Functionalized selenium nanoparticles ameliorated acetaminophen-induced hepatotoxicity through synergistically triggering PKCδ/Nrf2 signaling pathway and inhibiting CYP 2E1

Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.

In Vivo Studies and Flow Cytometric Investigation on Anticancer Potential of Selenium Nanoparticles Synthesized via Aqueous Extract of Clerodendron phlomidis

Nowadays,doctors and nutritionists recommend individuals incorporate selenium-rich foods such as nuts,cereals,and mushrooms into their regular diet to maintain fitness and overall health.Selenium nanoparticles(SeNPs)exhibit strong chemopreventive capabilities.The anticipations for SeNPs with enhanced and tunable bioactive activities have led to a keen interest in phytofabrication.In this study,the aqueous extract of Clerodendron phlomidis plant leaves was utilized for the synthesis of SeNPs.In traditional Indian medicine,this plant extract is recognized as a significant anti-diabetic agent.The flavonoids tetrahydroxylflavone,7-hydroxyflavanone,and 6,4’-dimethyl-7-acetoxy-scutellarein present in this plant leaf extract demonstrate excellent anticancer activity.These secondary metabolites exhibit the ability to reduce sodium selenite into SeNPs.At a concentration of 13μg/mL,the synthesized SeNPs effectively inhibited the proliferation of the HepG2 cell line.The results suggest that the SeNPs possess promising anti-cancer potential against liver cancer and can be considered as a therapeutic agent for liver cancer treatment.Additionally,the cell cycle arrest induced by SeNPs was further confirmed by the fluorescence-activated cell sorting(FACS)method,indicating that SeNPs could efficiently differentiate cancer cells from normal cells.Notably,it showed a significant improvement in diethylnitrosamine(DEN)-induced Swiss Wistar rat groups.This scientific investigation highlights the high anti-cancer potential of SeNPs,positioning them as a promising therapeutic agent for liver cancer treatment.

Inhibition of H_(2)O_(2)-induced apoptosis of GC2-spg cells by functionalized selenium nanoparticles with lentinan through ROSmediated ERK/p53 signaling pathways

AH_(2)O_(2)-induced oxidative stress injury cell model was established to investigate the antioxidant effect of nanoselenium on mouse spermatocyte lines and the regulation mechanism of the expression level and activity of seleniumcontaining antioxidant enzymes induced by oxidative stress.A safe and effective nano-drug system of functionalized selenium-containing nanoparticles(SeNPs)was developed with lentinan(LNT)(SeNPs@LNT).Mice spermatocyte line GC2-spg cells were treated with SeNPs@LNT(1,2,4,8,16,32μM)for 24-72 h to evaluate the cytotoxicity of selenium.GC2-spg cells were randomly divided into the following groups:control,hydrogen peroxide(H_(2)O_(2)),SeNPs@LNT,and H_(2)O_(2)+SeNPs@LNT groups.H_(2)O_(2)+SeNPs@LNT group was pretreated with SeNPs@LNT 4μM for 12 h,followed by H_(2)O_(2)600μM for 8 h.The cell viability decreased in the H_(2)O_(2) group and increased significantly in the SeNPs@LNT group.Compared with the H_(2)O_(2) group,the SeNPs@LNT+H_(2)O_(2) group exhibited obvious red fluorescence,indicating a higher level of mitochondrial membrane potential.The content of intracellular reactive oxygen species(ROS)in the SeNPs@LNT group reduced significantly,and the intensity of green fluorescence in the SeNPs@LNT+H_(2)O_(2) group decreased significantly compared with the H_(2)O_(2) group,indicating the inhibitory effect of SeNPs@LNT on the generation of ROS-induced oxidative stress.The activity of GPx and SOD increased significantly in the SeNPs@LNT group.The expression of p53 decreased significantly under the intervention of nano-selenium,and GPx1 expression increased.In the oxidative stress group,the expressions of DNA damage-related proteins and apoptosis-related proteins were higher than those in other groups.Thus,SeNPs@LNT can promote GC2-spg cell proliferation,improve GPx and SOD activities,remove intracellular ROS,and reduce mitochondrial damage and functional abnormalities caused by oxidative stress by regulating the ERK and p53 protein levels.SeNPs@LNT has good biological activity and antioxidant effect,which can be used to protect the male reproductive system from oxidative stress.

Inhibition of H_(2)O_(2)-induced TM3 cell apoptosis by oxidative stress by lentinan functionalized selenium nanoparticles through JAK2/STAT-3 and P53 pathways

Background:Nano-selenium has been widely used in antiviral and anticancer therapy,and has the advantages of good targeting and low toxicity.For the first time,we combined male reproduction with nano-selenium to investigate its antioxidant effect.This study investigated the protective effect of lentinan functionalized selenium nanoparticles on oxidative stress injury of the hydrogen peroxide(H_(2)O_(2))-induced Leydig cell line,TM3.Methods:The suitable concentration of nano-selenium treatment to promote cell proliferation was also discussed.The concentration of 4μM could significantly promote the growth of TM3 cells.Oxidative stress damage was caused using an 800μM concentration of hydrogen peroxide.The cells were divided into four groups:normal control group,oxidative stress treatment group,H_(2)O_(2)+SeNPs@LNT group,and SeNPs@LNT group.The H_(2)O_(2)+SeNPs@LNT group was pretreated with 4μM of SeNPs@LNT for 12 h,followed by 800μM of H_(2)O_(2)for 8 h.Results:Nano-selenium could significantly promote the proliferation and viability of TM3 cells.SeNPs@LNT treatment increased the level of mitochondrial membrane potential in normal cells and slowed down the decline in mitochondrial membrane potential level caused by oxidative stress injury.In addition,the increase in reactive oxygen species caused by oxidative stress was inhibited by SeNPs@LNT treatment.The apoptosis of TM3 cells was detected,and SeNPs@LNT alleviated the necrosis and apoptosis of TM3 cells induced by H_(2)O_(2).Nano-selenium plays a protective role against oxidative H_(2)O_(2)-induced stress injury in TM3 cells through the changes in the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway and P53 pathway,and the expression levels of other related proteins,protein kinase B(AKT)and C3.Conclusion:SeNPs@LNT exhibited good biological activity and antioxidant effect and can thus be used to protect the male reproductive system from oxidative stress.

Targeted anti-tumor synergistic effects of Myc decoy oligodeoxynucleotides-loaded selenium nanostructure combined with chemoradiotherapy on LNCaP prostate cancer cells

In the present study,we investigated the synergistic effects of targeted methotrexate-selenium nanostructure containing Myc decoy oligodeoxynucleotides along with X-irradiation exposure as a combination therapy on LNCaP prostate cancer cells.Myc decoy ODNs were designed based on the promoter of Bcl-2 gene and analyzed by molecular docking and molecular dynamics assays.ODNs were loaded on the synthesized Se@BSA@Chi-MTX nanostructure.The physicochemical characteristics of nanostructures were determined by FTIR,DLS,UV-vis,TEM,EDX,in vitro release,and hemolysis tests.Subsequently,the cytotoxicity properties of them with and without X-irradiation were investigated by uptake,MTT,cell cycle,apoptosis,and scratch assays on the LNCaP cell line.The results of DLS and TEM showed negative charge(−9 mV)and nanometer size(40 nm)for Se@BSA@Chi-DEC-MTX NPs,respectively.The results of FTIR,UV-vis,and EDX showed the proper interaction of different parts and the correct synthesis of nanoparticles.The results of hemolysis showed the hemocompatibility of this nanoparticle in concentrations less than 6 mg/mL.The ODNs release from the nanostructures showed a pH-dependent manner,and the release rate was 15%higher in acidic pH.The targeted Se@BSA@Chi-labeled ODN-MTX NPs were efficiently taken up by LNCaP cells by targeting the prostate-specific membrane antigen(PSMA).The significant synergistic effects of nanostructure(containing MTX drug)treatment along with X-irradiation showed cell growth inhibition,apoptosis induction(~57%),cell cycle arrest(G2/M phase),and migration inhibition(up to 90%)compared to the control.The results suggested that the Se@BSA@Chi-DEC-MTX NPs can potentially suppress the cell growth of LNCaP cells.This nanostructure system can be a promising approach for targeted drug delivery and chemoradiotherapy in prostate cancer treatment.

A New Method for the Synthesis of Selenium Nanoparticles and the Application to Construction of H_2O_2 Biosensor

The well-distributed, stable selenium nanoparticles (10 nm) with good adhesive ability and biocompatibility were successfully synthesized by using the template of chitosan cross-linked with glutaradehyde. The resulting selenium nanoparticles were used as a new carrier for horseradish peroxidase to construct H2O2 biosensors with good performances.

Testing Toxicity and Antidote Effect of Selenium Nanoparticles with <i>Paramecium caudatum</i>

A simple method for assessment of the toxicity and antidote effect of selenium nanoparticles with Paramecium caudatum is presented. Light microscopy in combination with computerized video tracking is employed for the determination of the survival time of P. caudatum. Up to 800 mg/L, selenium nanoparticles are not acutely toxic. With respect to a potential antidote effect, the lethality of silver nanoparticles, silver nitrate, sodium hydrogen selenite, and sodium selenite to P. caudatum was decreased and survival time was extended upon pre-treatment with selenium nanoparticles. Taken together, these findings suggest that administration of selenium nanoparticles attenuates exposure to toxicants. Selenium nanoparticles could be a good functional additive for food management in animals.

Gutmicrobiome modulation:Ancillary effects of inorganic nanoparticles on gut microflora

The association of gut microflora and human health is being increasingly recognized,and the impact of gut microflora on the host is well characterized,including the body’s energy metabolism and immune system maintenance.Several human diseases,including metabolic,autoimmune,obesity,hypothyroidism,and intestinal disorders,are closely associated with gut dysbiosis.Inorganic nanoparticles(NPs)are extensively utilized in numerous fields due to their distinctive,attractive physicochemical properties.Estimation of the potential impacts of NPs,with a high number of microorganisms inside the human body(microbiota)and its genomes(microbiome),represents one of the most important aspects of nano-toxicology.This review article aims to provide information on the association of gut microflora alterations to diseases and describe the impacts of various inorganic NPs,including silver,zinc,selenium,titania,silicon,and copper,on gut microflora.Research on the effect of inorganic NPs on gut microflora of animal models and the poultry industry is reviewed.The response of pathogenic Enterobacter species to inorganic NPs has been expounded in detail.This review also highlights the need to focus on the ancillary effects of various inorganic NPs on gut microflora to expedite the suitable advancement of these particles for future use.Finally,the key opportunistic areas for the application of nanotechnology are underlined to manipulate the microbiome of gut dysbiosis,provide an overview,and address potential challenges and our perspective on this evolving field.

纳米硒联合聚维酮碘对手术感染杀菌的效果

【目的】负载多功能纳米硒聚维酮碘(PVP-I@Se)消毒剂对金黄色葡萄球菌(SA)、耐甲氧西林金黄色葡萄球菌(MRSA)的杀菌效果,为皮肤手术部位消毒提供实验依据。【方法】实验分为PVP-I组(对照组)与PVPI@Se组(实验组),两组的碘浓度梯度相同,分别为50、75、100、200和400μg/mL,实验组硒浓度2μg/mL,对照组不添加硒,比较两组不同的消毒液对SA、MRSA的消毒效果,检测指标包括最低抑菌浓度(MIC)和最低杀菌浓度(MBC);碘浓度50μg/mL时的最短杀菌时间;碘浓度200μg/mL、400μg/mL时的抑菌圈大小。【结果】对照组对SA、MRSA的MIC均为79.17μg/mL、实验组分别为54.17和70.83μg/mL。而对照组对SA、MRSA的MBC分别为129.17和150.00μg/mL,实验组分别为70.83和87.50μg/mL。碘浓度50μg/mL时,对照组对SA、MRSA的最短杀菌时间为130 s、140 s,实验组分别为65 s、75 s。碘浓度200μg/mL时,对照组对SA、MRSA的抑菌圈直径分别为7.67 mm、8.33 mm,实验组均为9.50 mm。碘浓度400μg/mL时,对照组对SA、MRSA的抑菌圈直径分别为9.00 mm、9.33 mm,实验组分别为11.67 mm、12.00 mm。【结论】在聚维酮碘浓度为50、75、100、200和400μg/mL时,分别加入浓度为2μg/mL的硒,可增强其对SA、MRSA的杀菌效果、缩短作用时间。硒(SeNPs)加入PVP-I对SA、MRSA的杀菌效果均有增效作用。但增敏效果SA较MRSA显著。MRSA的增效作用对碘浓度(400μg/mL)需求较高。为临床精准选用消毒剂的浓度和作用时间,降低临床皮肤手术部位感染提供理论依据。

猴头菇多糖-纳米硒的制备、结构表征及其生物活性研究

以亚硒酸钠为硒源,利用微生物将无机硒转化为纳米硒(SeNPs),在此基础上,以猴头菇多糖为载体制备得到猴头菇多糖-纳米硒(HEPS-SeNPs).通过傅里叶变换红外光谱仪、X射线衍射仪、扫描电子显微镜、纳米粒度仪、透射电子显微镜等对纳米硒及猴头菇多糖-纳米硒进行结构表征;同时以SeNPs为对照,探究HEPS-SeNPs的抗氧化活性及对HepG_(2)细胞、PC12细胞、RAW264.7细胞细胞存活率的影响.结果表明:所制备的纳米硒及猴头菇多糖-纳米硒均为形貌规则、均一的球体,其元素组成均有Se元素检出;其中Se元素的含量高达671.42μg/g和169.63μg/g.傅里叶变换红外光谱表明HEPS主要通过O-H键等基团与纳米硒结合.与纳米硒相比,HEPS-SeNPs的粒径降低7.33%,电位绝对值提高了17.94%.同时,体外试验结果表明,SeNPs和HEPS-SeNPs对细胞均有一定的生物活性.当物质浓度大于0.4 mg/mL时,HEPS-SeNPs的生物活性高于SeNPs.且HEPS-SeNPs能提高抗氧化活性.研究结果为硒多糖的后续研究提供了理论依据.

硫酸软骨素纳米硒的结构表征及其对Hela细胞迁移和侵袭的影响

对硫酸软骨素纳米硒(selenium-chondroitin sulfate nanoparticles,SeCS)的结构进行鉴定,并考察其对Hela细胞迁移和侵袭的影响。以硫酸软骨素为模板,采用亚硒酸钠-维生素C氧化还原法制备SeCS,并运用透射电镜、扫描电镜、X射线光电子能谱仪和傅立叶红外光谱仪对SeCS进行结构表征;通过划痕实验和细胞迁移侵袭实验(Transwell)检测SeCS对Hela细胞迁移及侵袭的影响;通过Western blot免疫印迹法检测SeCS对细胞内基质金属蛋白酶-2(matrix metalloproteinase 2,MMP-2)和基质金属蛋白酶-9(matrix metalloproteinase 9,MMP-9)表达水平的影响。实验结果表明,制备所得的SeCS是零价态的分散良好的球形纳米粒,表面光滑。Hela细胞经20μg/mL SeCS处理后,细胞的迁移率和侵袭率分别从对照组的100%下降到(59.19±7.74)%和(82.43±4.21)%,表明SeCS能够抑制细胞的迁移和侵袭。进一步的研究发现,SeCS下调了MMP-2和MMP-9蛋白的表达量,表明SeCS通过降低MMP-2和MMP-9的蛋白表达来抑制细胞的迁移和侵袭。

姜黄素纳米硒的制备工艺优化、表征及其对酒精性肝损伤的保护作用

目的:探索姜黄素纳米硒(Selenium-curcumin nanoparticles,SeNPs@Cur)的最佳制备工艺参数,并评价其对酒精性肝损伤的保护作用。方法:在单因素实验基础上,以粒径为指标,选择姜黄素浓度、抗坏血酸与亚硒酸钠摩尔比(V_(C):Na_(2)SeO_(3))、反应时间和反应温度为考察因素,通过响应面优化SeNPs@Cur的工艺参数,并采用扫描电子显微镜(Scanning electron microscope,SEM)、傅里叶变换红外光谱仪(Fourier transform infrared spectrometer,FT-IR)和能谱仪(Energy dispersive spectrometer,EDS)表征其结构。采用MTT法测定其对乙醇诱导LO2细胞损伤的保护作用。结果:SeNPs@Cur的最佳制备工艺参数为:姜黄素浓度5.92 mg/mL、V_(C):Na_(2)SeO_(3)摩尔比10.39:1、反应时间1.98 h和反应温度34.00℃,在此条件下制备得到的SeNPs@Cur粒径为(100.79±3.46)nm,样品中姜黄素的载药率为12.80%±0.80%,硒含量为23.32%±0.07%。进一步的结构鉴定发现,制备所得的SeNPs@Cur为分散的球形纳米粒。而且,与模型组相比,经不同浓度SeNPs@Cur处理后,细胞活力从58.06%±0.43%分别提高至71.43%±1.39%、77.33%±3.54%和85.41%±4.61%,表明SeNPs@Cur对乙醇损伤LO2细胞具有保护作用,且呈浓度依赖性。结论:成功获得了具有抗酒精性肝损伤作用的SeNPs@Cur,为姜黄素的剂型改善及其应用提供了新的技术手段和理论参考数据。

Toxicological effects of nanoselenium in animals

The productivity and sustainability of livestock production systems are heavily influenced by animal nutrition.To maintain homeostatic balance in the body of the animal at different phases of life,the percentage of organically active minerals in livestock feed must be optimized.Selenium(Se)is a crucial trace mineral that is required for the maintenance of many functions of the body.Se nanoparticles(SeNPs)attracted considerable interest from researchers for a variety of applications a decade ago,owing to their extraordinary properties.SeNPs offer significant advantages over larger-sized materials,by having a comparatively wider surface area,increased surface energy,and high volume.Despite its benefits,SeNP also has toxic effects,therefore safety concerns must be taken for a successful application.The toxicological effects of SeNPs in animals are characterized by weight loss,and increased mortality rate.A safe-by-strategy to certify animal,human and environmental safety will contribute to an early diagnosis of all risks associated with SeNPs.This review is aimed at describing the beneficial uses and potential toxicity of SeNPs in various animals.It will also serve as a summary of different levels of SeNPs which should be added in the feed of animals for better performance.

蓝莓果渣多酚-纳米硒的制备、表征及抑菌活性

采用超声辅助双水相法提取蓝莓果渣多酚,经大孔树脂X-5纯化后用于制备蓝莓果渣多酚-纳米硒(total polyphenol-selenium nanoparticles,TP-SeNPs)。通过能量色散X射线光谱、傅里叶变换红外光谱、透射电子显微镜和X射线衍射光谱表征TP-SeNPs结构,并测定其抑菌活性。结果显示:硒盐经还原变为单质形态硒,TP的O—H基团和纳米硒原子之间有着类似氢键的相互作用,TP-SeNPs稳定性良好、呈近似球状分散分布的无定形固体、TP-SeNPs对革兰氏阳性菌的抑制效果优于革兰氏阴性菌,其中对李斯特菌的最低抑菌浓度为0.06 mg/mL。TP-SeNPs可有效抑制李斯特菌生物被膜的形成,破坏李斯特菌细胞壁与细胞膜的通透性与完整性,造成细胞内容物泄漏,导致李斯特菌死亡。本研究可为蓝莓果渣与纳米硒的应用提供新思路,为纳米硒抑菌剂的开发提供理论依据。

海藻多糖-纳米硒的结构及其促进水稻硒累积的机理

【目的】以海藻提取物和亚硒酸钠为原料,采用抗坏血酸还原法制备了海藻多糖–纳米硒(APS-SeNPs),以期为富硒大米生产提供高效的富硒肥料。【方法】采用单因素试验和响应面法优化APS-SeNPs的制备工艺;借助傅里叶红外光谱、透射电镜和表面张力仪对APS-SeNPs进行表征。通过开展大田试验,探究0、5、25 mg/L APS-SeNPs叶面喷施对粳稻‘洛稻998’和籼稻‘川香优2号’硒累积的影响。【结果】1)APS-SeNPs的最佳制备工艺:硒添加量2800 mg/L,亚硒酸钠与抗坏血酸的摩尔比19∶100,反应温度32℃,时间20 min。APSSeNPs粒径为38.94 nm,Zeta电位为–52.17 mV。红外分析结果表明,海藻多糖与纳米硒形成了新的Se—O化学键。APS-SeNPs的表面张力为46.23 mN/m,显著低于Na_(2)SeO_(3)。APS-SeNPs在水稻叶片上的持液量为6.28 mg/cm^(2),而Na_(2)SeO_(3)只有3.94 mg/cm^(2)。2)田间试验结果表明,随着APS-SeNPs喷施浓度增加,水稻叶片、稻壳和糙米的硒含量增加,各部位硒含量顺序为叶片>稻壳>糙米。与Na_(2)SeO_(3)处理相比,APS-SeNPs处理的糙米硒含量提高了2.2%~34.5%;两种硒源处理的糙米有机硒占糙米总硒比例为70.9%~85.3%,糙米有机硒比例均随叶面喷施硒浓度增加而下降,但值得一提的是,APS-SeNPs处理的稻米有机硒比例比Na2 SeO3处理高2.1~7.6个百分点。【结论】海藻糖与纳米硒的结合显著降低了Na_(2)SeO_(3)溶液的表面张力,喷施后在叶片上的持液量更多,因而提高了水稻硒的吸收,相应地提高了硒在籽粒中的累积量以及籽粒中的有机硒比例。在水稻灌浆期喷施浓度5 mg/L APS-SeNPs的效果最好,喷施后的稻米硒含量达到国家富硒标准(0.04~0.3 mg/kg),是富硒水稻生产的可行措施。

Replacing dietary sodium selenite with biogenic selenium nanoparticles improves the growth performance and gut health of early-weaned piglets

Selenium nanoparticles(SeNPs)are proposed as a safer and more effective selenium delivery system than sodium selenite(Na_(2)SeO_(3)).Here,we investigated the effects of replacing dietary Na_(2)SeO_(3)with SeNPs synthesized by Lactobacillus casei ATCC 393 on the growth performance and gut health of earlyweaned piglets.Seventy-two piglets(Duroc×Landrace×Large Yorkshire)weaned at 21 d of age were divided into the control group(basal diet containing 0.3 mg Se/kg from Na_(2)SeO_(3))and SeNPs group(basal diet containing 0.3 mg Se/kg from SeNPs)during a 14-d feeding period.The results revealed that SeNPs supplementation increased the average daily gain(P=0.022)and average daily feed intake(P=0.033),reduced(P=0.056)the diarrhea incidence,and improved(P=0.013)the feed conversion ratio compared with Na_(2)SeO_(3).Additionally,SeNPs increased jejunal microvilli height(P=0.006)and alleviated the intestinal barrier dysfunction by upregulating(P<0.05)the expression levels of mucin 2 and tight junction proteins,increasing(P<0.05)Se availability,and maintaining mitochondrial structure and function,thereby improving antioxidant capacity and immunity.Furthermore,metabolomics showed that SeNPs can regulate lipid metabolism and participate in the synthesis,secretion and action of parathyroid hormone,proximal tubule bicarbonate reclamation and tricarboxylic acid cycle.Moreover,SeNPs increased(P<0.05)the abundance of Holdemanella and the levels of acetate and propionate.Correlation analysis suggested that Holdemanella was closely associated with the regulatory effects of SeNPs on early-weaned piglets through participating in lipid metabolism.Overall,replacing dietary Na_(2)SeO_(3)with biogenic SeNPs could be a potential nutritional intervention strategy to prevent earlyweaning syndrome in piglets.

细菌胞外液生物合成纳米硒的理化性质及抗菌活性研究

本文以一株海洋菌株Bacillussp.Q72的胞外液为还原体系,实现了Se(IV)到纳米硒(SeNPs)的生物转化。利用FTIR、UV-Vis、XRD、SEM、TEM、XPS、拉曼光谱、粒度分析等对生物合成SeNPs的理化性质进行了研究,随后考察了SeNPs的抗菌活性和细胞毒性。结果表明,菌株Bacillus sp.Q72胞外液生物合成的SeNPs为球型,平均粒径为187.6nm,其表面包覆着蛋白质、核酸等生物大分子。SeNPs对金黄色葡萄球菌和铜绿假单胞菌均表现出较好的抑菌活性,同时具有较低的细胞毒性。利用细菌胞外液生物合成纳米硒,避免了利用菌体直接还原在分离过程中的繁琐操作,为SeNPs的生物合成提供了新方法。

硫酸盐对粘红酵母X-20富硒能力的调控研究

为了探究硫酸盐对粘红酵母X-20(Rhodotorula glutinis X-20)富硒的影响,在恒定浓度亚硒酸钠和梯度浓度硫酸钠条件下培养R.glutinis X-20,研究硫酸盐对R.glutinis X-20生物量、总硒及硒纳米颗粒的影响,并使用RT-qPCR初步探索了硫酸盐调节R.glutinis X-20富硒的分子机制。研究发现,硫酸钠的添加使菌株的生物量提高了48.5%,总硒及硒纳米颗粒含量分别降低了36.7%和48.8%。RT-qPCR分析显示硫酸盐会抑制硒代谢关键基因CTH、metE、metB的表达,造成硫酸盐存在条件下总硒及硒纳米颗粒含量下降。硫酸盐的添加提高了R.glutinis X-20在亚硒酸钠环境中的生物量,这对富硒酵母产品的大规模生产具有重要意义。同时,RT-qPCR的结果也为R.glutinis X-20在分子生物学上的优化指明了方向。

耐硒菌株Cytobacillus firmus N4的筛选及其对α-葡萄糖苷酶抑制活性的影响

微生物制备纳米硒具有低毒、温和等优点,具有广阔的应用前景。从武汉施加硒肥的土壤中分离纯化得到一株能将亚硒酸钠还原成纳米硒的菌株,对其进行菌种鉴定,测定其耐硒能力和生长动力学曲线,利用扫描电镜对制备的纳米硒颗粒进行表征,并将转化得到的纳米硒及菌株次生代谢产物对α-葡萄糖苷酶的抑制活性进行初步探究。结果表明,在分离纯化的16株菌株中,坚强芽孢杆菌N4(Cytobacillus firmus N4)对亚硒酸钠的最大耐受性为36 mg/mL,产生的纳米硒粒径为150~220 nm。纳米硒质量浓度为0.625 mg/mL时对α-葡萄糖苷酶的抑制率为(25.42±0.69)%;次生代谢产物质量浓度为2.500 mg/mL时,抑制率达到(73.83±4.63)%。Cytobacillus firmus N4具有高耐硒性质,可为纳米硒的生物转化提供基础,且其次生代谢产物有一定的α-葡萄糖苷酶抑制活性,值得进一步深入研究。