Enhanced detection of antimicrobial activities and secondary metabolites production from Plantactinospora sp. KBS50 cultivated using the OSMAC fermentation approach

Aims@#A rare marine-derived actinomycete, Plantactinospora sp. KBS50, has been identified as a potential source of bioactive secondary metabolites compounds. The present study aimed to evaluate the secondary metabolites biosynthetic capability of strain KBS50 using the One Strain Many Compound (OSMAC) fermentation strategy. @*Methodology and results@#Strain KBS50 was fermented in a basal medium (ISP2) supplemented with selected biological and chemical elicitors, as well as cultivation at different pH value and incubation temperature. Statistical analysis revealed that the antimicrobial activities were significantly increased, as compared to the basal medium, ISP2. Similarly, the comparative High Performance Liquid Chromatography (HPLC) analysis showed an increase in secondary metabolites production, as well as the detection of potential new metabolites, particularly from the crude extracts of ISP2 medium supplemented with 1% (w/v) sodium chloride and with the culture filtrate of Aspergillus niger. The bioassay-guided fractionation showed that the extract of strain KBS50 contains multiple compounds with antibacterial activity against the Gram-positive strains. Further fractionation led to the isolation of two semi-pure compounds (compound 3 and 4) with bactericidal properties against Staphylococcus aureus. The Minimum Inhibitory Concentration (MIC) values of compound 3 and 4 were recorded at 7.81 μg/mL and 62.50 μg/mL, respectively. The minimum bactericidal concentration (MBC) for compound 3 was recorded at 15.63 μg/mL while the MBC for compound 4 was recorded as 125.00 μg/mL. @*Conclusion, significance and impact of study@#The OSMAC fermentation strategy used in this study had successfully enhanced the detection of antibiotics and secondary metabolites from Plantactinospora sp. KBS50. The bioassay-guided fractionation further established the capability of strain KBS50 as a source of bioactive secondary metabolite compounds with potent antimicrobial activity.

Antimicrobial activities of Plantactinospora sp. KBS50, a rare marine-derived actinomycete from the coastal area of Sarawak

Aims@#An actinomycete strain, designated KBS50, was isolated from a beach sediment sample collected from the Santubong area in Sarawak, Malaysia. This study reports on the identification, characterization and evaluation of the antimicrobial potential of this rare actinomycete. @*Methodology and results@#KBS50 was identified as a potentially new species of Plantactinospora genus using the 16S rRNA gene sequence analysis. The rare actinomycete showed distinct morphological and physiological characteristics from other species of Plantactinospora. KBS50 exhibited strong antagonistic activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and fungi (Aspergillus niger, Ganoderma boninense, and Rhizoctonia solani). The actinomycete also tested positive for proteolytic activity. Meanwhile, secondary screening of the cell-free culture broths and the ethyl acetate crude extracts detected antimicrobial activity against the Gram-positive bacteria only. The minimum inhibitory concentration of the crude extract against B. subtilis and S. aureus was 5.21±1.30 μg/mL and 15.63±0.00 μg/mL, respectively. @*Conclusion, significance and impact of study@#The results presented in this paper provided an insight into the capability of Plantactinospora sp. KBS50 as a potential source of bioactive secondary metabolites compounds. This study also showed that the marine-associated environment such as the coastal area in Sarawak can be a valuable source of unique actinomycetes that can be exploited for natural product discovery.

Sepration and antitumor activities of secondary metabolites from marine actino-mycete Nocardiopsis sp .SCSIO 11492 / 药学实践杂志

Objective To explore cytotoxic secondary metabolites from a marine actinomycete Nocardiopsis sp .SCSIO 11492 .Methods Isolation and purification were carried out by column chromatography over silica gel ,Sephadex LH-20 ,and ODS structures of the isolates were identified mainly by NMR spectroscopic data .And cytotoxic bioassay was performed using MTT method .Results Five compounds were identified as 2′-deoxyadenosine (1) ,2′-deoxythymidine (2) ,2′-deoxyuidine (3) ,uridine (4) ,1-O-palmitoyl-3-d-galactosyl-sn-glycerol spongilipid (5) .Compound 5 exhibited weak cytotoxic activity with IC50 value of 10 .9 μmol/L .Conclusion Five compounds were obtained from a marine actinomycete Nocardiopsis sp .SCSIO 11492 .All five compounds were reported for the first time from this genus .Compound 5 could be the bioactive compound re-sponsible for the cytotoxic activity of Nocardiopsis sp .SCSIO 11492 .

Salternamide E from a Saltern-derived Marine Actinomycete Streptomyces sp

Comprehensive chemical analysis of extracts and fractions of marine actinomycete strains led to the discovery of a new minor secondary metabolite, salternamide E (1), from a saltern-derived halophilic Streptomyces strain. The planar structure of salternamide E (1) was elucidated by a combinational analysis of spectroscopic data including NMR, MS, UV, and IR. The absolute configuration of salternamide E (1) was determined by circular dichroism spectroscopic analysis. Salternamide E displayed weak cytotoxicity against various human carcinoma cell lines.

Isolation and Identification on One Marine Actinomycete Strain with Antitumor Activity / 微生物学通报

One marine actinomycete strain FIM02-523 was isolated from marine soil in the East China Sea in Fujian Province. The fermentation broth of strain FIM02-523 exhibited potent antitumor activities. Strain FIM02-523 grew well on most media tested, the colonies were orange to dark brown but lacked aerial hy-phae, no diffusible pigments were observed. Phylogenetic, chemotaxonomic, morphological analyses, physiological and biochemical characteristics demonstrated that strain FIM02-523 belong to the genus Mi-cromonospora, may be a strain of the type species Micromonospora chalcea.

Isolation and Identification of One Marine Actinomycete Strain Exhibiting Antitumor Activity / 微生物学通报

The fermentation broth of one actinomycete strain ACMA006 strongly inhibited growth of many tumor cells and some microorganisms, but its cytotoxicity to human normal cells were weak. Strain ACMA006 grow well on most tested media, producing exuberant vegetative hyphae and aerial hyphae. Its optimization temperature is 28?C. Phyloge-netic analysis based on 16S rDNA sequence showed that strain ACMA006 was closely related to one of the genus Streptomycetes (S.cavourensis subsp. washingtonensis) with 16S rDNA sequence similarity values of 100%, but had many differences in other features including its morphology, physiological and biochemical characteristics. The pre-liminary study supported the view that the strain ACMA006 represented a new strain of the S.cavourensis subsp. wash-ingtonensis.

Isolation and Identification of Marine Actinomycete JMC06001 Exhibiting Strong Antibacterial Activity / 微生物学通报

One slightly halophilic marine actinomycete strain JMC 06001 was isolated from a saline mud sample collected from the Island Naozhou in the South China Sea,near Zhanjiang,a city of southern China. The fermentation broth of strain JMC 06001 strongly inhibited the growth of Staphylococcus aureaus,Sarcina lutea,Bacillus subtilis,Escherichia coli,Micrococcus luteus and Proteus vulgaris.The combination of morphology,physiological and biochemical characteristics,chemotaxonomic data and 16S rRNA gene sequence analysis supported the view that strain JMC 06001 belong to a known species of the genus Steptomyces, S.peucetius.The strain studied grown well on most media tested,with white aeriel hyphae and pale yellow to pale brown substance hyphae.Yellow diffusible pigments were produced on oatmeal agar(ISP 3), potato extract agar and glucose/asparagines agar,and pale brown to deep brown diffusible pigments were produced on yeast extract/malt extract agar(ISP 2),glycerol/asparagine agar(ISP5),peptone-yeast ext-Fe agar(ISP 6)and nutrient agar.Growth occurred at 4℃～40℃and pH 6.0～9.0,with optimum growth at 28℃and pH 7.0.The tolerant range of NaCl was 0～1.5 mol/L,with best growth occurring in media containing 0.2～0.5 mol/L NaC1.