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A pair of new quinolone alkaloid enantiomers, (Ra)-(-)-viridicatol (1) and (Sa)-(+)-viridicatol (4), and seven known compounds, namely, 2, 3 and 5–9, were isolated from Penicillium christenseniae SD.84. The structures of 1 and 4 were determined using NMR and HRESIMS data. Theoretical calculations through CD and ECD confirmed 1 and 4 as a pair of enantiomers. The MIC values of 4 against Staphylococcus aureus and methicillin-resistant S. aureus were 12.4 and 24.7 μM, respectively, compound 1 had no inhibitory activity. Antimicrobial assays of 2, 3, and 5–7 showed a moderate activity against S. aureus and methicillin-resistant S. aureus. This study demonstrated the remarkable potential of Penicillium sp. to produce new drug-resistant leading compounds, thereby advancing the mining for new sources of antimicrobial agents.

Obesity, dyslipidemia and gut dysbiosis are all linked to cardiovascular diseases. A Ganoderma meroterpene derivative (GMD) has been shown to alleviate obesity and hyperlipidemia through modulating the gut microbiota in obese mice. Here we show that GMD protects against obesity-associated atherosclerosis by increasing the abundance of Parabacteroides merdae in the gut and enhancing branched-chain amino acid (BCAA) catabolism. Administration of live P. merdae to high-fat-diet-fed ApoE-null male mice reduces atherosclerotic lesions and enhances intestinal BCAA degradation. The degradation of BCAAs is mediated by the porA gene expressed in P. merdae. Deletion of porA from P. merdae blunts its capacity to degrade BCAAs and leads to inefficacy in fighting against atherosclerosis. We further show that P. merdae inhibits the mTORC1 pathway in atherosclerotic plaques. In support of our preclinical findings, an in silico analysis of human gut metagenomic studies indicates that P. merdae and porA genes are depleted in the gut microbiomes of individuals with atherosclerosis. Our results provide mechanistic insights into the therapeutic potential of GMD through P. merdae in treating obesity-associated cardiovascular diseases.

Interactions between gut microbiome and host immune system are fundamental to maintaining the intestinal mucosal barrier and homeostasis. At the host-gut microbiome interface, cell wall-derived molecules from gut commensal bacteria have been reported to play a pivotal role in training and remodeling host immune responses. In this article, we review gut bacterial cell wall-derived molecules with characterized chemical structures, including peptidoglycan and lipid-related molecules that impact host health and disease processes via regulating innate and adaptive immunity. Also, we aim to discuss the structures, immune responses, and underlying mechanisms of these immunogenic molecules. Based on current advances, we propose cell wall-derived components as important sources of medicinal agents for the treatment of infection and immune diseases.

Ophiocordyceps sinensis is a well-known entomogenous fungus with its fruiting bodies or cultural mycelium as food and herbal medicines in Asia. While metabolites which could responsible for its potent pharmaceutical effects has long remained to be elucidated. In this work, chemical investigation on the solid culture of O. sinensis strain LY34 led to the discovery of six digalactosyldiacylglycerols (DGDGS, 1–6) including one new. The structure of compound 1 was determined based on the comprehensive spectra analysis, including NMR, MSn, IR, and chemical derivatisation. Bioactivity studies showed a weak cytotoxicity of compounds 1–6 against 293 T cell and medium anti-inflammatory activity of compounds 1 and 2 on Raw 264.7 cell. The discovery of DGDGs in O. sinensis provides new insight into the pharmacologically active substances.

Natural products modulate interactions between gut microbiota and host.

Phytopathogenic fungi have attracted great attention as a promising source for new drug discovery. In the progress of our ongoing study for bioactive natural products from an in-house phytopathogenic fungi library, a pathogenic fungus, Fusarium proliferatum strain 13294 (FP13294), was selected for chemical investigation. Two novel aliphatic unsaturated alcohols named fusariumnols A and B (1 and 2), together with one previously characterized sesquiterpenoid lignoren (3) were identified. Structures of 1–3 were assigned by mass spectrometry and NMR spectroscopy. Their bioactivities were assessed against Staphylococcus epidermidis, S. aureus, and Methicillin-resistant S. aureus (MRSA). Compounds 1 and 2 exhibited weak antibacterial activity against S. epidermidis (MIC = 100 μM).

Gut fungi is known to play many important roles in human health regulations. Herein, we investigate the anti-obesity efficacy of the antifungal antibiotics (amphotericin B, fluconazole and 5-fluorocytosine) in the high fat diet-fed (HFD) mice. Supplementation of amphotericin B or fluconazole in water can effectively inhibit obesity and its related disorders, whereas 5-fluorocytosine exhibit little effects. The gut fungus Candida parapsilosis is identified as a key commensal fungus related to the diet-induced obesity by the culture-dependent method and the inoculation assay with C. parapsilosis in the fungi-free mice. In addition, the increase of free fatty acids in the gut due to the production of fungal lipases from C. parapsilosis is confirmed as one mechanism by which C. parapsilosis promotes obesity. The current study demonstrates the gut C. parapsilosis as a causal fungus for the development of diet-induced obesity in mice and highlights the therapeutic strategy targeting the gut fungi., Shanshan Sun, Li Sun, Kai Wang, et al. report that the gut commensal Candida parapsilosis is a causative fungus for the development of high fat-diet induced obesity in mice. Their results suggest that fungi could represent possible targets for combating obesity.

A pair of new quinolone alkaloid enantiomers, (

Candida albicans is a life-threatening, opportunistic fungal pathogen with a high mortality rate, especially within the immunocompromised populations. Multidrug resistance combined with limited antifungal drugs even worsens the situation. Given the facts that the current drug discovery strategies fail to deliver sufficient antifungals for the emerging multidrug resistance, we urgently need to develop novel approaches. By systematically investigating what caused the different antifungal activity of rapamycin in RPMI 1640 and YPD, we discovered that peptide-like compounds can generate a hyper-synergistic antifungal effect with rapamycin on both azole-resistant and sensitive clinical C. albicans isolates. The minimum inhibitory concentration (MIC) of rapamycin reaches as low as 2.14 nM (2-9 μg/mL), distinguishing this drug combination as a hyper-synergism by having a fractional inhibitory concentration (FIC) index ≤ 0.05 from the traditional defined synergism with an FIC index < 0.5. Further studies reveal that this hyper-synergism orthogonally targets the protein Tor1 and affects the TOR signaling pathway in C. albicans, very likely without crosstalk to the stress response, Ras/cAMP/PKA, or calcineurin signaling pathways. These results lead to a novel strategy of controlling drug resistant C. albicans infection in the immunocompromised populations. Instead of prophylactically administering other antifungals with undesirable side-effects for extended durations, we now only need to coadminister some nontoxic peptide additives. The novel antifungal strategy approached in this study not only provides a new therapeutic method to control fungal infections in rapamycin-taking immunocompromised patients but also mitigates the immunosuppressive side-effects of rapamycin, repurposing rapamycin as an antifungal agent with wide applications.

Fungal terpenoids catalyzed by bifunctional terpene synthases (BFTSs) possess interesting bioactive and chemical properties. In this study, an integrated approach of genome mining, heterologous expression, and in vitro enzymatic activity assay was used, and these identified a unique BFTS sub-clade critical to the formation of a 5-15 trans-fused bicyclic sesterterpene preterpestacin I (1). The 5-15 bicyclic BFTS gene clusters were highly conserved but showed relatively wide phylogenetic distribution across several species of the diverged fungal classes Dothideomycetes and Sordariomycetes. Further genomic organization analysis of these homologous biosynthetic gene clusters from this clade revealed a glycosyltransferase from the graminaceous pathogen Bipolaris sorokiniana isolate BS11134, which was absent in other 5-15 bicyclic BFTS gene clusters. Targeted isolation guided by BFTS gene deletion led to the identification of two new sesterterpenoids (4, and 6) from BS11134. Compounds 2 and 4 showed moderate effects on LPS-induced nitrous oxide production in the murine macrophage-like cell line RAW264.7 with in vitro inhibition rates of 36.6 ± 2.4% and 24.9 ± 2.1% at 10 μM, respectively. The plausible biosynthetic pathway of these identified compounds was proposed as well. This work revealed that phytopathogenic fungi can serve as important sources of active terpenoids via systematic analysis of the genomic organization of BFTS biosynthetic gene clusters, their phylogenetic distribution in fungi, and cyclization properties of their metabolic products. KEY POINTS: • Genome mining of the first BFTS BGC harboring a glycosyltransferase. • Gene-deletion guided isolation revealed three novel 5-15 bicyclic sesterterpenoids. • Biosynthetic pathway of isolated sesterterpenoids was proposed.

Marine microbes provide an important resource to discover new chemical compounds with biological activities beneficial to drug discovery. In our study, two new polyene macrolides, pyranpolyenolides A (1) and B (2), and one new natural cyclic peptide (9), together with two known polyenes (7 and 8) and three known cyclic peptides (10-12), were isolated from a culture of the marine Streptomyces sp. MS110128. In addition, four new polyene macrolides, pyranpolyenolides C-F (3-6), were identified as olefin geometric isomers that were most likely produced by photochemical conversion during the cultivation or isolation procedures. The pyranpolyenolides are 32-membered macrolides endowed with a conjugated tetraene and several pairs of 1,3-dihydroxyl groups. Pyranpolyenolides that contain a hydropyran group have not been previously reported. Four cyclic peptides (9-12) showed significant activities against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant S. aureus with supporting MIC values ranging from 0.025 to 1.25 μg/mL. These cyclic peptides containing piperazic moieties showed moderate activities with MIC values of 12.5 μg/mL against Bacille Calmette Guerin (BCG), an attenuated form of the bovine. Additionally, cyclic peptide 12 showed moderate antifungal activity against Candida albicans with an MIC value of 12.5 μg/mL. KEY POINTS: • Discovery of new polyenes and cyclic peptides from a marine-derived Actinomycete. • Cyclic peptides containing piperazic moieties exhibited good antibacterial activity.

Two new cyclohexadepsipeptides japonamides A (1) and B (2) were isolated from the ethyl acetate extract of a marine-sponge-derived fungus

The current global demand for novel anti-TB drugs has drawn urgent attention on the discovery of natural product compounds with anti-TB activity. Lots of efforts have emphasized on environmental samples from unexplored or underexplored natural habits and identified numerous rare actinomycete taxa producing structurally diverse bioactive natural products. Herein, we report a survey of the rare actinobacteria diversity in Xinjiang region together with the discovery of anti-TB active natural products from these strains. We have collected 17 soil samples at different sites with different environmental conditions, from which 39 rare actinobacteria were identified by using a selective isolation strategy with 5 media variations. Among those isolated strains, XJ31 was identified as a new Nocardia sp. based on 16S rRNA gene analysis. Through one strain-many compounds (OSMAC) strategy combined with anti-Bacillus Calmette-Guérin bioassay-guided isolation, two groups of compounds were identified. They were twelve siderophores (nocardimicins, 1-12) and two anthraquinones (brasiliquinones, 13 and 14) and ten of them were identified as new compounds. The structures of the purified compounds were elucidated using HR-ESI-MS, 1D NMR, and 2D NMR techniques. The anti-TB bioassays revealed that the two benz[α]anthraquinones have potent activity against BCG (MICs = 25 μM), which can be used as a promising start point for further anti-TB drug development. Key points • Ten new natural products were identified from Nocardia sp. XJ31. • Brasiliquinones 13 and 14 showed moderate anti-BCG activity. Electronic supplementary material The online version of this article (10.1007/s00253-020-10842-2) contains supplementary material, which is available to authorized users.

Tuberculosis (TB) is a life-threatening disease resulting in an estimated 10 million new infections and 1.8 million deaths annually, primarily in underdeveloped countries. The economic burden of TB has been estimated as approximately 12 billion USD annually in direct and indirect costs. Additionally, multi-drug-resistant (MDR) and extreme-drug-resistant (XTR) TB strains resulting in about 250 000 deaths annually are now widespread, increasing pressure on the identification of new anti-TB agents that operate by a novel mechanism of action. Chrysomycin A is a rare C-aryl glycoside first discovered over 60 years ago. In a recent high-throughput screen, we found that chrysomycin A has potent anti-TB activity, with minimum inhibitory concentration (MIC) = 0.4 μg/mL against MDR-TB strains. However, chrysomycin A is obtained in low yields from fermentation of Streptomyces, and the mechanism of action of this compound is unknown. To facilitate the mechanism of action and preclinical studies of chrysomycin A, we developed a 10-step, scalable synthesis of the isolate and its two natural congeners polycarcin V and gilvocarcin V. The synthetic sequence was enabled by the implementation of two sequential C–H functionalization steps as well as a late-stage C-glycosylation. In addition, >10 g of the advanced synthetic intermediate has been prepared, which greatly facilitated the synthesis of 33 new analogues to date. The structure–activity relationship was subsequently delineated, leading to the identification of derivatives with superior potency against MDR-TB (MIC = 0.08 μg/mL). The more potent derivatives contained a modified carbohydrate residue which suggests that further optimization is additionally possible. The chemistry we report here establishes a platform for the development of a novel class of anti-TB agents active against drug-resistant pathogens., We report a 10-step and scalable synthesis of chrysomycin A, a potent anti-TB C-aryl glycoside. The synthesis highlights sequential C-H functionalizations and the late-stage diversification.

Methicillin-resistant Staphylococcus aureus (MRSA), a WHO high-priority pathogen that can cause great harm to living beings, is a primary cause of death from antibiotic-resistant infections. In the present study, six new compounds, including fumindoline A–C (1–3), 12β, 13β-hydroxy-asperfumigatin (4), 2-epi-tryptoquivaline F (17) and penibenzophenone E (37), and thirty-nine known ones were isolated from the marine-derived fungus Aspergillus fumigatus H22. The structures and the absolute configurations of the new compounds were unambiguously assigned by spectroscopic data, mass spectrometry (MS), electronic circular dichroism (ECD) spectroscopic analyses, quantum NMR and ECD calculations, and chemical derivatizations. Bioactivity screening indicated that nearly half of the compounds exhibit antibacterial activity, especially compounds 8 and 11, and 33–38 showed excellent antimicrobial activities against MRSA, with minimum inhibitory concentration (MIC) values ranging from 1.25 to 2.5 μM. In addition, compound 8 showed moderate inhibitory activity against Mycobacterium bovis (MIC: 25 μM), compound 10 showed moderate inhibitory activity against Candida albicans (MIC: 50 μM), and compound 13 showed strong inhibitory activity against the hatching of a Caenorhabditis elegans egg (IC50: 2.5 μM).

Methicillin-resistant

Under the guidance of LC-MS/MS-based molecular networking, seven new verrucosidin derivatives, penicicellarusins A-G (3–9), were isolated together with three known analogues from the fungus Penicillium cellarum. The structures of the new compounds were determined by a combination of NMR, mass and electronic circular dichroism spectral data analysis. The absolute configuration of penicyrone A (10) was corrected based on X-ray diffraction analyses. Bioactivity screening indicated that compounds 1, 2, and 4 showed much stronger promising hypoglycemic activity than the positive drug (rosiglitazone) in the range of 25–100 μM, which represents a potential new class of hypoglycemic agents. Preliminary structure-activity relationship analysis indicates that the formation of epoxy ring on C6-C7 in the structures is important for the glucose uptake-stimulating activity. The gene cluster for the biosynthesis of 1–12 is identified by sequencing the genome of P. cellarum and similarity analysis with the gene cluster of verrucosidins in P. polonicum.

Fungal natural products play a prominent role in the development of pharmaceuticalagents. Two new cyclic tetrapeptides (CTPs), westertide A (1) and B (2), with eight known compounds (3–10) were isolated from the fungus Aspergillus westerdijkiae guided by OSMAC (one strain-many compounds) and molecular networking strategies. The structures of new compounds were unambiguously determined by a combination of NMR and mass data analysis, and chemical methods. All of the isolates were evaluated for antimicrobial effects, synergistic antifungal activity, cytotoxic activity, and HDAC inhibitory activity. Compounds 1–2 showed synergistic antifungal activity against Candida albicans SC5314 with the presence of rapamycin and weak HDAC (histone deacetylase) inhibitory activity. These results indicate that molecular networking is an efficient approach for dereplication and identification of new CTPs. CTPs might be a good starting point for the development of synergistic antifungal agents.

Under the guidance of LC-MS/MS-based molecular networking, seven new verrucosidin derivatives, penicicellarusins A-G (

Pleuromutilins, the unique fungal metabolites possessing 5/6/8 tricyclic skeleton, are potent antibacterial leading compounds for the development of new antibiotics. We applied the MS/MS molecular networking technique and the combinatorial biosynthesis approach to discover new pleuromutilin analogues. Ten pleuromutilin derivatives including seven new compounds (1-7) were obtained from the solid culture of Omphalina mutila. The gene cluster for the biosynthesis of pleuromutilins in the mushroom of O. mutila was identified and further expressed in yeast. Nine pleuromutilin-type diterpenes including three new "unnatural" pleuromutilins (16-18) were generated in a GGPP-engineered Saccharomyces cerevisiae. The antimicrobial bioassays indicated that compounds 3, 9, 10, 15, and 17 exhibited potent inhibition against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). Several pleuromutilins were found to show immunomodulatory activities by promoting the cell viability, enhancing the ROS and NO production, or increasing the levels of proinflammatory cytokines IL-6 and TNF-α in the macrophage RAW 264.7. The structure-activity relationship for pleuromutilins was analyzed.

Fungal natural products play a prominent role in the development of pharmaceuticalagents. Two new cyclic tetrapeptides (CTPs), westertide A (

Atherosclerosis is a chronic inflammatory disease of arteries featured with accumulated lipids, becoming the primary cause of cardiovascular diseases and death. Branched-chain amino acids (BCAAs) accumulation is defined as biomarkers of cardiometabolic diseases. Here, we revealed metabolic benefits of a previously reported gut microbiota-modulator (GMD) on atherosclerosis in ApoE−/− mice, and identify a gut symbiont Parabacteroides merdae-driven BCAA catabolism beneficial for the alleviation of atherosclerosis lesions. We also show that the porA gene responsible for the conversion of BCAAs into branched short-chain fatty acids is required for the in vivo efficacy of P. merdae. Furthermore, the down-regulation of BCAA-activated plaque mammalian target of rapamycin complex 1 (mTORC1) pathway is suggested as the mechanism underlying the benefits of P. merdae. Our results demonstrate the critical role of the commensal bacteria-driven BCAA catabolism in maintaining the host cardiovascular health and supporting the gut microbiota-targeted therapeutic strategy for cardiometabolic diseases.

Polyketide–terpenoid hybrid compounds are one of the largest families of meroterpenoids, with great potential for drug development for resistant pathogens. Genome sequence analysis of secondary metabolite gene clusters of a phytopathogenic fungus, Bipolaris sorokiniana 11134, revealed a type I polyketide gene cluster, consisting of highly reducing polyketide synthase, non-reducing polyketide synthase, and adjacent prenyltransferase. MS- and UV-guided isolations led to the isolation of ten meroterpenoids, including two new compounds: 19-dehydroxyl-3-epi-arthripenoid A (1) and 12-keto-cochlioquinone A (2). The structures of 1–10 were elucidated by the analysis of NMR and high-resolution electrospray ionization mass spectroscopy data. Compounds 5–8 and 10 showed moderate activity against common Staphylococcus aureus and methicillin-resistant S. aureus, with minimum inhibitory concentration (MIC) values of 12.5–100 μg/mL. Compound 5 also exhibited activity against four clinical resistant S. aureus strains and synergistic antifungal activity against Candida albicans with MIC values of 12.5–25 μg/mL. The biosynthetic gene cluster of the isolated compounds and their putative biosynthetic pathway are also proposed. • Ten meroterpenoids were identified from B. sorokiniana, including two new compounds. • Cochlioquinone B (5) showed activity against MRSA and synergistic activity against C. albicans. • The biosynthetic gene cluster and biosynthetic pathway of meroterpenoids are proposed. • Genome mining provided a new direction to uncover the diversity of meroterpenoids.

Increasing attention has recently been focused on complex symbiotic associations, for instance coral and its symbionts. Sea cucumber, harboring diverse fungi, has also attracted more and more attention for their functional diversity. Here, secondary metabolites produced by Chaetomium globosum associated with sea cucumber, Apostichopus japonicus, were investigated using gene mining with third-generation sequencing technology (PacBio SMRT). Nine compounds, including one new compound cytoglobosin X (1), were isolated from cultures of Chaetomium globosum. Compound 1 was identified based on NMR data, HRESIMS, and ECD, and the absolute configurations were identified as 3S, 4R, 7S, 8R, 9R, 16S, 19S, 20S, and 23S. In an antimicrobial assay, compound 4 showed moderate activity against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus with MICs of 47.3 and 94.6 μM, respectively. Our results suggest that the microbiomes associated with sea cucumber could be an important resource for biodiversity and structural novelty, and the bioactive compounds may protect the host from pathogen microbial.

Two pairs of dibenzospiroketal racemates, (±)-epicospirocin A (1a/1b) and (±)-1-epi-epicospirocin A (2a/2b), and two (+)-enantiomers of aspermicrones, ent-aspermicrone B (3b) and ent-aspermicrone C (4b), together with two hemiacetal epimeric mixtures, epicospirocin B/1-epi-epicospirocin B (5/6) and epicospirocin C/1-epi-epicospirocin C (7/8), were investigated from the phytopathogenic fungus Epicoccum nigrum 09116 via MS/MS molecular networking guided isolation and chiral separation for the first time. A plausible epicospirocin biosynthetic pathway was elucidated through in silico gene function annotation together with knock-out experiments. This is the first report that has applied MS/MS molecular networking to identify intermediates correlated with a biosynthetic pathway.

Five new chromone methide polymers, (±)-amplisins A–D (1–4) and amplisin E (5), were isolated from a new fungicolous fungus Amplistroma fungicola. Compounds 1–5 were determined to have unusual chemical skeletons with two or three chromone methide groups linked with different polyketides. A non-enzymatic 1,4-Michael addition of chromone methide was verified in the biosynthesis of 1–5. Compounds 1 and 2 showed inhibition of PTP1B and stimulation of glucose uptake in insulin-resistant HepG2 cells. Compounds 3–5 exhibited strong NO inhibition of LPS-activated macrophages.

During the systematic screening of bioactive compounds from our marine natural product library, crude extract of the marine-derived fungus strain Aspergillus fumigatus MF029 exhibited moderate bioactivities against Bacillus subtilis, Staphylococcus aureus, methicillin-resistant S. aureus, and Mycobacterium bovis bacillus Calmette-Guerin (BCG). Further chemical investigation resulted in the identification of two new compounds, chaetominine A (1) and sphingofungin I (2), together with four known compounds, emodin (3), chaetominine (4), sphingofungin D (5) and trypacidin (6). Trypacidin displayed potential antitubercular activity with MIC value of 1.25 μg/mL.

Besides genome editing, CRISPR-Cas12a has recently been used for DNA detection applications with attomolar sensitivity but, to our knowledge, it has not been used for the detection of small molecules. Bacterial allosteric transcription factors (aTFs) have evolved to sense and respond sensitively to a variety of small molecules to benefit bacterial survival. By combining the single-stranded DNA cleavage ability of CRISPR-Cas12a and the competitive binding activities of aTFs for small molecules and double-stranded DNA, here we develop a simple, supersensitive, fast and high-throughput platform for the detection of small molecules, designated CaT-SMelor (CRISPR-Cas12a- and aTF-mediated small molecule detector). CaT-SMelor is successfully evaluated by detecting nanomolar levels of various small molecules, including uric acid and p-hydroxybenzoic acid among their structurally similar analogues. We also demonstrate that our CaT-SMelor directly measured the uric acid concentration in clinical human blood samples, indicating a great potential of CaT-SMelor in the detection of small molecules., Bacterial allosteric transcription factors can sense and respond to a variety of small molecules. Here the authors present CaT-SMelor which uses Cas12a and allosteric transcription factors to detect small molecules in the nanomolar range.

Polysaccharides are known to confer protection against obesity via modulation of gut microbiota. To expand our knowledge of mushroom-derived prebiotics, we investigated the structural characteristics and anti-obesity effects of Lyophyllum decastes polysaccharides. Two heteroglycans were purified and characterized. The isolated polysaccharides effectively reduced obesity and the related disorders in the diet-induced obese (DIO) mice. An altered gut microbiota with enrichments of Bacteroides intestinalis and Lactobacillus johnsonii and an increase of secondary bile acids were detected in the polysaccharide-treated mice. Supplementation of B. intestinalis and L. johnsonii prevented the obesity and hyperlipidemia in DIO mice, demonstrating their causal linkage to the efficacy of polysaccharides. An enhancement of energy expenditure in the brown adipose tissues due to up-regulation of the secondary bile acids-activated TGR5 pathway was deduced to be one of the mechanisms underlying the effect of polysaccharides. These results confirmed Lyophyllum decastes-derived polysaccharides as new prebiotics for preventing and treating obesity.

Two new cyclohexadepsipeptides japonamides A (1) and B (2) were isolated from the ethyl acetate extract of a marine-sponge-derived fungus Aspergillus japonicus based on molecular networking. Their structures were elucidated by comprehensive spectral analysis and their absolute configurations were confirmed by Marfey’s method. Compounds 1 and 2 showed no antifungal activities against Candida albicans SC5314 measured by the broth microdilution method but exhibited prominent synergistic antifungal activities in combination with fluconazole, ketoconazole, or rapamycin. The Minimum inhibitory concentrations (MICs) of rapamycin, fluconazole, and ketoconazole were significantly decreased from 0.5 to 0.002 μM, from 0.25 to 0.063 μM, and from 0.016 to 0.002 μM, in the presence of compounds 1 or 2 at 3.125 μM, 12.5 μM, and 6.25 μM, respectively. Surprisingly, the combination of compounds 1 or 2 with rapamycin showed a strong synergistic effect, with fractional inhibitory concentration index (FICI) values of 0.03.

During the systematic screening of bioactive compounds from our marine natural product library, crude extract of the marine-derived fungus strain

Bacterial drug resistance has become a growing problem worldwide due to the excessive use of antibiotics in recent decades. Two small focused libraries of 5H-pyrimido[5,4-b]indole-4-carboxamides and 5H-pyrimido-[5,4-b]indole-4-ketones were designed as eudistomin Y3 and 1-acetyl-β-carboline (1-ABC) analogs and prepared via application of Inverse Electron-Demand Diels-Alder (IEDDA) reaction of 1,3,5-triazines and 3-aminoindoles. Compounds 2a and 2b were discovered to have activity against Mycobacterium bovis BCG with Minimum Inhibitory Concentration (MICs) values of 25 and 50 μg/mL respectively while compound 2e was against all three strains of Candida albicans tested with MIC values of 50 μg/mL. Moreover, compound 2e demonstrated synergistic antibacterial activity with fluconazol, which suggested that future drug candidates from this class of compounds could be used in combination with existing drugs to treat C. albicans infections.

Gut fungi is known to play many important roles in human health regulations. Herein, we investigated the anti-obesity efficacy of the antifungal antibiotics (amphotericin B, fluconazole and 5-fluorocytosine) in the high fat diet-fed (HFD) mice. Supplementation of amphotericin B or fluconazole in water effectively inhibited obesity and its related disorders, whereas 5-fluorocytosine exhibited little effects. The gut fungus Candida parapsilosis was identified as a key commensal fungus related to the diet-induced obesity by the culture-dependent method and the inoculation assay with C. parapsilosis in the fungi-free mice. In addition, the increase of free fatty acids in the gut due to the production of fungal lipases from C. parapsilosis was confirmed as one mechanism by which C. parapsilosis promotes obesity. The current study demonstrates the gut C. parapsilosis as a causal fungus for the development of diet-induced obesity in mice and highlights the therapeutic strategy targeting the gut fungi.

A chemical investigation on the fermentation products of Sanghuangporus sanghuang led to the isolation and identification of fourteen secondary metabolites ( 1 − 14 ) including eight sesquiterpenoids ( 1 − 8 ) and six polyphenols ( 9 − 14 ). Compounds 1 − 3 were sesquiterpenes with new structures which were elucidated based on NMR spectroscopy, high resolution mass spectrometry (HRMS) and electronic circular dichroism (ECD) data. All the isolates were tested for their stimulation effects on glucose uptake in insulin-resistant HepG2 cells, and cellular antioxidant activity. Compounds 9 − 12 were subjected to molecular docking experiment to primarily evaluate their anti-coronavirus (SARS-CoV-2) activity. As a result, compounds 9 − 12 were found to increase the glucose uptake of insulin-resistant HepG2 cells by 18.1%, 62.7%, 33.7% and 21.4% at the dose of 50 μmol·L−1, respectively. Compounds 9 − 12 also showed good cellular antioxidant activities with CAA50 values of 12.23, 23.11, 5.31 and 16.04 μmol·L−1, respectively. Molecular docking between COVID-19 Mpro and compounds 9 − 12 indicated potential SARS-CoV-2 inhibitory activity of these four compounds. This work provides new insights for the potential role of the medicinal mushroom S. sanghuang as drugs and functional foods.

Tuberculosis drug resistance continues to threaten global health but the underline molecular mechanisms are not clear. Ethambutol (EMB), one of the well-known first - line drugs in tuberculosis treatment is, unfortunately, not free from drug resistance problems. Genomic studies have shown that some genetic mutations in Mycobacterium tuberculosis (Mtb) EmbR, and EmbC/A/B genes cause EMB resistance. EmbR-PknH pair controls embC/A/B operon, which encodes EmbC/A/B genes, and EMB interacts with EmbA/B proteins. However, the EmbR binding site on PknH was unknown. We conducted molecular simulation on the EmbR– peptides binding structures and discovered phosphorylated PknH 273–280 (N′-HEALSPDPD-C′) makes β strand with the EmbR FHA domain, as β-MoRF (MoRF; molecular recognition feature) does at its binding site. Hydrogen bond number analysis also supported the peptides' β-MoRF forming activity at the EmbR FHA domain. Also, we discovered that previously known phosphorylation residues might have their chronological order according to the phosphorylation status. The discovery validated that Mtb PknH 273–280 (N′-HEALSDPD-C′) has reliable EmbR binding affinity. This approach is revolutionary in the computer-aided drug discovery field, because it is the first trial to discover the protein-protein interaction site, and find binding partner in nature from this site.

Marine microbes provide an important resource to discover new chemical compounds with biological activities beneficial to drug discovery. In our study, two new polyene macrolides, pyranpolyenolides A (1) and B (2), and one new natural cyclic peptide (9), together with two known polyenes (7 and 8) and three known cyclic peptides (10-12), were isolated from a culture of the marine Streptomyces sp. MS110128. In addition, four new polyene macrolides, pyranpolyenolides C-F (3-6), were identified as olefin geometric isomers that were most likely produced by photochemical conversion during the cultivation or isolation procedures. The pyranpolyenolides are 32-membered macrolides endowed with a conjugated tetraene and several pairs of 1,3-dihydroxyl groups. Pyranpolyenolides that contain a hydropyran group have not been previously reported. Four cyclic peptides (9-12) showed significant activities against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant S. aureus with supporting MIC values ranging from 0.025 to 1.25 μg/mL. These cyclic peptides containing piperazic moieties showed moderate activities with MIC values of 12.5 μg/mL against Bacille Calmette Guerin (BCG), an attenuated form of the bovine. Additionally, cyclic peptide 12 showed moderate antifungal activity against Candida albicans with an MIC value of 12.5 μg/mL. KEY POINTS: • Discovery of new polyenes and cyclic peptides from a marine-derived Actinomycete. • Cyclic peptides containing piperazic moieties exhibited good antibacterial activity.

Fungal terpenoids catalyzed by bifunctional terpene synthases (BFTSs) possess interesting bioactive and chemical properties. In this study, an integrated approach of genome mining, heterologous expression, and in vitro enzymatic activity assay was used, and these identified a unique BFTS sub-clade critical to the formation of a 5-15 trans-fused bicyclic sesterterpene preterpestacin I (1). The 5-15 bicyclic BFTS gene clusters were highly conserved but showed relatively wide phylogenetic distribution across several species of the diverged fungal classes Dothideomycetes and Sordariomycetes. Further genomic organization analysis of these homologous biosynthetic gene clusters from this clade revealed a glycosyltransferase from the graminaceous pathogen Bipolaris sorokiniana isolate BS11134, which was absent in other 5-15 bicyclic BFTS gene clusters. Targeted isolation guided by BFTS gene deletion led to the identification of two new sesterterpenoids (4, and 6) from BS11134. Compounds 2 and 4 showed moderate effects on LPS-induced nitrous oxide production in the murine macrophage-like cell line RAW264.7 with in vitro inhibition rates of 36.6 ± 2.4% and 24.9 ± 2.1% at 10 μM, respectively. The plausible biosynthetic pathway of these identified compounds was proposed as well. This work revealed that phytopathogenic fungi can serve as important sources of active terpenoids via systematic analysis of the genomic organization of BFTS biosynthetic gene clusters, their phylogenetic distribution in fungi, and cyclization properties of their metabolic products. KEY POINTS: • Genome mining of the first BFTS BGC harboring a glycosyltransferase. • Gene-deletion guided isolation revealed three novel 5-15 bicyclic sesterterpenoids. • Biosynthetic pathway of isolated sesterterpenoids was proposed.

A chemical investigation on the fruiting bodies of

Due to the increasing prevalence of pathogenic fungal infections, the emergence of antifungal resistant clinical isolates worldwide, and the limited arsenal of available antifungals, developing new antifungal strategies is imperative. In this study, we screened a library of 1068 FDA-approved drugs to identify hits that exhibit broad-spectrum antifungal activity. Robenidine, an anticoccidial agent which has been widely used to treat coccidian infections of poultry and rabbits, was identified in this screen. Physiological concentration of robenidine (8 μM) was able to significantly inhibit yeast cell growth, filamentation and biofilm formation of Candida albicans – the most extensively studied human fungal pathogen. Moreover, we observed a broad-spectrum antifungal activity of this compound against fluconazole resistant clinical isolates of C. albicans, as well as a wide range of other clinically relevant fungal pathogens. Intriguingly, robenidine-treated C. albicans cells were hypersensitive to diverse cell wall stressors, and analysis of the cell wall structure by transmission electron microscopy (TEM) showed that the cell wall was severely damaged by robenidine, implying that this compound may target the cell wall integrity signaling pathway. Indeed, upon robenidine treatment, we found a dose dependent increase in the phosphorylation of the cell wall integrity marker Mkc1, which was decreased after prolonged exposure. Finally, we provide evidence by RNA-seq and qPCR that Rlm1, the downstream transcription factor of Mkc1, may represent a potential target of robenidine. Therefore, our data suggest that robenidine, a FDA approved anti-coccidiosis drug, displays a promising and broadly effective antifungal strategy, and represents a potentially repositionable candidate for the treatment of fungal infections.

Background The aim was to determine the potential association of the gut microbiota composition, especially the abundance of Actinobacteria, as well as the differentiation of functional and resistance genes with age (young adults vs elderly subjects) in China. Results The patterns of relative abundance of all bacteria isolated from fecal samples differed between young adults and elderly subjects, but the alpha diversity (Chao1 P = 0.370, Shannon P = 0.560 and Simpson P = 0.270) and beta diversity (ANOSIM R = 0.031, P = 0.226) were not significantly different. There were 3 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways (carbon metabolism, inositol phosphate metabolism, and sesquiterpenoid and triterpenoid biosynthesis) and 7 antibiotic resistant genes (ARGs) (macrolide lincosamide-streptogramin B (MLSB), tetracycline, aminoglycoside, sulfonamide, fosmidomycin, lincomycin, and vancomycin) that showed significant differences between the 2 groups (all P Actinomycetes was enriched (about 2.4-fold) in young adults. Bifidobacteria dominated in both young adults and elderly subjects, with overall higher abundances in young adults (P > 0.05). Only the Bifidobacterium_dentium species showed significant differences between the 2 groups (P = 0.013), with a higher abundance in elderly subjects but absent in young adults. Conclusions The present study revealed that there were 3 KEGG metabolic pathways and 7 ARGs as well as enhanced Bifidobacterium_dentium species abundance in elderly compared to young subjects.

Candida albicans has been detected in root carious lesions. The current study aimed to explore the action of this fungal species on the microbial ecology and the pathogenesis of root caries. Here, by analyzing C. albicans in supragingival dental plaque collected from root carious lesions and sound root surfaces of root-caries subjects as well as caries-free individuals, we observed significantly increased colonization of C. albicans in root carious lesions. Further in vitro and animal studies showed that C. albicans colonization increased the cariogenicity of oral biofilm by altering its microbial ecology, leading to a polymicrobial biofilm with enhanced acidogenicity, and consequently exacerbated tooth demineralization and carious lesion severity. More importantly, we demonstrated that the cariogenicity-promoting activity of C. albicans was dependent on PHR2. Deletion of PHR2 restored microbial equilibrium and led to a less cariogenic biofilm as demonstrated by in vitro artificial caries model or in vivo root-caries rat model. Our data indicate the critical role of C. albicans infection in the occurrence of root caries. PHR2 is the major factor that determines the ecological impact and caries-promoting activity of C. albicans in a mixed microbial consortium.

Summary Pioneering microbial genomic surveys have revealed numerous untapped biosynthetic gene clusters, unveiling the great potential of new natural products. Here, using a combination of genome mining, mutasynthesis, and activity screening in an infection model comprising Caenorhabditis elegans and Pseudomonas aeruginosa, we identified candidate virulence-blocking amychelin siderophore compounds from actinomycetes. Subsequently, we developed unreported analogs of these virulence-blocking siderophores with improved potency by exploiting an Amycolatopsis methanolica strain 239T chorismate to salicylate a biosynthetic subpathway for mutasynthesis. This allowed us to generate the fluorinated amychelin, fluoroamychelin I, which rescued C. elegans from P. aeruginosa-mediated killing with an EC50 value of 1.4 μM, outperforming traditional antibiotics including ceftazidime and meropenem. In general, this paper describes an efficient platform for the identification and production of classes of anti-microbial compounds with potential unique modes of action.

As an anti-tuberculosis target, DprE1 contains two flexible loops (Loop I and Loop II) which have never been exploited for developing DprE1 inhibitors. Here Leu317 in Loop II was discovered as a new functional site to combat drug-resistance in Mycobacterium strains. Based on TCA1, LZDT1 was designed to optimize the hydrophobic interaction with Leu317. A subsequent biochemical and cellular assay displayed increased potency of LZDT1 in inhibiting DprE1 and killing drug-sensitive/-resistant Mycobacterium strains. The improved activity of LZDT1 and its analogue LZDT2 against multidrug resistant tuberculosis was particularly highlighted. For LZDT1, its enhanced interaction with Leu317 also impaired the drug-insensitivity of DprE1 caused by Cys387 mutation. A new nonbenzothiazole lead (LZDT10) with reduced Cys387-dependence was further produced by optimizing interactions with Leu317, improvement directions for LZDT10 were discussed as well. Our research underscores the value of potential functional sites in disordered loops, and affords a feasible way to develop these functional sites into opportunities for drug-resistance management.

Since the discovery of the first antibiotic, natural products have played an important role in chemistry, biology and medicine. To explore the potential of bioactive compounds from microbes isolated from the southeast of Tibet, China, a crude extract library was constructed and screened against Staphylococcus aureus. The strain Nocardiopsis sp. LS150010 was scaled up and subjected to further chemical studies, resulting in the identification of N-salicyloyl-2-aminopropan-1,3-diol (2) and its rare aziridine derivative, madurastatin B3 (1). Their structures were determined by detailed analysis of 1D, 2D NMR and HRMS data. Compounds 1 and 2 displayed significant inhibitory activity against S. aureus and methicillin resistant S. aureus, with MIC values of 6.25 µg/mL. Compound 1 also showed potent inhibitory activity against Bacillus subtilis and Escherichia coli, as well as activity in a Mycobacterium tuberculosis Bacillus Calmette-Guérin infected THP-1 cell model.