Effects of food contaminated with cadmium and copper on hemocytes of Steatoda grossa (Araneae: Theridiidae)

Transcriptomic and metabolomic profiles of Pirata subpiraticus in response to copper exposure

Copper (Cu) contamination represents a persistent and significant form of heavy metal pollution in agricultural ecosystems, posing serious threats to organisms in current society. Spiders serve as crucial biological indicators for assessing the impact of heavy metals-induced toxicity. However, the specific molecular responses of spiders to Cu exposure and the mechanisms involved are not well understood. In our study, the wolf pond spiders, Pirata subpiraticus, were exposed to Cu for 21 d, resulting in a notable decline in survival rates compared with the control (n = 50, p < 0.05). We observed an increased expression of enzymes like glutathione peroxidase and superoxide dismutase (p < 0.05), signaling a strong oxidative stress response crucial for counteracting the harmful effects of reactive oxygen species. This response was corroborated by a rise in malondialdehyde levels (p < 0.05), a marker of lipid peroxidation and oxidative damage. Transcriptomic and metabolomic analyses revealed 2004 differentially expressed genes (DEGs) and 220 metabolites (DEMs). A significant number of these DEGs were involved in the glutathione biosynthetic process and antioxidant activity. A conjoint analysis revealed that under the Cu stress, several important enzymes and metabolites were altered (e.g., cathepsin A, legumain, and lysosomal acid lipase), affecting the activities of key biological processes and components, such as lysosome and insect hormone biosynthesis. Additionally, the protein interaction network analysis showed an up-regulation of processes like the apoptotic process, glutamate synthase activity, and peroxisome, suggesting that spiders activate cellular protective strategies to cope with stress and maintain homeostasis. This study not only deepens our understanding of spider biology in the context of environmental stress but also makes a significant contribution to the field of environmental stress biology.

Immunostimulation of Parasteatoda tepidariorum (Araneae: Theridiidae) in juvenile and adult stages. Immunity reactions to injury with foreign body and Bacillus subtilis infection

To assess the immune potential of spiders, in the present study juvenile and adult females of Parasteatoda tepidariorum were exposed to Bacillus subtilis infection, injury by a nylon monofilament and a combination of both. The expression level of selected immune-related genes: defensin 1 (PtDEF1), lysozyme 1 (PtLYS1), lysozyme C (PtLYSC), lysozyme M1 (PtLYSM1), autophagy-related protein 101 (PtATG101), dynamin (PtDYN) and heat shock proteins (HSP70) (PtHSPB, PtHSPB2A, PtHSPB2B), production of lysozyme and HSP70 proteins, and hemocytes viability were measured. The obtained results indicated expression of the lysozyme, autophagy-related protein and HSP70 genes in both ontogenetic stages of P. tepidariorum. It has been also shown that the simultaneous action of mechanical and biological factors causes higher level of lysozyme and HSP70, cell apoptosis intensity and lower level of hemocytes viability than in the case of exposure to a single immunostimulant. Moreover, mature females showed stronger early immune responses compared to juveniles.

Effects of chronic exposure to cadmium and copper on the proteome profile of hemolymph in false widow spider Steatoda grossa (Theridiidae)

The aim of this study was to evaluate the quantitative and qualitative changes in the proteome of the hemolymph of female Steatoda grossa spiders (Theridiidae) that were chronically exposed to cadmium and copper in food and were additionally immunostimulated (phorbol 12-myristate 13-acetate (PMA); bacterial suspensions: Staphylococcus aureus (G+), Pseudomonas fluorescens (G-). It was found that the expression of nearly 90 proteins was altered in cadmium-intoxicated spiders and more than 60 in copper-exposed individuals. Regardless of the type of metal used, these proteins were mainly overexpressed in the hemolymph of the exposed spiders. On the other hand, immunostimulation did not significantly change the number of proteins with altered expression in metal-intoxicated individuals. Hemocyanin (Hc) was found to be the most abundant of the proteins identified with altered expression. In copper-intoxicated spiders, immunostimulation increased the expression of A-, E-, F-, and G-chain-containing proteins, while in the case of cadmium-intoxicates spiders, it decreased the expression of E- and A-chain-containing Hc and increased the expression of G-chain-containing Hc. Regardless of the type of metal and immunostimulant used, there was an increase in the expression of actin. In addition, cadmium increased the expression of cullin, vimentin, and ceruloplasmin. The changes observed in the expression of hemolymph proteins indicate their protective function in S. grossa (Theridiidae) spiders under conditions of metal exposure.

Transcriptomic analysis of cadmium toxicity and molecular response in the spiderling of Pirata subpiraticus

Cadmium (Cd) is a kind of toxic heavy metal widely distributed in the environment, posing life-threatening challenges to organisms. The paddy field spider is a natural enemy of pests and an essential component of rice biodiversity. Nonetheless, the effects of Cd stress on the postembryonic development of spiders and its detailed mechanism remain to be investigated. In the present study, we found that Cd stress posed adverse impacts on the growth indicators (e.g., carapace length, development duration, and survival rate) and increased the levels of three antioxidants (i.e., superoxide dismutase, glutathione S-transferase, and glutathione peroxidase) in the spiderlings of Pirata subpiraticus. An in-depth transcriptome analysis was employed in the study, and the results displayed that differentially expressed genes (DEGs) involved in postembryonic morphogenesis, development involved in symbiotic interaction, postembryonic development, and growth were distinctively altered under Cd stress. Further enrichment analysis showed that Cd exposure could activate the apoptosis pathway in the spider via the up-regulation of several key factors, including caspase-10, α-tubulin, actin, etc. In addition, we demonstrated that the increased level of glutathione-related enzymes in spiderlings was caused by the activation of glutathione metabolic pathway. The altered hedgehog signaling pathway might affect cell proliferation, tissue patterning, and development of spiderlings. Further protein interaction network displayed that Cd stress could affect multiple biological processes in spiderlings, particularly cellular response to stimulus and system development. To sum up, this study can provide multi-level perspectives to understand the toxicity of Cd on the growth and development of spiders.

The effect of selected immunostimulants on hemocytes of the false black widow Steatoda grossa (Theridiidae) spiders under chronic exposition to cadmium

The aim of this study was to analyze whether, and to what extent, long-term exposure to cadmium, administered in sublethal concentrations by the oral route, caused changes in the immune potential of hemocytes in adult female Steatoda grossa spiders. We used artificial and natural immunostimulants, namely phorbol 12-myristate 13-acetate (PMA) and bacterial cell suspension based on Gram-positive (G+, Staphylococcus aureus) and Gram-negative (G-, Pseudomonas fluorescens) bacteria, to compare the status of hemocytes in nonstimulated individuals and those subjected to immunostimulation. After cadmium exposure, the percentage of small nongranular hemocytes in response to G+ cell suspension and PMA mitogen was decreased. Furthermore, in the cadmium-intoxicated spiders the percentage of plasmatocytes after immunostimulation remained lower compared to the complementary control group. Exposure to cadmium also induced several degenerative changes, including typical apoptotic and necrotic changes, in the analyzed types of cells. Immunostimulation by PMA mitogen and G+ bacterial suspension resulted in an increase in the number of cisterns in the rough endoplasmic reticulum of granulocytes, in both the control group and cadmium-treated individuals. These changes were accompanied with a low level of metallothioneins in hemolymph. Chronic cadmium exposure may significantly weaken the immune defense system of spiders during infections.

Dietary cadmium (Cd) reduces hemocyte level by induction of apoptosis in Drosophila melanogaster

Drosophila melanogaster larvae ensure continuous proliferation and differentiation of hemocytes to maintain a fixed range of different blood cell types during its various stages of development. Variation in this number is often an indicator of animal well-being, its genotype or an effect of environmental perturbation, including exposure to heavy metals. The present study investigates the effect of Cd on larval hemocytes. Embryos were allowed to grow in metal media till third instar larvae and finally circulating hemocyte were collected. The number of major hemocytes, plasmatocytes and crystal cells was determined to be lowered in Cd exposed animals. Our results also showed modulation of antioxidant biology of Cd exposed hemocytes by changing the major antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) activity, and decreasing reduced glutathione (GSH) levels in hemocytes suspended in the hemolymph. Acridine orange (AO) staining further revealed induction of apoptosis in hemocytes of metal treated larvae. Our results suggest a negative impact of Cd exposure on the hemocytes of the Drosophila larvae culminating in their lowered count by induction of apoptosis.

Immunotoxic effects of force-fed ethephon on model organism Galleria mellonella (Lepidoptera: Pyralidae)

Incorporation of chemical substances like plant growth regulators in agricultural practices to boost production has become inevitable; thus, they have accumulated in the environment in tremendous amounts. However, due to their nonselective nature, they affect several components of the ecosystem like the invertebrates. In this study, therefore, the effects of force-fed Ethephon on the cellular mediated immune system of model insect G. mellonella larvae were investigated using the lethal doses LD₂₅ and LD₅₀ determined in a previous study. Our results indicated that treating G. mellonella larvae with ETF significantly reduces the number of circulating hemocytes and also reduces the number of live cells while increasing the apoptotic and necrotic cell ratios at all doses. Additionally, ETF increased the number of spherulocytes, oenocytes and prohemocytes as well as the mitotic indices while reducing the number of granulocytes in circulation but did not alter the number of plasmatocytes. Moreover, the in vivo encapsulation assays showed significant suppression of the encapsulation abilities of the ETF treated G. mellonella larval hemocytes at both ETF doses. The findings of the current study are indicative of the ecotoxic effects that may arise due to ETF and that its usage should be controlled or monitored as it poses major threats to several organisms and the ecosystem at large.

Autophagy: a necessary defense against extreme cadmium intoxication in a multigenerational 2D experiment

Autophagy is a natural process that aims to eliminate malfunctioning cell parts, organelles or molecules under physiological conditions. It is also induced in response to infection, starvation or oxidative stress to provide energy in case of an energy deficit. The aim of this 2-dimensional study was to test if, and if so, how, this process depends on the concentration of cadmium in food (with Cd concentrations from 0 to 352 μg of Cd per g of food (dry weight)-D1 dimension) and the history of selection pressure (160 vs 20 generations of exposure to Cd-D2 dimension). For the study, the 5th instar larvae of a unique strain of the moth Spodoptera exigua that was selected for cadmium tolerance for 160 generations (44 μg of Cd per g of food (dry weight)), as well as 20-generation (11, 22 and 44 μg of Cd per g of food (dry weight)) and control strains, were used. Autophagy intensity was measured by means of flow cytometry and compared with life history parameters: survivability and duration of the 3rd larval stage. The highest values of autophagy markers were found in the groups exposed to the highest Cd concentration and corresponded (with a significant correlation coefficient) to an increased development duration or decreased survivorship in the respective groups. In conclusion, autophagy is probably initiated only if any other defense mechanisms, e.g., antioxidative mechanisms, are not efficient. Moreover, in individuals from pre-exposed populations, the intensity of autophagy is lower.

Enzymatic and non-enzymatic detoxification in Lycosa terrestris and Pardosa birmanica exposed to single and binary mixture of copper and lead

Organisms employ various enzymatic and non-enzymatic detoxification mechanisms to minimize the harmful effects of metal pollution in the terrestrial environment. We examined the effects of copper (Cu), lead (Pb) and their mixture (Cu + Pb) on glutathione (GSH), metallothionein (MTs), cytochrome P450 (CYP 450), carboxylesterase (CarbE), acetylcholinesterase (AchE) and glutathione S-transferase (GST) in Lycosa terrestris and Pardosa birmanica via two exposure routes, i.e., soil and food for 10, 20 and 40 days. The present results revealed that the accumulation of Cu and Pb in both spiders' species increase with exposure duration and depend on the route of exposure and type of metal. The activities of CarbE, GST, and MTs significantly increased with increasing metal body burden for all experimental treatments. The CYP 450 activity exhibited a significant time-dependent decrease with increasing Cu concentration in both species. The AchE activity was significantly inhibited on Pb exposure via soil and Cu + Pb exposure via both routes. The decrease in the level of GSH was measured on Cu + Pb exposure via both routes. Thus, all these enzymatic and non-enzymatic responses are sensitive to the metals tested and could serve as early warning indicators for assessing the effects of metal pollution in these species.

Effects of short- and long-term exposure to cadmium on salivary glands and fat body of soil centipede Lithobius forficatus (Myriapoda, Chilopoda): Histology and ultrastructure

Cadmium (Cd) is the most widely studied heavy metal in terms of food-chain accumulation and contamination because it can strongly affect all environments (e.g., soil, water, air). It can accumulate in different tissues and organs and can affect the organism at different levels of organization: from organs, tissues and cells though cell organelles and structures to activation of mechanisms of survival and cell death. In soil-dwelling organisms heavy metals gather in all tissues with accumulation properties: midgut, salivary glands, fat body. The aim of this study was to describe the effects of cadmium on the soil species Lithobius forficatus, mainly on two organs responsible for gathering different substances, the fat body and salivary glands, at the ultrastructural level. Changes caused by cadmium short- and long-term intoxication, connected with cell death (autophagy, apoptosis, necrosis), and the crosstalk between them, were analyzed. Adult specimens of L. forficatus were collected in a natural environment and divided into three experimental groups: C (the control group), Cd1 (cultured in soil with 80 mg/kg of CdCl₂ for 12 days) and Cd2 (cultured in soil with 80 mg/kg of CdCl₂ for 45 days). Transmission electron microscopy revealed ultrastructural alterations in both of the organs analyzed (reduction in the amount of reserve material, the appearance of vacuoles, etc.). Qualitative analysis using TUNEL assay revealed distinct crosstalk between autophagy and necrosis in the fat body adipocytes, while crosstalk between autophagy, apoptosis and necrosis in the salivary glands was detected in salivary glands of the centipedes examined here. We conclude that different organs in the body can react differently to the same stressor, as well as to the same concentration and time of exposure. Different mechanisms at the ultrastructural level activate different types of cell death and with different dynamics.

Unravelling the ZnO-NPs mechanistic pathway: Cellular changes and altered morphology in the gastrointestinal tract of the earthworm Eisenia andrei

A major uptake route of nanoparticles (NPs) occurs via the gastrointestinal (GI) tract. When GI tract cells are exposed, NPs cytotoxic effects are observed that subsequently adversely affect the GI tract morphology and have consequences for the whole organism. The aim of this study was to understand the mechanism of effects caused by ZnO-NPs compared to Zn ions on the earthworm Eisenia andrei. The following aspects of individually exposed earthworms were investigated: 1) qualitative structural alterations in the gut epithelium and chloragogen cells of the GI tract, 2) quantitative changes within chloragogen tissues after 48 h of exposure (using morphometric analysis), and 3) the ADP/ATP ratio in homogenized tissue of the whole organism after 21 days of exposure to contaminated soil (contamination phase) followed by 14 days of elimination in clean soil (decontamination phase) to identify possible recovery. Both ZnO-NPs and Zn ions adversely affect the gut epithelium and chloragogen tissue of earthworms after 48 h of exposure to contaminated soil. Morphometric measurements revealed that the proportions of debris vesicles in the chloragocytes were significantly lower in worms exposed to ZnO-NPs than in worms exposed to Zn ions. Moreover, numerous spherite granules were observed in the chloragocytes of ionic Zn-treated worms, but not the ZnO-NPs-treated worms, suggesting differential regulation of these Zn forms. The Zn cytotoxic effect was not reflected in ADP/ATP ratio measurements. Our study provides new insights into nano-specific effects that are distinctive from ion regulation inside the GI tract and furthers our understanding of the relationship between effects at the cellular and whole-body levels.

Assessment of bioaccumulation of cu and Pb in experimentally exposed spiders, Lycosa terrestris and Pardosa birmanica, using different exposure routes

Major concerns exist regarding the environmental and human health risks caused by exposure to heavy metals. Spiders are often used as a model in ecotoxicological studies to assess soil pollution. Here, we measured the bioaccumulation of copper (Cu) and lead (Pb) in spiders, Lycosa terrestris and Pardosa birmanica, by inductively coupled plasma mass spectrometry (ICP-MS). We investigated whether Cu and Pb accumulation differs according to different spider species, single versus combined metal exposure, and routes of exposure. Spiders were exposed to 10 mM CuSO₄ and 10 mM PbCl₂ solutions separately or in combination (10 mM + 10 mM) through different exposure routes (spiked soil and food) for 6 weeks. The effect of metals on the survival and body mass of exposed and unexposed (control) spiders was determined. We found that in both spider species, accumulation of metals increased with exposure time. In single metal exposure, Cu accumulation from food was higher than soil exposure in both spider species, whereas the opposite was observed for Pb. The simultaneous uptake of Cu and Pb significantly decreased from food and soil, respectively. Soil exposure caused more accumulation of metals in L. terrestris than P. birmanica. Metal exposure via contaminated food caused higher mortality compared to soil exposure. Body mass of both spider species was significantly decreased and negatively correlated with metal's concentration. Overall, our results show that bioaccumulation efficiency of Cu and Pb differs significantly in spiders exposed to metal's mixture compared to single metal exposure and is dependent on the exposure route, the type of metal, and spider species. More understanding of the effects of exposure to metal mixture and exposure routes is essential for designing and supporting risk assessment and ecological monitoring programs.

Effect of long-term cadmium and copper intoxication on the efficiency of ampullate silk glands in false black widow Steatoda grossa (Theridiidae) spiders

The aim of the study was to compare cellular effects of xenobiotic cadmium and biogenic copper in ampullate silk glands of false black widow Steatoda grossa spider after long-term exposure via ingestion under laboratory conditions. Both the level of selected detoxification parameters (glutathione S-transferase, catalase, and the level of total antioxidant capacity) and degree of genotoxic changes (comet assay) were determined in the silk glands. Additionally the contents of selected amino acids (L-Ala, L-Pro, L-His, L-Phe, DL-Ile, and DL-Asn) in the hunting webs produced by spiders of this species were assessed. The ability of S. grossa females to accumulate cadmium was higher than that for copper. Long-term exposure of spiders to copper did not change the level of detoxification parameters, and the level of DNA damage in the cells of ampullate silk glands was also low. Cadmium had a stronger prooxidative and genotoxic effect than copper in the cells of the analyzed silk glands. However, regardless of the type of metal used, no significant changes in the level of amino acids in silk were found. The obtained results confirmed the effectiveness of metal neutralization mechanisms in the body of the studied spider species, which results in the protection of the function of ampullate silk glands.

Evaluation of selected biological properties of the hunting web spider (Steatoda grossa, Theridiidae) in the aspect of short- and long-term exposure to cadmium

The study aimed at comparing the effects of short- and long-term exposure of Steatoda grossa female spiders to cadmium on the web's architecture, its energy content, and ultrastructure of ampullate glands. Simple food chain model (medium with 0.25 mM CdCl₂ → Drosophila hydei flies → spider (for 4 weeks or 12 months) was used for the exposure. Analysis of Cd content provided evidence that silk fibers of the web are well protected against its incorporation irrespectively of the exposure period. Long-term exposure to cadmium resulted in the occurrence of numerous autophagosomes with degenerated organelles as well as apoptotic and necrotic cells in the ampullate glands. Concurrently, the individual silk fibers building double and multiple combination complexes were significantly thinner than in the control threads. Moreover, exposed spiders spun net with smaller mean calorific value than did the control individuals. Hence, evaluation of both the diameter of silk fibers and calorific value of the web can serve as biomarkers of the effects caused by exposure of these predators to cadmium.