Isolation and characterization of an alkaliphilic bacterium capable of growing on 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid

The bacterial communities at two sulfidic, low salinity springs with no history of herbicide contamination were screened for their ability to grow on 2,4-dichlorophenoxyacetic acid (2,4-D). Nineteen isolates, closely matching the genera Bacillus, Halobacillus, Halomonas, Georgenia and Kocuria, showed diverse growth strategies on NaCl-supplemented and NaCl-free 2,4-D medium. The majority of isolates were halotolerant, growing best on nutrient rich broth with 0% or 5% NaCl; none of the isolates thrived in medium with 20% NaCl. The tfdA gene, which codes for an a – ketoglutarate dioxygenase and catalyzes the first step in 2,4-D degradation, was detected in nine of the salt spring isolates. The tfdAa gene, which shows ~60% identity to tfdA, was present in all nineteen isolates. Many of the bacteria described here were not previously associated with 2,4-D degradation suggesting these salt springs may contain microbial communities of interest for bioremediation.

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Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽

10.21273/hortsci.33.3.483a ◽

1998 ◽

Vol 33 (3) ◽

pp. 483a-483

Author(s):

Roy N. Keys ◽

Dennis T. Ray ◽

David A. Dierig

Keyword(s):

Field Experiments ◽

Reproductive Mode ◽

Dichlorophenoxyacetic Acid ◽

Initial Field ◽

Breeding Lines ◽

Reproductive Modes ◽

Desert Southwest ◽

2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

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Characterization of diverse 2,4-dichlorophenoxyacetic acid-degradative plasmids isolated from soil by complementation.

Applied and Environmental Microbiology ◽

10.1128/aem.61.5.1691-1698.1995 ◽

1995 ◽

Vol 61 (5) ◽

pp. 1691-1698 ◽

Cited By ~ 98

Author(s):

E M Top ◽

W E Holben ◽

L J Forney

Keyword(s):

Dichlorophenoxyacetic Acid ◽

2,4 Dichlorophenoxyacetic Acid

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Characterization of Hapten-Protein Conjugates: Antibody Generation and Immunoassay Development for Chlorophenoxyacetic Acid Pesticides

Journal of AOAC International ◽

10.1093/jaoac/92.6.1773 ◽

2009 ◽

Vol 92 (6) ◽

pp. 1773-1779 ◽

Cited By ~ 4

Author(s):

Robin C Boro ◽

K Vikas Singh ◽

C Raman Suri

Keyword(s):

Inhibitory Concentration ◽

Dichlorophenoxyacetic Acid ◽

Protein Conjugation ◽

Protein Conjugates ◽

Highly Sensitive ◽

Ic50 Values ◽

Chlorophenoxyacetic Acid ◽

2,4 Dichlorophenoxyacetic Acid

Abstract The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1500 ng/mL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

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