Isolating cDNA clones from rice induced by Magnaporthe grisea using PCR based differential screening method

The differential hybridization technique hasbeen widely used to identify genes that are dif-ferentially expressed.However,this approachhas several drawbacks.First,the screeningprocedures are rather labor-intensive and time-consuming.Second,the amount of phageDNAs transferred onto the two filters may notbe equivalent,which leads to an inaccurate se-lection of a positive clone.Third,isolation ofphage DNA is slow and cumbersome.Here,aPCR based differential screening method that

IDENTIFICATION OF A NEW HUMAN nm23 GENE,nm23-H3b

Nm23 is a kind of effective tumor metastasis suppressor genes which included two types in human:nm23-H1 and nm23-H2. Amino acid identity between nm23-H1 and nm23-H2 was 88%.In this study,using a pair of primers to flank the part of coding sequence of nm 23,the 5'-translated sequence was amplified by polymerase chain reaction (PCR) from human normal liver genomic DNA.A 375-base pairs clone was charactertzed,which designated pnm23-H3b.The nm23-H3b nucleotide sequence between 40 bp and 70 bp is different from nm23-H1 and nm23-H2,and other sequences have 86%and 90%identical to nm23-H1 and nm23-H2,respectively.Southern blot containing BglⅡ-digested human liver genomic DNA hybridized to the entire nm23-H3b DNA and showed three bands at 10.5,7.9 and 4.0 Kb.These data demonstrate that the third human nm23 exists possibly.Therefore,nm23 may be considered a family of closely related genes.

高效厌氧氨氧化颗粒污泥脱氮特征及EPS分层特性

考察了处理低氨氮废水的厌氧氨氧化颗粒污泥的脱氮特征、分层EPS组分及三维荧光光谱特性。结果表明,厌氧氨氧化颗粒污泥表现出高效的厌氧氨氧化活性,对NH+4-N和NO-2-N的平均降解速率分别为0.14和0.15 g/(g VSS·d),去除率分别为80.1%和97.0%;对TN的去除率为65.8%;该过程伴随N_2O的产生和短时积累,峰值浓度为0.92 mg/L,仅占TN转化率的2.52%;另外,p H值能指示厌氧氨氧化反应的终点。对分层EPS组分的分析可知,蛋白质为所有EPS层的主要成分,达226.9 mg/g VSS,占EPS总量的58.9%;绝大部分EPS为TB-EPS,占EPS总量的77.1%。三维荧光光谱显示蛋白质主要为酪氨酸和色氨酸,两者在TB-EPS中的荧光强度分别为165.5和46.1 AU/(mg C·L)。该研究结果为今后厌氧氨氧化污泥颗粒化的研究提供了理论依据。