Enzyme Activities Through Development: A Synthesis of the Activity and Control of the Various Enzymes as the Embryo Matures

2018 ◽  
pp. 37-74
Author(s):  
Herman Slegers
Keyword(s):  
Enzyme Activities ◽  
And Control

scholarly journals The characteristics and site of inhibition of gluconeogenesis in rat liver cells by bacterial endotoxin. Stimulation of phosphofructokinase-1

1987 ◽  
Vol 242 (3) ◽  
pp. 721-728 ◽  
Author(s):  
R G Knowles ◽  
J P McCabe ◽  
S J Beevers ◽  
C I Pogson
Keyword(s):  
Enzyme Activities ◽  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Liver Cells ◽  
Atp Content ◽  
Rat Liver Cells ◽  
Endogenous Substrates ◽  
And Control ◽  
Control Coefficients ◽  
Stimulation Of

The characteristics and site of inhibition of gluconeogenesis by endotoxin were investigated in liver cells isolated from control and endotoxin-treated rats. Endotoxin treatment was associated with inhibition (40-50%) of gluconeogenesis from lactate plus pyruvate over a range of concentrations of substrate and of oleate and with or without glucose or glucagon. Similar inhibition was observed with asparagine, proline, glutamine, alanine and a substrate mixture, but not with glycerol, glyceraldehyde, dihydroxyacetone or endogenous substrates. There was no change in cellular ATP content or in the rates of ketogenesis or ureogenesis from asparagine, proline or glutamine. Other effects on isotopic fluxes, metabolite contents, enzyme activities and control coefficients were consistent with the suggestion that the effects of endotoxin on gluconeogenesis are exerted at the level of phosphofructokinase-1, and not at phosphoenolpyruvate carboxykinase, pyruvate kinase, pyruvate carboxylase or glucokinase.

scholarly journals Antioxidant SMe1EC2 modulates pentose phosphate pathway and glutathione-dependent enzyme activities in tissues of aged diabetic rats

2017 ◽  
Vol 10 (4) ◽  
pp. 148-154 ◽  
Author(s):  
Nuray Nuriye Ulusu ◽  
Müslüm Gök ◽  
Arzu Ayşe Sayin Şakul ◽  
Nuray Ari ◽  
Milan Stefek ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Enzyme Activities ◽  
Body Weight Loss ◽  
Diabetic Rats ◽  
Pentose Phosphate ◽  
Aged Rats ◽  
Glutathione S Transferase ◽  
Phosphogluconate Dehydrogenase ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
And Control

Abstract The pentose phosphate pathway and glutathione-associated metabolism are the main antioxidant cellular defense systems. This study investigated the effects of the powerful antioxidant SMe1EC2 (2-ethoxycarbonyl-8-methoxy-2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b] indolinium dichloride) on pentose phosphate pathway (PPP) and glutathione-dependent enzyme activities in aged diabetic and aged matched control rats. Diabetes was induced by streptozotocin injection in rats aged 13-15 months. Diabetic and control rats were divided into two subgroups, one untreated and one treated with SMe1EC2 (10 mg/kg/day, orally) for 4 months. SMe1EC2 ameliorated body weight loss, but not hyperglycemia of aged diabetic rats. Diabetes resulted in decreased glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD) and glutathione-S-transferase (GST), yet in unchanged glutathione reductase (GR) in the liver of aged diabetic rats. In the liver of the aged control rats, SMe1EC2 did not affect G6PDH, 6PGDH and GR, but it inhibited GST. SMe1EC2 also failed to affect diabetes-induced decline in 6PGDH, it ameliorated G6PDH but produced further decline in GST in the liver of aged diabetic rats. In the kidney of aged rats, G6PDH and GST were found to be comparable among the groups, but diabetes up-regulated 6PGDH and GR; these alterations were prevented by SMe1EC2. In the heart of aged diabetic rats, while GST remained unchanged, the recorded increase in G6PD, 6PGD, GR was prevented by SMe1EC2. Furthermore, an unchanged GR and remarkable increases in G6PD, 6PGD and GST were found in the lung of the aged diabetic group. These alterations were completely prevented by SMe1EC2. The results suggest that in aged rats SMe1EC2 can ameliorate the response of the kidney, heart and lung but not that of the liver against diabetes-induced glucotoxicity by interfering with the activity of redox network enzymes.

C4 Photosynthesis: Activities of Photosynthetic Enzymes in a Virescent Mutant of Maize Having a Low-Temperature Induced Chloroplast Ribosome Deficiency

1988 ◽  
Vol 15 (3) ◽  
pp. 385 ◽  
Author(s):  
GE Edwards ◽  
CLD Jenkins
Keyword(s):  
Low Temperature ◽  
Enzyme Activities ◽  
Wild Type ◽  
Carboxylase Activity ◽  
Pale Yellow ◽  
Photosynthetic Enzymes ◽  
Normal Green ◽  
Normal Enzyme ◽  
Virescent Mutant ◽  
And Control

A virescent mutant of maize (v16/v16), which has a low temperature induced deficiency in 70S ribosomes, was used to examine whether the enzymes of the C4 pathway and other photosynthetic enzymes are synthesised on chloroplast ribosomes. The mutant and control plants were grown at 20°C and 30°C and the rates of photosynthesis and enzyme activities were compared. There was no photosynthesis in v16/v16 grown at 20°C (pale yellow), while plants grown at 30°C (normal green) had rates equivalent to the wild type and normal enzyme activities. On a leaf area basis, with v16/v16 grown at 20°C, the activity of ribulose 1,5-bisphosphate (RuP2) carboxylase was only 2% that of the wild type grown at this temperature, while the activities of enzymes of the C4 cycle were much higher (as a percentage of the wild type activity: pyruvate,PI dikinase, 22%; NADP-malate dehydrogenase, 35%; NADP-malic enzyme, 47%; and phosphoenolpyruvate (PEP) carboxylase, 68%). In another experiment v16/v16 plants were grown initially at 30°C, then transferred to 20°C. After transfer to 20°C leaves previously formed under 30°C remained green and had normal rates of photosynthesis and enzyme activities, but newly formed leaves were pale yellow (only 11% as much Chl) and had low photosynthesis rates (2% of normal) and RuP2 carboxylase activity (5% of control). However, there was high activity of eight enzymes of the C4 cycle. The low activity of RuP2 carboxylase in the mutant grown at 20°C is consistent with the requirement of 70S ribosomes for its synthesis, while the high activities of enzymes of the C4 cycle, including those which are chloroplastic, suggest their synthesis is nuclear-encoded.

scholarly journals The Characteristics of Antioxidant Activity after Liver Transplantation in Biliary Atresia Patients

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Chih-Jen Chen ◽  
Kuo-Shu Tang ◽  
Ying-Hsien Huang ◽  
Chao-Long Chen ◽  
Li-Tung Huang ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Liver Injury ◽  
Biliary Atresia ◽  
Antioxidant Enzyme ◽  
Enzyme Activities ◽  
Clinical Information ◽  
Antioxidant Enzyme Activities ◽  
High Production ◽  
And Control ◽  
Cholestatic Liver Injury

Purpose. Cholestatic liver injury is associated with a high production of free radicals. The pathogenesis of liver injury in biliary atresia (BA) patients is largely undefined. The goal of the present study was to clarify the oxidative damage and the changes in antioxidant enzyme activities that occur during the development of BA and after liver transplantation (LT).Methods. We enrolled BA patients and control subjects and collected their clinical information. The activities of antioxidant enzymes in BA patients before LT (BA group) and after LT (LT group) were analyzed.Results. The number of mitochondrial DNA copies had increased in the LT group compared with the BA group. Similarly, the activity of glutathione peroxidase had increased in the LT group compared with the BA group. The level of glutathione was higher in the LT group than in the BA group. Malondialdehyde levels were decreased in the LT group compared with the BA group.Conclusions. These data indicate that LT is associated with increased antioxidant enzyme activities and decreased malondialdehyde levels in BA patients. The manipulation of mitochondria-associated antioxidative activity might be an important future management strategy for BA.

Response of teat enzymes of sheep and cattle to stimulation by stilboestrol and oestrogenic subterranean clover

1975 ◽  
Vol 26 (6) ◽  
pp. 1009
Author(s):  
R Smithard ◽  
ER Cole ◽  
JP Kennedy
Keyword(s):  
Enzyme Activity ◽  
Isocitrate Dehydrogenase ◽  
Enzyme Activities ◽  
Dose Range ◽  
Subterranean Clover ◽  
Control Groups ◽  
Short Term ◽  
Positive Linear Relationship ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
And Control

The activities of glucose-6-phosphate dehydrogenase (G-6-PDH), malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICDH) were investigated as indicators of oestrogenic response in sheep and cattle. The activities of the enzymes were higher in teat tissue from wethers and steers injected with stilboestrol dipropionate than in control groups not receiving oestrogen. There was a positive linear relationship between teat enzyme activity and log(dose + 1) in wethers injected with stilboestrol dipropionate over the dose range 0–40 µg/day. G-6-PDH and MDH were used to detect oestrogenic responses in sheep and cattle to feed containing a high proportion of subterranean clover (Trifolium subterraneurn L.) cv. Dwalganup. The differences in mean enzyme activities between treatment and control groups were highly significant. The results indicate that in the short term, teat enzymes of cattle respond to oestrogenic feeds in a manner similar to those of sheep.

Effects of bacterial endotoxin on protecting copper-deficient rats from hyperoxia

1986 ◽  
Vol 61 (3) ◽  
pp. 982-987 ◽  
Author(s):  
T. H. Spence ◽  
S. G. Jenkinson ◽  
K. H. Johnson ◽  
J. F. Collins ◽  
R. A. Lawrence
Keyword(s):  
Superoxide Dismutase ◽  
Enzyme Activities ◽  
Bacterial Endotoxin ◽  
Antioxidant Enzyme Activities ◽  
Low Doses ◽  
Sod Activity ◽  
Hyperoxic Exposure ◽  
And Control ◽  
Phosphate Buffered Saline ◽  
Increased Susceptibility

The administration of very low doses of bacterial endotoxin protects rats during exposure to hyperoxia and is associated with the induction of lung antioxidant enzyme activities. Copper-deficient rats have increased susceptibility to O2 toxicity, which may be related to their decreased lung superoxide dismutase activity (SOD) or decreased plasma ceruloplasmin concentrations. To determine whether endotoxin can protect against hyperoxia in this susceptible model, we exposed copper-deficient and control rats to a fractional inspiratory concentration of O2 greater than 0.95 for 96 h after pretreatment with 500 micrograms/kg of bacterial endotoxin or phosphate-buffered saline (PBS). Mortality in the copper-deficient and control rats given PBS and exposed to O2 for 96 h was 100%. Copper-deficient rats died significantly earlier during the exposure than controls. No mortality occurred in either group treated with endotoxin and hyperoxia despite the decreased activity of copper-dependent enzymes in the copper-deficient rats. Copper-deficient rats treated with endotoxin and exposed to hyperoxia did increase lung Cu-Zn-SOD activity, but activity remained below levels found in air-exposed controls. Mn-SOD activity was found to be induced above air-exposed controls in the copper-deficient rats treated with endotoxin and exposed to hyperoxia. Hyperoxic exposure resulted in a marked increase in plasma ceruloplasmin concentrations in the control rats, but no increases in ceruloplasmin occurred in the copper-deficient animals. Endotoxin protects copper-deficient rats from hyperoxia despite their decreased lung Cu-Zn-SOD activity, and decreased plasma ceruloplasmin.

scholarly journals Acid phosphatase activity in mycorrhizal and non-mycorrhizal Scots pine seedlings in relation to nitrogen and phosphorus nutrition

2014 ◽  
Vol 61 (2) ◽  
pp. 253-264 ◽  
Author(s):  
Barbara Kieliszewska-Rokicka
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Scots Pine ◽  
Enzyme Activities ◽  
Acid Phosphatase Activity ◽  
Nitrogen And Phosphorus ◽  
Enzyme Preparations ◽  
Mycorrhizal Roots ◽  
Axenic Conditions ◽  
And Control

Mycorrhizal and control seedlings of Scots pine (<i>Pinus sylvestris</i> L.) were grown under axenic conditions at various concentrations of nitrogen (0.17 mM, 3.78 mM, 18.92 mM) and phosphorus (0.25 mM, 5.58 mM, 23.5 mM). Enzyme activities of soluble acid phosphatase of excised roots (surface-accessible activity) and of crude enzyme preparations of root tissue (total soluble activity) were analyzed in control and mycorrhizal seedlings. The content of P in pine shoot was also measured. The intermediate supply of nitrogen and phosphorus (N = 3.78 mM, P= 5.58 mM) was optimal for development of ectomycorrhizae. Activity of acid phosphatase was stimulated by higher levels of N in the soil and was higher in mycorrhizal than non-mycorrhizal roots. Pine roots had greater acid phosphatase activity at the reduced than at the higher P concentrations. The presence of mycorrhizae increased the activities of both surface-accessible and total soluble enzyme activities at lower P supply (0.25 mM, 5.58 mM) and decreased it significantly at the highest P concentration (23.5 mM). P content in shoots was higher in mycorrhizal than non-mycorrhizal seedlings.

scholarly journals Photoassimilate Regulation of Sorbitol and Sucrose Metabolism in Peach Fruit

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1116D-1116
Author(s):  
Riccardo Lo Bianco ◽  
Brunella Morandi ◽  
Mark Rieger
Keyword(s):  
Cell Division ◽  
Enzyme Activities ◽  
Developmental Stages ◽  
Sucrose Metabolism ◽  
Peach Fruit ◽  
Relative Growth ◽  
Neutral Invertase ◽  
Photosynthetic Product ◽  
Before And After ◽  
And Control

Along with sucrose, sorbitol represents the major photosynthetic product and the main form of translocated carbon in peach. The objective of the present study was to determine whether in peach fruit, sorbitol and sucrose enzyme activities are source-regulated, and more specifically modulated by sorbitol or sucrose availability. In two separate trials, peach fruit relative growth rate (RGR), enzyme activities, and carbohydrates were measured 1) at cell division stage before and after girdling of the shoot subtending the fruit; and 2) on 14 shoots with different leaf to fruit ratio (L:F) at cell division and cell expansion stages. Fruit RGR and sorbitol dehydrogenase (SDH) activity were significantly reduced by girdling, whereas sucrose synthase (SS), acid invertase (AI), and neutral invertase (NI) where equally active in girdled and control fruits on the fourth day after girdling. All major carbohydrates (sorbitol, sucrose, glucose, fructose and starch) were reduced on the fourth day after girdling. SDH activity was the only enzyme activity proportional to L:F in both fruit developmental stages. Peach fruit incubation in sorbitol for 24 hours also resulted in SDH activities higher than those of fruits incubated in buffer and similar to those of freshly extracted samples. Overall, our data provide some evidence for regulation of sorbitol metabolism, but not sucrose metabolism, by photoassimilate availability in peach fruit. In particular, sorbitol translocated to the fruit may function as a signal for modulating SDH activity.

Enzyme activities in liver and brain fractions from alcoholic and control rats

1981 ◽  
Vol 13 (2) ◽  
pp. 179-186 ◽  
Author(s):  
M.V. Garcia ◽  
M.N. Pérez-González ◽  
J.A. Cabezas
Keyword(s):  
Enzyme Activities ◽  
And Control
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