The dissolution characteristics of cadmium containing birnessite produced from paddy crusts.

The cadmium (Cd) accumulates in birnessite as it forms on the surface of paddy crusts (PC). The stability of Cd-containing birnessite is influenced by environmental factors, and destabilized birnessite releases dissolved Cd. We report the effects of pH, oxalic acid, and light on the dissolution of Cd-containing birnessite. We found that at pH 4.0, with light and 0.20 mol/L oxalic acid, the ratio of dissolved Cd and manganese (Mn) peaked after 24 h at 2978.0 µg/g and 326.8 mg/g, respectively. The three environmental factors affected the dissolution of Cd-containing birnessite in the following order: pH > oxalic acid > light. During dissolution process, Cd and Mn did not dissolve simultaneously, and the dissolved Cd/Mn ratio in the solution was significantly lower than that of the pristine mineral (33.5 × 10-3). Compared with Mn, Cd dissolution was inhibited by strong acidity (pH 4.0-5.0), and the dissolved Cd/Mn ratio was 5-10 × 10-3. Mild acidity (pH 6.0) was weakly inhibitory, with a Cd/Mn ratio of 6-15 × 10-3. In an alkaline (pH 8.0) oxalate environment, light illumination inhibited Cd dissolution, and the Cd/Mn ratio decreased over time due to the stability of the products formed by oxalate and carbonate, with Cd being more stable than those formed by Mn. Our findings would provide insights into the migration and transformation of PC-associated Cd in paddy fields.

Application of biological soil crusts for efficient cadmium removal from acidic mine wastewater.

Utilizing an acid-resistant biological soil crust (BSC) species that we discovered, we developed a device capable of efficiently removing cadmium (Cd) from mine wastewater with varying levels of acidity. Our research has demonstrated that this particular BSC species adapts to acidic environments by regulating the balance of fatty acids and acid-resistant enzymes. At a Cd concentration of 5 mg/L, the BSC grew well. When the initial Cd concentration was 2 mg/L, and the flow rate was set at 1 mL/min (at pH levels of 3, 4, and 5), BSC had a high removal rate of Cd, and the removal rate increased with the increase of pH (from 90% to 97%). Chemisorption is the primary removal mechanism in the initial stage, where the functional groups and minerals on the surface of the BSC play a significant role. In addition, BSC also adapts to Cd stress by changing bacterial community structure. It was discovered through infrared spectroscopy and two-dimensional correlation analysis that hydrophilic groups, specifically phosphate and carboxyl groups, exhibited the highest reactivity during the Cd binding process. Protein secondary structure analysis confirmed that as the pH increased, the adsorption capacity of the BSC increased; making biofilm formation easier. This study presents a novel approach for the treatment of acidic wastewater.

Fertilizer-induced manganese oxide formation enhances cadmium removal by paddy crusts from irrigation water.

Fertilization is a crucial agrological measure for agricultural production that can significantly impact the removal of Cd from irrigation water by paddy crusts (PC). In this study, laboratory and field experiments were conducted to investigate the impact of fertilization at low, medium, and high concentrations on the accumulation of Cadmium (Cd) in PC and the underlying mechanisms involved. The results showed that only low fertilizer concentration could promote the removal of Cd by PC, which reduced the Cd concentration in irrigation water from 19.52 µg/L to 5.35 µg/L. Conversely, medium and high fertilizer concentrations reduced the accumulation of Cd by PC. After fertilizer addition, the proportion of Fe-Mn oxidizable-Cd in PC reached 55 % (with low concentration of fertilizer treatment). The application of low concentration of fertilizer was found to stimulate the growth of filamentous green algae, leading to a significant increase in the relative abundance of sphingomonadaceae (by 1.39 %) and comamonadaceae (by 1.29 %). The XRD, SEM and correlation analysis show that a large amount of manganese oxide is formed on the surface of PC, which increases the fixation of Cd. These findings provide a new perspective for the remediation of heavy metal contamination in paddy fields.

Cadmium accumulation in rice grains is mitigated by duckweed-like hydrophyte through adsorption and increased ammonia nitrogen.

Although increasing attention has been paid to agronomic measures for reducing the heavy metal load in rice grain, the effects of duckweed-paddy co-cropping technology on the accumulation of cadmium (Cd) in rice grains remain unclear. To investigate its specific effects on Cd accumulation in paddy fields, three types of duckweed-like hydrophyte (DH), Azolla imbricata, Spirodela polyrrhiza, and Lemna minor were chosen for study. Their use resulted in a reduction of Cd content in rice grains from 0.40 mg/kg to <0.20 mg/kg, with A. imbricata yielding the best results (0.15 mg/kg). The three types of DH reduced the available Cd content in the soil by 10 % to 35 % after the paddy tillering stage. The reduction of available Cd content was attributed to the absorption, high pH, and increase of relative abundance of special bacteria of immobilizing Cd. In addition, DH could regulate soil nitrogen leading to ammonium nitrogen increased from 75 mg/kg to 100 mg/kg, while nitrate nitrogen decreased from 0.55 to 0.1-0.3 mg/kg. The increase of ammonium nitrogen content might induce the low Cd transfer ability in rice plant and then low Cd content in rice grain. This study demonstrated that DH has a good effect on the reduction of the Cd concentration in rice grains. Consequently, duckweed-paddy co-cropping technology offers a potential solution to heavy metal pollution and agricultural non-point source pollution, as it not only reduces Cd levels in rice plants, but also fixes nitrogen, reducing the need for nitrogen application.

Biochemical and Structural Analyses Shed Light on the Mechanisms of RadD DNA Binding and Its ATPase from Escherichia coli.

DNA double-strand breaks (DSBs) are the most perilous and harmful type of DNA damage and can cause tumorigenesis or cell death if left repaired with an error or unrepaired. RadD, a member of the SF2 family, is a recently discovered DNA repair protein involved in the repair of DSBs after radiation or chemical damage. However, the function of RadD in DNA repair remains unclear. Here, we determined the crystal structures of RadD/ATPγS and RadD/ATP complexes and revealed the novel mechanism of RadD binding to DNA and ATP hydrolysis with biochemical data. In the RadD catalytic center, the Gly34 and Gly36 on the P-loop are key residues for ATP binding besides the conserved amino acids Lys37 and Arg343 in the SF2 family. If any of them mutate, then RadD loses ATPase activity. Asp117 polarizes the attacking water molecule, which then starts a nucleophilic reaction toward γ-phosphate, forming the transition state. Lys68 acts as a pocket switch to regulate substrate entry and product release. We revealed that the C-terminal peptide of single-stranded DNA-binding protein (SSB) binds the RadD C-terminal domain (CTD) and promotes the RadD ATPase activity. Our mutagenesis studies confirmed that the residues Arg428 on the zinc finger domain (ZFD) and Lys488 on the CTD of RadD are the key sites for binding branched DNA. Using the Coot software combined with molecular docking, we propose a RadD-binding DNA model for the DNA damage repair process.

Effects of a Virtual Reality-Based Meditation Intervention on Anxiety and Depression Among Patients With Acute Leukemia During Induction Chemotherapy: A Randomized Controlled Trial.

BACKGROUND: Emerging evidence supports that virtual reality (VR)-based meditation interventions may improve anxiety and depression among patients with cancer. However, empirical studies involving patients with acute leukemia during induction chemotherapy are limited. OBJECTIVE: This study aimed to examine the effects of VR-based meditation intervention on alleviating anxiety and depression and improving the quality of life among patients with acute leukemia during induction chemotherapy. METHODS: This randomized controlled trial recruited 63 patients newly diagnosed with acute leukemia. Participants were randomly assigned to an intervention group (received VR-based meditation for 20 min daily for 14 days) and a control group. Anxiety, depression, and quality of life were measured using the State Anxiety Inventory, the Center for Epidemiological Studies Depression Scale, and the Functional Assessment of Cancer Therapy-Leukemia Questionnaire, respectively. All outcomes were measured at baseline and post-intervention. RESULTS: Compared with patients in the control group, those in the intervention group demonstrated a significantly greater reduction in anxiety (P = .04) and improvement in quality of life (P = .04). However, no significant difference was noted in depression levels between groups (P = .09), although a decreasing trend was observed in the intervention group. CONCLUSION: Virtual reality-based meditation intervention effectively alleviated anxiety and improved the quality of life among acute leukemia patients during induction chemotherapy. Future randomized controlled trials with larger sample sizes and longer follow-up periods are warranted. IMPLICATION FOR PRACTICE: Virtual reality-based meditation can be applied in clinical practice virtually anytime and anywhere to provide a convenient intervention for anxiety reduction for acute leukemia patients during induction chemotherapy.

Single-cell RNA-seq reveals interferon-induced guanylate-binding proteins are linked with sarcopenia.

BACKGROUND: Sarcopenia is defined as an age-related progressive loss of muscle mass and/or strength. Although different factors can contribute to this disease, the underlying mechanisms remain unclear. We assessed transcriptional heterogeneity in skeletal muscles from sarcopenic and control mice at single-cell resolution. METHODS: A mouse model was established to study sarcopenic skeletal muscles. Single-cell RNA-seq was performed on tibialis anterior (TA) muscle cells collected from sarcopenic and control mice. A series of bioinformatic analyses were carried out to identify and compare different cell types under different conditions. Immunofluorescence staining and western blotting were used to validate the findings from single-cell experiments. Tube formation assays were conducted to further evaluate the effects of Gbp2 on endothelial cells during angiogenesis. RESULTS: A murine sarcopenia model was successfully established using a senescence-accelerated mouse strain (SAMP6, n = 5). Sarcopenia phenotype was induced by administration of dexamethasone (20 mg/kg) and reduced physical activity. Senescence-resistant mice strain (SAMR1) and SAMP6 strain with similar activity but injected with PBS were recruited as two control groups. As signs of sarcopenia, body weight, muscle cell counts and cross-sectional fibre area were all significantly decreased in sarcopenic mice (P value = 0.004, 0.03 and 0.035, respectively). After quality control, 13 612 TA muscle single-cell transcriptomes were retained for analysis. Fourteen cell clusters were identified from the profiled cells. Among them, two distinct endothelial subtypes were found to be dominant in the sarcopenia group (42.2% cells) and in the two control groups (59.1% and 47.9% cells), respectively. 191 differentially expressed genes were detected between the two endothelial subtypes. Sarcopenia-specific endothelial cell subtype exhibited a dramatic increase in the interferon family genes and the interferon-inducible guanylate-binding protein (GBP) family gene expressions. For example, Igtp and Gbp2 in sarcopenic endothelial cells were 5.4 and 13.3 times higher than those in the control groups, respectively. We further validated our findings in muscle specimens of sarcopenia patients and observed that GBP2 levels were increased in endothelial cells of a subset of patients (11 of 40 patients, 27.5%), and we identified significantly higher CD31 and GBP2 co-localization (P value = 0.001128). Finally, we overexpressed Gbp2 in human umbilical vein endothelial cells in vitro. The endothelial cells with elevated Gbp2 expression displayed compromised tube formation. CONCLUSIONS: Our single-cell-based results suggested that endothelial cells may play critical roles in sarcopenia development through interferon-GBP signalling pathways, highlighting new therapeutic directions to slow down or even reverse age-related sarcopenia.

Intervertebral disc injury is the mainspring for the postoperative increase in Cobb Angle after thoracolumbar burst fracture.

STUDY DESIGN: A single-institution retrospective study of a cohort of patients who underwent internal fixation spine surgery for thoracolumbar burst fracture (TLBF). OBJECTIVE: To observe the imaging manifestations of intervertebral disc changes in TLBF, to analyze the relationship between the degree of disc injury and the Cobb angle increase. METHODS: We retrospectively analyzed the data of patients who underwent short-segment pedicle screw instrumentation in the spinal surgery department of a single hospital between January 2014 and December 2017 (n = 90). According to the magnetic resonance imaging characteristics of the superior intervertebral disc tissue of the injured vertebrae before the operation, the intervertebral disc injury was divided into three types, which was used for group allocation: group A, uninjured intervertebral disc group; group B, mild intervertebral disc injury group; and group C, severe intervertebral disc injury group. The main imaging results of the three groups Cobb, IVA, IHI, AHIV, and VAS were compared among groups. RESULTS: Ninety patients were included in the study (n = 38, 32, and 20, in groups A, B, and C, respectively). There was no statistically significant difference in demographics among the three groups (p > .05). 1-year post-surgery, the Cobb angle in group C differed significantly from that in groups A and B (p < .01). There was a significant difference in Cobb angle between groups A and B after internal fixation was removed for 6 months. At 1-year post-surgery, the IHI group C differed significantly from groups A and B (p < .01), while groups A and B were similar (p = .102); however, at 6 months after the internal fixation was removed, the IHI differed significantly between these two groups, also the AHIV between groups A and B was statistically significant (p < .01). The VAS pain score was similar among the three groups. Pearson's test showed that the increase in the Cobb angle was moderately correlated with IVA and IHI, and weakly correlated with AHIV. CONCLUSION: For TLBF with an intervertebral disc injury, the presurgical degree of intervertebral disc injury is the main reason for the post-surgery increase in the Cobb angle. Thus, diagnosis and treatment of this kind of patient require attention to the risk of spinal deformity.

The application of topical vancomycin powder for the prevention of surgical site infections in primary total hip and knee arthroplasty: A meta-analysis.

BACKGROUND: Surgical site infections (SSIs), particularly periprosthetic joint infections (PJI), following a primary total joint arthroplasty (TJA) impose a major burden by increasing morbidity, mortality, disability rate, and health expenditure. Surgeons are increasingly using topical vancomycin powder as a preventative measure, but the effectiveness of this method has been debated in TJA. Thus, we designed a meta-analysis to compare the outcomes after primary TJA between a group treated with topical vancomycin powder and an untreated control group aiming to answer: (1) whether the application of topical vancomycin powder can reduce the infection rate after primary total joint replacement; (2) are the main types of pathogens causing SSIs after the application of topical vancomycin powder different from those of patients not using topical vancomycin? MATERIALS AND METHODS: A meta-analysis was conducted in accordance with the PRISMA guidelines. We included retrospective cohort studies and prospective randomized controlled trials of patients who underwent primary total joint arthroplasty with and without vancomycin powder application before wound closure and reported the SSI rates. The English literature in the PubMed (MEDLINE), EMBASE, Web of Science, and the Cochrane Library databases was comprehensively searched. Literature search, data extraction, and quality assessment were conducted by 2 authors. The main outcomes were SSI and PJI rates, and the secondary outcome was the bacterial spectrum. Statistical analyses were performed with the Review Manager (RevMan) Version 5.3. RESULTS: Six retrospective cohort studies and 3 prospective cohort studies with 4512 participants were included (2354 in vancomycin group and 2158 in the control group). In the TJA group, the vancomycin powder-treatment resulted in a significantly lower proportion of patients with SSIs (relative risk [RR]=0.40, 95% confidence interval [CI]=0.27-0.61 [p<0.001]) or PJI (RR=0.37, 95% CI=0.23-0.60 (p<0.001)). In the total hip arthroplasty group, the vancomycin powder treatment decreased the rate of SSIs and PJI by 66% (RR=0.34, 95% CI=0.15-0.78 [p=0.01]) and 74% (RR=0.26, 95% CI=0.10-0.67 (p=0.005)), respectively. In the total knee arthroplasty group, the vancomycin powder decreased the rate of SSIs and PJI by 67% (RR=0.43, 95% CI=0.26-0.70 [p<0.001]) and 66% (RR=0.44, 95% CI=0.25-0.77 [p=0.004]) respectively. Staphylococcus aureus (or methicillin-sensitiveStaphylococcus aureus) (6 in vancomycin group versus 11 in control group) was the most common pathogenic bacteria, followed by Staphylococcus epidermidis (1 in vancomycin group versus 2 in control group) and methicillin-resistant Staphylococcus aureus (2 in vancomycin group versus 4 in control group). Pseudomonas aeruginosa was the main gram-negative pathogen, with 3 cases in the control group and 1 case in the vancomycin powder-treatment group. DISCUSSION: The local application of vancomycin powder could significantly decrease the rate of SSIs and PJI in primary TJA without modifying the spectrum of bacteria involved. We recommend topical administration of the vancomycin powder before wound closure after a full evaluation of the patients. LEVEL OF EVIDENCE: III; meta-analysis.

Crystal structure of a novel ATPase RadD from Escherichia coli.

The helicase superfamily 2 (SF2) proteins are involved in essentially every step in DNA and RNA metabolism. The radD (yejH) gene, which belongs to SF2, plays an important role in DNA repair. The RadD protein includes all seven conserved SF2 motifs and has shown ATPase activity. Here, we first reported the structure of RadD from Escherichia coli containing two RecA-like domains, a zinc finger motif, and a C-terminal domain. Based on the structure of RadD and other SF2 proteins, we then built a model of the RedD-ATP complex.

Crystal structure of the N-terminal domain of human CDC73 and its implications for the hyperparathyroidism-jaw tumor (HPT-JT) syndrome.

CDC73/Parafibromin is a critical component of the Paf1 complex (PAF1C), which is involved in transcriptional elongation and histone modifications. Mutations of the human CDC73/HRPT2 gene are associated with hyperparathyroidism-jaw tumor (HPT-JT) syndrome, an autosomal dominant disorder. CDC73/parafibromin was initially recognized as a tumor suppressor by inhibiting cell proliferation via repression of cyclin D1 and c-myc genes. In recent years, it has also shown oncogenic features by activating the canonical Wnt/ß-catenin signal pathway. Here, through limited proteolysis analysis, we demonstrate that the evolutionarily conserved human CDC73 N-terminal 111 residues form a globularly folded domain (hCDC73-NTD). We have determined a crystal structure of hCDC73-NTD at 1.02 Å resolution, which reveals a novel protein fold. CDC73-NTD contains an extended hydrophobic groove on its surface that may be important for its function. Most pathogenic CDC73 missense mutations associated with the HPT-JT syndrome are located in the region encoding CDC73-NTD. Our crystal and biochemical data indicate that most CDC73 missense mutations disrupt the folding of the hydrophobic core of hCDC73-NTD, while others such as the K34Q mutant reduce its thermostability. Overall, our results provide a solid structural basis for understanding the structure and function of CDC73 and its association with the HPT-JT syndrome and other diseases.

Interactive effects of cadmium and Microcystis aeruginosa (cyanobacterium) on the growth, antioxidative responses and accumulation of cadmium and microcystins in rice seedlings.

Cadmium pollution and harmful cyanobacterial blooms are two prominent environmental problems. The interactive effects of cadmium(II) and harmful cyanobacteria on rice seedlings remain unknown. In order to elucidate this issue, the interactive effects of cadmium(II) and Microcystis aeruginosa FACHB905 on the growth and antioxidant responses of rice seedling were investigated in this study, as well as the accumulation of cadmium(II) and microcystins. The results showed that the growth of rice seedlings was inhibited by cadmium(II) stress but promoted by inoculation of M. aeruginosa FACHB905. cadmium(II) stress induced oxidative damage on rice seedlings. Inoculation of M. aeruginosa FACHB905 alleviated the toxicity of cadmium(II) on rice seedlings. The accumulation of cadmium(II) in rice seedlings was decreased by M. aeruginosa FACHB905, but the translocation of cadmium(II) from root to shoot was increased by this cyanobacterium. The accumulation of microcystins in rice seedlings was decreased by cadmium(II). Results presented in this study indicated that cadmium(II) and M. aeruginosa had antagonistic toxicity on rice seedlings. The findings of this study throw new light on evaluation of ecological- and public health-risks for the co-contamination of cadmium(II) and harmful cyanobacteria.

Effects of bloom-forming cyanobacterial extracellular polymeric substances on the adsorption of cadmium onto kaolinite: behaviors and possible mechanisms.

Cyanobacterial blooms result in high level of cyanobacterial extracellular polymeric substances (EPS) in water. The effects of bloom-forming cyanobacterial EPS on the distribution of Cd(II) in the interface between sediment and water is unknown. Clay is a main component in sediment. The effects of EPS, originated from a typical bloom-forming cyanobacterium Microcystis aeruginosa, on the adsorption and desorption characteristics of Cd(II) by kaolinite were investigated in this study. Results of XRD analysis indicated that cyanobacterial EPS bound on the surface of kaolinite. The composite of kaolinite + EPS showed higher adsorption capacity toward Cd(II) than pure kaolinite, and hydroxyl groups were involved in the adsorption processes. The data for the adsorption of Cd(II) by kaolinite are well fitted by both Langmuir model and Freundlich model, whereas only Freundlich model well describes the adsorption data of Cd(II) by the composite of kaolinite + EPS. The adsorption of Cd(II) onto kaolinite was an exothermic process, but it became an endothermic process after EPS incorporation. Results of desorption showed that EPS incorporation increased the adsorption of kaolinite toward Cd(II) through physical adsorption, ion exchange and complexation.