Research Progress of Pectinase

Pectinase is a group of enzymes that can decompose complex pectin into small molecules such as galacturonic acid. It is mainly produced by microorganisms by liquid and solid fermentation and immobilized cell method. Its representative strain is Aspergillus niger,and yeast and actinomycete are also high-yield strains for screening pectinase. Pectinase can be used in many fields of life and production,such as clarification of fruit juice and wine,pulping of paper making industry,degumming of textile,extracting of traditional Chinese medicine components,animal feed and other industries,which is economic,green,and efficient and pollution-free. Moreover,pectinase is one of the four major enzymes in the world,and its practical application has very important significance,and the prospect of pectinase application is also important.

Advances in Studies on Extraction Methods and Physiological Activities of Jujube Flavonoids

Jujube is rich in nutrients and functional active ingredients. For example,jujube flavonoids have significant anti-oxidation,anticancer,antibacterial and anti-inflammatory functions. This paper elaborated the advances in the studies about the extraction methods,purification methods,antioxidant properties,stability and antibacterial effects of jujube flavonoids,in order to provide a certain reference for the study of jujube flavonoids.

Effects of Different Storage Conditions on Physiological and Biochemical Characteristics of Polygala tenuifolia Willd. Seeds

[Objectives] Taking Polygala tenuifolia Willd. seeds as experimental material, the changes of physiological and biochemical characteristics of seeds under different storage temperatures and seed moisture contents were studied. [Methods] The seeds of P. tenuifolia Willd. with moisture contents of 3%, 5% and 15% were stored at-10 ℃, 0 ℃, 20 ℃ and 36 ℃, respectively, and the storage time was one year. The physiological and biochemical characteristics of the seeds, such as conductivity, SOD activity, POD activity, and soluble sugar content were studied.[Results] After one-year storage, as the storage temperature and seed moisture content increased, the relative conductivity, MDA content and soluble sugar content of P. tenuifolia Willd. seeds increased, while the SOD activity, POD activity, and protein content declined. This phenomenon was most obvious in the P. tenuifolia Willd. seeds with moisture content of 15%. [Conclusions] This study will provide reference for seed storage of medicinal plants.

Content Determination of Trace Elements in Several Vegetables by Atomic Absorption Spectrophotometry

The contents of Mn,Zn and Cu,three essential trace elements for human body,in Laminaria japonica,Auricularia auricula( L. ex Hook.) Underwood,Porphyra,Cucurbita pepo L.,Spinacia oleracea L. and Coriandrum sativum were determined by atomic absorption spectrophotometry. Vegetable samples were processed by wet digestion. The results showed that among the six vegetables,Mn had the highest content in A. auricula( 26. 60 μg/g) and the lowest content in C. pepo( 1. 22 μg/g); Zn had the highest content in Porphyra( 38. 07 μg/g)and the lowest content in L. japonica( 10. 32 μg/g); and Cu had the highest content in Porphyra( 10. 35 μg/g) and the lowest content in S. oleracea( 0. 61 μg/g). Each determination was repeated five times. The value of RSD was less than 10%,indicating high accuracy.

Peptide targeting the interaction of S protein cysteine-rich domain with Ezrin restricts pan-coronavirus infection

Dear Editor,To date,seven human coronaviruses(HCoVs)have been identified,among which the highly pathogenic severe acute respiratory syndrome-associated coronavirus(SARS-CoV),Middle East respiratory syndrome coronavirus(MERS-CoV),and severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)have caused public health disasters worldwide.

Palmitoylation of SARS-CoV-2 S protein is essential for viral infectivity

Dear Editor,Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the causative agent of the unprecedented coronavirus disease 2019(COVID-19).SARS-CoV-2 entry into host cells is mediated by the viral transmembrane spike(S)glycoprotein that forms homotrimers protruding from the viral surface.

Sensitivity of Estimated Total Canopy SIF Emission to Remotely Sensed LAI and BRDF Products

Remote sensing of solar-induced chlorophyll fluorescence(SIF)provides new possibilities to estimate terrestrial gross primary production(GPP).To mitigate the angular and canopy structural effects on original SIF observed by sensors(SIF_(obs)),it is recommended to derive total canopy SIF _(emission)(SIF_(total))of leaves within a canopy using canopy interception(i0)and reflectance of vegetation(R_(V)).However,the effects of the uncertainties in i_(0) and R_(V) on the estimation of SIFtotal have not been well understood.Here,we evaluated such effects on the estimation of GPP using the Soil-Canopy-Observation of Photosynthesis and the Energy balance(SCOPE)model.The SCOPE simulations showed that the R^(2) between GPP and SIF_(total) was clearly higher than that between GPP and SIFobs and the differences in R^(2)(ΔR^(2))tend to decrease with the increasing levels of uncertainties in i_(0) and RV.The resultantΔR^(2) decreased to zero when the uncertainty level in i0 and RV was~30%for red band SIF(RSIF,683 nm)and~20%for far-red band SIF(FRSIF,740 nm).In addition,as compared to the TROPOspheric Monitoring Instrument(TROPOMI)SIFobs at both red and far-red bands,SIF_(total) derived using any combination of i_(0)(from MCD15,VNP15,and CGLS LAI products)and RV(from MCD34,MCD19,and VNP43 BRDF products)showed comparable improvements in estimating GPP.With this study,we suggest a way to advance our understanding in the estimation of a more physiological relevant SIF datasets(SIF_(total))using current satellite products.