METABOLIC DEVELOPMENT AND SECONDARY BIOSYNTHESIS IN PENICILLIUM URTICAE

1965 ◽  
Vol 11 (5) ◽  
pp. 765-778 ◽  
Author(s):  
J. D. Bu"Lock ◽  
Diana Hamilton ◽  
M. A. Hulme ◽  
A. J. Powell ◽  
H. M. Smalley ◽  
...  
Keyword(s):  
Phase Transition ◽  
Fatty Acids ◽  
Glucose Oxidation ◽  
Respiratory Activity ◽  
Hexose Monophosphate ◽  
Phenolic Metabolites ◽  
Lower Glucose ◽  
Hexose Monophosphate Pathway ◽  
Acetate Utilization ◽  
Methyl Salicylic Acid

In cultures of Penicillium urticae Bainier, two successive physiological phases are distinguished. In the first, or trophophase, mycelial N, P, RNA, and —SH and the utilization of acetate for synthesis reach maximum values while glucose oxidation, mainly by the hexose monophosphate pathway, is most rapid. In the second, or idiophase, assimilation of N and P is reduced, RNA and —SH levels are lower, glucose is oxidized more slowly and mainly by glycolysis, fatty acids or mannitol accumulate, and special phenolic metabolites derived from 6-methyl-salicylic acid appear. The phase transition occurs sharply, with a minimum of respiratory activity and of acetate utilization; thereafter the pattern of secondary metabolism is established in a stepwise manner. The observations are interpreted in terms of sequential enzyme induction initiated by metabolic dislocation, and the generalized applications of such an hypothesis are considered.

STEADY STATE OXIDATION OF GLUCOSE IN THE HYPOTHYROID DIABETIC RAT: A ROLE FOR THE ADRENAL CORTEX IN GLUCOSE OXIDATION

1963 ◽  
Vol 41 (5) ◽  
pp. 1293-1305
Author(s):  
Dorothy S. Dow ◽  
C. E. Allen
Keyword(s):  
Steady State ◽  
Glucose Oxidation ◽  
Tricarboxylic Acid Cycle ◽  
Critical Factor ◽  
Inhibitory Effect ◽  
Reduced Form ◽  
Diabetic Rat ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Oxidation Of Glucose

A steady state between the specific activities of blood glucose and expired CO2in the hypothyroid diabetic rat was maintained for extended periods of time following a single intraperitoneal injection of glucose-1-C14or glucose-6-C14. Rates of oxidation of the labelled sugars were measured during the steady state.Glucose oxidation by way of glycolysis and the tricarboxylic acid cycle in the hypothyroid diabetic rat paralleled the decrease in expired CO2but glucose oxidation by way of the hexose monophosphate pathway was completely suppressed.It is suggested that the observed inhibitory effect on the hexose monophosphate pathway is due to the maintenance of diphosphopyridine nucleotide in the reduced form as the result of goitrogen inhibition of steroid-catalyzed transhydrogenation.The results suggest that steroid concentration may be a critical factor in regulation of glucose oxidation by way of the hexose monophosphate pathway.

Depressed lipogenesis induced by cold stress

1960 ◽  
Vol 199 (3) ◽  
pp. 449-452 ◽  
Author(s):  
E. J. Masoro
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cold Stress ◽  
Carbohydrate Metabolism ◽  
Liver Cells ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Liver Homogenates ◽  
Fasted Rats ◽  
Low Rate

Liver homogenates were prepared from control, cold-fed and cold-fasted rats. Homogenates from control and cold-fed rats synthesized fatty acids to about the same extent. However, homogenates from cold-fasted rats converted far less acetate-1-C14 to fatty acids than homogenates from control and cold-fed rats. Previous studies showed that lipogenesis is depressed in liver slices from both cold-fed and cold-fasted rats. Probably the fact that lipogenesis is inhibited in the intact liver cells of cold-fed rats is not the result of reduced levels of fatty acid-synthesizing enzymes but is the result of an unfavorable cofactor environment; the evidence indicates that a low rate of TPNH generation via the hexose monophosphate pathway of carbohydrate metabolism causes the reduction in lipogenic activity. The failure in lipogenesis in the liver cells of the cold-fasted rat appears to result from quite a different cause than that of the cold-fed rat. The most likely reason for the low rate of lipogenesis in the liver of cold-fasted rats appears to be the loss of the fatty acid-synthesizing enzymes; however, the possibility that this lipogenic defect is related to the lack of a cofactor—as yet undiscovered— cannot be discounted.

STEADY STATE OXIDATION OF GLUCOSE IN THE HYPOTHYROID DIABETIC RAT: A ROLE FOR THE ADRENAL CORTEX IN GLUCOSE OXIDATION

1963 ◽  
Vol 41 (1) ◽  
pp. 1293-1305
Author(s):  
Dorothy S. Dow ◽  
C. E. Allen
Keyword(s):  
Steady State ◽  
Glucose Oxidation ◽  
Tricarboxylic Acid Cycle ◽  
Critical Factor ◽  
Inhibitory Effect ◽  
Reduced Form ◽  
Diabetic Rat ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Oxidation Of Glucose

A steady state between the specific activities of blood glucose and expired CO2in the hypothyroid diabetic rat was maintained for extended periods of time following a single intraperitoneal injection of glucose-1-C14or glucose-6-C14. Rates of oxidation of the labelled sugars were measured during the steady state.Glucose oxidation by way of glycolysis and the tricarboxylic acid cycle in the hypothyroid diabetic rat paralleled the decrease in expired CO2but glucose oxidation by way of the hexose monophosphate pathway was completely suppressed.It is suggested that the observed inhibitory effect on the hexose monophosphate pathway is due to the maintenance of diphosphopyridine nucleotide in the reduced form as the result of goitrogen inhibition of steroid-catalyzed transhydrogenation.The results suggest that steroid concentration may be a critical factor in regulation of glucose oxidation by way of the hexose monophosphate pathway.

scholarly journals Lipogenesis in rat and guinea-pig isolated epididymal fat-cells

1974 ◽  
Vol 140 (2) ◽  
pp. 211-224 ◽  
Author(s):  
E. David Saggerson
Keyword(s):  
Fatty Acids ◽  
Guinea Pig ◽  
Malate Dehydrogenase ◽  
Isocitrate Dehydrogenase ◽  
Aspartate Aminotransferase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Fat Cells ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Rat Fat Cells

Fat-cells were prepared from rat and guinea-pig epididymal adipose tissue and compared on the basis of the intracellular distributions and activities of enzymes and with respect to their utilization of various U-14C-labelled substrates for lipogenesis. 1. Compared with the rat, guinea-pig extramitochondrial enzyme activities differed in that aconitate hydratase, alanine aminotransferase, ATP–citrate lyase, lactate dehydrogenase, NAD–malate dehydrogenase, NADP–malate dehydrogenase and phosphoenolpyruvate carboxykinase activities were appreciably lower, whereas aspartate aminotransferase, glucose 6-phosphate dehydrogenase, NADP–isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase activities were appreciably higher. Mitochondrial activities of citrate synthase, NADP–isocitrate dehydrogenase and pyruvate carboxylase were appreciably lower, whereas mitochondrial activities of aspartate aminotransferase, glutamate dehydrogenase, NAD–malate dehydrogenase and phosphoenolpyruvate carboxykinase were higher in the guinea pig compared with the rat. 2. In general guinea-pig fat-cells incorporated acetate and lactate into fatty acids more readily than rat fat-cells, whereas rat fat-cells incorporated glucose and pyruvate more readily than guinea-pig fat-cells. 3. Acetate stimulated the incorporation of glucose into fatty acids in rat fat-cells, but had no appreciable effect upon this process in guinea-pig fat-cells. Acetate greatly decreased the incorporation of lactate into fatty acids in cells from both species. 4. Lactate/pyruvate ratios produced by incubation of guinea-pig cells with glucose+insulin were very low compared with those found with rat cells under the same conditions. 5. With glucose (+insulin) or with glucose+acetate (+insulin) as substrates guinea-pig cells produced enough NADPH by the hexose monophosphate pathway to satisfy the NADPH requirements of lipogenesis. In rat fat-cells under the same conditions, hexose monophosphate-pathway NADPH provision was not sufficient to meet the requirements of lipogenesis. 6. These results are discussed, particularly in relationship to the disposition of cytosolic reducing equivalents in the cells.

STEADY-STATE OXIDATION OF GLUCOSE IN HYPERTHYROID AND HYPOTHYROID RATS

1961 ◽  
Vol 39 (6) ◽  
pp. 981-990 ◽  
Author(s):  
Dorothy S. Dow ◽  
C. E. Allen
Keyword(s):  
Steady State ◽  
Blood Glucose ◽  
Glucose Oxidation ◽  
Hexose Monophosphate ◽  
Glucose Load ◽  
Single Intraperitoneal Injection ◽  
Hexose Monophosphate Pathway ◽  
Specific Activities ◽  
Oxidation Of Glucose ◽  
Primary Action

The single intraperitoneal injection of a labelled glucose load has been shown to maintain a steady state with respect to the specific activities of blood glucose and expired CO2for extended periods of time in hyperthyroid and hypothyroid rats. Measurements were made of rates of oxidation of glucose-1-C14and glucose-6-C14during the steady state.The results indicate that glucose oxidation by way of the glycolytic pathway is markedly elevated in the hyperthyroid rat and parallels the increased rate of CO2expiration. Glucose oxidation by way of the hexose monophosphate pathway is completely suppressed. This effect is considered to be due to the preferential maintenance of diphosphopyridine nucleotide in the reduced form.In the hypothyroid rat a decreased rate of glucose oxidation by way of both oxidative pathways parallels the decreased rate of CO2production.The results support the view that the primary action of thyroxine is on oxidative activity. The observed effect on the hexose monophosphate pathway appears to be secondary.

scholarly journals Effects of peroral alanine administration in lactating ewes with decreased availability of glucose

1997 ◽  
Vol 78 (5) ◽  
pp. 805-813 ◽  
Author(s):  
Kjell Holtenius ◽  
Paul Holtenius
Keyword(s):  
Fatty Acids ◽  
Plasma Level ◽  
Free Fatty Acids ◽  
Skeletal Muscles ◽  
Plasma Insulin ◽  
Glucose Oxidation ◽  
Negative Energy ◽  
Crossover Design ◽  
Metabolic Effects ◽  
Significant Elevation

The metabolic effects of a phlorizin-induced drainage of glucose were studied in six lactating ewes with or without peroral alanine drenches in a study of crossover design. Phlorizin gave rise to a small, but significant, elevation of plasma β-hydroxybutyrate. The plasma level of alanine decreased by about 30 % due to the phlorizin injections and alanine was negatively correlated to β-hydroxybutyrate. The plasma level of free fatty acids increased due to phlorizin. Plasma insulin and glucose concentrations were not significantly affected by phlorizin while glucagon level showed a small but significant increase. Peroral alanine drenches to phlorizin-treated ewes gave rise to a transitory elevation of alanine in plasma. The plasma level of free fatty acids was about 40 % lower in phlorizin-treated ewes receiving alanine and β-hydroxybutyrate tended to be lower (P < 0.08). We suggest that β-hydroxybutyrate, apart from its function as an oxidative fuel, might play an important role by limiting glucose oxidation and protein degradation in skeletal muscles during periods of negative energy balance in ruminants. Furthermore, it is suggested that alanine supplementation decreases lipolysis and ketogenesis in lactating ewes.

Fatty acyl chain structure, orientational order, and the lipid phase transition in Acholeplasma laidlawii B membranes. A review of recent 19F nuclear magnetic resonance studies

1984 ◽  
Vol 62 (11) ◽  
pp. 1134-1150 ◽  
Author(s):  
P. M. Macdonald ◽  
B. D. Sykes ◽  
R. N. McElhaney
Keyword(s):  
Phase Transition ◽  
Fatty Acids ◽  
Nuclear Magnetic Resonance ◽  
Acyl Chain ◽  
Orientational Order ◽  
Membrane Lipid ◽  
Fatty Acyl ◽  
Fatty Acyl Chain ◽  
Lipid Phase ◽  
Lipid Phase Transition

The orientational order parameters of monofluoropalmitic acids biosynthetically incorporated into membranes of Acholeplasma laidlawii B in the presence of a large excess of a variety of structurally diverse fatty acids have been determined via 19F nuclear magnetic resonance (19F NMR) spectroscopy. It is demonstrated that these monofluoropalmitic acids are relatively nonperturbing membrane probes based upon physical (differential scanning calorimetry), biochemical (membrane lipid analysis), and biological (growth studies) criteria. 19F NMR is shown to convey the same qualitative and quantitative picture of membrane lipid order provided by 2H-NMR techniques and to be sensitive to the structural characteristics of the membrane fatty acyl chains, as well as to the lipid phase transition. Representatives of each naturally occurring class of fatty acyl chain structures, including straight-chain saturated, methyl-branched, monounsaturated, and alicyclic-ring-substituted fatty acids, were studied and the 19F-NMR order parameters were correlated with the lipid phase transitions (determined calorimetrically). The lipid phase transition was the prime determinant of overall orientational order regardless of fatty acid structure. Effects upon orientational order attributable to specific structural substituents were discernible, but were secondary to the effects of the lipid phase transition. In the gel state, relative overall order was directly proportional to the temperature of the particular lipid phase transition. Not only the overall order, but also the order profile across the membrane was sensitive to the presence of particular structural substituents. In particular, in the gel state specific fatty acyl structures demonstrated a characteristic disordering effect in the membrane order profile. These various observations can be merged to provide a unified picture of the manner in which fatty acyl chain chemistry modulates the physical state of membrane lipids.

scholarly journals Effect of dithiocyano-methane on hexose monophosphate pathway in the respiratory metabolism of Escherichia coli

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanfeng Chen ◽  
Wenjie Ke ◽  
Huabin Qin ◽  
Siwei Chen ◽  
Limei Qin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Control Group ◽  
Respiratory Metabolism ◽  
Hexose Monophosphate ◽  
Hexose Monophosphate Pathway ◽  
Response To Stress ◽  
Glucose Decomposition ◽  
Decomposition Pathway ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract This paper studied the inhibitory effects of dithiocyano-methane (DM) on the glucose decomposition pathway in the respiratory metabolism of Escherichia coli. We investigated the effects of DM on the activities of key enzymes (ATPase and glucose-6-phosphate dehydrogenase, G6PDH), the levels of key product (nicotinamide adenosine denucleotide hydro-phosphoric acid, NADPH), and gene expression in the hexose monophosphate pathway (HMP). The results showed that the minimum inhibitory concentration (MIC) and the minimum bactericide concentration (MBC) of DM against the tested strains were 5.86 mg/L and 11.72 mg/L, respectively. Bacteria exposed to DM at MIC demonstrated an increase in bacterial ATPase and G6PDH activities, NADPH levels, and gene expression in the HMP pathway compared to bacteria in the control group, which could be interpreted as a behavioral response to stress introduced by DM. However, DM at a lethal concentration of 10 × MIC affected glucose decomposition by inhibiting mainly the HMP pathway in E. coli.

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