Arbuscular mycorrhizal fungi (AMF) are important in the phytoremediation of cadmium (Cd). Improving photosynthesis under Cd stress helps to increase crop yields. However, the molecular regulatory mechanisms of AMF on photosynthetic processes in wheat (Triticum aestivum) under Cd stress remain unclear. This study utilized physiological and proteomic analyses to reveal the key processes and related genes of AMF that regulate photosynthesis under Cd stress. The results showed that AMF promoted the accumulation of Cd in the roots of wheat but significantly reduced the content of Cd in the shoots and grains. The photosynthetic rates, stomatal conductance, transpiration rates, chlorophyll content, and accumulation of carbohydrates under Cd stress were increased by AMF symbiosis. Proteomic analysis showed that AMF significantly induced the expression of two enzymes involved in the chlorophyll biosynthetic pathway (coproporphyrinogen oxidase and Mg-protoporphyrin IX chelatase), improved the expression of two proteins related to CO2 assimilation (ribulose-1,5-bisphosphate carboxylase and malic enzyme), and increased the expression of S-adenosylmethionine synthase, which posi-tively regulates abiotic stress. Therefore, AMF may regulate photosynthesis under Cd stress by promoting chlorophyll biosynthesis, carbon assimilation, and S-adenosylmethionine metabolism.

为研究丛枝菌根真菌(AMF)是否通过对镉(Cd)胁迫小麦褪黑素(MLT)代谢的调节作用来增强小麦Cd耐性,以小麦和摩西球囊霉为试验材料,采用土培方法,研究Cd胁迫下接种AMF对小麦MLT代谢的调节作用.结果显示,Cd胁迫下接种AMF处理与同浓度Cd胁迫处理相比,小麦叶片5-羟色胺(5-HT)、5-甲氧基色胺(5-MT)、MLT及2-羟基褪黑素(2-HMT)含量均有不同程度的增加,MLT合成相关酶及分解相关酶的活性均有不同程度的提高,MLT的合成酶基因TaASMT1、TaASMT2、TaCOMT、TaSNAT及MLT的分解基因Ta2-ODD的表达水平均有不同程度上调.表明AMF可以通过上调Cd胁迫小麦内源MLT代谢相关基因表达水平来提高相应酶的活性,促进MLT的合成,同时加速MLT分解为2-HMT,缓解Cd胁迫造成的氧化伤害,增强小麦的Cd耐性.

对小麦抗性淀粉和马铃薯抗性淀粉结构特征及体外消化性进行研究.结果表明,与小麦抗性淀粉相比,马铃薯抗性淀粉直链淀粉含量更高,分子质量分布更集中,热稳定性更高.两种抗性淀粉粒径相差不大,均为C型结构,化学结构相似,没有基团差异.小麦抗性淀粉分子颗粒完整,表面光滑,呈不规则的椭圆形,马铃薯抗性淀粉分子为不规则多面体,分子表面粗糙,有凹陷,且有少量的层状起伏.体外消化实验表明:马铃薯抗性淀粉具有更强的抗消化能力,血糖指数分别为40.62、40.50(GI＜55),属于低GI食品.相关性分析结果为抗性淀粉体外消化率与其直链淀粉含量、碘吸收峰负相关,与其结晶度、热焓值显著负相关,与比表面积正相关.

为了探究丛枝真菌对镉(Cadmium,Cd)胁迫小麦的修复作用,以小麦(Triticum aestivum L.)品种百农207和摩西球囊霉菌(Glomus mosseae,Gm)为材料,采用土培试验方法,研究了丛枝真菌对Cd胁迫小麦幼苗类黄酮含量、一氧化氮(Nitric oxide,NO)含量、过氧化氢(Hydrogen peroxide,H2 O2)浓度、硝酸还原酶(Nitrate reductase,NR)活性的影响.结果显示,5和10 mg·kg-1 Cd胁迫接种丛枝真菌小麦幼苗与同质量浓度Cd胁迫小麦幼苗相比,类黄酮含量上升,但差异不显著;NR活性显著上升,分别是5和10 mg·kg-1 Cd胁迫小麦幼苗的1.94,2.03倍;NO含量显著上升,分别比5和10 mg·kg-1 Cd胁迫小麦幼苗提高了50.70％,35.96％;H2 O2含量显著下降,分别比5和10 mg·kg-1 Cd胁迫小麦幼苗下降了34.77％,36.07％.结果表明,接种丛枝真菌可以通过提高类黄酮、NO含量和NR活性,降低Cd胁迫产生的过量活性氧,缓解Cd胁迫造成的氧化伤害.

目的 研究马铃薯抗性淀粉的结构特征与体外消化特性.方法 以马铃薯淀粉为对照,采用红外光谱仪、X射线衍射仪技术(X-ray diffraction,XRD)、差示扫描量热法(differential scanning calorimetry,DSC)等手段研究马铃薯抗性淀粉的碘吸收特性、颗粒形貌、晶型结构形态、热特性.通过模拟体外消化评价马铃薯抗性淀粉的消化性能.结果 马铃薯淀粉和抗性淀粉碘吸收曲线最大吸收峰均在580～600 nm,马铃薯抗性淀粉分子量分布更集中.马铃薯淀粉为B型结晶结构,马铃薯抗性淀粉为C型结晶结构.扫描电子显微镜(scanning electron microscope,SEM)观察显示,马铃薯淀粉分子颗粒完整,表面光滑,整体呈不规则的椭圆形;马铃薯抗性淀粉分子为不规则多面体,分子表面粗糙、有凹陷,且有少量的层状起伏;红外光谱分析表明抗性淀粉未出现新的基团.DSC检测发现,马铃薯抗性淀粉的热稳定性更高;马铃薯淀粉和抗性淀粉酶解前2 h内消化速率迅速增加,酶解2 h后速率减慢,消化速率逐渐趋于平缓,血糖指数分别为70.42、40.50.结论 马铃薯抗性淀粉具有较致密的结晶结构和较强的酶抗性,抗消化性显著.

研究了添加芹菜浆、黄油、蛋液、食盐对饼干感官品质和质构特性的影响,通过正交试验优化得到芹菜饼干的最优配方是:芹菜浆25.7％、黄油16％、蛋液16.1％、食盐1.4％.采用优化配方制备的饼干风味独特,质地细腻,口感酥松,同时饼干中的膳食纤维含量提高约20.83倍,为推动芹菜饼干的工业化生产及获得高食用品质的纤维素面制品提供参考.

以小麦(Triticum aestivum L.)为材料,采用土培试验,研究了接种丛枝菌根真菌对镉(Cd)胁迫小麦幼苗超氧阴离子产生速率、球囊霉素相关土壤蛋白(GRSP)、根内Cd含量、植物螯合肽(PC)含量及植物螯合肽合成酶(PCS)活性的影响.结果表明,Cd胁迫未接种丛枝菌根真菌造成小麦叶片超氧阴离子产生速率、PC含量、PCS活性及根内Cd含量显著增加,且随着胁迫质量分数的增加而极显著上升;胁迫质量分数下接种丛枝菌根真菌较未接种相比,小麦叶片内超氧阴离子产生速率、PC含量和PCS活性降低,根际土壤GRSP及根内Cd含量则极显著升高.本研究表明,接种丛枝菌根真菌可通过土壤GRSP鳌合作用将部分Cd固定在土壤中,同时增加根系中Cd的含量,缓解Cd胁迫对叶片造成的氧化伤害,解除Cd的部分毒性.

利用马铃薯离体叶柄接种方法分别比较了5种不同接种浓度、4个不同接种时间的接种效果的差异,并利用该方法鉴定了14份马铃薯品种对黑胫病的抗性.在试验中发现,使用马铃薯黑胫病菌浓度为103CFU·mL-1,并且在接种马铃薯离体叶柄后36 h记录统计的接种效果较好.同时,利用该方法对14份马铃薯品种进行接种鉴定,鉴定出高抗品种2份、中抗品种5份、中感品种3份、高感品种4份,并且与传统主茎注射接种方法进行了比较,发现2种方法的抗性鉴定结果相近.因此利用离体叶柄接种方法鉴定出的马铃薯品种的抗性可为今后马铃薯黑胫病抗性育种提供一定的理论支持.

In this study,ARTP(atmospheric pressure and room temperature plasma,ARTP) method was used to obtain rapid mutagenesis of Bacillus subtilis E7 in atmospheric pressure and room temperature,to screen strain with high yield of surfactin.Several methods such as appearance screening,determination of diameter of hemolytic circle,culture in Microflask,detection by multifunctional enzyme standard detector,and shake flask test were combined to improve screening throughput and speed up screening process.A high-throughput screening system for mutant strain with high yield of surfactin was preliminarily built.High performance liquid chromatography (HPLC) was used to detect target product.After mutagenesis for 220 s,Bacillus subtillus strain SF90-5 with good genetic stability was obtained.Its surfactin yield increased to 0.8 g/L,which was 5 times of that of the original strain.Mutagenesis with ARTP resulted inreduced workload,effectively increased screening flux,and accelerated screening process.Desired target strain was obtained fleetly.This experiment provided a foundation for study of strain with high yield of surfactin.

γ-聚谷氨酸产生菌枯草芽孢杆菌(Bacillus subtilis) HD 11经常压室温等离子体诱变处理,以不产生脂肽作为筛选标准之一,获得1株高产菌株HNCL1266,其γ-聚谷氨酸摇瓶发酵产量为26 g/L,较菌株HD11提高了30％,且遗传稳定.在5L发酵罐上,添加0.2 g/L的泡敌可有效抑制泡沫的产生,γ-聚谷氨酸产量达到30 g/L.

小麦纹枯病是由禾谷丝核菌引起的土传病害,生物防治具有重要的理论意义和应用前景。从发病小麦根系土壤中分离筛选出1株高效的拮抗菌株,电镜扫描结果显示菌体呈短杆状,大小一般在(1.7～2.1)μm×(0.5～0.8)μm。进一步通过生理生化鉴定及16S rRNA基因序列分析,确定为枯草芽孢杆菌。采用红外光谱分析将抗菌活性成分初步鉴定为酯肽类物质。

Twenty strains with petroleum as single carbon source were isolated from petroleum contaminated soil in Puyang petroleum field.The dominant bacteria KF-2 was identified as Alcaligenes xylosoxidans through morphological,physiological and biochemical identification,as well as 16S rRNA sequence analysis.With single factor and orthogonal experiment,the effects of carrier type and amount,pH,ratio of material to water,culture temperature,culture time and dry temperature on living bacteria count of bacterial agent from KF-2 were studied on 150 mm culture dish.The optimum conditions of bacterial agent preparation were wheat bran 10 g,pH 9,ratio of material to water 1∶3.6,cultivation at 25 ℃ for 3 d and dried at 30 ℃.The maximum living bacteria count of KF-2 agent attained 7.24×1010 CFU/g.

To alleviate dissolved oxygen limitation in inosine fermentation process,a new-style air distributor was used to establish Taylor vortex column in 50 m3 gas-liquid agitating fermentor.The results showed that Taylor vortex column could reduce the coalescence effect between bubbles and size of bubbles,improved oxygen supply capability of fermentor.The maximum value of OUR in the prophase of the fermentation attained 100 mol·m-3·h-1 increasing from 85 mol·m-3·h-1,the yield of inosine attained 36 g/L increasing from 32 g/L.Furthermore,the result in power saving test drew a conclusion of 54% electricity saving by reducing agitating electric current.