Xanthohumol inhibits non-small cell lung cancer via directly targeting T-lymphokine-activated killer cell-originated protein kinase.

Xanthohumol is a principal prenylated chalcone isolated from hops. Previous studies have shown that xanthohumol was effective against various types of cancer, but the mechanisms, especially the direct targets for xanthohumol to exert an anticancer effect, remain elusive. Overexpression of T-lymphokine-activated killer cell-originated protein kinase (TOPK) promotes tumorigenesis, invasion and metastasis, implying the likely potential for targeting TOPK in cancer prevention and treatment. In the present study, we found that xanthohumol significantly inhibited the cell proliferation, migration and invasion of non-small cell lung cancer (NSCLC) in vitro and suppressed tumor growth in vivo, which is well correlated with inactivating TOPK, evidenced by reduced phosphorylation of TOPK and its downstream signaling histone H3 and Akt, and decreased its kinase activity. Moreover, molecular docking and biomolecular interaction analysis showed that xanthohumol was able to directly bind to the TOPK protein, suggesting that TOPK inactivation by xanthohumol is attributed to its ability to directly interact with TOPK. The findings of the present study identified TOPK as a direct target for xanthohumol to exert its anticancer activity, revealing novel insight into the mechanisms underlying the anticancer activity of xanthohumol.

Potential enzymes involved in beer monoterpenoids transformation: structures, functions and challenges.

Monoterpenes are important flavor and fragrance compounds in food. In beer, the monoterpenes mainly come from hops added during boiling process. Biotransformations of monoterpene which occurred during fermentation conferred beer with various kinds of aroma profiles, which can be mainly attributed to the contribution of enzymes in yeast. However, there are few reports on the identification and characterization of these enzymes in yeast. Illustrating the structure and functions of key enzymes related to transformations will broaden their potential applications in beer or other foodstuffs. Monoterpenoids including terpene hydrocarbons (limonene, myrcene, and pinene) and terpene alcohol (linalool, geraniol, nerol, and citronellol) gave the beer flower-like or fruit-like aroma. The biotransformation of monoterpenes and monoterpene alcohols in bacteria and yeast, and potential enzymes related to the transformation of them are reviewed here. Enzymes primarily are dehydrogenases including linalool dehydrogenase/isomerase, geraniol/geranial dehydrogenase, nerol dehydrogenase and citronellol dehydrogenase. Most of them are substrate-specific or substrate-specific after modifications by biotechnology methods, and part of them have been expressed in E. coli, while the purification and catalytic rate is very low. Efforts should be made to acquire abundant enzymes, and to fabricate enzyme-expressing yeast, which can be further applied in beer fermentation system.highlightsMonoterpenoids contributed to the flavor of food, especially beer.Transformation of monoterpenoids occurred during fermentation.Various kinds of enzymes are involved in the transformation of monoterpenoids in bacteria, yeast, etc.Crystal structures of these enzymes have been partially resolved.Few enzymes are further applied in food system to obtain abundant flavor.

Response of Saccharomyces cerevisiae var. diastaticus to nerol: Evaluation of antifungal potential by inhibitory effect and proteome analyses.

Saccharomyces cerevisiae var. diastaticus (S. diastaticus) is a major spoilage yeast in brewing. In the present research, the antifungal properties of nerol and the proteome response of S. diastaticus were studied. Results showed nerol can inhibit cell budding and delay yeast fermentation in a dose-depended manner. After 3 d of treatment with 0.25 mg·mL-1 nerol, intracellular ROS levels increased 1.66-fold (P < 0.01), and the cells with damaged membrane increased to 23.2 %. Quantitative proteomic profiles utilizing a capillary-HPLC-MS/MS technology revealed that proteins involved in the metabolism of fermentable sugars were up-regulated in S. diastaticus cells treated with nerol, indicating nerol treatment altered the metabolite pattern of fermentable sugars. Proteins associated with the cell membrane biogenesis, heat shock proteins, amino acid biosynthesis, and glutathione metabolism were similarly up-regulated. These findings revealed the mechanism of nerol-induced yeast cell damage as well as the detoxification response of yeast cells.

Characterization of bitter-tasting and antioxidant activity of dry-hopped beers.

BACKGROUND: Bitter flavors and antioxidant activities are critical characteristics and indicators, respectively, of beer quality. To gain a better understanding of dry-hopped beer's bitterness, this work comprehensively evaluated the perceived bitterness intensity and bitterness attributes from aspects of beer aroma and non-volatile bitter compounds using sensory analysis under two conditions: (i) with and (ii) without nose clips. To quantify bitter and volatile compounds, the work conducted chromatographic analyses: high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). Simultaneously, this work assessed the antioxidant activity of commercially dry-hopped beers. RESULTS: First, dry-hopped beer in this study contained abundant non-volatile bitter compounds (hop bitter acids, polyphenols and flavonoids), and aroma was validated using HPLC, UPLC-MS and GC-MS methods. Moreover, the bitter-tasting perception test findings demonstrated that many dry-hopped beers had a higher bitterness intensity when evaluated without a nose clip, whereas this phenomenon was adverse in several ale beers. Additionally, the 'lingering' and 'harsh' characteristics were diminished when beer aroma was blocked out (with nose clip) for dry-hopped beer. Meanwhile, most dry-hopped beers had greater antioxidant activity than ale beers (P < 0.05). CONCLUSION: This work revealed the bitterness complexity of dry-hopped beer; besides non-volatile bitter compounds, beer aroma had an impact on the perceived bitterness intensity and attributes, and dry-hopped beer had a relatively intense antioxidant capacity. This study facilitated the development of a detailed knowledge about the assessment of bitter-tasting perceptions in dry-hopped beers and provided a basis for the development of functional beer benefiting human health. © 2022 Society of Chemical Industry.

Exploring two types of prenylated bitter compounds from hop plant (Humulus lupulus L.) against α-glucosidase in vitro and in silico.

Hops are abundant in natural bioactive compounds. In this work, nine prenylated bitter compounds from hop were evaluated for their inhibitory activity against α-glucosidase. As a result, four flavonoids and one phloroglucinol (lupulone, LP) outperformed acarbose in inhibiting α-glucosidase. Isoxanthohumol (IX) and LP with two types of structures were selected for inhibition mechanism studies by spectroscopic methods and molecular dynamics simulation (MD). Results showed that IX acted as noncompetitive inhibitor and bound to α-glucosidase in allosteric sites via hydrogen bonds, hydrophobic, van der Waals (vdW), and electrostatic force, whereas LP was uncompetitive inhibitor and bound to catalytic sites via hydrophobic and vdW interactions. Notably, the conformation around binding site of α-glucosidase formed stable α-helix and tightened after binding IX and LP, respectively, which helped to elucidate noncompetitive and uncompetitive inhibitory mechanisms. This work demonstrated that two types of prenylated bitter compounds are discrepant in their mechanisms of interaction with α-glucosidase.

Key Enzymes Involved in the Synthesis of Hops Phytochemical Compounds: From Structure, Functions to Applications.

Humulus lupulus L. is an essential source of aroma compounds, hop bitter acids, and xanthohumol derivatives mainly exploited as flavourings in beer brewing and with demonstrated potential for the treatment of certain diseases. To acquire a comprehensive understanding of the biosynthesis of these compounds, the primary enzymes involved in the three major pathways of hops' phytochemical composition are herein critically summarized. Hops' phytochemical components impart bitterness, aroma, and antioxidant activity to beers. The biosynthesis pathways have been extensively studied and enzymes play essential roles in the processes. Here, we introduced the enzymes involved in the biosynthesis of hop bitter acids, monoterpenes and xanthohumol derivatives, including the branched-chain aminotransferase (BCAT), branched-chain keto-acid dehydrogenase (BCKDH), carboxyl CoA ligase (CCL), valerophenone synthase (VPS), prenyltransferase (PT), 1-deoxyxylulose-5-phosphate synthase (DXS), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR), Geranyl diphosphate synthase (GPPS), monoterpene synthase enzymes (MTS), cinnamate 4-hydroxylase (C4H), chalcone synthase (CHS_H1), chalcone isomerase (CHI)-like proteins (CHIL), and O-methyltransferase (OMT1). Furthermore, research advancements of each enzyme in terms of reaction conditions, substrate recognition, enzyme structures, and use in engineered microbes are described in depth. Hence, an extensive review of the key enzymes involved in the phytochemical compounds of hops will provide fundamentals for their applications in beer production.

Resveratrol metabolites ameliorate insulin resistance in HepG2 hepatocytes by modulating IRS-1/AMPK.

Resveratrol (trans-3,5,4'-trihydroxystilbene, RSV), a naturally occurring biologically active polyphenol has been observed to induce numerous beneficial effects in diabetic animals and humans. However, its protective effects are somewhat controversial due to low bioavailability and rapid clearance rate. Therefore, we in this study have tried to investigate if its main metabolites, RSV-3-O-glucuronide (R3G) and RSV-4-O-glucuronide (R4G) could ameliorate insulin resistance, similar to RSV in insulin-resistant HepG2 cells. Herein, we first established an insulin-resistant cell model by treating HepG2 cells with 1 × 10-6 mol L-1 insulin for 24 h. Subsequently, the effects of R3G and R4G on insulin resistance inhibition were evaluated in HepG2 cells. Interestingly, our data indicated that R3G and R4G treatment improved cellular glucose uptake and glycogen synthesis contents, and blocked generation of intracellular reactive oxygen species (ROS). Additionally, R3G and R4G also modulated insulin signaling and improved insulin sensitivity by modulating the IRS-1/AMPK signaling pathway. Taken together, our data provided a significant new insight into the effects and molecular mechanism of R3G and R4G on ameliorating insulin resistance in HepG2 cells. Overall, our data supported the hypothesis that despite low bioavailability in vivo, RSV biological effects could be mediated through its metabolites.

Chemical characteristics and antithrombotic effect of chondroitin sulfates from sturgeon skull and sturgeon backbone.

Chondroitin sulfates (CSs) were extracted from sturgeon skull and backbone, and their chemical composition, anticoagulant, anti-platelet and thrombolysis activities were evaluated. The average molecular weights of CS from sturgeon skull and backbone were 38.5kDa and 49.2kDa, respectively. Disaccharide analysis indicated that the sturgeon backbone CS was primarily composed of disaccharide monosulfated in position four of the GalNAc (37.8%) and disaccharide monosulfated in position six of the GalNAc (59.6%) while sturgeon skull CS was primarily composed of nonsulfated disaccharide (74.2%). Sturgeon backbone CS showed stronger antithrombotic effect than sturgeon skull CS. Sturgeon backbone CS could significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT), inhibited ADP-induced platelet aggregation and dissolved platelet plasma clots in vitro. The results suggested that sturgeon backbone CS can be explored as a functional food with antithrombotic function.

Zn(2+) rather than Ca(2+) or Mg(2+) used as a cofactor in non-muscular actin from the oyster to control protein polymerization.

BACKGROUND: The major cytoskeletal protein of most cells is actin, which polymerizes to form actin filaments (F-actin). Each actin monomer (G-actin) contains a divalent alkaline earth metal ion (in vivo Mg(2+); in vitro usually Ca(2+)) as a cofactor that is crucial for protein polymerization. Prior to this study, however, whether or not other types of metal ions can play the same role as Mg(2+) or Ca(2+) in actins remains unknown. METHODS: A new actin from the gills of oyster (AGO) was prepared and characterized by protein purification techniques, SDS- and native-PAGE, and LC-MS\MS for the first time. The property of this protein was studied by CD, fluorescence and UV/vis spectroscopy, laser light scattering, and TEM. RESULTS: AGO is a monomer with a MW of ~42kDa. AGO is unique among all known actins in that Zn(2+) is only a naturally binding metal in the protein, and that one native AGO molecule binds 8 zinc ions, which can be removed by EDTA treatment at pH7.2. The presence of zinc has a great effect on the secondary and tertiary structure of the protein. Correlated with such effect is that these zinc ions in native AGO facilitate protein polymerization, whereas removal of zinc ions from native AGO results in a loss of such polymerization property. CONCLUSIONS: The present work demonstrates that AGO is a novel zinc-binding protein with high capacity, and high selectivity. GENERAL SIGNIFICANCE: This work extends an understanding of the function of zinc and actin.

Zeranol induces cell proliferation and protein disulfide isomerase expression in mammary gland of ACI rat.

BACKGROUND: Zeranol is a non-steroidal anabolic growth promoter with potent estrogenic activity that is widely used as a growth promoter in the US beef industry. Consumption of beef derived from Zeranol-implanted cattle may be a risk factor for breast cancer. Protein disulfide isomerase (PDI) has been studied extensively as a key enzyme involving in the formation of the correct pattern of disulfide bonds in newly synthesized proteins. The relationship between PDI expression and cancer development has attracted interest of cancer researchers in recent years. MATERIALS AND METHODS: We implanted ACI rats with 12 mg Zeranol pellet and harvested the mammary tissues and tumor at day 110 after implantation and investigated the effect of Zeranol-implantation on cell proliferation by histological examination and proliferation in vitro. We also evaluated PDI mRNA expression in primary epithelial cells isolated from normal mammary glands and primary tumor cells from tumor specimens using real-time RT-PCR. To further confirm, we also evaluated the effect of Zeranol on PDI mRNA expression in primary epithelial cells isolated from normal mammary gland of ACI rats. RESULTS: We observed a palpable mammary tumor in one of three Zeranol-implanted ACI rats at day-110 post Zeranol-implantation. Zeranol-implantation significantly promoted the cell proliferation of primary mammary epithelial and stromal cells isolated from the mammary gland of normal ACI rats. PDI mRNA is over-expressed in primary tumor cells isolated from the tumor specimen and in Zeranol-treated primary cultured epithelial cells from the mammary gland of normal ACI rats. CONCLUSION: These findings suggest that up-regulated expression of PDI may play a critical role in mammary tumorigenesis and cell proliferation in response to Zeranol. Our findings implicate PDI as a biomarker for mammary tumorigenesis.

Physico-chemical characteristics and free fatty acid composition of dry fermented mutton sausages as affected by the use of various combinations of starter cultures and spices.

The microbiological, physico-chemical and free fatty acid composition of dry fermented mutton sausages were determined during ripening and storage. Three sausage mixtures (starter culture [SC], SC and black pepper [SC+BP] and SC, BP and cumin [SC+BP+C]) were compared with a control (CO). In general, the lactic acid bacteria populations in the SC+BP increased significantly to 9 log CFU/g and were higher than the CO (8 log CFU/g) (P<0.05) from fermentation to ripening. The pH values of the SC, SC+BP and SC+BP+C were 4.81, 4.55 and 4.53 respectively, significantly lower (P<0.05) than the CO at the end of fermentation. The water activity (a(w)) in all sausages decreased significantly to 0.88 at Day 7. The total free fatty acid (TFFA) in the treatments increased significantly (P<0.05) during ripening and storage. The levels of MUFA+PUFA/SFA in SC+BP and SC+BP+C at Day 7 were 2.44 and 2.31 respectively, higher than the control (1.65) (P>0.05).

Serum derived from zeranol-implanted ACI rats promotes the growth of human breast cancer cells in vitro.

BACKGROUND: Zeranol (Z) is a non-steroidal anabolic growth promoter with potent estrogenic activity that is widely used as a growth promoter in the US beef industry. Consumption of beef derived from zeranol-implanted cattle may be a risk factor for breast cancer. MATERIALS AND METHODS: The effect of serum on the proliferation of human breast cancer MCF-7 cell line and primary cultured human breast epithelial cells (PCHBECs) was investigated. ACI rats were implanted with 12 mg zeranol pellet and the serum was harvested at day 110 after implantation. The effect of zeranol-serum on mRNA expression of cell cycle regulating gene (cyclin D1) and tumor suppressor genes (p53, and p21) was evaluated using real-time RT-PCR. RESULTS: The serum derived from ACI rats 110 days post-zeranol implantation significantly promoted the proliferation of MCF-7 cells and primary cultured human breast epithelial cells compared to control serum. Zeranol-serum up-regulated cyclin D1 and down-regulated p53 and p21 expression in PCHBECs compared with control serum. CONCLUSION: Bio-active zeranol metabolites contained in meat produced from cattle after zeranol implantation may be a risk factor for breast cancer.

Antioxidant properties of peptide fractions from silver carp (Hypophthalmichthys molitrix) processing by-product protein hydrolysates evaluated by electron spin resonance spectrometry.

Silver carp processing by-product protein is usually discarded as an industrial solid waste. In this study the protein was recovered using a pH-shift method, after which seven commercial proteases were separately employed to prepare antioxidative hydrolysates. Among the hydrolysates, pepsin hydrolysates, which had the highest free radical-scavenging activity, were further separated into five peptide fractions, SCPH-I (>10kDa), SCPH-II (5-10kDa), SCPH-III (3-5kDa), SCPH-IV (1-3kDa), and SCPH-V (<1kDa), by using ultrafiltration. The antioxidative properties of the peptide fractions were investigated, using a free radical-scavenging assay, by electron spin resonance. The results show that SCPH-V had the highest scavenging effects on DPPH (1,1-diphenyl-2-picrylhydrazyl), hydroxyl and superoxide anion radicals. SCPH-V had potent antioxidant activity in the prevention of the peroxidation of linoleic acid and alleviation of H2O2-induced oxidative stress in human intestinal epithelial caco-2 cells. The results indicated that the antioxidant capacity of silver carp by-product hydrolysates could be enhanced by ultrafiltration.

Aromatase expression in leptin-pretreated human breast pre-adipocytes is enhanced by zeranol and suppressed by (-)-gossypol.

BACKGROUND: Obesity is associated with an increased risk of estrogen-dependent breast cancer. Recently, concerns have been raised regarding the role of zeranol (Z), a non-steroidal anabolic growth promoter with potent estrogenic activity widely used in the U.S.A. beef industry, as a possible contributor to an increased incidence of human breast cancer. This study hypothesized that obese individuals may be at greater risk of developing zeranol-induced breast cancer. MATERIALS AND METHODS: The aromatase mRNA expression level of three cell types isolated from adipose tissues were assayed by RT-PCR, and the cell proliferation of primary cultured human normal breast pre-adipocytes (HNBPADs) was investigated using the CellTiter96® non-radioactive method. The effects of Z and gossypol on aromatase expression of leptin-pretreated HNBPADs were evaluated by RT-PCR. RESULTS: HNBPADs expressed higher aromatase than primary cultured human breast epithelial cells and stromal cells. Z enhanced the mitogenic activity of leptin and increased aromatase expression in HNBPADs. Moreover, (-)-gossypol counteracted Z- and leptin-induced cell proliferation and aromatase expression. CONCLUSION: These results suggested that bioactive Z metabolites contained in meat produced from Z-implanted beef cattle may increase estrogen biosynthesis in obese individuals by increasing aromatase expression and estrogen production, which will promote cell sensitivity and increase breast cancer cell growth.

Lipids deposition, composition and oxidative stability of subcutaneous adipose tissue and Longissimus dorsi muscle in Guizhou mini-pig at different developmental stages.

The aim of this study was to investigate the effect of developmental stage on lipids deposition, composition and oxidative stability of subcutaneous adipose tissue (SAT) and Longissimus dorsi muscle (LDM) in Guizhou mini-pig. Pigs were raised in the same condition, and SAT and LDM were sampled on 90 d, 180 d and 270d. Lipids content decreased (P<0.01) from 90 d to 180 d and increased (P<0.01) from 180 d to 270 d in SAT and LDM. Neutral lipids in both tissues decreased (P<0.01) from 90 d to 180 d and increased (P<0.01) from 180 d to 270 d, while phospholipids content changed inversely during the three selected time points. Developmental times had great influence on fatty acids (FAs) composition of neutral lipids, phospholipids and free fatty acids (FFAs) except FAs composition of FFAs in SAT. Lipids oxidative stability in SAT and LDM both decreased between 90 d and 180 d (P<0.05) and increased by 270 d (P<0.05). In conclusion, due to the increased contents of unsaturated fatty acids and decreased oxidation stability, Guizhou or other mini-pigs slaughtered at an early age may have a negative effect on meat quality.

AMP-activated protein kinase signalling pathways are down regulated and skeletal muscle development impaired in fetuses of obese, over-nourished sheep.

Maternal obesity and over-nutrition give rise to both obstetric problems and neonatal morbidity. The objective of this study was to evaluate effects of maternal obesity and over-nutrition on signalling of the AMP-activated protein kinase (AMPK) pathway in fetal skeletal muscle in an obese pregnant sheep model. Non-pregnant ewes were assigned to a control group (Con, fed 100% of NRC nutrient recommendations, n = 7) or obesogenic group (OB, fed 150% of National Research Council (NRC) recommendations, n = 7) diet from 60 days before to 75 days after conception (term 150 days) when fetal semitendinosus skeletal muscle (St) was sampled. OB mothers developed severe obesity accompanied by higher maternal and fetal plasma glucose and insulin levels. In fetal St, activity of phosphoinositide-3 kinase (PI3K) associated with insulin receptor substrate-1 (IRS-1) was attenuated (P < 0.05), in agreement with the increased phophorylation of IRS-1 at serine 1011. Phosphorylation of AMP-activated protein kinase (AMPK) at Thr 172, acetyl-CoA carboxylase at Ser 79, tuberous sclerosis 2 at Thr 1462 and eukaryotic translation initiation factor 4E-binding protein 1 at Thr 37/46 were reduced in OB compared to Con fetal St. No difference in energy status (AMP/ATP ratio) was observed. The expression of protein phosphatase 2C was increased in OB compared to Con fetal St. Plasma tumour necrosis factor alpha (TNFalpha) was increased in OB fetuses indicating an increased inflammatory state. Expression of peroxisome proliferator-activated receptor gamma (PPARgamma) was higher in OB St, indicating enhanced adipogenesis. The glutathione: glutathione disulphide ratio was also lower, showing increased oxidative stress in OB fetal St. In summary, we have demonstrated decreased signalling of the AMPK system in skeletal muscle of fetuses of OB mothers, which may play a role in altered muscle development and development of insulin resistance in the offspring.

Isolation of cathepsin B from the muscle of silver carp (Hypophthalmichthys molitrix) and comparison of cathepsins B and L actions on surimi gel softening.

Cathepsin B from silver carp muscle was purified to 263-fold by acid treatment, ammonium sulfate fractionation, followed by a series of chromatographic separations. The molecular mass of the purified enzyme was 29kDa as determined by SDS-PAGE and immunoblotting. The purified enzyme was activated by dithiothreitol and cysteine while it was substantially inhibited by E-64, suggesting the purified enzyme belongs to the cysteine proteinase family. Optimal pH and temperature were 5.5 and 35°C, respectively. The enzyme catalyzed the hydrolysis of Z-Arg-Arg-MCA with a parameter of Km (90µM) and Kcat (20.3s(-1)), but hardly hydrolyzed Arg-MCA. Analysis of surimi gel strength and microstructure showed that cathepsins B and L were capable of destroying the network structure of silver carp surimi gels, consequently causing gel softening. Cathepsin L might play an important role in the modori effect.

Insulin-like growth factor-1 (IGF-1) and leucine activate pig myogenic satellite cells through mammalian target of rapamycin (mTOR) pathway.

Myogenic satellite cells are adult stem cells and have important roles in skeletal muscle growth, repair, and regeneration. Both insulin-like growth factor-1 (IGF-1) and leucine stimulate skeletal muscle growth, which link to the activation and proliferation of myogenic satellite cells in skeletal muscle. Mammalian target of rapamycin (mTOR) signaling is one of the main signaling pathways controlling protein synthesis and cell proliferation. Thus, IGF-1 and leucine may stimulate activation of myogenic satellite cells through mTOR signaling. In this study, myogenic satellite cells were isolated from 6-month-old pigs and subjected to IGF-1 and leucine treatments. Both IGF-1 and leucine upregulated mTOR signaling in myogenic satellite cells. The phosphorylation of mTOR at Ser(2448) increased 83.8 +/- 7.7% by IGF-1 (P < 0.05) and 83.4 +/- 5.7% by leucine (P < 0.05). The downstream targets of mTOR, S6 kinase, and 4E-binding protein 1 (4EBP1) were also phosphorylated due to IGF-1 and leucine treatments. Treatment with IGF-1 and leucine induced the phosphorylation of tuburin (TSC2), a key mediator upstream of mTOR signaling, by 272.8 +/- 26.4% and 94.2 +/- 28.7%, respectively. Treatment of cells with both IGF-1 and leucine did not show synergistic effect on mTOR signaling. Inhibition of mTOR by rapamycin abolished the protein synthesis and cell proliferation stimulated by both IGF-1 and leucine. In summary, our data showed that in preliminary cultured myogenic satellite cells mTOR signaling was activated due to IGF-1 and leucine treatments, and this mTOR activation is necessary for the activation of myogenic satellite cells.

Rat hindlimb unloading down-regulates insulin like growth factor-1 signaling and AMP-activated protein kinase, and leads to severe atrophy of the soleus muscle.

Inactivity is known to induce muscle atrophy, which is associated with insulin and insulin-like growth factor-1 (IGF-1) resistance, but the associated mechanisms remain poorly defined. The hindlimb unloading model has been used to reduce muscle activity. The objective of this study was to show the effect of hindlimb unloading on IGF-1 signaling and AMP-activated protein kinase (AMPK) activity in rat soleus and extensor digitorum longus (EDL) muscles. Twelve 7-week-old male Sprague-Dawley rats were assigned to 2 treatments: (i) rats without hindlimb unloading (Con) and (ii) rats with hindlimb unloading (Unload). After 2 weeks of treatment, the soleus and EDL muscles were dissected and used for biochemical analyses. Hindlimb unloading induced severe muscle atrophy in soleus muscle (0.122+/-0.007 g for Con vs. 0.031+/-0.004 g for Unload, p<0.01), but only slight atrophy in EDL muscle. The phosphorylation of AMPK (p<0.05) and its downstream substrate, acetyl-CoA carboxylase (ACC) (p<0.01) were reduced in soleus muscle due to unloading. The concentration of insulin receptor substrate-1 (IRS-1) and phosphorylation of IRS-1 at Ser636-639 and Ser789 were also reduced. Downstream IGF-1 signaling was downregulated in Unload rats. A reduction in IGF-1 concentration in unloaded soleus muscle was also observed. A slight reduction in AMPK activity and IGF-1 signaling were observed in EDL muscle. Since AMPK controls the sensitivity of IGF-1 signaling through phosphorylation at Ser789, the reduction in AMPK activity is expected to reduce the response of downstream IGF-1 signaling to IGF-1; this, in combination with reduced IGF-1 concentration, might be responsible for the severe muscle atrophy observed in unloaded soleus muscle.

[Quality analysis of Chinese bacon with near infrared spectroscopy].

The feasibility of fast and correctly detecting the quality of Chinese bacon by NIR was studied. The acid value (AV) can reflect the quality of Chinese bacon during processing and storage which is prescribed in the Chinese national standard methods definitely. The fat is abundant in Chinese bacon, so the AV index is important for the quality of Bacon. Samples were scanned on the Bruker FTNIR reflected spectra instrument after being ground. The preprocess method of Additional Scattered Correction was used for the mathematic model of AV and moisture content of Chinese Bacon by PLS. The correlation ratio and the RMSCV of AV and moisture content of the prediction set were 0. 98, 0. 25, 0. 90 and 0. 02 respectively. The results showed that NIR spectroscopy analysis technology can be used for fast detecting AV and moisture content of Chinese Bacon.