Linear Correlation between Online Capacitance and Offline Biomass Measurement up to High Cell Densities in Escherichia coli Fermentations in a Pilot-Scale Pressurized Bioreactor

2011 ◽  
Vol 21 (2) ◽  
pp. 204-211 ◽  
Author(s):  
Ingo Knabben
Keyword(s):  
Escherichia Coli ◽  
Linear Correlation ◽  
Pilot Scale ◽  
High Cell ◽  
Cell Densities

scholarly journals Sociality in Escherichia coli: Enterochelin Is a Private Good at Low Cell Density and Can Be Shared at High Cell Density

2015 ◽  
Vol 197 (13) ◽  
pp. 2122-2128 ◽  
Author(s):  
Rebecca L. Scholz ◽  
E. Peter Greenberg
Keyword(s):  
Escherichia Coli ◽  
Cell Density ◽  
Iron Acquisition ◽  
Partial Privatization ◽  
High Cell ◽  
Wild Type ◽  
Content Type ◽  
Cell Densities ◽  
The Cost ◽  
Low Cell Density

ABSTRACTMany bacteria produce secreted iron chelators called siderophores, which can be shared among cells with specific siderophore uptake systems regardless of whether the cell produces siderophores. Sharing secreted products allows freeloading, where individuals use resources without bearing the cost of production. Here we show that theEscherichia colisiderophore enterochelin is not evenly shared between producers and nonproducers. Wild-typeEscherichia coligrows well in low-iron minimal medium, and an isogenic enterochelin synthesis mutant (ΔentF) grows very poorly. The enterochelin mutant grows well in low-iron medium supplemented with enterochelin. At high cell densities the ΔentFmutant can compete equally with the wild type in low-iron medium. At low cell densities the ΔentFmutant cannot compete. Furthermore, the growth rate of the wild type is unaffected by cell density. The wild type grows well in low-iron medium even at very low starting densities. Our experiments support a model where at least some enterochelin remains associated with the cells that produce it, and the cell-associated enterochelin enables iron acquisition even at very low cell density. Enterochelin that is not retained by producing cells at low density is lost to dilution. At high cell densities, cell-free enterochelin can accumulate and be shared by all cells in the group. Partial privatization is a solution to the problem of iron acquisition in low-iron, low-cell-density habitats. Cell-free enterochelin allows for iron scavenging at a distance at higher population densities. Our findings shed light on the conditions under which freeloaders might benefit from enterochelin uptake systems.IMPORTANCESociality in microbes has become a topic of great interest. One facet of sociality is the sharing of secreted products, such as the iron-scavenging siderophores. We present evidence that theEscherichia colisiderophore enterochelin is relatively inexpensive to produce and is partially privatized such that it can be efficiently shared only at high producer cell densities. At low cell densities, cell-free enterochelin is scarce and only enterochelin producers are able to grow in low-iron medium. Because freely shared products can be exploited by freeloaders, this partial privatization may help explain how enterochelin production is stabilized inE. coliand may provide insight into when enterochelin is available for freeloaders.

Formation of recombinant proteins in Escherichia coli under control of a nitrogen regulated promoter at low and high cell densities

1996 ◽  
Vol 49 (1-3) ◽  
pp. 45-58 ◽  
Author(s):  
V. Schroeckh ◽  
M. Kujau ◽  
U. Knüpfer ◽  
R. Wenderoth ◽  
J. Mörbe ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Recombinant Proteins ◽  
High Cell ◽  
Cell Densities

Cultivation of Escherichia coli to high cell densities in a dialysis reactor

1993 ◽  
Vol 39 (1) ◽  
pp. 48-52 ◽  
Author(s):  
H. Märkl ◽  
C. Zenneck ◽  
A. Ch. Dubach ◽  
James C. Ogbonna
Keyword(s):  
Escherichia Coli ◽  
High Cell ◽  
Cell Densities ◽  
Dialysis Reactor

scholarly journals Chemotactic behaviour of Escherichia coli at high cell density

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Remy Colin ◽  
Knut Drescher ◽  
Victor Sourjik
Keyword(s):  
Escherichia Coli ◽  
Cell Density ◽  
Collective Motion ◽  
High Cell Density ◽  
Environmental Gradients ◽  
Model Organism ◽  
High Density ◽  
Intermediate Cell ◽  
High Cell ◽  
Cell Densities

AbstractAt high cell density, swimming bacteria exhibit collective motility patterns, self-organized through physical interactions of a however still debated nature. Although high-density behaviours are frequent in natural situations, it remained unknown how collective motion affects chemotaxis, the main physiological function of motility, which enables bacteria to follow environmental gradients in their habitats. Here, we systematically investigate this question in the model organism Escherichia coli, varying cell density, cell length, and suspension confinement. The characteristics of the collective motion indicate that hydrodynamic interactions between swimmers made the primary contribution to its emergence. We observe that the chemotactic drift is moderately enhanced at intermediate cell densities, peaks, and is then strongly suppressed at higher densities. Numerical simulations reveal that this suppression occurs because the collective motion disturbs the choreography necessary for chemotactic sensing. We suggest that this physical hindrance imposes a fundamental constraint on high-density behaviours of motile bacteria, including swarming and the formation of multicellular aggregates and biofilms.

Tracking an Escherichia coli O157:H7–Contaminated Batch of Leafy Greens through a Pilot-Scale Fresh-Cut Processing Line

2014 ◽  
Vol 77 (9) ◽  
pp. 1487-1494 ◽  
Author(s):  
ANNEMARIE L. BUCHHOLZ ◽  
GORDON R. DAVIDSON ◽  
BRADLEY P. MARKS ◽  
EWEN C. D. TODD ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Fluorescent Protein ◽  
Pilot Scale ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Leafy Greens ◽  
Iceberg Lettuce ◽  
Processing Line ◽  
Fresh Cut

Cross-contamination of fresh-cut leafy greens with residual Escherichia coli O157:H7–contaminated product during commercial processing was likely a contributing factor in several recent multistate outbreaks. Consequently, radicchio was used as a visual marker to track the spread of the contaminated product to iceberg lettuce in a pilot-scale processing line that included a commercial shredder, step conveyor, flume tank, shaker table, and centrifugal dryer. Uninoculated iceberg lettuce (45 kg) was processed, followed by 9.1 kg of radicchio (dip inoculated to contain a four-strain, green fluorescent protein–labeled nontoxigenic E. coli O157:H7 cocktail at 106 CFU/g) and 907 kg (2,000 lb) of uninoculated iceberg lettuce. After collecting the lettuce and radicchio in about 40 bags (~22.7 kg per bag) along with water and equipment surface samples, all visible shreds of radicchio were retrieved from the bags of shredded product, the equipment, and the floor. E. coli O157:H7 populations were quantified in the lettuce, water, and equipment samples by direct plating with or without prior membrane filtration on Trypticase soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Based on triplicate experiments, the weight of radicchio in the shredded lettuce averaged 614.9 g (93.6%), 6.9 g (1.3%), 5.0 g (0.8%), and 2.8 g (0.5%) for bags 1 to 10, 11 to 20, 21 to 30, and 31 to 40, respectively, with mean E. coli O157:H7 populations of 1.7, 1.2, 1.1, and 1.1 log CFU/g in radicchio-free lettuce. After processing, more radicchio remained on the conveyor (9.8 g; P < 0.05), compared with the shredder (8.3 g), flume tank (3.5 g), and shaker table (0.1 g), with similar E. coli O157:H7 populations (P > 0.05) recovered from all equipment surfaces after processing. These findings clearly demonstrate both the potential for the continuous spread of contaminated lettuce to multiple batches of product during processing and the need for improved equipment designs that minimize the buildup of residual product during processing.

Metabolism of hybridoma cells and antibody secretion at high cell densities in dialysis tubing

1991 ◽  
Vol 13 (11) ◽  
pp. 873-881 ◽  
Author(s):  
Claudia Käsehagen ◽  
Fritjof Linz ◽  
Gerlinde Kretzmer ◽  
Thomas Scheper ◽  
Karl Schügerl
Keyword(s):  
Hybridoma Cells ◽  
High Cell ◽  
Dialysis Tubing ◽  
Cell Densities ◽  
Antibody Secretion

scholarly journals Pilot-Scale Production of Fatty Acid Ethyl Esters by an Engineered Escherichia coli Strain Harboring the p(Microdiesel) Plasmid

2010 ◽  
Vol 76 (13) ◽  
pp. 4560-4565 ◽  
Author(s):  
Yasser Elbahloul ◽  
Alexander Steinbüchel
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Carbon Sources ◽  
Dry Mass ◽  
Pilot Scale ◽  
Coli Strain ◽  
Fatty Acid Ethyl Esters ◽  
Ethyl Esters ◽  
Scale Production ◽  
A Cell

ABSTRACT Fatty acid ethyl esters (FAEEs) were produced in this study by the use of an engineered Escherichia coli p(Microdiesel) strain. Four fed-batch pilot scale cultivations were carried out by first using glycerol as sole carbon source for biomass production before glucose and oleic acid were added as carbon sources. Cultivations yielded a cell density of up to 61 ± 3.1 g of cell dry mass (CDM) per liter and a maximal FAEE content of 25.4% ± 1.1% (wt/wt) of CDM.

scholarly journals Regulation of Plant Mineral Nutrition by Signal Molecules

2021 ◽  
Vol 9 (4) ◽  
pp. 774
Author(s):  
Vipin Chandra Kalia ◽  
Chunjie Gong ◽  
Sanjay K. S. Patel ◽  
Jung-Kul Lee
Keyword(s):  
Signal Molecules ◽  
Gram Negative Bacteria ◽  
Human Beings ◽  
High Cell ◽  
Specific Chemical ◽  
Gram Negative ◽  
Plant Mineral Nutrition ◽  
Recent Developments ◽  
Cell Densities ◽  
Metabolic Activities

Microbes operate their metabolic activities at a unicellular level. However, it has been revealed that a few metabolic activities only prove beneficial to microbes if operated at high cell densities. These cell density-dependent activities termed quorum sensing (QS) operate through specific chemical signals. In Gram-negative bacteria, the most widely reported QS signals are acylhomoserine lactones. In contrast, a novel QS-like system has been elucidated, regulating communication between microbes and plants through strigolactones. These systems regulate bioprocesses, which affect the health of plants, animals, and human beings. This mini-review presents recent developments in the QS and QS-like signal molecules in promoting plant health.

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