Project description:All organisms throughout the tree of life sense and respond to their surface environments. To discriminate from among mucosal surface environmental cues, we grew Streptococcus gordonii biofilms over night at 37C on surfaces coated with the salivary mucin MUC5B, or a low density protein fraction derived from human saliva.
Project description:Histone proteins have traditionally been thought to be restricted to eukaryotes and most archaea, with eukaryotic nucleosomal histones deriving from their archaeal ancestors. In contrast, bacteria lack histones as a rule. However, in recent years histone proteins have been identified in a few bacterial clades, in particular the phylum Bdellovibrionota, and these histones have been proposed to exhibit a range of divergent features compared to histones in archaea and eukaryotes. However, no experimental functional genomic studies of the properties of Bdellovibrionota chromatin have been carried out. In this work, we map the landscape of chromatin accessibility, active transcription and three-dimensional genome organization in a member of Bdellovibrionota (a Bacteriovorax strain). We find that Bacteriovorax chromatin is characterized by preferential accessibility around promoter regions, similar to what is observed in eukaryotes with compact genomes such as yeast, and also to some archaea. As in eukaryotes, chromatin accessibility positively correlates with gene expression. Mapping active transcription through single-strand DNA (ssDNA) profiling revealed that Bacteriovorax promoters exhibit very strong polymerase pausing, unlike in yeast, but similar to the state of mammalian and fly promoters. Finally, the Bacteriovorax genome exists in a three-dimensional (3D) conformation analogous to that of other bacteria without histones, organized by the parABS system and along the axis defined by replication origin and termination regions. These results provide a foundation for understanding the chromatin biology of the unique Bdellovibrionota bacteria and the deep evolution of chromatin organization across the tree of life.
Project description:Pear is an important fruit tree widely distributed around the world. Here, we present a draft pear proteome atlas based on 24 tissues.
Project description:Protein reference databases are a critical part of producing efficient proteomic analyses. However, the method for constructing clean, efficient, and comprehensive protein reference databases is lacking. Existing methods either do not have contamination control procedures, or these methods rely on a three-frame and/or six-frame translation that sharply increases the search space and harms MS results. Herein we propose a framework for constructing a customized comprehensive proteomic reference database (CCPRD) from draft genomes and deep sequencing transcriptomes. Its effectiveness is demonstrated by incorporating the proteomes of nematocysts from endoparasitic cnidarian: myxozoans. By applying customized contamination removal procedures, contaminations in omic data were successfully identified and removed. This is an effective method that does not result in over-decontamination. This can be shown by comparing the CCPRD MS results with an artificially-contaminated database and another database with removed contaminations in genomes and transcriptomes added back. CCPRD outperformed traditional frame-based methods by identifying 35.2%-50.7% more peptides and 35.8%-43.8% more proteins, with a maximum 84.6% in size reduction. A BUSCO analysis showed that the CCPRD maintained a relatively high level of completeness compared to traditional methods. These results confirm the superiority of the CCPRD over existing methods in peptide and protein identification numbers, database size, and completeness. By providing a general framework for generating the reference database, the CCPRD, which does not need a high-quality genome, can potentially be applied to any organisms and significantly contribute to proteomic research.
Project description:DNA was extracted from two ash tree samples, one tolerant and one susceptible to ash dieback. The DNA was sequenced using Nanopore technologies and the methylation was called against the new genome (BioProject PRJNA865134, SAMN30100368, genome JANJPF000000000 ) to identify differentially methylated regions between both samples. Manuscript title: Fraxinus excelsior updated long-read genome reveals the importance of MADS-box genes in tolerance mechanisms against ash dieback, G3:Genes|Genomes|Genetics