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Schlatter S, Bailey JE, Fussenegger M. Novel surface tagging technology for selection of complex proliferation-controlled mammalian cell phenotypes. Biotechnol Bioeng 2001; 75:597-606. [PMID: 11745136 DOI: 10.1002/bit.1189] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Regulated overexpression of the cyclin dependent kinase inhibitor p27 enables biphasic production processes which consist of a nonproducing expansion phase followed by an extended proliferation-arrested production phase. During the growth-arrested production phase proliferation-competent mutants emerge as a consequence of genetic drift and strong counterselection. Here, we evaluate the use of cell surface markers for ex vivo selection of growth-arrested phenotypes by magnetic or FACS-mediated cell sorting. Multigene metabolic engineering resulted in a Chinese hamster ovary- (CHO) derived cell line CHO-SS101(5), which expresses the model product protein SEAP (secreted alkaline phosphatase), the human cyclindependent kinase inhibitor p27, and a membrane-anchored multidomain surface marker Hook in a tricistronic tetracycline-repressible manner. In the absence of tetracycline in the cell culture medium, p27 mediated a G1-phase-specific cell-cycle arrest of CHO-SS101(5) and resulted in a fivefold increase in SEAP production compared to proliferation-competent control cells. Concomitant expression of Hook enabled FACS- or magnetic-based selection of CHO-SS101(5) cells from various mixed populations. Surface selection of engineered cells will likely become important for biopharmaceutical manufacturing and for in vivo maintenance of treated cells in gene therapy and tissue engineering.
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Knudson MD, Hanson DL, Bailey JE, Hall CA, Asay JR, Anderson WW. Equation of state measurements in liquid deuterium to 70 GPa. PHYSICAL REVIEW LETTERS 2001; 87:225501. [PMID: 11736405 DOI: 10.1103/physrevlett.87.225501] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Indexed: 05/23/2023]
Abstract
Using intense magnetic pressure, a method was developed to launch flyer plates to velocities in excess of 20 km/s. This technique was used to perform plate-impact, shock wave experiments on cryogenic liquid deuterium ( L-D(2)) to examine its high-pressure equation of state. Using an impedance matching method, Hugoniot measurements were obtained in the pressure range of 30-70 GPa. The results of these experiments disagree with previously reported Hugoniot measurements of L-D(2) in the pressure range above approximately 40 GPa, but are in good agreement with first principles, ab initio models for hydrogen and its isotopes.
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Moser S, Rimann M, Fux C, Schlatter S, Bailey JE, Fussenegger M. Dual-regulated expression technology: a new era in the adjustment of heterologous gene expression in mammalian cells. J Gene Med 2001; 3:529-49. [PMID: 11778900 DOI: 10.1002/jgm.219] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND On the basis of the compatible streptogramin- and tetracycline-responsive expression systems, a series of dual-regulated expression systems have been established for use in sophisticated biopharmaceutical manufacturing, advanced gene therapy, and tissue engineering. METHODS Dual-regulated expression concepts enable streptogramin- and tetracycline-responsive control of two different (sets of) transgenes (multi-regulated multigene metabolic engineering), dual-autoregulated expression configurations for one-step chromosomal integration of two antibiotic-adjustable expression units, and artificial regulatory cascades for multi-level regulation of transgenes and optimized integration of molecular interventions into mammalian regulatory networks. RESULTS This report describes the construction and testing of a family of dual-regulated expression vectors which are compatible with the pTRIDENT vector construction kit, and, in some cases, adapted for retroviral expression technology enabling straightforward transduction of difficult-to-transfect cell lines such as primary cells and stem cells. CONCLUSIONS Dual-regulated expression technology will probably become of prime interest for a variety of therapeutic applications, including biopharmaceutical manufacturing, gene therapy, and tissue engineering.
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Dätwyler DA, Magyar JP, Busceti V, Hirschy A, Perriard JC, Bailey JE, Eppenberger HM. Recombinant Sindbis virus allows expression and precise targeting of proteins of the contractile apparatus in cultured cardiomyocytes. Basic Res Cardiol 2001; 96:630-5. [PMID: 11770082 DOI: 10.1007/s003950170015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Expression of epitope-tagged sarcomeric proteins in cardiomyocytes is a powerful approach for the characterization of interacting domains. Here, we report a new strategy for the study of the targeting of contractile proteins in cardiomyocytes by Sindbis virus (SIN)-mediated gene transfer. Two recombinant SIN were generated, one encoding the myosin-light chain MLC3f-eGFP fusion protein (SINrep5/MLC3f-eGFP), and the other encoding the alpha-actinin-DsRed fusion protein (SINrep5/alpha-actinin-DsRed). After infection of long-term cultured neonatal and adult rat cardiomyocytes with SINrep5/MLC3f-eGFP, the exogenous MLC3f-eGFP fusion protein localized to the sarcomeres. Freshly isolated rod-shaped ventricular cardiomyocytes infected with SINrep5/alpha-actinin-DsRed exhibited a correct incorporation of the newly synthesized alpha-actinin-DsRed fusion protein at the Z-band of the sarcomere. This allows the assumption that the exogenous protein is assembled into myofibrils in living cardiomyocy-tes using the same molecular interactions equally to the endogenous counterpart. It has been thus demonstrated that the SIN expression system makes possible the straightforward analysis of the localization of sarcomeric proteins in cultured cardiomyocytes and may offer new possibilities for the characterization of mutant proteins involved in hypertrophic cardiomyopathies.
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Bailey JE, Womeodu RJ, Wan JY, Van Brunt DL, Somes GW. Improvements in diabetes management and outcomes in a Medicaid managed care system. TENNESSEE MEDICINE : JOURNAL OF THE TENNESSEE MEDICAL ASSOCIATION 2001; 94:425-30. [PMID: 11709896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
OBJECTIVE To determine the impact of managed care on effectiveness of diabetes management in Tennessee, where a statewide Medicaid program (TennCare) delivers services through capitated managed care organizations (MCOs). RESEARCH DESIGN AND METHODS This retrospective cohort study documented the health care utilization experiences and clinical outcomes of a convenience sample of Tennessee Medicaid enrollees with chronic diabetes before and after the initiation of TennCare. Exposures to recommended diabetic services and outcomes were compared before and after TennCare for 171 enrollees with diabetes in the state's largest academic MCO who met age, continuous enrollment, insurance, and diagnostic criteria for two years before (1992 and 1993) and two years after TennCare (1995 and 1996). Claims data were used to assess baseline characteristics and chart review data were used to assess health services utilization for 71% of cohort members (n = 121) for whom complete medical records were available. The paired t-test was used to compare exposures and outcomes before and after TennCare. RESULTS Participants had an average of 6.4 outpatient clinic visits per year before TennCare vs. 8.2 visits per year after TennCare (P = .0009), 0.6 vs. 1.0 diabetic eye examinations (P = .0042), 0.2 vs. 0.5 foot examinations (P = .0358), 0.4 vs. 0.6 cholesterol assessments (P < .0001), and 0.5 vs. 1.0 glycosylated hemoglobin assessments annually (P < .0001). Average glycosylated hemoglobin decreased from 10.3 to 8.2 (P < .0001). Although hospitalizations and hospital days increased overall, there was no increase in emergency visits, preventable emergency visits, or preventable hospitalizations. CONCLUSIONS Enrollees with diabetes experienced increases in utilization of recommended health services and improved glucose control following the initiation of Medicaid managed care. These improvements may reflect improved chronic disease care in a primary care gatekeeper system.
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Cakar ZP, Sauer U, Bailey JE, Müller M, Stolz M, Wallimann T, Schlattner U. Vacuolar morphology and cell cycle distribution are modified by leucine limitation in auxotrophic Saccharomyces cerevisiae. Biol Cell 2001; 92:629-37. [PMID: 11374441 DOI: 10.1016/s0248-4900(01)01111-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Yeast vacuoles are highly dynamic and flexible organelles. In a previous paper, we have shown that subtle, often unrecognised amino acid limitations lead to much lower final cell densities in cultures of different commonly used auxotrophic Saccharomyces cerevisiae strains (Cakar et al., Biotechnol. Lett. 21 (1999) 611). Here, we demonstrate for two of these strains, CEN.PK 113.6B and CBS7752, that such subtle leucine limitations also affect the number and morphology of vacuoles, and that these changes are correlated with the cell cycle in batch cultures in a similar way as is known from synchronized cultures. Morphological aspects were studied by electron microscopy, using advanced high pressure freezing/freeze-substitution techniques for sample preparation that so far have been barely successful in yeast. Cells of leucine-limited cultures had single, large vacuoles with a hexagonal tonoplast pattern and were partially arrested in G1 phase. To relieve leucine-limitation, additional leucine was supplied extracellularly via the medium or intracellularly via enhanced leucine biosynthesis due to plasmid-based expression of a leucine marker gene. Such cultures reached more than two-fold higher final optical densities in stationary phase. Cells in later growth phase were characterized by fragmented vacuoles lacking any tonoplast pattern and by a smaller proportion of cells in G1 phase. These drastic effects of subtle leucine limitation on cell physiology, vacuolar morphology and cell cycle distribution present a note of caution for morphological and cell cycle studies in yeast.
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Holmberg N, Farrés J, Bailey JE, Kallio PT. Targeted expression of a synthetic codon optimized gene, encoding the spruce budworm antifreeze protein, leads to accumulation of antifreeze activity in the apoplasts of transgenic tobacco. Gene 2001; 275:115-24. [PMID: 11574159 DOI: 10.1016/s0378-1119(01)00635-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A synthetic gene based on the primary sequence of the mature spruce budworm antifreeze protein (sbwAFP) was constructed by primer overlap extension. The amino acid codons were chosen to mimic those of a highly expressed tobacco nuclear gene. A DNA sequence encoding the amino-terminal leader sequence from the tobacco pathogen related protein 1b (PR), which targets the protein to the apoplastic space, was fused in frame to the synthetic sbwAFP gene. This fusion was placed downstream of the cauliflower mosaic virus 35S promoter and upstream of the nopaline synthase terminator in a T-DNA binary vector. Transgenic tobacco lines transcribing PR-sbwAFP were selected by RT-PCR. The apoplastic protein fractions of sbwAFP expressing tobacco lines exhibited enhanced antifreeze activity as demonstrated by the ability to inhibit ice re-crystallization and increased thermal hysteresis.
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Dauner M, Bailey JE, Sauer U. Metabolic flux analysis with a comprehensive isotopomer model in Bacillus subtilis. Biotechnol Bioeng 2001; 76:144-56. [PMID: 11505384 DOI: 10.1002/bit.1154] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Fluxes in central carbon metabolism of a genetically engineered, riboflavin-producing Bacillus subtilis strain were investigated in glucose-limited chemostat cultures at low (0.11 h(-1)) and high (0.44 h(-1)) dilution rates. Using a mixture of 10% [U-(13)C] and 90% glucose labeled at natural abundance, (13)C-labeling experiments were carried out to provide additional information for metabolic flux balancing. The resulting labeling pattern in the proteinogenic amino acids were analyzed by two-dimensional [(13)C, (1)H] nuclear magnetic resonance (NMR) spectroscopy. To account rigorously for all available data from these experiments, we developed a comprehensive isotopomer model of B. subtilis central metabolism. Using this model, intracellular carbon net and exchange fluxes were estimated on the basis of validated physiological data and biomass composition in combination with 2D NMR data from 45 individual carbon atom spectra in the amino acids. Glucose catabolism proceeded primarily via glycolysis but pentose phosphate pathway fluxes increased with increasing growth rate. Moreover, significant back fluxes from the TCA cycle to the lower part of glycolysis via the gluconeogenic PEP carboxykinase were detected. The malic enzyme reaction, in contrast, was found to be inactive. A thorough statistical analysis was performed to prove the reliability of the isotopomer balance model and the obtained results. Specifically, a chi(2) test was applied to validate the model and the chi-square criterion was used to explore the sensitivity of model predictions to the experimental data.
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Brünke P, Sterner O, Bailey JE, Minas W. Heterologous expression of the naphthocyclinone hydroxylase gene from Streptomyces arenae for production of novel hybrid polyketides. Antonie Van Leeuwenhoek 2001; 79:235-45. [PMID: 11816965 DOI: 10.1023/a:1012037329949] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Streptomyces arenae produces at least four different isochromanequinone antibiotics, the naphthocyclinones, of which the beta- and gamma-form are active against Gram-positive bacteria. The naphthocyclinone biosynthesis gene cluster was isolated from Streptomyces arenae DSM 40737 and by sequence analysis the minimal polyketide synthase genes and several genes encoding tailoring enzymes were identified. Southern blot analysis of the naphthocyclinone gene cluster indicated that a 3.5 kb BamHI fragment located approximately 9 kb downstream of the minimal PKS genes hybridizes to the schC hydroxylase DNA probe isolated from S. halstedii. Two complete and one incomplete open reading frames were identified on this fragment. Sequence analysis revealed strong homology to the genes of the actVA region of S. coelicolor, to several (suggested) hydroxylases and a putative FMN-dependent monooxygenase. The proposed hydroxylase, encoded by ncnH, could hydroxylate aloesaponarin II, a molecule that is produced by the actinorhodin minimal polyketide synthase in combination with the actinorhodin ketoreductase, aromatase and cyclase. Furthermore, this enzyme is capable of accepting additional polyketide core structures that contain a 5-hydroxy-1,4-naphthoquinone moiety as substrates which makes it an interesting tailoring enzyme for the modification of polyketide structures.
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Bollinger CJ, Bailey JE, Kallio PT. Novel hemoglobins to enhance microaerobic growth and substrate utilization in Escherichia coli. Biotechnol Prog 2001; 17:798-808. [PMID: 11587567 DOI: 10.1021/bp010091j] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Limited oxygen availability is a prevalent problem in microbial biotechnology. Recombinant Escherichia coli expressing the hemoglobin from Vitreoscilla (VHb) or the flavohemoglobin from Ralstonia eutropha (formerly Alcaligenes eutrophus) (FHP) demonstrate significantly increased cell growth and productivity under microaerobic conditions. We identify novel bacterial hemoglobin-like proteins and examine if these novel bacterial hemoglobins can elicit positive effects similar to VHb and FHP and if these hemoglobins alleviate oxygen limitation under microaerobic conditions when expressed in E. coli. Several finished and unfinished bacterial genomes were screened using R. eutropha FHP as a query sequence for genes (hmp) encoding hemoglobin-like proteins. Novel hmp genes were identified in Pseudomonas aeruginosa, Salmonella typhi, Klebsiella pneumoniae, Deinococcus radiodurans, and Campylobacter jejuni. Previously characterized hmp genes from E. coli and Bacillus subtilis and the novel hmp genes from P. aeruginosa, S. typhi, C. jejuni, K. pneumoniae, and D. radiodurans were PCR amplified and introduced into a plasmid for expression in E. coli. Biochemically active hemoproteins were expressed in all constructs, as judged by the ability to abduct carbon monoxide. Growth behavior and byproduct formation of E. coli K-12 MG1655 cells expressing various hemoglobins were analyzed in microaerobic fed-batch cultivations and compared to plasmid-bearing control and to E. coli cells expressing VHb. The clones expressing hemoglobins from E. coli, D. radiodurans, P.aeruginosa, and S. typhi reached approximately 10%, 27%, 23%, and 36% higher final optical density values, respectively, relative to the plasmid bearing E. coli control (A(600) 5.5). E. coli cells expressing hemoproteins from P. aeruginosa, S. typhi, and D. radiodurans grew to similar final cell densities as did the strain expressing VHb (A(600) 7.5), although none of the novel constructs was able to outgrow the VHb-expressing E. coli strain. Additionally, increased yield of biomass on glucose was measured for all recombinant strains, and an approximately 2-fold yield enhancement was obtained with D. radiodurans hemoprotein-expressing E. coli relative to the E. coli control carrying the parental plasmid without any hemoglobin gene.
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Koller D, Ruedl C, Loetscher M, Vlach J, Oehen S, Oertle K, Schirinzi M, Deneuve E, Moser R, Kopf M, Bailey JE, Renner W, Bachmann MF. A high-throughput alphavirus-based expression cloning system for mammalian cells. Nat Biotechnol 2001; 19:851-5. [PMID: 11533644 DOI: 10.1038/nbt0901-851] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have developed a widely applicable functional genomics strategy based on alphavirus expression vectors. The technology allows for rapid identification of genes encoding a functional activity such as binding of a defined ligand. Complementary DNA (cDNA) libraries were expressed in mammalian cells following infection with recombinant Sindbis virus (SIN replicon particles), a member of the Alphavirus genus. Virus-infected cells that specifically bound a ligand of choice were isolated using fluorescence-activated cell sorting (FACS). Replication-competent, infective SIN replicon particles harboring the corresponding cDNA were amplified in a next step. Within one round of selection, viral clones encoding proteins recognized by monoclonal antibodies or Fc-fusion molecules could be isolated and sequenced. Moreover, using the same viral libraries, a plaque-lift assay was established that allowed the identification of secreted, intracellular, and membrane proteins.
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Kaufmann H, Marone R, Olayioye MA, Bailey JE, Fussenegger M. Characterization of an N-terminally truncated cyclin A isoform in mammalian cells. J Biol Chem 2001; 276:29987-93. [PMID: 11402021 DOI: 10.1074/jbc.m005452200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cyclin A is essential for regulating key transitions in the eukaryotic cell cycle including initiation of DNA replication and mitosis. This paper describes the characterization of a truncated cyclin A isoform (cyclin A(t)) in vitro in cultured mammalian cells and in mouse tissues. The presence of cyclin A(t) in specific cell types correlates with the ability of cell extracts to cleave in vitro translated cyclin A. In CHO-K1 cells, cyclin A processing to cyclin A(t) occurs at the N terminus; it does not involve the 26 S proteasome, nor could it be induced by conditional overexpression of the cyclin-dependent kinase inhibitor p27(Kip1). However, high cell densities lead to increased cyclin A(t) levels. Unlike full-length cyclin A, cyclin A(t) localizes to the cytoplasm, where it binds Cdk2. The data suggest that cyclin A processing occurs in vivo to yield an N-terminally truncated isoform by an unknown mechanism that is regulated by cell density. Differential subcellular localization may provide the first insights into the physiological role of cyclin A(t).
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Frey AD, Rimann M, Bailey JE, Kallio PT, Thompson CJ, Fussenegger M. Novel pristinamycin-responsive expression systems for plant cells. Biotechnol Bioeng 2001; 74:154-63. [PMID: 11370004 DOI: 10.1002/bit.1105] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Novel gene regulation systems were designed for plant cells responsive to the streptogramin antibiotic pristinamycin. The pristinamycin-repressible plant gene regulation concept (PIPpOFF) is based on a transcriptional activator (PIT) which consists of the Pip protein, the repressor of the pristinamycin resistance operon of Streptomyces coelicolor, fused to the VP16 transactivation domain of the Herpes simplex virus. PIT mediates pristinamycin-repressible activation of a synthetic plant promoter (P(pPIR)) in tobacco cells consisting of a nine Pip-binding site-containing artificial operator (PIR3) placed upstream of a TATA-box derived from the cauliflower mosaic virus 35S promoter (P(CaMV35S)). Pristinamycin interferes with induction by negatively regulating the DNA-binding capacity of the Pip moiety of PIT. A second, streptogramin-inducible plant gene regulation system (PIPpON) was constructed by combining Pip expression with a plant-specific pristinamycin-inducible promoter (P(pPIRON)). P(pPIRON) consists of a PIR3 module cloned downstream of the strong constitutive plant promoter P(CaMV35S). As in the native Streptomyces configuration, Pip binds to its cognate sequence within P(pPIRON) in the absence of regulating antibiotic and silences the chimeric plant promoter. Upon addition of pristinamycin, Pip is released from the PIR3 operator and full P(CaMV35S)-driven expression of desired plant genes is induced. The PIPpOFF and PIPpON systems performed well in Nicotiana tabacum suspension cultures and promise to provide an attractive extension of existing plant gene regulation technology for basic plant research or biopharmaceutical manufacturing using plant tissue culture.
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Wilson SJ, Bailey JE, Alford C, Nutt DJ. Sleep and daytime sleepiness the next day following single night-time dose of fluvoxamine, dothiepin and placebo in normal volunteers. J Psychopharmacol 2001; 14:378-86. [PMID: 11198056 DOI: 10.1177/026988110001400420] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
To explore the effects of sedating and non-sedating antidepressants, we conducted a placebo-controlled, double-blind cross-over study in 12 normal subjects of the effects of a single night-time dose of fluvoxamine 100 mg, dothiepin 100 mg or placebo on night-time sleep recorded at home, and sleepiness and performance the following day. Night-time sleep was altered significantly by both drugs, with main effects on rapid eye movement (REM) sleep and sleep continuity. Dothiepin increased total sleep time, REM latency and stage 2 sleep and decreased arousals, wake after sleep onset and stage 1, whereas fluvoxamine decreased total sleep time and REM time and increased wake after sleep onset. Sleep latencies in daytime naps were significantly shorter for dothiepin and longer for fluvoxamine, showing that subjects were more sleepy when taking dothiepin. Electroencephalograms (EEG) performed during performance tasks failed to distinguish significantly between drugs. There were no significant differences between groups on our measures of tracking performance or reaction time; however, these tasks were designed primarily to provide a standard setting in which to monitor continuous EEG, and were unsuitable to detect sleepiness effects themselves. Saccadic eye movement velocity, acceleration and deceleration showed small non-significant changes after both drugs. Mood self ratings showed no significant differences among the groups. Subjective measures of night-time sleep reflected the objective measures of sleep continuity, and the items for difficulty and speed of wakening in the morning were significantly higher (i.e. more difficulty and slower) in the dothiepin group. The home-recorded sleep findings after fluvoxamine in this study were very similar to sleep laboratory studies with other antidepressant drugs, thus providing more validation of the home recording method.
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Bailey JE, Heard D, Schumacher J, Bennett A, Pablo LS. Midazolam/butorphanol/ketamine and the clinically effective dose of isoflurane anesthesia of ostriches (Struthio camelus). Vet Anaesth Analg 2001; 28:109. [PMID: 28404343 DOI: 10.1111/j.1467-2987.2001.40-28.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Randall-Schadel BL, Bailey JE, Beute MK. Seed Transmission of Cylindrocladium parasiticum in Peanut. PLANT DISEASE 2001; 85:362-370. [PMID: 30831967 DOI: 10.1094/pdis.2001.85.4.362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Seedborne Cylindrocladium parasiticum has been reported in peanuts and the possibility of seed transmission postulated; however, seed transmission has not been documented. Cinnamon brown speckles on peanut testae were correlated with isolation of C. parasiticum. Microscopy indicated that seed were colonized by cinnamon brown colored hyphae and microsclerotia interspersed in and on lightened areas of testa. Speckled seed from commercial seed lots (cultivars NC 7, NC 10C) were planted, with or without a chemical seed treatment (1992, captan + carboxin + dicloran [45:18:15% of product]; 1993 to 1995, captan + PCNB + carboxin [45:15:10% of product]), in fumigated fields with no history of peanut production. Asymptomatic seed from noninfested seed lots (cultivar NC-V 11 or NC 7) were checks for soilborne inoculum. C. parasiticum was isolated from all symptomatic seed lots prior to planting (percentage ranged from 4 to 45%) but was not isolated from asymptomatic seed. Seed transmission occurred from seed both with chemical seed treatment (0.25 to 2.75%) and without seed treatment (0.25 to 6.0%), but not in all years. Asymptomatic seed planted 2.5 cm from speckled seed increased the number of plants with Cylindrocladium black rot from two- to sixfold, illustrating the ability of disease to spread from colonized seed to uninfected plants. It was concluded that seed transmission of C. parasiticum is an important means by which this disease is spread within the seed industry.
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Bailey JE, Foerster SH, Foerster CR. Evaluation of oscillometric blood pressure monitoring during immobilization of free-ranging Baird's tapirs (Tapirus bairdii) in Costa Rica. Vet Anaesth Analg 2001; 28:108. [DOI: 10.1111/j.1467-2987.2001.40-26.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bailey JE. Reflections on the scope and the future of metabolic engineering and its connections to functional genomics and drug discovery. Metab Eng 2001; 3:111-4. [PMID: 11289787 DOI: 10.1006/mben.2001.0184] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Concepts, experience, and tools from metabolic engineering are immediately applicable to the challenge of understanding how the genome influences phenotype. However, new experimental approaches and mathematical and computational resources are needed to maximize the contributions of metabolic engineering to general questions in functional genomics. Among the priorities are systems for studying physiology on a microscale, theoretical tools for understanding biological control systems, and metabolic simulators "in silico" which provide reasonable predictions of stimulus-response relationships at engineering and medical resolution, with incomplete information on cellular mechanisms and their parameters. Approaching cells as complex systems, already a well-established principle in metabolic engineering, is essential to surmount stagnation in the rate of pharmaceutical discovery which is still based on a naive single-target paradigm.
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Maaheimo H, Fiaux J, Cakar ZP, Bailey JE, Sauer U, Szyperski T. Central carbon metabolism of Saccharomyces cerevisiae explored by biosynthetic fractional (13)C labeling of common amino acids. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:2464-79. [PMID: 11298766 DOI: 10.1046/j.1432-1327.2001.02126.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Aerobic and anaerobic central metabolism of Saccharomyces cerevisiae cells was explored in batch cultures on a minimal medium containing glucose as the sole carbon source, using biosynthetic fractional (13)C labeling of proteinogenic amino acids. This allowed, firstly, unravelling of the network of active central pathways in cytosol and mitochondria, secondly, determination of flux ratios characterizing glycolysis, pentose phosphate cycle, tricarboxylic acid cycle and C1-metabolism, and thirdly, assessment of intercompartmental transport fluxes of pyruvate, acetyl-CoA, oxaloacetate and glycine. The data also revealed that alanine aminotransferase is located in the mitochondria, and that amino acids are synthesized according to documented pathways. In both the aerobic and the anaerobic regime: (a) the mitochondrial glycine cleavage pathway is active, and efflux of glycine into the cytosol is observed; (b) the pentose phosphate pathways serve for biosynthesis only, i.e. phosphoenolpyruvate is entirely generated via glycolysis; (c) the majority of the cytosolic oxaloacetate is synthesized via anaplerotic carboxylation of pyruvate; (d) the malic enzyme plays a key role for mitochondrial pyruvate metabolism; (e) the transfer of oxaloacetate from the cytosol to the mitochondria is largely unidirectional, and the activity of the malate-aspartate shuttle and the succinate-fumarate carrier is low; (e) a large fraction of the mitochondrial pyruvate is imported from the cytosol; and (f) the glyoxylate cycle is inactive. In the aerobic regime, 75% of mitochondrial oxaloacetate arises from anaplerotic carboxylation of pyruvate, while in the anaerobic regime, the tricarboxylic acid cycle is operating in a branched fashion to fulfill biosynthetic demands only. The present study shows that fractional (13)C labeling of amino acids represents a powerful approach to study compartmented eukaryotic systems.
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Kaufmann H, Mazur X, Marone R, Bailey JE, Fussenegger M. Comparative analysis of two controlled proliferation strategies regarding product quality, influence on tetracycline-regulated gene expression, and productivity. Biotechnol Bioeng 2001; 72:592-602. [PMID: 11460250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Overexpression of the cyclin-dependent kinase inhibitor p27 and exposure to low temperature (30 degrees C) represent two strategies to establish controlled proliferation processes for production of therapeutic proteins using Chinese hamster ovary (CHO) cells. Here we analyze the effect of growth inhibition on the quality of the human model glycoprotein SEAP (secreted alkaline phosphatase) for both strategies in monoclonal CHO-derived cell lines. Separation of purified SEAP samples using two-dimensional gel electrophoresis showed that production by proliferation-controlled CHO cultures did not alter the overall integrity of the product. Further, oligosaccharide profiles were compared using HPEC-PAD analysis. No differences were detectable between SEAP profiles obtained from p27 growth-arrested and proliferating cultures. However, production at 30 degrees C led to a significant increase in the degree of sialylation, an effect that is generally considered beneficial for the in vivo efficacy of protein therapeutics. In the production context presented here, SEAP expression is controlled by the tetracycline- (tet) repressible gene regulation system. Here we show low temperature-induced upregulation of the tetracycline-dependent transactivator (tTA). This induction has been shown by Northern blot analysis to occur at the mRNA level and is independent of the promoters driving the transactivator. We also describe a novel bottleneck in productivity at low temperature found in p27 growth-arrested CHO cells cultivated at 30 degrees C.
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Fux C, Moser S, Schlatter S, Rimann M, Bailey JE, Fussenegger M. Streptogramin- and tetracycline-responsive dual regulated expression of p27(Kip1) sense and antisense enables positive and negative growth control of Chinese hamster ovary cells. Nucleic Acids Res 2001; 29:E19. [PMID: 11160939 PMCID: PMC29626 DOI: 10.1093/nar/29.4.e19] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2000] [Revised: 12/22/2000] [Accepted: 12/22/2000] [Indexed: 12/26/2022] Open
Abstract
We constructed a dual regulated expression vector cassette (pDuoRex) whereby two heterologous genes can be independently regulated via streptogramin- and tetracycline-responsive promoters. Two different constructs containing growth-promoting and growth-inhibiting genes were stably transfected in recombinant Chinese hamster ovary (CHO) cells that express the streptogramin- and tetracycline-dependent transactivators in a dicistronic configuration. An optimally balanced heterologous growth control scenario was achieved by reciprocal expression of the growth-inhibiting human cyclin-dependent kinase inhibitor p27(Kip1) in sense (p27(Kip1)S) and antisense (p27(Kip1)AS) orientation. Exclusive expression of p27(Kip1)S resulted in complete G(1)-phase-specific growth arrest, while expression of only p27(Kip1)AS showed significantly increased proliferation compared to control cultures (both antibiotics present), presumably by decreasing host cell p27(Kip1) expression. In a second system, a derivative of pDuoRex encoding streptogramin-responsive expression of the growth-promoting SV40 small T antigen (sT) and tetracycline-regulated expression of p27(Kip1) was stably transfected into CHO cells. Expression of sT alone resulted in an increase in cell proliferation, but the expression of p27(Kip1) failed to provide the expected G(1)-specific growth arrest despite having demonstrated expression of the protein. This illustrates the difficulty in balancing the complex pathways underlying cell proliferation control through the expression of two functionally distinct genes involved in those pathways, and how a single-gene sense/antisense approach using pDuoRex can overcome this barrier to complete metabolic engineering control.
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Frey AD, Fiaux J, Szyperski T, Wüthrich K, Bailey JE, Kallio PT. Dissection of central carbon metabolism of hemoglobin-expressing Escherichia coli by 13C nuclear magnetic resonance flux distribution analysis in microaerobic bioprocesses. Appl Environ Microbiol 2001; 67:680-7. [PMID: 11157231 PMCID: PMC92635 DOI: 10.1128/aem.67.2.680-687.2001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2000] [Accepted: 11/29/2000] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli MG1655 cells expressing Vitreoscilla hemoglobin (VHb), Alcaligenes eutrophus flavohemoprotein (FHP), the N-terminal hemoglobin domain of FHP (FHPg), and a fusion protein which comprises VHb and the A. eutrophus C-terminal reductase domain (VHb-Red) were grown in a microaerobic bioreactor to study the effects of low oxygen concentrations on the central carbon metabolism, using fractional (13)C-labeling of the proteinogenic amino acids and two-dimensional [(13)C, (1)H]-correlation nuclear magnetic resonance (NMR) spectroscopy. The NMR data revealed differences in the intracellular carbon fluxes between E. coli cells expressing either VHb or VHb-Red and cells expressing A. eutrophus FHP or the truncated heme domain (FHPg). E. coli MG1655 cells expressing either VHb or VHb-Red were found to function with a branched tricarboxylic acid (TCA) cycle. Furthermore, cellular demands for ATP and reduction equivalents in VHb- and VHb-Red-expressing cells were met by an increased flux through glycolysis. In contrast, in E. coli cells expressing A. eutrophus hemeproteins, the TCA cycle is running cyclically, indicating a shift towards a more aerobic regulation. Consistently, E. coli cells displaying FHP and FHPg activity showed lower production of the typical anaerobic by-products formate, acetate, and D-lactate. The implications of these observations for biotechnological applications are discussed.
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Kaufmann H, Bailey JE, Fussenegger M. Use of antibodies for detection of phosphorylated proteins separated by two-dimensional gel electrophoresis. Proteomics 2001; 1:194-9. [PMID: 11680866 DOI: 10.1002/1615-9861(200102)1:2<194::aid-prot194>3.0.co;2-k] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Protein phosphorylation and dephosphorylation are key regulatory mechanisms in prokaryotic and eukaryotic cells. Considering the role of phosphorylation in many human diseases, it appears a major challenge to refine on the methods to analyze the phospho-proteome. Here we review the use of monoclonal antibodies directed against specific phosphorylated amino acid residues to visualize phosphoproteins separated by two-dimensional gel electrophoresis. Strategies are described how this method can successfully be applied to create phospho-proteome maps of mammalian cells.
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Martin R, Sterner O, Alvarez MA, de Clercq E, Bailey JE, Minas W. Collinone, a New Recombinant Angular Polyketide Antibiotic Made by an Engineered Streptomyces Strain. J Antibiot (Tokyo) 2001; 54:239-49. [PMID: 11372781 DOI: 10.7164/antibiotics.54.239] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Large chromosomal DNA fragments containing different parts of the putative rubromycin polyketide synthase gene cluster were cloned and functionally expressed in S. coelicolor CH999. Expression of these clones yielded 5 approximately 10 metabolites that were not detected in S. collinus culture extracts. This paper focusses on one of the new metabolites, termed collinone, that was isolated in large quantities and purified for spectroscopic structure determination and biological screening assays. Collinone is a heavily oxidized angular hexacyclic compound containing an unusual 1,4,5,8(2H,3H)-anthracenetetrone moiety previously only reported to be present in antibiotics SF2446A1, A2, A3, B1 and B2 isolated from Streptomyces sp. SF2446. Structure analysis of collinone indicates a tridecaketide with a 26 carbon backbone. The basic benz[a]naphthacene ring system of collinone is angular, similar to the aglycones of the well-known angucycline and angucyclinone antibiotics. While collinone showed antibacterial activity against vancomycin-resistant enterococci, no antifungal or significant antiviral activities were detected. Collinone could be a good starting point to obtain new bioactive angucyclin(on)e-like compounds by further genetic engineering of its pathway.
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