Genotoxic Impacts on Aquatic Green Algae-fed Daphnia Magna Organisms Subjected to Silver Nano clusters

Marisa Pepperberg^*
*Correspondence: Marisa Pepperberg, Department of Environmental Science, Poznan University, Rokietnicka 10, 60-806 Poznan, Poland, Email:

Keywords

Silver Nanoclusters (AgNCs) • Daphnia magna • Green algae • Genotoxicity

Introduction

Nanotechnology has ushered in a new era of innovation with applications spanning from medicine to electronics and environmental remediation. Among the myriad of nanomaterials, Silver Nanoclusters (AgNCs) have garnered substantial attention due to their unique physicochemical properties, such as high surface area, quantum confinement effects, and excellent catalytic activity. These properties make AgNCs attractive for various industrial and technological applications, including antimicrobial agents, imaging probes, and catalysts. However, as the production and use of AgNCs continue to rise, concerns about their environmental impacts have grown in parallel. Environmental concerns arise from the release of AgNCs into natural ecosystems, where they can interact with a wide range of organisms, potentially causing adverse effects. One crucial group of organisms susceptible to these impacts is Daphnia magna, a keystone species in freshwater ecosystems.

Literature Review

Daphnia magna, commonly referred to as water fleas, are microscopic crustaceans that play a pivotal role in aquatic food webs. They are primary consumers of green algae, making them a critical link in transferring energy from primary producers to higher trophic levels. Any adverse effects on Daphnia magna can cascade through the food web, affecting the entire ecosystem. Therefore, understanding the genotoxic impacts of AgNCs on Daphnia magna, especially when exposed through their diet of green algae, is of paramount importance. Genotoxicity refers to the capacity of a substance to cause damage to an organism's genetic material, resulting in mutations or other harmful genetic alterations. Genotoxic substances can affect an organism's DNA, leading to adverse biological effects. In the context of AgNCs, understanding their genotoxicity is essential in assessing their environmental impact. The mechanisms underlying the genotoxicity of AgNCs in Daphnia magna can be multifaceted and may involve direct interactions with DNA or indirect pathways [1].

AgNCs can generate Reactive Oxygen Species (ROS) when exposed to environmental conditions. ROS, such as superoxide radicals and hydrogen peroxide, can cause oxidative damage to DNA, proteins and lipids. In Daphnia magna, oxidative stress induced by AgNCs may result in DNA strand breaks and mutations. AgNCs can interact with various biomolecules, including proteins and enzymes, altering their function. This disruption can indirectly affect DNA repair mechanisms, potentially leading to an accumulation of DNA damage over time. AgNCs may interfere with the normal process of mitosis, the cell division process essential for growth and development. Aberrant mitotic events can result in chromosomal abnormalities and genetic mutations.

Several studies have investigated the genotoxic effects of AgNCs on Daphnia magna. These experiments typically expose Daphnia magna to environmentally relevant concentrations of AgNCs and assess genotoxicity through various endpoints, including the comet assay, or single-cell gel electrophoresis assay, is a common technique used to measure DNA damage in individual cells. Studies have reported increased DNA fragmentation in Daphnia magna exposed to AgNCs. The micronucleus test is another widely employed assay to assess genotoxicity. It detects the formation of micronuclei, small additional nuclei that can result from chromosomal damage. Several studies have observed an increase in micronucleus formation in Daphnia magna exposed to AgNCs.

Transcriptomics studies have revealed changes in the expression of genes related to DNA repair and stress response in Daphnia magna exposed to AgNCs, providing further evidence of genotoxicity. Understanding the genotoxic impacts of AgNCs on Daphnia magna is crucial because these organisms occupy a central role in aquatic ecosystems [2]. The repercussions of genotoxicity in Daphnia magna can reverberate throughout the ecosystem in the following ways. Daphnia magna serve as a critical link between primary producers (e.g., green algae) and higher trophic levels, such as fish. Any disruption in Daphnia magna populations due to genotoxicity can alter the flow of energy through the food web. Reduced Daphnia magna populations can lead to declines in fish populations and other predators that depend on them as a food source.

The alteration of trophic interactions can have cascading effects on the biodiversity of aquatic ecosystems. A decrease in Daphnia magna populations can result in a proliferation of green algae, as their primary herbivore is no longer controlling their abundance. This can lead to water quality issues, such as algal blooms, and negatively impact other species that rely on a balanced ecosystem. Genotoxicity can reduce the genetic diversity of Daphnia magna populations. Reduced genetic diversity can make populations more vulnerable to environmental stressors and less capable of adapting to changing conditions. This can weaken the resilience of Daphnia magna populations and, by extension, the entire ecosystem. Mitigating the genotoxic impacts of AgNCs on Daphnia magna and aquatic ecosystems is a complex challenge. However, several strategies can be considered to minimize these impacts such as implementing regulations on the production, use, and disposal of AgNCs is a fundamental step in reducing their environmental impact. Additionally, monitoring programs can help track the presence of AgNCs in natural water bodies and assess their concentrations over time.

Developing environmentally friendly methods for synthesizing AgNCs, such as green synthesis using plant extracts or microorganisms, can reduce the environmental footprint of AgNCs production. Green synthesis methods often result in AgNCs with reduced toxicity compared to conventional chemical methods. Coating AgNCs with biocompatible materials can mitigate their toxic effects. These coatings can prevent direct contact between AgNCs and biological tissues, reducing the release of toxic ions and ROS. Conducting thorough environmental risk assessments for AgNCs is essential to understand their potential impacts. These assessments should consider exposure pathways, concentrations, and potential ecological consequences. In cases where ecosystems have been impacted by AgNCs, ecological restoration efforts may be necessary to restore balance. This could include the reintroduction of Daphnia magna populations and the implementation of measures to control algal blooms [3].

Discussion

The genotoxic impacts of Silver Nanoclusters (AgNCs) on aquatic green algae-fed Daphnia magna organisms represent a critical area of study in the field of nano toxicology and environmental science. In this discussion, we will delve deeper into several key aspects surrounding this topic, including the complexity of assessing genotoxicity, the broader ecological implications, and potential challenges and opportunities for future research and mitigation. Assessing genotoxicity in aquatic organisms exposed to AgNCs is a complex endeavor. Several challenges need to be addressed to draw meaningful conclusions. Determining the precise concentration-response relationships for AgNCs-induced genotoxicity in Daphnia magna can be challenging. Studies often use a range of concentrations, making it essential to pinpoint the threshold at which genotoxic effects become significant [4].

The duration of exposure to AgNCs is a crucial factor. Short-term exposure may not reveal the full extent of genotoxicity, as effects could manifest over time due to accumulated damage. AgNCs come in various sizes, shapes, and surface coatings, each potentially affecting their toxicity. Understanding how these variations influence genotoxicity is essential for risk assessment. The conditions under which experiments are conducted can influence outcomes. Factors such as temperature, pH, and nutrient availability can interact with AgNCs and alter their toxicity. The genotoxic impacts of AgNCs on Daphnia magna extend beyond individual organisms and can have profound ecological consequences.

As primary consumers of green algae, Daphnia magna play a pivotal role in regulating algal populations. Genotoxicity-induced declines in Daphnia magna can trigger trophic cascades, leading to imbalances in ecosystem dynamics. Reduced Daphnia magna populations can result in unchecked algal growth, leading to algal blooms. These blooms can alter water quality, deplete oxygen and harm other aquatic organisms [5]. Genotoxicity can reduce the genetic diversity of Daphnia magna populations. Lower genetic diversity makes populations more vulnerable to environmental changes and reduces their capacity to adapt. Shifts in trophic interactions and algal blooms can lead to declines in biodiversity. Species that rely on a balanced ecosystem may face challenges in a disrupted environment.

The study of AgNCs genotoxicity in Daphnia magna is a dynamic field with on-going research and evolving methodologies. Further research is needed to elucidate the precise mechanisms by which AgNCs induce genotoxicity in Daphnia magna. This includes understanding how AgNCs interact with cellular components and how these interactions lead to DNA damage. To better assess real-world scenarios, studies should aim to replicate environmental conditions as closely as possible. This includes considering the presence of natural organic matter and other nanoparticles in aquatic systems. The effects of AgNCs may not manifest immediately, and long-term studies are crucial for capturing delayed genotoxic effects and their ecological consequences. Expanding research to investigate how AgNCs genotoxicity affects higher trophic levels, such as fish that prey on Daphnia magna, can provide a more comprehensive understanding of ecosystem impacts.

Research efforts should also focus on developing effective mitigation and remediation strategies to reduce AgNCs' environmental impact. This includes exploring technologies to remove or neutralize AgNCs in aquatic environments. The genotoxic impacts of AgNCs on Daphnia magna underscore the importance of responsible nanotechnology development. It is crucial to balance the potential benefits of nanomaterials with their environmental risks. Governments and regulatory bodies should establish clear guidelines for the production, use, and disposal of AgNCs. These regulations should be informed by rigorous scientific research. Encouraging the development and adoption of green synthesis methods for AgNCs can reduce their environmental footprint and toxicity. Raising public awareness about the potential environmental impacts of nanomaterials can foster responsible consumer choices and promote industry accountability. Industries that produce and utilize AgNCs should take responsibility for understanding and mitigating their environmental impacts [6].

Conclusion

The genotoxic impacts of AgNCs on Daphnia magna organisms, particularly when exposed through their diet of green algae, represent a significant environmental concern. Assessing and mitigating these impacts require a multidisciplinary approach, combining toxicology, ecology, and nanotechnology. As we advance in our understanding of AgNCs genotoxicity, we must work collectively to develop responsible practices and regulations that safeguard aquatic ecosystems while harnessing the benefits of nanotechnology for society's advancement.

Acknowledgement

None.

Conflict of Interest

There are no conflicts of interest by author.

References

1. Lu, Yizhong and Wei Chen. “Sub-nanometre sized metal clusters: From synthetic challenges to the unique property discoveries.” Chem Soc Rev 41 (2012): 3594–3623.

Google Scholar, Crossref, Indexed at

2. Diez, Isabel and Robin HA Ras. “Fluorescent silver nanoclusters.” Nanoscale 3 (2011): 1963–1970.

Google Scholar, Crossref, Indexed at

3. Xu, Hangxun and Kenneth S. Suslick. “Water-soluble fluorescent silver nanoclusters.” Adv Mater 22 (2010): 1078–1082.

Google Scholar, Crossref, Indexed at

4. Guidez, Emilie B. and Christine M. Aikens. “Theoretical analysis of the optical excitation spectra of silver and gold nanowires.” Nanoscale 4 (2012): 4190–4198.

Google Scholar, Crossref, Indexed at

5. Leclerc, Simon and Kevin J. Wilkinson. “Bioaccumulation of nanosilver by Chlamydomonas reinhardtii-nanoparticle or the free ion?.” Environ Sci Technol 48 (2014): 358–364.

Google Scholar, Crossref, Indexed at

6. Kaveh, Rashid, Yue-Sheng Li, Sibia Ranjbar and Christopher L. Brueck, et al. “Changes in Arabidopsis thaliana gene expression in response to silver nanoparticles and silver ions.” Environ Sci Technol 47(2013): 10637–10644.

Google Scholar, Crossref, Indexed at