Project description:Anthropogenic activities have dramatically increased the inputs of reactive nitrogen (N) into terrestrial ecosystems, with potentially important effects on the soil microbial community and consequently soil C and N dynamics. Our analysis of microbial communities in soils subjected to 14 years of 7 g N m-2 year-1 Ca(NO3)2 amendment in a Californian grassland showed that the taxonomic composition of bacterial communities, examined by 16S rRNA gene amplicon sequencing, was significantly altered by nitrate amendment, supporting the hypothesis that N amendment- induced increased nutrient availability, yielded more fast-growing bacterial taxa while reduced slow-growing bacterial taxa. Nitrate amendment significantly increased genes associated with labile C degradation (e.g. amyA and xylA) but had no effect or decreased the relative abundances of genes associated with degradation of more recalcitrant C (e.g. mannanase and chitinase), as shown by data from GeoChip targeting a wide variety of functional genes. The abundances of most N cycling genes remained unchanged or decreased except for increases in both the nifH gene (associated with N fixation), and the amoA gene (associated with nitrification) concurrent with increases of ammonia-oxidizing bacteria. Based on those observations, we propose a conceptual model to illustrate how changes of functional microbial communities may correspond to soil C and N accumulation.
Project description:The global significance of marine non-cyanobacterial diazotrophs, notably heterotrophic bacterial diazotrophs (HBDs), has become increasingly clear. Understanding N2 fixation rates for these largely uncultured organisms poses a challenge due to uncertain growth requirements and complex nitrogenase regulation. We identified Candidatus Thalassolituus haligoni as an Oceanospirillales member, closely related to other significant γ-proteobacterial HBDs. Pangenome analysis reinforces this classification, indicating the isolate belongs to the same species as the uncultured metagenome-assembled genome Arc-Gamma-03. Analysis of the nifH gene in amplicon sequencing libraries reveals the extensive distribution of Cand. T. haligoni across the Pacific, Atlantic and Arctic Oceans. Through combined proteomic analysis and N2 fixation rate measurements, we confirmed the isolate’s capacity for nitrate independent N2 fixation, although a clear understanding of nitrogenase regulation remains unclear. Overall, our study highlights the significance of Cand. T. haligoni as the first globally distributed, cultured model species within the understudied group of Oceanospirillales, and γ-HBDs in general.
Project description:Genome editing was conducted on a t(3;8) K562 model to investigate the effects of deleting different modules or CTCF binding sites within the MYC super-enhancer. To check mutations after targeting with CRISPR-Cas9 we performed amplicon sequencing using the Illumina PCR-based custom amplicon sequencing method using the TruSeq Custom Amplicon index kit (Illumina). The first PCR was performed using Q5 polymerase (NEB), the second nested PCR with KAPA HiFi HotStart Ready mix (Roche). Samples were sequenced paired-end (2x 250bp) on a MiSeq (Illumina).
Project description:Analysis of Cas9/sgRNA mutagenic activity at a variety of loci in zebrafish. Each loci has a control, where no Cas9/sgRNA were injected. This is amplicon sequencing with Illumina, after PCR amplification. Data was processed with ampliCan R package version 1.1.1.
Project description:Analysis of Cas9/sgRNA mutagenic activity at a variety of loci in zebrafish. Each loci has a control, where no Cas9/sgRNA were injected. This is amplicon sequencing with Illumina, after PCR amplification. Data was processed with ampliCan R package version 1.1.1.