Metabolomic and Lipidomic Profiling of Using Two-Dimensional Tandem Mass Spectrometry.

Lipidomic and metabolomic profiles of sporulated and vegetative and from irradiated lysates were recorded using a quadrupole ion trap mass spectrometer modified to perform two-dimensional tandem mass spectrometry (2D MS/MS). The 2D MS/MS data domains, acquired using a 1.2 s scan of negative ions generated by nanoelectrospray ionization of microwave irradiated spores, showed the presence of dipicolinic acid (DPA) as well as various lipids.

In vivo demonstration of Pseudomonas aeruginosa biofilms as independent pharmacological microcompartments.

Background: Pseudomonas aeruginosa is difficult to eradicate from the lungs of cystic fibrosis (CF) patients due to biofilm formation. Organs and blood are independent pharmacokinetic (PK) compartments. Previously, we showed in vitro biofilms behave as independent compartments impacting the pharmacodynamics.

Three-Dimensional Super-Resolution Imaging Using a Row-Column Array.

A 3-D super-resolution (SR) pipeline based on data from a row-column (RC) array is presented. The 3-MHz RC array contains 62 rows and 62 columns with a half wavelength pitch. A synthetic aperture (SA) pulse inversion sequence with 32 positive and 32 negative row emissions is used for acquiring volumetric data using the SARUS research ultrasound scanner.

Formation of Pseudomonas aeruginosa inhibition zone during tobramycin disk diffusion is due to transition from planktonic to biofilm mode of growth.

Pseudomonas aeruginosa PAO1 (tobramycin MIC = 0.064 µg/mL) was used to perform agar diffusion tests employing tobramycin-containing tablets. Bacterial growth and formation of inhibition zones were studied by stereomicroscopy and by blotting with microscope slides and staining with methylene blue, Alcian blue and a fluorescent lectin for the P.

Modelling of ciprofloxacin killing enhanced by hyperbaric oxygen treatment in Pseudomonas aeruginosa PAO1 biofilms.

Outline: In chronic lung infections by Pseudomonas aeruginosa (PA) the bacteria thrive in biofilm structures protected from the immune system of the host and from antibiotic treatment. Increasing evidence suggests that the susceptibility of the bacteria to antibiotic treatment can be significantly enhanced by hyperbaric oxygen treatment. The aim of this study is to simulate the effect of ciprofloxacin treatment in a PAO1 biofilm model with aggregates in agarose when combined with hyperbaric oxygen treatment.

Reconstructing Dynamic Promoter Activity Profiles from Reporter Gene Data.

Accurate characterization of promoter activity is important when designing expression systems for systems biology and metabolic engineering applications. Promoters that respond to changes in the environment enable the dynamic control of gene expression without the necessity of inducer compounds, for example. However, the dynamic nature of these processes poses challenges for estimating promoter activity.

Hyperbaric Oxygen Sensitizes Anoxic Pseudomonas aeruginosa Biofilm to Ciprofloxacin.

Chronic lung infection is characterized by the presence of endobronchial antibiotic-tolerant biofilm, which is subject to strong oxygen (O) depletion due to the activity of surrounding polymorphonuclear leukocytes. The exact mechanisms affecting the antibiotic susceptibility of biofilms remain unclear, but accumulating evidence suggests that the efficacy of several bactericidal antibiotics is enhanced by stimulation of aerobic respiration of pathogens, while lack of O increases their tolerance. In fact, the bactericidal effect of several antibiotics depends on active aerobic metabolism activity and the endogenous formation of reactive O radicals (ROS).

How fast is a collective bacterial state established?

Bacteria in a biofilm colony have the capacity to monitor the size and growth conditions for the colony and modify their phenotypical behaviour to optimise attacks, defence, migration, etc. The quorum sensing systems controlling this involve production and sensing of diffusive signal molecules. Frequently, quorum sensing systems carry a positive feedback loop which produces a switch at a threshold size of the colony.

High-resolution kinetics and modeling of hydrogen peroxide degradation in live cells.

Although the role of oxidative stress factors and their regulation is well studied, the temporal dynamics of stress recovery is still poorly understood. In particular, measuring the kinetics of stress recovery in the first minutes after acute exposure provides a powerful technique for assessing the role of regulatory proteins or enzymes through the use of mutant backgrounds. This project endeavors to screen the temporal dynamics of intracellular oxidant levels in live cells as a function of gene deletion in the budding yeast, Saccharomyces cerevisiae.

Diffusion Retardation by Binding of Tobramycin in an Alginate Biofilm Model.

Microbial cells embedded in a self-produced extracellular biofilm matrix cause chronic infections, e. g. by Pseudomonas aeruginosa in the lungs of cystic fibrosis patients.

Reinforcement of the bactericidal effect of ciprofloxacin on Pseudomonas aeruginosa biofilm by hyperbaric oxygen treatment.

Chronic Pseudomonas aeruginosa lung infection is the most severe complication in cystic fibrosis patients. It is characterised by antibiotic-tolerant biofilms in the endobronchial mucus with zones of oxygen (O2) depletion mainly due to polymorphonuclear leucocyte activity. Whilst the exact mechanisms affecting antibiotic effectiveness on biofilms remain unclear, accumulating evidence suggests that the efficacy of several bactericidal antibiotics such as ciprofloxacin is enhanced by stimulation of the aerobic respiration of pathogens, and that lack of O2 increases their tolerance.

Microbial biofilm as a smart material.

Microbial biofilm colonies will in many cases form a smart material capable of responding to external threats dependent on their size and internal state. The microbial community accordingly switches between passive, protective, or attack modes of action. In order to decide which strategy to employ, it is essential for the biofilm community to be able to sense its own size.

Video surveillance of epilepsy patients using color image processing.

This paper introduces a method for tracking patients under video surveillance based on a color marker system. The patients are not restricted in their movements, which requires a tracking system that can overcome non-ideal scenes e.g.

Size of quorum sensing communities.

Ensembles of bacteria are able to coordinate their phenotypic behavior in accordance with the size, density, and growth state of the ensemble. This is achieved through production and exchange of diffusible signal molecules in a cell-cell regulatory system termed quorum sensing. In the generic quorum sensor a positive feedback in the production of signal molecules defines the conditions at which the collective behavior switches on.

Kinetic model for signal binding to the Quorum sensing regulator LasR.

We propose a kinetic model for the activation of the las regulon in the opportunistic pathogen Pseudomonas aeruginosa. The model is based on in vitro data and accounts for the LasR dimerization and consecutive activation by binding of two OdDHL signal molecules. Experimentally, the production of the active LasR quorum-sensing regulator was studied in an Escherichia coli background as a function of signal molecule concentration.

Ligand binding kinetics of the quorum sensing regulator PqsR.

The Pseudomonas aeruginosa quinolone signal (PQS) is a quorum sensing molecule that plays an important role in regulating the virulence of this organism. We have purified the ligand binding domain of the receptor PqsRLBD for PQS and have used Förster resonance energy transfer fluorimetry and kinetic modeling to characterize the ligand binding in vitro. The dissociation constant for binding of PQS to a ligand binding site in (PqsRLBD)2 dimers was determined to be 1.

Seizure onset detection based on one sEMG channel.

We present a new method to detect seizure onsets of tonic-clonic epileptic seizures based on surface electromyography (sEMG) data. The proposed method is generic and based on a single channel making it ideal for a small detection or monitoring device. The sEMG signal is high-pass filtered with a Butterworth filter with a cut-off frequency of 150 Hz.

Patterns of muscle activation during generalized tonic and tonic-clonic epileptic seizures.

Purpose: Tonic seizures and the tonic phase of tonic-clonic epileptic seizures are defined as "sustained tonic" muscle contraction lasting a few seconds to minutes. Visual inspection of the surface electromyogram (EMG) during seizures contributed considerably to a better understanding and accurate diagnosis of several seizure types. However, quantitative analysis of the surface EMG during the epileptic seizures has received surprisingly little attention until now.

Automatic multi-modal intelligent seizure acquisition (MISA) system for detection of motor seizures from electromyographic data and motion data.

The objective is to develop a non-invasive automatic method for detection of epileptic seizures with motor manifestations. Ten healthy subjects who simulated seizures and one patient participated in the study. Surface electromyography (sEMG) and motion sensor features were extracted as energy measures of reconstructed sub-bands from the discrete wavelet transformation (DWT) and the wavelet packet transformation (WPT).

Seizure onset detection based on a Uni- or multi-modal intelligent seizure acquisition (UISA/MISA) system.

An automatic Uni- or Multi-modal Intelligent Seizure Acquisition (UISA/MISA) system is highly applicable for onset detection of epileptic seizures based on motion data. The modalities used are surface electromyography (sEMG), acceleration (ACC) and angular velocity (ANG). The new proposed automatic algorithm on motion data is extracting features as "log-sum" measures of discrete wavelet components.

Quorum sensing regulation in Aeromonas hydrophila.

We present detailed results on the C4-HSL-mediated quorum sensing (QS) regulatory system of the opportunistic Gram-negative bacterium Aeromonas hydrophila. This bacterium contains a particularly simple QS system that allows for a detailed modeling of kinetics. In a model system (i.

Multi-modal intelligent seizure acquisition (MISA) system--a new approach towards seizure detection based on full body motion measures.

Many epilepsy patients cannot call for help during a seizure, because they are unconscious or because of the affection of their motor system or speech function. This can lead to injuries, medical complications and at worst death. An alarm system setting off at seizure onset could help to avoid hazards.

Sand ripples under water with complex wave motion.

Experiments studying ripple formation under water have usually used sinusoidal driving force. Here an experiment is presented where the driving force can be an arbitrary wave form, thus trying to mimic the realistic wave motion in shallow water coastal zones. We study a simple modulated sine wave and more complicated wave forms with several superposed harmonics.