瘤胃微生物不同种群对小麦秸体外降解的研究

实验设置5个处理组,研究瘤胃微生物不同种群对小麦秸的降解作用。结果发现：瘤胃细菌在整体上对纤维素性物质的降解力强;瘤胃真菌也能降解部分粗纤维类物质,但作用较小;瘤胃细菌和真菌在降解中具有一定的互作关系。体外干物质降解率、总挥发性脂肪酸、总气体产量、总甲烷气体产量、羧甲基纤维素酶活力可以作为评定瘤胃微生物降解活力的指标。     

Diversity of cultivable endophytic bacteria associated with halophytes in Xinjiang of China and their plant beneficial traits

Endophytic bacteria from halophytes have a wide range of application prospects in various fields, such as plant growth-promoting, biocontrol activity and stress resistance. The current study aimed to identify cultivable endophytic bacteria associated with halophytes grown in the salt-affected soil in Xinjiang Uygur Autonomous Region, China and to evaluate their plant beneficial traits and enzyme-producing activity. Endophytic bacteria were isolated from Reaumuria soongorica (PalL Maxim.), Artemisia carvifolia (Buch.-Ham. ex Roxb. Hort. Beng.), Peganum harmala L. and Suaeda dendroides (C. A. Mey. Moq.) by using the cultural-dependent method. Then we classified these bacteria based on the difference between their sequences of 16S rRNA (16S ribosomal RNA) gene. Results showed that the isolated bacteria from R. soongorica belonged to the genera Brucella, Bacillus and Variovorax. The bacteria from A. carvifolia belonged to the genera Micromonospora and Brucella. The bacteria from P. harmala belonged to the genera Paramesorhizobium, Bacillus and Peribacillus. The bacteria from S. dendroides belonged to the genus Bacillus. Notably, the genus Bacillus was detected in the three above plants, indicating that Bacillus is a common taxon of endophytic bacteria in halophytes. And, our results found that about 37.50% of the tested strains showed strong protease-producing activity, 6.25% of the tested strains showed strong cellulase-producing activity and 12.50% of the tested strains showed moderate lipase-producing activity. Besides, all isolated strains were positive for IAA (3-Indoleacetic acid) production, 31.25% of isolated strains exhibited a moderate phosphate solubilization activity and 50.00% of isolated strains exhibited a weak siderophore production activity. Our findings suggest that halophytes are valuable resources for identifying microbes with the ability to increase host plant growth and health in salt-affected soils.     

Besnoitia cysts in the adrenal gland of a cow

Summary

An unusual finding of Besnoitia besnoiti was discovered during histopathological examination of the adrenal gland of a cow brought to slaughter.     

高职农业微生物学课程教学改革研究

高职院校的农业微生物学教学对实践能力的培养要求较高,而目前实际教学中往往存在理论知识占比过大,实践课程课时不足,学生能力和素质未能得到有效提高等问题。笔者在结合近年课程教学实践的基础上,从调整课程内容、提高教学水平、改进教学方法、创新课程考核方式4个维度,介绍了农业微生物学课程教学改革的经验。     

Chemical and Microbiological Soil Characteristics under Conventional and Organic Coffee Production Systems

The objective of this study was to evaluate the effect of Conilon coffee (Coffea canephora) cultivated under conventional and organic management systems on the chemical and microbiological characteristics of the soil, as compared to an Atlantic forest. Chemical soil properties, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial activity (MA), and metabolic quotient (qCO2) were determined at depths of 0–10 cm and 10–20 cm in two seasons (summer and winter). Although microbiological attributes varied according to the season and soil depth, MBC provided 54.15% of relative contribution to distinguish the treatments, followed by MBN and MA. Results indicate that the cultivation of coffee under organic management is more sustainable than under conventional system. Carbon from microbial biomass was the most important soil microbiological attribute in the clustering of the different management methods. Atlantic forest soil followed by organic coffee cultivation soil showed the best soil-quality indices.     

Rapid and Cost-Effective Method for Soil Carbon Mineralization in Static Laboratory Incubations

We evaluated a modified approach for carbon (C) mineralization using a single-cell infrared gas analyzer (IRGA). Objectives were to (i) determine if IRGA, gas chromatography (GC), and alkali absorption of carbon dioxide (CO₂) in sodium hydroxide (NaOH) have similar results over 21 days; (ii) determine how these methods correlate; (iii) estimate the limit of quantitation (LOQ); (iv) compare throughput times; and (v) estimate the concentrations of CO₂ and oxygen (O₂) that suppress respiration. IRGA did not differ from the GC and NaOH results over 21 days. Coefficients of determination (R²) for IRGA, GC, and NaOH had values of 0.92 or more. IRGA and GC had the lowest LOQ (115 and 90 ppm CO₂), with the greatest LOQ (600 ppm CO₂) found with NaOH. IRGA had the fastest sample throughput (150 h^–1), followed by 17 and 10 h^–1 for GC and NaOH, respectively. Average suppression concentrations were 5.3% for O₂ and 10.5% for CO₂.     

微量热法在土壤微生物研究中的应用进展

一切生命过程都伴随着热效应。微量热法可对这些热效应进行精确的跟踪,并表征其过程。微量热法已广泛应用于医药、生化等研究领域,但在土壤微生物研究中却鲜有应用。本文简要介绍微量热法的原理和实验方法,综述其在土壤微生物研究中的应用现状并展望其应用前景,以期为土壤微生物研究提供新的思路和技术。     

不同清洗剂对鲜切生菜品质及贮藏期间微生物的影响

以鲜切散叶生菜为研究对象,分别研究在4℃贮藏条件下,自来水、次氯酸钠和氧泡泡颗粒3种清洗剂对其生理指标、感官品质和微生物生长情况的影响。结果表明,氧泡泡颗粒处理的鲜切生菜感官评分最高,在贮藏至第8天时,仍可以维持较好的品质,可溶性固形物含量比鲜样降低0.8%,维C含量降低1.09 mg/100 g,还原糖含量降低0.11%,叶绿素含量降低1.443 mg/100 g,在一定程度上延缓了生菜的萎蔫,从而延长其货架期,并且菌落总数小于6 lg(CFU/g),具有食用价值。氧泡泡鲜氧颗粒可用于鲜切散叶生菜的清洗,在抑制微生物生长繁殖的同时可以维持较好的感官品质。     

催化铁-生物耦合处理草甘膦废水生物出水的可行性研究

[目的]针对草甘膦生产过程中排出的废水有机物和有机磷浓度高、可生化性差,传统工艺难以达标的问题,进行催化铁还原技术的可行性研究,为现有处理工艺的改造提供参考。[方法]通过摇瓶试验和SBR持续试验,对催化铁还原技术和微生物处理过程耦合处理现有草甘膦废水生物出水COD和磷的去除效果进行研究。[结果]将催化铁还原技术与微生物处理过程耦合能够提高草甘膦农药废水的COD和TP去除效果;耦合的SBR系统在微氧条件下对原厌氧出水的COD和TP去除率分别稳定在80.0%和50.0%以上,正磷酸盐浓度在20.00 mg/L以下。[结论]催化铁-生物耦合为草甘膦废水的处理和改造提供了一种较好的处理方法。     

引进国外先进技术 促进北京市草莓产业快速发展

为加强日系草莓品种的抗病性,减轻病虫害危害、增加产量,以提高京郊草莓种植水平,北京市农业技术推广站在北京市对外科技交流协会的支持下,先后聘请日本专家对北京市草莓生产进行技术指导。通过技术交流,先后引进了草莓高架基质栽培、营养钵育苗和高架网槽式育苗等新型技术,丰富了北京市草莓栽培模式,提升了草莓种苗的品质,有效地促进了北...