scholarly journals IDENTIFICATION AND ANTIMICROBIAL ACTIVITY OF ACTINOMYCETES STRAINS ISOLATED FROM SAMPLES COLLECTED IN THE COASTAL AREA OF HUE, DA NANG AND QUANG NAM PROVINCES, VIETNAM

2018 ◽  
Vol 15 (4) ◽  
pp. 737-744
Author(s):  
Cao Duc Tuan ◽  
Le Thi Hong Minh ◽  
Vu Thi Quyen ◽  
Nguyen Mai Anh ◽  
Doan Thi Mai Huong ◽  
...  
Keyword(s):  
Secondary Compounds ◽  
Inhibitory Effect ◽  
Common Source ◽  
Rrna Gene ◽  
Bioactive Substances ◽  
Reduced Pressure ◽  
Genus Streptomyces ◽  
Chemical Structures ◽  
Mic Minimum Inhibitory Concentration ◽  
Fermentation Broths

Microorganisms are of particular interest because of their ability to synthesize high-value secondary compounds and provide us with novel and diverse chemical structures. The most common source of antibiotics is Actinomycetes which provide around two-third of naturally occurring antibiotics, including many of medical importance. In this study, 81 strains of actinomycetes were isolated from 145 samples including: sediments, sponges, soft corals, echinoderms and starfish collected from three sea areas of Vietnam: Hue, Da Nang and Quang Nam. The strains were fermented in A+ medium and fermentation broths were extracted 5 times with ethyl acetate. The extracts were evaporated under reduced  pressure to yield crude extracts. Quantitative assay was used to determine MIC (Minimum inhibitory concentration) of extract against 7 reference strains. From the results of screening, Seven strains of actinomycetes that have the highest biological activity (Code: G244, G246, G261, G266, G278, G280 and G290) were chosen to be identified by morphological and phylogenetic based on 16S rRNA gene sequences. The results showed that 6 strains G246, G261, G266, G278, G280 and G290 belonged to the genus Streptomyces; and the strain G244 belonged to the genus Micromonospora. In particular, strains G244, G278, G280 were resistant 5/7 strains of microorganisms test, with values  MICs from 2 µg/mL to 256 µg/mL; and three strains G261, G266, G290 showed the inhibitory effect towards 4/7 strains of microorganisms test, with respective values MICs from 2 µg/mL to 256 µg/mL. Moreover, six of the seven selected strains were highly resistant to yeast Candida albicans ATCC10231 with MIC values from 2 µg/mL to 256 µg/mL. These results indicated that marine Actinomycetes in Vietnam are also a potential source to find bioactive substances.

scholarly journals Isolation, screening and identification of microorganisms having antimicrobial activity isolated from samples collected on seabed of Northeast Vietnam

2016 ◽  
Vol 14 (3) ◽  
pp. 539-547
Author(s):  
Lê Thị Hồng Minh ◽  
Vũ Thị Quyên ◽  
Nguyễn Mai Anh ◽  
Đoàn Thị Mai Hương ◽  
Brian T Murphy ◽  
...  
Keyword(s):  
Secondary Compounds ◽  
Inhibitory Effect ◽  
Rrna Gene ◽  
Bioactive Substances ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Chemical Structures ◽  
Screening And Identification ◽  
Fermentation Broths ◽  
Reference Strains

Microorganisms are especially interested in due to the ability to produce secondary compounds with high-value applications. Plenty of novel and diverse chemical structures have been found in the bioactive substances of microorganisms. In this study, we isolated 143 strains of bacteria and actinomycetes from 161 samples including: sediments, sponges, soft corals, echinoderms and starfish collected from three sea areas of Viet Nam: Ha Long - Cat Ba; Co To - ThanhLan; Bai Tu Long. The strains were fermented in A1 medium and then fermentation broths were extracted 5 times with ethyl acetate. The extraction residue screening test using 7 reference strains isolated 15 target strains with the highest biological activity. Most of these strains have dramatic inhibition on Gram positive bacteria: Enterococcus faecalis ATCC29212; Bacillus cereus ATCC13245  and Candida albicans ATCC10231 with MIC values  ​​less than or equal to the MIC value of the reference antibiotic. In particular, strain G057 was active against S. enterica ATCC 13076 and G002 inhibited E. coli ATCC25922 with respective values  ​​MICG057 = 8 µg/ ml, MICG002 = 256µg/ ml; and three strains G115, G119, G120 showed the inhibitory effect towards P. aeruginosa ATCC27853 with respective values ​​MICG115 = 64 µg/ ml, MICG119 = 32 µg/ ml and MICG120 = 32 µg/ ml. All 15 strains were then subjected to morphological and phylogenetic investigations based on 16S rRNA gene sequences. The results showed that 9 of 15 strains G016, G017, G019, G043, G044, G047, G068, G119 and G120 belonged to Genus Micromonospora; strains G039 and G065 were identified as Genus Stretomyces; G002 was  identified as Bacillus; G057 was  identified as Nocardiopsis; G115 was in Photobacterium and G121 belonged Oceanisphaera.

IDENTIFICATION AND ANTIMICROBIAL ACTIVITY OF ACTINOMYCETES STRAINS ISOLATED FROM SAMPLES IN THE COASTAL AREA OF THANH HOA – QUANG BINH – QUANG TRI

2018 ◽  
Vol 56 (4) ◽  
pp. 424
Author(s):  
Le Thi Hong Minh ◽  
Vu Thi Quyen
Keyword(s):  
Antimicrobial Activity ◽  
Inhibitory Concentration ◽  
Rrna Gene ◽  
Soft Corals ◽  
16S Rrna Gene Sequences ◽  
Reduced Pressure ◽  
Genus Streptomyces ◽  
Mic Minimum Inhibitory Concentration ◽  
Fermentation Broths ◽  
Reference Strains

In this study, we isolated 46 strains of actinomycetes from 40 samples including: sediments, sponges, soft corals, echinoderms and starfish collected from three sea areas of Vietnam: Thanh Hoa – Quang Binh – Quang Tri. The strains were fermented in A+ medium and fermentation broths were extracted 5 times with ethyl acetate then the extracts were evaporated under reduced  pressure to yield crude extracts. Quantitative assay was used to determine MIC (Minimum inhibitory concentration) of extract against 7 reference strains. From the results of screening, we chose 5 strains of actinomycetes that have the highest biological activity (Code: G212, G222, G233, G227 and G241). In particular,  strains G222, G233, G227 and G241 were resistant 6/7 strains of microorganisms test, with values  MICs from 64µg/ml to 256µg/ml; Moreover, All of the five strains were highly resistant to yeast Candida albicans ATCC10231. These strains were then subjected to morphological and phylogenetic investigations based on 16S rRNA gene sequences. The results showed that strains G212, G222 and G227 belonged to Genus Streptomyces; strains G233 and G241 were identified as Genus Micromonospora.

scholarly journals Isolation, screening and identification of microorganisms having antimicrobial activity and causing cytotoxicity isolated from sediment samples of the Vung Ang bay in Ha Tinh

2021 ◽  
Vol 19 (3) ◽  
pp. 557-568
Author(s):  
Vu Thi Quyen ◽  
Vu Thi Thu Huyen ◽  
Nguyen Mai Anh ◽  
Nguyen Hai Dang ◽  
Doan Thi Mai Huong ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Secondary Compounds ◽  
Antagonistic Activity ◽  
16S Rrna Sequence ◽  
Bioactive Substances ◽  
Genus Streptomyces ◽  
Chemical Structures ◽  
Screening And Identification

Actinomycetes has been extensively studied due to its ability to produce secondary compounds with high application value. Especially their antibiotic ability, more than 40% of antibiotics are derived from actinomycetes of which genus Streptomyces predominates. Moreover, marine actinomycetes have been being of great interest in recent years due to their ability to produce bioactive substances capable of providing diverse and novel chemical structures. In this study, from 8 samples of marine sediments collected in Vung Ang bay in Ha Tinh provinces, we have isolated 20 strains of actinomycetes. The strains were fermented in A1+ medium, the fermentation fluid was extracted 5 times with ethyl acetate, recovered sediment and determined antibacterial and cytotoxic activity. From the screening results, two strains with the highest antibacterial activity and highest cytotoxicity were selected ie., HT03 and HT06. Both strains had antagonistic activity of Enterococcus faecalis ATCC29212 with MICHT03= 32 μg/mL, MICHT06= 16μg/mL, with Stapphylococus aureus ATCC25923 with MICHT03= 64 μg/mL, MICHT06= 32 μg/mL and with Bacillus cereus ATCC 13245 has the same MIC = 16 μg / mL. In addition, the two strains HT03 and HT06 were able to strongly inhibit the yeast Candida albicans ATCC10231 with MICHT03= 16 μg/mL, MICHT06= 8 μg/mL. Especially, two strains, HT03 and HT06, exhibited very good toxicity on all 5 cancer cell lines (MCF-7 breast cancer cell; MDA-MB-231 breast cancer cell; lung cancer cell). NCI-H1975; HeLa cervical cancer cell; AGS gastric cancer cell) at both test concentrations of 30 µg/mL and 100µg/mL. By the analysis of 16S rRNA sequence, the results showed that the HT03 strain had the highest similarity (99.93%) to that of Streptomyces fradiaes and Streptomyces fradiae ATCC. The HT06 strain was defined to belong to Nocardiopsis synnemataformans with the 16S sequence identity of 99.89% to the Japanese standard Nocardiopsis synnemataformans DSM 44143 strain NBRC-102581.

scholarly journals Isolation, screening antimicrobial activity and identification of fungi from marine sediments of the area Thanh Lan, Co To, Vietnam

2020 ◽  
Vol 16 (4) ◽  
pp. 721-728
Author(s):  
Le Thi Hong Minh ◽  
Nguyen Mai Anh ◽  
Vu Thi Quyen ◽  
Vu Thi Thu Huyen ◽  
Doan Thi Mai Huong ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Marine Environment ◽  
Marine Sediments ◽  
18S Rrna ◽  
18S Rrna Gene ◽  
Biologically Active ◽  
Rrna Gene ◽  
Bioactive Substances ◽  
Fungal Strains ◽  
Chemical Structures

Marine environment is rich in natural product resources, including marine microorganisms, especially fungi which are not only seen as a potential source of highly applicable bioactive substances but also can provide for science new chemical structures. The objective of this study is to isolate and screen fungal strains with antibacterial activity from the marine environment. Twenty five strains of fungi were isolated from marine sediments of Thanh Lan, Co To island and assessed on antibiotic activity against 7 tested microbial strains, including three Gram-negative bacteria (Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, Salmonella enterica ATCC13076), three Gram-positive bacteria (Enterococcus faecalis ATCC29212, Stapphylococus aureus ATCC25923, Bacillus cereus ATCC 13245), and the yeast Candida albicans ATCC10231. The minimum inhibitory concentration (MIC) against the tested microorganisms was determined for the crude extracts obtained from the culture broths after ethyl acetate extraction and vacuum rotary evaporation. Three strains with the highest antimicrobial activity M26, M30 and M45 were capable of inhibiting 4 - 5 of the 7 tested microorganisms with MIC values from 64 to 256 μg/ml, depending on each tested strain. Morphological and phylogenetic investigations based on 18S rRNA gene sequences of the three selected strains showed that strains M26 and M30 belonged to the genus Penicillium, whereas strain M45 belonged to the genus Neurospora. The sequences of 18S rRNA gene of three strains M26, M30 and M45 were registered on GenBank database with accession numbers: MH673730, MH673731, MH673732, respectively. Research results showed that marine environment has a great potential in isolation of fungal strains for the search for antibacterial substances as well as other biologically active compounds.

scholarly journals Sarocladium and Lecanicillium Associated with Maize Seeds and Their Potential to Form Selected Secondary Metabolites

Biomolecules ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 98
Author(s):  
Lidia Błaszczyk ◽  
Agnieszka Waśkiewicz ◽  
Karolina Gromadzka ◽  
Katarzyna Mikołajczak ◽  
Jerzy Chełkowski
Keyword(s):  
Large Subunit ◽  
Solid Substrate ◽  
Rrna Gene ◽  
Decenoic Acid ◽  
Bioactive Substances ◽  
Lecanicillium Lecanii ◽  
Maize Seeds ◽  
Internally Transcribed Spacer ◽  
First Time

The occurrence and diversity of Lecanicillium and Sarocladium in maize seeds and their role in this cereal are poorly understood. Therefore, the present study aimed to investigate Sarocladium and Lecanicillium communities found in endosphere of maize seeds collected from fields in Poland and their potential to form selected bioactive substances. The sequencing of the internally transcribed spacer regions 1 (ITS 1) and 2 (ITS2) and the large-subunit (LSU, 28S) of the rRNA gene cluster resulted in the identification of 17 Sarocladium zeae strains, three Sarocladium strictum and five Lecanicillium lecanii isolates. The assay on solid substrate showed that S. zeae and S. strictum can synthesize bassianolide, vertilecanin A, vertilecanin A methyl ester, 2-decenedioic acid and 10-hydroxy-8-decenoic acid. This is also the first study revealing the ability of these two species to produce beauvericin and enniatin B1, respectively. Moreover, for the first time in the present investigation, pyrrocidine A and/or B have been annotated as metabolites of S. strictum and L. lecanii. The production of toxic, insecticidal and antibacterial compounds in cultures of S. strictum, S. zeae and L. lecanii suggests the requirement to revise the approach to study the biological role of fungi inhabiting maize seeds.

scholarly journals A Survey of Genetic Variation in Streptomyces Isolates Causing Potato Common Scab in the United States

2006 ◽  
Vol 96 (12) ◽  
pp. 1363-1371 ◽  
Author(s):  
Leslie A. Wanner
Keyword(s):  
United States ◽  
Genetic Variation ◽  
Common Scab ◽  
Disease Incidence ◽  
The United States ◽  
Rrna Gene ◽  
Population Genetic Study ◽  
Variable Regions ◽  
Genus Streptomyces ◽  
Characteristic Features

Common scab is a serious disease of potatoes and other root and tuber crops, affecting crop quality and market value. The disease is caused by gram positive soil bacteria in the genus Streptomyces. Disease incidence and severity vary in different locations and years; this is due in part to variation in the environment (weather) and genetic variation in potato cultivars. Little information is available on the contribution of genetic variation by the pathogen. To examine genetic diversity in different locations within the United States, streptomycetes were isolated from lesions on field-grown potatoes from six states. Isolates were classified into species based on sequence of variable regions in the 16s rRNA gene. The presence of genes associated with the recently described S. turgidiscabies pathogenicity island (PAI) was also determined. About half of the isolates belonged to S. scabies or S. europaeiscabiei based on 16s rDNA sequence, and had characteristic features of the PAI. They were found in all six states, and were pathogenic on potato and radish. The remaining isolates included pathogens and nonpathogens. They were varied in appearance, and represent several species, including one pathogenic species not previously reported. Some pathogenic isolates lacked one or more genes characteristic of the PAI, although all had genes for biosynthesis of the pathogenicity determinant thaxtomin. In this relatively small survey, regional differences in scab-causing streptomycetes were seen. This report furnishes tools and baseline data for population genetic study of scab-causing streptomycetes in the United States.

scholarly journals CONSTITUENTS AND INHIBITORY EFFECT ON HUMAN PATHOGENIC BACTERIA OF THE ROOTS OF SCUTELLARIA BAICALENSIS

2019 ◽  
Vol 57 (1) ◽  
pp. 7
Author(s):  
Duc Long Le ◽  
Huu Tung Nguyen ◽  
Thi Thom Nguyen ◽  
Gyung Ja Choi ◽  
Dinh Hoang Vu ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Scutellaria Baicalensis ◽  
Plant Materials ◽  
Chemical Structures ◽  
Human Pathogenic Bacteria ◽  
Antibiotic Effect ◽  
Study Results

Abstract-HCTN_16Methanol extract of the roots of Scutellaria baicalensis effectively inhibited the bacterial growth of human pathogenic bacteria Staphylococcus aureus ATCC 6538, Bacillus cereus ATCC 21768 and Bacillus subtilis ATCC 6633 at MICs of 2,000 µg/mL. n-Hexane, ethyl acetate and aqueous residues were prepared by successively partitioning the methanol extract with n-hexane and ethyl acetate. Among them, only ethyl acetate layer showed antibiotic effect; whereas n-hexane and aqueous layers were inactive against tested bacteria. The ethyl acetate residue was fractionated by silica gel column chromatography to afford three flavonoids and an oligosaccharide. Their chemical structures were elucidated as wogonin (SB1), baicalein (SB4), baicalin (SB5) and tetrasaccharide (SB10) on the basis of the analysis of NMR and MS spectroscopic data. The isolates were evaluated for in vitro inhibitory effect against human pathogenic bacteria using micro dilution bioassay method. Baicalein (SB4) showed a broad-spectrum inhibition against various human pathogenic bacteria. In particular, it was found to potently inhibit S. aureus ATCC 6538 and B. cereus ATCC 21768 with MICs of 9.5 and 38 µg/mL, respectively. The study results demonstrated antibiotic effect of the extracts from the roots of S. baicalensis and characterization of compounds isolated from the plant materials.

Streptomyces rhizophilus Causes Potato Common Scab Disease

Plant Disease ◽  
2021 ◽  
Author(s):  
Qi Wei ◽  
Jie Li ◽  
Shuai Yang ◽  
Wenzhong Wang ◽  
Fanxiang Min ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Common Scab ◽  
Bacterial Species ◽  
Economic Losses ◽  
Pcr Analysis ◽  
Rrna Gene ◽  
Heilongjiang Province ◽  
Epidemic Disease ◽  
Genus Streptomyces

Common scab (CS) caused by Streptomyces spp. is a significant soilborne potato disease that results in tremendous economic losses globally. Identification of CS-associated species of the genus Streptomyces can enhance understanding of the genetic variation of these bacterial species and is necessary for the control of this epidemic disease. The present study isolated Streptomyces strain 6-2-1(1) from scabby potatoes in Keshan County, Heilongjiang Province, China. PCR analysis confirmed that the strain harbored the characteristic Streptomyces pathogenicity island (PAI) genes (txtA, txtAB, nec1, and tomA). Pathogenicity assays proved that the strain caused typical scab lesions on potato tuber surfaces and necrosis on radish seedlings and potato slices. Subsequently, the strain was systemically characterized at morphological, physiological, biochemical and phylogenetic levels. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 6-2-1(1) shared 99.86% sequence similarity with Streptomyces rhizophilus JR-41T, isolated initially from bamboo in rhizospheric soil in Korea. PCR amplification followed by Sanger sequencing of the 16S rRNA gene of 164 scabby potato samples collected in Heilongjiang Province from 2019 to 2020 demonstrated that approximately 2% of the tested samples were infected with S. rhizophilus. Taken together, these results demonstrate that S. rhizophilus is capable of causing potato CS disease and may pose a potential challenge to potato production in Heilongjiang Province of China.

scholarly journals Classification of Streptomyces griseus (Krainsky 1914) Waksman and Henrici 1948 and related species and the transfer of ‘Microstreptospora cinerea’ to the genus Streptomyces as Streptomyces yanii sp. nov.

2005 ◽  
Vol 55 (4) ◽  
pp. 1605-1610 ◽  
Author(s):  
Zhiheng Liu ◽  
Yanlin Shi ◽  
Yamei Zhang ◽  
Zhihong Zhou ◽  
Zhitang Lu ◽  
...  
Keyword(s):  
Streptomyces Griseus ◽  
Taxonomic Status ◽  
Morphological Data ◽  
Rrna Gene ◽  
Phenotypic Properties ◽  
Phenotypic Data ◽  
Genus Streptomyces ◽  
Actinomycete Strain ◽  
Soil Actinomycete

A soil actinomycete, strain 80-133T, with the non-validly published name ‘Microstreptospora cinerea’, was the subject of a polyphasic study designed to clarify its taxonomic status. Comparative 16S rRNA gene sequence studies indicated that the organism belonged to the genus Streptomyces, a result in line with previous chemotaxonomic and morphological data. The strain belonged to the Streptomyces griseus clade, but could be distinguished from representatives of species assigned to this taxon by using DNA–DNA relatedness and phenotypic data. In light of these findings, it is proposed that the organism should be recognized as a novel species of the genus Streptomyces. The name proposed for this taxon is Streptomyces yanii sp. nov., with isolate 80-133T (=AS 4.1146T=JCM 3331T) as the type strain. It was also shown that representative strains of Streptomyces argenteolus, Streptomyces caviscabies, S. griseus and Streptomyces setonii belong to the same genomic species and have key phenotypic properties in common. It is proposed that S. caviscabies and S. setonii should be considered as later heterotypic synonyms of S. griseus and that S. argenteolus AS 4.1693T should also be assigned to this taxon.

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

2020 ◽  
Vol 8 (1) ◽  
pp. 77 ◽  
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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