No description available.

No description available.

Symbiotic relationships of bacteria with higher organisms are commonly observed in nature; however, the functional role of these relationships is only rarely understood. This is particularly evident in epibiotic bacterial associations in the marine environment where the bacteria are often a diverse ensemble of microorganisms, thus complicating the identification of the functionally important members. Classical microbiological techniques, relying primarily on culturing these organisms, have provided an incomplete picture of these relationships. Molecular genetic techniques, focusing on the analyses of bacterial 16S rRNA sequences cloned directly from natural microbial populations, are now available which allow a more thorough examination of these associated bacterial populations. This study sought to characterize the epibiotic bacterial population associated with a very unique organism, Alvinella pompejana, using such a molecular approach. Alvinella pompejana is a polychaetous annelid that inhabits active deep-sea hydrothermal vent sites along the East Pacific Rise. This worm colonizes the walls of actively venting high temperature chimneys and is thought to be one of the most thermotolerant metazoans known. The chimney environment is characterized by high concentrations of sulfide and heavy metals in the vicinity of the worm colonies. A morphologically diverse epibiotic microflora is associated with the worm's dorsal integument, with a highly integrated filamentous morphotype clearly dominating the microbial biomass. It has been suggested that this bacterial population participates in either the nutrition of the worm or in detoxification of the worm's immediate environment; however, previous studies have been unable to confirm such a role. The primary goal of this study is to phylogenetically characterize the dominant epibionts through the analysis of 16S rRNA gene sequences. Nucleic acids were extracted from bacteria collected from the dorsal surface of Alvinella pompejana. 16S rRNA genes were amplified with universal bacterial primers by the polymerase chain reaction (PCR). These genes were subsequently cloned and the resulting clone library was screened by restriction fragment length polymorphism (RFLP) analysis to identify unique clone types. Thirty-two distinct clone families were found in the library. Four of these families were clearly dominant, representing over 65% of the library. The main assumption in this study is that the numerical dominance of the phylotypes in the starting population will be reflected in the clone library. Thus, representative clones from the four most abundant clone families were chosen for complete gene sequencing and phylogenetic analysis. These gene sequences were analyzed using a variety of phylogenetic inference methods and were found to be related to the newly established epsilon subdivision of the Proteobacteria. In future studies, these gene sequences will be used to construct specific oligodeoxynucleotide probes which can be used to confirm the morphology of the clone types in the epibiont population. / Graduation date: 1995

Thesis (M.Sc.)--Memorial University of Newfoundland, 2001. / Includes bibliographical references.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

No description available.

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Ecology and Evolution." Includes bibliographical references (p. 186-199).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

In the late 1980's abalone culturalists noticed reduced growth rate and shell deformities in some abalone stocks. These problems were the result of infestations by a shell boring polychaete, Terebrasabella heterouncinata. Under intensive abalone culture conditions the level of infestation can reach epidemic proportions and there are often severe consequences for the host abalone. Heavy sabellid infestation levels have placed the economic viability of several South African farms under threat. This study formed part of an ongoing project that is aimed at investigating the basic biology of Terebrasabella heterouncinata. The majority of abalone farmers in South Africa feed their abalone either naturally occurring kelp (Ecklonia maxima) or the formulated abalone feed, Abfeed. Farmers have suggested that the use of Abfeed is associated with higher sabellid infestation levels and changing the abalone diet from Abfeed to kelp helps reduce sabellid infestation. Speculation has arisen indicating that older, slower growing abalone are more susceptible to sabellid infestation. The effect of host abalone diet history and their growth on sabellid settlement success, morphometries and reproduction was quantified. To better understand the plasticity of the expression of life history traits the variability of morphometric and reproductive characteristics was compared between different farm environments. And more...

Orientador: Antonia Cecília Zacagnini Amaral / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T03:18:37Z (GMT). No. of bitstreams: 1 Silva_CamilaFernandada_M.pdf: 2054287 bytes, checksum: 3eb2bbba7d82fc1653b87868f315280a (MD5) Previous issue date: 2013 / Resumo: Os bancos de mitilídeos consistem de uma matriz física de indivíduos vivos e mortos e fragmentos de concha, interconectados por um emaranhado de filamentos do bisso. O estudo da caracterização estrutural de dois bancos de mitilídeos (Mytella charruana) foi realizado entre abril de 2006 e fevereiro de 2007, nas praias Camaroeiro e Cidade (costa norte do Estado de São Paulo). Amostras mensais foram obtidas com o auxílio de um delimitador de 0,04 m2 de área, até 20 cm de profundidade, em três níveis do banco (inferior médio e superior). Foi analisada a densidade de M. charruana, bem como os parâmetros perfil praial, salinidade da água intersticial, temperaturas do ar e do sedimento, conteúdo de calcário e matéria orgânica do sedimento e granulometria. A densidade média mensal de M. charruana do banco Camaroeiro variou de 13,66 inds/0,04 m2 (dp = 12,09) a 46 inds/0,04 m2 (dp = 11,53), e a do banco Cidade, de 57,33 inds/0,04 m2 (dp = 54) a 156 inds/0,04 m2 (dp = 43,31). O perfil da Praia do Camaroeiro permitiu classificá-la como dissipativa e, o da Cidade, como intermediária do tipo terraço de baixamar. A salinidade média da água intersticial do Camaroeiro variou de 26,33 (dp = 4,04) a 33,33 (dp = 1,15) e a da Cidade, de 27,5 (dp = 3,53) a 33,33 (dp = 1,15). A temperatura média do ar variou de 17ºC (dp =0) a 30,5ºC (dp =0) e a do sedimento, de 18ºC (dp =0) a 29ºC (dp = 0), em ambos os bancos. O conteúdo médio de calcário e matéria orgânica oscilou entre 6,73% (dp = 2,58) e 10,59% (dp = 1,53) e entre 2,17% (dp = 1,26) e 6,07% (dp = 2,07), respectivamente, no Camaroeiro e entre 8,39% (dp = 2,53) e 12,13% (dp = 1,91) e entre 3,56% (dp = 0,22) e 6,11% (dp = 0,48) na Cidade. A fração do sedimento predominante em ambos os bancos foi a de areia muito fina, com algumas variações ao longo do ano, e classificada principalmente como pobre a moderadamente selecionada. Ao final do período de estudo, os bancos de mitilídeos desapareceram, mas devem surgir novamente ao longo do tempo. Esse fato ocorre devido à dinâmica populacional e/ou reprodutiva de Mytella charruana, organismo estruturador dos bancos, e também à morfodinâmica praial dessa região / Abstract: Mussel beds are aggregations of live and dead mussels, shell fragments and byssus thread. The structural characterization of two soft-bottom mussel beds of Mytella charruana was studied between April 2006 and February 2007 at Camaroeiro and Cidade beaches (northern coast of São Paulo State). Mensal samples were taken with a 0,04 m2 corer, until a depth of 20 cm, in the lower, middle and upper levels of the beds and analyzed the density of M. charruana, beach slope, interstitial salinity, sediment and air temperatures, calcareous and organic matter content of the sediment and granulometry. The mean density of M. charruana ranged between 13,66 inds/0,04 m2 (sd = 12,09) and 46 inds/0,04 m2 (sd = 11,53) at Camaroeiro, and between 57,33 inds/0,04 m2 (sd = 54) and 156 inds/0,04 m2 (sd = 43,31) at Cidade. The Camaroeiro beach slope enabled the classification of the beach as a dissipative state while the Cidade beach slope, as a low-tide terrace. The mean Camaroeiro interstitial salinity ranged between 26,33 (sd = 4,04) and 33,33 (sd = 1,15); and the mean Cidade interstitial salinity ranged between 27,5 (sd = 3,53) and 33,33 (sd = 1,15). Mean air temperature ranged between 17ºC (sd = 0) and 30,5ºC (sd = 0) and mean sediment temperature, between 18ºC (sd = 0) and 29ºC (sd = 0), in both mussel beds. Mean calcareous and organic matter contents ranged, respectively, from 6,73% (sd = 2,58) to 10,59% (sd = 1,53) and from 2,17% (sd = 1,26) to 6,07% (sd = 2,07) at Camaroeiro and ranged, respectively, from 8,39% (sd = 2,53) to 12,13% (sd = 1,91) and from 3,56% (sd = 0,22) to 6,11% (sd = 0,48) at Cidade. The granulometric composition of both mussel beds was very similar, with a predominance of moderate and poorly-sorted fine sand. At the end of the study period, the mussel beds disappeared, but must appear again with time. This can happen due to the population and/or reproductive dynamic of Mytella charruana, the organism who structures the mussel beds, and also due to the beach morphodynamic of the area / Mestrado / Ecologia / Mestra em Ecologia