Global hypomethylation in hepatocellular carcinoma and its relationship to aflatoxin B_1 exposure

AIM:To determine global DNA methylation in paired hepatocellular carcinoma(HCC) samples using several different assays and explore the correlations between hypomethylation and clinical parameters and biomarkers,including that of aflatoxin B 1 exposure.METHODS:Using the radio labeled methyl acceptance assay as a measure of global hypomethylation,as well as two repetitive elements,including satellite 2(Sat2) by MethyLight and long interspersed nucleotide elements(LINE1),by pyrosequencing.RESULTS:By all three assays,mean methylation levels in tumor tissues were significantly lower than that in adjacent tissues.Methyl acceptance assay log(mean ± SD) disintegrations/min/ng DNA are 70.0 ± 54.8 and 32.4 ± 15.6,respectively,P = 0.040;percent methylation of Sat2 42.2 ± 55.1 and 117.9 ± 88.8,respectively,P < 0.0001 and percent methylation LINE1 48.6 ± 14.8 and 71.7 ± 1.4,respectively,P < 0.0001.Aflatoxin B 1 albumin(AFB 1-Alb) adducts,a measure of exposure to this dietary carcinogen,were inversely correlated with LINE1 methylation(r =-0.36,P = 0.034).CONCLUSION:Consistent hypomethylation in tumor compared to adjacent tissue was found by the three different methods.AFB 1 exposure is associated with DNA global hypomethylation,suggesting that chemical carcinogens may influence epigenetic changes in humans.

Isolation and Characterization of Recombinant Variable Domain of Heavy Chain Anti-idiotypic Antibodies Specific to Aflatoxin B_1

Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain （VHH）. The recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. In particular, they might be very useful for molecular mimicry. The present study demonstrated an alpaca immunized with the F（ab＇）z fragment of anti-aflatoxin B1 mAb and developed an important anti-idiotypic （anti-ld） responses. Antigen-specific elution method was used for panning private anti-ld VHHs from the constructed alpaca VHH library. The selected VHHs were expressed, renatured, purified, and then identified by a competitive enzyme-linked immunosorbent assay （ELISA）. Our findings indicated that the VHH would be an alternative tool for haptens mimicry studies.

Effects of Ginkgo biloba extract on expression of biomarkers during aflatoxin B_1-induced hepatocarcinogenesis in Wistar rats

Objective： The aim of this study was to study the effect of Ginkgo biloba extract （EGb761） on metabolism of afiatoxin B1 （AFB1） in Wistar rats. Methods： Seventy one Wistar rats were assigned at random to groups A, B and C. Rats in groups A, B were injected with AFB1 （intraperitoneal, 100-200 ug/kg body weight, 1-3 times/week）. Group C was normal control. Rats in group B were fed in food with EGb761, while rats in groups A, C were given normal food. Blood samples were collected and liver biopsies were performed on the 14th, 28th and 42nd week. All the rats were sacrificed on the 64th week. The incidence of hepatocarcinoma was investigated. The hepatic phase I drug-metabolizing enzyme Cytochrome-P450 （CYP450） and phase II metabolizing enzyme glutathione S-transferase （GST） were analyzed with spectrometry. Serum AFB1- lysine adduct levels were assessed with high performance liquid chromatography （HPLC）. The expression of 8-hydroxydeoxy- guanosine （8-OHdG） was measured with immunohistochemistry. Results： The incidence of hepatocellular carcinoma （HCC） in group B was significantly lower than that in group A （26.92% vs 76.00%, P 〈 0.001）. No HCC developed in group C. EGb761 showed no effects on the activities of CYP450 and GST in rat liver tissues. The level of AFB1-lysine adduct reached the peak （4356.01 pg/mg albumin） at the 14th week in group A. EGb761 significantly inhibited the formation of AFB1-lysine adduct in serum by 13.07% at the 14th week （P = 0.033）, and 73.63% at the 42nd week （P = 0.002）. The expression of 8-OHdG protein in rat liver tissues in group B was significantly lower than that in group A at the 28th, 42nd, and 64th week （P 〈 0.05）. Conclusion： The main mechanism underlying the effect of EGb761 in blocking hepatocarcinogenesis induced by AFB1 may not be fully attributable to its influence on the activity of liver phase I and phase II metabolizing enzymes. EGb761 inhibits the production of AFB1-lysine adducts, decreases the expression of 8-OHdG protein, and finally alleviates the DNA oxidative injury, which may be one of the mechanisms for the effects of EGb761 in inhibiting or delaying AFB1-induced hepatocarcinogenesis.

Optimization of Extraction Process of Aflatoxin B_1 from Tartary Buckwheat Bran

In this study, the extraction process of aflatoxin B~ from tartary buckwheat bran was optimized with ELISA detection method to determine the optimal conditions for extracting aflatoxin B1 from tartary buckwheat bran. The results of standard recovery test of blank solvent and sample confirmed the feasibility of ELISA detection method. Orthogonal experiment was performed to optimize the solid-liquid ratio, ultrasonic extraction time and ultrasonic amplitude. The results show that it is feasible to detect aflatoxin B1 content with ELISA method. The optimal ultrasonic extraction conditions were ： methanol-water ratio 6： 4, solld-liquid ratio 1 g： 5 ml, ultrasonic extraction time 15 min, ultrasonic amplitude 15 ~. Under the optimized conditions, 1 065.1 ng/L aflatoxin B1 was extracted from tartary buckwheat bran.

The Effects of Dietary Restriction and Aging on in Vivo and in Vitro Binding of Aflatoxin B_1 to Cellular DNA

Laboratory animals maintained on a reduced calorie but nutritionally adequate diet have extended life spans and lowered incidences of spontaneous and chemically induced cancers compared to ad libitum- fed counterparts. Many of the effects of dietary restriction on laboratory animals have been suggested to be related to a deceleration of the aging process. The inhibition of age-related changes in xenobiotic metabolizing enzyme activities by dietary restriction has previously been reported. Alterations of these enzyme activities may cause changes in metabolic activation of carcinogens and, therefore, carcinogen-DNA binding. DNA-repair capability has also been reported to be enhanced in diet-restricted rats. Using AFB1 as a model carcinogen, we have studied in vivo and in vitro hepatic AFB1 -DNA binding, demonstrating that dietary restriction (60% of ad libitum consumption) may decrease the metabolic activation of AFB1, and subsequently reduce AFB 1-DNA binding. Our preliminary results obtained from the AFB 1-DNA binding experiments in isolated hepatocytes suggest that the observed age-dependent reduction in AFB 1-DNA binding which may be attributed to a loss of metabolic activating capability was delayed in the diet-restricted rats.

基于核酸杂交反应的荧光生物传感器的制备及在黄曲霉毒素B_1检测中的应用

采用核酸适配体作为特异性识别元件,SYBR Green I(SGI)荧光染料为信号输出单元,构建了黄曲霉毒素B_1(AFB_1)生物传感器,并对试验条件进行了优化。优化的试验条件如下:适配体互补链与适配体的物质的量比为1.5,SGI加入量为10μL,适配体双链与SGI的作用时间为2 min,适配体与AFB_1作用时间为14 min。结果表明,在AFB_1质量浓度为0.1~1 000μg·L^(-1)时,荧光强度变化量与其质量浓度对数呈线性关系,检出限(3S/N)为0.081μg·L^(-1)。对实际玉米样品进行加标回收试验,回收率为95.2%~105%,测定值的相对标准偏差(n=7)均小于6.0%。与其他适配体传感器进行比较,该方法所构建的荧光适配体传感器对AFB_1的检测具有操作简便、检测范围宽、灵敏度高、特异性强、成本低廉等优点,适合现场快速测定。

2022—2023年合肥市市售花生黄曲霉毒素B_1污染状况及膳食暴露风险评估

目的了解合肥市市售花生中黄曲霉毒素B_1(aflatoxins B_1,AFT B_1)污染情况,进行相应的膳食暴露和健康风险评估,为相关防控措施的制定提供参考。方法2022—2023年通过随机抽样的方式采集合肥市9个县(市、区)中的花生样品,使用同位素稀释液相色谱-串联质谱法对样品中AFT B_1的含量进行测定;通过问卷调查的方式了解合肥市人群的坚果消费情况,以坚果消费量代替花生消费量。分析不同特征人群经花生AFT B_1暴露的情况,估算暴露限值(margin of exposure,MOE)和肝癌发病风险。结果2022—2023年共对合肥市79份花生样品开展AFT B_1检测,检出率为45.57%(36/79),超标率为13.92%(11/79)。男性、女性坚果消费量分别为(4.61±6.12)g/d和(5.21±6.44)g/d,差异无统计学意义(t=1.279,P>0.05);6~17岁、18~59岁以及≥60岁人群的坚果消费量分别为(4.90±6.28)g/d、(3.53±5.66)g/d和(3.90±6.14)g/d,差异有统计学意义(F=7.134,P<0.01)。6~17岁、18~59岁和≥60岁人群经花生的AFT B_1每日膳食暴露量分别为1.70、0.99和1.04 ng/(kg·d),MOE分别为236、403和385,引发的肝癌发病风险分别为每年0.04例/10万人、0.03例/10万人和0.03例/10万人;当严格执行AFT B_1限量标准后,MOE分别为7003、11961和11438,发病风险可分别降至每年0.0015例/10万人、0.0008例/10万人和0.0009例/10万人。结论合肥市售花生样品中AFT B_1检出率较高,建议对合肥市花生中AFT B_1污染水平开展更加全面和持续性的监测工作,并积极采取有效的控制措施,以保障居民的食品安全。

水稻维生素B_1合成相关基因OsTHIC的功能研究

【目的】维生素B_(1)(vitamin B_(1), VB_(1))是生物所必需的微量元素,其作为多个酶的辅因子,参与重要的细胞代谢途径,而水稻中维生素B_(1)合成途径还有待深入研究。本研究旨在解析水稻维生素B_(1)合成相关基因OsTHIC的生物学功能。【方法】综合运用诱变技术、色素测定、Mutmap+、基因编辑及非靶向代谢组分析等手段克隆目的基因并解析其功能。【结果】从EMS诱变的水稻突变体库中发现一个心叶白化致死突变体wll1(white leaf and lethal 1)。wll1从四叶期开始出现心叶白化表型,白化表型逐渐扩展到其他叶片并导致幼苗死亡。与野生型相比,wll1的叶绿素含量与类胡萝卜素含量显著降低。利用Mutmap+及基因编辑技术,确定目的基因为维生素B_(1)合成相关基因OsTHIC。OsTHIC在叶片具有较高表达量,OsTHIC蛋白定位于叶绿体。wll1及OsTHIC的敲除突变体中维生素B_(1)含量均显著低于野生型,外施维生素B_(1)可以恢复wll1的突变表型。外施维生素B_(1)及OsTHIC突变均会影响维生素B_(1)合成相关基因的表达。非靶向代谢组测序分析表明,野生型与wll1差异代谢物在氨基酸的生物合成、辅因子的生物合成、ABC转运器及氨酰基-tRNA的生物合成等方面显著富集。【结论】OsTHIC通过调控维生素B_(1)含量,参与氨基酸合成等代谢过程,在水稻生长发育过程中发挥重要作用。

Foodborne toxin Aflatoxin B_(1)induced glomerular podocyte inflammation through proteolysis of RelA,downregulation of miR-9 and CXCR4/TXNIP/NLRP3 pathway

Aflatoxin B_(1)(AFB_(1))is a naturally-occurring mycotoxin and recognized as the most toxic foodborne toxin,particularly causing damages to kidney.Glomerular podocytes are terminally differentiated epithelial cells.AFB_(1)induces podocyte inflammation,proteinuria and renal dysfunction.Studying the mechanism of AFB_(1)-induced podocyte inflammation and murine kidney dysfunction,we detected that AFB_(1)increased ubiquitindependent degradation of the transcription factor RelA through enhanced interaction of RelA with E3 ubiquitin ligase tripartite motif containing 7(TRIM7)in mouse podocyte clone-5(MPC-5)and mouse glomeruli.Reduction of RelA resulted in decreasing microRNA-9(miR-9)and activating the chemokine receptor 4(CXCR4),thioredoxin interacting protein(TXNIP),and NOD-like receptor pyrin domain-containing 3(NLRP3)signaling axis(CXCR4/TXNIP/NLRP3 pathway),leading to podocyte inflammation.We also determined that downregulation of miR-9 led to CXCR4 expression and the downstream TXNIP/NLRP3 pathway activation.Overexpression of miR-9 or deletion of CXCR4 suppressed AFB_(1)-induced CXCR4/TXNIP/NLRP3 pathway,resulting in alleviating podocyte inflammation and kidney dysfunction.Our findings indicated that ubiquitin-dependent proteolysis of RelA,downregulation of miR-9,and activation of CXCR4/TXNIP/NLRP3 pathway played an essential role in AFB_(1)-induced glomerular podocyte inflammation.Our study revealed a novel mechanism,via RelA,for the control of AFB_(1)’s nephrotoxicity,leading to an effective protection of food safety and public health.

Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1

Terahertz metamaterial biosensors have attracted significant attention in the biological field due to their advantages of label-free,real-time and in situ detection.In this paper,a highly sensitive metamaterial sensor with semi-ring mirror symmetry based on toroidal dipole resonance is designed for a new metamaterial biosensor.It is shown that a refractive index sensitivity of 337.5 GHz per refractive index unit can be achieved under an analyte of saturated thickness near a 1.33 THz transmission dip.For biosensor samples where aflatoxin B1 is dropped on the metamaterial surface in our experiment,dip amplitudes of transmission varying from 0.1904 to 0.203 and 0.2093 are observed as aflatoxin B1 concentrations are altered from 0 to 0.001μg·ml-1 and to 0.01μg·ml-1,respectively.Furthermore,when aflatoxin B1 concentrations are 0.1μg·ml-1,1μg·ml-1,10μg·ml-1 and 100μg·ml-1,dip amplitudes of 0.2179,0.226,0.2384 and 0.2527 and dip redshifts of 10.1 GHz,20.1 GHz,27.7 GHz and 37.6 GHz are respectively observed.These results illustrate high-sensitivity,label-free detection of aflatoxin B1,enriching the applications of sensors in the terahertz domain.

Molecular mechanisms of aflatoxin neurotoxicity and potential neuroprotective agents

Aflatoxins(AFTs)represent one of the most notorious classes of deadly mycotoxins produced by certain fungi that are found on agricultural crops.Aflatoxins are highly toxic to mammals and are known to cause a series of detrimental effects,including neuro-,hepato-,nephron-,and immuno-toxicity.In this original review we summarize the mechanisms of aflatoxin-induced neurotoxicity and the clinical potential of novel neuroprotective agents.Aflatoxin B1(AFB1)is the most toxic congener among the 21 identified AFTs.Recent studies have shown that food borne exposure to AFB1 and/or its metabolites often leads to fatal neurotoxicity in animals and humans.Animal studies indicated that AFB1 exposure could induce abnormal behavioral changes,including anxiety,lethargy disorders,depression-like behavior,cognitive,learning and memory defects,and decreased feeding behavior.Mechanistically,AFB1 exposure has been associated with lipid peroxidation,ablation of non-enzymatic and enzymatic antioxidant defense systems and decreased neurotransmitter levels.AFB1 exposure has also been shown to induce DNA damage,apoptosis,pyroptosis,and mitochondrial dysfunction in the brain tissue.Several signaling pathways,including gasdermin D,toll like receptor 2(TLR2),TLR4,Akt,NF-κB,ERK/MAPK,protein kinase C(PKC),and mitochondrial apoptotic pathways have been shown to participate in AFB1-induced neuronal or astrocyte cell death.Targeting these pathways by small molecules(e.g.,quercetin,curcumin,and gallic acid,and dimethyl fumarate),Chinese herbal extracts(e.g.,Artichoke leaf extract,Chelidonium majus ethanolic extract,pumpkin extract,and Crocus sativus L.tea),and probiotic supplements could effectively improve AFB1-induced neurobehavioral abnormalities and neurotoxicity.To date,the precise molecular mechanisms of AFB1-induced neurotoxicity and potential neuroprotective agents remain unclear.In the present review,the clinical manifestations,molecular mechanisms,and potential neuroprotective agents of AFB1-induced neurotoxicity are summarized in the broadest overview.It is most hopeful that this broad reaching review provides valuable insights and stimulates broader discussion to develop the effective neuroprotective agents against aflatoxins.

Tissue inhibitor of metalloproteinase-3 expression affects clinicopathological features and prognosis of aflatoxin B1-related hepatocellular carcinoma

BACKGROUND The dysregulation of tissue inhibitor of metalloproteinase-3(TIMP3)was positively correlated with the progression of hepatocellular carcinoma(HCC).However,it is not clear whether TIMP3 expression is associated with the clinico-pathological features and prognosis of aflatoxin B1(AFB1)-related HCC(AHCC).A retrospective study,including 182 patients with AHCC,was conducted to explore the link between TIMP3 expression in cancerous tissues and the clinico-pathological characteristics and prognosis of AHCC.TIMP3 expression was detected by immunohistochemistry and its effects on the clinicopathological features and prognosis of AHCC were evaluated by Kaplan-Meier survival analysis and Cox regression survival analysis.Odds ratio,hazard ratio(HR),median overall survival time(MST),median tumor recurrence-free survival time(MRT),and corresponding 95%confidential interval(CI)was calculated to RESULTS Kaplan-Meier survival analysis showed that compared with high TIMP3 expression,low TIMP3 expression in tumor tissues significantly decreased the MST(36.00 mo vs 18.00 mo)and MRT(32.00 mo vs 16 mo)of patients with AHCC.Multivariate Cox regression survival analysis further proved that decreased expression of TIMP3 increased the risk of death(HR=2.85,95%CI:2.04-4.00)and tumor recurrence(HR=2.26,95%CI:1.57-3.26).Furthermore,decreased expression of TIMP3 protein in tissues with AHCC was significantly correlated with tumor clinicopatho-logical features,such as tumor size,tumor grade and stage,tumor microvessel density,and tumor blood invasion.Additionally,TIMP3 protein expression was also negatively associated with amount of AFB1-DNA adducts in tumor tissues.CONCLUSION These findings indicate that the dysregulation of TIMP3 expression is related to AHCC biological behaviors and affects tumor outcome,suggesting that TIMP3 may act as a prognostic biomarker for AHCC.

基于适配体亲和磁珠的黄曲霉毒素B_1单样本前处理试剂盒的制备及应用

黄曲霉毒素B_1(aflatoxin B_1,AFB_1)适配体共价偶联于磁珠表面制备适配体亲和磁珠(aptamer affinity magnetic beads,AAMB),将AAMB、孵育液、洗涤液和洗脱液预封装于试剂条中开发了AFB_1单样本前处理试剂盒,借助真菌毒素全自动净化仪实现了AFB_1前处理的自动化,使用超高效液相色谱仪对洗脱液中AFB_1的含量进行测定。通过优化磁珠粒径、适配体间接臂长度、适配体亲和磁珠用量、孵育液体积确定了AAMB的制备条件以及AFB_1单样本前处理试剂盒的使用条件,对比了手动和自动两种前处理方式下AAMB回收率的差异。在优化条件下,AFB_1的检出限(limit of detection,LOD)为0.6 ng/mL,玉米和小麦中低、中、高三个水平的加标回收率在92.8%~110.1%之间,日内精密度的相对标准偏差(relative standard deviation,RSD)小于5.1%,日间精密度的RSD为6.7%,具有良好的灵敏度、准确性和重复性;粮油基质(玉米、糙米、花生油和花生酱)中AFB_1成分国家有证标准物质的测定结果在其扩展范围内,具有良好的基质适用性。开发的单样本前处理试剂盒借助真菌毒素全自动净化仪仅需一步操作即可在20 min内自动完成10个样品的前处理,具有时间短、通量高、批次间差异小的优点,在真菌毒素定量检测方面具有良好的应用前景,为开发针对其它靶标的自动化前处理方法奠定了基础。

基于复合纳米材料比色/荧光双信号的黄曲霉毒素B_1检测

以黄曲霉毒素B_1(aflatoxin B_1,AFB_1)为检测目标物,使用二氧化硅纳米颗粒为载体富集谷胱甘肽和黄曲霉毒素适配体制备识别探针,二氧化锰纳米颗粒与石墨烯量子点偶联的复合纳米材料为底物,通过谷胱甘肽与底物的反应构建了一种比色和荧光双模信号输出的高灵敏便携式检测平台。在优化条件下,对本方法的检测性能及特异性进行研究,得到比色信号的回归方程为ΔA=-0.275-0.021lg C,检出限为2.732×10^(-12) g/m L;荧光信号的回归方程为ΔF=928.733+71.779lg C,检出限为1.667×10^(-12) g/m L,两种方法都具备良好检测特异性。将该方法用于牛奶、大米、麦片、酱油和白醋5种实际样品中AFB_1的检测,并与传统方法进行对比,本方法结果具有较高的准确度。

Dietary aflatoxin B1 induces abnormal deposition of melanin in the corium layer of the chicken shank possibly via promoting the expression of melanin synthesis-related genes

San-Huang chicken is a high-quality breed in China with yellow feather, claw and break. However, the abnormal phenomenon of the yellow shank turning into green shank of San-Huang chicken has been a concern, as it seriously reduces the carcass quality and economic benefit of yellow-feathered broilers. In this study, the cause of this abnormal green skin in shank was systematically investigated. Physiological anatomy revealed that the abnormal skin in shank was primarily due to the deposition of melanin under the dermis. After analyzing multiple potential causes such as heredity(pedigree and genetic markers), environment(water quality monitoring) and feed composition(mycotoxin detection), excessive aflatoxin B1(AFB1) in feed was screened, accompanied with a higher L-dihydroxy-phenylalanine(L-DOPA)(P<0.05) and melanin content(P<0.01). So it was speculated that excessive AFB1 might be the main cause of abnormal green skin in shank. Subsequently, the further results showed that a high concentration of AFB1(>170 μg kg–1)indeed induced the abnormal green skin in shank compared to the normal AFB1 content(<10 μg kg–1), and the mRNA levels of TYR, TYRP1, MITE, MC1R and EDN3 genes related to melanin deposition would significantly up-regulate(P<0.01) and the content and activity of tyrosinase(TyR) significantly increased(P<0.05). At the same time, the content of L-DOPA and melanin deposition also increased significantly(P<0.01), which also confirmed the effect of excessive AFB1 on melanin deposition in skin of shank. Results of additional experiments revealed that the AFB1's negative effect on melanin deposition in skin of shank could last for a longer time. Taken together, the results of this study explained the occurrence and possible mechanisms of the abnormal AFB1-related green skin in shank of chickens. Excessive AFB1 in diets increased the L-DOPA content and melanin abnormal deposition in the chicken shank possibly via promoting TyR content and activity, and the expression of melanin synthesis-related genes. Furthermore, our findings once again raised the alarm of the danger of AFB1 in the broiler production.

棉秸秆农药残留和重金属及真菌毒素检测分析

【目的】分析新疆6个棉花主产区棉秸秆的农药残留、重金属污染物和黄曲霉毒素B 1(aflatoxin B 1,AFB 1)等指标的含量,以期填补棉秸秆饲料化利用药物残留等基础数据缺失的问题。【方法】在新疆6个棉花种植区中各随机选一块棉田,设置前、中、后3个区域,每个区域设置5个1 m 2的样方,留茬15 cm,采集样方内所有棉秸秆,用剪枝钳剪碎混匀后按四分法采集1 kg样品,用于检测58种农药残留、AFB 1、脱氧雪腐镰刀菌烯醇、氟和5种重金属污染物含量。【结果】新疆6个棉花主产区样品中检出的农药残留分别仅为3、5、3、3、2和1种,大部分登记喷施的农药在棉秸秆样品中并未检出残留。检出的棉秸秆样品中氰戊菊酯、三唑磷、虫螨腈、毒死蜱、甲氰菊酯、吡唑醚菌酯、氯氰菊酯、马拉硫磷和啶虫脒的最大残留量为0.150、0.190、0.087、0.210、0.043、0.058、0.024、0.014和0.015 mg/kg,均低于食品安全标准GB 2763―2021中大米的限定值。棉秸秆样品中均检出了砷、铅、镉和铬这4种重金属污染物,最高含量分别为0.428、2.400、0.180和1.090 mg/kg,均低于饲料卫生标准GB 13078―2017中的限定值,符合饲料标准。棉秸秆样品中均未检出AFB 1和脱氧雪腐镰刀菌烯醇,检出氟的最高含量为20.67 mg/kg,低于饲料标准中的限定值。【结论】棉秸秆符合饲料卫生标准GB 13078―2017中农药残留、AFB 1、脱氧雪腐镰刀菌烯醇、氟和重金属污染物的限量标准,可以安全用作草食家畜的粗饲料。

伏马菌素B_(1)脱毒研究进展

伏马菌素B_(1)(FB_(1))是由镰刀菌产生的水溶性代谢产物,存在于镰刀菌污染了的谷物、油料作物、坚果、饲草和饲料中,是常见的真菌毒素之一。FB_(1)会对神经系统、呼吸系统、消化系统和生殖系统产生不同毒性作用,给农牧业造成不可估量的经济损失。如何对FB_(1)进行脱毒,以降低其毒性作用,是目前研究的热点。因此,本文对FB_(1)的物理脱毒、化学脱毒、生物脱毒及其应用进行综述,重点对常用于FB_(1)生物脱毒的菌株和酶及其脱毒效果、脱毒机制进行了深入探讨,以期为提高FB_(1)脱毒效率和开发新的FB_(1)脱毒方法提供参考和思路。

微嗜酸寡养单胞菌A2对摄食AFB_(1)污染日粮鹌鹑的保护效果

为研究微嗜酸寡养单胞菌(Stenotrophomonas acidaminiphila)A2对采食AFB_(1)日本鹌鹑的保护效果,本研究在含黄曲霉毒素B_(1)(AFB_(1))(95.34±2.62)μg/kg日粮中添加不同浓度(1 kg/t和2 kg/t)A2菌剂,饲喂30 d,通过检测鹌鹑的生产性能、器官指数、血清生化、肝肾抗氧化性能、蛋品质以及肝脏和蛋中的AFB_(1)含量等,评定A2对AFB_(1)造成危害的保护作用。结果表明:添加A2菌剂显著降低了AFB_(1)导致的鹌鹑料蛋比、肝脏和脾脏指数、血清中碱性磷酸酶(ALP)、谷丙转氨酶(ALT)、总甘油三酯(TG)等指标升高的负面影响;A2菌剂显著提高了AFB_(1)导致鹌鹑肝肾组织中总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GPx)水平降低的现象;A2菌剂显著提高了AFB_(1)导致的蛋壳重量、蛋壳强度和蛋形指数降低的负面影响;A2菌剂减少了肝脏和蛋中AFB_(1)的残留。且随着A2浓度增加,改善效果越明显。综上,S.acidaminiphila A2对AFB_(1)造成鹌鹑的负面影响有一定的改善作用。

维生素B_(6)对动脉粥样硬化小鼠血管内皮损伤的影响及作用机制

目的探讨维生素B_(6)(VB_(6))对动脉粥样硬化(AS)小鼠血管内皮损伤的影响及作用机制。方法将36只ApoE-/-小鼠随机分为对照组、AS组、VB_(6)组、AS+LiCl组、AS+VB_(6)组和AS+VB_(6)+LiCl组,每组6只。AS组、AS+LiCl组、AS+VB_(6)组和AS+VB_(6)+LiCl组小鼠高脂饮食12周建立AS模型;对照组和VB_(6)组小鼠常规饮食、正常饮水12周。12周后,对照组小鼠常规饮食,每日给予和VB_(6)组等体积的生理盐水灌胃;VB_(6)组小鼠常规饮食,每日灌胃给予VB_(6)(50 mg·kg^(-1));AS+LiCl组小鼠继续给予高脂饮食,每日灌胃给予LiCl(1 mg·kg^(-1));AS+VB_(6)组小鼠继续给予高脂饮食,每日灌胃给予VB_(6)(50 mg·kg^(-1));AS+VB_(6)+LiCl组小鼠继续给予高脂饮食,每日灌胃给予VB_(6)(50 mg·kg^(-1))和LiCl(1 mg·kg^(-1));6组小鼠均干预4周。干预结束后,采用酶联免疫吸附试验检测各组小鼠血清中一氧化氮(NO)、丙二醛(MDA)水平和超氧化物歧化酶(SOD)活性。苏木精-伊红染色观察各组小鼠胸主动脉组织形态,并计算AS斑块面积占血管总面积的百分比。离体血管环实验检测胸主动脉舒张率。免疫组织化学法检测胸主动脉中钠氢交换蛋白1(NHE1)表达。结果与对照组相比,AS组小鼠血清中NO水平和SOD活性显著下降,MDA水平显著升高(P<0.05);VB_(6)组与对照组小鼠血清中NO、MDA水平和SOD活性比较差异无统计学意义(P>0.05)。与AS组相比,AS+VB_(6)组小鼠血清中NO水平和SOD活性显著上升,MDA水平显著下降(P<0.05);AS+LiCl组、AS+VB_(6)+LiCl组与AS组小鼠血清中NO、MDA水平和SOD活性比较差异无统计学意义(P>0.05)。与AS+VB_(6)组相比,AS+VB_(6)+LiCl组小鼠血清中NO水平和SOD活性显著下降,MDA水平显著升高(P<0.05)。AS组小鼠AS斑块面积占血管总面积的百分比显著高于对照组(P<0.05);VB_(6)组与对照组小鼠AS斑块面积占血管总面积的百分比比较差异无统计学意义(P<0.05)。AS+VB_(6)组小鼠斑块面积占血管总面积的百分比显著低于AS组(P<0.05);AS+LiCl组、AS+VB_(6)+LiCl组与AS组小鼠AS斑块面积占血管总面积的百分比比较差异无统计学意义(P<0.05)。AS+VB_(6)+LiCl组小鼠AS斑块面积占血管总面积的百分比显著高于AS+VB_(6)组(P<0.05)。对照组小鼠血管内皮光滑平整,细胞排列整齐有序;AS组、AS+LiCl组和AS+VB_(6)+LiCl组小鼠的血管组织结构紊乱、血管内皮粗糙;VB_(6)组和AS+VB_(6)组小鼠的血管壁结构正常、血管内皮光滑、细胞排列有序。AS组小鼠乙酰胆碱(Ach)诱导的胸主动脉舒张率显著低于对照组(P<0.05);VB_(6)组与对照组小鼠Ach诱导的胸主动脉舒张率比较差异无统计学意义(P>0.05)。AS+VB_(6)组小鼠Ach诱导的胸主动脉舒张率显著低于AS组(P<0.05);AS+LiCl组、AS+VB_(6)+LiCl组与AS组小鼠Ach诱导的胸主动脉舒张率比较差异无统计学意义(P>0.05)。AS+VB_(6)+LiCl组小鼠Ach诱导的胸主动脉舒张率显著高于AS+VB_(6)组(P<0.05)。6组小鼠硝普钠诱导的胸主动脉舒张率比较差异均无统计学意义(P>0.05)。AS组小鼠胸主动脉中NHE1蛋白表达量百分比显著高于对照组(P<0.05);VB_(6)组与对照组小鼠胸主动脉中NHE1蛋白表达量百分比比较差异无统计学意义(P>0.05)。AS+VB_(6)组小鼠胸主动脉中NHE1蛋白表达量百分比显著低于AS组(P<0.05);AS+LiCl组、AS+VB_(6)+LiCl组与AS组小鼠胸主动脉中NHE1蛋白表达量百分比比较差异无统计学意义(P>0.05)。AS+VB_(6)+LiCl组小鼠胸主动脉中NHE1蛋白表达量百分比显著高于AS+VB_(6)组(P<0.05)。结论VB_(6)可通过抑制NHE1蛋白的表达来改善AS小鼠的血管内皮损伤。

以“维生素B_(1)质量分析”为例探索药物分析实验教学改革

以药物分析综合性实验《维生素B_(1)原料药及片剂的质量研究》为例,将新教学模式应用于药物分析综合实验项目,参照药物质量控制研究岗位的工作特点把项目培养方案与该岗位的职业需求相对接,设置岗位情景、明确岗位目标、增加岗位实例。最终提高学生的岗位适应能力和职业技能。以此,培养具备专业基础扎实、严格控制药品质量、具有良好药学职业道德的综合型药学人才。