甜高粱与粒用高粱茎秆生长过程中糖及其代谢相关酶活性的比较

以粒用高粱和甜高粱为材料,对甜高粱与粒用高梁不同时期茎秆的可溶性糖含量、蔗糖含量、果糖含量及SS、SPS酶活力进行比较,结果表明:茎秆中的可溶性糖含量、果糖含量在完熟期甜高粱高于粒用高粱,乳熟期茎秆中蔗糖含量甜高粱高于粒用高粱;两种高粱类型的SPS酶活力变化趋势基本相似,从乳熟期到完熟期粒用高粱茎秆中的SPS酶活力明显增高,SS酶活力在粒用高粱茎秆中随生育期呈上升趋势,甜高粱茎秆中SS酶活力到乳熟期达到最大,明显高于粒用高粱.对糖含量与其相关代谢酶活力的相关性分析表明:甜高粱茎秆中利用SPS酶合成蔗糖的效率要高于粒用高粱;两种类型高粱的SS酶活力与其茎秆中的果糖含量存在明显差异,SS的作用模式不同.     

粒细胞-巨噬细胞集落刺激因子与生长抑素融合表达基因疫苗的免疫对断奶仔猪某些代谢物浓度的影响

选择40头断奶的长×大二元杂交仔猪,随机分为4组,每组10头,公母各半,其中1组为对照组,2～4组分别口服以减毒沙门氏菌为载体的基因疫苗pcS/2SS、pGM-CSF/SS和pGM-CSF pcS/2SS,研究这些基因疫苗对断奶仔猪血浆代谢物浓度的影响.结果显示,对照组和pcS/2SS基因疫苗免疫组仔猪血浆葡萄糖浓度没有明显变化,pGM-CSF pcS/2SS免疫组呈现下降的趋势,融合表达质粒pGM-CSF/SS的免疫则可提高血浆葡萄糖的浓度;血浆游离脂肪酸的分泌水平各免疫组间无明显差异;血浆尿素氮的浓度pGM-CSF/SS免疫组有上升的趋势,在第2周、4周和6周血浆尿素氮的浓度高于其它3个组(P＞0.05),pcS/2SS免疫组则随免疫时间的延长而逐渐下降.对照组和pGM-CSF pcS/2SS免疫组一直保持比较平稳的态势.结果表明,GM-CSF提高了SS基因疫苗的免疫效果,pGM-CSF/SS要优于pGM-CSF pcS/2SS共同免疫.     

猕猴桃细菌性溃疡病菌T3SS关键效应蛋白基因致病功能

[目的]由丁香假单胞菌猕猴桃致病变种(Pseudomonas syringae pv.actinidiae,Psa)引起的猕猴桃细菌性溃疡病是全球猕猴桃产业最具毁灭性的病害.病原细菌主要通过Ⅲ型分泌系统(typeⅢsecretion system,T3SS)将多种效应蛋白(T3SS effector,T3SE)注入寄主...     

SrfC of Pseudomonas cichorii JBC1 affects its attachment to the host surface and host tissue infection

Plant pathogenic Pseudomonas species produce effectors, toxins and cyclic lipopeptides to infect various host plants. Despite many studies aiming to understand the underlying mechanisms of virulence in Pseudomonas spp., the function of genes in the srf gene cluster including srfC, which was formerly known as HopL1, remains undetermined. To investigate the roles of srf genes in the virulence of the bacterial pathogen, each srfA, srfB, srfC and srfD gene from the srf cluster of Pseudomonas cichorii JBC1 was knocked out. When tomato seedlings were infected with the knockout mutants by flood inoculation, disease incidence was suppressed only in srfC-defective mutants (∆srfC) compared to wildtype. Interestingly, when the ∆srfC strain was inoculated directly into the apoplast of tomato leaves by vacuum infiltration, disease developed similar to that of the wildtype. In addition, the ∆srfC strain showed defective swarming motility and biofilm formation, and the attachment of ∆srfC cells on the leaf surface was significantly reduced compared to wildtype. Furthermore, droplets of the ∆srfC culture supernatant did not spread on a hydrophobic surface, unlike the wildtype. The results indicate that the SrfC protein plays important roles in swarming motility, biofilm formation and attachment/colonization on host surfaces; thus, it is beneficial for the pathogen's dispersion and entry into host tissues and consequently contributes to disease development. This study elucidates for the first time the functional role of srfC in P. cichorii virulence. The results will broaden understanding of plant and bacterial pathogen interactions.     

开花期喷施表油菜素内酯对豫麦49 蔗糖代谢和产量的影响

以豫麦49为供试材料,在大田试验条件下研究了开花期喷施表油菜素内酯（epi—BR）对小麦蔗糖代谢及其关键酶活性和产量的影响。结果表明,开花期喷施epi—BR提高了旗叶的叶绿素含量,增加了磷酸蔗糖合成酶（SPS）活性和蔗糖含量;增强了籽粒中蔗糖合成酶（SS）活性,加速了籽粒中蔗糖的降解,进而增加了穗粒数、粒重和产量。在本试验条件下,开花期喷施10．0μg／L的epi—BR的处理小区产量比对照提高了8．6％。     

Changes in sugar content and relative enzyme activity in grape berry in response to root restriction

Root restriction often depresses photosynthetic capacity and reduces shoot growth, but the photosynthate accumulation in fruit under restriction is higher than in control fruit. However, changes in metabolism responsible for these differences are unclear. To identify the metabolic mechanism by which root restriction affects sugar accumulation in fruit of ‘Kyoho’ grape (Vitis vinifera × V. labruscana), sugar metabolism and related enzyme activities in grape berries produced with and without root restriction were compared. Total sugar content of fruit produced under root restriction was higher than that of control fruit. Acid invertase (AI, EC 3.2.1.26) activity, which increases with berry development, was significantly higher in root-restricted berries than in control berries. Neutral invertase (NI, EC 3.2.1.26) activity showed a similar trend to AI, but the amount of NI activity was lower than AI in both treatments. Sucrose phosphate synthase (SPS, EC 2.4.1.14) and sucrose synthase (SS, EC 2.4.1.13) activity changed slightly with berry development, and there was no significant difference in SS and SPS activity between root restriction and control treatments. Therefore, AI appears to be the key enzyme induced by root restriction that explains the higher sugar content found in grape berry produced under root restriction.     

水稻淀粉合成相关基因SSⅠ、SSⅢ-1和PUL对稻米品质的影响

可溶性淀粉合成酶基因(soluble starch synthaseⅠgene,SSⅠ)和SSⅢ-1以及极限糊精酶基因(pullulanase,PUL)是淀粉合成过程中参与支链淀粉合成的关键基因。为了研究SSⅠ、SSⅢ-1和PUL对稻米(Oryza sativa L.)品质的影响,本研究以颗粒结合淀粉合成酶基因(granule bound starch synthas,Wx)与SSⅡ-3均相同的籼型(indica)光温敏核不育系广占63S与潜力三系恢复系CG173R为亲本构建的B1C1F9株系作为供试材料,分析回交重组自交系(backcross inbred lines,BILs)各株系的蒸煮食味品质。结果表明,双亲仅在焦磷酸化酶基因大亚基基因(ADP-glucose pyrophos-phorylase large subunit ADPG,AGPlar)、分支酶3基因(starch branching enzymeⅢgene,SBE3)、PUL、SSⅠ和SSⅢ-1基因位点存在差异;SSⅠ、SSⅢ-1和PUL基因在B1C1F9株系中分离对蒸煮品质指标具有显著影响。SSⅢ-1基因在后代分离过程中,不同基因型之间碱消值(alkaline spreading value,ASV)、峰值粘度(peak viscosity,PKV)、崩解值(breakdown value,BDV)和峰值时间(peak time,Pe T)4个指标具有显著性差异;PUL基因在后代分离过程中,不同基因型之间,胶稠度(gel consistency,GC)和回复值(consistence value,CSV)具有显著性差异(P<0.05);在SSⅢ-1和SSⅠ基因同时分离的株系中,裂区试验分析表明,SSⅢ-1和SSⅠ基因的互作效应对糊化温度(gelatinization temperature,GT)的效应达极显著水平(P<0.01),对表观直链淀粉含量(apparent amylose content,AAC)、GC、PKV和ASV的效应达显著水平(P<0.05)。说明SSⅢ-1和PUL基因对稻米蒸煮食味品质的部分理化指标有显著影响,且SSⅢ-1和SSⅠ基因之间存在显著的互作效应。在相同Wx和SSⅡ-3基因基因背景下,研究稻米淀粉合成途径效应较小的基因对稻米食味品质的影响,对改良稻米蒸煮食味品质和加快稻米品质育种研究具有重要意义。     

荧光假单胞菌SS101对苹果再植病害的生防效果

为明确荧光假单胞菌SS101对苹果再植病害的生防效果,采用平板对峙法和孢子萌发法研究了SS101菌株对9株来自不同苹果产区病原菌的抑制作用以及对盆栽海棠实生苗、海棠大苗和苹果树生长的影响,并测定了连续处理4年苹果树的产量。结果显示,SS101菌株对9株病原菌的菌丝生长抑制率为39.39%~72.00%,对孢子萌发抑制率为19.86%~51.77%;经SS101菌株处理后,海棠实生苗叶绿素含量、株高和鲜重均显著高于再植土处理,分别提高13.38%、19.39%和48.26%;经SS101菌株处理后,海棠大苗定植9个月后,茎粗净增长量为2.97 mm,增长率为214.05%,而再植土处理仅为114.02%;连续处理4年的苹果树平均单株产量比再植土处理提高139.46%,且消除了再植病害症状。研究表明,SS101菌株对苹果再植病害病原菌具有显著抑制作用,在田间对再植病害具有良好的防控效果。     

Modification of physicochemical properties and in vitro digestibility of wheat flour through superheated steam processing

Native and moistened wheat flours (moisture contents were 13.5 and 27.0%, respectively) were treated with superheated steam (SS) at different temperatures (140 and 170 °C) and times (1, 2 and 4 min). Their physicochemical and digestive properties were analyzed. For native flour, SS treatment altered the starch molecular structure and behavior slightly. While for moistened flour, crystalline degree, gelatinization enthalpy, amylose leaching (AML) and falling number significantly decreased, but thermal transition temperatures increased with the rise of treating severity. Clumping of starch granules, aggregation of proteins and formation of amylose-lipid complexes occurred in both native and moistened flours. Broader pasting temperature ranges and higher viscosities were found on SS-modified flours. Additionally, SS treatment on moistened flours increased resistant and slowly digestible starch contents. In general, SS treatment induced changes in starch molecular structure and reactions among flour components leading to more stable structures, thus affecting their pasting behavior, thermal properties and in vitro digestion.     

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.