RESUMO
This study aimed to determine if biotic contaminants originating from pig production farms are disseminated into soil and groundwater microbial communities. A spatial and temporal sampling of soil and groundwater in proximity to pig production farms was conducted, and quantitative PCR (Q-PCR) was utilized to determine the abundances of tetracycline resistance genes (i.e., tetQ and tetZ) and integrase genes (i.e., intI1 and intI2). We observed that the abundances of tetZ, tetQ, intI1, and intI2 in the soils increased at least 6-fold after manure application, and their abundances remained elevated above the background for up to 16 months. Q-PCR further determined total abundances of up to 5.88 × 10(9) copies/ng DNA for tetZ, tetQ, intI1, and intI2 in some of the groundwater wells that were situated next to the manure lagoon and in the facility well used to supply water for one of the farms. We further utilized 16S rRNA-based pyrosequencing to assess the microbial communities, and our comparative analyses suggest that most of the soil samples collected before and after manure application did not change significantly, sharing a high Bray-Curtis similarity of 78.5%. In contrast, an increase in Bacteroidetes and sulfur-oxidizing bacterial populations was observed in the groundwaters collected from lagoon-associated groundwater wells. Genera associated with opportunistic human and animal pathogens, such as Acinetobacter, Arcobacter, Yersinia, and Coxiella, were detected in some of the manure-treated soils and affected groundwater wells. Feces-associated bacteria such as Streptococcus, Erysipelothrix, and Bacteroides were detected in the manure, soil, and groundwater ecosystems, suggesting a perturbation of the soil and groundwater environments by invader species from pig production activities.
Assuntos
Criação de Animais Domésticos , Bactérias/isolamento & purificação , Água Subterrânea/microbiologia , Microbiologia do Solo , Suínos , Microbiologia da Água , Animais , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Sequência de Bases , DNA Bacteriano/genética , Proteínas de Escherichia coli/genética , Genes Bacterianos , Integrases/genética , Esterco/microbiologia , Consórcios Microbianos/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Resistência a Tetraciclina/genéticaRESUMO
The relationships between lead (Pb) uptake and iron/manganese plaque formation on rice roots were investigated with three cultivars. The results showed that the rice cultivars with indica consanguinity were more sensitive to soil Pb stress than the cultivar with japonica consanguinity. Pb concentrations and distribution ratios in root tissues were in the order: Shanyou 63 > Yangdao 6 > Wuyunjing 7, but Pb and Fe concentrations and distribution ratios in the plaques showed a reverse order. Mn concentrations and distribution ratios in the plaques of Wuyunjing 7 were significantly higher (P < 0.01 or 0.05) than those of Shanyou 63 and Yangdao 6. The results indicate that iron/manganese plaque on rice root can provide a barrier to soil Pb stress. The plaque will increase sequestration of Pb on rice root surface and in the rhizosphere, providing a means of external exclusion of soil Pb to some extent.
