title: Lead-enhanced siderophore production and alteration in cell morphology in a Pb-resistant Pseudomonas aeruginosa strain 4EA.
abstract: A lead-resistant bacterial strain 4EA from soil contaminated with car battery waste from Goa, India was isolated and identified as Pseudomonas aeruginosa. This lead-resistant bacterial isolate interestingly revealed lead-enhanced siderophore (pyochelin and pyoverdine) production up to 0.5 mM lead nitrate whereas cells exhibit a significant decline in siderophore production above 0.5 mM lead nitrate. The bacterial cells also revealed significant alteration in cell morphology as size reduction when exposed to 0.8 mM lead nitrate. Enhanced production of siderophore was evidently detected by chrome azurol S agar diffusion (CASAD) assay as increase in diameter of orange halo, and reduction in bacterial size along with significant biosorption of lead was recorded by scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX). Pseudomonas aeruginosa strain 4EA also exhibits cross tolerance to other toxic metals viz. cadmium, mercury, and zinc besides resistance to multiple antibiotics such as ampicillin, erythromycin, amikacin, cephalexin, co-trimoxazole, mecillinam, lincomycin, ciphaloridine, oleondamycin, and nalidixic acid.
authors.affiliation: Department of Microbiology, Laboratory of Bacterial Genetics and Environmental Biotechnology, Goa University, Taleigao Plateau, Goa, 403 206, India.
authors.forename: Milind Mohan
authors.initials: MM
authors.lastname: Naik
authors.forename: Santosh Kumar
authors.initials: SK
authors.lastname: Dubey
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004785:Environmental Pollutants / Q000378:metabolism*; D007194:India; D007854:Lead / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D011550:Pseudomonas aeruginosa / Q000166:cytology* / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D017262:Siderophores / Q000096:biosynthesis*; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D013052:Spectrometry, X-Ray Emission
chemical_list: D000900:Anti-Bacterial Agents; D004785:Environmental Pollutants; D017262:Siderophores; D012987:Soil; D007854:Lead