Abstract:The interaction between aminoacyl-tRNA synthetases(aaRS) and tRNAs maintains the fidelity of protein biosynhesis. The specificity of recognition of tRNAs by aminoacyl-tRNA synthetases(aaRS) depends on the definite catalytical domain of aaRS and the distinctive tertiary structural comformation of tRNAs. Anticodon and acceptor stem (including position 73) play key roles in most recognition of tRNAs by aminoacyl-tRNA synthetases, other positions such as variable pocket,variable (stem) loop, even modified nucleotides are also important in some recognition.

Abstract:Two questions on iron metabolism in reticulocyte are deliberated. Firstly, how does reticulocyte acquire transferrin-bound iron? The current knowledge on transferrin-bound iron uptake by reticulocyte, a seven stepwise process, is summarized. Secondly, how does iron cross the endosome membrane in reticulocyte after it is released from transferrin? Some relevant hypotheses including membrane iron channel, iron carrier-mediated transport, the involvement of H^＋-ATPase, MIP system and function of free radical reactions in the process are discussed. Finally, some important aspects for further investigation are suggested.

Abstract:Interleukin 6 is a multiple function cytokine, playing an important role in modulating immune response, hematopoeisis, acute phase reaction and so on. On the other hand, over-expression of IL-6 relates to the pathogenesis and development of many kinds of diseases. IL-6 exerts its effect on the target cell through a two-chain receptor system, one is the ligand-binding chain (IL-6R) and the other is the signal transducer gp130. IL-6, IL-6R and gp130 interact through a heterohaxmer module, sequentially triggers the signal transduction within the cell. There exist two signal transduction pathways: Jak-STATs pathway and Ras-MAPK cascade pathway. Any factor that can block or interfere with the signal transduction of IL-6 will be a considerable strategy in treatment for IL-6 related diseases. These strategies include growth factors, monoclonal antibodies, antagonists, antisense gene and so on. The study on the pharmaceutical design and selection targeting to signal transduction of IL-6 will promote the treatment for IL-6-related diseases. The two-chain receptor system of IL-6 and its signal transduction have been reviewed, and the strategies in treatment for IL-6-related diseases have been elucidated.

Abstract:Vascular endothelial growth factor receptors are the membrane-spanning receptors which were found in vascular endothelial cells and induce the proliferation and differentiaion of endothelial cells. There are two receptors which can specially bind with VEGF. They are Flt and KDR, the gene structures and locations in the chromosome of flt and KDR were identified. Both Flt and KDR are receptors of type Ⅲ RTKs. Their structures are similar. There are seven immunoglobin-like sequence in extracellular domain. The catalytic domains in intracellular region were inserted by tyrosine kinase domains. Autophosphorylation was induced, which results in intracellular response. The VEGF repeptors play an important role in angiovascular, wound repair, inflammatory response, tumour growth and some cardiovascular diseases.

Abstract:In response to bacteria or trauma, insects produce a battery of antibacterial peptide or polypeptide such as cecropin, diptericin, attacin and defensin, the synthesis of which are induced in the fat body and secreted into the hemolymph where they act synergistically to kill the invading microorganisms. The insect host defence system shares common basic characteristics of the mammalian acute phase response, especially in the aspect of the coordinating gene expression, where similar cis-regulatory and inducible transactivator appear to play major roles.

Abstract:Nucleases play a direct and important role in DNA fragmentation which is a hallmark of apoptosis. The nucleases involved in apoptosis are divided into two types:divalent cations dependent nucleases and divalent cations independent nucleases.The divalent cations dependent nucleases mainly include nuc18,DNaseⅠ,Ca^2＋/Mg^2＋ nuclease,Ca^2＋/Mn^2＋ nuclease, DNaseγ, nuc58 and nuc40;The divalent cations independent nucleases mainly include DNaseⅡ and DNaseⅡ like nucleases.Moreover,the effect of nucleases on chromatin DNA degradation and the mechanism of this process were discussed.

Abstract:To study the damage of DNA, methodology of measuring DNA double-strand breaks(dsbs) is of critical importance. Many methods have been used, but each has its advantage and limitation. Recently, researchers often use some advanced methods, such as fluorescence in situ hybridization(FISH), comet assay (or single-cell electrophoresis, SCE), high-performance capillary electrophoresis (HPCE) etc.

Abstract:Sweet protein thaumatin is the sweetest substance known so far.Thaumatin has many features that make it attractive to food and feed manufacturers.Its nucleic acid sequence and amino acid sequence have been reported.Structure analysis showed that thaumatin has high stable tertiary structure. The substance mediated between thaumatin and microvilli of the taste bud pores has been found.The exact function of thaumatin and thaumatin like protein is still not clear. Thaumatin has been expressed in some procaryotic and eucaryotic expression systems, but no satisfied products can be got through the way of gene engineering by now.

Abstract:Three organogermanium compounds synthesized by the authors including carboxyethyl germanium sesquioxide (Ge-132), carbamoylethyl germanium sesquioxide (CGS) and α,β-dicarboxyethyl germanium sesquioxde (DGS) could significantly stimulate mouse peritoneal macrophages (Mφs) which mediate MTC effect against mouse ascites hepatoma cells with high lymph duct metastatic capacity (HCa-F₂₅/16A₃-F) and human monocytoid leukemic cells by oral administration at one dose of 100 mg/kg.The CGS and DGS were more effective than Ge-132 in enhancing MTC effect at the above dose,and CGS had the strongest effect. The Mφs activated in vivo by CGS, DGS and Ge-132 at one dose of 100 mg/kg showed increased incorporation of ［³H］ choline into phosphatidylcholine (PC), and the most significant increase was observed when Mφs were activated by DGS. Mφs activated in vivo by Ge-132 also showed increased incorporation of ［³²P］Pi and ［³H］choline into PC, and decreased incorporation of ［³²P］Pi and ［³H］inositol into PI when compared with resident peritoneal Mφs. No significant difference was observed on the incorporation of ［³²P］Pi and ［³H］inositol into polyphosphoinositide (PIP and PIP₂） between the Ge-132 activated Mφs and the resident peritoneal Mφs. The enhanced PC turnover of Mφs might be necessary for the expression of MTC in activated Mφs.

Abstract:Apolipoprotein E (ApoE) is strongly associated with late-onset familial and sporadic forms of Alzheimer's disease. Some myopathic changes which are similar to those seen in Alzheimer brain, that is, deposits of βAP and tau protein, could be induced by chronic intoxication with chloroquine. The influence of chloroquine treatment on ApoE expression in rat muscle was examined using reverse transcription followed by polymerase chain reaction (RT-PCR). A steadily expressed endogenous mRNA, glyceradehyde-3-phosphate dehydrogenase (G3PD) was served as an internal standard in PCR quantification. Amplification was found to be linear over a wide range of cycle number, and the efficiency was identical for target and control mRNA in RT-PCR. The expression of ApoE mRNA in rat muscle began to increase after 6 weeks of chloroquine treatment, and became 20-fold more than that in untreated control later on. The results suggest that ApoE may play roles in the pathologic changes in rat muscle caused by chronic intoxication with chloroquine.

Abstract:IL-1 and TNF have been found to act as protective agents from lethal doses of ionizing radiation in recent years. It was proposed that the mechanisms of the radioprotective effect of IL-1 and TNF may be resulted from to its selective stimulation of manganese supreoxide dismutase(Mn-SOD) expression on both RNA and protein level. Chinese hamster ovary(CHO) cells transfected with sense Mn-SOD cDNA showed decreased radiosensitivity after treatment with X-ray irradiation, whereas clones transfected with anti-sense Mn-SOD cDNA showed increased radiosensitivity. It was demonstrated that overexpression of Mn-SOD could promotes the survival of CHO cells from ionizing radiation.

Abstract:N-methyl-D-asparate-receptors (NMDAR) are implicated in several neuropathological conditions including epilepsy. As a model of epilepsy, genetically epilepsy-prone rat was chosen to invesitegate the changes in expression of NMDAR1 mRNA after seizure in different brain regions. The results showed that cerebral cortex, hippocampus, subcortex and inferior colliculus had a time-dependent modulation of the NMDAR1 mRNA expression and increased about 111%,113%,165%,202% above control values, respectively in 24h after seizure. This phenomenon demonstrates that NMDAR1 mRNA was regulated by seizure and may contribute to epileptic susceptibility.

Abstract:The transcriptional changes of α A-crystallin and β23-crystallin genes in response to various concentrations of selenite were studied in RLE cells in vitro. The results showed that along with the increasing of selenite concentration, α A-crystallin transcription decreased, then went up sharply at 5×10^－5 mol/L Na₂SeO₃ . The results suggested that α A-crystallin might at least respond to high concentration of selenite and express as a stress protein. But β23-crystallin gene transcription showed increasing followed by decreasing with the increase of selenite concentration. It indicated that selenium might play a critical role in lens epithelial cell differentiation.

Abstract:The phosphorescence properties of tryptophan (Trp), tyrosine (Tyr), pheny-lalanine (Phe), proline (Pro), and histidine (His) were investigated. The phosphorescence of Trp is the strongest (high quantum yield). Tyr is the next (about 1/10 of Trp) and Phe, Pro, His are weak (about 1/100 of Trp). The spectra of Tyr and Phe are short (λ_ex 284 and 276, λ_em 390 and 386 nm respectively), but Trp, Pro, His are long (λ_ex 290, 308 and 320 nm, respectively). The phosphorescence lifetime of Phe, Trp, are the longest (about 7 s), Tyr, Pro and His are short (2.84,1.31 and 0.49 s respectively). The phosphorescence spectra of amino acids in different alcohol (methanol, ethanol, n-propanol, n-butanol) are changed little, but the lifetime becomes shorter as the polarity of alcohol decreasing. The effect of pH on the spectra of amino acids were studied. The stokes energy loss and the excited pK^*_a were also measured.

Abstract:Antisense oligonucleotides can bind to a specific viral RNA, and hence inhibit the reproduction of virus selectively. Six tetradecyl modified antisense phosphothioate deoxyoligonucleotides were synthesized, antiviral assay showed that RDS-53, RDS-32 and RDS-33 targeting to the translation initiation site, 3′-repeated and 3′-terminal sequences of D2-04 RNA had fairly strong inhibitory activity.

Abstract:A procedure was used to obtain peptide fragments for sequence analysis from proteins separated by gel electrophoresis.After separation by SDS-polyacrylamide gel electrophoresis (SDS-PAGE),proteins were briefly stained with Coomassie blue,interested protein-containing bands were cut and loaded onto the wells of a new SDS-PAGE gel.The protein was digested by protease V8 during electrophoresis,the resulting peptide fragments were electroblotted onto polyvinylidene difluoride membrane,and then sequenced with protein sequencer.The method can be used not only to obtain amino acid sequences from N-terminal blocked proteins,but also to produce multiple and independent amino acid sequence information from normal proteins.

Abstract:A simple and efficient method for the purification of recombinant tissue-type plasminogen activitor(rt-PA) from a genetically manipulated CHO cell line(SGG) has been developed. The conditioned medium containing about 1500 U/ml of rt-PA from cultures of SGG cell in DMEM∶F12(1∶1) supplemented with 1% NBS was purified by a combination of absorbtion chromatography on MPG and affinity chromatography on Lysine-Sepharose 4B.The final product has a specific activity of 390 000 U/mg protein. The overall activity recovery was about 140% with 380 fold increase in specific activity. Analysis by SDS-PAGE in the presence of a reducing agent followed by silver staining showed one band with mass of molecular about 65 000 and two bands of 33 000～35 000. Reverse fibrin autography and Western blotting analysis showed that the product has natural t-PA characterization.

Abstract:A simple and rapid method for isolation and purification of gangliosides (Gls) from the rat brain is described. The gangliosides were isolated and purified by centrifugal mini-column chromatography. The rate of recovery of standard Gls was up to 97.64%, n=7, CV＜3%. No detective loss of Gls was demonstrated. The novel method offers a few advantages: 1.It is simple, rapid and efficient. 2.The thin layer chromatographic patterns of total Gls of samples obtained are clear and distinct. 3.Less solvent was consumed. Thus, the method is especially applicable to comparative and qualitative studies of gangliosides of micro samples, and to ganlioside metabolism research of tissues and cells in vitro.

Abstract:The rat liver tRNA^Ile gene has been synthesized before. Now the synthetic tRNA^Ile gene was transcripted in vitro with T7 RNA polymerase and the optimum reaction condition was investigated.

Abstract:Ficoll-400 discontinuous density gradient centrifugation was used to purify superficial yolk spheres under blastoderms of fertilized chicken eggs and the corresponding site of unfertilized eggs. Under microscope, the purified yolk spheres showed good morphology and no contamination from embronic cells was observed. The purified yolk spheres were lysed and digested with high concentration of proteinase K then extracted for long time with phenol. When subjected to agarose gel electrophoresis, the DNA showed a clear band. The recovery of DNA is approximately 10 ng per fertilized or unfertilized egg.

Abstract:The first strand cDNA liberary rich in cytokine cDNAs has been prepared from mRNA derived from several groups of activated lymphocyte by reverse transcription. Several Chinese-derived cytokine cDNAs were cloned successfully by PCR. It is suggested that the first strand cDNA liberary could provide a good templet for PCR amplification.

Abstract:A solid phase and competitive enzyme immunoassay for the determination of microalbumin in urine using rabbit anti-human albumin antibody, HRP-HSA and Nunclon microtiter strips was developed. Two chromogens: o-phenylenediamine (OPD) and 3,3,5,5-tetremethyl benzidine (TMB), sodium carbonate coated wells and glutaraldehyde coated wells was compared. The influences on the determination of the concentration of substrated, antigen and antibody was discussed. The optimal conditions for the assay was established.

Abstract:BIA technology (biomolecular interaction analysis) is a new concept by using newly developed biosensor technology. The interaction of biomolecular can be monitoring in real time and without the use of labels. The principles and application fields of this new technology are introduced. A series of application note for BIA technology in the next few journals will be published. Together with almost 400 publications in the scientific literature, the great value of BIA technology in research will be revealed.