ObjectivesTo investigate the lncRNA profiling during tilapia peritoneal macrophages (TPMs) activation and discuss the relationship between lncRNA and mRNA.Materials and MethodsRNA sequencing was used to investigate the lncRNA and mRNA profiles of TPMs activation following stimulation with Streptococcus agalactiae (Sa) antigen, heat shock protein 70 (HSP70) and HSP70+Sa. The expressions of lncRNA and mRNA were confirmed by qPCR. 356 lncRNA, 10173 mRNA and 1782 transcripts of uncertain coding potential (TUCP) were differentially expressed by pairwise comparison. These lncRNAs were shorter in length, fewer in exon number and higher in expression levels as compared with mRNAs. 683 lncRNAs and 4320 mRNAs were co-located, while 316 lncRNAs and 9997 mRNAs were in co-expression networks. Seven mRNAs (ANKRD34A, FMODA, GJA3, CNTN5, BMP10, BAI2 and HS3ST6) were involved in both networks of LNC_00035 and LNC_000466. Differentially expressed genes were involved in signaling pathways, such as “phosphorylation”, “cytokine-cytokine receptor interaction”, “endocytosis” and “MHC protein complex”. LNC_000792, LNC_000215, LNC_000035 and LNC_000310, with cis and/or trans relationships with mRNAs, were also involved in ceRNA network.ConclusionsThese results might represent the first identified expression profile of lncRNAs and mRNAs in tilapia macrophages activated by HSP70 and Sa.

To characterize the cold tolerance mechanism of the Pacific white shrimp (Litopenaeus vannamei), we performed single-cell RNA sequencing (scRNA-seq) of ∼5185 hepatopancreas cells from cold-tolerant (Lv-T) and common (Lv-C) L. vannamei at preferred and low temperatures (28°C and 10°C, respectively). The cells fell into 10 clusters and 4 cell types: embryonic, resorptive, blister-like, and fibrillar. We identified differentially expressed genes between Lv-T and Lv-C, which were mainly associated with the terms “immune system,” “cytoskeleton,” “antioxidant system,” “digestive enzyme,” and “detoxification,” as well as the pathways “metabolic pathways of oxidative phosphorylation,” “metabolism of xenobiotics by cytochrome P450,” “chemical carcinogenesis,” “drug metabolism-cytochrome P450,” and “fatty acid metabolism.” Reconstruction of fibrillar cell trajectories showed that, under low temperature stress, hepatopancreas cells had two distinct fates, cell fate 1 and cell fate 2. Cell fate 1 was mainly involved in signal transduction and sensory organ development. Cell fate 2 was mainly involved in metabolic processes. This study preliminarily clarifies the molecular mechanisms underlying cold tolerance in L. vannamei, which will be useful for the breeding of shrimp with greater cold tolerance.

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The yellowfin seabream, Acanthopagrus latus Houttuyn 1782, is a commercially and ecologically important species and a good model for studies of sexual differentiation. In this study, the complete mitochondrial genome of A. latus has been determined, which is 16,635 base pairs (54.3% A þ T content) in length and consists of 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and a 948 bp D-loop region. The phylogenetic analyses showed that A. latus has a close relationship with Acanthopagrus schlegelii Bleeker 1854.

The mudskipper, Boleophthalmus pectinirostris ( B. pectinirostris ), is an amphibious fish that lives in the intertidal mudflats. It is a cultured economic fish with nutritional and pharmacological value. Here, we report the complete mitochondrial genome sequence of B. pectinirostris , which is 17,111 base pairs (55.3% A + T content) in length and consists of 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs, and a 1453 bp D-loop region. The complete mitochondrial genome of B. pectinirostris will provide useful genetic information for future phylogenetic and taxonomic classification of B. pectinirostris .