Redox dysregulation in schizophrenia : effect on myelination of cortical structures and connectivity

Cette thèse traite du rôle qu'un facteur de risque génétique développé chez les patients souffrant de schizophrénie, à savoir un déficit de la synthèse du glutathion, peut jouer dans les anomalies de la connectivité cérébrale trouvées chez ces patients. L'essentiel du travail a été consacré à évaluer la structure de la substance blanche dans l'ensemble du cerveau chez un modèle animal par une méthode similaire à celle utilisée en recherche clinique avec l'imagerie par résonance magnétique (IRM). Cette approche de translation inverse chez la souris knock-out de glutamate-cystéine ligase modulateur sous-unité (Gclm KO), avait l'objectif d'étudier l'effet des défenses redox déficientes sur le développement des connexions cérébrales, tout en excluant celui des facteurs non liés au génotype. Après avoir établi le protocole de recherche, l'influence d'une manipulation environnementale a également été étudiée. Pour effectuer une analyse statistique fiable des données d'IRM obtenues, nous .avons d'abord créé un atlas du cerveau de la souris afin de l'utiliser comme modèle pour une segmentation précise des différentes régions du cerveau sur les images IRM obtenues in vivo. Les données provenant de chaque région d'intérêt ont ensuite été étudiées séparément. La qualité de cette méthode a été évaluée dans une expérience de simulation pour déduire la puissance statistique réalisable dans chaque région en fonction du nombre d'animaux utilisés. Ces outils d'analyse nous ont permis d'évaluer l'intégrité de la substance blanche dans le cerveau des souris durant le développement grâce à une expérience longitudinale, en utilisant l'imagerie du tenseur de diffusion (DTI). Nous avons ainsi observé des anomalies dans les paramètres dérivés du tenseur (diffusivité et anisotropie) dans la Commissure Antérieure et le Fimbria/Fornix des souris Gclm KO, par rapport aux animaux contrôles. Ces résultats suggèrent une substance blanche endommagée dans ces régions. Dans une expérience électrophysiologique, Pascal Steullet a montré que ces anomalies ont des conséquences fonctionnelles caractérisées par une réduction de la vitesse de conduction dans les fibres nerveuses. Ces données renforcent les conclusions des analyses d'imagerie. Le mécanisme par lequel une dérégulation redox affecte la structure de la substance blanche reste encore à définir, car une analyse immunohistochimique des protéines constituantes de la couche de myéline des fibres concernées n'a pas donné de résultats concluants. Nous avons également constaté un élargissement des ventricules dans les jeunes souris Gclm KO, mais pas chez les adultes et des anomalies neurochimiques déjà connues chez ces animaux (Duarte et al. 2011), à savoir une réduction du Glutathion et une augmentation de l'acide N-acétylaspartique, de l'Alanine et du ratio Glutamine/Glutamate. Nous avons ensuite testé l'effet d'un stress environnemental supplémentaire, l'élevage en isolement social, sur le phénotype. Ce stress n'a eu aucun effet sur la structure de la substance blanche évaluée par DTI, mais a réduit la concentration de myo-Inositol et augmenté le ratio de Glutamine/Glutamate dans le cortex frontal. Nous avons aussi reproduit dans ce groupe indépendant d'animaux les effets du génotype sur le profil neurochimique, sur la taille des ventricules et aussi sur les paramètres dérivés du tenseur de diffusion dans le Fimbria/Fornix, mais pas dans la Commissure Antérieure. Nos résultats montrent qu'une dérégulation redox d'origine génétique perturbe la structure et la fonction de la substance blanche dans des régions spécifiques, causant ainsi l'élargissement des ventricules. Ces phénotypes rassemblent certaines caractéristiques neuro-anatomiques de la schizophrénie, mais les mécanismes qui en sont responsables demeurent encore inconnus. L'isolement social n'a pas d'effet sur la structure de la substance blanche évaluée par DTI, alors qu'il est prouvé qu'il affecte la maturation des oligodendrocytes. La neurochimie corticale et en particulier le rapport Glutamine/Glutamate a été affecté par le dérèglement redox ainsi que par l'isolement social. En conséquence, ce ratio représente un indice prometteur dans la recherche sur l'interaction du stress environnemental avec le déséquilibre redox dans le domaine de la schizophrénie. -- The present doctoral thesis is concerned with the role that a genetic risk factor for the development of schizophrenia, namely a deficit in Glutathione synthesis, may play in the anomalies of brain connectivity found in patients. Most of the effort was devoted to perform a whole-brain assessment of white matter structure in the Glutamate-Cysteine ligase modulatory knockout mouse model (Gclm KO) using Magnetic Resonance Imaging (MRI) techniques similar to those used in state-of-the-art clinical research. Such reverse translational approach taking brain imaging from the bedside to the bench aimed to investigate the role that deficient redox defenses may play in the development of brain connections while excluding all influencing factors beside the genotype. After establishing the protocol, the influence of further environmental manipulations was also studied. Analysis of MRI images acquired in vivo was one of the main challenges of the project. Our strategy consisted in creating an atlas of the mouse brain to use as segmentation guide and then analyze the data from each region of interest separately. The quality of the method was assessed in a simulation experiment by calculating the statistical power achievable in each brain region at different sample sizes. This analysis tool enabled us to assess white matter integrity in the mouse brain along development in a longitudinal experiment using Diffusion Tensor Imaging (DTI). We discovered anomalies in diffusivity parameters derived from the tensor in the Anterior Commissure and Fimbria/Fornix of Gclm KO mice when compared to wild-type animals, which suggest that the structure of these tracts is compromised in the KO mice. In an elegant electrophysiological experiment, Pascal Steullet has provided evidence that these anomalies have functional consequences in form of reduced conduction velocity in the concerned tracts, thus supporting the DTI findings. The mechanism by which redox dysregulation affects WM structure remains unknown, for the immunohistochemical analysis of myelin constituent proteins in the concerned tracts produced inconclusive results. Our experiments also detected an enlargement of the lateral ventricles in young but not adult Gclm KO mice and confirmed neurochemical anomalies already known to affect this animals (Duarte et al. 2011), namely a reduction in Glutathione and an increase in Glutamine/Glutamate ratio, N-acetylaspartate and Alanine. Using the same methods, we tested the effect of an additional environmental stress on the observed phenotype: rearing in social isolation had no effect on white matter structure as assessed by DTI, but it reduced the concentration of myo-Inositol and increased the Glutamine/Glutamate ratio in the frontal cortex. We could also replicate in this separate group of animals the effects of genotype on the frontal neurochemical profile, ventricular size and diffusivity parameters in the Fimbria/Fornix but not in the Anterior Commissure. Our data show that a redox dysregulation of genetic origin may disrupt white matter structure and function in specific tracts and cause a ventricular enlargement, phenotypes that resemble some neuroanatomical features of schizophrenia. The mechanism responsible remains however unknown. We have also demonstrated that environmental stress in form of social isolation does not affect white matter structure as assessed by DTI even though it is known to affect oligodendrocyte maturation. Cortical neurochemistry, and specifically the Glutamine to Glutamate balance was affected both by redox dysregulation and social isolation, and is thus a good target for further research on the interaction of redox imbalance and environmental stress in schizophrenia.

High expression levels of macrophage migration inhibitory factor sustain the innate immune responses of neonates.

The vulnerability to infection of newborns is associated with a limited ability to mount efficient immune responses. High concentrations of adenosine and prostaglandins in the fetal and neonatal circulation hamper the antimicrobial responses of newborn immune cells. However, the existence of mechanisms counterbalancing neonatal immunosuppression has not been investigated. Remarkably, circulating levels of macrophage migration inhibitory factor (MIF), a proinflammatory immunoregulatory cytokine expressed constitutively, were 10-fold higher in newborns than in children and adults. Newborn monocytes expressed high levels of MIF and released MIF upon stimulation with Escherichia coli and group B Streptococcus, the leading pathogens of early-onset neonatal sepsis. Inhibition of MIF activity or MIF expression reduced microbial product-induced phosphorylation of p38 and ERK1/2 mitogen-activated protein kinases and secretion of cytokines. Recombinant MIF used at newborn, but not adult, concentrations counterregulated adenosine and prostaglandin E2-mediated inhibition of ERK1/2 activation and TNF production in newborn monocytes exposed to E. coli. In agreement with the concept that once infection is established high levels of MIF are detrimental to the host, treatment with a small molecule inhibitor of MIF reduced systemic inflammatory response, bacterial proliferation, and mortality of septic newborn mice. Altogether, these data provide a mechanistic explanation for how newborns may cope with an immunosuppressive environment to maintain a certain threshold of innate defenses. However, the same defense mechanisms may be at the expense of the host in conditions of severe infection, suggesting that MIF could represent a potential attractive target for immune-modulating adjunctive therapies for neonatal sepsis.

Neuronal activity controls the antagonistic between PGC-1α and SMRT in regulating antioxidant defences

Transcriptional coactivators and corepressors often have multiple targets and can have opposing actions on transcription and downstream physiological events. The coactivator peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is under-expressed in Huntington's disease and is a regulator of antioxidant defenses and mitochondrial biogenesis. We show that in primary cortical neurons, expression of PGC-1α strongly promotes resistance to excitotoxic and oxidative stress in a cell autonomous manner, whereas knockdown increases sensitivity. In contrast, the transcriptional corepressor silencing mediator of retinoic acid and thyroid hormone receptors (SMRT) specifically antagonizes PGC-1α-mediated antioxidant effects. The antagonistic balance between PGC-1α and SMRT is upset in favor of PGC-1α by synaptic activity. Synaptic activity triggers nuclear export of SMRT reliant on multiple regions of the protein. Concommitantly, synaptic activity post-translationally enhances the transactivating potential of PGC-1α in a p38-dependent manner, as well as upregulating cyclic-AMP response element binding protein-dependent PGC-1α transcription. Activity-dependent targeting of PGC-1α results in enhanced gene expression mediated by the thyroid hormone receptor, a prototypical transcription factor coactivated by PGC-1α and repressed by SMRT. As a consequence of these events, SMRT is unable to antagonize PGC-1α-mediated resistance to oxidative stress in synaptically active neurons. Thus, PGC-1α and SMRT are antagonistic regulators of neuronal vulnerability to oxidative stress. Further, this coactivatorcorepressor antagonism is regulated by the activity status of the cell, with implications for neuronal viability.

Os DNA sintéticos anti-sentido

One old dream of the chemist in the field of the drug research is to create molecules capable of reaching their target with the precision of a missile. To accomplish it these molecules must have the propriety of distinguishing qualitative differences between healthy and diseased cells. A therapy based on this principle, able of eradicating specifically defective cells, or cells affected by a pathogen has an enormous advantage with the regard to the classical approach in which the cytotoxic drugs merely exploit quantitative biochemical and kinetic differences between abnormal and normal cells. We present in this article a review on the chemical synthesis of analogues of desoxyribonucleotides and on results obtained on the specific and irreversible inhibition of undesired genetic expression using the antisense principle.

Experimental assessment of the effects of a Neotropical nocturnal piscivore on juvenile native and invasive fishes

We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus) and two native (yellowtail tetra Astyanax altiparanae and streaked prochilod Prochilodus lineatus) fish species were offered as prey to P. corruscans in 300 L aquaria with three habitat complexity treatments (0%, 50% and 100% structure-covered). Prey survival was variable through time and among species (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus), depending largely on species-specific prey behavior but also on prey size and morphological defenses. Habitat complexity did not directly affect P. corruscans piscivory but some prey species changed their microhabitat use and shoaling behavior among habitat treatments in predator’s presence. Pseudoplatystoma corruscans preyed preferentially on smaller individuals of those invasive species with weak morphological defensive features that persisted in a non-shoaling behavior. Overall, our results contrast with those in a companion experiment using a diurnal predator, suggesting that nocturnal piscivores preferentially prey on different (rather diurnal) fish species and are less affected by habitat complexity. Our findings suggest that recovering the native populations of P. corruscans might help controling some fish species introduced to the Paraná River basin, particularly C. piquiti and O. niloticus, whose parental care is expected to be weak or null at night

Decrease in the diversity of pyrrolizidine alkaloids of Senecio pterophorus after invasion

Pyrrolizidine alkaloids (PAs) are N-based plant secondary metabolites that function as chemical defenses against vertebrate and invertebrate herbivores. PAs can be highly variable at intraspecific level, both in their absolute and relative concentrations. Changes in the chemical composition of exotic plants when they invade a new environment have been poorly explored. Here we studied the biogeographical variation on PAs in Senecio pterophorus (Asteraceae) in the native region in Eastern South Africa, an expanded region in Western South Africa, and two introduced regions in Australia and Europe. PAs in S. pterophorus were represented by the highly toxic 1,2-unsaturated PAs and the less toxic 1,2-saturated PAs. Our results show a change in the plant chemical composition after invasion. Total PAs concentrations were highest in Australia compared to any other region. Plants from Europe contained the highest relative concentrations of 1,2-saturated PAs. The positive correlation between the chemical and the genetic distances estimated between populations suggests that the chemical profiles in the non-native regions were related to the plant dispersal routes. The decrease in the chemical diversity and the change in the absolute PAs concentrations in S. pterophorus after invasion may have consequences in the interactions between plants and herbivores in the novel habitats.

Química forense: perspectivas sobre novos métodos analíticos aplicados à documentoscopia, balística e drogas de abuso

In this review recent methods developed and applied to solve criminal occurences related to documentoscopy, ballistic and drugs of abuse are discussed. In documentoscopy, aging of ink writings, the sequence of line crossings and counterfeiting of documents are aspects to be solved with reproducible, fast and non-destructive methods. In ballistic, the industries are currently producing ''lead-free'' or ''nontoxic'' handgun ammunitions, so new methods of gunshot residues characterization are being presented. For drugs analysis, easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is shown to provide a relatively simple and selective screening tool to distinguish m-CPP and amphetamines (MDMA) tablets, cocaine and LSD.

Compostos orgânicos voláteis na defesa induzida das plantas contra insetos herbívoros

The identification and manipulation of chemical compounds involved in vital activities of arthropods have the potential for developing less aggressive pest control strategies. Herbivory induces the emission of volatile organic compounds involved in the recruitment of natural enemies, plant-plant interactions and repellency of other herbivores. In this report, we review the main chemical groups of volatile organic compounds and their ecological functions, provide an overview of the signal transduction pathways activated upon herbivory, and review the current state of knowledge for practical applications in pest management. We conclude by proposing perspectives for future research.

Noctuidae-induced plant volatiles: current situation and prospects

Noctuids are phytophagous lepidopterans with some species causing significant damage to agriculture. The host plants, in turn, have developed defense mechanisms to cope with them, for instance chemical defenses. In this study we review the literature on plant volatiles induced by noctuids, and discuss the methodologies used to induce the production of volatiles that are usually employed in plant defense mechanisms. Future prospects involving this line of research in pest control are also discussed.

Current-phase relation in graphene Josephson junction

In this thesis, we present the results of high-frequency measurements on superconductor-graphene-superconductor junctions. We obtained the relation between the supercurrent through the junction and the superconducting phase. The relation allowed us to extract true critical current and to determine the transport regime of graphene in our SGS-junction samples at the Dirac point and away from it. An experimental temperature dependence of the current-phase relation is presented. We have calculated theoretical supercurrent-phase relation in the case of ballistic and diffusive junction. For the diffusive case, we have considered short and long limits where the coherence length is larger or smaller than the sample length, respectively.

Ballistisen simuloinnin liikeidean kehittämismahdollisuudet

Asevaikutusta laukaisusta kohteeseen simuloiva integroitu laskentaketju koostuu sisä-, ulko- ja maaliballistiikan malleista. Ulkoballistiikka kattaa laskentamallit radanlaskennan, sääkorjauksen ja ammusaerodynamiikan alueilla. Graafisella käyttöliittymällä toteutetulla, fysikaalisesti tarkkaan mallinnukseen perustuvalla ja kokonaisuuden kattavalla laskentajärjestelmällä on kasvavaa tarvetta teknisiä ja koulutuksellisia tarkoituksia varten. Erikoisesti, jos laskentaketjuun lisätään räjähdysvaikutuksen mallintaminen, voidaan simuloida asejärjestelmien vaikutusta kohteessa käyttäjien arvostamalla tavalla. Tietointensiiviset ballistiikan laskentamallit ovat välttämättömiä työkaluja teknisen suunnitteluosaamisen kattamiseksi ja kilpailuedun luomiseksi verkostoituneessa yritysympäristössä. Yliopistotutkimuksen tuottamien laskennallisten menetelmien hyötykäyttö yritysten suunnittelujärjestelmissä syventää teknistä osaamista, jolla on myös henkilöstöä motivoiva vaikutus teknisesti vaikeutuvilla markkinoilla. Työssä arvioidaan toimialaa analysoimalla eri käyttötarpeita samoille tietokantoihin tukeutuville laskentamalleille. Tarkastellaan teknisiä perusteita, käyttöympäristöjä ja markkinoita liiketoimintamahdollisuuksien tunnistamiseksi. Työn tuloksena syvennetään näkemystä ydinosaamisista ja visioidaan liikeidean erottumista kilpailijoista, markkinoita ja sen kehittämistä.

Secondary seed dispersal of Ricinus communis Linnaeus (Euphorbiaceae) by ants in secondary growth vegetation in Minas Gerais

In this study, I tested the efficacy of ants as secondary seed dispersers of Ricinus communis in southeastern Brazil. In a natural population of 143 individuals, I determined the ballistic dispersal distance for 62 seeds and 100 additional seeds were experimentally offered to ants in groups of ten seeds along a transect of 50 m. Fifty-three seeds were removed by ants, mainly by the leafcutter Atta sexdens (90.4%). The dispersal distance by ants was high, compared to the global average (4.38 m ± 0.74 m vs. 0.96 m), but was lower than the ballistic distance (7.27 m ± 0.13 m). Ants increased the total dispersal distance (8.66 m ± 0.60 m), but the main benefit for the plant was the directed dispersal, with seed deposition on the enriched soil of ant nests.

Detection of virulence-associated genes in Salmonella Enteritidis isolates from chicken in South of Brazil

Salmonella spp. are considered the main agents of foodborne disease and Salmonella Enteritidis is one of the most frequently isolated serovars worldwide. The virulence of Salmonella spp. and their interaction with the host are complex processes involving virulence factors to overcome host defenses. The purpose of this study was to detect virulence genes in S. Enteritidis isolates from poultry in the South of Brazil. PCR-based assays were developed in order to detect nine genes (lpfA, agfA, sefA, invA, hilA, avrA, sopE, sivH and spvC) associated with the virulence in eighty-four isolates of S. Enteritidis isolated from poultry. The invA, hilA, sivH, sefA and avrA genes were present in 100% of the isolates; lpfA and sopE were present in 99%; agfA was present in 96%; and the spvC gene was present in 92%. It was possible to characterize the isolates with four different genetic profiles (P1, P2, P3 and P4), as it follows: P1, positive for all genes; P2, negative only for spvC; P3, negative for agfA; and P4, negative for lpfA, spvC and sopE. The most prevalent profile was P1, which was present in 88% of the isolates. Although all isolates belong to the same serovar, it was possible to observe variations in the presence of these virulence-associated genes between different isolates. The characterization of the mechanisms of virulence circulating in the population of Salmonella Enteritidis is important for a better understanding of its biology and pathogenicity. The frequency of these genes and the establishment of genetic profiles can be used to determine patterns of virulence. These patterns, associated with in vivo studies, may help develop tools to predict the ability of virulence of different strains.

Ilmavoimat ulko- ja turvallisuuspolitiikan välineenä Suomessa vuonna 2025

Suomen puolustuspolitiikka nojaa tulevaisuudessa yhä enemmän kansainväliseen yhteistyöhön ja verkottuneen puolustuksen periaatteisiin. Puolustusmateriaalikustannusten kasvaminen ohjaa kumppaneita hakemaan uusia yhteistoimintatapoja ns. Pooling & Sharing ja Smart Defense-periaatteiden mukaisesti. Viimeisen vuosikymmenen aikana Suomen asema turvallisuuspoliittisessa kontekstissa on merkittävästi muuttunut eurooppalaisen, pohjoismaisen sekä Suomen ja Yhdysvaltojen tiivistyneen yhteistyön seurauksena. Suomen saavuttama asema Naton rauhankumppanina, pohjoismainen NORDEFCO-sotilasyhteistyö sekä kumppanuus Yhdysvaltojen kanssa muodostavat merkittävän ulkopoliittisen viestin geopoliittiseen ympäristöömme. Eräs Suomen ulkopolitiikan tärkeimmistä tavoitteista on sotilaallisen hyökkäyksen kohteeksi joutumisen välttäminen. Päämäärä pyritään saavuttamaan ulkopolitiikan ja diplomatian keinoin sekä ylläpitämällä uskottavaa kansallista puolustuskykyä. Keskeinen tekijä Suomen puolustuksen uskottavuudelle on kansainvälinen sotilasyhteistyö ja asevoimien järjestelmien sekä käyttö- ja toimintaperiaatteiden yhteentoimivuus. Puolustusvoimille hankittava pitkän kantaman ilmasta maahan –kyky, JASSM-ohjus (Joint Air-to-Surface Standoff Missile), mahdollistaa tulevaisuudessa operaatioiden ulottamisen vastustajan syvyyteen. Tällä suorituskyvyllä voi olla ennaltaehkäisevä vaikutus Suomen joutumiseksi sotilaallisen hyökkäyksen kohteeksi tai Suomen alueen hyväksi käyttämiseksi sotilaallisen uhkan kohdistuessa lähialueen Nato jäsenmaihin. Arvioitaessa Suomen puolustuksen uskottavuutta tarkastellaan useimmiten Venäjän sotilaspoliittista ja materiaalista kehitystä Suomen lähialueella. Tarkastelu rajoittuu usein geopoliittisesti Itämeren ympäristöön, jolloin globaalit muutostekijät tai Suomen muuttunut asema kansainvälisessä järjestelmässä jäävät huomioimatta. Asevoimien käyttäminen valtion ulkopoliittisten päämäärien tukemiseksi on kuulunut erityisesti suurvaltojen politiikkaan. Ranskassa la diplomatie aérienne ja Yhdysvalloissa Air Diplomacy käsittävät yleiseen diplomatiaan perustuvia toiminnan osa-alueita, joilla ilmavoimat voivat joko yhteistyön tai sotilaallisen pelotteen keinoin vaikuttaa valtioidensa ulkopolitiikkaan tai kansallisiin intresseihin. Tämän tutkimuksen pääongelmaksi muodostui kysymys, miten Suomen ilmavoimat voisi tukea ulkopoliittisten päämäärien saavuttamista Suomessa vuonna 2025. Ongelman ratkaisemiseksi selvitettiin, millainen on mahdollinen Suomen turvallisuuspoliittinen toimintaympäristö vuonna 2025 ja mitä tarkoittavat käsitteet la diplomatie aérienne ja Air Diplomacy. Tutkimus toteutettiin tulevaisuuden tutkimuksen menetelmin luomalla tutkittavasta ilmiöstä systeeminen malli (systeemiajattelu) sekä toteuttamalla 18 asiantuntijan argumentoiva Delfoi-paneeli. Systeemissä huomioitiin Suomen geopoliittiseen ympäristöön vaikuttavia muutostekijöitä. Tutkimus osoitti, että suomalainen sotilasstrategia sekä ulkopolitiikan ja puolustusvoimien välinen suhde toisiinsa ovat osittain jäsentymättä. Puolustusvoimien tehtävät eivät nykyisessä muodossaan tue kenttäohjesäännössä määriteltyjen Suomen puolustuksen ulottuvuuksien mukaisia ulkopoliittisia päämääriä. Puolustusvoimien tehtäviin eivät sisälly Islannin ilmavalvonnan tyyppiset, ulkopoliittisia päämääriä tavoittelevat tehtävät. Asevoimadiplomatian keinoin on mahdollista nostaa Suomen painoarvoa kansainvälisessä järjestelmässä ja vahvistaa uskottavaa puolustuskykyä suhteessa muihin valtioihin. Geopoliittisessa ympäristössämme asevoimadiplomatia voi lisätä lähialueen vakautta ja korottaa mahdollisen vastustajan kynnystä kohdistaa Suomeen sotilaallisia operaatioita jopa ilman sotilaallista liittoutumista. Ilmavoimadiplomatia-käsitteelle ei toistaiseksi koettu tarvetta. Tutkimus osoitti, että Suomen ilmavoimien korkea yhteensopivuus, tiivis kansainvälinen yhteistyö sekä monipuolinen keinovalikoima mahdollistavat tulevaisuudessa valtion ulkopoliittisten päämäärien tukemisen. Tärkeimpiä ilmavoimadiplomatian keinoja vuonna 2025 ovat osallistuminen sotilaalliseen kriisinhallintaan, kansainvälinen harjoitusyhteistyö, ilmavoimien korkean valmiuden ja suorituskyvyn osoittaminen ulkovalloille sekä sotilaallinen tiedonvaihto. 2020-luvulla ulkopoliittisesti merkittävä ratkaisu on päätös Hornetin seuraajan hankinnasta.

Functional Genomic Approaches for Deciphering Plant-Virus Interactions

Plant-virus interactions are very complex in nature and lead to disease and symptom formation by causing various physiological, metabolic and developmental changes in the host plants. These interactions are mainly the outcomes of viral hijacking of host components to complete their infection cycles and of host defensive responses to restrict the viral infections. Viral genomes contain only a small number of genes often encoding for multifunctional proteins, and all are essential in establishing a viral infection. Thus, it is important to understand the specific roles of individual viral genes and their contribution to the viral life cycles. Among the most important viral proteins are the suppressors of RNA silencing (VSRs). These proteins function to suppress host defenses mediated by RNA silencing and can also serve in other functions, e.g. in viral movement, transactivation of host genes, virus replication and protein processing. Thus these proteins are likely to have a significant impact on host physiology and metabolism. In the present study, I have examined the plant-virus interactions and the effects of three different VSRs on host physiology and gene expression levels by microarray analysis of transgenic plants that express these VSR genes. I also studied the gene expression changes related to the expression of the whole genome of Tobacco mosaic virus (TMV) in transgenic tobacco plants. Expression of the VSR genes in the transgenic tobacco plants causes significant changes in the gene expression profiles. HC-Pro gene derived from the Potyvirus Y (PVY) causes alteration of 748 and 332 transcripts, AC2 gene derived from the African cassava mosaic virus (ACMV) causes alteration of 1118 and 251transcripts, and P25 gene derived from the Potyvirus X (PVX) causes alterations of 1355 and 64 transcripts in leaves and flowers, respectively. All three VSRs cause similar up-regulation in defense, hormonally regulated and different stress-related genes and down-regulation in the photosynthesis and starch metabolism related genes. They also induce alterations that are specific to each viral VSR. The phenotype and transcriptome alterations of the HC-Pro expressing transgenic plants are similar to those observed in some Potyvirus-infected plants. The plants show increased protein degradation, which may be due to the HC-Pro cysteine endopeptidase and thioredoxin activities. The AC2-expressing transgenic plants show a similar phenotype and gene expression pattern as HC-Pro-expressing plants, but also alter pathways related to jasmonic acid, ethylene and retrograde signaling. In the P25 expressing transgenic plants, high numbers of genes (total of 1355) were up-regulated in the leaves, compared to a very low number of down-regulated genes (total of 5). Despite of strong induction of the transcripts, only mild growth reduction and no other distinct phenotype was observed in these plants. As an example of whole virus interactions with its host, I also studied gene expression changes caused by Tobacco mosaic virus (TMV) in tobacco host in three different conditions, i.e. in transgenic plants that are first resistant to the virus, and then become susceptible to it and in wild type plants naturally infected with this virus. The microarray analysis revealed up and down-regulation of 1362 and 1422 transcripts in the TMV resistant young transgenic plants, and up and down-regulation of a total of 1150 and 1200 transcripts, respectively, in the older plants, after the resistance break. Natural TMV infections in wild type plants caused up-regulation of 550 transcripts and down-regulation of 480 transcripts. 124 up-regulated and 29 down-regulated transcripts were commonly altered between young and old TMV transgenic plants, and only 6 up-regulated and none of the down-regulated transcripts were commonly altered in all three plants. During the resistant stage, the strong down-regulation in translation-related transcripts (total of 750 genes) was observed. Additionally, transcripts related to the hormones, protein degradation and defense pathways, cell division and stress were distinctly altered. All these alterations may contribute to the TMV resistance in the young transgenic plants, and the resistance may also be related to RNA silencing, despite of the low viral abundance and lack of viral siRNAs or TMV methylation activity in the plants.