scholarly journals Glycosidases from the culture medium of Physarum polycephalum

1977 ◽  
Vol 161 (1) ◽  
pp. 149-158 ◽  
Author(s):  
D C Kilpatrick ◽  
J L Stirling
Keyword(s):  
Stationary Phase ◽  
Growth Curve ◽  
Physarum Polycephalum ◽  
Culture Medium ◽  
Axenic Culture ◽  
Electrophoretic Separation ◽  
Axenic Culture Medium

Eight exo-glycosidase activities were detected in the axenic culture medium of the myxomycete, Physarum polycephalum. The secretion of each enzyme examined followed the growth curve and continued during the stationary phase after the cessation of growth. Two or more forms of each enzyme were detected after electrophoretic separation. The beta-N-acetyl-D-hexosaminidase activity was readily separated into its two electrophoretic forms, X and Y, which were purified 145- and 306-fold respectively. These beta-N-acetyl-D-hexosaminidases had several similar characteristics. Evidence is presented that the major electrophoretic form of alpha-D-galactosidase is heterogeneous. The possible functions of extracellular glycosidases in teir occurrence and properties.

Volatile Ketones and Alcohols of Codworms (Terranova decipiens) from Axenic Culture and Fresh Fish Muscle

1976 ◽  
Vol 33 (12) ◽  
pp. 2819-2821 ◽  
Author(s):  
R. G. Ackman
Keyword(s):  
Chromatographic Analysis ◽  
Culture Medium ◽  
Axenic Culture ◽  
Fish Muscle ◽  
Fresh Fish ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Axenic Culture Medium

Simple techniques for the gas–liquid chromatographic analysis of volatile ketones and alcohols from cultures or native codworms, Terranova decipiens, or from the axenic culture medium, are described. Three ketones (propanone-2, butanone-2, pentanone-3) and two alcohols (butanol-2, pentanol-3) were observed. The proportion of alcohols to ketones was different in culture medium and in native worms from cod, but the latter were qualitatively and quantitatively similar in fresh cod taken in March and September.

Poly(β-L-malate) hydrolase from Plasmodia of Physarum polycephalum

1995 ◽  
Vol 41 (13) ◽  
pp. 192-199 ◽  
Author(s):  
Christian Korherr ◽  
Michael Roth ◽  
Eggehard Holler
Keyword(s):  
Hydrophobic Interaction ◽  
Malic Acid ◽  
Physarum Polycephalum ◽  
Culture Medium ◽  
Specific Activity ◽  
Hydrophobic Interaction Chromatography ◽  
Reduced Form ◽  
Serine Esterase ◽  
Hydroxybutyric Acid ◽  
Ph Optimum

A 68-kDa extracellular glycoprotein from Physarum polycephalum that hydrolyses specifically poly(β-L-malic acid) by removing monomers of L-malic acid in an exolytic manner has been purified and characterized. The enzyme was purified 1740-fold from the culture medium by ammonium sulfate precipitation, hydrophobic interaction chromatography on butyl-Toyopearl, and gel permeation chromatography on Superdex 200 to a specific activity of 9.0 μmol∙min−1∙mg−1. The hydrolase was also purified from the cytosol, which contained 1 mg in 43 g cells in contrast to 1 mg extracellular enzyme in 28 L of culture medium. The pH optimum was pH 3.5 as a result of the effect of an acidic side chain on Vmax and the preferred binding of poly(β-L-malate) in the ionized form. Intracellular hydrolase was only marginally active on [14C]poly(β-L-malate) that had been injected into plasmodia. Poly(L-aspartate), poly(L-glutamate), poly(vinyl sulfate), and poly(acrylate) were neither bound nor degraded by the hydrolase. Poly(β-hydroxybutyric acid), which was considered the reduced form of poly(β-L-malate), was not a substrate. The enzyme is neither a metallo- nor a serine-esterase, and is distinct from poly(3-hydroxybutyric acid) depolymerases. It is related to a glucosidase with respect to hydrophobic interaction chromatography, the pH-activity dependence, and its inhibition with mercuribenzoate, N-bromosuccinimide, and D-gluconolactone, but not the use of the substrates.Key words: poly(β-L-malate), polymalatase, Physarum polycephalum, biodegradative polymer.

scholarly journals Construction and Characterization of aMycobacterium tuberculosis Mutant Lacking the Alternate Sigma Factor Gene, sigF

2000 ◽  
Vol 68 (10) ◽  
pp. 5575-5580 ◽  
Author(s):  
Ping Chen ◽  
Rafael E. Ruiz ◽  
Qing Li ◽  
Richard F. Silver ◽  
William R. Bishai
Keyword(s):  
Stationary Phase ◽  
Sigma Factor ◽  
Type Strain ◽  
Wild Type Strain ◽  
Axenic Culture ◽  
Wild Type ◽  
Intracellular Growth ◽  
Factor Gene ◽  
Time To Death

ABSTRACT The alternate RNA polymerase sigma factor gene, sigF, which is expressed in stationary phase and under stress conditions in vitro, has been deleted in the virulent CDC1551 strain ofMycobacterium tuberculosis. The growth rate of the ΔsigF mutant was identical to that of the isogenic wild-type strain in exponential phase, although in stationary phase the mutant achieved a higher density than the wild type. The mutant showed increased susceptibility to rifampin and rifapentine. Additionally, the ΔsigF mutant displayed diminished uptake of chenodeoxycholate, and this effect was reversed by complementation with a wild-type sigF gene. No differences in short-term intracellular growth between mutant and wild-type organisms within human monocytes were observed. Similarly, the organisms did not differ in their susceptibilities to lymphocyte-mediated inhibition of intracellular growth. However, mice infected with the ΔsigF mutant showed a median time to death of 246 days compared with 161 days for wild-type strain-infected animals (P < 0.001). These data indicate that M. tuberculosis sigF is a nonessential alternate sigma factor both in axenic culture and for survival in macrophages in vitro. While the ΔsigF mutant produces a lethal infection of mice, it is less virulent than its wild-type counterpart by time-to-death analysis.

Biological factors affecting enflagellation of Naegleria fowleri

1982 ◽  
Vol 152 (2) ◽  
pp. 803-808
Author(s):  
T W Woodworth ◽  
D T John ◽  
S G Bradley
Keyword(s):  
Population Density ◽  
Stationary Phase ◽  
Culture Medium ◽  
Actinomycin D ◽  
Suitable Model ◽  
Naegleria Fowleri ◽  
Biological Factors ◽  
Factors Affecting ◽  
Nægleria Fowleri ◽  
Amoeboid Cells

Naegleria fowleri is a pathogenic amoeboflagellate that can be evoked to transform from amoebae to flagellates by subculture to nonnutrient buffer. More than half of the amoebae of strains KUL, nN68, and Lovell became enflagellated 300 min after subculture to amoeba-saline, whereas no amoebae of strains NF66, NF69, and HB4 did. N. fowleri nN68 enflagellated best when grown at 32 or 37 degrees C and subcultured to amoeba-saline at 37 or 42 degrees C. Amoebae from the stationary phase of growth enflagellated more readily than did actively growing amoebae. Incubation in expended culture medium from stationary-phase cultures enhanced the capability of growing amoebae to enflagellate after subculture to amoebasaline. Enflagellation was more extensive when the population density in amoebasaline did not exceed 2 x 10(5) amoebae per ml. Cycloheximide at 1 microgram/ml and actinomycin D at 25 micrograms/ml inhibited growth of N. fowleri nN68. Cycloheximide at 0.5 microgram/ml and actinomycin D at 25 micrograms/ml completely prevented enflagellation when added at time zero. Cycloheximide at 0.5 microgram/ml, added 120 to 300 min after initiation of enflagellation, prevented further differentiation and caused existing flagellates to revert to amoeboid cells. Similarly, actinomycin D at 25 micrograms/ml, added 90 to 300 min after initiation of enflagellation, retarded differentiation and caused flagellates to revert. Radiolabeled precursors were incorporated into macromolecules during differentiation in nonnutrient buffer. Enflagellation of N. fowleri is a suitable model for studying regulation of a eucaryotic protist.

scholarly journals Decreased Susceptibilities to Teicoplanin and Vancomycin among Coagulase-Negative Methicillin-Resistant Clinical Isolates of Staphylococci

1998 ◽  
Vol 42 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Krzysztof Sieradzki ◽  
Paolo Villari ◽  
Alexander Tomasz
Keyword(s):  
Stationary Phase ◽  
Staphylococcus Epidermidis ◽  
Culture Medium ◽  
Clinical Isolates ◽  
Prolonged Incubation ◽  
Methicillin Resistant ◽  
Relative Ease ◽  
Selective Enrichment ◽  
Cellular Aggregates ◽  
Tube Dilution

ABSTRACT Of 41 methicillin-resistant coagulase-negative staphylococcal clinical isolates collected during a 5-month period between late 1995 and early 1996, 28 showed tube dilution teicoplanin MICs of 4 to 8 μg/ml which increased to 16 to 32 μg/ml upon prolonged incubation. Cultures of such bacteria were heterogeneous; they contained subpopulations with frequencies of 10−5 to 10−4 that could grow on up to 50 μg of teicoplanin per ml. The same cultures were also heterogeneous with respect to susceptibility to vancomycin; while the MICs for the majority of cells were 2 to 4 μg/ml, subpopulations that could grow on 6 to 12 μg of vancomycin per ml were also present at frequencies of 10−5to 10−7. Selective enrichment of such cultures for the resistant subpopulation occurred with relative ease under laboratory conditions. Heterogeneous phenotypes for teicoplanin (but not for vancomycin) susceptibility were also identified in severalStaphylococcus epidermidis isolates collected during the preantibiotic era. The addition of half the MIC of teicoplanin inhibited autolysis and caused formation of cellular aggregates which disintegrated to individual bacteria in the stationary phase when the titer of teicoplanin in the medium fell to undetectable levels, indicating removal of the antibiotic from the culture medium by the bacteria.

Regulation of expression of the cyanide-insensitive terminal oxidase in Pseudomonas aeruginosa

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1275-1284 ◽  
Author(s):  
Megan Cooper ◽  
Gholam Reza Tavankar ◽  
Huw D. Williams
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Culture Medium ◽  
Homoserine Lactone ◽  
Exponential Phase ◽  
Terminal Oxidase ◽  
Regulation Of Expression ◽  
Potent Inducer ◽  
Protein Levels ◽  
In The Wild

The regulation of the cyanide-insensitive oxidase (CIO) in Pseudomonas aeruginosa, a bacterium that can synthesize HCN, is reported. The expression of a cioA–lacZ transcriptional fusion, CioA protein levels and CIO activity were low in exponential phase but induced about fivefold upon entry into stationary phase. Varying the O2 transfer coefficient from 11·5 h−1 to 87·4 h−1 had no effect on CIO expression and no correlation was observed between CIO induction and the dissolved O2 levels in the growth medium. However, a mutant deleted for the O2-sensitive transcriptional regulator ANR derepressed CIO expression in an O2-sensitive manner, with the highest induction occurring under low-O2 conditions. Therefore, CIO expression can respond to a signal generated by low O2 levels, but this response is normally kept in check by ANR repression. ANR may play an important role in preventing overexpression of the CIO in relation to other terminal oxidases. A component present in spent culture medium was able to induce CIO expression. However, experiments with purified N-butanoyl-l-homoserine lactone or N-(3-oxododecanoyl)homoserine lactone ruled out a role for these quorum-sensing molecules in the control of CIO expression. Cyanide was a potent inducer of the CIO at physiologically relevant concentrations and experiments using spent culture medium from a ΔhcnB mutant, which is unable to synthesize cyanide, showed that cyanide was the inducing factor present in P. aeruginosa spent culture medium. However, the finding that in a ΔhcnB mutant cioA–lacZ expression was induced normally upon entry into stationary phase indicated that cyanide was not the endogenous inducer of the terminal oxidase. The authors suggest that the failure of O2 to have an effect on CIO expression in the wild-type can be explained either by the requirement for an additional, stationary-phase-specific inducing signal or by the loss of an exponential-phase-specific repressing signal.

scholarly journals Effect of iron and silver nanoparticles on coenzyme Q10 production by Gluconobacter japonicus FM10

2020 ◽  
Author(s):  
Foozieh Moghadami ◽  
Ramin Hosseini
Keyword(s):  
Silver Nanoparticles ◽  
Iron Oxide ◽  
Stationary Phase ◽  
Coenzyme Q10 ◽  
Antibacterial Agents ◽  
Production Efficiency ◽  
Culture Medium ◽  
Microbial World ◽  
Beneficial Effects ◽  
First Time

Background and Objectives: Coenzyme Q10 is an anti-aging agent whose demand is increasing progressively. There are various strategies used for increasing coenzyme Q10 production by microorganisms. In this study, for the first time, we investigated the effect of iron oxide and silver nanoparticles on coenzyme Q10 production by Gluconobacter japonicus FM10. Materials and Methods: In the first step, a preliminary experiment was set and carried out to obtain the minimum inhibitory concentrations of the nanoparticles on the strain FM10. Then the sub-MIC concentrations were used to investigate their effect on coenzyme Q10 production in the stationary and exponential phases of the growth, separately. Results: The results showed that coenzyme Q10 production increased in the presence of the iron oxide and silver nanoparticles. The silver nanoparticles induced 1.9 times higher coenzyme Q10 production. The highest level of coenzyme Q10 was induced when the silver nanoparticles were added to the culture medium at the stationary phase. Conclusion: This should be noticed that so far nanoparticles have been considered as antibacterial agents, rather than being considered to cause probable beneficial effects on the induction of useful products in the microbial world. In this regard, their potential for increasing coenzyme Q10 production has received no attention. However, our present results showed that the nanoparticles can be used to increase the production efficiency of coenzyme Q10 in Gluconobacter.

scholarly journals Characterization of Nucleotide Pools as a Function of Physiological State in Escherichia coli

2007 ◽  
Vol 190 (2) ◽  
pp. 718-726 ◽  
Author(s):  
Michael H. Buckstein ◽  
Jian He ◽  
Harvey Rubin
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Growth Curve ◽  
Physiological State ◽  
Extraction Methods ◽  
Modified Method ◽  
New Information ◽  
Deoxynucleoside Triphosphate ◽  
Pool Sizes

ABSTRACT Using a modified method that involves minimal manipulation of cells, we report new information about nucleotide pool sizes and changes throughout the Escherichia coli growth curve. Nucleotide pool sizes are critically dependent on sample manipulation and extraction methods. Centrifugation and even short (2 min) lapses in sample preparation can dramatically affect results. The measured ATP concentration at three different growth rates is at least 3 mM, well above the 0.8 mM needed to saturate the rRNA promoter P1 in vitro. Many of the pools, including ATP, GTP, and UTP, begin to decrease while the cells are still in mid-log growth. After an almost universal drop in nucleotide concentration as the cells transition from logarithmic to stationary phase, there is a “rebound” of certain nucleotides, most notably ATP, after the cells enter stationary phase, followed by a progressive decrease. UTP, in contrast, increases as the cells transition into stationary phase. The higher UTP values might be related to elevated UDP-glucose/galactose, which was found to be at higher concentrations than expected in stationary phase. dTTP is the most abundant deoxynucleoside triphosphate (dNTP) in the cell despite the fact that its precursors, UDP and UTP, are not. All dNTPs decrease through the growth curve but do not have the abrupt drop, as seen with other nucleotides when the cells transition into stationary phase.

Axenic culture of myxamoebae of the myxomycete Echinostelium minutum

1970 ◽  
Vol 48 (3) ◽  
pp. 663-664 ◽  
Author(s):  
Edward F. Haskins
Keyword(s):  
Stationary Phase ◽  
Generation Time ◽  
Axenic Culture ◽  
Serial Passage ◽  
Logarithmic Phase ◽  
First Time ◽  
Axenic Cultivation ◽  
Average Generation Time

Axenic cultivation of the myxomycete Echinostelium minutum De Bary (Echinosteliales) is reported for the first time. After more than a year of serial passage the average generation time of amoebae during the logarithmic phase is 18 h and a stationary phase yield of over 2 × 106 cells/ml is typical.

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