Structural insights into the unusual core photocomplex from a triply extremophilic purple bacterium, Halorhodospira halochloris

Halorhodospira (Hlr.) halochloris is a triply extremophilic phototrophic purple sulfur bacterium, as it is thermophilic, alkaliphilic, and extremely halophilic. The light-harvesting-reaction center (LH1-RC) core complex of this bacterium displays an LH1-Qy transition at 1,016 nm, which is the lowest-energy wavelength absorption among all known phototrophs. Here we report the cryo-EM structure of the LH1-RC at 2.42 Å resolution. The LH1 complex forms a tricyclic ring structure composed of 16 αβγ-polypeptides and one αβ-heterodimer around the RC. From the cryo-EM density map, two previously unrecognized integral membrane proteins, referred to as protein G and protein Q, were identified. Both of these proteins are single transmembrane-spanning helices located between the LH1 ring and the RC L-subunit and are absent from the LH1-RC complexes of all other purple bacteria of which the structures have been determined so far. Besides bacteriochlorophyll b molecules (B1020) located on the periplasmic side of the Hlr. halochloris membrane, there are also two arrays of bacteriochlorophyll b molecules (B800 and B820) located on the cytoplasmic side. Only a single copy of a carotenoid (lycopene) was resolved in the Hlr. halochloris LH1-α3β3 and this was positioned within the complex. The potential quinone channel should be the space between the LH1-α3β3 that accommodates the single lycopene but does not contain a γ-polypeptide, B800 and B820. Our results provide a structural explanation for the unusual Qy red shift and carotenoid absorption in the Hlr. halochloris spectrum and reveal new insights into photosynthetic mechanisms employed by a species that thrives under the harshest conditions of any phototrophic microorganism known.

Silver frameworks based on a tetraphenylethylene-imidazole ligand for electrocatalytic reduction of CO2 to CO

Metal-organic frameworks (MOFs) can be used as electrocatalysts for the CO2 reduction reaction (CO2RR) because of their well-dispersed metal centers. Silver is a common electrocatalyst for reduction of CO2 to CO. In this study, two Ag-MOFs with different structures of [Ag8O2(TIPE)6](NO3)4 (Ag-MOF1) and [Ag(TIPE)0.5CF3SO3] (Ag-MOF2) [TIPE = 1,1,2,2-tetrakis(4-(imidazol-1-yl)phenyl)ethene] were synthesized and used for CO2 electroreduction. The results show that Ag-MOF2 is superior to Ag-MOF1 and exhibits high CO faradaic efficiency (FE) of 92.21% with partial current density of 29.51 mA cm-2 at -0.98 V versus reversible hydrogen electrode (RHE). The FECO is higher than 80% in the potential range of -0.78 to -1.18 V. The difference may be caused by different framework structures leading to different electrochemical active surface areas and charge transfer kinetics. This study provides a new strategy for designing and constructing CO2 electroreduction catalysts and provides potential ways for solving environmental and energy problems caused by excessive CO2 emission.

Effect and Mechanism of Curdione Combined with Gemcitabine on Migration and Invasion of Bladder Cancer

Bladder cancer (BCa), which usually occurs in bladder epithelial cells and is the fifth most common type of cancer in the world. he recurrence rate within 5 years after surgery is 0.8-45% of patients with early bladder cancer. Therefore, finding appropriate drug therapy for patients with bladder cancer can provide a reference for clinical treatment and play an important role in improving the prognosis of patients. In this study, CCK8 assay result showed that the inhibition of bladder cancer cell activity by Curdione and GEM increased with time and dose. Subsequently, CCK8, clone formation assay and Transwell result showed Curdione enhances GEM inhibition of bladder cancer cell activity, clonal formation and migration, these combine therapeutic schedule also could inhibited growth of in vivo xenograft tumors. The comprehensive database showed that CA2 is a potential target genes of Curdione, and Knockdown CA2 enhances GEM induced inhibition of cell proliferation and migration. Based on these advantages, Curdione may be a new type of action drug or adjunct for the treatment of bladder cancer.

Exploring a new mechanism between lactate and VSMC calcification: PARP1/POLG/UCP2 signaling pathway and imbalance of mitochondrial homeostasis

Lactate leads to the imbalance of mitochondria homeostasis, which then promotes vascular calcification. PARP1 can upregulate osteogenic genes and accelerate vascular calcification. However, the relationship among lactate, PARP1, and mitochondrial homeostasis is unclear. The present study aimed to explore the new molecular mechanism of lactate to promote VSMC calcification by evaluating PARP1 as a breakthrough molecule. A coculture model of VECs and VSMCs was established, and the model revealed that the glycolysis ability and lactate production of VECs were significantly enhanced after incubation in DOM. Osteogenic marker expression, calcium deposition, and apoptosis in VSMCs were decreased after lactate dehydrogenase A knockdown in VECs. Mechanistically, exogenous lactate increased the overall level of PARP and PARylation in VSMCs. PARP1 knockdown inhibited Drp1-mediated mitochondrial fission and partially restored PINK1/Parkin-mediated mitophagy, thereby reducing mitochondrial oxidative stress. Moreover, lactate induced the translocation of PARP1 from the nucleus to the mitochondria, which then combined with POLG and inhibited POLG-mediated mitochondrial DNA synthesis. This process led to the downregulation of mitochondria-encoded genes, disturbance of mitochondrial respiration, and inhibition of oxidative phosphorylation. The knockdown of PARP1 could partially reverse the damage of mitochondrial gene expression and function caused by lactate. Furthermore, UCP2 was upregulated by the PARP1/POLG signal, and UCP2 knockdown inhibited Drp1-mediated mitochondrial fission and partially recovered PINK1/Parkin-mediated mitophagy. Finally, UCP2 knockdown in VSMCs alleviated DOM-caused VSMC calcification in the coculture model. The study results thus suggest that upregulated PARP1 is involved in the mechanism through which lactate accelerates VSMC calcification partly via POLG/UCP2-caused unbalanced mitochondrial homeostasis.

New insights on the photocomplex of Roseiflexus castenholzii revealed from comparisons of native and carotenoid-depleted complexes

In wild-type phototrophic organisms, carotenoids (Crts) are primarily packed into specific pigment-protein complexes along with (Bacterio)chlorophylls and play important roles in the photosynthesis. Diphenylamine (DPA) inhibits carotenogenesis but not phototrophic growth of anoxygenic phototrophs and eliminates virtually all Crts from photocomplexes. To investigate the effect of Crts on assembly of the reaction center-light-harvesting (RC-LH) complex from the filamentous anoxygenic phototroph Roseiflexus (Rfl.) castenholzii, we generated carotenoidless (Crt-less) RC-LH complexes by growing cells in the presence of DPA. Here, we present cryo-EM structures of the Rfl. castenholzii native and Crt-less RC-LH complexes with resolutions of 2.86 Å and 2.85 Å, respectively. From the high-quality map obtained, several important but previously unresolved details in the Rfl. castenholzii RC-LH structure were determined unambiguously including the assignment and likely function of three small polypeptides, and the content and spatial arrangement of Crts with bacteriochlorophyll molecules. The overall structures of Crt-containing and Crt-less complexes are similar. However, structural comparisons showed that only five Crts remain in complexes from DPA-treated cells and that the subunit X (TMx) flanked on the N-terminal helix of the Cyt-subunit is missing. Based on these results, the function of Crts in the assembly of the Rfl. castenholzii RC-LH complex and the molecular mechanism of quinone exchange is discussed. These structural details provide a fresh look at the photosynthetic apparatus of an evolutionary ancient phototroph as well as new insights into the importance of Crts for proper assembly and functioning of the RC-LH complex.

Sinomenine ameliorates rheumatoid arthritis by modulating tryptophan metabolism and activating aryl hydrocarbon receptor via gut microbiota regulation

Gut microbiota dysbiosis is associated with the development of rheumatoid arthritis (RA). Sinomenine (SIN) is an effective immunosuppressive and anti-inflammatory drug used for treating RA, but how SIN regulates gut microbiota to alleviate RA remains underexplored. To identify the critical gut microbial species and microbial metabolites associated with the RA-protective effects of SIN, the microbiota-dependent anti-RA effects of SIN were assessed by 16S rRNA gene sequencing, antibiotic treatment, and fecal microbiota transplantation. Metabolomics analysis, transcriptional analysis, and targeted bacteria/metabolites gavage were conducted to explore how SIN regulates gut microbiota to reduce the severity of RA. SIN could restore intestinal microbial balance by mainly modulating the abundance of Lactobacillus, and significantly relieve collagen-induced arthritis (CIA) symptoms in a gut microbiota-dependent manner. SIN significantly elevated microbial tryptophan metabolites indole-3-acrylic acid (IA), indole-3-propionic acid (IPA), and indole-3-acetic acid (IAA). Tryptophan metabolites supplementation could activate aryl hydrocarbon receptor (AhR) and regulate Th17/Treg balance in CIA rats. Intriguingly, SIN relieved the arthritis symptoms involving the enrichment of two beneficial anti-CIA Lactobacillus species, L. paracasei and L. casei by mono-colonization. The promising therapeutic function of SIN was mostly attributed to the activation of AhR by explicitly targeting the Lactobacillus and microbial tryptophan metabolites. The intestinal bacterium L. paracasei and L. casei may be used to reduce the severity of CIA.

LINC00346 regulates NLRP1-mediated pyroptosis and autophagy via binding to microRNA-637 in vascular endothelium injury

Endothelial injury and dysfunction contributes to atherosclerosis. LINC00346 plays a key role in vascular endothelial cell injury, however, the specific mechanism remains unclear. This study intends to further explore the relationship between LINC00346 and vascular endothelial injury. Circulating LINC00346 was significantly elevated in patients with coronary artery disease and had high diagnostic value for coronary artery disease. In cell experiments, we found that LINC00346 expression was significantly increased in the oxidized low-density lipoprotein (ox-LDL) intervention group, and LINC00346 knockdown delayed ox-LDL induced human umbilical vein endothelial cell (HUVEC) endothelial-to-mesenchymal transition. In addition, knockdown of LINC00346 mitigated ox-LDL-induced NOD-like receptor protein 1 (NLRP1)-mediated inflammasome formation and pyroptosis, but had no significant effect on NLRP3. By observing the number of autophagosome and detecting intracellular autophagic flux, we found that LINC00346 knockdown inhibited the ox-LDL-induced increase in intracellular autophagy level. Dual-luciferase reporter assay, RNA immunoprecipitation assay, and RNA-pull down assay were performed to confirm the inter-molecular interaction. LINC00346 acted as microRNA-637 sponge to up-regulate the expression of NLRP1. Up-regulation of microRNA-637 alleviated NLRP1-mediated pyroptosis in HUVEC and reduced intracellular autophagosome and autolysosome formation. Finally, we explored whether pyropotosis and autophagy interact with each other. We found that inhibition of intracellular autophagy could alleviate NLRP1-mediated pyroptosis. In conclusion, LINC00346 inhibited the activation of NLRP1-mediated pyroptosis and autophagy via binding to microRNA-637, therefore mitigating vascular endothelial injury.

Development and validation of a coagulation-related genes prognostic model for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) has a high incidence and mortality worldwide, which seriously threatens people's physical and mental health. Coagulation is closely related to the occurrence and development of HCC. Whether coagulation-related genes (CRGs) can be used as prognostic markers for HCC remains to be investigated.

METHODS

Firstly, we identified differentially expressed coagulation-related genes of HCC and control samples in the datasets GSE54236, GSE102079, TCGA-LIHC, and Genecards database. Then, univariate Cox regression analysis, LASSO regression analysis, and multivariate Cox regression analysis were used to determine the key CRGs and establish the coagulation-related risk score (CRRS) prognostic model in the TCGA-LIHC dataset. The predictive capability of the CRRS model was evaluated by Kaplan-Meier survival analysis and ROC analysis. External validation was performed in the ICGC-LIRI-JP dataset. Besides, combining risk score and age, gender, grade, and stage, a nomogram was constructed to quantify the survival probability. We further analyzed the correlation between risk score and functional enrichment, pathway, and tumor immune microenvironment.

RESULTS

We identified 5 key CRGs (FLVCR1, CENPE, LCAT, CYP2C9, and NQO1) and constructed the CRRS prognostic model. The overall survival (OS) of the high-risk group was shorter than that of the low-risk group. The AUC values for 1 -, 3 -, and 5-year OS in the TCGA dataset were 0.769, 0.691, and 0.674, respectively. The Cox analysis showed that CRRS was an independent prognostic factor for HCC. A nomogram established with risk score, age, gender, grade, and stage, has a better prognostic value for HCC patients. In the high-risk group, CD4⁺T cells memory resting, NK cells activated, and B cells naive were significantly lower. The expression levels of immune checkpoint genes in the high-risk group were generally higher than that in the low-risk group.

CONCLUSIONS

The CRRS model has reliable predictive value for the prognosis of HCC patients.

Comparison of ischemic stroke diagnosis models based on machine learning

Background

The incidence, prevalence, and mortality of ischemic stroke (IS) continue to rise, resulting in a serious global disease burden. The prediction models have a great value in the early prediction and diagnosis of IS.

Methods

The R software was used to screen the differentially expressed genes (DEGs) of IS and control samples in the datasets GSE16561, GSE58294, and GSE37587 and analyze DEGs for enrichment analysis. The feature genes of IS were obtained by several machine learning algorithms, including the least absolute shrinkage and selector operation (LASSO) logistic regression, the support vector machine-recursive feature elimination (SVM-RFE), and the Random Forest (RF). The IS diagnostic models were constructed based on transcriptomics by machine learning and artificial neural network (ANN).

Results

A total of 69 DEGs, mainly involved in immune and inflammatory responses, were identified. The pathways enriched in the IS group were complement and coagulation cascades, lysosome, PPAR signaling pathway, regulation of autophagy, and toll-like receptor signaling pathway. The feature genes selected by LASSO, SVM-RFE, and RF were 17, 10, and 12, respectively. The area under the curve (AUC) of the LASSO model in the training dataset, GSE22255, and GSE195442 was 0.969, 0.890, and 1.000. The AUC of the SVM-RFE model was 0.957, 0.805, and 1.000, respectively. The AUC of the RF model was 0.947, 0.935, and 1.000, respectively. The models have good sensitivity, specificity, and accuracy. The AUC of the LASSO+ANN, SVM-RFE+ANN, and RF+ANN models was 1.000, 0.995, and 0.997, respectively, in the training dataset. However, the AUC of LASSO+ANN, SVM-RFE+ANN, and RF+ANN models was 0.688, 0.605, and 0.619, respectively, in the GSE22255 dataset. The AUC of the LASSO+ANN and RF+ANN models was 0.740 and 0.630, respectively, in the GSE195442 dataset. In the training dataset, the sensitivity, specificity, and accuracy of the LASSO+ANN model were 1.000, 1.000, and 1.000, respectively; of the SVM-RFE+ANN model were 0.946, 0.982, and 0.964, respectively; and of the RF+ANN model were 0.964, 1.000, and 0.982, respectively. In the test datasets, the sensitivity was very satisfactory; however, the specificity and accuracy were not good.

Conclusion

The LASSO, SVM-RFE, and RF models have good prediction abilities. However, the ANN model is efficient at classifying positive samples and is unsuitable at classifying negative samples.

[Analysis of clinical and endoscopic characteristics of colorectal polyps in children]

To analyze the clinical and endoscopic characteristics of colorectal polyps in children, and to explore the detection rate, age and gender distribution characteristics, endoscopic treatment effect and follow-up monitoring of colorectal polyps in children, so as to provide reference for disease management of colorectal polyps in children. The clinical and endoscopic characteristics of children with colorectal polyps in Xi 'an Children's Hospital from January 2019 to December 2019 were retrospectively analyzed. The patients were divided into 5 groups according to age (y): 0<y<1 years, 1≤ y<4 years, 4≤ y<7 years, 7≤ y<12 years, and 12≤ y ≤18 years. Independent sample t test, Pearson Chi-square test (χ²) were used to compare groups' differences. The results showed that a total of 724 colonoscopies were completed in 2019, and 160 colorectal polyps were diagnosed, with a detection rate of 22.10%. Among the children with colorectal polyps, 105 were males, accounting for 65.62%, and 55 were females, accounting for 34.38%. The detection rate of male colorectal polyps was 22.68%, and the detection rate of female colorectal polyps was 21.08%. There was no significant difference in the detection rate of colorectal polyps between males and females (χ² = 0.25, P =0.617). Children with colorectal polyps were most common in the age group of 1≤ y<4 years, 72 cases, accounting for 41.14%(72/175). The detection rate of colorectal polyps in different age groups was statistically significant (χ²=73.929, P<0.05). The main symptom of children with colorectal polyps was hematochezia, accounting for 87.5% (140/160). Colorectal polyps were mainly single polyps in 140 patients, accounting for 87.50%, 15 patients had 2-4 polyps, accounting for 9.38%, and 5 patients had 5 or more polyps, accounting for 3.12%. A total of 210 polyps were removed, and the most common site of polyps was rectum, 123 polyps, accounting for 58.57% (123/210). 111 (52.86%, 111/210) of them were 1 cm to 2 cm in diameter. The Yamada classification was mainly type Ⅲ, 114 pieces, accounting for 54.29% (114/210). Among the 210 polyps with diameter ≥0.5 cm, 165 were removed by endoscopic mucosal resection, accounting for 78.57% (165/210). There were 23 patients with postoperative complications, including hematochezia, abdominal pain, fever, vomiting, diarrhea, dizziness, and no gastrointestinal perforation. Juvenile polyps were the main pathological type, accounting for 88.13% (141/160). The children with juvenile polyps were followed up for 3-30 months, and recurrence was considered in 2 of them. In conclusion, the detection rate of colorectal polyps in children aged 1≤ y<4 years is high, and hematochezia is the main clinical manifestation. Standardized endoscopic treatment and follow-up monitoring are very important for children with colorectal polyps.

Effectiveness and Safety of Rifaximin-Containing Regimens for Helicobacter pylori Eradication: Systematic Review - Are They Potential Eradication Regimens?

Background

Rifaximin, a rifamycin antibiotic, is widely used to treat infectious diarrhea but not commonly used in H. pylori eradication. With its potential advantages of the agent, some studies were conducted on this topic. The aim of this study is to assess effectiveness and safety of rifaximin-containing regimens and to evaluate whether they are alternative choices for H. pylori eradication.

Methods

Scientific databases including PubMed, EMbase and Cochrane Library were used to identify clinical trials on rifaximin-containing regimens published from January 2000 to October 2021. Review Manager 5.4 and STATA12 were adopted for the systematic review.

Results

In this study, totally 1025 patients were included from 3 randomized controlled and 9 single-arm studies. It showed that the differences in effectiveness and safety between rifaximin-containing and first-line regimens were not statistically significant in randomized controlled trials. However, the results of the single-arm trials indicated that the eradication and adverse drug reaction rate varied suggesting data instability (r=38.1%-85.4%, r_ADR 0.00–67.5% by ITT analysis). Among them, the eradication rate of pediatric patients (r=85.4% by ITT analysis) was higher than that of adult patients (r=38.1–74.5% by ITT analysis). Meanwhile, in all adult subgroups (triple or quadruple, with or without amoxicillin, different duration and rifaximin dose), the results did not show sufficient effectiveness as all the eradication rates did not meet the minimum ideal or ideal target.

Conclusion

Taken together, rifaximin-containing regimens should not be recommended for H. pylori eradication as they cannot achieve the eradication rate desired.

[Preoperative serum creatinine as an independent prognostic biomarker in patients with early-stage cervical adenocarcinoma]

Objective: To investigate the effect of preoperative serum creatinine (Scr) level on the prognosis of patients with early cervical adenocarcinoma (ADC) and its predictive value. Methods: A retrospective review was performed on 199 patients with the International Federation of Gynecology and Obstetrics (FIGO) stage ⅠA1-ⅡA1 and pathology-proven invasive ADC from January 2005 to December 2015. Patients were followed up by phone and outpatient, with a median follow-up time 77.5 (57.0, 114.0) months, 11 cases (5.5%) were missing, 19 cases (10.1%) recurred, and 17 cases (9.0%) died. Multivariate analysis was performed by Cox regression model to analyze the related factors of the prognosis of ADC patients. The optimal cut-off point was determined by the analysis of receiver operating characteristics (ROC), and the predictive value of related factors for prognosis was evaluated by the area under the curve (AUC). Results: The median age of 199 patients was 44.0 (39.0-50.0) years. Overall, 16 patients (8.0%) were stage ⅠA1; 4 patients (2.0%) were stage ⅠA2; 147 patients (74.0%) were stage ⅠB1; 13 patients (6.5%) were stage ⅠB2; 19 patients (9.5%) were stage ⅡA1. The multivariate analysis showed that FIGO stage [4.570 (1.625-12.854)] and elevated Scr [1.065 (1.006-1.128)] were correlated with DFS in patients with early ADC, as well as correlated with OS [4.412 (1.458-13.350) and 1.076 (1.012-1.144), respectively (all P<0.05)]. The optimal cut-off point of Scr level was 75.2 μmoI/L. The AUC showed that the Scr level was a predictor of DFS (AUC=0.677, 95%CI: 0.608-0.742, P=0.006) and OS (AUC=0.677, 95%CI: 0.607-0.741, P=0.012). Conclusions: The preoperative Scr level independently predicts the prognosis of early-stage ADC; patients with Scr levels>75.2 μmoL/L might require more follow-up and adjuvant treatment, as they might have a poorer prognosis.

Theoretical understanding on all-solid frustrated Lewis pair sites of C2N anchored by single metal atom

Designing all-solid heterogeneous catalysts with frustrated Lewis pairs (FLPs) has aroused great attentions recently because of its appealing low dissociation energy for H2 molecule and thus a promotion of hydrogenation reaction is expected. The sterically encumbered Lewis acid (metal site) and base (nitrogen site) in the cavity of single transition metal atom doped M/C2N sheet makes it potential candidate with FLP, while a comprehensive understanding of its intrinsic property and reactivity is still required. Calculations show that the complete dissociation of H2 molecule into two H* at the N sites requires two steps, i.e., heterolytic cleavage of H2 molecule and the transfer of H* from metal site to N site, which are highly related to the acidity of the metal site. The Ni/C2N and Pd/C2N, which outperform over the other 8 transition metal atom (M) anchored M/C2N candidates, possess low energy barriers for the complete dissociation of H2 molecule, with values of only 0.30 and 0.20 eV, respectively. Furthermore, both Ni/C2N and Pd/C2N catalysts can achieve semi-hydrogenation of C2H2 into C2H4, with overall barriers of 0.81 and 0.75 eV, respectively, lower than many reported catalysts. It is speculated that M/C2N catalysts with intrinsic FLPs may also find applications in other important hydrogenation reaction.

Short term outcomes of extremely low birth weight infants from a multicenter cohort study in Guangdong of China

With the increase in extremely low birth weight (ELBW) infants, their outcome attracted worldwide attention. However, in China, the related studies are rare. The hospitalized records of ELBW infants discharged from twenty-six neonatal intensive care units in Guangdong Province of China during 2008-2017 were analyzed. A total of 2575 ELBW infants were enrolled and the overall survival rate was 55.11%. From 2008 to 2017, the number of ELBW infants increased rapidly from 91 to 466, and the survival rate improved steadily from 41.76% to 62.02%. Increased survival is closely related to birth weight (BW), regional economic development, and specialized hospital. The incidence of complications was neonatal respiratory distress syndrome (85.2%), oxygen dependency at 28 days (63.7%), retinopathy of prematurity (39.3%), intraventricular hemorrhage (29.4%), necrotizing enterocolitis (12.0%), and periventricular leukomalacia (8.0%). Among the 1156 nonsurvivors, 90.0% of infants died during the neonatal period (≤ 28 days). A total of 768 ELBW infants died after treatment withdrawal, for reasons of economic and/or poor outcome. The number of ELBW infants is increasing in Guangdong Province of China, and the overall survival rate is improving steadily.

Identification of antidiabetic components in Uncariae Rammulus Cum Uncis based on phytochemical isolation and spectrum-effect relationship analysis

OBJECTIVES

Uncariae Rammulus Cum Uncis (URCU) is a commonly used herbal medicine to treat diabetes. This work is aimed to discover and identify the antidiabetic components from URCU extract.

METHODS

Column chromatography and recrystallisation were used to separate individual compounds from URCU extract, and the obtained individual compounds were used for determination of α-glucosidase inhibitory activity. Molecular docking was applied to predict the molecular interactions. High-performance liquid chromatography (HPLC) was used for fingerprint analysis of 12 batches of URCU. HPLC fingerprints were assessed by the similarity analysis (SA) and hierarchical clustering analysis (HCA). The spectrum-effect relationship analysis of URCU was assessed by orthogonal partial least squares (OPLS) and bivariate correlation analysis (BCA).

RESULTS

A total of 10 potential bioactive compounds were isolated and six of them showed potent α-glucosidase inhibitory activity (IC₅₀  = 4.21-166.10 μM). The molecular docking results revealed that the binding energy was consistent with the results of α-glucosidase inhibition activity analysis (-8.55 to -4.84 kcal/mol). The ethanol extracts of the 12 batches of URCU showed inhibitory effect on α-glucosidase in a dose-dependent manner, and the IC₅₀ values ranged from 0.94 μg/mL to 12.57 μg/mL. The spectrum-effect relationship analysis results indicated that 13 peaks might be potential antidiabetic compounds in URCU, including 18 (hyperoside) and 19 (rutin).

CONCLUSION

A comprehensive connection between URCU chemical components and α-glucosidase inhibitory activity was established for the first time by using a spectrum-effect relationship model, which might be applicable to the quality control of URCU.

Mechanism of Catalytic Transfer Hydrogenation for Furfural Using Single Ni Atom Catalysts Anchored to Nitrogen-Doped Graphene Sheets

Catalytic transfer hydrogenation (CTH) of α,β-unsaturated aldehydes using single metal atom catalysts supported on nitrogen-incorporated graphene sheet (M-N_x-Gr) materials has attracted increasing attention recently, yet the reaction mechanism remains to be explored. Compared to the Ni-N₄-Gr model in which the dissociation of isopropanol is highly unfavorable as a result of steric hindrance and inertness of the Ni-N₄ site embedded in graphene, the Ni-N₃ site in Ni-N₃-Gr is more active and facilitates the formation of *H with isopropanol as the H donor, where the dissociation of H from isopropanol with an energy barrier of 0.83 eV is the rate-determining step. An alternative reaction path starts from the coadsorption of isopropanol and furfural molecules at the Ni-N₃ site, followed by a direct hydrogen transfer between the two molecules; however, the rate-determining step has a much higher energy barrier of 1.32 eV. Our calculations suggest that the hydrogenation of the aldehyde group is kinetically more favorable than the C═C hydrogenation, revealing the high chemoselectivity of furfural to furfuryl alcohol. Our investigations reveal that the CTH mechanism using the Ni-N₃-Gr catalyst is different from that on traditional metal oxides, where the former has only one single active site, while two active sites are required for the latter. The proposed reaction mechanism of CTH for furfural in this study should be helpful to guide the design of single metal atom catalysts with appropriate N coordination for application in chemoselective hydrogenation reactions.

Yellow nail syndrome accompanied by minimal-change nephrotic syndrome: A case report

BACKGROUND

In most cases of yellow nail syndrome (YNS), the classic triad of yellow nails, lymphedema and respiratory manifestations rarely manifest simultaneously. Therefore, diagnosis is delayed or frequently missed.

CASE SUMMARY

We report a 62-year-old YNS patient presenting with bilateral pleural, pericardial and peritoneal effusions who, 2 mo later, developed minimal-change nephrotic syndrome. After treatment with vitamin E, clarithromycin and prednisone for 3 mo, effusions in the chest, pericardium and abdominal cavity decreased while urine protein levels returned to within normal ranges.

CONCLUSION

Clinicians should consider the possibility of YNS for patients presenting with multiple serous effusions and nephrotic syndromes.

Natural selenium stress influences the changes of antibiotic resistome in seleniferous forest soils

BACKGROUND

Metal(loid)s can promote the spread and enrichment of antibiotic resistance genes (ARGs) in the environment through a co-selection effect. However, it remains unclear whether exposure of microorganisms to varying concentrations of selenium (Se), an essential but potentially deleterious metal(loid) to living organisms, can influence the migration and distribution of ARGs in forest soils.

RESULTS

Precisely 235 ARGs conferring resistance to seven classes of antibiotics were detected along a Se gradient (0.06-20.65 mg kg^-1) across 24 forest soils. (flor)/(chlor)/(am)phenicol resistance genes were the most abundant in all samples. The total abundance of ARGs first increased and then decreased with an elevated available Se content threshold of 0.034 mg kg^-1 (P = 2E-05). A structural equation model revealed that the dominant mechanism through which Se indirectly influences the vertical migration of ARGs is by regulating the abundance of the bacterial community. In addition, the methylation of Se (mediated by tehB) and the repairing of DNA damages (mediated by ruvB and recG) were the dominant mechanisms involved in Se resistance in the forest soils. The co-occurrence network analysis revealed a significant correlated cluster between Se-resistance genes, MGEs and ARGs, suggesting the co-transfer potential. Lelliottia amnigena YTB01 isolated from the soil was able to tolerate 50 μg mL^-1 ampicillin and 1000 mg kg^-1 sodium selenite, and harbored both Se resistant genes and ARGs in the genome.

CONCLUSIONS

Our study demonstrated that the spread and enrichment of ARGs are enhanced under moderate Se pressure but inhibited under severe Se pressure in the forest soil (threshold at 0.034 mg kg^-1 available Se content). The data generated in this pilot study points to the potential health risk associated with Se contamination and its associated influence on ARGs distribution in soil.

Disturbance of serum lipid metabolites and potential biomarkers in the Bleomycin model of pulmonary fibrosis in young mice

Background

Altered metabolic pathways have recently been considered as potential drivers of idiopathic pulmonary fibrosis (IPF) for the study of drug therapeutic targets. However, our understanding of the metabolite profile during IPF formation is lacking.

Methods

To comprehensively characterize the metabolic disorders of IPF, a mouse IPF model was constructed by intratracheal injection of bleomycin into C57BL/6J male mice, and lung tissues from IPF mice at 7 days, 14 days, and controls were analyzed by pathology, immunohistochemistry, and Western Blots. Meanwhile, serum metabolite detections were conducted in IPF mice using LC–ESI–MS/MS, KEGG metabolic pathway analysis was applied to the differential metabolites, and biomarkers were screened using machine learning algorithms.

Results

We analyzed the levels of 1465 metabolites and found that more than one-third of the metabolites were altered during IPF formation. There were 504 and 565 metabolites that differed between M7 and M14 and controls, respectively, while 201 differential metabolites were found between M7 and M14. In IPF mouse sera, about 80% of differential metabolite expression was downregulated. Lipids accounted for more than 80% of the differential metabolite species with down-regulated expression. The KEGG pathway enrichment analysis of differential metabolites was mainly enriched to pathways such as the metabolism of glycerolipids and glycerophospholipids. Eight metabolites were screened by a machine learning random forest model, and receiver operating characteristic curves (ROC) assessed them as ideal diagnostic tools.

Conclusions

In conclusion, we have identified disturbances in serum lipid metabolism associated with the formation of pulmonary fibrosis, contributing to the understanding of the pathogenesis of pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01972-6.

[Multimodal Magnetic Resonance and Fluorescence Imaging of the Induced Pluripotent Stem Cell Transplantation in the Brain]

The understanding of the engrafted cell behaviors such as the survival, growth and distribution is the prerequisite to optimize cell therapy, and a multimodal imaging at both anatomical and molecular levels is designed to achieve this goal. We constructed a lentiviral vector carrying genes of ferritin heavy chain 1 (FTH1), near-infrared fluorescent protein (iRFP) and enhanced green fluorescent protein (egfp), and established the induced pluripotent stem cells (iPSCs) culture stably expressing these three reporter genes. These iPSCs showed green and near-infrared fluorescence as well as the iron uptake capacity in vitro. After transplanted the labeled iPSCs into the rat brain, the engrafted cells could be in vivo imaged using magnetic resonance imaging (MRI) and near-infrared fluorescent imaging (NIF) up to 60 days at the anatomical level. Moreover, these cells could be detected using EGFP immunostaining and Prussian blue stain at the cellular level. The developed approach provides a novel tool to study behaviors of the transplanted cells in a multi-modal way, which will be valuable for the effectiveness and safety evaluation of cell therapy.

KLF2 mediates the suppressive effect of BDNF on diabetic intimal calcification by inhibiting HK1 induced endothelial-to-mesenchymal transition

Diabetic vascular calcification in the arterial intima is closely associated with endothelial-to-mesenchymal transition (EndMT). Glucose metabolism reprogramming is involved in EndMT. Although brain-derived neurotrophic factor (BDNF) and Krüppel-like family of transcription factor 2 (KLF2) play protective roles in the physiological activity of the vascular endothelium, the underlying mechanisms are unclear. Human umbilical vein endothelial cells (HUVECs) were incubated with diabetic osteogenic medium (DOM) to induce EndMT and accelerate osteogenic differentiation. Glycolysis in HUVECs was assessed by monitoring glucose uptake, lactate production, extracellular acidification rate and expression of key glycolytic enzymes. DOM induced EndMT and accelerated osteo-induction in HUVECs, which was alleviated by BDNF/tropomyosin receptor kinase B (TrkB) pathway. Mechanistically, DOM caused hyperactivation of glycolysis in HUVECs and inhibition of the BDNF/TrkB pathway. BDNF preserved KLF2 and downregulated hexokinase 1 (HK1) in HUVECs after DOM treatment. Furthermore, KLF2 interacted with HK1. Increased KLF2 alleviated HK1-mediated glucose metabolism abnormality. HK1 knockdown or a targeted glycolysis inhibitor suppressed EndMT, apoptosis, inflammation and vascular calcification of HUVECs after DOM exposure. This study suggests that KLF2 mediates the suppressive effect of BDNF on diabetic intimal calcification by inhibiting HK1-induced glucose metabolism reprogramming and the EndMT process.

The Survival Rate of Extremely Low Birth Weight Infants Improved in Guangdong Province, China.. [DOI: 10.21203/rs.3.rs-1019118/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background With the increase in extremely low birth weight (ELBW) infants, their outcomes received special attention. However, in China, studies of the outcomes of ELBW infants are rare. Methods The hospitalized records of ELBW infants discharged from twenty-six neonatal intensive care units were reviewed and analyzed. Results A total of 2575 ELBW infants were enrolled and the overall survival rate was 55.11%. From 2008 to 2017, the number of ELBW infants increased rapidly from 91 to 466, and the survival rate improved steadily from 41.76–62.02%. The survival rate rose with increasing BW, the ascending level of regional economic development and specialist hospitals. The incidence of complications was neonatal respiratory distress syndrome (85.2%), bronchopulmonary dysplasia (63.7%), retinopathy of prematurity (39.3%), intraventricular hemorrhage (29.4%), necrotizing enterocolitis (12.0%), and periventricular leukomalacia (8.0%). Among the 1156 nonsurvivors, 90.0% of infants died during the neonatal period (≤ 28 days), and the other died after the neonatal period. A total of 768 ELBW infants died after medical care withdrawal, with economic factors and expected outcome being important causes. Conclusion The number of ELBW infants is increasing in China, and the overall survival rate is still low but is improving steadily.

[Transoral endoscopic resection of benign tumors in parapharyngeal space via medial pterygomandibular raphe approach]

Objective: To explore the surgical methods and effects of transoral endoscopic resection of benign tumors in parapharyngeal space via medial pterygomandibular raphe approach. Methods: The clinical data of 23 patients who underwent resection of benign tumors in parapharyngeal space by endoscopic medial pterygomandibular raphe approach from January 2016 to July 2020 in the Department of Otorhinolaryngology Head and Neck Surgery, the Affiliated Hospital of Qingdao University were analyzed retrospectively. There were 14 males and 9 females with a median age of 43 years. The tumors were located in the anterior space of the styloid process in 13 cases and in the posterior space in 10 cases. The smallest tumor volume was 7.3 ml and the largest was 80.2 ml. The preoperative imaging features, the characteristics and risks of this approach in the operation were analyzed, and the feasible mode of operation was explored. Results: All patients completed the operation successfully. The intraoperative blood loss was 20 to 50 ml, with an average of 28.3 ml. The operation time was 40 to 110 min, with an average of 75.4 min. The incision length was 2 to 4 cm, with an average of 3.0 cm. The postoperative pain score was 2 to 4, with an average of 3.2. The postoperative hospital stay was 4 to 9 d, with an average of 6.7 d. Postoperative pathological diagnosis included pleomorphic adenoma (n=12), neurilemmoma (n=10) and basal cell adenoma (n=1). The patients were followed up for 6 to 60 months. There was no postoperative complication such as infection or serious bleeding, and there was no tumor recurrence after operation. Conclusion: Endoscopic resection of benign tumor in parapharyngeal space via medial pterygomandibular raphe approach is a safe, effective, and minimally invasive surgical method for the treatment of tumors in parapharyngeal space.

[Clinical application of expanded noninvasive prenatal testing for fetal chromosome abnormalities]

To assess the positive predictive value (PPV) of extended noninvasive prenatal testing (NIPT-plus) for fetal chromosomal abnormalities. This retrospective research enrolled 511 cases of pregnant women with positive NIPT-plus results at the Obstetrics and Gynecology Hospital of Fudan University from May 2017 to January 2021. Karyotype analysis and chromosome microarray analysis (CMA) techniques was applied for verification. All cases were followed to determine their pregnancy outcome. The Chi-square test was used in PPV. 63 out of 511 refused prenatal diagnosis after counseling, 448 pregnant women with prenatal diagnosis showed that the PPVs of NIPT-plus test for fetal trisomy 21, 18 and 13 (T21, T18, T13), sex chromosome aneuploidy (SCAs) and chromosome microdeletion/microduplication syndrome (MMS) were 86.0% (92/107), 79.5% (35/44), 54.5% (12/22), 39.5% (75/190), and 41.7% (30/72), respectively. The results revealed that the PPV was higher among older pregnant women compared to young pregnant women (77.8% vs. 51.9%,P<0.01). With increasing maternal age, the PPV of NIPT-plus presented increasing trends for T21, T13, and composite PPV except for T18 or SCAs. In addition, the termination rates for confirmed SCAs fetal karyotypes 45, X; 47, XXX; 47, XXY and 47, XYY were 11/11, 3/15, 91.7% (22/24) and 1/14, respectively. NIPT-plus can safely and effectively detect fetal chromosomal abnormalities and can be extended to MMS screening, significantly reducing the proportion of interventional prenatal diagnoses, and those with positive screening still require further confirmation.

Tanshinone IIA potentiates the efficacy of imatinib by regulating the AKT-MDM2-P53 signaling pathway in Philadelphia chromosome-positive acute lymphoblastic leukemia

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is triggered by breakpoint cluster region-abelson leukemia virus (BCR/ABL) kinase. Targeting BCR/ABL kinase with tyrosine kinase inhibitors combined with chemotherapy is the standard first-line therapy for Ph+ ALL. Imatinib and dasatinib are the preferred agents for the treatment of Ph+ ALL. Dasatinib treatment can induce a faster and deeper remission than imatinib treatment; however, the side effects of dasatinib, especially the cardiovascular side effects, are markedly greater than those of imatinib. Patients will benefit from treatments that improve the efficacy of imatinib without increasing its side effects. The present study revealed that tanshinone IIA markedly potentiated the cytotoxic and apoptotic induction effects of imatinib by regulating the AKT-MDM2-P53 signaling pathway and inhibiting the anti-apoptotic proteins BCL2 and MCL1 apoptosis regulator, BCL2 family member in Ph+ ALL cell lines. In vitro studies, MTT assay, flow cytometry, western blotting and reverse transcription-quantitative PCR were performed in the present study to detect cell viability, cell apoptosis, protein expression and gene expression, respectively. In a Ph+ ALL mouse model, imatinib combined with tanshinone IIA also exhibited a synergistic effect on the reduction in leukemia burden without increasing the toxic side effects of imatinib. These results demonstrated that imatinib combined with tanshinone IIA might be a promising treatment strategy for patients with Ph+ ALL.

Single non-noble metal atom doped C2N catalysts for chemoselective hydrogenation of 3-nitrostyrene

Improving the reaction selectivity and activity for challenging substrates such as nitroaromatics bearing two reducible functional groups is important in industry, yet remains a great challenge using traditional metal nanoparticle based catalysts. In this study, single metal atom doped M-C₂N catalysts were theoretically screened for selective hydrogenation of 3-nitrostyrene to 3-vinylaniline with H₂ as the H-source. Among 20 M-C₂N catalysts, the non-noble Mn-C₂N catalyst was found to have excellent reaction selectivity. Importantly, due to the solid frustrated Lewis pair sites in the pores of Mn-C₂N, a low H₂ activation energy is achieved on high-spin Mn-C₂N and the rate-determining step for the hydrogenation reactions is the H diffusion from the metal site to the N site. The unraveled mechanism of the hydrogenation of 3-nitrostyrene using Mn-C₂N enriches the applications of Mn based catalysts and demonstrates its excellent properties for catalyzing the challenging hydrogenation reaction of substrates with two reducible functional groups.

[Effect of nuclear radiation on rat model of decompression sickness induced by large depth rapid floating escape]

Objective: To investigate the effects of different doses of nuclei exposure at different time on morbidity, mortality, and damage indicators in a rat model of decompression sickness caused by rapid flotation escape at a large depth. Methods: Eighty male SD rats were randomly divided into blank control group, escape control group and six intervention groups (escape at 4 hours after 4 Gy radiation, escape at 4 hours after 6 Gy radiation, escape at 4 hours after 12 Gy radiation, escape at 8 hours after 4 Gy radiation, escape at 8 hours after 6 Gy radiation, escape at 8 hours after 12 Gy radiation). Rats in intervention groups were exposed to different doses of γ-ray (4,6,12 Gy, respectively), and then were carried out a large depth and rapid buoyancy escape experiment (maximum pressure depth of 150 m). The changes of lung W/D, spleen index and plasma IL-1β levels were analyzed. Results: Compared with the blank control group, decompression sickness incidence and mortality of rats in escape groups after nuclear exposure were increased significantly. In 4 Gy and 6 Gy irradiation groups, higher morbidity and mortality were observed in rats which escaped at 4 h post nuclear exposure when compared with rats in 8 h groups. Consistent with the changes in morbidity and mortality, the wet / dry ratio of lung tissue, the pathological damage of lung tissue, and the decrease of spleen index showed the same trends: the changes were obvious at 4 h after lower doses nuclear radiation (4 Gy and 6 Gy), not at 8 h. However, these indicators all changed markedly at 4 and 8 h after higher doses nuclear radiation (12 Gy). Plasma IL-1β levels were significantly increased in each post-radiation exposure group when compared with the blank control group and the exposed control group. Conclusion: Nuclear radiation-induced lung injury, the damaged immune function and elevated plasma inflammatory factor concentrations increase the risk of decompression sickness after rapid ascent.

Neuroprotective Effect of Ganoderma lucidum Polysaccharides in an Epileptic Rat Model

We have previously shown the antiepileptic effects of Ganoderma lucidum polysaccharides in in vitro studies; however, so far there is no such study reported in an in vivo model. In this study, the status epilepticus was induced in rats by kainic acid injection followed by G. lucidum polysaccharides treatment once a day for 7 days. Their epileptic behavior, electroencephalograph, along with the expression of caveolin-1, brain derived neurotrophic factor, nuclear factor kappa B, and hippocampal neuronal survival were assessed. Results showed that the epileptic behavior was improved significantly after G. lucidum polysaccharides treatments by a significant reduction of both the epileptic score and the duration of a heavy seizure attack while increasing both the epileptic latency and the time to heavy seizure attack. The epileptic electroencephalograph was ameliorated from previous sharp waves and frequent high amplitudes spikes to a group of scattering waves with lower frequency and small spikes. Furthermore, G. lucidum polysaccharides treatments enhanced the expression of caveolin-1, brain derived neurotrophic factor, and survivin, but decreased nuclear factor kappa B expression. These changes indicate that G. lucidum polysaccharides can alleviate epileptic seizure and this neuroprotective effect may be via increasing the expression of caveolin-1, brain derived neurotrophic factor, and survivin and decreasing the expression of nuclear factor kappa B in the hippocampal neurons.

[Application of artificial intelligence-assisted diagnosis for cervical liquid-based thin-layer cytology]

Objective: To explore the application value of artificial intelligence-assisted diagnosis system for TBS report in cervical cancer screening. Methods: A total of 16 317 clinical samples and related data of cervical liquid-based thin-layer cell smears, which were obtained from July 2020 to September 2020, were collected from Southern Hospital, Guangzhou Huayin Medical Inspection Center, Shenzhen Bao'an People's Hospital(Group) and Changsha Yuan'an Biotechnology Co., Ltd. The TBS report artificial intelligence-assisted diagnosis system of cervical liquid-based thin-layer cytology jointly developed by Southern Medical University and Guangzhou F. Q. PATHOTECH Co., Ltd. based on deep learning convolution neural network was used to diagnose all clinical samples. The sensitivity,specificity and accuracy of both artificial intelligence-assisted diagnosis system and cytologists using artificial intelligence-assisted diagnosis system were analyzed based on the evaluation standard(2014 TBS). The time spent by the two methods was also compared. Results: The sensitivity of artificial intelligence-assisted diagnosis system in predicting cervical intraepithelial lesions and other lesions (including endometrial cells detected in women over 45 years old and infectious lesions) under different production methods, different cytoplasmic staining and different scanning instruments was 92.90% and 83.55% respectively, and the specificity of negative samples was 87.02%, while that of cytologists using artificial intelligence-assisted diagnosis system was 99.34%, 97.79% and 99.10%, respectively. Moreover, cytologists using artificial intelligence-assisted diagnosis system could save about 6 times of reading time than manual. Conclusions: Artificial intelligence-assisted diagnosis system for TBS report of cervical liquid-based thin-layer cytology has the advantages of high sensitivity, high specificity and strong generalization. Cytologists can significantly improve the accuracy and work efficiency of reading smears by using artificial intelligence-assisted diagnosis system.

Central Blockade of E-Prostanoid 3 Receptor Ameliorated Hypertension Partially by Attenuating Oxidative Stress and Inflammation in the Hypothalamic Paraventricular Nucleus of Spontaneously Hypertensive Rats

Hypertension, as one of the major risk factors for cardiovascular disease, significantly affects human health. Prostaglandin E2 (PGE2) and the E3-class prostanoid (EP3) receptor have previously been demonstrated to modulate blood pressure and hemodynamics in various animal models of hypertension. The PGE2-evoked pressor and biochemical responses can be blocked with the EP3 receptor antagonist, L-798106 (N-[(5-bromo-2methoxyphenyl)sulfonyl]-3-[2-(2-naphthalenylmethyl) phenyl]-2-propenamide). In the hypothalamic paraventricular nucleus (PVN), sympathetic excitation can be introduced by PGE2, which can activate EP3 receptors located in the PVN. In such a case, the central knockdown of EP3 receptor can be considered as a potential therapeutic modality for hypertension management. The present study examined the efficacy of the PVN infusion of L-798106, by performing experiments on spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). The rats were administered with chronic bilateral PVN infusion of L-798106 (10 μg/day) or the vehicle for 28 days. The results indicated that the SHRs had a higher mean arterial pressure (MAP), an increased Fra-like (Fra-LI) activity in the PVN, as well as a higher expression of gp91phox, mitogen-activated protein kinase (MAPK), and proinflammatory cytokines in the PVN compared with the WKYs. Additionally, the expression of Cu/Zn-SOD in the PVN of the SHRs was reduced compared with the WKYs. The bilateral PVN infusion of L-798106 significantly reduced MAP, as well as plasma norepinephrine (NE) levels in the SHRs. It also inhibited Fra-LI activity and reduced the expression of gp91phox, proinflammatory cytokines, and MAPK, whereas it increased the expression of Cu/Zn-SOD in the PVN of SHRs. In addition, L-798106 restored the balance of the neurotransmitters in the PVN. On the whole, the findings of the present study demonstrate that the PVN blockade of EP3 receptor can ameliorate hypertension and cardiac hypertrophy partially by attenuating ROS and proinflammatory cytokines, and modulating neurotransmitters in the PVN.

Multi-Scale Ecological Connectivity Dynamics Associated With Hydropower Station: A Case Study in the Lancang River Valley

Dam construction is a major threat to terrestrial ecological processes that exhibit spatial variation. As an effective indicator of species movements at large scales, the dynamics of forest landscape connectivity for the dispersal abilities of local species such as primates both upstream and downstream of the Manwan hydropower station were compared in three periods: before, during, and after dam construction (in 1974, 1988, and 2004, respectively). The equivalent connected area (ECA) index which was modified from the probability of connectivity (PC) index based on the graph theory was applied in this study. We used this method to analyze the spatial and temporal changes in the overall forest landscape connectivity due to dam construction. The results showed that forest connectivity decreased after dam construction. The forest connectivity upstream was much greater than that downstream in 1974 but was lower in 1988 and 2004. The importance of connectivity increased with increasing dispersal distance. Only 8, 12, and 18% of forest patches of small area exhibited changes in 1974, 1988, and 2004, respectively. Most of the large habitat patches (i.e., those with dECA values &gt;50%) remained stable, and the greatest patch changes were found at a dispersal distance of 400 m in all three periods. These large forest patch changes often occurred near the boundary of the study area. The Betweenness Centrality indicator, which identifies patches as stepping stones while accounting for ecological processes and biological flows at a larger scale, indicated that some habitat patches near Manwan Dam acted as stepping stones in maintaining the forest connectivity. Furthermore, rank correlations between the forest patch area and the three dPC (intra, flux, connector) fractions indicated that the dPCflux indicator can be used to measure the prioritization of habitat patches.

Changes in acid-base status in oxygen toxicity at 230 kPa oxygen as a function of exposure time

Breathing less than 50 kPa of oxygen over time can lead to pulmonary oxygen toxicity (POT). Vital capacity (VC) as the sole parameter for POT has its limitations. In this study we try to find out the changes of acid-base status in a POT rat model. Fifty male rats were randomly divided into five groups, exposed to 230 kPa oxygen for three, six, nine and 12 hours, respectively. Rats exposed to air were used as controls. After exposure the mortality and behavior of rats were observed. Arterial blood samples were collected for acid-base status detection and wet-dry (W/D) ratios of lung tissues were tested. Results showed that the acid-base status in rats exposed to 230 kPa oxygen presented a dynamic change. The primary status was in the compensatory period when primary respiratory acidosis was mixed with compensated metabolic alkalosis. Then the status changed to decompensated alkalosis and developed to decompensated acidosis in the end. pH, PCO2, HCO3-, TCO2, and BE values had two phases: an increase and a later decrease with increasing oxygen exposure time, while PaO2 and lung W/D ratio showed continuously increasing trends with the extension of oxygen exposure time. Lung W/D ratio was significantly associated with PaO2 (r = 0.6385, p = 0.002), while other parameters did not show a significant correlation. It is concluded that acid-base status in POT rats presents a dynamic change: in the compensatory period first, then turns to decompensated alkalosis and ends up with decompensated acidosis status. Blood gas analysis is a useful method to monitor the development of POT.

Fetal growth, fetal development, and placental features in women with polycystic ovary syndrome: analysis based on fetal and placental magnetic resonance imaging

OBJECTIVE

Polycystic ovary syndrome (PCOS), a common endocrine-metabolic dysfunction in reproductive-aged women, may be involved in compromised pregnancy and offspring outcomes. This study aimed to investigate whether maternal PCOS affects fetal growth, fetal development, and placental features.

METHODS

This retrospective case-control study included 60 pregnant women with PCOS (PCOS group) and 120 healthy pregnant women without PCOS (control group). Fetal magnetic resonance imaging (MRI) was performed followed by an ultrasound examination and indications for imaging, including known or suspected fetal pathology, history of fetal abnormality in previous pregnancy or in a family member, and concern for placenta accreta. Fetal MRI images were analyzed for head circumference (HC), abdomen circumference (AC), lung-to-liver signal intensity ratio (LLSIR, a prenatal marker of fetal lung maturity), lengths of liver and kidney diameters in fetuses, and placental relative signal intensity on T2-weighted single-shot fast spin echo (SSFSE) imaging (rSI_SSFSE), and placental relative apparent diffusion coefficient value (rADC). Data on height and weight of offspring were collected through telephone follow-up.

RESULTS

Compared to the control group, the PCOS group showed the following characteristics: (1) smaller biparietal diameter and femur length in fetuses (P=0.026 and P=0.005, respectively), (2) smaller HC in fetuses (evident after 32 weeks; P=0.044), (3) lower LLSIR and smaller dorsoventral length of liver in fetuses (evident before 32 weeks; P=0.005 and P=0.019, respectively), and (4) smaller placental thickness (evident before 32 weeks; P=0.017). No significant differences in placental rSI_SSFSE or rADC were observed between the groups (all P>0.05). No significant differences in height and weight of offspring during childhood existed between the groups (all P>0.05).

CONCLUSIONS

There exist alterations of fetal growth, fetal development, and placental features from women with PCOS.

[Effects of biological soil crusts on solute transport characteristics of sandy and loessal soils on the Loess Plateau, China]

Biological soil crusts (BSCs) greatly change surface soil structure and nutrient enrichment processes in arid and semiarid regions. However, their impacts on solute transport characteristics and nutrient loss are still not clear. In this study, the solute (Cl^- and Ca²⁺) transport experiments were conducted on soils covered by moss-dominated BSCs and uncrusted soil on sandy and loessal soils on the Loess Plateau, respectively. We analyzed the solute transport characteristics of the BSCs covered soil and uncrusted soil in different soil depths (0-5 cm and 5-10 cm). The BSCs mulching generated delay effects on the solute breakthrough process of 0-5 cm soils. The breakthrough time of Cl^- in the BSCs covered soil was 3.83 (sandy soil) and 2.09 times (loessal soil) longer than that in the uncrusted soil. The breakthrough time of Ca²⁺ in the BSCs covered soil was 2.50 and 2.73 times longer than that in the uncrusted soil. Due to the strong influence of BSCs mulching, the pore volume number of the complete solute breakthrough at 0-5 cm depth was higher than that at 5-10 cm depth in the BSCs covered soils. The breakthrough time of Cl^- at 0-5 cm depth was increased by 67.3% (sandy soil) and 51.8% (loessal soil) by the BSCs as compared with that at 5-10 cm depth. The breakthrough time of Ca²⁺ at 0-5 cm depth was increased by 8.0% and 33.7% by the BSCs. The BSCs reduced soil pore water flow velocity by 37.5%-70.2% compared with the uncrusted soil. Except for the sandy soil at 5-10 cm depth, the BSCs increased the solute dispersion coefficient by 1.73-6.29 times and the degree of dispersion by 2.77-20.95 times compared with the uncrusted soils. After the complete breakthrough of solute, the content of Ca²⁺ in the BSCs layer (0-2 cm) was 4.14 and 2.58 times higher than that in the uncrusted sandy and loessal soils, respectively. In conclusion, our results indicated that BSCs could reduce the deep percolation and loss of nutrients accumulated in surface soil through improving their solute adsorption and retention abilities, which is of great significance for the improvement of soil fertility and vegetation restoration on degraded land in arid and semiarid regions.

The evaluation of online course of Traditional Chinese Medicine for MBBS international students during the COVID-19 epidemic period

Background

During the COVID-19 epidemic period, Traditional Chinese Medicine (TCM) course for international students of Medical Bachelor, Bachelor of Surgery (MBBS) program in Zhejiang University has shifted from traditional classroom to online environment. This study aimed to investigate MBBS international students' perception on online TCM course, and to assess the online learning efficacy.

Methods

A total of 84 MBBS international students attending course of "Basic Traditional Chinese Medicine" during 2020 academic years at Zhejiang University were enrolled in this study. A quantitative questionnaire was respectively completed before and after the TCM course using a pretest-post-test design. By means of two online learning platforms, Learning in ZJU and DingTalk, TCM course was broadcast in both live and archived format to students.

Results

A total of 48 participants completed both baseline and follow-up questionnaires. The majority of participants preferred face-to-face classroom learning (26, 54.17% of total) when compared with online learning. Students felt that the course had brought in much benefits (mean 3.88, SD 0.87), and they were satisfied with the course content (mean 3.83, SD 0.95). Students' TCM related knowledge and their behaviors of discussion and consulting were significantly improved by online TCM course (all P < 0.001). Students' awareness of the necessity of TCM education and their feeling of difficulty in learning TCM were significantly strengthened (P = 0.042, 0.025, respectively).

Conclusion

Online learning is a good alternative for TCM course of MBBS international students when classroom learning is suspended, whereas it cannot replace the need for onsite and face-to-face learning.

Dityrosine suppresses the cytoprotective action of thyroid hormone T3 via inhibiting thyroid hormone receptor-mediated transcriptional activation

Dityrosine (Dityr) is the most common oxidized form of tyrosine. In the previous studies of mice treated with dityrosine, cell death in the pancreas, kidneys, and liver was detected in the presence of enhanced plasma triiodothyronine (T3) content. Due to its structural similarity with the thyroid hormone T3, we hypothesized that dityrosine might disrupt T3-dependent endocrine signaling. The cytotoxic effect of dityrosine was studied in C57BL/6 mice by gavage with a dityrosine dose of 320 μg per kg per day for 10 weeks. Cell death in the liver was detected in the presence of enhanced plasma thyroid hormone content in mice treated with dityrosine. The antagonistic effect of dityrosine on T3 biofunction was studied using HepG2 cells. Dityrosine incubation reduced T3 transport ability and attenuated the T3-mediated cell survival via regulation of the PI3k/Akt/MAPK pathway. Furthermore, dityrosine inhibited T3 binding to thyroid hormone receptors (TRs) and suppressed the TR-mediated transcription. Dityrosine also downregulated the expressions of T3 action-related factors. Taken together, this study demonstrates that dityrosine inhibits T3-dependent cytoprotection by competitive inhibition, resulting in downstream gene suppression. Our findings offer insights into how dityrosine acts as an antagonist of T3. These findings shed new light on cellular processes underlying the energy metabolism disorder caused by dietary oxidized protein, thus contributing to a better understanding of the diet-health axis at a cellular level.

Plasmodium yoelii 17XL infection modified maturation and function of dendritic cells by skewing Tregs and amplificating Th17

Background

Emerging data has suggested that Tregs, Th17, Th1 and Th2 are correlated with early immune mechanisms by controlling Plasmodium infection. Plasmodium infection appeared to impair the antigen presentation and maturation of DCs, leading to attenuation of specific cellular immune response ultimately. Hence, in this study, we aim to evaluate the relevance between DCs and Tregs/Th17 populations in the process and outcomes of infection with Plasmodium yoelii 17XL (P.y17XL).

Methods

DCs detection/analysis dynamically was performed by Tregs depletion or Th17 neutralization in P.y17XL infected BALB/c mice via flow cytometry. Then the levels of cytokines production were detected using enzyme-linked mmunosorbent assay (ELISA).

Results

Our results indicated that Tregs depletion or Th17 neutralization in BALB/c mice infected with P.y17XL significantly up-regulated the percentages of mDC and pDC, increased the expressions of major histocompatibility complex (MHC) class II, CD80, CD86 on DCs and the levels of IL-10/IL-12 secreted by DCs, indicating that abnormal amplification of Tregs or Th17 may damage the maturation and function of DCs during the early stage of malaria infection. Interestingly, we also found that the abnormal amplification of Th17, as well as Tregs, could inhibit the maturation of DCs.

Conclusions

Tregs skewing or Th17 amplification during the early stage of malaria infection may inhibit the maturation and function of DCs by modifying the subsets of DCs, expressions of surface molecules on DCs and secretion mode of cytokines.

The relationship between elevated serum uric acid and arterial stiffness in a healthy population

OBJECTIVE

This study aims to investigate the relationship between serum uric acid and arterial stiffness in a healthy population.

METHODS

Among the 979 participants, baPWV was non-invasively measured, the circulating levels of uric acid were tested, and the uric acid polymorphisms (rs2231142 and rs11722228) were genotyped. Then, the Mendelian randomization method was employed to test the relationship between serum uric acid and arterial stiffness in a healthy population.

RESULTS

After adjusting for age, gender, antihypertensive medication, body mass index, waist-to-hip ratio, urea nitrogen, creatinine and diabetic mellitus, there was a significant allelic difference in uric acid levels for each genotype (P < 0.0001 for rs2231142; P = 0.007 for rs11722228). However, there were no differences on the potential confounders between the genotypes of rs2231142 and rs11722228 (P > 0.05). The baPWV was significantly associated with circulating levels of uric acid after adjusting for cardiovascular risk factors and other potential confounders (P = 0.002). However, neither the single polymorphism, nor the accumulation of culprit alleles was associated with baPWV (P = 0.92 for rs2231142; P = 0.60 for rs11722228; P for trend = 0.77 for the combined analysis of culprit alleles).

CONCLUSION

These results do not support the causal role of circulating levels of uric acid in the development of arterial stiffness.

The roles of histidine kinases in sensing host plant and cell-cell communication signal in a phytopathogenic bacterium

It has long been known that phytopathogenic bacteria react to plant-specific stimuli or environmental factors. However, how bacterial cells sense these environmental cues remains incompletely studied. Recently, three kinds of histidine kinases (HKs) were identified as receptors to perceive plant-associated or quorum-sensing signals. Among these kinases, HK VgrS detects iron depletion by binding to ferric iron via an ExxE motif, RpfC binds diffusible signal factor (DSF) by its N-terminal peptide and activates its autokinase activity through relaxation of autoinhibition, and PcrK specifically senses plant hormone-cytokinin and elicits bacterial responses to oxidative stress. These HKs are critical sensors that regulate the virulence of a Gram-negative bacterium, Xanthomonas campestris pv. campestris. Research progress on the signal perception of phytopathogenic bacterial HKs suggests that inter-kingdom signalling between host plants and pathogens controls pathogenesis and can be used as a potential molecular target to protect plants from bacterial diseases. This article is part of the theme issue 'Biotic signalling sheds light on smart pest management'.

Association between serum cartilage oligomeric matrix protein and coronary artery calcification in maintenance hemodialysis patients

BACKGROUND

Coronary artery calcification (CAC) is common in end-stage renal disease (ESRD) patients, and the extent of CAC is closely related to cardiovascular outcomes in ESRD patients. Cartilage oligomeric matrix protein (COMP), as a component of the vascular matrix, has been found to be an inhibitor of arterial calcification in basic studies. However, there is no clinical research on the correlation between COMP and CAC in maintenance hemodialysis (MHD) patients. The aim of this study was to explore the relationship between serum COMP levels and CAC and cardiovascular events in MHD patients.

METHODS

Serum COMP levels were compared between 54 MHD patients and 66 healthy people. MHD patients were then divided into three groups according to the tertiles of the concentration of COMP level and were followed up for major adverse cardiac events (MACEs), which were defined as a combined end point of new onset angina pectoris, nonfatal myocardial infarction, heart failure, coronary artery revascularization, hospitalization due to angina pectoris and all-cause deaths. The CAC score was calculated based on computed tomography scans.

RESULTS

The serum COMP level in MHD patients was significantly higher than that in the general population [984.23 (248.43-1902.61) ng/mL vs. 219.01 (97.26-821.92) ng/mL, P < 0.01]. Serum COMP levels were positively correlated with CAC (r = 0.313, P = 0.021) and serum parathyroid hormone in MHD patients (r = 0.359, P < 0.01). Linear regression suggested that after adjusting for age, fasting blood glucose (Glu) and glycosylated hemoglobin (HbAlc), CAC score was an independent predictor in the final model for COMP level (β = 0.424, t = 3.130, P < 0.01). The receiver operating characteristic (ROC) curve showed that COMP ≥ 994 mg/mL had 68.0% sensitivity and 72.4% specificity for the prediction of severe CAC [area under the curve (AUC): 0.674, P = 0.030, 95% CI: 0.526-0.882]. After a median follow-up of 16 months (8-24 months), there was no difference in the incidence rate of MACEs between the upper, middle and lower serum COMP groups.

CONCLUSIONS

Our study found that MHD patients have higher levels of circulating COMP than controls. The serum COMP level is positively correlated with CAC score and could be used as a biomarker of severe CAC in MHD patients. However, there is no obvious correlation between serum COMP levels and the incidence of cardiovascular events.

Mechanism and Kinetic Study of Reducing MoO3 to MoO2 with CO-15 vol % CO2 Mixed Gases

In the present paper, the reduction reaction of high-purity MoO₃ with CO-15 vol % CO₂ mixed gases in the temperature range of 901-948 K is investigated via the thermogravimetric analysis technology. The results show that reduction of MoO₃ to MoO₂ follows a three-step reaction process, viz., MoO₃ is first reduced into Mo₉O₂₆, followed by Mo₄O₁₁, and finally to MoO₂. The reaction sequences of MoO₃ → Mo₉O₂₆ → Mo₄O₁₁ → MoO₂ are proposed, which are quite different from those observed on reduction of MoO₃ by pure H₂ or CO gases. Pure Mo₉O₂₆ and Mo₄O₁₁ could be synthesized once suitable time was controlled. Rate-controlling steps for the reduction from MoO₃ to Mo₉O₂₆ and Mo₉O₂₆ to MoO₂ (include both Mo₉O₂₆ to Mo₄O₁₁ and Mo₄O₁₁ to MoO₂) are interfacial chemical reactions, with the activation energies of 318.326 and 112.047 kJ/mol, respectively. This study also discovers that the as-synthesized MoO₂ keeps the same platelet-shaped and smooth morphology as the MoO₃ raw material; however, its particles size gradually increased as the reaction proceeds due to the formation of low-melting-point eutectic and the sticking of different particles.

[Epidemiological characteristics and risk factors of Blastocystis hominis infection among patients with HIV/AIDS in Fuyang City Anhui Province]

OBJECTIVE

To investigate the prevalence and risk factors of Blastocystis hominis infections among patients with HIV/AIDS in Fuyang City, Anhui Province.

METHODS

A cross-sectional study was conducted in Fuyang City, Anhui Province in 2016. The demographic and socioeconomic status, and the lifestyle and production style were collected using a questionnaire survey. B. hominis DNA was detected in subjects'stool samples using a PCR assay, and the CD4+ T lymphocyte count and HIV viral load were measured in the subjects' blood samples. The risk factors of B. hominis infections among patients with HIV/AIDS were identified using univariate and multivariate logistic regression analyses.

RESULTS

A total of 398 HIV/AIDS patients were enrolled in this study, with a mean age of 49.3 years, a mean body weight of 55.9 kg and a mean height of 164.4 cm. The prevalence of B. hominis infection was 6.78% in the study subjects, and no gender- (χ² = 1.589, P = 0.207), education level- (χ² =0.508, P = 0.776), marital status- (χ² = 0.419, P = 0.811) or occupation-specific prevalence (χ² = 2.744, P = 0.615) was detected. Among the patients with HIV/AIDS, there were no significant differences in the age (t = 0.370, P = 0.712), height (t = 1.587, P =0.113), body weight (t = 0.516, P = 0.606), CD4⁺ T lymphocyte count (t = 1.187, P = 0.230) or HIV viral load (t = 0.193, P =0.496) between B. hominis-infected and uninfected individuals. Dinking non-tap water [OR = 6.554, 95% CI: (1.876 to 22.903)] and keeping dogs [OR = 5.895, 95% CI: (2.017 to 17.225)] were identified as risk factors for B. hominis infection in patients with HIV/AIDS.

CONCLUSIONS

The prevalence of B. hominis infection is high in HIV/AIDS patients, and drinking non-tap water and keeping dogs are risk factors for B. hominis infection among HIV/AIDS patients.

The effects of di(2-ethylhexyl) phthalate exposure in women with polycystic ovary syndrome undergoing in vitro fertilization

Objectives

Di(2-ethylhexyl) phthalate (DEHP) is a common endocrine-disrupting chemical, which has potential reproductive toxicity. This study aimed to explore the effects of DEHP exposure in women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization.

Methods

In this case-control study, DEHP levels in follicular fluid (FF) of women with PCOS (n = 56) and controls (n = 51) were measured. The in vitro effects of DEHP exposure on primary-cultured human granulosa cells (GCs) and a steroidogenic human granulosa-like tumor cell line (KGN cells) were analyzed.

Results

Concentrations of DEHP in FF were significantly higher in women with PCOS than in controls. The clinical pregnancy rate was significantly lower in women with PCOS with high levels of DEHP than in controls. The levels of androgens produced by human GCs were significantly increased following DEHP exposure. Compared with controls, DEHP-treated human GCs and KGN cells showed significantly lower viability, cell cycle arrest, higher apoptosis, and altered expression of apoptosis-related genes.

Conclusion

Women with PCOS are exposed to increased levels of DEHP in follicles, which may be associated with pregnancy loss following in vitro fertilization. DEHP may disrupt steroid production, balance in cellular proliferation, and apoptosis in human granulosa cells.

[Clinical observation of eye acupuncture combined with conventional acupuncture on dry eye syndrome with yin deficiency of liver and kidney]

OBJECTIVE

To verify the efficacy of eye acupuncture combined with conventional acupuncture in the treatment of dry eye syndrome with yin deficiency of liver and kidney.

METHODS

A total of 90 patients with dry eye syndrome with yin deficiency of liver and kidney were randomly divided into an eye acupuncture combination with conventional acupuncture group (eye acupuncture combination group), a conventional acupuncture group and a western medication group, 30 cases in each group. In the western medication group, sodium hyaluronate eye drops were used 3 times a day, each time 1-2 drops, 10 days as one course for 3 courses; conventional acupuncture was applied at Jingming (BL 1), Cuanzhu (BL 2), Chengqi (ST 1), Fengchi (GB 20), Hegu (LI 4), Sanyinjiao (SP 6), Zusanli (ST 36), Guangming (GB 37) in the conventional acupuncture group; on the basis of the treatment in the conventional acupuncture, eye acupuncture was added at Shangjiao, Gan (liver), Shen (kidney), Pi (spleen) in the eye acupuncture combination group. The treatment in the eye acupuncture combination group and the conventional acupuncture group were given once a day, 10 days as one course, and a total of 3 courses were needed. Subjective symptom score was performed before treatment and every 10 days during treatment. Ocular surface analyzer was used before and after treatment.

RESULTS

The subjective symptom scores in the three groups were lower than those before treatment (P<0.05). Compared with the conventional acupuncture group and the western medication group, the subjective symptom score after 30 d of treatment in the eye acupuncture combination group was decreased (P<0.05). After treatment, the tear film break up time (BUT) was prolonged and the tear meniscus height increased in the eye acupuncture combination group and the conventional acupuncture group (P<0.05). Compared with the conventional acupuncture group and the western medication group, the tear film break up time was prolonged and the tear meniscus height increased in the eye acupuncture combination group (P<0.05). Corneal staining were better in all three groups than that before treatment (P<0.05). The total effective rate was 93.3% (28/30) in the eye acupuncture combination group, was better than 86.7% (26/30) in the conventional acupuncture group and 73.3% (21/30) in the western medication group (P<0.05).

CONCLUSION

Eye acupuncture combined with conventional acupuncture can significantly improve the clinical symptoms of dry eye syndrome with yin deficiency of liver and kidney, increase the secretion of tears, prolong the break up time of tear film, and restore the integrity of corneal epithelium.

[Effects and mechanisms of grazing on key processes of soil nitrogen cycling in grassland: A review]

Grazing is one of the most important practices for humans to manage grassland ecosystems. The disturbances of feeding, trampling, resting and excreta returning by herbivores will change plant communities and soil nutrient cycling. With the intensification of human activities, the intensity and frequency of grazing were also increased, which would have important impacts on the key processes of soil nitrogen (N) cycling in grassland. Grazing mainly affects the migration and transformation of N in soils by changing soil physical properties, soil N pool size, as well as the composition and structure of soil microbial community. Generally, moderate grazing could enhance soil N mineralization and nitrification, accelerate soil N turnover, and facilitate plant N use. The effects of grazing on denitrification are closely related to the hydrothermal conditions and soil types. Current results on the effects of grazing intensity on various key processes of soil N cycling remain inconsistent, with underlying mechanism being not clear. Based on extensive review of literature, we summarized the research progresses and the underlying mechanisms of the effects of grazing on key processes of soil N cycling. Some deficiencies in current research were pointed out. Possible key topics in the future study were proposed to provide a reference for further understanding the impacts of grazing on soil N cycling in grasslands.