Expression of soluble, active human macrophage colony stimulating factor in Escherichia coli

Human macrophage colony stimulating factor (M-CSF) has been successfully overexpressed in Escherichia coli AD494 (DE3) with an expression level of approximate 26% of the total cellular proteins. The truncated human M-CSF gene encoding the amino-terminal 149 amino acids was subcloned into the prokaryotic expression vector pET11d under the control of the inducible T7 promoter. Nearly 40% of the recombinant protein was in the soluble fraction which showed obvious stimulating effects on mouse macrophage colony formation and had an M-CSF specific activity of approximately 1 x 10(6) units/mg soluble protein.

[Protective effects of beta-carotene liposome against rat neutrophile membrane damage caused by intra- or extra-cellular reactive oxygen species]

In this experiment the protective effects of beta-carotene (beta-C) liposome against rat neutrophile membrane damage caused by extracellular or intracellular reactive oxygen were species (ROS) investigated by means of fluorescence labels 1, 6-diphenyl-1,3,5 hexatriane (DPH) and N-(3-pyrene) maleimide (N-(3p)M). The extracellular ROS include the singlet oxygen (1O2) generated by photoreaction of sensitizer rosebengal and the superoxide anion (O2-.) produced by xanthine/xanthine oxidase reactive system. The intracellular ROS was sensitizer rosebengal and superoxide anion (O2-.) produced by xanthine/xanthine oxidase reactive system while the intracellular oxygen was generated by stimulating neutrophile respiratory burst with opsonized zymosan. No change in the peak or shape of fluorescent excitation and emission spectra was found for either of the two labels. The results of fluorescent polarization value in the membrane showed that beta-C liposome could significantly inhibit the damage of rat neutrophile membrane protein reacted either by intracellular generated reactive oxygen species or by extracellular generated O2-. or 1O2. It could also inhibit the injury of the rat neutrophile membrane lipid reacted by extracellular reactive oxygen species. However, the protective effects of beta-C liposome against membrane lipid damage reacted by intracellular reactive oxygen species by at the same concentration as those on membrane protein were not significant, which could be partly explained by relatively higher damage level of rat neutrophile membrane lipid domain reacted by intracellular reactive oxygen species than that of the membrane protein domain.

Expression of cecropin CMIV fusion protein in E. coli under T7 promoter

A synthetic gene coding for cecropin CMIV from Bombyx mori was cloned into plasmid pEZZ318 and fused to a DNA segment encoding the signal peptide of Staphylococcal protein A and IgG binding domain. The fusion gene was then subcloned into expression vector pET11c under the control of T7 promoter and expressed in E. coli. The fusion protein did not exhibit any antibacterial activity either in cell lysate or in medium. After cleavage from the fusion protein with CNBr the biological activity of recombinant cecropin CMIV was obtained.

Isolation of virus-neutralizing RNAs from a large pool of random sequences

RNA and ribonuclease-resistant RNA analogs that bound and neutralized Rous sarcoma virus (RSV) were isolated from a large pool of random sequences by multiple cycles of in vitro selection using infectious viral particles. The selected RNA pool of RSV-binding sequences at a concentration of 0.16 microM completely neutralized the virus. Of 19 sequences cloned from the selected pool, 5 inhibited RSV infection. The selected RNA and RNA analogs were shown to neutralize RSV by interacting with the virus, rather than by adversely affecting the host cells. The selection of the anti-RSV RNA and RNA analogs by intact virions immediately suggests the potential application of this approach to develop RNA and RNA analogs as inhibitors of other viruses such as human immunodeficiency virus.

Expression of kappa opioid receptors in human and monkey lymphocytes

mRNA encoding the kappa opioid receptor gene sequence was identified and isolated from various human lymphocytic cells: CEM x174 (a hybrid of T and B origin) cells, Jurkat-T4 cells, human peripheral blood mononuclear cells (PBMC) and purified CD4+ cells. Analyzing the cDNA sequences of RNA transcripts spanning the putative second extracellular loop, which has reported dynorphin specificity, and the seventh transmembrane domain revealed a 100% and 95% homology in amino acid sequence to corresponding kappa opioid receptor sequences in human placenta and rat brain, respectively. Expression of a similar kappa opioid receptor sequence could be detected in normal monkey PBMC but not in monkey PBMC in which the CD4+/CD8+ cell ratio (or CD4+ cell number) was significantly reduced due to prolonged SIV infection. These findings suggest that human and monkey lymphocytes constitutively express kappa opioid receptor mRNA.

Creation of a high cytotoxic active human tumor necrosis factor having the truncated and more basic amino terminus

In order to define the structure-functional relationship of tumor necrosis factor(TNF), a mutant TNF gene was created by site-specific mutagenesis based on the PCR technique. This gene was highly expressed in E.coli cells. The amount of the recombinant protein was up to about 80% of the total cellular proteins. Through one-step ion exchange chromatography, the mutant TNF could be purified to homogeneity. This mutein showed the molecular weight of a dimer but not a trimer. It bears the features of truncated amino terminus and increase of the basicity of amino terminal residues. Compared with the wild type TNF, the specific activity of mutant TNF was increased by fourfold.

Modified RNA sequence pools for in vitro selection

We report the use of modified RNA, in which the 2'-OH group of pyrimidines is replaced by a 2'-amino (2'-NH2) group to identify high affinity ligands specific for human neutrophil elastase (HNE) by in vitro selection. Compared to unmodified RNA the 2'-NH2-modified RNA ligands show enhanced stability in human serum and urine. Use of RNase T1 cleavage data in the presence of K+ and Li+ ions suggests that the modified RNA ligands selected for HNE form an intermolecular G-quartet structure.

Mutagenic effects of heavy ion radiation in plants

Genetic and developmental effects of heavy ions in maize and rice were investigated. Heavy particles with various charges and energies were accelerated at the BEVALAC. The frequency of occurrence of white-yellow stripes on leaves of plants developed from irradiated maize seeds increased linearly with dose, and high-LET heavy charged particles, e.g., neon, argon, and iron, were 2-12 times as effective as gamma rays in inducing this type of mutation. The effectiveness of high-LET heavy ion in (1) inhibiting rice seedling growth, (2) reducing plant fertility, (3) inducing chromosome aberration and micronuclei in root tip cells and pollen mother cells of the first generation plants developed from exposed seeds, and (4) inducing mutation in the second generation, were greater than that of low-LET gamma rays. All effects observed were dose-dependent; however, there appeared to be an optimal range of doses for inducing certain types of mutation, for example, for argon ions (400 MeV/u) at 90-100 Gy, several valuable mutant lines with favorable characters, such as semidwarf, early maturity and high yield ability, were obtained. Experimental results suggest that the potential application of heavy ions in crop improvement is promising. RFLP analysis of two semidwarf mutants induced by argon particles revealed that large DNA alterations might be involved in these mutants.

Detection of c-erbB-2 activation in paraffin-embedded tissue by immunohistochemistry

Commercially available monoclonal antibodies were tested for their ability to detect increased levels of c-erbB-2 protein in formalin-fixed, paraffin-embedded breast carcinomas. Of five antibodies studied, four (TAB-250, CB11, 3B5, and N3/D10) showed strong cytoplasmic membrane reactivity in 23% (11 of 47) of routinely processed tumors, although interpretation of the immunoreactivity with 3B5 and N3/D10 occasionally was difficult due to cytoplasmic granular staining. Since the c-erbB-2 oncogene is activated by DNA amplification and overexpression of mRNA and protein, the same tumors were analyzed for c-erbB-2 activation by other techniques. c-erbB-2 activation in these 11 tumors was confirmed by immunohistochemistry of frozen tissue (nine of nine tumors), in situ hybridization (nine of 11 tumors), and Southern blot analysis (five of eight tumors). In some of these tumors the failure to demonstrate c-erbB-2 DNA amplification may be due to the small percentage of malignant cells. One additional tumor showed probable c-erbB-2 protein overproduction based on strong immunoreactivity with two antibodies (TAB-250 and CB11), although no definite activation could be demonstrated by additional techniques. Three other tumors (6%) showed equivocal c-erbB-2 protein overproduction based on weak immunoreactivity only with TAB-250, although unequivocal activation could not be demonstrated by additional techniques. The 32 carcinomas (68%) that showed no significant immunoreactivity with any antibodies in routinely processed tissue also showed no detectable c-erbB-2 activation by additional techniques. We conclude that TAB-250 and CB11 are reliable antibodies for detecting c-erbB-2 protein overproduction in routinely processed tissue. TAB-250 also weakly stains a few tumors showing no definite c-erbB-2 activation by other techniques. Two additional antibodies (3B5 and N3/D10) detect c-erbB-2 protein overproduction in paraffin-embedded tissue, but are more difficult to interpret. A fifth antibody, TA-1, is an excellent reagent for use on frozen tissue, but prolonged formalin fixation may impair recognition of its antigenic epitope.

[COMVp regimen in the treatment of small cell lung cancer--report of 106 patients]

One hundred and six consecutive small cell lung cancer patients were treated by a combination regimen COMVp (CTX 1,000-1,400 mg IV D 1,8; VCR 1-2 mg IV D 1,8; MTX 20-40 mg IV or IM D 3,5,10,12; VP-16 100 mg IV drip D 3-7; three weeks as a cycle and 2-3 cycles as a course) in our hospital during 1983 to 1984. Among the 95 patients who were evaluated, 10 (10.5%) gave CR, 57 (60%) PR, 19 (20%) no change and 9 (9.5%) progression. The overall response rate was 70.5%. In this paper, factors influencing the response and side effects are also analysed. The data show that COMVp regimen is one of the good front line combination chemotherapy regimens currently available in the management of small cell lung cancer.

Thyrotropin enzyme-immunoassay in dried blood spots: a spectrophotometric method for neonatal thyroid screening

We describe an enzyme-immunoassay with photometric endpoint determination, suitable for the measurement of thyrotropin (TSH) in dried blood spotted on filter paper. Using reagents of a commercially available test kit provided for the measurement of thyrotropin in 200 microliter serum, we have adapted the method to the determination of thyrotropin in blood spots containing ca. 10 microliter blood. This was achieved by prolongation of the assay time from 3 to 20 hours, and by increasing the amount of enzyme-antibody complex. Precision and sensitivity of the blood spot assay are comparable to those of our in-house thyrotropin RIA, and the RIA/EIA correlation coefficient is 0.987 (n = 150). The advantages of EIA are the simplicity of the photometric end point determination (although strict time control has to be observed in order to avoid drifts in results), the long stability of reagents, and the non-isotopic label. The method therefore appears to be a suitable alternative to thyrotropin RIA for the determination of thyrotropin in neonatal thyroid screening.