scholarly journals APPARENT TRANS CONTROL OF MURINE βGLUCURONIDASE SYNTHESIS BY A TEMPORAL GENETIC ELEMENT

Genetics ◽  
1978 ◽  
Vol 90 (4) ◽  
pp. 725-734
Author(s):  
Susan A Meredith ◽  
Roger E Ganschow
Keyword(s):  
Structural Gene ◽  
Mode Of Action ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Genetic Element ◽  
F1 Progeny ◽  
Liver And Kidney ◽  
Kinetics Of ◽  
Enzyme Patterns

ABSTRACT A difference in the heat-inactivation kinetics between the β-glucuronidases of C3HeB/FeJ and C57Bl/6J mice was utilized to assess the mode of action of a temporal genetic element in controlling the expression of the β-glucuronidase structural gene Gus. The heat-inactivation kinetics of liver and kidney β-glucuronidase from F1 C3HeB/FeJ x C57Bl/6J animals were intermediate with respect to the parental enzyme patterns, suggesting that equal concentrations of the two allelic products were present in β-glucuronidase tetramers of F1 progeny. β-glucuronidase heteropolymers assembled in vivo under conditions where equal concentrations of the two structural alleles of the enzyme were known to be present also exhibited intermediate heat-inactivation kinetics. These observations are consistent with a trans mode of action of a genetic element that controls the rate of murine β-glucuronidase synthesis.

Effects of Pulsed Electric Fields on Inactivation Kinetics of Listeria innocua

1999 ◽  
Vol 65 (12) ◽  
pp. 5364-5371 ◽  
Author(s):  
Patrick C. Wouters ◽  
Nicole Dutreux ◽  
Jan P. P. M. Smelt ◽  
Huub L. M. Lelieveld
Keyword(s):  
Electric Field ◽  
Physiological State ◽  
Pulse Length ◽  
Listeria Innocua ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Inlet Temperature ◽  
Similar Time ◽  
Process Factors ◽  
Kinetics Of

ABSTRACT The effects of pulsed electric field (PEF) treatment and processing factors on the inactivation kinetics of Listeria innocuaNCTC 11289 were investigated by using a pilot plant PEF unit with a flow rate of 200 liters/h. The electric field strength, pulse length, number of pulses, and inlet temperature were the most significant process factors influencing the inactivation kinetics. Product factors (pH and conductivity) also influenced the inactivation kinetics. In phosphate buffer at pH 4.0 and 0.5 S/m at 40°C, a 3.0-V/μm PEF treatment at an inlet temperature of 40°C resulted in ≥6.3 log inactivation of strain NCTC 11289 at 49.5°C. A synergistic effect between temperature and PEF inactivation was also observed. The inactivation obtained with PEF was compared to the inactivation obtained with heat. We found that heat inactivation was less effective than PEF inactivation under similar time and temperature conditions.L. innocua cells which were incubated for a prolonged time in the stationary phase were more resistant to the PEF treatment, indicating that the physiological state of the microorganism plays a role in inactivation by PEF. Sublethal injury of cells was observed after PEF treatment, and the injury was more severe when the level of treatment was increased. Overall, our results indicate that it may be possible to use PEF in future applications in order to produce safe products.

Dry-heat inactivation of Bacillus subtilis var. niger spores with special reference to spore density

1976 ◽  
Vol 22 (3) ◽  
pp. 359-363 ◽  
Author(s):  
G. Molin ◽  
K. Östlund
Keyword(s):  
Bacillus Subtilis ◽  
Spore Density ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Temperature Range ◽  
Dry Heat ◽  
Z Value ◽  
D Values ◽  
Kinetics Of ◽  
Spore Densities

The dry-heat inactivation kinetics of Bacillus subtilis var. niger (ATCC 9372) spores has been studied in the temperature range of 120–190 °C. The spores were applied to glass plates of a standardized area (3.24 cm2).Spore preparations of five different spore densities were used (8.3 × 104, 7.4 × 105, 7.8 × 106, 6.3 × 107, and 6.6 × 108 spores per sample, respectively). The heat resistance of the spore was dependent on the number of spores per surface unit. Maximum resistance was observed when the concentration was 7.4 × 105 spores per sample. The D-values obtained at 160 °C from these samples were about twice as high as the D-values obtained from samples with a concentration of 6.3 × 107 or 6.6 × 108 spores per sample. The z value was found to be independent of spore density. Thus, for the two concentrations 7.4 × 105 and 6.3 × 107 spores per sample, the z-value was found to be 22 °C and constant over the temperature range investigated.

scholarly journals Pasteurization of milk: The heat inactivation kinetics of milk-borne dairy pathogens under commercial-type conditions of turbulent flow

2012 ◽  
Vol 95 (1) ◽  
pp. 20-35 ◽  
Author(s):  
L.E. Pearce ◽  
B.W. Smythe ◽  
R.A. Crawford ◽  
E. Oakley ◽  
S.C. Hathaway ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Kinetics Of

scholarly journals Dry-Heat Inactivation Kinetics of Naturally Occurring Spore Populations

1970 ◽  
Vol 20 (4) ◽  
pp. 573-578 ◽  
Author(s):  
W. W. Bond ◽  
M. S. Favero ◽  
N. J. Petersen ◽  
J. H. Marshall
Keyword(s):  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Dry Heat ◽  
Naturally Occurring ◽  
Kinetics Of

Dynamic 131I-labelled insulin distribution in rabbits as seen by in-vivo scintigraphic studies

1983 ◽  
Vol 98 (3) ◽  
pp. 331-342 ◽  
Author(s):  
P. Bourgeois ◽  
J. Frühling ◽  
M. Langohr ◽  
J. Coel ◽  
A. Verbist ◽  
...  
Keyword(s):  
Urinary Bladder ◽  
Gamma Camera ◽  
Degradation Products ◽  
Distribution Space ◽  
Glucose Injection ◽  
Liver And Kidney ◽  
Plasma Measurements ◽  
Kinetics Of ◽  
Fold Excess

The kinetics of 131I-labelled insulin distribution in heart, liver, kidneys and urinary bladder of rabbits were studied in vivo by gamma-camera techniques combined with plasma measurements (glucose concentrations and chromatographic separation of insulin and its degradation products). The distribution space of radioiodinated insulin differed from the vascular bed delineated by radioiodinated serum albumin. During a 20-min gamma-camera recording, radioactive degradation products only appeared in the plasma after 10–12 min. Previous administration of a 10 000-fold excess of unlabelled insulin and 5 ml glucose (20%) did not modify the evolution of 131I-labelled insulin cardiac invasion and the subsequent linear decrease of radioactivity. Conversely, wash-out of radioactivity from the liver and kidney was accelerated after preadministration of this excess of unlabelled hormone, binding in these organs accounting for this acceleration. Urinary bladder filling was imaged later than cardiac, hepatic or renal labelling and was only accelerated by polyuria induced by glucose injection, independent of preadministration of unlabelled hormone.

Saccharomyces cerevisiae Thermal Inactivation Kinetics Combined with Ultrasound

1999 ◽  
Vol 62 (10) ◽  
pp. 1215-1217 ◽  
Author(s):  
A. LÓPEZ-MALO ◽  
S. GUERRERO ◽  
S. M. ALZAMORA
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Thermal Inactivation ◽  
Order Reaction ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Thermal Treatments ◽  
Combined Treatments ◽  
First Order ◽  
D Values ◽  
Kinetics Of

Inactivation kinetics of Saccharomyces cerevisiae during thermal treatments at moderate temperatures (45.0, 47.5, 50.0, 52.5, or 55.0°C) combined with application of 20 kHz of ultrasound were evaluated. S. cerevisiae inactivation under the combined effects of heat and ultrasound followed first-order reaction kinetics, with decimal reduction times (D) that varied from 22.3 to 0.8 min. D values in treatments that combined heat and ultrasound were significantly smaller (P < 0.05) than D values obtained for thermal treatments and were more noticeable at temperatures below 50°C. The dependence of the D value on temperature had a significantly (P < 0.05) greater z value for combined treatments. Yeast heat inactivation kinetics revealed decreased thermal resistance caused by ultrasound.

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