Influence Of Growth Medium Composition Research Articles

Effect of growth medium composition on the efficiency of non-ribosomal synthesis in bacteria of the genus Bacillus

Bacteria of the genus Bacillus are known for their ability to suppress a wide range of pathogenic microflora through the production of a variety of secondary metabolites, a significant proportion of which are non-ribosomal peptides. The importance of selecting conditions for the most efficient synthesis of non-ribosomal peptides is related to this. The influence of cultivation conditions can be assessed by analyzing the gene expression of non-ribosomal peptide synthetases of target NRPs and studying the mechanisms of its regulation. The aim of this study is to investigate the influence of growth medium composition on the expression of non-ribosomal peptide synthetase genes in Bacillus bacteria.

Influence of Growth Medium Composition on Physiological Responses of Escherichia coli to the Action of Chloramphenicol and Ciprofloxacin.

The ability of hydrogen sulfide (H2S) to protect bacteria from bactericidal antibiotics has previously been described. The main source of H2S is the desulfurization of cysteine, which is either synthesized by cells from sulfate or transported from the medium, depending on its composition. Applying electrochemical sensors and a complex of biochemical and microbiological methods, changes in growth, respiration, membrane potential, SOS response, H2S production and bacterial survival under the action of bactericidal ciprofloxacin and bacteriostatic chloramphenicol in commonly used media were studied. Chloramphenicol caused a sharp inhibition of metabolism in all studied media. The physiological response of bacteria to ciprofloxacin strongly depended on its dose. In rich LB medium, cells retained metabolic activity at higher concentrations of ciprofloxacin than in minimal M9 medium. This decreased number of surviving cells (CFU) by 2-3 orders of magnitude in LB compared to M9 medium, and shifted optimal bactericidal concentration (OBC) from 0.3 µg/mL in M9 to 3 µg/mL in LB. Both drugs induced transient production of H2S in M9 medium. In media containing cystine, H2S was produced independently of antibiotics. Thus, medium composition significantly modifies physiological response of E. coli to bactericidal antibiotic, which should be taken into account when interpreting data and developing drugs.

Influence of growth medium composition on the incorporation of boron in HPHT diamond

Influence of growth medium composition on the efficiency of boron doping of carbonado-like diamond at 8–9GPa was studied by diluting the C-B growth system with metallic solvents of carbon, Co and Ni. Addition of these metals to the original system leads to a decrease in the synthesis temperature, degree of doping with boron and suppression of superconductivity in diamond. According to XPS analysis, content of substitutional boron is equal to 0.07, 0.16 and 0.39at.% in diamonds obtained in Co-C-B, Ni-C-B and C-B growth systems, respectively. Metallic behavior at normal temperatures and superconductivity below 5K in diamond, synthesized in C-B system, change to semiconducting character of conductivity down to 2K in diamonds obtained in the diluted systems; a faint hint of superconducting transition at 2K was detected in the case of diamond grown in Ni-C-B system. By comparing phase composition of the inclusions and the doping efficiency of the diamonds, we are able to suggest that high chemical affinity of boron to boride-forming metals hinders the boron doping of diamond. The heavily boron-doped carbonado-like diamond compacts demonstrate high electrochemical activity in aqueous solutions and can be used as miniature electrodes in electrosynthesis and electroanalysis.

Halide-carbon vapor transport of ZnO and its application perspectives for doping with multivalent metals

The growth of ZnO single crystals in closed ampoules using HCl+C mixture as a chemical vapor transport agent (TA) was studied. The influence of growth temperature, TA density, C/HCl ratio, and undercooling on the ZnO mass transport rate was investigated theoretically and experimentally. The influence of growth medium composition on the features of crystal growth, such as the minimization of growth nucleus density, the increase in the lateral growth rate of up to 1 mm per day, the suppression of the attachment effect, and stable growth of non-polar, semi-polar and polar planes of a hexagonal structure was analyzed. The structural, photoluminescent, optical and electrical properties were investigated. The doping efficiency of ZnO by oxides of metals was analyzed for various TAs and Zn pressure in the growth medium. The possibility of increase in the doping efficiency by several orders of magnitude for multivalent metals was predicted for HCl+C TA.

Influence of growth medium composition on synthesis of bioactive compounds and antioxidant properties of selected strains of Arthrospira cyanobacteria

We studied how the selection of the growth medium influences the antioxidant properties and synthesis of bioactive compounds (β-carotene, C-phycocyanin, allophycocyanin, and phycoerythrin) in six selected species of cyanobacteria of Arthrospira genus. For this purpose, cyanobacteria cultures were cultivated on a typical Zarrouk medium and on a cheaper substitute – RM6 medium. Significant differences were observed in the efficiency of synthesis of the studied compounds depending on the strain of cyanobacteria. The quantitative and qualitative composition of Zarrouk medium was more beneficial for β-carotene synthesis in the cells of all strains of cyanobacteria studied. This medium also allowed for the antioxidant potential of the studied strains to be increased. On the other hand, the RM6 medium, deprived of some mineral ingredients, enabled more efficient synthesis of phycobiliproteins in all studied strains except A. platensis SAG 85.79.  

Evaluation of the influence of growth medium composition on cell elasticity

Recently, there has been an increasing interest in using the biomechanical properties of cells as biomarkers to discriminate between normal and cancerous cells. However, few investigators have considered the influence of the growth medium composition when evaluating the biomechanical properties of the normal and diseased cells. In this study, we investigated the variation in Young’s modulus of non-malignant MCF10A and malignant MDA-MB-231 breast cells seeded in five different growth media under controlled experimental conditions. The average Young’s modulus of MDA-MB-231 cells was significantly lower (p<0.0001) than the mean Young’s modulus of MCF10A cells when compared in identical medium compositions. However, we found that growth medium composition affected the elasticity of MCF10A and MDA-MB-231 cells. The average Young’s modulus of both cell lines decreased by 10–18% when the serum was reduced from 10% to 5% and upon addition of epidermal growth factor (EGF, 20ng/ml) to the medium. Though these elasticity changes might have some biological impact, none was statistically significant. However, the elasticity of MCF10A was significantly more responsive than MDA-MB-231 cells to the medium composition supplemented with EGF, cholera toxin (CT), insulin (INS) and hydrocortisone (HC), which are recommended for routine cultivation of MCF10A cells (M5). MCF10A cells were significantly softer (p<0.002) when grown in medium M5 compared to a standard MDA-MB-231 medium (M1). The investigation of the effects of culture medium composition on the elastic properties of cells highlights the need to take these effects into consideration when interpreting elasticity measurements in cells grown in different media.

The influence of growth medium composition and physicochemical factors on biosurfactant production by the bacterium Bacillus licheniformis VKM B-511

The ability of Bacillus licheniformis strain VKM B-511 to grow and synthesize biosurfactants under both aerobic and anaerobic conditions has been demonstrated. Yields of biosurfactants, emulsion indices and surface tension were considerably higher in culture liquor and preparations derived from cultures grown anaerobically at a C/N ratio of 1 : 24, pH 7.0, and temperature of 30 degrees C. Biosurfactant production by B. lichenformis also depended on concentrations of NaCl and Na2S in the medium and on water characteristics, reaching 4.58 g/l for bacteria grown anaerobically on a medium containing anolyte fraction of water.

Influence of growth medium composition on the lipolytic enzyme activity of Ophiostoma piliferum (CartapipTM)

Influence of growth medium composition on the lipolytic enzyme activity of Ophiostoma piliferum (CartapipTM)

Influence of growth medium composition on the lipolytic enzyme activity ofOphiostoma piliferum (CartapipTM)

Production of esterases (carboxyl esterase EC 3.1.1.1) and lipases (glycerol ester hydrolase EC 3.1.1.3) by Ophiostoma piliferum (CartapipTM), a fungus commercialized to decrease fatty acyl esters in wood, is described. The influence of various combinations of carbon and nitrogen sources, in the growth medium, was examined. Medium containing yeast extract as a nitrogen source and olive oil as a carbon source was found to be optimal for extracellular esterase (221 U dm−3) and lipase (152 U dm −3) activities. Further increases in those enzyme activities were achieved by decreasing medium pH from 6.5 to 5.5 (esterase 508 U dm−3; lipase 415 U dm −3) and increasing medium calcium content from 8 m mol dm−3 to 160 m mol dm−3 (esterase 4084 U dm−3; lipase 508 U dm −3) © 1999 Society of Chemical Industry

Influence of substrate and low temperature on growth and survival of verotoxigenic Escherichia coli

Growth and survival of verotoxigenic Escherichia coli(VTEC) were studied in tryptic soy broth (TSB), brain–heart infusion (BHI), and whole milk at 12, 9.5, 8.5, 7.5, 6.5, and 5.5°C (±0.2°C). Colony forming units (cfu) were enumerated by surface plating on eosin methylene blue (EMB) agar plates and incubating at 37°C for 24 h. Growth curves were plotted and lag and generation times were determined. Results indicated that the average generation times for each strain was similar in each medium (4.6±0.9 h) at 12°C. However, at 9.5°C the average generation time differed significantly among the media ( P<0.05). The average generation time was longer in BHI compared to TSB and whole milk at 9.5°C (14 h in BHI vs 11 h in milk and TSB). Also, the generation time of individual strains in BHI varied from 9.5–22 h at 9.5°C. Decrease of temperature to 8.5°C resulted in lack of growth of two strains in BHI. At 7.5°C none of the strains grew in BHI, one grew in TSB, whereas all grew in milk. A further decrease of temperature to 6.5°C did not allow growth of any of the strains in TSB or BHI whereas all grew in milk. Addition of 5% lactose to TSB and BHI enabled survival and growth of all strains at 6.5°C. The results of this study demonstrate the influence of growth medium composition on the minimum growth temperature of verotoxigenic E. coli.

The influence of growth medium composition on the toxicity of chemicals to algae

Algal growth inhibition tests are an important part of monitoring programmes designed to predict the environmental impact of new substances. This study investigated the effects of varying growth medium composition on the toxicity of four chemicals (morpholine, nitrilotriacetic acid, o-dichlorobenzene and triphenyl phosphate) to three species of freshwater green algae recommended for use in standard algal growth inhibition tests: Selenastrum capricornutum, Scenedesmus subspicatus and Chlorella vulgaris. Bold's basal, OECD and EPA media were used. The toxic values obtained from the tests suggest that medium composition significantly affected the sensitivity of the test algae to the four chemicals, but not in a predictable fashion.

Plasmids of Crystal-forming Bacilli and the Influence of Growth Medium Composition on their Appearance

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