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result(s) for
"Quach, Ngoc Tung"
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Endophytic Actinobacteria Associated with Dracaena cochinchinensis Lour.: Isolation, Diversity, and Their Cytotoxic Activities
by
Quach, Ngoc-Tung
,
Khieu, Thi-Nhan
,
Vu, Thu-Trang
in
Actinobacteria
,
Actinobacteria - classification
,
Actinobacteria - isolation & purification
2017
Dracaena cochinchinensis Lour. is an ethnomedicinally important plant used in traditional Chinese medicine known as dragon’s blood. Excessive utilization of the plant for extraction of dragon’s blood had resulted in the destruction of the important niche. During a study to provide a sustainable way of utilizing the resources, the endophytic Actinobacteria associated with the plant were explored for potential utilization of their medicinal properties. Three hundred and four endophytic Actinobacteria belonging to the genera Streptomyces, Nocardiopsis, Brevibacterium, Microbacterium, Tsukamurella, Arthrobacter, Brachybacterium, Nocardia, Rhodococcus, Kocuria, Nocardioides, and Pseudonocardia were isolated from different tissues of D. cochinchinensis Lour. Of these, 17 strains having antimicrobial and anthracyclines-producing activities were further selected for screening of antifungal and cytotoxic activities against two human cancer cell lines, MCF-7 and Hep G2. Ten of these selected endophytic Actinobacteria showed antifungal activities against at least one of the fungal pathogens, of which three strains exhibited cytotoxic activities with IC50-values ranging between 3 and 33 μg·mL−1. Frequencies for the presence of biosynthetic genes, polyketide synthase- (PKS-) I, PKS-II, and nonribosomal peptide synthetase (NRPS) among these 17 selected bioactive Actinobacteria were 29.4%, 70.6%, and 23.5%, respectively. The results indicated that the medicinal plant D. cochinchinensis Lour. is a good niche of biologically important metabolites-producing Actinobacteria.
Journal Article
Functional Genomic and Phenotypic Analysis of Lactiplantibacillus pentosus P7 Isolated from Pickled Mustard Greens Reveals Capacity for Exopolysaccharide, B-Vitamin, and Lactic Acid Production
2025
Lactiplantibacillus pentosus is a lactic acid bacterium frequently detected in various fermented foods; however, the genomic traits related to its biotechnological potential have been underexplored. In this study, 34 catalase-negative isolates were obtained from pickled mustard greens, among which strain P7 exhibited the highest exopolysaccharide (EPS) yield (781.9 ± 14.7 mg/L) and was capable of growing in a chemically defined medium lacking riboflavin. Whole-genome sequencing revealed a 3,749,478 bp circular chromosome with 46.5% G + C content and 3389 protein-coding genes. A phylogenomic analysis identified P7 as L. pentosus. Functionally, 1 mg/mL EPS extracted from P7 demonstrated strong antioxidant activity, with DPPH and hydroxyl radical scavenging capacities of 89.8 ± 4.6% and 76.5 ± 9.5%, respectively. The use of 0.2 mg/mL EPS also protected Saccharomyces cerevisiae cells from oxidative stress. A comparative genomic analysis indicated the presence of nearly complete biosynthetic pathways for riboflavin, folate, and pyridoxine. High-performance liquid chromatography (HPLC) confirmed the production of 23.8 ± 0.4 µg/mL riboflavin, 36.6 ± 0.6 µg/mL folic acid, and 0.42 ± 0.02 µg/mL pyridoxine in the culture supernatant, which have not been previously reported. Additionally, strain P7 produced 91.2 ± 12.3 g/L of lactic acid after 24 h of incubation. These results support the potential of L. pentosus P7 as a candidate for industrial applications in the production of EPS, B-group vitamins, and lactic acid.
Journal Article
Plant-derived bioactive compounds produced by Streptomyces variabilis LCP18 associated with Litsea cubeba (Lour.) Pers as potential target to combat human pathogenic bacteria and human cancer cell lines
by
Nguyen, Xuan Canh
,
Phi, Quyet Tien
,
Nguyen, Quang Huy
in
A549 Cells
,
Actinomycetes
,
Anti-Bacterial Agents - pharmacology
2021
To date, endophytic actinomycetes have been well-documented as great producers of novel antibiotics and important pharmaceutical leads. The present study aimed to evaluate potent bioactivities of metabolites synthesized by the strain LCP18 residing in the Vietnamese medicinal plant
Litsea cubeba
(Lour.) Pers towards human pathogenic bacteria and human cancer cell lines. Endophytic actinomycete strain LCP18 showed considerable inhibition against seven bacterial pathogens and three human tumor cell lines and was identified as species
Streptomyces variabilis
. Strain
S. variabilis
LCP18 was phenotypically resistant to fosfomycin, trimethoprim-sulfamethoxazole, dalacin, cefoxitin, rifampicin, and fusidic acid and harbored the two antibiotic biosynthetic genes such as PKS-II and NRPS. Further purification and structural elucidation of metabolites from the LCP18 extract revealed five plant-derived bioactive compounds including isopcrunetin, genistein, daidzein, syringic acid, and daucosterol. Among those, isoprunetin, genistein, and daidzein exhibited antibacterial activity against
Salmonella typhimurium
ATCC 14,028 and methicillin-resistant
Staphylococcus epidermidis
ATCC 35,984 with the MIC values ranging from 16 to 128 µg/ml. These plant-derived compounds also exhibited cytotoxic effects against human lung cancer cell line A549 with IC
50
values of less than 46 μM. These findings indicated that endophytic
S. variabilis
LCP18 can be an alternative producer of plant-derived compounds which significantly show potential applications in combating bacterial infections and inhibition against lung cancer cell lines.
Journal Article
Genome-Guided Investigation Provides New Insights into Secondary Metabolites of Streptomyces parvulus SX6 from Aegiceras corniculatum
by
Nguyen Vu, Thi Hanh
,
Dudhagara, Pravin
,
An Nguyen, Thi Thu
in
Actinomycin
,
Aegiceras corniculatum
,
Anticancer properties
2022
Whole-genome sequencing and genome mining are recently considered an efficient approach to shine more light on the underlying secondary metabolites of
. The present study unearths the biosynthetic potential of endophytic SX6 as a promising source of biologically active substances and plant-derived compounds for the first time. Out of 38 isolates associated with
(L.) Blanco,
SX6 was highly active against
ATCC® 9027™ and methicillin-resistant
(MRSE) ATCC® 35984™. Additionally,
SX6 culture extract showed strong cytotoxicity against Hep3B, MCF-7, and A549 cell lines at a concentration of 30 μg/ml, but not in non-cancerous HEK-293 cells. The genome contained 7.69 Mb in size with an average G + C content of 72.8% and consisted of 6,779 protein-coding genes. AntiSMASH analysis resulted in the identification of 29 biosynthetic gene clusters (BGCs) for secondary metabolites. Among them, 4 BGCs showed low similarity (28–67% of genes show similarity) to actinomycin, streptovaricin, and polyoxypeptin gene clusters, possibly attributed to antibacterial and anticancer activities observed. In addition, the complete biosynthetic pathways of plant-derived compounds, including daidzein and genistein were identified using genome mining and HPLC-DAD-MS analysis. These findings portray an exciting avenue for future characterization of promising secondary metabolites from mangrove endophytic
Journal Article
Diversity of microbial community and its metabolic potential for nitrogen and sulfur cycling in sediments of Phu Quoc island, Gulf of Thailand
2021
Although Phu Quoc island, Gulf of Thailand possesses diverse marine and coastal ecosystems, biodiversity and metabolic capability of microbial communities remain poorly investigated. The aim of our study was to evaluate the biodiversity and metabolic potential of sediment microbial communities in Phu Quoc island. The marine sediments were collected from three different areas and analyzed by using 16S rRNA gene-based amplicon approach. A total of 1,143,939 reads were clustered at a 97% sequence similarity into 8,331 unique operational taxonomic units, representing 52 phyla. Bacteria and archaea occupied averagely around 86% and 14%, respectively, of the total prokaryotic community. Proteobacteria, Planctomycetes, Chloroflexi, and Thaumarchaeota were the dominant phyla in all sediments, which were involved in nitrogen and sulfur metabolism. Sediments harboring of higher nitrogen sources were found to coincide with increased abundance of archaeal phylum Thaumarchaeota. Predictive functional analysis showed high abundance prokaryotic genes associated with nitrogen cycling including
nifA-Z
,
amoABC
,
nirA
,
narBIJ
,
napA
,
nxrAB
,
nrfA-K
,
nirBD
,
nirS
,
nirK
,
norB-Z
,
nlnA
,
ald
, and
ureA-J
, based on taxonomic groups detected by 16S rRNA sequencing. Although the key genes involved in sulfur cycling were found to be at low to undetectable levels, the other genes encoding for sulfur-related biological processes were present, suggesting that alternative pathways may be involved in sulfur cycling at our study site. In conclusion, our study for the first time shed light on diversity of microbial communities in Phu Quoc island.
Journal Article
Exploring omics strategies for drug discovery from Actinomycetota isolated from the marine ecosystem
by
Narsing Rao, Manik Prabhu
,
Sathish, Manda
,
Quach, Ngoc Tung
in
Actinobacteria
,
Antibiotics
,
Antimicrobial agents
2025
Marine Actinomycetota are prolific producers of diverse bioactive secondary metabolites, making them vital for drug discovery. Traditional cultivation and bioassay-guided isolation techniques often lead to the rediscovery of the same compounds, revealing the limitations of these traditional approaches and emphasizing the need for more advanced methods. The emergence of omics technologies such as genomics, metagenomics, transcriptomics, and metabolomics has dramatically enhanced the ability to investigate microorganisms by providing detailed insights into their biosynthetic gene clusters, metabolic pathways, and regulatory mechanisms. These comprehensive tools facilitate the discovery and functional analysis of new bioactive compounds by revealing the genetic blueprints underlying their biosynthesis. Omics and function-driven techniques like heterologous expression, analytical techniques (including high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy), and culture condition optimization have enabled access to previously silent or cryptic gene clusters, expanding the chemical diversity available for exploration. This review emphasizes the integration of omics-based insights with function-driven methodologies and innovative culture techniques, forming a holistic approach to unlock the extensive biosynthetic capabilities of marine Actinomycetota . Combining these strategies holds great promise for discovering new marine-derived compounds with potential therapeutic applications.
Journal Article
Distribution, cytotoxicity, and antioxidant activity of fungal endophytes isolated from Tsuga chinensis (Franch.) Pritz. in Ha Giang province, Vietnam
2022
Purpose
An endangered
Tsuga chinensis
(Franch.) Pritz. is widely used as a natural medicinal herb in many countries, but little has been reported on its culturable endophytic fungi capable of producing secondary metabolites applied in modern medicine and pharmacy. The present study aimed to evaluate the distribution of fungal endophytes and their cytotoxic and antioxidant properties.
Methods
This study used the surface sterilization method to isolate endophytic fungi which were then identified using morphological characteristics and ITS sequence analysis. The antimicrobial and cytotoxic potentials of fungal ethyl acetate extracts were evaluated by the minimum inhibitory concentration (MIC) and sulforhodamine B (SRB) assays, respectively. Paclitaxel-producing fungi were primarily screened using PCR-based molecular markers. Additionally, biochemical assays were used to reveal the antioxidant potencies of selected strains.
Results
A total of sixteen endophytic fungi that belonged to 7 known and 1 unknown genera were isolated from
T. chinensis
. The greatest number of endophytes was found in leaves (50%), followed by stems (31.3%) and roots (18.7%). Out of 16 fungal strains, 33.3% of fungal extracts showed significant antimicrobial activities against at least 4 pathogens with inhibition zones ranging from 11.0 ± 0.4 to 25.8 ± 0.6 mm. The most prominent cytotoxicity against A549 and MCF7 cell lines (IC
50
value < 92.4 μg/mL) was observed in
Penicillium
sp. SDF4,
Penicillium
sp. SDF5,
Aspergillus
sp. SDF8, and
Aspergillus
sp. SDF17. Out of three key genes (
dbat
,
bapt
,
ts
) involved in paclitaxel biosynthesis, strains SDF4, SDF8, and SDF17 gave one or two positive hits, holding the potential for producing the billion-dollar anticancer drug paclitaxel. Furthermore, four bioactive strains also displayed remarkable and wide-range antioxidant activity against DPPH, hydroxyl radical, and superoxide anion, which was in relation to the high content of flavonoids and polyphenols detected.
Conclusion
The present study exploited for the first time fungal endophytes from
T. chinensis
as a promising source for the discovery of new bioactive compounds or leads for the new drug candidates.
Journal Article
Substrate Influence on Enzymatic Activity in Cordyceps militaris for Health Applications
by
Van, Nguyen Minh Nhat
,
Nguyen, Vu Thi Hanh
,
Minh, Truong Ngoc
in
Adenosine
,
Amylases
,
Antioxidants
2024
Cordyceps militaris, well known for its therapeutic potential in managing type-2 diabetes through the inhibition of α-amylase and α-glucosidase enzymes, was the central focus of this research, which investigated the influence of various cultivation substrates on its enzymatic inhibitory properties and bioactive compound content. Previous studies have primarily focused on the general pharmacological benefits of C. militaris but have not thoroughly explored how different substrates affect its bioactive profile and enzyme inhibitory activities. This study aimed to evaluate the impact of substrate selection on the enzyme inhibition activities and the levels of bioactive compounds such as cordycepin and adenosine in C. militaris, demonstrating that substrate selection markedly affects both these enzymes’ inhibition activities and bioactive compound levels. Particularly, C. militaris fruiting bodies grown on Brihaspa atrostigmella showed the highest concentrations of cordycepin (2.932 mg/g) and adenosine (1.062 mg/g). This substrate also exhibited the most potent α-glucosidase inhibition with an IC50 value of 336.4 ± 16.0 µg/mL and the most effective α-amylase inhibition with an IC50 value of 504.6 ± 4.2 µg/mL. Conversely, C. militaris cultivated on the solid residues of Gryllus bimaculatus displayed the strongest xanthine oxidase (XOD) inhibition, with the lowest IC50 value of 415.7 ± 11.2 µg/mL. These findings highlight the critical role of substrate choice in enhancing the medicinal properties of C. militaris, suggesting that optimized cultivation can enhance the bioactive properties for more effective natural therapies for diabetes and other metabolic disorders. This study not only extends the understanding of C. militaris’ pharmacological potential but also illustrates its applicability in developing customized treatment options.
Journal Article
Genome-wide comparison deciphers lifestyle adaptation and glass biodeterioration property of Curvularia eragrostidis C52
2022
Glass biodeterioration by fungi has caused irreversible damage to valuable glass materials such as cultural heritages and optical devices. To date, knowledge about metabolic potential and genomic profile of biodeteriorative fungi is still scarce. Here, we report for the first time the whole genome sequence of
Curvularia eragrostidis
C52 that strongly degraded silica-based glasses coated with fluorine and hafnium, as expressed by the hyphal surface coverage of 46.16 ± 3.3% and reduced light transmission of 50.93 ± 1.45%. The genome of
C. eragrostidis
C52 is 36.9 Mb long with a GC content of 52.1% and contains 14,913 protein-coding genes, which is the largest genome ever recorded in the genus
Curvularia
. Phylogenomic analysis revealed
C. eragrostidis
C52 formed a distinct cluster with
Curvularia
sp. IFB-Z10 and was not evolved from compared genomes. Genome-wide comparison showed that strain C52 harbored significantly higher proportion of proteins involved in carbohydrate-active enzymes, peptidases, secreted proteins, and transcriptional factors, which may be potentially attributed to a lifestyle adaptation. Furthermore, 72 genes involved in the biosynthesis of 6 different organic acids were identified and expected to be crucial for the fungal survival in the glass environment. To form biofilm against stress, the fungal strain utilized 32 genes responsible for exopolysaccharide production. These findings will foster a better understanding of the biology of
C. eragrostidis
and the mechanisms behind fungal biodeterioration in the future.
Journal Article
Phenotypic features and analysis of genes supporting probiotic action unravel underlying perspectives of Bacillus velezensis VTX9 as a potential feed additive for swine
by
Ngo, Cao Cuong
,
Nguyen, Trung Nam
,
Nguyen, Van The
in
adhesion
,
Analysis
,
Animal feeding and feeds
2021
Purpose
To date, a total of 13 probiotic
Bacillus
species are considered as a Generally Recognized as Safe organism (GRAS) approved by the US Federal Food, Drug, and Cosmetic Act (FDCA), which are used for food and feed additives. However,
Bacillus velezensis
is not considered as a probiotic candidate in swine farming due to a lack of genetic basis of probiotic action-related traits. Therefore, the present study was undertaken to exploit the genetic basis underlying the probiotic traits of
B. velezensis
VTX9.
Methods
The genome sequencing of
B. velezensis
VTX9 was performed on a PacBio Sequel platform. The probiotic properties including biosafety, antioxidative capacity, and riboflavin and exopolysaccharide production were evaluated by using genotypic and phenotypic analysis. The secondary metabolite potentials were also predicted.
Results
Strain VTX9 isolated from swine feces proved some probiotic properties including resistance to 3 mM H
2
O
2
, 0.6 mM bile salt, low pH, and antipathogenic activity. The complete genome of
B. velezensis
VTX9 consists of a 3,985,800 bp chromosome that housed 3736 protein-coding genes and 5 plasmids with the size ranging from 7261 to 20,007 bp. Genome analysis revealed no functional genes encoding enterotoxins and transferable antibiotic resistance, which confirmed the safety of VTX9. A total of 82 genes involved in gastrointestinal stress tolerance were predicted, which has not been reported previously. The maximum production of riboflavin reached 769 ± 7.5 ng/ml in LB medium after 72 h, which was in agreement with the complete de novo riboflavin biosynthetic pathway exploited for the first time in the
B. velezensis
genome. Antagonistic activity against pathogenic bacteria was attributed to 10 secondary metabolites clusters. The presence of a large gene cluster involved in biosynthesis of exopolysaccharides underscored further the adhesion and biofilm-forming capabilities of VTX9 in swine intestines.
Conclusion
Our results revealed for the first time that
B. velezensis
VTX9 has the potential to be a probiotic candidate. The information provided here on the genome of
B. velezensis
VTX9 opens new opportunities for using
B. velezensis
as a feed additive for swine farming in the future.
Journal Article