Structures and activities of tiahuramides A–C, cyclic depsipeptides from a tahitian collection of the marine cyanobacterium Lyngbya majuscula

The structures of three new cyclic depsipeptides, tiahuramides A (1), B (2), and C (3), from a French Polynesian collection of the marine cyanobacterium Lyngbya majuscula are described. The planar structures of these compounds were established by a combination of mass spectrometry and 1D and 2D NMR experiments. Absolute configurations of natural and nonproteinogenic amino acids were determined through a combination of acid hydrolysis, derivitization with Marfey’s reagent, and HPLC. The absolute configuration of hydroxy acids was confirmed by Mosher’s method. The antibacterial activities of tiahuramides against three marine bacteria were evaluated. Compound 3 was the most active compound of the series, with an MIC of 6.7 μM on one of the three tested bacteria. The three peptides inhibit the first cell division of sea urchin fertilized eggs with IC50 values in the range from 3.9 to 11 μM. Tiahuramide B (2), the most potent compound, causes cellular alteration characteristics of apoptotic cells, blebbing, DNA condensation, and fragmentation, already at the first egg cleavage. The cytotoxic activity of compounds 1–3 was tested in SH-SY5Y human neuroblastoma cells. Compounds 2 and 3 showed an IC50 of 14 and 6.0 μM, respectively, whereas compound 1 displayed no toxicity in this cell line at 100 μM. To determine the type of cell death induced by tiahuramide C (3), SH-SY5Y cells were costained with annexin V–FITC and propidium iodide and analyzed by flow cytometry. The double staining indicated that the cytotoxicity of compound 3 in this cell line is produced by necrosis

Metabolic engineering of marine microbes: the potential of Lyngbya Majuscula as a natural products cell factory

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Coenzyme Q10 production from marine bacteria

Disclosed are methods, compounds and compositions related to the production of coenzyme

Critical assessment of various techniques for the extraction of carotenoids and co-enzyme Q10 from the Thraustochytrid strain ONC-T18

A variety of techniques for extracting carotenoids from the marine Thraustochytrium sp. ONC-T18 was compared. Specifically, the organic solvents acetone, ethyl acetate, and petroleum ether were tested, along with direct and indirect ultrasonic assisted extraction (probe vs bath) methods. Techniques that used petroleum ether/acetone/water (15:75:10, v/v/v) with 3 h of agitation, or 5 min in an ultrasonic bath, produced the highest extraction yields of total carotenoids (29&minus;30.5 &mu;g g-1). Concentrations up to 11.5 &mu;g g-1 of canthaxanthin and 17.5 &mu;g g-1 of &beta;-carotene were detected in extracts stored for 6 weeks. Astaxanthin and echinenone were also detected as minor compounds. Extracts with and without antioxidants showed similar carotenoid concentration profiles. However, total carotenoid concentrations were approximately 8% higher when antioxidants were used. Finally, an easy-to-perform and inexpensive method to detect co-enzymes in ONC-T18 was also developed using silica gel TLC plates. Five percent methanol in toluene as a mobile phase consistently eluted co-enzyme Q10 standards and could separate the co-enzyme fractions present in ONC-T18. <br /

Eukaryotic microorganisms for producing lipids and antioxidants

Disclosed are compositions and methods related to eukaryotic microorganisms that can produce unsaturated fatty acids which can be purified and used

Transesterification of fish oil to produce fatty acid ethyl esters using ultrasonic energy

This study evaluated the production of fatty acid ethyl esters from fish oil using ultrasonic energy and alkaline catalysts dissolved in ethanol. The feasibility of fatty acid ethyl ester production was determined using an ultrasonic bath and probe, and between 0.5 and 1% KOH (added to the fish oil). Furthermore, factors such as ultrasonic device (bath and probe), catalyst (KOH and C2H5ONa), temperature (20 and 60 &deg;C), and duration of exposure (10&ndash;90 min) were assessed. Sodium ethoxide was found to be a more efficient catalyst than KOH when transesterifying fish oil. Ultrasonic energy applied for greater than 30 min at 60 &deg;C using 0.8% of C2H5ONa as a catalyst transesterified over 98% fish oil triglycerides to fatty acid ethyl esters. It is reasonable to conclude that the yield of fatty acid ethyl esters produced by applying ultrasonic energy to fish oil is related to the sonication time. Due to increases in the surface area contact between the reactants and the catalyst, ultrasonic energy has the potential to reduce the production time required by a conventional large-scale commercial transesterification method that uses agitation as a way of mixing.<br /

Optimization of fatty acid determination in selected fish and microalgal oils

The use of ten fatty acid methyl ester reference standards coupled with a detailed quantification method was shown to significantly optimize the fatty acid determination of selected fish and microalgal oils when compared to methods that use only one reference standard (C19:0 or C23:0) as a relative response factor. When using the mixture of ten reference standards after transesterifying oils with NaOH/BF3, determination of total fatty acids, eicosapentaenoic acid and docosahexaenoic acid improved by an average of 7.3, 11.5 and 8.4%, respectively. Furthermore, improvements of 13.9, 18.9 and 6.8% of total fatty acids, EPA and DHA, respectively, were obtained when using the mixture of reference standards for fatty acid determination after directly extracting and transesterifying oil contained in microalgal cells with a mixture of methanol, HCl and chloroform. Fatty acid methyl ester standards dissolved in isooctane showed &lt;5% variability throughout 130 days of stability testing when stored at &minus;20 &deg;C. The optimized method can be used for improving the quantification of fatty acids in both oils (fish and microalgal oils) and dry microalgal cells.<br /

Unraveling the inhibitory effects of acetate on ethanol production in CEN.PK

In this study, we used the ORACLE (Optimization and Risk Analysis of Complex Living Entities)[1] framework to study the impact of extracellular acetic acid on the S. cerevisiae metabolism with the aim to improve ethanol production in the presence of this inhibitor found in significant concentrations in lignocellulosic hydrolysates. First, we derived a consistently reduced core model (279 metabolites and 382 reactions) of S. cerevisiae from the iMM904 genome scale reconstruction. We integrated thermodynamic and experimentally measured information about the metabolite concentrations and reaction fluxes, to identify thermodynamically feasible operational configurations of the network under different experimental conditions using the novel Flux Directionality Profile Analysis (FDPA) technique[2,3]. We then computed a population of stoichiometrically, thermodynamically, kinetically and physiologically consistent log-linear kinetics models. These models were used to (i) explore the flexibility and robustness of the operational states; (ii) identify the differences of the flux profiles for different doses of acetate during ethanol production; and (iii) derive optimal strategies for improvement of the ethanol production under these physiological conditions