Increasing production of spinosad in Saccharopolyspora spinosa by metabolic engineering.

Spinosad, a combination of spinosyn A and D produced by Saccharopolyspora spinosa, is a highly efficient pesticide. There has been a considerable interest in the improvement of spinosad production because of a low yield achieved by wild-type S. spinosa. In this study, we designed and constructed a pIBR-SPN vector. pIBR-SPN is an integrative vector that can be used to introduce foreign genes into the chromosome of S. spinosa. Different combinations of genes encoding forasamine and rhamnose were synthesized and used for the construction of different recombinant plasmids. The following recombinant strains were developed: S. spinosa pIBR-SPN (only the vector), S. spinosa pIBR-SPN F (forosamine genes), S. spinosa pIBR-SPN R (rhamnose genes), S. spinosa pIBR-SPN FR (forosamine and rhamnose genes), S. spinosa pIBR-SPN FRS (forosamine, rhamnose, and SAM [S-adenosyl-L-methionine synthetase] genes), and S. spinosa MUV pIBR-SPN FR. Among these recombinant strains, S. spinosa pIBR-SPN FR produced 1394 ± 163 mg/L spinosad, which was 13-fold higher than the wild-type. S. spinosa MUV pIBR-SPN FR produced 1897 (±129) mg/L spinosad, which was seven-fold higher than S. spinosa MUV and 17-fold higher than the wild-type strain.

A new species of Leptobrachella (Anura, Megophryidae) from Mount Pu Ta Leng, northwest Vietnam.

The Hoang Lien Range in northwest Vietnam is known to harbour five species of Leptobrachella, a specious genus of terrestrial frogs. We collected specimens of Leptobrachella from Mount Pu Ta Leng on the second highest peak in the Hoang Lien Range and use morphological and molecular data to show that this population represents a previously undescribed species which we name Leptobrachella graminicola sp. nov. after the abundance of calling males on sedge-like plants. This new species is closely related to L. bourreti but the new species is distinguished from L. bourreti and other congeneric species by a combination of the following characters: (1) a body size range of 23.124.6 mm in six adult males and 28.632.9 mm in five adult females; (2) skin on dorsum smooth, with many tubercles and lacking dermal ridges; (3) toes with rudimentary webbing and broad lateral fringes; (4) belly white with brown spots; (5) throat dark brown with light grey-brown flecks and spots; (6) a row of large white spots on the outer edge of the tarsus extending from the heel to the inner metatarsal tubercle, sometimes forming a long white stripe; and (7) a bicoloured iris. The new, high-elevation species is likely to be range-restricted and threatened by habitat loss and the activities of tourists.

Genome mining Streptomyces sp. KCTC 0041BP as a producer of dihydrochalcomycin.

Streptomyces sp. KCTC 0041BP, which was isolated from a soil sample in Cheolwon, Republic of Korea, is a dihydrochalcomycin producer. In this study, we obtained the genome of S. sp. KCTC 0041BP with 7.54 Mb genome size. antiSMASH and the dbCAN2 meta server predicted that the genome would contain 26 secondary metabolite biosynthetic gene clusters (BGCs) and 285 carbohydrate-active enzymes. Besides dihydrochalcomycin, 21 compounds were successfully identified from S. sp. KCTC 0041BP, and among them, the structure of 8 compounds were proven by high-resolution electrospray ionization mass spectrometry (HRESIMS) and nuclear magnetic resonance (NMR). The identification of chalcomycin analogs led to a better understanding of the biosynthetic pathway of dihydrochalcomycin/chalcomycin. From the analysis of cluster 2 and solvent selection, linearmycins were determined. Linearmycins showed antibacterial activity with both Gram-positive and Gram-negative bacteria and antifungal activity. One strain many compounds (OSMAC) strategy was applied to activate the salicylic acid production in this strain. A salicylic acid biosynthetic pathway was also predicted, but not by antiSMASH. These results showed that this strain can produce many useful compounds and potentially produce novel compounds with most secondary BGCs yet to be experimentally identified.

Identification and enhancing production of a novel macrolide compound in engineered Streptomyces peucetius.

Streptomyces peucetius produces doxorubicin and daunorubicin, which are important anticancer drugs. In this study, we activate peucemycin, a new antibacterial compound, using an OSMAC strategy. In general, bioactive compounds are produced in a higher amount at room temperature; however, in this study, we have demonstrated that a bioactive novel compound was successfully activated at a low temperature (18 °C) in S. peucetius DM07. Through LC-MS/MS, IR spectroscopy, and NMR analysis, we identified the structure of this compound as a γ-pyrone macrolide. This compound was found to be novel, thus named peucemycin. It is an unusual 14-membered macrocyclic γ-pyrone ring with cyclization. Also, peucemycin exhibits potential antibacterial activity and a suppressive effect on the viability of various cancer cell lines.

A description of the tadpole of the Critically Endangered Botsford's leaf-litter frog (Leptobrachella botsfordi) with comments on the distribution and conservation status of the species.

We describe the tadpole of the Botsford's leaf-litter frog Leptobrachella botsfordi, a species endemic to Mount Fansipan in northwest Vietnam, for the first time. Tadpoles of this species were found in steep, fast-flowing streams at elevations between 2500-2600 m asl. We also report a previously unknown locality for this species on Mount Fansipan, which increases the species' known Extent of Occurrence from 8 km2 to 36 km2. Our findings will inform subsequent conservation initiatives for this poorly known and highly threatened species.

The tadpoles of five Megophrys Horned frogs (Amphibia: Megophryidae) from the Hoang Lien Range, Vietnam.

Frogs in the genus Megophrys are an Asian radiation of stream-breeding frogs. The tadpoles of many Megophrys species are undescribed; those that are described are often dubiously allocated to species by association with post metamorphic specimens at collection sites and without supportive molecular data. We provide detailed descriptions of the larvae of five species of Megophrys from the Hoang Lien Range in northwest Vietnam: Megophrys fansipanensis, M. gigantica, M. hoanglienensis, M. jingdongensis and M. maosonensis. Tadpoles from different subgenera differ from each other via a combination of patternation in life, oral disc shape and tail morphology but given the small sample size, and limited number of species it is unlikely that these differences can be applied more widely to delineate subgenera. Morphological differences between tadpoles from species within the subgenus Panophrys were insufficient to clearly delineate all species. The ability to identify tadpoles is likely to advance our understanding of the frog fauna in mainland southeast Asia.

Validity of the International Physical Activity Questionnaire-Short Form for Application in Asian Countries: A Study in Vietnam.

This is the first study in the Asia-Pacific region to examine the criterion validity of the self-reported International Physical Activity Questionnaire-Short form (IPAQ-SF) using accelerometers, in terms of achieving the World Health Organization's (WHO) recommended physical activity guidelines for health benefits. Vietnamese adults aged 40-65 years (n = 240) wore an ActiGraph GT3X+ accelerometer for at least 5 days and completed the Vietnamese version of the IPAQ-SF. Correlations between IPAQ-SF and accelerometer-measured physical activity intensities varied from .087 to .232. Mean difference in moderate-vigorous physical activity was 0.699 min/day (95% limits: [-107, 109]). Agreement on the classification of achieving the WHO's physical activity guidelines was 69.16%. The IPAQ-SF identified 71.86% of adults who met the guidelines, whereas 56.09% of those not meeting the guidelines were classified correctly. The IPAQ-SF was found to have acceptable criterion validity and is a useful instrument to classify Vietnamese adults as achieving or not achieving the WHO's physical activity guidelines for health benefits.

Recent Advances in Strategies for Activation and Discovery/Characterization of Cryptic Biosynthetic Gene Clusters in Streptomyces.

Streptomyces spp. are prolific sources of valuable natural products (NPs) that are of great interest in pharmaceutical industries such as antibiotics, anticancer chemotherapeutics, immunosuppressants, etc. Approximately two-thirds of all known antibiotics are produced by actinomycetes, most predominantly by Streptomyces. Nevertheless, in recent years, the chances of the discovery of novel and bioactive compounds from Streptomyces have significantly declined. The major hindrance for obtaining such bioactive compounds from Streptomyces is that most of the compounds are not produced in significant titers, or the biosynthetic gene clusters (BGCs) are cryptic. The rapid development of genome sequencing has provided access to a tremendous number of NP-BGCs embedded in the microbial genomes. In addition, the studies of metabolomics provide a portfolio of entire metabolites produced from the strain of interest. Therefore, through the integrated approaches of different-omics techniques, the connection between gene expression and metabolism can be established. Hence, in this review we summarized recent advancements in strategies for activating cryptic BGCs in Streptomyces by utilizing diverse state-of-the-art techniques.

Streptomyces sp. VN1, a producer of diverse metabolites including non-natural furan-type anticancer compound.

Streptomyces sp. VN1 was isolated from the coastal region of Phu Yen Province (central Viet Nam). Morphological, physiological, and whole genome phylogenetic analyses suggested that strain Streptomyces sp. VN1 belonged to genus Streptomyces. Whole genome sequencing analysis showed its genome was 8,341,703 base pairs in length with GC content of 72.5%. Diverse metabolites, including cinnamamide, spirotetronate antibiotic lobophorin A, diketopiperazines cyclo-L-proline-L-tyrosine, and a unique furan-type compound were isolated from Streptomyces sp. VN1. Structures of these compounds were studied by HR-Q-TOF ESI/MS/MS and 2D NMR analyses. Bioassay-guided purification yielded a furan-type compound which exhibited in vitro anticancer activity against AGS, HCT116, A375M, U87MG, and A549 cell lines with IC50 values of 40.5, 123.7, 84.67, 50, and 58.64 µM, respectively. In silico genome analysis of the isolated Streptomyces sp. VN1 contained 34 gene clusters responsible for the biosynthesis of known and/or novel secondary metabolites, including different types of terpene, T1PKS, T2PKS, T3PKS, NRPS, and hybrid PKS-NRPS. Genome mining with HR-Q-TOF ESI/MS/MS analysis of the crude extract confirmed the biosynthesis of lobophorin analogs. This study indicates that Streptomyces sp. VN1 is a promising strain for biosynthesis of novel natural products.

Exploration of cryptic organic photosensitive compound as Zincphyrin IV in Streptomyces venezuelae ATCC 15439.

Zincphyrin IV is a potential organic photosensitizer which is of significant interest for applications in biomedicine, materials science, agriculture (as insecticide), and chemistry. Most studies on Zincphyrin are focused on Zincphyrin III while biosynthesis and application of Zincphyrin IV is comparatively less explored. In this study, we explored Zincphyrin IV production in Streptomyces venezuelae ATCC 15439 through combination of morphology engineering and "One strain many compounds" approach. The morphology engineering followed by change in culture medium led to activation of cryptic Zincphyrin IV biosynthetic pathway in S. venezuelae with subsequent detection of Zincphyrin IV. Morphology engineering applied in S. venezuelae increased the biomass from 7.17 to 10.5 mg/mL after 48 h of culture. Moreover, morphology of engineered strain examined by SEM showed reduced branching and fragmentation of mycelia. The distinct change in color of culture broth visually demonstrated the activation of the cryptic biosynthetic pathway in S. venezuelae. The production of Zincphyrin IV was found to be initiated after overexpression ssgA, resulting in the increase in titer from 4.21 to 7.54 µg/mL. Furthermore, Zincphyrin IV demonstrated photodynamic antibacterial activity against Bacillus subtilis and photodynamic anticancer activity against human ovarian carcinoma cell lines.

Objectively Measured Physical Activity of Vietnamese Adults With Type 2 Diabetes: Opportunities to Intervene.

OBJECTIVES: To objectively determine and compare the physical activity (PA) levels of adults newly diagnosed with type 2 diabetes (T2D) and adults without T2D in Vietnam using an accelerometer. METHODS: A total of 120 participants with newly diagnosed T2D and 120 adults without T2D were recruited from a large hospital in Hanoi, the capital city of Vietnam. All participants wore an ActiGraph GT3X accelerometer for at least 5 days, including 1 weekend day. Freedson cut-off points were used to estimate different intensities of PA. In addition, comparisons between groups were made with respect to achieving the World Health Organization (WHO) and International Diabetes Federation (IDF) recommended PA guidelines. RESULTS: Men with T2D had significantly lower levels of PA than men without T2D. The respective multivariable-adjusted mean values of daily step count, daily light-intensity, moderate-intensity, and moderate-to-vigorous-intensity PA were approximately 14%, 19%, and 22% lower in the men with T2D than in their non-T2D counterparts. However, women with T2D accumulated a greater number of steps per day than women without T2D. Only 59.2% of the adults with T2D met the minimum recommended level of PA (WHO and IDF), compared to 74.2% of adults without T2D (p<0.05). After adjusting for potential confounders, participants with T2D experienced 50.0% significantly lower odds of achieving PA recommendations. CONCLUSIONS: Vietnamese men with T2D were less physically active than those without T2D, and adults with T2D were less likely to meet PA guidelines. The results suggest a need for integrating PA into the self-management of this chronic condition.

Two new and potentially highly threatened Megophrys Horned frogs (Amphibia: Megophryidae) from Indochina's highest mountains.

Megophrys are a group of morphologically conserved, primarily forest-dependent frogs known to harbour cryptic species diversity. In this study, we examined populations of small-sized Megophrys from mid- and high elevation locations in the Hoang Lien Range, northern Vietnam. On the basis of morphological, molecular and bioacoustic data, individuals of these populations differed from all species of Megophrys known from mainland Southeast Asia north of the Isthmus of Kra and from neighbouring provinces in China. Further, the newly collected specimens formed two distinct species-level groups. We herein describe two new species, Megophrys fansipanensis sp. nov. and Megophrys hoanglienensis sp. nov. Both new species are range restricted and likely to be highly threatened by habitat degradation. These discoveries highlight the importance of the Hoang Lien Range for Vietnam's amphibian diversity.

Habitual tea drinking associated with a lower risk of type 2 diabetes in Vietnamese adults.

BACKGROUND AND OBJECTIVES: The association between tea consumption and type 2 diabetes risk remains inconsistent in Asian populations. This case-control study investigated the association between habitual tea consumption and the risk of type 2 diabetes among Vietnamese adults. METHODS AND STUDY DESIGN: A hospital-based case-control study was conducted during 2013-2015 in Vietnam. A total of 599 newly diagnosed diabetic cases (aged 40-65 years) and 599 hospital-based controls, frequency matched by age and sex, were recruited. Information about frequency, quantity, and duration of tea drinking, together with demographics, habitual diet and lifestyle characteristics, was obtained from direct interviews using a validated and reliable questionnaire. Unconditional logistic regression analyses were performed to assess the association between different metrics of tea consumption and the type 2 diabetes risk. RESULTS: Control subjects reported higher tea consumption levels than the cases in terms of duration, frequency, and quantity of tea drunk. After accounting for confounding factors, increasing tea consumption was found to be associated with a reduced risk of type 2 diabetes; the adjusted odds ratio (95% confidence interval) was 0.66 (0.49, 0.89) for participants drinking >2 cups/day, relative to those drinking <1 cup/day. Significant inverse dose-response relationships were also observed for average number of cups consumed daily and years of tea drinking (p<0.01). CONCLUSIONS: Habitual tea consumption is associated with a reduced risk of type 2 diabetes among Vietnamese adults.

The Vietnamese population of Megophrys kuatunensis (Amphibia: Megophryidae) represents a new species of Asian horned frog from Vietnam and southern China.

The Asian frog genus Megophrys is a diverse group of morphologically conserved, forest-dwelling frogs. The genus harbours highly localised species diversification and new species continue to be described on a regular basis. We examined the taxonomic status of a population of Megophrys frogs from the Hoang Lien Range in northern Vietnam and southern China previously identified as M. kuatunensis (subgenus Panophrys). Preliminary phylogenetic analyses using a fragment of 16S rDNA places the species in question within the Megophrys (subgenus Panophrys) species group, a primarily Chinese radiation within the genus. On the basis of morphological, molecular and bioacoustic data, we conclude that this population does not represent M. kuatunensis, or any known species in the genus. We herein describe this species of Megophrys as new. Known only from Sa Pa District, Lao Cai Province in Vietnam and Jinping County, Yunnan Province in China, the new species is likely to be threatened by ongoing deforestation in the region. We provide an updated species description of M. kuatunensis based on type specimens, and suggest that M. kuatunensis is likely to be restricted to eastern China.