Search Results (57)

The increasing fragmentation of plastic debris into nanosized particles represents a threat to freshwater ecosystems, yet the biological effects of nanoplastics (NPs) on freshwater invertebrates remain poorly understood. This study investigated tissue distribution, cellular effects and immune responses following acute exposure to polyethylene terephthalate nanoplastics (PET-NPs) in the freshwater gastropod Pomacea canaliculata, a species of high ecological relevance and physiological resilience. Adult snails were injected with PET-NPs at 5 or 10 mg/L and sampled after 24 and 72 h. PET-NPs accumulation in the anterior and posterior kidneys was assessed by fluorescence imaging and tissue morphology was evaluated. Stress- and inflammation-related genes (Pc-Heat Shock Protein (HSP)70, Pc-HSP90 and Pc-Allograft inflammatory factor 1) expression was quantified by RT-qPCR. PET-NPs uptake and phagocytic activity were analyzed in circulating hemocytes in vivo and ex vivo. PET-NPs were accumulated in renal tissues, persisting up to 72 h without histopathological alterations. Gene expression analyses revealed non-linear and dose/time-dependent responses. Hemocytes of different morphologies internalized PET-NPs in a dose-dependent manner and showed intercellular particle transfer. Overall, acute PET-NP exposure determines rapid immune handling and tissue sequestration with limited short-term physiological impact, underscoring the potential involvement of immune processes in NPs fate and highlighting the need for chronic exposure studies. Full article

Pomacea canaliculata, listed among the world’s 100 worst invasive alien species, poses serious threats to rice production and freshwater ecosystems. This review synthesizes current research in physiological ecology, molecular genetics, and invasion ecology to examine its invasion success from a multiscale mechanistic perspective. P. canaliculata exhibits broad environmental adaptability at physiological, molecular, and behavioral levels. These adaptations include seasonal cold tolerance, drought-induced dormancy and post-dormancy recovery, acclimation to both freshwater and brackish environments, and tolerance to a range of pollutants and pesticides, including evidence of toxicant-induced hormesis. The species also shows pronounced phenotypic plasticity in growth, reproduction, and resource utilization. Genomic plasticity, multiple introduction events, and introgressive hybridization with closely related species further enhance its evolutionary potential and dispersal capacity. In addition, P. canaliculata displays behavioral adaptations such as learning and alarm responses. The synergistic interaction of these multilayered adaptive mechanisms underpins the global invasion success of this species. This review also identifies key uncertainties in current research and emphasizes the need for greater integration of multi-omics approaches, long-term monitoring of population dynamics in hybrid zones, and experimental studies addressing the interactive effects of multiple stressors, with the ultimate aim of improving invasion risk prediction and management. Full article

Boule is the ancestral member of the Deleted in Azoospermia (DAZ) family and is pivotal for gametogenesis and male fertility in most animals. However, there is a dearth of information on molluscan boule. Here, we identified a counterpart (Pcbol) from the genome of Pomacea canaliculata, which has emerged as a cosmopolitan alien species and notorious pest that causes devastating damage to aquatic biodiversity, freshwater ecosystems and crop production in invaded ranges. This study aimed to investigate the biological roles of Pcbol in male reproduction and to decipher the molecular mechanisms underpinning its modulation via dsRNA-delivered RNA interference (RNAi). The bioinformatic analysis showed that the Pcbol genomic sequence is 12,934 nt in length, harboring an open reading frame of 294 nt that encodes 97 aa residues, with an RRM domain evolutionarily conserved among molluscan orthologues. Spatiotemporal expression profiling indicated the predominant abundance of Pcbol in adult males and testis tissues. dsPcbol, injected at a dose of 4 μg/per snail for 5 days, yielded optimal silencing at both transcript and translation levels of Pcbol, as revealed by qRT-PCR and Western blotting. Immunofluorescence echoed a pronounced reduction in Pcbol signal intensity following RNAi. In addition to the arrested reproductive gland phenotype, the number of sperm cells substantially dwindled upon dsPcbol treatment relative to the dsGFP control. In biochemical and fecundity assays, Pcbol depletion triggered a significant decrease in Te/SP/Arg content and suppressed the number of deposited eggs and hatchability. Furthermore, spermatogenic genes like CDC25/TSSK1/SPATA17/DDX4/Dmrt2/Sox2/Kelch10/SPO11 displayed considerable downregulation post Pcbol silencing, with molecular docking predicting a strong affinity between CDC25 and Pcbol. These molecular modules may interact with Pcbol to mediate knockdown effects on spermatogenesis dysfunction. Collectively, our findings not only confirmed that boule was indispensable for spermatogenesis and male fertility in a mollusk, but also highlighted the Pcbol-based male sterile technique (MST), which can be incorporated into precision pest management (PPM) strategies for sustainable control of P. canaliculata. Full article

Pomacea canaliculata, as a significant invasive alien species, poses severe threats to agricultural development. Currently, chemical applications demonstrate notable efficacy in controlling this pest. However, metaldehyde exhibits overly singular toxicity towards P. canaliculata; niclosamide sulfate is not a molluscicide; and fentin acetate is a fungicide. Currently, these findings fail to elucidate the physiological and biochemical effects of the compounds after they enter the P. canaliculata’s body. In this study, we evaluated the toxicity of metaldehyde (ME), niclosamide sulfate (NS), and fentin acetate (FA) against P. canaliculata and analyzed the morphological and physiological changes in response to chemical stress. The results indicated that three chemicals exhibited potent molluscicidal activity, especially in the NS treatment group. After 12 h exposure to LC₅₀ concentrations (48 h LC₅₀), the surface area of livers was reduced significantly by 12.1%, 13.9%, and 2.8% compared to the control group, while the kidneys expanded significantly by 6.4%, 3.2%, and 16.7%, respectively. The heart showed marked enlargement by 152.1% and 44.2% under niclosamide sulfate and metaldehyde treatments. The pulmonary sac significantly contracted by 23.6% under niclosamide sulfate stress but expanded by 6.1% under fentin acetate exposure. The stomach enlarged significantly after niclosamide sulfate treatment, whereas it shrank by 2.1% and 5.7% under metaldehyde and fentin acetate treatments, respectively. Metabolomic analysis of liver tissues revealed 553, 99, and 585 differential metabolites compared to the control group, respectively. KEGG pathway enrichment analysis showed that the metabolism pathway, lysine degradation, and bile secretion are likely related to the response to chemical stress in P. canaliculata. Further examination showed a significant decrease in total protein content and the activities of malondialdehyde (MDA), acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT) under chemical stress. These findings enhance our understanding of the targeted mechanisms of molluscicides against P. canaliculata. Metaldehyde may exert neurotoxic effects on the P. canaliculata, while niclosamide sulfate may interfere with its respiratory system. Additionally, both chemicals affect metabolic pathways in the snail’s liver, including lipid metabolism and metabolic pathways associated with energy metabolism. These findings provide valuable insights for designing a novel snail control agent and formulating scientific management strategy. Full article

Pomacea canaliculata, a pervasive invasive gastropod, inflicts significant ecological and economic damage in Chinese rice ecosystems. With the limitations of chemical molluscicides, sustainable biological control solutions are urgently required. This study presents a comprehensive investigation into the biocontrol potential of larvae of the endemic aquatic firefly, Aquatica leii, against Pomacea canaliculata. Through controlled laboratory experiments, we evaluated the feeding preference of larvae when offered a choice between Pomacea canaliculata and a native snail (Cipangopaludina chinensis), and systematically quantified the predatory efficiency (lethal time and consumption amount) across the 3rd to 6th larval instars. Furthermore, the lethal activity of crude extracts from distinct anatomical regions of the larval digestive tract (mouthpart, foregut, midgut, and hindgut) was assayed via injection into Pomacea canaliculata. The larvae accepted Pomacea canaliculata as a viable prey source. Predatory performance varied markedly among instars; 4th-instar larvae exhibited optimal efficacy, characterized by the shortest mean lethal time (7.37 min) and the highest mean consumption (1.23 g). Midgut extract was identified as the principal causative agent of mortality, inducing a 96.7% mortality rate in Pomacea canaliculata, which was significantly superior to the minimal effects observed from other extract types. This points to the midgut secretion as a likely source of potent bioactive compounds responsible for rapid snail lethality, warranting further investigation. responsible for rapid snail lethality. Our results conclusively demonstrate, from both behavioral and physiological vantage points, the feasibility of Aquatica leii larvae as a highly effective native biocontrol agent. This work establishes a critical foundation for future research aimed at the isolation and characterization of the midgut-specific active substances, paving the way for the development of novel, target-selective biogenic molluscicides. Full article

Apple snail infestation poses a persistent threat to rice production in open-field environments, where long-term coexistence with this species is unavoidable. This study presents a drone-based precision control approach that integrates high-resolution micro-topographic mapping with site-specific pesticide application. A lightweight mapping unmanned aerial vehicle was deployed to produce centimeter-level microtopographic data across paddy fields, facilitating the identification of deep-water areas preferred by apple snails. From these elevation-derived water risk patterns, prescription maps were generated to guide downstream management decisions, and agricultural drones equipped for granular application subsequently performed targeted pesticide delivery only in these high-risk areas. Over 2 years of field experiments, the proposed method achieved rice yields comparable to those under conventional management while reducing pesticide use by 44.1–63.0%, with lower estimated crop damage in regions with high apple snail occurrence. Designed with robustness and scalability in mind, the system demonstrated considerable potential for practical implementation in general farming households and broader applications in precision pest management. Full article

Angiostrongylus cantonensis (A. cantonensis) is the primary causative agent of human angiostrongyliasis and is widely distributed in Southeast Asia and China, with increasing reports from the Americas. Achatina fulica (A. fulica), Pomacea canaliculata (P. canaliculata), and slugs constitute established intermediate hosts of A. cantonensis, whereas Camaena hainanensis (C. hainanensis) has been newly reported as a host species in Hainan. A TaqMan quantitative PCR (qPCR) method assay targeting a novel genomic region of A. cantonensis was developed to detect infection in 150 snails collected from Hainan Province, China. The assay was employed to detect the parasite larvae across various snail tissues (lung sac, mucus, and foot), and its performance was compared with conventional lung sac microscopy. Out of the 120 A. fulica examined, 75 tested positive using the qPCR assay, yielding a significantly higher detection rate than lung-sac examination (p < 0.05). Significant differences were also observed in the positivity rates across the three snail tissues (lung sac, mucus, and foot) (p < 0.05), with the lung sac showing the highest rate of infection. Importantly, the detection of A. cantonensis DNA in snail mucus highlights its potential for development as a non-invasive diagnostic sample. Additionally, C. hainanensis was identified as a new host of A. cantonensis in Hainan, suggesting its possible contribution to parasite transmission. The newly developed qPCR assay demonstrated superior sensitivity (reflected by lower Ct values) compared with previously published TaqMan qPCR methods. The established qPCR method provides a sensitive and non-invasive tool for detecting A. cantonensis in snails, and can be applied for monitoring and early warning of parasite prevalence and transmission. Full article

Background: The golden apple snail (Pomacea canaliculata), an invasive species originating from South America, has inflicted considerable agricultural and ecological harm in non-native habitats. While the molluscicide niclosamide is currently effective against P. canaliculata, its prolonged use raises environmental concerns and the risk of resistance development. Results: BAM 15 possesses strong molluscicidal activity against P. canaliculata, with 72 h LC₅₀ values of 0.4564 mg/L for adults (shell height: 20–25 mm), 0.3352 mg/L for subadults (10–15 mm), and 0.1142 mg/L for juveniles (2–3 mm). Metabolomic and proteomic profiling revealed that the altered metabolites and proteins both converged on energy metabolism and oxidative stress. Experimental validation revealed that BAM15 collapsed the mitochondrial membrane potential, drove MDA and H₂O₂ upward while depleting NADPH, boosted CAT, SOD and GPX activities, yet suppressed GR, and ultimately inflicted overt damage in the head-foot tissue of P. canaliculata. Conclusions: Our findings reveal that BAM 15 operates via a three-stage mechanism: (1) it disrupts membrane potential (ΔΨm) and impairs ATP production, severely disturbing energy metabolism; (2) energy deficits stimulate excessive electron transport chain activity, generating reactive oxygen species (ROS) and initiating oxidative stress; (3) persistent metabolic imbalance and oxidative damage culminate in extensive tissue injury. These results identify BAM 15 as a promising candidate for molluscicide development. Full article

Ionotropic receptors (IRs) are a divergent subfamily of ionotropic glutamate receptors (iGluRs) that detect olfactory and environmental cues, influencing behaviors such as foraging and adaptation. To explore the evolution of IRs in relation to feeding ecology, we identified IRs and iGluRs from the genomes of four gastropods with distinct diets: Pomacea canaliculata (9 IRs/18 iGluRs), Bellamya purificata (10/22), Cipangopaludina chinensis (11/23), and Babylonia areolata (22/41). IRs were markedly expanded in B. areolata, suggesting lineage-specific diversification. Phylogenetic analysis grouped IRs and iGluRs into three clades, with IRs clustered with GluD, supporting early functional divergence following gene duplication. In all species, IR25b showed tandem duplication and played a central role in protein–protein interaction (PPI) networks. Most IRs were acidic, whereas IR-A and IR-C subgroups were basic, suggesting functional specialization among subfamilies. Structural analysis showed that IRs share conserved domains and motifs across species. Most IRs experienced purifying selection, while P. canaliculata showed relaxed constraints, suggesting weaker functional limitation. Collinearity analysis identified conserved genes, such as BarIR-A.6 and BarIR-D.1, across species. qPCR confirmed tissue-specific expression of IRs in multiple organs. Together, these results reveal the molecular features and evolutionary patterns of IRs in gastropods, highlighting their potential roles in olfaction and dietary adaptation. Full article

Allograft inflammatory factor-1 (AIF1) is a conserved calcium-binding protein involved in inflammatory and neuro-immune responses and expressed in Pomacea canaliculata (Pc-AIF1) during cephalic tentacle regeneration. Here, we investigated the expression and distribution of Pc-AIF1 in control conditions and during cephalic tentacle regeneration. A transcriptomic analysis of 315 RNA-seq datasets revealed maximal Pc-AIF1 expression in circulating hemocytes and hemocyte-rich tissues. Pc-AIF1 was also highly expressed in neural ganglia. Fluorescence in situ hybridization (FISH) evidenced Pc-AIF1 in circulating hemocytes and in the phagocytic hemocyte aggregates in the posterior kidney. qPCR showed the constitutive expression of Pc-AIF1 in cerebral ganglia. FISH experiments showed Pc-AIF1-positive cells within the cephalic tentacle blastema at 24 h post-amputation (hpa). Even if the amputation left them untouched, both the ipsilateral and contralateral cerebral ganglia increased Pc-AIF1 expression until 48 hpa. Immunocytochemical experiments evidenced positive cells to RCA120 (a microglial marker in mammals) among circulating hemocytes, in the connective tissue surrounding the cerebral ganglia, and within the regenerating tentacles. These findings suggest that Pc-AIF1 is a neuro-immune marker constitutively expressed in hemocyte populations and neural tissues; it is associated with the immediate hemocyte response to wounding and the neuro-immune interplay during the regeneration of sensory organs. Full article

The invertebrate neuropeptide F (NPF) signaling plays versatile roles in diverse biological activities and processes. Still, whether and how it mediates feeding and digestion in Pomacea canaliculate remain gaps in our knowledge. Herein, we first identified and characterized PcNPFR via bioinformatics analysis in P. canaliculate, which is a polyphagous herbivore with a voracious appetite that causes devastating damages to ecosystem functioning and services in colonized ranges. Double stranded RNA (dsRNA)-based RNA interference (RNAi) and exogenous rescue were utilized to decipher and substantiate underlying mechanisms whereby NPFR executed its modulatory functions. Multiple sequence alignment and phylogeny indicated that PcNPFR harbored typical seven transmembrane domains (7 TMD) and belonged to rhodopsin-like GPCRs, with amino acid sequence sharing 27.61–63.75% homology to orthologues. Spatio-temporal expression profiles revealed the lowest abundance of PcNPFR occurred in pleopod tissues and the egg stage, while it peaked in male snails and testes. Quantitative real-time PCR (qRT-PCR) analysis showed that 4 µg dsNPFR and 10⁻⁶ M trNPF (NPFR agonist) were optimal doses to exert silencing and rescue effects, accordingly with sampling time at 3 days post treatments. Moreover, the dsNPFR injection (4 µg) at 1/3/5/7 day/s delivered silencing efficiency of 32.20–74.01%. After 3 days upon dsNPFR knockdown (4 µg), mRNA levels of ILP7/InR/Akt/PI3Kc/PI3K_R were significantly downregulated compared to dsGFP controls, except FOXO substantially upregulated at both transcript and translation levels. In addition, the activities of alpha-amylase, protease and lipase were significantly suppressed, accompanied by decreased leaf area consumption, attenuated feeding behavior and diminished feeding rate. Moreover, expression trends were opposite and proxies were partially or fully restored to baseline levels post exogenous compensation of trNPF, suggesting phenotypes specifically attributable to PcNPFR RNAi but not off-target effects. PcNPFR is implicated in both feeding and digestion by modulating the ISP pathway and digestive enzyme activities. It may serve as a promising molecular target for RNAi-based antifeedants to manage P. canaliculate invasion. Full article

The impact of invasive alien species (IAS) is one of the direct factors causing global biodiversity decline and economic losses, and predicting the potential invasion risks of invasive species is crucial for developing prevention and control strategies. In recent years, an increasing number of studies have shown that invasive species undergo rapid shifts in climate niche in invaded areas. Accurately quantifying the dynamic shifts in the climate niche of invasive species in invaded areas is crucial for developing a more accurate framework for early warning of invasive species risks. Pomacea canaliculata is a freshwater snail found in South America and has become one of the most aggressive aquatic species in the world. Since its introduction to China in 1981, it has rapidly spread and caused multiple serious damages to agriculture, ecology, and public health. Therefore, based on multi-source distribution data of P. canaliculata, this study calculated the climate niche overlap by Schoener’ s D, quantified the niche shifts between the P. canaliculata in native and invaded areas (China) via the COUE scheme (a unified terminology representing niche centroid shift, overlap, unfilling, and expansion), and analyzed their changes on a time scale. The results revealed that there have been significant climate niche shifts (Schoener’s D < 0.2, niche similarity tests p > 0.01, niche equivalence tests p < 0.01) between the native and invaded areas (China) of P. canaliculata, which does not support the climate niche conservation hypothesis. The minimum temperature of the coldest month (Bio 6) and precipitation seasonality (Bio 15) were the key climate variables driving the climatic niche shift, and P. canaliculata can survive in colder and more arid regions than their native counterparts. The changes in the niche shifts in P. canaliculata on a time scale show significant temporal heterogeneity, and its invasion behavior in China presents a discontinuous and phased expansion pattern, with strong adaptability to new environments. The results are of great significance for the future development of more accurate ecological niche model (ENM), the formulation of more targeted prevention and control strategies, and the study of adaptive evolution mechanisms of invasive species. Full article

Argentina is among the top consumers of herbicides, yet studies on their environmental and health impact remain scarce. This work aimed to evaluate the effects of herbicide exposure on Pomacea canaliculata as potential biomarkers of contamination. Specifically, we investigated whether paraquat (Pq) and fluroxypyr (Fx) alter enzymatic antioxidant defenses in tissues following acute exposure and induce histological modifications in the digestive gland (DG), particularly in symbiotic corpuscles, after chronic exposure. The nominal no-observed-effect concentration on lethality (NOEC_L) values were 3.62 µg/g dry mass (DM) for Pq and 10.42 µg/g DM for Fx. After acute exposure, superoxide dismutase activity decreased in the DG but increased in the kidney for both herbicides. Catalase activity decreased in the gills but increased in the kidneys of exposed snails, while glutathione-S-transferase activity increased in the DG and kidney after Pq exposure. Following chronic exposure (Pq: 1.45 µg/g DM; Fx: 6.94 µg/g DM), epithelial thickening and vacuolization were observed in Fx-exposed snails. Morphometric analysis of the DG showed that Pq reduced the epithelial occupancy of the symbiont’s vegetative form while increasing its cystic form. These findings indicate that both herbicides impact antioxidant defenses, DG function and host–symbiont interactions, reinforcing the suitability of P. canaliculata as bioindicator organisms. Full article

Aquatic alien species (AAS) have had a major impact on freshwater ecosystems, including Lake Naivasha in Kenya. Here, the ecosystem has undergone tremendous changes and multiple species introductions over the past 100 years, and molluscs have experienced a major decline in species diversity. The East African Rift Lakes have experienced a steady rise in lake levels since 2010. We investigated the impact of recent ecosystem changes on the lakes’ molluscs by determining the current mollusc diversity and its composition. We also reconstruct the history of faunal change and turnover over the last 100 years and discuss the future of molluscs in the lake and the implications in a One Health context. The combined effects of rising water levels and the decline of the crayfish Procambarus clarkii are likely to be responsible for the resurgence of Lake Naivasha’s mollusc fauna. The current fauna consists of three global invaders of American origin, one of which is new to East Africa (Pseudosuccinea columella) and another of which has only recently begun to spread (Pomacea canaliculata). A further three species are native to Africa, two of which are known from historical records, while one is new to Lake Naivasha (Bulinus forskalii). All native species are of public health (Biomphalaria sudanica) and veterinary health (Bulinus tropicus, Bulinus forskalii) concern. The current biodiversity of molluscs has reached the same level as in historical times, but the species composition is remarkably different. Full article

Apple snails (Pomacea canaliculata), one of the 100 most serious invasive species in the world, have invaded mangrove wetlands due to their salinity tolerance. We firstly prepared a plant molluscicide against apple snails based on the mangrove Aegiceras corniculatum in coastal wetland. The effects of four mangrove extracts from A. corniculatum, including ethanol extract (EE), petroleum ether extract (PEE), ethyl acetate extract (EAE), and n-butanol extract (BE), were studied for molluscicidal activity against apple snails in a saline environment. The LC₅₀ values at 48 h of EE, PEE, EAE, and BE were 25 mg/L, 123 mg/L, 170 mg/L, and 14 mg/L, respectively. BE had the highest molluscicidal value (96.7%) against apple snails at 48 h. At 48 h, BE of A. corniculatum leaves significantly decreased the soluble sugar content, soluble protein content, acetylcholinesterase, and glutathione of apple snails to 4.25 mg/g, 29.50 mg/g, 947.1 U/gprot, and 6.22 U/gprot, respectively, compared to those in the control. The increased BE concentration significantly enhanced the malondialdehyde and aspartate aminotransferase contents to 4.18 mmol/gprot and 18.9 U/gprot at 48 h. Furthermore, the damage in the hepatopancreas tissue of apple snails increased, and the cellular structure became necrotic as the concentration of BE from A. corniculatum increased. The content of palmitic acid in BE of A. corniculatum leaves was the highest (10.9%), possibly be a toxic ingredient against apple snails. The n-butanol extract of A. corniculatum leaves showed a potential to control apple snails in the brackish water, and its plantation was beneficial to control the further spread of apple snails in mangrove wetlands. Full article