鱼体内环境激素DMP和DEP的检测方法

建立同时检测鲫(Carassuys auratus Linnaeus)血浆和肌肉中邻苯二甲酸二甲酯(DMP)和邻苯二甲酸二乙酯(DEP)的高效液相色谱方法,进行初步的代谢动力学研究。血浆样品经液-液萃取,肌肉样品经液-液萃取和固相小柱处理后,以乙腈∶水=40∶60(V/V)为流动相,流速1.0mL/min,采用SHIMADZU ODS柱(150mm×4.6mm;i.d.,5μm)色谱柱分离。测定鲫经口染毒后血浆和肌肉中DMP和DEP的浓度。结果表明,标准曲线线性范围为0.05~10.0μg/mL,线性关系良好(r>0.99),定量限为0.05μg/mL,回收率95%以上,日内变异系数和日间变异系数均低于15%。经口染毒48h内,鲫血浆和肌肉中均能检测到DMP和DEP的残留。该法操作简便、快速、灵敏、准确,已经初步用于鲫血浆和肌肉中DMP和DEP的代谢动力学和残留研究。     

The impact of redox agents on further dough development,relaxation and elastic recoil during lamination and fermentation of multi-layered pastry dough

The role of gluten proteins during lamination and fermentation of multi-layered wheat flour pastry dough was examined by including oxidizing or reducing agents in the recipe to respectively strengthen or weaken the gluten protein network. Pastry burst rig textural measurements showed that dough strength increases during lamination up to 16 fat layers. However, further lamination up to 64 and 128 fat layers decreases the dough strength, most likely due to destruction of layer integrity. Redox agents strongly affect dough strength. Furthermore, fermentation and spread tests showed that they strongly influence elastic recoil immediately after lamination and during relaxation. Moreover, elastic recoil consistently occurs to a greater extent in the final direction of sheeting. None of the observed changes in dough strength and relaxation behaviour could be linked to changes in the levels of protein extractable in sodium dodecyl sulfate containing medium (SDS-EP). This suggests that changes occur preferentially either within the SDS-extractable or within the non-SDS-EP fraction and that they do not render non-extractable protein fractions extractable or vice versa. Furthermore, elastic recoil is most likely caused by reformation of inter- and intramolecular hydrogen bonds and hydrophobic interactions.     

mgr-mir-9 implicates Meloidogyne graminicola infection in rice by targeting the effector MgPDI

MicroRNAs (miRNAs), a class of small non-coding RNAs, are crucial endogenous gene regulators in a range of animals, including plant-parasitic nematodes. Meloidogyne graminicola is an obligate sedentary endoparasite of rice and causes significant yield losses. A number of studies focused on the roles of M. graminicola effectors during the parasitic process; however, how nematode miRNAs regulate its effectors needs elucidating. In this research, we analyzed a cluster of M. graminicola miRNAs obtained at the second-stage juveniles (J2s) stage that are closely linked to the regulation of M. graminicola effectors. There are 49 767 105 total clean reads obtained from three libraries. A total of 233 known miRNAs and 21 novel miRNAs were identified. Among the known miRNAs, mgr-lin-4, mgr-mir-1, mgr-mir-100, mgr-mir-86, mgr-mir-279, mgr-mir-87, mgr-mir-71, mgr-mir-9, mgr-mir-50, mgr-mir-72, and mgr-mir-34 are the most abundant 11 miRNAs families. Moreover, the expression levels of selected miRNAs were validated by real-time quantitative PCR. We hypothesized that these miRNAs might regulate the expression of secreted effectors during the J2s stage to facilitate its infection. Consistent with this, we found that mgr-mir-9 targets MgPDI, an important M. graminicola effector mRNA. In addition to that, J2s treated with mgr-mir-9 mimics showed down-regulation of MgPDI expression and reduced reproductive ability, alluding mgr-mir-9 is involved in nematode infection. These results provide novel insight into the regulatory functions of M. graminicola miRNAs during the infection and identify miRNAs and their effector targets as potential key management targets to limit parasite survival during the early stages of infection.     

橡胶初加工废水污染土壤的微生物固定化修复

橡胶初加工废水产生大量富含高有机质,并具有高粘度、酸性和高有机物等特点。因其处理成本较高且经常存在厌氧处理失效导致后端废水处理不达标、甚至有较多废水直接排出而污染了周边土壤,但目前对于橡胶初加工废水污染土壤的危害及修复关注度不够。前期从天然橡胶加工厂附近的受污染土壤中分离和驯化出了一种以芽孢杆菌为优势菌属的高效降解菌群命名为WR-2。WR-2在橡胶初加工废水降解方面表现出优异的性能,但在应用上WR-2需要一定的准备期及环境适应期。因此,本研究采用包埋法,以海藻酸钠–木薯渣生物质炭、甘蔗渣、椰糠3种载体材料及1.5%、2%两种材料浓度下进行固定化小球制备实验,同时进行橡胶初加工废水中典型的胶清废水污染土壤的固定化小球模拟修复实验,研究WR-2的包埋固定化基础性能及其生物修复能力。经过6组固定化微球在机械性能和对污染土壤的修复效果方面比较发现,2%椰糠改良固定化微球不仅具有较优良的机械性能,在模拟修复实验中对污染土壤的有机质（TOC）降解率高达（96.7%）,土壤二硫化四甲基秋兰姆（TMTD）在14 d全部降解,且使土壤pH从4.42调节至中性,土壤阴阳离子总数降低并具有良好的微生物活性。2%椰糠固定化小球极大地改善了土壤微观结构及土壤通气性和排水性。因此,海藻酸钠2%椰糠作为WR-2的固定化小球制备方式,对优化橡胶初加工废水污染土壤的生物修复能力具有效果优和即时应用的作用。     

龙竹半纤维素的提取分离及结构表征

龙竹竹粉经脱蜡及脱淀粉后,再经亚氯酸钠脱木素制得综纤维素,进一步用二甲亚砜(DMSO)以及KOH溶液提取,经乙醇沉淀后制得半纤维素H1和H2,得率分别为18.7%和39.8%。对半纤维素组分H1和H2进行糖分析、红外光谱以及核磁共振分析。结果表明,龙竹半纤维素为乙酰化的L-阿拉伯糖基-4-O-甲基葡萄糖醛酸木聚糖,其中阿拉伯糖连接在木聚糖主链的C-3位,4-O-甲基葡萄糖醛酸连接在木聚糖主链的C-2位,而乙酰基连接在木聚糖主链的C-2位或C-3位。