Understanding the different effects of fouling mechanisms on working and reference electrodes in fast-scan cyclic voltammetry for neurotransmitter detection.

Fast-scan cyclic voltammetry (FSCV) is a widely used technique for detecting neurotransmitters. However, electrode fouling can negatively impact its accuracy and sensitivity. Fouling refers to the accumulation of unwanted materials on the electrode surface, which can alter its electrochemical properties and reduce its sensitivity and selectivity. Fouling mechanisms can be broad and may include biofouling, the accumulation of biomolecules on the electrode surface, and chemical fouling, the deposition of unwanted chemical species. Despite individual studies discussing fouling effects on either the working electrode or the reference electrode, no comprehensive study has been conducted to compare the overall fouling effects on both electrodes in the context of FSCV. Here, we examined the effects of biofouling and chemical fouling on the carbon fiber micro-electrode (CFME) as the working electrode and the Ag/AgCl reference electrode with FSCV. Both fouling mechanisms significantly decreased the sensitivity and caused peak voltage shifts in the FSCV signal with the CFME, but not with the Ag/AgCl reference electrode. Interestingly, previous studies have reported peak voltage shifts in FSCV signals due to the fouling of Ag/AgCl electrodes after implantation in the brain. We noticed in a previous study that energy-dispersive spectroscopy (EDS) spectra showed increased sulfide ion concentration after implantation. We hypothesized that sulfide ions may be responsible for the peak voltage shift. To test this hypothesis, we added sulfide ions to the buffer solution, which decreased the open circuit potential of the Ag/AgCl electrode and caused a peak voltage shift in the FSCV voltammograms. Also, EDS analysis showed that sulfide ion concentration increased on the surface of the Ag/AgCl electrodes after 3 weeks of chronic implantation, necessitating consideration of sulfide ions as the fouling agent for the reference electrodes. Overall, our study provides important insights into the mechanisms of electrode fouling and its impact on FSCV measurements. These findings could inform the design of FSCV experiments, with the development of new strategies for improving the accuracy and reliability of FSCV measurements in vivo.

New Pimarane Diterpenoids Isolated from EtOAc-Extract of Apiospora arundinis Culture Medium Show Antibenign Prostatic Hyperplasia Potential.

Three new pimarane diterpenoids, libertellenones U-W (1-3), together with libertellenone C (4) and myrocin A (5) were isolated from an EtOAc-extract of Apiospora arundinis culture medium. The chemical structures of the new compounds were elucidated using MS, NMR, and CD spectroscopic data. Benign prostatic hyperplasia (BPH), the abnormal and pathological proliferation of epithelial and stromal cells in prostatic tissues, is a common disease in middle-aged and elderly men. In this study, the anti-BPH effects of myrocin A (5) were evaluated using BPH-1 and WPMY-1 cells. Treatment with myrocin A (5) exerted antiproliferative effects in BPH-1 and dihydrotestosterone (DHT)-stimulated WPMY-1 cells. In BPH, treatment with myrocin A (5) significantly suppressed the mRNA levels of androgen receptor (AR) and its downstream targets nuclear receptor coactivator 1 (NCOA1), proliferating cell nuclear antigen (PCNA) and kallikrein-related peptidase 3 (KLK3). Additionally, DHT-stimulated WPMY-1 cells demonstrated an upregulated mRNA levels of AR, NCOA1, PCNA, and KLK3. However, treatment with myrocin A (5) resulted in suppression of the mRNA levels. Moreover, myrocin A (5) docked computationally into the binding site of the androgen receptor (-5.5 kcal/mol).

New fusidane-type nortriterpenoids from the Arctic marine-derived fungus Simplicillium lamellicola culture medium with their inhibitory effect on benign prostatic hyperplasia.

Three new fusidane-type nortriterpenoids, simplifusinolide A, 24-epi simplifusinolide A, and simplifusidic acid L (1-3), were isolated from the EtOAc extract of the Arctic marine-derived fungus Simplicillium lamellicola culture medium, together with fusidic acid (4) and 16-O-deacetylfusicid acid (5). The structures of the isolated compounds were elucidated by NMR and MS analyses. The absolute configurations of compounds 1-3 were established by the quantum mechanical calculations of electronic circular dichroism and gauge-including atomic orbital NMR chemical shifts, followed by DP4 + analysis. Benign prostatic hyperplasia (BPH) is a major urological disorder in men worldwide. The anti-BPH potentials of the isolated compounds were evaluated using BPH-1 and WPMY-1 cells. Treatment with simplifusidic acid L (3) and fusidic acid (4) significantly downregulated the mRNA levels of the androgen receptor (AR) and its downstream effectors, inhibiting the proliferation of BPH-1 cells. Specifically, treatment with 24-epi simplifusinolide A (2) significantly suppressed the cell proliferation of both BPH-1 and DHT-stimulated WPMY-1 cells by inhibiting AR signaling. These results suggest the potential of 24-epi simplifusinolide A (2), simplifusidic acid L (3) and fusidic acid (4) as alternative agents for BPH treatment by targeting AR signaling.

Mass spectrometry-guided isolation of thiodiketopiperazines from an EtOAc-extract of Setosphaeria rostrata culture medium and their anti-skin aging effects on TNF-α-induced human dermal fibroblasts.

Using mass spectrometry (MS)-guided isolation methods, a new thiodiketopiperazine derivative (1) and exserohilone (2) were isolated from an EtOAc-extract of Setosphaeria rostrata culture medium. The chemical structure of the new compound was elucidated by MS and NMR spectroscopy, and the absolute configurations were established by the quantum mechanical calculations of electronic circular dichroism. All isolated compounds were examined for their effects on reactive oxygen species (ROS) production, matrix metalloproteinase 1 (MMP-1) secretion, and procollagen type I α1 secretion in tumor necrosis factor (TNF)-α-induced human dermal fibroblasts. Compound 1 and exserohilone (2) exhibited the inhibition of TNF-α-induced ROS generation and MMP-1 secretion. Additionally, compound 1 and exserohilone (2) increased the procollagen type I α1 secretion. Compound 1 docked computationally into the active site of MMP-1 (-6.0 kcal/mol).

Enhancing poly(3-hydroxybutyrate) production in halophilic bacteria through improved salt tolerance.

Polyhydroxyalkanoates (PHA) have emerged as a promising bio-compound in the industrial application due to their potential to replace conventional petroleum-based plastics with sustainable bioplastics. This study focuses on Halomonas sp. YJPS3-3, a halophilic bacterium, and presents a novel approach to enhance PHA production by exploiting its salt tolerance toward PHA biosynthesis. Through gamma irradiation-induced mutants with enhanced salt tolerance from 15% NaCl to 20% NaCl, mutant halo6 showing a significant 11% increase in PHA yield, was achieved. Moreover, the mutants displayed not only higher PHA content but also remarkable cell morphology with elongation. In addition, this research unravels the genetic determinants behind the elevated PHA content and identifies a corresponding shift in fatty acid composition favoring PHA accumulation. This novel mutant obtained from gamma irradiation with enhanced salt tolerance in halophilic bacteria opens up new avenues not only for the bioplastic industry but also for applications in the production of high-value metabolites.

Discovery of Bioactive Metabolites by Acidic Stress to a Geldanamycin Producer, Streptomyces samsunensis.

In an effort to activate silent biosynthetic gene clusters, Streptomyces samsunensis DSM42010, a producer of geldanamycin, was cultured at four different pHs (4.5, 5.4, 6.6, and 7.4). An acidic culture condition (pH 5.4) was selected for a chemical investigation since S. samsunensis showed a different metabolic profile compared to when it was cultured under other conditions. Seven new (1-7) and four known (8-11) compounds were isolated from these cultures. The structures of the isolated compounds were determined by spectroscopic techniques and chemical derivatization. Relative and absolute configurations of the new compounds (1-5) were established using JBCA, PGME method, advanced Marfey's method, modified Mosher's method, and comparison of observed and calculated ECD data. Interestingly, compounds 1-3 were truncated versions of geldanamycin, and compound 4 was also deduced to originate from geldanamycin. Compound 5 was composed of 3-methyltyrosine and 6-hydroxy-2,4-hexadienoic acid connected through an amide bond. Compounds 6 and 7 were dihydrogenated forms of geldanamycin with a hydroxy substitution. It is possible that culturing this strain under acidic conditions interfered to some degree with the geldanamycin polyketide synthase, leading to production of truncated versions as well as analogues of geldanamycin. Compounds 1, 8, and 9 showed significant antivirulence activity, inhibiting production of α-toxin by methicillin-resistant Staphylococcus aureus without growth attenuation and global regulatory inhibition; compounds 1, 8, and 9 may become promising α-toxin-specific antivirulence leads with less risk of resistance development.

Recombinant Lignin Peroxidase with Superior Thermal Stability and Melanin Decolorization Efficiency in a Typical Human Skin-Mimicking Environment.

Recently, the desire for a safe and effective method for skin whitening has been growing in the cosmetics industry. Commonly used tyrosinase-inhibiting chemical reagents exhibit side effects. Thus, recent studies have focused on performing melanin decolorization with enzymes as an alternative due to the low toxicity of enzymes and their ability to decolorize melanin selectively. Herein, 10 different isozymes were expressed as recombinant lignin peroxidases (LiPs) from Phanerochaete chrysosporium (PcLiPs), and PcLiP isozyme 4 (PcLiP04) was selected due to its high stability and activity at pH 5.5 and 37 °C, which is close to human skin conditions. In vitro melanin decolorization results indicated that PcLiP04 exhibited at least 2.9-fold higher efficiency than that of well-known lignin peroxidase (PcLiP01) in a typical human skin-mimicking environment. The interaction force between melanin films measured by a surface forces apparatus (SFA) revealed that the decolorization of melanin by PcLiP04 harbors a disrupted structure, possibly interrupting π-π stacking and/or hydrogen bonds. In addition, a 3D reconstructed human pigmented epidermis skin model showed a decrease in melanin area to 59.8% using PcLiP04, which suggests that PcLiP04 exhibits a strong potential for skin whitening.

Bioactive molecular network-guided discovery of dihydro-ß-agarofurans from the fruits of Celastrus orbiculatus.

A bioactive molecular networking strategy has been applied to discovery of bioactive constituents from the fruits of Celastrus orbiculatus Thunb., which showed significant inhibitory effects on the α-MSH-induced melanin production in B16F0 melanoma cells. In the obtained molecular network, the nodes with relatively high bioactive scores were prioritized for isolation; as a result, 12 undescribed dihydro-ß-agarofuran sesquiterpenes together with 15 known compounds were isolated from MeOH extracts of the fruits of C. orbiculatus. Their structures were elucidated based on the interpretation of NMR, HRESIMS, ECD data, and single crystal X-ray diffraction. Among the obtained isolates, celastorbin A and (1R,2S,4R,5S,7S,8S,9R,10S)-1,2,8-triacetoxy-9-cinnamoyloxydihydro-ß-agarofuran, which possessed high bioactive scores in the molecular network, exhibited potent inhibitory effects on the α-MSH-induced melanin production in B16F0 cells with IC50 values of 4.1 and 2.0 µM, respectively.

Citromycin Isolated from the Antarctic Marine-Derived Fungi, Sporothrix sp., Inhibits Ovarian Cancer Cell Invasion via Suppression of ERK Signaling.

Recently, microorganisms and their metabolites in the Antarctic marine environment have attracted attention as useful sources for novel therapeutics, including anticancer drugs. Here, we investigated the effects of citromycin, isolated from the Antarctic marine-derived fungus, Sporothrix sp., on human ovarian cancer cells. Citromycin inhibited the migration and invasion of human ovarian cancer SKOV3 and A2780 cells, but had no cytotoxic activity against them. Additionally, it inhibited the expression of epithelial-mesenchymal transition (EMT) markers and the activation of matrix metalloproteinase (MMP)-2 and MMP9. Moreover, extracellular signal-regulated kinase (ERK)-1/2 signaling was inhibited after citromycin treatment, and the ectopic expression of ERK negated the anti-invasive activity of citromycin. Our findings suggest that citromycin inhibits the migration and invasion of human ovarian cancer cells by downregulating the expression levels of EMT markers and MMP-2/9 via inhibition of the ERK1/2 pathway.

Top-down synthetic biology approach for titer improvement of clinically important antibiotic daptomycin in Streptomyces roseosporus.

Secondary metabolites are produced at low titers by native producers due to tight regulations of their productions in response to environmental conditions. Synthetic biology provides a rational engineering principle for transcriptional optimization of secondary metabolite BGCs (biosynthetic gene clusters). Here, we demonstrate the use of synthetic biology principles for the development of a high-titer strain of the clinically important antibiotic daptomycin. Due to the presence of large NRPS (non-ribosomal peptide synthetase) genes with multiple direct repeats, we employed a top-down approach that allows transcriptional optimization of genes in daptomycin BGC with the minimum inputs of synthetic DNAs. The repeat-free daptomycin BGC was created through partial codon-reprogramming of a NRPS gene and cloned into a shuttle BAC vector, allowing BGC refactoring in a host with a powerful recombination system. Then, transcriptions of functionally divided operons were sequentially optimized through three rounds of DBTL (design-build-test-learn) cycles that resulted in up to ~2300% improvement in total lipopeptide titers compared to the wild-type strain. Upon decanoic acid feeding, daptomycin accounted for ∼ 40% of total lipopeptide production. To the best of our knowledge, this is the highest improvement of daptomycin titer ever achieved through genetic engineering of S. roseosporus. The top-down engineering approach we describe here could be used as a general strategy for the development of high-titer industrial strains of secondary metabolites produced by BGCs containing genes of large multi-modular NRPS and PKS enzymes.

PTP1B Inhibitory Secondary Metabolites from an Antarctic Fungal Strain Acremonium sp. SF-7394.

Chemical investigation of the Antarctic lichen-derived fungal strain Acremonium sp. SF-7394 yielded a new amphilectane-type diterpene, acrepseudoterin (1), and a new acorane-type sesquiterpene glycoside, isocordycepoloside A (2). In addition, three known fungal metabolites, (-)-ternatin (3), [D-Leu]-ternatin (4), and pseurotin A (5), were isolated from the EtOAc extract of the fungal strain. Their structures were mainly elucidated by analyzing their NMR and MS data. The absolute configuration of 1 was proposed by electronic circular dichroism calculations, and the absolute configuration of the sugar unit in 2 was determined by a chemical method. The inhibitory effects of the isolated compounds on protein tyrosine phosphatase 1B (PTP1B) were evaluated by enzymatic assays; results indicated that acrepseudoterin (1) and [D-Leu]-ternatin (4) dose-dependently inhibited the enzyme activity with IC50 values of 22.8 ± 1.1 µM and 14.8 ± 0.3 µM, respectively. Moreover, compound 1 was identified as a competitive inhibitor of PTP1B.

A new α-pyrone from Arthrinium pseudosinense culture medium and its estrogenic activity in MCF-7 cells.

A new α-pyrone analog, arthrifuranone A (1) was isolated from an EtOAc-extract of Arthrinium pseudosinense culture medium. The isolation workflow was guided by a Molecular Networking-based dereplication strategy. The chemical structure of the new compound was elucidated using MS and NMR spectroscopic techniques, and the absolute configuration was established by the Mosher's method and gauge-including atomic orbital NMR chemical shift calculations, followed by DP4 + analysis. The isolated compound was evaluated for its estrogenic activity using the MCF-7 estrogen responsive human breast cancer cells. Compound 1 showed estrogenic activity by increasing the proliferation of MCF-7 cells at the concentration of 3.125 µM via phosphorylation of estrogen receptor-α.

Anti-inflammatory spiroditerpenoids from Penicillium bialowiezense.

Inflammation is a vital process that maintains tissue homeostasis. However, it is widely known that uncontrolled inflammation can contribute to the development of various diseases. This study aimed to discover anti-inflammatory metabolites from Penicillium bialowiezense. Seven spiroditerpenoids, including two new compounds, breviones P and Q (1 and 2), were isolated and characterized by various spectroscopic and spectrometric methods. All isolated compounds were initially tested for their inhibitory effects against lipopolysaccharide-induced nitric oxide (NO) production in RAW 264.7 macrophages. Of these, brevione A (3) exhibited this activity with a half-maximal inhibitory concentration value of 9.5 µM. Further mechanistic studies demonstrated that 3 could suppress the expression of pro-inflammatory cytokines and mediators, such as NO, prostaglandin E2, interleukin (IL)-1ß, tumor necrosis factor-α, IL-6, and IL-12 by inhibiting the activation of nuclear factor-kappa B and c-Jun N-terminal kinase.

Chemical constituents from basidiomycete Basidioradulum radula culture medium and their cytotoxic effect on human prostate cancer DU-145 cells.

Eight new naphtho[1,2-c]furan derivatives (1-8) along with six known analogues (9-14) were isolated from culture medium of the basidiomycete Basidioradulum radula. The structures of these compounds were identified using spectroscopic analysis, and their absolute configurations were resolved using X-ray diffraction, ECD, and VCD. Compounds 7 and 14 inhibited the cell viability of human prostate cancer DU-145 cells with IC50 values of 7.54 ± 0.03 µM and 5.04 ± 0.03 µM, respectively. At 8 µM, compounds 7 and 14 increased the percentage of apoptotic cells and upregulated the protein expression related to the apoptosis caspase pathways in DU-145 cells. Furthermore, the hallmarks of cells undergoing apoptosis, such as chromatin condensation, were also observed at this concentration. However, compound 7 and 14 showed no effect on the proliferation of splenocytes isolated from cyclophosphamide-induce immunosuppressed mice.

Total Synthesis of the Neuroprotective Agent Cudraisoflavone J.

Cudraisoflavone J (1), isolated from Cudrania tricuspidata, is a potent neuroprotective compound with a chiral center. Herein, we report the first total synthesis of racemic cudraisoflavone J (1) using a Claisen rearrangement and a Suzuki coupling reaction as the key steps. Racemic secondary alcohol was kinetically resolved to give (+)- and (-)-cudraisoflavone J with up to 97 and 88% enantiomeric excess, respectively. The modified Mosher's method was used to elucidate the absolute configuration of naturally occurring cudraisoflavone J.

Sesquiterpenoids from Chrysanthemum indicum with Inhibitory Effects on NO Production.

Three new guaianolide lactones (1-3) and four new 9-oxonerolidol glucosides (5-8) together with 20 known compounds were isolated from the MeOH extract of the flowers of Chrysanthemum indicum. Their structures were elucidated based on the interpretation of NMR, HRESIMS, and electronic circular dichroism (ECD) data along with acid hydrolysis. Of the isolates, sesquiterpenoids 1-4 and 15 and flavones 17 and 18 exhibited inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide production in RAW 264.7 cells with IC50 values in the range 0.2-27.0 µM.

Diterpenoids and Diacetylenes from the Roots of Aralia cordata with Inhibitory Effects on Nitric Oxide Production.

Bioactivity-guided isolation of a MeOH extract of Aralia cordata led to the isolation of four new ent-pimarane diterpenoids (1-4) and a diacetylene (5) together with 21 known compounds (6-26). Their structures were established based on the interpretation of one- and two-dimensional NMR and HRESIMS data. The absolute configurations of the new isolates were determined by electronic circular dichroism data analysis, single crystal X-ray diffraction, and Mosher's esterification method. All compounds exhibited inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages with IC50 values ranging from 1.1 to 69.4 µM.

Antioxidant and Antidiabetic Activities of Flavonoid Derivatives from the Outer Skins of Allium cepa L.

The onion, known as the bulb onion or common onion, is not only a key ingredient in many tasty and healthy vegetarian meals but also many traditional medicines. Nine new flavonoids [cepaflavas A, B (5, 6), cepadials A-D (7-9 and 14), and cepabiflas A-C (10-12)] and six known compounds (1-4, 13, 15) were obtained from the outer skins of Allium cepa L. Among them, compounds 5, 6, and 9 might be artificial products formed during extraction and isolation. New compounds were structurally elucidated using various spectroscopy/spectrometry techniques, including NMR and HRMS, and computational methods. Their absolute configurations were determined using time-dependent density functional theory calculations, combined with ECD spectroscopy, optical rotation calculation, and statistical procedures (CP3 and DP4 analysis). The free radical scavenging assays revealed that the new compounds 10-12 possessed considerable antioxidant activities with IC50 values of 4.25-8.88 and 7.12-8.14 µM against DPPH and ABTS•+, respectively. Compounds 13-15 showed substantial inhibitory activities against both α-glucosidase and protein tyrosine phosphatase 1B (PTP1B), with IC50 values of 0.89-6.80 and 1.13-6.82 µM, respectively. On the basis of molecular docking studies, 13 and 15 were predicted to have high binding capacity and strong affinity toward the active site of PTP1B.

Anti-inflammatory Metabolites from Chaetomium nigricolor.

Twelve metabolites were obtained from the culture media of Chaetomium nigricolor, including a new furan derivative, methyl succinyl Sumiki's acid (1), and two new atropisomers of the previously reported bis-naphtho-γ-pyrones, (aS)-asperpyrone A and (aS)-fonsecinone A (2 and 3). The structures were elucidated by spectroscopic, chemical, and chiroptical techniques. Compounds 2 and 3 inhibited nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 macrophages. Compound 2 was found to inhibit nuclear factor-kappa B and c-Jun N-terminal kinase activation, in turn suppressing pro-inflammatory mediators and cytokines including nitric oxide, prostaglandin E2, interleukin (IL)-1ß, tumor necrosis factor-α, IL-6, and IL-12.

An Efficient Amphiphilic-Type Triphenylamine-Based Organic Hole Transport Material for High-Performance and Ambient-Stable Dopant-Free Perovskite and Organic Solar Cells.

A new set of simply structured triphenylamine-based small molecules are synthesized and evaluated as dopant-free hole transporting materials (HTMs) for high-performance perovskite solar cells (PSCs) and bulk heterojunction inverted organic solar cells (BHJ IOSCs). Surprisingly, the new amphiphilic-type HTM-1 (with internal hydrophilic groups and peripheral hydrophobic alkyl tails) showed better compatibility and performance than the actual target molecule, that is, HTM-2 in PSCs and BHJ IOSCs. Importantly, the HTM-1-based dopant-free PSCs and BHJ IOSCs exhibited high power conversion efficiencies (PCEs) of 11.45 % and 8.34 %, respectively. These performances are superior and comparable to those of standard HTMs Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene) and PEDOT:PSS (poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate) in PSCs and BHJ IOSCs, respectively. The enhanced device performance of the HTM-1-based PSCs is ascribed to its strong affinity towards the perovskite, properly aligned energy levels with respect to the perovskite valence band, and excellent hole transporting behavior. In addition, the well-organized energy levels of the HTMs showed excellent compatibility in BHJ IOSCs. The new amphiphilic-type HTM-based photovoltaic devices also showed long-term air stability over 700 h. These promising results offer new and unexpected prospects for engineering the interface between the photoactive material and HTMs in PSCs and BHJ IOSCs.