TOR Signaling Pathway Research Articles

New perspective into possible mechanism in growth promotion of potassium diformate (KDF) on the juvenile grass carp (Ctenopharyngodon idella)

The present study was mainly designed to evaluate the effect of potassium diformate (KDF) on growth performance, digestion and absorption capacity and intestinal microbes of juvenile grass carp (Ctenopharyngodon idella). Six experimental diets with KDF 0.0, 1.5, 3.0, 4.5, 6.0 and 7.5 g/kg were respectively fed to 1620 fish (5.73 ± 0.01 g) for 70 days. Results indicated that dietary KDF addition improved growth performance, intestinal growth and development, digestive enzymes and brush border enzymes activity. Additionally, mRNA levels of most amino acid transporters (AATs) and peptide transporter 1 (PepT1), and protein expressions of SLC7A1, SLC1A5 and SLC15A1 in intestine were up-regulated with addition of 3.0 g/kg KDF, which might be related to the activated TOR signaling pathway, as evident by the up-regulated mRNA levels of TOR and S6K1, the increased protein expression of phosphorylation TORSer2448, as well as the down-regulated mRNA level of 4EBP1. Furthermore, the 16S rRNA sequencing revealed that low dose of KDF addition enriched the abundances of Fusobacteria and Cetobacterium, and reduced the abundances of Proteobacteria and Ralstonia, which might be related to the reduced pH of intestine. In a word, this study using grass carp as a model provided novel evidence on the positive role and possible mechanisms of KDF in promoting fish growth.

Effects of dietary α-ketoglutarate on the growth performance, digestive enzymes, tor signaling pathway and intestinal microbiota of juvenile mirror carp (Cyprinus carpio) fed low phosphorus diets

The present study evaluated the effects of dietary α-ketoglutarate (AKG) on the growth performance, digestive enzymes, target of rapamycin (tor) signaling pathway and intestinal microbiota of juvenile mirror carp (Cyprinus carpio) fed low phosphorus diets. An eight week 2 × 3 two-factorial experiment was conducted to investigate the interaction between AKG levels at 0 or 0.6%, and dietary phosphorus levels at 0.27%, 0.55% or 0.76%. The results showed that the final body weight (FBW) and weight growth rate (WGR) were significantly improved and the feed conversion ratio (FCR) was significantly decreased by the dietary AKG or phosphorus (P < 0.05). The crude ash and phosphorous content were significantly increased with increasing available phosphorus supplement from 0.27% to 0.76%, whereas crude lipid was decreased as dietary phosphorus levels increased (P < 0.05). Fish fed a diet supplemented with 0.6% AKG showed a significant increase in crude protein, crude ash and phosphorous content compared to the diet without AKG group (P < 0.05). The mRNA expression of IIb sodium-dependent phosphate cotransporter (NaPi-IIb) was decreased by dietary AKG or phosphorus (P < 0.05).The activities of trypsin was significantly improved by dietary AKG or phosphorus (P < 0.05). The mRNA expression of tor, insulin growth factor I (igfI) and growth hormone (gh) were significantly increased by dietary AKG or phosphorus (P < 0.05). The richness estimate of Ace and Chao, and the diversity estimators of Simpson were significantly decreased with increasing phosphorus levels from 0.27% to 0.55% (P < 0.05). Compared with the 0.27% phosphorus group, the abundance of Fusobacteriota and Bacteroidota were relatively increased and the abundance of Proteobacteria, Actinobacteriota and Cyanobacteria were relatively decreased in 0.27% phosphorus added 0.6% AKG group. The abundance of Fusobacteriota and Actinobacteriota in 0.27% phosphorus group was relatively lower than that in 0.55% phosphorus group. On the contrary, the abundance of Firmicutes, Bacteroidota and Cyanobacteria in 0.27% phosphorus group was relatively higher than that in 0.55% phosphorus groups. These results indicated that dietary supplementation with 0.6% AKG could improve growth performance by increasing the activities of trypsin and promoting the formation of beneficial intestinal microbiota, and the tor, gh/igf-I gene expression in liver of mirror carp fed low phosphorus diets.

Trehalose metabolism targeting as a novel strategy to modulate acid tolerance of yeasts and its application in food industry

Some spoilage yeasts are able to develop resistance to commonly used weak-acid preservatives. We studied the trehalose metabolism and its regulation in Saccharomyces cerevisiae in response to propionic acid stress. We show interruption of trehalose synthetic pathway caused the mutant hypersensitive to the acid stress, while its overexpression conferred acid-tolerance to yeast. Interestingly, this acid-tolerance phenotype was largely independent of trehalose but relied on the trehalose synthetic pathway. We demonstrate trehalose metabolism played a vital role in regulation of glycolysis flux and Pi/ATP homeostasis in yeast during acid-adaptation, and the PKA and TOR signaling pathways were involved in regulating trehalose synthesis at transcriptional level. This work confirmed the regulatory function of trehalose metabolism and improved our understanding of molecular mechanism of acid-adaptation of yeast. By exemplifying trehalose metabolism interruption limited the growth of S. cerevisiae exposed to weak acids, and trehalose pathway overexpression conferring acid-resistance to Yarrowia lipolytica enhanced citric acid production, this work provides new insights into the development of efficient preservation strategies and robust organic acid producers.

Angelica sinensis polysaccharide extends lifespan and ameliorates aging-related diseases via insulin and TOR signaling pathways, and antioxidant ability in Drosophila

Angelica sinensis polysaccharide (ASP) is one of the principal active components of Angelica sinensis (AS) that is widely used in natural medicine and has various pharmacological activities, including antioxidant, anti-inflammatory, and enhancing immunity. However, its pharmacological role of anti-aging needs to be clarified. Here, we detected the beneficial effect and mechanism of ASP on healthy aging and aging-related diseases using the Drosophila melanogaster model. The results showed that oral administration of ASP remarkably extended lifespan, increased reproduction, improved climbing ability, and increased resistance to starvation and oxidative stress in aged flies, mainly via inhibiting insulin signaling (IIS) and TOR signaling and boosting antioxidant ability. Further, ASP supplementation protected against aging-induced intestinal homeostasis imbalance via inhibiting intestinal stem cells (ISCs) hyperproliferation and oxidative damage, improved sleep disorders via rescuing sleep rhythm in aged flies, and had a neuroprotective effect on Aβ42 transgenic flies. Taken together, our findings shed light on the possibility that ASP could increase lifespan, improve healthy aging, and ultimately reduce the incidence of age-related illnesses. It holds promise as a candidate for anti-aging intervention and treatment for aging-associated disorders.

A novel gene REPTOR2 activates the autophagic degradation of wing disc in pea aphid.

Wing dimorphism in insects is an evolutionarily adaptive trait to maximize insect fitness under various environments, by which the population could be balanced between dispersing and reproduction. Most studies concern the regulatory mechanisms underlying the stimulation of wing morph in aphids, but relatively little research addresses the molecular basis of wing loss. Here, we found that, while developing normally in winged-destined pea aphids, the wing disc in wingless-destined aphids degenerated 30-hr postbirth and that this degeneration was due to autophagy rather than apoptosis. Activation of autophagy in first instar nymphs reduced the proportion of winged aphids, and suppression of autophagy increased the proportion. REPTOR2, associated with TOR signaling pathway, was identified by RNA-seq as a differentially expressed gene between the two morphs with higher expression in the thorax of wingless-destined aphids. Further genetic analysis indicated that REPTOR2 could be a novel gene derived from a gene duplication event that occurred exclusively in pea aphids on autosome A1 but translocated to the sex chromosome. Knockdown of REPTOR2 reduced autophagy in the wing disc and increased the proportion of winged aphids. In agreement with REPTOR's canonical negative regulatory role of TOR on autophagy, winged-destined aphids had higher TOR expression in the wing disc. Suppression of TOR activated autophagy of the wing disc and decreased the proportion of winged aphids, and vice versa. Co-suppression of TOR and REPTOR2 showed that dsREPTOR2 could mask the positive effect of dsTOR on autophagy, suggesting that REPTOR2 acted as a key regulator downstream of TOR in the signaling pathway. These results revealed that the TOR signaling pathway suppressed autophagic degradation of the wing disc in pea aphids by negatively regulating the expression of REPTOR2.

A ginseng-derived rhamnogalacturonan I (RG-I) pectin promotes longevity via TOR signalling in Caenorhabditis elegans

Panax ginseng C. A. Meyer (ginseng), a traditional Chinese herb, is usually used to improve health and increase anti-aging activity for human. Polysaccharides are bioactive components of ginseng. Herein, using Caenorhabditis elegans as a model, we discovered a ginseng-derived rhamnogalacturonan I (RG-I) pectin WGPA-1-RG promoted longevity via TOR signalling pathway with transcription factors FOXO/DAF-16 and Nrf2/SKN-1 accumulated in the nucleus, where they activated target genes. And the WGPA-1-RG-mediated lifespan extension was dependent on endocytosis, rather than a bacterial metabolic process. Glycosidic linkage analyses combined with arabinose- and galactose-releasing enzyme hydrolyses identified the RG-I backbone of WGPA-1-RG was primarily substituted with α-1,5-linked arabinan, β-1,4-linked galactan and arabinogalactan II (AG-II) side chains. Feeding worms with the WGPA-1-RG-derived fractions which lost distinct structural elements by enzymatic digestions, we found the arabinan side chains prominently contributed to the longevity-promoting activity of WGPA-1-RG. These findings provide a novel ginseng-derived nutrient that potentially increases human longevity.

A lipid droplet-associated protein Nem1 regulates appressorium function for infection of Magnaporthe oryzae

Lipid droplets are important storages in fungal conidia and can be used by plant pathogenic fungi for infection. However, the regulatory mechanism of lipid droplets formation and the utilization during fungal development and infection are largely unknown. Here, in Magnaporthe oryzae, we identified a lipid droplet-associated protein Nem1 that played a key role in lipid droplets biogenesis and utilization. Nem1 was highly expressed in conidia, but lowly expressed in appressoria, and its encoded protein was localized to lipid droplets. Deletion of NEM1 resulted in reduced numbers of lipid droplets and decreased content of diacylglycerol (DAG) or triacylglycerol (TAG). NEM1 was required for asexual development especially conidia production. The Δnem1 mutant was nearly loss of virulence to host plants due to defects in appressorial penetration and invasive growth. Remarkably, Nem1 was regulated by the TOR signaling pathway and involved in the autophagy process. The Ser303 residue of Nem1 could be phosphorylated by the cAMP-PKA signaling pathway and was important for biological function of Nem1. Together, our study revealed a regulatory mechanism of lipid biogenesis and metabolism during the conidium and appressorium formation of the rice blast fungus.

Molecular signatures of diapause in the Asian longhorned beetle: Gene expression.

Most previous studies on gene expression during insect diapause do not address among-tissue variation in physiological processes. We measured transcriptomic changes during larval diapause in the Asian longhorned beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae). We conducted RNA-seq on fat body, the supraesophageal ganglion, midgut, hindgut, and Malpighian tubules during pre-diapause, diapause maintenance, post-diapause quiescence, and post-diapause development. We observed a small, but consistent, proportion of genes within each gene expression profile that were shared among tissues, lending support for a core set of diapause-associated genes whose expression is tissue-independent. We evaluated the overarching hypotheses that diapause would be associated with cell cycle arrest, developmental arrest, and increased stress tolerance and found evidence of repressed TOR and insulin signaling, reduced cell cycle activity and increased capacity of stress response via heat shock protein expression and remodeling of the cytoskeleton. However, these processes varied among tissues, with the brain and fat body appearing to maintain higher levels of cellular activity during diapause than the midgut or Malpighian tubules. We also observed temperature-dependent changes in gene expression during diapause maintenance, particularly in genes related to the heat shock response and MAPK, insulin, and TOR signaling pathways. Additionally, we provide evidence for epigenetic reorganization during the diapause/post-diapause quiescence transition and expression of genes involved in post-translational modification, highlighting the need for investigations of the protein activity of these candidate genes and processes. We conclude that diapause development is coordinated via diverse tissue-specific gene expression profiles and that canonical diapause phenotypes vary among tissues.

Capsaicin decreases fecundity in the Asian malaria vector Anopheles stephensi by inhibiting the target of rapamycin signaling pathway

BackgroundMosquito-borne diseases threaten human health, but mosquito control faces various challenges, such as resistance to chemical insecticides. Thus, there is an urgent need for more effective and environment-friendly control agents. Capsaicin can downregulate the mTOR signaling pathway of tumor cells. The TOR signaling pathway can mediate the expression of vitellogenin (Vg) to regulate the fecundity of insects. Whether capsaicin has the potential to inhibit fecundity of mosquitoes by regulating TOR pathway and Vg expression is currently unclear.MethodsAnopheles stephensi were fed with blood of mice administered capsaicin by gavage or sugar containing capsaicin followed by a blood feeding with normal mice. Then, the engorged female mosquitoes were tubed individually and underwent oviposition. The eggs and individuals in the subsequent development stages, including larvae, pupae, and emerging adults, were counted and compared between the capsaicin treatment and control groups. Additionally, total RNA and protein were extracted from the engorged mosquitoes at 24 h post blood feeding. Real-time PCR and western blot were performed to detect the transcriptional level and protein expression of the key fecundity-related molecules of mosquitoes. Finally, TOR signaling pathway was inhibited via rapamycin treatment, and changes in fecundity and the key molecule transcription and protein expression levels were examined to verify the role of TOR signaling pathway in the effect of capsaicin on mosquito fecundity.ResultsThe laid and total eggs (laid eggs plus retained eggs) of An. stephensi were significantly reduced by feeding on the blood of capsaicin-treated mice (P < 0.01) or capsaicin-containing sugar (P < 0.01) compared with those in the control group. Moreover, the transcription and protein expression or phosphorylation levels of fecundity-related molecules, such as Akt, TOR, S6K, and Vg, were significantly decreased by capsaicin treatment. However, the effects disappeared between control group and CAP group after the TOR signaling pathway was inhibited by rapamycin.ConclusionsCapsaicin can decrease the fecundity of An. stephensi by inhibiting the TOR signaling pathway. These data can help us to not only understand the effect of capsaicin on the reproductive ability of An. stephensi and its underlying mechanism, but also develop new efficient, safe, and pollution-free mosquito vector control agents.Graphical

Exploring the HSA/DNA/lung cancer cells binding behavior of p-Synephrine, a naturally occurring phenyl ethanol amine with anti-adipogenic activity: multi spectroscopic, molecular dynamic and cellular approaches

As a phenolic amine, p-Synephrine (SN) is known to exhibit lipolytic properties as well as enhancing energy expenditure, which can be an excellent alternative to ephedra as a dietary supplement. This study aimed to explore the subtle yet profound complex qualities and aspects of the interaction between SN, human serum albumin (HSA), and calf thymus DNA (ctDNA). To achieve a full comprehension on these fine-point distinctions, a nuanced and detail-oriented approach was implemented through a combination of different biophysical methods and molecular dynamics simulation techniques. The fluorescence spectroscopy revealed the binding of SN to HSA that led to the inducement of conformational changes. The quenching constants (KSV) of SN-HSA complex at 298, 303, and 308 K and were evaluated to be 2.95 × 104, 2.21 × 104 and 0.85 × 104 M−1, respectively. The thermodynamic parameters indicated the spontaneous formation of SN-HSA complex along with its regulation through H-bonding and van der Waals forces. The distance between SN and Trp residue of HSA was estimated at 3.91 nm by the Forster’s theory of non-radiative resonance energy transfer. According to CD spectroscopy, the binding of SN to HSA results in stabilization and promotes its functionality. Various spectroscopy methods and viscosity measurements proved the propensity of SN for binding to the grooves of ctDNA. Thermodynamic parameters indicate that the SN binds to DNA via a spontaneous and entropy-driven process that is mainly regulated by hydrophobic interactions. In conformity to the molecular modeling of HSA-SN complex, SN can be located in the active site of HSA and make a firm interaction, while the outcomes of ctDNA-SN interaction also indicated its tendency towards binding in DNA groove. In comparison to normal cells, SN caused a more pronounced reduction in lung cancer cell viability by increasing the expression of Bax and p53 at the mRNA and protein levels. Moreover, the incubation of H460 cells with the IC50 concentration of SN induced a notable decease in mRNA levels of PI3K, AKT, and mTOR, as well as protein levels of PI3Kγ-P110, P-AKT, and P-m TOR. These data indicate the potential of SN in binding with HSA, which reduces the proliferation of lung cancer cells mediated by apoptosis through the down regulation of PI3K/AKT/m TOR signaling pathway.

Leucine promotes protein synthesis of juvenile white shrimp Litopenaeus vannamei through TOR signaling pathway

Leucine is an essential amino acid for animal growth and development. However, the role of leucine in protein and glucose metabolism in crustaceans remains unclear. In this study, the effects of leucine on TOR pathway and glucose metabolism of Pacific white shrimp (Litopenaeus vannamei) were investigated by a feeding trial and an in vitro experiment. A total of 540 juvenile shrimps (0.67 ± 0.00 g) were randomly distributed into 18 tanks with 30 shrimps per tank. Shrimp were fed 6 diets with leucine levels of 2.10, 2.30, 2.50, 2.70, 2.90 and 3.10% respectively for 56 days (n = 3). The results showed that 2.50% leucine promoted muscle crude protein content, hepatopancreatic fibrillar cell number and area, and decreased serum and hepatopancreas glucose content. It was found that 2.50% leucine significantly up-regulated the expression levels of key genes in the TOR signaling pathway, including protein kinase B (akt), ras homologue enriched in brain (rheb), solute carrier family 3 member 2 (slc3a2), target of rapamycin (tor), regulatory-associated protein of mTOR (raptor), RPTOR independent companion of mTOR, Complex 2 (rictor), rhodopsin (rho), ribosomal protein S6 kinase (s6k) and eukaryotic translation initiation factor 4E 2 (eif4e2), but down-regulated the expression of tuberous sclerosis 2 (tsc2) and 4E-Binding protein (4e-bp) in hepatopancreas, which suggests that leucine may regulate protein deposition through TOR pathway. Similarly, the protein expression of Akt was also increased at 2.50% dietary leucine level. In addition, 2.50% dietary leucine level significantly increased the gene expressions of hexokinase (hk), pyruvate kinase (pk) and glucose transporter 2 (glut2), and down-regulated the gene expressions of pyruvate carboxylase (pc) and phosphoenolpyruvate carboxy kinase (pepck), which indicates appropriate leucine lowers glucose through glycolysis and gluconeogenesis pathway. Furthermore, the in vitro study showedthat 250 mg/L leucine supplement significantly increased hepatopancreas cell viability and up-regulated the expression levels of tor, akt, slc3a2, s6k, eif4e2, rictor, rho, hk, pk, pepck and glut2 compared with the control group (without leucine). The expression level of Sestrin (sesn) in hepatopancreas cells was down-regulated. These results suggest that appropriate dietary leucine supplementation can promote protein deposition of white shrimp, which may be attributed to the fact that leucine can maintain the structural integrity of hepatopancreas and improve protein synthesis and glucose utilization through TOR signaling pathway. The leucine requirement of Litopenaeus vannamei is estimated to be 2.60%–2.67% of the diet (6.67%–6.88% of dietary protein) according to the polynomial regression analysis of whole-body protein, muscle protein, hepatopancreas glucose and hepatopancreatic fibrillar cell number. These results will help us further understand the effects of leucine on growth and protein deposition in crustaceans.

Appropriate dietary phenylalanine improved growth, protein metabolism and lipid metabolism, and glycolysis in largemouth bass (Micropterus salmoides).

The purpose of this study was aimed to determine the appropriate level of dietary phenylalanine and explored the influences of phenylalanine on target rapamycin (TOR) signaling and glucose and lipid metabolism in largemouth bass. Six isonitrogenous/isoenergetic diets with graded phenylalanine levels (1.45% (control group), 1.69%, 1.98%, 2.21%, 2.48%, and 2.76%) were designed. Experimental feed was used to feed juvenile largemouth bass (initial body weight 19.5 ± 0.98g) for 8weeks. The final body weight, specific growth rate (SGR), feed efficiency ratio (FER), and weight gain (WG) reached their highest values in the 1.98% dietary phenylalanine group and then declined with increasing phenylalanine addition. No significant difference was found in the whole-body composition of largemouth bass between different dietary phenylalanine groups. Compared with the control group, 1.69% dietary phenylalanine significantly reduced the contents of plasma glucose (GLU) and total protein (TP), and total cholesterol (TC) contents increased significantly in the 1.98% dietary phenylalanine group (P < 0.05). The key gene expressions of TOR signaling pathway and lipid metabolism was significantly inhibited by 2.21% dietary phenylalanine (P < 0.05). The 1.98% dietary phenylalanine group showed significantly increased expression of genes related to insulin signaling pathway and factors involved in fatty acid synthesis (P < 0.05). Furthermore, 2.76% dietary phenylalanine group inhibited glucose metabolism by lowering the key gene expressions of glucose metabolism (P < 0.05). According to quadratic regression analyses based on the WG and FER, the appropriate level of dietary phenylalanine for largemouth bass were 2.00% and 2.02% of the diet (4.23% and 4.27% dietary protein), respectively, with a constant amount of tyrosine (1.33%). Hence, the total aromatic amino acid requirements were 3.33% and 3.35% of the diet (equivalent to 7.03% and 7.09% of the protein content), which may provide a theoretical basis for the development of largemouth bass feed formulas. Therefore, the growth and metabolism of largemouth bass could be promoted by controlling the content of phenylalanine in the diet, or the imbalance of phenylalanine can form a specific pathological model.

Dietary Histidine Supplementation Maintained Amino Acid Homeostasis and Reduced Hepatic Lipid Accumulation of Juvenile Largemouth Bass, Micropterus Salmoides.

This 56-day research aimed to evaluate the recommended histidine requirement and the influence of dietary histidine levels on the protein and lipid metabolism of juvenile largemouth bass (Mieropterus salmoides). The initial weight of the largemouth bass was 12.33 ± 0.01 g, which was fed with six graded levels of histidine. The results showed that appropriate dietary histidine had a positive effect on growth, with a higher specific growth rate, final weight, weight gain rate, protein efficiency rate, and a lower feed conversion rate and feed intake rate being observed in 1.08-1.48% dietary histidine groups. Furthermore, the mRNA levels of GH, IGF-1, TOR, and S6 showed an increasing trend first and then declined, similar to the trend of the growth and protein content of the whole body composition. Meanwhile, dietary histidine levels could be sensed by the AAR signaling pathway, representing as downregulation of core genes of AAR signaling pathway with the increased dietary histidine levels, including GCN2, eIF2α, CHOP, ATF4, and REDD1. In addition, increased dietary histidine levels decreased the lipid content of the whole body and the liver by upregulating the mRNA levels of core genes of the PPARα signaling pathways, including PPARα, CPT1, L-FABP, and PGC1α. However, increased dietary histidine levels downregulated the mRNA levels of core genes of the PPARγ signaling pathways such as PPARγ, FAS, ACC, SREBP1, and ELOVL2. These findings were also supported by the positive area ratio of hepatic oil red O staining and the TC content of plasma. According to the specific growth rate and feed conversion rate, the recommended histidine requirement of juvenile largemouth bass was 1.26% of the diet (2.68% of dietary protein) by regression lines calculated using a quadratic model. In general, histidine supplementation promoted protein synthesis and lipid decomposition and reduced lipid synthesis by activating the TOR, AAR, PPARα, and PPARγ signaling pathways, which provided a new perspective to solve the fatty liver problem of largemouth bass by nutritional means.

Dietary Aflatoxin B1 attenuates immune function of immune organs in grass carp (Ctenopharyngodon idella) by modulating NF-κB and the TOR signaling pathway.

Aflatoxin B1 (AFB1) is kind of a common mycotoxin in food and feedstuff. Aquafeeds are susceptible to contamination of AFB1. In teleost fish, the spleen and head kidney are key immune organ. Moreover, the fish skin is a critical mucosal barrier system. However, there was little study on the effects of dietary AFB1 on the immune response of these immune organs in fish. This study aimed to explore the impacts of oral AFB1 on the immune competence and its mechanisms in the skin, spleen, and head kidney of grass carp. Our work indicated that dietary AFB1 reduced antibacterial compounds and immunoglobulins contents, and decreased the transcription levels of antimicrobial peptides in grass carp immune organs. In addition, dietary AFB1 increased the transcription levels of pro-inflammatory cytokines and reduced the transcription levels of anti-inflammatory cytokines in the grass carp immune organs, which might be regulated by NF-κB and TOR signaling, respectively. Meanwhile, we evaluated the content of AFB1 in the grass carp diet should not exceed 29.48 μg/kg diet according to the levels of acid phosphatase and lysozyme. In summary, dietary AFB1 impaired immune response in grass carp skin, spleen, and head kidney.

A High-Copy Suppressor Screen Reveals a Broad Role of Prefoldin-like Bud27 in the TOR Signaling Pathway in Saccharomyces cerevisiae.

Bud27 is a prefoldin-like, a member of the family of ATP-independent molecular chaperones that associates with RNA polymerases I, II, and III in Saccharomyces cerevisiae. Bud27 and its human ortholog URI perform several functions in the cytoplasm and the nucleus. Both proteins participate in the TOR signaling cascade by coordinating nutrient availability with gene expression, and lack of Bud27 partially mimics TOR pathway inactivation. Bud27 regulates the transcription of the three RNA polymerases to mediate the synthesis of ribosomal components for ribosome biogenesis through the TOR cascade. This work presents a high-copy suppression screening of the temperature sensitivity of the bud27Δ mutant. It shows that Bud27 influences different TOR-dependent processes. Our data also suggest that Bud27 can impact some of these TOR-dependent processes: cell wall integrity and autophagy induction.

Production of the yolk protein precursor vitellogenin is mediated by target of rapamycin (TOR) in the soft tick Ornithodoros moubata (Acari: Argasidae).

Initiation of vitellogenesis by blood feeding is essential for egg maturation in ticks. Nutrients derived from the blood meal are utilized by female ticks to synthesize the yolk protein precursor vitellogenin (Vg). Engorged Ornithodoros moubata ticks can synthesize Vg whether mated or virgin, thus O. moubata is an excellent model for studying the relative roles of blood feeding and mating in tick vitellogenesis. Injection of rapamycin into engorged O. moubata resulted in a reduction of ovarian growth and yolk accumulation in the oocytes of mated females. OmVg expression in the midgut and fat body and protein concentrations in the hemolymph significantly decreased in mated ticks after injection with rapamycin, indicating that inhibition of the nutrient-sensing target of rapamycin (TOR) pathway disrupts egg maturation at the levels of Vg expression and synthesis. These results suggest that the TOR-signaling pathway induces vitellogenesis in response to nutritional stimulation after a blood meal in O. moubata and is functionally independent of the mating-induced pathway.

Comparative Gene Expression and Physiological Analyses Reveal Molecular Mechanisms in Wound-Induced Spore Formation in the Edible Seaweed Nori.

Genetic reprogramming of differentiated cells is studied broadly in multicellular Viridiplantae as an adaptation to herbivory or damage; however, mechanisms underlying cell development and redifferentiation are largely unknown in red algae, their nearest multicellular relatives. Here we investgate cell reprogramming in the widely cultivated, edible seaweed Neopyropia yezoesis (“nori”), where vegetative cells in wounded blades differentiate and release as large numbers of asexual spores. Based upon physiological changes and transcriptomic dynamics after wound stress in N. yezoensis and its congener Neoporphyra haitanensis, another cultivar that does not differentiate spores after wounding, we propose a three-phase model of wound-induced spore development in N. yezoensis. In Phase I, propagation of ROS by RBOH and SOD elicites systematic transduction of the wound signal, while Ca2+ dependent signaling induces cell reprogramming. In Phase II, a TOR signaling pathway and regulation of cyclin and CDK genes result in cell divisions that spread inward from the wound edge. Once sporangia form, Phase III involves expression of proteins required for spore maturation and cell wall softening. Our analyses not only provide the first model for core molecular processes controlling cellular reprogramming in rhodophytes, but also have practical implications for achieving greater control over seeding in commercial nori farming.

Complete Replacement of Fishmeal With Plant Protein Ingredients in Gibel Carp (Carassius auratus gibelio) Diets by Supplementation With Essential Amino Acids Without Negative Impact on Growth Performance and Muscle Growth-Related Biomarkers

This study was conducted to investigate the effects of substitution of dietary fishmeal (FM) by compound plant protein supplemented with essential amino acids on growth performance, plasma physiology, and muscle growth-related genes of gibel carp (Carassius auratus gibelio). Four diets with equal digestible protein were prepared, where 30FM (control feed) contained 30% FM and land animal protein as a protein source, 10FM contained 10% FM, PMAa contained full plant meal (PM) supplemented with crystalline amino acid, and PM contained full PM feed. There was no significant difference in the specific growth rate (SGR) with 30FM, 10FM, and PMAa diets (p &amp;gt; 0.05); however, the SGR of PM group was the lowest with significant difference (p &amp;lt; 0.05). Feed efficiency of the PM group was the lowest with significant difference (p &amp;lt; 0.05). The whole-body crude protein content of fish in PMAa group was significantly higher than that in each group with additional FM (p &amp;lt; 0.05). There were no significant differences in plasma total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C), and free amino acid profile of 30FM, 10FM, and PMAa groups (p &amp;gt; 0.05); however, they were significantly higher than that in PM group (p &amp;lt; 0.05). The expression of key genes in the TOR signaling pathway (tor, s6k1, 4e-bp2, and eif4e), autophagy (ulk1 and atg13), and ubiquitin–proteasome (trim63 and znrf2) system of the PMAa group was similar to that of the FM group (p &amp;gt; 0.05), indicating that the muscle growth-related biomarker genes were positively regulated by the appropriate dietary amino acid composition at the transcriptional level. These results suggest that FM in gibel carp diet can be totally replaced by PM without negative impact on growth performance and muscle growth-related biomarkers at the transcriptional level, which provided the requirement of digestible protein and balanced amino acid profile is satisfied.

Translational control of E2f1 regulates the Drosophila cell cycle

E2F transcription factors are master regulators of the eukaryotic cell cycle. In Drosophila, the sole activating E2F, E2F1, is both required for and sufficient to promote G1→S progression. E2F1 activity is regulated both by binding to RB Family repressors and by posttranscriptional control of E2F1 protein levels by the EGFR and TOR signaling pathways. Here, we investigate cis-regulatory elements in the E2f1 messenger RNA (mRNA) that enable E2f1 translation to respond to these signals and promote mitotic proliferation of wing imaginal disc and intestinal stem cells. We show that small upstream open reading frames (uORFs) in the 5' untranslated region (UTR) of the E2f1 mRNA limit its translation, impacting rates of cell proliferation. E2f1 transgenes lacking these 5'UTR uORFs caused TOR-independent expression and excess cell proliferation, suggesting that TOR activity can bypass uORF-mediated translational repression. EGFR signaling also enhanced translation but through a mechanism less dependent on 5'UTR uORFs. Further, we mapped a region in the E2f1 mRNA that contains a translational enhancer, which may also be targeted by TOR signaling. This study reveals translational control mechanisms through which growth signaling regulates cell cycle progression.

Adenovirus vector encoding TPPII ignites HBV-specific CTL response by activating autophagy in CD8+ T cell.

Early studies have shown that autophagy and TPPII are associated with HBV infection. In this study, adenovirus vector containing TPPII was constructed to immunize HBV transgenic mice in vivo to explore the potential mechanism of autophagy and HBV infection. Our goal is to provide new ideas for immunotherapy of hepatitis B. First, adenovirus vector containing TPPII was constructed. Then, we used adenovirus to immunize HBV transgenic mice and ATG5knockout HBV transgenic mice. The autophagy of CD8+ T cells was detected by transmission electron microscopy and immunofluorescence electron microscopy, Western blot was used to detect the expression of autophagy LC3 and BECN1, CTL reaction, HBV DNA and HBsAg in serum, HBsAg and HBcAg in liver tissues by immunohistochemistry, to further examine the possible mechanisms involved in autophagy. Adv-HBcAg-TPPII promotes autophagy of CD8+ T lymphocyte, activates CTL response, inhibits HBV DNA replication and HBsAg expression, and PI3K/ Akt /m TOR signalling pathway may be involved in autophagy. This study demonstrates that autophagy of CD8+ T cells was induced by Adv-HBcAg-TPPII and the molecular mechanism may be related to the PI3K/ Akt /m TOR signalling pathway, providing a possible theoretical basis for immunotherapy of hepatitis B.