EFFICIENT SYNTHESIS OF OLIGONUCLEOTIDE-PEPTIDE CONJUGATES ON LARGE SCALE

The conjugation of oligonucleotide phosphorothioates with antennapedia peptide was studied in detail to allow efficient preparation of the conjugates on up to 15 μmol scale. Under optimized conditions, the use of oligonucleotides and the peptide in an equimolecular ratio gave the desired conjugates in more than 60% isolated yield.     

A CONVENIENT METHOD FOR THE SYNTHESIS OF OLIGONUCLEOTIDE-CATIONIC PEPTIDE CONJUGATES

A method was developed for the synthesis of oligonucleotide-cationic peptide conjugates in solution phase by disulfide bond formation. Precipitation was avoided by the easily removable triethylammonium trifluoroacetate (TEATFAc) salt which served at the same time as a buffer of the reaction mixture. The fast and high yielding disulfide bond formation was due to the Npys thio protecting and activating group of Cys. A solution of the free 5′-thiol modified oligonucleotide obtained from Poly-Pak? purification was used for conjugation.     

A NOVEL APPROACH FOR THE SOLID PHASE SYNTHESIS OF DNA-PEPTIDE CONJUGATES

The strategy of this study involves automated synthesis of oligonucleotides on a CPG support using standard cyanoethyl phosphoramidite chemistry followed by covalent linkage to peptide fragments bearing a free terminal α-amino group and residues with protected side chains. Conjugation was formed through an alkyldiisocyanate linker. Conjugates wereisolated by cleavage from the solid support and deprotection in one step.     

CONVERGENT EVOLUTION OF SEXUAL DIMORPHISM IN SKULL SHAPE USING DISTINCT DEVELOPMENTAL STRATEGIES

Studies integrating evolutionary and developmental analyses of morphological variation are of growing interest to biologists as they promise to shed fresh light on the mechanisms of morphological diversification. Sexually dimorphic traits tend to be incredibly divergent across taxa. Such diversification must arise through evolutionary modifications to sex differences during development. Nevertheless, few studies of dimorphism have attempted to synthesize evolutionary and developmental perspectives. Using geometric morphometric analysis of head shape for 50 Anolis species, we show that two clades have converged on extreme levels of sexual dimorphism through similar, male‐specific changes in facial morphology. In both clades, males have evolved highly elongate faces whereas females retain faces of more moderate proportion. This convergence is accomplished using distinct developmental mechanisms; one clade evolved extreme dimorphism through the exaggeration of a widely shared, potentially ancestral, developmental strategy whereas the other clade evolved a novel developmental strategy not observed elsewhere in the genus. Together, our analyses indicate that both shared and derived features of development contribute to macroevolutionary patterns of morphological diversity among Anolis lizards.     

RECOGNITION OF DNA BY STRAND INVASION WITH OLIGONUCLEOTIDE-SPERMINE CONJUGATES

Modified oligonucleotides bearing spermine groups (ODN-sper) with increased binding affinity to DNA have been synthesized. The ability of these ODN-sper to bind within superhelical double-stranded DNA by strand invasion has been studied. The uptake by a supercoiled plasmid was 3 fold higher for the ODN-sper than for the unmodified oligonucleotides.     

PHOTOSENSITIZED AND CATALYTIC OXIDATION OF DNA BY METALLOPHTHALOCYANINE-OLIGONUCLEOTIDE CONJUGATES

The synthesis of new metallophthalocyanine-oligonucleotide conjugates is reported. These conjugates can cause sequence-specific photosensitized or catalytic oxidation of DNA by molecular oxygen.     

INHIBITION OF DNA SYNTHESIS IN CHICK EMBRYO CULTURES BY DEPRIVATION OF EITHER SERUM OR ZINC

The rate of DNA synthesis in cultures of chick embryo cells is proportional to the concentration of serum added. The concentration of serum required to stimulate DNA synthesis increases with cell population density and with the duration of culture after trypsinization. The increase of the serum requirement with population density is not caused by the depletion of serum constituents. The requirement of cells for external zinc in DNA synthesis also increases with population density and duration of culture. The kinetics of inhibition of DNA synthesis by deprivation of serum or zinc are similar. Serum deprivation, however, inhibits 2-deoxyglucose uptake and cell movement, but zinc deprivation does not. The deprivation of either serum or zinc inhibits RNA synthesis about twofold. Very low concentrations of actinomycin D prevent the resumption of RNA and DNA synthesis upon restoration of serum or zinc to deprived cultures.     

多肽固相序列分析载体的合成及应用

用合成的聚合物作载体,与模型15肽(纯品)偶联,使用Edman降解法进行多肽序列分析。比较了各种类型载体对肽的偶联效果。实验结果表明合成的大孔型四次乙基五胺类树脂载体已经达到国外同类产品水平。     

DESIGN AND SIMPLE ROUTES OF SYNTHESIS OF OLIGONUCLEOTIDE CONJUGATES FOR STUDIES OF DNA TRIPLE HELIX FORMATION

A series of oligonucleotides conjugated to intercalators, as well as fluorescent and lipophilic substances, minor groove binders and photoactive molecules were synthesized for studies of their ability to form a stable triple helix. Purine-rich short double stranded DNA fragments from HIV-1 genome and pyrimidine 16-mer oligodeoxyribonucleotide were used as models. A conjugate of a dipyrido[3,2-a:2′,3′-c]phenazine-ruthenium (II) complex and a triple helix-forming oligonucleotide was constructed. Upon sequence-specific duplex and triplex formation of the conjugate, the ruthenium complex becomes highly fluorescent. The attached ruthenium complex induces a stabilization of the DNA triple helix and a significant increase of the time of residence of the third strand on the duplex.     

胫骨判定性别的逐步判别分析

西安地区现代成人男女各50例的胫骨,进行12项测量,用逐步判别分析的方法进行研究。其结果:仅用下段宽判定性别,准确性达71％;而用下段宽,下段矢径和滋养孔平面最大矢径判定性别,准确性可达77％。并将该结果与美国白人和黑人的有关资料进行了对比。     

APPLICATION OF MITSUNOBU REACTION TO SOLID-PHASE PEPTIDE NUCLEIC ACID (PNA) MONOMER SYNTHESIS

ABSTRACT

PNA type I monomer backbone with a reduced peptide bond was synthesized on a Merrifield resin in Mitsunobu reaction of Boc-amino ethanol with resin-bound o-nitrobenzenesulfonylglycine. The pseudo dipeptide secondary amine group was deprotected by thiolysis and acylated with thymin-1-ylacetic acid. The monomer was released as a methyl ester. The procedure seems to be of general applicability and allows various modifications of PNA structure by using diverse alcohols and amino acid esters.     

BCL-2反义硫代磷酸寡脱氧核苷酸对原代急性白血病细胞选择性抑制作用

为探讨BCL-2反义硫代磷酸寡脱氧核苷酸(AS-PS-ODN,ASPO)对急性原代白血病细胞和正常或良性血液病骨髓细胞的作用是否存在差别。应用台盼蓝拒染试验测定细胞存活力;用造血祖细胞集落培养:粒—单系祖细胞集落(CFU-GM),多向祖细胞集落(CFU-Mix),后红系祖细胞集落(CFU-E)、前红系祖细胞集落(BFU-E)和白血病祖细胞集落(CFU-AML,CFU-ALL)培养检测细胞增殖能力;免疫细胞化学染色检测细胞BCL-2蛋白表达变化。结果发现(1)正常或良性血液病骨髓细胞经10μmol/L ASPO处理一周,同对照组比较:细胞生长数、CFU-GM、CFU-Mix、CFU-E、BFU-E及BCL-2蛋白表达均无显著差别(P<0.05)。(2)急性原代白血病细胞经5μmol/L ASPO处理一周,同对照组比较:细胞生长数显著减低;CFU-AML或CFU-ALL显著降低(P < 0.05),而CFU-GM明显增高(P< 0.05);对照组BCL-2蛋白表达率为77.92％±22.50％,ASPO组于培养的第3天为54.05％±20.20％(P<0.01)和第6天为55.35％±22.74％(P<0.05)均显著低于对照组。因此认为BCL-2ASPO具有选择性地抑制白血病细胞的增殖和BCL-2蛋白的表达的作用。     

固定化嗜热脂肪芽孢杆菌合成低聚半乳糖

利用海藻酸钙、明胶和壳聚糖为固定化载体包埋嗜热脂肪芽孢杆菌细胞合成低聚半乳糖 (GOS)。通过比较三种方法的酶活力回收、最适反应条件、GOS的得率和和载体机械强度 ,选择明胶作为固定化细胞的载体。反应体系的温度、pH、乳糖浓度、乳糖的转化率和载体的传质阻力对GOS合成有明显影响。在CSTR反应器中水解 60 %乳糖 ,GOS最大得率为31 2 % ,经过 96h( 8批反应 ) ,产物得率为原来的 88%。在空速 0 0 9h- 1条件下 ,利用填充床反应器连续水解乳糖 ,GOS的得率和反应器生产能力分别为 31 5%和 1 7 4g (L·h) ,连续反应1 40h,GOS得率下降 2 0 %。产物经过活性炭柱层柱分离纯化 ,通过13C NMR鉴定四糖的化学结构为 β D Gal ( 1→ 3) D Gal ( 1→ 6) D G ( 1→ 4) D Glu。     

STIMULATION OF BRAIN DOPAMINE SYNTHESIS BY GAMMA-HYDROXYBUTYRATE

Abstract— Gamma-hydroxybutyrate administration produces a marked selective increase of brain dopamine in different animal species. Following γ -hydroxybutyrate administration, dopamine accumulated in the basal ganglia of the rat and in the caudate nucleus of the rabbit at a rate which greatly exceeded the normal synthesis rate of the amine in these species. Dopamine accumulation was prevented by α -methyltyrosine. These data indicate that γ -hydroxybutyrate stimulates dopamine synthesis. In addition, γ -hydroxybutyrate increased the homovanillic acid level in the rat basal ganglia to a maximum of about 300 per cent of the normal level indicating that γ -hydroxybutyrate inhibits neither monoamine oxidase nor catechol O -methyltransferase in vivo. The possible mechanisms of dopamine accumulation following γ -hydroxybutyrate administration are discussed.     

抗癌药物紫杉醇的全合成—Holton合成紫杉醇路线的剖析

从全合成战略与路线,关键反应,保护基应用和立体化学方面对Holton的线性全合成紫杉醇路线进行剖析归纳。     

PLASMA MEMBRANE AND INTERNALIZED IMMUNOGLOBULINS OF LYMPH NODE CELLS STUDIED WITH CONJUGATES OF ANTIBODY OR ITS FAB FRAGMENTS WITH HORSERADISH PEROXIDASE

Normal rat and mouse lymphoid cells were incubated at 0°–4°C for 1 h with purified rabbit or sheep antirat (mouse) immunoglobulin (Ig)-horseradish peroxidase (PO) conjugates or with Fab fragments of antibody coupled with peroxidase. Cells were subsequently washed and incubated in fresh medium, without labeled antibody or Fab fragments for 5–30 min at 20° or 37°C. With the use of the diaminobenzidine (DAB) method, distribution of peroxidase was studied in the light and electron microscopes. Fab fragments of antirat Ig antibody were iodinated with ¹²⁵I and subsequently coupled with horseradish PO. Plasma membrane and internalized immunoglobulins were detected by electron microscope autoradiography and peroxidase cytochemistry. Single- (Fab-PO), and double- ([¹²⁵I]Fab-PO) labeled lymphoid cells showed identical patterns of surface or internal distribution of immunoglobulins. In the electron microscope, Fab-PO conjugates at 0°–4°C resulted in a diffuse specific staining of the plasmalemma of lymphocytes and plasma cells. Most of the small dark lymphocytes (T cells?) did not show plasma membrane Ig. Macrophages did not show plasmalemma staining, but displayed nonspecific cytoplasmic staining after incubation at 20° or 37°C with antibody or Fab-PO conjugates. Lymphocytes and plasma cells, after incubation with antibody-PO conjugates at 0°–4°C, had patchy deposits of oxidized DAB on their plasma membranes. Macrophages, similarly treated, had no plasmalemmal staining. Patch and cap formation on the plasma membrane of lymphocytes and plasma cells was seen regularly after antibody-PO incubation at 37°C. Internalization patterns were different in lymphocytes and plasma cells. In lymphocytes, peroxidase staining was observed in small round or oval vesicles clustered at one pole of the cell (30 min at 37°C). In plasma cells, peroxidase staining was seen in clusters of tubules resembling the Golgi apparatus. Internalization of plasma membrane IgG was less pronounced after antibody-PO labeling as compared to Fab-PO labeling.