REGULATION OF INDUCED CELLULASE SYNTHESIS IN PYRENOCHAETA TERRESTRIS GORENZ ET AL. BY UTILIZABLE CARBON COMPOUNDS

1966 ◽  
Vol 12 (2) ◽  
pp. 209-220 ◽  
Author(s):  
J. C. Horton ◽  
N. T. Keen
Keyword(s):  
Substrate Concentration ◽  
Liquid Culture ◽  
Threshold Rate ◽  
Carbon Compounds ◽  
Pyrenochaeta Terrestris ◽  
Low Threshold ◽  
Related Compounds

Cellulase (Cx) synthesis was inducible by Pyrenochaeta terrestris in liquid culture. Cellulase activities on various types and amounts of cellulose reached specific maximum plateaus which were maintained indefinitely. These plateaus were reestablished when the enzyme was diluted at each substrate concentration. The maximum levels appeared related to rates of cellulolysis. Above a low threshold rate of hydrolysate liberation, maximum Cx levels are ordered inversely to cellulolytic rates. Supplementing the inducer cellulose with glucose or related compounds above 5 × 10−4 M repressed synthesis nearly to the basal level. The evidence lends credence to a hypothesis that Cx synthesis by P. terrestris is regulated by an inducer:repressor mechanism.

Production of deoxynivalenol and related compounds in liquid culture by Fusarium graminearum

1983 ◽  
Vol 29 (9) ◽  
pp. 1171-1178 ◽  
Author(s):  
J. D. Miller ◽  
A. Taylor ◽  
R. Greenhalgh
Keyword(s):  
Fusarium Graminearum ◽  
Fungal Biomass ◽  
Organic Nitrogen ◽  
Time Course ◽  
Liquid Culture ◽  
Culture Method ◽  
Medium Ph ◽  
Organic Nitrogen Source ◽  
Major Factors ◽  
Related Compounds

A liquid culture method for the production of deoxynivalenol and related compounds by Fusarium graminearum was developed. Major factors which stimulate the biosynthesis of these compounds include reduced oxygen levels, depletion of carbohydrate in the medium, pH, and possibly a low concentration of an organic nitrogen source. Isolates of F. graminearum were tested for the yields of four trichothecene mycotoxins and zearalenone in this system. The time course of acetyl deoxynivalenol, deoxynivalenol, and zearalenone in the fermentation was measured over a 21-day period against pH, glucose concentration, protein, fungal biomass, and ergosterol. A new ester of deoxynivalenol, 15-acetyl-deoxynivalenol, is reported from North American isolates of F. graminearum.

scholarly journals Comparative Toxicities of Mimosine and Some Chemically Related Compounds to Mouse Bone Marrow Cells in Liquid Culture

1978 ◽  
Vol 31 (2) ◽  
pp. 115 ◽  
Author(s):  
MP Hegarty ◽  
CP Lee ◽  
GS Christie ◽  
FG De Munk ◽  
RD Court
Keyword(s):  
Bone Marrow ◽  
Amino Acid ◽  
Liquid Culture ◽  
Bone Marrow Cells ◽  
Potent Inhibitor ◽  
Mouse Bone Marrow ◽  
Inhibitory Mechanism ◽  
Related Compounds ◽  
Mouse Bone Marrow Cells ◽  
Marrow Cells

Mimosine, a plant amino acid which is toxic in mammals, was shown to be a potent inhibitor of incorporation of [3H)thymidine in mouse bone marrow cells in liquid culture (> 70 % inhibition at a concentration of 2 x 10-4 M). To determine the parts of the molecule responsible for the inhibitory mechanism the effects of 13 chemically related compounds were examined in this system.

Gasphasen-Reaktionen, 71 PE-Spektren und Pyrolysen stickstoffreicher Kohlenstoff-Verbindungen: CN4, C2N4, C2H2N4, C4H6N4 und C5H4N4 Gasphase Reactions, 72 PE Spectra and Pyrolyses of Nitrogen-Rich Carbon Compounds: CN4, C2N4, C2H2N4, C4H6N4 and C5H4N4

1990 ◽  
Vol 45 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Hans Bock ◽  
Ralph Dammel
Keyword(s):  
Real Time ◽  
Radical Cation ◽  
Flow System ◽  
Low Pressure ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Carbon Compounds ◽  
Related Compounds

AbstractThe PE spectra of the nitrogen-rich title compounds cyanogen azide NC-N3, azodicarbonitrileNC - N = N - CN, azidoacetonitrile NC - H2C - N3, tetrazolo[1,5-a]pyridine (H4C5N)(N )3 andtrimethylenetetrazole (H2C)3(CN4) are presented and assigned by radical cation state comparisonwith related compounds or by Koopmans’ correlation with MNDO eigenvalues. In a low pressureflow system the compounds decompose at higher temperatures, with elimination of the thermodynamicallyfavorable N2 molecule. PE-spectroscopic real-time analysis reveals as further products:NC - N3 → C∞, NC - N = N - CN → NC - CN , NC - H2C - N3 → 2HCN (+ traces NC - HC = NH?)and (H2C)3(CN4) → H2C = N - CN + H2C = CH2. For tetrazolo[1,5-a]pyridine, a preceding ringopening to the corresponding 2-azidopyridine is observed.

STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES. XXXV. POLYSACCHARIDE SYNTHESIS BY THE ACTION OF ACETOBACTER XYLINUS ON CARBOHYDRATES AND RELATED COMPOUNDS

1931 ◽  
Vol 4 (4) ◽  
pp. 372-388 ◽  
Author(s):  
H. L. A. Tarr ◽  
Harold Hibbert
Keyword(s):  
High Yield ◽  
Experimental Conditions ◽  
Polysaccharide Synthesis ◽  
Carbon Compounds ◽  
Bacterial Action ◽  
Effective Synthesis ◽  
Surface Polysaccharide ◽  
Related Compounds ◽  
Nutrient Solutions ◽  
Primary Oxidation

The action of Acetobacter xylinus, when cultivated in nutrient solutions containing certain carbohydrates or polyhydric alcohols, in forming surface polysaccharide membranes has been confirmed. The nutrient substrate necessary for the effective synthesis of nitrogen and ash-free polysaccharides from such carbon compounds has been carefully determined, and the necessity for the presence of a small amount of ethyl alcohol definitely proved. This type of synthesis appears to be specific for this organism, in that only the hexoses, their anhydrides and compounds which presumably yield hexoses as a result of the bacterial action, give rise to polysaccharide formation. When the carbon compound used is not a free hexose, nor one apparently capable of conversion into a hexose, as in the case of pentoses such as arabinose and xylose, glycols, polyglycols and erythritol, no membrane formation takes place. On the other hand mannitol, which is known to undergo oxidation with the formation of fructose under the experimental conditions, gives rise to a high yield of a synthetic polysaccharide. Glycerol behaves similarly, due presumably to a primary oxidation to dihydroxy acetone and conversion of this to fructose, the latter then yielding the polysaccharide membrane. The introduction of a methyl group into glycerol and glucose, with the formation of α-methyl glycerol and α-methyl glucoside, respectively, inhibits polysaccharide formation. The product obtained from glucose was found to be very closely related to cellulose, if not identical with it (13). Galactose is much less reactive than glucose, while mannose appears to be relatively inactive with the strain of A. xylinus employed. The highest yield of the polysaccharide was obtained from fructose, a result presumably connected with the recognized fact that this bacterium forms little or no acid from this sugar.

INDUCTION AND REPRESSION OF ENDOPOLYGALACTURONASE SYNTHESIS BY PYRENOCHAETA TERRESTRIS

1966 ◽  
Vol 12 (3) ◽  
pp. 443-453 ◽  
Author(s):  
N. T. Keen ◽  
J. C. Horton
Keyword(s):  
Galacturonic Acid ◽  
Liquid Culture ◽  
Mucic Acid ◽  
Tartronic Acid ◽  
Pyrenochaeta Terrestris ◽  
Fungus Growth

Endopolygalacturonase (endo-PG) synthesis was inducible in standing and replacement liquid culture by Pyrenochaeta terrestris. Inducers were galacturonic acid, its polymers (pectin and polypectate), and structural relatives (mucic acid, tartronic acid, and dulcitol). On pectin, fungus growth and endo-PG synthesis were proportional to initial pectin concentration.Synthesis of endo-PG on pectin was stimulated by hexose supplements at 0.005 M and repressed by supplements at 0.05 M and above. Thus, repression of induced endo-PG synthesis was not dominant at low supplement concentrations as was found for induced cellulase synthesis by the same organism. This suggests that the production of endo-PG by the parasite during pathogenesis is less repressed by host sugars than is cellulase synthesis.

A theory of contamination in electron microscopes by surface diffusion

1978 ◽  
Vol 36 (1) ◽  
pp. 116-117
Author(s):  
J.T. Fourie
Keyword(s):  
Electron Beam ◽  
Surface Diffusion ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Physical Parameters ◽  
Carbon Compounds ◽  
Hydrocarbon Molecules ◽  
Electron Microscopes ◽  
Primary Electrons ◽  
Long Chain

Contamination in electron microscopes can be a serious problem in STEM or in situations where a number of high resolution micrographs are required of the same area in TEM. In modern instruments the environment around the specimen can be made free of the hydrocarbon molecules, which are responsible for contamination, by means of either ultra-high vacuum or cryo-pumping techniques. However, these techniques are not effective against hydrocarbon molecules adsorbed on the specimen surface before or during its introduction into the microscope. The present paper is concerned with a theory of how certain physical parameters can influence the surface diffusion of these adsorbed molecules into the electron beam where they are deposited in the form of long chain carbon compounds by interaction with the primary electrons.

Low threshold open science

2014 ◽  
Author(s):  
Chris H. J. Hartgerink
Keyword(s):  
Open Science ◽  
Low Threshold

Zebrafish models for hallucinogenic-related compounds

2013 ◽  
Author(s):  
A. V. Kalueff ◽  
A. M. Stewart ◽  
V. Gjeloshi ◽  
D. Kondaveeti ◽  
N. Neelkantan ◽  
...  
Keyword(s):  
Related Compounds
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