Transcriptomic analysis of Andrias davidianus meat and experimental validation for exploring its bioactive components as functional foods

Andrias davidianus(Chinese giant salamander,CGS)is the largest and oldest extant amphibian species in the world and is a source of prospective functional food in China.However,the progress of functional peptides mining was slow due to lack of reference genome and protein sequence data.In this study,we illustrated full-length transcriptome sequencing to interpret the proteome of CGS meat and obtain 10703 coding DNA sequences.By functional annotation and amino acid composition analysis,we have discovered various genes related to signal transduction,and 16 genes related to longevity.We have also found vast variety of functional peptides through protein coding sequence(CDS)analysis by comparing the data obtained with the functional peptide database.Val-Pro-Ile predicted by the CDS analysis was released from the CGS meat through enzymatic hydrolysis,suggesting that our approach is reliable.This study suggested that transcriptomic analysis can be used as a reference to guide polypeptide mining in CGS meat,thereby providing a powerful mining strategy for the bioresources with unknown genomic and proteomic sequences.

Exogenously applied methyl jasmonate increased the resistance of postharvest pear fruit to blue mold

Methyl jasmonate(MeJA)is a plant-signalling molecule that plays significant roles in stress reactions and defence responses.The goal of this study was to characterize the effects of exogenous MeJA application on the resistance of postharvest pear fruit to blue mould rot caused by Penicillium expansum and investigate the mechanism underlying the observed effects of MeJA application.MeJA treatment effectively reduced the lesion diameter of blue mould rot in pear fruit.Furthermore,MeJA significantly enhanced the activities of antioxidant and defence-related enzymes,such as polyphenol oxidase(PPO),superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),β-1,3 glucanase(GLU)and chitinase(CHI);total phenol content also increased,and membrane lipid peroxidation decreased.MeJA treatment promoted the expression of PpPPO,Cu-ZnSOD,PpPOD,PpCAT,PpCHI and PpGLU.Overall,this experiment suggested that MeJA-induced pear fruit resistance against blue mould rot may be related to the enhanced activities of defence enzymes and gene expression.

Feasible and reliable quantification of mRNA in Arabidopsis thaliana using optical thin-film biosensor chips

mRNA quantification is very important in molecular biological researches. Traditional spectrophotometric method cannot distinguish DNA, rRNA and tRNA species from mRNA. Northern blot can be used for mRNA quantification but is known to be time consuming. To rapidly detect mRNA levels, we developed an optical thin-film biosensor chip based method, to quantify mRNA in samples. After total RNA was extracted, the mRNA with poly（A） tails was reverse transcribed with oligo（dT）20 primers and dNTPs mixed with digoxigenin（DIG）-11-dUTE The transcribed first strand cDNA was hybridized with oligo（dA）20 nucleotide probes spotted on optical thin-film biosensor chips. Excess first strand cDNA, single-strand RNA, and mis-matched DNA/DNA hybrids were removed by washing. The perfect-matched DNA/DNA hybrid was detected with anti-DIG-AP （alkaline phosphatase） conjugate and then incubated with NBT/BCIP substrate for color development. The range of the color is from purplish red to blue, according to the cDNA mass deposited on chip sur- face. Detection of mRNA levels from Arabidopsis samples proved that this method is feasible for mRNA quantification, and has great potential for application in mRNA quantification in various organisms.

天然活性多肽的发掘策略和生产技术

活性多肽可以参与生命机体的多种生理活动,对促进人体健康发挥着重要的作用,如降血压、降血糖、降血脂和抗癌等,其创制技术也逐渐成为重要的研究和应用转化方向。本综述旨在总结天然活性多肽的发掘策略和生产技术的研究进展。目前,天然活性多肽的发掘与生产技术主要包括自上而下和自下而上两种方法,其中自上而下方法在多肽发掘方面主要为直接提取鉴定法,在生产技术方面主要包括直接提取法、酶解法和微生物发酵法;自下而上方法在多肽发掘方面包括天然活性多肽改造和数据库发掘方法,在生产技术方面主要方法包括化学合成法、酶合成法、基因重组表达法和无细胞合成法。自上而下的天然多肽制备与功能验证方法存在步骤烦琐、耗费时间长、功能不确定性大、实验与生产成本高以及质量控制难度大等问题;而自下而上的活性多肽合成与功能验证方法适合多肽药物的开发,而难以用于功能食品。随着测序和质谱技术的发展,人们更容易从分子水平获取物种蛋白组信息。以此蛋白组信息为根据,将自上而下和自下而上两种方法结合,可以克服单独使用这两种方法存在的问题,从而为快速开发和生产天然活性多肽提供新的策略。

Discovering unusual structures from exception using big data and machine learning techniques

Recently, machine learning(ML) has become a widely used technique in materials science study. Most work focuses on predicting the rule and overall trend by building a machine learning model. However,new insights are often learnt from exceptions against the overall trend. In this work, we demonstrate that how unusual structures are discovered from exceptions when machine learning is used to get the relationship between atomic and electronic structures based on big data from high-throughput calculation database. For example, after training an ML model for the relationship between atomic and electronic structures of crystals, we find AgO2 F, an unusual structure with both Ag3+and O22à, from structures whose band gap deviates much from the prediction made by our model. A further investigation on this structure might shed light into the research on anionic redox in transition metal oxides of Li-ion batteries.

Synchronous nanoscale topographic and chemical mapping by differential-confocal controlled Raman microscopy

Confocal Raman microscopy is currently used for label-free optical sensing and imaging within the biological,engineering,and physical sciences as well as in industry.However,currently these methods have limitations,including their low spatial resolution and poor focus stability,that restrict the breadth of new applications.This paper now introduces differential-confocal controlled Raman microscopy as a technique that fuses differential confocal microscopy and Raman spectroscopy,enabling the point-to-point collection of three-dimensional nanoscale topographic information with the simultaneous reconstruction of corresponding chemical information.The microscope collects the scattered Raman light together with the Rayleigh light,both as Rayleigh scattered and reflected light(these are normally filtered out in conventional confocal Raman systems).Inherent in the design of the instrument is a significant improvement in the axial focusing resolution of topographical features in the image(to^1 nm),which,when coupled with super-resolution image restoration,gives a lateral resolution of 220 nm.By using differential confocal imaging for controlling the Raman imaging,the system presents a significant enhancement of the focusing and measurement accuracy,precision,and stability(with an antidrift capability),mitigating against both thermal and vibrational artefacts.We also demonstrate an improved scan speed,arising as a consequence of the nonaxial scanning mode.