18-carbon Fatty Acids Research Articles

Synthesis and Cytotoxicity Studies of Stilbene Long-Chain Fatty Acid Conjugates.

A series of 16 conjugates of the tubulin polymerization inhibitor combretastatin A4 (CA-4) and other functionally related stilbene with four 18-carbon fatty acids, namely, stearic, oleic, linoleic, and linolenic acids, have been synthesized in good yields. These new derivatives have been evaluated against the KB-3-1 (human epidermoid carcinoma), NCI-H460 (human lung cancer), HEK293 (human embryonic kidney), and MCF-7 (human breast adenocarcinoma) cell lines for antiproliferative activity, with the exhibited cytotoxic activities comparable with those of CA-4 and colchicine. Compounds 22 and 23, CA-4 conjugates of linoleic and linolenic acids, respectively, were determined to have exhibited the most active in vitro assays, with compound 23 exhibiting very similar activity to the parent compound against the NCI-H460 cell line. Our studies further delineated the structurally required Z-geometry of the stilbene moiety and that conjugation of the less active E-stilbenes with the most active fatty acid had minimal or no improvement in their respective activities.

2-Hydroxy-Docosahexaenoic Acid Is Converted Into Heneicosapentaenoic Acid via α-Oxidation: Implications for Alzheimer’s Disease Therapy

Alzheimer’s disease (AD) is a neurodegenerative disease with as yet no efficient therapies, the pathophysiology of which is still largely unclear. Many drugs and therapies have been designed and developed in the past decade to stop or slow down this neurodegenerative process, although none has successfully terminated a phase-III clinical trial in humans. Most therapies have been inspired by the amyloid cascade hypothesis, which has more recently come under question due to the almost complete failure of clinical trials of anti-amyloid/tau therapies to date. To shift the perspective for the design of new AD therapies, membrane lipid therapy has been tested, which assumes that brain lipid alterations lie upstream in the pathophysiology of AD. A hydroxylated derivative of docosahexaenoic acid was used, 2-hydroxy-docosahexaenoic acid (DHA-H), which has been tested in a number of animal models and has shown efficacy against hallmarks of AD pathology. Here, for the first time, DHA-H is shown to undergo α-oxidation to generate the heneicosapentaenoic acid (HPA, C21:5, n-3) metabolite, an odd-chain omega-3 polyunsaturated fatty acid that accumulates in cell cultures, mouse blood plasma and brain tissue upon DHA-H treatment, reaching higher concentrations than those of DHA-H itself. Interestingly, DHA-H does not share metabolic routes with its natural analog DHA (C22:6, n-3) but rather, DHA-H and DHA accumulate distinctly, both having different effects on cell fatty acid composition. This is partly explained because DHA-H α-hydroxyl group provokes steric hindrance on fatty acid carbon 1, which in turn leads to diminished incorporation into cell lipids and accumulation as free fatty acid in cell membranes. Finally, DHA-H administration to mice elevated the brain HPA levels, which was directly and positively correlated with cognitive spatial scores in AD mice, apparently in the absence of DHA-H and without any significant change in brain DHA levels. Thus, the evidence presented in this work suggest that the metabolic conversion of DHA-H into HPA could represent a key event in the therapeutic effects of DHA-H against AD.

Preliminary multi analytical approach to address geographic traceability at the intraspecific level in Scombridae family

ABSTRACT Globalization of seafood product marketing caused the increase of request of an effective fish traceability that enhances the consumer confidence in food safety. In this study, an integrated multi analytical approach based on two different and independent analytical techniques (carbon and nitrogen stable isotopes and fatty acids analysis) was applied in order to identify different fish species and trace their geographical provenience. The investigation was focused on four species (Thunnus thynnus, Thunnus alalunga, Auxis rochei and Scomber scombrus) belonging to the Scombridae family. The DNA barcoding method confirmed genus and species for S. scombrus and A. rochei, but only genus for T. alalunga and T. thynnus. Carbon and nitrogen stable isotopes results evidenced different fish diets and trophic positions, whereas fatty acids analysis displayed that the unsaturated prevailed (∼60 %) over the saturated compounds with a variation among the species and the geographical area in particular for docosahexaenoic and eicosapentaenoic acids percentage. The principal component analysis applied to stable isotopes and fatty acids evidenced a good discrimination among species and their geographical catching area. This multi-disciplinary analytical approach could represent a promising tool to identify the commercial fish and trace their origin in order to guarantee the health of consumers.

Relationship between bacterial compartment and particulate organic matter (POM) in coastal systems: An assessment using fatty acids and stable isotopes

Particulate organic matter (POM) in coastal systems is a mixture of different organic matter (OM) sources originating from land and sea. Among sources, bacterial biomass plays a large role in OM processing and carbon recycling in the ocean and is often neglected as a source in common approaches. The present study proposes to use elemental and isotopic ratio of carbon and nitrogen (C:N, δ13C, δ15N) and fatty acids to investigate the relationship between bacteria and surface water POM composition of three systems with different characteristics (two marine and one estuarine) over an annual cycle. Overall, our results highlight a positive relationship between bacterial contribution and continental degraded or undergoing degradation POM for all the studied systems and an inverse relationship with pelagic primary producers. At multisystem scale, high bacterial contribution is linked to high proportion of refractory terrestrial material characterizing estuarine stations whereas in marine systems, the occurrence of bacteria is mainly linked to river POM. Over the annual cycle, bacterial markers are more abundant during the winter period characterized by larger river and/or benthic POM contribution. This seasonal pattern is mainly driven by changes in river flows and resuspension. This study highlights the importance of bacterial compartment as a component of coastal and estuarine POM. Even though these results remains semi-quantitative, similar studies in other types of systems can help to understand microbial role in OM dynamic and to better estimate bacterial source in carbon budgets and food web studies.

Effects of high-starch or high-fat diets formulated to be isoenergetic on energy and nitrogen partitioning and utilization in lactating Jersey cows

The objective of this study was to determine the effects of high-starch or high-fat diets formulated to be isoenergetic on energy and N partitioning and utilization of energy. Twelve multiparous Jersey cows (mean ± standard deviation; 192 ± 11 d in milk; 467 ± 47 kg) in a crossover design with 28-d periods (24-d adaptation and 4-d collection) were used to compare 2 treatment diets. Treatments were high starch (HS; 30.8% starch, 31.8% neutral detergent fiber, and 1.9% fatty acids) or high fat (HF; 16.8% starch, 41.7% neutral detergent fiber, and 4.1% fatty acids). Diets were formulated to have net energy for lactation (NEL) content of 1.55 Mcal/kg of dry matter according to the National Research Council (2001) dairy model. Nutrient composition was varied primarily by replacing corn grain in HS with a rumen-inert fat source and cottonseed hulls in HF. Gross energy content was lower for HS (4.43 vs. 4.54 ± 0.01 Mcal/kg of dry matter), whereas digestible (2.93 vs. 2.74 ± 0.035 Mcal/kg of dry matter) and metabolizable energy (2.60 vs. 2.41 ± 0.030 Mcal/kg of dry matter), and NEL (1.83 vs. 1.67 ± 0.036 Mcal/kg of dry matter) content were all greater than for HF. Tissue energy deposited as body fat tended to be greater for HS (4.70 vs. 2.14 ± 1.01 Mcal/d). For N partitioning, HS increased milk N secretion (141 vs. 131 ± 10.5 g/d) and decreased urinary N excretion (123 vs. 150 ± 6.4 g/d). Compared with HF, HS increased apparent total-tract digestibility of dry matter (66.7 vs. 61.7 ± 1.06%), organic matter (68.5 vs. 63.2 ± 0.98%), energy (66.0 vs. 60.4 ± 0.92%), and 18-carbon fatty acids (67.9 vs. 61.2 ± 1.60%). However, apparent total-tract digestibility of starch decreased for HS from 97.0 to 94.5 ± 0.48%. Compared with HF, HS tended to increase milk yield (19.7 vs. 18.9 ± 1.38 kg/d), milk protein content (4.03 vs. 3.93 ± 0.10%), milk protein yield (0.791 vs. 0.740 ± 0.050 kg/d), and milk lactose yield (0.897 vs. 0.864 ± 0.067 kg/d). In addition, HS decreased milk fat content (5.93 vs. 6.37 ± 0.15%) but did not affect milk fat yield (average of 1.19 ± 0.09 kg/d) or energy-corrected milk yield (average of 27.2 ± 1.99 kg/d). Results of the current study suggest that the HS diet had a greater metabolizable energy and NEL content, increased partitioning of N toward milk secretion and away from urinary excretion, and may have increased partitioning of energy toward tissue energy deposited as fat.

N-myristoylation: from cell biology to translational medicine.

Various lipids and lipid metabolites are bound to and modify the proteins in eukaryotic cells, which are known as ‘protein lipidation’. There are four major types of the protein lipidation, i.e. myristoylation, palmitoylation, prenylation, and glycosylphosphatidylinositol anchor. N-myristoylation refers to the attachment of 14-carbon fatty acid myristates to the N-terminal glycine of proteins by N-myristoyltransferases (NMT) and affects their physiology such as plasma targeting, subcellular tracking and localization, thereby influencing the function of proteins. With more novel pathogenic N-myristoylated proteins are identified, the N-myristoylation will attract great attentions in various human diseases including infectious diseases, parasitic diseases, and cancers. In this review, we summarize the current understanding of N-myristoylation in physiological processes and discuss the hitherto implication of crosstalk between N-myristoylation and other protein modification. Furthermore, we mention several well-studied NMT inhibitors mainly in infectious diseases and cancers and generalize the relation of NMT and cancer progression by browsing the clinic database. This review also aims to highlight the further investigation into the dynamic crosstalk of N-myristoylation in physiological processes as well as the potential application of protein N-myristoylation in translational medicine.

Extraction and identification of toxic organic substances from decaying green alga Ulva prolifera

In this study, the extraction, identification, and antialgal activity of toxic organic substances from decaying green alga Ulva prolifera, a disaster-causing alga on green tides in the Yellow Sea, were investigated. The toxic organic substances of U. prolifera were isolated by a sequence of procedures, namely, liquid-liquid extraction (LLE), silica gel chromatography column separation (SGCC), C18 solid phase extraction (C18 SPE), and acid-alkali separation (AAS) and their antialgal activities were tested against diatom Skeletonema costatum. The results showed that the 96h-EC50 value in each procedure was 57.00 mg•L−1, 12.14 mg•L−1, 11.70 mg•L−1, and 6.31 mg•L−1 in turn. Additionally, the initial (ethyl acetate extract in LLE) and final (Organic phase A in AAS) yield of toxic organics were 318 mg•kg−1 and 9 mg•kg−1 (the wet weight of U. prolifera). The final active fractions were preliminary identified as five 16- and 18-carbon fatty acids and four enols using GC–MS. The study may further evaluate the effect of bioactive substances on marine life after U. prolifera green tides bloom.

Metabolic alterations in the erythrocyte during blood-stage development of the malaria parasite

BackgroundHuman blood cells (erythrocytes) serve as hosts for the malaria parasite Plasmodium falciparum during its 48-h intraerythrocytic developmental cycle (IDC). Established in vitro protocols allow for the study of host–parasite interactions during this phase and, in particular, high-resolution metabolomics can provide a window into host–parasite interactions that support parasite development.MethodsUninfected and parasite-infected erythrocyte cultures were maintained at 2% haematocrit for the duration of the IDC, while parasitaemia was maintained at 7% in the infected cultures. The parasite-infected cultures were synchronized to obtain stage-dependent information of parasite development during the IDC. Samples were collected in quadruplicate at six time points from the uninfected and parasite-infected cultures and global metabolomics was used to analyse cell fractions of these cultures.ResultsIn uninfected and parasite-infected cultures during the IDC, 501 intracellular metabolites, including 223 lipid metabolites, were successfully quantified. Of these, 19 distinct metabolites were present only in the parasite-infected culture, 10 of which increased to twofold in abundance during the IDC. This work quantified approximately five times the metabolites measured in previous studies of similar research scope, which allowed for more detailed analyses. Enrichment in lipid metabolism pathways exhibited a time-dependent association with different classes of lipids during the IDC. Specifically, enrichment occurred in sphingolipids at the earlier stages, and subsequently in lysophospholipid and phospholipid metabolites at the intermediate and end stages of the IDC, respectively. In addition, there was an accumulation of 18-, 20-, and 22-carbon polyunsaturated fatty acids, which produce eicosanoids and promote gametocytogenesis in infected erythrocyte cultures.ConclusionsThe current study revealed a number of heretofore unidentified metabolic components of the host–parasite system, which the parasite may exploit in a time-dependent manner to grow over the course of its development in the blood stage. Notably, the analyses identified components, such as precursors of immunomodulatory molecules, stage-dependent lipid dynamics, and metabolites, unique to parasite-infected cultures. These conclusions are reinforced by the metabolic alterations that were characterized during the IDC, which were in close agreement with those known from previous studies of blood-stage infection.

Effect of Carbon Nanostructures and Fatty Acid Treatment on the Mechanical and Thermal Performances of Flax/Polypropylene Composites.

Four different strategies for mitigating the highly hydrophilic nature of flax fibers were investigated with a view to increase their compatibility with apolar polypropylene. The effects of two carbon nanostructures (graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs)), of a chemical modification with a fatty acid (stearic acid), and of maleated polypropylene on interfacial adhesion, mechanical properties (tensile and flexural), and thermal stability (TGA) were compared. The best performance was achieved by a synergistic combination of GNPs and maleated polypropylene, which resulted in an increase in tensile strength and modulus of 42.46% and 54.96%, respectively, compared to baseline composites. Stearation proved to be an effective strategy for increasing the compatibility with apolar matrices when performed in an ethanol solution with a 0.4 M concentration. The results demonstrate that an adequate selection of surface modification strategies leads to considerable enhancements in targeted properties.

Meiobenthos as food for farmed shrimps in the earthen ponds: Implications for sustainable feeding

Shrimp farming in earthen pond is one of the largest seafood growing industries among coastal mariculture, but it has faced environmental issues in recent years, e.g. overloading of supplementary feed cause deterioration of pond environments. In order to assess the impact of pond shrimp farming on the benthic environment, we investigated the changes in environmental variables and meiobenthic community structure during January to August in the earthen ponds rearing Marsupenaeus japonicus and Litopenaeus vannamei. Water and sediment samples were taken in January (before aquaculture), May (early stage) and August (late stage). We found sedimentary redox potential showed values below −150 mV in all ponds in the early and late rearing stages, indicating overall reduced and anoxic conditions. Sedimentary bulk organic matter (total nitrogen and organic carbon) accumulated along with the feeding addition during the rearing period. We found meiobenthic community structure to change over different rearing stages mainly because of an increase in nematode densities that was associated with shrimp farming activity in the studied ponds. We also investigated the functional roles of pond biota and supplementary feed by studying the benthic food web in these ponds by means of natural stable isotope ratios of carbon and nitrogen and fatty acid biomarkers in the early (May) and late (August) rearing stages. Pond biota (i.e. microalgae and meiobenthos) contributed abundantly to the diets of the two shrimp species. In the early stage, meiobenthos shared similar diets with shrimps (with both feeding on primary organic sources) and they could thus potentially compete for resources. At late rearing stages, meiobenthos represented however a functional link between primary producers and shrimps, serving as nutritional food sources for shrimp and providing them high amounts of polyunsaturated fatty acids (PUFAs). We found that the supplementary feed was not substantially consumed by the two shrimp species, which might pose an overfeeding threat to deteriorate the pond environment.

Activation of RelA by pppGpp as the basis for its differential toxicity over ppGpp in Escherichia coli

The nucleotide derivatives (p)ppGpp, comprising ppGpp and pppGpp, are important signalling molecules that control various facets of gene regulation and protein synthesis in Escherichia coli. Their synthesis is catalysed by RelA (in response to amino acid limitation) and by SpoT (in response to the limitation of carbon source or fatty acids). SpoT is also a hydrolase for degradation of both ppGpp and pppGpp, while GppA catalyses the conversion of pppGpp to ppGpp. Here we provide evidence to show that pppGpp exerts heightened toxicity compared to that by ppGpp. Thus, gppA spoT double mutants exhibited lethality under conditions in which the single mutants were viable. The extent of RelA-catalysed (p)ppGpp accumulation in the gppA spoT strain was substantially greater than that in its isogenic gppA+ derivative. The data is interpreted in terms of a model in which toxicity of pppGpp in the gppA spoT mutants is mediated by its activation of RelA so as to result in a vicious cycle of (p)ppGpp synthesis.

Effect of fatty acid addition on properties of amylose nanoparticles prepared via complexing and precipitation

Amylose nanoparticles were prepared by complexing with fatty acids (palmitic acid, lauric acid and n-caproic acid) and then ethanol precipitation. The effects of the fatty acid addition and fatty acid carbon chain length on the size, crystallinity, morphology and fatty acid content of the complex nanoparticles were studied. Analyses of FT-IR, complexing index and 13C CP/MAS NMR suggested that amylose complexed with the fatty acids. The determined complexing indexes were 7.8 %, 36.2 % and 44.5 % for the n-caproic acid, lauric acid, and palmitic acid at the 10 % addition. The complexing index increased from 37.1%–44.7% for the palmitic acid when the addition was increased from 5 % to 20 %. XRD results showed that the complex nanoparticles possessed V-type crystalline structure, but the crystallinity decreased from 54.22%–36.38 % when the palmitic acid addition changed from 0 to 20 %. At the 10 % addition, the crystallinity decreased from 51.07%–42.15 % as fatty acid chain length increased from 6 carbon atoms to 16 carbon atoms. The result of 13C CP/MAS NMR analysis indicated that the fatty acid content in the complex nanoparticles increased with increasing of fatty acid chain length at 10 % addition. The findings of this study provide a guideline to prepare nanoparticles of amylose-fatty acid complexes with desired properties.

In-situ ammonia stripping with alkaline fermentation of waste activated sludge to improve short-chain fatty acids production and carbon source availability

Alkaline fermentation of waste activated sludge (WAS) to produce short-chain fatty acids (SCFAs) has been proved to be promising to develop internal carbon source for denitrifying processes in municipal wastewater treatment plants. However, a large amount of ammoniacal nitrogen also releases during fermentation, resulting in inhibition of acidogenic process and reduction of carbon source availability. Alkaline fermentation of WAS combined with in-situ ammonia stripping was proposed to improve SCFAs production and carbon source availability simultaneously. The results showed that a maximal SCFAs production of 308.7 ± 4.8 mg chemical oxygen demand/g volatile suspended solid was achieved under the pH = 10 + In-situ ammonia stripping, which was 21.7% and 141.5% higher than that of the pH = 10 and the control, respectively. Most of the ammoniacal nitrogen was stripped out, and the WAS-derived SCFAs availability as carbon source increased by 103.2%. These findings indicate in-situ ammonia stripping could make alkaline fermentation of WAS more practical.

The use of response surface methodology for improving fatty acid methyl ester profile of Scenedesmus vacuolatus.

The present study has been designed to optimise certain important process parameters for Scenedesmus vacuolatus to achieve efficient carbon dioxide extenuation as well as suitable fatty acid profile in context to improve biodiesel properties. The effect of varying sodium bicarbonate concentration was evaluated in single and multicomponent system such as nitrate, phosphate, inoculum size to observe interactive effects on algae biomass production, carbon dioxide (CO2) removal efficiency and fatty acid methyl ester (FAME) profile. Maximum biomass productivity of 117.0 ± 7.7mg/L/day with 3g/L of sodium bicarbonate was obtained i.e. approximately 2 folds higher than the control. Under multicomponent exposure, maximum biomass of 1701.5 ± 88.8mg/L and maximum chlorophyll concentration of 15.3 ± 6.4mg/L were achieved on 14th day at 3g/L sodium nitrate, 0.1g/L dipotassium hydrogen phosphate, 2g/L of sodium bicarbonate and initial cell density of 0.3 (N3P0.1B2OD0.3). FAME content of 46.1mg/g of biomass was obtained at this combination which is approximately 3 folds higher than the FAME content obtained under nitrogen and phosphate deprivation (16.6mg/g at N0P0B2OD0.3). Confocal microscopy images confirmed the results with enhanced lipid droplet accumulation at high bicarbonate concentration as compared with the control. This interactive study concluded the variability in FAME profile along with the exposure to varying nutrient concentrations.

Salicylic acid confers resistance against broomrape in tomato through modulation of C and N metabolism

It is well known that parasitic weeds such as Orobanche (broomrape) significantly decrease crop growth and yield. Although hormonal priming is a well-known inducer of plant resistance against broomrapes (Orobanche spp.), the metabolic events associated with such resistance are poorly understood. Therefore, the current work was undertaken to elucidate the role of SA in inducing tomato resistance against Orobanche, considering its impact on carbon and nitrogen metabolism of the host. Total carbon and nitrogen and levels of carbon (sugars, organic acids and fatty acids) and nitrogen (amino acids and polyamines)-containing metabolites as well as the activities of some key enzymes involved in their metabolic pathways were evaluated. Broomrape infection significantly disrupted C/N ratio in the host roots. On contrary, SA treatment markedly induced accumulation of sugars, organic acids, fatty acids, amino acids as well as polyamines in healthy plants. Under broomrape challenge, SA mitigated the infection-induced growth inhibition by improving the level of nitrogen-containing osmoprotectants (proline, arginine and some polyamines). However, a decrease was observed in some C and N assimilates which are well known to be potentially transferred to the parasite, such as sucrose, asparagine, alanine, serine and glutamate. Interestingly, SA treatment induced the catapolism of polyamines and fatty acids in the host root. Accordingly, our study suggests that SA-induced resistance against broomrape relies on the rational utilization of C and N assimilates in a manner that disturbs the sink strength of the parasite and/or activates the defense pool of the host.

Transcriptome analysis of Haematococcus pluvialis of multiple defensive systems against nitrogen starvation

Haematococcus pluvialis could accumulate large amounts of triacylglycerol (TAG) and astaxanthin under various environmental stresses. To gain insights into the multiple defensive systems for carbon metabolism against nitrogen starvation, transcriptome analysis was performed. It was found that the genes related to carbon fixation, glycolysis, fatty acid and carotenoid biosynthesis pathways were up-regulated remarkably. Glyceraldehyde 3-phosphate (G3P) biosynthesis was accelerated with the enhanced C3 and C4 pathway. Meanwhile, the pyruvate kinase (PK) and pyruvate dehydrogenase E2 component (aceF) genes were significantly increased 12.9-fold and 13.9-fold, respectively, resulting more pyruvate and acetyl-CoA generation, which were beneficial to carotenoids and fatty acid biosynthesis. Methylerythritol 4-phosphate (MEP) pathway mediated carotenoid precursor isopentenyl diphosphate (IPP) synthesis, as the all eight related genes were up-regulated. The carbon flux toward astaxanthin biosynthesis with the increased astaxanthin pathway genes. The redistribution of carbon was also promoted for TAG accumulation. In addition, the up-regulation of diacylglycerol acyltransferase (DGAT) and phospholipid: diacylglycerol acyltransferase (PDAT) genes indicated that both acyl-CoA dependent and independent pathway regulated TAG accumulation. Therefore, this work reveals the multiple defensive mechanism for carbon metabolism in response to nitrogen starvation, which extended our understanding on the carotenoids, TAG and other important metabolites synthesis.

More Favorable Palmitic Acid Over Palmitoleic Acid Modification of Wnt3 Ensures Its Localization and Activity in Plasma Membrane Domains.

While the lateral organization of plasma membrane components has been shown to control binding of Wnt ligands to their receptors preferentially in the ordered membrane domains, the role of posttranslational lipid modification of Wnt on this selective binding is unknown. Here, we identify that the canonical Wnt is presumably acylated by palmitic acid, a saturated 16-carbon fatty acid, at a conserved serine residue. Acylation of Wnt3 is dispensable for its secretion and binding to Fz8 while it is essential for Wnt3's proper binding and domain-like diffusion in the ordered membrane domains. We further unravel that non-palmitoylated Wnt3 is unable to activate Wnt/β-catenin signaling either in zebrafish embryos or in mammalian cells. Based on these results, we propose that the lipidation of canonical Wnt, presumably by a saturated fatty acid, determines its competence in interacting with the receptors in the appropriate domains of the plasma membrane, ultimately keeping the signaling activity under control.

Eicosanoid turnover (version 2019.5) in the IUPHAR/BPS Guide to Pharmacology Database

Eicosanoids are 20-carbon fatty acids, where the usual focus is the polyunsaturated analogue arachidonic acid and its metabolites. Arachidonic acid is thought primarily to derive from phospholipase A2 action on membrane phosphatidylcholine, and may be re-cycled to form phospholipid through conjugation with coenzyme A and subsequently glycerol derivatives. Oxidative metabolism of arachidonic acid is conducted through three major enzymatic routes: cyclooxygenases; lipoxygenases and cytochrome P450-like epoxygenases, particularly CYP2J2. Isoprostanes are structural analogues of the prostanoids (hence the nomenclature D-, E-, F-isoprostanes and isothromboxanes), which are produced in the presence of elevated free radicals in a non-enzymatic manner, leading to suggestions for their use as biomarkers of oxidative stress. Molecular targets for their action have yet to be defined.

Initial Characterization and Toxicology of an Nmt Inhibitor in Development for Hematologic Malignancies

N-myristoylation, the addition of the 14-carbon fatty acid to proteins, plays a fundamental role in cell signaling. Over 200 proteins are myristoylated, including the Src Family Kinases (SFK) Src, Lyn, Lck, Hck, and Fgr, as well as c-Abl, Gα subunits, caspase truncated (ct-) Bid and ct-PAK2, regulating cell growth and apoptosis. Human myristoylation is performed by two ubiquitously expressed N-myristoyl-transferases NMT1 and NMT2. PCLX-001 is a new, orally bioavailable, small-molecule, dual NMT inhibitor that is under investigation as a novel and selective treatment for B-cell malignancies. In vitro, PCLX-001 inhibits NMT1 and NMT2 at IC50 of 5nM and 8nM, respectively, inhibits the growth of hematological cancer cells at concentrations 10-fold lower than dasatinib and ibrutinib, and inhibits SFK recruitment to B cell receptor signaling, reducing survival signals and triggering apoptosis. PCLX-001 causes complete tumor regression in NOD/SCID mouse xenograft models of Acute Myeloid Leukemia (AML), Burkitts Lymphoma (BL), and Diffuse Large B-cell Lymphoma (DLBCL), including drug-resistant human tumor in a PDX model. When screened in vitro for its ability to inhibit the activity of 468 kinases and kinase mutants in a KINOMEscan®, PCLX-001 did not inhibit any kinase at up to 10 µM (5380 ng/mL) and produced modest inhibition of only three kinases (MRCKA, PIP5K2B, and SRPK1) at 100 µM (53800 ng/mL). Male rats tolerated single oral doses of PCLX-001 at 100 mg/kg without clear effects, but one of three rats died after a single dose at 1000 mg/kg. Dogs tolerated single oral doses of PCLX-001 at 10 mg/kg without effects, but both dogs showed emesis and diarrhea and lost weight after a single dose at 50 mg/kg. In 21-day xenograft efficacy studies in mice, the maximum tolerated dose level (MTD) was 50mg/kg, which also produced complete tumor remission of most xenografts. Administered daily, the 14-day MTD is >75mg/kg (highest dose tested) in rats and between 5 and 25mg/kg in dogs. The dose-limiting toxicities in dogs involved the gastrointestinal tract and hematopoietic bone marrow. When administered orally, PCLX-001 is 26% bioavailable in rats and >90% bioavailable in mice and dogs. The plasma half-life was 5.7h in mice, 1-2h in rats, and 3.9h in dogs. With repeated daily administration, systemic exposure did not change in dogs but decreased in rats. Based on KINOMEscan® results, PCLX-001 is very unlikely to produce adverse effects in patients due to off-target kinase inhibition. The oral bioavailability and half-life in mice and dogs are consistent with a once-a-day dosing regimen. Repeat dosing studies of up to 21 days in mice and 14 days in rats and dogs determined preliminary MTDs. When extrapolated to human doses based on a body surface area scaling, these MTDs are equivalent to 150mg/m2 in mice, >450mg/m2 in rats, and between 100 and 500 mg/m2 in dogs. These results are consistent with a therapeutic window with potential for tumor response in humans, and support proceeding with 28-day GLP toxicology studies and an IND filing for first in human testing of oral PCLX-001. Disclosures Weickert: Pacylex Pharmaceuticals, Inc.,: Employment. Mackey:Pacylex Pharmaceuticals Inc.: Equity Ownership, Patents & Royalties; illumiSonics Inc: Equity Ownership, Other: Director Role; Pfizer Canada: Honoraria; CME: Honoraria; SMHeartCard Inc: Equity Ownership, Other: Director Role. Berthiaume:Pacylex Pharmaceuticals, Inc.,: Equity Ownership, Patents & Royalties.

Phytoremediation of phenol by Hydrilla verticillata (L.f.) Royle and associated effects on physiological parameters

Phenol contamination is a common occurrence in aquatic environments in different parts of the world and strategies that utilize cheap and eco-friendly phytoremediation technologies are required to overcome associated environmental problems. In the present study, the submersed macrophyte Hydrilla verticillata (L.F.) Royle was exposed to different concentrations of phenol (0–200 mg L−1) to assess its potential in phenol treatment. H. verticillata efficiently degraded phenol in solutions with initial concentrations lower than 200 mg L−1. The adverse effects of phenol on physiological parameters of H. verticillata were also investigated after 7 d of phenol stress. In order to explore the effect of phenol on the metabolism of H. verticillata during phytoremediation, gas chromatography-mass spectrometry (GC–MS) was used to analyze endogenous soluble organic compounds. The results revealed the presence of greater than 60 soluble organic compounds in H. verticillata. In the process of phenol degradation, fatty acid composition and carbon number distribution were affected in the plants while unsaturated fatty acid content was significantly lower, and several compounds including aliphatic dicarboxylic acids and aromatic ketones were degraded while new compounds were synthesized by the plant. In summary, H. verticillata is a promising candidate for the phytoremediation of the phenol-contaminated aquatic system.