Development and evaluation of specific PCR primers targeting the ribosomal DNA-internal transcribed spacer(ITS)region of peritrich ciliates in environmental samples

Peritrich ciliates are highly diverse and can be important bacterial grazers in aquatic ecosystems. Morphological identifi cations of peritrich species and assemblages in the environment are time-consuming and expertise-demanding. In this study, two peritrich-specifi c PCR primers were newly designed to amplify a fragment including the internal transcribed spacer(ITS) region of ribosomal rDNA from environmental samples. The primers showed high specifi city in silico, and in tests with peritrich isolates and environmental DNA. Application of these primers in clone library construction and sequencing yielded exclusively sequences of peritrichs for water and sediment samples. We also found the ITS1, ITS2, ITS, D1 region of 28 S rDNA, and ITS+D1 region co-varied with, and generally more variable than, the V9 region of 18 S rDNA in peritrichs. The newly designed specifi c primers thus provide additional tools to study the molecular diversity, community composition, and phylogeography of these ecologically important protists in dif ferent systems.

Annual pattern of zooplankton communities and their environmental response in a subtropical maritime channel system in the northern Bay of Bengal, Bangladesh

Zooplankton plays an important role in aquatic food webs by fluxing of energy from primary producer to subsequent trophic levels in the food chain. The annual pattern of zooplankton communities and potential environmental drivers were studied in the Kohelia channel, Bangladesh from summer 2014 to spring 2015.Samples were collected using net at a depth of 1 m. A total of 32 species belonged to 18 orders, 27 families and 15 taxonomic groups were identified. Of these species, 22 distributed in all four seasons of which 8 were dominant and highly contributing to the total communities. Species number peaked in summer next to winter and fall in spring while maximum abundance was in summer and minimum in spring. Multivariate analyses showed that there was a clear annual pattern in the zooplankton communities. Species diversity and evenness peaked in spring but fall in autumn while the high value of species richness was found in winter. Biological-environmental best matching(BIO-ENV) analyses conformed that community pattern of zooplankton was mainly driven by transparency salinity, and temperature individually or combined with water nutrients. These results demonstrate that annual pattern of the zooplankton community shaped by channel environmental factors in subtropical channel ecosystems, thus might be used for community-based subtropical coastal water bioassessment.

Investigating factors driving phytoplankton growth and grazing loss rates in waters around Peninsular Malaysia

In tropical waters where temperatures are relatively stable,we investigated whether the relationship between phytoplankton growth and grazing loss rate across diff erent habitats around Peninsular Malaysia can be attributed to its eutrophication states.We measured phytoplankton growth(μ)and grazing loss(g)rates in waters off Bachok Marine Research Station(BMRS),located northeast of Peninsular Malaysia.Chlorophyll-a(chl-a)concentration ranged from 2.90 to 15.78μg/L and was dominated by nanoand micro-phytoplankton(>2μm in size).Using the Landry and Hassett dilution method,μat BMRS ranged from 1.02 to 1.58/d whereas g varied from 0.07 to 0.88/d.Grazing accounted for 35%of the primary production at BMRS.A systematic review of available data in waters around Peninsular Malaysia,revealed howμfl uctuated over a wide range(0.01–1.80/d)and correlated with chl a distribution(R 2=0.181,P<0.001).However,the relationship was only signifi cant at<9μg/L chl a for mesotrophic waters and<16μg/L chl a for eutrophic waters.In contrast,g ranged from 0.00 to 1.01/d,and correlated withμat all locations.The g/μslope ranged from 19%to 84%,and was generally similar for waters around Peninsular Malaysia.However,all the g/μslopes had a positive y-intercept except for BMRS,and this seemed to suggest the availability of alternative prey supporting grazing at the other stations.

Enhancement of biogas potential of primary sludge by co-digestion with cow manure and brewery sludge

Anaerobic digestion(AD)has long been used to treat different types of organic wastes especially in the developed world.However,organic wastes are still more often considered as a waste instead of a resource in the developing world,which contributes to environmental pollution arising from their disposal.This study has been conducted at Bugolobi Sewage Treatment Plant(BSTP),where two organic wastes,cow manure and brewery sludge were co-digested with primary sludge in different proportions.This study was done in lab-scale reactors at mesophilic temperature and sludge retention time of 20 d.The main objective was to evaluate the biodegradability of primary sludge generated at BSTP,Kampala,Uganda and enhance its ability of biogas production.When the brewery sludge was added to primary STP sludge at all proportions,the biogas production rate increased by a factor of 3.This was significantly(p<0.001)higher than observed gas yield(337±18)mL/(L·d))in the control treatment containing(only STP sludge).Co-digesting STP sludge with cow manure did not show different results compared to the control treatment.In conclusion,Bugolobi STP sludge is poorly anaerobically degradable with low biogas production but co-digestion with brewery sludge enhanced the biogas production rate,while co-digestion with cow manure was not beneficial.

Simulation of long-term nutrient removal in a full-scale closed-loop bioreactor for sewage treatment： an example of Bayesian inference

在这，学习，氮的表演和在一个照原尺寸的靠近环的生物反应器(氧化阴沟) 的磷移动系统用 ASM2d 模型被模仿。描述这进程二年的平淡的数据为刻度和确认被编。克服 identifiability 问题，经典贝叶斯的推理途径为参数评价被利用。校准的模型能描述滋养的移动的长期的趋势和过程表演的短期的变化，证明贝叶斯的方法是为激活的污泥模型的参数评价的一个可靠、有用的工具。由积累有机体(PAO ) 的 polyphosphate 的缺氧的磷酸盐举起贡献了 71.2% 全部的息肉存储，它揭示在限制的氧下面的磷移动过程调节的从的优势。它被发现 58.7% 缺氧的息肉存储，由在反应堆的 PAO 的 denitrification 在充气分隔空间被完成，暗示 PAO 缺氧的活动被低溶解的氧显著地刺激() 在由于氧，坡度由刷子通风装置引起了的这分隔空间的水平。

Effectiveness of plant growth-promoting rhizobacterium Pantoea sp. BRM17 in enhancing canola growth on phosphogypsum-amended soil

Dear Editor,Phosphogypsum(PG)is the main by-product generated during phosphoric acid production from mineral rocks.It contains mainly calcium sulfate dehydrate(CaSO4:2H2O),phosphate,fuoride,heavy metals,and radionuclides(Elloumi et al.,2015).Around 170×10^6 t PG is produced annually worldwide,although PG management is an environ-mental concern in several countries.

Colonization features of marine biofilm-dwelling protozoa in Chinese coastal waters of the Yellow Sea

Colonization features of biofilm-dwelling protozoa,especially ciliates,are routinely used as a useful tool for marine bioassessment.In this review,we summarize some of these features to develop an optimal sampling strategy for using biofilmdwelling protozoa as bioindicators of marine water quality.We focus on the utility of:(1)diversity in dices to analyze the colonizahon features of biofilm-dwelling protozoa for monitoring marine water quality;(2)MacArthur-Wilson and logistic equation models to determine spatio-temporal variations in colonization dynamics;and(3)homogeneity in taxonomic breadth of biofilm-dwelling protozoa during the process of colonization.The main findings are that:(1)the colonization dynamics of biofilm-dwelling protozoa are similar at depths of 1-5 m in spring and autumn;(2)temporal variability was well fitted to the MacArthur-Wilson and logistic models(P<0.05);and(3)species composition reached an equilibrium after a colonization period of 10-14 days in spring and autumn,but this took less time in the summer and more time in the winter.Ellipse-plotting tests demonstrated spatial variability in homogeneity in taxonomic structure of the ciiiate communities at different depths in the water column,with high levels at 1 m and 2 m and lower levels at 3.5 m and 5 m.Thus,the findings of this review suggest that the colonization dynamics of biofilin-dwelling protozoa may be influenced by different depths and seasons in coastal waters and 1-2 m in spring and autumn may be optimal sampling strategy for bioassessment on large spatial/temporal scales in marine ecosystems.

The differentiation of iron-reducing bacterial community and iron-reduction activity between riverine and marine sediments in the Yellow River estuary

Rivers are the primary contributors of iron and other elements to the global oceans.Iron-reducing bacteria play an important biogeochemical role in coupling the iron and carbon redox cycles.However,the extent of changes in community structures and iron-reduction activities of iron-reducing bacteria in riverine and coastal marine sediments remains unclear.This study presents information on the spatial patterns and relative abundance of iron-reducing bacteria in sediments of the Yellow River estuary and the adjacent Bohai Sea.High-throughput sequencing of bacterial 16S rRNA found that the highest relative abundances and diversities were from the estuary(Yellow River-Bohai Sea mixing zone).Pseudomonas,Thiobacillus,Geobacter,Rhodoferax,and Clostridium were the most abundant putative iron-reducing bacteria genera in the sediments of the Yellow River.Vibrio,Shewanella,and Thiobacillus were the most abundant in the sediments of the Bohai Sea.The putative iron-reducing bacterial community was positively correlated with the concentrations of total nitrogen and ammonium in coastal marine sediments,and was significantly correlated with the concentration of nitrate in river sediments.The riverine sediments,with a more diverse iron-reducing bacterial community,exhibited increased activity of Fe(III)reduction in enrichment cultures.The estuary-wide high abundance of putative iron-reducing bacteria suggests that the effect of river-sea interaction on bacterial distribution patterns is high.The results of this study will help the understanding of the biogeochemical cycling of iron in riverine and coastal marine environments.

铁氧化菌耐砷机制及其砷污染修复应用的研究进展

砷污染作为全球性环境问题已经引起了人们的高度重视。无机砷化合物可与铁氢氧化物络合通过共沉淀作用去除。因此,利用具有砷耐性的铁氧化菌氧化环境中的铁元素去除砷化合物具有潜在的应用前景。目前已有利用铁氧化菌去除环境中砷污染物的报道。用于砷污染修复的铁氧化菌必须有一定的砷耐性才能在含砷环境中行使功能。微生物是否具有砷耐性往往取决于基因,并且不同的菌株具有不同的生理特征,适宜不同砷污染环境的修复。本文通过对8株代表性的铁氧化菌砷耐性基因的总结,阐述其耐砷机制、研究概况及应用前景,以期为铁氧化菌用于除砷新技术的开发提供参考。

微生物与矿物建筑材料的相互作用(英文)

综合介绍了比利时根特大学Magnel实验室与其他合作单位关于微生物与建筑材料（混凝土和石材）之间相互作用的研究概况。第一个研究课题是生物硫酸腐蚀，主要研究混凝土下水道系统和储肥设施的侵蚀。整个过程可用纯化学或微生物侵蚀实验来模拟。利用化学硫酸实验来模拟侵蚀过程的缺点是忽视了混凝土本身的杀菌效果。微生物实验结果表明使用具有高度中和能力的材料可限制生物腐蚀的发生。因此，生物硫酸侵蚀模型中不但需要考虑耐久性（如孔隙率），也需要把混凝土碱性列为参数之一。第二个研究课题是细菌在胶结固化和混凝土自修复中的应用。细菌诱导产生的碳酸钙用于水泥基材料和石灰石的表面防护。研究表明：沉积在表面的生物碳酸钙可有效降低混凝土吸水率、碳化和氯离子侵蚀；还能提高混凝土抗冻融性能。多孔石灰石表面固化深度可达到30mm甚至更多，固结区的强度可增加300％。与此同时，微生物碳酸钙也被应用于混凝土裂缝自修复。细菌先被固载于硅藻土或微胶囊内，然后加入到混凝土中与其一起搅拌。结果显示：加有硅藻土固载的细菌的砂浆试块上0．15～O．17mitt宽的裂缝可在40d内被细菌诱导产生的碳酸钙完全修复；而加有微胶囊固载的细菌的试块上1rnm宽的裂缝可以在3周内自修复完毕。微生物在混凝土中的另一个应用是创造绿色生态混凝土墙壁。这种混凝土墙壁经过特殊设计获得特定的微观结构和生物兼容性，从而可充当生物生长的基体。为了适于生物生长，使用低pH值的磷酸镁水泥混凝土和碳化水泥混凝土，并对其他影响生物兼容性的因素如混凝土孔隙率、表面粗糙度等进行了优化研究。