Molar Basis Research Articles

A molar basis comparison of calcium hydroxide, sodium hydroxide, and potassium hydroxide on the pretreatment of switchgrass and miscanthus under high solids conditions

Pretreatment is an essential step in the formation of liquid biofuels. Switchgrass and miscanthus were pretreated using calcium hydroxide, potassium hydroxide, and sodium hydroxide at an equivalent hydroxyl concentration (0.46g OH−/g dry biomass), at a solids content of 40%, and two temperatures (25 and 50°C) for seven days. The cellulose, hemicellulose, and lignin composition before and after pretreatment were quantified according to the standard procedures developed by the National Renewable Energy Laboratory. After pretreatment, enzyme hydrolysis was performed at 50°C in a shaking incubator with an enzyme loading of 60 FPU/g cellulose. Potassium and sodium hydroxide led to the largest reduction in lignin of between 30–47% with the two feedstocks and two temperature levels. Calcium hydroxide had a significantly lower amount of delignification of between 13–21%. Sodium and potassium hydroxide had a similar maximum reaction rate, except for switchgrass pretreated at 50°C where the reaction rate was lower for potassium hydroxide. Cellulose conversion was the highest for sodium and potassium hydroxide and varied between 56.1 and 80.5% for both feedstocks at the two pretreatment temperatures investigated. Calcium hydroxide demonstrated a significantly lower cellulose conversion that varied between 23.0 and 44.9%. The results indicated that with an equivalent molar basis of OH−, potassium and sodium hydroxide had superior performance relative to calcium hydroxide in a high solids environment.

Experimental study of autoignition characteristics of Jet-A surrogates and their validation in a motored engine and a constant-volume combustion chamber

The current study presents an experimental validation of jet aviation fuel surrogates formulated using a surrogate model-optimizer. Two surrogate fuel mixtures are used to emulate a practical Jet-A (POSF 4658) considering a series of physical and chemical processes in diesel engines. The surrogate mixtures consist of: n-dodecane/isocetane/methylcyclohexane (MCH)/toluene 0.3844/0.1484/0.2336/0.2336 on a molar basis (referred to as UM I), and n-dodecane/isocetane/decalin/toluene 0.2897/0.1424/0.3188/0.2491 on a molar basis (referred to as UM II). In the present study, a modified Cooperative Fuels Research (CFR) Octane Rating engine and an optically accessible, constant-volume spray combustion chamber are employed to investigate how the chemical and physical properties of these jet fuel surrogate mixtures affect the fundamental ignition behavior as compared to the targeted full boiling range Jet-A fuel (POSF 4658). The observations of ignition behavior include critical compression ratio and critical equivalence ratio, and % low temperature heat release, which are assessed using the motored engine (CFR), while physical and chemical ignition delays are measured using a modified Cetane Rating (CID 510) instrument under a wide range of air temperatures and oxygen dilution levels.The measured derived cetane number (DCN) for UM I shows a reasonably good match with the practical Jet-A fuel (POSF 4658), while gas-phase oxidation behavior is less, well-matched in the modified CFR engine. In contrast, although the measured DCN of UM II revealed a lower value than the estimated value using a surrogate optimizer, the ignition behavior is relatively well match with that of the target Jet-A in the modified CFR engine. The similarities in physical and chemical ignition delays as compared with the target Jet-A support the effectiveness of the UM II surrogate, while in contrast, the UM I surrogate only matched the chemical ignition delay. This is attributed to the importance of the surrogate component decalin, which improved the physical properties as compared to MCH, while the other three components were the same for the two surrogates.

Abstract 2960: Potent in vivo activity of site-specific indolino-benzodiazepine antibody-drug conjugates (ADCs) generated via engineered cysteine conjugation

Abstract ADCs are widely studied for cancer therapy, with numerous agents in preclinical and clinical development embodying a wide array of targets, linker chemistries, and cytotoxic effector classes. A fourth element of ADC design that has received much attention recently is the site of conjugation of the cytotoxic molecule to the antibody. Historically, lysine- or interchain cysteine-directed conjugation has been used, but site-specific chemistries have become increasingly popular. Our previous evaluation of site-specific and lysine-linked ADCs utilizing a tubulin-acting maytansinoid effector molecule found the lysine-linked version was more active in vivo (Yoder et al., AACR 2015 #645). Here we present a comparison of engineered cysteine site-specific and lysine-linked ADCs utilizing the previously described indolino-benzodiazepine (henceforth referred to as IGN) effector IGN-P1 (Miller et al., AACR 2015 #652) which is designed to undergo proteolytic cleavage upon cell uptake to release a potently cytotoxic DNA alkylator. We show that HC-S442C mutants of human IgG1 can be conjugated via maleimide chemistry to IGN-P1 to give stable, potent, and homogeneous ADCs with drug to antibody ratio (DAR) of 2. The in vitro potency of engineered-cysteine IGN-P1 ADCs is largely dependent on the DAR of the ADC, although some difference is observed between HC-S442C and other cysteine mutants used for conjugation. Pharmacokinetic study of C442 maleimide conjugates suggests that the chemical linkage between effector and antibody is stable upon administration in mice. Further, and in contrast to our previous observations utilizing maytansinoid ADCs, the site-specific and Lys-linked IGN-P1 ADCs showed comparable efficacy in vivo on a molar drug basis. This effect was observed across two different antibodies targeting two different cell surface antigens. These results suggest that, in certain cases, site-specific conjugation chemistry can offer comparable activity to heterogeneous conjugation at well-tolerated doses. Citation Format: Nicholas C. Yoder, Chen Bai, Alan Wilhelm, Erin K. Maloney, Olga Ab, Emily E. Reid, Manami Shizuka, Daniel Tavares, Rassol Laleau, Xiuxia Sun, Megan E. Bogalhas, Lintao Wang, Jan Pinkas, Michael L. Miller, Ravi Chari, Thomas A. Keating. Potent in vivo activity of site-specific indolino-benzodiazepine antibody-drug conjugates (ADCs) generated via engineered cysteine conjugation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2960.

Characterization of total ecosystem-scale biogenic VOC exchange at a Mediterranean oak–hornbeam forest

Abstract. Recently, the number and amount of biogenically emitted volatile organic compounds (VOCs) has been discussed in great detail. Depending on the ecosystem, the published number varies between a dozen and several hundred compounds. We present ecosystem exchange fluxes from a mixed oak–hornbeam forest in the Po Valley, Italy. The fluxes were measured by a proton transfer reaction-time-of-flight (PTR-ToF) mass spectrometer and calculated using the eddy covariance (EC) method. Detectable fluxes were observed for up to 29 compounds, dominated by isoprene, which comprised over 60 % of the total upward flux (on a molar basis). The daily average of the total VOC upward flux was 10.4 nmol m−2 s−1. Methanol had the highest concentration and accounted for the largest downward flux. Methanol seemed to be deposited to dew, as the downward flux happened in the early morning, right after the calculated surface temperature came closest to the calculated dew point temperature.We estimated that up to 30 % of the upward flux of methyl vinyl ketone (MVK) and methacrolein (MACR) originated from atmospheric oxidation of isoprene. A comparison between two methods for the flux detection (manual and automated) was made. Their respective advantages and disadvantages were discussed and the differences in their results shown. Both provide comparable results.

Novel Approach for Evaluating Secondary Organic Aerosol from Aromatic Hydrocarbons: Unified Method for Predicting Aerosol Composition and Formation.

Innovative secondary organic aerosol (SOA) composition analysis methods normalizing aerosol yield and chemical composition on an aromatic ring basis are developed and utilized to explore aerosol formation from oxidation of aromatic hydrocarbons. SOA yield and chemical composition are revisited using 15 years of University of California, Riverside/CE-CERT environmental chamber data on 17 aromatic hydrocarbons with HC:NO ranging from 11.1 to 171 ppbC:ppb. SOA yield is redefined in this work by normalizing the molecular weight of all aromatic precursors to the molecular weight of the aromatic ring [Formula: see text], where i is the aromatic hydrocarbon precursor. The yield normalization process demonstrates that the amount of aromatic rings present is a more significant driver of aerosol formation than the vapor pressure of the precursor aromatic. Yield normalization also provided a basis to evaluate isomer impacts on SOA formation. Further, SOA elemental composition is explored relative to the aromatic ring rather than on a classical mole basis. Generally, four oxygens per aromatic ring are observed in SOA, regardless of the alkyl substitutes attached to the ring. Besides the observed SOA oxygen to ring ratio (O/R ∼ 4), a hydrogen to ring ratio (H/R) of 6 + 2n is observed, where n is the number of nonaromatic carbons. Normalization of yield and composition to the aromatic ring clearly demonstrates the greater significance of aromatic ring carbons compared with alkyl carbon substituents in determining SOA formation and composition.

Improved antithrombotic activity and diminished bleeding side effect of a PEGylated αIIbβ3 antagonist, disintegrin

IntroductionThe applicability of protein drugs is confined by protein degradation and rapid elimination. PEGylation of polypeptides improves protein stability by sterically obstructing the degradation by serum proteases and reduces renal clearance by the increased mass. Experimental approachWe compared the antithrombotic activities of intact rhodostomin (Rn) and PEGylated rhodostomin (PRn) both in vitro and in vivo systems. In addition, the functional half-life in inhibiting platelet aggregation and the tendency in causing bleeding side effect were investigated. ResultsRn and PRn both potently inhibited human and mouse platelet aggregation induced by collagen, thrombin or ADP in vitro with a similar IC50 around 60–100nM. Rotational thromboelastometry assay indicated that PRn was more effective than Rn in preventing clot formation in human whole blood. In platelet-rich plasma from mice injected with Rn or PRn, the inhibitory effects on collagen-induced platelet aggregation were also comparable, but Rn caused higher bleeding tendency. In ferric chloride-induced arterial thrombosis, Rn and PRn significantly prolonged occlusion time at high dosage (0.2μg/g). However, PRn obviously prolonged the occlusion time even given at a lower dosage (0.06μg/g). The functional half-life assay revealed that PEGylation prolonged the in vivo half-life of Rn. ConclusionsPRn exhibits higher antithrombotic potency and longer half-life in vivo as compared with native Rn on a molar basis. In addition, PRn exhibits a better safety profile at an efficacious antithrombotic dose in vivo. Therefore, PEGylation may be one of the ideal options in modifying disintegrin derivatives as the safe therapeutic agents for integrin-related diseases.

Deregulation of S-adenosylmethionine biosynthesis and regeneration improves methylation in the E. coli de novo vanillin biosynthesis pathway.

BackgroundVanillin is an industrially valuable molecule that can be produced from simple carbon sources in engineered microorganisms such as Saccharomyces cerevisiae and Escherichia coli. In E. coli, de novo production of vanillin was demonstrated previously as a proof of concept. In this study, a series of data-driven experiments were performed in order to better understand limitations associated with biosynthesis of vanillate, which is the immediate precursor to vanillin.ResultsTime-course experiments monitoring production of heterologous metabolites in the E. coli de novo vanillin pathway revealed a bottleneck in conversion of protocatechuate to vanillate. Perturbations in central metabolism intended to increase flux into the heterologous pathway increased average vanillate titers from 132 to 205 mg/L, but protocatechuate remained the dominant heterologous product on a molar basis. SDS-PAGE, in vitro activity measurements, and l-methionine supplementation experiments suggested that the decline in conversion rate was influenced more by limited availability of the co-substrate S-adenosyl-l-methionine (AdoMet or SAM) than by loss of activity of the heterologous O-methyltransferase. The combination of metJ deletion and overexpression of feedback-resistant variants of metA and cysE, which encode enzymes involved in SAM biosynthesis, increased average de novo vanillate titers by an additional 33 % (from 205 to 272 mg/L). An orthogonal strategy intended to improve SAM regeneration through overexpression of native mtn and luxS genes resulted in a 25 % increase in average de novo vanillate titers (from 205 to 256 mg/L). Vanillate production improved further upon supplementation with methionine (as high as 419 ± 58 mg/L), suggesting potential for additional enhancement by increasing SAM availability.ConclusionsResults from this study demonstrate context dependency of engineered pathways and highlight the limited methylation capacity of E. coli. Unlike in previous efforts to improve SAM or methionine biosynthesis, we pursued two orthogonal strategies that are each aimed at deregulating multiple reactions. Our results increase the working knowledge of SAM biosynthesis engineering and provide a framework for improving titers of metabolic products dependent upon methylation reactions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0459-x) contains supplementary material, which is available to authorized users.

1-Ethyl-3-methylimidazolium trifluoromethanesulfonate와 1-Butyl-1-methylpyrrolidinium trifluoromethanesulfonate 이온성 액체에 대한 황화수소와 메탄의 용해도

동일한 음이온을 가진 두 가지 종류의 이온성 액체인 1-ethy-3-methylimidazolium trifluoromethanesulfonate ([emim][TfO])와 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyr][TfO])를 대상으로 약 303 K로부터 약 343 K의 온도 범위와 약 30 MPa까지의 압력 범위에서 이온성 액체에 녹는 황화수소(<TEX>$H_2S$</TEX>)와 메탄(<TEX>$CH_4$</TEX>)의 용해도를 측정하였다. 가변부피투시창이 장착된 고압용 상평형 장치를 사용하여 온도를 변화시키면서 여러 가지 조성을 갖는 기체 + 이온성 액체 혼합물의 기포점 압력을 측정함으로써 이온성 액체에서의 기체의 용해도를 결정하였다. 이온성 액체에 대한 <TEX>$H_2S$</TEX>의 용해도는 압력이 증가함에 따라 증가하였으며 온도가 증가함에 따라 감소하였다. 반면에 이온성 액체에 대한 <TEX>$CH_4$</TEX>의 용해도는 압력이 증가함에 따라 크게 증가하였으나 온도의 영향은 거의 없었다. 동일한 음이온을 갖는 이온성 액체인 [emim][TfO]와 [bmpyr][TfO]에 대하여 <TEX>$H_2S$</TEX>의 용해도는 몰랄 농도 기준으로 온도 및 압력 조건에 관계없이 거의 유사하였다. 이온성 액체[emim][TfO]에 대한 <TEX>$H_2S$</TEX>와 <TEX>$CH_4$</TEX>의 용해도를 비교한 결과, <TEX>$H_2S$</TEX>의 용해도가 <TEX>$CH_4$</TEX>의 용해도보다 훨씬 컸다. 동일한 종류의 이온성 액체에 대하여 본 연구를 통해 얻은 <TEX>$H_2S$</TEX>와 <TEX>$CH_4$</TEX>의 용해도 데이터를 문헌으로부터 얻은 <TEX>$CO_2$</TEX>의 용해도 데이터와 비교하였다. 같은 압력 및 온도 조건에서 비교할 때, <TEX>$CO_2$</TEX>의 용해도는 <TEX>$H_2S$</TEX>와 <TEX>$CH_4$</TEX>의 용해도의 사이에 있었다. Solubility data of hydrogen sulfide (<TEX>$H_2S$</TEX>) and methane (<TEX>$CH_4$</TEX>) in two kinds of ionic liquids with the same anion: 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][TfO]) and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyr][TfO]) are presented at pressures up to about 30 MPa and at temperatures between 303 K and 343 K. The gas solubilities in ionic liquids were determined by measuring the bubble point pressures of the gas + ionic liquid mixtures with various compositions at different temperatures using a high-pressure equilibrium apparatus equipped with a variable-volume view cell. The <TEX>$H_2S$</TEX> solubilities in ionic liquid increased with the increase of pressure and decreased with the increase of temperature. On the other hand, the <TEX>$CH_4$</TEX> solubilities in ionic liquid increased significantly with the increase of pressure, but there was little effect of temperature on the <TEX>$CH_4$</TEX> solubility. For the ionic liquds [emim][TfO] and [bmpyr][TfO] with the same anion, the solubility of <TEX>$H_2S$</TEX> as a molality basis was substantially similar, regardless of the temperature and pressure conditions as a molar concentration basis. Comparing the solubilities of <TEX>$H_2S$</TEX> and <TEX>$CH_4$</TEX> in the ionic liquid [emim][TfO], the solubilities of <TEX>$H_2S$</TEX> were much greater than those of <TEX>$CH_4$</TEX>. For the same type of ionic liquid, the solubility data of <TEX>$H_2S$</TEX> and <TEX>$CH_4$</TEX> obtained in this study were compared to the solubility data of <TEX>$CO_2$</TEX> from the literature. When compared at the same pressure and temperature conditions, the <TEX>$CO_2$</TEX> solubility was in between the solubility of <TEX>$H_2S$</TEX> and <TEX>$CH_4$</TEX>.

Mercury species, selenium, metallothioneins and glutathione in two dolphins from the southeastern Brazilian coast: Mercury detoxification and physiological differences in diving capacity

In the present study, the concentration of trace elements, total mercury (Hg) and selenium (Se) and mercury forms (MeHg, Hginorg and HgSe) in the vulnerable coastal dolphins Pontoporia blainvillei and Sotalia guianensis were appraised and compared, using metallothioneins (MT) and glutathione (GSH) as biomarkers for trace element exposure. The trace element concentrations varied between muscle and liver tissues, with liver of all dolphin specimens showing higher Hg and Se concentrations than those found in muscle. Hg, MeHg and Hginorg molar concentrations showed a clear increase with Se molar concentrations in the liver of both dolphins, and Se concentrations were higher than those of Hg on a molar basis. Se plays a relevant role in the detoxification of MeHg in the hepatic tissue of both dolphins, forming Hg-Se amorphous crystals in liver. In contrast, MT were involved in the detoxification process of Hginorg in liver. GSH levels in P. blainvillei and S. guianensis muscle tissue suggest that these dolphins have different diving capacities. Muscle Hg concentrations were associated to this tripeptide, which protects dolphin cells against Hg stress.

Insulin Receptor Antibody-α-N-Acetylglucosaminidase Fusion Protein Penetrates the Primate Blood-Brain Barrier and Reduces Glycosoaminoglycans in Sanfilippo Type B Fibroblasts.

Mucopolysaccharidosis Type IIIB (MPSIIIB) is caused by mutations in the gene encoding the lysosomal enzyme, α-N-acetylglucosaminidase (NAGLU). MPSIIIB presents with severe disease of the central nervous system, but intravenous NAGLU enzyme replacement therapy has not been developed because the NAGLU enzyme does not cross the blood-brain barrier (BBB). A BBB-penetrating form of the enzyme was produced by re-engineering NAGLU as an IgG-enzyme fusion protein, where the IgG domain is a monoclonal antibody (mAb) against the human insulin receptor (HIR). The HIRMAb traverses the BBB via transport on the endogenous insulin receptor and acts as a molecular Trojan horse to ferry the fused NAGLU across the BBB from blood. The NAGLU was fused to the carboxyl terminus of each heavy chain of the HIRMAb via an extended 31-amino acid linker, and the fusion protein is designated HIRMAb-LL-NAGLU. The fusion protein retains high affinity binding to the HIR, and on a molar basis has an enzyme activity equal to that of recombinant human NAGLU. Treatment of MPSIIIB fibroblasts with the fusion protein normalizes intracellular NAGLU enzyme activity and reduces sulfate incorporation into intracellular glycosoaminoglycan. The fusion protein is targeted to the lysosomal compartment of the cells as shown by confocal microscopy. The fusion protein was radiolabeled with the [(125)I]-Bolton-Hunter reagent and injected intravenously in the adult Rhesus monkey. The fusion protein was rapidly cleared from plasma by all major peripheral organs. The high brain uptake of the fusion protein, 1% injected dose/brain, enables normalization of brain NAGLU enzyme activity with a therapeutic dose of 1 mg/kg. The HIRMAb-LL-NAGLU fusion protein is a new treatment of the brain in MPSIIIB, which can be administered by noninvasive intravenous infusion.

Effect of different struvite crystallization methods on gaseous emission and the comprehensive comparison during the composting

This study compared 4 different struvite crystallization process (SCP) during the composting of pig feces. Four combinations of magnesium and phosphate salts (H3PO4+MgO (PMO), KH2PO4+MgSO4 (KPM), Ca(H2PO4)2+MgSO4 (CaPM), H3PO4+MgSO4 (PMS)) were assessed and were also compared to a control group (CK) without additives. The magnesium and phosphate salts were all supplemented at a level equivalent to 15% of the initial nitrogen content on a molar basis. The SCP significantly reduced NH3 emission by 50.7–81.8%, but not the N2O. Although PMS group had the lowest NH3 emission rate, the PMO treatment had the highest struvite content in the end product. The addition of sulphate decreased CH4 emission by 60.8–74.6%. The CaPM treatment significantly decreased NH3 (59.2%) and CH4 (64.9%) emission and yielded compost that was completely matured. Due to its effective performance and low cost, the CaPM was suggested to be used in practice.

Reactions of Hydrogen Chloride with Carbonaceous Materials and the Formation of Surface Chlorine Species

Secondary reactions of hydrogen chloride (HCl) during high-temperature combustion processes were elucidated using a model carbon prepared from a commercially available phenol resin. This resin was O2-activated, followed by doping with K+, Ca2+, Cu2+, or Zn2+, and subsequently exposed to a stream of 100 ppm of HCl in N2 at 500 °C, during which HCl reacts with the carbon samples to form surface chlorine species. In the absence of metal cations, the extent of reaction increases almost linearly up to 500 °C as the number of carbon active sites, determined by temperature-programmed desorption, increases. The addition of Ca, Cu, or Zn but not K significantly promotes the formation of carbon sites as well as the reaction with HCl, with the latter effect increasing in the order of Ca < Cu < Zn on a molar basis. Cl 2p X-ray photoelectron spectroscopy (XPS) data show that inorganic chlorides of Ca, Cu, and Zn are formed and that the organic Cl/C ratio is 2.0–2.3 times greater when using these additives. It is thus ...

Effect of CO2 Addition on the Structure of Premixed Fuel-Rich CH4/O2/N2 and C3H8/O2/N2 Flames Stabilized on a Flat Burner at Atmospheric Pressure

The effect of replacement of 15% of N2 by CO2 (on a mole basis) in unburnt mixtures on the structure of laminar premixed methane/oxygen/nitrogen and propane/oxygen/nitrogen flames stabilized on a flat burner at 1 atm is studied. The emphasis of this work is on the effect of CO2 addition on the mole fractions of intermediates that are potential precursors of polycyclic aromatic hydrocarbons (PAH). Mole fraction profiles of reactants (CH4, C3H8, O2, and CO2), major intermediates (CH3, CH4, CH2O, C2H2, C2H3, C2H4, C2H6, C3H3, and C3H4) and final products (H2O, CO, CO2, and H2) in fuel-rich (φ = 1.2) CH4/O2/N2, CH4/O2/N2/CO2, C3H8/O2/N2, and C3H8/O2/N2/CO2 flames were measured using flame-sampling molecular beam mass spectrometry and calculated using the PREMIX code and three detailed chemical kinetic mechanisms reported in the literature for combustion of small hydrocarbons: AramcoMech 1.3, Konnov’s mechanism, and GRI-Mech 3.0. Temperature measurements in the flames were carried out using the thermocouple te...

A Hypersweet Protein: Removal of The Specific Negative Charge at Asp21 Enhances Thaumatin Sweetness.

Thaumatin is an intensely sweet-tasting protein that elicits sweet taste at a concentration of 50 nM, a value 100,000 times larger than that of sucrose on a molar basis. Here we attempted to produce a protein with enhanced sweetness by removing negative charges on the interacting side of thaumatin with the taste receptor. We obtained a D21N mutant which, with a threshold value 31 nM is much sweeter than wild type thaumatin and, together with the Y65R mutant of single chain monellin, one of the two sweetest proteins known so far. The complex model between the T1R2-T1R3 sweet receptor and thaumatin, derived from tethered docking in the framework of the wedge model, confirmed that each of the positively charged residues critical for sweetness is close to a receptor residue of opposite charge to yield optimal electrostatic interaction. Furthermore, the distance between D21 and its possible counterpart D433 (located on the T1R2 protomer of the receptor) is safely large to avoid electrostatic repulsion but, at the same time, amenable to a closer approach if D21 is mutated into the corresponding asparagine. These findings clearly confirm the importance of electrostatic potentials in the interaction of thaumatin with the sweet receptor.

ABCA1 agonist peptides for the treatment of disease.

The review summarizes information pertaining to the preclinical development of new apolipoprotein (apo) E mimetic peptides that stimulate cellular cholesterol efflux. Small α-helical peptides based on the C-terminal domain of apoE have been developed for therapeutic applications. These peptides stimulate cellular cholesterol efflux via the ATP-binding cassette transporter A1 (ABCA1) with high potency, like native apolipoproteins on a molar basis. This potent activity has been related to the unique ability of these peptides to maintain α-helix structure upon dilution. Recent structure-activity studies improving the safety features of these mimetic peptides have greatly improved their potential for clinical use. These studies have identified structural features of the class A α-helix motif that induce muscle toxicity and hypertriglyceridemia, which may have implications for the design of other HDL mimetic peptides. ABCA1 is an integral membrane protein that plays a central role in biology. Its principal function is to mediate the efflux of cholesterol and phospholipid from cells to extracellular apo, preventing a build-up of excess cholesterol in membranes. This process generates HDL particles that perform a variety of functions to protect against disease. A number of these functions can be viewed as directly or indirectly supporting ABCA1 activity, thus constituting a positive feedback system to optimize cellular lipid efflux responses and disease prevention. Consequently, therapeutic approaches that mimic the activities of apos may prove highly effective to combat disease. One such approach involves the use of peptides. The broad biological relevance of ABCA1 suggests these apo mimetic peptides may be useful for the treatment of a number of diseases, such as atherosclerosis, diabetes, and Alzheimer's disease.

Enrichment strategy for enhanced bioelectrochemical hydrogen production and the prevention of methanogenesis

The influence of acetate and butyrate enrichment on biofilm structure for enhanced electricity and hydrogen production was investigated using bioelectrochemical systems (BES). Two reactors were enriched for 9 weeks using 20 mM L−1 acetate (AC) and butyrate (BU) in microbial fuel cell mode before transfer into MECs. Acetate and butyrate (20, 10 and 5 mM L−1) substrates were sequentially used as feedstocks for the AC and BU acclimated reactors. Both BU and AC reactors gave initial hydrogen production rates of 200 ± 50 cm3STP/Lanode/day with a H2 yield of 0.585 ± 0.085 mol mol−1 but when the substrates were switched, the BU (MEC) hydrogen production rate increased to 249 ± 3.0 cm3STP/Lanode/day and the AC (MEC) decreased to 0 cm3STP/Lanode/day. It was demonstrated that the amount of methane produced by MEC (BU) was 58 ± 5% lower than that produced by MEC (AC). These results show that butyrate fed BES on an equivalent molar basis, improved MEC bioanodic performance and demonstrated the potential to improve overall performance of an integrated hydrogen fermentation and BES system.

Nutritional indexes, fatty acids profile, and regiodistribution of oil extracted from four discarded species of the Alboran Sea: Seasonal effects

The new EU fisheries regulations state that all catches from pelagic fisheries must be landed from the January 1, 2015 on. Consequently, the development of new techniques for the up‐grading of these discards is required. The aim of this work was to study the variations of the lipid profile and nutritional value of the oil extracted from four discarded species: axillary seabream (Pagellus acarne), sardine (Sardina pilchardus), horse mackerel (Trachurus mediterraneus), and blue whiting (Micromesistius poutassou). To that end, the proximate composition, the lipid profile, the regiospecific distribution of fatty acids within the glycerol backbone, the nutritional parameters (thrombogenic and atherogenicity indexes and hypocholesterolemic/hypercholesterolemic ratio), and the peroxidability index were determined in each season. All species presented polyunsaturated fatty acids (PUFA) as the major fraction in both the global and the sn‐2 profile. DHA presented highly regiospecifity to position sn‐2 whereas the tendency of EPA was to occupy sn‐1(3) positions. The relative concentration of PUFA occupying sn‐2 position varied from 30 to 60% (molar basis).Practical applications: This work proposes an up‐grading strategy for the fish oils extracted from four discarded pelagic species. In the last decades, fish oils have been widely employed as source for the production of structured lipids or PUFA concentrates. The choice between both applications depends on the fatty acids regiodistribution within the glycerol backbone. Oils with high PUFA content at the central bond may be selected for the production of structured lipids by using sn1‐3 lipases. In this case, the central position remains unmodified. To obtain concentrates it is necessary to release the free fatty acids and subsequently re‐esterified them. Consequently, oils with lower PUFA content in the central position are preferred for the production of concentrates by urea complexation or winterization.Seasonal variation of the percentage of DHA located at the sn‐2 position of four discarded species (axillary seabream, sardine, horse mackerel, and blue whiting).

Monodispersed strontium containing bioactive glass nanoparticles and MC3T3-E1 cellular response

AbstractNon-porous monodispersed strontium containing bioactive glass (Si2O-CaO-SrO) nanoparticles (Sr- BGNPs), were synthesised using a modified Stöber process. Silica nanoparticles (Si-NPs) with diameters 90 ± 10 nm were produced through hydrolysis and polycondensation reactions of the silicon alkoxide precursor, tetraethyl orthosilicate (TEOS), prior to the incorporation of cations; calcium (Ca) and strontium (Sr), into the silica networks through heat treatment (calcination). Sr was substituted for Ca on a mole basis from non- (0SrBGNPs) to fullsubstitution (100SrBGNPs) in order to increase the amount of network modifiers in the Si-NPs. The different ratios of Si: Ca; 1:1.3 and 1:8.0, presented various elemental compositions (i.e. 77–92 mol% of SiO

Insulinotropic action of bombesin-like peptides mediated by gastrin-releasing peptide receptors in steers.

The present study characterizes the receptor that mediates the insulinotropic action of bombesin-like peptides (BLP) in ruminants. Eight Holstein steers were randomly and intravenously injected with synthetic bovine gastrin-releasing peptide (GRP; 0.9 nmol/kg BW), neuromedin B (NMB; 0.9 nmol/kg BW), or neuromedin C (NMC; 0.9 nmol/kg BW), each alone or combined with the antagonist of GRP receptors N-acetyl-GRP-OCHCH (N-GRP-EE; 22.5 nmol/kg BW) or the antagonist of GH secretagogue receptor type 1a (GHS-R1a) [D-Lys]-GHRP-6 (21.5 nmol/kg BW). Blood samples were collected at -10, 0 (just before injection), 5, 10, 15, 20, 30, 45, 60, 75, and 90 min relative to injection time. Levels of injected peptides, insulin, and glucose in plasma were analyzed. Results showed that the peak of insulin levels was seen at 5 min after injection of NMC or GRP. Plasma glucose was observed in 2 phases; a significant rise followed a remarkable fall after NMC or GRP administration compared with injection of the vehicle ( < 0.05). On a same molar basis, effects of GRP on insulin and glucose were more potent than those of NMC ( < 0.05). The NMC-induced changes of insulin and glucose were completely blocked by N-GRP-EE, but [D-Lys]-GHRP-6 did not block any of these changes. Administration of NMB or N-GRP-EE alone did not change the circulating levels of insulin or glucose during any of the sampling time points ( > 0.05). These results indicated that the insulinotropic action of BLP is mediated by GRP receptors but not through a ghrelin/GHS-R1a pathway and that BLP may be involved in the regulation of glucose homeostasis in ruminants.

Carbon dioxide uptake as ammonia and amine carbamates and their efficient conversion into urea and 1,3-disubstituted ureas

Solid mixtures of ammonium carbamate and bicarbonate originating from the CO2 capture by NH3 in water–ethanol solution were converted into urea by heating to 428K for 60–90min. The yield of urea was up to 53% on molar basis. An analogous technique was employed to capture CO2 with 1-aminobutane, 1-amino-2-methylpropane, 2-amino-2-methylpropane, 1-aminooctane, aminocyclohexane and 1,4-diazacyclohexane, in organic solvents as amine carbamates which were separated in the solid state and thermally converted at 423K for 15–16h into 1,3-disubstituted ureas with 30–40% yield on molar scale. The formation of 1,3-disubstituted ureas was 100% selective. The rate of the conversion reaction was significantly improved in the presence of copper catalysts. The identification and quantification of the products in the reaction mixtures were obtained by 13C NMR analysis.