Effect of Temperature and Hydrogen-Ion Concentration on the Germination of Spores of Bacillus cereus

Nature ◽  
1957 ◽  
Vol 179 (4573) ◽  
pp. 1301-1302 ◽  
Author(s):  
K. VAS ◽  
G. PROSZT
Keyword(s):  
Bacillus Cereus ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Hydrogen Ion Concentration

THE EFFECT OF TEMPERATURE AND pH ON THE LONGEVITY OF SCHISTOSOMATIUM DOUTHITTI MIRACIDIA

1962 ◽  
Vol 40 (4) ◽  
pp. 615-620 ◽  
Author(s):  
J. Farley
Keyword(s):  
Half Life ◽  
Large Population ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Critical Factors ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Constant Ph

Observations made on the effect of various temperatures and hydrogen ion concentrations on the longevity of Schistosomatium douthitti miracidia showed both to be critical factors. The half-life of the miracidia varied from 1.5 hours at 35 °C to 11 hours at 8 °C, at a constant pH of 7.3. The effect of hydrogen ion concentration was less pronounced, the optimum being pH 7.5. A large population of miracidia from a single liver continued hatching over a 4-hour period with a peak output occurring at half an hour and another at 1 hour after exposure to water. The longevity of the miracidia hatching within the first hour exceeded that of the larvae hatching later.

THE INFLUENCE OF HYDROGEN ION CONCENTRATION WITH PRETREATMENT OF WOOD ON ITS SUBSEQUENT DELIGNIFICATION

1935 ◽  
Vol 13b (5) ◽  
pp. 289-295 ◽  
Author(s):  
A. J. Corey ◽  
O. Maass
Keyword(s):  
Previous Investigation ◽  
Ph Value ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Forced Flow ◽  
Effect Of Temperature ◽  
Hydrogen Ion Concentration ◽  
Temperature Range ◽  
Wood Meal ◽  
Buffer Solutions

The results obtained by the authors in a previous investigation have been checked. The influence of an acid, a salt and a base on the pretreatment of wood at 130 °C. has been determined. It is shown that pretreatment of wood meal decreases the rate of subsequent delignification. Pretreatment was carried out over the temperature range 100° to 140 °C. and the effect of temperature is shown to be very marked. As it was found that the pH of the water after pretreatment decreased, pretreatment was carried out on a chip in which the pH was kept more constant by a forced flow of water through the chip. It is shown that the rate of delignification is increased. Pretreatment was carried out in buffer solutions and it is shown that there is a pH value for which the influence of pretreatment is a minimum. The inferences drawn in connection with sulphite cooking are briefly discussed.

Some Observations on the Dissociation of Hæmocyanin by the Colorimetric Method

1926 ◽  
Vol 3 (3) ◽  
pp. 225-238
Author(s):  
LANCELOT T. HOGBEN
Keyword(s):  
Colorimetric Method ◽  
Hydrogen Ion ◽  
Mass Action ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Heat Of Reaction ◽  
Dissociation Curve ◽  
Hydrogen Ion Concentration ◽  
Mass Action Law ◽  
N Gram

1. By means of the colorimetric method the effect of temperature, hydrogen ion concentration, and salinity upon the dissociation of the haæmocyanin of four species of decapod Crustacea (Maia, Cancer, Palinurus, and Homarus) has been studied. 2. Rise in temperature depresses the dissociation curve continuously between o° and 50° C. Reasons are given in favour of the conclusion that this behaviour is consonant with the applicability of the mass action law. On this understanding the heat of reaction between hæmocyanin and oxygen dissolved in the water phase in the case of Maia is of the order 9500 calories per n gram molecules of oxygen, n being defined as the least number of molecules of oxygen which can enter into the reaction. 3. In the case of all four crustaceans referred to above, the affinity for oxygen diminishes up to a point as the hydrogen ion concentration is increased : on further increasing the hydrogen ion concentration beyond a critical value for which the affinity of the serum for oxygen is minimal, the amount of oxygen taken up at low tensions increases and may surpass the values obtained for serum at normalpH. The similarity of this result with the observations of Rona and Ÿllpo on hæmoglobin is discussed. 4. On concentrating serum with neutral chlorides of the alakali and alkaline earth metals the dissociation curve is made steeper.

Sign in / Sign up

Export Citation Format

Share Document