The origin of 8-amino-3,8-dideoxy-D-manno-octulosonic acid (Kdo8N) in the lipopolysaccharide of Shewanella oneidensis.

Lipopolysaccharide (LPS; endotoxin) is an essential component of the outer monolayer of nearly all Gram-negative bacteria. LPS is composed of a hydrophobic anchor, known as lipid A, an inner core oligosaccharide, and a repeating O-antigen polysaccharide. In nearly all species, the first sugar bridging the hydrophobic lipid A and the polysaccharide domain is 3-deoxy-d-manno-octulosonic acid (Kdo), and thus it is critically important for LPS biosynthesis.

Virulence and stress-related periplasmic protein (VisP) in bacterial/host associations.

Gram-negative bacteria have an outer membrane containing LPS. LPS is constituted of an oligosaccharide portion and a lipid-A moiety that embeds this molecule within the outer membrane. LPS is a pathogen-associated molecular pattern, and several pathogens modify their lipid-A as a stealth strategy to avoid recognition by the innate immune system and gain resistance to host factors that disrupt the bacterial cell envelope.

The outer membrane of Gram-negative bacteria: lipid A isolation and characterization.

The isolation and characterization of the lipid A domain of lipopolysaccharide (LPS) are important methodologies utilized to gain understanding of the Gram-negative cell envelope. Here, we describe protocols often employed by our laboratory for small- and large-scale isolation of lipid A from bacterial cells. Additionally, we describe various methodologies including isolation of radiolabeled lipid A, thin layer chromatography, and various mass spectrometry methods.

Modulating the innate immune response by combinatorial engineering of endotoxin.

Despite its highly inflammatory nature, LPS is a molecule with remarkable therapeutic potential. Lipid A is a glycolipid that serves as the hydrophobic anchor of LPS and constitutes a potent ligand of the Toll-like receptor (TLR)4/myeloid differentiation factor 2 receptor of the innate immune system. A less toxic mixture of monophosphorylated lipid A species (MPL) recently became the first new Food and Drug Administration-approved adjuvant in over 70 y.

The polysaccharide capsule of Campylobacter jejuni modulates the host immune response.

Campylobacter jejuni is a major cause of bacterial diarrheal disease worldwide. The organism is characterized by a diversity of polysaccharide structures, including a polysaccharide capsule. Most C.

EptC of Campylobacter jejuni mediates phenotypes involved in host interactions and virulence.

Campylobacter jejuni is a natural commensal of the avian intestinal tract. However, the bacterium is also the leading cause of acute bacterial diarrhea worldwide and is implicated in development of Guillain-Barré syndrome. Like many bacterial pathogens, C.

The Pseudomonas aeruginosa PhoP-PhoQ two-component regulatory system is induced upon interaction with epithelial cells and controls cytotoxicity and inflammation.

The adaptation of Pseudomonas aeruginosa to its environment, including the host, is tightly controlled by its network of regulatory systems. The two-component regulatory system PhoPQ has been shown to play a role in the virulence and polymyxin resistance of P. aeruginosa as well as several other Gram-negative species.

Amino acid addition to Vibrio cholerae LPS establishes a link between surface remodeling in gram-positive and gram-negative bacteria.

Historically, the O1 El Tor and classical biotypes of Vibrio cholerae have been differentiated by their resistance to the antimicrobial peptide polymyxin B. However, the molecular mechanisms associated with this phenotypic distinction have remained a mystery for 50 y. Both gram-negative and gram-positive bacteria modify their cell wall components with amine-containing substituents to reduce the net negative charge of the bacterial surface, thereby promoting cationic antimicrobial peptide resistance.

Desire for pregnancy and risk behavior in young HIV-positive women.

This cross-sectional study utilized data from 130 young women with behaviorally acquired HIV to examine the association between desire for pregnancy (DFP) and both sociodemographic variables and sexual risk behaviors. A single item was utilized to assess DFP. Bivariate and multivariate regression analyses were conducted.

Helicobacter pylori versus the host: remodeling of the bacterial outer membrane is required for survival in the gastric mucosa.

Modification of bacterial surface structures, such as the lipid A portion of lipopolysaccharide (LPS), is used by many pathogenic bacteria to help evade the host innate immune response. Helicobacter pylori, a gram-negative bacterium capable of chronic colonization of the human stomach, modifies its lipid A by removal of phosphate groups from the 1- and 4'-positions of the lipid A backbone. In this study, we identify the enzyme responsible for dephosphorylation of the lipid A 4'-phosphate group in H.

Characterization of unique modification of flagellar rod protein FlgG by Campylobacter jejuni lipid A phosphoethanolamine transferase, linking bacterial locomotion and antimicrobial peptide resistance.

Gram-negative bacteria assemble complex surface structures that interface with the surrounding environment and are involved in pathogenesis. Recent work in Campylobacter jejuni identified a gene encoding a novel phosphoethanolamine (pEtN) transferase Cj0256, renamed EptC, that serves a dual role in modifying the flagellar rod protein, FlgG, and the lipid A domain of C. jejuni lipooligosaccharide with a pEtN residue.

Adolescent and parental utilities for the health states associated with pelvic inflammatory disease.

Purpose: There is limited information about how the consumers of adolescent pelvic inflammatory disease (PID) care value health states associated with the disorder. The aim of this study is to determine and compare adolescent and parent PID-related health utilities.

Methods: Adolescent girls (N=134) and parents (N=121) completed a web-based utility elicitation survey.

Recurrent PID, subsequent STI, and reproductive health outcomes: findings from the PID evaluation and clinical health (PEACH) study.

PEACH trial data were used to evaluate the relationship between subsequent sexually transmitted infection and recurrent pelvic inflammatory disease on infertility and chronic pelvic pain (CPP). Recurrent pelvic inflammatory disease was associated with an almost 2-fold increase in infertility and more than 4-fold increase in CPP. Subsequent sexually transmitted infection was associated with CPP, but not infertility.

Childbearing motivations, pregnancy desires, and perceived partner response to a pregnancy among urban female youth: does HIV-infection status make a difference?

Despite a growing literature assessing pregnancy desires among HIV-infected women enrolled in clinical care, little attention has been paid to HIV-infected youth for whom pregnancy is a very relevant issue. In urban areas with high rates of teen pregnancy and HIV infection, further understanding of childbearing motivations and relationship dynamics influencing pregnancy desires among female youth is needed. This study compares the childbearing motivations, pregnancy desires, and perceived partner desire for a pregnancy among predominately African-American HIV-infected (n=46) and HIV-uninfected (n=355) female youth (15-24 years).

Elucidation of a novel Vibrio cholerae lipid A secondary hydroxy-acyltransferase and its role in innate immune recognition.

Similar to most Gram-negative bacteria, the outer leaflet of the outer membrane of Vibrio cholerae is comprised of lipopolysaccharide. Previous reports have proposed that V. cholerae serogroups O1 and O139 synthesize structurally different lipid A domains, which anchor lipopolysaccharide within the outer membrane.

The pmrCAB operon mediates polymyxin resistance in Acinetobacter baumannii ATCC 17978 and clinical isolates through phosphoethanolamine modification of lipid A.

The emergence of multidrug resistance among Acinetobacter baumannii is leading to an increasing dependence on the use of polymyxins as last-hope antibiotics. Here, we utilized genetic and biochemical methods to define the involvement of the pmrCAB operon in polymyxin resistance in this organism. Sequence analysis of 16 polymyxin B-resistant strains, including 6 spontaneous mutants derived from strain ATCC 17978 and 10 clinical isolates from diverse sources, revealed that they had independent mutations in the pmrB gene, encoding a sensor kinase, or in the response regulator PmrA.

IR and UV photodissociation as analytical tools for characterizing lipid A structures.

The utility of 193-nm ultraviolet photodissociation (UVPD) and 10.6-μm infrared multiphoton dissociation (IRMPD) for the characterization of lipid A structures was assessed in an ion trap mass spectrometer. The fragmentation behavior of lipid A species was also evaluated by activated-electron photodetachment (a-EPD), which uses 193-nm photons to create charge reduced radicals that are subsequently dissociated by collisional activation.

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).

Remodelling of the Vibrio cholerae membrane by incorporation of exogenous fatty acids from host and aquatic environments.

The Gram-negative bacteria Vibrio cholerae poses significant public health concerns by causing an acute intestinal infection afflicting millions of people each year. V. cholerae motility, as well as virulence factor expression and outer membrane protein production, has been shown to be affected by bile.

Adverse adolescent reproductive health outcomes after pelvic inflammatory disease.

Objective: To compare longitudinal adolescent and adult reproductive outcomes after pelvic inflammatory disease (PID).

Design: Secondary analysis of longitudinal data from the Pelvic Inflammatory Disease Evaluation and Clinical Health study.

Setting: A large multicenter randomized clinical trial assessing PID treatment strategies in the United States.

Estimating the direct costs of pelvic inflammatory disease in adolescents: a within-system analysis.

We used 2008-2009 physician and hospital charges to estimate the direct cost of medical care per case of pelvic inflammatory disease. The estimated average total charge per episode was $3,025 (SD: $4155). The estimated average charge for patients treated in ambulatory (outpatient clinic and emergency department) settings was $7440 lower than for those treated on inpatient units.

Why do women use intimate partner violence? A systematic review of women's motivations.

Studies report that women use as much or more physical intimate partner violence (IPV) as men. Most of these studies measure IPV by counting the number of IPV acts over a specified time period, but counting acts captures only one aspect of this complex phenomenon. To inform interventions, women's motivations for using IPV must be understood.

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.