Isolation of Streptomyces inhibiting multiple-phytopathogenic fungi and characterization of lucensomycin biosynthetic gene cluster.

Soil microorganisms with diverse bioactive compounds such as Streptomyces are appreciated as valuable resources for the discovery of eco-friendly fungicides. This study isolated a novel Streptomyces from soil samples collected in the organic green tea fields in South Korea. The isolation process involved antifungal activity screening around 2400 culture extracts, revealing a strain designated as S.

Comparative study on gradient-free optimization methods for inverse source-term estimation of radioactive dispersion from nuclear accidents.

In this study, we rigorously assess the performance of three gradient-free optimization algorithms-Ensemble Kalman Inversion (EKI), Particle Swarm Optimization (PSO), and Genetic Algorithm (GA)-for estimating source terms in diverse radionuclide release scenarios. Our analysis encompasses both single and multiple sources with varying radionuclide compositions, delving into the influence of decay constants and radioactivity on source estimation accuracy. Although estimating a single radionuclide from a single source exhibits outstanding results, estimating multiple radionuclides from a single source proves more arduous due to the limited information available for discerning gamma dose rates.

CRISPR-Driven Genome Engineering for Chorismate- and Anthranilate-Accumulating Cell Factories.

In this study, we aimed to enhance the accumulation of chorismate (CHR) and anthranilate (ANT), key intermediates in the shikimate pathway, by modifying a shikimate over-producing recombinant strain of [19]. To achieve this, we utilized a CRISPR-driven genome engineering approach to compensate for the deletion of shikimate kinase (AroK) as well as ANT synthases (TrpEG) and ANT phosphoribosyltransferase (TrpD). In addition, we inhibited the CHR metabolic pathway to induce CHR accumulation.

Utilizing EEG and fNIRS for the detection of sleep-deprivation-induced fatigue and its inhibition using colored light stimulation.

Drowsy driving is a common, but underestimated phenomenon in terms of associated risks as it often results in crashes causing fatalities and serious injuries. It is a challenging task to alert or reduce the driver's drowsy state using non-invasive techniques. In this study, a drowsiness reduction strategy has been developed and analyzed using exposure to different light colors and recording the corresponding electrical and biological brain activities.

Engineered cell factory for anthranilate over-production.

Anthranilate is a key platform chemical in high demand for synthesizing food ingredients, dyes, perfumes, crop protection compounds, pharmaceuticals, and plastics. Microbial-based anthranilate production strategies have been developed to overcome the unstable and expensive supply of anthranilate chemical synthesis from non-renewable resources. Despite the reports of anthranilate biosynthesis in several engineered cells, the anthranilate production yield is still unsatisfactory.

BAC cloning and heterologous expression of a giant biosynthetic gene cluster encoding antifungal neotetrafibricin in .

Polyene natural products including nystatin A1, amphotericin B, ECO-02301, and mediomycin belong to a large family of valuable antifungal polyketide compounds typically produced by soil actinomycetes. A previous study (Park et al., Front.

Isolation and Characterization of Engineered Nucleoside Deoxyribosyltransferase with Enhanced Activity Toward 2'-Fluoro-2'-Deoxynucleoside.

Nucleoside deoxyribosyltransferase (NDT) is an enzyme that replaces the purine or pyrimidine base of 2'-deoxyribonucleoside. This enzyme is generally used in the nucleotide salvage pathway in vivo and synthesizes many nucleoside analogs in vitro for various biotechnological purposes. Since NDT is known to exhibit relatively low reactivity toward nucleoside analogs such as 2'-fluoro-2'-deoxynucleoside, it is necessary to develop an enhanced NDT mutant enzyme suitable for nucleoside analogs.

BAC Cloning of a Large-Sized Biosynthetic Gene Cluster of NPP B1, a Potential SARS-CoV-2 RdRp Inhibitor.

As valuable antibiotics, microbial natural products have been in use for decades in various fields. Among them are polyene compounds including nystatin, amphotericin, and nystatin-like polyenes (NPPs). Polyene macrolides are known to possess various biological effects, such as antifungal and antiviral activities.

Shikimate Metabolic Pathway Engineering in .

Shikimate is a key high-demand metabolite for synthesizing valuable antiviral drugs, such as the anti-influenza drug, oseltamivir (Tamiflu). Microbial-based strategies for shikimate production have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. In this study, a microbial cell factory using was designed to overproduce shikimate in a fed-batch culture system.

Screening and Isolation of a Novel Polyene-Producing Strain Inhibiting Phytopathogenic Fungi in the Soil Environment.

Microbial-based eco-friendly biological substances are needed to protect crops from phytopathogenic fungi and replace toxic chemical fungicides that cause serious environmental issues. This study screened for soil antifungal strains, which produce rich, diverse, and valuable bioactive metabolites in the soil environment. Bioassay-based antifungal screening of approximately 2,400 strains led to the isolation of 149 strains as tentative antifungal producers.

Artificial cell factory design for shikimate production in Escherichia coli.

Shikimate is a key intermediate in high demand for synthesizing valuable antiviral drugs, such as the anti-influenza drug and oseltamivir (Tamiflu®). Microbial-based shikimate production strategies have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. Although shikimate biosynthesis has been reported in several engineered bacterial species, the shikimate production yield is still unsatisfactory.

WblA, a global regulator of antibiotic biosynthesis in Streptomyces.

Streptomyces species are soil-dwelling bacteria that produce vast numbers of pharmaceutically valuable secondary metabolites (SMs), such as antibiotics, immunosuppressants, antiviral, and anticancer drugs. On the other hand, the biosynthesis of most SMs remains very low due to tightly controlled regulatory networks. Both global and pathway-specific regulators are involved in the regulation of a specific SM biosynthesis in various Streptomyces species.

Recent Advances of Actinomycetes.

The discovery and development of actinomycete secondary metabolites (ASMs) have played pivotal roles in the fields of human medicine and its related biotechnology sectors over the past several decades [...

Recent advances in heterologous expression of natural product biosynthetic gene clusters in Streptomyces hosts.

The heterologous expression of natural product biosynthetic gene clusters (BGCs) has traditionally been used as a genetic platform to link various natural product chemotypes to their corresponding genotypes. In recent years, heterologous expression has played an increasing role in natural products research with the advances in sequencing technologies and bioinformatics tools that allow for the rapid and systematic identification of known and cryptic BGCs from a large number of microbial genome sequences. The advances in synthetic biology have also facilitated the process of heterologous expression by providing tools for rapid cloning and engineering of BGCs to improve production yield or to activate silent BGCs.

Recent Advances in Microbial Production of -Muconic Acid.

-Muconic acid (MA) is a valuable C6 dicarboxylic acid platform chemical that is used as a starting material for the production of various valuable polymers and drugs, including adipic acid and terephthalic acid. As an alternative to traditional chemical processes, bio-based MA production has progressed to the establishment of de novo MA pathways in several microorganisms, such as , , , and . Redesign of the metabolic pathway, intermediate flux control, and culture process optimization were all pursued to maximize the microbial MA production yield.

Structure-guided manipulation of the regioselectivity of the cyclosporine A hydroxylase CYP-sb21 from .

The cytochrome P450 enzyme CYP-sb21 from the rare actinomycete is capable of hydroxylating the immunosuppressive drug molecule cyclosporine A (CsA) primarily at the 4th N-methyl leucine (MeLeu), giving rise to -hydroxy--methyl-l-Leu-CsA (CsA-4-OH). This oxidative modification of CsA leads to dramatically reduced immunosuppressive activity while retaining the hair growth-promoting side-effect, thus demonstrating great application potential in both pharmaceutical and cosmetic industries. However, this P450 enzyme also hydroxylates CsA at the unwanted position of the 9th -methyl leucine (MeLeu), indicating that the regioselectivity needs to be improved for the development of CsA-4-OH into a commercial hair growth stimulator.

Stimulated Biosynthesis of an C10-Deoxy Heptaene NPP B2 Regulatory Genes Overexpression in .

Polyene macrolides, such as nystatin A1, amphotericin B, and NPP A1, belong to a large family of valuable antifungal polyketide compounds that are typically produced by soil actinomycetes. Previously, NPP B1, a novel NPP A1 derivative harboring a heptaene core structure, was generated by introducing two amino acid substitutions in the putative NADPH-binding motif of the enoyl reductase domain in module 5 of the NPP A1 polyketide synthase in . This derivative showed superior antifungal activity to NPP A1.

Heterologous Expression of Daptomycin Biosynthetic Gene Cluster Via Artificial Chromosome Vector System.

The heterologous expression of the natural product (NP) biosynthetic gene cluster (BGC) has become an attractive strategy for the activation, titer improvement, and refactoring of valuable and cryptic NP BGCs. Previously, a artificial chromosomal vector system, pSBAC, was applied successfully to the precise cloning of large-sized polyketide BGCs, including immunosuppressant tautomycetin and antibiotic pikromycin, which led to stable and comparable production in several heterologous hosts. To further validate the pSBAC system as a generally applicable heterologous expression system, the daptomycin BGC of was cloned and expressed heterologously in a model cell factory.

Cell Factory Design and Culture Process Optimization for Dehydroshikimate Biosynthesis in .

3-Dehydroshikimate (DHS) is a useful starting metabolite for the biosynthesis of muconic acid (MA) and shikimic acid (SA), which are precursors of various valuable polymers and drugs. Although DHS biosynthesis has been previously reported in several bacteria, the engineered strains were far from satisfactory, due to their low DHS titers. Here, we created an engineered cell factory to produce a high titer of DHS as well as an efficient system for the conversion DHS into MA.

Pseudonocardia strain improvement for stimulation of the di-sugar heptaene Nystatin-like Pseudonocardia polyene B1 biosynthesis.

Pseudonocardia autotrophica was previously identified to produce a toxicity-reduced and solubility-improved disaccharide-containing anti-fungal compound belonging to the tetraene-family, Nystatin-like Pseudonocardia Polyene A1 (NPP A1). Subsequently NPP B1, a novel derivative harboring a heptaene core structure, was produced by a pathway-engineered Pseudonocardia strain through inactivation of the specific enoly reductase gene domain in the NPP biosynthetic gene cluster. Although in vitro and in vivo efficacy and toxicity studies indicate that NPP B1 is a promising lead antifungal compound, further improvement is required to increase the extremely low production yield in the pathway-engineered strain.

Corynebacterium Cell Factory Design and Culture Process Optimization for Muconic Acid Biosynthesis.

Muconic acid (MA) is a valuable compound for adipic acid production, which is a precursor for the synthesis of various polymers such as plastics, coatings, and nylons. Although MA biosynthesis has been previously reported in several bacteria, the engineered strains were not satisfactory owing to low MA titers. Here, we generated an engineered Corynebacterium cell factory to produce a high titer of MA through 3-dehydroshikimate (DHS) conversion to MA, with heterologous expression of foreign protocatechuate (PCA) decarboxylase genes.