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1
Lekan, Danelle Kara. "Influence of temperature, salinity and nutrients on growth and toxin of Karenia brevis clones". View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-2/r3/lekand/danellelekan.pdf.
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Bischoff-Bäsmann, Bettina. "Der Temperaturbedarf und Biogeographie mariner Makroalgen". Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 1992. http://catalog.hathitrust.org/api/volumes/oclc/54346279.html.
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Graham, Sylvia Lynne. "Growth and grazing of microzooplankton in response to the harmful alga Heterosigma akashiwo in prey mixtures /". Online version, 2008. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=305&CISOBOX=1&REC=8.
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Mabande, Edmund Rufaro. "Antimicrobial discovery from South African marine algae". University of the Western Cape, 2018. http://hdl.handle.net/11394/6592.
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>Magister Scientiae - MScAntimicrobials are chemical compounds that destroy or inhibit the growth of microorganisms. The majority of these antimicrobials are actually natural products or natural product derived with key examples being the pioneer antibiotics penicillin and cephalosporin. Antimicrobials are an extremely important class of therapeutic agents; however, the development of drug resistance and slow pace of new antibiotic discovery is one of the major health issues facing the world today. There is therefore a crucial need to discover and develop new antibacterial agents. In this study, the potential of marine algae as a source of new antibiotics was explored. Crude organic extracts and chromatographic fractions obtained from small-scale extraction of 17 different marine algae were used to prepare a pre-fractionated library that would be tested against several disease causing microorganisms. The activity of the pre-fractionated library and purified compounds was determined against a panel of drug resistant microorganisms namely Acinetobacter baumannii ATCCBAA®-1605™, Enterococcus faecalis ATCC® 51299™, Escherichia coli ATCC® 25922™, Staphylococcus aureus subsp. aureus ATCC® 33591™ and Candida albicans ATCC® 24433™. Finally, cytotoxicity tests of 50 selected library extracts and isolated compounds were done against two cell lines namely MCF-7 (breast cancer) and HEK-293 (kidney embryonic). Based on their antimicrobial activity and interesting chemical profiles, the seaweeds Plocamium sp. and Stypopodium multipartitum were selected for further study. Three new and unusual halogenated monoterpenes (4.16, 4.17 and 4.18) were isolated from Plocamium sp., and an unusual meroditerpenoid (5.8) was isolated from Stypopodium multipartitum. The metabolites were purified using preparative (silica gel) chromatography as well as semipreparative normal phase HPLC. The structures of purified compounds were determined from spectroscopic data, including nuclear magnetic resonance (NMR) spectroscopy. A small library of 153 fractions was generated from collections of South African marine algae. Pre-fractionated crude extracts showed excellent antimicrobial activity against all microbes but particularly against Staphylococcus aureus. The compounds were generally active against the Gram positive bacteria and the yeast. In conclusion, three antimicrobial halogenated monoterpenes and an unusual monoterpene were isolated from a Plocamium sp. and Stypopodium multipartitum respectively. Antimicrobial activity of crude fractions was excellent but that of isolated compounds was not as great as anticipated.
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Rufaro, Mabande Edmund. "Antimicrobial discovery from South African marine algae". University of the Western Cape, 2018. http://hdl.handle.net/11394/6529.
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>Magister Scientiae - MScAntimicrobials are chemical compounds that destroy or inhibit the growth of microorganisms. The majority of these antimicrobials are actually natural products or natural product derived with key examples being the pioneer antibiotics penicillin and cephalosporin. Antimicrobials are an extremely important class of therapeutic agents; however, the development of drug resistance and slow pace of new antibiotic discovery is one of the major health issues facing the world today. There is therefore a crucial need to discover and develop new antibacterial agents. In this study, the potential of marine algae as a source of new antibiotics was explored. Crude organic extracts and chromatographic fractions obtained from small-scale extraction of 17 different marine algae were used to prepare a pre-fractionated library that would be tested against several disease causing microorganisms. The activity of the pre-fractionated library and purified compounds was determined against a panel of drug resistant microorganisms namely Acinetobacter baumannii ATCCBAA®-1605™, Enterococcus faecalis ATCC® 51299™, Escherichia coli ATCC® 25922™, Staphylococcus aureus subsp. aureus ATCC® 33591™ and Candida albicans ATCC® 24433™. Finally, cytotoxicity tests of 50 selected library extracts and isolated compounds were done against two cell lines namely MCF-7 (breast cancer) and HEK-293 (kidney embryonic).
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Fong, Yin-shan. "Harmful Algal Blooms (HABs) in coastal waters and their management /". Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25436247.
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Lo, Shiu-hong. "Antibacterial activity of some marine planktonic algae in Hong Kong /". Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19667152.
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Nylund, Göran M. "Chemical mediation of fouling in seaweeds /". Göteborg : Göteborg University, Department of Marine Ecology, 2005. http://www.loc.gov/catdir/toc/fy0701/2006388585.html.
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Fletcher, Kyle. "Genetic investigations of oomycetes associated with marine algae". Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227933.
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This thesis aims to initially define the present knowledge of pathogens which infect algae, highlighting the potential economic significance of such pathogens, given the recent rise in algaculture. Focus is given to the oomycetes, a group of organisms which already contain several significant genera of plant (Phytophthora) and animal (Saprolegnia) pathogens, as well as Olpidiopsis; a genus reported to significantly impact algaculture in Asia. Subsequent chapters aim to genetically characterise stramenopiles (specifically oomycetes and hyphochytrids) associated with algae in two ways. Firstly known pathogens of algae, Olpidiopsis feldmanni and Anisolpidium rosenvingei are morphologically diagnosed by microscopy and genetically surveyed at phylogenetically significant loci. Further morphological information on these two pathogens is reported here expanding the current knowledge of these rarely reported organisms. Surprisingly, genetic evidence indicates that Anisolpidium, a uniflagellate genus, belongs to the biflagellate class Oomycota and not the closely related uniflagellate class Hyphochytriomycota, as previously suspected. Morphological and genetic features of these classes are contrasted to justify this molecular interpretation. These first two studies, along with the publically available sequences of algal pathogens are then used to design primers, which enable an oomycete-directed metagenomic survey of brown algae, allowing the investigation of what organisms are associated with these. At present the results of this survey are unreported. Finally a Eurychasma dicksonii transcriptome as well as genomic sequences of other stramenopiles are investigated for the presence of cadherin protein models. At present such models are automatically annotated and reported. This study is the first manual curation of the protein and defines a unique protein family which is presented by the oomycete genera Eurychasma, Pythium, Phytophthora and Albugo as well as the labyrinthulomycete Aurantiochytrium limanicum. The protein model is not reported from other sequenced oomycete genera or photosynthetic stramenopiles.
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Paul, Nicholas Andrew School of Biological Earth & Environmental Sciences UNSW. "The ecology of chemical defence in a filamentous marine red alga". Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2006. http://handle.unsw.edu.au/1959.4/24304.
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I investigated the ecological functions of halogenated secondary metabolites from the red alga Asparagopsis armata, their localisation in specialised cells and also their cost of production. A. armata produces large amounts of halogenated metabolites ( < 20 ??g / mg dry weight) that are sequestered in gland cells, as was demonstrated with light, epifluorescence and transmission electron microscopy. Cellular structures were identified that likely assist the release of metabolites from the gland cells to the algal surface. The halogenated metabolites of A. armata have multiple ecological roles, functioning as both inhibitors of bacterial fouling and as herbivore deterrents. Their activity against bacteria and herbivores was measured by a novel test in which the metabolites were manipulated in A. armata by omitting bromide ions from the culture media. This technique prevented the production of halogenated metabolites, but did not impact on other aspects of algal biology. Algae lacking halogenated metabolites (bromide [-] algae) had higher densities of epiphytic bacteria than those that continued to produce metabolites (bromide [+] algae). Bioassays with pure compounds against individual bacterial isolates further supported an inhibitory role for the halogenated metabolites against epiphytic bacteria, and also indicated an affect on bacterial community structure as well as abundance. Bromide (+) A. armata produced halogenated metabolites that also deterred feeding by two herbivores (an amphipod and an abalone), but not a third (an opisthobranch mollusc). A novel outcome from these feeding assays was the demonstration of a relationship between herbivore size and consumption of the chemically defended A. armata by the abalone Haliotis rubra. In addition to the fitness benefits gained from chemical defence, there were also costs for allocating resources to secondary metabolites. These costs were only detected under limiting light resources, consistent with predictions of the plant defence models. The integration of chemical analyses and cellular measures of chemical defence proved essential in elucidating resource allocation to chemical defence in the filamentous stage of A. armata. This thesis highlights that the simple relationships between growth and defence in filamentous algae can provide an excellent model for studies of the ecology and evolution of chemical defences in marine algae.
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McGee, Dorien Kymberly. "Morphologic comparisons of shallow and deepwater benthic marine diatoms of Onslow Bay, North Carolina /". Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/mcgeed/dorienmcgee.pdf.
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Levine, Michael R. Muller-Parker Gisèle. "The effects of season and microhabitat on the distribution and nutritional contributions of two algal symbionts in the intertidal anemone Anthopleura xanthogrammica /". Online version, 2010. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=335&CISOBOX=1&REC=11.
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Carter, Alan Robert. "Studies on the biology of the economic marine red alga Gelidium pristoides (Turner) Kuetzing (Gelidiales : Rhodophyta)". Thesis, Rhodes University, 1987. http://hdl.handle.net/10962/d1004774.
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Various aspects of the biology of the intertidal agarophyte, Gelidium pristoides, were investigated, with the aim of providing information that would assist in formulating a management policy for this economic seaweed resource. G.pristoides occurs as tufts comprising as many as 40 individual plants, representing all three conspicuous life history stages, that are linked by the intertwining of their basal creeping axes. Individual plants consist of a system of branched creeping axes, which is largely responsible for colonizing surrounding substrata, from which one or more erect flattened fronds arise. These erect fronds may reach a height of 15 cm, and are irregularly bipinnately branched. Internal vegetative anatomy is generally typical of the genus. Morphological variation in mature plants is limited to increased plant height and branch density during the summer season. A dorso-ventrally flattened creeping habit was seen during early recruitment on flat rock surfaces and limpet shells within grazer exclusion plots, which developed into typical erect plants. Although there is a close taxonomic affinity between G.pristoides and the low-growing Gelidium turf, which occurs on wave-cut platforms in the eastern Cape (both produce bispores), the turf appears to represent a genetically divergent ecotype of the typical G.pristoides habit. In the light of present observations, it is suggested that the recent inclusion of G.pristoides in the new Onikusa genus should be questioned. Reproduction in G.pristoides is typical of the genus, except for the production of bispores, instead of tetraspores, in the sporophyte generation. The smaller nuclei in the binucleate bispores, in comparison to carpospores, suggested they are the product of normal meiosis (meiospores). This was confi rmed by chromosome counts of germl i ngs deri ved from bispores (n = 13-17) and carpospores (2n = 28-33). Throughout the geographical range of the seaweed, the bisporophyte generation is dominant over the combined male and female gametophyte generati on by a ratio of about 3 : 1. This imbalance may be due to bispores. G.pristoides a greater germination success of carpospores over plants are fertile throughout the year, while at Port Alfred there is no apparent seasonality in spore release. Growth of carpospore and bispore germlings is similar under various temperature treatments in culture. Optimum temperatures for growth were from 15-23°C, which corresponds with the sea temperatures experienced within the geographical range of the species . At Port Alfred, growth (linear frond elongation) and standing crop levels were maximal during summer . Ory weight levels were significantly inversely related to both growth and ash levels. Agar contents (% of dry weight) were generally greater in summer (48% ) than in winter (30%), and were inversely correlated with thallus nitrogen levels. Agar contents of distal plant halves were higher (8-15%) than in proximal halves. Regrowth of G.pristoides to original biomass or standing crop levels after harvesting, is similar for plucking and shearing at different times of the year. Regrowth is more rapid after spring and summer harvests (2-3 months) than after winter harvests (4-5 months). During the summer season, harvesting at monthly intervals showed significantly greater total yields, and production rates (e.g . 3.13 g. dry wt. / m2 / day for plucking) than under 3-monthly intervals (1.42 g. dry wt. / m2 / day for plucking). In contrast, average yields per harvest were Significantly greater when recovery period was longer (e.g. 3 months). Quadrats that were completely denuded failed to recover after a year, while regrowth was also retarded with increased elevation on the shore. Agar contents did not differ Significantly between plucked (38%) and sheared (42%) plant material. G.pristoides is distributed from about 0 . 2-0.75 m above MLWS, with a reduction in stature and frequency corresponding to increased elevation on the shore. Frond elongation rates, germling survival and recruitment within grazer-exclusion plots, is retarded with increased elevation level. Plants transplanted above the normal vertical range of the seaweed became severely bleached and died, while plants transplanted below the normal range of the seaweed (sub littoral fringe) senesced due to overgrowth by the epiphytic encrusting coralline, Polyporolithon patena (Hook . et Harv . ) Mason . G.pristoides recrui t ment in the sublittoral fri nge was enhanced with the exclusion of grazers . However, successful recruits were displaced due to smothering by articulated corallines (e.g. Corallina sp. and Jania sp. ) . G.pristoides is largely restricted to cracks and crevices in the rock, and also occurs on a large proportion of the available shells of the limpet Patella oculus Born., and to a lesser extent, shells of the barnacle Tetraclita serrata. G.pristoides recruitment was significantly enhanced by the exclusion of grazers (using toxic antifouling paint barriers). G.pristoides recruitment within the exclusion plots was significantly greater on artificially attached limpet shells (almost 100% cover) than on rock surfaces (20-30% cover), which occurred largely within cracks and crevies in the rocky substratum. ly attached to limpet G.pristoides plants are significantly more strongand barnacle shells than to rock and epilithic encrusting corallines (Lithothamnion sp.). Removal of G.pristoides from limpet shells revealed pits of a uniform size in the surface of the shells, into which the rhizoidal attachment organs of the seaweed penetrate. It is concluded that the horizontal distribution of G.pristoides is largely controlled by grazers (and "escapes" from grazing) and resistance to dislodgement by wave action. Based on present results, and considering some of the socio-economic factors associated with the Gelidium industry in South Africa, suggestions are made concerning the management and long-term maintenance of G.pristoides resources in the eastern Cape.
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Pande, Nilesh Navalkishor. "Interactions between the toxic alga, Alexandrium fundyense, and its bacterial associates stimulation, inhibition, and specificity /". Restricted access (UM), 2008. http://libraries.maine.edu/gateway/oroauth.asp?file=orono/etheses/37803141.pdf.
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These (Ph.D.)--University of Massachuesetts Lowell, 2008.Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (leaves 55-66). Also issued in print.
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Raccagni, Monica. "Organic nitrogen uptake by marine algae : consequences for marine ecosystem functioning and biodiversity". Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/12816.
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Dissolved organic nitrogen (DON) represents a major pool of fixed, reactive nitrogen in marine systems. It is now recognized that this pool can support primary production and the ability of some algal species to exploit DON compounds as sources of Nitrogen (N) may indicate that specific DON components can exert selective pressure on the composition of the phytoplankton community. In this study the ability of monocultures of ecologically-relevant algal species from the English Channel (Emiliania huxleyi, Micromonas pusilla, Alexandrium minutum and Chaetoceros peruvianus) to grow with DON as the only N source was examined using different artificial media. Among the two tested artificial seawater recipes, Aquil* was preferred as it contained lower micronutrient concentrations, and gave better growth results for all used species. In order to constrain the DON uptake to algae alone, a method for bacterial removal was tested using antibiotic additions. Both Slocombe antibiotic mixture (Cefotaxime-Carbenicillin-Kanamycin-AugmentinTM) and Penicillin-Streptomycin-Neomycin used were effective and not toxic to the algae. Incubation with the antibiotic up to 48 hours and a transfer period into antibiotic-free medium after 72 hours proved to be effective. However, the treatment removed bacteria in A. minutum cultures only; further treatment would be required for the other species to be cultured axenically. The ability to use DON was tested for the above mentioned species using the amino acid L-Arginine (ARG) as the sole N source, and growth was compared with nitrate-containing cultures of the same species. All the selected species grew in both NOᴈ‾ and in ARG, reaching lower final densities when incubated with ARG, although these were not significant. This study has shown that E. huxleyi, A. minutum, M. pusilla and C. peruvianus can grow on organic N, either by direct or indirect uptake, and develop comparable biomasses to species using inorganic N. Both C. peruvianus and M. pusilla cultures contained dissolved ammonium at the end of the experimental period, indicating potential indirect use by the algae of organic N converted to inorganic N by bacteria. A. minutum grew in the presence of ARG along with the cosmopolitan E. huxleyi; N-demand estimates, based on the molar concentration of N-ARG consumed, correlated with the final cell density, indicating that the species did not develop on inorganic N produced from ARG mineralisation, but directly on the ON substrate. Since A. minimum has been linked to harmful algal blooms, and E. huxleyi contributes significantly to oceanic CaCOᴈ deposition, their ability to utilise DON has environmental consequences in addition to the oceanic N-budget. Climate change scenarios predict both episodic conditions of elevated rainfall and extended periods of dry conditions leading to variable riverine inputs to coastal areas, altered nitrogen to phosphorus (N:P) ratios, and changes in the inorganic to organic balance of the nutrient pools. Organic N can constitute up to 69 % of the total N pools, respectively, making it crucial, to understand the cycling of this fraction in coastal waters, and how changes in the composition of nutrient pools could impact on marine ecosystem function and health.
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Carter, Anne Margaret. "Studies on the bioactivities of selected Eastern Cape seaweeds". Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1004093.
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In studies on the bioactivities of selected eastern Cape seaweeds, a suitable extraction solvent, namely methanol was used. The antimicrobial, antineoplastic and antiviral activities were investigated, and a seasonal comparison of antimicrobial activities as well as a scanning electron microscopic study were included. A number of algae were found to display significantly high antibacterial activities, of these, the two red algae Plocamium corallorhiza and Laurencia glomerata and the two brown algae Zonaria subarticulata and Ecklonia biruncinata showed the most potent broad spectrum antibacterial activity. L.glomerata and E.biruncinata were active against all five test bacteria, but were inactive against the yeast Candida albicans. C.albicans was the most resistant organism tested,~with only Peyssonelia capensis, f-corallorhiza and Ulva rigida inhibiting its growth. Of the 17 seaweeds tested, none showed any clear seasonal changes in antimicrobial activity. The microorganisms however did vary in their susceptibility to treatment. Staphylococcus aureus and the Micrococcus species were the most susceptible to treatment by the algal extracts, with the Gram positive endospore former, Bacillus subtilis and the two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa showing more resistance to treatment. C.albicans however was the most resistant organism. In the antineoplastic studies, the brown algae Z.subarticulata, E.biruncinata and Sargassum heterophyllum showed potent activity against both the normal, LLCMK, and cancerous, mouse melanoma-3S0 cells, reducing cell growth in each case. The green algae showed potent activity against the cancerous cells, lowering growth to 30% that of the normal cells. Normal cell growth was unaffected or was stimulated by the presence of these algal extracts. The red algae showed no antineoplastic activity. Representatives of each of the red, brown and green algae were used in the brine shrimp (Artemia salina) cytotoxicity study. None of the algae showed any toxicity towards the brine shrimp. In the antiviral studies against Polio Type 1, strain L-Sa, a reduction in virus infectivity was used as an indication of the presence of antiviral properties in the seaweeds tested. This was done by comparing the virus titres of algal-treated cells with those of untreated cells. Six of the algae tested displayed antiviral activity, these were the two Rhodophyceae Hypnea spicifera and L.glomerata, the two Phaeophyceae Dictyopteris macrocarpa and Dictyota naevosa, and the two Chlorophyceae U.rigida and Halimeda cuneata. Of these, D.naevosa showed particularly strong activity, recording a log reduction in virus titre of 4.
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Zhang, Fangzhu. "Harmful algae from container ship ballast water taken from the open ocean and from Oakland, California (May, 1996 to April, 1997) /". Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19589049.
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Turner, David J. "Effects of sedimentation on the structure of a phaeophycean dominated macroalgal community /". Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09pht944.pdf.
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Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2005?"July 2004" Includes bibliographical references (leaves 150-172). Also available electronically.
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Nguyen, Thi Hong Minh, i Van Hanh Vu. "Bioethanol production from marine algae biomass: prospect and troubles". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99282.
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The increase of petroleum cost as well as global warming and climate change result in investigation to discover new renewable energy resources. Bioenergy is one of the most important sources that is concerning the scientists and industrial sector. Although bioethanol had to be known as one of the most important renewable energy sources in order to reduce greenhouse gases and global warming, there is a limited number of publications reporting on them. In this review, a brief overview is offered about bioethanol production from algae. It can be given a deeper insight in dificulties and promising potential of bioethanol from algaeSự gia tăng giá nhiên liệu hóa thạch cùng với cảnh báo toàn cầu về biến đổi khí hậu hướng đến việc nghiên cứu tìm ra những nguồn năng lượng có thể tái tạo. Năng lượng sinh học là một trong những nguồn quan trọng được các nhà khoa học và doanh nghiệp quan tâm. Mặc dù ethanol sinh học đã được biết đến như là một trong những dạng năng lượng tái tạo quan trọng nhất để giảm thiểu các khí nhà kính và cảnh báo toàn cầu, nhưng chỉ có một số ít bài báo về nó. Trong bài tổng quan này, chúng tôi giới thiệu vắn tắt việc sản xuất ethanol sinh học từ tảo. Nó đưa ra cái nhìn sâu hơn về những khó khăn và tiềm năng hứa hẹn của sản xuất ethanol sinh học từ tảo
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Djabayan-Djibeyan, Pablo. "A comparison of lectins in green Venezuelan marine algae". Thesis, University of Portsmouth, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343338.
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Tsang, Angela Ka Yen. "The uptake of arsenicals by the marine algae Isochrysis galbana and Dunaliella tertiolecta". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29198.
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Two marine algae, Isochrysis galbana and Dunaliella tertiolecta, were grown in the presence of arsenate, arsenite, monomethylarsonate (MMA), and dimethylarsinate (DMA). Cell growth was monitored by using in vivo fluorescence and cell density measurements. The effects of different levels of arsenicals on the arsenic uptake were examined using Hydride Generation Atomic Absorption (HGAA) Spectrometry and Graphite Furnace Atomic Absorption (GFAA) Spectrometry. The spin-echo ¹H NMR spectra of these algae are reported.
Significant arsenic uptake and incorporation occurred when both algae were subjected to elevated levels of arsenicals. I. galbana was most affected by arsenite at the range of concentrations tested (2 - 8 ppm). Total incorporation is also the highest in this medium. The alga seems to be able to adapt to high arsenate concentrations.
D. tertiolecta was most affected by elevated levels of arsenate (10.7 ppm). Water soluble extracts of algal cells grown in this medium contain at least four arsenicals which possibly include arsenate and arsenite.
Growth of both algae was not affected by DMA at the levels examined. Growth enhancement is observed in all MMA treated cultures. Arsenic speciation of the residual media showed that both algae can reduce arsenate to arsenite.Science, Faculty of
Chemistry, Department of
Graduate
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Yang, Zhenbo. "Harmful algal blooms in selected Hong Kong coastal waters". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22534374.
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Wilson, William Hector. "Characterisation of viruses infecting marine phytoplankton". Thesis, University of Warwick, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283512.
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Craggs, Rupert Justin. "Wastewater nutrient removal by marine microalgae". Thesis, University of St Andrews, 1994. http://hdl.handle.net/10023/14217.
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Although, microalgal wastewater treatment systems represent an efficient and economical alternative to conventional processes, the use of marine microalgae to remove nutrients from wastewaters has not been extensively researched and few studies have been made in temperate and high latitude areas, where climate may limit treatment. In this study, 102 marine microalgal species, including 66 local endemic isolates from St Andrews Bay, Fife, Scotland, were screened under batch and continuous culture. Species were selected for their ability to remove high concentrations of ammonium and ortho-phosphate from primary treated sewage (diluted 1:1 with sterile seawater) while remaining dominant in culture. Abiotic removal of ammonium and ortho-phosphate at high pH was found to be low from saline media, indicating that much of the nutrient removal from the seawater:wastewater mixture was by algal uptake. Many of the best-treating species grew over a wide range of temperature (10-25 °C), and their growth was not inhibited by the low salinity of the 1:1 diluted wastewater. Seven best-treating species continuously removed >80 % ammonium and >70% ortho-phosphate when cultured in 20 litre mini-ponds (modelled on high-rate ponds) under ambient summer conditions over two weeks. These were all endemic isolates including six bacillariophyceaen isolates (of which three were strains of Phaeodactylum tricornutum), and a species of the cyanophyceaen Oscillatoria. Two isolates (Oscillatoria and an unidentified bacillariophyceaen SA91B33) with adherent properties, continuously removed 100 % of both ammonium and ortho-phosphate when tested in a corrugated raceway designed to provide a large surface area for attachment. Preliminary experiments further showed the best-treating species to be capable of removing nutrients from eel aquaculture effluent. The abilities of marine microalgal species to remove high concentrations of nutrients, remain in unialgal culture and grow over a range of environmental conditions are indicative of their potential for use in wastewater treatment systems in temperate areas.
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Jong, Yde Sijbrand Diederick Maria de. "Systematic, phylogenetic and biogeographic studies of Atlantic seaweeds". [Leiden] The Netherlands : Rijksherbarium/Hortus Botanicus, Leiden University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/40701628.html.
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Madikiza, Liwalam Onwabile. "The role of grazers and basal sustrate cover in the control of intertidal algal distribution". Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&.
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Turner, David John. "Effects of sedimentation on the structure of a phaeophycean dominated macroalgal community". Connect to this title online, 2004. http://hdl.handle.net/2440/37702.
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Macroalgae are abundant on shallow temperate reef environments, often forming complex communities that comprise several strata. In southern Australia, these assemblages are dominated by large canopy forming taxa from the Orders Laminariales and Fucales. The presence of subtidal fucoid macroalgae differentiates these communities from that elsewhere, and emphasises the need for local studies rather than relying on generalisations made elsewhere. Like most natural systems, temperate reefs are often threatened by human activity with degradation reported from many locations in close proximity to urban settlements. The work presented in this thesis involves an examination of the temporal and spatial variability in the structure of macroalgal communities from reefs along the Adelaide (South Australia) metropolitan coast. The work looked specifically at the effects of a dispersed sediment plume, resulting from the 1997 beach sand-replenishment dredging program, on shallow sub-tidal reef systems. An examination of the structure of canopy forming phaeophycean macroalgae in Gulf St Vincent (South Australia), noted large amounts of both spatial and temporal heterogeneity. Notwithstanding, this variation was not random, but demonstrated considerable structure that could be linked to a number of important underlying processes. In particular, macroalgal assemblages appeared as a mosaic of patches, each of which comprised a high-density state clearly dominated by a single genus (Cystophora, Sargassum, or Ecklonia), or alternatively a lower density mixed assemblage (Variable Low Abundance, VLA). Macroalgal community structure appeared to be driven by biotic interactions at small scales (metres), such that patches comprised of different species of algae in high density states rarely abutted one another. Instead, VLA assemblages frequently formed a buffer being situated between these mono generic patches. In terms of successional processes, the high-density states appeared to be relatively stable whereas the VLA state, at least in some systems, was transitory. This finding was supported by the absence of intermediary high- density states (e.g. a mix of Cystophora and Ecklonia) implying that state changes must occur via the VLA state following some form of disturbance. Larger scale patterns appeared to be driven by environmental variation, with factors such as wave exposure influencing habitat suitability for individual species and thereby affecting community composition. These phenomena were examined in terms of life history strategies that tend to promote stability, and which are common in late successional taxa. The importance of properties enhancing stability and the role of disturbance was investigated experimentally using a dispersed sediment plume, which entirely engulfed two reefs, as a pulse impact. This disturbance was of particular relevance given that degradation of macroalgal communities in close proximity to the City of Adelaide has been, at least in part, attributed to the effects of elevated levels of sediment. Follow up surveys revealed that the sedimentation from the plume had primarily affected newly recruiting individuals, with few juveniles surviving to one year of age. Over the following few years, the effect of this recruitment failure cascaded into the adult stand. In broader terms, unfavourable climatic conditions prior to the start of the study, including a particularly severe El Nino event, had a widespread effect on local assemblages, causing high levels of both adult and juvenile mortality. As such, at the commencement of the study, macroalgal communities across the study area were in the process of recovery. This was observed at control sites over the duration of the study. In contrast, recruitment failure at the sediment-affected sites retarded the recovery process, exacerbating the problems associated with prior unfavourable climatic events and leaving them in a degraded state. This study demonstrated that macroalgal assemblages are equipped (under natural conditions) to handle 'normal' environmental fluctuations (such as inter-annual variability). However, the additional stress associated with certain anthropogenic impacts has the potential to push them over the limit, causing degradation. The loss of canopy macroalgae reduces the structural complexity of the system, leading to a concomitant reduction in their ability to recover. As such, these findings are of particular relevance to those charged with the responsibility for managing near-shore marine environments. The plume was created accidentally during a dredging operation for beach sand replenishment of Adelaide's eroding shoreline.Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2004.
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Plumb, Jeremy. "Population dynamics and endophytic flora of Chondrus crispus (Rhodophyta) : a temporal study". Thesis, Bath Spa University, 1999. http://researchspace.bathspa.ac.uk/1584/.
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A temporal long-term study of the population structure and dynamics of the red alga Chondrus crispus at Lilstock, Somerset (Bristol Channel), the British Isles, and an investigation of its associated green and brown endophytic algal flora were undertaken from January 1994 to September 1996. The population of C. crispus was composed of plants which consisted of a basal holdfast from which arose numerous fronds in varying stages of development, with or without reproductive fronds (cystocarps or tetrasporangial sori). Plants were found with only gametophyte (haploid) or tetrasporophyte (diploid) fronds, whereas other plants described as mixed clumps consisted of gametophyte and tetrasporophyte fronds associated with the same basal disc. New plants entered the population and others were lost throughout the study. Individual plant longevity ranged from <46 days to >927 days. The monthly gametophyteitetrasporophyte ratio did not significantly deviate from 1:1, and within the population there was a stable long-lived core of plants, with a gametophyte:tetrasporophyte ratio of 1:1. Gametophyte plants with cystocarps had a significantly greater dry mass and contained a significantly greater number of fronds than tetrasporophyte plants with sori. Significantly higher numbers of tetrasporophytes had reproductive structures (sori) than gametophyte plants (cystocarps) during summer months (namely May, June and July). Both recruitment from spores and frond regeneration from remnant basal discs played an important role in maintaining the population structure. At least 6 green algal taxa including Acrochaete heteroclada, A. operculata, A. repens, A. viridis, Enteromorpha sp(p) and Pseudoendoclonium sp., and at least one brown algal taxon assigned to the genus Streblonema were found in association with gametophyte and tetrasporophyte C. crispus plants with cystocarps and sori, respectively. Spatial distribution of these algae within host tissues ranged from epiphytic through epiendophytic to endophytic. Of the C. crispus plants collected the frequency of plants infected with endophytic algae was reported to reach 95%. Infection by brown algae was rarely found without an associated green algal infection. It is hypothesised that a self-purging natural purification process of infected C. crispus fronds helps rid the plants and population of diseased fronds. It is suggested that it is primarily through the retention of the basal discs that C. crispus is an ecologically successful species.
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Truxal, Laura T. "Characterization of novel compounds isolated from Karenia brevis cultures". View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-3/rp/truxall/lauratruxal.pdf.
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Kune, Daniel. "Extraction and purification of polyunsaturated fatty acids from marine algae". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406588.
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Lo, Shiu-hong, i 羅兆康. "Antibacterial activity of some marine planktonic algae in Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B3121339X.
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Linnane, Kevin. "The effects of heavy metals on marine algae - animal interactions". Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440576.
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Scott, Caroline Daphne. "The role of blue-green algae as marine fouling organisms". Thesis, University of Portsmouth, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282555.
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Young, John J. "Experimental harvests of macroalgae along the Oregon coast with an analysis of associated epiphytic diatom communities". Thesis, Thesis (M.S.)--University of Oregon, 2003, 2003. http://hdl.handle.net/1794/10076.
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Goodsell, Paris Justine. "Consequences of disturbance for subtidal floral and faunal diversity /". Title page, abstract and table of contents only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phg6555.pdf.
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Ruchonnet, Diane Astrid. "The chemical ecology and antibacterial activity of the brown alga Halidrys siliquosa and other Scottish seaweeds". Thesis, University of Aberdeen, 2007. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186834.
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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.
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Mystikou, Alexandra. "Seaweed biodiversity around the Antarctic Convergence in the South Atlantic". Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227597.
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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.
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Crawley, Karen Ruth. "Detached macrophyte accumulations in surf zones: Significance of macrophyte type and volume in supporting secondary production". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2006. https://ro.ecu.edu.au/theses/1744.
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Detached macrophytes (sea grass and macroalgae) are transported from more offshore areas and accumulate in large volumes in surf zones, where they are commonly called wrack. In coastal regions in other parts of the world, wrack transported from one habitat to a second habitat can be considered as a "spatial subsidy" for the recipient habitat with significant consequences for community dynamics and food webs. The primary aim of this study was to determine the significance of the different components of wrack (i.e. sea grass and brown, red and green algae) as a direct and indirect food source and habitat for invertebrates and fish in surf zones of south-western Australia. The importance of different volumes of surf zone wrack to determining fish abundance and composition was also investigated. These aims were achieved by examining the food and habitat preference of invertebrates and the habitat preference of fish through laboratory trials and field experiments. Gut content analysis was used to examine the importance of wrack-associated invertebrates as a food source for fish, while stable isotope analysis (carbon, nitrogen and sulfur) and lipid analysis (lipid class and fatty acid composition) were conducted on macrophytes, amphipods and fish to determine the source of nutrients and energy. The composition of surf zone wrack in the region comprises large quantities of seagrass, then brown and red algae, with negligible quantities of green algae. Allorchestes compressa, the dominant macroinvertebrate in surf zone wrack, showed a preference for consuming brown algae over other macrophyte types. Similarly, stable isotope analysis from some locations and fatty acid analyses indicated that A. compressa assimilates nutrients predominantly from brown algae. The influence of brown algae on secondary production extends to second-order consumers. Allorchestes compressa was the major prey of juveniles of the cobbler Cnidoglanis macrocephalus and the sea trumpeter Pelsartia humeralis, the main fish species in surf zone wrack accumulations in the region. Detached brown algae therefore contributes most to the detached macrophyte - amphipod - fish trophic pathway in the surf zones, and thus drives secondary production in these regions and provides a crucial link between coastal ecosystems. Detached macrophytes also provide an important, but transient, habitat for invertebrates and fish in south-western Australia. Under laboratory conditions, Allorchestes compressa showed a strong preference for inhabiting seagrasses over macroalgae, iii however in situ caging experiments showed that A. compressa has a strong preference for brown algae, red algae or a mixture of macrophytes, but tended to avoid seagrass. Therefore, A. compressa showed a clear preference for different types of detached macrophytes as a habitat, with seagrass ranking below other types of macrophyte under field conditions. In contrast, neither Cnidoglanis macrocephalus or Pelsartia humeralis showed a preference for inhabiting different types of detached macrophytes as a habitat, but showed a strong positive influence by increasing volumes of wrack The species composition, densities and biomass of fish, which were dominated by juveniles, were strongly influenced by increasing volume of wrack in surf zones of south-western Australia. This study has shown that both the type and volume of detached macrophytes transported from more offshore regions subsidizes consumers and plays a crucial role in supporting secondary production in less productive surf-zone habitats of south-western Australia. The removal of large amounts of wrack from nearshore areas could have a detrimental impact on the biodiversity or abundance of macroinvertebrate and fish populations, which rely on wrack for food and shelter.
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Steyn, Paul-Pierre. "The ecophysiology of Gelidium Pristoides (Turner) Kuetzing : towards commercial cultivation". Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1117.
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The ecophysiology of the red alga Gelidium pristoides (Turner) Kuetzing was investigated in an effort to establish a technique for commercial cultivation. The seaweed is of commercial importance in South Africa where it is harvested from the intertidal zone rocky shores along the coast. It is dried and exported abroad for the extraction of agar. Yields and quality could be improved by cultivation in commercial systems. However, attempts at growing the seaweed in experimental systems have all ended in failure. This study aimed to describe the conditions in which the seaweed grows naturally; and investigate its physiological response to selected physical conditions in the laboratory in order to determine suitable conditions for mariculture. Ecological studies showed that G. pristoides grew above the spring low tide water level. The upper limit of the seaweed’s vertical distribution range, as well as its abundance, was largely dependent on wave exposure. The zone normally inhabited by G. pristoides was dominated by coralline turf in sheltered areas, while the abundance of G. pristoides increased towards more exposed rocky shore sites. The seaweed occurred among species such as Pattelid limpets and barnacles, but was usually the dominant macroalga in this zone, with coralline turf and encrusting algae being the only others. Physical conditions in the part of the intertidal zone inhabited by G. pristoides were highly variable. During low tide temperatures could vary by as much as 10°C within the three hours between tidal inundation of the seaweed population, while salinity varied by up to 9 ppt, and light intensity by as much as 800 μmol m-2 s-1. During these exposure periods the seaweed suffered up to 20% moisture loss. Laboratory experiments on the seaweed’s response to these conditions indicated that it was well adapted to such fluctuations. It had a broad salinity (20 and 40 ppt), and temperature tolerance range (18 to 24°C), with an o ptimum of temperature of 21°C for photosynthesis, while there was no difference in the photosynthetic rate of the alga within the 20 to 40 ppt salinity range. The alga had a low saturating irradiance (ca. 45 – 80 μmol m-2 s-1) equipping it well for photosynthesis in turbulent environments, with high light attenuation, but poorly to unattenuated light conditions. Exposure resulted in an initial increase in photosynthetic rate followed by a gradual decrease thereafter. pH drift experiments showed that low seawater pH, and associated increased carbon dioxide availability, resulted in an increase in photosynthetic rate. This response suggests that the seaweed has a high affinity for carbon dioxide, while the reduction in photosynthetic rate in response to bicarbonate use inhibition indicates that it also has the capacity for bicarbonate use. The high affinity of Gelidium pristoides for carbon dioxide as an inorganic carbon source appears to be the primary reason for the low abundance of the alga on sheltered rocky shore areas, and also explains the failure of the alga to grow in tank or open-water mariculture systems. Exposed rocky shores have experience heavy wave action, and the resultant aeration and mixing of nearshore waters increases the availability of carbon dioxide, which is considered a limiting resource. The absence of such mixing and aeration at sheltered site makes this less suitable habitat for G. pristoides. Periodic exposure also makes high levels of atmospheric carbon dioxide available from which the seaweed benefits. The traditional mariculture systems in which attempts have been made to cultivate the seaweed failed to satisfy either of the above conditions.
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Kennish, Robin. "Seasonal patterns of algal availability, influences on diet selection and fitness of the tropical crab grapsus albolineatus". Thesis, Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17591533.
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Zhang, Fangzhu, i 張芳珠. "Harmful algae from container ship ballast water taken from the open ocean and from Oakland, California (May, 1996 to April, 1997)". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31220277.
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Connolly, Helen. "The formation of halocarbons by marine organisms". Thesis, Bangor University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280676.
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Adams, John Anthony. "Benthic calcareous algae as Jurassic marine temperature indicators in Western Europe". Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55372/.
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The determination of calcareous chlorophyte distributional limits is via temperatures---namely isocrymal limits, because the green algae are very susceptible to cold temperatures. The calcereous green algae are today and were in the past, one of the most sensitive and useful environmental indicators. As well as being useful in distribution analysis, they are a useful part of biotic analysis in general. Calcareous green algae are mostly, but not wholly tropical in nature---they are found in shallow marine environments up to their range extent of just into temperate water masses (12°C isocrymal). The Dasycladales were dominated form of calcareous alga in the Jurassic (today their role has been largely taken over by the Halimidaceae). It can be seen that in the Upper Jurassic (where there are enough datapoints to form a reasonable limit, as opposed to the Lower or Mid Jurassic) that the Halimedaceae appeared to terminate at a line slightly southwards of the Dasycladales (this compares with the modern situation of a shared termination limit). Modern calcareous Chlorophyta distributions can delimit in the 12°C isocrymal water temperature boundary, and this limit can be imposed on the Jurassic Chlorophyta distribution dataset for palaeothermometry purposes. Together with selected isotope values, it is possible to estimate Jurassic isocrymes across Western Europe. This suggests the possibility of creatures such as belemnites (which are used for isotopically derived palaeotemperatures) having recorded summer temperatures in their isotopes rather than annual average. Modern algal temperature value differences (isocrymal versus summer maximum) is by ∼10°C and this change in values for the Jurassic Chlorophyta produces temperature figures equivalent to a majority of the isotopically derived temperature values.
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McIntosh, Kyle Douglas. "Pharmaceutical applications and toxicity of extracted alkenones from marine Isochrysis algae". University of Toledo Health Science Campus / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=mco1564780576118206.
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January, Grant Garren. "Bioprospecting for bioactive polysaccharides from marine algae endemic to South Africa". University of the Western Cape, 2016. http://hdl.handle.net/11394/5322.
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>Magister Scientiae - MScFucoidan is a marine-derived sulphated polysaccharide with bioactive properties ideal for the food, chemical and pharmaceutical industries. The polysaccharide consists largely of L-fucose, has a highly heterogeneous structure and is of diverse origin. Fucoidan was extracted from Ecklonia maxima, Laminaria pallida and Splachnidium rugosum and the effect of different extraction methods on fucoidan heterogeneity was assessed. Extraction methods employed hot water, hydrochloric acid or calcium chloride salt. Fucoidan yield and purity were determined by various colorimetric assays. Highest fucoidan yield was obtained with the hot water extraction method as seen by highest L-fucose content. Splachnidium rugosum extracts contained ~5 times more L-fucose than Ecklonia maxima and Laminaria pallida extracts. The salt extraction method yielded extracts free of contaminants, however L-fucose content in all extracts was >20 times lower. Acid extraction yielded highest levels of uronic acid contamination and liberated sulphate from the fucoidan polysaccharide. The fucose-to-sulphate ratio for Ecklonia maxima was approximately 1:5, whilst the ratios for Splachnidium rugosum and Laminaria pallida were approximately 1:1 and 1:2, respectively. The acid and salt extraction methods removed all traces of protein contaminants, while the hot water method retained very low levels of protein. The extraction method used to isolate fucoidan was a determining factor in yield and purity. Chemical compositional analyses of hot water extracts were assessed by gas chromatography mass spectroscopy. Splachnidium rugosum and Laminaria pallida extracts consisted largely of L-fucose, while Ecklonia maxima fucoidan was characterized with high glucose abundance. Crude hot water and acid extracts from Splachnidium rugosum tissue were fractionated and purified by (anionic) ion exchange chromatography as bioactivity has been correlated to lower molecular weight forms. In water extracts, ion exchange chromatography resulted in close to 90% decrease in L-fucose, sulphate and uronic acid, while protein content increased by 57%. Similar results were reported for acid extracts; however protein content did not change significantly. These results show that method of extraction may affect the composition of fucoidan post-purification. Hot water extraction is recommended due to higher fucoidan yield, as reflected by L-fucose content, and higher sulphate-to-fucose ratio. High protein content after ion exchange chromatography was however of concern. Since mucilage in Splachnidium rugosum thallus was free of protein, fucoidan was precipitated from mucilage with ethanol. Fucoidan yield of mucilage was >15-fold higher than content in purified hot water extracts with a sulphate-to-fucose ratio of ~1:1. The average molecular weight of native fucoidan in mucilage was estimated at 2367 kDa. The polysaccharide was hydrolysed by gamma-irradiation levels of 10-50 kGy to fractions ranging between 60 and 15.5 kDa. Hot water crude fucoidan extracts from Ecklonia maxima, Laminaria pallida, and Splachnidium rugosum were assessed for anti-oxidant activity by measuring the ability to scavenge free radicals and the capacity to reduce copper ions with 2,2-Diphenyl-1-picrylhydrazyl and Cupric Reducing Anti-oxidant Capacity assays, respectively. Ecklonia maxima crude fucoidan displayed highest anti-oxidant activity and capacity, having the potential to scavenge reactive oxygen species as well as the capacity to reduce copper to less toxic forms in mammalian systems. Splachnidium rugosum showed weakest anti-oxidant activity and lowest reducing capacity. The anti-cancer activity of crude and purified hot water Splachnidium rugosum extracts, as well as non-irradiated (native) and gamma-irradiated fucoidan, and commercially procured fucoidan were assessed for anti-cancer activity against MCF-7 breast cancer cells. Splachnidium rugosum crude and purified fucoidan displayed a half maximal inhibitory concentration of 0.7 mg/mL and 0.029 mg/mL, respectively. Low cytotoxicity of crude and purified Splachnidium rugosum fucoidan against non-cancerous breast epithelial cell line MCF-12A was observed, as seen by half maximal inhibitory concentration values of 2 mg/mL and 0.663 mg/mL, respectively. The cancer specific selectivity of purified Splachnidium rugosum fucoidan was therefore much higher as reflected by 10-fold higher selectivity index than that of crude fucoidan. Native and low molecular weight gamma-irradiated fucoidan also showed bioactive properties including anti-cancer activity as seen by the reduction of cell proliferation in vitro, whereas crude fucoidan showed the ability to scavenge free radicals, and the capacity to reduce copper ions.
National Research Foundation (NRF)
46
Jones, A. M. "Studies on fouling algae with specific reference to Ceramium rubrum c.a.Agardh". Thesis, University of Portsmouth, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370502.
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Lambade, S. B. "High density culture of marine microalgae using semi-continuous and continuous systems". Thesis, Central Marine Fisheries Research Institute, 1999. http://eprints.cmfri.org.in/11077/1/Lambade%20Sunil%20Bharguram.pdf.
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This study entitled "High density culture o f marine micro-algae using semicontinuous and continuous systems" was carried out with the objectives of devising small-scale low cost
systems for use in laboratory conditions. The study was carried out using two commonly used species of microalgae viz., the flagellate Isochrysis galbana and the diatom, Chaetoceros sp.
The system devised was a modified turbidostat (2 1 to 5 1) having three tier gravitational flow with manual controllers and without automation. For scale-up semicontinuous culture, a 60 1 capacity internally illuminated plexy glass culture system was devised.
Using 2.5 times the normal nutrient concentration, limited supply o f CO2 , activated charcoal filtered air and under sterile conditions it was possible to obtain upto 5 fold increase in culture cell density when compared to the normal batch cultures. Besides it was possible to maintain the cultures for durations varying from 2 to 5 weeks without collapse. In the continuous culture system o f 2 I capacity . The daily harvest o f high density culture amounted to 500 ml,
and in the semi-continuous system (4 1 capacity). The once-in-3 day harvest varied between 2-3 litres. From a single 60 1 capacity semicontinuous system running for 36 days the total
larvest amounted to 530 litres o f average 3.2 million cells/ml culture.
With respect to maricuhure, the application of conclusions derived from present.work would resut in increased efficiency and reduced cost of production of microalgae.
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Misciattelli, Natalia. "Control of pathogenic bacteria in marine larval culture systems". Thesis, Bangor University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311387.
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Fakee, Jameel. "The isolation and characterisation of secondary metabolites from selected South African marine red algae (Rhodophyta)". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001472.
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Secondary metabolites from natural sources are fast growing as popular drug leads. The structural novelty and favourable biological activity that these compounds display contribute to their popularity as drugs of the future. Examples of such compounds include the potent anticancer drug paclitaxel isolated from the bark of a yew tree as well as the more commonly known analgesic aspirin which stems from the bark of the willow tree. The biological activities exhibited by these secondary metabolites are vast and range from antimicrobial to anticancer activity to mention but a few. As a result, the isolation of novel compounds from natural sources is on the rise. The South African seaboard is home to a wealth of various marine algal species which produce fascinating secondary metabolites. For example, Portierria hornemanii was shown to produce halomon, a halogenated monoterpene which has displayed promising cytotoxic activity. This study thus focused primarily on pursuing novel compounds from three endemic South African marine algal species which have never been analysed previously from a chemical perspective. These are Plocamium rigidum (Bory de Saint-Vincent), Laurencia natalensis (Kylin) and Delisea flaccida (Suhr) Papenfuss. Four known compounds and one new halogenated monoterpene, (2E,5E,7Z)-8-chloro- 7-(dichloromethyl)-4-hydroxy-3-methylocta-2,5,7-trienal, were isolated from Plocamium rigidum. The breast cancer (MCF-7 cell line) inhibitory activity for these compounds was assessed and it was observed that an increase in the lipophilic nature of the compounds produced more favourable IC50 values. A pre-cursor to bromofucin type compounds, cis-laurencenyne, was isolated from Laurencia natalensis, as well as a new acetoxy chamigrane type compound, 4-bromo- 3,10-dichloro-7-hydroxy-3,7,11,11-tetramethylspiro [6.6] undec-1-yl acetate. Delisea flaccida was seen to contain two known bromofuranone type compounds isolated as an isomeric mixture, 1-[(5Z)-4-bromo-5-(bromomethylidene)-2-oxo-2,5- dihydrofuran-3-yl] butyl acetate and 1-[(5E)-4-bromo-5-(bromomethylidene)-2- oxo-2,5-dihydrofuran-3-yl]butyl acetate. These compounds are famous for their ability to inhibit bacterial biofilm production and they have been isolated before from an Australian Delisea sppAdobe Acrobat 9.53 Paper Capture Plug-in
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Hutchinson, Neil. "Spatial variation on tropical rocky shores : the role of herbivory and disturbance /". Thesis, Click to view the E-thesis via HKUTO, 1999. http://sunzi.lib.hku.hk/hkuto/record/B42575618.
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