Prey preference, environmental tolerances and ichthyotoxicity by the red-tide dinoflagellate Noctiluca scintillans cultured from Tasmanian waters

2019 ◽  
Vol 41 (4) ◽  
pp. 407-418 ◽  
Author(s):  
Gustaaf M Hallegraeff ◽  
Maria E Albinsson ◽  
Jo Dowdney ◽  
Angela K Holmes ◽  
Maged P Mansour ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Growth Rates ◽  
Red Tide ◽  
Optimal Growth ◽  
Noctiluca Scintillans ◽  
Grazing Impacts ◽  
Beach Tourism ◽  
Key Factor ◽  
Unionized Ammonia ◽  
Culture Growth

Abstract The large phagotrophic dinoflagellate Noctiluca has become a prominent red tide organism in southeast Australian waters since the 2000s, raising concerns for beach tourism, grazing impacts as well as ichthyotoxicity for finfish aquaculture. Satisfactory culture growth rates (0.23–0.56 per day) were obtained by feeding with small Thalassiosira diatom and Tetraselmis flagellate diets, while optimal growth rates sustained for up to 8 months (0.69 per day) were achieved by feeding in a plankton wheel with the large chain-forming dinoflagellate Gymnodinium catenatum. Noctiluca was highly tolerant towards salinities from 20 to 35 and growth was stimulated by temperatures increasing from 10 to 23°C, which in combination with the key factor of prey abundance explains the incidence in southeast Australia of predominantly summer and spring but occasionally also winter blooms. Fatty acid biomarkers suggest that Tasmanian field populations indiscriminately feed on available diatom and dinoflagellate mixtures. Noctiluca exhibited very limited ichthyotoxicity, and only at the highest cell concentrations of 2 000 000/L (50% reduction in RTgill W1 cell viability). Only the densest red tide surface slicks contained acutely toxic levels of unionized ammonia of 242 to 510 μg/L while inshore slicks generated oxygen concentrations as low as 0–1.5 ppm. Lipid phycotoxins (eicosapentaenoic acid, docosahexaenoic acid) did not appear to contribute to Noctiluca ichthyotoxicity. The fatty acid 20:0 eicosanoic acid may serve as a potential Noctiluca biomarker in marine food webs and sediments.

scholarly journals Active reconfiguration of cytoplasmic lipid droplets governs migration of nutrient-limited phytoplankton

2021 ◽  
Author(s):  
Anupam Sengupta ◽  
Jayabrata Dhar ◽  
Francesco Danza ◽  
Arkajyoti Ghoshal ◽  
Sarah Elisabeth Mueller ◽  
...  
Keyword(s):  
Lipid Droplets ◽  
Red Tide ◽  
Mechanical Energy ◽  
Optimal Growth ◽  
Active Role ◽  
Phosphorus Limitation ◽  
Vertical Movement ◽  
Nitrogen And Phosphorus ◽  
And Migration ◽  
Motile Species

As open oceans continue to warm, modified currents and enhanced stratification exacerbate nitrogen and phosphorus limitation, constraining primary production. The ability to migrate vertically bestows motile phytoplankton a crucial – albeit energetically expensive – advantage toward vertically redistributing for optimal growth, uptake and resource storage in nutrient-limited water columns. However, this traditional view discounts the possibility that phytoplankton migration may be actively selected by the storage dynamics when nutrients turn limiting. Here we report that storage and migration in phytoplankton are coupled traits, whereby motile species harness energy storing lipid droplets (LDs) to biomechanically regulate migration in nutrient limited settings. LDs grow and translocate directionally within the cytoplasm to accumulate below the cell nucleus, tuning the speed, trajectory and stability of swimming cells. Nutrient reincorporation reverses the LD translocation, restoring the homeostatic migratory traits measured in population-scale millifluidic experiments. Combining intracellular LD tracking and quantitative morphological analysis of red-tide forming alga, Heterosigma akashiwo , along with a model of cell mechanics, we discover that the size and spatial localization of growing LDs govern the ballisticity and orientational stability of migration. The strain-specific shifts in migration which we identify here are amenable to a selective emergence of mixotrophy in nutrient-limited phytoplankton. We rationalize these distinct behavioral acclimatization in an ecological context, relying on concomitant tracking of the photophysiology and reactive oxygen species (ROS) levels, and propose a dissipative mechanical energy budget for motile phytoplankton for alleviating nutrient limitation. The emergent resource acquisition strategies, enabled by distinct strain-specific migratory acclimatizing mechanisms, highlight the active role of the reconfigurable cytoplasmic LDs in vertical movement. By uncovering a mechanistic coupling between dynamics of intracellular changes to physiologically governed migration strategies, this work offers a tractable framework to delineate diverse strategies which phytoplankton may harness to maximize fitness and resource pool in nutrient-limited open oceans of the future.

scholarly journals Atlantic salmon require long-chain n-3 fatty acids for optimal growth throughout the seawater period

2016 ◽  
Vol 5 ◽  
Author(s):  
Grethe Rosenlund ◽  
Bente E. Torstensen ◽  
Ingunn Stubhaug ◽  
Nafiha Usman ◽  
Nini H. Sissener
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Atlantic Salmon ◽  
Fold Increase ◽  
Optimal Growth ◽  
Dietary Fatty Acids ◽  
Nutritional Requirement ◽  
Retention Efficiency ◽  
Long Chain

AbstractThe nutritional requirement for n-3 long-chain PUFA in fast-growing Atlantic salmon (Salmo salar) during grow out in the sea is not well documented. Diets were formulated with levels of EPA (20 : 5n-3) and DHA (22 : 6n-3) ranging from 1·3 to 7·4 % of fatty acids (4–24 g/kg feed). Two long-term trials were conducted through the seawater phase, the first at 6 and 12°C, and the second at 12°C. In the first trial, growth at both temperatures was significantly lower in fish fed 1·4 % EPA+DHA of total fatty acids compared with the 5·2 % EPA+DHA group. In the second trial, growth was significantly lower in fish fed 1·3 and 2·7 % compared with 4·4 and 7·4 % EPA + DHA. Fatty acid composition in the fish reflected diet composition, but only after a 7-fold increase in body weight did the fatty acid profile of the fish stabilise according to dietary fatty acids (shown for EPA and DHA). The retention efficiency of DHA increased with decreasing dietary levels, and was 120–190 and 120–200 % in trials 1 and 2, respectively. The retention efficiency of EPA was lower (60–200 %), and values >100 % were only achieved at the lowest dietary levels in both trials. Temperature did not affect fatty acid retention efficiency. These results suggest that Atlantic salmon have a specific requirement for EPA + DHA >2·7 % of fatty acids for optimal long-term growth in seawater, and that short-term growth trials with less weight increase would not show these effects.

scholarly journals Temperature effects on growth rates and fatty acid content in freshwater algae and cyanobacteria

2018 ◽  
Vol 35 ◽  
pp. 500-507 ◽  
Author(s):  
Jakob O. Nalley ◽  
Daniel R. O'Donnell ◽  
Elena Litchman
Keyword(s):  
Fatty Acid ◽  
Growth Rates ◽  
Acid Content ◽  
Temperature Effects ◽  
Fatty Acid Content ◽  
Freshwater Algae

Dietary effect on bovine milk fat conjugated linoleic acid content

2000 ◽  
Vol 25 ◽  
pp. 283-293
Author(s):  
F. Lawless ◽  
J.J. Murphy ◽  
S. Fitzgerald ◽  
B. O’Brien ◽  
R. Devery ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Growth Rates ◽  
Milk Fat ◽  
Methyl Esters ◽  
Bovine Milk ◽  
Fold Increase ◽  
Linoleic Acid Content ◽  
Grass Growth

AbstractConjugated linoleic acid (cis-9, trans-11-C18:2; CLA) in milk arises as a result of microbial biohydrogenation of dietary linoleic and linolenic acids in the rumen (Kepler and Tove, 1967). Milk fat CLA concentrations were significantly (P<0.05) higher when cows were fed silage supplemented with pulp’n brew (a mixture of brewers grains, a by-product of the brewing industry, and sugar beet pulp in dry matter proportions of 0.65:0.35), compared with silage alone (Trial 1). Intake of spring grass resulted in a 2.1–fold increase in milk fat CLA concentrations over cows receiving autumn grass. Throughout lactation in Trial 2, spring calving cows produced higher milk fat CLA concentrations (from 0.5-2.7 g/100 g fatty acid methyl esters (FAME)) than autumn calving cows (0.3-1.7 g/100 g FAME); the former having spent 80% and the latter 50% of lactation on pasture. The CLA content was higher in late lactation milk compared with early lactation milk in both herds. There were no significant differences in milk yields or milk constituent yields between the herds. Manufacturing milk obtained between March and September was analyzed for milk fatty acid composition and the data correlated with grass growth throughout the season. Significant positive correlations were obtained between grass growth rates and concentrations of CLA and linolenic acid in milk fat. The data indicate that seasonal variation in milk fat CLA concentrations may be attributed to variation in pasture growth rates.

scholarly journals Anaerovirgula multivorans gen. nov., sp. nov., a novel spore-forming, alkaliphilic anaerobe isolated from Owens Lake, California, USA

2006 ◽  
Vol 56 (11) ◽  
pp. 2623-2629 ◽  
Author(s):  
Elena V. Pikuta ◽  
Takashi Itoh ◽  
Paul Krader ◽  
Jane Tang ◽  
William B. Whitman ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Soda Lake ◽  
Optimal Growth ◽  
Major Fatty Acid ◽  
Rrna Gene ◽  
Phenotypic Properties ◽  
Owens Lake ◽  
Size Growth ◽  
Clostridial Cluster ◽  
Type Strains

A novel, alkaliphilic, obligately anaerobic bacterium, strain SCAT, was isolated from mud sediments of a soda lake in California, USA. The rod-shaped cells were motile, Gram-positive, formed spores and were 0.4–0.5×2.5–5.0 μm in size. Growth occurred within the pH range 6.7–10.0 and was optimal at pH 8.5. The temperature range for growth was 10–45 °C, with optimal growth at 35 °C. NaCl was required for growth. Growth occurred at 0.5–9.0 % (w/v) NaCl and was optimal at 1–2 % (w/v). The novel isolate was a catalase-negative chemo-organoheterotroph that fermented sugars, proteolysis products, some organic and amino acids, glycerol, d-cellobiose and cellulose. It was also capable of growth by the Stickland reaction. Strain SCAT was sensitive to tetracycline, chloramphenicol, rifampicin and gentamicin, but it was resistant to ampicillin and kanamycin. The G+C content of the genomic DNA was 34.2 mol%. Major fatty acid components were C14 : 0, iso-C15 : 0, C16 : 1 ω9c and C16 : 0. 16S rRNA gene sequence analysis of strain SCAT showed a similarity of approximately 97 % with the type strains of Clostridium formicaceticum and Clostridium aceticum in clostridial cluster XI and a similarity of less than 94.2 % to any other recognized Clostridium species and those of related genera in this cluster. Strain SCAT was clearly differentiated from C. formicaceticum and C. aceticum based on comparison of their phenotypic properties and fatty acid profiles, as well as low levels of DNA–DNA relatedness between strain SCAT and the type strains of these two species. Therefore, strain SCAT is considered to represent a novel species of a new genus, Anaerovirgula multivorans gen. nov., sp. nov., in clostridial cluster XI. The type strain is SCAT (=ATCC BAA-1084T=JCM 12857T=DSM 17722T=CIP 107910T).

Quantitative and Physiological Analyses of Chloride Dependence of Growth of Halobacillus halophilus

1998 ◽  
Vol 64 (10) ◽  
pp. 3813-3817 ◽  
Author(s):  
Markus Roeßler ◽  
Volker Müller
Keyword(s):  
Growth Rate ◽  
Quantitative Analysis ◽  
Growth Rates ◽  
Chloride Concentration ◽  
Optimal Growth ◽  
Uptake System ◽  
Chloride Uptake ◽  
Molecular Masses ◽  
Final Yield ◽  
Energy Dependent

ABSTRACT A quantitative analysis of the Cl− dependence of growth of Halobacillus halophilus was performed. Optimal growth rates were obtained at Cl− concentrations of between 0.5 and 2.0 M, and the final yield was also strictly dependent on the Cl− concentration. Br− but not I−, SO4 2−, NO2 −, SO2 −, OCN−, SCN−, BO2 −, or BrO3 − could substitute for Cl−. To analyze the function of chloride, chloride concentration was determined. At low external Cl− (Cle −) concentrations, the growth rate was low and Cl− was excluded from the cytoplasm; increasing the Cle −concentration led to an increase in the growth rate and an energy-dependent uptake of Cl−, thus decreasing the Cle −/internal Cli − gradient from ≥10 at 0.1 M Cle − to a nearly constant value of 2 at Cle − concentrations which allowed optimal growth. Two membrane proteins with apparent molecular masses of 31 and 16 kDa which were identified to be specific for Cl−-grown cultures are possible candidates for a chloride uptake system.

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