Enhanced subtilisin production with spore mutants of Bacillus subtilis and their characterization.
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Bacillus subtilis↗
Biomedical subjects
B G Kim
Publications and source records attributed to B G Kim.
Loss of heterozygosity on the short arm of chromosome 17 in uterine cervical carcinomas.
DNA samples from 26 cervical carcinoma and normal tissue pairs were studied by restriction fragment length polymorphism (RFLP) analysis to determine the frequency of loss of heterozygosity (LOH) on 17p. Allelic loss in the p13.1 region of chromosome 17, known to contain the TP53 locus, was not detected in any of 10 informative cases. Instead, LOH was detected on 17p13.3 in eight (40%) of 20 informative cases with at least one of two 17p13.3 markers. Examination of the intragenic region of p53 in the same samples using polymerase chain reaction (PCR)-RFLP analysis showed no LOH in the gene (none of 16 informative individuals).
Base Sequence↗
p53 mutation in epithelial ovarian carcinoma and borderline ovarian tumor.
We have investigated a series of 19 human ovarian carcinomas and 17 borderline ovarian tumors to determine the loss of heterozygosity on chromosome 17p and possible concurrent p53 mutations. Allelic losses were assessed using restriction fragment length polymorphism study, and p53 gene mutations were detected by single strand conformation polymorphism analysis and by direct sequencing. In addition, we stained the same tumor sections immunohistochemically to detect p53 protein in tissues. Among 19 ovarian malignant tumor samples tested, we identified 17p allelic deletions in 12 (63.2%) of 19 informative cases. The p53 gene mutation was observed in 7 of 19 (36.8%) malignant ovarian tumors, and it was predominantly observed in tumors with allelic loss on 17p (six of seven tumors, 85.7%). Although 9 cases of 17 borderline ovarian tumors showed shifted bands on single strand conformation polymorphism analysis, only one case was proved to have a point mutation in direct sequencing. We also obtained six cases (31.6%) of positive immunoreactivity from 19 ovarian cancers and 3 cases (17.6%) from 17 borderline ovarian tumors. We conclude that loss or inactivation of tumor suppressor gene function by chromosome 17p allelic deletions or p53 mutations are important genetic changes in ovarian cancer.
Adenofibroma↗
Stage IIb cervical carcinoma: MR evaluation of effect of intraarterial chemotherapy.
PURPOSE: To evaluate magnetic resonance (MR) imaging in assessment of tumor response after intraarterial chemotherapy (IAC) in cervical carcinoma. MATERIALS AND METHODS: MR images of 19 patients who underwent IAC because of stage IIb cervical carcinoma were prospectively analyzed and compared with pathologic findings. Three courses of IAC were administered, and MR images were obtained before and after treatment. Extent of reduction of tumor volume determined eligibility for surgery. MR images of 17 patients who were candidates for surgery were correlated with pathologic specimens. RESULTS: Average reduction in tumor volume was 88.5%. Response to IAC was complete in seven patients, partial in 11, and minor in one. MR imaging findings after IAC correlated well with pathologic findings. CONCLUSION: MR imaging is useful in assessment of tumor response to IAC and provides criteria for decision making with regard to further radiation or surgical therapy.
Adult↗
Isolation and characterization of phosphorylated bovine prolactin.
Quantitative isolation of bovine prolactin was accomplished by immunoaffinity chromatography using clonal antibody as the stationary ligand. The phosphorylated and non-phosphorylated (native) prolactins contained in the immunopurified preparations were separated by chromatofocusing. Isolates from individual pituitaries revealed that phosphorylated prolactin represented between 20 and 80% of the total prolactin. The stoichiometry of phosphate in phosphorylated prolactin was 1.4:1 when determined by amino acid analysis after preparation of the S-ethylcysteine derivative. One major phosphorylation site, serine-90, and two minor sites, serine-26 and -34, were determined by mapping and sequencing studies. Serine-90 was conserved in prolactins, growth hormones and placental lactogens. Serine-26 and -34 were conserved in prolactins, but were not found in growth hormones or placental lactogens. Absorption spectroscopy of the aromatic amino acid residues indicated that phosphorylation of prolactin was associated with a unique structural conformation.
Amino Acid Sequence↗
Phosphorylated variant of bovine prolactin.
Bovine pituitary explants and cell cultures were incubated with [32P]orthophosphate. Extracts were prepared from the explants and analyzed by sodium dodecyl sulfate-containing acrylamide gel electrophoresis and autoradiography revealing a phosphoprotein that co-migrated with authentic bovine prolactin. Clonal antibodies to bovine prolactin were produced, purified and used to prepare affinity columns. Extracts of [32P]orthophosphate-labeled explants and cells or media were applied to prolactin affinity columns and a radiolabeled protein was eluted with a pH 2.8 wash. The eluted protein was identified as prolactin by co-migration with standard on gel electrophoresis and by amino acid analysis. Treatment of immunoaffinity-purified pituitary prolactin with alkaline phosphatase reduced the phosphate associated with prolactin in a time-dependent manner, indicating a covalent phosphate linkage. Autoradiography of gels revealed prolactin from explants, cells and their associated media to be a phosphoprotein. A phosphorylated variant of bovine prolactin is synthesized and secreted in both explant and cell cultures.
Animals↗
Inhibition of multiplication in Acanthamoeba castellanii by specific inhibitors of ornithine decarboxylase.
Proliferation of Acanthamoeba castellanii (Neff strain) in either a broth medium or a defined medium was arrested by alpha-monofluoromethyldehydroornithine (delta-MFMOme), alpha-difluoromethylornithine (DFMO), and (R,R')-delta-methyl-alpha-acetylenic putrescine (MAP), three specific inhibitors of ornithine decarboxylase. Although all three inhibited the ameba enzyme, delta-MFMOme was the most effective inhibitor of multiplication. Growth inhibition was reversed by the addition of polyamines. The inhibitors did not induce differentiation by themselves although DFMO caused encystment when supplemented with CaCl2 or MgSO4.
Acanthamoeba↗
Polyamine metabolism in Acanthamoeba: polyamine content and synthesis of ornithine, putrescine, and diaminopropane.
Five polyamines which could be separated by high performance liquid chromatography were found in Acanthamoeba castellanii (strain Neff). These included in order of decreasing abundance: 1,3-diaminopropane, spermidine, spermine, norspermidine, and putrescine. Only diaminopropane and norspermidine had been found previously. Spermine was present in cultures grown in broth, but not in defined medium. Radioactive substrates were used to establish that putrescine was synthesized by decarboxylation of ornithine, ornithine was synthesized from arginine or citrulline, and diaminopropane was synthesized from spermidine. The presence of ornithine decarboxylase (EC 4.1.1.17), arginase (EC 3.5.3.1), and urease (EC 3.5.1.5) and the absence of arginine decarboxylase (EC 4.1.1.19) were established. A scheme for polyamine biosynthesis in A. castellanii is proposed.
Acanthamoeba↗
Growth behavior and prediction of copy number and retention of ColE1-type plasmids in E. coli under slow growth conditions.
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Biotechnology↗
Kinetic resolution of racemic alpha-methyl-beta-propiothiolactone by lipase-catalyzed hydrolysis.
Kinetic resolution of racemic alpha-methyl-beta-propiothiolactone (rac-MPTL) using lipases in organic solvent was studied. The lipase from Pseudomonas cepacia (PCL) showed the highest (S)-enantioselectivity (E > 100), and cyclohexane containing 1% (v/v) buffer was identified as the best reaction medium for maintaining high enantioselectivity as well as high reaction rate. While the substrate inhibition was not observed up to 300 mM rac-MPTL, severe product inhibition was observed even at 50 mM racemic 3-mercapto-alpha-methyl propionic acid (rac-MMPA), which made the use of high substrate concentration difficult. To overcome the product inhibition, the products, (R)-MMPA, were neutralized by addition of a dilute basic solution. Although the resolution reaction proceeded further by the base titration, the enantioselectivity of the reaction decreased as a result of nonenantioselective hydrolysis of rac-MPTL in the basic solution. Under these conditions, 200 mM rac-MPTL was successfully resolved to above 95% ee(S) with 53% conversion.
Burkholderia cepacia↗
Molecular aspects of the cell cycle and encystment of Acanthamoeba.
Evidence for subdivision of the cell cycle of Acanthamoeba into ultradian biochemical cycles is accumulating, and a linkage between these cycles and the length of the cell cycle is possible. The DNA replication cycle differs with the method of assay: no G1 phase is found in asynchronous cultures, and a long G1 phase is found in synchronous cultures. Encystment most likely occurs from G2, but whether it is limited to a portion of this phase is not clear. Encystment-enhancing factors are released by Acanthamoeba castellanii and Acanthamoeba palestinensis, and encystment can be induced by monoclonal antibodies to plasma membrane proteins. Likewise, encystment can be induced by inhibitors of polyamine synthesis, especially diamidines that inhibit S-adenosylmethionine decarboxylase, but inhibition of this enzyme is not necessarily responsible for differentiation. Studies on the regulation of gene expression during encystment have focused on actin and the ribosomal RNA transcriptional unit.
Acanthamoeba↗
Successful management with glue injection of arterial rupture seen during embolization of an arteriovenous malformation using a flow-directed catheter: a case report.
We present a case in which an arterial rupture occurring during embolization of an arteriovenous malformation of the left occipital lobe with a flow-directed microcatheter, was successfully sealed with a small amount of glue. We navigated a 1.8-Fr Magic catheter through the posterior cerebral artery, and during superselective test injection, extravasation was observed at the parieto-occipital branch. The catheter was not removed and the perforation site was successfully sealed with a small amount of glue injected through the same catheter. Prompt recognition and closure of the perforation site is essential for good prognosis.
Adult↗