Biomineralization of heavy metals based on urea transport and hydrolysis within a new bacterial isolate, B. intermedia TSBOI.

A newly isolated ureolytic bacteria, Brucella intermedia TSBOI, exhibited microbially induced calcite precipitation (MICP) which is a promising technique for the remediation of heavy metals in polluted environments. Brucella intermedia TSBOI achieved 90-100% removal of 1 mmol/L Cu2+/Pb2+/Zn2+ within 72 h. A distinctive feature lies in B. intermedia TSBOI's capacity for the transport and hydrolysis of urea, considered to be critical for its strong urease activity. This study explored the mechanisms of this capacity at the genetic, molecular and protein levels through complete genome sequencing, molecular docking and enzymatic reaction kinetics. The results revealed that, for urea hydrolysis, B. intermedia TSBOI exhibited a comprehensive urease gene cluster, with the key gene ureC demonstrating an absolute expression level approximating to 4 × 104 copies/RNA ng under optimal conditions. Results also confirmed the strong spontaneous, energy-independent binding ability of it's urease to urea, with the lowest Gibbs free energy binding site linking to the three amino acids, alanine, asparagine and serine. The urea transport gene yut presented and expressed, with the absolute expression enhanced in response to increasing urea concentrations. The significant positive correlation between ureC/yut expression levels and urease activity provided a theoretical basis for B. intermedia TSBOI's heavy metal bioremediation potential. ENVIRONMENTAL IMPLICATION: Heavy metals (Cu, Pb and Zn) were studied in this study. Heavy metals are hazardous due to their toxicity, persistence, and ability to bioaccumulate in living organisms. They can cause severe health issues, harm ecosystems, and contaminate air, water, and soil. A novel ureolytic bacteria, Brucella intermedia TSBOI, exhibited microbially induced carbonate precipitation capability was isolated which removed 90-100% of 1 mmol/L Cu2+/Pb2+/Zn2+ within 72 h. Its advantages in urea hydrolysis and transport facilitate the remediation of actual heavy metal contaminated environments.

Mechanisms of microbial-driven changes in soil ecological stoichiometry around gold mines.

In this study, we used soils with different pollution and nutrient levels (non-polluted S1, highly polluted low-nutrient S2, and highly polluted high nutrient S3) around the gold mine tailing ponds, and combined with metabolic limitation modeling and macro-genomics approaches, aiming to investigate the relationship between soil microbial composition and soil eco-chemometrics characteristics under heavy metal stress. The results showed that heavy pollution resulted in reduced SOC, TN, microbial biomass, and with C- and P- acquisition (BG, CBH, ALP) as well as nitrogen limitation of soil microbial metabolism in soils (S2, S3). Further analysis by macrogenomics showed that heavy metal contamination led to an increase in α-microbial diversity and altered the composition of microbial communities in the soil. The cycling of C, N, and P nutrients was altered by affecting the relative abundance of Anaeromyxobacter, Steroidobacter, Bradyrhizobium, Acidobacterium, Limnochorda (predominantly in the Ascomycetes and Acidobacteria phyla), with the most pronounced effect on the composition of microorganisms synthesizing C-acquiring enzymes, and heavy metals and pH were the main influences on ecological stoichiometry. The results of this study are useful for understanding the sustainability of ecological remediation in heavy metal contaminated areas and for developing ecological restoration strategies.

Exploring the accumulation capacity of dominant plants based on soil heavy metals forms and assessing heavy metals contamination characteristics near gold tailings ponds.

Heavy metal contamination of soil commonly accompanies problems around gold mine tailings ponds. Fully investigating the distribution characteristics of heavy metals and the survival strategies of dominant plants in contaminated soils is crucial for effective pollution management and remediation. This study aims to investigate the contamination characteristics, sources of heavy metals (As, Cd, Pb, Hg, Cu, Zn, Cr, and Ni) in soils around gold mine tailings ponds areas (JHH and WZ) and to clarify the form distribution of heavy metals (As, Cd, Pb, Hg) in contaminated plots as well as their accumulation and translocation in native dominant plants. The results of the study showed that the concentrations of As, Pb, Cd, Cu, and Zn in soil exceeded the national limits at parts of the sampling sites in both study areas. The Nemerow pollution index showed that both study areas reached extreme high pollution levels. Spatial analysis showed that the main areas of contamination were concentrated around metallurgical plants and tailings ponds, with Cd exhibiting the most extensive area of contamination. In the JHH, As (74%), Cd (66%), Pb (77%), Zn (47%) were mainly from tailings releases, and Cu (52%) and Hg (51%) were mainly from gold ore smelting. In the WZ, As (42%), Cd (41%), Pb (73%), Cu (47%), and Zn (41%) were mainly from tailings releases. As, Cd, Pb, and Hg were mostly present in the residue state, and the proportion of water-soluble, ion-exchangeable, and carbonate-bound forms of Cd (19.93%) was significantly higher than that of other heavy metals. Artemisia L. and Amaranthus L. are the primary dominating plants, which exhibited superior accumulation of Cd compared to As, Pb, and Hg, and Artemisia L. demonstrated a robust translocation capacity for As, Pb, and Hg. Compared to the concentrations of other forms of soil heavy metals, the heavy metal content in Artemisia L correlates significantly better with the total soil heavy metal concentration. These results offer additional systematic data support and a deeper theoretical foundation to bolster pollution-control and ecological remediation efforts in mining areas.

Super resolution reconstruction of CT images based on multi-scale attention mechanism.

CT diagnosis has been widely used in clinic because of its special diagnostic value. The image resolution of CT imaging system is constrained by X-ray focus size, detector element spacing, reconstruction algorithm and other factors, which makes the generated CT image have some problems, such as low contrast, insufficient high-frequency information, poor perceptual quality and so on. To solve the above problems, a super-resolution reconstruction method of CT image based on multi-scale attention mechanism is proposed. First, use a 3 × 3 and a 1 × 1 convolution layer extracting shallow features. In order to better extract the high-frequency features of CT images and improve the image contrast, a multi-scale attention module is designed to adaptively detect the information of different scales, improve the expression ability of features, integrate the channel attention mechanism and spatial attention mechanism, and pay more attention to important information, retain more valuable information. Finally, sub-pixel convolution is used to improve the resolution of CT image and reconstruct high-resolution CT image. The experimental results show that this method can effectively improve the CT image contrast and suppress the noise. The peak signal-to-noise ratio and structural similarity of the reconstructed CT image are better than the comparison method, and has a good subjective visual effect.

mRNA-Seq reveals the quorum sensing system luxS gene contributes to the environmental fitness of Streptococcus suis type 2.

BACKGROUND: Streptococcus suis type 2 (SS2) is an important zoonotic pathogen. We have previously reported the structure of LuxS protein and found that the luxS gene is closely related to biofilm, virulence gene expression and drug resistance of SS2. However, the mechanism of luxS mediated SS2 stress response is unclear. Therefore, this experiment performed stress response to luxS mutant (ΔluxS) and complement strain (CΔluxS), overexpression strain (luxS+) and wild-type SS2 strain HA9801, and analyzed the differential phenotypes in combination with transcriptome data. RESULTS: The results indicate that the luxS gene deletion causes a wide range of phenotypic changes, including chain length. RNA sequencing identified 278 lx-regulated genes, of which 179 were up-regulated and 99 were down-regulated. Differential genes focus on bacterial growth, stress response, metabolic mechanisms and drug tolerance. Multiple mitotic genes were down-regulated; while the ABC transporter system genes, cobalamin /Fe3+-iron carrier ABC transporter ATPase and oxidative stress regulators were up-regulated. The inactivation of the luxS gene caused a significant reduction in the growth and survival in the acid (pH = 3.0, 4.0, 5.0) and iron (100 mM iron chelator 2,2'-dipyridyl) stress environments. However, the mutant strain ΔluxS showed increased antioxidant activity to H2O2 (58.8 mmol/L). CONCLUSIONS: The luxS gene in SS2 appears to play roles in iron metabolism and protective responses to acidic and oxidative environmental conditions.

Hypertension is a clinically important risk factor for critical illness and mortality in COVID-19: A meta-analysis.

AIMS: As reported, hypertension may play an important role in adverse outcomes of coronavirus disease-2019 (COVID-19), but it still had many confounding factors. The aim of this study was to explore whether hypertension is an independent risk factor for critical COVID-19 and mortality. DATA SYNTHESIS: The Medline, PubMed, Embase, and Web of Science databases were systematically searched until November 2020. Combined odds ratios (ORs) with their 95% confidence interval (CIs) were calculated by using random-effect models, and the effect of covariates was analyzed using the subgroup analysis and meta-regression analysis. A total of 24 observational studies with 99,918 COVID-19 patients were included in the meta-analysis. The proportions of hypertension in critical COVID-19 were 37% (95% CI: 0.27 -0.47) when compared with 18% (95% CI: 0.14 -0.23) of noncritical COVID-19 patients, in those who died were 46% (95%CI: 0.37 -0.55) when compared with 22% (95% CI: 0.16 -0.28) of survivors. Pooled results based on the adjusted OR showed that patients with hypertension had a 1.82-fold higher risk for critical COVID-19 (aOR: 1.82; 95% CI: 1.19 - 2.77; P = 0.005) and a 2.17-fold higher risk for COVID-19 mortality (aOR: 2.17; 95% CI: 1.67 - 2.82; P < 0.001). Subgroup analysis results showed that male patients had a higher risk of developing to the critical condition than female patients (OR: 3.04; 95%CI: 2.06 - 4.49; P < 0.001) and age >60 years was associated with a significantly increased risk of COVID-19 mortality (OR: 3.12; 95% CI: 1.93 - 5.05; P < 0.001). Meta-regression analysis results also showed that age (Coef. = 2.3×10-2, P = 0.048) had a significant influence on the association between hypertension and COVID-19 mortality. CONCLUSIONS: Evidence from this meta-analysis suggested that hypertension was independently associated with a significantly increased risk of critical COVID-19 and inhospital mortality of COVID-19.

Association of body mass index (BMI) with critical COVID-19 and in-hospital mortality: A dose-response meta-analysis.

BACKGROUND AND PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic presents an unprecedented health crisis to the entire world. As reported, the body mass index (BMI) may play an important role in COVID-19; however, this still remains unclear. The aim of this study was to explore the association between BMI and COVID-19 severity and mortality. METHODS: The Medline, PubMed, Embase and Web of science were systematically searched until August 2020. Random-effects models and dose-response meta-analysis were used to synthesize the results. Combined odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated, and the effect of covariates were analyzed using subgroup analysis and meta-regression analyses. RESULTS: A total of 16 observational studies involving 109,881 patients with COVID-19 were included in the meta-analysis. The pooled results showed that patients with a BMI ≥ 30 kg/m2 had a 2.35-fold risk (OR = 2.35, 95%CI = 1.64-3.38, P < 0.001) for critical COVID-19 and a 2.68-fold risk for COVID-19 mortality (OR = 2.68, 95%CI = 1.65-4.37, P < 0.001) compared with patients with a BMI <30 kg/m2. Subgroup analysis results showed that patients with obesity and age > 60 years was associated with a significantly increased risk of critical COVID-19 (OR = 3.11, 95%CI = 1.73-5.61, P < 0.001) and COVID-19 mortality (OR = 3.93, 95%CI = 2.18-7.09, P < 0.001). Meta-regression analysis results also showed that age had a significant influence on the association between BMI and COVID-19 mortality (Coef. = 0.036, P = 0.048). Random-effects dose-response meta-analysis showed a linear association between BMI and both critical COVID-19(Pnon-linearity = 0.242) and mortality (Pnon-linearity = 0.116). The risk of critical COVID-19 and mortality increased by 9%(OR = 1.09, 95%CI = 1.04-1.14, P < 0.001) and 6%(OR = 1.06, 95%CI = 1.02-1.10, P = 0.002) for each 1 kg/m2 increase in BMI, respectively. CONCLUSIONS: Evidence from this meta-analysis suggested that a linear dose-response association between BMI and both COVID-19 severity and mortality. Further, obesity (BMI ≥ 30 kg/m2) was associated with a significantly increased risk of critical COVID-19 and in-hospital mortality of COVID-19.

Chili Consumption and Risk of Gastric Cancer: A Meta-Analysis.

Chili peppers are loved by people all over the world and have been indispensable vegetable for three meals a day. However, reports about the association between chili consumption and gastric cancer (GC) risk have been conflicting. So, we carried out this meta-analysis to evaluate the effect of chili consumption on the risk of GC. Medline, PubMed, Web of science, Embase, Cochrane Library databases were systematically searched until May 2019. Heterogeneity among studies was examined using Q and I2 statistics. Combined odds ratio (OR) with their 95% confidence interval (CI) were calculated using a random- or fixed-effects model. All data were analyzed using STATA 15.1 software. 13 studies (3,095 cases and 4,761 controls) were included in the meta-analysis. A 1.96-fold increased risk of GC was shown for the moderate-high chili consumption (OR = 1.96, 95%CI =1.59-2.42). Dose-response analysis showed a significant nonlinear association of GC risk with capsaicin intake (pnon-linearity <0.05) and suggested a significant positive association between high chili consumption and GC risk (OR = 2.28, 95%CI = 1.76-2.96) but not moderate chili consumption (OR = 0.72, 95%CI = 0.36-1.41). Sensitivity analysis and publication bias test results indicated that no publication bias and the results were reliable (Egger's: P = 0.288). Evidence from this meta-analysis suggested that a higher level of chili consumption may be associated with an increased incidence of GC. More studies are warranted to confirm the association between chili consumption and the risk of GC.

Effect of coffee consumption on dyslipidemia: A meta-analysis of randomized controlled trials.

BACKGROUND AND AIM: Dyslipidemia is a common metabolic disease worldwide and also an important predisposing factor for cardiovascular diseases (CVDs). Coffee is loved by people all over the world; however, the association between coffee consumption and blood lipids has yielded inconsistent results. So we carried this meta-analysis to explore the effects of coffee consumption on blood lipids. METHODS AND RESULTS: Medline, PubMed, Web of science, Embase, and Cochrane Library databases were systematically searched until April 2020. Combined weighted mean differences (WMD) with their 95% confidence interval (CI) were calculated using random-effects models, and between-study heterogeneity was assessed by Cochran's Q test and I2 statistics. Subgroup analysis and meta-regression analysis were also conducted to explore the potential heterogeneity. A total of 12 RCT studies involving the association between coffee consumption and blood lipid levels were included in the meta-analysis. The pooled results showed that coffee consumption significantly increased total cholesterol (TC) (WMD: 0.21 mmol/L, 95% CI: 0.04; 0.39, P = 0.017), triglyceride (TG) (WMD: 0.12 mmol/L, 95% CI: 0.03; 0.20, P = 0.006) and low-density lipoprotein (LDL-C) (WMD: 0.14 mmol/L, 95% CI: 0.05; 0.24, P = 0.003) while had no significant effect on high-density lipoprotein (HDL-C) (WMD: -0.01 mmol/L, 95% CI: -0.06; 0.04, P = 0.707). Dose-response analysis results revealed significant positive nonlinear associations between coffee consumption and the increase in TC, LDL-C, and TG levels. CONCLUSIONS: Evidence from this meta-analysis suggested that coffee consumption may be associated with an elevated risk for dyslipidemia and CVDs. So a reasonable habit of coffee consumption (<3 cups/d) is essential for the prevention of dyslipidemia.

[Regulation of Chrysophanol-mediated TLR4/NF-κB Pathway on Renal Injury and Immune Response in IgA Nephropathy Rats].

OBJECTIVE: To investigate the regulatory effect and its mechanism of chrysophanol (CP) on renal injury and immune response in immunoglobin A (IgA) nephropathy rats. METHODS: IgA nephropathy rat model was established by the method of lipopolysaccharide + bovine serum protein + carbon tetrachloride. Then the rats were randomly divided into 5 groups: control group, IgA group, IgA+low, medium and high dose of CP groups(2.5, 5 and 10 mg/kg for each group respectively). IgA+CP groups were intraperitoneally injected with different doses of chrysophanol once a day for 4 weeks, and the control group and IgA group were given isovolumetric saline. Urine protein content, serum creatinine and urea nitrogen were detected at 24 h after the administration of drugs. Kidney histopathological damage and apoptosis were measured by HE and TUNEL staining. The expression levels of Caspase-3 and Caspase-9 were detected by RT-PCR and Western blot; The contents of malondialdehyde (MDA), superoxide dismutase (SOD) and (glutathione peroxidase, Gpx) were detected by enzyme-linked immunosorbent assay (ELISA). The expression of interleukin-1ß, -6 (IL-1ß, IL-6) and tumor necrosis factor (TNF-α) in serum and kidney tissue were measured by ELISA and Western blot, respectively. The mRNA and protein expression levels of toll-like receptro 4 (TLR4), nuclear factor-κB P65 (NF-κB P65) were also detected by RT-PCR and Western blot, and vascular cell adherin molecule (VCAM-1) protein level was deteted by Western blot. RESULTS: In IgA nephropathy rats, the administration of CP reduced proteinuria, serum creatinine and urea nitrogen in a dose-dependent manner (P < 0.01). It also improved the pathological damage of kidney tissue, reduced the apoptosis rate (P < 0.01), and decreased the mRNA and protein expression levels of apoptosis-related proteins Caspase-3 and Caspase-9 (P < 0.01). CP inhibited MDA production while increased the activities of antioxidant enzymes Gpx and SOD (P < 0.01), and decreased the levels of serum and protein expression of IL-1ß, IL-6 and TNF-α (P < 0.01), as well as the expression levels of TLR4, NF-κB P65 and VCAM-1 (P < 0.01). CONCLUSION: Chrysophanol could play a protective role in IgA nephropathy rats, and its mechanism may be related to alleviating kidney injury and regulating immune response.

[Effects of cultural factors on yield of Linum usitatissimum (Tianya 9)].

Cultural factors influencing high yield and good quality Linum usitatissimum (Tianya 9) were investigated. The correlations between these factors and its yield were analyzed. Path coefficient and principal component analysis were conducted, adopting uniform design of the 8 cultivating factors, i.e. planting density (X1), base nitrogen quantity (X2), base phosphorus quantity (X3), base potassium quantity (X4), foliar fertilizer (potassium dihydrogen phosphate, X5), foliar fertilizer (boron fertilizer, X6), growth regulator (multi-effect azole, X7) and growth duration irrigation amount (X8), aiming at exploring better cultivating plan of L. usitatissimum for Gansu Province. The results indicated that the factors influencing the yield of L. usitatissimum were X1, X7, X2, X3, X5 and X4 in a descending order. Simulation and optimization of the highest yield was further implemented. Frequency analysis showed that the cultivating factors resulting in yield higher than 173.58 kg . hm-2 were 4. 68 - 4. 92 kg . hm-2 (X1) , 11. 59 - 14. 75 kg . hm-2 (X2), 17.26- 21.95 kg . hm-2 (X3), 7.00-12.50 kg . hm-2 (X4) , 1.41-1.81 kg . hm-2 (X5) and 751.74- 954.04 g . hm-2 (X7).