Offprints of author's articles inserted Bibliography: leaves 180-194

Bibliography: leaves 77-83.

Most marine invertebrates have a complex life cycle involving a benthic adult phase, and a planktonic larval phase. The process whereby tiny larvae are able to locate, settle and metamorphose in a habitat where juveniles are then capable of successfully establishing themselves is a key stage in the life cycle and a central theme of current marine research. Bacterial biofilms are an important settlement cue for many larvae, and it appears that particular strains within environmental communities may be responsible for the inducing ability of some biofilms. The focus of this thesis is the importance of biofilms for larval settlement of the blacklip abalone Haliotis rubra and the sea urchin Heliocidaris erythrogramma. Larval development of the sea urchin Centrostephanus rodgersii was also examined, but this species was problematic for a larval settlement study. H. rubra larval settlement occurred in response to several macroalgal species. Biofilmed (but otherwise abiotic) surfaces did not induce settlement of H. rubra larvae and reduction of surface films of bacteria and diatoms on inducing algae did not reduce the settlement response. Macroalgae, particularly green algal species, may play an important role in the recruitment of H. rubra larvae in the field and can be used to induce settlement in hatcheries. H. erythrogramma settled in response to a range of surfaces with highest settlement on coralline algae. Settlement was reduced by autoclaving plants and treating plants with antibiotics. Molecular and culture based analysis revealed a shift in microbial community structure between plants treated with antibiotics and unmanipulated plants. Many bacterial strains, dominated by the genera Pseudoalteromonas, Shewanella and Vibrio, induced larval settlement. Three probes targeting Pseudoalteromonas, Shewanella and Vibrio were developed for CARD-FISH, enabling quantification of these genera in biofilms on algae. The three genera were found in highest numbers on coralline algae and in variable numbers on the surfaces of other algae. Recruitment of H. erythrogramma also occurs in highest numbers on coralline algae, and in low amounts on co-occurring algae. This is the first example demonstrating that bacteria that induce settlement in the laboratory are also present in the juvenile recruitment habitat.

The PsbL, PsbM and PsbT subunits of photosystem II (PSII) are single-helix membrane-spanning proteins found at the monomer-monomer interface that may stabilize the dimeric complex. This study has characterised strains of Synechocystis sp. PCC 6803 where psbL, psbM and psbT have been interrupted by the insertion of antibiotic-resistance cassettes. The [Delta]PsbL strain exhibited slowed growth that correlated with a disruption in PSII assembly leading to an accumulation of CP43-less PSII monomers. Moreover, the [Delta]PsbL:[Delta]PsbM and [Delta]PsbL:[Delta]PsbT double mutants were not photoautotrophic. In contrast, the [Delta]PsbM and [Delta]PsbT strains grew photoautotrophically and supported oxygen evolution, albeit at reduced rates compared to wild type. S-state analyses showed that the removal of PsbM or PsbT did not affect the donor side reactions of PSII, which includes the oxidation of water, however, the removal of PsbT impaired electron flow between Q[A] and Q[B] on the acceptor side of PSII. Blue-Native PAGE revealed that removal of either PsbM or PsbT was insufficient to entirely disrupt dimer formation; however, the combined removal of PsbM and PsbT resulted in the predominance of monomeric forms of PSII in the [Delta]PsbM:[Delta]PsbT strain. Under high light (2 mE m⁻� s⁻� at 30�C), [Delta]PsbM and [Delta]PsbT cells were considerably more susceptible to photoinactivation than wild type; however, they were able to fully recover in a protein synthesis-dependent manner when returned to moderate light levels (0.03 mE m⁻� s⁻�). A requirement for Psb27 was found in the protein-synthesis-dependent recovery of photoinactivated [Delta]PsbT cells. More significantly, an absolute functional requirement was found for Psb27 in the [Delta]PsbM strain, where functional PSII complexes are not assembled in the absence of Psb27. These results suggest that Psb27 is critical for PSII assembly in the absence of PsbM, and also for the protein-synthesis-dependent recovery of PSII in the absence of PsbT. Moreover, in addition to Psb27, the PsbU subunit of the oxygen-evolving complex was also found to be an absolute functional requirement in the [Delta]PsbM strain, where functional PSII centres are not assembled when both PsbM and PsbU are absent. It appears, therefore, that PsbM has crucial functional interactions with specific extrinsic proteins located in the vicinity of the oxygen-evolving complex. Interestingly, the [Delta]PsbM strain was also found to have a high susceptibility to suppressor mutations, indicating it has important functional roles in the cyanobacterial cell.

Bacteria were isolated from water at Alder Slough, Oregon. Of 15 isolates grown successfully in the medium employed, 100% showed measurable uptake of Zn-65. A growth curve was established for one isolate, a gram-negative rod designated AS-1. Increasing Zn-65 uptake was found generally to correspond with increasing growth of AS-1. The optimum growth temperature for this isolate was 31°C, with very little growth at 37.5°C and 6.7°C. Growth and Zn-65 uptake occurred in a 35 ppt medium from a temperature of 31.0°C to 13.9°C but little growth and no Zn-65 uptake was observed at 8.6°C and 4.4°C. Growth and Zn-65 uptake in a 0 ppt medium occurred from 31.0°C to 5.0°C, with little growth but measurable Zn-65 uptake at 8.9°C and 5.0°C. It was found that 200 ppm Mg added to a culture which had already taken up Zn-65 failed to displace the zinc from the cells. A interaction of the energy source, Casamino Acids, with the Zn-65 spike influenced the results. When cells were lysed, spiked with Zn-65, and the debris removed by centrifugation, 84.8% of the Zn-65 remained in the supernatant. But when cells grown first in Zn-65 spiked medium were lysed and centrifuged, 74.4% of the Zn-65 was found in the debris. It was concluded that bacterial uptake of Zn-65 and other metal cations must be considered in determining the fates of these materials released into the environment. Chemical adsorption phenomena were determined to be a major factor controlling this uptake, with other chemical and biological factors, such as competitive binding by the medium and active uptake or exclusion by the cells, exerting a significant influence that requires further investigation to characterize. / Graduation date: 1971

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980. / Grant no. OCE77-12172, OCE79-19178, OCE79-19264. Includes bibliographical references (leaves 359-373).

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 109-118). Also available on the World Wide Web.

Proefschrift - Delft. / "Stellingen": [4] p. laid in.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Stephen C. Cary, College of Marine and Earth Studies. Includes bibliographical references.

<p>Nitrile hydratases (NHases) are enzymes that catalyse the conversion of organocyanides to amides via a non-hydrolytic hydration reaction. They are industrially relevant enzymes, currently used in the manufacture of nicotinamide and acrylamide. The target of this study belongs to the thermophilic bacteria Geobacillus pallidus.</p>