A Complete Genome of the Alphaproteobacterial Methanotroph Methylocystis parvus OBBP.

A complete genome is presented for Methylocystis parvus OBBP, a Gram-negative aerobic methanotroph of the phylum . OBBP is the genus type strain and of interest in the production of polyhydroxybutyrate and environmental microbiology. The genome consists of two plasmids (248 kbp and 205 kbp) and a chromosome (4.

In Vivo Genome Editing in Type I and II Methanotrophs Using a CRISPR/Cas9 System.

Methanotrophic bacteria are Gram-negative, aerobic organisms that use methane as their sole source of carbon and energy. In this study, we constructed and exemplified a CRISPR/Cas9 genome editing system and used it to successfully make gene deletions and insertions in the type I methanotroph Bath and the type II methanotroph OBBP. High frequencies of gene deletions and insertions were achieved in combination with homology-directed repair.

Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks.

Waste plastic and methane emissions are two anthropogenic by-products exacerbating environmental pollution. Methane-oxidizing bacteria (methanotrophs) hold the key to solving these problems simultaneously by utilising otherwise wasted methane gas as carbon source and accumulating the carbon as poly-3-hydroxybutyrate, a biodegradable plastic polymer. Here we present the isolation and characterisation of two novel Methylocystis strains with the ability to produce up to 55.

A Coxiella burnetii phospholipase A homolog pldA is required for optimal growth in macrophages and developmental form lipid remodeling.

Background: Many gram-negative bacteria produce an outer membrane phospholipase A (PldA) that plays an important role in outer membrane function and is associated with virulence.

Results: In the current study, we characterized a pldA mutant of Coxiella burnetii, an intracellular gram-negative pathogen and the agent of human Q fever. The C.

Sec-mediated secretion by Coxiella burnetii.

Background: Coxiella burnetii is a Gram-negative intracellular bacterial pathogen that replicates within a phagolysosome-like parasitophorous vacuole (PV) of macrophages. PV formation requires delivery of effector proteins directly into the host cell cytoplasm by a type IVB secretion system. However, additional secretion systems are likely responsible for modification of the PV lumen microenvironment that promote pathogen replication.

Dot/Icm type IVB secretion system requirements for Coxiella burnetii growth in human macrophages.

Central to Q fever pathogenesis is replication of the causative agent, Coxiella burnetii, within a phagolysosome-like parasitophorous vacuole (PV) in mononuclear phagocytes. C. burnetii modulates PV biogenesis and other host cell functions, such as apoptotic signaling, presumably via the activity of proteins delivered to the host cytosol by a Dot/Icm type IVB secretion system (T4BSS).

Development of reagents and assays for the detection of pathogenic Burkholderia species.

Rapid detection of the category B biothreat agents Burkholderia pseudomallei and Burkholderia mallei in acute infections is critical to ensure that appropriate treatment is administered quickly to reduce an otherwise high probability of mortality (ca. 40% for B. pseudomallei).

Removal of the outer Kdo from Helicobacter pylori lipopolysaccharide and its impact on the bacterial surface.

Helicobacter pylori produces a unique surface lipopolysaccharide (LPS) characterized by strikingly low endotoxicity that is thought to aid the organism in evading the host immune response. This reduction in endotoxicity is predicted to arise from the modification of the Kdo-lipid A domain of Helicobacter LPS by a series of membrane bound enzymes including a Kdo (3-deoxy-d-manno-octulosonic acid) hydrolase responsible for the modification of the core oligosaccharide. Here, we report that Kdo hydrolase activity is dependent upon a putative two-protein complex composed of proteins Hp0579 and Hp0580.

Active-site architecture and catalytic mechanism of the lipid A deacylase LpxR of Salmonella typhimurium.

The lipid A portion of lipopolysaccharide, the major component of the outer leaflet of the outer membrane of gram-negative bacteria, is toxic to humans. Modification of lipid A by enzymes often reduces its toxicity. The outer-membrane protein LpxR from Salmonella typhimurium is a lipid A-modifying enzyme.

Deciphering the unusual acylation pattern of Helicobacter pylori lipid A.

The synthesis of "typical" hexa-acylated lipid A occurs via a nine-step enzymatic pathway, which is generally well conserved throughout all gram-negative bacteria. One exception to the rule is Helicobacter pylori, which has only eight homologs to the nine lipid A biosynthetic enzymes. The discrepancy occurs toward the end of the pathway, with H.

Diversity of endotoxin and its impact on pathogenesis.

Lipopolysaccharide or LPS is localized to the outer leaflet of the outer membrane and serves as the major surface component of the bacterial cell envelope. This remarkable glycolipid is essential for virtually all Gram-negative organisms and represents one of the conserved microbial structures responsible for activation of the innate immune system. For these reasons, the structure, function, and biosynthesis of LPS has been an area of intense research.

The Pseudomonas aeruginosa lipid A deacylase: selection for expression and loss within the cystic fibrosis airway.

Lipopolysaccharide (LPS) is the major surface component of gram-negative bacteria, and a component of LPS, lipid A, is recognized by the innate immune system through the Toll-like receptor 4/MD-2 complex. Pseudomonas aeruginosa, an environmental gram-negative bacterium that opportunistically infects the respiratory tracts of patients with cystic fibrosis (CF), can synthesize various structures of lipid A. Lipid A from P.

Resistance to the antimicrobial peptide polymyxin requires myristoylation of Escherichia coli and Salmonella typhimurium lipid A.

Attachment of positively charged, amine-containing residues such as 4-amino-4-deoxy-l-arabinose (l-Ara4N) and phosphoethanolamine (pEtN) to Escherichia coli and Salmonella typhimurium lipid A is required for resistance to the cationic antimicrobial peptide, polymyxin. In an attempt to discover additional lipid A modifications important for polymyxin resistance, we generated polymyxin-sensitive mutants of an E. coli pmrA(C) strain, WD101.

Remodeling of Helicobacter pylori lipopolysaccharide.

Modification of the lipid A domain of lipopolysaccharide (LPS) has been reported to contribute to the virulence and pathogenesis of various Gram-negative bacteria. The Kdo (3-deoxy-D-manno-octulosonic acid)-lipid A domain of Helicobacter pylori LPS shows several differences to that of Escherichia coli. It has fewer acyl chains, a reduced number of phosphate groups, much lower immunobiological activity, and only a single Kdo sugar is attached to the disaccharide backbone.

A novel 3-deoxy-D-manno-octulosonic acid (Kdo) hydrolase that removes the outer Kdo sugar of Helicobacter pylori lipopolysaccharide.

The lipid A domain anchors lipopolysaccharide (LPS) to the outer membrane and is typically a disaccharide of glucosamine that is both acylated and phosphorylated. The core and O-antigen carbohydrate domains are linked to the lipid A moiety through the eight-carbon sugar 3-deoxy-D-manno-octulosonic acid known as Kdo. Helicobacter pylori LPS has been characterized as having a single Kdo residue attached to lipid A, predicting in vivo a monofunctional Kdo transferase (WaaA).