大菱鲆致病性溶藻弧菌SR1的外膜蛋白及其抗原性分析

用十二烷基肌氨酸钠(Sarkosyl)抽提结合超速离心的方法提取了一株大菱鲆致病性溶藻弧菌(Vibrio alginolyticus)SR1和其他7株弧菌的外膜蛋白。通过SDS-PAGE图谱分析比较了这8株弧菌外膜蛋白的组成,结果表明,8株弧菌的外膜蛋白电泳一般可得到6-12条条带,其分子量多集中在65-106 kD和28-48 kD,其中36 kD的蛋白带为8株弧菌所共有。用兔抗SR1全菌血清进行Western-blot印迹显示,菌株SR1的外膜蛋白条带中有6条发生了阳性反应,其分子量分别为73 kD、48 kD4、5 kD3、9 kD、36 kD和32 kD。而其他7株弧菌的外膜蛋白与兔抗SR1血清也发生程度不等的阳性反应,这些阳性反应条带的分子量集中在65-73 kD、45-48 kD和36-41 kD之间,其中36 kD的外膜蛋白在8株弧菌中均出现明显的阳性反应,说明36 kD的外膜蛋白是这8株弧菌共有的特异性抗原。     

植物U-box蛋白研究进展

U-box结构是真核生物体内尤其是植物中广泛存在的一种高度保守的基序,其构象与RING-finger极其相似,两者都能发挥泛素连接酶E3的作用,促进底物蛋白泛素化降解。U-box基序还是泛素链聚集酶E4最主要的功能因子。在植物体内U-box经常与ARM重复耦联形成U-box/ARM结构,影响蛋白-蛋白互作,参与信号传导级联反应。许多植物U-box蛋白(PUB)能有效提高植株对干旱、高盐、异常温度等非生物胁迫的抵抗能力。此外,在植物对许多病原物的抗病反应中也需要U-box蛋白的参与。     

氮素用量对玉米子粒蛋白组分形成积累的影响

试验研究了不同施氮水平对春玉米子粒蛋白组分的影响。结果表明东农250、丰禾10子粒清蛋白含量呈下降趋势（东农250 NO处理灌浆初期略有升高）,四单19吐丝后7-21天略有增加而后下降;子粒球蛋白含量,东农250呈下降趋势（吐丝后7—21天略有升高）;四单19、丰禾10则先升高再降低而后略有升高再迅速降低;子粒醇溶蛋白含量呈高-低-高的变化趋势,不同品种间醇溶蛋白含量存在差异;子粒谷蛋白含量不断升高（东农250、四单19吐丝后21-28天略有降低）,不同品种春玉米谷蛋白含量存在差异。     

50年黑龙江省大豆遗传改良的产量及品质变化

本研究针对黑龙江省过去50年推广的大豆品种产量及品质变化进行研究。结果表明,品种推广年代与产量之间表现显著的线性回归关系,产量呈逐年增加的趋势,平均每年提高1．27％。产量的提高与英数、英粒数、粒数及收获指数密切相关,而与百粒重关系不大。经过50年的遗传改良,大豆蛋白质和脂肪含量变化不大,且品种间变异幅度较小。R2期（盛花期）叶氮含量、单株叶氮量、比叶氮及LAI（叶面积指数）与产量及品质关系不大,但此时期干物质重与产量里负相关关系,生育前期的干物质积累对产量的贡献不大。     

基于反相高效液相色谱技术测定市售羊乳粉中蛋白

为鉴别及检测不同地区市售羊乳粉的品质,基于反相高效液相色谱(reversed-phase high performance liquid chromatography,RP-HPLC)技术,将35种市售羊乳粉根据陕西地区和非陕西地区、纯羊乳粉和配方羊乳粉进行分类与检测,研究不同产地、不同种类羊乳粉的差异,对羊乳粉品质进行分析判别。结果表明：对市售羊乳粉乳蛋白进行RP-HPLC测定发现,配方羊乳粉α_s2-酪蛋白(α_s2-casein,α_s2-CN)和β-CN相对含量分别低于纯羊乳粉20%和24%,κ-CN和乳清蛋白相对含量分别高于纯羊乳粉30%和50%;不同地区纯羊乳粉乳蛋白组成及含量相似。因此,通过RP-HPLC可以实现对市售羊乳粉中乳蛋白的测定和质量评价。     

Comparison of Physicochemical and Structural Properties of Acid-Soluble and Pepsin-Soluble Collagens from Blacktip Reef Shark Skin

Fish collagen has been widely used in tissue engineering (TE) applications as an implant, which is generally transplanted into target tissue with stem cells for better regeneration ability. In this case, the success rate of this research depends on the fundamental components of fish collagen such as amino acid composition, structural and rheological properties. Therefore, researchers have been trying to find an innovative raw material from marine origins for tissue engineering applications. Based on this concept, collagens such as acid-soluble (ASC) and pepsin-soluble (PSC) were extracted from a new type of cartilaginous fish, the blacktip reef shark, for the first time, and were further investigated for physicochemical, protein pattern, microstructural and peptide mapping. The study results confirmed that the extracted collagens resemble the protein pattern of type-I collagen comprising the α₁, α₂, β and γ chains. The hydrophobic amino acids were dominant in both collagens with glycine and hydroxyproline as major amino acids. From the FTIR spectra, α helix (27.72 and 26.32%), β-sheet (22.24 and 23.35%), β-turn (21.34 and 22.08%), triple helix (14.11 and 14.13%) and random coil (14.59 and 14.12%) structures of ASC and PSC were confirmed, respectively. Collagens retained their triple helical and secondary structure well. Both collagens had maximum solubility at 3% NaCl and pH 4, and had absorbance maxima at 234 nm, respectively. The peptide mapping was almost similar for ASC and PSC at pH 2, generating peptides ranging from 15 to 200 kDa, with 23 kDa as a major peptide fragment. The microstructural analysis confirmed the homogenous fibrillar nature of collagens with more interconnected networks. Overall, the preset study concluded that collagen can be extracted more efficiently without disturbing the secondary structure by pepsin treatment. Therefore, the blacktip reef shark skin could serve as a potential source for collagen extraction for the pharmaceutical and biomedical applications.     

Antioxidative Effect of Chlorella Pyrenoidosa Protein Hydrolysates and Their Application in Krill Oil-in-Water Emulsions

Chlorella pyrenoidosa is an excellent source of protein, and in this research, we assessed the antioxidant and emulsifying effects of Chlorella protein hydrolysate (CPH) using neutral proteases and alkaline proteases, as well as the properties of CPH-derived krill oil-in-water (O/W) emulsions. The CPHs exhibited the ability to scavenge several kinds of free radicals, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), O₂⁻, hydroxyl, and ABTS. Additionally, the CPHs (5 mg/mL) scavenged approximately 100% of the DPPH and ABTS. The CPHs showed similar emulsifying activities to Tween 20 and excellent foaming activities (max FS 74%), which helped to stabilize the krill oil-in-water emulsion. Less than 10 mg/mL CPHs was able to form fresh krill oil-in-water emulsions; moreover, the CPHs (5 mg/mL) in a krill O/W emulsion were homogenous, opaque, and stable for at least 30 days. Based on their inhibitory effects on the peroxide value (POV) and thiobarbituric acid reactive substances (TRABS), the CPHs were found to be able to inhibit lipid oxidation in both emulsifying systems and krill O/W emulsions. Thus, the CPHs could improve superoxide dismutase (SOD) activities by 5- or 10-fold and decrease the high reactive oxygen species (ROS) level caused by the addition of H₂O₂ in vitro. In conclusion, health-promoting CPHs could be applied in krill oil-in-water emulsions as both emulsifiers and antioxidants, which could help to improve the oxidative and physical stability of emulsions.     

C-端嵌合PRRSV T细胞抗原表位对PCV2 VLPs稳定性的影响

【目的】利用大肠杆菌原核表达系统表达猪圆环病毒2型Cap蛋白及在其C-端嵌合PRRSV T细胞抗原表位的Cap嵌合蛋白,对Cap蛋白形成的病毒样颗粒(VLPs)的稳定性、免疫原性以及C-端嵌合PRRSV T细胞抗原表位VLPs的热稳定性进行研究,为猪圆环病毒2型(PCV2)VLPs疫苗的高效制备及基于Cap VLPs纳米骨架展示技术嵌合疫苗的开发奠定基础。【方法】采用分子生物学方法合成PCV2b型强毒株ZJ的cap基因,在其C-端插入PRRSV T细胞抗原表位T1、T2、T3、T4、T5,构建cap-T1～cap-T5基因;将cap及cap-T1～cap-T5基因与pET28a表达载体连接,构建重组表达载体,转染大肠杆菌ClearColi^TMBL21(DE3)进行诱导表达,并对表达产物的热稳定性及免疫效果进行检测。【结果】实现了Cap蛋白及其C-端嵌合PRRSV T细胞抗原表位的Cap-T1、Cap-T2、Cap-T3、Cap-T4和Cap-T5嵌合蛋白在大肠杆菌中的可溶性表达,并成功观察到了VLPs;表达产物热稳定性分析显示,在60℃处理30 min条件下,Ca...     

硬脂酸-胱氨酸-大豆分离蛋白复合膜的机械特性和吸湿性研究

以硬脂酸作为增塑剂,胱氨酸作为交联剂制备具有一定力学性能和良好抗湿性能的大豆分离蛋白复合膜。将膜放在25℃,相对湿度为50%的干燥器中平衡两天,用质构仪测定膜的抗拉强度(TS),延伸率(E(%))。在水分活度a_w为0.10～0.90的范围内研究了复合膜在25℃的吸湿特性。吸湿速率和吸湿等温线数据分别拟合到Peleg's 方程和GAB(Guggenheim-Anderson-de Boer)模型。结果表明：大豆蛋白复合膜的TS、延伸率E(%)以及吸湿速率随着硬脂酸和胱氨酸的添加比率显著地变化。硬脂酸和胱氨酸的最佳添加比率为40∶60(w/w)(每升蛋白质溶液中加入10 g混合添加剂),此时,大豆蛋白膜的强度比原来提高2倍,并且有最佳的吸湿速率。吸湿数据和GAB 模型有很高的拟合度,拟合系数最高达0.99。     

含肽肝素渣水解物对早期断奶仔猪免疫功能的影响

本试验研究了含肽肝素渣水解物对早期断奶仔猪免疫器官生长发育、血清IgG含量、淋巴细胞数、腹泻指数以及生产性能的影响。试验表明,肝素渣水解后产生的寡肽可促进仔猪免疫器官发育,提高血清免疫球蛋白浓度、猪瘟抗体OD值和血液中淋巴细胞数,提高了断奶仔猪的免疫功能,降低了仔猪的腹泻指数,并能提高仔猪的日增重和饲料转化率。