Search

Abstract Previous studies have reported the functional role, biochemical features and synthesis pathway of podophyllotoxin (PTOX) in plants. In this study, we employed combined morphological and molecular techniques to identify an endophytic fungus and extract PTOX derivatives. Based on the analysis of ITS sequences and the phylogenetic tree, the isolate was classified as Penicillium herquei HGN12.1C, with a sequence identity of 98.58%. Morphologically, the HGN12.1C strain exhibits white colonies, short‐branched mycelia and densely packed hyphae. Using PacBio sequencing at an average read depth of 195×, we obtained a high‐quality genome for the HGN12.1C strain, which is 34.9 Mb in size, containing eight chromosomes, one mitochondrial genome and a GC content of 46.5%. Genome analysis revealed 10 genes potentially involved in PTOX biosynthesis. These genes include VdtD, Pinoresinollariciresinol reductase (PLR), Secoisolariciresinol dehydrogenase (SDH), CYP719A23, CYP71BE54, O‐methyltransferase 1 (OMT1), O‐methyltransferase 3 (OMT3), 2‐ODD, CYP71CU and CYP82D61. Notably, the VdtD gene in fungi shares functional similarities with the DIR gene found in plants. Additionally, we identified peltatin, a PTOX derivative, in the HGN12.1C extract. Docking analysis suggests a potential role for the 2‐ODD enzyme in converting yatein to deoxypodophyllotoxin. These findings offer invaluable insights into the synthesis mechanism of PTOX in fungi, shedding light on the relationship between host plants and endophytes.

Amentotaxus yunnanensis H.L.Li is a threatened conifer distributed only in China, Laos, and Vietnam, whose fungal endophytes have not been exploited yet. The aims of this study were to screen and characterize antioxidant metabolites from endophytic fungi obtained from A. yunnanensis. Using the surface sterilization method, sixteen endophytic fungi were isolated from A. yunnanensis and classified into seven genera including Fusarium, Penicillium, Aspergillus, Diaporthe, Neopestalotiopsis, Purpureocillium, and Simplicillium through the analysis of Internal Transcribed Spacer (ITS) gene sequences. Among the ethyl acetate crude extracts, Fusarium foetens AQF6 contained the highest amount of polyphenol (117.76 ± 0.94 mg gallic acid equivalent/g) and flavonoid (169.01 ± 2.09 mg quercetin equivalent/g). Importantly, 400 µg/mL AQF6 extract exhibited 95.75 ± 1.1% and 85.66 ± 1.91% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging activities, respectively. Chemical investigation led to the isolation and identification of a new bisabolane-type sesquiterpene fusafoetriol (FUS) and 14 known compounds, among which six pure compounds showed free-radical scavenging activity against DPPH and hydroxyl radicals. Under H2O2 stress, the yeast model Saccharomyces cerevisiae treated with 4 mM FUS showed 43.31% increase in viability. FUS has the potential to be applied in nutraceutical, pharmaceutical and food technological applications. Thus, this is the first report demonstrating the presence of endophytic fungi inhabiting A. yunnanensis and their potential as a prolific source of antioxidant metabolites.

Background Mitochondrial DNA (mtDNA) analysis has been used in forensics and requires well-established population databases for statistical interpretations. However, high-quality mtDNA data from Vietnamese population samples have been limited. Aim To examine the mtDNA sequences and haplogroup compositions of a Vietnamese population to provide an mtDNA dataset that can further be used to construct a Vietnamese-specific reference database. Subjects and methods A total of 173 Vietnamese individuals were analysed for two hypervariable regions (HVI and HVII) of mtDNA. Forensic parameters were calculated and haplogroup assignment was performed based on the resulting mtDNA haplotypes. Genetic relationships between the Vietnamese and other Asian populations were investigated through principal component analysis (PCA) and pairwise Fst. Results The Vietnamese population sample consisted of 145 different haplotypes with a random match probability of 0.96%, a power of discrimination of 0.9904, and a haplotype diversity of 0.9962. The samples were assigned to 83 haplogroups that were commonly reported in Asia. PCA and pairwise Fst revealed close relationships of the Vietnamese population with other Asian populations, especially with populations in proximity. Conclusion The results from this study can contribute to the current genetic information content as a supplementary mtDNA reference dataset for forensic investigations and phylogenetic research.

Abstract 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 (IC50 value

Abstract 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.

Abstract Penicillium oxalicumP. oxalicumIxora chinensisP. oxalicum

Abstract 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 H2O2, 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.

Abstract Adrinandra megaphylla Hu is a medicinal plant belonging to the Adrinandra genus, which is well-known for its potential health benefits due to its bioactive compounds. This study aimed to assemble and annotate the chloroplast genome of A. megaphylla as well as compare it with previously published cp genomes within the Adrinandra genus. The chloroplast genome was reconstructed using de novo and reference-based assembly of paired-end reads generated by long-read sequencing of total genomic DNA. The size of the chloroplast genome was 156,298 bp, comprised a large single-copy (LSC) region of 85,688 bp, a small single-copy (SSC) region of 18,424 bp, and a pair of inverted repeats (IRa and IRb) of 26,093 bp each; and a total of 51 SSRs and 48 repeat structures were detected. The chloroplast genome includes a total of 131 functional genes, containing 86 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The A. megaphylla chloroplast genome indicated that gene content and structure are highly conserved. The phylogenetic reconstruction using complete cp sequences, matK and trnL genes from Pentaphylacaceae species exhibited a genetic relationship. Among them, matK sequence is a better candidate for phylogenetic resolution. This study is the first report for the chloroplast genome of the A. megaphylla.

Abstract The genus Paramignya (Rutaceae) comprises about 30 species typically distributing in tropical Asia. Like other genera of the family Rutaceae, the significant variation in the morphology of Paramignya species makes the taxonomic study and accurate identification become difficult. In Vietnam, Paramignya species have been mostly found in Khanh Hoa and Lam Dong provinces and used as traditional medicines. Recently, Paramignya trimera, a species of the genus Paramignya with local name “Xao tam phan” has been drawn attention and intensively exploited to treat liver diseases and cancers. However, the significant variations in the morphology and different local names of P. trimera have caused confusion and difficulty in the accurate identification and application of this plant for medicine. In this study, the combination of both morphological and DNA sequence data has effectively supported the taxonomic identification of P. trimera and some relatives collected in Khanh Hoa and Lam Dong provinces. The comparison of the morphology and analysis of the phylogenetic trees suggested that there was a significant variation of P. trimera. In addition, some accessions of P. trimera with morphological characteristics similar and Atalantia buxifolia were likely the intergeneric hybrids between the two species. Analysis of genetic variation, interspecific and intraspecific distances using ITS, matK and rbcL sequences shown that P. trimera was closely related to A. buxifolia, Severinia monophylla and Luvunga scandens. In addition, matK sequences represented as the effective candidate DNA barcode to identify and distinguish Paramignya species from others of the family Rutaceae.

Nematode damage to coffee poses a serious threat to coffee production all over the world, including Vietnam. Accordingly, the nematode community composition could be a reliable indicator of ecological shifts that affect coffee plants' health. Here, we analysed the nematode communities in the rhizosphere of a monoculture Robusta coffee plantation in Dak Lak of the Central Highlands, Vietnam. We found changes in the community composition of nematodes in an age gradient of replanting coffee plants and revealed distinct patterns of nematode distribution in the soils of healthy and diseased plant groups. Further analyses indicate the impact of intensive farming and inefficient nematode controls, which caused disturbances and a gradual decrease of the nematode fauna diversity in the plantation soil. These results can add to a complete prediction model for plant fitness using nematode community composition.

Abstract Fluorescent nanodiamond (FND) has been used for long-term cell labeling and in vivo cell tracking because they have good at photostability and biocompatibility. In this study, we evaluate the effect of fluorescent nanodiamond labeling on in vitro culture and differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs) into hepatocyte-like cells (HLCs). For hepatic differentiation of hUCMSCs, cells were induced with human hepatocyte growth factor, nicotinamide and Dexamethasone. FND was supplied in two experimental groups with 20 μg/mL and 100 μg/mL in 2 hours. The cell was assessed for FND uptake by laser scan microscopy and flow cytometry methods. The effect of FND on hUCMSCs was evaluated by the cell viability and growth assays as well as the differentiation throughout of morphology alterations or gene expression of anfa-fetoprotein, albumin, and hepatocyte nuclear factor 4α. The results showed that the labeling of hUCMSCs is efficient and easy and there was significant cellular uptake of FND. We did not observe any negative impacts of FND to the cell viability and growth. FND can be utilized for the long-term labeling and tracking of hUCSCs and HLCs in vivo studies.

Exopolysaccharides (EPSs) produced by Bacillus species have recently emerged as promising commercial antioxidants in various industries, such as pharmaceutics and biomedicine. However, little is known about EPS production and function from Bacillus velezensis so far. In the present study, the effect of sugar sources on EPS production by B. velezensis VTX20 and the genetic biosynthesis, characteristics, and antioxidant activity of the resulting EPS were evaluated. The strain VTX20 produced the maximum EPS yield of 75.5 ± 4.8 g/L from an initial 200 g/L of sucrose after a 48-h cultivation. Through genomic analysis, ls-levB operon was found, for the first time, to be responsible for the levan-type EPS production in B. velezensis. Biochemical and structural characterization further confirmed the majority of levan, followed by an extremely low level of dextran biopolymer. The water solubility index and water holding capacity of the EPSs were 81.9 ± 3.4% and 100.2 ± 3.4%, respectively. In vitro antioxidant activity analyses showed strong scavenging activity for 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical values of 40.1–64.0% and 16.0–40%, respectively. These findings shed light on the EPS biosynthesis of B. velezensis at both structural and genetic levels and the potential application of EPS as a natural antioxidant for pharmaceutical and biomedical industries.

Many Vietnamese citizens have been and continue to be inadvertently exposed to dioxins and dioxin-like compounds deposited in the country during the Vietnam War. Dioxins may be involved in the pathogenesis of inflammatory diseases in part via by affecting expression of aryl hydrocarbon receptor (Ahr) and inflammatory cytokines in animal models. As the role of the Ahr in dioxin-exposed people is not well defined, a study was conducted to examine gene expression levels of Ahr, inflammatory cytokines, and the incidence of diseases in dioxin-exposed citizens who had/still resided near a heavily dioxin-contaminated area in Vietnam. Whole blood from citizens at/around Da Nang airbase and control individuals living in unsprayed areas was collected. Serum levels of dioxins were analyzed by using a dioxins-responsive chemical-activated luciferase gene expression bioassay. Gene expression of Ahr, interleukin (IL)-1β, TNFα, IL-6, and IL-22 in whole blood was examined by quantitative real-time PCR. The results showed levels of dioxins and expression of Ahr, IL-1β, TNFα, and IL-6 were up-regulated while IL-22 expression was down-regulated in dioxin-exposed people. Various disease incidences in the study subjects was also examined. Interestingly, the incidence of rheumatoid arthritis (RA) in these individuals was increased compared to the estimated prevalence of this disease in the general Vietnamese population. Analyses also showed that expression levels of Ahr correlated to those of IL-6 and IL-22 in the dioxin-exposed people. Taken together, dioxins might be involved in an up-regulated expression of Ahr that might possibly relate to changes in level of inflammatory cytokines and, ultimately, in the incidence of select diseases in residents of Vietnam who had/continue to live near a dioxins-contaminated site.

The present study aimed to evaluate the synergistic effects of the crude ethyl acetate extract (CEAE) from endophytic actinomycete MPT42 and essential oil (EO) of the same host plant Litsea cubeba. The isolate MPT42, exhibiting broad-spectrum antimicrobial activities and harboring all three antibiotic-related biosynthetic genes pks-I, pks-II, and nrps, was identified as Streptomycete griseorubens based on an analysis of the morphology, physiology, and 16S rDNA sequence. Minimum inhibitory concentrations (MICs) and the fractional inhibitory concentration index were used to estimate the synergistic effects of various combined ratios between CEAE or antibiotics (erythromycin, vancomycin) and EO toward 13 microbial strains including pathogens. L. cubeba fruit EO, showing the main chemical constituents of 36.0% citral, 29.6% carveol, and 20.5% limonene, revealed an active-low against tested microbes (MICs ≥ 600 μg/mL). The CEAE of S. griseorubens culture exhibited moderate−strong antimicrobial activities against microbes (MICs = 80−600 μg/mL). Analysis of the mechanism of action of EO on Escherichia coli ATCC 25922 found that bacterial cells were dead after 7 h of the EO treatment at 1 MIC (5.5 mg/mL), where 62% cells were permeabilized after 2 h and 3% of them were filament (length ≥ 6 μm). Combinations of CEAE, erythromycin, or vancomycin with EO led to significant synergistic antimicrobial effects against microbes with 4−16 fold reduction in MIC values when compared to their single use. Interestingly, the vancomycin−EO combinations exhibited a strong synergistic effect against five Gram-negative bacterial species. This could assume that the synergy was possibly due to increasing the cell membrane permeability by the EO acting on the bacterial cells, which allows the uptake and diffusion of antimicrobial substances inside the cell easily. These findings in the present study therefore propose a possible alternative to combat the emergence of multidrug-resistant microbes in veterinary and clinics.

In Vietnam, a great number of toxic substances, including carcinogens and procarcinogens, from industrial and agricultural activities, food production, and healthcare services are daily released into the environment. In the present study, we report the development of novel yeast-based biosensor systems to determine both genotoxic carcinogens and procarcinogens by cotransformation with two plasmids. One plasmid is carrying human CPR and CYP (CYP3A4, CYP2B6, or CYP2D6) genes, while the other contains the RAD54-GFP reporter construct. The three resulting coexpression systems bearing both CPR-CYP and RAD54-GFP expression cassettes were designated as CYP3A4/CYP2B6/CYP2D6 + RAD54 systems, respectively and used to detect and evaluate the genotoxic potential of carcinogens and procarcinogens by selective activation and induction of both CPR-CYP and RAD54-GFP expression cassettes in response to DNA damage. Procarcinogens were shown to be predominantly, moderately or not bioactivated by one of the CYP enzymes and thus selectively detected by the specific coexpression system. Aflatoxin B1 and benzo(a)pyrene were predominantly detected by the CYP3A4 + RAD54 system, while N-nitrosodimethylamine only moderately activated the CYP2B6 + RAD54 reporter system and none of them was identified by the CYP2D6 + RAD54 system. In contrast, the genotoxic carcinogen, methyl methanesulfonate, was detected by all systems. Our yeast-reporter system can be performed in 384-well microplates to provide efficient genotoxicity testing to identify various carcinogenic compounds and reduce chemical consumption to about 53% as compared with existing 96-well genotoxicity bioassays. In association with a liquid handling robot, this platform enables rapid, cost-effective, and high-throughput screening of numerous analytes in a fully automated and continuous manner without the need for user interaction.

Camptothecin (CPT) is an important alkaloid used for anticancer treatment. It is mainly produced by two endangered and overharvested Camptotheca acuminata and Nothapodytes nimmoniana plants. Endophytic fungi are promising alternative sources for CPT production. In the present study, fungi residing within explants of Ixora chinensis were isolated and their CPT-producing capability of their endophytes was verified via thin-layer chromatography, high-performance liquid chromatography, liquid chromatography/high resolution mass spectrometry, and nuclear magnetic resonance analyses and compared with standards. In addition, MTT and sulforhodamine B assays were selected to test the anticancer effect. The endophytic fungi collection of 62 isolates were assigned to 11 genera, with four common genera (Diaporthe, Phyllosticta, Colletotrichum, and Phomopsis) and seven less common genera (Penicillium, Botryosphaeria, Fusarium, Pestalotiopsis, Aspergillus, and Didymella). Moreover, the anticancer activity of extracts was assessed against human lung carcinoma (A549). Among eight potential extracts, only Penicillium sp. I3R2 was found to be a source of CPT, while the remaining seven extracts have not been discovered potential secondary compounds. Thus, other prominent endophytic fungi might be potential candidates of phytochemicals with anticancer properties. [ABSTRACT FROM AUTHOR]

Rice is the staple food for half of the world's population. Phosphorus is an essential element for rice plant growth, development and production; however, the availability of soluble phosphate for plant uptake is often limited due to the binding with cation in different pH environments. Therefore, the development of rice plant varieties, which can grow well under a limited phosphate environment, is an urgent need for agricultural development for biotechnology. This study reported two contrasting rice varieties' biochemical and molecular adaptation toward a low phosphate medium. The results show that the response of these two varieties is genotypedependent. We observed a higher phosphate use efficiency in the low-Pi-sensitive G299 rice variety than in the low-Pi-tolerant G22 rice variety. Moreover, the expression of five out of six investigated genes relating to the low Pi responsive pathway, including two purple acid phosphatase (PAP), phosphate starvation response 2 (PHR2), SPX (SYG1/PHO81/XPR1) domain-containing gene, phosphate transcription factor 1 (PTF1) and phosphate 1 (PHO1) were significantly higher in the low-Pi-sensitive accession than in the tolerant genotype. Impressively, 214 times more expression of the PHO1 was observed in the leaves of the G299 variety than in the G22 variety, followed by SPX, PTF1, PHR2, and PAP21 genes. Similarly, the PHO1 was induced at the highest level in the roots of the G299 variety, followed by PAP21, PHR2, PTF1, and SPX1 genes. These findings supply further information for elucidation of the mechanism behind the response of rice plants to low phosphate medium and the development of the low Pi nutrient happy rice varieties. [ABSTRACT FROM AUTHOR]