Abstract

The Angiotensin II receptor antagonists (ARA II) are primarily eliminated in domestic effluent and commonly observed in conventional wastewater from sewage plants and rivers that receive run-off from treatment facilities. Nevertheless, ARA II medications show low elimination efficiencies in municipal wastewater treatment facilities, suggesting possible harmful effects for aquatic life. In the current study, individual and combined treatments (187.5-900 ng/L) of two ARA II, losartan and irbesartan, were applied for one month to marine nematodes. The results highlighted significant decreases in the relative abundance of epistratum feeding groups, characterized by a spiral amphid shape, elongated/filiform tail shape, and c-p3 life history type, especially in the assemblages exposed to the highest concentrations and mixtures. The results also emphasized that losartan is more toxic compared to irbesartan, with antagonism interactions between both drugs. Another conclusion was that Longicyatholaimus longicaudatus and Marylynnia puncticaudata were sensitive to ARA II contamination, whereas the genera Theristus, Halalaimus, and Sabatieria species were tolerant.

Abstract

Miglustat (MGU) and migalastat (MLA) are commonly used to treat two rare lysosomal disorders, namely Gaucher's and Fabry's diseases, but lately suggested as cures for the COVID-19 disease. The impact of both drugs on meiobenthic nematodes was tested in laboratory conditions for 15 and 30 days. As such, nine treatments were used, targeting nematodes collected from Jeddah coasts (Saudi Arabia), and based on a control treatment and two concentrations (1.45 and 2.9 mg.l-1) of MGU and MLA, applied separately or combined. The findings showed a decline in nematode abundance in all treatments, particularly within the MGU2/MLA2 community. Moreover, the results obtained showed that Daptonema aegypticum was a positive bioindicative species for MGU, and D. oxycerca and Longicyatholaimus longicaudatus were positive bioindicative taxa for MLA. Moreover, when combined, the mixtures induced multifaceted effects in the functional traits composition, revealing complex synergic interactions at the community level.

Abstract

Miglustat (MGU) and migalastat (MLA) are commonly used to treat two rare lysosomal disorders, namely Gaucher's and Fabry's diseases, but lately suggested as cures for the COVID-19 disease. The impact of both drugs on meiobenthic nematodes was tested in laboratory conditions for 15 and 30 days. As such, nine treatments were used, targeting nematodes collected from Jeddah coasts (Saudi Arabia), and based on a control treatment and two concentrations (1.45 and 2.9 mg.l−1) of MGU and MLA, applied separately or combined. The findings showed a decline in nematode abundance in all treatments, particularly within the MGU2/MLA2 community. Moreover, the results obtained showed that Daptonema aegypticum was a positive bioindicative species for MGU, and D. oxycerca and Longicyatholaimus longicaudatus were positive bioindicative taxa for MLA. Moreover, when combined, the mixtures induced multifaceted effects in the functional traits composition, revealing complex synergic interactions at the community level. © 2024

Abstract

Introduction The current experiment investigated the multifaceted effects induced by microplastics and the statin Lipitor on marine benthic nematodes.Methods The nematodes were exposed to a single polystyrene and polyvinyl chlorides (both at 1 mg.kg-1 Dry Weight) and two Lipitor concentrations (0.1 and 1 mg.l-1), as well as to a mixture of both types of pollutants, for 30 days.Results The results highlighted a significant decrease in the abundance, individual biomass, and diversity of nematodes directly with the addition of polyvinyl chlorides and/or Lipitor. These treatments induced a greater mortality rate among microvores and diatom feeders compared to other feeding types of nematodes.Discussion The nematofauna underwent a strong restructuring phase following exposure to microplastics and Lipitor when added alone, leading to the disappearance of sensitive species and their replacement by more tolerant taxa. The toxicity of Lipitor is attenuated by the physical bonding with polystyrene when added to a mixture and has no negative effect on marine nematode species.

Abstract

PBDE-47, with lipophilic properties, was found in mussels, clams, and fish where it causes developmental issues, and endocrine and immune disruptions. The current study investigated the effects of PBDE-47 (0.1, 1, and 10 mu g. l- 1 ) on the clams Ruditapes decussatus and the nematode Metoncholaimus pristiurus. This flame retardant reduced CAT and GST activities in R. decussatus after only 2 days. The AChE activity was similar after 2 days but decreased after 7 days in the digestive gland. In gills, a decrease in AChE activities was observed for both time slots. The clearance rates increased following exposure for 2 days but decreased after one week. The exposure of M. pristiurus to PBDE-47 was accompanied by an increase in CAT and GST activities and a decrease in that of AChE. The microbial descriptors supported the obtained results for this nematode. Finally, the computational analyses supported the ecotoxicity of PBDE-47 for both invertebrate species.

Abstract

Abstract

The aquatic subterranean ecosystems represent research frontiers for ecology and conservation biology. The aquatic subterranean fauna and associated microorganisms are organised in food webs that are essential in the nutrients cycling and energy fluxes within habitats generally characterised by low resources. However, the knowledge of how these trophic networks are structured and conditioned by the interaction with surface ecosystems is scarce. Traditionally, subterranean aquatic food webs were regarded as simple and truncated because of low species diversity and abundance compared to surface. The current review provides an updated description of aquatic subterranean food webs, based on the latest findings from various types of habitats: cave streams, the hyporheic zone and phreatic aquifers, with the general conclusion that such trophic networks are much more complex and dynamic as historically believed. The energylimitation hypothesis and the bottom-up forces are increasingly recognised as the main structuring agents of the aquatic subterranean trophic networks. It is predicted that the bottom-up forces are generated by two interconnected factors: nutrients availability in water and quantity, quality and the types (i.e. surface derived photosynthetic and detrital, in some cases mixed with in situ chemosynthetically based organic matter) of basal energy input. Further recommendations for the integration of groundwater research into the current overarching concepts of surface ecology are made, given this field of science remains currently rather descriptive and less hypothesis-driven.

Abstract

Cadmium (Cd) is considered as one of the most highly toxic heavy metal that is released into the environment on a large scale, and its concentrations in water have significantly increased as a result of human activities. In particular, contamination of rivers and drinking water may easily occur, especially in locations close to industry or mines. In this study, we examined the impact of Cd exposure on the body wall of the freshwater leech Limnatis nilotica at concentrations of 100, 200, and 300 µg/l. The findings showed that the exposure caused histopathological changes as well as oxidative stress (increased malondialdehyde concentrations (MDA)) and changes in antioxidant activity (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (Gpx)). In fact, numerous histological changes were observed, such as cuticle deterioration, a marked increase in the number of secretory cells, increased mucus production, vacuolization of the epithelium, altered epithelial cell borders, and mucus cell hyperplasia. The histological results are consistent with the biochemical findings because we found that MDA levels significantly increased in a dose-dependent manner. Additionally, the Cd exposure disrupted the levels of the antioxidant levels. Indeed, SOD, CAT, and Gpx activities were increased in the group treated with the lower dose (100 g/l), whereas their levels dramatically decreased at higher Cd doses (200 and 300 g/l). Therefore, the presence of this heavy metal in freshwater habitats may have severe ecological risks that may lead to leech aquatic habitat destruction and fragmentation. © 2023, Universita degli Studi di Modena e Reggio Emilia. All rights reserved.

Abstract

The present study examined the histopathological changes and some parameters of oxidative stress in the testes of the freshwater leech Limnatis nilotica, following their exposure to 50 mu g l(-1) of cadmium (Cd). The protective effects of salicylic acid (SA) in mitigating Cd-induced oxidative and histopathological injury were also investigated. We found that Cd exposure caused several histopathological changes in leech testes, such as vacuolisation of spermatogenic cysts which were strongly destroyed and disorganised. Biochemical study showed oxidative stress damage marked by a substantial increase in malondialdehyde and hydrogen peroxidase levels as well as disturbance in the activity of the leech antioxidant system. Interestingly, the testes from the Cd and SA leech-exposed group exhibited increased enzymatic and nonenzymatic antioxidant mechanism defenses, including superoxide dismutase, catalase, glutathione peroxidase, glutathione, oxidized glutathione, thiols, and ascorbic acid, in comparison with the testes of leeches exposed to Cd alone. Thus, SA supplementation considerably attenuated the histopathological lesions induced by Cd exposure, thereby restoring the normal appearance of the testes. In summary, the findings of this study indicate that SA treatment ameliorated the testicular histopathological and oxidative stress-induced damages caused by exposure to Cd through enhancing the antioxidant defense system.

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are toxic for humans and marine fauna alike. The current study assessed the impact of PAHs on the migratory behaviour of meiobenthic nematodes collected from the Bizerte lagoon, Tunisia. The experiment lasted for 15 days and was carried in open microcosms, which comprised a lower, contaminated and an upper, uncontaminated compartment. Three treatments were used, for each of them an untreated control was set up: sediment contaminated with chrysene (116 ng g(-1) dry weight (DW), with phenanthrene (116 ng g(-1) DW) and a mixture of both. The results showed a significant decrease in diversty and abundance in the lower, contaminated compartments compared to the upper zones. The results also highlighted that under an increased stress some species progressively increased in number, these were considered PAH-tolerant species such as Odontophora villoti, some others had an occasionally increased in number were consid-ered as opportunistic species, such as Paracomesoma dubium and the species that showed a progressive decreased in number, such as Metoncholaimus pristiurus and Steineria sp., Terschellingia. longicaudata, and Oncholaimellus sp. were classified as PAH-sensitive. Moreover, an increase in the activity of biochemical biomarkers was observed following the exposure of males and gravid females of T. longicaudata to 29, 58 and 87 ng g(-1) DW of chrysene and phenanthrene paralleled by a higher vulnerability of the latter demographic category. Besides, a significant decrease in fertility of females and an increase in pharyngeal sucking power were observed for both types of PAHs considered. The sex ratio was also significantly imbalanced in the favor of males, which suggest that chrysene and phenanthrene affect also the hormone system of T. longicaudata. The high affinities of these PAHs and their molecular interactions with both germ line development protein 3 (GLD-3) and sex-determining protein (SDP) may justify these results and explain the toxicokinetic attributes.