scholarly journals Production of prodigiosin pigment by Serratia marcescens is negatively associated with cellular ATP levels during high-rate, low-cell-density growth

2020 ◽  
Vol 66 (3) ◽  
pp. 243-255 ◽  
Author(s):  
Pryce L. Haddix ◽  
Robert M.Q. Shanks
Keyword(s):  
Growth Rate ◽  
Serratia Marcescens ◽  
Cell Density ◽  
Chemostat Culture ◽  
High Rate ◽  
Phase Cell ◽  
Intact Cells ◽  
Atp Levels ◽  
Density Growth ◽  
Low Cell Density

Serratia marcescens is a facultatively anaerobic bacterium and the most recognized producer of the hydrophobic pigment prodigiosin. Previous work has shown that prodigiosin both increases ATP production during population lag phase and approximately doubles the stationary-phase cell yield. Here, we employed both batch and chemostat culture methods to investigate prodigiosin’s role during high rate growth at low cell density as peak cellular ATP levels decline. Batch culture experiments utilizing artificial pigment induction showed an ATP reduction during low cell density growth. In addition, pigment induction during fixed growth rate chemostat culture revealed a negative correlation between cellular levels of prodigiosin and ATP (r = −0.95). Variable growth rate chemostat experiments showed an inverse relationship between ATP per cell and prodigiosin per cell during low-density growth but a direct relationship during high-density growth. Rate modeling of chemostat data quantified the pigment’s effect on cellular levels of ATP for both population growth phases. Finally, prodigiosin production in a heterologous bacterium led to ATP decline. These data with intact cells complement the established in vitro proton import function of prodigiosin pigment and may indicate an energy-spilling function during high rate, low cell density growth.

Associations Between Cellular Levels of ATP and Prodigiosin Pigment Throughout the Growth Cycle of Serratia marcescens

2021 ◽  
Author(s):  
Pryce L. Haddix
Keyword(s):  
Stationary Phase ◽  
Serratia Marcescens ◽  
Stationary Phases ◽  
Growth Cycle ◽  
High Density ◽  
High Rate ◽  
Lag Phase ◽  
Positive Role ◽  
Atp Production ◽  
Density Growth

ABSTRACT Serratia marcescens is a prolific producer of the red, membrane-associated pigment prodigiosin. Earlier work has established both a positive role for prodigiosin in ATP production during population lag phase and a negative role during high-rate, low cell density growth. This study uses the growth rate and growth phase modulation afforded by chemostat culture to extend prodigiosin functional analysis to the high density and stationary phases. Cellular levels of prodigiosin were positively associated with cellular levels of ATP during high-density growth, and artificial pigment induction during this phase increased cellular ATP. Following peak high density ATP per cell, early stationary phase enabled significant population growth while prodigiosin levels remained high and ATP declined. During late stationary phase, ATP per cell was positively associated with prodigiosin per cell while both declined during continued growth. These results provide correlational evidence for multiple effects of prodigiosin pigment on ATP production throughout the growth cycle. Earlier work and the data presented here enable formulation of a working model for the oscillating relationships between cellular levels of ATP and prodigiosin during batch culture.

Effect of growth rate on the eicosapentaenoic acid and docosahexaenoic acid content of Isochrysis galbana in chemostat culture

1994 ◽  
Vol 41 (1) ◽  
pp. 23-27 ◽  
Author(s):  
E. Molina Grima ◽  
J. A. S�nchez P�rez ◽  
F. Garc�a Camacho ◽  
J. M. Fern�ndez Sevilla ◽  
F. G. Aci�n Fern�ndez
Keyword(s):  
Growth Rate ◽  
Docosahexaenoic Acid ◽  
Eicosapentaenoic Acid ◽  
Acid Content ◽  
Chemostat Culture ◽  
Isochrysis Galbana

Bioprocess optimisation for high cell density endoinulinase production from recombinant Aspergillus niger

2021 ◽  
Author(s):  
Pfariso Maumela ◽  
Shaunita Rose ◽  
Eugene van Rensburg ◽  
Annie Chimphango ◽  
Johann Gorgens
Keyword(s):  
Growth Rate ◽  
Aspergillus Niger ◽  
Cell Density ◽  
Enzyme Production ◽  
High Cell Density ◽  
Nitrogen Concentration ◽  
High Cell ◽  
Feed Concentration ◽  
Volumetric Activity ◽  
Activity Increase

Abstract Endoinulinases gene was expressed in recombinant Aspergillus niger for selective and high-level expression using an exponential fed-batch fermentation. The effects of the growth rate (µ), glucose feed concentration, nitrogen concentration and fungal morphology, on enzyme production were evaluated. A recombinant endoinulinases with a molecular weight of 66 KDa was secreted. Endoinulinases production was growth associated at µ> 0.04 h -1 , which is characteristic of the constitutive gpd promoter used for the enzyme production. The highest volumetric activity (670 U/ml) was achieved at a growth rate of 93% of µ max (0.07 h -1 ), while enzyme activity (506 U/ml) and biomass substrate yield (0.043 g biomassDW /g glucose ) significantly decreased at low µ (0.04 h -1 ). Increasing the feed concentration resulted in high biomass concentrations and viscosity, which necessitated high agitation for improved mixing and oxygen. However, the high agitation and low DO levels (ca. 8% of saturation) led to pellet disruption and growth in mycelial morphology. Enzyme production profiles, product (Y p/s ) and biomass (Y x/s ) yield coefficients were not affected by feed concentration and morphological change. The gradual increase in the concentration of nitrogen sources showed that, a nitrogen limited culture was not suitable for endoinulinases production in recombinant A. niger. Moreover, the increase in enzyme volumetric activity was still directly related to an increase in biomass concentration. An increase in nitrogen concentration, from 3.8 to 12 g/L, resulted in volumetric activity increase from 393 to 670 U/ml, but the Y p/s (10053 U/g glucose ) and Y x/s (0.049 g biomasDWs /g glucose ) did not significantly change. The data demonstrated the potential of recombinant A. niger and high cell density fermentation for the development of largescale endoinulinases production system.

Growth-dependent regulation of system A in SV40-transformed fetal rat hepatocytes

1988 ◽  
Vol 255 (3) ◽  
pp. C261-C270 ◽  
Author(s):  
M. E. Handlogten ◽  
M. S. Kilberg
Keyword(s):  
Cell Density ◽  
De Novo ◽  
Membrane Vesicles ◽  
Rat Hepatocytes ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Plasma Membrane Vesicles ◽  
Intact Cells ◽  
System A

Fetal RLA209-15 hepatocytes, transformed with a temperature-sensitive SV40 mutant, behave like fully differentiated cells at the growth-restrictive temperature of 40 degrees C. Conversely, incubation at the growth-permissive temperature of 33 degrees C results in a transformed phenotype characterized by rapid cell division and decreased production of liver-specific proteins. The results presented here demonstrate that the cells at 33 degrees C exhibited high rates of system A transport, but transfer to 40 degrees C reduced the activity greater than 50% within 24 h. This decline in transport was independent of cell density, although the basal rate of uptake was inversely proportional to cell density in rapidly dividing cells. Transfer of cells from 40 to 33 degrees C resulted in an enhancement of system A activity that was blocked by tunicamycin. Plasma membrane vesicles from cells maintained at either 33 or 40 degrees C retained uptake rates proportional to those in the intact cells; this difference in transport activity could also be demonstrated after detergent solubilization and reconstitution. Collectively, these data indicate that de novo synthesis of the system A carrier is regulated in conjunction with temperature-dependent cell growth in RLA209-15 hepatocytes.

scholarly journals Inhibition of Apoptosis in a Human Pre-B–Cell Line by CD23 Is Mediated Via a Novel Receptor

Blood ◽  
1997 ◽  
Vol 90 (1) ◽  
pp. 234-243 ◽  
Author(s):  
Lindsey J. White ◽  
Bradford W. Ozanne ◽  
Pierre Graber ◽  
Jean-Pierre Aubry ◽  
Jean-Yves Bonnefoy ◽  
...  
Keyword(s):  
Cell Line ◽  
Cell Density ◽  
Flow Cytometric Analysis ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cell Line ◽  
Cell Densities ◽  
Lymphocytic Leukemia Cell ◽  
Low Cell Density ◽  
Cells Cultured

Abstract Human CD23 is a 45-kD type II membrane glycoprotein, which functions as a low-affinity receptor for IgE and as a ligand for the CD21 and CD11b/CD11c differentiation antigens. CD23 is released from the surface of cells as soluble fragments, and a 25-kD species of soluble CD23 (sCD23) appears to act as a multifunctional cytokine. In this report, sCD23 is shown to sustain the growth of low cell density cultures of a human pre-B–acute lymphocytic leukemia cell line, SMS-SB: no other cytokine tested was able to induce this effect. Flow cytometric analysis indicates that sCD23 acts to prevent apoptosis of SMS-SB cells. SMS-SB cells cultured at low cell density possess low levels of bcl-2 protein. Addition of sCD23 to cells at low cell density maintained bcl-2 expression at levels equivalent to those observed in SMS-SB cells cultured at higher cell densities. No CD23 mRNA was found in SMS-SB cells, ruling out an autocrine function for CD23 in this cell line model. Although SMS-SB cells do not express the known receptors for CD23, namely CD21, CD11b-CD18, or CD11c-CD18, the cells specifically bind CD23-containing liposomes, but not glycophorin-containing liposomes. Binding of CD23-containing liposomes is inhibited by anti-CD23 but not by anti-CD21 or anti-CD11b/c monoclonal antibodies. The data show that sCD23 prevents apoptosis of the SMS-SB cell line by acting through a novel receptor.

scholarly journals Hyaluronate synthetase inhibition by normal and transformed human fibroblasts during growth reduction

1987 ◽  
Vol 104 (4) ◽  
pp. 1105-1115 ◽  
Author(s):  
K Matuoka ◽  
M Namba ◽  
Y Mitsui
Keyword(s):  
Cell Proliferation ◽  
Cell Density ◽  
Human Fibroblasts ◽  
Transformed Cells ◽  
Synthetase Activity ◽  
Intact Cells ◽  
Free System ◽  
Glycosaminoglycan Synthesis ◽  
Cell Free System ◽  
A Cell

To establish the relation of glycosaminoglycan synthesis to cell proliferation, we investigated the synthesis of individual glycosaminoglycan species by intact cells and in a cell-free system, using normal and transformed human fibroblasts under differing culture conditions. Reducing serum concentration brought about a marked decline in the synthesis of hyaluronate (HA) as well as cell proliferation on both normal and transformed cells. Both HA synthesis and proliferation decreased with increasing cell densities markedly (in inverse proportion to cell density) in normal cells but gradually in transformed cells. This noticeable congruity of the changes in HA synthesis and proliferation indicates that the change in HA synthesis is related primarily to cell proliferation rather than to cell density or cellular transformation. Examination of HA synthesis in a cell-free system demonstrated that the activity of HA synthetase also fluctuated in conjunction with cell proliferation. Furthermore, growth-reduced cells (except crowded transformed cells) inhibited cell-free HA synthesis and this inhibition was induced coincidentally with a decrease in both HA synthetase activity and proliferation. These findings suggest that the change in HA synthesis is significant in the regulation of cell proliferation.

Density-Dependent Growth Adaptation Kinetics in 3T 3 Cell Populations Following Sudden [Ca2+] and Temperature Changes. A Comparison with SV40-3T3 Cells

1979 ◽  
Vol 34 (3-4) ◽  
pp. 279-283 ◽  
Author(s):  
Jürgen van der Bosch ◽  
Ilse Sommer ◽  
Heinz Maier ◽  
Willy Rahmig
Keyword(s):  
Growth Rate ◽  
Cell Density ◽  
Cell Number ◽  
Cell Populations ◽  
3T3 Cells ◽  
Density Dependent ◽  
Cell Densities ◽  
Dependent Growth ◽  
Growth Adaptation ◽  
Stationary Cell

Abstract Lowered extracellular [Ca2+] causes low growth rates and low stationary cell densities in 3T3 cell cultures as compared to physiological [Ca2+]. Under otherwise constant conditions the extra­ cellular [Ca2+] determines a stable stationary cell density, which can be readied by increase of net cell number or decrease of net cell number, depending on cell density at the time of [Ca2+] adjustment. SV40-3T3 cells do not show this [Ca2+] dependency. At 39 °C 3T3 and SV40-3T3 cell populations show an increased growth rate at low cell densities as compared to cell populations at 35 °C. Approaching the stationary density the growth rate of both cell sorts is reduced faster at 39 °C than at 35 °C, leading to lower stationary cell densities at 39 °C than at 35 °C. A temperature change from 39 °C to 35 °C or in the opposite direction can affect the stationary cell density of 3T3 cell populations only if applied before reduction of growth rate by density-dependent growth-inhibiting principles has taken place.

scholarly journals Quorum Sensing Controls Biofilm Formation in Vibrio cholerae through Modulation of Cyclic Di-GMP Levels and Repression of vpsT

2008 ◽  
Vol 190 (7) ◽  
pp. 2527-2536 ◽  
Author(s):  
Christopher M. Waters ◽  
Wenyun Lu ◽  
Joshua D. Rabinowitz ◽  
Bonnie L. Bassler
Keyword(s):  
Quorum Sensing ◽  
Vibrio Cholerae ◽  
Cell Density ◽  
Biofilm Formation ◽  
High Cell Density ◽  
High Cell ◽  
Chemical Signaling ◽  
Signaling Systems ◽  
Genes Encoding ◽  
Low Cell Density

ABSTRACT Two chemical signaling systems, quorum sensing (QS) and 3′,5′-cyclic diguanylic acid (c-di-GMP), reciprocally control biofilm formation in Vibrio cholerae. QS is the process by which bacteria communicate via the secretion and detection of autoinducers, and in V. cholerae, QS represses biofilm formation. c-di-GMP is an intracellular second messenger that contains information regarding local environmental conditions, and in V. cholerae, c-di-GMP activates biofilm formation. Here we show that HapR, a major regulator of QS, represses biofilm formation in V. cholerae through two distinct mechanisms. HapR controls the transcription of 14 genes encoding a group of proteins that synthesize and degrade c-di-GMP. The net effect of this transcriptional program is a reduction in cellular c-di-GMP levels at high cell density and, consequently, a decrease in biofilm formation. Increasing the c-di-GMP concentration at high cell density to the level present in the low-cell-density QS state restores biofilm formation, showing that c-di-GMP is epistatic to QS in the control of biofilm formation in V. cholerae. In addition, HapR binds to and directly represses the expression of the biofilm transcriptional activator, vpsT. Together, our results suggest that V. cholerae integrates information about the vicinal bacterial community contained in extracellular QS autoinducers with the intracellular environmental information encoded in c-di-GMP to control biofilm formation.

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