Establishment and characterization of a lymphoepithelial-like carcinoma cell line (HUUCLEC) derived from the human uterine cervix

A cell line designated HUUCLEC was established from a human uterine cervical lymphoepithelial carcinoma obtained from a 61-year-old Japanese woman. The cell line has grown slowly without interruption and serial passages were successively carried out 60 times within 3 years. The cultured cells were spindle or round in shape, showing anaplastic and pleomorphic features, a pavement cell arrangement and multilayering without contact inhibition. The population doubling time of the HUUCLEC line was 72 hours while the chromosomal number varied widely and showed aneuploidy. The modal chromosomal number was stable at the triploid range and marker chromosomes were present; the Ebstein-Barr virus was absent in the cultured cells.     

Purification and characterization of a lipase from the glycolipid-producing yeast Kurtzmanomyces sp. I-11

An extracellular lipase produced by the glycolipid-producing yeast Kurtzmanomyces sp. I-11 was purified by ammonium sulfate precipitation and column chromatographies on DEAE-Sephadex A-25, SP-Sephadex C-50, and Sephadex G-100. Based on the analysis of the purified lipase on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified lipase was judged to be homogeneous and its molecular mass was estimated to be approximately 49 kDa. The optimum temperature for the activity was 75 degrees C, and the activity was very stable at temperatures below 70 degrees C. The active pH range of this lipase was 1.9-7.2, and the activity was stable at pH below 7.1. The lipase showed a preference for C18 acyl groups by measurements with p-nitrophenyl esters and triglycerides as substrates. The lipase was very stable in the presence of various organic solvents at a concentration of 40%. Although the N-terminal sequence of the Kurtzmanomyces lipase was very similar to that of lipase A from Candida antarctica, the pH profiles of the two lipases were significantly different.     

Preparation of poly(L-lactide)-based microspheres having a cationic or anionic surface using biodegradable surfactants

Poly(L-lactide)-based microspheres having cationic or anionic surfaces were prepared using polydepsipeptide-block-poly(L-lactide)s as surfactants. Polydepsipeptide-block-poly(L-lactide)s having amino or carboxylic acid groups on their side chains were synthesized through anionic ring-opening polymerizations of L-lactide using the corresponding protected polydepsipeptides as macroinitiators and consequent deprotections. Since these amphiphilic copolymers consisting of hydrophobic segments and hydrophilic segments with amino or carboxylic acid groups could be converted to cationic or anionic block copolymers, they could act as surfactants preparing poly(L-lactide)-based microspheres by an oil-in-water emulsion method. The amount of ionic groups located on the surfaces of the obtained microspheres was found to increase with increasing the feed of charged polydepsipeptide-block-poly(L-lactide)s in the blend of poly(L-lactide) and block copolymers. The average diameters of the dried microspheres estimated by scanning electron microscopy were found to decrease with an increase in feed of block copolymers in polymer blends.     

X-ray snapshots of quinone cofactor biogenesis in bacterial copper amine oxidase

The quinone cofactor TPQ in copper amine oxidase is generated by posttranslational modification of an active site tyrosine residue. Using X-ray crystallography, we have probed the copper-dependent autooxidation process of TPQ in the enzyme from Arthrobacter globiformis. Apo enzyme crystals were anaerobically soaked with copper; the structure determined from this crystal provides a view of the initial state: the unmodified tyrosine coordinated to the bound copper. Exposure of the copper-bound crystals to oxygen led to the formation of freeze-trapped intermediates; structural analyses indicate that these intermediates contain dihydroxyphenylalanine quinone and trihydroxyphenylalanine. These are the first visualized intermediates during TPQ biogenesis in copper amine oxidase.     

Spectroelectrochemical evaluation of redox potentials of cysteine tryptophylquinone and two hemes c in quinohemoprotein amine dehydrogenase from Paracoccus denitrificans

Quinohemoprotein amine dehydrogenase (QH-AmDH) from Paracoccus denitrificans has a novel cofactor cysteine tryptophylquinone (CTQ) in the smallest gamma subunit and two hemes c in the largest alpha subunit [Datta, S., Mori, Y., Takagi, K., Kawaguchi, K., Chen, Z., Okajima, T., Kuroda, S., Ikeda, T., Kano, K., Tanizawa, K., and Mathews, F. S. (2001) Proc. Natl. Acad. Sci. U.S.A. 98, 14268-14273]. The spectral change of QH-AmDH was assigned to the redox reaction of the hemes c alone. The redox potentials of the two hemes c with His and Met as the second axial ligands, respectively, were determined to be 0.149 and 0.235 V versus SHE at pH 7.0 by a mediator-assisted continuous-flow column electrolytic spectroelectrochemistry (MCES). The monomeric gamma subunit of QH-AmDH was isolated from urea-treated QH-AmDH. The fully oxidized and reduced forms of the gamma subunit exhibited a unique absorption band centered at 380 nm and a shoulder band around 315 nm, respectively, at neutral pH. The two-electron redox potential of CTQ in the isolated gamma subunit was evaluated to be 65 mV at pH 7.0 by MCES. The redox reaction was linked to the two-proton transfer at pH <8.6 and to a single-proton transfer at pH >8.6. The pK(a) value (K(a) being the acid dissociation constant) of 8.6 was assigned to one of the phenolic OH groups of the quinol form. Upon deprotonation, the red shift of the shoulder band was observed. The gamma subunit adsorbed on a glassy carbon electrode, and gave a direct but quasi-reversible electrochemical signal. Intra- and interprotein electron transfers of QH-AmDH are discussed from thermodynamic and structural points of view.     

Cloning and characterization of two extracellular heparin-degrading endosulfatases in mice and humans

Here we report the cloning of a full-length cDNA encoding the human ortholog (HSulf-1) of the developmentally regulated putative sulfatases QSulf-1 (Dhoot, G. K., Gustafsson, M. K., Ai, X., Sun, W., Standiford, D. M., and Emerson, C. P., Jr. (2001) Science 293, 1663-1666) and RSulfFP1 (Ohto, T., Uchida, H., Yamazaki, H., Keino-Masu, K., Matsui, A., and Masu, M. (2002) Genes Cells 7, 173-185) as well as a cDNA encoding a closely related protein, designated HSulf-2. We have also obtained cDNAs for the mouse orthologs of both Sulfs. We demonstrate that the proteins encoded by both classes of cDNAs are endoproteolytically processed in the secretory pathway and are released into conditioned medium of transfected CHO cells. We demonstrate that the mammalian Sulfs exhibit arylsulfatase activity with a pH optimum in the neutral range; moreover, they can remove sulfate from the C-6 position of glucosamine within specific subregions of intact heparin. Taken together, our results establish that the mammalian Sulfs are extracellular endosulfatases with strong potential for modulating the interactions of heparan sulfate proteoglycans in the extracellular microenvironment.     

Similarity of tetracycline resistance genes isolated from fish farm bacteria to those from clinical isolates

Tetracycline-resistant (Tet(r)) bacteria were isolated from fishes collected at three different fish farms in the southern part of Japan in August and September 2000. Of the 66 Tet(r) gram-negative strains, 29 were identified as carrying tetB only. Four carried tetY, and another four carried tetD. Three strains carried tetC, two strains carried tetB and tetY, and one strain carried tetC and tetG. Sequence analyses indicated the identity in Tet(r) genes between the fish farm bacteria and clinical bacteria: 99.3 to 99.9% for tetB, 98.2 to 100% for tetC, 99.7 to 100% for tetD, 92.0 to 96.2% for tetG, and 97.1 to 100% for tetY. Eleven of the Tet(r) strains transferred Tet(r) genes by conjugation to Escherichia coli HB-101. All transconjugants were resistant to tetracycline, oxycycline, doxycycline, and minocycline. The donors included strains of Photobacterium, Vibrio, Pseudomonas, Alteromonas, Citrobacter, and Salmonella spp., and they transferred tetB, tetY, or tetD to the recipients. Because NaCl enhanced their growth, these Tet(r) strains, except for the Pseudomonas, Citrobacter, and Salmonella strains, were recognized as marine bacteria. Our results suggest that tet genes from fish farm bacteria have the same origins as those from clinical strains.     

Simple non-ion-paired high-performance liquid chromatographic method for simultaneous quantitation of carboxylate and lactone forms of 14 new camptothecin derivatives

SN-38 (7-ethyl-10-hydroxycamptothecin) is an active metabolite derived from the semi-synthetic compound camptothecin (CPT) named Irinotecan (CPT-11). The antitumor activity of SN-38 is 1000-fold more potent than the parent CPT-11. Fourteen new derivatives of camptothecin have recently been developed by Yakult Honsha (Tokyo, Japan). Here we describe a simple and cost-effective high-performance liquid chromatography (HPLC) method without an ion-pairing agent, which allows the simultaneous determination of both lactone and carboxylate forms of SN-38 and other camptothecin derivatives. A weak linear relationship between the HPLC retention factors (ln k') and the cellular concentrations of these compounds was observed. These results suggest that low-polarity compounds easily accumulate in cancer cells and may circumvent drug resistance. The HPLC analysis herein described is expected to greatly assist in derivative synthesis and chemical modification of camptothecin-based antitumor drugs.