Transgenic Betula pendula expressing sugar beet chitinase IV forms normal ectomycorrhizae with Paxillus involutus in vitro

Abstract

Mycorrhizal fungi contain chitin in their cell walls and may be influenced by transgenic chitinases. This study examined the ability of a transgenic tree, silver birch (Betula pendula Roth), constitutively expressing the sugar beet chitinase IV gene, to form ectomycorrhizae with Paxillus involutus (Batsch) Fr. Eight transgenic lines showing varying levels of sugar beet chitinase IV expression and the non-transgenic control plants were inoculated by P. involutus in vitro, and the morphology of the mycorrhizae, mycorrhization efficiency and shoot and root fresh weights were studied. All the transgenic birch lines were able to form normal ectomycorrhizae containing distinctive mantles and Hartig nets. The level of sugar beet chitinase IV expression had no significant influence on mycorrhizal colonization. The only significant differences between transgenic and control plants were detected in weight parameters. According to these results, the expression of sugar beet chitinase IV in silver birch is not deleterious to formation of ectomycorrhizae between birch and P. involutus.     

二次加热处理对鲢鱼糜制品品质的影响

通过测定二次加热处理前后鲢鱼糜制品的凝胶强度、持水性、白度、凝胶内部化学作用力、微观结构以及SDS-PAGE各项指标,考察不同二次加热处理条件(70～100℃处理30min和60min)对鲢鱼糜制品品质的影响。结果表明,与对照组相比,随着二次加热处理温度的上升和时间的增加,鱼糜凝胶的凝胶强度、持水性、二硫键以及疏水相互作用均呈现先上升后下降的趋势,尤其是100℃加热60min时其凝胶特性已被完全破坏。微观结构表明,当二次加热处理的温度高于80℃时,鱼糜凝胶内部的三维网状结构均遭到了一定程度的破坏,且随着二次加热处理温度的上升和时间的增加破坏程度加剧,这一结果和上述各指标的变化趋势一致。SDSPAGE电泳图谱结果表明,随着二次加热处理温度的升高,肌球蛋白重链(MHC)条带逐渐下降,当二次加热处理温度达到100℃时,MHC条带几乎消失。     

不同碳基材料对银纳米颗粒的去除效果

本研究合成了稳定分散的纳米银(AgNPs)颗粒,并采用批量试验法研究了水稻壳生物炭(BC)、多壁碳纳米管(CNTs)和石墨烯(GP)3种碳基材料对AgNPs的吸附特性以及环境因素(离子强度、离子种类和电解质pH)对AgNPs吸附的影响。结果表明:AgNPs在碳基材料上的吸附过程符合准二级动力学模型,吸附速率受内扩散和其他过程共同控制,并且在240min内均能达到吸附平衡;与Freundlich模型相比,Langmuir模型能够更好地拟合AgNPs在碳基材料上的等温吸附过程,并且AgNPs在BC、CNTs和GP上的吸附量依次增大,分别达到了69.15、87.78、121.21mg·g~(-1);在试验离子强度(20~100mmol·L~(-1))下,改变Na+强度对碳基材料吸附AgNPs的能力没有显著改变,但Ca2+强度的升高却抑制了GP对AgNPs的吸附,AgNPs在碳基材料上的吸附量随着电解质pH的升高而降低;BC通过络合作用、离子交换作用、沉淀作用和静电作用吸附AgNPs,CNTs和GP主要利用静电作用和范德华力固定溶液中的AgNPs。这些结果有助于了解AgNPs在碳基材料上的吸附行为,并可为更好地评价和管理AgNPs在环境中的风险提供依据。     

Ethylene evolution and sensitivity in cut orchid flowers

The effects of ethylene and the rate of ethylene production were studied in several orchid flowers. Orchid flowers showed a wide range of sensitivity to ethylene; Vanda ‘Miss Joaquim’ was most sensitive, Cattleya, Cymbidium and Paphiopedilum were less sensitive, while Dendrobium and Oncidium were not sensitive. Ethylene production in opened flowers was low, less than 1 nl/flower/h. In Cattleya, a peak in ethylene production was observed at the onset of senescence. Emasculated and/or pollinated flowers of Vanda, Cattleya and Paphiopedilum produced high levels of ethylene; Dendrobium did not react to these treatments in ethylene production.The anionic silver-thiosulfate complex (STS) was partially inhibitory to ethylene production in emasculated Cymbidium flowers, but appeared to stimulate the process in pollinated flowers. It was, however, effective in decreasing anthocyanin synthesis in both emasculated and pollinated Cymbidium flowers. In Cattleya, aminoxyacetic acid (AOA) and STS had no effect on longevity of cut flowers.     

不同种源欧洲白冷杉苗对臭氧熏蒸的反应

用臭氧对6种不同种源的2年生白冷杉苗熏蒸。熏蒸后立即产生反应,表现为光合速率和蒸腾速率降低,呼吸速度加快。熏蒸后3个月,臭氧对苗木的气体交换作用已无明显影响。熏蒸后5个月,苗木的抗冻能力(以LT50表示)分别下降1.1℃(125ppb)和3.2℃(250ppb);高浓度处理的针叶失水速度略有减少。第2年苗木抽芽推迟,生长量降低。     

Survival and growth of silver catfish larvae exposed to different water pH

The objective of this study was to determine the influence ofwater pH (5.5, 6.0, 7.0, 8.0, and 8.5) on survival and growth ofsilver catfsh (Rhamdia quelen) larvae. Larvae were obtained frominduced spawning in November and maintained under controlledconditions of 25 (1) °C using a water re-use system incontinuously aerated 40 L polyethylene tanks (350 larvae/tank).Larvae were fed until satiation six times a day. At days 0, 7, 14,and 21 and after yolk absorption, 10 larvae from each group wererandomly chosen to evaluate length, weight, and specific growthrate (SGR). Length, weight, survival, and biomass at the end of 21days were significantly higher at pH 8.0 and 8.5. As expected,specific growth rate decreased with time. These results suggest that 8.0–8.5 isthe best pH range for survival and growth of the larvae of thisspecies.     

Factors affecting the vase life of fronds of maidenhair fern

Cut fronds of maidenhair fern (Adiantum raddianum), which last only 3 days in DI water, were used as a model system to study factors affecting the vase life of cut greens. Solutions containing 25 mg 1^?1 Ag⁺ increased vase life 5-fold. Other biocides (8-hydroxyquinoline citrate, a quaternary ammonium compound, or 8-hydroxyquinoline citrate + NaOCl) had little effect on vase life, while inhibitors of ethylene (C₂H₄) production (Co²⁺, aminooxyacetic acid) increased vase life. Wound C₂H₄ production by the cut ends of the stipes declined during the first 2 h after cutting. The hypothesis that this C₂H₄ is the cause of the brief vase life of maidenhair fern is discussed.     

应用免疫金探针定位和定量测定稻种中的水稻细菌性条斑病菌

本文首次报道用免疫金染色和免疫金银染色对水稻细菌性条斑病病种的带菌部位及带菌量的研究。结果表明:病原细菌分布于谷壳、籽实皮、胚和胚乳,主要集中在谷壳上。谷壳外表带菌量多于内表面。籽实皮外表面由于受谷壳污染较之内表面的带菌量多。籽实皮内表面、胚和胚乳的带菌量均较少,差异不显著。谷壳、谷壳内表面、籽实皮、胚乳(或胚)的带菌量之比为36:13:9:1。     

小蓟对银黑狐免疫功能及血液生化指标的影响

为更好了解小蓟的药理作用,开发中兽药,采用单因素随机化设计方法,选择健康、体重相近、性别相同的13周龄公银黑狐80只,随机分为5个处理组,每组16只。其中A组为对照组,饲喂基础日粮;B、C、D、E为试验组,在基础日粮中分别添加0.2%、0.4%、0.8%、1.6%的小蓟。结果表明:小蓟的添加提高了平均日采食量、平均日增重增加,降低了料重比;鲜皮重、鲜皮长度有所增加,其中D组(0.8%)效果最好,与对照组相比差异显著(P0.05);增强了机体的免疫功能,使得肝脏和脾脏等器官发育良好;通过调节脂质代谢水平,血清中甘油三酯和总胆固醇的含量降低,白蛋白和球蛋白的比值呈上升趋势,D组(0.8%)效果最好,与对照组相比差异显著(P0.05)。小蓟在银黑狐日粮中的添加比例为0.8%效果最好。