Atmospheric nourishment of global ocean ecosystems

Over the vast open ocean, vital nutrients for phytoplankton growth in the sunlit surface layer are largely provided through physical transport from deep waters, but some nutrients are also provided through atmospheric deposition of desert dust. The extent and magnitude of dust-mediated effects on surface ocean ecosystems have been difficult to estimate globally. In this work, we use global satellite ocean color products to demonstrate widespread responses to atmospheric dust deposition across a diverse continuum of phytoplankton nutritional conditions. The observed responses vary regionally, with some areas exhibiting substantial changes in phytoplankton biomass, whereas in other areas, the response reflects a change in physiological status or health. Climate-driven changes in atmospheric aerosols will alter the relative importance of this nutrient source.

An XGBoost Algorithm Based on Molecular Structure and Molecular Specificity Parameters for Predicting Gas Adsorption

In this paper, an improved Extreme Gradient Boosting (XGBoost) algorithm based on the Graph Isomorphic Network (GIN) for predicting the adsorption performance of metal-organic frameworks (MOFs) is developed. It is shown that the graph isomorphic layer of this algorithm can directly learn the feature representation of materials from the connection of atoms in MOFs. Then, XGBoost can be used to predict the adsorption performance of MOFs based on feature representation. In this sense, it is not only possible to achieve end-to-end prediction directly from the structure of MOFs to adsorption performance but also to ensure the accuracy of prediction. The comparison between Grand Canonical Monte Carlo (GCMC) simulation and prediction supports the performance and effectiveness of the proposed algorithm.

The Efficacy of At-home, In-office, and Combined Bleaching Regimens: A Randomized Controlled Clinical Trial

OBJECTIVE

The aim of this study was to compare the clinical efficacy of at-home, in-office, and combined bleaching regimens.

METHODS

Forty-eight participants were recruited and randomly divided into four groups based on the bleaching regimen (n=12) as follows: 1) at-home bleaching using 10% carbamide peroxide (Opalescence PF 10%, Ultradent) for 14 days (HB); 2) two sessions of in-office bleaching using 40% hydrogen peroxide (Opalescence BOOST PF 40%, Ultradent) with a one-week interval (OB); 3) one session of in-office bleaching followed by at-home bleaching for seven days (OHB); and 4) at-home bleaching for seven days followed by one session of in-office bleaching (HOB). Tooth color was measured using a spectrophotometer (Easyshade, Vita ZahnFabrik) at baseline (T0), day 8 (T1), day 15 (T2), and day 43 (T3, four weeks after the end of the bleaching treatment). The color data were calculated using the CIEDE2000 (ΔE00) and whiteness index for dentistry (WID) formulas. Tooth sensitivity (TS) was recorded using a visual analogue scale (VAS) for 16 days. Data were analyzed by one-way analysis of variance (ANOVA) and the Wilcoxon signed-rank test (α=0.05).

RESULTS

All bleaching regimens resulted in a significant increase in WID values (all p<0.05), while no significant differences in WID and ΔWID values were found among the different groups at each time point (all p>0.05). Significant differences in ΔE00 values were observed between T1 and T3 for all groups (all p<0.05), while no significant differences in ΔE00 values were found among the different groups at any time point (all p>0.05). Significantly lower TS values were observed in the HB group than in the OB and HOB groups (p=0.006 and p=0.001, respectively).

CONCLUSIONS

All bleaching regimens resulted in great color improvement, and different regimens led to similar color changes at any of the evaluation time points. The sequence of treatments applying in-office bleaching or at-home bleaching did not affect the bleaching efficacy. The in-office bleaching and combined bleaching regimens yielded a higher intensity of TS than did at-home bleaching.

[NKD1 promotes glucose uptake in colon cancer cells by activating YWHAE transcription]

OBJECTIVE

Bo investigate the regulatory relationship between NKD1 and YWHAE and the mechanism of NKD1 for promoting tumor cell proliferation.

METHODS

HCT116 cells transfected with pcDNA3.0-NKD1 plasmid, SW620 cells transfected with NKD1 siRNA, HCT116 cells with stable NKD1 overexpression (HCT116-NKD1 cells), SW620 cells with nkd1knockout (SW620-nkd1^-/- cells), and SW620-nkd1^-/- cells transfected with pcDNA3.0-YWHAE plasmid were examined for changes in mRNA and protein expression levels of YWHAE using qRT-PCR and Western blotting. Chromatin immunoprecipitation (ChIP) assay was used to detect the binding of NKD1 to the promoter region of YWHAE gene. The regulatory effect of NKD1 on YWHAE gene promoter activity was analyzed by dual-luciferase reporter gene assay, and the interaction between NKD1 and YWHAE was analyzed with immunofluorescence assay. The regulatory effect of NKD1 on glucose uptake was examined in the tumor cells.

RESULTS

In HCT116 cells, overexpression of NKD1 significantly enhanced the expression of YWHAE at both the mRNA and protein levels, while NKD1 knockout decreased its expression in SW620 cells (P < 0.001). ChIP assay showed that NKD1 protein was capable of binding to the YWHAE promoter sequence; dual luciferase reporter gene assay showed that NKD1 overexpression (or knockdown) in the colon cancer cells significantly enhanced (or reduced) the transcriptional activity of YWHAE promoter (P < 0.05). Immunofluorescence assay demonstrated the binding of NKD1 and YWHAE proteins in colon cancer cells. NKD1 knockout significantly reduced glucose uptake in colon cancer cells (P < 0.01), while YWHAE overexpression restored the glucose uptake in NKD1-knockout cells (P < 0.05).

CONCLUSION

NKD1 protein activates the transcriptional activity of YWHAE gene to promote glucose uptake in colon cancer cells.

[Drug resistance and genomic characteristics of Salmonella enterica serovar London from clinical and food sources in Hangzhou City from 2017 to 2021]

Objective: To analyze the drug resistance and genomic characteristics of Salmonella enterica serovar London isolated from clinical and food sources in Hangzhou City from 2017 to 2021. Methods: A total of 91 Salmonella enterica serovar London strains isolated from Hangzhou City from 2017 to 2021 were analyzed for drug susceptibility, pulsed field gel electrophoresis (PFGE) typing and whole genome sequencing. Multilocus sequence typing (MLST), core genome multilocus sequence typing (cgMLST) and detection of drug resistance genes were performed by using the sequencing data. Phylogenetic analysis was conducted to compare the 91 genomes from Hangzhou City with 347 genomes from public databases. Results: No significant difference in the drug resistance rate was observed between clinical strains and food strains to 18 drugs in Hangzhou City(all P>0.05), and the multidrug resistance (MDR) rate was 75.8% (69/91). Most strains were resistant to 7 drug classes simultaneously. One strain was resistant to Polymyxin E as well as positive for mcr-1.1, and 50.5% (46/91) of the strains were resistant to Azithromycin and were positive for mph(A). All 91 Salmonella enterica serovar London strains were ST155, which were subdivided into 44 molecular types by PFGE and 82 types by cgMLST. Phylogenetic analysis showed that most strains from Hangzhou City (83/91) were clustered together, and a small number of human isolates from Europe, North America and pork isolates from Hubei and Shenzhen were mixed in the cluster. Other strains from Hangzhou City (8/91) were closely related to strains from Europe, America and Southeast Asia. Strains isolated from pork were the most closely related to clinical strains. Conclusion: The epidemic of Salmonella enterica serovar London in Hangzhou City is mainly caused by the spread of ST155 strains, which is mainly transmitted locally. At the same time, cross-region transmission to Europe, North America, Southeast Asia, and other provinces and cities in China may also occur. There is no significant difference in the drug resistance rate between clinical strains and food strains, and a high level of MDR is found in the strains. Clinical infection of Salmonella enterica serovar London may be closely related to pork consumption in Hangzhou City.

Syndecan-3 Coregulates Milk Fat Metabolism and Inflammatory Reactions in Bovine Mammary Epithelial Cells through AMPK/SIRT1 Signaling Pathway

Transcriptome sequencing showed that syndecan-3 (SDC3) was differentially expressed in high-fat and low-fat mammary epithelial cells of Chinese Holstein cows. Previous studies found that SDC3 plays an important role in inflammatory diseases and virus infection. However, those studies did not confirm whether or not the functional gene SDC3, which plays an important role in regulating milk fat metabolism, has an effect on susceptibility to breast tissue diseases. Therefore, we studied the effects of SDC3 on milk lipid metabolism and inflammation in bovine mammary epithelial cells (BMECs) and further explored the common regulatory pathway of SDC3 in both. The overexpression of SDC3 increased the contents of triglycerides and cholesterol, reduced the content of non-esterified fatty acids, inhibited the expression of inflammatory factors (IL-6, IL-1β, TNF-α and COX-2), and reduced the production of ROS in BMECs. However, silenced SDC3 had the opposite effect. Further exploring the mechanisms of SDC3, we found that SDC3 upregulated the expression of peroxisome proliferator-activated receptor gamma (PPARG) through the AMPK/SIRT1 signal pathway to promote milk fat synthesis. It also regulated the activation of the NF-κB pathway through the AMPK/SIRT1 signal pathway, reducing the expression of inflammatory factors and ROS production, thus inhibiting the inflammatory response of BMECs. Nuclear factor kappa B subunit 1 (NF-κB p50) was an important target of SDC3 in this process. To sum up, our results showed that SDC3 coregulated milk fat metabolism and inflammation through the AMPK/SIRT1 signaling pathway. This study laid a foundation for the comprehensive evaluation of breeding value based on multi-effect functional genes in dairy cow molecular breeding.

Effects of Palladium Precursors on the Activity of Palladium Nanocatalysts for the Oxidation of Volatile Organic Components

To screen a suitable precursor, the effects of palladium salts on performance of Pd nanocatalysts for the oxidation of volatile organic components (VOCs) were investigated. A series of catalysts was prepared by impregnating Pd(NO₃)₂, PdCl₂ and Pd(NH₃)₄Cl₂ on alumina-coated cordierites. These catalysts were characterized by XRF, ICP-OES, XRD, N₂ adsorption-desorption, TEM, EDS, Raman spectroscopy, pulse-CO chemisorption, H₂-TPR, NH₃-TPD, and XPS. Pulse-CO chemisorption and TEM showed that Pd species formed by Pd(NO₃)₂ have the highest metal dispersion (17.7%), while the other two were aggregating. For the same Pd loading, the higher the metal dispersion, the more the number of PdO species, so the number of PdO particles in the catalyst prepared from Pd (NO₃) ₂ is the largest. The catalytic oxidation activities of these catalysts were evaluated by ethane and propane. Based on a 99% conversion in the oxidation of ethane and propane at 598 K and 583 K, respectively, the catalyst prepared from Pd(NO₃)₂ was considered to be the best performing catalyst. The chloride species in precursors can promote the aggregation of Pd species and poison the catalysts. The results show that Pd(NO₃)₂ is more suitable as the precursor of VOC oxidation catalyst than PdCl₂ and Pd(NH₃)₄Cl₂.

A40 GUT MICROBIOTA PROMOTES NUTRIENT AVAILABLITY AND PATHOGENESIS OF AN ATTACHING/ EFFACING BACTERIAL PATHOGEN

Background

Our gut microbiota plays an important role in protecting the gastrointestinal (GI) tract from invading enteric pathogens. Much of this colonization resistance is mediated by limiting nutrient availability, however, enteric pathogens have evolved strategies to subvert this competition, utilizing commensal metabolites to facilitate their infection. Access to nutrients is not only crucial for a pathogen’s metabolic fitness, but can also drive the expression of virulence factors, a process high in energy demands. In addition, enteric pathogens, such as the attaching and effacing (A/E) bacterium Citrobacter rodentium, must cross the colonic mucus layer that normally prevents their direct access to the underlying epithelium. Intestinal mucus is comprised of highly glycosylated mucins, with the sugar sialic acid frequently occupying the terminal position of their O-glycan side chains. We hypothesize that C. rodentium utilizes commensal-liberated mucin sugars, such as sialic acid, as nutrients and signals to promote its virulence.

Purpose

This study investigates the mechanisms by which A/E pathogens reach the colonic mucosal surface, and the role played by commensal microbes in facilitating the infection.

Method

Expression of virulence factors secreted by C. rodentium in the presence or absence of sialic acid was analyzed by SDS-PAGE and mass spectrometry. Next, we infected specific-pathogen free (SPF), germfree (GF), and previously GF C57Bl/6 mice mono-colonized with Bacteroides thetaotaomicron, a mucus-degrading commensal, to examine their susceptibility to C. rodentium and to measure the levels of free sialic acid in their feces.

Result(s)

Sensing of sialic acid by C. rodentium, was found to induce the secretion of several key virulence proteins, enhancing the pathogen’s migration across the colonic mucus layer and adhesion to the underlying epithelium. Access to sialic acid within the gut environment was enhanced in the presence of microbiota, as the levels of free sialic acid were low in GF mice. Interestingly, despite GF mice carrying very high C. rodentium burdens, passage across the mucus layer and infection of their colonic epithelium was impaired as compared to SPF mice. Notably, B. thetaotaomicron was found to degrade whole mucus in vitro, facilitating its consumption by C. rodentium for growth, while B. thetaotaomicron mono-colonized GF mice showed increased susceptibility to colonic infection by C. rodentium.

Conclusion(s)

We demonstrate that although commensal microbes promote colonization resistance, as an A/E pathogen infection establishes, specific commensal bacteria accelerate infection in the GI tract by releasing an important nutrient, ie. sialic acid, from mucus. Access to sialic acid promotes C. rodentium virulence by inducing the key virulence factors that facilitate its translocation across the mucus layer as well as adhesion to the epithelium, thereby expediting disease progression.

Please acknowledge all funding agencies by checking the applicable boxes below

CCC, CIHR, Other

Please indicate your source of funding;

CH.I.L.D. Foundation

Disclosure of Interest

None Declared

A15 GENETIC OR DIET-ASSOCIATED DEFECTS IN MUCUS FACILITATE ULCERATIVE COLITIS PATHOBIONT-DRIVEN COLITIS

Background

The Inflammatory Bowel Diseases (IBD), Crohn’s Disease (CD) and ulcerative colitis (UC) affect > 270,000 Canadians and are increasing in incidence. Ileal CD has been linked to the overgrowth of mucosal adherent E. coli. Recent studies have also implicated the adherence of Escherichia coli pathobionts to the colonic mucosa of UC patients. Using the representative UC E. coli pathobiont p19A, we recently demonstrated it aggravated chemical-induced colitis in susceptible mice, through the actions of the toxin alpha-hemolysin, and by adhering to the inflamed colonic mucosa via the adhesin FimH. It is less clear what host factors control susceptibility to the UC pathobionts. One of the potential candidates is the glycosylated mucin (Muc2) which forms the mucus layer that covers the colonic epithelium and is often impaired in UC patients.

Purpose

To define the role of mucus structure and function in determining susceptibility to the p19A pathobiont, and its ability to cause colitis in mice.

Method

In vitro growth was assessed to test p19A’s ability to utilize mucin-derived sugars as nutrients. Susceptibility to p19A was tested in two mouse models of colonic mucus impairment. The first is a mouse strain deficient in core 1 derived O-glycans in their intestinal epithelial cells (IEC C1galt1^-/-), resulting in reduced Muc2 glycosylation, and thus a thin and impaired mucus barrier. The second model involves feeding wildtype (WT) C57BL/6CR mice a fiber-free (FF) diet, resulting in a significantly thinner colonic mucus layer. The mice were subsequently orally gavaged with p19A and their susceptibility determined by p19A burdens, intestinal histopathology, inflammatory cytokine and short chain fatty acid (SCFA) production.

Result(s)

When tested in vitro, the p19A pathobiont was found to use an array of mucin-derived sugars as sole carbon source to proliferate. Following oral gavage of WT mice fed a normal diet, immunostaining identified p19A within the colonic mucus but it did not reach the colonic mucosa or cause disease. In contrast, p19A was found at the colonic mucosal surface of mucus-defective IEC C1galt1^-/- mice (as compared to IEC C1galt1^flox/flox mice) and in WT mice fed a fiber-free diet. This mucosal adherence was associated with increased body weight loss during the course of infection, as well as increased p19A burdens, colonic pathology and pro-inflammatory cytokine expression. Especially fiber-free diet-fed mice showed reduced SCFA levels in their feces at baseline. When the mice were given exogenous SCFA (tributyrin) orally, p19A infection was reduced.

Conclusion(s)

Our results indicate that UC E. coli pathobionts are able to dwell within colonic mucus and utilize mucin sugars as nutrients. Moreover, they can reach the mucosal surface and induce colitis in hosts suffering genetic or diet-based mucus dysfunction. In part, this susceptibility reflects the important role played by mucus in the production of SCFA, suggesting potential therapeutic approaches for patients suffering UC.

Please acknowledge all funding agencies by checking the applicable boxes below

CCC, CIHR

Disclosure of Interest

None Declared

Efficacy and Safety of Sofosbuvir-based Regimens in Hepatitis C Patients With Decompensated Cirrhosis: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Decompensated cirrhotic patients with hepatitis C (HCV) are often under-represented in clinical trials. We aimed to evaluate pooled data on the efficacy and safety of sofosbuvir (SOF)-based regimens in these patients.

METHODS

We conducted a systemic review and meta-analysis by searching multiple databases for studies published from October 2010 to October 2020. Outcomes of interest were sustained virologic response (SVR) and safety of SOF-based regimens in decompensated HCV patients. Two reviewers independently performed the study selection and data extraction.

RESULTS

We included 33 studies that enrolled 5,302 HCV patients. The pooled SVR rate in decompensated patients with SOF-based regimens was 85.1% (95% CI: 82.8-87.3). Patients on SOF/velpatasvir±ribavirin achieved a significantly higher SVR (91.0%, 95% CI: 87.7-93.9) than that of SOF/ledipasvir±ribavirin [(86.3%, 95% CI: 84.6-87.8); p=0.004)], or on SOF/daclatasvir±ribavirin (82.4%, 95% CI: 78.2-86.2%; p<0.001). Adding ribavirin to SOF-based regimens (pooled SVR 84.9%, 95% CI: 81.7-87.9) did not significantly increase the SVR [(83.8% (95% CI: 76.8-89.8%; p=0.76)] in decompensated patients, which was also true in subgroup analyses for each regimen within the same treatment duration. However, adding ribavirin significantly increased the frequency of adverse events from 52.9% (95% CI: 28.0-77.1) to 89.2% (95% CI: 68.1-99.9) and frequency of severe events. The pooled incidence of hepatocellular carcinoma and case-fatality of decompensated patients were 3.1% (95% CI: 1.5-5.0) and 4.6% (95% CI: 3.1-6.3), respectively. The overall heterogeneity was high. There was no publication bias.

CONCLUSIONS

The analysis found that 12 weeks of SOF/velpatasvir without ribavirin is the preferred therapy, with a significantly higher SVR compared with other SOF-based regimens in decompensated HCV patients.

Open-Ended Online Learning for Autonomous Visual Perception

The visual perception systems aim to autonomously collect consecutive visual data and perceive the relevant information online like human beings. In comparison with the classical static visual systems focusing on fixed tasks (e.g., face recognition for visual surveillance), the real-world visual systems (e.g., the robot visual system) often need to handle unpredicted tasks and dynamically changed environments, which need to imitate human-like intelligence with open-ended online learning ability. Therefore, we provide a comprehensive analysis of open-ended online learning problems for autonomous visual perception in this survey. Based on "what to online learn" among visual perception scenarios, we classify the open-ended online learning methods into five categories: instance incremental learning to handle data attributes changing, feature evolution learning for incremental and decremental features with the feature dimension changed dynamically, class incremental learning and task incremental learning aiming at online adding new coming classes/tasks, and parallel and distributed learning for large-scale data to reveal the computational and storage advantages. We discuss the characteristic of each method and introduce several representative works as well. Finally, we introduce some representative visual perception applications to show the enhanced performance when using various open-ended online learning models, followed by a discussion of several future directions.

Identification of histone acetyltransferase genes responsible for cannabinoid synthesis in hemp

BACKGROUND

Histone acetyltransferases (HATs) play an important role in plant growth and development, stress response, and regulation of secondary metabolite biosynthesis. Hemp (Cannabis sativa L.) is famous for its high industrial, nutritional, and medicinal value. It contains non-psychoactive cannabinoid cannabidiol (CBD) and cannabinol (CBG), which play important roles as anti-inflammatory and anti-anxiety. At present, the involvement of HATs in the regulation of cannabinoid CBD and CBG synthesis has not been clarified.

METHODS

The members of HAT genes family in hemp were systematically analyzed by bioinformatics analysis. In addition, the expression level of HATs and the level of histone acetylation modification were analyzed based on transcriptome data and protein modification data. Real-time quantitative PCR was used to verify the changes in gene expression levels after inhibitor treatment. The changes of CBD and CBG contents after inhibitor treatment were verified by HPLC-MS analysis.

RESULTS

Here, 11 HAT genes were identified in the hemp genome. Phylogenetic analysis showed that hemp HAT family genes can be divided into six groups. Cannabinoid synthesis genes exhibited spatiotemporal specificity, and histones were acetylated in different inflorescence developmental stages. The expression of cannabinoid synthesis genes was inhibited and the content of CBD and CBG declined by 10% to 55% in the samples treated by HAT inhibitor (PU139). Results indicated that CsHAT genes may regulate cannabinoid synthesis through altering histone acetylation.

CONCLUSIONS

Our study provides genetic information of HATs responsible for cannabinoid synthesis, and offers a new approach for increasing the content of cannabinoid in hemp.

[Progress in perioperative management of ABO-incompatible pediatric liver transplantation]

ABO incompatible(ABO-I) liver grafts will affect the prognosis of liver transplantation. With the improvement of perioperative treatment,including plasma exchange,rituximab,splenectomy,etc.,the prognosis of ABO-I liver transplantation has been greatly improved. Because children's immune systems are not fully developed,the perioperative management of ABO-I pediatric liver transplantation is significantly different from that of adults. Reducing the perioperative anti-donor ABO antibody titer is the key to the perioperative management of ABO-I liver transplantation. This article summarizes literatures on the perioperative management of ABO-I pediatric liver transplantation, including the perioperative anti-rejection regimen in pediatric recipients of different ages, splenectomy, postoperative monitoring and postoperative complications, etc.