Cabral Lucélia, Júnior Gileno Vieira Lacerda, Pereira de Sousa Sanderson Tarciso, Dias Armando Cavalcante Franco, Lira Cadete Luana, Andreote Fernando Dini, Hess Matthias, de Oliveira Valéria Maia
Research Center for Chemistry, Biology and Agriculture (CPQBA), University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
Department of Soil Science, ''Luiz de Queiroz'' College of Agriculture, University of Sao Paulo, Piracicaba, São Paulo, Brazil.
Environ Pollut. 2016 Sep;216:460-469. doi: 10.1016/j.envpol.2016.05.078. Epub 2016 Jun 11.
Mangroves are complex and dynamic ecosystems highly dependent on diverse microbial activities. In the last decades, these ecosystems have been exposed to and affected by diverse human activities, such as waste disposal and accidental oil spills. Complex microbial communities inhabiting the soil and sediment of mangroves comprise microorganisms that have developed mechanisms to adapt to organic and inorganic contaminants. The resistance of these microbes to contaminants is an attractive property and also the reason why soil and sediment living microorganisms and their enzymes have been considered promising for environmental detoxification. The aim of the present study was to identify active microbial genes in heavy metals, i.e., Cu, Zn, Cd, Pb and Hg, and antibiotic resistomes of polluted and pristine mangrove sediments through the comparative analysis of metatranscriptome data. The concentration of the heavy metals Zn, Cr, Pb, Cu, Ni, Cd, and Hg and abundance of genes and transcripts involved in resistance to toxic compounds (the cobalt-zinc-cadmium resistance protein complex; the cobalt-zinc-cadmium resistance protein CzcA and the cation efflux system protein CusA) have been closely associated with sites impacted with petroleum, sludge and other urban waste. The taxonomic profiling of metatranscriptome sequences suggests that members of Gammaproteobacteria and Deltaproteobacteria classes contribute to the detoxification of the polluted soil. Desulfobacterium autotrophicum was the most abundant microorganism in the oil-impacted site and displayed specific functions related to heavy metal resistance, potentially playing a key role in the successful persistence of the microbial community of this site.
红树林是高度依赖多样微生物活动的复杂且动态的生态系统。在过去几十年里，这些生态系统一直受到各种人类活动的影响，如废物处理和意外石油泄漏。栖息在红树林土壤和沉积物中的复杂微生物群落包含已形成适应有机和无机污染物机制的微生物。这些微生物对污染物的抗性是一种吸引人的特性，也是土壤和沉积物中生存的微生物及其酶被认为在环境解毒方面具有潜力的原因。本研究的目的是通过对宏转录组数据的比较分析，确定受污染和原始红树林沉积物中对重金属（即铜、锌、镉、铅和汞）有活性的微生物基因以及抗生素抗性组。重金属锌、铬、铅、铜、镍、镉和汞的浓度以及与对有毒化合物抗性相关的基因和转录本丰度（钴 - 锌 - 镉抗性蛋白复合物；钴 - 锌 - 镉抗性蛋白CzcA和阳离子外排系统蛋白CusA）与受石油、污泥和其他城市废物影响的地点密切相关。宏转录组序列的分类分析表明，γ - 变形菌纲和δ - 变形菌纲的成员有助于污染土壤的解毒。自养脱硫杆菌是受石油影响地点中最丰富的微生物，并且表现出与重金属抗性相关的特定功能，可能在该地点微生物群落的成功存续中发挥关键作用。
