The Application of Heating Effect in Breeding of Microorganism / 微生物学通报

Advances in mechanism and application of the heating effect in breeding of microorganism are reviewed in this paper. Heat produces mutagenesis effect and screening effect. Heating mutagenesis effect is occurred through the substitution of G-C base pair induced by heat, and heating screening effect produces higher forward mutation rate induced by other mutagens.

Isolation and Purification of Antibiotic from the Fermentation Broth of Micromonospora carbonacea JXNU-1 and Its Physical-chemical Properties / 微生物学通报

Based on the strain of Micromonospora carbonacea JXNU-1 with board-spectrum antimicrobial activity, the technology for the isolation and purification of antibiotic from the fermentation broth of the Micromonospora carbonacea, and its physical-chemical properties were studied. The results showed that, the antibiotic was stable under the condition of high temperature and alkali, but not in acid solution. After the pretreatment of centrifugation and filtration to remove the cells and lipids, the antibiotic was absorbed to negative exchange resin, and the impurity was excluded when 2 mol/L NaCl was used as primary eluent. The antibiotic could be eluted with 20% alcohol as eluent, and the eluting speed of the antibiotic was greatly accelerated as 2 mol/L NaCl was added into 20% alcohol as final eluent. Aqueous solution of the antibiotic was yielded from the alcohol-salt eluant by decompression concentration to wipe off alcohol and by dialysis to exclude salt. One active component was detected in antibiotic solution by paper chromatography, and theHPLC purity was over 99%. As the antibiotic shows positive color-forming reaction to Molish reagents, Benedict’s reagents and Diohenvlamine reagents, combined with the characteristics of absorption spectra, it is deduced that the antibiotic belongs to nucleoside antibiotics.

Rhein lysinate induces apoptosis in breast cancer SK-Br-3 cells by inhibiting HER-2 signal pathway / 药学学报

This study is to investigate the effect of rhein lysinate on inducing human breast cancer cell line SK-Br-3 apoptosis and the role of HER-2 signal pathway in the apoptosis. MTT assay was used to detect SK-Br-3 cell proliferation. Cell cycle and apoptosis were analyzed by flow cytometry. The protein expression and the protein phosphorylation of HER-2 signal pathway were detected by Western blotting. The level of HER-2 mRNA was detected by RT-PCR and the level of HER-2 expression was also detected by immunofluorescence cytochemical methods. The results showed that rhein lysinate remarkably inhibited breast cancer SK-Br-3 cell proliferation. The IC50 value for 48 h treatment was 85 micromol x L(-1). Apoptosis in SK-Br-3 cells was induced by rhein lysinate in a dose dependent manner. The protein expressions of HER-2, NF-KB, and the protein phosphorylation of HER-2 were downregulated, however the protein expression of p53 and p21 was upregulated after rhein lysinate treatment. The level of HER-2 mRNA decreased by using RT-PCR assay and the level of HER-2 expression was also decreased by using immunofluorescence cytochemical assay after rhein lysinate treatment. It can be concluded that rhein lysinate could inhibit SK-Br-3 cell proliferation and induce apoptosis. HER-2/NF-kappaB/p53/p21 signal pathway might be involved in this process. Rhein lysinate has a good prospect to be an adjuvant chemotherapeutic drug.

Human HSF1 mutants and their applications / 生物工程学报

Heat shock factor 1 (HSF1) is the key protein in regulating stress response. It can be activated under heat, oxidative or another stress conditions. Dominant-positive and dominant-negative HSF1 are two types of HSF1 mutants. Both of them gain the DNA binding activity in the absence of stress. In addition, dominant-positive HSF1 acquires transcriptional activity, which dominant-negative HSF1 does not acquire. In this paper, the progress of using these HSF1 mutants in the research of cancer, neurodegenerative disorders and cardiovascular diseases will be discussed.

Chemosensitivity of mdr1 gene overexpressed multidrug resistant cancer cells to lidamycin / 药学学报

<p><b>AIM</b>To investigate the chemosensitivity to lidamycin (C-1027) in mdr1 gene overexpressing cancer cell lines established by drug induction and by gene-transfection.</p><p><b>METHODS</b>DNA was cloned by RT-PCR and then eukaryotic expressing recombinant plasmid pcDNA3. 1/mdrl was constructed. Using Lipofectamine 2000, a strain of stably transfected human hepatoma cancer cells, HepG2/mdrl, was obtained. The mdr1 mRNA level, P-glycoprotein (P-gp) level and the activity of P-gp to extrude drugs in cancer cells were determined by RT-PCR, immunofluorescence analysis and rhodamine 123 efflux assay. The chemosensitivity of cancer cells with low or high mdr1 expression to lidamycin and other antitumor drugs was tested by MTT assay.</p><p><b>RESULTS</b>The mdr1 mRNA and P-gp levels in KBv200, MCF-7/ADR, and stably transfected HepG2/mdr1 cells were much higher than that in respective parent KB, MCF-7 and HepG2 cells. The IC50 values of lidamycin for KBv200, MCF-7/ADR and HepG2/mdrl cells were (0.24 +/- 0.20) nmol x L(-1), (0.028 +/- 0.011) nmol x L(-1), and (0.020 +/- 0.011) nmol x L(-1), respectively. Compared with parental cells, the values of resistant fold for KBv200, MCF-7/ADR and HepG2/mdr1 cells to lidamycin were 6.8, 1.6 and 1.3 fold; to adriamycin were 37.2, 181.3 and 8.8 fold; to taxol were 336.8, 49.2 and 40.3 fold, respectively.</p><p><b>CONCLUSION</b>Lidamycin is highly active to multidrug resistant cancer cells. The chemosensitivity of those resistant cancer cells to lidamycin is approximately at the similar level as that of parent cancer cells.</p>

Lidamycin inhibits the cancer cell PKC activity induced by basic fibroblast growth factor / 药学学报

<p><b>AIM</b>To study the mechanism of inhibition of basic fibroblast growth factor (bFGF) related signal transduction by lidamycin in cancer cells.</p><p><b>METHODS</b>MTT assay was used to determine the growth inhibitory effect of lidamycin (LDM) and adriamycin (ADR) in several cancer cell lines. The inhibition of bFGF bound to its receptor by LDM was measured with [125I]-bFGF binding assay. Intracellular Ca2+ stimulated by bFGF was measured by Fura-3. The formation of bFGF-receptor immune complex and the inhibitory effect of LDM on the activity of PKC isoenzymes induced by bFGF in cancer cells were identified by Western blotting analysis.</p><p><b>RESULTS</b>LDM displayed extremely potent growth inhibitory effect on several cancer cell lines in a dose-dependent manner. A comparison of the IC50 values showed that the effect of LDM was 1000-fold more potent than that of ADR. LDM blocked the specific binding of [125I]-bFGF to rat lung membranes with an IC50 value of 2.0 x 10(-4) nmol x L(-1). As detected by anti-FGFR specific antibody, LDM inhibited the formation of bFGF-receptor immune complex. bFGF induced cytosolic Ca2+ response was obstructed by pretreatment with 10 nmol x L(-1) LDM. Immunoblotting demonstrated that LDM inhibited the activity of PKC isoenzymes in cancer cells stimulated with bFGF.</p><p><b>CONCLUSION</b>The blocking of bFGF receptors in the signal transduction pathway may be involved in the effect of LDM on cancer cells.</p>

Isolation and Identification of a Strain of Micromonosporawith Broad-spectrum Antimicrobial Activity / 微生物学通报

A rare strain of actinomycetes, with broad-spectrum antimicrobial activity, was isolated from the soil samples from the farmland in the area of Yaohu lake in Nanchang. The information about the taxonomic identification, such as the morphology, physiological properties, cell components and 16S rRNA gene se-quences, suggested that the rare strain of actinomycetes was identified as Micromonospora carbonacea.