In regard to the more and more restrictive legislations on the use of organotins in antifouling coatings the need for the development of 'environmentally friendly' antifouling formulations becomes urgent. This study was initiated by the screening of the antifouling activity of Scottish algae against marine fouling bacteria aI;ld was followed by an examination ofthe chemical ecology ofthe brown alga Halidrys siliquosa. Of eleven algal species tested, eight exhibited good antifouling activity, confirming marine algae as a potential source for the development ofnovel antifouling formulations. H. siliquosa crude extracts tested at concentrations equivalent to whole algal tissue inhibited bacterial growth, with bacteria isolated from the surface orH. siliquosa being less sensitive to the extracts compared to bacteria isolated from stones and open seawater. This suggested for the first time that bacteria associated with the surface of the seaweed had evolved some kind of resistance to the plant antimicrobial activity. Characterisation of the active components using NMR spectroscopy showed the activity to be largely associated with the presence of polyunsaturated fatty acids (PUFAs). Examination of purified fractions using GCIMS allowed identification and quantification of PUFAs 18:2, 18:4, 20:4 and 20:5. A separate study, determining minimum inhibitory concentrations of 18:2 and 20:4 against marine fouling bacteria indicated that both acids were present in sufficient concentrations in the plant to inhibit bacterial growth. The presence of PUPAs on the surface of the seaweed could not be demonstrated using a surface dip technique; however, this technique was originally developed for the extraction of non-polar metabolites only. This study suggests that PUFAs produced by H. siliquosa are potentially able to regulate biofouling by means of disrupting the early stage of biofilm development, i.e. bacterial colonisation. However, to confirm this hypothesis, the presence of PUFAs on the surface of the plant' still needs to be demonstrated.

The purpose of this study was to determine the effect of varying concentrations of geosmin on the growth of Bacillus cereus.

This study focuses on the seaweed biodiversity around the Antarctic Convergence in the South Atlantic. It integrates field work in the Falkland Islands and surrounding regions with algal culturing, molecular techniques, microscopy and morphological identification. Chapter 2 explores the diversity of seaweeds of the south-western Antarctic Peninsula which is poorly studied, contrasting with the substantial knowledge available for the northern parts of the Peninsula. A baseline seaweed species checklist for the southern Adelaide Island and northern Marguerite Bay region is presented here, combining data obtained during a small number of surveys in 1973-5 and a six week intensive diving-based field campaign in 2010-2011. Subantarctic and Antarctic regions remain little studied in their seaweed diversity. Chapter 3 is based upon field collections in the early 1970s and 2007-2013. It is supported by sequencing COI and reports new records of several macroalgal species and an oomycete. Chapter 4 revisits the enigmatic Subantarctic brown alga Cladochroa chnoosporiformis, which had been collected only on one occasion by Carl Skottsberg in 1907 from Port Philomel, West Falkland, resulting in its formal taxonomic description. Within the framework of this study, Cladochroa was rediscovered after 106 years at its type locality, confirming its existence and morphological features as described by Skottsberg. The recollection enabled molecular studies of its phylogenetic placement by DNA sequencing, suggesting that C. chnoosporiformis is conspecific with Utriculidium durvillei. In Chapter 5, DNA barcoding was applied to both seaweed tissue samples taken while preparing herbarium specimens during 2 expeditions to the Falkland Islands, and to live macroalgal isolates obtained from substratum samples using the Germling Emergence Method. In several cases, this enabled detection of previously unsequenced or undescribed taxa, respectively. The potential and challenges of applying DNA barcoding for cataloguing the biodiversity of remote bioregions such as the Falklands are discussed.

This study involved the development and evaluation of a number of biomonitoring techniques for use with members of the Ulvaceae, Enteromorpha intestinalis (L.) Link, and Viva iactuca (L.). The techniques included both previously established ones and those which required development. The two main procedures developed for these algae were the neutral red retention technique (making use of a vital stain) and the ion leakage Health Index (based upon electrolyte leakage). Following optimisation both were used to produce quantitative structure-activity relationships (QSARs) for a series of n-alcohols using log Kow as the physicochemical parameter. The resultant QSARs were statistically indistinguishable with line equations of -0.88 log Kow + 2.87 and -0.95 log Kow + 2.83 respectively, with r values of 0.98, suggesting that both reflect the same non-specific narcotic effect on membrane integrity. However the neutral red retention technique was less useful than the Health Index with low reproducibility and is therefore unsuitable for use as an environmental biomonitor. The effects of other compounds with specific modes of action were established using the ion leakage technique, the high toxicity of the antifouling compound tributyltin being reflected in the Health Index. Further development of the ion leakage technique involved inductively coupled - plasma mass spectrometry (ICP/MS) in the identification of ions lost during leakage. Synergistic toxicity was investigated exposing the algae to UV light and anthracene, simulating photo-induced toxicity. No photo-induced toxicity was observed although UV exposure did reduce the Health Index. An environmental assessment was carried out for algae from clean sites and organically and inorganically polluted sites, comparing the Health Index with other measures of health and bioaccumulation data. A long term study of a clean site showed the algal Health Index to be influenced by seasonally dependent physical parameters, but reflected reduced health in algae exposed environmentally to organic pollutants. Algae exposed to long term heavy metal pollution in the Fal Estuary had 'normal',. Health Indices, however chlorophyll fluorescence induction techniques did highlight a reduced photosynthetic efficiency in these algae. The ion leakage technique has potentially a wide application in field and laboratory based biomonitoring and direct toxicity studies. Chlorophyll fluorescence analysis was also shown to be useful although it requires further investigation and evaluation.

by Chow Fung-cheung, Judy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 106-117). / ACKNOWLEDGMENT --- p.i / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / LIST OF ABBREVIATIONS --- p.ix / LIST OF FIGURES AND TABLES --- p.xii / Chapter SECTION I- --- ISOLATION OF ACTIN GENE FRAGMENTS FROM CHLORELLA VULGARIS / Chapter CHAPTER 1: --- INTRODUCTION / Chapter 1.1 --- Functions of Actin --- p.1 / Chapter 1.1.1 --- Functions of Actin in Animals --- p.1 / Chapter 1.1.2 --- Functions of Actin in Plants --- p.2 / Chapter 1.1.2.1 --- In Lower Plants --- p.2 / Chapter 1.1.2.2 --- In Higher Plants --- p.2 / Chapter 1.2 --- Molecular Studies of Actin Gene Families in Plants --- p.4 / Chapter 1.2.1 --- Multigene Family --- p.4 / Chapter 1.2.2 --- Homologies Across Kingdom --- p.4 / Chapter 1.2.3 --- Homologies Within Kingdom --- p.5 / Chapter 1.2.4 --- Position of Intron --- p.5 / Chapter 1.2.5 --- Differential Expression of Actin Genes --- p.7 / Chapter 1.3 --- Objectives of Present Studies --- p.7 / Chapter CHAPTER 2: --- GENERAL TECHNIQUES / Chapter 2.1 --- Growth of Algal Strain --- p.9 / Chapter 2.2 --- Growth of Bacterial Strains --- p.10 / Chapter 2.3 --- Agarose Gel Electrophoresis --- p.10 / Chapter 2.4 --- Restriction Enzyme Digestion --- p.10 / Chapter 2.5 --- Recovery of DNA Fragments from Agarose Gel --- p.11 / Chapter 2.5.1 --- Glass Powder Elution of DNA --- p.11 / Chapter 2.5.2 --- Sephaglas´ёØ BandPrep Kit --- p.11 / Chapter 2.6 --- Large Scale Preparation of Plasmid by Using Magic´ёØ Maxipreps DNA Purification System --- p.12 / Chapter 2.7 --- Ligation --- p.13 / Chapter 2.8 --- Preparation of Competent Cells --- p.13 / Chapter 2.9 --- Transformation of Competent Cells --- p.14 / Chapter 2.10 --- Screening of Recombinant Plasmids --- p.14 / Chapter 2.11 --- Spun Column Techniques --- p.15 / Chapter CHAPTER 3: --- PCR-CLONING OF ACTIN GENE FRAGMENTS FROM CHLORELLA VULGARIS / Chapter 3.1 --- Introduction --- p.16 / Chapter 3.2 --- Materials and Methods --- p.16 / Chapter 3.2.1 --- Preparation of Genomic DNA from C. vulgaris --- p.16 / Chapter 3.2.2 --- Amplification of Actin Genomic Fragments by PCR --- p.17 / Chapter 3.2.3 --- Cloning of PCR Products --- p.17 / Chapter 3.2.4 --- Southern Blotting --- p.18 / Chapter 3.2.5 --- Radiolabeling of DNA Probe --- p.19 / Chapter 3.2.6 --- Prehybridization and Hybridization --- p.19 / Chapter 3.2.7 --- Sequencing Strategies --- p.20 / Chapter 3.2.7.1 --- Isolation of Template DNA --- p.20 / Chapter 3.2.7.2 --- Template Denaturation and Primer Annealing --- p.21 / Chapter 3.2.7.3 --- Labeling and Termination Reaction --- p.21 / Chapter 3.2.7.4 --- DNA Sequencing Electrophoresis --- p.21 / Chapter 3.3 --- Results and Discussion --- p.22 / Chapter CHAPTER 4: --- CLONING OF ACTIN COMPLEMENTARY DNA FRAGMENT FROM CHLORELLA VULGARIS / Chapter 4.1 --- Introduction --- p.31 / Chapter 4.2 --- Materials and Methods --- p.31 / Chapter 4.2.1 --- Preparation of RNA --- p.31 / Chapter 4.2.2 --- RT-PCR --- p.32 / Chapter 4.2.3 --- Southern Blotting and Hybridization --- p.32 / Chapter 4.2.4 --- Radiolabeling of DNA Probe --- p.32 / Chapter 4.2.5 --- Cloning of RT-PCR Product --- p.33 / Chapter 4.2.6 --- DNA Sequencing --- p.33 / Chapter 4.2.7 --- Sequence Analysis --- p.33 / Chapter 4.3 --- Results and Discussion --- p.34 / Chapter CHAPTER 5: --- SEQUENCE COMPARISON OF ACTIN GENES / Chapter 5.1 --- Introduction --- p.44 / Chapter 5.2 --- Materials and Methods --- p.44 / Chapter 5.3 --- Results and Discussion --- p.44 / Chapter 5.3.1 --- Nucleotide Sequence Analysis --- p.44 / Chapter 5.3.2 --- Analysis of the Predicted Amino Acid Sequence --- p.49 / Chapter 5.3.3 --- Codon Usage --- p.49 / Chapter 5.3.4 --- Intron-Exon Structure in Plant Actin Genes --- p.51 / Chapter 5.3.5 --- General Discussion --- p.53 / Chapter CHAPTER 6: --- ISOLATION OF FURTHER UPSTREAM SEQUENCE FOR ACTIN GENE (CAc18G) FROM CHLORELLA VULGARIS / Chapter 6.1 --- Introduction --- p.54 / Chapter 6.2 --- Materials and Methods --- p.54 / Chapter 6.2.1 --- Genomic Southern Analysis --- p.54 / Chapter 6.2.2 --- Preparation of Actin-Enriched DNA Fraction --- p.55 / Chapter 6.2.3 --- Ligation of Actin-Enriched Fragments with Specific DNA Cassette --- p.55 / Chapter 6.2.4 --- Amplification of Upstream Sequence by Nested PCR --- p.55 / Chapter 6.2.5 --- DNA Sequencing --- p.56 / Chapter 6.3 --- Results and Discussion --- p.57 / Chapter SECTION II - --- CONSTRUCTION OF TRANSGENIC CASSETTES FOR THE PRODUCTION OF BACILLUS TOXIN IN CHLORELLA VULGARIS / Chapter CHAPTER 1： --- INTRODUCTION / Chapter 1.1 --- Characteristics of Algae --- p.64 / Chapter 1.2 --- Biotechnology Potential of Algae --- p.66 / Chapter 1.3 --- Transgenic Algae --- p.68 / Chapter 1.3.1 --- Genes of Selection for Transformant --- p.70 / Chapter 1.3.1.1 --- Homologous Genes --- p.70 / Chapter 1.3.1.2 --- Heterologous Genes --- p.70 / Chapter 1.3.2 --- Transformation Technologies Used in Algae --- p.71 / Chapter 1.3.3 --- Expression of Transgenes in Algae --- p.73 / Chapter 1.4 --- Bacillus Toxin --- p.73 / Chapter 1.4.1 --- Bacillus thuringiensis --- p.73 / Chapter 1.4.2 --- Classification of Bacillus Toxin Genes (Cry Genes) --- p.74 / Chapter 1.4.2.1 --- Type I (CtyI Genes) --- p.74 / Chapter 1.4.2.2 --- Type II (CryII Genes) --- p.75 / Chapter 1.4.2.3 --- Type III (CryIII Genes) --- p.76 / Chapter 1.4.2.4 --- Type IV (CryIV Genes) --- p.76 / Chapter 1.4.3 --- Mode of Action of Insecticidal Effects --- p.77 / Chapter 1.5 --- Insect-Resistance Transgenic Plants --- p.78 / Chapter 1.5.1 --- Transgenic Plants Expressing Crystal Protein Gene --- p.79 / Chapter 1.5.2 --- Problems Encountered --- p.80 / Chapter 1.6 --- Aims of Present Studies --- p.80 / Chapter CHAPTER 2: --- CONSTRUCTION OF TRANSGENIC CASSETTES / Chapter 2.1 --- Introduction --- p.82 / Chapter 2.2 --- Materials and Methods --- p.82 / Chapter 2.2.1 --- Preparation of Plasmids Involved in the Construction of Master Cassette --- p.82 / Chapter 2.2.2 --- Construction of Master Cassette --- p.83 / Chapter 2.2.3 --- Multiple Cloning Site (MCS) of Master Cassette --- p.83 / Chapter 2.2.4 --- Preparation of Plating Cells --- p.85 / Chapter 2.2.5 --- Titering --- p.85 / Chapter 2.2.6 --- Preparation of Plate Lysate --- p.86 / Chapter 2.2.7 --- Amplification of Coding Region of CryIVC Gene --- p.86 / Chapter 2.2.8 --- Cloning of PCR Products --- p.87 / Chapter 2.2.9 --- Construction of Transgenic Cassette --- p.87 / Chapter 2.2.10 --- Confirmation of the Junction Sites --- p.89 / Chapter 2.2.11 --- Testing for the Sensitivity of Algae Towards Kanamycin --- p.90 / Chapter 2.3 --- Results and Discussion --- p.91 / Chapter CHAPTER 3: --- TRANSFORMATION OF ALGAE BY ELECTROPORATION / Chapter 3.1 --- Introduction --- p.97 / Chapter 3.2 --- Materials and Methods --- p.97 / Chapter 3.2.1 --- Harvesting of Algae --- p.97 / Chapter 3.2.2 --- Electroporation at Different Field Strength --- p.98 / Chapter 3.2.3 --- Plating Culture of Algal Cells --- p.98 / Chapter 3.2.4 --- Preparation of Plasmids for Electrop oration --- p.98 / Chapter 3.2.5 --- Transformation of Algae --- p.100 / Chapter 3.2.6 --- Study on the Uptake of DNA after Electrop oration --- p.100 / Chapter 3.2.6.1 --- Genomic DNA Preparation --- p.100 / Chapter 3.2.6.2 --- Analysis of DNA Uptake --- p.101 / Chapter 3.3 --- Results and Discussion --- p.101 / REFERENCES --- p.106 / APPENDIX --- p.118

Miu-kuen Kong. / Thesis (M. Ph.)--Chinese University of Hong Kong. / Bibliography: leaves 164-186.

Kong Sau Lai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 209-225). / Abstracts in English and Chinese. / Acknowledgements --- p.ii / Abstract --- p.iii / Contents --- p.vii / List of Tables --- p.xi / List of Figures --- p.xxiv / Chapter Chapter 1: --- General Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Study Site --- p.4 / Chapter 1.3 --- Study Material --- p.5 / Chapter 1.4 --- General Objectives --- p.6 / Chapter 1.5 --- Organization of the Thesis --- p.6 / Chapter Chapter 2: --- Seasonal Occurrence and Reproduction of Hypnea charoides in Ping Chau / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Materials and Methods --- p.12 / Chapter 2.2.1 --- Study sites --- p.12 / Chapter 2.2.2 --- Populations of Hypnea charoides --- p.13 / Chapter 2.2.3 --- Measurement of plant length --- p.14 / Chapter 2.2.4 --- Examination of reproductive structures --- p.14 / Chapter 2.2.5 --- Environmental parameters --- p.15 / Chapter 2.2.6 --- Statistical analysis --- p.15 / Chapter 2.3 --- Results --- p.16 / Chapter 2.3.1 --- Seasonal occurrence and growth of Hypnea charoides --- p.16 / Chapter 2.3.1.1 --- A Ma Wan populations --- p.16 / Chapter 2.3.1.2 --- Lung Lok Shui populations --- p.16 / Chapter 2.3.2 --- Reproductive seasonality --- p.17 / Chapter 2.3.2.1 --- A Ma Wan populations --- p.17 / Chapter 2.3.2.2 --- Lung Lok Shui populations --- p.19 / Chapter 2.3.3 --- Other observations --- p.19 / Chapter 2.3.4 --- Environmental parameters --- p.20 / Chapter 2.3.4.1 --- Photoperiod --- p.20 / Chapter 2.3.4.2 --- Seawater temperature --- p.20 / Chapter 2.3.4.3 --- Nutrient concentrations --- p.20 / Chapter 2.3.5 --- Statistical analysis --- p.21 / Chapter 2.3.5.1 --- A Ma Wan populations --- p.21 / Chapter 2.3.5.2 --- Lung Lok Shui populations --- p.22 / Chapter 2.4 --- Discussion --- p.23 / Chapter 2.4.1 --- Seasonal occurrence and growth of Hypnea charoides --- p.23 / Chapter 2.4.2 --- Reproductive seasonality --- p.27 / Chapter 2.4.3 --- Occurrence of cystocarps and tetrasporangia on the same thallus in Hypnea charoides --- p.34 / Chapter Chapter 3: --- Algal Recruitment on Artificial Clearings / Chapter 3.1 --- Introduction --- p.50 / Chapter 3.2 --- Materials and Methods --- p.52 / Chapter 3.2.1 --- Study site --- p.52 / Chapter 3.2.2 --- Clearing experiment --- p.53 / Chapter 3.2.3 --- Investigation on the clearing and control plots --- p.53 / Chapter 3.2.3.1 --- Species composition --- p.53 / Chapter 3.2.3.2 --- Percentage cover --- p.54 / Chapter 3.2.3.3 --- Species richness --- p.54 / Chapter 3.2.3.4 --- Species diversity --- p.55 / Chapter 3.2.4 --- Statistical analyses --- p.55 / Chapter 3.3 --- Results --- p.56 / Chapter 3.3.1 --- Species composition --- p.57 / Chapter 3.3.2 --- Percentage cover --- p.58 / Chapter 3.3.3 --- Species richness --- p.61 / Chapter 3.3.4 --- Species diversity --- p.65 / Chapter 3.4 --- Discussion --- p.69 / Chapter 3.4.1 --- Species composition and percentage cover --- p.70 / Chapter 3.4.2 --- Implications on algal succession --- p.76 / Chapter 3.4.3 --- Implications for Hypnea charoides --- p.79 / Chapter 3.4.4 --- Species richness and diversity --- p.82 / Chapter Chapter 4: --- Colonization of Early Algal Assemblages on Artificial Substrata / Chapter 4.1 --- Introduction --- p.121 / Chapter 4.2 --- Materials and Methods --- p.123 / Chapter 4.2.1 --- Study sites --- p.123 / Chapter 4.2.2 --- Experimental design --- p.124 / Chapter 4.2.3 --- Investigation for optimal sampling --- p.125 / Chapter 4.2.4 --- Examination of tiles / Chapter 4.2.4.1 --- Species composition --- p.127 / Chapter 4.2.4.2 --- Species richness --- p.127 / Chapter 4.2.4.3 --- Mean density --- p.127 / Chapter 4.2.4.4 --- Percentage cover of encrusting coralline algae --- p.128 / Chapter 4.2.4.5 --- Species diversity --- p.128 / Chapter 4.2.5 --- Statistical analyses --- p.128 / Chapter 4.3 --- Results --- p.129 / Chapter 4.3.1 --- Species composition --- p.130 / Chapter 4.3.2 --- A Ma Wan tiles --- p.130 / Chapter 4.3.2.1 --- Species richness --- p.130 / Chapter 4.3.2.2 --- Algal density --- p.131 / Chapter 4.3.2.3 --- Percentage cover of encrusting coralline algae --- p.133 / Chapter 4.3.2.4 --- Species diversity --- p.134 / Chapter 4.3.3 --- Lung Lok Shui tiles at -2 to -3 m CD - Biweekly-retrieved tiles --- p.135 / Chapter 4.3.3.1 --- Species richness --- p.135 / Chapter 4.3.3.2 --- Algal density --- p.136 / Chapter 4.3.3.3 --- Percentage cover of encrusting coralline algae --- p.136 / Chapter 4.3.3.4 --- Species diversity --- p.136 / Chapter 4.3.4 --- Lung Lok Shui tiles at 一2 to -3 m CD - Monthly-retrieved tiles --- p.137 / Chapter 4.3.5 --- Lung Lok Shui tiles at -1 m CD --- p.137 / Chapter 4.3.6 --- Permanently-placed tiles in A Ma Wan and Lung Lok Shui --- p.138 / Chapter 4.3.7 --- Presence of grazers and other organisms --- p.139 / Chapter 4.4 --- Discussion --- p.140 / Chapter Chapter 5: --- Seasonal Availability of Algal Propagules at Different Water Depths / Chapter 5.1 --- Introduction --- p.170 / Chapter 5.2 --- Materials and Methods --- p.171 / Chapter 5.2.1 --- Study sites and sample collection --- p.171 / Chapter 5.2.2 --- Experimental design --- p.173 / Chapter 5.2.3 --- Examination of tiles and statistical analyses --- p.174 / Chapter 5.3 --- Results --- p.174 / Chapter 5.3.1 --- Species composition --- p.174 / Chapter 5.3.2 --- Availability of algal propagules in A Ma Wan --- p.175 / Chapter 5.3.2.1 --- Species richness --- p.175 / Chapter 5.3.2.2 --- Frequency --- p.176 / Chapter 5.3.2.3 --- Species diversity --- p.177 / Chapter 5.3.3 --- Availability of algal propagules in Lung Lok Shui --- p.178 / Chapter 5.3.3.1 --- Species richness --- p.178 / Chapter 5.3.3.2 --- Frequency --- p.178 / Chapter 5.3.3.3 --- Species diversity --- p.179 / Chapter 5.3.4 --- Comparisons between A Ma Wan and Lung Lok Shui --- p.180 / Chapter 5.3.5 --- Physical parameters --- p.180 / Chapter 5.3.6 --- Correlation --- p.181 / Chapter 5.3.7 --- Other recruits - --- p.182 / Chapter 5.4 --- Discussion --- p.182 / Chapter Chapter 6: --- General Discussion --- p.197 / References --- p.205 / Appendix A --- p.222 / Appendix B --- p.270 / Appendix C --- p.278

No description available.

This dissertation investigate to determine the presence of biological nitrogen fixation in two reservoirs in the southwestern United States: Lake Arlington and Lake Ray Hubbard.

No description available.