Southwest University

About: Southwest University is a education organization based out in Chongqing, China. It is known for research contribution in the topics: Population & Bombyx mori. The organization has 29772 authors who have published 27755 publications receiving 409441 citations. The organization is also known as: Southwest University in Chongqing & SWU.

Efficient CRISPR/Cas9-mediated Targeted Mutagenesis in Populus in the First Generation

Abstract: Recently, RNA-guided genome editing using the type II clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein (Cas) system has been applied to edit the plant genome in several herbaceous plant species. However, it remains unknown whether this system can be used for genome editing in woody plants. In this study, we describe the genome editing and targeted gene mutation in a woody species, Populus tomentosa Carr. via the CRISPR/Cas9 system. Four guide RNAs (gRNAs) were designed to target with distinct poplar genomic sites of the phytoene desaturase gene 8 (PtoPDS) which are followed by the protospacer-adjacent motif (PAM). After Agrobacterium-mediated transformation, obvious albino phenotype was observed in transgenic poplar plants. By analyzing the RNA-guided genome-editing events, 30 out of 59 PCR clones were homozygous mutants, 2 out of 59 were heterozygous mutants and the mutation efficiency at these target sites was estimated to be 51.7%. Our data demonstrate that the Cas9/sgRNA system can be exploited to precisely edit genomic sequence and effectively create knockout mutations in woody plants.

Energy-efficient dynamic offloading and resource scheduling in mobile cloud computing

Abstract: Mobile cloud computing (MCC) as an emerging and prospective computing paradigm, can significantly enhance computation capability and save energy of smart mobile devices (SMDs) by offloading computation-intensive tasks from resource-constrained SMDs onto the resource-rich cloud. However, how to achieve energy-efficient computation offloading under the hard constraint for application completion time remains a challenge issue. To address such a challenge, in this paper, we provide an energy-efficient dynamic offloading and resource scheduling (eDors) policy to reduce energy consumption and shorten application completion time. We first formulate the eDors problem into the energy-efficiency cost (EEC) minimization problem while satisfying the task-dependency requirements and the completion time deadline constraint. To solve the optimization problem, we then propose a distributed eDors algorithm consisting of three subalgorithms of computation offloading selection, clock frequency control and transmission power allocation. More importantly, we find that the computation offloading selection depends on not only the computing workload of a task, but also the maximum completion time of its immediate predecessors and the clock frequency and transmission power of the mobile device. Finally, our experimental results in a real testbed demonstrate that the eDors algorithm can effectively reduce the EEC by optimally adjusting the CPU clock frequency of SMDs based on the dynamic voltage and frequency scaling (DVFS) technique in local computing, and adapting the transmission power for the wireless channel conditions in cloud computing.

Complete Resequencing of 40 Genomes Reveals Domestication Events and Genes in Silkworm (Bombyx)

Abstract: A single-base pair resolution silkworm genetic variation map was constructed from 40 domesticated and wild silkworms, each sequenced to approximately threefold coverage, representing 99.88% of the genome. We identified ∼16 million single-nucleotide polymorphisms, many indels, and structural variations. We find that the domesticated silkworms are clearly genetically differentiated from the wild ones, but they have maintained large levels of genetic variability, suggesting a short domestication event involving a large number of individuals. We also identified signals of selection at 354 candidate genes that may have been important during domestication, some of which have enriched expression in the silk gland, midgut, and testis. These data add to our understanding of the domestication processes and may have applications in devising pest control strategies and advancing the use of silkworms as efficient bioreactors.

Single base-resolution methylome of the silkworm reveals a sparse epigenomic map

Abstract: Epigenetic regulation in insects may have effects on diverse biological processes. Here we survey the methylome of a model insect, the silkworm Bombyx mori, at single-base resolution using Illumina high-throughput bisulfite sequencing (MethylC-Seq). We conservatively estimate that 0.11% of genomic cytosines are methylcytosines, all of which probably occur in CG dinucleotides. CG methylation is substantially enriched in gene bodies and is positively correlated with gene expression levels, suggesting it has a positive role in gene transcription. We find that transposable elements, promoters and ribosomal DNAs are hypomethylated, but in contrast, genomic loci matching small RNAs in gene bodies are densely methylated. This work contributes to our understanding of epigenetics in insects, and in contrast to previous studies of the highly methylated genomes of Arabidopsis and human, demonstrates a strategy for sequencing the epigenomes of organisms such as insects that have low levels of methylation.