-
Frontiers in Neuroscience 2024Most species of the bone-devouring marine annelid, display distinct sexual dimorphism with macroscopic sedentary females rooted in bones and free-living microscopic...
Most species of the bone-devouring marine annelid, display distinct sexual dimorphism with macroscopic sedentary females rooted in bones and free-living microscopic dwarf males. The paedomorphic male resembles the non-feeding metatrochophore larva in size, presence of eight pairs of chaetae, and a head ciliation potentially representing a residual prototroch. The male development may thus uniquely reiterate and validate the theoretical heterochrony process "progenesis", which suggests that an accelerated sexual maturation and early arrest of somatic growth can lead to a miniaturized and paedomorphic adult. In this study, we describe the postembryonic larval and juvenile organogenesis of to test for a potential synchronous arrest of somatic growth during male development. Five postembryonic stages could be distinguished, resembling day one to five in the larval development at 10°C: (0D) first cleavage of fertilized eggs (embryos undergo unequal spiral cleavage), (1D) pre-trochophore, with apical organ, (2D) early trochophore, + prototroch, brain, circumesophageal connectives and subesophageal commissure, (3D) trochophore, + telotroch, four ventral nerves, (4D) early metatrochophore, + protonephridia, dorsal and terminal sensory organs, (5D) metatrochophore, + two ventral paratrochs, mid-ventral nerve, posterior trunk commissure, two dorsal nerves; competent for metamorphosis. The larval development largely mirrors that of other lecithotrophic annelid larvae but does not show continuous chaetogenesis or full gut development. Additionally, larvae exhibit an unpaired, mid-dorsal, sensory organ. Female individuals shed their larval traits during metamorphosis and continue organogenesis (including circulatory system) and extensive growth for 2-3 weeks before developing oocytes. In contrast, males develop sperm within a day of metamorphosis and display a synchronous metamorphic arrest in neural and muscular development, retaining a large portion of larval features post metamorphosis. Our findings hereby substantiate male miniaturization in to be the outcome of an early and synchronous offset of somatic development, fitting the theoretical process "progenesis". This may be the first compelling morpho-developmental exemplification of a progenetic origin of a microscopic body plan. The presented morphological staging system will further serve as a framework for future examination of molecular patterns and pathways determining development.
PubMed: 38562300
DOI: 10.3389/fnins.2024.1369274 -
Ecology and Evolution Jul 2023The South China Sea (SCS) basin is hypothesized to host distinct and bathymetrically differentiated fauna due to its semi-enclosed basin and three-layer circulation...
The South China Sea (SCS) basin is hypothesized to host distinct and bathymetrically differentiated fauna due to its semi-enclosed basin and three-layer circulation system. To test this hypothesis, three cow falls are artificially deployed at separate depths (655, 1604, and 3402 m) on Zhongnan seamount in the middle SCS, and the associated worms, spp. are selected as targets to explore their diversity, phylogeny, and zonation pattern. Analyses of collected specimens reveal three new species, which were then nominally described and named as sp. nov. (655 m), sp. nov. (1604 and 3402 m), and sp. nov. (3402 m), and one known species ( lineage II). Metabarcoding analyses on cow-fall sediments reveal seven additional Operated Taxonomic Units (OTUs) assigned to , increasing the diversity to 10 species/OTUs in the middle SCS. Their distribution along depth shows increasing diversity toward the deeper sites. Phylogenetic inferences recover closely related to from the Southwest Atlantic, forming a lineage deeply divergent from others. The nine deep-water species/OTUs are scattered in three distinct lineages showing closer phylogenetic relationships between 1604- and 3402-m counterparts. The lineage formed by and is distinct from other non-SCS congeners both morphologically and genetically. These results suggest multiple independent invasions of to the SCS, a new lineage potentially endemic to the SCS, and a strong zonation pattern related to depth, especially between the shallow (655 m) and the deep (1604 and 3402 m) sites. The semi-enclosed feature combined with the physical structure of the SCS may contribute to such a pattern. This work is registered in ZooBank under: urn:lsid:zoobank.org:pub:317771C8-42D717-4765-A168-B3BE99B09FBF.
PubMed: 37470027
DOI: 10.1002/ece3.10256 -
The Science of the Total Environment Aug 2023The contamination of greenhouse vegetable soils with antibiotics and antibiotic resistance genes (ARGs), caused by the application of livestock and poultry manure, is a...
The contamination of greenhouse vegetable soils with antibiotics and antibiotic resistance genes (ARGs), caused by the application of livestock and poultry manure, is a prominent environmental problem. In this study, the effects of two ecological earthworms (endogeic Metaphire guillelmi and epigeic Eisenia fetida) on the accumulation and transfer of chlortetracycline (CTC) and ARGs in a soil-lettuce system were studied via pot experiments. The results revealed that earthworm application accelerated the removal of the CTC from the soil and lettuce roots and leaves, with the CTC content reducing by 11.7-22.8 %, 15.7-36.1 %, and 8.93-19.6 % compared with that of the control, respectively. Both earthworms significantly reduced the CTC uptake by lettuce roots from the soil (P < 0.05) but did not change the CTC transfer efficiency from the roots to leaves. The high-throughput quantitative PCR results showed that the relative abundance of ARGs in the soil and lettuce roots and leaves decreased by 22.4-27.0 %, 25.1-44.1 %, and 24.4-25.4 %, respectively, with the application of earthworms. Earthworm addition decreased the interspecific bacterial interactions and the relative abundance of mobile genetic elements (MGEs), which helped reduce the dissemination of ARGs. Furthermore, some indigenous soil antibiotic degraders (Pseudomonas, Flavobacterium, Sphingobium, and Microbacterium) were stimulated by the earthworms. The results of redundancy analysis indicated that the bacterial community composition, CTC residues, and MGEs were the main parameters affecting the distribution of ARGs, accounting for 91.1 % of the total distribution. In addition, the bacterial function prediction results showed that the addition of earthworms reduced the abundance of some pathogenic bacteria in the system. Overall, our findings imply that earthworm application can substantially reduce the accumulation and transmission risk of antibiotics and ARGs in soil-lettuce systems, providing a cost-effective soil bioremediation practice for addressing antibiotic and ARGs contamination to guarantee the safety of vegetables and human health.
Topics: Animals; Humans; Anti-Bacterial Agents; Oligochaeta; Chlortetracycline; Lactuca; Drug Resistance, Microbial; Bacteria; Genes, Bacterial; Vegetables; Soil; Manure; Soil Microbiology
PubMed: 37149170
DOI: 10.1016/j.scitotenv.2023.163907 -
Molecular Phylogenetics and Evolution Oct 2023Siboglinid tubeworms are found at chemosynthetic environments worldwide and the Vestimentifera clade is particularly well known for their reliance on chemoautotrophic...
Siboglinid tubeworms are found at chemosynthetic environments worldwide and the Vestimentifera clade is particularly well known for their reliance on chemoautotrophic bacterial symbionts for nutrition. The mitochondrial genomes have been published for nine vestimentiferan species to date. This study provides new complete mitochondrial genomes for ten further Vestimentifera, including the first mitochondrial genomes sequenced for Alaysia spiralis, Arcovestia ivanovi, Lamellibrachia barhami, Lamellibrachia columna, Lamellibrachia donwalshi, and unnamed species of Alaysia and Oasisia. Phylogenetic analyses combining fifteen mitochondrial genes and the nuclear 18S rRNA gene recovered Lamellibrachia as sister to the remaining Vestimentifera and Riftia pachyptila as separate from the other vent-endemic taxa. Implications and auxiliary analyses regarding differing phylogenetic tree topologies, substitution saturation, ancestral state reconstruction, and divergence estimates are also discussed. Additionally, a new species of Alaysia is described from the Manus Basin.
Topics: Animals; Polychaeta; Phylogeny; Genome, Mitochondrial; Annelida; Bacteria
PubMed: 37451325
DOI: 10.1016/j.ympev.2023.107872 -
Molecular Biology and Evolution Aug 2023The roles of DNA methylation in invertebrates are poorly characterized, and critical data are missing for the phylum Annelida. We fill this knowledge gap by conducting...
The roles of DNA methylation in invertebrates are poorly characterized, and critical data are missing for the phylum Annelida. We fill this knowledge gap by conducting the first genome-wide survey of DNA methylation in the deep-sea polychaetes dominant in deep-sea vents and seeps: Paraescarpia echinospica, Ridgeia piscesae, and Paralvinella palmiformis. DNA methylation calls were inferred from Oxford Nanopore sequencing after assembling high-quality genomes of these animals. The genomes of these worms encode all the key enzymes of the DNA methylation metabolism and possess a mosaic methylome similar to that of other invertebrates. Transcriptomic data of these polychaetes support the hypotheses that gene body methylation strengthens the expression of housekeeping genes and that promoter methylation acts as a silencing mechanism but not the hypothesis that DNA methylation suppresses the activity of transposable elements. The conserved epigenetic profiles of genes responsible for maintaining homeostasis under extreme hydrostatic pressure suggest DNA methylation plays an important adaptive role in these worms.
Topics: Animals; Epigenome; Annelida; Polychaeta; Gene Expression Profiling; Genome; DNA Methylation
PubMed: 37494294
DOI: 10.1093/molbev/msad172 -
Ecotoxicology and Environmental Safety Dec 2023Ivermectin (IVM) is a dewormer commonly utilized in animal farming. Nevertheless, there is a deficiency of research on the bioecotoxicity of IVM in soil. In this study,...
Ivermectin (IVM) is a dewormer commonly utilized in animal farming. Nevertheless, there is a deficiency of research on the bioecotoxicity of IVM in soil. In this study, earthworms were utilized as test animals to investigate the ecotoxicological impacts of IVM. The experiment lasted 28 days and involved adding varied doses of IVM to a culture substrate of soil mixed with cow dung and feeding it to earthworms. The experiment entailed recording earthworm weight, number of earthworm cocoons, histological damage, oxidative stress indicators, and gene expression levels. The analysis results showed that earthworm growth and reproduction were hampered by IVM. Moreover, pathological damage to the earthworms increased with increasing IVM concentration, which caused increased oxidative damage to the earthworms. These findings offer a summary of the impact of IVM on earthworms and a reference point for future research examining the ecological implications of IVM.
Topics: Animals; Cattle; Female; Oligochaeta; Ivermectin; Soil Pollutants; Soil; Ecotoxicology
PubMed: 37979365
DOI: 10.1016/j.ecoenv.2023.115709 -
Chemosphere Oct 2023Cadmium (Cd) and fenpyroximate are common soil contaminants found together in the field, but their combined toxicity to terrestrial invertebrates has not been studied....
Cadmium (Cd) and fenpyroximate are common soil contaminants found together in the field, but their combined toxicity to terrestrial invertebrates has not been studied. Therefore, earthworms Aporrectodea jassyensis and Eisenia fetida were exposed into Cd (5, 10, 50 and 100 μg/g) and fenpyroximate (0.1, 0.5, 1, and 1.5 μg/g) and their mixture, and multiple biomarker responses (mortality, catalase (CAT), superoxide dismutase (SOD), total antioxidant activity (TAC), lipid peroxidation (MDA), protein content, weight loss and subcellular partitioning) were determined to estimate health status and mixture effect. MDA, SOD, TAC, and weight loss were significantly correlated with Cd in total internal and debris (p < 0.01). Fenpyroximate altered the subcellular distribution of Cd. It appears that maintaining Cd in a non-toxic form was the earthworms' primary Cd detoxification strategy. CAT activity was inhibited by Cd, fenpyroximate, and their combined presence. BRI values for all treatments indicated a major and severe alteration in earthworm's health. The combined toxicity of Cd and fenpyroximate was greater than the toxicity of either substance alone. According to EAI, all combined treatments exhibited a clear antagonistic effect. In general, the sensitivity of A. jassyensis was greater than that of E. fetida.
Topics: Animals; Cadmium; Oligochaeta; Soil Pollutants; Biomarkers; Superoxide Dismutase; Soil
PubMed: 37364643
DOI: 10.1016/j.chemosphere.2023.139329 -
Chemosphere Aug 2023The interest in the effect of microplastics (MPs) on the terrestrial environment has been increasing recently. Different species of earthworms have been used to study...
The interest in the effect of microplastics (MPs) on the terrestrial environment has been increasing recently. Different species of earthworms have been used to study the effects of MPs on different aspects of earthworm health. However, there is still a need for more studies because different studies report different effects on earthworms depending on the properties (e.g., types, shapes, sizes) of MPs in the environment and exposure conditions (e.g., exposure period). This study used Eisenia fetida as a test earthworm species to investigate the effect of different concentrations of low-density polyethylene (LDPE) MPs (≤125 μm) in soil on the growth and reproduction of earthworms. The exposure of the earthworms to the different concentrations of LDPE MPs (0-3% w/w) for 14 d and 28 d neither caused death of the earthworms nor showed significant effects on the earthworm weights in this study. The number of cocoons produced by the exposed earthworms were also similar to that of the controls (i.e., no exposure to MPs). Some previous studies reported similar results to what have been observed in this study, while some studies reported different results. On the other hand, the number of ingested MPs by the earthworms increased with increasing MPs concentrations in soil, suggesting a potential for damage to digestive tract. Also, the earthworm skin surface was damaged after exposure to MPs. The ingested MPs and the skin surface damage suggest that there is a potential for adverse effects on the earthworm growth after a longer-term exposure. Overall, the results of this study show that the effects of MPs on earthworms need to be studied using various endpoints including growth, reproduction, ingestion, and skin damage and such effects can be different depending on the exposure conditions such as MPs concentration and exposure period.
Topics: Animals; Microplastics; Polyethylene; Plastics; Oligochaeta; Soil Pollutants; Soil
PubMed: 37196794
DOI: 10.1016/j.chemosphere.2023.138945 -
The Science of the Total Environment Sep 2023In this study, environmental behavior and toxicity of cyflumetofen (CYF) enantiomers were evaluated comprehensively in a soil-earthworm system. In the earthworm (Eisenia... (Review)
Review
In this study, environmental behavior and toxicity of cyflumetofen (CYF) enantiomers were evaluated comprehensively in a soil-earthworm system. In the earthworm (Eisenia foetida), (+)-CYF was preferentially accumulated, and acute toxicity of Rac-CYF was greater than that of (+)-CYF and (-)-CYF, indicating that the combination of CYF enantiomers increased the toxicity. As a measure of chronic toxicity, compared with (-)-CYF-treated earthworms, malondialdehyde accumulation was higher in (+)-CYF-treated earthworms, indicating a more severe oxidative stress response. In a DNA comet plot, the trailing distance in the (+)-CYF treatment was 1.97 times greater than that in the (-)-CYF-treated, revealing more severe genotoxicity with (+)-CYF. However, (-)-CYF was more likely than (+)-CYF to activate the earthworm detoxification enzyme pathway. With (+)-CYF treatment, the number of differentially expressed genes (DEGs) involved in the pathogenic pathway increased significantly, whereas with (-)-CYF-treatment, more DEGs were involved in P450 and glutathione S-transferase (GST) detoxification metabolic pathways, including high expression of the genes chi-III, GST-S-1, and GST-alpha-5. The main metabolites of the CYF enantiomers were A-2, A-12, B-1, AB-1, AB-7, and B-3, which exhibited potential ecotoxicity. In general, CYF was stereoselective in the soil-earthworm ecosystem, with (+)-CYF causing a higher genotoxicity risk than that of (-)-CYF. The study provides insight into the selective toxicity mechanisms of chiral CYF and contributes to a theoretical basis for risk assessment of low-risk pesticides.
Topics: Animals; Oligochaeta; Ecosystem; Bioaccumulation; Soil Pollutants; Soil
PubMed: 37263435
DOI: 10.1016/j.scitotenv.2023.164541 -
Environmental Pollution (Barking, Essex... Aug 2023Microplastics (MPs) in soil undergo different aging processes such as photoaging, mechanical abrasion and biodegradation, leading to alterations in the surface...
Microplastics (MPs) in soil undergo different aging processes such as photoaging, mechanical abrasion and biodegradation, leading to alterations in the surface properties of MPs. In this study, we investigated the adsorption-desorption of chlorpyrifos (CPF) on pristine and UV light-aged low-density polyethylene (LDPE) and biodegradable (Bio) MPs that were derived from plastic mulch films. We also tested the bioconcentration of pristine and aged MPs (LDPE- and Bio-MPs aged under UV light and LDPE-MPs aged in three different soils) associated with CPF by earthworms (Lumbricus terrestris). The results showed that UV-aged MPs showed higher CPF adsorption capacities than pristine MPs, with the adsorption capacities at 184.9 ± 5.3, 200.5 ± 1.8, 193.0 ± 8.7, and 215.9 ± 1.1 μg g for pristine LDPE-, UV-aged LDPE-, pristine Bio- and UV-aged Bio-MPs, respectively. The desorption rate of CPF from UV-aged LDPE-MPs within 48 h was lower than the desorption from pristine ones (28.8 ± 7.7% vs. 40.0 ± 3.9%), while both pristine and UV-aged Bio-MPs showed very low CPF desorption rates. A 4-day Petri dish experiment showed that UV-aged MPs were significantly less concentrated in earthworm casts than pristine counterparts (52% and 36% lower for UV-aged LDPE- and Bio-MPs), while UV-aged MPs with adsorbed CPF were concentrated significantly more than UV-aged MPs without CPF. Interestingly, LDPE-MPs aged in soil with a high carbon, nitrogen, and carbon-to-nitrogen ratio were significantly more concentrated in earthworm casts than pristine LDPE-MPs. In conclusion, UV-aged MPs acted as stronger vectors for CPF than pristine MPs. The bioconcentration of MPs differed significantly due to microplastic aging, as well as the combined effect with CPF. Moreover, LDPE-MPs aged in soil with enriched carbon and nitrogen were significantly concentrated in earthworm casts. Further studies on the environmental behaviours of aged MPs associated with other pollutants in soil, especially soils high in carbon and nitrogen, are needed.
Topics: Animals; Microplastics; Plastics; Chlorpyrifos; Polyethylene; Adsorption; Bioaccumulation; Soil; Oligochaeta
PubMed: 37247767
DOI: 10.1016/j.envpol.2023.121910