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Johanna I, Daudeij A, Devina F, Nijenhuis C, Nuijen B, Romberg B, de Haar C, Haanen J, Dolstra H, Bremer E, Sebestyen Z, Straetemans T, Jedema I, Kuball J. Basics of advanced therapy medicinal product development in academic pharma and the role of a GMP simulation unit. Immunooncol Technol 2023; 20:100411. [PMID: 38192616 PMCID: PMC10772236 DOI: 10.1016/j.iotech.2023.100411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Following successes of authorized chimeric antigen receptor T-cell products being commercially marketed in the United States and European Union, product development of T-cell-based cancer immunotherapy consisting of cell-based advanced therapy medicinal products (ATMPs) has gained further momentum. Due to their complex characteristics, pharmacological properties of living cell products are, in contrast to classical biological drugs such as small molecules, more difficult to define. Despite the availability of many new advanced technologies that facilitate ATMP manufacturing, translation from research-grade to clinical-grade manufacturing in accordance with Good Manufacturing Practices (cGMP) needs a thorough product development process in order to maintain the same product characteristics and activity of the therapeutic product after full-scale clinical GMP production as originally developed within a research setting. The same holds true for transferring a fully developed GMP-grade production process between different GMP facilities. Such product development from the research to GMP-grade manufacturing and technology transfer processes of established GMP-compliant procedures between facilities are challenging. In this review, we highlight some of the main obstacles related to the product development, manufacturing process, and product analysis, as well as how these hinder rapid access to ATMPs. We elaborate on the role of academia, also referred to as 'academic pharma', and the added value of GMP production and GMP simulation facilities to keep innovation moving by reducing the development time and to keep final production costs reasonable.
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Affiliation(s)
- I. Johanna
- Department of Hematology, University Medical Center Utrecht, Utrecht
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht
| | - A. Daudeij
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht
| | - F. Devina
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht
| | - C. Nijenhuis
- Department of Pharmacy & Pharmacology, Netherlands Cancer Institute, Amsterdam
| | - B. Nuijen
- Department of Pharmacy & Pharmacology, Netherlands Cancer Institute, Amsterdam
| | - B. Romberg
- Department of Pharmacy, University Medical Center Utrecht, Utrecht
| | - C. de Haar
- Department of Pharmacy, University Medical Center Utrecht, Utrecht
| | - J. Haanen
- Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam
- Division of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam
| | - H. Dolstra
- Laboratory of Hematology, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen
| | - E. Bremer
- Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Z. Sebestyen
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht
| | - T. Straetemans
- Department of Hematology, University Medical Center Utrecht, Utrecht
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht
| | - I. Jedema
- Division of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam
| | - J. Kuball
- Department of Hematology, University Medical Center Utrecht, Utrecht
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht
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Bremer E, Moreales K, Vargas I, Grandner M, Ellis J, Perlis M. 0415 Does Time In Bed Vary with the Use of Hypnotics? Sleep 2018. [DOI: 10.1093/sleep/zsy061.414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- E Bremer
- Sleep Center, School of Nursing, Emory University, Atlanta, GA
| | - K Moreales
- Department of Biostatistics, University of Pennsylvania, Philadelphia, PA
| | - I Vargas
- Behavioral Sleep Medicine Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA
| | - M Grandner
- Sleep and Health Reserach Program, College of Medicine, University of Arizona, Tucson, AZ
| | - J Ellis
- Northumbria Center for Sleep Research, Northumbria University, New Castle, UNITED KINGDOM
| | - M Perlis
- Behavioral Sleep Medicine Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA
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SAINI P, Bremer E, Broyles S, Rye D, Trotti L. 0617 Working Memory and Psychomotor Vigilance Performance After Brief Naps in Hypersomnolent Patients: MSLT Correlates. Sleep 2018. [DOI: 10.1093/sleep/zsy061.616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- P SAINI
- EMORY UNIVERSITY, ATLANTA, GA
| | | | | | - D Rye
- EMORY UNIVERSITY, ATLANTA, GA
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Hendriks D, Choi G, de Bruyn M, Wiersma VR, Bremer E. Antibody-Based Cancer Therapy: Successful Agents and Novel Approaches. Int Rev Cell Mol Biol 2017; 331:289-383. [PMID: 28325214 DOI: 10.1016/bs.ircmb.2016.10.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Since their discovery, antibodies have been viewed as ideal candidates or "magic bullets" for use in targeted therapy in the fields of cancer, autoimmunity, and chronic inflammatory disorders. A wave of antibody-dedicated research followed, which resulted in the clinical approval of a first generation of monoclonal antibodies for cancer therapy such as rituximab (1997) and cetuximab (2004), and infliximab (2002) for the treatment of autoimmune diseases. More recently, the development of antibodies that prevent checkpoint-mediated inhibition of T cell responses invigorated the field of cancer immunotherapy. Such antibodies induced unprecedented long-term remissions in patients with advanced stage malignancies, most notably melanoma and lung cancer, that do not respond to conventional therapies. In this review, we will recapitulate the development of antibody-based therapy, and detail recent advances and new functions, particularly in the field of cancer immunotherapy. With the advent of recombinant DNA engineering, a number of rationally designed molecular formats of antibodies and antibody-derived agents have become available, and we will discuss various molecular formats including antibodies with improved effector functions, bispecific antibodies, antibody-drug conjugates, antibody-cytokine fusion proteins, and T cells genetically modified with chimeric antigen receptors. With these exciting advances, new antibody-based treatment options will likely enter clinical practice and pave the way toward more successful control of malignant diseases.
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Affiliation(s)
- D Hendriks
- Department of Surgery, Translational Surgical Oncology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - G Choi
- Department of Hematology, Section Immunohematology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - M de Bruyn
- Department of Obstetrics & Gynecology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - V R Wiersma
- Department of Hematology, Section Immunohematology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands.
| | - E Bremer
- Department of Hematology, Section Immunohematology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands; University of Exeter Medical School, Exeter, UK.
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He Y, Hendriks D, Van Ginkel R, Samplonius D, Bremer E, Helfrich W. Melanoma-directed activation of apoptosis using a novel bispecific antibody directed against MCSP and Death Receptor 5. Eur J Cancer 2016. [DOI: 10.1016/s0959-8049(16)61422-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Miller JJ, Bremer E, Curtis T. Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone. J Environ Qual 2016; 45:1437-44. [PMID: 27380095 DOI: 10.2134/jeq2016.01.0033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding.
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Gooden MJM, Wiersma VR, Boerma A, Leffers N, Boezen HM, ten Hoor KA, Hollema H, Walenkamp AME, Daemen T, Nijman HW, Bremer E. Elevated serum CXCL16 is an independent predictor of poor survival in ovarian cancer and may reflect pro-metastatic ADAM protease activity. Br J Cancer 2014; 110:1535-44. [PMID: 24518602 PMCID: PMC3960624 DOI: 10.1038/bjc.2014.55] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 12/30/2013] [Accepted: 01/08/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND In certain cancers, expression of CXCL16 and its receptor CXCR6 associate with lymphocyte infiltration, possibly aiding anti-tumour immune response. In other cancers, CXCL16 and CXCR6 associate with pro-metastatic activity. In the current study, we aimed to characterise the role of CXCL16, sCXCL16, and CXCR6 in ovarian cancer (OC). METHODS CXCL16/CXCR6 expression was analysed on tissue microarray containing 306 OC patient samples. Pre-treatment serum sCXCL16 was determined in 118 patients using ELISA. In vitro, (primary) OC cells were treated with an ADAM-10/ADAM-17 inhibitor (TAPI-2) and an ADAM-10-specific inhibitor (GI254023x), whereupon CXCL16 levels were evaluated on the cell membrane (immunofluorescent analysis, western blots) and in culture supernatants (ELISA). In addition, cell migration was assessed using scratch assays. RESULTS sCXCL16 independently predicted for poor survival (hazard ratio=2.28, 95% confidence interval=1.29-4.02, P=0.005), whereas neither CXCL16 nor CXCR6 expression correlated with survival. Further, CXCL16/CXCR6 expression and serum sCXCL16 levels did not associate with lymphocyte infiltration. In vitro inhibition of both ADAM-17 and ADAM-10, but especially the latter, decreased CXCL16 membrane shedding and strongly reduced cell migration of A2780 and cultured primary OC-derived malignant cells. CONCLUSIONS High serum sCXCL16 is a prognostic marker for poor survival of OC patients, possibly reflecting ADAM-10 and ADAM-17 pro-metastatic activity. Therefore, serum sCXCL16 levels may be a pseudomarker that identifies patients with highly metastatic tumours.
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Affiliation(s)
- M J M Gooden
- 1] Department of Gynecologic Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands [2] Department of Surgery, Translational Surgical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - V R Wiersma
- Department of Surgery, Translational Surgical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A Boerma
- 1] Department of Gynecologic Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands [2] Department of Microbiology, Molecular Virology Section, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - N Leffers
- Department of Gynecologic Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - H M Boezen
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - K A ten Hoor
- Department of Gynecologic Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - H Hollema
- Department of Pathology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - A M E Walenkamp
- Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - T Daemen
- Department of Microbiology, Molecular Virology Section, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - H W Nijman
- Department of Gynecologic Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - E Bremer
- Department of Surgery, Translational Surgical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Abstract
Glioblastoma (GBM) is a devastating cancer with a median survival of around 15 months. Significant advances in treatment have not been achieved yet, even with a host of new therapeutics under investigation. Therefore, the quest for a cure for GBM remains as intense as ever. Of particular interest for GBM therapy is the selective induction of apoptosis using the pro-apoptotic tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). TRAIL signals apoptosis via its two agonistic receptors TRAIL-R1 and TRAIL-R2. TRAIL is normally present as homotrimeric transmembrane protein, but can also be processed into a soluble trimeric form (sTRAIL). Recombinant sTRAIL has strong tumouricidal activity towards GBM cells, with no or minimal toxicity towards normal human cells. Unfortunately, GBM is a very heterogeneous tumour, with multiple genetically aberrant clones within one tumour. Consequently, any single agent therapy is likely to be not effective enough. However, the anti-GBM activity of TRAIL can be synergistically enhanced by a variety of conventional and novel targeted therapies, making TRAIL an ideal candidate for combinatorial strategies. Here we will, after briefly detailing the biology of TRAIL/TRAIL receptor signalling, focus on the promises and pitfalls of recombinant TRAIL as a therapeutic agent alone and in combinatorial therapeutic approaches for GBM.
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Affiliation(s)
- J M A Kuijlen
- Department of Neurosurgery, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands
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Cate B, de Bruyn M, Wei Y, Bremer E, Helfrich W, Mourabet M, El-Hachem S, Harrison J, Binion D. Targeted Elimination of Leukemia Stem Cells; a New Therapeutic Approach in Hemato-Oncology. Curr Drug Targets 2010; 11:95-110. [DOI: 10.2174/138945010790031063] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 08/24/2009] [Indexed: 11/22/2022]
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10
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Beres BL, Cárcamo HA, Bremer E. Evaluation of alternative planting strategies to reduce wheat stem sawfly (Hymenoptera: Cephidae) damage to spring wheat in the northern Great Plains. J Econ Entomol 2009; 102:2137-2145. [PMID: 20069842 DOI: 10.1603/029.102.0617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Wheat, Triticum aestivum L., producers are often reluctant to use solid-stemmed wheat cultivars resistant to wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), due to concerns regarding yield, efficacy or market opportunities. We evaluated the impact of several planting strategies on wheat yield and quality and wheat stem sawfly infestation at two locations over a three-year period. Experimental units consisted of large plots (50 by 200 m) located on commercial farms adjacent to wheat stem sawfly-infested fields. Compared with a monoculture of a hollow-stemmed cultivar ('AC Barrie'), planting a monoculture of a solid-stemmed cultivar ('AC Eatonia') increased yield by an average of 16% (0.4 mg ha(-1)) and increased the grade of wheat by one unit at the two most heavily infested site-years. Planting a 1:1 blend of AC Eatonia and AC Barrie increased yield by an average of 11%, whereas planting 20- or 40-m plot margins to AC Eatonia increased yield by an average of 8%. High wheat stem sawfly pressure limited the effectiveness of using resistant cultivars in field margins because plants were often infested beyond the plot margin, with uniform infestation down the length of the plots at the two most heavily infested site-years. The effectiveness of AC Eatonia to reduce wheat stem sawfly survivorship was modest in this study, probably due to weather-related factors influencing pith expression and to the high abundance of wheat stem sawfly. Greater benefits from planting field margins to resistant cultivars or planting a blend of resistant and susceptible cultivars might be achievable under lower wheat stem sawfly pressure.
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Affiliation(s)
- B L Beres
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, Canada.
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Abstract
Antibody-based therapeutic approaches are yielding more and more of the promise they have held since the conception of the 'magic bullet' theory by Paul Ehrlich. The beneficial effect of antibody-based therapies is directly related to antibody-dependent functions, such as neutralization and antibody-dependent cellular cytotoxicity, but in many cases also relies on the delivery of toxic compounds to cancerous cells. However, the clinical utility of toxic antibody conjugates can be significantly hampered by side effects. Ideal effector compounds are inactive 'en route', but gain full activity once the antibody conjugate has bound to cancerous cells. Of significant potential in this respect are the pro-apoptotic ligands Tumor Necrosis Factor (TNF), fibroblast-associated cell-surface ligand (FasL) and TNF-related apoptosis-inducing ligand (TRAIL). TNF ligands are normally present as homotrimeric transmembrane proteins, but can also be processed into a soluble trimeric form. Compared to their corresponding transmembrane counterpart, soluble TNF, FasL and TRAIL have a strongly reduced capacity to activate TNF receptor 2, Fas and TRAIL receptor 2. However, all sequence information required for full activation of these receptors is latently retained in these soluble ligands and can be unmasked by oligomerization or cell surface immobilization. The latter provides a clear rationale for the use of these ligands as effectors in antibody-based therapy. The antibody-targeted ligand will be in a relatively inactive soluble form while en route. However, once bound to the targeted cancer cell the soluble TNF ligand fusion proteins will be converted into fully active membrane ligand-like molecules. Here we will, after briefly detailing the biology of TNF, TRAIL and FasL, focus on the promises and pitfalls of targeted TNF ligand fusion proteins in achieving a 'magic bullet' with maximum cancer selective activity and minimal side effects.
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Affiliation(s)
- E Bremer
- Department of Surgery, Surgical Research Laboratories, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Schmidt M, Bremer E, Hasenclever D, Victor A, Gehrmann M, Steiner E, Schiffer IB, Gebhardt S, Lehr HA, Mahlke M, Hermes M, Mustea A, Tanner B, Koelbl H, Pilch H, Hengstler JG. Role of the progesterone receptor for paclitaxel resistance in primary breast cancer. Br J Cancer 2007; 96:241-7. [PMID: 17211474 PMCID: PMC2359989 DOI: 10.1038/sj.bjc.6603538] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Paclitaxel plays an important role in the treatment of primary breast cancer. However, a substantial proportion of patients treated with paclitaxel does not appear to derive any benefit from this therapy. We performed a prospective study using tumour cells isolated from 50 primary breast carcinomas. Sensitivity of primary tumour cells to paclitaxel was determined in a clinically relevant range of concentrations (0.85–27.2 μg ml−1 paclitaxel) using an ATP assay. Chemosensitivity data were used to study a possible association with immunohistochemically determined oestrogen and progesterone receptor (ER and PR) status, as well as histopathological parameters. Progesterone receptor (PR) mRNA expression was also determined by quantitative RT–PCR. We observed a clear association of the PR status with chemosensitivity to paclitaxel. Higher levels of immunohistochemically detected PR expression correlated with decreased chemosensitivity (P=0.008). Similarly, high levels of PR mRNA expression were associated with decreased paclitaxel chemosensitivity (P=0.007). Cells from carcinomas with T-stages 3 and 4 were less sensitive compared to stages 1 and 2 (P=0.013). Multiple regression analysis identified PR receptor status and T-stage as independent predictors of paclitaxel chemosensitivity, whereas the ER, N-stage, grading and age were not influential. In conclusion, in vitro sensitivity to paclitaxel was higher for PR-negative compared with PR-positive breast carcinoma cells. Thus, PR status should be considered as a possible factor of influence when designing new trials and chemotherapy protocols.
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Affiliation(s)
- M Schmidt
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - E Bremer
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - D Hasenclever
- Coordinating Center for Clinical Trials, University of Leipzig, Leipzig, Germany
| | - A Victor
- Institute of Medical Biometry, Epidemiology and Information Science, University of Mainz, Mainz, Germany
| | | | - E Steiner
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - I B Schiffer
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - S Gebhardt
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - H-A Lehr
- Institute of Pathology, Johannes Gutenberg University, Mainz, Germany
| | - M Mahlke
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - M Hermes
- Center for Toxicology, University of Leipzig, Haertelstr. 16-18, 04107 Leipzig, Germany
- Leibniz Research Centre for Working Environment and Human Factors, University of Dortmund, Dortmund, Germany
| | - A Mustea
- Department of Obstetrics and Gynecology, Charite, Berlin, Germany
| | - B Tanner
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - H Koelbl
- Department of Obstetrics & Gynecology, Medical School, University of Mainz, Mainz, Germany
| | - H Pilch
- Department of Obstetrics and Gynecology, University of Leipzig, Philipp-Rosenthal-Str. 55, 04103F Leipzig, Germany
| | - J G Hengstler
- Center for Toxicology, University of Leipzig, Haertelstr. 16-18, 04107 Leipzig, Germany
- Leibniz Research Centre for Working Environment and Human Factors, University of Dortmund, Dortmund, Germany
- E-mail:
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13
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ten Cate B, Samplonius DF, Bijma T, de Leij LFMH, Helfrich W, Bremer E. The histone deacetylase inhibitor valproic acid potently augments gemtuzumab ozogamicin-induced apoptosis in acute myeloid leukemic cells. Leukemia 2006; 21:248-52. [PMID: 17122863 DOI: 10.1038/sj.leu.2404477] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gemtuzumab ozogamicin (GO) is a calicheamicin-conjugated antibody directed against CD33, an antigen highly expressed on acute myeloid leukemic (AML) cells. CD33-specific binding triggers internalization of GO and subsequent hydrolytic release of calicheamicin. Calicheamicin then translocates to the nucleus, intercalates in the DNA structure and subsequently induces double-strand DNA breaks. GO is part of clinical practice for AML, but is frequently associated with severe side effects. Therefore, combination of GO with other therapeutics is warranted to reduce toxicity, while maximizing therapeutic selectivity. We hypothesized that the histone deacetylase inhibitor valproic acid (VPA) sensitizes AML cells to GO. VPA-induced histone hyperacetylation opens the chromatin structure, whereby the DNA intercalation of calicheamicin should be augmented. We found that clinically relevant concentrations of VPA potently augmented the tumoricidal activity of GO towards AML cell lines and primary AML blasts. Moreover, VPA treatment indeed augmented the DNA intercalation of calicheamicin and enhanced DNA degradation. Importantly, synergy was restricted to CD33-positive AML cells and did not require caspase activation. In conclusion, the synergistic proapoptotic activity of cotreatment of AML cells with VPA and GO indicates the potential value of this strategy for AML.
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MESH Headings
- Aminoglycosides/therapeutic use
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized
- Anticonvulsants/toxicity
- Antigens, CD/blood
- Antigens, Differentiation, Myelomonocytic/blood
- Antineoplastic Agents/therapeutic use
- Apoptosis/drug effects
- Cell Line, Tumor
- DNA, Neoplasm/drug effects
- Drug Synergism
- Gemtuzumab
- Histone Deacetylase Inhibitors
- Humans
- Intercalating Agents/pharmacology
- Leukemia, Myeloid, Acute/pathology
- Sialic Acid Binding Ig-like Lectin 3
- U937 Cells
- Valproic Acid/toxicity
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Affiliation(s)
- B ten Cate
- Laboratory for Tumor Immunology, Department of Pathology and Laboratory Medicine, Groningen University Institute for Drug Exploration, Section Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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14
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Albrich SB, Bremer E, Schmidt M, Gehrmann M, Victor A, Hengstler J, Kölbl H. Einfluss von HER-2 und Topoisomerase II-alpha auf die ex vivo Chemosensitivität für Epirubicin beim primären Mammakarzinom. Geburtshilfe Frauenheilkd 2006. [DOI: 10.1055/s-2006-952383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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15
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Schmidt M, Bremer E, Victor A, Gehrmann M, Hengstler JG, Koelbl H. Microtubule-associated protein tau and in vitro paclitaxel sensitivity in primary breast cancer. J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.20088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
20088 Background: Paclitaxel has an important role in the adjuvant therapy of primary breast cancer. Recently, microtubule-associated protein tau was described as a marker of paclitaxel sensitivity. We attempted to validate these findings in vitro utilizing the ATP tumorchemosensitivity assay (ATP-TCA). Methods: The in vitro drug sensitivity to paclitaxel was evaluated in 48 fresh primary breast cancer specimens using the ATP-TCA. ATP-TCA results were analysed using the area under the curve (AUC) of growth inhibition. These results were correlated with the expression of tau mRNA measured by quantitative RT-PCR (Spearman’s correlation coefficient). Tau was also compared between progesterone receptor (PgR) positive and negative and estrogen receptor (ER) positive and negative tumors, respectively (Wilcoxon test). Results: The correlation of tau with the AUC for paclitaxel was weak (r = −0.20) and disappeared when considering PgR positive and negative tumors separately (r = −0.004 and r = −0.048, respectively). Tau was found to be differentially expressed between PgR positive and negative as well as between ER positive and negative tumors (p < 0.0005 in both tests). Conclusions: The expression of tau does not show independent predictive value for the in vitro paclitaxel sensitivity in primary breast cancer. No significant financial relationships to disclose.
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Affiliation(s)
- M. Schmidt
- University Hospital, Mainz, Germany; University of Mainz, Mainz, Germany; Bayer HealthCare AG, Leverkusen, Germany; University of Leipzig, Leipzig, Germany
| | - E. Bremer
- University Hospital, Mainz, Germany; University of Mainz, Mainz, Germany; Bayer HealthCare AG, Leverkusen, Germany; University of Leipzig, Leipzig, Germany
| | - A. Victor
- University Hospital, Mainz, Germany; University of Mainz, Mainz, Germany; Bayer HealthCare AG, Leverkusen, Germany; University of Leipzig, Leipzig, Germany
| | - M. Gehrmann
- University Hospital, Mainz, Germany; University of Mainz, Mainz, Germany; Bayer HealthCare AG, Leverkusen, Germany; University of Leipzig, Leipzig, Germany
| | - J. G. Hengstler
- University Hospital, Mainz, Germany; University of Mainz, Mainz, Germany; Bayer HealthCare AG, Leverkusen, Germany; University of Leipzig, Leipzig, Germany
| | - H. Koelbl
- University Hospital, Mainz, Germany; University of Mainz, Mainz, Germany; Bayer HealthCare AG, Leverkusen, Germany; University of Leipzig, Leipzig, Germany
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16
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Wood JM, Bremer E, Csonka LN, Kraemer R, Poolman B, van der Heide T, Smith LT. Osmosensing and osmoregulatory compatible solute accumulation by bacteria. Comp Biochem Physiol A Mol Integr Physiol 2001; 130:437-60. [PMID: 11913457 DOI: 10.1016/s1095-6433(01)00442-1] [Citation(s) in RCA: 337] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Bacteria inhabit natural and artificial environments with diverse and fluctuating osmolalities, salinities and temperatures. Many maintain cytoplasmic hydration, growth and survival most effectively by accumulating kosmotropic organic solutes (compatible solutes) when medium osmolality is high or temperature is low (above freezing). They release these solutes into their environment when the medium osmolality drops. Solutes accumulate either by synthesis or by transport from the extracellular medium. Responses to growth in high osmolality medium, including biosynthetic accumulation of trehalose, also protect Salmonella typhimurium from heat shock. Osmotically regulated transporters and mechanosensitive channels modulate cytoplasmic solute levels in Bacillus subtilis, Corynebacterium glutamicum, Escherichia coli, Lactobacillus plantarum, Lactococcus lactis, Listeria monocytogenes and Salmonella typhimurium. Each organism harbours multiple osmoregulatory transporters with overlapping substrate specificities. Membrane proteins that can act as both osmosensors and osmoregulatory transporters have been identified (secondary transporters ProP of E. coli and BetP of C. glutamicum as well as ABC transporter OpuA of L. lactis). The molecular bases for the modulation of gene expression and transport activity by temperature and medium osmolality are under intensive investigation with emphasis on the role of the membrane as an antenna for osmo- and/or thermosensors.
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Affiliation(s)
- J M Wood
- Department of Microbiology and Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, University of Guelph, Canada.
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17
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Belitsky BR, Brill J, Bremer E, Sonenshein AL. Multiple genes for the last step of proline biosynthesis in Bacillus subtilis. J Bacteriol 2001; 183:4389-92. [PMID: 11418582 PMCID: PMC95331 DOI: 10.1128/jb.183.14.4389-4392.2001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2001] [Accepted: 04/25/2001] [Indexed: 11/20/2022] Open
Abstract
The complete Bacillus subtilis genome contains four genes (proG, proH, proI, and comER) with the potential to encode Delta(1)-pyrroline-5-carboxylate reductase, a proline biosynthetic enzyme. Simultaneous defects in three of these genes (proG, proH, and proI) were required to confer proline auxotrophy, indicating that the products of these genes are mostly interchangeable with respect to the last step in proline biosynthesis.
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Affiliation(s)
- B R Belitsky
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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18
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Hynes RK, Jans DC, Bremer E, Lupwayi NZ, Rice WA, Clayton GW, Collins MM. Rhizobium population dynamics in the pea rhizosphere of rhizobial inoculant strain applied in different formulations. Can J Microbiol 2001; 47:595-600. [PMID: 11547878 DOI: 10.1139/w01-047] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of inoculant formulation on the population dynamics of rhizobia in the pea rhizosphere was investigated using a streptomycin-resistant mutant of Rhizobium leguminosarum bv. viceae NITRAGIN128C56G (128C56G strR). The isolate was formulated into liquid, peat powder, and granular peat carriers, and was tested on pea at field sites near Saskatoon, Saskatchewan, and Beaverlodge, Alberta, in 1996 and 1997. The liquid and peat powder formulations were applied to seed while the granular inoculant was applied to soil. In three out of four site years, population dynamics were similar among formulations: an initial decline or lag period lasting 2-5 days followed by an increase to approximately 10(5) colony-forming units (CFU)/seedling by 14-28 days after planting (DAP) and, where sampled, a continuing increase from 10(7) to 10(8) CFU/plant at 63 DAP. In these same site years, nodule number (not determined at Beaverlodge in 1997) and nodule occupancy at 60 days were not significantly different among formulations. In contrast, soil populations of 128C56G strR from the liquid formulation declined to near zero by 28 DAP at Beaverlodge in 1996, when soil moisture was excessive in spring because of high rainfall. Populations increased in this treatment after this time, but remained significantly lower than the populations of the other two formulations throughout the sampling period. Pea seed yields were not significantly different among treatments in either year at Beaverlodge, but were significantly higher with granular inoculant than the noninoculated control in Saskatoon. Within inoculated treatments at Saskatoon, there were no significant differences in grain yield.
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Affiliation(s)
- R K Hynes
- Agrium Inc., Ag Biologicals, Saskatoon, SK, Canada.
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19
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Kozlowski DA, Bremer E, Redmond DE, George D, Larson B, Bohn MC. Quantitative analysis of transgene protein, mRNA, and vector DNA following injection of an adenoviral vector harboring glial cell line-derived neurotrophic factor into the primate caudate nucleus. Mol Ther 2001; 3:256-61. [PMID: 11237683 DOI: 10.1006/mthe.2000.0256] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gene therapy for neurodegenerative diseases relies on stable expression of a vector-mediated transgene in the human central nervous system (CNS). In nonhuman primate CNS, transgene expression has been primarily assessed using descriptive histological methods. Here, we quantified the expression of a human glial cell line-derived neurotrophic factor (hGDNF) transgene using an ELISA specific for hGDNF protein and real-time quantitative RT-PCR and PCR for hGDNF mRNA and vector DNA, respectively. Transgene expression was assessed 1 week after injection of an E1-, E3-deleted adenovirus harboring hGDNF into the caudate nucleus of St. Kitts green monkey. We found that 57-147 million and 116-771 million copies of hGDNF mRNA and vector DNA, respectively, were present per 10,000 copies of the beta-actin gene. In the same sites, 40-152 pg of hGDNF protein per milligram of tissue was measured. Comparisons of these measures among monkeys demonstrated variable vector DNA and protein levels, but consistent mRNA levels at one-third of the level of vector DNA. This suggests that local responses to the vector play a role in the level of transgene expression and that high levels of vector DNA do not necessarily predict a high level of transgene protein. However, the results of this study do show that neuroprotective levels of GDNF transgene expression can be achieved following injection of an adenoviral vector into nonhuman primate caudate. Moreover, these assays provide quantitative methods for evaluating and comparing viral vectors in primate CNS.
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Affiliation(s)
- D A Kozlowski
- Children's Memorial Institute for Education and Research, Northwestern University Medical School, Chicago, Illinois 60614, USA
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20
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Bremer E. Coping with osmotic challenges: osmoregulation through accumulation and release of compatible solutes in B. subtilis. Comp Biochem Physiol A Mol Integr Physiol 2000. [DOI: 10.1016/s1095-6433(00)80031-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Kappes RM, Kempf B, Kneip S, Boch J, Gade J, Meier-Wagner J, Bremer E. Two evolutionarily closely related ABC transporters mediate the uptake of choline for synthesis of the osmoprotectant glycine betaine in Bacillus subtilis. Mol Microbiol 1999; 32:203-16. [PMID: 10216873 DOI: 10.1046/j.1365-2958.1999.01354.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Biosynthesis of the compatible solute glycine betaine in Bacillus subtilis confers a considerable degree of osmotic tolerance and proceeds via a two-step oxidation process of choline, with glycine betaine aldehyde as the intermediate. We have exploited the sensitivity of B. subtilis strains defective in glycine betaine production against glycine betaine aldehyde to select for mutants resistant to this toxic intermediate. These strains were also defective in choline uptake, and genetic analysis proved that two mutations affecting different genetic loci (opuB and opuC) were required for these phenotypes. Molecular analysis allowed us to demonstrate that the opuB and opuC operons each encode a binding protein-dependent ABC transport system that consists of four components. The presumed binding proteins of both ABC transporters were shown to be lipoproteins. Kinetic analysis of [14C]-choline uptake via OpuB (K(m) = 1 microM; Vmax = 21 nmol min-1 mg-1 protein) and OpuC (K(m) = 38 microM; Vmax = 75 nmol min-1 mg-1 protein) revealed that each of these ABC transporters exhibits high affinity and substantial transport capacity. Western blotting experiments with a polyclonal antiserum cross-reacting with the presumed substrate-binding proteins from both the OpuB and OpuC transporter suggested that the expression of the opuB and opuC operons is regulated in response to increasing osmolality of the growth medium. Primer extension analysis confirmed the osmotic control of opuB and allowed the identification of the promoter of this operon. The opuB and opuC operons are located close to each other on the B. subtilis chromosome, and their high sequence identity strongly suggests that these systems have evolved from a duplication event of a primordial gene cluster. Despite the close relatedness of OpuB and OpuC, these systems exhibit a striking difference in substrate specificity for osmoprotectants that would not have been predicted readily for such closely related ABC transporters.
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Affiliation(s)
- R M Kappes
- Philipps University Marburg, Department of Biology, Germany
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22
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Nau-Wagner G, Boch J, Le Good JA, Bremer E. High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis. Appl Environ Microbiol 1999; 65:560-8. [PMID: 9925583 PMCID: PMC91062 DOI: 10.1128/aem.65.2.560-568.1999] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/1998] [Accepted: 11/10/1998] [Indexed: 11/20/2022] Open
Abstract
We report here that the naturally occurring choline ester choline-O-sulfate serves as an effective compatible solute for Bacillus subtilis, and we have identified a high-affinity ATP-binding cassette (ABC) transport system responsible for its uptake. The osmoprotective effect of this trimethylammonium compound closely matches that of the potent and widely employed osmoprotectant glycine betaine. Growth experiments with a set of B. subtilis strains carrying defined mutations in the glycine betaine uptake systems OpuA, OpuC, and OpuD and in the high-affinity choline transporter OpuB revealed that choline-O-sulfate was specifically acquired from the environment via OpuC. Competition experiments demonstrated that choline-O-sulfate functioned as an effective competitive inhibitor for OpuC-mediated glycine betaine uptake, with a Ki of approximately 4 microM. Uptake studies with [1, 2-dimethyl-14C]choline-O-sulfate showed that its transport was stimulated by high osmolality, and kinetic analysis revealed that OpuC has high affinity for choline-O-sulfate, with a Km value of 4 +/- 1 microM and a maximum rate of transport (Vmax) of 54 +/- 3 nmol/min. mg of protein in cells grown in minimal medium with 0.4 M NaCl. Growth studies utilizing a B. subtilis mutant defective in the choline to glycine betaine synthesis pathway and natural abundance 13C nuclear magnetic resonance spectroscopy of whole-cell extracts from the wild-type strain demonstrated that choline-O-sulfate was accumulated in the cytoplasm and was not hydrolyzed to choline by B. subtilis. In contrast, the osmoprotective effect of acetylcholine for B. subtilis is dependent on its biotransformation into glycine betaine. Choline-O-sulfate was not used as the sole carbon, nitrogen, or sulfur source, and our findings thus characterize this choline ester as an effective compatible solute and metabolically inert stress compound for B. subtilis. OpuC mediates the efficient transport not only of glycine betaine and choline-O-sulfate but also of carnitine, crotonobetaine, and gamma-butyrobetaine (R. Kappes and E. Bremer, Microbiology 144:83-90, 1998). Thus, our data underscore its crucial role in the acquisition of a variety of osmoprotectants from the environment by B. subtilis.
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Affiliation(s)
- G Nau-Wagner
- Philipps University Marburg, Department of Biology, D-35032 Marburg, Federal Republic of Germany
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23
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Abstract
All microorganisms possess a positive turgor, and maintenance of this outward-directed pressure is essential since it is generally considered as the driving force for cell expansion. Exposure of microorganisms to high-osmolality environments triggers rapid fluxes of cell water along the osmotic gradient out of the cell, thus causing a reduction in turgor and dehydration of the cytoplasm. To counteract the outflow of water, microorganisms increase their intracellular solute pool by amassing large amounts of organic osmolytes, the so-called compatible solutes. These osmoprotectants are highly congruous with the physiology of the cell and comprise a limited number of substances including the disaccharide trehalose, the amino acid proline, and the trimethylammonium compound glycine betaine. The intracellular amassing of compatible solutes as an adaptive strategy to high-osmolality environments is evolutionarily well-conserved in Bacteria, Archaea, and Eukarya. Furthermore, the nature of the osmolytes that are accumulated during water stress is maintained across the kingdoms, reflecting fundamental constraints on the kind of solutes that are compatible with macromolecular and cellular functions. Generally, compatible solutes can be amassed by microorganisms through uptake and synthesis. Here we summarise the molecular mechanisms of compatible solute accumulation in Escherichia coli and Bacillus subtilis, model organisms for the gram-negative and gram-positive branches of bacteria.
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Affiliation(s)
- B Kempf
- Philipps Universität Marburg, Laboratorium für Mikrobiologie, Germany
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24
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Spiegelhalter F, Bremer E. Osmoregulation of the opuE proline transport gene from Bacillus subtilis: contributions of the sigma A- and sigma B-dependent stress-responsive promoters. Mol Microbiol 1998; 29:285-96. [PMID: 9701821 DOI: 10.1046/j.1365-2958.1998.00929.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The opuE gene from Bacillus subtilis encodes a transport system (OpuE) for osmoprotective proline uptake and is expressed from two osmoregulated promoters: opuE P-1 recognized by the vegetative sigma factor A (sigma A and opuE P-2 dependent on the stress-induced transcription factor sigma B (sigma B). The contributions of these two promoters to osmoregulation of opuE were analysed. Genetic studies using chromosomal opuE-treA operon fusions revealed that opuE transcription is rapidly induced after an osmotic upshock. The strength of opuE expression is proportionally linked to the osmolarity of the growth medium. Deletion analysis of the opuE regulatory region identified a 330 bp DNA segment carrying all sequences required in cis for full and osmoregulated transcription. The proper rotational orientation of the upstream region present within this fragment was essential for the function of both opuE promoters. Mutant opuE-treA fusions with defects in either the sigma A-or the sigma B-dependent promoters revealed different contributions of these sequences to the overall osmoregulation of opuE. opuE P-2 (sigma B) activity increased transiently after an osmotic upshock and did not significantly contribute to the level of opuE expression in cells subjected to long-term osmotic stress. In contrast, transcription initiating from opuE P-1 (sigma A) rose in proportion to the external osmolarity and was maintained at high levels. Moreover, both promoters exhibited a different response to the osmoprotectant glycine betaine in the medium. Our results suggest that at least two different signal transduction pathways operate in B. subtilis to communicate osmotic changes in the environment to the transcription apparatus of the cell.
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25
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Abstract
Osmotic movement of water across bacterial cell membranes is postulated to be a homeostatic mechanism for maintaining cell turgor. The molecular water transporter remained elusive until discovery of the Escherichia coli water channel, AqpZ, however the regulation of the aqpZ gene expression and physiological function of the AqpZ protein are unknown. Northern analysis revealed a transcript of 0.7 kb, confirming the monocistronic nature of aqpZ. Regulatory studies performed with an aqpZ::lacZ low copy plasmid demonstrate enhanced expression during mid-logarithmic growth, and expression of the gene is dependent upon the extracellular osmolality, which increased in hypoosmotic environments but strongly reduced in hyperosmolar NaCl or KCl. While disruption of the chromosomal aqpZ is not lethal for E. coli, the colonies of the aqpZ knockout mutant are smaller than those of the parental wild-type strain. When cocultured with parental wild-type E. coli, the aqpZ knockout mutant exhibits markedly reduced colony formation when grown at 39 degrees C. Similarly, the aqpZ knockout mutant also exhibits greatly reduced colony formation when grown at low osmolality, but this phenotype is reversed by overexpression of AqpZ protein. These results implicate AqpZ as a participant in the adaptive response of E. coli to hypoosmotic environments and indicate a requirement for AqpZ by rapidly growing cells.
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Affiliation(s)
- G Calamita
- Dipartimento di Fisiologia Generale ed Ambientale, University of Bari, via Amendola, 165/A, 70126 Bari, Italy.
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26
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Boch J, Nau-Wagner G, Kneip S, Bremer E. Glycine betaine aldehyde dehydrogenase from Bacillus subtilis: characterization of an enzyme required for the synthesis of the osmoprotectant glycine betaine. Arch Microbiol 1997; 168:282-9. [PMID: 9297465 DOI: 10.1007/s002030050500] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Production of the compatible solute glycine betaine from its precursors choline or glycine betaine aldehyde confers a considerable level of tolerance against high osmolarity stress to the soil bacterium Bacillus subtilis. The glycine betaine aldehyde dehydrogenase GbsA is an integral part of the osmoregulatory glycine betaine synthesis pathway. We strongly overproduced this enzyme in an Escherichia coli strain that expressed a plasmid-encoded gbsA gene under T7φ10 control. The recombinant GbsA protein was purified 23-fold to apparent homogeneity by fractionated ammonium sulfate precipitation, ion-exchange chromatography on Q-Sepharose, and subsequent hydrophobic interaction chromatography on phenyl-Sepharose. Molecular sieving through Superose 12 and sedimentation centrifugation through a glycerol gradient suggested that the native enzyme is a homodimer with 53.7-kDa subunits. The enzyme was specific for glycine betaine aldehyde and could use both NAD+ and NADP+ as cofactors, but NAD+ was strongly preferred. A kinetic analysis of the GbsA-mediated oxidation of glycine betaine aldehyde to glycine betaine revealed Km values of 125 microM and 143 microM for its substrates glycine betaine aldehyde and NAD+, respectively. Low concentrations of salts stimulated the GbsA activity, and the enzyme was highly tolerant of high ionic conditions. Even in the presence of 2.4 M KCl, 88% of the initial enzymatic activity was maintained. B. subtilis synthesizes high levels of proline when grown at high osmolarity, and the presence of this amino acid strongly stimulated the GbsA activity in vitro. The enzyme was stimulated by moderate concentrations of glycine betaine, and its activity was highly tolerant against molar concentrations of this osmolyte. The high salt tolerance and its resistance to its own reaction product are essential features of the GbsA enzyme and ensure that B. subtilis can produce high levels of the compatible solute glycine betaine under conditions of high osmolarity stress.
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Affiliation(s)
- J Boch
- Philipps Universität, Department of Biology, Laboratory for Microbiology, Karl-von-Frisch-Strasse, D-35032 Marburg, Germany
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27
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Kempf B, Gade J, Bremer E. Lipoprotein from the osmoregulated ABC transport system OpuA of Bacillus subtilis: purification of the glycine betaine binding protein and characterization of a functional lipidless mutant. J Bacteriol 1997; 179:6213-20. [PMID: 9335265 PMCID: PMC179532 DOI: 10.1128/jb.179.20.6213-6220.1997] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The OpuA transport system of Bacillus subtilis functions as a high-affinity uptake system for the osmoprotectant glycine betaine. It is a member of the ABC transporter superfamily and consists of an ATPase (OpuAA), an integral membrane protein (OpuAB), and a hydrophilic polypeptide (OpuAC) that shows the signature sequence of lipoproteins (B. Kempf and E. Bremer, J. Biol. Chem. 270:16701-16713, 1995). The OpuAC protein might thus serve as an extracellular substrate binding protein anchored in the cytoplasmic membrane via a lipid modification at an amino-terminal cysteine residue. A malE-opuAC hybrid gene was constructed and used to purify a lipidless OpuAC protein. The purified protein bound radiolabeled glycine betaine avidly and exhibited a KD of 6 microM for this ligand, demonstrating that OpuAC indeed functions as the substrate binding protein for the B. subtilis OpuA system. We have selectively expressed the opuAC gene under T7 phi10 control in Escherichia coli and have demonstrated through its metabolic labeling with [3H]palmitic acid that OpuAC is a lipoprotein. A mutant expressing an OpuAC protein in which the amino-terminal cysteine residue was changed to an alanine (OpuAC-3) was constructed by oligonucleotide site-directed mutagenesis. The OpuAC-3 protein was not acylated by [3H]palmitic acid, and part of it was secreted into the periplasmic space of E. coli, where it could be released from the cells by cold osmotic shock. The opuAC-3 mutation was recombined into an otherwise wild-type opuA operon in the chromosome of B. subtilis. Unexpectedly, this mutant OpuAC system still functioned efficiently for glycine betaine acquisition in vivo under high-osmolarity growth conditions. In addition, the mutant OpuA transporter exhibited kinetic parameters similar to that of the wild-type system. Our data suggest that the lipidless OpuAC-3 protein is held in the cytoplasmic membrane of B. subtilis via its uncleaved hydrophobic signal peptide.
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Affiliation(s)
- B Kempf
- Department of Biology, Philipps University Marburg, Germany
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28
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Calamita G, Kempf B, Rudd KE, Bonhivers M, Kneip S, Bishai WR, Bremer E, Agre P. The aquaporin-Z water channel gene of Escherichia coli: structure, organization and phylogeny. Biol Cell 1997; 89:321-9. [PMID: 9468603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aquaporin water channel proteins are found throughout the plant and animal kingdoms, but the first prokaryotic water channel gene, aqpZ, was only recently identified in wild type Escherichia coli (Calamita G et al (1995) J Biol Chem 270, 29063-29066). Here we define the organization of aqpZ in E coli, produce the AqpZ protein and compare the AqpZ phylogeny to that of some known bacterial homologs. Physical mapping and sequence analyses confirmed the location of aqpZ at minute 19.7 on the E coli chromosome where it is transcribed counterclockwise. The monocistronic nature of aqpZ was clearly indicated by the structural organization of its surrounding genes, ybjD and ybjE' and by the presence of a typical Rho-independent transcriptional terminator following the aqpZ stop codon. Computer sequence analysis indicated the -35/-10 region located 72 bases upstream of the aqpZ start codon as the most likely aqpZ promoter. A series of potential cis-regulatory elements were found in the 400 bp region preceding the aqpZ ORF. The AqpZ protein, produced under T7 phi 10 control, showed a size of about 20 kDa by SDS-PAGE. Striking similarities were found between the E coli aqpZ and a gene included in the genome of the cyanobacterium Synechocystis sp PCC6803, a species permanently living a fresh water. These results may represent a fundamental step to characterize the regulation and the physiological features of the AqpZ water channel in prokaryotes.
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Affiliation(s)
- G Calamita
- Istituto di Fisiologia Generale, Università degli Studi di Bari, Italy
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29
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von Blohn C, Kempf B, Kappes RM, Bremer E. Osmostress response in Bacillus subtilis: characterization of a proline uptake system (OpuE) regulated by high osmolarity and the alternative transcription factor sigma B. Mol Microbiol 1997; 25:175-87. [PMID: 11902719 DOI: 10.1046/j.1365-2958.1997.4441809.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Exogenously provided proline has been shown to serve as an osmoprotectant in Bacillus subtilis. Uptake of proline is under osmotic control and functions independently of the known transport systems for the osmoprotectant glycine betaine. We cloned the structural gene (opuE) for this proline transport system and constructed a chromosomal opuE mutant by marker replacement. The resulting B. subtilis strain was entirely deficient in osmoregulated proline transport activity and was no longer protected by exogenously provided proline, attesting to the central importance of OpuE for proline uptake in high-osmolarity environments. The transport characteristics and growth properties of the opuE mutant revealed the presence of a second proline transport activity in B. subtilis. DNA sequence analysis of the opuE region showed that the OpuE transporter (492 residues) consists of a single integral membrane protein. Database searches indicated that OpuE is a member of the sodium/solute symporter family, comprising proteins from both prokaryotes and eukaryotes that obligatorily couple substrate uptake to Na+ symport. The highest similarity was detected to the PutP proline permeases, which are used in Escherichia coli, Salmonella typhimurium and Staphylococcus aureus for the acquisition of proline as a carbon and nitrogen source, but not for osmoprotective purposes. An elevation of the osmolarity of the growth medium by either ionic or non-ionic osmolytes resulted in a strong increase in the OpuE-mediated proline uptake. This osmoregulated proline transport activity was entirely dependent on de novo protein synthesis, suggesting a transcriptional control mechanism. Primer extension analysis revealed the presence of two osmoregulated and tightly spaced opuE promoters. The activity of one of these promoters was dependent on sigma A and the second promoter was controlled by the general stress transcription factor sigma B.
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Affiliation(s)
- C von Blohn
- Philipps University Marburg, Department of Biology, Germany
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30
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Janzen H, Campbell C, Ellert B, Bremer E. Chapter 12 Soil organic matter dynamics and their relationship to soil quality. Soil Quality for Crop Production and Ecosystem Health 1997. [DOI: 10.1016/s0166-2481(97)80039-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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31
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Haardt M, Bremer E. Use of phoA and lacZ fusions to study the membrane topology of ProW, a component of the osmoregulated ProU transport system of Escherichia coli. J Bacteriol 1996; 178:5370-81. [PMID: 8808924 PMCID: PMC178353 DOI: 10.1128/jb.178.18.5370-5381.1996] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Escherichia coli ProU system is a member of the ATP-binding cassette (ABC) superfamily of transporters. ProU consists of three components (ProV, ProW, and ProX) and functions as a high-affinity, binding protein-dependent transport system for the osmoprotectants glycine betaine and proline betaine. The ProW protein is the integral inner membrane component of the ProU system. Its hydropathy profile predicts seven transmembrane spans and a hydrophilic amino terminus of approximately 100 residues, and it suggests the presence of an amphiphilic alpha-helix (L-61 to F-97) in close proximity to the first strongly hydrophobic segment of ProW. We have studied the membrane topology of the ProW protein by the phoA and lacZ gene fusion approach. A collection of 10 different proW-phoA fusions with alkaline phosphatase activity and 8 different proW-lacZ fusions with beta-galactosidase activity were isolated in vivo after TnphoAB and TnlacZ mutagenesis of a plasmid-encoded proW gene. The recovery of both enzymatically active ProW-PhoA and ProW-LacZ hybrid proteins indicates that segments of ProW are exposed on both sides of the cytoplasmic membrane. To compare the enzymatic activities of each of the indicator proteins joined at a particular site in ProW, we switched the phoA and lacZ reporter genes in vitro in each of the originally in vivo-isolated gene fusions. A mirror-like pattern in the enzyme activity of the resulting new ProW-PhoA and ProW-LacZ hybrid proteins emerged, thus providing positive signals for the location of both periplasmic and cytoplasmic domains in ProW. The protease kallikrein digests the amino-terminal tail of a ProW-LacZ hybrid protein in spheroplasts, suggesting that the amino terminus of ProW is located on the periplasmic side of the cytoplasmic membrane. From these data, a two-dimensional model for ProW was constructed; this model consists of seven transmembrane alpha-helices and an unusual amino-terminal tail of approximately 100 amino acid residues that protrudes into the periplasmic space.
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Affiliation(s)
- M Haardt
- Department of Biology, University of Konstanz, Germany
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32
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Abstract
The accumulation of the osmoprotectant glycine betaine from exogenous sources provides a high degree of osmotic tolerance to Bacillus subtilis. We have identified, through functional complementation of an Escherichia coli mutant defective in glycine betaine uptake, a new glycine betaine transport system from B. subtilis. The DNA sequence of a 2,310-bp segment of the cloned region revealed a single gene (opuD) whose product (OpuD) was essential for glycine betaine uptake and osmoprotection in E. coli. The opuD gene encodes a hydrophobic 56.13-kDa protein (512 amino acid residues). OpuD shows a significant degree of sequence identity to the choline transporter BetT and the carnitine transporter CaiT from E. coli and a BetT-like protein from Haemophilus influenzae. These membrane proteins form a family of transporters involved in the uptake of trimethylammonium compounds. The OpuD-mediated glycine betaine transport activity in B. subtilis is controlled by the environmental osmolarity. High osmolarity stimulates de novo synthesis of OpuD and activates preexisting OpuD proteins to achieve maximal glycine betaine uptake activity. An opuD mutant was constructed by marker replacement, and the OpuD-mediated glycine betaine uptake activity was compared with that of the previously identified multicomponent OpuA and OpuC (ProU) glycine betaine uptake systems. In addition, a set of mutants was constructed, each of which synthesized only one of the three glycine betaine uptake systems. These mutants were used to determine the kinetic parameters for glycine betaine transport through OpuA, OpuC, and OpuD. Each of these uptake systems shows high substrate affinity, with Km values in the low micromolar range, which should allow B. subtilis to efficiently acquire the osmoprotectant from the environment. The systems differed in their contribution to the overall glycine betaine accumulation and osmoprotection. A triple opuA, opuC, and opuD mutant strain was isolated, and it showed no glycine betaine uptake activity, demonstrating that three transport systems for this osmoprotectant operate in B. subtilis.
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Affiliation(s)
- R M Kappes
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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33
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Abstract
Synthesis of the osmoprotectant glycine betaine from the exogenously provided precursor choline or glycine betaine aldehyde confers considerable osmotic stress tolerance to Bacillus subtilis in high-osmolarity media. Using an Escherichia coli mutant (betBA) defective in the glycine betaine synthesis enzymes, we cloned by functional complementation the genes that are required for the synthesis of the osmoprotectant glycine betaine in B. subtilis. The DNA sequence of a 4.1-kb segment from the cloned chromosomal B. subtilis DNA was established, and two genes (gbsA and gbsB) whose products were essential for glycine betaine biosynthesis and osmoprotection were identified. The gbsA and gbsB genes are transcribed in the same direction, are separated by a short intergenic region, and are likely to form an operon. The deduced gbsA gene product exhibits strong sequence identity with members of a superfamily of specialized and nonspecialized aldehyde dehydrogenases. This superfamily comprises glycine betaine aldehyde dehydrogenases from bacteria and plants with known involvement in the cellular adaptation to high-osmolarity stress and drought. The deduced gbsB gene product shows significant similarity to the family of type III alcohol dehydrogenases. B. subtilis mutants with defects in the chromosomal gbsAB genes were constructed by marker replacement, and the growth properties of these mutant strains in high-osmolarity medium were analyzed. Deletion of the gbsAB genes destroyed the choline-glycine betaine synthesis pathway and abolished the ability of B. subtilis to deal effectively with high-osmolarity stress in choline- or glycine betaine aldehyde-containing medium. Uptake of radiolabelled choline was unaltered in the gbsAB mutant strain. The continued intracellular accumulation of choline or glycine betaine aldehyde in a strain lacking the glycine betaine-biosynthetic enzymes strongly interfered with the growth of B. subtilis, even in medium of moderate osmolarity. A single transcription initiation site for gbsAB was detected by high-resolution primer extension analysis. gbsAB transcription was initiated from a promoter with close homology to sigma A-dependent promoters and was stimulated by the presence of choline in the growth medium.
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Affiliation(s)
- J Boch
- Max-Planck Institute for Terrestrial Microbiology, Federal Republic of Germany
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Abstract
The nucleotide sequence of a new Bacillus subtilis gene (amhX) was determined that encodes a protein (AmhX) with strong sequence identity to amidohydrolases from both plant and bacterial species and a carboxypeptidase from the archaeon Sulfolobus sulfataricus. The amhX gene encodes a hydrophilic polypeptide of 383 amino acids with a molecular mass of 41.5 kDa. The amhX gene was overexpressed in E. coli by using the T7 RNA polymerase/promoter system and the transcription initiation sites for the amhX mRNAs in B. subtilis were determined by primer extension analysis. Chromosomal amhX mutations were constructed by marker replacement and the amhX gene was positioned at 25 degrees on the genetic and physical map of the B. subtilis chromosome.
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Affiliation(s)
- B Kempf
- Max-Planck-Institut für Terrestrische Mikrobiologie, Karl-von-Frisch Strasse, Marburg, Germany
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35
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Behrends HB, Bremer E. [The problem of refuse in hospitals]. Krankenpfl J 1995; 33:428-32. [PMID: 8538136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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36
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Kempf B, Bremer E. OpuA, an osmotically regulated binding protein-dependent transport system for the osmoprotectant glycine betaine in Bacillus subtilis. J Biol Chem 1995; 270:16701-13. [PMID: 7622480 DOI: 10.1074/jbc.270.28.16701] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Exogenously provided glycine betaine can efficiently protect Bacillus subtilis from the detrimental effects of high osmolarity environments. Through functional complementation of an Escherichia coli mutant deficient in glycine betaine uptake with a gene library from B. subtilis, we have identified a multicomponent glycine betaine transport system, OpuA. Uptake of radiolabeled glycine betaine in B. subtilis was found to be osmotically stimulated and was strongly decreased in a mutant strain lacking the OpuA transport system. DNA sequence analysis revealed that the components of the OpuA system are encoded by anoperon (opuA) comprising three structural genes: opuAA, opuAB, and opuAC. The products of these genes exhibit features characteristic for binding protein-dependent transport systems and in particular show homology to the glycine betaine uptake system ProU from E. coli. Expression of the opuA operon is under osmotic control. The transcriptional initiation sites of opuA were mapped by high resolution primer extension analysis, and two opuA mRNAs were detected that differed by 38 base pairs at their 5' ends. Synthesis of the shorter transcript was strongly increased in cells grown at high osmolarity, whereas the amount of the longer transcript did not vary in response to medium osmolarity. Physical and genetic mapping experiments allowed the positioning the opuA operon at 25 degrees on the genetic map of B. subtilis.
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Affiliation(s)
- B Kempf
- Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
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37
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Haardt M, Kempf B, Faatz E, Bremer E. The osmoprotectant proline betaine is a major substrate for the binding-protein-dependent transport system ProU of Escherichia coli K-12. Mol Gen Genet 1995; 246:783-6. [PMID: 7898450 DOI: 10.1007/bf00290728] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The ProP and ProU transport systems of Escherichia coli mediate the uptake of several osmoprotectants including glycine betaine. Here we report that both ProP and ProU are involved in the transport of the potent osmoprotectant proline betaine. A set of isogenic E. coli strains carrying deletions in either the proP or proU loci was constructed. The growth properties of these mutants in high osmolarity minimal media containing 1 mM proline betaine demonstrated that the osmoprotective effect of this compound was dependent on either an intact ProP or ProU uptake system. Proline betaine competes with glycine betaine for binding to the proU-encoded periplasmic substrate binding protein (ProX) and we estimate a KD of 5.2 microM for proline betaine binding. This value is similar to the binding constant of the ProX protein determined previously for the binding of glycine betaine (KD of 1.4 microM). Our results thus demonstrate that the binding-protein-dependent ProU transport system of E. coli mediates the efficient uptake of the osmoprotectants glycine betaine and proline betaine.
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Affiliation(s)
- M Haardt
- University of Konstanz, Department of Biology, Federal Republic of Germany
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38
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Abstract
Expression of the proU operon of Escherichia coli is directly proportional to the osmolarity of the growth medium. The basal level of proU transcription is very low, but a large increase is triggered by a sudden rise in the external osmolarity. This increased expression is maintained for as long as the osmotic stimulus persists. We have capitalized upon these regulatory features of the proU operon and have constructed a series of expression vectors (pOSEX) permitting osmotically controlled expression of heterologous genes governed by regulatory signals of proU. The pOSEX vectors carry the proU promoter, an upstream region required for high-level expression, and part of the first structural gene (proV), which acts as a silencer and is necessary to maintain low-level expression in low osmolarity media. An extended multiple cloning site (MCS) positioned at the 3' end of proV' permits the cloning of heterologous genes into the pOSEX plasmids, and efficient transcription terminators derived from the rrnB operon prevent deleterious read-through transcription into the vector portion. The properties of the pOSEX expression vectors were tested by positioning a promoterless lacZ (encoding beta-galactosidase) gene from E. coli and the gcdA (encoding carboxytransferase) gene from the Gram+ bacterium Acidaminococcus fermentans under the control of the proU regulatory region. Efficient, osmo-regulated and finely tuned expression of both lacZ and gcdA was achieved, and the amount of beta-galactosidase and carboxytransferase synthesized were simply controlled by adjusting the osmolarity of the growth medium with various concentrations of NaCl.
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Affiliation(s)
- B Herbst
- Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany
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39
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Dersch P, Kneip S, Bremer E. The nucleoid-associated DNA-binding protein H-NS is required for the efficient adaptation of Escherichia coli K-12 to a cold environment. Mol Gen Genet 1994; 245:255-9. [PMID: 7816034 DOI: 10.1007/bf00283274] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The hns gene is a member of the cold-shock regulon, indicating that the nucleoid-associated, DNA-binding protein H-NS plays an important role in the adaptation of Escherichia coli to low temperatures. We show here that the ability to cope efficiently with a cold environment (12 degrees C and 25 degrees C) is strongly impaired in E. coli strains carrying hns mutations. Growth inhibition is much more pronounced in strains carrying the hns-206 allele (an ampicillin resistance cassette inserted after codon 37) than in those carrying the hns-205 mutation (a Tn10 insertion located in codon 93). A protein fragment (H-NS*) is synthesized in strains carrying the hns-205::Tn10 mutation, suggesting that this truncated polypeptide is partially functional in the cold adaptation process. Analysis of the growth properties of strains harbouring four different low-copy-number plasmid-encoded hns' genes that result in the production of C-terminally truncated H-NS proteins supports this proposal. H-NS* proteins composed of 133, 117 or 94 amino-terminal amino acids partially complemented the severe cold-sensitive growth phenotype of the hns-206 mutant. In contrast, synthesis of a truncated H-NS protein with only 75 amino-terminal amino acids was insufficient to restore growth at low temperature.
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Affiliation(s)
- P Dersch
- Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany
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40
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Abstract
A set of low-copy-number vectors (pPD) has been constructed that permit selective gene expression and high-level protein overproduction in Escherichia coli, based on the bacteriophage T7 RNA polymerase/T7 promoter system. These plasmids carry a chloramphenicol resistance gene (cat) as a selective marker and an extended multiple cloning site for convenient gene cloning. Their replication is mediated by ori sequences derived from the low-copy-number vector pSC101. The efficient T7 gene 10 promoter present on these vectors allows selective and high-level transcription of cloned genes carrying their own translational initiation signals. In addition, low-copy-number T7 vectors were constructed that permit expression of genes lacking their own transcription and translation initiation elements by providing a ribosome binding site, an ATG start codon and a multiple cloning site devised for the cloning in all three reading frames. The pPD expression vectors were used to achieve high-level overproduction of the E. coli integral outer membrane protein Tsx, and the cytoplasmic enzymes beta-galactosidase (beta Gal) and UTP:alpha-D-glucose-1-phosphate uridylyltransferase (GalU). The characteristics of these low-copy-number T7 expression vectors should prove very useful for the cloning and high-level overexpression of genes whose gene products are deleterious to the E. coli host.
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Affiliation(s)
- P Dersch
- Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, FRG
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41
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Whitley P, Zander T, Ehrmann M, Haardt M, Bremer E, von Heijne G. Sec-independent translocation of a 100-residue periplasmic N-terminal tail in the E. coli inner membrane protein proW. EMBO J 1994; 13:4653-61. [PMID: 7925306 PMCID: PMC395399 DOI: 10.1002/j.1460-2075.1994.tb06788.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The ProW protein, located in the inner membrane of Escherichia coli, has a very unusual topology with a 100-residue-long N-terminal tail protruding into the periplasmic space. We have studied the mechanism of membrane translocation of the periplasmic tail by analysing ProW-PhoA and ProW-Lep fusion proteins, both in wild-type cells and in cells with an impaired sec machinery. Our results show that the translocation efficiency is not affected by treatments that compromise the SecA and SecY functions, but that translocation is completely blocked by dissipation of the proton motive force or by the introduction of extra positively charged residues into the N-terminal tail. This suggests that the sec machinery can act properly only on domains located on the C-terminal side of a translocation signal, and that the N-terminal tail is driven through the membrane by a mechanism that involves the proton motive force.
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Affiliation(s)
- P Whitley
- Department of Molecular Biology, Karolinska Institute Center for Structural Biochemistry, NOVUM, Huddinge, Sweden
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42
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Abstract
Exogenously provided glycine betaine functions as an efficient osmoprotectant for Bacillus subtilis in high-osmolarity environments. This gram-positive soil organism is not able to increase the intracellular level of glycine betaine through de novo synthesis in defined medium (A. M. Whatmore, J. A. Chudek, and R. H. Reed, J. Gen. Microbiol. 136:2527-2535, 1990). We found, however, that B. subtilis can synthesize glycine betaine when its biosynthetic precursor, choline, is present in the growth medium. Uptake studies with radiolabelled [methyl-14C]choline demonstrated that choline transport is osmotically controlled and is mediated by a high-affinity uptake system. Choline transport of cells grown in low- and high-osmolarity media showed Michaelis-Menten kinetics with Km values of 3 and 5 microM and maximum rates of transport (Vmax) of 10 and 36 nmol min-1 mg of protein-1, respectively. The choline transporter exhibited considerable substrate specificity, and the results of competition experiments suggest that the fully methylated quaternary ammonium group is a key feature for substrate recognition. Thin-layer chromatography revealed that the radioactivity from exogenously provided [methyl-14C]choline accumulated intracellularly as [methyl-14C]glycine betaine, demonstrating that B. subtilis possesses enzymes for the oxidative conversion of choline into glycine betaine. Exogenously provided choline significantly increased the growth rate of B. subtilis in high-osmolarity media and permitted its proliferation under conditions that are otherwise strongly inhibitory for its growth. Choline and glycine betaine were not used as sole sources of carbon or nitrogen, consistent with their functional role in the process of adaptation of B. subtilis to high-osmolarity stress.
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Affiliation(s)
- J Boch
- Max-Planck Institute for Terrestrial Microbiology, Marburg, Federal Republic of Germany
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43
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Lucht JM, Bremer E. Adaptation of Escherichia coli to high osmolarity environments: osmoregulation of the high-affinity glycine betaine transport system proU. FEMS Microbiol Rev 1994; 14:3-20. [PMID: 8011357 DOI: 10.1111/j.1574-6976.1994.tb00067.x] [Citation(s) in RCA: 205] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A sudden increase in the osmolarity of the environment is highly detrimental to the growth and survival of Escherichia coli and Salmonella typhimurium since it triggers a rapid efflux of water from the cell, resulting in a decreased turgor. Changes in the external osmolarity must therefore be sensed by the microorganisms and this information must be converted into an adaptation process that aims at the restoration of turgor. The physiological reaction of the cell to the changing environmental condition is a highly coordinated process. Loss of turgor triggers a rapid influx of K+ ions into the cell via specific transporters and the concomitant synthesis of counterions, such as glutamate. The increased intracellular concentration of K(+)-glutamate allows the adaptation of the cell to environments of moderately high osmolarities. At high osmolarity, K(+)-glutamate is insufficient to ensure cell growth, and the bacteria therefore replace the accumulated K+ ions with compounds that are less deleterious for the cell's physiology. These compatible solutes include polyoles such as trehalose, amino acids such as proline, and methyl-amines such as glycine betaine. One of the most important compatible solutes for bacteria is glycine betaine. This potent osmoprotectant is widespread in nature, and its intracellular accumulation is achieved through uptake from the environment or synthesis from its precursor choline. In this overview, we discuss the properties of the high-affinity glycine betaine transport system ProU and the osmotic regulation of its structural genes.
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Affiliation(s)
- J M Lucht
- University of Konstanz, Department of Biology, FRG
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44
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Lucht JM, Dersch P, Kempf B, Bremer E. Interactions of the nucleoid-associated DNA-binding protein H-NS with the regulatory region of the osmotically controlled proU operon of Escherichia coli. J Biol Chem 1994; 269:6578-8. [PMID: 8120010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Escherichia coli hns gene encodes the abundant nucleoid-associated DNA-binding protein H-NS. Mutations in hns alter the expression of many genes with unrelated functions and result in a derepression of the proU operon (proVWX) without abolishing the osmotic control of its transcription. We have investigated the interactions of H-NS with the proU regulatory region by deletion analysis of cis-acting sequences, competitive gel retardation assays, and DNase I footprinting. The negative effect of H-NS on proU transcription was mediated by cis-acting sequences within proV but did not depend on the presence of a curved DNA segment upstream of the proU-35 region previously characterized as a target for H-NS binding in vitro. We detected a 46-base pair high affinity H-NS binding region downstream of the proU promoter at the 5' end of the proV gene and a complex array of additional H-NS binding sites which suggest the presence of an extended H-NS nucleoprotein complex. Most of the H-NS binding sites were highly A+T-rich and carried stretches of 5 or more consecutive A-T base pairs. The implications of our results for the osmotic regulation of proU transcription are discussed.
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Affiliation(s)
- J M Lucht
- Department of Biology, University of Konstanz, Germany
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45
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Lucht J, Dersch P, Kempf B, Bremer E. Interactions of the nucleoid-associated DNA-binding protein H-NS with the regulatory region of the osmotically controlled proU operon of Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37411-2] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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46
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Fsihi H, Kottwitz B, Bremer E. Single amino acid substitutions affecting the substrate specificity of the Escherichia coli K-12 nucleoside-specific Tsx channel. J Biol Chem 1993; 268:17495-503. [PMID: 8349629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The Tsx protein from the Escherichia coli outer membrane is a channel-forming protein containing a nucleoside-specific binding site. The antibiotic albicidin enters the cell via this substrate-specific channel. Because albicidin is toxic for E. coli at a very low external substrate concentration, the Tsx channel is likely to contain a binding site for this antibiotic. To identify residues involved in the Tsx substrate-specific channel activity, we devised a selection scheme to isolate albicidin-resistant tsx mutants synthesizing Tsx proteins with defects in their nucleoside uptake function. We recovered seven distinct albicidin-resistant tsx alleles, six point mutations and a 39-base pair duplication. The mutants with a duplication of residues 21-33 of Tsx or with single amino acid substitutions of residue Gly28 (to Arg) and Ser217 (to Arg) are completely deficient in nucleoside uptake at a low substrate concentration. Substitutions of Phe27 to Leu, Gly28 to Glu, Gly239 to Asp, and Gly240 to Asp result in a Tsx protein partially defective in nucleoside transport. These mutant proteins still permit nonspecific diffusion of serine indicating that the mutations do not result in a block of the Tsx channel. Our results are discussed in terms of a model for the topological organization of the Tsx protein within the outer membrane of E. coli.
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Affiliation(s)
- H Fsihi
- Department of Biology, University of Konstanz, Germany
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47
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Fsihi H, Kottwitz B, Bremer E. Single amino acid substitutions affecting the substrate specificity of the Escherichia coli K-12 nucleoside-specific Tsx channel. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)85361-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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48
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Dersch P, Schmidt K, Bremer E. Synthesis of the Escherichia coli K-12 nucleoid-associated DNA-binding protein H-NS is subjected to growth-phase control and autoregulation. Mol Microbiol 1993; 8:875-89. [PMID: 8355613 DOI: 10.1111/j.1365-2958.1993.tb01634.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mutations in the structural gene (hns) for the Escherichia coli nucleoid-associated DNA-binding protein H-NS cause highly pleiotropic effects on gene expression, site-specific recombination, transposition of phage Mu, the stability of the genetic material and the topological state of the DNA. We have investigated the regulation of hns expression and found that hns transcription is subjected to stationary phase induction and negative autoregulation. A set of hns-lacZ protein and operon fusions was constructed in vitro and integrated in single copy into the attB site of the bacterial genome. Quantification of beta-galactosidase activity along the bacterial growth curve showed that hns expression increases approximately 10-fold in stationary phase compared with exponentially growing cells. Immunological detection of the H-NS protein in growing and stationary phase cells supported the genetic data and showed that H-NS synthesis varies with growth phase. In addition, primer extension experiments demonstrated that the amount of hns mRNA is elevated in stationary phase cultures and that hns transcription is directed by a unique promoter functioning in both log and stationary phase. Disruption of the hns gene by an insertion mutation led to the derepression (approximately fourfold) of the expression of an hns-lacZ operon fusion integrated at the attB site, showing that hns transcription is subjected to negative regulation by its own gene product. Autoregulation of hns expression is particularly pronounced in log phase. Both stationary phase control and autoregulation of hns transcription are associated with a 130 bp fragment that contains the hns promoter. In order to study the interaction of H-NS with its own regulatory region, we developed an efficient overproduction procedure and a simple purification scheme for H-NS. DNA gel retardation assays showed that the H-NS protein can preferentially interact with a restriction fragment carrying the hns promoter. This restriction fragment showed features of curved DNA as judged by two-dimensional polyacrylamide gel electrophoresis performed at 4 degrees C and 60 degrees C.
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Affiliation(s)
- P Dersch
- Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany
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Schneider H, Fsihi H, Kottwitz B, Mygind B, Bremer E. Identification of a segment of the Escherichia coli Tsx protein that functions as a bacteriophage receptor area. J Bacteriol 1993; 175:2809-17. [PMID: 8491700 PMCID: PMC204595 DOI: 10.1128/jb.175.10.2809-2817.1993] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Escherichia coli outer membrane protein Tsx functions as a nucleoside-specific channel and serves as the receptor for colicin K and a number of T-even-type bacteriophages, including phage T6. To identify those segments of the Tsx protein that are important for its phage receptor function, we devised a selection and screening procedure which allowed us to isolate phage-resistant strains synthesizing normal amounts of Tsx. Three different Tsx-specific phages (T6, Ox1, and H3) were employed for the selection of phage-resistant derivatives of a strain expressing a tsx(+)-lacZ+ operon fusion, and 28 tsx mutants with impaired phage receptor function were characterized. Regardless of the Tsx-specific phage used for the initial mutant selection, cross-resistance against a set of six different Tsx phages invariably occurred. With one exception, these mutant Tsx proteins could still serve as a colicin K receptor. DNA sequence analysis of 10 mutant tsx genes revealed the presence of four distinct tsx alleles: two point mutations, an 18-bp deletion, and a 27-bp tandem duplication. In three isolates, Asn-249 was replaced by a Lys residue (tsx-504), and in four others, residue Asn-254 was replaced by Lys (tsx-505). The deletion (tsx-506; one isolate) removed six amino acids (residue 239 to residue 244) from the 272-residue Tsx polypeptide chain, and the DNA duplication (tsx-507; two isolates) resulted in the addition of nine extra amino acids (residue 229 to residue 237) to the Tsx protein. In contrast to the wild-type Tsx protein and the other mutant Tsx proteins the Tsx-507 protein was cleaved by trypsin when intact cells were treated with this protease. The Tsx proteins encoded by the four tsx alleles still functioned in deoxyadenosine uptake in vivo, demonstrating that their nucleoside-specific channel activity was not affected by the alterations that caused the loss of their phage receptor function. HTe changes in the Tsx polypeptide that confer resistance against the Tsx-specific phages are clustered in a small region near the carboxy terminus of Tsx. Our results are discussed in terms of a model for the topological organization of the carboxy-terminal end of the Tsx protein within the outer membrane.
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Affiliation(s)
- H Schneider
- Department of Biology, University of Konstanz, Germany
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Pedersen H, Søgaard-Andersen L, Holst B, Gerlach P, Bremer E, Valentin-Hansen P. cAMP-CRP activator complex and the CytR repressor protein bind co-operatively to the cytRP promoter in Escherichia coli and CytR antagonizes the cAMP-CRP-induced DNA bend. J Mol Biol 1992; 227:396-406. [PMID: 1328649 DOI: 10.1016/0022-2836(92)90896-r] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Initiation of transcription from the cytRP promoter in Escherichia coli is activated by the cAMP-CRP complex and negatively regulated by the CytR repressor protein. By combining gel retardation and footprinting assays, we show that cAMP-CRP binds to a single site centered at position -64 and induces a considerable bend in the DNA. CytR binds to a region immediately downstream from, and partially overlapping, the CRP site, and induces a modest bend into the DNA. In combination, cAMP-CRP and CytR bind co-operatively to cytRP forming a nucleoprotein complex in which the proteins directly interact with each other and bind to the same face of the DNA helix. CytR binding concomitantly antagonizes the cAMP-CRP-induced bend. This study indicates that the minimal DNA region required to obtain CytR regulation consists of a single binding site for each of cAMP-CRP and CytR. The case described here, in which a protein-induced DNA bend is modulated by a second protein, may illustrate a mechanism that applies to other regulatory systems.
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Affiliation(s)
- H Pedersen
- Department of Molecular Biology, Odense University, Denmark
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