Unbranched heterocytous cyanobacteria exhibit complex filament and colony architectures and variable life strategies from symbionts to free living planktic and non-planktic species. They are counted among microbial groups showing an extensive production of secondary metabolites, resulting in both pharmaceutically important and toxic compounds. The main focus of this thesis is to broaden our knowledge on bioactive secondary metabolite potential in this widespread group of cyanobacteria. An effective combination of methods including whole genome sequencing, bioinformatic analysis, and analytical chemistry techniques are applied to accomplish this task. The discrepancies in distribution of various classes of compounds among ecological groups defined by different life strategies are discussed. Additionally, the thesis endeavours to test multidisciplinary approaches to tackle taxonomic assignments of unresolved unbranched heterocytous cyanobacteria using morphological, phylogenetic and ecophysiological methods, including a meta-analysis of morphological traits.

Morphology and ultrastructure of 25 oscillatorian strains was examined and phylogenetic analysis of 16S rDNA oscillatorian sequences was conducted. Genera Phormidium and Oscillatoria were shown to be polyphyletic. Although morphologically similar strains are found in different branches of the phylogenetic tree, considerable correlation between molecular, ultrastructural and some morphological and ecological traits was detected in several lineages.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-22T12:38:56Z No. of bitstreams: 1 Mariote dos Santos Brito Netto.pdf: 2798345 bytes, checksum: 06d5992ae421bc76a692bd417a393470 (MD5) / Made available in DSpace on 2017-03-22T12:38:56Z (GMT). No. of bitstreams: 1 Mariote dos Santos Brito Netto.pdf: 2798345 bytes, checksum: 06d5992ae421bc76a692bd417a393470 (MD5) Previous issue date: 2012-07-31 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The identity of Lasiodiplodia species in causing stem-end rot papaya is reveal. In the current study the Lasiodiplodia species isolated from papaya in Northeastern Brazil are described, as well as their distribution in seven different populations. Lasiodiplodia isolates are characterized through cultural, morphological, patogenicity and virulence data, and from phylogenetic analyses based on the complete sequence of the ITS region and partial sequence of the translation elongation factor-1α gene. Based on sequence data, three previously described species were identified (Lasiodiplodia theobromae, L. pseudotheobromae, L. hormozganensis) together with one unknown species. L. theobromae was the most prevalent species in all populations. All Lasiodiplodia species were pathogenic. / A identidade das espécies de Lasiodiplodia causando podridão peduncular em mamão é revelada. No presente estudo espécies de Lasiodiplodia isoladas de mamão no Nordeste do Brasil são descritas, bem como, a sua distribuição em sete diferentes populações. Os isolados de Lasiodiplodia foram caracterizados por inferência filogenética baseada na sequência completa da região ITS e na sequencia parcial do gene fator de alongamento, pelas características culturais e morfológicas, bem como pela patogenicidade e virulência. Três espécies previamente descritas foram identificadas (L. theobromae, L. pseudotheobromae, L. hormozganensis) juntamente com uma espécie desconhecida. Lasiodiplodia theobromae foi a espécie mais prevalente em todas as populações. Todas as espécies de Lasiodiplodia foram patogênicas.

The modern taxonomic revision of cyanobacteria is a work in progress, with both theoretical and practical challenges to be addressed. This thesis investigated selected terrestrial cyanobacterial taxa using a polyphasic approach, based on molecular phylogenetic analysis and accompanied by phenotypic characterization and nomenclatural treatment. Diverse methodological approaches were used including optical and transmission electron microscopy, molecular analysis (DNA sequencing) of cyanobacterial strains, single cells and filaments, and phylogenetic analysis of multiple genomic loci. This study provided systematic revisions of individual cyanobacterial genera and the entire phylum, and suggestions for future study projects.

With an adoption of modern methods of polyphasic approach to the study of cyanobacteria, an increased demand for the revision of the traditional taxonomy has emerged. This thesis is devoted to the systematic revisions of selected terrestrial cyanobacteria at several taxonomic levels. The methodology included thorough morphological characterization of cultured cyanobacterial strains using light and electron microscopy complemented with analyses of the molecular data: DNA sequencing, phylogenetic analyses based on 16S rRNA gene and the adjacent 16S-23S ITS region, and comparison of the predicted secondary structures of this region. Descriptions of new species, genera, families and an in-depth characterization of a previously poorly known family were achieved.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-23T16:20:44Z No. of bitstreams: 1 Willie Anderson dos Santos Vieira.pdf: 939430 bytes, checksum: b3f788b1dafa1b55d7a74abaf64a9110 (MD5) / Made available in DSpace on 2017-03-23T16:20:44Z (GMT). No. of bitstreams: 1 Willie Anderson dos Santos Vieira.pdf: 939430 bytes, checksum: b3f788b1dafa1b55d7a74abaf64a9110 (MD5) Previous issue date: 2012-02-28 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / In the current study the Colletotrichum species isolated from mango in Pernambuco state in Brazil are described, as well as their distribution in different plant tissues. The Colletotrichum isolates are characterized through cultural, morphological, patogenicty and vivirulence data, and from phylogenetic analyses based on a partial sequence of the gene glyceraldehyde-3-phosphate dehydrogenase (GPDH). There was significant difference in isolament frequency among sites and plant tissues. In the locality of Aldeia (site III) it was observed the highest isolation frequency. The old limb was the part of plant most colonized in a higher number of sites. Colletotrichum asianum, C. fructicola, C. cliviae, C. boninense and two unidentified species were found as endophyte in mango, and C. asianum was prevalent over the other. All isolates were pathogenic in mango fruits. The phylogenetic analysis revealed groupings that were congruent with morphological characters, but did not group isolates according to phenotypic characters. There was no distribution pattern of species in different areas, neither in plant tissues. / No presente estudo são relatadas as espécies de isolados de Colletotrichum endofíticos associados a mangueiras no Estado de Pernambuco/Brasil, e sua distribuição nos diferentes tecidos da planta em cinco diferentes áreas. Isolados foram caracterizados cultural e morfologicamente, quanto à patogenicidade e virulência, e através de inferências filogenéticas baseadas na sequência parcial do gene gliceraldeído-3-fosfato desidrogenase (GPDH). Houve diferença significativa na freqüência de isolamento de Colletotrichum em função da área de coleta e do tecido da planta. Na localidade de Aldeia (área III) foi observada a maior freqüência de isolamento de Colletotrichum. O limbo maduro foi a parte da planta mais colonizada por Colletotrichum em um maior número de áreas. Colletotrichum asianum, C. fructicola, C. cliviae, C. boninense e duas espécies não identificadas ocorrem como endófitas em mangueira, e C. asianum foi prevalente sobre as demais. Todos os isolados foram patogênicos em frutos de manga. A análise filogenética revelou agrupamentos que foram congruentes com os caracteres morfológicos analisados, porém não agrupou isolados conforme características fenotípicas. Também não foi observado padrão de distribuição das espécies nas diferentes áreas, nem nos tecidos vegetais.

Our current knowledge of chrysophyte diversity is still generally based on traditional morphospecies descriptions. Accordingly, sequence data exist for the minority of all described species. Consequently, several common morphotypes (e.g. Ochromonas-like flagellate) are scattered across the phylogenetic tree of Chrysophytes. It is evident that the postulated taxonomic diversity certainly does not reflect the real species richness in Chrysophytes. Moreover, recent studies on silica scaled chrysophytes (Mallomonas, Paraphysomonas, Synura) clearly demasked common problematics of (pseudo)cryptic species even within this group possessing relatively good species concept based on the ultrastructure of silica scales and bristles. Contrary, most of chrysophytes are naked flagellates forming stomatocysts as the only solid structure in their life cycles. While single-celled Ochromonas and Spumella were recently revisited using molecular genetic techniques, Uroglena-like colonials remained untreated. Therefore, the main objective of this thesis was to provide a modern taxonomic revision of the widespread colonial chrysophytes causing conspicuous seasonal massive population booms, Synura s.l. and Uroglena s.l., by a polyphasic approach encompassing molecular phylogeny, morphology/ultrastructure and ecology....

A cultura de sorgo granífero no país é amplamente utilizada na alimentação animal. Através deste estudo, decidimos avaliar a micobiota e a ocorrência de ácido tenuazônico em grãos de sorgo cultivados em duas safras. Além disso, através de abordagem polifásica, caracterizamos cepas de E. sorghinum, bem como avaliamos os aspectos ecofisiológicos desta espécie. E. sorghinum foi o fungo mais prevalente nos de grãos de sorgo. O ácido tenuazônico foi detectado na totalidade das amostras avaliadas, com maiores níveis nos grãos cultivados na safra verão. Foi possível verificar considerável variabilidade genética nas cepas de E. sorghinum, apresentando-se como complexo de espécies filogenéticas. Avaliando os fatores abióticos ocorridos no campo, bem como acessando a ecofisiologia de E. sorghinum, foi possível verificar que condições quentes e úmidas são favoráveis a produção de ácido tenuazônico. Estes resultados alertam para presença de compostos tóxicos em grãos de sorgo cultivados no país, bem como contribuem com informações aplicáveis para o manejo desta cultura. / The culture of sorghum in Brazil is widely used in animal feed. The aim of this study was evaluate the mycobiota and occurrence of tenuazonic acid in sorghum grains cultivated in two sowing periods. In addition, through a polyphasic approach, we characterized strains of Epicoccum sorghinum, as well as evaluated the ecophysiological of this species. E. sorghinum was the most prevalent fungus in sorghum grains. Tenuazonic acid was detected in all the samples, with higher levels in the grains grown in the summer crop. It was possible to verify considerable genetic variability in the strains of E. sorghinum, presenting as a complex of phylogenetic species. By evaluating the abiotic factors occurring in the field, as well as the access to an ecophysiology of E. sorghinum, it was possible to verify that hot and wet conditions are favorable for tenuazonic acid production. These results indicate the presence of toxic compounds in sorghum grains cultivated in Brazil, as well as contribute with information for crop management.

The delineation of desmid species was traditionally based on purely morphological features. However, a frequent misinterpretation of morphological variability in desmids has led in the past to extensive taxonomical confusion within this important group of green algae which complicates the interpretation of their biodiversity in freshwater ecology, biogeography and biomonitoring. Consequently, I focused in this thesis predominantly on a previously neglected issue, the application of polyphasic approaches in the species-level taxonomy of desmids. In the most studies, a combination of both traditional morphological and modern molecular phylogenetic and geometric morphometric methods has been used to evaluate the taxonomy of selected desmid species, particularly representatives of the morphologically complex genera Micrasterias and Xanthidium. In two papers, I used the combination of traditional morphological and autecological data to clear up the taxonomy of several morphologically less prominent desmid taxa. Generally, the results of the thesis demonstrated that the way we recently see the diversity and distribution of desmids should be thoroughly changed. The real species diversity is mostly distinctly finer than that estimated by classical morphological taxonomy, often corresponds to varieties of...

A filosfera da Mata Atlântica é um importante nicho de colonização por micro-organismos, cuja comunidade ainda é pouco conhecida. Algumas bactérias associadas à superfície das folhas possuem habilidade de fixar nitrogênio, mineralizar substratos orgânicos e também suprir as árvores com dióxido de carbono e fatores de crescimento. Este trabalho teve como objetivo gerar informações sobre a comunidade cianobacteriana que coloniza a filosfera de algumas plantas da Mata Atlântica e investigar a comunidade diazotrófica presente nesse habitat. Um total de 40 linhagens de cianobactérias da filosfera de Merostachys neesii (bambu), Euterpe edulis (palmeira Juçara), Guapira opposita e Garcinia gardneriana foram isoladas e cultivadas. Os isolados foram caracterizados por análises morfológicas e filogenia do gene 16S RNAr. Essa abordagem permitiu a identificação de uma linhagem do gênero Nostoc, sete Desmonostoc, seis Leptolyngbya, uma Oculatella, cinco Brasilonema, uma Pleurocapsa e duas Chroococcidiopsis. Dezessete linhagens (uma Microchaetaceae, dez Nostocaceae e seis Pseudanabaenaceae) não puderam ser identificadas ao nível de gênero. Vinte e seis linhagens (24 pertencentes às ordens Nostocales e duas à Pseudanabaenales) foram caracterizadas como diazotróficas pela amplificação, sequenciamento e filogenia do gene nifH. Além disso, caracterizou-se o perfil de fixação biológica de nitrogênio da linhagem Desmonostoc sp. CENA362. Com relação ao potencial biotecnológico dessas linhagens, treze isolados foram identificados como potenciais produtores de ácido indol acético (IAA) de acordo com o teste Salkowski. Diversas linhagens apresentaram genes associados à via biossintética do inibidor de protease microviridina, sendo que três delas codificam para novas variantes. Além disso, dez linhagens foram identificadas como potenciais produtoras aeruginosina, três de cianopeptolina e três de microcistina. A comunidade bacteriana diazotrófica avaliada por pirosequenciamento do gene nifH apresentou um perfil de variação espécie-específica para Proteobacteria e uma correlação positiva entre a riqueza e a fixação biológica de nitrogênio. Neste estudo, cianobactérias que habitam a filosfera da Mata Atlântica foram isoladas estão sendo mantidas em condições de cultivo. Novos táxons foram descobertos e vários gêneros conhecidos foram descritos pela primeira vez neste hábitat, o que contribuiu para o aprimoramento da sistemática de Cyanobacteria. As linhagens em cultivo e as informações geradas sobre os seus compostos metabólitos representam uma valiosa fonte para estudos posteriores. Além disso, informações sobre a comunidade bacteriana diazotrófica da filosfera pode auxiliar no entendimento da dinâmica do nitrogênio, elemento limitante e pouco disponível na Mata Atlântica / The phyllosphere of the Atlantic Forest is an important niche for colonization by microorganisms, whose community is still little known. Some bacteria associated with leaf surfaces may possess the ability to fix nitrogen, mineralize the organic substrates and also supply the trees with carbon dioxide and growth factors. Therefore, this study aimed to generate information about cyanobacterial community that colonize the phyllosphere of some plants of the Atlantic Forest and investigated the diazotrophic community in this habitat. A total of 40 strains of Cyanobacteria from the phyllosphere of Merostachys neesii (bamboo), Euterpe edulis (Juçara palm), Garcinia gardneriana and Guapira opposita was isolated and cultivated. The isolates were characterized by morphological analyses and phylogeny of the 16S rRNA gene. This approach allowed the identification of one strain of the genus Nostoc, seven Desmonostoc, six Leptolyngbya, one Oculatella, five Brasilonema, one Pleurocapsa and two Chroococcidiopsis. Seventeen strains (one Microchaetaceae, ten Nostocaceae and six Pseudanabaenaceae) could not be identified at the genus level. Twenty-six strains (24 belonging to Nostocales and two belonging to Pseudanabaenales) were characterized as diazotrophic by amplification, sequencing and phylogeny of nifH gene. Also, it was characterized the profile of biological nitrogen fixation for the strain Desmonostoc sp. CENA362. Regarding the biotechnological potential of these strains, thirteen strains were identified as potential producers of indole acetic acid (IAA) according to Salkowski test. Several strains presented genes involved in the biosynthetic pathway of the protease inhibitor microviridin, three of them encoding putative novel variants. Moreover, ten strains were identified as potential producers of aeruginosin, three of cyanopeptolin and three of microcystin. The diazotrophic bacterial community evaluated by pyrosequencing of the nifH gene showed a profile of variation plant species-specific for Proteobacteria, and a positive correlation between richness and biological nitrogen fixation. In this study, cyanobacteria that inhabiting Brazilian Atlantic Forest phyllosphere were isolated and are been maintained in culture conditions. New taxa were discovered and several known genera were described for the first time in this habitat, which contributed to improvement of the cyanobacterial systematic. The culturable strains and the information generated about their metabolites compounds represent a valuable source for further studies. In addition, information about the diazotrophic bacterial community inhabiting the phyllosphere may help in understanding the dynamics of nitrogen, a limiting and low available element in Atlantic Forest