Bacillaene, sharp objects consist in the arsenal of antibiotics produced by Bacillus.

Bacillus species act as plant growth-promoting rhizobacteria (PGPR) that can produce a large number of bioactive metabolites. Bacillaene, a linear polyketide/nonribosomal peptide produced by Bacillus strains, is synthesized by the trans-acyltransferase polyketide synthetase. The complexity of the chemical structure, particularity of biosynthesis, potent bioactivity, and the important role of competition make Bacillus an ideal antibiotic weapon to resist other microbes and maintain the optimal rhizosphere environment. This review provides an updated view of the structural features, biological activity, biosynthetic regulators of biosynthetic pathways, and the important competitive role of bacillaene during Bacillus survival.

Anti-Inflammatory Effects of New Naphthyridine from Sponge Aaptos suberitoides in LPS-Stimulated RAW 264.7 Macrophages via Regulation of MAPK and Nrf2 Signaling Pathways.

Two new naphthyridine compounds, 4-methoxycarbonyl-5-oxo-1,6-naphthyridine (1) and 5-methoxycarbonyl-4-oxo-1,6-naphthyridine (2) were obtained from the MeOH extracts of sponge Aaptos suberitoides. Their structures were determined by spectroscopic methods, including HR-ESI-MS, 1D-NMR (1 H-NMR, 13 C-NMR), 2D-NMR (COSY, HSQC, HMBC). The structure of compound 1 was further confirmed via single crystal X-ray diffraction analysis. Compound 1 was found to reduce NO production in LPS-induced RAW 264.7 macrophages with IC50 value of 0.15 mM. In addition, it decreased the mRNA expression levels of pro-inflammatory mediators, such as the tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) in LPS-induced macrophages. It also decreased the protein expression of iNOS and COX-2 in LPS-induced macrophages. Mechanistic studies further revealed that compound 1 inhibited the mitogen-activated protein kinase (MAPK), and activated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathways in LPS-induced RAW 264.7 macrophages.

Identification of OSCA gene family in Solanum habrochaites and its function analysis under stress.

BACKGROUND: OSCA (hyperosmolality-gated calcium-permeable channel) is a calcium permeable cation channel protein that plays an important role in regulating plant signal transduction. It is involved in sensing changes in extracellular osmotic potential and an increase in Ca2+ concentration. S. habrochaites is a good genetic material for crop improvement against cold, late blight, planthopper and other diseases. Till date, there is no report on OSCA in S. habrochaites. Thus, in this study, we performed a genome-wide screen to identify OSCA genes in S. habrochaites and characterized their responses to biotic and abiotic stresses. RESULTS: A total of 11 ShOSCA genes distributed on 8 chromosomes were identified. Subcellular localization analysis showed that all members of ShOSCA localized on the plasma membrane and contained multiple stress-related cis acting elements. We observed that genome-wide duplication (WGD) occurred in the genetic evolution of ShOSCA5 (Solhab04g250600) and ShOSCA11 (Solhab12g051500). In addition, repeat events play an important role in the expansion of OSCA gene family. OSCA gene family of S. habrochaites used the time lines of expression studies by qRT-PCR, do indicate OSCAs responded to biotic stress (Botrytis cinerea) and abiotic stress (drought, low temperature and abscisic acid (ABA)). Among them, the expression of ShOSCAs changed significantly under four stresses. The resistance of silencing ShOSCA3 plants to the four stresses was reduced. CONCLUSION: This study identified the OSCA gene family of S. habrochaites for the first time and analyzed ShOSCA3 has stronger resistance to low temperature, ABA and Botrytis cinerea stress. This study provides a theoretical basis for clarifying the biological function of OSCA, and lays a foundation for tomato crop improvement.

Aaptamine - a dual acetyl - and butyrylcholinesterase inhibitor as potential anti-Alzheimer's disease agent.

CONTEXT: Alzheimer's disease (AD) is a neurodegenerative disorder that affects millions of people worldwide. Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) are promising therapeutic targets for AD. OBJECTIVE: To evaluate the inhibitory effects of aaptamine on two cholinesterases and investigate the in vivo therapeutic effect on AD in a zebrafish model. MATERIALS AND METHODS: Aaptamine was isolated from the sponge Aaptos suberitoides Brøndsted (Suberitidae). Enzyme inhibition, kinetic analysis, surface plasmon resonance (SPR) and molecular docking assays were used to determine its inhibitory effect on AChE and BuChE in vitro. Zebrafish were divided into six groups: control, model, 8 µM donepezil, 5 , 10 and 20 µM aaptamine. After three days of drug treatment, the behaviour assay was performed. RESULTS: The IC50 values of aaptamine towards AChE and BuChE were 16.0 and 4.6 µM. And aaptamine directly inhibited the two cholinesterases in the mixed inhibition type, with Ki values of 6.96 ± 0.04 and 6.35 ± 0.02 µM, with Kd values of 87.6 and 10.7 µM. Besides, aaptamine interacts with the crucial anionic sites of AChE and BuChE. In vivo studies indicated that the dyskinesia recovery rates of 5 , 10 and 20 µM aaptamine group were 34.8, 58.8 and 60.0%, respectively, and that of donepezil was 63.7%. DISCUSSION AND CONCLUSIONS: Aaptamine showed great potential to exert its anti-AD effects by directly inhibiting the activities of AChE and BuChE. Therefore, this study identified a novel medicinal application of aaptamine and provided a new structural scaffold for the development of anti-AD drugs.

Species and geographic specificity between endophytic fungi and host supported by parasitic Cynomorium songaricum and its host Nitraria tangutorum distributed in desert.

This study was aimed to investigate whether host plant species and lifestyles, and environmental conditions in the desert affect endophytic fungi composition. Endophytic fungal communities from parasitic plant Cynomorium songaricum and its host Nitraria tangutorum were investigated from three sites including Tonggu Naoer, Xilin Gaole, and Guazhou in Tengger and Badain Jaran Deserts in China using the next-generation sequencing of a ribosomal RNA gene region. Similarity and difference in endophytic fungal composition from different geographic locations were evaluated through multivariate statistical analysis. It showed that plant genetics was a deciding factor affecting endophytic fungal composition even when C. songaricum and N. tangutorum grow together tightly. Not only that, the fungal composition was also greatly affected by the local environment and rainfall. However, the distribution and richness of fungal species indicated that the geographical distance exerted little influence on characterizing the fungal composition. Overall, the findings suggested that plant species, parasitic or non-parasitic lifestyles of the plant, and local environment strongly affected the number and diversity of the endophytic fungal species, which may provide valuable insights into the microbe ecology, symbiosis specificity, and the tripartite relationship among parasitic plant, host, and endophytic fungi, especially under desert environment.

m6A demethylase ALKBH5 inhibits tumor growth and metastasis by reducing YTHDFs-mediated YAP expression and inhibiting miR-107/LATS2-mediated YAP activity in NSCLC.

BACKGROUND: The importance of mRNA methylation erased by ALKBH5 in mRNA biogenesis, decay, and translation control is an emerging research focus. Ectopically activated YAP is associated with the development of many human cancers. However, the mechanism whereby ALKBH5 regulates YAP expression and activity to inhibit NSCLC tumor growth and metastasis is not clear. METHODS: Protein and transcript interactions were analyzed in normal lung cell and NSCLC cells. Gene expression was evaluated by qPCR and reporter assays. Protein levels were determined by immunochemical approaches. Nucleic acid interactions and status were analyzed by immunoprecipitation. Cell behavior was analyzed by standard biochemical tests. The m6A modification was analyzed by MeRIP. RESULTS: Our results show that YAP expression is negatively correlated with ALKBH5 expression and plays an opposite role in the regulation of cellular proliferation, invasion, migration, and EMT of NSCLC cells. ALKBH5 reduced m6A modification of YAP. YTHDF3 combined YAP pre-mRNA depending on m6A modification. YTHDF1 and YTHDF2 competitively interacted with YTHDF3 in an m6A-independent manner to regulate YAP expression. YTHDF2 facilitated YAP mRNA decay via the AGO2 system, whereas YTHDF1 promoted YAP mRNA translation by interacting with eIF3a; both these activities are regulated by m6A modification. Furthermore, ALKBH5 decreased YAP activity by regulating miR-107/LATS2 axis in an HuR-dependent manner. Further, ALKBH5 inhibited tumor growth and metastasis in vivo by reducing the expression and activity of YAP. CONCLUSIONS: The presented findings suggest m6A demethylase ALKBH5 inhibits tumor growth and metastasis by reducing YTHDFs-mediated YAP expression and inhibiting miR-107/LATS2-mediated YAP activity in NSCLC. Moreover, effective inhibition of m6A modification of ALKBH5 might constitute a potential treatment strategy for lung cancer.

Evaluation of the protective immunity of Riemerella anatipestifer OmpA.

Riemerella anatipestifer is responsible for an economically important disease of commercially raised ducks. No or only few cross-protection was observed between different serotypes of R. anatipestifer strains, and so far no protective antigen in this bacterium has been identified. OmpA is a predominant immunogenic protein of R. anatipestifer, and within the 1467 bp ompA ORF (ompA1467), there is another 1164 bp ORF (ompA1164) with the same C-terminal. In this study, our results showed that the full sequence of ompA1467 from some R. anatipestifer strains with different serotypes shared the same amino acid sequence. Animal experiments showed that the soluble recombinant protein rOmpA1164, but not rOmpA1467, could provide partial protective immunity against challenge. Moreover, there was no significant difference in protective immunity between ducklings immunized with Th4△ompA bacterin and those immunized with Th4 bacterin. In addition, OmpA1467 was the main existing form of OmpA in R. anatipestifer cells by gel electrophoresis and western blot analyses. The results suggested that OmpA1467 was not a protective antigen of R. anatipestifer, and antibodies against proteins other than OmpA play a critical role in the process of anti-R. anatipestifer infection.

Engineering plants to secrete affinity-tagged pathogen elicitors for deciphering immune receptor complex or inducing enhanced immunity.

Plant cells mount plenty of pattern-recognition receptors (PRRs) to detect the microbe-associated molecular patterns (MAMPs) from potential microbial pathogens. MAMPs are overrepresented by proteinaneous patterns, such as the flg22 peptide from bacterial flagellin. Identification of PRR receptor complex components by forward or reverse genetics can be time/labor-consuming, and be confounded by functional redundancies. Here, we present a strategy for identifying PRR complex components by engineering plants to inducibly secrete affinity-tagged proteinaneous MAMPs to the apoplast. The PRR protein complexes bound to self-secreted MAMPs are enriched through affinity purification and dissected by mass spectrometry. As a proof of principle, we could capture the flg22 receptor FLS2 and co-receptor BAK1 using Arabidopsis plants secreting FLAG-tagged flg22 under estradiol induction. Moreover, we identified receptor-like kinases LIK1 and PEPR1/PEPR2 as potential components in the FLS2 receptor complex, which were further validated by protein-protein interaction assays and the reverse genetics approach. Our study showcases a simple way to biochemically identify endogenous PRR complex components without overexpressing the PRR or using chemical cross-linkers, and suggests a possible crosstalk between different immune receptors in plants. A modest dose of estradiol can also be applied to inducing enhanced immunity in engineered plants to both bacterial and fungal pathogens.

Aaptamine attenuates the proliferation and progression of non-small cell lung carcinoma.

CONTEXT: Aaptamine is a potent ocean-derived non-traditional drug candidate against human cancers. However, the underlying molecular mechanisms governing aaptamine-mediated repression of lung cancer cells remain largely undefined. OBJECTIVE: To examine the inhibitory effect of aaptamine on proliferation and progression of non-small cell lung carcinoma (NSCLC) and dissect the potential mechanisms involved in its anticancer functions. MATERIALS AND METHODS: In vitro assays of cell proliferation, cell cycle analysis, clonal formation, apoptosis and migration were performed to examine the inhibitory effects of aaptamine (8, 16 and 32 µg/mL) on NSCLC cells. The expression levels of proteins were analysed using western blotting analysis when cells were treated with a single drug or a combination treatment for 48 h. RESULTS: Aaptamine significantly inhibited A549 and H1299 cells proliferation with IC50 values of 13.91 and 10.47 µg/mL. At the concentrations of 16 and 32 µg/mL, aaptamine significantly reduced capacities in clonogenicity, enhanced cellular apoptosis and decreased the motile and invasive cellular phenotype. In addition, aaptamine arrested cell cycle at G1 phase via selectively abating cell cycle regulation drivers (CDK2/4 and Cyclin D1/E). Western blotting results showed that aaptamine attenuated the protein expression of MMP-7, MMP-9 and upregulated the expression of cleaved-PARP and cleaved-caspase 3. Moreover, aaptamine inhibited PI3K/AKT/GSK3ß signalling cascades through specifically degrading the phosphorylated AKT and GSK3ß. DISCUSSION AND CONCLUSIONS: Aaptamine retarded the proliferation and invasion of NSCLC cells by selectively targeting the pathway PI3K/AKT/GSK3ß suggesting it as a potential chemotherapeutic agent for repressing tumorigenesis and progression of NSCLC in humans.

Roles of the TonB1 and TonB2 proteins in haemin iron acquisition and virulence in Riemerella anatipestifer.

Two TonB systems in Riemerella anatipestifer were found and characterized as ExbB1-ExbD1-TonB1 and ExbB2-ExbD2-ExbD2'-TonB2, but the significance of two sets of TonB complexes in R. anatipestifer is not clear. In this study, by deleting the tonB1 or tonB2 gene of R. anatipestifer strain CH3, we investigated the roles of the TonB1 and TonB2 proteins in iron acquisition and virulence. The results showed that strain CH3 could utilize haemin as the sole iron source in the presence of l-cysteine, but haemin iron acquisition was defective in the CH3ΔtonB1 mutant, and the deletion of either tonB1 or tonB2 significantly reduced adhesion to and invasion of Vero cells. Animal experiments indicated that the LD50 of the CH3ΔtonB1 and CH3ΔtonB2 mutants in ducklings was ∼224- and ∼87-fold, respectively, higher than that of the WT CH3 strain. Additional analysis indicated that blood bacterial loading of ducklings infected with CH3ΔtonB1 or CH3ΔtonB2 decreased significantly compared with that found for WT CH3-infected ducklings. Thus, our results indicated that the TonB1, but not TonB2 protein, is involved in haemin iron acquisition and that both TonB proteins are necessary for optimal bacterial virulence.

Chemical constituents from the seeds of Cullen corylifolium and their inhibitory activity on diacylglycerol acyltransferase.

A large number of extracts of medicinal plants or natural products shows beneficial to combat obesity. In the present work, a new flavonoid named (2S,1″R,2″R)-4'-hydroxy-7-methoxy-6-(1,2,3-trihydroxy-3-methyl-butyl)-flavanone (1), along with seven known compounds (2-8) were isolated from the seeds of Cullen corylifolium. Their structures, including the absolute configurations, were determined by the analysis of comprehensive spectroscopic data and computational calculation methods. All isolates were evaluated for their diacylglycerol acyltransferase (DGAT) inhibitory activity. Compounds 1-4 exhibited different level of DGAT1 inhibitory activity with IC50 values ranging from 28.2 ± 1.1 to 127.3 ± 1.9 µM. In addition, 45 flavonoids which be evaluated for DGAT inhibitory activity were summarised and potential structure-activity relationships were discussed.

Microbiome - based agents can optimize composting of agricultural wastes by modifying microbial communities.

Microorganisms that facilitate the decomposition of agricultural wastes are of importance during composting processes. Here, we assessed if microbial agents, comprising Clonostachys rosea, Bacillus amylolyticus and Rhodospirillum photometricum can facilitate the decomposition of a compost mix of vegetable waste, chicken manure, sawdust, and biochar. The results showed that inoculating the compost mix with the microbial agents elevated the compost temperature, increased the thermophilic period, and enhanced cellulose degradation. Microbial agent inoculation also changed the diversity and richness of decomposing microbial communities. Among the microbial agents, the mixture of C. rosea and B. amylolyticus performed better than other mixtures. Taken together, the results confirmed that the microbial agents comprising C. rosea can enhance the composting process by ameliorating the physiochemical conditions of agricultural wastes and promoting the diversity and proliferation of beneficial bacteria involved in the decomposition of cellulose.

Biocontrol endophytes Bacillus subtilis R31 influence the quality, transcriptome and metabolome of sweet corn.

During colonization of soil and plants, biocontrol bacteria can effectively regulate the physiological metabolism of plants and induce disease resistance. To illustrate the influence of Bacillus subtilis R31 on the quality, transcriptome and metabolome of sweet corn, field studies were conducted at a corn experimental base in Zhuhai City. The results show that, after application of B. subtilis R31, sweet corn was more fruitful, with a 18.3 cm ear length, 5.0 cm ear diameter, 0.4 bald head, 403.9 g fresh weight of single bud, 272.0 g net weight of single ear, and 16.5 kernels sweetness. Combined transcriptomic and metabolomic analyses indicate that differentially expressed genes related to plant-pathogen interactions, MAPK signaling pathway-plant, phenylpropanoid biosynthesis, and flavonoid biosynthesis were significantly enriched. Moreover, the 110 upregulated DAMs were mainly involved in the flavonoid biosynthesis and flavone and flavonol biosynthesis pathways. Our study provides a foundation for investigating the molecular mechanisms by which biocontrol bacteria enhance crop nutrition and taste through biological means or genetic engineering at the molecular level.

The composition characteristics of endophytic communities and their relationship with metabolites profile in Ephedra sinica under wild and cultivated conditions.

Ephedra sinica is one of the most famous Chinese medicinal plants. The insufficient supply of wild resources has led to the increased use of cultivated products. However, the related medicinal quality differs significantly. Although the influence of external environment on the quality of E. sinica has been studied, the impact of endophytic microbes on it remains vague. This study characterized differential metabolites and microbial community compositions in wild and cultivated E. sinica by combining metabolomics with microbiomics, and explored the effect of endophytes on the formation of differential metabolites further. The results showed that the difference in quality between wild and cultivated E. sinica was mainly in the productions of alkaloids, flavonoids, and terpenoids. The associated endophytes had special compositional characteristics. For instance, the distribution and abundance of dominant endophytes varied between wild and cultivated E. sinica. Several endophytes had significant or highly significant correlations with the formations of ephedrine, pseudoephedrine, D-cathinone, methcathinone, coumarin, kaempferol, rhamnetin, or phenylacetic acid. This study will deepen our understanding of the plant-endophyte interactions and provide a strategy for the quality control of E. sinica products.

Biocontrol of bacterial wilt disease in tomato using Bacillus subtilis strain R31.

Bacterial wilt disease caused by Ralstonia solanacearum is a widespread, severe plant disease. Tomato (Solanum lycopersicum), one of the most important vegetable crops worldwide, is particularly susceptible to this disease. Biological control offers numerous advantages, making it a highly favorable approach for managing bacterial wilt. In this study, the results demonstrate that treatment with the biological control strain Bacillus subtilis R31 significantly reduced the incidence of tomato bacterial wilt. In addition, R31 directly inhibits the growth of R. solanacearum, and lipopeptides play an important role in this effect. The results also show that R31 can stably colonize the rhizosphere soil and root tissues of tomato plants for a long time, reduce the R. solanacearum population in the rhizosphere soil, and alter the microbial community that interacts with R. solanacearum. This study provides an important theoretical basis for elucidating the mechanism of B. subtilis as a biological control agent against bacterial wilt and lays the foundation for the optimization and promotion of other agents such as R31.

[SOX2-OT/SOX2 axis regulates lung cancer H520 cell migration via Gli1-mediated epithelial-mesenchymal transition].

OBJECTIVE: To explore the regulatory role of SOX2-OT in migration of lung squamous cell carcinoma H520 cells and the underlying mechanisms. METHODS: Wound- healing and Transwell migration assays were performed to examine the changes in migration and invasion capacity of lung squamous cell line H520, which expressed higher levels of SOX2-OT than other lung cancer cell lines, following RNA interference-mediated SOX2-OT knockdown. The transcription levels of epithelial-mesenchymal transition (EMT)-related components was detected by qRT-PCR and immunoblotting. Gli1 gain-of-function analysis was performed in H520 cells with SOX2-OT knockdown and the changes in EMT phenotype of the cells were examined. miR-200c mimic and inhibitor were used to analyze the mechanism by which SOX2-OT positively regulates Gli1 and the mediating role of SOX2. RESULTS: SOX2-OT knockdown significantly lowered the invasiveness and migration capacity of H520 cells and caused changes in EMT phenotype of the cells. Overexpression of Gli1, which was positively regulated by SOX2-OT, reversed the inhibitory effect of SOX2-OT knockdown on migration of H520 cells. Transfection of the cells with miR-200c inhibitor effectively reversed SOX2-OT knockdown-induced down-regulation of SOX2. CONCLUSION: The SOX2-OT/SOX2 axis positively regulates migration of lung squamous H520 cells via Gli1-mediated EMT.

Transcriptional Regulatory Mechanism of Differential Metabolite Formation in Root and Stem of Ephedra sinica.

Ephedra sinica, a well-known Chinese medicinal plant, is characterized as having the opposite medicinal effect among its root and stem. However, there is a lack of understanding to differentiate the active components present in the root and stem of E. sinica, as well as the molecular mechanisms underlying the formation of the differential compounds, which has significantly hampered the further development and utilization of E. sinica resource. In this study, forty-five differential metabolic markers are affiliated to alkaloids, flavonoids, terpenoids, and organic acids between root and stem of E. sinica, and sixty genes of key enzymes are involved in their biosynthesis distributed in metabolic pathway branches such as phenylalanine metabolism, flavonoid biosynthesis and phenylpropane biosynthesis, based on combination non-targeted metabolome with transcriptome technologies. The finding revealed that the expression activity changes of these enzyme genes had a direct impact on the distinction of differential metabolic markers in the root and stem of E. sinica. This study will help to understand the molecular mechanism of the differentiation and biosynthesis of the primary active metabolites in the root and stem of E. sinica, providing a theoretical foundation for its quality control and promotion in cultivation.

Cytochalasins from coastal saline soil-derived fungus Aspergillus flavipes RD-13 and their cytotoxicities.

Chemical investigation of coastal saline soil-derived fungus Aspergillus flavipes RD-13 led to the isolation of two new seco-cytochalasins (1) and (2) along with nine known analogs. Their structures were elucidated by comprehensive spectral analysis, and the absolute configurations of these two new ones were determined through Rh2(OCOCF3)4-induced CD experiment and chemical interconversions. Moreover, the absolute configuration of a known compound named cytochalasins Z18 (3) was also determined for the first time. Structurally, compounds 1, 2 and 3 were the open ring derivatives of compounds 5, 8, and 4, respectively. All compounds were evaluated for their cytotoxic activities on A549, H1299 and H520 cells and 4 exhibited the strongest inhibitory activities towards the above cell lines with IC50 values of 0.15, 0.23 and 0.43 µg/mL, respectively. Preliminary structure-activity relationship analysis suggested the importance of macrocyclic ring in cytochalasins to confer cytotoxicity.

Aaptamine derivatives with CDK2 inhibitory activities from the South China Sea sponge Aaptos suberitoides.

Three new aaptamines (1-3) together with two known derivatives (4-5) were isolated from the South China Sea sponge Aaptos suberitoides. The structures of all compounds were unambiguously elucidated by spectroscopic analyses as well as the comparison with literature data. All the compounds were evaluated for their cytotoxic activities against five human cancer cell lines including H1299, H520, SCG7901, CNE-2 and SW680 cells. As a result, compounds 3-5 showed moderate cytotoxicities against H1299 and H520 cells with IC50 values ranging from 12.9 to 20.6 µg/mL. Besides, compounds 3-5 also showed potent inhibitory activities toward cyclin-dependent kinase-2 (CDK2) with IC50 values of 14.3, 3.0 and 6.0 µg/mL, respectively. In addition, compounds 3-5 significantly induced G1 arrests of H1299 cells at low concentrations. Drug affinity responsive target stability (DARTS) experiments were carried out and further demonstrated that compound 3 could effectively bind with CDK2 protein and protect it from the degradation by pronase.