The fatty acid composition of a Vibrio alginolyticus associated with the alga Cladophora coelothrix. Identification of the novel 9-methyl-10-hexadecenoic acid

Dissipative Photochemical Abiogenesis of the Purines

We have proposed that the abiogenesis of life around the beginning of the Archean may have been an example of "spontaneous" microscopic dissipative structuring of UV-C pigments under the prevailing surface ultraviolet solar spectrum. The thermodynamic function of these Archean pigments (the "fundamental molecules of life"), as for the visible pigments of today, was to dissipate the incident solar light into heat. We have previously described the non-equilibrium thermodynamics and the photochemical mechanisms which may have been involved in the dissipative structuring of the purines adenine and hypoxanthine from the common precursor molecules of hydrogen cyanide and water under this UV light. In this article, we extend our analysis to include the production of the other two important purines, guanine and xanthine. The photochemical reactions are presumed to occur within a fatty acid vesicle floating on a hot (∼80 ∘C) neutral pH ocean surface exposed to the prevailing UV-C light. Reaction-diffusion equations are resolved under different environmental conditions. Significant amounts of adenine (∼10-5 M) and guanine (∼10-6 M) are obtained within 60 Archean days, starting from realistic concentrations of the precursors hydrogen cyanide and cyanogen (∼10-5 M).

Cytotoxic and anti-excitotoxic effects of selected plant and algal extracts using COMET and cell viability assays

Excess glutamate in the central nervous system may be a major cause of neurodegenerative diseases with gradual loss and dysfunction of neurons. Primary or secondary metabolites from medicinal plants and algae show potential for treatment of glutamate-induced excitotoxicity. Three plant extracts were evaluated for impact on glutamate excitotoxicity-induced in primary cultures of retinal ganglion cells (RGC). These cells were treated separately in seven groups: control; Plicosepalus. curviflorus treated; Saussurea lappa treated; Cladophora glomerate treated. Cells were treated independently with 5, 10, 50, or 100 µg/ml of extracts of plant or alga material, respectively, for 2 h. Glutamate-treated cells (48 h with 5, 10, 50, or 100 µM glutamate); and P. curviflorus/glutamate; S. lappa/glutamate; C. glomerata/glutamate [pretreatment with extract for 2 h (50 and 100 µg/ml) before glutamate treatment with 100 µM for 48 h]. Comet and MTT assays were used to assess cell damage and cell viability. The number of viable cells fell significantly after glutamate exposure. Exposure to plant extracts caused no notable effect of viability. All tested plants extracts showed a protective effect against glutamate excitotoxicity-induced RGC death. Use of these extracts for neurological conditions related to excitotoxicity and oxidative stress might prove beneficial.

PTP1B-Inhibiting Branched-Chain Fatty Acid Dimers from Eremophila oppositifolia subsp. angustifolia Identified by High-Resolution PTP1B Inhibition Profiling and HPLC-PDA-HRMS-SPE-NMR Analysis

Ten new branched-chain fatty acid (BCFA) dimers with a substituted cyclohexene structure, five new monomers, and two known monomers, (2E,4Z,6E)-5-(acetoxymethyl)tetradeca-2,4,6-trienoic acid and its 5-hydroxymethyl analogue, were identified in the leaf extract of Eremophila oppositifolia subsp. angustifolia using a combination of HPLC-PDA-HRMS-SPE-NMR analysis and semipreparative-scale HPLC. The dimers could be classified as three types of Diels-Alder reaction products formed between monomers at two different sites of unsaturation of the dienophile. Two of the monomers represent potential biosynthetic intermediates of branched-chain fatty acids. Several compounds were found by high-resolution bioactivity profiling to inhibit PTP1B and were purified subsequently by semipreparative-scale HPLC. The dimers were generally more potent than the monomers with IC₅₀ values ranging from 2 to 66 μM, compared to 38-484 μM for the monomers. The ten fatty acid dimers represent both a novel class of compounds and a novel class of PTP1B inhibitors.

Cladophora glomerata methanolic extract decreases oxidative stress and improves viability and mitochondrial potential in equine adipose derived mesenchymal stem cells (ASCs)

Reactive oxygen species (ROS) are key mediators of several cellular damage and thus associated with equine diseases such as inflammation and metabolic syndrome. This study aimed to evaluate the protective and antioxidant activities of methanolic extract prepared from Cladophora glomerata (C. glomerata) biomass, on equine adipose derived mesenchymal stem cells (EqASCs), under experimental oxidative stress induced by H₂O₂. Pre-treatment of EqASCs cells with different concentrations of C. glomerata methanolic extract (1% and 5%) provided a clear protection against cellular damage triggered by H₂O₂. The cell's apoptotic status was significantly regulated, with promotion of cell viability, down-regulation of pro-apoptotic (p21, p53, Bax and Casp-9) genes expression, concomitant to up-regulation of the survival gene Bcl-2, this being supported by a mitigation of the endoplasmic reticulum (ER) stress and significant minimization of mitochondrial dysfunction. The results also showed that C. glomerata extract significantly increased the antioxidant enzymes Superoxide dismutase (SOD) and Catalase (CAT) activities, positively regulated the enzymes genes expression, and markedly reduced the protein carbonyls derivatives production. Finally, RT-qPCR analysis of the inflammatory related genes allowed to highlight a promising anti-inflammatory and immunomodulatory effect of this extract. Due to the valuable antioxidant and anti-inflammatory activities, C. glomerata may have potential benefits for the prevention of equine diseases associated with oxidative stress, including metabolic syndrome.

Lanesoic Acid: A Cytotoxic Zwitterion from Theonella sp

Lanesoic acid (1) was isolated and characterized from Theonella sp. during PharmaMar's ongoing program to study cytotoxic substances from marine sources. Its planar structure, elucidated by spectral analysis (NMR, IR, UV, and MS), possesses an unusual skeleton containing a tetrahydropyrimidine cation that is stabilized as a zwitterion by an internal carboxylate counterion. The stereostructure of 1 was deduced from ROESY-NOESY, J-based configurational analysis (JBCA), and density functional theory (DFT) computational calculations fitted using the recently published DP4+ parameter. Compound 1 was moderately active and selective against pancreas PSN1 cells (IC₅₀ = 8.9 μg/mL) and inactive against colon HT-29, breast MD-MB-23, and NSCLC lung tumor cells.

Biomass of freshwater Cladophora as a raw material for agriculture and the cosmetic industry

This study was undertaken to determine mineral content, amino acid and fatty acid composition of the freshwater macroalga – Cladophora glomerata. The studies were based on the content comparison in algal biomass collected from a lake and cultured in a laboratory. To determine the ability of copper cumulating by macroalgae, Cladophora was cultured in the medium supplemented with Cu ions. This study indicated that the relative abundance of metals in filaments decreased in the following order: Ca > K > Mg > Na > Fe > Cu > Zn > Pb > As > Ni > Cd > Mn > Cr > Co. Total protein content ranged from 14.45% in Cladophora from a lake to 26.55% in Cladophora from a laboratory. The main amino acids analyzed were aspartic and glutamic acid. The fatty acid content in the dry matter of the extract varied depending on the extraction method used: ethylene alcohol (19.0%), acetone (34.5%) or supercritical fluid extraction (62.5%). Freshwater C. glomerata due to the macrominerals, trace elements, amino and fatty acids composition in the extracts can be a valuable resource for nutritional and cosmetic applications.

Biotechnological potential of the seaweed Cladophora rupestris (Chlorophyta, Cladophorales) lipidic extract

Recently, with the advent of modern technologies, various marine organisms including algae are being studied as sources of natural substances effective on classical microorganisms and able to also combat the new trend of acquired resistance in microbes. In the present study the antimicrobial activity of the lipidic extract of the green seaweed Cladophora rupestris collected in a Mediterranean area, in two sampling periods (January and April), was assayed. The chemical characterization of the lipidic fractions was performed by gas-chromatography and multinuclear and multidimensional NMR spectroscopy. In the lipidic extract of C. rupestris collected in January an antibacterial activity against Enterococcus sp., Streptococcus agalactiae and Vibrio cholerae non-O1 was recorded; by contrast, bacterial inhibition was measured on several Vibrio species only in April. The fatty acid profile of C. rupestris lipidic extract, analyzed by gas chromatography, resulted mainly composed of palmitic, myristic, oleic, α linolenic, palmitoleic and linoleic acids. Moreover, since α-linolenic acid was the predominant ω3 fatty acid in April, we suggest its involvement in the antibacterial activity observed in this month, taking also into account that pure α-linolenic acid resulted effective towards some vibrios strains. C. rupestris fatty acid profile revealed also an interesting composition in polyunsaturated fatty acids in both the considered periods with the ω6/ω3 ratio lower than 1, leading to conclude that this macroalga may be employed as a natural source of ω3. Finally, the (1)H NMR spectrum in CDCl3 of algal lipid fractions showed the characteristic signals of saturated (SAFAs) and unsaturated fatty acids (UFAs) as well as other metabolites and a marked difference in free fatty acids (FFAs) content for the two examined algal lipid fractions. It is noteworthy that C. rupestris lipidic extracts show, by NMR spectroscopy, the signal pattern of polyhydroxybutyrate, a natural biocompatible and biodegradable polymer. In conclusion, on account of its antimicrobial activity, nutritional value and bioplastic content, C. rupestris lipidic extract can be considered a promising source for future biotechnological applications.

The genus Dracunculus--a source of triacylglycerols containing odd-numbered ω-phenyl fatty acids

Reversed phase liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (RP-HPLC/MS-APCI) was used to identify and quantify triacylglycerols (TAGs) having odd-numbered ω-phenylalkanoic acids from seeds of the flower plant Dracunculus vulgaris, and TAGs from the bacterium Rhodococcus erythropolis prepared by precursor directed biosynthesis from phenylalanine and having the corresponding even-numbered ω-phenylalkanoic acids. Model compounds, which are not commercially available, were prepared by organic synthesis and this allowed us to extend the number of identified natural TAGs to nearly 140 molecular species. Both synthetic and natural compounds containing ω-phenylalkanoic acids were found to have antioxidant and free radical scavenging properties.

A Phenethyl bromo ester from Citharexylum fruticosum

A new compound, (2 S)- p-hydroxyphenethyl 2-bromo-2-methyldodeconate (1) and 7,3′-dimethoxy-5,4′-dihydroxy flavone, together with lupeol and stigmasterol were isolated from the stem bark of Citharexylum fruticosum (Verbenaceae). The structures of the compounds were established on the basis of the interpretation of NMR (1H, 13C, COSY and HMBC) spectra, as well as low and high-resolution mass spectrometric data. In this paper, we report on the structure elucidation of 1.

Polyketide synthases of bacterial symbionts in sponges--evolution-based applications in natural products research

Marine sponges are an unusually rich source of bioactive natural products with clinical potential. They also often harbor rich communities of symbiotic bacteria that have often been suspected as the true producers of sponge-derived compounds. To date, these bacteria can in most cases not be cultivated, but culture-independent methods, such as isolating and analyzing biosynthetic gene clusters using metagenomic strategies, have recently provided first insights into their chemical potential. This review summarizes recent work of our laboratory on the study of polyketide synthases (PKSs). These studies revealed two evolutionarily distinct, unusual PKS types that are commonly found in sponge metagenomes and were shown to be of bacterial origin. One, the sup PKS, dominates sponge metagenomic DNA libraries, occurs widespread in bacteriosponges and is to date exclusively known from such animals. Data suggest that it is a type of synthase that generates methyl-branched fatty acids, which are commonly present in sponges. The other PKS type, termed trans-acyltransferase (AT) PKS, is responsible for the biosynthesis of complex, bioactive polyketides, such as the onnamides, and also occurs in free-living bacteria. The diversity of PKS genes present in a single sponge metagenome can be enormous. However, the phylogenetic approaches outlined in this review can provide valuable insights into the PKS function and structures of polyketides and can assist in the targeted isolation of gene clusters.

Description of Labrenzia alexandrii gen. nov., sp. nov., a novel alphaproteobacterium containing bacteriochlorophyll a, and a proposal for reclassification of Stappia aggregata as Labrenzia aggregata comb. nov., of Stappia marina as Labrenzia marina comb. nov. and of Stappia alba as Labrenzia alba comb. nov., and emended descriptions of the genera Pannonibacter, Stappia and Roseibium, and of the species Roseibium denhamense and Roseibium hamelinense

A slightly pink-coloured strain, strain DFL-11T, was isolated from single cells of the marine dinoflagellate Alexandrium lusitanicum and was found to contain the genes encoding two proteins of the photosynthetic reaction centre, pufL and pufM. 16S rRNA gene sequence analysis revealed that the novel strain belonged to the α-2 subgroup of the Proteobacteria and was most closely related to Stappia aggregata (97.7 % similarity), Stappia alba (98.0 %) and Stappia marina (98.0 %). Dark-grown cells of strain DFL-11T contained small amounts of bacteriochlorophyll a (bchl a) and a carotenoid. Cells of strain DFL-11T were rods, 0.5–0.7×0.9–3.0 μm in size and motile by means of a single, subpolarly inserted flagellum. The novel strain was strictly aerobic and utilized a wide range of organic carbon sources, including fatty acids, tricarboxylic acid cycle intermediates and sugars. Biotin and thiamine were required as growth factors. Growth was obtained at sea salt concentrations of between 1 and 10 % (w/v), at a pH between 6 and 9.2 and at a temperature of up to 33 °C (optimum, 26 °C). Nitrate was not reduced and indole was not produced from tryptophan. Strain DFL11T was resistant to potassium tellurite and transformed it to elemental tellurium. The major respiratory lipoquinone was ubiquinone 10 (Q10). The polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, an unidentified aminolipid and the glycolipid sulphoquinovosyldiacylglyceride. The fatty acids comprised 16 : 1ω7c, 16 : 0, 18 : 1ω7c, 18 : 0, 11-methyl 18 : 1ω6t, 11-methyl 20 : 1ω6t, 20 : 1ω7c, 22 : 0, 22 : 1 and the hydroxy fatty acids 3-OH 14 : 0, 3-OH 16 : 0 (ester-linked), 3-OH 18 : 0, 3-OH 20 : 1 and 3-OH 20 : 0, all of which are amide-linked. The DNA G+C value was 56 mol%. Comparative analysis of α-2 subgroup 16S rRNA gene sequences showed that the type species of the genus Stappia, Stappia stellulata, is only distantly related to S. aggregata (95.3 % sequence similarity). Based on the combination of the 16S rRNA gene sequence data, a detailed chemotaxonomic study and the biochemical and physiological properties of members of the genera Stappia, Pannonibacter and Roseibium, it is proposed that S. aggregata, S. alba, S. marina are transferred to a new genus, Labrenzia gen. nov., as Labrenzia aggregata comb. nov., Labrenzia alba comb. nov. and Labrenzia marina comb. nov. The type species of the new genus is Labrenzia alexandrii sp. nov., with strain DFL-11T (=DSM 17067T=NCIMB 14079T) as the type strain. The pufLM genes of the photosynthesis reaction centre were shown to be present in some, but not all, species of the new genus Labrenzia and they were identified for the first time in S. stellulata. In accordance with the new data collected in this study, emended descriptions are provided for the genera Pannonibacter, Roseibium and Stappia.

Turkish freshwater and marine macrophyte extracts show in vitro antiprotozoal activity and inhibit FabI, a key enzyme of Plasmodium falciparum fatty acid biosynthesis

The ethanolic extracts of a number of Turkish freshwater macrophytes (Potamogeton perfoliatus, Ranunculus tricophyllus and Cladophora glomerata) and marine macroalgae (Dictyota dichotoma, Halopteris scoparia, Posidonia oceanica, Scinaia furcellata, Sargassum natans and Ulva lactuca) were assayed for their in vitro antiprotozoal activity. Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum were used as test organisms. The cytotoxicity of the extracts was also assessed against primary rat skeletal myoblasts (L6 cells). Whereas none of the extracts were active against T. cruzi, all crude extracts displayed appreciable trypanocidal activity against T. brucei rhodesiense, with S. natans being the most active one (IC(50) 7.4microg/ml). Except for the marine alga H. scoparia, all extracts also possessed leishmanicidal potential. The best antileishmanial activity was exerted by U. lactuca and P. oceanica (IC(50)'s 5.9 and 8.0microg/ml, respectively). Five extracts that demonstrated inhibitory activity towards P. falciparum (IC(50)'s 18.1-48.8microg/ml) were simultaneously assayed against FabI, a crucial enzyme of the fatty acid system of P. falciparum, to find out whether FabI was their target. The extracts of C. glomerata and U. lactuca efficiently inhibited the FabI enzyme with IC(50) values of 1.0 and 4.0microg/ml, respectively. None of the extracts were cytotoxic towards mammalian L6 cells. This work reports for the first time antiprotozoal activity of some Turkish marine and freshwater algae, as well as a target-based antiplasmodial screening for the identification of P. falciparum FabI inhibitors from aquatic and marine macrophytes.

Fatty acid profiling of microbial community during aging of mucilaginous aggregates in the northern Adriatic

Aggregates differing in size and phytoplankton community composition were sampled in winter/spring 2001 and summer 1997 and 2002 (during mucilaginous event) in the northern Adriatic Sea. The fatty acid profiles (FAME) were determined in aggregates, bacterial population was grown from each aggregate and each bacterial isolate from aggregate's plated cultures. All aggregates irrespective of the season, aggregate size or phytoplankton community composition contained isolates from three distinct groups, with fatty acid profiles corresponding to alpha-Proteobacteria, gamma-Proteobacteria and Cytophaga-Flavobacter (CF) complex but in different relative proportions. Fatty acid profiles of the bacterial population grown from each aggregate revealed either the domination of one group (gamma, alpha or CF) or contribution of more groups (gamma and CF; alpha and CF). Specifically, as the aggregates age a shift in favor of bacteria belonging to CF-complex and corresponding decrease in bacteria similar to that of Proteobacteria occur. During the aggregate aging process and degradation of the mucous matrix, besides bacterial succession, the phytoplankton growth took place inside the aggregates. Such an aging pattern was confirmed through laboratory experiments with aggregates inhabited by the diatom Cylindrotheca closterium.

A beta-amino acid containing tripeptide from a Pseudomonas-alteromonas bacterium associated with a black sea sponge

A novel tripeptide, 1, was isolated from the extracellular extract of a Pseudomonas-Alteromonas bacterium that was associated with the Black Sea sponge Dysidea fragilis. Compound 1 contains the novel beta-aminopimelic acid described for the first time from a natural product. The structure of 1 is suggested on the basis of the analysis of spectroscopic data and chemical degradation.

Metabolites from a marine bacterium Pseudomonas/Alteromonas, associated with the sponge Dysidea fragilis

The lipophylic extract from a Black Sea bacterium, associated with the sponge Dysidea fragilis, was investigated. Saturated hydrocarbons and fatty acids of the lipids were identified. The concentrations of the polycyclic compounds appeared to be negligible. The main components appeared to be phosphatidyl ethanolamine, followed by phosphatidyl serine. The first was investigated by FAB mass spectrometry and a series of molecular species partially identified.

Synthesis of racemic 9-methyl-10-hexadecenoic acid

The marine bacterial fatty acid 9-methyl-10-hexadecenoic acid was conveniently prepared in 6 steps and in a 22% overall yield, starting from commercially available methyl 10-hydroxydecanoate. The naturally occurring fatty acid has the E double bond configuration as confirmed by gas chromatographic co-elution experiments.

Fatty acid composition of bacteria associated with the toxic dinoflagellate Ostreopsis lenticularis and with Caribbean Palythoa species

The fatty acid composition of a Pseudomonas sp. (Alteromonas) and its host, the dinoflagellate Ostreopsis lenticularis, vectors in ciguatera fish poisoning, has been studied. The major fatty acids in O. lenticularis were 16:0, 20:5n-3, and 22:6n-3, but 18:2n-6, 18:3n-3, and 18:n-3 were also identified. In contrast to other dinoflagellates, 1 8:5n-3 was not detected in O. lenticularis. Even-chain fatty acids such as 9-16:1, 11-18:1, and 13-20:1 predominated in the Pseudomonas sp. from O. lenticularis, but 1 6-20% of (E)-11-methyl-12-octadecenoic acid was also identified. The chirality of the latter was confirmed by total synthesis (28% overall yield) starting from oxacyclotridecan-2-one. The fatty acid compositions of two other Pseudomonas species, from the palytoxin-producing zoanthids Palythoa mamillosa and P. caribdea, were also studied and were similar to that of the Pseudomonas sp. from O. lenticularis. The possibility of using some of these fatty acids as chemotaxonomic lipids in identifying marine animals that consume toxic dinoflagellates or zoanthids is discussed.