scholarly journals External factors limiting the multiplication potential of Tetrahymena

1981 ◽  
Vol 50 (1) ◽  
pp. 407-418
Author(s):  
E. Hofmann ◽  
G. Cleffmann
Keyword(s):  
Cell Density ◽  
Synthetic Medium ◽  
Reference Conditions ◽  
Nitrogen Sources ◽  
Complete Medium ◽  
Multiplication Rate ◽  
Or Groups ◽  
Cell Densities ◽  
Culture Growth ◽  
O2 Supply

By variation of nutritional and other external conditions we have determined the factors that limit the multiplication rate and the culture growth in Tetrahymena thermophila. The enriched synthetic medium of Kidder & Dewey (1951), a culture temperature of 29 degrees C, and aeration by agitation were chosen as reference conditions. The final cell density is increased by and proportional to the amount of the complete set of nutrients. Testing single nutritional factors or groups of them revealed that only nitrogen sources yield higher cell densities. But none of them or any combination is as capable of increasing the cell density as the complete medium. Therefore, the medium has to be considered as well balanced. Ammonia, cell density, O2 supply, and pH have been excluded as factors limiting the capacity for multiplication. There are no known factors promoting or inhibiting culture growth.

scholarly journals PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

1950 ◽  
Vol 34 (2) ◽  
pp. 231-250 ◽  
Author(s):  
Winston H. Price
Keyword(s):  
Aspartic Acid ◽  
Burst Size ◽  
Synthetic Medium ◽  
Growth Curves ◽  
Acid Synthesis ◽  
Virus Protein ◽  
Complete Medium ◽  
Multiplication Rate ◽  
One Step ◽  
Step Growth

1. Four strains of Staphylococcus muscae have been isolated which differ in their growth rates and phage syntheses in Fildes' synthetic medium. 2. Two of the strains when singly infected cannot release phage in Fildes' synthetic medium unless a substance present in certain acid-hydrolyzed proteins is added to the medium. One of these strains also requires other substance(s) present in acid-hydrolyzed proteins in order to grow in Fildes' medium. 3. The two strains which do not require the addition of the phage-stimulating factor have been found either to synthesize this substance, or one similar to it. One of these strains will not grow in Fildes' medium unless substance(s) present in acid-hydrolyzed proteins is added to the medium. 4. The purified acid-hydrolyzed protein factor necessary for virus liberation does not affect the multiplication rate of uninfected S. muscae cells in Fildes' synthetic medium. 5. The substance is not needed for the adsorption or the invasion of the host cell by the virus. In the absence of the factor, the virus is adsorbed to the cell and "kills" it. 6. An analysis carried out by means of the one-step growth curve technique has indicated that the substance is not concerned simply with the mechanism of virus release, but is necessary for some initial stage in virus synthesis. 7. With one bacterial strain not requiring the AHPF, aspartic acid had to be present at least during the minimum latent period for the cell to form virus. 8. In the absence of aspartic acid, the virus was adsorbed to the cell and killed it, but no virus was released from singly infected bacteria. 9. If the cells were grown in a medium containing aspartic acid and then resuspended in the medium minus aspartic acid, no virus was released, although such cells contained at least two times the amount of aspartic acid necessary for the burst size in the complete medium. 10. Aspartic acid, a constituent of the virus particle, appears from an analysis of one-step growth curves to take part in the initial phase of phage synthesis. 11. The effect of amino acids on virus formation is discussed in relation to the time sequence of virus protein and desoxyribonucleic acid synthesis.

scholarly journals Formulation of a semi-defined medium for high cell density cultivation of Escherichia coli in shake flasks

2016 ◽  
Author(s):  
Wenfa Ng ◽  
Yen-Peng Ting
Keyword(s):  
Cell Density ◽  
Yeast Extract ◽  
High Cell Density ◽  
Nitrogen Sources ◽  
Buffer System ◽  
High Cell ◽  
Carbon And Nitrogen Sources ◽  
E Coli ◽  
Carbon And Nitrogen ◽  
Shake Flasks

Microbes for environmental research should be cultured in growth media with characteristics (e.g., pH, ionic strength, and organic and ionic composition) as close to their original habitat as possible. Additionally, the medium should also enable high cell density to be obtained - needed for providing sufficient cells in subsequent experiments. This in-progress report describes the formulation of a medium with an environmentally-relevant composition (lack of complex organics), and that allows aerobic high cell density cultivation of Escherichia coli DH5α in shake flasks. The formulated medium comprises four components: a buffer system (K2HPO4: 12.54 g/L and KH2PO4: 2.31 g/L), vitamins (yeast extract: 12.0 g/L), salts (NaCl: 5.0 g/L and MgSO4: 0.24 g/L), and carbon and nitrogen sources (D-Glucose: 6.0 g/L and NH4Cl: 1.5 g/L). Notable characteristics of this medium were: high capacity phosphate buffer system (89 mM phosphate); 1:1 molar ratio between D-Glucose and NH4Cl; and yeast extract providing trace elements and a secondary carbon and nitrogen source. Growth experiments revealed that an OD600nm of 9 was attained after 24 hours of cultivation at 37 oC. Glucose and NH4Cl serve as primary carbon and nitrogen sources for this phase of growth. After 48 hours, the OD600nm reached 11, where carbohydrates, lipids and proteins in yeast extract provided the nutrients for biomass formation. Broth’s pH varied between 5.5 and 7.8 during cultivation, which was in the range conducive for E. coli growth. In comparison, the OD600nm of E. coli reached 1.4, 3.2, and 9.2 in three commonly used complex media; Nutrient Broth, LB Lennox, and Tryptic Soy Broth, respectively, over 48 hours under identical culture conditions. In addition, the formulated medium was able to maintain a large viable cell population for a longer period of time (three days) compared to Tryptic Soy Broth. Thus, preliminary data suggested that the formulated medium holds potential for use as a high cell density aerobic growth medium for Gram-negative bacteria.

scholarly journals Effect of Cell Density on the Removal of Microcystis by Coagulation

2020 ◽  
Vol 42 (6) ◽  
pp. 319-326
Author(s):  
Joo Eun Han ◽  
Wontae Lee
Keyword(s):  
Surface Water ◽  
Chlorophyll A ◽  
Cell Density ◽  
Target Cell ◽  
Removal Rate ◽  
Nakdong River ◽  
Removal Rates ◽  
Cell Densities

Objectives:This study evaluated the removal of <i>Microcystis</i> by coagulation in raw waters with three different cell densities.Methods:Raw waters were prepared at three different cell densities (target cell densities of 10,000, 100,000, and 1,000,000 cell/mL; actual cell densities of 9,950, 102,000, and 991,000 cell/mL) by adding <i>Microcystis</i> into surface water from Nakdong river. Jar-tests were conducted with PACL, alum, illite, and loess at dosages of 0-150 mg/L.Results and Discussion:Regardless of coagulant types, the removal rates of <i>Microcystis</i> increased as the coagulant dosages increased. PACl and alum exhibited higher removal rates than illite and loess; PACl was the best coagulant to remove <i>Microcystis</i>. Removal of chlorophyll-a was highest when PACl added at 20.4 mg/L, and no significant increase in removal rate was observed with higher dosages of PACl. However, removal rates of chlorophyll-a by illite and loess gradually increased as the dosages increased.Conclusions:With the coagulants tested in this study, removal rates of <i>Microcystis</i> increased as the coagulant dosages increased. Removal rates of <i>Microcystis</i> increased as the cell densities increased probably because <i>Microcystis</i> acted as particles which could enhance the coagulation efficiency.

scholarly journals Cell density-dependent stimulation of PAI-1 and hyaluronan synthesis by TGF-β in orbital fibroblasts

2016 ◽  
Vol 229 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Erika Galgoczi ◽  
Florence Jeney ◽  
Annamaria Gazdag ◽  
Annamaria Erdei ◽  
Monika Katko ◽  
...  
Keyword(s):  
Cell Density ◽  
Inverse Correlation ◽  
Fold Increase ◽  
Dermal Fibroblasts ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Density Dependent ◽  
Cell Densities ◽  
Orbital Fibroblasts ◽  
Pai 1

During the course of Graves’ orbitopathy (GO), orbital fibroblasts are exposed to factors that lead to proliferation and extracellular matrix (ECM) overproduction. Increased levels of tissue plasminogen activator inhibitor type 1 (PAI-1 (SERPINE1)) might promote the accumulation of ECM components. PAI-1 expression is regulated by cell density and various cytokines and growth factors including transforming growth factorβ(TGF-β). We examined the effects of increasing cell densities and TGF-β on orbital fibroblasts obtained from GO patients and controls. Responses were evaluated by the measurement of proliferation, PAI-1 expression, and ECM production. There was an inverse correlation between cell density and the per cell production of PAI-1. GO orbital, normal orbital, and dermal fibroblasts behaved similarly in this respect. Proliferation rate also declined with increasing cell densities. Hyaluronan (HA) production was constant throughout the cell densities tested in all cell lines. In both GO and normal orbital fibroblasts, but not in dermal fibroblasts, TGF-β stimulated PAI-1 production in a cell density-dependent manner, reaching up to a five-fold increase above baseline. This has been accompanied by increased HA secretion and pericellular HA levels at high cell densities. Increasing cell density is a negative regulator of proliferation and PAI-1 secretion both in normal and GO orbital fibroblasts; these negative regulatory effects are partially reversed in the presence of TGF-β. Cell density-dependent regulation of PAI-1 expression in the orbit, together with the local cytokine environment, may have a regulatory role in the turnover of the orbital ECM and may contribute to the expansion of orbital soft tissue in GO.

Effects of explant position and orientation, medium ph and nitrogen sources on micropropagation of blackberry

2021 ◽  
Vol 12 (4) ◽  
pp. 84-92
Author(s):  
Thábata Cristina Faxina de Aguiar ◽  
Ana Paola Negri ◽  
Pedro Boff ◽  
Murilo Dalla Costa ◽  
Mari Inês Carissimi Boff ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Nitrogen Sources ◽  
Original Position ◽  
Multiplication Rate ◽  
Highest Weight ◽  
Explant Position ◽  
Rubus Species ◽  
Position And Orientation ◽  
Ph Level

Composition of the medium and the explant origin are factors that interfere on success of micropropagation of Rubus species. For blackberry cultivar LochNess it was not investigated yet how the position and orientation of explant, pH levels and nitrogen source interfere on micropropagation. In this work, focused on the establishment of in vitro culture, variables were studied on R. fruticosus cv Loch Ness, such as the choice of the explants depending on their original position on the mother plant, pH level and nitrogen sources of the culture medium. For the first time in vitro on Rubus, the downward orientation (capogatto) of shoot tips explants was compared with the normal upward orientation. The highest weight and length values were recorded for the shoots proliferated from basal and nodal explants. For the initiation medium, the best multiplication rate were obtained in pH adjusted to 4.5. Shoot length was influenced by the nitrogen source; when associated with an increased light intensity, the complete substitution of ammonium by nitrate allowed results comparable with those obtained with the control medium containing both sources. The use of aminoacids did not improve the results. Apex orientation did not affect anatomical parameters or rooting rates of wild Rubus, but more efforts should be devoted on in vitro capogatto technique considering that advantages like reduction of plant growth regulators, cultivation on the same medium culture for more time and easily rooting can be established.

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 Use of wheat straw and chicken feather hydrolysates as a complete medium for lactic acid production

2018 ◽  
Vol 36 (No. 2) ◽  
pp. 146-153 ◽  
Author(s):  
Gharwalová Lucia ◽  
Paulová Leona ◽  
Patáková Petra ◽  
Branská Barbora ◽  
Melzoch Karel
Keyword(s):  
Lactic Acid ◽  
Wheat Straw ◽  
Acid Production ◽  
Low Cost ◽  
Lactic Acid Production ◽  
Nitrogen Sources ◽  
Batch Process ◽  
Complete Medium ◽  
Biotechnological Production ◽  
Acid Yield

Biotechnological production of lactic acid has experienced a boom that is hindered only by the lack of low-cost, abundant material that might be used as a substrate for lactic acid bacteria. Such material should contain not only carbon but also complex nitrogen sources, amino acids and vitamins necessary for the balanced growth of the bacteria. Here, for the first time, a combination of hydrolysates of wheat straw and chicken feathers was used as a complete waste cultivation medium for lactic acid production. It was shown to be a promising substrate for lactic acid production, reducing the medium price by 73% compared with MRS broth, providing more than 98% lactic acid yield and high productivity (2.28 ± 0.68 g/l/h) in a fed-batch process using Lactobacillus reuterii LHR14.

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.

Reduction of Selenite and Detoxification of Elemental Selenium by the Phototrophic BacteriumRhodospirillum rubrum

1999 ◽  
Vol 65 (11) ◽  
pp. 4734-4740 ◽  
Author(s):  
J. Kessi ◽  
M. Ramuz ◽  
E. Wehrli ◽  
M. Spycher ◽  
R. Bachofen
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Density ◽  
Culture Medium ◽  
Rhodospirillum Rubrum ◽  
Buoyant Density ◽  
Elemental Selenium ◽  
Selenite Reduction ◽  
Final Cell Density ◽  
Cell Densities

ABSTRACT The effect of selenite on growth kinetics, the ability of cultures to reduce selenite, and the mechanism of detoxification of selenium were investigated by using Rhodospirillum rubrum. Anoxic photosynthetic cultures were able to completely reduce as much as 1.5 mM selenite, whereas in aerobic cultures a 0.5 mM selenite concentration was only reduced to about 0.375 mM. The presence of selenite in the culture medium strongly affected cell division. In the presence of a selenite concentration of 1.5 mM cultures reached final cell densities that were only about 15% of the control final cell density. The cell density remained nearly constant during the stationary phase for all of the selenite concentrations tested, showing that the cells were not severely damaged by the presence of selenite or elemental selenium. Particles containing elemental selenium were observed in the cytoplasm, which led to an increase in the buoyant density of the cells. Interestingly, the change in the buoyant density was reversed after selenite reduction was complete; the buoyant density of the cells returned to the buoyant density of the control cells. This demonstrated that R. rubrum expels elemental selenium across the plasma membrane and the cell wall. Accordingly, electron-dense particles were more numerous in the cells during the reduction phase than after the reduction phase.

scholarly journals Effects of Encapsulated Cells on the Physical–Mechanical Properties and Microstructure of Gelatin Methacrylate Hydrogels

2019 ◽  
Vol 20 (20) ◽  
pp. 5061 ◽  
Author(s):  
Srikumar Krishnamoorthy ◽  
Behnam Noorani ◽  
Changxue Xu
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Viability ◽  
Physical Properties ◽  
Pore Size ◽  
Cell Density ◽  
Tensile Modulus ◽  
Encapsulated Cells ◽  
3T3 Fibroblasts ◽  
Cell Densities

Gelatin methacrylate (GelMA) has been gaining popularity in recent years as a photo-crosslinkable biomaterial widely used in a variety of bioprinting and tissue engineering applications. Several studies have established the effects of process-based and material-based parameters on the physical–mechanical properties and microstructure of GelMA hydrogels. However, the effect of encapsulated cells on the physical–mechanical properties and microstructure of GelMA hydrogels has not been fully understood. In this study, 3T3 fibroblasts were encapsulated at different cell densities within the GelMA hydrogels and incubated over 96 h. The effects of encapsulated cells were investigated in terms of mechanical properties (tensile modulus and strength), physical properties (swelling and degradation), and microstructure (pore size). Cell viability was also evaluated to confirm that most cells were alive during the incubation. It was found that with an increase in cell density, the mechanical properties decreased, while the degradation and the pore size increased.

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