Lipid metabolism, immune and apoptosis transcriptomic responses of the hepatopancreas of Chinese mitten crab to the exposure to microcystin-LR.

Global warming is favouring the incidence, intensity and duration of harmful cyanobacterial blooms. Microcystin-LR (MC-LR), a hepatotoxic agent, is produced during cyanobacterial blooms. To understand the molecular mechanisms of acute hepatotoxic effect of low doses of MC-LR in crab, we examined differentially expressed genes in samples of the hepatopancreas of Chinese mitten crab (Eriocheir sinensis) collected in 48 h after injections of MC-LR at doses of 0, 25, 50, and 75 µg/kg. The results revealed that MC-LR induced changes in corresponding gene led to the accumulation of triglycerides. MC-LR exposure affected sterol metabolism. Apoptosis-related genes such as Fas-L, Bcl-XL, Cytc, AiF, p53, PERK, calpain, CASP2, CASP7, α-tubulin, PARP, GF, G12, and PKC were upregulated. Conversely, expression levels of CASP10 and ASK1 were downregulated. Genes related to the regulation of actin cytoskeleton (Rho, ROCK, MLCP, MLC, PAK, and PFN) were upregulated. Further, expression levels of genes encoding fatty acid elongation-related enzymes were upregulated, but the expression of genes related to fatty acid synthesis was slightly down regulated. Taken together, these results demonstrated the hepatic toxicity and molecular mechanisms of changes in lipid metabolism, immune and apoptosis in Chinese mitten crab under the MC-LR-induced stress, which is the first report on crabs and performs a comprehensive analysis and a new insight of the molecular toxicological responses in crabs.

The Mechanism of Lipopolysaccharide Escaping the Intestinal Barrier in Megalobrama amblycephala Fed a High-Fat Diet.

With the popularity of western food characterized by excessive fat and sugars, obesity has currently been a public health issue. Low-grade chronic inflammation accompanied by obesity increases the risk of multiple epidemics such as diabetes, cancer and cardiovascular diseases. Here, we show that feeding Megalobrama amblycephala with a high-fat diet (HFD) drives obesity-related chronic inflammation and the penetration of lipopolysaccharide (LPS). Interference with antibiotics inhibits the produce of LPS and this alleviates the sustained release of pro-inflammatory factors induced by HFD. LPS penetration is attributed to weakened intestinal mucus barrier after high-fat exposure. Mechanically, the consumption of HFD inhibits the secretion of mucin 2 (MUC2) due to the induction of endoplasmic reticulum stress mediated by the inositol-requiring enzyme 1 (IRE1) /X box-binding protein 1 (XBP1) pathway in goblet cells. Furthermore, excessive lipid exacerbates the leakage of LPS across the intestinal epithelial cell barrier via the transcellular pathway. Mechanically, lipid increases the internalization of LPS in intestinal epithelial cells depending on the activation of fatty acid translocase (FAT/CD36). These results demonstrate that HFD causes the penetration of LPS due to the weakened intestinal mucosal barrier and the assistance of CD36.

Acute exposure to microcystin-LR induces hepatopancreas toxicity in the Chinese mitten crab (Eriocheir sinensis).

The Chinese mitten crab is an important economic species in the Chinese aquaculture industry due to its rich nutritional value and distinct flavor. The hepatopancreas is a popular edible part of the Chinese mitten crab, and therefore, hepatopancreatic health directly determines its quality. However, a large-scale outbreak of hepatopancreatic necrosis syndrome ("Shuibiezi" disease in Chinese), which is caused by abiotic agents correlated with cyanobacteria bloom outbreaks, adversely affects the Chinese mitten crab breeding industry. Cyanobacterial blooms that occur in high-density farming ponds can produce microcystin-LR (MC-LR), which is hepatotoxic in fish and mammals. Hepatopancreas toxicity of MC-LR (0, 25, 50 and 75 µg/kg) was investigated after 48 h of exposure. The MC-LR can cause hepatopancreatic injury by inducing hepatopancreatic structural damage, subcellular structural changes, and cell apoptosis, followed by enhanced lipid peroxidase, reactive oxygen species, and apoptosis-related enzyme (Caspase 3, 8, and 9) activities. These in turn promote gene and protein expression of apoptosis-associated proteases (Caspase 3, 7, and 8, Bcl-2, and Bax), and alter antioxidant system responses (superoxide dismutase, glutathione S-transferase, glutathione peroxidase, glutathione reductase activities, and glutathione content). The present study is the first report on MC-LR hepatotoxicity in the Chinese mitten crab and confirms hepatopancreas toxicity, providing a theoretical basis for enhancing MCs resistance and developing preventive and curative measures against hepatopancreatic disease in the Chinese mitten crab breeding industry.

Dietary reduced glutathione supplementation can improve growth, antioxidant capacity, and immunity on Chinese mitten crab, Eriocheir sinensis.

Eriocheir sinensis is an important aquaculture species in China, and its yield and quality are threatened by oxidative stress caused by deteriorating water conditions. Reduced glutathione (GSH) is an endogenous antioxidant, but whether dietary GSH can increase the resistance of E. sinensis to environmental stress remains unclear. Therefore, in this study, crabs were fed with dietary GSH (0, 300, 600, 900, and 1200 mg/kg diet weight) for up to 10 weeks to determine the effects of different dietary GSH concentrations on growth, antioxidant capacity, and immunity of E. sinensis. The results showed that the weight gain rate and survival rate increased significantly as dietary GSH levels increased from 0 to 900 mg/kg, but decreased at 1200 mg/kg. Compared with the control group, the diet supplemented with 900 mg/kg GSH not only increased the concentration of GSH in the haemolymph and hepatopancreas, but also enhanced the activity of glutathione peroxidase (GSH-Px) (p < 0.05). Diets supplemented with 600 or 900 mg/kg GSH significantly increased the enzymes activities of superoxide dismutase (SOD), lysozyme (LZM), alkaline phosphatase, and acid phosphatase, and significantly decreased the content of malondialdehyde. To understand the changes in the activity of these enzymes further, the expression of related genes was detected. Diets supplemented with 600 or 900 mg/kg GSH significantly upregulated the genes expressions of cytosolic manganese SOD, mitochondrial manganese SOD, copper, zinc-SOD, GSH-Px, LZM, and prophenoloxidase activating factor, and significantly down regulated the expression of Toll-like receptor 1, Toll-like receptor 2, Dorsal, and the myeloid differentiation factor 88. However, a diet supplemented with 1200 mg/kg GSH decreased those positive indicators. Overall, our results demonstrated that an appropriate diet supplemented with 600 or 900 mg/kg GSH enhances antioxidant capacity and immunity, which will enhance the general health of E. sinensis.

Influences of glycyrrhetinic acid (GA) dietary supplementation on growth, feed utilization, and expression of lipid metabolism genes in channel catfish (Ictalurus punctatus) fed a high-fat diet.

An 8-week feeding trial was performed to test the effects of glycyrrhetinic acid (GA) on growth and some gene expression of hepatic lipid metabolism in channel catfish (initial body weight, 3.5 ± 0.02 g) fed high-fat diets. Fish were fed the control diet, high-fat diet (HFD), and HFD supplemented with 0.4, 0.8, and 1.2 mg/kg GA in 15 tanks at a stocking density of 21 fish/tank. Fish fed HFD were significantly lower in body weight gain and specific growth rate but higher in feed intake and feed conversion ratio in comparison to the control. Supplement of GA at 1.2 mg/kg remarkably improved these parameters as compared to the control diet. High levels of cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL) in plasma were observed in fish fed HFD; the opposite was observed for fish fed HFD supplemented with GA. The transcription of fatty acid synthase (FAS), sterol regulatory element-binding protein-1 (SREBP1), liver X receptor alpha (LXRα), and hormone-sensitive lipase (HSL) was upregulated, while that of carnitine palmitoyltransferase I (CPT1), peroxisome proliferator-activated receptors alpha (PPARα), acyl-CoA oxidase (ACO), and microsomal triglyceride transfer protein (MTTP) mRNA expression were downregulated in fish fed HFD. The opposite was observed in fish fed HFD supplemented with GA as well as the control group. In conclusion, supplementing the HFD with GA at 1.2 mg/kg could improve the growth performance and lipid metabolism of channel catfish consuming HFD.

Dietary glutathione supplementation enhances antioxidant activity and protects against lipopolysaccharide-induced acute hepatopancreatic injury and cell apoptosis in Chinese mitten crab, Eriocheir sinensis.

Eriocheir sinensis (E. sinensis) is an important aquaculture species in China. However, deteriorating water environments lead to oxidative stress in these crabs, which subsequently reduces their quality and yield. Glutathione (GSH) is an endogenous antioxidant that is used to mitigate oxidative stress. However, whether dietary GSH can enhance the resistance of E. sinensis to oxidative stress remains unclear. Herein, crabs were fed dietary GSH (the basal diet was supplemented with 0, 300, 600, 900, and 1200 mg/kg diet weight of GSH) for up to 3 weeks and, then, challenged with lipopolysaccharide (LPS; 400 µg/kg body weight). After 6 h, their hepatopancreas were sampled. Diet supplementation with 600 and 900 mg/kg diet weight GSH not only increased the content of GSH in the hepatopancreas, but also enhanced the activities and mRNA expressions of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione-S-transferase (GST) (P < 0.05), compared to that in control crabs challenged with LPS alone. Diet supplementation with 600 or 900 mg/kg GSH also significantly increased the enzyme activities of GSH reductase and γ-glutamyl cysteine synthetase (γ-GCS) in LPS-treated crabs. Haematoxylin-eosin (HE) staining, electron microscopy, and flow cytometry were used to examine the structure and subcellular structure of and apoptosis in the hepatopancreas. The histopathology and sub-microstructure analysis results also showed that diet supplementation with 600 or 900 mg/kg GSH significantly alleviated damage in crabs challenged with LPS and decreased reactive oxygen species (ROS) levels and cell apoptosis ratios in the hepatopancreas, compared to the LPS-treated crabs. To further understand the effect of dietary GSH on LPS-induced apoptosis, the activities and gene or protein expressions of apoptosis-related factors were evaluated. As a result, diet supplementation with 600 or 900 mg/kg GSH significantly decreased the activities of caspases-3, -8, and -9 and inhibited the relative expression of caspase-3 and -8 but increased the expression of B-cell lymphoma-2 (bcl-2) and B-cell lymphoma-2-associated X inhibitor (bax inhibitor) in crabs challenged with LPS. This treatment further significantly downregulated the relative protein levels of caspase-3, -8, -9 and Bax and upregulated those of Bcl-2 in crabs challenged with LPS. However, treatment with 1200 mg/kg GSH caused the opposite effects. Overall, our results reveal that appropriate diets supplemented with 600 or 900 mg/kg GSH could enhance the antioxidant capacity and anti-apoptotic mechanisms in crabs after LPS injection, thereby providing a theoretical basis for the application of dietary GSH in E. sinensis.

Effects of dietary protein level on growth performance, digestive enzyme activity, and gene expressions of the TOR signaling pathway in fingerling Pelteobagrus fulvidraco.

An 8-week feeding trial was conducted to investigate effects of dietary protein levels (37, 40, and 43%) on the growth performance, feed utilization, digestive enzyme activity, and gene expressions of target of rapamycin (TOR) signaling pathway in fingerling yellow catfish. One hundred and eighty fingerlings (average weight 0.77 ± 0.03 g) were equally distributed across four replicate tanks for each of the three treatments, with 15 fish per tank. No difference (P > 0.05) was observed in initial body weight, survival rate (SR), hepatosomatic index (HSI), viscera index (VSI), dressing percentage (DP), and condition factor (CF) among all the treatments. The diet containing 40% protein increased significantly (P < 0.05) final body weight, weight gain rate (WGR), specific growth rate (SGR), protein efficiency ratio (PER), nitrogen retention (NRE), and energy retention (ERE) in fish. The highest protease activity in the stomach and intestine was observed in the P40 group (P < 0.05), while amylase and lipase were not significantly different (P > 0.05). The transcriptional levels of IGF-1, IGF-1R, and Akt were significantly (P < 0.05) higher in fish fed P40 or P43 than those of fish fed P37. TOR and S6K1 mRNA expressions were significantly (P < 0.05) increased in the P40 groups. Hence, the diet containing 40% protein would be suitable for the optimum growth and effective protein utilization of fingerling Pelteobagrus fulvidraco. In vitro, the transcriptional levels of IGF-1, IGF-1R, Akt, TOR, and S6K1 in hepatocyte supplemented with a 40-µM mixed amino acids were significantly (P < 0.05) higher compared to other treatments. No difference (P > 0.05) was observed in eukaryotic translation initiation factor 4E-binding protein 1 in vivo and in vitro among all the treatments. Effects of dietary protein level on growth performance likely are involved in the activation of TOR signaling pathway in fingerling Pelteobagrus fulvidraco.

Chronic inflammation is a key to inducing liver injury in blunt snout bream (Megalobrama amblycephala) fed with high-fat diet.

The aim of this article is to investigate the mechanism of lipotoxicity induced by high-fat diets (HFD) in Megalobrama amblycephala. In the present study, fish (average initial weight 40.0 ±â€¯0.35 g) were fed with two fat levels (6% and 11%) diets with four replicates for 60 days. At the end of the feeding trial, fish were challenged by thioacetamide (TAA) and survival rate was recorded for the next 96 h. The result showed that long-term HFD feeding induced a significant increase (P < 0.05) in the levels of aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) in plasma. In addition, liver histopathological analysis showed an increased dilation of the blood vessels, erythrocytes outside of the blood vessels and vacuolization in fish fed with high-fat diet. After TAA challenge, compared with group fed with normal-fat diets (NFD), fish fed with HFD showed a significantly (P < 0.05) low survival rate. After feeding Megalobrama amblycephala with HFD for 60 days, the protein content and gene expression of pro-inflammatory factors were significantly elevated (P < 0.05). The protein and gene relative expressions of a Caspase-3, Caspase-9 and CD68 were significantly increased (P < 0.05), while antioxidant-related enzyme activities were significantly reduced (P < 0.05) in the liver of fish fed with HFD. In addition, HFD feeding also induced genotoxicity. Comet assay showed a significantly (P < 0.05) elevated DNA damage in blunt snout bream fed with HFD. Compared with normal-fat diets (NFD) group, the protein expression of γH2AX and gene expressions involved in cell cycle arrest were significantly increased (P < 0.05) in fish fed with HFD. Data in this research showed that lipotoxicity induced by HFD was likely mediated by chronic inflammation regulating macrophage recruitment, apoptosis and DNA damage. The study was valuable to understand the mechanism by which liver injury is induced in fish fed with HFD.

Flexible 64 × 64 Pixel AMOLED Displays Driven by Uniform Carbon Nanotube Thin-Film Transistors.

Carbon nanotube (CNT) thin-film transistors are expected to be promising for use in flexible electronics including flexible and transparent integrated circuits and in wearable chemical and physical sensors and for driving the circuits of flexible display panels. However, current devices based on CNT channels suffer from poor performance uniformity and low manufacturing yield; therefore, they are still far from being practical. This is usually caused by nonuniform deposition of the semiconducting CNTs and the rough surface of flexible substrates. Here, we report CNT thin-film transistors (TFTs) driving a flexible 64 × 64 pixel active matrix light-emitting diode display (AMOLED) by improving the formation of uniform CNT films and developing a new pretreatment technique for flexible substrates. The achieved AMOLED has uniform brightness and a high yield of 99.93% in its 4096 pixels. More than 8000 TFTs with high-purity semiconducting CNTs as the channel material show an average on-off current ratio of ∼107 and a carrier mobility of 16 cm2 V-1 s-1. The standard deviations of the on-state current and the carrier mobility are 4.1 and 6.5%, respectively. Our result shows that the panel driven by high-purity semiconducting CNTs is a promising strategy for the development of next-generation flexible, large-area displays.

Metformin improves the glucose homeostasis of Wuchang bream fed high-carbohydrate diets: a dynamic study.

After a 12-week feeding trial, the glucose tolerance test was performed in Megalobrama amblycephala to evaluate the effects of metformin on the metabolic responses of glycolipids. Plasma insulin peaked at 2 h, then decreased to the basal value at 8-12 h post-injection. Plasma triglyceride levels and liver glycogen contents of the control group was decreased significantly during the first 2 and 1 h, respectively. Then, they returned to basal values at 12 h. During the whole sampling period, the high-carbohydrate groups had significantly higher levels of plasma metabolites and liver glycogen than those of the control group, and metformin supplementation enhanced these changes (except insulin levels). Glucose administration lowered the transcriptions of ampk α1, ampk α2, pepck, g6pase, fbpase, cpt IA and aco, the phosphorylation of Ampk α and the activities of the gluconeogenic enzymes during the first 2-4 h, while the opposite was true of glut 2, gs, gk, pk, accα and fas. High-carbohydrate diets significantly increased the transcriptions of ampk α1, ampk α2, glut 2, gs, gk, pk, accα and fas, the phosphorylation of Ampk α and the activities of the glycolytic enzymes during the whole sampling period, while the opposite was true for the remaining indicators. Furthermore, metformin significantly upregulated the aforementioned indicators (except accα and fas) and the transcriptions of cpt IA and aco. Overall, metformin benefits the glucose homeostasis of Megalobrama amblycephala fed high-carbohydrate diets through the activation of Ampk and the stimulation of glycolysis, glycogenesis and fatty acid oxidation, while depressing gluconeogenesis and lipogenesis.

Glucose-6-phosphate dehydrogenase in blunt snout bream Megalobrama amblycephala: molecular characterization, tissue distribution, and the responsiveness to dietary carbohydrate levels.

This study aimed to characterize the full-length cDNA of glucose-6-phosphate dehydrogenase (G6PD) from Megalobrama amblycephala with its responses to dietary carbohydrate levels characterized. The cDNA obtained covered 2768 bp with an open reading frame of 1572 bp. Sequence alignment and phylogenetic analysis revealed a high degree of conservation (77-97%) among most fish and other higher vertebrates. The highest transcription of G6PD was observed in kidney followed by liver, whereas relatively low abundance was detected in eye. Then, the transcriptions and activities of G6PD as well as lipid contents were determined in the liver, muscle, and the adipose tissue of fish fed two dietary carbohydrate levels (30 and 42%) for 12 weeks. Hepatic transcriptions of fatty acid synthetase (FAS), acetyl-CoA carboxylase α (ACCα), sterol regulatory element-binding protein-1 (SREBP1), and peroxisome proliferator-activated receptor γ (PPARγ) were also measured to corroborate the lipogenesis derived from carbohydrates. The G6PD expressions and activities in both liver and the adipose tissue as well as the lipid contents in whole-body, liver, and the adipose tissue all increased significantly after high-carbohydrate feeding. Hepatic transcriptions of FAS, ACCα, SREBP1, and PPARγ were also up-regulated remarkably by the intake of a high-carbohydrate diet. These results indicated that the G6PD of M. amblycephala shared a high similarity with that of other vertebrates. Its expressions and activities in tissues were both highly inducible by high-carbohydrate feeding, as also held true for the transcriptions of other enzymes and/or transcription factors involved in lipogenesis, evidencing an enhanced lipogenesis by high dietary carbohydrate levels.

Benfotiamine, a Lipid-Soluble Analog of Vitamin B1, Improves the Mitochondrial Biogenesis and Function in Blunt Snout Bream (Megalobrama amblycephala) Fed High-Carbohydrate Diets by Promoting the AMPK/PGC-1ß/NRF-1 Axis.

This study evaluated the effects of benfotiamine on the growth performance and mitochondrial biogenesis and function in Megalobrama amblycephala fed high-carbohydrate (HC) diets. The fish (45.25 ± 0.34 g) were randomly fed six diets: the control diet (30% carbohydrate, C), the HC diet (43% carbohydrate), and the HC diet supplemented with different benfotiamine levels (0.7125 (HCB1), 1.425 (HCB2), 2.85 (HCB3), and 5.7 (HCB4) mg/kg) for 12 weeks. High-carbohydrate levels remarkably decreased the weight gain rate (WGR), specific growth rate (SGR), relative feed intake (RFI), feed conversion ratio (FCR), p-adenosine monophosphate (AMP)-activated protein kinase (AMPK)α/t-AMPKα ratio, peroxisome proliferator-activated receptor-γ coactivator-1ß (PGC-1ß) and nuclear respiratory factor-1 (NRF-1) protein expression, complexes I, III, and IV activities, and hepatic transcriptions of cytochrome b (CYT-b) and cytochrome c oxidase-2 (COX-2), whereas the opposite was true for plasma glucose, glycated serum protein, advanced glycation end product and insulin levels, tissue glycogen and lipid contents, hepatic adenosine triphosphate (ATP) and AMP contents and ATP/AMP ratio, complexes V activities, and the expressions of AMPKα-2, PGC-1ß, NRF-1, mitochondrial transcription factor A (TFAM), mitofusin-1 (Mfn-1), optic atrophy-1 (Opa-1), dynamin-related protein-1 (Drp-1), fission-1 (Fis-1), mitochondrial fission factor (Mff), and ATP synthase-6 (ATP-6). As with benfotiamine supplementation, the HCB2 diet remarkably increased WGR, SGR, tissue glycogen and lipid contents, AMP content, p-AMPKα/t-AMPKα ratio, PGC-1ß and NRF-1 levels, complexes I, III, IV, and V activities, and hepatic transcriptions of AMPKα-2, PGC-1ß, NRF-1, TFAM, Mfn-1, Opa-1, CYT-b, COX-2, and ATP-6, while the opposite was true for the remaining indicators. Overall, 1.425 mg/kg benfotiamine improved the growth performance and mitochondrial biogenesis and function in fish fed HC diets by the activation of the AMPK/PGC-1ß/NRF-1 axis and the upregulation of the activities and transcriptions of mitochondrial complexes as well as the enhancement of mitochondrial fusion coupled with the depression of mitochondrial fission.

The mechanism of action of a fat regulator: Glycyrrhetinic acid (GA) stimulating fatty acid transmembrane and intracellular transport in blunt snout bream (Megalobrama amblycephala).

High-fat diets are associated with fatty liver and aberrant hepatic lipid metabolism, and glycyrrhetinic acid (GA) has been shown to exert a beneficial effect on lipolysis and fat deposition in fish. In the present study, we evaluated the effect of GA on the growth performance and expression of hepatic lipid transport related genes in blunt snout bream (Megalobrama amblycephala) fed a high fat diet. Two hundred and sixteen fish (average body weight: 45.57 g ±â€¯0.98 g) were fed three experimental diets (6% fat/L6 group, control, 11% fat/L11 group, and 11% fat with 0.3 mg kg-1 GA/L11GA group) for 8 weeks. Compared to the control group, the weight gain and specific growth rate of high-fat fed group at the end of the trialwere significantly improved (P < .05).However, GA showed no effect on animals' growth performance(P > .05). Dietary supplementation with 0.3 mg kg-1 GA significantly decreased the hepatosomatic index, viscera/body ratio, and intraperitoneal fat ratio (P < .05), and up-regulated the expression levels of fatty acids transport protein (FATP), fatty acids binding protein (FABP), fatty acid translocase (CD36), carnitine palmitoyl transferase I (CPT1) and peroxisome proliferators-activated receptors α (PPARα) compared to both the L6 group and L11 group (P < .05). However, no significant difference was observed in fatty acid synthetase (FAS), acetyl-CoA carboxylase α (ACCα), or lipoprotein lipase (LPL) between groups (P > .05). In conclusion, GA significantly rescued high-fat diet induced hepatic lipid accumulation and metabolism dysfunction in M. amblycephalaby stimulating hepatic fatty acid transport and ß-oxidation. Dietary GA may be used as a promising supplement to alleviate high-fat diet induced side effects on M. amblycephala.

Ultrahigh-performance transparent conductive films of carbon-welded isolated single-wall carbon nanotubes.

Single-wall carbon nanotubes (SWCNTs) are ideal for fabricating transparent conductive films because of their small diameter, good optical and electrical properties, and excellent flexibility. However, a high intertube Schottky junction resistance, together with the existence of aggregated bundles of SWCNTs, leads to a degraded optoelectronic performance of the films. We report a network of isolated SWCNTs prepared by an injection floating catalyst chemical vapor deposition method, in which crossed SWCNTs are welded together by graphitic carbon. Pristine SWCNT films show a record low sheet resistance of 41 ohm □-1 at 90% transmittance for 550-nm light. After HNO3 treatment, the sheet resistance further decreases to 25 ohm □-1. Organic light-emitting diodes using this SWCNT film as anodes demonstrate a low turn-on voltage of 2.5 V, a high current efficiency of 75 cd A-1, and excellent flexibility. Investigation of isolated SWCNT-based field-effect transistors shows that the carbon-welded joints convert the Schottky contacts between metallic and semiconducting SWCNTs into near-ohmic ones, which significantly improves the conductivity of the transparent SWCNT network. Our work provides a new avenue of assembling individual SWCNTs into macroscopic thin films, which demonstrate great potential for use as transparent electrodes in various flexible electronics.

Effects of dietary glucose and starch levels on the growth, apparent digestibility, and skin-associated mucosal non-specific immune parameters in juvenile blunt snout bream (Megalobrama amblycephala).

A 10-week feeding trial was performed to evaluate the effects of different types and levels of carbohydrates in growth performance, apparent digestibility coefficients and skin-associated mucosal non-specific immune parameters in blunt snout bream (Megalobrama amblycephala). Fish were randomly fed four diets containing two carbohydrates (glucose and starch) diets and two carbohydrates levels (330 and 440 g kg-1). High carbohydrate levels remarkably increased the weight gain rate (WGR), apparent digestibility of dry matters, protein and carbohydrates, body crud protein content, plasma levels of aspartate transaminase (AST), and skin-associated mucosal levels of immunoglobulin M (IgM), HDL cholesterol, lysozyme (LZM), advanced the transcriptions of mucin 2 (Muc2), mucin 5b (Muc5b) and apolipoprotein A-I (apoA-I), whereas the opposite was true for feed conversion ratio (FCR), plasma levels of IgM, skin-associated mucosal levels of major histocompatibility complex (MHC) and ß-Defensins, and the transcriptions of heat shock protein 60 (Hsp60). In addition, carbohydrate types of glucose remarkably increased the survival rate, apparent digestibility of dry matters, protein and carbohydartes, body crud ash, plasma levels of total protein (TP), globulin (GLB), immunoglobulin M (IgM), complement C3 and complement C4 and the transcriptions of Muc5b. Whereas the carbohydrate types of starch remarkably increased viscerosomatic index (VSI), hepatosomatic index (HSI), condition factor (CF), abdominal fat percentage (AFP), apparent digestibility of liquid, advanced the transcriptions of Muc2, apoA-I and heat shock protein 70 (Hsp70). Significant interactions between different types and levels of dietary carbohydrates were also observed in WGR, apparent digestibility of dry matters, protein and liquid, body crud ash, plasma levels of TP, albumin (ALB) and AST, skin-associated mucosal levels of major histocompatibility complex (MHC) and ß-Defensins, and the transcriptions of Muc2 and Muc5b. Our results indicate that inclusion of high level of glucose in the diet of blunt snout bream could improve growth performance, nonspecific immunity, and increase the efficiency of protein, which is suggesting that high level of glucose could be used in feed production. However, the proportion of the specific formula of glucose using in feed needs further study.

Molecular Characterization of the RNA-Binding Protein Quaking-a in Megalobrama amblycephala: Response to High-Carbohydrate Feeding and Glucose/Insulin/Glucagon Treatment.

The RNA-binding protein quaking-a (Qkia) was cloned from the liver of blunt snout bream Megalobrama amblycephala through the rapid amplification of cDNA ends method, with its potential role in glucose metabolism investigated. The full-length cDNA of qkia covered 1,718 bp, with an open reading frame of 1,572 bp, which encodes 383 AA. Sequence alignment and phylogenetic analysis revealed a high degree of conservation (97-99%) among most fish and other higher vertebrates. The mRNA of qkia was detected in all examined organs/tissues. Then, the plasma glucose levels and tissue qkia expressions were determined in fish intraperitoneally injected with glucose [1.67 g per kg body weight (BW)], insulin (0.052 mg/kg BW), and glucagon (0.075 mg/kg BW) respectively, as well as in fish fed two dietary carbohydrate levels (31 and 41%) for 12 weeks. Glucose administration induced a remarkable increase of plasma glucose with the highest value being recorded at 1 h. Thereafter, it reduced to the basal value. After glucose administration, qkia expressions significantly decreased with the lowest value being recorded at 1 h in liver and muscle and 8 h in brain, respectively. Then they gradually returned to the basal value. The insulin injection induced a significant decrease of plasma glucose with the lowest value being recorded at 1 h, whereas the opposite was true after glucagon load (the highest value was gained at 4 h). Subsequently, glucose levels gradually returned to the basal value. After insulin administration, the qkia expressions significantly decreased with the lowest value being attained at 2 h in brain and muscle and 1 h in liver, respectively. However, glucagon significantly stimulated the expressions of qkia in tissues with the highest value being gained at 6 h. Moreover, high dietary carbohydrate levels remarkably increased plasma glucose levels, but down-regulated the transcriptions of qkia in tissues. These results indicated that the gene of blunt snout bream shared a high similarity with that of the other vertebrates. Glucose and insulin administration, as well as high-carbohydrate feeding, remarkably down-regulated its transcriptions in brain, muscle and liver, whereas the opposite was true after the glucagon load.

Fishmeal replacement by rice protein concentrate with xylooligosaccharides supplement benefits the growth performance, antioxidant capability and immune responses against Aeromonas hydrophila in blunt snout bream (Megalobrama amblycephala).

This study aimed to investigate the effects of fishmeal (FM) replacement by rice protein concentrate (RPC) with a xylooligosaccharides supplement on the growth performance, antioxidant capability and immune response against Aeromonas hydrophila in blunt snout bream (Megalobrama amblycephala). Fish (46.85 ±â€¯0.34 g) were randomly assigned to one of 6 diets, namely the control diet (containing FM), the RPC diet (FM replaced by RPC) and RPC diet supplemented with 0.5, 1.5, 2.3 and 3% XOS respectively, for 8 weeks. After the feeding trial, fish were challenged by Aeromonas hydrophila for 96 h with the blood and liver sample obtained at 48 and 96 h respectively. The results showed that the final weight, weight gain and protein efficiency ratio of fish fed RPC diet were significantly (P < 0.05) lower than that of the control group, whereas the opposite was true for FCR. However, the supplement of 1.5% XOS remarkably (P < 0.05) improved these parameters compared to the control diet. Plasma total iron binding capacity of fish fed the RPC diet showed little difference (P > 0.05) with that of the control group, but it enhanced significantly (P < 0.05) with the supplement of 1.5% XOS compared to the control group. After bacterial infection, plasma lysozyme (LYM), complement 3, complement 4, myeloperoxidase (MPO), acid phosphatase (ACP) and alkaline phosphatase activities, as well as immunoglobulin M, levels all increased significantly (P < 0.05) with the maximum value is attained at 48 h, then they decreased significantly (P < 0.05) with further increasing time at 96 h. Similar results were also observed in liver superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities as well as malondialdehyde (MDA) content. Regarding dietary treatment, these parameters of fish fed RPC diet showed little difference (P > 0.05) with those fed the control diet but were significantly enhanced (P < 0.05) when RPC diet was supplemented with 1.5-2.3% XOS, except for hepatic (MDA) content which showed an opposite trend compared to the control group. After 96 h of challenge, the relative percentage survival (RPS) of fish fed XOS was significantly higher (P < 0.05) than that of fish offered the control and RPC diet. In addition, significant (P < 0.05) interactions between dietary XOS and sampling time were also observed in plasma LYM, MPO, ACP, and hepatic SOD, CAT, GPX, MDA, as well as RPS. In conclusion, this study indicated that dietary supplementation of 1.5%XOS could significantly improve the growth performance, antioxidant capability, innate immunity and A. hydrophila resistance of blunt snout bream fed diets with FM replaced by RPC.

Molecular characterization of fructose-1,6-bisphosphatase 1b in blunt snout bream Megalobrama amblycephala and the transcriptional response to glucose loading after the adaptation to high-carbohydrate diets.

This study aimed to characterize the full-length complementary DNA (cDNA) of fructose-1,6-bisphosphatase 1b (FBP1b) from fish Megalobrama amblycephala, and investigate its transcriptional response to glucose administration after the adaptation to high-carbohydrate diets. The cDNA obtained covered 1435 bp with an open reading frame of 1014 bp. Sequence alignment and phylogenetic analysis revealed a high degree of conservation (76-96%) among most fish and other vertebrates, retaining one N-linked glycosylation site, one N-terminal acetylation site, 13 phosphorylation sites, one fructose-1,6-bisphosphatase (FBPase) active site, five metal-binding sites, four substrate-binding sites, and several AMP-binding sites. The highest messenger RNA (mRNA) level of FBP1b was observed in liver followed by intestine, whereas relatively low values were detected in heart, gill, and eye. Then, the mRNA levels of FBP1b and the FBPase activity were both determined in the liver of fish injected intraperitoneally with 1.67 g glucose per kilogram body weight after being fed two dietary carbohydrate levels (30 and 42%) for 11 weeks. After the glucose load, the mRNA levels of FBP1b in both treatments decreased significantly to the basal value at 8 h and showed a slight increase afterward. However, the enzymatic activity showed no statistical difference during the first 4 h, but increased remarkably with further increasing times. In addition, both the mRNA levels and activities decreased significantly with increasing dietary carbohydrate levels. The results indicated that the FBP1b of M. amblycephala shared a high similarity with that of the other vertebrates. Its mRNA expression in liver was downregulated remarkably by a glucose administration, as also held true after the long-term adaptation of a carbohydrate-rich diet.

Molecular characterization of AMP-activated protein kinase α2 from herbivorous fish Megalobrama amblycephala and responsiveness to glucose loading and dietary carbohydrate levels.

This study aimed to characterize the full-length cDNA of AMPKα2 in Megalobrama amblycephala, and evaluate its potential role in glucose homeostasis and carbohydrate metabolism. The cDNA obtained covered 1942bp with an open reading frame of 1635bp encoding 545 amino acids. Multiple alignments and phylogenetic analysis revealed a high homology (91-100%) among most fish and higher vertebrates. This AMPKα2 mRNA predominantly expressed in muscle, liver and brain, while little in gill and intestine. Then, the AMPKα2 expressions were determined in the muscle, liver and brain of fish subjected to a glucose load (injected intraperitoneally with 0, 1.67 and 3.34g glucose per kg body weight) and after a 12-week feeding trial (fed two dietary carbohydrate levels: 30% and 43%), respectively. After the glucose load, plasma glycemia peaked at 1h in fish. Thereafter, it decreased significantly to the basal level at 8h. However, AMPKα2 expression in muscle, liver and brain all decreased significantly during the first 2h, then returned to the basal value at 24h. Unlikely, tissue AMPKα2 expression of fish receiving saline solution increased significantly during the whole sampling period. Additionally, high-carbohydrate diet enhanced its expression in liver and muscle, but not that in brain. These findings indicated that the AMPKα2 gene shared a high degree of conservation with that of the other vertebrates. Muscle, liver and brain AMPKα2 expressions were highly induced by glucose administration. Furthermore, high dietary carbohydrate modified its expressions in these tissues.