Characteristics of African swine fever virus and difficulties in vaccine development / 生物工程学报

African swine fever (ASF) is a devastating disease of pigs caused by African swine fever virus (ASFV), which is considered to be the No. 1 killer to the global pig industry. Highly virulent strains are usually responsible for the peracute and acute forms that provoke high mortality rates that may reach 100%. Since ASF was first introduced in August 2018 into China, 137 outbreaks in domestic and wild pigs had been reported from 32 provinces by June 06, 2019, causing severe socioeconomic consequences. Efforts to develop an ASFV vaccine began in the 1960s, but all failed, the major reason is the lack of in-depth research on the biological characteristics of ASFV. It will be a great challenge for China to control the spread of current ASF, develop safe and effective vaccines. In this review, we outline the biological characteristics of ASFV, including its morphology and basic structure, transmission routes, pathogenicity, genome and proteins, entry mechanism, immune escape, and analyzed the difficulties in vaccine development. We hope to provide basic information for the control of current ASF and understanding of etiology in China.

Structural dynamics of the yeast Shwachman-Diamond syndrome protein (Sdo1) on the ribosome and its implication in the 60S subunit maturation

The human Shwachman-Diamond syndrome (SDS) is an autosomal recessive disease caused by mutations in a highly conserved ribosome assembly factor SBDS. The functional role of SBDS is to cooperate with another assembly factor, elongation factor 1-like (Efl1), to promote the release of eukaryotic initiation factor 6 (eIF6) from the late-stage cytoplasmic 60S precursors. In the present work, we characterized, both biochemically and structurally, the interaction between the 60S subunit and SBDS protein (Sdo1p) from yeast. Our data show that Sdo1p interacts tightly with the mature 60S subunit in vitro through its domain I and II, and is capable of bridging two 60S subunits to form a stable 2:2 dimer. Structural analysis indicates that Sdo1p bind to the ribosomal P-site, in the proximity of uL16 and uL5, and with direct contact to H69 and H38. The dynamic nature of Sdo1p on the 60S subunit, together with its strategic binding position, suggests a surveillance role of Sdo1p in monitoring the conformational maturation of the ribosomal P-site. Altogether, our data support a conformational signal-relay cascade during late-stage 60S maturation, involving uL16, Sdo1p, and Efl1p, which interrogates the functional P-site to control the departure of the anti-association factor eIF6.

Simultaneous Determination of Schaftoside, Isoschaftoside, Deoxyelephantopin and 4, 5-Dicaffeoylquinic Acid in Shennongcha Granules by HPLC / 中国药师

Objective:To establish an HPLC method for determining four constituents ( schaftoside, isoschaftoside, deoxyelephan-topin and 4,5-dicaffeoylquinic acid) in Shennongcha granules. Methods:An HPLC method was performed on a Hypersil C18 column (200 mm × 4. 6 mm,5 μm) with the mobile phase of acetonitrile as the phase A and 0. 025 mol·L-1 phosphoric acid solution as the phase B with gradient elution. The flow rate was 1. 3 ml·min-1 . The detection wavelength was set at 270 nm for schaftoside and isos-chaftoside, 208 nm for deoxyelephantopin and 327 nm for 4, 5-dicaffeoylquinic acid. The column temperature was room temperature. Results:The calibration curve was linear over the concentration range of 5. 850-117. 000 μg·ml-1 for schaftoside, 4. 650-93. 000 μg ·ml-1 for isoschaftoside, 4. 160-83. 200 μg · ml-1 for deoxyelephantopin and 5. 470-109. 400 μg · ml-1 for 4, 5-dicaffeoylquinic acid. The correlation coefficient of all curves was more than 0.999. The average recoverywas 97.70% (RSD=1.40%), 96.87%(RSD=1.13%), 97.53%(RSD =1.69%) and 99.29%(RSD =1.01%) (n =6) , respectively. Conclusion: The developed HPLC method is simple,accurate,and can be used in the content determination of Shennongcha granules.

Structural insights into the assembly of the 30S ribosomal subunit in vivo: functional role of S5 and location of the 17S rRNA precursor sequence

The in vivo assembly of ribosomal subunits is a highly complex process, with a tight coordination between protein assembly and rRNA maturation events, such as folding and processing of rRNA precursors, as well as modifications of selected bases. In the cell, a large number of factors are required to ensure the efficiency and fidelity of subunit production. Here we characterize the immature 30S subunits accumulated in a factor-null Escherichia coli strain (∆rsgA∆rbfA). The immature 30S subunits isolated with varying salt concentrations in the buffer system show interesting differences on both protein composition and structure. Specifically, intermediates derived under the two contrasting salt conditions (high and low) likely reflect two distinctive assembly stages, the relatively early and late stages of the 3' domain assembly, respectively. Detailed structural analysis demonstrates a mechanistic coupling between the maturation of the 5' end of the 17S rRNA and the assembly of the 30S head domain, and attributes a unique role of S5 in coordinating these two events. Furthermore, our structural results likely reveal the location of the unprocessed terminal sequences of the 17S rRNA, and suggest that the maturation events of the 17S rRNA could be employed as quality control mechanisms on subunit production and protein translation.

Determination of Residual Solvents in Azithromycin Raw Material by GC / 中国药房

OBJECTIVE:To determine the contents of the residual solvents including dichloromethane,acetone and ethanol in azithromycin raw material by GC.METHODS:A glass column was used as chromatographic column.The temperature of sample injection was 140℃and column temperature was 160℃.The carrier gas was nitrogen.The column inlet pressure was 30Psi.The detection was performed using hydrogen flame ionization detector.RESULTS:The detection concentrations of dichloromethane,acetone and ethanol were 0.02%～0.1%(r=0.9 995),0.05%～0.25%(r=0.9 994)and 0.02%～0.1%(r=0.9 994),respectively.The average recovery were 99.1%(RSD=1.4%),100.1%(RSD=1.1%)and 99.5%(RSD=1.3%),respectively.All of the three batches of samples were up to the standard with regard to the residual volume of organic solvent residues in azithromycin raw material.CONCLUSION:The method is proved to be accurate,sensitive and reliable,and suitable for the detection of organic solvent residues in azithromycin.

Preparation and Quality Control of Piyanjing Cream / 中国药房

OBJECTIVE : To prepare Piyanjing cream and to establish a quality control method for it. METHODS : Chemical reactions were performed to identify Piyanjing cream qualitatively. The content of main agent, clobetasol propionate was determined by HPLC. RESULTS: Chemical reactions were positive .The clobetasol propionate linearity was between 4.06～97.49?g/ml,and the average recovery was 98.67%(RSD=0.82%,n=9),the average content of clobetasol propionate was 0.492mg/g.CONCLUSION : The prescription and the preparation technique are reasonable,the cream is stable in quality,the quality control is simple ,accurate and practicable.