Search Results (338)

Silver nanoparticle (AgNP)-based products have been increasingly applied in aquaculture due to their antimicrobial properties and capacity to modulate host immunity. This study investigated the biological activities of synthesized silver nanowires (AgNWs), with particular emphasis on their anti-Vibrio efficacy and immunomodulatory effects, to evaluate their potential application in shrimp aquaculture. Antibacterial activity was assessed using nonlinear regression analysis to determine minimum inhibitory concentrations (MICs) against three major Vibrio pathogens, while cytotoxicity and immune responses were evaluated using white shrimp hemocytes through cell viability assays and in vitro gene expression analysis, respectively. AgNWs exhibited antibacterial effects on Vibrio parahaemolyticus, Vibrio alginolyticus, and Vibrio harveyi, with MIC values of 873.7, 58.78, and 672.1 μg/mL, respectively. Hemocyte viability remained above 90% at AgNW concentrations of up to 1000 mg/L, indicating good biocompatibility. AgNWs significantly upregulated immune-related lipopolysaccharide and β-1,3-glucan-binding protein (LGBP) and Toll gene expression at specific concentrations, indicating immunostimulation. These results suggest that AgNWs possess antibacterial activity and immunomodulatory potential with low cytotoxicity, supporting their promise as a novel functional agent for shrimp disease management. Full article

Molting determines survival and growth in cultured crustaceans, yet its specific regulatory mechanisms remain complex. This study integrated transcriptomics and microbiome analyses to elucidate molting regulation in crayfish (Procambarus clarkii). Crayfish were injected with 20-hydroxyecdysone (20E) at 20 and 250 ng/g to simulate early premolt and middle premolt, respectively. The comprehensive upregulation of nuclear receptor family genes confirmed the reliability of the in vivo 20E injection simulation. The results showed that 20 ng/g 20E stimulation induced 13,253 unique DEGs in the epidermis, mainly enriched in protein catabolism (promoting proteolysis to degrade the old exoskeleton), and induced 137 unique DEGs in hemocytes, mainly linked to ribosomal biosynthesis, while the 250 ng/g group showed 2395 unique DEGs in the epidermis, enriched in metabolic processes and biosynthetic processes (supporting the biosynthesis of the new stratum corneum), and 99 unique DEGs in hemocytes enriched in mitochondrial pathways, concomitantly enhancing energy metabolism and antioxidant defense capabilities. Notably, 20E upregulation potentially leads to the dysbiosis of pathogens, specifically Escherichia-Shigella and Vibrio. This study elucidates key biological events in the early and middle premolt of crayfish, clarifies tissue-specific regulatory mechanisms during premolt, and provides molecular-level insights into the growth regulatory network of crustaceans. Full article

Insect hemocytic cell lines offer substantial advantages over primary, in vivo hemocyte cultures, fundamentally transforming experimental approaches in cellular immunology and related fields. Selected Malacosoma disstria cell lines were characterized for optimal growth temperatures, morphogenesis, blebbing, extracellular enzyme profiles, and their interactions with material (polystyrene) and microbial (Bacillus subtilis) surfaces. The adhesive hemocyte lines UA-Md221 and Md108 showed optimal growth at 28 °C, whereas UA-Md203 and Md66 grew best at 21 °C, with Md66 tolerating 21–28 °C. Md108 demonstrated a broader temperature tolerance than other adherent cultures. Both Md108 and UA-Md221 adhered to polystyrene within 24 h post-subculturing, although protease-induced morphological changes in modified Grace’s medium continued through 48 h and 72 h, respectively. Culture quality was monitored by assessing the release of multiple enzymes, including alkaline and acid phosphatases, esterases and lipases, aminopeptidases, proteases, glycosidases, and hydrolases from the cell lines at 50% confluency in modified Grace’s medium. Fetal bovine serum showed elevated esterase lipase (C8) and phosphoamidase activities when diluted in Grace’s medium and phosphate buffered saline (PBS). Exposure to dead B. subtilis suspended in PBS induced quantitative and qualitative alterations in the enzyme secretion profiles of Md66 and Md108 cultures. We conclude that semi-quantitative assessments of hemocytic cell lines can provide valuable insights for the time window of each enzyme release, revealing immune and metabolic signaling patterns. Full article

The bactericidal permeability-increasing protein (BPI) and lipopolysaccharide binding protein (LBP) are fundamental to innate immunity. However, their functional diversity and evolutionary conservation in ecologically crucial invertebrates, such as oysters, remain largely understudied. In this study, we identify and characterize a novel homolog of BPI/LBP, designated as ChBPI/LBP in the Hong Kong oyster (Crassostrea hongkongensis). Through structural and phylogenetic analysis, we identify ChBPI/LBP as a distinct member of the BPI protein family, with a high isoelectric point (pI of 9.26), indicating potent cationic BPI-like bactericidal function. We found that ChBPI/LBP is constitutively highly expressed at mucosal sites such as the gills and is rapidly upregulated in hemocytes following a challenge with Aeromonas hydrophila. Recombinant ChBPI/LBP demonstrated potent and specific bactericidal activity against Gram-negative pathogens. These findings suggest that ChBPI/LBP is an important antimicrobial peptide (AMP) effector in the oyster’s immune response. This work provides novel perspectives on the evolutionary mechanisms of innate immunity in bivalves and may have implications for disease management in aquaculture. Full article

Vibriosis, caused by diverse Vibrio species, is among the most devastating bacterial diseases in shrimp aquaculture. Consequently, breeding shrimp for pan-vibrios resistance (PVR) presents a crucial strategy for sustainable shrimp farming. In this work, we performed a GWAS in Litopenaeus vannamei to identify genetic loci underlying resistance to pan-vibrios and validate the identified SNPs. A total of 300 shrimp from nine different regions were subjected to a comprehensive challenge. Selective genotyping of 300 resistant and susceptible individuals was conducted using a specific length amplified fragment sequencing (SLAF-seq) approach. A total of 18,184,608 high-quality SNPs were detected across the whole genome of L. vannamei. Screening identified 283 SNPs located within genes, 26 of which were associated with the PVR trait. These SNPs were subsequently validated in verification group of 80 shrimps, leading to the identification of two genotypes (GG at SNP20 and AA at SNP21) and one genotype combination (GG/AA at SNP20 and SNP21) that were significantly associated with the PVR trait. Notably, these linked SNPs were identified in the intron of LvHEATR1 gene. The highest LvHEATR1 expression was observed in immune-related tissues including hemocytes, the gills, and the hepatopancreas. Furthermore, qPCR results showed that LvHEATR1 expression was significantly higher in the vibrios-resistant (RES) group than in the vibrios-susceptible (SUS) group. This study proposed the PVR concept and provided valuable molecular markers for the genetic improvement of vibrios-resistance in L. vannamei. Full article

Osmotic stress affects ion transport and cell hydration, potentially disrupting redox homeostasis through altered proteostasis and mitochondrial metabolism. However, how immune hemocytes coordinate volume regulation with these stress-linked processes, particularly oxidative stress and antioxidant responses, remains unclear in crustaceans. This study integrated quantitative cytology, RNA sequencing, and network analysis to profile hemocyte volume plasticity in the euryhaline shrimp Penaeus monodon across a salinity gradient. Hemocytes were incubated for 24 h in hypoosmotic, isosmotic, and hyperosmotic media, with significant volume shifts observed while maintaining membrane integrity and morphology. The permeability of solutes (urea and sorbitol) suggested that volume adjustment is coupled with solute transport. Transcriptomic analyses identified key salinity-responsive pathways, including oxidative phosphorylation, MAPK signaling, ribosome biogenesis, and antioxidant defense mechanisms, underscoring the activation of redox-regulatory systems under osmotic stress. Weighted gene co-expression network analysis highlighted ribosomal proteins as central hubs in a salinity-responsive module, with qRT-PCR confirming the co-regulation of these hubs alongside representative osmoregulatory and antioxidant genes (AQP4, Na⁺/K⁺-ATPase, HSP70, CHOP, and antioxidant enzymes). These findings reveal how hemocyte volume dynamics are coupled to redox regulation, providing a mechanistic framework for understanding osmotic stress–redox coupling in crustacean immune cells. Full article

Natural compound-based strategies have gained attention as alternatives to conventional antifungal therapies, particularly in the management of Candida infections affecting the oral cavity, such as denture stomatitis. Our aim was to investigate the antifungal activity of the polyphenol pterostilbene (PTE) on clinical Candida isolates and microcosm biofilms from denture stomatitis, as well as to evaluate its toxicity and therapeutic efficacy in Galleria mellonella. PTE exhibited fungicidal effects against Candida albicans and Candida dubliniensis at 32 µg/mL. Time-kill assays demonstrated complete inhibition of viability for both strains within 8 h of exposure. In addition, PTE exhibited broad-spectrum antimicrobial activity, significantly reducing the counts of streptococci, mutans streptococci, staphylococci, and yeasts within microcosm biofilms. In vivo, PTE showed no signs of toxicity in G. mellonella at concentrations up to 20× MIC. Prophylactic treatment with PTE enhanced larval survival in experimental candidiasis caused by both C. albicans and C. dubliniensis. Moreover, prophylactic treatment decreased the fungal burden of C. albicans in the G. mellonella hemolymph, while the recruitment of hemocytes involved in host defense mechanisms remained unaltered. In summary, PTE demonstrated antimicrobial activity against Candida planktonic cells and complex biofilms associated with denture stomatitis, exhibiting favorable biocompatibility and in vivo antifungal efficacy in G. mellonella model. Full article

Coccomyxa parasitica-like algae pose a growing threat to bivalve aquaculture. In this work, for the first time under controlled conditions, the effect of the green parasitic microalgae of genus Coccomyxa sp. in the Sea of Japan on the immune and antioxidant protection of Mytilus galloprovincialis was studied in two ways of infection—through filtration (with feed) and injection (into an adductor). By day 7, mortality in both experimental groups reached 68%. The phagocytic activity of hemocytes significantly decreased in the feed group, which may be due to the masking of the parasite as a food particle. Despite transcriptional activation of catalase and superoxide dismutase genes in hemocytes upon injection, a decrease in enzyme activity and an increase in lipid peroxidation were observed in the gills, indicating local oxidative stress. Catalase activity in the gills was increased when mussels receive cells as food. DNA damage in hemocytes did not reach statistical significance. After injection, there was a significant decrease in the galectin gene expression. The data obtained confirm that Coccomyxa sp. is an active parasite capable of infecting the Mediterranean mussel and modulating the host’s defense systems. Full article

Traditional shrimp maturation uses high water exchange, conflicting with sustainable farming and biosecurity, although broodstock production systems have been updated by the adoption of closed-cycle production. So, this study evaluated BFT for Penaeus vannamei broodstock maturation, comparing it against a conventional system. The research compared two treatments, BFT and CW, in three replicated tank systems. Each experimental unit was a circular fiberglass tank with 5.63 m³ working volume. BFT tanks involved a 3.12 m² mobile triangular cage for viewing and capturing mated females. Parameters monitored included water quality, reproductive performance and hemato-immunological responses. The BFT system resulted in greater water quality stability, significantly lower water consumption, and lower Total Ammonia Nitrogen (TAN) concentrations, indicating efficient ammonia recycling. Also, reproductive performance and most hemato-immunological parameters did not differ significantly between treatments. Although CW showed slightly higher broodstock survival and sperm viability, BFT males exhibited a significantly higher Total Hemocyte Count (THC). Overall, BFT is suitable for sustainable P. vannamei broodstock maturation, as it promotes stable environmental conditions without compromising reproductive or immunological performance. Further research is recommended, particularly regarding effects of zero-water-exchange on male shrimp and improvements on capture structures. Full article

Hemocytes (insect blood cells) consist of several morphological types and perform a variety of physiological processes, including immune responses. However, we do not know how many cell types are functionally differentiated in hemocytes or how they perform independent physiological processes. To address this fundamental question, we analyzed hemocyte transcripts with a single-cell RNA-sequencing (scRNA-Seq) technique. The hemocytes were collected from larvae of a lepidopteran insect, Spodoptera exigua, in which four different hemocyte types were morphologically recognized. scRNA-Seq discriminated 24 hemocyte clusters based on the transcripts of each cell. The clusters were separated into seven functional groups predicted from the top three highly expressed and annotated genes in each cluster: active protein synthesis (12 clusters), apoptosis (5 clusters), melanization (2 clusters), modulating cell shape (6 clusters), antimicrobial peptide production (9 clusters), calcium homeostasis (8 clusters), and cell repairing (1 cluster). Signal components of Toll/IMD immune pathways were variably expressed among the clusters. Biosynthetic genes associated with oxylipin immune mediators were specifically expressed among the clusters. Immune effectors such as melanization and apoptosis were expressed in specific hemocyte clusters. Specifically expressed genes that discriminate hemocyte types were used to develop fluorescence in situ hybridization (FISH) markers. In addition, five new hemocyte groups, which were not among the four known hemocyte types in the transcript profile, were identified and discriminated with their specific FISH markers. The hemocyte clusters underwent dynamic changes upon immune challenge. A trajectory analysis using the transcriptome suggests at least three different hemocyte differentiation pathways. These results indicate that the hemocytes of S. exigua are functionally highly differentiated and exhibit a dynamic transition in response to environmental changes. Full article

Microplastic pollution is a pressing global concern, yet its immunotoxicological impacts on invertebrates remain poorly understood. The Black Soldier Fly (Hermetia illucens) larva has gained attention for its role in waste management and potential bioremediation, making it essential to evaluate its interactions with microplastics. In this study, fluorescent carboxylate-modified polystyrene microbeads were directly injected into the hemocoel of larvae to bypass gut-associated variables and investigate systemic immune responses. Experimental groups were analyzed at multiple time points (1 h, 6 h, 24 h, 48 h, and 7 days) using histopathology, cytology, and confocal laser scanning microscopy. Results confirmed the persistence and systemic distribution of microplastics in hemolymph and tissues, with hemocytes exhibiting active phagocytosis of particles. Microplastics were retained within tissues for up to seven days, indicating long-term sequestration. Histological observations further highlighted their close association with metabolically active organs such as the fat body and Malpighian tubules, suggesting possible effects on detoxification and metabolism. These findings demonstrate that microplastics elicit measurable immune responses and are subject to cellular uptake and retention in insect larvae. The study provides novel insights into the immunological and histopathological consequences of microplastic contamination in H. illucens larvae, with implications for their safe use in bioconversion and bioremediation applications. Full article

The codling moth Cydia pomonella (L.) represents a substantial threat to the apple tree industry, with its cellular content being agronomically vital as it serves as the final immunological and toxicological barrier of the pest. Key hemocyte types identified in the hemolymph include plasmatocytes, granulocytes, spherulocytes, and oenocytoids. Hemolymph samples were in vitro suspended in various salt buffers (physiological saline, phosphate saline buffer (PBS) and Galleria mellonella anticoagulant buffer) to determine the most suitable one for agricultural monitoring purposes. The pH influenced the total hemocyte counts and the type of cells that adhered to the slides. PBS (pH 6.5) was found to be optimal for such studies due to its high levels of cellular attachment, cell viability, absence of melanization, and cellular degeneration effects. The supplementation of 5% CaCl₂ to PBS did not enhance the functional utility of the buffer. The in vivo bacterial challenge of larval hemolymph with 4 × 10⁸ sp/mL Bacillus subtilis provided complete clearance from the microbial invader within 30 min. Hemocytes released antimicrobial lysozyme as part of their innate immune responses. Hemocytic examination of larvae as an agricultural practice is strongly recommended for baseline insecticide resistance avoidance and predictive efficiency of integrated pest management in the apple farm. Full article

Deep-sea mussels of the genus Bathymodiolus exhibit adaptability to nutrient-poor deep-sea environments by establishing nutritional intracellular symbiosis with chemosynthetic bacteria harbored within the gill epithelial cells. However, this poses a conflict for the innate immune system of the host, which must balance the tolerance of beneficial symbiotic bacteria with the need to eliminate exogenous microbes. This review synthesizes existing knowledge and recent findings on Bathymodiolus japonicus to outline the cellular and molecular mechanisms governing this symbiotic relationship. In the host immune system, hemocytes are responsible for systemic defense, whereas gill cells are involved in local symbiotic acceptance. Central to the establishment of symbiosis is the host’s phagocytic system, which non-selectively engulfs bacteria but selectively retains symbionts. We highlight a series of cellular events in gill cells involving the engulfment, selection, retention and/or digestion of symbionts, and the regulatory mechanism of phagocytosis through mechanistic target of rapamycin complex 1, which connects bacterial nutrient supply with host immune and metabolic responses. This integrated model of symbiosis regulation, which links immunity, metabolism, and symbiosis, provides a fundamental framework for understanding how hosts establish and maintain a stable coexistence with microbes, offering a new perspective on symbiotic strategies in diverse organisms. Full article

Anti-lipopolysaccharide factors (ALFs) are an important molecular category within the antimicrobial peptide family. They play a crucial role in resisting pathogen infections and are of importance in the innate immune system of shrimp. A novel ALF-like gene was identified from L. vannamei in this study. Its expression profile was investigated after WSSV infection. Results demonstrated that the mRNA transcription level of the ALF-like gene was significantly upregulated in hemocytes, hepatopancreas, gills, and intestines of L. vannamei. When the mRNA transcription level of the ALF-like gene was inhibited, the expression levels of key WSSV genes (VP 28 and IE 1) were significantly upregulated, accompanied by a decrease in shrimp survival rate. Meanwhile, the expression of genes involved in the apoptotic pathway (Lv-Caspase 3, Lv-Caspase 8, and Lv-Bcl 2) and antioxidant enzyme pathway (Lv-GST, Lv-CAT, Lv-Prx, Lv-GPX, and Lv-SOD) was also significantly increased. Flow cytometry further revealed that the hemocyte apoptosis rate induced by WSSV infection was reduced when the transcription level of the target gene was inhibited. These results indicate that the Lv-ALF-like gene plays an important regulatory role in the resistance of L. vannamei to WSSV infection, and studying the function of this gene is of great significance for disease prevention and control of shrimp. Full article

The novel hybrid fish BTB, derived from crossing blunt snout bream (Megalobrama amblycephala, BSB) and topmouth culter (Culter alburnus, TC), exhibits markedly hypoxia tolerance in aquaculture. In this study, hypoxic treatment experiments confirmed that, comparing to its original parent BSB, the tolerance to low oxygen of BTB increased by 20.0%. Furthermore, a comparative analysis of the transcriptome and metabolome was performed using gill tissues from BTB exposed to normoxic and hypoxic conditions. Under hypoxic conditions, BTB displayed adaptive modifications in gill lamellae and hemocytes. Transcriptomic profiling identified 789 differentially expressed genes (DEGs), with 298 upregulated and 491 downregulated, enriched in pathways including apoptosis, NK cell-mediated cytotoxicity, MAPK/TNF/Toll-like receptor signaling, and HIF-1/FoXO signaling pathways. Twelve hypoxia-related candidate genes (egln3, im_7150988, znf395a, hif-1an, mknk2b, pck2, ero1a, igfbp-1a, vhl, bpifcl, egln1a, and ccna1) were screened and validated as potential contributors to hypoxia tolerance. Metabolomics analysis revealed a total of 108 differential metabolites (78 upregulated and 30 downregulated), predominantly linked to Arginine and proline metabolism, Ether lipid metabolism, Arachidonic acid metabolism, and Glycerophospholipid metabolism. Association analysis of transcriptomics and metabolomics revealed that the DEGs and DMs were enriched in the pathways of glycerophospholipid metabolism, ether lipid metabolism, arachidonic acid metabolism, and arginine and proline metabolism. In summary, BTB exhibited relatively high hypoxia tolerance, and 12 candidate genes related to hypoxia tolerance were identified. These findings laid a foundation for further investigation into the mechanisms of hypoxia tolerance improvement in hybrid fish. Full article