超声波辅助提取菜用黄麻色素及其抗氧化活性的研究

采用单因素试验分析和正交试验设计,研究超声波辅助提取菜用黄麻色素的工艺条件,用Fenton法测定菜用黄麻色素的抗氧化活性.结果表明:(1)影响色素提取的因素为料液比>超声频率>提取温度>提取时间;(2)提取的最佳条件为使用60∶40(V/V)的0.1%盐酸和95%乙醇作为提取剂,料液比1∶80(g.mL-1),超声频率为中频,提取时间30 min,提取温度为60℃;以此工艺条件提取色素的产率达25.04%;(3)该色素溶液还原力强,具有清除超氧阴离子自由基O2.-和.OH的活性,在色素浓度为0.20 g.L-1时,对超氧阴离子自由基O2.-的清除率为70.11%,对.OH的清除率为83%.     

滇型杂交稻不育系和恢复系的籼粳分化特点

用19个籼粳分化特异性随机引物分析了滇型杂交稻10个不育系和38个忧愁系的分化特点。结果表明：从所分析的34个籼粳位点看，滇型不育系和恢复系以粳稻亲缘为主，但都含有籼稻亲缘，其中不育系所含籼稻成分在4%-24%，恢复系籼稻成分在4%-36%；按UPGMA法聚类，供试不育系和恢复系全部归于粳稻类。     

外场强化提取银杏总黄酮及抗氧化性能研究

[目的]寻求银杏叶总黄酮外场辅助提取法的最佳提取工艺。[方法]用正交试验设计优选出银杏叶总黄酮的外场(微波场、超声波场)辅助提取工艺,并采用DPPH检测法对最佳工艺条件下的微波、超声波提取物的抗氧化性进行了比较研究。[结果]微波辅助提取银杏总黄酮的最佳工艺条件为:提取时间15min,乙醇浓度80%,提取温度70℃,料液比1∶25;超声波辅助提取银杏总黄酮的最佳工艺条件为:提取温度50℃,乙醇浓度80%,料液比1∶20,提取时间40min。在最佳工艺条件下微波法和超声波法提取得率分别为4.09%和3.68%,微波法所用时间仅为超声波法的1/3。[结论]微波法是提取银杏叶总黄酮的较好方法,超声波法提取物的抗氧化能力强于微波提取物。     

Factors affecting the virulence of Ralstonia solanacearum and its colonization on tobacco roots

Tobacco bacterial wilt caused by Ralstonia solanacearum is a serious disease affecting tobacco cultivation in southwest China. The response surface methodology was employed to evaluate the optimal conditions of tobacco bacterial wilt, and green fluorescent protein gene (gfp) labelling was applied to monitor the location and survival dynamics of R. solanacearum (Rs::gfp) on tobacco roots and in soil under these optimal conditions. The results showed that the highest wilt incidence was 91.13%, which occurred when the population reached 6.6 × 10⁶ CFU/g soil, the temperature was 30.55 °C, and the humidity was >81.42%. The Rs::gfp densely colonized the root tips and root hairs, and cells of Rs::gfp were observed intermittently in the elongation zone or at the point of the emerging lateral roots. The Rs::gfp number in the rhizosphere soil was 10.75‐, 73.13‐ and 74.86‐times higher than that in the bulk soil at 10, 15 and 20 days after transplantation, respectively. Increased colonization by Rs::gfp was related to the population of the pathogen, the environmental temperature and the humidity in the soil. These three conditions determined whether R. solanacearum would induce tobacco wilt. This is the first study to investigate factors affecting the virulence of a tobacco wilt bacterial pathogen, which is important for conducting field diagnosis and biocontrol of tobacco bacterial wilt.     

不同转化方法培育无抗性选择标记转基因水稻效率的比较

 为研究不同的转化方法培育无抗性选择标记转基因水稻的效果,以4个籼粳稻品种为受体材料,比较了用农杆菌介导的双菌双载体和双T DNA单载体两种共转化技术的共转化频率及随后获得的无抗性选择标记基因转化子的效率。结果表明,在双菌双载体介导的转化中,4个水稻品种的平均共转化频率为10.1%,其中55.6%的共转化植株自交后代中可筛选出无抗性选择标记的转基因水稻植株。在单载体双 T DNA介导的共转化中,平均共转化频率为45.0%,从其中600%的共转化植株自交后代中可获得无抗性选择标记的转基因植株,即双T DNA单载体法的去选择标记的效率（270%）要较双菌双载体法（5.6%）高。     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

Comparative activity of Choristoneura fumiferana nucleopolyhedrovirus propagated in different hosts

The biological activity of the Ireland strain of Choristoneura fumiferana (Clem) nucleopolyhedrovirus (CfMNPV) propagated in different hosts was determined to provide the basis upon which genetically modified CfMNPV, or other naturally occurring isolates, should be compared. Occlusion bodies (OB) derived from CF-203 cells were significantly larger and more pathogenic than those propagated in vivo when tested against the fifth larval instar of C fumiferana (Clem) and C occidentalis Freeman. The dose-responses (LD50 and LD95, expressed as occlusion bodies per larva) of C fumiferana larvae to in vitro-propagated OBs were 274 and 5785, respectively. The values of LD50 and LD95 to C occidentalis larvae were 19 and 118, respectively. There were no significant differences in pathogenicity or size when OBs propagated in C fumiferana larvae were tested against either insect species, nor were there significant differences for OBs propagated in C occidentalis larvae. The LD50 and LD95 of in vivo-produced OBs to C fumiferana were 925 and 61988, respectively. The LD50 and LD95 to C occidentalis were 50 and 453, respectively. OBs propagated in vitro had a mean volume of 13.13 microm3, whereas those propagated in vivo ranged from 0.84 to 1.41 microm3. The median survival time-responses (ST50) of fifth-instar C fumiferana or C occidentalis larvae to OBs propagated in vivo were not significantly different from those propagated in vitro at the dosage levels tested. Values of ST50 of C fumiferana larvae to in vitro- and in vivo-produced OBs at dosages causing less than 50% mortality rangedfrom 9.6 to 9.8 days post-inoculation (dpi), whereas a LD95 dose resulted in ST50 values ranging from 7.3 to 7.7 days. ST50 values of C occidentalis larvae at dosages causing less than 50% mortality ranged from 9.8 to 10.2 dpi, whereas a LD95 dose resulted in ST50 values ranging from 9.5 to 9.8 dpi. The median feeding cessation time-response (FT50) of fifth-instar C fumiferana larvae to OBs propagated in vitro (5.7 days) was not significantly different from the FT50 of those propagated in vivo in either insect species (5.3 and 5.7 days) at the dosage level tested (LD95). No significant differences in FT50 values were observed between OBs propagated in either larval host. The FT50 of C occidentalis larvae to OBs propagated in vitro (7.7 days) was not significantly different from that to those propagated in vivo in C occidentalis larvae (7.6days), but somewhat different (7.2 days) from that to those propagated in C fumiferana larvae. Results indicate that CfMNPV can be propagated in vivo in either C fumiferana or C occidentalis larvae (or sequentially through both) without alteration in infectivity, although the use of the CF-203 cell line yields the most biologically active OBs.     

小麦穗长性状基因的发掘与标记开发

【目的】挖掘与利用小麦穗长控制基因,开发与之紧密连锁的KASP标记,为小麦分子标记辅助育种奠定分子基础。【方法】以Avocet为母本、Chilero为父本,构建含有164个家系的F₆ RIL群体,利用55K SNP芯片,结合5个穗长表型环境（2019年河南省孟津县、2019年河南科技大学农场、2019年河南省洛宁县、2020年河南省孟津县、2020年河南科技大学农场）及各环境穗长均值进行数量性状位点(quantitative trait locus,QTL)定位,对定位到的主效QTL开发KASP标记,并在130份小麦自然群体中进行验证。【结果】共定位到11个控制穗长性状的QTL位点,有7个主效QTL,分别为QSl.haust-2AL、QSl.haust-2DS、QSl.haust-5AL1、QSl.haust-5DL、QSl.haust-7BL、QSl.haust-2AS和QSl.haust-4DL,表型贡献率为4.22%~30.94%,其中QSl.haust-5AL1在3个环境中表现稳定且为主效QTL,其表型贡献率为4.22%~19.10%;另有4个微效QTL位点,分别为QSl.haust-2BL、QSl.haust-3AL、QSl.haust-3DS和QSl.haust-5AL2,表型贡献率为4.70%~7.55%。依据控制穗长的主效QTL位点QSl.haust-5AL1和QSl.haust-7BL的侧翼标记,开发了相应的KASP分子标记KASP-QSl.haust-5AL1和KASP-QSl.haust-7BL1,在130份小麦自然群体中检测验证,其中KASP-QSl.haust-5AL1标记筛选出的2种基因型,穗长分别为10.93和10.17 cm,经t检验,P值为0.045,差异显著;KASP-QSl.haust-7BL1标记筛选出的2种基因型,穗长分别为10.90和10.26 cm,经t检验,P值为0.048,差异显著。【结论】挖掘的控制小麦穗长的主效QTL和开发的KASP分子标记,可以用于该性状的基因克隆与分子标记辅助育种。     

生物大分子标记物检测在环境监测中的应用

生物大分子标记物是指生物体内的一些对外界环境变化敏感并能产生一些可检测变化的大分子物质,这些大分子物质能够反映环境变化对生物体的影响。随着社会对环境保护的日益重视和分子生物学技术的发展,将生物大分子标记物的检测应用到环境监测中已经成为一种趋势。生物大分子标记物检测由于其测定指标全面、准确、系统且具有特异性等优点,近十几年来作为污染物暴露和毒性效应的早期预警工具已被广泛应用于环境评价中。本文对一些主要的生物大分子标记物及其检测技术在环境监测中的应用状况及应用前景进行综述,旨在为生物大分子标记技术在环境检测实际操作中的应用提供参考依据。