The footprint of gut microbiota in gallbladder cancer: a mechanistic review.

Gallbladder cancer (GBC) is the most common malignant tumor of the biliary system with the worst prognosis. Even after radical surgery, the majority of patients with GBC have difficulty achieving a clinical cure. The risk of tumor recurrence remains more than 65%, and the overall 5-year survival rate is less than 5%. The gut microbiota refers to a variety of microorganisms living in the human intestine, including bacteria, viruses and fungi, which profoundly affect the host state of general health, disease and even cancer. Over the past few decades, substantial evidence has supported that gut microbiota plays a critical role in promoting the progression of GBC. In this review, we summarize the functions, molecular mechanisms and recent advances of the intestinal microbiota in GBC. We focus on the driving role of bacteria in pivotal pathways, such as virulence factors, metabolites derived from intestinal bacteria, chronic inflammatory responses and ecological niche remodeling. Additionally, we emphasize the high level of correlation between viruses and fungi, especially EBV and Candida spp., with GBC. In general, this review not only provides a solid theoretical basis for the close relationship between gut microbiota and GBC but also highlights more potential research directions for further research in the future.

Acylcarnitines promote gallbladder cancer metastasis through lncBCL2L11-THOC5-JNK axis.

BACKGROUND: The progression of gallbladder cancer (GBC) is accompanied by abnormal fatty acid ß-oxidation (FAO) metabolism. Different types of lipids perform various biological functions. This study aimed to determine the role of acyl carnitines in the molecular mechanisms of GBC progression. METHODS: Distribution of lipids in GBC was described by LC-MS-based lipidomics. Cellular localization, expression level and full-length of lncBCL2L11 were detected using fluorescence in situ hybridization (FISH) assays, subcellular fractionation assay and 5' and 3' rapid amplification of the cDNA ends (RACE), respectively. In vitro and in vivo experiments were used to verify the biological function of lncBCL2L11 in GBC cells. Methylated RNA Immunoprecipitation (MeRIP) was performed to detect the methylation levels of lncBCL2L11. RNA pull-down assay and RNA immunoprecipitation (RIP) assay were used to identify lncBCL2L11 interacting proteins. Co-Immunoprecipitation (Co-IP) and Western blot assay were performed to validate the regulatory mechanism of lncBCL2L11 and THO complex. RESULTS: Acylcarnitines were significantly up-regulated in GBC tissues. High serum triglycerides correlated to decreased survival in GBC patients and promoted tumor migration. LncBCL2L11 was identified in the joint analysis of highly metastatic cells and RNA sequencing data. LncBCl2L11 prevented the binding of THOC6 and THOC5 and causes the degradation of THOC5, thus promoting the accumulation of acylcarnitines in GBC cells, leading to the malignant progression of cancer cells. In addition, highly expressed acylcarnitines stabilized the expression of lncBCL2L11 through N6-methyladenosine methylation (m6A), forming a positive feedback regulation in tumor dissemination. CONCLUSIONS: LncBCL2L11 is involved in gallbladder cancer metastasis through FAO metabolism. High lipid intake is associated with poor prognosis of GBC. Therefore, targeting lncBCL2L11 and its pathway-related proteins or reducing lipid intake may be significant for the treatment of GBC patients.

The anticancer activity of bile acids in drug discovery and development.

Bile acids (BAs) constitute essential components of cholesterol metabolites that are synthesized in the liver, stored in the gallbladder, and excreted into the intestine through the biliary system. They play a crucial role in nutrient absorption, lipid and glucose regulation, and the maintenance of metabolic homeostasis. In additional, BAs have demonstrated the ability to attenuate disease progression such as diabetes, metabolic disorders, heart disease, and respiratory ailments. Intriguingly, recent research has offered exciting evidence to unveil their potential antitumor properties against various cancer cell types including tamoxifen-resistant breast cancer, oral squamous cell carcinoma, cholangiocarcinoma, gastric cancer, colon cancer, hepatocellular carcinoma, prostate cancer, gallbladder cancer, neuroblastoma, and others. Up to date, multiple laboratories have synthesized novel BA derivatives to develop potential drug candidates. These derivatives have exhibited the capacity to induce cell death in individual cancer cell types and display promising anti-tumor activities. This review extensively elucidates the anticancer activity of natural BAs and synthetic derivatives in cancer cells, their associated signaling pathways, and therapeutic strategies. Understanding of BAs and their derivatives activities and action mechanisms will evidently assist anticancer drug discovery and devise novel treatment.

SNHG15 promotes gallbladder cancer progression by enhancing the autophagy of tumor cell under nutrition stress.

Gallbladder cancer (GBC) is a major malignant carcinoma of the biliary tract with extremely poor prognosis. Currently, there is no useful therapy strategies for GBC treatment, indicating the unmet mechanism researches for GBC. In this study, our data showed that SNHG15 expression significantly up-regulated and its high expression associated with poor overall survival of patients suffer from GBC. Functional experiments showed that SNHG15 depletion delayed the proliferation and enhanced the apoptosis of GBC tumor cells under the nutrition stress condition, which further confirmed in the subcutaneous xenograft model and liver metastasis model. Mechanistically, SNHG15 could interact with AMPK and facilitate the phosphorylation of AMPK to Tuberous sclerosis complex TSC2, resulting in mTOR suppression and autophagy enhancement, and finally, conferring the GBC cell sustain proliferation under nutrition stress. Taken together, our findings revealed that SNHG15 promotes GBC tumor progression by enhancing the autophagy under poor nutrition tumor microenvironment, which could be a promising targets for GBC.

Bacillus velezensis SQR9 inhibition to fungal denitrification responsible for decreased N2O emissions from acidic soils.

Tropical and subtropical acidic soils are hotspots of global terrestrial nitrous oxide (N2O) emissions, with N2O produced primarily through denitrification. Plant growth-promoting microbes (PGPMs) may effectively mitigate soil N2O emissions from acidic soils, achieved through differential responses of bacterial and fungal denitrification to PGPMs. To test this hypothesis, we conducted a pot experiment and the associated laboratory trials to gain the underlying insights into the PGPM Bacillus velezensis strain SQR9 effects on N2O emissions from acidic soils. SQR9 inoculation significantly reduced soil N2O emissions by 22.6-33.5 %, dependent on inoculation dose, and increased the bacterial AOB, nirK and nosZ genes abundance, facilitating the reduction of N2O to N2 in denitrification. The relative contribution of fungi to the soil denitrification rate was 58.4-77.1 %, suggesting that the N2O emissions derived mainly from fungal denitrification. The SQR9 inoculation significantly inhibited the fungal denitrification and down-regulated fungal nirK gene transcript, dependent on the SQR9 sfp gene, which was necessary for secondary metabolite synthesis. Therefore, our study provides new evidence that decreased N2O emissions from acidic soils can be due to fungal denitrification inhibited by PGPM SQR9 inoculation.

Effects of optical and radar satellite observations within Google Earth Engine on soil organic carbon prediction models in Spain.

The modeling and mapping of soil organic carbon (SOC) has advanced through the rapid growth of Earth observation data (e.g., Sentinel) collection and the advent of appropriate tools such as the Google Earth Engine (GEE). However, the effects of differing optical and radar sensors on SOC prediction models remain uncertain. This research aims to investigate the effects of different optical and radar sensors (Sentinel-1/2/3 and ALOS-2) on SOC prediction models based on long-term satellite observations on the GEE platform. We also evaluate the relative impact of four synthetic aperture radar (SAR) acquisition configurations (polarization mode, band frequency, orbital direction and time window) on SOC mapping with multiband SAR data from Spain. Twelve experiments involving different satellite data configurations, combined with 4027 soil samples, were used for building SOC random forest regression models. The results show that the synthesis mode and choice of satellite images, as well as the SAR acquisition configurations, influenced the model accuracy to varying degrees. Models based on SAR data involving cross-polarization, multiple time periods and "ASCENDING" orbits outperformed those involving copolarization, a single time period and "DESCENDING" orbits. Moreover, combining information from different orbital directions and polarization modes improved the soil prediction models. Among the SOC models based on long-term satellite observations, the Sentinel-3-based models (R2 = 0.40) performed the best, while the ALOS-2-based model performed the worst. In addition, the predictive performance of MSI/Sentinel-2 (R2 = 0.35) was comparable with that of SAR/Sentinel-1 (R2 = 0.35); however, the combination (R2 = 0.39) of the two improved the model performance. All the predicted maps involving Sentinel satellites had similar spatial patterns that were higher in northwest Spain and lower in the south. Overall, this study provides insights into the effects of different optical and radar sensors and radar system parameters on soil prediction models and improves our understanding of the potential of Sentinels in developing soil carbon mapping.

YKL-40 derived from infiltrating macrophages cooperates with GDF15 to establish an immune suppressive microenvironment in gallbladder cancer.

Despite of the high lethality of gallbladder cancer (GBC), little is known regarding molecular regulation of the tumor immunosuppressive microenvironment. Here, we determined tumor expression levels of YKL-40 and the molecular mechanisms by which YKL-40 regulates escape of anti-tumor immune surveillance. We found that elevated expression levels of YKL-40 in plasma and tissue were correlated with tumor size, stage IV and lymph node metastasis. Single cell transcriptome analysis revealed that YKL-40 was predominantly derived from M2-like subtype of infiltrating macrophages. Blockade of M2-like macrophage differentiation of THP-1 cells with YKL-40 shRNA resulted in reprogramming to M1-like macrophages and restricting tumor development. YKL-40 induced tumor cell expression and secretion of growth differentiation factor 15 (GDF15), thus coordinating to promote PD-L1 expression mediated by PI3K, AKT and/or Erk activation. Interestingly, extracellular GDF15 inhibited intracellular expression of GDF15 that suppressed PD-L1 expression. Thus, YKL-40 disrupted the balance of pro- and anti-PD-L1 regulation to enhance expression of PD-L1 and inhibition of T cell cytotoxicity, leading to tumor immune evasion. The data suggest that YKL-40 and GDF15 could serve as diagnostic biomarkers and immunotherapeutic targets for GBC.

Nicotinamide N -methyltransferase promotes M2 macrophage polarization by IL6 and MDSC conversion by GM-CSF in gallbladder carcinoma.

BACKGROUND AND AIMS: Nicotinamide N -methyltransferase (NNMT), an enzyme responsible for the methylation of nicotinamide, is involved in many metabolic pathways in adipose tissue and the liver. However, the role of NNMT in editing the tumor immune microenvironment is not well understood. APPROACH AND RESULTS: Here, we identified that NNMT can promote IL6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) expression by decreasing the tri-methyl-histone H3 levels on the promoters of IL6 and CSF2 (encoding GM-CSF) and CCAAT/Enhancer Binding Protein, an essential transcription factor for IL6 expression, thus promoting differentiation of macrophages into M2 type tumor-associated macrophages and generation of myeloid-derived suppressor cells from peripheral blood mononuclear cells. Treatment of xenografted tumor models overexpressing NNMT gallbladder carcinoma (GBC) cells with the NNMT inhibitor JBSNF-000088 resulted in compromised tumor development and decreased expression levels of IL6, GM-CSF, tumor-associated macrophage marker CD206, and myeloid-derived suppressor cell marker CD33 but increased expression levels of CD8. In addition, elevated expression of NNMT in tumors of patients with GBC was correlated with increased expression levels of CD206 and CD33 but with decreased levels of CD8 and survival of patients. CONCLUSIONS: These data highlight the critical role of NNMT in GBC progression. Inhibition of NNMT by JBSNF-000088 is a potential molecular target for GBC immunotherapy.

Complete Tolerogenic Adjuvant Stimulates Regulatory T Cell Response to Immunization.

We have determined in mice the minimum composition required for forming a vaccine adjuvant that stimulates a regulatory T (Treg) cell response to immunization, and we named the adjuvant "complete tolerogenic adjuvant." This new kind of adjuvant may let us use the well-proven "Ag with adjuvant" form of immunization for inducing Treg cell-mediated Ag-specific immunosuppression. The minimum composition consists of dexamethasone, rapamycin, and monophosphoryl lipid A at a mass ratio of 8:20:3. By dissecting the respective role of each of these components during immunization, we have further shown why immunosuppressive and immunogenic agents are both needed for forming true adjuvants for Treg cells. This finding may guide the design of additional, and potentially more potent, complete tolerogenic adjuvants with which we may form numerous novel vaccines for treating immune diseases.

Long-term exposure to genistein inhibits the proliferation of gallbladder cancer by downregulating the MCM complex.

Soy isoflavones are natural tyrosine kinase inhibitors closely associated with decreased morbidity and mortality of various tumors. The activation of tyrosine kinases such as ERBB2 is the mechanism by which cholecystitis transforms into gallbladder cancer (GBC), therefore, it is important to investigate the relationship between long-term exposure to soy isoflavones and the occurrence and progression of GBC. This case-control study (n = 85 pairs) found that the high level of plasma soy isoflavone-genistein (GEN) was associated with a lower risk of gallbladder cancer (≥326.00 ng/mL compared to ≤19.30 ng/mL, crude odds ratio 0.15, 95% CI 0.04-0.59; P for trend = 0.016), and that the level of GEN exposure negatively correlated with Ki67 expression in GBC tissue (n = 85). Consistent with these results, the proliferation of GBC cells was inhibited in the long-term exposure models of GEN in vitro and in vivo. The long-term exposure to GEN reduced the tyrosine kinase activity of ERBB2 and impaired the function of the PTK6-AKT-GSK3ß axis, leading to downregulation of the MCM complex in GBC cells. In summary, long-term exposure to GEN associated with soy products intake might play a certain role in preventing GBC and even inhibiting the proliferation of GBC cells.

tRF-3013b inhibits gallbladder cancer proliferation by targeting TPRG1L.

BACKGROUND: tRNA-derived fragments (tRFs) are newly discovered noncoding RNAs and regulate tumor progression via diverse molecular mechanisms. However, the expression and biofunction of tRFs in gallbladder cancer (GBC) have not been reported yet. METHODS: The expression of tRFs in GBC was detected by tRF and tiRNA sequencing in GBC tissues and adjacent tissues. The biological function of tRFs was investigated by cell proliferation assay, clonal formation assay, cell cycle assay, and xenotransplantation model in GBC cell lines. The molecular mechanism was discovered and verified by transcriptome sequencing, fluorescence in situ hybridization (FISH), target gene site prediction, and RNA binding protein immunoprecipitation (RIP). RESULTS: tRF-3013b was significantly downregulated in GBC compared with para-cancer tissues. Decreased expression of tRF-3013b in GBC patients was correlated with poor overall survival. Dicer regulated the production of tRF-3013b, and its expression was positively correlated with tRF-3013b in GBC tissues. Functional experiments demonstrated that tRF-3013b inhibited GBC cell proliferation and induced cell-cycle arrest. Mechanically, tRF-3013b exerted RNA silencing effect on TPRG1L by binding to AGO3, and then inhibited NF-κB. TPRG1L overexpression could rescue the effects of tRF-3013b on GBC cell proliferation. CONCLUSIONS: This study indicated that Dicer-induced tRF-3013b inhibited GBC proliferation by targeting TPRG1L and repressed NF-κB, pointing to tRF-3013b as a novel potential therapeutic target of GBC.

Fibrinogen promotes gallbladder cancer cell metastasis and extravasation by inducing ICAM1 expression.

Fibrinogen plays an important role in tumor progression. Here, we explored the role of fibrinogen in gallbladder cancer (GBC) metastasis. The plasma fibrinogen level in M1 GBC patients was higher than in M0 GBC patients, indicating that fibrinogen may participate in GBC metastasis. Treatment of GBC cell lines with fibrinogen promoted metastasis and induced the expression of intercellular adhesion molecule 1 (ICAM1). ICAM1 overexpression promoted metastasis and knockdown inhibited it. The cell adhesion and transendothelial migration of GBC cells were enhanced by fibrinogen treatment and ICAM1 overexpression. In addition, the medium of fibrinogen-treated and overexpression-ICAM1 NOZ cells exhibited enhanced macrophages recruitment. This may work in concert to promote angiogenesis. Immunohistochemistry results on clinical specimens showed that higher fibrinogen levels, higher ICAM1 expression, higher blood vessel density, and higher macrophage levels were present simultaneously. Collectively, this study indicates fibrinogen promotes metastasis and extravasation by inducing ICAM1 expression to enhance tumor cell migration, cell adhesion, transendothelial migration and promote angiogenesis and increase vascular endothelial permeability.

Novel protein kinase inhibitor TT-00420 inhibits gallbladder cancer by inhibiting JNK/JUN-mediated signaling pathway.

PURPOSE: This study aimed to investigate the efficiency of our chemically synthesized TT-00420, a novel spectrum-selective multiple protein kinase inhibitor, in cultured cells and animal models of gallbladder cancer (GBC) and explore its potential mechanism. METHODS: Multiple GBC models were established to assess the anti-tumor efficiency, toxicity, and pharmacokinetics of TT-00420. Integrated transcriptomic, proteomic and phosphoproteomic analysis was conducted to identify potential downstream effectors of TT-00420. Western blotting, qRT-PCR, nuclear-cytoplasm separation, and immunofluorescence were performed to confirm the multi-omic results and explore the molecular mechanism of TT-00420. Immunohistochemistry was used to detect FGFR1 and p-FGFR1 expression levels in GBC samples. Autodock software was utilized to investigate the potential binding mode between the TT-00420 and the human FGFR1. RESULTS: We found that TT-00420 exerted potent growth inhibition of GBC cell lines and multiple xenograft models. Treatment of mice with 15 mg/kg TT-00420 via gavage displayed a half-life of 1.8 h in the blood and rapid distribution to the liver, kidneys, lungs, spleen, and tumors at 0.25 h, but no toxicity to these organs over 2 weeks. Multi-omic analysis revealed c-Jun as a potential downstream effector after TT-00420 treatment. Mechanistically, TT-00420 showed rigorous ability to block FGFR1 and its downstream JNK-JUN (S63/S73) signaling pathway, and induce c-Jun S243-dependent MEK/ERK reactivation, leading to FASLG-dependent tumor cell death. Finally, we found that FGFR1 and p-FGFR1 expression was elevated in GBC patients and these levels correlated with decreased patient survival. CONCLUSIONS: TT-00420 shows potent antitumor efficacy and may serve as a novel agent to improve GBC prognosis.

Development and Validation of a Prognostic Nomogram Based on the Systemic Immune-Inflammation Index for Resectable Gallbladder Cancer to Predict Survival and Chemotherapy Benefit.

OBJECTIVES: To investigate the prognostic significance of the systemic immune-inflammation index (SII) in patients after radical cholecystectomy for gallbladder cancer (GBC) using overall survival (OS) as the primary outcome measure. METHODS: Based on data from a multi-institutional registry of patients with GBC, significant prognostic factors after radical cholecystectomy were identified by multivariate Cox proportional hazards model. A novel staging system was established, visualized as a nomogram. The response to adjuvant chemotherapy was compared between patients in different subgroups according to the novel staging system. RESULTS: Of the 1072 GBC patients enrolled, 691 was randomly selected in the discovery cohort and 381 in the validation cohort. SII>510 was found to be an independent predictor of OS (hazard ratio [HR] 1.90, 95% confidence interval [CI] 1.42-2.54). Carbohydrate antigen 199(CA19-9), tumor differentiation, T stage, N stage, margin status and SII were involved in the nomogram. The nomogram showed a superior prediction compared with models without SII (1-, 3-, 5-year integrated discrimination improvement (IDI):2.4%, 4.1%, 5.4%, P<0.001), and compared to TNM staging system (1-, 3-, 5-year integrated discrimination improvement (IDI):5.9%, 10.4%, 12.2%, P<0.001). The C-index of the nomogram in predicting OS was 0.735 (95% CI 0.683-0.766). The novel staging system based on the nomogram showed good discriminative ability for patients with T2 or T3 staging and with negative lymph nodes after R0 resection. Adjuvant chemotherapy offered significant survival benefits to these patients with poor prognosis. CONCLUSIONS: SII was an independent predictor of OS in patients after radical cholecystectomy for GBC. The new staging system identified subgroups of patients with T2 or T3 GBC with negative lymph nodes who benefited from adjuvant chemotherapy. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, identifier (NCT04140552).

Protocol for a gallbladder cancer registry study in China: the Chinese Research Group of Gallbladder Cancer (CRGGC) study.

INTRODUCTION: Gallbladder cancer (GBC), the sixth most common gastrointestinal tract cancer, poses a significant disease burden in China. However, no national representative data are available on the clinical characteristics, treatment and prognosis of GBC in the Chinese population. METHODS AND ANALYSIS: The Chinese Research Group of Gallbladder Cancer (CRGGC) study is a multicentre retrospective registry cohort study. Clinically diagnosed patient with GBC will be identified from 1 January 2008 to December, 2019, by reviewing the electronic medical records from 76 tertiary and secondary hospitals across 28 provinces in China. Patients with pathological and radiological diagnoses of malignancy, including cancer in situ, from the gallbladder and cystic duct are eligible, according to the National Comprehensive Cancer Network 2019 guidelines. Patients will be excluded if GBC is the secondary diagnosis in the discharge summary. The demographic characteristics, medical history, physical examination results, surgery information, pathological data, laboratory examination results and radiology reports will be collected in a standardised case report form. By May 2021, approximately 6000 patient with GBC will be included. The clinical follow-up data will be updated until 5 years after the last admission for GBC of each patient. The study aimed (1) to depict the clinical characteristics, including demographics, pathology, treatment and prognosis of patient with GBC in China; (2) to evaluate the adherence to clinical guidelines of GBC and (3) to improve clinical practice for diagnosing and treating GBC and provide references for policy-makers. ETHICS AND DISSEMINATION: The protocol of the CRGGC has been approved by the Committee for Ethics of Xinhua Hospital, Shanghai Jiao Tong University School of Medicine (SHEC-C-2019-085). All results of this study will be published in peer-reviewed journals and presented at relevant conferences. TRIAL REGISTRATION NUMBER: NCT04140552, Pre-results.

Prediction of soil organic carbon and the C:N ratio on a national scale using machine learning and satellite data: A comparison between Sentinel-2, Sentinel-3 and Landsat-8 images.

Soil organic carbon (SOC) and soil carbon-to-nitrogen ratio (C:N) are the main indicators of soil quality and health and play an important role in maintaining soil quality. Together with Landsat, the improved spatial and temporal resolution Sentinel sensors provide the potential to investigate soil information on various scales. We analyzed and compared the potential of satellite sensors (Landsat-8, Sentinel-2 and Sentinel-3) with various spatial and temporal resolutions to predict SOC content and C:N ratio in Switzerland. Modeling was carried out at four spatial resolutions (800 m, 400 m, 100 m and 20 m) using three machine learning techniques: support vector machine (SVM), boosted regression tree (BRT) and random forest (RF). Soil prediction models were generated in these three machine learners in which 150 soil samples and different combinations of environmental data (topography, climate and satellite imagery) were used as inputs. The prediction results were evaluated by cross-validation. Our results revealed that the model type, modeling resolution and sensor selection greatly influenced outputs. By comparing satellite-based SOC models, the models built by Landsat-8 and Sentinel-2 performed the best and the worst, respectively. C:N ratio prediction models based on Landsat-8 and Sentinel-2 showed better results than Sentinel-3. However, the prediction models built by Sentinel-3 had competitive or better accuracy at coarse resolutions. The BRT models constructed by all available predictors at a resolution of 100 m obtained the best prediction accuracy of SOC content and C:N ratio; their relative improvements (in terms of R2) compared to models without remote sensing data input were 29.1% and 58.4%, respectively. The results of variable importance revealed that remote sensing variables were the best predictors for our soil prediction models. The predicted maps indicated that the higher SOC content was mainly distributed in the Alps, while the C:N ratio shared a similar distribution pattern with land use and had higher values in forest areas. This study provides useful indicators for a more effective modeling of soil properties on various scales based on satellite imagery.

HMGB1-Neutralizing IgM Antibody Is a Normal Component of Blood Plasma.

Extracellular high-mobility group box 1 (HMGB1) is a prototypic damage-associated molecular pattern. Although a homeostatic level of extracellular HMGB1 may be beneficial for immune defense, tissue repair, and tissue regeneration, excessive HMGB1 is linked to inflammatory diseases. This prompts an intriguing question: how does a healthy body control the level of extracellular HMGB1? In this study, in the plasma of both healthy humans and healthy mice, we have identified an anti-HMGB1 IgM autoantibody that neutralizes extracellular HMGB1 via binding specifically to a 100% conserved epitope, namely HMW4 (HMGB198-112). In mice, this anti-HMW4 IgM is produced by peritoneal B-1 cells, and concomitant triggering of their BCR and TLR4 by extracellular HMGB1 stimulates the production of anti-HMW4 IgM. The ability of extracellular HMGB1 to induce its own neutralizing Ab suggests a feedback loop limiting the level of this damage-associated molecular pattern in a healthy body.

High-resolution digital mapping of soil organic carbon and soil total nitrogen using DEM derivatives, Sentinel-1 and Sentinel-2 data based on machine learning algorithms.

Soil organic carbon (SOC) and soil total nitrogen (STN) are important indicators of soil health and play a key role in the global carbon and nitrogen cycles. High-resolution radar Sentinel-1 and multispectral Sentinel-2 images have the potential to investigate soil spatial distribution information over a large area, although Sentinel-1 and Sentinel-2 data have rarely been combined to map either SOC or STN content. In this study, we applied machine learning techniques to map both SOC and STN content in the southern part of Central Europe using digital elevation model (DEM) derivatives, multi-temporal Sentinel-1 and Sentinel-2 data, and evaluated the potential of different remote sensing sensors (Sentinel-1 and Sentinel-2) to predict SOC and STN content. Four machine-learners including random forest (RF), boosted regression trees (BRT), support vector machine (SVM) and Bagged CART were used to construct predictive models of SOC and STN contents based on 179 soil samples and different combinations of environmental covariates. The performance of these models was evaluated based on a 10-fold cross-validation method by three statistical indicators. Overall, the BRT model performed better than RF, SVM and Bagged CART, and these models yielded similar spatial distribution patterns of SOC and STN. Our results showed that multi-source sensor methods provided more accurate predictions of SOC and STN contents than individual sensors. The application of radar Sentinel-1 and multispectral Sentinel-2 images proved useful for predicting SOC and STN. A combination of Sentinel-1/2-derived predictors and DEM derivatives yielded the highest prediction accuracy. The prediction accuracy changed with and without the Sentinel-1/2-derived predictors, with the R2 for estimating both SOC and STN content using the BRT model increasing by 12.8% and 18.8%, respectively. Topographic variables were the main explanatory variables for SOC and STN predictions, where elevation was assigned as the variable with the most importance by the models. The results of this study illustrate the potential of free high-resolution radar Sentinel-1 and multispectral Sentinel-2 data as input when developing SOC and STN prediction models.

Erratum to "Platelet-Rich Fibrin Promotes Periodontal Regeneration and Enhances Alveolar Bone Augmentation".

[This corrects the article DOI: 10.1155/2013/638043.].

Calcium Superphosphate-Mediated Reshaping of Denitrifying Bacteria Community Contributed to N2O Mitigation in Pig Manure Windrow Composting.

Composting is recognized as an effective strategy for the sustainable use of organic wastes, but also as an important emission source of nitrous oxide (N2O) contributing to global warming. The effects of calcium superphosphate (CaSSP) on N2O production during composting are reported to be controversial, and the intrinsic microbial mechanism remains unclear. Here, a pig manure windrow composting experiment lasting for ~60 days was performed to evaluate the effects of CaSSP amendment (5%, w/w) on N2O fluxes in situ, and to determine the denitrifiers' response, and their driving factors. Results indicated that CaSSP amendment significantly reduced N2O emissions as compared to the control pile (maximum N2O emission rate reduced by 64.5% and total emission decreased by 49.8%). CaSSP amendment reduced the abundance of nirK gene encoding for nitrite reductase, while the abundance of nosZ gene (N2O reductase) was enriched. Finally, we built a schematic model and indicated that the abundance of nirK gene was likely to play a key role in mediating N2O production, which were correlated with NH4+-N and NO3--N changing responsive to CaSSP. Our finding implicates that CaSSP application could be a potential strategy for N2O mitigation in manure windrow composting, and the revealed microbial mechanism is helpful for deepening the understanding of the interaction among N-cycle functional genes, physicochemical factors, and greenhouse gases (GHG) emissions.