Cellulase in the Host–parasite System Phaseolus vulgaris (L.)–Uromyces appendiculatus [Pers.] Link

Activity of cellulase and xylanase in the intercellular washing fluid (IWF) of bean plants (Phaseolus vulgaris, cultivar Fori) was monitored during infection with bean rust (Uromyces appendiculatus). In infected plants, cellulase activity could be detected at 2 days after inoculation and reached its maximum between 7 and 8 days after inoculation. The enzyme activity was not detected in healthy controls. The cellulase had a pH optimum at pH 5.5 and a temperature optimum at 30°C. Complete inactivation of cellulase occurred after heating to 50°C for 30min. In non-denaturing polyacrylamide gradient gels, the enzyme exhibited four bands (molecular masses approximately 70, 95, 120, 170kDa). After isoelectric focusing, eight cellulase isoforms with pI values pI 4.6–4.8; 5–5.1; 5.4; 5.5; 5.9; 6; 6.5; 7 appeared. Two dimensional electrophoresis yielded 13 cellulase isoforms. Unlike cellulase, low levels of xylanase were detected in healthy controls. The activity of this hydrolase did not increase due to rust infection.     

A single amino acid substitution in puroindoline b impacts its self-assembly and the formation of heteromeric assemblies with puroindoline a

Puroindolines (PINs) A and B were purified from soft (Paledor) and hard (Recital, Courtot) wheat cultivars. Their purity and heterogeneity due to post-translational processing were characterized by SDS- and acid-PAGE, reversed-phase HPLC and mass spectrometry. By using dynamic light scattering (DLS), asymmetrical flow field-flow fractionation (AF4) and size exclusion chromatography (SEC), we showed that the size distributions of PINA are similar for the three varieties and that, in solution, they self-assembled into small aggregates, mainly dimers. Conversely, PINB isolated from hard varieties (PINB-D1b and PINB-D1d) are assembled into large aggregates while PINB-D1a formed small aggregates, mainly monomers. Mixed solutions of PINA and PINB formed heteromeric aggregates. The large PINB-D1b aggregates were retained even at a high (4:1) PINA/PINB weight ratio. Reversible dissociation of large aggregates into small aggregates suggested that weak interactions control the self-assembly of PINs. The aggregative properties of PINs have now to be taken into account when studying their interactions with other components to decipher the causal relationships between these proteins and grain hardness.     

Oat protein solubility and emulsion properties improved by enzymatic deamidation

Oat protein produced by a dry milling process was enzymatically deamidated by a food-grade protein-glutaminase (PG), and the effects on structure, solubility and emulsifying properties of oat proteins were studied. The reactions were conducted at neutral pH and low salt concentration conditions. Oat proteins were deamidated up to a deamidation degree of 59%. The solubility of proteins doubled. Oil-in-water emulsions prepared with the native and deamidated oat proteins differed as the emulsions prepared from oat proteins with high deamidation degree had a more uniform oil droplet particle size and longer stability. Fourier transform infrared (FT-IR) analysis demonstrated that oat protein secondary structure became more flexible by deamidation. Protein-glutaminase mediated deamidation appeared to be a promising technique to improve oat protein functionality such as emulsifying ability and solubility.     

秦岭坡旱地不同桔梗栽培品种亲缘关系鉴别

为对秦岭坡旱地中药材桔梗品种选育及种质资源鉴定提供依据,应用聚丙烯酰胺凝胶电泳(PA GE)技术研究了不同产地三年生桔梗不同叶位酯酶同工酶(EST)的表达差异,并通过EST-PAGE 图谱迁移率（Rf）、联合系数（S）、酶谱相似度（T）综合分析方法,初步评价了 目前在商洛坡旱地栽培的不同产地桔梗品种的亲缘关系。结果表明：6种不同产地桔梗间的 亲缘关系大小顺序为：甘肃平凉＞山东淄博＞四川广元＞西安蓝田＞内蒙赤峰≈陕西商洛, 内蒙赤峰与陕西商洛桔梗疑为同一品种。     

PAM与天然土壤改良材料混合对部分土壤理化性质的影响

为了充分发挥高分子土壤改良剂和一些天然土壤改良材料改土培肥作用,选取了高分子土壤改良剂聚丙烯酰胺（PAM）,分别与具有改土培肥功能的天然土壤改良材料——油渣、秸秆、蛭石、草炭、页岩、风化煤按不同用量混合施入土壤,利用湿筛法、称重法、重铬酸钾容量法、离心机法,测定对土壤水稳性团聚体、孔隙度、土壤有机质、有效含水量和水分蒸发等土壤理化性质的影响。结果表明:（1）各处理与单施PAM相比,对土壤孔隙度没有明显影响,但对土壤水稳性团聚体含量均有不同程度的提高,其中PAM与0.6%秸秆处理和PAM与0.3%油渣处理对其影响最为显著,较单施PAM提高4.9%和4.6%;（2）通过天然土壤改良剂自身的有机质含量测定以及PAM分别与六种天然土壤改良材料混合施入土壤培养前后有机质含量测定,结果分析得出,随着材料施入量增加,各处理培养前后土壤有机质含量呈现递增趋势;风化煤处理对土壤有机质含量增加显著,培养后其土壤损失有机质百分比较高,幅度约50%,页岩处理培养土壤损失有机质的百分比较少,幅度约为6%;（3）通过各处理在不同水吸力下土壤持水量和蒸发观测得出,PAM与3%的风化煤处理显著提高土壤有效水含量,PAM与1%的秸秆处理和PAM与1%的油渣处理显著提高了土壤抗蒸发能力。总体上,PAM与风化煤、PAM与油渣和PAM与秸秆处理对土壤结构、土壤有机质含量、土壤水分等方面有显著改善作用。这对进一步研制具有多重功能的土壤改良剂提供参考。     

不同检测方法对甜菜ISSR引物多态性的影响

为了探讨不同检测方法对甜菜ISSR引物扩增效果的影响以及各方法的优缺点,笔者应用非变性聚丙烯酰胺凝胶电泳和琼脂糖凝胶电泳两种检测方法对甜菜ISSR 引物扩增效果进行了检测。利用12个不同的甜菜品种,对10 个ISSR引物进行扩增,分别采用6%的非变性聚丙烯酰胺凝胶电泳、1%的琼脂糖凝胶电泳以及2%的琼脂糖凝胶电泳对ISSR-PCR的扩增产物进行分离。结果表明：6%的聚丙烯酰胺凝胶电泳无论是检测的总条带数还是多态性条带数均远高于琼脂糖凝胶电泳,且条带清晰,易于识别,而2%的琼脂糖凝胶电泳检测的条带数高于或等于1%的琼脂糖凝胶电泳,且条带更易于识别,因此,对于利用ISSR 引物进行QTL定位、指纹图谱构建以及遗传多样性分析时,推荐使用6%的非变性聚丙烯酰胺凝胶电泳,而对于种子纯度鉴定以及需要对ISSR扩增产物进行测序,则推荐使用2%的琼脂糖凝胶电泳。     

甘蓝型油菜叶片蛋白质双向电泳体系优化

比较了甘蓝型油菜叶片总蛋白质提取的2种不同方法,探讨了叶片蛋白质分离的双向凝胶电泳技术优化方案.结果表明:采用TCA/丙酮法较Tris-Cl法更适合蛋白质提取,选择pH为4～7的固相胶条和分离胶浓度为12％的聚丙烯酰胺凝胶(SDS-PAGE)能够使蛋白质得到充分分离,采用考马斯亮蓝G250染色剂进行2次染色,可提高2-DE分辨率和实验解析度,优化后的双向电泳体系能够分离出2000个以上的蛋白点,并且重复稳定性好.