Overexpression ofdnaK/dnaJandgroELConfers Freeze Tolerance toEscherichia coli

Chow, King-Chuen; Tung, Wai Lin

doi:10.1006/bbrc.1998.9766

Cited by 41 publications

(24 citation statements)

References 7 publications

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“…The importance of the role of DnaK/J at high temperatures is further supported by our observation that only these chaperones were essential for acquisition of thermotolerance. These results are consistent with the suggestion that DnaK/J have a greater role as molecular chaperones than GroES/EL (11,16).…”

Section: Discussionsupporting

confidence: 92%

“…Protein renaturation after cold shock and freezing seems to be more crucial to bacteria than during these stresses; therefore, the chaperones are more important in the recovery phase. In E. coli, it was also shown that it is mainly DnaK that allows cells to survive after freezing, as a dnaK mutant performed worse than a groEL mutant during recovery from this stress (11).…”

Section: Discussionmentioning

confidence: 99%

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GroES/GroEL and DnaK/DnaJ Have Distinct Roles in Stress Responses and during Cell Cycle Progression inCaulobacter crescentus

et al. 2006

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Misfolding and aggregation of protein molecules are major threats to all living organisms. Therefore, cells have evolved quality control systems for proteins consisting of molecular chaperones and proteases, which prevent protein aggregation by either refolding or degrading misfolded proteins. DnaK/DnaJ and GroES/ GroEL are the best-characterized molecular chaperone systems in bacteria. In Caulobacter crescentus these chaperone machines are the products of essential genes, which are both induced by heat shock and cell cycle regulated. In this work, we characterized the viabilities of conditional dnaKJ and groESL mutants under different types of environmental stress, as well as under normal physiological conditions. We observed that C. crescentus cells with GroES/EL depleted are quite resistant to heat shock, ethanol, and freezing but are sensitive to oxidative, saline, and osmotic stresses. In contrast, cells with DnaK/J depleted are not affected by the presence of high concentrations of hydrogen peroxide, NaCl, and sucrose but have a lower survival rate after heat shock, exposure to ethanol, and freezing and are unable to acquire thermotolerance. Cells lacking these chaperones also have morphological defects under normal growth conditions. The absence of GroE proteins results in long, pinched filamentous cells with several Z-rings, whereas cells lacking DnaK/J are only somewhat more elongated than normal predivisional cells, and most of them do not have Z-rings. These findings indicate that there is cell division arrest, which occurs at different stages depending on the chaperone machine affected. Thus, the two chaperone systems have distinct roles in stress responses and during cell cycle progression in C. crescentus.Caulobacter crescentus, an aquatic bacterium and a member of the ␣ subdivision of the Proteobacteria, produces two cell types: motile, DNA replication-quiescent "swarmer cells" and sessile, DNA replication-competent "stalked cells." The former are important for dispersion, and the latter are important for reproduction (65).Each motile swarmer cell has a single polar flagellum and several pili at one pole. CtrA, a DNA-binding response regulator that directly controls transcription of at least 95 genes in 55 operons (48), is present in swarmer cells, where it binds to the C. crescentus origin of replication and blocks replication initiation (61). Simultaneously, CtrA directly represses transcription of gcrA (35), ftsZ (44), and podJ (12), blocking the early steps in cell division and polar development. Swarmer cells undergo differentiation to stalked cells, during which the polar pili, flagellum, and chemotaxis apparatus are lost and are replaced by a stalk that grows at the pole previously occupied by the flagellum. Concurrent with the swarmer cell-stalked cell transition, CtrA is degraded (60), while DnaA levels increase (31). The presence of DnaA, not just the absence of CtrA, is required to trigger an increase in GcrA levels and start the next wave of cell cycle transcription, which includes exp...

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

GroES/GroEL and DnaK/DnaJ Have Distinct Roles in Stress Responses and during Cell Cycle Progression inCaulobacter crescentus

et al. 2006

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“…HSPs are commonly induced by multiple stresses and play an important role in withstanding and surviving harmful conditions (44). In L. lactis, the expression of DnaK is induced by heat, saline, and acid stresses (4,14,21,25,46), and it was reported previously that the in vitro overexpres-sion of DnaK conferred freeze tolerance to E. coli (8). Until now, cold induction of DnaK has been described only for Leuconostoc mesenteroides (43).…”

Section: Discussionmentioning

confidence: 99%

Adaptation to Cold and Proteomic Responses of the Psychrotrophic Biopreservative Lactococcus piscium Strain CNCM I-4031

Garnier

Matamoros

Chevret

et al. 2010

Appl Environ Microbiol

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There is considerable interest in the use of psychrotrophic bacteria for food biopreservation and in the understanding of cold adaptation mechanisms. The psychrotrophic biopreservative Lactococcus piscium strain CNCM I-4031 was studied for its growth behavior and proteomic responses after cold shock and during cold acclimation. Growth kinetics highlighted the absence of growth latency after cold shock, suggesting a very high promptness in cold adaptation, a behavior that has never been described before for lactic acid bacteria (LAB). A comparative proteomic analysis was applied with two-dimensional gel electrophoresis (2-DE), and upregulated proteins were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Both cold shock and cold acclimation triggered the upregulation of proteins involved in general and oxidative stress responses and fatty acid and energetic metabolism. However, 2-DE profiles and upregulated proteins were different under both conditions, suggesting a sequence of steps in cold adaptation. In addition, the major 7-kDa Csp protein was identified in the L. piscium CNCM I-4031 genome but was not cold regulated. The implication of the identified cold shock proteins and cold acclimation proteins in efficient cold adaptation, the possible regulation of a histidyl phosphocarrier protein, and the roles of a constitutive major 7-kDa Csp are discussed.Lactic acid bacteria (LAB) usually become the dominant flora during the storage of refrigerated preserved meat or fish products. Some of them have been widely described for their beneficial role in food preservation (42), and psychrotrophic strains present a real advantage for a biopreservation strategy (29). Matamoros et al. (35) previously isolated psychrotrophic lactic acid bacteria from seafood products and examined them for their ability to inhibit pathogenic and spoiling bacteria in a model medium. One of these strains, Lactococcus piscium CNCM I-4031, previously named EU2241, has been shown to extend the sensory shelf-life of vacuum-packed shrimp and cold-smoked salmon and to limit the development of Listeria monocytogenes, Staphylococcus aureus, and Brochothrix thermosphacta (12,13,34). This bacterium shows an uncommon temperature-related growth profile. Unlike most of the LAB, the growth of L. piscium CNCM I-4031 occurs from 0°C to 29°C, with an optimum at 26°C, and is inhibited at temperatures higher than 29°C, suggesting a specific cold adaptation behavior.Low temperatures usually result in a wide range of molecular and cellular disruptions: decreases in membrane fluidity and in enzymatic activity (Arrhenius), inefficient folding of some proteins, and increases in RNA and DNA secondary structures, leading to a decreased efficiency of transcription and translation (51). Cold environments are widespread on

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“…There is compelling evidence that HSPs participate in this so-called acquired tolerance (3)(4)(5), although which HSPs are critical and how they function remains a topic of active research and seems to differ for different organisms or cell types (6). In the hyperthermophilic archaeon Sulfolobus shibatae, which grows optimally at 83°C (7), acquired thermotolerance at lethal temperatures (Ͼ90°C) correlates with the increased synthesis of primarily two 60-kDa HSPs known as TF55 ␣ and ␤ (8-10).…”

mentioning

confidence: 99%

Intracellular localization of a group II chaperonin indicates a membrane-related function

Trent

Kagawa

Paavola

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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Chaperonins are protein complexes that are believed to function as part of a protein folding system in the cytoplasm of the cell. We observed, however, that the group II chaperonins known as rosettasomes in the hyperthermophilic archaeon Sulfolobus shibatae, are not cytoplasmic but membrane associated. This association was observed in cultures grown at 60°C and 76°C or heat-shocked at 85°C by using immunofluorescence microscopy and in thick sections of rapidly frozen cells grown at 76°C by using immunogold electron microscopy. We observed that increased abundance of rosettasomes after heat shock correlated with decreased membrane permeability at lethal temperature (92°C). This change in permeability was not seen in cells heat-shocked in the presence of the amino acid analogue azetidine 2-carboxylic acid, indicating functional protein synthesis influences permeability. Azetidine experiments also indicated that observed heat-induced changes in lipid composition in S. shibatae could not account for changes in membrane permeability. Rosettasomes purified from cultures grown at 60°C and 76°C or heat-shocked at 85°C bind to liposomes made from either the bipolar tetraether lipids of Sulfolobus or a variety of artificial lipid mixtures. The presence of rosettasomes did not significantly change the transition temperature of liposomes, as indicated by differential scanning calorimetry, or the proton permeability of liposomes, as indicated by pyranine fluorescence. We propose that these group II chaperonins function as a structural element in the natural membrane based on their intracellular location, the correlation between their functional abundance and membrane permeability, and their potential distribution on the membrane surface.

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Overexpression ofdnaK/dnaJandgroELConfers Freeze Tolerance toEscherichia coli

Cited by 41 publications

References 7 publications

GroES/GroEL and DnaK/DnaJ Have Distinct Roles in Stress Responses and during Cell Cycle Progression inCaulobacter crescentus

GroES/GroEL and DnaK/DnaJ Have Distinct Roles in Stress Responses and during Cell Cycle Progression inCaulobacter crescentus

Adaptation to Cold and Proteomic Responses of the Psychrotrophic Biopreservative Lactococcus piscium Strain CNCM I-4031

Intracellular localization of a group II chaperonin indicates a membrane-related function

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