In silico prediction of polyketide biosynthetic gene clusters in the genomes of Hypericum-borne endophytic fungi.

BACKGROUND: The search for new bioactive natural compounds with anticancer activity is still of great importance. Even though their potential for diagnostics and treatment of cancer has already been proved, the availability is still limited. Hypericin, a naphthodianthrone isolated essentially from plant source Hypericum perforatum L. along with other related anthraquinones and bisanthraquinones belongs to this group of compounds. Although it has been proven that hypericin is synthesized by the polyketide pathway in plants, none of the candidate genes coding for key enzymes has been experimentally validated yet. Despite the rare occurrence of anthraquinones in plants, their presence in microorganisms, including endophytic fungi, is quite common. Unlike plants, several biosynthetic genes grouped into clusters (BGCs) in fungal endophytes have already been characterized. RESULTS: The aim of this work was to predict, identify and characterize the anthraquinone BGCs in de novo assembled and functionally annotated genomes of selected endophytic fungal isolates (Fusarium oxysporum, Plectosphaerella cucumerina, Scedosporium apiospermum, Diaporthe eres, Canariomyces subthermophilus) obtained from different tissues of Hypericum spp. The number of predicted type I polyketide synthase (PKS) BGCs in the studied genomes varied. The non-reducing type I PKS lacking thioesterase domain and adjacent discrete gene encoding protein with product release function were identified only in the genomes of C. subthermophilus and D. eres. A candidate bisanthraquinone BGC was predicted in C. subthermophilus genome and comprised genes coding the enzymes that catalyze formation of the basic anthraquinone skeleton (PKS, metallo-beta-lactamase, decarboxylase, anthrone oxygenase), putative dimerization enzyme (cytochrome P450 monooxygenase), other tailoring enzymes (oxidoreductase, dehydrogenase/reductase), and non-catalytic proteins (fungal transcription factor, transporter protein). CONCLUSIONS: The results provide an insight into genetic background of anthraquinone biosynthesis in Hypericum-borne endophytes. The predicted bisanthraquinone gene cluster represents a basis for functional validation of the candidate biosynthetic genes in a simple eukaryotic system as a prospective biotechnological alternative for production of hypericin and related bioactive anthraquinones.

Potential-Resolved Ratio Electrochemiluminescence Biosensor Based on Perylene Diimide-MOF and DNA Nanoflowers-CdS Quantum Dots for Detection of Dual Targets.

BRCA1 gene and carcinoembryonic antigen (CEA) are important markers of breast cancer, so accurate detection of them is significant for early detection and diagnosis of breast cancer. In this study, a potential-resolved ratio electrochemiluminescence (ECL) biosensor using perylene diimide (PDI)-metal-organic framework and DNA nanoflowers (NFs)-CdS quantum dots (QDs) was constructed for detection of BRCA1 and CEA. Specifically, PDI-MOF and CdS QDs can generate potential-resolved intense ECL signals only using one coreactant, so the detection procedure can be effectively simplified. PDI-MOF was first attached to the electrode by graphene oxide, and the dopamine (DA) probe was linked to quench the ECL signal by DNA hybridization. In the presence of target BRCA1, it can form a bipedal DNA walker, so the quenching molecules (DA) were detached from the electrode via the walker amplification process aided by Mg2+, so that the PDI signal at -0.25 V was restored for the BRCA1 assay. Moreover, CdS QDs@DNA NFs as amplified signal probes were formed by self-assembly, and the target CEA-amplified product introduced the CdS QDs@DNA NFs to the electrode, so the QD ECL signal at -1.42 V was enhanced, while the ECL signal of PDI is unchanged; thus, CEA detection was achieved by the ratio value between them. Therefore, the detection accuracy is guaranteed by detection of two cancer markers and a ratio value. This biosensor has a great contribution to the development of new ECL materials and a novel ECL technique for fast and efficient multitarget assays, showing great significance for the early monitoring and diagnosis of breast cancer.

A Self-Assembly-Induced Exciton Delocalization Strategy for Converting a Perylene Diimide Derivative from a Type-II to Type-I Photosensitizer.

Type-I photosensitizers have shown advantages in addressing the shortcomings of traditional oxygen-dependent type-II photosensitizers for the photodynamic therapy (PDT) of hypoxic tumors. However, developing type-I photosensitizers is yet a huge challenge because the type-II energy transfer process is much faster than the type-I electron transfer process. Herein, from the fundamental point of view, an effective approach is proposed to improve the electron transfer efficiency of the photosensitizer by lowering the internal reorganization energy and exciton binding energy via self-assembly-induced exciton delocalization. An example proof is presented by the design of a perylene diimide (PDI)-based photosensitizer (PDIMp) that can generate singlet oxygen (1O2) via a type-II energy transfer process in the monomeric state, but induce the generation of superoxide anion (O2˙-) via a type-I electron transfer process in the aggregated state. Significantly, with the addition ofcucurbit[6]uril (CB[6]), the self-assembled PDIMp can convert back to the monomeric state via host-guest complexation and consequently recover the generation of 1O2. The biological evaluations reveal that supramolecular nanoparticles (PDIMp-NPs) derived from PDIMp show superior phototherapeutic performance via synergistic type-I PDT and mild photothermal therapy (PTT) against cancer under either normoxia or hypoxia conditions.

Brain-Targeted Black Phosphorus-Based Nanotherapeutic Platform for Enhanced Hypericin Delivery in Depression.

Depression is a significant global health concern that remains inadequately treated due to the limited effectiveness of conventional drug therapies. One potential therapeutic agent, hypericin (HYP), is identified as an effective natural antidepressant. However, its poor water solubility, low bioavailability, and limited ability to penetrate the brain parenchyma have hindered its clinical application. To address these shortcomings and enhance the therapeutic efficacy of HYP, it is loaded onto black phosphorus nanosheets (BP) modified with the neural cell-targeting peptide RVG29 to synthesize a nanoplatform named BP-RVG29@HYP (BRH). This platform served as a nanocarrier for HYP and integrated the advantages of BP with advanced delivery methods and precise targeting strategies. Under the influence of 808 nm near-infrared irradiation (NIR), BRH effectively traversed an in vitro BBB model. In vivo experiments validated these findings, demonstrating that treatment with BRH significantly alleviated depressive-like behaviors and oxidative stress in mice. Importantly, BRH exhibited an excellent safety profile, causing minimal adverse effects, which highlighted its potential as a promising therapeutic agent. In brief, this novel nanocarrier holds great promise in the development of antidepressant drugs and can create new avenues for the treatment of depression.

Aryne Atropisomers: Chiral Arynes for the Enantiospecific Synthesis of Atropisomers and Nanographene Atropisomers.

The basics about arynes and their applications in synthetic organic chemistry are briefly presented, and the concept of atropisomerism is defined, highlighting that it is a time-dependent form of isomerism and chirality. It is remembered that racemization is a macroscopic and statistical irreversible process, while enantiomerization is a nanoscopic reversible process that occurs at the molecular scale, with racemization being twice as fast as enantiomerization. The concept of aryne atropisomers is introduced with a naive question: Can synthetically useful nonracemic aryne atropisomers having a triple bond ortho to the stereogenic single bond exist in solution? It was found that such aryne atropisomers can be generated in solution from easily available ortho-iodoaryl triflate precursors and excess trimethylsilylmethylmagnesium chloride. Analysis of the barriers to enantiomerization of some aryne atropisomers by computational modeling revealed the key contribution to the configurational stability of the H atom in tris-ortho-substituted biphenyl-based atropisomers. Using a specially designed prototype of aryne atropisomer, for which the barrier to enantiomerization was accurately evaluated by advanced computational modeling, the kinetic parameters of its reaction with furan were experimentally determined. From these measurements, it was concluded that any aryne atropisomer with a barrier to enantiomerization ΔGenant⧧ equal to or higher than 50 kJ mol-1 would lead to fully enantiospecific reactions. The synthetic applications of two structurally distinct aryne atropisomers built on a 1-phenylnaphthalene platform are described: one has the aryne triple bond embedded in the naphthyl moiety, and the other has the aryne triple bond embedded in the phenyl moiety. Both aryne atropisomers allowed for the fully enantiospecific, and possibly overall enantioselective, syntheses of original atropisomers based on standard aryne chemistry. For instance, reactions with anthracene and perylene afforded triptycene and nanographene atropisomers, respectively, in high enantiomeric excesses. A bis(aryne) atropisomer synthetic equivalent prepared from either enantiomer of BINOL is described for 3D bidirectional reactions with a single handedness. Its 2-fold reactions with anthracene and perylene afforded the corresponding severely congested bis(benzotriptycene) (99% ee) nanocarbon atropisomer and bis(anthra[1,2,3,4-ghi]perylene) (98% ee) nanographene atropisomer, respectively. This allowed the discovery of bis(twistacene) atropisomers as a new class of polycyclic aromatic hydrocarbons (PAH) with multiple stereogenicities. Cross reactions with the bis(aryne) atropisomer synthetic equivalent and two different arynophiles proved feasible, providing a nanographene atropisomer with a benzotriptycene unit and an anthra[1,2,3,4-ghi]perylene unit assembled around a stereogenic axis as a unique chiral PAH (99% ee). Overall, because the concept is simple and its implementation is easy, aryne atropisomers is an attractive approach to the synthesis of atropisomers in a broad meaning. Applications to the synthesis of large PAH atropisomers with single handedness are particularly promising.

Hypericin Alleviates Chronic Kidney Disease-induced Left Ventricular Hypertrophy by Regulation of FGF23-FGFR4 Signaling Pathway.

ABSTRACT: Chronic kidney disease (CKD) is a significant global health threat that imposes a substantial burden on both individuals and societies. CKD frequently correlates with cardiovascular events, particularly left ventricular hypertrophy (LVH), which contributes to the high mortality rate associated with CKD. Fibroblast growth factor 23 (FGF23), a hormone primarily involved in regulating calcium and phosphorus metabolism, has been identified as a major risk factor for LVH in CKD patients. Elevated serum FGF23 levels are known to induce LVH and myocardial fibrosis by activating the fibroblast growth factor receptor 4 (FGFR4) signal pathway. Therefore, targeting FGFR4 and its downstream signaling pathways holds potential as a treatment strategy for cardiac dysfunction in CKD. In our current study, we have discovered that Hypericin, a key component derived from Hypericum perforatum , has the ability to alleviate CKD-related LVH by targeting the FGFR4/phospholipase C gamma 1 (PLCγ1) signaling pathway. Through in vitro experiments using rat cardiac myocyte H9c2 cells, we observed that Hypericin effectively inhibits FGF23-induced hypertrophy and fibrosis by suppressing the FGFR4/PLCγ1/calcineurin/nuclear factor of activated T-cell (NFAT3) signaling pathway. In addition, our in vivo studies using mice on a high-phosphate diet and rat models of 5/6 nephrectomy demonstrated that Hypericin has therapeutic effects against CKD-induced LVH by modulating the FGFR4/PLCγ1/calcineurin/NFAT3 signaling pathway. In conclusion, our research highlights the potential of Hypericin as a candidate for the treatment of CKD-induced cardiomyopathy. By suppressing the FGFR4/PLCγ1 signaling pathway, Hypericin shows promise in attenuating LVH and myocardial fibrosis associated with CKD.

The contradictory role of febuxostat in ABCG2 expression and potentiating hypericin-mediated photodynamic therapy in colorectal cancers.

Photodynamic Therapy (PDT) is an emerging method to treat colorectal cancers (CRC). Hypericin (HYP) is an effective mediator of PDT and the ABCG2 inhibitor, Febuxostat (FBX) could augment PDT. HT29 and HEK293 cells showed light dependant cytotoxic response to PDT in both 2D and 3D cell models. FBX co-treatment was not found to improve PDT cytotoxicity. Next, ABCG2 protein expression was observed in HT29 but not in HEK293 cells. However, ABCG2 gene expression analysis did not support protein expression results as ABCG2 gene expression results were found to be higher in HEK293 cells. Although HYP treatment was found to significantly reduce ABCG2 gene expression levels in both cell lines, FBX treatment partially restored ABCG2 gene expression. Our findings indicate that FBX co-treatment may not be suitable for augmenting HYP-mediated PDT in CRC but could potentially be useful for other applications.

Hypericin-mediated photodynamic therapy inhibits metastasis and EMT of colorectal cancer cells by regulating RhoA-ROCK1 signaling pathway.

Colorectal cancer (CRC) is significantly contributed to global cancer mortality rates. Treating CRC is particularly challenging due to metastasis and drug resistance. There is a pressing need for new treatment strategies against metastatic CRC. Photodynamic therapy (PDT) offers a well-established, minimally invasive treatment option for cancer with limited side effects. Hypericin (HYP), a potent photosensitizer for PDT, has been documented to induce cytotoxicity and apoptosis in various types of cancers. However, there are few reports on the inhibitory effects of HYP-mediated PDT on the metastatic ability of CRC cells. Here, we evaluate the inhibitory effects of HYP-mediated PDT against metastatic CRC cells and define its underlying mechanisms. Wound-healing and Transwell assays show that HYP-mediated PDT suppresses migration and invasion of CRC cells. F-actin visualization assays indicate HYP-mediated PDT decreases F-actin formation in CRC cells. TEM assays reveal HYP-mediated PDT disrupts pseudopodia formation of CRC cells. Mechanistically, immunofluorescence and western blotting results show that HYP-mediated PDT upregulates E-cadherin and downregulates N-cadherin and Vimentin. HYP-mediated PDT also suppresses key EMT regulators, including Snail, MMP9, ZEB1 and α-SMA. Additionally, the expressions of RhoA and ROCK1 are downregulated by HYP-mediated PDT. Together, these findings suggest that HYP-mediated PDT inhibits the migration and invasion of HCT116 and SW620 cells by modulating EMT and RhoA-ROCK1 signaling pathway. Thus, HYP-mediated PDT presents a potential therapeutic option for CRC.

A perylene diimide electrochemical probe with persulfate as a signal enhancer for dopamine sensing.

Dopamine (DA) is an important biomarker related to parkinsonism, schizophrenia and renal disease. Traditional electrochemical sensors for DA were based on the direct electrochemical oxidation of DA. In this paper, we report a new sensing strategy using N,N'-di(trimethylaminoethyl)perylene diimide (TMPDI) as an electrochemical probe and K2S2O8 as a signal enhancer for DA detection between 0 and -0.7 V with the DPV technique. MoS2 nanoflowers prepared by the hydrothermal method were used as a nanocarrier to load TMPDI. The reduction current of TMPDI was found to show a stepwise and significant increase at -0.24 V with the increase of concentration of K2S2O8 due to the continuous cycle of TMPDI molecules' electrochemical reduction and chemical oxidation. The presence of DA caused a large decrease of the reduction current of TMPDI due to the synergistic interaction of the competitive consumption of DA for K2S2O8 and the blocking effect of polyDA adhering to the electrode surface. The decreased current exhibited a linear response for DA from 10 pM to 100 µM with a detection limit of 4.1 pM and the proposed sensor showed high selectivity and excellent feasibility in human urine/serum sample detection.

Supersensitive detection of lincomycin with an ECL aptasensor based on the synergistic integration of gold-functionalized upconversion nanoparticles and thiolated 3,4,9,10-perylene tetracarboxylic acid.

In this work, the supersensitive and selective determination of lincomycin (Lin) was achieved using a novel electroluminescent (ECL) aptasensor based on the synergistic integration of gold functionalized upconversion nanoparticles (UCNPs) and thiolated 3,4,9,10-perylene tetracarboxylic acid (PTCA). The integration of two luminophores of UCNPs and PTCA combined the merits of the cathodoluminescence stability of UCNPs and the high quantum yield of PTCA, which significantly promoted the ECL signal and analytical performance of the proposed sensor. The introduction of gold nanoparticles in UCNPs can not only improve the conductivity and ECL performance of UCNPs but also cause them to easily integrate with thiolated PTCA (t-PTCA) via an Au-S bond. The ECL signal of UCNPs@Au/t-PTCA/GCE was almost twice as strong as that of t-PTCA/GCE and tenfold higher than that of UCNPs@Au/GCE. Because of the non-conductive protein of the Lin aptamer, the ECL intensity of apt/UCNPs@Au/t-PTCA/GCE noticeably decreased. In the presence of Lin, the aptamer was pulled down from the sensing interface, resulting in the recovery of the ECL intensity of the sensor. Under optimal conditions, our proposed sensor can quantify the concentration of Lin in the range from 1.0 × 10-15 to 1.0 × 10-7 M with a low detection limit of 2.4 × 10-16 M (S/N = 3), exhibiting high sensitivity and specificity for the determination of Lin.

A novel photosensitizer based on hypocrellin B activated by cysteine over-expressed in cancer cells.

L-Cysteine (Cys)-activatable photosensitizer 3 was designed and synthesized based on hypocrellin B (1). Cys is a novel tumor-associated biomarker. 3 exhibited negligible photosensitizing ability without Cys. However, when 1 was released from 3 by reaction with Cys, the photosensitizing activity was restored. Furthermore, 3 showed selective and effective photo-cytotoxicity against only cancer cells such as HeLa and A549 cells that highly express Cys when irradiated with 660 nm light, which is inside the phototherapeutic window.

Heat stress-induced NO enhanced perylenequinone biosynthesis of Shiraia sp. via calcium signaling pathway.

Perylenequinones (PQs) are natural photosensitizing compounds used as photodynamic therapy, and heat stress (HS) is the main limiting factor of mycelial growth and secondary metabolism of fungi. This study aimed to unravel the impact of HS-induced Ca2+ and the calcium signaling pathway on PQ biosynthesis of Shiraia sp. Slf14(w). Meanwhile, the intricate interplay between HS-induced NO and Ca2+ and the calcium signaling pathway was investigated. The outcomes disclosed that Ca2+ and the calcium signaling pathway activated by HS could effectively enhance the production of PQs in Shiraia sp. Slf14(w). Further investigations elucidated the specific mechanism through which NO signaling molecules induced by HS act upon the Ca2+/CaM (calmodulin) signaling pathway, thus propelling PQ biosynthesis in Shiraia sp. Slf14(w). This was substantiated by decoding the downstream positioning of the CaM/CaN (calcineurin) pathway in relation to NO through comprehensive analyses encompassing transcript levels, enzyme assays, and the introduction of chemical agents. Concurrently, the engagement of Ca2+ and the calcium signaling pathway in heat shock signaling was also evidenced. The implications of our study underscore the pivotal role of HS-induced Ca2+ and the calcium signaling pathway, which not only participate in heat shock signal transduction but also play an instrumental role in promoting PQ biosynthesis. Consequently, our study not only enriches our comprehension of the mechanisms driving HS signaling transduction in fungi but also offers novel insights into the PQ synthesis paradigm within Shiraia sp. Slf14(w). KEY POINTS: • The calcium signaling pathway was proposed to participate in PQ biosynthesis under HS. • HS-induced NO was revealed to act upon the calcium signaling pathway for the first time.

Distribution and Sequestration of Cercosporin by Cercospora cf. flagellaris.

Plant-pathogenic fungi produce toxins as virulence factors in many plant diseases. In Cercospora leaf blight of soybean caused by Cercospora cf. flagellaris, symptoms are a consequence of the production of a perylenequinone toxin, cercosporin, which is light-activated to produce damaging reactive oxygen species. Cercosporin is universally toxic to cells, except to the cells of the producer. The current model of self-resistance to cercosporin is largely attributed to the maintenance of cercosporin in a chemically reduced state inside hyphae, unassociated with cellular organelles. However, in another perylenequinone-producing fungus, Phaeosphaeria sp., the toxin was specifically sequestered inside lipid droplets (LDs) to prevent reactive oxygen species production. This study hypothesized that LD-based sequestration of cercosporin occurred in C. cf. flagellaris and that lipid-inhibiting fungicides could inhibit toxin production. Confocal microscopy using light-cultured C. cf. flagellaris indicated that 3-day-old hyphae contained two forms of cercosporin distributed in two types of hyphae. Reduced cercosporin was uniformly distributed in the cytoplasm of thick, primary hyphae, and, contrary to previous studies, active cercosporin was observed specifically in the LDs of thin, secondary hyphae. The production of hyphae of two different thicknesses, a characteristic of hemibiotrophic plant pathogens, has not been documented in C. cf. flagellaris. No correlation was observed between cercosporin production and total lipid extracted, and two lipid-inhibiting fungicides had little effect on fungal growth in growth-inhibition assays. This study lays a foundation for exploring the importance of pathogen lifestyle, toxin production, and LD content in the pathogenicity and symptomology of Cercospora.

Hazard characterization of Alternaria toxins to identify data gaps and improve risk assessment for human health.

Fungi of the genus Alternaria are ubiquitous plant pathogens and saprophytes which are able to grow under varying temperature and moisture conditions as well as on a large range of substrates. A spectrum of structurally diverse secondary metabolites with toxic potential has been identified, but occurrence and relative proportion of the different metabolites in complex mixtures depend on strain, substrate, and growth conditions. This review compiles the available knowledge on hazard identification and characterization of Alternaria toxins. Alternariol (AOH), its monomethylether AME and the perylene quinones altertoxin I (ATX-I), ATX-II, ATX-III, alterperylenol (ALP), and stemphyltoxin III (STTX-III) showed in vitro genotoxic and mutagenic properties. Of all identified Alternaria toxins, the epoxide-bearing analogs ATX-II, ATX-III, and STTX-III show the highest cytotoxic, genotoxic, and mutagenic potential in vitro. Under hormone-sensitive conditions, AOH and AME act as moderate xenoestrogens, but in silico modeling predicts further Alternaria toxins as potential estrogenic factors. Recent studies indicate also an immunosuppressive role of AOH and ATX-II; however, no data are available for the majority of Alternaria toxins. Overall, hazard characterization of Alternaria toxins focused, so far, primarily on the commercially available dibenzo-α-pyrones AOH and AME and tenuazonic acid (TeA). Limited data sets are available for altersetin (ALS), altenuene (ALT), and tentoxin (TEN). The occurrence and toxicological relevance of perylene quinone-based Alternaria toxins still remain to be fully elucidated. We identified data gaps on hazard identification and characterization crucial to improve risk assessment of Alternaria mycotoxins for consumers and occupationally exposed workers.

Role of intramolecular hydrogen bonds in promoting electron flow through amino acid and oligopeptide conjugates.

Elucidating the factors that control charge transfer rates in relatively flexible conjugates is of importance for understanding energy flows in biology as well as assisting the design and construction of electronic devices. Here, we report ultrafast electron transfer (ET) and hole transfer (HT) between a corrole (Cor) donor linked to a perylene-diimide (PDI) acceptor by a tetrameric alanine (Ala)4 Selective photoexcitation of the donor and acceptor triggers subpicosecond and picosecond ET and HT. Replacement of the (Ala)4 linker with either a single alanine or phenylalanine does not substantially affect the ET and HT kinetics. We infer that electronic coupling in these reactions is not mediated by tetrapeptide backbone nor by direct donor-acceptor interactions. Employing a combination of NMR, circular dichroism, and computational studies, we show that intramolecular hydrogen bonding brings the donor and the acceptor into proximity in a "scorpion-shaped" molecular architecture, thereby accounting for the unusually high ET and HT rates. Photoinduced charge transfer relies on a (Cor)NH…O=C-NH…O=C(PDI) electronic-coupling pathway involving two pivotal hydrogen bonds and a central amide group as a mediator. Our work provides guidelines for construction of effective donor-acceptor assemblies linked by long flexible bridges as well as insights into structural motifs for mediating ET and HT in proteins.

Diesters of monoimide of perylene-3,4,9,10-tetracarboxylic acid - Synthesis, characterization, and application for dyeing polyester fibre, polystyrene, and poly (methyl methacrylate) films.

Three dyes-diesters of monoimides of perylene-3,4,9,10-tetracarboxylic acid were synthesized in three-stage process: esterification, hydrolysis, and monoimidation as potential fluorescent light-stable colorants for high visibility safety wear. The structure of these compounds was confirmed by 1H nuclear magnetic resonance spectroscopy and mass spectrometry, and their spectroscopic and physicochemical properties were determined. Colorants were applied to dyeing polyester fibre and polystyrene and poly (methyl methacrylate) films. The light, wash, and rubbing fastness of the dyeings were determined, and chromaticity coordinates were measured and discussed.

Development of a sensitive electrochemical method to determine amitraz based on perylene tetracarboxylic acid/mesoporous carbon/Nafion@SPCEs.

A cutting-edge electrochemical method is presented for precise quantification of amitraz (AMZ), a commonly used acaricide in veterinary medicine and agriculture. Leveraging a lab-made screen-printed carbon electrode modified with a synergistic blend of perylene tetracarboxylic acid (PTCA), mesoporous carbon (MC), and Nafion, the sensor's sensitivity was significantly improved. Fine-tuning of PTCA, MC, and Nafion ratios, alongside optimization of the pH of the supporting electrolyte and accumulation time, resulted in remarkable sensitivity enhancements. The sensor exhibited a linear response within the concentration range 0.01 to 0.70 µg mL-1, boasting an exceptionally low limit of detection of 0.002 µg mL-1 and a limit of quantification of 0.10 µg mL-1, surpassing maximum residue levels permitted in honey, tomato, and longan samples. Validation with real samples demonstrated high recoveries ranging from 80.8 to 104.8%, with a relative standard deviation below 10%, affirming the method's robustness and precision. The modified PTCA/MC/Nafion@SPCE-based electrochemical sensor not only offers superior sensitivity but also simplicity and cost-effectiveness, making it a pivotal tool for accurate AMZ detection in food samples. Furthermore, beyond the scope of this study, the sensor presents promising prospects for wider application across various electrochemical analytical fields, thereby significantly contributing to food safety and advancing agricultural practices.

Using Hybrid PDI-Fe3O4 Nanoparticles for Capturing Aliphatic Alcohols: Halogen Bonding vs. Lone Pair-π Interactions.

In this study, Fe3O4 nanoparticles (FeNPs) decorated with halogenated perylene diimides (PDIs) have been used for capturing VOCs (volatile organic compounds) through noncovalent binding. Concretely, we have used tetrachlorinated/brominated PDIs as well as a nonhalogenated PDI as a reference system. On the other hand, methanol, ethanol, propanol, and butanol were used as VOCs. Experimental studies along with theoretical calculations (the BP86-D3/def2-TZVPP level of theory) pointed to two possible and likely competitive binding modes (lone pair-π through the π-acidic surface of the PDI and a halogen bond via the σ-holes at the Cl/Br atoms). More in detail, thermal desorption (TD) experiments showed an increase in the VOC retention capacity upon increasing the length of the alkyl chain, suggesting a preference for the interaction with the PDI aromatic surface. In addition, the tetrachlorinated derivative showed larger VOC retention times compared to the tetrabrominated analog. These results were complemented by several state-of-the-art computational tools, such as the electrostatic surface potential analysis, the Quantum Theory of Atoms in Molecules (QTAIM), as well as the noncovalent interaction plot (NCIplot) visual index, which were helpful to rationalize the role of each interaction in the VOC···PDI recognition phenomena.

Insights on the Mechanical Properties of SARS-CoV-2 Particles and the Effects of the Photosensitizer Hypericin.

SARS-CoV-2 is a highly pathogenic virus responsible for the COVID-19 disease. It belongs to the Coronaviridae family, characterized by a phospholipid envelope, which is crucial for viral entry and replication in host cells. Hypericin, a lipophilic, naturally occurring photosensitizer, was reported to effectively inactivate enveloped viruses, including SARS-CoV-2, upon light irradiation. In addition to its photodynamic activity, Hyp was found to exert an antiviral action also in the dark. This study explores the mechanical properties of heat-inactivated SARS-CoV-2 viral particles using Atomic Force Microscopy (AFM). Results reveal a flexible structure under external stress, potentially contributing to the virus pathogenicity. Although the fixation protocol causes damage to some particles, correlation with fluorescence demonstrates colocalization of partially degraded virions with their genome. The impact of hypericin on the mechanical properties of the virus was assessed and found particularly relevant in dark conditions. These preliminary results suggest that hypericin can affect the mechanical properties of the viral envelope, an effect that warrants further investigation in the context of antiviral therapies.

[Determination of 13 chemical components of Epimedii Folium in pharmacopoeia by UPLC method combined with quantitative analysis of multicomponents by single-marker].

The quantitative analysis of multicomponents by single-marker(QAMS) was established for 13 chemical components of Epimedii Folium, including neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuoside Ⅰ, so as to investigate the feasibility and accuracy of this method in evaluating the quality of Epimedii Folium materials from different origins and different varieties. Through the scientific and accurate investigation of the experimental method, the external standard method was used to determine the content of 13 chemical components in epimedium brevieornu. At the same time, icariin was used as the internal standard, and the relative correction factors of icariin with neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuoside Ⅰ were established, respectively. The contens of neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuosideⅠ in Epimedii Folium were calculated by QAMS. Finally, the difference between the measured value and the calculated value was compared to verify the accuracy and scientific nature of QAMS in the determination. The relative correction factor of each component had better repeatability, and there was no significant difference between the results of the external standard method and those of QAMS. With icariin as the internal standard, QAMS simultaneously determining neoglycolic acid, chlorogenic acid, cryo-chlorogenic acid, magnolidine, hypericin, epimedin A, epimedin B, epimedin C, icariin, baohuoside Ⅱ, sagittatoside A, icariin subside Ⅰ, and baohuoside Ⅰ can be used for quantitative analysis of Epimedii Folium.