季节性雪被对高寒草甸土壤微生物量碳、氮动态的影响

[目的]探索季节性雪被对高寒草甸土壤微生物量碳、氮动态的影响。[方法]根据自然雪被分布的差异,在青藏高原东南缘的高寒草甸生态系统中设置3条雪梯度样带（深雪、中雪和浅雪）,于2008年秋冬过渡期监测各样带中土壤温度和含水量,并研究不同雪梯度下土壤微生物量碳、氮的动态变化。[结果]月均土温、每月日最高土温均值、每月日最低土温均值都分别与雪厚度呈显著二次函数关系。雪厚度和土壤温差对土壤含水量具有显著影响。在秋冬过渡期末,深雪梯度中土壤微生物量碳先显著升高又显著降低;浅雪梯度中,土壤微生物量氮在稳定的浅雪被（约10cm）形成后显著增加。雪被下土壤微生物量碳、氮含量都分别与土壤温度呈显著的三次函数关系。[结论]季节性雪被对土壤温度和土壤含水量有显著影响,也引起高寒草甸土壤微生物量碳、氮动态的明显差异。     

猪卵母细胞不同孤雌激活方法的研究

通过对不同电激活参数的摸索,电激活和化学激活联合的研究,以确定适合于猪卵母细胞孤雌激活的最佳方案。结果表明,体外成熟猪卵母细胞在电场时程60μs,1次直流脉冲的条件下,电场强度1.6kV/cm时其卵裂率(88.68%)和桑葚胚率(81.13%)较其他各组高。在电场强度为1.6 kV/cm,1次直流脉冲的条件下,脉冲时程20μs时,卵母细胞卵裂率仅为75.38%,桑葚胚率为64.62%;40和80μs时,卵裂率分别是84.62%和77.17%;100μs时,卵母细胞的卵裂率和桑葚胚率都明显下降。在电场强度为1.6kV/cm,电场时程为60μs的条件下,2次电脉冲激活卵母细胞的卵裂率(87.50%)、桑葚胚率(81.25%)和1次电脉冲的卵裂率(88.68%)、桑葚胚率(80.13%)之间无显著性差异(P﹥0.05),但两者均显著高于3次电脉冲的卵裂率(72.50%)和桑葚胚率(70.27%)。成熟卵母细胞经电刺激(ES)后,分别用CB(7.5μg/mL)、CHX(10μg/mL)、6-DMAP(2 mmol/L)、CB(7.5μg/mL)+CHX(10μg/mL)、CB(7.5μg/mL)+6-DMAP(2 mmol/L)各自处理4 h,ES+CB+CHX和ES+CB+6-DMAP组卵裂率显著高于其他3组,但其桑葚胚率差异不显著。结果显示,电场强度为1.6 kV/cm,电场时程60μs,1次脉冲的电刺激对体外成熟的猪卵母细胞(IVM)孤雌激活效果最好;1次或2次电脉冲就足以激活猪卵母细胞,过高脉冲对细胞反而有伤害作用;电激活和化学激活联合应用可提高猪卵母细胞的卵裂率。     

黄酮类化合物抑制小胶质细胞活化的构效关系研究

探讨系列黄酮类化合物抑制脂多糖(LPS)诱导的原代大鼠小胶质细胞激活的构效关系。采用MTT分析法检测细胞存活率;Griess法测定LPS激活的小胶质细胞NO释放的变化。在0.3～30μM浓度范围内,8种黄酮类化合物与LPS联合应用对小胶质细胞存活率无显著影响;黄酮、白杨素、芹菜配基、汉黄芩素、四羟黄酮5种黄酮类化合物可显著抑制LPS激活的小胶质细胞NO产生,而二羟黄酮类3种化合物(二羟黄酮、柚皮素、儿茶素)对细胞NO无显著抑制作用。黄酮类化合物母核结构中C-23,双键可能对抑制小胶质细胞激活很重要,其抑制作用的强弱取决于分子的取代类型。     

不同尿素含量培养条件下复合菌系GF-20菌种组成及功能差异

为明确复合菌系GF-20在不同尿素含量培养条件下的菌种组成及功能差异,提高复合菌系的应用性及适用性,以复合菌系GF-20为研究对象,采用16S rDNA扩增子测序技术研究其菌种组成及代谢通路丰度。结果表明:不同尿素含量培养条件下复合菌系菌种组成较为相似,主要由纤维素弧菌属、黄杆菌属、纤维单胞菌属、假单胞菌属和无色杆菌属等功能菌组成,但其丰度存在显著差异。在N2条件下,复合菌系的alpha多样性指数较其他处理高,其物种组成更加丰富和多样。不同处理复合菌均注释到较多的碳水化合物代谢和氨基酸代谢;对N1(硫酸铵氮源)和N6(尿素氮源)处理间碳水化合物代谢通路注释丰度差异比较发现,戊糖和葡萄糖醛酸酯的相互转化、磷酸戊糖途径、半乳糖代谢、果糖和甘露糖代谢、氨基糖和核苷酸糖代谢、淀粉和蔗糖代谢和抗坏血酸盐和藻酸盐代谢等代谢通路丰度呈N1显著高于N6。综上所述,复合菌系GF-20在不同尿素含量培养条件下具有良好的菌种组成及功能稳定性,可适用于原位秸秆还田实践,促进北方高寒地区玉米秸秆降解速率。     

微生物菌剂在番茄上的肥效试验研究

番茄连续多年重茬种植后,土壤易发生土传病害,地力水平降低,直接影响了番茄的正常生长,降低了番茄的产量和品质。通过使用微生物菌剂可以减少土传病害,改良土壤,增加土壤中有益微生物的多样性,提高番茄产量和品质。本试验设计四个处理:施用微生物菌剂灭活微生物菌剂、常规施肥、空白对照,研究微生物菌剂在番茄上的肥效试验,结果发现,微生物菌剂能显著改善番茄生物学性状,使果实横纵径、单果重增大;增强对枯萎病、青枯病的抗性;提高番茄的产量和经济效益,比常规施肥增产6.45%,比空白对照增产44.67%。     

基于化学型时间温度指示器的鲜食葡萄品质监测

为探明化学型时间温度指示器(TTI)应用于鲜食葡萄采后品质变化的监测效果,对不同温度贮藏条件下鲜食葡萄理化指标,以及不同激活时间(2和4s)的TTI总色差变化进行研究。结果表明:1)鲜食葡萄的硬度变化符合一级反应动力学方程,反应活化能为63.54 kJ/mol;2)激活时间为2和4s时TTI的反应活化能分别为73.96和69.14 kJ/mol;3)激活时间为4s时,TTI与葡萄的反应活化能差值<20 kJ/mol,且TTI预测的鲜食葡萄品质变化值与实测值误差(＜15%)较小。TTI对鲜食葡萄的品质变化的监测效果良好,该类型时间温度指示器能够有效监测葡萄品质变化。     

Improvement of the traditional method of ogiri production and identification of the micro-organisms associated with the fermentation process

Fermented products were developed from different proportions of melon (Citrullus vulgaris schrad) and groundnut (Arachis hypogea) seeds after a 96 hour fermentation period. Proximate analysis, carried out on both fermented and unfermented samples, indicated that only the total carbohydrate content was appreciably reduced by the fermentation process. Micro-organisms responsible for fermentation were identified by gram staining and lactophenol staining, as bacteria and fungi. Identified bacteria were of the Bacillus and Acinetobacter species while the fungi were yeasts, rhizopus and mucor. Samples containing 50–100% melon showed a decrease in pH with increasing fermentation period. Bacteria were largely responsible in samples containing up to 75% groundnuts. Sensory analysis of dried fermented products after fortification with salt, ascorbic acid and flour indicated that they were acceptable.     

中华乌塘鳢精子的生物学特性及其超低温保存

对中华乌塘鳢精子激活的生理生态学进行了研究,探讨了中华乌塘鳢精子超低温保存方法,中华乌塘鳢精子激活的适宜盐度为５－１５;其精子的激活不仅与激活溶溶盐度有关,而且与激活溶液的离子成份有关,激活溶液中Ｋ＾＋的存在一定程度上对精子的活动有抑帛和;中华乌塘鳢精子对ＰＨ的适应性强,在ＰＨ５．５－９．５范围内,激活率均在７０９％以上,尤以中性及弱酸性条件下的激活率最高,在ＰＨ６．０时精子活力最好。使用筛选出的     

Photosynthetic suspended-growth systems in aquaculture

Standardized evaluation and rating of biofilters for aquaculture should be assessed in the context of the economic efficiency of ecological services (waste assimilation, nutrient recycling, and internal food production) provided by earthen ponds, and the availability and cost of land, water, and electrical energy resources required to support particular classes of production systems. In photosynthetic suspended-growth systems, water quality control is achieved by a combination of natural and mechanical processes. Natural processes include photosynthesis of oxygen, algal nutrient uptake, coupled nitrification–denitrification, and organic matter oxidation; mechanical processes include aeration and water circulation. Ammonia is controlled by a combination of phytoplankton uptake, nitrification, and immobilization by bacteria. Unlike biofilters for recirculating aquaculture systems, unit processes are combined and are an integral part of the culture unit. The important design and operational considerations for photosynthetic suspended-growth systems include temperature effects, aeration and mixing, quantity and quality of loaded organic matter, and fish water quality tolerance limits. The principle advantages of photosynthetic suspended-growth systems are lower capital costs relative to other recirculating aquaculture systems and increased control over stock management relative to conventional static ponds. The main disadvantage is the relatively low degree of control over water quality and phytoplankton density, metabolism, and community composition relative to other recirculating aquaculture systems. Examples of photosynthetic suspended-growth systems include semi-intensive ponds, intensively aerated outdoor lined ponds, combined intensive–extensive ponds, partitioned aquaculture systems, greenwater tanks, greenwater tanks with solids removal, and greenwater recirculating aquaculture systems.     

复合微生物制剂在日本鳗鲡土池精养中的应用

本研究开展了对日本鳗鲡(Anguilla japonica) 精养殖土池,定期泼洒施用一种复合微生物制剂（Freshplus净水剂）的对比试验,定期监测了处理组和对照组池塘的水温、pH、溶氧、氨氮、亚硝酸盐氮、硝酸盐氮、COD、碱度等水质指标,并分析对比了鳗鱼养殖效果。结果表明：Freshplus净水剂的施用能显著降低鳗鱼土池水体氨氮浓度60.5% (p＜0.05)、显著提高鳗鱼生长速度33.0% (p＜0.05),降低饲料系数9.6% (p＜0.1)。