THE DESTRUCTION OF O,O-DIETHYL-S-2-DIETHYLAMINOETHYL PHOSPHOROTHIOLATE BY LIVER MICROSOMES

Liver homogenates prepared from the rat, rabbit, mouse, and guinea pig possess an enzyme system capable of destroying O,O-diethyl-S-2-diethylaminoethyl phosphorothiolate at the rate of 150 to 200 μg/hr/g of fresh tissue. The homogenates prepared from the pig, dog, cow, and frog destroyed this compound at a rate of 50 to 100 μg/hr/g, but those prepared from man and the cat possessed negligible activity. Rat plasma, brain, kidney, diaphragm, whole gut, and spleen also possessed little or no activity. This enzyme system is located in the microsomes, disruption of which is accompanied by loss of enzymatic activity. The activity is dependent upon oxygen, inorganic phosphate, and diphosphopyridine nucleotide. Inhibitor studies indicate that enzymic SH-groups are necessary. The enzyme has no action on diisopropyl phosphorofluoridate, isosystox, or tetraethyl pyrophosphate, although these compounds are rapidly destroyed by the liver.

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Die Bedeutung der Homogenisationsart und -intensität für die Größe und Konstanz der Sauerstoffaufnahme von Meerschweinchen-Leberhomogenat / The Influence of Mode and Intensity of Homogenization on the Absolute Value and Stability of Oxygen Consumption of Guinea Pig Liver Homogenates

Zeitschrift für Naturforschung C ◽

10.1515/znc-1977-11-1205 ◽

1977 ◽

Vol 32 (11-12) ◽

pp. 908-912 ◽

Cited By ~ 5

Author(s):

H. J. Schmidt ◽

U. Schaum ◽

J. P. Pichotka

Keyword(s):

Oxygen Uptake ◽

Guinea Pig ◽

Measuring Time ◽

Pig Liver ◽

Absolute Value ◽

Modified Method ◽

Simultaneous Measurements ◽

Liver Homogenates ◽

The Absolute ◽

Guinea Pig Liver

Abstract The influence of five different methods of homogenisation (1. The method according to Potter and Elvehjem, 2. A modification of this method called Potter S, 3. The method of Dounce, 4. Homogenisation by hypersonic waves and 5. Coarce-grained homogenisation with the “Mikro-fleischwolf”) on the absolute value and stability of oxygen uptake of guinea pig liver homogenates has been investigated in simultaneous measurements. All homogenates showed a characteristic fall of oxygen uptake during measuring time (3 hours). The modified method according to Potter and Elvehjem called Potter S showed reproducible results without any influence by homogenisation intensity.

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Changes in Antioxidative, Oxidoreductive and Detoxification Enzymes during Development of Aphids and Temperature Increase

Antioxidants ◽

10.3390/antiox10081181 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1181

Author(s):

Roma Durak ◽

Jan Dampc ◽

Monika Kula-Maximenko ◽

Mateusz Mołoń ◽

Tomasz Durak

Keyword(s):

Antioxidant Enzymes ◽

Enzymatic Activity ◽

Antioxidant Enzyme ◽

Temperature Increase ◽

Enzyme System ◽

Life Cycles ◽

Detoxification Enzymes ◽

Strong Positive Correlation ◽

Positive Correlation ◽

Antioxidant Enzyme System

Temperature, being the main factor that has an influence on insects, causes changes in their development, reproduction, winter survival, life cycles, migration timing, and population dynamics. The effects of stress caused by a temperature increase on insects may depend on many factors, such as the frequency, amplitude, duration of the stress, sex, or the developmental stage of the insect. The aim of the study was to determine the differences in the enzymatic activity of nymphs and adult aphids Aphis pomi, Macrosiphum rosae and Cinara cupressi, and changes in their response to a temperature increase from 20 to 28 °C. The activity of enzymatic markers (superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), β-glucosidase, polyphenol oxidase (PPO) and peroxidase (POD)) in aphid tissues was analysed for three constant temperatures. The results of our research showed that the enzymatic activity of aphids (measured as the activity of antioxidant, detoxifying and oxidoreductive enzymes) was mainly determined by the type of morph. We observed a strong positive correlation between the activity of the detoxifying and oxidoreductive enzymes and aphids’ development, and a negative correlation between the activity of the antioxidant enzymes and aphids’ development. Moreover, the study showed that an increase in temperature caused changes in enzyme activity (especially SOD, CAT and β-glucosidase), which was highest at 28 °C, in both nymphs and adults. Additionally, a strong positive correlation between metabolic activity (heat flow measured by microcalorimeter) and longevity was observed, which confirmed the relationship between these characteristics of aphids. The antioxidant enzyme system is more efficient in aphid nymphs, and during aphid development the activity of antioxidant enzymes decreases. The antioxidant enzyme system in aphids appears to deliver effective protection for nymphs and adults under stressful conditions, such as high temperatures.

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COMPARISONS OF THE OXIDATION OF C19-HYDROXYSTEROIDS BY GUINEA PIG LIVER HOMOGENATES

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)64973-7 ◽

1957 ◽

Vol 224 (2) ◽

pp. 811-818

Author(s):

Charles D. Kochakian ◽

Betty R. Carroll ◽

Barbara Uhri

Keyword(s):

Guinea Pig ◽

Pig Liver ◽

Liver Homogenates ◽

Guinea Pig Liver

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Stimulation of Carbon Tetrachloride Metabolism by Alcohols in Guinea-Pig Liver Microsomes

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)48584-3 ◽

2000 ◽

Vol 82 ◽

pp. 280

Author(s):

Kohyu Fujii

Keyword(s):

Carbon Tetrachloride ◽

Guinea Pig ◽

Liver Microsomes ◽

Pig Liver ◽

Guinea Pig Liver Microsomes ◽

Guinea Pig Liver ◽

Stimulation Of

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Glucocorticoid effects on respiration and metabolism by rat liver homogenates

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1962.202.2.343 ◽

1962 ◽

Vol 202 (2) ◽

pp. 343-346 ◽

Cited By ~ 5

Author(s):

Dennis D. Goetsch ◽

L. E. McDonald

Keyword(s):

Lactic Acid ◽

Oxygen Uptake ◽

Rat Liver ◽

Inorganic Phosphate ◽

Chronic Administration ◽

Glucocorticoid Treatment ◽

Carbohydrate Utilization ◽

Protein Levels ◽

Liver Homogenates ◽

And Control

The effects of glucocorticoid administration on oxygen uptake, glucose and glycogen disappearance, lactic acid formation, and inorganic phosphate and protein levels in rat liver homogenates have been studied. A single injection of hydrocortisone, prednisolone, or 9 α-fluoroprednisolone 5 hr before sacrifice resulted in a highly significant increase in oxygen uptake by rat liver homogenates, whereas chronic administration of prednisolone daily for 7 days caused a marked inhibition in homogenate respiration. Glycolytic rate did not appear to be affected by single injections since endogenous carbohydrate utilization was similar in liver homogenates prepared from control and treated animals. Incubation of liver homogenates under aerobic conditions disclosed that inorganic phosphate levels were decreased in homogenates from corticoid-treated rats, whereas these levels were similar in treated and control liver homogenates incubated under nitrogen. Under anaerobic conditions, liver homogenates from treated rats accumulated lactic acid more rapidly than untreated liver homogenates. Glucocorticoid treatment did not appear to affect protein disappearance since no differences between protein levels in treated and untreated rat liver homogenates were detected following incubation.

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