植物内生菌及其代谢物在生物农药创制中的应用

基于植物内生菌,包括内生真菌、内生细菌、内生放线菌在生物农药创制中的重要性和实践意义,综述了植物内生菌的多样性及其在植物不同部位中的分布,不同内生真菌、细菌和放线菌及其代谢物在抑菌杀虫中的生物活性,并就植物内生菌在生物农药创制中的应用作一展望,提出今后研究重点和方向。

植物内生菌及其代谢产物在生物农药创制中的应用

基于植物内生菌在生物农药创制中的重要性和实践意义,综述植物内生菌的多样性及其在植物不同部位中的分布,不同内生真菌、细菌和放线菌及其代谢物在抑菌杀虫中的生物活性.并就植物内生菌在生物农药创制中的应用展望,提出今后研究的重点和方向.

桦褐孔菌的生物活性及其应用研究

总结桦褐孔菌的多种生物活性,分析从桦褐孔菌中分离的代谢物在药物评价方面的最新进展,并针对桦褐孔菌的实际应用和其活性代谢产物的工业化生产现状进行总结分析,重点阐述桦褐孔菌在抗癌及抗病毒,尤其是在当前新型冠状病毒(SARS-CoV-2)方面的潜力,凸显桦褐孔菌巨大的药理价值和保健作用,为桦褐孔菌的进一步应用研究提供参考。

LC-MS/MS法测定人血浆中氯吡格雷活性代谢物衍生物浓度的不确定度评定

目的:评定液相色谱串联质谱(LC-MS/MS)法测定人血浆中氯吡格雷活性代谢物衍生物(CAMD)浓度的不确定度。方法:对LC-MS/MS法测定人血浆中CAMD浓度的整个过程进行分析,对测定过程中的测量重复性、称量、工作液配制、生物样品制备、回收率、仪器允差和标准曲线拟合等因素引起的不确定度分别进行了评定,最后计算合成不确定度并进行扩展。结果:血浆CAMD低(0.107ng/ml)、中(4.467ng/ml)、高(155.667ng/ml)质量浓度质控的扩展不确定度分别为0.010 2、0.188、6.413ng/ml(k=2,P=95%)。结论:LC-MS/MS法测定人血浆中CAMD的不确定度在低浓度时主要由曲线拟合引入,在中浓度和高浓度时主要由生物样品配制、萃取过程、对照品配制和仪器允差引入。

Biodiversity and biotechnological potential of mangrove-associated fungi

This review describes the present hot research areas of mangrove-associated fungi, including its biodiversity, ecological roles, novel metabolites productions and biotechnological potential. Mangrove-associated fungi were divided into saprophytic, parasitic and true symbiotic fungi based on its ecological roles. Saprophytic fungi are fundamental to decomposition and energy flow of mangrove, additionally, their potential toxicity also exists. Pathogenic fungi have significant effects on mangrove survival, growth, and fitness. Endophytic fungi, the most prolific source of diverse bioactive compounds found among that of mangrove-associated fungi, are found in most species of mangroves. Although a significant number of reports focused on the antimicrobial, insecticidal and other bioactive metabolites as well as many novel enzymes isolatcd from mangrove-associated fungi, and many of those metabolites from endophytic fungi are suspected to be of significant to mangrove, only few studies have provided convincing evidence for symbiotic producers in mangrove. Hence, this paper discusses the present progress of molecular methods used to correlate the ecological roles of endophytic fungi with their bioactive metabolites;, meanwhile, the potential of using metabolic engineering and post-genomic approaches to isolate more novel enzymes and bioactive compounds and to make their possible commercial application was also discussed.

Construction of a Metagenomic DNA Library of Sponge Symbionts and Screening of Antibacterial Metabolites

To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DNA and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.

Secondary Metabolites of a Deep Sea Derived Fungus Aspergillus versicolor CXCTD-06-6a and Their Bioactivity

In order to obtain novel secondary metabolites, a deep sea inhabiting fungus Aspergillus versicolor CXCTD-06-6a was investigated. One new diketopiperazine brevianamide W(1a), as well as five known diketopiperazine alkaloids, diketopiperazine V(1b), brevianamide Q(2), brevianamide R(3), brevianamide K(4), and brevianamide E(5), were isolated from the Et OAc extract of the fermentation broth. Their structures were elucidated by spectroscopy techniques(NMR, MS). The six compounds exhibited moderate radical scavenging activity against DPPH with clearance ratio of 55.0%(1a and 1b), 53.7%(2), 46.2%(3), 61.4%(4) and 19.3%(5) at a concentration of 13.9 μmol L-1, respectively; while the positive control ascorbic acid showed a ratio of 70.3% at the concentration of 28.4 μmol L-1.

Recent Researches of Bioactive Metabolites in Marine Organisms-associated Microorganisms

Recent researches have shown that some compounds isolated from marine organisms have striking structural similarities with the metabolites from known microorganisms. It is inferred from the researches that the symbiotic or associated marine microorganisms may be the true sources of those compounds or at least involved in the biosynthesizing process. This view has been further evidenced by the researches for many sponges and sponge-associated microorganisms. Importantly, growing evidence has highlighted that the symbiotic or associated marine microorganisms live in the microenvironment within the hosts, and they also produce secondary metabolites which are new and original in structure and unique in activity. All these suggest that the microorganisms associated with marine organisms are the sources with very high potential to be new natural bioactive agents. This article reviews briefly the research advances in the study of new bioactive metabolites from marine organisms-associated microorganisms since 2000.

Antimicrobial Activity of Ulva reticulata and Its Endophytes

Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy （GC-MS） revealed the existence of phenol, 3, 5-bis （1, 1-dimethylethyl） in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas smtzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.

Natural products from Bacillus subtilis with antimicrobial properties

Bacillus subtilis produces many chemlcally-dwerse seconaary metaDolltes or interest to chemists ano biologlsts. Based on this, this review gives a detailed overview of the natural components produced by B. subtilis including cyclic lipopeptides, polypeptides, proteins （enzymes）, and non-peptide products. Their structures, bioactive ac- tivities and the relevant variants as novel lead structures for drug discovery are also described. The challenging effects of fermentation metabolites, isolation and purification, as well as the overproduction of bioactive com- pounds from B. subtilis by metabolic engineering, ＇~ere also highlighted. Systematically exploring biosynthetic routes and the functions of secondary metabolites from 13. subtilis may not only be beneficial in improving yields of the products, but also in helping them to be used in food industry and public medical service on a large-scale.

Symbionts, a promising source of bioactive natural products

Symbionts are microorganisms residing in multicellular hosts(e.g., plants and animals), and they have been witnessed to be a rich source of diverse functional molecules. This review describes structures and biological activities of symbiont-derived secondary metabolites commonly referred to as "natural products", and highlights that symbiotic microbes represent an underexplored reservoir of natural products with unique scaffolds and promising significance in managing human healthcare and agricultural production.