No abstract

The Yanshan Mountains are one of the oldest mountain ranges in the world. They are located in an ecologically sensitive zone in northern China near the Hu Huanyong Line. In this metagenomic study, we investigated the diversity of Actinobacteria in soils at 10 sites (YS1–YS10) on the Yanshan Mountains. First, we assessed the effect of different soil prtreatment on Actinobacteria recovery. With the soil pretreatment method: air drying of the soil sample, followed by exposure to 120°C for 1 h, we observed the higher Actinobacteria diversity in a relatively small number of clone libraries. No significant differences were observed in the Actinobacterial diversity of soils from sites YS2, YS3, YS4, YS6, YS8, YS9, or YS10 (P > 0.1). However, there were differences (P < 0.05) from the YS7 site and other sites, especially in response to environmental change. And we observed highly significant differences (P < 0.001) in Actinobacterial diversity of the soil from YS7 and that from YS4 and YS8 sites. The climatic characteristics of mean active accumulated temperature, annual mean precipitation, and annual mean temperature, and biogeochemical data of total phosphorus contributed to the diversity of Actinobacterial communities in soils at YS1, YS3, YS4, and YS5 sites. Compared to the climatic factors, the biogeochemical factors mostly contributed in shaping the Actinobacterial community. This work provides evidence that the diversity of Actinobacterial communities in soils from the Yashan Mountains show regional biogeographic patterns and that community membership change along the north-south distribution of the Hu Huanyong Line.

CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPRassociated protein 9) systems have emerged as a powerful tool for genome editing in many organisms.The wide use of CRISPR/Cas9 systems may be due to the fact that these systems contain a simple guide RNA (sgRNA) that is relatively easy to design and they are very versatile with the ability to simultaneously target multiple genes within a cell (Varshney et al., 2015). We have developed a CRISPR/Cas9 system to delete large genomic fragments (exceeding 30 kb) in Saccharomyces cerevisiae. One application of this technology is to study the effects of large-scale deletions of nonessential genes which may give insight into the function of gene clusters within chromosomes at the molecular level. In this protocol, we describe the general procedures for large fragment deletion in S. cerevisiae using CRISPR/Cas9 including: how to design CRISPR arrays and how to construct Cas9-crRNA expression plasmids as well as how to detect mutations introduced by the system within S. cerevisiae cells.