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Ram sperm undergo a sequence of physiological and biochemical changes collectively termed as capacitation to perform oocyte fertilization. However, the protein changes induced by capacitation remain in need of further exploration. Thus, the present study investigated the comparative proteomic profiling in ram spermatozoa under non-capacitating (NC) and capacitating (CAP) conditions in vitro using a liquid chromatography-tandem mass spectrometry combined with tandem mass tag labeling strategy. As a results, 2050 proteins were identified and quantified; 348 of them were differentially abundant, with 280 of the proteins upregulated and 68 of the proteins downregulated between the CAP and NC spermatozoa, respectively. Functional enrichment analysis indicated that the differentially abundant proteins Prune Exopolyphosphatase 1, Galactose-1-Phosphate Uridylyltransferase, and ATP Citrate Lyase were strictly related to energy production and conversion, and Phosphoglycolate phosphatase, Glucosamine-6-Phosphate Deaminase 1 and 2 were related to metabolism, RNA processing, and vesicular transport pathways. Furthermore, the networks of protein-protein interaction indicated a strong interaction among these differential proteins in annotated pathways such as ubiquitin and transport metabolism. Our findings indicate that capacitation progress might be regulated through different pathways, providing insights into mechanisms involved in ram sperm capacitation and fertility.
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Elongation of very long-chain fatty acids protein 6 (ELOVL6) plays a pivotal role in the synthesis of endogenous fatty acids, influencing energy balance and metabolic diseases. The primary objective of this study was to discover the molecular attributes and regulatory roles of ELOVL6 in male Nile tilapia, Oreochromis niloticus. The full-length cDNA of elovl6 was cloned from male Nile tilapia, and was determined to be 2255-bp long, including a 5'-untranslated region of 193 bp, a 3'-untranslated region of 1252 bp, and an open reading frame of 810 bp encoding 269 amino acids. The putative protein had typical features of ELOVL proteins. The transcript levels of elovl6 differed among various tissues and among fish fed with different dietary lipid sources. Knockdown of elovl6 in Nile tilapia using antisense RNA technology resulted in significant alterations in hepatic morphology, long-chain fatty acid synthesis, and fatty acid oxidation, and led to increased fat deposition in the liver and disrupted glucose/lipid metabolism. A comparative transcriptomic analysis (elovl6 knockdown vs. the negative control) identified 5877 differentially expressed genes with significant involvement in key signaling pathways including the peroxisome proliferator-activated receptor signaling pathway, fatty acid degradation, glycolysis/gluconeogenesis, and the insulin signaling pathway, all of which are crucial for lipid and glucose metabolism. qRT-PCR analyses verified the transcript levels of 13 differentially expressed genes within these pathways. Our findings indicate that elovl6 knockdown in male tilapia impedes oleic acid synthesis, culminating in aberrant nutrient metabolism.
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Ciclídeos , Elongases de Ácidos Graxos , Animais , Masculino , Elongases de Ácidos Graxos/genética , Elongases de Ácidos Graxos/metabolismo , Ciclídeos/genética , Ciclídeos/metabolismo , Metabolismo dos Lipídeos/genética , Inativação Gênica , Fígado/metabolismo , Nutrientes/metabolismo , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica , Sequência de Aminoácidos , Clonagem Molecular , Acetiltransferases/genética , Acetiltransferases/metabolismo , Técnicas de Silenciamento de GenesRESUMO
Temperature is one of the most important non-genetic sex differentiation factors for fish. The technique of high temperature-induced sex reversal is commonly used in Nile tilapia (Oreochromis niloticus) culture, although the molecular regulatory mechanisms involved in this process remain unclear. The brain is an essential organ for the regulation of neural signals involved in germ cell differentiation and gonad development. To investigate the regulatory roles of miRNAs-mRNAs in the conversion of female to male Nile tilapia gender under high-temperature stress, we compared RNA-Seq data from brain tissues between a control group (28 °C) and a high temperature-treated group (36 °C). The result showed that a total of 123,432,984 miRNA valid reads, 288,202,524 mRNA clean reads, 1128 miRNAs, and 32,918 mRNAs were obtained. Among them, there were 222 significant differentially expressed miRNAs (DE miRNAs) and 810 differentially expressed mRNAs (DE mRNAs) between the two groups. Eight DE miRNAs and eight DE mRNAs were randomly selected, and their expression patterns were validated by qRT-PCR. The miRNA-mRNA co-expression network demonstrated that 40 DE miRNAs targeted 136 protein-coding genes. Functional enrichment analysis demonstrated that these genes were involved in several gonadal differentiation pathways, including the oocyte meiosis signaling pathway, progesterone-mediated oocyte maturation signaling pathway, cell cycle signaling pathway and GnRH signaling pathway. Then, an interaction network was constructed for 8 miRNAs (mir-137-5p, let-7d, mir-1388-5p, mir-124-4-5p, mir-1306, mir-99, mir-130b and mir-21) and 10 mRNAs (smc1al, itpr2, mapk1, ints8, cpeb1b, bub1, fbxo5, mmp14b, cdk1 and hrasb) involved in the oocyte meiosis signaling pathway. These findings provide novel information about the mechanisms underlying miRNA-mediated sex reversal in female Nile tilapia.
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Encéfalo , Ciclídeos , MicroRNAs , RNA Mensageiro , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , Ciclídeos/genética , Ciclídeos/metabolismo , Ciclídeos/crescimento & desenvolvimento , Feminino , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Encéfalo/metabolismo , Encéfalo/crescimento & desenvolvimento , Diferenciação Sexual , Masculino , Temperatura Alta , Redes Reguladoras de Genes , Processos de Determinação SexualRESUMO
Magnetic impurities in superconductors are of increasing interest due to emergent Yu-Shiba-Rusinov (YSR) states and Majorana zero modes for fault-tolerant quantum computation. However, a direct relationship between the YSR multiple states and magnetic anisotropy splitting of quantum impurity spins remains poorly characterized. By using scanning tunneling microscopy, we systematically resolve individual transition-metal (Fe, Cr, and Ni) impurities induced YSR multiplets as well as their Zeeman effects in the K3C60 superconductor. The YSR multiplets show identical d orbital-like wave functions that are symmetry-mismatched to the threefold K3C60(1 1 1) host surface, breaking point-group symmetries of the spatial distribution of YSR bound states in real space. Remarkably, we identify an unprecedented fermion-parity-preserving quantum phase transition between ground states with opposite signs of the uniaxial magnetic anisotropy that can be manipulated by an external magnetic field. These findings can be readily understood in terms of anisotropy splitting of quantum impurity spins, and thus elucidate the intricate interplay between the magnetic anisotropy and YSR multiplets.
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Seasonal environmental shifts and improper eating habits are the important causes of diarrhea in children and growing animals. Whether adjusting feeding time at varying temperatures can modify cecal bacterial structure and improve diarrhea remains unknown. Three batches growing rabbits with two groups per batch were raised under different feeding regimens (fed at daytime vs. nighttime) in spring, summer and winter separately, and contents were collected at six time points in 1 day and used 16S rRNA sequencing to investigate the effects of feeding regimens and season on the composition and circadian rhythms of cecum bacteria. Randomized forest regression screened 12 genera that were significantly associated with seasonal ambient temperature changes. Nighttime feeding reduced the abundance of the conditionally pathogenic bacteria Desulfovibrio and Alistipes in summer and Campylobacter in winter. And also increases the circadian rhythmic Amplicon Sequence Variants in the cecum, enhancing the rhythm of bacterial metabolic activity. This rhythmic metabolic profile of cecum bacteria may be conducive to the digestion and absorption of nutrients in the host cecum. In addition, this study has identified 9 genera that were affected by the combination of seasons and feeding time. In general, we found that seasons and feeding time and their combinations affect cecum composition and circadian rhythms, and that daytime feeding during summer and winter disrupts the balance of cecum bacteria of growing rabbits, which may adversely affect cecum health and induce diarrhea risk.
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The Chinese caterpillar mushroom, Ophiocordyceps sinensis (O. sinensis), is a rarely medicinal fungus in traditional chinese herbal medicine due to its unique medicinal values, and the expression stability of reference genes is essential to normalize its gene expression analysis. In this study, BestKeeper, NormFinder and geNorm, three authoritative statistical arithmetics, were applied to evaluate the expression stability of sixteen candidate reference genes (CRGs) in O. sinensis under different stress [low temperature (4°C), light treatment (300 lx), NaCl (3.8%)] and different development stages (mycelia, primordia and fruit bodies) and formation of morphologic mycelium (aeriasubstrate, hyphae knot mycelium). The paired variation values indicated that two genes could be enough to accurate standardization exposed to different conditions of O.sinensis. Among these sixteen CRGs, 18S ribosomal RNA (18S rRNA) and beta-Tubulin (ß-TUB) showed the topmost expression stability in O.sinensis exposed to all conditions, while glutathione hydrolase proenzym (GGT) and Phosphoglucose isomerase (PGI) showed the least expression stability. The optimal reference gene in different conditions was various. ß-TUB and Ubiquitin (UBQ) were identified as the two most stable genes in different primordia developmental stage, while phosphoglucomutase (PGM) with elongation factor 1-alpha (EF1-α) and 18S rRNA with UBQ were the most stably expressed for differentially morphologic mycelium stages and different stresses, respectively. These results will contribute to more accurate evaluation of the gene relative expression levels in O.sinensis under different conditions using the optimal reference gene in real-time quantitative PCR (RT-qPCR) analysis.
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Cordyceps , Cordyceps/genética , RNA Ribossômico 18S/genética , Perfilação da Expressão Gênica/métodos , Genes de Plantas , Reação em Cadeia da Polimerase em Tempo Real/métodos , Padrões de Referência , Tubulina (Proteína)/genética , Ubiquitina/genéticaRESUMO
Oogenesis is a complex process regulated by precise coordination of multiple factors, including maternal genes. Zygote arrest 1 (zar1) has been identified as an ovary-specific maternal gene that is vital for oocyte-to-embryo transition and oogenesis in mouse and zebrafish. However, its function in other species remains to be elucidated. In the present study, zar1 was identified with conserved C-terminal zinc finger domains in Nile tilapia. zar1 was highly expressed in the ovary and specifically expressed in phase I and II oocytes. Disruption of zar1 led to the failed transition from oogonia to phase I oocytes, with somatic cell apoptosis. Down-regulation and failed polyadenylation of figla, gdf9, bmp15 and wee2 mRNAs were observed in the ovaries of zar1-/- fish. Cpeb1, a gene essential for polyadenylation that interacts with Zar1, was down-regulated in zar1-/- fish. Moreover, decreased levels of serum estrogen and increased levels of androgen were observed in zar1-/- fish. Taken together, zar1 seems to be essential for tilapia oogenesis by regulating polyadenylation and estrogen synthesis. Our study shows that Zar1 has different molecular functions during gonadal development by the similar signaling pathway in different species.
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Proteínas do Ovo , Proteínas de Peixes , Tilápia , Animais , Feminino , Camundongos , Ciclídeos/genética , Ciclídeos/metabolismo , Proteínas do Ovo/metabolismo , Estrogênios , Fatores de Poliadenilação e Clivagem de mRNA/genética , Oogênese/genética , Poliadenilação , Tilápia/genética , Tilápia/metabolismo , Fatores de Transcrição/genética , Peixe-Zebra/metabolismo , Proteínas de Peixes/metabolismoRESUMO
The blood-brain barrier (BBB) is mainly composed of specialized endothelial cells, which can resist harmful substances, transport nutrients, and maintain the stability of the brain environment. In this study, an endothelial cell line from tilapia (Oreochromis niloticus) named TVEC-01 was successfully established. During the earlier establishment phase of the cell line, the TVEC-01 cells were persistently exposed to an astrocyte-conditioned medium (ACM). TVEC-01 cells were identified as an endothelial cell line. TVEC-01 cells retained the multiple functions of endothelial cells and were capable of performing various experiments in vitro. Furthermore, TVEC-01 cells efficiently expressed BBB-related tight junctions and key efflux transporters. From the results of the qRT-PCR, we found that the TVEC-01 cell line did not gradually lose BBB characteristics after persistent and repetitive passages, which was different from the vast majority of immortalized endothelial cells. The results showed that ACM induced up-regulation of the expression levels of multiple BBB-related genes in TVEC-01 cells. We confirmed that Streptococcus agalactiae was capable of invading the TVEC-01 cells and initiating a series of immune responses, which provided a theoretical basis for S. agalactiae to break through the BBB of teleost through the transcellular traversal pathway. In summary, we have successfully constructed an endothelial cell line of teleost, named TVEC-01, which can be used in many experiments in vitro and even for constructing BBB in vitro. Moreover, it was confirmed that S. agalactiae broke through the BBB of teleost through the transcellular traversal pathway and caused meningitis.
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Astrócitos , Barreira Hematoencefálica , Animais , Barreira Hematoencefálica/metabolismo , Astrócitos/fisiologia , Meios de Cultivo Condicionados/farmacologia , Meios de Cultivo Condicionados/metabolismo , Células Endoteliais/metabolismo , Encéfalo/metabolismoRESUMO
Tilapia tolerate hypoxia; thus, they are an excellent model for the study of hypoxic adaptation. In this study, we determined the effect of acute hypoxia stress on the antioxidant capacity, metabolism, and gill/liver ultrastructure of male genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Fish were kept under control (dissolved oxygen (DO): 6.5 mg/L) or hypoxic (DO: 1.0 mg/L) conditions for 72 h. After 2 h of hypoxia stress, antioxidant enzyme activities in the heart and gills decreased, while the malondialdehyde (MDA) content increased. In contrast, in the liver, antioxidant enzyme activities increased, and the MDA content decreased. From 4 to 24 h of hypoxia stress, the antioxidant enzyme activity increased in the heart but not in the liver and gills. Cytochrome oxidase activity was increased in the heart after 4 to 8 h of hypoxia stress, while that in the gills decreased during the later stages of hypoxia stress. Hypoxia stress resulted in increased Na+-K+-ATP activity in the heart, as well as hepatic vacuolization and gill lamella elongation. Under hypoxic conditions, male GIFT exhibit dynamic and complementary regulation of antioxidant systems and metabolism in the liver, gills, and heart, with coordinated responses to mitigate hypoxia-induced damage.
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Purpose Numerous techniques based on deep learning have been utilized in sparse view computed tomography (CT) imaging. Nevertheless, the majority of techniques are instinctively constructed utilizing state-of-the-art opaque convolutional neural networks (CNNs) and lack interpretability. Moreover, CNNs tend to focus on local receptive fields and neglect nonlocal self-similarity prior information. Obtaining diagnostically valuable images from sparsely sampled projections is a challenging and ill-posed task. Method To address this issue, we propose a unique and understandable model named DCDL-GS for sparse view CT imaging. This model relies on a network comprised of convolutional dictionary learning and a nonlocal group sparse prior. To enhance the quality of image reconstruction, we utilize a neural network in conjunction with a statistical iterative reconstruction framework and perform a set number of iterations. Inspired by group sparsity priors, we adopt a novel group thresholding operation to improve the feature representation and constraint ability and obtain a theoretical interpretation. Furthermore, our DCDL-GS model incorporates filtered backprojection (FBP) reconstruction, fast sliding window nonlocal self-similarity operations, and a lightweight and interpretable convolutional dictionary learning network to enhance the applicability of the model. Results The efficiency of our proposed DCDL-GS model in preserving edges and recovering features is demonstrated by the visual results obtained on the LDCT-P and UIH datasets. Compared to the results of the most advanced techniques, the quantitative results are enhanced, with increases of 0.6-0.8 dB for the peak signal-to-noise ratio (PSNR), 0.005-0.01 for the structural similarity index measure (SSIM), and 1-1.3 for the regulated Fréchet inception distance (rFID) on the test dataset. The quantitative results also show the effectiveness of our proposed deep convolution iterative reconstruction module and nonlocal group sparse prior. Conclusion In this paper, we create a consolidated and enhanced mathematical model by integrating projection data and prior knowledge of images into a deep iterative model. The model is more practical and interpretable than existing approaches. The results from the experiment show that the proposed model performs well in comparison to the others.
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Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X , Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Redes Neurais de Computação , Razão Sinal-Ruído , Algoritmos , Imagens de FantasmasRESUMO
BACKGROUND: Largemouth bass (Micropterus salmoides) has significant economic value as a high-yielding fish species in China's freshwater aquaculture industry. Determining the major genes related to growth traits and identifying molecular markers associated with these traits serve as the foundation for breeding strategies involving gene pyramiding. In this study, we screened restriction-site associated DNA sequencing (RAD-seq) data to identify single nucleotide polymorphism (SNP) loci potentially associated with extreme growth differences between fast-growth and slow-growth groups in the F1 generation of a largemouth bass population. RESULTS: We subsequently identified associations between these loci and specific candidate genes related to four key growth traits (body weight, body length, body height, and body thickness) based on SNP genotyping. In total, 4,196,486 high-quality SNPs were distributed across 23 chromosomes. Using a population-specific genotype frequency threshold of 0.7, we identified 30 potential SNPs associated with growth traits. Among the 30 SNPs, SNP19140160, SNP9639603, SNP9639605, and SNP23355498 showed significant associations; three of them (SNP9639603, SNP9639605, and SNP23355498) were significantly associated with one trait, body length, in the F1 generation, and one (SNP19140160) was significantly linked with four traits (body weight, height, length, and thickness) in the F1 generation. The markers SNP19140160 and SNP23355498 were located near two growth candidate genes, fam174b and ppip5k1b, respectively, and these candidate genes were closely linked with growth, development, and feeding. The average body weight of the group with four dominant genotypes at these SNP loci in the F1 generation population (703.86 g) was 19.63% higher than that of the group without dominant genotypes at these loci (588.36 g). CONCLUSIONS: Thus, these four markers could be used to construct a population with dominant genotypes at loci related to fast growth. These findings demonstrate how markers can be used to identify genes related to fast growth, and will be useful for molecular marker-assisted selection in the breeding of high-quality largemouth bass.
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Bass , Polimorfismo de Nucleotídeo Único , Animais , Bass/genética , Frequência do Gene , Genótipo , Peso Corporal/genéticaRESUMO
Myostatin (encoded by mstn) negatively regulates skeletal muscle mass and affects lipid metabolism. To explore the regulatory effects of mstn on muscle development and lipid metabolism in Nile tilapia (Oreochromis niloticus), we used antisense RNA to transcriptionally knock-down mstn. At 180 days, the body weight and body length were significantly higher in the mstn-knock-down group than in the control group (p < 0.05). Additionally, fish with mstn-knock-down exhibited myofiber hyperplasia but not hypertrophy. Oil red O staining revealed a remarkable increase in the area of lipid droplets in muscle in the mstn-knockdown group (p < 0.05). Nutrient composition analyses of muscle tissue showed that the crude fat content was significantly increased in the mstn-knock-down group (p < 0.05). The contents of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids were all significantly increased in the mstn-knock-down group (p < 0.05). Comparative transcriptome analyses revealed 2420 significant differentially expressed genes between the mstn-knock-down group and the control group. KEGG analysis indicates that disruptions to fatty acid degradation, glycerolipid metabolism, and the PPAR signaling pathway affect muscle development and lipid metabolism in mstn-knock-down Nile tilapia: acaa2, eci1, and lepr were remarkably up-regulated, and acadvl, lpl, foxo3, myod1, myog, and myf5 were significantly down-regulated (p < 0.05). These results show that knock-down of mstn results in abnormal lipid metabolism, acceleration of skeletal muscle development, and increased adipogenesis and weight gain in Nile tilapia.
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Ciclídeos , Animais , Ciclídeos/genética , Ciclídeos/metabolismo , Miostatina/genética , Miostatina/metabolismo , Músculos/metabolismo , Ácidos Graxos/metabolismo , Perfilação da Expressão Gênica , Músculo Esquelético/metabolismoRESUMO
Aquaculture feed containing olive oil (OO) instead of fish oil (FO) can cause oxidative stress and impair gonad development in fish. We determined the effect of dietary OO-induced oxidative stress on ovarian development, and explored whether vitamin E (VE) could mitigate negative effects. Female Nile tilapia (Oreochromis niloticus) were fed for 10 weeks with four diets: 5% OO + 70 mg/kg VE, 5% OO + 200 mg/kg VE, 5% FO + 70 mg/kg VE, or 5% FO + 200 mg/kg VE. Dietary OO reduced the specific growth rate and gonadosomatic index, inhibited superoxide dismutase and catalase, delayed ovarian development, decreased serum sex hormone levels, and reduced ovarian triglyceride and n-3 highly unsaturated fatty acid contents. The transcript levels of genes encoding sex hormone receptors (erα, fshr, lhr) and components of the lipid metabolism pathway (pparα, pparγ, hsl, accα, elovl6), the nrf2 signaling pathway (nrf2, keap1), and the nf-κb signaling pathway (nf-κb, tnfα, infγ, il1ß) differed between the 70VE/OO and 70VE/FO groups. Supplementation with 200 mg/kg VE mitigated the adverse effects of OO by improving antioxidant capacity and alleviating inflammation and abnormal lipid metabolism. This may be because VE is an antioxidant and it can regulate the nrf2-nf-κb signaling pathway.
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The survival and growth of fish are significantly impacted by a hypoxic environment (low dissolved oxygen). In this study, we compared tissue structure, physiological changes, and mRNA/miRNA transcriptome, in gills of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) between the hypoxic group (DO: 0.55 mg/L, HG) and the control group (DO: 5 mg/L, CG). The results showed that the gill filaments in the hypoxic group showed curling, engorgement, and apoptotic cells increased, and that exposure for 96 h resulted in a reduction in the antioxidant capacity. We constructed and sequenced miRNA and mRNA libraries from gill tissues of GIFT at 96 h of hypoxia stress. Between the HG and CG, a total of 14 differentially expressed (DE) miRNAs and 1557 DE genes were obtained. GO and KEGG enrichment showed that DE genes were mainly enriched in immune and metabolic pathways such as natural killer cell mediated cytotoxicity, steroid biosynthesis, primary immunodeficiency, and synthesis and degradation of ketone bodies. Based on the results of mRNA sequencing and screening for miRNA-mRNA pairs, we selected and verified six DE miRNAs and their probable target genes. The sequencing results were consistent with the qRT-PCR validation results. The result showed that under hypoxia stress, the innate immune response was up-regulated, and the adaptive immune response was down-regulated in the gill of GIFT. The synthesis of cholesterol in gill cells is reduced, which is conducive to the absorption of solvent oxygen. These findings offer fresh information about the processes of fish adaptation to hypoxic stress.
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Ciclídeos , Doenças Metabólicas , MicroRNAs , Tilápia , Animais , Tilápia/metabolismo , Transcriptoma , Brânquias/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Hipóxia/genética , Hipóxia/veterinária , Oxigênio/metabolismo , RNA Mensageiro/metabolismoRESUMO
The asexual form of Ophiocordyceps sinensis has been controversial, but various morphologic mycelium appeared when O. sinensis was cultured under experimental conditions. To explore the generation mechanism of morphologic mycelium, developmental transcriptomes were analyzed from three kinds of mycelium (aerial mycelium, hyphae knot, and substrate mycelium). The results showed that diameter and morphology of these three kinds of mycelium were obviously different. KEGG functional enrichment analysis showed that the differential expressed genes (DEGs) of substrate mycelium were enriched in ribosomes and peroxisomes, indicating that prophase culture was rich in nutrients and the metabolism of substrate mycelium cells was vigorous in the stage of nutrient absorption. The up-DEGs of hyphae knot were mainly enriched in the oxidative phosphorylation pathway, indicating that oxidative phosphorylation was the main energy source for mycelium formation in the stage of nutrient accumulation and reproductive transformation. The up-DEGs of aerial mycelium were mainly enriched in the synthesis and degradation pathways of valine, leucine, and isoleucine, suggesting that the occurrence of aerial mycelium was related to amino acid metabolism at the later stage of culture, and nutritional stress accelerated the reproduction of asexual spores. In addition, the important roles of mycelium formation related genes were verified by combined analysis of qRT-PCR and transcriptome sequencing. Collectively, this study will provide theoretical guidance for inhibiting the occurrence of aerogenous mycelium and promoting the development of mycelium into pinhead primordia in the culture of O. sinensis in the future.
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Cordyceps , Micélio , Cordyceps/genética , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Micélio/genética , Transcriptoma/genéticaRESUMO
The enzyme 1-acylglycerol-3-phosphate O-acyltransferase 2 (AGPAT2) is an intermediate enzyme in triglyceride synthesis. The aim was to study the regulatory mechanism of AGPAT2 on Nile tilapia, Oreochromis niloticus. In this study, antisense RNA technology was used to knock-down AGPAT2 in Nile tilapia. Compared with the control groups (transfected with ultrapure water or the blank expression vector), the AGPAT2 knock-down group showed a significantly higher weight gain rate, special growth rate, visceral somatic index, and hepatopancreas somatic index; and significantly increased the total cholesterol, triglycerides, glucose, low-density lipoprotein cholesterol, and insulin levels in serum. In addition, the contents of total cholesterol and triglycerides and the abundance of superoxide dismutase, catalase, and glutathione peroxidase in the liver significantly increased, while the malondialdehyde content significantly decreased. The liver cells became severely vacuolated and accumulated lipids in the AGPAT2 knock-down group. Comparative transcriptome analyses (AGPAT2 knock-down vs. control group) revealed 1789 differentially expressed genes (DEGs), including 472 upregulated genes and 1313 downregulated genes in the AGPAT2 knock-down group. Functional analysis showed that the main pathway of differentially expressed genes enrichment was lipid metabolism and oxidative stress, such as steroid biosynthesis, unsaturated fatty acid biosynthesis, the PPAR signaling pathway, and the P53 pathway. We used qRT-PCR to verify the mRNA expression changes of 13 downstream differential genes in related signaling pathways. These findings demonstrate that knock-down of AGPAT2 in tilapia leads to abnormal lipid metabolism and oxidative stress.
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Due to the confined mass transfer capability in microchannels, void defects are easily formed in electroformed microcolumn arrays with a high depth/width ratio, which seriously affects the life and performance of micro-devices. The width of the microchannel constantly decreases during electrodeposition, which further deteriorates the mass transfer capability inside the microchannel at the cathode. In the traditional micro-electroforming simulation model, the change of the ion diffusion coefficient is always ignored, making it difficult to accurately predict the size of void defects prior to electroforming experiments. In this study, nickel ion diffusion coefficients in microchannels are tested based on the electrochemical experiments. The measured diffusion coefficients decrease from 4.74 × 10-9 to 1.27 × 10-9 m2 s-1, corresponding to microchannels with a width from 120 to 24 µm. The simulation models of both constant and dynamic diffusion coefficients are established, and the corresponding simulation results are compared with the void defects obtained using micro-electroforming experiments. The results show that when the cathode current densities are 1, 2 and 4 A dm-2, the size of void defects obtained with the dynamic diffusion coefficient model is closer to the experimental results. In the dynamic diffusion coefficient model, the local current density and ion concentration distribution proves to be more inhomogeneous, leading to a big difference in the deposition rate of nickel between the bottom and the opening of a microchannel, and consequently a larger void defect in the electroformed microcolumn arrays. In brief, the ion diffusion coefficient inside microchannels with a different width is tested experimentally, which provides a reference for developing reliable micro-electroforming simulation models.
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This study investigated the effect of heat stress on the physiological parameters, oxidation resistance ability and immune responses in juvenile hybrid yellow catfish. Heat stress group exposed to 35 °C and control to 28 °C. Blood and liver were sampled at different hours' post-exposure. Results showed that red blood cell (RBC), white blood cell (WBC) counts, Hemoglobin (HGB) levels and hematocrit (HCT) values increased significantly (P < 0.05) post-exposure to heat stress. This indicates the increase of cell metabolism. Serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activities, total cholesterol (TC), total protein (TP), triglyceride (TG) and glucose increased significantly (P < 0.05) indicating the need to cope with stress and cell damage. Liver TC, TG, COR hormone, C3 complement increased significantly from 24 to 96 h. Heat stress mostly affects the hepatic antioxidant and immune resistance functions, resulting in increments of cortisol levels, lysozyme, superoxide dismutase (SOD), and catalase (CAT) enzyme activities. The increase of Malondialdehyde (MDA), alkaline phosphatase (AKP) indicate stimulation of the immune responses to protect the liver cells from damage. The decrease in Liver TP indicated liver impairment. Decrease in Glycogen content from 6 to 96 h indicated mobilization of more metabolites to cope with increased energy demand. Interestingly, results showed that heat stress trigged costly responses in the experimental fish like accelerated metabolism and deplete energy reserves, which could indirectly affect ability of fish to set up efficient long term defense responses against stress. These results provide insight into prevention and management of stress in juvenile hybrid yellow catfish.
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Peixes-Gato , Animais , Peixes-Gato/metabolismo , Antioxidantes/farmacologia , Imunidade Inata , Estresse Oxidativo , Resposta ao Choque Térmico , Fígado/metabolismoRESUMO
Transport is essential in cross-regional culturing of juvenile fish. Largemouth bass (Micropterus salmoides) often exhibit decreased vitality and are susceptible to disease after transportation. To study the effects of transport stress on juvenile largemouth bass, juveniles (average length: 8.42 ± 0.44 cm, average weight 10.26 ± 0.32 g) were subjected to a 12 h simulated transport, then subsequently, allowed to recover for 5 d. Liver and intestinal tissues were collected at 0, 6 and 12 h after transport stress and after 5 d of recovery. Oxidative and immunological parameters and the gut microbiome were analyzed. Hepatocytic vacuolization and shortened intestinal villi in the bass indicated liver and intestinal damage due to transport stress. Superoxide dismutase, lysozyme and complement C3 activities were significantly increased during transport stress (p < 0.05), indicating that transport stress resulted in oxidative stress and altered innate immune responses in the bass. With the transport stress, the malondialdehyde content first increased, then significantly decreased (p < 0.05) and showed an increasing trend in the recovery group. 16S rDNA analysis revealed that transport stress strongly affected the gut microbial compositions, mainly among Proteobacteria, Firmicutes, Cyanobacteria and Spirochaetes. The Proteobacteria abundance increased significantly after transport. The Kyoto Encyclopedia of Genes and Genomes functional analysis revealed that most gut microbes played roles in membrane transport, cell replication and repair. Correlation analyses demonstrated that the dominant genera varied significantly and participated in the measured physiological parameter changes. With 5 days of recovery after 12 h of transport stress, the physiological parameters and gut microbiome differed significantly between the experimental and control groups. These results provide a reference and basis for studying transport-stress-induced oxidative and immune mechanisms in juvenile largemouth bass to help optimize juvenile largemouth bass transportation.