A colorimetric micro-method for the determination of glucose

Isonitrogenous low-carbohydrate diet elicits specific changes in metabolic gene expression in the skeletal muscle of exercise-trained mice

With the renewed interest in low-carbohydrate diets (LCDs) in the sports field, a few animal studies have investigated their potential. However, most rodent studies have used an LCD containing low protein, which does not recapitulate a human LCD, and the muscle-specific adaptation in response to an LCD remains unclear. Therefore, we investigated the effects of two types of LCDs, both containing the same proportion of protein as a regular diet (isonitrogenous LCD; INLCD), on body composition, exercise performance, and metabolic fuel selection at the genetic level in the skeletal muscles of exercise-trained mice. Three groups of mice (n = 8 in each group), one fed a regular AIN-93G diet served as the control, and the others fed either of the two INLCDs containing 20% protein and 10% carbohydrate (INLCD-10%) or 20% protein and 1% carbohydrate (INLCD-1%) had a regular exercise load (5 times/week) for 12 weeks. Body weight and muscle mass did not decrease in either of the INLCD-fed groups, and the muscle glycogen levels and endurance capacity did not differ among the three groups. Only in the mice fed INLCD-1% did the plasma ketone concentration significantly increase, and gene expression related to glucose utilization significantly declined in the muscles. Both INLCD-1% and INLCD-10% consumption increased gene expression related to lipid utilization. These results suggest that, although INLCD treatment did not affect endurance capacity, it helped maintain muscle mass and glycogen content regardless of the glucose intake restrictions in trained mice. Moreover, an INLCD containing a low carbohydrate content might present an advantage by increasing lipid oxidation without ketosis and suppressing muscle glucose utilization.

Improved methane production from corn straw using anaerobically digested sludge pre-augmented by nanobubble water

Nanobubble water (NBW) has been proven to efficiently improve methane production from organic solid wastes. However, the increase in reactor volume due to addition of NBW hinders its practical applications. In this study, anaerobically digested sludge was first pre-augmented by N₂-NBW and O₂-NBW using corn straw as sole substrate for methane production with electron transfer activity being monitored. 20%, 33% and 38% of cellulose and 29%, 35% and 35% of hemicellulose were reduced respectively from the control, N₂-NBW and O₂-NBW pre-augmented sludge reactors. N₂-NBW and O₂-NBW pre-augmented sludge reactors achieved methane yields of 127 and 142 mL/g-VS, about 10% and 22% higher than that from the control. Results show that use of NBW pre-augmented anaerobically digested sludge as inoculum can remarkably enhance methane yield from corn straw, providing a novel concept for NBW-based anaerobic digestion system with no increase of reactor volume and construction cost in practice.

Enhanced hydrolysis and acidification of cellulose at high loading for methane production via anaerobic digestion supplemented with high mobility nanobubble water

In this study, CH₄ production from anaerobic digestion (AD) of refractory cellulose was investigated at a high loading of 3.5 (VS_cellulose/VS_inoculum) under nanobubble water (NBW) addition. A longer proton spin-spin relaxation time (2611-2906 ms) of NBW during 35 days' storage reflected its high mobility and diffusion of water molecules. Higher volatile fatty acids were yielded at the hydrolysis-acidification stage under NBW addition. Methanogenesis tests showed that Air-NBW and CO₂-NBW supplementation accelerated the utilization of crystalline cellulose, achieving methane yields of 264 and 246 mL CH₄/g-VS_reduced, increasing by 18% and 10% compared to deionized water addition (the control), respectively. In addition, under NBW addition the cellulose crystallinity reduction was enhanced by 14-20% with microbial community being enriched with hydrolytic and methanogenic bacteria. Results from this work suggest that NBW environment with no chemical addition and relatively low energy consumption is advantageous for enhanced AD process of cellulosic biomass.

Enhanced hydrogen production from anaerobic fermentation of rice straw pretreated by hydrothermal technology

This study tested the effect of hydrothermal treatment (HTT) at different peak temperatures (150 °C and 210 °C, i.e. HTT150 and HTT210, respectively) and holding time (0-30 min) on the solubilization of rice straw at total solids (TS) of 20% and then subsequent H2 production from resultant substrates. No obvious degradation was detected in lignin content under all tested HTT conditions which did open up the surface structure and have efficient solubilization effect on rice straw. Soluble carbohydrates produced from straw particles during HTT210 was found to have strongly (r=0.9987) positive correlation with the subsequent H2 yield. The maximum soluble carbohydrates, 80 mg per gram of volatile solids (VS) was achieved under HTT210 and 0 min of holding condition, correspondingly yielding the highest hydrogen production (28 ml/g-VS), about 93-fold higher than the control. Results suggest that holding time is crucial for HTT pretreatment when taking subsequent H2 production into consideration.

Seasonal variation in the biochemical composition of Mytilicola intestinalis

The biochemical constitution of the copepod parasite Mytilicola intestinalis was determined and seasonal changes were detected which, in general, could be correlated with the life-history of the parasite.

Biochemical constituents have been discussed in relation to those in other endoparasites and free-living crustaceans. It was concluded that carbohydrates and lipids both formed important stores of energy in M. intestinalis. Protein levels were reduced compared with those in free-living forms.

This work forms part of a Ph.D. thesis in the University of London. It was completed during the tenure of a Research Assistantship at The Polytechnic, Regent Street, London W. 1.

Biochemical and enzymatic changes after black scorpion Heterometrus fastigiousus Couzijn envenomation in experimental albino mice

The toxic effects of Asian black scorpion Heterometrus fastigiousus (Family, Scorpionidae) venom were determined in albino mice (NIH strain). Venom was isolated and fractioned by Sepharose CL-6B column chromatography. The toxicity of fractioned venom was determined in albino mice by subcutaneous envenomation. The LD(50) of venom was found to be 15 mg kg(-1) body weight and range of molecular weight of venom proteins responsible for toxicity was found from 9.5-63 kDs. The effects of fractioned venom on different biochemical and enzymatic parameters in blood serum and gastrocnemius muscle tissue of albino mice were determined after experimental envenomation. An increase in serum levels of glucose, free amino acids, uric acid, pyruvic acid and total protein was observed while a decrease in the cholesterol level in serum was observed after 4 h of envenomation. Increase in alkaline phosphatase (ALP), acid phosphatase (ACP), lactic dehydrogenase (LDH) and glutamate-pyruvate transaminase (GPT) enzyme activity in serum was observed. Glycogen content in liver, atria, ventricle, rectus abdominus and gastrocnemius muscle was decreased after experimental envenomation. Activity of ALP, ACP, LDH, GPT, AChE and Na+K+ATPase enzymes in gastrocnemius muscle tissue of envenomed albino mice was studied. Inhibition in ALP, AChE and Na+K+ATPase enzyme activity and increase in ACP, LDH and GPT enzyme activity was observed in gastrocnemius muscle after scorpion envenomation. In vitro studies with AChE and Na+K+ATPase enzymes indicated that enzymatic activity of AChE was inhibited competitively by fractioned venom in gastrocnemius muscle.

Effect of prostaglandin F2alpha on gonadal carbohydrate metabolism of silkworm, Bombyx mori L

Effect of prostaglandin F2alpha (PGF2alpha) on carbohydrate accumulation in gonads of the multivoltine silkworm (hybrid: Xinhang x Keming) has been studied by means of topical application to larvae of the silkworm. Increased weights of larvae and reproduction organs, as well as carbohydrate metabolism in gonads of the silkworm, Bombyx mori L. was found after treatment with prostaglandin F2alpha. The increase in weight (larvae 21.9%, testis 28.9%, and ovary 33.3%) was associated with increases in the biomolecules (20-30%) and LDH and aldolase activity (18-25%). The results suggest that the accumulation of carbohydrates denotes a higher extent of utility of the energy sources in function of the testes and ovaries, and the routine application of prostaglandin F2alpha would be helpful in improving the reproductivity and egg quality of the silkworm.

Effect of bacterial endotoxin on metabolism. II Protein-carbohydrate balance following cortisone. Inhibition of intestinal absorption and adrenal response to ACTH

Urinary nitrogen excretion over a 17 hour period without food and water was determined for mice poisoned with endotoxin and for control mice with and without the subcutaneous injection of 5 mg. cortisone acetate. Endotoxin did not alter the quantity of nitrogen excreted, compared with that of control mice, but in both groups of animals cortisone increased urinary nitrogen by the same amount. A balance between the quantity of protein catabolized (as estimated by increased urinary nitrogen excretion) and the total carbohydrate stored as a result of cortisone administration was found in fasted and in fed mice but not in endotoxin-poisoned mice. Endotoxin inhibited the motility of the gastrointestinal tract and blocked the absorption of food. Injections of ACTH in normal mice increased protein degradation and carbohydrate synthesis. In endotoxin-poisoned animals, ACTH failed to alter urinary nitrogen excretion and carbohydrate reserves. ACTH increased susceptibility to endotoxin. The number of heat-killed cells of S. typhimurium required to block the increase in urinary nitrogen caused by an injection of ACTH was found to be 10⁸. A partial block was found with 5 x 10⁷ cells but not with 10⁵ cells. Mice infected with S. typhimurium excreted less than the normal amount of urinary nitrogen in response to ACTH 6 to 23 hours postinfection while normal amounts of nitrogen were eliminated 54 to 71 hours postinfection. The number of viable cells in the mice during the earlier period was less than the number of dead cells required to alter the nitrogen output, while the reverse was true during the later period.

Effects of bacterial endotoxin on metabolism. I. Carbohydrate depletion and the protective role of cortisone

Mice of different strains were protected against the lethal effect of bacterial endotoxin by concurrent injections of cortisone. Either inadequate amounts of cortisone or excessive quantities of endotoxin voided the protection. Analyses of blood sugar, liver glycogen, muscle glycogen, and total body carbohydrate in the skinned eviscerated carcass were carried out on different strains of mice given endotoxin and/or cortisone. Poisoned animals were virtually depleted of all carbohydrate while mice given cortisone alone had concentrations of carbohydrate from three to four times that of normal mice. Mice given a lethal amount of endotoxin and a protective dose of cortisone had two to three times as much carbohydrate as animals injected with the same amount of endotoxin alone but significantly less than that found in normal mice. Dibenzyline failed to alter the lethal effect of endotoxin and to reduce the carbohydrate loss that accompanied endotoxin administration. Endotoxin, at the dosage level employed, lowered the temperature of mice 2°–3°C. during the first hour or two postinjection and the temperature remained essentially unaltered during the next 4 to 5 hours. Loss in body carbohydrate in endotoxin-poisoned mice cannot be explained, therefore, as the result of an elevated metabolic rate accompanying hyperthermia. Endotoxin prevented the conversion of injected glucose into liver glycogen but not into muscle glycogen. Mouse liver mitochondria, in the presence of endotoxin, released from ATP approximately the same amount of inorganic phosphate as that released in the presence of dinitrophenol.

Age-related changes in glucose uptake of cerebral hemisphere slices of male garden lizards in response to starvation stress

In the male garden lizard, the glucose uptake of cerebral hemisphere slices did not change during maturation (young to middle-aged) but declined during ageing (middle-aged to old). Short-term starvation (3 days) did not cause a significant change in glucose uptake of cerebral hemisphere of young lizards but led to an increase in the parameter in both the middle-aged and old.

Influence of human urinary erythropoietin and L-thyroxine on blood morphology and energy reserves in two tropical species of fed and starved teleosts

Erythropoietic responses of fed and starved species of teleosts, viz., Clarias batrachus and Heteropneustes fossilis, to human urinary erythropoietin and thyroxine have been examined. The effects of these hormones on energy reserves have also been evaluated. Twenty-four C. batrachus were divided into two groups: half were fed regularly; the remaining fish were starved 20 days. On the 21st day each group was further divided into three subgroups of four each and received either saline, thyroxine (8 micrograms), or erythropoietin (6 IU) over 4 consecutive days. The experimental protocol was identical for H. fossilis; however, for H. fossilis two identical studies were conducted approximately 1 year apart. A decline in the rate of erythropoiesis and a stimulatory response to human urinary erythropoietin followed starvation in both species of teleosts. In addition, erythropoietin had a pronounced effect on hepatic glycogenesis of fed H. fossilis and stimulated erythropoiesis in the fed teleosts of both species. Prolonged starvation drastically depleted hepatic glycogen in C. batrachus. In contrast, it had no effect on hepatic glycogen in H. fossilis and on muscle glycogen and protein in both species. In general, while both species could respond to erythropoietin and withstand prolonged starvation, H. fossilis alone exhibited remarkable tolerance to fasting.

Effect of methylene blue and cobaltous chloride on the alloxan-induced changes in collagen characteristics in the skin of garden lizard Calotes versicolor

In the present study the effect of two chemicals such as methylene blue and CoCl2 on the accelerated ageing of collagen in alloxan-diabetic lizards has been tested. Both methylene blue and CoCl2 have been found to accelerate the ageing of collagen in normal lizards. While methylene blue enhanced the effects of alloxan in alloxanized lizards, CoCl2 tended to reverse it. It appears that methylene blue acts as a potentiator of alloxan; CoCl2, on the contrary, showed clear anti-ageing effects.

The possible role of glucose-6-phosphate dehydrogenase in the detoxification of methyl parathion

The levels of proteins, glucose and glucose-6-phosphate dehydrogenase activity were studied in muscle, gill and liver tissues of the fish Tilapia mossambica under sublethal methyl parathion toxicity. Tissue glucose levels decreased with increased soluble protein content and the activity levels of glucose-6-phosphate dehydrogenase were elevated considerably. These results are discussed in relation to the involvement of glucose-6-phosphate dehydrogenase in both synthetic and detoxification processes as an adaptive response against methyl parathion toxicity.

Alloxan-induced changes in the collagen characteristics in the skin of male garden lizards, Calotes versicolor, from three age groups

Alloxan diabetes in lizards Calotes versicolor, belonging to three age groups, induced decreased levels of percentage of solubility of collagen in dorsal and ventral skin regions after 7 days of treatment. Old lizards showed greater susceptibility to alloxan diabetes than lizards of the young and middle-age groups. There appears to be no correlation between blood-glucose level and accelerated ageing of collagen. It is suggested that, in alloxan diabetes, metabolites formed in the tissues might accelerate the ageing of collagen.

Tissue compensatory metabolic profiles in Tilapia mossambica (Peters) on acclimation to sublethal acidic and alkaline media. Gill glycogen metabolism

Freshwater Fish, Tilapia mossambica (Peters) was acclimated to sublethal acidic and alkaline media and branchial tissue glycogen metabolism was studied. In acidic media, the glycogenolysis is elevated in the tissues and glycolysis is suppressed. In contrast, in alkaline media, the tissue glycolytic pathway is accelerated with accumulation of organic acids. In both the cases tissue had elevated G-6-PDH activity indicating stress conditions on the tissue metabolism. The tissue compensatory changes provided survival value to the fish under altered pH media.

Metabolic profiles of prostate gland after the administration of prolactin and bromocriptine

Wistar strain male albino rats were treated with prolactin (PRL) and bromocriptine to induce hyper- and hypoprolactinemia respectively and prostatic metabolic profiles were analysed. The energy metabolism of prostate was activated by PRL and inhibited by bromocriptine. The androgen-dependent metabolic phases of ventral prostate such as glycogenolysis, glycolysis, hexose monophosphate shunt were activated in the presence of PRL and inhibited in the presence of bromocriptine. The activities of markers of monosaccharide formation were elevated by PRL and inhibited by bromocriptine. The amino-acid oxidations and transaminations were accelerated by PRL and suppressed by bromocriptine. Hence, PRL-mediated activation of seminal plasma in the ventral prostate is suggested.

Biological time-related changes in tolerance of male rats to hypoxia--I. Survival rate and carbohydrate metabolism

Investigations were carried out on male Wistar rats, synchronized in standard conditions to a light-dark regiment (LD 12:12 with L from 0600 to 1800). Rats exposed to hypoxia equivalent to 10,500m at a clock-hour of 1000 had a survival time twice as long as that of animals exposed at 2200. Data from this study indicate the ability to mobilize energy stores through the conversion of liver glycogen to glucose along with circadian differences in hormonal response (e.g. corticosterone and insulin) contributes to the tolerance to hypoxia being greater during diurnal rest than nocturnal activity in rats.

Effect of induced bilateral cryptorchidism on the carbohydrate metabolism of reproductive tissues in albino rats

Bilateral cryptorchidism was induced surgically and its effect on carbohydrate metabolism of the reproductive tissue in albino rats analysed. In the reproductive tissues glycogenolysis was inhibited and lactic acid accumulated. The energy metabolism of the tissues was inhibited following the suppression of androgen-dependent enzymes activities. The importance of these modulations in the reproductive tissue carbohydrate metabolism on the male fertility was discussed.

Induced muscular work overload and disuse on the serum carbohydrate metabolism of dog, Canis domesticus

Serum carbohydrate metabolism was analysed in control, control stimulated, denervation atrophied and denervation stimulated dogs, Canis domesticus. The muscular training has resulted in the hypoglycemia through the mobilization of glucose into both hexose mono- and diphosphate pathways. The denervation atrophy, on the contrary, resulted in hyperglycemia because of exactly opposite changes in the carbohydrate metabolism in the serum and also possibly due to the lack of uptake by the muscle. The training programme of electrical stimulation applied to this denervated muscle has wiped off the hyperglycemia. The importance of muscular work in modulating the serum carbohydrate metabolism was indicated.

Effect of organophosphate pesticide Sumithion (Fenitrothion) on some aspects of carbohydrate metabolism in a freshwater fish, Sarotherodon (Tilapia) mossambicus (Peters)

A lethal (Lc50/48 h - 6 mg/l) concentration of the organophosphate (OP) pesticide Sumithion increased blood glucose levels and phosphorylase activity, but hepatic glycogen registered a fall which indicated that the observed hyperglycemia was due to breakdown of hepatic glycogen.

A study of the relationship between the energy contents of Schistosoma mansoni cercariae and their death during penetration of mammalian host skin

Immersion of Biomphalaria pfeifferi in 1.5% glucose solution showed that the snails did not absorb any glucose during the first six hours but that almost 30% of the glucose was absorbed after 24 hours. The glycogen content of such "glucose-fed" snails was much higher than that of control normal snails. Cercariae of S. mansoni collected from the former snails exhibited a much lower level of death (20%), during penetration of mouse skin, than that of control normal cercariae (36%). It is suggested that death of S. mansoni cercariae during penetration of mammalian host skin is probably due to exhaustion of their energy reserves.

Hematological and biochemical effects of chronic CO exposure on the Japanese quail

Japanese Quail were exposed to a concentration of 300 to 350 ppm CO to maintain an equilibrium carboxyhemoglobin concentration of 30% for a period of 4 weeks. Compared to a control group of birds maintained in an identical chamber, the CO-exposed quail demonstrated increases in hematocrit ratio and hemoglobin concentration. At the end of the exposure period, the CO-exposed quail had significantly larger plasma and blood volumes, slight but significant right ventricular hypertrophy and higher fasting plasma glucose concentrations than the control birds. Cardiac and skeletal muscle carbohydrate stores were not affected by chronic CO exposure.

Studies of the metabolic activity of leukocytes from patients with a genetic abnormality of phagocytic function

Polymorphonuclear leukocytes from patients with chronic granulomatous disease respond to the phagocytosis of latex particles with normal increments in glucose consumption, lactate production, Krebs' cycle activity, and lipid turnover. The leukocytes of these patients fail to show normal increments in respiration, direct oxidation of glucose, and hydrogen peroxide formation during particle uptake. It appears that the stimulation of respiration with the formation of hydrogen peroxide and stimulation of the direct oxidative pathway of glucose metabolism are closely linked to degranulation and intracellular killing of bacteria by polymorphonuclear leukocytes.