伴大豆球蛋白胃蛋白酶水解肽对小鼠免疫功能及肠道内环境的影响

90只清洁级昆明系小鼠,随机分为5组,预饲基础日粮一周后,各组分别灌胃：生理盐水（对照组,CK）、伴大豆球蛋白液（Ⅰ）、伴大豆球蛋白胃蛋白酶水解液（Ⅱ）、伴大豆球蛋白胃蛋白酶水解液提纯B组分（Ⅲ）、伴大豆球蛋白盐酸水解液（Ⅳ）,除对照组外,各处理组灌胃液体总含氮量相等,实验期21d。结果显示：与对照组相比,第3周Ⅱ组和Ⅲ组每只小鼠日均采食量较对照组显著下降,分别降低8．75％（P〈0．05）和9．28％（P〈0．05）;Ⅲ组小鼠胸腺相对质量极显著下降,降低了10．40％（P〈0．01）,肠黏膜sIgA水平提高45．49％（P〈0．01）,大肠食糜中6-磷酸果糖酮糖酶（F6PPK）活性极显著提高（P〈0．01）,pH值下降了1．80％（P〈0．05）,肠球菌数显著下降（P〈0．05）。实验结果表明水解肽作为腔内信号分子可能与肠道内相关因素有着多层次调控关系,共同促进宿主的健康。     

NMF菌群腐熟牛粪对植物病害及土壤微生物的影响

采用盆栽试验研究了NMF菌群腐熟牛粪对植物病害以及土壤微生物的影响。结果表明,NMF菌群腐熟牛粪能明显降低小麦纹枯病和番茄灰霉病的发病率,对水稻恶苗病的抑制效果不明显。另外,腐熟牛粪可以促进土壤中细菌和放线菌的生长,抑制土壤中真菌的生长。     

杭州规模化猪场两种通风模式下育肥舍内环境因子的比较分析

【目的】研究两种通风模式下杭州地区规模化猪场舍内环境参数及其分布规律,筛选出适合本地区推广的通风模式。【方法】选取杭州地区具有代表性的横向通风和纵向通风两种通风模式下育肥舍为研究对象,开展了早、中、晚3个不同时间点,进风口、舍中央和排风口3个不同位置的热环境参数、有害气体浓度的监测,持续监测1周。分析不同时间点和舍内不同位置对热环境参数(温度、相对湿度、风速)以及有害气体(氨气(NH₃)和硫化氢(H₂S))浓度的影响,并对两种模式下的热环境参数及有害气体浓度进行比较分析;采用空气沉淀法收集舍内环境中的细菌,并对细菌进行培养及统计分析,比较两种模式下育肥舍中细菌数量差异。【结果】两种通风模式下育肥舍相对湿度均低于国家标准,位置和各时间点对相对湿度影响不大,其中纵向通风舍内的相对湿度显著高于横向通风模式(P<0.05)。两种通风模式舍内平均温度没有显著性差异(P>0.05),舍内中午温度显著高于早、晚(P<0.05),位置对纵向通风舍内温度影响较大。纵向通风舍内平均风速为(1.09±0.42)m/s,符合国家标准且极显著高于横向...     

Perspectives of Using L-Tryptophan for Improving Productivity of Agricultural Crops: A Review

Plant growth regulators are biologically active signaling molecules that regulate a number of plant physiological processes. Auxin (indole-3-acetic acid) is an important plant growth regulator and is synthesized within plant tissues through L-tryptophan (L-TRP)-dependent and -independent pathways. It has been found that plants respond to exogenously applied L-TRP due to insufficient endogenous auxin biosynthesis. The exogenous application of L-TRP is highly significant for normal plant growth and development. L-tryptophan is applied through foliar spray, seed priming, and soil application. Soil-applied L-TRP is either directly taken up by plants or metabolized to auxin by soil microbiota and then absorbed by plant roots. Similarly, foliar spray and seed priming with L-TRP stimulates auxin synthesis within plants and improves the growth and productivity of agricultural crops. Furthermore, L-TRP contains approximately 14% nitrogen (N) in its composition, which is released upon its metabolism within a plant or in the rhizosphere and plays a role in enhancing crop productivity. This review deals with assessing crop responses under the exogenous application of L-TRP in normal and stressed environments, mode of action of L-TRP, advantages of using L-TRP over other auxin precursors, and role of the simultaneous use of L-TRP and auxin-producing microbes in improving the productivity of agricultural crops. To the best of our knowledge, this is the first review reporting the importance of the use of L-TRP in agriculture.     

Genetically engineering better fungal biopesticides

Microbial insect pathogens offer an alternative means of pest control with the potential to wean us off our heavy reliance on chemical pesticides. Insect pathogenic fungi play an important natural role in controlling disease vectors and agricultural pests. Most commercial products employ Ascomycetes in the genera Metarhizium and Beauveria. However, their utilization has been limited by inconsistent field results as a consequence of sensitivity to abiotic stresses and naturally low virulence. Other naturally occurring biocontrol agents also face these hurdles to successful application, but the availability of complete genomes and recombinant DNA technologies have facilitated design of multiple fungal pathogens with enhanced virulence and stress resistance. Many natural and synthetic genes have been inserted into entomopathogen genomes. Some of the biggest gains in virulence have been obtained using genes encoding neurotoxic peptides, peptides that manipulate host physiology and proteases and chitinases that degrade the insect cuticle. Prokaryotes, particularly extremophiles, are useful sources of genes for improving entomopathogen resistance to ultraviolet (UV) radiation. These biological insecticides are environmentally friendly and cost‐effective insect pest control options. © 2017 Society of Chemical Industry     

Liquid Chromatography-Mass Spectrometry-Based Rapid Secondary-Metabolite Profiling of Marine Pseudoalteromonas sp. M2

The ocean is a rich resource of flora, fauna, and food. A wild-type bacterial strain showing confluent growth on marine agar with antibacterial activity was isolated from marine water, identified using 16S rDNA sequence analysis as Pseudoalteromonas sp., and designated as strain M2. This strain was found to produce various secondary metabolites including quinolone alkaloids. Using high-resolution mass spectrometry (MS) and nuclear magnetic resonance (NMR) analysis, we identified nine secondary metabolites of 4-hydroxy-2-alkylquinoline (pseudane-III, IV, V, VI, VII, VIII, IX, X, and XI). Additionally, this strain produced two novel, closely related compounds, 2-isopentylqunoline-4-one and 2-(2,3-dimetylbutyl)qunoline-4-(1H)-one, which have not been previously reported from marine bacteria. From the metabolites produced by Pseudoalteromonas sp. M2, 2-(2,3-dimethylbutyl)quinolin-4-one, pseudane-VI, and pseudane-VII inhibited melanin synthesis in Melan-A cells by 23.0%, 28.2%, and 42.7%, respectively, wherein pseudane-VII showed the highest inhibition at 8 µg/mL. The results of this study suggest that liquid chromatography (LC)-MS/MS-based metabolite screening effectively improves the efficiency of novel metabolite discovery. Additionally, these compounds are promising candidates for further bioactivity development.     

绿僵菌与8种红火蚁防控常用农药相容性

研究了茚虫威、多杀菌素、苯氧威、氟虫腈、硼酸、烯虫酯、阿维菌素和高效氯氰菊酯等防控红火蚁的常用农药在田间推荐剂量及亚致死剂量下对黄绿绿僵菌Metarhizium flavoviride SM076和金龟子绿僵菌M. anisopliae M09萌发、生长及产孢的影响。结果表明,0.1 mg/mL茚虫威、0.1 mg/mL多杀菌素和0.5 mg/mL烯虫酯浓度下,对黄绿绿僵菌SM076萌发、生长及产孢等没有影响。0.5 mg/mL茚虫威、0.1 mg/mL阿维菌素、0.01 mg/mL苯氧威、0.5 mg/mL烯虫酯和0.05 mg/mL氟虫腈对金龟子绿僵菌M09的萌发、菌丝生长和产孢量均无影响。因此在田间应用这两种虫生真菌时,可以考虑与上述农药结合使用。     

分子生物学技术在环境微生物检测和污染治理中的应用

综述了聚合酶链式反应技术(PCR)、生物芯片技术、酶联免疫吸附技术(ELISA)、生物传感器4种现代分子生物学技术的基本原理及其在环境微生物检测和治理中的应用,以期为现代分子生物学技术在环境微生物检测和治理中的进一步研究提供参考。     

昆虫病原线虫与黑色粘板配合使用对韭菜迟眼蕈蚊的防治

为探索昆虫病原线虫与色板配合使用对韭菜迟眼蕈蚊的综合防治技术,采用培养皿滤纸法比较7品系昆虫病原线虫对韭蛆3龄幼虫的致病力,盆栽法研究斯氏线虫属3品系线虫的保苗和防治效果;并通过温室和田间试验比较10种颜色粘板和3个粘板高度对迟眼蕈蚊成虫的诱集效果,研究线虫与黑色粘板配合使用对韭菜迟眼蕈蚊的防治效果。结果表明:SF-SN品系线虫对韭菜迟眼蕈蚊3龄幼虫致病力最高,LD50为60.0条/头,施用线虫剂量为200、400条/头时,其保苗和防治效果高低依次为SF-SN、All、NC116,其中施用SF-SN品系5 d,保苗效果达62.74%,防治效果达60.26%;黑色粘板诱集效果极显著高于其它色板,且下部(色板下缘离地面1 cm处)诱集成虫量最多,与中部(15 cm)、上部(30 cm)之间差异极显著。研究表明,SF-SN品系线虫主要用于防治幼虫,黑色粘板主要诱杀成虫,二者配合使用防治效果可达97.60%,能够极大地降低虫口基数。     

不同类型白刺沙丘土壤理化性状与微生物相关性研究

利用民勤荒漠绿洲过渡带不同类型白刺沙丘的土壤微生物、土壤理化性状及二者之间的相关性进行研究,旨在探讨白刺沙丘的成土过程,为绿洲生态建设提供基础数据,结果表明,1)固定、半固定和流动沙丘粘粒、粉粒、细砂粒、粗砂粒含量差异较大;土壤养分含量与土壤粘粒、粉粒、细砂粒等细沙物质含量呈正相关性,与粗砂粒含量呈负相关性,表现为土壤养分含量随土壤颗粒的增大,相关性减弱。2)土壤微生物类群数量在半固定沙丘明显高于固定沙丘和流动沙丘。3)过渡带土壤均处于偏碱性状态,有机质、全氮、全磷、全钾、水解氮、速效钾、速效磷和CaCO₃含量随沙丘发育年代的增加逐渐增加。4)不同年代沙丘中土壤微生物和土壤理化因子均具较好的相关性,尤其是细菌和放线菌与pH值呈显著的负相关关系,土壤有机质含量与三大菌群数量都表现出显著的正相关关系。