Transcriptome Analysis Reveals Immune and Antioxidant Defense Mechanisms in the Eriocheir japonica sinensis after Exposure to Ammonia.

As a key species in freshwater aquaculture, Eriocheir japonica sinensis was subjected to ammonia stress to assess its impact on the hepatopancreas. A total of 4007 differentially expressed genes (DEGs) were identified between control and treatment groups, comprising 1838 upregulated and 2169 downregulated genes. Following exposure to 300 mg/L of ammonia, the oxidative phosphorylation pathway was activated, while the lysosomal pathway was suppressed, thereby influencing immune functions. Thirteen DEGs from these pathways were further validated via qRT-PCR, revealing gene expression changes of one- to two-fold. Both acid phosphatase (ACP) and alkaline phosphatase (AKP) levels in the hepatopancreas and hemolymph initially increased and then decreased, indicating a disruption in immune functionality. Additionally, alanine transaminase (ALT) and triglyceride (TG) levels were measured, alongside catalase (CAT) activity, total antioxidant capacity (T-AOC), and malondialdehyde (MDA) content, all of which showed an upward trend, signifying oxidative stress and tissue damage. These results offer critical insights into the antioxidant and immune mechanisms of E. j. sinensis in ammonia-enriched environments.

Transcriptome analysis provides new insight into the mechanism of Bombyx mori under zinc exposure.

Zinc is a significant source of heavy metal pollution that poses risks to both human health and biodiversity. Excessive concentrations of zinc can hinder the growth and development of insects and trigger cell death through oxidative damage. The midgut is the main organ affected by exposure to heavy metals. The silkworm, a prominent insect species belonging to the Lepidoptera class and widely used in China, serves as a model for studying the genetic response to heavy metal stress. In this study, high-throughput sequencing technology was employed to investigate detoxification-related genes in the midgut that are induced by zinc exposure. A total of 11,320 unigenes and 14,723 transcripts were identified, with 553 differentially expressed genes (DEGs) detected, among which 394 were up-regulated and 159 were down-regulated. The Gene Ontology (GO) analysis revealed that 452 DEGs were involved in 18 biological process subclasses, 14 cellular component subclasses and 8 molecular functional subclasses. Furthermore, the KEGG analysis demonstrated enrichment in pathways such as Protein digestion, absorption and Lysosome. Validation of the expression levels of 9 detoxification-related DEGs through qRT-PCR confirmed the accuracy of the RNA-seq results. This study not only contributes new insights into the detoxification mechanisms mechanism of silkworms against zinc contamination, but also serves as a foundation basis for understanding the molecular detoxification processes in lepidopteran insects.

Correlative analysis of transcriptome and 16S rDNA in Procambarus clarkii reveals key signaling pathways are involved in Chlorantraniliprole stress response by phosphoinositide 3-kinase (PI3K).

Chlorantraniliprole (CAP), a diamide insecticide, is extensively used in agricultural production. With the increasing adoption of the rice-crayfish integrated farming model, pesticide application has become more frequent. However, the potential risk of CAP to crayfish (Procambarus clarkii) remains unclear. In this study, crayfish were exposed to 30, 60, 90 mg/L CAP for 96 h. As CAP exposure time and concentration increased, crayfish survival rates and total hemocyte counts (THC) decreased. Biochemical indicators revealed that CAP exposure induced oxidative stress and immunosuppression in crayfish, leading to metabolic disorders and reduced ATP content. Additionally, pathological analysis and 16S rDNA sequencing demonstrated that CAP exposure compromised the intestinal barrier of crayfish, altered the intestinal microbial community structure, and caused apoptosis. Differential gene expression analysis showed that CAP exposure significantly suppressed the expression of genes related to immune and energy metabolism pathways, resulting in immune dysfunction and insufficient energy supply, while activating the PI3K/AKT/mTOR signaling pathway. PI3K knockdown reduced antioxidant and digestive activities, increased the expression of proinflammatory and apoptosis genes, and exacerbated CAP-induced intestinal toxicity. This study is the first to explore the characterization and function of PI3K in crustaceans, providing new insights for further research on crustacean antioxidants and defense mechanisms.

Ferritin Heavy-like subunit is involved in the innate immune defense of the red swamp crayfish Procambarus clarkii.

Iron-binding proteins, known as ferritins, play pivotal roles in immunological response, detoxification, and iron storage. Despite their significance to organisms, little is known about how they affect the immunological system of the red swamp crayfish (Procambarus clarkii). In our previous research, one ferritin subunit was completely discovered as an H-like subunit (PcFeH) from P. clarkii. The full-length cDNA of PcFerH is 1779 bp, including a 5'-UTR (untranslated region, UTR) of 89 bp, 3'-UTR (untranslated region, UTR) of 1180 bp and an ORF (open reading frame, ORF) of 510 bp encoding a polypeptide of 169 amino acids that contains a signal peptide and a Ferritin domain. The deduced PcFerH protein sequence has highly identity with other crayfish. PcFerH protein's estimated tertiary structure is quite comparable to animal structure. The PcFerH is close to Cherax quadricarinatus, according to phylogenetic analysis. All the organs examined showed widespread expression of PcFerH mRNA, with the ovary exhibiting the highest levels of expression. Additionally, in crayfish muscles, intestines, and gills, the mRNA transcript of PcFerH was noticeably up-regulated, after LPS and Poly I:C challenge. The expression of downstream genes in the immunological signaling system was suppressed when the PcFerH gene was knocked down. All of these findings suggested that PcFerH played a vital role in regulating the expression of downstream effectors in the immunological signaling pathway of crayfish.

Transcriptomic analysis provides insights into the immune responsive genes in the Procambarus clarkii hepatopancreas challenged with Vibrio parahaemolyticus.

Procambarus clarkii is an economically important species in China; however, its high mortality rate due to pathogenic bacteria, particularly Vibrio parahaemolyticus, results in significant economic loss. This study aimed to understand the immune response of crayfish to bacterial infection by comparing and analyzing transcriptome data of hepatopancreatic tissue from P. clarkii challenged with V. parahaemolyticus or treated with PBS. Physiological indices (TP, Alb, ACP, and AKP) were analyzed, and tissue sections were prepared. After assembling and annotating the data, 18,756 unigenes were identified. A comparison of the expression levels of these unigenes between the control and V. parahaemolyticus groups revealed 4037 DEGs, with 2278 unigenes upregulated and 1759 downregulated in the V. parahaemolyticus group. GO (Gene Ontology) enrichment analysis shows that the DGEs are mainly enriched in cellular anatomical activity, bindinga and cellular process, enrichment analysis of KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways showed that DGEs were mainly enriched in Base excision repair, Phagosome and Longevity regulating pathway. At the same time, lysosome was also enriched. The phagosome and lysosome pathways play a crucial role in the immune defense of crayfish against V. parahaemolyticus injection that will be highlighted. In addition, the expression levels of six selected immune-related DEGs were measured using qRT-PCR, which validated the results of RNA-seq analysis. This study provides a new perspective on the immune system and defense mechanisms of P. clarkii and a valuable foundation for further investigation of the molecular immune mechanisms of this species.

Insights into chlorantraniliprole exposure via activating cytochrome P450-mediated xenobiotic metabolism pathway in the Procambarus clarkii: Identification of P450 genes involved in detoxification.

To investigate the impact of chlorantraniliprole on Procambarus clarkii, acute toxicity tests were performed. Results indicated that 96 h post-exposure to chlorantraniliprole (60 mg/L) led to the separation of the hepatopancreas basement membrane, causing cell swelling, rupture, and vacuolation. Moreover, acid phosphatase (ACP) and alkaline phosphatase (AKP) activities exhibited divergent trends across four concentrations of chlorantraniliprole (0, 30, 60, and 90 mg/L). Hydrogen peroxide (H2O2) and catalase (CAT) levels significantly increased, while total superoxide dismutase (T-SOD) and malonaldehyde (MDA) activities decreased, indicating oxidative stress in the hepatopancreas. A total of 276 differentially expressed genes (DEGs) were identified, with 204 up-regulated and 72 down-regulated. Out of these, 114 DEGs were successfully annotated and classified into 99 pathways, with a primary focus on the cytochrome P450-mediated xenobiotic metabolism pathway. The DEGs enriched in this pathway, along with transcriptome data, were validated using quantitative-polymerase chain reaction. This study enhances the transcriptome database of P. clarkii and provides fundamental insights into its immune defense and antioxidant mechanisms. Additionally, it lays a theoretical foundation for future research on disease prevention in P. clarkii within rice-shrimp culture systems.

Transcriptome Analysis Reveals Antioxidant Defense Mechanisms in the Silkworm Bombyx mori after Exposure to Lead.

Lead (Pb) is a major source of heavy metal contamination, and poses a threat to biodiversity and human health. Elevated levels of Pb can hinder insect growth and development, leading to apoptosis via mechanisms like oxidative damage. The midgut of silkworms is the main organ exposed to heavy metals. As an economically important lepidopteran model insect in China, heavy metal-induced stress on silkworms causes considerable losses in sericulture, thereby causing substantial economic damage. This study aimed to investigate Pb-induced detoxification-related genes in the midgut of silkworms using high-throughput sequencing methods to achieve a deeper comprehension of the genes' reactions to lead exposure. This study identified 11,567 unigenes and 14,978 transcripts. A total of 1265 differentially expressed genes (DEGs) were screened, comprising 907 upregulated and 358 downregulated genes. Subsequently, Gene Ontology (GO) classification analysis revealed that the 1265 DEGs were distributed across biological processes, cellular components, and molecular functions. This suggests that the silkworm midgut may affect various organelle functions and biological processes, providing crucial clues for further exploration of DEG function. Additionally, the expression levels of 12 selected detoxification-related DEGs were validated using qRT-PCR, which confirmed the reliability of the RNA-seq results. This study not only provides new insights into the detoxification defense mechanisms of silkworms after Pb exposure, but also establishes a valuable foundation for further investigation into the molecular detoxification mechanisms in silkworms.

The analyses of the complete mitochondrial genomes of three crabs revealed novel gene rearrangements and phylogenetic relationships of Brachyura.

BACKGROUND: Brachyura crab is the largest branch of Decapoda crustacean. Phylogenetic relationships within Brachyura remain controversial to be investigated. The mitochondrial genome (mitogenome) is an important molecular marker for studying the phylogenetic relationships of Brachyura. METHODS AND RESULTS: To understand the phylogeny of Brachyura, the three complete mitogenomes from Charybdis annulata, Leptodius exaratus, and Spider crab were sequenced and annotated. Their full length was 15,747, 15,716, and 16,608 bp long, respectively. The first two crabs both contained 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a control region. However, Spider crab contained 13 PCGs, two rRNA genes, 25 tRNA genes and a control region. The mitogenomes of each of the three crabs exhibited high AT content (67.8%, 69.1%, and 70.8%), with negative AT skews (-0.014, - 0.028, and - 0.017) and GC skews (-0.269, - 0.286, and - 0.341). The gene order of C. annulata was identical to the ancestor of Brachyura. Compared with the ancestor of Brachyura, L. exaratus exhibited the gene rearrangements of Val (V)-rrnS-control region, and Spider crab had the four copies of Lys (K). Phylogenetic analyses indicated that C. annulata belonged to Portunidae family, Portunoidea superfamilies, L. exaratus belonged to Xanthidae family, Xanthoidea superfamilies, and Spider crab belonged to Mithracidae family, Majoidea superfamilies. Phylogenetic analyses showed that the two species (Somanniathelphusa boyangensis and Huananpotamon lichuanense) belonging to the Potamoidea were sister groups to the Thoracotremata, thus supporting the conclusion that Heterotremata is polyphyletic. CONCLUSION: The results of this study enriched the crab mitogenome database and enabled us to better understand the phylogenetic relationships of Brachyura.

Complete mitochondrial genome of Parasa sinica: New insights into the phylogeny of Limacodidae.

In this study, the whole mitochondrial genome (mitogenome) of Parasa sinica was sequenced. It contains 15,306 base pairs (bp), 13 protein-coding genes (PCGs), two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and one non-coding regulatory area (CR), all of which are shared by other lepidopterans. It follows the same gene order as ordinary lepidopterans. Further, out of these 37 genes, 23 are present on the heavy strand whereas the remaining 14 are located on the light strand. The A + T composition of the mitogenome is relatively high. Although P. sinica has a negative AT-skew and GC-skew, the GC-skew value is significantly lower than the AT-skew value. All PCGs, with the exception of CO1, carry the same start codon (ATN). All tRNAs exhibit the usual cloverleaf secondary structure. We identified the conserved motif "ATAGA + poly-T″ found in other lepidopteran insects at the beginning of the CR. We collected the concatenated PCGs sequences in the mitochondrial genome of 15 species of Zygaenoidea, with the sequences of Geometridae as outgroups, including P. sinica, and constructed phylogenetic trees using Bayesian inference (BI) and maximum likelihood (ML) methods. The monolineage of each superfamily is usually well supported. Based on phylogenetic analysis, P. sinica is a member of family Limacodidae, strongly supporting the monophyly of the Zygaenoidea groups.

Bombyx mori transcription factor, E74A, beneficially affects BmNPV infection through direct interaction.

BACKGROUND: Nucleopolyhedrovirus (NPV), one of the baculoviruses, is a promising biopesticide for pest control. Lepidopteran account for 70% of pests, therefore investigation on highly conserved genes associated with viral infections in the lepidopteran model, the silkworm, will serve as a valuable reference for improving the effectiveness of pest management. BmE74A is a member of the erythroblast transformation-specific (ETS) family of transcription factors in Bombyx mori, which we previously found to be highly conserved and closely associated with BmNPV. This study aimed to elucidate the role of BmE74A in viral infection. RESULTS: A significantly high expression of BmE74A in eggs indicated its important role in embryonic development, as did relatively high expressions in the hemolymph and midgut. Significant differences in BmE74A expression in different resistant strains after BmNPV infection suggested its involvement as a response to viral infection. Moreover, RNA interference (RNAi) and overexpression experiments confirmed the important role of BmE74A in promoting viral infection. BmNPV infection was significantly suppressed and enhanced by BmE74A knockdown and overexpression, respectively. Besides, BmE74A was found to regulate the expression of BmMdm2 and Bmp53. Furthermore, the binding of ETS, the functional domain of BmE74A, to occlusion-derived virus proteins was confirmed by far-western blotting, and four viral proteins that may interact with ETS proteins were identified by mass spectrometry. Similarly, a homolog of BmE74A in Spodoptera litura was also found to be involved in larval susceptibility to BmNPV. CONCLUSION: BmE74A promotes BmNPV proliferation by directly interacting with the virus, which may be related to the suppression of the p53 pathway. © 2022 Society of Chemical Industry.

Integrins in the Immunity of Insects: A Review.

Integrins are a large group of cell-surface proteins that are classified as transmembrane proteins. Integrins are classified into different types based on sequence variations, leading to structural and functional diversity. They are broadly distributed in animals and have a wide range of biological functions such as cell-to-cell communication, intracellular cytoskeleton organization, cellular signaling, immune responses, etc. Integrins are among the most abundant cell surface proteins in insects, exhibiting their indispensability in insect physiology. Because of their critical biological involvement in physiological processes, they appear to be a novel target for designing effective pest control strategies. In the current literature review, we first discuss the discovery and expression responses of integrins against various types of pathogens. Secondly, we examine the specific biological roles of integrins in controlling microbial pathogens, such as phagocytosis, encapsulation, nodulation, immune signaling, and so on. Finally, we describe the possible uses of integrins to control agricultural insect pests.

Differentially expressed genes in head kidney of Pelteobagrus fulvidraco following Vibrio cholerae challenge.

The yellow catfish (Pelteobagrus fulvidraco) is a freshwater fish with high economic value in eastern China. Nevertheless, pathogens causing bacterial diseases in P. fulvidraco have brought about huge economic loss and high mortality in artificial aquaculture. For disease control, it is critical to further understand the immune system of yellow catfish and immune-related genes with which they respond to pathogenic infections. In this study, high-throughput sequencing methods were used to analyze the transcriptomic spectrum of the head kidney from P. fulvidraco challenged by Vibrio cholera. A total of 45,544 unique transcript fragments (unigenes) were acquired after assembly and annotation, with an average length of 1,373 bp. Additionally, 674 differentially expressed genes (DEGs) were identified after stimulation with V. cholerae, 353 and 321 genes were identified as remarkably up- or downregulated, respectively. To further study the immune-related DEGs, we performed KEGG enrichment and GO enrichment. The results showed gene regulation of response to stimulus, immune response, immune system progress, response to external stimuli and cellular response to stimuli. Analysis of KEGG enrichment is important to identify chief immune related pathways. Real-time quantitative reverse transcription-PCR (qRT-PCR) results indicated 10 immune response genes that were found to be upregulated compared to a control group after 6 h of V. cholerae challenging. In summary, the results of our study are helpful to determine the defense mechanisms and immune system responses of yellow catfish in reaction to bacterial challenges.

Transcriptome analysis reveals antioxidant defense mechanisms in the red swamp crayfish Procambarus clarkia after exposure to chromium.

Chromium (Cr) as a chromate anion has a strong redox capacity that seriously threatens the ecological environment and human health. Cr can contaminate water and impart toxicity to aquatic species. Procambarus clarkii is an important food source that once represented a large proportion of the aquaculture industry due to its rapid reproduction and high economic value. However, there have been reports on the death of P. clarkii due to heavy metal pollution. The underlying mechanism regarding heavy metal toxicity was studied in this paper. The transcriptome data of hemocytes extracted from P. clarkii injected with Cr were analyzed by high-throughput sequencing and compared to the control group. In total, 48,128,748 clean reads were obtained in the treatment group and 56,480,556 clean reads were obtained in the control group. The reads were assembled using Trinity and the identified unigenes were then annotated. Then, 421 differentially-expressed genes (DEGs) were found, 170 of which were upregulated and 251 downregulated. Many of these genes were found to be related to glutathione metabolism and transportation. The glutathione metabolic pathway of P. clarkii was thus activated by Cr exposure to detoxify and maintain body function. Validation of DEGs with quantitative real-time PCR confirms the changes in gene expression. Thus, this study provides data supporting a glutathione-focused response of P. clarkii to exposure to heavy metals.

Transcriptome analysis of differentially expressed genes in the red swamp crayfish Procambarus clarkii challenged with Aeromonas hydrophila.

As an important economic species in China, aquaculture of the crayfish Procambarus clarkii has suffered huge losses due to infection by pathogenic bacteria, mainly by Aeromonas hydrophila, which leads to high mortality and huge economic loss. To better understand the immune response of crayfish against bacterial infection, we compared and analyzed transcriptome data of hepatopancreatic tissue from P. clarkii that were either challenged with A. hydrophila or treated with PBS. After assembly and annotation of the data, 32,041 unigenes with an average length of 1512 base pairs were identified. Compared to control group, Differential gene expression (DEG) analysis revealed 608 DEGs were obtained, of which 274 unigenes were upregulated and 334 were downregulated in the A. hydrophila group. Furthermore, the expression levels of eight selected immune-related DEGs were validated by qRT-PCR, substantiating the reliability of RNA-seq results. This study not only provides effective data support for immune defense strategies of P. clarkii in response to bacterial infections, but also provides new information about the P. clarkii immune system and defense mechanisms, and a valuable basis for further studies to elucidate the molecular immune mechanisms of this species.

Bmcas-1 plays an important role in response against BmNPV infection in vitro.

Apoptosis, as one kind of innate immune system, is involved in host response against pathogens innovation. Caspases play a vital role in the execution stage of host cell apoptosis. It has been reported that Bmcaspase-1 (Bmcas-1) has a close relationship with Bombyx mori nucleopolyhedrovirus (BmNPV) infection for its differentially expressed patterns after viral infection. However, its underlying response mechanism is still unclear. The significant differential expression of Bmcas-1 in different tissues of differentially resistant strains revealed its vital role in BmNPV infection. To further validate its role in BmNPV infection, budded virus (BV)-eGFP was analyzed after knockdown and overexpression of Bmcas-1 by small interfering RNA and the pIZT-mCherry vector, respectively. The reproduction of BV-eGFP obviously increased at 72 h after knockdown of Bmcas-1, and decreased after overexpression in BmN cells. Moreover, the conserved functional domain of Cas-1 among different species and the closed evolutionary relationship of Cas-1 in Lepidoptera hinted that Bmcas-1 might be associated with apoptosis, and this was also validated by the apoptosis inducer, Silvestrol, and the inhibitor, Z-DEVD-FMK. Therefore, Bmcas-1 plays an essential antiviral role by activating apoptosis, and this result lays a fundament for clarifying the molecular mechanism of silkworm in response against BmNPV infection and breeding of resistant strains.

Differentially expressed genes involved in immune pathways from yellowhead catfish (Tachysurus fulvidraco) after poly (I:C) challenge.

Yellowhead catfish (Tachysurus fulvidraco) is an important aquaculture fish species in China with a high market value. Infectious diseases pose serious threats in farmed fish species, and although vaccines can prevent certain infections, they rely on potent adjuvants. In this study, we analyzed the transcriptomic profiles of spleens from poly (I:C)-treated T. fulvidraco. We obtained 46,362,922 reads corresponding to 490,926 transcripts and 318,059 genes. Gene annotation using different databases and subsequent differential gene expression analyses led to the identification of 5587 differentially expressed genes (DEGs), of which 2473 were up-regulated and 3114 were down-regulated in poly (I:C)-treated fish. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEGs revealed the significant dysregulation of immune- and cancer-related genes in the spleens of poly (I:C)-treated fish. Notably, several components of JAK-STAT, MAPK, and p53 signaling pathways were significantly dysregulated in response to poly (I:C) treatment. Quantitative real-time PCR (qRT-PCR) analysis of 11 randomly selected immune response genes confirmed the reliability of our findings. In conclusion, our findings provide novel insight into the immune responses of T. fulvidraco and suggest that poly (I:C) may represent a promising adjuvant of fish vaccines.

Transcriptome analysis of immune-related genes in Sesarmops sinensis hepatopancreas in reaction to peptidoglycan challenge.

Sesarmops sinensis is a dominant omnivorous crab species, which plays an important ecological function in salt marsh ecosystems. To better understand its immune system and immune related genes under pathogen infection, the transcriptome was analyzed by comparing the data of S. sinensis hepatopancreas stimulated by PBS and PGN. A set of assembly and annotation identified 39,039 unigenes with an average length of 1105 bp, obtaining 1300 differentially expressed genes (DEGs) in all, which included 466 remarkably up-regulated unigenes and 834 remarkably down-regulated unigenes. In addition, based on mensurable real time-polymerase chain reaction and high-throughput sequencing, several immune responsive genes were found to be markedly up-regulated under PGN stimulation. In conclusion, in addition to enriching the existing transcriptome data of S. sinensis, this study also clarified the immune response of S. sinensis to PGN stimulation, which will help us to further understand the crustacean's immune system.

Chitinase involved in immune regulation by mediated the toll pathway of crustacea Procambarus clarkii.

Chitinase can degrade chitin and play an essential role in animal immunity and plant defense. The immune functions of Chitinase in Procambarus clarkii (P. clarkii) remain to elucidate. Here, we identified PcChitinase 2 gene sequence from P. clarkii and studied its spatial and temporal expression profiles. The PcChitinase 2 transcribed unequally in different tissues; however, its expression was highest in those of stomach, gut, and hepatopancreas. The challenge with lipolysaccharide or peptidoglycan significantly up-regulated the expression of PcChitinase 2 in hepatopancreas. The knockdown of the PcChitinase 2 gene by double-stranded RNA suppressed most of the Toll-pathway-related immune genes (phospholipase, lectin, sptazle Cactus, serine proteikinase, anti-lipopolysaccharide factor, and Toll) production were significantly increased. Our results suggest PcChitinase 2 may be involved in the innate immune responses of P. clarkii by modulating the toll pathway.

A complement factor I (CFI) gene mediates innate immune responses in yellow catfish Pelteobagrus fulvidraco.

This study isolated CFI gene from Pelteobagrus fulvidraco and named it PfCFI. The cDNA of PfCFI is 2374 bp long, including a 52 bp 5' untranslated sequence, a 222 bp 3' untranslated sequence, and an open reading frame (ORF) of 2100 bp encoding polypeptide consisting of 699 amino acids. Phylogenetic analysis revealed that the PfCFI was closely related to CFI of Ictalurus punctatus. Real-time quantitative reverse transcription-PCR (qRT-PCR) analysis indicate that there is the PfCFI gene which expressed in all the rest of tested tissues in varied levels, and mainly distributed in liver and least in heart. The reseachers induce the expressions level of PfCFI gene in liver, spleen, head kidney and blood at different points in time after challenged with lipopolysaccharide (LPS), and polyriboinosinic polyribocytidylic acid (poly I:C), respectively. Together these results suggested that CFI gene plays an important role in resistance to pathogens in yellow catfish immunity.

Phylogenetic relationships of Grapsoidea and insights into the higher phylogeny of Brachyuran.

Decapoda is one of the most diverse crustacean orders, and has become an important research subject. However, the phylogenetic relationships among the main lineages of Decapoda remain uncertain, especially in the order Brachyura. Herein, we sequenced the whole mitochondrial genome of V. litterata and constructed a phylogenetic tree to understand its phylogenetic relationships with other species. The results showed that the mitochondrial genome of V. litterata was generally similar to mitogenomes of Metazoa reported in the literature, with a size of 16,247 bp, 37 genes, and a control region. Both AT-skew and GC-skew were negative, indicating more abundant Cs and Ts than Gs and As. The gene arrangement of V. litterata is identical to those of Eriocheir hepuensis, Cyclograpsus granulosus, Hemigrapsus sanguineus, Helicana wuana, and Helice tientsinensis but differs from the pancrustacean ground pattern and typical arrangement of Brachyuran crabs. Phylogenetic reconstruction showed that V. litterata belongs to the Varunidae.