16S rDNA克隆文库解析AO-MBR系统中细菌种群多样性

采用分子生物学手段16S rDNA克隆文库方法对缺氧/好氧膜生物反应器(AO-MBR)的好氧池与缺氧池中细菌进行了多样性研究.实验结果表明,好氧池污泥样品的克隆文库包括9个类群,其中变形菌(Proteobacteria)和拟杆菌(Bacteroidetes)在文库中所占比例最大,分别为37.04％和14.81％;其次是酸杆菌(Acidobacteria)、未培养菌(uncultured bacterium)、绿菌(Chlorobi)和未培养的绿弯菌(uncultured Chloroflexi bacterium)、浮霉状菌(Planctomycetes),分别为11.11％、11.11％、7.41％、7.41％和5.56％;硝化螺旋菌(Nitrospirae)和裸藻门(Euglenozoa)所占比例相对较小,均为1.85％.缺氧池样品克隆文库包括10个类群,其中变形菌(Proteobacteria)、拟杆菌(Bacteroidetes)和未培养菌(uncultured bacterium)在文库中所占比例最大,分别为27.91％、13.95％和12.79％;其次是浮霉状菌(Planctomycetes)、酸杆菌(Acidobacteria)和绿弯菌(Chloroflexi),在文库中所占比例分别为9.3％、9.3％和9.3％;硝化螺旋菌(Nitrospirae)、裸藻门(Euglenozoa)、芽单胞菌(Gemmatimonadetes)和放线菌(Actinobacteria)所占比例相对较少,分别为6.98％、8.14％、1.16％和1.16％.两池细菌的主要类群相似,但菌属及比例有所差异,变形菌是系统中的主要脱氮菌属.     

图书馆书库清点方法初探

图书馆藏书大多存在实物与财产登记不符的状况，如情况较为严重则会影响到图书馆流通、采访等项工作的开展，因此适时进行书库清点具有重要意义。本文以中国环境管理干部学院图书馆的清点为实例，初步探讨了将条码作为清点切入点的书库清点工作的方法、步骤和注意事项。     

Biological Activity in a Heavily Organohalogen-Contaminated River Sediment (8 pp)

Background, Aims and Scope Sediments of the Spittelwasser creek are highly polluted with organic compounds and heavy metals due to the discharge of untreated waste waters from the industrial region of Bitterfeld-Wolfen, Germany over the course of more than one century. However, relatively few data have been published about the chloroorganic contamination of the sediment. This paper reports on the content of different (chloro)organic compounds with special emphasis on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), and chlorobenzenes. Existing concepts for the remediation of Spittelwasser sediment include the investigation of natural attenuation processes, which largely depend on the presence of an intact microbial food web. In order to gain more insight in terms of biological activity, we analyzed the capacity of sediment microflora to degrade organic matter by measuring the activities of extracellular hydrolytic enzymes involved in the biogeochemical cycling of carbon, nitrogen, phosphorus and sulfur. Furthermore, the detection of physiologically active bacteria in the sediment, particularly of those known for their capability to reductively dehalogenate organochlorine compounds, illustrates the potential for intrinsic bioremediation processes. Methods PCDD/F and chlorobenzenes were analyzed by gas chromatography(GC)/mass spectrometry and GC/flame ionization detection, respectively. The activities of hydrolytic enzymes were determined from freshly sampled sediment layers using 4-methylumbelliferyl (MUF) or 7-amino-4-methylcoumarin-conjugated model compounds and kinetic fluorescence measurements. Physiologically active bacteria from different sediment layers were microscopically visualized by fluorescence in situ hybridization (FISH). Specific bacteria were identified by 16S rRNA gene amplification and sequencing. Results and Discussion The PCDD/F congener profile was dominated by dibenzofurans. In addition, the presence of specific tetra and pentachlorinated dibenzofurans supported the assumption that extensive magnesium production was one possible source for the high contamination. A range of other chloroorganic compounds, including several isomers of chlorobenzenes, hexachlorocyclohexane and 1,1,1-trichloro-2,2-bis (p-chloro-phenyl)ethane (DDT), was present in the sediment. Activities of extracellular hydrolytic enzymes showed a strong decrease in those sediment layers that were characterized by high contents of absorbable organic halogen (AOX), indicating disturbed organic matter decay. Interestingly, an abnormal increase of cellulolytic enzyme activities below the organochlorine-rich layers was observed, possibly caused by residual cellulose from discharges of sulfite pulping wastes. FISH revealed physiologically active bacteria in most sediment layers from the surface down to the depth of about 60 cm, including members of Desulfitobacterium (D.) and Sulfurospirillum. The presence of D. dehalogenans was confirmed by its partial 16S rRNA gene sequence. Conclusions Results of chemical sediment analyses demonstrated high loads of organochlorine compounds, particularly of PCDD/F. Several years after stopping the waste water discharge to Spittelwasser creek, this sediment remains a main source for pollution of the downstream river system by way of the ongoing mobilization of sediment during high floods. As indicated by our enzyme activity measurements, the decomposition potential for organic matter is low in organochlorine-rich sediment layers. In contrast, the comparably higher enzyme activities in less organochlorine-polluted sediment layers as well as the presence of physiologically active bacteria suggest a considerable potential for natural attenuation. Recommendations and Perspectives From our data we strongly recommend to explore the degradative capacity of sediment microorganisms and the limits for in situ activity towards specific sediment pollutants in more detail. This will give a sound basis for the integration of bioremediation approaches into general concepts to reduce the risk that permanently radiates from this highly contaminated sediment. Submission Editor: Dr. Henner Hollert (Henner.Hollert@urz.uniheidelberg.de)     

面向作物病害识别的高光谱波谱库设计与开发

自20世纪70年代以来,国内外波谱数据库发展迅速,但都存在着针对性不强的缺陷,不能满足我国现阶段遥感应用的需要。该文通过以小麦条锈病为案例的高光谱波谱库的设计与开发,实现了波谱查询、影像管理、用户管理、数据管理、反演模型等功能,可供其它面向病害识别的高光谱波谱库的建立参考。     

An investigation of methods for enriching trophoblast from maternal blood

Trophoblast deportation is known to occur in normal human pregnancy, but it is not yet clear whether these cells routinely enter the maternal peripheral circulation and are available as a source of fetal DNA for non-invasive prenatal diagnosis of genetic disorders. To resolve this issue requires an efficient method of enriching trophoblast from maternal blood combined with a means to confirm its identity. Five different techniques were tested on ten retroplacental blood samples to determine the most sensitive and operator-efficient method. Lysis of red cells alone gave the best recovery of trophoblast but had to be discounted, together with Ficoll density gradient centrifugation, due to the very low purity and the excessive time required. Fluorescence-activated cell sorting (FACS) of pre-enriched trophoblast resulted in the lowest recovery rate (8 per cent) despite a 3250-fold enrichment and a very high purity. Immunomagnetic beads (Dynabeads) coated with anti-CD 16 antibody proved to be the best method for the subsequent immunocytochemical characterization of deported trophoblast. However, IO beads coated with anti-CD45 antibody may be more useful for isolating trophoblast for prenatal diagnosis due to the high purity, enrichment (32-fold), and recovery rate (78 per cent) obtained with this method.     

Prenatal investigation of a 45,X/46,X,r(?) karyotype in amniocytes using fluorescence in situ hybridization with an X-centromeric probe

The karyotype of cultured amniotic fluid cells obtained on the indication of advanced maternal age was shown to be a mosaic 45,X/46,X,r(?). The small size and banding pattern made it difficult to determine whether the ring was derived from and X or a Y chromosome, or even from an autosome. By using an X-centromeric probe and fluorescence in situ hybridization (FISH), we demonstrated the ring to have an X centromere. Thus, a more complete genetic counselling was possible. This confirms the usefulness of FISH in identifying and characterizing this and other chromosome rearrangements in prenatal diagnosis.     

低浓度渣油-水系乳化液的抑尘性能现场试验研究

本文介绍了作者用渣油－水系乳化液做路面抑尘剂在某矿露天坑３种不同类型路面进行的大规模工业性试验。现场测定结果表明：这种路面抑尘剂可以获得比较理想的防尘效果，长期使用该乳化液可取得显著的综合经济效益。     

Hybridization between wheat (Triticum aestivum) and the wild species Aegilops geniculata and A. biuncialis under experimental field conditions

Hybridization between Aegilops geniculata, A. biuncialis and bread wheat Triticum aestivum has been evaluated during two seasons under simulated field conditions to estimate the field hybridization rate under Central Spain conditions. The mean frequencies of hybridization between A. biuncialis and A. geniculata with wheat were 0.34% and 0.31%, respectively. Data from 10 hybrid plants for each combination showed that hybrids can be partially fertile by backcrossing with wheat parent, with percent averages of 3.17 grains/spikelets for A. biuncialis × wheat hybrids and 2.87 grains/spikelets for A. geniculata × wheat hybrids. Self-pollination, although at very low rates, was also possible in hybrids. The potential risks associated with natural hybridization in the context of transgenic wheat cultivation are discussed.     

Distribution characteristics of ammonia-oxidizing bacteria in the Typha latifolia constructed wetlands using fluorescent in situ hybridization(FISH)

A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria（AOB） quantity and the relation with oxidation-reduction potential（ORP） in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.     

Characterization of marker chromosomes by microdissection and fluorescence in situ hybridization

We characterized by microdissection and fluorescence in situ hybridization (FISH) two marker chromosomes: (1) a de novo, acrocentric marker chromosome detected in 88 per cent of the amniotic fluid cells of one of two physically and developmentally normal twins; and (2) a metacentric marker chromosome present in a phenotypically normal female. Analysis of FISH probes developed from the marker chromosomes indicated that the marker chromosomes in cases 1 and 2 were del(14)(q11) and a derivative chromosome from a Robertsonian translocation, respectively. Microdissection in combination with FISH may prove to be a valuable technique in determining the chromosomal origin of de novo marker chromosomes and unbalanced structural rearrangements detected during prenatal diagnosis.