The chromosome passenger complex (CPC) is an essential mitotic regulator with key roles in mitotic processes such as chromosome condensation, spindle dynamics, chromosome bi-orientation, the spindle checkpoint and cytokinesis. The Aurora B kinase is the CPC’s catalytic subunit. Its targeting and activation are dependent on interactions with the other components of the complex: inner centromere protein (INCENP), survivin and borealin/Dasra B. INCENP serves both as a scaffolding subunit for the CPC as a whole and as an activator of Aurora B via its highly conserved INbox domain. Aurora B is a putative anti‐cancer target; several inhibitors of the kinase are currently in clinical trials. All these are ATP-analogues targeting the kinase active site. The protein-­protein interaction between Aurora B and the INCENP INbox is also essential for CPC function. Earlier studies have demonstrated that INCENP INbox mutants unable to bind and/or activate Aurora B cannot rescue lethality in the absence of endogenous INCENP. The first goal of this study was to test the in vivo effects of disrupting the interaction between endogenous wild type INCENP and Aurora B. For this, a cell-based CPC function assay was developed in HeLa cells. Using this assay, I show that expression of soluble INbox in HeLa cells produces a significant increase in multinucleated and micronucleated cells: both effects consistent with Aurora B loss of function. Expression of soluble INbox bearing the mutations W845G and/or F881A does not elicit this effect suggesting that those mutants cannot bind to Aurora B and occlude INCENP binding. The result concerning the F881A mutant contrasts with earlier reports that equivalent mutants could bind, but not activate, Aurora B. Expression of an INbox mutant lacking the C-­terminal TSS motif reported to be involved in Aurora B activation but not binding has effects similar to those of the wild type INbox. Using the INbox/Aurora B interaction as a model, a secondary goal of this study was to develop and evaluate a novel approach to identify small peptides capable of dissociating intracellular protein‐protein interactions. For this, a library of small (5-­9 residues long) circular peptides (CPs) mimicking the INbox was generated using the split intein circular ligation of proteins and peptides (SICLOPPS) methodology and assayed using the cell-­based CPC function assay. Over two successive rounds of screening, a small number of CPs were identified that caused a significant increase in rates of multinucleated and micronucleated cells. Although statistically significant, these increases were very modest. Furthermore, due to high heterogeneity in SICLOPPS processing efficiencies, it was not practicable to compare the effects of different peptides side-­by-side by transfection. The level of variation in processing efficiency – thus, CP production – was unexpectedly high and puts into question the functional complexity of more commonly used combinatorial cyclic peptide libraries derived using current SICLOPPS methodology. The results of this study are divided into three sections. The first is a methods section concerning the testing of SICLOPPS in HeLa cells and the development of a cell­‐based CPC function assay. In the second, the effects of expressing soluble INbox and mutants thereof in HeLa cells are presented. The final results section presents the results of the feasibility study of the rationally-­designed genetically encoded library approach.

Genomes usually work together to promote the fitness of the organism, but sometimes parts of the genome cause intragenomic conflict, and act selfishly in order to promote their transmission. An example of this conflict is a selfish B chromosome known as paternal sex ratio (PSR) in the jewel wasp Nasonia vitripennis. Transmitted solely to new progeny with the sperms hereditary material, PSR completely destroys the paternal genome during the first mitotic division of the newly fertilized embryo. This effect enhances transmission of the PSR chromosome because of the unique haplodiploid reproductive mode of Nasonia and other members of the hymenopteran insect group. Through transcriptomic analyses, our group recently discovered that the PSR chromosome expresses eleven transcripts in the wasp testis. A plausible hypothesis is that one or more of these transcripts play some role in paternal genome elimination. In this study I have begun to test this hypothesis by screening through a set of previously produced truncated versions of the PSR chromosome. Specifically, I used PCR in order to screen these truncated chromosomes for the presence of each of these PSR-specific transcripts. I could then correlate the level of genome elimination induced by each truncated PSR chromosome with the presence or absence of the expressed transcripts. My work has established that (i) three of the eleven transcripts are likely not involved in genome elimination; (ii) no single transcript alone causes genome elimination; (iii) the remaining eight of eleven transcripts are viable candidates for causing genome elimination; and (iv) it is likely that a sub-group of these transcripts may operate together to induce this effect. I discuss several models in which PSR-expressed RNA molecules could operate to cause genome elimination.

Orientador: Cesar Martins / Resumo: B chromosomes (Bs) are additional to the standard regular chromosome set (As), and present in all groups of eukaryotes. A reference genome is key to understand genomics aspects of an organism. Here, we present the de novo genome assembly of the cichlid fish A. latifasciata: a well known model to study Bs. The assembly of A. latifasciata genome has not been performed so far. The main focus of this study is to analyze and assemble the A. latifasciata genome with no B (B-) and with B (B+) chromosomes. The assembled draft B- and B+ genomes comprised of 774 Mb and 781 Mb with 1.8 Mb and 2.5Mb of N50 value of scaffolds respectively, and spanning 23,391 number of genes. High coverage data with Illumina sequencing was obtained for males and females with 0B, 1B and 2B chromosomes to provide information regarding the population polymorphism of these genomes. We observed a high scale genomic diversity in all analyzed genomes showing a high rate/frequency of population polymorphism with no evident effect of B chromosome presence. However, the B specific single nucleotide polymorphisms were found in the sequences that were located on B chromosome. While, the whole-genome rearrangements (inter chromosomal translocations) were detected in B+ genome, and structural variations including insertions, deletions, inversions and duplications were predicted in a representative genomic region of B chromosome. These results bring an evidence that existence of Bs in a genome should favour the accumu... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Submitted by (ana.araujo@ufrpe.br) on 2017-02-22T14:59:44Z No. of bitstreams: 1 Winston Jose Pessoa Felix.pdf: 3066003 bytes, checksum: e332581b7efc29ec2ebf2e0c4af9c437 (MD5) / Made available in DSpace on 2017-02-22T14:59:44Z (GMT). No. of bitstreams: 1 Winston Jose Pessoa Felix.pdf: 3066003 bytes, checksum: e332581b7efc29ec2ebf2e0c4af9c437 (MD5) Previous issue date: 2009-06-29 / The cytogenetic characteristics and CMA / DAPI band patterns in seven species of Zephyranthes and a Habranthus were studied in this paper to evaluate the karyotypic differences between these species. All individuals presented reticulated or semi-reticulated interphased nuclei and karyotype formed by a set of metacentric chromosomes, in addition to submetacentric and acrocentric chromosomes. Zephyranthes robusta, with 2n = 12 and karyotypic formula 4M +2 SM presented more symmetrical karyotype. Z. sylvatica showed chromosome complement composed of 2n = 12 being 1M+5SM, 2n = 13 being 1M+5SM + (B) SM and 2n = 18 formed by cracks, one with metacentric and five with only submetacentric (1M+5SM). For the cultivated species Zephyranthes rosea Lindl. presented karyotype with 2n = 24 and karyotypic formula 4M+7SM +1A. Zephyranthes grandiflora Lindl. presented the same chromosome count of the previous species, being observed 2M +5 SM +5 A. Zephyranthes aff. rosea Lindl. presented 2n = 25, being 3M + (1M "crack") +7 SM +1 A. Furthermore, it was observed the presence of trisomy in fourth metacentric pair. Zephyranthes brachyandra Herb. presented karyotype with 2n = 24 +1 B and formula 4M +3 SM +5 A +1 B. In Zephyranthes candida Herb. 2n = 38 was observed with 9M +5 SM +5 A. For H. itaobinus Ravenna, a numeric variation in the counts was observed, where in most populations the additional chromosomes were formed by 2n = 45 or 5M +12 SM +5 A + (B) M and in a single population the species showed presented karyotype with 2n = 44, 6M +12 SM +5 A +3 (B)M. Interstitial and subterminal DAPI bands were observed only in Z. robusta and Z. brachyandra. The remaining species showed no AT-rich heterochromatin. In species with 2n = 12 was found a CMA+ block in a chromosome pair of Z. robust and Zephyranthes sp., while in Z. sylvatica was observed a small additional terminal block. Z. rosea and Z. grandiflora had four CMA+ bands, while there were eight interstitial pinpoint bands, apart from the heterochromatic RON and a bigger block in the terminal of the short arm of B chromosome in Z. brachyandra. In Z. candida, there were 14 subterminal CMA bands and in H. itaobinus, seven bands with strong differentiated amplification in the heterochromatic RON. Taxonomic implications and the karyotypic evolution are discussed for the species studied. / No presente trabalho foram estudados a caracterização citogenética e os padrões de banda CMA/DAPI em sete espécies de Zephyranthes e uma de Habranthus com o objetivo de avaliar as diferenças cariotípicas entre essas espécies. Todos os indivíduos apresentaram núcleo interfásico reticulado ou semi-reticulado e cariótipo formado por um conjunto de cromossomos metacêntricos, além de cromossomos submetacêntricos e acrocêntricos. Zephyranthes robusta, com 2n=12 e fórmula cariotípica 4M+2SM, apresentou cariótipo mais simétrico. Z. sylvatica apresentou complemento cromossômico formado por 2n=12 sendo 1M+5SM, 2n=13 sendo 1M+5SM+(B)SM e 2n=18 formadas por trincas, uma com metacêntricos e cinco apenas com submetacêntricos (1M+5SM). Para as espécies cultivadas, Zephyranthes rosea Lindl. Apresentou cariótipo com 2n=24 e fórmula cariotípica 4M+7SM+1A. Zephyranthes grandiflora Lindl. apresentou a mesma contagem cromossômica da espécie anterior, sendo que foram observados 2M+5SM+5A. Zephyranthes aff. rosea Lindl., apresentou 2n=25, sendo 3M+(1M“trinca”) +7SM+1A. Além disso, pôde-se observar a presença de trissomia no par quatro metacêntrico. Zephyranthes brachyandra Herb. apresentou cariótipo com 2n=24+1B e fórmula 4M+3SM+5A+1B. Para Zephyranthes candida Herb. observou-se 2n=38, sendo 9M+5SM+5A. Em H. itaobinus Ravena observou-se variação numérica nas contagens onde na maioria das populações os complementos cromossômicos foram formados por 2n=45 ou 5M+12SM+5A+(B)M e em uma única população a espécie apresentou cariótipo com 2n=44, 6M+12SM+5A+3(B)M. Foram observadas bandas DAPI subterminais e intersticiais apenas em Z. robusta e em Z. brachyandra. As demais espécies não apresentaram heterocromatina rica em AT. Nas espécies com 2n=12 foi observado um bloco CMA+ em um par cromossômico de Z. robusta e Zephyranthes sp., enquanto em Z. sylvatica foi observado um pequeno bloco terminal adicional. Z. rosea e Z. grandiflora, tiveram quatro bandas CMA+, enquanto em Z. brachyandra, ocorreram oito bandas intersticiais puntiformes, além da RON heterocromática e de um bloco maior no terminal do braço curto do cromossomo B. Em Z. candida, observouse 14 bandas CMA subterminais e em H. itaobinus, sete bandas, com forte amplificação diferenciada na RON heterocromática. São discutidas as implicações taxonômicas e a evolução cariotípica para as espécies estudadas.

Made available in DSpace on 2015-03-26T13:42:07Z (GMT). No. of bitstreams: 1 texto completo.pdf: 370964 bytes, checksum: 4fbb1985432d879bf053fe1416468899 (MD5) Previous issue date: 2008-10-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / B chromosomes, called supernumerary or accessory too, has been founded in fungi, plants and animals. This chromosomes have a rate of no mendelian segregation and he can occurs, since one to many copies by individual. In the gender Partamona, of six citogenetic characterazed species nowadays, only P. helleri owned B chromosome. RAPD mark has been identified as associated to this chromosome in a colony from Viçosa City-MG. After this, it has been cloned, sequenciated and transformated in a SCAR mark. This same mark has been identified in P. cupira, P. criptica and P. rustica, what suggested this species have B chromosome, too. Moreover, this same mark has been identified in a colony of Salvador City-BA. whose individuals have a big heterochromatic B chromosome. How it's possible that there is a association between the presence of B chromosomes, this work had as aim detect the presence of B chromosome in P. cupira and verified a possible association between them and the presence of SCAR mark described above. Another object was the sequenciation of SCAR fragment from P. cupira, P. criptica, P. rustica and P. helleri (Salvador City-BA), with the aim of comparer the level of identity between the SCAR sequences. As resulted, the four colony at all from P. cupira analised, only two ownied the chromosomic number 2n=34, otherwise the other two colonies ownied same individuals that demonstrated have the presence of a great B chromosome (GUI 1 E GUI 11). Another observation was CMA3 mark in the short arm of this supernumerary chromosomes, what suggest that them may have owned ribossomal DNA sequeces. Moreover, it has been verified a clear association between the presence of SCAR mark and B chromosomes in the individuals from colonies GUI 1 E GUI 11. It's considered that sequences compared at all, have been only same gaps and almost none variable site, between them, what suggests that the level of identity between sequences is extremely high. It's suggests some kind of importance in relation to the adaptation of chromosome B, nowadays unknown, or the born of B, throw interspecific mating no detected yet. Future studies will analyze the different hypothesis about the origin of B chromosomes in the genera Partamona and the association between fragments from SCAR primers with the presence of Bs in P. criptica, P. rustica e P. helleri (Salvador City-BA). / Cromossomos B, também chamados de cromossomos extra- numerários ou acessórios ocorrem em fungos, plantas e animais. Estes cromossomos possuem um padrão de segregação não mendeliano, podendo existir de uma a várias cópias por indivíduo. No gênero Partamona, de seis espécies caracterizadas citogeneticamente até então, somente P. helleri apresentou cromossomo B. Um marcador RAPD foi identificado como associado a esse cromossomo em uma colônia oriunda de Viçosa-MG, sendo posteriormente clonado, sequenciado e transformado em marcador SCAR. Este mesmo marcador foi identificado em P. cupira, P. criptica e P. rustica, o que sugere que estas espécies também possuem cromossomos B. Além disso, esse mesmo marcador foi detectado em indivíduos de um ninho de P. helleri de Salvador - BA, cujos indivíduos possuíam um grande cromossomo B heterocromático. Podendo haver uma ligação entre a presença do marcador SCAR nestas espécies e a presença de cromossomos Bs, este trabalho teve como objetivo detectar a presença de cromossomos B em P. cupira e verificar se existe uma associação entre ele e a presença do marcador SCAR descrito acima. Um outro objetivo foi o sequenciamento dos fragmentos SCARs de P. cupira, P. criptica, P. rustica e P. helleri de Salvador-BA, com o propósito de comparar o nível de identidade entre as sequencias de SCAR. Como resultado, das 4 colônias de P. cupira analisadas, duas apresentaram o número de 2n=34, ao passo que as outras duas apresentaram em alguns indivíduos um cromossomo B de grande tamanho (colônias GUI 1 e GUI 11). Observou-se ainda, uma marcação de CMA3 no braço curto destes cromossomos extranumerários, o que sugere que o mesmo pode conter sequencias de genes de DNA ribossomal nesta espécie. Verificou-se também uma clara associação entre a presença do marcador SCAR e a de cromossomos B, nos indivíduos das colônias GUI 1 e GUI 11. Levando em conta que as sequências, comparadas em conjunto possuíam apenas alguns gaps e quase nenhum sítio variável entre elas, pode-se dizer que o nível de identidade entre elas é extremamente alto, o que sugere algum tipo importância adaptativa em relação ao cromossomo B, ainda desconhecida, ou o surgimento deste último, através de cruzamentos interespecíficos, ainda não detectados entre as espécies do gênero. Estudos futuros deverão analisar as diferentes hipóteses levantadas sobre a origem dos cromossomos B no gênero Partamona, bem como a associação dos fragmentos oriundos dos primers SCAR de P. helleri com a presença destes cromossomos em P. criptica, P. rustica e P. helleri de Salvador BA.

Orientador: Fausto Foresti / Resumo: Characidium é um grupo de peixes amplamente distribuídos pela região Neotropical, embora seja considerado o mais especioso dentro de Crenuchidae, do ponto de vista citogenético o número de espécies investigadas ainda é baixo, o que dificulta a caracterização quanto a organização cromossômica do gênero. Em relação ao número diploide, as espécies de Characidium conservaram um cariótipo com 2n = 50 cromossomos, do tipo metacêntricos e submetacêntricos (com exceções), o que resulta em uma macroestrutura homogênea para o grupo. Porém, investigações utilizando sequências repetitivas têm contribuído para ilustrar que a organização microestrutural cromossômica pode diferir entre as espécies, refletindo o hábito destes peixes constituírem populações pequenas e isoladas em cabeceiras de riachos. Adicionalmente, algumas espécies de Characidium também foram descritas portando cromossomos B em seus cariótipos, e a utilização de ferramentas citomoleculares têm contribuído para explorar quanto a origem e evolução destes componentes cariotípicos. Neste sentido, o objetivo do presente estudo foi agregar técnicas citomoleculares com resultados de sequenciamento massivo, para tentar compreender a ocorrência de cromossomos B no genoma de Characidium sp. aff. C. vidali. Os resultados obtidos mostraram que i) o mapeamento físico de diferentes sondas de DNA repetitivo contribuíram não apenas para caracterizar o cariótipo da espécie em estudo, como também adicionaram mais informações quanto a organi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Characidium is a group of fish widely distributed in the Neotropical region, although it is considered the most specious within Crenuchidae, from the cytogenetic point of view the number of species investigated is still low, which makes it difficult to characterize the chromosomal organization of the genus. In relation to the diploid number, Characidium species retained a karyotype with 2n = 50 chromosomes, metacentric and submetacentric (with exceptions), resulting in a homogeneous macrostructure for the group. However, investigations using repetitive sequences have contributed to illustrate that the chromosomal microstructural organization may differ between species, reflecting the habit of these fish constituting small and isolated populations in headwaters of streams. In addition, some species of Characidium have also been described carrying B chromosomes in their karyotypes, and the use of cyto-molecular tools has contributed to explore the origin and evolution of these karyotype components. In this sense, the objective of the present study was to aggregate cyto-molecular techniques with massive sequencing results to try to understand the occurrence of B chromosomes in the genome of Characidium sp. aff. C. vidali. The results showed that i) the physical mapping of different repetitive DNA probes contributed not only to characterize the karyotype of the species under study, but also added more information about the organization and evolution of the chromosomal microstruct... (Complete abstract click electronic access below) / Doutor

Submitted by Natalia de Souza Gonçalves (natalia.goncalves@ufpe.br) on 2016-09-23T13:21:33Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Diversidade cromossômica e molecular de gafanhotos neotropicais_Tese_Tyago Eufrásio de Souza_2016.pdf: 5140522 bytes, checksum: a3f59c2f3fae3b977e8e585c0f3ff493 (MD5) / Made available in DSpace on 2016-09-23T13:21:33Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Diversidade cromossômica e molecular de gafanhotos neotropicais_Tese_Tyago Eufrásio de Souza_2016.pdf: 5140522 bytes, checksum: a3f59c2f3fae3b977e8e585c0f3ff493 (MD5) Previous issue date: 2016-03-03 / CAPES / Nos últimos anos, alguns estudos de mapeamento cromossômico foram realizados em gafanhotos do grupo Acridomorpha, preferencialmente através do uso de sondas de sequências repetitivas. Este trabalho tem como objetivo contribuir para uma melhor compreensão dos aspectos cromossômicos evolutivos em gafanhotos acridomorfos e da diversidade genética de Ommexecha virens. Os genes de cópia única Hsp83, Hsp70, Hsp27, Ubi, Lys foram localizados nos cromossomos meióticos de Ommexecha virens, Xyleus discoideus angulatus, Tropidacris collaris e Stiphra robusta e Lys em Schistocerca pallens através de Hibridização in situ permanente (PISH). Sequências repetitivas de rDNA 45S, rDNA 5S e Histona H3 foram localizadas em O virens através de Hibridização in situ fluorescente (FISH). Em O. virens também foi analisado o cromossomo B por técnicas convencionais, diferenciais e moleculares, bem como a estrutura genética de oito populações naturais (seis de Pernambuco, uma da Bahia e uma do Ceará) do Nordeste brasileiro com o marcador ISSR (regiões entre sequências de repetições simples). Os genes de cópia única apresentaram um padrão conservado de localização em pares cromossômicos grandes, preferencialmente o L1, exceto para Hsp70 e Ubi, localizados no L2. Sinais secundários foram observados em cromossomos médios. A conservação apresentada deve-se a ausência ou pequena ocorrência de rearranjos nos cromossomos destes cariótipos, o que reduz o risco de eventos deletérios, bem como pela localização coincidente com regiões ricas em heterocromatina constitutiva. A conservação da localização destes genes indicou os cromossomos portadores dos locus gênicos ancestrais para os genes mapeados. O estudo do cromossomo B em O. virens revelou similaridade de tamanho e marcação CMA3 positiva com o cromossomo 9, sugerindo a possível origem deste cromossomo. Contudo, a presença de sítios de rDNA 45S e Histona H3 no cromossomo 9 e ausência no B, provavelmente pela deleção dessas sequências neste cromossomo, não permitem descartar a possibilidade do B ter se originado de outro cromossomo. A análise genética populacional em O. virens mostrou três cluster, os quais exibiram relação com aspectos da biologia da espécie, a paisagem dos ambientes amostrados e com as modificações geológicas ocorridas no Nordeste brasileiro, em particular a formação do complexo da Borborema e a Chapada do Araripe. / In recent years, some chromosomal mapping studies were performed in Acridomorpha group grasshoppers, preferably through the use of repetitive sequence probes. In this work in order to contribute to a better understanding of evolutionary chromosomal aspects of acridomorphs and genetic diversity of Ommexecha virens. The single copy genes Hsp83, Hsp70, Hsp27, Ubi, Lys were located in meiotic chromosomes of Ommexecha virens, Xyleus discoideus angulatus, Tropidacris collaris and Stiphra robusta, and Lys in Schistocerca pallens through permanent situ hybridization (PISH). Repetitive sequences of 45S rDNA, 5S rDNA and H3 histone were located in the O. virens via fluorescent in situ hybridization (FISH). In O. virens was also analyzed the B chromosome by conventional, differential and molecular techniques and genetic structure of eight natural populations (six of Pernambuco, one of Bahia and one of Ceará) of the Northeast of Brazil with ISSR marker (inter simple sequence repeat). Single copy genes showed a conserved pattern of location in large chromosomal pairs, preferably L1, except for Hsp70 and Ubi, located in L2. Secondary signals were observed on medium chromosomes. The presented conservation due to absence or occurrence of small rearrangements in these karyotypes, which reduces the risk of deleterious events as well as for matching location with regions rich in heterochromatin. The conservation of the location of these genes indicated the chromosomes carrying the genic locus ancestors to the mapped genes. The study of B chromosome of O. virens revealed similarity in size and CMA3 positive marking to chromosome 9, suggesting the possible origin of this chromosome. However, the presence of 45S rDNA sites and H3 histone on chromosome 9 and the absence on B, probably due to deletion of these sequences in this chromosome, do not allow to rule out the possibility of B have originated from another chromosome. Population genetic analysis O. virens showed three clusters, which exhibited relationship with aspects of the biology of the species, the landscape of the study sites and the geological changes occurred in northeastern of Brazil, in particular the formation of the Borborema and Araripe plateaus.

Les habitats sur le substrat de serpentine représentent un environnement hostile pour le développement des plantes. Ils sont caractérisés par un faible nombre d’espèces mais un haut niveau d’endémisme. Cette étude présente pour la première fois une série des données sur la taille du génome, du nombre chromosomique, du niveau de ploïdie, de l’affinité pour le substrat, du cycle de vie, du type et de la forme de croissance des serpentinophytes dans l’extrême nord-ouest de la zone de serpentine dans les Balkans. Les 308 taxons des plantes étudiées comprennent appartenant à 213 genres, dont la taille du génome est donnée pour la première fois pour 28 genres et 99 espèces. En utilisant les critères de Leitch, plus de la moitié des taxons (55.63%) appartiennent au groupe des très petits génomes, 22.19% aux petits, 18.75% aux moyens, 3.13% aux grands, et seulement 0.31% aux très grands génomes. Concernant l'affinité au substrat, la majorité d’espèces (171) sont indifférentes ou des serpentinophytes facultatives (103). Selon le type de cycle de vie, ~ 4% des espèces sont annuelles, 88.31% pérennes, dont 57% possèdent de très petits génomes. Les hémicryptophytes représentent une forme de vie dominante (48.38%), tandis que les phanérophytes représentent 17%, les chaméphytes 15%, les thérophyte 9% et les géophytes 9%. Il est évident que le stress hydrique, les températures élevées et la présence de métaux lourds dans les habitats sur la serpentine jouent une haute pression sélective et favorisent des espèces pérennes à très petits génomes.Le Narcissus poeticus (Amaryllidaceae), serpentinophyte facultative, est l’ancêtre des narcisses cultivés. C'est la première étude de N. poeticus et de sa rhizosphère dans les populations naturelles. Il montre une tolérance au pH du sol qui varie du 4.64 à 7.85. Les concentrations totales de nickel, de cobalt et de magnésium sont plus élevées dans les sols sur serpentine que dans ceux sur calcaires. Narcissus poeticus est caractérisé par une plus grande accumulation de manganèse, de nickel et de magnésium dans ses parties aériennes. Le cobalt, par contre, a une concentration totale uniforme dans toutes les parties de la plante. Une autre caractéristique inhabituelle de N. poeticus est son plus grand rapport molaire Ca/Mg dans les parties souterraines, probablement dû à sa forme de vie (géophytes) et une dormance estivale. Il est évident que, même si N. poeticus accumule certaines quantités de métaux lourds estimés (Mn, Ni, Co, Fe), il n'est pas pour autant un hyperaccumulateur.Une partie importante de ce travail concerne la variabilité de la structure chromosomique, la taille du génome, le niveau de ploïdie et la présence de chromosomes B dans 13 populations naturelles de N. poeticus poussant sur différents substrats géologiques et dans différentes conditions environnementales. La technique de la cytométrie en flux a été utilisée pour estimer la taille du génome, l’hybridation in situ fluorescente (FISH) pour la cartographie physique de l'ADNr, le fluorochrome banding pour l'organisation de l’hétérochromatine et la coloration au nitrate d’argent pour estimer l'activité des gènes ribosomiques. L’organisation des gènes ribosomiques et l’existence des triploïdes naturels ont été rapportés ici pour la première fois. Présence des individus portant de chromosomes B (dans 9 populations sur 13) et de translocations chromosomiques a été détectée. Un système particulier de chromosomes B présente trois différents morphotypes. Le submétacentrique type, le plus fréquent, possède quatre paternes différents dans l’organisation de l’hétérochromatine et de l'ADNr. La coloration à l’AgNO3 a montré que le nombre de nucléoles formés augmente en présence des chromosomes B portant des gènes ribosomiques, dont l’activité est ainsi prouvée. Les résultats obtenus démontrent que N. poeticus possède un génome dynamique avec la quantité d’ADN variable en raison de la présence de polyploïdie, de chromosomes B et de réarrangements chromosomiques. Il semble que les modifications observées reflètent la réponse du génome à différentes conditions environnementales où les individus portant les chromosomes B pourraient avoir des avantages sélectifs. / Habitats on serpentine substrate present a hostile environment for the plants development. They are characterized by a small number of species, but high levels of endemism. This study shows for the first time a series of data on genome size, chromosome number, ploidy level, the affinity to the substrate, the life cycle, the type and form of growth in the extreme northwest region of serpentine area in the Balkans. The sample includes 308 taxa belonging to 213 genera, with new values recorded for 28 genera and 99 species. Using Leitch’s criteria, more than half of estimated taxa (55.63%) belong to the group of very small genomes, 22.19% small, 18.75% intermediary, 3.13% large and only 0.31% to very large genomes. Regarding the affinity to the substrate, the majority of species (171) were indifferent or facultative serpentinophytes (103). Concerning the life cycle, ~ 4% of species are annuals and 88.31% perennials, and 57% had very small genomes. Hemicryptophytes represent a dominant life form (48.38%), phanerophytes 17%, 1chamaephytes5%, therophytes 9% and geophytes 9%. It is clear that the water stress, high temperatures and presence of heavy metals in serpentine habitats have the high selective pressure and favor perennial species with very small genome.The Narcissus poeticus (Amaryllidaceae), facultative serpentinophyte, is the ancestor of cultivated daffodils. This is the first study of N. poeticus and its rhizosphere in natural populations. It shows tolerance to soil pH ranging from 4.64 to 7.85. Serpentine soils have total concentrations of nickel, cobalt and magnesium highest, compared with calcareous soils. Narcissus poeticus is characterized by the greater accumulation of manganese, nickel and magnesium in the aerial parts of plant. Against the cobalt has a uniform total concentration in all parts of the plant. Another unusual feature of N. poeticus is the highest molar ratio Ca / Mg in the underground parts, probably du to his life form (geophytes) and summer dormancy. It is obvious that although N. poeticus accumulate certain amounts of estimated heavy metals (Mn, Ni, Co, Fe), it does not a hyperaccumulator.An important part of this work concerns the variability of the chromosome structure, genome size, the ploidy level and the presence of B chromosomes in 13 natural populations growing on different soils and under different environmental conditions. The technique of flow cytometry was used to estimate the genome size, fluorescent in situ hybridization (FISH) for the physical mapping of rDNA, the fluorochrome banding for the organization of heterochromatin and silver staining to estimate the activity of ribosomal genes. Organization of ribosomal genes and natural triploids have been reported here for the first time. Presence of individuals carrying B chromosomes (in 9 / 13 populations) and chromosomal translocations were detected. A particular system of B chromosomes presents three different morphotypes. The most common submetacentric type shows four different patterns in the organization of heterochromatin and rDNA. The AgNO3 staining showed that the number of nucleoli formed increases in the presence of B chromosomes carrying ribosomal genes, which proved their activity. The obtained results show that N. poeticus has a dynamic genome with the variable amount of DNA due to the presence of polyploidy, B chromosomes and chromosomal rearrangements. It seems that the observed changes reflect the response of the genome to different environmental conditions in which individuals carrying B chromosomes may have some selective advantages / Habitati na serpentinskim substratima predstavljaju nepovoljne uvjete za razvoj biljaka. Karakteriziraju se sa malim brojem vrsta, ali prisustvom velikog broja endema. U ovoj studiji se po prvi put prezentira serija podataka o veličini genoma serpentinofita, njihovom hromosomskom broju, nivou ploidije, sklonosti ka supstratu, tipu životnog ciklusa i životne forme na krajnjem sjeverozapadnom dijelu serpentinskog područja Balkanskog poluostrva. Uzorak je obuhvatao 308 svojti iz 213 rodova, sa novim vrijednostima za 28 rodova i 99 vrsta. Prema Leitch-evim kriterijima, više od polovine analiziranih svojti (55.63%) pripadale su grupi vrlo malih genoma, 22.19% malim, 18.75% srednjim, 3.13% velikim i samo 0.31% vrlo velikim genomima. U odnosu na sklonost ka supstratu, glavnina vrsta (171) su bile indiferentne ili fakultativne serpentinofite (103). U zavisnosti od životnog ciklusa, ~ 4% vrsta su bile jednogodišnje, a 88.31% višegodišnje, od kojih je 57% imalo vrlo male genome. Hemikriptofite su predstavljale dominantnu životnu formu (48.38%), koju slijede fanerofite (17%), hamefite (15%), terofite (9%) i geofite (9%). Iz dobivenih rezultata proizilazi da vodni stres, visoke temperature i prisustvo teških metala u serpentinskim habitatima imaju visok selektivni pritisak i favoriziraju višegodišnje vrste sa vrlo malim genomom.Narcissus poeticus (Amaryllidaceae), fakultativna serpentinofita, je predak kultiviranih narcisa. Ovo je prva studija o N. poeticus i njegovoj rizosferi u prirodnim populacijama. Ova vrsta pokazuje toleranciju na promjene pH vrijednosti u dijapazonu od 4.64 do 7.85. Totalne koncentracije nikla, kobalta i magnezija u serpenitnskim tlima su bile veće nego u krečnjačkim. Narcissus poeticus se karakterizirao većom akumulacijom mangana, nikla i magnezija u nadzemnim dijelovima biljke. Suprotno, kobalt je imao skoro istu totalnu koncentraciju u svim dijelovima biljke. Druga neuobičajena karakteristika N. poeticus je najveći iskazani molarni odnos Ca/Mg u podzemnim dijelovima, vjerovatno zbog njegove životne forme (geofita) i ljetne dormancije. Očito je da iako N. poeticus akumulira određene količine istraživanih teških metala (Mn, Ni, Co, Fe) on se ne moze smatrati nije njihovim hiperakumulatorom.Važan dio ove studije se odnosi na varijabilnost hromosomske strukture, veličine genoma, nivoa ploidije i prisustva B-hromosoma u 13 prirodnih populacija N. poeticus koje rastu na različitim geološkim supstratima i pod različitim okolišnim uslovima. Korištena je tehnika protočne citometrije za određivanje veličine genoma, fluorescentna in situ hibridizacija (FISH) za fizicko mapiranje rDNK, fluorohrom banding za organizaciju heterohromatina i bojenje srebrenim nitratom za utvrđivanje aktivnosti ribozomalnih gena. Organizacija ribosomalnih gena i prisustvo prirodnih triploida su u ovoj studiji saopćeni po prvi put. Uočeno je prisustvo individua koje nose B-hromosome (u 9 od 13 populacija) i hromosomske translokacije. Poseban sistem B-hromosoma je predstavljen sa tri različita morfotipa. Najčešći submetacentrični tip pokazuje četiri različita obrasca u organizaciji heterohromatina i rDNK. Bojenje s AgNO3 je pokazalo da se formirani broj nukleolusa povećava u prisustvu B-hromosoma koji nose ribosomalne gene, što potvrđuje njihovu aktivnost. Dobiveni rezultati pokazuju da N. poeticus ima dinamičan genom sa različitom količinom DNK usljed prisustva poliploidije, B-hromosoma i hromosomskih rearanžmana. Uočene promjene najvjerovatnije odražavaju odgovor genoma na različite okolišne uslove u kojima individue koje posjeduju B-hromosome imaju izvjesnu selektivnu prednost.