Platelet‐activating factor detection,metabolism, and inhibitors in the ethanologenic bacterium Zymomonas mobilis

Platelet‐activating factor (PAF) is a signaling phospholipid with a significant physiological role in multicellular and unicellular organisms, including fermentative organisms such as yeast. Zymomonas mobilis is an ethanologenic α‐proteobacterium currently studied for bioethanol production. In order to examine the presence of PAF and/or PAF inhibitors in Z. mobilis, a new one‐step high performance liquid chromatography (HPLC) separation procedure of total lipids was performed, using a C8 reversed‐phase semi‐preparative column. According to this method and to bioassays based on washed rabbit platelet aggregation, two lipid molecules with PAF‐like activity and same retention times as those of standard PAF were detected; electron‐spray ionization MS and MS/MS analysis revealed that they share similar structure with 16:0 and 18:0 PAF. Furthermore, other lipids extracted from Z. mobilis were found to exhibit a potent anti‐PAF activity. Enzyme activities indicative of key PAF biosynthetic enzymes, such as dithiothreitol‐insensitive cholinephosphotransferase (PAF‐CPT) and lyso‐PAF acetyltransferase were detected in Z. mobilis homogenates. As for PAF degradation, activity similar to that of PAF acetylhydrolase was also discovered. Overall, the presence of PAF, PAF‐specific inhibitors, and enzyme activities relating to PAF metabolism, suggests that PAF may play an intrinsic role in this biotechnological organism. Practical applications: Z. mobilis is a platform microorganism for bioethanol production and a potential source of high‐value chemicals of interest to the food and healthcare industries. Further investigation of PAF's role is bound to affect applications involving this and other biotechnological organisms. The finding that Z. mobilis lipids exhibit potent anti‐PAF activity opens up prospects for their identification, overproduction and pharmaceutical use. The presented HPLC method for lipid fractionation accomplishes a one‐step separation of lipids from dense samples, which may be successfully employed to other lipid‐rich sources such as blood.     

Nitroxide‐mediated synthesis of styrenic‐based segmented and tapered block copolymers using poly(lactide)‐functionalized TEMPO macromediators

Poly(styrene)‐poly(lactide) (PS‐PLA), poly (tert‐butyl styrene)‐poly(lactide) (PtBuS‐PLA) diblocks, and poly(tert‐butyl styrene)‐poly(styrene)‐poly(lactide) (PtBuS‐PS‐PLA) segmented and tapered triblocks of controlled segment lengths were synthesized using nitroxide‐mediated controlled radical polymerization. Well‐defined PLA‐functionalized macromediators derived from hydroxyl terminated TEMPO (PLA_T) of various molecular weights mediated polymerizations of the styrenic monomers in bulk and in dimethylformamide (DMF) solution at 120–130°C. PS‐PLA and PtBuS‐PLA diblocks were characterized by narrow molecular weight distributions (polydispersity index (M_w/M_n) < 1.3) when using the PLA_T mediator with the lowest number average molecular weight M_n= 6.1 kg/mol while broader molecular weight distributions were exhibited (M_w/M_n = 1.47‐1.65) when using higher molecular weight mediators (M_n = 7.4 kg/mol and 11.3 kg/mol). Segmented PtBuS‐PS‐PLA triblocks were initiated cleanly from PtBuS‐PLA diblocks although polymerizations were very rapid with PS segments ～ 5–10 kg/mol added within 3–10 min of polymerization at 130°C in 50 wt % DMF solution. Tapering from the PtBuS to the PS segment in semibatch mode at a lower temperature of 120°C and in 50 wt % DMF solution was effective in incorporating a short random segment of PtBuS‐ran‐PS while maintaining a relatively narrow monomodal molecular weight distribution (M_w/M_n ≈ 1.5). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Enzymatic Synthesis of 1‐Alkyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate Using a Novel Lysoplasmalogen‐Specific Phopholipase D

Many phospholipase Ds (PLDs) are known to catalyze transphosphatidylation as well as hydrolysis of phospholipids. Transphosphatidylation of lysoplasmalogen (LyPls)‐specific phospholipase D (LyPls‐PLD), which catalyzes hydrolysis of ether lysophospholipids such as LyPls and 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine (Lyso‐PAF), still remains unclear. This study aims to reveal the transphosphatidylation activity of LyPls‐PLD, that is, the production of cyclic ether lysophospholipid. The enzymatic reaction is conducted in a buffer system, and the reaction products of a novel LyPls‐PLD from Thermocrispum sp. are investigated using mass spectrometry (MS). MS analyses demonstrate the reaction products to consist of 100% 1‐hexadecyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate (cLyPA) and choline from Lyso‐PAF; however, 1‐alkenyl‐2‐hydroxy‐sn‐glycero‐2,3‐cyclic‐phosphate from 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphocholine and 1‐O‐1′‐(Z)‐octadecenyl‐2‐hydroxy‐sn‐glycero‐3‐phosphoethanolamine is not produced. These results are expected to help in elucidating the catalytic mechanism of LyPls‐PLD, that is, the rate‐limiting step, and indicate LyPls‐PLD to be useful for the one‐pot synthesis of cLyPA. Practical Applications: A novel phospholipase D, LyPls‐PLD, can exclusively synthesize cLyPA from Lyso‐PAF using a one‐step enzymatic reaction without an organic solvent. cLyPA could be expected to show bioactivities similar to those of cyclic phosphatidic acid, which promotes normal cell differentiation, hyaluronic acid synthesis, antiproliferative activity in fibroblasts, and inhibitory activity toward cancer cell invasion and metastasis.     

Fatty acid profile changes during orange juice‐milk beverage processing by high‐pulsed electric field

High‐intensity pulsed electric fields (HIPEF) is an emerging non‐thermal food preservation technology which has the potential to pasteurize pumpable liquid foods. Its application is being studied to evaluate it as potential alternative or complementary process to thermal pasteurization. Orange juice‐milk beverage with added bioactive components is a ready‐to‐drink beverage developed as an alternative to traditional soft drinks. In the present work, two HIPEF treatments (35 and 40 kV/cm) and six different treatment times (from 40 to 180 µs) were evaluated to assess their effect on the fatty acid profile of an orange juice‐milk beverage fortified with n‐3 fatty acids and oleic acid. The effect of HIPEF treatment on various physicochemical properties of the beverages: pH, °Brix, hydroxymethylfurfural or peroxide index was also determined. After HIPEF treatment, non‐significant changes in the contents of saturated fatty acids, monounsaturated fatty acids or polyunsaturated fatty acids were observed. Neither peroxides nor intolerable levels of furfurals were detected. Only a small reduction in fat content (p <0.05) was found. In conclusion, HIPEF can be proposed as an alternative preservation technology due to these minimal changes which are negligible from the nutritional point of view.     

Intrinsic factor and vitamin B12 complex‐loaded poly[lactic‐co‐(glycolic acid)] microspheres: preparation,characterization and drug release

BACKGROUND: Vitamin B12 is an essential vitamin required by all mammals. Absorption of vitamin B12 is facilitated by binding of intrinsic factor–vitamin B₁₂ complex to specific receptors in the ileum. In humans a deficiency of this vitamin or a lack of intrinsic factor leads to pernicious anaemia. The major objective of the present study was to prepare intrinsic factor–vitamin B12 complex‐loaded poly[lactic‐co‐(glycolic acid)] (PLGA)‐based microparticles and to investigate their release kinetics. RESULTS: PLGA copolymer was synthesized by the ring‐opening polymerization method and characterized using gel permeation chromatography, Fourier transform infrared spectroscopy and ¹H NMR. The glass transition temperature measurement showed a single T_g at 40 °C. The intrinsic factor–vitamin B12 complex‐loaded PLGA microspheres were prepared by a water‐in‐oil‐in‐water double emulsion solvent extraction/evaporation technique. An environmental scanning electron microscopy investigation demonstrated that the PLGA particles had a mean particle diameter of 38 µm. Interestingly, different drug release patterns (bi‐ and triphasic ones) were observed for vitamin B12‐loaded and intrinsic factor–vitamin B12 complex‐loaded microspheres. In contrast to the rapid release of vitamin B12 by itself, in vitro release tests showed that intrinsic factor and vitamin B12 in the complex were released from PLGA microspheres in a sustained manner over 15 days. CONCLUSION: PLGA microspheres can be an effective carrier for the intrinsic factor–vitamin B12 complex. Copyright © 2007 Society of Chemical Industry     

Compatible and crystallization properties of poly(lactic acid)/poly(butylene adipate‐co‐terephthalate) blends

Differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXD) and dynamic mechanical analysis (DMA) properties of poly(lactic acid)/ poly(butylene adipate‐co‐terephthalate) (PLA/PBAT) specimens suggest that only small amounts of poor PLA and/or PBAT crystals are present in their corresponding melt crystallized specimens. In fact, the percentage crystallinity, peak melting temperature and onset re‐crystallization temperature values of PLA/PBAT specimens reduce gradually as their PBAT contents increase. However, the glass transition temperatures of PLA molecules found by DSC and DMA analysis reduce to the minimum value as the PBAT contents of PLA_xPBAT_y specimens reach 2.5 wt %. Further morphological and DMA analysis of PLA/PBAT specimens reveal that PBAT molecules are miscible with PLA molecules at PBAT contents equal to or less than 2.5 wt %, since no distinguished phase‐separated PBAT droplets and tan δ transitions were found on fracture surfaces and tan δ curves of PLA/PBAT specimens, respectively. In contrast to PLA, the PBAT specimen exhibits highly deformable properties. After blending proper amounts of PBAT in PLA, the inherent brittle deformation behavior of PLA was successfully improved. Possible reasons accounting for these interesting crystallization, compatible and tensile properties of PLA/PBAT specimens are proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Copolymerization of propylene with p‐allyltoluene using metallocene catalysts

Copolymerization of propylene with p‐allyltoluene (p‐AT) was performed using two metallocene catalysts, rac‐ethylenebis(indenyl)zirconium dichloride and rac‐dimethylsilylenebis[1‐(2‐methyl‐4‐phenylindenyl)]zirconium dichloride. The effects of the polymerization conditions, such as the amount of p‐AT in the feed and polymerization temperature, on the properties of the copolymers and the activity of the catalysts were investigated. With increasing p‐AT feed, the incorporation of p‐AT increased, but the activity of the metallocene catalyst, the melting temperature (T_m) and the number‐average molecular weight of the copolymers decreased. Higher polymerization temperature tended to enhance the activity of the metallocene catalyst and the incorporation of p‐AT. The copolymers produced using the two metallocene catalysts were characterized with ¹H NMR, ¹³C NMR and differential scanning calorimetry; the results showed that the copolymers had a random structure. Copyright © 2006 Society of Chemical Industry Society of Chemical Industry     

Riboflavin-photosensitized singlet oxygen oxidation product of vitamin D<Subscript>2</Subscript>

The riboflavin-photosensitized singlet oxygen oxidation of vitamin D₂ in a model system of 12% water and 88% acetone was studied to understand the possible oxidation of fortified vitamin D in milk. Only the samples containing vitamin D₂ and riboflavin under light storage showed two new peaks in the HPLC chromatogram, indicating that singlet oxygen oxidation of vitamin D₂ had occurred. UV analysis indicated that a new compound was formed from the reaction of the triene of vitamin D₂ with oxygen. The mass spectrum showed that one of the two compounds had a molecular ion at m/z=412, which was an increase of the mass of vitamin D₂ by the mass of exactly one oxygen. The IR spectrum suggested the presence of a hydroxyl group and no carbonyl group in the product. The combned information from UV, MS, and FTIR spectra and the chemical mechanisms of singlet oxygen oxidation of vitamin D₂ indicated that a 5,6-epoxide of vitamin D₂ was formed from vitamin D₂ in the presence of riboflavin under light.     

Exogenously Added Oxyphytosterols Do Not Affect Macrophage‐Mediated Inflammatory Responses

Although phytosterols, plant‐derived sterol‐like components, are well known for their cholesterol‐lowering properties, their atherogenic potential is still under debate. Although they are known to share structural similarities with cholesterol, it is unclear whether their oxidized forms (oxyphytosterols) have the capacity to mediate proinflammatory responses in macrophages. In the present study, bone marrow‐derived macrophages were treated with oxidized low‐density lipoproteins, oxyphytosterols (7keto‐sito/campesterol [7keto‐sit/camp] or 7‐beta‐hydroxy‐sito/campesterol [7βOH‐sit/camp]), nonoxidized phytosterol (β‐sitosterol), or carrier‐control (cyclodextrin) in a dose‐ and time‐dependent manner. Inflammatory cytokine release, activity, and the corresponding mRNA expression levels were analyzed. 7βOH‐sit/camp, rather than 7keto‐sit/camp, induced a modest proinflammatory response in wild‐type cells derived from C57Bl/6 mice. The observed mild inflammatory effects are independent of the low‐density lipoprotein receptor and Cluster of differentiation 36/Scavenger receptor‐a. These data suggest that exogenously added oxyphytosterols do not affect macrophage‐mediated inflammatory responses, at least in vitro.     

Synthesis and light‐emitting properties of a novel π‐conjugated poly[di(p‐phenyleneethynylene)‐alt‐ (p‐phenylenecyanovinylene)] containing n‐octyloxy side branches

A novel π‐conjugated poly[di(p‐phenyleneethynylene)‐alt‐(p‐phenylenecyanovinylene)] having n‐octyloxy side chains (PPE‐C₈PPE‐PPV) was prepared by polymerization of the monomer DEDB with BCN. Chemical structure of the polymer obtained was confirmed by ¹H NMR, FTIR, and EA. PPE‐C₈PPE‐PPV had a molecular weight enough to fabricate the electroluminescent (EL) device, and showed a good organosolubility, excellent thermal stability, and film‐forming property. In UV absorption and PL spectra in film it showed a maximum at 430 and 543 nm, respectively, which appeared 5 and 41 nm longer wavelengths than that of the solution, respectively. HOMO, LUMO energy levels and band gap were determined to be ?5.70, ?3.29, and 2.41 eV, respectively. Two EL devices with low‐work function cathodes were fabricated with the structures of ITO/PEDOT/PPE‐C₈PPE‐PPV/cathodes (LiF/Al and Mg:Ag/Ag). The both devices exhibited a bright green light emission at 545 nm and the maximum luminescence of 197 cd/cm² (LiF/Al) and 158 cd/cm² (Mg:Ag/Ag). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of racemization on stereocomplex‐induced gelation of water‐soluble polylactide–poly(ethylene glycol) block copolymers

Ring‐opening polymerization of L ‐ or D ‐lactide was realized at 140 °C for a period of 7 days in the presence of dihydroxyl poly(ethylene glycol) (PEG), with M?_n = 4000 g mol^?1, using zinc lactate as initiator. The resulting poly(L ‐lactide)–PEG–poly(L ‐lactide) and poly(D ‐lactide)–PEG–poly(D ‐lactide) triblock copolymers are water soluble with polylactide (PLA) block length ranging from 11 to 17 units. Both the tube inverting method and rheological measurements were used to evaluate the gelation properties of aqueous solutions containing single copolymers or L /D copolymer pairs. Stereocomplexation between poly(L ‐lactide) and poly(D ‐lactide) blocks is observed for mixed solutions. Hydrogel formation is detected in the case of relatively long PLA blocks (DP _PLA = 17), but not for copolymers with shorter PLA blocks (DP _PLA = 11–13) due to partial racemization of L ‐lactyl units. Racemization is largely reduced when the reaction time is shortened to 1 day. Under these conditions, DP _PLA of 8 is sufficient for the stereocomplexation of PLA–PEG block copolymers, and DP _PLA above 10 leads to the formation of hydrogels of PLA–PEG block copolymers. On the other hand, racemization appears as a general phenomenon in the (co)polymerization of L ‐lactide with Zn(Lac)₂ as initiator, although it is negligible or undetectable in the case of high molar mass polymers. Therefore, racemization is the limiting factor for the stereocomplexation‐induced gelation of water‐soluble PLA–PEG block copolymers where the PLA block length generally ranges from 10 to 30. Reaction conditions including initiator, time and temperature should be strictly controlled to minimize racemization. Copyright © 2010 Society of Chemical Industry     

Preparation of n‐3 Polyunsaturated Phosphatidylglycerol from Salmon Roe Lipids by Phospholipase D and In Vitro Digestion

Phosphatidylglycerol (PG) is a highly functional phospholipid (PL), which has many physiological functions. However, naturally occurring PG binding n‐3 polyunsaturated fatty acid (n‐3 PUFA) is low in content, resulting in a scarcity of industrial bio‐resources of n‐3 PUFA enriched PG. The current study investigates the preparation of salmon roe PG (SRPG) from three types of salmon roe lipids and glycerol via phospholipase D (PLD)‐mediated transphosphatidylation. The yields of SRPG obtained from salmon roe total lipid (SRTL) and salmon roe PL (SRPL) are higher than those obtained from purified salmon roe phosphatidylcholine (SRPC) in aqueous system. Following a 24 h reaction with 0.75 U PLD, SRTL, and SRPL yield up to 96.4 mol% and 96.7 mol% SRPG, respectively. In addition, more fatty acids are released from synthesized SRPG via hydrolysis by pancreatic enzymes than from SRPC and soybean PC in in vitro digestion model. Fatty acids at the sn‐2 position of SRPG are completely liberated by 0.04 U of phospholipase A₂ (PLA₂) during a 6 h reaction, whereas fatty acids of SRPC are partially unhydrolyzed even after a 24 h reaction. Our results suggest that SRPG converted from salmon lipids by PLD is a functional PL with high bioavailability of n‐3 PUFAs. Practical Applications: Phosphatidylglycerol rich in n‐3 PUFAs is prepared from salmon roe lipids (SRPG) catalyzed by PLD. The SRPG yields reach 96.4 mol% and 96.7 mol% of phosphatidylcholine contained in SRTL and SRPL, respectively, in aqueous reaction system. Fatty acids rich in n‐3 PUFAs at sn‐2 position of prepared SRPG are rapidly liberated by PLA₂ in an in vitro digestion model.     

<Emphasis Type="SmallCaps">l</Emphasis>-Carnitine/Simvastatin Reduces Lipoprotein (a) Levels Compared with Simvastatin Monotherapy: A Randomized Double-Blind Placebo-Controlled Study

Lipoprotein (a) [Lp(a)] is an independent risk factor for cardiovascular disease. There are currently limited therapeutic options to lower Lp(a) levels. l ‐Carnitine has been reported to reduce Lp(a) levels. The aim of this study was to compare the effect of l ‐carnitine/simvastatin co‐administration with that of simvastatin monotherapy on Lp(a) levels in subjects with mixed hyperlipidemia and elevated Lp(a) concentration. Subjects with levels of low‐density lipoprotein cholesterol (LDL‐C) >160 mg/dL, triacylglycerol (TAG) >150 mg/dL and Lp(a) >20 mg/dL were included in this study. Subjects were randomly allocated to receive l ‐carnitine 2 g/day plus simvastatin 20 mg/day (N = 29) or placebo plus simvastatin 20 mg/day (N = 29) for a total of 12 weeks. Lp(a) was significantly reduced in the l ‐carnitine/simvastatin group [?19.4%, from 52 (20–171) to 42 (15–102) mg/dL; p = 0.01], but not in the placebo/simvastatin group [?6.7%, from 56 (26–108) to 52 (27–93) mg/dL, p = NS versus baseline and p = 0.016 for the comparison between groups]. Similar significant reductions in total cholesterol, LDL‐C, apolipoprotein (apo) B and TAG were observed in both groups. Co‐administration of l ‐carnitine with simvastatin was associated with a significant, albeit modest, reduction in Lp(a) compared with simvastatin monotherapy in subjects with mixed hyperlipidemia and elevated baseline Lp(a) levels.     

Pyrrole‐based narrow‐band‐gap copolymers for red light‐emitting diodes and bulk heterojunction photovoltaic cells

A series of narrow‐band‐gap conjugated copolymers (PFO‐DPT) derived from pyrrole, benzothiadiazole, and 9,9‐dioctylfluorene (DOF) is prepared by the palladium‐catalyzed Suzuki coupling reaction with the molar feed ratio of 4,7‐bis(N‐methylpyrrol‐2‐yl)‐2,1,3‐benzothiadiazole (DPT) around 1, 5, 15, 30, and 50%. The obtained polymers are readily soluble in common organic solvents. The solutions and the thin solid films of the copolymers absorb light from 300 nm to 600 nm with two absorbance peaks at around 380 nm and 505 nm. The PL emission consists mainly of DPT unit emission at around 624–686 nm depending on the DPT content in solid film. The EL emission peaks are red‐shifted from 630 nm for PFO‐DPT1 to 660 nm for PFO‐DPT50. Bulk heterojunction photovoltaic cells fabricated from composite films of copolymer and [6,6]‐phenyl C₆₁ butyric acid methyl ester (PCBM) as electron donor and electron acceptor, respectively, in device configuration: ITO/PEDOT : PSS/PFO‐DPT : PCBM/Ba/Al shows power conversion efficiencies 0.15% with open‐circuit voltage (V_oc) of 0.60 V and short‐circuit current density (J_sc) of 0.73 mA/cm² under AM1.5 solar simulator (100 mW/cm²). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Recent Developments of 19‐Nor‐1,25‐dihydroxyvitamin D3 Analogues

The vitamin D hormone, 1α,25‐dihydroxyvitamin D₃ [1,25‐(OH)₂D₃], exerts its hormonal effects predominantly on intestine, bone, and kidney, where it plays a crucial role in calcium and phosphorus homeostasis and bone mineralization. In addition to its classical actions, 1,25(OH)₂D₃ exerts pleiotropic effects in a wide variety of target tissues and cell types, often in an autocrine/paracrine fashion. These biological activities of 1,25(OH)₂D₃ have suggested a multitude of potential therapeutic applications for the vitamin D hormone in the treatment of hyperproliferative disorders (e.g. cancer and psoriasis), immune dysfunction (autoimmune diseases), and endocrine disorders (e.g. hyperparathyroidism). However, the calcemic effects induced by 1,25(OH)₂D₃—hypercalcemia, increased bone resorption, and soft tissue calcification—limit the use of the natural ligand in these clinical applications. Therefore, numerous 1,25(OH)₂D₃ analogues have been synthesized with the intent of producing therapeutic agents devoid of hypercalcemic and hyperphosphatemic side effects. To this aim, much attention has been focused on the development of 19‐nor‐vitamin D₃ derivatives that lack the ring‐A exocyclic methylene group (C19). In this review, the 19‐nor‐1,25(OH)₂D₃ analogues are classified according to modifications made at the A‐ring, the side chain, or both the A‐ring and side chain, as well as other positions. The biological activities of these 19‐nor‐1,25(OH)₂D₃ analogues are summarized and their structure–activity relationships and binding features with the vitamin D receptor (VDR) are discussed.     

New Insights into the Anti‐Inflammatory and Antioxidant Properties of Nitrated Phospholipids

Nitro‐fatty acids (NO₂‐FA) have been widely studied with regard to their identification, structural characterization, and biological actions. NO₂‐FA could also be present endogenously esterified to phospholipids (PL), and NO₂‐PL were already detected in cardiac mitochondria from diabetic rats and cardiomyoblasts subjected to starvation. However, the biological actions of NO₂‐PL have been overlooked. In this study, we evaluate the antioxidant and anti‐inflammatory potential of the nitrated 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) formed in vitro by incubation with NO₂BF₄, in a well‐recognized mimetic model of nitroxidative stress. Nitrated POPC showed anti‐radical ability to reduce both 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH^?) (IC₂₀ = 225 ± 4 μg/mL; Trolox equivalent (TE) = 86 ± 6 μmol Trolox/g lipid) and 2,2′‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid radical cation (ABTS^?+) (IC₅₀ = 124 ± 2 μg/mL; TE = 152 ± 9 μmol Trolox/g lipid). Also, higher lag times were achieved in oxygen radical absorbance capacity (ORAC) assay for nitrated POPC, indicating a faster reaction with oxygen‐derived radicals (TE = 1.03 ± 0.22 and TE = 1.30 ± 0.16 mmol Trolox/g lipid for nonmodified and nitrated POPC, respectively). Nitrated POPC showed the ability to inhibit lipid oxidation induced by the hydroxyl radical generated under Fenton reaction conditions, monitored by electrospray ionization (ESI) mass spectrometry (MS) using phosphatidylcholine (PtdCho) liposomes as a model of cell membrane. Nitrated POPC showed anti‐inflammatory potential, as assessed by the inhibition of inducible nitric oxide synthase (iNOS) expression in RAW 264.7 macrophages activated by the Toll‐like receptor 4 (TLR4) agonist lipopolysaccharide (LPS) in a well‐described in vitro model of inflammation. Altogether, this study provides new clues regarding the antioxidant and anti‐inflammatory potential of nitrated POPC, which should be explored in depth.     

Synthesis and characterization of novel core‐shell magnetic nanogels based on 2‐acrylamido‐2‐methylpropane sulfonic acid in aqueous media

Ultrafine well‐dispersed Fe₃O₄ magnetic nanoparticles were directly prepared in aqueous solution using controlled coprecipitation method. The synthesis of Fe₃O₄/poly (2‐acrylamido‐2‐methylpropane sulfonic acid) (PAMPS), Fe₃O₄/poly (acrylamide‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid) poly(AM‐co‐AMPS) and Fe₃O₄/poly (acrylic acid‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid) poly(AA‐co‐AMPS) ‐core/shell nanogels are reported. The nanogels were prepared via crosslinking copolymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid, acrylamide and acrylic acid monomers in the presence of Fe₃O₄ nanoparticles, N,N′‐methylenebisacrylamide (MBA) as a crosslinker, N,N,N′,N′‐tetramethylethylenediamine (TEMED) and potassium peroxydisulfate (KPS) as redox initiator system. The results of FTIR and ¹H‐NMR spectra indicated that the compositions of the prepared nanogels are consistent with the designed structure. X‐ray powder diffraction (XRD) and transmission electron microscope (TEM) measurements were used to determine the size of both magnetite and stabilized polymer coated magnetite nanoparticles. The data showed that the mean particle size of synthesized magnetite (Fe₃O₄) nanoparticles was about 10 nm. The diameter of the stabilized polymer coated Fe₃O₄ nanogels ranged from 50 to 250 nm based on polymer type. TEM micrographs proved that nanogels possess the spherical morphology before and after swelling. These nanogels exhibited pH‐induced phase transition due to protonation of AMPS copolymer chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of the Human Milk Oligosaccharide Lacto‐N‐Tetraose in Metabolically Engineered,Plasmid‐Free E. coli

Human milk oligosaccharides (HMOs) constitute the third most abundant solid component of human milk. HMOs have been demonstrated to show positive effects on the infant’s well‐being. Despite numerous studies, more physiological analyses of single compounds are needed to fully elucidate these effects. Although being one of the most abundant core structures in human milk, the HMO lacto‐N‐tetraose (LNT) is not available at reasonable prices. In this study, we demonstrate the construction of the first E. coli strain capable of producing LNT in vivo. The strain was constructed by chromosomally integrating the genes lgtA and wbgO, encoding β‐1,3‐N‐acetylglucosaminyltransferase and β‐1,3‐galactosyltransferase. In shake‐flask cultivations, the strain yielded a total concentration of 219.1±3.5 mg L^?1 LNT (LNT in culture broth and the cell pellet). After recovery of LNT, structural analysis by NMR spectroscopy confirmed the molecule structure.     

Synthesis,photo‐, and electroluminescent properties of the soluble poly[(2,5‐diphenylene‐1,3,4‐oxadiazole)‐ 4,4′‐vinylene]

A novel soluble conjugated polymer, poly[(2,5‐diphenylene‐1,3,4‐oxadiazole)‐4,4′‐vinylene] (O‐PPV), containing an electron‐transporting group on the main chain of PPV, was synthesized according to HORNER mechanism. The oligo‐polymer with M_w = 1000 and T_d = 270°C is soluble in chloroform and tetrahydrofuran. The photoluminescent (PL) properties were investigated using different concentrations of solid‐state O‐PPV/PEO blends absorption and selective excitation measurements. The results show that PL arises from interchain charge‐transfer states in solid‐state O‐PPV. Compared with the analogous single‐layer device constructed with PPV (ITO/PPV/Al), which emits two peaks at λ = 520 nm and 550 nm (shoulder), the electroluminescence (EL) spectrum of the device [ITO/O‐PPV (80 nm)/Al] is a broad peak at λ_max = 509 nm. The quantum efficiency (0.13%) of the device ITO/O‐PPV/Al is much higher than that of the device ITO/PPV/Al, due to the introduction of the electron‐transporting group–oxadiazole units in the main chain of PPV. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3535–3540, 1999     

Anthranilic acid assisted preparation of Fe3O4–poly(aniline‐co‐o‐anthranilic acid) nanoparticles

Magnetic Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were prepared by a novel and simple method: anthranilic acid assisted polymerization. The synthetic strategy involved two steps. First, Fe₃O₄ nanoparticles capped by anthranilic acid were obtained by a chemical precipitation method, and then the aniline and oxidant were added to the modified Fe₃O₄ nanoparticles to prepare well‐dispersed Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles. Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles exhibited a superparamagnetic behavior (i.e., no hysteresis loop) and high‐saturated magnetization (M_s = 21.5 emu/g). The structure of the composite was characterized by Fourier‐transform infrared spectra, X‐ray powder diffraction patterns, and transmission electron microscopy, which proved that the Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were about 20 nm. Moreover, the thermal properties of the composite were evaluated by thermogravimetric analysis, and it showed excellent thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1666–1671, 2006