为探明神经酰胺的皮肤屏障保护功能和抑制细胞增殖促进分化凋亡间的关系，本课题在研究两类化学物（有机溶剂、洗涤剂）和神经酰胺对皮肤角朊细胞增殖、分化和凋亡影响的基础上进一步探索神经酰胺对皮肤角朊细胞周期中不同时相蛋白质、基因的调控作用，已阐明两类化学物对神经酰胺双重作用影响的理论意义和实用价值。

Research background: Schistosomiasis has been epidemic and endemic in tropic and.subtropic areas around the world, with more than 200 million people infected. The.diagnosis of schistosomiasis and the detection of schistomes has so far been based on.morphological methods. Since there are 6 species of schistosomes regularly affecting.human beings and more than 10 species of animal schistosomes, the detection.methods based on morphological characteristics of schistosomes are neither sensitive.nor specific. Therefore, it is necessary to look for new techniques for diagnosis of.schistosomiasis. It has been well recognized that repetitive DNA sequences are.important characteristics and components of genomes of eukaryotes. Generally,.repetitive DNA sequences keep replicating in the genomes but do not express any.products, having themselves more rapidly evolve than other DNA components in the.genomes. Thus, different species or different strains of a specie of biological organism.may be more likely to have different presentations of repetitive DNA sequences and.thus may be more easily to be differentiated. According to this perspective, we have.suspected that we will be able to develop a new diagnostic method if we can.determine and identify a family of repetitive DNA sequences in the genome of.schistosome japonicum..Main study: We have determined the existence of repetitive DNA sequences in the.genome of schistosomes including schistosome japonicum, through partically.construting and screening the genomic library as well as polymerase chain reaction.method. A new detection method for schistosomes was also developed..Main findings: 1. We have identified the presence of repetitive DNA sequences in.genomes of schistosomes including schistosome japonicum. 2. We sequenced the.repetitive DNA sequences in the genome of schistosome haematobium and.schistosoma japonicum. 3. Partially constructed a Sau3A-digested genomic library of.Schistosoma japonicum and identified a new, tandemly arranged and highly repeated.128bp DNA sequence in the genome of Schistosome japonicum by screening the.genomic library. We will reported this newly identified DNA sequence to GeneBank.and will publish our results to the world upon further characterization of this sequence..4. Developed a new, simple and sensitive PCR method for detection of schistosoma.japonicum. 5. Developed a new, simple and user-friendly DNA extraction method for.snails. 6. Determined the infection status of snails collected in the field sites endemic.with schistosomes and demonstrated the applicability of our new snail DNA.extraction method and simplicity and sensitivity of schistosome detection method..Scientific implications: 1. We firstly, in the world, identified the 128bp, tandemly.arranged and highly repeated DNA sequence in the genome of Schistosoma.japonicum. 2. We developed a new, sensitive PCR method for detection of.schistosoma japonicum. A wide application may be foreseeable given further.modifications on our method. 3. The scientific ideas and strategies of our project may.4serve as useful references for our counterparts in studying other parasites.