Growth and respiration of psychrophilic species of the genus Typhula

1971 ◽  
Vol 49 (3) ◽  
pp. 339-347 ◽  
Author(s):  
Rosamund A. Dejardin ◽  
E. W. B. Ward
Keyword(s):  
Oxygen Uptake ◽  
Liquid Culture ◽  
Respiratory Physiology ◽  
Shake Culture ◽  
Optimum Growth ◽  
Snow Mold ◽  
Lag Period ◽  
Pentose Sugars ◽  
Stimulation Of

Growth of three snow mold fungi, Typhula idahoensis Remsb., T. incarnata Lasch ex Fr., and T. trifolii Rostr., was studied in agar and liquid culture. T. idahoensis was grown successfully in shake culture and its respiratory physiology investigated; some of the attendant problems are discussed.All three fungi were highly psychrophilic. The optimum temperatures for growth were 5–10 °C, the maximum about 20 °C and the minimum around −5 °C. Sclerotia were produced at all temperatures which permitted growth, but most abundantly at temperatures above 10 °C.Cultures grown at 10 °C ceased to grow on transfer to temperatures above 20 °C but, within limits, growth resumed on return to 10 °C after a lag period approximately proportional to the degree and duration of the temperature elevation.Oxygen uptake by T. idahoensis was optimal at 20 °C, about 15 °C higher than the optimum growth temperature.Respiratory quotients tended to be higher at 20 °C than at 5 °C and after starvation of the mycelium increased to a greater degree at 20 °C on addition of glucose or acetate. Starvation of the mycelium effectively reduced the level of endogenous reserves.The fungus was able to use, to differing degrees, a variety of hexose and pentose sugars as respiratory substrates. The percentage stimulation of the oxygen uptake by these sugars was greater at 20 °C than at 5 °C.

VITAMIN REQUIREMENTS OF A LOW-TEMPERATURE BASIDIOMYCETE

1962 ◽  
Vol 40 (10) ◽  
pp. 1347-1354 ◽  
Author(s):  
E. W. B. Ward
Keyword(s):  
Low Temperature ◽  
Optimum Concentration ◽  
Western Canada ◽  
Shake Culture ◽  
Optimum Growth ◽  
Mineral Salts ◽  
Snow Mold ◽  
Absolute Requirement ◽  
Vitamin Requirements

The vitamin requirements of an unidentified basidiomycete, the cause of severe snow mold of grasses and legumes in Western Canada, have been determined in shake culture. In a medium composed of D-glucose, L-asparagine, and mineral salts, a mixture of several vitamins supported optimum growth, but an absolute requirement was demonstrated only for thiamine. Pyridoxine stimulated growth in the presence of thiamine. The optimum concentration of thiamine was 50 μg per liter and below this level growth was proportional to concentration. Pyridoxine was effective in the range 50–100 μg per liter in the presence of 50 μg per liter of thiamine. The requirement for thiamine could be satisfied by a mixture of equivalent amounts of thiazole and pyrimidine but not by either alone.

Effect of stimulation of hepatic nerves on hepatic O2 uptake and blood flow

1977 ◽  
Vol 232 (6) ◽  
pp. H652-H656
Author(s):  
W. W. Lautt
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Oxygen Uptake ◽  
Portal Vein ◽  
Hepatic Artery ◽  
Venous Blood ◽  
Neurogenic Vasoconstriction ◽  
Pressure Changes ◽  
Hepatic Nerves ◽  
Stimulation Of

Acute denervation of the liver did not result in changes of oxygen uptake or hemodynamics in the intact liver of the cat. Stimulation of the hepatic nerves resulted in a marked reduction of vascular conductance of the hepatic artery and portal vein (intrahepatic) resulting in almost complete cessation of arterial flow and increased portal blood pressure. The hepatic artery showed a more complete escape from the neurogenic vasoconstriction than did the portal vein. During the stable "escape phase" oxygen delivery was 86% of control, but hepatic extraction of oxygen increased so that oxygen uptake was not altered from control values. The return of oxygen consumption to normal during nerve stimulation suggests that redistribution of hepatic blood flow did not occur. In spite of arterial and portal venous blood pressure changes and changes in gut conductance, oxygen extraction of the gut did not change.

Mechanism of increase of myocardial oxygen uptake produced by catecholamines1

1965 ◽  
Vol 209 (5) ◽  
pp. 913-918 ◽  
Author(s):  
Francis J. Klocke ◽  
Gerard A. Kaiser ◽  
John Ross ◽  
Eugene Braunwald
Keyword(s):  
Cardiac Arrest ◽  
Oxygen Uptake ◽  
Oxidative Metabolism ◽  
Beating Heart ◽  
Canine Heart ◽  
Direct Stimulation ◽  
Before And After ◽  
Heart Preparation ◽  
Hemodynamic Performance ◽  
Stimulation Of

The relative roles of augmented hemodynamic performance and direct stimulation of oxidative metabolism in mediating the increase of myocardial oxygen uptake (MVo2) produced by catecholamines have been examined in an isolated canine heart preparation. The responses of MVo2 to graded doses of isoproterenol, norepinephrine, or epinephrine were determined before and after the induction of cardiac arrest with potassium. Although increases of MVo2 occurred in the arrested state with the larger doses of the amines, they constituted only a small fraction, generally between 5 and 20%, of the increases produced by the same doses of amines when the hearts were beating. It is concluded that while large doses of catecholamines can increase oxidative metabolism of the nonbeating heart by a small amount, the increases of MVo2 produced by catecholamines in the beating heart are due in large part to the hemodynamic alterations which the amines induce.

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.

Transient Stimulation of Oxygen Uptake Induced by Sulfhydryl Reagents inEgeria densaandPotamogeton crispusLeaves

Botanica Acta ◽  
1997 ◽  
Vol 110 (5) ◽  
pp. 388-394 ◽  
Author(s):  
M. Bellando ◽  
S. Sacco ◽  
F. Albergoni ◽  
P. Rocco ◽  
Maria Teresa Marrè
Keyword(s):  
Oxygen Uptake ◽  
Sulfhydryl Reagents ◽  
Stimulation Of

scholarly journals Isolation of chick intestinal nuclei. Effect of vitamin D3 on nuclear metabolism

1969 ◽  
Vol 115 (2) ◽  
pp. 263-268 ◽  
Author(s):  
D. E. M. Lawson ◽  
P. W. Wilson ◽  
D. C. Barker ◽  
E. Kodicek
Keyword(s):  
Vitamin D ◽  
Orotic Acid ◽  
Polymerase Activity ◽  
Vitamin D Status ◽  
Isolated Nuclei ◽  
Whole Cells ◽  
Nuclear Rna ◽  
Rna Polymerase Activity ◽  
Lag Period ◽  
Stimulation Of

1. Chick intestinal nuclei were isolated, with practically no contamination from other organelles and whole cells, by centrifugation through 2·4m-sucrose. 2. The proportions of RNA, DNA and protein of the isolated nuclei were unaffected by the vitamin D status of the birds. The RNA/DNA ratio was 0·15. 3. The incorporation of [5−3H]orotic acid into the rapidly labelled intestinal nuclear RNA, after a 10min. pulse of the orotic acid, was increased in vitamin D-deficient chicks only 10min. after a 125μg. dose of cholecalciferol. 4. There was no stimulation of the DNA-dependent RNA polymerase activity of the isolated nuclei from birds treated with cholecalciferol. 5. The results are discussed in relation to the changes occurring during the lag period, after administration of cholecalciferol and before Ca2+ transport is detected, and the function of the vitamin.

The mass propagation of Lilium in vitro by stimulation of multiple adventitious bulb-scale formation and by shake culture

1983 ◽  
Vol 61 (1) ◽  
pp. 224-228 ◽  
Author(s):  
Shinsaku Takayama ◽  
Masanaru Misawa
Keyword(s):  
Culture Technique ◽  
Scale Formation ◽  
Fresh Medium ◽  
Shake Culture ◽  
Mass Propagation ◽  
Individual Scale ◽  
Stimulation Of

Multiple adventitious bulb scales of Lilium were investigated as a source for bulblet production. Addition of kinetin to the medium markedly increased the number of adventitious bulb scales differentiated from bulblets grown in vitro. The segments with numerous bulb scales were too small to separate into individual bulb scales, but the use of a shake culture technique markedly stimulated their growth. Such bulb scales were severed and each individual scale was transferred to fresh medium without kinetin to induce bulblet formation. The use of multiple adventitious bulb scales grown by shake culture seems to be advantageous for the mass propagation of Lilium bulblets.

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