Calcium-binding motif-mediated binding of redundant calcium offers a chimeolysin enhanced bactericidal activity and extended host range under physiological conditions.

OBJECTIVES: Calcium-binding motifs are shared by multiple bacteriophage lysins; however, the influence of calcium on the enzymatic activity and host range of these enzymes is still not understood. To address this, ClyF, a chimeric lysin with a putative calcium-binding motif, was used as a model for in vitro and in vivo investigations. METHODS: The concentration of calcium bound to ClyF was determined by atomic absorption spectrometry. The influence of calcium on the structure, activity and host range of ClyF was assessed by circular dichroism and time-kill assays. The bactericidal activity of ClyF was evaluated in various sera and a mouse model of Streptococcus agalactiae bacteraemia. RESULTS: ClyF has a highly negatively charged surface around the calcium-binding motif that can bind extra calcium, thereby increasing the avidity of ClyF for the negatively charged bacterial cell wall. In line with this, ClyF exhibited significantly enhanced staphylolytic and streptolytic activity in various sera containing physiological calcium, including human serum, heat-inactivated human serum, mouse serum and rabbit serum. In a mouse model of S. agalactiae bacteraemia, intraperitoneal administration of a single dose of 25 µg/mouse ClyF fully protected the mice from lethal infection. CONCLUSIONS: The present data collectively showed that physiological calcium improves the bactericidal activity and host range of ClyF, making it a promising candidate for the treatment of infections caused by multiple staphylococci and streptococci.

Temperature-driven phase transition of Ti2CN from first-principles calculations.

First-principles evolutionary simulations are used to predict the stable compound of Ti2CN. Body-centered tetragonal I41/amd-Ti2CN is found to be more energetically favorable than the other Ti2CN compounds at 0 K. The phase stability as a function of temperature for all relevant competing Ti2CN phases is investigated by means of first-principles calculations and quasi-harmonic approximation. Our calculations predict that I41/amd-Ti2CN undergoes a phase transition to P42/mmc at 1698 K and then to R3̄m at 1872 K. The different effects from the harmonic, electronic and quasi-harmonic contributions to the Gibbs free energy for I41/amd, P42/mmc and R3̄m phases are compared and analyzed. It is found that both the electronic and quasi-harmonic contributions to the Gibbs free energies significantly affect the phase transition curve of Ti2CN. The calculated temperature-dependent lattice parameter is carefully compared with the previous experimental results. We also provide important thermodynamic quantities as the volumetric expansion coefficient and isothermal bulk modulus and discuss their temperature dependence.

Bacillus velezensis LG37: transcriptome profiling and functional verification of GlnK and MnrA in ammonia assimilation.

BACKGROUND: In recent years, interest in Bacillus velezensis has increased significantly due to its role in many industrial water bioremediation processes. In this study, we isolated and assessed the transcriptome of Bacillus velezensis LG37 (from an aquaculture pond) under different nitrogen sources. Since Bacillus species exhibit heterogeneity, it is worth investigating the molecular mechanism of LG37 through ammonia nitrogen assimilation, where nitrogen in the form of molecular ammonia is considered toxic to aquatic organisms. RESULTS: Here, a total of 812 differentially expressed genes (DEGs) from the transcriptomic sequencing of LG37 grown in minimal medium supplemented with ammonia (treatment) or glutamine (control) were obtained, from which 56 had Fold Change ≥2. BLAST-NCBI and UniProt databases revealed 27 out of the 56 DEGs were potentially involved in NH4+ assimilation. Among them, 8 DEGs together with the two-component regulatory system GlnK/GlnL were randomly selected for validation by quantitative real-time RT-PCR, and the results showed that expression of all the 8 DEGs are consistent with the RNA-seq data. Moreover, the transcriptome and relative expression analysis were consistent with the transporter gene amtB and it is not involved in ammonia transport, even in the highest ammonia concentrations. Besides, CRISPR-Cas9 knockout and overexpression glnK mutants further evidenced the exclusion of amtB regulation, suggesting the involvement of alternative transporter. Additionally, in the transcriptomic data, a novel ammonium transporter mnrA was expressed significantly in increased ammonia concentrations. Subsequently, OEmnrA and ΔmnrA LG37 strains showed unique expression pattern of specific genes compared to that of wild-LG37 strain. CONCLUSION: Based on the transcriptome data, regulation of nitrogen related genes was determined in the newly isolated LG37 strain to analyse the key regulating factors during ammonia assimilation. Using genomics tools, the novel MnrA transporter of LG37 became apparent in ammonia transport instead of AmtB, which transports ammonium nitrogen in other Bacillus strains. Collectively, this study defines heterogeneity of B. velezensis LG37 through comprehensive transcriptome analysis and subsequently, by genome editing techniques, sheds light on the enigmatic mechanisms controlling the functional genes under different nitrogen sources also reveals the need for further research.

2-Methylcitrate cycle: a well-regulated controller of Bacillus sporulation.

Bacillus thuringiensis is the most widely used eco-friendly biopesticide, containing two primary determinants of biocontrol, endospore and insecticidal crystal proteins (ICPs). The 2-methylcitrate cycle is a widespread carbon metabolic pathway playing a crucial role in channelling propionyl-CoA, but with poorly understood metabolic regulatory mechanisms. Here, we dissect the transcriptional regulation of the 2-methylcitrate cycle operon prpCDB and report its unprecedented role in controlling the sporulation process of B. thuringiensis. We found that the transcriptional activity of the prp operon encoding the three critical enzymes PrpC, PrpD, and PrpB in the 2-methylcitrate cycle was negatively regulated by the two global transcription factors CcpA and AbrB, while positively regulated by the LysR family regulator CcpC, which jointly account for the fact that the 2-methylcitrate cycle is specifically and highly active in the stationary phase of growth. We also found that the prpD mutant accumulated 2-methylcitrate, the intermediate metabolite of the 2-methylcitrate cycle, which delayed and inhibited sporulation at the early stage. Thus, our results not only revealed sophisticated transcriptional regulatory mechanisms for the metabolic 2-methylcitrate cycle but also identified 2-methylcitrate as a novel regulator of sporulation in B. thuringiensis.

Adjacent-level biomechanics after single-level anterior cervical interbody fusion with anchored zero-profile spacer versus cage-plate construct: a finite element study.

BACKGROUND: The development of adjacent segment degeneration (ASD) following ACDF is well established. There is no analytical study related to effects of plate profile on the biomechanics of the adjacent-level after ACDF. This study aimed to test the effects of plate profile on the adjacent-level biomechanics after single-level anterior cervical discectomy and fusion (ACDF). METHODS: A three-dimensional finite element model (FEM) of an intact C2-T1 segment was built and validated. From this intact model, two instrumentation models were constructed with the anchored zero-profile spacer or the standard plate-interbody spacer after a C5-C6 corpectomy and fusion. Motion patterns, the stresses in the disc, the endplate, and the facet joint at the levels cephalad and caudal to the fusion were assessed. RESULTS: Compared with the normal condition, the biomechanical responses in the adjacent levels were increased after fusion. Relative to the intact model, the average increase of range of motion (ROM) and stresses in the endplate, the disc, and the facet of the zero-profile spacer fusion model were slightly lower than that of the standard plate-interbody spacer fusion model. The kinematics ROM and stress variations above fusion segment were larger than that below. The biomechanical features of the adjacent segment after fusion were most affected during extension. CONCLUSIONS: The FE analysis indicated that plate profile may have an impact on the biomechanics of the adjacent-level after a single-level ACDF. The impact may be long-term and cumulative. The current findings may help explain the decreasing incidence of ASD complications in the patients using zero-profile spacer compared with the patients using cage and plate construct.

Lysine acetylation regulates the function of the global anaerobic transcription factor FnrL in Rhodobacter sphaeroides.

The metabolism of the purple non-sulfur bacterium Rhodobacter sphaeroides is versatile and it can grow under various conditions. Here, we report evidence that the anaerobic photosynthetic metabolism of R. sphaeroides is regulated by protein lysine acetylation. Using a proteomic approach, 59 acetylated peptides were detected. Among them is the global anaerobic transcription factor FnrL, which regulates the biosynthetic pathway of tetrapyrroles and synthesis of the photosynthetic apparatus. Lysine 223 of FnrL was identified as acetylated. We show that all three lysines in the DNA binding domain (K223, K213 and K175) of FnrL can be acetylated by acetyl-phosphate in vitro. A bacterial deacetylase homolog, RsCobB can deacetylate FnrL in vitro. The transcription of genes downstream of FnrL decreased when the DNA binding domain of FnrL was acetylated, as revealed by chromatin immunoprecipitation and acetylation-mimicking mutagenesis. An increasing number of acetylated lysines resulted in a further decrease in DNA binding ability. These results demonstrate that the lysine acetylation can fine tune the function of the oxygen-sensitive FnrL; thus, it might regulate anaerobic photosynthetic metabolism of R. sphaeroides.

Leptin differentially regulates endochondral ossification in tibial and vertebral epiphyseal plates.

Longitudinal bone growth is governed by a complex network of endocrine signals including leptin. In mouse, leptin deficiency leads to distinct phenotypes in bones of the limb and spine, suggesting the appendicular and axial skeletons are subject to differential regulation by leptin. We established primary cultures for the chondrocytes from tibial and vertebral epiphyseal plates. Cellular proliferation and apoptosis were analyzed for the chondrocytes that had been treated with various concentrations of leptin. Crucial factors for chondrocyte proliferation and differentiation, such as BMP7 and Wnt3, were measured in the cells treated with leptin alone or in combination with pharmacological inhibitors of STAT and ERK signaling pathways. Primary culture of tibial epiphyseal plate chondrocytes has greater proliferating capability compared with that of vertebral epiphyseal plate chondrocytes. Leptin could promote the proliferation of tibial epiphyseal plate chondrocytes, while its effect on vertebral epiphyseal plate chondrocytes was inhibitory. Consistently, apoptosis is inhibited in tibial but promoted in vertebral epiphyseal plate chondrocytes by leptin. Importantly, leptin differentially modulates chondrogenic signaling pathways in tibial and vertebral epiphyseal chondrocytes through STAT and ERK pathways. Leptin differentially regulates chondrogenic proliferation and differentiation in appendicular and axial regions of the skeletons. The signaling pathways in these two regions are also distinct and subject to differential regulation by leptin through the STAT pathway in tibial epiphyseal plate chondrocytes but through the ERK pathway in vertebral epiphyseal plate chondrocytes. Therefore, the regulation of leptin is multi-faceted in the distinct anatomical regions of the skeleton. Knowledge gained from this system will provide insights into the pathophysiological causes for the diseases related to bone development and metabolism.

Leptin differentially regulates chondrogenesis in mouse vertebral and tibial growth plates.

BACKGROUND: Leptin plays an important role in mediating chondrogenesis of limb growth plate. Previous studies suggest that bone structures and development of spine and limb are different. The expression of Ob-Rb, the gene that encodes leptin receptors, is vertebral and appendicular region-specific, suggesting the regulation of leptin on VGP and TGP chondrogenesis may be very different. The aim of the present study was to investigate the differential regulation of leptin on the chondrogenesis of vertebral growth plate (VGP) and tibial growth plate (TGP). METHODS: We compared the VGP and TGP from wild type (C57BL/6) and leptin-deficient (ob/ob) mice. We then generated primary cultures of TGP and VGP chondrocytes. By treating the primary cells with different concentrations of leptin in vitro, we analyzed proliferation and apoptosis of the primary chondrocytes from TGP and VGP. We further measured expression of chondrogenic-related genes in these cells that had been incubated with different doses of leptin. RESULTS: Leptin-deficient mice of 8-week-old had shorter tibial and longer vertebral lengths than the wide type mice. Disturbed columnar structure was observed for TGP but not for VGP. In primary chondrocyte cultures, leptin inhibited VGP chondrocyte proliferation but promoted their apoptosis. Collagen IIA and aggrecan mRNA, and the protein levels of proliferation- and chondrogenesis-related markers, including PCNA, Sox9, and Smad4, were downregulated by leptin in a dose-dependent manner. In contrast, leptin stimulated the proliferation and chondrogenic differentiation of TGP chondrocytes at physiological levels (i.e., 10 and 50 ng/mL) but not at high levels (i.e., 100 and 1000 ng/mL). CONCLUSION: Leptin exerts a stimulatory effect on the proliferation and chondrogenic differentiation of the long bone growth plate but an inhibitory effect on the spine growth plate. The ongoing study will shed light on the regulatory mechanisms of leptin in bone development and metabolism.

The two-component signal transduction system YvcPQ regulates the bacterial resistance to bacitracin in Bacillus thuringiensis.

YvcPQ is one of the two-component signal transduction systems that respond to specific stimuli and enable cells to adjust multiple cellular functions. It consists of a histidine kinase YvcQ and a response regulator YvcP. In this study, through searching the consensus sequence recognized by YvcP, we found four YvcP-binding motifs in the promoter regions of genes yvcR (BMB171_C4100), BMB171_C4385, kapD (BMB171_C4525) and BMB171_C4835 in Bacillus thuringiensis BMB171 which is a representative of Bacillus cereus group, and confirmed that these genes are regulated by YvcP. We compared the sequence of yvcPQ and its downstream genes in genus Bacillus, and found two different kinds of yvc locus, one was the yvcPQ-RS in B. subtilis species and the other was the yvcPQ-R-S1S2 in B. cereus group. Furthermore, we found that YvcP activates the transcription of yvcS1S2 (downstream of yvcR) to promote bacterial resistance to bacitracin and deletion of either yvcPQ operon or yvcS1S2 operon renders the bacterial cells more sensitive to bacitracin. This study enriched our understanding of both the YvcPQ's function and the mechanism of bacterial resistance to bacitracin.

Mycobacterium smegmatis†BioQ defines a new regulatory network for biotin metabolism.

Biotin (vitamin H), the sulfur-containing enzyme cofactor, is an essential micronutrient for three domains of life. Given the fact that biotin is an energetically expensive molecule whose de novo biosynthesis demands 20 ATP equivalents each, it is reasonable that bacteria have evolved diversified mechanisms in various microorganisms to tightly control biotin metabolism. Unlike the Escherichia coli BirA, the prototypical bi-functional version of biotin protein ligase (BPL) in that it acts as a repressor for biotin biosynthesis pathway, the BirA protein of Mycobacterium smegmatis (M. smegmatis), a closely relative of the tuberculosis-causing pathogen, Mycobacterium tuberculosis, lacked the DNA-binding activity. It raised a possibility that an alternative new regulator might be present to compensate the loss of regulatory function. Here we report that this is the case. Genomic context analyses of M. smegmatis detected a newly identified BioQ homolog classified into the TetR family of transcription factor and its recognizable palindromes. The M. smegmatis BioQ protein was overexpressed and purified to homogeneity. Size-exclusion chromatography combined with chemical cross-linking studies demonstrated that the BioQ protein had a propensity to dimerize. The promoters of bioFD and bioQ/B were mapped using 5'-RACE. Electrophoretic mobility shift assays revealed that BioQ binds specifically to the promoter regions of bioFD and bioQ/B. Further DNase I foot-printing elucidated the BioQ-binding palindromes. Site-directed mutagenesis suggested the important residues critical for BioQ/DNA binding. The isogenic mutant of bioQ (ΔbioQ) was generated using the approach of homologous recombination. The in vivo data from the real-time qPCR combined with the lacZ transcriptional fusion experiments proved that removal of bioQ gave significant increment with expression of bio operons. Also, expression of bio operons were repressed by exogenous addition of biotin, and this repression seemed to depend on the presence of BioQ protein. Thereby, we believed that M. smegmatis BioQ is not only a negative auto-regulator but also a repressor for bioFD and bioB operons involved in the biotin biosynthesis pathway. Collectively, this finding defined the two-protein paradigm of BirA and BioQ, representing a new mechanism for bacterial biotin metabolism.

Novel compounds in the Zr-O system, their crystal structures and mechanical properties.

With the motivation of exploring new high-strength ceramics, ab initio evolutionary simulations are performed to search for all the stable compounds in the Zr-O system. We have found that not only the traditional compound ZrO2, but also the ordered suboxides R3̅-Zr6O, R3̅c-Zr3O, P3̅1m-Zr2O and P6̅2m-ZrO are stable at zero pressure. The crystal structure of semimetallic P6̅2m-ZrO consists of Zr-graphene layers and can be described as an intercalated version of the ω-Zr structure. An interesting massive Dirac cone is found in the three-dimensional (3D) band structure of P6̅2m-ZrO at the Γ-point. The elastic properties, the hardness and the correlation between the mechanical properties of Zr-O compounds and the oxygen content have been systematically investigated. Surprisingly, the hardest zirconium oxide is not ZrO2, but ZrO. Both P6̅2m-ZrO and P3̅1m-Zr2O exhibit relatively high hardness values of 14 GPa and 10 GPa, respectively. The anisotropic Young's modulus E, torsion shear modulus Gt and linear compressibility ß have been derived for P6̅2m-ZrO and P3̅1m-Zr2O. Further analyses of the density of states, the band structure and the crystal orbital Hamilton population indicate that the electronic structure of Zr-O compounds is directly related to their mechanical properties. The simultaneous occurrence of the 3D-framework of Zr-O and the strong Zr-Zr bonds in P6̅2m-ZrO explains its high hardness.

Transcriptomic analysis reveals nanoplastics-induced apoptosis, autophagy and immune response in Litopenaeus vannamei.

Increasing attention is being paid to the toxic physiological effects of nanoplastics (NPs) on aquatic organisms. However, few studies have systematically evaluated the regulatory mechanisms of NPs on immune response in crustaceans. In this study, a 28-day chronic exposure experiment was conducted in which shrimps were exposed to various 80-nm polystyrene NPs concentrations (0, 0.1, 1, 5 and 10 mg/L). Transcriptomic analysis was used to investigate the regulatory mechanisms of NPs in immune response of Litopenaeus vannamei. With increasing NPs concentration, the total hemocyte count (THC) content decreased, while phagocytosis rate (PR) and respiratory burst (RB) showed trends of first rising and then falling. High concentration (10 mg/L) of NPs caused the destruction of hepatopancreas tissue structure, the shedding of microvilli, the increase number of hepatocyte apoptosis and autophagy structure. With increasing NPs concentration, the lysozyme (Lys), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities first increased and then decrease, while contents of lipid peroxidation and malondialdehyde increased; the expression levels of Toll, MyD88, GPx, SOD, proPO, Lys, and ALF generally increased at first and then decreased. Transcriptional sequencing analysis showed that the pathway of differentially expressed genes in KEGG enrichment mainly included lysosome (ko04142), apoptosis (ko04210) pathways, indicating that the NPs mainly affected the immune regulatory mechanism. Further analysis by Gene Set Enrichment Analysis (GSEA) showed that the up-regulation pathways of NPs activation mainly included immune response-related pathways such as mitochondrial autophagy, DNA repair, autophagosomes signaling pathway. Our results indicated that NPs exposure induced oxidative stress, apoptosis and autophagy in shrimps. This study provides a basis for further understanding of the mechanisms of antioxidant immune regulation by NPs in shrimp and may serve as a reference for healthy ecological culture of shrimp.

Exploring the hypoglycemic mechanism of chlorogenic acids from Pyrrosia petiolosa (Christ) Ching on type 2 diabetes mellitus based on network pharmacology and transcriptomics strategy.

ETHNOPHARMACOLOGICAL RELEVANCE: Pyrrosia petiolosa (Christ) Ching (YBSW) is a Traditional Chinese medicine rich in chlorogenic acids. It is an important component in many Traditional Chinese medicinal hypoglycemic formulas and is commonly used by the Miao people to treat diabetes with good efficacy. Our previous research has suggested that chlorogenic acids may be the active ingredients in YBSW. AIM OF THE STUDY: To explore the mechanisms underlying the anti-type 2 diabetes mellitus (T2DM) hypoglycemic effects of chlorogenic acids contained in YBSW. MATERIALS AND METHODS: In vivo experiments, hematoxylin-eosin staining (HE) staining, and immunohistochemistry (IHC) were used to determine the effects of chlorogenic acids contained in YBSW in rats. mRNA expression profiling, microarray analysis, and network pharmacology were used to analyze the underlying mechanisms of the effects. Finally, apoptosis and changes in the related pathways were evaluated in vitro using a 3-(4,5-dimethyl-2-thia-zolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, quantitative real-time polymerase chain reaction, immunofluorescence (IF) assessment, and flow cytometry. RESULTS: After the administration of isochlorogenic acid B, the levels of triglycerides, serum total cholesterol, and fasting blood glucose significantly decreased. HE and IHC staining revealed that isochlorogenic acid B significantly increased insulin expression in islet cells. Using network pharmacology and RNA-seq Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, we screened the advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE) signaling pathway. We also verified that YBSW and its chlorogenic acid can inhibit apoptosis and downregulate the expression of related mRNA in the AGE-RAGE pathway in RIN-m5f cells. CONCLUSIONS: YBSW exhibits a significant hypoglycemic effect, with chlorogenic acid being an effective component. The therapeutic effect of chlorogenic acids contained in YBSW is mainly realized by promoting insulin secretion and pancreatic tissue repair. Moreover, YBSW substantially mitigates apoptosis via the AGE-RAGE pathway in T2DM.

Stage specific effect of leptin on the expressions of estrogen receptor and extracellular matrix in a model of chondrocyte differentiation.

Endochondral ossification is a dynamic process. The interaction between leptin and estrogen in this process is complicated. Whether there is a stage specific crosstalk between leptin and estrogen in the differentiation process of the chondrocytes in the growth plate remains unknown. The aim of our study was to investigate the effect of leptin on the expression of estrogen receptors and extracellular matrix in ATDC5 cells, an in vitro model of endochondral ossification. First, we quantified the physiological expressions of estrogen receptors α, ß (ERα, ERß), leptin receptor (Ob-Rb), type II and type X collagens in definite stages of endochondral ossification in ATDC5 cells using real-time PCR. Dynamic and stage specific expression characteristics of these target genes were observed. Simultaneous expressions of Ob-Rb with ERα or ERß in ATDC5 cells were also found with dual-label confocal immunofluorescency. Then using Western blotting analysis and/or real-time PCR, we detected that, leptin treatment up-regulated the expressions of ERα, ERß and type II collagen, but down-regulated type X collagen expression and the ERα/ERß ratio in the chondrogenic differentiation stage. Meanwhile, leptin down-regulated the expressions of ERα, type II and type X collagens, and the ERα/ERß ratio, but up-regulated the expression of ERß in the hypertrophic differentiation stage. Significant positive correlation existed between ERα and type II collagen expression, and between the ratio of ERα/ERß and type X collagen production. In summary, the crosstalk between leptin and estrogen receptor might be differentiation stage specific in ATDC5 cells.

Split spinal cord malformation: report of 5 cases in a single Chinese center and review of the literature.

BACKGROUND: Split spinal cord malformation (SSCM) is rare in scoliosis. This study evaluated the safety and effectiveness of one-stage surgical treatment of congenital scoliosis (CS) in patients with SSCM in a single Chinese center. METHOD: A retrospective study of 5 cases who underwent surgery for CS with SSCM (2 type I and 3 type II) from March 2004 to March 2012. Patients included 4 females and 1 male with a mean age of 13.8 years. All patients underwent one-stage posterior fusion surgery with resection of a bony spur firstly in SSCM type I, but we did nothing to the SSCM in type II. Clinical symptoms and radiological changes were evaluated preoperatively and for at least 2 years postoperatively. RESULTS: Preoperatively, 5 patients had variant neurological and other symptoms. They had a mean preoperative Cobb angle of 63 ± 20° and T5-T12 kyphosis of 30 ± 21°. The mean postoperative Cobb angle was 30.2 ± 19.8° with a correction rate of 57.2 ± 17.0%. At the 3-month follow-up the Cobb angle loss was 3.0 ± 6.8°, and at the 2-year follow-up the Cobb angle loss was 6.5 ± 9.7°. Hyperkyphosis was significantly corrected after surgery but correction loss was indicated at the 2-year follow-up (p < 0.01). There were no neurological deficit complications or deteriorated neurological signs postoperatively or at follow-up. CONCLUSIONS: One-stage surgical treatment of CS with SSCM could be safe and effective, but we need further multicenter studies with larger samples. Intraspinal intervention of bone spur was recommended in SSCM type I before deformity correction, while in SSCM type II it was needless.

Percutaneous Curved Vertebroplasty Versus Unipedicular Approach Vertebroplasty for Acute Osteoporotic Vertebral Compression Fractures : A Randomized Controlled Trial.

STUDY DESIGN: Prospective randomized controlled trial. OBJECTIVE: To clarify whether percutaneous curved vertebroplasty (PCVP) is superior to conventional unipedicular approach vertebroplasty (UVP) in patients with acute osteoporotic vertebral compression fractures (OVCFs). SUMMARY OF BACKGROUND DATA: Unilateral curved vertebroplasty devices were designed and applied to provide better control of cement placement, which may be superior to traditional UVP for the treatment of acute OVCFs. MATERIALS AND METHODS: Patients with single-level OVCFs of <6 weeks duration and visual analog scale (VAS) of back pain 5 or more were randomly allocated to undergo PCVP or UVP and were followed up for 1 year. The primary outcome was overall VAS scores for back pain during 12 months of follow-up. The secondary outcomes were scores on the Oswestry disability index at each postprocedure clinic visit. Radiographic (cement distribution) and surgical data (operation time, fluoroscopy frequency, and cement volume) were assessed. Complications and adverse events were recorded. RESULTS: No statistical difference was found between the PCVP and UVP groups with respect to VAS and Oswestry disability index scores at any follow-up time point. Operative time, fluoroscopy frequency, and cement leakage were similar in both groups, while the PCVP techniques had a larger injection of polymethylmethacrylate (5.5 ± 1.4 vs . 4.2 ± 1.0 mL) and a greater dispersion pattern of cement ( P < 0.001). Post hoc observations found that the analgesic effect was positively correlated with the symmetry of bone cement distribution, but not with the surgical method. Two serious adverse events occurred in the vertebroplasty group: one stress ulcer and one allergic reaction. CONCLUSIONS: Although PCVP achieved more symmetrical cement distribution, which seemed to be associated with a greater analgesic effect, PCVP did not result in significantly greater pain relief than a UVP in the 12 months after treatment.

Study on performance and mechanisms of anaerobic oxidation of methane-microbial fuel cells (AOM-MFCs) with acetate-acclimatizing or formate-acclimatizing electroactive culture.

Anaerobic oxidation of methane-microbial fuel cells with acetate-acclimatizing or formate-acclimatizing electroactive culture (A-AOM-MFC and F-AOM-MFC) were designed and operated at room temperature in this study to evaluate and explore the electrochemical performance and mechanisms of methane conversion and electricity generation. The results indicated that A-AOM-MFC output a higher voltage (0.526 ± 0.001 V) and F-AOM-MFC started up in a shorter time (51 d), resulting from different mechanisms of methane-electrogen caused by discrepant microbial alliances. Specifically, in A-AOM-MFC, acetoclastic methanogens (e.g., Methanosaeta) converted methane into intermediates (e.g., acetate) through reversing methanogenesis and carried out the direct interspecific electron transfer (DIET) with Geobacter-predominated electricigens which can oxidize the intermediates to carbon dioxide and transfer electrons to the electrodes. Differently, the intermediate-dependent extracellular electron transfer (EET) existed in F-AOM-MFC between hydro-methanogens (e.g., Methanobacterium) and electricigens (e.g., Geothrix), which was more difficult than DIET. Additionally, hydro-methanogens metabolized methane to produce formate-dominant intermediates more quickly.

Changes of adjacent segment biomechanics after anterior cervical interbody fusion with different profile design plate: single- versus double-level.

Low-profile angle-stable spacer Zero-P is claimed to reduce the morbidity associated with traditional plate and cage construct (PCC). Both Zero-P and PCC could achieve comparable mid- and long-term clinical and radiological outcomes in anterior cervical discectomy and fusion (ACDF). It is not clear whether Zero-P can reduce the incidence of adjacent segment degeneration (ASD), especially in multi-segmental fusion. This study aimed to test the effect of fusion level with Zero-P versus with PCC on adjacent-segment biomechanics in ACDF. A three-dimensional finite element (FE) model of an intact C2-T1 segment was built and validated. Six single- or double-level instrumented conditions were modeled from this intact FE model using Zero-P or the standard PCC. The biomechanical responses of adjacent segments at the cephalad and caudal levels of the operation level were assessed in terms of range of motion (ROM), stresses in the endplate and disc, loads in the facets. When comparing the increase of adjacent-segment motion in single-level PCC fusion versus Zero-P fusion, a significantly larger increase was found in double-level fusion condition. The fold changes of PCC versus Zero-P of intradiscal and endplate stress, and facet load at adjacent levels in the double-level fusion spine were significantly larger than that in the single-level fusion spine during the sagittal, the transverse, and the frontal plane motion. The increased value of biomechanical features was greater at above segment than that at below. The fold changes of PCC versus Zero-P at adjacent segment were most notable in flexion and extension movement. Low-profile device could decrease adjacent segment biomechanical burden compared to traditional PCC in ACDF, especially in double-level surgery. Zero-P could be a good alternative for traditional PCC in ACDF. Further clinical/in vivo studies will be necessary to explore the approaches selected for this study is warranted.

Characteristics of Aflatoxin B1 Degradation by Stenotrophomonas acidaminiphila and It's Combination with Black Soldier Fly Larvae.

Aflatoxin B1 (AFB1) is a common mycotoxin contaminant in cereals that causes severe economic losses and serious risks to the health of humans and animals. In this paper, we investigated the characteristics of AFB1 degradation by black soldier fly larvae (BSFL) combined with commensal intestinal microorganisms. Germ-free BSFL and non-sterile BSFL were reared on peanut meal spiked with AFB1 for 10 days. The result showed that germ-free BSFL and non-sterile BSFL could achieve 31.71% and 88.72% AFB1 degradation, respectively, which indicated the important role of larvae gut microbiota in AFB1 degradation. Furthermore, twenty-five AFB1-degrading bacteria were isolated from BSFL gut, and S. acidaminiphila A2 achieved the highest AFB1 degradation, by 94%. When S. acidaminiphila A2 was re-inoculated to BSFL, the detrimental effect of AFB1 on the growth performance of BSFL was alleviated, and complete AFB1 degradation in peanut meal was obtained. In conclusion, the present study may provide a strategy to degrade AFB1 in feedstuff through bioconversion with BSFL in combination with gut-originated AFB1-degrading bacteria, while providing a sustainable insect protein and fat source to animals.