Chromomycins from soil-derived Streptomyces sp. inhibit the growth of human non-small cell lung cancer cells by targeting c-FLIP.

Three chromomycin derivatives, chromomycins A3 (1, CA3), A5 (2, CA5), and monodeacetylchromomycin A3 (3, MDA-CA3), were identified from the soil-derived Streptomyces sp. CGMCC 26516. A reinvestigation of the structure of CA5 is reported, of which the absolute configuration was unambiguously determined for the first time to be identical with that of CA3 based on nuclear magnetic resonance (NMR) data analysis as well as NMR and electronic circular dichroism calculations. Compounds 1-3 showed potent cytotoxicity against the non-small-cell lung cancer (NSCLC) cells (A549, H460, H157-c-FLIP, and H157-LacZ) and down-regulated the protein expression of c-FLIP in A549 cells. The IC50 values of chromomycins in H157-c-FLIP were higher than that in H157-LacZ. Furthermore, si-c-FLIP promoted anti-proliferation effect of chromomycins in NSCLC cells. In nude mice xenograft model, 1 and 2 both showed more potent inhibition on the growth of H157-lacZ xenografts than that of H157-c-FLIP xenografts. These results verify that c-FLIP mediates the anticancer effects of chromomycins in NSCLC.

The crosstalk between metabolic reprogramming and epithelial-mesenchymal transition and their synergistic roles in distant metastasis in breast cancer.

BACKGROUND: Metabolic reprogramming (MR) and epithelial-mesenchymal transition (EMT) are crucial phenomena involved in the distant metastasis of breast cancer (BRCA). This study aims to assess the risk of distant metastasis in BRCA patients based on MR and EMT processes and investigate their underlying mechanisms. METHODS: Gene sets related to EMT and MR were downloaded. MR-related genes (MRG) and EMT-related genes (ERG) were obtained. Principal Component Analysis method was used to define the EMT Potential Index (EPI) and MR Potential Index (MPI) to quantify the EMT and MR levels in each tumor tissue. A linear scoring model, the Metastasis Score, was derived using the union of MRGs and ERGs to evaluate the risk of distant metastasis/recurrence in BRCA. The Metastasis Score was then validated in multiple datasets. Additionally, our study explored the underlying mechanism of the Metastasis Score and its association with tumor immunity, focusing on HPRT1 gene expression in breast cancer tissues of transfer and untransferred groups using experimental methods. RESULTS: A total of 59 MRGs and 30 ERGs were identified in the present study. Stratifying the dataset based on EPI and MPI revealed significantly lower survival rates (P < .05) in the MPI_high and EPI_high groups. Kaplan-Meier analysis indicated the lowest survival rate in the EPI-high + MPI-high group. The Metastasis Score demonstrated its ability to distinguish prognoses in GSE2034, GSE17705, and TCGA-BRCA datasets. Additionally, differences in mutated genes were found between the high- and the low-Metastasis Score groups, displaying significant associations with immune cell infiltration and anti-tumor immune status. Notably, the 13 genes included in the Metastasis Score showed a strong association with prognosis and tumor immunity. Immunohistochemistry and western blot results revealed high expression of the HPRT1 gene in the transfer group. CONCLUSION: This study established the Metastasis Score as a reliable tool for evaluating the risk of distant metastasis/recurrence in BRCA patients. Additionally, we identified key genes involved in MR and EMT crosstalk, offering valuable insights into their roles in tumor immunity and other relevant aspects.

METTL3-modified lncRNA DSCAM-AS1 promotes breast cancer progression through inhibiting ferroptosis.

Numerous studies have indicated that N6-methyladenosine (m6A) and lncRNAs play pivotal roles in human cancer. However, the underlying functions and mechanisms of m6A-lncRNA in the physiological processes of breast cancer remain unclear. Here, we found that DSCAM-AS1 is an m6A-modified lncRNA that was overexpressed in breast cancer tissues and cells, indicating poor clinical prognosis. Gain/loss functional assays suggested that DSCAM-AS1 inhibited erastin-induced ferroptosis in breast cancer cells. Mechanistically, there were remarkable m6A modification sites on both the 3'-UTR of DSCAM-AS1 and the endogenous antioxidant factor SLC7A11. M6A methyltransferase methyltransferase-like 3 (METTL3) methylated both SLC7A11 and DSCAM-AS1. Moreover, DSCAM-AS1 recognized m6A sites on the SLC7A11 mRNA, thereby enhancing its stability. Taken together, these findings indicated a potential therapeutic strategy for breast cancer ferroptosis in an m6A-dependent manner.

Mrakia polaris sp. nov. and Mrakia amundsenii sp. nov. (Mrakiaceae, Cystofilobasidiales), two novel psychrophilic yeast species isolated from Arctic habitats.

Four yeast strains belonging to the basidiomycetous yeast genus Mrakia were isolated from diverse habitats in the Ny-Ålesund region (Svalbard, High Arctic): two from vascular plants, one from seawater and one from freshwater. Phylogenetic analysis, based on the ITS region and the D1/D2 domain of the 28S rRNA gene, identified these four strains as representing two novel species within the genus Mrakia. The names Mrakia polaris sp. nov. (MycoBank number: MB 852063) and Mrakia amundsenii sp. nov. (MycoBank number: MB 852064) are proposed. These two new species show distinct psychrophilic adaptations, as they exhibit optimal growth at temperatures between 10 and 15°C, while being unable to grow at 25°C. The holotype of M. polaris sp. nov. is CPCC 300345T, and the holotype of M. amundsenii sp. nov. is CPCC 300572T.

Application of a modified lateral thoracic artery perforator flap in partial breast defects.

Background: Breast cancer has become the most frequently diagnosed cancer in the world. Detection at an early stage, frequently allows women to benefit from breast conserving surgery. However, some patients are not satisfied with the breast shape after breast-conserving surgery, and autologous tissue flaps are needed to fill the defect in the resection area. The modified lateral thoracic artery perforator (LTAP) flap isn't one of the commonly used flaps in breast surgery and has the advantages of a reliable blood supply, simple operation and few postoperative complications. In this study, we aimed to evaluate the feasibility and effectiveness of a modified LTAP flap for repairing partial breast defects after breast-conserving surgery. Methods: In this study, we retrospectively analyzed the clinical data of 126 patients treated with LTAP flaps to repair local breast defects at Affiliated Hospital of Guangdong Medical University between January 2020 and June 2021. Data were collected on the demographic characteristics of these patients, tumor size and location, type of axillary lymph node surgery, availability of adjuvant chemotherapy and radiotherapy, and postoperative complications. Results: The median weight of the tumor specimen was 185 g (range, 170-320 g), and this glandular tissue accounted for 30% to 40% of the total breast volume. The average flap size was 10.5 cm ×2.5 cm (length range, 8-15 cm, width range: 2-4 cm). The minimum follow-up time was 6 months, with an average of 10 months (range, 6-22 months). The mean operative time was 130 minutes (range: 90-180 minutes), and the mean hospital stay was 3 days (range, 2-5 days). All modified LTAP flaps survived completely without donor site complications. None of the patients required revision surgery on the postoperative breast. Conclusions: The modified LTAP flap is a reliable method for repairing partial breast defects after breast-conserving surgery. It has the advantages of a simple operation, a reliable blood supply, fewer postoperative complications, and a high flap survival rate. It is especially suitable for Asian women with small breast volumes and can achieve good breast contouring effects.

Unexpected Noremestrin with a Sulfur-Bearing 15-Membered Macrocyclic Lactone from Emericella sp. 1454.

Two previous unreported epipolythiodioxopiperazines of the emestrin family, namely, noremestrin A (1) and secoemestrin E (2), were successfully isolated from the fungal source Emericella sp. 1454. Employing comprehensive spectroscopic techniques, such as high-resolution electrospray ionization mass spectrometry, infrared, and nuclear magnetic resonance (NMR), along with NMR and electronic circular dichroism calculations, the chemical structures of compounds 1 and 2 were elucidated. Particularly noteworthy is the distinctive nature of noremestrin A, representing the inaugural instance of a noremestrin variant incorporating a sulfur-bearing 15-membered macrocyclic lactone moiety. Compounds 1 and 2 exhibited weak cytotoxic activities against the human chronic myelocytic leukemia cell lines MEG-01 and K562.

Eleuthemarins A and B, two new isocoumarin derivatives from the Arctic fungus Eleutheromyces sp. CPCC 401592.

Two new isocoumarin derivatives, eleuthemarins A (1) and B (2), were isolated from the Arctic fungus Eleutheromyces sp. CPCC 401592. Their structures and absolute configurations were elucidated through spectroscopic methods, quantum chemical calculations of NMR shifts, and calculated electronic circular dichroism. This is the first report for the chemical investigation of the genus Eleutheromyces. Compounds 1 and 2 showed selective cytotoxic activities against H460, A549, and HCT116 cancer cell lines with IC50 values in the range of 24.1-57.3 µM, respectively. Compound 1 displayed weak antibacterial activities.

Three new isocoumarin analogues from an endolichenic fungus Aspergillus flavus CPCC 400810.

Five isocoumarin derivatives including three new compounds, aspermarolides A-C (1-3), and two known analogues, 8-methoxyldiaporthin (4) and diaporthin (5) were obtained from the culture extract of Aspergillus flavus CPCC 400810. The structures of these compounds were elucidated by spectroscopic methods. The double bond geometry of 1 and 2 were assigned by the coupling constants. The absolute configuration of 3 was determined by electronic circular dichroism experiment. All compounds showed no cytotoxic activities against the two human cancer cells HepG2 and Hela.

The role of peroxisome proliferator-activated receptors in the tumor microenvironment, tumor cell metabolism, and anticancer therapy.

Peroxisome proliferator-activated receptors (PPARs) have been extensively studied for over 3 decades and consist of three isotypes, including PPARα, γ, and ß/δ, that were originally considered key metabolic regulators controlling energy homeostasis in the body. Cancer has become a leading cause of human mortality worldwide, and the role of peroxisome proliferator-activated receptors in cancer is increasingly being investigated, especially the deep molecular mechanisms and effective cancer therapies. Peroxisome proliferator-activated receptors are an important class of lipid sensors and are involved in the regulation of multiple metabolic pathways and cell fate. They can regulate cancer progression in different tissues by activating endogenous or synthetic compounds. This review emphasizes the significance and knowledge of peroxisome proliferator-activated receptors in the tumor microenvironment, tumor cell metabolism, and anti-cancer treatment by summarizing recent research on peroxisome proliferator-activated receptors. In general, peroxisome proliferator-activated receptors either promote or suppress cancer in different types of tumor microenvironments. The emergence of this difference depends on various factors, including peroxisome proliferator-activated receptor type, cancer type, and tumor stage. Simultaneously, the effect of anti-cancer therapy based on drug-targeted PPARs differs or even opposes among the three peroxisome proliferator-activated receptor homotypes and different cancer types. Therefore, the current status and challenges of the use of peroxisome proliferator-activated receptors agonists and antagonists in cancer treatment are further explored in this review.

Genomic and Transcriptomic Approaches Provide a Predictive Framework for Sesquiterpenes Biosynthesis in Desarmillaria tabescens CPCC 401429.

Terpenoids constitute a structurally diverse class of secondary metabolites with wide applications in the pharmaceutical, fragrance and flavor industries. Desarmillaria tabescens CPCC 401429 is a basidiomycetous mushroom that could produce anti-tumor melleolides. To date, no studies have been conducted to thoroughly investigate the sesquiterpenes biosynthetic potential in Desarmillaria or related genus. This study aims to unravel the phylogeny, terpenome, and functional characterization of unique sesquiterpene biosynthetic genes of the strain CPCC 401429. Herein, we report the genome of the fungus containing 15,145 protein-encoding genes. MLST-based phylogeny and comparative genomic analyses shed light on the precise reclassification of D. tabescens suggesting that it belongs to the genus Desarmillaria. Gene ontology enrichment and pathway analyses uncover the hidden capacity for producing polyketides and terpenoids. Genome mining directed predictive framework reveals a diverse network of sesquiterpene synthases (STSs). Among twelve putative STSs encoded in the genome, six ones are belonging to the novel minor group: diverse Clade IV. In addition, RNA-sequencing based transcriptomic profiling revealed differentially expressed genes (DEGs) of the fungus CPCC 401429 in three different fermentation conditions, that of which enable us to identify noteworthy genes exemplified as STSs coding genes. Among the ten sesquiterpene biosynthetic DEGs, two genes including DtSTS9 and DtSTS10 were selected for functional characterization. Yeast cells expressing DtSTS9 and DtSTS10 could produce diverse sesquiterpene compounds, reinforced that STSs in the group Clade IV might be highly promiscuous producers. This highlights the potential of Desarmillaria in generating novel terpenoids. To summarize, our analyses will facilitate our understanding of phylogeny, STSs diversity and functional significance of Desarmillaria species. These results will encourage the scientific community for further research on uncharacterized STSs of Basidiomycota phylum, biological functions, and potential application of this vast source of secondary metabolites.

Pangenome analysis of the genus Herbiconiux and proposal of four new species associated with Chinese medicinal plants.

Five Gram-stain-positive, aerobic, non-motile actinobacterial strains designated as CPCC 205763T, CPCC 203386T, CPCC 205716T, CPCC 203406T, and CPCC 203407 were obtained from different ecosystems associated with four kinds of Chinese traditional medicinal plants. The 16S rRNA gene sequences of these five strains showed closely related to members of the genus Herbiconiux of the family Microbacteriaceae, with the highest similarities of 97.4-99.7% to the four validly named species of Herbiconiux. In the phylogenetic trees based on 16S rRNA gene sequences and the core genome, these isolates clustered into the clade of the genus Herbiconiux within the lineage of the family Microbacteriaceae. The overall genome relatedness indexes (values of ANI and dDDH) and the phenotypic properties (morphological, physiological and chemotaxonomic characteristics) of these isolates, readily supported to affiliate them to the genus Herbiconiux, representing four novel species, with the isolates CPCC 203406T and CPCC 203407 being classified in the same species. For which the names Herbiconiux aconitum sp. nov. (type strain CPCC 205763T = I19A-01430T = CGMCC 1.60067T), Herbiconiux daphne sp. nov. (type strain CPCC 203386T = I10A-01569T = DSM 24546T = KCTC 19839T), Herbiconiux gentiana sp. nov. (type strain CPCC 205716T = I21A-01427T = CGMCC 1.60064T), and Herbiconiux oxytropis sp. nov. (type strain CPCC 203406T = I10A-02268T = DSM 24549T = KCTC 19840T) were proposed, respectively. In the genomes of these five strains, the putative encoding genes for amidase, endoglucanase, phosphatase, and superoxidative dismutase were retrieved, which were classified as biosynthetic genes/gene-clusters regarding plant growth-promotion (PGP) functions. The positive results from IAA-producing, cellulose-degrading and anti-oxidation experiments further approved their potential PGP bio-functions. Pangenome analysis of the genus Herbiconiux supported the polyphasic taxonomy results and confirmed their bio-function potential.

Identification of Key Biomarkers and Candidate Molecules in Non-Small-Cell Lung Cancer by Integrated Bioinformatics Analysis.

Background: Non-small cell lung cancer (NSCLC) is the most prevalent malignant tumor of the lung cancer, for which the molecular mechanisms remain unknown. In this study, we identified novel biomarkers associated with the pathogenesis of NSCLC aiming to provide new diagnostic and therapeutic approaches for NSCLC by bioinformatics analysis. Methods: From the Gene Expression Omnibus database, GSE118370 and GSE10072 microarray datasets were obtained. Identifying the differentially expressed genes (DEGs) between lung adenocarcinoma and normal samples was done. By using bioinformatics tools, a protein-protein interaction (PPI) network was constructed, modules were analyzed, and enrichment analyses were performed. The expression and prognostic values of 14 hub genes were validated by the GEPIA database, and the correlation between hub genes and survival in lung adenocarcinoma was assessed by UALCAN, cBioPortal, String and Cytoscape, and Timer tools. Results: We found three genes (PIK3R1, SPP1, and PECAM1) that have a clear correlation with OS in the lung adenocarcinoma patient. It has been found that lung adenocarcinoma exhibits high expression of SPP1 and that this has been associated with poor prognosis, while low expression of PECAM1 and PIK3R1 is associated with poor prognosis (P < 0.05). We also found that the expression of SPP1 was associated with miR-146a-5p, while the high expression of miR-146a-5p was related to good prognosis (P < 0.05). On the contrary, the lower miR-21-5p on upstream of PIK3R1 is associated with a higher surviving rate in cancer patients (P < 0.05). Finally, we found that the immune checkpoint genes CD274(PD-L1) and PDCD1LG2(PD-1) were also related to SPP1 in lung adenocarcinoma. Conclusions: The results indicated that SPP1 is a cancer promoter (oncogene), while PECAM1 and PIK3R1 are cancer suppressor genes. These genes take part in the regulation of biological activities in lung adenocarcinoma, which provides a basis for improving detection and immunotherapeutic targets for lung adenocarcinoma.

Metabolites from the plant endophytic fungus Penicillium sp. CPCC 401423 and their cytotoxic activity against MIA PaCa-2 cells.

Twenty-two metabolites were isolated from Penicillium sp. CPCC 401423 cultured on rice. The structures of all compounds were elucidated mainly by MS and NMR analysis as well as the necessary CD experimental evidence, of which penicillidione A (1), penicillidione B (2), (E)-4-[(4-acetoxy-3-methyl-2-butenyl)oxy]phenylacetic acid (3), (S)-2-hydroxy-2-{4-[(3-methyl-2-butenyl)oxy]phenyl} (4), (S)-4-(2,3-dihydroxy-3-methyl-butoxy)phenylacetic acid (5), (E)-4-[(3-carboxy-2-butenyl)oxy]benzoic acid (6), (Z)-4-[(4-hydroxy-3-methyl-2-butenyl)oxy]benzoic acid (7), open-cycled N-demethylmelearoride A (12), and penostatin M (16) were identified as new compounds. The cytotoxic activity against human pancreatic carcinoma cell line MIA PaCa-2a was detected. Among them, compounds 13-15 and 22 displayed significant cytotoxicity against MIA-PaCa-2 cells with IC50 values of 8.9, 36.5, 31.8, and 22.3 µM, respectively (positive control gemcitabine IC50 65.0 µM).

Corrigendum: Pangenome analysis of the genus Herbiconiux and proposal of four new species associated with Chinese medicinal plants.

[This corrects the article DOI: 10.3389/fmicb.2023.1119226.].

Trichostatin D as a Novel KLF2 Activator Attenuates TNFα-Induced Endothelial Inflammation.

Krüppel-like factor 2 (KLF2) is an atherosclerotic protective transcription factor that maintains endothelial cell homeostasis through its anti-inflammatory, anti-oxidant, and antithrombotic properties. The aim of this study was to discover KLF2 activators from microbial secondary metabolites and explore their potential molecular mechanisms. By using a high-throughput screening model based on a KLF2 promoter luciferase reporter assay, column chromatography, electrospray ionization mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR) spectra, trichostatin D (TSD) was isolated from the rice fermentation of Streptomyces sp. CPCC203909 and identified as a novel KLF2 activator. Real-time-quantitative polymerase chain reaction (RT-qPCR) results showed that TSD upregulated the mRNA level of KLF2 in endothelial cells. Functional assays showed that TSD attenuated monocyte adhesion to endothelial cells, decreased vascular cell adhesion protein 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) expression, and exhibited an anti-inflammatory effect in tumor necrosis factor alpha (TNFα)-induced endothelial cells. We further demonstrated through siRNA and western blot assays that the effects of TSD on monocyte adhesion and inflammation in endothelial cells were partly dependent on upregulating KLF2 expression and then inhibiting the NOD-like receptor protein 3 (NLRP3)/Caspase-1/interleukin-1beta (IL-1ß) signaling pathway. Furthermore, histone deacetylase (HDAC) overexpression and molecular docking analysis results showed that TSD upregulated KLF2 expression by inhibiting HDAC 4, 5, and 7 activities. Taken together, TSD was isolated from the fermentation of Streptomyces sp. CPCC203909 and first reported as a potential activator of KLF2 in this study. Furthermore, TSD upregulated KLF2 expression by inhibiting HDAC 4, 5, and 7 and attenuated endothelial inflammation via regulation of the KLF2/NLRP3/Caspase-1/IL-1ß signaling pathway.

Shinella lacus sp. nov., a novel microcystin-degrading alphaproteobacterium containing the bla carbapenemase gene.

A Gram-stain-negative, rod-shaped, microcystin-degrading bacterium, designated as CPCC 100929T, was isolated from a fresh water reservoir in Sichuan Province, PR China. This isolate grew well at 4-37 °C and pH 6.0-8.0, with optimal growth at 28-32 °C and pH 7.0, respectively. The major cellular fatty acids were C18:1 ω7c/C18:1 ω6c, C16:0, C18:1 ω7c 11-methyl and C19:0 cyclo ω8c. The predominant respiratory quinone was Q-10. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine and phosphatidylcholine were detected in the polar lipids extraction. The 16S rRNA gene sequence of strain CPCC 100929T was closely related to those of members of the genus Shinella, with the highest similarity of 98.6 % to Shinella zoogloeoides DSM 287T and 97.4-98.4 % with other identified Shinella members. In the phylogenetic trees based on 16S rRNA gene sequences and the core-genes analysis, strain CPCC 100929T was included within the clade of the genus Shinella. The values of average nucleotide identity (81.4-86.7 %) and digital DNA-DNA hybridization (25.4-44.6 %) between strain CPCC 100929T and other Shinella species were all below the thresholds for bacterial species delineation, respectively. The genomic DNA G+C content of strain CPCC 100929T was 63.6 %. The genomic sequence analysis indicated that this species contained genes encoding peroxidase, bla carbapenemase and the key enzyme for microcystin bio degradation, as well as rich carbohydrate-active enzyme coding genes, which might endow the micro-organism with properties to adapt to diverse environments. Based on its phenotypic and genetic properties, we propose that strain CPCC 100929T (=T1A350T=KCTC 72957T) is the type strain of a novel species with the name Shinella lacus sp. nov.

A Combination of Genome Mining with an OSMAC Approach Facilitates the Discovery of and Contributions to the Biosynthesis of Melleolides from the Basidiomycete Armillaria tabescens.

Genome mining revealed that the genomes of basidiomycetes may include a considerable number of biosynthetic gene clusters (BGCs), yet numerous clusters remain unidentified. Herein, we report a combination of genome mining with an OSMAC (one strain, many compounds) approach to characterize the spectrum of melleolides produced by Armillaria tabescens CPCC 401429. Using F1 fermentation medium, the metabolic pathway of the gene cluster mel was successfully upregulated. From the extracts of the wild-type strain, two new melleolides (1 and 2), along with five new orsellinic acid-derived lactams (10-14), were isolated, and their structures were elucidated by LC-HR-ESIMS/MS and 2D-NMR. Several melleolides exhibited moderate anti-carcinoma (A549, NCI-H520, and H1299) effects with IC50 values of 4.0-48.8 µM. RNA-sequencing based transcriptomic profiling broadened our knowledge of the genetic background, regulation, and mechanisms of melleolide biosynthesis. These results may promote downstream metabolic engineering studies of melleolides. Our study demonstrates the approach is effective for discovering new secondary metabolites from Armillaria sp. and will facilitate the mining of the unexploited biosynthetic potential in other basidiomycetes.

Prenylemestrins A and B: Two Unexpected Epipolythiodioxopiperazines with a Thioethanothio Bridge from Emericella sp. Isolated by Genomic Analysis.

Prenylemestrins A and B (1 and 2, respectively), two unusual epipolythiodioxopiperazines featuring a thioethanothio bridge instead of a polysulfide bridge, were isolated from the fungus Emericella sp. CPCC 400858 guided by genomic analysis. Their structures were determined by extensive spectroscopic data, NMR and ECD calculations, and X-ray diffraction analysis. A plausible biosynthetic pathway for 1 and 2 was proposed on the basis of gene cluster analysis. Prenylemestrins A and B exhibited cytotoxicities against human chronic myelocytic leukemia cell lines K562 and MEG-01.

Ac-LysargiNase efficiently helps genome reannotation of Mycolicibacterium smegmatis MC2 155.

Accurate genome annotation, the foundation of life science research in the genome era, is hampered by limited known gene models, nonstandard start codons, and the limited homology of annotated genes in other organisms. LysargiNase mirrors trypsin at the cleavage sites, providing the opportunity to identify peptides other than tryptic peptides. In this study, we used an in-house developed acetylated LysargiNase (Ac-LysargiNase) with higher activity and stability in non-pathogenic Mycolicibacterium smegmatis MC2 155 to supplement the widely used trypsin in proteomic studies. We identified 27,582 peptides from 3844 annotated proteins and 332 novel genome search-specific peptides (GSSPs). Among these GSSPs, 88 peptides were annotated in another M.smegmatis genome database, and 41 were verified as novel peptides by predicted theoretical spectra and their corresponding 15N-labeling spectra. Further analysis revealed that 17 verified GSSPs corrected the N-terminus of the 13 annotated genes. The other 24 verified GSSPs helped identify 17 novel open reading frames (ORFs) missed in previously annotated M. smegmatis genomes. Among these novel ORFs, four relatively small proteins with amino acid residues less than 100 and three were precisely identified with C-terminal peptides. Ac-LysargiNase helps with genome reannotation by identifying new genes and events in proteogenomic studies. SIGNIFICANCE: Correct genomic annotation is vital in the field of life sciences. The nonstandard start codons seriously affect the confirmation of the translation initiation sites (TISs) of an open reading frame (ORF), and unknown structural genes are easily missed in automated gene prediction. Although proteogenomics presents new avenues for validating gene expression and gene structure refinement based on conventional tryptic peptides, determining the TISs and potential encoding genes is complicated. Thus, validation of TISs and encoding ORFs is crucial and urgent. Therefore, we recommend Ac-LysargiNase, a mirror enzyme of trypsin that can identify additional novel peptides for N-terminal correction and ORF identification.

Hydrogen-assisted synthesis of Ni-ZIF-derived nickel nanoparticle chains coated with nitrogen-doped graphitic carbon layers as efficient electrocatalysts for non-enzymatic glucose detection.

Chains of nickel nanoparticles coated with few nitrogen-doped graphitic carbon layers (Ni@NC) are synthesized by hydrogen-assisted pyrolysis of Ni-ZIF. Hydrogen and temperature can play key roles in the formation of oriented Ni@NC nanoparticle chains, and carbon shells can protect Ni nanoparticles from external oxidation and aggregations. Under the optimized potential (0.60 V vs. Ag/AgCl), the Ni@NC7H nanoparticle chains obtained at 700 °C under H2/Ar atmosphere (Ni@NC7H) demonstrate outstanding performances, such as high sensitivity of 1.44 mA mM-1 cm-2 (RSD = 1.0%), low detection limit of 0.34 µM (S/N = 3), broad linear range from 1 µM to 1.81 mM, and excellent application potential in artificial sweat and human serum. Therefore, the findings above indicate that this study will provide a general methodology for the synthesis of chains-like core-shell nanoparticle electrocatalysts for non-enzymatic glucose detection.