Construction of Bifidobacterium Infantis/CD Targeting Gene Therapy System

Objective： To construct Bifidobacterium Infantis/CD targeting gene therapy system. Methods： CD gene was amplified from E. Coli K12λ using PCR method, pGEX-1LamdaT plasmid and CD gene were digested with dual restriction endonucleas of EcoR Ⅰ and BamH Ⅰ and two segments of 4.9 kb and 1.3 kb were obtained. T4 DNA ligase was added to these two segments to make a recombinant CD/pGEX-1LamdaT plasmid. Then the recombinant plasmid was transfected into Bifidobacterium Infantis by electroporation. The recombinant plasmid was extracted from the positively transfected Bifidobacterium Infantis and digested with dual restriction endonucleases. Then the size of digested fragments was detected and sequencing of the gene segment inserted in extracted recombinant plasmid was performed according to the method of Sanger dideoxynucleotide triphosphate chain termination. Results： 6.2 kb recombinant plasmid was obtained from the positively transfected bacterial colony of Bifidobacterium Infantis. After being digested with dual restriction endonucleases, two segments of approximate 4.9 kb and 1.3 kb were gained from the extracted recombinant plasmid, which were equal to the size of pGEX-1LamdaT plasmid and CD gene, respectively. The full length and sequence of nucleotide acid of the inserted gene in extracted recombinant plasmid was completely identical to the CD gene. Conclusion： The foreign gene, CD gene was correctly inserted into pGEX-1LambdaT plasmid and transferred into Bifidobacterium Infantis. Bifidobacterium Infantis/CD targeting gene therapy system was successfully constructed.

Modified RNA with a Phosphate-Methylated Backbone. A Serious Omission in Our (Retracted) Study at HIV-1 RNA Loops and Integrated DNA. Specific Properties of the (Modified) RNA and DNA Dimers

After the recent publication in the Journal of Biophysical Chemistry entitled “Retracted HIV Study Provides New Information about the Status of the in Vitro Inhibition of DNA Replication by Back-bone Methylation”, it is of importance to review the results of Buck’s group on the synthesis and conformation analyses of phosphate-methylated RNAs in order to afford information on the absence of a further investigation with regard to this de facto acceptable approach. In fact these compounds belong to the very first group of RNAs with a modified neutral backbone by phosphatemethylation. In contrast to the corresponding phosphate-methylated DNAs with a frozen B-conformation, the phosphate-methylated RNAs show an A-conformation. The latter is a prerequisite for duplex formation with (complementary) (natural) RNA. A number of experiments support this fundamental statement. After the HIV study was retracted, the overall results concerning the phosphate-methylated RNAs were published without mentioning Buck’s initial proof of concept and his contributions. Generally, the (modified) dimer RNAs and DNAs possess a number of specific biophysical properties. A novel explanation is given for conflicting structural determinations.

恢复connexin26表达联合载酵母菌胞嘧啶脱氨酶自杀基因纳泡杀灭膀胱癌细胞

目的分析载双基因的阳离子纳泡联合超声靶向微泡破坏技术进行基因转染的有效性,探索恢复或上调膀胱癌细胞的缝隙连接蛋白connexin26(Cx26)表达,能否增强自杀基因系统(yeast cytosine deaminase/5-fluorocytosine,YCD/5-FC)的旁观者效应,提高杀灭肿瘤细胞的效率。方法阳离子纳泡结合超声辐照(US)转染人膀胱癌T24细胞,荧光显微镜及流式细胞仪观测转染效率;qRT-PCR和Western blot检测质粒转染后的mRNA或蛋白相对表达量。将实验分为无处理空白对照、载pc DNA3.1-EGFP纳泡组、载Cx26纳泡组、载YCD纳泡组、载YCD+Cx26纳泡组;通过流式细胞术观察恢复Cx26表达后对膀胱癌细胞凋亡的影响。结果 qRT-PCR、Western blot显示纳泡结合超声辐照成功将目的基因转染并有效表达。恢复Cx26表达后,载YCD+Cx26纳泡组的细胞凋亡率为(60.68±2.61)%,明显高于单载YCD纳泡组的(46.42±2.13)%,差异有统计学意义(P<0.01)。结论恢复缝隙连接蛋白Cx26表达,可改善细胞间通讯连接,加强自杀基因系统YCD/5-FC的旁观者效应,促进肿瘤细胞凋亡,提高杀灭膀胱癌细胞的效率。

Outcomes of CAG Regimen for Refractory Biphenotypic Acute Leukemia Patients

Objective To evaluated the efficiency of low-dose cytosine arabinoside plus aclarubicin with concurrent administration of granulocyte colony-stimulating factor （CAG） regimen for refractory biphenotypic acute leukemia （BAL）. Methods We treated 5 refractory BAL patients by CAG regimen （10 mg.m 2 cytosine arabinoside subcutaneously administrated every 12 hours, day 1-14; 5-7 mg·m^-2 aclarubicin intravenously administrated daily, day 1-8; and concurrently used 200 μg·m^-2·d^-1 granulocyte colony-stimulating factor subcutaneously） from November 2002 to April 2007. The efficacy of the regimen was evaluated by response rate, and the side effects were also measured. Results The complete remission rate was 80%, median duration of absolute neutrophil count〈5.0×10^8/L and platelet count〈2.0×10^10/L was day 13 and day 1, respectively; and the infection rate was low （Ⅲ-Ⅳ infection rate, 20.00%）.

Effects of CPG ODN on biological behavior of PANC-1 and expression of TLR9 in pancreatic cancer

AIM:To determine the expression of toll-like receptor 9(TLR9) in pancreatic tumor and the effects of cytosine phosphate-guanosine oligodeoxynucleotides 2216(CPG ODN2216) on biological behavior of pancreatic carcinoma cell line PANC-1 and explore their clinical significance.METHODS:The immunohistochemistry and Western blot were used to determine the expression of TLR9 protein in pancreatic cancer tissues,and immunofluorescence staining was performed to detect the TLR9 protein expression in pancreatic carcinoma cell line PANC-1.To assess the effects of CPG ODN2216 on the invasive property of Panc-1 cells,in vitro cell adhesion,wound-healing scrape,and invasion and cell colony formation were evaluated.RESULTS:TLR9 was highly expressed in pancreaticcancer tissues and PANC-1 cells.The percentage of positive cells expressing TLR9 protein in human pancreatic tissues,paracancerous tissues and normal tissues were 73.3%,33.3% and 20.0%,respectively,and the protein expression level of TLR9 was gradually descending(P < 0.05).In vitro tests in wound-healing scrape,cell adhesion,colony formation and matrigel invasion showed that the adhesion and motility of PANC-1 cells in CPG ODN 2216 treatment group were signif icantly lower than in the control group(P < 0.05).The cell growth assay showed that the proliferative ability of PANC-1 cells in treatment group was significantly decreased and CPG ODN2216 had an inhibitive effect in the growth of Panc-1 cells in a dose and time-dependent manner(P < 0.05).CONCLUSION:The gene of TLR9 is correlated with the invasive and metastatic potential of human pancreatic carcinoma,and CPG ODN2216 induces the inhibition of migration and invasion of Panc-1 cells.

Specific CEA-producing colorectal carcinoma cell killing with recombinant adenoviral vector containing cytosine deaminase gene

AIM: To kill CEA positive colorectal carcinoma cells specifically using the E coli cytosine deaminase (CD) suicide gene, a new replication-deficient recombinant adenoviral vector was constructed in which CD gene was controlled under CEA promoter and its in vitro cytotoxic effects were evaluated. METHODS: Shuttle plasmid containing CD gene and regulatory sequence of the CEA gene was constructed and recombined with the right arm of adenovirus genome DNA in 293 cell strain. Dot blotting and PCR were used to identify positive plaques. The purification of adenovirus was performed with ultra-concentration in CsCl step gradients and the titration was measured with plaque formation assay. Cytotoxic effects were assayed with MTT method, The fifty percent inhibition concentration (IC(50)) of 5-FC was calculated using a curve-fitting parameter. The human colorectal carcinoma cell line, which was CEA-producing, and the CEA-nonproducing Hela cell line were applied in cytological tests. An established recombinant adenovirus vector AdCMVCD, in which the CD gene was controlled under CMV promoter, was used as virus control. Quantitative results were expressed as the mean +/- SD of the mean. Statistical analysis was performed using ANOVA test. RESULTS: The desired recombinant adenovirus vector was named AdCEACD. The results of dot blotting and PCR showed that the recombinant adenovirus contained CEA promoter and CD gene. Virus titer was about 5.0 X 10(14)pfu/L(-1) after purification. The CEA-producing Lovo cells were sensitive to 5-FC and had the same cytotoxic effect after infection with AdCEACD and AdCMVCD (The IC(50) values of 5-FC in parent Lovo cells, Lovo cells infected with 100 M.O.I AdCEACD and Lovo cells infected with 10 M.O.I AdCMVCD were 】15000, 216.5+/-38.1 and 128.8+/-25.4 micromol.L(-1), P【0.001, respectively), and the cytotoxicity of 5-FC increased accordingly when the m.o.i of adenoviruses were enhanced (The value of IC(50) of 5-FC was reduced to 27.9+/-4.2 micromol.L(-1) in 1000 M.O.I AdCEACD infected Lovo cells and 24.8+/-7.1 micromol.L(-1) in 100 M.O.I AdCMVCD infected Lovo cells, P【0.05, P【0.01, respectively). The CEA-nonproducing Hela cells had no effect after infection with AdCEACD, but Hela cells had the cytotoxic sensitivity to 5-FC after infection with AdCMVCD (The IC(50) of 5-FC in parent Hele cells and Hela cells infected with AdCMVCD at 10 M.O.I was 】15000 and 214.5+/-31.3 micromol.L(-1), P【0.001). AdCEACD/5-FC system also had bystander effect, and the viability was about 30 percent when the proportion of transfected cells was only 10 percent. CONCLUSION: The recombinant adenovirus vector AdCEACD has the character of cell type-specific gene delivery. The AdCEACD/5-FC system may become a new, potent and specific approach for the gene therapy of CEA-positive neoplasms, especially colon carcinoma.

Killing effects of cytosine deaminase gene mediated by adenovirus vector on human pancreatic cancer cell lines in vitro

OBJECTIVE: To evaluate the killing effects of the cytosine deaminase (CD) gene mediated by adenovirus vector on human pancreatic cancer cell lines in vitro. METHODS: The CD gene was cloned into pAdTrack-CMV-CD, and pAdTrack-CMV-CD and pAdEasy-l were recombinated in bacteria. The newly recombinated Ad-CD containing green fluoreseent protein (GFP) was propagated in 293 cells and purified by cesium chloride gradient centrifugation. Human pancreatic cancer cell lines Patu8988 and SW1990 were infected with this virus, then 5-FC was added. XTT assay was used to estimate relative numbers of viable cells. RESULTS: The positive clones were selected by using endonuclease to digest the combinatants and the concentration of viral liquids containing the CD gene was 2×1O^(11) pfu/ml. It was found that significant cytotoxic activities were possesscd by 5-FC for the CD gene transduced pancreatic cell lines, but little effects exerted on the nontransduced pancreatic carcinoma cells. CONCLUSIONS: The CD gene mediated by adenovirus with a high infectivity is efficient for gene therapy of pancreatic carcinoma cell lines. These data demonstrate the therapeutic efficacy of an enzyme prodrug strategy in experimental pancreatic cancer.

Preliminary Studies on Base Substitutions and Repair of DNA Mismatch Damage Stimulated by Low Energy N^+ Ion Beam Implantation in Escherichia coli

Ever since the low energy N+ ion beam has been accepted that the mutation effects of ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences based on naked DNA irradiation in support of a mutation spectrum appears to be consistent, but direct proof of such results in vivo are limited. Using mutS, dam and/or dcm defective Eschericha coli imitator strains, an preliminary experimental system on induction of in vivo mutation spectra of low energy N+ ion beam has been established in this study. It was observed that the mutation rates of rifampicin resistance induced by N+ implantation were quite high, ranging from 9.2 x 10~8 to 4.9× 10~5 at the dosage of 5.2×1014 ions/cm2. Strains all had more than 90-fold higher mutation rate than its spontaneous mutation rate determined by this method. It reveals that base substitutions involve in induction of mutation of low energy nitrogen ion beam implantation. The mutation rates of mutator strains were nearly 500-fold (GM2929), 400-fold (GM5864) and 6-fold larger than that of AB1157. The GM2929 and GM5864 both lose the ability of repair DNA mismatch damage by virtue of both dam and dcm pathways defective (GM2929) or failing to assemble the repair complex (GM5864) respectively. It may explain the both strains had a similar higher mutation rate than GM124 did. It indicated that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N+ implantation. The further related research were also discussed.

Bifunctional chimeric SuperCD suicide gene -YCD: YUPRT fusion is highly effective in a rat hepatoma model

AIM： To investigate the effects of catalytically superior gene-directed enzyme prodrug therapy systems on a rat hepatoma model. METHODS： To increase hepatoma cell chemosensitivity for the prodrug 5-fluorocytosine （5-FC）, we generated a chimeric bifunctional SuperCD suicide gene, a fusion of the yeast cytosine deaminase （YCD） and the yeast uracil phosphoribosyltransferase （YUPRT） gene. RESULTS： In vitro stably transduced Morris rat hepatoma cells （MH） expressing the bifunctional SuperCD suicide gene （MH SuperCD） showed a clearly marked enhancement in cell killing when incubated with 5-FC as compared with MH cells stably expressing YCD solely （MH YCD） or the cytosine deaminase gene of bacterial origin （MH BCD）, respectively. In vivo, MH SuperCD tumors implanted both subcutaneously as well as orthotopically into the livers of syngeneic ACI rats demonstrated significant tumor regressions （P〈0.01） under both high dose as well as low dose systemic 5-FC application, whereas MH tumors without transgene expression （MH naive） showed rapid progression. For the first time, an order of in vivo suicide gene effectiveness （SuperCD〉〉 YCD〉〉BCD〉〉〉negative control） was defined as a result of a direct in vivo comparison of all three suicide genes. CONCLUSION： Bifunctional SuperCD suicide gene expression is highly effective in a rat hepatoma model, thereby significantly improving both the therapeutic index and the efficacy of hepatocellular carcinoma killing by fluorocytosine.

N-terminal and C-terminal cytosine deaminase domain of APOBEC3G inhibit hepatitis B virus replication

AIM: To investigate the effect of human apolipoprotein B mRNA-editing enzyme catalytic-polypeptide 3G (APOBEC3G) and its N-terminal or C-terminal cytosine deaminase domain-mediated antiviral activity against hepatitis B virus (HBV) in vitro and in vivo. METHODS: The mammalian hepatoma cells HepG2 and HuH7 were cotransfected with APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain expression vector and 1.3-fold-overlength HBV DNA as well as the linear monomeric HBV of genotype B and C. For in vivo study, an HBV vector-based mouse model was used in which APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain expression vectors were co-delivered with 1.3-fold-overlength HBV DNA via high-volume tail vein injection. Levels of hepatitis B virus surface antigen (HBsAg) and hepatitis B virus e antigen (HBeAg) in the media of the transfected cells and in the sera of mice were determined by ELISA.The expression of hepatitis B virus core antigen (HBcAg) in the transfected cells was determined by Western blot analysis. Core-associated HBV DNA was examined by Southern blot analysis. Levels of HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by quantitative PCR and quantitative RT-PCR analysis, respectively. RESULTS: Human APOBEC3G exerted an anti-HBV activity in a dose-dependent manner in HepG2 cells, and comparable suppressive effects were observed on genotype B and C as that of genotype A. Interestingly, the N-terminal or C-terminal cytosine deaminase domain alone could also inhibit HBV replication in HepG2 cells as well as Huh7 cells. Consistent with in vitro results, the levels of HBsAg in the sera of mice were dramatically decreased, with more than 50 times decrease in the levels of serum HBV DNA and core-associated RNA in the liver of mice treated with APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain as compared to the controls. CONCLUSION: Our findings provide probably the first evidence showing that APOBEC3G and its N-terminal or C-terminal cytosine deaminase domain could suppress HBV replication in vitro and in vivo.

IS HYPOMETHYLATION OF CELLULAR DNA A STEP REQUIRED IN THE INITIATION PROCESS OF CHEMICAL CARCINOGENESIS

The level of DNA methylation in carcinogen treat-ed cells were determined by HpaII restriction frag-ment length analysis of the newly replicated DNAslabelled with H-TdR 24 hr prior to harvesting aswell as by direct HPLC measurement of the 5-methyl-cytosine(~mC)contents of the cellular DNAs.

Density function theory study on the interaction between camptothecin and cytosine

Density function M06 method has been used to optimize the geometries of camptothecin-cytosine at 6-3 I＋G＊ basis. Finally, thirteen stabilized complexes have been obtained. Theories of atoms in molecules （AIM） and natural bond orbital （NBO） have been utilized to investigate the hydrogen bonds involved in all the complexes. The interaction energies of all the complexes are corrected by basis set superposition error （BSSE）. By the analysis of complexes interaction energy, charge density, second- order interaction energies E（2）; it is indicated that the complex 6 is the most stable structure.

Highly efficient CRISPR-SaKKH tools for plant multiplex cytosine base editing

Base editing, as an expanded clustered regularly interspaced short palindromic repeats(CRISPR)-Cas genome editing strategy, permits precise and irreversible nucleotide conversion. SaKKH, an efficient variant of a Cas9 ortholog from Staphylococcus aureus(SaCas9), is important in genome editing because it can edit sites with HHHAAT protospacer adjacent motif(PAM) that the canonical Streptococcus pyogenes Cas9(SpCas9) or its variants(e.g. xCas9, Cas9-NG) cannot. However, several technical parameters of SaKKH involved base editors have not been well defined and this uncertainty limits their application. We developed an effective multiplex cytosine base editor(SaKKHn-pBE) and showed that it recognized NNARRT, NNCRRT, NNGRGT, and NNTRGT PAMs. Based on 27 targets tested, we defined technical parameters of SaKKHn-pBE including the editing window, the preferred sequence context, and the mutation type. The editing efficiency was further improved by modification of the SaKKH sgRNA. These advances can be applied in future research and molecular breeding in rice and other plants.

Research of total levels on DNA methylation in plant based on HPLC analysis

HPLC analysis is important for determination of total level on DNA methylation in plants. It can be used to help characterise epigenetic changes during growth, development and stress. HPLC methods have been optimised for mammalian and microbial DNA, but not for plants. This article examines several important factors in the HPLC analysis of plant DNA methylation including extraction and purification of DNA and HPLC conditions choice by using leaves of rice seedling. The experimental results showed that RNA of nucleic acid was removed by using RNase A. This study also identified critical components of HPLC analysis. With the optimized method of HPLC conditions, the better result was achieved in the chromatogram of cytosine and 5-methylcytosine in genomic DNA acid hydrolysis. The study would offer a comprehensive guide for the stringent analysis of DNA methylation in plants.

Analysis of DNA Cytosine Methylation on Cotton under Salt Stress

DNA methylation,especially methylation of cytosine in eukaryotic organisms,has been implicated in gene regulation,genomic imprinting,the timing of DNA replication,and determination of chromatin structure.It was reported that 6.5% of the whole cytosine residues in the nuclear DNA in

Therapeutic effects of combined suicide gene and granulocyte-macrophage colony stimulating factor gene transfer on erythroleukemia in mice

Adenoviruses harboring E. coli. cytosine deaminase(CD) gene (Ad-CD) and murine granulocyte-macrophage colony stimulating factor (GM-CSF) gene(Ad-GM-CSF) were used for gene transfer in vivo.(C57BL/6 mice were inoculated subeutaneously with FBL-3 erythroleukemia cells and three days later treated withadenovirus injection at the site of tumor inoculation.

Adenovirus-mediated tissue specific cytosine deaminase gene therapy for human hepatocellular carcinoma with different AFP expression level

Hepatocellular carcinoma (HCC) is one of the mostcommon cancers in the world, especially in East Asia.There is no standardized or effective strategy could beadapted routinely except of some early diagnosedpatients, and the prognosis is poor. In recent years, genetherapy has become a standard experimental approach fortreating cancers that have escaped conventionaltherapies. One such an approach is to confer the tumorcells with sensitivity to chemical reagents through

Theoretical investigations of collision dynamics of cytosine by low-energy (150-1000 eV) proton impact

Using a real-space real-time implementation of time-dependent density functional theory coupled to molecular dynamics（TDDFT-MD） nonadiabatically,we theoretically study both static properties and collision process of cytosine by150-1000 eV proton impact in the microscopic way.The calculated ground state of cytosine accords well with experiments.It is found that proton is scattered in any case in the present study.The bond break of cytosine occurs when the energy loss of proton is larger than 22 eV and the main dissociation pathway of cytosine is the breaks of C1 N2 and N8 H10.In the range of 150 eV≤Ek≤360 eV,when the incident energy of proton increases,the excitation becomes more violent even though the interaction time is shortened.While in the range of 360 eV<Ek≤1000 eV,the excitation becomes less violent as the incident energy of proton increases,indicating that the interaction time dominates mainly.We also show two typical collision reaction channels by analyzing the molecular ionization,the electronic density evolution,the energy loss of proton,the vibration frequency and the scattering pattern detailedly.The result shows that the loss of electrons can decrease the bond lengths of C3 NS and CSN6 while increase the bond lengths of C4 H11,C5 H12 and C4 C5 after the collision.Furthermore,it is found that the peak of the scattering angle shows a little redshift when compared to that of the loss of kinetic energy of proton.

INHIBITION OF NF-κB ACTIVITY ENHANCED CYTOSINE ARABINOSIDE INDUCED APOPTOSIS IN LEUKEMIC CELL LINE HL60-N

Objective: To explore the effects of dexamethasone (DXM) and vincristine (VCR) on cytosine arabinoside (Ara-C) induced apoptosis and activation of nuclear factor-k-gene binding (NF-kB) in leukemic cell line HL60-n. Methods: Apoptosis of HL60-n cells was analysed by TdT-mediated X-dUTP nick and end labeling (TUNEL) and DNA electrophoresis. NF-kB activity of HL60-n cells was detected by electrophoretic mobility shift assay (EMSA). Results: There was slight activation of NF-kB in HL60-n cells without drug induction. Ara-C at 1 mmol/L significantly enhanced the activation of NF-kB in HL60-n cells. The level of NF-kB activation induced by DXM at 1 mmol/L or VCR at 0.1 mmol/L had no significant difference compared with that of the control group. However, in HL60-n cells pre-treated with 1 mmol/L of DXM or 0.1 mmol/L of VCR, the activation of NF-kB induced by 1 mmol/L of Ara-C was significantly suppressed with inhibition rates of 31.0% and 47.0%, respectively. The apoptosis rates of HL60-n cells induced by 1.0 mmol/L, 10 mmol/L and 100 mmot/L Ara-C were 45.003.16%, 61.883.40% and 77.624.75%, respectively. The apoptotic rates of HL60-n cells induced by DXM at 1 mmol/L or VCR at 0.1 mmol/L were similar to that of the control group. However, either DXM at 1 mmol/L or VCR at 0.l mmol/L could enhance the apoptosis of HL60-n cells induced by Ara-C at 1 mmol/L with rates of 39.1% and 59.2%, respectively. Conclusion: Ara-C can induce apoptosis and activation of NF-kB in HL60-n cells. The mechanism of increased apoptosis of HL60-n cells by DXM or VCR may be related to suppression of NF-kB activation.

Solution and Thermodynamic Studies on Binary and Ternary Complexes of Lanthanides

The interactions of La（ Ⅲ ）, Pr（ Ⅲ ）, Nd（ Ⅲ ）, Sm（ Ⅲ ）, Eu（Ⅲ）, Gd（ Ⅲ ）, Dy（ Ⅲ ）, and Yb（ Ⅲ ） with cytosine, 5-bromocytosine, 5-azacytosine and 5-flurocytosine as primary ligands （L） and guanine （A） as secondary ligand for both binary （ 1 ： 1 ） as well as ternary （ 1 ： 1 ： 1 ） systems were investigated by potentiometric equilibrium measurements at 25, 35 and 45 ℃ in aqueous solution （ionic strength, μ = 0.1 mol·dm^-3 NaNO3）. The stability constants of the binary （ 1 ： 1 ） and ternary （ 1 ： 1 ： 1 ） metal-ligand complexes follow the following order La 〈 Pr 〈 Nd 〈 Sm 〈 Eu 〉 Gd 〈 Dy 〉 Yb. Results also indicate that the ternary lanthanide complexes of La（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Dy（Ⅲ）, and Yb（ Ⅲ ） are more stable than corresponding binary lanthanide complexes. The enthalpy （△Hf^o） and entropy （△Sf^o） changes for the formation of binary and ternary complexes were calculated from temperature coefficient data. The △△Sf^o values are positive for all the metal ligand systems. The negative △△Hf^o values indicate the extra stability of the ternary complexes by the exothermic enthalpy changes （△△Sf^o = △TSf^o - △BSf^o and △△Hf^o = △THf^o - △BHf^o where △TSf^o, △THf^o and △BSf^o, △BHf^o are the entropy and enthalpy values associated with the ternary and binary complexes, respectively）. It was also proposed that the guanine is bonded to metal ions through N1/C6 = O and N7 whereas cytosine and its derivatives are bonded through N3 atoms in ternary complexes.