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As the most important cultural crustacean species worldwide, studies about Pacific white shrimp (Litopenaeus vannamei) have received more attention. It has been well-documented that various pathogens could infect L. vannamei, resulting in huge economic losses. The studies about the responding mechanism of L. vannamei to sole pathogens such as Vibrio parahaemolyticus and white spot virus (WSSV) have been extensively reported, while the studies about the differently responding mechanisms remain unclear. In the present study, we identified the differently expressed genes (DEGs) of L. vannamei hemocytes post V. parahaemolyticus and WSSV infection with RNA-seq technology and compared the DEGs between the two groups. The results showed 2672 DEGs post the V. parahaemolyticus challenge (1079 up-regulated and 1593 down-regulated genes), while 1146 DEGs post the WSSV challenge (1067 up-regulated and 513 down-regulated genes). In addition, we screened the genes that simultaneously respond to WSSV and V. parahaemolyticus (434), solely respond to WSSV (1146), and V. parahaemolyticus challenge (2238), respectively. Six DEGs involved in innate immunity were quantified to validate the RNA-seq results, and the results confirmed the high consistency of both methods. Furthermore, we found plenty of innate immunity-related genes that responded to V. parahaemolyticus and WSSV infection, including pattern recognition receptors (PRRs), the proPO activating system, antimicrobial peptides (AMPs), and other immunity-related proteins. The results revealed that they were differently expressed after different pathogen challenges, demonstrating the complex and specific recognition systems involved in defending against the invasion of different pathogens in the environment. The present study improved our understanding of the molecular response of hemocytes of L. vannamei to V. parahaemolyticus and WSSV stimulation., Competing Interests: Declaration of competing interest We declare that we have no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

As a crucial member of pattern-recognition receptors (PRRs), the Tolls/Toll-like receptors (TLRs) gene family has been proven to be involved in innate immunity in crustaceans. In this study, nine members of TLR gene family were identified from the mud crab (Scylla paramamosain) transcriptome, and the structure and phylogeny of different SpTLRs were analyzed. It was found that different SpTLRs possessed three conserved structures in the TIR domain. Meanwhile, the expression patterns of different Sptlr genes in examined tissues detected by qRT-PCR had wide differences. Compared with other Sptlr genes, Sptlr-6 gene was significantly highly expressed in the hepatopancreas and less expressed in other tissues. Therefore, the function of Sptlr-6 was further investigated. The expression of the Sptlr-6 gene was up-regulated by Poly I: C, PGN stimulation and Vibrio parahaemolyticus infection. In addition, the silencing of Sptlr-6 in hepatopancreas mediated by RNAi technology resulted in the significant decrease of several conserved genes involved in innate immunity in mud crab after V. parahaemolyticus infection, including relish, myd88, dorsal, anti-lipopolysaccharide factor (ALF), anti-lipopolysaccharide factor 2 (ALF-2) and glycine-rich antimicrobial peptide (glyamp). This study provided new knowledge for the role of the Sptlr-6 gene in defense against V. parahaemolyticus infection in S. paramamosain., Competing Interests: Declaration of competing interest We declare that we have no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Toll-like receptors (TLRs) are one of the extensively studied pattern recognition receptors (PRRs) and play crucial roles in the immune responses of vertebrates and invertebrates. In this study, 14 TLR genes were identified from the genome-wide data of Octopus sinensis. Protein structural domain analysis showed that most TLR proteins had three main structural domains: extracellular leucine-rich repeats (LRR), transmembrane structural domains, and intracellular Toll/IL-1 receptor domain (TIR). The results of subcellular localization prediction showed that the TLRs of O. sinensis were mainly located on the plasma membrane. The results of quantitative real-time PCR (qPCR) showed that the detected TLR genes were differentially expressed in the hemolymph, white bodies, hepatopancreas, gills, gill heart, intestine, kidney, and salivary gland of O. sinensis. Furthermore, the present study investigated the expression changes of O. sinensis TLR genes in hemolymph, white bodies, gills, and hepatopancreas in different phases (6 h, 12 h, 24 h, 48 h) after stimulation with PGN, poly(I: C) and Vibrio parahaemolyticus. The expression of most of the TLR genes was upregulated at different time points after infection with pathogens or stimulation with PAMPs, a few genes were unchanged or even down-regulated, and many of the TLR genes were much higher after V. parahaemolyticus infection than after PGN and poly(I:C) stimulation. The results of this study contribute to a better understanding of the molecular immune mechanisms of O. sinensis TLRs genes in resistance to pathogen stimulation., Competing Interests: Declaration of competing interest We declare that we have no competing interests., (Copyright © 2024. Published by Elsevier Ltd.)

The Commd (Copper Metabolism gene MURR1 Domain) family genes play crucial roles in various biological processes, including copper and sodium transport regulation, NF-κB activity, and cell cycle progression. Their function in Haliotis discus hannai, however, remains unclear. This study focused on identifying and analyzing the Commd genes in H. discus hannai, including their gene structure, phylogenetic relationships, expression profiles, sequence diversity, and alternative splicing. The results revealed significant homology between H. discus hannai's Commd genes and those of other mollusks. Both transcriptome quantitative analysis and qRT-PCR demonstrated the responsiveness of these genes to heat stress and Vibrio parahaemolyticus infection. Notably, alternative splicing analysis revealed that COMMD2, COMMD4, COMMD5, and COMMD7 produce multiple alternative splice variants. Furthermore, sequence diversity analysis uncovered numerous missense mutations, specifically 9 in COMMD5 and 14 in COMMD10. These findings contribute to expanding knowledge on the function and evolution of the Commd gene family and underscore the potential role of COMMD in the innate immune response of H. discus hannai. This research, therefore, offers a novel perspective on the molecular mechanisms underpinning the involvement of Commd genes in innate immunity, paving the way for further explorations in this field., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A member of the immunoglobulin superfamily designated leucine-rich repeats and immunoglobulin-like domains protein-1 (lrig-1) encoding a protein with 1109 amino acids with a characteristic IGc2 domain was identified from the transcriptome data of mud crab Scylla paramamosain. Lrig-1 contained: one signaling peptide; one LRR_NT domain; nine LRR domains; three LRR_TYP domains; one LRR_CT domain; three IGc2 regions; one transmembrane region; C-terminal cytoplasmic tail. lrig-1 was widely expressed in all tissues of mud crab and was responsive in hemocytes to first and second Vibrio parahaemolyticus infections. lrig-1 knockdown mediated by RNAi repressed expression of several antimicrobial peptides significantly. Its orthologs in 19 crustacean species were identified and showed high conservation. These results suggest that lrig-1 have a vital role in mud crabs against V. parahaemolyticus infection through expression of multiple antimicrobial peptides. The results obtained in the present study imply the potential roles the lrig-1 played in immune priming in crabs., Competing Interests: Declaration of competing interest We declare that we have no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Toll-like receptors (TLRs) play essential roles in the innate immune system and have been extensively studied in mollusks. In this study, through a genome-wide search, TLR genes were identified as 29 in Haliotis discus hannai, 33 in H. rufescens, and 16 in H. laevigata. Domain analysis indicated that these TLR genes contain leucine-rich repeat (LRR) and Toll/IL-1 receptor (TIR) domains and exons ranging from 1 to 5. Polymorphism analysis showed that the TLRs in abalones did not have high diversities with 143 SNPs and no Indel in H. discus hannai, 92 SNPs and 3 Indels together with 6 missense mutations in H. rufescens, and no SNP or Indel in H. laevigata. The expression of 8 TLR genes in H. discus hannai was confirmed in the hepatopancreas, gill, hemolymph, gonads, intestine, muscle, and mantle. The expression of five TLR genes (out of 8) in gills (p < 0.05), three in hepatopancreas (p < 0.05), and three in hemolymph (p < 0.05) was upregulated separately in response to the infection caused by Vibrio parahaemolyticus. The findings in this study would contribute to a better understanding of the molecular immune mechanism of H. discus hannai against stimulation by V. parahaemolyticus and provide a basis for the study of TLRs in abalones., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Traditionally, invertebrates were thought to lack immune memory owing to a lack of acquired immune-related factors such as immunoglobulin. Nonetheless, with the in-depth consideration of invertebrate immune priming, scholars have gradually realized that the immune defenses of invertebrates are more complex than previously imagined. In the current investigation, the survival rate of Vibrio parahaemolyticus re-infected Haliotis discus hannai (VV group) was significantly different from the other groups (p < 0.05), indicating that an enhanced immune response may commence after first exposure to the same strain of V. parahaemolyticus. The transcriptome profiles of hemocytes obtained 102,052 unigenes, and 27,449 of them were annotated successfully. Venn diagram analysis showed that 2832 DEGs commonly responded to the first and second immune responses. 1734 "immune response genes" and 1460 "potential immune-enhancing genes" were also identified. A comparison of both "immune response genes" and "potential immune-enhancing genes" revealed 1019 immune-enhancing regulatory genes and 281 essential immune-enhancing genes. According to the KEGG enrichment analysis results of ERGs and EEGs, classical immune-related signaling pathways, such as NF-kappa B signaling pathway, NOD-like receptor signaling pathway, IL-17 signaling pathway, and TLR signaling pathway were significantly enriched, indicating that they were all involved in the response to V. parahaemolyticus re-infection and were likely dominant in the immune enhancement process of H. discus hannai hemocytes. The intermolecular interactions generated by Cytoscape after re-infection of V. parahaemolyticus appear more intuitively to demonstrate that hemocytes regulation was not an independent process, but rather an intricate regulatory network. H. discus hannai demonstrated enhanced immunological activity after re-infection with V. parahaemolyticus, showing immune memory in hemocytes. The current study's findings have broadened the study of immune enhancement in invertebrates and laid the framework for future research into the molecular mechanism of immune enhancement in abalones., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Long non-coding RNAs (lncRNAs) have been linked to immunological modulation. Unfortunately, little is known about the processes of immune control in shrimp. In crustaceans such as Litopenaeus vannamei, a prominent aquaculture species, the X-organ-sinus gland complex (XO-SG) in the eyestalk is an essential neuroendocrine regulatory organ. Eyestalk ablation is commonly employed in aquaculture to accelerate ovarian maturation in shrimp. It does, however, have a negative impact on the shrimps' immunocompetence and causes death. As a result, we used RNA-seq to profile the transcriptomes of L. vannamei hemocytes infected with Vibrio parahaemolyticus after the eyestalk ablation. Following strict transcript screening procedures, 2307 lncRNAs were identified from L. vannamei hemocytes in this study. Pearson correlation analysis was finally used to uncover 535 DElncRNAs and 1566 DEmRNA targets. According to the Venn diagram analysis, 326 non-eyestalk regulatory lncRNAs (NElncRNAs) with a target of 1014 non-eyestalk regulatory genes (NEmRNAs), 47 eyestalk negative regulatory lncRNAs (ENRlncRNAs) with a target of 95 eyestalk negative regulatory genes (ENRmRNAs), and 162 eyestalk positive regulatory lncRNAs (EPRlncRNAs) with a target of 457 eyestalk positive regulatory genes (EPRmRNAs) were screened. The bioinformatics analysis revealed that lncRNAs were associated with Axon regeneration, Rap1 signaling pathway, Thyroid hormone signaling pathway, TGF-beta signaling pathway, and PI3K-Akt signaling pathway, implying that lncRNAs may play a role in the regulation of the neuroendocrine-immune (NEI) system. Furthermore, several lncRNAs targeting HSP70, YWHAZ, FER2, HIF1α, and Notch were discovered and verified by qRT-PCR. These findings showed that regulation of lncRNAs in hemocytes which were controlled by the eyestalk might be one of the impact variables in controlling the differential expression of mRNAs associated with immune response in L. vannamei infected with V. parahaemolyticus., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Although many studies have shown that lncRNA, a non-coding RNA with a length of more than 200 bases, is involved in various biological functions, including the immune process, stress process, and cell development process. However, the function of lncRNA in abalone, especially in immunity, has been rarely studied. H. discus hannai and H. diversicolor are two main aquaculture abalone, and their growth is easily affected by the main pathogen Vibrio parahaemolyticus. Through rigorous screening procedures for transcripts in this study, we found that lncRNAs were 34,240, 23,022 in Haliotis diversicolor and H. discus hannai injected with V. parahaemolyticus, respectively. We also identified the unique and common lncRNAs and mRNAs of two abalone species for the first time; the shared lncRNAs and mRNAs in Haliotis diversicolor and H. discus hannai were 2352 and 13,165, respectively. Then gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the differentially expressed target genes of common and unique lncRNAs has shown that common lncRNAs could be widely involved in the biological processes of stress and cell development in both abalone species. In contrast, unique lncRNAs are linked to the Toll-like receptor, NF-kappaB signaling pathway of H. diversicolor, and pattern recognition receptors and lectins immune-related pathways of H. discus hannai. The co-expression network shows that some immune-related genes, such as INFK1, INFK2, CASP2, CASP8, IRAK1, lectin C, were closely related to lncRNAs. Further, we identified the targeted relationship between some immune-related genes and lncRNAs by qRT-PCR, through which we showed that the expression trend between targeted genes, such as INFK1 and Lnc7057, lectin C and Lnc6943, Lnc5637, and PLCG1 and Lnc1692, were consistent. In general, our results showed that lncRNA expression was induced in the two species of abalone after being infected with V. parahaemolyticus, and lncRNA was involved in the immune response of abalone by targeting coding genes., (Copyright © 2021. Published by Elsevier Inc.)

"Immune priming" plays a vital part in the immune system of invertebrates, protecting against recurrent infections by pathogens, and can provide some ideas for the prevention and treatment of invertebrate diseases. Many invertebrates have been demonstrated recently to have immune priming, but the relevant mechanisms are not known. Expression of immune system-related genes in the hemocytes and hepatopancreas of the mud crab ( Scylla paramamosain ) before and after repeated stimulation with Vibrio parahaemolyticus were analyzed by real-time fluorescence quantitative polymerase chain reaction. Some molecules that may participate in the immune priming of S. paramamosain were screened out, and their possible roles in immune priming were interpreted. Crabs injected first with heat-killed V. parahaemolyticus (HkVp group) or physiologic (0.9%) saline (PS group) were rechallenged at 168 h with live V. parahaemolyticus (HkVp+Vp group and PS+Vp group, respectively). The log-rank test shows a significant difference in survival rate between the HkVp+Vp group and the other groups after the ICH ( p < 0.05). Expression of genes involved in the toll-like receptor (TLR) signaling pathway and some antimicrobial peptide genes were detected. By, respectively, comparing gene quantification at different time points in hemocytes and the hepatopancreas, the molecules that may play a part in the early stage of the immune priming of S. paramamosain in the hemocytes are found to be down syndrome cell adhesion molecule (Dscam), Hyastatin, Cactus, Arasin, antilipopolysaccharide factor 3 (ALF3), ALF4, ALF5, and ALF6 as well as later acting molecules, such as Crustin, Dorsal, Pelle, and myeloid differentiation factor 88 (MyD88). The molecules that functioned throughout the entire period are TLR and Spaetzle. In the hepatopancreas, the molecules that may play a part in the early stages of immune priming are Dscam, Hyastatin, Arasin, ALF6, Pelle, Spaetzle, Dorsal and, in the later stage, ALF4. The molecules that functioned throughout the entire period are TLR, Crustin, Cactus, MyD88, ALF3, and ALF5. In summary, the immune function of S. paramamosain is enhanced after it receives the same repetitive stimulation by V. parahaemolyticus , indicating immune priming in S. paramamosain . Our study enriches research on immune priming in invertebrates and lays the foundation for further studies revealing the molecular mechanism of immune priming in crabs., (Copyright © 2020 Zhang, Zeng, Sun, Wang and Zhang.)

Due to increased temperatures and aquaculture density, thermal and hypoxia stresses have become serious problems for the aquaculture of abalone Haliotis diversicolor. Stresses lead to immunosuppression, which can cause severe negative impacts on aquaculture farms. To study the mechanism of immunosuppression after hypoxia stress and bacterial challenge, transcriptomes of H. diversicolor hemocytes involved in immunity were profiled. A total of 307,395,572 clean reads were generated and assembled into 99,774 unigenes. KEGG analysis indicated that 225 unigenes with immunologic function were mapped into immune-related pathways. Expression of 41 unigenes measured by quantitative real-time PCR (qRT-PCR) showed consistent results with that of transcriptome analysis. When exposure challenge of Vibrio parahaemolyticus, it is indicated that the PI3K-AKT, MAPK, NF-κB and P53 signal pathways were involved in the hypoxia-induced immunosuppression of H. diversicolor. Furthermore, when the AKT gene (HdAKT) was inhibited by double-stranded RNA (dsRNA), expression levels of HdAKT was lower than the blank and control group in hemocytes at 4 h, 12 h and 24 h (p < 0.05).

Heat-shock protein 70 (HSP70) is a molecular chaperone that plays critical roles in cell protein folding and metabolism, which helps to protect cells from unfavorable environmental stress. Haliotis diversicolor is one of the most important economic breeding species in the coastal provinces of south China. To date, the expression and transcriptional regulation of HSP70 in Haliotis diversicolor ( HdHSP70 ) has not been well characterized. In this study, the expression levels of HdHSP70 gene in different tissues and different stress conditions were detected. The results showed that the HdHSP70 gene was ubiquitously expressed in sampled tissues and was the highest in hepatopancreas, followed by hemocytes. In hepatopancreas and hemocytes, the HdHSP70 gene was significantly up-regulated by Vibrio parahaemolyticus infection, thermal stress, and combined stress ( Vibrio parahaemolyticus infection and thermal stress combination), indicating that Hd HSP70 is involved in the stress response and the regulation of innate immunity. Furthermore, a 2383 bp of 5'-flanking region sequence of the HdHSP70 gene was cloned, and it contains a presumed core promoter region, a CpG island, a (TG) 39 simple sequence repeat (SSR), and many potential transcription factor binding sites. The activity of HdHSP70 promoter was evaluated by driving the expression of luciferase gene in HEK293FT cells. A series of experimental results indicated that the core promoter region is located between -189 bp and +46 bp, and high-temperature stress can increase the activity of HdHSP70 promoter. Sequence-consecutive deletions of the luciferase reporter gene in HEK293FT cells revealed two possible promoter activity regions. To further identify the binding site of the key transcription factor in the two regions, two expression vectors with site-directed mutation were constructed. The results showed that the transcriptional activity of NF-1 site-directed mutation was significantly increased ( p < 0.05), whereas the transcriptional activity of NF-κB site-directed mutation was significantly reduced. These results suggest that NF-1 and NF-κB may be two important transcription factors that regulate the expression of HdHSP70 gene.

Mammal interleukin-1 receptor-associated kinases (IRAKs) have been demonstrated to play important functions in TLRs (Toll-like receptor) signal pathway and T cell proliferation, but there is less knowledge available on mollusc IRAKs. In this study, a molluscan IRAK-4 gene, saIRAK-4, was cloned for the first time from the small abalone (Haliotis diversicolor). Its full-length cDNA sequence was 2062 bp, with a 1548 bp open reading frame encoding a protein of 516 aa. The molecular mass of the deduced protein was approximately 57.8 kDa with an estimated pI of 5.23, and showed highest identity (47%) to acorn worm Saccoglossus kowalevskii. Amino acid sequence analysis revealed saIRAK-4 shares conserved signature motifs with other IRAK-4 proteins, including the death domain (DD), serine/threonine/tyrosine protein kinase domain (STYKc), protein kinases ATP-binding region signature, serine/threonine protein kinases active-site signature and prokaryotic membrane lipoprotein lipid attachment site. Quantitative real-time PCR was employed to investigate the tissue distribution of saIRAK-4 mRNA, and its expression in abalone under bacteria challenge and larvae at different developmental stages. The saIRAK-4 mRNA could be detected in all examined tissues, with the highest expression level in gills, and was up-regulated in hemocytes and gills after bacteria injection. Additionally, saIRAK-4 was constitutively expressed at all examined developmental stages. These results indicate that saIRAK-4 could respond to pathogenic infection and may play an important role in the adult abalone immune system and early innate immunity in the process of abalone larval development., (Copyright © 2011. Published by Elsevier Ltd.)

The X-organ-sinus gland complex (XO-SG) in the eyestalk is an important neuroendocrine regulatory organ of crustaceans such as Litopenaeus vannamei , a prominent aquaculture species. The current study found significant changes in the enzyme activities of ALP, ACP, and T-SOD of hepatopancreatic in response to Vibrio parahaemolyticus exposure following eyestalk ablation, indicating that they were all involved in the immunological regulation of shrimps against V. parahaemolyticus infection. A total of 52,656 unigenes were obtained after RNA-Seq, with an average length of 1036 bp and an N50 of 1847 bp. Subsequently, 1899 eyestalk positive regulation genes (EPRGs), 745 eyestalk negative regulation genes (ENRGs), and 2077 non-eyestalk regulatory genes (NEGs) were identified. KEGG analysis of EPRGs revealed that eyestalk ablation might activate the neuroendocrine-immune (NEI) system. The RNA-Seq data were validated using quantitative real-time PCR (qRT-PCR). The findings suggested that eyestalk ablation might affect the expression of genes involved in the prophenoloxidase-activating system, the TLR signaling pathway, and numerous other immune-related genes in L. vannamei. All of these findings revealed that the eyestalk might have a role in the immune response of L. vannamei. The genes and pathways discovered in this study will help to elucidate the molecular mechanisms of hemocytes' immune response to V. parahaemolyticus following eyestalk ablation in shrimp, as well as provide the framework for building crustacean immunity theory. • The potential role of eyestalk in the immunity of Litopenaeus vannamei to Vibrio parahaemolyticus infection was reported. • After transcriptome assembly, 52,656 unigenes with an average length of 1035,871 nt were identified. • Transcriptome analysis reveals that eyestalk plays a major role in the immunoregulation of L. vannamei. • Possible mechanism of hemocytes in response to V. parahaemolyticus infection after eyestalk ablation was clarified. [ABSTRACT FROM AUTHOR]

Abstract: The macrophage migration inhibitory factor (mif) cDNA and its genome were cloned from small abalone Haliotis diversicolor supertexta. Small abalone mif (samif) was originally identified from an expressed sequence tag (EST) fragment from a normalized cDNA library. It''s 5′ untranslated region (UTR) was obtained by 5′ rapid amplification of cDNA end (RACE) techniques and its genomic DNA was cloned by PCR. The full-length cDNA of samif was of 535 bp, consisting of a 5′-terminal UTR of 49 bp, an open reading frame of 384 bp and a 3′-terminal UTR of 102 bp. The deduced protein was composed of 128 amino acids, with an estimated molecular mass of 14.0 kDa and a predicted pI of 6.90. The full-length samif genomic DNA comprises 3238 bp, containing three exons and two introns. Real time quantitative PCR analysis revealed that samif gene is constitutively expressed in 6 selected tissues, and its expression level in hepatopancreas is higher than that in the other tissues (p < 0.01). Samif expression level in the hepatopancreas at 24 and 48 h after Vibrio parahaemolyticus injection was upregulated significantly (p < 0.01), but there was no significant change after exposure to tributyltin (TBT) (p > 0.05). [Copyright &y& Elsevier]

Antimicrobial peptide (AMP) is a crucial component of the innate immune system in crustaceans. In mud crab, Scylla paramamosain , a commercially important species, a glycine-rich antimicrobial peptide (Sp gly-AMP) gene was newly identified and putatively encoded a 26aa signal peptide and 37aa mature peptide. To understand the function of Sp gly-AMP, the expression profile of Spgly-amp gene was characterized, which showed Spgly-amp was expressed widely in most tissues of adult crabs with the highest expression level in hemocytes. After Vibrio parahaemolyticus , PGN, or Poly I:C stimulations, the expression level of Spgly - amp was significantly up-regulated in the hemocytes. In antimicrobial assays, chemically synthesized Sp gly-AMP peptides exhibited strong antibacterial activities against both Gram-positive and Gram-negative bacteria and high thermal stability after high-temperature heating. These findings in the present study verified the importance of the Sp gly-AMP in defense of pathogenic bacteria infection in the mud crab and provided a promising candidate of antimicrobial agents in the crab aquaculture. • A glycine-rich antimicrobial peptide (Sp gly-AMP) gene was newly identified from mud crab. • The orthologs of gly-AMP in several crabs are highly conserved. • After bacterial stimulations, the Spgly - amp mRNA was significantly induced in the hemocytes. • Sp gly-AMP peptides exhibit strong antibacterial activities and high thermal stability. [ABSTRACT FROM AUTHOR]

Abstract: Interleukin receptor‐associated kinase (IRAK)-1 binding protein 1 (IRAK1BP1) is a critical factor in preventing dangerous overproduction of proinflammatory cytokines by the innate immune system and in influencing the specificity of TLR responses. In this study, a first molluscan IRAK1BP1 gene, saIRAK1BP1, was cloned from the small abalone (Haliotis diversicolor). Its full-length cDNA sequence is 1047bp, with a 747bp open reading frame encoding a protein of 249 aa. The molecular mass of the deduced protein is approximately 28.1kDa with an estimated pI of 8.87, and shows highest identity (52%) to acorn worm Saccoglossus kowalevskii. Amino acid sequence analysis revealed that saIRAK1BP1 shares a conserved SIMPL domain. Quantitative real-time PCR was employed to investigate the tissue distribution of saIRAK1BP1 mRNA, and its expression in abalone under bacteria challenge and larvae at different developmental stages. The saIRAK1BP1 mRNA could be detected in all examined tissues, with the highest expression level in hemocytes, and was up-regulated in gills, kidneys and hemocytes after bacteria injection. Additionally, saIRAK1BP1 was constitutively expressed at all examined developmental stages. These results indicate that saIRAK1BP1 play an important role in the adult abalone immune system and might be essential in embryo and larval development in abalone. [Copyright &y& Elsevier]

Abstract: Insulin-like growth factor binding protein 7 (IGFBP7), the only member of the IGFBP superfamily that binds strongly to insulin, may have different functions from other IGFBPs. Unlike other IGFBPs, there is no knowledge available on aquatic invertebrate IGFBP7. In this study, a molluscan IGFBP7 gene, saIGFBP7, was cloned for the first time from the small abalone Haliotis diversicolor. Its full-length cDNA sequence is 1812bp, with a 720bp open reading frame encoding a protein of 239 aa. The molecular mass of the deduced protein is approximately 25.37kDa with an estimated pI of 5.00, and it shares highest 41% identity to IGFBP7 of Amblyomma americanum. Analysis of conserved domains revealed the presence of an IGFBP N-terminal domain (IB), a kazal-type serine proteinase inhibitor domain (KI), and an immunoglobulin-like C2 domain (IgC2) in saIGFBP7. Furthermore, the 12 cysteine residues and the signature amino acid motif ‘xCGCCxxC’ which are characterized by the amino terminus region of the IGFBP superfamily are all presented in saIGFBP7. Quantitative real-time PCR and western blot were employed to investigate the tissue distribution of saIGFBP7, and its expression under bacterial challenge. The saIGFBP7 mRNA and protein could be detected in all examined tissues, with the highest expression level in hemocytes, higher expression level in gills, and was up-regulated in hemocytes and gills after bacterial injection. In addition, saIGFBP7 mRNA transcripts were observed in a subset of the branchial epithelium and the nucleus of hemocytes using the in situ hybridization method. Interestingly, saIGFBP7 was detected mainly in the goblet-like cell of the branchial epithelium by immunohistochemistry. These results suggested that saIGFBP7 was likely to be involved in a function associated with pathogenic infection and may play an important role in the adult abalone immune system. [Copyright &y& Elsevier]

Genes encoding for Toll-like receptors (TLRs) provide innate immunity to aquatic organisms. The function of TLRs in innate immunity has been characterized in several crustacean species; however, systematic information on TLRs is still scarce in the Pacific white shrimp (Litopenaeus vannamei). Here, we conducted a genome-wide study of TLR genes for the first time in Pacific white shrimps. A total of 11 TLR genes were recognized. Analysis of the architecture domain revealed that most TLR genes possessed three major domains: a Toll/interleukin receptor (TIR) domain, a transmembrane domain (TM), and multiple leucine-rich repeat domains (LRRs). Results revealed that all 11 TLR genes were ubiquitously expressed in all the tested tissues. Furthermore, the expression of 11 TLR genes after Vibrio parahaemolyticus infection was measured in hemocytes, hepatopancreas, and gills. The results showed that most genes were significantly up regulated at different time points, except for TLR-Tollo1 and TLR-Tollo2 in hepatopancreas, and TLR13× isoform, TLR3, TLR4, and PTL-2 in gills. Our study provided the first genome-wide systemic analysis of Pacific white shrimp and suggested that TLR genes play significant roles in the L. vannamei immune response. These findings will offer evidence for the functional study of L. vannamei TLRs and could facilitate the investigation of molecular mechanisms underlying the immune regulation of L. vannamei challenged by V. parahaemolyticus , which will consequently contribute to the sustainability of aquaculture. • A total of 11 TLR genes were identified from the genome of pacific white shrimp (L. vannamei). • Their structural domain, subcellular location and N-glycosylation site were identified. • TLR genes were ubiquitously expressed in all the examined healthy tissues with high expression in hepatopancreas and gill. • The expression of TLR genes in the tested tissues were up regulated after bacterial infection at different time points. [ABSTRACT FROM AUTHOR]