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1
Tam, Carol Elizabeth. "A morphological and cytological study of Audouinella porphyrae and A. vaga (Rhodophyta)". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25055.
Testo completoAbstract (sommario):
A comparative study was made between two similar red algal endophytes, Audouinella porphyrae (Drew) Garbary and Audouinella vaga (Drew) Garbary, Hansen et Scagel, (Acrochaetiaceae, Acrochaetiales) and their red algal hosts Porphyra spp. and Pterosiphonia bipinnata, respectively. Both endophytes have axial, stellate chloroplasts with a central pyrenoid and reside in their host's cell walls, producing erect portions outside the host that may bear monosporangia. The endophytes were cultured "free" from their hosts and morphological and cytological features of the free-living forms were compared with field material. Although the two endophytes differ significantly in cell dimensions and branching patterns, the free-living forms do not retain these differences. Cell dimensions, branching patterns and developmental patterns are identical in the two free-living forms. Asexual reproduction with regeneration by monospores was observed. Sexual reproduction was not observed in either endophytic or free-living forms of the endophytes. Free-living forms were used for re-infection and cross-infection experiments. Under all experimental conditions, the endophytes showed only epiphytic growth. The hosts seem to have some effect on both of the endophytes. Epiphytes, Audouinella porphyrae and A. vaga were not selective and grew on both hosts, Porphyra torta and Pterosiphonia bipinnata. Both epiphtyes growing on blades of Porphyra tended to branch and have more extensive prostrate portions (3-5 cells) whereas both epiphytes on Pterosiphoni a bipinnata tend not to branch and have only 1-2 cells in the prostrate portions. Ultrastructural studies of both endophytes showed typical florideophycean features. Ultrastructural features of field material of the two endophytes were similar and free-living, cultured endophytes were similar to field material. A large vacuole was observed in sections of the field material of both prostrate and erect portions whereas this was not observed in cultured material. Based on the results of this study it is proposed that the two endophytes are conspecific. Audouinella vaga is referred to synonymy in Audouinella porphyrae (Drew) Garbary, Hansen et Scagel.Science, Faculty of
Botany, Department of
Graduate
2
Hunt, Jannine M. "A psbA phylogeny for selected rhodophyceae /". Electronic version (PDF), 2006. http://dl.uncw.edu/etd/2007-2/huntj/janninehunt.pdf.
Testo completo
3
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.
Testo completoAbstract (sommario):
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.
4
Browne, K. L. "Mariculture of the edible red algae, Palmaria palmata". Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368754.
Testo completo
5
Hector, Stanton Bevan Ernest. "Molecular studies of galactan biosynthesis in red algae". Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85620.
Testo completoAbstract (sommario):
Thesis (PhD)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Sulfated galactans (agarans and carrageenans) are accumulated in the cell wall of various red algae (Rhodophyta) species. These polysaccharides are of commercial importance in the food, pharmaceutical and biotechnology industries due to their unique physicochemical properties. Although having received significant research attention over the last 20 years, events regarding their biosynthesis have not been elucidated. Aiming for the identification of galactosyltransferase (GalT) genes involved in sulfated galactan biosynthesis, cDNA expression libraries were constructed from the prolific agar-producing South African red seaweed Gelidium pristoides (Turner) Kützing and screened by functional complementation of UDP-galactose 4-epimerase deficient mutants (E. coli and S. cerevisiae). Regretfully, no GalTs were identified. The study however yielded the first UGE enzyme described for a red seaweed. Southern hybridization indicated the presence of two UGE copies and confirmed the gene originated from G. pristoides. Bioinformatic analysis of G. pristoides UGE shows amino acid sequence homology to known UGEs from various organisms. The enzyme was shown to be functional in E. coli crude extracts and showed affinity for UDP-D-galactose, similar to other UDP-galactose 4-epimerases. Further, the isolated G. pristoides UGE (GpUGE) was biochemically characterized and its kinetic parameters determined. We found that there was no kinetic difference between this enzyme and previously described UGE enzymes except enhanced activity in the presence of exogenously added NAD+. The UDP-galactose 4-epimerase (UDP-glucose 4-epimerase, UGE, EC 5.1.3.2) is an essential Leloir pathway enzyme facilitating the catalytic inter-conversion between UDP-D-glucose and UDP-D-galactose. UDP-D-galactose is the nucleotide sugar required by galactosyltransferases for the production of red algae sulfated galactans. UGE is suspected as being responsible for supplying UDP-D-galactose for the synthesis of sulfated galactans. In planta monitoring of GpUGE transcript levels with respect to dark and light cycling indicated high expression of the enzyme at night, while expression diminished during the day. The occurrence of increased nocturnal UGE expression correlates with floridean starch breakdown at night. Evidence for hydrolysis of floridean starch is also reflected in obtained G. pristoides transcriptome sequence data. In red algae, floridean starch degradation coincides with sulfated galactan production. The detection of starch hydrolysis enzyme transcripts alongside increased expression of GpUGE suggests the enzyme plays a role in supplying UDP-Dgalactose for sulfated galactan production. As far as we know, this the first report of sequencing and biochemical characterization of a UGE from red seaweed.
6
Nylund, Göran M. "Epibiosis of red algae and algal metabolites as settlement inhibitors of the barnacle Balanus improvisus Darwin". Göteborg [Sweden] : Dept. of Marine Botany, Göteborg University, 1999. http://bibpurl.oclc.org/web/20311.
Testo completoAbstract (sommario):
Thesis (master's)--Göteborg University, 1999.Title from PDF t.p. (viewed on Sept. 25, 2007). At head of title: Tjärno Marine Biological Laboratory. Includes bibliographical references (p. 13-14).
7
Snare, David Joseph. "Mechanistic evaluation of red algal extracts that slow aging". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49050.
Testo completoAbstract (sommario):
Aging results from an accumulation of damage to macromolecules inhibiting cellular replication, repair, and other necessary functions. Damage may be due to environmental stressors such as metal toxicity, oxidative stress caused by imperfections in electron transfer reactions, or other metabolic processes. In an effort to discover medical treatments that counteract this damage, we have initiated a program to search for small molecule drugs from natural sources. We have identified marine red algae as a source of natural products that slow aging of the invertebrate rotifer Brachionus manjavacas. Rotifers are a promising model organism for life extension studies as they maintain a short, measurable lifespan while also having an accepted literature precedent related to aging. Rotifer lifespan was increased 9-14% by exposure to three of 200 screened red algal extracts. Bioassay guided fractionation led to semi-purified extracts composed primarily of lipids responsible for rotifer life extension. The life extending effects of these small molecule mixtures are not a result of their antioxidant capacity; instead they may activate pathways that slow the accumulation of cellular damage. An understanding of how these natural products interact with their molecular targets could lead to selective and efficient treatments for slowing aging and reducing age related diseases.
8
Goodman, Keri M. "Freshwater red algae use activated chemical defenses against herbivores". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41208.
Testo completoAbstract (sommario):
Chemically mediated interactions have important ecological and evolutionary effects on populations and communities. Despite recognition that herbivory can significantly affect the biomass and composition of freshwater macrophyte communities, there are few investigations of chemical defenses among freshwater vascular plants and mosses and none of freshwater red algae. This study compares the palatability of five species of freshwater red algae (Batrachospermum helminthosum, Boldia erythrosiphon, Kumanoa sp., Paralemanea annulata, and Tuomeya americana) that occur in the southeastern United States relative to two co-occurring macrophytes (the chemically defended aquatic moss Fontinalis novae-angliae and the broadly palatable green alga Cladophora glomerata). We assessed the potential role of structural, nutritional, and chemical traits in reducing macrophyte susceptibility to generalist crayfish grazers. Both native and non-native crayfish significantly preferred the green alga C. glomerata over four of the five species of red algae. B. erythrosiphon was palatable, while the cartilaginous structure of P. annulata reduced its susceptibility to grazing, and chemical defenses of B. helminthosum, Kumanoa sp., and T. americana rendered these species as unpalatable as the moss F. novae-angliae. Extracts from these latter species reduced feeding by ~30-60% relative to solvent controls if tissues were crushed (simulating herbivore damage) prior to extraction in organic solvents. However, if algae were first soaked in organic solvents that inhibit enzymatic activity and then crushed, crude extracts stimulated or had no effect on herbivory. B. helminthosum, Kumanoa sp., and T. americana all exhibited "activated" chemical defenses in which anti-herbivore compounds are produced rapidly upon herbivore attack via enzymatic processes. In an additional accept/reject behavioral assay, B. helminthosum extracts reduced the number of crayfish willing to feed by >90%.
Given that three of the five red algal taxa examined in this study yielded deterrent crude extracts, selection for defensive chemistry in freshwater rhodophytes appears to be substantial. Activated chemical defenses are thought to be an adaptation to reduce the resource allocation and ecological costs of defense. As such, activated chemical defenses may be favored in freshwater red algae, whose short-lived gametophytes must grow and reproduce rapidly. Roughly 20% of the known chemical defenses produced by marine algae are activated; further examination is needed to determine whether the frequency of activated chemistry is higher in freshwater red algae compared to their marine counterparts. Continued investigation of chemical defenses in freshwater red algae will contribute to among-system comparisons, providing new insights in the generality of plant-herbivore interactions and their evolution.
9
Renfrew, Dawn Elizabeth. "Gelidiales (rhodophyta, red algae) in British Columbia and Northern Washington : taxonomy, morphology, development". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29170.
Testo completoAbstract (sommario):
A study of the red algal order Gelidiales in British Columbia and northern Washington was conducted. Gelidiales are represented in the study area by four species, Gelidium coulteri, G. purpurascens, G. vagum and Pterocladia caloglossoides, and a key to identify the taxa is provided. Earlier reports of G. crinale, G. pusillum, G. robustum and G. sinicola from British Columbia and northern Washington have been shown to be misidentifications of the other taxa and are excluded from the flora. The occurrence of G. vagum in the British Columbian flora is significant because it appears to have been introduced from the northwest Pacific and now has a disjunct distribution, occurring in Japan and China and on two islands in the Strait of Georgia, British Columbia. Gelidium vagum and the Gulf of California species, G. johnstonii, are considered to be sister species. They share the unique character of monoecy (i.e. unique in the genus) and a morphological resemblance, but differ in several other characters, including arrangement of cortical cells, shape and flattening of tetrasporangial stichidia, shape of stichidial apices and position of the apical initial with respect to the adjacent cortex, presence/absence of an apical furrow and sterile margin in tetrasporangial stichidia and presence/absence of intact third order filaments in mature cystocarps.
The life history of Gelidium vagum was completed in culture, only the second Gelidium species for which this has been accomplished. Gelidium vagum has a triphasic Polysiphonia-type life history with isomorphic (monoecious) gametophytes and tetrasporophytes, and carposporophytes growing on gametophytes. The rare occurrence (G. purpurascens, G. coulteri) or absence (Pterocladia caloglossoid.gametophytes in the field and the lack of successful completion of a life history in culture suggests that, whereas these species may occasionally complete a Polysiphonia-type life history in situ, vegetative or apomictic mechanisms are more important in maintaining field populations. Chromosome counts of n = 14 - 15 were made on undivided tetrasporangia of G. vagum.
The pattern of spore germination in Gelidium coulteri, G. purpurascens and G. vagum is similar for carpospores and tetraspores. A single germ tube grows from the spore, the entire cytoplasmic contents of the spore evacuate into the germ tube and a wall cuts the germ tube off from the empty spore. The germ tube divides unequally to form a concave and a fusiform cell. The primary attachment rhizoid forms from a derivative of the concave cell and the sporeling apical cell forms from a fusion cell derivative. As apical organization is established, the subapical cell produces two lateral periaxial cells.
Carpogonium and carposporophj'te development was followed in Gelidium purpurascens and G. vagum. The functional carpogonium is intercalary. Non-functional carpogonia divide transversely with a concave wall and become sessile and degenerate. The fertilized carpogonium consistenty forms a fusion cell by fusing with adjacent cortical cells. Fusion cell lobes cut off gonimoblast filaments that send out processes that fuse with haploid gametophyte cells of nutritive chains. Carposporangia are produced terminally and laterally by gonimoblast cells and protrude into two locules that have formed as the cortex is pushed away from the plate of second order filaments. Carpospores are released through a single ostiole in each locule.
Spermatogenesis, tetrasporogenesis and rhizine morphology were studied ultrastructurally for the first time in Gelidiales. In spermatangial development, apical chloroplasts in the spermatangial mother cell are cut off by a furrow, a mechanism previously not reported in red algae for exclusion of chloroplasts from spermatangia. As the spermatangium matures, spermatangial vacuoles form from the coalescence of vesiculated endoplasmic reticulum and dictyosome-derived vesicles. Spermatangial vacuoles are discharged from the spermatangium just prior to the release of the spermatium.
Stages of tetrasporangium development are marked by wall development. Prior to karyokinesis, the young tetrasporangium is dominated by a large nucleus. Following karyokinesis, chloroplasts, starch grains and dictyosomes increase in abundance, a wall layer is deposited, and dictyosomes undergo a series of morphological changes from small and flat, to large and flat producing fibrillar vesicles, to hemispherical and producing cored vesicles. At cytokinesis an electron dense wall layer is deposited around the tetrasporangium and in the cleavage furrow, and cored vesicles secrete a mucilage-like material inside this wall layer.Science, Faculty of
Botany, Department of
Graduate
10
Biswas, Rajib. "Biomethanation of Red Algae from the Eutrophied Baltic Sea". Thesis, Linköping University, Department of Water and Environmental Studies, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51338.
Testo completoAbstract (sommario):
In the semi-enclosed Baltic Sea, excessive filamentous macro-algal biomass growth as a result of eutrophication is an increasing environmental problem. Drifting huge masses of red algae of the genera Polysiphonia, Rhodomela, and Ceramium accumulate on the open shore, up to five tones of algae per meter beach. During the aerobic decomposition of these algal bodies, large quantities of red colored effluents leak into the water what are toxic for the marine environment. In this study, feasibility of anaerobic conversion of red algae Polysiphonia, rich in nitrogen and phosphorous, was investigated. Biogas and methane potential of Polysiphonia, harvested in two different seasons [October and March], was investigated through three different batch digestion experiments and laboratory scale CSTR [continuous stirred tank reactor] at mesophilic (37oC) condition. Autoclavation [steam and heat] and ultrasound pretreatments were applied in order to enhance the biodegradation. In STR, anaerobic codigestion of algal biomass with SS [sewage sludge] was applied with a gradual increase in organic loading rate [1.5-4.0 g VS/L/day] and operated for 117 days at 20days HRT [hydraulic retention time]. Reactor digestate was analyzed four times over the period to determine the nutrients and heavy metals content. It is concluded that the methane potential of algae harvested in October is almost two-fold than that of algae harvested in March, probably due to it’s higher [more than double] nitrogen richness. An increase in biogas yield was observed upto 28% and VS reduction was increased from 37% to 45% due to autoclave pretreatment. Ultrasound pretreatment had no effect on digestion. In batch digestion, maximum methane yield 0.25 m3/kg VS added at 273oK, was obtained from algae [harvested in October] pretreated in autoclave. Codigestion of algae with SS worked well in STR with a comparatively lower OLR. At a higher OLR, methanogens were inhibited due to increased VFAs accumulation and decreased pH. A maximum biogas yield 0.49 m3/kg VS added at 310oK , was obtained from algae [harvested in October] pretreated with autoclave. The methane content of the produced biogas was 54%. Average [over a short period, day 99-107, reactor showed steady performance] maximum biogas yields from untreated algae obtained 0.44 m3/kg VSadded at 310oK and the VS reduction was calculated 32%. Digestate, to be used as a fertilizer, was found NH4-N, N, P, K, S and Na rich and only Cadmium level was above the maximal limit among the heavy metals. The sand content in algae during harvesting was considered as a factor to disrupt the operation. Codigestion of Polysiphonia algal biomass with substrate with higher C:N ratio like paper mill waste should be more appropriate to increase the methane and biogas yield. It is inconclusive whether AD process is a good method to dewater redalgae or not but large scale harvesting of algae will definitely contribute to curb eutrophication of the Baltic Sea through decreasing N and P level.
11
Broberg, Anders. "Structural and quantitative studies of metabolites in red algae /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5476-X.gif.
Testo completo
12
Beaugeard, Marie. "Biosorption of heavy metals by red algae (Palmaria palmata)". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31190.
Testo completoAbstract (sommario):
The research presented in this thesis entailed an investigation of heavy metal uptake by Palmaria palmata, a red marine alga. The alga was dry and organically certified. The heavy metals of interest were those commonly found in the wastewaters of the printed wiring board industry, namely Cu2+Pb2+, Cd2+, Zn 2+ and Ni2+. The ultimate objective of the work was to determine whether or not the factors expected to influence the metal uptake to the greatest extent could be optimized within functional ranges, leading eventually to process design (beyond the scope of this thesis). These factors were pH, temperature, initial concentration of metal in aqueous solution, and contact time. A number of preliminary experiments were performed to establish a basis for the design of the optimization studies.Although it was not possible to adequately define optimal regions of operation for the biosorption of heavy metals by Palmaria palmata , general trends were elucidated, and the limitations of the methodology used were clarified. (Abstract shortened by UMI.)
13
Borgmann, Ira Elizabeth. "A preliminary electrophoretic stury on Bangia vermicularis Harvey (Rhodophyta) populations of British Columbia". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26171.
Testo completoAbstract (sommario):
A preliminary electrophoretic study on Bangia vermicularis Harvey (Rhodophyta) along the coast of British Columbia was undertaken to determine whether enzyme banding patterns could be used to identify the relatedness of the populations which varied in chromosome number (3, 6 or 4) and life history (asexual or sexual). Material from nineteen sites was tested for seven enzymes: glutamate dehydrogenase (GDH); malate dehydrogenase (MDH); lactate dehydrogenase (LDH); superoxide dismutase (SOD), glucose 6-phosphate dehydrogenase (G6PDH); phosphoglucoisomerase (PGI); and phosphoglucomutase (PGM). Unlike higher plants, some of the banding patterns obtained in Bangia could only be explained if the enzymes SOD, GDH, LDH and PGI are monomers and the enzymes PGM, SOD, GDH, PGI, and G6PDH have only one cellular location. Generally, with the exception of two enzymes, PGI and G6PDH, which were highly polymorphic, only one to three bands were evident. Considerable amounts of variation in the mobility of the isoenzymes were detected between populations independent of chromosome number or sexuality. Contrary to expectations, often populations with three chromosomes or six ' chromosomes had the same number of loci and many of the three chromosome populations had some banding patterns indicative of diploids. Consequently, if there had been a polyploid origin of the six chromosome populations then there must also have been many gene duplications in the three chromosome populations. Alternatively, if the three chromosome populations arose by aneuploid reduction within a six chromosome population then there must also have been gene silencing and/or the formation of null alleles. Populations that were very close geographically differed to a large extent suggesting that there may be little gene flow between populations. The variability between populations could be explained by isolation over long periods of time during which changes could have occurred in the structure and regulation of the enzymes tested.Science, Faculty of
Botany, Department of
Graduate
14
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/.
Testo completoAbstract (sommario):
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.
15
Woelkerling, William J. "Aquatic botanical studies : with special reference to the red algal families, Corallinaceae and Acrochaetiaceae /". Title page, contents and abstract only, 1986. http://web4.library.adelaide.edu.au/theses/09SD/09sdw842.pdf.
Testo completo
16
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.
Testo completoAbstract (sommario):
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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Maneveldt, Gavin W. "A global revision of the nongeniculate coralling algal genere Porolithon Foslie (defunct) and Hydrolithon Foslie (Corallinales, Rhodophyta)". Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
Testo completoAbstract (sommario):
The purpose of this thesis was to provide a revision and characterization of the species of nongeniculate coralline algae previously ascribed to the now defunct genus Porolithonto provide a modern account of selected taxa from the genus Hydrolithon and descriptions of taxa found to conform the generic delimitation of Hydrolithon and to use a phenetic cluster analysis to determine the taxonomic relationships between the various taxa ascribed to the genera Polorithon and Hydrolithon.
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Mmonwa, Lucas Kolobe. "Phylogeography and epifauna of two intertidal seaweeds on the coast of South Africa". Thesis, Rhodes University, 2009. http://eprints.ru.ac.za/1583/.
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Pettitt, T. R. "Lipid metabolism and membrane function in two species of marine red algae". Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382614.
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Prathep, Anchana. "Population ecology of a turf-forming red alga, Osmundea pinnatifida from the Isle of Man, British Isles". Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250454.
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Alexander, Paul. "The responses of crops and soils to calcified seaweed". Thesis, University of Wolverhampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323090.
Testo completo
22
Saravanakumar, Denise. "Antimycobacterial activity of the red algae gelidium pristoides, plocamium corallorhiza and polysiphonia virgata". Doctoral thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/8912.
Testo completoAbstract (sommario):
Summary in English.In 1993, the World Health Organisation declared tuberculosis a global health emergency. Currently, efforts are underway to improve the way the disease is managed and to find more effective treatments that would combat the problem of long treatment periods, toxicity, drug-resistance and HIV-coinfection. In the process, natural product chemistry continues to play an important role in the search for new compounds to treat tuberculosis. Terrestrial plants have been investigated for antimycobacterial activity, while marine plants are yet to receive as much attention. In this project, three South African marine plants were drawn into the search for novel anti-tuberculosis compounds. One of the seaweeds is already part of the local seaweed industry, namely Gelidium pristoides, while Plocamium corallorhiza and Polysiphonia virgata have economic potential. These three red algae were extracted extensively and fractionated using preparative layer chromatography and preparative centrifugally accelerated radial thin-layer chromatography (Chromatotron). The crude extracts of the algae showed no inhibitory activity to growth of the causative agent of human tuberculosis, Mycobacterium tuberculosis. However, when the purified fractions were tested against M. tuberculosis in the BACTEC-460 radiometric method at a concentration of 125 μg/mL, fractions 322, 323 and 333 of P. virgata showed 100% inhibition, while two fractions of G. pristoides showed 91.7% and 79.2% inhibition, respectively. Two fractions of P. corallorhiza demonstrated 41.2% and 73.5% inhibition. The bioactive fractions of P. virgata were further purified and resulted in the isolation of a known compound namely, 2-methoxyethyl-2-methacrylate (MEMA). When MEMA was tested by radiometric assay against M. tuberculosis, it showed anti-tuberculosis activity at a MIC-value of 100 μg/mL and no cytotoxicity against Chinese hamster ovarian cells. However, in a re-investigation into the bioactive compounds of P. virgata it was established that MEMA was not the major bioactive compound. Long chain fatty acids were responsible for the antimycobacterial activity of the algal extract particularly oleic acid, linoleic acid, dodecanoic acid, and myristic acid. Oleic acid inhibited the growth of M. tuberculosis at and MIC-value of 25 11 g/rnL, while dodecanoic acid, myristic acid and linoleic acid all had MIC-values of 50 μg/mL. Stearic acid and palmitic acid was also isolated from the seaweed, but only moderate inhibition of M. tuberculosis was observed for at MIC-values of 50 μg/mL. Oleic acid showed moderate inhibition at 50 μg/mL against the multi-drug resistant isolate of M. tuberculosis, while myristic acid and dodecanoic acid showed significant inhibition against the same at 50 μg/mL and moderate inhibition at 25 μg/mL. Linoleic acid also inhibited the growth of the multi-drug resistant strain at 50 μg/mL. Oleic acid showed the most inhibition of the growth of M. smegmatis in direct bioautography with an MIC-value of 0.8 μg/mL, while linoleic acid and dodecanoic acid had MIC-values of 1.56 μg/mL and 3.125 μg/mL., respectively. Stearic acid, palmitic acid, and myristic acid did not inhibit the growth of M. smegmatis.
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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.
Testo completoAbstract (sommario):
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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Knott, Michael George. "Isolation, structural characterisation and evaluation of cytotoxic activity of natural products from selected South African marine red algae". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1015460.
Testo completoAbstract (sommario):
The medicinal chemistry of selected marine algae indigenous to South Africa was investigated. Following the isolation and characterisation of a number of new and known compounds, the associated in vitro cytotoxic profiles of these new compounds was investigated. Plocamium maxillosum yielded two new cyclic polyhalogenated monoterpenes which were characterised as 2E-chloromethine-4E-chlorovinyl-4-methyl-5-cyclohexen-1-one (2.1) and 2Z-chloromethine-4E-chlorovinyl-4-methyl-5-cyclohexen-1-one (2.2) on the basis of one and two dimensional NMR spectroscopic data and MS analysis. These compounds were also found to have good cytotoxic activity against breast cancer cell lines. Although these compounds are based on a regular monoterpene skeleton, they represent an uncommon feature not often seen in cyclic halogenated monoterpenes from marine algae. Plocamium robertiae yielded one new cyclic polyhalogenated monoterpene identified as 4,5- dibromo-5-chloromethyl-1-chlorovinyl-2-chloro-methylcyclohexane (2.6) and one known compound called 2,4-dichloro-1-chlorovinyl-1-methylcyclohexane-5-ene or Plocamene D (2.9). Portieria hornemannii was collected from Port Edward in Natal and yielded three new compounds, namely; 3Z-1,6-dibromo-3-(bromomethylidene)-2,7-dichloro-7-methyloctane (3.1), 1E,3Z-1,6-dibromo-3-(bromomethylidene)-7-chloro-7-methyloct-1-ene (3.2), 1Z,3Z- 1,6-dibromo-3-(bromomethylidene)-7-chloro-7-methyloct-1-ene (3.3), and one known compound, namely; 3S,6R-6-bromo-3-(bromomethyl)-3,7-dichloro-7-methyloct-1-ene (3.4). Compounds 3.1 and 3.2 showed no cytotoxic activity against breast cancer cells. Another Portieria hornemannii sample was collected from Noordhoek in the Eastern Cape, it yielded one known compound referred to as 3Z-6-bromo-3-(bromomethylidene)-2,7- dichloro-7-methyloct-1-ene (3.5), as well as one new compound called portieric acid A (3.6) or 5-bromo-2-(bromomethylidene)-6-chloro-6-methylheptanoic acid. Portieric acid A showed slight cytotoxic activity and also represents a new class of compound within the genus Portieria. The isolation of secondary metabolites from the South African red alga, Laurencia glomerata, yielded two known compounds; 7-hydroxylaurene (4.9) and cis-neolaurencenyne (4.12), as well as one chamigrane related compound (4.11). Laurencia flexuosa yielded one known compound called 3Z-bromofucin (4.13). Using 1H NMR, GC and molecular systematics, a novel method for identifying different species of Laurencia was also investigated.
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Stuercke, Brooke. "An integrated taxonomic assessment of North Carolina Polysiphonia (Ceramiales, Rhodophyta) species /". Electronic version (PDF), 2006. http://dl.uncw.edu/etd/2006/stuerckeb/brookestuercke.pdf.
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Tiwari, Sunil. "Effect of Different Light Intensities on Freshwater Red Algae Batrachospermum gelatinosum: A Transcriptomic Approach". Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou159671675380422.
Testo completo
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Van, der Merwe Elizabeth. "Systematics of the non-geniculate coralline red algae from the South African south coast". University of the Western Cape, 2015. http://hdl.handle.net/11394/4818.
Testo completoAbstract (sommario):
Philosophiae Doctor - PhDThe aim of this study was to document the intertidal and shallow subtidal species of non-geniculate coralline red algae from the South Africa south coast. The main emphasis of the study are encompassed in four research chapters and one concluding chapter focusing on: 1) the documentation of the non-geniculate coralline red algae occurring along the South Africa south coast; 2) revisiting the Leptophytum-Phymatolithon complex in order to resolve the taxonomic status of species previously ascribed to the genus Leptophytum from South African; 3) starting to prepare modern monographic accounts of the higher taxa; and 4) the production of updated keys to all the currently recognised taxa of non-geniculate coralline algae for South Africa. Although nowhere near complete, here we present our findings and report on the current biodiversity status of the non-geniculate coralline red algae after a further four years of extensive sampling.
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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.
Testo completoAbstract (sommario):
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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Lawson, Jessica Clair. "Analysis of the anti-cancer activity of novel indigenous algal compounds in breast cancer: towards the development of a model for screening anti-cancer stem cell activity". Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1003984.
Testo completoAbstract (sommario):
Breast cancer, the most common malignancy diagnosed in women, is one of the leading causes of death in women worldwide. In South Africa only 32% of women diagnosed with advanced breast cancer survive more than five years. The search for new chemotherapeutic agents capable of effectively treating breast cancer is therefore essential. Recent evidence supporting the cancer stem cell theory of cancer development for breast cancer challenges the current theories of cancer development and hence treatment. Cancer stem cells are a small subpopulation of tumour cells that possess properties of both cancer cells and stem cells and are believed to be the tumour-initiating population of many cancers. Cancer stem cells are inherently resistant to many chemotherapeutic agents and in this way have been associated with repopulation of tumours after chemotherapy. This phenomenon is proposed as a possible mechanism for cancer relapse after treatment. Cancer stem cells have also been implicated in metastasis, the major cause of mortality in cancer patients. Therefore, any treatment that is capable of targeting and removing breast cancer stem cells may have the theoretical potential to effectively treat breast cancer. However, there are currently no such treatments available for clinical use. We were provided access to a library of novel indigenous small molecules isolated from red and brown algae found off the Eastern Cape of South Africa. The aim of this project was to analyse the anti-cancer and anti-cancer stem cell properties of the compounds in this library and to identify „hit‟ compounds which could form the basis for future development into new anti-cancer drugs. Ten novel compounds of algal origin were tested for cytotoxicity, by determining their ability to inhibit the growth of MCF12A breast epithelial cells and MCF7 breast cancer cells using the colorimetric MTT [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cell proliferation assay. All but one of the compounds tested exhibited cytotoxicity towards the MCF7 cancer cell line, with IC50 values (the concentration of the compound that leads to a 50% inhibition in cell growth) of between 3 μM and 90 μM. The chemotherapeutic drug paclitaxel was used as a positive control. Four of the compounds (RUMB-001, RUMB-002, RUMB-007 and RUMB-010/saragaquinoic acid) were significantly more toxic to the MCF7 cancer cell line, than the „normal‟ MCF12A breast cells and were selected as priority compounds for further analyses. In addition, two other compounds were selected as priority compounds, one highly cytotoxic towards both MCF12A and MCF7 cell lines (RUMB-015) and one which was non toxic to either cell line (RUMB-017/018). Preliminary studies into the mechanism of cytotoxicity using Western blot analysis for poly (ADP-ribose) polymerase (PARP) cleavage and Hoechst 33342 immunostaining in MCF-7 cells were largely unsuccessful. The Hoechst 33342 immunostaining assay did provide tentative evidence that selected priority compounds were capable of inducing apoptosis, although these assays will need to be repeated using a less subjective assay to confirm the results. The priority compounds were subsequently investigated for their cytotoxic effect on the cancer stem cell-enriched side population in MCF7 cells. The ability of the priority compounds to selectively target the cancer stem cell containing side population was assessed using two complementary flow cytometry-based techniques – namely the Hoechst 33342-exclusion assay, and fluorescent immunostaining for the expression of the putative cancer stem cell marker, ABCG2+. The ABCG2+ staining assay was a novel technique developed during the course of this study. It remains to be fully validated, but it may provide a new and reliable way to identify and analyse cancer stem cell containing side population cells. The MCF7 cells were treated with the compounds and the proportion of putative cancer stem cells compared with the size of the population in untreated cells was assessed. Three compounds (RUMB-010, RUMB-015 and RUMB-017/018) capable of reducing the proportion of side population cells within the MCF7 cell line were identified. Taking these data together, we identified two potential „hit‟ compounds which should be prioritised for future research. These are compounds RUMB-010/sargaquinoic acid and RUMB-017/018. RUMB-010 is of interest as it was shown to target the putative cancer stem cell population, in addition to the bulk MCF7 tumour line, but was relatively less toxic to the „normal‟ MCF12A cell line. RUMB-017/018 is of interest due to the ability to selectively target the cancer stem cell enriched side population, while having little effect on the normal (MCF12A) or bulk tumour (MCF7) cell lines tested. These compounds will be important as „hit‟ compounds for drug development and as tool compounds to study cancer and cancer stem cell biology.
30
Knott, Michael George. "The natural product chemistry of South African Plocamium species". Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1004920.
Testo completoAbstract (sommario):
The brine shrimp lethality assay was used as a preliminary tool to screen eighteen seaweeds collected from the South African coast. Of the seaweeds tested, the red algae Plocamium corallorhiza and Hypnea rosea, and the green alga Halimeda sp., showed the most potent activity. The chemical investigation of P. corallorhiza resulted in the isolation and structural elucidation of five previously undescribed secondary metabolites, along with three known compounds and four possible artifacts of the extraction process. Standard spectroscopic methods and comparison with known compounds were used to determine the structures of the new metabolites. The new compounds included the linear halogenated monoterpenes 4,8-dibromo-1, 1-dichloro-3,7-dimethyl-2,6-octadiene (99), 4,6-dibromo-l, 1-dichloro-3,7-dimethyl-2,7-octadiene (100), 4,8-dibromo-l, 1,7-trichloro-3,7-dimethyl-2,5-octadiene (101) and 3,4,6,7-tetrachloro-3,7-dimethyl-l-octene (102) and the cyclic monoterpene 5-bromo-5-bromomethyl-I-chlorovinyl-2,4-dichloro-methylcyclohexane (103) while the known compounds were identified as 4-bromo-5-bromomethyl-1chlorovinyl-2,5-dichloro-methylcyclohexane (35), 1,4,8-tribromo-3, 7 -dichloro-3,7-dimethyl-1,5-octadiene (94) and 8-bromo-1,3,4,7-tetrachloro-3,7-dimethyl-1,5-octadiene (96). The four methoxylated compounds (104-107) were presumably formed via a standard substitution reaction between the halogenated monoterpenes 96 and 101 and MeOH, which was used as a component in the extraction solvent. With over 100 000 natural products having been reported, it has become necessary to employ an efficient dereplication strategy to quickly identify known compounds. A simple Gas Chromatography-Mass Spectrometry (GC-MS) method for the efficient physicochemical screening, identification and dereplication of Plocamium metabolites was developed. In this study the crude extracts of P. corallorhiza, P. cornutum and P. maxillosum were screened by GC-MS and the retention times and mass spectral fragmentation patterns of compounds 94, 96, 99 - 107 were used to quickly identify known and new compounds in the crude extracts of P. cornutum and P. maxillosum. This data indicated that compounds 99, 100, 103 were present in both P. corallorhiza and P.cornutum, while compound 102 was found to be present in P. corallorhiza, P. cornutum and P. maxillosum. These studies also indicated that ecotypes and chemotypes are not a significant feature of P. corallorhiza and P. cornutum. Different species of Plocamium (namely: P. corallorhiza, P. cornutum, and P. maxillosum) have very different chemical profiles, and GC may therefore have appreciable taxonomic application in the identification of the different Plocamium spp. which are endemic to South Africa.
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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.
Testo completo
32
Narendar, Priyanka. "Screening and Identification of Everglades Algal Isolates for Biodiesel production". FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/287.
Testo completoAbstract (sommario):
This project investigates the potential of the 27 Everglades green algal strains for producing biodiesel. The five potential strains chosen by measuring the neutral lipid content using the Nile red method were Coelastrum 46-4, Coccoid green 64-12, Dactylococcus 64-10, Stigeoclonium 64-8 and Coelastrum 108-5. Coelastrum 108-5 and Stigeoclonium 64-8 yielded the same amount of lipids in both Gravimetric and Nile red method. A linear relationship between algal biomass and lipid accumulation was seen in Coelastrum 46-4, Coccoid green 64-12, Stigeoclonium 64-8 and Coelastrum 108-5 indicating that increase in algal biomass increased the lipid accumulation. Nitrogen and phosphorous stress conditions were also studied where higher lipid accumulation was observed significantly (p < 0.05) in 64-8 Stigeoclonium and 64-12 Coccoid green. Collectively, it could be summarized that Coelastrum 108-5, Coccoid green 64-12 and Stigeoclonium 64-8 were promising in some aspects and could be used for further studies.
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Barreto, Michael. "Antimicrobial activity of macroalgae from Kwazulu-Natal, South Africa, and the isolation of a bioactive compound from Osmundaria serrata (Rhodophyta)". Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-09052005-095635/.
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Puckree-Padua, Courtney Ann. "The genus Spongites (Corallinales, Rhodophyta) in South Africa". University of the Western Cape, 2019. http://hdl.handle.net/11394/6957.
Testo completoAbstract (sommario):
Philosophiae Doctor - PhDCoralline red algae (Corallinales, Hapalidiales, Sporolithales: Corallinophycidae, Rhodophyta) are widespread and common in all the world’s oceans (Adey & McIntyre 1973; Johansen 1981; Littler et al. 1985; Björk et al. 1995; Aguirre et al. 2007; Harvey & Woelkerling 2007; Littler & Littler 2013). They achieve their highest diversity in the tropics and subtropics (Björk et al. 1995; Littler & Littler 2013; Riosmena-Rodríguez et al. 2017), and within the photic zone of rocky shores (Lee 1967; Littler 1973; Adey 1978; Adey et al. 1982; Steneck 1986; Kendrick 1991; Kaehler & Williams 1996; Gattuso et al. 2006; van der Heijden & Kamenos 2015; Riosmena-Rodríguez et al. 2017) where they serve as important carbonate structures (Adey et al. 1982; Littler & Littler 1994, 1997; Vermeij et al. 2011) and habitats for a host of marine species (Foster 2001; Amado-Filho et al. 2010; Foster et al. 2013; Littler & Littler 2013; Riosmena-Rodríguez et al. 2017). Coralline algae are resilient, inhabiting extreme conditions that include: low temperatures (Adey 1970, 1973; Freiwald & Hendrich 1994; Barnes et al. 1996; Freiwald 1996; Aguirre et al. 2000; Roberts et al. 2002; Björk et al. 2005; Martone et al. 2010); limited light exposures (Adey 1970; Littler & Littler 1985; Littler et al. 1985; Liddell & Ohlhorst 1988; Dullo et al. 1990; Littler & Littler 1994; Iryu et al. 1995; Stellar and Foster 1995; Gattuso et al. 2006; Aguirre et al. 2007; Littler & Littler 2013); severe wave action (Steneck 1989; Littler & Littler 2013); intense grazing pressures (Steneck 1989; Steneck & Dethier 1994; Maneveldt & Keats 2008; Littler & Littler 2013), highly fluctuating salinities (Harlin et al. 1985; Barry & Woelkerling 1995; Barnes et al. 1996; Wilson et al. 2004); including occurring in freshwater (Žuljevic et al. 2016), and constant sand scouring (Littler & Littler 1984; D’Antonio 1986; Kendrick 1991; Chamberlain 1993; Dethier 1994).
35
Silva, Daniel Lira da. "Aplicação de cromatografia gasosa acoplada à espectrometria de massas na identificação de substâncias obtidas de algas marinhas de dois estados do Nordeste brasileiro". Universidade Federal de Alagoas, 2014. http://www.repositorio.ufal.br/handle/riufal/2149.
Testo completoAbstract (sommario):
Seaweeds are organisms which live in oceans and seas. They have ability to perform photosynthesis and feed many species of aquatic organisms. Macroalgae, which can be divided by characteristic colors in: Red algae (Phylum Rhodopyta), Green algae (Phylum Chlorophyta) and Brown algae (Class Phaeophyceae). Seaweeds are used for centuries by Asians as an important part of their diet, and also as source of compounds to Pharmaceutical and Cosmetic industries. The Brazilian Northeastern has a large coastal area; it possesses several forms of marine organisms especially for being in a Tropical hot water zone. Based on the importance of macroalgae, a chemical study was conducted using five species of algae (Bryothamnion seaforthii; Colpomenia sinuosa; Dictyosphaeria versluysii, Digenea simplex and Galaxaura rugosa) to prepare methanolic extracts and sequential fractions. 72 substances
were identified using the GC-MS technique under the following operation conditions: helium as the carrier gas; 1.52 mL/min flow rate; oven temperature 60 º (25 ºC/min 300 ºC, heating rate); Splitless; injected volume 1 μL; solvent cutting 3 minutes. The mass spectra were obtained in the same equipment by electron impact ionization (EI) at 70 eV; and the ion source was maintained at 300 ° C. Hexadecanoic acid, in all fractions; 1-isopropyl-1,3,4-trimethyl-cyclohexane, 1,4-diisopropyl-cyclohexane and isopentyl decanoate, first identified in seaweeds; several esters, hydrocarbons and fatty acids can be mentioned as identified substances.Conselho Nacional de Desenvolvimento Científico e Tecnológico
Alga é uma forma de vida que vive em oceanos e mares e possui a capacidade de realizar fotossíntese e servir de alimento e/ou abrigo para muitas espécies de organismos aquáticos. As macroalgas, que podem ser divididas pela cor característica que possuem, em algas vermelhas (Filo Rhodophyta), verdes (Filo Chlorophyta) e pardas (Classe Phaeophyceae), são utilizadas pelos orientais como parte importante de sua alimentação há vários séculos, além de utilizá-las como fonte de produtos farmacêuticos e da indústria de cosméticos. O nordeste brasileiro possui uma vasta área litorânea e costeira sendo rico em diversas formas de vida marinha, principalmente por estar em uma zona tropical de águas quentes. Com base na importância destas macroalgas, foi realizado um estudo químico de cinco espécies de algas, Bryothamnion seaforthii, Colpomenia sinuosa, Dictyospharia versluysii, Digenea simplex e Galaxaura rugosa, através de extratos metanólicos e frações. A técnica de cromatografia gasosa acoplada à espectroscopia de massas foi utilizada com as seguintes condições de operação: hélio como gás de arraste; velocidade do fluxo, 1,52 mL/min; a temperatura inicial do forno foi 60 ºC, com uma taxa de aquecimento de 25 ºC/min até 300 ºC; “Splitless”, como modo de injeção; 1 μL de volume injetado; e corte do solvente em 3 minutos. O tempo total de corrida foi 25 minutos. Os espectros de massas foram obtidos no mesmo equipamento, através de ionização por impacto de elétrons (EI) de 70 eV; e a fonte de íons foi mantida a 300 ºC. Desse modo foram identificadas 72 substâncias, dentre as quais podem ser citadas: ácido hexadecanoico, presente em todas as frações; os hidrocarbonetos 1-isopropil-1,3,4-trimetilcicloexano, 1,4-di-isopropilcicloexano e decanoato de isopentila, identificados pela primeira vez em algas; além de diversos ésteres, hidrocarbonetos e ácidos graxos.
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Bui, Tran Nu Thanh Viet. "Structure, Rheological Properties and Connectivity of Gels Formed by Carrageenan Extracted from Different Red Algae Species". Thesis, Le Mans, 2019. http://www.theses.fr/2019LEMA1007/document.
Testo completoAbstract (sommario):
Les carraghénanes (Car) sont des polysaccharides linéaires sulfatés extraits d’algues rouges et sont très utilisés en tant qu’épaississants et gélifiant en industrie. Les rendements d’extraction ainsi que les propriétés physicochimiques de Car extraits de différentes espèces cultivées dans la baie de Cam Ranh au Vietnam ont été déterminés. Pour les variantes kappa et iota, les propriétés rhéologiques et de la microstructure en solution seuls ou en mélange à différentes concentrations en présence de CaCl2 ou de KCl. Leurs mélanges présentent une gélification thermique en deux étapes qui correspondent chacune aux gélifications du kappa et iota seuls. Cependant, pour les mélanges, l’élasticité du gel est nettement supérieure à la somme de celle des Car seuls. Des mesures en microscopie confocale et de turbidimétrie ont démontré que les gels obtenus avec le kappa étaient toujours plus turbides que ceux avec l’iota mais étaient moins turbides dans les mélanges. Au vus des résultats, un mécanisme de séparation de phase microscopique entre les deux Car semble très peu probable. Des mesures de FRAP (Recouvrance de Fluorescence Après Photo-blanchiment) ont permis de sonder la mobilité des chaînes de Car dans les gels pour les systèmes individuels ou les mélange. Dans tous les cas, il a été observée qu’une fraction des chaînes de Car reste mobile dans les gels. Cette fraction mobile varie de 25% à 75% selon le type de Car et le type/concentration en sel. Cette fraction n’est pas corrélée à la dureté du gel quelles que soient les conditions opératoires. De plus, il a été démontré que les chaines relarguées sont plus petites que la moyenne de l’échantillon initialCarrageenan (Car) is a polysaccharide extracted from red algae and is widely used as thickener, stabilizer and gelling agent in various products. Properties of Car extracted from different algae species cultured at Cam Ranh Bay in Vietnam were characterized. Kappa car extracted from K. alvarezii and iota Car from E.denticulatum were selected to study the rheological properties and the microstructure of individual and mixed car solutions in presence of CaCl2 and KCl. Mixtures showed a two-step gelation process with gelation temperatures that coincided with those of corresponding individual kappa and iota Car solutions. However, the stiffness of the mixed gels was much higher than the sum of the corresponding individual gels. Confocal laser scanning microscopy and turbidity measurements showed that the kappa Car gel was always more heterogeneous than the iota Car gel, but less in the mixture than in the individual system. The results show that microphase separation of iota and kappa Car in mixed gels is highly unlikely.The mobility of Car chains in individual gels of kappa and iota Car and their mixtures was determined using fluorescence recovery after photobleaching. Slow recovery was observed for the gels showing that a fraction of the Car chains remained mobile. The fraction of mobile chains in the gels varied between 25% and 75% depending on the type of Car and the type and concentration of salt. The fraction of mobile chains in gels was not correlated to the gel stiffness. These results were confirmed by the release of Car from gel fragments into excess solvent. It was found that released Car chains were smaller than the average size of the initial Car sample
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Mays, Kristin Leigh. "Ultrastructural Features of Tetrasporgenesis Within the Corallinoideae and Taxonomic Implications for Coralline Red Algae (Corallinales, Rhodophyta)". W&M ScholarWorks, 1997. https://scholarworks.wm.edu/etd/1539626096.
Testo completo
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Johnston, Emily T. "The Systematic Revision of the Freshwater Red Algal Order Thoreales (Nemaliophycidae, Rhodophyta)". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1343406416.
Testo completo
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Stewart, Sarah Anna. "PHYLOGENETIC AFFINITIES OF AUSTRALASIAN SPECIMENS OF BATRACHOSPERMUM (BATRACHOSPERMALES, RHODOPHYTA) INFERRED FROM MOLECULAR AND MORPHOLOGICAL DATA". Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1155173575.
Testo completo
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Kregting, Louise Theodora, e n/a. "The relative importance of mainstream water velocity and physiology (nutrient demand) on the growth rate of Adamsiella chauvinii". University of Otago. Department of Botany, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070806.121216.
Testo completoAbstract (sommario):
A prevailing view exists in the literature which suggests that macroalgae growing in slow-flow environments (<4 cm s⁻�) are less productive because of "mass-transfer" limitation compared to fast-flow environments. Macroalgae in slow-flow environments are thought to have thicker diffusion boundary-layers which limit the flux of essential molecules to and from the algal thallus. However nutrient demand of a macroalga can also influence nutrient flux. The main objective of this research was to determine the relative importance of physical (mainstream velocity) and physiological (nutrient demand) factors influencing the growth rate of Adamsiella chauvinii, a small (<20 cm) red algal species, that grows within the benthic boundary-layer in a soft sediment habitat. To establish the influence of water velocity, the growth rate of A. chauvinii was measured in situ each month (March 2003 to March 2004) at three sites with varying degrees of water velocity (slow, intermediate and fast) at which all other environmental parameters (photon flux density, seawater temperature and nutrients) were similar. To determine the metabolic demand and nutrient uptake rate of A. chauvinii, the internal nutrient status (C:N, soluble tissue nitrate, ammonium and phosphate), uptake kinetics (V[max] and K[s]) and nutrient uptake rate at a range of mainstream velocities were also determined on a seasonal basis. The hydrodynamic environment around A. chauvinii canopies was characterised in situ and compared with controlled laboratory experiments.
Growth rates of Adamsiella chauvinii thalli at the slow-flow site were significantly lower in winter (June) to summer (February) than the intermediate- and fast-flow sites, while in autumn growth rates were similar between sites. However, A. chauvinii at the slow-flow site had similar or higher tissue N content compared to thalli at the other two sites during winter, spring and summer suggesting that growth rates of A. chauvinii were not mass-transfer limited. Nitrogen uptake rates of A. chauvinii were similar between sites in summer and winter, however uptake rates were lower in summer compared to winter even though thalli were nitrogen limited in summer. Water velocity had no effect on nitrate uptake in either summer or winter and uptake of ammonium increased with increasing water velocity during summer only. Two hydrodynamically different environments were distinguished over a canopy of A. chauvinii, with both the laboratory and field velocity profiles in good agreement with each other. In the top half of the canopy, the Turbulent Kinetic Energy (TKE) and Reynolds stresses were greatest while in the bottom half of the canopy flow rates were less than 90 % of mainstream velocity (< 1 cm s⁻�).
When considered together, the influence of water velocity on the growth rates of A. chauvinii was not completely clear. Results suggest that mainstream velocity had little influence on nutrient availability to A. chauvinii because of the unique hydrodynamic environment created by the canopy. Nutrients, especially ammonium and phosphate, derived from the sediment and invertebrates, may provide enough nitrogen and phosphate to saturate the metabolic demand of Adamsiella chauvinii, consequently, A. chauvinii is well adapted to this soft-sediment environment.
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Nascimento, AntÃnia SÃmia Fernandes do. "Lectinas recombinantes das algas marinhas vermelhas Hypnea musciformis (Wulfen) J. V. Lamouroux e Bryothamnion triquetrum (S. G. Gmelin) M. Howe: produÃÃo heterÃloga e caracterizaÃÃo bioquÃmica". Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11322.
Testo completoAbstract (sommario):
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorOs genes sintÃticos das lectinas das algas marinhas vermelhas Hypnea musciformis (HML) e Bryothamnion triquetrum (BTL) foram clonados em diferentes vetores e transformados em diferentes cÃlulas bacterianas de expressÃo. As lectinas recombinantes foram obtidas a partir da fraÃÃo solÃvel das culturas bacterianas de Escherichia coli Rosetta-gami 2 (DE3) para rHML e BL21 (DE3) para rBTL. Os testes de hemaglutinaÃÃo mostraram que rHML e rBTL sÃo capazes de aglutinar eritrÃcitos de coelho tratados com diferentes enzimas proteolÃticas. As propriedades hemaglutinantes de rHML e de rBTL confirmam o enovelamento correto e o estado funcional das proteÃnas. A caracterizaÃÃo da especificidade de ligaÃÃo a carboidratos da HML, BTL e da rBTL por glycan array mostrou uma especificidade restrita por oligossacarÃdeos complexos contendo o nÃcleo de fucosilaÃÃo (α1-6), com uma preferÃncia particular por N-glicanos nÃo bisectados, bi e tri-antenados de cadeia curta. A presenÃa de Ãcido siÃlico na extreminada nÃo-redutora dos glicanos favorece o reconhecimento. Essa foi a primeira caracterizaÃÃo de lectinas de algas vermelhas por glycan array. Experimentos de STD-RMN com a BTL mostraram uma interaÃÃo com um octassacarÃdeo contendo o nÃcleo de fucosilaÃÃo (α1-6). A atividade tÃxica das lectinas selvagens e recombinantes foi avaliada contra Artemia sp. e contra cÃlulas de adenocarcinoma de pulmÃo (A549). Nos ensaios de citotoxicidade, HML, rHML, BTL e rBTL nÃo mostraram nenhuma toxicidade contra Artemia sp. e somente HML e rHML mostraram uma baixa toxicidade contra cÃlulas de adenocarcinoma de pulmÃo (A549). O primeiro cristal de rBTL foi obtido a um nÃvel de microescala com a ajuda de um robÃt de cristalizaÃÃo e difratou a 15 Ã de resoluÃÃo.
Synthetic genes from the red marine algae Hypnea musciformis (HML) and Bryothamnion triquetrum (rBTL) were cloned into differents vectors and transformed into several bacterial expression strains. The recombinant lectins were obtained from the soluble fraction of bacterial cultures using Escherichia coli Rosetta-gami 2 (DE3) strain for rHML and E. coli BL21 (DE3) strain for rBTL. Haemagglutination tests showed that rHML and rBTL are able to agglutinate rabbit erythrocytes with strong haemagglutination activity only after treatment with papain and trysine indicating that their ligands are not directly accessible at the cell surface. The haemagglutinating properties of rHML and rBTL confirm the correct folding and functional state of the proteins. A study of the specificity of these lectins by glycan array was conducted. HML, BTL and rBTL showed a restricted specificity for complex N-glycans with core (α1-6) fucose. A more detailed analysis of the specificity of these lectins showed a preference for non bisecting N-glycans, bi- and tri-antennary branching sugars with short chains. Addition of Sialic acid at the non-reducing end of N-glycans favors their recognition by the lectins. This is the first characterization of lectins from red algae by glycan array. An interaction between BTL and a core (α1-6) fucosylated octasaccharides was also observed by STD-NMR. The toxic activity of wild and recombinant lectins were evaluated against Artemia sp. and the human lung adenocarcinoma cell line (A549). In cytotoxicity assays, HML, rHML, BTL and rBTL showed no toxicity against Artemia sp. Only HML and rHML showed a low cytotoxic activity against cell line (A549). The first crystal of rBTL was obtained in micro-scale level using a robot and diffracted at 15 Ã.
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Kusakariba, Thiago [UNESP]. "Respostas de curto período das características fotossintéticas da alga vermelha Batrachospermum delicatulum a temperatura e irradiância". Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/87876.
Testo completoAbstract (sommario):
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kusakariba_t_me_rcla.pdf: 605912 bytes, checksum: 3bb69f50b5447fd8858f1b6b6d084438 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Respostas de curto período das características fotossintéticas a temperatura e irradiância foram avaliadas na rodófita Batrachospermum delicatulum em condições naturais e em laboratório. A variação diária dos parâmetros fotossintéticos por fluorescência da clorofila foi amostrada em duas épocas (junho, período frio e seco; outubro, quente e chuvoso) em um riacho da região noroeste do Estado de São Paulo (20o43 24-S, 49o18 21-W). Os valores de RQE e RQP (rendimento quântico efetivo e potencial, respectivamente) apresentaram correlação negativa com a irradiância nas duas épocas e valores similares no início e final do dia, indicando respectivamente alta pressão de excitação sobre o fotossistema II (FSII) e boa capacidade de recuperação e ausência de fotodano ao aparato fotossintético. Os valores de NPQ (extinção não-fotoquímica) também apresentaram correlação negativa com irradiância (significativa apenas em junho), o que possivelmente indica baixa capacidade de dissipação da energia absorvida pelos centros de reação. Sob temperatura e irradiância fixas a variação diária para fotossíntese líquida foi caracterizada por dois picos: o primeiro (maior) durante a manhã e o segundo (menor) durante a tarde. Os valores de ETR (taxa de transporte de elétrons) também apresentaram padrão semelhante, o que demonstra a ocorrência de ritmos endógenos que controlam as taxas fotossintéticas. Curvas de fotossíntese-irradiância e de indução escuro/luz foram testadas em laboratório (sob condições de baixa e alta irradiância) e em campo sob luz natural (não-sombreada) e artificialmente sombreada em duas épocas (junho e novembro). O isolado em cultura e as plantas em condições naturais (novembro) tiveram maiores valores de fotossíntese máxima (Fmax), eficiência fotossintética ( ) e rendimento quântico em baixa irradiância...
Short-term responses of photosynthetic characteristics to temperature and irradiance were analyzed in the rhodophyte Batrachospermum delicatulum under natural and laboratory conditions. The diurnal variation of photosynthetic parameters by chlorophyll fluorescence was sampled in two seasons (June, cool and dry season; October, warm and rainy season) in a stream of northwest region of São Paulo state (20o43 24 S, 49o18 21 W). Values of EQY and PQY (effective and potential quantum yield, respectively) were negatively correlated with irradiance in both seasons and had similar values at the beginning and end of the day, indicating, respectively high excitation pressure on photosystem II (PSII) and good recovery capacity and lack of photodamage to the photosynthetic apparatus. Values of NPQ (non-photochemical quenching) were also negatively correlated with irradiance (significantly only in June) possibly indicating low dissipation capacity of absorbed energy by reaction centres. The diurnal variation of net photosynthesis under fixed conditions of temperature and irradiance was characterized by two peaks the first (higher) in the morning and the second (lower) in the afternoon. ETR (electron transport rate) values also presented a similar pattern, suggesting the occurrence of endogenous rhythm that controls photosynthetic rates. Photosynthesis-irradiance and dark/light (induction) curves were tested in laboratory (under low and high irradiance conditions) and in field under natural light (unshaded) and artificially shaded in two seasons (June and November). Specimens from culture isolate and in natural conditions (November) had higher values of maximum photosynthesis (Pmax) photosynthetic efficiency ( ) and EQY at low irradiance, whereas at high irradiance (laboratory and field), values of were significantly higher than at low irradiance. A positive correlation between of ETR with NPQ... (Complete abstract click electronic access below)
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Sundblad, Lars-Göran. "Secondary chlorophyll a luminescence decay kinetics from green algae and higher plants : mechanisms and application". Doctoral thesis, Umeå universitet, Institutionen för fysiologisk botanik, 1988. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-100699.
Testo completoAbstract (sommario):
Barley protoplasts were shown to be a suitable experimental system for studies on the relative maximum during the decay of luminescence observed in most photosynthetic systems after excitation with far red light and in the presence of O2. The far red induced relative luminescence maximum was shown to be a result of three coinciding events: *Randomization of the S-states of the water splitting system during illumination with far red light. *Extreme oxidation of the PSII acceptor side after excitation with far red light and in the presence of O2. *Reverse coupling, causing partial re-reduction of the PSII acceptor side in the dark after far red illumination. When the CO2 concentration in the air above an intact barley leaf was lowered in the dark, the primary PSII acceptor QA was partially reduced. The effect was obtained by changes in CO2 over a wide concentration range including that of saturated photosynthesis. It was thus concluded that the effect was not related to the role of CO2 as the terminal electron acceptor in photosynthesis. White light induced relative maxima during the decay of luminescence frqm low CO2 adapted green algae were shown to be the result of either one or two interacting mechanisms: *Relaxation of qE quenching. *Dark reduction of QA occuring as a result of lowered internal Cj concentration in the dark. Far red induced luminescence decay kinetics and fluorescence induction kinetics, when analyzed with multivariat data analysis, were shown to contain information allowing prediction of the state of frost hardiness in artificially hardened seedlings of Scots pine.Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 8 uppsatser.
digitalisering@umu
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QuinderÃ, Ana Luiza Gomes. "Structural characterization and anti-inflammatory activity in asterosclerose model in mice of a sulfada galactan red algae Acanthophora muscoide". Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13995.
Testo completoAbstract (sommario):
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorConselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Sulfated galactans from red marine algae are polysaccharides with heterogeneous structures that have presented a variety of potentially therapeutic biological effects including anticoagulant, anti-thrombotic and anti-inflammatory, however, their potential activity as anti-inflammatory agent in the treatment of atherosclerosis, a chronic inflammatory disease that culminates with thromboembolic disorders, has not been previously studied. Furthermore, experimental data from animal models and clinical studies support connections between the hemostasis and inflammation in atherogenesis. These interfaces among inflammation and thrombogenesis have been suggested as targets for pharmacological intervention to reduce disease progression. Herein, we determined the chemical structure of a novel sulfated galactan obtained from the marine alga Acanthophora muscoides (fraction AmII) and analysed its effect on a mice model of atherosclerosis in 10-week aged apolipoprotein E deficient (ApoE−/−) mice under high-cholesterol diet for additional 4 or 11 weeks. Fraction AmII (10 mg/kg) or Vehicle were subcutaneously injected from week 2 until 4 of the diet or from week 6 until week 11 of the diet. In vitro assays of macrophage chemotaxis were also performed. The structure of the complex sulfated galactan was characterized by solution nuclear magnetic resonance and its molecular mass was determined by gel permeation chromatography and polyacrylamide gel electrophoresis. The sulfated galactan from A. muscoides presents a molecular mass of ~ 20kDa and an alternating 4-linked α-galactose and 3-linked β-galactose, substituted with sulfate esters and methyl ethers along with the occurrence of 3,6-anhydro-α-galactoses. In the 4 weeks diet model, treatment with fraction AmII did not alter the atherosclerotic plaque size, and other intraplaque features of vulnerability (such as lipid, neutrophil, macrophage, MMP-9 and collagen contents). In the 11 weeks diet model, treatment with fraction AmII reduced intraplaque macrophage and tissue factor (TF) content as compared to Vehicle-treated animals. Intraplaque TF co-localized and positively correlated with macrophage rich-areas. No changes on atherosclerotic plaque size, and other intraplaque features of vulnerability, such as lipid, neutrophil, MMP-9 and collagen contents, were observed. Moreover, mRNA expression of MMPs, chemokines and genetic markers of Th1/2/reg/17 lymphocyte polarization within mouse aortic arches and spleens was not affected by AmII treatment. In vitro, treatment with AmII dose-dependently reduced macrophage chemotaxis without affecting TF production. Overall, the chronic AmII treatment was well tolerated. In conclusion, our results indicate that AmII treatment reduced intraplaque macrophage content, by impacting on cell recruitment, and, concomitantly, intraplaque TF content of potential macrophage origin in atherosclerotic mice.
As galactanas sulfatadas obtidas de algas marinhas vermelhas sÃo polissacarÃdeos de estruturas heterogÃneas que tÃm apresentado uma variedade de efeitos biolÃgicos, potencialmente terapÃuticos, incluindo anticoagulante, antitrombÃtico e anti-inflamatÃrio. No entanto, a sua atividade potencial como agente anti-inflamatÃrio para o tratamento de aterosclerose, uma doenÃa inflamatÃria crÃnica que culmina com distÃrbios tromboembÃlicos, nÃo foi previamente estudada. AlÃm disso, dados experimentais de modelos animais e estudos clÃnicos suportam conexÃes entre a hemostasia e inflamaÃÃo na aterogÃnese. Estas interfaces entre inflamaÃÃo e trombogÃnese tÃm sido sugeridas como alvos para intervenÃÃo farmacolÃgica visando reduzir a progressÃo da doenÃa. No presente trabalho, determinou-se a estrutura quÃmica de uma nova galactana sulfatada obtida da alga marinha Acanthophora muscoides (fraÃÃo AmII) e analisou-se seu efeito sobre um modelo de aterosclerose em camundongos deficientes em apolipoproteÃna E (ApoE−/−) de 10 semanas submetidos a dieta de alto teor de colesterol durante mais 4 ou 11 semanas. A fraÃÃo AmII (10 mg/kg) ou veÃculo (salina) foram injetados por via subcutÃnea durante a segunda atà a quarta semana de dieta ou a partir da sexta atà a dÃcima primeira semana de dieta. Ensaios in vitro de quimiotaxia de macrÃfagos tambÃm foram realizados. A estrutura da galactana sulfatada complexa foi caracterizada por ressonÃncia magnÃtica nuclear em soluÃÃo e a sua massa molecular foi determinada por cromatografia de permeaÃÃo em gel e eletroforese em gel de poliacrilamida. A fraÃÃo AmII apresentou uma massa molecular de ~ 20 kDa e uma alternÃncia de α-galactose 4 ligada e β-galactose 3-ligada, substituÃdo com Ãsteres de sulfato e Ãteres de metil, juntamente com a ocorrÃncia de unidades de 3,6-anidro-α-galactoses. No modelo de dieta de 4 semanas, o tratamento com a fraÃÃo AmII nÃo alteraou o tamanho da placa aterosclerÃtica e demais caracterÃsticas de vulnerabilidade intraplaca, tais como lÃpido, neutrÃfilos, macrÃfagos, metaloprotease de matriz (MMP)-9 e conteÃdo de colÃgeno. No modelo de dieta de 11 semanas, o tratamento com a fraÃÃo AmII reduziu os conteÃdos de macrÃfago intraplaca e de fator tecidual (FT), em comparaÃÃo com animais tratados com veÃculo. O FT intraplaca co-localizou e positivamente correlacionou com Ãreas ricos em macrÃfagos. NÃo foram observadas alteraÃÃes no tamanho da placa aterosclerÃtica e nas outras caracterÃsticas de vulnerabilidade intraplaca, tais como conteÃdos de lipÃdios, neutrÃfilos, MMP-9 e do colÃgeno. AlÃm disso, a expressÃo de mRNA de MMPs, quimiocinas e marcadores genÃticos de polarizaÃÃo de linfÃcitos Th1/2/reg/17 nos arcos aÃrticos e nos baÃos dos camundongos nÃo foi alterada pelo tratamento AmII. In vitro, o tratamento com AmII reduziu de forma dose-dependente a quimiotaxia de macrÃfagos sem afetar a produÃÃo de FT. No geral, o tratamento crÃnico com AmII foi bem tolerado. Em conclusÃo, nossos resultados indicam que o tratamento com AmII em camundongos aterosclerÃticos reduziu o conteÃdo de macrÃfagos intraplaca, agindo sobre o recrutamento celular, e, concomitantemente, o conteÃdo de FT intraplaca de originado potencialmente de macrÃfagos.
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Poulson, Kelsey L. "Sublethal interactions between the harmful alga karenia brevis and its competitors". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49096.
Testo completoAbstract (sommario):
I investigated how competitor species respond to chemical cues released from the red tide dinoflagellate Karenia brevis. K. brevis produces a mix of unstable, relatively polar, allelopathic organic molecules that are produced and released at low concentrations. The production of these compounds also varies greatly within and among strains of K. brevis. The majority of these compounds caused sublethal reductions in competitor growth. In laboratory experiments, these compounds inhibited the growth of competitors Asterionellopsis glacialis, Skeletonema grethae, Prorocentrum minimum, and Akashiwo sanguinea, although each species was susceptible to a different sub-set of K. brevis compounds. Cell physiological state and population densities were important in dictating the susceptibility of competitors to allelopathy: phytoplankton were most susceptible to K. brevis allelopathy when in earlier growth stages (rather than later stages) and in lower cell concentrations. However, these compounds have limited negative effects on natural, mixed populations of competitors from both near and offshore environments, and competitors from inshore and offshore environments appear to respond similarly to K. brevis allelopathy. In the sensitive competitor, Thalassiosira pseudonana, allelopathic compounds ultimately caused a reshuffling of cellular nitrogen pools, altered carbon storage and impaired osmotic regulation as determined using a nuclear magnetic resonance (NMR) based metabolomics approach. By characterizing the pool of primary metabolites present in the cell after exposure to K. brevis cues, we inferred which metabolic pathways may be affected by allelopathy. For instance, concentrations of betaine and the aromatic metabolite homarine were suppressed, indicating that K. brevis allelopathy may disrupt this competitor’s ability to osmoregulate. Exposure to K. brevis cues enhanced the concentrations of glutamate and the fatty acid caprylate/caprate in T. pseudonana, suggesting that protein degradation was enhanced and that energy metabolism was altered. This contrasts with the response to K. brevis allelopathy of the diatom Asterionellopsis glacialis, which was much more resistant to chemical cues produced by K. brevis, likely through as yet unidentified detoxification pathways. Overall, my dissertation research provides insight into how species-specific, antagonistic interactions among phytoplankton competitors can affect community structure through direct or indirect mechanisms, highlights the potential role of allelopathy in the maintenance of K. brevis blooms, and uses a novel tool set (i.e., metabolomics) to determine the molecular targets of K. brevis allelopathy. It further demonstrates that planktonic communities are complex and dynamic ecological systems and that interspecific interactions between phytoplankton can have unexpected, cascading impacts in marine systems.
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Salomaki, Eric D. "A Systematic Investigation of Batrachospermum section Helminthoidea (Batrachospermales, Rhodophyta) Using Molecular and Morphological Analyses". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1343077226.
Testo completo
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Keil, Emily J. "Phylogeography of Batrachospermum gelatinosum (Batrachospermales, Rhodophyta) in Europe". Ohio University Art and Sciences Honors Theses / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors1399043651.
Testo completo
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Yalo, Masande Nicholas. "An investigation of the natural products composition of Porphyra capensis (a red seaweed)". University of the Western Cape, 2017. http://hdl.handle.net/11394/6354.
Testo completoAbstract (sommario):
Magister Scientiae - MSc (Chemistry)Plants have been widely used in traditional medicine for a number of ailments, among which may be included infectious diseases such as colds, influenza, chicken pox, TB, etc. as well as lifestyle diseases such as diabetes and cancer. Seaweeds have also been shown to contribute to the maintenance of health through their nutritional and medicinal properties and recently, a great deal of interest has developed towards the isolation of bioactive compounds from marine sources due to their numerous health benefits. Furthermore, marine algae are valuable sources of structurally diverse metabolites with scientifically proven therapeutic claims. Chemical constituents of red seaweed, Porphyra capensis was investigated in this present study along with subsequent brine shrimp lethality assay analysis of the crude extracts. The compounds isolated from the plant were from the hexane (6) and butanol (2) extracts. These compounds were all isolated and purified by various chromatographic techniques, namely silica gel chromatography, Sephadex LH-20 gel as well as C18 reversed phase silica gel. The structures of the isolated compounds were analysed and characterised by NMR, GC-MS, ESI MS and FTIR spectroscopy. Eight compounds were isolated and identified as phytol, desmosterol, 9-eicosenoic acid, 5,8,11,14,17-eicosapentanoic acid, palmitic acid, methyl (E)-hexadec-9-enoate, glycerol and compound 1 (novel compound). All the compounds were isolated from Porphyra capensis for the first time. The hexane, butanol and methanol extracts were found to be non-toxic with the brine shrimp test LC50 value at least two times greater than ?g/ml.
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Kusakariba, Thiago. "Respostas de curto período das características fotossintéticas da alga vermelha Batrachospermum delicatulum a temperatura e irradiância /". Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/87876.
Testo completoAbstract (sommario):
Orientador: Orlando Necchi JúniorBanca: Ricardo Moreira Chaloub
Banca: Gustavo Habermann
Resumo: Respostas de curto período das características fotossintéticas a temperatura e irradiância foram avaliadas na rodófita Batrachospermum delicatulum em condições naturais e em laboratório. A variação diária dos parâmetros fotossintéticos por fluorescência da clorofila foi amostrada em duas épocas (junho, período frio e seco; outubro, quente e chuvoso) em um riacho da região noroeste do Estado de São Paulo (20o4324-S, 49o1821-W). Os valores de RQE e RQP (rendimento quântico efetivo e potencial, respectivamente) apresentaram correlação negativa com a irradiância nas duas épocas e valores similares no início e final do dia, indicando respectivamente alta pressão de excitação sobre o fotossistema II (FSII) e boa capacidade de recuperação e ausência de fotodano ao aparato fotossintético. Os valores de NPQ (extinção não-fotoquímica) também apresentaram correlação negativa com irradiância (significativa apenas em junho), o que possivelmente indica baixa capacidade de dissipação da energia absorvida pelos centros de reação. Sob temperatura e irradiância fixas a variação diária para fotossíntese líquida foi caracterizada por dois picos: o primeiro (maior) durante a manhã e o segundo (menor) durante a tarde. Os valores de ETR (taxa de transporte de elétrons) também apresentaram padrão semelhante, o que demonstra a ocorrência de ritmos endógenos que controlam as taxas fotossintéticas. Curvas de fotossíntese-irradiância e de indução escuro/luz foram testadas em laboratório (sob condições de baixa e alta irradiância) e em campo sob luz natural (não-sombreada) e artificialmente sombreada em duas épocas (junho e novembro). O isolado em cultura e as plantas em condições naturais (novembro) tiveram maiores valores de fotossíntese máxima (Fmax), eficiência fotossintética ( ) e rendimento quântico em baixa irradiância... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Short-term responses of photosynthetic characteristics to temperature and irradiance were analyzed in the rhodophyte Batrachospermum delicatulum under natural and laboratory conditions. The diurnal variation of photosynthetic parameters by chlorophyll fluorescence was sampled in two seasons (June, cool and dry season; October, warm and rainy season) in a stream of northwest region of São Paulo state (20o4324S, 49o1821W). Values of EQY and PQY (effective and potential quantum yield, respectively) were negatively correlated with irradiance in both seasons and had similar values at the beginning and end of the day, indicating, respectively high excitation pressure on photosystem II (PSII) and good recovery capacity and lack of photodamage to the photosynthetic apparatus. Values of NPQ (non-photochemical quenching) were also negatively correlated with irradiance (significantly only in June) possibly indicating low dissipation capacity of absorbed energy by reaction centres. The diurnal variation of net photosynthesis under fixed conditions of temperature and irradiance was characterized by two peaks the first (higher) in the morning and the second (lower) in the afternoon. ETR (electron transport rate) values also presented a similar pattern, suggesting the occurrence of endogenous rhythm that controls photosynthetic rates. Photosynthesis-irradiance and dark/light (induction) curves were tested in laboratory (under low and high irradiance conditions) and in field under natural light (unshaded) and artificially shaded in two seasons (June and November). Specimens from culture isolate and in natural conditions (November) had higher values of maximum photosynthesis (Pmax) photosynthetic efficiency ( ) and EQY at low irradiance, whereas at high irradiance (laboratory and field), values of were significantly higher than at low irradiance. A positive correlation between of ETR with NPQ... (Complete abstract click electronic access below)
Mestre
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Soutschka, Nadine. "Measuring the growth of the articulated coralline red algae Corrallina officinalis and Arthrocardia corymbosa, (Corallinaceae, Rhodophyta) using a fluorescent brightener". Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/26377.
Testo completoAbstract (sommario):
Coralline algae are important components of the coastal marine ecosystem, making it crucial to understand influences on their production and their growth rate in general. A few attempts have been made to quantify coralline growth rate using various methods, however since they have been reported to be slow growers it is difficult to quantify their growth rate accurately. Calcofluor white is an optical brightener that can be used to stain cell walls of plants and has been used to stain articulated corallines in the field, which proved to be a useful and accurate method for measuring coralline growth rate. This study tested the use of Calcofluor white for measuring growth of articulated (geniculate) coralline algae found on the south-west coast of South Africa, and made a series of methodological tests on the use of the stain. The growth rate of Corallina officinalis and Arthrocardia corymbosa were compared by growing them in culture in aerated plastic bags at 15°C and 16 hr light:8hr dark. Only C. officinalis produced measurable growth in culture (0.08-0.09 mm day⁻¹). Further tests were carried out only on C. officina/is. Additionally, an attempt was made to stain C. officinalis in a rock pool, in situ. In culture, the exposure time to the dye was tested for effect on growth rate. Growth rates were similar after 8 days, but after 20 and 28 days thalli stained for 15 min grew significantly slower than those stained for 5 or 30 min. However, this effect seems to be caused by factors other than staining time (e.g. light or water movement in the culture bags). Growth in culture of C. officinalis was strongly effected by salinity: at 60% saltwater (±21 ppt) growth fell to 0.03 mm day⁻¹ , and there was no growth in 30% saltwater (±10 ppt). The effects of 3 preservation methods on staining in C. officinalis were also tested. The stain was unaffected by drying the thalli or preserving them in 5% formalin in seawater. Preservation in 70% alcohol/20% glycerol/IO% freshwater (a common method of preserving coralline for DNA analysis) reduced stain visibility, particularly when thalli had only been stained for 5 min. The study confirms that Calcofluor white is an effective fluorescent dye for staining coralline red algae. Furthermore, staining can be as short as 5 min and thalli can be preserved without affecting the stain, so that thalli can be stained in situ, preserved, and brought to the laboratory for measurement.