解淀粉芽孢杆菌诱变育种及其突变株在降低酱油中氨基甲酸乙酯的应用

【目的】通过诱变育种提高解淀粉芽孢杆菌JY06利用精氨酸的能力,并将其用于降低酱油中的氨基甲酸乙酯及前体,从而提高酿造酱油的安全性。【方法】采用等离子诱变和紫外诱变两种诱变育种方法对解淀粉芽孢杆菌JY06进行突变,应用高通量筛选手段获得具有高精氨酸利用能力的突变株,验证突变株降低酱油中氨基甲酸乙酯的能力。【结果】获得了12株精氨酸利用能力提高的突变株,与出发菌株JY06相比,突变株C12和E6可使酱油中瓜氨酸含量分别降低了15.6%和14.7%,EC的含量分别降低了19.3%和13.1%。【结论】通过等离子诱变和紫外诱变进一步提高了解淀粉芽孢杆菌JY06降低酱油中EC及其前体瓜氨酸的能力,具有控制或减少酱油中生物危害物的应用潜力。     

The chemiluminescence immunoassay for aflatoxin B1 based on functionalized magnetic nanoparticles with two strategies of antigen probe immobilization

A rapid and sensitive chemiluminescence immunoassay (CLIA) based on magnetic nanoparticles (MNPs) was developed to detect aflatoxin B1 (AFB1), which is a potent carcinogen in nature. We prepared monodisperse MNPs (300 nm in diameter) according to the solvothermal synthesis reaction and the MNPs were coated with silica by the Stöber method. Triethox was used as a one‐step carboxylation reagent, and 3‐aminopropyltriethoxysilane (APTES) an amination reagent, to modify the MNPs. We prepared two types of solid phase antigens using the above synthesized functionalized MNPs coupled with the later prepared AFB1‐oxime active ester and the purchased BSA–AFB1 respectively. 2′,6′‐dimethylcarbonylphenyl‐10‐sulfopropylacridinium‐9‐carboxylate 4′‐N‐hydroxysuccinimide (4′‐NHS) ester (NSP–DMAE–NHS), as a novel luminescent reagent, was used to label anti‐AFB1 antibodies. The two CLIA calibration curves based on the two types of solid phase antigens were obtained and compared. The acquired limit of detection (LOD) was about 0.001 ng/mL for the two functionalized MNPs‐based immunoassays, and the half maximal inhibitory concentration (IC₅₀) was 0.51 ng/mL for the MNPs–AFB1‐based method and 0.72 ng/mL for the MNPs–BSA–AFB1‐based method.     

葛洲坝下中华鲟繁殖生物学特性及其人工繁殖效果

以1998—2004年(除2002年外)间从葛洲坝下产卵场捕获的57尾(雌36尾,雄21尾)中华鲟人工繁殖群体为材料,研究了中华鲟人工繁殖群体的繁殖生物学特性.结果表明:1998—2004年间中华鲟雌鲟体长240～320cm,体质量140～432kg,年龄15～30龄;雄鲟体长153～284cm,体质量70～244kg,年龄12～26龄.雌鲟催产率93·1%,雄鲟催产率100%.卵子可明显分为7种颜色;绝对怀卵量为20～59万粒,平均35·8万粒;相对怀卵量820～3020粒·kg-1,平均1590粒·kg-1.精液明显分为4种颜色;绝对采精量1000～5952ml,平均2597·8ml;相对采精量1·25～31·24ml·kg-1,平均13·3ml·kg-1.多年人工催产受精率平均达到63·7%,孵化率达到48·1%,6年共孵化出苗476·2万尾,保证了人工繁殖放流的实施.资料对比显示,中华鲟繁殖群体自然繁殖力大幅下降.     

消杀型纳米催化剂抗病毒作用的研究

本文探讨112种消杀型纳米催化剂吸附与灭活病毒的功效,为开发新型抗病毒纳米材料提供理论依据。我们将各种纳米催化剂与副流感病毒、人疱疹病毒Ⅰ型、腺病毒1型及5型作用一定时间后,分别以血凝试验及观察CPE变化的方法判断纳米材料对各种病毒的吸附与灭活作用,并在电子显微镜下观察纳米材料对病毒的吸附情况。结果在所检测的112种纳米催化剂中,用血凝试验分别筛选出强吸附力催化剂 29 种、中吸附力催化剂 36 种、弱吸附力催化剂47种。其中,13 种强吸附力催化剂对副流感病毒的吸附率在 87.5%~93.75%之间,并以 AB 24的抗病毒效果最好。     

31例非特异性阴道炎病人阴道微生物群的研究

本文对31例非特异性阴道炎病人和31例正常人阴道微生物群进行定性、定量分析.结果表明,阴道炎病人的阴道乳杆菌的平均浓度明显低于正常人,而肠杆菌科、葡萄球菌、棒状杆菌、类杆菌属、支原体却明显增多,阴道炎病人未发现特异性病原体,菌群失调可能是其发病因素。乳杆菌为阴道正常优势菌,对改善阴道的微环境,防止条件致病菌引起的内源性感染具有重要的生理作用。     

慢性阻断血管紧张素Ⅱ1型受体不能完全防止模拟失重大鼠血管的适应性结构变化

我们以前的工作提示,在模拟失重所引起的血管区域特异性适应变化中,局部肾素．血管紧张素系统（local reninangiotensin system,L-RAS）可能发挥关键调控作用。本文以losartan慢性阻断血管紧张素Ⅱ1型受体（angiotensin Ⅱtypelreceptor,AT1R）,观察模拟失重是否仍能引起血管的这种适应性改变,并检测大血管管壁L-RAS主要成分的表达是否也发生相应变化。以尾部悬吊大鼠模型模拟失重的生理影响。制作基底动脉、胫前动脉、颈总动脉和腹主动脉的HE染色切片,在光学显微镜下进行形态观测：用免疫组织化学技米测量颈总动脉和腹主动脉壁的血管紧张素原（angiotensinogen,AGT）及AT-R的表达变化。结果表明：4周模拟失重引起大鼠基底动脉中膜和颈总动脉管壁各平滑肌肌层肥厚,而胫前动脉和腹主动脉则发生萎缩性改变;给予losartan4周引起上述4种血管皆发生萎缩性变化;阻断AT1R,模拟失重仍然能引起基底动脉、颈总动脉发生相对肥厚性改变和腹主动脉萎缩加重。4周模拟失重还引起颈总动脉壁中AGT和AT1R表达上调,而腹主动脉壁及血管周围组织中AGT和AT1R表达下调;给予losartan4周仅引起腹主动脉壁中AGT和AT1R表达减少;阻断AT1R,模拟失重使腹主动脉壁AT1R表达进一步减少。结果提示,4周模拟失重引起大鼠脑、颈部与后身大、中动脉血管的形态结构改变和L-RAS主要成分表达发生上调或下调,血管L-RAS在其中可能发挥关键性调控作用;但在慢性阻断AT1R的条件下,其它调控机制仍可能在脑血管适应性调节中发挥一定作用。     

Effects of size,neighbors, and site condition on tree growth in a subtropical evergreen and deciduous broad‐leaved mixed forest,China

Successful growth of a tree is the result of combined effects of biotic and abiotic factors. It is important to understand how biotic and abiotic factors affect changes in forest structure and dynamics under environmental fluctuations. In this study, we explored the effects of initial size [diameter at breast height (DBH)], neighborhood competition, and site condition on tree growth, based on a 3‐year monitoring of tree growth rate in a permanent plot (120 × 80 m) of montane Fagus engleriana–Cyclobalanopsis multiervis mixed forest on Mt. Shennongjia, China. We measured DBH increments every 6 months from October 2011 to October 2014 by field‐made dendrometers and calculated the mean annual growth rate over the 3 years for each individual tree. We also measured and calculated twelve soil properties and five topographic variables for 384 grids of 5 × 5 m. We defined two distance‐dependent neighborhood competition indices with and without considerations of phylogenetic relatedness between trees and tested for significant differences in growth rates among functional groups. On average, trees in this mixed montane forest grew 0.07 cm year^?1 in DBH. Deciduous, canopy, and early‐successional species grew faster than evergreen, small‐statured, and late‐successional species, respectively. Growth rates increased with initial DBH, but were not significantly related to neighborhood competition and site condition for overall trees. Phylogenetic relatedness between trees did not influence the neighborhood competition. Different factors were found to influence tree growth rates of different functional groups: Initial DBH was the dominant factor for all tree groups; neighborhood competition within 5 m radius decreased growth rates of evergreen trees; and site condition tended to be more related to growth rates of fast‐growing trees (deciduous, canopy, pioneer, and early‐successional species) than the slow‐growing trees (evergreen, understory, and late‐successional species).     

Phosphorus accumulates faster than nitrogen globally in freshwater ecosystems under anthropogenic impacts

Combined effects of cumulative nutrient inputs and biogeochemical processes that occur in freshwater under anthropogenic eutrophication could lead to myriad shifts in nitrogen (N):phosphorus (P) stoichiometry in global freshwater ecosystems, but this is not yet well‐assessed. Here we evaluated the characteristics of N and P stoichiometries in bodies of freshwater and their herbaceous macrophytes across human‐impact levels, regions and periods. Freshwater and its macrophytes had higher N and P concentrations and lower N : P ratios in heavily than lightly human‐impacted environments, further evidenced by spatiotemporal comparisons across eutrophication gradients. N and P concentrations in freshwater ecosystems were positively correlated and N : P was negatively correlated with population density in China. These results indicate a faster accumulation of P than N in human‐impacted freshwater ecosystems, which could have large effects on the trophic webs and biogeochemical cycles of estuaries and coastal areas by freshwater loadings, and reinforce the importance of rehabilitating these ecosystems.     

藏药匙叶翼首草高频组织培养再生体系优化研究

以匙叶翼首草种子为材料,探索种子最佳消毒方法,对影响无菌苗外植体愈伤组织诱导、增殖及植株再生的因素进行了研究。结果表明:(1)剥去外种皮的种子,经75%乙醇1min+0.1%HgCl_27min+50%多菌灵500倍液30min消毒后,在1/2 MS培养基中的发芽率达60.67%,无污染。(2)无菌苗的叶片和茎段都适宜诱导愈伤组织,在培养基MS+5.0mg·L~(-1) 6-BA+2.0mg·L~(-1) 2,4-D中可在10d内诱导出生长旺盛的愈伤组织,愈伤诱导率分别为84.00%、97.33%。(3)适宜的愈伤组织增殖培养基为MS+3.0mg·L~(-1) 6-BA+2.0mg·L~(-1) IAA,培养20d的叶片和茎段愈伤组织的生长率分别为74.37%、70.52%。(4)适宜的丛生芽诱导培养基为MS+3.0mg·L~(-1) 6-BA+2.0mg·L~(-1) IAA+250mg·L~(-1) L-脯氨酸+150mg·L~(-1)水解酪蛋白,30d后茎段和叶片的丛生芽发生率分别达到100%、94.44%。(5)再生苗在1/2 MS+0.5mg·L~(-1) NAA培养基中生根培养30d,生根率为100%。匙叶翼首草高效稳定的再生体系为保护其野生资源和工厂化育苗提供了有效途径。