ENDOTOXIN REMOVAL BY MEMBRANE AFFINITY CHROMATOGRAPHY

Endotoxin was removed by membrane affinity chromatography. Macropore cellulose membrane was prepared from filter paper by alkaline treatment and chemical crosslinking, and was used as stationary phase for affinity chromatography. The matrix membrane was derived by hexamethylenediamine and activated by glutaraldehyde before histidine was immobilized as affinity ligand. A membrane cartridge containing 40 sheets of affinity membrane was also prepared, which can be used to remove pyrogen from aqueous solutions.

p53-dependent and independent apoptosis induced by ionizing radiation in murine bone marrow cells

APOPTOSIS or programmed cell death is a model of cell death, along with typical morphological and biochemical changes. The cell death, occurring during embryonic development, T and B cell maturation and endocrine-induced atrophy, is a physiological apoptosis which controls the amount of cells in the body. Apoptosis can also be induced by various factors, such as ionizing radiation and anti-tumour agents which damage DNA, and has been proposed to be a consequence of the induced expression of some tumour-related genes or increase of the proteins sta-

Phenomenon and mechanism of "secondary damage" during repair of DNA damage in irradiated mammalian cells

By means of comet assay, a study of kinetics curve of DNA damage repair in irradiated SX-9 cells that came from mouse breast cancer proceeded. It was found that while the initial DNA damages had nearly been repaired, DNA damages arose for the second time, then they were repaired again. As a result, a phenomenon of "secondary damage" was found during the repair of DNA damages in irradiated SX-9 cells. Further research illuminated that 3-aminobenzamide (3AB), which is an inhibitor of poly (ADP-ribose) polymerase, could change the proceeding of "secondary damage". For this reason it is possible that there exists some inner relationship between the phenomenon of "secondary damage" and the function of poly(ADP-ribose) polymerase.

Effect of antisense oligonucleotides targeting telomerase catalytic subunit on tumor cell proliferation in vitro

To screen specific antitumor drugs targeting telomerase catalytic subunit (hEST2), 12 different hEST2 antisense oligonucleotides were designed based on hEST2 mRNA second structure and transfected into tumor cell lines by the lipofectin-mediated method. Cell growth activity was evaluated by MTT assay. HEST212 was picked out and its specificity, antitumor tree and continuous effect were analyzed. The results showed that hEST212 had promising anti-tumor activity in vitro, hEST2 can be used as a pratical target and an antisense drug candidate for cancer.

Progress in study of structure-function relationship and protein engineering of plasminogen activators

Thrombolytic agents play an important role in the treatment of thrombus diseases. In clinic,traditional thrombolytic agents always resulted in the side effect of systemic thrombolysis because of the shortcomings, such as short half-life, poor specificity of thrombus. Recently, with the development of knowledge of the relationship between their structure and function, a series of new thrombolytic agents were constructed by means of molecular biological techniques. Developing new types of thrombolytic agents is of great significance for more effective treatment of cardiovascular diseases. The latest knowledge of the structure-function relationship of t-PA and u-PA and the progress in development of new thrombolytic agents are reviewed.

Bioinformatics, robust realm based upon multidisciplinary knowledge of biological data and computational techniques

The accumulation of the large amount of biological data concerning with gene and protein research has proposed that it is necessary to abstract the biological significance from these data. Then the bioinformatics, equipped with the most advanced computational techniques and supported by the latest biological research, has emerged for this purpose. Some recent information on the developing bioinformatics, associated with the uniform resource location addresses of those available resource sites that support hyper-text or general file transfer proto-

ATM acts in DNA damage signal transduction by catalyzing protein phosphorylation

In order to investigate ATM in mediating DNA damage signal to p53 in the cellular response to IR, kinase activities of ATM and c-Abl immunoprecipitates and its activation by IR and damaged DNA have been analyzed. Results demonstrate that deficient ATM caused failure to activate phosphorylation of many proteins in response to radiation . ATM

Establishment of Chlamydomonas reinhardtii chloroplast expression

An expression vector pACⅢ containing the chimeric gene HAV- VP3P1 and HCV-C gene has been constructed and transferred to C. reinhardtii by the biolistic method. The trans-formants have been identified by PCR, Southern-blotting, Northern-blotting and Western-blotting assays after selecting on resistant medium and incubating in the dark. The results