生活污水人工渠自净过程及原生动物演替

为探讨小城镇生活污水人工渠自净的可行性及原生动物的响应过程,采用传统的生化分析方法并结合最新的基因指纹技术,对哈尔滨双城市居民生活污水水体自净过程中的水质变化以及相应的指示性原生动物的动态演替进行分析.结果表明,化学需氧量(COD)为140 mg/L的生活污水,经由约9 km的人工渠,通过沉降、化学分解、生物代谢等作用,降至40 mg/L以下,碱度逐渐从1000 mg/L下降至250 mg/L,pH从7.3上升至8.0;总磷含量由2.0 mg/L逐渐降低至1.3 mg/L.在整个过程中的原生动物种类较少,主要有草履虫属、四膜虫属和鞭毛虫属.鞭毛虫属一直是优势原生动物,草履虫属和四膜虫属在寡污带出现,最后消失.居民生活污水在人工渠中通过较长的自净流程(≥9 km)达到排放的要求,注入松花江支流拉林河.     

Multiplex PCR–capillary electrophoresis–SSCP used to identify foodborne pathogens

Multiplex PCR–CE–SSCP approach was used to identify foodborne pathogens. 16srRNA system including three target fragments localized at different position of 16srRNA gene and gyrB system including two target fragments at gyrB gene were established. SSCP profile was analyzed in a similar way as RAPD and the identity of each peak was determined by relative position to inner standard. Twenty-five reference bacteria strains representing 2 classes, 12 genus and 19 species were tested. All bacteria could be distinctly determined at genus level by 16srRNA system. GyrB system improved discriminating resolution of some bacterial at species level. Phylogenetic analysis showed that 16srRNA based phylogenetic relationship was consistent with traditional classification of these organisms. Good reproducibility and resolution make multiplex PCR–CE–SSCP protocol a promising approach for fast screening of foodborne pathogens.     

Single nucleotide polymorphisms in the ovine casein genes detected by polymerase chain reaction-single strand conformation polymorphism

Casein genetic polymorphisms are important and well known due to their effects on quantitative traits and technological properties of milk. At the DNA level, polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) allows for the simultaneous typing of several alleles at casein loci, as well as the detection of unknown polymorphisms. Here we describe the usefulness of the PCR-SSCP technique for casein typing in sheep. In particular, three single-nucleotide polymorphisms (SNP) are described at CSN1S1, CSN2, and CSN3, all resulting in amino acid exchanges. At CSN1S1, a transition T-->C was found, resulting in the deduced amino acid exchange Ile186-->Thr186. A transition A-->G resulting in the deduced amino acid exchange Met183-->Val183 was identified at CSN2. The 2 SNP showed a rather high frequency (ranging from 0.12 to 0.26) in 3 Italian breeds (Sarda, Comisana, Sopravissana). Another transition C-->T (Ser104-->Leu104) was found at CSN3 in one heterozygous animal.     

Genetic differentiation between the clam species Ruditapes decussatus (grooved carpet shell) and Venerupis pullastra (pullet carpet shell) by PCR–SSCP analysis

Genetic differentiation of the clam species Ruditapes decussatus (grooved carpet shell) and Venerupis pullastra (pullet carpet shell) has been achieved based on polymerase chain reaction–single‐strand conformation polymorphism (PCR–SSCP) analysis. A short fragment (150 bp) of the α‐actin gene was amplified by PCR. Amplicons were denatured to obtain single‐stranded DNA, electrophoresed on a non‐denaturing polyacrylamide gel and visualised by silver staining for detection of SSCPs. Species‐specific DNA band patterns were obtained for R decussatus and V pullastra, allowing clear differentiation of the two clam species. © 2002 Society of Chemical Industry     

基于低电压载波通信的智能小区设计

智能小区的普及化发展要求智能小区面向低成本、高性能的目标设计。无论从技术方面或者经济方面考虑,采用电力线载波通信是实现小区智能化的最佳方式。文中结合电力线载波扩频通信技术的优点设计了一个新的智能家庭系统。在电力线为通信介质的前提下,探讨了家庭智能网络的一部分应用——小区自动抄表系统。本设计主要的研究对象的侧重点是整个通信系统中的最基本单元。基于扩频载波芯片IntellonSSCP300的小区自动抄表系统是一个相对经济的解决方案。     

High hydrogen production rate in a submerged membrane anaerobic bioreactor

Batch cultivation of an anaerobic consortium fed with glucose as sole carbon source showed a sharp decrease of the hydrogen productivity when volatile fatty acids (VFA) concentration exceeded 12.5 g L^?1. To avoid VFA accumulation, fermentative batch cultures were thereafter carried out with a submerged membrane anaerobic bioreactor to continuously remove hydrogen fermentation co-products, while retaining the biomass. The membrane made it possible to separate the residence times of bacterial biomass and hydraulic part. With this technology, average and maximal productivities reached 0.75 and 2.46 L_H2 L^?1 h^?1, corresponding to an increase of 44 and 51% in comparison to the control, respectively. By removing the VFAs from the cultivation medium, H₂-producing pathways were favored, confirming the metabolic inhibitory effects of co-product accumulation in fermentation medium. Such hydrogen productivity is one of the highest values encountered in the literature. Readily implementable, such technology offers a good opportunity for further developing high rate hydrogen fermentation bioprocesses.     

基于CEBus协议的使用SSCP300的电力线模块分析

对消费电子总线（CEBus）参考模型及与CEBus兼容的芯片SSCP300作了简单介绍,分析了CEBus的通讯协议及其载波波形,同时对使用P300的典型电力线模块也作出了分析。     

Do milking practices influence the bacterial diversity of raw milk?

The link between milk production practices and bacterial diversity of 67 raw milks from dairy farms in the Savoie and Haute-Savoie regions of France was studied by Single Strand Conformation Polymorphism (SSCP) analysis. The milking practices and the cleanliness of different parts of the cow housing were evaluated. The SSCP bacterial profiles allow to classify the 67 milks into three groups: group A was characterised by a majority of Gram-positive non-lactic acid bacteria (Corynebacterineae and Micrococcaceae) and a high level of hygiene in milking practices. The SSCP profiles of groups B and C were close but different from those of group A: they were both dominated by lactic acid bacteria and by a less intensive hygiene practices. The group B milks were characterised by the dominance of Gram-negative bacteria and Lactococcus lactis species while those of group C were dominated by Brevibacterium linens and Leuconostoc mesenteroides. The variation of balance between bacterial populations can be associated with differences in hygienic milking production practices.     

Rapid polymerase chain reaction (PCR)-single-stranded conformational polymorphism (SSCP) screening method for the identification of Aspergillus section Nigri species by the detection of calmodulin nucleotide variations

Single-stranded conformational polymorphism (SSCP) analysis for genetic diversity studies has been widely applied to detect indirectly sequence differences up to a single base in amplified DNA fragments of the same length, representing an alternative to gene sequencing. In this study SSCP analysis was used to detect sequence variations contained in an about 180-bp region of the calmodulin gene in order to identify Aspergillus section Nigri species. The method described shows that fluorescence-based SSCP analysis by capillary electrophoresis is cheaper and faster than direct sequencing, and suitable for computer-assisted analyses allowing discrimination between the Aspergillus species belonging to the Nigri section: A. aculeatus, Aspergillus 'atypic uniseriate', A. brasiliensis, A. carbonarius, A. ellipticus, A. foetidus, A. heteromorphus, A. ibericus, A. japonicus, A. niger, and A. tubingensis.