Project description:In Gram-positive bacteria, the direct quorum sensing activation pathway involves sensing a autoinducing peptide (AIP) inside the cell after its maturation, export and re-internalization. Once internalized, the AIP interacts with a transcriptional regulator belonging to the RRNPP family. In Streptococcus thermophilus, AIPs are matured by a protease called Eep, exported by an ABC transporter called PptAB, and re-imported by another ABC transporter called Ami. We used a deep sequencing approach (RNAseq) to identify all genes whose expression is controlled by a quorum sensing mechanism involving the three partners PptAB, Eep and Ami. Thus, we studied the mRNA transcriptional profiles in Streptococcus thermophilus strain LMD-9 and 3 mutants deleted for the pptAB, eep and amiCDE genes. The four strains were also deleted for the comR gene in order to get rid off the genes whose expression is controlled by ComR. Indeed, ComR is a RRNPP regulator and its regulon has been already identified. The four strains were grown in a chemically defined medium and cell were harvested at the end of the exponential phase (OD600 1).
Project description:Comr protein was found to be a major regulator of gene activity in drosophila spermatocytes. We obtained Comr binding profile to determine targets of Comr. Comr binding in drosophila male germ line cells was determined using DamID technique. Comparison of Dam-Comr binding to Dam-alone signal in duplicate for each sample type.
Project description:Comr protein was found to be a major regulator of gene activity in drosophila spermatocytes. We obtained Comr binding profile to determine targets of Comr. Comr binding in drosophila male germ line cells was determined using DamID technique.
Project description:To investigate phage-host interactions in Streptococcus thermophilus, a phage-resistant derivative (SMQ-301R) was obtained by challenging a Tn917 library of phage-sensitive strain S. thermophilus SMQ-301 with virulent phage DT1. Mutants of phages DT1 and MD2 capable of infecting SMQ-301 and SMQ-301R were isolated at a frequency of 10(-6). Four host range phage mutants were analyzed further and compared to the two wild-type phages. Altogether, three genes (orf15, orf17, and orf18) contained point mutations leading to amino acid substitutions and were responsible for the expanded host range. These three proteins were also identified in both phages by N-terminal sequencing and/or matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The results suggest that at least three phage structural proteins may be involved in phage-host interactions in S. thermophilus.
Project description:Streptococcus thermophilus strain ND03 is a Chinese commercial dairy starter used for the manufacture of yogurt. It was isolated from naturally fermented yak milk in Qinghai, China. We present here the complete genome sequence of ND03 and compare it to three other published genomes of Streptococcus thermophilus strains.
