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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Etograma e orçamento temporal de um grupo de machos não pareados de Phyllostomus hastatus (Pallas 1767) (Phyllostomidae: Phyllostominae) / Ethogram and time budget of a group of male bachelor phyllostomus hastatus (Pallas 1767) (phyllostomidae: Phyllostominae)

Aline Zimmermann Maya Simões 21 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Embora exista uma enorme variação de histórias de vida e ecologia, a maioria das espécies de morcegos mostra-se, em algum nível, social. Os aspectos de ecologia comportamental de quirópteros tem sido estudados, embora a maior parte refira-se a colônias de maternidades em regiões de clima temperado. Repertórios comportamentais completos e orçamentos temporais são raros, especialmente para a região Neotropical. Para compreender melhor a sociabilidade neste grupo, mostra-se importante focar também em grupos neutros com relação a fatores associados à atividade reprodutiva. Neste sentido, o estudo de grupos de machos neotropicais pode apresentar respostas importantes. O comportamento de um grupo machos não pareados de Phyllostomus hastatus foi estudado dentro do seu abrigo por aproximadamente 100 horas entre os meses de janeiro e agosto de 2012. O grupo estava abrigado no forro de um telhado de uma casa em desuso da Vila Dois Rios, na Ilha Grande. Os comportamentos foram registrados com uma câmera sensível a infra-infravermelho Sony DCR-HC28 em modo night-vision. Quando necessário, utilizei uma luz de auxílio infravermelha. A partir dos vídeos eu elaborei primeiramente um etograma. Os comportamentos classificados como estados foram usados para fazer um orçamento temporal, usando metodologia de amostragem por varredura e amostragem instantânea. Adicionalmente, fiz algumas observações a respeito de horário de entrada e saída dos morcegos e do tamanho do grupo. Organizei os comportamentos em seis categorias, com um total de 24 comportamentos distintos. Os comportamentos descritos são consistentes com os publicados em outros etogramas de morcegos, inclusive de alguns megaquirópteros. Um comportamento mais notável foi ventilando, que parece raro entre os microquirópteros, mas provavelmente importante na termorregulação. Nos meses analisados os morcegos alocaram aproximadamente 50% do tempo ao estado dormindo; 14,6% ao estado parado; 15,3% ao estado ativo; 0,9% ao estado andando; 0,1% ao estado voando; 14,1% ao estado higiene; e 3,5% ao estado ventilando. O orçamento temporal foi semelhante aos descritos para outros microquirópteros no interior de abrigos, com uma maior prevalência do estado dormindo, e com picos de atividade (principalmente do estado higiene) antes e depois das saídas noturnas. A higiene parece ter um papel importante no controle de ectoparasitas, e talvez algum papel social, mas como a higiene de outros indivíduos só foi observada uma única vez, não pude concluir nada a respeito. O presente trabalho é o primeiro etograma para Phyllostomus hastatus e o primeiro etograma e orçamento temporal para um grupo de machos em Chiroptera. Observei algumas diferenças importantes do grupo estudado com trabalhos já publicados sobre essa espécie, e sugiro que essas diferenças sejam estudadas mais a fundo. Apesar desta dissertação trazer contribuições importantes, fica claro que ainda falta muito a ser examinado nesse campo. / Even though bats have an enormous variation in ecology and life history traits, most of them are, to some level, social. Aspects of bat behavioral ecology are being studied, but most of the studies are focused on maternity colonies of temperate climate. Behavioral repertoires and time budgets are especially rare, and even more so in the Neotropics. To completely understand sociality in this group, it is not enough to study only maternity colonies, it is important to focus on groups that are neutral to factors related to reproduction. In this sense, the study of Neotropical male groups can bring us important answers. The behavior of a group of bachelor males of Phyllostomus hastatus was studied in their roost for approximately 100 hours between January and August 2012. They were roosting in the attic of an unused house in the villa of Dois Rios, in Ilha Grande, Brazil. The behaviors were recorded using and an infrared Sony DCR-HC28 in night-vision mode. When necessary, I used an infrared light source. From the videos I was able to construct an ethogram. The behaviors listed as states where afterwards used to make the time budget using scan sampling and instantaneous sampling. Additionally, I made some observations on the emergence time and group size. I organized the behaviors in six categories, with a total of 24 different behaviors. The behaviors described are consistent with other bat ethograms published, including a few Megachiroptera. One behavior that was most notable was wing fanning, that seems rare among microbats, and is probably important in temperature regulation. In the months analyzed, the bats spent around 50% of their time sleeping; 14,6% in the state still; 15,3% active; 0,9% crawling; 0,1% flying; 14,1% grooming; and 3,5% in the state wing fanning. The time budget was similar to those described for other Microchiroptera in their roosts, with a prevalence of sleeping and activity spikes before and after night emergence (especially in grooming). Grooming apparently has in important role in ectoparasite control, and maybe also a social role. But since social grooming was only seen once, I cannot conclude anything in that matter. The present work is the first ethogram for Phyllostomus hastatus and the first ethogram and time budget for a group of male bats. I observed some important differences between the groups studied here and the published works on bats from the same species, and suggest these be looked at more carefully. Even though this dissertation brings some important contributions, it highlights the need for more to been done in this field.
72

Conservação de morcegos no estado do Rio de Janeiro: como e onde já foram amostrados e que locais merecem atenção / Bats conservation in Rio de Janeiro state: how and where have already been sampled and localities that deserve attention

Luciana de Moraes Costa 11 February 2014 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / A demarcação de Unidades de Conservação é uma forma supostamente eficaz para a conservação da biodiversidade. A Mata Atlântica é caracterizada por apresentar uma elevada biodiversidade e altos níveis de ameaça. O estado do Rio de Janeiro encontra-se totalmente inserido nesse bioma e seus remanescentes florestais são considerados um hotspot dentro de outro hotspot. O Rio de Janeiro pode ser considerado um dos estados melhor amostrados, porém ainda existem lacunas de conhecimentos geográficos sobre a ocorrência de morcegos. Esta tese foi desenvolvida em três capítulos com o objetivo de contribuir com conservação de morcegos no estado do Rio de Janeiro, focando em como e onde eles já foram amostrados e que locais ainda carecem de atenção. Para este estudo foram utilizados dados referentes a buscas bibliográficas e dados de amostragens do Laboratório de Diversidade de Morcegos da Universidade Federal Rural do Rio de Janeiro. No primeiro capítulo pode-se observar que as localidades com mais de 30 espécies de morcegos são resultado de grande esforço de captura e amostragens usando diversas metodologias. Para uma melhor amostragem da riqueza local, devem-se armar redes não somente em trilhas e próximas a árvores em frutificação, mas também sobre corpos de água. Fazer busca em refúgios diurnos também é aconselhável. Devem ser realizadas amostragens durante a noite toda e variar a fase do ciclo lunar, não restringindo a apenas uma ou partes das fases do ciclo lunar. No segundo capítulo observou-se que 43% das Unidades de Conservação aqui estudadas apresentam 20 ou mais espécies. Localidades que apresentam de 20 a 40 espécies de morcegos na Mata Atlântica podem ser consideradas bem amostradas. Isso demonstra que mais da metade das Unidades de Conservação não podem ser consideradas bem inventariadas. Muitos projetos de pesquisas dão prioridade para a localidade estudada ser uma Unidade de Conservação, porém existem poucos trabalhos de longa duração. No Rio de Janeiro ainda existem diversas Unidades de Conservação não amostradas, principalmente aquelas de difícil acesso e em altitudes elevadas. No terceiro capítulo foi possível observar que há uma maior proporção de espécies que apresentam distribuição geográfica restrita. Esse padrão constitui uma informação importante em termos de conservação, visto que indiretamente poderia indicar uma menor capacidade de dispersão desses animais em médias e grandes distâncias. Entretanto existem lacunas de conhecimento em decorrência da falta de amostragem em algumas regiões, sendo imperativos maiores esforços de captura. Importantes municípios para a conservação e/ou preservação de morcegos como Varre-Sai, Cambuci, Miracema, Carmo, Cantagalo, Valença, Barra do Piraí e Piraí não estão sob proteção legal, mesmo constituindo possíveis corredores entre Unidades de Conservação ou mesmo fragmentos importantes que ainda detém espécies que não estão representadas em Unidades de Conservação já estabelecidas. É imperativo que mais estudos e esforços de conservação sejam direcionados para essas áreas / The establishment of Conservation Units is a supposedly effective way for the biodiversity conservation. The Atlantic Forest is characterized by having a high biodiversity and high levels of threat. The Rio de Janeiro state is fully inserted in this biome and its forest remnants are considered hotspots inside another hotspot. Rio de Janeiro may be considered one of the best-sampled states, but there are still gaps in knowledge about the geographic occurrence of bats. This thesis was developed in three chapters with the purpose of contributing to the bats conservation in Rio de Janeiro state, focusing on how and where they have already been sampled and sites that still require attention. For this study were used data from literature searches and data sampling from the Laboratório de Diversidade de Morcegos of Universidade Federal Rural do Rio de Janeiro. The first chapter shows that the localities with more than 30 bats species are the result of high capture effort and samplings using several methodologies. For a better sampling of local richness, mist nets must be armed not only on trails and near fruiting trees, but also over bodies of water. Diurnal roosts searches is also advisable. Samplings must be performed throughout all the night and vary the lunar phase cycle, not just one or restricted phases of the lunar cycle. In the second chapter was observed that 43% of the protected areas from these study presented 20 or more species. Localities presenting 20 to 40 bat species in the Atlantic could be considered well sampled. It demonstrates that over half of the protected areas can not be considered well sampled. Many research projects prioritize the conservation units localities, but there are few long-term studies. In Rio de Janeiro state, there are still several unsampled Conservation Units, especially those with difficult access and high altitudes. In the third chapter was observed that there is a higher proportion of species with restricted geographical distribution. This pattern is an important information in terms of conservation, as this might indirectly indicate a lower dispersal ability of these animals in medium and large distances. However, there are gaps in knowledge due to lack of studies in some areas, where further capture efforts are needed. Important municipalities for conservation and/or preservation of bats as Varre-Sai, Cambuci, Miracema, Carmo, Cantagalo, Valença, Barra do Piraí e Piraí and are not under legal protection, even being possible corridors between protected areas or even important fragments that still holds species, which are not represented in Conservation Units already established. It is imperative that more studies and conservation efforts are directed to these areas
73

Systématique, phylogénie et évolution moléculaires des Phyllostomidae (Mammalia, Chiroptera) : une approche mitogénomique comparative / Molecular systematics, phylogenetics and evolution of Phyllostomid bats (Mammalia, Chiroptera) : a mitogenomic approach using high-throughput sequencing technologies

Botero-Castro, Fidel 12 December 2014 (has links)
L'acquisition des données moléculaires a été bouleversée par le développement des techniques de séquençage haut-débit. Celles-ci ont augmenté la quantité des données et ont fait diminuer le coût de manière considérable. Ces nouvelles approches ont également redonné accès à des sources de matériel biologique qui étaient auparavant inutilisables en raison de la faible quantité et la forte dégradation de l'ADN qu'elles fournissent, notamment des tissus anciens, des échantillons de musée voire du matériel fossile. Un avantage supplémentaire c'est la possibilité de multiplexer les échantillons, c'est-à-dire, les mélanger et les séquencer simultanément grâce à l'utilisation de « tags » ou étiquettes permettant de les séparer après avec des outils bioinformatiques. Un marqueur qui a grandement bénéficié de ces technologies est le génome mitochondrial. En effet, nous montrons que grâce au ratio élevé entre l'ADN mitochondrial et l'ADN nucléaire par cellule, il est possible l'obtention de mitogénomes entiers, avec de couvertures adéquates, sans qu'un enrichissement préalable de l'échantillon soit nécessaire. Ceci permet d'envisager la réalisation de projets de mitogénomique comparative pour de groupes riches en espèces, requérant un échantillonnage taxonomique exhaustif et dont les divergences génétiques rendrait difficile l'usage du séquençage classique. C'est dans ce contexte que cette thèse aborde la systématique, la phylogénie et l'évolution moléculaires d'une famille de chauves-souris néotropicales : les Phyllostomidae. Cette famille est riche en espèces, avec plus de 160 taxons mais aussi en traits d'histoire de vie contrastés notamment le régime alimentaire. Cette diversité résulte en des morphologies convergentes dont les caractères sont en conséquence peu appropriés pour reconstruire l'histoire évolutive de ce groupe. La mitogénomique a prouvé être un outil efficace dans ce dessein, mais à présent aucune étude de ce type a été conduite pour cette famille. Nous avons d'abord réussi à séquencer les mitogénomes de représentants de toutes les lignées majeures couvrant également la diversité de traits d'histoire de vie. Nous montrons ensuite que l'utilisation de ces mitogénomes permet de résoudre les relations de parenté au niveau intrafamilial avec une résolution similaire à celle d'une concaténation de marqueurs mitochondriaux et nucléaires avec un soutien statistique robuste pour la plupart des nœuds de la phylogénie. Ceci nous a permis de clarifier plusieurs relations qui restaient controversées dans des études précédentes et confirmer plusieurs des clades proposés par celles-ci. Ensuite, nous abordons l'évolution du mitogénome en relation avec les traits d'histoire de vie en utilisant comme exemple le clade des vampires, les seules Mammifères hématophages, dont le génome mitochondrial semble avoir été touché par une accélération du taux d'évolution comme conséquence de l'action combinée de forces neutres et sélectives pour répondre aux contraintes imposées par ce régime alimentaire. Finalement, le cadre phylogénétique robuste proportionné par les 100 mitogénomes que nous avons séquencés pourra être utilisé comme référence pour étudier la diversification des Phyllostomidae. / New sequencing technologies have revolutionized the acquisition of molecular data by increasing the amount of sequences at a considerably lower cost. These new technologies have also given access to samples previously neglected because they resulted in low-quantity and degraded DNA yields, as for example, old tissues, museum specimens and even fossil rests. An additional advantage comes from the possibility of multiplexing; this is, mixing several taxa in a single sample thanks to the use of tags or labels allowing late separating the sequences using bioinformatic tools. A molecular marker that has greatly benefited from these technologies is the mitochondrial genome. Indeed, we show that, thanks to the high per-cell ratio of mitochondrial to nuclear DNA, it's possible to obtain whole well-covered mitochondrial genomes without previous sample enrichment. This allows the accomplishment of projects of comparative mitogenomics for species-rich groups needing exhaustive taxon sampling and for which strong genetic divergences would difficult the use of classical sequencing.It is in this context that this thesis tackles the molecular systematics, phylogenetics and evolution of a Neotropical family of bats: the Phyllostomidae. This species-rich family, accounting for more than 160 species, is also the family of Mammals with the highest diversity of life history traits, for example, feeding on almost every possible source of food. This diversity results in convergent morphologies that make this kind of characters inadequate for reconstructing the evolutionary history of this group. Mitogenomics has proven useful in similar cases but no study of this kind has been conducted for this family. We got to sequence whole mitogenomes for representatives of all major lineages and covering the diversity of life history traits. We then show that using these mitogenomes allows solving intrafamilial relationships with a resolution similar to that resulting from a concatenation of mitochondrial and nuclear markers and with solid statistical support for most of the nodes of the phylogeny. This allowed clarifying several controversial relationships and confirming several clades proposed in previous studies. Next, we illustrate the evolution of mitogenomes and the influence of life history traits using the clade of vampire bats, the only hematophagous Mammals, whose mitogenome seem to have undergone an acceleration of evolutionary rate as a consequence of the combined action of neutral and selective forces in order to counter the constraints imposed by this feeding habit. Finally, the robust phylogenetic frame provided by the 100 mitogenomes that we sequenced, will be used for future studies about, for exemple, the diversification process of Phyllostomids.
74

Hur påverkas fladdermöss av bytet till LED från traditionella ljuskällor? : En jämförelse mellan olika ljuskällors påverkan på fyra arter av fladdermöss i Karlstads kommun / How are bats affected by the switch to LEDs from traditional light sources? : A comparison between different light sources and its impacts on four species of bats in Karlstad Municipality, Sweden

Lehikoinen, Jennifer January 2023 (has links)
Ljusföroreningar är ett stort framväxande problem och då fladdermöss oftast är nattaktiva erfaras de ingå i den taxa som påverkas mest. LED-belysning blir allt vanligare i gatubelysning och utstrålar bland annat inget UV-ljus jämfört med traditionella ljuskällor som utstrålar UV-ljus och därmed förändrar insekters- och potentiellt fladdermössens beteende. Det var därför relevant att undersöka hur den stod sig till traditionella ljuskällor med avseende på ekologisk påverkan. Med anledning av ett stort utbyte till LED i Karlstads kommun 2019 gavs en möjlighet att jämföra påverkan på fladdermöss utifrån olika ljuskällor. Syftet med studien var att undersöka om bytet till LED från traditionella ljuskällor skulle kunna ha en lägre påverkan på fladdermöss i Karlstads kommun och ifall en skillnad mellan arter kunde påvisas. Studien grundade sig i observationsdata hämtad från Fyndkartor via Artportalen, kartskikt från modelleringsverktyget PREBAT och kommunens belysningslager. Vidare har hänsyn tagits till födotillgång, avståndet till- och antalet boplatser, utifrån uppskattningar av PREBAT. Studien fann en signifikant medelskillnad om ca. 20% lägre avstånd till belysning mellan åren före och efter bytet till LED-belysning. Samtliga arter av fladdermöss hade lägre avstånd till LED-belysning jämfört med övrig belysning, däremot var skillnaden inte signifikant. Ingen signifikant skillnad kunde påvisas mellan arter, även om de mer opportunistiska arterna hade lägre avstånd till samtliga ljuskällor. Vidare kunde inte boplatsernas avstånd eller antal förklaras som en bidragande faktor till det låga avståndet till LED då fladdermössen inte visade en statistiskt signifikant ”preferens” för LED-belysning. Denna studie överensstämmer med tidigare forskning som säger att artificiell belysning påverkar fladdermöss men huruvida LED-belysning skulle ha en mindre ekologisk påverkan på fladdermöss är ännu inte klarlagt. Däremot finns det många åtgärder som kan sättas in för att reducera den ekologiska påverkan som ljusföroreningar har på fladdermöss och andra nattaktiva djur. / Light pollution is a rapidly growing problem and since bats often are nocturnal, they appear to be one of the taxa that is most affected. LED-lighting is becoming more common in street lighting, and it emits less UV light than traditional mercury lights, altering insect and potentially bat behavior. Thus, it is relevant to investigate LED-lighting compared to traditional light sources, in terms of the ecological impact. Owing to a large-scale switch to LED-lighting in Karlstad Municipality in 2019, there was an opportunity to compare the impact of different light sources on bats. The purpose of this study was to investigate if the switch to LEDs from traditional light sources could have a lower impact on bats in Karlstad, and to test if there were differences among species. The data in this study was based on observations from “Fyndkartor” at “Artportalen”, map layers from the PREBAT modeling software, and a map layer of the municipality’s street lighting. Consideration has been given to food supply, the distance to- and the amount of roosting sites, as estimated by the PREBAT model. The study found a significant mean difference of ca. 20% less distance to lighting between years before and after LED light installation. Each one of the four bat species had a lower distance to LED-lighting, compared to traditional lighting, but these differences were not significant. No significant difference was found among species, even though the more opportunistic species had a lower distance to each one of the light sources, as has been found in other studies. Furthermore, the distance to, or amount of, roosting sites could not explain why bats had a lower distance to LED-lighting, since the bats did not show a “preference” to LED that was statistically significant. This study is in line with previous research that confirms that artificial lighting has an impact on bats, but whether LED-lighting has a lower impact than other light sources still remains unclear. There are, however, many measures to be taken to reduce the ecological impacts that light pollution has on bats and other nocturnal animals.
75

Evolution of major histocompatibility complex genes in New World bats and their functional importance in parasite resistance and life-history decisions in the lesser bulldog bat (Noctilio albiventris)

Schad, Julia January 2012 (has links)
Immune genes of the major histocompatibility complex (MHC) constitute a central component of the adaptive immune system and play an essential role in parasite resistance and associated life-history strategies. In addition to pathogen-mediated selection also sexual selection mechanisms have been identified as the main drivers of the typically-observed high levels of polymorphism in functionally important parts of the MHC. The recognition of the individual MHC constitution is presumed to be mediated through olfactory cues. Indeed, MHC genes are in physical linkage with olfactory receptor genes and alter the individual body odour. Moreover, they are expressed on sperm and trophoplast cells. Thus, MHC-mediated sexual selection processes might not only act in direct mate choice decisions, but also through cryptic processes during reproduction. Bats (Chiroptera) represent the second largest mammalian order and have been identified as important vectors of newly emerging infectious diseases affecting humans and wildlife. In addition, they are interesting study subjects in evolutionary ecology in the context of olfactory communication, mate choice and associated fitness benefits. Thus, it is surprising that Chiroptera belong to the least studied mammalian taxa in terms of their MHC evolution. In my doctoral thesis I aimed to gain insights in the evolution and diversity pattern of functional MHC genes in some of the major New World bat families by establishing species-specific primers through genome-walking into unknown flanking parts of familiar sites. Further, I took a free-ranging population of the lesser bulldog bat (Noctilio albiventris) in Panama as an example to understand the functional importance of the individual MHC constitution in parasite resistance and reproduction as well as the possible underlying selective forces shaping the observed diversity. My studies indicated that the typical MHC characteristics observed in other mammalian orders, like evidence for balancing and positive selection as well as recombination and gene conversion events, are also present in bats shaping their MHC diversity. I found a wide range of copy number variation of expressed DRB loci in the investigated species. In Saccopteryx bilineata, a species with a highly developed olfactory communication system, I found an exceptionally high number of MHC loci duplications generating high levels of variability at the individual level, which has never been described for any other mammalian species so far. My studies included for the first time phylogenetic relationships of MHC genes in bats and I found signs for a family-specific independent mode of evolution of duplicated genes, regardless whether the highly variable exon 2 (coding for the antigen binding region of the molecule) or more conserved exons (3, 4; encoding protein stabilizing parts) were considered indicating a monophyletic origin of duplicated loci within families. This result questions the general assumed pattern of MHC evolution in mammals where duplicated genes of different families usually cluster together suggesting that duplication occurred before speciation took place, which implies a trans-species mode of evolution. However, I found a trans-species mode of evolution within genera (Noctilio, Myotis) based on exon 2 signified by an intermingled clustering of DRB alleles. The gained knowledge on MHC sequence evolution in major New World bat families will facilitate future MHC investigations in this order. In the N. albiventris study population, the single expressed MHC class II DRB gene showed high sequence polymorphism, moderate allelic variability and high levels of population-wide heterozygosity. Whereas demographic processes had minor relevance in shaping the diversity pattern, I found clear evidence for parasite-mediated selection. This was evident by historical positive Darwinian selection maintaining diversity in the functionally important antigen binding sites, and by specific MHC alleles which were associated with low and high ectoparasite burden according to predictions of the ‘frequency dependent selection hypothesis’. Parasite resistance has been suggested to play an important role in mediating costly life history trade-offs leading to e.g. MHC- mediated benefits in sexual selection. The ‘good genes model’ predicts that males with a genetically well-adapted immune system in defending harmful parasites have the ability to allocate more resources to reproductive effort. I found support for this prediction since non-reproductive adult N. albiventris males carried more often an allele associated with high parasite loads, which differentiated them genetically from reproductively active males as well as from subadults, indicating a reduced transmission of this allele in subsequent generations. In addition, they suffered from increased ectoparasite burden which presumably reduced resources to invest in reproduction. Another sign for sexual selection was the observation of gender-specific difference in heterozygosity, with females showing lower levels of heterozygosity than males. This signifies that the sexes differ in their selection pressures, presumably through MHC-mediated molecular processes during reproduction resulting in a male specific heterozygosity advantage. My data make clear that parasite-mediated selection and sexual selection are interactive and operate together to form diversity at the MHC. Furthermore, my thesis is one of the rare studies contributing to fill the gap between MHC-mediated effects on co-evolutionary processes in parasite-host-interactions and on aspects of life-history evolution. / Innerhalb des adaptiven Immunsystems spielen die Gene des MHC (Major Histocompatibility Complex) eine zentrale Rolle. Neben ihrer Funktion für die körpereigene Parasitenabwehr haben sie auch einen entscheidenden Einfluss auf damit verbundene ‚life-history’ Strategien. Typischerweise sind die funktional für die Pathogenerkennung wichtigen Genabschnitte hoch variabel, was evolutiv nicht nur durch die Vielfalt der Pathogene bedingt ist, sondern im Zuge der sexuellen Selektion durch entsprechende Partnerwahl gefördert wird. Dabei wird die individuelle MHC-Konstitution sehr wahrscheinlich über körpereigene Duftstoffe vermittelt, denn MHC Gene bestimmen nicht nur den individuellen Körpergeruch, sondern liegen in chromosomaler Kopplung mit olfaktorischen Rezeptorgenen. Außerdem werden sie auch auf Sperma- und Trophoplastenzellen exprimiert, so dass MHC-bedingte sexuelle Selektionsmechanismen nicht nur über die direkte Partnerwahl, sondern auch durch kryptische Mechanismen während der Fortpflanzung wirken können. Fledermäuse und Flughunde (Chiroptera) bilden die zweitgrößte Säugetiergruppe und gelten als wichtiges Reservoir und Überträger für den Menschen und andere Wildtiere hoch infektiöser Krankheiten. Innerhalb der evolutionären Ökologie sind sie außerdem auf Grund ihrer z.T. komplexen olfaktorischen Kommunikation während der Partner-wahl und den damit verbundenen fitness relevanten Vorteilen interessante Forschungsobjekte. In Anbetracht dessen ist es erstaunlich, dass bisher so gut wie nichts über den MHC in dieser Säugergruppe bekannt ist. Das Ziel meiner Dissertation war es, zum einen Einblicke in die Evolution und Diversität funktional wichtiger MHC Gene (MHC Klasse II DRB) bei Fledermäusen zu erhalten, und zum anderen zu untersuchen, inwieweit die individuelle MHC-Konstitution am Beispiel der kleinen Hasenmaulfledermaus (Noctilio albiventris) einen Einfluss auf Parasitenresistenz und Fortpflanzung hat und welche Selektionsmechanismen dabei für das entstandene genetische Diversitätsmuster verantwortlich sind. Meine Arbeit zeigt, dass Prozesse, die bei anderen Vertebratenordnungen das Diversitätsmuster am MHC hervorrufen, wie balancierende und positive Selektion, Rekombination und Genkonversion ebenfalls für Fledermäuse zutreffen. In der Anzahl exprimierter DRB loci unterscheiden sich die untersuchten Fledermausarten allerdings beträchtlich. Bemerkenswert ist die extrem hohe Anzahl DRB loci bei Saccopteryx bilineata, die in dieser Ausprägung noch bei keiner anderen Säugetierart beschrieben wurde, einer Fledermaus mit einem hoch entwickelten olfaktorischen Kommunikations-system. Die hier erstmals durchgeführten phylogenetischen Untersuchungen zeigen, dass sich anders als für die meisten anderen Säugetiergruppen beschrieben, die duplizierten DRB Loci unabhängig voneinander entwickelt haben. Dieser mono-phyletische Ursprung duplizierter Loci innerhalb von Fledermausfamilien bestätigte sich für alle Bereiche des Genes: dem hochvariablen Exon 2, das für den funktional entscheidenden Pathogen-bindenden Bereich des Proteins kodiert, sowie für Exon 3 und 4, die für die Molekülstruktur erhaltende Bereiche des Proteins kodieren. Innerhalb der Gattungen (Noctilio, Myotis), basierend auf Exon 2, fand ich das für andere Säugergruppen typische Bild eines ‚trans-species polymorphism’, bei dem MHC-Allele von verschiedenen Arten sich untereinander ähnlicher sein können als Allele der gleichen Art. Meine Ergebnisse sind ein wichtiger Beitrag zum Verständnis der MHC Evolution in der Gruppe der Fledermäuse und liefern hilfreiche Kenntnisse für zukünftige Studien zum MHC in dieser Säugetierordnung. Meine Studien an einer frei lebenden Population der kleinen Hasenmaulfledermaus zeigten dass der exprimierte DRB Locus typische Anzeichen pathogenbedingter aber auch sexueller Selektionsmechanismen zeigt. Ich fand eine ausgeprägte populations-weite Heterozygotie, positive darwinsche Selektion, die den Polymorphismus in Codons die direkt an der Pathogenerkennung beteiligt sind erhält, sowie spezifische Allele die entweder mit einer erhöhten oder einer geringen Parasitenbelastung einhergehen, entsprechend den Annahmen der ‚Frequenz-abhängigen Selektions-Hypothese’. Die individuelle Parasitenresistenz gilt als ein wichtiger Faktor um ressourceabhängige ‚life-history’ Strategien auszuloten. Vor allem Männchen mit einem effektiven Immunsystem, sollten mehr Energien für die Fortpflanzung zur Verfügung haben (‚good-genes model’). Meine Daten bestätigen diese Annahme, Männchen die stärker parasitisiert waren, waren weniger häufig reproduktiv aktiv und trugen häufiger ein DRB-Allele das mit erhöhter Parasitenbelastung einherging. Genetisch unterschieden sie sich darin nicht nur von den reproduktiv aktiven Männchen der Population sondern auch von den Jungtieren. Die Jungtiere trugen zudem häufiger ein für die Parasitenabwehr vorteilhaftes Allel. Die Ergebnisse zeigen dass die individuelle MHC-Konstitution einen nicht zu unterschätzenden Einfluss auch auf den Reproduktionserfolg eines Männchens haben kann und vorteilhafte Allele sich bereits in nachfolgenden Generationen durchsetzen. Meine Doktorarbeit gehört damit zu einer der seltenen Studien, die nicht nur zeigen konnte inwieweit der MHC an co-evolutionären Prozessen der Parasit-Wirt-Interaktion beteiligt ist, sondern dass er darüber hinaus auch direkt für die individuelle ‚life-history’ Entwicklung von Bedeutung ist.
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Prioridades globais para a conservação e características biológicas associadas ao risco de extinção em morcegos (Chiroptera:mammalia) / Global conservation priorities and biological traits related to extinction risks in bats.

MENDES, Poliana 04 March 2011 (has links)
Made available in DSpace on 2014-07-29T16:21:16Z (GMT). No. of bitstreams: 1 dissertacao Poliana Mendes.pdf: 900873 bytes, checksum: 549aa0a8671a1a0cdfa3dc72f555ddc7 (MD5) Previous issue date: 2011-03-04 / The species loss in recent decades can be comparable to a mass extinction event. This scenario emphasizes the need for biodiversity conservation before it disappears, but the resources devoted to this purpose are limited. In this context, identifying species that possess characteristics that predispose them to a greater sensitivity to environmental changes may help understanding how species losses occur. In addition, proposals for conservation strategies from existing knowledge about species are practical ways of minimizing the loss of biodiversity. The greater ecological diversity of the order Chiroptera, when compared with other groups of mammals, suggests that this may be a good study group to research in conservation biology. In this scenario, Chapter 1 uses a scoring methodology that considered four parameters to define priorities for conservation of bats: risk of extinction, endemism, originality and the public interest. Later, we checked if priority species and areas are covered by any protected areas. It was also verified if priority areas for bats are more congruent with global priorities, focused on pro-active or reactive strategies. The three species with the highest score for conservation priority were Acerodon humilis, Acerodon jubatus and Latidens salimali. The priority areas for bat conservation are in South Amercia, Madagascar, some spots in Africa, Australia, New Zealand and Indonesian Islands. The sites covered by reactive strategies have greater priority level for conservation of bats, but we observed both reactive and pro-active strategies, within priority boxes. Only one quarter of the priority squares for bats have 10% or more of conserved areas within I-IV criteria, idealized values for 2010 Conservation Biodiversity (CBD). The results suggest that tropical areas, which also have more species of bats, are the ones that require more attention from conservation programs and much of these areas are minimally represented by conservation units, emphasizing the importance of investments for biodiversity conservation in these locations. Both reactive and pro-active strategies are important for biodiversity maintenance of bats, despite the reactive strategies being more representative in grid cells with the highest values of priority. In chapter 2, we checked if there is a relationship between bats biological features and extinction risk. Features used were: body mass, litter size, forearm size, wing length, gestational length and age of sexual maturity. Since the relationship between these features and the risk of extinction may be biased by phylogenetic relationships, we used a Phylogenetic Eigenvectors regression analysis (PVR) to remove the phylogenetic components of predictors. All variables addressed except gestational length are phylogenetically structured. Body mass, forearm length, wing length and litter size are related to the extinction risk. Since higher residual values for body mass and forearm size are associated with extinction risk and lower residual values for wing length and litter size are more related to the extinction risk. Smaller wing length as predictor of extinction risk may be associated with the species largest mobility capacity with larger wings. Body mass is a commonly associated feature with extinction risk, and this relationship can be explained by the relationship of this variable with slow life history features, higher species threat due to hunting, greater environmental resource acquisition or larger life area. Despite the small body size in mammals is associated with the lower extinction risk, bats unlike most small mammals have a slow life history, a factor that increases the susceptibility to species extinction. / A perda de espécies das últimas décadas é equiparável a um evento de extinção em massa. Esse cenário enfatiza a necessidade da conservação da biodiversidade antes que ela desapareça, porém os recursos destinados a esse propósito são limitados. Sob esse contexto, identificar espécies que possuem características que as predispõe a uma maior sensibilidade a alterações ambientais pode auxiliar no entendimento de como ocorre a perda de espécies. Além disso, propostas de estratégias de conservação, a partir do conhecimento já existente sobre as espécies, são maneiras práticas de tentar minimizar a perda da biodiversidade. A grande diversidade ecológica da ordem Chiroptera, quando comparada com outros grupos de mamíferos, sugere que este pode ser um bom grupo de estudo para a pesquisa em biologia da conservação. Diante deste cenário, no Capítulo 1 utilizamos uma metodologia de pontuação que considerou quatro parâmetros para definir prioridades de conservação para morcegos: risco de extinção, endemismo, originalidade e interesse público. Posteriormente, verificamos se áreas e espécies prioritárias são cobertas por alguma área protegida. Foi também verificado se as áreas prioritárias para morcegos são mais congruentes com prioridades globais, focadas em estratégias proativas ou reativas. As três espécies com maior pontuação de prioridade de conservação foram Acerodon humilis, Acerodon jubatus e Latidens salimali. As áreas prioritárias para a conservação de morcegos estão na América do Sul, Madagascar, alguns locais na África, Austrália, Nova Zelândia e Ilhas da Indonésia. Os locais cobertos por estratégias reativas possuem maior valor de prioridade de conservação para morcegos, porém observamos tanto estratégias proativas quanto reativas, dentre as quadrículas prioritárias. Somente um quarto das quadrículas prioritárias para morcegos possuem 10% ou mais de áreas preservadas dentro dos critérios de I a IV, valor idealizado para 2010 na Convenção da Biodiversidade (CBD). Os resultados obtidos sugerem que as áreas tropicais, onde também existem mais espécies de morcegos, são as que necessitam mais atenção dos programas de conservação e grande parte destas áreas ainda não estão minimamente representadas por unidades de conservação, enfatizando a importância de investimentos para a conservação da biodiversidade nesses locais. Tanto estratégias de conservação reativas como proativas são importantes para manter a biodiversidade prioritária de morcegos, apesar das estratégias reativas serem mais representativas nas quadrículas com os maiores valores de prioridade. No Capítulo 2 verificamos se há relação entre características biológicas dos morcegos e o risco de extinção. As características utilizadas foram: massa corporal, tamanho da ninhada, tamanho do antebraço, comprimento da asa, duração da gestação e idade da maturidade sexual. Como a relação entre essas características e o risco de extinção pode estar enviesada pelas relações filogenéticas, utilizamos uma Análise de Regressão por Autovetores Filogenéticos (PVR) para retirar o componente filogenético das variáveis preditoras. Todas as variáveis abordadas, exceto duração da gestação estão estruturadas filogeneticamente. Massa corporal, tamanho do antebraço, comprimento da asa e tamanho da ninhada estão relacionados com o risco de extinção. Sendo que maiores valores residuais para massa corporal e tamanho do antebraço estão relacionados com o risco de extinção e menores valores residuais para comprimento da asa e tamanho da ninhada estão mais relacionados com o risco de extinção. Menores comprimentos da asa como preditor do risco de extinção pode estar associado com a maior capacidade de locomoção de espécies com maiores asas. A massa corporal é uma característica comumente associada com o risco de extinção, e essa relação pode ser explicada através da relação desta variável com características relacionadas a uma história de vida lenta, maior ameaça das espécies maiores devido a caça, maior aquisição de recursos do ambiente ou maior área de vida. Apesar do pequeno tamanho corporal em mamíferos ser associado com menor risco de extinção, os morcegos ao contrário da maioria dos mamíferos de pequeno porte, possuem história de vida lenta, fator que aumenta a predisposição de espécies à extinção. Os resultados deste estudo mostram que é possível utilizar características intrínsecas das espécies para predizer o risco de extinção, e isso pode ser útil para estabelecer estratégias de conservação para espécies classificadas como Deficientes de Dados, pois devido a suas características elas podem ser aproximadas das espécies ameaçadas ou não ameaçadas. Além disso, é possível propor estratégias para estabelecer prioridades de conservação de forma simples através da metodologia de pontuação, apesar da arbitrariedade dessa metodologia ao definir as pontuações para cada parâmetro.
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Determinantes ecológicos, evolutivos e histórico-biogeográficos dos padrões de diversidade de mamíferos terrestres em diferentes escalas / Ecological, evolutionary and historical biogeographical determinants of the terrestrial mammal diversity patterns in different scales

Peixoto, Franciele Parreira 31 March 2017 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-02T14:03:32Z No. of bitstreams: 2 Tese - Franciele Parreira Peixoto - 2017.pdf: 8334533 bytes, checksum: 7734e779e227ff5ab84bc8cfc9f9212b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-02T14:03:58Z (GMT) No. of bitstreams: 2 Tese - Franciele Parreira Peixoto - 2017.pdf: 8334533 bytes, checksum: 7734e779e227ff5ab84bc8cfc9f9212b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-02T14:03:58Z (GMT). No. of bitstreams: 2 Tese - Franciele Parreira Peixoto - 2017.pdf: 8334533 bytes, checksum: 7734e779e227ff5ab84bc8cfc9f9212b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-31 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The concept of ecological niche describes the set of biotic and abiotic conditions for which the species can maintain populations and define the species geographical range. The ecological niche is multidimensional, which means that is a function of several species characteristics. These characteristics can change fastly or can vary very slowly, remaining conserved throughout the evolutionary time, which characterizes the niche conservatism (i.e., the tendency of the species retaining the ancestral niche along the evolutionary time). Retaining the ancestral niche implies a smaller group capacity. Retaining the ancestral niche implies that the group is less able to adapt outside the distribution boundaries defined by the ecological niche. Therefore, the way that characteristics linked to the niche evolved along the time is determinant to generate differential patterns of diversity among taxa. In fact, niche conservatism has been raised as a relevant factor to explain the latitudinal gradient of diversity, as well as the biota formation of different habitats. Conservation of ecological tolerances implies an inheritance of a limited ability to colonize and establish in different habitats. On the other hand, some groups can be ecologically more flexible and colonize new habitats through the niche evolution, probably related to specific functional adaptations that allow the establishment of species. The objective of this work was to evaluate the diversity patterns of terrestrial mammals to infer about the main ecological, evolutionary and historical-biogeographical processes. / O conceito de nicho ecológico descreve o conjunto de condições bióticas e abióticas nas quais as espécies podem manter populações e define a área de distribuição das espécies. O nicho ecológico é multidimensional e, desse modo, é função de várias características das espécies. Essas características podem mudar rapidamente ou podem variar de forma muito lenta, permanecendo conservadas ao longo do tempo evolutivo, o que caracteriza a conservação de nicho (i.e., a tendência de as espécies manterem o nicho ancestral ao longo do tempo evolutivo). Reter o nicho ancestral implica em menor capacidade do grupo em se adaptar fora dos limites de distribuição definidos pelo nicho ecológico. Portanto, o modo como as características ligadas ao nicho evoluíram ao longo do tempo é determinante para gerar padrões diferenciais de diversidade entre táxons. De fato, a conservação de nicho tem sido levantada como fator relevante para explicar o gradiente latitudinal de diversidade, bem como a formação da biota de diferentes habitats. A conservação de tolerâncias ecológicas em algumas linhagens implica na herança de uma capacidade limitada de colonizar e se estabelecer em diferentes habitats. Por outro lado, alguns grupos podem ser ecologicamente mais flexíveis e colonizar novos habitats através da evolução de nicho, provavelmente relacionada a adaptações funcionais específicas que possibilitam o estabelecimento das espécies. Este trabalho teve como objetivo geral avaliar padrões de diversidade de mamíferos terrestres para inferir acerca dos principais processos ecológicos, evolutivos e histórico-biogeográficos atuantes. No primeiro capítulo, testei a hipótese de conservação de nicho climático (Grinnelliano) de Chiroptera. Encontrei fortes evidências de que a estase evolutiva pode ter sido importante para algumas famílias do grupo, o que chama a atenção para a importância da não-estacionariedade na evolução de nicho ambiental. No segundo capítulo, investiguei o gradiente global de dissimilaridade filogenética de mamíferos terrestres. Identifiquei regiões onde a perda de linhagens (diferença de diversidade filogenética) é o que determina o gradiente de dissimilaridade (transições com desertos e limites entre regiões biogeográficas), bem como regiões onde a troca de linhagens foi mais importante para gerar padrões de diversidade beta filogenética (elevadas altitudes). Esses padrões foram diferentes entre três ordens de mamíferos analisadas, demonstrando a importância da capacidade de dispersão e da capacidade de estabelecimento, possivelmente condicionada à evolução nicho. No terceiro capítulo, investiguei padrões locais de diversidade filogenética e funcional de mamíferos africanos. Concluí que a história de colonização e diversificação diferencial entre grupos de mamíferos parece estar relacionada com a flexibilidade ecológica e a habilidade de lidar com mudanças climáticas. De forma geral, os resultados dos três capítulos convergiram para a importância da história evolutiva de diferentes grupos taxonômicos (desde ordem até gênero e espécie) para compreender os padrões de diversidade atuais.
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The distribution and habitat preferences of bats in a temperate urban landscape

Lintott, P. R. January 2015 (has links)
Urbanisation is a key driver in the loss, fragmentation and modification of natural habitats resulting in the global loss of biodiversity. As the human population, and consequently the rate of urbanisation, continues to increase exponentially it is important to understand how to sustain and enhance biodiversity within the built environment. Cities comprise a complex assortment of habitat types yet relatively little is known of how its composition and spatial configuration can influence species presence or foraging activities. It is therefore necessary to examine habitat use and biodiversity patterns at multiple spatial scales to fully understand how species are responding to the urban matrix. There are few other orders of animals that are as strongly associated with people as bats (Chiroptera); for some bat species human habitations provide roosts and adaptations of the environment provide food sources. However bat species richness generally declines with increasing urbanisation indicating that many species are not able to persist in highly urbanised areas. In this thesis, I show that the behaviour, habitat preferences, and distribution of bats are strongly influenced by the built environment at both a local and landscape scale. Although many animal species are known to exhibit sex differences in habitat use, adaptability to the urban landscape is commonly examined at the species level without consideration of potential intraspecific differences. I found that female Pipistrellus pygmaeus show greater selectivity in foraging locations within urban woodland in comparison to males at both a local and landscape scale. There was a lower probability of finding females within woodlands which were poorly connected, highly cluttered, with a high edge: interior ratio and fewer mature trees. The results have important implications for our understanding of how to manage areas for breeding females and highlight the need to supplement acoustic monitoring with trapping data to assess sex differences in habitat use. Determining how morphological or behavioural traits can influence species adaptability to the built environment may enable us to improve the effectiveness of conservation efforts. The morphological similarities between P. pygmaeus and P. pipistrellus suggest that both species should respond similarly to the urban matrix, however I found differential habitat use occurring within a variety of urban habitats (e.g. woodland and waterways) and at a landscape scale. In urban woodland there was a higher probability of P. pygmaeus activity relative to P. pipistrellus in woodlands with low clutter and understory cover which were surrounded by low levels of built environment. Many bat species are strongly associated with aquatic or adjacent riparian habitats yet we know little about the utilisation of urban waterways by bats. After surveying urban waterways throughout the UK, I was able to show that the built environment can negatively affect a variety of bat species from the riparian zone up to 3km from a waterway. This indicates that beneficial urban waterway rehabilitation schemes for bats require management at multiple spatial scales, from retaining a vegetated riparian zone at the local scale to highlighting the necessity for conservation funding to be spent on the implementation of landscape scale environmental improvement schemes that encompass the entire urban matrix. Undertaking surveys to confirm species presence or to estimate population sizes can be difficult, particularly for elusive species such as bats. I was able to demonstrate a variety of ways to increase surveying efficiency (e.g. the use of an acoustic lure to increase bat-capture rate) and a significant relationship between bat activity and the relative abundance of certain species of bat which can maximise the knowledge of diversity in an area whilst minimising wildlife disturbances. Urbanisation has also had strong negative effects on many insect groups, such as moths, which are important components of the diets of many bat species. I found that woodland vegetation characteristics were more important than the surrounding landscapes in determining the abundance, species richness, and species diversity of moth assemblages within urban woodland. This indicates that management at a local scale to ensure provision of good quality habitat may be more beneficial for moth populations than improving habitat connectivity across the urban matrix. The findings presented in this thesis have important implications for our understanding of the adaptability of species to the built environment and for the management and monitoring of bat populations. It also highlights that even common bat species are negatively affected by urbanisation and much greater attention should be paid to securing their future within the urban landscape.
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Host Specificity and Ectoparasite Load of Bat Flies in Utila, Honduras

Miller, Courtney 01 August 2014 (has links)
Bat flies (Streblidae) are obligate blood-feeding ectoparasites of bats that display varying degrees of host specificity. A total of 265 streblid bat flies were collected from 122 bats belonging to the families Phyllostomidae and Natalidae from Utila, the smallest bay island of Honduras. Out of four host-parasite associations, three were considered primary. Out of the three bat species analyzed, one had significantly lower parasite prevalence and another had significantly higher parasite load and intensity. Both male and female bats were equally likely to be infested and variables of parasite density did not differ amongst host sex for any species. However, one species of bat had a significantly larger number of male parasites than female parasites. No significant relationships were found between variables of parasite density and host body mass or bat health (indicated by the ratio of mass to forearm length). The roosting ecology of the two cave roosting species in the study was considered and despite no apparent lack of dispersal barriers, the bat flies exhibited consistent primary associations. Examination of similar host-parasite relationship has many implications in parasite-host relationships and coevolution.
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O processo inflamatório, a resposta imune \"in situ\" e a morte neuronal em sistema nervoso central de pacientes com raiva transmitida por morcegos / Inflammatory process, in situ immune response and neuronal death in central nervous system of patients with rabies transmitted by bats

Fernandes, Elaine Raniero 17 June 2009 (has links)
A raiva é uma doença do sistema nervoso central que é quase invariavelmente fatal. Apesar de causar cerca de 60.000 mortes/ano, a raiva ainda permanece uma doença negligenciada na maioria dos países, principalmente naqueles em desenvolvimento. O objetivo do nosso estudo foi verificar nos microambientes meningeal, perivascular e intraparenquimatoso do sistema nervoso central, o processo inflamatório, a resposta imune do hospedeiro e a morte dos neurônios frente à infecção rábica transmitida por morcegos. Verificamos que a raiva humana transmitida por morcegos é uma meningoencefalomielite. Através de reação imuno-histoquímica caracterizamos e quantificamos in situ a distribuição do antígeno viral, o fenótipo de células inflamatórias, as células expressando citocinas pró inflamatórias, citocinas representativas de padrão Th1 e Th2 e células em apoptose. O antígeno viral foi encontrado difusamente no parênquima cerebral, em maior abundância em neurônios, não diferindo sua distribuição em relação as regiões cerebrais. As células da glia, em especial os astrócitos, estavam imunomarcadas com o antígeno da raiva, assim como as células endoteliais e células mononucleadas da luz vascular. Esses achados contribuíram para a hipótese da ocorrência de uma via hematogênica alternativa de disseminação viral, através da infecção de células endoteliais pelo vírus, posterior infecção de astrócitos e finalmente infecção de neurônios. A expressão significativa de IL-12 nos pacientes rábicos provavelmente traduz imunidade de base preservada. Identificamos, outrossim, falta de resposta efetiva das células NK e comprometimento da resposta imune adaptativa seqüencial, demonstrada pela depleção de linfócitos TCD4+ no parênquima cerebral, prejuízo da atividade citotóxica dos linfócitos TCD8+ com proporcionalmente baixa expressão de granzima e expressão rarefeita de IFN-g e IL-2r. Essa situação deve ser reflexo da manipulação do vírus sobre a resposta imune inata e adaptativa do hospedeiro tendo como conseqüência uma reposta ineficaz para clareamento do vírus. A expressão aumentada de citocinas pró-inflamatórias (IL-1b, IL-6 e TNF-a) contribuiu para o dano neuronal. O padrão citocínico predominante no sistema nervoso central na raiva foi o Th2, com alta expressão de IL-4 e IL-10. O TGF-b aumentado nos casos de raiva favorece um ambiente imunossupressor para manter intacta a rede neuronal, mas também contribui para permanência local do vírus. A verificação de grau pouco acentuado de neurônios apoptóticos em contraposição a apoptose expressiva de linfócitos TCD4+ e TCD8+, indicaria a utilização pelo vírus de mecanismos ora anti-apoptóticos para preservar neurônios e favorecer a disseminação viral, ora pró-apoptóticos, destruindo linfócitos e atenuando o processo inflamatório. Em síntese, o envolvimento do sistema nervoso central em decorrência da raiva se faz às custas de processo inflamatório com predomínio local de linfócitos TCD8+, um padrão Th2 de expressão de citocinas, acometendo os microambientes meningeal, perivascular e intraparenquimatoso, sendo o bulbo a região mais afetada pelo processo. / Viral disease of central nervous system almost invariable fatal, rabies causes about 60.000 deaths yearly, and still remain a neglected disease in most countries, specially in developing ones. We study the meningeal, perivascular and parenquimal environment in central nervous system from patients who dies after bat transmitted rabies, looking for the inflammatory process, host immune response and neuronal death. We show that human rabies transmitted by bats is a meningoencephalomyelitis. Immunohistochemistry allows the in situ quantification of viral antigen distribution, inflammatory cellular phenotype, expression of cytokines representing both Th1 and Th2 profile and pro-inflammatory and cell apoptosis. Viral antigen was found disseminatted in cerebral parenquima, more abundant in neurons, without cerebral area preference. Glial cells, specially astrocytes, were immunostained with rabies antigen, as well as endothelial and vascular mononuclear cells. These findings contributed for an alternative hypothesis of the occurrence of hematogenic viral dissemination, through viral infection or passage by endothelial cells, followed by astrocyte infection, and finally reaching neurons. IL-12 significant expression in central nervous system from rabies patients probably reflect preservation of immunity. The lack of effective NK cells could compromise adaptive immune response, demonstred by TCD4+ lymphocytes depletion in cerebral parenquima, ineffective TCD8+ cytotoxic activity with low granzyme expression and low expression of IFN-g and IL-2r. This situation reflects viral effect on host innate and adaptive immune response leading to an ineffective response for viral clearance. High pro-inflammatory cytokine expression, IL- 1b, IL-6 and TNF-a, contribute for neuronal damage, with predominant Th2 cytokine profile in central nervous system in rabies patients, with high expression of IL-4 and IL-10. Increased TGF-b expression also shows an immune suppressor environment, which maintains the neuronal network intact, but also contributes for viral permanence. The low degree of apoptotic neurons opposed with expressive apoptosis of TCD4+ and TCD8+ lymphocytes, could indicate viral mechanisms anti-apoptotic for neurons preservation and favour viral dissemination, or pro-apoptotic, destroying lymphocytes and attenuating the inflammatory process. In synthesis, the involvement of central nervous system in rabies is consequence of inflammatory process with TCD8+ lymphocytes predominance, Th2 profile cytokines expression, affecting all brain compartments and areas, especially the medulla oblongata.

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