Automated recognition and analysis of head thrashes behavior in C. elegans

Toxicity of additives present in conventional and biodegradable plastics on soil fauna: a case study of the root lesion nematode Pratylenchus neglectus

Plastic pollution in terrestrial environments is a growing concern, with an increasing focus on the impact of plastic additives on soil ecosystems. We evaluated the impact of additives from conventional plastics (ACP) and biodegradable plastics (ABP) on the soil nematode, Pratylenchus neglectus. The additives represented five functional classes (antioxidants, colourants, flame retardants, nucleating agents, and plasticisers). P. neglectus exhibited concentration-dependent mortality when exposed to the additives, with Tartrazine, an ABP colourant, inducing higher mortality compared to the conventional counterpart. No significant changes in the locomotory patterns of P. neglectus were observed, whereas oxidative stress significantly increased in response to all assistive treatments. Exposure to most of the additives resulted in a significant decline in nematode reproduction; ACPs generally caused more severe effects than ABPs. Our findings highlight a complexity in how plastic additives impact soil organisms and challenge the assumption that ABPs may be universally safer for ecosystems. The study emphasises the importance of conducting ecotoxicological assessments of specific ABPs on important species to inform the design of environmentally sustainable plastics. The results also suggest that P. neglectus could serve as a valuable sentinel organism for evaluating the ecological impacts of plastic pollution in soil.

Network Flow Method Integrates Skeleton Information for Multiple C. elegans Tracking

In order to solve the issues arising from collisions, this paper proposes a network flow method combined with skeleton information for multiple C. elegans tracking. In the intra-track stage, non-colliding C. elegans are identified and associated as trajectory fragments based on their motion and positional information, and colliding C. elegans are then segmented based on an improved skeleton algorithm and matched as trajectory fragments. Subsequently, the trajectory fragments are employed as vertices to construct a network flow model. The minimum-cost method is then utilized to solve the model, thereby obtaining the optimal solution for the multiple C. elegans trajectories. The proposed method was evaluated using video data of the C. elegans population at three distinct ages: L4, young adult, and D1. The experimental results demonstrate that the method proposed in this paper exhibits a MOTA between 0.86 and 0.92, and an MOTP between 0.78 and 0.83, which indicates that the proposed method can be employed in multiple C. elegans tracking. It is our hope that this method will prove beneficial to C. elegans laboratories, offering a novel approach to multiple C. elegans tracking.

Transcriptomic analysis reveals decreased expression of detoxification genes in Caenorhabditis elegans exposed to mepanipyrim and cyprodinil: Implications for multigenerational exposure effects

The broad-spectrum fungicides mepanipyrim (Mep) and cyprodinil (Cyp) have been reported to be used worldwide to control gray mold of fruit crops. Consequently, they are often detected in the water and food items. However, the impacts and potential mechanisms of these two pesticides on environmental organisms remain unclear. Utilizing Caenorhabditis elegans (C. elegans) as the model, the toxic effects and mechanisms were analyzed after Mep and Cyp exposure over four generations (P0-F3). The results showed that Mep and Cyp at concentrations over 0.1 µg/L affected the motility behavior, while 1.0 µg/L dosage and above inhibited the growth of C. elegans. In addition, multigenerational exposure could significantly impair both locomotion and development of C. elegans even at 0.01 µg/L dosage. Notably, constant exposure resulted in the function abnormalities of cholinergic, dopaminergic and GABAergic neurons, as well as the accumulation of ROS. Further transcriptome analysis showed reduced expression of 14 genes and 26 genes in xenobiotic metabolic pathway following Mep and Cyp exposure, respectively. The buildup of Mep/Cyp and ROS might have led to nerve impairment and behavioral abnormality. These findings enhanced understanding of the toxic effects of Mep and Cyp and provided insights into their eco-toxicological evaluation.

Chemotherapeutic Drug Delivery Nanoplatform Development: From Physicochemical to Preclinical Evaluation

Through this study, the synergistic behavior of small-molecular-weight, amphiphilic surfactant molecules and the triblock copolymer Pluronic 188 was extensively evaluated based on their ability to formulate nanocarriers with novel properties for the delivery of class II and IV (biopharmaceutical classification system) chemotherapeutic compounds. The combination of four different surfactants at multiple weight ratios and twelve initially formulated nanosystems resulted in four hybrid delivery platforms, which were further studied in terms of multiple physicochemical characteristics, as well as their stability in protein-rich media (fetal bovine serum/phosphate-buffer saline). Finally, we obtained a single final nanoformulation that exhibited a high loading capacity (%EE ≥ 75%) and a sustained drug release profile under physiological conditions (model drug methotrexate), without altering the original physicochemical characteristics of the carrier. With a mean hydrodynamic radius (Rh) of less than 70 nm, a polydispersity index of 0.219, and no protein complexation, the system is a suitable candidate for in vivo, intravenous, and/or intramuscular administration. The cytotoxicity and genotoxicity of both loaded and unloaded carriers were evaluated through the examination of the upregulation or downregulation of apoptosis-related pathways. Multiple conventional 2D and 3D spheroidal conformations were used for these assessments, including HEK293, HCT-116, and MCF-7 cell lines, the results of which stressed the safety and biocompatibility of the empty nanocarrier. Additionally, experiments on Caenorhabditis elegans were conducted to evaluate the system's in vivo toxicity, focusing on developmental stages, egg-laying behavior, and locomotion. Nanosystems studied in terms of chemotherapeutic encapsulation have mostly focused on the physiochemical aspect of the development of such novel delivery platforms, with only few exceptions proceeding step-by-step from cellular 2D to 3D to in vivo experimentation. The present study offers a holistic view of the behavior of such a novel system, advancing our understanding of the capabilities of polymeric/surfactant-based nanodelivery platforms.

The joint toxicity effect of glyphosate and cadmium in a concentration-dependent manner on nematode Caenorhabditis elegans

The co-occurrence of glyphosate (GPS), a commonly used organophosphorus herbicide, and cadmium (Cd), a neurotoxic metal, in agricultural environments prompts concerns about their combined toxic effects on ecosystems. This study explores the combined effects of GPS and Cd on the model organism Caenorhabditis elegans (C. elegans), to understand their cumulative effects in organismal living environments. We investigated the interaction between GPS and Cd over 24 hours using a comprehensive approach that included a variety of toxicity endpoints as well as the novel Automated Recognition and Statistics Tool (NCLE) for body bend measurement. Our data show a concentration-dependent interplay in which antagonistic effects at lower concentrations reduce phenotypic damage while synergistic effects emerge at higher concentrations, particularly at GPS's LC50. Transcriptome analysis under antagonistic conditions revealed significant downregulation of Cd toxicity-related genes and identified Y22D7AL.16, which has a C2H2-type zinc finger domain, as a novel gene involved in metal stress response, implying an alternative Cd-resilience mechanism. The expression profile of this gene shows that it plays a larger role in both development and metal stress adaption. These findings highlight the complexities of compound pollutant interactions, emphasizing the importance of including such dynamics in environmental risk assessments and control techniques.

An automatic measurement method for the response of Caenorhabditis elegans to chemicals

BACKGROUND

Caenorhabditis elegans is a widely used model animal. Chemotaxis assay is one of the experiments that study the effects of different chemicals on nematodes. It is mainly used to study the effects of different chemicals on the perception behavior of nematodes. By conducting this experiment, not only can the neurotoxicity of chemicals be reflected, but also the impact of chemicals on physiological functions regulated by the nervous system, such as nematode feeding behavior and basic motor ability.

OBJECTIVE

The experiment of detecting the response of nematode to chemicals is also a common method of chemical toxicity testing based on nematode models. In the analysis of worm tendency behavior, manual operations are generally used. Manually processing a large number of worms under a microscope is very time-consuming and labor-intensive. The current quantitative methods for nematode chemotaxis experiments are not only time-consuming and labor-intensive, but also biased in experimental results due to differences in judgment standards among experimenters. The automatic and efficient quantification method for nematode chemotaxis experiments is a very important technical difficulty in the field of nematode experiments.

METHODS

Here, we have designed an automatic quantification method for nematode chemotaxis experiments by incorporating image acquisition and processing techniques into the nematode experiment.

RESULTS

The experimental results show that the Pearson correlation coefficient between manual and automatic counting results is 0.978.

CONCLUSION

This proves the effectiveness of our method. Applying the automatic measurement method to replace manual counting by the experimenter can improve work efficiency, and reduce errors in human counting operations.

Multigenerational exposure of cadmium trans-generationally impairs locomotive and chemotactic behaviors in Caenorhabditis elegans

Cadmium is a naturally existing heavy metal and a notorious environmental pollutant. While its toxic outcomes and underlying mechanisms remain largely elusive. To explore the behavioral change caused by multigenerational exposure of cadmium to C. elegans, we challenged the C. elegans with cadmium for six generations and observed its impact on animal behaviors. Wild-type worms were randomly divided into two groups, the control and cadmium exposure groups. Locomotive and chemotactic behaviors were observed across six generations. Head thrashing frequency, chemotaxis index, and fold change index were used to evaluate the neurotoxicity of multigenerational cadmium exposure. Multigenerational cadmium exposure can trans-generationally increase the head thrashing frequency of C. elegans during swimming, and impair the chemotactic behaviors to isoamyl alcohol, diacetyl, and 2-nonanone. Our findings proposed a trans-generationally behavioral impact induced by multigenerational cadmium exposure.

C. elegans as an Animal Model to Study the Intersection of DNA Repair, Aging and Neurodegeneration

Since its introduction as a genetic model organism, Caenorhabditis elegans has yielded insights into the causes of aging. In addition, it has provided a molecular understanding of mechanisms of neurodegeneration, one of the devastating effects of aging. However, C. elegans has been less popular as an animal model to investigate DNA repair and genomic instability, which is a major hallmark of aging and also a cause of many rare neurological disorders. This article provides an overview of DNA repair pathways in C. elegans and the impact of DNA repair on aging hallmarks, such as mitochondrial dysfunction, telomere maintenance, and autophagy. In addition, we discuss how the combination of biological characteristics, new technical tools, and the potential of following precise phenotypic assays through a natural life-course make C. elegans an ideal model organism to study how DNA repair impact neurodegeneration in models of common age-related neurodegenerative diseases.