Small molecule deoxynyboquinone triggers alkylation and ubiquitination of Keap1 at Cys489 on Kelch domain for Nrf2 activation and inflammatory therapy.

Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) by Kelch-like ECH-associated protein 1 (Keap1) alkylation plays a central role in anti-inflammatory therapy. However, activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified. Deoxynyboquinone (DNQ) is a natural small molecule discovered from marine actinomycetes. The current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of Keap1. DNQ exhibited significant anti-inflammatory properties both in vitro and in vivo. The pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be the α, ß-unsaturated amides moieties by a chemical reaction between DNQ and N-acetylcysteine. DNQ exerted anti-inflammatory effects through activation of Nrf2/ARE pathway. Keap1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving alkylation. The specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass spectrometry. DNQ triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489 (Cys489) on Keap1-Kelch domain, ultimately enabling the activation of Nrf2. Our findings revealed that DNQ exhibited potent anti-inflammatory capacity through α, ß-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain, suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.

Cu(ii)/SPDO complex catalyzed asymmetric Baeyer-Villiger oxidation of 2-arylcyclobutanones and its application for the total synthesis of eupomatilones 5 and 6.

A novel classical kinetic resolution of 2-aryl-substituted or 2,3-disubstituted cyclobutanones of Baeyer-Villiger oxidation catalyzed by a Cu(ii)/SPDO complex is reported for the first time, producing normal lactones in excellent enantioselectivities (up to 96% ee) and regioselectivities (up to >20/1), along with unreacted ketones in excellent enantioselectivities (up to 99% ee). The current transformation features a wide substrate scope. Moreover, catalytic asymmetric total syntheses of natural eupomatilones 5 and 6 are achieved in nine steps from commercially available 3-methylcyclobutan-1-one.

The strategies of exercise intervention for adolescent depression: A meta-analysis of randomized controlled trials.

Purpose: This study aimed to investigate the effect of exercise intervention, and analyze exercise intervention strategies for adolescent depression through a meta-analysis of RCTs. Methods: Accordance to PRISMA guidelines, PubMed, Medline, EBSCO, Web of Science, SPORTDiscus, PsycINFO, ProQuest, and CNKI were searched for eligible records. Peer-reviewed studies were included if they met the following criteria: population (mean age of 10-18 years), intervention (physical activity, sport, or exercise), and outcomes (depression, adherence, ITT, dropout, adverse events, follow-up report). The protocol of this systematic review was registered in PROSPERO (CRD42022321683). Effect sizes calculations and methodological quality of exercise intervention (TESTEX scale) were carried out. The certainty of evidence was assessed by GRADE framework. Results: Thirteen randomized controlled trials were eligible for this review, which comprised a total of 433 adolescents. Compared with the control treatment, the effect of exercise on adolescent depression was moderate (SMD = -0.65, 95%CI: -1.03 to -0.27, p < 0.01). Heterogeneity was substantial (T 2 = 0.30, I 2 = 67%, p < 0.01). The moderating effect analysis showed that exercise intervention characteristics (organization form, exercise frequency, exercise intensity, exercise type, and single exercise session duration) of included studies varied greatly revealing multiple factors that may impact the antidepressant effect of exercise on adolescent depression (I 2 > 50%, p < 0.05). Three studies show that the positive effect of exercise on reducing depression in adolescents remained 40 weeks after the intervention. Moreover, owing to the included studies contained methodological limitations, the certainty of evidence was reduced to moderate level. Conclusion: This study shows that exercise intervention has a moderate and sustained positive effect on adolescent depression. Our results recommended that adolescents with depression undertake moderate to high intensity group mixed exercise for more than 12 weeks, 20 to 60 min/time, more than 3 times/week. Additionally, our study also shows that the antidepressant effects remained for a long time after the end of exercise interventions. However, following the GRADE framework, we rated the certainty of evidence the primary meta-analysis as moderate evidence due to some limitations of included studies. Therefore, rigorous studies are still needed to verify the results. Systematic review registration: [https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=321683], identifier [CRD42022321683].

Copper-Nitrene-Catalyzed Desymmetric Oxaziridination/1,2-Alkyl Rearrangement of 1,3-Diketones toward Bicyclic Lactams.

Although copper-nitrene has been extensively studied as a versatile active species in various transformations, asymmetric reactions involving copper-nitrene have been limited to the aziridination of olefins. Herein, we report the novel copper-nitrene-catalyzed desymmetric oxaziridination reaction of cyclic diketones with alkyl azides and the subsequent rearrangement of the resulting highly active intermediate, which produces a synthetically challenging chiral bicyclic lactam containing a quaternary carbon center. This procedure not only enriches the copper-nitrene-catalyzed asymmetric reactions, but also provides an alternative strategy to address the inherent challenges of catalytic asymmetric Schmidt reactions. This unique reaction could inspire the investigation of novel copper-nitrene-catalyzed asymmetric transformations and their reaction mechanisms.

Rapid determination and continuous monitoring of propofol in microliter whole blood sample during anesthesia by paper spray ionization-mass spectrometry.

Propofol is a widely used intravenous anesthetic agent in sedation and general anesthesia. To improve the safety and maintain the depth of anesthesia, it is important to develop a rapid, sensitive, and reliable method to monitor the concentration of propofol in blood during anesthesia continuously. Here, we present a novel strategy based on paper spray ionization-mass spectrometry (PSI-MS) to detect propofol. Samples (in 10 µL) were mixed with methanol as protein precipitation solvent and 2,6-dimethylphenol as internal standard. Protein micro-precipitation was achieved with methanol by vortexing and centrifuging for 5 s each, and propofol was extracted to the supernatant. PSI-MS was performed in negative ionization mode, and MS signal lasted for 1 min. The analysis of a single sample was completed within 2 min. The area ratios of propofol to internal standard were calculated for quantification. Limit of detection of 5.5 ng mL-1 and limit of quantification of 18.2 ng mL-1 were achieved for propofol in whole blood. Calibration curve was linear in the range of 0.02-10 µg mL-1. The developed method was used successfully in monitoring the propofol concentration in 3 patients' whole blood during anesthesia, showing its further application in controlling and feeding-back target concentration infusion. Graphical abstract.

Catalytic Asymmetric Total Syntheses of (-)-Galanthamine and (-)-Lycoramine.

The catalytic asymmetric total syntheses of the biologically important and therapeutically valuable Amaryllidaceae alkaloids (-)-galanthamine and (-)-lycoramine have been divergently achieved from commercially available 3-butyn-1-ol. A newly developed spirocyclic pyrrolidine (SPD)-catalyzed enantioselective Robinson annulation rapidly constructs the key cis-hydrodibenzofuran core, which bears an all-carbon quaternary stereocenter of the target molecules with an excellent stereoselective control. Additionally, the current asymmetric synthetic strategy provides an alternative approach toward the syntheses of (-)-galanthamine and its analogues.

Enantioselective synthesis of cis-hydrobenzofurans bearing all-carbon quaternary stereocenters and application to total synthesis of (‒)-morphine.

(‒)-Morphine, which is selected as an essential medicine by World Health Organization, is widely applied in the treatment of the pain-related diseases. Due to its synthetically challenging molecular architecture and important clinical role, extensive synthetic studies of morphine-type alkaloids have been conducted. However, catalytic asymmetric total synthesis of (‒)-morphine remains a long-standing challenge. Here, we disclose an efficient enantioselective total synthesis of (‒)-morphine in a longest linear sequence of 16 steps. The key transformation features a highly enantioselective Robinson annulation enabled by our spiro-pyrrolidine catalyst to rapidly construct the densely functionalized cis-hydrodibenzofuran framework containing vicinal stereocenters with an all-carbon quaternary center. This asymmetric approach provides an alternative strategy for the synthesis of (‒)-morphine and its analogues.

Pseudonocardia antitumoralis sp. nov., a deoxynyboquinone-producing actinomycete isolated from a deep-sea sediment.

An aerobic actinomycete, designated SCSIO 01299(T), was isolated from a deep-sea sediment collected from the northern South China Sea at a depth of 3258 m. The isolate was found to be a natural producer of the synthesized antitumour agent deoxynyboquinone and its three new derivatives, pseudonocardians A, B and C. A blast search based on almost-complete 16S rRNA gene sequences showed that strain SCSIO 01299(T) had high sequence similarities with members of the genus Pseudonocardia. The 16S rRNA gene sequence phylogenetic tree revealed that strain SCSIO 01299(T) was a member of the genus Pseudonocardia. Phenotypic analysis, chemotaxonomy and DNA-DNA relatedness could readily distinguish the isolate from established members in this genus. It was concluded that strain SCSIO 01299(T) represents a novel species, for which the name Pseudonocardia antitumoralis sp. nov. is proposed. The type strain is SCSIO 01299(T) ( = DSM 45322(T)  = CCTCC M 2011255(T)).

Streptomyces oceani sp. nov., a new obligate marine actinomycete isolated from a deep-sea sample of seep authigenic carbonate nodule in South China Sea.

A novel aerobic actinomycete strain, designated as SCSIO 02100(T), was isolated from a deep sea sediment sample collected from Northern South China Sea at a depth of 578 m. This isolate requires sea water or a sodium-supplemented medium for growth. BLAST searches based on the almost full length of the 16S rRNA gene sequence, showed that strain SCSIO 02100(T) had the highest similarities with Streptomyces armeniacus (JCM 3070(T)) (97.1 %). Phylogenetic trees reconstructed on the basis of 16S rRNA gene sequences revealed that strain SCSIO 02100(T) formed a distinct lineage with S. nanshensis SCSIO 01066(T) with 96.9 % similarity. Further analysis of the polyphasic taxonomic data, including morphological, phenotypic and chemotaxonomic properties, showed that strain SCSIO 02100(T) could be readily distinguished from the most closely related members of the genus Streptomyces. Thus, based on the polyphasic taxonomic data, a novel species, Streptomyces oceani sp. nov., is proposed, with the type strain SCSIO 02100(T) (=DSM 42043(T) = CGMCC 4.7007(T)).

[Characteristics of soil microelements contents in the rhizospheres of different vegetation in hilly-gully region of Loess Plateau].

To explore the rhizosphere effect of the microelements in the soils under different vegetation types in Loess Plateau, this paper analyzed the organic C, total N, Mn, Cu, Fe, and Zn contents in the rhizosphere soil and bulk soil of six vegetation types in hilly-gully region of Loess Plateau. Among the six vegetation types, Caragana korshinskii, Heteropappus altaicus, and Artemisia capillaries had higher organic C and total N contents in rhizosphere soil than in bulk soil. With the exception of C. korshinskii and H. rhamnoides, all the six vegetation types had a significantly lower pH in rhizosphere soil than in bulk soil. The six vegetation types had a lower available Mn content in rhizosphere soil than in bulk soil, and the C. korshinskii, Astragalus adsurgen, and Panicum virgatum had a significantly higher available Cu content in rhizosphere soil than in bulk soil. The six vegetation types except A. adsurgens had a slightly higher available Fe content in rhizosphere soil than in bulk soil, and A. adsurgens, P. virgatum, H. altaicus, and A. capillaries had a significant accumulation of available Zn in rhizosphere soil. There existed significant positive correlations between the rhizosphere soil and bulk soil of the six vegetation types in the relationships between the organic C and total N contents and the available Mn and Zn contents and between the contents of available Mn and Zn. In rhizosphere soil, available Mn and Zn contents were significantly negative- ly correlated with pH value. Due to the differences in root growth characteristics, rhizosphere pH value, and microbial structure composition, the microelements contents in the rhizosphere soil of the six vegetation types differed, with the contents of Mn, Cu, Fe, and Zn being higher in the rhizosphere soil of H. altaicus than in that of the other vegetation types.

Marininema mesophilum gen. nov., sp. nov., a thermoactinomycete isolated from deep sea sediment, and emended description of the family Thermoactinomycetaceae.

A novel filamentous bacterium, strain SCSIO 10219(T), was isolated from a sediment sample collected from the South China Sea (113° 3.752' E 18° 1.722' N) at a depth of 2105 m. Growth was observed at 25-35 °C (optimum 30 °C) and pH 5.0-8.0 (optimum pH 6.0-7.0). The organism formed yellow-white colonies with radial wrinkles. Aerial mycelium was not produced on any of the growth media tested. Phenotypic characterization and 16S rRNA gene sequence analysis indicated that strain SCSIO 10219(T) belongs to the family Thermoactinomycetaceae. The strain contained ll-diaminopimelic acid in the cell wall. The predominant menaquinone was MK-7. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine and five unknown phospholipids. Major fatty acids were anteiso-C(15:0) and iso-C(15:0). The DNA G+C content was 46.5 mol%. On the basis of chemotaxonomic properties and phylogenetic analysis based on 16S rRNA gene sequence data, it is proposed that this strain represents a novel species in a new genus, Marininema mesophilum gen. nov., sp. nov., in the family Thermoactinomycetaceae. The type strain of the type species is SCSIO 10219(T) ( = CCTCC AA 2011006(T) = DSM 45610(T)). In addition, we propose that the description of the family Thermoactinomycetaceae should be further emended based on the present study.

Streptomyces nanhaiensis sp. nov., a marine streptomycete isolated from a deep-sea sediment.

A novel aerobic streptomycete, strain SCSIO 01248T, was isolated from a sample of deep-sea sediment collected from the northern South China Sea, at a depth of 1632 m. This isolate formed yellow-white substrate mycelium and grey-white aerial hyphae. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SCSIO 01248T was most closely related to Streptomyces radiopugnans R97T (98.8 % sequence similarity), S. macrosporus NBRC 14748T (97.5 %) and S. megasporus NBRC 14749T (97.3 %). The novel strain could, however, be readily differentiated from S. radiopugnans DSM 41901T on the basis of some physiological and cellular chemical characteristics; the level of DNA-DNA relatedness between these two strains was only 40 %. Based on phylogenetic and phenotypic evidence, strain SCSIO 01248T represents a novel species, for which the name Streptomyces nanhaiensis sp. nov. is proposed. The type strain is SCSIO 01248T (=DSM 41926T=KCTC 19401T=CCTCC AA 208007T).

[Photosynthetic characteristics of Bothriochloa ischaemum under drought stress and elevated CO2 concentration].

A pot experiment was conducted to study the variations of the photo-physiological characteristics of native bluestem (Bothriochloa ischaemum) in loess hilly-gully region under different soil moisture condition (80% and 40% field capacity) and different atmospheric CO2 concentration (375 micromol x m(-2) x s(-1) and 750 micromol x m(-2) x s(-1). The results showed that drought stress decreased the maximum photosynthetic rate (Pn max), apparent quantum efficiency (AQE), stomatal conductance (ga), transpiration rate (Tx), maximum photochemical efficiency (F/Fm), potential photochemical efficiency (Fv/Fo), and photosynthetic pigments contents, and increased the malondialdehyde (MDA) and proline (Pro) contents. Under sufficient moisture condition, elevated CO2 concentration didn't change the P n max and the, MDA and Pro contents significantly; under drought stress, elevated CO2 improved the maximal fluorescence (Fm), Fv/Fm, Fv/Fo, photosynthetic pigments contents, and AQE, and the Pn max under elevated CO2 was increased significantly by 23.3%, and the MDA and Pro contents were decreased significantly, as compared with those under ambient CO2 concentration. All the results suggested that elevated CO2 concentration had definite compensation effect on the photosynthetic reduction of B. ischaemum induced by drought stress, and alleviated the damage of drought stress on B. ischaemum.

Chemical constituents of Dracocephalum forrestii.

A systematic phytochemical examination of the whole plant Dracocephalum forrestii led to the isolation of 4 new and 65 known chemical constituents. By detailed 1D and 2D NMR spectroscopic analyses, the new compounds were identified as 4-hydroxy-3-methoxyphenylethanol 8- O-[(6- O-syringoyl)- beta- D-glucopyranoside] (1), 3,4,5-trimethoxyphenylethanol beta- D-glucopyranoside ( 2), 4- O-[ beta- D-glucopyranosyl-(1 --> 3)- alpha- L-rhamnopyranosyl]phenylethylcinnamamide (3), and 9''- O- N-butyl lithospermate (4). The new isolates were evaluated for inhibitory activities against LPS-induced NO production in RAW 264.7 macrophages. Compound 2 revealed a moderate effect without any cytotoxicity under the assayed concentrations.

Proteomic analysis of 'hybrid necrosis' in wheat (Triticum aestivum) leaves.

Wheat hybrid necrosis has been genetically characterised for many years, but the specific gene(s) and the protein products involved in the processes remains unknown. In this study, protein expression in the base (B), mid (M) and tip (T) segments of the FL-2 leaves of a necrotic hybrid, PZF1 and its parents, Pan555 and Zheng891, was analysed and compared using a high throughput proteomic approach. Twenty-three protein spots, with significant variations in intensity across the necrotic leaf segments, were analysed by MALDI-TOF-MS, of which, 18 were matched to protein accessions in the NCBI database. Several of these proteins are enzymes involved in the methylation cycle, including AdoHcy hydrolase, AdoMet synthase 3 and methionine synthase 1; AdoHcy hydrolase was downregulated sharply in M and T, and AdoMet synthase 3 and methionine synthase 1 were upregulated gradually from M to T. This result suggests that methylation-associated processes, including epigenetic mechanisms, may play a role in the initiation and development of hybrid necrosis. Several energy cycle-associated proteins and cytoprotective proteins were also differentially expressed across the leaf segments, suggesting their direct association with or possible involvement in the necrotic processes. The significant imbalance of a heat-shock protein, a transposon protein and a RNA- and ssDNA-binding protein also makes these proteins potential molecular components in the necrotic processes.

The acarbose-biosynthetic enzyme AcbO from Actinoplanes sp. SE 50/110 is a 2-epi-5-epi-valiolone-7-phosphate 2-epimerase.

The C7-cyclitol 2-epi-5-epi-valiolone is the first precursor of the cyclitol moiety of the alpha-glucosidase inhibitor acarbose in Actinoplanes sp. SE50. The 2-epi-5-epi-valiolone becomes phosphorylated at C7 by the ATP dependent kinase AcbM prior to the next modifications. Preliminary data gave evidences that the AcbO protein could catalyse the first modification step of 2-epi-5-epi-valiolone-7-phosphate. Therefore, the AcbO protein, the encoding gene of which is also part of the acbKMLNOC operon, was overproduced and purified. Indeed the purified protein catalysed the 2-epimerisation of 2-epi-5-epi-valiolone-7-phosphate. The chemical structure of the purified reaction product was proven by nuclear magnetic resonance spectroscopy to be 5-epi-valiolone-7-phosphate.

Identification of a 1-epi-valienol 7-kinase activity in the producer of acarbose, Actinoplanes sp. SE50/110.

In the biosynthesis of the C7-cyclitol moiety, valienol, of the alpha-glucosidase inhibitor acarbose in Actinoplanes sp. SE50/110 various cyclitol phosphates, such as 1-epi-valienol-7-phosphate, are postulated precursors. In the cell extracts of Actinoplanes SE50/110 we found a new kinase activity which specifically phosphorylates 1-epi-valienol; other C7-cyclitol analogs were only weakly or not phosphorylated. The purified product of the kinase reaction turned out to be 1-epi-valienol-7-phosphate in analyses by nuclear magnetic resonance spectroscopy. The enzyme seems not to be encoded by an acb gene and, therefore, plays a role in a salvage pathway rather than directly in the de novo biosynthesis of acarbose.

Biosynthesis of the C(7)-cyclitol moiety of acarbose in Actinoplanes species SE50/110. 7-O-phosphorylation of the initial cyclitol precursor leads to proposal of a new biosynthetic pathway.

We have previously demonstrated that the biosynthesis of the C(7)-cyclitol, called valienol (or valienamine), of the alpha-glucosidase inhibitor acarbose starts from the cyclization of sedo-heptulose 7-phosphate to 2-epi-5-epi-valiolone (Stratmann, A., Mahmud, T., Lee, S., Distler, J., Floss, H. G., and Piepersberg, W. (1999) J. Biol. Chem. 274, 10889-10896). Synthesis of the intermediate 2-epi-5-epi-valiolone is catalyzed by the cyclase AcbC encoded in the biosynthetic (acb) gene cluster of Actinoplanes sp. SE50/110. The acbC gene lies in a possible transcription unit, acbKLMNOC, cluster encompassing putative biosynthetic genes for cyclitol conversion. All genes were heterologously expressed in strains of Streptomyces lividans 66 strains 1326, TK23, and TK64. The AcbK protein was identified as the acarbose 7-kinase, which had been described earlier (Drepper, A., and Pape, H. (1996) J. Antibiot. (Tokyo) 49, 664-668). The multistep conversion of 2-epi-5-epi-valiolone to the final cyclitol moiety was studied by testing enzymatic mechanisms such as dehydration, reduction, epimerization, and phosphorylation. Thus, a phosphotransferase activity was identified modifying 2-epi-5-epi-valiolone by ATP-dependent phosphorylation. This activity could be attributed to the AcbM protein by verifying this activity in S. lividans strain TK64/pCW4123M, expressing His-tagged AcbM. The His-tagged AcbM protein was purified and subsequently characterized as a 2-epi-5-epi-valiolone 7-kinase, presumably catalyzing the first enzyme reaction in the biosynthetic route, leading to an activated form of the intermediate 1-epi-valienol. The AcbK protein could not catalyze the same reaction nor convert any of the other C(7)-cyclitol monomers tested. The 2-epi-5-epi-valiolone 7-phosphate was further converted by the AcbO protein to another isomeric and phosphorylated intermediate, which was likely to be the 2-epimer 5-epi-valiolone 7-phosphate. The products of both enzyme reactions were characterized by mass spectrometric methods. The product of the AcbM-catalyzed reaction, 2-epi-5-epi-valiolone 7-phosphate, was purified on a preparative scale and identified by NMR spectroscopy. A biosynthetic pathway for the pseudodisaccharidic acarviosyl moiety of acarbose is proposed on the basis of these data.

[Study on the EMF-temperature co-effects on protein conformation by fluorometry].

The bioelectromagnetic effects are wildly concerned for a long time, and related researches are conducted in all kinds of directions in recent years. The EMF-temperature co-effects are more interesting nowadays. By studying the effects of EMF co-operated with temperature on a protein, an irreversible protein denaturation is found under the processing of EMF, and this denaturation is also Arrhenius-rule-obeyed. In addition, a protein denaturation model under the EMF-temperature co-effects is built. In this paper the EMF-temperature co-effects are explained in a way of molecular reacting kinetics, and the athermal effects of EMF are also discussed to some degree.