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

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.

Download Full-text

Inhibitory effects of Pontederia cordata on the growth of Microcystis aeruginosa

Water Science & Technology ◽

10.2166/wst.2018.090 ◽

2018 ◽

Vol 2017 (1) ◽

pp. 99-107 ◽

Cited By ~ 2

Author(s):

Yanping Qian ◽

Ning Xu ◽

Juan Liu ◽

Runan Tian

Keyword(s):

Microcystis Aeruginosa ◽

Inhibitory Effect ◽

Butyl Alcohol ◽

Inhibition Rate ◽

Inhibitory Effects ◽

Fibrous Root ◽

Pontederia Cordata ◽

Algal Inhibition ◽

Organic Extracts ◽

Acetone Extracts

Abstract This study investigated the effect of Pontederia cordata on Microcystis aeruginosa growth in three different experimental settings: (i) co-cultivation, (ii) exposure of cyanobacteria to culture water of P. cordata, and (iii) exposure of M. aeruginosa to organic extracts of P. cordata. Results showed that the growth of M. aeruginosa was significantly inhibited by co-cultivation, with the highest inhibition rate of 61.9% within 5 days. Moreover, 95% culture water with P. cordata could markedly inhibit the growth of M. aeruginosa, with inhibition rate of 98.3% on day 6, indicating that most of the algal cells died. The organic extracts of fibrous root showed stronger inhibition effect than the leaf and stalk extracts. Acetone extract of fibrous root showed the strongest inhibitory effect on M. aeruginosa. Different components of 80% acetone extracts from fibrous root exhibited varied effects on the growth of M. aeruginosa. Ethyl acetate and water components had strong inhibition effects on M. aeruginosa. By contrast, n-butyl alcohol components had weak inhibition effects, and hexane components even promoted the growth of M. aeruginosa. Allelochemicals of P. cordata were primarily released into the water through the fibrous root. Results indicated that P. cordata can be applied in environmentally friendly algal inhibition.

Download Full-text

Unsaturated fatty acids inhibit ADP- arachidonate-induced platelet aggregation without affecting thromboxane synthesis

Biochemistry and Cell Biology ◽

10.1139/o86-121 ◽

1986 ◽

Vol 64 (9) ◽

pp. 906-913 ◽

Cited By ~ 3

Author(s):

Ella Dratewka-Kos ◽

D. O. Tinker ◽

Brigitte Kindl

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Platelet Aggregation ◽

Unsaturated Fatty Acids ◽

Inhibitory Effect ◽

Inhibitory Effects ◽

Low Concentrations ◽

Fatty Acid Inhibition ◽

Induced Aggregation ◽

Protein Free Medium

The inhibitory effects of three cis-unsaturated C18 fatty acids (oleic, linoleic, and linolenic acids, sodium salts) on ADP- and sodium-arachidonate-induced aggregation of washed rabbit platelets were investigated. When the platelets were suspended in protein-free medium containing dextran, it was found that these fatty acids at very low concentrations (2–45 μM) were potent inhibitors of platelet responsiveness and the inhibitory effect occurred within seconds. The inhibition of ADP-induced aggregation was not affected by abolishing the activity of platelet cyclooxygenase using aspirin. Human serum albumin relieved the inhibition caused by fatty acids for both ADP- and arachidonate-induced aggregation. The inhibitory effect of fatty acids does not seem to be due to decreased thromboxane formation (except possibly in the case of linolenate), and the relief of fatty acid inhibition by albumin does not potentiate thromboxane B2 formation from exogenous arachidonate. It is suggested that the inhibitory effect of polyunsaturated fatty acids on platelet aggregation is specific and not related to a general surfactant effect, since inhibition occurs far below the critical micelle concentration of fatty acid soaps.

Download Full-text

Abundant Allelochemicals and the Inhibitory Mechanism of the Phenolic Acids in Water Dropwort for the Control of Microcystis aeruginosa Blooms

Plants ◽

10.3390/plants10122653 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2653

Author(s):

Jixiang Liu ◽

Yajun Chang ◽

Linhe Sun ◽

Fengfeng Du ◽

Jian Cui ◽

...

Keyword(s):

Microcystis Aeruginosa ◽

Phenolic Acids ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Inhibitory Effect ◽

Simultaneous Action ◽

Inhibitory Effects ◽

Chl A ◽

Ferulic Acids ◽

Water Dropwort

In recent years, with the frequent global occurrence of harmful algal blooms, the use of plant allelopathy to control algal blooms has attracted special and wide attention. This study validates the possibility of turning water dropwort into a biological resource to inhibit the growth of harmful Microcystis aeruginosa blooms via allelopathy. The results revealed that there were 33 types of allelopathic compounds in the water dropwort culture water, of which 15 were phenolic acids. Regarding water dropwort itself, 18 phenolic acids were discovered in all the organs of water dropwort via a targeted metabolomics analysis; they were found to be mainly synthesized in the leaves and then transported to the roots and then ultimately released into culture water where they inhibited M. aeruginosa growth. Next, three types of phenolic acids synthesized in water dropwort, i.e., benzoic, salicylic, and ferulic acids, were selected to clarify their inhibitory effects on the growth of M. aeruginosa and their mechanism(s) of action. It was found that the inhibitory effect of phenolic acids on the growth of M. aeruginosa increased with the increase of the exposure concentration, although the algae cells were more sensitive to benzoic acid than to salicylic and ferulic acids. Further study indicated that the inhibitory effects of the three phenolic acids on the growth of M. aeruginosa were largely due to the simultaneous action of reducing the number of cells, damaging the integrity of the cell membrane, inhibiting chlorophyll a (Chl-a) synthesis, decreasing the values of F0 and Fv/Fm, and increasing the activity of the antioxidant enzymes (SOD, POD, and CAT) of M. aeruginosa. Thus, the results of this study indicate that both culture water including the rich allelochemicals in water dropwort and biological algae inhibitors made from water dropwort could be used to control the growth of noxious algae in the future.

Download Full-text

Effects of thia-substituted fatty acids on mitochondrial and peroxisomal β-oxidation. Studies in vivo and in vitro

Biochemical Journal ◽

10.1042/bj2700167 ◽

1990 ◽

Vol 270 (1) ◽

pp. 167-173 ◽

Cited By ~ 31

Author(s):

R Hovik ◽

H Osmundsen ◽

R Berge ◽

A Aarsland ◽

S Bergseth ◽

...

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Competitive Inhibition ◽

Inhibitory Effect ◽

Inhibitory Effects ◽

Duration Of Treatment ◽

Acyl Coa Oxidase ◽

Dose Dependent

1. The effects of 3-, 4- and 5-thia-substituted fatty acids on mitochondrial and peroxisomal β-oxidation have been investigated. When the sulphur atom is in the 4-position, the resulting thia-substituted fatty acid becomes a powerful inhibitor of β-oxidation. 2. This inhibition cannot be explained in terms of simple competitive inhibition, a phenomenon which characterizes the inhibitory effects of 3- and 5-thia-substituted fatty acids. The inhibitory sites for 4-thia-substituted fatty acids are most likely to be the acyl-CoA dehydrogenase in mitochondria and the acyl-CoA oxidase in peroxisomes. 3. The inhibitory effect of 4-thia-substituted fatty acids is expressed both in vitro and in vivo. The effect in vitro is instantaneous, with up to 95% inhibition of palmitoylcarnitine oxidation. The effect in vivo, in contrast, is dose-dependent and increases with duration of treatment. 4. Pretreatment of rats with a 3-thia-substituted fatty acid rendered mitochondrial β-oxidation less sensitive to inhibition by 4-thia-substituted fatty acids.

Download Full-text

Effect of fatty acids on endothelium-dependent relaxation in the rabbit aorta

Clinical Science ◽

10.1042/cs20060001 ◽

2006 ◽

Vol 111 (2) ◽

pp. 145-151 ◽

Cited By ~ 25

Author(s):

Indika Edirisinghe ◽

Kellie McCormick Hallam ◽

C. Tissa Kappagoda

Keyword(s):

Nitric Oxide ◽

Fatty Acids ◽

Stearic Acid ◽

Time Course ◽

Plasma Concentrations ◽

Rabbit Aorta ◽

Inhibitory Effect ◽

Inhibitory Effects ◽

The Metabolic Syndrome ◽

Endothelium Dependent Relaxation

The metabolic syndrome, Type II (non-insulin-dependent) diabetes and obesity are associated with endothelial dysfunction and increased plasma concentrations of NEFAs (non-esterified fatty acids; free fatty acids). The present study was undertaken to define the inhibitory effects of saturated NEFAs on EDR (endothelium-dependent relaxation). Experiments were performed in rings of rabbit aorta to establish (i) dose–response relationships, (ii) the effect of chain length, (iii) the effect of the presence of double bonds, (iv) reversibility and time course of inhibition, and (v) the effect on nitric oxide production. Aortic rings were incubated (1 h) with NEFA–albumin complexes derived from lauric (C12:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0) and linolenic (C18:3) acids. EDR induced by acetylcholine (0.1–10 μmol/l) was measured after pre-contraction with noradrenaline. Inhibition of EDR was dose-dependent (0.5–2 mmol/l NEFA), and the greatest inhibition (51%) was observed with stearic acid (2 mmol/l). Lauric acid had the smallest inhibitory effect. The inhibitory effects were always reversible and were evident after 15 min of incubation. Linolenic acid caused a significantly lower inhibition of EDR than stearic acid. SOD (superoxide dismutase) restored the inhibitory effect caused by NEFAs, suggesting the involvement of ROS (reactive oxygen species) in removing nitric oxide. The nitric oxide concentration measured after exposure of the rings to acetylcholine was lower after incubation with NEFAs than with Krebs buffer alone. This finding is consistent with removal of nitric oxide by ROS. This claim was supported by the demonstration of increased concentrations of nitrated tyrosine in the rings incubated with NEFAs.

Download Full-text

Inhibitory Effects of Cu2O/SiO2 on the Growth of Microcystis aeruginosa and Its Mechanism

Nanomaterials ◽

10.3390/nano9121669 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1669 ◽

Cited By ~ 3

Author(s):

Gongduan Fan ◽

Minchen Bao ◽

Bo Wang ◽

Shimin Wu ◽

Lingxi Luo ◽

...

Keyword(s):

Oxidative Damage ◽

Chlorophyll A ◽

Microcystis Aeruginosa ◽

Inhibitory Effect ◽

Total Soluble Protein ◽

Inhibition Mechanism ◽

Inhibition Rate ◽

Inhibitory Effects ◽

Cyanobacteria Blooms ◽

Relative Inhibition

In this study, a novel nanomaterial Cu2O/SiO2 was synthesized based on nano-SiO2, and the inhibitory effects of different concentrations of Cu2O/SiO2 on the growth of Microcystis aeruginosa (M. aeruginosa) were studied. At the same time, the mechanism of Cu2O/SiO2 inhibiting the growth of M. aeruginosa was discussed from the aspects of Cu2+ release, chlorophyll a destruction, oxidative damage, total protein, and the phycobiliprotein of algae cells. The results showed that low doses of Cu2O/SiO2 could promote the growth of M. aeruginosa. When the concentration of Cu2O/SiO2 reached 10 mg/L, it exhibited the best inhibitory effect on M. aeruginosa, and the relative inhibition rate reached 294% at 120 h. In terms of the algae inhibition mechanism, Cu2O/SiO2 will release Cu2+ in the solution and induce metal toxicity to algae cells. At the same time, M. aeruginosa might suffer oxidative damage by the free radicals, such as hydroxyl radicals released from Cu2O/SiO2, affecting the physiological characteristics of algae cells. Moreover, after the addition of Cu2O/SiO2, a decrease in the content of chlorophyll a, total soluble protein, and phycobiliprotein was found, which eventually led to the death of M. aeruginosa. Therefore, Cu2O/SiO2 can be used as an algaecide inhibitor for controlling harmful cyanobacteria blooms.

Download Full-text

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646570 ◽

1989 ◽

Vol 61 (02) ◽

pp. 254-258 ◽

Cited By ~ 21

Author(s):

Margaret L Rand ◽

Peter L Gross ◽

Donna M Jakowec ◽

Marian A Packham ◽

J Fraser Mustard

Keyword(s):

Cyclic Amp ◽

Inhibitory Effect ◽

Rabbit Platelet ◽

Inhibitory Effects ◽

Low Concentrations ◽

Rabbit Platelets ◽

High Concentrations ◽

In Vitro Effects ◽

Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Download Full-text

Inhibition of ADP-Induced Responses in Human Platelets by Agents Elevating the Cyclic AMP Level: Comparison of Aggregation and Shape Change

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661208 ◽

1984 ◽

Vol 52 (03) ◽

pp. 333-335 ◽

Cited By ~ 4

Author(s):

Vider M Steen ◽

Holm Holmsen

Keyword(s):

Inhibitory Action ◽

Human Platelet ◽

Platelet Rich Plasma ◽

Shape Change ◽

Inhibitory Effect ◽

Human Platelets ◽

Inhibitory Effects ◽

Early Step ◽

Stimulus Response ◽

Sequential Relationship

SummaryThe inhibitory effect of cAMP-elevating agents on shape change and aggregation in human platelets was studied to improve the understanding of the sequential relationship between these two responses.Human platelet-rich plasma was preincubated for 2 min at 37° C with prostaglandin E1 or adenosine, agents known to elevate the intracellular level of cAMP. Their inhibitory effects on ADP-induced shape change and aggregation were determined both separately and simultaneously. The dose-inhibition patterns for shape change and aggregation were similar for both PGE1 and adenosine. There was no distinct difference between the inhibitory action of these two inhibitors.These observations suggest that elevation of the intracellular concentration of cAMP interferes with an early step in the stimulus-response coupling that is common for aggregation and shape change.

Download Full-text

The Inhibitory Effect of Heparin and Related Glycosaminoglycans on Neutrophil Chemotaxis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661157 ◽

1984 ◽

Vol 52 (02) ◽

pp. 134-137 ◽

Cited By ~ 69

Author(s):

Yaacov Matzner ◽

Gerard Marx ◽

Ruth Drexler ◽

Amiram Eldor

Keyword(s):

Specific Binding ◽

Anticoagulant Activity ◽

Neutrophil Migration ◽

Inhibitory Effect ◽

Chemotactic Factor ◽

Human Neutrophils ◽

Boyden Chamber ◽

Neutrophil Chemotaxis ◽

Inhibitory Effects ◽

Chemotactic Factors

SummaryClinical observations have shown that heparin has antiinflammatory activities. The effect of heparin on neutrophil chemotaxis was evaluated in vitro in the Boyden Chamber. This method enabled differentiation between the direct effects of heparin on neutrophil migration and locomotion, and its effects on chemotactic factors. Heparin inhibited both the random migration and directed locomotion of human neutrophils toward zymosan-activated serum (ZAS) and F-met-leu-phe (FMLP). Inhibition was found to be dependent on the concentrations of the heparin and of the chemotactic factors. No specific binding of heparin to the neutrophils could be demonstrated, and heparin’s inhibitory effects were eliminated by simple washing of the cells. When added directly to the chamber containing chemotactic factor, heparin inhibited the chemotactic activity of ZAS but not that of FMLP, suggesting a direct inhibitory effect against C5a, the principal chemotactic factor in ZAS.Experiments performed with low-molecular-weight heparin, N-desulfated heparin, dextran sulfate, chondroitin sulfate and dextran indicated that the inhibitory effects of heparin on neutrophil chemotaxis are not related to its anticoagulant activity, but probably depend on the degree of sulfation of the heparin molecule.

Download Full-text