木枣多糖诱导胃癌细胞MKN-45凋亡的作用机制

研究木枣多糖(ZMP)诱导胃癌细胞MKN-45凋亡及其可能的作用机制。采用MTT法测定肿瘤细胞存活率,DAPI/AOEB染色观察肿瘤细胞形态,比色法测定肿瘤细胞乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)的活性及丙二醛(MDA)含量,通过蛋白质免疫印迹(Western blot)方法检测细胞中抗凋亡蛋白(Bcl-2)和促凋亡蛋白(Bax,Cyt-c和Caspase-3)的表达。结果表明:木枣多糖可诱导胃癌细胞MKN-45凋亡,其作用可能与降低肿瘤细胞的SOD活性,增加MDA、LDH的含量有关。通过提高Bax蛋白表达和降低Bcl-2蛋白表达,促进细胞色素C从线粒体释放到细胞质中,激活Caspase-3,最终通过线粒体调节的内源性凋亡通路诱导胃癌细胞MKN-45凋亡。     

凝集素与TLRs信号通路的免疫调节作用

凝集素在自然界中分布广泛、种类众多,多种凝集素已经被分离提取出来。近年来,随着对凝集素研究的不断深入,凝集素的多种生物活性被发现。凝集素具有抗肿瘤、调节免疫、促进有丝分裂、抗病毒、抗病虫害等功能,尤其是抗肿瘤和调节免疫方面引起了学者们的广泛关注。Toll样受体(toll-like receptors,TLRs)存在于免疫细胞表面,在免疫调节过程中发挥重要的作用。本文介绍凝集素、概述TLRs信号通路以及两者之间的免疫调节作用,为凝集素在免疫调节、保健品等方面的开发与利用提供参考。     

山葵的风味物质及其功能应用研究进展

山葵的风味物质是植物组织中的硫葡糖苷经内源性芥子苷酶水解而产生具有辛辣风味的异硫氰酸酯.山葵的基本概况、风味前体及风味产生机理以及异硫氰酸酯的结构及降解方面的研究进展做一综述,对山葵的功能及其在食品行业中的应用进行了报道,并对山葵的发展前景进行了展望.     

食用菌功能活性蛋白通过TLRs信号通路的免疫调节作用研究进展

食用菌是含有多种生物活性物质的大型真菌,广泛分布于自然界中。许多研究表明,食用菌中的生物活性蛋白具有免疫调节、抗肿瘤、抗菌等功能,尤其是免疫调节活性备受关注。Toll样受体(toll-like receptors,TLRs)信号通路能将细胞外的信号传递到免疫系统中,激活细胞内丝裂原活化蛋白激酶和核因子-κB信号通路。本文综述了食用菌中免疫调节蛋白、凝集素、核糖体失活蛋白、糖肽等生物活性蛋白通过TLRs信号通路调节机体免疫的作用机制,为深入了解食用菌活性蛋白的功能活性,开发食用真菌保健食品或药品提供参考。     

异位嗅觉痕量胺相关受体研究进展

痕量胺相关受体（trace amine-associated receptors, TAARs）是一类G蛋白偶联受体,除TAAR1外,其余TAARs与嗅觉受体一样都在嗅觉上皮表达并发挥感知气味的作用。近年来,非嗅觉组织中同样发现TAARs高表达,提示TAARs可能存在重要的异位生理功能。事实上,相关研究证实内源性以及外源性特定痕量胺通过作用于不同的TAARs在非嗅觉组织中参与调节多种生理功能,表明TAARs有成为新的诊断和治疗靶点的潜力。本文系统介绍了异位嗅觉TAARs的表达、内源性以及外源性的配体、食物中的生物胺、异位嗅觉TAARs介导的信号通路以及生理和病理功能的现有研究,一方面为未来药物靶点开发、生理病理学研究提供新思路,另一方面也为食品中生物胺的生物活性研究提供新的研究方向。     

维生素E对镰刀菌毒素的解毒作用

维生素E具有广泛的生物学功能,可应用于美容、保健品及食品添加剂.镰刀菌可产生多种真菌毒素,如玉米赤霉烯酮、T-2毒素,对动物和人类产生严重毒害.本文综述了维生素E对镰刀菌毒素的毒素的解毒功能,保护生物体免受其侵害、或者降低毒害作用,及其可能的作用机理.     

维生素E对镰刀菌毒素的解毒作用

维生素E具有广泛的生物学功能,可应用于美容、保健品及食品添加剂.镰刀菌可产生多种真菌毒素,如玉米赤霉烯酮、T-2毒素,对动物和人类产生严重毒害.本文综述了维生素E对镰刀菌毒素的毒素的解毒功能,保护生物体免受其侵害、或者降低毒害作用,及其可能的作用机理.     

软骨多糖抑制H22肝癌细胞生长的作用及机制研究

探讨软骨多糖(CA)在体内抑制H22肝癌细胞生长的作用及其机制.以H22细胞腹水瘤模型为研究对象,设对照组﹑CA组两组,分别考察CA对各组小鼠的生活状态的影响.并且应用苏木素伊红(HE)染色、原位末端脱氧核苷酸转移酶标记法(TUNEL)、流式细胞术(FCM)及免疫荧光法对肿瘤细胞的生长和凋亡进行研究.CA可以在一定程度上促进H22细胞的凋亡,抑制肿瘤细胞的生长,延长小鼠的生存时间.并且,随着用药时间的延长,CA组的P21表达增强,而CyclinD1表达水平降低.软骨多糖有促进肿瘤细胞凋亡的作用,是一种新型的抗癌药物,具有广泛的应用前景.     

乳源性生物活性肽的研究进展

乳蛋白及乳制品具有多种营养功能.乳蛋白通过水解及发酵的乳制品中可产生多种生物活性多肽.它们对诸如消化系统,心血管,免疫和神经系统起着重要的作用.随着提取技术的改进和新技术的开发,越来越多的乳源性生物活性肤及其所具有的多种生理功能被认识,并逐渐被应用到功能性食品、药品和化妆品等领域.综述乳源性生物活性肽主要功能,提取方法及对人体健康的作用.     

食品中内源性甲醛的研究进展

甲醛是一种禁止在食品中添加和使用的高毒物质.大量调查研究表明许多食品(海产品、果蔬、乳制品等)中含有不同浓度的甲醛,由此引发各种食品中甲醛事件,使其成为消费者关注和学者研究的热点问题.现有研究证明,食品中的甲醛多是由食物本身自发产生的内源性甲醛.内源性甲醛的产生与调控机制研究对开发甲醛调控技术和提高食品安全性具有重要意义.本文综述了近年来食品中内源性甲醛的产生、调控机制和技术的研究进展,分析、提炼了科学问题,在此基础上提出该领域若干研究方向,以期为食品中内源性甲醛的进一步研究提供思路和参考.     

海地瓜岩藻聚糖硫酸酯对环磷酰胺损伤小鼠小肠粘膜的保护作用

目的探讨海地瓜岩藻聚糖硫酸酯,包括原糖及其不同分子量酶解产物(50、100、500kD)对环磷酰胺造成的小鼠小肠粘膜损伤的改善作用,幵对其机制进行探究。方法 60只Balb/c小鼠随机分成6组:空白对照组,环磷酰胺模型组,环磷酰胺损伤小鼠分别干预原糖及50、100、500kD酶解产物组,每组10只。实验周期为14 d,干预组分别ig给予50 mg/(kg·bw)海地瓜岩藻聚糖硫酸酯,第12和13 d给除空白对照组以外小鼠连续ip给予50 mg/(kg·bw)环磷酰胺。测定小鼠体重变化,器官指数变化;采用苏木精-伊红染色法检测小肠组织形态学变化;采用实时荧光定量PCR技术检测溶菌酶、黏蛋白(mucin2,Muc2)、干细胞标志物(leucine-rich repeat-containing G-protein coupled receptor5,Lgr5)mRNA表达水平,幵通过Toll样受体(toll-like receptors, TLRs)和髓样分化因子(myeloid differentiation factor88, MyD88)基因表达的变化探究其作用机制。结果 100 kD和50 kD组枀显著(P0.01)改善环磷酰胺造成的小鼠体重下降; 50 kD组显著(P0.05)提高绒毛长度和隐窝深度比值,改善小鼠小肠形态破坏; 100 kD组和50 kD组小肠溶菌酶、Muc2基因表达量显著高于Cy组,不同分子量的酶解产物均能显著提高Lgr5以及小肠TLRs (TLR-4, TLR-5, TLR-9)和MyD88的基因表达量,且50kD组的改善作用最好。结论酶解片段对化疗型小鼠小肠粘膜损伤的保护效果优于原糖,且50 kD效果最好,作用机制可能与对TLRs/MyD88信号通路的调节有关。     

Yoghurt consumption regulates the immune cells implicated in acute intestinal inflammation and prevents the recurrence of the inflammatory process in a mouse model

Crohn's disease and ulcerative colitis, two forms of inflammatory bowel disease, are important problems in industrialized countries. The complete etiology of these two diseases is still unknown but likely involves genetic, environmental, and immunological factors. The aim of the present work was to determine whether the anti-inflammatory effects reported for yoghurt in acute trinitrobenzene sulfonic acid-induced intestinal inflammation in mice also could prevent or attenuate the recurrent intestinal inflammation, thus maintaining remission. The innate response also was evaluated through participation of Toll-like receptors (TLRs) and the analysis of T-cell populations to determine the effects of yoghurt in an acute inflammatory bowel disease model. Yoghurt exerted a beneficial effect on acute intestinal inflammation by regulating T-cell expansion and modulating the expression of TLRs, with decrease of TLR4(+) and increase of TLR9(+) cells. The anti-inflammatory effect of yoghurt also was demonstrated in a recurrent inflammation model. Yoghurt administration during the remission phase prevented the recurrence of inflammation without producing undesirable side effects. The yoghurt effect may be mediated by increased interleukin 10 production and changes in intestinal microbiota.     

应用于肉品嫩化的组织蛋白酶的研究进展

大量研究表明,成熟嫩化过程是肌肉内源蛋白水解酶的作用所致。组织蛋白酶是其中一个重要的内源蛋白,可以水解肌原纤维。本文简要介绍了溶酶体中的组织蛋白酶,以及其稳定性和在骨骼肌中的表达特性。并且就组织蛋白酶的分类、影响其活性的因素、在肉嫩化中的作用、分离提纯、活性测定方法及应用前景等作了介绍。     

Effect of interferon-gamma on the production of tumor necrosis factor during acute Escherichia coli mastitis.

The effects of recombinant interferon-gamma on the production of tumor necrosis factor in 10 dairy cows with Escherichia coli mastitis were determined. Prophylactic administration of recombinant interferon-gamma prior to the experimental E. coli challenge was effective in modifying the production of endogenous tumor necrosis factor during acute stages of disease. Elevated tumor necrosis factor concentrations were especially evident in cows that developed severe clinical symptoms and eventually died from endotoxemia. These results indicate that both milk and sera tumor necrosis factor concentrations are associated closely with the manifestation of peracute signs of coliform mastitis and are important factors contributing to morbidity and mortality of endotoxic shock. Pretreatment of cows with recombinant interferon-gamma possibly may down-regulate the generation of this potent endogenous inflammatory mediator within infected quarters. Controlling severe inflammation with recombinant interferon-gamma may prevent the tremendous loss in milk production and death that often accompany acute coliform mastitis during the periparturient period.     

Milk protein gene expression in the rat mammary gland

For the studies of the expression of milk proteins during the functional development of the rat mammary gland and in mammary tumor MTW9, milk proteins were purified, their mRNAs isolated, and the cDNA sequences complementary to these mRNAs cloned in E. coli cells. Results of such studies show: (1) rat α‐LA is unique in that it is larger than any known α‐LAs and is glycosylated; (2) rat milk contains unique whey phosphoproteins not found in other milks; (3) more than one plasmid DNA with differences in the restriction maps have been identified for several of these milk proteins, suggesting eithera presence of a family of genes or allelic differences for these proteins; (4) the expression of individual milk proteins is dependent on the functional stage of the gland; (5) there is an inverse relationship between the expression of milk proteins and the methylation of their gene sequences; (6) mammotrophic hormones required for synthesis and stability of milk proteins and their mRNAs, when withdrawn arrest the synthesis of α‐LA in the mammary tumor MTW9 at 6 hr or earlier of withdrawal but without any measurable effect on other proteins of the tumor.     

Dietary N‐Glycans from Bovine Lactoferrin and TLR Modulation

1 Scope

Bovine lactoferrin (bLF) is an ingredient of food supplements and infant formulas given its antimicrobial and antiviral properties. We modified bLF enzymatically to alter its N‐glycosylation and to isolate the glycan chains. The aims of this study include (1) to evaluate whether such derivates induce responses via pattern recognition receptors namely Toll‐like receptors (TLRs) and (2) to relate those responses to their different glycosylation profiles.

2 Methods and results

The unmodified and modified bLF fractions are incubated with reporter cell lines expressing pattern recognition receptors. Afterwards, we screen for TLRs and analyze for nuclear factor kappa—light‐chain enhancer of activated B cells (NF‐κB) activation. Activation of reporter cell lines show that signaling is highly dependent on TLRs. The activation pattern of bLF is reduced with the desialylated form and increased with the demannosylated form. In reporter cells for TLR, bLF activate TLR‐4 and inhibit TLR‐3. The isolated glycans from bLF inhibit TLR‐8. TLR‐2, TLR‐5, TLR‐7, and TLR‐9 are not significantly altered.

3 Conclusion

The profile of glycosylation is key for the biological activity of bLF. By understanding how this affects the human defense responses, the bLF glycan profile can be modified to enhance its immunomodulatory effects when used as a dietary ingredient.     

Conjugated linoleic acid synthesis-related protein proteasome subunit α 5 (PSMA5) is increased by vaccenic acid treatment in goat mammary tissue

This study was conducted to identify proteins associated with the endogenous synthesis of conjugated linoleic acid (CLA) from trans-vaccenic acid (TVA; trans-11 C18:1, a precursor for CLA endogenous synthesis) in mammary tissues. Six lactating goats were divided into 2 groups. One group was given an intravenous bolus injection of TVA (150mg) twice daily over 4 d; the other group received saline injections. Treatment with TVA increased the concentration of cis-9,trans-11 CLA and TVA in goat milk. Additionally, TVA treatment increased the expression of stearoyl-CoA desaturase (SCD) in mammary tissue. Using 2-dimensional gel electrophoresis and electrospray ionization quadrupole time-of-flight mass spectrometry, 3 proteins affected by infusions of TVA were identified. Proteasome (prosome, macropain) subunit α type 5 (PSMA5) was upregulated, whereas peroxiredoxin-1 and translationally controlled tumor protein 1 were downregulated in TVA-treated animals compared with the vehicle-injected controls. Only the effect of TVA on PSMA5 could be confirmed by Western blot analysis. To further explore the regulation of PSMA5 in mammary epithelial cells when TVA is converted into CLA, we used a differentiated bovine mammary epithelial cell line treated with TVA for 6h. Changes in cis-9,trans-11 CLA concentrations and mRNA expression patterns of both SCD and PSMA5 were monitored. The concentration of cis-9,trans-11 CLA increased after TVA treatment. The mRNA expression level of PSMA5 was significantly elevated to 6h, but SCD mRNA expression only increased in 2h after TVA treatment. These results indicate that PSMA5 is highly expressed in goat mammary tissue and bovine mammary epithelial cells when TVA is converted into CLA. Our data suggest that PSMA5 protein is associated with CLA biosynthesis in mammary tissue.     

6-苄氨基嘌呤减缓鲜切西兰花的衰老机理分析

为研究6-苄氨基嘌呤（6-benzylaminopurine,6-BA）调控采后西兰花衰老的可能机理,以鲜切西兰花为材料,考察了30 mg/L 6-BA处理对鲜切西兰花内源6-BA含量、总叶绿素含量、菌落总数、乙烯释放量、衰老相关基因表达、乙烯合成相关酶活性及其基因表达的影响。结果表明：6-BA处理可有效延缓西兰花总叶绿素的降解,抑制其菌落总数上升;随着贮藏时间的延长,与对照西兰花内源6-BA含量不断下降不同,外源6-BA处理则维持了贮藏后期组织内较高的6-BA含量,但经煮熟后,处理和对照组的内源6-BA含量均大幅度下降;6-BA处理下调了叶绿素酶2、半胱氨酸蛋白酶5和富含脯氨酸蛋白基因的表达,延缓了叶绿素a/b结合蛋白1基因表达的下降;6-BA处理降低了乙烯合成酶活性及其基因的表达,显著抑制了西兰花的乙烯释放量。总之,外源6-BA维持了鲜切西兰花贮藏后期组织内较高的内源6-BA水平,从而抑制了乙烯的生成,最终减缓了西兰花的衰老进程。     

Apoptosis of bovine ovarian surface epithelial cells by Fas antigen/Fas ligand signaling

Ovarian surface epithelial cells (OSEs), a single layer of cells that cover the surface of the ovary, undergo turnover at the site of follicular rupture at ovulation. Greater than 90% of ovarian cancers arise from the OSEs. The objective of this study was to determine whether OSEs have the capacity to regulate their own demise through expression of Fas antigen (Fas) and Fas ligand (FasL) and activation of Fas-mediated apoptosis. In initial experiments, primary cultures of bovine OSEs responded to treatment with recombinant FasL by undergoing apoptosis. The percentage of cell death was not affected by the presence or absence of serum in the media or by co-treatment with interferon-gamma, a treatment shown to potentiate Fas-mediated apoptosis in a number of cell types. Subsequent experiments tested the ability of stress-inducing drugs, anisomycin and daunorubicin, to promote apoptosis by stimulating an endogenous Fas-FasL pathway in OSEs. Treatment with FasL, anisomycin or daunorubicin induced cell death and this was suppressed by co-treatment with a peptide inhibitor of caspases, ZVAD. Treatment with anisomycin or daunorubicin in the presence of ZVAD increased expression of FasL mRNA and protein but did not alter expression of Fas mRNA or protein. Treatment of OSEs with a recombinant protein that blocks interaction of FasL with Fas (Fas:Fc) reduced apoptosis in response to anisomycin and daunorubicin, indicating that drug-induced apoptosis was mediated at least partially through endogenous Fas-FasL interactions. In summary, OSEs undergo apoptosis in response to stress-inducing drugs through activation of an endogenous Fas pathway.