Detection by denaturing gradient gel electrophoresis of ammonia-oxidizing bacteria in microcosms of crude oil-contaminated mangrove sediments

Abstract

Currently, the effect of crude oil on ammonia-oxidizing bacterium communities from mangrove sediments is little understood. We studied the diversity of ammonia-oxidizing bacteria in mangrove microcosm experiments using mangrove sediments contaminated with 0.1, 0.5, 1, 2, and 5% crude oil as well as non-contaminated control and landfarm soil from near an oil refinery in Camamu Bay in Bahia, Brazil. The evolution of CO(2) production in all crude oil-contaminated microcosms showed potential for mineralization. Cluster analysis of denaturing gradient gel electrophoresis-derived samples generated with primers for gene amoA, which encodes the functional enzyme ammonia monooxygenase, showed differences in the sample contaminated with 5% compared to the other samples. Principal component analysis showed divergence of the non-contaminated samples from the 5% crude oil-contaminated sediment. A Venn diagram generated from the banding pattern of PCR-denaturing gradient gel electrophoresis was used to look for operational taxonomic units (OTUs) in common. Eight OTUs were found in non-contaminated sediments and in samples contaminated with 0.5, 1, or 2% crude oil. A Jaccard similarity index of 50% was found for samples contaminated with 0.1, 0.5, 1, and 2% crude oil. This is the first study that focuses on the impact of crude oil on the ammonia-oxidizing bacterium community in mangrove sediments from Camamu Bay.

Evaluation of the biodegradability of petroleum in microcosm systems by using mangrove sediments from Camamu Bay, Bahia, Brazil

“…These values indicate the adaptation of native microbial communities to the introduced carbon source. Similar results were reported by dos Santos et al (2012). Comparing the aver-age rate of respiration between the first and last day of the experiment, it is evident that the oil contamination affects microbial activity in the sediment ( Figure 1D).…”

“…Microcosm tests were conducted as previously described by dos Santos et al (2012). Twenty-two days after petroleum contamination, aliquots of 25 and 3 g were removed for gas chromatographic analysis and DNA extraction, respectively.…”

“…The respiration-caused release of CO 2 is the main parameter to measure the microbial activity of soil and has been applied in environmental impact assessments (Alef and Nannipieri, 1995;Machulla, 2003;Varma and Oelmüller, 2007;dos Santos et al, 2012;Silva et al, 2012). The amount of CO 2 released indicates mineralization (Moreira and Siqueira, 2006).…”

“…Soil and sediment contamination with petroleum hydrocarbons can affect the community's structure and functional diversity of resident bacteria and thus may have a major ecological impact (Kathiresan and Bingham, 2001; dos Santos et al, 2012). Mangroves (MGs), because of their location, are especially subject to impacts by offshore oil production activities that include exploration, production, refining, and transportation (Burns et al, 1993;Seabra, 2001;Li et al, 2007).…”

Functional Genes of Microorganisms, Comprehending the Dynamics of Agricultural Ecosystems

“…The loss of nitrogen fertilizers in crops may be 20-40% of the nitrogen applied 106 . Ammonia oxidation is the key step in the nitrogen cycle 86,107 were the enzyme ammonia monooxygenase (AMO) oxidizes ammoniac to hydroxylamine and is encoded by amoA and amoB genes 108 . The functional group of ammonia-oxidizing bacteria can be accessed through the amoA-1F e amoA-2R primers 2R, describe by 99 .…”