Walnut glutelin is a storage protein of high nutritional value, but its composition, structure, and applications in foods have not been fully studied. In this work, walnut glutelin was obtained using the Osborne fractionation method and identified by liquid chromatography-tandem mass spectrometry. The main components of the extracted walnut glutelin were legumin B-like, 11S globulin-like, 11S globulin seed storage protein Jug r 4, and 11S globulin seed storage protein 2-like. Besides, the adsorption behaviors of walnut glutelin and its linear as well as nonlinear rheological properties at the air–water interface were investigated. Results showed that at a low concentration of 10 μg/mL (

New ambuic acid derivatives, pestallic acids R–V (1−5), together with ambuic acid (6), were isolated from the endophytic fungus Pestalotiopsis trachicarpicola SC-J551 derived from the fern Blechnum orientale L., of which compound 2, being racemic, was separated to two optically pure enantiomers (+)-2 and (−)-2. The structures including absolute configurations of these new compounds were elucidated by extensive spectroscopic analysis and theoretical simulations of their ECD spectra and 13C NMR chemical shifts. Compounds 1 and 3 exhibited cytotoxicity against human carcinoma A549, HeLa, HepG2, and MCF-7 cells (IC50: 3.6–12.5 μM) and compound 3 was also active against Staphylococcus aureus and MRSA (MIC = 20 μg ml−1). Compound (±)-2 showed inhibitory activity against LPS-induced NO release (IC50 = 21.1 μM) and t-BHP-induced ROS production (IC50 = 8.5 μM) in RAW264.7 macrophages.

Three previously undescribed isopimarane-type diterpene glycosides named as xylarcurcosides A-C (1–3) along with two known ones 16-α-d-mannopyranosyloxyisopimar-7-en-19-oic acid (4) and hypoxylonoid A (5) were successfully isolated from an ethyl acetate extract of the endophytic fungus Xylaria curta YSJ-5 growing in leaves of Alpinia zerumbet. The spectroscopic methods, electronic circular dichroism (ECD) calculations, and X-ray diffraction experiments were conducted to identify their absolute chemical structures. All these compounds were tested for in vitro cytotoxic, anti-inflammatory, α-glucosidase inhibitory, and antibacterial activities. As a result, these novel compounds demonstrated no obvious cytotoxic and antibacterial activity.

Squamocin, an annonaceous acetogenin isolated from plants in the Annonaceae family, has antitumour activity. In this study, we report that Sq-2, a biotinylated squamocin monomer, has a favorable antitumour effect on MDA-MB-231 and SKBR3 breast cancer cells in vitro. MTT assays show that Sq-2 has a better antitumour effect on MDA-MB-231 cells than Sq-5 and Sq-6. Furthermore, RNA-Seq and KEGG enrichment analyses reveal that Sq-2 activates the MAPK signaling pathway, and results of western blot analysis demonstrate that Sq-2 activates the JNK and p38 pathways in MDA-MB-231 and SKBR3 cells. Flow cytometry and western blot analysis reveal that Sq-2 induces cell apoptosis by increasing the expressions of cleaved Caspase-3 and cleaved PARP as well as the ratio of Bax/Bcl-2. Inhibition of the Caspase family by Z-VAD-FMK attenuates the viability of MDA-MB-231 cells, indicating that Sq-2 induces apoptosis in a Caspase-dependent manner. Additionally, pretreatment with the p38 inhibitor SB203580 or JNK inhibitor SP600125 partially reverses the increase in the apoptosis rate and decrease in cell viability prompted by Sq-2. Furthermore, Sq-2 treatment decreases the expression level of CyclinD1 and increases the expression levels of p21, p27, CyclinA1, and CDK2, causing S-phase arrest in MDA-MB-231 and SKBR3 cells. Further study indicates that Sq-2 stimulates autophagy in MDA-MB-231 and SKBR3 cells, and inhibition of autophagy by bafilomycin A1 increases cell viability and promotes cell survival. Sq-2, a novel biotin-squamocin compound, shows a significant inhibitory effect on the propagation of SKBR3 and MDA-MB-231 breast cancer cells. Furthermore, Sq-2 treatment not only induces S-phase arrest and activates the JNK and p38 pathways to trigger apoptosis but also causes autophagy to promote apoptosis in MDA-MB-231 and SKBR3 cells. .

Eleven new phenyltetracenoid polyketides, streptovertimycins U (1) and V (2), 14-bromo-streptovertidione (3), streptovertimycins W-Y (4-6), and streptovertimycins Z1-Z5 (7-11), together with the known congeners fasamycins R (12) and S (13) and accramycins A (14) and B (15), were isolated from the NaBr-supplemented rice-grown cultures of Streptomyces morookaense SC1169. Their structures were elucidated by extensive spectroscopic analysis, single-crystal X-ray diffraction analysis, and theoretical computations of ECD spectra. Compounds 1 and 2 are methylene-bridged dimers of accramycin A, and compounds 3 and 7-11 are brominated fasamycin congeners. Compounds 5 and 8-14 exhibited activity against the drug-resistant bacteria MRSA and VRE (MIC = 0.6-5.0 μg/mL), and the dimer 1 displayed activity against MRSA (MIC = 2.5 μg/mL). Compounds 6-15 showed cytotoxicity against the human carcinoma A549, HeLa, HepG2, and MCF-7 cells in the IC50 range between 1.7 and 9.2 μM.

Five previously undescribed specialized metabolites, including three 9,11-seco-pimarane diterpenoids, nodulisporenones A-C, and two androstane steroids, nodulisporisterones A and B, together with previously described ergosterol derivatives, dankasterone A and demethylincisterol A3, were isolated from solid cultures of the endophytic fungus Nodulisporium sp. SC-J597. Their structures including absolute configurations were elucidated by extensive spectroscopic analysis and theoretical calculations of electronic circular dichroism spectra. Among them, nodulisporenones A and B are the first examples of seco-pimarane diterpenoids that is cyclized to form an unprecedented diterpenoid lactone scaffold and nodulisporisterones A and B represent the first normal C19 androstane steroids of fungal origin. Nodulisporisterone B exhibited potent inhibitory effect on the production of NO in LPS-stimulated RAW264.7 macrophages (IC50 = 2.95 mu M). This compound, together with the two known ergosterol derivatives, also displayed cytotoxicity against A549, HeLa, HepG2 and MCF-7 cancer cell lines with IC50 values of 5.2-16.9 mu M.

Lysine benzoylation (Kbz) is a recently discovered post-translational modification associated with active transcription. However, the proteins for maintaining and interpreting Kbz and the physiological roles of Kbz remain elusive. Here, we systematically characterize writer, eraser, and reader proteins of histone Kbz in S. cerevisiae using proteomic, biochemical, and structural approaches. Our study identifies 27 Kbz sites on yeast histones that can be regulated by cellular metabolic states. The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex and NAD + -dependent histone deacetylase Hst2 could function as the writer and eraser of histone Kbz, respectively. Crystal structures of Hst2 complexes reveal the molecular basis for Kbz recognition and catalysis by Hst2. In addition, we demonstrate that a subset of YEATS domains and bromodomains serve as Kbz readers, and structural analyses reveal how YEATS and bromodomains recognize Kbz marks. Moreover, the proteome-wide screening of Kbz-modified proteins identifies 207 Kbz sites on 149 non-histone proteins enriched in ribosome biogenesis, glycolysis/gluconeogenesis, and rRNA processing pathways. Our studies identify regulatory elements for the Kbz pathway and provide a framework for dissecting the biological functions of lysine benzoylation.

Linalool, which is one of the most representative aroma substances in tea, is transformed into other aroma related compounds, including linalool 3,6-oxides and linalool 3,7-oxides. The objective of this study was to elucidate the linalool oxide synthesis pathway and its response to stress in tea. By feeding experiment, chemical synthesis, and compound analysis, it was found that linalool can be transformed to linalool oxides via 6,7-epoxylinalool. The conversion rate from 6,7-epoxylinalool to linalool oxides was relatively high under acidic conditions. Four linalool oxide glucosides obtained from tea were structurally characterized. Additionally, tea green leafhopper infestation was observed to activate the whole metabolic flow from linalool into linalool oxides and their glucosides (p < 0.01). Moreover, light treatments further increased the accumulation of linalool oxides and their glucosides (p < 0.05). These results will be useful for elucidating the mechanism mediating linalool oxides content changes in response to stress in tea.

Annonaceous acetogenins are potent ubiquinone-linked NADH oxidase inhibitors and have potent anticancer activity. Their usage in the clinic is limited because of their significant toxicity to normal cells. To obtain novel low toxicity antitumoral prodrugs, squamocin and bullatacin were covalently linked to N-butoxycarbonyl protected glycine-proline dipeptide (Boc-Gly-Pro), which may be recognized and cleaved by fibroblast activation protein (FAP), a serine protease overexpressed on the surface of tumor-associated fibroblasts. Ten squamocin and bullatacin derivatives were synthesized by attaching Boc-Gly-Pro either directly or through 6-aminocaproic acid linker to a hydroxyl group of squamocin or bullatacin. All derivatives showed high potency to inhibit 4T1 breast cancer cell line growth in the sub-µM to µM range. Compound 8 was the most active (IC50 0.30 μM) and displayed higher activity than squamocin. Most derivatives, however, display reduced potency by up to 50 folds compared to the parent drug. In the presence of FAP enzyme, the anticancer potency of compound 3 against A549, HeLa, HepG2 and MCF-7 cells was increased by up to eight folds. The data suggest that Boc-Gly-Pro-acetogenin prodrugs may show improved therapeutic potential of these acetogenins by reducing the drug doses and the toxic side effects.

Three new lipopeptaibols, halovirs I–K (1–3), were isolated from the solid culture of the phytopathogenic fungus Paramyrothecium roridum NRRL 2183. Their planar structures, which consist of a hexapeptide backbone and acyl substitutions at the N- and C-termini, were elucidated by comprehensive analysis of the 1D and 2D NMR spectroscopic data along with the detailed interpretation of the MS/MS fragmentation pattern. Absolute configurations of the amino acid/1,2-amino alcohol residues were determined using the advanced Marfey’s method. Bioinformatics analysis of the genome assembly of P. roridum NRRL 2183 revealed a gene cluster that is likely responsible for the biosynthesis of halovirs I–K. Analysis of the module and domain organization of the putative halovir synthetase PrHalA indicated that the assembly of 1–3 proceeds in an unconventional nonlinear fashion. 1 and 2 exhibited potent antibacterial activity against both antibiotic-sensitive and multidrug-resistant Gram-positive pathogens. These lipopeptaibols also displayed significant cytotoxicity toward human lung carcinoma A549, human breast carcinoma MCF-7, and human cervical carcinoma HeLa cells with IC50 values ranging from 1.3 to 3.3 μM.

Six previously undescribed cytochalasans, ueckerchalasins A−E and 4′-hydroxycytochalasin J3, together with eight known congeners, were isolated from solid cultures of the endophytic fungus Diaporthe ueckerae SC-J0123 which was originally isolated from the leaves of Pteris vittata L. Their structures were elucidated by extensive spectroscopic analysis, single-crystal X-ray diffraction, and theoretical simulations of ECD spectra and 13C NMR shifts. Ueckerchalasins A–C have a carbon-carbon bridge between C-14 and C-20, forming a rare 5/6/6/7-fused heterocyclic core. Ueckerchalasins C and D displayed selective activity against human carcinoma HeLa and HepG2 cells. Ueckerchalasins C was also active against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA).

Background: Butaselen is an ebselen analog that is under clinical trials for treating hepatic and pulmonary fibrosis. Our previous studies showed that butaselen is mainly present in human plasma in the form of M2, a free Se-methylated metabolite. Objective: This study aimed to investigate the metabolic mechanisms of butaselen. Methods and Results: Butaselen was incubated with human plasma. Butaselen immediately disappeared, and the butaselen-HSA (human serum albumin) adduct was detected by HPLC-HRMS, showing that butaselen covalently binds to HSA. The butaselen-HSA adduct was precipitated using acetonitrile and then incubated with PBS, Cys, and GSH for 1 hour. The product was M1, a reduced form of butaselen. The results indicated that HSA, Cys, and GSH can reduce the butaselen-HSA covalent bond. The binding site for butaselen could be the cysteine-34 residue of HSA through pronase and trypsin hydrolysis. Incubating butaselen with cysteine, butaselen-Cys, butaselen-2Cys, and M1 were generated, indicating the covalent binding and reduction of butaselen by cysteine. We incubated liver microsomes and cytosol with butaselen, 6.22 and 246 nM M2 were generated, respectively. The results demonstrated that cytosolic enzymes are mainly involved in M2 production. The amount of M2 in the liver cytosol decreased from 246 nM to 2.21 nM when 10 mM m-anisic acid (a specific TPMT enzyme inhibitor) was added, showing that TPMT is responsible for M2 formation. Conclusion: Butaselen was covalently bound to HSA, and the binding site was the cysteine-34 residue of HSA. The butaselen-HSA adduct was reduced by free thiol compounds to generate M1. M1 was further metabolized to M2 by cytosolic TPMT. This study provides a basis for studying the pharmacokinetics of selenium-containing drugs.

Human mixed-lineage leukemia (MLL) family methyltransferases methylate histone H3 lysine 4 to different methylation states (me1/me2/me3) with distinct functional outputs, but the mechanism underlying the different product specificities of MLL proteins remains unclear. Here, we develop methodologies to quantitatively measure the methylation rate difference between mono-, di-, and tri-methylation steps and demonstrate that MLL proteins possess distinct product specificities in the context of the minimum MLL-RBBP5-ASH2L complex. Comparative structural analyses of MLL complexes by X-ray crystal structures, fluorine-19 nuclear magnetic resonance, and molecular dynamics simulations reveal that the dynamics of two conserved tyrosine residues at the "F/Y (phenylalanine/tyrosine) switch"positions fine-tune the product specificity. The variation in the intramolecular interaction between SET-N and SET-C affects the F/Y switch dynamics, thus determining the product specificities of MLL proteins. These results indicate a modified F/Y switch rule applicable for most SET domain methyltransferases and implicate the functional divergence of MLL proteins.

We extracted one new C-methyl flavonoid, farrerol 7-O-β-d-(6-O-galloyl)glucopyranoside (1), along with 11 known flavonoids, from the Cleistocalyx (C.) conspersipunctatus leaves. Elucidation of these flavonoid structures was accomplished through spectroscopic investigation and electronic circular dichroism (ECD) computation. Compared to corosolic acid (IC50: 15.5 ± 0.9 μM), an established inhibitor, the compound 1 (IC50: 6.9 ± 1.2 μM) was found more active in suppressing α-glucosidase. These findings imply the potential of compound 1 as a valid α-glucosidase inhibitor, which also offer evidence for future animal experiments and clinical trials. Besides, molecular docking was employed to explore the probable mechanism for α-glucosidase–compound 1 interaction. The biosynthetic pathway of these flavonoids in C. conspersipunctatus were proposed.

Four new pestalone-type benzophenones, pestalotinones A–D ( 1 − 4 ), along with six known congeners, pestalone, pestalone E–F, SB87-Cl, SB87-H, and pestalachloride B, were isolated from the endophytic fungus Pestalotiopsis trachicarpicola SC-J551 cultivated on rice grains. Their structures were established by extensive spectroscopic analysis. Compounds 1 − 3 exhibited potent activity against Staphylococcus aureus and MRSA (MIC: 1.25–2.5 μg ml −1 ) while no cytotoxicity against Vero cells (IC 50 > 50 μM). The activity profile of this group of compounds suggested that replacement of the C-14 aldehyde with an oxymethyl greatly increases their activity and selectivity towards the bacteria and chlorine substitutions result in the increase of antibacterial activity and slight decrease of cytotoxicity against the mammalian cells.

Air pollution adversely affects skin, leading to skin inflammation and premature skin aging. Plant derived antioxidant compounds have been considered to be promising in discovery of effective agents for the protection of skin from the damage by air pollutants. Our previous studies demonstrated that Averrhoa carambola fruit (known as star fruit) is rich in flavonoid C -glycosides with unique structures and potent antioxidant activity. Thus, the star fruit extract (SFE) and main flavonoid C -glycoside components, carambolasides I, J, and P ( 1 – 3 ), carambolaflavone B ( 4 ), and isovitexin 2″- O -α- l -rhamnoside ( 5 ), were investigated for the activity against air pollutant stress in human epidermis. As a result, SFE and compounds 1 – 5 exhibited significant inhibitory activity against protein carbonylation in oxidative-stressed stratum corneum with the best activity being shown by compound 3 . SFE and compounds 2 – 5 were also active against engine exhaust-induced protein carbonylation in stratum corneum. When further evaluated, SFE and compound 3 significantly inhibited gene expression of the key inflammation mediators IL-1α and COX-2 in PM-stressed keratinocytes. The results indicated that SFE and the flavonoid C -glycosides are potentially effective against air pollutant-induced skin inflammation and premature aging. Graphical Abstract

The ULK complex initiates the autophagosome formation, and has recently been implicated in selective autophagy by interacting with autophagy receptors through its FIP200 subunit. However, the structural mechanism underlying the interactions of autophagy receptors with FIP200 and the relevant regulatory mechanism remain elusive. Here, we discover that the interactions of FIP200 Claw domain with autophagy receptors CCPG1 and Optineurin can be regulated by the phosphorylation in their respective FIP200-binding regions. We determine the crystal structures of FIP200 Claw in complex with the phosphorylated CCPG1 and Optineurin, and elucidate the detailed molecular mechanism governing the interactions of FIP200 Claw with CCPG1 and Optineurin as well as their potential regulations by kinase-mediated phosphorylation. In addition, we define the consensus FIP200 Claw-binding motif, and find other autophagy receptors that contain this motif within their conventional LC3-interacting regions. In all, our findings uncover a general and phosphoregulatable binding mode shared by many autophagy receptors to interact with FIP200 Claw for autophagosome biogenesis, and are valuable for further understanding the molecular mechanism of selective autophagy.

Schistosomiasis poses a serious threat to human health and remains a major tropical and parasitic disease in more than 70 countries. Praziquantel (PZQ) has been the primary treatment for schistosomiasis for nearly 4 decades. ABSTRACT Schistosomiasis poses a serious threat to human health and remains a major tropical and parasitic disease in more than 70 countries. Praziquantel (PZQ) has been the primary treatment for schistosomiasis for nearly 4 decades. However, its efficacy against migratory-stage schistosomula is limited. Radicicol (RAD), a β-resorcylic acid lactone derived from Paecilomyces sp. strain SC0924, was investigated as an alternative treatment for Schistosoma japonicum. In vitro tests showed that within 72 h, RAD (10 μmol/liter) completely killed schistosomula of both skin and liver stages with an efficacy significantly higher than that of PZQ, although it was less potent against adult worms than PZQ. In vivo, RAD reduced worm burdens and liver eggs by 91.18% and 86.01%, respectively, by killing migratory-stage schistosomula. Optical microscopy and scanning electron microscopy revealed that RAD damaged the epiderm and tegument morphology of S. japonicum worms at various stages and altered their motility to different degrees. RAD exhibited schistosomicidal effects at different stages in vitro and in vivo, especially at the migratory stage, implying that its mechanism could be different from that of PZQ. Collectively, these results showed that RAD is promising as a lead for the development of drugs to control the migratory-stage schistosomula of S. japonicum.

The recruitment of Unc-51-like kinase and TANK-binding kinase 1 complexes is essential for Nuclear dot protein 52-mediated selective autophagy and relies on the specific association of NDP52, RB1-inducible coiled-coil protein 1, and Nak-associated protein 1 (5-azacytidine-induced protein 2, AZI2). However, the underlying molecular mechanism remains elusive. Here, we find that except for the NDP52 SKIP carboxyl homology (SKICH)/RB1CC1 coiled-coil interaction, the LC3-interacting region of NDP52 can directly interact with the RB1CC1 Claw domain, as that of NAP1 FIP200-binding region (FIR). The determined crystal structures of NDP52 SKICH/RB1CC1 complex, NAP1 FIR/RB1CC1 complex, and the related NAP1 FIR/Gamma-aminobutyric acid receptor-associated protein complex not only elucidate the molecular bases underpinning the interactions of RB1CC1 with NDP52 and NAP1 but also reveal that RB1CC1 Claw and Autophagy-related protein 8 family proteins are competitive in binding to NAP1 and NDP52. Overall, our findings provide mechanistic insights into the interactions of NDP52, NAP1 with RB1CC1 and ATG8 family proteins.

Five new pentacyclic triterpenoids, 6a-hydroxyursolic acid (1), 6 alpha-hydroxycorosolic acid (2), 6-oxo-maslinic acid (3), 6-oxo-delta-maslinic acid (4), and 6-oxo-alphitolic acid (5), along with 15 known analogues were isolated from the leaves of Cleistocalyx conspersipunctatus. Their structures were elucidated by spectroscopic analysis. Compound 1 displayed better alpha-glucosidase inhibitory activity (IC50: 2.6 mu M) than the known inhibitor corosolic acid (IC50: 15.5 mu M). Structure-activity relationships in the activity were discussed for this group of isolates.