| According to reports,multi-drug resistant bacteria cause about 700 thousand deaths and 230 thousand newborn babies died worldwide each year,By the year of 2050,the toll number of death may be more than 10 million.The increasing spread of drug-resistant pathogens has become a problem that can not be ignored.However,the discovery of new antibiotics is slowing down.Mining of new antibiotics is becoming more and more important.In this paper,through the enrichment of the samples from the sea shore of Weihai,118 strains of marine antagonistic bacteria and 4 strains of predatory bacteria are isolated.Two strains of selected marine antagonistic bacteria are conducted a preliminary study,including analysis of phenotypic characteristics,physiological characteristics,exploring of antibacterial spectrum,preliminary optimization of fermentation conditions,analysis of genomic information and prediction of antagonistic genes.Strain BXN2401 showed 99.78%similarity to its closest relative,Desemzia incerta DSM 20581T and strain BXO402 showed 99.35%similarity to its closest relative,Ruegeria mobilis DSM 23403T.Through the exploring of antibacterial spectrum,it was found that the strain BXN2401 had a wide range of antibacterial activity against the 12 indicators,such as Vibrio aestuarianus ATCC 35048T,Vibrio diazotrophicus ATCC 33466T,Vibrio gazogenes ATCC 29988T,Vibrio parahaemolyticus ATCC 17802T,Vibrio natriegens ATCC 14048T,Pseudomonas aeruginosa ATCC 27853,Staphylococcus aureus ATCC 25923,Staphylococcus aureus ATCC 29213,Acinetobacter baumannii ATCC 19606T,Arcobacter achromus NP18T.Strain BXO402 had antibacterial activity against Klebsiella pneumoniae ATCC 700603,Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923.Through the preliminary optimization of fermentation conditions,suitable medium of strain BXO402 can't be selected for fermentation of antibiotic substances,and the suitable fermentation medium of antibiotic substances of strain BXO402 was selected which contains 2%(w/v)beef extract,0.5%(w/v)yeast extract and aged seawater,pH 7.0-7.5.Good antibacterial effect was obtained from 12 h fermentation with 1%inoculum.Through analysis of genomic information and prediction of antagonistic genes,it is found that strain BXN2401 has 6 genes related to the production of antibiotics,including 2 genes related to the production of penicillin and cephalosporins,3 genes related to the production of streptomycin,a gene related to the production of neomycin.Strain BXO402 has 17 genes related to the production of antibotics,including 3 genes associated with the production of penicillin and cephalosporin,9 genes associated with the production of streptomycin,a gene associated with the production of cyclosporine and neomycin,4 genes associated with the production of new antibiotics.In this paper,12 strains of common pathogenic bacteria and two strains of potential pathogens identified by our laboratory were selected as the prey.The results showed that the 4 strains had the similar predation fingerprint against the 14 strains.And it is found that they prey on both Gram negative bacteria and gram positive bacteria.In order to develop the database of marine microbial resources,3 strains isolated from different samples are identified by polyphasic taxonomy.Strain FA150T was isolated from the coastal area of Weihai,China.Cells are Gram-stain-negative,facultative anaerobic,oxidase positive,catalase negative,nitrate was reduced to nitrite.Tween 20 was hydrolysed but Tween 40,60,80,starch,sodium alginate and CM-cellulose were not.The predominant fatty acids were Summed Feature 3(C16:1?7c and/or iso-C15:0 2-OH)(42.56%),C18:1 ?7c(12.51%),C16:0(10.43%),C12:0(9.75%)and C14:0(9.11%).The sole methyl naphthoquinone was MK-6 and the major polar lipids were phosphatidylethanolamine(PE)and phosphatidylglycerol(PG).The DNA G+C content of the type strain was 31.34 mol%(HPLC).Based on the distinct position and the combination of phenotypic and physiological characteristics,strain FA150T is considered to represent a novel species of the genus Arcobacter,for which the name Arcobacter achromus sp.nov.is proposed.The type strain is FA150T(= KCTC 42593T= MCCC 1H00108T).Strain NP18T was isolated from the mariculture pond of Rongcheng of Weihai,China.Cells were Gram-stain-negative,facultative anaerobic,oxidase and catalase positive,nitrate was reduced to nitrite.Tween 20 was hydrolysed but Tween 40,60,80,starch,sodium alginate and CM-cellulose were not.The predominant fatty acids were Summed Feature 3(C16:1 ?7c and/or iso-C15:0 2-OH)(44.01%),C16:0(19,59%),C14:0(11.47%),C18:1 ?7c(9.85%)and C12:0(8.57%).The sole methyl naphthoquinone was MK-6 and the major polar lipids were phosphatidylethanolamine(PE),phosphatidylglycerol(PG)and diphosphatidylglycerol(DPG).The DNA G+C content of the type strain was 29.54 mol%(HPLC).Based on the distinct position and the combination of phenotypic and physiological characteristics,strain NP18T is considered to represent a novel species of the genus Arcobacter,for which the name Arcobacter achromus sp.nov.is proposed.The type strain is NP18-T(= KCTC 42592-T= MCCC 1H00109T).Strain SS2-24T was isolated mariculture pond of Weihai,China.Cells were Gram-stain-negative,facultative anaerobic,oxidase positive,catalase negative,nitrate was not reduced to nitrite.Tween 20,40,60 and 80 were hydrolysed but starch,sodium alginate and CM-cellulose were not.The predominant fatty acids were Summed Feature 3(iso-C15:0 2-OH and/or C16:1 ?7c)(25.49%),C16:0 N alcohol(13.50%),C16:0(12.46%),C17:0 10-methyl(11.07%),C18:0 ?7c(6.34%)and C17:1 ?8c(5.93%).Q-8 was the main respiratory quinone.The major polar lipids were phosphatidylethanolamine(PE)and phosphatidylglycerol(PG).The DNA G+C content of the type strain is 51.09 mol%(HPLC).Based on the distinct position and the combination of phenotypic and physiological characteristics,strain SS2-24T is considered to represent a novel species of the genus Lacimicrobium,for which the name Lacimicrobium sedminis sp.nov.is proposed.The type strain is SS2-241(=KCTC 52472T=MCCC 1H00181T). |
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