重组脂联素(rAdp)对皖南花猪骨骼肌卫星细胞脂联素及受体和肌球蛋白重链基因表达的影响

脂联素(Adp)是主要由脂肪组织分泌的细胞因子,其作用受到普遍关注.选择10 d皖南花猪半腱肌分离骨骼肌卫星细胞,用不同浓度(0、1、5和10μg/mL)的重组脂联素(rAdp)分别处理12和24 h,采用荧光定量PCR检测骨骼肌细胞中脂联素(Adp)、脂联素受体1(AdpR1)、脂联素受体2(AdpR2)和肌球蛋白重链(MyHC),4种亚型MyHC1、MyHC2a、MyHC2b、MyHC2x,以及AMP激活蛋白激酶(A MPK)、过氧化物增殖剂活化受体α(PPARa)的基因表达.结果显示:(1)1μg/mL rAdp处理后,Adp和A dpR1基因表达量极显著增加,AdpR2的表达量在处理24 h极显著增加.而5和10 μg/ml组Adp、AdpR1和AdpR2的表达量低于对照组;(2)1μg/mL rAdp处理显著上调MyHC1和MyHC2x的基因表达量,而MyHC2b的表达量则在处理24 h极显著下降.5和10μg/mL rAdp处理显著下调MyHC2b的基因表达量,而对MyHC1无显著影响.10μg/mL处理后MyHC2a的表达量极显著下降,5μg/mL处理后MyHC2x的表达量极显著增加;(3)1、5和10 μg/mL rAdp处理12 h后,AMPK基因表达量极显著高于对照组,但是低剂量组具有较高的基因表达量.1μg/mL rAdp处理12和24 h,PPARa基因表达量极显著高于对照组,然而高剂量组没有这种效应.结果提示,Adp作用于骨骼肌,可能是与受体结合后通过AMPK和PPARa两个信号途径,提高MyHC1、MyH2x和降低MyH2b基因表达量,改变肌纤维组成.     

PGC-1α基因在两个品种鸡两种表型肌肉中的差异表达

过氧化物酶体增殖物激活受体γ辅激活因子1 (peroxisome proliferator-activated receptor-γ coactivator-1 alpha,PGC-1α)是调控肌纤维类型转换的关键因子,已成为研究畜禽肌肉品质的一个热点基因.为探讨生长速度不同的两个品种鸡(Gallus gallus)生长发育早期两种表型肌肉中PGC-1α的表达情况,本研究利用qRT-PCR和Western blot分别检测PGC-1α mRNA和蛋白在慢生型清远麻鸡和速生型隐性白羽鸡的比目鱼肌(主要含慢肌纤维)和趾长伸肌(主要含快肌纤维)中的发育性(0,1,3,5,7和9周龄)表达变化.结果显示,同一种肌肉组织中PGC-1α mRNA均是0周龄时表达水平最高,显著高于其他各周龄(P＜0.05);肌肉组织中PGC-1α mRNA和蛋白表达趋势虽然均不相同,但其表达均与肌肉表型和品种相关,即相同周龄时,两个品种鸡的比目鱼肌中PGC-1α mRNA和蛋白表达均高于其趾长伸肌,两种表型肌肉中PGC-1α mRNA和蛋白表达均是清远麻鸡高于隐性白羽鸡,且在0周龄时,mRNA表达差异均极显著(P＜0.01).结果提示,鸡骨骼肌PGC-1α表达可能与慢肌纤维含量密切相关,并与鸡肉品质存在关联.研究结果有助于了解PGC-1α在鸡骨骼肌中的作用,并为改良鸡肉品质提供理论依据.     

钙调磷酸酶催化亚基A基因(PPP3CA)在不同品种鸭发育早期肌肉中的表达及其与肌纤维特性的相关性

钙调磷酸酶催化亚基A(protein phosphatase 3 catalytic A,PPP3CA)是PPP3C在骨骼肌中的主要亚型,在肌纤维分化中起重要作用.为研究PPP3CA基因在不同品种鸭(Anas platyrhynchos domestica)发育早期肌肉中的表达规律及其与肌纤维特性的相关性,本研究选用生长速度差异较大的金定鸭和高邮鸭,采用实时荧光定量PCR检测鸭13、17、21、25和27胚龄及7日龄胸肌和腿肌中PPP3CA mRNA的表达水平.结果表明,两鸭种同一肌肉组织中PPP3CA mRNA的表达表现出显著的时间特异性,而品种和性别效应并不显著.两鸭品种胸肌和腿肌中PPP3CA mRNA的表达模式虽不同,但均是在13胚龄(13embryonic day,E13 d)时最高,且在出雏后7日龄时极显著高于27胚龄(出雏前)(P＜0.01).胸肌中PPP3CA mRNA在21胚龄时显著低于其他各胚龄或日龄(P＜0.01);腿肌中PPP3CA mRNA在21胚龄时表达量较高,27胚龄时降到最低,且极显著低于其他各胚龄或日龄(P＜0.01).相关性分析结果显示,两鸭品种腿肌PPP3CA mRNA表达量与本研究前期检测的肌纤维类型、直径、面积和密度等肌纤维特性呈现不同程度的线性相关;两鸭品种胸肌和腿肌PPP3CA mRNA表达量与均与本研究前期检测的类胰岛素生长因子(insulin-like grow factor-Ⅰ,IGF-Ⅰ)mRNA表达量呈显著的正相关(P＜0.05或P＜0.01).初步推测鸭发育早期骨骼肌中PPP3与肌纤维类型和肌纤维生长发育密切相关,与IGF-Ⅰ可能共同参与了对骨骼肌生长发育的调节.本研究结果将有助于了解PPP3在鸭肌肉早期发育中的作用,并为改良鸭肉品质提供理论依据.     

灯盏花乙素(Scu)对猪肾小管上皮细胞(LLC-PK1)细胞热休克蛋白72(HSP72)及凋亡相关基因表达的影响

灯盏花乙素(scutellarin,Scu)具有清热解毒、扩张心脑血管、改善微循环等作用。通过观察不同浓度Scu对猪肾小管上皮细胞(pig kidney proximal tubular,LLC-PK1)热休克蛋白72(heat shock protein72,HSP72)、B细胞淋巴瘤/白血病-2(B-cellymphoma/leukemia-2,Bcl-2)及Bcl-2相关X蛋白(Bcl-2associated X protein,Bax)表达的影响,探讨灯盏花乙素提高细胞耐热性的可能机制。将培养的LLC-PK1细胞随机分为37℃空白对照(Ⅰ组),42℃单纯热应激1 h(Ⅱ组),以及分别用不同浓度(1×10-5、1×10-6和1×10-7mol/L)Scu处理并42℃热应激1 h组(分别为Ⅲ、Ⅳ和Ⅴ组),提取各组细胞总RNA和总蛋白,用实时荧光定量PCR和Western blot分别检测HSP72、Bcl-2和Bax基因及蛋白的表达量。结果显示,与Ⅰ组相比,Ⅱ组LLC-PK1细胞HSP72和Bax的mRNA及蛋白表达量显著升高(P0.05),Bcl-2/Bax mRNA和蛋白比值显著降低(P0.05),Bcl-2 mRNA和蛋白表达量并无显著差异(P0.05)。与Ⅱ组相比,Ⅳ和Ⅴ组LLCPK1细胞HSP72 mRNA和蛋白的表达量均显著升高(P0.05),Ⅲ组无显著差异(P0.05);Ⅳ组细胞Bcl-2 mRNA和蛋白表达量均显著升高(P0.05),Ⅲ和Ⅳ组并无显著差异(P0.05);Ⅲ、Ⅳ和Ⅴ组Bax mRNA和蛋白表达量均显著降低(P0.05);Ⅳ和Ⅴ组Bcl-2/Bax蛋白比值显著升高(P0.05)。研究结果表明,热应激条件下Scu可诱导LLC-PK1细胞HSP72表达,提高Bcl-2/Bax比值。结果提示,Scu可增强细胞的抗热休克作用。本研究丰富了体外培养细胞热应激反应的理论,为在实践中增加细胞抗热休克能力提供了理论依据。     

山羊妊娠期日粮添加酵母硒对后代羔羊睾丸GPxs表达的影响

为探明妊娠母山羊日粮中酵母硒水平对其所产后代公羔睾丸GPxs活性、睾丸组织GPx1,GPx3和GPx4 mRNA表达及其GPx4蛋白表达的影响,采用实时定量PCR进行睾丸GPxs mRNA定量分析,并采用免疫荧光技术对GPx4蛋白定量分析.结果显示妊娠母山羊日粮中添加1.0 mg· kg-1硒组(Ⅱ组)可极显著提高后代公羔睾丸GPxs的活性(P＜0.01).与对照组相比,Ⅱ组GPx1 mRNA表达量提高了0.84倍,GPx3 mRNA表达量提高了2.6倍,GPx4 mRNA表达量提高5倍,GPx4蛋白表达量显著增加(P＜0.01),但4.0 mg·kg-1硒组后代睾丸GPx4蛋白有过表达现象.妊娠母羊日粮添加1.0 mg· kg-1酵母硒(日粮硒含量1.045 mg· kg-)可明显提高后代公羔睾丸中GPxs基因的表达.本研究不仅丰富了硒营养调控理论,而且对肉羊生产具有指导意义.     

植物乳杆菌对苏尼特羊肠道菌群、血浆代谢物及肉品质的影响

为了研究植物乳杆菌对苏尼特羊肠道菌群、血浆代谢物和肉品质的影响及其作用机理,选取三月龄苏尼特羊为试验对象,随机分为2组:对照组(C组,基础日粮)和植物乳杆菌组(R组,基础日粮、活菌数为3×1010cfu/g植物乳杆菌),进行为期90 d的饲喂试验.屠宰后取其肠道内容物及背最长肌,利用高通量测序技术、代谢组学液相-色谱联...     

品种对羊肉乳化香肠品质的影响

从我国肉羊主产区采集到20个品种的羊肉样品,按照相同工艺制作成乳化香肠,比较了不同品种羊肉乳化香肠的颜色、凝胶性、乳化稳定性、保水性等品质,并对结果进行聚类分析。结果显示:a*值、硬度、粘聚性、咀嚼性、乳化稳定性、保水性及蒸煮损失在品种间变异系数大,所有指标在P0.01水平均存在极显著差异;苏尼特羊、巴尔楚克羊、吐鲁番黑羊、敖汉细毛羊肉制作的乳化香肠品质显著优于新疆细毛羊、阿勒泰羊、乌珠穆沁羊×小尾寒羊、萨福克×小尾寒羊肉制作的乳化香肠;聚类分析表明,不同饲养方式肉羊的羊肉制成的乳化香肠品质差异明显,放牧方式肉羊的羊肉制成的乳化香肠总体品质优于舍饲。     

猪腺苷酸活化蛋白激酶α基因(AMPKα)特异性siRNA载体的构建及干扰效果评价

腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK),在真核细胞生物中广泛存在,是调控机体能量代谢的关键酶.本研究旨在构建并筛选猪(Sus scrofa)AMPKα基因的有效siRNA干扰载体,并探讨AMPKα基因对脂肪分解关键酶基因表达的影响.根据猪AMPKα基因(GenBank登录号:NM-001167633)全长cDNA序列,设计合成其特异性发夹siR-NA干扰片段,将其克隆插入pSilencer 4.1-CMV neo Vector干扰载体中,构建猪AMPKα基因的siRNA真核表达载体RA1和RA2,并通过PCR、双酶切和测序对其进行鉴定.构建成功后转染猪肌内脂肪前体细胞并检测其干扰效果及对脂肪分解关键酶一一激素敏感脂肪酶(hormone sensitive lipase,HSL)、脂肪甘油三酯脂肪酶(adipose triglyceride lipase,ATGL)和肉毒碱棕榈酰转移酶(carnitine palmitoyl transferase,CPTl)基因表达的影响.结果表明,所构建的猪AMPKα基因的特异性siRNA表达载体RA1和RA2均可降低猪AMPKα mRNA表达(P＜0.05),而且RA2干扰效果优于RA1.用RA2干扰AMPKα后,猪肌内脂肪前体细胞中AMPKα及脂肪分解关键酶HSL、ATGL和CPT1基因表达量显著下降(P＜0.05).提示,抑制AMPKα基因表达后,猪肌内脂肪前体细胞中脂肪分解和脂肪酸氧化速率降低.本研究结果为深入探讨AMPKα对猪脂肪代谢的影响机制及通过营养调控基因表达进而调控猪体脂沉积提供基础资料.     

α-硫辛酸对滩羊肌纤维类型和肉品质的影响及其调控机理

为研究α-硫辛酸对滩羊股二头肌肌纤维特性和肉品质的影响及其调控机理,该试验选取初始质量为(20.64±1.15)kg的4月龄健康滩羊12只,随机分为对照组(基础日粮)和α-硫辛酸组(基础日粮中添加600 mg/kgα-硫辛酸),饲喂试验预试期7 d,饲喂期60 d.以股二头肌为试验材料,分别测定肉品质、肌纤维特性、能量...     

红外辐射制备柠檬酸糯米淀粉酯工艺优化及功能特性

为提高柠檬酸淀粉酯制备效率,拓展淀粉在工业领域的应用价值,以糯米淀粉为研究对象、柠檬酸为酯化剂,红外辐射为核心制备技术,取代度为衡量指标,用单因素和响应面法优化柠檬酸淀粉酯的制备工艺条件,并对改性前后淀粉的理化性质、微观结构测定分析。最佳工艺参数为:红外辐射照度2 474 W/m2、红外辐射时间7.1 min、pH值为2.96、柠檬酸与淀粉质量比0.50。在优化条件下,取代度的验证试验结果为0.156,与响应面拟合模型预测值(0.158)吻合良好,红外辐射处理7.1min可达传统干热制备法5h的制备取代水平且两者理化性质和分子结构不存在显著差异性(P0.05),两者抗性淀粉含量分别提高50.15%和50.35%,表现较强的热稳定性、抗剪切和抗消化特性;傅立叶红外光谱图显示在1 749 cm~(-1)位置出现酯类C=O伸缩振动特征吸收峰,证实酯化反应的发生。表明应用红外辐射技术辅助高效制备良好性能的柠檬酸淀粉酯是有效的。     

Physicochemical Properties and In Vitro Starch Digestibility of Cooked Rice from Commercially Available Cultivars in Canada

The influence of amylose content, cooking, and storage on starch structure, thermal behaviors, pasting properties, and rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) in different commercial rice cultivars was investigated. Long grain rice with high‐amylose content had a higher gelatinization temperature and a lower gelatinization enthalpy than the other rice cultivars with intermediate amylose content (Arborio and Calrose) and waxy type (glutinous). The intensity ratio of 1047/1022 cm^–1 determined by Fourier Transform Infrared (FT‐IR), which indicated the ordered structure in starch granules, was the highest in glutinous and the lowest in long grain. Results from Rapid ViscoAnalyser (RVA) showed that the rice cultivar with higher amylose content had lower peak viscosity and breakdown, but higher pasting temperature, setback, and final viscosity. The RDS content was 28.1, 38.6, 41.5, and 57.5% in long grain, Arborio, Calrose, and glutinous rice, respectively, which was inversely related to amylose content. However, the SDS and RS contents were positively correlated with amylose content. During storage of cooked rice, long grain showed a continuous increase in pasting viscosity, while glutinous exhibited the sharp cold‐water swelling peak. The retrogradation rate was greater in rice cultivars with high amylose content. The ratio of 1047/1022 cm^–1 was substantially decreased by cooking and then increased during storage of cooked rice due to the crystalline structure, newly formed by retrogradation. Storage of cooked rice decreased RDS content and increased SDS content in all rice cultivars. However, no increase in RS content during storage was observed. The enthalpy for retrogradation and the intensity ratio 1047/1022 cm^–1 during storage were correlated negatively with RDS and positively with SDS (P ≤ 0.01).     

Structure,Physicochemical Properties,and In Vitro Starch Digestibility of Yellow Pea Flour Modified with Different Organic Acids

The objective of this study was to produce a pea flour ingredient with higher slowly digestible (SDS) and resistant (RS) starch fractions for functional food applications. Heat‐moisture treated flour (HMTF) in the presence of citric, gallic, or vanillic acids and esterified flour (EF) with citric acid were prepared and analyzed for structure and functionality using in vitro starch digestibility, differential scanning calorimetry, Rapid Visco Analyzer, swelling factor (SF), amylose leaching (AML), optical microscopy, and Fourier transform infrared (FT‐IR) spectroscopy. Significant (P < 0.05) increases in SDS and RS content of HMTF and EF were observed. Whereas the granule integrity and the birefringence were not affected by modification, the degree of crystalline order, which was determined by FT‐IR 1,047/1,022 cm⁻¹ peak ratio, was decreased. Gelatinization enthalpies of modified flour were lower than that of native flour, whereas the gelatinization endotherms of HMTF were shifted to higher temperatures and those of EF to lower temperatures. Pasting properties were also affected greatly by both treatments. HMTF demonstrated reduced SF and AML, whereas EF had reduced SF and increased AML. Further, the extent of changes in the structure and functionality of HMTF depended on the type of acid utilized. Overall, heat‐moisture treatment with an organic acid and esterification were effective modifications to produce a pea flour ingredient with enhanced SDS and RS content.     

石灰性土壤磷素的化学活化途径探讨

用草酸、草酸钠、柠檬酸和柠檬酸钠作为活化剂，加人不同含磷水平土壤中，通过室内培养试验和分析，结果表明：(1)0．1M草酸和0．1M柠檬酸都有一定的活化土壤磷素的作用，草酸作用最为显著。而相同浓度的草酸钠和柠檬酸钠未显示对土壤磷素的活化效果。(2)对土壤磷素的活化作用，草酸随其浓度的增加而增强，而柠檬酸活化土壤磷的能力有限。(3)柠檬酸在加人的6h之内，对活化土壤速效磷作用明显；而草酸在加人的48h之内，对活化土壤速效磷有十分显著的作用。无论是柠檬酸还是草酸，在其对土壤速效磷发挥活化作用期间，均随加人时间的延长而减弱。     

甘草根瘤菌CCNWGX035的抗逆特性及结瘤特征研究

Thirty-nine rhizobial isolates were isolated from the root nodules of Glycyrrhiza uralensis and Glyeyrrhiza glabra, growing in the arid and semiarid regions of northwestern China, to test their taxonomic position and stress tolerance and to select one promising putative inoeulant strain for further studies. On the basis of 113 physiological and biochemical characteristics, the isolates were clustered into three groups. One isolate CCNWGX035 was found to have high tolerance to NaC1, pH, and temperature. By sequencing the 16S rDNA, isolate CCNWGX035 was placed in genus Mesorhizobium. Nodulation tests demonstrated that the isolate not only formed nitrogen-fixing nodules on its original host plant Glyeyrrhiza glabra, but also on Sophora vieiifolia, Lotus cornieulatus, Trifolium repens, Melilotus suaveolens, and Sophora alopecuroides. On the basis of sequence analysis of the nodA gene, isolate CCNWGX035 was closely related to strains of the genus Mesorhizobium, exhibiting some novel characteristics of root nodule bacteria.     

Effects of citric acid on the viscoelasticity of cornstarch pastes

The effects of citric acid on the rheological properties of cornstarch pastes were studied by steady shear and dynamic oscillatory viscoelasticity, intrinsic viscosity measurements and microscopic observation. The pH of cornstarch dispersion was adjusted between 6.0 and 3.0. The viscosity of the pastes was increased by lowering the pH (between 5.5 and 3.6), while the viscosity of samples with pH below 3.5 decreased further than that of the control (pH = 6.3). Citric acid promoted the collapse of starch granules; however, adding excessive citric acid led to the hydrolysis of glucose chains. No decrease in the viscoelasticity was observed for cornstarch pastes by adding acid at 25 degrees C after gelatinization.     

Effect of Infrared and Conventional Drying Methods on Physicochemical Characteristics of Stored White Rice

The objective of this study was to investigate the effect of infrared (IR) drying followed by tempering and natural cooling on the change of physicochemical characteristics of white rice during up to 10 months of storage. The physicochemical characteristics of IR‐dried rice were also compared with those of conventionally dried rice. It took only 58 s to heat the rough rice from room temperature to 60°C with IR, and 2.17 percentage points of moisture was removed. After four months of storage, the increases in yellowness index, water uptake ratio, and volume expansion ratio of the rice dried with IR were 73.8, 63.9, and 55.3% those of rice dried with an ambient air drying method, respectively. IR drying slightly decreased the gelatinization temperature, enthalpy, and viscosities, reduced the changes in microstructure, and maintained cooking characteristics during storage. Therefore, the IR drying process is recommended to maintain the quality of white rice during storage.     

不同抗氧化剂预处理防止优质籼稻种胚愈伤组织褐化的研究

以优质籼稻桂华占和油占8号的成熟胚为外植体，采用0．1％的3种抗氧化剂对离体稻胚作不同时间预处理，研究抗氧化剂对2个籼稻品种种胚愈伤组织的诱导和防褐效应。结果表明，柠檬酸的适宜处理时间为18h和24h，抗坏血酸(VC)和聚乙烯吡咯烷酮(PVP)的适宜处理时间均为3h；柠檬酸的防褐效果最好，但会降低愈伤组织的诱导率；抗坏血酸的防褐效果次之，且能提高愈伤组织的诱导率并促进愈伤组织生长；PVP仅在愈伤组织诱导阶段有一定的防褐作用。     

Morphological diversity of panicle traits in Kam fragrant glutinous rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>)

Panicle traits are the most intuitive and representative features of rice germplasm resources that have been utilized in the determination of its identity, genetic diversity, yield, and quality. Based on the approaches of ethnobotany, cultural anthropology and plant morphology, we analyzed the panicle traits of 95 traditional Kam fragrant glutinous rice landraces according to folk classification in Qiandongnan Prefecture of Guizhou Province in the past 10 years. A total of 95 Kam fragrant glutinous rice landraces were tested, of which 91% consisted of those with awns, and landraces with awn lengths of 2–6 cm comprised 62%. The coefficient of variation (CV) of awn color, husk color and Grain color was more than 50%, thereby indicating extensive morphological variations among the traditional Kam fragrant glutinous rice landraces. The average Shannon–Wiener value (diversity index, H′) for panicle qualitative traits was 0.50, which was significantly higher than that of quantitative traits (0.22), thereby indicating a relatively higher degree of genetic diversity among qualitative traits. Cluster analysis of panicle morphological traits showed that 95 Kam fragrant glutinous rice landraces could be divided into five categories, using the Euclidean distance of 0.68 as threshold. Each cultivar manifested unique panicle traits. The present study on the morphological diversity of Kam fragrant glutinous rice landraces provided basic information that may be utilized for the conservation and sustainable use of Kam fragrant glutinous rice landraces.     

稻米淀粉糊老化动力学研究

以不同类型稻米为原料，用旋转粘度仪研究较稀浓度淀粉糊的老化动力学，以预测和控制稻米淀粉糊老化。结果表明：稻米淀粉糊呈假塑性流体的特征，随存放时间的延长，其流变指数上升，淀粉糊的刚性增大。用流变指数和一级化学反应动力学模型能较好的描述淀粉糊的老化特性。淀粉糊的老化与其分散相的凝聚、沉淀和连续相的特性有关。淀粉糊中直链淀粉和支链淀粉的相互作用会使其老化进一步加深。