Taxonomic Characterization and Secondary Metabolite Analysis of NEAU-wh3-1: An Embleya Strain with Antitumor and Antibacterial Activity

Cancer is a serious threat to human health. With the increasing resistance to known drugs, it is still urgent to find new drugs or pro-drugs with anti-tumor effects. Natural products produced by microorganisms have played an important role in the history of drug discovery, particularly in the anticancer and anti-infective areas. The plant rhizosphere ecosystem is a rich resource for the discovery of actinomycetes with potential applications in pharmaceutical science, especially Streptomyces. We screened Streptomyces-like strains from the rhizosphere soil of wheat (Triticum aestivum L.) in Hebei province, China, and thirty-nine strains were obtained. Among them, the extracts of 14 isolates inhibited the growth of colon tumor cell line HCT-116. Strain NEAU-wh-3-1 exhibited better inhibitory activity, and its active ingredients were further studied. Then, 16S rRNA gene sequence similarity studies showed that strain NEAU-wh3-1 with high sequence similarities to Embleya scabrispora DSM 41855T (99.65%), Embleya hyalina MB891-A1T (99.45%), and Streptomyces lasii 5H-CA11T (98.62%). Moreover, multilocus sequence analysis based on the five other house-keeping genes (atpD, gyrB, rpoB, recA, and trpB) and polyphasic taxonomic approach comprising chemotaxonomic, phylogenetic, morphological, and physiological characterization indicated that the isolate should be assigned to the genus Embleya and was different from its closely related strains, therefore, it is proposed that strain NEAU-wh3-1 may be classified as representatives of a novel species of the genus Embleya. Furthermore, active substances in the fermentation broth of strain NEAU-wh-3-1 were isolated by bioassay-guided analysis and identified by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. Consequently, one new Zincophorin analogue together with seven known compounds was detected. The new compound showed highest antitumor activity against three human cell lines with the 50% inhibition (IC50) values of 8.8–11.6 μg/mL and good antibacterial activity against four pathogenic bacteria, the other known compounds also exhibit certain biological activity.

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Taxonomic Characterization, and Secondary Metabolite Analysis of Streptomyces triticiradicis sp. nov.: A Novel Actinomycete with Antifungal Activity

Microorganisms ◽

10.3390/microorganisms8010077 ◽

2020 ◽

Vol 8 (1) ◽

pp. 77 ◽

Cited By ~ 4

Author(s):

Zhiyin Yu ◽

Chuanyu Han ◽

Bing Yu ◽

Junwei Zhao ◽

Yijun Yan ◽

...

Keyword(s):

Antifungal Activity ◽

16S Rrna ◽

Sequence Similarity ◽

Triticum Aestivum L ◽

Biosynthetic Gene Cluster ◽

Rrna Gene ◽

Phenotypic Properties ◽

Genus Streptomyces ◽

Antagonistic Microorganisms ◽

Taxonomic Characterization

The rhizosphere, an important battleground between beneficial microbes and pathogens, is usually considered to be a good source for isolation of antagonistic microorganisms. In this study, a novel actinobacteria with broad-spectrum antifungal activity, designated strain NEAU-H2T, was isolated from the rhizosphere soil of wheat (Triticum aestivum L.). 16S rRNA gene sequence similarity studies showed that strain NEAU-H2T belonged to the genus Streptomyces, with high sequence similarities to Streptomyces rhizosphaerihabitans NBRC 109807T (98.8%), Streptomyces populi A249T (98.6%), and Streptomyces siamensis NBRC 108799T (98.6%). Phylogenetic analysis based on 16S rRNA, atpD, gyrB, recA, rpoB, and trpB gene sequences showed that the strain formed a stable clade with S. populi A249T. Morphological and chemotaxonomic characteristics of the strain coincided with members of the genus Streptomyces. A combination of DNA–DNA hybridization results and phenotypic properties indicated that the strain could be distinguished from the abovementioned strains. Thus, strain NEAU-H2T belongs to a novel species in the genus Streptomyces, for which the name Streptomyces triticiradicis sp. nov. is proposed. In addition, the metabolites isolated from cultures of strain NEAU-H2T were characterized by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. One new compound and three known congeners were isolated. Further, genome analysis revealed that the strain harbored diverse biosynthetic potential, and one cluster showing 63% similarity to natamycin biosynthetic gene cluster may contribute to the antifungal activity. The type strain is NEAU-H2T (= CCTCC AA 2018031T = DSM 109825T).

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Sponge-Associated Actinobacteria: Morphological Character and Antibacterial Activity against Pathogenic Bacteria

Jurnal Sumberdaya Hayati ◽

10.29244/jsdh.3.1.21-26 ◽

2017 ◽

Vol 3 (1) ◽

pp. 21-26

Author(s):

SASMIATI FARACH DITA ◽

SRI BUDIARTI ◽

YULIN LESTARI

Keyword(s):

Antimicrobial Activity ◽

Antibacterial Activity ◽

Pathogenic Bacteria ◽

Marine Ecosystem ◽

Morphological Characteristics ◽

Antibacterial Activities ◽

Morphological Characters ◽

Antimicrobial Activities ◽

Shigella Dysenteriae ◽

Rrna Gene

Sponge-associated actinobacteria may diverse and have potency to produce bioactive compounds. Diversity and antimicrobial activity of indigenous sponge-associated actinobacteria isolated from the marine ecosystem in Indonesia have not much been explored. This work aimed to assess morphological and antibacterial activity of sponge-associated actinobacteria. The morphological characteristics were examined based on their color of aerial and substrate mycelia, and pigmentation, while antibacterial activities were assayed using the antagonist technique. The selected actinobacterial isolate was identified using 16S rRNA gene. Various sponge-associated actinobacteria were successfully isolated from Hyrtios sp., Callyspongia sp., and Neofibularia sp. sponges. A total of 62 actinobacterial isolates were obtained, and each isolate showed a variety of morphological characters, which could be seen in aerial mass color, substrate mass color, and pigmentation. Actinobacterial isolates were tested against human pathogenic bacteria, i.e. Staphylococcus aureus and Methicillin-Resistant S. aureus, representing Gram-positive, and Escherichia coli EPEC K1-1 and Shigella dysenteriae, representing Gram-negative. Most of actinobacterial isolates had antimicrobial activities at least against one of pathogenic bacteria. High activity was shown by NOHa.2, isolated from Neofibularia, and HRHa.5 isolated from Hyrtios. The NOHa.2 showed the highest antimicrobial activity against S. dysenteriae, meanwhile, HRHa.5 showed antimicrobial activity against 3 of 4 tested bacterial pathogens. These data showed diversity of sponge-asccociated actinobacteria from marine ecosystem in Indonesia, and several of them have potency as source of antibacterial compounds

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Antagonistic Potential of Soil Streptomyces Isolates from Southern Thailand to Inhibit Foodborne Bacterial Pathogens

International Journal of Microbiology ◽

10.1155/2021/2545441 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Waenurama Chemoh ◽

Wahida Bin-Ismail ◽

Sawitree Dueramae

Keyword(s):

Antibacterial Activity ◽

Pathogenic Bacteria ◽

Bacterial Pathogens ◽

Antagonistic Activity ◽

Rrna Gene ◽

Rice Soils ◽

Streptomyces Species ◽

Genus Streptomyces ◽

Crude Extracts ◽

Broth Microdilution Method

Streptomyces are well known for their competence to produce thousands of bioactive secondary metabolites and enzymes. This study aimed to assess the inhibitory activities of crude extracts from diverse Streptomyces collected from rice soils in Narathiwat, Thailand, against foodborne bacterial pathogens. In total, 136 Actinomycete isolates were screened using a cross-streak method for the ability to produce effective metabolites against 5 pathogenic bacteria. Out of these, 19 (13.97%) isolates had antibacterial activity against at least one tested bacterium. Most of the isolates could strongly suppress the growth of S. aureus ATCC25923 and B. cereus MTCC430 except P. aeruginosa ATCC27853. On the basis of morphological, cultural, and biochemical characteristics, all potent isolates exhibited typical features that fitted the genus Streptomyces. Two of the 7 selected ethyl acetate crude extracts had good antagonistic activity against S. aureus ATCC25923 and B. cereus MTCC430 when tested using the agar well diffusion assay. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the 2 extracts evaluated using the colorimetric broth microdilution method ranged from 256 to >1,024 μg/ml against the tested bacteria. The partial nucleotide sequences of the 16S rRNA gene led to identifying both active isolates as Streptomyces species. These active Streptomyces isolates could provide an interesting source for generating innumerable natural compounds with antibacterial activity that can presumably be developed to fight bacterial pathogens in the near future.

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Evaluation of the probiotic and postbiotic potential of lactic acid bacteria from artisanal dairy products against pathogens

The Journal of Infection in Developing Countries ◽

10.3855/jidc.13404 ◽

2021 ◽

Vol 15 (01) ◽

pp. 102-112

Author(s):

Nazar Hussain ◽

Muhammad Tariq ◽

Per Erik Joakim Saris ◽

Arsalan Zaidi

Keyword(s):

Antibacterial Activity ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Pathogenic Bacteria ◽

16S Rrna Gene Sequencing ◽

Lactobacillus Delbrueckii ◽

Human Consumption ◽

Rrna Gene ◽

Microdilution Method

Introduction: Probiotic and postbiotic potential of thirty-two strains of lactic acid bacteria (LAB), obtained earlier from artisanal dairy sources in Pakistan, have been investigated against major multi-drug resistant (MDR) and food borne pathogenic bacteria. Methodology: LAB strains were identified by 16S rRNA gene sequencing and their antibacterial activity was assessed by the microdilution method. Four LAB isolates, Weissella confusa PL6, Enterococcus faecium PL7, and Lactobacillus delbrueckii PL11 and PL13 were shortlisted. Their ability to degrade lactose and safety for human consumption in terms of hemolysis and antibiotic susceptibility were assessed in vitro. The antibacterial components in the cell-free supernatants (CFSs) of isolate cultures were characterized biochemically by HPLC. Results: Acid neutralization but not protease treatment abolished the antibacterial activity of CFSs. Lactic, acetic and propionic acids were the main acids in the CFSs, and acid production peaked in the stationary phase of growth. The antibacterial activity of the LAB cultures resulted from secretion of organic acids that lowered the pH. The strains exhibited variable ability to degrade lactose and were non-hemolytic and susceptible to the most common antibiotics. Conclusions: These LAB strains are probiotic candidates for further investigation of their postbiotic role in naturally preserving processed foods and for attenuation of lactose intolerance.

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Enrichment and Physiological Characterization of a Novel Nitrospira-Like Bacterium Obtained from a Marine Sponge

Applied and Environmental Microbiology ◽

10.1128/aem.00320-10 ◽

2010 ◽

Vol 76 (14) ◽

pp. 4640-4646 ◽

Cited By ~ 58

Author(s):

Sandra Off ◽

Mashal Alawi ◽

Eva Spieck

Keyword(s):

Marine Sponge ◽

Sea Water ◽

Enrichment Culture ◽

Sequence Similarity ◽

Rrna Gene ◽

The Novel ◽

Physiological Characterization ◽

Inhibition Of Growth ◽

Nitrite Oxidizing Bacteria ◽

Aplysina Aerophoba

ABSTRACT Members of the nitrite-oxidizing genus Nitrospira are most likely responsible for the second step of nitrification, the conversion of nitrite (NO2 −) to nitrate (NO3 −), within various sponges. We succeeded in obtaining an enrichment culture of Nitrospira derived from the mesohyl of the marine sponge Aplysina aerophoba using a traditional cultivation approach. Electron microscopy gave first evidence of the shape and ultrastructure of this novel marine Nitrospira-like bacterium (culture Aa01). We characterized these bacteria physiologically with regard to optimal incubation conditions, especially the temperature and substrate range in comparison to other Nitrospira cultures. Best growth was obtained at temperatures between 28°C and 30°C in mineral medium with 70% North Sea water and a substrate concentration of 0.5 mM nitrite under microaerophilic conditions. The Nitrospira culture Aa01 is very sensitive against nitrite, because concentrations higher than 1.5 mM resulted in a complete inhibition of growth. Sequence analyses of the 16S rRNA gene revealed that the novel Nitrospira-like bacterium is separated from the sponge-specific subcluster and falls together with an environmental clone from Mediterranean sediments (98.6% similarity). The next taxonomically described species Nitrospira marina is only distantly related, with 94.6% sequence similarity, and therefore the culture Aa01 represents a novel species of nitrite-oxidizing bacteria.

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Coupling Microplate-Based Antibacterial Assay with Liquid Chromatography for High-Resolution Growth Inhibition Profiling of Crude Extracts: Validation and Proof-of-Concept Study with Staphylococcus aureus

Molecules ◽

10.3390/molecules26061550 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1550

Author(s):

Hamidreza Ardalani ◽

Syariful Anam ◽

Kresten J.K. Kromphardt ◽

Dan Staerk ◽

Kenneth T. Kongstad

Keyword(s):

Staphylococcus Aureus ◽

High Resolution ◽

Growth Inhibition ◽

Pathogenic Bacteria ◽

Fermentation Broth ◽

Bioactive Constituents ◽

Crude Extracts ◽

Ic50 Values ◽

Alternaria Sp ◽

Development And Validation

With the identification of novel antibiotics from nature being pivotal in the fight against human pathogenic bacteria, there is an urgent need for effective methodologies for expedited screening of crude extracts. Here we report the development and validation of a simple and dye-free antimicrobial assay in 96-well microplate format, for both determination of IC50 values and high-resolution inhibition profiling to allow pin-pointing of bioactive constituents directly from crude extracts. While commonly used antimicrobial assays visualize cell viability using dyes, the developed and validated assay conveniently uses OD600 measurements directly on the fermentation broth. The assay was validated with an investigation of the inhibitory activity of DMSO against Staphylococcus aureus, temperature robustness, interference by coloured crude extracts as well as inter-day reproducibility. The potential for high-resolution S. aureus growth inhibition profiling was evaluated on a crude extract of an inactive Alternaria sp., spiked with ciprofloxacin.

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Antibacterial potential and ethnomedical relevance of Kumaun Himalayan Gymnosperms

The Journal of Phytopharmacology ◽

10.31254/phyto.2016.5505 ◽

2016 ◽

Vol 5 (5) ◽

pp. 190-200

Author(s):

Savita Joshi ◽

◽

S.C. Sati ◽

Parikshit Kumar ◽

◽

...

Keyword(s):

Antibacterial Activity ◽

Pathogenic Bacteria ◽

Ethanol Extract ◽

Chloroform Extract ◽

New Drugs ◽

Diffusion Method ◽

Taxus Baccata ◽

Cedrus Deodara ◽

Kumaun Himalaya ◽

Antibacterial Potential

Ethnomedicinal information is one of the powerful criteria for new drugs discoveries therefore; present investigation was carried out to evaluate the ethnomedicinal and antibacterial potential of traditional Kumaun Himalayan gymnosperms. Besides, an antibacterial value index and relative antibacterial activity of studied plants have been established. Forty four plant leaves extracts in different organic solvents (methanol, ethanol, chloroform and hexane) of 11 gymnosperms (Araucaria cunninghamii, Biota orientalis, Cedrus deodara, Cephalotaxus griffithi, Cryptomeria japonica Cupressus torulosa, Ginkgo biloba, Juniperus communis, Picea smithiana, Pinus wallichiana and Taxus baccata) occurring in Kumaun Himalaya were screened for their antimicrobial activity against five pathogenic bacteria using disc diffusion method. The antibacterial activity of studied gymnospermic plant extracts against a panel of bacteria was found effective at 1000 µg/ml. The MIC and MBC values of each extract (where ZOI ≥ 15 mm) were also determined. The methanol extract of screened gymnosperms were found the most effective against all the bacteria (54% to 81%), followed by ethanol extract (45-72%), hexane extract (18-27%), while in chloroform extract it ranged 9-27% only. The extracts of G. biloba exhibited superior Relative Antibacterial Activity (RAA, 20%), followed by A. cunninghamii and P. wallichiana (12% RAA, each). The lowest RAA value was observed for C. torulosa (1%). All data were also analyzed for determination of an Antibacterial Value Index (ABVI) for each studied species of gymnosperm. G. biloba had maximum ABVI i.e. 90 % followed by A. cunninghamii and P. wallichiana (ABVI, 55% each). C. torulosa showed the least ABVI and RAA i.e. 5% and 11%, respectively. The present work fully highlighted the utility of traditionally known 11 gymnosperms of Kumaun Himalaya for their antibacterial activities against pathogenic bacteria.

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Identification and Antibacterial Characterization of Endophytic Fungi from Artemisia sieberi

International Journal of Microbiology ◽

10.1155/2021/6651020 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Ibtisam Mohammed Ababutain ◽

Sahar Khamees Aldosary ◽

Amal Abdulaziz Aljuraifani ◽

Azzah Ibrahim Alghamdi ◽

Amira Hassan Alabdalall ◽

...

Keyword(s):

Antibacterial Activity ◽

Ethyl Acetate ◽

Molecular Identification ◽

Endophytic Fungi ◽

Pathogenic Bacteria ◽

Antibacterial Properties ◽

Diffusion Method ◽

Rrna Gene ◽

Gram Positive ◽

Artemisia Sieberi

Endophytic fungi serve as a reservoir for important secondary metabolites. The current study focused on the antibacterial properties of endophytic fungi isolated from Artemisia sieberi. Initially, six endophytic fungi were isolated and purified from the stem of A. sieberi. Endophytic fungi were identified by morphological characteristics, as well as by molecular identification using 18S rRNA gene sequencing method. All the six isolates were subjected to the preliminary screening for their antibacterial activity against nine important pathogenic bacteria using the disk-diffusion method. Crude extracts of the most active isolate were obtained using ethyl acetate. Antibacterial activity of the ethyl acetate extract was evaluated using well diffusion method on the selected isolate. The antibacterial efficiency of the selected isolate was evaluated by determining the Minimum Inhibitory Concentration (MIC). MIC values were in appreciable quantity against both Gram-positive and Gram-negative bacteria ranging from 3.125 to 6.25 µg/mL and 12.5 to 50 µg/mL, respectively. This result indicated that Gram-positive bacteria were more susceptible to the endophytic fungi extract. Moreover, the molecular identification results revealed that all the isolates belong to Ascomycota and represented Aspergillus and Penicillium genera and three species: A. oryzae (three isolates), A. niger (one isolate), and P. chrysogenum (two isolates). All six endophytic fungi were able to inhibit the growth of at least two of the tested bacteria. Among the isolated strains, isolate AS2, which identified as P. chrysogenum, exhibited the highest antibacterial activity against all nine tested bacteria and was higher than or equal to the positive control against most of the tested bacteria. Future studies are required to isolate and identify these bioactive substances, which can be considered as a potential source for the synthesis of new antibacterial drugs to treat infectious diseases.

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A Streptomyces sp. NEAU-HV9: Isolation, Identification, and Potential as a Biocontrol Agent against Ralstonia solanacearum of Tomato Plants

Microorganisms ◽

10.3390/microorganisms8030351 ◽

2020 ◽

Vol 8 (3) ◽

pp. 351 ◽

Cited By ~ 4

Author(s):

Ling Ling ◽

Xiaoyang Han ◽

Xiao Li ◽

Xue Zhang ◽

Han Wang ◽

...

Keyword(s):

Antibacterial Activity ◽

Ralstonia Solanacearum ◽

Actinomycin D ◽

Biological Control Agent ◽

Sequence Similarity ◽

Morphological Characteristics ◽

Rrna Gene ◽

Tomato Seedling ◽

Genus Streptomyces ◽

Tomato Seedlings

Ralstonia solanacearum is an important soil-borne bacterial plant pathogen. In this study, an actinomycete strain named NEAU-HV9 that showed strong antibacterial activity against Ralstonia solanacearum was isolated from soil using an in vitro screening technique. Based on physiological and morphological characteristics and 98.90% of 16S rRNA gene sequence similarity with Streptomyces panaciradicis 1MR-8T, the strain was identified as a member of the genus Streptomyces. Tomato seedling and pot culture experiments showed that after pre-inoculation with the strain NEAU-HV9, the disease occurrence of tomato seedlings was effectively prevented for R. solanacearum. Then, a bioactivity-guided approach was employed to isolate and determine the chemical identity of bioactive constituents with antibacterial activity from strain NEAU-HV9. The structure of the antibacterial metabolite was determined as actinomycin D on the basis of extensive spectroscopic analysis. To our knowledge, this is the first report that actinomycin D has strong antibacterial activity against R. solanacearum with a MIC (minimum inhibitory concentration) of 0.6 mg L−1 (0.48 μmol L−1). The in vivo antibacterial activity experiment showed that actinomycin D possessed significant preventive efficacy against R. solanacearum in tomato seedlings. Thus, strain NEAU-HV9 could be used as BCA (biological control agent) against R. solanacearum, and actinomycin D might be a promising candidate for a new antibacterial agent against R. solanacearum.

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Streptomyces abietis sp. nov., a cellulolytic bacterium isolated from soil of a pine forest

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.053025-0 ◽

2013 ◽

Vol 63 (Pt_12) ◽

pp. 4754-4759 ◽

Cited By ~ 9

Author(s):

Katsuhiko Fujii ◽

Masataka Satomi ◽

Youhei Fukui ◽

Shun Matsunobu ◽

Youji Morifuku ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Sequence Similarity ◽

Rrna Gene ◽

Cellulolytic Bacterium ◽

Cellulolytic Bacteria ◽

Dna Base Composition ◽

Content Type ◽

Physiological Characterization ◽

Link Type

Cellulolytic bacteria A191T, A192 and A193 isolated from the soil of Sakhalin fir forest in Hokkaido, Japan were studied phenotypically, genotypically and phylogenetically. Analysis of their 16S rRNA gene and gyrB sequences and DNA base composition suggested that these isolates were conspecific and members of the genus Streptomyces . However, levels of 16S rRNA gene and gyrB sequence similarity between the isolates and the type strains of their closest relatives in the genus Streptomyces were no higher than 97.9 and 95.0 %, respectively, implying that these isolates were distinctive. Moreover, the results of DNA−DNA hybridization experiments and physiological characterization clearly differentiated these isolates from their closest neighbours. It is therefore concluded that these isolates represent a novel species of the genus Streptomyces , for which the name Streptomyces abietis is proposed. The type strain is A191T ( = NBRC 109094T = DSM 42080T).

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