Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 180-206) Also available in print.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1952. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-68).

No description available.

Advancement in the study of host-microbe interactions has shown that microbes can induce and maintain long lasting changes in gene expression in host cells to facilitate beneficial symbiosis through changes in methylation of the host’s genomic DNA. The beneficial symbiosis between Hawaiian Bobtail squid, Euprymna scolopes and Gram negative bioluminescent bacteria Vibrio fischeri provides an excellent system for studying beneficial microbes’ effect on host DNA methylation. The symbiosis is highly specific, in that only V. fischeri colonizes the squid’s symbiotic organ from a background of 106 diverse bacteria per mL of sea water. DNA methylation (DNAm) refers to the covalent addition of methyl (CH3) groups to the nucleotides of organism’s genomic DNA. The most well researched DNA methylation type is 5- methyl cytosine methylation (5mC). Previous publications show DNAm provides an extra tier of regulation for organisms to control their gene expression, without altering their DNA sequences. Two types of DNAm have been discovered in invertebrate systems: gene promoter methylation and gene body methylation. The amount of methylated cytosine on gene bodies is positively correlated with the specific gene’s expression state. We hypothesize that V. fischeri plays an important role in regulating host DNA methylation during both colonization of the animals (juvenile) and maintenance of the symbiosis I (adult). To start to address this hypothesis, our specific aims are (1) validate DNA methylation in E. scolopes; (2) identify DNA methylation machinery genes in squid at the transcript level and quantify the level of their expression based on state of symbiosis; (3) analyze squid DNA methylation at the whole genome level as well as gene specific level.

Thesis (Ph.D.)--Oregon, Dept. of Biology Vita Bibliography: l. 95-101

Intracellular symbionts are widespread among arthropods, particularly within insects. Obligate symbiotic associations are known to have originated multiple times between the arthropods feeding on nutrient-poor diets and bacteria from various groups. However, exact phylogenetic positions and relationships among these symbiotic lineages are mostly unclear or vague. This thesis consists of an exemplary case study on the most symbiont-rich bacterial group, Enterobacteriaceae, already published in BMC Biology. It uses advanced phylogenetic tools and extended taxonomic sample to establish phylogenetic relationships among individual symbiotic lineages and their phylogenetic affinity to freeliving relatives. To provide it with broader background, the publication is accompanied by a review on general evolutionary forces influencing origin and maintenance of intracellular symbiosis in arthropods. Apart from overviewing the current known diversity of the symbiotic bacteria, it also points out specific drawbacks in inferring symbionts phylogeny and consequences that can phylogeny have on our understanding of intracellular symbiosis.

Made available in DSpace on 2014-06-11T19:30:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-21Bitstream added on 2014-06-13T21:00:30Z : No. of bitstreams: 1 souza_lcb_me_botib.pdf: 124903 bytes, checksum: 978df574d824794b674c6c9893da05b4 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho teve como objetivo avaliar parâmetros comportamentais e químicos entre o caranguejo-aranha Libinia spinosa e sua anêmona Calliactis tricolor. Três hipóteses foram testadas através de experimentos laboratoriais. O experimento 01 testou qual sexo e estágio de maturidade de L. spinosa interage de maneira mais eficiente com C. tricolor. Foram utilizados 10 réplicas de cada grupo demográfico do caranguejo (a exceção de fêmeas jovens, com apenas 06 réplicas) e 3 anêmonas (previamente fixadas em uma pedra) para cada réplica. Os resultados indicam que os caranguejos adultos fixam mais anêmonas (G=4,7596;p=0,0291) e são mais rápidos para encontrá-las (F=5,03970;p=0,031814), e as fêmeas ovigeras fixam mais anêmonas (G=5,3002;p=0,0213) quando comparadas as fêmeas não ovigeras. O experimento 2 avaliou se o reconhecimento entre os parceiros depende de estímulo visual ou químico. Foram utilizadas apenas fêmeas ovígeras para os demais experimentos, baseado nos resultados do experimento 1. Dois tratamentos foram utilizados: 1) uma anêmona atrás de uma placa preta opaca; 2) uma anêmona atrás de uma placa transparente. Não foram observadas diferenças entre os tratamentos (T=0,978763;p=0,347018), o que nos indica que os caranguejos encontram as anêmonas por pistas químicas. No experimento 3 foi testado o tempo e a duração do reconhecimento e aclimatação entre L. spinosa e C. tricolor. Em uma primeira fase todos os exemplares (21) de L. spinosa fixaram uma anêmona; após 3h de fixação foram separados. Na seqüência, 4 tratamentos se seguiram: Tratamento 1 e 2: 3h de separação e novo contato com a mesma anêmona, e com outra anêmona, respectivamente; Tratamento 3 e 4: 4 dias de separação e novo contato com a mesma anêmona, e com outra anêmona, respectivamente. Não houve diferença em nenhum dos tratamentos... / The present research aimed to assess behavioral and chemical parameters between spider-crab Libinia spinosa and its symbiotic sea anemone Calliactis tricolor. Three hypotheses were tested through laboratorial experiments. The experiment 1 tested which genre and age of L. spinosa interacts more efficiently with C. tricolor. Were used 10 replications of each demographic group of spider-crabs (except young females, only with 6 replications) and 3 anemones (previously placed in one rock) for each replication. The results suggested that adult spider-crabs placed more (G=4,7596;p=0,0291) and readily find anemones (F=5,03970;p=0,031814) and the ovigerous females placed more anemones (G=5,3002;p=0,0213) compared with non-ovigerous. The experiment 2 evaluated if reconnaissance between partners depends on visual or chemical cues. The other experiments used only ovigerous females, based on results of experiment 1. Two treatments were used: 1) one anemone behind opaque black plate; 2) one anemone behind translucid plate. There were no differences between treats (T=0,978763;p=0,347018), indicating that crabs find anemones through chemical cues. The experiment 3 tested the time and duration of reconnaissance and acclimation between L. spinosa and C. tricolor. In the first phase all specimens (21) of L. spinosa placed one anemone; and were separated after 3 hours of placement. Further, 4 treatments followed: Treatment 1 and 2: 3 hours separated and new contact with the same and other anemone, respectively; Treatment 3 and 4: 4 days separated and new contact with the same and other anemone, respectively. There were no difference among treats (Treatment 1: T=0,236853;p=0,816202; Treatment 2: T=0,856921;p=0,402754; Treatment 3: T=0,743289;p=0,478564; Treatment 4: T=-1,52701;p=0,157747), indicating that acclimation period do not persist when partners were separated... (Complete abstract click electronic access below)