Single-Cell Transcriptome Analysis Reveals Six Subpopulations Reflecting Distinct Cellular Fates in Senescent Mouse Embryonic Fibroblasts.

Replicative senescence is a hallmark of aging, which also contributes to individual aging. Mouse embryonic fibroblasts (MEFs) provide a convenient replicative senescence model. However, the heterogeneity of single MEFs during cellular senescence has remained unclear. Here, we conducted single-cell RNA sequencing on senescent MEFs. Principal component analysis showed obvious heterogeneity among these MEFs such that they could be divided into six subpopulations. Three types of gene expression analysis revealed distinct expression features of these six subpopulations. Trajectory analysis revealed three distinct lineages during MEF senescence. In the main lineage, some senescence-associated secretory phenotypes were upregulated in a subset of cells from senescent clusters, which could not be distinguished in a previous bulk study. In the other two lineages, a possibility of escape from cell cycle arrest and coupling between translation-related genes and ATP synthesis-related genes were also discovered. Additionally, we found co-expression of transcription factor HOXD8 coding gene and its potential target genes in the main lineage. Overexpression of Hoxd8 led to senescence-associated phenotypes, suggesting HOXD8 is a new regulator of MEF senescence. Together, our single-cell sequencing on senescent MEFs largely expanded the knowledge of a basic cell model for aging research.

Development of a rapid and high-throughput molecular method for detecting the F200Y mutant genotype in benzimidazole-resistant isolates of Fusarium asiaticum.

BACKGROUND: The point mutation at codon 200 (TTC→TAC, F200Y) of the ß2 -tubulin gene confers resistance to benzimidazole fungicide in Fusarium asiaticum. These isolates with this mutation have been detected mainly by determining the minimum inhibitory concentration (MIC) of fungicides, which is always time consuming, tedious and inefficient. RESULTS: A visual, rapid and efficient method with high specificity was developed, based on loop-mediated isothermal amplification (LAMP). Six sets of LAMP primers were designed, and one set was optimised specifically to distinguish the F200Y mutant genotype. With the optimal LAMP primers, concentrations of LAMP components were optimised. The optimal reaction conditions were 57-64 °C for 75 min. The feasibility of the LAMP assay for detection of the F200Y mutant genotype of F. asiaticum was demonstrated by assaying diseased wheat spikelets that were artificially inoculated in the field. CONCLUSION: The new LAMP assay had good specificity, sensitivity, stability and repeatability. It will be useful for assessing the risk of F. asiaticum populations with carbendazim resistance developing in the field, and will also provide important reference data for integrated control of Fusarium head blight caused by F. asiaticum. © 2016 Society of Chemical Industry.

Development and application of loop-mediated isothermal amplification for detection of the F167Y mutation of carbendazim-resistant isolates in Fusarium graminearum.

Resistance of Fusarium graminearum to carbendazim is caused by point mutations in the ß2-tubulin gene. The point mutation at codon 167 (TTT → TAT, F167Y) occurs in more than 90% of field resistant isolates in China. To establish a suitable method for rapid detection of the F167Y mutation in F. graminearum, an efficient and simple method with high specificity was developed based on loop-mediated isothermal amplification (LAMP). A set of four primers was designed and optimized to specially distinguish the F167Y mutation genotype. The LAMP reaction was optimal at 63 °C for 60 min. When hydroxynaphthol blue dye (HNB) was added prior to amplification, samples with DNA of the F167Y mutation developed a characteristic sky blue color after the reaction but those without DNA or with different DNA did not. Results of HNB staining method were reconfirmed by gel electrophoresis. The developed LAMP had good specificity, stability and repeatability and was suitable for monitoring carbendazim-resistance populations of F. graminearum in agricultural production.