Project description:<p>Despite improved diagnostics, pulmonary pathogens in immunocompromised children frequently evade detection, leading to significant mortality. In this study, we performed RNA and DNA-based metagenomic next generation sequencing (mNGS) on 41 lower respiratory samples collected from 34 children. We identified a rich cross-domain pulmonary microbiome containing bacteria, fungi, RNA viruses, and DNA viruses in each patient. Potentially pathogenic bacteria were ubiquitous among samples but could be distinguished as possible causes of disease by parsing for outlier organisms. Potential pathogens were detected in half of samples previously negative by clinical diagnostics. Ongoing investigation is needed to determine the pathogenic significance of outlier microbes in the lungs of immunocompromised children with pulmonary disease. Metatranscriptomic (RNA) sequencing libraries are reported in the manuscript and are included for this release.</p>
| phs001684 | dbGaP
Project description:Lampenflora communities from Carlsbad Cavern (domain Bacteria)
Project description:TC-510 is a novel cell therapy that consists of autologous genetically engineered T cells expressing two synthetic constructs: first, a single-domain antibody that recognizes human Mesothelin, fused to the CD3-epsilon subunit which, upon expression, is incorporated into the endogenous T cell receptor (TCR) complex and second, a PD-1:CD28 switch receptor, which is expressed on the surface of the T cell, independently from the TCR. The PD-1:CD28 switch receptor comprises the PD-1 extracellular domain fused to the CD28 intracellular domain via a transmembrane domain. Thus, the switch is designed to produce a costimulatory signal upon engagement with PD-L1 on cancer cells.
Project description:Proper chromosome segregation is essential in all living organisms. The ParA-ParB-parS system is widely employed for chromosome segregation in bacteria. Previously, we showed that Caulobacter crescentus ParB requires cytidine triphosphate to escape the nucleation site parS to spread by sliding to the neighboring DNA. Here, we provide the structural basis for this transition from nucleation to spreading by solving co-crystal structures of a C-terminal domain truncated C. crescentus ParB with parS and with a CTP analog. Nucleating ParB is an open clamp, in which parS is captured at the DNA-binding domain (the DNA-gate). Upon binding CTP, the N-terminal domain (NTD) self-dimerizes to close the NTD-gate of the clamp. The DNA-gate also closes, thus driving parS into a compartment between the DNA-gate and the C-terminal domain. CTP hydrolysis and/or the release of hydrolytic products may re-open the gates. Overall, we suggest a CTP-operated gating mechanism that regulates ParB nucleation and spreading.
Project description:Transcription generates local topological and mechanical constraints along the DNA fiber, driving for instance the generation of supercoiled chromosomal domains in bacteria. However, the global impact of transcription-based regulation of chromosome organization remains elusive. Notably, the scale of genes and operons in bacteria remains well below the resolution of chromosomal contact maps generated using Hi-C (~ 5 - 10 kb), preventing to resolve the impact of transcription on genomic organization at the fine-scale. Here, we combined sub-kb Hi-C contact maps and chromosome engineering to visualize individual transcriptional units (TUs) while turning off transcription across the rest of the genome. We show that each TU forms a discrete, transcription-induced 3D domain (TIDs). These local structures impose mechanical and topological constraints on their neighboring sequences at larger scales, bringing them closer together and restricting their dynamics. These results show that the primary building blocks of bacteria chromosome folding consists of transcriptional domains that together shape the global genome structure.
Project description:Most bacteria are surrounded by a peptidoglycan cell wall composed of glycan strands held together by short peptide crosslinks. There are two major types of crosslinks, termed 4-3 and 3-3 based on the amino acids involved. 4-3 crosslinks are created by penicillin-binding proteins (PBPs), while 3-3 crosslinks created byL,D-transpeptidases (LDTs). In well studied bacteria 3-3 crosslinks comprise only about 10% of the total and are not essential. However, in the opportunistic intestinal pathogenClostridioides difficile,about 70% of the crosslinks are 3-3. We show here that 3-3 crosslinks and LDTs are essential for viability inC. difficile. We also show thatC. difficilehas five LDTs, three with a YkuD catalytic domain as in all previously known LDTs and two with a VanW catalytic domain, whose function was until now unknown. The five LDTs exhibit extensive functional redundancy. VanW domain proteins are found in many Gram-positive bacteria but scarce in other lineages. We tested seven non-C. difficileVanW domain proteins and confirmed LDT activity in three cases. In summary, our findings uncover a new family of peptidoglycan crosslinking enzymes, assign a catalytic function to VanW domains, and demonstrate that 3-3 crosslinking is essential for viability inC. difficile, the first time this has been shown in any bacterial species.
Project description:<p>Members of the Omp85 superfamily of outer membrane proteins (OMPs) found in Gram-negative bacteria, mitochondria and chloroplasts are characterized by a distinctive 16-stranded β-barrel transmembrane domain and at least one periplasmic POTRA domain. All previously studied Omp85 proteins promote critical OMP assembly and/or protein translocation reactions. Pseudomonas aeruginosa PlpD is the prototype of an Omp85 protein family that contains an N-terminal patatin-like (PL) domain that is thought to be translocated across the OM by a C-terminal β-barrel domain. Challenging the current dogma, we found that the PlpD PL-domain resides exclusively in the periplasm and, unlike previously studied Omp85 proteins, PlpD forms a homodimer. Remarkably, the PL-domain contains a segment that exhibits unprecedented dynamicity by undergoing transient strand-swapping with the neighboring β-barrel domain. Our results show that the Omp85 superfamily is more structurally diverse than currently believed and suggest that the Omp85 scaffold was utilized during evolution to generate novel functions. </p>
Project description:Bacterial nucleoid-associated proteins play important roles in chromosome organization and global gene regulation. We find that Lsr2 of Mycobacterium tuberculosis is a novel nucleoid-associated protein that specifically binds AT-rich regions of the genome, including regions encoding major virulence factors, such as the ESX secretion systems, the lipid virulence factors PDIM/PGL, and the PE/PPE families of antigenic proteins. Comparison of genome-wide binding data with expression data indicates that Lsr2 binding results in transcriptional repression. Domain swamping experiments demonstrate that Lsr2 has an N-terminal dimerization domain and a C-terminal DNA binding domain. NMR analysis of the DNA binding domain of Lsr2 and its interaction with DNA reveals a novel structure and a unique mechanism that enables Lsr2 to discriminately target AT-rich sequences through interactions with the minor groove of DNA. Taken together, we provide evidence that mycobacteria have employed a structurally distinct molecule with an apparently different DNA recognition mechanism to achieve an equivalent function as the Enterobacteriaceae H-NS, coordinating global gene regulation and virulence in this group of medically important bacteria.
Project description:Background: Probiotic-like bacteria treatment has been described to be associated with gut microbiota modifications. Goal: To decipher if the effects of the tested probiotic-like bacteria are due to the bacteria itself or due to the effects of the bacteria on the gut microbiota. Methodology: In this study, gut microbiota has been analyzed from feces samples of subjects with metabolic syndrome and treated with one of the 2 tested probiotic-like bacteria or with the placebo during 3months.