A new perspective to aberrations caused by barium and vanadium ions on Lens culinaris Medik

Nuclear and morpho-histopathological alterations in Astyanax altiparanae exposed to effluent from the process of anodizing aluminum

Aluminum is a metal widely used from household utensils to civil construction. Anodizing aluminum is a procedure to form a thick layer of aluminum oxide on the surface in order to confer greater resistance to the material. This process generates an effluent with acidic pH and a high concentration of sulfate. Alternatives for the treatment of this effluent involve the use of the chemical precipitation technique, which can be used with salts of barium chloride (BaCl2), calcium chloride (CaCl2), and aluminum hydroxide with commercial limestone (Cc/Al (OH)3). The objective of this study was to evaluate the toxicity of effluents on Astyanax altiparanae (Lambari), by means of somatic, genetic, morphological, and histological markers after 24 and 96 h of exposure. After measuring the biometric data of the animals and the weight of the liver, we found that the condition factor (K) of individuals exposed to the effluent CaCl2 showed a slight reduction in growth after 96 h while the hepatosomatic index (HSI) remained unchanged for all effluents in both sampling times. The micronucleus test with erythrocytes indicated that the raw effluent (E2) induced nuclear changes after 24 h; however, this effect did not persist after 96 h of exposure. Branchial arches were collected and according to Bernet's index for histopathology, all effluents except Cc/Al (OH)3, induced significant changes in the gills. In accordance with the index of Poleksic and Mitrovic-Tutundzic, CaCl2 was the only effluent to compromise branchial operation. The branchial morphology investigated by SEM showed that the raw effluent (E1) induced injuries and compromised gill functions. This study reinforces the importance of biological tests for the assessment and validation of physical chemicals used and effluent treatment techniques as well as the development and application of biological parameters before the wastewater release, whether in a raw state or a treated one.

DNA fragmentation and multifaceted toxicity induced by high-dose vanadium exposure determined by the bioindicator Allium test

In this study, the toxicity of vanadium (VCI₃) in Allium cepa L. was studied. Germination-related parameters, mitotic index (MI), catalase (CAT) activity, chromosomal abnormalities (CAs), malondialdehyde (MDA) level, micronucleus (MN) frequency and superoxide dismutase (SOD) activity were investigated. The effects of VCI₃ exposure on the DNA of meristem cells were investigated with the help of comet assay, and the relationships between physiological, cytogenetic and biochemical parameters were revealed by correlation and PCA analyses. A. cepa bulbs were germinated with different concentrations of VCI₃ for 72 h. As a result, the maximum germination (100%), root elongation (10.4 cm) and weight gain (6.85 g) were determined in the control. VCI₃ treatment caused significant decreases in all tested germination-related parameters compared to the control. The highest percentage of MI (8.62%) was also observed in the control. No CAs were found in the control, except for a few sticky chromosomes and unequal distribution of chromatin (p > 0.05). VCI₃ treatment caused significant decreases in MI and increases in the frequencies of CAs and MN, depending on the dose. Similarly, the comet assay showed that DNA damage scores increased with increasing VCI₃ doses. The lowest root MDA (6.50 µM/g) level and SOD (36.7 U/mg) and CAT (0.82 OD_240nmmin/g) activities were also measured in the control. VCI₃ treatment caused significant increases in root MDA levels and antioxidant enzyme activities. Besides, VCI₃ treatment induced anatomical damages such as flattened cell nucleus, epidermis cell damage, binuclear cell, thickening in the cortex cell wall, giant cell nucleus, damages in cortex cell and unclear vascular tissue. All examined parameters showed significant negative or positive correlations with each other. PCA analysis confirmed the relations of investigated parameters and VCI₃ exposure.

Paracetamol ecotoxicological bioassay using the bioindicators Lens culinaris Med. and Pisum sativum L

Paracetamol is one of the most widely used drugs worldwide, yet its environmental presence and hazardous impact on non-target organisms could rapidly increase. In this study, the possible cytotoxic effects of paracetamol were evaluated using two bioindicator plants Lens culinaris and Pisum sativum. Concentrations of 500, 400, 300, 200, 100, 50, 25, 5, 1 mg L-1, and a control (distilled water) were used for a total of 10 treatments, which were subsequently applied on seeds of Lens culinaris Med. and Pisum sativum L.; after 72 h of exposure, root growth, mitotic index, percentage of chromosomal abnormalities, and the presence of micronucleus were evaluated. The cytotoxic effect of paracetamol on L. culinaris and P. sativum was demonstrated, reporting the inhibition of root growth, the presence of abnormalities, and a significant micronucleus index at all concentrations used, which shows that this drug has a high degree of toxicity.

Improved Mineral Acquisition, Sugars Metabolism and Redox Status after Mycorrhizal Inoculation Are the Basis for Tolerance to Vanadium Stress in C3 and C4 Grasses

Vanadium (V) can be beneficial or toxic to plant growth and the interaction between arbuscular mycorrhizal fungi (AMF) and V stress was rarely investigated at physiological and biochemical levels of plant groups (C3 and C4) and organs (roots and shoots). We tested the potential of AMF to alleviate the negative effects of V (350 mg V/Kg soil) on shoots and roots of rye and sorghum. Relative to sorghum (C4), rye (C3) showed higher levels of V and lower levels of key elements under V stress conditions. V inhibited growth, photosynthesis, and induced photorespiration (increased HDR & GO activities) and oxidative damage in both plants. AMF colonization reduced V stress by differently mitigating the oxidative stress in rye and sorghum. This mitigation was accompanied with increases in acid and alkaline phosphatase activities in plant roots and increased organic acids and polyphenols exudation into the soil, thus reduced V accumulation (29% and 58% in rye and sorghum shoot, respectively) and improved absorption of mineral nutrients including Ca, Mg and P. AMF colonization improved photosynthesis and increased the sugar accumulation and metabolism. Sugars also acted as a supplier of C skeletons for producing of antioxidants metabolite such as ascorbate. At the antioxidant level, rye was more responsive to the mitigating impact of AMF. Higher antioxidants and detoxification defence system (MTC, GST, phenolics, tocopherols and activities of CAT, SOD and POX) was recorded for rye, while sorghum (C4) improved its GR activity. The C3/C4-specificity was supported by principal component analysis. Together, this study provided both fundamental and applied insights into practical strategies to mitigate the phytotoxicity hazards of V in C3 and C4 grasses. Moreover, our results emphasize the importance of AMF as an environment-friendly factor to alleviate stress effects on plants and to improve growth and yield of unstressed plants.

Sulfur supply reduces barium toxicity in Tanzania guinea grass (Panicum maximum) by inducing antioxidant enzymes and proline metabolism

Sulfur (S) can play essential roles in protecting plants against abiotic stress, including heavy metal toxicity. However, the effect of this nutrient on plants exposed to barium (Ba) is still unknown. This study was designed to evaluate the S supply on oxidative stress and the antioxidant system of Tanzania guinea grass under exposure to Ba, grown in a nutrient solution under greenhouse conditions. It was studied the influence of S/Ba combinations in nutrient solution on oxidative stress indicators (hydrogen peroxide, malondialdehyde, and proline) and antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase). The treatments consisted in thirteen S/Ba combinations in the nutrient solution (0.1/0.0; 0.1/5.0; 0.1/20.0; 1.0/2.5; 1.0/10.0; 1.9/0.0 - control; 1.9/5.0; 1.9/20.0; 2.8/2.5; 2.8/10.0; 3.7/0.0; 3.7/5.0 and 3.7/20.0 mM of S and Ba, respectively). The plants were grown for two growth periods, which consisted of fourteen days of S supply and the eight days of Ba exposure each one. The severe S deficiency decreased the superoxide dismutase activity, regardless of Ba exposure in recently expanded leaves and culms plus sheaths. However, supplemental S supply (above 1.9 mM S, which corresponds to S supply adequate to plant growth) it improved the superoxide dismutase activity in these tissues under high Ba concentrations. Conversely, the severe S deficiency increased the activities of catalase, ascorbate peroxidase, and glutathione reductase in grass leaves slightly, without Ba exposure influence. It was observed that the supplemental S supply also induced the guaiacol peroxidase activity and proline production in culms plus sheaths under high Ba rates, showing values until 2.5 and 3.1 folds higher than the control treatment, respectively. In plants under exposure to 20.0 mM Ba, the supplemental S supply decreased the malondialdehyde content in culms plus sheaths in 17% compared to 1.9 mM S. These results indicate that supplemental S supply can mitigate Ba toxicity in Tanzania guinea grass, mainly by improving superoxide dismutase and guaiacol peroxidase activities, and proline metabolism.

Evaluation of cytotoxic potential of chlorpyrifos using Lens culinaris Med as efficient bioindicator

The aim of this study was to evaluate the cytotoxic effect of different concentrations of chlorpyrifos (CPF), using L. culinaris apical cells as a biological indicator. L. culinaris seeds were exposed to different concentrations of chlorpyrifos (0, 1, 3, 5, 7, 8, 10 and 15 mg L^-1) and a control solution based on distilled water. Subsequently, root growth was measured during 24, 48 and 72 h. Therefore, the mitotic index (MI) and the number of cellular abnormalities were determined at 72 h. According to the obtained results, a decrease in root size was observed in the concentrations of T5 (8 mg L^-1) and T6 (10 mg L^-1). On the other hand, it was evidenced that, through all the evaluated concentrations, the inhibition of mitosis in the concentrations of T5 (8 mg L^-1), T6 (10 mg L^-1) and T7 (15 mg L^-1) was greater than 50%. Additionally, a variety of chromosomal abnormalities were reported, such as Micronuclei, sticky chromosomes in anaphase, chromosome disruption, irregular anaphase, nucleus absence, nuclear lesions, chromosomes grouped in metaphase, anaphase bridges, metaphase sticky chromosomes, present in all concentrations evaluated. Consequently, the presence of micronuclei in the concentrations of 8 mg L^-1, 10 mg L^-1 and 15 mg L^-1 indicates that the CPF is a highly cytotoxic substance to L. culinaris. Therefore, L. culinaris is a plant species that offers a feasible experimental model to be implemented in laboratory studies with the purpose to evaluate the cytotoxic effect of pesticides.