Chromium (VI) induced oxidative stress in Hapalosiphon fontinalis

Abstract

Heavy metals in air, soil, and water are great threat to the environment. Effluents from paint, tannery, electroplating industries contaminate irrigation water, which in turn exhibit toxic response to many crops and microorganisms including cyanobacterial biofertilizers. In aquatic system Cr exist in many forms, whereas, Cr(VI) is most toxic. In the present study metabolic alteration were studied in a cyanobacterial biofertilizer (Hapalosiphon fontinalis) in response to chromium (VI) with special reference to oxidative stress. Maximum growth inhibition was observed at 0.5 mM Cr at 20th day. Lipid peroxidation as TBARS increased with the increase in chromium concentration and suggested free radical mediated toxicity. Elevated levels of β- carotene, astaxanthin, superoxide dismutase, catalase and ascorbate peroxidase indicated their role in survival strategy of the test organism.

Phytohormone up-regulates the biochemical constituent, exopolysaccharide and nitrogen metabolism in paddy-field cyanobacteria exposed to chromium stress

“…Hence, nitrogen metabolism is of central importance under stressful conditions. Earlier reports also indicate that biochemical constituents such as protein, carbohydrate and exopolysaccharides are also negatively affected by Cr stress (Bano et al, 2012;Gupta and Ballal, 2015).…”

“…Chromium induced negative effects on photoautotrophs are extensively studied by many workers (Gupta and Ballal, 2015;Tiwari et al, 2018;Singh and Prasad, 2019). It has been well studied that elevated level of Cr significantly affects the physiology and biochemistry of cyanobacteria such as Haplosiphon (Bano et al, 2012), Scendesmus (Kovacik et al, 2015a), Oscillatoria (Munagamage et al, 2016) and Haematococcus (Peng et al, 2019). Elevated concentrations of Cr affects many physiological processes such as photosynthetic pigments (Banerjee et al, 2004), photosynthesis (Prasad et al, 1991) including nitrogen metabolism.…”

Plastids of Marine Phytoplankton Produce Bioactive Pigments and Lipids

“…Actually, elevated levels of β-carotene and Asta were observed in the cyanobacteria Hapalosiphon fontinalis in response to chromium (VI) [256]. …”

Phytohormone up-regulates the biochemical constituent, exopolysaccharide and nitrogen metabolism in paddy-field cyanobacteria exposed to chromium stress

“…Chromium significantly declined the inorganic nitrogen uptake associated with decreased nitrogen and ammonia assimilating enzymes (NR, NiR, GS and GOGAT) except GDH (involved in alternative pathway of NH 4 + assimilation) [ 17 ]. Earlier reports also indicated that biochemical constituents such as protein and carbohydrate were negatively affected by Cr stress [ 18 , 19 ], beside this, EPS which is the polymer of carbohydrates and act primarily as a protective barrier against heavy metal stress were also found to decline under Cr stress.…”