Doctor of Philosophy / Genetics Interdepartmental Program - Biology / Susan J. Brown / Understanding evolutionary processes that structure genetic variation associated with lineage diversification and speciation is a central problem. Shifts in host plant use by insect herbivores and subsequent divergence in mating signals can lead to sexual isolation, especially when selection for specialization on different hosts restricts gene flow among populations. The grasshopper Hesperotettix viridis (Thomas) is an oligophagous grasshopper feeding on plants primarily in the host plant genera Gutierrezia and Solidago in Kansas. I used mitochondrial and microsatellite genetic markers to evaluate the diversification pattern and underlying evolutionary mechanisms of two putative host races of H. viridis. I also quantified host preferences, the degree of sexual isolation among putative host races and divergence in cuticular attributes to identify the nature and origins of initial barriers that isolated populations in the formative stages of divergence. mtDNA data revealed a star-shaped phylogeny, suggesting isolation in a single refugium ~110,000 years ago based on a molecular clock, followed by rapid population expansion. Microsatellite data reveal significant host-based genetic differentiation and structuring in H. viridis populations in Kansas, including a microsatellite locus under strong divergent selection. Neutral microsatellite loci did not reveal a differentiation pattern specific to host plant use. Significant host-based preferences by individuals that fed on two host plant groups were detected in host paired-feeding preference studies. No-choice mate selection experiments revealed preferences for individuals collected from the same host species independent of location with little mating observed between individuals from different host species. Significant differentiation in color and cuticular composition among different host plant races within the study area was also detected. Correlations between host choice, mate choice and phenotypic divergence were observed and this host associated divergence appears to have a genetic basis. Based on the results of this study, I conclude that divergent selection for host plant use underlies observed sexual isolation among populations in this species. Hesperotettix viridis populations in Kansas that fed on Solidago and Gutierrezia species represent two incipient host races, early stages of diversification that could lead to speciation in insect herbivores.

The present study was undertaken to evaluate the effects of stress on crystalline style characteristics in bivalves of Crassostrea angulata, Meretrix lusoria, and Perna viridis. Firstly, the crystalline style morphological characteristics in normal submerged condition was examined. The presence percentage of crystalline styles in C. angulata collected from different months ranged from 0 to 73%. While, it was 100% in M. lusoria and P. viridis. Secondly, the crystalline style morphological characteristics were investigated under stresses of starvation, hypoxia and desiccation. In C. angulata, the crystalline styles were absent after treated with each of the unfavorable conditions for 1 hour. In M. lusoria, under starvation and hypoxia conditions for 72 hours, the presence percentage of crystalline styles was significantly decreased. Even more, the presence percentages of crystalline styles in M. lusoria reduced to 22% when treated with desiccation for 2 hours. In P. viridis, the presence percentage of crystalline styles was 100% under starvation and hypoxia for 72 hours. In contrast, the mussels were totally dead under desiccation for 72 hours. By comparison, desiccation had greater influence on the three bivalves than starvation and hypoxia based on the standardized crystalline style wet weight (crystalline style wet weight/ shell length). Additionally, the presence percentage of crystalline styles in C. angulata was also influence by fed. In all, among the three examined species, oyster C. angulata is the most sensitive one to unfavorable conditions.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-02-07T17:06:02Z No. of bitstreams: 1 texto completo.pdf: 3400245 bytes, checksum: b57a0d743c1ea165d35b1ffebb7e5dbc (MD5) / Made available in DSpace on 2017-02-07T17:06:02Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3400245 bytes, checksum: b57a0d743c1ea165d35b1ffebb7e5dbc (MD5) Previous issue date: 2016-07-19 / Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A disponibilidade de gás oxigênio (O2) é uma das principais forças que moldam a evolução dos organismos vivos e é essencial para a sobrevivência das plantas. A deficiência parcial (hipóxia) ou total (anóxia) de gás oxigênio é componente importante do estresse de alagamento. Para o aprofundamento do conhecimento genético, a transcriptômica possibilita identificar genes envolvidos nos mecanismos de respostas, e a transformação desses genes em plantas permite avaliar seus efeitos. Com o objetivo de caracterizar genes responsivos à deficiência de oxigênio e identificar genes candidatos para tolerância ao alagamento, analisamos dados de RNA-seq de raízes das cultivares de soja Embrapa 45 (tolerante ao encharcamento do solo) e BR 4 (sensível ao encharcamento) sob hipóxia. Das diferenças entre as duas cultivares, Embrapa 45 apresentou menor número de genes up-, maior quantidade de genes down- regulados, e maior expressão dos genes que codificam phosphoglucomutase (Glyma05g34790), unknown protein related to N-terminal protein myristoylation (Glyma06g03430), protein suppressor of phyA-105 (Glyma06g37080) e fibrillin (Glyma10g32620). Dados de RNA-seq e qRT-PCR da hemoglobina não simbionte Glyma11g12980 indicaram divergência estrutural desse gene entre as cultivares. Em comum entre as duas cultivares, mudanças na abundância de transcritos envolvidos no metabolismo de aminoácidos e derivados sugerem perturbação destes em modificações do tRNA, acurácia/eficiência traducional e estresse do retículo endoplasmático (RE) sob hipóxia. Também observamos que grupos de genes (estáveis, up- e down-regulados) diferem quanto à frequência de elementos cis TATA box, ABREs (ABA-responsive elements) e CRT/DREs (C-repeat/dehydration-responsive elements), assim como em estrutura, composição e uso de códons sinônimos. Especulamos que cis elementos ABRE podem mediar expressão gênica independentemente de ABA em raízes de soja sob hipóxia. Por fim, a nosso conhecimento, somos os primeiros a demonstrar viabilidade de se transformar Setaria viridis (espécie modelo de monocotiledôneas C4) mediada por Agrobacterium por meio da técnica floral dip, que não demanda cultura de tecidos nem regeneração de plantas transgênicas. Assim como em arabidopsis, espécie modelo de dicotiledôneas C3, floral dip em S. viridis pode acelerar estudos genéticos e de genômica funcional (inclusive ao estresse de alagamento) de gramíneas importantes para alimentação humana e animal, fibras e biocombustíveis, tais como cana-de-açúcar, Miscanthus, capim- elefante, Brachiaria, sorgo e milho. / Oxygen gas (O2) availability is one of primary forces shaping the evolution of living organisms and essential for land plants survival. Partial (hypoxic) or total (anoxic) oxygen gas deficiency is important component of flooding stress. For deepening the genetic knowledge, transcriptomics identify genes involved in stress response mechanisms, and transformation of these genes in plants allows to evaluate its effects. In order to characterize genes responsive to oxygen deficiency and identify candidate flooding tolerance genes we analyzed root RNA-seq data from flood-tolerant Embrapa 45 and flood-sensitive BR 4 soybean cultivars under hypoxic stress. From differences between the two cultivars, Embrapa 45 showed less up- and more down-regulated genes, and stronger induction of phosphoglucomutase (Glyma05g34790), unknown protein related to protein N-terminal myristoylation (Glyma06g03430), protein suppressor of Phya- 105 (Glyma06g37080), and fibrillin (Glyma10g32620). RNA-seq and qRT-PCR data of non-symbiotic hemoglobin Glyma11g12980 indicated structural divergence of this gene between cultivars. In common between the two cultivars, transcriptional changes in amino acids and derivative metabolic process suggest its disturbance in tRNA modifications, translation accuracy/efficiency, and endoplasmic reticulum (ER) stress under hypoxia. In addition, genes groups (stable, up-, and down-regulated genes) differed in promoter TATA box, ABREs (ABA-responsive elements), and CRT/DREs (C-repeat/dehydration-responsive elements) frequency, as well as in structure, composition, and codon usage. We speculate that cis-acting ABREs can mediate gene expression independent of ABA in hypoxic soybean roots. Finally, to our knowledge, we first report Agrobacterium-mediated transformation method in Setaria viridis (C4 monocotyledonous model species) using floral dip, which does not require tissue culture nor transgenic plant regeneration. As in arabidopsis, C3 dicotyledonous model species, floral dip in S. viridis may accelerate genetic studies and functional genomics (including flooding stress) of important food–feed–fiber–fuel grass crops such as sugarcane, Miscanthus, elephant grass, Brachiaria, Sorghum and maize.

Production of fine sediments in reef environments is a poorly understood but probably significant process. On the Great Barrier Reef, Cliona viridis is locally abundant. The sponge has been found from Lizard Island in the north, down to the southern part of the Central Region, and it is likely even more widespread. Although on individual reefs the sponge may occur almost anywhere, it is most abundant on lagoon path reefs ("bommies" in Australian), where it overgrows the substrate and bores to a constant depth of about 1.3cm. Sponge infestation reaches a maximum at a depth of 4 m covering almost 8% of the vertical sides of bommies. It is frequently the dominant benthic organism. Serial underwater photography demonstrates that colonies can expand laterally at a rate of about 1 cm yr⁻¹ removing approximately 40% of the substrate. This species is a major producer of fine sediment on the Great Barrier Reef. / Thesis / Master of Science (MS)

Made available in DSpace on 2015-03-26T13:30:53Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1175860 bytes, checksum: 8d49f98b8b8a4ab64b4d0d84434f5297 (MD5) Previous issue date: 2007-02-14 / Universidade Federal de Viçosa / The green cochineal Coccus viridis (green) (Hemipetera: Coccidae) causes problems in sapling plants of Coffea arabica and in parts of the canopy under low luminosity. Plant fertilization with nutrients like nitrogen and potassium may influence the survival, the development, the growth, the reproduction and the behavior of insects. The impact of the application of nitrogen and potassium doses may have direct effects (via nutrients on leaves) and indirect (on phytochemists) on C. viridis. Another impact of nitrogen and potassium fertilization on the interaction of C. viridis on coffee trees is on the tolerance of the plants to the losses caused by this insect-pest. So far, this work aimed to study the relation among nitrogen and potassium doses given to the plants, concentration of foliar phytochemical compounds and attack of C. viridis and also to determine the losses incurred to plants of C. Arabica by this insect. This research was conducted in a green house. Deficient, normal and excessive nitrogen and potassium fertilizations were used. Each treatment was composed of two plants (infested and uninfested). Nymphs and adults were counted every week. The phytochemical and nutrient levels on leaves were determined for infested plants, and dry material of roots, stem, leaves and overall for uninfested plants. The analysis conducted were those of Pearson´s correlation, path and multiple linear regressions. Raised the nitrogen levels in the nutritive solution, the intensity of nymph and adult attacks of C. viridis were observed throughout the experiment period. A direct impact of those nutrients was observed through the increasing levels of nitrogen on leaves. On the other hand, the indirect effect is due to the decreasing of caffeine levels, chlorogenic acid and cafeic acid on leaves that may act as alomones on C. viridis. It was also observed that plants when fertilized with larger doses of nitrogen and potassium presented smaller loss of foliar, stem and total dry material as well as a smaller diameter reduction when attacked by that pest. / A cochonilha verde Coccus viridis (Green) (Hemiptera: Coccidae) causa problemas em plantas jovens de Coffea arabica e em partes do dossel com baixa luminosidade. A adubação das plantas com nutrientes como o nitrogênio e o potássio pode influenciar a sobrevivência, o desenvolvimento, o crescimento, a reprodução e o comportamento dos insetos. O impacto da aplicação de doses do nitrogênio e do potássio pode ter efeitos diretos (via nutrientes na folha) e indiretos (sobre os fitoquímicos) sobre C. viridis. Outro impacto da adubação nitrogenada e potássica sobre a interação de C. viridis no cafeeiro é na tolerância das plantas às perdas causadas por este inseto-praga. Assim este trabalho teve por objetivo estudar as relações entre doses de nitrogênio e de potássio fornecidas às plantas, concentração de compostos fitoquímicos foliares e ataque de C. viridis, e ainda, determinar as perdas em vigor causadas por este inseto a plantas de C. arabica. Esta pesquisa foi conduzida em casa de vegetação. Utilizaram-se adubações de nitrogênio e de potássio em deficiência, normal e excessiva. Cada tratamento foi composto por duas plantas (infestada e não infestada). Semanalmente, contaram-se os números de adultos e de ninfas nas plantas. Foram determinados os teores dos fitoquímicos e nutrientes nas folhas para plantas infestadas e matéria seca das raízes, caule, folhas e total para plantas não infestadas. Realizou-se análise de correlação de Pearson, análise de trilha e regressão linear múltipla. Verificou-se que com a elevação dos teores de nitrogênio na solução nutritiva ocorreu aumento da intensidade de ataque de ninfas e de adultos de C. viridis ao cafeeiro ao longo do tempo. Verificou-se que estes nutrientes têm impacto direto através do aumento dos teores de nitrogênio nas folhas. Já o efeito indireto deve-se à redução dos teores de cafeína, ácido clorogênico e ácido cafeico nas folhas, os quais atuam possivelmente como alomônios sobre C. viridis. Observou-se que plantas adubadas com maiores doses de nitrogênio e de potássio tiveram menores perdas de matéria seca total, foliar, caule e menor redução do diâmetro quando atacadas pela praga.

L’endosymbiose trophique établie entre un hôte Cnidaire et ses symbiotes Dinoflagellés photosynthétiques est à l’origine du succès évolutif des écosystèmes coralliens. Les symbiotes sont internalisés par un mécanisme de phagocytose et maintenus dans les cellules du gastroderme de l'hôte. La symbiose est régie par un dialogue moléculaire intime entre les deux partenaires, interrompu lors de perturbations environnementales ou anthropiques, responsables du déclin mondial des récifs coralliens. Les objectifs de mon projet de recherche sont de définir les acteurs moléculaires localisés à l’interface symbiotique chez l’anémone de mer, Anemonia viridis. Premièrement, nous avons étudié les mécanismes cellulaires impliqués dans différents types de rupture de la symbiose et mis en évidence des phénomènes d’apoptose, nécrose et symbiophagie. Parallèlement, nous avons caractérisé chez l’anémone les gènes npc1 et npc2, impliqués chez les vertébrés dans le transport endosomal de stérols, et dont l’expression est modulée par l’état symbiotique. Nous avons pu montrer que le gène npc2d est issus d’une duplication et vraisemblablement d’une sub-fonctionnalisation et que les protéines NPC1 et NPC2 sont exprimées au voisinage des symbiotes. Nous proposons donc que la protéine NPC2-d soit utilisée comme marqueur de l’état de santé des Anthozoaires symbiotiques et que la protéine NPC1 soit un marqueur de la membrane périsymbiotique. Nous avons également développé un protocole afin d’identifier les protéines associées à l’interface symbiotique entre les deux partenaires. A terme, les cibles identifiées permettront une meilleure compréhension des mécanismes qui régulent la relation symbiotique. / The trophic endosymbiosis interaction between a cnidarian host and its photosynthetic dinoflagellatessymbionts form the basis of coral reef ecosystems. Cnidarians host their symbionts in gastrodermis cells, in a phagocytosis-derived vacuole. Establishment and maintenance of the symbiotic interaction depend on an intimate molecular communication between the two partners. However, environmental and/or anthropogenic disturbances can lead to the breakdown of the symbiotic association, which is responsible for the worldwide decline of coral reefs. The main objectives of my research project are to improve the knowledge regarding symbiosis maintenance and disruption mechanisms, but also to define the molecular key players involved at the symbiotic interface in the sea anemone, Anemonia viridis. First, we have described the cellular mechanisms involved in the different types of symbiosis breackdown. Meanwhile, the characterization of npc1 and npc2 genes (involved in endosomal sterol transport), showed a duplication and a sub-functionalization of the npc2d gene. Both NPC1 and NPC2 proteins are expressed around symbionts. We therefore suggest that the duplicated protein NPC2-d is a biomarker of symbiosis health and that NPC1 protein is a marker of the perisymbiotic membrane. We then developed a protocol to characterize the proteome of the symbiotic interface between the two symbiotic partners. The newly-identified symbiotic key players will increase the general knowledge on the symbiotic interaction and its regulation during both stable and bleaching conditions.

<p>Biodiversity in forests depends on long canopy continuity and existence of different elements which function as substrates for varying organisms. Bryophytes often occupy specific substrates with a patchy distribution. The aim of this thesis was to increase the ecological knowledge about two threatened moss species; <i>Buxbaumia viridis</i>, inhabiting decaying wood, and <i>Neckera pennata</i>, inhabiting bark of base-rich deciduous trees. </p><p>Establishment from spores was investigated in <i>Buxbaumia viridis</i> and <i>Neckera pennata</i> and models were created to predict germination of spores as a function of pH and water potential. The effects of pH, phosphorus and nitrogen concentration were studied in <i>Buxbaumia viridis</i>, both on spore germination and on sporophyte occurrences in the field. Colony growth in relation to precipitation and microhabitat variables was studied in <i>Neckera pennata</i>, and a model was used to predict growth of colonies over time. Metapopulation dynamics of <i>Buxbaumia viridis</i> were analyzed as an effect of precipitation, habitat quality and patch quantity. A spatial explicit patch occupancy model was constructed to simulate metapopulation sizes and extinction risk over 100 years.</p><p>The quality of the substrate was very important for spore establishment. Germination success increased with increasing pH in both species. <i>Buxbaumia viridis</i> was less sensitive to low pH than <i>Neckera pennata</i> when water was freely available. However, there was a strong interaction between pH and water potential in prediction of the final cumulative germination: the spores reacted positively to one factor only when the other factor was in a favourable range.</p><p>Precipitation, moisture holding capacity and interference competition were the main factors affecting colony growth of <i>Neckera pennata</i>. <i>Buxbaumia viridis</i> showed large fluctuations in number of occupied patches among years. Both colonizations and extinctions were highly related to precipitation. Spore germination and sporophyte occurrences in the field were positively related to phosphorus concentration and pH of the substrate.</p>

Biodiversity in forests depends on long canopy continuity and existence of different elements which function as substrates for varying organisms. Bryophytes often occupy specific substrates with a patchy distribution. The aim of this thesis was to increase the ecological knowledge about two threatened moss species; Buxbaumia viridis, inhabiting decaying wood, and Neckera pennata, inhabiting bark of base-rich deciduous trees. Establishment from spores was investigated in Buxbaumia viridis and Neckera pennata and models were created to predict germination of spores as a function of pH and water potential. The effects of pH, phosphorus and nitrogen concentration were studied in Buxbaumia viridis, both on spore germination and on sporophyte occurrences in the field. Colony growth in relation to precipitation and microhabitat variables was studied in Neckera pennata, and a model was used to predict growth of colonies over time. Metapopulation dynamics of Buxbaumia viridis were analyzed as an effect of precipitation, habitat quality and patch quantity. A spatial explicit patch occupancy model was constructed to simulate metapopulation sizes and extinction risk over 100 years. The quality of the substrate was very important for spore establishment. Germination success increased with increasing pH in both species. Buxbaumia viridis was less sensitive to low pH than Neckera pennata when water was freely available. However, there was a strong interaction between pH and water potential in prediction of the final cumulative germination: the spores reacted positively to one factor only when the other factor was in a favourable range. Precipitation, moisture holding capacity and interference competition were the main factors affecting colony growth of Neckera pennata. Buxbaumia viridis showed large fluctuations in number of occupied patches among years. Both colonizations and extinctions were highly related to precipitation. Spore germination and sporophyte occurrences in the field were positively related to phosphorus concentration and pH of the substrate.

The European green lizard, Lacerta viridis, is in the Bohemia region stated as critically endangered species. Populations in this region are located beyond the northern border of continuous range of this species and are closely related to the "riverine phenomenon", and deeply engorged river valleys. The chosen locality in Tiché údolí is a subject to a long-term conservational management aimed to strengthen and maintain abundance of the local population. This management is a direct output of a previous study of this population performed in years 1995-1997. Main goal of the presented study is to compare current population characteristics with the older study. The locality has been visited 119 times in years from 2011 to 2014. The studied population now displays higher abundance and inhabits a larger area. The author also performed a spatial analysis of the places with presence of an observed individual in order to determine and evaluate significance of the chosen abiotic factors for habitat discrimination. The results indicate that positive discrimination is based on the presence of a rock debris and a hiding place. Strongest factors towards negative discrimination were high percentages of grass and high vegetation coverage. This study also contains and discusses ecological, ethological and...

Dans ce travail nous avons réalisé une évaluation de la composition et des activités biologiques des HEs extraites de L. stoechas récoltées sur 11 sites dans le nord de l'Algérie. Les HEs ont été analysées par GC/FID et GC/MS, où un total de 121 composés ont été identifiés, représentant de 69.88 à 91.2% du contenu total de l'huile. Les principaux constituants étaient le fenchone (11.27-37.48%), le camphre (1.94-21.8%), le 1,8-cinéol (0.16-8.71%) et le viridiflorol (2.89-7.38%). Les activités biologiques in vitro ont démontré que les activités de piégeage du radical DPPH et l'oxydation des lipides du couple β- carotène/acide linoléique différaient d'un facteur 8 et étaient liées à différents ensembles de molécules. Nos 11 HEs ont présenté de bonnes activités antimicrobiennes envers la plupart des 16 souches pathogènes testées à des valeurs de concentration minimale inhibitrice (CMI) allant de 0.16 à 3.5 mg/ml. A l'aide d'amorces dégénérées nous avons isolé trois ADNc en pleine longueur, LpFENS, LpPINS et LpGEAS, de feuilles de L. pedunculata. Six ADNc homologues en pleine longueur, LSFENS, LsPINS, LsGEAS, LvFENS, LvPINS et LvGEAS, ont été également isolés des feuilles de L. stoechas et L. viridis en utilisant des amorces spécifiques aux trois premiers ADNc clonés. L'expression hétérologue dans E. coli et l'analyse de l'activité catalytique par GC/MS des enzymes natives recombinantes purifiées de ces TPSs ont permis leur caractérisation fonctionnelle en tant que, α-fenchol synthases (LpFENS, LsFENS et LvFENS), α-pinène synthases (LpPINS, LsPINS et LvPINS) et germacrène A synthase (LpGEAS, LsGEAS et LvGEAS)