The Identification of Phenylalanine Ammonia-Lyase(PAL)Genes from Pinus yunnanensis and an Analysis of Enzyme Activity in vitro

Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.

Effects of Lactobacillus plantarum and fibrolytic enzyme on the fermentation quality and in vitro digestibility of total mixed rations silage including rape straw

The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutritive characteristics and in vitro digestibility of total mixed ration（TMR） silages containing 0, 7.5 and 15.0%（on dry matter basis） of rape（Brassica campestris L.） straw（RS）（denoted as CTMR, LTMR and MTMR, respectively）. After ensiling for 60 days, TMR silages without additives were well preserved, but MTMR had higher p H than CTMR and LTMR. There were no differences in other parameters of fermentation quality, microbial composition, nutrition and in vitro digestibility between CTMR and LTMR except for yeast and mold number and crude protein（CP） content. CTMR and LTMR silage had higher CP content, in vitro neutral detergent fiber digestibility（IVNDFD） and in vitro acid detergent fiber digestibility（IVADFD）, lower acid detergent fiber（ADF） content than MTMR silage. LP and EN decreased p H and increased dry matter（DM） recovery of TMR silages. LP＋EN improved the fermentation quality, nutritive characteristics and in vitro digestibility of TMR silages, showed by lower p H, ADF content, higher lactic acid content, in vitro dry matter digestibility（IVDMD） and IVNDFD. Therefore, It was suggested that TMR silage contained 7.5% RS on a DM basis and treated with LP＋EN can be as a useful feed for ruminant.

Effect of Certain Toxicants on Gonadotropin-Induced Ovarian Non-Esterified Cholesterol Depletion and Steroidogenic Enzyme Stimulation of the Common Carp Cyprinus carpio in vitro

Isolated ovarian tissues from the common carp, Cyprinus carpio were incubated in vitro to obtain a discrete effect of four common toxicants of industrial origin, namely phenol, sulfide, mercuric chloride and cadmium chloride, on gonadotropin-induced alteration of nonesterified and esterified cholesterol and steroidogenic enzymes, △5-3β-HSD and 17β-HSD activity. Stage II ovarian tissue containing 30-40% mature oocytes were shown to be most responsive to gonadotropins in depleting only nonesterified cholesterol moiety and stimulating the activity of both. Safe doses of above mentioned toxicants when added separately to stage II ovarian tissue with oLH (1 μg/incubation) gonadotropin-induced depletion of nonesterified cholesterol and gonadotropin-induced stimulation of the activity of both enzymes was significantly inhibited. Esterified cholesterol remained almost unaltered. Findings clearly indicate the impairment of gonadotropin induced fish ovarian steroidogenesis by the four toxicants separately.

First identification of isatin-β-thiosemicarbazones as novel inhibitors of New Delhi metallo-β-lactamase-1： Chemical synthesis, biological evaluation and molecular simulation

New Delhi metallo-b-lactmase-1（NDM-1） catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover novel agents to treat this superbug, an old drug methisazone was found to be a weak NDM-1 inhibitor, with an IC50 of 297.6 mmol/L. Based on this result, a series of isatin-β-thiosemicarbazones（IBTs）were synthesized and biologically evaluated as novel NDM-1 inhibitors. Nine of the IBT compounds showed IC50 values of 〈10 mmol/L, the best of which was 2.72 mmol/L. Comparative field analysis（Co MFA） contour maps were generated to depict the structural features and molecular docking was performed to understand the possible binding mode of these inhibitors. The present research hereby has provided valuable information for further discovery of NDM-1 inhibitors.