Magnesium-incorporated biocomposite scaffolds:A novel frontier in bone tissue engineering

Nonunion represents a crucial challenge in orthopedic medicine,demanding innovative solutions beyond the scope of traditional bone grafting methods.Among the various strategies available,magnesium(Mg)implants have been recognized for their biocompatibility and biodegradability.However,their susceptibility to rapid corrosion and degradation has garnered notable research interest in bone tissue engineering(BTE),particularly in the development of Mg-incorporated biocomposite scaffolds.These scaffolds gradually release Mg2+,which enhances immunomodulation,osteogenesis,and angiogenesis,thus facilitating effective bone regeneration.This review presents myriad fabrication techniques used to create Mg-incorporated biocomposite scaffolds,including electrospinning,three-dimensional printing,and sol-gel synthesis.Despite these advancements,the application of Mg-incorporated biocomposite scaffolds faces challenges such as controlling the degradation rate of Mg and ensuring mechanical stability.These limitations highlight the necessity for ongoing research aimed at refining fabrication techniques to better regulate the physicochemical and osteogenic properties of scaffolds.This review provides insights into the potential of Mg-incorporated biocomposite scaffolds for BTE and the challenges that need to be addressed for their successful translation into clinical applications.

Rejuvenation of BMSCs senescence by pharmacological enhancement of TFEB-mediated autophagy alleviates aged-related bone loss and extends lifespan in middle aged mice

Bone marrow stromal/stem cells(BMSCs)are generally considered as common progenitors for both osteoblasts and adipocytes in the bone marrow,but show preferential differentiation into adipocytes rather than osteoblasts under aging,thus leading to senile osteoporosis.Accumulated evidences indicate that rejuvenation of BMSCs by autophagic enhancement delays bone aging.

Roles of miR-214 in bone physiology and disease

MicroRNAs(miRNAs)are small non-coding RNAs(ncRNAs)that regulate the expression of their targetmRNAs post-transcriptionally.Since their discovery,thousands of highly conserved miRNAs have been identified and investigated for their role in human health and diseases.MiR-214 has been increasingly reported to have an association with the regulation of bone metabolism.Reports suggested that miR-214 controls the critical aspects of osteoblasts(bone-forming cells),including their differentiation,proliferation,viability,and migration.Studies have also reported the functional significance of miR-214 in bone diseases and suggested its candidature as a diagnostic and therapeutic target.Further,targeting miR-214 by other ncRNAs,such as linear ncRNAs and circular RNAs,has provided novel insights into treating bone diseases.This review briefly discusses the contemporary findings of the physiological and pathological roles of miR-214 in bone turnover.In addition,we highlight the important ncRNA/mRNA/miR-214 axes influencing osteoblast differentiation that are of therapeutic importance for the treatment of bone-related diseases.

A tomato HD-zip I transcription factor, VAHOX1, acts as a negative regulator of fruit ripening

Homeodomain-leucine zipper(HD-Zip)transcription factors are only present in higher plants and are involved in plant development and stress responses.However,our understanding of their participation in the fruit ripening of economical plants,such as tomato(Solanum lycopersicum),remains largely unclear.Here,we report that VAHOX1,a member of the tomato HD-Zip I subfamily,was expressed in all tissues,was highly expressed in breaker+4 fruits,and could be induced by ethylene.RNAi repression of VAHOX1(VAHOX1-RNAi)resulted in accelerated fruit ripening,enhanced sensitivity to ethylene,and increased total carotenoid content and ethylene production.Conversely,VAHOX1 overexpression(VAHOX1-OE)in tomato had the opposite effect.RNA-Seq results showed that altering VAHOX1 expression affected the transcript accumulation of a series of genes involved in ethylene biosynthesis and signal transduction and cell wall modification.Additionally,a dual-luciferase reporter assay,histochemical analysis of GUS activity and a yeast one-hybrid(Y1H)assay revealed that VAHOX1 could activate the expression of AP2a.Our findings may expand our knowledge about the physiological functions of HD-Zip transcription factors in tomato and highlight the diversities of transcriptional regulation during the fruit ripening process.

不同品种鹰嘴豆中α-低聚半乳糖与蔗糖的含量分析

【目的】分析不同品种鹰嘴豆中α-低聚半乳糖(α-GOS)与蔗糖的含量差异,以期获得α-GOS含量较高而蔗糖含量相对低的鹰嘴豆品种,为中国鹰嘴豆资源的有效利用提供理论依据。【方法】采用高效液相色谱法分析比较不同品种鹰嘴豆中的α-GOS与蔗糖的含量,利用层析技术从鹰嘴豆中分离纯化一种含量较高的未知三糖,并采用1H-NMR和ESI-TOF-MS表征了未知三糖的结构(鹰嘴豆糖醇)。【结果】在所研究的19种鹰嘴豆品种中,鹰嘴豆糖醇占总的α-GOS的比例均是最高的,约占50%;其次是水苏糖,约占35%。统计分析表明,不同品种的鹰嘴豆中蔗糖的含量差异显著,含量在1.80%～5.22%。不同品种之间α-GOS的含量也有较大差异,总α-GOS的含量在6.35%～8.68%,其中棉子糖含量0.46%～0.92%,鹰嘴豆糖醇含量3.04%～5.06%,水苏糖含量1.64%～3.09%,毛蕊花糖含量0.27%～0.70%。【结论】在19个品种的鹰嘴豆中,品种‘171’含有最高含量的α-GOS和较低含量的蔗糖,‘171’是生产α-GOS的理想原料。

Studies on the Quantitative Structure-activity Relationship of Toxicity of Chlorophenol Serial Compounds in the ab initio Methods and Substitutive Position of Chlorine Atom (N_(PCS))

20 Quantum chemical parameters of chlorophenol compounds were fully optimized by using B3LYP method on both 6-31G^＊ and 6-311G^＊ basis sets. These structural parameters are taken as theoretical descriptors, and the experimental data of 20 compounds＇ aquatic photogen toxicity（-lgEC50） are used to perform stepwise regression in order to obtain two predicted -lgEC50 correlation models whose correlation coefficients R^2 are respectively 0.9186 and 0.9567. In addition, parameters of chlorine atom＇s substitutive positions and their correlations （NPCs） are taken as descriptors to obtain another predicted -lgEC50 model with the correlation coefficient R2 of 0.9444. Correlation degree of each independent variable in the three models is verified by using variance inflation factors （VIF） and t value. In the cross-validation method, cross-validation coefficients q^2 of 3 models are respectively 0.8748, 0.9119 and 0.8993, which indicates that the relativity and prediction ability of this model are superior to those of the model obtained by topological and BLYP methods.

Synthesis of the Biomimetic Polymer: Aliphatic Diamine and RGDS Modified Poly(d,l-lactic acid)

A novel poly（d, /-lactic acid） （PDLLA） based biomimetic polymer was synthesized by grafting maleic anhydride, butanediamine and arg-gly-asp-ser （RGDS） peptides onto the backbone of PDLLA, aiming to overcome the acidity and auto-accelerating degradation of PDLLA during degradation and to improve its biospecificity and biocompatibility. The synthetic copolymer was characterized by FTIR, ^13C NMR and amino acid analyzer （AAA）.

Evaluation of Catalysts and Optimization of Reaction Conditions for the Dehydration of Methyl Lactate to Acrylates

The production of acrylates from biomass-originated lactic acid is of extraordinary importance, to overcome the increasing worldwide shortage of petroleum. In this study, the catalytic dehydration of methyl lactate over a calcium sulfate catalyst, with various promoters, has been carried out to identify potential catalyst/promoter combinations for acrylate production. The best catalyst for methyl acrylate formation in this study has been calcium sulfate, with cupric sulfate and phosphates as promoters. The optimal mass ratio of m（CaSOa） ： m（CuSOa） ： m（Na2HPO4） ： m（KH2PO4） is 150.0 ： 13.8 ： 2.5 ： 1.2. Effects of carrier gas, reaction temperature, feed concentration as well as contact time on the dehydration of methyl lactate have been investigated. With nitrogen as a carrier gas, a combined yield of acrylic acid and methyl acrylate is 63.9% from 60% （by mass） methyl lactate at 400℃ with 7.7 seconds contact time.

Effects of arbuscular mycorrhizal fungi inoculation on arsenic accumulation by tobacco (Nicotiana tabacum L.)

A pot experiment was conducted to study the effects of arbuscular mycorrhizal （AM） fungi （from contaminated or uncontaminated soils） on arsenic （As） uptake of tobacco （Nicotiana tabacurn L.） in As-contaminated soil. Mycorrhizal colonization rate, dry weight, As and P uptake by plants, concentrations of water-extractable As and As fractions were determined. A low mycorrhizal colonization rate （〈 25%） was detected. Our research indicated that AM fungi isolated from polluted soils were no more effective than those from unpolluted soils when grown in symbiosis with tobacco. No significant differences were observed in roots and stalks dry weights among all treatments. Leaves and total plant dry weights were much higher in Glomus versiforme treatment than that in control treatment. As contents in roots and stalks from mycorrhizal treatments were much lower than that from control treatment. Total plant As content exhibited the same trend. P concentrations in tobacco were not affected by colonization, nor were stalks, leaves and total plant P contents. Roots P contents were remarkably lower in HN treatments than in other treatments. Meanwhile, decreased soil pH and lower water-extractable As concentrations and higher levels of As fraction bound to well-crystallized hydrous oxides of Fe and AI were found in mycorrhizal treatments than in controls. The protective effect of mycorrhiza against plant As uptake may be associated with changes in As solubility mediated by changing soil pH. These results indicated that under As stress, proper mechanisms employed by AM fungi can protect tobacco against As uptake. Results confirmed that AM fungi can play an important role in food quality and safety.

Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent:Pathological characteristics

AIM： To investigate the pathological characteristics of non-thermal damage induced by pulsed high intensity focused ultrasound （PHIFU） combined with ultrasound contrast agent （UCA）, SonoVue （Bracco SpA, Milan, Italy） in rabbit liver VX2 tumor. METHODS： Liver VX2 tumor models were established in 20 rabbits, which were divided randomly into PHIFU combined with ultrasound contrast agent group （PHIFU ＋ UCA group） and sham group. In the PHIFU ＋ UCA group, 0.2 mL of SonoVue was injected intravenously into the tumor, followed by ultrasound exposure of Isp 5900 W/cm^2. The rabbits were sacrificed one day after ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. The remaining tumor tissues were sent for 2,3,5-Triphenyltetrazolium chloride （TTC） staining. RESULTS： Before Trc staining, tumor tissues in both the sham and the PHIFU ＋ UCA groups resembled gray fish meat, After TIC staining, the tumor tissues were uniformly stained red, with a clear boundary between tumor tissue and normal tissue, Histological examination showed signs of tumor cell injury in PHIFU ＋ UCA group, with cytoplasmic vacuoles of various sizes, chromatin margination and karyopyknosis. Electron microscopic examination revealed tumor cell volume reduction, karyopyknosis, chromatin margination, intercellular space widening, the presence of high electro＇n-density apoptotic bodies and vacuoles in cytoplasm. CONCLUSION： The non-thermal effects of PHIFU combined with UCA can be used to ablate rabbit liver VX2 tumors.

Molecular Docking and 3D-QSAR Research of Biphenyl Carboxylic Acid MMP-3 Inhibitors

The molecular docking by LigandFit docking of Discovery Studios 2.5 was employed to the three-dimensional quantitative structure-activity relationship（3D-QSAR） studies of biphenyl carboxylic acid MMP3 inhibitors.A significant correlation coefficient was obtained between dock scores and biological activities.Based on the optimal docking conformations,3D-HoVAIF was employed to the QSAR studies of 51 biphenyl carboxylic acid MMP-3 inhibitors.R2 and Q_CV2（leave-one-out,LOO） of the optimal 3D-HoVAIF-PLS model were 0.873 and 0.841 respectively.The conclusions obtained from the PLS analysis were in agreement with the docking results.

基于改进大津法和模糊聚类的CT图像肺实质分割方法的比较研究(英文)

目的比较改进后的大津阈值法和模糊C均值聚类(FCM)两种分割算法在CT图像肺实质分割中的应用。方法选取40例肺部图像,分别采用改进的大津阈值法和模糊C均值聚类法,分割出肺实质区域,同时剔除肺部纵膈、气管。最后,采用主观评价和客观分析(图象一致性和信息熵指标)评价分割效果。结果主观分析显示,改进的大津法得到的图像中虽仍存在肺实质内部间隙,但图中孤立像素点明显减少,且颗粒的边缘也更加光滑。FCM算法分割出的肺实质空洞较少,获得的图像较完整。但有些许粘连,且提取中主气管容易错误地分割到肺实质区域,造成肺实质分割不彻底。客观分析表明,在一致性准则上,两种方法分割结果相差不大,分割出的区域都具有较高的内部区域一致性;从信息熵的角度,FCM法分割效果较好。结论肺部CT图像肺实质的分割中,对于目标与背景灰度有强对比的图像,Otsu法优于FCM法,但在阈值自适应和运算时间方面需要进一步提升;而对于存在不确定性和模糊性的图像,FCM法优于Otsu法,但在抗噪性和分割精度方面需要进一步改进。

Metabolic and molecular analysis of nonuniform anthocyanin pigmentation in tomato fruit under high light

Pigment intensity and patterns are important factors that determine the nutritional and market values of tomato fruits.The acropetal manner of light-dependent anthocyanin accumulation with the highest levels at the stem end of the fruit makes Pro35S:BrTT8 tomato plants an ideal system for investigating the effects of light intensity on anthocyanin biosynthesis.Extensive transcript analyses indicate that anthocyanin pigmentation in Pro35S:BrTT8 plants under high light might be coordinately regulated by the exogenous protein BrTT8 and endogenous proteins SlAN2 and SlMYBL2.Furthermore,yeast two-hybrid assays showed that BrTT8 could interact efficiently with SlAN2,SlMYBL2,and SlAN11.Moreover,the physical interaction between BrTT8 and SlAN2 was validated by FRET.Simultaneous overexpression of SlAN2 and BrTT8 activated significant anthocyanin biosynthesis in infiltrated tobacco leaves.In addition,the ability of SlMYBL2 to suppress anthocyanin accumulation was also demonstrated in infiltrated tobacco leaves.Altogether,these results prove that tissue-specific assemblage of the heterogeneous MYB-bHLH-WD40 complex consisting of SlAN2,BrTT8 and SlAN11 triggers nonuniform anthocyanin accumulation in tomato fruit under high light.Additionally,it is proposed that a negative-feedback loop fulfilled by SlMYBL2 also participates in the regulation of anthocyanin production.

Space-flight Mutation of Streptomyces gilvosporeus for Enhancing Natamycin Production

Mutants of the strain producing natamycin, Streptomyces gilvosporeus, were obtained after space-flight mutation. With respect to the sand spores and slant spores, the mutation ratios were up to 67.6% and 78.3% and the survival ratio was 43.1% and 3.0%, respectively. An improved mutant producing natamycin, S. gilvosporeus LK-45, was screened, which showed natamycin productivity of 1420mg·L^-1. A mutant resistant to 2-deoxy glucose, S.gilvosporeus LK-119, was further obtained using a＇rational screening procedure. The natamycin productivity of 1940mg·L^-1 was achieved when glucose was used as the carbon source.

Cloning,expression and characterization of serine palmitoyltransferase(SPT)-like gene subunit(LCB2) from marine Emiliania huxleyi virus(Coccolithovirus)

The authors have isolated and characterized a novel serine palmitoyltransferase （SPT）-like gene in marine Emiliania huxleyi virus （EhV-99B1）. The open-reading frame （ORF） of EhV99BI-SPT encoded a protein of 496 amino acids with a calculated molecular mass of 96 kDa and Ip 6.01. The results of sequence analysis showed that there was about 31% 45% identity in amino acid sequence with other organisms. The maximum likelihood phylogenetic tree suggested that the EhV99B1-SPT gene possibly horizontally transferred from the eukaryote. Hydrophobic profiles of deduced amino acid sequences suggested a hydrophobic, globular and membrane-associated protein with five transmembrane domains （TMDs） motifs. Several potential N-linked glycosylation sites were presented in SPT. These results suggested that EhV99BI-SPT was an integral endoplasmic reticulum membrane protein. Despite lower sequence identity, the secondary and three-dimensional structures predicted showed that the “pocket” structure element composed of 2a-helices and 4β- sheets was the catalytic center of this enzyme, with a typical conserved “TFTKSFG” active site in the N-terminal region and was very close to those of prokaryotic organisms. However, the N-terminal domain of EhV99B1-SPT most closely resembled the LCB2 catalysis subunit and the C-terminal domain most closely resembled the LCBI regulatory subunit of other organisms which together formed a spherical molecule. This “chimera” was highly similar to the prokaryotic homologous SPT. For a functional identification, the EhV99B1-LCB2 subunit gene was expressed in Escherichia coli, which resulted in significant accumulation of new sphingolipid in E. coli cells.

Expression of Nitrilases in Brassica juncea var. tumida Tsen in Root Galls Caused by Plasmodiophora brassicae

Five commonly-used reference genes： ACT （actin）, UBE （ubiquitin-conjugating enzyme）, RPL2 （ribosomal protein L2）, BRP II （RNA polymerase II subunit）, and NADH （nicotinamide adenine dinucleotide） were examined using geNorm software as reference genes for RT-qPCR. Among the tested reference genes, ACT and UBE were the most stable in all samples. In parallel, expression analysis of nitrilases in Brassica juncea var. tumida, was performed to preliminarily investigate the molecular interactions between nitrilase and clubroot development at 10, 15, 20, 25, 30, and 40 d postinoculation （dpi） with a suspension of resting spores of Plasmodiophora brassicae. The results showed that different gene expressions of nitrilases were regulated during the initial periods of clubroot development. The expression level of BjNIT1 increased sharply from 20 to 40 dpi in infected roots while there were no remarkable changes in healthy roots. From 15 to 30 dpi, the expression levels of BjNIT2 and BjNIT4 in infected roots were lower than those in non-infected roots. Finally, BjNIT2 in treatment was down approximately to control at 40 dpi. Our results suggest that BjNIT1, which promoted overproductions of auxin, might be involved in P. brassicae infection of B. juncea.

Expression of a New hemA Gene from Agrobacterium radiobacter in Escherichia coli for 5-Aminolevulinate Production

A new hemA gene encoding 5-aminolevulinate (ALA) synthase was cloned from Agrobacterium ra- diobacter zju-0121. The ALA synthase catalyzes the pyridoxal phosphate-dependent condensation of succinyl coen- zyme A (succinyl-CoA) and glycine to produce ALA. Four plasmids carrying the A, radiobacter hemA gene were transformed into different E. coli strains. The effects of both genetic and physiological factors on the expression of ALA synthase and ALA production were studied. The results indicated that the final intracellular activity of ALA synthase and the production of ALA in different expression systems varied largely. Among them, the recombinant E. coli BL21 (DE3) harboring the expression plasmid pET28-A. R-hemA was the most suitable one. The effects of isopropyl-β-D-thiogalactopyranoside (IPTG) addition time, IPTG concentration, culture temperature and the initial concentration of precursors and glucose on the ALA production were also evaluated. The expressed ALA synthase accounted for about 23.7% of the intracellular soluble protein. The highest specific activity of ALA syn- thase was 13.8nmol·min-1·mg-1 of intracellular soluble protein. In the batch culture of the recombinant E. coli, the extracellular ALA concentration reached 0.9 g·L-1.

Overexpression of SlOFP20 affects floral organ and pollen development

The OVATE gene was initially identified in tomato and serves as a key regulator of fruit shape.There are 31 OFP members in the tomato genome.However,their roles in tomato growth and reproductive development are largely unknown.Here,we cloned the OFP transcription factor SlOFP20.Tomato plants overexpressing SlOFP20 displayed several phenotypic defects,including an altered floral architecture and fruit shape and reduced male fertility.SlOFP20 overexpression altered the expression levels of some brassinosteroid(BR)-associated genes,implying that SlOFP20 may play a negative role in the BR response,similar to its ortholog OsOFP19 in rice.Moreover,the transcript accumulation of gibberellin(GA)-related genes was significantly affected in the transgenic lines.SlOFP20 may play an important role in the crosstalk between BR and GA.The pollen germination assay suggested that the pollen germination rate of SlOFP20-OE plants was distinctly lower than that of WT plants.In addition,the tomato pollen-associated genes SlCRK1,SlPMEI,LePRK3,SlPRALF,and LAT52 were all suppressed in the transgenic lines.Our data imply that SlOFP20 may affect floral organ and pollen development by modulating BR and GA signaling in tomato.

Expression and Characterization of a Thermostable Xylanase Gene xynA from a Themophilic Fungus in Pichia pastoris

The gene of xylanase （xynA） was amplified by RT-PCR from the total RNA of a themophilic fungus Thermomyces lanuginosus SY2. The sequence analysis showed that gene coding region of mature peptide contained 0.585 kb, which coded 194 amino acids. The putative amino acid sequence and DNA sequence of xylanase from T. lanuginosus SY2 （GenBank no.： GU166389） were 98.97 and 99.49% identical to the other T. lanuginosus （GenBank no.： U35436）. A recombinant plasmid pPIC9K-xynA was constructed by inserting gene xynA into Pichia pastoris secretory vector pPIC9K. Linearized pPIC9K-xynA was transformed into P. pastoris GS115 with the method of electroporation. The recombinant strain was identified by G418 selection and confirmed by PCR analysis. It was induced by 1.0% methanol at 28°C to express the recombinant xylanase. The results showed that the recombinant xylanase was secreted into extracellular fermentation liquid. The highest enzyme activity of 113.5 IU mL-1 and protein content of 889.7 μg mL-1 were detected for 216 h of induction. The optimal pH value and temperature of the enzyme activity was 5.5 and 65°C, respectively. The xylanase activity retained above 80% from pH value 2.5 to 8.5 for 48 h. The enzyme activity was above 85% at incubation temperature of 55°C.

Effects of different valences of cerium ion on conformation of Horseradish Peroxidase

Our previous studies demonstrated that Ce^4＋could induce reactive oxygen species （ROS） burst as a signal to promote pacilitaxel biosynthesis in suspension cultured Taxus cuspidate cells. To further understand the mechanism of cerium ions inducing ROS burst, circular dichroism （CD）, synchronous fluorescence, and electron paramagnetic resonance （EPR） were used to detect them inducing conformational change of horseradish peroxidase （HRP）. Horseradish peroxidase activity was reduced by 78% by 0.1 mmol/L Ce^4＋, whereas it was only reduced by 28% by 0.1 mmol/L Ce^3＋. Circular dichroism spectra showed that the percentage of transition from helical content and other structure to β strands and flturns was 23.1 when induced by Ce^4＋, whereas it was only 13.2 when induced by Ce^3＋. In synchronous fluorescence spectra, Ce^4＋ led to red shift and intensity-elevation of tryptophan fluorescence emission maximum, whereas in the case of Ce^3＋, the results were a contrast to the above. Furthermore, g factor （gx and gy） in electron paramagnetic resonance （EPR） induced by Ce^4＋ and Ce^3＋ was significantly different. These results indicated that the different valence of cerium ion induced various conformations of HRP, and Ce^4＋ was more effective than Ce^3＋. This suggested that Ce^4＋ affected the burst of ROS through changing the conformation of oxidoreductase.