当前位置： SCI文献检索 > ENVIRONMENTAL TOXICOLOGY期刊下所有文献 > Fluorescent Pseudomonas isolates from Mississippi Delta oxbow lakes: in vitro herbicide biotransformations.

Fluorescent Pseudomonas isolates from Mississippi Delta oxbow lakes: in vitro herbicide biotransformations.

Abstract：

:Fluorescent pseudomonads were a major component [log (10) 4.2-6.1 colony-forming units mL-1] of the culturable heterotrophic gram-negative bacterioplankton observed in three Mississippi Delta oxbow lakes in this study. Pure cultures of fluorescent pseudomonads were isolated from three Mississippi Delta oxbow lakes (18 per lake), using selective media S-1. Classical physiological tests and Biolog GN plates were used in criteria for taxonomic identification. Most isolates were identified as biotypes of Pseudomonas fluorescens 55% (II), 7% (III), and 25% (V). About 7% of the isolates were identified as P. putida and 7% as non-fluorescent Pseudomonas-like. Cell suspensions of these isolates were tested for their ability to metabolize/co-metabolize six 14C-radiolabeled herbicides (2,4-dichlorophenoxyacetic acid (2,4-D), cyanazine, fluometuron, metolachlor, propanil, and trifluralin) that are commonly used for crop production in this geographical area. Almost all (53 of 54) isolates transformed trifluralin via aromatic nitroreduction. Most isolates (70%) dechlorinated metolachlor to polar metabolites via glutathione conjugation. About 60% of the isolates hydrolyzed the amide bond of propanil (a rice herbicide) to dichloroaniline, with the highest frequency of propanil-hydrolyzing isolates observed in the lake from the watershed with rice cultivation. All propanil-hydrolyzing isolates were identified as P. fluorescens biotype II. No metabolism of cyanazine or fluometuron was observed by any isolates tested, indicating little or no potential for N-dealkylation among this group of bacterioplankton. No mineralization of 2,4-D labeled in either the carboxyl or ring position was observed. These results indicate that reductive and hydrolytic pathways for herbicide co-metabolism (aromatic nitroreduction, aryl acylamidase, and glutathione conjugation) are common in Mississippi Delta aquatic fluorescent pseudomonads; however, the potential for certain oxidative transformations (N-dealkylation, cyano group oxidation) may be rare in this group of bacterioplankton.

journal_name

Environ Toxicol

journal_title

Environmental toxicology

authors

Zablotowicz RM,Locke MA,Hoagland RE,Knight SS,Cash B

doi

10.1002/1522-7278(2001)16:1<9::aid-tox20>3.0.co;2-

keywords:

subject

Has Abstract

pub_date

2001-01-01 00:00:00

pages

9-19

issue

eissn

1520-4081

issn

1522-7278

pii

10.1002/1522-7278(2001)16:1<9::AID-TOX20>3.0.CO;2-

journal_volume

pub_type

杂志文章

在线工具

Fluorescent Pseudomonas isolates from Mississippi Delta oxbow lakes: in vitro herbicide biotransformations.