether bioluminescence can be used as an early warning signal of harmful dinoflagellate blooms in the Baltic Sea. More precisely, the aim was to study the expression of A. ostenfeldii bioluminescence to learn how much genetic, phenotypic and environmentally induced variability there is in bioluminescence production in the species. Studies conducted on luciferase genes and bioluminescence emission showed that bioluminescence is a prominent feature in Baltic A. ostenfeldii. Measurements on individual cell cultures and natural populations revealed large daily and seasonal variation in bioluminescence emission relating to the circadian rhythm in bioluminescence expression and seasonal changes in A. ostenfeldii abundance. Large intraspecific variation in bioluminescence production was observed in response to changes in temperature and salinity. A. ostenfeldii abundance, toxin concentrations and bioluminescence intensity were positively correlated in our field data. All tested A. ostenfeldii strains produced both bioluminescence and toxins and it can be assumed that concurrent production of both is a predominant property in Baltic A. ostenfeldii. The obtained results show that it is possible to relate bioluminescence to A. ostenfeldii bloom succession using automated measurements. However, the highly-localized distribution of blooms may require advance knowledge of potential bloom locations to be able to target the monitoring efforts. Species distribution modelling showed promise to address this problem by identifying potentially suitable habitats for A. ostenfeldii.Kasviplankton muodostaa ravintoketjun perustan ja on vastuussa lähes kaikesta perustuotannosta avoimilla merialueilla. Toisinaan suotuisissa olosuhteissa yksi kasviplanktonlaji saattaa runsastua huomattavasti ja muodostaa massaesiintymän eli kukinnan. Haitallisiksi leväkukinnoiksi kutsutaan sellaisia kukintoja, jotka aiheuttavat haittaa ympäristölle, muille vesieliöille tai ihmisille esimerkiksi vähentämällä hapen määrää vedessä, tukkimalla kalojen kiduksia tai erittämällä myrkkyjä. Haitallisia leväkukintoja esiintyy yleisesti matalissa ja suojaisissa rannikkovesissä ja niiden määrät ovat lisääntyneet maailmanlaajuisesti rehevöitymisen, ravinteiden suhteiden muuttumisen ja ilmastonmuutoksen seurauksena. Yksi tärkeimmistä haitallisia kukintoja muodostavista ryhmistä on panssarisiimalevät. Erityisesti monet Alexandrium-sukuun kuuluvat panssarisiimalevälajit tuottavat useita erilaisia hermomyrkkyjä. Monet panssarisiimalevälajit tuottavat lisäksi bioluminesenssia eli sinistä valoa, joka on parhaiten nähtävissä veden pinnalla yöaikaan. Ilmiö tunnetaan myös nimellä merituli. Alexandrium ostenfeldii –panssarisiimalevä muodostaa tiheitä valoa tuottavia kukintoja Itämeren rannikkoalueilla erityisesti loppukesästä. A. ostenfeldiin tuottamien myrkkyjen on osoitettu kertyvän simpukoihin ja kaloihin, ja lisäksi myrkyillä on haitallisia vaikutuksia kasvi- ja eläinplanktoniin. Lajin levinneisyys ja siihen vaikuttavat ympäristötekijät Itämeren rannikkoalueilla tunnetaan huonosti. Tämän väitöskirjan tavoitteena on tutkia kuinka paljon geneettistä, phenotyyppistä ja ympäristön aiheuttamaa vaihtelua A. ostenfeldii -lajin bioluminesenssin tuotannossa on ja voitaisiinko bioluminesenssin havainnointia käyttää ennakkovaroituksena myrkyllisestä panssarisiimaleväkukinnasta. Tulokset osoittavat, että kaikki Itämeren A. ostenfeldii -populaatiot tuottavat bioluminesenssia ja, että bioluminesenssin tuotossa on selvä vuorokausirytmi. Lisäksi tuotetun valon määrä vaihtelee populaation koon ja kehitysvaiheen mukaan. Lajin sisällä havaittiin suurta vaihtelua tuotetun bioluminesenssin määrässä suhteessa muutoksiin lämpötilassa ja suolapitoisuudessa. Luonnosta kerätyssä aineistossa havaittiin selvä positiivinen yhteys A. ostenfeldiin runsauden, tuotettujen myrkkyjen ja bioluminesenssin välillä. Kaikki testatut A. ostenfeldii - kannat tuottivat sekä bioluminesenssia että myrkkyjä, mikä viittaa siihen, että nämä kaksi ominaisuutta esiintyvät rinnakkain Itämeren populaatioissa. Saadut tulokset osoittavat, että on mahdollista yhdistää tuotetun valon määrä A. ostenfeldii -populaation kehittymiseen käyttäen automaattisia mittausmenetelmiä. Kukintojen hyvin paikallinen esiintyminen hankaloittaa kuitenkin niiden havaitsemista, minkä takia etukäteistieto mahdollisista kukintapaikoista olisi tärkeää. Habitaattimallien avulla voidaan kartoittaa ne alueet, jotka ovat erityisen alttiita A. ostenfeldii -kukinnoille. Lisäksi habitaattimalleja voidaan käyttää apuna ennustettaessa, miten etenevä ilmastonmuutos vaikuttaa A. ostenfeldii -kukintoihin Itämerellä

Observing the behaviour of amoxicillin in phosphate and ammonium buffers

In modern animal husbandry veterinary medicines are used non therapeutically to promote the health and growth of animals. While economical losses due to animal sickness have been reduced this practice has also created problems. As it is generally known many pharmaceuticals have antibiotic properties and low biodegradability. Nowadays their behaviour in the environment is a common topic of discussion and research. In this study, amoxicillin was added into phosphate and ammonium buffer solutions. The purpose was to observe how the pharmaceutical is behaving in the presence of PO43- and NH4+ ions during time span of approximately 180min. 2% MeOH solutions was used as control. Measurements were done with HPLC. Phenomenex Gemini-NX 5µm C18 110A column was used. Mobile phase was 10mM pH 6,1 KH2PO4 and MeCN (95:5). Wavelength was set to 227nm and flow rate to 1,5ml/min. The chromatograms displayed two analyte peaks for each sample. Since no MS was performed, AMX could not be identified. During method development phase peak 2 displayed signs of molecular changes. However, these were not observed in the final results, suggesting that no degradation had occurred during the experiment.Nykyaikaisessa maataloudessa tuotantoeläimiä lääkitään ennaltaehkäisevästi tuottavuuden parantamiseksi. Vaikka eläimien sairastumisesta johtuva hävikki on vähentynyt, käytäntö voi aiheuttaa myös ongelmia. Kuten on yleisesti tiedossa, monet lääkeaineet ovat antibakteerisia ja hajoavat siksi hitaammin luonnossa. Aihe on saanut viime vuosina huomiota niin tutkimuksessa kuin mediassakin. Tässä tutkimuksessa pyrittiin selvittämään onko fosfaatti- ja ammoniumionien pitoisuuksilla vaikutusta amoksisilliinin käyttäytymiseen liuoksessa. Työssä lääkeainetta lisättiin puskuriliuoksiin, joista sen pitoisuus määritettiin tietyin väliajoin HPLC-laitteella n. 180min ajan. Kontrollinäytteenä käytettiin 2% MeOH liuosta. Käytettävä kolonni oli Phenomenex Gemini-NX 5µm C18 110A. Eluenttina käytettiin isokraattista 10mM pH 6,1 KH2PO4 ja MeCN (95:5). UV-lampun aallonpituus säädettiin 227nm ja järjestelmän virtausnopeus 1,5ml/min. Lopullisissa mittaustuloksissa esiintyi mahdollisesti kaksi eri ainetta. Näitä ei voitu tunnistaa, sillä työssä ei käytetty MS-laitetta. Menetelmää kehittäessä toinen aineista näytti hajoavan, mutta vastaavia havaintoja ei kuitenkaan tehty varsinaisissa mittauksissa. Vaikka tunnistamattomat aineet eivät pysyneet kokeen aikana täysin muuttumattomina, tulokset eivät todistettavasti viitanneet lääkeaineen suoranaiseen hajoamiseen

Antiviral Inhibition of Enveloped Virus Release by Tetherin/BST-2: Action and Counteraction

Tetherin (BST2/CD317) has been recently recognized as a potent interferon-induced antiviral molecule that inhibits the release of diverse mammalian enveloped virus particles from infected cells. By targeting an immutable structure common to all these viruses, the virion membrane, evasion of this antiviral mechanism has necessitated the development of specific countermeasures that directly inhibit tetherin activity. Here we review our current understanding of the molecular basis of tetherin’s mode of action, the viral countermeasures that antagonize it, and how virus/tetherin interactions may affect viral transmission and pathogenicity

Diversity of luciferase sequences and bioluminescence production in Baltic Sea Alexandrium ostenfeldii

The toxic dinoflagellate Alexandrium ostenfeldii is the only bioluminescent bloom-forming phytoplankton in coastal waters of the Baltic Sea. We analysed partial luciferase gene (lcf) sequences and bioluminescence production in Baltic A. ostenfeldii bloom populations to assess the distribution and consistency of the trait in the Baltic Sea, and to evaluate applications for early detection of toxic blooms. Lcf was consistently present in 61 Baltic Sea A. ostenfeldii strains isolated from six separate bloom sites. All Baltic Sea strains except one produced bioluminescence. In contrast, the presence of lcf and the ability to produce bioluminescence did vary among strains from other parts of Europe. In phylogenetic analyses, lcf sequences of Baltic Sea strains clustered separately from North Sea strains, but variation between Baltic Sea strains was not sufficient to distinguish between bloom populations. Clustering of the lcf marker was similar to internal transcribed spacer (ITS) sequences with differences being minor and limited to the lowest hierarchical clusters, indicating a similar rate of evolution of the two genes. In relation to monitoring, the consistent presence of lcf and close coupling of lcf with bioluminescence suggests that bioluminescence can be used to reliably monitor toxic bloom-forming A. ostenfeldii in the Baltic Sea.Peer reviewe

Impact of short term HAART initiated during the acute or chronic stage on SIV infection of the male genital tract

International audiencen.

Human prostate supports more efficient replication of HIV-1 R5 than X4 strains ex vivo

<p>Abstract</p> <p>Background</p> <p>In order to determine whether human prostate can be productively infected by HIV-1 strains with different tropism, and thus represent a potential source of HIV in semen, an organotypic culture of prostate from men undergoing prostatic adenomectomy for benign prostate hypertrophy (BPH) was developed. The presence of potential HIV target cells in prostate tissues was investigated using immunohistochemistry. The infection of prostate explants following exposures with HIV-1 R5, R5X4 and X4 strains was analyzed through the measure of RT activity in culture supernatants, the quantification of HIV DNA in the explants and the detection of HIV RNA+ cells <it>in situ</it>.</p> <p>Results</p> <p>The overall prostate characteristics were retained for 2^1/2weeks in culture. Numerous potential HIV-1 target cells were detected in the prostate stroma. Whilst HIV-1 R5_SF162strain consistently productively infected prostatic T lymphocytes and macrophages, the prototypic X4_IIIBstrain and a primary R5X4 strain showed less efficient replication in this organ.</p> <p>Conclusion</p> <p>The BPH prostate is a site of HIV-1 R5 replication that could contribute virus to semen. A limited spreading of HIV-1 X4 and R5X4 in this organ could participate to the preferential sexual transmission of HIV-1 R5 strains.</p

Impact of Short-Term HAART Initiated during the Chronic Stage or Shortly Post-Exposure on SIV Infection of Male Genital Organs

International audienceBACKGROUND: The male genital tract is suspected to constitute a viral sanctuary as persistent HIV shedding is found in the semen of a subset of HIV-infected men receiving effective antiretroviral therapy (HAART). The origin of this persistent shedding is currently unknown. Phylogenetic studies indicated that HIV in semen from untreated men arises from local sources and/or passive diffusion from the blood. We previously demonstrated in human and macaque low levels and localized infection of several semen-producing organs by HIV/SIV. Using a macaque model, this study investigates the impact of short term HAART (2-4 weeks) initiated either during the asymptomatic chronic stage or 4 h post-intravenous inoculation of SIVmac251 on the infection of male genital organs. METHODOLOGY/PRINCIPAL FINDINGS: Short term HAART during the chronic stage decreased blood viral load. No major impact of HAART was observed on SIV DNA levels in male genital organs using a sensitive nested PCR assay. Using in situ hybridization, SIV RNA+ cells were detected in all male genital tract organs from untreated and treated animals with undetectable blood viral load following HAART. Infected CD68+ myeloid cells and CD3+ T lymphocytes were detected pre- and post-HAART. In contrast, short term HAART initiated 4 h post-SIV exposure led to a drastic decrease of the male genital tissues infection, although it failed to prevent systemic infection. In both cases, HAART tended to decrease the number of CD3+ T cells in the male organs. CONCLUSIONS: Our results indicate that the established infection of male genital organs is not greatly impacted by short term HAART, whereas the same treatment during pre-acute phase of the infection efficiently impairs viral dissemination to the male genital tract. Further investigations are now needed to determine whether infection of male genital organs is responsible for long term persistent HIV shedding in semen despite HAART

Using change trajectories to study the impacts of multi-annual habitat loss on fledgling production in an old forest specialist bird

The loss and subdivision of habitat into smaller and more spatially isolated units due to human actions has been shown to adversely affect species worldwide. We examined how changes in old forest cover during eight years were associated with the cumulative number of fledged offspring at the end of study period in Eurasian treecreepers (Certhia familiaris) in Central Finland. We were specifically interested in whether the initial level of old forest cover moderated this relation. We applied a flexible and powerful approach, latent growth curve modelling in a structural equation modeling (SEM) framework, to create trajectories describing changes in old forest cover through time, and studied how this change at both the territory core and landscape scales impacted fledging numbers. Our main finding was that at the territory core scale the negative impact of habitat loss on fledging numbers was lessened by the higher levels of initial forest cover, while no association was found at the landscape scale. Our study highlights a powerful, but currently under-utilised methodology among ecologists that can provide important information about biological responses to changes in the environment, providing a mechanistic way to study how land cover dynamics can affect species responses

Antiviral responses of human Leydig cells to mumps virus infection or poly I:C stimulation

International audienceBACKGROUND: The immuno-privileged status of the testis is essential to the maintenance of its functions, and innate immunity is likely to play a key role in limiting harmful viral infections, as demonstrated in the rat. In men mumps virus infects Leydig cells and has deleterious effects on testosterone production and spermatogenesis. The aim of this study was to test whether mumps virus infection of isolated human Leydig cells was associated with an inhibition of their innate antiviral defences. METHODS: Leydig cell production of mRNA and protein for interferons (IFNs) and of three antiviral proteins-2'5' oligoadenylate synthetase (2'5'OAS), double-stranded RNA-activated protein kinase (PKR) and MxA-was investigated, in the absence or presence of mumps virus or viral stimuli including poly I:C, a mimetic of RNA viruses replication product. RESULTS: Stimulated or not, human Leydig cells appeared unable to produce routinely detectable IFNs alpha, beta and gamma. Although the level of PKR remained unchanged after stimulation, the expression of 2'5'OAS and MxA was enhanced following either mumps virus or poly I:C exposure (P < 0.05 versus control). CONCLUSIONS: Overall, our results demonstrate that mumps virus replication in human Leydig cells is not associated with a specific inhibition of IFNs or 2'5'OAS, MxA and PKR production and that these cells display relatively weak endogenous antiviral abilities, as opposed to their rat counterparts