Showing papers on "Growth medium published in 1996"
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TL;DR: Results suggest that Smf1p is involved in high-affinity Mn2+ uptake and suggests that in vivo Mas1P is a manganese-dependent peptidase, and resembles a protein from Drosophila and mammalian macrophages.
Abstract: A novel Saccharomyces cerevisiae mutant, unable to grow in the presence of 12.5 mM EGTA, was isolated by replica plating. The phenotype of the mutant is caused by a single amino acid change (Gly149 to Arg) in the essential yeast gene CDC1. The mutant could be suppressed by overexpression of the SMF1 gene, which was isolated as an extragenic high-copy suppressor. The SMF1 gene codes for a highly hydrophobic protein and its deletion renders the yeast cells sensitive to low manganese concentration. In accordance with this observation, the smf1 null mutant exhibits reduced Mn2+ uptake at micromolar concentrations. Using a specific antibody, we demonstrated that Smf1p is located in the yeast plasma membrane. These results suggest that Smf1p is involved in high-affinity Mn2+ uptake. This assumption was also tested by overexpressing the SMF1 gene in the temperature-sensitive mutant of the mitochondrial processing peptidase (MAS1). SMF1 overexpression as well as addition of 1 mM Mn2+ to the growth medium complemented this mutation. This also suggests that in vivo Mas1p is a manganese-dependent peptidase. The yeast Smf1p resembles a protein from Drosophila and mammalian macrophages. The latter was implicated in conferring resistance to mycobacteria. A connection between Mn2+ transport and resistance or sensitivity to mycobacteria is discussed.
320 citations
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147 citations
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TL;DR: Nutritional characteristics of the hyperthermophilic archaeon Thermococcus litoralis have been investigated with emphasis on the development of a sulfur-free, defined growth medium, analysis of an exocellular polysaccharide, and formation of a biofilm.
Abstract: Nutritional characteristics of the hyperthermophilic archaeon Thermococcus litoralis have been investigated with emphasis on the development of a sulfur-free, defined growth medium, analysis of an exocellular polysaccharide, and formation of a biofilm. An artificial-seawater-based medium, containing 16 amino acids, adenine, uracil, vitamins, and trace elements, allowed T. litoralis to attain growth rates and cell densities similar to those found with complex media. Four amino acids (alanine, asparagine, glutamine, and glutamate) were not included due to their lack of effect on growth rates and cell yields. In this medium, cultures reached densities of 10(sup8) cells per ml, with doubling times of 55 min (without maltose) or 43 min (with maltose). Neither the addition of elemental sulfur nor the presence of H(inf2) significantly affected cell growth. A sparingly soluble exopolysaccharide was produced by T. litoralis grown in either defined or complex media. Analysis of the acid-hydrolyzed exopolysaccharide yielded mannose as the only monosaccharidic constituent. This exopolysaccharide is apparently involved in the formation of a biofilm on polycarbonate filters and glass slides, which is inhabited by high levels of T. litoralis. Biofilm formation by hyperthermophilic microorganisms in geothermal environments has not been examined to any extent, but further work in this area may provide information related to the interactions among high-temperature organisms.
138 citations
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TL;DR: These findings are important because they demonstrate that culture conditions can significantly influence the concentration of a biologically active foreign protein secreted from plant cells into the media of suspension cultures.
113 citations
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TL;DR: The ability of amino acids to regulate nitrate uptake and assimilation appears to be more related to their overall levels in the cell rather than to an accumulation of a specific amino acid.
Abstract: The ability of individual amino acids to regulate nitrate uptake and induction was studied in a Zea mays embryo cell line grown in suspension culture. The maize cells exhibited a marked preference for absorbing amino acids over nitrate when both were present in culture medium. The addition of an individual amino acid (2 mM glutamine, glycine, aspartic acid, or arginine) to the culture medium with 1 mM nitrate completely inhibited nitrate uptake and resulted in a cycle of low levels of nitrate influx followed by efflux to the growth medium. Glutamine was readily absorbed by the cells and was particularly effective in supporting optimum cell growth in the absence of an inorganic nitrogen source as compared to the three other amino acids evaluated. However, neither glutamine nor any of the remaining 19 proteinaceous amino acids appeared to be solely responsible for regulation of nitrate uptake and induction. The ability of amino acids to regulate nitrate uptake and assimilation appears to be more related to their overall levels in the cell rather than to an accumulation of a specific amino acid.
69 citations
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TL;DR: A resistant mutant with vancomycin MIC of 100 micrograms/ml was isolated relatively easily through step pressure in the laboratory from a Staphylococcus aureus strain and contained no detectable D-lactate terminating cell wall precursors, indicating the biochemical mechanism and clinical significance of such glycopeptide-resistant mutants remained to be established.
Abstract: A resistant mutant with vancomycin MIC of 100 μg/ml was isolated relatively easily through step pressure in the laboratory from a Staphylococcus aureus strain with initial MIC of 1.5 μg/ml for the antibiotic. Upon addition of vancomycin (50 μg/ml) to the growth medium mass increase of the culture and peptidoglycan synthesis continued but cell division (daughter cell separation), cell wall turnover and autolysis were inhibited, resulting in the production of multicellular clumps of bacteria. Parallel with the increase of culture density, the concentration of vancomycin measured both by biological activity and by HPLC gradually declined in the culture medium. Cell division and wall turnover of the culture resumed with the production of cells of normal morphology at the time when the concentration of the drug in the medium decreased below 0.5–1.0 μg/ml. There was no detectable change in the antibiotic concentration in the culture medium during growth of a vancomycin-resistant (vanA-positive) strain of Enterococcus faecium and an intrinsically vancomycin-resistant strain of Leuconostoc. The vancomycin-resistant staphylococcal mutant gave no signal with the vanA or vanB DNA probes and contained no detectable d-lactate terminating cell wall precursors. The biochemical mechanism and clinical significance of such glycopeptide-resistant mutants remains to be established.
60 citations
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TL;DR: It is proposed that Slfl participates in a copper homeostasis pathway, distinct from the Cup1 detoxification system, that leads to sulfide generation and CuS biomineralization on the cell surface to prevent copper-induced toxicity.
Abstract: In Saccharomyces cerevisiae, at least 12 genes are important for cells to propagate in medium containing elevated concentrations of copper salts (J. Welch, S. Fogel, C. Buchman, and M. Karin, EMBO J. 8:255-260, 1989). Complementation studies were carried out on a copper-sensitive mutation (cup14) from this group. A new yeast gene, designated SLF1, was identified as a multicopy suppressor of the cup14 mutation. Slf1 is important for the physiological process of copper sulfide (CuS) mineralization on the surface of cells cultured in medium containing copper salts. CuS mineralization causes the cells to turn brown. Disruption of SLF1, which is located close to the telomere region of chromosome IV, leads to limited copper sensitivity, and the resulting cells lack the normal brownish coloration when grown in CuSO4-containing medium. Overproduction of Slf1 in wild-type cells confers superresistance to CuSO4 and enhances the coloration of cells cultured in the presence of CuSO4. Upon addition of KCN to Cu-grown cells, the brownish coloration was bleached instantly, and copper ions were solubilized. These data are consistent with Slf1-dependent accumulation of CuS complexes on the cell surface. Disruption of SFL1 also results in loss of the ability of yeast cells to deplete Cu but not Cd ions from the growth medium, whereas overexpression enhances Ca depletion ability and the resulting deposition of CuS particles. It is proposed that Slfl participates in a copper homeostasis pathway, distinct from the Cup1 detoxification system, that leads to sulfide generation and CuS biomineralization on the cell surface. This process may coordinate with the Cup1 pathway at different copper concentrations to prevent copper-induced toxicity.
55 citations
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TL;DR: Experiments were conducted to test the hypothesis that cellular compounds, especially wall-associated compounds, released during emergence of secondary roots, stimulate the growth of arbuscular mycorrhizal fungi, and should increase the probability of contact between fungus and host root.
Abstract: Experiments were conducted to test the hypothesis that cellular compounds, especially wall-associated compounds, released during emergence of secondary roots, stimulate the growth of arbuscular mycorrhizal (AM) fungi. Purified cell walls, crude cell-wall extracts, crude cytoplasmic extracts, and phenolic compounds previously identified as cell wall-associated, from Ri T-DNA-transformed roots of host (Daucus carota L.) and non-host (Beta vulgaris L.) were incorporated into growth medium and tested for their effects upon growth of the AM fungi Gigaspora gigantea (Nicol. & Gerd.) Gerdemann and Trappe and Gigaspora margarita Becker and Hall. Purified cell walls of both plants had little effect on G. gigantea but non-host cell walls inhibited the growth of G. margarita. Ferulic acid, a major constituent of non-host root, depressed the growth of both fungi. Nothing tested which was unique to the non-host root affected hyphal growth to the point that contact would be prohibited. Caffeic acid, found in D. carota cytoplasm, also depressed growth of both fungi. Para-hydroxybenzoic acid, a constituent of D. carota roots, stimulated growth of G. margarita hyphae, but did not affect hyphal growth of G. gigantea. Vanillic acid, unique to D. carota root cell-wall extracts, stimulated hyphal growth and branching of both fungi, and should increase the probability of contact between fungus and host root.
50 citations
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TL;DR: In this paper, the authors showed that the green alga Chlamydomonas reinhardtii acquires the ability to raise its internal inorganic carbon concentration at low CO2.
Abstract: At low-CO2 (air) conditions, the unicellular green alga Chlamydomonas reinhardtii acquires the ability to raise its internal inorganic carbon concentration. To study this adaptation to low CO2, cDNA clones induced under low-CO2 growth conditions were selected through differential screening. One full-length clone is 2552 bp, with an open reading frame encoding 521 amino acids. The deduced amino acid sequence shows about 50% identity with alanine:[alpha]-ketoglutarate aminotransferase (Ala AT, EC 2.6.1.2) from plants and animals, and the mRNA of this clone increased 4- to 5-fold 4 h after cells were switched from high-CO2 to low-CO2 growth conditions. The expression of the enzyme and its activity also increased accordingly at low-CO2 growth conditions. To study the physiological role of Ala AT, a pyridoxal phosphate inhibitor, aminooxyacetic acid, was added at 40 [mu]M to the growth medium when cells were beginning to adapt to low CO2. This caused a 30% decrease in the maximum photosynthetic rate in air-adapting cells 8 h later. The addition of the inhibitor also caused the cells to excrete glycolate, a photorespiratory intermediate, but did not change the apparent affinity of the cell for external CO2. These physiological studies are consistent with the assumption that Ala AT is involved in the adaptation to low-CO2 conditions.
49 citations
01 Jan 1996
TL;DR: In this paper, the authors showed that increasing NaCl concentrations in the growth medium inhibited the growth of Desulfovibrio halophilus due to both an increase in the lag phase of growth and a reduction in the specific growth rate.
Abstract: Increasing NaCl concentrations in the growth medium inhibited the growth of Desulfovibrio halophilus due to both an increase in the lag phase of growth and a reduction in the specific growth rate. Addition of 1 mh4 glycine betaine to the growth medium partially relieved this inhibition. Natural abundance 13C nuclear magnetic resonance spectroscopy identified the disaccharide a-a trehalose and glycine betaine as the major organic solutes accumulated by D. halophilus during growth in mineral salts medium and mineral salts medium supplemented with 1 mh4 glycine betaine, respectively. The presence of a weak glycine betaine transport system was confirmed by following the accumulation of [methyl-‘4C]glycine betaine during osmotic upshock. In the absence of exogenous glycine betaine the intracellular trehalose concentration of D. hulophilus was dependent upon the osmolarity of the growth medium, with a maximum concentration of 8.3 p,mol trehalose mg protein- ’ recorded in cultures grown in the presence of 15% w/v NaCl. Intracellular K+ concentrations were also dependent upon the osmolarity of the growth medium over the range 3-9% w/v NaCl, but showed little further increase at higher NaCl
45 citations
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TL;DR: In this article, the authors showed that increasing NaCl concentrations in the growth medium inhibited the growth of Desulfovibrio halophilus due to both an increase in the lag phase of growth and a reduction in the specific growth rate.
Abstract: Increasing NaCl concentrations in the growth medium inhibited the growth of Desulfovibrio halophilus due to both an increase in the lag phase of growth and a reduction in the specific growth rate. Addition of 1 mM glycine betaine to the growth medium partially relieved this inhibition. Natural abundance 13C nuclear magnetic resonance spectroscopy identified the disaccharide α-α trehalose and glycine betaine as the major organic solutes accumulated by D. halophilus during growth in mineral salts medium and mineral salts medium supplemented with 1 mM glycine betaine, respectively. The presence of a weak glycine betaine transport system was confirmed by following the accumulation of [methyl-14C]glycine betaine during osmotic upshock. In the absence of exogenous glycine betaine the intracellular trehalose concentration of D. halophilus was dependent upon the osmolarity of the growth medium, with a maximum concentration of 8.3 μmol trehalose mg protein−1 recorded in cultures grown in the presence of 15% w/v NaCl. Intracellular K+ concentrations were also dependent upon the osmolarity of the growth medium over the range 3–9% w/v NaCl, but showed little further increase at higher NaCl concentrations.
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TL;DR: A protein-free growth medium for NS0 cells expressing humanised monoclonal antibody using GS (glutamine synthetase) as a selectable marker is described and CAMPATH-1H antibody produced using serum-free medium was found to be functionally activein vitro in the Antibody Dependant Cellular Cytotoxicity assay.
Abstract: A protein-free growth medium (W38 medium) had previously been developed for the NS0 mouse myeloma cell line which is cholesterol-auxotrophic. This paper describes the development of a protein-free growth medium for NS0 cells expressing humanised monoclonal antibody using GS (glutamine synthetase) as a selectable marker. Several GS-engineered NS0 cell lines expressing humanised monoclonal antibody grew in a modification of W38 medium which maintained GS-selection, supplemented with cholesterol, phosphatidylcholine and β-cyclodextrin. Further studies showed that additional glutamic acid, asparagine, ribonucleosides and choline chloride improved cell growth. Amino acid analysis identified a number of amino acids that were being depleted from the culture medium. NS0 cell lines 9D4 and 2H5 expressing CAMPATH-1H* were adapted to enable them to grow serum-free in the absence of cholesterol and β-cyclodextrin. Cholesterol-independent 9D4 (9D4.CF) cells grown in shake flask culture using an enriched protein-free medium (WNSD medium), supplemented with human recombinant insulin (Nucellin), reached a maximum cell density to 1.86×106 cells ml−1 producing 76.6 mg l−1 of antibody. CAMPATH-1H antibody produced using serum-free medium was found to be functionally activein vitro in the Antibody Dependant Cellular Cytotoxicity (ADCC) assay.
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TL;DR: Pseudomonas strains were found to be more resistant to apolar solvents than all other bacteria tested, and this resistance was dependent not only on the polarities but also on the toxic nature of different organicsolvents, the cell membrane components, and to a limited extent, the growth medium.
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TL;DR: An intronless form of the bgl1 gene encoding an extracellular β-glucosidase from Trichoderma reesei was expressed in the yeast Saccharomyces cerevisiae under the control of the yeast GAL1 promoter.
Abstract: An intronless form of the bgl1 gene encoding an extracellular β-glucosidase from Trichoderma reesei was expressed in the yeast Saccharomyces cerevisiae under the control of the yeast GAL1 promoter. Transformation of a yeast strain with this vector resulted in transformants that produce and secrete active β-glucosidase into the growth medium. Additionally, active recombinant β-glucosidase protein was shown to be localized predominantly in the periplasmic space by using a p-nitrophenyl β-D-glycoside hydrolysis assay against fractionated yeast cells. The apparent size of the recombinant enzyme was 10–15 kDa larger than that of the native form. Treatment of the recombinant β-glucosidase with endoglycosidase-H indicated the apparent increase in size was due to N-linked glycosylation.
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TL;DR: The level of eicosapentaenoic acid seemed exclusively dictated by growth temperature, suggesting that the synthesis of this polyunsaturated fatty acid may be a key regulatory process in maintaining membrane fluidity.
Abstract: The influence on fatty acid composition of growth medium composition and phase of growth during batch culture and of dilution rate and growth temperature during continuous culture was studied in the eicosapentaenoic-acid (20:5 n-3)-producing Vibrio CCUG 35308. In glucose-mineral medium, even-numbered normal fatty acyl residues, primarily 16:0, 16:1, 18:1, and 20:5, strongly dominated (ca. 90%), and the fatty acid profile remained practically unchanged throughout a batch-growth cycle. In nutrient broth, the contribution by “uncommon” fatty acids, mainly i-13:0, 15:0, i-15:0, and 17:1 was generally higher, and increased from 15.4% of total fatty acids in early exponential growth phase to 33.2% in the stationary phase. Reduction of the dilution rate in a chemostat from 0.27 to 0.065 h–1 also led to an almost threefold increase in the proportion of odd-numbered residues at the expense of the even-numbered normal ones. Contrary to this plasticity in the overall fatty acid profile influenced by variations in nutrient composition and availability, the level of eicosapentaenoic acid seemed exclusively dictated by growth temperature. The synthesis of this polyunsaturated fatty acid may be a key regulatory process in maintaining membrane fluidity.
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TL;DR: It is hypothesized that during growth on glucose, both modulation of the kinetics of glucose uptake and derepression of invertase activity require the presence of more than one active gene of the glucose transporter family.
Abstract: The kinetics of glucose transport in a number of different mutants ofSaccharomyces cerevisiaewith multiple deletions in the glucose transporter gene family were determined. The deletions led to differences in maximal rate and affinity for glucose uptake by the cells, dependent on the growth conditions. At the same time, there were changes in glucose repression, as determined by expression of invertase activity. Only in the strain with genes HXT1-4 and SNF3 deleted but carrying HXT6/7 were glucose uptake kinetics and invertase activity independent of the presence or concentration of glucose in the growth medium. Some degree of glucose sensitivity was recovered if the SNF3 or HXT2 gene was present in the multiple-deletion background. It is hypothesized that during growth on glucose, both modulation of the kinetics of glucose uptake and derepression of invertase activity require the presence of more than one active gene of the glucose transporter family. Saccharomyces cerevisiae cells growing on glucose in batch culture exhibit an increase in affinity for glucose as the glucose in the medium is consumed, while the maximal rate of glucose transport under such conditions is constant (16). When cells growing on a high concentration of glucose (2%) are transferred to a medium containing a low concentration of glucose (0.1%), however, a similar increase in affinity for glucose is observed,buttheaffinitychangeisaccompaniedbyanincrease in the maximal rate of glucose uptake (2). This complex behaviorismostlikelytheresultofanumberoffactors,including
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TL;DR: Using a mass balance approach and Monod growth kinetics a model is presented which describes the fed-batch culture of Phaffia rhodozyma and enables the calculation of a feed regime to obtain the maximum yield of cells and pigment.
Abstract: As Phaffia rhodozyma is a Crabtree positive yeast, its cell yield and pigment production are reduced at high sugar concentrations. A method for maintaining low growth medium sugar concentrations is fed-batch culture. Using a mass balance approach and Monod growth kinetics a model is presented which describes the fed-batch culture of Phaffia rhodozyma and enables the calculation of a feed regime to obtain the maximum yield of cells and pigment. Although developed on a glucose medium, the model was also applied successfully to a molasses-based medium.
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TL;DR: Northern blot analysis using homologous probe binding to total RNA preparations revealed that reduction in specific activity was paralleled by repression of the corresponding gene.
Abstract: Physiological concentrations of ethylene in the growth medium of autotropic suspension culture Chenopodium rubrum L. cells reduced the activity of cell wall bound invertase by 25 – 47%, compared to controls. Northern blot analysis using homologous probe binding to total RNA preparations revealed that reduction in specific activity was paralleled by repression of the corresponding gene.
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TL;DR: TGYA was judged best among selective media for enumerating Z. bailii because of its ability to support colony development by heat-stressed cells and because of the ease of counting and differentiating colonies.
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TL;DR: The volumetric and specific activities of Streptomyces viridosporus T7A lignin peroxidase isoform ALiP‐P3 were increased by formulating a novel corn‐starch‐based growth medium by optimizing the concentrations of starch, casein, yeast extract, CaCO3, NH4Cl, and trace metals.
Abstract: The volumetric and specific activities of Streptomyces viridosporus T7A lignin peroxidase isoform ALiP-P3 were increased by formulating a novel corn-starch-based growth medium by optimizing the concentrations of starch, casein, yeast extract, CaCO3 ,N H 4Cl, and trace metals. This medium increases cell densities by 10-fold, cell-specific ALiP-P3 activity by 6-fold, and volumetric ALiP-P3 activity by 60-fold compared to those obtained using a yeast-extract-based medium. The presence of increased concentrations of ALiP-P3 in the starch-based cultures was confirmed by Western blot analysis. In addition, the lignin peroxidase activity was found to be highly dependent upon the concentration of the necessary cofactor, hydrogen peroxide; using 2,4-dichlorophenol as the substrate, ALiP-P3 activity increased 1448-fold as the concentration of H2O2 was varied from 0.1 to 250 mM.
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TL;DR: The symptoms of witches' broom disease in cocoa, caused by the Basidiomycete fungus Crinipellis perniciosa, are pronounced swelling of the terminal and axillary buds followed in the long term by necrosis of this tissue.
Abstract: The symptoms of witches' broom disease in cocoa, caused by the Basidiomycete fungus Crinipellis perniciosa, are pronounced swelling of the terminal and axillary buds followed in the long term by necrosis of this tissue. The direct effect of C. perniciosa on cocoa cells was examined under controlled conditions by growing primary and secondary phase cultures of the fungus separately and also with callus cultures and with cell suspensions. Both primary and secondary phase mycelium reduced growth of callus cultures by about 47% after one week compared with the controls. However, cell suspensions containing primary phase mycelium showed initial growth double that of the uninfected controls after 5 days, but then growth was reduced below that of the control and particularly when the primary phase became secondary phase mycelium. This change in fungal development coincided with the time that the cell culture reached the stationary growth stage. Cell cultures inoculated with stationary phase mycelium showed the same growth as the control after 5 days but then growth was reduced to 50% of the control after 19 days incubation and remained at this low level subsequently. The inhibitory effect of secondary phase mycelium was examined by incubating callus and cell suspensions with culture filtrate from liquid cultures of the secondary phase. Inclusion of 50% by volume of culture filtrate from the secondary phase in the growth medium for callus and cell suspensions, respectively, resulted in a reduction in growth of the plant tissue cultures. Addition of fungal culture filtrates also led to loss in potassium and loss of viability of cell suspensions and of isolated cells as represented by protoplasts. The necrotrophic mode of the secondary phase may be achieved through the production of phytotoxins acting on the host cell membrane.
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TL;DR: The influence of the ammonium-glucose ratio on exopolysaccharide (EPS) production and morphology of Aureobasidium pullulans was studied in continuous cultivations.
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TL;DR: Phosphate concentration of the growth medium was found to affect the growth rate and agar yield of a clone of Gelidium robustum grown in the laboratory, and starch yield was highest in algae grown in low phosphate concentrations.
Abstract: Phosphate concentration of the growth medium was found to affect the growth rate and agar yield of a clone of Gelidium robustum grown in the laboratory. To study differences in growth we used phosphate concentrations from 0 to 200 µM. To determine the effect of phosphate on agar yield and its properties we used concentrations from 0 to 20 µM. Growth rates generally increased with increasing phosphate concentration, with the highest growth rate (21% d-1) obtained at 150 µM. Agar yield as percentage of fresh weight was highest (10%) in the algae grown with low phosphate concentrations, but agar yield as percentage of dry weight was highest(43%) at 20 µM of phosphate. Gel strength increased with phosphate concentration with a maximum of 160 g m-2 for 0.75% gels for the cultures at 20 µM. Melting and gelling temperatures of the gels were also affected by phosphate concentration of the growth medium. Starch yield was highest in algae grown in low phosphate concentrations.
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TL;DR: Fungal growth data suggest that postharvest mycelial growth of Botrytis cinerea and Alternaria alternata on wounds, senescing tissue or secretions such as cell sap or nectar could be restricted through control of e.r.h. in packages of horticulture produce.
Abstract: Mycelial growth in vitro of 2 fungal pathogens responsible for postharvest loss of horticulture produce, Botrytis cinerea and Alternaria alternata, was related to equilibrium relative humidity (e.r.h) at ambient temperature (20¦C) using solutes to adjust the 'osmotic water potential' of the growth medium. Colony diameter growth of B. cinerea and A. alternata on solid medium (1/2 potato dextrose agar) was initially stimulated slightly when the e.r.h. was decreased from 99.7 (unamended medium) to 99.3% (-0.4 to -1.0 MPa). Thereafter, colony diameter growth continually decreased as a function of reducing e.r.h. over the range 99.3-94.3% e.r.h. (-1.0 to -8.0 MPa). Similar trends were recorded with both pathogens for their dry matter growth in liquid medium (Oxoid Czapek Dox) as a function of osmotic potential. Initial stimulation of dry matter growth at -1.0 MPa (equivalent to 99.3% e.r.h.) was not evident in liquid medium. Fungal growth data suggest that postharvest mycelial growth of Botrytis cinerea and Alternaria alternata on wounds, senescing tissue or secretions such as cell sap or nectar could be restricted through control of e.r.h. in packages of horticulture produce.
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TL;DR: Extracellular and intracellular aminopeptidases were produced from Lactobacillus casei ssp.
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TL;DR: It was shown that the cytotoxicity of adriamycin is markedly dependent on the presence of iron in each type of cell, and BPS and ascorbate reduced and competed for iron in Fe(III) transferrin to form Fe(II)(BPS)3.
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TL;DR: Use of standard transport medium with subsequent transfer into selective growth medium results in a significantly decreased yield of positive group B Streptococcus cultures.
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TL;DR: Growth and cellulolytic en?
Abstract: Saccobolus saccoboloides was grown in a liq? uid synthetic medium with crystalline cellulose as the only carbon source. Culture supernatant was used to measure activities of the enzymes of the cellulolytic complex: (3-1,4 endoglucanase, (3-1,4 exoglucanase and p-glucosidase. The kinetics of growth and en? zyme production were studied in static and shaken cultures. The influence of various nitrogen sources, on production of the various cellulases in the culture medium was investigated. Growth and cellulolytic en? zymes production were maximal when organic ni- trogenous compounds were supplied. Enzymatic pro? duction was maximal at an initial pH of the growth medium of 6.5. Enzymatic activities were favored in the range of 50-55 C and pH 4.8-5.4.
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TL;DR: High cell density cultivations under partial nitrogen limitation decreased proteolysis of recombinant proteins, therefore reduced amounts of proteases are considered to be responsible.
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TL;DR: The enriched medium based on yeast nitrogen basc(YNB) increased hirudin synthesis and secretion in rccombinant Saccharomyces cerevisiae in batch and fed-batch cultures and produced the product protein with higher purity of 21% and hence will allow easy separation of secreted hirUDin from other contaminated polypeptides present in the growth medium.
Abstract: The enriched medium based on yeast nitrogen basc(YNB)increased hirudin synthesis and secretion in rccombinant Saccharomyces cerevisiae in batch and fed-batch cultures. Fed-batch fermentation with the defined medium yielded 342mg hirudin/l but supplementation of yeast extract increased the final hirudin concentration to 461mg hirudin/l. The defined medium, however, produced the product protein with higher purity of 21% and hence will allow easy separation of secreted hirudin from other contaminated polypeptides present in the growth medium. In a continuous culuture, the defined medium yielded higher concentrations of cell mass and hirudin than the complex medium.