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1.
Environ Pollut ; 286: 117300, 2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33971469

RESUMO

An experimental study was carried out to determine the effects of the enrichment of sediments by endocrine perturbators on free-living nematodes from the Ghar El Melh lagoon, Tunisia. For 30 days, four concentrations of Estradiol Benzoate (hereafter EB) (0.43, 4.3, 8.6 and 12.9 ng l-1). The average nematode abundances showed a significant increase after the introduction of EB in their close environment. In contrast, the taxonomic examination has shown a decrease in species diversity of nematodes. The ordination of treatments according to the nMDS showed a clear structural separation of the enriched replicates with EB from controls based on species lists, in particular for concentrations EB3 and EB4. Indeed, under such conditions, the nematofauna exhibited a more remarkable presence of a new record for Science Theristus n. sp. and a decrease in relative abundances of Paracomesoma dubium. On feeding level, a predominance of non-selective deposit-feeders and a decline in proportions of epistrate feeders and carnivorous omnivores was observed with increasing concentrations of EB. Furthermore, in treated replicates with EB, females discernibly showed an increase compared to controls. Overall, EB affect significantly features of meiobenthic nematodes starting from the concentration of 4.3 ng l-1.

2.
Mar Pollut Bull ; 157: 111375, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658716

RESUMO

At the end of March 2020, ivermectin was confirmed as a drug for COVID-19 treatment. A significant amount of ivermectin could deposit into sediments of the semi-closed Mediterranean Sea, where three European COVID-19 epicenters are located: Italy, Spain, and France. Meiobenthic nematodes were exposed to three ivermectin doses (1.8 ng.g-1, 9 ng.g-1, and 18 ng.g-1) for 10 days. Ivermectin caused a great reduction in abundance. However, the diversity indices decreased only at high doses. Ivermectin disadvantaged the 1B-Cr-Id functional type (non-selective deposit feeders and nematodes with circular or indistinct amphids) and benefited the 2A-REL-Sp type (epistrate feeders and nematodes with rounded or elongated loop amphids). Thus, Trophic Diversity and Amphideal Diversity index values increased with sedimentary ivermectin enrichment. Large amphideal foveas were more efficient for 2A-REL-Sp nematodes to avoid ivermectin. The responses of the functional type 2A-REL-Sp and corresponding taxa predict post-COVID-19 environmental concerns and the bioaccumulation of ivermectin in seafoods.


Assuntos
Antivirais/toxicidade , Infecções por Coronavirus , Ivermectina , Nematoides , Pandemias , Pneumonia Viral , Animais , Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , França , Humanos , Itália , Ivermectina/toxicidade , Mar Mediterrâneo , Espanha
3.
Environ Pollut ; 262: 114350, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32197121

RESUMO

A laboratory bioassay was conducted to investigate the ecotoxicity of a chromium-enriched superfood, Spirulina platensis, on the meiofauna collected from the Ghar El Melh lagoon, Tunisia. After 1 month of exposure, the abundances of meiobenthic taxa and the taxonomic and morpho-functional diversity of nematodes showed significant differences between the Spirulina and Spirulina + chromium groups. The nematodes were more tolerant of all types of stressors compared to harpacticoids, polychaetes, and oligochaetes, and the lowest taxonomic and morpho-functional diversity of nematodes was observed in the highest sedimentary concentration of S. platensis (50% DW). The mixed treatments may have been richer in micro-habitats and subject to low selective pressure, thereby hosting nematodes with a wide range of adaptations. The responses of the nematode species differed depending on their functional traits. Spirulina enriched with chromium induced two responses for the same feeding group: high toxicity for Daptonema fallax and low toxicity for two Theristus species (T. flevensis and T. modicus). The ecotoxicity of the Spirulina/chromium mixtures were lower than that of Spirulina alone, suggesting mutual neutralization between these two elements. The association between functional traits and taxonomic diversity showed that the effects of the mixtures were not additive and that one of the stressors camouflaged the effect of the other. Our findings should encourage the commercialization of chromium-enriched S. platensis owing to its lower ecotoxicity than Spirulina alone.


Assuntos
Nematoides , Spirulina , Animais , Cromo , Ecossistema , Tunísia
4.
Ecotoxicology ; 25(6): 1160-9, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27230096

RESUMO

Trophic structure of free living nematode from Bizerte lagoon was tested by a microcosmic study after 30 days of exposure with 5 increasing doses of pharmaceutical penicillin G (D1: 3 mg L(-1), D2: 30 mg L(-1), D3: 300 mg L(-1), D4: 600 mg L(-1), D5: 700 mg L(-1)). Results showed significant differences between nematode assemblages from undisturbed controls and those from penicillin G treatments. Selective deposit-feeders (1A) or nonselective deposit-feeders (1B), very abundant in the control microcosm, were significantly affected and their dominance declined significantly. Epistrate feeders (2A) were significantly gradual increase for all microcosms treated with penicillin G, appeared to be more tolerant to the antibiotic and to take advantage of the growing scarcity of other trophic groups. Compared to the control microcosms, omnivorous-carnivorous (2B) was found to be higher in all treated microcosms, with the exception of those treated with D5. Trophic index (Σθ(2)) was significantly reduced in all microcosms treated whereas trophic ratio 1B/2A appears to be insignificant.


Assuntos
Antibacterianos/toxicidade , Nematoides/fisiologia , Penicilina G/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Cadeia Alimentar , Sedimentos Geológicos/química , Nematoides/efeitos dos fármacos , Testes de Toxicidade
5.
Environ Toxicol Pharmacol ; 40(1): 215-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26148743

RESUMO

A microcosm experiment was conducted to examine the effects of the pharmaceutical (penicillin G) on free living nematode communities of a Tunisian coastal zone (South-Western Mediterranean Sea). Sediments were contaminated with five penicillin G dose [D1 (3 mgL(-1)), D2 (30 mgL(-1)), D3 (300 mgL(-1)), D4 (600 mgL(-1)), D5 (700 mgL(-1))], and effects were examined after 30 days. Results showed significant differences between nematode assemblages from undisturbed controls and those from penicillin G treatments. Most univariate measures, including diversity (H'), species richness (d), equitability (J) and number of species (S) decreased significantly with increasing level of the antibiotic contamination. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the penicillin treatments were varied: Kraspedonema octogoniata and Paracomesoma dubium were eliminated at all the antibiotic doses tested and seemed to be intolerant species to penicillin G contamination; Oncholaimus campylocercoides although survived even the highest dose D5, showed definite reduction in its abundance and may be classified as "opportunistic" species at this dose, whereas, Nannolaimoides decoratus which showed a positive response with an increase in density even at highest concentration of contaminant, seems to be "penicillin G resistant" species.


Assuntos
Nematoides/efeitos dos fármacos , Penicilina G/metabolismo , Preparações Farmacêuticas/metabolismo , Animais , Nematoides/metabolismo
6.
Environ Sci Pollut Res Int ; 19(3): 646-55, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21909790

RESUMO

INTRODUCTION: We conducted a yearly polluted-reference sampling to assess the effects of petroleum pollution on life cycle characteristics of the meiobenthic nematode Odontophora villoti. Samples were taken every 15 days between 26 November 2004 and 25 November 2005 from two beaches of Bizerte bay (Tunisia), Rimel and Tunisian Refining Industries Company (TRIC). The latter site is located in front of the "Tunisian Refining Industries Company" runoff. DISCUSSION: When compared to the reference site, the mean body dimensions of O. villoti from the impacted site were significantly lower. The small size of affected nematodes was represented both by the length and width as a function of the life stage. It was also established that changes in lengths of body parts during molts were different between the two study sites. The low availability of oxygen from April to August seems to prevent the formation of embryos of O. villoti. Thus, two annual reproductive cycles with different durations were observed in Rimel and TRIC. Under stress, juvenile phase and egg production were generally shorter. Globally, the impact of petroleum pollution on O. villoti was expressed by a short egg-to-egg development time. CONCLUSION: Our study assessed the usefulness of life cycle characteristics (biometry and life stage durations) of O. villoti in biomonitoring, and the results are generally consistent suggesting that this species may be considered as an efficient bioindicator.


Assuntos
Exposição Ambiental , Monitoramento Ambiental/métodos , Estágios do Ciclo de Vida/efeitos dos fármacos , Nematoides/efeitos dos fármacos , Nematoides/crescimento & desenvolvimento , Poluição por Petróleo/efeitos adversos , Poluentes Químicos da Água/toxicidade , Animais , Biometria , Tamanho Corporal/efeitos dos fármacos , Indústrias Extrativas e de Processamento , Feminino , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Masculino , Mar Mediterrâneo , Muda/efeitos dos fármacos , Oviposição/efeitos dos fármacos , Reprodução , Estações do Ano , Fatores de Tempo , Tunísia , Poluentes Químicos da Água/análise
7.
Biol Trace Elem Res ; 144(1-3): 790-803, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21455706

RESUMO

Free-living nematodes are the most abundant taxa among the meiobenthos and the predominant prey for bottom-feeding fishes. They are able to accumulate toxicants from sediments which explain their use in this study as possible tools in nutritional quality assessment of fishes. Nematodes from sediments of Ghar El Melh lagoon (Tunisia) were subjected to cobalt and/or zinc enrichment in a microcosm experiment for 30 days. Three levels (low, medium, and high) of each treatment were used. Nematode abundance and diversity significantly decreased, and the taxonomic structure was altered. Results from multivariate analyses of the species abundance data revealed that all treatments were significantly different from the control. Both univariate and multivariate analyses of the data showed that the differential response occurred in all treatments, but the assemblages from microcosms contaminated with zinc alone were much more negatively affected compared with those exposed to cobalt alone. The presence of cobalt simultaneously with zinc seems to reduce its impact on nematode species composition. Such a result is suggestive of antagonistic interactions between these two metals. The responses of nematode species to the cobalt and zinc treatments were varied. Oncholaimellus mediterraneus, Oncholaimus campylocercoides, and Neochromadora trichophora were significantly affected with cobalt contamination but, they were not eliminated. Exposed to zinc, Hypodontolaimus colesi was eliminated and seemed to be an intolerant species versus this metal. Some of these species, "cobalt-sensitive" or "zinc-sensitive", were also affected by the metal combination even at low dose: O. mediterraneus, N. trichophora, and H. colesi. Differential sensitivity to cobalt and/or zinc may result in a subsequent competitive release of more tolerant species. A list of this kind of species was established to be used as a possible preventive tool versus contaminated fish. This was most evidently the case in Marylynnia stekhoveni and O. campylocercoides which increased at all doses of cobalt and zinc, respectively. These two resistant species have also the opportunity to dominate the nematode assemblage when the studied metals were added together. The level of health risk is probably higher for humans assimilating additional amount of cobalt and zinc, especially heavy smokers and/or patients using some medications including salts of these metals.


Assuntos
Cobalto/toxicidade , Sedimentos Geológicos/química , Nematoides/metabolismo , Zinco/toxicidade , Análise de Variância , Animais , Interpretação Estatística de Dados , Relação Dose-Resposta a Droga , Mar Mediterrâneo , Nematoides/classificação , População , Especificidade da Espécie , Tunísia
8.
Mar Pollut Bull ; 50(11): 1197-204, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15896812

RESUMO

Anthropogenic inputs of crude and refined petroleum hydrocarbons into the sea require knowledge of the effects of these contaminants on the receiving assemblages of organisms. A microcosm experiment was carried out to study the influence of diesel on a free living nematode community of a Tunisian lagoon. Sediments were contaminated by diesel that ranged in concentration from 0.5 to 20 mg diesel kg(-1) dry weight (dw), and effects were examined after 90 days. Gradual changes in community structure were revealed depending on the quantity of diesel administrated. In the medium (1 mg diesel kg(-1) and 5 mg diesel kg(-1) (dw)) and high (10 mg diesel kg(-1), 15 mg diesel kg(-1) and 20 mg kg(-1) (dw)) treated microcosms, most univariate measures, including diversity and species richness, decreased significantly with increasing level of diesel contamination whereas nematode assemblage from the low treated microcosm (0.5 mg diesel kg(-1) (dw)) remained unaffected. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the diesel treatments were varied: Chaetonema sp. was eliminated at all doses tested and seemed to be intolerant species to diesel contamination; Pomponema sp. and Oncholaimus campylocercoïdes were significantly affected at all diesel contamination levels but they were not eliminated, these species were categorized as "diesel-sensitive"; Hypodontolaimus colesi, Daptonema trabeculosum and Daptonema fallax which significantly increased respectively at 0.5, 1 and 5 mg diesel kg(-1) (dw) concentrations and appeared to be "opportunistic" species at these doses whereas Marylynnia stekhoveni which increased at all high doses (10, 15 and 20 mg diesel kg(-1) (dw)) seemed to be a "diesel-resistant" species.


Assuntos
Ecossistema , Poluentes Ambientais/análise , Gasolina/toxicidade , Sedimentos Geológicos/análise , Nematoides/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Poluentes Ambientais/toxicidade , Análise Multivariada , Especificidade da Espécie , Tunísia
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