Differential sensitivity of fatty acids and lipid damage in Microcystis aeruginosa (cyanobacteria) exposed to increased temperature

Two experiments were conducted to study the effects of processing techniques on in vitro ruminal undegradable protein (RUP), in vitro ruminal biohydrogenation of fatty acids, and in vitro dry matter digestibility (IVDMD) of rolled flaxseed. In the first experiment, the influence of micronization treatment (130°C for 4 h, 140°C for 2 h, 150°C for 1 h, and 160°C for 0.5 h) was examined. The IVDMD significantly decreased when heating at 150°C for 1 h and 160°C for 0.5 h. Degradation rate of crude protein (CP) decreased and RUP concentration increased in parallel with heating temperature. Micronization had little effect on biohydrogenation of fatty acids. In the second experiment, the influence of sugar addition [none, soaked in a high fructose corn syrup (HFCS) or a lignosulfonate solution] before heating, either in an autoclave or a forced-air oven, at two temperatures (100 or 120°C), and two temperature holding times (30 and 60 min) was examined. Increased temperature and heating time decreased degradation rate of CP and increased the RUP fraction of flaxseeds. There was a decre ase in IVDMD with increased temperature when fructose was added. Moist heating is a better option than dry heating, but it has little advantage over not heating to prevent ruminal biohydrogenation of polyunsaturated fatty acids of flaxseeds. Key words: Biohydrogenation, degradability, in vitro, micronization, lignosulfonate

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Fatty acids from the cyanobacterium Microcystis aeruginosa with potent inhibitory effects on fish gill Na+/K+-ATPase activity.

Journal of Experimental Biology ◽

10.1242/jeb.201.1.81 ◽

1998 ◽

Vol 201 (1) ◽

pp. 81-89

Author(s):

N R Bury ◽

G A Codd ◽

S E Wendelaaar Bonga ◽

G Flik

Keyword(s):

Fatty Acids ◽

Microcystis Aeruginosa ◽

Basolateral Membrane ◽

Tight Binding ◽

Oreochromis Mossambicus ◽

Inhibitory Effect ◽

Cyanobacterial Blooms ◽

Inhibitory Effects ◽

Fish Kills ◽

Layer Chromatography

Fatty acids from two strains of the cyanobacterium Microcystis aeruginosa, PCC 7820 (a strain that produces the hepatotoxin microcystin-LR, MC-LR) and CYA 43 (a strain that produces only small quantities of MC-LR), were extracted, partially characterised and tested for their inhibitory effect on the K+-dependent p-nitrophenol phosphatase (pNPPase) activity of tilapia (Oreochromis mossambicus) gill basolateral membrane. Thin-layer chromatography of the lipids from dichloromethane:methanol extracts of M. aeruginosa PCC 7820 and CYA 43, using diethylether:isopropanol:formic acid (100:4.5:2.5) as solvent, yielded five inhibitory products from M. aeruginosa 7820 and six from M. aeruginosa CYA 43. None of these products could be related to MC-LR. The inhibitory behaviour of the products mimics that of a slow, tight-binding inhibitor. The inhibitory activity is removed by incubation of extracts with fatty-acid-free bovine serum albumin (FAF-BSA). However, FAF-BSA only partially reversed the inhibition of K+-dependent pNPPase on fish gills pre-exposed to the extracted products. We conclude that M. aeruginosa strains PCC 7820 and CYA 43 produce fatty acids with potent inhibitory effects on K+-dependent pNPPase. The release of these products following lysis of cyanobacterial blooms may help to explain fish kills through a disturbance of gill functioning.

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Simultaneous shifts in elemental stoichiometry and fatty acids of <i>Emiliania huxleyi</i> in response to environmental changes

Biogeosciences ◽

10.5194/bg-15-1029-2018 ◽

2018 ◽

Vol 15 (4) ◽

pp. 1029-1045 ◽

Cited By ~ 8

Author(s):

Rong Bi ◽

Stefanie M. H. Ismar ◽

Ulrich Sommer ◽

Meixun Zhao

Keyword(s):

Fatty Acids ◽

Environmental Changes ◽

Nutrient Deficiency ◽

Emiliania Huxleyi ◽

Differential Sensitivity ◽

Global Ocean ◽

High Pco2 ◽

Ecological Functions ◽

Elemental Stoichiometry ◽

P Supply

Abstract. Climate-driven changes in environmental conditions have significant and complex effects on marine ecosystems. Variability in phytoplankton elements and biochemicals can be important for global ocean biogeochemistry and ecological functions, while there is currently limited understanding on how elements and biochemicals respond to the changing environments in key coccolithophore species such as Emiliania huxleyi. We investigated responses of elemental stoichiometry and fatty acids (FAs) in a strain of E. huxleyi under three temperatures (12, 18 and 24 ∘C), three N : P supply ratios (molar ratios 10:1, 24:1 and 63:1) and two pCO2 levels (560 and 2400 µatm). Overall, C : N : P stoichiometry showed the most pronounced response to N : P supply ratios, with high ratios of particulate organic carbon vs. particulate organic nitrogen (POC : PON) and low ratios of PON vs. particulate organic phosphorus (PON : POP) in low-N media, and high POC : POP and PON : POP in low-P media. The ratio of particulate inorganic carbon vs. POC (PIC : POC) and polyunsaturated fatty acid proportions strongly responded to temperature and pCO2, both being lower under high pCO2 and higher with warming. We observed synergistic interactions between warming and nutrient deficiency (and high pCO2) on elemental cellular contents and docosahexaenoic acid (DHA) proportion in most cases, indicating the enhanced effect of warming under nutrient deficiency (and high pCO2). Our results suggest differential sensitivity of elements and FAs to the changes in temperature, nutrient availability and pCO2 in E. huxleyi, which is to some extent unique compared to non-calcifying algal classes. Thus, simultaneous changes of elements and FAs should be considered when predicting future roles of E. huxleyi in the biotic-mediated connection between biogeochemical cycles, ecological functions and climate change.

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Effects of high irradiance and iron concentration on pigment and fatty acid composition in the cyanobacterium Microcystis aeruginosa

Marine and Freshwater Research ◽

10.1071/mf98025 ◽

1998 ◽

Vol 49 (5) ◽

pp. 399 ◽

Cited By ~ 1

Author(s):

Kathryn Walsh ◽

Gary J. Jones ◽

R. Hugh Dunstan

Keyword(s):

Fatty Acids ◽

Microcystis Aeruginosa ◽

Iron Concentration ◽

Monounsaturated Fatty Acids ◽

High Irradiance ◽

High Iron ◽

Inland Lakes ◽

Artificial Illumination ◽

Almost All ◽

Iron Concentrations

Microcystis aeruginosa Kuetzing emend. was exposed to sunlight and artificial illumination at low (1 µM) and high (31 µM) iron concentrations over a 9 h period. With sunlight and low iron, cellular carotenoid and chlorophyll a concentrations decreased linearly with time, and membrane polyunsaturated fatty acids were reduced after 9 h. With sunlight and high iron, there was near-complete loss of all pigments and reduced concentrations of all major fatty acids within 3 h, presumably due to photooxidation; almost all phytol, poly- and monounsaturated fatty acids were absent after 9 h exposure in the high iron medium, indicating total destruction of membranes by iron-enhanced photooxidation. Although caution is required in extrapolating results from laboratory grown cultures to field populations, it is conceivable that high irradiance can influence the composition of cyanobacterial membranes during natural surface blooms. The subsequent survival and regeneration of cyanobacterial cells may be affected under the high iron concentrations which can occur in Australian inland lakes and rivers.

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Implication of total replacement of fish oil with vegetable oils on nutritional and lipid profiles of fish

Indonesian Journal of Tropical Aquatic ◽

10.22219/ijota.v4i1.12378 ◽

2021 ◽

Vol 4 (1) ◽

pp. 14-23

Author(s):

Christian Larbi Ayisi

Keyword(s):

Fatty Acids ◽

Nutritional Status ◽

Fish Oil ◽

Vegetable Oils ◽

Saturated Fatty Acids ◽

Marine Species ◽

Nutritional Composition ◽

Atherogenic Index ◽

Freshwater Species ◽

Lipid Damage

In this study, the effects of using vegetable oils solely in finfish feed on nutritional status as well as lipid damage were evaluated. Polyene index (PI), atherogenic index (AI) as well as hypocholesterolemic and hypercholesterolemic fatty acids were assessed. Also, n-3/n-6 and n-6/n-3 ratios were assessed. In all, 32 articles were used for this study after carefully assessing them. Eighteen (18) articles had studied Freshwater species (FWF) whiles fourteen (14) had studied Marine species (MF). TI, n-3/n-6, and n-6/n-3 were significantly higher in fish-fed saturated fatty acids (SFA), n-3, and n-6 dominant vegetables. We document that using vegetable oils without supplementing fish diets with fish oil does not compromise the nutritional status as well as lipid damage. This work provides important information about the effect of using 100% vegetable oils in fish with respect to the nutritional composition of the final product.

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Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095017 ◽

1972 ◽

Vol 30 ◽

pp. 350-351

Author(s):

K. Shankar Narayan ◽

Kailash C. Gupta ◽

Tohru Okigaki

Keyword(s):

Ultraviolet Light ◽

Mammalian Cells ◽

Biological Effects ◽

Survival Rates ◽

Chinese Hamster ◽

Cell Types ◽

Differential Sensitivity ◽

Ultrastructural Changes ◽

Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

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