Evaluation of the gene expression changes in Nile tilapia (Oreochromis niloticus) as affected by the bio-removal of toxic textile dyes from aqueous solution in small-scale bioreactor

Abstract

A laboratory-scale bioremediation unit was designed, built and tested for the bio-removal of several Direct textile dyes. Four experiments were carried out to assess the efficiency of the bioremediation unit using Aspergillus niger fungal strain. Three commonly used Direct dyes and textile dyes mixture (simulated effluent: Direct brown, Direct violet, Direct green) were tested in this study. The strain of A. niger was efficient in the removal of the three Direct dyes. The decolorization percentages of the dyes after 24 h of incubation were 56.2, 51.7, and 95.4% for Direct brown, Direct green, Direct violet dyes, respectively. The percentages increased up to 79.4, 86.4, and 96.7% after 72 h of incubation for the same dyes, respectively. The results also showed that the fungal strain reduced the chemical oxygen demand values of simulated dye effluents from 165 to 564 mg/l with most of the dyes. The assessment of bioremediation products on biomodel was conducted using a fresh water fish. The liver and brain of Nile tilapia were tested to evaluate the expression of genes coding for several proteins related to stress such as metallothioneins (MTs), cytochrome P450 (CYP450), and heat shock proteins (HSPs). To assess the alterations in the gene expression, ten animals from each group were killed after 4 weeks of treatment. The results revealed significant increases in the brain and hepatic mRNA levels of all stress protein genes MT, CYP450, Hsp70a, b, and Hsp47 in the fish groups treated with industrial Direct violet, green, and brown dye water. Exposure of tilapia to bioremediation products after treatment with A. niger fungi reduced the over-expression of the stress protein genes in the brain and liver tissues.

Genotoxicity and Trace Elements Contents Analysis in Nile Tilapia (Oreochromis niloticus) Indicated the Levels of Aquatic Contamination at Three Egyptian Areas

“…Mohanty et al ( 85 ) demonstrated that it is a sensitive indicator of exposure of aquatic animals to different pollutants and causes an abnormal increase of proteins in the nucleus and cytosol ( 86 , 87 ). Due to trace elements contamination, Hsp70 protein bands in muscle tissues of Nile tilapia caught from Mariout and Abbassa was obvious but absent in muscle tissues of Nile tilapia caught from Aswan ( Figure 3A ), similar to AbdEl-Rahim et al ( 88 ) and Deen ( 89 ). The expression of Hsp70 was upregulated in the liver ( Figures 3A,B ) because it is responsible for the accumulation and detoxification of toxins ( 90 ) and performs multiple key functions as energy metabolism.…”

Enhancing systemic resistance in faba bean (Vicia faba L.) to Bean yellow mosaic virus via soil application and foliar spray of nitrogen-fixing Rhizobium leguminosarum bv. viciae strain 33504-Alex1

“…The total RNA was used as a template for cDNA synthesis. As described by AbdEl-Rahim et al (2010) , DNase I-treated RNA (2 μg) was reverse transcribed to cDNA using oligo (dT) and random hexamer primers with the reverse transcriptase enzyme of Super-Script II (Invitrogen, United States). The amplified cDNA was used as a template for qRT-PCR through sets of PR primers ( Table 1 ) with β-actin gene (housekeeping gene) to normalize the transcription levels.…”

Plantago lagopus extract as a green fungicide induces systemic resistance against Rhizoctonia root rot disease in tomato plants

“…SPECTROstar Nano was used to determine the purity and concentration of extracted RNA (BMG Labtech, Ortenberg, Germany). As previously described ( AbdEl-Rahim et al, 2010 ; Abdelkhalek et al, 2019 ), the isolated RNA was utilized to generate cDNA using a reverse transcriptase (RT) enzyme. In an Eppendorf cycler (Hamburg, Germany), the RT reaction was conducted at 42°C for 1 h and then deactivated at 80°C for 5 min.…”