Most of the detailed studies on periphyton in New Zealand rivers and streams have focused on diatoms. Despite the recent rise of interest in potentially toxic cyanobacterial mats, knowledge of the diversity and ecology of these and other macroscopic growth forms is incomplete. A taxonomic survey was made on periphytic cyanobacteria at 100 locations along Kaituna River and a 1st to 3rd order tributary stream. Samples were taken from runs, riffles and pools in shaded and unshaded locations and from varied substrata from January to December 2011. Descriptions were made of all macroscopic growths. Fifty-six morphospecies were identified of which 29 are new records for New Zealand. Crust components were the most diverse with 23 morphospecies followed by mats (16), gelatinous colonies (5) and epiphytes (7). Five appeared only after growth in enrichment cultures. Twelve morphospecies were isolated into cultures for use in polyphasic assessment. In 16S rDNA phylogenies, Placoma regulare and Heteroleibleinia fontana did not cluster with other members of their traditional families. Nostoc sp. 2 was positioned distant from other Nostoc strains. Comparison of 16S – 23S rRNA internal transcribed spacer compositions for seven mat-forming oscillatorialean morphospecies confirmed their recognition as distinct morphospecies. Amplified fragment length polymorphisms were used to investigate genetic diversity of Nostoc verrucosum in relation to dispersal. This indicated that local dispersal is dominant while cross-catchment dispersal is probably infrequent. Light intensity, substratum type and water conductivity were significant factors influencing spatial patterns of distribution. Higher diversity of crusts, mats and gelatinous colonies was recorded in unshaded locations. Mats and gelatinous colonies were most diverse in Kaituna River and crusts in second to third order streams. Morphospecies in water with high conductivity were restricted to those locations. Spates had a major effect on temporal distribution. An increase in frequency and intensity of spates in spring and winter resulted in greater reduction in cover. Smaller spates caused partial removal followed by rapid regrowth within a week. Major spates caused complete removal of visible cover with re-colonization occurring within three to four weeks. This study has provided a first detailed account of cyanobacterial diversity and ecology in a New Zealand catchment. It provides a basis for long-term monitoring at this site of the effects of changes in climate and in human activities in the catchment.

The aesthetic beauty of a landscape is a very subjective issue: every person has their own opinions and their own idea of what beauty is. However, all people have a common evolutionary history, and, according to the Biophilia hypothesis, a genetic predisposition to liking certain types of landscapes. It is possible that this common inheritance allows us to attempt to model scenic preference for natural landscapes. The ideal type of model for such predictions is the psychophysical preference model, integrating psychological responses to landscapes with objective measurements of quantitative and qualitative landscape variables. Such models commonly predict two thirds of the variance in the predications of the general public for natural landscapes. In order to create such a model three sets of data were required: landscape photographs (surrogates of the actual landscape), landscape preference data and landscape component variable measurements. The Internet was used to run a questionnaire survey; a novel, yet flexible, environmentally friendly and simple method of data gathering, resulting in one hundred and eighty responses. A geographic information system was used to digitise ninety landscape photographs and measure their landforms (based on elevation) in terms of areas and perimeters, their colours and proxies for their complexity and coherence. Landscape preference models were created by running multiple linear regressions using normalised preference data and the landscape component variables, including mathematical transformations of these variables. The eight models created predicted over sixty percent of variance in the responses and had moderate to high correlations with a second set of landscape preference data. A common base to the models were the variables of complexity, water and mountain landform, in particular the presence or absence of water and mountains was noted as being significant in determining landscape scenic preference. In order to fully establish the utility of these models, they were further tested against: changes in weather and season; the addition of cultural structures; different photographers; alternate film types; different focal lengths; and composition. Results showed that weather and season were not significant in determining landscape preference; cultural structures increased preferences for landscapes; and photographs taken by different people did not produce consistent results from the predictive models. It was also found that film type was not significant and that changes in focal length altered preferences for landscapes.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1989. / Includes bibliographical references (leaves 159-172) / Microfiche. / xvii, 172 leaves, bound ill. 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 72-75). / xiv, 75 leaves, bound ill. 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 66-68). / viii, 68 leaves, bound ill. 29 cm

The prevalence of the cyanobacterial metabolites: MIB, geosmin and microcystin in drinking water is a major concern to the water industry as these metabolites can compromise the quality of drinking water. Consequently, effective removal of these metabolites from drinking water is paramount. The combination of ozone (O3) and granular activated carbon (GAC) has been shown to be effective for the removal of these metabolites from drinking water. In this study, the ozonation of MIB and geosmin was affected by the character of natural organic material (NOM). In particular, NOM containing compounds of high UV absorbing properties and high molecular weight (MW) resulted in greater destruction of MIB and geosmin due to the formation of hydroxyl (OH) radicals. / Thesis (PhDAppliedScience)--University of South Australia, 2004.

Thesis (PhD)--University of South Australia, 2003.

Cyanobacteria produce a myriad of structurally unique secondary metabolites with useful bioactive properties. Heterologous expression of a variety of microbial natural compounds has been used to harness their diversity and facilitate their combinatorial biosynthesis. However, these genetic techniques have not been developed for secondary metabolite-producing cyanobacteria. Therefore the genetically manipulable Escherichia coli and Synechocystis sp. PCC6803 were engineered in order to develop effective heterologous hosts and promoters for the expression of cyanobacterial-derived compounds. The phosphopanthetheinyl transferase (PPT), Sppt, from Synechocystis sp. PCC6803 was characterised to determine its ability to activate carrier proteins from secondary metabolite pathways. Despite in silico evidence which suggested Sppt was able to activate a wide range of carrier proteins, biochemical analysis revealed that it is dedicated for fatty acid synthesis. Consequently, E. coli and Synechocystis sp. PCC6803 were engineered to encode a broad-range PPT, from the filamentous cyanobacteria Nodularia spumigena NSOR10, for the activation of carrier proteins from nonribosomal peptide synthesis. Cyanobacterial natural product engineering was also explored with the characterisation of two relaxed specificity adenylation domains (A-domains) from the biosynthetic pathway of the toxin microcystin. The wide variety of microcystin compounds produced by cyanobacterial species suggests that multiple amino acids can be activated by the same A-domain. This was supported by preliminary ATP-[32P]PPi exchange assays and was subsequently harnessed in the production of a variety of dipeptides using two reconstituted modules in vitro. Transposition was investigated as a potential mechanism for the transfer of nonribosomal peptide synthetase gene clusters to heterologous hosts. This was performed via the characterisation of the putative transposase, Mat, physically linked with the microcystin synthetase gene cluster (mcyS). PCR screening, in silico analysis and nitrocellulose filter binding assays indicated that this transposase may have mediated mcyS gene cluster rearrangements but not entire gene cluster mobilisation between species. The potential role of transposases in the natural combinatorial biosynthesis of microcystin has evolutionary implications for the dynamic nature of cyanobacterial genomes and applications for use in the engineering of novel bioactive compounds. Therefore, the results from this study may provide a biotechnological platform for the transfer, expression and combinatorial biosynthesis of novel cyanobacterial-derived natural products.

Large summertime proliferations (or blooms) of the noxious filamentous cyanobacterium Lyngbya majuscula have been observed in the coastal marine waters of Moreton Bay, Queensland. This photosynthetic organism is believed to have a high iron requirement and preliminary studies have shown that the presence of organically complexed iron stimulates growth. Since there is no evidence that Lyngbya produces siderophores to aid iron acquisition, it has been hypothesized that this organism may acquire iron via reduction of ferric complexes to the typically more labile, ferrous form. Both the phylogenetic diversity of the genus Lyngbya and the iron metabolism of L. majuscula are examined in this thesis. Software was developed to assist in the design of peR primers that targeted l6S rRNA, rpoB and Highly Iterated Palindrome (HIP) genetic structures and the subsequent phylogenetic analysis. The mechanism of iron acquisition by L. majuscula and the influence of organic complexation of iron were investigated using radioisotope and chemiluminescence-based techniques. Molecular techniques were also used to investigate the genetics of iron metabolism of L. majuscula. Results of the l6S rRNA analysis indicate that the morpho-genus Lyngbya encompasses a large genetic diversity within the cyanobacteria that is consistent with its reported metabolic and ecological diversity. Five discrete lineages comprised of organisms that fit the morophological definition of Lyngbya were discovered in this analysis. L. majuscula utilises endogenously-produced superoxide as a reductant of ferric complexes to produce the more labile ferrous forms. The nature of the organic complexes has been shown to determine the efficacy of this mechanism. A model of iron acquisition by these reductive processes was developed and was shown to generally describe all known methods of reduction-mediated iron acqUIsItIOn. Finally, the genetics of iron metabolism of L. majuscula was found to be consistent with the mechanism we propose, including the discovery of a component of a ferrous iron uptake mechanism.

Freshwater cyanobacteria produce a wealth of biologically active metabolites, which can adversely affect human and animal health, and cause great economic damage to the fishing, tourism and water-management industries on a global scale. We describe the molecular genetics and biochemistry of biosynthesis for the cyanobacterial toxic alkaloids cylindrospennopsin, paralytic shellfish toxins (PST) and anatoxin-a. Characterisation of the 43 kb cylindrospennopsin biosynthesis gene cluster (cyr), in Cylindrospermopsis raciborskii AWT205 is described. Biosynthesis is initiated via an amidinotransfer onto glycine followed by five polyketide extensions. Rings are formed via Michael additions, while the uracil ring is formed by a novel mechanism. Tailoring reactions, including sulfation and hydroxylation complete the biosynthesis. We describe the characterisation of PST biosynthesis gene clusters in Anabaena circinalis, Aphanizomenon sp. and Lyngbya wollei. These gene clusters span between 28 and 36 kb and contain genes coding for the biosynthesis and export of PSTs. The Lyngbya wollei PST gene cluster represents a 'natural combinatorial biosynthesis' event, explaining its unique toxin profile. A biosynthetic pathway leading to the formation of saxitoxin and its analogues in these organisms is proposed, and a putative insertion/excision site of the PST gene cluster in Anabaena circinalis 310F was identified. Interestingly, PSTs are produced by distantly related organisms via this unique biosynthesis pathway. We Investigated the phylogenetics of PST biosynthesis genes from four different genera of cyanobacteria. The results suggested that PST biosynthesis in cyanobacteria is an ancient trait, whereby the sporadic distribution of PST production in extant isolates of Anabaena circinalis and Aphanizomenon sp. is a result of the repeated loss of the biosynthetic gene cluster. Horizontal gene ransfer also appears to have had a critical influence on PST biosynthesis in Lyngbya wollei. We additionally propose a hypothetical, mixed non-ribosomal peptide synthetase (NRPS)/polyketide synthase (PKS) biosynthesis scheme for anatoxin-a. Degenerate PCR primers were developed, for the specific amplification of mixed NRPSIPKS hybrid ketosynthase (KS) domains. Gene-walking distally to a novel hybrid KS domain in the anatoxin-a producer Planktothrix rubescens, revealed an orphan gene cluster, denoted pro, which spans 24 kb and codes for a mixed NRPS/PKS system, putatively producing an acetylated and sulphated dipeptide.