第六届九源奖学金一等奖论文摘要（2）

4、籼稻基因组工作框架图 （发表刊物：Science, Vol. 296(5),79）

We have produced a graft sequence of the rice genome for the most widely cultivated subspecies in China, Oryza sativa L. ssp. indica, by whole-genome shotgun sepuencing. The genome was 466 megabases in size, with an estimated 46,022 to 55,615 genes, Functional coverage in the assembled sequences was 92.0%. About 42.2% of the genome was in exact 20-nucleotide oligomer repeats, and most of the transposons were in the intergenic regions between. Although 80.6% of predicted Atabidopsis thaliama genes had a homolog in rice, onluy 49.4% of predicted ride genes had a homolog in A. thaliana. The large ptopottion of rice genes with no recognizable homologs is due to a gradient in the GC content of rice coding sequences.

5、The general anesthetic pentobarbital slows desensitization and deactivation of the glycine receptor in the rat spinal dorsal horn neurons （发表杂志：J Biol Chem, Vol. 277, 41369-41378）

Although many general acesthetics have been found to produce anesthetic and analgesic effects by augmenting GABAA receptor (GABAAR)function, the role of the glycine receptor (GlyR) in this process is not fully understood at the neuronal level in the spinal cord. We investigated the effects of a barbiturate general anesthetic, pentobarbital(PB), on the glycinergic miniature inhibitory postsynaptic currents(mIPSCs) and the responses to exogenously applied glycine, or taurine, a low affinity GlyR agonist, by using the whole-cell patchclamp technique in the rat spinal dorsal horn neuros isolated using a novel mechanical method. Bath application of 30 μM PB significantly prolonged the decay time constant of the spontaneous glycinergic mIPSC without changing its amplitude and frequency. Coapplication of 0.3μM PB reduced the pead amplitude, affected the macroscopic desensitization and deactivation of the response to externally applied Gly in a concentration-dependent manner. In addition, the recovery of Gly response from desensitization was also proonged by PB. However, PB did not change the desensitization and deactivation kinetics of the taurine-induced response. The GABAAR antagonist bicuculline(10μM) did not affect the effect of PB on the Gly response. Thus, PB ptolonged the sponal glycinergic mIPSCs by slowing desensitization and deactivation of GlyR. Two other structurally different intravenous anesthetics, i.e. prlpofol(10μM) and etomidate (3μM), prolonged the duration of the glycinergic mIPSC in the rat spinal dorsal horm neurons. In conclusion, on GlyR-Cl- channel complexes there may exist action site(s) of intravenous general anesthetics. GlyR and glycinergic neurotransmission may play an important role in the modulation of general acesthesia in the mammalian spinal cord.

作者：吕辉 （中国科技大学生命科学学院攻读硕士学位，师从徐天乐教授，专业特长：受体药理学）。

6、Correlation between a single nucleotide polymorphism in the matrix metalloproteinase-2 promoter and risk of lung cancer （发表杂志：Cancer Research, 2002,Vol. 62, 6430-6433）

Matrix metalloproeinases (MMPs) play an important role in several steps of cancer development. A single nucleotide polymorphism(-1306C→T)in the MMP2 promoter sequence disrupts an Spl site and thus results in strikingly lower promoter activity. Ww wxamined the relationship between this polymorphism and risk for lung cancer in 781 cases and 852age-and sex-matched controls in a Chinese population. We found that the allele frequency of MMP2-1306C was significantly higher among cases than among controls (0.91versus 0.83). Subjects with the CC genotype had an overall 2-fold increased risk for developing lung cancer[adjusted odds ratio (OR)2.08; 95% confidence interva (CI), 1.70-2.79]compared with those with the CT or TT genotype. The elevated risk was observed evenly among different subtypes of this cancer. Stratified analysis indicated an additive interaction between the CC genotype and smoking on the elevated risk. The ORs of lung cancer for the CC genotype, smoking, and both factors combined were 2.38(95% CI 1.64-3.45), 4.26(95%CI 2.57-8.44), and 7.64(95%CI 4.74-12.33), respectively. Furthermore ,when the data were stratified by the pack-years smoked, this joint effect was more evident and stronger in heavy smokers(OR 5.55,95%CI 3.34-9.22). these results demonstrate a significant association between the MMP2-1306C/T polymorphism and risk of developing lung cancer, solely or in a manner of interaction with carcinogen exposure.

作者：于春媛 （中国协和医科大学攻读博士学位，师从林东昕教授，专业特长：肿瘤学）。

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