Metabolism and toxicity of 1- and 2-methylnaphthalene and their derivatives in cyanobacteria

2-Naphthoate catabolic pathway in Burkholderia strain JT 1500

“…The benzalpyruvate is presumably hydrated and undergoes aldol cleavage to give phthalaldehydate [5] and pyruvate, both of which were formed in equimolar amounts in the absence of NAD ϩ . In the subsequent steps, phthalaldehydate is metabolized to phthalate [6] and protocatechuate [9] via 4,5-dihydroxyphthalate [8]. We were able to demonstrate the conversion of phthalaldehydate to phthalate, 4,5-dihydroxyphthalate to protocatechuate, and protocatechuate to ␤-carboxy-cis,cis-muconic acid [10].…”

“…When 4,5-dihydroxy-o-phthalate [8] was incubated with cell extracts, protocatechuate was formed and oxidized (25). The oxygen uptake after addition of 4,5-dihydroxyphthalate to the extract was 77.4 nmol of oxygen min Ϫ1 mg Ϫ1 .…”

“…(1R,2S)-cis-1,2-Dihydro-1,2-dihydroxy-2-naphthoate was thus considered an intermediate between 2-naphthoate and 1-hydroxy-2-naphthoate, but it was not transformed by whole cells or their extracts. We conclude that this diol is not responsible for the formation of 1-hydroxy-2-naphthoate from 2-naphthoate but that one of the other three diastereomers is not eliminated as a potential intermediate for a dehydration reaction.Fused carbo-and heterocyclic ring systems are a class of aromatic compounds which are of great concern because of their toxicity, carcinogenicity, and resistance to biodegradation (7,8,28). As products of combustion and industrial synthesis and as components of fossil fuels, aromatic ring systems are ubiquitous environmental pollutants and are abundant near urban and industrial centers.…”

“…Fused carbo-and heterocyclic ring systems are a class of aromatic compounds which are of great concern because of their toxicity, carcinogenicity, and resistance to biodegradation (7,8,28). As products of combustion and industrial synthesis and as components of fossil fuels, aromatic ring systems are ubiquitous environmental pollutants and are abundant near urban and industrial centers.…”

Impact of Oil-Based Drilling Fluids Emulsification on Tolerance and Hydrocarbon-Degrading Potential of Ralstonia pickettii and Alcaligenes piechandii

“…The diesel assimilation by microorganisms decreased as diesel concentration increased from 0.2% to 1%, and completely stopped above this level [12]. The solubilization of diesel PAHs via derivatization (phenolic or quinonic) or cosolvent addition further reduced acceptable (non-toxic) hydrocarbon concentrations [8,13]. The mechanisms of hydrocarbon toxicity against microorganisms involves partitioning of the hydrocarbons into the cytoplasmic membrane, which alters: energy transduction; nutrient and enzyme transfer across the biological membranes; and damages the cytoplasmic membrane which leads to leakage of macromolecules (RNA, proteins, etc), and hence cell death [8,14].…”