, a Rosetta stone to understanding bacterial pathogenesis.

is an environmentally acquired pathogen that causes respiratory disease in humans. While the discovery of is relatively recent compared to other bacterial pathogens, over the past 50 years, has emerged as a powerhouse for studying host-pathogen interactions. In its natural habitat of fresh water, interacts with a diverse array of protozoan hosts and readily evolve to expand their host range.

Novel induction of broad-spectrum antibiotics by the human pathogen .

Unlabelled: The majority of antibiotics are natural products, with microorganism-generated molecules and their derivatives being the most prevalent source of drugs to treat infections. Thus, identifying natural products remains the most valuable resource for novel therapeutics. Here, we report the discovery of a series of dormant bacteria in honey that have bactericidal activity toward , a bacterial pathogen that causes respiratory disease in humans.

An efficient and cost-effective method for disrupting genes in RAW264.7 macrophages using CRISPR-Cas9.

The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) are widely used for genome editing in cultured cell lines. However, the implementation of genome editing is still challenging due to the complex and often costly multi-step process associated with this technique. Moreover, the efficiency of genome editing varies across cell types, often limiting utility.

Legionella pneumophila usurps host cell lipids for vacuole expansion and bacterial growth.

Vacuolar pathogens reside in membrane-bound compartments within host cells. Maintaining the integrity of this compartment is paramount to bacterial survival and replication as it protects against certain host surveillance mechanisms that function to eradicate invading pathogens. Preserving this compartment during bacterial replication requires expansion of the vacuole membrane to accommodate the increasing number of bacteria, and yet, how this is accomplished remains largely unknown.

inhibits type I interferon signaling to avoid cell-intrinsic host cell defense.

The host type I interferon (IFN) response protects against infections. Other bacterial pathogens inhibit type I IFN-mediated cell signaling; however, the interaction between this signaling pathway and has not been well described. Here, we demonstrate that inhibits the IFN-β signaling pathway but does not inhibit IFN-γ-mediated cell signaling.

Complete Genome Sequence of an African Raw Honey Bacterial Isolate, Bacillus safensis Strain AHB11.

We present the complete genome sequence of Bacillus safensis strain AHB11, which was isolated from African raw honey from Kajo Keji, South Sudan, that had been purchased from a third-party vendor. The genome is composed of a 3,697,357-bp chromosome and a 7,105-bp plasmid, collectively encompassing 3,699 predicted protein-coding sequences and 110 RNA genes.

Complete Genome Sequence of Bacillus safensis Strain AHB2, Isolated from African Raw Honey from Kajo Keji, South Sudan.

We report the complete genome sequence of Bacillus safensis strain AHB2, isolated from African raw honey originating in Kajo Keji, South Sudan, and purchased from a third-party vendor. The genome consists of 3,785,324 bp encompassing 3,774 predicted protein-coding sequences and 183 RNA genes.

Combinatorial selection in amoebal hosts drives the evolution of the human pathogen Legionella pneumophila.

Virulence mechanisms typically evolve through the continual interaction of a pathogen with its host. In contrast, it is poorly understood how environmentally acquired pathogens are able to cause disease without prior interaction with humans. Here, we provide experimental evidence for the model that Legionella pathogenesis in humans results from the cumulative selective pressures of multiple amoebal hosts in the environment.

From Many Hosts, One Accidental Pathogen: The Diverse Protozoan Hosts of .

The 1976 outbreak of Legionnaires' disease led to the discovery of the intracellular bacterial pathogen . Given their impact on human health, species and the mechanisms responsible for their replication within host cells are often studied in alveolar macrophages, the primary human cell type associated with disease. Despite the potential severity of individual cases of disease, are not spread from person-to-person.

Beyond Paralogs: The Multiple Layers of Redundancy in Bacterial Pathogenesis.

Redundancy has been referred to as a state of no longer being needed or useful. Microbiologists often theorize that the only case of true redundancy in a haploid organism would be a recent gene duplication event, prior to divergence through selective pressure. However, a growing number of examples exist where an organism encodes two genes that appear to perform the same function.

Implementation of a pediatric behavioral staffing algorithm in an acute hospital: a best practice implementation project.

Background: A progressive decline in acute psychiatric facility beds has led to a steadily increasing number of pediatric psychiatric patients hospitalized on acute care medical-surgical units. Clinical nurses in this environment feel ill-equipped to provide quality behavioral health care.

Aims/objectives: This project aimed to improve continuity of care as well as staff and patient safety in pediatric acute and transitional care units.

Iron Limitation Triggers Early Egress by the Intracellular Bacterial Pathogen Legionella pneumophila.

Legionella pneumophila is an intracellular bacterial pathogen that replicates in alveolar macrophages, causing a severe form of pneumonia. Intracellular growth of the bacterium depends on its ability to sequester iron from the host cell. In the L.

iMAD, a genetic screening strategy for dissecting complex interactions between a pathogen and its host.

Insertional mutagenesis and depletion (iMAD) is a genetic screening strategy for dissecting complex interactions between two organisms. The simultaneous genetic manipulation of both organisms allows the identification of aggravating and alleviating genetic interactions between pairs of gene disruptions, one from each organism. Hierarchial clustering and genetic interaction networks are then used to identify common behavioral patterns among subsets of genes, which allow functional relationships between proteins and their component pathways to be elucidated.

Aggravating genetic interactions allow a solution to redundancy in a bacterial pathogen.

Interactions between hosts and pathogens are complex, so understanding the events that govern these interactions requires the analysis of molecular mechanisms operating in both organisms. Many pathogens use multiple strategies to target a single event in the disease process, confounding the identification of the important determinants of virulence. We developed a genetic screening strategy called insertional mutagenesis and depletion (iMAD) that combines bacterial mutagenesis and RNA interference, to systematically dissect the interplay between a pathogen and its host.

Analysis of Legionella infection using RNAi in Drosophila cells.

RNA interference (RNAi) is the process of specific gene silencing by the use of double-stranded RNA (dsRNA). In cultured Drosophila cells, RNAi methodologies are well established and easily executed: dsRNA, when added to the cell culture medium, is efficiently internalized by the cells and, through the activity of endogenous processing machinery, targets the specified mRNA for degradation resulting in reduced levels of its encoded protein. This technique has proven very useful in studying the role of host genes during Legionella pneumophila infections, as it allows the effect of host factor depletion on intracellular growth of the bacterium to be examined.

The Legionella effector RavZ inhibits host autophagy through irreversible Atg8 deconjugation.

Eukaryotic cells can use the autophagy pathway to defend against microbes that gain access to the cytosol or reside in pathogen-modified vacuoles. It remains unclear if pathogens have evolved specific mechanisms to manipulate autophagy. Here, we found that the intracellular pathogen Legionella pneumophila could interfere with autophagy by using the bacterial effector protein RavZ to directly uncouple Atg8 proteins attached to phosphatidylethanolamine on autophagosome membranes.

Minimization of the Legionella pneumophila genome reveals chromosomal regions involved in host range expansion.

Legionella pneumophila is a bacterial pathogen of amoebae and humans. Intracellular growth requires a type IVB secretion system that translocates at least 200 different proteins into host cells. To distinguish between proteins necessary for growth in culture and those specifically required for intracellular replication, a screen was performed to identify genes necessary for optimal growth in nutrient-rich medium.

The E Block motif is associated with Legionella pneumophila translocated substrates.

Legionella pneumophila promotes intracellular growth by moving bacterial proteins across membranes via the Icm/Dot system. A strategy was devised to identify large numbers of Icm/Dot translocated proteins, and the resulting pool was used to identify common motifs that operate as recognition signals. The 3' end of the sidC gene, which encodes a known translocated substrate, was replaced with DNA encoding 200 codons from the 3' end of 442 potential substrate-encoding genes.

The Legionella pneumophila replication vacuole: making a cosy niche inside host cells.

The pathogenesis of Legionella pneumophila is derived from its growth within lung macrophages after aerosols are inhaled from contaminated water sources. Interest in this bacterium stems from its ability to manipulate host cell vesicular-trafficking pathways and establish a membrane-bound replication vacuole, making it a model for intravacuolar pathogens. Establishment of the replication compartment requires a specialized translocation system that transports a large cadre of protein substrates across the vacuolar membrane.

Members of a Legionella pneumophila family of proteins with ExoU (phospholipase A) active sites are translocated to target cells.

Legionella pneumophila replicates within alveolar macrophages, causing a severe pneumonia termed Legionnaires' disease. The bacterium resides within a vacuole that escapes immediate transport to the host lysosome. Instead, the vacuole interacts with the early secretory pathway to establish an environment suitable for rapid multiplication.

Pivotal roles for the receiver domain in the mechanism of action of the response regulator RamR of Streptomyces coelicolor.

The response regulator RamR activates expression of the ramCSAB operon, the source of the morphogenetic peptide SapB, and is therefore important for morphogenesis of the bacterium Streptomyces coelicolor. Like most response regulators, RamR consists of an amino-terminal receiver domain and a carboxy-terminal DNA binding domain. Four of five highly conserved active site residues known to be important in other response regulators are present in RamR: D12, D56 (the predicted site of phosphorylation), T84 and K105.