Cloning of flavonoid 3’,5’-hydroxylase and 3’-hydroxylase homologs from black currant(Ribes nigrum) and their differential expression at various fruit maturation stages

Flavonoid 3’-hydroxylase(F3’ H) and 3’,5’-hydroxylase(F3’5’ H) generate precursor molecules for the synthesis of cyanidin-based anthocyanins(red) and delphinidin-based anthocyanins(blue to purple) in Ribes nigrum L.(black currant). In this study, full-length 1780 and 165’-bp cDNA homologs of RnF3’5’ H1 and RnF3’ H1 from black currant were identified and cloned using a homologous cloning technique. Data revealed that Rn F3’5’ H1 and RnF3’ H1 are homologs that encode enzymes involved in anthocyanin synthesis from different plants,which phylogenetically cluster with the CYP75 B and CYP75 A families in the P45’ superfamily, respectively.The enzymes encoded by these two genes also shared a high homology with flavonoid hydroxylases identified from other plants. Furthermore, RnF3’5’ H1 and RnF3’ H1 levels were upregulated during fruit maturation. RnF3’5’ H1 levels were associated with both anthocyanin and soluble carbohydrate levels in blackcurrant, while RnF3’ H1 expression did not have such an association. The structure and expression patterns of RnF3’5’ H1 and RnF3’ H1 in blackcurrant were also characterized. Further studies should aid understanding of anthocyanin biosynthesis in black currant to develop molecular approaches and manipulate anthocyanin production in blackcurrant.

Cyclic oxidation behavior of Ni_(3)Al-based single crystal alloy IC21

In this study,the cyclic oxidation tests of the Ni3Al-based single-crystal super alloy IC21 were carried out at 800,900,950,1000,1050 and 1100℃in air.The present study shows that the complex oxide scale on the surface of the alloy is made up of an outer columnar NiO layer,an intermediate mixture of NiO and NiAl2O4layer with a small amount of Mo oxides and an inner continuous layer ofα-Al_(2)O_(3).The cyclic oxidation kinetics curves show that oxidation resistance at 800,900,950,1000 and1050℃seems to follow a similar law and is better than that at 1100℃.The overall weight changes at 1100℃follows a parabolic law.Spallation and severe rumpling of the oxide scale are observed on the surface of the alloy at1100℃,revealing the occurrence of disastrous oxidation.

Cellulose Acetate Thermoplastics with High Modulus, Dimensicnal Stability and Anti-migration Properties by Using CA-g-PLA as Macromolecular Plasticizer

Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.