Magnesium Starved Cells of Euglena gracilis - a Possible Model System for Studying Mg2+ Influx?

1996 ◽  
Vol 51 (3-4) ◽  
pp. 165-173
Author(s):  
Gabriele Scholten-Beck
Keyword(s):  
Euglena Gracilis ◽  
Culture Medium ◽  
Binding Assay ◽  
Lectin Binding ◽  
Model Organism ◽  
Culture Conditions ◽  
Free Medium ◽  
Drastic Reduction ◽  
Surface Carbohydrates ◽  
Oval Shape

Abstract In order to obtain a model which allows to directly study Mg2+ influx into the cell, Mg2+ deficiency was induced in the unicellular photoautotrophic flagellate Euglena gracilis. Lack of Mg2+ in the culture medium leads to a number of morphological, biochemical, and physio­ logical changes in E uglena gracilis. The rate of cell division was reduced under Mg2+-free conditions. Subsequently an enlargement of the cells was observed and they changed from spindle-like to oval shape. The Mg2+-starved cells were well filled with paramylon granules, while their motility and vitality was not impaired. Concurrently with the larger cell size the protein-, carbohydrate-, and chlorophyll content of the cells increased. Further changes were observed in the surface carbohydrates. The proportion of cells with galactose, N-acetyl-galac-tosamine and mannose on the cell surface rose in the Mg2+-starved cultures, shown in a lectin-binding assay. Fucose was found on the pellicle of Mg2+-starved cells only. Cultivation of E uglena gracilis in Mg2+-free medium induced a drastic reduction of the intracellular Mg2+ concentration already after 24 h (from 233 nmol/106 cells to 82 nmol/106 cells). When Mg2+ was made available again, the Mg2+-starved cells took them up rapidly and the intracellular concentration of free Mg2+ rose. As Mg2+ depletion could be induced in Euglena gracilis easily by manipulating the culture conditions and as the cells remained viable, it was con­ cluded that this flagellate can be used as a model organism for studying the Mg2+ uptake of eukaryotic cells.

scholarly journals Isolation and characterization of a motility-defective mutant of Euglena gracilis

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10002
Author(s):  
Shuki Muramatsu ◽  
Kohei Atsuji ◽  
Koji Yamada ◽  
Kazunari Ozasa ◽  
Hideyuki Suzuki ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Euglena Gracilis ◽  
Model Organism ◽  
Cost Effective ◽  
Industrial Applications ◽  
Culture Conditions ◽  
Wild Type ◽  
Mass Cultivation ◽  
Isolation And Characterization ◽  
Defective Mutant

Euglena gracilis is a green photosynthetic microalga that swims using its flagellum. This species has been used as a model organism for over half a century to study its metabolism and the mechanisms of its behavior. The development of mass-cultivation technology has led to E. gracilis application as a feedstock in various products such as foods. Therefore, breeding of E. gracilis has been attempted to improve the productivity of this feedstock for potential industrial applications. For this purpose, a characteristic that preserves the microalgal energy e.g., reduces motility, should be added to the cultivars. The objective of this study was to verify our hypothesis that E. gracilis locomotion-defective mutants are suitable for industrial applications because they save the energy required for locomotion. To test this hypothesis, we screened for E. gracilis mutants from Fe-ion-irradiated cell suspensions and established a mutant strain, ${\mathrm{M}}_{3}^{-}$ZFeL, which shows defects in flagellum formation and locomotion. The mutant strain exhibits a growth rate comparable to that of the wild type when cultured under autotrophic conditions, but had a slightly slower growth under heterotrophic conditions. It also stores 1.6 times the amount of paramylon, a crystal of β-1,3-glucan, under autotrophic culture conditions, and shows a faster sedimentation compared with that of the wild type, because of the deficiency in mobility and probably the high amount of paramylon accumulation. Such characteristics make E. gracilis mutant cells suitable for cost-effective mass cultivation and harvesting.

Lectin Binding Studies on RNA Tumor Virus-Infected Cells

1975 ◽  
Vol 33 ◽  
pp. 326-327
Author(s):  
D. C. Hixson
Keyword(s):  
Binding Sites ◽  
Lectin Binding ◽  
Culture Conditions ◽  
3T3 Cells ◽  
Binding Studies ◽  
Con A ◽  
Microscopic Studies ◽  
Tumor Virus ◽  
Infected Cells ◽  
Cell Culture Conditions

The abilities of plant lectins to preferentially agglutinate malignant cells and to bind to specific monosaccharide or oligosaccharide sequences of glycoproteins and glycolipids make them a new and important biochemical probe for investigating alterations in plasma membrane structure which may result from malignant transformation. Electron and light microscopic studies have demonstrated clustered binding sites on surfaces of SV40-infected or tryp- sinized 3T3 cells when labeled with concanavalin A (con A). No clustering of con A binding sites was observed in normal 3T3 cells. It has been proposed that topological rearrangement of lectin binding sites into clusters enables con A to agglutinate SV40-infected or trypsinized 3T3 cells (1). However, observations by other investigators have not been consistent with this proposal (2) perhaps due to differences in reagents used, cell culture conditions, or labeling techniques. The present work was undertaken to study the lectin binding properties of normal and RNA tumor virus-infected cells and their associated viruses using lectins and ferritin-conjugated lectins of five different specificities.

Study on Optimization of Fermentation Condition for Nitrilase-Producer Escherichia Coli BL21 (DE3)/pET-Nit

2011 ◽  
Vol 175-176 ◽  
pp. 192-196 ◽  
Author(s):  
Li Li Feng ◽  
Jian Fei Zhang ◽  
Hui Luo ◽  
Zheng Li ◽  
Hong Jie Zhang
Keyword(s):  
Escherichia Coli ◽  
Recombinant Strain ◽  
Culture Medium ◽  
Culture Conditions ◽  
Fermentation Condition ◽  
Hydrogen Phosphate ◽  
Strain Bl21 ◽  
Initial Ph ◽  
Potassium Hydrogen ◽  
Optimization Of Fermentation

The paper concentrated on the optimization of the recombinant strain BL21 (DE3)-PE7-Nit. The component of culture medium and the culture conditions were optimized. The optimized medium was: yeast extract 10 g/l, L-glutamate sodium 8 g/l, MgSO4.7H2O 0.7 g/l, Isopropyl-β-D-thiogalactopyranoside 0.3 mmol/L, potassium hydrogen phosphate 0.5 g / L, phosphate Potassium 0.5 g / L and the culture condition was: initial pH 7.0, inoculum 2%. The result showed that the activity of nitrilase prepared with these conditions increased by 130.37 % through optimization.

scholarly journals Sensitive and Selective Culture Medium for Detection of Environmental Clostridium difficile Isolates without Requirement for Anaerobic Culture Conditions

2014 ◽  
Vol 52 (9) ◽  
pp. 3259-3263 ◽  
Author(s):  
Jennifer L. Cadnum ◽  
Kelly N. Hurless ◽  
Abhishek Deshpande ◽  
Michelle M. Nerandzic ◽  
Sirisha Kundrapu ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Culture Medium ◽  
Culture Conditions ◽  
Anaerobic Culture ◽  
Selective Culture Medium

Mechanism of cystine reaccumulation by cystinotic fibroblasts in vitro

1990 ◽  
Vol 10 (2) ◽  
pp. 225-229 ◽  
Author(s):  
Susan Forster ◽  
Lynne Scarlett ◽  
John B. Lloyd
Keyword(s):  
Plasma Membrane ◽  
Culture Medium ◽  
Human Fibroblasts ◽  
Competitive Inhibitor ◽  
Free Medium ◽  
Lysosome Membrane ◽  
Putative Mechanism

It is well established that when cystine-depleted cystinotic cells are cultured in cystine-containing medium, they reaccumulate cystine within their lysosomes more rapidly than when cultured in cystine-free medium. This has been a puzzling result, since the lysosome membrane of cystinotic cells is impermeable to cystine. To probe the mechanism of cystine reaccumulation, we have measured reaccumulation in the presence of colchicine, an inhibitor of pinocytosis, or of glutamate, a competitive inhibitor of cystine transport into human fibroblasts. Colchicine had no effect, thus eliminating pinocytosis as a putative mechanism for cystine translocation from the culture medium to the lysosomes. Glutamate, however, strongly inhibited cystine reaccumulation. It is concluded that the true mechanism is as follows. 1. Exogenous cystine crosses the plasma membrane on the cystine-glutamate porter. 2. Cystine is reduced in the cytoplasm by GSH. 3. The cysteine that is generated enters the lysosome, where it becomes cystine by participating in the reduction of cystine residues during intralysosomal proteolysis, or by autoxidation.

Inhibition of proliferative growth in glioma cells by calmodulin antagonists

1986 ◽  
Vol 65 (1) ◽  
pp. 74-79 ◽  
Author(s):  
Nobuyuki Suzuki ◽  
Tetsuo Kanno ◽  
Yutaka Nagata ◽  
Taiji Kato
Keyword(s):  
Culture Medium ◽  
Deoxyribonucleic Acid ◽  
Control Level ◽  
Glioma Cells ◽  
Culture Conditions ◽  
Calmodulin Antagonists ◽  
High Concentration ◽  
Content Type ◽  
Chemically Induced ◽  
Proliferative Growth

✓ The effects of several calmodulin antagonists, such as N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide hydrochloride (W-7) and its dechlorinated structural analogue (W-5), on the growth and proliferation of cultured and transplanted glioma (GA-1, chemically induced from rat glioblasts) were evaluated. Under culture conditions, the concentration of W-7 necessary to exert 50% inhibition of GA-1 glioma cell growth was 50 µM. However, W-5, with a lower binding affinity to calmodulin than W-7, caused no definite inhibition of the proliferation of GA-1 cells in culture. When a low concentration of W-7 (12.5 µM) was added to the culture medium, deoxyribonucleic acid (DNA) synthesis in the GA-1 glioma cells was not markedly affected, whereas both ribonucleic acid (RNA) and protein syntheses were strongly suppressed on incubation for 24 hours. When a high concentration of W-7 (25.0 to 75.0 µM) was applied to the medium, synthesis of DNA, RNA, and protein was distinctly inhibited. When W-7 (50.0 µM) was added to the incubation medium, the calmodulin concentration in the cultured GA-1 was reduced to as much as half the control level within 2 hours, and thereafter remained at this level. Whereas control rats intraperitoneally transplanted with GA-1 cells could survive for 14 to 21 days, daily intraperitoneal injections of W-7 at concentrations of 1.0, 3.0, and 10.0 mg/kg body weight prolonged the survival span to between 21 and 26 days; this corresponded to an increased life span of about 40% compared to the controls.

scholarly journals Screening of Amazonian bacillus strains for lipase production using glycerol as substrate

ScientiaTec ◽  
2020 ◽  
Vol 7 (03) ◽  
Author(s):  
Giandra Volpato ◽  
Victória Furtado Migliavacca ◽  
Bruna Coelho de Andrade ◽  
Júlio Xandro Heck ◽  
Marco Antônio Záchia Ayub
Keyword(s):  
Organic Synthesis ◽  
Culture Medium ◽  
Lipolytic Activity ◽  
Gum Arabic ◽  
Lipase Production ◽  
Culture Conditions ◽  
Search And Selection ◽  
Triton X ◽  
Potential Use ◽  
Selection Of

The industrial application of lipolytic enzymes has been studied mainly due to the ability of these enzymes in catalyze reactions of synthesis and their stability in various organic solvents. One possibility is the use of lipase the organic synthesis, taking advantage as the generation of waste and difficult recovery of sub bioproducts. In this work, we carried out a selection of eighty-four isolates of Bacillus amazonian for lipase production, of which 30 strains showed lipolytic activity. The study of the culture conditions was performed through a Plackett-Burman experimental design using the strain that presented the highest lipolytic activity in a culture medium using glycerol as substrate.  The studied conditions were: concentration of soybean oil, olive oil, triton X-100, gum arabic, glycerol, and (NH4)2SO4, pH, temperature and concentration of inoculums. The best result obtained were 27 U/L in 48 h of cultivation by Bacillus circulans BL53. This work shows that the search and selection of microorganism with lipolytic activities can facilitate the discovery of new lipases, with potential use as by-product surplus.

Production and control of extracellular enzymes in Micrococcus sodonensis

1974 ◽  
Vol 20 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Cecily Mills ◽  
J. N. Campbell
Keyword(s):  
Alkaline Phosphatase ◽  
Inorganic Phosphate ◽  
Culture Medium ◽  
Extracellular Enzymes ◽  
Synthetic Medium ◽  
Culture Conditions ◽  
The Other ◽  
Organic Nutrients ◽  
And Control ◽  
Logarithmic Growth

Micrococcus sodonensis has been shown to produce several extracellular enzymes: an alkaline phosphatase, at least two forms of phosphodiesterase, a 5′-nucleotidase, and an alkaline proteinase. The quantitative release of these enzymes into the culture medium during logarithmic growth under all the various culture conditions tested indicates that these enzymes are truly extracellular in nature. Inorganic phosphate repressed the production of the alkaline phosphatase in synthetic as well as in complex media, whereas, the repression of the production of active diesterase and 5′-nucleotidase by inorganic phosphate was partly reversed by the addition of supplemental organic nutrients to the culture medium. Proteinase production was independent of the culture conditions used. A mutant strain of M. sodonensis with an altered production of diesterase was obtained; the other extracellular enzymes were unaffected. These results suggest that the extracellular enzymes of M. sodonensis are not produced in a pleiotropic fashion since the level of one of the enzymes can be changed without affecting a corresponding change in the levels of the other enzymes. An extracellular high molecular weight carbohydrate fraction was shown to be produced by M. sodonensis in synthetic medium. The fraction was also shown to contain glycoprotein.

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