| The use of antibiotics has taken various restrictive measures, but with its wide spread around the world, the microbial resistance is gradually increased. In recent years, appeared groups of microorganism resistance events and the superbug case, which shocking humans. So looking for a new antibacterial drugs is imminent. The gut microbes of sphaeroma because of its unique habitat, became an important source of new strains, antimicrobial drugs and leading compounds. In this paper used Misq sequencing platform and bioinformatics analysis to acquired the sphaeroma gut microbial diversity information from mangrove forest. On this basis, combined with the aculture method to isolated significantiy antibacterial activity strain from sphaeroma gut, identified the strain on the morphology and molecular biology, measured the physiological biochemical response and antimicrobial activity. the paper mainly includes two parts:1、16 s rDNA high-throughput sequencing results showed that three samples totally produced 794 OTU, and the adult, juvenile and larvae include 156,686,646 OTU respectively. The bioinformatics analysis results showed that there were detected 25 categories which dominant categories were Proteobacteria, Bacteroidetes and Fusobacterium, It accounted for 51.6%,55.1% and 51.7% respectively on total OTU. Proteobacteria was the predominant phylum of three samples, which respectively accounted for 51.7%,55.1% and 51.6% in larvae, juvenile and adult. Fusobacterium was the second predominant phylum of larvae which accounted for 37.8%. Bacteroidetes were the second predominant phylum of adult and juvenile which respectively accounted for 38.57% and 30.21%. Other phylum relative content was low in three samples. Found bacteria inhibitor activity of Bacillus and Erythrobacter; in three samples to the level of genus. Chao index were 190.50,697.16,66.12, Shannon index were 2.12,4.69,4.58, respectively in larvae, juvenile and adult. Larval microbial community structure was significant different from adult and juvenile on diversity index, dilution curve and PCA analysis. juvenile> adult> larvae on abundance and evenness, and larvae significantly lower than other two stage.2、Adnascent microbal bacteriostatic activity of screening and separation identification:There were 126 strains isolated from sphaeroma gut. Used staphylococcus aureus, e. coli, Pseudomonas aeruginosa and Aspergillus niger as the indicator. AGAR block inversion method was adopted to preliminary screening, filter paper method was adopted to after screen,and received 8 bacteriostatic activity strains. Used penicillin sodium, ampicillin sodium and bacteriostatic as antibiotics Standards to determination the antibiotic titer of 8 strains. The results showed that all strains had strong antibacterial activity on staphylococcus aureus, at least 6 strains had strong antibacterial activity on escherichia coli and pseudomonas aeruginosa. The Numbers for H2-1 and H2-8 strains had strong antibacterial activity on four kinds indicator bacteria, which relative potency was 0.698 U/ml and 0.650 U/ml,0.713 U/ml and 0.766 U/ml,4.593 U/ml and 3.672 U/ml to penicillin sodium, ampicillin sodium, and griseofulvin. Initially determined by physiological biochemical experiments and morphological identification of 8 kinds of bacteria, it included 2 kind of fungis and 6 kinds of bacteria. gram-positive bacteria H2-1 and H2-8 was the same kind of bacteria. Molecular biology method were adopted to identify two strains, the complete sequence was1418 bp. Both of the strain were bacillus subtilis.The sphaeroma gut microbes composition information was revealed for the first time, It provide the basis data to the development of Marine featuring medicinal microorganisms and natural products,There was the first time isolated bacteriostatic activity strains from mangrove parasitic animals gut. It had important theoretical and practical significance on simplify screening mangrove medical microbiology and excavating active substances. |
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