Identification and expression analysis of two steamer-like retrotransposons in the Chilean blue mussel (Mytilus chilensis).

BACKGROUND: Disseminated neoplasia (DN) is a proliferative cell disorder of the circulatory system of bivalve mollusks. The disease is transmitted between individuals and can also be induced by external chemical agents such as bromodeoxyuridine. In Mya arenaria, we have cloned and characterized an LTR-retrotransposon named Steamer. Steamer mRNA levels and gene copy number correlates with DN and can be used as a marker of the disease. So far, the only mollusk where a retrotransposon expression relates to DN is Mya arenaria. On the other hand, it has been reported that the Chilean blue mussel Mytilus chilensis can also suffers DN. Our aim was to identify retrotransposons in Mytilus chilensis and to study their expression levels in the context of disseminated neoplasia. RESULTS: Here we show that 7.1% of individuals collected in August 2018, from two farming areas, presents morphological characteristics described in DN. Using Steamer sequence to interrogate the transcriptome of M. chilensis we found two putative retrotransposons, named Steamer-like elements (MchSLEs). MchSLEs are present in the genome of M. chilensis and MchSLE1 is indeed an LTR-retrotransposon. Neither expression, nor copy number of the reported MchSLEs correlate with DN status but both are expressed at different levels among individual animals. We also report that in cultured M. chilensis haemocytes MchSLEs1 expression can be induced by bromodeoxyuridine. CONCLUSIONS: We conclude that SLEs present in Mytilus chilensis are differentially expressed among individuals and do not correlate with disseminated neoplasia. Treatment of haemocytes with a stressor like bromodeoxyuridine induces expression of MchSLE1 suggesting that in Mytilus chilensis environmental stressors can induce activation of LTR-retrotransposon.

Early regulation of corticosteroid receptor expression in rainbow trout (Oncorhynchus mykiss) gills is mediated by membrane-initiated cortisol signaling.

Cortisol is a key stress-related hormone involved in the physiological adjustments of fish. In gills, cortisol contributes to acclimatization to changes in environmental salinity, promoting both ion uptake or salt excretion. Cortisol exerts its biological effects through its interaction with specific intracellular glucocorticoid (GR) and mineralocorticoid (MR) receptors. Additionally, the further identification of GR and MR on the surface of different tissues, together with the existence of cortisol-mediated effects observed using membrane-impermeable analogs (e.g., cortisol-BSA), supports the existence of membrane-initiated cortisol actions in fish. Nevertheless, the impact of this alternative cortisol mechanism in relevant tissues for fish salinity acclimation, such as gill, is unknown. In this work, we sought to explore the contribution of rapid membrane-initiated cortisol on GR and MR regulation in rainbow trout (Oncorhynchus mykiss) gills using in vivo and in vitro approaches. Juvenile rainbow trout intraperitoneally injected with cortisol or cortisol-BSA showed increased gr2 but no gr1 or mr mRNA levels in gills after one hour of treatment. This result was further confirmed using RT-gills-W1 cell lines stimulated with both versions of cortisol. Interestingly, after three and six hours of cortisol or cortisol-BSA treatment, there were no changes in the mRNA levels of any corticosteroid receptor in RT-gills-W1 cells. Finally, using immunofluorescence analysis, we identified GR and MR in rainbow trout gill cells localized on the cell surface. Considering the in vivo and in vitro results of this work, we suggest that membrane-initiated cortisol action contributes to the early expression of gr2 in rainbow trout gills during salinity acclimation.

Sorghum (Sorghum bicolor L.) as a potential source of bioactive substances and their biological properties.

Sorghum is the fifth cereal most produced in the world after wheat, rice, maize, and barley. In some regions, this crop is replacing maize, due to its high yield, resistance to drought and heat. There are several varieties of sorghum, whose coloration varies from cream, lemon-yellow, red, and even black. Pigmented sorghum grain is a rich source of antioxidants like polyphenols, mainly tannins, which have multiple benefits on human health such as, antiproliferative properties associated with the prevention of certain cancers, antioxidant activities related to the prevention of associated diseases to oxidative stress, antimicrobial and anti-inflammatory effects, it also improves glucose metabolism. Despite having these types of compounds, it is not possible to assimilate them, their use in the food industry has been limited, since sorghum is considered a food of low nutritional value, due to the presence of anti-nutritional factors such as strong tannins which form complexes with proteins and iron, thus reducing their digestibility. Based on these restrictions that this product has had as food for humans, the analysis of this review emphasizes the valorization of sorghum as a source of bioactive substances and the importance they confer on human health because of the biological potential it has.

Recovery of Bioactive Ellagitannins by Ultrasound/Microwave-Assisted Extraction from Mexican Rambutan Peel (Nephelium lappaceum L.).

Rambutan (Nephelium lappaceum L.) is a tropical fruit from Asia which has become the main target of many studies involving polyphenolic analysis. Mexico produces over 8 million tons per year of rambutan, generating a huge amount of agro-industrial waste since only the pulp is used and the peel, which comprises around 45% of the fruit's weight, is left behind. This waste can later be used in the recovery of polyphenolic fractions. In this work, emerging technologies such as microwave, ultrasound, and the hybridization of both were tested in the extraction of phenolic compounds from Mexican rambutan peel. The results show that the hybrid technology extraction yielded the highest polyphenolic content (176.38 mg GAE/g of dry rambutan peel). The HPLC/MS/ESI analysis revealed three majoritarian compounds: geraniin, corilagin, and ellagic acid. These compounds explain the excellent results for the biological assays, namely antioxidant activity evaluated by the DPPH, ABTS, and LOI (Lipid oxidation inhibition) assays that exhibited great antioxidant capacity with IC50 values of 0.098, 0.335, and 0.034 mg/mL respectively, as well as prebiotic activity demonstrated by a µMax (maximum growth) of 0.203 for Lactobacillus paracasei. Lastly, these compounds have shown no hemolytic activity, opening the door for the elaboration of different products in the food, cosmetic, and pharmaceutical industries.

Temperature effect on oxidative stress and egg quality-related genes on post-ovulatory eggs and ovary of red cusk-eel (Genypterus chilensis).

Red cusk-eel (Genypterus chilensis) is a native species with potential for Chilean aquaculture diversification. However, no information exists on the effects of temperature on oxidative stress and eggs quality markers in post-ovulatory eggs and ovary of this species. We determine that high and low temperature generate oxidative damage on post-ovulatory eggs, with no effect on ovary. Temperature induces thermal stress markers expression on post-ovulatory eggs, and modulates antioxidant and eggs quality markers on post-ovulatory eggs and ovary, information to consider for quality evaluation in the red cusk-eel management.

Early Optimization Stages of Agave lechuguilla Bagasse Processing toward Biorefinement: Drying Procedure and Enzymatic Hydrolysis for Flavonoid Extraction.

Agave lechuguilla agro-waste is a promising renewable material for biorefining purposes. The procurement of added-value co-products, such as bioactive phytochemicals, is required to improve bioprocesses and promote the bio-based economy of the productive areas of Mexico. In this study, we aimed to evaluate the effect of post-harvest management and enzymatic pretreatment as the first stages of the A. lechuguilla valorization process. Four drying methods were compared, and enzymatic hydrolysis was optimized to obtain a flavonoid-enriched extract applying ultrasound-assisted extraction. In both experiments, the total phenolic (TPC) and flavonoid (TFC) contents, HPLC-UV flavonoid profiles, and radical scavenging capacity (DPPH) were considered as response variables. The results demonstrated that light exposure during the drying process particularly affected the flavonoid content, whereas oven-dehydration at 40 °C in the dark preserved the flavonoid diversity and antioxidant functionality of the extracts. Flavonoid glycoside recovery, particularly anthocyanidins, was 1.5-1.4-fold enhanced by enzymatic hydrolysis using the commercial mix Ultraflo© under optimized conditions (pH 4, 40 °C, 180 rpm, and 2.5 h) compared to the unpretreated biomass. The extraction of flavonoids from A. lechuguilla bagasse can be carried out using a scalable drying method and enzymatic pretreatment. This study confirmed the potential of this agro-waste as a source of marketable natural products.

Effects of crowding on the three main proteolytic mechanisms of skeletal muscle in rainbow trout (Oncorhynchus mykiss).

BACKGROUND: Skeletal muscle is one of the tissues most affected by stress conditions. The protein degradation in this tissue is vital for the supply of energy mediated by different proteolytic pathways such as the ubiquitin-proteasome (UPS), autophagy-lysosome (ALS) and the calpain/calpastatin system (CCS). Nevertheless, the regulation of this proteolytic axis under stress conditions is not yet completely clear. Chile is the main producer of rainbow trout (Oncorhynchus mykiss) in the world. This intensive fish farming has resulted in growing problems as crowding and stress are one of the major problems in the freshwater stage. In this context, we evaluated the crowding effect in juvenile rainbow trout kept in high stocking density (30 kg/m3) for 15, 45 and 60 days, using a control group of fish (10 kg/m3). RESULTS: Plasmatic cortisol and glucose were evaluated by enzyme immunoassay. The mRNA levels of stress-related genes (gr1, gr2, mr, hsp70, klf15 and redd1), markers of the UPS (atrogin1 and murf1) and CCS (capn1, capn1, cast-l and cast-s) were evaluated using qPCR. ALS (LC3-I/II and P62/SQSTM1) and growth markers (4E-BP1 and ERK) were measured by Western blot analysis. The cortisol levels increased concomitantly with weight loss at 45 days of crowding. The UPS alone was upregulated at 15 days of high stocking density, while ALS activation was observed at 60 days. However, the CCS was inactivated during the entire trial. CONCLUSION: All these data suggest that stress conditions, such as crowding, promote muscle degradation in a time-dependent manner through the upregulation of the UPS at early stages of chronic stress and activation of the ALS in long-term stress, while the CCS is strongly inhibited by stress conditions in the rainbow trout muscle farmed during freshwater stage. Our descriptive study will allow perform functional analysis to determine, in a more detailed way, the effect of stress on skeletal muscle physiology as well as in the animal welfare in rainbow trout. Moreover, it is the first step to elucidate the optimal crop density in the freshwater stage and improve the standards of Chilean aquaculture.

Zebrafish (Danio rerio) as an animal model for bath infection by Flavobacterium psychrophilum.

Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout syndrome in freshwater salmonid fish worldwide, generating injuries and high mortality rates. Despite several studies on this bacterium, the infection mechanism remains unknown due to limitations in the employed animal models. In this work, we propose using zebrafish (Danio rerio) as a model for studying bacterial pathogenicity. To substantiate this proposal, zebrafish infection by F. psychrophilum strain JIP 02/86 was characterized. Zebrafish larvae were infected using the bath method, and morphological changes and innate immune system activation were monitored using transgenic fish. Salmonid-like infection phenotypes were observed in 4.74% of treated larvae, as manifested by fin, muscle and caudal peduncle damage. Symptomatic and dead larvae accounted for 1.35% of all challenged larvae. Interestingly, infected larvae with no infection phenotypes showed stronger innate immune system activation than specimens with phenotypes. A failure of function assay for myeloid factor pu.1 resulted in more infected larvae (up to 43.5%), suggesting that low infection rates by F. psychrophilum would be due to the protective actions of the innate immune system against this bacterium in zebrafish larvae. Our results support the use of zebrafish as an infection model for studying F. psychrophilum. Furthermore, the percentage of infected fish can be modulated by disturbing, to varying extents, the differentiation of myeloid cells. Using this evidence as a starting point, different aspects of the infection mechanism of F. psychrophilum could be studied in vivo.

Improved reductive transformation of iopromide by magnetite containing reduced graphene oxide nanosacks as electron shuttles.

The novel application of magnetite containing reduced graphene oxide nanosacks (MrGO-N) as electron shuttles to improve the reductive degradation of pharmaceutical pollutant, iopromide (IOP), was evaluated. The MrGO-N were synthesized by ultrasonicated nebulization process, and their physicochemical characterization was performed by potentiometric titrations, zeta potential, high resolution transmission electron microscopy (HR-TEM), X-ray diffraction, as well as by Raman and Fourier transform infrared spectroscopies. Results demonstrated the thermal reduction of precursor graphene oxide sheets, the removal of different oxygenated groups, and the successful assembly of magnetite nanoparticles (MNP) in the graphene sacks. Also, reduction experiments revealed 72 % of IOP removal efficiency and up to 2.5-fold faster degradation of this pollutant performed with MrGO-N as redox catalysts in batch assays and with sulfide as electron donor. Chemical transformation pathway of IOP provides evidence of complete dehalogenation and further transformation of aromatic ring substituents. Greater redox-mediating ability of MrGO-N was observed, which was reflected in the catalytic activity of these nanomaterials during the reductive degradation of IOP. Transformation byproducts with simpler chemical structure were identified, which could lead to complete degradation by conventional methodologies in a complementary treatment process. Redox-mediating activity of MrGO-N could potentially be applied in wastewater treatment systems in order to facilitate the biodegradation of priority contaminants.

Ellagic Acid Recovery by Solid State Fermentation of Pomegranate Wastes by Aspergillus niger and Saccharomyces cerevisiae: A Comparison.

Fermentation in solid state culture (SSC) has been the focus of increasing interest because of its potential for industrial applications. In previous studies SSC of pomegranate wastes by Aspergillus niger has been extensively developed and optimized for the recovery of ellagic acid (EA), a high value bioactive. In this study we comparatively investigated the SSC of powdered pomegranate husks by A. niger and Saccharomyces cerevisiae and evaluated the recovery yields of EA by an ultrasound and microwave-assisted 7:3 water/ethanol extraction. Surprisingly enough, the yields obtained by S. cerevisiae fermentation (4% w/w) were found 5-fold higher than those of the A. niger fermented material, with a 10-fold increase with respect to the unfermented material. The EA origin was traced by HPLC analysis that showed a significant decrease in the levels of punicalagin isomers and granatin B and formation of punicalin following fermentation. Other extraction conditions that could warrant a complete solubilization of EA were evaluated. Using a 1:100 solid to solvent ratio and DMSO as the solvent, EA was obtained in 4% yields from S. cerevisiae fermented husks at a high purity degree. Hydrolytic treatment of S. cerevisiae fermented pomegranate husks afforded a material freed of the polysaccharides components that gave recovery yields of EA up to 12% w/w.

Novel application of magnetic nano-carbon composite as redox mediator in the reductive biodegradation of iopromide in anaerobic continuous systems.

The redox-mediating capacity of magnetic reduced graphene oxide nanosacks (MNS) to promote the reductive biodegradation of the halogenated pollutant, iopromide (IOP), was tested. Experiments were performed using glucose as electron donor in an upflow anaerobic sludge blanket (UASB) reactor under methanogenic conditions. Higher removal efficiency of IOP in the UASB reactor supplied with MNS as redox mediator was observed as compared with the control reactor lacking MNS. Results showed 82% of IOP removal efficiency under steady state conditions in the UASB reactor enriched with MNS, while the reactor control showed IOP removal efficiency of 51%. The precise microbial transformation pathway of IOP was elucidated by high-performance liquid chromatography coupled to mass spectroscopy (HPLC-MS) analysis. Biotransformation by-products with lower molecular weight than IOP molecule were identified in the reactor supplied with MNS, which were not detected in the reactor control, indicating the contribution of these magnetic nano-carbon composites in the redox conversion of this halogenated pollutant. Reductive reactions of IOP favored by MNS led to complete dehalogenation of the benzene ring and partial rupture of side chains of this pollutant, which is the first step towards its complete biodegradation. Possible reductive mechanisms that took place in the biodegradation of IOP were stated. Finally, the novel and successful application of magnetic graphene composites in a continuous bioreactor to enhance the microbial transformation of IOP was demonstrated.

Cortisol Induces Reactive Oxygen Species Through a Membrane Glucocorticoid Receptor in Rainbow Trout Myotubes.

Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predominantly affects target tissues through the genomic pathway, which involves interacting with cytoplasmic glucocorticoid receptors, and thereby, modulating stress-response gene expressions. Cortisol also produces rapid effects via non-genomic pathways, which do not involve gene transcription. Although cortisol-mediated genomic pathways are well documented in teleosts, non-genomic pathways are not fully understood. Moreover, no studies have focused on the contribution of non-genomic cortisol pathways in compensatory stress responses in fish. In this study, rainbow trout (Oncorhynchus mykiss) skeletal myotubes were stimulated with physiological concentrations of cortisol and cortisol-BSA, a membrane-impermeable agent, resulting in an early induction of reactive oxygen species (ROS). This production was not suppressed by transcription or translation inhibitors, suggesting non-genomic pathway involvement. Moreover, myotube preincubation with RU486 and NAC completely suppressed cortisol- and cortisol-BSA-induced ROS production. Subcellular fractionation analysis revealed the presence of cell membrane glucocorticoid receptors. Finally, cortisol-BSA induced a significant increase in ERK1/2 and CREB phosphorylation, as well as in CREB-dependent transcriptional activation of the pgc1a gene expression. The obtained results strongly suggest that cortisol acts through a non-genomic glucocorticoid receptor-mediated pathway to induce ROS production and contribute to ERK/CREB/PGC1-α signaling pathway activation as stress compensation mechanisms. J. Cell. Biochem. 118: 718-725, 2017. © 2016 Wiley Periodicals, Inc.

Immobilization of biogenic Pd(0) in anaerobic granular sludge for the biotransformation of recalcitrant halogenated pollutants in UASB reactors.

The capacity of anaerobic granular sludge to reduce Pd(II), using ethanol as electron donor, in an upflow anaerobic sludge blanket (UASB) reactor was demonstrated. Results confirmed complete reduction of Pd(II) and immobilization as Pd(0) in the granular sludge. The Pd-enriched sludge was further evaluated regarding biotransformation of two recalcitrant halogenated pollutants: 3-chloro-nitrobenzene (3-CNB) and iopromide (IOP) in batch and continuous operation in UASB reactors. The superior removal capacity of the Pd-enriched biomass when compared with the control (not exposed to Pd) was demonstrated in both cases. Results revealed 80 % of IOP removal efficiency after 100 h of incubation in batch experiments performed with Pd-enriched biomass whereas only 28 % of removal efficiency was achieved in incubations with biomass lacking Pd. The UASB reactor operated with the Pd-enriched biomass achieved 81 ± 9.5 % removal efficiency of IOP and only 61 ± 8.3 % occurred in the control reactor lacking Pd. Regarding 3-CNB, it was demonstrated that biogenic Pd(0) promoted both nitro-reduction and dehalogenation resulting in the complete conversion of 3-CNB to aniline while in the control experiment only nitro-reduction was documented. The complete biotransformation pathway of both contaminants was proposed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis evidencing a higher degree of nitro-reduction and dehalogenation of both contaminants in the experiments with Pd-enriched anaerobic sludge as compared with the control. A biotechnological process is proposed to recover Pd(II) from industrial streams and to immobilize it in anaerobic granular sludge. The Pd-enriched biomass is also proposed as a biocatalyst to achieve the biotransformation of recalcitrant compounds in UASB reactors.

The complete biodegradation pathway of ellagitannins by Aspergillus niger in solid-state fermentation.

Our research group has found preliminary evidences of the fungal biodegradation pathway of ellagitannins, revealing first the existence of an enzyme responsible for ellagitannins degradation, which hydrolyzes pomegranate ellagitannins and it was called ellagitannase or elagitannin acyl hydrolase. However, it is necessary to generate new and clear information in order to understand the ellagitannin degradation mechanisms. This work describes the distinctive and unique features of ellagitannin metabolism in fungi. In this study, hydrolysis of pomegranate ellagitannins by Aspergillus niger GH1 was studied by solid-state culture using polyurethane foam as support and pomegranate ellagitannins as substrate. The experiment was performed during 36 h. Results showed that ellagitannin biodegradation started after 6 h of fermentation, reaching the maximal biodegradation value at 18 h. It was observed that ellagitannase activity appeared after 6 h of culture, then, the enzymatic activity was maintained up to 24 h of culture reaching 390.15 U/L, after this period the enzymatic activity decreased. Electrophoretic band for ellagitannase was observed at 18 h. A band obtained using non-denaturing electrophoresis was identified as ellagitannase, then, a tandem analysis to reveal the ellagitannase activity was performed using Petri plate with pomegranate ellagitannins. The extracts were analyzed by HPLC/MS to evaluate ellagitannins degradation. Punicalin, gallagic acid, and ellagic acid were obtained from punicalagin. HPLC/MS analysis identified the gallagic acid as an intermediate molecule and immediate precursor of ellagic acid. The potential application of catabolic metabolism of ellagitannin hydrolysis for ellagic acid production is outlined.

mRNA-seq reveals skeletal muscle atrophy in response to handling stress in a marine teleost, the red cusk-eel (Genypterus chilensis).

BACKGROUND: Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chilean aquaculture industry. However, there is no information on the stress- and cortisol-induced mechanisms that decrease skeletal muscle growth in this teleost. RESULTS: Using Illumina RNA-seq technology, skeletal muscle sequence reads for G. chilensis were generated under control and handling stress conditions. Reads were mapped onto a reference transcriptome, resulting in the in silico identification of 785 up-regulated and 167 down-regulated transcripts. Gene ontology enrichment analysis revealed a significant up-regulation of catabolic genes associated with skeletal muscle atrophy. These results were validated by RT-qPCR analysis for ten candidates genes involved in ubiquitin-mediated proteolysis, autophagy and skeletal muscle growth. Additionally, using a primary culture of fish skeletal muscle cells, the effect of cortisol was evaluated in relation to red cusk-eel skeletal muscle atrophy. CONCLUSIONS: The present data demonstrated that handling stress promotes skeletal muscle atrophy in the marine teleost G. chilensis through the expression of components of the ubiquitin-proteasome and autophagy-lysosome systems. Furthermore, cortisol was a powerful inductor of skeletal muscle atrophy in fish myotubes. This study is an important step towards understanding the atrophy system in non-model teleost species and provides novel insights on the cellular and molecular mechanisms that control skeletal muscle growth in early vertebrates.

Fungal biodegradation of pomegranate ellagitannins.

Ellagitannins (ETs) are phytochemicals derived from secondary metabolism associated to defense system, with complex chemical structures, which have high participation during all stages of protection against microbial infection. In this study, we report the fungal biodegradation of a bioactive ET, named punicaline which was recovered and purified from pomegranate peels and used as carbon source in solid-state culture (SSC) using polyurethane as solid support. SSC was kinetically monitored during 36 h of incubation time. ETs and glycosides consumption were spectrophotometrically determined. Ellagic acid (EA) accumulation was analyzed by HPLC. Several enzymatic activities were assayed (cellulase, xylanase, ß-glucosydase, polyphenoloxidase, tannase, and ET hydrolyzing activities). The consumption levels of ETs and glycosides were 66 and 40%, while EA accumulation reached 42.02 mg g(-1). A differential pattern of enzymatic activities was found; evidence from our studies suggests that the ET hydrolyzing activity is directly associated to EA accumulation, and production of this enzyme may represent the most critical step to successfully develop a bioprocess for production of an important bioactive compound, the EA.

Recent Advances in the Extraction and Characterization of Bioactive Compounds from Corn By-Products.

Maize comes in a variety of colors, including white, yellow, red, blue, and purple, which is due to the presence of phytochemicals such as carotenoids, anthocyanins, flavonoids, phytosterols, and some hydroxycinnamic acid derivatives. In Mexico, maize is primarily grown for human consumption; however, maize residues comprise 51-58% of the total maize plant weight (stalks, leaves, ears, and husks) and are mainly used as livestock feed. These residues contain numerous bioactive compounds that interest the industry for their potential health benefits in preventing or treating degenerative diseases. This review explores the current knowledge and highlights key aspects related to the extraction methods and different techniques for identifying the bioactive compounds found in maize by-products.

IGF-1 induces IP3 -dependent calcium signal involved in the regulation of myostatin gene expression mediated by NFAT during myoblast differentiation.

Skeletal muscle differentiation is a complex and highly regulated process characterized by cell cycle arrest, which is associated with morphological changes including myoblast alignment, elongation, and fusion into multinucleated myotubes. This is a balanced process dynamically coordinated by positive and negative signals such as the insulin-like growth factor I (IGF-1) and myostatin (MSTN), respectively. In this study, we report that the stimulation of skeletal myoblasts during differentiation with IGF-1 induces a rapid and transient calcium increase from intracellular stores, which are principally mediated through the phospholipase C gamma (PLC γ)/inositol 1,4,5-triphosphate (IP3 )-dependent signaling pathways. This response was completely blocked when myoblasts were incubated with LY294002 or transfected with the dominant-negative p110 gamma, suggesting a fundamental role of phosphatidylinositol 3-kinase (PI3K) in PLCγ activation. Additionally, we show that calcium released via IP3 and induced by IGF-1 stimulates NFAT-dependent gene transcription and nuclear translocation of the GFP-labeled NFATc3 isoform. This activation was independent of extracellular calcium influx and calcium release mediated by ryanodine receptor (RyR). Finally, we examined mstn mRNA levels and mstn promoter activity in myoblasts stimulated with IGF-1. We found a significant increase in mRNA contents and in reporter activity, which was inhibited by cyclosporin A, 11R-VIVIT, and by inhibitors of the PI3Kγ, PLCγ, and IP3 receptor. Our results strongly suggest that IGF-1 regulates myostatin transcription through the activation of the NFAT transcription factor in an IP3 /calcium-dependent manner. This is the first study to demonstrate a role of calcium-dependent signaling pathways in the mRNA expression of myostatin.

Revealing coastal upwelling impact on the muscle growth of an intertidal fish.

Upwelling oceanographic phenomenon is associated with increased food availability, low seawater temperature and pH. These conditions could significantly affect food quality and, in consequence, the growth of marine species. One of the most important organismal traits is somatic growth, which is highly related to skeletal muscle. In fish, skeletal muscle growth is highly influenced by environmental factors (i.e. temperature and nutrient availability) that showed differences between upwelling and downwelling zones. Nevertheless, there are no available field studies regarding the impact of those conditions on fish muscle physiology. This work aimed to evaluate the muscle fibers size, protein content, gene expression of growth and atrophy-related genes in fish sampled from upwelling and downwelling zones. Seawater and fish food items (seaweeds) samples were collected from upwelling and downwelling zones to determine the habitat's physical-chemical variations and the abundance of biomolecules in seaweed tissue. In addition, white skeletal muscle samples were collected from an intertidal fish to analyze muscular histology, the growth pathways of protein kinase B and the extracellular signal-regulated kinase; and the gene expression of growth- (insulin-like growth factor 1 and myosin heavy-chain) and atrophy-related genes (F-box only protein 32 and muscle RING-finger protein-1). Upwelling zones revealed higher nutrients in seawater and higher protein content in seaweed than samples from downwelling zones. Moreover, fish from upwelling zones presented a greater size of muscle fibers and protein content compared to downwelling fish, associated with lower protein ubiquitination and gene expression of F-box only protein 32. Our data indicate an attenuated use of proteins as energy source in upwelling conditions favoring protein synthesis and muscle growth. This report shed lights of how oceanographic conditions may modulate food quality and fish muscle physiology in an integrated way, with high implications for marine conservation and sustainable fisheries management.

Bioactive protein hydrolysates obtained from amaranth by fermentation with lactic acid bacteria and Bacillus species.

Protein hydrolysates are a promising source of bioactive peptides. One strategy by which they can be obtained is fermentation. This method uses the proteolytic system of microorganisms to hydrolyze the parental protein. Fermentation is a little-explored method for obtaining protein hydrolysates from amaranth. Different strains of lactic acid bacteria (LAB) and Bacillus species isolated from goat milk, broccoli, aguamiel, and amaranth flour were used in this work. First, the total protein degradation (%TPD) of amaranth demonstrated by the strains was determined. The results ranged from 0 to 95.95%, the strains that produced a higher %TPD were selected. These strains were identified by molecular biology and were found to correspond to the genera Enterococcus, Lactobacillus, Bacillus, and Leuconostoc. Fermentation was carried out with amaranth flour and the selected strains. After this process, water/salt extracts (WSE) containing the released protein hydrolysates were obtained from amaranth doughs. The peptide concentration was measured by the OPA method. The antioxidant, antihypertensive and antimicrobial activity of the WSE was evaluated. In the FRAP test, the best WSE was LR9 with a concentration of 1.99 µMTE/L ± 0.07. In ABTS, 18C6 obtained the highest concentration with 19.18 µMTE/L ± 0.96. In the DPPH test, there was no significant difference. In terms of antihypertensive activity, inhibition percentages ranging from 0 to 80.65% were obtained. Some WSE were found to have antimicrobial properties against Salmonella enterica and Listeria monocytogenes. Fermentation of amaranth with LAB and Bacillus spp. allowed the release of protein hydrolysates with antioxidant, antihypertensive, and antimicrobial activity.