Diversity,Antibacterial Activity And Secondary Metabolites Of Actinomycetes From Mangroves In Guangxi

Objective:To study the actinomycetes diversity and antibacterial activity screening of mangrove roots,stems,leaves,seawater,sediments and the rhizosphere soil of mangrove plants in Maowei Sea and Beilun River estuary in Guangxi Qinzhou and Beihai,and to screen for antibacterial active compounds Carry out separation,purification and identification to provide valuable resources for mining new antibacterial drugs.Methods:Collect rhizosphere soil samples of mangrove plants in Maowei Sea and Beilun River Estuary,using 10 different separation media,and isolate and purify strains by dilution coating method;roots,stems,leaves,sea water,sediments of mangrove plants in Qinzhou and Beihai Through PCR amplification and 16 S r RNA gene sequencing and database comparison,a phylogenetic tree was constructed for homologous species analysis,and the diversity of actinomycetes was studied;10 drug-resistant strains were used as standard strains,and cross-stitching was used Screening for antibacterial activity,using different culture media to optimize the fermentation conditions for actinomycetes with antibacterial activity;through the extraction of crudeextracts,one of the actinomyces is selected using silica gel column chromatography,HPLC,TLC and other comprehensive methods Separation and purification of compounds,using NMR and other techniques to analyze the structure of monomer compounds.Results:A total of 48 strains of actinomycetes were isolated from Guangxi Beihai and Qinzhou Mangrove Nature Reserves.They are distributed in 7 orders,12 families and 19 genera.The Micrococcaceae family includes Micrococcus,Arthrobacter,Paenarthrobacter and Curtobacterium are 4genera;Nocardiaceae includes Rhodococcus and Gordonia are 2 genera;My cobacteriaceae includes Mycobacterium and Mycolicibacterium are 2 gener a;Nocardioidaceae includes Nocardioides and Marmoricola are 2 genera;Micromonosporaceae includes Plantactinospora and Couchioplanes caeruleussubsp.are 2 genera;Streptomycetaceae includes one genera of Streptomyces;Microbacteriaceae includes one genera of Microbacterium;Dermacoccaceae includes one genera of Demequina;Intrasporangiaceae includes one generaof Janibacter;Dermabacteraceae includes one genera of Brachybacterium;Nakamurellaceae includes one genera of Q u a d r i s p h a e r a;K i n e o s p o r r i a c e a e i n clu d es o n e g e n e r a o f Kineococcus;among them Streptomyces and Arthrobacter are the dominan bacteria Genus.The resultsof 48 actinomycetes screened forantibacterial activity showed that 6 strains had antibacterial activity,with a totalpositive rate of 12.5%,of which 3 strains of actinomycetes B535,B752,and B3415 had strong broad-spectrum antibacterial activity,with a positive rate6.25%,By optimizing the fermentation condition of these three strains in different mediumthe appropriate culture conditions were determines,and the secondary metabolites of the B535 strain were separated and purified to obtain six monomer compounds,and the analysis of two compounds was carried out with the NMR spectrum.Conclusion:Guangxi mangrove actinomycetes are rich in resources,and their antibacterial activity secondary metabolites provide a material basis for further exploration of new compound.