1.Long-chain acyl-CoA synthetase 2 knockdown leads to decreased fatty acid oxidation in fat body and reduced reproductive capacity in the insect Rhodnius prolixus.
Alves-Bezerra M1, Klett EL2, De Paula IF3, Ramos IB3, Coleman RA4, Gondim KC5. Biochim Biophys Acta. 2016 Apr 15. pii: S1388-1981(16)30103-2. doi: 10.1016/j.bbalip.2016.04.007. [Epub ahead of print]
Long-chain acyl-CoA esters are important intermediates in lipid metabolism and are synthesized from fatty acids by long-chain acyl-CoA synthetases (ACSL). The hematophagous insect Rhodnius prolixus, a vector of Chagas' disease, produces glycerolipids in the midgut after a blood meal, which are are stored as triacylglycerol in the fat body and eggs. We identified twenty acyl-CoA synthetase genes in R. prolixus, two encoding ACSL isoforms (RhoprAcsl1 and RhoprAcsl2). RhoprAcsl1 transcripts increased in posterior midgut on the second day after feeding, and RhoprAcsl2 was highly transcribed on the tenth day. Both enzymes were expressed in Escherichia coli. Recombinant RhoprACSL1 and RhoprACSL2 had broad pH optima (7.5-9.5 and 6.5-9.5, respectively), were inhibited by triacsin C, and were rosiglitazone-insensitive. Both showed similar apparent Km for palmitic and oleic acid (2-6μM), but different Km for arachidonic acid (0.5 and 6μM for RhoprACSL1-Flag and RhoprACSL2-Flag, respectively).
2.Oxycline formation induced by Fe(II) oxidation in a water reservoir affected by acid mine drainage modeled using a 2D hydrodynamic and water quality model - CE-QUAL-W2.
Torres E1, Galván L2, Cánovas CR2, Soria-Píriz S3, Arbat-Bofill M4, Nardi A5, Papaspyrou S3, Ayora C6. Sci Total Environ. 2016 Apr 16;562:1-12. doi: 10.1016/j.scitotenv.2016.03.209. [Epub ahead of print]
The Sancho reservoir is an acid mine drainage (AMD)-contaminated reservoir located in the Huelva province (SW Spain) with a pH close to 3.5. The water is only used for a refrigeration system of a paper mill. The Sancho reservoir is holomictic with one mixing period per year in the winter. During this mixing period, oxygenated water reaches the sediment, while under stratified conditions (the rest of the year) hypoxic conditions develop at the hypolimnion. A CE-QUAL-W2 model was calibrated for the Sancho Reservoir to predict the thermocline and oxycline formation, as well as the salinity, ammonium, nitrate, phosphorous, algal, chlorophyll-a, and iron concentrations. The version 3.7 of the model does not allow simulating the oxidation of Fe(II) in the water column, which limits the oxygen consumption of the organic matter oxidation. However, to evaluate the impact of Fe(II) oxidation on the oxycline formation, Fe(II) has been introduced into the model based on its relationship with labile dissolved organic matter (LDOM).
3.An Enantio- and Diastereoselective Chemoenzymatic Synthesis of α-Fluoro β-Hydroxy Carboxylic Esters.
Howard JK1, Müller M2, Berry A3, Nelson A4. Angew Chem Int Ed Engl. 2016 Apr 19. doi: 10.1002/anie.201602852. [Epub ahead of print]
The trans-o-hydroxybenzylidene pyruvate aldolase-catalysed reactions between fluoropyruvate and many (hetero)aromatic aldehydes yield aldol adducts without subsequent dehydration. Treatment of the reaction products with hydrogen peroxide yields the corresponding syn-configured α-fluoro β-hydroxy carboxylic acids which have >98 % ee. The overall chemoenzymatic approach, in which fluoropyruvate serves as a fluoroacetate equivalent, may be exploited in the synthesis of polar building blocks and fragments with potential value in drug discovery.
4.Protective effects of Weilikang decoction on gastric ulcers and possible mechanisms.
Wang S1, Ni Y1, Liu J1, Yu H2, Guo B3, Liu E1, He J2, Wang X1, Zhang Y4, Wang T5. J Nat Med. 2016 Apr 18. [Epub ahead of print]
Although Weilikang decoction (WLK) has been used for gastric ulcer (GU) therapy in a clinical setting with good curative effect for >20 years, the mechanism remains unclear. Several GU animal models, induced by ethanol, hydrochloric acid, aspirin, pylorus ligation, acetic acid and indomethacin, were used to investigate the gastroprotective effects of WLK decoction. Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME), indomethacin, and N-ethylmaleimide (NEM) were pretreated, respectively, to investigate the action mechanism. Real-time polymerase chain reaction and Western blot analysis methods were used to determine the effects of WLK on indomethacin-induced GUs. The WLK-administered groups (2.5, 1.25 and 0.625 g/kg) significantly reduced the GU areas induced by ethanol, hydrochloric acid and aspirin. Furthermore, the effects could be quenched by L-NAME and NEM, but not by indomethacin. The 2.5 and 1.25 g/kg WLK groups showed significantly decreased effects on GU areas induced by pylorus ligation and acetic acid.