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Pareuchiloglanis macrotrema is a glyptosternoid fish belonging to the Siluriform family and is endemic to the Qinghai-Tibet Plateau tributaries. P. macrotrema is an ideal model for studying the adaptive evolution of fish at high altitudes. P. macrotrema has two attaching livers connected to the main liver, a common feature in most Sisoridae fishes but is a special phenomenon relative to other vertebrates. Using RNA-Seq, 42 differentially expressed genes were found between the main liver and attaching liver, of which 31 were upregulated and 11 were downregulated in the main liver. The major differentially expressed genes between the main liver and attaching liver of P. macrotrema are related to metabolism, immunity, and digestive processes. Meanwhile, a comparative transcriptome analysis was carried out on P. macrotrema fish and six non-plateau Siluriformes fishes. We found 268 positively selected genes in P. macrotrema that are related to energy metabolism, immunity, and hypoxic responses. The findings of this study highlight the gene expression differences between the main liver and attaching livers of Sisoridae fishes and provide greater insight into the evolution of Tibetan fishes., (© 2022. The Author(s), under exclusive licence to Institute of Plant Genetics Polish Academy of Sciences.)

Cotesia vestalis (Hymenoptera: Braconidae) is an endoparasitoid wasp that attacks larvae of the diamondback moth, Plutella xylostella (Linnaeus), one of the most important pests of cruciferous plants in the world. This natural enemy has been used to control populations of P. xylostella. To more fully understand the molecular mechanisms of olfactory reception in C. vestalis, the transcriptomes of male antennae, female antennae, and mixed female and male legs were systematically analyzed, and the chemosensory genes were identified. A total of 253 olfactory genes, including candidates of 158 odorant receptors (ORs), 12 ionotropic receptors (IRs), 48 gustatory receptors (GRs), 22 odorant binding proteins (OBPs), 11 chemosensory proteins (CSPs), and two sensory neuron membrane proteins (SNMPs), were systematically identified and subjected to sequence and phylogenetic analysis. Then, the differentially expressed genes (DEGs) within female and male antennae were analyzed to obtain expression information on the candidate olfactory genes at the transcriptional level. The expression levels of 25 ORs, nine OBPs, eight GRs, and three IRs were significantly different between male and female antennae. Our results provide valuable information for further studies on the chemoreception mechanisms in C. vestalis, to ultimately improve the pest control measures by using natural enemies., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Schizothorax prenanti (S. prenanti), an important species of economical fish in Southwest China, is susceptible to Aeromonas hydrophila (Ah). To understand the immune response to Ah, the transcriptome profiling of spleen of S. prenanti was analyzed after Ah infection. A total of 6, 213 different expression genes (DEGs) were obtained, including 3, 066 up-regulated DEGs and 3, 147 down-regulated DEGs. These DEGs were annotated by KEGG and GO databases, so that the immune-related DEGs (IRDs) can be identified and classified. Then, the interesting IRDs were screened to build heat map, and the reliability of the transcriptome data was validated by qPCR. In order to clarify the mechanism of signal transduction in the anti-bacterial immunity, the signaling pathway initiated by TLRs was predicted. In this pathway, TLR25 and TLR5 mediate the NF-κB and AP-1 signals via MyD88-dependent pathway. Meanwhile, the type I IFN (IFNα/β) induced by IRF1 and IRF3/7 may play an important role in the anti-bacterial immunity. In conclusion, this study preliminarily provides insights into the mechanism of signal transduction after Ah infection in S. prenanti, which contributes to exploring the complex anti-bacterial immunity., (Copyright © 2018. Published by Elsevier Ltd.)

Schizothorax prenanti (S. prenanti) is an important economical cold-water fish species in southwestern China, but it is susceptible to various pathogens infection. In order to clearly elucidate the antiviral mechanism, in this study, we have analyzed the transcriptome of S. prenanti spleen after challenge with the virus mimic, poly (I:C) (pIC), using next generation sequencing technology (RNA-seq). A total of 313 differential expressed genes (DEGs) in spleen at 12 h were obtained after pIC treatment, including 268 significantly up-regulated unigenes (fold change > 2) and 45 significantly down-regulated unigenes (fold change > 2). Through the immune-related DEGs (IRDs) screening, 47 IRDs were used to establish heat map, which intuitively showed a significantly difference after pIC treatment. To validate the RNA-seq data and observe gene expression, the expression levels of 14 IRDs were detected by qPCR after pIC treatment at 0, 4, 8, 12, and 24 h. The results indicated that the qPCR data presented a positive line correlation with RNA-seq data, and the 14 IRDs were responsive to pIC stimulation except IL-1β. Thus, based on the RNA-seq and qPCR data, we inferred that MDA5- and Jak-mediated signaling pathways may involve in the antiviral signaling transduction, and induce type I IFNs and ISGs to block virus invasion, respectively. Unfortunately, TLR3 and TLR22, as receptors of virus dsRNA, were no significantly expressed in this study. Nonetheless, our study still provides useful mRNA sequences of antiviral immunity for further immunological research, and facilitates improving disease restriction in S. prenanti., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A. hydrophila is an important pathogen that mainly harms aquatic animals and has exhibited resistance to a variety of antibiotics. Here, to seek an effective alternative for antibiotics, the effects of umbelliferone (UM) at sub-MICs on A. hydrophila virulence factors and the quorum-sensing system were studied. Subsequently, RNA sequencing was employed to explore the potential mechanisms for the antivirulence activity of umbelliferone. Meanwhile, the protective effect of umbelliferone on grass carp infected with A. hydrophila was studied in vivo. Our results indicated that umbelliferone could significantly inhibit A. hydrophila virulence such as hemolysis, biofilm formation, swimming and swarming motility, and their quorum-sensing signals AHL and AI-2. Transcriptomic analysis showed that umbelliferone downregulated expression levels of genes related to exotoxin, the secretory system (T2SS and T6SS), iron uptake, etc. Animal studies demonstrated that umbelliferone could significantly improve the survival of grass carps infected with A. hydrophila, reduce the bacterial load in the various tissues, and ameliorate cardiac, splenic, and hepatopancreas injury. Collectively, umbelliferone can reduce the pathogenicity of A. hydrophila and is a potential drug for treating A. hydrophila infection. [ABSTRACT FROM AUTHOR]

As the most trait of commercial fish, increasing the growth rate of skeletal muscle is of great significance to aquaculture industry. However, the regulation of growth hormone/somatomedin (GH/IGF) growth-axis on skeletal muscle has not been effectively applied for many years, and its effect on fish and production significance for aquaculture need to be further studied. This study investigated the regulatory mechanism in sturgeon development and combined multiple organ transcriptomics revealed some common pathways emerged in the developed sturgeon including " Cytokine-cytokine receptor interaction ", " Focal adhesion" , and " Arginine and Proline Metabolism ", while many specific pathways have also been enriched in each organ. Further, all annotated GH/IGF growth-axis related genes were higher in 12 months post-fertilized sturgeon than in 24 months one, showing the potential regulation of GH/IGF growth-axis in sturgeon growth. Besides, we found that our developed hybrid F1 sturgeons with Acipenser baeri♀ and Acipenser schrenckii♂ were highly expressed in downstream of GH/IGF growth-axis than that of A. schrenckii F1 and obviously higher than A. baeri F1. The hybrid F1 with high GH/IGF growth-axis expression and high myofiber diameter also has higher growth performance. The implementation of this study proved the promotion of GH/IGF growth-axis gene on sturgeon growth, which provided a target for further development of commercial fleshy varieties in the future. • This study investigated the regulatory mechanism in sturgeon development. • Combined multiple organ transcriptomics revealed some common pathways in the developing sturgeon. • All annotated GH/IGF related genes were higher in 12 months post-fertilized sturgeon than 24 months one. • The hybrid F1 sturgeons (A. baeri♀ × A. schrenckii♂) were highly expressed in downstream of GH/IGF axis. • The hybrid F1 with high GH/IGF axis expression and high myofiber diameter has higher growth performance. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide (LPS) is a classical pathogen-associated molecular pattern that can trigger strong inflammatory response mainly by TLR4-mediated signaling pathway in mammals, but the molecular mechanism of anti-LPS immunity is unclear in teleost fishes. In this study, we analyzed the gene expression features based on transcriptome analysis in Schizothorax prenanti (S. prenanti), after stimulation with two sources of LPS from Aeromonas hydrophila and Escherichia coli (Ah. LPS and Ecoli. LPS). 921 different expression genes (DEGs) after Ah. LPS stimulation and 975 DEGs after Ecoli. LPS stimulation were acquired, but only 706 and 750 DEGs were successfully annotated into the databases, respectively. Both of two groups of DGEs were significantly enriched into immune-related pathways by KEGG enrichment analysis, such as "Toll-like receptor signaling pathway", "Cytokine-cytokine receptor interaction" and "JAK-STAT signaling pathway". The annotated DEGs from Ah. LPS and Ecoli. LPS stimulation shared 470 DEGs, including 88 immune-related DEGs (IRGs) identified mainly by KEGG enrichment to immune-related signaling pathways. Among the shared IRGs, four pattern-recognition genes (TLR5 , TLR25 , PTX3 and C1q) were induced with high expression foldchange, and IFN-γ and relative genes also showed higher expression levels than control. Meanwhile, inflammatory signals were highlighted by upregulating the expression of inflammatory cytokines (IL-1β , IL-10 and IL-8). Moreover, some non-shared IRGs (including TLR2 and TLR4) were identified, suggesting that different sources of LPS own different potentials for the induction of immune gene expression. In conclusion, TLR5, TLR25, PTX3 and C1q may function as the sensing molecules to catch the invasion signal of LPS. The anti-LPS immune response may be involved into TLR25/TLR5-mediated inflammatory signals that regulate subsequently the activation of PTX3/C1q-modulated complement pathway upon the induction of PTX3 expression, and the crosstalk between IFN-γ and TLR signaling pathways in teleost fishes. This study will contribute to further explore the molecular mechanism of LPS-induced immunity in teleost fishes. • 921 different expression genes (DEGs) after Ah. LPS stimulation and 975 DEGs after Ecoli. LPS stimulation were acquired. • The stimulation with Ah. LPS and Ecoli. LPS shared 470 DEGs including 88 immune-related DEGs (IRGs). • TLR5, TLR25, PTX3 and C1q were predicted as the potential pattern-recognition molecules in LPS sensing. • IFN-γ-mediated signaling pathway may play an important role in protecting teleost fishes against LPS. [ABSTRACT FROM AUTHOR]

The ricefield eel Monopterus albus is a protogynous hermaphroditic synbranchiform species that undergoes sequential sex change from female to male, offering an interesting model for study in the mechanisms of sequential hermaphroditism in vertebrates. To explore the expression patterns and molecular mechanisms of key genes underlying sex change in the ricefield eel M. albus , a comprehensive study of the transcriptomes of gonads at five sexual stages (ovary, early intersexual stage gonad, middle intersexual stage gonad, late intersexual stage gonad, and testis) was performed. In total, 107,260,808 raw reads and 101,886,556 clean reads were obtained, and 41,216 genes were detected in the gonad tissues. The expression levels of 21 differentially expressed genes were verified by quantitative real-time PCR (qRT-PCR) and found to be in accordance with the RNA-seq data, suggesting that the RNA-seq data were reliable. Furthermore, the expression of female-related genes decreased as sex change progressed, whereas male-related genes exhibited the opposite expression patterns. Notably, apoptosis-related genes had close relationships with sex change, including genes associated with endocytosis, calcium signaling pathways, and 7 other pathways. In particular, apoptosis signaling was delivered to the p53 network, which may be associated with sex change. Importantly, tgfb3 , fshr , camk4 and calmodulin may be the key genes, which helps balance germ cell apoptosis and proliferation during sex change. These results reveal specific molecular signatures in the gonad that are related to sex change and apoptosis signaling, which will be useful for enhancing our understanding of sequential hermaphroditism and sex change in the ricefield eel M. albus and other teleost. • Sex- and apoptosis-related genes were closely associated with sex change. • The p53 signaling pathway was most likely involved in sex change. [ABSTRACT FROM AUTHOR]

Hepatopancreatic Necrosis Syndrome (HPNS) has substantial impacts on the Chinese mitten crab Eriocheir sinensis industry. Here, transcriptome studies were used to reveal the regulatory mechanisms of HPNS. A reference hepatopancreas transcriptome of E. sinensis was de novo assembled and a transcriptome comparison was made between healthy and HPNS crabs. The results showed that HPNS within the hepatopancreas were characterized by significant energy and metabolism reactions, including glycerolipid, riboflavin, sphingolipid, and tyrosine metabolism, as well as lysosome and pancreatic secretion, vitamin digestion and absorption, melanogenesis, biotin metabolism, and fat digestion and absorption. These indicate that HPNS crabs appeared to have significant energy consumption. The apoptotic pathway in HPNS was also activated. The results showed that hepatopancreas whitening and atrophy in HPNS crabs might be related to metabolism and cell death. Further, based on the results, we hypothesized that the PDE-cAMP-related network that dominates gene expression was abnormal in HPNS crabs. The subsequent qPCR and other verification verified the transcriptome results. Besides, relevant drug irritation in vivo indicates that PDE-induced symptoms in E. sinensis were similar to those of HPNS and were affected by specific inhibitors. Therefore, the occurrence of HPNS in E. sinensis may be related to the disfunction of the PDE-cAMP-related network. Our study revealed the regulatory mechanisms and corresponding molecular regulatory strategies of HPNS that may help to elucidate the characteristics of this disease. • HPNS within the hepatopancreas were characterized by significant energy and metabolism reactions. • The PDE-cAMP-related network that dominates gene expression was abnormal in HPNS crabs. • PDE-induced symptoms were similar to those of HPNS and were affected by specific inhibitors. [ABSTRACT FROM AUTHOR]