Changes In Glycogen Content Research Articles

Environmental influence on summer survival of Manila Clam Ruditapes philippinarum: A case study in an aquaculture bay

The aquaculture of Manila clam (Ruditapes philippinarum) is under threat due to its high mortality in summer. To investigate the environmental influence on mortality of the species, we have conducted field surveys in the aquaculture area in Laizhou Bay, during the summers of 2019 and 2020. Environmental and biological data were collected. The results of data analysis have shown that in 2020, large-scale mortality events were not recorded and spatial variations of environmental variables were no significant within the survey area. However, in August 2019, significant variations of environmental variables were detected in the middle tidal area. This area was charactered with relatively high-water temperature (with maximum temperature of 31.49 °C and mean value of 26.17 ± 1.62 °C), elevated hydrogen sulfide concentrations (with a maximum concentration of 24.72 μmol/L and a mean concentration of 7.89 ± 4.14 μmol/L), and low dissolved oxygen concentrations (with a minimum concentration of 3.35 mg/L and a mean concentration of 6.27 ± 0.42 mg/L). Correspondingly, high mortality of the clam was recorded in the area, the abundance of live Manila clams has decreased by 80%. No significant abnormalities of environmental variables and clam growth were observed in other regions in 2019. Glycogen content and condition index of the clam were analyzed to investigate the relationship between environmental stress and the health of the clam. Compared to the condition index, glycogen content is a more sensitive indicator of the health status of the clam because changes in glycogen content appeared earlier than changes in condition index and mortality. A principal component analysis further indicated that the high mortality of the clam corresponds with a few environmental variables, including elevated temperature, hypoxia and the concentration of hydrogen sulfide. The simultaneous presence of these multiple environmental stressors could have triggered alterations in the physiological responses of the clam.

Chloroacetonitrile reduces rat prenatal bone length and induces oxidative stress, apoptosis, and DNA damage in rat fetal liver.

One of the disinfection byproducts of chlorinating drinking water is chloroacetonitrile (CAN). Thirty-six female rats were used and distributed equally into four groups. The low dose treated group received CAN at a dose of 5.5mg/kg body weight/day (1/40 LD50 ) orally from the 6th to 12th day of gestation. The high dose treated group received 11 mg/kg body weight/day (1/20 LD50 ) of CAN orally for the same period, the vehicle control group received 1mL of corn oil, and the water control group received 1mL of distilled water orally for the same period. High dose exposure to CAN significantly reduced gravid uterine weight, fetal body weights, and length, and caused obvious skeletal deformities, weak mineralization. Fetal tibial growth plates displayed histopathologic changes. Induced oxidative stress and redox imbalance in fetal liver tissues was evidenced by significantly decreased in catalase and superoxide dismutase activity, and elevated malondialdehyde levels. Histopathological, glycogen content changes, and DNA damage were observed in the fetal liver of high dose treated group. Additionally, administration of high dose of CAN induced apoptosis, evidenced by increased caspase-3 concentration in fetal liver. Thus, extensive exposure to CAN induces poor pregnancy outcomes. CAN levels in water should be monitored regularly.

Sexual Dimorphism in Metabolic Responses to Western Diet in Drosophila melanogaster.

Obesity is a chronic disease affecting millions of people worldwide. The fruit fly (Drosophila melanogaster) is an interesting research model to study metabolic and transcriptomic responses to obesogenic diets. However, the sex-specific differences in these responses are still understudied and perhaps underestimated. In this study, we exposed adult male and female Dahomey fruit flies to a standard diet supplemented with sugar, fat, or a combination of both. The exposure to a diet supplemented with 10% sugar and 10% fat efficiently induced an increase in the lipid content in flies, a hallmark for obesity. This increase in lipid content was more prominent in males, while females displayed significant changes in glycogen content. A strong effect of the diets on the ovarian size and number of ma-ture oocytes was also present in females exposed to diets supplemented with fat and a combina-tion of fat and sugar. In both males and females, fat body morphology changed and was associ-ated with an increase in lipid content of fat cells in response to the diets. The expression of me-tabolism-related genes also displayed a strong sexually dimorphic response under normal condi-tions and in response to sugar and/or fat-supplemented diets. Here, we show that the exposure of adult fruit flies to an obesogenic diet containing both sugar and fat allowed studying sexual dimorphism in metabolism and the expression of genes regulating metabolism.

Neither Peristaltic Pulse Dynamic Compressions nor Heat Therapy Accelerate Glycogen Resynthesis after Intermittent Running.

To investigate the effects of a single session of either peristaltic pulse dynamic leg compressions (PPDC) or local heat therapy (HT) after prolonged intermittent shuttle running on skeletal muscle glycogen content, muscle function, and the expression of factors involved in skeletal muscle remodeling. Twenty-six trained individuals were randomly allocated to either a PPDC (n = 13) or a HT (n = 13) group. After completing a 90-min session of intermittent shuttle running, participants consumed 0.3 g·kg-1 protein plus 1.0 g·kg-1 carbohydrate and received either PPDC or HT for 60 min in one randomly selected leg, while the opposite leg served as control. Muscle biopsies from both legs were obtained before and after exposure to the treatments. Muscle function and soreness were also evaluated before, immediately after, and 24 h after the exercise bout. The changes in glycogen content were similar (P > 0.05) between the thigh exposed to PPDC and the control thigh ~90 min (Control: 14.9 ± 34.3 vs PPDC: 29.6 ± 34 mmol·kg-1 wet wt) and ~210 min (Control: 45.8 ± 40.7 vs PPDC: 52 ± 25.3 mmol·kg-1 wet wt) after the treatment. There were also no differences in the change in glycogen content between thighs ~90 min (Control: 35.9 ± 26.1 vs HT: 38.7 ± 21.3 mmol·kg-1 wet wt) and ~210 min (Control: 61.4 ± 50.6 vs HT: 63.4 ± 17.5 mmol·kg-1 wet wt) after local HT. The changes in peak torque and fatigue resistance of the knee extensors, muscle soreness, and the mRNA expression and protein abundance of select factors were also similar (P > 0.05) in both thighs, irrespective of the treatment. A single 1-h session of either PPDC or local HT does not accelerate glycogen resynthesis and the recovery of muscle function after prolonged intermittent shuttle running.

Arginine supplementation prevent diabetic mellitus complications on myopathy and visceral organs (liver&pancreas)in experimental model.

The study was designed to investigate the role of arginine on myopathy and some visceral organs like liver and pancreas in diabetic female rats at different period (15,30,45) days post diabetic induction.In this study female rats ( Rattus norvegicus) were used, total number (30) rats were divided into ( non-diabetic and diabetic ) groups, first group with (6) females as control group and diabetic group with (24) rats, this group subdivided into two groups (12) rats on each one, both of them was injected intraperitoneally with single dose about ( 60 mg/kg) B/W from streptozotocin (STZ) with (12) rats at each period (15,30,45) days post (DM) induction one of this two subgroup were given only tap water but the second subgroup (diabetic and treated with arginine)were given L-arginine dissolved in the drinking water as (10mg/L) after (3) days post (STZ) induction.At (15) day post induction the skeletal muscles revealed to atrophied muscle fibers, infarction, irregular, crowded myonuclei, infiltration of inflammatory cells, tapers endings. Moreover at (30) days sever atrophied muscle fibers, myonuclei was detached from their normal location, thick, dark sarcolemma with zigzag shape, while post (45) day sever alterations included filamentous muscle fibers, some completely destructed, wavy fibers, bifurcated and other rounded or circular muscle fibers. The study determined the effect of arginine on diabetic skeletal muscles, post (15) days of induction, the muscle fibers more regular, clear striation, peripheral myonuclei and parallel muscle fibers. post (30) days, normal muscle fibers, number of satellite cells, normal capillaries, regenerated myotubes. At (45) days the muscle fibers with normal diameter, more intense, less inflammation, normal muscle spindles, less congested blood vessels and normal blood walls thickness.Liver sections related to diabetes group showed post (15) days vacuolated hepatocytes with pyknotic nuclei, dilated sinusoids, increased in kupffer cells, mild fatty changes, bile ducts hyperplasia. Post (30) days sever congestion, necrotic foci, hydropic changes, cloudy hepatocytes, swelling with pyknotic nuclei. At (45) days more severity included necrosis, kupffer cells hyperplasia, sever fibrosis, fatty changes. Role of arginine was determined and its effect on liver, after (15) day normal hepatocytes, more regular hepatic plates, mild inflammation, normal periportal area, post (30) days remarkable regeneration, foci of kupffer cells accumulated, proliferation of bile ductules and mild congestion, at (45) days liver structure resemble the control, most hepatocytes was binucleat, arrange in hepatic cords and normal sinusoid.Harmful effect of (DM) on pancreatic tissue which showed after (15) day, shrinkage of Langerhans islets, atrophied pancreatic acini, destruction and necrosis of beta cells, reduced number and size of islets, changes more severity at (30,45) days, revealed to atrophy stroma replaced by fibrous and adipose connective tissue substance, vacuolated and degenerated islets. Whereas pancreas from diabetic rats treated with arginine after (15) day the changes less obvious, more numerous islet of Lankerhanse, regular acini and at (30,45) day normal pancreatic tissue, most islets with normal boundaries, organized pancreatic acini and the protective role on pancreas was noticed.(DM) caused variable changes in glycogen content in both skeletal muscles and liver at each period (15, 30, 45) days. Moreover the results determined the role of arginine on accumulation and stored of glycogen content. The liver from diabetic rats showed the same results and there was mild reduction to moderate and then sever reduction in glycogen content at each period (15,30,45) days respectively whereas restored in glycogen content recorded on rats treated with arginine.The study evaluated changes in cholesterol and Triglycerides( TG) level and the results showed a significant increase at (P<0.05) in their level in all diabetic rats compared to control while significant decrease at (P<0.05) in level of cholesterol and (TG) in rats with (DM) and treated with arginine. Moreover (HDL) showed a significant decrease at (P<0.05) of diabetic rats and there was increase in its concentration in all diabetes rats treated with arginine. Also insulin growth factor like-1 (IGF-1) in all rats related to control and treated group was estimated, the data clarified a significant decrease at (P<0.05) within diabetic group compared to control, while significant increase in rats related to treated group compared to diabetic group.

A novel phosphoglucomutase-deficient mouse model reveals aberrant glycosylation and early embryonic lethality.

Patients with phosphoglucomutase (PGM1) deficiency, a congenital disorder of glycosylation (CDG) suffer from multiple disease phenotypes. Midline cleft defects are present at birth. Overtime, additional clinical phenotypes, which include severe hypoglycemia, hepatopathy, growth retardation, hormonal deficiencies, hemostatic anomalies, frequently lethal, early-onset of dilated cardiomyopathy and myopathy emerge, reflecting the central roles of the enzyme in (glycogen) metabolism and glycosylation. To delineate the pathophysiology of the tissue-specific disease phenotypes, we constructed a constitutive Pgm2 (mouse ortholog of human PGM1)-knockout (KO) mouse model using CRISPR-Cas9 technology. After multiple crosses between heterozygous parents, we were unable to identify homozygous life births in 78 newborn pups (P = 1.59897E-06), suggesting an embryonic lethality phenotype in the homozygotes. Ultrasound studies of the course of pregnancy confirmed Pgm2-deficient pups succumb before E9.5. Oral galactose supplementation (9 mg/mL drinking water) did not rescue the lethality. Biochemical studies of tissues and skin fibroblasts harvested from heterozygous animals confirmed reduced Pgm2 enzyme activity and abundance, but no change in glycogen content. However, glycomics analyses in serum revealed an abnormal glycosylation pattern in the Pgm2+/- animals, similar to that seen in PGM1-CDG.

Cold Acclimation of Trogoderma granarium Everts Is Tightly Linked to Regulation of Enzyme Activity, Energy Content, and Ion Concentration.

In this study, cold hardiness and some physiological characteristics of the Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) larvae, were investigated under different thermal regimes, i.e., control, cold-acclimated (CA), fluctuating-acclimated (FA), and rapid cold-hardened (RCH). In all the regimes, the larval survival rate decreased with a decrease in temperature. CA larvae showed the highest cold hardiness following 24 h exposure at -15 and -20°C. Control larvae had the highest glycogen content (34.4 ± 2.3 μg/dry weight). In contrast, CA larvae had the lowest glycogen content (23.0 ± 1.6 μg/dry weight). Change in trehalose content was reversely proportional to changes in glycogen content. The highest myo-inositol and glucose contents were detected in CA larvae (10.7 ± 0.4 μg/dry weight) and control (0.49 ± 0.03 μg/dry weight), respectively. In control and treated larvae, [Na+] decreased, though [K+] increased, with increasing exposure time. The shape of the thermal reaction curve of AMP-depended protein kinase and protein phosphatase 2C followed the same norm, which was different from protein phosphatase 1 and protein phosphatase 2A. Protein phosphatase 2A and 2C showed a complete difference in thermal reaction norms. Indeed, thermal fluctuation caused the highest changes in the activity of the enzymes, whereas the RCH showed the lowest changes in the activity of the enzymes. Our results showed a significant enhancement of larval cold tolerance under CA regime, which is related to the high levels of low molecular weight carbohydrates under this regime. Our results showed that among the different thermal regimes tested, the CA larvae had the lowest supercooling point (about -22°C) and the highest cold hardiness following 24 h exposure at -15 and -20°C.

Changes in glycogen concentration and gene expression levels of glycogen-metabolizing enzymes in muscle and liver of developing masu salmon

Glycogen, as an intracellular deposit of polysaccharide, takes important roles in energy balance of many animals. In fish, however, the role of glycogen during development is poorly understood. In the present study, we assessed changes in glycogen concentration and gene expression patterns of glycogen-metabolizing enzymes in developing masu salmon (Oncorhynchus masou masou), a salmonid species inhabiting west side of North Pacific Ocean. As we measured glycogen levels in the bodies and yolk sacs containing the liver separately, the glycogen concentration increased in both parts as the fish developed, whereas it transiently decreased in the yolk sac after hatching, implying glycogen synthesis and breakdown in these tissues. Immunofluorescence staining using anti-glycogen monoclonal antibody revealed localization of glycogen in the liver, muscle and yolk syncytial layer of the pre-hatching embryos and hatched larvae. In order to estimate glycogen metabolism in the fish, the genes encoding homologs of glycogen synthase (gys1 and gys2) and glycogen phosphorylase (pygma, pygmb and pygl) were cloned, and their expression patterns were assessed by quantitative PCR and in situ hybridization. In the fish, gys1 and gys2 were robustly expressed in the muscle and liver, respectively. Also, expression of pyg isoforms was found in muscle, liver and yolk syncytial layer during hatching. With changes in glycogen concentration and expression patterns of relevant genes, our results suggest, for the first time, possible involvement of glycogen in energy balance of fish embryos, especially during hatching.

Modulatory effects of Caralluma fimbriata extract against high-fat diet induced abnormalities in carbohydrate metabolism in Wistar rats

The present study was aimed to evaluate the modulatory effects of hydroalcoholic extract of Caralluma fimbriata (CFE) by assaying the activities of key enzymes of carbohydrate metabolism and changes in glycogen content (liver and muscle) in high-fat (HF) diet-induced diabetic rats. In vitro glucose uptake studies were carried out in both psoas muscle and adipose tissue. The inhibitory effect of the extract on α-amylase was determined in in vitro studies. Male Wistar rats of body weight around 180g were divided into five groups (n=8), two of these groups were fed with standard pellet diet and the other three groups were fed with HF- (60%) diet. CFE (200mg/kg body weight/day) was administered through oral route to each group of standard pellet diet rats and HF-fed rats and Metformin (Met) (20mg/kg body weight/day) was administered through oral route to HFD+Met group for 90 days. At the end of the experimental period, biochemical parameters related to glycogen content in liver and muscle, and intestinal disaccharidases like maltase, sucrase and lactase were assayed. Alterations in the activities of enzymes of glucose metabolism (hexokinase, phosphorfructoki nase, pyruvate kinase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, and glucose-6-phosphate dehydrogenase), intestinal disaccharidases and glycogen content as observed in the high fat diet-fed rats were prevented with CFE/Met administration. From this study, we observed that CFE/Met could significantly restore the levels of glycogen in liver and muscle and key enzymes of carbohydrate metabolism to near normal in groups-HFD+CFE and HFD+Met. The skeletal muscle of HF-diet fed rats showed degenerative changes of muscle myofibers with fat deposition. These changes were attenuated in the HFD group treated with CFE/Met and retained their normal structure appearance. It can be concluded from these results that CFE might be of value in reducing the alterations related to carbohydrate metabolism under high calorie diet consumption.

Diapause and Cold Hardiness of the Almond Wasp, Eurytoma amygdali (Hymenoptera: Eurytomidae), Two Independent Phenomena.

The almond wasp, Eurytoma amygdali Enderlein (Hymenoptera: Eurytomidae), a key pest of almond, is a univoltine pest diapausing as last instar larvae inside the damaged fruits for almost nine months in a year. In this study, changes in the amount of total simple sugars, lipid, protein, glycogen, trehalose, glucose, supercooling points (SCPs), and cold hardiness of the diapausing larvae were measured from October to March for first year diapause-destined and in August and September for second year diapause-destined larvae. Changes in glycogen content were reversely proportional to changes in total simple sugars and low molecular weight carbohydrates. These changes reflect the interconversion of glycogen to sugar alcohol in order to increase the insect cold tolerance. We found that cold hardiness and diapause of the last instar larvae of the almond wasp have evolved separately. Cold hardiness was highly associated with physiological changes (accumulation of cryoprotectants), but no physiological changes occurred in early diapause of first year diapause-destined and second year diapause-destined larvae. The almond wasp larvae were found to be a freeze-avoidant insect, as no larva survived after SCP determination and crystallization of its body fluids.

Treating Bos indicus bulls with rumen transfaunation after 24 hours of transportation does not replete muscle glycogen

Twelve Bos indicus bulls were allocated to one of two treatment groups: rumen transfaunation (n = 6) given 10 kg of rumen fluid after transport or Control (n = 6), given 10 kg of deionised water after transport. Glycogen concentrations of the M. semimembranosus, M. semitendinosis and M. longisimus dorsi were measured before transport on Day –7 and after transport on Day 0, Day 1, Day 4 and Day 9. Feed intake, liveweight gain, plasma metabolites and electrolytes were recorded on the sampling days. Rumen transfaunation increased the dry matter intake of treated bulls compared with the bulls treated with deionised water. Rumen transfaunation had no effect on glycogen concentrations of the M. semimembranosus, M. semitendinosis and M. longisimus dorsi compared with the bulls treated with deionised water. The M. semimembranosus and the M. semitendinosis decreased in glycogen concentration immediately after transport on Day 0 but repleted to pre-transportation concentrations within 1 day. However, the M. longisimus dorsi demonstrated no change in glycogen concentration between the pre-transportation sample on Day –7 and Day 0 or Day 1 after transportation. The M. longisimus dorsi of the bulls increased in glycogen concentration between Day 1 and Day 4 after transportation. The bulls in this experiment demonstrated that muscle glycogen, as measured at the M. longissimus dorsi, cannot recover to sufficient concentrations (40–45 µmol of glycogen concentration per gram muscle) to ensure normal meat quality until between 1 and 4 days of rest when feeding Rhodes grass hay ad libitum.

Corticosterone alters materno-fetal glucose partitioning and insulin signalling in pregnant mice.

Glucocorticoids affect glucose metabolism in adults and fetuses, although their effects on materno-fetal glucose partitioning remain unknown. The present study measured maternal hepatic glucose handling and placental glucose transport together with insulin signalling in these tissues in mice drinking corticosterone either from day (D) 11 to D16 or D14 to D19 of pregnancy (term = D21). On the final day of administration, corticosterone-treated mice were hyperinsulinaemic (P < 0.05) but normoglycaemic compared to untreated controls. In maternal liver, there was no change in glycogen content or glucose 6-phosphatase activity but increased Slc2a2 glucose transporter expression in corticosterone-treated mice, on D16 only (P < 0.05). On D19, but not D16, transplacental (3) H-methyl-d-glucose clearance was reduced by 33% in corticosterone-treated dams (P < 0.05). However, when corticosterone-treated animals were pair-fed to control intake, aiming to prevent the corticosterone-induced increase in food consumption, (3) H-methyl-d-glucose clearance was similar to the controls. Depending upon gestational age, corticosterone treatment increased phosphorylation of the insulin-signalling proteins, protein kinase B (Akt) and glycogen synthase-kinase 3β, in maternal liver (P < 0.05) but not placenta (P > 0.05). Insulin receptor and insulin-like growth factor type I receptor abundance did not differ with treatment in either tissue. Corticosterone upregulated the stress-inducible mechanistic target of rapamycin (mTOR) suppressor, Redd1, in liver (D16 and D19) and placenta (D19), in ad libitum fed animals (P < 0.05). Concomitantly, hepatic protein content and placental weight were reduced on D19 (P < 0.05), in association with altered abundance and/or phosphorylation of signalling proteins downstream of mTOR. Taken together, the data indicate that maternal glucocorticoid excess reduces fetal growth partially by altering placental glucose transport and mTOR signalling.

Seasonal Changes in Glycogen Contents in Various Tissues of the Edible Bivalves, Pen ShellAtrina lischkeana, Ark ShellScapharca kagoshimensis, and Manila ClamRuditapes philippinarumin West Japan

The types of tissues accumulating glycogen and seasonal changes in glycogen content were investigated in the following shell species: pen shellAtrina lischkeana, ark shellScapharca kagoshimensis, and Manila clamRuditapes philippinarum. Comparison of the results showed that the adductor muscle or foot was the main glycogen reservoir and the levels varied seasonally. The adductor muscle in the pen shell showed higher glycogen content during spring and lower content during autumn. The ark shell, on the other hand, showed higher content during winter and spring and lower content during summer and autumn, while the Manila clam showed higher glycogen content during spring and summer and lower content during autumn and winter. These results revealed that the adductor muscle in pen shells and the foot in ark shells and Manila clams act as the main storage tissues for glycogen in the three species studied and that these tissues are suitable to analyze glycogen prevalence to estimate individual physiological condition.

Effect of Lung Fibrosis on Glycogen Content in Different Extrapulmonary Tissues

Patients with pulmonary fibrosis often exhibit reduced lung function and diminished health-related quality of life. Studies have shown that paraquat-induced, extrapulmonary, acute lung injury affects the metabolic profile of glycogen content in different tissues. The purpose of the present study was to investigate whether the process of pulmonary fibrosis induced by continuous exposure to the toxic herbicide paraquat or by a local insult from bleomycin affects the glycogen content in tissues. In the paraquat experiment, Wistar rats (n=5 per group) received either saline (controls) or an intraperitoneal injection of a paraquat solution (7.0mg/kg; experimental group) once a week for 4weeks. In the bleomycin experiment, Balb/c mice (n=5 per group) received either saline (controls) or 6.25U/kg of bleomycin through intratracheal instillation in single dose (experimental group). Glycogen content in different tissues (mg/g tissue) was measured using the anthrone reagent. The lungs submitted to histopathological and quantitative analyses of fibrosis. Paraquat-induced fibrosis led to lower glycogen content in the gastrocnemius muscle (2.7±0.1 vs. 3.4±0.1; 79%) compared with the controls, whereas no changes in glycogen content were found in the diaphragm or heart. Bleomycin-induced fibrosis led to lower glycogen content in the diaphragm (0.43±0.02 vs. 0.79±0.09, 54%), gastrocnemius muscle (0.62±0.11 vs. 1.18±0.06, 52%), and heart (0.68±0.11 vs. 1.39±0.1, 49%) compared with the controls (p<0.05). Moreover, the area of fibrous connective tissue (μm(2)) in the lungs was significantly increased in paraquat-induced fibrosis (3,463±377 vs. 565±89) and bleomycin-induced fibrosis (3,707±433.9 vs. 179±51.28) compared with the controls. The findings suggest that the effects of fibrogenesis in the lungs are not limited to local alterations but also lead to a reduction in glycogen content in the heart and other muscles. This reduction could partially explain the impaired muscle performance found in patients with pulmonary fibrosis.

Changes in Glycogen Content During Fin Regeneration

Regeneration is the replacement of the lost parts. Amputation was carried out through the ventral and the pelvic fin at a proximal level of Oreochromisaureus. The regeneration process has been divided into five continuous stages: wound healing, dedifferentiation stage, blastema formation stage, early and late redifferentiation and growth stages. The regenerating system was completely formed histologically by about fifteen days post-amputation. During this stage the fin grew by increasing the number of segments, rather than by increasing the length of skeletal elements. By the thirtieth day postamputation, the fin regenerate illustrated the entire histological pattern of fin regeneration. Then the growth of the regenerating fins continued by addition of new lepidotrichial segments to the end of the fin, reaching approximately the normal length and size by the forty-five day. The steady increase of glycogen content in the regenerating fins, reaching its highest level at the early redifferentiation stage met the problem of energetics, much needed during this active proliferated phase. In addition, the decrease in the glycogen content in the liver and muscles during the early phases of regeneration was indicative of the increased energy demands associated with the process of regeneration in the fish body as a whole.

Ethanolic extract of Commiphora mukul gum resin attenuates streptozotocin-induced alterations in carbohydrate and lipid metabolism in rats.

The purpose of this study was to investigate the effects of Commiphora mukul gum resin ethanolic extract (CMEEt) administration against altered activities of key enzymes of carbohydrate metabolism, lipid metabolism and changes in glycogen content (liver and muscle) and lipids (liver and heart) in streptozotocin (STZ) induced insulin deficient diabetic Wistar albino rats. Diabetes was induced by intraperitoneal injection of STZ (55 mg/kg body wt) to male Wistar rats. The animals were divided into four groups: Control (C), control-treated (C+CM), diabetic (D) and diabetic-treated group (D+CM). Diabetic-treated and control-treated rats were treated with C. mukul gum resin ethanolic extract (CMEEt) in 2 ml distilled water, orally (200 mg/kg body weight/day for 60 days). At the end of the experimental period, biochemical parameters related to carbohydrate and lipid metabolism were assayed. The significant enhancement in tissue lipids (heart and liver) total cholesterol, triglycerides, phospholipids and free fatty acids of diabetic rats were nearer to normalized in diabetic treated rats (D+CM). Alterations in the activities of enzymes of glucose metabolism (hexokinase, phosphofructokinase, pyruvate kinase, and glucose-6-phosphatase, fructose-1,6-bisphosphatase and glucose-6-phosphate dehydrogenase) and lipid metabolism (fatty acid synthase, malic enzyme and lipoprotein lipase) as observed in diabetic (D) rats were prevented with CMEEt administration. In conclusion, our findings indicate improvement of glucose and lipid metabolisms in STZ induced diabetic rats by treatment with Commiphora mukul and suggest that the plant can be used as an adjuvant for the prevention and/or management of insulin deficiency and disorder related to it.

A comparison of fiber specific and whole muscle homogenate markers of muscle activation following HIT and END exercise

Muscle activation following a bout of high‐intensity interval training (HIT) and endurance exercise (END) was examined in recreationally active men (n=6; age, 19.3±1.4 yrs; VO2peak, 51.9±5.1 ml/min/kg; WRpeak, 264.1±41.6 W). Muscle biopsies were obtained at rest and immediately following a bout of HIT (8 20s intervals, separated by 10s rest, at 170% WRpeak; 481.4±60.1 W) and END (30min of steady state cycling at 65% of WRpeak; 173.7±29.8 W). Bouts were performed a minimum of 1 week apart in random order. MHC expression was identified via immunofluorescent staining while glycogen content was determined via PAS staining. Changes in phosphorylated AMPK (p‐AMPK) and mTOR (p‐mTOR) were determined in whole muscle homogenates via western blotting. Changes in glycogen content were only examined in type I and IIA fibers as only 8 and 16 of 24 samples contained IIX and IIAX fibers, respectively. Significant (p&lt;0.05) glycogen depletion was observed in both type I (HIT −55% END −42%) and IIA (HIT −49%; END −72%) fibers following both protocols but was greater (p&lt;0.05) in type IIA fibers following END than HIT. Interestingly, whole muscle markers of activation, p‐AMPK and p‐mTOR were only elevated (p&lt;0.01) following END (HIT: p‐AMPK, p=0.34; p‐mTOR, p=0.50). These data suggest that use of p‐AMPK and p‐mTOR as markers of whole muscle activation may not be appropriate following HIT. This research was supported by NSERC.

The Influence of Temperature on the Content of Liver Glycogen and Muscle Glycogen in Sparrow

The sparrows for experimental materials were divided into 5 °C acclimation group, 30 °C acclimation group and control group. The content of liver glycogen and muscle glycogen were measured with sulfuric acid-anthrone colorimetric method after two weeks of acclimation. The results show that: When the temperature is 5 °C, the glycogen content was very significantly lower than the glycogen content of control group (p0.05); The change in glycogen content was extremely significant between the two temperature (p&lt;0.01).

Glycogen Accumulation and Degradation by the Trichomonads Trichomonas vaginalis and Trichomonas tenax

Several species of trichomonad have been shown to accumulate significant quantities of glycogen during growth, suggesting an important role for this compound in cell physiology. We provide the first analysis of the changes in glycogen content and glycogen phosphorylase activity that occur during in vitro growth of two trichomonad species: Trichomonas vaginalis and Trichomonas tenax. Both species accumulated glycogen following inoculation into fresh medium and utilized this compound during logarithmic growth. Glycogen phosphorylase activity also varied during growth in a species-specific manner. The expression of phosphorylase genes in T. vaginalis remained constant during growth and thus transcriptional control did not explain the observed fluctuations in phosphorylase activity. After cloning, expression, and purification, two recombinant glycogen phosphorylases from T. vaginalis and one recombinant glycogen phosphorylase from T. tenax had robust activity and, in contrast to many other eukaryotic glycogen phosphorylases, did not appear to be regulated by reversible protein phosphorylation. Furthermore, allosteric regulation, if present, was not mediated by compounds known to impact the activity of better characterized phosphorylases.

Raman Microscopy of Human Embryonic Stem Cells Exposed to Heat and Cold Stress

Human embryonic stem cells (hESCs) have large nucleus-to-cytoplasm ratios and nucleic acid spectral bands are prominent in their characteristic Raman signatures. Under normal conditions, the major variations in these signatures are due to changes in glycogen content, but how these signatures vary in response to different external conditions is largely unknown. In this study we investigated the influences of temperature variations on hESC Raman signatures. At 32 °C, compared to the 37 °C control condition, cell proliferation rates were markedly reduced and glycogen Raman band intensities were elevated. In addition, at both temperatures, an inverse relationship between cell proliferation rates (i.e., onset of exponential growth phase vs. end of exponential phase) and glycogen Raman band intensities was observed. This relationship suggested a role for glycogen in the energy metabolism of hESC self-renewal. Protein and lipid spectral variations were small and co-varied with those of nucleic acids, suggesting that they were related to changes in cellular dimensions occurring during the cell cycle. When the temperature was elevated to 39 °C, increased glycogen band intensities, compared to controls, were also observed. In addition, spectral evidence of differentiation emerged that was supported by reduced SSEA-3 expression. Taken together, these results demonstrated that heat and cold stress had quite different effects on the characteristic Raman signatures of hESCs. Thus, Raman spectroscopy can be used to detect deviation from optimal culturing temperatures and therefore it could be of considerable value in the routine and noninvasive determination of hESC culture quality.