Fusion rate and complications of oblique lumbar interbody fusion and transforaminal lumbar interbody fusion in the treatment of lumbar degenerative diseases: a meta-analysis.

Background: There currently exists some controversy about the efficacy of oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar degenerative diseases. Aim: This study compares the application effects of OLIF and TLIF in lumbar degenerative diseases by reviewing the literature and using meta-analysis. Methods: We included randomized controlled trials and cohort studies comparing TLIF and OLIF in the treatment of lumbar degenerative diseases. We searched for words such as "intervertebral disc degeneration," "spinal fusion," and "lumbar vertebrae" in the PubMed, Embase, and Cochrane Library databases. The search date was set from the establishment date of the database to October 2023. Two authors independently conducted document screening, data abstraction, and qualitative assessment. A meta-analysis was performed and adapted to RevMan5.3 software. The odds ratio (OR), weighted mean difference (WMD), and 95% CI were calculated by adopting a fixed-effect model (FEM) or a random-effect model (REM). Results: A total of 18 cohort studies were included with 1,550 patients, of whom 806 patients underwent TLIF (TLIF group) and 744 patients underwent OLIF (OLIF group). There were no significant differences found in the fusion rate [OR = 1.58 (0.95, 2.64), P = 0.08], complication rate [OR = 1.25 (0.93, 1.68), P = 0.14], and visual analog scale for back pain (VAS-BP) [WMD = 0.00 (-0.13, 0.14), P = 0.96] between the two groups. Compared with the TLIF group, the OLIF group had a lower Oswestry disability index (ODI) [WMD = -0.62 (-1.03, -0.20), P = 0.003], a higher foramen height (FH) [WMD = 2.03 (1.42, 2.46), P < 0.001], a higher disc height (DH) [WMD = 1.69 (1.17, 2.22), P < 0.001], and a shorter length of stay (LOS) [WMD = -1.80 (-2.55, -1.05), P < 0.001]. Conclusion: In the treatment of lumbar degenerative diseases, compared with TLIF, OLIF has more advantages in terms of improving the lumbar function, restoring the FH and DH, and shortening the LOS. Both methods have comparable fusion rates, complication rates, and lumbar pain improvements. Due to the small amount of research and unclear assessment of the risk of bias, high-quality, large-sample randomized controlled studies are required to prove it.

Orf virus as an adjuvant enhances the immune response to a PCV2 subunit vaccine.

Orf virus (ORFV), a member of the genus Parapoxvirus, possesses an excellent immune activation capability, which makes it a promising immunomodulation agent. In this study, we evaluated ORFV as a novel adjuvant to enhance the immune response of mice to a subunit vaccine using porcine circovirus type 2 (PCV2) capsid (Cap) protein as a model. Our results showed that both inactivated and live attenuated ORFV activated mouse bone marrow-derived dendritic cells and increased expression of immune-related cytokines interleukin (IL)-1ß, IL-6, and TNF-α. Enhanced humoral and cellular immune responses were induced in mice immunized with PCV2 Cap protein combined with inactivated or live attenuated ORFV adjuvant compared with the aluminum adjuvant. Increased secretion of Th1 and Th2 cytokines by splenic lymphocytes in immunized mice further indicated that the ORFV adjuvant promoted a mixed Th1/Th2 immune response. Moreover, addition of the ORFV adjuvant to the PCV2 subunit vaccine significantly reduced the viral load in the spleen and lungs of PCV2-challenged mice and prevented pathological changes in lungs. This study demonstrates that ORFV enhances the immunogenicity of a PCV2 subunit vaccine by improving the adaptive immune response, suggesting the potential application of ORFV as a novel adjuvant.

Emulsion template fabricated heterogeneous bilayer gelatin-based scaffolds with sustained-delivery of lycium barbarum glycopeptide for periodontitis treatment.

Periodontitis is a chronic inflammatory disease raising the risks of tooth-supporting structures destruction and even tooth loss. The way to reconstruct periodontal bone tissues in inflammatory microenvironment has been long in demand for periodontitis treatment. In this study, the lycium barbarum glycopeptide (LbGP) loaded gelatin-based scaffolds were fabricated for periodontitis treatment. Gelatin microspheres with suitable size were prepared by emulsification and gathered by oxidized sodium alginate to prepare heterogeneous bilayer gelatin-based scaffolds, and then they were loaded with LbGP. The prepared scaffolds possessed interconnected porous microstructures, good degradation properties, sufficient mechanical properties, sustained release behavior and well biocompatibility. In vitro experiments suggested that the LbGP loaded gelatin-based scaffolds could inhibit the expression of inflammatory factors (IL-1ß, IL-6, and TNF-α), promote the expression of anti-inflammatory factor (IL-10), and the expression of osteogenic markers (BMP2, Runx2, ALP, and OCN) in PDLSCs under the LPS-stimulated inflammatory microenvironment. Moreover, in rat periodontitis models, the LbGP gelatin-based scaffolds would reduce the alveolar bone resorption of rats, increase the collagen fiber content of periodontal membrane, alleviate local inflammation and improve the expression of osteogenesis-related factors. Therefore, the LbGP loaded gelatin-based scaffolds in this study will provide a potential therapeutic strategy for periodontitis treatment.

DP7-C/mir-26a system promotes bone regeneration by remodeling the osteogenic immune microenvironment.

OBJECTIVE: This study investigates the DP7-C/miR-26a complex as a stable entity resulting from the combination of miR-26a with the immunomodulatory peptide DP7-C. Our focus is on utilizing DP7-C loaded with miR-26a to modulate the immune microenvironment in bone and facilitate osteogenesis. METHODS: The DP7-C/miR-26a complex was characterized through transmission electron microscopy, agarose electrophoresis, and nanoparticle size potentiometer analysis. Transfection efficiency and cytotoxicity of DP7-C were assessed using flow cytometry and the CCK-8 assay. We validated the effects of DP7-C/miR-26a on bone marrow mesenchymal stem cells (BMSCs) and macrophages RAW 264.7 through gene expression and protein synthesis assays. A comprehensive evaluation of appositional bone formation involved micro-CT imaging, histologic analysis, and immunohistochemical staining. RESULTS: DP7-C/miR-26a, a nanoscale, and low-toxic cationic complex, demonstrated the ability to enter BMSCs and RAW 264.7 via distinct pathways. The treatment with DP7-C/miR-26a significantly increased the synthesis of multiple osteogenesis-related factors in BMSCs, facilitating calcium nodule formation in vitro. Furthermore, DP7-C/miR-26a promoted M1 macrophage polarization toward M2 while suppressing the release of inflammatory factors. Coculture studies corroborated these findings, indicating significant repair of rat skull defects following treatment with DP7-C/miR-26a. CONCLUSION: The DP7-C/miR-26a system offers a safer, more efficient, and feasible technical means for treating bone defects.

The absolute number of small and diminutive adenomas with high-grade dysplasia is substantially higher compared with large adenomas: a retrospective pooled study.

Introduction: The risk that a large polyp (≥10 mm) evolves into high-grade dysplasia (HGD) is relatively high compared with that of a small/diminutive polyp (<10 mm). Recently, the detection of small and diminutive polyps has been substantially improved with the advancement of endoscopy. However, further research is needed on the role of the incidence of HGD caused by the co-occurrence of small and diminutive polyps in the progression of HGD. In this study, we aim to investigate whether and how the small and diminutive polyps correlate with the incidence of HGD in the population. Methods: The pooled data were deeply analyzed from four published randomized controlled trials (RCTs) regarding colon polyp detection. All polyps detected were examined and confirmed by pathologists. The primary outcome was the composition ratio of the HGD polyps in each polyp size category. Results: Among a total of 3,179 patients with 2,730 polyps identified, there were 83 HGD polyps confirmed, and 68 patients had at least one polyp with HGD. The risk of development of HGD was lower for a single small and diminutive polyp than for one large polyp (2.18% vs. 22.22%, P < 0.0001). On the contrary, the composition ratio for HGD from small and diminutive polyps was significantly higher than that from the large ones (68.67% vs. 31.33%, P < 0.0001). The combined number of HGD presented a trend negatively correlated to size. Conclusions: Our data demonstrated that the absolute number of HGD significantly derives more from small and diminutive polyps than from the large ones, and the collective number of small and diminutive polyps per patient is indicative of his/her HGD exposure. These findings positively provide novel perspectives on the management of polyps and may further optimize the prevention of colorectal cancer. Systematic Review Registration: http://www.chictr.org.cn, identifier ChiCTR1900025235, ChiCTR1800017675, ChiCTR1800018058, and ChiCTR1900023086.

A Bayesian finite mixture model approach to evaluate dichotomization method for correlated ELISA tests.

In diagnostic accuracy studies, a commonly employed approach involves dichotomizing continuous data and subsequently analyzing them using a Bayesian latent class model (BLCM), often relying on binomial or multinomial distributions, rather than preserving their continuous nature. However, this procedure can inadvertently lead to less reliable outcomes due to the inherent loss of information when converting the original continuous measurements into binary values. Through comprehensive simulations, we demonstrated the limitations and disadvantages of dichotomizing continuous biomarkers from two correlated tests. Our findings highlighted notable disparities between the true values and the model estimates as a result of dichotomization. We discovered the crucial significance of selecting a reference test with high diagnostic accuracy in test evaluation in order to obtain reliable estimates of test accuracy and prevalences. Our study served as a call to action for veterinary researchers to exercise caution when utilizing dichotomization.

Ecological and human health hazards of soil heavy metals after wildfire: A case study of Liangshan Yi autonomous prefecture, China.

Soil samples were collected in at different depths from the conflagration area in Liangshan Yi Autonomous Region, China, to investigate the distribution characteristics and ecological and human health risks of heavy metals after a wildfire. The samples collected comprise wildfire ash (WA) above the soil surface, ash soil (AS) 0-5 cm, and plain soil (PS) 5-15 cm below the soil surface. Additionally, reference soil (RS) was collected from a nearby unburned area at the same latitude as the conflagration area. The results showed that the concentrations of zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd) in the WA and AS were significantly higher than in reference soil (RS) (p < 0.05). Concentrations of Pb in the PS were 2.52 times higher than that in RS (17.9 mg kg-1) (p < 0.05). The AS and WA had the highest Index of potential ecological risks (RI > 600). In addition, The Cd in AS and WA contributed the most to the highest Improved nemerow index (INI) and RI with a contribution of more than 80%. The concentration of heavy metals was used to establish non-carcinogenic effects and cancer risks in humans via three exposure pathways: accident ingestion of soil, dermal contact with soil, and inhalation of soil particles. Hazard index (HI) values of each sample were all less than 1, indicating the non-carcinogenic risk was within the acceptable range and would not adversely affect the local population's health. The Cancer risk (CR) values of Cr, As, Cd, and Ni were all below 1 × 10-6, indicating that heavy metal pollution from this wildfire did not pose a cancer risk to residents.

Novel molecular classification and prognosis of papillary renal cell carcinoma based on a large-scale CRISPR-Cas9 screening and machine learning.

Papillary renal cell carcinoma (PRCC) is a highly heterogeneous cancer, and PRCC patients with advanced/metastatic subgroup showed obviously shorter survival compared to other kinds of renal cell carcinomas. However, the molecular mechanism and prognostic predictors of PRCC remain unclear and are worth deep studying. The aim of this study is to identify novel molecular classification and construct a reliable prognostic model for PRCC. The expression data were retrieved from TCGA, GEO, GTEx and TARGET databases. CRISPR data was obtained from Depmap database. The key genes were selected by the intersection of CRISPR-Cas9 screening genes, differentially expressed genes, and genes with prognostic capacity in PRCC. The molecular classification was identified based on the key genes. Drug sensitivity, tumor microenvironment, somatic mutation, and survival were compared among the novel classification. A prognostic model utilizing multiple machine learning algorithms based on the key genes was developed and tested by independent external validation set. Our study identified three clusters (C1, C2 and C3) in PRCC based on 41 key genes. C2 had obviously higher expression of the key genes and lower survival than C1 and C3. Significant differences in drug sensitivity, tumor microenvironment, and mutation landscape have been observed among the three clusters. By utilizing 21 combinations of 9 machine learning algorithms, 9 out of 41 genes were chosen to construct a robust prognostic signature, which exhibited good prognostic ability. SERPINH1 was identified as a critical gene for its strong prognostic ability in PRCC by univariate and multiple Cox regression analyses. Quantitative real-time PCR and Western blot demonstrated that SERPINH1 mRNA and protein were highly expressed in PRCC cells compared with normal human renal cells. This study exhibited a new molecular classification and prognostic signature for PRCC, which may provide a potential biomarker and therapy target for PRCC patients.

A Selective Review on Information Criteria in Multiple Change Point Detection.

Change points indicate significant shifts in the statistical properties in data streams at some time points. Detecting change points efficiently and effectively are essential for us to understand the underlying data-generating mechanism in modern data streams with versatile parameter-varying patterns. However, it becomes a highly challenging problem to locate multiple change points in the noisy data. Although the Bayesian information criterion has been proven to be an effective way of selecting multiple change points in an asymptotical sense, its finite sample performance could be deficient. In this article, we have reviewed a list of information criterion-based methods for multiple change point detection, including Akaike information criterion, Bayesian information criterion, minimum description length, and their variants, with the emphasis on their practical applications. Simulation studies are conducted to investigate the actual performance of different information criteria in detecting multiple change points with possible model mis-specification for the practitioners. A case study on the SCADA signals of wind turbines is conducted to demonstrate the actual change point detection power of different information criteria. Finally, some key challenges in the development and application of multiple change point detection are presented for future research work.

Htr2b Promotes M1 Microglia Polarization and Neuroinflammation after Spinal Cord Injury via Inhibition of Neuregulin-1/ErbB Signaling.

The secondary injury of spinal cord injury (SCI) is dominated by neuroinflammation, which was caused by microglia M1 polarization. This study aimed to investigate the role and mechanism of Htr2b on neuroinflammation of SCI. The BV2 and HMC3 microglia were treated with lipopolysaccharide (LPS) or interferon (IFN)-γ to simulate in vitro models of SCI. Sprague-Dawley rats were subjected to the T10 laminectomy to induce animal model of SCI. Htr2b mRNA expression was measured by qRT-PCR. The expression of Htr2b and Iba-1 was detected by western blot and immunofluorescence. The expression of inflammatory cytokines in vitro and in vivo was also measured. Kyoto Encyclopedia of Genes and Genomes (KEGG) was employed to analyze Htr2b-regulated signaling pathways. Rat behavior was analyzed by the Basso, Beattie, and Bresnahan (BBB) and inclined plane test. Rat dorsal horn tissues were stained by hematoxylin-eosin (H&E) and Nissl to measure neuron loss. Htr2b was highly expressed in LPS- and IFN-γ-treated microglia and SCI rats. SCI modeling promoted M1 microglia polarization and increased levels of inflammatory cytokines. Inhibition of Htr2b by Htr2b shRNA or RS-127445 reduced the expression of Htr2b, Iba-1, and iNOS and suppressed cytokine levels. KEGG showed that Htr2b inhibited ErbB signaling pathway. Inhibition of Htr2b increased protein expression of neuregulin-1 (Nrg-1) and p-ErbB4. Inhibition of the ErbB signaling pathway markedly reversed the effect of Htr2b shRNA on M1 microglia polarization and inflammatory cytokines. Htr2b promotes M1 microglia polarization and neuroinflammation after SCI by inhibiting Nrg-1/ErbB signaling pathway.

Prediction and identification of HLA-A*0201-restricted epitopes from cancer testis antigen CT23.

Cancer-testis antigen CT23 is a class of tumor-associated antigens (TAA) characterized by restricted expression in male germ cells and a variety of tumor tissues. Numerous studies have shown that CT23 is closely related to tumor cell viability, proliferation, metastasis and invasion. CT23 is immunogenic and can cause specific immune response in tumor patients. Therefore, it is considered to be one of the best target antigens for designing therapeutic tumor vaccines and T-cell-mediated tumor immunotherapy. In this study, we initially obtained seven HLA-A*0201-restricted CT23 epitope candidate peptides through the T cell epitope prediction program. Subsequently, a T2 cell binding assay revealed the potential binding of all candidate peptides with HLA-A2 molecules. Notably, peptide P7 (ALLVLCYSI) exhibited the highest affinity, as evidenced by a fluorescence index (FI) of 2.19. Dendritic cells (DCs) loaded with CT23 candidate peptide can stimulate CD8+T cell activation and proliferation, and compared with other candidate peptides, candidate peptide P7 is superior. The cytotoxic T lymphocytes (CTLs) stimulated by the peptide P7 had killing effect on tumor cells (HLA-A*0201+, CT23+), but no killing effect on tumor cells (HLA-A*0201-, CT23+). The CTLs induced by the peptide P7 also had a specific killing effect on T2 cells bearing the peptide P7. In summary, our findings suggest that the CT23 peptide P7 (ALLVLCYSI) can induce immune responses and holds potential for tumor-specific CTL therapy.

Application of integrated problem-based learning combined with lecture-based classroom teaching in undergraduate medical education: An effective teaching model in a Medical School in China.

The problem-based learning (PBL) is increasingly used in undergraduate education. However, the application of integrated PBL to medical undergraduate education has not been well assessed. An observational study was designed to compare integrated PBL combined with lecture-based classroom (LBC) with traditional LBC teaching in 2 semesters of a Medical School in China. This study was conducted from March 2021 to July 2022. A total of 118 undergraduates majoring in clinical medicine were randomly allocated in 2 groups, 1 group receiving the integrated PBL + LBC teaching (experimental group, n = 60) and another group receiving LBC teaching (control group, n = 58). The experimental group attended the integrated PBL courses for the basic and clinical medicine conducted in the 6th and 8th semesters, respectively, as well as taking the LBC courses. The experimental group was required to preview the course materials before class, make presentations in class and take online feedback questionnaires after class, while the control group was required to preview the textbooks and listen to the traditional LBC courses. The students' scores of these 2 groups were compared, and feedback questionnaires were performed to evaluate the effectiveness of the experimental group over the control group. Results showed that the experimental group scored significantly higher than the control group in Clinical Skills (95% confidence interval [CI] 4.19-5.89), Internal Medicine I (95% CI: 1.85-9.93), Internal Medicine II (95% CI: 8.07-15.90), Introduction to Surgery (95% CI: 5.08-10.25), Surgery (General Surgery) (95% CI: 7.82-12.72), Surgery (Specialty) (95% CI: 6.47-9.97), and Clinical Medical Level Test (95% CI: 1.60-5.15) (all P < .01). In the feedback questionnaires of integrated PBL, up to 80% and 90% of students were satisfied with the teaching methods and lecturers, respectively. More than 80% of students agreed that the integrated PBL improved their abilities to learn independently, understand knowledge, and to raise, analyze and solve problems. In terms of stress in and out of class, a small number of students, <36.7%, felt stressed. The integrated PBL combined with LBC is an effective teaching approach, which may provide new ideas for teaching research and reform on undergraduate medical education in clinical medicine specialty and other medical majors.

Analysis of the incidence of falls and related factors in elderly patients based on comprehensive geriatric assessment.

Objective: To investigate the incidence of falls in elderly aged 65 years and above among outpatients and inpatients, and to analyze its related factors and identify prevention strategies. Methods: A retrospective analysis was conducted on 451 patients aged 65 years and above who received comprehensive geriatric assessment in outpatients and inpatients from the Department of Geriatrics in the Second Xiangya Hospital from March 2021 to March 2022. According to whether there had been at least one fall in the past year, the patients were divided into a fall group and a non-fall group. Data were collected from the We-Chat applet of comprehensive geriatric assessment. A t test and chi-square test were performed to compare the difference between the two groups. Logistic regression analysis was then conducted to identify factors associated with falls. Results: (1) The incidence of falls among the outpatient and inpatient was 28.8%. (2) The rate of light, moderate, and heavy dependence on daily living ability and decreased mobile balance ability were higher in the fall group than those in the non-fall group. The average calf circumference in the fall group was significantly lower than that in the non-fall group. (3) The prevalence of diabetes and eye diseases in the fall group was significantly higher than that in the non-fall group. (4) The percentage of insomnia and suspicious insomnia cases in the fall group was higher than that in the non-fall group. The mean scores for dysphagia, frailty, and incontinence were higher and the mean malnutrition score was lower in the fall group than in the non-fall group. (5) Multiple logistic regression analysis showed that frailty, insomnia, and malnutrition were independent influencing factors of fall (OR = 1.955, 1.652, 10.719, P = 0.044, 0.041, 0.025, respectively). Conclusions: The incidence of falls among outpatients and inpatients aged 65 years and above is high. Frailty, insomnia, and malnutrition are the main factors influencing falls in these patients.

Hepatic interleukin 32 attenuates liver injury through repression of necroptosis in cholestasis.

OBJECTIVE: We aimed to evaluate the association between interleukin (IL)-32 and necroptosis in cholestatic liver injury. METHODS: Levels of necroptosis-related markers in cholestatic and control patients, including the receptor-interacting serine-threonine kinase 3 (RIPK3), receptor-interacting serine-threonine kinase 1 (RIPK1), and mixed lineage kinase domain-like (MLKL) were measured. Animal experiments in C57BL/6J and transgenic mice with IL32ß/γ overexpression were also conducted to confirm the effect of IL-32 on necroptosis in cholestasis, which was induced by α-naphthylisothiocyanate (ANIT) and 1% lithocholic acid (LCA). PLC/PRF/5-ASBT and primary mouse hepatocytes were utilized for the investigation of the regulation and mechanism of IL-32 in cholestasis. RESULTS: In the liver tissues of cholestatic patients, the mRNA and protein expressions of RIPK1, RIPK3, and MLKL were increased and associated with IL-32 expression. In addition, expressions of these indicators in the liver of 1% LCA- and ANIT-induced mouse models were significantly increased, while they were markedly decreased in hIL32ßLTg and hIL32γLTg mice. After bile acid stimulation, IL-32 and phosphorylated Akt (p-Akt) expressions significantly elevated in a dose-dependent manner. After treated with tumor necrosis factor (TNF)-α, IL-32 inhibited MLKL expression in primary mouse hepatocytes. CONCLUSION: IL-32 is negatively associated with necroptosis in cholestatic patients. Moreover, IL-32 is induced by p-Akt and effectively attenuates necroptosis in ANIT- or 1% LCA-induced cholestasis.

Hydration Status in Older Adults: Current Knowledge and Future Challenges.

Adequate hydration is essential for the maintenance of health and physiological functions in humans. However, many older adults do not maintain adequate hydration, which is under-recognized and poorly managed. Older adults are more vulnerable to dehydration, especially those living with multiple chronic diseases. Dehydration is associated with adverse health outcomes in older adults, and acts as an independent factor of the hospital length of stay, readmission, intensive care, in-hospital mortality, and poor prognosis. Dehydration is a prevalent health problem in older adults, accounting for substantial economic and social burden. This review attempts to provide current knowledge of hydration including patterns of body water turnover, the complex mechanisms behind water homeostasis, the effects of dehydration on the health of the body, and practical guidance for low-intake dehydration in older adults.

Predictive Significance of Claudin-3 for Epithelial Barrier Dysfunction in Chronic Rhinosinusitis With Nasal Polyps.

PURPOSE: The abnormal expression of tight junction (TJ) plays a vital role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, there is no appropriate tool to distinguish and diagnose epithelial barrier defects in clinical practice. This study aimed to evaluate the predictive value of claudin-3 for epithelial barrier dysfunction in CRSwNP. METHODS: In this study, TJ protein levels were evaluated by real-time quantitative polymerase chain reaction, immunofluorescent, and immunohistochemistry staining in control subjects and CRSwNP patients. The receiver operating characteristic (ROC) curve was created to assess the predictive value of TJ breakdown in clinical outcomes. In vitro, human nasal epithelial cells were cultured at the air-liquid interface to analyze the transepithelial electrical resistance (TER) level. RESULTS: The expression levels of occludin, tricellulin, claudin-3, and claudin-10 were decreased (all P < 0.05), and those of claudin-1 was increased (P < 0.05) in CRSwNP patients as compared to healthy subjects. Additionally, claudin-3 and occludin levels were negatively correlated with the computed tomography score in CRSwNP (all P < 0.05), and the ROC curve indicated that the claudin-3 level had the most predictive accuracy in evaluating epithelial barrier disruption (area under the curve = 0.791, P < 0.001). Finally, the time-series analysis showed the highest correlation coefficient between TER and claudin-3 (cross-correlation function = 0.75). CONCLUSION: In this study, we suggest that claudin-3 could be a valuable biomarker for predicting nasal epithelial barrier defects and disease severity in CRSwNP.

Involvement of the 4-coumarate:coenzyme A ligase 4CL4 in rice phosphorus acquisition and rhizosphere microbe recruitment via root growth enlargement.

MAIN CONCLUSION: The 4-coumarate:coenzyme A ligase 4CL4 is involved in enhancing rice P acquisition and use in acid soil by enlarging root growth and boosting functional rhizosphere microbe recruitment. Rice (Oryza sativa L.) cannot easily acquire phosphorus (P) from acid soil, where root growth is inhibited and soil P is fixed. The combination of roots and rhizosphere microbiota is critical for plant P acquisition and soil P mobilization, but the associated molecular mechanism in rice is unclear. 4CL4/RAL1 encodes a 4-coumarate:coenzyme A ligase related to lignin biosynthesis in rice, and its dysfunction results in a small rice root system. In this study, soil culture and hydroponic experiments were conducted to examine the role of RAL1 in regulating rice P acquisition, fertilizer P use, and rhizosphere microbes in acid soil. Disruption of RAL1 markedly decreased root growth. Mutant rice plants exhibited decreased shoot growth, shoot P accumulation, and fertilizer P use efficiency when grown in soil-but not under hydroponic conditions, where all P is soluble and available for plants. Mutant ral1 and wild-type rice rhizospheres had distinct bacterial and fungal community structures, and wild-type rice recruited some genotype-specific microbial taxa associated with P solubilization. Our results highlight the function of 4CL4/RAL1 in enhancing rice P acquisition and use in acid soil, namely by enlarging root growth and boosting functional rhizosphere microbe recruitment. These findings can inform breeding strategies to improve P use efficiency through host genetic manipulation of root growth and rhizosphere microbiota.

Characteristics and Application of a Novel Cold-Adapted and Salt-Tolerant Protease EK4-1 Produced by an Arctic Bacterium Mesonia algae K4-1.

Mesonia algae K4-1 from the Arctic secretes a novel cold-adapted and salt-tolerant protease EK4-1. It has the highest sequence similarity with Stearolysin, an M4 family protease from Geobacillus stearothermophilus, with only 45% sequence identity, and is a novel M4 family protease. Ek4-1 has a low optimal catalytic temperature (40 °C) and is stable at low temperatures. Moreover, EK4-1 is still active in 4 mol/L NaCl solution and is tolerant to surfactants, oxidizing agents and organic solvents; furthermore, it prefers the hydrolysis of peptide bonds at the P1' position as the hydrophobic residues, such as Leu, Phe and Val, and amino acids with a long side chain, such as Phe and Tyr. Mn2+and Mg2+ significantly promoted enzyme activity, while Fe3+, Co+, Zn2+ and Cu2+ significantly inhibited enzyme activity. Amino acid composition analysis showed that EK4-1 had more small-side-chain amino acids and fewer large-side-chain amino acids. Compared with a thermophilic protease Stearolysin, the cold-adapted protease EK4-1 contains more random coils (48.07%) and a larger active pocket (727.42 Å3). In addition, the acidic amino acid content of protease EK4-1 was higher than that of the basic amino acid, which might be related to the salt tolerance of protease. Compared with the homologous proteases EB62 and E423, the cold-adapted protease EK4-1 was more efficient in the proteolysis of grass carp skin, salmon skin and casein at a low temperature, and produced a large number of antioxidant peptides, with DPPH, ·OH and ROO· scavenging activities. Therefore, cold-adapted and salt-tolerant protease EK4-1 offers wide application prospects in the cosmetic and detergent industries.

Predicted the structural diversity and electronic properties of Pt-N compounds under high pressure.

The nitrogen-rich transition metal nitrides have attracted considerable attention due to their potential application as high energy density materials. Here, a systematic theoretical study of PtNxcompounds has been performed by combining first-principles calculations and particle swarm-optimized structure search method at high pressure. The results indicate that several unconventional stoichiometries of PtN2, PtN4, PtN5, and Pt3N4compounds are stabilized at moderate pressure of 50 GPa. Moreover, some of these structures are dynamically stable even when the pressure release to ambient pressure. TheP1-phase of PtN4and theP1-phase of PtN5can release about 1.23 kJ g-1and 1.71 kJ g-1, respectively, upon the decomposition into elemental Pt and N2. The electronic structure analysis shows that all crystal structures are indirect band gap semiconductors, except for the metallic Pt3N4withPcphase, and the metallic Pt3N4is a superconductor with estimated critical temperatureTcvalues of 3.6 K at 50 GPa. These findings not only enrich the understanding of transition metal platinum nitrides, but also provide valuable insights for the experimental exploration of multifunctional polynitrogen compounds.