1
|
Boerner T, Tin A, Vickers A, Harrington C, Janjigian Y, Ilson D, Wu A, Bott M, Isbell J, Park B, Sihag S, Jones D, Downey R, Shahrokni A, Molena D. SO-6 Novel frailty index predicts short-term outcomes after esophagectomy in elderly patients with esophageal cancer. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.04.405] [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: 11/01/2022] Open
|
2
|
Chan J, Quintanal-Villalonga A, Gao V, Xie Y, Allaj V, Chaudhary O, Masilionis I, Egger J, Chow A, Walle T, Ciampricotti M, Offin M, Lai V, Bott M, Jones D, Hollmann T, Nawy T, Mazutis L, Sen T, Pe'Er D, Rudin C. OA07.01 Signatures of Plasticity and Immunosuppression in a Single-Cell Atlas of Human Small Cell Lung Cancer. J Thorac Oncol 2021. [DOI: 10.1016/j.jtho.2021.08.054] [Citation(s) in RCA: 1] [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: 11/30/2022]
|
3
|
Zelle E, Pfelzer N, Oldiges M, Koch-Koerfges A, Bott M, Nöh K, Wiechert W. An energetic profile of Corynebacterium glutamicum underpinned by measured biomass yield on ATP. Metab Eng 2021; 65:66-78. [PMID: 33722651 DOI: 10.1016/j.ymben.2021.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/17/2021] [Accepted: 03/06/2021] [Indexed: 11/17/2022]
Abstract
The supply and usage of energetic cofactors in metabolism is a central concern for systems metabolic engineering, particularly in case of energy intensive products. One of the most important parameters for systems wide balancing of energetic cofactors is the ATP requirement for biomass formation YATP/Biomass. Despite its fundamental importance, YATP/Biomass values for non-fermentative organisms are still rough estimates deduced from theoretical considerations. For the first time, we present an approach for the experimental determination of YATP/Biomass using comparative 13C metabolic flux analysis (13C MFA) of a wild type strain and an ATP synthase knockout mutant. We show that the energetic profile of a cell can then be deduced from a genome wide stoichiometric model and experimental maintenance data. Particularly, the contributions of substrate level phosphorylation (SLP) and electron transport phosphorylation (ETP) to ATP generation become available which enables the overall energetic efficiency of a cell to be characterized. As a model organism, the industrial platform organism Corynebacterium glutamicum is used. C. glutamicum uses a respiratory type of energy metabolism, implying that ATP can be synthesized either by SLP or by ETP with the membrane-bound F1FO-ATP synthase using the proton motive force (pmf) as driving force. The presence of two terminal oxidases, which differ in their proton translocation efficiency by a factor of three, further complicates energy balancing for this organism. By integration of experimental data and network models, we show that in the wild type SLP and ETP contribute equally to ATP generation. Thus, the role of ETP in respiring bacteria may have been overrated in the past. Remarkably, in the genome wide setting 65% of the pmf is actually not used for ATP synthesis. However, it turns out that, compared to other organisms C. glutamicum still uses its energy budget rather efficiently.
Collapse
Affiliation(s)
- E Zelle
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany
| | - N Pfelzer
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany
| | - M Oldiges
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany
| | - A Koch-Koerfges
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany
| | - M Bott
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany
| | - K Nöh
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany
| | - W Wiechert
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D, 52425, Jülich, Germany.
| |
Collapse
|
4
|
Cormann K, Baumgart M, Bott M. Design von biohybriden Sensoren für organische Säuren mit der Sensordomäne von CitA aus Geobacillus thermoleovorans. CHEM-ING-TECH 2018. [DOI: 10.1002/cite.201855428] [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: 11/12/2022]
Affiliation(s)
- K. U. Cormann
- Forschungszentrum Jülich GmbH; IBG-1: Biotechnologie; Wilhelm-Johnen-Straße 52428 Jülich Deutschland
| | - M. Baumgart
- Forschungszentrum Jülich GmbH; IBG-1: Biotechnologie; Wilhelm-Johnen-Straße 52428 Jülich Deutschland
| | - M. Bott
- Forschungszentrum Jülich GmbH; IBG-1: Biotechnologie; Wilhelm-Johnen-Straße 52428 Jülich Deutschland
| |
Collapse
|
5
|
Williams K, Ayyagari P, Perhounkova Y, Bott M, Herman R, Bossen A. COSTS OF A STAFF COMMUNICATION INTERVENTION TO REDUCE DEMENTIA BEHAVIORS IN NURSING HOME CARE. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.1928] [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: 11/12/2022] Open
Affiliation(s)
| | | | | | - M. Bott
- University of Kansas Medical Center, Kansas City, Kansas
| | - R. Herman
- University of Kansas, Lawrence, Kansas,
| | | |
Collapse
|
6
|
Nguyen GTT, Erlenkamp G, Jäck O, Küberl A, Bott M, Fiorani F, Gohlke H, Groth G. Chalcone-based Selective Inhibitors of a C4 Plant Key Enzyme as Novel Potential Herbicides. Sci Rep 2016; 6:27333. [PMID: 27263468 PMCID: PMC4893628 DOI: 10.1038/srep27333] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [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: 02/03/2016] [Accepted: 05/18/2016] [Indexed: 11/08/2022] Open
Abstract
Weeds are a challenge for global food production due to their rapidly evolving resistance against herbicides. We have identified chalcones as selective inhibitors of phosphoenolpyruvate carboxylase (PEPC), a key enzyme for carbon fixation and biomass increase in the C4 photosynthetic pathway of many of the world's most damaging weeds. In contrast, many of the most important crop plants use C3 photosynthesis. Here, we show that 2',3',4',3,4-Pentahydroxychalcone (IC50 = 600 nM) and 2',3',4'-Trihydroxychalcone (IC50 = 4.2 μM) are potent inhibitors of C4 PEPC but do not affect C3 PEPC at a same concentration range (selectivity factor: 15-45). Binding and modeling studies indicate that the active compounds bind at the same site as malate/aspartate, the natural feedback inhibitors of the C4 pathway. At the whole plant level, both substances showed pronounced growth-inhibitory effects on the C4 weed Amaranthus retroflexus, while there were no measurable effects on oilseed rape, a C3 plant. Growth of selected soil bacteria was not affected by these substances. Our chalcone compounds are the most potent and selective C4 PEPC inhibitors known to date. They offer a novel approach to combat C4 weeds based on a hitherto unexplored mode of allosteric inhibition of a C4 plant key enzyme.
Collapse
Affiliation(s)
- G. T. T. Nguyen
- Biochemical Plant Physiology, Heinrich Heine University Düsseldorf and Bioeconomy Science Center (BioSC), Universitätsstr.1, 40225 Düsseldorf, Germany
| | - G. Erlenkamp
- Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf and Bioeconomy Science Center (BioSC), Universitätsstr.1, 40225 Düsseldorf, Germany
| | - O. Jäck
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich and Bioeconomy Science Center (BioSC), Wilhelm-Johnen-Straße, 52425 Jülich, Germany
| | - A. Küberl
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich and Bioeconomy Science Center (BioSC), Wilhelm-Johnen-Straße, 52425 Jülich, Germany
| | - M. Bott
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich and Bioeconomy Science Center (BioSC), Wilhelm-Johnen-Straße, 52425 Jülich, Germany
| | - F. Fiorani
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich and Bioeconomy Science Center (BioSC), Wilhelm-Johnen-Straße, 52425 Jülich, Germany
| | - H. Gohlke
- Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf and Bioeconomy Science Center (BioSC), Universitätsstr.1, 40225 Düsseldorf, Germany
| | - G. Groth
- Biochemical Plant Physiology, Heinrich Heine University Düsseldorf and Bioeconomy Science Center (BioSC), Universitätsstr.1, 40225 Düsseldorf, Germany
| |
Collapse
|
7
|
Kinast K, Litsanov B, Bott M, Wiechert W, Oldiges M. Biobasierte Produktion von organischen Säuren in Corynebacterium glutamicum: Stamm- und Prozesscharakterisierung im mL-Maßstab. CHEM-ING-TECH 2012. [DOI: 10.1002/cite.201250039] [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: 11/11/2022]
|
8
|
Eggeling L, Binder S, Schendzielorz G, Bott M. Optische Nanosensoren für Metabolit-Monitoring in der mikrobiellen Biotechnologie. CHEM-ING-TECH 2012. [DOI: 10.1002/cite.201250398] [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: 11/11/2022]
|
9
|
Siedler S, Bringer S, Bott M. Optimierung des Produkt-zu-Cosubstrat-Verhältnisses in einer reduzierenden Ganzzell-Biotransformation mit Escherichia coli. CHEM-ING-TECH 2012. [DOI: 10.1002/cite.201250258] [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: 11/11/2022]
|
10
|
Dobler N, Bott M, Polen T. Dynamische Kontrolle der Genexpression zur Steigerung der Lysinbildung in Corynebacterium glutamicum. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050282] [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: 11/07/2022]
|
11
|
Litsanov B, Brocker M, Bott M. Succinat-Produktion mit Corynebacterium glutamicum. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050420] [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: 11/06/2022]
|
12
|
Schweikert S, Polen T, Bringer-Meyer S, Bott M. Physiologie und Regulation des Zuckerkatabolismus in Gluconobacter oxydans. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050453] [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: 11/10/2022]
|
13
|
Gajewski BJ, Lee R, Bott M, Piamjariyakul U, Taunton RL. On estimating the distribution of data envelopment analysis efficiency scores: an application to nursing homes’ care planning process. J Appl Stat 2009. [DOI: 10.1080/02664760802552986] [Citation(s) in RCA: 5] [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: 10/21/2022]
|
14
|
Hanke T, Bringer S, Sahm H, Bott M. Establishment of oligonucleotide-based DNA microarrays of the Gluconobacter oxydans 621H genome: first results on the influence of pH and oxygen on the transcriptome. CHEM-ING-TECH 2009. [DOI: 10.1002/cite.200990081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
15
|
Litsanov B, Brocker M, Bott M. Succinat-Produktion mit Corynebacterium glutamicum. CHEM-ING-TECH 2009. [DOI: 10.1002/cite.200950198] [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: 11/07/2022]
|
16
|
Abstract
The Omnibus Budget Reconciliation Act of 1987 required nursing facilities to complete a standardized comprehensive assessment known as the Resident Assessment Instrument (RAI) and to formulate a plan of care from the RAI to guide nursing care. The purpose of this retrospective case study was to examine the issues around the translation of nursing facility resident care plans to documents that guide daily care. Data were obtained by auditing 96 resident care plans in 10 nursing facilities in two states. Despite the importance of the resident plan of care, the audit revealed the provider approaches to resident problems varied appreciably in nursing facilities. The results of this study support the need for further research to assist in the development and implementation of strategies in nursing facilities that focus on standardized practices. Consistent systems can be promoted that translate the resident care plan into daily practice.
Collapse
|
17
|
Bott M, Behrang-Nia M, Klimpe S, Werhahn K. Are spacial extension and recruitment of motor cortical inhibition related? Evidence using transcranial magnetic stimulation. Clin Neurophysiol 2007. [DOI: 10.1016/j.clinph.2006.11.048] [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: 10/23/2022]
|
18
|
Klimpe S, Behrang-Nia M, Bott M, Werhahn K. Recruitment of motor cortical excitability in untreated patients with epilepsy. Clin Neurophysiol 2007. [DOI: 10.1016/j.clinph.2006.11.140] [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: 11/29/2022]
|
19
|
Behrang-Nia M, Behrang-Nia M, Bott M, Klimpe S, Werhahn K. Analysis of correlation between the recruitment of excitation and inhibition in the motor cortex. Clin Neurophysiol 2007. [DOI: 10.1016/j.clinph.2006.11.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
20
|
Bott M, Behrang-Nia M, Klimpe S, Werhahn KJ. Are spacial extension and recruitment of motor cortical inhibition related? Evidence using transcranial magnetic stimulation. KLIN NEUROPHYSIOL 2006. [DOI: 10.1055/s-2006-939110] [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]
|
21
|
Behrang-Nia M, Behrang-Nia M, Bott M, Klimpe S, Werhahn KJ. Analysis of correlation between the recruitment of excitation and inhibition in the motor cortex. KLIN NEUROPHYSIOL 2006. [DOI: 10.1055/s-2006-939098] [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]
|
22
|
Klimpe S, Behrang-Nia M, Bott M, Werhahn K. Recruitment of motor cortical excitability in untreated patients with epilepsy. KLIN NEUROPHYSIOL 2006. [DOI: 10.1055/s-2006-939202] [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]
|
23
|
Zelić B, Gerharz T, Bott M, Vasić-Rački Đ, Wandrey C, Takors R. Fed-Batch Process for Pyruvate Production by Recombinant Escherichia coli YYC202 Strain. Eng Life Sci 2003. [DOI: 10.1002/elsc.200301756] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
24
|
Lange C, Rittmann D, Wendisch VF, Bott M, Sahm H. Global expression profiling and physiological characterization of Corynebacterium glutamicum grown in the presence of L-valine. Appl Environ Microbiol 2003; 69:2521-32. [PMID: 12732517 PMCID: PMC154540 DOI: 10.1128/aem.69.5.2521-2532.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [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] Open
Abstract
Addition of L-valine (50 to 200 mM) to glucose minimal medium had no effect on the growth of wild-type Corynebacterium glutamicum ATCC 13032 but inhibited the growth of the derived valine production strain VAL1 [13032 DeltailvA DeltapanBC(pJC1ilvBNCD)] in a concentration-dependent manner. In order to explore this strain-specific valine effect, genomewide expression profiling was performed using DNA microarrays, which showed that valine caused an increased ilvBN mRNA level in VAL1 but not in the wild type. This unexpected result was confirmed by an increased cellular level of the ilvB protein product, i.e., the large subunit of acetohydroxyacid synthase (AHAS), and by an increased AHAS activity of valine-treated VAL1 cells. The conclusion that valine caused the limitation of another branched-chain amino acid was confirmed by showing that high concentrations of L-isoleucine could relieve the valine effect on VAL1 whereas L-leucine had the same effect as valine. The valine-caused isoleucine limitation was supported by the finding that the inhibitory valine effect was linked to the ilvA deletion that results in isoleucine auxotrophy. Taken together, these results implied that the valine effect is caused by competition for uptake of isoleucine by the carrier BrnQ, which transports all branched-chained amino acids. Indeed, valine inhibition could also be relieved by supplementing VAL1 with the dipeptide isoleucyl-isoleucine, which is taken up by a dipeptide transport system rather than by BrnQ. Interestingly, addition of external valine stimulated valine production by VAL1. This effect is most probably due to a reduced carbon usage for biomass production and to the increased expression of ilvBN, indicating that AHAS activity may still be a limiting factor for valine production in the VAL1 strain.
Collapse
Affiliation(s)
- C Lange
- Institut für Biotechnologie 1, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | | | | | | | | |
Collapse
|
25
|
Schaffer S, Weil B, Nguyen VD, Dongmann G, Günther K, Nickolaus M, Hermann T, Bott M. A high-resolution reference map for cytoplasmic and membrane-associated proteins of Corynebacterium glutamicum. Electrophoresis 2001; 22:4404-22. [PMID: 11824608 DOI: 10.1002/1522-2683(200112)22:20<4404::aid-elps4404>3.0.co;2-2] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [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: 02/01/2023]
Abstract
We present a high-resolution reference map for soluble proteins obtained from Corynebacterium glutamicum cells grown in glucose minimal medium. The analysis window covers the pl range from 4-6 and the molecular mass range from 5-100 kDa. Using overlapping narrow immobilized pH gradients for isoelectric focusing, 970 protein spots were detected after second-dimensional separation on SDS-polyacrylamide gels and colloidal Coomassie-staining. By tryptic peptide mass fingerprinting 169 protein spots were identified, representing 152 different proteins including many enzymes involved in central metabolism (18), amino acid biosynthesis (24) and nucleotide biosynthesis (11). Thirty-five of the identified proteins have no known function. A comparison of the observed and the expected physicochemical properties of the identified proteins indicated that nine proteins were covalently modified, since variants with apparently identical molecular mass, but differing pl were detected. The N-termini of eight proteins were determined by post-source decay (PSD) analysis of selected peptides. In addition to the soluble proteins, a map of the membrane-bound proteins within the pl range 4-7 is presented, which contains 660 protein spots, 22 of which were identified, representing 13 different proteins.
Collapse
Affiliation(s)
- S Schaffer
- Institut für Biotechnologie 1, Forschungszentrum Jülich, Germany
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Meyer M, Dimroth P, Bott M. Catabolite repression of the citrate fermentation genes in Klebsiella pneumoniae: evidence for involvement of the cyclic AMP receptor protein. J Bacteriol 2001; 183:5248-56. [PMID: 11514506 PMCID: PMC95405 DOI: 10.1128/jb.183.18.5248-5256.2001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [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] Open
Abstract
Klebsiella pneumoniae is able to grow anaerobically with citrate as a sole carbon and energy source by a fermentative pathway involving the Na(+)-dependent citrate carrier CitS, citrate lyase, and oxaloacetate decarboxylase. The corresponding genes are organized in the divergent citC and citS operons, whose expression is strictly dependent on the citrate-sensing CitA-CitB two-component system. Evidence is provided here that the citrate fermentation genes are subject to catabolite repression, since anaerobic cultivation with a mixture of citrate and glucose or citrate and gluconate resulted in diauxic growth. Glucose, gluconate, and also glycerol decreased the expression of a chromosomal citS-lacZ fusion by 60 to 75%, whereas a direct inhibition of the citrate fermentation enzymes was not observed. The purified cyclic AMP (cAMP) receptor protein (CRP) of K. pneumoniae bound to two sites in the citC-citS intergenic region, which were centered at position -41.5 upstream of the citC and citS transcriptional start sites. Binding was apparently stimulated by the response regulator CitB. These data indicate that catabolite repression of the citrate fermentation genes is exerted by CRP and that in the absence of repressing carbon sources the cAMP-CRP complex serves to enhance the basal, CitB-dependent transcription level.
Collapse
Affiliation(s)
- M Meyer
- Institut für Mikrobiologie, Eidgenössische Technische Hochschule Zürich, 8092 Zürich, Switzerland
| | | | | |
Collapse
|
27
|
Abstract
We describe the discovery and developmental features of a Helicosporidium sp. isolated from the black fly Simulium jonesi. Morphologically, the helicosporidia are characterized by a distinct cyst stage that encloses three ovoid cells and a single elongate filamentous cell. Bioassays have demonstrated that the cysts of this isolate infect various insect species, including the lepidopterans, Helicoverpa zea, Galleria mellonella, and Manduca sexta, and the dipterans, Musca domestica, Aedes taeniorhynchus, Anopheles albimanus, and An. quadrimaculatus. The cysts attach to the insect peritrophic matrix prior to dehiscence, which releases the filamentous cell and the three ovoid cells. The ovoid cells are short-lived in the insect gut with infection mediated by the penetration of the filamentous cell into the host. Furthermore, these filamentous cells are covered with projections that anchor them to the midgut lining. Unlike most entomopathogenic protozoa, this Helicosporidium sp. can be propagated in simple nutritional media under defined in vitro conditions, providing a system to conduct detailed analysis of the developmental biology of this poorly known taxon. The morphology and development of the in vitro produced cells are similar to that reported for the achorophyllic algae belonging to the genus Prototheca.
Collapse
Affiliation(s)
- D G Boucias
- Department of Entomology and Nematology, University of Florida, Gainesville 32611, USA.
| | | | | | | |
Collapse
|
28
|
Hermann T, Pfefferle W, Baumann C, Busker E, Schaffer S, Bott M, Sahm H, Dusch N, Kalinowski J, Pühler A, Bendt AK, Krämer R, Burkovski A. Proteome analysis of Corynebacterium glutamicum. Electrophoresis 2001; 22:1712-23. [PMID: 11425227 DOI: 10.1002/1522-2683(200105)22:9<1712::aid-elps1712>3.0.co;2-g] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [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: 11/09/2022]
Abstract
By the use of different Corynebacterium glutamicum strains more than 1.4 million tons of amino acids, mainly L-glutamate and L-lysine, are produced per year. A project was started recently to elucidate the complete DNA sequence of this bacterium. In this communication we describe an approach to analyze the C. glutamicum proteome, based on this genetic information, by a combination of two-dimensional (2-D) gel electrophoresis and protein identification via microsequencing or mass spectrometry. We used these techniques to resolve proteins of C. glutamicum with the aim to establish 2-D protein maps as a tool for basic microbiology and for strain improvement. In order to analyze the C. glutamicum proteome, methods were established to fractionate the C. glutamicum proteins according to functional entities, i.e., cytoplasm, membranes, and cell wall. Protein spots of the cytoplasmic and membrane fraction were identified by N-terminal sequencing, immunodetection, matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray ionization-mass spectrometry (ESI-MS). Additionally, a protocol to analyze proteins secreted by C. glutamicum was established. Approximately 40 protein spots were observed on silver-stained 2-D gels, 12 of which were identified.
Collapse
Affiliation(s)
- T Hermann
- Degussa-Hüls AG, Halle/Westfalen, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Niebisch A, Bott M. Molecular analysis of the cytochrome bc1-aa3 branch of the Corynebacterium glutamicum respiratory chain containing an unusual diheme cytochrome c1. Arch Microbiol 2001; 175:282-94. [PMID: 11382224 DOI: 10.1007/s002030100262] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.6] [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: 10/27/2022]
Abstract
In this work, the genes for cytochrome aa3 oxidase and the cytochrome bc1 complex in the gram-positive soil bacterium Corynebacterium glutamicum were identified. The monocistronic ctaD gene encoded a 65-kDa protein with all features typical for subunit I of cytochrome aa3 oxidases. A ctaD deletion mutant lacked the characteristic 600 nm peak in redox difference spectra, and growth in glucose minimal medium was strongly impaired. The genes encoding subunit III of cytochrome aa3 (ctaE) and the three characteristic subunits of the cytochrome bc1 complex (qcrABC) were clustered in the order ctaE-qcrCAB. Analysis of the deduced primary structures revealed a number of unusual features: (1) cytochrome c1 (QcrC, 30 kDa) contained two Cys-X-X-Cys-His motifs for covalent heme attachment, indicating that it is a diheme c-type cytochrome; (2) the 'Rieske' iron-sulphur protein (QcrA, 45 kDa) contained three putative transmembrane helices in the N-terminal region rather than only one; and (3) cytochrome b (QcrB, 60 kDa) contained, in addition to the conserved part with eight transmembrane helices, a C-terminal extension of about 120 amino acids, which presumably is located in the cytoplasm. Staining of C. glutamicum proteins for covalently bound heme indicated the presence of a single, membrane-bound c-type cytochrome with an apparent molecular mass of about 31 kDa. Since this protein was missing in a qcrCAB deletion mutant, it most likely corresponds to cytochrome c1. Similar to the deltactaD mutant, the deltaqcrCAB mutant showed strongly impaired growth in glucose minimal medium, which indicates that the bc1-aa3 pathway is the main route of respiration under these conditions.
Collapse
Affiliation(s)
- A Niebisch
- Institut für Biotechnologie 1, Forschungszentrum Jülich GmbH, Germany
| | | |
Collapse
|
30
|
Abstract
The gamma-subunit of citrate lyase (EC 4.1.3.6) contains the prosthetic group 2'-(5"-phosphoribosyl)-3'-dephospho-CoA and serves as an acyl carrier protein (ACP). We recently showed that in Escherichia coli the proteins CitG and CitX are essential for holo-ACP synthesis and provided evidence that CitG catalyzes the formation of a prosthetic group precursor from ATP and dephospho-CoA, which is subsequently attached via phosphodiester linkage to apo-ACP by CitX. Here we prove that CitG indeed catalyzes the conversion of ATP and dephospho-CoA to adenine and 2'-(5"-triphosphoribosyl)-3'-dephospho-CoA, the predicted precursor of the prosthetic group. Furthermore, this precursor was transferred by CitX to apo-ACP, yielding holo-ACP. Thus, our proposed mechanism for holo-ACP synthesis could be verified.
Collapse
Affiliation(s)
- K Schneider
- Institut für Mikrobiologie, Eidgenössische Technische Hochschule Zürich, Switzerland
| | | | | |
Collapse
|
31
|
Abstract
Citrate lyase (EC 4.1.3.6) catalyzes the cleavage of citrate to acetate and oxaloacetate and is composed of three subunits (alpha, beta, and gamma). The gamma-subunit serves as an acyl carrier protein (ACP) and contains the prosthetic group 2'-(5' '-phosphoribosyl)-3'-dephospho-CoA, which is attached via a phosphodiester linkage to serine-14 in the enzyme from Klebsiella pneumoniae. In this work, we demonstrate by genetic and biochemical studies with citrate lyase of Escherichia coli and K. pneumoniae that the conversion of apo-ACP into holo-ACP is dependent on the two proteins, CitX (20 kDa) and CitG (33 kDa). In the absence of CitX, only apo-ACP was synthesized in vivo, whereas in the absence of CitG, an adenylylated ACP was produced, with the AMP residue attached to serine-14. The adenylyltransferase activity of CitX could be verified in vitro with purified CitX and apo-ACP plus ATP as substrates. Besides ATP, CTP, GTP, and UTP also served as nucleotidyl donors in vitro, showing that CitX functions as a nucleotidyltransferase. The conversion of apo-ACP into holo-ACP was achieved in vitro by incubation of apo-ACP with CitX, CitG, ATP, and dephospho-CoA. ATP could not be substituted with GTP, CTP, UTP, ADP, or AMP. In the absence of CitG or dephospho-CoA, AMP-ACP was formed. Remarkably, it was not possible to further convert AMP-ACP to holo-ACP by subsequent incubation with CitG and dephospho-CoA. This demonstrates that AMP-ACP is not an intermediate during the conversion of apo- into holo-ACP, but results from a side activity of CitX that becomes effective in the absence of its natural substrate. Our results indicate that holo-ACP formation proceeds as follows. First, a prosthetic group precursor [presumably 2'-(5' '-triphosphoribosyl)-3'-dephospho-CoA] is formed from ATP and dephospho-CoA in a reaction catalyzed by CitG. Second, holo-ACP is formed from apo-ACP and the prosthetic group precursor in a reaction catalyzed by CitX.
Collapse
Affiliation(s)
- K Schneider
- Institut für Mikrobiologie, Eidgenössische Technische Hochschule Zürich, Switzerland
| | | | | |
Collapse
|
32
|
Bott M. The impact of cultural values on patient education for the elderly. CANNT J 2000; 10:39-43, 46-50; quiz 44-5, 51-2. [PMID: 15719604] [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] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Little literature has examined the interaction of culture and patient education with specific reference to the elderly. It is necessary for nurses to develop a respectful understanding of their patient's culture in order to provide meaningful and relevant patient education. Understanding of cultural differences is especially important when educating elderly immigrants, as many elderly retain significant aspects of their native cultural traditions and may be slower to acculturate to Western cultural values. This paper will outline a number of assessment parameters and educational strategies necessary for nurses to begin to provide culturally sensitive patient education for elderly patients within the nephrology setting.
Collapse
Affiliation(s)
- M Bott
- Community Nephrology Initiative, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario
| |
Collapse
|
33
|
Kaspar S, Perozzo R, Reinelt S, Meyer M, Pfister K, Scapozza L, Bott M. The periplasmic domain of the histidine autokinase CitA functions as a highly specific citrate receptor. Mol Microbiol 1999; 33:858-72. [PMID: 10447894 DOI: 10.1046/j.1365-2958.1999.01536.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [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: 11/20/2022]
Abstract
The two-component regulatory system CitA/CitB is essential for induction of the citrate fermentation genes in Klebsiella pneumoniae. CitA represents a membrane-bound sensor kinase consisting of a periplasmic domain flanked by two transmembrane helices, a linker domain and the conserved kinase or transmitter domain. A fusion protein (MalE-CitAC) composed of the maltose-binding protein and the CitA kinase domain (amino acids 327-547) showed constitutive autokinase activity and transferred the gamma-phosphate group of ATP to its cognate response regulator CitB. The autokinase activity of CitA was abolished by an H350L exchange, and phosphorylation of CitB was inhibited by a D56N exchange, indicating that H-350 and D-56 represent the phosphorylation sites of CitA and CitB respectively. In the presence of ATP, CitB-D56N formed a stable complex with MalE-CitAC. To analyse the sensory properties of CitA, the periplasmic domain (amino acids 45-176) was overproduced as a soluble, cytoplasmic protein with a C-terminally attached histidine tag (CitAPHis). Purified CitAPHis bound citrate, but none of the other tri- and dicarboxylates tested, with high affinity (KD approximately 5 microM at pH 7) in a 1:1 stoichiometry. As shown by isothermal titration calorimetry, the binding reaction was driven by the enthalpy change (DeltaH = -76.3 kJ mol-1), whereas the entropy change was opposed (-TDeltaS = + 46.3 kJ mol-1). The pH dependency of the binding reaction indicated that the dianionic form H-citrate2- is the citrate species recognized by CitAPHis. In the presence of Mg2+ ions, the dissociation constant increased significantly, suggesting that the Mg-citrate complex is not bound by CitAPHis. This work defines the periplasmic domain of CitA as a highly specific citrate receptor and elucidates the binding characteristics of CitAPHis.
Collapse
Affiliation(s)
- S Kaspar
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, Schmelzbergstrasse 7, CH-8092 Zürich, Switzerland
| | | | | | | | | | | | | |
Collapse
|
34
|
Steuber J, Krebs W, Bott M, Dimroth P. A membrane-bound NAD(P)+-reducing hydrogenase provides reduced pyridine nucleotides during citrate fermentation by Klebsiella pneumoniae. J Bacteriol 1999; 181:241-5. [PMID: 9864336 PMCID: PMC103555 DOI: 10.1128/jb.181.1.241-245.1999] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [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] Open
Abstract
During anaerobic growth of Klebsiella pneumoniae on citrate, 9.4 mmol of H2/mol of citrate (4-kPa partial pressure) was formed at the end of growth besides acetate, formate, and CO2. Upon addition of NiCl2 (36 microM) to the growth medium, hydrogen formation increased about 36% to 14.8 mmol/mol of citrate (6 kPa), and the cell yield increased about 15%. Cells that had been harvested and washed under anoxic conditions exhibited an H2-dependent formation of NAD(P)H in vivo. The reduction of internal NAD(P)+ was also achieved by the addition of formate. In crude extracts, the H2:NAD+ oxidoreductase activity was 0.13 micromol min-1 mg-1, and 76% of this activity was found in the washed membrane fraction. The highest specific activities of the membrane fraction were observed in 50 mM potassium phosphate, with 1.6 micromol of NADPH formed min-1 mg-1 at pH 7.0 and 1.7 micromol of NADH formed min-1 mg-1 at pH 9.5. In the presence of the protonophore carbonyl cyanide m-chlorophenylhydrazone and the Na+/H+ antiporter monensin, the H2-dependent reduction of NAD+ by membrane vesicles decreased only slightly (about 16%). The NADP+- or NAD+-reducing hydrogenases were solubilized from the membranes with the detergent lauryldimethylamine-N-oxide or Triton X-100. NAD(P)H formation with H2 as electron donor, therefore, does not depend on an energized state of the membrane. It is proposed that hydrogen which is formed by K. pneumoniae during citrate fermentation is recaptured by a novel membrane-bound, oxygen-sensitive H2:NAD(P)+ oxidoreductase that provides reducing equivalents for the synthesis of cell material.
Collapse
Affiliation(s)
- J Steuber
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, ETH-Zentrum, CH-8092 Zürich, Switzerland
| | | | | | | |
Collapse
|
35
|
Pos KM, Dimroth P, Bott M. The Escherichia coli citrate carrier CitT: a member of a novel eubacterial transporter family related to the 2-oxoglutarate/malate translocator from spinach chloroplasts. J Bacteriol 1998; 180:4160-5. [PMID: 9696764 PMCID: PMC107412 DOI: 10.1128/jb.180.16.4160-4165.1998] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [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: 11/20/2022] Open
Abstract
Under anoxic conditions in the presence of an oxidizable cosubstrate such as glucose or glycerol, Escherichia coli converts citrate to acetate and succinate. Two enzymes are specifically required for the fermentation of the tricarboxylic acid, i.e., a citrate uptake system and citrate lyase. Here we report that the open reading frame (designated citT) located at 13.90 min on the E. coli chromosome between rna and the citrate lyase genes encodes a citrate carrier. E. coli transformed with a plasmid expressing citT was capable of aerobic growth on citrate, which provides convincing evidence for a function of CitT as a citrate carrier. Transport studies with cell suspensions of the transformed strain indicated that CitT catalyzes a homologous exchange of citrate or a heterologous exchange against succinate, fumarate, or tartrate. Since succinate is the end product of citrate fermentation in E. coli, it is likely that CitT functions in vivo as a citrate/succinate antiporter. Analysis of the primary sequence showed that CitT (487 amino acids, 53.1 kDa) is a highly hydrophobic protein with 12 putative transmembrane helices. Sequence comparisons revealed that CitT is related to the 2-oxoglutarate/malate translocator (SODiT1 gene product) from spinach chloroplasts and five bacterial gene products, none of which has yet been functionally characterized. It is suggested that the E. coli CitT protein is a member of a novel family of eubacterial transporters involved in the transport of di- and tricarboxylic acids.
Collapse
Affiliation(s)
- K M Pos
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland
| | | | | |
Collapse
|
36
|
Bott M. Embedded nursing practice: a case study. J CANNT 1998; 7:25-6. [PMID: 9460362] [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] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nurses' utilization of case study analysis often focuses on medically-based knowledge which is intertwined within our daily practice. Reflection on nurse-patient interactions with nursing theory as the analytic tool is infrequently undertaken. The case study analysis presented within this paper analyzes an exemplar utilizing the theoretical works of Patricia Benner.
Collapse
Affiliation(s)
- M Bott
- Toronto Community Care Access Centre, Ontario
| |
Collapse
|
37
|
Bott M, Pfister K, Burda P, Kalbermatter O, Woehlke G, Dimroth P. Methylmalonyl-CoA decarboxylase from Propionigenium modestum--cloning and sequencing of the structural genes and purification of the enzyme complex. Eur J Biochem 1997; 250:590-9. [PMID: 9428714 DOI: 10.1111/j.1432-1033.1997.0590a.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Methylmalonyl-CoA decarboxylase catalyses the only energy-conserving step during succinate fermentation by Propionigenium modestum: the decarboxylation of (S)-methylmalonyl-CoA to propionyl-CoA is coupled to the vectorial transport of Na+ across the cytoplasmic membrane, thereby creating a sodium ion motive force that is used for ATP synthesis. By taking advantage of the sequence similarity between the beta-subunits of other Na+-transport decarboxylases, a portion of the P. modestum beta-subunit gene was amplified by PCR with degenerated primers. The cloned PCR product then served as homologous probe for cloning suitable fragments from genomic DNA. Sequence analysis of a 3.7-kb region identified four genes which probably form a transcriptional unit, mmdADCB. Remarkably, a mmdE gene which is present in the homologous mmdADECB cluster from Veillonella parvula and encodes the 6-kDa epsilon-subunit, is missing in P. modestum. By sequence comparisons, the following functions could be assigned to the P. modestum proteins: MmdA (56.1 kDa; alpha-subunit), carboxyltransferase; MmdB (41.2 kDa; beta-subunit), carboxybiotin-carrier-protein decarboxylase; MmdC (13.1 kDa; gamma-subunit), biotin carrier protein. MmdD (14.2 kDa; delta-subunit) presumably is essential for the assembly of the complex, as shown for the corresponding V. parvula protein. Methylmalonyl-CoA decarboxylase was solubilized from membranes of P. modestum with n-dodecylmaltoside and enriched 15-fold by affinity chromatography on monomeric avidin resin. The purified protein was composed of four subunits, three of which were identified by N-terminal sequence analysis as MmdA, MmdD, and MmdC. The purified enzyme exhibited a specific activity of up to 25 U/mg protein and an apparent Km value for (S)-methylmalonyl-CoA of approximately 12 microM. Compared to the five-subunit complex of V. parvula, the four-subunit enzyme of P. modestum appeared to be more labile, presumably a consequence of the lack of the epsilon-subunit.
Collapse
Affiliation(s)
- M Bott
- Mikrobiologisches Institut der Eidgenössischen Technischen Hochschule Zürich, Switzerland
| | | | | | | | | | | |
Collapse
|
38
|
Affiliation(s)
- L M Connelly
- Department of Nursing Science, Army Medical Department Center & School, San Antonio, TX., USA
| | | | | | | |
Collapse
|
39
|
Meyer M, Dimroth P, Bott M. In vitro binding of the response regulator CitB and of its carboxy-terminal domain to A + T-rich DNA target sequences in the control region of the divergent citC and citS operons of Klebsiella pneumoniae. J Mol Biol 1997; 269:719-31. [PMID: 9223636 DOI: 10.1006/jmbi.1997.1076] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [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: 02/04/2023]
Abstract
The genes specifically required for citrate fermentation in Klebsiella pneumoniae form a cluster on the chromosome consisting of two divergently transcribed groups, citCDEFG and citS-oadGAB-citAB. Northern blot analyses described here and elsewhere indicate that each group forms an operon. The transcriptional start sites of citC and citS, which were mapped in this work by primer extension, are separated by a stretch of 193 bp with an extraordinary high A + T content of 67%. Expression of the citrate fermentation genes was recently shown to be positively controlled by a two-component signal transduction system encoded by the promoter-distal genes of the citS operon, citA (sensor kinase) and citB (response regulator). As a first step towards the functional characterization of CitB, we analysed its DNA-binding properties. To this end, the entire CitB, its N-terminal receiver domain (CitBN), and its C-terminal output domain (CitBC), all modified by a (His)6-tag, were purified. CitB(His) and CitBN(His) could be phosphorylated either with acetylphosphate or with ATP plus MalE-CitAC. The latter protein contains the kinase domain of CitA fused to the C terminus of the maltose-binding protein. Upon phosphorylation, CitB(His) became more resistant towards limited proteolysis by trypsin, reflecting substantial changes in tertiary structure. In gel retardation assays, CitB(His) bound specifically to the citC-citS intergenic region. The retardation pattern changed significantly upon phosphorylation and the apparent binding affinity increased 10 to 100-fold. Depending on the protein concentration, four different phospho-CitB(His)-DNA complexes could be resolved, suggesting the presence of multiple binding sites between citC and citS. DNase I footprints revealed two protected regions extending maximally from -55 to -89 relative to the citS transcription start and from -50 to -96 relative to the citC transcription start. Gel retardation and DNase I footprint assays with CitBC(His) showed that the C-terminal domain is sufficient for specific DNA binding. Since its properties were similar to that of unphosphorylated CitB(His), an essential role of the N-terminal receiver domain in high-affinity DNA binding was indicated. The positions of the binding sites for CitB and of putative recognition sequences for the cAMP receptor protein suggested a model for the interaction of these activators with RNA polymerase.
Collapse
Affiliation(s)
- M Meyer
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, Zürich, Switzerland
| | | | | |
Collapse
|
40
|
|
41
|
Bott M. Anaerobic citrate metabolism and its regulation in enterobacteria. Arch Microbiol 1997; 167:78-88. [PMID: 9133329] [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: 02/04/2023]
Abstract
Several species of enterobacteria are able to utilize citrate as carbon and energy source. Under oxic conditions in the presence of a functional tricarboxylic acid cycle, growth on this compound solely depends on an appropriate transport system. During anaerobiosis, when 2-oxoglutarate dehydrogenase is repressed, some species such as Klebsiella pneumoniae and Salmonella typhimurium, but not Escherichia coli, are capable of growth on citrate by a Na+-dependent pathway forming acetate, formate, and CO2 as products. During the last decade, several novel features associated with this type of fermentation have been discovered in K. pneumoniae. The biotin protein oxaloacetate decarboxylase, one of the key enzymes of the pathway besides citrate lyase, is a Na+ pump. Recently it has been shown that the proton required for the decarboxylation of carboxybiotin is taken up from the side to which Na+ ions are pumped, and a membrane-embedded aspartate residue that is probably involved both in Na+ and in H+ transport was identified. The Na+ gradient established by oxaloacetate decarboxylase drives citrate uptake via CitS, a homodimeric carrier protein with a simultaneous-type reaction mechanism, and NADH formation by reversed electron transfer involving formate dehydrogenase, quinone, and a Na+-dependent NADH:quinone oxidoreductase. All enzymes specifically required for citrate fermentation are induced under anoxic conditions in the presence of citrate and Na+ ions. The corresponding genes form a cluster on the chromosome and are organized as two divergently transcribed operons. Their co-ordinate expression is dependent on a two-component system consisting of the sensor kinase CitA and the response regulator CitB. The citAB genes are part of the cluster and are positively autoregulated. In addition to CitA/CitB, the cAMP receptor protein (Crp) is involved in the regulation of the citrate fermentation enzymes, subjecting them to catabolite repression.
Collapse
Affiliation(s)
- M Bott
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, ETH-Zentrum, Schmelzbergstrasse 7, CH-8092 Zürich, Switzerland.
| |
Collapse
|
42
|
Hohage M, Bott M, Morgenstern M, Zhang Z, Michely T, Comsa G. Atomic processes in low temperature Pt-dendrite growth on Pt(111). Phys Rev Lett 1996; 76:2366-2369. [PMID: 10060679 DOI: 10.1103/physrevlett.76.2366] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
43
|
Bott M, Hohage M, Morgenstern M, Michely T, Comsa G. New approach for determination of diffusion parameters of adatoms. Phys Rev Lett 1996; 76:1304-1307. [PMID: 10061687 DOI: 10.1103/physrevlett.76.1304] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
44
|
Abstract
Quality patient care is best provided by competent clinical staff members who are committed to their work, organizational values, and goals, and who maintain employment over time. Shared governance has provided the framework for clinical nurses to become more committed to their practice through decision making and to assume accountability for the outcomes of their decisions. At a tertiary teaching facility, shared governance resulted in increased job satisfaction, commitment, and retention among staff nurses. The authors describe the journey from creation of the shared governance vision to reality, and the impact of the changes.
Collapse
|
45
|
Abstract
Three enzymes are specifically required for uptake and catabolism of citrate by Klebsiella pneumoniae under anaerobic conditions: a Na+ -dependent citrate carrier (CitS), citrate lyase (CitDEF), and the Na+ pump oxaloacetate decarboxylase (OadGAB). The corresponding genes are clustered on the chromosome, with the citCDEFG genes located upstream and divergent to the citS-oadGAB genes. We found that expression of citS from its native promoter in Escherichia coli requires the DNA region downstream of oadB. Nucleotide sequence analysis of this region revealed the presence of two adjacent genes, citA and citB. By sequence similarity, the predicted CitA and CitB proteins were identified as members of the two-component regulatory systems. The sensor kinase CitA contained, in the N-terminal half, two putative transmembrane helices which enclosed a presumably periplasmic domain of about 130 amino acids. The C-terminal half of the response regulator CitB harboured a helix-turn-helix motif typical of DNA-binding proteins. K. pneumoniae citB null mutants were unable to grow anaerobically with citrate as the sole carbon and energy source (Cit- phenotype). When cultivated anaerobically with citrate plus glycerol, all of the citrate-specific fermentation enzymes were synthesized in the wild type, but not in the citB mutants. This showed that citS, oadGAB and citDEF required the CitB protein for expression and therefore are part of a regulon. In the wild type, synthesis of CitS, oxaloacetate decarboxylase and citrate lyase was dependent on the presence of citrate, sodium ions and a low oxygen tension. In a citA null mutant which expressed citB constitutively at high levels, none of these signals was required for the formation of the citrate fermentation enzymes. This result suggested that citrate, Na+, and oxygen exerted their regulatory effects via the CitA/CitB system. In the presence of these signals, the citAB gene products induced their own synthesis. The positive autoregulation occurred via co-transcription of citAB with citS and oadGAB.
Collapse
Affiliation(s)
- M Bott
- Mikrobiologisches Institut, Eidgenöessische Technische Hochschule, Zurich, Switzerland.
| | | | | |
Collapse
|
46
|
Spichiger UE, Citterio D, Bott M. Analyte-selective optode membranes and optical evaluation techniques: characterization of response behavior by ATR measurements. ACTA ACUST UNITED AC 1995. [DOI: 10.1117/12.221731] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
47
|
Bott M, Thöny-Meyer L, Loferer H, Rossbach S, Tully RE, Keister D, Appleby CA, Hennecke H. Bradyrhizobium japonicum cytochrome c550 is required for nitrate respiration but not for symbiotic nitrogen fixation. J Bacteriol 1995; 177:2214-7. [PMID: 7721713 PMCID: PMC176869 DOI: 10.1128/jb.177.8.2214-2217.1995] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [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
Bradyrhizobium japonicum possesses three soluble c-type cytochromes, c550, c552, and c555. The genes for cytochromes c552 (cycB) and c555 (cycC) were characterized previously. Here we report the cloning, sequencing, and mutational analysis of the cytochrome c550 gene (cycA). A B. japonicum mutant with an insertion in cycA failed to synthesize a 12-kDa c-type cytochrome. This protein was detectable in the cycA mutant complemented with cloned cycA, which proves that it is the cycA gene product. The cycA mutant, a cycB-cycC double mutant, and a cycA-cycB-cycC triple mutant elicited N2-fixing root nodules on soybean (Nod+ Fix+ phenotype); hence, none of these three cytochromes c is essential for respiration supporting symbiotic N2 fixation. However, cytochrome c550, in contrast to cytochromes c552 and c555, was shown to be essential for anaerobic growth of B. japonicum, using nitrate as the terminal electron acceptor.
Collapse
Affiliation(s)
- M Bott
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, Zürich, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
In the course of studies on anaerobic citrate metabolism in Klebsiella pneumoniae, the DNA region upstream of the gene for the sodium-dependent citrate carrier (citS) was investigated. Nucleotide sequence analysis revealed a cluster of five new genes that were oriented inversely to citS and probably form an operon. The genes were named citCDEFG. Based on known protein sequence data, the gene products derived from citD, citE and citF could be identified as the gamma-, beta-, and alpha-subunits of citrate lyase, respectively. This enzyme catalyses the cleavage of citrate to oxaloacetate and acetate. The gene product derived from citC (calculated M(r) 38,476) exhibited no obvious similarity to other proteins. In the presence of acetate and ATP, cell extracts from a citC-expressing Escherichia coli strain were able to reactivate purified citrate lyase from K. pneumoniae that had been inactivated by chemical deacetylation of the prosthetic group. This represents 5-phosphoribosyl-dephospho-acetyl-coenzyme A which is covalently bound to serine-14 of the acyl carrier protein (gamma-subunit). CitC was thus identified as acetate:SH-citrate lyase ligase. The function of the gene product derived from citG (M(r) 32,645) has not yet been identified. Expression of the citCDEFG gene cluster in E. coli led to the formation of citrate lyase which was active only in the presence of acetyl-coenzyme A, a compound known to substitute for the prosthetic group. These and other data strongly indicated that the enzyme synthesized in E. coli lacked its prosthetic group. Thus, additional genes besides citCDEFG appear to be required for the formation of holo-citrate lyase.
Collapse
Affiliation(s)
- M Bott
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, Zürich, Switzerland
| | | |
Collapse
|
49
|
Abstract
The sodium-ion-dependent citrate carrier of Klebsiella pneumoniae (CitS) was purified by means of bioengineerical methods. By fusing the biotin acceptor domain of the alpha-subunit of the oxaloacetate decarboxylase of K. pneumoniae to the C-terminus of CitS, purification of the carrier was achieved by use of a monomeric avidin-Sepharose column. Additionally, we were able to purify a CitS-protein with an N-terminal histidine-tag by immobilized metal chelate affinity chromatography (with Ni2(+)-nitrilotriacetic acid-(NTA-) resin). Both purified fusion proteins showed citrate transport activity after reconstitution into liposomes by the freeze/thaw/sonication procedure.
Collapse
Affiliation(s)
- K M Pos
- Mikrobiologisches Institut der Eidgenössischen Technischen Hochschule, ETH-Zentrum, Zürich, Switzerland
| | | | | |
Collapse
|
50
|
Loferer H, Bott M, Hennecke H. Bradyrhizobium japonicum TlpA, a novel membrane-anchored thioredoxin-like protein involved in the biogenesis of cytochrome aa3 and development of symbiosis. EMBO J 1993; 12:3373-83. [PMID: 8253065 PMCID: PMC413611 DOI: 10.1002/j.1460-2075.1993.tb06011.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.3] [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
We report the discovery of a bacterial gene, tlpA, that codes for a hitherto unknown type of thioredoxin-like protein. The gene was found in the course of studying a Tn5 insertion mutant of the soybean root nodule symbiont Bradyrhizobium japonicum. The TlpA protein shared up to 31% amino acid sequence identity with various eukaryotic and prokaryotic thioredoxins and protein disulfide isomerases, and possessed a characteristic active-site sequence, Trp-Cys-Val-Pro-Cys. In contrast to all members of the thioredoxin family known to date, TlpA was shown to be anchored to the cytoplasmic membrane by means of an N-terminal transmembrane domain, while the active site-containing part of the protein faced the periplasm. The tlpA mutant had a pleiotropic phenotype in that it was defective in the development of a nitrogen fixing endosymbiosis and exhibited a strongly decreased oxidase activity, as compared with the wild-type. Holocytochrome aa3 was spectroscopically undetectable in the mutant, whereas the apoprotein of subunit one (CoxA) of this oxidase was still synthesized and incorporated into the cytoplasmic membrane. Since cytochrome aa3 is not a prerequisite for the development of symbiosis, the results suggest that TlpA is involved in at least two independent cellular processes, one of which is an essential periplasmic step in the maturation of cytochrome aa3.
Collapse
Affiliation(s)
- H Loferer
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule, Zürich, Switzerland
| | | | | |
Collapse
|