Soluble Metabolites Research Articles

Recruitment of specific flavonoid B-ring hydroxylases for two independent biosynthesis pathways of flavone-derived metabolites in grasses.

In rice (Oryza sativa), OsF2H and OsFNSII direct flavanones to independent pathways that form soluble flavone C-glycosides and tricin-type metabolites (both soluble and lignin-bound), respectively. Production of soluble tricin metabolites requires CYP75B4 as a chrysoeriol 5'-hydroxylase. Meanwhile, the close homologue CYP75B3 is a canonical flavonoid 3'-hydroxylase (F3'H). However, their precise roles in the biosynthesis of soluble flavone C-glycosides and tricin-lignins in cell walls remain unknown. We examinedCYP75B3 and CYP75B4 expression in vegetative tissues, analyzed extractable flavonoid profiles, cell wall structure and digestibility of their mutants, and investigated catalytic activities of CYP75B4 orthologues in grasses. CYP75B3 and CYP75B4 showed co-expression patterns with OsF2H and OsFNSII, respectively. CYP75B3 is the sole F3'H in flavone C-glycosides biosynthesis, whereas CYP75B4 alone provides sufficient 3',5'-hydroxylation for tricin-lignin deposition. CYP75B4 mutation results in production of apigenin-incorporated lignin and enhancement of cell wall digestibility. Moreover, tricin pathway-specific 3',5'-hydroxylation activities are conserved in sorghum CYP75B97 and switchgrass CYP75B11. CYP75B3 and CYP75B4 represent two different pathway-specific enzymes recruited together with OsF2H and OsFNSII, respectively. Interestingly, the OsF2H-CYP75B3 and OsFNSII-CYP75B4 pairs appear to be conserved in grasses. Finally, manipulation of tricin biosynthesis through CYP75B4 orthologues can be a promising strategy to improve digestibility of grass biomass for biofuel and biomaterial production.

Effect of Carbon/Nitrogen Ratio, Temperature, and Inoculum Source on Hydrogen Production from Dark Codigestion of Fruit Peels and Sewage Sludge

This paper studies the use of fruit peel biomass and waste sludge from municipal wastewater treatment plants in the metropolitan area of Monterrey, Mexico as an alternative way of generating renewable energy. Using a Plackett–Burman experimental design, we investigated the effects of temperature, inoculum source, and the C/N (Carbon/Nitrogen) ratio on dark fermentation (DF). The results indicate that it is possible to produce hydrogen using fruit peels codigested with sewage sludge. By adjusting the C/N ratio in response to the physicochemical characterization of the substrates, it was revealed that the quantities of carbohydrates and nitrogen were sufficient for the occurrence of the fermentation process with biogas production greater than 2221 ± 5.8 mL L−1Reactor and hydrogen selectivity of 23% (366 ± 1 mL H2·L−1Reactor) at the central point. The kinetic parameters (Hmax= 86.6 mL·L−1, Rm = 2.6 mL L−1 h−1, and λ = 1.95 h) were calculated using the modified Gompertz model. The quantification of soluble metabolites, such as acetic acid (3600 mg L−1) and ethyl alcohol (3.4 ± 0.25% v/v), confirmed the presence of acetogenesis in the generation of hydrogen.

Postprandial Skeletal Muscle Metabolism Following a High Fat Diet in Sedentary and Endurance Trained Males

ObjectiveFasting and postprandial metabolism are adversely affected by a sedentary lifestyle. However, the role of the prevailing diet remains unclear. The objective of the present study was to determine the influence of a high fat diet (HFD) on fasting and postprandial skeletal muscle substrate metabolism in sedentary compared with endurance trained (ET) humans.MethodsMetabolically healthy sedentary (n=17) and ET (n=7) males were control‐fed a 10‐day isocaloric moderate fat diet (30% fat [<10% saturated fat], 55% carbohydrate) followed by a 5‐day isocaloric HFD (55% fat [25% saturated fat], 30% carbohydrate). Before and after the HFD participants completed a high fat meal challenge (820 kcals; 63% fat [26% saturated fat], 25% carbohydrate) in which skeletal muscle biopsies were taken in the fasted and 4‐hour fed states. Complete fat, glucose, and pyruvate oxidation were assessed by measuring 14CO2 production in homogenized skeletal muscle incubated with radio‐labeled substrates. Incomplete fat oxidation was assessed by measuring 14C‐labeled acid soluble metabolites. Total fat oxidation was comprised of the sum of complete and incomplete fat oxidation. A substrate preference assay was performed by assessing the free fatty acid (FFA)‐induced suppression of [1‐14C]‐pyruvate oxidation. The meal effect for each substrate oxidation measure was calculated as the percent change from the fasted to 4‐hour fed state.ResultsThe meal effect for glucose oxidation was not altered by the HFD in the ET group (128 ± 92% vs. 41 ± 15%, P=0.375) but was reduced in the sedentary group (78 ± 26% vs. −21 ± 6%, P=0.002). The meal effect for pyruvate oxidation was similar between ET and sedentary groups before the HFD (34 ± 13% vs. 14 ± 17%, respectively; P=0.145) but was lower in the sedentary compared with the ET group after the HFD (−16 ± 6% vs. 24 ± 17%, P=0.047). The meal effect for substrate preference as indicated by FFA‐induced suppression of pyruvate oxidation was retained after the HFD in the ET group (20 ± 4% vs. 41 ± 21%, P=0.342) but was reduced in the sedentary group (34 ± 7% vs. 4 ± 5%, P=0.003). The meal effects for incomplete and total fat oxidation tended to decrease as a result of the HFD in the overall sample (P=0.075 and P=0.062, respectively). There were no physical activity group or HFD effects on meal effects for complete fat oxidation or the ratio of complete‐to‐incomplete fat oxidation.ConclusionsThese findings suggest skeletal muscle from sedentary individuals displays reduced postprandial glucose oxidation, yet pyruvate is preferred over fatty acids as an oxidative substrate following consumption of a HFD. These data highlight the need to better understand key regulatory nodes in skeletal muscle substrate metabolism between ET and sedentary humans.Support or Funding InformationADA‐07‐12 (MWH); Virginia Tech Translational Obesity Research IGEPThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Metabolism of Sulfamethoxazole by the Model Plant Arabidopsis thaliana.

Phytometabolism of antibiotics is a potentially significant route of human exposure to trace concentrations of antibiotics, prompting concerns about antibiotic resistance. The present study evaluated the metabolism of sulfamethoxazole (SMX), a commonly used sulfonamide antibiotic, by Arabidopsis thaliana. SMX was intensively metabolized by A. thaliana, with only 1.1% of SMX in plant tissues present as the parent compound after 10 days of exposure. Untargeted screening of extractable metabolites revealed that N-glycosylation was the main transformation pathway of SMX in A. thaliana plants, with N4-glycosyl-SMX accounting for more than 80% of the extractable metabolites. Additionally, N4-glycosyl-glycoside SMX accounted for up to 4.4% of the extractable metabolites, indicating glycosylation of N4-glycosyl-SMX. The majority of minor extractable SMX metabolites were also conjugates of the parent compound, such as pterin-SMX and methyl salicylate-SMX conjugates. In 14C-SMX trials, 14C-radioactivity was detected in both extractable and bound residues in plant tissues. Extractable residues, which included 14C-SMX and its soluble metabolites, accounted for 35.8-43.6% of the uptaken 14C-radioactivity, while bound residues were 56.4-64.2%. Approximately 27.0% of the initially applied 14C-radioactivity remained in the culture media at the conclusion of the experiments, composed of both 14C-SMX and its metabolites, likely due to plant excretion.

Soluble phenolics extracted from Larrea divaricata leaves modulate soil microbial activity and perennial grass establishment in arid ecosystems of the Patagonian Monte, Argentina

Sheep grazing induces the reduction of perennial grass cover and the increase of shrub cover with high concentration of chemical defences. We analysed the effects of secondary metabolites released from green and senesced leaves of the shrub Larrea divaricata on soil microbial activity and the establishment of perennial grasses in arid ecosystems of the Patagonian Monte. We carried out microcosm experiments with soil from plant patches without and with L. divaricata and inert substrate seeded with the perennial grasses Poa ligularis and Nassella tenuis, which are characteristic of the Patagonian Monte. Microcosms were subjected to three watering treatments: distilled water and aqueous extracts of green and senesced leaves of L. divaricata with high concentration of soluble phenolics. We assessed the microbial N-flush and net-N mineralization in soil, and seed germination, survival, and biomass of both perennial grass species. Aqueous leaf extracts led to a 29% increase in microbial N-flush and a 20% reduction in the net-N mineralization. Seed germination was less negatively affected by aqueous leaf extracts in P. ligularis ( < 18% reduction) than in N. tenuis (2–69% reduction). Survival of P. ligularis was not affected by aqueous leaf extracts while that of N. tenuis was 21–45% reduced only in the soil from plant patches without L. divaricata. Biomass accumulation of both perennial grass species was negatively affected by aqueous extracts of senesced leaves. We concluded that soluble metabolites extracted from L. divaricata may have positive or negative effects on microbial activity and potential allelopathic effects on perennial grass regeneration depending on species.

Highly Resolved Systems Biology to Dissect the Etioplast-to-Chloroplast Transition in Tobacco Leaves.

Upon exposure to light, plant cells quickly acquire photosynthetic competence by converting pale etioplasts into green chloroplasts. This developmental transition involves the de novo biogenesis of the thylakoid system and requires reprogramming of metabolism and gene expression. Etioplast-to-chloroplast differentiation involves massive changes in plastid ultrastructure, but how these changes are connected to specific changes in physiology, metabolism, and expression of the plastid and nuclear genomes is poorly understood. Here, we describe a new experimental system in the dicotyledonous model plant tobacco (Nicotiana tabacum) that allows us to study the leaf deetiolation process at the systems level. We have determined the accumulation kinetics of photosynthetic complexes, pigments, lipids, and soluble metabolites and recorded the dynamic changes in plastid ultrastructure and in the nuclear and plastid transcriptomes. Our data describe the greening process at high temporal resolution, resolve distinct genetic and metabolic phases during deetiolation, and reveal numerous candidate genes that may be involved in light-induced chloroplast development and thylakoid biogenesis.

Environment-dependent fitness gains can be driven by horizontal gene transfer of transporter-encoding genes

Many microbes acquire metabolites in a "feeding" process where complex polymers are broken down in the environment to their subunits. The subsequent uptake of soluble metabolites by a cell, sometimes called osmotrophy, is facilitated by transporter proteins. As such, the diversification of osmotrophic microorganisms is closely tied to the diversification of transporter functions. Horizontal gene transfer (HGT) has been suggested to produce genetic variation that can lead to adaptation, allowing lineages to acquire traits and expand niche ranges. Transporter genes often encode single-gene phenotypes and tend to have low protein-protein interaction complexity and, as such, are potential candidates for HGT. Here we test the idea that HGT has underpinned the expansion of metabolic potential and substrate utilization via transfer of transporter-encoding genes. Using phylogenomics, we identify seven cases of transporter-gene HGT between fungal phyla, and investigate compatibility, localization, function, and fitness consequences when these genes are expressed in Saccharomyces cerevisiae Using this approach, we demonstrate that the transporters identified can alter how fungi utilize a range of metabolites, including peptides, polyols, and sugars. We then show, for one model gene, that transporter gene acquisition by HGT can significantly alter the fitness landscape of S. cerevisiae We therefore provide evidence that transporter HGT occurs between fungi, alters how fungi can acquire metabolites, and can drive gain in fitness. We propose a "transporter-gene acquisition ratchet," where transporter repertoires are continually augmented by duplication, HGT, and differential loss, collectively acting to overwrite, fine-tune, and diversify the complement of transporters present in a genome.

High-resolution magic angle spinning nuclear magnetic resonance (HR-MAS-NMR) as quick and direct insight of almonds

Almonds are the tasty seeds of Prunus dulcis plants globally appreciated for the pleasant palatability and remarkable nutritional value, therefore it is very spread as snack and as basic ingredient of the confectionery products. The HR-MAS-NMR is a simple spectroscopy able to directly and quickly explore the chemical composition of powdered seed samples dispersed in D2O. 1H spectra witness the remarkable presence of triglyceride fatty esters together with sucrose; other minor water soluble metabolites are also detectable. This very rough approach is effectively providing chemical profiles featuring almond samples. In this analysis we were able to statistically distinguish the “Avola” almonds from other marketed products submitted to the same analysis. This is just a first investigation based on the main compounds but it might pave the way toward the quantitative evaluation of many other compounds in the almond therefore implementing the HR-MAS-NMR knowledge of these precious seeds.

Bioaugmentation with Thermoanaerobacterium thermosaccharolyticum W16 to enhance thermophilic hydrogen production using corn stover hydrolysate

In the present work, with corn stover hydrolysate as the substrate, an efficient hydrogen-producing thermophile, Thermoanaerobacterium thermosaccharolyticum W16, was added to three kinds of seed sludge (rotten corn stover (RCS), cow dung compost (CDC), and sludge from anaerobic digestion (SAD)) to investigate the effect of bioaugmentation on thermophilic hydrogen production. Batch test results indicate that the bioaugmentation with a small amount of the strain T. thermosaccharolyticum W16 (5% of total microbes) increased the hydrogen yield to varying degrees (RCS: from 8.78 to 9.90 mmol H2/g utilized sugar; CDC: from 8.18 to 8.42 mmol H2/g utilized sugar; SAD: from 8.55 to 9.17 mmol H2/g utilized sugar). The bioaugmentation process also influenced the soluble metabolites composition towards more acetate and less butyrate production for RCS, and more acetate and less ethanol accumulation for SAD. Microbial community analysis indicates that Thermoanaerobacterium spp. and Clostridium spp. dominated microbial community in all situations and might be mainly responsible for thermophilic hydrogen generation. For RCS and SAD, the bioaugmentation obviously increased the relative abundance of the strain T. thermosaccharolyticum W16 in microbial community, which might be the main reason for the improvement of hydrogen production in these cases.

Effect of temperature on the fermentation of starch by two high efficient H2 producers

The batch fermentative hydrogen production using starch was conducted to investigate the influence of temperature (25 °C-40 °C) on the co-cultures system of Bacillus cereus ATCC 14579 (T) [Strain A] and Brevundimonas naejangsanensis BIO-TAS2-2(T) [Strain B]. The results showed that the optimal temperature for hydrogen production was 35 °C in both the sole and the mixed culture fermentation. At this temperature, the co-culturing system increased the substrate consumption rate by 34 % and 70 % compared with the Strain A and Strain B fermentation, respectively. The co-culturing system enhanced the hydrogen production yield by 52 % and 62 % compared with the Strain A and Strain B fermentation, respectively. The analysis of soluble metabolites during the fermentation process indicated that the mixed acid fermentation conducted in two strains and co-culturing system was dominated by butyric acid type fermentation at the optimal temperature. The Formate pathway probably exists in Strain A, and the PFOR pathway probably exists in Strain B. Both strains A and B play a synergistic role in hydrogen production at 35 °C using starch as substrate.

Physical, but not chemical, antiherbivore defense expression is related to the clustered spatial distribution of tropical trees in an Amazonian forest.

The conspecific negative density dependence hypothesis states that mortality of young trees (seedlings and saplings) is higher near conspecific adults due to mechanisms such as allelopathy, intraspecific competition, and pest facilitation, explaining why in the tropics, most of plant species tend to be rare and live dispersed. However, there are some tree species that defy this expectation and grow in large clusters of conspecific juveniles and adults. We hypothesize that conspecifics living in clusters show higher and/or more variable defensive profiles than conspecifics with dispersed distributions.We evaluated our hypothesis by assessing the expression of physical leaf traits (thickness, and the resistance to punch, tear and shear) and leaf chemical defenses for six clustered and six non‐clustered tree species in Yasuní National Park, Ecuadorian Amazon. We ask ourselves whether (a) clustered species have leaves with higher physical resistance to damage and more chemical defenses variability than non‐clustered species; (b) saplings of clustered species may show higher physical resistance to damage and higher variation on chemical leaf defenses than their conspecific adults, and (c) saplings of non‐clustered species show lower resistance to physical damage and lower variation in chemical defenses compared to conspecific adults.Overall, our study did not support any of our hypotheses. Remarkably, we found that soluble metabolites were significantly species‐specific.Our study suggests that plants physical but not chemical leaf antiherbivore defenses may be a crucial strategy for explaining survivorship of clustered species. Trees in Yasuní may also fall along a suite of tolerance/escape/defense strategies based on limitations of each species physiological constraints for survival and establishment. We conclude that other mechanisms, such as those related to indirect defenses, soil nutrient exploitation efficiency, volatile organic compounds, delayed leaf‐greening, and seed dispersal mechanisms, shall be evaluated to understand conspecific coexistence in this forest.

Cerebrovascular Smooth Muscle Cells as the Drivers of Intramural Periarterial Drainage of the Brain.

The human brain is the organ with the highest metabolic activity but it lacks a traditional lymphatic system responsible for clearing waste products. We have demonstrated that the basement membranes of cerebral capillaries and arteries represent the lymphatic pathways of the brain along which intramural periarterial drainage (IPAD) of soluble metabolites occurs. Failure of IPAD could explain the vascular deposition of the amyloid-beta protein as cerebral amyloid angiopathy (CAA), which is a key pathological feature of Alzheimer's disease. The underlying mechanisms of IPAD, including its motive force, have not been clarified, delaying successful therapies for CAA. Although arterial pulsations from the heart were initially considered to be the motive force for IPAD, they are not strong enough for efficient IPAD. This study aims to unravel the driving force for IPAD, by shifting the perspective of a heart-driven clearance of soluble metabolites from the brain to an intrinsic mechanism of cerebral arteries (e.g., vasomotion-driven IPAD). We test the hypothesis that the cerebrovascular smooth muscle cells, whose cycles of contraction and relaxation generate vasomotion, are the drivers of IPAD. A novel multiscale model of arteries, in which we treat the basement membrane as a fluid-filled poroelastic medium deformed by the contractile cerebrovascular smooth muscle cells, is used to test the hypothesis. The vasomotion-induced intramural flow rates suggest that vasomotion-driven IPAD is the only mechanism postulated to date capable of explaining the available experimental observations. The cerebrovascular smooth muscle cells could represent valuable drug targets for prevention and early interventions in CAA.

Hydrogen Generation Performance from Taihu Algae and Food Waste by Anaerobic Codigestion

The rigid cell wall and low carbohydrate content of Taihu algae inhibit its application for hydrogen generation by anaerobic digestion (AD). In this study, algae was codigested with food waste (FW) in order to evaluate the influence of dried/wet condition and different mixing ratios on the digestion performance, where the dried algae (DA) showed an advantage over the wet algae (WA) by codigestion with FW. This was attributed to a suitable C/N ratio, more readily biodegraded organic substances, and microbial synergistic effect. The peak cumulative hydrogen production was 31.42 mL of H2/g volatile solid (VS) when the FW/DA ratio was 40:10, which was 12.13 times higher than that from DA only (2.59 mL/g VS). Meanwhile, the codigestion group of FW/DA (40:10) showed the best performance, contributing to the highest value of 82.06% for the carbohydrate degradation rate, 95.54% for the protein degradation rate, and 11.60 g/kg for the total soluble metabolite concentration. During the DA codigestion process, it wa...

Composition of Mycelia and Basidiomata of the Culinary-Medicinal Golden Oyster Mushroom, Pleurotus citrinopileatus (Agaricomycetes) by Nuclear Magnetic Resonance Spectroscopy.

Nuclear magnetic resonance (NMR) spectroscopy has been used to obtain the profile of soluble metabolites on fungus. To enhance the ergothioneine content in Pleurotus citrinopileatus mycelium, amino acid precursors were used for submerged fermentation. The study aimed to analyze the metabolites of high-ergothioneine and regular P. citrinopileatus mycelia (HEPM and RPM) and P. citrinopileatus basidiomata (PCB) using NMR spectroscopy. Principal component analysis (PCA) was applied to differentiate and to describe the differences among three sets of metabolites. The results showed that 55 water-soluble metabolites of PCB, HEPM, and RPM were identified and classified into five groups including amino acids, carbohydrates, organic acids, purines and pyrimidines, and others. Contents of total soluble metabolites were in descending order as follows: PCB (135 mg/g) > HEPM (58 mg/g) > RPM (44 mg/g). The score plot and loading plot separated using PCA showed that the first two components were responsible for R2X = 97.1% and the variance [R2X(1) = 74% for principal component PC1 and R2X(2) = 23.1% for PC2]. A metabolic pathway map of P. citrinopileatus mycelium was established and the differences in the metabolites of RPM and HEPM with precursors added were illuminated.

Studies on Qualitative and Quantitative Estimation of Primary and Secondary Metabolites in Various Solvents Extracts of &amp;lt;i&amp;gt;Aegle marmelos&amp;lt;/i&amp;gt;

The present study was an attempt to analyze the qualitative and quantitative analysis of phytochemical in different solvents extracts of A. marmelos. Primary metabolites like total soluble carbohydrates, proteins and secondary metabolites such as flavonoids, total phenols, and tannins were estimated using standard protocols. The qualitative and quantitative analysis is very essential for identifying and quantifying the compounds present in the medicinal plants. The results obtained from the present study provides evidence that various solvent extracts of A. marmelos leaves contains different types of primary and secondary metabolites which are having highly medicinal values and this justifies that the use of plant species as traditional medicine for treatment of various diseases. The finding of this study suggests that this plant leaves could be a potential source of natural medicine that could have great importance as therapeutic agents in preventing various diseases. The results are very much encouraging but scientific validation is necessary before being put in to practice. The present study suggest for future researcher on this plant that further Isolation, purification, characterization, structural elucidation and evaluation of a specific biological activity and preclinical and clinical studies of Bioactive compounds of this plant extracts were also necessary to emerge as medicine in the market.

Analysis of water soluble metabolites for orbital lymphoproliferative disease using metabolomics

Analysis of water soluble metabolites for orbital lymphoproliferative disease using metabolomics

Use of multivariate NMR analysis in the content prediction of hemicellulose, cellulose and lignin in greenhouse crop residues

We have introduced the use of multivariate NMR analysis in the development of accurate and robust prediction models, potentially arising from a correlation between soluble metabolite profiles and cell wall composition, for the determination of hemicellulose, cellulose and lignin contents in 8 species of greenhouse crop residues. The present paper demonstrates that discriminant buckets coming from a PLS-DA model in combination with linear models provide a useful and rapid tool for the determination of cell wall composition of these plant wastes. Regularized linear regression methods have also been applied to avoid overfitting, producing improved models specifically for lignin and cellulose determinations. The predictive models are also presented in a desktop application available at http://www2.ual.es/NMRMBC/solutions. To verify the rationality and reliability of the models, control experiments following generally accepted protocols have been performed and compared to our predicted values.

Boron: the essential element for vascular plants that never was.

Although a requirement for boron is a well-established feature of vascular plants, its designation, for almost a century, as essential is challenged and, instead, the proposal is made that it has never been so as conventionally defined. This is because an alternative interpretation of published evidence negates its compliance with one of the criteria for essentiality, that its effects are direct. The alternative, here postulated, is that boron is, and always has been, potentially toxic, a feature which, for normal growth, development and reproduction, needed to be nullified. This was enabled by exploitation of boron's ability to be chemically bound to compounds with cis-hydroxyl groups. Although particular cell wall carbohydrate polymers, glycoproteins and membrane glycolipids are among candidates for this role, it is here proposed that soluble phenolic metabolites of, or related to, the components of the pathway of lignin biosynthesis, themselves potentially toxic, are primarily used by vascular plants. When metabolic circumstances allow these phenolics to accumulate endogenously in the cytoplasm, their own inherent toxicity is also alleviated, partially at least, by formation of complexes with boron. This chemical reciprocity, enhanced by physical sequestration of the complexes in vacuoles and/or apoplast, thus achieves, in a flexible but indirect manner, a minimization of the inherent toxicities of both boron and relevant phenolics. In these ways, the multifarious outcomes of impairments, natural or experimental, to this interplay are responsible for the lackof consensus to explain the diverse effects observed in the manysearches for boron's primary metabolic role, here considered to be nonexistent. In particular, since a toxic element cannot have'deficiency symptoms', those previously so-called are postulated to be largely due to the expressed toxicity of phenylpropanoids. A principal requirement for the otherwise toxic boronis to nullify, by means of its indirect chemical and physicalsequestration, such expression. In these ways, it is therefore neither an essential nor a beneficial element as currently strictly defined.

Arachidonic Acid Induces the Migration of MDA-MB-231 Cells by Activating Raft-associated Leukotriene B4 Receptors.

The migration of tumor cells is critical in spreading cancers through the lymphatic nodes and circulatory systems. Although arachidonic acid (AA) and its soluble metabolites have been shown to induce the migration of breast and colon cancer cells, the mechanism by which it induces such migration has not been fully understood. The effect of AA on migratory responses of the MDA-MB-231 cell line (a triple-negative breast cancer cell) was examined and compared with MCF-7 (estrogen-receptor positive) breast cancer cells to elucidate the mechanism of AA-induced migration. Migrations of breast cancer cells were examined with the help of wound-healing assays. AA-induced eicosanoid synthesis was monitored by RP-HPLC. Cellular localizations of lipoxygenase and lipid rafts were assessed by immunoblot and confocal microscopy. AA treatment stimulated the synthesis of leukotriene B4 (LTB4) and HETE-8, but lowered the levels of prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), and HETE-5 in MDA-MB-231 cells. Further analysis indicated that AA increased the expression of 5-lipoxygenase (5-LOX) in this cell line and inhibiting its expression by small molecule inhibitors lowered the production of LTB4 and reduced migration. In contrast, MCF-7 cells did not show any appreciable changes in eicosanoid synthesis, 5-LOX expression, or cellular migration. Our results suggest that AA treatment activates the BLT1 receptor (present in membrane microdomains) and stimulates the synthesis of LTB4 production, which is likely to be associated with the migration of MDA-MB-231 cells.

Biodegradation of metal complex Naphthol Green B and formation of iron–sulfur nanoparticles by marine bacterium Pseudoalteromonas sp CF10-13

Treatment of metal complex dye wastewater has attracted growing attention due to the degradation-resistant, high cost and potential hazards of current techniques. This study reported a marine bacterium (Pseudoalteromonas sp CF10-13) with potential performance in decolorization and degradation of a metal complex dye—Naphthol Green B (NGB) at wide ranges of salinity, dye concentration and alkalinity under anaerobic conditions. It was inferred that the secretion of electron mediators in soluble extracellular metabolites by P. sp CF10-13 played important roles in NGB decolorization and degradation through extracellular electron transfer. Naphthalenesulfonate, the major structure in NGB molecule, was further degraded into low-toxic benzamide. Black stable iron–sulfur nanoparticles were formed endogenously avoiding H2S releasing, exogenous sulfur addition and metal sludge in accumulation. Accordingly, this study provided a cost-effective and eco-friendly biodegradation method to refractory NGB, further promoting the understanding of dye resources recovery.