Gastrointestinal parasite diversity in two contrasting guanaco (Lama guanicoe) populations of Argentina: Comparing Chacoan and Patagonian populations.

Comparative genomics of parasitoid lifestyle as exemplified by Mermithidae and Nematomorpha.

Plant-parasitic nematodes, especially root-knot nematodes (RKNs) of the genus Meloidogyne, are major agricultural pests, causing crop yield losses of up to 80% in vegetables. Rapid reproduction intensifies soil infestation, and reliance on synthetic nematicides is declining due to environmental and health risks, necessitating sustainable alternatives. This study investigates the nematicidal potential of Carissa carandas L. methanolic seed extract, known for bioactive compounds, against Meloidogyne incognita juveniles (J2) and egg masses. In vitro assays at concentrations of 250, 500, and 1000ppm demonstrated that the extract significantly increased J2 mortality and inhibited egg hatching in a concentration- and time-dependent manner. At 1000ppm, the extract caused pronounced nematode anatomical disruptions, with Scanning Electron Microscopy (SEM) revealing severe structural changes in egg masses. An in-vivo pot experiment assessed C. carandas seed powder against M. incognita on muskmelon cv. 'Arkasiri' in a glasshouse setting, comparing its efficacy with Fluopyram, a commercial nematicide. Both treatments, applied 15- and 30-days post-inoculation, markedly improved plant growth parameters and reduced nematode indicators such as root galls and soil nematode populations. At 30days, C. carandas treatment achieved a 94.26% reduction in root galls, while Fluopyram achieved 96.78%, with the latter showing a 99.10% decrease in nematode populations. GC-MS analysis of the extract identified bioactive compounds, including fatty acids, likely responsible for nematicidal effects. These results indicate that C. carandas seed extract offers a promising, eco-friendly approach for managing M. incognita, supporting plant-based nematicidal development for integrated pest management.

The impact of microplastics on soil micro-food webs is regulated by biochar and earthworms.

Human activities have dramatically increased nitrogen (N) inputs to terrestrial ecosystems, with cascading effects on soil biodiversity and function. Soil nematodes, the most abundant animals on Earth, play critical roles in nutrient cycling and ecosystem health. Although numerous studies have examined N effects on soil nematodes, crucial knowledge gaps remain regarding how these varying responses depend on fundamental soil properties like organic carbon (C) content and soil acidity, particularly across soils with contrasting baseline properties under identical fertilization regimes. Through a long-term field experiment with soils differing in organic C contents, here we show that baseline soil conditions strongly affect the effects of N enrichment on soil nematode communities. Specifically, N addition increased nematode abundance in C-rich soils, while significantly reducing it in C-poor soils through inducing soil acidification. Soil pH emerged as a critical filter regulating nematode responses to N enrichment, determining which trophic groups thrived or declined and thereby reshaping soil C cycling pathways. Results from a global meta-analysis further reveal that nematode abundance exhibited a hump-shaped relationship with soil pH, peaking at 5.9-6.0, while increasing monotonically with SOC. Together, our results demonstrate that local soil properties mediate N impacts on soil food webs more strongly than N input alone. By linking N inputs with nematode community shifts through measurable soil properties, our work provides a framework for predicting how global changes might alter belowground ecosystems. This knowledge is crucial for developing sustainable agricultural practices that maintain soil biodiversity while meeting crop production demands.

Conservation agriculture buffers the impact of irrigation on soil nematodes: a case study in Southern France

Linking anaerobic digestate application to soil microbial and nematode community structure, diversity, and functionality in maize cultivation

Parasitic infections in poultry production pose a significant challenge. Ascaridia galli is a nematode belonging to the phylum Nematoda that causes frequent infections along with significant morbidity and mortality in poultry birds, thereby leading to huge economic losses. A. galli has been detected in most of the species of poultry, including chickens, turkeys, geese, guinea fowl, and a wide variety of wild birds, with chicken being the main host. Clinical symptoms in birds include anorexia, ruffled feathers, weight loss, drop in egg production, anaemia, and diarrhoea, ultimately causing death. Upon post-mortem (PM) examination, partial or complete obstruction of the intestinal lumen alone or along with catarrhal to haemorrhagic enteritis was highly evident. Treatment with suitable anthelmintic and good management practices are the key components for the treatment, prevention and control of this disease.

Alpine forests at high elevations are critical for sustaining ecosystem processes and delivering essential ecological services. However, human trampling represents a pervasive disturbance that can profoundly alter soil biodiversity and ecosystem functioning. In this study, we evaluated the effects of varying levels of human trampling on soil nematode communities in the Pir-Panjal mountain range. Soil samples were collected from the 0-15 cm layer across four trampling intensities: non-trampled control (C), low trampling (LT), moderate trampling (MT), and extreme trampling (ET). Total nematode abundance, as well as abundances of bacterivores, fungivores, herbivores, omnivores, and predators, were significantly reduced under extreme trampling compared to control, LT, and MT. Specifically, extreme trampling caused declines of 69.3% in total nematode abundance, 67.7% in bacterivores, 69.6% in fungivores, 78.0% in herbivores, 78.4% in omnivores, and 48.0% in predators relative to control conditions. At the generic level, diversity was significantly lower at LT sites compared to control and other trampled sites. Generic richness increased under MT, decreased under ET, and remained unchanged under LT compared to control. Similarly, the maturity index (MI) was significantly reduced in MT and ET relative to control and LT, reflecting shifts in community composition toward opportunistic taxa under higher trampling pressure. These findings demonstrate that human trampling induces marked alterations in nematode abundance, diversity, and functional indices, which are closely linked to changes in belowground abiotic conditions and trophic structure. These insights are critical for guiding alpine forest management, emphasizing the need for strategic trail planning, access regulation, and targeted restoration efforts in areas experiencing high human disturbance to maintain soil health and ecosystem resilience

Soil nematode communities and food web structure in Portuguese rice agroecosystems

Global guardians of the desert: The unseen world of soil nematodes in Earth's most extreme ecosystems

Fertilization management reshapes plant-nematode interactions across global ecosystems.

Soil nematodes are integral to soil micro-food webs and serve as sensitive bioindicators of soil ecological condition. However, how forest vegetation and soil properties interact to shape nematode community assembly, network structure, and functional stability remains inadequately understood. Using 18S rRNA gene amplicon sequencing coupled with phylogenetic null modeling, we examined soil nematode communities across four forest types along a succession gradient. Although taxonomic diversity (e.g., Shannon and Pielou indices) differed significantly among forest types, network topology and stochastic assembly processes were more closely associated with community restructuring and co-occurrence patterns. This suggests that, while diversity is not irrelevant, network- and assembly-based metrics provide complementary and often more sensitive indicators of nematode community responses to forest type. Co-occurrence network analysis revealed that mixed forests fostered more complex and potentially stable networks, whereas plantations formed dense but potentially vulnerable networks. Assembly processes were not dominated by strong deterministic selection (|βNTI| ≤ 2 for most comparisons), a pattern consistent with undominated processes (e.g., ecological drift, weak environmental filtering). Dispersal limitation played a negligible role in this system. Partial Least Square Path Modeling identified spatial factors and key soil properties (e.g., pH, electrical conductivity, soil water content, and organic carbon) as primary drivers of community structure. Our findings indicate that assessing soil food web health should integrate network analysis and stochasticity metrics rather than rely solely on taxonomic diversity. For sustainable forest management, mixed-species stands are preferable to monoculture plantations, and maintaining soil physicochemical heterogeneity is critical for community stability.

ABSTRACTThe impact of Bacillus firmus–based bionematicides on rhizosphere microbiota and plant performance remains poorly understood in complex agroecosystems. This study evaluated the effects of B. firmus application on soil microbial communities, nematode dynamics, and soybean productivity in the Pampa biome. Our results demonstrate that B. firmus significantly modulates the composition and diversity of soil microbiota, with effects varying across locations and over time. Treated areas exhibited shifts in bacterial communities, including increased abundance of beneficial taxa, while fungal diversity tended to decrease, likely due to the combined effect of the fungicide used in seed treatment. Despite persistent populations of target nematodes such as Pratylenchus brachyurus and Heterodera glycines, treated areas showed reduced root infestation in specific stages and locations. Importantly, the application of B. firmus consistently enhanced soybean shoot and root growth, resulting in productivity gains of 6%–7% across all sites. These findings reveal that B. firmus not only contributes to plant growth promotion but also induces significant, yet context‐dependent, shifts in rhizosphere microbial communities. The study highlights the ecological complexity of microbial responses to biocontrol agents and underscores the importance of integrating microbiome dynamics into sustainable nematode management strategies in agroecosystems.

Though individually rare, rare diseases collectively affect nearly 1 out of 30 individuals, highlighting the continued need for and importance of research on these disorders. We argue that the recent work in identifying and diagnosing previously undiagnosed diseases is only the beginning. To meet this need, animal models have played an important role in studying rare and undiagnosed diseases by providing functional and biological information to validate candidate disease genes. Specifically, nonmammalian models like nematode worms (Caenorhabditis elegans), fruit flies (Drosophila melanogaster), and zebrafish (Danio rerio) provide significant advantages to the scientific community and have, unsurprisingly, been essential in many advances in the rare disease field and beyond. Given this success, new priorities are emerging on how to use these animal models to drive therapeutic-focused research. In this review, we discuss how these common nonmammalian models have pointed to new therapeutic directions and are used to both test and create therapies. Through the characterization of genetic mechanisms and emerging protocols like drug repurposing, animal models have never been as important to the rare disease field as they are now. Ongoing mechanistic discoveries and therapeutic advances not only have the potential to improve our management of rare disease but may also have implications for more common disorders across multiple areas of medicine.

Plants sense a diverse array of small molecules and macromolecules derived from their natural environment, including diverse microbe-associated molecular patterns (MAMPs) that can trigger defense responses. Several MAMPs have been shown to prime plants for enhanced defense, providing extended protection against pathogens with minimal fitness costs. However, the extent to which conserved small molecule signatures of other phyla contribute to priming of plant defenses is unclear. Here, we demonstrate that exposure of seeds or plants to the ascaroside ascr#18, a pheromone secreted by plant-parasitic and free-living soil nematodes, primes immune genes for enhanced expression upon pathogen challenge, thereby increasing resistance to diverse microbial pathogens. We further show that ascr#18-induced priming is associated with the formation of open chromatin in the regulatory regions of defense genes. Defense priming and disease protection by ascr#18 is compromised in Arabidopsis mutants defective in the receptor of ascr#18, the leucine-rich repeat receptor-like kinase NILR1. Defense priming by ascr#18 is retained under field conditions, demonstrating potential of ascaroside treatment as a crop protection strategy to reduce pesticide usage. Our findings provide insight into the molecular basis of defense priming by ascr#18 and demonstrate how evolutionarily conserved small molecule signatures of plant-associated macrobiota modulate immunity.

Changes of soil nematode communities affect the soil labile phosphorus under nitrogen addition in Pinus taiwanensis forests

Dung-applied anthelmintic drug moxidectin alters free-living soil nematode communities.

Long-term impacts of nitrogen addition on soil nematode communities in alpine meadows: soil acidification and functional responses

Insulin/Insulin-like growth factor 1 (IGF-1) signaling (IIS) is a pleiotropic signaling pathway that functions across tissues to coordinate phenotypic changes in response to nutrient status. Thus, the ubiquity of the IIS pathway hinders efforts to elucidate the mechanisms driving specific IIS-related phenotypes. Previous research in the nematode worm C. elegans has demonstrated that loss of function of the IIS transmembrane receptor (IR) ortholog, DAF-2, results in a doubled lifespan and enhanced learning and memory behaviors in young and aged animals. However, these findings are the result of reducing DAF-2 receptor function rather than modulating ligand-receptor interactions. In the current study, we aimed to dissect ligand-receptor interactions that may regulate associative behaviors apart from canonical IIS lifespan phenotypes in C. elegans. To this end, we performed targeted genetic screening of Insulin-like Peptides (ILPs) previously identified as DAF-2 antagonists to test their role in learning and memory phenotypes. We discovered that only a single uncharacterized ILP, INS-17, is required for learning and memory. We also demonstrate that INS-17 is sufficient to confer extended memory ability and can promote the maintenance of learning and memory with age. Additionally, we observe that INS-17 regulates associative behaviors independent of lifespan, uncoupling some IIS-mutant phenotypes. We find that regulation of the ins-17 genetic locus explains its unique requirement among ILPs for learning and memory behaviors. Finally, we found that INS-17 acts to signal a state of nutrient deprivation. This activity is required to properly process stimulus valence to promote advantageous behaviors. Our findings deepen the understanding of how IIS can regulate specific phenotypic outputs in response to changes in internal metabolic states.