Glycolytic Potential Research Articles

Dissimilar regulation of glucose and lipid metabolism by leptin in two strains of gibel carp (Carassius gibelio).

Previous nutritional studies have shown that insulin regulation is different between DT and A strains of gibel carp. As leptin plays a pivotal role in the effects of insulin, we hypothesised that leptin regulation of glucose and lipid metabolism would differ between the two strains. To test our hypothesis, recombinant human leptin was injected into two strains. The results showed that leptin activated the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT), AMP-activated protein kinase-acetyl coenzyme A carboxylase and Janus kinase 2 (JAK2)-signal transducer and activator of transcription (STAT) signalling pathways in both strains. Hypoglycaemia induced by leptin might be due to higher glucose uptake by the liver and muscles together with enhanced glycolytic potential and reduced gluconeogenic potential. Decreased lipogenesis and up-regulated fatty acid oxidation were induced by leptin. In terms of genotype, the PI3K-AKT signalling pathway was more strongly activated by leptin in the muscle tissue of the A strain, as reflected by the heightened phosphorylation of AKT. Furthermore, glycogen content, glycolytic enzyme activity and gluconeogenic capability were higher in the A strain than the DT strain. Strain A had higher levels of fatty acid synthesis and lipolytic capacity in the liver than the DT strain, but the opposite was true in white muscle. Regarding leptin-genotype interactions, the DT strain displayed stronger regulation of glucose metabolism in the liver by leptin as compared with the A strain. Moreover, a more active JAK2-STAT signalling pathway accompanied by enhanced inhibition of fatty acid synthesis by leptin was observed in the DT strain. Overall, the regulation of glucose and lipid metabolism by leptin differed between the two strains, as expected.

Dietary cinnamaldehyde supplementation improves the growth performance, oxidative stability, immune function, and meat quality in finishing pigs

The objective of this study was to evaluate the effects of different concentrations of cinnamaldehyde in feed on growth performance, oxidative stability, immune function, and meat quality in finishing pigs. Sixty pigs (Duroc × Landrace × Yorkshire; body weight = 70.10 ± 3.01 kg) were used in this study. The pigs were randomly allotted to three treatments (four replicates (pens) with five pigs per pen), control diet (basal diet), basal diet + 40 mg cinnamaldehyde and basal diet + 80 mg cinnamaldehyde per kg of feed. The results showed that dietary cinnamaldehyde increased pigs’ average daily gain(ADG), M. longissimus dorsi area(LA), pH24h, water maintain rate and serum interleukin 2 (IL-2)content (P <0.05), and decreased average backfat thickness, shear force, intramuscular fat, marbling Score, glycolytic potential (P <0.05). Cinnamaldehyde significantly increased glutathione peroxidase (GSH-Px) (P <0.05), while malondialdehyde (MDA) content and superoxide dismutase (SOD) enzyme activity decreased (P <0.05). In addition, cinnamaldehyde decreased the activities of glycolytic enzymes phosphoglycerate kinase (PGK) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) (P <0.05).These results demonstrated that dietary cinnamaldehyde could improve growth performance and ameliorate meat quality of finishing pigs by improving the living immunity, enhancing antioxidant capacity, and reducing glycolytic capacity of meat.

Exploring the lncRNAs Related to Skeletal Muscle Fiber Types and Meat Quality Traits in Pigs.

The alteration in skeletal muscle fiber is a critical factor affecting livestock meat quality traits and human metabolic diseases. Long non-coding RNAs (lncRNAs) are a diverse class of non-coding RNAs with a length of more than 200 nucleotides. However, the mechanisms underlying the regulation of lncRNAs in skeletal muscle fibers remain elusive. To understand the genetic basis of lncRNA-regulated skeletal muscle fiber development, we performed a transcriptome analysis to identify the key lncRNAs affecting skeletal muscle fiber and meat quality traits on a pig model. We generated the lncRNA expression profiles of fast-twitch Biceps femoris (Bf) and slow-twitch Soleus (Sol) muscles and identified the differentially expressed (DE) lncRNAs using RNA-seq and performed bioinformatics analyses. This allowed us to identify 4581 lncRNA genes among six RNA libraries and 92 DE lncRNAs between Bf and Sol which are the key candidates for the conversion of skeletal muscle fiber types. Moreover, we detected the expression patterns of lncRNA MSTRG.42019 in different tissues and skeletal muscles of various development stages. In addition, we performed a correlation analyses between the expression of DE lncRNA MSTRG.42019 and meat quality traits. Notably, we found that DE lncRNA MSTRG.42019 was highly expressed in skeletal muscle and its expression was significantly higher in Sol than in Bf, with a positive correlation with the expression of Myosin heavy chain 7 (MYH7) (r = 0.6597, p = 0.0016) and a negative correlation with meat quality traits glycolytic potential (r = −0.5447, p = 0.0130), as well as drip loss (r = −0.5085, p = 0.0221). Moreover, we constructed the lncRNA MSTRG.42019–mRNAs regulatory network for a better understanding of a possible mechanism regulating skeletal muscle fiber formation. Our data provide the groundwork for studying the lncRNA regulatory mechanisms of skeletal muscle fiber conversion, and given the importance of skeletal muscle fiber types in muscle-related diseases, our data may provide insight into the treatment of muscular diseases in humans.

Exploring the Factors Contributing to the High Ultimate pH of Broiler Pectoralis Major Muscles Affected by Wooden Breast Condition.

The elevated ultimate pH (pHu) found in wooden breast (WB) meat suggests an altered muscular energetic status in WB but also could be related to a prematurely terminated post-mortem pH decline. The aims of this study were to explore the factors contributing to the elevated pHu and establish whether the occurrence of WB defect alters muscle post-mortem carbohydrate metabolism and determine if the contractile apparatus reflects such changes. A total of 24 carcasses from Ross 308 male chickens were obtained from a commercial producer and harvested using commercial processing procedures. Carcasses were categorized into unaffected (NORM) and WB groups (n = 12 each), and samples were collected from cranial bone-in pectoralis major (PM) muscles at 15 min and 24 h post-mortem for the determination of pH, glycolytic metabolites, adenonucleotides, buffering capacity, phosphofructokinase (PFK) activity, and in vitro pH decline. Twenty-four additional deboned PM samples (12 NORM and 12 WB) were collected from the same processing plant to assess muscle histology and sarcomere length at four different locations throughout the PM muscle. Data show that the reduced glycolytic potential of WB muscles only partially explains the higher (P < 0.001) pHu of WB meat, as residual glycogen along with unaltered PFK activity suggests that neither glycogen nor a deficiency of PFK is responsible for arresting glycolysis prematurely. The dramatic reduction in ATP concentrations in the early post-mortem period suggests a defective ATP-generating pathway that might be responsible for the reduced pH decline in WB samples. Further, the addition of excess of ATPase extended post-mortem glycolysis of WB meat in an in vitro glycolytic system. WB-affected samples have longer (P < 0.001) sarcomeres compared to NORM, indicating the existence of compromised energy-generating pathways in myopathic muscles that may have had consequences on the muscle contraction and tension development, as in vivo, also during the post-mortem period. Considering the overall reduced glycolytic potential and the myodegenerative processes associated with WB condition, we speculate that the higher pHu of WB meat might be the outcome of a drastically impaired energy-generating pathway combined with a deficiency and/or a dysfunction of muscle ATPases, having consequences also on muscle fiber contraction degree.

Quadrella incana (Capparaceae) Leaf Extract Enhances Proliferation and Maintenance of Neural Stem/Progenitor Cells through Upregulating Glycolytic Flux and Redox Potential.

Neural stem/progenitor cells (NSPCs) are self-renewing, multipotent cells located in the embryonic and adult central nervous system (CNS). Extensive preclinical and clinical studies have shed light on the potential of stem cell replacement therapy for various neurodegenerative diseases. The key prerequisite for the success of these clinical applications is the procurement of a sufficient number of high-quality NSPCs. In this study, we explored the biological activity of Quadrella incana leaf in NSPC homeostasis. We showed that the leaf extract of Quadrella incana upregulated NSPC marker and proliferative potential. On the other hand, Quadrella incana leaf suppressed spontaneous unintended NSPC differentiation. Mechanistically, Quadrella incana leaf contributed to the maintenance of NSPCs by upregulating glycolytic flux and redox potential.

Application of extended feed withdrawal time preslaughter and its effects on animal welfare and carcass and meat quality of enriched-housed pigs

A total of 144 barrows were distributed into four treatment groups. One group was housed conventionally and fasted for 16 h preslaughter, while the other three groups were housed in enriched conditions (straw-bedding and low density) and fasted for 16, 24 and 32 h preslaughter. When compared with conventionally-housed pigs, enriched-housed pigs were heavier (P < .05) and fatter (P < .01), but easier to handle at loading (P < .05) and produced less exudative pork (P < .05) possibly resulting from a lower post-mortem muscle glycolytic potential (P = .10). Extending fasting time up to 32 h reduced dressing yield (P < .001) and increased skin lesion scores (P < .01), but did not result in any clear or major effect on muscle metabolism and meat quality. In conclusion, given the beneficial effects of enriched housing conditions on stress response and pork quality, the application of an extended fasting time (32h) preslaughter is not required for this production.

The rearing system modulates biochemical and histological differences in loin and ham muscles between Basque and Large White pigs

Conventional pork production, based on highly selected breeds for growth efficiency and carcass leanness, is generally considered to decrease pork quality. In contrast, non-selected breeds produced in extensive systems are associated with high pork quality, which is generally attributed to higher intramuscular fat (IMF) content and less glycolytic muscle metabolism. The present study aimed to determine biochemical, histological and quality traits of loin and ham muscles of pigs from selected Large White (LW) and local French, non-selected Basque (B) breeds. Pigs were reared in a conventional indoor (C, slatted floor), alternative (A, indoor bedding and outdoor area) or extensive system (E, free range, B pigs only). A total of 100 castrated males were produced in 2 replicates, each containing 5 groups of 10 pigs based on breed and system: LWC, LWA, BC, BA and BE. The glycolytic longissimus muscle (LM) and semimembranosus muscle (SM), and the deep red (RSTM) and superficial white (WSTM) portions of semitendinosus muscle (STM) were studied at 145 kg BW. Overall, breed induced stronger effects on muscle traits than the rearing system, among which the E system induced greater changes. The lower muscle growth of B pigs was associated with fewer muscle fibers and a smaller cross-sectional area (CSA) of glycolytic fibers (P < 0.01). The SM was less glycolytic and more oxidative in B than in LW pigs (P < 0.001). The WSTM followed a similar trend, with a larger relative area of type I fibers in B pigs. In contrast, the LM and RSTM were more oxidative in LW pigs. B pigs had higher IMF content and ultimate pH in all muscles, along with lower glycolytic potential, less light and redder meat in the LM and SM (P < 0.001). Compared to the C system, the A system induced only a shift towards a more oxidative metabolism in the LM and a smaller fiber CSA in the RSTM of LW pigs (P < 0.05), without influencing pork quality traits. Compared to BC pigs, BE pigs had a more oxidative and less glycolytic muscle metabolism, along with higher ultimate pH, lower lightness and redder meat (P < 0.01), but similar IMF content. Overall, results indicate that influences of breed and rearing system on muscle properties depend on muscle type, and that IMF content and fiber-type composition are unrelated traits that can be modified independently by genetic or rearing factors.

A review of factors affecting goat meat quality and mitigating strategies

Abstract Goat meat is increasing in popularity worldwide due to a growing demand for lean and nutritious meat. It is important to have an understanding of factors affecting goat meat quality in order to ensure the best possible quality acceptable to consumers. This paper reviews current knowledge on key factors and strategies for improving goat meat quality. Among animal factors, the breed/genetics and age at slaughter are key to goat meat quality. Conditioning of goats destined for slaughter can improve the quality of meat through more desirable carcass fat content. It has been established that goat carcasses have low glycolytic potential and consequently yield higher pH meat, therefore, minimising ante-mortem stress is important for goat meat quality. Goat carcasses are very small and lean, therefore, chilling conditions should be carefully monitored in order to minimise the risk of cold shortening. Electrical stimulation of carcasses has been reported to improve goat meat tenderness. Pelvic suspension of goat carcasses may result in improved meat tenderness compared to Achilles-hung carcasses. Post-slaughter ageing can further improve the tenderness of goat meat. Several efforts have been made to address the concerns pertaining to goat meat quality, but the challenge now is to promote the consumption of goat meat among diverse consumers and establish it as a dietetically acceptable red meat source.

Impact of Two Levels of Low Voltage Electrical Stimulation on Beef Quality

ObjectivesElectrical stimulation (ES) prior to rigor mortis accelerates postmortem glycolysis, resulting in rapid postmortem depletion of glycogen and can partially simulate the physiological conditions created by stress. The objective of this study was to evaluate the influence of two levels of high voltage electrical stimulation on incidence of dark cutters, temperature decline, muscle pH, glycolytic potential, and meat quality.Materials and MethodsFifty beef carcasses were chosen at 3 collection times over 7 h; 14 at collection 1, 18 at collection 2, and 18 at collection 3. One side of each carcass received either 40 (E40) or 80 (E80) volts of ES. The paired side of each carcass served as a control and did not receive ES (C40 or C80). Temperature data loggers were placed into the sirloin of both sides of the first 4 carcasses from each collection period to monitor temperature decline. Muscle pH was measured on the longissimus muscle at 1, 12, 24, and 72 h postmortem. Steaks were fabricated from the longissimus lumborum for determination of WBSF, cook loss, glycolytic potential (GP), and objective color. Data were analyzed using PROC Mixed of SAS with fixed effect of treatment and random effect of carcass. Analysis of carcass temperature decline was conducted with control carcasses pooled to one treatment to better evaluate the effect of ES on temperature decline. Temperature data, WBSF, and pH were considered repeated measures. Significance was determined at P &lt; 0.05.ResultsNo dark cutting carcasses were observed in this study. A time by treatment interaction was observed for carcass temperature decline (P &lt; 0.001) where ES sides stayed warmer for longer than control sides. A treatment by time interaction was observed for pH decline (P &lt; 0.001) with C40 sides having an increased pH at 1 h postmortem compared to E80 sides. Carcass characteristics did not differ among treatments (P &gt; 0.05). A treatment effect was observed for WBSF values (P = 0.006) with ES sides being more tender than C40 sides. A day effect was observed (P = 0.009) with steaks aged for 7 d being less tender than steaks aged for 14 d (P = 0.007). Cook loss did not differ among treatments (P &gt; 0.05). A difference in cook loss by aging period (P = 0.014) was observed. Steaks aged for 3 d had less cook loss than steaks aged for 7 d (17.3% vs. 18.8% respectively; (P = 0.017) and tended to have less cook loss than steaks aged for 14 d (18.3%; P = 0.065). Glucose, lactate, and overall GP measurements did not differ among treatments (P &gt; 0.05). Objective L* values for E80 sides were greater than C40 (P = 0.0009) and C80 (P &lt; 0.0001), and E40 values were greater than C40 (P &lt; 0.0001). Objective a* values for E80 sides were greater than C40 (P = 0.002) and C80 (P = 0.035), and E40 values were greater than C40 (P &lt; 0.0001). Objective b* values were greater for E80 than C80 (P = 0.005) and C40 (P = 0.001), and E40 was greater than C40 (P &lt; 0.0001).ConclusionThese data suggest ES does not influence the incidence of dark cutters. However, utilization of an ES system can improve tenderness of steaks in addition to producing brighter, more red beef products. The results of this study indicate that similar quality characteristics can be obtained using 40 or 80 V of ES. Therefore, beef packing plants applying ES to carcasses may be able to reduce voltage without sacrificing quality.

MiR-489-3p/SIX1 Axis Regulates Melanoma Proliferation and Glycolytic Potential

Sine oculis homeobox 1 (SIX1), a key transcription factor for regulating aerobic glycolysis, participates in the occurrence of various cancer types. However, the role of SIX1 in melanoma and the upstream regulating mechanisms of SIX1 remain to be further investigated. MicroRNAs (miRNAs) have emerged as key regulators in tumorigenesis and progression. Here, we show that miR-489-3p suppresses SIX1 expression by directly targeting its 3′ untranslated region (3′ UTR) in melanoma cells. miR-489-3p suppressed melanoma cell proliferation, migration, and invasion through inhibition of SIX1. Mechanistically, by targeting SIX1, miR-489-3p dampens glycolysis, with decreased glucose uptake, lactate production, ATP generation, and extracellular acidification rate (ECAR), as well as an increased oxygen consumption rate (OCR). Importantly, glycolysis regulated by the miR-489-3p/SIX1 axis is critical for its regulation of melanoma growth and metastasis both in vitro and in vivo. In melanoma patients, miR-489-3p expression is negatively correlated with SIX1 expression. In addition, patients who had increased glucose uptake in tumors and with metastasis assessed by positron emission tomography (PET) scans showed decreased miR-489-3p expression and increased expression of SIX1. Collectively, our study demonstrates the importance of the miR-489-3p/SIX1 axis in melanoma, which can be a potential and a promising therapeutic target in melanoma.

Every-Other-Day Feeding Decreases Glycolytic and Mitochondrial Energy-Producing Potentials in the Brain and Liver of Young Mice.

Intermittent fasting is used to reduce body mass in obese adult humans and animals. However, information on the impact of one type of intermittent fasting (IF) called every-other-day feeding (EODF) on young animals is scarce. In this study, 1-month-old mice of both sexes were subjected to a 4-week regimen of EODF using age-matched counterparts fed ad libitum as controls. At the end of EODF exposure, experimental male and female mice weighed 14 and 13% less than the control counterparts. The EODF regimen resulted in lower liver levels of glycogen, glucose, and lactate, but did not affect lactate level in mouse cerebral cortex of both sexes. Activities of key glycolytic enzymes (hexokinase, phosphofructokinase, and pyruvate kinase) in liver of experimental mice were lower than those in controls. In the cerebral cortex, only hexokinase and pyruvate kinase activities were lower than in controls, but phosphofructokinase activity was not affected in IF females and was higher in IF males as compared with ad libitum fed males. Mitochondria isolated from liver of IF mice had lower respiratory control ratios, but those from the cortex had the same values as control animals. The concentration of β-hydroxybutyrate and the activity of β-hydroxybutyrate dehydrogenase were lower in the IF mouse liver, but not changed or enhanced in the IF cerebral cortex. Thus, animal responses to IF do not depend significantly on sex and are directed to decrease energy metabolism to save resources, and the effects are more pronounced in the liver than in the brain.

Combination of dietary glycaemic index and fasting time prior to slaughter as strategy to modify quality of pork

This study evaluates the effect of the dietary glycaemic index (low: L-GI vs. high: H-GI), pre-slaughter fasting times (17 h: f17 vs. 19 h: f19 vs. 22 h: f22), and their interaction, on certain meat quality characteristics. Greater duration of fasting resulted in lesser drip loss of muscle, greater LIPE expression (lipolysis) and 10% greater TBARS, with PUFA being the main source of free-fatty acid production. L-GI diets produced a greater drip loss, lipolytic activity and lesser C18:1n-9 relative mobilization, suggesting this group had greater glycolytic potential than H-GI. An interaction was found in meat characteristics related to fat metabolism. The IRS2 gene expression was greater in pigs fed L-GI diets, but only in a low fasting period. LIPE gene expression was greater for L-GI-f17 group than for L-GI-f22. Lesser n-6 PUFA but greater MUFA were found in the free fatty acid fraction of L-GI- f17 group thus resulting in a faster lipolysis initiation in this group.

The effect of dietary garcinol supplementation on oxidative stability, muscle postmortem glycolysis and meat quality in pigs

The objective of this study was to evaluate the effects of dietary garcinol (0, 200, 400 and 600 mg/kg) on the growth performance, meat quality, postmortem glycolysis and antioxidative capacity of finishing pigs. Dietary garcinol increased pigs' average daily gain, pH 24h, a* and myoglobin content of longissimus dorsi (LM) (P < 0.05), and decreased feed/gain ratio, the L*24h, glycolytic potential, drip loss, shear force, and backfat depth (P < 0.05). The glutathione peroxidase (GPx), catalase (CAT) and total antioxidative capacity (T-AOC) were significantly increased by garcinol (P < 0.05), while the activity of lactate dehydrogenase (LDH) and malonaldehyde (MDA) content were decreased (P < 0.05). Moreover, garcinol decreased the p300/CBP-associated factor (PCAF) activity, the acetylation level and activities of glycolysis enzymes phosphoglycerate kinase 1 (PGK1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase-3 (PFKFB3) (P < 0.05). The results of this study showed that garcinol decreased postmortem glycolysis, and this may be due to the mechanism of decreasing glycolytic enzyme acetylation induced by PCAF. The present study indicates that garcinol can facilitate the growth performance of pigs and improve pork quality by changing postmortem glycolysis and antioxidative capacity.

Association between meat color of DFD beef and other quality attributes

This study investigated the association between DFD beef color and other quality traits and explained the possible mechanisms. Beef longissimus thoracis (LT) was assessed and classified into one of three groups based on the pH 24 h post-mortem: normal (pH ≤ 5.70), atypical DFD (5.70 < pH ≤ 6.09) and typical DFD (pH > 6.09) beef and stored at 4 °C for 7 days. Typical DFD beef showed the lowest glycolytic potential, L*, a*, b*, chroma and oxymyoglobin accompanied with the highest water-holding capacity, hue angle and deoxymyoglobin values on day 1 of storage. Glycolytic potential was positively correlated with chroma, R630/580 and oxymyoglobin but was negatively correlated with pH and hue angle. Water-holding capacity was directly related to deoxymyoglobin levels. Atypical DFD beef showed a higher shear force value that was positively associated with metmyoglobin levels. In conclusion, DFD beef color was not only affected by ultimate pH but also related to shear force, glycolytic potential and water-holding capacity.

Relationship between water transparency and walleye (Sander vitreus) muscle glycolytic potential in northwestern Ontario lakes

Piscivorous predators at the apex of aquatic food webs are thought to exhibit foraging behaviours that depend on environmental conditions. Walleye (Sander vitreus), for example, is a freshwater predator that is most active under low light conditions. This study examined walleye resource use and swimming activity across lakes located in northwestern Ontario representing a gradient of water transparency. Muscle glycolytic potential, an index of swimming activity, was estimated by the activity of the enzyme lactate dehydrogenase (LDH). We show that walleye white muscle LDH activity increased with lake water transparency, but that this relationship is not determined by the use of nearshore resources, estimated from δ13C stable isotope signatures, or by prey abundance. On the other hand, walleye muscle LDH activity decreased with increasing prey size, and prey size was larger in lakes of low water transparency. These results support a positive relationship between water transparency and swimming activity in walleye, with prey size as an important factor contributing to this effect.

Attenuating effects of guanidinoacetic acid on preslaughter transport-induced muscle energy expenditure and rapid glycolysis of broilers

This study evaluated the effects of dietary guanidinoacetic acid (GAA) supplementation on growth performance, plasma variables, muscle energy status, glycolytic potential, and meat quality of broilers experiencing transport stress during the summer. A total of 320 28-day-old male Arbor Acres broilers were randomly allotted to 3 dietary treatments, including a GAA-free basal control diet (160 birds) and basal diet supplementation with 600 (80 birds) or 1,200mg/kg (80 birds) GAA for 14 D. On the morning of day 42, after an 8-h fast, the birds fed basal diets were divided into 2 equal groups, and all birds in the 4 groups of 80 birds were transported according to the following protocols: 1) a 0.5-h transport of birds on basal diets (as a lower-stress control group), 2) a 3-h transport of birds on basal diets, and a 3-h transport of birds on basal diets supplemented with either 3) 600 or 4) 1,200mg/kg GAA. The results revealed that dietary supplementation with GAA at 600 and 1,200mg/kg for 14 D prior to slaughter did not affect growth performance, carcass traits, and most textural characteristics and chemical composition of the pectoralis major (PM) muscle (P > 0.05). In the GAA-free group, a 3-h transport increased the broiler live weight loss, elevated the plasma corticosterone concentration, decreased the plasma glucose concentration, muscle concentrations of ATP, creatine and energy charge value, increased the muscle AMP concentration and AMP/ATP ratio, and accelerated glycolysis metabolism, which resulted in inferior meat quality (lower pH and higher drip loss, P < 0.05). However, dietary addition of GAA at 1,200mg/kg increased the mRNA expression of S-adenosyl-l-methionine: N-guanidino-acetate methyltransferase in the liver and creatine transporter in both the liver and PM muscle. It also elevated muscle concentrations of creatine and phosphocreatine (P < 0.05), which helps improve meat quality by ameliorating the 3-h transport-induced muscle energy expenditure and delaying anaerobic glycolysis of broilers.

Abstract 794: Inhibition of mitochondrial metabolism by a novel agent targeting RUNX2-DNA binding in breast cancer

Abstract The RUNX2 transcription factor promotes breast cancer growth and metastasis through interactions with a variety of cofactors that activate or repress target genes. RUNX2 knockdown decreases expression levels of glycolytic genes such as LDHA, HK2 and GLUT-1, but upregulates PDHA1 mRNA level and enzymatic activity, which is consistent with lower glycolytic potential. Using a direct computer-assisted drug discovery (CADD) approach, we identified CADD522 as a small molecule that inhibits the RUNX2-DNA binding, transcriptional activity of RUNX2, and expression of RUNX2 target genes. We also observed that CADD522 inhibits breast cancer growth and metastasis using in vitro and in vivo tumor models. RUNX2-activated glucose utilization and GLUT-1 levels were also reduced by CADD522. New data also define CADD522 as a potential antitumor agent that downregulates the levels of metabolites in the TCA cycle and inhibits mitochondrial oxygen consumption rates. Our results support the observations that CADD522 could regulate cellular metabolism through modulation of both glycolytic metabolism and mitochondrial oxidative phosphorylation. To address the mechanisms by which CADD522 exerts its inhibitory effects on mitochondrial metabolism, we performed RNA-Sequencing analysis in breast cancer cells and identified several specific molecular signatures that determine cellular response to RUNX2 and CADD522. Further pathway changes in mitochondrial function as well as validation of differentially expressed genes that play critical roles in mitochondrial metabolism are under investigation. Citation Format: Myoung Sook Kim, Ramkishore Gernapudi, Yessenia C. Cedeno, Brian M. Polster, Geoffrey D. Girnun, Antonino Passaniti. Inhibition of mitochondrial metabolism by a novel agent targeting RUNX2-DNA binding in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 794.

Early differential gene expression in beef Longissimus thoracis muscles from carcasses with normal (5.9) ultimate pH

The objective of this study was to investigate early postmortem (0.5 h) gene expression in beef Longissimus thoracis (LT) muscles from carcasses with NORMAL (<5.8) and HIGH (>5.9) ultimate pH (pHu). A total of 53 transcripts were differentially expressed (P-value <.05): 40 showed up-regulation and 13 showed down-regulation in HIGH pHu carcasses. Four up-regulated (PDK4, GADD45B, MAOA, METTL21C) genes were confirmed (P < .05) by q-PCR. HIGH pHu samples resulted with lower values in glycolytic potential and AMP-activated protein kinase activity compared to NORMAL at 0.5 and 24 h postmortem (P < .05). Functional pathway analysis showed that calcium transport and GADD45 signaling pathways are associated with the development of HIGH pH meat. Genes involved in stress-related signaling, such as GADD45B, METTL21C and MAOA were overexpressed. These genes are involved in stress signaling that might be affecting Ca2+ transport and oxidative metabolism pathways in HIGH pH muscles.

Depletion of dAKAP1–protein kinase A signaling islands from the outer mitochondrial membrane alters breast cancer cell metabolism and motility

Breast cancer screening and new precision therapies have led to improved patient outcomes. Yet, a positive prognosis is less certain when primary tumors metastasize. Metastasis requires a coordinated program of cellular changes that promote increased survival, migration, and energy consumption. These pathways converge on mitochondrial function, where distinct signaling networks of kinases, phosphatases, and metabolic enzymes regulate these processes. The protein kinase A-anchoring protein dAKAP1 compartmentalizes protein kinase A (PKA) and other signaling enzymes at the outer mitochondrial membrane and thereby controls mitochondrial function and dynamics. Modulation of these processes occurs in part through regulation of dynamin-related protein 1 (Drp1). Here, we report an inverse relationship between the expression of dAKAP1 and mesenchymal markers in breast cancer. Molecular, cellular, and in silico analyses of breast cancer cell lines confirmed that dAKAP1 depletion is associated with impaired mitochondrial function and dynamics, as well as with increased glycolytic potential and invasiveness. Furthermore, disruption of dAKAP1-PKA complexes affected cell motility and mitochondrial movement toward the leading edge in invasive breast cancer cells. We therefore propose that depletion of dAKAP1-PKA "signaling islands" from the outer mitochondrial membrane augments progression toward metastatic breast cancer.

Planctomycetes in boreal and subarctic wetlands: diversity patterns and potential ecological functions.

Members of the phylum Planctomycetes are common inhabitants of boreal Sphagnum peat bogs and lichen-dominated tundra wetlands. These bacteria colonize both oxic and anoxic peat layers and reach the population size of 107 cells per gram of wet peat. The 16S rRNA gene sequences from planctomycetes comprise 5%-22% of total 16S rRNA gene reads retrieved from peat samples. Most abundant peat-inhabiting planctomycetes affiliate with the families Isosphaeraceae and Gemmataceae, and with as-yet-uncultured Phycisphaera-related group WD2101. The use of metatranscriptomics to assess the functional role of planctomycetes in peatlands suggested the presence of versatile hydrolytic capabilities in these bacteria. This evidence was further confirmed by the analysis of genome-encoded capabilities of isolates from wetlands. Large (up to 12 Mbp) genomes of planctomycetes encode wide repertoires of carbohydrate-active enzymes including many unclassified putative glycoside hydrolases, which suggests the presence of extremely high glycolytic potential in these bacteria. Experimental tests confirmed their ability to grow on xylan, pectin, starch, lichenan, cellulose, chitin and polysaccharides of microbial origin. These results provide an insight into the ecological roles of peat-inhabiting planctomycetes and suggest their participation in degradation of plant-derived polymers, exoskeletons of peat-inhabiting arthropods as well as exopolysaccharides produced by other bacteria.