Publications by authors named "Klaus Steube"

For many years, immortalized cell lines have been used as model systems for cancer research. Cell line panels were established for basic research and drug development, but did not cover the full spectrum of leukemia and lymphoma. Therefore, we now developed a novel panel (LL-100), 100 cell lines covering 22 entities of human leukemia and lymphoma including T-cell, B-cell and myeloid malignancies.

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Eight intestinal cell lines, established from different animal species were submitted to DSMZ (German Collection of Microorganisms and Cell Cultures) in order to analyze their species of origin and their microbial contamination. Species identity was determined by PCR targeting mitochondrial genes and hence confirmed by sequencing the amplified PCR products. For three cell lines (CIEB, CLAB, PSI-1) we confirmed the species identity, whereas the species of origin of the three other cell lines (B6, B10XI and IPEC) was not the expected one: B6 and B10XI cells, which were supposed to be of chicken origin were identified as porcine cells.

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The high prevalence of contaminated cell cultures suggests that viral contaminations might be distributed among cultures. We investigated more than 460 primate cell lines for Epstein-Barr (EBV), hepatitis B (HBV), hepatitis C (HCV), human immunodeficiency virus type 1 (HIV-1), human T-cell leukemia/lymphoma virus I and II (HTLV-I/-II), and squirrel monkey retrovirus (SMRV) infections for risk assessment. None of the cell lines were infected with HCV, HIV-1, or HTLV-I/-II.

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Background: The pTalpha/preTCR regulates the beta-selection, a crucial T-cell developmental checkpoint, providing a most potent survival advantage to thymocytes mediated by the src-kinase p56(Lck).

Methods: To define the relevance of pTalpha in human T-cell lymphoblastic leukemia (T-ALL), we analyzed in T-ALL cell lines (n=14) pTalpha and p56(Lck) mRNA and protein expression as also the tyrosine-phosphorylation. The p56(Lck) specific src-protein-tyrosine kinase inhibitor (PTK-I) PP1 was used in growth inhibition assays.

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Cell lines represent valuable tools for basic research and diagnostic applications as well as for the production of biological products such as antibodies or vaccines. For all cell culturists, a well-identified origin of their cell lines as well as the periodic re-examination of their identity should be a basic requirement. We established a simple polymerase chain reaction (PCR) to verify or identify rodent and human cell lines.

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The ethyl acetate extract of Penicillium sp., derived from the Mediterranean sponge Axinella verrucosa, yielded the known compound communesin B (1) and its new congeners communesins C (2) and D (3), as well as the known compounds griseofulvin, dechlorogriseofulvin, and oxaline. All structures were unambiguously established by 1D and 2D NMR and MS data.

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Continuous cell lines are widely used in cell biology and serve as model systems in basic and applied research. Fundamental requirements for the use of cell lines are a well-identified origin and the exclusion of cross-contamination by prokaryotic or eukaryotic cells. Because the cross-contamination of one cell line with another cell line may occur in a concealed manner, special emphasis must be taken to (1) prevent such an "accident" and (2) monitor regularly the identity of the cell line(s) in use.

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The protein kinase inhibitor staurosporine elicits multiple responses in various systems. We evaluated nine naturally occurring staurosporine derivatives as modulators of chemokine production by monitoring the secretion of interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) in the cell line NB-4. Several staurosporines increased, dose- and time-dependently, the IL-8 and MCP-1 concentration in the cell culture supernatants and three derivatives strongly inhibited proliferation of the NB-4 cells.

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Thirteen new metabolites, melophlins C-O (1-13), were identified from the marine sponge Melophlus sarassinorum. Compounds 1-13 represent tetramic acid derivatives that differ with regard to the nature of their alkyl side chains. The structures of the new compounds were elucidated on the basis of comprehensive spectral analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as low- and high-resolution ESIMS and EIMS).

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Analysis of the Papua New Guinean sponge Theonella swinhoei afforded a new calyculinamide-related congener for which we propose the name swinhoeiamide A (1). The structure of the new compound was unambiguously established on the basis of NMR spectroscopic ((1)H, (13)C, COSY, HMBC) and mass spectrometric (FABMS) data. Swinhoeiamide A exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated in an artificial diet offered to the larvae in a chronic feeding bioassay (ED(50) 2.

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