Project description:Bronchioloalveolar carcinoma (BAC), a subtype of lung adenocarcinoma (ADC) without stromal, vascular, or pleural invasion, is considered an in situ tumor with a 100% survival rate. However, the histological criteria for invasion remain controversial. BAC-like areas may accompany otherwise invasive adenocarcinoma, referred to as mixed type adenocarcinoma with BAC features (AWBF). AWBF are considered to evolve from BAC, representing a paradigm for malignant progression in ADC. However, the supporting molecular evidence remains forthcoming. Here, we have studied the genomic changes of BAC and AWBF by array comparative genomic hybridization (CGH). We used submegabase-resolution tiling set array CGH to compare the genomic profiles of 14 BAC or BAC with focal area suspicious for invasion with those of 15 AWBF. Threshold-filtering and frequency-scoring analysis found that genomic profiles of noninvasive and focally invasive BAC are indistinguishable and show fewer aberrations than tumor cells in BAC-like areas of AWBF. These aberrations occurred mainly at the subtelomeric chromosomal regions. Increased genomic alterations were noted between BAC-like and invasive areas of AWBF. We identified 113 genes that best differentiated BAC from AWBF and were considered candidate marker genes for tumor invasion and progression. Correlative gene expression analyses demonstrated a high percentage of them to be poor prognosis markers in early stage ADC. Quantitative PCR also validated the amplification and overexpression of PDCD6 and TERT on chromosome 5p and the prognostic significance of PDCD6 in early stage ADC patients. We identified candidate genes that may be responsible for and are potential markers for malignant progression in AWBF. Keywords: array comparitive genomic hybridization, bronchioloalveolar carcinoma, non-small-cell lung carcinoma, prognostic markers
Project description:To obtain further insights into the role of bacterial activity in BAC filter performance, the expressed proteins of the bacterial community residing in the BAC filter were identified by a metaproteomic approach.
Project description:P. aeruginosa is the leading cause of death in patients with cystic fibrosis patients and one of the most problematic bacterial pathogens responsible for hospital-acquired infections. This pathogen has a high capacity to form biofilms on inert and living surfaces. This lifestyle allows it to persist in various hospital niches or on medical device which become vectors of contamination. Chronic infections are extremely complicated to eradicate due to the remarkable antimicrobial resistance of biofilms leading to a persistence in the tissue and an immune system exhaustion. It is therefore becoming essential to understand the mechanisms of biofilm formation to find new therapeutic targets in order to develop effective antibiofilm strategies. We previously identified in P. aeruginosa PA01 biofilms an accumulation of a hypothetical protein named PA3731 and its deletion impacted the biofilm formation. Similarly, to PspA, a protein from the well-known Psp system of E. coli, PA3731 is a has a predicted structure mostly helical, a PspA/IM30 domain and was accumulated during an osmotic shock. In P. aeruginosa genome, PA3731 appears to form a cluster with 3 genes (PA3732 to PA3729) that we named BAC system for “Biofilm Associated Cluster”. Here we worked on the PA14 strain and focus our study on PA14_16140, the PA3732 homologue. Using a ∆16140 mutant and phenotypic approach, we confirmed the role of the BAC system in the virulence and biofilm formation. We added supplementary genes coding the BAC system and demonstrate that altogether they form an operonic structure regulates by RpoN. We get further insight the role PA14_16140 by proteomic quantitative approach revealing an accumulation of the BAC system proteins in ∆16140 biofilms suggesting its regulatory role of the bac operon. Moreover, we present here the first crystallographic structure of PA14_16140. To summarise, according to our studies, and although further analysis is still required, this newly discovered operon appears composed firstly of its regulator and then of a homologous PspA.
Project description:Background. As current methods for antibiotic drug discovery are being outpaced by the rise of antimicrobial resistance, new methods and innovative technologies are necessary to replenish our dwindling arsenal of antimicrobial agents. To this end, we developed the PepSAVI-MS pipeline to expedite the search for natural product bioactive peptides. Results. Herein we demonstrate expansion of PepSAVI-MS for the discovery of bacterial-sourced bioactive peptides through identification of the bacteriocin Bac-21 from Enterococcus faecalis pPD1. Minor pipeline modifications including implementation of bacteria-infused agar diffusion assays and optional digestion of peptide libraries highlight the versatility and wide adaptability of the PepSAVI-MS pipeline. Additionally, we have experimentally validated the primary protein sequence of the active, mature Bac-21 peptide for the first time and have confirmed identity with respect to primary sequence and post-translational processing. Conclusions: Successful application of PepSAVI-MS to bacterial secretomes as demonstrated herein establishes proof-of-principle for use in novel microbial bioactive peptide discovery.