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1.
Bioresour Technol ; 403: 130850, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38759896

ABSTRACT

A practical two-product cascading biorefinery was developed to extract a biostimulant and cellulose from the freshwater filamentous macroalga Oedogonium calcareum grown while treating primary wastewater. Biostimulant production provides a valuable extract with production of disinfected residual biomass for further product development. Both Escherichia coli and F-specific RNA bacteriophage, indicators of human pathogens contamination, were absent from the residual biomass. The chemical composition of the biostimulant was complex, consisting of growth-promoting substances, free amino acids, and minerals. The O. calcareum cellulose fractions yielded between 9.5% and 10.1% (w/w) with purities from 84% to 90% and closely resembled microcrystalline cellulose. Biostimulant extraction improved cellulose quality by increasing crystallinity from 59% to 62%. Biomass condition, drying process, and biostimulant production influenced the crystallinity index. This study demonstrates a two-step process of biostimulant and cellulose extraction from wastewater-grown Oedogonium, simultaneously disinfecting biomass and isolating high-quality cellulose as a sustainable alternative to conventional extraction methods.


Subject(s)
Biomass , Cellulose , Wastewater , Water Purification , Cellulose/chemistry , Wastewater/chemistry , Water Purification/methods , Chlorophyta/metabolism , Chlorophyta/chemistry
2.
Carbohydr Polym ; 333: 121962, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38494219

ABSTRACT

Ulva are hardy green seaweeds that contain the sulfated polysaccharide ulvan and grow in two distinct morphologies: foliose and tubular. The authors hypothesise that ulvan from tubular species are more structurally complex than ulvans from foliose species. Herein, using standardised methods, the glycosyl linkage positions and sulfate ester substitutions of constituent monosaccharides of ulvan isolated from foliose (U. lacinulata and U. stenophylloides) and tubular (U. prolifera and U. ralfsii) species of Ulva were investigated. Comparison of native ulvans with 80 and 100 °C desulfated counterparts indicated that 4-linked rhamnose is predominantly 3-O-sulfated in all four ulvans. Ulvans from the foliose species predominantly contained →3,4)-Rhap-(1→, →4)-GlcAp-(1→ and →4)-IdoAp-(1→, collectively accounting for 67 to 81 mol% of the total linkages. In contrast, these same linkages in ulvans from the tubular species only collectively accounted for 29 to 36 mol%. Instead, ulvan from tubular species contained a combination of →2,3,4)-Rhap-(1→, terminal Rhap-(1→, →4)-GlcAp-(1→, →4)-Xylp-(1→, and/or →4)-Galp-(1→ in high proportions; some of the latter three residues were also likely O-2 sulfated. The results presented here suggest that ulvan from foliose species are predominantly unbranched polysaccharides composed of repeat disaccharides while ulvans from tubular species contain a greater diversity of branch and sulfate substitution locations.


Subject(s)
Seaweed , Ulva , Ulva/chemistry , Polysaccharides/chemistry , Sulfates/chemistry
3.
J Appl Phycol ; : 1-14, 2023 Apr 28.
Article in English | MEDLINE | ID: mdl-37360290

ABSTRACT

The biomass composition of kelp varies within species both spatially and temporally. However, this variation in biomass quality has not yet been investigated for the native kelp Ecklonia radiata within New Zealand, where the kelp is a target for the emerging seaweed aquaculture industry. In this study we quantified spatial and temporal variation in the composition of E. radiata biomass, collected from 12 sites around the North Island of New Zealand and from 12 months across a full year at a single site (n = 138). High spatial variation was detected for most components, including alginate (range: 16.6 - 22.7% DW, n = 12), fucoidan (range: 1.2 - 1.6% DW, n = 12), phlorotannins (range: 4.8 - 9.3% DW, n = 72), and glucose (range: 9.3 - 22.6% DW, n = 12). The biomass composition of E. radiata varied significantly among sites but with no clear patterns among regions, indicating that geographic differences were mostly local rather than regional, possibly due to site-specific environmental conditions. Significant temporal variation (measured by positive autocorrelation between months) was detected in the content of lipids, proteins, glucose, guluronic acid, nitrogen, phosphorous, iodine, arsenic, and mercury, and for the mannuronic to guluronic acid (M:G) ratio. Overall, E. radiata had comparable biomass composition to that of commercially grown northern hemisphere species but with substantially higher phlorotannin content. These results demonstrate that E. radiata could be a viable southern hemisphere alternative for a broad range of commercial applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s10811-023-02969-2.

4.
Int J Mol Sci ; 23(22)2022 Nov 09.
Article in English | MEDLINE | ID: mdl-36430290

ABSTRACT

Macroalgae produce compounds with industrial, pharmaceutical and nutritional applications. In this study, biomass from the freshwater macroalgal genus Oedogonium was grown in either treated municipal wastewater (M) or ash dam water from a coal-fired power station (D). The biomass was investigated for its metabolic responses in high-carbohydrate, high-fat diet-fed rats, a model of human metabolic syndrome. The Oedogonium biomass cultured in M contained higher amounts of K, Mg, omega-3 polyunsaturated fatty acids (PUFA), insoluble fibre and ß-carotene, while biomass grown in D contained higher amounts of Al, Fe, V, Zn, Mn and As. Biomass from M further increased body weight and inflammation in the heart and colon in high-carbohydrate, high-fat diet-fed rats. In contrast, biomass from D prevented changes in metabolic, cardiovascular and liver parameters without changing tissue histology. We suggest that increased intake of metals and metalloids through macroalgal biomass from D may decrease abdominal fat deposition while polysaccharides, PUFA and carotenoids from M may improve blood glucose responses in an obesogenic diet. Thus, macroalgal biomass grown in different wastewater sources could be acceptable for feed or food applications. This biomass could even provide potential health benefits in diet-induced metabolic syndrome.


Subject(s)
Chlorophyceae , Metabolic Syndrome , Seaweed , Humans , Rats , Animals , Metabolic Syndrome/etiology , Wastewater , Fresh Water , Diet, High-Fat/adverse effects , Carbohydrates
5.
Foods ; 11(4)2022 Feb 16.
Article in English | MEDLINE | ID: mdl-35206042

ABSTRACT

The intestinal microbial community (microbiota) is dynamic and variable amongst individuals and plays an essential part in gut health and homeostasis. Dietary components can modulate the structure of the gut microbiota. In recent years, substantial efforts have been made to find novel dietary components with positive effects on the gut microbial community structure. Natural algal polysaccharides and carotenoids have been reported to possess various functions of biological relevance and their impact on the gut microbiota is currently a topic of interest. This study, therefore, reports the effect of the sulfated polysaccharide ulvan and the carotenoid astaxanthin extracted and purified from the aquacultured marine green macroalgae Ulva ohnoi and freshwater green microalgae Haematococcus pluvialis, respectively, on the temporal development of the murine gut microbiota. Significant changes with the increase in the bacterial classes Bacteroidia, Bacilli, Clostridia, and Verrucomicrobia were observed after feeding the mice with ulvan and astaxanthin. Duration of the treatments had a more substantial effect on the bacterial community structure than the type of treatment. Our findings highlight the potential of ulvan and astaxanthin to mediate aspects of host-microbe symbiosis in the gut, and if incorporated into the diet, these could assist positively in improving disease conditions associated with gut health.

6.
Int J Biol Macromol ; 194: 571-579, 2022 Jan 01.
Article in English | MEDLINE | ID: mdl-34813787

ABSTRACT

Ulvans from Ulva ohnoi, Ulva tepida and Ulva prolifera were extracted under mild acidic conditions, isolated and their composition and structure determined. The ulvans contained mostly rhamnose (31.6-46.7 mol%) and glucuronic acid (26.6-37.5 mol%), with smaller amounts of xylose (3.4-10.4 mol%) and iduronic acid (3.1-7.6 mol%). In addition, the ulvan samples also contained galactose (4.4-26.0 mol%). Glycosyl linkage analysis showed that ulvan from U. ohnoi contained mostly →4)-GlcpA-(1→ and →3,4)-Rhap-(1→. Preparation of partially methylated alditol acetate standards of idose showed that U. ohnoi contained →4)-IdopA-(1→. In addition to these residues, glycosyl linkage analysis of U. tepida and U. prolifera showed the presence of →2,3,4)-Rhap-(1→, →4)-Xylp-(1→, →2,4)-GlcpA-(1→ and →3,4)-GlcpA-(1→. These two species also contained galactose linkages. These data, together with nuclear magnetic resonance (NMR) spectroscopy indicated that U. ohnoi comprised mostly of type A3S ulvanobiuronic acid repeats [→4)-ß-D-GlcpA-(1→4)-α-L-Rhap3S-(1→], together with smaller amounts of type B3S ulvanobiuronic acid repeats [→4)-α-L-IdopA-(1→4)-α-L-Rhap3S-(1→] and ulvanobiose (U3S [→4)-ß-D-Xylp-(1→4)-α-L-Rhap3S-(1→]). NMR spectra of U. tepida and U. prolifera showed resonances not detected in U. ohnoi, highlighting the complexity of the ulvans from these species. Regardless of the structural diversity of the ulvan samples there was very little antioxidant or inhibitory activity detected on enzymatic processes investigated.


Subject(s)
Polysaccharides/chemistry , Ulva/metabolism , Antioxidants/chemistry , Molecular Structure
7.
Nutrients ; 13(6)2021 May 21.
Article in English | MEDLINE | ID: mdl-34064139

ABSTRACT

The therapeutic potential of Sargassum siliquosum grown in Australian tropical waters was tested in a rat model of metabolic syndrome. Forty-eight male Wistar rats were divided into four groups of 12 rats and each group was fed a different diet for 16 weeks: corn starch diet (C); high-carbohydrate, high-fat diet (H) containing fructose, sucrose, saturated and trans fats; and C or H diets with 5% S. siliquosum mixed into the food from weeks 9 to 16 (CS and HS). Obesity, hypertension, dyslipidaemia, impaired glucose tolerance, fatty liver and left ventricular fibrosis developed in H rats. In HS rats, S. siliquosum decreased body weight (H, 547 ± 14; HS, 490 ± 16 g), fat mass (H, 248 ± 27; HS, 193 ± 19 g), abdominal fat deposition and liver fat vacuole size but did not reverse cardiovascular and liver effects. H rats showed marked changes in gut microbiota compared to C rats, while S. siliquosum supplementation increased gut microbiota belonging to the family Muribaculaceae. This selective increase in gut microbiota likely complements the prebiotic actions of the alginates. Thus, S. siliquosum may be a useful dietary additive to decrease abdominal and liver fat deposition.


Subject(s)
Dietary Supplements , Metabolic Syndrome/therapy , Obesity/therapy , Sargassum , Seaweed/microbiology , Abdominal Fat/microbiology , Animals , Body Weight/physiology , Diet/adverse effects , Disease Models, Animal , Gastrointestinal Microbiome/physiology , Liver/microbiology , Male , Metabolic Syndrome/etiology , Metabolic Syndrome/microbiology , Obesity/etiology , Obesity/microbiology , Prebiotics/microbiology , Rats , Rats, Wistar
8.
Carbohydr Polym ; 264: 118010, 2021 Jul 15.
Article in English | MEDLINE | ID: mdl-33910714

ABSTRACT

Green seaweeds of the genus Ulva are rich in the bioactive sulfated polysaccharide ulvan. Herein we characterise ulvan from Ulva species collected from the Bay of Plenty, Aotearoa New Zealand. Using standardised procedures, we quantified, characterised, and compared ulvans from blade (U. australis, U. rigida, U. sp. B, and Ulva sp.) and filamentous (U. flexuosa, U. compressa, U. prolifera, and U. ralfsii) Ulva species. There were distinct differences in composition and structure of ulvans between morphologies. Ulvan isolated from blade species had higher yields (14.0-19.3 %) and iduronic acid content (IdoA = 7-18 mol%), and lower molecular weight (Mw = 190-254 kDa) and storage moduli (G' = 0.1-6.6 Pa) than filamentous species (yield = 7.2-14.6 %; IdoA = 4-7 mol%; Mw = 260-406 kDa; G' = 22.7-74.2 Pa). These results highlight the variability of the physicochemical properties of ulvan from different Ulva sources, and identifies a morphology-based division within the genus Ulva.


Subject(s)
Polysaccharides/chemistry , Seaweed/chemistry , Ulva/chemistry , Cell Wall/chemistry , Iduronic Acid/analysis , Molecular Weight , Multivariate Analysis , New Zealand , Polysaccharides/isolation & purification , Rheology/methods , Spectroscopy, Fourier Transform Infrared/methods , Sulfates/chemistry
9.
Int J Biol Macromol ; 150: 839-848, 2020 May 01.
Article in English | MEDLINE | ID: mdl-32057850

ABSTRACT

Ulvan, a sulfated polysaccharide extracted from the green seaweed genus Ulva, has bioactive properties including an immunomodulating capacity. The immunomodulatory capacity of ulvan from Ulva ohnoi, however, has not been assessed in detail. We depolymerised purified ulvan from U. ohnoi to obtain a range of molecular weight fractions (Mw 7, 9, 13, 21, 209 kDa), which were characterised by constituent sugar analysis, SEC-MALLS, and NMR. Ulvan fractions contained 48.8-54.7 mol% rhamnose, 32.5-35.9 mol% glucuronic acid, 4.5-7.3 mol% iduronic acid, and 3.3-5.6 mol% xylose. 1H and 13C NMR was consistent with hydrolysis occurring at the anomeric centre without further modification to the oligosaccharide structure. The in vitro immunomodulatory effect of ulvan fractions was quantified by measuring levels of inflammatory-mediating signalling molecules released from LPS-stimulated RAW264.7 murine macrophages. All ulvan fractions showed no toxicity on RAW264.7 cells at concentrations below 100 µg mL-1 over 48 h. Secreted interleukin-10 and prostaglandin E2 demonstrated an anti-inflammatory effect by higher molecular weight ulvan fractions at 100 µg mL-1. To a lesser extent, these fractions also enhanced the LPS-induced inflammation through minor increases of IL-1ß and IL-6. This study confirms that ulvan from U. ohnoi has a mild in vitro immunomodulatory effect.


Subject(s)
Macrophages/drug effects , Polysaccharides/chemistry , Polysaccharides/pharmacology , Ulva/chemistry , Animals , Cell Survival/drug effects , Glucuronic Acid , Iduronic Acid , Immunologic Factors/pharmacology , Interleukin-1beta , Interleukin-6 , Lipopolysaccharides/adverse effects , Mice , Molecular Weight , Peptide Fragments , RAW 264.7 Cells , Rhamnose , Seaweed/chemistry , Xylose
10.
Microb Ecol ; 75(3): 811-818, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29018917

ABSTRACT

The red macroalga Asparagopsis taxiformis has been shown to significantly decrease methane production by rumen microbial communities. This has been attributed to the bioaccumulation of halogenated methane analogues produced as algal secondary metabolites. The objective of this study was to evaluate the impact of A. taxiformis supplementation on the relative abundance of methanogens and microbial community structure during in vitro batch fermentation. Addition of A. taxiformis (2% organic matter) or the halogenated methane analogue bromoform (5 µM) reduced methane production by over 99% compared to a basal substrate-only control. Quantitative PCR confirmed that the decrease in methane production was correlated with a decrease in the relative abundance of methanogens. High-throughput 16S ribosomal RNA gene amplicon sequencing showed that both treatments reduced the abundance of the three main orders of methanogens present in ruminants (Methanobacteriales, Methanomassiliicoccales and Methanomicrobiales). Shifts in bacterial community structure due to the addition of A. taxiformis and 5 µM bromoform were similar and concomitant with increases in hydrogen concentration in the headspace of the fermenters. With high potency and broad-spectrum activity against rumen methanogens, A. taxiformis represents a promising natural strategy for reducing enteric methane emissions from ruminant livestock.


Subject(s)
Methane/analogs & derivatives , Microbiota/drug effects , Rhodophyta/metabolism , Rumen/microbiology , Seaweed/metabolism , Animals , Bacteria/classification , Bacteria/drug effects , Bacteria/metabolism , DNA, Bacterial/genetics , Fermentation , Halogenation , Hydrogen/metabolism , In Vitro Techniques , Livestock/microbiology , Methane/metabolism , Methanobacteriales/drug effects , Methanobacteriales/metabolism , Methanomicrobiales/drug effects , Methanomicrobiales/metabolism , Microbiota/genetics , RNA, Ribosomal, 16S/genetics , Trihalomethanes/pharmacology
11.
Nutrients ; 7(4): 2771-87, 2015 Apr 14.
Article in English | MEDLINE | ID: mdl-25875119

ABSTRACT

This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC) containing protein (46.1% of dry algae), insoluble fibre (19.6% of dry algae), minerals (3.7% of dry algae) and omega-3 fatty acids (2.8% of dry algae) as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharides, while the other two groups were fed a diet high in simple carbohydrates (fructose and sucrose in food, 25% fructose in drinking water, total 68%) and fats (saturated and trans fats from beef tallow, total 24%). High carbohydrate, high fat-fed rats showed visceral obesity with hypertension, insulin resistance, cardiovascular remodelling, and nonalcoholic fatty liver disease. SC supplementation (5% of food) lowered total body and abdominal fat mass, increased lean mass, and attenuated hypertension, impaired glucose and insulin tolerance, endothelial dysfunction, infiltration of inflammatory cells into heart and liver, fibrosis, increased cardiac stiffness, and nonalcoholic fatty liver disease in the high carbohydrate, high fat diet-fed rats. This study suggests that the insoluble fibre or protein in SC helps reverse diet-induced metabolic syndrome.


Subject(s)
Anti-Obesity Agents/administration & dosage , Chlorophyta , Dietary Supplements , Metabolic Syndrome/drug therapy , Obesity, Abdominal/drug therapy , Scenedesmus , Animals , Blood Glucose/metabolism , Body Composition , Cardiovascular Diseases/drug therapy , Cholesterol/blood , Diet, High-Fat/adverse effects , Dietary Carbohydrates/administration & dosage , Dietary Fats/administration & dosage , Dietary Fiber/administration & dosage , Fatty Acids, Omega-3/administration & dosage , Fructose/administration & dosage , Glucose Tolerance Test , Hypertension/drug therapy , Insulin/blood , Insulin Resistance , Magnesium/administration & dosage , Magnesium/blood , Male , Non-alcoholic Fatty Liver Disease/drug therapy , Organ Size , Potassium, Dietary/administration & dosage , Potassium, Dietary/blood , Rats , Rats, Wistar , Sodium, Dietary/administration & dosage , Sodium, Dietary/blood , Sucrose/administration & dosage , Triglycerides/blood
12.
Mar Drugs ; 13(2): 788-805, 2015 Feb 02.
Article in English | MEDLINE | ID: mdl-25648511

ABSTRACT

Increased seaweed consumption may be linked to the lower incidence of metabolic syndrome in eastern Asia. This study investigated the responses to two tropical green seaweeds, Ulva ohnoi (UO) and Derbesia tenuissima (DT), in a rat model of human metabolic syndrome. Male Wistar rats (330-340 g) were fed either a corn starch-rich diet or a high-carbohydrate, high-fat diet with 25% fructose in drinking water, for 16 weeks. High-carbohydrate, high-fat diet-fed rats showed the signs of metabolic syndrome leading to abdominal obesity, cardiovascular remodelling and non-alcoholic fatty liver disease. Food was supplemented with 5% dried UO or DT for the final 8 weeks only. UO lowered total final body fat mass by 24%, systolic blood pressure by 29 mmHg, and improved glucose utilisation and insulin sensitivity. In contrast, DT did not change total body fat mass but decreased plasma triglycerides by 38% and total cholesterol by 17%. UO contained 18.1% soluble fibre as part of 40.9% total fibre, and increased magnesium, while DT contained 23.4% total fibre, essentially as insoluble fibre. UO was more effective in reducing metabolic syndrome than DT, possibly due to the increased intake of soluble fibre and magnesium.


Subject(s)
Cardiovascular System/drug effects , Diet, High-Fat/adverse effects , Dietary Supplements , Hemodynamics/drug effects , Liver/drug effects , Metabolism/drug effects , Seaweed/chemistry , Animals , Blood Chemical Analysis , Diet , Male , Metabolic Syndrome/prevention & control , Non-alcoholic Fatty Liver Disease/prevention & control , Obesity, Abdominal/prevention & control , Organ Size/drug effects , Rats , Rats, Wistar
13.
Mar Biotechnol (NY) ; 16(4): 456-64, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24510373

ABSTRACT

Biomass productivity was quantified for the marine macroalga Derbesia tenuissima cultivated outdoors at seven stocking densities from 0.25 to 8 g L(-1) for 5 weeks. Total lipids and fatty acid quantity and quality was measured from samples that were freeze-dried, dried by oven (75 °C), food dehydrator (60 °C), or outdoor in the sun (40 °C) or shade (38 °C). Stocking densities of 0.25 to 2 g L(-1) yielded the highest biomass productivities (>20 g dry weight m(-2) day(-1)) with no effect on total lipid quantity (11 %), or fatty acid quantity (5.3 %) or quality at any density tested. However, there was an interactive effect of stocking density and drying technique, with a decrease of up to 40 % in polyunsaturated fatty acids in sun-dried compared to freeze-dried biomass. Notably, while fatty acid and biomass productivity may be inseparable in macroalgae, cultivation conditions have a significant carryover effect in the post-harvest delivery of high-quality bio-oils.


Subject(s)
Batch Cell Culture Techniques/methods , Biofuels/microbiology , Bioreactors/microbiology , Fatty Acids/metabolism , Lipid Metabolism/physiology , Seaweed/physiology , Cell Proliferation/physiology , Chlorophyta/cytology , Chlorophyta/physiology , Seaweed/cytology
14.
PLoS One ; 9(1): e85289, 2014.
Article in English | MEDLINE | ID: mdl-24465524

ABSTRACT

This study aimed to evaluate the effects of twenty species of tropical macroalgae on in vitro fermentation parameters, total gas production (TGP) and methane (CH4) production when incubated in rumen fluid from cattle fed a low quality roughage diet. Primary biochemical parameters of macroalgae were characterized and included proximate, elemental, and fatty acid (FAME) analysis. Macroalgae and the control, decorticated cottonseed meal (DCS), were incubated in vitro for 72 h, where gas production was continuously monitored. Post-fermentation parameters, including CH4 production, pH, ammonia, apparent organic matter degradability (OMd), and volatile fatty acid (VFA) concentrations were measured. All species of macroalgae had lower TGP and CH4 production than DCS. Dictyota and Asparagopsis had the strongest effects, inhibiting TGP by 53.2% and 61.8%, and CH4 production by 92.2% and 98.9% after 72 h, respectively. Both species also resulted in the lowest total VFA concentration, and the highest molar concentration of propionate among all species analysed, indicating that anaerobic fermentation was affected. Overall, there were no strong relationships between TGP or CH4 production and the >70 biochemical parameters analysed. However, zinc concentrations >0.10 g x kg(-1) may potentially interact with other biochemical components to influence TGP and CH4 production. The lack of relationship between the primary biochemistry of species and gas parameters suggests that significant decreases in TGP and CH4 production are associated with secondary metabolites produced by effective macroalgae. The most effective species, Asparagopsis, offers the most promising alternative for mitigation of enteric CH4 emissions.


Subject(s)
Fermentation , Gases/metabolism , Methane/metabolism , Seaweed/metabolism , Algorithms , Ammonia/metabolism , Animals , Body Fluids/metabolism , Cattle , Fatty Acids, Volatile/metabolism , Fresh Water , Geography , Hydrogen-Ion Concentration , Models, Biological , Queensland , Rumen/metabolism , Seawater , Seaweed/classification , Time Factors
15.
Water Res ; 47(14): 5211-21, 2013 Sep 15.
Article in English | MEDLINE | ID: mdl-23870432

ABSTRACT

Many organic compounds including some herbicides concentrate in sediment, thus it may be expected that interstitial waters contain higher concentrations of these contaminants than the water column. To estimate benthic microalgal exposure to pesticides, sediment and interstitial water sampled in the dry season from four major rivers in north Queensland, Australia, were analysed for these contaminants. Interstitial water extracts from the sediments were tested for acute phytotoxicity to benthic microalgae using PAM fluorometry and the results were compared with chemical analyses of the same water samples. A range of pesticides were detected in both sediment and interstitial waters from all sites, notably the herbicide diuron at concentrations ranging from 0.3 to 11 µg kg(-1) dry weight sediment, and up to 68 ng L(-1) in interstitial waters. Herbicide concentrations estimated from partition coefficients and the sediment concentrations typically overestimated analytically determined concentrations present in interstitial water by an order of magnitude. The analytically determined herbicide concentrations in the interstitial water explained most of the phytotoxicity measured with the bioassay; however, photoinhibition was slightly higher than expected based on analytical results, indicating the presence of unidentified phytotoxins. These results demonstrate the presence of pesticides in interstitial waters in the Tropical dry season, sometimes at concentrations that may affect sensitive benthic organisms, and supports the use of the I-PAM bioassay as a valuable tool in exposure- and environmental risk- and impact-assessments.


Subject(s)
Microalgae/drug effects , Pesticides/analysis , Pesticides/toxicity , Water Pollutants, Chemical/toxicity , Diuron/analysis , Diuron/toxicity , Environmental Monitoring/methods , Geologic Sediments/analysis , Queensland , Rivers , Toxicity Tests, Acute/methods , Water Pollutants, Chemical/analysis
16.
PLoS One ; 8(5): e63569, 2013.
Article in English | MEDLINE | ID: mdl-23667639

ABSTRACT

Microalgae are ideal candidates for waste-gas and -water remediation. However, salinity often varies between different sites. A cosmopolitan microalga with large salinity tolerance and consistent biochemical profiles would be ideal for standardised cultivation across various remediation sites. The aims of this study were to determine the effects of salinity on Picochlorum atomus growth, biomass productivity, nutrient uptake and biochemical profiles. To determine if target end-products could be manipulated, the effects of 4-day nutrient limitation were also determined. Culture salinity had no effect on growth, biomass productivity, phosphate, nitrate and total nitrogen uptake at 2, 8, 18, 28 and 36 ppt. 11 ppt, however, initiated a significantly higher total nitrogen uptake. While salinity had only minor effects on biochemical composition, nutrient depletion was a major driver for changes in biomass quality, leading to significant increases in total lipid, fatty acid and carbohydrate quantities. Fatty acid composition was also significantly affected by nutrient depletion, with an increased proportion of saturated and mono-unsaturated fatty acids. Having established that P. atomus is a euryhaline microalga, the effects of culture salinity on the development of the freshwater cyanobacterial contaminant Pseudanabaena limnetica were determined. Salinity at 28 and 36 ppt significantly inhibited establishment of P. limnetica in P. atomus cultures. In conclusion, P. atomus can be deployed for bioremediation at sites with highly variable salinities without effects on end-product potential. Nutrient status critically affected biochemical profiles--an important consideration for end-product development by microalgal industries. 28 and 36 ppt slow the establishment of the freshwater cyanobacterium P. limnetica, allowing for harvest of low contaminant containing biomass.


Subject(s)
Chlorophyta/physiology , Cyanobacteria/growth & development , Fresh Water/microbiology , Salinity , Salt Tolerance/physiology , Biodegradation, Environmental , Biomass , Carbohydrate Metabolism , Chlorophyta/growth & development , Esters/metabolism , Fatty Acids/metabolism , Microalgae/growth & development , Microalgae/physiology , Nitrates/metabolism , Nitrites/metabolism , Nitrogen/metabolism , Phosphates/metabolism , Proteins/metabolism
17.
Bioresour Technol ; 131: 113-20, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23340108

ABSTRACT

Land-based aquaculture produces suspended solids in culture pond and settlement pond waters that could be harvested as a bioresource. Suspended solids were quantified, characterised and harvested from these two sources to assess their suitability for conversion to bioproducts. The suspended solids of settlement ponds were less concentrated (87.6±24.7mgL(-1)) than those of culture ponds (131.8±8.8mgL(-1)), but had a higher concentration of microalgae (27.5±4.0%) and consequently higher particulate organic carbon (24.8±4.7%) and particulate nitrogen (4.0±0.8%). The microalgal community also differed between sources with a higher concentration of fatty acids in the biomass from settlement ponds. Consequently, biochar produced from biomass harvested from settlement ponds was higher in organic carbon and nitrogen, with a lower cation exchange capacity. In conclusion, we characterised a renewable and potentially valuable bioresource for algal bioproducts derived from suspended solids in intensive land-based aquaculture.


Subject(s)
Aquaculture/methods , Carbon/isolation & purification , Carbon/metabolism , Microalgae/metabolism , Microbial Consortia/physiology , Nitrogen/isolation & purification , Nitrogen/metabolism , Microalgae/classification , Species Specificity , Suspensions
18.
Mar Pollut Bull ; 65(4-9): 363-72, 2012.
Article in English | MEDLINE | ID: mdl-22019103

ABSTRACT

The effects of prolonged exposure to low concentrations of herbicides on tropical periphyton (biofilm) communities are largely unknown. Tropical estuarine biofilms established in microcosms were therefore exposed to diuron (photosystem-II-inhibitor) at 2-16µg L(-1) for 4 weeks. The biofilms, consisting of diatoms, filamentous brown algae and cyanobacteria, developed a tolerance to diuron during this period as measured by Phyto-PAM fluorometry. Microscopy and pigment analysis revealed that this decrease in sensitivity was accompanied by a shift in species composition towards communities dominated by diatoms. The combination of techniques enabled the first identification of pollution-induced community tolerance (PICT) in tropical estuarine periphyton in response to chronic herbicide exposures. Community composition changed compared to controls at environmentally relevant concentrations of 1.6µg L(-1), while development of PICT was evident at 6.5µg L(-1) diuron, with no recovery (over 2 weeks) in uncontaminated water, indicating chronic pollution induced shifts in community structure.


Subject(s)
Diuron/toxicity , Herbicides/toxicity , Water Pollutants, Chemical/toxicity , Biodiversity , Biofilms , Cyanobacteria/drug effects , Cyanobacteria/physiology , Diatoms/drug effects , Diatoms/physiology , Environmental Monitoring , Phaeophyceae/drug effects , Phaeophyceae/physiology , Photosynthesis , Tropical Climate
19.
Mar Pollut Bull ; 60(11): 1978-87, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20800855

ABSTRACT

Natural waters often contain complex mixtures of unknown contaminants potentially posing a threat to marine communities through chemical interactions. Here, acute effects of the photosystem II-inhibiting herbicides diuron, tebuthiuron, atrazine, simazine, and hexazinone, herbicide breakdown products (desethyl-atrazine (DEA) and 3,4-dichloroaniline (3,4-DCA)) and binary mixtures, were investigated using three tropical benthic microalgae; Navicula sp. and Cylindrotheca closterium (Ochrophyta) and Nephroselmis pyriformis (Chlorophyta), and one standard test species, Phaeodactylum tricornutum (Ochrophyta), in a high-throughput Maxi-Imaging-PAM bioassay (Maxi-IPAM). The order of toxicity was; diuron > hexazinone > tebuthiuron > atrazine > simazine > DEA > 3,4-DCA for all species. The tropical green alga N. pyriformis was up to 10-fold more sensitive than the diatoms tested here and reported for coral symbionts, and is recommended as a standard tropical test species for future research. All binary mixtures exhibited additive toxicity, and the use of herbicide equivalents (HEq) is therefore recommended in order to incorporate total-maximum-load measures for environmental regulatory purposes.


Subject(s)
Chlorophyta , Diatoms , Herbicides/toxicity , Water Pollutants, Chemical/toxicity , Biological Assay , Environmental Policy , Tropical Climate
20.
Eur J Cancer ; 45(14): 2488-95, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19540105

ABSTRACT

BACKGROUND: A previous study has shown that pentoxifylline in combination with vitamin E can reverse radiation-induced fibrosis. The aim of the present study is to investigate if the same drugs could prevent radiation-induced side-effects in women with breast cancer. PATIENTS AND METHODS: A randomised, placebo-controlled, double-blind, parallel group trial was performed. Women with breast cancer were treated for 12 months with 400 mg pentoxifylline t.i.d. or placebo, in combination with 100 mg vitamin E t.i.d., starting 1-3 months after the completion of radiotherapy. The primary end-point was passive abduction of the shoulder, and the secondary end-point was difference in arm volumes. The trial is registered on the ISRCTN.org website, number ISRCTN39143623. RESULTS: 83 patients were included in the study; 42 in the pentoxifylline+vitamin E group and 41 in the placebo+vitamin E group. Both treatments were generally well tolerated. Seven patients were withdrawn from the treatment due to disease progression; four in the pentoxifylline group and three in the placebo group. At inclusion, patients had impaired passive abduction of the shoulder. During treatment, both the groups improved significantly. Median improvement from baseline was 3.7 degrees (p=0.0035) on pentoxifylline and was 9.4 degrees (p=0.0041) in the placebo group, but no difference between the groups was detected (p=0.20). Arm volumes increased over time in the placebo group (1.04%), but not on pentoxifylline (0.50%), and differed significantly between the groups (p=0.0172). CONCLUSIONS: The combination of pentoxifylline and vitamin E was safe and may be used for the prevention of some radiation-induced side-effects.


Subject(s)
Antioxidants/therapeutic use , Breast Neoplasms/radiotherapy , Pentoxifylline/therapeutic use , Radiation Injuries/prevention & control , Radiation-Protective Agents/therapeutic use , Vitamin E/therapeutic use , Aged , Double-Blind Method , Drug Therapy, Combination , Female , Humans , Middle Aged , Radiotherapy Dosage , Radiotherapy, Adjuvant/adverse effects , Sweden , Treatment Outcome
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