Evaluation and application of a milk antibody ELISA for assessing the prevalence and incidence of bovine tuberculosis in dairy herds in Hubei Province,China

Bovine tuberculosis(bTB)is a chronic zoonotic disease that is endemic in China.Current in-vitro tests for bTB are mainly based on blood assays.Collection of samples results in some stress to the sampled cattle and associated economic losses for the herd owner.This study was designed to investigate the relationship between milk and serum antibody tests for bTB in dairy cows using 85 cows with milk and corresponding blood samples.Totally 4,395 milk samples were used to assesse the apparent(test)prevalence and incidence of bTB using the milk antibody ELISA.The association between levels of bTB milk antibody and milk quality was also evaluated.Milk and serum antibody tests showed a good correlation with a 87.5%(95%CI:61.7%,98.4)positive agreement and 98.7%(95%CI:95.4,99.8)negative agreement.The animal level lactoprevalence ranged from 0.3%(95%CI:0,1.2)to 33.3%(95%CI:26.6,40.6)in different farms and the incidence rate ranged from 0 head/cow-month(95%CI:0,0.02)to 0.04 head/cow-month(95%CI:0.02,0.07).Twenty percent of sampled farms met the criteria for bTB control in China.The prevalence on large-scale farms was lower(p<0.001)than on small farms.The bTB milk antibody levels had a negative correlation with milk yield and a positive correlation with somatic cell count(SCC),milk protein percentage(MPP)and percentage of total solids(TS).According to this research,milk ELISA could be used as a supplement of blood samples to assist in the surveillance for bTB and for alerting control and eradication of bTB.

HPLC Analysis of α-lactalbumin and β-lactoglobulin in Bovine Milk with C_4 and C_(18) Column

Reversed-phase high-performance liquid chromatography （RP-HPLC） method with C4 column and C18 column for analyzing β-lactoglobulin and α-lactalbumin in bovine milk was developed and the performance and characteristic of two columns were compared. Shiseido Proteonavi C4 column （250 mm×4.6 mm×5μm） and Shiseido CAPCELL PAK SG 300 C18 column （250 mm× 4.6 mm×5 μm） were used in the experiment. Phase A was composed of 0.1% （V/V） trifluoroacetic acid （TFA） in ultrapure water and Phase B （organic phase） was composed of 0.1% TFA in acetonitrile. Gradient elution was taken. Flow rate was 1 mL min-1. The detection wavelength was 215 nm. The injection volume was 20 μL and the column temperature was 30℃. The results showed that linear relationship was good and recovery of α-lactalbumin and β-lactoglobulin was 86.12%-104.38%, C18 column had stronger ability to resist acid and more stable, and the method with C4 column had excellent sensitivities and good separation.

Efficient reduction ofβ-lactoglobulin allergenicity in milk using Clostridium tyrobutyricum Z816

Milk allergy is one of the most common food allergies,affecting 6%of young children,andβ-lactoglobulin(β-LG)is the main milk allergen.Clostridium tyrobutyricum Z816 was selected for the degradation ofβ-LG,which was successfully reduced by about 90%using permeabilized bacteria under the optimized conditions.The hydrolyzed peptides were identified by liquid chromatography-tandem mass spectrometry(LC-MS/MS)and analyzed by molecular modeling,which indicated that C.tyrobutyricum Z816 could effectively degrade the antigenic epitopes ofβ-LG.Finally,the concentration and digestibility ofβ-LG in actual samples was quantified using enzyme-linked immunosorbent assay(ELISA)and gastrointestinal digestion simulation experiments.The results showed more than 92%ofβ-LG in actual samples was hydrolyzed,and the gastric and total digestibility of whey protein isolate(WPI)was improved by 85.96%and 64.51%,respectively.Therefore,C.tyrobutyricum Z816 offers an effective method to degradeβ-LG and reduce the occurrence of milk allergies,which has great significance for the development of hypoallergenic dairy products.

Bta-miR-34b controls milk fat biosynthesis via the Akt/mTOR signaling pathway by targeting RAI14 in bovine mammary epithelial cells

Background:The biosynthesis of milk fat affects both the technological properties and organoleptic quality of milk and dairy products.MicroRNAs(miRNAs)are endogenous small non-coding RNAs that inhibit the expression of their mRNA targets and are involved in downstream signaling pathways that control several biological processes,including milk fat synthesis.miR-34b is a member of the miR-34 miRNA cluster,which is differentially expressed in the mammary gland tissue of dairy cows during lactation and dry periods.Previous studies have indicated miR-34b is a potential candidate gene that plays a decisive role in regulating milk fat synthesis;therefore,it is important to focus on miR-34b and investigate its regulatory effect on the biosynthesis of milk fat in bovine mammary epithelial cells(BMECs).Results:In this study,elevated miR-34b levels reduced milk fat synthesis,upregulated 1,999 genes,and downregulated 2,009 genes in BMECs.Moreover,Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis of differentially expressed genes suggested that miR-34b may play an inhibitory role in milk fat synthesis via the protein kinase B(Akt)/mammalian target of rapamycin(mTOR)signaling pathway by reducing phosphorylation levels.Notably,the mTOR activator MHY1485 rescued the inhibitory effect of miR-34b.Furthermore,we demonstrated that retinoic acid-induced protein 14(RAI14)is a target of miR-34b via TargetScan and immunofluorescence assays.RAI14 mRNA and protein levels were significantly decreased by the miR-34b mimic and increased by the miR-34b inhibitor.Moreover,the reduction in RAI14 levels led to the inhibition of the Akt/mTOR signaling pathway.Conclusions:Overall,our results identified a miR-34b-RAI14-Akt/mTOR regulatory network,while also providing a theoretical basis for the molecular breeding of dairy cows.

Dietary polyphenols reduced the allergenicity ofβ-lactoglobulin via non-covalent interactions:a study on the structure-allergenicity relationship

Studies showed that complexation of polyphenols with milk allergens reduced their immunogenic potential.However,the relationship between structures of polyphenols and their hypoallergenic effects on milk allergens in association with physiological and conformational changes of the complexes remain unclear.In this study,polyphenols from eight botanical sources were extracted to prepare non-covalent complexes withβ-lactoglobulin(β-LG),a major allergen in milk.The dominant phenolic compounds bound toβ-LG with a diminished allergenicity were identified to investigate their respective role on the structural and allergenic properties ofβ-LG.Extracts from Vaccinium fruits and black soybeans were found to have great inhibitory effects on the IgE-and IgG-binding abilities ofβ-LG.Among the fourteen structure-related phenolic compounds,flavonoids and tannins with larger MWs and multi-hydroxyl substituents,notably rutin,EGCG,and ellagitannins were more potent to elicit changes on the conformational structures ofβ-LG to decrease the allergenicity of complexedβ-LG.Correlation analysis further demonstrated that a destabilized secondary structure and protein depolymerization caused by polyphenol-binding were closely related to the allergenicity property of formed complexes.This study provides insights into the understanding of structure-allergenicity relationship ofβ-LG-polyphenol interactions and would benefit the development of polyphenol-fortified matrices with hypoallergenic potential.

Characterization of <i>Lactobacillus</i>Strains Isolated from Bovine Raw Milk for Probiotic and Technological Properties

One hundred strains isolated from bovine raw milk, obtained from different farms, were subjected to different in vitro stress typical of gastrointestinal tract. Twelve strains were able to tolerate pepsin at pH 2, pancreatin and bile salts (0.3%). These bacteria were identified using 16S rRNA gene sequencing. Eight isolates were Lactobacillus plantarum and four were Lactobacillus fermentum. They were not able to degrade mucin and they were γ-haemolytic. All strains had antibacterial activity against Staphylococcus aureus, Listeria monocytogenes and Salmonella thyphimirium. However, only six strains inhibited Escherchia coli. All these showed ability for autoaggregation and/or hydrophobicity properties. They were also characterized in respect to their technological properties. Important acidification and low proteolytic and lipolytic capacities were detected for all strains. In addition, they were able to produce exopolysaccharides and grow at hot and cold temperatures. These bacteria may be used further for manufacturing of functional foods and confirming their suitability as probiotic starter cultures.

Effect of Carbonation on Microbiologic Parameters of Refrigerated Bovine Raw Milk

This study evaluated the effect of carbon dioxide addition on microbiological quality during refrigerated storage of raw milk collected in Curitiba city, Brazil. A three factor-two level full factorial design was used to investigate the effect of the pH （5.8-6.4）, storage time （0-10 days） and storage temperature （5-10 ℃）, on the responses, namely, mesophiles, psychrotrophs, lipolytic psychrotrophs and proteolytic psychrotrophs counts. Results showed that increase in pH and storage time had significant effect on the microbial count. No significant effect of storage temperature was observed for all the microorganisms studied. All responses were well predicted by selected mathematical models, as denoted by coefficient of determination above 0.95.

Lactogenic hormones alter cellular and extracellular microRNA expression in bovine mammary epithelial cell culture

Background： Bovine milk contains not only a variety of nutritional ingredients but also microRNAs （miRNAs） that are thought to be secreted by the bovine mammary epithelial cells （BMECs）. The objective of this study was to elucidate the production of milk-related miRNAs in BMECs under the influence of lactogenic hormones. Results： According to a microarray result of milk exosomal miRNAs prior to cellular analyses, a total of 257 miRNAs were detected in a Holstein cow milk. Of these, 18 major miRNAs of interest in the milk were selected for an expression analysis in BMEC culture that was treated with or without dexamethasone, insulin, and prolactin （DIP） to induce a lactogenic differentiation. Quantitative polymerase chain reaction （qPCR） results showed that the expressions of miR-21-Sp （P = 0.005）, miR-26a （P = 0.016）, and miR-320a （P = 0.011） were lower in the DIP-treated cells than in the untreated cells. In contrast, the expression of miR-339a （P-- 0.017） in the cell culture medium were lower in the DiP-treated culture than in the untreated culture. Intriguingly, the miR-148a expression in cell culture medium was elevated by DIP treatment of BMEC culture （P = 0.018）. The medium-to-cell expression ratios of miR- 103 （P = 0.025）, miR-148a （P 〈 0.001）, and miR-223 （P = 0.013） were elevated in the DIP-treated BMECs, suggesting that the lactogenic differentiation-induced secretion of these three miRNAs in BMECs. A bioinformatic analysis showed that the miRNAs down-regulated in the BMECs were associated with the suppression of genes related to transcriptional regulation, protein phosphorylation, and tube development. Conclusion： The results suggest that the miRNAs changed by lactogenic hormones are associated with milk protein synthesis, and mammary gland development and maturation. The elevated miR-148a level in DIP-treated BMECs may be associated with its increase in milk during the lactation period of cows.

A metabolomics approach for monitoring thermal processing temperature of bovine milk using ultra-performance liquid chromatography tandem Q-Exactive mass spectrometry and multivariate data analysis

Due to the lack of effective assessment method,overheated milk commodities are often marketed as pasteurized milk on the market,which was sold in high price by fraud.Thus,this article aims to establish an approach based on metabolomics to monitor thermal processing temperature of bovine milk.Metabolomics data of bovine milk samples heated at temperatures ranging from 60℃to 150℃were achieved by ultra-performance liquid chromatography-high-resolution mass spectrometry(UPLC-HRMS)platform,followed by multivariate data analysis.A regular variation pattern of chemical composition as temperature rises was pictured,furthermore.N^(∈)carboxymethyl lysine(CML),N^(∈)-carboxyethyl lysine(CEL),pentosidine.pvrraline and lysinoalanine(LAL)were identified as 5 of the most contributed compounds to discriminate pasteurized and ultra-high-temperature(UHT)milk.By the comprehensive study on their content changes,we concluded that the optimal temperature range was 90-100℃for the generation of CML and CEL in this experiment,moreover.110~120℃for LAL.S0~100℃for pentosidine and 130-140℃for pvrraline.Finally,a predicted rule to discriminate pasteurized and UHT milk was preliminarily established based on the ratios of CML/CEL.CEL/pentosidine and CML/pentosidine.which could be applied in food labelling authentication of commercial bovine milk after further validation.

Identification of Bovine Casein Phosphorylation Using Titanium Dioxide Enrichment in Combination with Nano Electrospray Ionization Tandem Mass Spectrometry

Protein phosphorylation is an important post-translational modification that regulates milk protein structure and function.The objective of this study was to analyze the presence of phosphorylated casein.Bovine milk proteins were first separated by SDS polyacrylamide gel electrophoresis.After in gels digestion and extraction,phosphorylated peptides were enriched by titanium dioxide and identified by ultra performance liquid chromatography coupled with nano electrospray ionization tandem mass spectrometry.This method ensured the identification of 20 phosphorylated peptides,including 7 phosphorylated forms of α_s1-casein,8 α_s2-casein,and 5 β-casein.Eight phosphorylated sites derived from 3 α_s1-caseins,3 α_s2-caseins,and 2 β-caseins were also identified,and localized on residues Ser^61,Ser^63 and Ser^130 in α_s1-casein;Thr^145,Ser^146 and Ser^158 in α_s2-casein;and Ser^50 and Thr^56 in β-casein.These findings provide valuable information for investigating casein phosphorylation of the bovine milk.

Bovine <i>β</i>-casein: Detection of two single nucleotide polymorphisms by bidirectional allele specific polymerase chain reaction (BAS-PCR) and monitoring of their variation

Due to the functional importance of bovine milk protein polymorphisms, their correct discrimination is of great interest both from a scientific and practical point of view. Nowadays a large number of commercial platforms are available for semiautomated or fully automated SNP geno-typing. However, in some cases the use of simple and rather cheap methods is an effective tool to be implemented within one’s own laboratory for the routine analysis of a specific SNP. The present paper describes two simple tests based on the bidirectional allele-specific polymerase chain reaction (BAS-PCR) developed for the identification of β-casein (CSN2) B and I genetic variants. The practical application of the two methods on a panel of 84 Italian Brown bulls and 100 Italian Friesian cows is also discussed, including the biological significance of the two genetic variants and the importance of taking their occurrence into account when linkage analyses are performed on milk functional properties. A combined system for analysing milk protein variants by isoelectrofocusing (IEF) and the BAS-PCR assay developed for CSN2*I is described.

Fabrication and evaluation of a portable and reproducible quartz crystal microbalance immunochip for label-free detection ofβ-lactoglobulin allergen in milk products

In this study,a label-free,portable and reproducible immunochip based on quartz crystal microbalance(QCM)was developed for the qualitative detection ofβ-lactoglobulin(β-LG),an allergen,in milk products.Experimental parameters in the fabrication and regeneration procedure such as pH of the coupling microenvironment,amount of anti-β-LG antibody and regeneration reagent were optimized in detail.Under optimal conditions,the proposed QCM immunochip exhibited good recognition of β-LG,with a calibration curve of ΔF=12.877 C_(β-LG)^(0.4809)(R^(2)=0.9982)and limit of detection of 0.04μg/mL.Additionally,this portable QCM immunochip had good stability,high specificity,and no obvious cross-reaction to three other milk proteins(α-casein,α-lactalbumin,and lactoferrin).It could compete a qualitative measurement within5 min,and could be reused at least ten times.In the β-LG analysis of actual milk samples,the developed QCM immunochip yielded reliable and accurate results,which correlated strongly with those from the standard HPLC method(R^(2)=0.9969).Thus,the portable,stable,and reproducible QCM immunochip developed in this study allowed the rapid,cost-effectively and sensitively measure theβ-LG in milk products.

玉米赤霉烯酮对奶牛乳腺上皮细胞生长和乳脂合成相关基因表达的影响

旨在探索不同浓度玉米赤霉烯酮(ZEN)对奶牛乳腺上皮细胞(MAC-T)生长和乳脂合成相关基因表达的影响。首先,用不同剂量ZEN处理MAC-T细胞36 h,血细胞计数板统计细胞数量,染色并分析细胞凋亡与坏死情况,筛选ZEN添加的合适剂量;接着,试剂盒检测ZEN对MAC-T细胞中活性氧(ROS)以及线粒体膜电位的影响;最后,利用实时荧光定量PCR(RT-qPCR)技术,分析ZEN对MAC-T细胞增殖、凋亡、氧化应激和乳脂合成相关基因表达的影响。结果表明,低剂量ZEN(0.01~1.00μmol/L)有促进MAC-T生长的趋势,而高剂量ZEN(5.00~10.00μmol/L)显著降低MAC-T细胞数量;0.10μmol/L ZEN对MAC-T中ROS和线粒体数量无明显影响,但10.00μmol/L ZEN显著增加了MAC-T中ROS水平,降低了线粒体数量;RT-qPCR结果表明,0.10μmol/L ZEN显著促进增殖基因(CDK1、CCND2)、抗氧化基因(DHODH、GPX4)和抗凋亡基因(BCL-2)表达,但同时提高了凋亡基因(CAS-3、BAX)表达量;10.00μmol/L ZEN显著抑制增殖基因(PCNA、CDK1、CCND2)、抗氧化基因(DHODH、GPX4、AIFM2)和抗凋亡基因(BCL-2)表达,但显著促进凋亡基因(CAS-3、BAX)表达;值得注意的是,0.10μmol/L ZEN显著促进了乳脂合成相关基因(PPARγ、FASN、JAK-2),但10.00μmol/L ZEN显著抑制了这些基因表达。上述结果提示,不同浓度ZEN对MAC-T细胞的作用存在差异:0.10μmol/L ZEN可以促进MAC-T细胞生长和乳脂合成相关基因表达的同时,也会诱导凋亡基因表达;10.00μmol/L ZEN会诱导MAC-T细胞氧化应激、降低线粒体数量,抑制增殖、抗氧化、抗凋亡和乳脂合成相关基因表达,同时促进凋亡基因表达,导致细胞死亡。

乳源外泌体对微生物的作用

外泌体是纳米级(直径40~160 nm)的胞外囊泡,在细胞信号转导、免疫应答和抗原递呈过程中发挥作用,并存在于多种体液,包括血清、唾液、尿液、脑脊液和乳液等。乳外泌体携带蛋白质、miRNA等多种功能分子,很多与人体免疫功能相关。摄取乳液后,乳外泌体中的内容物可被人体肠道吸收,从而发挥健康作用。本文总结国内外有关乳源外泌体与微生物关系的研究报道以及本团队的研究成果,阐述外泌体的生物发生过程,主要组成成分,外泌体与病原微生物感染的关系以及乳外泌体对肠道微生物的作用,为研究乳外泌体对人体的营养和健康功效提供参考。

宁夏地区牛乳肠球菌耐药性分析

【目的】了解宁夏地区奶牛正常乳汁和患乳腺炎乳汁中肠球菌的分布规律及其耐药特征,为宁夏地区奶牛乳腺炎疾病的抗菌药物合理使用提供参考。【方法】对宁夏地区16个规模化奶牛养殖场近3年来1154份乳汁样品(正常乳汁383份,患乳腺炎乳汁771份)进行肠球菌分离,采用形态学观察和生化试验对分离所获的496株肠球菌进行鉴定,通过K-B药敏纸片扩散法测定分离肠球菌菌株对青霉素(PG)、头孢唑林(CFZ)、庆大霉素(GEN)、四环素(TET)、红霉素(EM)、林可霉素(LCM)、链霉素(SM)和万古霉素(VCA)等8种药物的敏感性,并使用PCR方法对分离肠球菌菌株进行四环素类药物耐药基因(tetA、tetB、tetC、tetM)、大环内酯类药物耐药基因(mecA、ermA、ermB、ermC)以及林可胺类药物耐药基因(lsaA、lsaE、lnuG、lnuA)检测。【结果】从1154份乳样中共分离得到496株肠球菌,经鉴定分属6种肠球菌,分别是屎肠球菌、海氏肠球菌、粪肠球菌、蒙氏肠球菌、耐久肠球菌和鹑鸡肠球菌。其中屎肠球菌305株,占分离菌株总数的61.5%;海氏肠球菌124株,占分离菌株总数的25.0%;粪肠球菌27株,占分离菌株总数的5.4%;蒙氏肠球菌21株,占分离菌株总数的4.2%;耐久肠球菌15株,占分离菌株总数的3.0%;鹑鸡肠球菌4株,占分离菌株总数的0.8%。临床分离菌株对林可霉素、四环素、红霉素的耐药率分别达到95.8%,82.7%和80.2%,尤以耐7种药物的菌株为主,达230株(占耐药菌株的46.4%),最常见的耐药谱为PG+CFZ+GEN+TET+EM+LCM+SM。正常乳汁中分离的菌株主要为海氏肠球菌(检出率为73.8%),对林可霉素的耐药率最高(94.5%);患乳腺炎乳汁中分离的菌株主要为屎肠球菌(检出率为89.5%),对四环素的耐药率最高(97.0%)。496株临床肠球菌中有488株检测出携带耐药基因,检出率为98.4%;检测出乳源肠球菌不携带tetA、tetB、tetC、mecA、lnuG和lnuA耐药基因;携带ermA、ermB、ermC、tetM、lsaA和lsaE耐药基因,其携带率分别为51.0%,80.3%,33.2%,88.1%,41.6%和74.4%;最常见耐药基因谱为ermA+ermB+tetM+lsaE+lsaA。【结论】宁夏地区奶牛乳汁中肠球菌耐药性严重,且具有多重耐药性特征,给公共卫生带来潜在危害,应引起高度重视。

Hexokinase 1 and 2 mediates glucose utilization to regulate the synthesis of kappa casein via ribosome protein subunit 6 kinase 1 in bovine mammary epithelial cells

Glucose plays a vital part in milk protein synthesis through the mTOR signaling pathway in bovine mammary epithelial cells(BMEC).The objectives of this study were to determine how glucose affects hexokinase(HK)activity in BMEC and investigate the regulatory effect of HK in kappa casein(CSN3)synthesis via the mechanistic target of rapamycin complex 1(mTORC1)signaling pathway in BMEC.For this,HK1 and HK2 were knocked out in BMEC using the CRISPR/Cas9 system.The gene and protein expression,glucose uptake,and cell proliferation were measured.We found that glucose uptake,cell proliferation,CSN3 gene expression levels,and expression of HK1 and HK2 increased with increasing glucose concentrations.Notably,glucose uptake was significantly reduced in HK2 knockout(HK2KO)BMEC treated with 17.5 mM glucose.Moreover,under the same glucose treatment conditions,the proliferative ability and abundance of CSN3 were significantly diminished in both HK1 knockout(HK1KO)and HK2KO BMEC compared with that in wild-type BEMC.We further observed that the phosphorylation levels of ribosome protein subunit 6 kinase 1(S6K1)were reduced in HK1KO and HK2KO BMEC following treatment with 17.5 mM glucose.As expected,the levels of glucose-6-phosphate and the m RNA expression levels of glycolysis-related genes were decreased in both HK1KO and HK2KO BMEC following glucose treatment.These results indicated that the knockout of HK1 and HK2 inhibited cell proliferation and CSN3 expression in BMEC under glucose treatment,which may be associated with the inactivation of the S6K1 and inhibition of glycolysis.

竹叶黄酮对奶牛乳腺上皮细胞氧化损伤的缓解作用及对乳脂合成的影响

本试验旨在探究竹叶黄酮(BLF)对奶牛乳腺上皮细胞(BMECs)氧化损伤的缓解作用及对乳脂合成的影响。以BMECs为研究对象,进行如下操作:对照组1是将细胞接种于不添加任何物质的维持培养基中培养24 h;损伤组是将细胞接种于含800μmol/L过氧化氢(H_(2)O_(2))的维持培养基中处理8 h;对照组2是将细胞接种于含80μg/mL BLF的维持培养基中培养24 h;保护组是将细胞接种于含80μg/mL BLF的维持培养基中培养24 h后,更换含800μmol/L H_(2)O_(2)的维持培养基中继续处理8 h。应用试剂盒检测细胞内抗氧化指标,实时荧光定量PCR方法检测细胞内抗氧化、凋亡和乳脂合成相关基因的mRNA相对表达量,免疫印迹法检测乳脂合成相关蛋白的表达量。结果显示:1)与损伤组相比,保护组细胞内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性显著升高(P<0.05),丙二醛(MDA)含量显著降低(P<0.05)。2)与对照组1相比,损伤组细胞内活性氧(ROS)含量显著提升(P<0.05),BLF预处理可以显著抑制受氧化损伤的细胞内ROS产生(P<0.05)。3)与损伤组相比,保护组细胞内凋亡基因B细胞淋巴瘤/白血病-2相关X蛋白(Bax)和半胱氨酸天冬氨酸蛋白酶3(Caspase 3)的mRNA相对表达量显著降低(P<0.05),抗凋亡基因B淋巴细胞瘤2(Bcl2)的mRNA相对表达量显著升高(P<0.05),抗氧化基因血红素加氧酶-1(HO-1)、醌氧化还原酶1(NQO1)和核转录因子E2相关因子2(Nrf2)的mRNA相对表达量显著升高(P<0.05)。4)与对照组1相比,损伤组细胞内脂滴(LDs)含量减少,保护组细胞内LDs含量有所增加;保护组细胞内甘油三酯(TGs)含量虽未恢复到正常水平,但与损伤组相比差异显著(P<0.05)。5)与损伤组相比,保护组细胞内乳脂合成相关基因乙酰辅酶A羧化酶α(ACACA)、乙酰辅酶A合成酶2(ACSS2)、脂肪酸结合蛋白3(FABP3)、脂肪酸合成酶(FASN)、过氧化物酶体增殖物激活受体γ(PPARγ)、胆固醇调节元件结合蛋白1(SREBP1)和硬脂酰辅酶A去饱和酶(SCD)的mRNA相对表达量均显著升高(P<0.05)。6)与对照组1相比,保护组细胞内乳脂合成相关蛋白ACSS2、FABP3、PPARγ和SCD的相对表达量均显著上升(P<0.05)。综上所述,BLF不仅能通过提升Nrf2及其下游抗氧化基因的表达,从而提升氧化损伤的BMECs的抗氧化能力,降低氧化应激带来的氧化损伤,而且BLF还能够有效提升乳脂相关基因和蛋白的表达,从而促进乳脂合成,有效减少氧化损伤对机体乳脂合成的影响。

Efficacy of fermented milk and whey proteins in Helicobacter pylori eradication:A review

Helicobacter pylori (H. pylori) eradication is considered a necessary step in the management of peptic ulcer disease, chronic gastritis, gastric adenocarcinoma and mucosa associated lymphoid tissue lymphoma. Standard triple therapy eradication regimens are inconvenient and achieve unpredictable and often poor results. Eradication rates are decreasing over time with increase in antibiotic resistance. Fermented milk and several of its component whey proteins have emerged as candidates for complementary therapy. In this context the current review seeks to summarize the current evidence available on their role in H. pylori eradication. Pertinent narrative/systematic reviews, clinical trials and laboratory studies on individual components including fermented milk, yogurt, whey proteins, lactoferrin, &#x003b1;-lactalbumin (&#x003b1;-LA), glycomacropeptide and immunoglobulin were comprehensively searched and retrieved from Medline, Embase, Scopus, Cochrane Controlled Trials Register and abstracts/proceedings of conferences up to May 2013. A preponderance of the evidence available on fermented milk-based probiotic preparations and bovine lactoferrin suggests a beneficial effect in Helicobacter eradication. Evidence for &#x003b1;-LA and immunoglobulins is promising while that for glycomacropeptide is preliminary and requires substantiation. The magnitude of the potential benefit documented so far is small and the precise clinical settings are ill defined. This restricts the potential use of this group as a complementary therapy in a nutraceutical setting hinging on better patient acceptability/compliance. Further work is necessary to identify the optimal substrate, fermentation process, dose and the ideal clinical setting (prevention/treatment, first line therapy/recurrence, symptomatic/asymptomatic, gastritis/ulcer diseases etc.). The potential of this group in high antibiotic resistance or treatment failure settings presents interesting possibilities and deserves further exploration.

Correlation between the Insertion/Deletion Mutations of Prion Protein Gene and BSE Susceptibility and Milk Performance in Dairy Cows

Objective To investigate the 23 bp and 12 bp insertion/deletion(indel)mutations within the bovine prion protein(PRNP)gene in Chinese dairy cows,and to detect the associations of two indel mutations with BSE susceptibility and milk performance.Methods Based on bovine PRNP gene sequence,two pairs of primers for testing the 23 bp and 12 bp indel mutations were designed.The PCR amplification and agarose electrophoresis were carried out to distinguish the different genotypes within the mutations.Moreover,based on previous data from other cattle breeds and present genotypic and allelic frequencies of two indels mutations in this study,the corrections between the two indel mutations and BSE susceptibility were tested,as well as the relationships between the mutations and milk performance traits were analyzed in this study based on the statistical analyses.Results In the analyzed Chinese Holstein population,the frequencies of two"del"alleles in 23 bp and 12 bp indel muations were more frequent.The frequency of haplotype of 23del-12del was higher than those of 23del-12ins and 23ins-12del.From the estimated r2and D’values,two indel polymorphisms were linked strongly in the Holstein population(D’=57.5%,r2=0.257).Compared with the BSE-affected cattle populations from the reported data,the significant differences of genotypic and allelic frequencies were found among present Holstein and some BSE-affected populations(P<0.05 or P<0.01).Similarly,there were significant frequency distribution differences of genotypes and alleles among Chinese Holstein and several previous reported healthy dairy cattle(P<0.05 or P<0.01).Moreover,association of genotype and combined genotypes of two indel polymorphisms with milk performance and resistant mastitis traits were analyzed in Holstein population,but no significant differences were found(P>0.05).Conclusions These observations revealed that the influence of two indel mutations within the bovine PRNP gene on BSE depended on the breed and they did not affect the milk production traits,which layed the foundation for future selection of resistant animals,and for improving health conditions for dairy breeding against BSE in China.

姜黄牛初乳发酵乳的制备及其抗氧化活性研究

为开发一种具有较高抗氧化能力的姜黄牛初乳发酵乳,以感官评价为响应值,在单因素的基础上,通过响应面分析法对姜黄牛初乳发酵乳配方进行优化,并对产品的理化指标和抗氧化活性进行分析。结果表明,姜黄牛初乳发酵乳的最佳工艺为:姜黄素微胶囊添加量0.5%、接种量2%、牛初乳添加量30%、蔗糖添加量6%,此时发酵乳感官评分达到91.24;姜黄牛初乳发酵乳的硬度为0.97 N,弹性3.96 mm,胶粘性0.83 N,内聚性0.83,黏度0.62 mJ,酸度为88.63°T,蛋白质含量3.98 g/100 g,脂肪含量0.46 g/100 g,乳酸菌数6.59×10^(8)CFU/mL,未检出致病菌;在酸奶浓度为25%时,姜黄牛初乳发酵乳对DPPH·、ABTS^(+)·和羟自由基的清除率分别为89.59%、95.39%、63.26%,抗氧化能力明显优于普通发酵乳。