不同种污泥胞外聚合物的提取方法与组成特征

针对废水生物处理系统中各类污泥的功能与结构特点,比较了常用胞外聚合物(EPS)提取方法的效能优劣,并从反应器溶解氧条件、微生物营养类型和污泥空间形态等方面对不同种污泥的EPS组成特征进行了分析,重点强调了EPS组分在培养全自养脱氮颗粒污泥等特殊微生物聚集体中的重要作用。     

人居和荒漠草原生态条件下小花棘豆叶片蛋白质表达谱分析

利用双向电泳技术,对比两种生境下(A地为公园,B地为荒漠草原)小花棘豆的蛋白质差异表达谱,选取其中的差异蛋白点进行MADLI-TOF-MS鉴定,获得的PMF数据经Mascot软件在NCBI NR数据库上检索分析后确认蛋白种类,结果表明:相对A地,B地小花棘豆光合作用相关调控酶类表达下调,而光合作用结构蛋白如叶绿素球蛋白表达上调;B地小花棘豆光合速率下降,可能是受光合调控酶表达下调的影响;B地ATP合成相关蛋白的表达上调,说明在干旱、高盐、氮磷含量偏低的环境下生长可能需要消耗更多能量.另外,B地小花棘豆中发现一些与胁迫相关蛋白出现上调或者特异性表达,这些蛋白的表达可能跟小花棘豆能够适应逆境有着密切的关系.     

日粮蛋白水平对单胃动物肠道消化吸收功能及健康影响的研究进展

动物肠道具有消化吸收和免疫防御的双重作用,肠道健康受肠道的营养物质吸收、黏膜免疫以及微生物等多方面影响。日粮蛋白水平过高或过低不仅影响肠道正常的发育,甚至会破坏肠黏膜、限制肠道吸收、引发病原菌的增殖,从而影响畜禽健康。本文综述了日粮中不同蛋白水平对单胃动物肠道发育、消化酶及激素分泌、肠道免疫等影响的研究进展,为今后优化日粮配方、节约蛋白原料、改善肠道健康提供理论依据。     

楸树花粉蛋白质提取方法研究

本研究以3种楸树的花粉为试材,采用不同的蛋白质提取方法,利用考马斯亮蓝染色法测定了3个树种花粉蛋白质的含量,并通过SDS-PAGE电泳对花粉蛋白质组分进行了分析。结果表明:采用TCA/丙酮沉淀法提取蛋白质,南京老山楸树花粉蛋白质提取率最高;采用不同pH值(6.8、8.8、9.5)的Tris-HCl提取液提取蛋白质,随着pH值不断增大,其蛋白质提取率显著提高,当pH值达9.5时,蛋白质含量最大,SDS-PAGE电泳结果也显示此时蛋白质带明显增加;采用不同pH值(6.8、8.8、9.5)的Tris-HCl提取液提取花粉蛋白质,发现花粉蛋白质分离纯化效果存在明显差异,究其原因可能是pH值不同的影响或浸提样品浓度的差异性造成的。     

Wheat (Triticum aestivum L.) grain proteome response to elevated [CO2] varies between genotypes

The impact of rising carbon dioxide concentration ([CO₂]) in the atmosphere on wheat grain protein concentration and proteome was investigated in this study. Wheat genotypes (H45, SB003, SB062 and Yitpi) were grown in the Australian Grains Free-Air CO₂ Enrichment (AGFACE) facility, Horsham, Victoria, Australia under ambient [CO₂] (a[CO₂], 391 μmol mol⁻¹) and elevated [CO₂] (e[CO₂], 550 ± 20 μmol mol⁻¹). Grain yield and grain protein concentration were measured. Global grain proteome comparison was carried out using stable isotope dimethyl labelling followed by liquid chromatography - mass spectrometry (LC-MS/MS). Grain yield was significantly increased at e[CO₂], whereas protein concentration was significantly decreased and responses varied between genotypes. Proteome-wide analysis revealed that protein composition was also altered under e[CO₂]. Grain protein concentration and composition of SB003 was very responsive to e[CO₂]. Mainly storage proteins were decreased at e[CO₂] and the responses varied between genotypes. These findings suggest that e[CO₂] may have a major impact on grain protein quality and thus bread quality and human and animal nutrition. Further, these findings suggest that [CO₂] insensitive cultivars can be identified for grain quality improvement under changing climate.     

Extractability and chromatographic separation of rye (Secale cereale L.) flour proteins

A size exclusion – high performance liquid chromatography (SE-HPLC) method originally developed for separating wheat, barley or rice proteins was applied to study the extractability and molecular weight (MW) distribution of rye flour proteins. These were extracted with 50 mmol/l sodium phosphate buffer (pH 6.8) containing 2.0% (w/v) sodium dodecyl sulfate (SDS) and, optionally, 1.0% (w/v) dithiothreitol (DTT). About 95% of the proteins were extracted in buffer containing 2.0% SDS. Addition of 1.0% DTT to such buffer increased the protein extractability to 100%, indicating that rye flour contains some proteins cross-linked by disulfide (SS) bonds. The SE-HPLC profiles revealed that rye flour contains SS-linked HMW-secalins and 75 k γ-secalins which elute in specific peaks. Upon reduction, these SS-linked protein aggregates dissociate and some entrapped albumins, globulins and/or ω-secalins are released. Rye flour albumins and globulins elute over the entire SE-HPLC profile. In contrast, the monomeric ω-secalins and 40 k γ-secalins are detected in specific well resolved SE-HPLC peaks. The applied fast and reproducible method can be used to characterise and quantify rye flour proteins and to determine changes as a result of processing.     

Nitrogen fertilisation effects on technological parameters and carotenoid,tocol and phenolic acid content of einkorn (Triticum monococcum L. subsp. monococcum): A two-year evaluation

Recent studies on einkorn wheat, an underutilised relative of durum and bread wheat, demonstrated its outstanding nutritional characteristics and fostered a renewed interest for its cultivation. Einkorn is a disease-resistant and thrifty crop, supplying flour with optimal composition even with minimal agronomic management. To understand the role of nitrogen fertilisation on its composition and nutritional quality, a two-year study comparing five different nitrogen treatments (0 kg/ha, 40 and 80 kg/ha at tillering, 40 and 80 kg/ha at heading) was performed on three einkorn accessions.The two years had similar temperatures but very different rainfall profiles, so the climate had a strong effect on most traits, including thousand kernels weight, Falling number, viscoamylographic parameters, carotenoid and phenolic acid concentration. On the other hand, nitrogen fertilisation improved protein content, SDS sedimentation volume and phenolic acids concentration. Carotenoids synthesis was slightly limited with increasing fertilisation; a similar, but less evident, effect was present for tocols. The results demonstrate that einkorn wheat does not require abundant nitrogen fertilisation to provide flour with good nutritional and technological characteristics.     

视黄醇结合蛋白4基因调控动物繁殖性能的研究进展

视黄醇结合蛋白4(RBP4)是孕体产生的主要蛋白质之一,也是动物体内唯一一种能够在血液中运载维生素A的转运蛋白,在协助视黄醇发挥生理作用中至关重要。文章介绍了RBP4基因在动物胚胎发育、产仔性能、睾丸功能和精液品质等方面的重要作用,并对RBP4基因多态性与动物繁殖性能的关系进行了阐述,以期为RBP4相关研究提供参考。     

GPV感染扰动雏鹅系统互作网络的研究

为了解GPV(Goose parvovirus)侵染的病理学致病机理,探究GPV感染扰动雏鹅动态代谢网络平衡系统,对GPV感染雏鹅血液中的蛋白质、代谢酶活性及其同工酶结构和功能等进行生化分析。结果显示,GPV感染雏鹅的血液中,蛋白酶、Est、POD、SOD、ALP、ADH、Amy、CAT、GPT、LDH活性分别提高约41%/63%,30%/53%,50%/14%,36%/73%,156%/142%,1005%/22%,36%/26%,13%/51%,60%/244%,289%/139%;Ig G、IgM含量分别降低约50%,40%;蛋白质含量增长约50%,GPV感染雏鹅的血浆Est、SOD、ADH、Amy同工酶分别新增2,2,1,3条酶谱带,Est同工酶消减2条慢区谱带;血细胞Est、POD、SOD、Amy同工酶分别新增1,2,1,2条酶谱带;血液中CAT、LDH、GPT、ALP同工酶分别出现7,1,3,3条酶带变异,血细胞CAT、ADH同工酶分别缺少快区和慢、快区酶带,ALP同工酶在血浆与血细胞方面分别缺少慢区和快区酶带。同时显示重链59 kDa蛋白带是CK组IgM/G的共同特征,感染组Ig G还缺失258,36 kDa蛋白带;血浆与血细胞分别新增加131,86,43,33 kDa和144,104,58,53 kDa蛋白。血浆消减1条慢区酶蛋白,血细胞增加2条慢区酶蛋白。提示GPV感染应激与寄主蛋白质、蛋白酶及同工酶基因表达的协同作用,通过独特的扰动宿主动态平衡代谢网络直接或间接调控细胞易感性能。     

Corn proteins solubility changes during extrusion and traditional nixtamalization for tortilla processing: A study using size exclusion chromatography

Changes in the solubility of corn proteins occurring during traditional nixtamalization and extrusion processes used to produce tortillas were studied using size exclusion chromatography, SDS-PAGE and the Dumas method to measure 50% propanol-insoluble protein. Size exclusion chromatography (HPL-SEC) studies furthered the understanding of protein solubility changes during both processes. Extrusion caused more protein aggregation in tortilla intermediate and final products than traditional nixtamalization. Mixing during extrusion and in the intermediate step of masa production in the traditional nixtamalization process was critical in reducing protein solubility. Baking tortillas also considerably reduced the protein solubility for the traditional nixtamalization process. Baking produced aggregation that could not be disrupted with a reducing agent.