Screening, identification, and mechanism analysis of starch-degrading bacteria during curing process in tobacco leaf.

Tobacco, a vital economic crop, had its quality post-curing significantly influenced by starch content. Nonetheless, the existing process parameters during curing were inadequate to satisfy the starch degradation requirements. Microorganisms exhibit inherent advantages in starch degradation, offering significant potential in the tobacco curing process. Our study concentrated on the microbial populations on the surface of tobacco leaves and in the rhizosphere soil. A strain capable of starch degradation, designated as BS3, was successfully isolated and identified as Bacillus subtilis by phylogenetic tree analysis based on 16SrDNA sequence. The application of BS3 on tobacco significantly enhanced enzyme activity and accelerated starch degradation during the curing process. Furthermore, analyses of the metagenome, transcriptome, and metabolome indicated that the BS3 strain facilitated starch degradation by regulating surface microbiota composition and affecting genes related to starch hydrolyzed protein and key metabolites in tobacco leaves. This study offered new strategies for efficiently improving the quality of tobacco leaves.

Positive GLI1/INHBA feedback loop drives tumor progression in gastric cancer.

GLI1, a key transcription factor of the Hedgehog (Hh) signaling pathway, plays an important role in the development of cancer. However, the function and mechanisms by which GLI1 regulates gene transcription are not fully understood in gastric cancer (GC). Here, we found that GLI1 induced the proliferation and metastasis of GC cells, accompanied by transcriptional upregulation of INHBA. This increased INHBA expression exerted a promoting activity on Smads signaling and then transcriptionally activated GLI1 expression. Notably, our results demonstrate that disrupting the interaction between GLI1 and INHBA could inhibit GC tumorigenesis in vivo. More intriguingly, we confirmed the N6-methyladenosine (m6A) activation mechanism of the Helicobacter pylori/FTO/YTHDF2/GLI1 pathway in GC cells. In conclusion, our study confirmed that the GLI1/INHBA positive feedback loop influences GC progression and revealed the mechanism by which H. pylori upregulates GLI1 expression through m6A modification. This positive GLI1/INHBA feedback loop suggests a novel noncanonical mechanism of GLI1 activity in GC and provides potential therapeutic targets for GC treatment.

Myricetin Induces Ferroptosis and Inhibits Gastric Cancer Progression by Targeting NOX4.

Ferroptosis holds great potential as a therapeutic approach for gastric cancer (GC), a prevalent and deadly malignant tumor associated with high rates of incidence and mortality. Myricetin, well-known for its multifaceted biomedical attributes, particularly its anticancer properties, has yet to be thoroughly investigated regarding its involvement in ferroptosis. The aim of this research was to elucidate the impact of myricetin on ferroptosis in GC progression. The present study observed that myricetin could trigger ferroptosis in GC cells by enhancing malondialdehyde production and Fe2+ accumulation while suppressing glutathione levels. Mechanistically, myricetin directly interacted with NADPH oxidase 4 (NOX4), influencing its stability by inhibiting its ubiquitin degradation. Moreover, myricetin regulated the inhibition of ferroptosis induced by Helicobacter pylori cytotoxin-associated gene A (CagA) through the NOX4/NRF2/GPX4 pathway. In vivo experiments demonstrated that myricetin treatment significantly inhibited the growth of subcutaneous tumors in BALB/c nude mice. It was accompanied by increased NOX4 expression in tumor tissue and suppression of the NRF2/GPX4 antioxidant pathway. Therefore, this research underscores myricetin as a novel inducer of ferroptosis in GC cells through its interaction with NOX4. It is a promising candidate for GC treatment.

Revealing the Mechanistic Basis of Regulation of Phosphorus Uptake in Soybean (Glycine max) Roots by Molybdenum: An Integrated Omics Approach.

While molybdenum (Mo) application can improve phosphorus (P) availability to plants by changing P speciation in the rhizosphere, the mechanistic basis of this process remains unclear. This work investigated the impact of various combinations of Mo and P treatments on root morphology, P and Mo uptake, and root transcriptome and metabolome. Mo application significantly increased soybean biomass and the number of lateral roots at both low (5 µmol) or normal (500 µmol) P levels and significantly improved P concentration and accumulation in Normal P treatment. Compared with the Normal P treatment, Low P significantly increased the number of roots, root surface area, and root acid phosphatase secretion. A total of 6811 Mo-responsive differentially expressed genes and 135 differential metabolites were identified at two P levels. At Low P, transcriptional changes significantly increased root synthesis and secretion of succinic acid, methylmalonic acid, and other organic acids as well as acid phosphatase, thereby increasing the conversion of soil aluminum-bound P and organic P into available P. At Normal P, Mo application increased P uptake mainly by increasing the number of lateral roots. Thus, Mo helps crops adapt to different P levels by regulating root anatomy and transcriptional and metabolic profiles of their roots.

The role of phosphorus speciation of biochar in reducing available Cd and phytoavailability in mining area soil: Effect and mechanism.

The effect of phosphorus (P) speciation in biochar on soil available Cd and its mechanism to alleviate plant Cd stress remain largely unknown. Here, ammonium polyphosphate (PABC)-, phosphoric acid (PHBC)-, potassium dihydrogen phosphate (PKBC)-, and ammonium dihydrogen phosphate (PNBC)-modified biochar were used to investigate P speciation. The Cd immobilization mechanism of biochar was analyzed by XPS and 31P NMR, and the soil quality and the mechanism for the biochar to alleviate Cd stress were also determined. The results demonstrated that PBC (pristine biochar), PABC, PHBC, PKBC, and PNBC reduced the content of soil DTPA-Cd by 14.96 % - 32.19 %, 40.44 % - 47.26 %, 17.52 % - 41.78 %, and 21.90 % - 36.64 %, respectively. The XPS and 31P NMR results demonstrated that the orthophosphate on the surface of PABC, PHBC, PKBC, and PNBC accounted for 82.06 %, 62.77 %, 33.1 %, and 54.46 %, respectively, indicating that PABC has the highest passivation efficiency on soil Cd, which was ascribed to the highest orthophosphate content on the biochar surface. Pot experiments revealed that PABC could reduce the Cd content by 4.18, 4.41, 4.43, 2.94, and 2.57 folds in roots, stems, leaves, pods, and grains, respectively, and at the same time increase the dry and fresh weight of soybean and decrease Cd toxicity to soybean by improving the antioxidant system. In addition, application of the P-modified biochars improved the enzyme activity and physicochemical properties of the soil. This study provides a new perspective for studying the effect of P-modified biochars on soil Cd immobilization.

PHKG2 regulates RSL3-induced ferroptosis in Helicobacter pylori related gastric cancer.

Ferroptosis is a newly discovered form of regulatory cell death induced by iron-dependent lipid peroxidation. Infection with Helicobacter pylori (H. pylori) is regarded as a high-risk factor for the development of gastric cancer (GC) and is associated with an increase in the levels of reactive oxygen species with activation of oncogenic signaling pathways. However, whether GC arising in the context of infection with H. pylori is correlated with ferroptosis is still unknown. In this study, we demonstrate that H. pylori infection increased the sensitivity of GC cells to RSL3 (RAS-selective lethal3)-induced ferroptosis. The molecular subtypes mediated by ferroptosis-related genes are associated with tumor microenvironment (TME) cell infiltration and patient survival. Importantly, we identified that the expression of phosphorylase kinase G2 (PHKG2) was remarkably correlated with H. pylori infection, metabolic biological processes, patient survival and therapy response. We further found the mechanism of H. pylori-induced cell sensitivity to ferroptosis, which involves PHKG2 regulation of the lipoxygenase enzyme Arachidonate 5-Lipoxygenase (ALOX5). In conclusion, PHKG2 facilitates RSL3-induced ferroptosis in H. pylori-positive GC cells by promoting ALOX5 expression. These findings may contribute to a better understanding of the unique pathogenesis of H. pylori-induced GC and allow for maximum efficacy of genetic, cellular, and immune therapies for controlling ferroptosis in diverse contexts.

Mitigation of tobacco bacteria wilt with microbial degradation of phenolic allelochemicals.

Long-term continuous monoculture cropping of tobacco leads to high incidence of tobacco bacterial wilt (TBW) caused by Ralstonia solanacearum, which threatening world tobacco production and causing great economy loss. In this study, a safe and effective way to control TBW by microbial degradation of phenolic allelochemicals (PAs) was explored. Eleven kinds of PAs were identified from continuous tobacco cropping soil. These PAs exhibited various effects on the growth, chemotaxis and biofilm formation of R. solanacearum. Then we isolated eight strains of Bacillus, one strain of Brucella, one strain of Enterobacter and one strain of Stenotrophomonas capable of degrading these PAs. The results of degradation assay showed that these isolated strains could degrade PAs both in culture solutions and soil. Besides, the incidence of TBW caused by R. solanacearum and deteriorated by PAs were significantly decreased by treating with these degrading strains. Furthermore, six out of eleven isolated strains were combined to degrade all the identified PAs and ultimately sharply reduced the incidence of TBW by 61.44% in pot experiment. In addition, the combined degrading bacteria could promote the plant growth and defense response. This study will provide a promising strategy for TBW control in tobacco production.

A Highly Selective Fluorescent Probe for Hypochlorous Acid in Living Cells Based on a Naphthalene Derivative.

Hypochlorous acid (HOCl) was crucial for maintaining the homeostasis in cells and plays vital roles in many physiological and pathological processes. In this work, a highly selective fluorescent probe for hypochlorous acid in living cells was constructed and prepared based on a naphthalene derivative. A naphthalene derivative was utilized as the fluorescent group, and N,N-dimethylthiocarbamate was applied as the selective recognition site for HOCl. Before adding HOCl, the fluorescent probe exhibited weak fluorescence. Upon adding HOCl, the fluorescent probe displayed remarkable fluorescence enhancement. The fluorescence intensity at 502 nm showed a linear response to the concentration of HOCl from 3.0 × 10-7 to 1.0 × 10-5 mol·L-1. The detection limit was estimated to be 1.5 × 10-7 mol·L-1 for HOCl. The fluorescent probe showed fast response and outstanding selectivity toward HOCl. It owned good biocompatibility and had also been successfully applied in the confocal imaging of exogenous and endogenous HOCl in living cells.

Ratiometric Determination of Nitroxyl Utilizing a Novel Fluorescence Resonance Energy Transfer-Based Fluorescent Probe Based on a Coumarin-Rhodol Derivative.

Nitroxyl (HNO) is a member of the reactive nitrogen species, and how to detect it quickly and accurately is a challenging task. In this work, we designed and prepared a fluorescent ratiometric probe based on the fluorescence resonance energy transfer (FRET) mechanism, which can detect HNO with high selectivity. The coumarin derivative was used as an energy donor, the rhodol derivative was applied as an energy receptor, and 2-(diphenylphosphine)benzoate was utilized as the recognition group to detect nitroxyl. In the absence of HNO, the rhodol derivative exists in a non-fluorescent spironolactone state, and the FRET process is inhibited. Upon adding HNO, the closed spironolactone form is transformed into a conjugated xanthene structure and the FRET process occurs. This probe could specifically recognize nitroxyl, showing high sensitivity and selectivity. When the HNO concentration was changed from 3.0 × 10-7 to 2.0 × 10-5 mol·L-1, I 543nm/I 470nm exhibited a satisfactory linear correlation with the concentration of HNO. A detection limit of 7.0 × 10-8 mol·L-1 was obtained. In addition, almost no cell toxicity had been verified for the probe. The probe had been successfully applied to the ratiometric fluorescence imaging of HNO in HepG2 cells.

A novel lysosome-located fluorescent probe for highly selective determination of hydrogen polysulfides based on a naphthalimide derivative.

Hydrogen polysulfides (H2Sn, n > 1) belongs to sulfane sulfur in the reactive sulfur species (RSS) family and plays a significant regulatory role in organisms. Highly selective and lysosome-located probes for detecting hydrogen polysulfides are rare. Thus, it is important to develop a technique to detect the changes of H2Sn level in lysosomes. In this work, a lysosome-targeting fluorescent probe for H2Sn was designed and developed based on a naphthalimide derivative. 4-Hydroxynaphthalimide was selected as the fluorescent group and 2-chloro-5-nitrobenzoate group was used as a specific recognition unit for H2Sn. A morpholine unit was chosen as a lysosome-located group. In the absence of H2Sn, the fluorescent probe exhibited almost no fluorescence. In the presence of H2Sn, the fluorescent probe showed strong fluorescence owing to H2Sn-mediated aromatic substitution-cyclization reactions. The fluorescence emission intensity at 548 nm of the probe showed a good linear relationship toward H2Sn in the range of 2.0 × 10-7 - 9.0 × 10-5 mol·L-1, and the detection limit was found to be 1.5 × 10-7 mol·L-1. The probe possessed a wide work range of pH, including the pH of physiological environment, and high selectivity for H2Sn. There are almost no cytotoxicity and the ability of detecting endogenous and exogenous H2Sn in lysosomes. These results indicate that the fluorescent probe can provide a good tool for intracellular and extracellular detection of H2Sn.

Novel Mitochondria-Targeting and Naphthalimide-based Fluorescent Probe for Detecting HClO in Living Cells.

As a key reactive oxygen species (ROS), hypochlorous acid (HClO) plays an important role in many physiological and pathological processes. The mitochondria-targeting probes for the highly sensitive detection of HClO are desirable. In present work, we designed and synthesized an original mitochondria-localizing and turn-on fluorescent probe for detecting HClO. 4-Aminonaphthalimide was employed as the fluorescent section, the (2-aminoethyl)-thiourea unit was utilized as a typical sensing unit, and the quaternized pyridinium moiety was used as a mitochondria-targeted localization group. When HClO was absent, the probe showed weak fluorescence. In the existence of HClO, the probe revealed a blue fluorescence. Moreover, the turn-on fluorescent probe was able to function in a broad pH scope. There was an excellent linearity between the fluorescence emission intensity at 488 nm and the concentrations of HClO in the range of 5.0 × 10-7 to 2.5 × 10-6 mol·L-1. Additionally, the probe had almost no cell toxicity and possessed an excellent mitochondria-localizing capability. Furthermore, the probe was able to image HClO in mitochondria of living PC-12 cells. The above remarkable properties illustrated that the probe was able to determine HClO in mitochondria of living cells.

A Highly Selective Fluorescent Probe for Hg2+ Based on a 1,8-Naphthalimide Derivative.

Hg2+ has a significant hazardous impact on the environment and ecosystem. There is a great demand for new methods with high selectivity and sensitivity to determine mercury in life systems and environments. In this paper, a novel turn-on Hg2+ fluorescent probe has been reported with a naphthalimide group. The Hg2+ fluorescent probe was designed by the inspiration of the well-known specific Hg2+-triggered thioacetal deprotection reaction. A 1,2-dithioalkyl group was chosen as the specific recognition site of Hg2+. The probe showed weak fluorescence without Hg2+, and the color of the solution was light yellow. In the presence of Hg2+, the probe reacted specifically with the mercury ion to produce an aldehyde and emitted strong fluorescence, and the color of the solution also turned light green, thus realizing the monitoring of the mercury ion. The Hg2+ fluorescent probe showed outstanding sensitivity and selectivity toward Hg2+. Furthermore, the Hg2+ fluorescent probe could work in a wide pH range. The linear relationship between the fluorescence intensity at 510 nm and the concentration of Hg2+ was obtained in a range of Hg2+ concentration from 2.5 × 10-7 to 1.0 × 10-5 M. The detection limit was found to be 4.0 × 10-8 M for Hg2+. Furthermore, with little cell toxicity, the probe was successfully applied to the confocal image of Hg2+ in PC-12 cells.

A FRET-based ratiometric fluorescent probe for highly selective detection of hydrogen polysulfides based on a coumarin-rhodol derivative.

In modern biology, hydrogen polysulfides (H2Sn, n > 1) are members of reactive sulfur species (RSS), with anti-oxidation, cell protection and redox signals in tissues and organs. Therefore, it is crucial to develop a method to monitor the changes of H2Sn level in organisms. We designed and synthesized a ratiometric fluorescent probe for highly selective detection of H2Sn based on the fluorescence resonance energy transfer (FRET) process. In this work, a coumarin derivative was chosen as an energy donor, a rhodol derivative was used as an energy acceptor and a 2-fluoro-5-nitrobenzoate group was applied as a recognition unit for H2Sn. In the absence of H2Sn, the rhodol receptor existed in the non-fluorescent spirolactone state and FRET process was disabled. In the presence of H2Sn, the closed spirolactone form was converted to a conjugated fluorescent xanthenes form to invoke the occurrence of FRET which resulted in a 77 nm red-shift of fluorescence emission from 460 nm to 537 nm. The ratio value of the fluorescence intensity between 537 nm and 460 nm (I537nm/I460nm) of the probe exhibited a good linear relationship toward H2Sn in the range of 3.0 × 10-6-1.0 × 10-4 mol·L-1, and the detection limit was estimated to be 8.0 × 10-7 mol·L-1. In addition, the ratiometric fluorescent probe showed high specificity for H2Sn over other biologically related species. Moreover, the probe displayed little cell toxicity and had been successfully used to the confocal imaging of H2Sn in HepG2 cells by dual emission channels.

A highly selective fluorescent probe for hydrogen polysulfides in living cells based on a naphthalene derivative.

Hydrogen polysulfides (H2Sn, n > 1) are members of reactive sulfur species (RSS) and signaling molecules derived from hydrogen sulfide (H2S). Recently, the functions of H2Sn in physiological and pathological processes have been increasingly recognized. However, their biological effects and detailed mechanisms of action are still little known. Therefore, there is an urgent need to develop highly selective and sensitive techniques for monitoring hydrogen polysulfides (H2Sn) in living cells. In this study, we designed and synthesized a fluorescent probe based on a naphthalene derivative for the detection of hydrogen polysulfides. A naphthalene derivative was applied as the fluorescent main structure and the 2-fluoro-5-nitrobenzoate group was chosen as the recognition unit. In the absence of hydrogen polysulfides, the fluorescent probe displayed almost no fluorescence. In the presence of hydrogen polysulfides, the fluorescent probe exhibited strong fluorescence. The sensing mechanism was based on H2Sn-mediated aromatic substitution-cyclization reactions. The linear range of the response concentration of the probe to hydrogen polysulfide was acquired in a concentration range of H2Sn from 7.5 × 10-7 to 2.5 × 10-5 mol L-1. The detection limit was evaluated to be 5.0 × 10-7 mol L-1 for H2Sn. The fluorescent probe can applied in a wide pH range including physiological condition pH. The fluorescent probe showed high specificity for H2Sn over other reactive sulfur species (RSS). Moreover, the fluorescent probe has been successfully applied to confocal imaging of hydrogen polysulfides in HepG2 cells without cell cytotoxicity. All of such good qualities indicated that it could be used to detect H2Sn in living cells.

Long non-coding RNAs in ocular diseases: new and potential therapeutic targets.

Long non-coding RNAs (lncRNAs) are non-protein coding transcripts containing more than 200 nucleotides. In the past, lncRNAs were considered as 'transcript noise' or 'pseudogenes' and were thus ignored. However, in recent years, lncRNAs have been proven to regulate gene expression at the epigenetic, transcriptional and translational level, and thereby influence cell proliferation, apoptosis, viability, immune response and oxidative stress. Furthermore, increasing evidence points to their involvement in different diseases, including cancer and heart diseases. Recently, lncRNAs were shown to be differentially expressed in ocular tissues and play a significant role in the pathogenesis of ophthalmological disorders such as glaucoma, corneal diseases, cataract, diabetic retinopathy, proliferative vitreoretinopathy and ocular tumors. In this review, we summarize the classification and mechanisms of known lncRNAs, while detailing their biological functions and roles in ocular diseases. Moreover, we provide a concise review of the clinical relevance of lncRNAs as novel, potential therapeutic targets in the treatment of eye diseases.

An in situ hydrogel based on carboxymethyl chitosan and sodium alginate dialdehyde for corneal wound healing after alkali burn.

There is currently no optimal scaffold for the transplantation of limbal stem cells (LSCs) to induce corneal reconstruction after corneal alkali burns. This study attempts to fabricate a novel in situ Alginate-Chitosan hydrogel (ACH) for LSCs transplantation. Sodium alginate dialdehyde (SAD), a biological crosslinker, was prepared by periodate-mediated sodium alginate oxidization. Carboxymethyl chitosan was rapidly crosslinked with SAD via Schiff's base formation between the available aldehyde and amino groups. The ACH is rapidly formed on the wound surface by self-crosslinking without adding any chemical crosslinking component. Gelation time, transmittance, microscopic structure, equilibrium swelling, cytotoxicity, histocompatibility and degradability of the hydrogel were all examined. Rabbit primary LSCs were encapsulated in the hydrogel and transplanted to alkali burn wounds in vivo. Cornea reconstruction was evaluated by visual observation, slit lamp, histological analysis, and immunofluorescence staining. Results showed that the in situ hydrogel was highly transparent, gelated quickly, biocompatible, and had low cytotoxicity. LSCs cultured in vitro expressed the stem marker p63 but lacked the differentiated epithelial markers cytokeratin 3 and 12. Furthermore, the hydrogel encapsulating LSCs could be formed quickly on the alkali burn wound of the cornea and was shown to significantly improve epithelial reconstruction. Taken together, treatment with this novel in situ hydrogel-mediated LSC transplantation system may serve as a rapid and effective method for corneal wound healing. © 2018 The Authors. Journal of Biomedical Materials Research Part A published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 742-754, 2019.

lncRNA XIST promotes gastric cancer progression via regulating miR-337-3p/ HOXC8 axis / 中国肿瘤生物治疗杂志

@# Objective: To investigate the mechanism of lncRNA XIST (XIST) on modulating gastric cancer progression via regulating miR-337-3p/HOXC8 axis. Methods: A total of 58 cases of gastric cancer tissues and corresponding para-cancerous tissues resected from March 2013 to January 2018 in Department of General Surgery, Kailuan General Hospital of Tangshan City were collected for this study; in addition, human gastric cancer cell lines (AGS, MGC803, HGC27) and human gastric mucosal GES-1 cells were also collected. qPCR was used to detect the expressions of XIST and miR-337-3p in above mentioned gastric tissues and cell lines. XIST-knockdown vectors, miR-337-3p mimics, miR-337-3p inhibitor and HOXC8-overexpression vectors were transfected into AGS cells. The proliferation and invasion of AGS cells were detected by CCK-8 and Transwell experiments respectively, and the expression levels of HOXC8, E-cadherin, N-cadherin and vimentin were detected by WB. The targeting relationships between XIST, miR337-3p and HOXC8 were verified by dual-luciferase reporter gene assay. Results: XIST was up-regulated in gastric cancer tissues and cell lines (all P<0.01). XIST knockdown significantly inhibited proliferation, invasion and EMT of AGS cells (P<0.05 or P<0.01). Moreover, XIST directly interacted with miR-337-3p and down-regulated its expression, while HOXC8 was the target gene of miR-3373p. Furthermore, XIST knockdown suppressed proliferation, invasion and EMT ofAGS cells through up-regulating the inhibitory effect of miR-337-3p on HOXC8 (P<0.05 or P<0.01). Conclusion: XIST knockdown can suppress the proliferation, invasion and EMT of AGS cells, which may be related with down-regulation of HOXC8 by targeting miR-337-3p.