Cyclophilin A is upregulated in small cell lung cancer and activates ERK1/2 signal

Cyclophilin A (CypA), a peptidyl-prolyl cis-trans isomerase (PPIase), was originally identified as the intracellular receptor for cyclosporin A (CsA). Recently, correlations of CypA with tumor pathogenesis have been studied. Here, we studied the expression of CypA and its receptor CD147 in several kinds of lung cancer cells as well as a normal lung cell and found that in H446 cell, a kind of small cell lung cancer cell, the expression are the highest. The exogeneous CypA protein can substantially stimulate H446 cell growth in dependence on its PPIase activity. We also showed that CypA protein can stimulate ERK1/2 signal in dose and time dependent manners and almost has no effect to p38 and JNK signals. Elucidation of the precise role of CypA in these pathways may lead to new targeted therapies for small cell lung cancer.     

大肠杆菌肠毒素的基因融合及其免疫原性的研究

应用重组基因工程技术,将热敏肠毒素Ｂ亚基（ＬＴ－Ｂ）基因与含有部分前体的耐热肠毒素（ｐｒｏ－ＳＴ）基因融合在一起,构建了表达ＬＴ－Ｂ／ｐｒｏ－ＳＴ融合蛋白的重组质粒．该融合蛋白不仅保持结合神经节苷脂（ＧＭ１）的能力,而且具有热敏肠毒素和耐热肠毒素的抗原性．乳鼠实验证明,融合蛋白虽然含有野生耐热肠毒素,但不具耐热肠毒素的生物毒性．腹腔免疫和鼻饲免疫均能激发产生抗ＥＴＥＣ两种肠毒素的抗体．     

Isolation of ScFv antibodies of rP27~(Kip1) from phage display libraries constructed from immunized and non-immunized repertoires

Through mRNA extract, RT and a series of PCR, phage antibody libraries were constructed from rP27~(Kipl)immunized and non-immunized mice. After only one round of selection with rP27~(Kipl), clones from each library were chosen randomly and digested by Taq I and Hinf I. 11 of 64 clones from the immunized animal had consistent restriction pattern, while none of the 64 clones from the non-immunized animal had, except that one had the same fragments pattern as that of the 11 clones. The 12 fragments were expressed in E. coli BL21(DE3)/pET-28b( ) system. ELISA showed that some of the fragments could bind to rP27~(Kipl) specifically. All these results implied that specific antibody can be obtained by genetic engineering without hybridoma or many rounds of growth and panning selection.     

Synthesis of stryphnoside A, a triterpene saponin isolated from the pericarps of Stryphnodendron fissuratum

Stryphnoside A, α-l-rhamnopyranosyl 3β-O-[α-l-arabinopyranosyl-(1→4)-β-d-xylopyranosyl-(1→2)-β-d-glucopyranosyl]-2α-hydroxyolean-12-en-28-oate, has been synthesized in 11 steps in 15% overall yield starting from the naturally abundant oleanolic acid. Condensation of a partially protected glucopyranosyl donor and 2α,3β-dihydroxyolean-12-en-28-oic acid derivative using inverse glycosylation procedure has significantly simplified the target saponin synthesis. Stryphnoside A exhibited weak cytotoxic activities against tumor cells HeLa, A549, and HepG2 with IC₅₀ at mM level.     

Comparative study of QTLs for agronomic traits of riceOriza sativa L.) between salt stress and nonstress environment

Genotype-by-environment interactions (GxE) are commonly observed for quantitative traits. In the present study, a doubled haploid (DH) population and its genetic linkage map were used to comparatively study QTLs in salt stress and nonstress environments. A total of 24 QTLs were detected for five agronomic traits, which were distributed on all the chromosomes except 9 and 11. Under the salt stress, nine (37.5%) QTLs were detected, including one for 1 000-grain weight (GW), two for heading date (HD), one for plant height (PH), two for grains per panicle (GPP), and three for effective tillers (ET), while in the nonstress environment, 17 QTLs (70.8%) were detected, including five for GW, six for HD, three for PH, two for GPP, and one for ET. Two QTLs (8.3%) were consistently detected in both environments. One was identified on chromosome 4 for HD and the other on Chr.6 for GPP. Furthermore, three regions carrying multiple QTLs were identified on chromosomes 1, 4 and 8 respectively. For example, on chromosome 8, three QTLs for HD, GW and PH, respectively were identified between RG885-GA408 in nonstress environment, but not in the stress environment. The comparative study of QTLs detected in extremely different (salt stress and nonstress) environments revealed that there existed several QTLs for important agronomic traits on chromosome 8 which were affected significantly by salt stress.     

Characterization of an ethylene receptor homolog gene from rice

Ethylene plays important roles in plant growth, development and stress responses. Its receptor genes have been studied in dicots such asArabidopsis, tobacco and tomato. However, no research has been reported for the ethylene receptors from monocots currently. In the present study, we cloned an ethylene receptor geneOSPK2 from rice and found that its encoded protein was divergent from the ethylene receptors from dicots. OSPK2 had a long extension in its N-terminal, followed by three transmembrane segments, a GAF domain, a putative kinase domain and a putative receiver domain. Although most of the domains were conserved, the expected phosphorylation site His and the phosphate receiver Asp have been replaced by Gln and Asn, respectively. This fact indicates that OSPK2 may not function as a histidine kinase in a phosphorelay manner, but rather play roles by other mechanism, probably through Ser/Thr kinase activity. The expression of theOSPK2 gene was investigated by RT-PCR method under different conditions. We found that this gene was apparently induced by wounding and PEG treatment, but not significantly affected by salt and ABA treatments. The differential expression of theOSPK2 gene may reflect its roles in mediating different abiotic stress responses, consistent with our previous studies on tobacco ethylene receptors.     

Clonorchis sinensis: molecular cloning and functional expression of novel cytosolic malate dehydrogenase

The NAD-dependent cytosolic malate dehydrogenase (cMDH, EC 1.1.1.37) plays a pivotal role in the malate-aspartate shuttle pathway that operates in a metabolic coordination between cytosol and mitochondria, and thus is crucial for the survival and pathogenicity of the parasite. In the high throughput sequencing of the cDNA library constructed from the adult stage of Clonorchis sinensis, a cDNA clone containing 1152bp insert was identified to encode a putative peptide of 329 amino acids possessing more than 50% amino acid sequence identities with the cMDHs from other organisms such as fish, plant, and mammal. But low sequence similarities have been found between this cMDH and mitochondrial malate dehydrogenase as well as glyoxysomal malate dehydrogenase from other organisms. Northern blot analysis showed the size of the C. sinensis cMDH mRNA was 1.2 kb. The cMDH was expressed in Escherichia coli M15 as a His-tag fusion protein and purified by BD TALON metal affinity column. The recombinant cMDH showed high MDH activity of 241 U mg(-1), without lactate dehydrogenase and NADP(H) selectivity. It provides a model for the structure, function analysis, and drug screening on cMDH.