Search

The Qinghai-Tibet Plateau (QTP) is an important cushion plant hotspot. However, the distribution of cushion plants on the QTP is unknown, as are the factors that drive cushion plant distribution, limiting our understanding of the evolution of cushion species in the region. In this study, we assessed spatial patterns of total cushion plant diversity (including taxonomic and phylogenetic) over the entire QTP and compared patterns of diversity of cushion plants with different typologies (i.e., compact vs. loose). We also examined how these patterns were related to climatic features. Our results indicate that the southern QTP hosts the highest total cushion plant richness, especially in the south-central Hengduan Mountains subregion. The total number of cushion species declines from south to north and from southeast to northwest. Compact cushion plants exhibit similar patterns as the total cushion plant richness, whereas loose cushion plants show random distribution. Cushion plant phylogenetic diversity showed a similar pattern as that of the total cushion plant richness. In addition, cushion plant phylogenetic community structure was clustered in the eastern and southwestern QTP, whereas random or overdispersed in other areas. Climatic features represented by annual energy and water trends, seasonality and extreme environmental factors, had significant effects on cushion plant diversity patterns but limited effects on the phylogenetic community structure, suggesting that climatic features indeed promote the formation of cushion plants. Because cushion plants play vital roles in alpine ecosystems, our findings not only promote our understanding of the evolution and formation of alpine cushion plant diversity but also provide an indispensable foundation for future studies on cushion plant functions and thus alpine ecosystem sustainability in the entire QTP region.

Memory drove a critical process of feeding habit transformation in Chinese perch when they re-trained to eat dead prey fish. To investigate the regulatory mechanism of cAMP-response element-binding protein (CREB) signaling pathway on the memory of Chinese perch during feeding habit transformation, the phosphorylation levels of upstream signal proteins of CREB between the control group (trained once) and the experimental group (trained twice) were measured. The results illustrated that the re-training was correlated to phosphorylation of extracellular regulated protein kinase (ERK1/2) and calcium/calmodulin-dependent protein kinase II (CaMKII), and dephosphorylation of protein kinase A (PKA) of Chinese perch. Inhibition of ERK1/2-CREB pathway decreased the mRNA levels of memory-related genes ((fos-related antigen 2 (fra2), CCAAT enhancer-binding protein delta (c/ebpb), immediate-early gene zif268 (zif268), proto-oncogenes c-fos (c-fox) and synaptotagmin-IV (sytIV)) and mRNA levels of appetite-related genes (agouti-related peptide (agrp) and ghrelin), and activation of PP1-CREB pathway increased the phosphorylated levels of CREB, the mRNA levels of memory-related genes (fra2, c/ebpb, zif268, and c-fox), and the mRNA levels of appetite-related genes (pro-opiomelanocortin (pomc) and leptin) in primary brain cells of Chinese perch. The memory in Chinese perch feeding habit transformation was associated with the ERK1/2-CREB and PP1-CREB pathways, which could regulate the transcription of memory-related genes and appetite-related genes.

Neuropeptide Y receptor Y8 (NPY8R) is a fish-specific receptor, whose role in feeding regulation remains poorly understood. In the present study, two subtypes of NPY8R (NPY8Ra and NPY8Rb) were identified in Chinese perch, and their amino acid sequences were highly conserved in fish. The predicted tertiary protein structures of human NPY1R, Chinese perch NPY8Ra, and NPY8Rb tended to be conserved as a whole. However, the predicted tertiary protein structures of sc-NPY8Ra and sc-NPY8Rb were different at several sites. Chinese perch NPY8Ra and NPY8Rb were mainly expressed in brain. Intracerebroventricular administration of siRNA-NPY8Rb significantly decreased the mRNA expression levels of NPY8Rb and POMC (appetite-suppressive gene) and significantly increased the food intake of Chinese perch at 2 h and 8 h after injection. Similar result has not been observed in the siRNA-NPY8Ra administration group. The above results suggested that NPY8Ra might not play a role in appetite regulation and NPY8Rb might be an effector in the negative feedback regulation of feeding in Chinese perch.

Improving carbohydrate utilization can contribute to sustainability of aquaculture. In order to explore the feedback mechanism of glucose homeostasis in fish, one control diet (25% carbohydrate and 40% protein), one relatively high carbohydrate diet named HG (42% carbohydrate and 40% protein), and one high dietary carbohydrate coupled with relatively low protein diet named HGP (42% carbohydrate and 25% protein) were fed to grass carp for 40 days. After the feeding trial, HG group impeded the food intake and growth performance of fish compared with the other two groups. Meanwhile, the serum glucose and insulin level were both significantly elevated under the condition of high carbohydrates intake when compared HG with control group. However, although no significant difference was observed in peripheral glucose or insulin between HG and HGP groups, fish fed with HGP diet increased growth performance and food intake compared with the HG group. Gene expression data indicated that fish selectively regulated the expressions of the cerebral anorexigenic genes (cart and pomc) to adapt to the HG and HGP intake. Therefore, the HGP diet with high carbohydrate and low protein was more suitable for grass carp feeding and growth when compared with the other two diets, possibly because the diet composition was closer to the natural food of this fish. In addition, the serum leptin level was highly consistent with changes in food intake and anorexigenic gene expressions when comparing the three experimental diets, indicating that leptin might be the key to mediate the feedback regulation of carbohydrates intake on food intake and appetite in fish.

Chinese perch, Siniperca chuatsi (Basilewsky), is one of the most commercially important cultured fishes in China. In the present study, a high-density genetic linkage map of Chinese perch was constructed by genotyping-by-sequencing technique with an F1 mapping panel containing 190 progenies. A total of 2328 SNPs were assigned to 24 linkage groups (LGs), agreeing with the chromosome haploid number in this species (n = 24). The sex-averaged map covered 97.9% of the Chinese perch genome, with the length of 1694.3 cM and a marker density of 0.7 cM/locus. The number of markers per LG ranged from 57 to 222, with a mean of 97. The length of LGs varied from 43.2 to 108.2 cM, with a mean size of 70.6 cM. The recombination rate of females was 1.5:1, which was higher than that of males. To better understand the distribution pattern of segregation distortion between the two sexes of Chinese perch, the skewed markers were retained and used to reconstruct the sex-specific maps. The 16 segregation distortion regions were identified on 10 LGs of the female map, while 12 segregation distortion regions on eight LGs of the male map. Among these LGs, six LGs matched between the sex-specific maps. This high-density linkage map could provide a solid basis for identifying QTL associated with economically important traits, and for implementing marker-assisted selection breeding of Chinese perch.

Under anoxic conditions, the interactions between As-bearing ferrihydrite (Fh) and As(V)-reducing bacteria are known to cause Fh transformations and As mobilization. However, the impact of different types of organic matter (OM) on microbial As/Fe transformation in As-bearing Fh-organic associations remains unclear. In our study, we therefore exposed arsenate-adsorbed ferrihydrite, ferrihydrite-PGA (polygalacturonic acid), and ferrihydrite-HA (humic acid) complexes to two typical Fe(III)- and As(V)-reducing bacteria, and followed the fate of Fe and As in the solid and aqueous phases. Results show that PGA and HA promoted the reductive dissolution of Fh, resulting in 0.7-1.6 and 0.8-1.9 times more As release than in the OM-free Fh, respectively. This was achieved by higher cell numbers in the presence of PGA, and through Fe-reduction via electron-shuttling facilitated by HA. Arsenic-XAS results showed that the solid-phase arsenite fraction in Fh-PGA and Fh-HA was 15-19% and 27-28% higher than in pure Fh, respectively. The solid-associated arsenite fraction likely increased because PGA promoted cell growth and As(V) reduction, while HA provided electron shuttling compounds for direct microbial As(V)-reduction. Collectively, our findings demonstrate that As speciation and partitioning during microbial reduction of Fh-organic associations are strongly influenced by PGA and HA, as well as the strains' abilities to utilize electron-shuttling compounds.

Activin A belongs to the superfamily of transforming growth factor-β and plays an important role in hormone regulation and tissue development. However, few research studies have been conducted on the effect of activin A on feeding organs in fish. In this study, the zebrafish (Danio rerio) larvae were treated with 1 ng ml-1 activin A for 8 days continuously. The haematoxylin and eosin (H&E) staining section results revealed that the transverse inner diameter of the pharynx and oesophagus significantly increased on the third and eighth days after treatment compared with the control group (P

Carbon catabolite repression (CCR), which is mainly mediated by Cre1 and triggered by glucose, leads to a decrease in cellulase production in Trichoderma reesei. Many studies have focused on modifying Cre1 for alleviating CCR. Based on the homologous alignment of CreA from wild-type Penicillium oxalicum 114-2 (Po-0) and cellulase hyperproducer JUA10-1(Po-1), we constructed a C-terminus substitution strain-Po-2-with decreased transcriptional levels of cellulase and enhanced CCR. Results revealed that the C-terminal domain of CreAPo-1 plays an important role in alleviating CCR. Furthermore, we replaced the C-terminus of Cre1 with that of CreAPo-1 in T. reesei (Tr-0) and generated Tr-1. As a control, the C-terminus of Cre1 was truncated and Tr-2 was generated. The transcriptional profiles of these transformants revealed that the C-terminal chimera greatly improves cellulase transcription in the presence of glucose and thus upregulates cellulase in the presence of glucose and weakens CCR, consistent with truncating the C-terminus of Cre1 in Tr-0. Therefore, we propose constructing a C-terminal chimera as a new strategy to improve cellulase production and alleviate CCR in the presence of glucose.

Mandarin fishes (Sinipercidae) are piscivores that feed solely on live fry. Unlike higher vertebrates, teleosts exhibit feeding behavior driven mainly by genetic responses, with no modification by learning from parents. Mandarin fishes could serve as excellent model organisms for studying feeding behavior. We report a long-read, chromosomal-scale genome assembly for Siniperca chuatsi and genome assemblies for Siniperca kneri, Siniperca scherzeri and Coreoperca whiteheadi. Positive selection analysis revealed rapid adaptive evolution of genes related to predatory feeding/aggression, growth, pyloric caeca and euryhalinity. Very few gill rakers are observed in mandarin fishes; analogously, we found that zebrafish deficient in edar had a gill raker loss phenotype and a more predatory habit, with reduced intake of zooplankton but increased intake of prey fish. Higher expression of bmp4, which could inhibit edar expression and gill raker development through binding of a Xvent-1 site upstream of edar, may cause predatory feeding in Siniperca., He, Li, and Lv et al. took a genomics approach to study innate feeding behavior in mandarin fish. They identify genes related to predatory feeding that underwent rapid adaptive evolution. They also functionally validate the role of bmp4-edar pathway in inducing predatory feeding in zebrafish.

Metabolic engineering of Saccharomyces cerevisiae for high-level production of aromatic chemicals has received increasing attention in recent years. Tyrosol production from glucose by S. cerevisiae is considered an environmentally sustainable and safe approach. However, the production of tyrosol and salidroside by engineered S. cerevisiae has been reported to be lower than 2 g/L to date. In this study, S. cerevisiae was engineered with a push-pull-restrain strategy to efficiently produce tyrosol and salidroside from glucose. The biosynthetic pathways of ethanol, phenylalanine, and tryptophan were restrained by disrupting PDC1, PHA2, and TRP3. Subsequently, tyrosol biosynthesis was enhanced with a metabolic pull strategy of introducing PcAAS and EcTyrAM53I/A354V . Moreover, a metabolic push strategy was implemented with the heterologous expression of phosphoketolase (Xfpk), and then erythrose 4-phosphate was synthesized simultaneously by two pathways, the Xfpk-based pathway and the pentose phosphate pathway, in S. cerevisiae. Furthermore, the heterologous expression of Xfpk alone in S. cerevisiae efficiently improved tyrosol production compared with the coexpression of Xfpk and phosphotransacetylase. Finally, the tyrosol yield increased by approximately 135-folds, compared with that of parent strain. The total amount of tyrosol and salidroside with glucose fed-batch fermentation was over 10 g/L and reached levels suitable for large-scale production.

d-Xylose is the most abundant hemicellulosic monomer on earth, but wild-type Saccharomyces cerevisiae has very limited d-xylose uptake capacity. We conducted bioprospecting for new sugar transporters from the d-xylose-consuming filamentous fungus Trichoderma reesei and identified three candidates belonging to the major facilitator superfamily. When they were expressed in yeast and assayed for d-xylose uptake, one of them, Xltr1p, had d-xylose transport activity that was more efficient than that of Gal2p, an endogenous yeast transporter. Site-directed mutagenesis was used to examine the functional contributions of 13 amino acid residues for the uptake of d-xylose, and these experiments identified particular amino acids that function distinctly in d-xylose vs glucose transport (e.g., F300). Excitingly, the yeast strain expressing the N326FXltr1p variant was able to carry a "high efficiency" transport for d-xylose but was nearly unable to utilize glucose; in contrast, the strain with the F300AXltr1p variant grew on glucose but lost d-xylose transport activity.

The effective utilization of carbohydrate feed sources is important to save protein feed resources and reduce formula feed costs in fish aquaculture. The present study investigated whether high-carbohydrate diet stimulus in the early larval stage of the grass carp (Ctenopharyngodon idellus) could affect glucose metabolism in subsequent life stages (i.e., the juvenile). A 73-day feeding trial was divided to five groups (four treatments and a control). The trial was conducted from the first feeding of larval fish. During the first 66 days, the control was continuously fed a commercial grass carp diet (CD), the FF-3 group was initially fed with 60% malty dextrin diet (MD) for 3 days and then with the CD for 63 days, the YE-7 group was initially fed with 60% MD after yolk-sac exhaustion for 7 days and with the CD for 56 days, the FF-10 group was initially fed with 60% MD for 10 days and then with CD for 56 days, and the FF-66 group was continuously fed to 60% MD. During the next 7 days, all the treatment groups and the control were fed with 35% MD as challenge test. The results showed that short-term stimulation with high-carbohydrate resulted in significantly increased body weights. After 73 days of feeding, the final body weights of the FF-3 and YE-7 groups were significantly higher than that of the control. Early high-carbohydrate manipulation changed the normal structure of the gut tissues of juvenile fish. After a short challenge test (7 days) performed with a 35% carbohydrate diet in juvenile grass carp, the results showed that high-carbohydrate dietary histories affected plasma metabolites and liver (muscle) glycogen storage in the juvenile fish. The mRNA levels of glucokinase and fatty acid synthetase genes increased significantly at the juvenile stage in the first-feeding groups. The phosphoenolpyruvate carboxykinase gene expression in the FF-3 and FF-10 groups decreased by varying degrees. The glycogen synthase gene expression levels in all groups were not affected. Long-term intake of high-carbohydrate feed (FF-66 group) led to the nutritional deficiency and disorder of the glucose metabolism system. In conclusion, our results demonstrated that a high-carbohydrate diet stimulus at first-feeding stage can affect the growth performance, gut morphology, and the homeostasis of glucose metabolism in juvenile of grass carp.

An 8-week feeding trial was conducted to evaluate the effects of dietary carbohydrate to lipid (CHO: L) ratios on growth performance, body composition, serum biochemical indexes, lipid metabolism and gene expression of central appetite regulating factors in Chinese perch (Siniperca chuatsi) (mean initial weight: 12.86 ± 0.10 g). Five isonitrogenous and isoenergetic diets (fish meal, casein as main protein sources) were formulated to contain different graded CHO:L ratio diets ranging from 0.12, 0.86, 1.71, 3.29 and 7.19. Each diet was assigned to triplicate groups of 18 experimental fish for 8 weeks. Our results revealed that final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), protein efficiency ratio (PER) increased with dietary CHO:L ratio from 0.12 to 1.71, and then decreased with further increases in dietary CHO:L ratio. A two-slope broken-line regression analysis based on WGR showed that the optimal dietary CHO: L level for maximum growth performance of fish was 1.60. Crude lipid and crude protein content in the liver and glycogen concentration in the muscle and liver were significantly influenced by the dietary CHO:L ratios (P < 0.05). The lowest crude lipid content in the liver was observed in fish fed the diet with a CHO:L ratio of 1.71(P < 0.05). Dietary CHO:L ratios significantly induced the Glu contents of serum (P < 0.05). The relative expression levels of genes involved in lipid metabolism, such as srebp1 and fas in the liver showed a trend of first decreased and then increased with the increase of dietary CHO:L ratios levels. Appropriate CHO:L ratio in the diet can effectively reduce the accumulation of liver fat. We observed in fish fed the 1.71 CHO:L ratio diet showed higher feed intake, up‐regulated mRNA expression of neuropeptide Y (NPY) and agouti gene-related protein (AGRP), down‐regulated mRNA expression of cocaine-and amphetamine-regulated transcript (CART) and pro‐opiomelanocorticoid (POMC) significantly as compared to control group. Thus, these results provide the theoretical basis for feed formulation to determine the appropriate CHO:L ratio requirement of Chinese perch.

Mandarin fish is a typical carnivorous fish, it can accept artificial diet after domestication, which is significantly essential to optimize its artificial diet. Nevertheless, only few studies were conducted on artificial diet of mandarin fish. Therefore, an 8‐week feeding trial was conducted to evaluate the influence of feeding stimulants on growth performance, feed intake and appetite regulation of mandarin fish. In this trial, six diets were formulated, a basal diet contained 80% of Fish Meal without feeding stimulants, named as Control, 0.4% inosinic acid meal, 0.4% L‐Alanine meal, 3% Yeast meal, 3% a commercial squid extract meal and 0.4% betaine meal were added into the basal diet to make five experimental diets, which were named as IM, AM, YM, SVO and BM respectively. At the end of feeding trial, SVO group showed higher feed intake, up‐regulated mRNA expression of neuropeptide Y (NPY) and down‐regulated mRNA expression of pro‐opiomelanocorticoid (POMC) significantly as compared to control group, which suggested that squid extract improved feed acceptability and promoted appetite in mandarin fish. Similarly, compared to control group, SVO group showed low food conversion ratio, high weight gain and SGR, indicated that squid extract enhanced the growth performance. Our results suggested that the appropriate level of squid extract addition could contribute to optimize artificial diet in mandarin fish.

Dietary lipid oxidation is a lasting concern to aquafeed manufacturers and aquaculture farmers. Here, we determined if there was an association between oxidized fish oil (OFO) and hepatopancreatic injury in Chinese mitten crab, and evaluated the alleviating effects of a combination of vitamins C and E on hepatopancreatic injury. There were significant reductions in the body weight gain, hepatopancreatic index, and feed efficiency in crabs that received OFO. Diets with OFO also resulted in reduced crude fat contents in the hepatopancreas and muscle tissues, and alternations in the hepatopancreatic fatty acid compositions, especially a reduction in polyunsaturated fatty acids. Moreover, dietary OFO exposure reduced the antioxidant defense and non‐specific immune response, caused hepatopancreatic injury, and even apparent whitening. An ultrastructural examination of the whitened hepatopancreas revealed that hepatopancreatic cells were injured at varying degrees following OFO exposure. The combination of vitamins C and E could efficiently maintain a constant fatty acid profile in the hepatopancreas exposed to OFO, thus alleviating OFO‐induced hepatopancreatic injury. In addition, a biochemical analysis indicated that a combination of vitamins C and E not only improved the antioxidant status by mitigating the harmful effects of oxidized oil, but also modulated non‐specific immune responses in the crab that received OFO. Overall, OFO‐induced hepatopancreatic injury may be alleviated by a dietary combination of vitamins C and E, and the feeding of rancid forage fish or diets that contain highly oxidized oil is likely a cause of hepatopancreatic necrosis that is frequently observed in farmed crabs.

As typical herbivorous fish, grass carp possesses greater capability to utilize carbohydrate than carnivorous and omnivorous fish. However, mechanism of carbohydrate utilization in herbivorous fish was unclear. This study is intended to investigate response of grass carp to insufficient or excessive dietary carbohydrate. Grass carp accepted isonitrogenous diets with different carbohydrate levels (15.90, 21.81 and 45.45 g 100 g−1) were cultured. After 8 weeks, weight gain and feed intake were highest in fish fed with medium-carbohydrate diet compared with others. Gene expression data indicated that expressions of glucose-6-phosphatase (G6Pase) were down-regulated and gene expressions of glycogen synthase (GS) were up-regulated in fish accepted lower-carbohydrate diet. In high-carbohydrate group, glucose catabolism was increased by enhanced expressions of glucokinase genes (GK). Meanwhile, fatty acid synthase (FAS) and acetyl coenzyme-A carboxylase (ACC1) genes were significantly up-regulated and lipoprotein lipase and carnitine palmitoyltransferase 1 (CPT1) genes expressions were down-regulate, inducing more lipid deposition. Subsequently, serum cholesterol and total lipid contents were significantly increased, and then induced appetite suppression through up-regulation of leptin and anorexigenic genes expressions. Furthermore, depressed food intake caused lower growth rate in grass carp with excessive carbohydrate intake.

Background As economical traits, food habits domestication can reduce production cost in aquaculture. However, the molecular mechanism underlying food habits domestication has remained elusive. Mandarin fish (Siniperca chuatsi) only feed on live prey fish and refuse artificial diets. In the present study, we domesticated mandarin fish to feed on artificial diets. The two groups were obtained, the fish did not eat artificial diets or ate artificial diets during all of the three domestication processes, named Group W or X, respectively. Results Using transcriptome and metabolome analysis, we investigated the differentially expressed genes and metabolites between the two groups, and found three common pathways related to food habit domestication, including retinol metabolism, glycerolipid metabolism, and biosynthesis of unsaturated fatty acids pathways. Furthermore, the western blotting and bisulfite sequencing PCR analysis were performed. The gene expression of TFIIF and histone methyltransferase ezh1 were significantly increased and decreased in the fish of Group X, respectively. The total DNA methylation levels of TFIIF gene and tri-methylation of histone H3 at lysine 27 (H3K27me3) were significantly higher and lower in the fish of Group X, respectively. Conclusion It was speculated that mandarin fish which could feed on artificial diets, might be attributed to the lower expression of ezh1, resulting in the decreased level of H3K27me3 and increased level of DNA methylation of TFIIF gene. The high expression of TFIIF gene might up-regulate the expression of genes in retinol metabolism, glycerolipid metabolism and glycerophosphoric metabolism pathways. Our study indicated the relationship between the methylation of DNA and histone and food habits domestication, which might be a novel molecular mechanism of food habits domestication in animals.

Growing experimental and clinical evidence suggests that a chronic inflammatory response induced by gut microbiome critically contribute to the development of rheumatoid arthritis (RA). Previous studies demonstrated the disturbance of lymphocyte subpopulations in RA patients. The purpose of this study was to explore the characteristics of gut microbiome and the associations between bacterium and lymphocyte subpopulations as well as cytokines in patients with RA. Fecal samples from 205 RA patients and 199 healthy controls (HCs) were collected for bacterial DNA extraction and 16S ribosomal RNA (rRNA) gene sequencing. The levels of peripheral lymphocyte subpopulation such as T, B, CD4+T, CD8+T, NK, T helper 1 (Th1), Th2, Th17, and regulatory T cells (Tregs) of these subjects were detected by flow cytometry combined with standard absolute counting beads. The serum levels of cytokines interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-17, tumour necrosis factor-α (TNF-α), and interferon-γ (INF-γ) were tested by flow cytometric bead array (CBA). Alpha and beta diversity of gut microbiome were explored by bioinformatics analysis. Spearman rank correlation test was used to explore the relationships between gut microbiome and lymphocyte subsets as well as serum cytokines. The diversity and relative abundance of intestinal microbiota in patients with RA were significantly different from those in HCs. Detailly, the abundant of phylum Proteobacteria in RA patients was more than that in HCs, while Firmicutes was less than in HCs. There was increased relative abundance of genus Clostridium_XlVa as well as genus Blautia, more abundance of Ruminococcus2 in patients with lower levels of T, B, CD4+T, and Tregs. In addition, the relative abundances of Pelagibacterium, Oxalobacter, ClostridiumXlVb, and ClostridiumXVIII were correlated with cytokines. Gut microbiome of RA patients was clearly different from that of HCs. Abnormal bacteria communities are associated with the altered levels of lymphocyte subpopulation and cytokines, which might be one of the pathogenesis of RA.

Branching in long-lived plants can cause scarring at the base and affect wood density, which greatly inhibits wood yield and quality. Eucalyptus urophylla is one of the most important commercial forest tree species in South China, with diverse branch number and branch angles under different genetic backgrounds. However, the main elements and regulatory mechanisms associated with different branching traits in E. urophylla remain unclear. To identify the factors that may influence branching, the transcriptome and metabolome were performed on the shoot apex (SA), lateral shoot apex (LSA), and stem segment at the 5th axillary bud from the shoot apex (S1) in lines ZQUC14 (A) and LDUD26 (B), with A exhibiting a smaller Ba than B. A total of 307.3 million high-quality clean reads and nine hormones were identified from six libraries. Several differentially expressed regulatory factors were identified between the two genotypes of E. urophylla. The Kyoto Encyclopedia of Genes and Genomes pathways were enriched in plant hormone signal transduction, plant hormone biosynthesis and their transport pathways. Furthermore, gene expression pattern analysis identified genes that were significantly downregulated or upregulated in S1 relative to the SA and LSA segments, and the plant hormone signal transduction pathway was constructed to explain branching development. This study clarified the main plant hormones and genes underlying branch numbers and angles of E. urophylla, confirmed that ABA and SA could promote a larger branch angle and smaller branch number, while IAA has an opposite function. Numbers of key candidate genes involved in plant hormone signal transduction were found in the positive regulation of branch formation. These novel findings should aid molecular breeding of branching in Eucalyptus.

High carbohydrate diet-induced damage in gut is linked to changes in gut permeability and microbiota. However, the mechanisms of action are not clear, especially in non-mammals. We performed the gut microbiota profiling in Chinese perch fed with different content of starch diets (0, 10, and 20%) by 16S rRNA sequencing. The gut permeability, metabolites, histological analysis, and inflammatory infiltration were evaluated. We found that gut microbial diversity, beneficial bacteria quantity, and lactic acid content were higher in C10 group than in the other groups. The lower level of gut microbial diversity was observed in C20 group, and mycoplasma was the overwhelmingly dominant species, but the butyric acid-producing bacteria and butyric acid level were significantly reduced. The gut permeability in C20 group was also increased due to the decreased mRNA expression levels of tight junction proteins caused by the butyric acid deficiency and gut lipid droplets accumulation. Then a large amount of LPS penetrated into the plasma, resulting in inflammation. These results suggested that high carbohydrate diet-induced damage in gut could be attributed to the endotoxemia, permeability, and gut microbiota, especially the role of mycoplasma and butyric acid-producing bacteria. In addition, predictive functional profiling of microbial communities by PICRUSt showed that C10 group enriched pathway related to membrane transport and down-regulated the pathways related to energy, coenzyme factor and vitamin metabolism, while C20 group exhibited reversed results. These data showed that the high-carbohydrate diet reversed the beneficial changes in gut microbial metabolism resulted from the medium-carbohydrate diet, and further demonstrated that microbiota played a key role in the gut damage caused by the high-carbohydrate diet. Our findings provide a reference for the targeted regulation of gut microbiota to mitigate the damage caused by the increase in starch content in fish feed (cost saving).

Background Early nutritional programming affects a series of metabolism, growth and development in mammals. Fish also exhibit the developmental plasticity by early nutritional programming. However, little is known about the effect of early amino acid programming on growth and metabolism. Methods In the present study, zebrafish (Danio rerio) was used as the experimental animal to study whether early leucine stimulation can programmatically affect the mechanistic target of rapamycin (mTOR) signaling pathway, growth and metabolism in the later life, and to undercover the mechanism of epigenetic regulation. Zebrafish larvas at 3 days post hatching (dph) were raised with 1.0% leucine from 3 to 13 dph during the critical developmental stage, then back to normal water for 70 days (83 dph). Results The growth performance and crude protein content of zebrafish in the early leucine programming group were increased, and consistent with the activation of the mTOR signaling pathway and the high expression of genes involved in the metabolism of amino acid and glycolipid. Furthermore, we compared the DNA methylation profiles between the control and leucine-stimulated zebrafish, and found that the methylation levels of CG-differentially methylated regions (DMGs) and CHH-DMGs of genes involved in mTOR signaling pathway were different between the two groups. With quantitative PCR analysis, the decreased methylation levels of CG type of Growth factor receptor-bound protein 10 (Grb10), eukaryotic translation initiation factor 4E (eIF4E) and mTOR genes of mTOR signaling pathway in the leucine programming group, might contribute to the enhanced gene expression. Conclusions The early leucine programming could improve the protein synthesis and growth, which might be attributed to the methylation of genes in mTOR pathway and the expression of genes involved in protein synthesis and glycolipid metabolism in zebrafish. These results could be beneficial for better understanding of the epigenetic regulatory mechanism of early nutritional programming.

In Trichoderma reesei, carbon catabolite repression (CCR) significantly downregulates the transcription of cellulolytic enzymes, which is usually mediated by the zinc finger protein Cre1. It was found that there is a conserved region at the C-terminus of Cre1/CreA in several cellulase-producing fungi that contains up to three continuous S/T phosphorylation sites. Here, S387, S388, T389, and T390 at the C-terminus of Cre1 in T. reesei were mutated to valine for mimicking an unphosphorylated state, thereby generating the transformants Tr_Cre1S387V, Tr_Cre1S388V, Tr_Cre1T389V, and Tr_Cre1T390V, respectively. Transcription of cel7a in Tr_ Cre1S388V was markedly higher than that of the parent strain when grown in glucose-containing media. Under these conditions, both filter paperase (FPase) and p-nitrophenyl-β-D-cellobioside (pNPCase) activities, as well as soluble proteins from Tr_Cre1S388V were significantly increased by up to 2- to 3-fold compared with that of other transformants and the parent strain. The results suggested that S388 is critical site of phosphorylation for triggering CCR at the terminus of Cre1. To our knowledge, this is the first report demonstrating an improvement of cellulase production in T. reesei under CCR by mimicking dephosphorylation at the C-terminus of Cre1. Taken together, we developed a precision engineering strategy based on the modification of phosphorylation sites of Cre1 transcription factor to enhance the production of cellulase in T. reesei under CCR., Graphical Abstract Schematic diagram on transcriptional regulation of cellulase expression in mutant and parent strains. We developed a precision engineering strategy by mimicking dephosphorylation at a key residue S388 of Cre1 to improve the production of cellulase in fungal species under CCR, highlighting that this technology can accelerate the industrial process of lignocellulosic biorefinery.

Although studies have determined that epigenetics plays an essential role in regulating metabolism in mammals, research on nutrition-related DNA methylation remains to be lacking in teleosts. In the present study, we provided a hepatic whole-genome DNA methylation analysis in grass carp fed with moderate- or excessive-carbohydrate-level diet. Although a high-carbohydrate (HC) diet significantly changed the mRNA expression levels of metabolic genes, it did not affect the global genomic DNA methylation levels in grass carp liver. However, compared with the control group, 3,972 genes were hyper-methylated and 2,904 genes were hypo-methylated in the promoter region. Meanwhile, 10,711 genes were hyper-methylated and 6,764 genes were hypo-methylated in the gene body region in the HC group. These differentially methylated genes (DMGs) were enriched in multiple pathways, including carbohydrate metabolism, insulin pathway, lipid metabolism, and adipocytokine signaling pathway. In addition, the variations in DNA methylation significantly regulated the transcription levels of key genes of metabolism, which could affect the glucose concentrations and the lipid deposition of grass carp. Furthermore, we compared the DNA methylation alterations of genes in glucose metabolism and obesity pathways of grass carp with those of mammalian models in different nutritional states. The results showed that most of the DMGs in grass carp were also regulated by DNA methylation in mammals when the nutritional state changed. The findings revealed more differentially methylated regions and candidate genes for glucose metabolism and broken species boundaries.

Food intake of carnivorous fish decreases after feeding on a carbohydrate-rich diet. However, the molecular mechanism underlying the anorexia caused by high-carbohydrate diets has remained elusive. We domesticated the mandarin fish to feed on carbohydrate-rich (8%) diets. After 61 days of feeding, several fish (Group A) fed well on artificial diets during the whole feeding period; the other fish (Group B) fed well on artificial diets at the beginning of the feeding period, with their food intake then decreasing to half (anorexia) and then to zero for 5 days; and, finally, a negative control (Group C) fed on live prey fish throughout the experimental process. The plasma glucose was significantly higher in the mandarin fish of Group B than in those of Group A, whereas levels of hepatic glycogen and plasma triglyceride were significantly lower. Using transcriptome sequencing, we investigated the differentially expressed genes between Groups A and B and excluded the genes that were not differentially expressed between Groups A and C. The activation of mTOR and Jak/STAT pathways were found in the mandarin fish with anorexia, which was consistent with the higher expression levels of pepck and pomc genes. We found a higher expression of histone methyltransferase setd1b gene and an increased histone H3 tri-methylated at lysine 4 (H3K4me3) in the fish of Group B. Furthermore, using ChIP assay and inhibitor treatment, we found that the up-regulated H3K4me3 could activate pepck expression, which might have contributed to the hyperglycemia and anorexia in the mandarin fish that fed on carbohydrate-rich diets. Our study initially indicated a link between histone methylation and pepck expression, which might be a novel regulatory mechanism of fish who are fed a carbohydrate-rich diet.

The melanocortin-4 receptor (MC4R) plays a critical role in the regulation of energy homeostasis in both mammals and fish. Several fish MC4Rs recently characterized have high constitutive activities, potentially associated with food intake and growth rate. In the present study, we systematically investigated the effects of four human MC4R (hMC4R) antagonists, including agouti-related peptide (AgRP), Ipsen 5i, ML00253764, and MCL0020, on the cAMP and ERK1/2 signaling of two fish MC4Rs: spotted scat (Scatophagus argus) MC4R (saMC4R) and grass carp (Ctenopharyngodon idella) MC4R (ciMC4R), with hMC4R as a control. We showed that both saMC4R and ciMC4R were constitutively active with significantly increased basal cAMP levels. AgRP acted as an inverse agonist in cAMP signaling pathway in both fish MC4Rs whereas MCL0020 functioned as an inverse agonist for ciMC4R but a weak neutral antagonist for saMC4R. Ipsen 5i and MCL0020 behaved as neutral allosteric modulators in the cAMP signaling of fish MC4Rs. The saMC4R and ciMC4R had similar basal pERK1/2 levels as hMC4R and the pERK1/2 levels of the two fish MC4Rs were significantly increased upon stimulation with all four ligands. In summary, our studies demonstrated the existence of biased signaling in fish MC4R. We also showed dramatic pharmacological differences of human and fish MC4Rs with synthetic ligands. Our data provided novel insights and led to a better understanding of fish MC4R pharmacology.

As a kind of biologically active molecule, hydroxyproline (Hyp) is abundant in fish meal (FM) but not in plant protein sources. It remains very challenging to replace FM with plant protein sources, particularly for carnivorous fish. This study aims to investigate the effect of dietary Hyp supplementation on Chinese perch (Siniperca chuatsi) fed with FM partially replaced by fermented soybean meal (FSM), with 46% FM as the positive control and 31% FM plus 15% FSM as the negative control. Based on the negative control diet, 0.5%, 1%, 1.5% and 2% of dietary crystal L-Hyp was supplemented to formulate four experimental diets, respectively. Although the replacement of 15% FM with FSM in the feed resulted in a significant decline in growth performance of Chinese perch, dietary supplementation of 1% Hyp could improve the growth performance with high mRNA levels of the gh and igf1 genes. Piecewise regression analysis revealed that a dietary level of 2.27% Hyp could achieve the maximum weight gain rate. With high mRNA levels of orexigenic genes (npy and agrp in the brain, and ghrelin in the gut) and low mRNA levels of anorexigenic genes (pomc and cart in the brain, and leptin-A in the liver), an appropriate level of Hyp could be added to the diet of Chinese perch as a food attractant to promote the appetite and increase food intake. Besides, partial replacement of FM with FSM might promote the deposition of amino acids in the muscle, which may not be affected by dietary supplementation of Hyp. Furthermore, dietary supplementation of Hyp affected the activity of prolyl hydroxylase (PHD) and the mRNA levels of type I collagen regulatory genes and coding genes of three prolyl 4-hydroxylase (P4H) isozymes in the muscle of Chinese perch to some extent. In addition, supplementation of an appropriate level of Hyp could significantly improve the collagen content and muscle quality (hardness, chewiness and springiness) of Chinese perch, which may greatly enhance its edible and nutritional values.

Host-probiotics of many fish species have not been applied due to the difficulty in isolation and functional verification, and some exogenous probiotics were confirmed to promote the growth performance of fish. Therefore, this study aims to screen the exogenous probiotics that can be used in the culture of Chinese perch and to explore their mechanism of action. Chinese perch were respectively fed with basal diet (CK) supplemented with Clostridium butyricum CB1 (C), Enterococcus faecalis EF1 (E), Bacillus subtilis BS1 (B), and Lactobacillus plantarum LP1 (L) at 1.0 × 108 CFU/g with equal amount for 8 weeks. After feeding, B group presented significantly higher abundance of Bacillus, Lactobacillus, and Paenibacillus, and L group displayed significantly higher abundance of Lactobacillus than CK group. Above increased probiotics species led to higher intestinal lipase activity in B group, intestinal protease activity in L group, and length of intestinal villi and thickness of intestinal wall in B and L groups through fermentation to reduce pH value and secretion of active substances, thus facilitating the nutrient absorption to improve the weight gain (WG). Additionally, B and L groups respectively exhibited higher abundance level of the infectious diseases-related pathway and lower abundance of Aeromonas, which was responsible for higher expression of pro-inflammatory cytokines (p65-NF-κB, IL-Iβ, TNFα, and PAI) and higher blood immune parameter levels (globulin (GLB), total protein (TP), and lysozyme activity (LZM)), eventually improving survival rate. E group significantly inhibited microbial diversity and abundance of Energy metabolism pathway and Amino acid metabolism pathway, which might the reason for the decrease in crude protein content in whole-fish. C groups significantly reduced the microbial diversity and the length of intestinal villi to affect the host's nutrient absorption efficiency, thus causing a decrease in growth performance. Moreover, the imperfection of intestinal villi may allow more LPS to penetrate into the blood, thereby down-regulating the immune status and inducing inflammation, ultimately reducing survival rate. Above results indicated that Bacillus subtilis BS1 and Lactobacillus plantarum LP1 might be used in aquaculture, and probiotics may affect growth performance and gut health by regulating gut microbiota.

The total steroidal saponins, particularly its major steroidal sapogenin (diosgenin), are the main active principles of fenugreek seed extract. In this study, an ethanol-salt aqueous two-phase system (ATPS) was explored for the purification of the total steroidal saponins, and the process conditions were optimized by response surface methodology (RSM). Under the optimized conditions, the RSM predicted recovery of the total steroidal saponins in the top phase of ATPS was 97.9%, which agreed with the average experimental recovery (98.3 ± 4.2% (n = 6)). Moreover, a rapid micellar electrokinetic chromatography (MEKC) method was developed for the determination of diosgenin from extracts. The diosgenin content in the ATPS top phase extract was 3-fold higher than that in crude extract, suggesting this ATPS having a great potential for purification pharmacological active ingredients from fenugreek seeds.

Aqueous two-phase system (ATPS) was used for simultaneous purification of glycyrrhizic acid (GA) and liquiritin (LQ) from crude extract of Chinese licorice root. It was revealed that 87% GA and 94%...

Taste receptors play important roles in perception of L-amino acids and feeding behavior. However, convincing evidence providing causal links between taste receptors and feeding habits is lacking. We generated two mutant lines with t1r1 deletion in zebrafish by CRISPR/Cas9 technology. t1r1 deletion eliminated sensitivity to alanine in zebrafish. Additionally, it did not affect feeding behavior of zebrafish supplied with habitual food such as Artemia salina, while significantly enhanced their acceptance of rejective food such as duckweed and plant-protein source diets. Furthermore, replacement of fish meal with plant protein in diets significantly suppressed transcript levels of orexigenic gene npy and increased mRNA expression levels of anorexigenic gene pomca in wild-type zebrafish but had no effect in t1r1−/− zebrafish. In addition, when fed with fish meal diet, transcript levels of npy and pomca were significantly different in t1r1−/− zebrafish compared with wild-type zebrafish. Overall, these findings suggested that T1R1 was indispensable for amino acid perception and significantly affected the feeding preference and habit in zebrafish.

Fe2+ is widely used in wastewater treatment and plays an important role in the anammox system. In this study, the effects of Fe2+ on the anammox system was investigated with 0, 1, and 5 mM Fe2+ in reactors. During the start-up, the nitrogen removal performance was changed significantly, the nitrogen removal efficiency and nitrogen removal rate reached 94% and 81.5 g N m−3 d−1 in the reactor, respectively, at the 1 mM Fe2+ after 63 days of operation. Moreover, the extracellular polymeric substances were improved, and showed linear correlation with Fe2+ concentration. The 16S metagenomic analysis proved that Fe2+ addition increased the relative abundances of anammox bacteria-Candidatus Brocadia than that of control. The results of RT-qPCR also indicated that Fe2+ oxidation activated the central metabolism by up-regulating the key functional genes (hdh and hao) in anammox bacteria. The difference between functional genes, and Candidatus Brocadia abundances in the sludge led to differences in ammonium removal efficiency and nitrite removal efficiency between all reactors, because Ca. Brocadia has great influence on anaerobic ammonium oxidation. ARE and NRE will be improved when the suitable amount of Fe2+ was added into the sludge. Overall, the anammox system can be quickly improved even at higher concentrations when the anammox consortium encounter with an appropriate amount of Fe2+.

The disease outbreak of Chinese perch poses a severe threat to aquaculture industry. To explore the relationship between microbial communities in farming water and those in the intestine, and to further reveal the relationship between fish disease and environmental microbes (internal and external environments), 16S rRNA were sequenced. Although the composition and abundance of bacterial phyla varied with month in water samples, Actinobacteria and Proteobacteria were always the top 2 dominant phyla. Furthermore, most dominant genera in water were not significantly affected by environmental factors and seasonal changes, but there were specific dominant genera for each month. Besides, most dominant genera in water were not pathogenic bacteria. The Chinese perch ponds often breakout disease in September. 16S rRNA of the gut samples from the diseased and healthy Chinese perch were sequenced. In September, high water temperature and high contents of nitrite and ammonia-N might be environmental factors causing the disease outbreak of Chinese perch. The gut samples presented similarity in the phylum categories between the diseased and healthy Chinese perch, but they exhibited different abundances of microbiota at phylum level. Fusobacteria (44 %) exhibited the highest abundance in diseased Chinese perch, whereas Firmicutes (58 %) displayed the highest abundance in healthy Chinese perch. In addition, Lactococcus were dominant genus in September water samples and gut samples from diseased fish, which might be the pathogenic bacteria to infect the Chinese perch. Our findings provide novel information for improving microbial communities in aquaculture environments.

A 10 week feeding trial was conducted to evaluate the effects of different dietary soybean oil (SO) levels on growth performance, fatty-acid composition and lipid deposition in viscera, histology and histochemistry of liver, intestine and hepatic-lipid metabolism-related gene expressions in pond loach Misgurnus anguillicaudatus juveniles. Misgurnus anguillicaudatus (mean ± s.d. mass 0·40 ± 0·01 g) were fed five experimental diets containing SO at different concentrations: 0, 20, 32, 56 and 100% SO and a diet containing 100% fish oil (100% FO). The mass gains and specific growth rates of M. anguillicaudatus fed 20% SO and 100% FO diets were significantly higher than those of the other groups (P

BACKGROUND The deficiency of family 5 endoglucanase (Cel5A) and family 6 cellobiohydrolase (Cel6A) has become a key limiting factor on cellulase enzymatic hydrolysis in bioprocessing of cellulosic biomass. To improve the production of Trichoderma reesei Cel5A / Cel6A, a Vitreoscilla hemoglobin (VHb) gene was tried to co-express extracellularly for the first time with Cel5A / Cel6A in P. pastoris GS115. RESULTS Newly constructed recombinant of co-expressing Cel5A / Cel6A extracellularly with VHb was consistent with the single expression at some key variables of culture condition, i.e., inoculum size, initial pH, culture temperature and methanol concentration. Comparing their single expression, the CMCase activity of co-expressed Cel5A and Cel6A enzymes enhanced by 40% and 30%, respectively. With high-cell-density fed-batch (HCDFB) fermentation, the co-expressed Cel5A enzyme activity was 366.8 U mL−1 with 4.3 g L−1 protein content and the Cel6A enzyme activity reached 1.3 U mL−1 with 2.23 g L−1 protein content. The two co-expressed enzyme activities were enhanced by 35% and 20%, respectively, as compared to the single expression. CONCLUSION VHb protein capable of binding oxygen can be successfully co-expressed extracellularly with other target proteins. The co-expression of VHb with recombinant Cel5A / Cel6A is efficient at improving oxygen-limited condition and thus enzyme production in both shake-flask and HCDFB fermentation.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), is an infectious disease found worldwide. Children infected with MTB are more likely to progress to active TB (ATB); however, the molecular mechanism behind this process has long been a mystery. We employed the label-free quantitative proteomic technology to identify and characterize differences in plasma proteins between ATB and latent TB infection (LTBI) in children. To detect differences that are indicative of MTB infection, we first selected proteins whose expressions were markedly different between the ATB and LTBI groups and the control groups (inflammatory disease control (IDC) and healthy control (HC) groups). A total of 521 proteins differed (> 1.5-fold or < 0.6-fold) in the LTBI group, and 318 proteins in the ATB group when compared with the control groups. Of these, 49 overlapping proteins were differentially expressed between LTBI and ATB. Gene Ontology (GO) analysis revealed most proteins had a cellular and organelle distribution. The MTB infection status was mainly related to differences in binding, cellular and metabolic processes. XRCC4, PCF11, SEMA4A and ATP11A were selected and further verified by qPCR and western blot. At the mRNA level, the expression of XRCC4, PCF11and SEMA4A presented an increased trend in ATB group compare with LTBI. At the protein level, the expression of all these proteins by western blot in ATB/LTBI was consistent with the trends from proteomic detection. Our results provide important data for future mechanism studies and biomarker selection for MTB infection in children.

A feeding trial was conducted for 8 weeks to evaluate the effects of supplemental phytic acid (PA) on the apparent digestibility and utilization of dietary amino acids (AAs) and minerals in juvenile grass carp. Five experimental diets consisted of graded levels of PA (0.2, 4.7, 9.5, 19.1 and 38.3 g kg−1, named as P0, P5, P10, P20 and P40). Triplicate groups of fish (initial weight, 22.37 ± 0.16 g) were fed twice daily (08:00 and 16:00 h). The crude protein content in whole body significantly (p 4.7 g kg−1) significantly reduced the apparent digestibility coefficient (ADC) of AAs (Asp, Thr, Ser, Glu, Gly, Ala, Cys, Val, Met, Ile, Leu, Phe, Lys, Pro, His and Arg) and the ADC of minerals (P, Ca, Mg, Zn, Cu, Fe and Mn) in grass carp. The contents of minerals (P, Ca, Mg and Zn) in whole body and bone were also found to be significantly reduced in dietary PA > 4.7 g kg−1, while the bone ash, serum Alkp and Zn contents were found to be significantly decreased when the PA supplementation level was above 9.5 g kg−1, and the contents of serum Ca and Mg were found to be markedly altered in higher PA-supplemented groups. The results indicated that supplemental PA decreased the apparent digestibility and utilization of AAs and minerals, and thus reduced the feed utilization of grass carp, suggesting that the level of total PA should be below 4.7 g kg−1 in grass carp diet.

Failing to initiate first feeding during the transition from endogenous nutrition to exogenous feeding will lead to starvation of fish larvae. However, little is known about the mechanism of first feeding selection of fish. Golden mandarin fish larvae (3 d after hatch, 2.05 ± 0.03 mg) were fed with four different foods for 7 d, including the following: M – Megalobrama amblycephala (prey fish larvae as natural food); S – surimi of M. amblycephala; A – Artemia (zooplankton); and MA –mixed M. amblycephala with Artemia (mixed food). Larvae fed with the mixed food achieved an appropriate balance between high survival and good growth through elevating the expression of growth genes (GH, IGF-I, and IGF-II) and fatty acid synthesis genes (FAD and ELO). Growth performance of fish fed with MA reared at different salinities (0, 5, and 10 ppt) was examined. The salinity of 5 ppt produced the best growth performance of the three salinity levels tested. Fish larvae adapted to high- or low-salinity environments through increasing the expression of lipolysis genes (HSL, LPL, and HL). Therefore, both food type and salinity affect the growth, survival, and lipometabolism of golden mandarin fish larvae during initial feeding stage, and mixed food and 5 ppt salinity improved its survival and growth.

Summary The Chinese perch Siniperca knerii Garman, 1912 is an endemic perciform freshwater fish species mainly distributed in the Yangtze River and the Pearl River of China. To evaluate their genetic diversity in these rivers, microsatellite markers were used to assess the genetic structure and genetic variability among nine wild populations of S. knerii. In this study, the 12 loci used were polymorphic, with observed heterozygosity (Ho) ranging from 0.4079 to 0.8886 and polymorphism information content (PIC) ranging from 0.4511 to 0.7146. Results showed that six populations from the Yangtze River had a higher genetic diversity than those from the three Pearl River populations. The Bayesian STRUCTURE analysis recovered genetic clusters that matched localities perfectly or the kind of ecology environment with a significant Fst between them. The findings of this research should provide useful information for management and conservation of S. knerii stocks.

Summary The present study was conducted to characterize the proximate composition and fatty/amino acid profile in muscle, liver and gonads obtained from farmed male and female Chinese sturgeon (Acipenser sinensis) with gonad development at stage II, and to discern the key nutrients for gonads by comparing the nutrients between tissues and between fish at different gonad stages. Chinese sturgeon were reared in an outdoor circular cement pool at temperatures ranging from 8°C to 26°C, and fed with 70% artificial diets and 30% frozen forage fish at a feeding rate of 0.2%–1.5% body weight according to the water temperature. Three male and three female A. sinensis were sampled for analyses. Results showed that the lipid content in gonads was significantly higher than in other tissues in both males and females (p

Potato pulp, which is the industrial residue of potato processing for starch production, can be used for biochemicals production. In this study, a green, sustainable, highly productive technology for producing gluconic acid from potato pulp was developed. The cocktails of cellulases from Trichoderma reesei TX and Penicillum oxalicum JUA10–1 with commercial pectinase were prepared and used to hydrolyze hydrothermally treated potato pulp into fermentable sugars at a solids content of 25% (w/v). Eighty percent of the glucan in the potato pulp was able to be converted into glucose when 8 FPU/g of dry material (DM) of cellulase and 1000 PGU/g DM of pectinase were added. The enzymatic hydrolysates of the potato pulp were fermented into 81.4 g/L gluconic acid by Gluconobacter oxidans DSM 2003 for 20 h at 30 °C. The overall conversion yield from glucose to gluconic acid was 94.9%, and the productivity was 4.07 g/L/h, which was significantly better than that of previous studies. Finally, 546.48 g of gluconic acid ...

Gluconeogenesis responses was assessed during a short starvation period and subsequent refeeding in Siberian sturgeon (Acipenser baerii) previously fed different dietary carbohydrates levels and experienced to a glucose stimuli during early life. The sturgeon larvae were previously fed either a high glucose diet (G) or a low glucose diet (F) from the first feeding to yolk absorption (8 to 12 d post-hatching [dph]). Each group of fish was sub-divided into 2 treatments at 13 dph and was fed either a high-carbohydrate diet (H) or a low carbohydrate diet (L) until 20 wk. In the current study, the fish in 4 groups (GL, FL, GH and FH) were experienced to starvation for 21 d following by re-feeding of their corresponding diets for 21 d. Fish were sampled at postprandial 6 and 24 h before starvation (P6h and P24h), starvation 7, 14 and 21 d (S7, S14 and S21) and 1, 7, 14 and 21 d during refeeding (R1, R7, R14 and R21). Plasma samples during refeeding were taken at P6h at each time point. Glycaemia levels, liver and muscle glycogen contents, activities and mRNA levels of hepatic gluconeogenic enzymes were examined. We found that both dietary carbohydrate levels and early glucose stimuli significantly affected the metabolic responses to starvation and refeeding in Siberian sturgeon (P < 0.05). During prolonged starvation, Siberian sturgeon firstly mobilized the liver glycogen and then improved gluconeogenesis when the dietary carbohydrates were abundant, whereas preserved the liver glycogen stores at a stable level and more effectively promoted gluconeogenesis when the dietary carbohydrates are absent to maintain glucose homoeostasis. During refeeding, as most teleostean, Siberian sturgeon failed controlling the activities and mRNA levels of phosphoenolpyruvate carboxykinase cytosolic forms (PEPCK-C), fructose-1,6-bisphosphatase (FBPase), but particularly controlled phosphoenolpyruvate carboxykinase mitochondrial forms (PEPCK-M) activities and mRNA expression of glucose-6-phosphatase (G6Pase, except in GL group). Siberian sturgeon has a full compensatory ability on growth, but this ability would be obstructed by early glucose stimuli when refeeding the low carbohydrate diet after S21.

Melanocortin-4 receptor (MC4R) plays a pivotal role in the mediation of leptin action on food intake and energy expenditure in mammals. The MC4R has also been identified in several teleosts, and its importance in the regulation of fish energy homeostasis is emerging. We herein reported on the molecular cloning, tissue distribution, and pharmacological characterization of MC4R in grass carp (Ctenopharyngodon idella), an economically and ecologically important fish. We showed that grass carp MC4R (ciMC4R) consisted of a 981 bp open reading frame encoding a protein of 326 amino acids, highly homologous (>95%) to several teleost MC4Rs. Phylogenetic and synteny analysis further indicated ciMC4R was closely related to piscine MC4Rs. Using reverse transcription PCR, we found that mc4r messenger RNA was expressed in the brain as well as various peripheral tissues in grass carp. The pharmacological properties of ciMC4R were investigated using 4 agonists, including α-melanocyte stimulating hormone (α-MSH), β-MSH, [Nle4, D-Phe7]-MSH (NDP-MSH), and adrenocorticotropic hormone (ACTH). We showed that all 4 ligands could bind to ciMC4R and initiate dose-dependent intracellular cyclic adenosine monophosphate (cAMP) accumulation. Grass carp MC4R had the highest affinity for NDP-MSH. Both NDP-MSH and ACTH (1-24) exhibited higher potencies compared to the other 2 endogenous agonists. The ciMC4R was constitutively active, with significantly increased basal cAMP level compared with that of human MC4R (P < 0.01). The availability of ciMC4R and its pharmacologic characteristics provide a basis for future investigation of its functional roles in regulating diverse physiological processes and novel insights into understanding the mechanism of food habit transition in grass carp.

Background Despite being the most important cellulase producer, the cellulase-regulating carbon source signal transduction processes in Trichoderma reesei are largely unknown. Elucidating these processes is the key for unveiling how external carbon sources regulate cellulase formation, and ultimately for the improvement of cellulase production and biofuel production from lignocellulose. Results In this work, the role of the mitogen-activated protein kinase (MAPK) signal transduction pathways on cellulase formation was investigated. The deletion of yeast FUS3-like tmk1 in T. reesei leads to improved growth and significantly improved cellulase formation. However, tmk1 deletion has no effect on the transcription of cellulase-coding genes. The involvement of the cell wall integrity maintenance governing yeast Slt2-like Tmk2 in cellulase formation was investigated by overexpressing tmk3 in T. reesei Δtmk2 to restore cell wall integrity. Transcriptional analysis found little changes in cellulase-coding genes between T. reesei parent, Δtmk2, and Δtmk2::OEtmk3 strains. Cell wall integrity decreased in T. reesei Δtmk2 over the parent strain and restored in Δtmk2::OEtmk3. Meanwhile, cellulase formation is increased in T. reesei Δtmk2 and then decreased in T. reesei Δtmk2::OEtmk3. Conclusions These investigations elucidate the role of Tmk1 and Tmk2 on cellulase formation: they repress cellulase formation, respectively, by repressing growth and maintaining cell wall integrity, while neither MAPK regulates the transcription of cellulase-coding genes. This work, together with the previous investigations, suggests that all MAPKs are involved in cellulase formation, while Tmk3 is the only MAPK involved in signal transduction for the regulation of cellulase expression on the transcriptional level.

Preproghrelin, a gut/brain peptide, plays an important role in the regulation of food intake and energy homeostasis in teleost and mammals. In the present study, we obtained the full-length preproghrelin cDNA in Chinese perch. The preproghrelin messenger RNA (mRNA) tissue expression showed that level was much higher in stomach and pituitary than in other tissues. The fasting study showed, after gastric emptying (3-6 h), short-term fasting (6-12 h) increased preproghrelin expression in the stomach. While in the pituitary, fasting reduced preproghrelin expression at 1, 3, 12, and 48 h, presenting state fluctuation of self-adjustment. The temperature study showed that the mRNA expression of preproghrelin was the highest in the brain at 26 °C and highest in the stomach at 32 °C, respectively, with different optimum temperature in these two tissues, reflecting spatiotemporal differences of regulation by central nervous system and peripheral organs. The photoperiod study showed that normal light (11 h of lightness and 13 h of darkness) led to highest preproghrelin expression, both in the brain and in the stomach, than continuous light or continuous dark, proving food intake is adapted to natural photoperiod or normal light in this study. These results all indicated that tissue-specific preproghrelin expression of Chinese perch could be significantly affected by environmental factors. Short-term fasting of 6 h after gastric emptying, 26 °C, and normal light led to higher preproghrelin expression, which indicated potential appetite increase in Chinese perch.