Effects of Graphene on Bacterial Community Diversity and Soil Environments of Haplic Cambisols in Northeast China

Abstract

Graphene is the thinnest and toughest two-dimensional nanomaterial yet discovered. However, it inevitably enters the biosphere, where it may pose potential risks to ecosystems. We investigated the impact of applied graphene concentrations on bacterial community diversity, physicochemical properties, and enzyme activities of Haplic Cambisols, the zonal soil of Northeastern China. Soils receiving 0, 10, 100, or 1000 mg kg−1 of graphene were incubated for 7, 15, 30, 60, or 90 days. Adding graphene significantly increased the community richness and diversity index of the bacterial community in Haplic Cambisols, as well as their abundances, but this impact varied with graphene concentration and incubation time. Compared with 0 mg kg−1 of graphene applied, soil bacteria abundance and diversity increased significantly during early stages of incubation (i.e., 7 and 15 days) under different concentrations of graphene, and was inhibited or remained unchanged by a longer incubation time, reaching a minima at 60 days but then following an upward trend. Graphene treatments influenced the bacterial community structure and metabolic function in Haplic Cambisols, and the bacterial community’s metabolic regulation mechanism varied with both incubation time and graphene concentration. The rank order of bacterial similarity in soils treated with graphene was 15 > 7 > 30 > 60 > 90 days. Throughout the incubation periods, except for a few unidentified bacteria, the relative abundances of Proteobacteria and Acidobacteria in the soil samples were the highest, with the number of Pseudomonas of Proteobacteria being particularly large. The rank order of bacterial abundance at the phylum level in Haplic Cambisols was 15 > 7 > 30 > 90 > 60 days. Graphene also influenced bacterial community diversity by affecting several key soil environmental factors, such as organic matter and hydrolytic nitrogen contents, as well as urease and catalase activities.

Microbiota and metabolome responses in the cecum and serum of broiler chickens fed with plant essential oils or virginiamycin

“…Extracted DNAs were measured using a NanoDrop ND-1000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) and agarose gel electrophoresis. www.nature.com/scientificreports www.nature.com/scientificreports/ PCR amplification was performed according to the method of Jinfeng Song 59 . The V3-V4 region of 16S rRNA genes was amplified using the 338F-806R primer set (338F: 55′-ACTCCTACGGGAGGCAGCA-3′.…”

“…Thermal cycle included initial denaturation of 98 °C for 2 min, followed by 25 cycles consisting of denaturation of 98 °C for 15 s, annealing at 55 °C for 30 s, extension of 72 °C for 30 s, and final extension of 72 °C for 5 min. PCR amplifiers were purified using Agencourt AMPure Beads (Beckman Coulter, Indianapolis, IN, USA) and quantified using PicoGreen dsDNA Assay Kit (Invitrogen, Carlsbad, CA, USA) 59 . After the individual sample was quantified, the amplicon were collected in equal amount, and pair-end 2×300 bp sequencing was performed using the Illlumina MiSeq platform with MiSeq Reagent Kit v3 at Shanghai Personal Biotechnology Co., Ltd (Shanghai, China) 5 .…”

Microbiota in the apical root canal system of tooth with apical periodontitis

“…PCR amplifications were performed using bacterial domain-specific primers, targeting variable regions V3-V4 of the 16S rRNA gene, using primers 338F (5’-ACTCCTACGGGAGGCAGCA-3′) and 802R (5’-GGACTACHVGGGTWTCTAAT-3′). Details of the PCR components and the thermal cycling procedures were described in [27]. Purification and quantification of the PCR amplicons were done by Agencourt AMPure Beads (Beckman Coulter, Indianapolis, IN) and PicoGreen dsDNA Assay Kit (Invitrogen, Carlsbad, CA, USA), respectively.…”

Cadmium Pollution Impact on the Bacterial Community of Haplic Cambisols in Northeast China and Inference of Resistant Genera

“…The soils growing L. olgensis seedlings were incubated at 25°C in the laboratory, and their soil water content regularly adjusted to 70% of the field water holding capacity. Because of the local cold climate, the experiment was set up in early June; leaves of L. olgensis seedlings would begin to turn yellow and fall off in late August, after Cd treatments for 50 days, which was previously been shown to be sufficient for soil microbes to adapt different Cd concentrations (Song et al 2018), soil sampling and analysis were conducted to determine the relevant indicators accurately.…”

“…Finally, ordination plots from a redundancy analysis (RDA) were used to explore the relationships between the soil bacterial community and environmental variables. The detailed information of DNA extraction, 16S rDNA amplicon pyrosequencing, sequence analysis, bioinformatics, and statistical analysis are the same as those in Song et al (2018).…”