Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.091
Filtrar
1.
PLoS One ; 16(9): e0255674, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34529673

RESUMO

Earthworms (Crassiclitellata) being ecosystem engineers significantly affect the physical, chemical, and biological properties of the soil by recycling organic material, increasing nutrient availability, and improving soil structure. The efficiency of earthworms in ecology varies along with species. Therefore, the role of taxonomy in earthworm study is significant. The taxonomy of earthworms cannot reliably be established through morphological characteristics because the small and simple body plan of the earthworm does not have anatomical complex and highly specialized structures. Recently, molecular techniques have been adopted to accurately classify the earthworm species but these techniques are time-consuming and costly. To combat this issue, in this study, we propose a machine learning-based earthworm species identification model that uses digital images of earthworms. We performed a stringent performance evaluation not only through 10-fold cross-validation and on an external validation dataset but also in real settings by involving an experienced taxonomist. In all the evaluation settings, our proposed model has given state-of-the-art performance and justified its use to aid earthworm taxonomy studies. We made this model openly accessible through a cloud-based webserver and python code available at https://sites.google.com/view/wajidarshad/software and https://github.com/wajidarshad/ESIDE.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Aprendizado de Máquina , Oligoquetos/classificação , Fotografação/instrumentação , Animais , Simulação por Computador , Ecossistema , Oligoquetos/fisiologia
2.
PLoS One ; 16(8): e0241945, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34460828

RESUMO

Abundance and distribution of earthworms in agricultural fields is frequently proposed as a measure of soil quality assuming that observed patterns of abundance are in response to improved or degraded environmental conditions. However, it is not clear that earthworm abundances can be directly related to their edaphic environment, as noted in Darwin's final publication, perhaps limiting or restricting their value as indicators of ecological quality in any given field. We present results from a spatially explicit intensive survey of pastures within United Kingdom farms, looking for the main drivers of earthworm density at a range of scales. When describing spatial variability of both total and ecotype-specific earthworm abundance within any given field, the best predictor was earthworm abundance itself within 20-30 m of the sampling point; there were no consistent environmental correlates with earthworm numbers, suggesting that biological factors (e.g. colonisation rate, competition, predation, parasitism) drive or at least significantly modify earthworm distributions at this spatial level. However, at the national scale, earthworm abundance is well predicted by soil nitrate levels, density, temperature and moisture content, albeit not in a simple linear fashion. This suggests that although land can be managed at the farm scale to promote earthworm abundance and the resulting soil processes that deliver ecosystem services, within a field, earthworm distributions will remain patchy. The use of earthworms as soil quality indicators must therefore be carried out with care, ensuring that sufficient samples are taken within field to take account of variability in earthworm populations that is unrelated to soil chemical and physical properties.


Assuntos
Oligoquetos/fisiologia , Solo/química , Agricultura/métodos , Animais , Biodiversidade , Ecossistema , Fazendas , Reino Unido
3.
Commun Biol ; 4(1): 612, 2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-34021246

RESUMO

Earthworm activity modifies soil structure and promotes important hydrological ecosystem functions for agricultural systems. Earthworms use their flexible hydroskeleton to burrow and expand biopores. Hence, their activity is constrained by soil hydromechanical conditions that permit deformation at earthworm's maximal hydroskeletal pressure (≈200kPa). A mechanistic biophysical model is developed here to link the biomechanical limits of earthworm burrowing with soil moisture and texture to predict soil conditions that permit bioturbation across biomes. We include additional constraints that exclude earthworm activity such as freezing temperatures, low soil pH, and high sand content to develop the first predictive global map of earthworm habitats in good agreement with observed earthworm occurrence patterns. Earthworm activity is strongly constrained by seasonal dynamics that vary across latitudes largely due to soil hydromechanical status. The mechanistic model delineates the potential for earthworm migration via connectivity of hospitable sites and highlights regions sensitive to climate.


Assuntos
Distribuição Animal , Ecossistema , Oligoquetos/fisiologia , Solo/química , Movimentos da Água , Agricultura , Animais , Fenômenos Mecânicos
4.
J Vis Exp ; (170)2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33871458

RESUMO

Although vertebrates are indispensable to biomedical research, studies are often limited by factors such as cost, lengthy internal review, and ethical considerations. We present the earthworm as an alternative, low-cost, invertebrate applicable to certain preliminary vasculature studies. Due to the surgical availability of the earthworm's dorsal vessels, ventral vessels, and five pairs of pseudo hearts, earthworms are readily accessible, offer low-cost maintenance, and require administration of only small doses of a given compound. The earthworm model provides a simple closed vascular circulatory system with a hemoglobin structure similar to human blood. A protocol is provided for anaesthetizing the earthworms and performing surgical incisions to expose relevant blood vessels. Micropipettes for compound administration are formed by heating and pulling glass with a pipette puller and using a beveling system to create a micron-scale fine needle tip. The tips are then used with a micropositioner and microinjector to inject arbitrary compounds into the vascular system of an earthworm, repeatably, with the availability of large sample sizes and small compound volumes. Details on the intricacies of injection procedure are provided. The small vessel size of the earthworm is challenging, particularly in the case of the ventral vessel; however, mastery of the techniques presented offers high repeatability as a low-cost solution, making studies of very large sample size practical.


Assuntos
Vasos Sanguíneos/fisiologia , Modelos Biológicos , Oligoquetos/fisiologia , Animais , Circulação Sanguínea , Microinjeções
5.
Ecotoxicol Environ Saf ; 217: 112250, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33915450

RESUMO

Selenium (Se) is an essential microelement for human or animal health. At high concentrations, it can cause Se poisoning. Human activities (such as coal burning and mining) threaten soil biota by mobilizing high levels of Se. We used the earthworm Eisenia fetida as a bio-indicator of environmental pollutants to investigate Se acute toxicity, enrichment, and distribution through exposure tests using filter paper, artificial soil and cow manure. The 24 h- and 48 h-LC50 for the filter paper contact test were 2.7 and 1.52 µg/cm2. In artificial soil test, the 14 d-LC50 and 14 d-biomass inhibition concentration (IC20) were 63.86 and 59.81 mg/kg, respectively. The cow manure resulted in a 2.2- and 2.6-fold higher LC50 and IC20 than artificial soil results, respectively. Earthworms accumulated the largest Se load (89.47 mg/kg) in artificial soil containing 80 mg Se/kg and only accumulated 90.3 mg/kg in cow manure containing 160 mg Se/kg; 46.6-60.59% of the total Se was distributed in the tail of E. fetida. The Se enrichment rate (SERSe) and bioaccumulation factor (BAFSe) scored higher in artificial soil than in cow manure with the same Se concentration exposure, and the highest SERSe was 6.21 and 6.31 mg Se/kg earthworm/d, respectively. The highest BAFSe was 1.49 in artificial soil and 0.75 in cow manure. Our results demonstrate that selenite is more toxic to earthworms living in artificial soil than in cow manure. E. fetida possesses certain Se detoxification mechanisms by distributing Se in the tail.


Assuntos
Oligoquetos/fisiologia , Selênio/toxicidade , Poluentes do Solo/toxicidade , Animais , Bioacumulação , Bovinos , Feminino , Humanos , Dose Letal Mediana , Esterco , Solo , Poluentes do Solo/análise
6.
Zootaxa ; 4949(2): zootaxa.4949.2.11, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33903351

RESUMO

Three new species of Moniligaster Perrier, 1872, namely M. bahli Narayanan Julka, sp. nov., M. blakemorei Narayanan Julka, sp. nov. and M. keralensis Narayanan Julka, sp. nov. are described from materials collected from the Indian state of Kerala. Moniligaster cernosvitovi Gates, 1962, Moniligaster horsti Gates, 1940, Moniligaster michaelseni Gates, 1940 and Moniligaster stephensoni Gates, 1940 are recorded for the first time from the state. With the new findings, a total of 10 Moniligaster species are known from Kerala. Moniligaster species are restricted to southern peninsular India, except Moniligaster ivaniosi Manazhy, 2011, decribed from the Andaman Islands, outside the currently known distributional range of the genus. Hence we critically reviewed the original description and reinvestigated the holotype. As a result, Moniligaster ivaniosi is considered a junior synonym of Drawida nepalensis Michaelsen, 1907.


Assuntos
Oligoquetos , Animais , Biodiversidade , Índia , Lepidópteros , Oligoquetos/classificação , Oligoquetos/fisiologia
7.
Ecotoxicol Environ Saf ; 214: 112049, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33647852

RESUMO

The disposal of untreated sanitary sewage in the soil has several consequences for human health and leads to environmental risks; thus, it is necessary investigating, monitoring and remediating the affected sites. The aims of the current study are to evaluate ecotoxicological effects on Eisenia andrei earthworms exposed to soil subjected to sources of sanitary sewage discharge and to investigate whether prevention values established by the Brazilian legislation for soil quality, associated with the incidence of chemical substances in it, are satisfactory enough to assure the necessary quality for different organisms. Earthworms' behavior, reproduction, acetylcholinesterase activity, catalase, superoxide dismutase and malondialdehyde levels were evaluated. The reproduction and behavior of earthworms exposed to sanitary sewage were adversely affected. Increased superoxide dismutase and catalase activity acted as antioxidant defense mechanism. Significantly increased lipid peroxidation levels and acetylcholinesterase activity inhibition have indicated lipid peroxidation in cell membrane and neurotransmission changes, respectively. Results have confirmed that sanitary sewage induced oxidative stress in earthworms. In addition, based on biochemical data analysis, the integrated biomarker response (IBR) has evidenced different toxicity levels in earthworms between the investigated points. Finally, results have indicated that effluents released into the soil, without proper treatment, lead to contaminant accumulation due to soil saturation and it can hinder different processes and biological development taking place in the soil. In addition, the current study has shown that physical-chemical analyses alone are not enough to assess soil quality, since it is also requires adopting an ecotoxicological approach. Brazilian legislation focused on soil quality must be revised and new guiding values must be proposed.


Assuntos
Oligoquetos/fisiologia , Poluentes do Solo/análise , Animais , Antioxidantes/metabolismo , Brasil , Catalase/metabolismo , Ecotoxicologia , Poluição Ambiental/análise , Humanos , Malondialdeído/metabolismo , Oligoquetos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Esgotos , Solo/química , Superóxido Dismutase/metabolismo
8.
Int J Mol Sci ; 22(5)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673408

RESUMO

Regeneration of body parts and their interaction with the immune response is a poorly understood aspect of earthworm biology. Consequently, we aimed to study the mechanisms of innate immunity during regeneration in Eisenia andrei earthworms. In the course of anterior and posterior regeneration, we documented the kinetical aspects of segment restoration by histochemistry. Cell proliferation peaked at two weeks and remitted by four weeks in regenerating earthworms. Apoptotic cells were present throughout the cell renewal period. Distinct immune cell (e.g., coelomocyte) subsets were accumulated in the newly-formed blastema in the close proximity of the apoptotic area. Regenerating earthworms have decreased pattern recognition receptors (PRRs) (e.g., TLR, except for scavenger receptor) and antimicrobial peptides (AMPs) (e.g., lysenin) mRNA patterns compared to intact earthworms. In contrast, at the protein level, mirroring regulation of lysenins became evident. Experimental coelomocyte depletion caused significantly impaired cell divisions and blastema formation during anterior and posterior regeneration. These obtained novel data allow us to gain insight into the intricate interactions of regeneration and invertebrate innate immunity.


Assuntos
Imunidade Inata , Oligoquetos/fisiologia , Regeneração , Ferimentos e Lesões , Animais , Apoptose , Proliferação de Células , Regulação da Expressão Gênica , Oligoquetos/genética , Oligoquetos/imunologia , Toxinas Biológicas
9.
Int J Biol Macromol ; 173: 541-553, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33493562

RESUMO

Tissue regeneration and wound healing are still serious clinical complications globally and lack satisfactory cures. Inspired by the impressive regeneration ability of the post-injury earthworms and their widely accepted medicinal properties, we screened and identified a novel collagen-like peptide from the amputated earthworms using high-throughput techniques, including transcriptomics, proteomics, and mass spectrum. The identified collagen-like peptide col4a1 was cloned and expressed to comprehensively investigate the wound healing effect and underlying mechanism. It exerted significant effects on wound healing both in vitro and in vivo, including enhanced viability, proliferation, migration of fibroblasts, granulation, and collagen deposition. Moreover, the col4a1 functioned via binding with integrin α2ß1 and upregulating the RAS/MAPK signaling pathway. This work demonstrates that the novel collagen-like peptide col4a1 obtained from the amputated earthworms enables enhanced wound healing and provides new opportunities for wound care.


Assuntos
Colágeno Tipo IV/genética , Colágeno Tipo IV/metabolismo , Perfilação da Expressão Gênica/métodos , Integrina alfa1beta1/metabolismo , Oligoquetos/fisiologia , Proteômica/métodos , Cicatrização/efeitos dos fármacos , Animais , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clonagem Molecular , Colágeno Tipo IV/farmacologia , Modelos Animais de Doenças , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Espectrometria de Massas , Camundongos , Células NIH 3T3 , Oligoquetos/genética , Oligoquetos/metabolismo , Análise de Sequência de RNA
10.
Ecotoxicol Environ Saf ; 211: 111916, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33485012

RESUMO

ZnO nanoparticles (ZnO-NPs) can reach soil in both deliberate and non-deliberate ways, which leads to contamination. Notwithstanding knowledge about ZnO-NPs impacts on earthworms inhabiting these soils is limited and gaps appear in the recovery of damaged functions after their migration to unpolluted environments. To estimate these impacts, earthworms (Eisenia andrei) were exposed to different concentrations of coated ZnO-NPs (20, 250, 500, 1000 mgZnkg-1) in an acidic agricultural soil (pH 5.4) for 28 days. Subsequently, earthworms were placed in the same unpolluted soil to study the depletion of Zn accumulated and the recovery potential of the affected functions for another 28-day period.In the exposure phase, ecotoxicological responses were dose-dependent. Mortality and growth were affected at 500 and 1000 mg kg- 1, and the reproduction was impaired from 250 mgZnkg- 1 compared to control (54% fecundity and 80% fertility reduction). Zn uptake increased with coated ZnO-NPs in soil but it did not exceed 163 mgZnkg- 1 earthworm. During the recovery period, the Zn in earthworms were similar to the control regardless of the initially Zn accumulated. Reproduction parameters returned to the control values in the animals pre-exposed to 250 mgZnkg- 1 as coated ZnO-NP. In the earthworms preexposed to the two highest doses, growth and fertility were stimulated compared to the control when placed in clean soil, but not fecundity. However, the total hatchlings number did not reach the control figures after 28 days, but probably would for in longer times, which would be key for maintaining earthworm populations.


Assuntos
Oligoquetos/fisiologia , Poluentes do Solo/análise , Óxido de Zinco/análise , Agricultura , Animais , Ecotoxicologia , Nanopartículas , Solo/química , Zinco
11.
Ecotoxicol Environ Saf ; 208: 111587, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396110

RESUMO

Metalaxyl and Metalaxyl-M are the fungicides that widely used in many countries. In this study, the environmental behaviors between metalaxyl and metalaxyl-M in Tubifex tubifex (T. tubifex) were quantitative analyzed by using a high performance liquid chromatography with photo-diode-array-detector (HPLC-DAD). Results demonstrated that there was no significant difference (p > 0.05) in the concentration of metalaxyl and metalaxyl-M in T. tubifex during the exposure process. However, the dissipation behaviors of metalaxyl and metalaxyl-M in T. tubifex were different (p < 0.05) during the non-exposure culture process. Meanwhile, the toxic effects were also evaluated by comparing the different influences of these two compounds on related physiological indicators, and functional enzyme activities. The survival rates of T. tubifex were 63.33 ± 15.28% (20 mg L-1), 63.33 ± 5.77% (200 mg L-1) treated with metalaxyl and were 50.00 ± 10.00% (20 mg L-1), 46.67 ± 11.55 (200 mg L-1) treated with metalaxyl-M at the non-exposure culture process. The autotomy rates were increased significantly compared with the initial in all treatments. Besides, the activities of CAT, SOD, and GST in T. tubifex were also inhibited by metalaxyl and metalaxyl-M treatments. Finally, the high-throughput transcriptome sequencing technology was applied to investigate the metabolic pathways of target analytes in T. tubifex, and results proved that the metabolic pathways associated with human diseases (such as viral myocarditis) were up-regulated expression for metalaxyl and metalaxyl-M treatments, and metalaxyl-M up-regulated more significantly. All the results demonstrated that metalaxyl-M had a higher toxicity than metalaxyl on T. tubifex.


Assuntos
Alanina/análogos & derivados , Fungicidas Industriais/toxicidade , Oligoquetos/fisiologia , Alanina/toxicidade , Animais , Cromatografia Líquida de Alta Pressão , Oligoquetos/efeitos dos fármacos
12.
Ecotoxicol Environ Saf ; 208: 111622, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396142

RESUMO

The continuous growth in global population since the beginning of the 20th century result in the necessity of food and energy provision favoring the intensive use of agricultural products such as pesticides. Although pesticides are important to prevent losses in the conventional chemically based agriculture, they frequently present side effects, which goes against agricultural production. The use of pesticides cause direct and indirect effects to soil organisms unbalancing essential soil processes (e.g. primary production, organic matter decomposition, nutrient cycling). Under tropical conditions, very little is known regarding the effects of pesticides to terrestrial organisms. Hence, the aim of the present study was to assess the ecotoxicological effects of the herbicide DMA® 806 BR (active ingredient: 2,4-D) and the insecticide Regent® 800 WG (active ingredient: fipronil), on terrestrial plant species (the dicot Raphanus sativus var. acanthioformis and the monocot Allium cepa), and soil invertebrates (the collembolan Folsomia candida and the enchytraeid Enchytraeus crypticus), using natural (NS) and artificial soils (TAS). For both pesticides, negative effects on non-target species were observed at concentrations lower than the doses recommended to prevent pests in sugarcane fields. For both soils, the dicot species was the most affected by the herbicide (R. sativus > A. cepa > F. candida > E. crypticus) and the collembolan species was the most affected by the insecticide (F. candida > E. crypticus = R. sativus = A. cepa). Although the order of the organisms' sensitivity for both pesticides was the same in both soils, results showed that the extent of the effects was soil dependent. Considering the ecologically relevant concentrations tested, and their severe effects to non-target organisms, it may be concluded that the use of fipronil and 2,4-D under recommended conditions may pose a risk to the terrestrial environment.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Praguicidas/toxicidade , Pirazóis/toxicidade , Saccharum/fisiologia , Poluentes do Solo/análise , Agricultura , Animais , Artrópodes/efeitos dos fármacos , Artrópodes/fisiologia , Ecotoxicologia , Inseticidas/toxicidade , Oligoquetos/efeitos dos fármacos , Oligoquetos/fisiologia , Solo/química
13.
J Morphol ; 282(1): 98-114, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33074563

RESUMO

Ovaries of Haplotaxis sp. were studied in active and nonactive states, that is, in a sexually mature specimen and in specimens outside of the reproductive period. Two pairs of ovaries were found in segments XI and XII. Especially in the nonactive state, they were in close contact with copulatory glands. Each ovary was composed of germ cells interconnected with syncytial cysts, which were enveloped by a layer of somatic cells. Within cysts each germ cell had one ring canal connecting it to the common anuclear cytoplasmic mass called a cytophore. During oogenesis clustering germ cells differentiated into nurse cells and oocytes; thus, the oogenesis was recognized as meroistic. Vitellogenic oocytes were detached from the ovaries and continued yolk absorption within the body cavity. Because recent studies have shown the variety of ovaries and germ line cyst organization in clitellates and suggest their evolutionary conservatism at the family or subfamily level, the data presented here can be valid in understanding the phylogenetic relationships among Clitellata. In this context, ovaries found in Haplotaxis sp. resembled those of the "Tubifex" type. "Tubifex" ovaries are characteristic for numerous microdrile taxa (tubificines, limnodriloidines, propappids, lumbriculids, and leech-like branchiobdellids) and can be regarded as the primary character for these Clitellata in which germ-line cysts are formed during early oogenesis. As the family Haplotaxidae is currently considered to be paraphyletic and the species studied here belongs to Haplotaxidae sensu stricto, our results support the close relationship of Haplotaxidae sensu stricto to the clade consisting of Lumbriculidae, Branchiobdellida, and Hirudinida, in which lumbriculids are sister to the latter two.


Assuntos
Oligoquetos/fisiologia , Oogênese/fisiologia , Ovário/anatomia & histologia , Ovário/fisiologia , Animais , Feminino , Células Germinativas/citologia , Oligoquetos/ultraestrutura , Oócitos/citologia , Oócitos/ultraestrutura , Ovário/ultraestrutura , Filogenia
14.
Ecotoxicol Environ Saf ; 208: 111425, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33068978

RESUMO

Hermaphroditic lumbricid Eisenia sp. earthworms are ubiquitous and highly resistant to a variety of environmental stressors, including heavy metals. Among the progeny of laboratory mated inter-specific pairs of Eisenia fetida (Ea) and Eisenia andrei (Ef) there are fertile Ha hybrids derived from Ea ova fertilized by Ef spermatozoa and very rare sterile Hf hybrids from Ef ova fertilized by Ea spermatozoa. The aim of the first part of the experiment was to compare the life traits and whole body accumulation of cadmium in adult earthworms from genetically defined Ea, Ef and their hybrids (Ha) exposed for four weeks to commercial soil either unpolluted (control) or cadmium-spiked leading to moderate (M) or high (H) soil pollution (M = 425 and H = 835 mg kg-1 dry soil weight). Such exposure impaired cocoon production but not affected earthworm viability despite the massive Cd bioaccumulation in the whole earthworm bodies reaching at M and H groups 316-454, 203-338, 114-253, and 377-309 mg kg-1 dry body weights of Ea, Ef1, Ef2, and Ha, respectively, surprisingly reaching maximum accumulation quantities in hybrids. The second part of the experiment aimed to investigate cadmium-related defense mechanisms at transcriptomic level in coelomocytes non-invasively extruded from coelomic cavities of the new sets of Ea, Ef, Ha, and Hf earthworms exposed to Cd in microcosms for 0 days (control), 2 days, and 7 days (M = 425 mg kg-1). Expression level of stress-induced Cd-metallothionein (mt) and superoxide dismutase (sod) were gradually up-regulated, while the immune-connected lysenin (lys) was rapidly down-regulated; the expression of glutathione S-transferase (gst) and phytochelatin synthase (pcs) remained unaffected. Mt and sod gene up-regulation and lys gene down-regulation were especially pronounced in Ea-derived hybrids. In sum, capacity of cadmium bioaccumulation and detoxification mechanisms is more efficient in interspecific hybrids than in the pure Ea and Ef species.


Assuntos
Cádmio/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Aminoaciltransferases , Animais , Cádmio/metabolismo , Fertilidade , Fertilização , Glutationa Transferase/metabolismo , Masculino , Metalotioneína/metabolismo , Metais Pesados/metabolismo , Oligoquetos/metabolismo , Fenótipo , Reprodução , Solo , Poluentes do Solo/metabolismo , Especificidade da Espécie , Superóxido Dismutase/metabolismo
15.
Ecotoxicol Environ Saf ; 208: 111462, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33069946

RESUMO

The co-existence of organic pollutants and nanoparticles in the environment may lead to combined biological effects. The joint toxicity of pollutants and nanoparticles has been receiving increasing attention from researchers, but few studies have focused on soil biota due to the complexity of soil matrices. This study investigated the effects of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) at 0, 5, and 25 mg/kg and nanoparticulate TiO2 (nTiO2) at 0, 500, and 2500 mg/kg in a 3 × 3 factorial arrangement of treatments for 28 days (d) on Eisenia fetida (earthworm). Compared with the control group (the 0 mg/kg TDCIPP + 0 mg/kg nTiO2 treatment), all other single (TDCIPP or nTiO2) and binary (TDCIPP + nTiO2) treatments except for the single 500 mg/kg nTiO2 treatment significantly reduced the weight gain rate of E. fetida. The binary treatments had significantly greater such effect than their corresponding single treatments, exhibiting a synergistic toxicity between TDCIPP and nTiO2 on the growth of E. fetida. Since TDCIPP and nTiO2 had no significant effect on their concentrations in the soil or in E. fetida during binary exposure, the synergistic toxicity could be a result of the superimposition of the toxicity pathways of TDCIPP and nTiO2. Transcriptomic analysis of E. fetida intestinal region revealed that exposure to 25 mg/kg TDCIPP or 2500 mg/kg nTiO2 affected nutrient-related or cell apoptosis and DNA damage related genes, respectively; their co-exposure greatly inhibited genes related to nutrient digestion and absorption, while causing abnormal transcription of genes related to the development and maintenance of E. fetida's muscles, leading to synergistic toxicity. These findings provide new insights into the environmental risks of organophosphorus flame retardants, nanoparticles, and their co-exposure.


Assuntos
Poluentes Ambientais/toxicidade , Nanopartículas/toxicidade , Oligoquetos/fisiologia , Compostos Organofosforados/toxicidade , Titânio/toxicidade , Animais , Apoptose/efeitos dos fármacos , Retardadores de Chama/toxicidade , Oligoquetos/efeitos dos fármacos , Fosfatos/farmacologia , Solo
16.
Artigo em Inglês | MEDLINE | ID: mdl-33022380

RESUMO

The present study was assessed to determine the in vivo toxic effects of a cationic surfactant, cetylpyridinium chloride (CPC), and an anionic surfactant, sodium dodecyl sulfate (SDS) in terms of oxidative stress biomarkers in benthic oligochaete worm Tubifex tubifex for 14 days. The investigation demonstrated that sublethal concentrations of CPC (0.0213, and 0.0639 mg L-1) and SDS (1.094 and 3.092 mg L-1)induced paramount alterations in the oxidative stress enzymes in Tubifex tubifex. Superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH), and glutathione peroxidase (GPx) exhibited an initial notable increase in their activities in the surfactants exposed worms at 1d and 7d of exposure period followed by consequential reduction at 14d exposure period with respect to control, while catalase (CAT) and malondialdehyde (MDA) activities markedly incremented gradually throughout the exposure periods. Through the construction of the correlation matrix and integrated biomarker response (IBR), the effects of CPC and SDS on Tubifex tubifex were distinguished. These results indicate that exposure to these cationic and anionic surfactants modulates the levels of oxidative stress enzymes in Tubifex tubifex.


Assuntos
Cetilpiridínio/farmacologia , Oligoquetos/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Dodecilsulfato de Sódio/farmacologia , Tensoativos/farmacologia , Animais , Ânions/química , Biomarcadores/metabolismo , Catalase/metabolismo , Cátions/química , Glutationa/metabolismo , Glutationa Transferase/metabolismo , Metalotioneína/metabolismo , Oligoquetos/metabolismo , Oligoquetos/fisiologia , Dodecilsulfato de Sódio/química , Superóxido Dismutase/metabolismo , Tensoativos/química
17.
Biomech Model Mechanobiol ; 20(1): 5-30, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32651774

RESUMO

A continuous model for the peristaltic locomotion of compressible and incompressible rod-like bodies is presented. Using Green and Naghdi's theory of a directed rod, incompressibility is enforced as an internal constraint. A discussion on muscle actuation models for a single continuum is included. The resulting theory is demonstrated in a simulation of a soft-robotic device. In addition, a calibration of parameters is performed and the incompressible rod is validated against a biomimetic model of earthworm locomotion.


Assuntos
Locomoção/fisiologia , Modelos Biológicos , Oligoquetos/fisiologia , Peristaltismo/fisiologia , Robótica , Animais , Fenômenos Biomecânicos , Biomimética , Simulação por Computador , Pressão Hidrostática , Reprodutibilidade dos Testes
18.
Integr Zool ; 16(2): 255-269, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33190356

RESUMO

The ingestion of organic and mineral materials by earthworms is a prominent functional role that has profound consequences for the decomposition and stabilization of soil organic matter. To investigate the litter consumption of the African nightcrawler earthworm Eudrilus eugeniae under different tropical conditions, we used DNA barcoding to identify specimens of E. eugeniae collected from sites across the Adamawa region in Cameroon, and studied the influence of habitat suitability (soil properties), soil moisture, litter type, and population density on litter consumption. A total of four litter consumption experiments were carried out using soils collected from refuse disposal sites, agricultural lands, and savannahs dominated by the Mexican sunflower Tithonia diversifolia. The results revealed that litter consumption significantly increased in the refuse disposal and agricultural soils as opposed to the Mexican sunflower (T. diversifolia) soil, a cow dung enriched substrate, and a sterile soil horizon from the savannah (P < 0.05). The optimum moistures for litter consumption were between 24% and 50%. Litter type did not affect the consumption rate of the earthworms (P > 0.05). We observed a general positive density-dependent consumption with litter mass loss increasing with increasing density. Our results suggest that E. eugeniae has a strong direct effect on the decomposition of plant materials than expected from previous estimations, and that litter consumption rates are determined by several habitat components and population density.


Assuntos
Ecossistema , Oligoquetos/fisiologia , Solo/química , Solo/classificação , Animais , Camarões , Código de Barras de DNA Taxonômico , Esterco , Oligoquetos/genética , Densidade Demográfica , Eliminação de Resíduos , Tithonia , Clima Tropical
19.
Ecotoxicol Environ Saf ; 207: 111375, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32987189

RESUMO

Freshwater sediments are a repository of microplastics (MPs) resulting from inland anthropogenic activities. Benthic invertebrates, particularly endobenthic sediment-ingesting species such as the annelid Lumbriculus variegatus (blackworm), are commonly found in contaminated sediments where they likely find and ingest MPs. In the present study, L. variegatus was exposed to concentrations between 0.51 and 20 g kg-1 dry sediment of four size-classes of irregularly-shaped polyethylene MPs (PE-MPs; size-class A: 32-63, B: 63-125, C: 125-250 and D: 250-500 µm) for 48 h to assess their sub-cellular responses to particles ingested, and for 28 days to determine chronic effects on worm's reproduction and biomass. After the short-term exposure (48 h), number of PE-MPs in blackworms' gut were related to MPs concentration in the sediment. In general, PE-MPs ingestion by blackworms induced depletion of their energy reserves (e.g., sugars in all size classes and lipids in the size-classes of PE-MPs > 125 µm), concomitant with the activation of antioxidant and detoxification mechanisms (increased level of total glutathione in all size-classes, and increased glutathione-S-transferase activity in PE-MPs > 250 µm), preventing lipid peroxidation. In addition, it was observed a reduction of aerobic energy production (decreased activity of the electron transport system) and a slight increase in neurotransmission (cholinesterase activity). After a long-term exposure (28 d), the presence and ingestion of PE-MPs did not affect reproduction and biomass of L. variegatus. The activation and efficiency of the antioxidant and detoxification mechanisms allied with the anatomy and physiology of L. variegatus, its feeding strategy and potentially dynamic ingestion/egestion capacity seem to be key features preventing MP deleterious effects under short- and chronic-exposures. Considering the MPs levels reported for freshwater sediments, and despite evidence of MPs ingestion and some sub-organismal effects, our results suggest no adverse impacts of PE-MPs contamination on L. variegatus populations fitness. This study applies an integrative approach in which data concerning the ingestion of different sized MPs and subsequent sub-cellular and apical responses are delivered, raising knowledge on endobenthic invertebrates' strategies to potentially overcome MP toxicity in field contaminated sites.


Assuntos
Microplásticos/toxicidade , Oligoquetos/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Ingestão de Alimentos , Água Doce , Sedimentos Geológicos , Oligoquetos/efeitos dos fármacos , Plásticos/toxicidade , Polietileno , Reprodução/efeitos dos fármacos
20.
Ecotoxicol Environ Saf ; 207: 111547, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254406

RESUMO

In this paper, earthworms (Eisenia fetida) were exposed to sublethal doses of dichlorvos (spiked concentration of 0.1, 1.0, 10 mg/kg) in soil for 14 days, the metabolomics and activities of cytochrome P450 (CYP) isoenzymes (CYP1A2, CYP2C9 and CYP3A4) of earthworms were analyzed aiming to identify sensitive biomarkers and reveal possible mode of toxic action. The results showed that CYP1A2 and CYP2C9 activity appeared to be more sensitive than CYP3A4 activity in response to dichlorvos, and that metabolic responses based on the metabolomics depended on both of the length of exposure and exposure dose. Malate, ornithine, glucose, inosine, myo-inositol and some amino acids (glutamine, tryptophan, phenylalanine, tyrosine, leucine, histidine, glutamate, lysine) and CYP isozenzymes may be biomarkers to reveal the toxic effect of dichlorvos on earthworms. Compared to controls, when dichlorvos dose reached 1.0 and 10 mg/kg on day 14, glucose and ornithine increased significantly, malate and some amino acids (glutamine, tryptophan, phenylalanine, tyrosine, leucine) decreased significantly, and activities of CYP1A2 and CYP2C9 were inhibited significantly. The current results suggested that 1.0 and 10 mg/kg dichlorvos for 14 days of exposure blocked energy metabolism, disordered Krebs cycle, interfered amino acids metabolism and evoked toxic effects on earthworms.


Assuntos
Diclorvós/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Animais , Biomarcadores/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP1A2/farmacologia , Citocromo P-450 CYP3A/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Isoenzimas/metabolismo , Metabolômica/métodos , Oligoquetos/efeitos dos fármacos , Solo/química , Poluentes do Solo/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...