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Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The emergence of semi-quantum protocols reduces the conditions for the implementation of quantum signatures, so that users without quantum capabilities can communicate securely. As a kind of quantum signature, ring signature has been widely concerned in recent years because of its excellent characteristics such as unconditional anonymity. Combining the conception of semi-quantum with the characteristics of ring signature scheme, a semi-quantum ring signature protocol based on multi-particle GHZ state is proposed in this paper. It is achieved through the correlation between particles in GHZ state. In this protocol, only the trusted third-party arbitrator Trent has full quantum ability, called quantum party. The other users are classical parties with specific quantum capabilities, and there is no need for direct communication between the signer and the verifier, which makes the protocol has lower complexity and greatly reduces the dependence on quantum resources. In addition, the results of security analysis show that the proposed semi-quantum ring protocol scheme has the ability to reliably resist various attacks and has good security. [ABSTRACT FROM AUTHOR]

Prochiral pyrmetazole can be asymmetrically oxidized into (S)-omeprazole, a proton pump inhibitor that is used to treat gastroesophageal reflux, by an engineered cyclohexanone monooxygenase (CHMOAcineto-Mut) that has high stereoselectivity. CHMOAcineto-Mut is produced by heterologous expression in Escherichia coli, where it is expressed intracellularly. Thus, isolating this useful biocatalyst requires tedious cell disruption and subsequent purification, which hinders its use for industrial purposes. Here, we report the extracellular production of CHMOAcineto-Mut by a methylotrophic yeast, Pichia pastoris, for the first time. The recombinant CHMOAcineto-Mut expressed by P. pastoris showed a higher flavin occupation rate than that produced by E. coli, and this was accompanied by a 3.2-fold increase in catalytic efficiency. At a cell density of 150 g/L cell dry weight, we achieved a recombinant CHMOAcineto-Mut production rate of 1,700 U/L, representing approximately 85% of the total protein secreted into the fermentation broth. By directly employing the pH adjusted supernatant as a biocatalyst, we were able to almost completely transform 10 g/L of pyrmetazole into the corresponding (S)-sulfoxide, with > 99% enantiomeric excess. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Zhejiang University: Science B is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A low-cost rodent model of HIV infection and which presents high application value is an effective tool to investigate HIV infection and pathogenesis. However, development of such a small animal model has been hampered by the unsuitability of rodent cells for HIV-1 replication given that the retrovirus HIV-1 has high selectivity to its host cell. Our study used the mouse leukemia cell lines L615 and L1210 that were induced by murine leukemia virus and transfected with hCD4/CCR5 loaded-lentiviral vector. Lentiviral vectors containing the genes hCD4/CCR5 under the transcriptional control of cytomegalovirus promoter were designed. Transfection efficiencies of human CD4 and CCR5 in L615 and L1210 cells were analyzed by quantitative real-time polymerase chain reaction (RT-PCR) and Western blot assay. Results showed that hCD4 and CCR5 proteins were expressed on the cell surface, demonstrating that the L615 and L1210 cells were humanized and that they possess the characteristics necessary for HIV infection of human host cells. Moreover, the sensitivity of human CD4/CCR5 transgenic mouse cells to HIV infection was confirmed by RT-PCR and ELISA. Mouse leukemia cell lines that could express hCD4 and CCR5 were thus established to facilitate normal entry of HIV-1 so that a human CD4/CCR5 transgenic mice cell model can be used to investigate the transmission and pathogenesis of HIV/AIDS and potential antiviral drugs against this disease. [ABSTRACT FROM AUTHOR]