The degradation of plastics and the production of polyhydroxyalkanoates (PHA) / 生物工程学报

In recent years, the petroleum-based plastic pollution problem has been causing global attention. The idea of "degradation and up-cycling of plastics" was proposed for solving the environmental pollution caused by non-degradable plastics. Following this idea, plastics would be firstly degraded and then reconstructed. Polyhydroxyalkanoates (PHA) can be produced from the degraded plastic monomers as a choice to recycle among various plastics. PHA, a family of biopolyesters synthesized by many microbes, have attracted great interest in industrial, agricultural and medical sectors due to its biodegradability, biocompatibility, thermoplasticity and carbon neutrality. Moreover, the regulations on PHA monomer compositions, processing technology, and modification methods may further improve the material properties, making PHA a promising alternative to traditional plastics. Furthermore, the application of the "next-generation industrial biotechnology (NGIB)" utilizing extremophiles for PHA production is expected to enhance the PHA market competitiveness, promoting this environmentally friendly bio-based material to partially replace petroleum-based products, and achieve sustainable development with carbon-neutrality. This review summarizes the basic material properties, plastic upcycling via PHA biosynthesis, processing and modification methods of PHA, and biosynthesis of novel PHA.

Inhibitory activity of limonoids from Khaya grandifoliola C.DC (Meliaceae) against hepatitis C virus infection in vitro.

OBJECTIVE: A fraction from Khaya grandifoliola has recently been shown to inhibit hepatitis C virus (HCV) infection and three limonoids (17-epi-methyl-6-hydroxylangolensate, 7-deacetoxy-7-oxogedunin and 7-deacetoxy-7R-hydroxygedunin) were purified from this fraction. The present study aimed at assessing the inhibitory effect of these limonoids on HCV using cell-culture derived HCV (HCVcc) system. MATERIALS AND METHODS: Cytotoxic effects of the limonoids on Huh7.5 cells were assessed by MTT assay. Huh7.5 cells were transfected with RNA transcripts of the plasmid Jc1/GLuc2a, carrying a Gaussia luciferase reporter gene to rescue the HCVcc particles which were used to infect naïve cells in the presence or absence of the studied limonoids during 72 hr. Infection and replication rates were monitored by luciferase reporter assay and immunofluorescence assay (IFA) while cellular gene expression was analyzed by western blot, respectively. RESULTS: The limonoids inhibited HCV infection mostly by targeting entry and replication stage. Their inhibitory effect on entry step, comparable to that of anti-CD81 antibody, was related to the blocking of CD81 receptor. In the replication step, the limonoids decreased the expression of NS5B similar to danoprevir. These compounds also significantly decreased but up-regulated the expression of Class-III phosphatidylinositol 4-kinase alpha and 2',5'-oligoadenylate synthase-3, respectively. CONCLUSION: The present findings suggest that limonoids from K. grandifoliola are potential anti-HCV agents and may offer an advantage in the treatment of HCV infection.

Test and discussion on SPECT performance under the Chinese health industry standard WS523-2019 / 中华放射医学与防护杂志

Objective:To discuss the problems existing in the implementation of the Chinese health industry standard WS 523-2019 by testing SPECT device.Methods:Under the WS 523-2019 standards, a total of 10 SPECT devices were tested with regard to their SPECT reconstructed spatial resolution (SRSR), system planar sensitivity (SPS), system spatial resolution (SSR), whole body system spatial resolution (WSSR), intrinsic uniformity (IU), intrinsic count rate performance (ICR), intrinsic spatial resolution (ISR) and intrinsic spatial linearity(ISL).Result:Under the requirements of WS 523-2019 standards for qualified limits, there are 3 devices with ISL unqualified and the rest of the performances qualified. The new standards basically can meet the clinical requirements and reflected the overall performance of SPECT.Conclusions:The distance between the radiation source and the surface of the detector has great influence on the spatial resolution.In the measurement of ISL, there must be a lead grid separately in the x and y directions. The lead grids with the parallel slits shall be positioned on the detector with the center slit centered on the detector. It is suggested to add rotation center in the new standards.

Simultaneous vaccination of Chinese applicants for a United States immigrant visa.

BACKGROUND: Simultaneous vaccination is still uncommon in China, and many Chinese people are quite concerned about the adverse reactions because few data regarding the adverse reactions of simultaneous vaccination in Chinese people have been reported. The objective of this study was to evaluate the safety of simultaneous vaccination and the frequency of adverse reactions following simultaneous vaccinations in Chinese applicants for a United States immigrant visa. METHODS: We conducted a prospective observational study in 772 applicants receiving required vaccination in Guangdong International Travel Healthcare Center. The vaccines required for vaccination included diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP), adult formulation tetanus and diphtheria toxoids (Td), haemophilus influenzae type-b conjugate vaccine (Hib), oral polio vaccine (OPV), hepatitis B vaccine (HepB), combined measles mumps rubella vaccine (MMR), varicella vaccine (Var), and influenza vaccine (Inf), pneumococcal polysaccharide vaccine (PPV). Data on adverse reactions were collected by questionnaires. RESULTS: Seven hundred and seventy-two participants have received a total of 2533 doses of different vaccines, and 49.6% of the participants reported adverse reactions within 7 days following vaccination, with 39.8%(307/772) local reactions and 20.2%(156/772) systemic reactions. There were no allergic reactions. Only one vaccinee visited hospital seeking treatment due to fever, and recovered well. The most frequent local reaction was pain at the injection site (260/772, 33.7%), especially in the case of PPV vaccination, 61.2% (63/103) vaccinees who received PPV complained of pain at the site of injection, while the most frequent systemic reaction was fever (84/772, 10.9%). Pain and fever were all temporary reactions and resolved within 72h. Logistic regression analysis found that females experienced adverse reactions more frequently than males [(local reactions: female:male=41.7%(187/448):37%(120/324), p=0.04; systemic reactions: female:male=23%(103/448):16.4%(53/324), p=0.026)]; vaccinees given PPV developed local reactions more frequently than those receiving the other vaccines. The number of vaccines has no significant influence on adverse reactions. CONCLUSIONS: Simultaneous vaccination is feasible for Chinese applicants for a United States immigrant visa because the adverse reactions are mostly mild and temporary. Our data suggest that more Chinese people should be encouraged to receive simultaneous vaccination if the time is limited so as to reduce the risk of vaccine-preventable diseases.

Study of the mechanism of different regulation of Kir current in two expressions systems by PKC / 中国药理学通报

Aim To study the regulatory effects of PMA,a PKC activator,on Kir 2.3 channel function expressed in Xenopus oocytes and COS-7 cells,and PIP2 involvement in these regulations.Methods Kir 2.3 channel was expressed in Xenopus oocytes and COS-7 cell by RNA microinjection and DNA transfection using calcium phosphate precipitate,respectively.Two-electrode-voltage-clamp and whole-cell patch clamp were used to record the Kir 2.3 current in Xenopus oocytes and COS-7 cell.The PIP2 hydrolysis was detected by confocal microscopy.Results PMA significantly inhibited Kir 2.3 current in Xenopus oocytes.But PMA had no effect on the Kir 2.3 current expressed in COS-7 cell,in which activation of M1 receptor,however,induced a significant inhibition of Kir 2.3 current.It was reported recently that PMA could trigger the PIP2 hydrolysis in membrane of oocytes.Thus PKC inhibition of Kir 2.3 current seen in oocytes could be the result of PIP2 hydrolysis.Following the same line,the inability of PKC inhibition of Kir 2.3 current seen in COS-7 cells would suggest PKC could not induce PIP2 hydrolysis in these cells. This hypothesis was tested by monitoring the PIP2 level in COS-7 cell membrane by confocal microscopy.Dynamic changes in membrane PIP2 level were imaged using GFP fluorescence signal that had been tagged to the PLC?1PH domain known to be able to bind PIP2 specifically. There was no significant change of PIP2 level on COS-7 cell membrane after longtime treatment of PMA,whereas again,the activation of M1 receptor by ACh induced a significant change in the PIP2 level.These results were in perfect agreement with the electrophysiological results.Conclusions PMA,through activation of PKC,inhibited Kir 2.3 current expressed in Xenopus oocytes but not in COS-7 cells.Similarly PMA induced significant reduction in membrane PIP2 level in Xenopus oocytes but not in COS-7 cells. PIP2 hydrolysis plays an important role in PKC-induced inhibition of the Kir channel currents.