scholarly journals Effect of glucose and phytohaemagglutinin (PHA) rich Phaseolus vulgaris extract on growth and protein synthesis of pharmaceutically important cyanobacteria Nostoc ellipsosporum NCIM 2786

2013 ◽  
Vol 11 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Srivatsava Anshuman ◽  
Mittal Deepika ◽  
Govindasamy Sharmila ◽  
Chandrasekaran Muthukumaran
1982 ◽  
Vol 242 (3) ◽  
pp. E184-E192 ◽  
Author(s):  
M. P. Hedden ◽  
M. G. Buse

Protein synthesis was measured in rat diaphragms incubated with serum amino acids + 0.35 mM L-[2,6-3H]tyrosine and different energy-yielding substrates. Muscles incubated with 5.5 mM glucose (with or without actinomycin D) synthesized more protein than those incubated with 11 mM pyruvate or 11 mM lactate. Tissue ATP decreased during incubation with lactate, but pyruvate maintained ATP, ADP, and creatine phosphate as well as glucose. Glucose 6-phosphate decreased in muscles incubated in glucose-free media. 14CO2 production from substrates was [1-14C]pyruvate greater than [1-14C]lactate greater than [3,4-14C]glucose. Intracellular lactate/pyruvate was measured to assess cytoplasmic free NADH/NAD+; the effect of different media on these ratios was lactate greater than glucose = lactate + pyruvate greater than pyruvate + glucose greater than pyruvate. Lactate + pyruvate (8.8 + 2.2 mM) supported protein synthesis better than pyruvate and as well as glucose. Adding glucose to pyruvate accelerated protein synthesis and increased NADH/NAD+. Iodoacetate (0.1 mM) inhibited glycolytic NAD reduction and abolished the stimulatory effect of glucose on protein synthesis in the presence of pyruvate. Supplementation of pyruvate media with 1 mM leucine or isoleucine stimulated protein synthesis, but beta-hydroxybutyrate, malate, alpha-ketoisocaproate, and all other amino acids were ineffective. The cytoplasmic redox potential may act as a translational modulator of protein synthesis in skeletal muscle.


1995 ◽  
Vol 132 (5) ◽  
pp. 618-621 ◽  
Author(s):  
Pavel Langer ◽  
Klaudia Gschwendtová

Langer P, Gschwendtová K. Acute changes in biliary excretion of reverse triiodothyronine in rats after insulin-induced hypoglycemia: effect of glucose, verapamil, cycloheximide and actinomycin D. Eur J Endocrinol 1995;132:618–21. ISSN 0804–4643 Biliary excretion of reverse triiodothyronine (rT3) was estimated in rats during hypoglycemia induced by a 10-min infusion of 1 U of insulin (INS) and for the following 5 h. During that period an increase in biliary rT3 was found. This was seen also during the infusion of exogenous glucagon (10 μg in 1.2 ml of saline per 1 h for 5 h) given independently of INS. The infusion of glucose (1 g/kg per 50 min or 2 g/kg per 110 min) following INS infusion delayed the increase in rT3. The increase in rT3 was prevented by actinomycin D (1 mg/kg) when injected before (90 min), but not after (30 min) INS, and also by cycloheximide (2.5 mg/kg) injected immediately before INS. The same dose of cycloheximide also prevented a similar increase of rT3 during the infusion of exogenous glucagon. Verapamil (5 mg/ kg divided into five doses per 4 h) blunted the increase of rT3. These data indicate that following INS injection counter-regulatory hormones may be responsible for the increased production of rT3; this altered metabolic activity apparently is dependent on protein synthesis. Pavel Langer, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlárska 3, 833 06 Bratislava, Slovakia


1981 ◽  
Vol 240 (1) ◽  
pp. E24-E31 ◽  
Author(s):  
V. Grill

Short-term exposure to glucose increases insulin secretion during subsequent stimulation. This priming effect of glucose was further investigated in the perfused rat pancreas. A 5-min pulse of 27.7 mM glucose enhanced the response to a second pulse of the sugar after a 5- or 30-min period of 3.9 mM glucose. With a 10-min pulse of 27.7 mM glucose, the priming effect tended to persist also after a 60-min but not after a 90-min rest period. The priming effects of glucose were also evaluated from enhancement of stimulation 15 min later with 3-isobutyl-l-methylxanthine (IBMX). A 10-min pulse of 8.3 and 27.7, but not 5.6 mM glucose enhanced IBMX-induced insulin secretion. Cycloheximide did not abolish the priming effect of glucose on IBMX-induced insulin secretion. Conclusions are 1) priming is rapidly induced; 2) it persists longer than the time of induction; 3) threshold concentrations of glucose that induce priming are similar to those that initiate insulin secretions; and 4) mechanisms causing priming may not involve protein synthesis.


1981 ◽  
Vol 196 (2) ◽  
pp. 383-390 ◽  
Author(s):  
M J Wakelam ◽  
D G Walker

1. The specificity of the effect of glucose on the induction of glucokinase activity that occurs when hepatocytes freshly isolated from 13-day-old rats are incubated in Medium 199 together with insulin [Wakelam & Walker (1980) FEBS Lett. 111, 115-119] was examined. A pattern that is different from other known effects of glucose is found, and metabolism of this compound is not necessarily to account for this particular effect. 2. The effects of a raised glucose concentration and of insulin on the induction can be separated. The hexose initiates the process in the absence of insulin in a manner that is sensitive to actinomycin D but not to cycloheximide. The subsequent effect of insulin is dependent on the prior effect of glucose or other positive analogue, does not require the presence of glucose and is inhibited by cycloheximide but not by actinomycin D. 3. Induction of glucokinase in vitro in hepatocytes from neonatal animals is inhibited by adrenaline, glucagon and dibutyryl cyclic AMP, but not by vasopressin or angiotensin II. The inhibition by cyclic AMP is on the stage requiring insulin and is comparatively specific, because total protein synthesis is not apparently diminished. 4. The implications of these results are discussed with reference to possible mechanisms of induction and to the situation in vivo.


1960 ◽  
Vol 198 (1) ◽  
pp. 57-59 ◽  
Author(s):  
Ira G. Wool

The effect of various sugars on protein synthesis was studied by measuring the incorporation of C14-histidine into the protein of the isolated diaphragm. In diaphragms from rats fasted 48 hours, histidine-2-C14 incorporation into muscle protein is directly proportional to the glucose concentration in the incubation medium over the range 0–600 mg %. The ability of other sugars to reproduce this effect of glucose on C14-histidine incorporation into diaphragm protein was tested. The following were found to be as effective as glucose: d-mannose; d-xylose; d-ribose; l-sorbose. The following were without effect: d-galactose; d-fructose; 3-methyl glucose; d-arabinose; l-arabinose; l-xylose. Only 2-deoxy-d-glucose was inhibitory. The results indicate that sugars not appreciably utilized by muscle (i.e. d-xylose, d-ribose and l-sorbose) can increase protein synthesis. The findings do not support the theory that the positive influence of carbohydrate on protein metabolism derives solely from its ability to increase the energy available for protein synthesis.


2000 ◽  
Vol 11 (3) ◽  
pp. 833-848 ◽  
Author(s):  
Mark P. Ashe ◽  
Susan K. De Long ◽  
Alan B. Sachs

Glucose performs key functions as a signaling molecule in the yeastSaccharomyces cerevisiae. Glucose depletion is known to regulate gene expression via pathways that lead to derepression of genes at the transcriptional level. In this study, we have investigated the effect of glucose depletion on protein synthesis. We discovered that glucose withdrawal from the growth medium led to a rapid inhibition of protein synthesis and that this effect was readily reversed upon readdition of glucose. Neither the inhibition nor the reactivation of translation required new transcription. This inhibition also did not require activation of the amino acid starvation pathway or inactivation of the TOR kinase pathway. However, mutants in the glucose repression (reg1, glc7,hxk2, and ssn6), hexose transporter induction (snf3 rgt2), and cAMP-dependent protein kinase (tpk1wandtpk2w) pathways were resistant to the inhibitory effects of glucose withdrawal on translation. These findings highlight the intimate connection between the nutrient status of the cell and its translational capacity. They also help to define a new area of posttranscriptional regulation in yeast.


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