Evolution of quantum states via Weyl expansion in dissipative channel

Based on the Weyl expansion representation of Wigner operator and its invariant property under similar transformation,we derived the relationship between input state and output state after a unitary transformation including Wigner function and density operator.It is shown that they can be related by a transformation matrix corresponding to the unitary evolution.In addition,for any density operator going through a dissipative channel,the evolution formula of the Wigner function is also derived.As applications,we considered further the two-mode squeezed vacuum as inputs,and obtained the resulted Wigner function and density operator within normal ordering form.Our method is clear and concise,and can be easily extended to deal with other problems involved in quantum metrology,steering,and quantum information with continuous variable.

Efficient secretory expression of phospholipase D for the high-yield production of phosphatidylserine and phospholipid derivates from soybean lecithin

Phospholipase D(PLD)is an essential biocatalyst for the biological production of phosphatidylserine and phospholipid modification.However,the efficient heterologous expression of PLD is limited by its cell toxicity.In this study,a PLD was secretory expressed efficiently in Bacillus subtilis with an activity around 100 U/mL.A secretory expression system containing the signal peptide SPEstA and the dual-promoter PHpaII-SrfA was estab-lished,and the extracellular PLD activity further reached 119.22 U/mL through scale-up fermentation,191.30-fold higher than that of the control.Under optimum reaction conditions,a 61.61%conversion ratio and 21.07 g/L of phosphatidylserine production were achieved.Finally,the synthesis system of PL derivates was established,which could efficiently synthesis novel PL derivates.The results highlight that the secretory expression system constructed in this study provides a promising PLD producing strain in industrial application,and laid the foundation for the biosynthesis of phosphatidylserine and other PL derivates.As far as we know,this work re-ports the highest level of extracellular PLD expression to date and the enzymatic production of several PL der-ivates for the first time.

Transcriptomics reveals the effect of ammonia nitrogen concentration on Pseudomonas stutzeri F2 assimilation and the analysis of amtB function

The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In this paper,a transcriptomic approach was used to investigate the differences in gene expression at 500.0 mg/L(Amo 500)and 100.0 mg/L(Amo 100)ammonium concentrations to reveal the mechanism of ammonia nitrogen removal from water by Pseudomonas stutzeri F2.The transcriptome data showed 1015(459 up-regulated and 556 down-regulated)differentially expressed genes with functional gene annotation related to nitrogen source metabolism,glycolysis,tricarboxylic acid cycle,extracellular polysaccharide synthesis,energy conversion and transmembrane transport,revealing the metabolic process of ammonium nitrogen conversion to biological ni-trogen in P.stutzeri F2 through assimilation.To verify the effect of ammonium transporter protein(AmtB)of cell membrane on assimilation,a P.stutzeri F2-ΔamtB mutant strain was obtained by constructing a knockout plasmid(pK18mobsacB-ΔamtB),and it was found that the growth characteristics and ammonium removal rate of the mutant strain were significantly reduced at high ammonium concentration.The carbon source components and dissolved oxygen conditions were optimized after analyzing the transcriptome data,and the ammonium removal rate was increased from 41.23%to 94.92%with 500.0 mg/L ammonium concentration.The study of P.stutzeri F2 transcript level reveals the mechanism of ammonia nitrogen influence on microbial assimilation process and improvement strategy,which provides a new strategy for the treatment of ammonia nitrogen wastewater.

Mutation breeding of high 4-androstene-3,17-dione-producing Mycobacterium neoaurum ZADF-4 by atmospheric and room temperature plasma treatment

Steroid medication is used extensively in clinical applications and comprises a large and vital part of the pharmaceutical industry. However, the difficulty of separating 4-androstene-3,17-dione （AD） from 1,4-androstadiene- 3,17-dione （ADD） restricts the application of the microbial transformation of phytosterols in the industry. A novel at- mospheric and room temperature plasma （ARTP） treatment, which employs helium as the working gas, was used to generate Mycobacterium neoaurum mutants producing large amounts of AD. After treatment of cultures with ARTP, four mutants were selected using a novel screening method with a color assay. Among the mutants, M. neoaurum ZADF-4 was considered the best candidate for industrial application. When the fermentation medium contained 15 g/L phytosterols and was cultivated on a rotary shaker at 160 r/min at 30 ~C for 7 d, （6.28＋0.11） g/L of AD and （0.82＋0.05） g/L of ADD were produced by the ZADF-4 mutant, compared with （4.83＋0.13） g/L of AD and （2.34＋0.06） g/L of ADD by the original strain, Iv~. neoaururn ZAD. Compared with ZAD, the molar yield of AD increased from 48.3% to 60.3% in the ZADF-4 mutant. This result indicates that ZADF-4 may have potential for industrial production of AD.