scholarly journals STUDIES ON THE METABOLISM OF STREPTOMYCES GRISEUS IN RELATION TO THE PRODUCTION OF STREPTOMYCIN

1948 ◽  
Vol 26c (2) ◽  
pp. 164-173 ◽  
Author(s):  
H. M. Eiser ◽  
W. D. McFarlane
Keyword(s):  
Sodium Chloride ◽  
Growth Factor ◽  
Synthetic Medium ◽  
Streptomyces Griseus ◽  
Cellular Membrane ◽  
High Concentration ◽  
Nutrient Media ◽  
Mycelium Growth ◽  
Lyotropic Series ◽  
Amino Acid Combination

A synthetic medium inducing high streptomycin production was evolved by studying growth factor and nitrogen requirements of the mold Streptomyces griseus. It was concluded that mycelium growth and streptomycin production do not necessarily parallel each other. Histidine appeared to affect both streptomycin and mycelium formation and was essential in any amino acid combination to induce either a high mycelium or streptomycin yield. Valine was shown to stimulate streptomycin synthesis and aspartic or glutamic promoted only mycelium production. Experiments were done to show which metabolic changes in the medium could be associated with growth and which with the antibiotic production.The effect on the mold of high concentration of sodium chloride was investigated. It was found that by reducing the amount of salt in the nutrient media, the greater part of the streptomycin could be recovered from the mycelium instead of the medium. It appears that the antibiotic is a product of intracellular synthesis, since ions of the lyotropic series affecting the permeability of the cellular membrane affect the distribution of the antibiotic between medium and mycelium.

Growth of isolated Phycomyces sporangiophores on nutrient media and simple sugars

1968 ◽  
Vol 46 (3) ◽  
pp. 247-254 ◽  
Author(s):  
Hans E. Gruen
Keyword(s):  
Growth Factor ◽  
Synthetic Medium ◽  
Phycomyces Blakesleeanus ◽  
Nutrient Media ◽  
Synthetic Media

Growth of isolated Phycomyces blakesleeanus sporangiophores was not promoted relative to growth on water either by a synthetic medium with two concentrations of dextrose or by concentrated and dilute potato dextrose solutions. A range of sucrose and dextrose concentrations also failed to promote growth. On the contrary, the more concentrated nutrient media and the pure sugar solutions at 0.08 M and higher reduced the final sporangiophore length measured after 64 h. The inhibition on dextrose was directly proportional to concentration up to about 0.7 M and increased more sharply at higher concentration, becoming complete at close to 1 M. At 0.9 M the incidence of branching was greatly increased. Sucrose caused almost the same inhibition as dextrose up to 0.3 M. On complete nutrient media, but not on water, considerable regeneration of mycelium occurred at the sporangiophore base, and the amount regenerated was greater on potato than on synthetic media. Sporangiophore growth was not influenced by the regenerated mycelium. Differences between the submerged regenerated mycelium and surface mycelium are pointed out. Growth of isolated sporangiophores was not affected by pH between 3 and 7.6, but pH 2 caused limited inhibition. The evidence suggests that a factor limiting the growth of the deficient isolated sporangiophores is normally supplied by the mycelium but is not a nutrient or growth factor present in media which support growth of mycelium with sporangiophores.

scholarly journals Improvement on filterability in the aerobic treatment of carboxymethyl cellulose (CMC) wastewater

2014 ◽  
Vol 20 (4) ◽  
pp. 491-501
Author(s):  
Pei Qing ◽  
Chen Hui ◽  
Zhou Ming ◽  
Lu Qin ◽  
Ma Qiang
Keyword(s):  
Sodium Chloride ◽  
Membrane Fouling ◽  
Aerobic Treatment ◽  
Treatment Efficiency ◽  
High Concentration ◽  
Low Concentration ◽  
Chemically Modified ◽  
Natural Cellulose ◽  
Salinity Shock ◽  
Filtration Flux

CMC is chemically modified from natural cellulose and widely applied in various industries. CMC wastewater consists mainly of sodium glycolate, sodium chloride and water. With extremely high COD and salinity, high concentration CMC wastewater can?t be biologically treated, but with COD and salinity around 15000 mg/L and 30000 mg/L respectively, low concentration CMC wastewater can be aerobically treated. In a CMC factory, the treatment of low concentration wastewater with aerobic MBR was successful except for one serious problem: poor filterability. Two trial solutions: adding micronutrients and applying MBBR were expected to improve the filterability. In the experiment, adding micronutrients was achieved by mixing filtered natural water into the wastewater, rather than dosing chemicals into it. The treatment efficiency of both solutions was close, but adding micronutrients showed distinguished performance in improving filterability, which includes higher filtration flux and slighter membrane fouling. Adding micronutrients also effectively improved the filterability under severe salinity shock.

scholarly journals The effects of IGF-I on bovine follicle development and IGFBP-2 expression are dose and stage dependent

Reproduction ◽  
2006 ◽  
Vol 131 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Kirsty A Walters ◽  
John P Binnie ◽  
Bruce K Campbell ◽  
David G Armstrong ◽  
Evelyn E Telfer
Keyword(s):  
Growth Factor ◽  
Granulosa Cells ◽  
Size Range ◽  
Regulatory System ◽  
Follicular Development ◽  
High Dose ◽  
Insulin Like Growth Factor ◽  
High Concentration ◽  
Antral Follicles ◽  
Igf I

This study aimed to determine the effect of insulin-like growth factor-I (IGF-I) on early antral bovine follicular development, and the expression of insulin-like growth factor-binding protein-2 (IGFBP-2). Antral follicles separated into three different size groups were cultured for 6 days in medium supplemented with either a low (10 ng/ml) or high (1 μg/ml) dose of human recombinant IGF-I. Oestradiol production by follicles in all size ranges, cultured in the presence of the high concentration of IGF-I, significantly increased by day 6 (P < 0.05). Follicles in the smallest size range, 165–215 μm, cultured in a high dose of IGF-I, were found to be significantly increased in size (P < 0.01). Oocyte health of the largest follicles (281–380 μm) was significantly improved by the addition of IGF-I to the culture medium. mRNA expression of IGFBP-2 was decreased in the granulosa cells of follicles, size range 216–280 μm, cultured with a high dose of IGF-I (P < 0.05). Granulosa cells (P < 0.05) and oocytes (P < 0.01) of the largest follicles (281–380 μm) showed a decrease in IGFBP-2 expression (protein) when cultured in the control and low-IGF-I treatment groups. Therefore, the response of a bovine follicle to IGF-I is both dose and stage dependent. This work supports a role for IGF-I in modulating somatic and germ-cell maturation and development in early antral follicles. Furthermore, the inverse relationship between the level of IGF-I stimulation and IGFBP-2 expression suggests a local regulatory system modulating IGF-I availability.

Internalization of activated platelet-derived growth factor receptor-phosphatidylinositol-3' kinase complexes: potential interactions with the microtubule cytoskeleton

1993 ◽  
Vol 13 (10) ◽  
pp. 6052-6063
Author(s):  
R Kapeller ◽  
R Chakrabarti ◽  
L Cantley ◽  
F Fay ◽  
S Corvera
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Endocytic Pathway ◽  
Platelet Derived Growth Factor ◽  
Cell Periphery ◽  
Perinuclear Region ◽  
High Concentration ◽  
Microtubule Cytoskeleton ◽  
Microtubule Network

Phosphatidylinositol (PI)-3' kinase catalyzes the formation of PI 3,4-diphosphate and PI 3,4,5-triphosphate in response to stimulation of cells by platelet-derived growth factor (PDGF). Here we report that tyrosine-phosphorylated PDGF receptors, the p85 subunit of PI-3' kinase (p85), and activated PI-3' kinase are found in isolated clathrin-coated vesicles within 2 min of exposure of cells to PDGF, indicating that both receptor and activated PI-3' kinase enter the endocytic pathway. Immunofluorescence analysis of p85 in serum-starved cells revealed a punctate/reticular staining pattern, concentrated in the perinuclear region and displaying high focal concentration at the centrosome. In addition, partial coalignment of p85 with microtubules was observed after optical sectioning microscopy and image reconstruction. The association of p85 with the microtubule network was further evidenced by the microtubule-depolymerizing drug nocodazole, which caused a redistribution of p85 from the perinuclear region to the cell periphery. Interestingly, the most significant effect of PDGF on the distribution of p85 was an increase in the staining intensity of this protein in the perinuclear region, and this effect was eliminated by prior treatment of cells with nocodazole. These results suggest that PDGF receptor-p85 complexes internalize and transit in association with the microtubule cytoskeleton. In addition, the high concentration of p85 in intracellular structures in the absence of PDGF stimulation suggests additional roles for this protein independent of its association with receptor tyrosine kinases.

The role of sodium chloride in the process of induction by lithium chloride in cells of the Rana pipiens gastrula

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 387-396
Author(s):  
Lester G. Barth ◽  
Lucena J. Barth
Keyword(s):  
Sodium Chloride ◽  
Culture Medium ◽  
Rana Pipiens ◽  
Divalent Cations ◽  
Pigment Cells ◽  
Distilled Water ◽  
Sodium Ions ◽  
Monovalent Cations ◽  
High Concentration

A study of the effects of a series of monovalent cations, Li+, Na+ and K+, and a series of divalent cations, Mn2+, Ca2+ and Mg2+, upon small aggregates of cells taken from the presumptive epidermis of Rana pipiens gastrulae revealed that these ions induce nerve and pigment cells (Barth, 1965). The effectiveness of both series of ions as inductors was similar to their effects on decreasing the electrophoretic mobility of DNA as determined by Ross & Scruggs (1964). When it was found that sucrose in glass-distilled water also would induce nerve and pigment cells the role of ions as inductors came under closer scrutiny. A study of the nature of the induction by sucrose revealed that a relatively high concentration of sodium ions was necessary in the culture medium used after sucrose treatment (Barth, 1966).

Corrosion of Amorphous Fe73.5Si13.5B9Nb3Cu1 Alloys on the Synergistic Effect of Chloride and Hydroxyl Ions

2011 ◽  
Vol 284-286 ◽  
pp. 1550-1553
Author(s):  
Ming Sheng Li ◽  
Dan Zhang ◽  
Yi Ming Jiang ◽  
Jin Li
Keyword(s):  
Magnetic Properties ◽  
Electrochemical Impedance Spectroscopy ◽  
Sodium Chloride ◽  
Impedance Spectroscopy ◽  
Service Life ◽  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Soft Magnetic Properties ◽  
High Concentration ◽  
Soft Magnetic

The soft-magnetic properties and service life of amorphous or nanocrystalline Fe73.5Si13.5B9Nb3Cu1 have been influenced by the corrosion of the alloy. In this study, the electrochemical corrosions of amorphous Fe73.5Si13.5B9Nb3Cu1 in the blend solutions of sodium chloride and sodium hydroxide were investigated by linear polarization (PLZ) and electrochemical impedance spectroscopy (EIS) technique. The presence of OH- in the blend solution gave rise to typical passivation of the alloy. A suitable concentration of OH- was required for the low corrosion rate. And the higher concentration of OH- led to a faster corrosion. Increase of concentration of Cl- aroused more obvious corrosion. These results were ascribed to the deteriorating effect of Cl- and high-concentration OH- on the passive film formed on the surface of amorphous Fe73.5Si13.5B9Nb3Cu1.

Late signals are required for the stimulation of DNA synthesis in rat mammary fibroblasts by growth factors

1996 ◽  
Vol 16 (3) ◽  
pp. 249-263 ◽  
Author(s):  
Hai-Lan Chen ◽  
Philip S. Rudland ◽  
John A. Smith ◽  
David G. Fernig
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Maximal Response ◽  
High Concentration ◽  
Initial Concentration ◽  
Maximal Stimulation ◽  
Epidermal Growth ◽  
Lag Period ◽  
Stimulation Of

Maximal stimulation of DNA synthesis in quiescent rat mammary (Rama) 27 fibroblasts is elicited by epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF) 18 h after the initial addition of the growth factors-the ‘lag’ period. At maximally-stimulating concentrations, EGF and bFGF are interchangeable 9 h after their initial addition. When the initial concentration of growth factor is below that required to elicit a maximal response, it is possible to increase the level of DNA synthesis by increasing the concentration of growth factor 9 h after its initial addition. When the initial concentration of growth factor is high, substitution by a lower concentration of growth factor after 9 h allows a greater proportion of cells to synthesize DNA than would be expected from a continuous low dose of growth factor. Similar results are obtained when both the growth factor and its concentration are changed 9 h after the initial addition of growth factor. However, when EGF at a low concentration is substituted for a high concentration of EGF or bFGF the resulting increase in the levels of DNA synthesis is greater when EGF rather than bFGF is added for a second time. The half-life of the growth-stimulatory signals delivered by EGF and by bFGF 9 h after their initial addition is 1–2 h. These results suggest that to stimulate DNA synthesis: (i) EGF or bFGF must deliver a signal(s) continuously; (ii) the initial signals produced by EGF and bFGF are equivalent; (iii) the signals produced between 9–18 h by EGF may be different to those produced by bFGF.

scholarly journals Assessment of Vascular Endothelial Growth Factor in Fresh versus Frozen Platelet Rich Plasma

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Nada Hosny ◽  
Fikry Goubran ◽  
Basma BadrEldin Hasan ◽  
Noha Kamel
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Calcium Gluconate ◽  
Platelet Rich Plasma ◽  
Vascular Endothelial ◽  
High Concentration ◽  
Significant Difference ◽  
Growth Factor Release ◽  
Endothelial Growth Factor ◽  
Vegf Release

Platelet rich plasma (PRP) is hemoconcentration with platelets concentration above baseline values and high concentration of many growth factors. The aim of this study was to assess freezing effect on vascular endothelial growth factor (VEGF) release from PRP using two different activation methods to simplify its use in different clinical applications. PRP was prepared using two-centrifugation steps method from 12 qualified blood donors. VEGF concentrations were measured in fresh PRP and after freezing/thawing for one and three weeks with two methods of activation using (i) calcium gluconate and (ii) calcium gluconate and thrombin. Platelets count was significantly increased compared to baseline whole blood values in all fresh and frozen PRP samples (p value was <0.05). No significant difference was found between VEGF concentrations after activating fresh and frozen-thawed PRP samples for one and three weeks by calcium alone or calcium with thrombin, and also no significant difference was found when freezing period was extended from one to three weeks. Our results showed that platelets count does not correlate with variable levels of VEGF. PRP could be prepared once and preserved frozen for at least three weeks for the next treatment sessions and activation with thrombin addition to calcium will not augment the growth factor release.

scholarly journals Destruction of Polyelectrolyte Microcapsules Formed on CaCO3 Microparticles and the Release of a Protein Included by the Adsorption Method

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 520
Author(s):  
Egor V. Musin ◽  
Aleksandr L. Kim ◽  
Sergey A. Tikhonenko
Keyword(s):  
Sodium Chloride ◽  
Ionic Strength ◽  
Ammonium Sulfate ◽  
Fluorescein Isothiocyanate ◽  
Total Protein Content ◽  
High Concentration ◽  
Adsorption Method ◽  
Polyelectrolyte Microcapsules ◽  
High Level ◽  
Increasing Temperature

The degradation of polyelectrolyte microcapsules formed on protein-free CaCO3 particles consisting of polyallylamine (PAH) and polystyrene sulfonate (PSS) and the resulting yield of protein in the presence of various salts of different concentrations, as well as at two pH values, was studied by fluorescence spectroscopy; the protein was incorporated into prepared microcapsules by adsorption. It was found that a high concentration of sodium chloride (2 M) leads to considerable dissociation of PAH, which is apparently due to the loosening of polyelectrolytes under the action of ionic strength. At the same time, 0.2 M sodium chloride and ammonium sulfate of the same ionic strength (0.1 M) exert less influence on the amount of dissociated polymer. In the case of ammonium sulfate (0.1 M), the effect is due to the competitive binding of sulfate anions to the amino groups of the polyelectrolyte. However, unlike microcapsules formed on CaCO3 particles containing protein, the dissociation of polyelectrolyte from microcapsules formed on protein-free particles increased with increasing temperature. Apparently, a similar effect is associated with the absence of a distinct shell, which was observed on microcapsules formed on protein-containing CaCO3 particles. The high level of the presence of Fluorescein isothiocyanate (FITC)-labeled Bovine Serum Albumin (BSA) in the supernatant is explained by the large amount of electrostatically bound protein and the absence of a shell that prevents the release of the protein from the microcapsules. In 2 M NaCl, during the observation period, the amount of the released protein did not exceed 70% of the total protein content in the capsules, in control samples, this value does not exceed 8%, which indicates the predominantly electrostatic nature of protein retention in capsules formed on protein-free CaCO3 particles. The increase in protein yield and peeling of PAH with increasing pH is explained by the proximity of pH 7 to the point of charge exchange of the amino group of polyelectrolyte, as a result of the dissociation of the microcapsule.

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