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 ◽  
...  

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.

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 ◽  
...  

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.


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 ◽  
...  

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.


2020 ◽  
Vol 6 (2) ◽  
pp. 133-139
Author(s):  
Tri Mayanti ◽  
Nur Insani Amir ◽  
Dewa Gede Katja ◽  
Sofa Fajriah ◽  
Ahmad Darmawan ◽  
...  

Three steroids, 3α-hydroxystigmast-5(6), 22-diene-7-one (1), stigmasterol (2) and 3-hydroxy-7β-methoxystigmast-5(6)-ene (3), were isolated from the stem bark of Dysoxylum nutans. The chemical structures were identified by spectroscopic data, which includes IR, 1D-NMR, 2D-NMR, and HR-TOFMS as well as by comparing previously reported spectral data. Compounds 1-3 were tested for cytotoxic effect against MCF-7 breast cancer cell lines and compound 1 showed the strongest cytotoxic activity with an IC50 value of 20.13 ± 0.06 μM.


2008 ◽  
Vol 68 (S 01) ◽  
Author(s):  
J Jung ◽  
A Nedeljkovic-Kurepa ◽  
B Glover ◽  
DT Curiel ◽  
RK Schmutzler ◽  
...  

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