城市污水处理厂微生物气溶胶污染和粒径分布特征

城市污水处理厂微生物气溶胶的污染与控制逐渐成为人们关注的热点问题。为明确城市污水处理厂微生物气溶胶浓度和粒径分布特征,选择鄂尔多斯市某城市污水处理厂的格栅间、配水池、氧化沟、二沉池、污泥脱水间和厂区门口6个功能区为对象,对各功能区产生的异养细菌、真菌和放线菌气溶胶浓度分布、污染特性和微生物粒子粒径分布特性进行研究。结果表明,该污水处理厂不同功能区内异养细菌、真菌和放线菌的浓度分布存在显著性差异,其中二沉池和污泥脱水间产生的异养细菌和放线菌浓度均较高,真菌浓度较高的区域为厂门口和二沉池;根据相关微生物气溶胶污染评价标准,污泥脱水间逸散的异养细菌浓度均达到污染级,二沉池、氧化沟和厂门口逸散的异养细菌浓度达轻微污染级,格栅间和配水池未受污染,而真菌浓度在各个功能区均未受到污染;各功能区产生的异养细菌、真菌和放线菌粒子粒径分布无明显差异,异养细菌、真菌和放线菌粒子粒径分别集中在第1、4级,第3、4级和第1、2、3级,大体上均呈正态分布;各功能区均逸散出一定比例的可以直接吸入人体呼吸道的微生物粒子,可能对人体健康具有一定的潜在风险。研究结果可为城市污水处理厂运行过程中微生物气溶胶的污染控制提供科学依据。     

Effects of different endogenous fungi on the mass loss and nutrient content of leaf litter of Cunninghamia lanceolata北大核心CSCD

To explore the role of endophytic fungi in the decomposition of litter, the endophytic fungi Penicillium sp. strain CG2 (A), Fusarium flavum strain AY13 (B), and Talaromyces strain AJ14 (C) of Cunninghamia lanceolata were added to experimental pots in different forms (mycelium, sterilized fermentation broth, single fungus, and mixed fungi), and a control treatment (CK) was set up (no fungi added). At 10, 30, 60, 90, and 120 days after litter decomposition, a study on the decomposition dynamics of C. lanceolata litter under different treatments was performed. The results showed that the rate of leaf mass loss was the highest in the sterilized fermentation broth treatment A after 120 days, and that there was a significant difference (P < 0.05) between the mycelium treatment AC and the control treatment after 60 days (23.97% higher than the control group). On day 60, the litter carbon content from the mycelium treatment A was significantly different from that of the control (P < 0.05), showing a 16.74% lower value, whereas the litter carbon content of the mycelium treatment B was 21.13% lower than that of the control after 90 days. The nitrogen content of the litters of most mycelium and sterilized fermentation broth treatments was increased compared to that of the control group; there was significant difference (P < 0.05) between the sterilized fermentation broth treatment A and the control (P < 0.05), with a 17.05% higher value than that of the control. Similar to nitrogen, the litter phosphorus content also increased; there was a statistically significant difference between the mycelium treatment A and the control group, with treatment A showing a 46.67% higher value than the control group. The potassium content was 28% lower than that of the control group under the sterilized fermentation broth treatment C, a result that was significantly different from that of the control group (P < 0.05). After treatment for 90 days, the ratio of carbon to nitrogen was the lowest under the treatments with the mycelium A and the mycelium B, with values 25.54% and 25.11% lower than that of the control group, respectively, and a statistically significant difference from that of the control group (P < 0.05). The ratio of carbon to phosphorus was the lowest under the treatment with mycelium A after 60 days, and the result was significantly different from that of the control (P < 0.05), with a 43.05% lower value than the control. Thus, the three endophytic fungi had different effects on the mass loss rate and nutrient content of the litter. The Penicillium sp. strain CG2 (A) had statistically significant effects on the mass loss and nutrient content of leaf litter, which was within the range of fungi fertilizer reference values for the breeding of C. lanceolata. © 2018 Science Press. All rights reserved.     

Effects of two different intercropping systems on arbuscular mycorrhizal fungal colonization and polychlorinated biphenyl (PCB) dissipation北大核心CSCD

Polychlorinated biphenyls (PCBs) are typical organic contaminants in the environment. It is indicated that plants and soil microorganisms have a positive synergistic effect on the remediation of PCB-contaminated soil. To investigate the effect of intercropping on arbuscular mycorrhizal (AM) fungal colonization and PCB remediation, a pot-cultivation experiment with two intercropping treatments, corn (Zea mays L.) / ryegrass (Lolium perenne L.) and corn/alfalfa (Medicago sativa L.), and a corn monoculture was conducted in a greenhouse. All treatments were inoculated with Funneliformis mosseae M47V. Plant biomass, root mycorrhizal colonization rate, concentration of PCBs and their homologs in soil, 16S rDNA gene abundance, and community composition measured by Terminal Restriction Fragment Length Polymorphism (T-RFLP) were determined after harvesting the plants. Intercropping significantly increased the root mycorrhizal colonization rate and plant biomass of corn (P < 0.05), as well as the available N content of the soil. A significant difference of the bacterial community composition was found among different treatments (P < 0.05). Compared with corn monoculture, corn/alfalfa intercropping significantly increased soil bacteria abundance (P < 0.05). The dissipation rates of total PCBs, as well as that of penta-chloro biphenyls were significantly increased in the intercropping treatments, when compared to the corn monoculture treatment. Moreover, corn/ryegrass intercropping has a significantly positive effect on the dissipation of tri-chloro biphenyls. Non-metric multidimensional scaling (NMDS) analysis indicated that the PCBs homologues composition were significantly correlated with the relative abundance of 128 bp and 148 bp T-RFs. Corn intercropping with ryegrass or alfalfa has a positive effect on root mycorrhizal colonization rate and plant biomass of corn. Inoculation of AM fungi in intercropping treatments significantly improved the efficiency of PCB remediation by promoting bacterial abundance and shifting the bacterial community composition. In conclusion, intercropping combined with AM fungi have positive synergistic effects on the remediation of PCB-contaminated soils. © 2018 Science Press. All rights reserved.     

围垦养殖对中国典型滨海湿地土壤真菌多样性及群落结构影响

本研究以我国黄河口碱蓬湿地、九龙江口桐花树湿地、东寨港木榄湿地为研究样地,借助高通量测序技术探究这3个典型滨海湿地围垦养殖前、后土壤真菌多样性及群落结构的变化.结果表明：①不同地域湿地围垦养殖对土壤真菌群落多样性及丰富度影响表现不一致.九龙江口桐花树湿地围垦后,土壤真菌多样性及丰富度有所下降;黄河口碱蓬湿地和东寨港木榄湿地围垦后土壤真菌多样性及丰富度显著增加;②子囊菌门（Ascomycota）在湿地围垦养殖前、后土壤中均为优势真菌门,但其相对丰度在围垦后显著下降;③湿地围垦养殖改变了土壤真菌属水平群落组成,黄河口湿地围垦后,未出现翅孢壳属（Emericellopsis）、毛霉属（Mucor）、枝顶孢属（Acremonium）;九龙江口和东寨港湿地围垦后,青霉属（Penicillium）相对丰度显著下降,并新增了镰刀菌属（Fusarium）,九龙江口湿地围垦后还新增了链格孢属（Alternaria）;④环境因子与湿地土壤真菌相对丰度存在一定程度的相关性,青霉属（Penicillium）与容重呈显著负相关（p<0.05）,与pH呈显著负相关（p<0.01）,与有机碳呈显著正相关（p<0.01）;翅孢壳属（Emericellopsis）与容重和pH呈显著正相关（p<0.05）,与有机碳呈显著负相关（p<0.01）.     

真菌生物滤池净化苯乙烯废气的研究

采用接种Aspergillus candidus和Penicillium frequentans的真菌生物滤池处理苯乙烯废气,考察苯乙烯在生物滤池中的净化效果和物质转化特性。苯乙烯的进气质量浓度为200～800 mg/m3,气体流量分别为0.28,0.38和0.48 m3/h,对应的气体停留时间分别为60,45和35 s。试验结果表明:苯乙烯在真菌生物滤池中有较好的处理效果,最大去除能力达66.78 g/(m3.h),真菌生物滤池中二氧化碳的产生量和苯乙烯去除量呈线性关系。微生物分析结果表明,接种的Aspergillus candidus和Penicillium frequentans在反应器内能够长期保持优势地位。     

丛枝菌根真菌对羊草凋落物降解作用的研究

丛枝菌根真菌（Abuscular mycorrhizal fungi）能够影响植物生长及养分含量,从而影响凋落物的降解。采用根袋的方法研究了接种两种丛枝真菌Glomus mosseae和Glomus claroideum对羊草（Leymus chinensis）地上部及根系凋落物降解的影响。结果表明,随时间的延长,凋落物的重量逐渐减少,凋落物氮、磷含量均表现出先下降后逐渐升高的趋势。接种对地上部凋落物的养分含量及降解速度未产生显著性影响,但显著降低了根系氮磷含量及降解系数。接种Glomus mosseae和Glomus claroideum羊草根系氮、磷含量均显著低于CK;接种与未接种相比羊草根系k值显著降低;根系C：N未接种处理显著低于接种处理。说明丛枝菌根真菌可能间接影响草原生态系统中有机物质的分解和养分释放。     

重金属污染土壤接种丛枝菌根真菌对蚕豆毒性的影响

采用盆栽实验的方法,研究了重金属（包括Cu、Zn、Pb和Cd）复合污染和接种丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）Glomus mosseae对蚕豆（Vicia faba）生长及DNA损伤的影响。结果表明,虽然接种菌根真菌对蚕豆生物量的影响并不显著,但是却显著影响植物对重金属的吸收,接种菌根真菌对蚕豆吸收4种重金属元素的作用有差异。采用单细胞凝胶电泳（single cell gel electrophoresis,SCGE）法研究接种菌根真菌对蚕豆叶片的DNA损伤的影响,与重金属吸收的结果相吻合。结果表明,接种处理可显著增加蚕豆叶片的DNA损伤程度,这与接种处理可提高植物的重金属吸收相一致。     

沙田柚根围AM真菌的生境适宜性和季节变化性

以山地长寿沙田柚成年果树为对象,研究不同生境和季节对丛枝菌根(Arbuscular mycorrhiza,AM)真菌侵染以及根围土壤中AM真菌孢子密度的影响.试验结果表明,不同生境下,菌根侵染率和AM真菌孢子密度都是以梯田最高,坡地次之,洼地最低;在坡地和洼地生境下,生草区均高于清耕区.两块试验地AM真菌的菌丝侵染率均为夏季最高(16.8%±1.9%和16.0%±1.8%),秋季次之,冬季最低;丛枝和泡囊的形成也是夏/秋季较高,春/冬季较低;而根围土壤中AM真菌孢子密度则是秋季最高[(159±19)个/100 g和(167±17)个/100 g],夏季次之,冬季最低.总之,对于长寿沙田柚成年果树,AM真菌的菌根侵染率在夏季梯田最高,根围土壤中的AM真菌孢子密度在秋季梯田最高;在坡地和洼地生境中,生草处理均可显著提高菌根侵染率和AM真菌孢子密度.图4参27     

高寒草原菌根围细菌数量对丛枝菌根真菌物种多样性的影响

基于丛枝菌根真菌(Arbuscular mycorrhizas fungi,AMF)孢子形态学鉴定,研究了藏北高寒草原主要建群植物菌根围细菌数量对AMF物种多样性的影响.结果表明:1)细菌数量1.02×106～2.96×106、3.01×106～6.06×106个/g范围内,Glomus、Acaulospora均为优势属,Scutellospora则均为最常见属;AMF孢子密度、分离频度、相对多度、重要值和种的丰度(SN、SR)均呈Glomus>Acaulospora>Scutellospora属的趋势.2)细菌数量较低时(<3.0×106个/g),AMF各属孢子密度、种的丰度(SR)相对较高,Shannon-Weiner指数、物种均匀度指数亦较高,分别达1.774和0.127.3)不同细菌数量条件下,孢子密度随细菌数量的增加而均呈微弱下降,菌根侵染率、侵染强度、丛枝丰度则均呈不同程度的提高.细菌数量>3.0×106个/g时,菌根侵染率、侵染强度和丛枝丰度随细菌数量增加而提高的趋势尤为明显.4)不同细菌数量条件下,AMF种的构成呈共有种、共有优势种较多(Glomus属均占绝对比重),特有种、稀有种较少,以及不同优势种孢子密度、相对多度和重要值差异均较悬殊的分布特征.图6表3参25     

微生物源槐糖脂对水果致腐真菌的抑制作用

致腐真菌是诱发水果采后病害,造成水果在运输、货架期间和贮藏过程腐败变质的主要原因.从腐烂水果上分离得到17株菌,其中9株为致腐真菌,研究了由拟威克酵母发酵产生的槐糖脂对该9株菌的作用,包括抑菌圈直径、抑菌率和对菌丝蔓延的影响.发现槐糖脂对9株致腐真菌有很好的抑制作用,浓度达到2.0 g L-1时,致腐菌(孢子)抑制率达...