Glycerol-3-phosphate Dehydrogenase Activity Research Articles

태음인(太陰人) 청심연자탕(淸心蓮子湯)의 동시분석 및 항비만 효과

Objectives We performed the simultaneous analysis for three compounds in Cheongsimyeonja-tang (CSYJT) and evaluated its anti-obesity effect. Methods The column for separation of three compounds was used Gemini <TEX>$C_{18}$</TEX> column and maintained at <TEX>$40^{\circ}C$</TEX>. The mobile phase for gradient elution consisted of two solvent systems. The analysis was carried out at a flow rate of 1.0 mL/min with PDA detection at 275 nm. The injection volume was <TEX>$10{\mu}L$</TEX>. 3T3-L1 preadipocytes were differentiated into adipocytes by adding insulin, dexamethasone and 3-isobutyl-1-methylxanthine (IBMX) for 8 days in the absence or presence of CSYJT. Anti-obesity effects of CSYJT were evaluated by Oil Red O staining, glycerol-3-phosphate dehydrogenase (GPDH) activity, triglyceride contents, and leptin production. Results Calibration curves were acquired with <TEX>$r^2$</TEX> >0.9999. The contents of baicalin, wogonoside and baicalein in CSYJT were 14.54-14.65 mg/g, 5.24-5.27 mg/g and 0.01-0.02 mg/g, respectively. CSYJT showed inhibitory effect on lipid accumulation and GPDH activity in the differentiated 3T3-L1 cells. Furthermore, CSYJT significantly decreased contents of triglyceride and leptin production in 3T3-L1 adipocytes. Conclusions These results will be helpful to improve quality control and anti-obesity effect of Taeeumin CSYJT.

태음인(太陰人) 열다한소탕(熱多寒少湯)이 3T3-L1 지방전구세포(脂肪前驅細胞) 분화(分化)에 미치는 영향(影響)

Objectives : Although Yeoldahanso-tang (YDHST) has been widely used for treatment of obesity and its related diseases such as hyperinsulinemia and hypertension for Taeeumin, no scientific evidence has reported yet to support its ability to work against these metabolic disorders. Our study was aimed to investigate the anti-obesity effect of YDHST extract on the cellular differentiation of 3T3-L1 preadipocytes into adipocytes. Methods : 3T3-L1 preadipocytes were differentiated into adipocytes by adding insulin, dexamethasone and 3-isobutyl-1-methylxanthine (IBMX) for 8 days in the absence or presence of YDHST extract. Anti-obesity effects of YDHST extract were evaluated by Oil Red O staining, glycerol-3-phosphate dehydrogenase (GPDH) activity, triglyceride contents, and leptin production. Results : YDHST extract remarkably prevented lipid accumulation with no cytotoxicity in the differentiated 3T3-L1 cells. In addition, YDHST extract decreased contents of triglyceride 3T3-L1 adipocytes. Consistently, YDHST extract caused a significant inhibition of GPDH activity and leptin production in a dose-dependent manner. Conclusions : Our findings suggest that Sasang constitutional herbal formula YDHST for Tae-eumin has anti-obesity activity by regulation of the adipogenesis process in vitro. Additional study will be required to further confirm the inhibitory effect on adipocyte differentiation by using in vivo animal model.

인삼패독산의 추출용매에 따른 성분함량 및 효능연구

Objectives : This study evaluated activities and ingredient contents concerning extracts according to extraction solvents of Insampaedok-san (IS, Renshen bai du-san). Methods : The herbal constituents of IS were extracted with water and 70% ethanol at <TEX>$100^{\circ}C$</TEX> for 2 hr. Using the HPLC system, the six ingredient contents of different solvent extracts of IS were analyzed. The nitric oxide (NO), prostaglandin <TEX>$E_2$</TEX> (<TEX>$PGE_2$</TEX>) production and proinflammatory cytokines were measured in RAW264.7 cells stimulated with lipopolysaccharide (LPS). The macrophage-derived chemokine (MDC/CCL22) and regulated on activation normal T-cell expression and secreted (RANTES/CCL5) production were measured in HaCaT and BEAS-2B cells stimulated tumor necrosis factor-<TEX>${\alpha}$</TEX> (TNF-<TEX>${\alpha}$</TEX>) and interferon-<TEX>${\gamma}$</TEX> (IFN-<TEX>${\gamma}$</TEX>). The activities of glycerol-3-phosphate dehydrogenase (GPDH) and leptin level were measured in 3T3-L1 cells. Results : The calibration curves showed good linearity (<TEX>$r^2$</TEX>=1.0000) for different concentration ranges. The contents of liquiritin, naringin, hesperidin, neohesperirin and glycyrrizin in 70% ethanol extracts of IS were relatively higher than that of water extract, however the content of ferulic acid in 70% ethanol and water extract of IS were similar. The extraction solvents of water and 70% ethanol were evaluated inhibitory effect on the production of NO, <TEX>$PGE_2$</TEX>, TNF-<TEX>${\alpha}$</TEX> and IL-6 in RAW 264.7 cells. Their extractions were inhibitory effect on production of MDC/CCL22 and RANTES/CCL5 in HaCaT cell and BEAS-2B cell, respectively. In addition, evaluated reduced on GPDH activity and leptin level in 3T3-L1 preadipocyte cell. Conclusions : Our results suggest that IS extracts were inhibitory effects of disease such as inflammation, allergies and obesity.

The endocrine disruptor mono-(2-ethylhexyl)phthalate promotes adipocyte differentiation and induces obesity in mice

The environmental obesogen hypothesis proposes that exposure to endocrine disruptors during developmental ‘window’ contributes to adipogenesis and the development of obesity. MEHP [mono-(2-ethylhexyl) phthalate], a metabolite of the widespread plasticizer DEHP [di-(2-ethylhexyl) phthalate], has been found in exposed organisms and identified as a selective PPARγ (peroxisome-proliferator-activated receptor γ) modulator. However, implication of MEHP on adipose tissue development has been poorly investigated. In the present study, we show the dose-dependent effects of MEHP on adipocyte differentiation and GPDH (glycerol-3-phosphate dehydrogenase) activity in the murine 3T3-L1 cell model. MEHP induced the expression of PPARγ as well as its target genes required for adipogenesis in vitro. Moreover, MEHP perturbed key regulators of adipogenesis and lipogenic pathway in vivo. In utero exposure to a low dose of MEHP significantly increased b.w. (body weight) and fat pad weight in male offspring at PND (postnatal day) 60. In addition, serum cholesterol, TAG (triacylglycerol) and glucose levels were also significantly elevated. These results suggest that perinatal exposure to MEHP may be expected to increase the incidence of obesity in a sex-dependent manner and can act as a potential chemical stressor for obesity and obesity-related disorders.

지방과 근육 세포주의 단독 및 공동배양을 통한 세포형태학 및 세포물질 비교 연구

본 연구는 기존 단독배양 위주로 이루어져온 세포배양 연구의 방법학적 한계의 극복과 대안을 제시하고자 지방과 근육세포주의 단독 및 공동배양에서 배양기법에 따른 지방 및 근육세포의 분화에 미치는 영향을 비교 조사하고자 실시하였다. 3T3-L1 (지방세포) 및 L6 (근육세포) 세포주는 성장배지인 10% FBS/DMEM (1% Pen-Strep solution 및 0.1% Fungizone 첨가) 하에서 48h 동안 단독배양 후 5% FBS/DMEM에서 배양하였다. 분화를 위한 단독 및 공동배양에서는 지방 및 근육세포 모두 분화유도물질 없이 2% FBS/DMEM으로 배양하였고, 공동배양에서는 <TEX>$0.4{\mu}m$</TEX> insert membrane을 사용하여 6 well plate 하단에 L6 cell을, 상단에는 3T3-L1 cell을 공생시켰다. 지방 및 근육세포 분화정도 측정은 세포별 형태학적 측정과 glycerol-3-phosphate dehydrogenase (GPDH) 및 creatine kinase (CK) 분석을 통해 조사되었다. 형태학적으로 볼때 3T3-L1 세포주는 공동배양보다 단독배양 시 분화가 더욱 잘 일어났고 L6 세포주의 경우 역으로 같았다. 세포물질 분석에서는 분화배지 처리일(day 0)과 비교해 단독 및 공동배양 모두 지방세포 내 GPDH의 활성도가 유의적으로(P<0.05) 증가했음을 확인할 수 있었고 단독배양이 공동배양보다 유의적으로(P<0.05) 높은 수준의 GPDH 활성도를 보였다. L6 역시 마찬가지로 분화배지 처리일에 비하여 단독 및 공동배양 모두 CK 활성도가 유의적으로(P<0.05) 높았고, CK 활성도가 공동배양에서 유의적으로(P<0.05) 높게 나타남을 확인할 수 있었다. 이러한 결과는 기존 연구에서 이용된 단독 배양을 통한 세포 분화 결과 등은 생체와 비교 시 방법학적 한계로 인해 실제 생체 내에서는 그 분화정도가 매우 다를 것으로 생각되며, 이것은 앞으로 정확한 세포배양 결과 확보를 위해서는 단독배양보다는 공동배양기법을 사용해야 함을 의미한다. 향후 다양한 조건과 분화조절 물질들의 첨가를 통한 추가적인 공동배양실험이나 지방분화관련 분자생물학적 물질분석 등 다양한 실험 수행 시 보다 현실적이고 대량의 기초자료 확보가 가능할 것으로 판단된다. Present study was performed to investigate the effect of single and co-culture of adipocyte and muscle cell lines on cell differentiation. 3T3-L1 (adipocyte) and L6 (muscle) cell lines were single-cultured on the condition of 10% fetal bovine serum (FBS)/Dulbeco's modified eagle's medium (DMEM) for 48 h followed by culture within 5% FBS/DMEM as a growth media. Then, the growth media was replaced by differentiation media composed of 2% FBS/DMEM without additives in single- or co-culture of the 3T3-L1 and the L6 cells to induce differentiation of both cell types. In co-culture system, the 3T3-L1 and the L6 cells were grown in separated places by being seeded on a <TEX>$0.4{\mu}m$</TEX> insert membrane and on the bottom of 6 well plate, respectively. Cell differentiation was measured using morphological investigation and cytosolic analysis of glycerol-3-phosphate dehydrogenase (GPDH; for 3T3-L1) and creatine kinase (CK; for L6). Based on the GPDH results, the presence of L6 cells did not stimulate 3T3-L1 differentiation showing more differentiation of 3T3-L1 cells in the single-culture compared to the co-culture condition. In contrast, 3T3-L1 cells in the co-culture promoted differentiation of L6 cells. Enzymatic analysis supported this result showing that 3T3-L1 cells showed statistically (P<0.05) higher GPDH activity in the single-culture than the co-culture, whereas CK results of L6 cells were vice versa (P<0.05). Overall, present results may indicate that co-culture system is more reliable and precise technique compared to single-culture. Further studies on several co-culture trials including different media conditions, supplementation of differentiating substances, molecular biological analysis, etc. should be required to obtain practical and fundamental mass data.

Anti‐obesity role of adzuki bean extract containing polyphenols: in vivo and in vitro effects

The aim of this work was to evaluate the effects of polyphenol-rich adzuki bean extract on lipid metabolism, triglyceride accumulation and proinflammatory cytokine secretion in vivo and in vitro. For the in vivo study, rats were divided into four groups: group C was fed a control diet, group A was fed the control diet with 1% adzuki bean extract, group CF was fed a high fat diet, and group AF was fed a high fat diet with 1% adzuki bean extract. For the in vitro study, the ability of adzuki bean extract to suppress triglyceride incorporation, glycerol phosphate dehydrogenase activity and inflammatory response was investigated in cultured human adipocytes. Data from the animal study showed that adzuki bean extract improved lipid metabolism in both the normal and high-fat diet groups. Adzuki bean extract treatment in the high-fat group resulted in significant reductions in total hepatic lipid accumulation and lipid secretion into the feces. Incubation of adipocytes with adzuki bean extract significantly decreased triglyceride accumulation, glycerol phosphate dehydrogenase activity and inflammatory responses without affecting cell viability. The results of this study demonstrate that adzuki bean extract has high potential to serve as a natural anti-obesity agent.

Redox balance and mitochondrial glycerol phosphate dehydrogenase activity in trained rats

Free radical production is increased in many disease states and during exercise, but in the latter the concurrent stimulation of the antioxidant defense system seems to protect the organism from excessive production of reactive oxygen species. Chronic exercise can exert negative effects on the activity of mitochondrial glycerol phosphate dehydrogenase (mGPdH), which may offer some explanation for the antioxidant effects of training, since this enzyme is a relevant producer of free radicals. To test this correlation, we compared mGPdH activity, two antioxidant defense markers and two markers of oxidative stress in sedentary and trained (Tr) rats. Training was through a swimming exercise 3days a week. After 8weeks, Tr rats lasted twice as long as controls in an acute swimming test with a 5% load. Forty-eight hours after the last exercise, the animals were killed to collect blood and tissues. Tr animals presented lower body weight and visceral fat mass with lower triglyceride content in visceral fat and plasma (p<0.05). The specific activity of mGPdH in muscle mitochondria was reduced in Tr rats by 88% (p<0.05). Total antioxidant capacity, lipid peroxidation and reduced glutathione (GSH) in liver and muscle were unaltered, while plasma GSH increased by 21% (p<0.05). These data suggest a profile of successful redox equilibrium maintenance in Tr rats, with a potentially significant contribution from the lower level of mGPdH activity in muscle. This training protocol appears to be suitable for use in detailed studies of biochemical adaptations to oxidative stress.

Maternal Prolactin Inhibition during Lactation Affects Physical Performance Evaluated by Acute Exhaustive Swimming Exercise in Adult Rat Offspring

Maternal prolactin inhibition at the end of lactation programs for metabolic syndrome and hypothyroidism in adult offspring, which could negatively affect exercise performance. We evaluated the effects of maternal hypoprolactinemia in late lactation on physical performance in adult progeny. Lactating Wistar rats were treated with bromocriptine (BRO, 1 mg per day) or saline on days 19, 20, and 21 of lactation and offspring were followed until 180 days old. Physical performance was recorded in untrained rats at 90 and 180 days by an acute exhaustive swimming test (exercise group-Ex). At day 90, BRO offspring showed higher visceral fat mass, higher plasma thiobarbituric acid reactive substances, lower total antioxidant capacity, higher liver glycogen, lower glycemia, and normal insulinemia. Although thyroid hormones (TH) levels were unchanged, mitochondrial glycerol phosphate dehydrogenase (mGPD) activity was lower in muscle and in brown adipose tissue (BAT). At this age, BRO-Ex offspring showed higher exercise capacity, lower blood lactate, higher serum T3, and higher muscle and BAT mGPD activities. At day 180, BRO offspring showed central obesity, hypothyroidism, insulin resistance, and lower EDL (extensor digitorum longus) muscle glycogen with unaltered plasma oxidative stress markers. This group showed no alteration of exercise capacity or blood lactate. After exercise, EDL and liver glycogen were lower, while T3 levels, BAT and muscle mGPD activities were normalized. Liver glycogen seem to be related with higher exercise capacity in younger BRO offspring, while the loss of this temporary advantage maybe related to the hypothyroidism and insulin resistance developed with age.

Flavonol Acylglycosides from Flower of Albizia julibrissin and Their Inhibitory Effects on Lipid Accumulation in 3T3-L1 Cells

Obesity is a serious health problem worldwide. We investigated the anti-obesity effect of the flower of Albizia julibrissin DURAZZ. (Leguminosae). A 90% EtOH extract of the flower inhibited adipogenesis in 3T3-L1 preadipocytes, as well as the activity of glycerol-3-phosphate dehydrogenase (GPDH) activity. New flavonol acylglycosides (1-4) and eighteen known compounds (5-22) were isolated by bioassay-directed fractionation. These new glycosides were elucidated to be 3″-(E)-p-coumaroylquercitrin (1), 3″-(E)-feruloylquercitrin (2), 3″-(E)-cinnamoylquercitrin (3), and 2″-(E)-cinnamoylquercitrin (4) on the basis of spectroscopic and chemical analysis. These compounds inhibited adipogenesis in 3T3-L1 preadipocytes. In particular, 2 exhibited potent inhibitory effects on triglyceride accumulation. Furthermore, GPDH activity was inhibited by 2. Additionally, 2 inhibited glucose uptake in 3T3-L1 adipocytes. These results indicate that the 90% EtOH extract and compounds isolated from the flower of A. julibrissin inhibit adipogenesis in 3T3-L1 preadipocytes and may have anti-obesity effect through the inhibition of preadipocyte differentiation.

Establishment and evaluation of a new model for studying lipogenesis in grass carp (Ctenopharyngodon idella) preadipocytes

The objective of this study was to establish and evaluate a new model for studying lipogenesis in grass carp preadipocytes. The morphology characteristic from preadipocytes to mature adipocytes was observed with the microscopic morphology, and the proliferation kinetics of cells was tested by cell counting. In addition, the nature and differentiation degree of cells were evaluated using Oil Red O staining, lipase activity determination, and reverse transcription PCR (RT-PCR) assay. Morphologically, grass carp preadipocytes started to attach and grow on day 3, then they resembled fibroblasts, and most underwent attachment, proliferation, and growth arrest with subsequent accumulation of intracellular lipid droplets before becoming mature adipocytes. Glycerol-3-phosphate dehydrogenase (GPDH) activity was increased gradually during the progress of culture. Analysis of RT-PCR confirmed that peroxisome proliferator-activated receptor-γ expression patterns were consistent with my observations regarding GPDH activity. In summary, grass carp preadipocytes cultured with 10% FBS at 28°C in a humidified 5% CO2 atmosphere have high proliferation potential. Furthermore, the cells synthesize a range of markers that are consistent with this cell type. We conclude therefore that the grass carp preadipocytes described here have high capacity for lipogenesis and may, therefore, represent a unique tool for studying fish fat cell development and metabolism.

Abstract P120: Increased [ca 2+ ] e Enhances Adipocyte Development In Bone Marrow Stroma

Background: Bone marrow stroma contains adipocytes, osteoblasts, and lymphohematopoietic donor cells. With age, fatty marrow gradually predominates in bone marrow stroma and is a factor underlying age-related fracture and anemia. Thus, it is important to understand the mechanism of adipocyte development in bone marrow stroma. Bone marrow Ca 2+ levels can reach high concentrations of 8 to 40 mM, while circulating plasma Ca 2+ levels normally range from 2.3 to 2.6 mM. However, the effects of a high extracellular calcium concentration ([Ca 2+ ] e ) on adipocyte development in bone marrow stroma remain largely unknown. Methods and Results: We studied the effects of high [Ca 2+ ] e on adipocyte development in bone marrow stroma. First, we used the fura-2 method to examine whether a change in [Ca 2+ ] e alters [Ca 2+ ] i levels in bone marrow stromal cells. Changes of [Ca 2+ ] e from 1.8 mM to 5.4 mM and 10.8 mM significantly increased [Ca 2+ ] i by 1.1 and 1.3 times, respectively. Next, bone marrow stromal cells were cultured for 14 days in high [Ca 2+ ] e (5.4 mM and 10.8 mM) and normal [Ca 2+ ] e (1.8 mM) conditions. Adipocyte development was monitored by Oil Red O staining of cytoplasmic lipids and by the activity of glycerol-3-phosphate dehydrogenase (GPDH). In 5.4 mM and 10.8 mM [Ca 2+ ] e , Oil Red O-stained cells increased significantly by 1.4 and 2.3 times, respectively, and GPDH activity increased significantly by 1.7 and 2.3 times, respectively, compared with the respective values in 1.8 mM [Ca 2+ ] e . Conclusions: These results indicate that high [Ca 2+ ] e induces an increase of [Ca 2+ ] i , which enhances adipocyte development in bone marrow stroma. Further studies are required to determine the influx pathway of Ca 2+ , since prevention of Ca 2+ influx into bone marrow stromal cells might suppress development of fatty marrow and reduce age-related fracture and anemia.

Structural and Functional Properties of an Upper Airway Dilator Muscle in Aged Obese Male Rats

Background: Age, obesity and male sex are risk factors for the development of obstructive sleep apnoea syndrome. Objective: We examined structural and functional properties of the sternohyoid muscle in young lean and aged obese male rats. We hypothesized that the aged muscle would be vulnerable to oxidative stress (hypoxia). Methods: Isometric contractile and endurance properties of the sternohyoid muscle were assessed in vitro with or without the superoxide scavenger Tempol (10 mM). Muscle fibre size and density were determined by myosin heavy chain immunofluorescence. Succinate dehydrogenase (SDH) and glycerol-3- phosphate dehydrogenase (GPDH) enzyme activities were determined. Results: Fibre hypertrophy, increased fast twitch (type 2X) fibre density, decreased SDH activity and increased GPDH activity, together with increased force and fatigue, were observed in aged obese muscles compared to young lean muscles. Tempol treatment increased strength and sensitivity to stimulation. Hypoxic depression of force was ameliorated by antioxidant treatment with equivalent effects in young lean and aged obese muscle. Conclusions: We conclude that the rat sternohyoid exhibits indefinite growth and is protected from oxidative stress as the animal ages.

Reduction of Body Weight by Capsaicin is Associated with Inhibition of Glycerol-3-Phosphate Dehydrogenase Activity and Stimulation of Uncoupling Protein 2 mRNA Expression in Diet-induced Obese Rats

Capsaicin is a pungent component of red pepper, which is widely consumed as food adjuncts. The present study was performed to investigate anti-obesity effects of capsaicin in diet-induced obese rats. Male Sprague- Dawley rats (n=14) were fed with a high-fat diet (Control) or high-fat diet containing 0.016% capsaicin (w/w) (Capsaicin) for 8 weeks. The final body weight and the mass of white adipose tissue were significantly lower in capsaicin supplemented group compared to control. Dietary capsaicin ameliorated lipid profiles with decrease in the plasma concentrations of triglycerides and total cholesterol, and decrease in the levels of total lipids and triglycerides in the liver. Activity of glycerol-3-phosphate dehydrogenase (GPDH), an indicator of triglyceride biosynthesis in white adipose tissue, decreased by 35% in the group supplemented with capsaicin. However, consumption of capsaicin increased the expression of uncoupling protein 2 (UCP2) in white adipose tissue, which is related to energy consumption. Our data suggests that capsaicin may reduce body weight and fat accumulation in high fat diet-induced obese rats. These effects may be mediated, at least partially, by the upregulation of UCP2 gene expression and its ability to inhibit GPDH activity.

Cadmium inhibits the differentiation of 3T3-L1 preadipocyte through the C/EBPα and PPARγ pathways

Cadmium, a well-known toxic heavy metal, affects cellular physiology by disturbing cellular signaling pathways. We investigate the effect of cadmium on cellular differentiation using 3T3-L1 preadipocyte cell lines as an in vitro model. Here, it was shown that cadmium (3 μM) significantly decreased both glycerol-3-phosphate dehydrogenase (GPDH) activity and lipid accumulation of differentiating 3T3-L1 cells in a dose-dependent manner. In addition, inhibitory action of cadmium on differentiating 3T3-L1 cells was effective only at the initial stage of 3T3-L1 preadipocyte differentiation. Western blot analysis revealed that cadmium suppressed the expression of CCAAT/enhancer-binding protein alpha (C/EBPα) and peroxisome proliferator-activator receptor gamma (PPARγ) proteins, key transcriptional activators for adipogenesis, in a dose-dependent manner. These results suggest that the inhibitory effects of cadmium on 3T3-L1 preadipocyte differentiation, as indicated by a decrease in GPDH activity and lipid accumulation, a marker of adipogenesis, appeared to be mediated through the downregulated expression of C/EBPα and PPARγ proteins.

Activity and Transcriptional Regulation of Bacterial Protein-Like Glycerol-3-Phosphate Dehydrogenase of the Haloarchaea in Haloferax volcanii

Glycerol is a primary energy source for heterotrophic haloarchaea and a major component of "salty" biodiesel waste. Glycerol is catabolized solely by glycerol kinase (encoded by glpK) to glycerol-3-phosphate (G3P) in Haloferax volcanii. Here we characterized the next critical step of this metabolic pathway: the conversion of G3P to dihydroxyacetone phosphate by G3P dehydrogenase (G3PDH). H. volcanii harbors two putative G3PDH operons: (i) glpA1B1C1, located on the chromosome within the neighborhood of glpK, and (ii) glpA2B2C2, on megaplasmid pHV4. Analysis of knockout strains revealed that glpA1(and not glpA2) is required for growth on glycerol. However, both glpA1 and glpA2 could complement a glpA1 knockout strain (when expressed from a strong promoter in trans) and were required for the total G3PDH activity of cell lysates. The glpA1B1C1, glpK, glpF(encoding a putative glycerol facilitator), and ptsH2(encoding a homolog of the bacterial phosphotransferase system protein Hpr) genes were transcriptionally linked and appeared to be under the control of a strong, G3P-inducible promoter upstream of glpA1. Overall, this study provides fundamental insights into glycerol metabolism in H. volcanii and enhances our understanding of central metabolic pathways of haloarchaea.

Altered adipose tissue metabolism in offspring of dietary obese rat dams

To investigate further the mechanisms of developmental programming, we analysed the effects of maternal overnutrition and of postnatal high-fat feeding on adipose tissue metabolism in the offspring. Postnatal changes in serum adiponectin, leptin and TAG [triacylglycerol (triglyceride)] levels, adipose tissue TAGs, fatty acids and enzyme activities were determined in offspring of cafeteria-diet-fed dams during gestation and lactation, weaned on to standard chow or on to cafeteria diet. Obese rats showed higher adiposity (+35% to 85%) as well as a significant increase in serum glucose, insulin, leptin, adiponectin and TAG levels (P<0.01) and adipose tissue LPL (lipoprotein lipase) and GPDH (glycerol-3-phosphate dehydrogenase) activities (P<0.01), compared with control pups at weaning (day 21) and at adulthood (day 90). Adipose HSL (hormone-sensitive lipase) activity was increased only at day 90 (P<0.05), and FAS (fatty acid synthase) activity remained unchanged. The proportions of SFAs (saturated fatty acids) and MUFAs (mono-unsaturated fatty acids) and the Δ(9)-desaturation index were significantly increased (P<0.05), whereas PUFAs (polyunsaturated fatty acids) were decreased (P<0.01) in serum and adipose TAGs of obese pups compared with controls. The cafeteria diet at weaning induced more severe abnormalities in obese rats. In conclusion, maternal overnutrition induced permanent changes in adipose tissue metabolism of the offspring. These pre-existing alterations in offspring were worsened under a high-fat diet from weaning to adulthood. Consequently, adipose adipokines and enzymes could provide a potential therapeutic target, and new investigations in this field could constitute strategies to improve the impact of early-life overnutrition.

Effects ofPanicum miliaceumL. extract on adipogenic transcription factors and fatty acid accumulation in 3T3-L1 adipocytes

The dietary intake of whole grains is known to reduce the incidence of chronic diseases such as obesity, diabetes, cardiovascular disease, and cancer. To investigate whether there are anti-adipogenic activities in various Korean cereals, we assessed water extracts of nine cereals. The results showed that treatment of 3T3-L1 adipocytes with Sorghum bicolor L. Moench, Setaria italica Beauvois, or Panicum miliaceum L. extract significantly inhibited adipocyte differentiation, as determined by measuring oil red-O staining, triglyceride accumulation, and glycerol 3-phosphate dehydrogenase activity. Among the nine cereals, P. miliaceum L. showed the highest anti-adipogenic activity. The effects of P. miliaceum L. on mRNA expression of peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1, and the CCAAT/enhancer binding protein-α were evaluated, revealing that the extract significantly decreased the expression of these genes in a dose-dependent manner. Moreover, P. miliaceum L. extract changed the ratio of monounsaturated fatty acids to saturated fatty acids in adipocytes, which is related to biological activity and cell characteristics. These results suggest that some cereals efficiently suppress adipogenesis in 3T3-L1 adipocytes. In particular, the effect of P. miliaceum L. on adipocyte differentiation is associated with the downregulation of adipogenic genes and fatty acid accumulation in adipocytes.

Metabolism of glucose and xylose as single and mixed feed in Debaryomyces nepalensis NCYC 3413: production of industrially important metabolites

Efficient conversion of hexose and pentose (glucose and xylose) by a single strain is a very important factor for the production of industrially important metabolites using lignocellulose as the substrate. The kinetics of growth and polyol production by Debaryomyces nepalensis NCYC 3413 was studied under single and mixed substrate conditions. In the presence of glucose, the strain produced ethanol (35.8 ± 2.3g/l), glycerol (9.0 ± 0.2g/l), and arabitol (6.3 ± 0.2g/l). In the presence of xylose, the strain produced xylitol (38 ± 1.8g/l) and glycerol (18 ± 1.0g/l) as major metabolites. Diauxic growth was observed when the strain was grown with different combinations of glucose/xylose, and glucose was the preferred substrate. The presence of glucose enhanced the conversion of xylose to xylitol. By feeding a mixture of glucose at 100g/l and xylose at 100g/l, it was found that the strain produced a maximum of 72 ± 3g/l of xylitol. A study of important enzymes involved in the synthesis of xylitol (xylose reductase (XR) and xylitol dehydrogenase (XDH)), glycerol (glycerol-3-phosphate dehydrogenase (G3PDH)) and ethanol (alcohol dehydrogenase (ADH)) in cells grown in the presence of glucose and xylose revealed high specific activity of G3PDH and ADH in cells grown in the presence of glucose, whereas high specific activity of XR, XDH, and G3PDH was observed in cells grown in the presence of xylose. To our knowledge, this is the first study to elaborate the glucose and xylose metabolic pathway in this yeast strain.

Differential Response of the Catalase, Superoxide Dismutase and Glycerol-3-phosphate Dehydrogenase to Different Environmental Stresses in Debaryomyces nepalensis NCYC 3413

The effect of salt, pH, and temperature stress on the cellular level of antioxidant enzymes, catalase and superoxide dismutase (SOD) and glycerol-3-phosphate dehydrogenase (G3PDH) was studied in Debaryomyces nepalensis NCYC 3413, a halotolerant yeast. The catalase activity increased in different phases, while SOD and G3PDH activities declined in late stationary phase. A significant increase in SOD activity was observed under different stress as compared to control. Salt and temperature stress enhanced the catalase activity where as it was suppressed by pH stress. G3PDH level increased with salt stress, however, no significant change was observed under pH and temperature stress. The observations recorded in this investigation suggested that D. nepalensis has an efficient protective mechanism of antioxidant enzymes and G3PDH against salt, pH, and temperature stresses.

Quantitative evaluation of yeast's requirement for glycerol formation in very high ethanol performance fed-batch process

BackgroundGlycerol is the major by-product accounting for up to 5% of the carbon in Saccharomyces cerevisiae ethanolic fermentation. Decreasing glycerol formation may redirect part of the carbon toward ethanol production. However, abolishment of glycerol formation strongly affects yeast's robustness towards different types of stress occurring in an industrial process. In order to assess whether glycerol production can be reduced to a certain extent without jeopardising growth and stress tolerance, the yeast's capacity to synthesize glycerol was adjusted by fine-tuning the activity of the rate-controlling enzyme glycerol 3-phosphate dehydrogenase (GPDH). Two engineered strains whose specific GPDH activity was significantly reduced by two different degrees were comprehensively characterized in a previously developed Very High Ethanol Performance (VHEP) fed-batch process.ResultsThe prototrophic strain CEN.PK113-7D was chosen for decreasing glycerol formation capacity. The fine-tuned reduction of specific GPDH activity was achieved by replacing the native GPD1 promoter in the yeast genome by previously generated well-characterized TEF promoter mutant versions in a gpd2Δ background. Two TEF promoter mutant versions were selected for this study, resulting in a residual GPDH activity of 55 and 6%, respectively. The corresponding strains were referred to here as TEFmut7 and TEFmut2. The genetic modifications were accompanied to a strong reduction in glycerol yield on glucose; the level of reduction compared to the wild-type was 61% in TEFmut7 and 88% in TEFmut2. The overall ethanol production yield on glucose was improved from 0.43 g g-1 in the wild type to 0.44 g g-1 measured in TEFmut7 and 0.45 g g-1 in TEFmut2. Although maximal growth rate in the engineered strains was reduced by 20 and 30%, for TEFmut7 and TEFmut2 respectively, strains' ethanol stress robustness was hardly affected; i.e. values for final ethanol concentration (117 ± 4 g L-1), growth-inhibiting ethanol concentration (87 ± 3 g L-1) and volumetric ethanol productivity (2.1 ± 0.15 g l-1 h-1) measured in wild-type remained virtually unchanged in the engineered strains.ConclusionsThis work demonstrates the power of fine-tuned pathway engineering, particularly when a compromise has to be found between high product yield on one hand and acceptable growth, productivity and stress resistance on the other hand. Under the conditions used in this study (VHEP fed-batch), the two strains with "fine-tuned" GPD1 expression in a gpd2Δ background showed slightly better ethanol yield improvement than previously achieved with the single deletion strains gpd1Δ or gpd2Δ. Although glycerol reduction is known to be even higher in a gpd1Δ gpd2Δ double deletion strain, our strains could much better cope with process stress as reflected by better growth and viability.