复合四倍体异育银鲫个体间遗传异质性的研究

用聚丙烯酰胺梯度凝胶电泳,分析比较了４个不同的银鲫雌核发育系,红鲤和复合四倍体异育银鲫鳍的５种不同的同工酶及蛋白表型的差异,表明复合四倍体异育银鲫表型上的差异主要是来自银鲫种内的遗传差异（不同的雌核发育系）。来源于同一个银鲫雌核发育系的复合四倍体异育银鲫,个体间的ＥＳＴ同工酶出现差异,并与父体红鲤的ＥＳＴ同工酶的多态性相关,因此,复合四倍体异育银鲫个体间的异质性也包含了来自父本的遗传影响。在所检测     

甲基毒死蜱对红细胞膜乙酰胆碱酯酶的抑制作用及其与膜脂相互关系

以人红细胞膜为材料,研究了甲基毒死蜱与膜上乙酰胆碱酯酶(AChE)的相互作用及其与膜脂的关系。结果显示,甲基毒死蜱对人红细胞膜AChE有明显的抑制作用,与膜温育30min,其半数抑制浓度约为0.10 mmol/L。动力学分析表明,其抑制作用为非竞争性。0.2％Triton X-100并不改变AChE对甲基毒死蜱的敏感性,亦即AChE上甲基毒死蜱的作用部位与其所处的脂质微环境无关。     

Effects of Allelochemicals on Root Growth and Pod Yield in Response to Continuous Cropping Obstacle of Peanut

Continuous cropping (CC) obstacle is a major threat in legume crops production; however, the underlying mechanisms concerning the roles allelochemicals play in CC obstacle are poorly understood. The current 2-year study was conducted to investigate the effects of different kinds and concentrations of allelochemicals, p-hydroxybenzoic acid (H), cinnamic acid (C), phthalic acid (P), and their mixtures (M) on peanut root growth and productivity in response to CC obstacle. Treatment with H, C, P, and M significantly decreased the plant height, dry weight of the leaves and stems, number of branches, and length of the lateral stem compared with control. Exogenous application of H, C, P, and M inhibited the peanut root growth as indicated by the decreased root morphological characters. The allelochemicals also induced the cell membrane oxidation even though the antioxidant enzymes activities were significantly increased in peanut roots. Meanwhile, treatment with H, C, P, and M reduced the contents of total soluble sugar and total soluble protein. Analysis of ATPase activity, nitrate reductase activity, and root system activity revealed that the inhibition effects of allelochemicals on peanut roots might be due to the decrease in activities of ATPase and NR, and the inhibition of root system. Consequently, allelochemicals significantly decreased the pod yield of peanut compared with control. Our results demonstrate that allelochemicals play a dominant role in CC obstacle-induced peanut growth inhibition and yield reduction through damaging the root antioxidant system, unbalancing the osmolytes accumulation, and decreasing the activities of root-related enzymes.

     

信号分子在生物脱氮中的作用及检测方法

生物脱氮是由微生物主导的地球氮循环中的重要环节之一,主要包括硝化、反硝化和厌氧氨氧化(anaerobic ammonium oxidation,anammox)等过程。在微生物联合作用下,污水中的有机氮及氨氮经一系列作用转化为氮气,这种经济高效、环境友好的处理工艺在世界范围内得到广泛应用。群体感应(quorum sensing,QS)以信号分子为媒介通过改变菌群密度和周围环境变化来调节微生物的各种行为。大量的研究已证实调控QS信号分子在生物脱氮中具有应用潜力。本文介绍了各种信号分子类型,从基因组学、实际应用等方面综述了各类信号分子以及检测方法,同时针对酰基高丝氨酸内酯(acyl homoserine lactones,AHLs)类信号分子在生物脱氮中的作用进行详细介绍。然而不足之处在于信号分子研究只是停留在实验室阶段,仅仅研究了单一信号分子对生物脱氮的影响。未来可将信号分子应用于实际污水,研究多种信号分子共同作用以及多种微生物之间的QS现象。     

屎肠球菌对斑节对虾肠道代谢组学及炎性因子的影响

【背景】屎肠球菌(Enterococcus faecium)作为乳酸菌属的潜在益生菌,因其具有良好的生物学特性在动物养殖中应用广泛,但是屎肠球菌对肠道代谢组学的研究很少。【目的】以斑节对虾为试验动物,初步探究屎肠球菌R8对肠道代谢组学及炎性因子的影响,为屎肠球菌作为益生菌在对虾养殖中的应用提供理论基础。【方法】将400条斑节对虾随机分配,设计饲料中屎肠球菌添加量分别为107、108、109 CFU/g的3个试验组,不添加屎肠球菌为对照组进行试验,养殖周期为28 d。养殖周期结束后测定斑节对虾免疫球蛋白M (immunoglobulin M,IgM)、对虾酚氧化酶(phenoloxidase,PO)、白介素6 (interleukin 6,IL-6)、补体片段3a (complement fragment 3a,C3a)的活性含量并运用LC-MS代谢组学研究肠道内源代谢物的变化,分析差异代谢物和相关的代谢通路。【结果】添加屎肠球菌对斑节对虾炎性因子有积极的影响,增加了斑节对虾体内免疫球蛋白IgM、对虾酚氧化酶、补体片段3a的含量,降低了其体内IL-6的含量,对肠道差异代谢物的分析发现,对...     

伴刀豆球蛋白A和层粘连蛋白与膜受体结合下膜分子运动及微丝组装变化的比较

研究伴刀豆球蛋白A和层粘连蛋白分别与小鼠腹腔巨噬细胞膜受体结合下引起细胞膜分子运动的变化和对微丝组装的影响.结果表明,伴刀豆球蛋白A和层粘连蛋白作用下均导致膜表面蛋白分子的侧向扩散速率减慢,膜脂流动性降低,加快膜内微丝组装并使微丝含量增加.两配体作用下引起细胞上述反应有相似性.     

Universal two-dimensional labelled probe-mediated melting curve analysis based on multiplex PCR for rapid typing of Plasmodium in a single closed tube

Currently, malaria is still one of the major public health problems commonly caused by the four Plasmodium species. The similar symptoms of malaria and the COVID-19 epidemic of fever or fatigue lead to frequent misdiagnosis. The disadvantages of existing detection methods, such as time-consuming, costly, complicated operation, need for experienced technicians, and indistinguishable typing, lead to difficulties in meeting the clinical requirements of rapid, easy, and accurate typing of common Plasmodium species. In this study, we developed and optimized a universal two-dimensional labelled probe-mediated melting curve analysis (UP-MCA) assay based on multiplex and asymmetric PCR for rapid and accurate typing of five Plasmodium species, including novel human Plasmodium, Plasmodium knowlesi (Pk), in a single closed tube following genome extraction. The assay showed a limit of detection (LOD) of 10 copies per reaction and could accurately distinguish Plasmodium species from intra-plasmodium and other pathogens. Additionally, we proposed and validated different methods of fluorescence quenching and tag design for probes that are suitable for UP-MCA assays. Moreover, the clinical performance of the Plasmodium UP-MCA assay using a base-quenched universal probe was evaluated using 226 samples and showed a sensitivity of 100% (164/164) and specificity of 100% (62/62) at a 99% confidence interval, with the microscopy method as the gold standard. In summary, the UP-MCA assay showed excellent sensitivity, specificity, and accuracy for genotyping Plasmodium species spp. Additionally, it facilitates convenient and rapid Plasmodium detection in routine clinical practice and has great potential for clinical translation.     

Resistance of Spiroplasma citri Lines to the Virus SVTS2 Is Associated with Integration of Viral DNA Sequences into Host Chromosomal and Extrachromosomal DNA

Spiroplasmavirus SVTS2, isolated from Spiroplasma melliferum TS2, produces plaques when inoculated onto lawns of Spiroplasma citri M200H, a derivative of the type strain Maroc R8A2. S. citri strains MR2 and MR3, originally selected as colonies growing within plaques on a lawn of M200H inoculated with SVTS2, were resistant to SVTS2. Genomic DNA fingerprints and electrophoretic protein profiles of M200H, MR2, and MR3 were similar, but three proteins present in M200H were missing or significantly reduced in both resistant lines. None of these three polypeptides reacted with antiserum against S. citri membrane proteins, indicating that they probably are not surface-located virus receptors. Electroporation with SVTS2 DNA produced 1.5 x 10(sup5) transfectants per (mu)g of DNA in M200H but none in MR2 or MR3, suggesting that resistance may result from inhibition of viral replication. The digestion patterns of the extrachromosomal double-stranded (ds) DNA of these lines were similar. Three TaqI fragments of MR2 extrachromosomal DNA that were not present in M200H extrachromosomal DNA hybridized strongly to an SVTS2 probe, and two of these fragments plus an additional one hybridized with the MR3 extrachromosomal DNA, indicating that a fragment of SVTS2 DNA was present in the extrachromosomal ds DNA of MR2 and MR3 but not of M200H. When the restricted genomes of all three lines were probed with SVTS2 DNA, strong hybridization to two EcoRI fragments of chromosomal MR2 and MR3 DNA but not M200H DNA indicated that SVTS2 DNA had integrated into the genomes of MR2 and MR3 but not of M200H. When MR3 extrachromosomal ds DNA containing a 2.1-kb SVTS2 DNA fragment was transfected into M200H, the transformed spiroplasmas were resistant to SVTS2. These results suggest that SVTS2 DNA fragments, possibly integrated into the chromosomal or extrachromosomal DNA of a previously susceptible spiroplasma, may function as viral incompatibility elements, providing resistance to superinfection by SVTS2.