Pampus Argenteus Research Articles

The regulation of ovarian degeneration in Pampus argenteus by heat shock protein genes under low-temperature stress.

Temperature is a crucial environmental factor that significantly impacts the growth, development, metabolism, and physiological functions of fish. To study the effects of low-temperature on the gonadal development of silver pomfret (Pampus argenteus), a cold period by gradually lowering the water temperature from 18°C to 9°C was simulated. The results showed that hsp70, hsp90a, and hsp90b were widely expressed in the tissues of P. argenteus, with hsp70 primarily expressed in the pituitary, hsp90a and hsp90b mainly expressed in the lateral. The hsps were involved in the development process of P. argenteus from 1 to 27 days post-hatching (dph). The expression levels of hsp70 and hsp90b were highest at 17 dph, while the levels of hsp90a were at 25 dph. Under the condition of 9°C, regressed oocyte were observed in the ovaries, the oocyte diameter significantly decreased, and the ovaries degenerated 100% after low-temperature stress. The expression levels of hsps in the ovaries were significantly higher than in the control group, while the expression levels in the testes were significantly lower than in the control group. Taken together, hsps may regulate the ovarian degeneration under low-temperature stress. Male fish rapidly completed meiosis and maintained the testes in the prophase of meiosis to resist the low-temperature stress.

Unraveling the causation of flatulence on silver pomfret after starvation aquaculture involved in intestinal microbiota structure, enzyme, and histology

During periods of starvation aquaculture, silver pomfret often suffer from flatulence and lateral flapping, which prevents them from refeeding and dying. Despite existing research on this phenomenon, the understanding of the associated changes in the intestine remains limited. This study aimed to investigate flatulence in silver pomfret during starvation. We conducted a comprehensive analysis of the enzymatic activity, histology, and microbial communities in the gut. Through the examination of 28 samples, we found that the trigger for flatulence under starvation does not appear to be enzyme activity but rather gut microbes. During periods of food deprivation, the fish often ingest air bubbles, leading to an increased proportion of aerobic bacteria. We observed a notable shift in the β - diversity of the intestinal microbial community in flatulent fish, accompanied by a significant decrease in network stability. A marked enrichment in functional microbes was noted, which contributed to increased activities related to CO2 production. In conclusion, this study provides novel insights into the mechanism of flatulence in silver pomfret during starvation stress, highlighting the role of microbial composition. These findings have significant implications for improving aquaculture practices by addressing microbial management.

Immune Response of Silver Pomfret (Pampus argenteus) CC Chemokine Ligand Gene Family to Photobacterium damselae Subsp. Damselae and Nocardia seriolae Infections.

Chemokines play a crucial role in immune responses by facilitating the migration of cells expressing corresponding chemokine receptors along concentration gradients. Photobacterium damselae subsp. Damselae (PDD) and Nocardia seriolae (NS) are known to induce substantial mortality in silver pomfret populations, yet there exists a dearth of research regarding the immune response of CCLs in PDD- or NS-infected silver pomfret. In our investigation, we identified 10 PaCCLs, which include one fish-specific CCL (PaCCL44). Phylogenetic analysis revealed considerable diversity in CCL types and copy numbers among various teleost fishes. Notably, silver pomfret lacks specific CCL genes, with most PaCCLs exhibiting heightened expression levels in immune-related organs such as the spleen and kidney, and some being expressed in mucosal immune-related organs like the skin and gills. Transcriptome analysis conducted on silver pomfret infected with NS and PDD elucidated that the expression changes of PaCCLs primarily manifested in the spleen during the initial stages of NS infection, shifting to the kidney in later stages. Conversely, the expression changes of PaCCLs following PDD infection predominantly occurred in the kidney. Invitro studies using silver pomfret spleen cell lines demonstrated an early peak in PaCCLs expression during infection, followed by gradual decline with NS treatment and rapid diminishment with PDD treatment. These findings suggest that PaCCLs primarily support the innate immunity of silver pomfret, potentially exhibiting chemotactic effects in the early infection stages, such as the synergistic action of PaCCL4 and PaCCL25, and later serving as direct antibacterial agents. NS invasion is characterised by a chronic infection affecting multiple organs, whereas PDD primarily inflicts severe damage to the kidney. PaCCL19a and PaCCL19b are specific to PDD, and their expression levels may decrease in the later stages of infection due to PDD immune escape. These data offer initial insights into understanding the mechanism underlying the innate immune response of the CCL gene family in silver pomfret and provide theoretical underpinnings for fish culture practices.

Two high quality chromosome-scale genome assemblies of female and male silver pomfret (Pampus argenteus)

Pampus argenteus is a highly commercial marine fish whose population is declining sharply. Here, we generated a female P. argenteus genome, spanning 536.33 Mb with contig N50 of 1.79 Mb; 24070 genes (99.50% of 24,182) were functionally annotated. To improve quality of it, we assembled a 553.79 Mb genome of male fish with contig N50 of 24.75 Mb through HiFi and ultra-long ONT sequence technologies; 550.82 Mb were anchored onto 24 gap-free chromosomes; 22,892 genes (98.1% of 23,346) were functionally annotated; the QV value was 51.55 with 98.9% of BUSCO and 99.39% coverage of Illumina reads. Finally, we compared this genome with previous published one, revealing 37,301 SVs. 52.82 Mb and 18.05 Mb SDs were characterized in our and published assemblies, respectively, and 48.96 Mb PURs were constructed. Thus, this genome assembly exhibits excellent completeness, continuity and accuracy comparing to the published one, which can be current preferred reference genome. Overall, these works help aquaculture and wild resources recovery of P. argenteus and provide a valuable genetic resource for study.

Effects of supplemental medusa (Rhopilema esculentum) on intestinal microbiota and metabolites in silver pomfret (Pampus argenteus).

Pampus argenteus demonstrates a preference for Rhopilema esculentum as prey, yet the ramifications of consuming supplemental medusa on fish microbiota and metabolism remain elusive. To elucidate these effects, 300 juvenile fish were divided into two groups: control group (C, given commercial food only) and supplemental medusa (SM) group (given supplemental medusa + commercial feed). After 15 days, fish in the SM group exhibited a significant increase in fatness, the amylase activity in the intestine significantly increased, and the intestinal microvilli were arranged more neatly. The comprehensive approach involving 16S rRNA amplicon sequencing and metabolomics was employed, leading to the identification of five genera within the SM group, namely Lactococcus, Cohaesibacter, Maritalea, Sulfitobacter, and Carnobacterium. Functional prediction analysis of the microbiota indicated that the consumption of supplemental medusa facilitated processes such as glycolysis/gluconeogenesis and amino acid absorption. Metabolomics analysis revealed significant enrichment of 85 differential metabolites, most of them belonging to fatty acids and conjugates. These differential metabolites primarily participated in processes such as amino acid metabolism, fatty acid synthesis, and disease. Notably, the consumption of medusa resulted in a significant reduction in nine lysophospholipids associated with cardiovascular disease and inflammation. Pearson's correlation coefficient analysis revealed associations between specific microorganisms and metabolites, indicating that Cobetia, Weissella, and Macrococcus exhibited an increased abundance in the SM group, positively correlating with apocynin, 12-Hete, and delta 9-THC-d3. The indicator bacteria Psychrobacter reduced in the SM group, exhibiting a negative correlation with cystathionine (a compound involved in glutathione synthesis). Overall, the supplementation of medusa may confer a beneficial effect on the immunity of the fish. This study contributes to the theoretical framework for fish feed development.

Whether the summer fishing moratorium can improve the status of fisheries resources in the yellow sea and Bohai Sea

The China government has introduced many strategies in fisheries management of the Yellow Sea and the Bohai Sea, the most stringent of which is the summer fishing moratorium. Whether the summer fishing moratorium can restore fishery resources has always been a concern. In this study, we selected eight representative commercial fish species the Yellow Sea and Bohai Sea, including Pampus argenteus, Trichiurus lepturus, Scomberomorus niphonius, Ilisha elongata, Thamnaconus modestus, Scomber japonicus, Engraulis japonicus and Larimichthys polyactis, and used the JABBA method to study their historical exploited dynamics and current stock status. We evaluated the effectiveness of the summer fishing moratorium based on the increments of biomass and catch after its implementation and adjustments. P. argenteus and S. niphonius stocks were in the healthy status in 2022, the other six fisheries stocks were overexploited. The summer fishing moratorium had a strong conservation effect, especially after the first implementation in 1995, with the biomass of six fish species increased and the catch of seven species increased, and the total average biomass and catch increments were 21.22 % and 89.72 %. This positive effect was also reflected after the first adjustment in 2003. Although the moratorium duration was continuously extended after the second and third adjustment, the conservation effect was offset by the flooding of fishing efforts immediately after the moratorium. For the six overexploited stocks, we suggest that the allowable catch of E. japonicus, T. lepturus, L. polyactis, S. japonicus, I. elongata and T. modestus is at most 527.91 kt, 147.51 kt, 93.43 kt, 81.51 kt, 1.25 kt and 4.95 kt in the Yellow Sea and Bohai Sea, respectively.

Comparative analysis of the microbiota succession and flavor formation in spontaneously fermented fish sauces made with silvery pomfret (Pampus argenteus) and little yellow croaker (Larimichthys polyactis)

Our study delved into exploring the bacterial profiles and volatile compounds during the fermentation of two distinct fish sauces, i.e., Larimichthys polyactis (LP) and Pampus argenteus (PA), and a co-occurrence network was employed to investigate the underlying relationship between flavor and microorganisms. The pH (6.97–5.66) remarkably declined while the total volatile basic nitrogen (TVB-N, 92.36–116.55 mg/100 mL) and amino acid nitrogen (AAN, 104.49–638.68 mg/100 mL) contents gradually rose with the fermentation of LP and PA samples. Bacterial community analysis revealed that Psychrobacter was the dominant genus before LP fermentation, and its relative abundance was gradually occupied by Staphylococcus after 7M. The most dominant genus before PA fermentation was Photobacterium, while Virgibacillus emerged as the predominant genera of PA samples after 7M. Seven main volatile compounds made salient contributions (VIP ≥1.0, ROAV ≥1.0) to the flavor of LP- and PA-fermented samples, respectively. Among them, three typical genera (Tetragenococcus, Streptococcus and Staphylococcus) and four specific genera (Tetragenococcus, Psychrobacter, Vagococcus and Lactobacillus) were the core microorganisms contributing to flavor compounds in LP and PA samples, respectively. Therefore, acquiring insight into the microbes responsible for key flavors in multi-variety fermented fish sauces could provide essential indicators for optimizing commercial fermentation processes.

Identification, molecular profiling and immune functions of cystatin M in silver pomfret (Pampus argenteus)

Cystatins play an important role in various physiological and pathological processes of organisms, including regulating protein metabolism, antigen processing, inflammatory response, nutritional disorders, and controlling enzyme activity. However, research on immunity functions of fish cystatin M is limited. In this study, Pampus argenteus cystatin M (Pacystatin M) was identified and analyzed. Its amino acid sequence was highly conserved in teleosts, and included the conserved cystatin cysteine protease inhibitor motifs. Pacystatin M was highly expressed in the gill, spleen, and intestine, whereas the expression levels of liver and kidney were lower. Furthermore, Nocardia seriolae infection up-regulated the expression of Pacystatin M in the kidney, spleen and liver, with particularly significant expression observed in the liver on day 15 post-infection. Functional analysis indicated that the recombinant Pacystatin M showed increasing inhibitory activity against papain within a certain concentration range, suggesting that the inhibition was likely competitive. Additionally, Pacystatin M demonstrated the ability to inhibit bacterial growth and high thermal stability. These results suggested that Pacystatin M might be involved in the immune response to microbial invasion and provided new reference addressing disease issues in the large-scale farming of silver pomfret.

Variations in methylmercury contamination levels and associated health risks in different fish species across three coastal bays in China

The growing atmospheric mercury (Hg) emissions in China have raised ongoing concerns regarding contamination in marine fish. To better understand the pollution patterns and associated risks, we examined methylmercury (MeHg) content in demersal and pelagic fish from four commonly found families in three geographically distinct bays along the Chinese coast. We identified significant spatial variations in MeHg levels within the same fish family across regions. Specifically, fish collected from the Beibu Gulf in the South China Sea consistently exhibited significantly higher MeHg levels compared to those from the Laizhou Bay in the Northeast and/or Haizhou Bay in the East of China. In contrast, MeHg levels in fish collected from Haizhou Bay consistently remained the lowest. Within each region, we observed significantly higher MeHg concentrations in demersal species compared to pelagic species. This trend was particularly evident in fish species including bartail flathead (Platycephalus indicus), small-scale tongue sole (Cynoglossus microlepis) and greater lizardfish (Saurida tumbil) from the Beibu Gulf (0.50, 0.21, and 0.18 mg/kg dw, respectively), as well as bartail flathead and slender lizardfish (Saurida elongata) from Laizhou Bay (0.09 and 0.12 mg/kg dw, respectively). By comparison, MeHg content in silver pomfret (Pampus argenteus) from all three regions consistently remained relatively lower than in other species. Using target hazardous quotient (THQ) calculations, we estimated potential health risks in local populations associated with the consumption of the studied fish species. Our results showed a lack of apparent health risks to local residents, as all THQ values obtained from the three regions fell within the safe limits (0.02–0.94). However, it remains important to conduct additional assessments and spatiotemporal monitoring that encompass a broader range of species and regions.

Dietary effects of vitamin C on antioxidant capacity, intestinal microbiota and the resistance of pathogenic bacteria in cultured Silver pomfret (Pampus argenteus).

As most teleosts are unable to synthesize vitamin C, supplemental diets containing vitamin C diets play a crucial role in fish health. The aim of this study was to investigate the effect of dietary vitamin C on the intestinal enzyme activity and intestinal microbiota of silver pomfre (Pampus argenteus). Four experimental diets were supplemented with basic diets containing 300 mg of vitamin C/kg (group tjl3), 600 mg of vitamin C/kg (group tjl6), and 1200 mg of vitamin C/kg (group tjl12), as well as vitamin C-free supplemental basic diet (group tjl0), respectively. The four diets were fed to juvenile P. argenteus (average initial weight: 4.68 ± 0.93 g) for 6 weeks. The results showed that the activity of SOD (superoxide dismutase) and CAT (catalase) increased significantly while that of MDA (malondialdehyde) decreased significantly in group tjl3 compared to vitamin group tjl0. At the genus level, groups tjl0, tjl6, and tjl12 contained the same dominant microbial community, Stenotrophomonas, Photobacterium, and Vibrio, whereas group tjl3 was dominated by Stenotrophomonas, Delftia, and Bacteroides. Among the fish fed with a basic diet containing 300 mg of vitamin C/kg, the intestines exhibited a notable abundance of probiotic bacteria, including lactic acid bacteria (Lactobacillus) and Bacillus. The abundance of Aeromonas in groups tjl3 and tjl6 was lower than that of the vitamin C-free supplemental basic diet group, whereas Aeromonas was not detected in group tjl12. In addition, a causative agent of the disease outbreak in cultured P. argenteus, Photobacterium damselae subsp. Damselae (PDD) was the dominant microbiota community in groups tjl0, tjl6 and tjl12, whereas the abundance of PDD in group tjl3 was the lowest among the diets. Taken together, the diets supplied with vitamin C could influence the composition microbial community of P. argenteus. The low level of vitamin C (300 mg of vitamin C/kg per basic diet) supplementation could not only improve the antioxidant capacity but also resist the invasion of pathogenic bacteria.

Organophosphate esters and their metabolites in silver pomfret (Pampus argenteus) of the Vietnamese coastal areas: Spatial-temporal distribution and exposure risk

A large number of studies on organophosphate esters (tri-OPEs) in marine organisms have not assessed the simultaneous occurrence of tri-OPEs and their metabolites (di-OPEs) in these species. This research investigated the concentration and geographical distribution of 15 tri-OPEs and 7 di-OPEs in 172 samples of Pampus argenteus that were collected annually from 2021 to 2023 at three distinct locations along the Vietnamese coast. As a result, tri-OPEs and di-OPEs were detected in numerous fish samples, indicating their widespread spatial and temporal occurrence in marine fish and pointing out the importance of monitoring their levels. The tri-OPEs and di-OPEs ranged within 2.1–38.9 ng g−1 dry weight (dw) and 3.2–263.4 ng g−1 dw, respectively. The mean concentrations of tri-OPEs ranged from 0.4 (TIPrP) to 5.4 ng g−1 dw (TBOEP), with TBOEP and TEHP having the highest mean values. In addition, the profiles of tri-OPEs in fish exhibited a descending order: Σalkyl OPEs > ΣCl-alkyl OPEs > Σaryl OPEs. The di-OPEs, namely BEHP and DMP, had the highest mean levels, measuring 33.4 ng g−1 dw and 23.8 ng g−1 dw, respectively. Furthermore, there have been significant findings of strong positive correlations between di-OPEs and tri-OPE pairs (p < 0.05). It is worth noting that there is a noticeable difference in the composition of tri-OPEs between the North and other regions. Despite these findings, the presence of OPE-contaminated fish did not pose any health risks to Vietnam's coastal population.

Identification of major histocompatibility complex II gene in Pampus argenteus and the expression pattern in Pampus argenteus kidney cell line under the pathogen stress

Major histocompatibility complex II (MHCII) is a critical immune molecule that plays an essential role in combating external pathogens in fish. To investigate MHCII in the economically significant fish species, silver pomfret, we firstly identified three PaMHCIIs, including one PaMHCIIa and two PaMHCIIbs, all closely related to Trachinotus ovatus MHCII. Ig superfamily, C1-set and IGc1 domain were identified in PaMHCIIs, with MHCII alpha and MHCII beta domians found in PaMHCIIa and PaMHCIIbs, respectively. To further elucidate their immune function, we analyzed three transcriptomes from fish infected with a primary pathogenic bacterium, discovering that MHCII was highly enriched in Antigen processing and presentation (map04612). To explore the regulatory relationships of these differentially expressed genes (DEGs) in vitro, we established a Pampus argenteus kidney cell line (PaK) and construct a main pathogenic bacteria-Photobacterium damselae subsp. Damselae (PDD) infection PaK model according to the change of cell viability. In this model, the TUNEL signal did not exhibit significant changes at 6 h but increased gradually; compared to 0 h, tested genes were up-regulated at 6 h; All genes, except PaMHCIIs, GILT and CTSB, were up-regulated at 12 h. At 18 h, TCR was up-regulated while Ii and CTSL were significantly down-regulated. By 24 h, TCR, Ii and CTSL were down-regulated. These results suggest that the MHCII pathway is activated during the early stages of infection, but PDD may suppress it later through immune evasion mechanisms. This data enhances our understanding of the origin, evolution, and function of MHCII and provides guidance for disease control in silver pomfret aquaculture.

Identification and functional characterization of galectin-3 in silver pomfret (Pampus argenteus)

Galectin-3, as a unique member of the galectin family, exhibits a significant role in both extracellular and intracellular environments. In this study, the silver pomfret galectin-3 gene (SpGal-3) was cloned and functionally characterized. The open reading frame of SpGal-3 was found to be 843 base pairs in length, encoding a protein of 280 amino acids. Phylogenetic tree analysis indicated that SpGal-3 was highly conserved in fish species. The mRNA of SpGal-3 was expressed at various levels in all tested tissues, with the gill exhibiting the highest expression levels. Furthermore, infection with Photobacterium damselae subsp. damselae significantly changed the mRNA expression of SpGal-3 in liver and head kidney tissues. Subcellular localization analysis suggested that SpGal-3 was expressed in both the nucleus and cytoplasm. Purified recombinant protein of SpGal-3, designated as rSpGal-3, showed binding ability to two classic pathogen-associated molecular patterns (peptidoglycan and lipopolysaccharide) and two sugars (D-mannose and D-galactose), with the highest affinity toward lipopolysaccharide. Additionally, rSpGal-3 demonstrated the capability to interact with various bacterial species. Taken together, our findings underscore the critical role of SpGal-3 as a key pattern recognition receptor in the immune response of the silver pomfret.

Sexual differentiation and juvenile hermaphroditism in silver pomfrets: Direction, process, and dietary factors

Silver pomfrets (Pampus argenteus) are one of the high market price among marine economic fishes, with female individuals exhibiting higher growth rates and larger body sizes. However, the process of sexual differentiation in this species remained unclear. In this study, the histological evidence of gonadal development processes before, during and after sexual differentiation was studied in silver pomfrets, revealing a duration of juvenile hermaphroditism during sexual differentiation. The individuals were further categorized into three distinct types (type A, B and C) based on the proportion of PN follicles and the presence of apoptotic bodies in their gonads. The process of sexual differentiation in individuals administered with E2 or MT revealed that individuals categorized into type A pattern exhibit a female-biased tendency and subsequently develop ovarian follicles, whereas individuals of types B and C displayed a male-biased pattern, leading to apoptosis of oocytes and contributing to the formation of testicular lobules. Additionally, the emergence of sexual size dimorphism between male and female silver pomfrets was observed prior to sexual differentiation. Our further evidence had revealed a significant increase in lipid content within the female-biased gonad and serum, as compared to that found in the male-biased samples during sexual differentiation. Moreover, we have found that lipid supply can influence the process of sexual differentiation, with fish oil leading to feminization when compared to soybean oil. In summary, the present study investigated the process of sexual differentiation in silver pomfret and provided support for the hypothesis that manipulating lipid supply can influence the sexual differentiation process and regulate the sex ratio in aquaculture.

Length–weight Relationship and Condition Factor of Silver Pomfret (Pampus argenteus), Damanganga Estuary, Daman

A study was conducted on the length-weight relationship and condition factor of the commercially important fish, Silver Pomfret (Pampus argenteus), in the Damanganga estuary in Daman. Fish samples were collected from January 2021 to March 2021, with a total of 330 randomly sampled fish collected from fishermen. The average total length was 23.309±0.775 cm and the average total weight was 259.606±20.144 grams measured using standard methods. The 'b' value of Pampus argenteus showed a negative allometric (b&lt;3.0) growth pattern, with the total length being positively correlated with the total weight of the fish (r²=0.829). The growth pattern was negative allometric while the Fulton condition factor (2.03±0.114) indicated good condition. Therefore, further studies on the length-weight relationship should focus on the sustainable management of the fisheries.

Simulated cold spell: Changes of lipid metabolism on silver pomfret during cooling and rewarming

In recent decades, frequent extreme cold spells have led to fluctuations in water temperature. As poikilotherm, fish adapt to the environmental temperature through a series of physiological and metabolic regulation. Silver pomfret (Pampus argenteus) is an economical marine fish, a potential candidate for aquaculture. To investigate the impact of cold stress and subsequent rewarming on the energy metabolism of silver pomfret, we simulated an extreme cold spell by gradually lowering water temperature from 18 °C to 6 °C, followed by a gradual rise to 12 °C. The findings revealed notable trends: as the water temperature dropped to 12 °C, there was a significant increase in fatty acid content. However, upon reaching 6 °C, the condition factor (CF) decreased, accompanied by a reduction in liver mass. During the rewarming phase, severe tissue damage was observed in both muscle and liver tissues, alongside elevated AST and ALT activity. Besides, silver pomfret consumed stored fatty acids, CF, hepatosomatic index and n-3/n-6 fatty acid ratio were higher than other groups once the water temperature returned to 12 °C. Further transcriptome sequencing of the liver revealed significant enrichment in numerous metabolism-related pathways through KEGG and GO analyses. Ten differentially expressed genes (DEGs), encoding pivotal enzymes in lipid metabolism, were identified from pathways such as the PPAR signaling pathway and fatty acid degradation. Based on these results, it was hypothesized that silver pomfret shields against injury by modulating fatty acid composition. This hypothesis found validation in P. argenteus liver cells, where acsl1, cpt1 and cpt2 were identified to facilitate lipid activation and transportation. Knocking down acsl1 impacted the utilization of lipid droplets, further affirming this mechanism. This study sheds light on the adaptive strategies of economically significant fish species in confronting extreme cold spells, providing valuable insights for future reference.

Tenascin can inhibit apoptosis induced by copper in silver pomfret (Pampus argenteus)

Silver pomfret, an economically important fish species, encounters significant challenges posed by copper pollution in wild and culturing environment. High level of copper has the potential to accumulate in aquatic organisms over prolonged exposure periods. The extracellular matrix, which is highly susceptible to copper, encompasses various proteins, among which tenascin (TN) might play a crucial role in potentially regulating copper-induced apoptosis. To investigate this hypothesis in fish, we initially identified six TN family members in silver pomfret, namely TNCa, TNCb, TNR, TNXB, TNXBa and TNN. Phylogenetic analysis showed four gene subfamilies, namely TNC, TNR, TNN, and TNX, through comparative analysis with TNs from seven other teleost fish species. Subsequently, we analyzed transcriptome of silver pomfret under copper stress and found differential expression of TN family genes under varying levels of copper stress, particularly TNCa. KEGG enrichment analysis demonstrated a significant enrichment of TN downstream pathway, specifically the Pi3K-AKT signaling pathway. RT-qPCR results indicated up-regulation of TNs and apoptosis inhibition-related genes and down-regulation of apoptosis promotion-related genes within this pathway. Hence, we speculated that TN inhibits copper-induced apoptosis by modulating this particular pathway. To further validate this hypothesis, we established a copper stress cell model using a silver pomfret kidney cell line (PaK) and utilized siRNA to knock down TNCa expression within this cellular model. Comparing RNAi-Cu group to NC-control group, we observed significantly reduced cell viability and intensified apoptosis signals in the former. Additionally, RNAi-Cu group displayed down-regulation of apoptosis inhibition-related genes and up-regulation of apoptosis-related genes in Pi3K-AKT signaling pathway compared to NC-Cu group. These findings indicated that TN might be able to inhibit copper-induced apoptosis through Pi3K-AKT signaling pathway. Ultimately, this study offers foundational knowledge for exploring heavy metal toxicity effect on fishes and some references for utilization of copper in parasite control.

Identification and characterization of STAT family in silver pomfret (Pampus argenteus) involved in different exogenous stresses

Members of the Signal Transducer and Activator of Transcription (STAT) family function pivotally as transcriptional activators integral to the modulation of inflammatory responses. The aquaculture of silver pomfret is frequently compromised by the imposition of exogenous stressors, which include thermal fluctuations, notably low-temperatures, diminished oxygen levels, and the onslaught of bacterial pathogens. Notwithstanding the critical impact of these stressors, the scientific literature presents a notable gap in our understanding of the STAT pathway's role in the silver pomfret's adaptive response mechanisms. To address this lacuna, we identified stat genes in the silver pomfret—denominated as Pastat1, Pastat2, Pastat3, Pastat4, and Pastat5—through a thorough and systematic bioinformatics analysis. Further scrutiny of the gene configurations and constituent motifs has elucidated that STAT proteins possess analogous structural frameworks and exhibit significant evolutionary preservation. Subsequently, the expression patterns of five stat genes were verified by RT-qPCR in twelve different tissues and four growth periods in healthy fish, showing that the expression of Pastat genes was temporally and spatially specific, with most of the stat genes expressed at higher levels in the spleen, following muscle, gill, and liver. Transcriptomic analysis of exposure to exogenous stressors, specifically formaldehyde and low-temperature conditions, elucidated that Pastat1 and Pastat2 genes exhibited a heightened sensitivity to these environmental challenges. RT-qPCR assays demonstrated a marked alteration in the expression profiles of jak1 and Pastat gene suites in PaS upon prolonged bacterial infection subsequent to these exogenous insults. Moreover, the gene expression of the downstream effectors involved in innate immunity and apoptosis displayed marked deviations. This study additionally elucidated the Pastat gene family's role in modulating the innate immune response and apoptotic regulation within the silver pomfret during exogenous stressors and subsequent pathogenic incursions.

Complement C1q is involved in the activation of membrane attack complexes, regulation of bacterial infectious inflammation, and apoptosis through overexpression in primary cells of silver pomfret (Pampus argenteus) in vitro

The complement system is pivotal in innate immune defense, with Complement 1qb (C1qb) playing a key role in recognizing immune complexes and initiating the classical pathway. In this research, we cloned the full-length cDNA of silver pomfret (Pampus argenteus) c1qb and demonstrated its role in mediating defense responses against Nocardia seriolae (N. seriolae) infection, which notably causes significant economic losses in the aquaculture industry. Our investigation revealed that N. seriolae infection led to tissue damage in fish bodies, as observed in tissue sections. Subsequent analysis of differential genes (DEGs) in the transcriptome highlighted genes linked to apoptosis and inflammation. Through experiments involving overexpression and interference of c1qb in vitro, we confirmed that c1qb could suppress N. seriolae-induced apoptosis and inflammation. Moreover, overexpression of c1qb hindered N. seriolae invasion, and the purified and replicated C1qb protein displayed antimicrobial properties. Additionally, our study unveiled that overexpression of c1qb might stimulate the expression of membrane attack complexes (MAC), potentially enhancing opsonization and antibacterial effects. In conclusion, our findings offer valuable insights into the immune antibacterial mechanisms of c1qb and contribute to the development of strategies for controlling N. seriolae.

The distinctive morphology of caudal neurosecretory system and its impact on Pampus argenteus throughout the breeding season

The caudal neurosecretory system (CNSS) of teleost is intricately linked to reproduction. This study sought to explore the association between the CNSS and the reproductive cycle of Pampus argenteus. Utilizing microscopy and transmission electron microscopy, we observed the morphological alterations within the CNSS. Furthermore, we quantified the levels of urotensin-I (U-I), urotensin-II (U-II), cortisol, and corticotropin-releasing hormone (CRH) throughout the reproductive process. Findings revealed that Dahlgren cells, distributed along the spinal cord adjacent to the terminal 6 vertebrae of the silver pomfret’s tail, were primarily concentrated within the final 3 vertebrae. The neurohypophysis was characterized by an elongated oval form when viewed laterally and an almost spherical configuration in ventral perspective. Post-breeding season, the average diameters of Type I and Type II Dahlgren cells decreased by 21.8% and 15.44%, respectively (P &amp;lt; 0.05), accompanied by a reduction in neurosecretory granules to merely 60% of their initial pre-reproductive state (P &amp;lt; 0.05). Variations in the serum and gonadal concentrations of U-I, U-II, cortisol, and CRH indicated a significant correlation with gonadal maturation. In summary, the CNSS plays a crucial role in gonadal development, directly or indirectly influencing and modulating the reproductive activities of P. argenteus.