Publications by authors named "Lars Fieseler"

Ropy bread spoilage caused by aerobic spore-forming bacteria (ASF) is characterized by discoloration, sticky and stringy crumb degradation, and a fruity odor due to the release of volatile organic compounds (VOCs). Previous studies employing model experiments have demonstrated strain-specific spoilage potential. However, to gain a deeper understanding, it is essential to study rope spoilage within baked bread.

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Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen with 6,534 annual reported cases in the EU in 2021. This pathotype generally contains strains with smooth LPS with O-antigen serogroup O157 being the predominant serogroup in the US. However, non-O157 STEC serogroups are becoming increasingly prevalent.

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Aerobic spore-forming (ASF) bacteria have been reported to cause ropiness in bread. Sticky and stringy degradation, discoloration, and an odor reminiscent of rotting fruit are typical characteristics of ropy bread spoilage. In addition to economic losses, ropy bread spoilage may lead to health risks, as virulent strains of ASF bacteria are not uncommon.

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Background: The interaction between bacteriophages and their hosts is intricate and highly specific. Receptor-binding proteins (RBPs) of phages such as tail fibers and tailspikes initiate the infection process. These RBPs bind to diverse outer membrane structures, including the O-antigen, which is a serogroup-specific sugar-based component of the outer lipopolysaccharide layer of Gram-negative bacteria.

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Background: The NEMIS N-Light™ Salmonella Risk method uses chemiluminescence designed for the qualitative detection of Salmonella spp. from environmental surface samples.

Objective: To validate the N-Light Salmonella Risk assay using independent and method developer validation studies according to the AOAC Performance Tested MethodsSM (PTM) program for the detection of Salmonella spp.

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As bread is a very important staple food, its spoilage threatens global food security. Ropy bread spoilage manifests in sticky and stringy degradation of the crumb, slime formation, discoloration, and an odor reminiscent of rotting fruit. Increasing consumer demand for preservative-free products and global warming may increase the occurrence of ropy spoilage.

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Broad application of antibiotics gave rise to increasing numbers of antibiotic resistant bacteria. Therefore, effective alternatives are currently investigated. Bacteriophages, natural predators of bacteria, could work as such an alternative.

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Bacteriophages are highly selective in targeting bacteria. This selectivity relies on the specific adsorption of phages to the host cell surface. In this study, a Tn5 transposon mutant library of Erwinia amylovora, the causative agent of fire blight, was screened to identify bacterial receptors required for infection by the podovirus S6.

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Shiga toxin producing Escherichia coli (STEC) are common etiological agents of food borne illnesses and outbreaks, most often caused by consuming contaminated beef products, followed by raw vegetables and dairy products. Patients infected with E. coli O157 are more likely hospitalized than patients infected with non-O157 STEC, making E.

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Background: The NEMIS Technologies N-LightTM L. monocytogenes assay uses chemiluminescence designed for the qualitative detection of Listeria monocytogenes from environmental surface samples.

Objective: To validate the NEMIS Technologies N-Light L.

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Article Synopsis
  • Methicillin-resistant Staphylococcus aureus (MRSA) can lead to serious infections, and its resistance to antibiotics makes treatment challenging, prompting the exploration of alternative methods.
  • Researchers isolated a bacteriophage targeting a specific MRSA strain, which demonstrated effective lytic activity without causing resistant strains to emerge.
  • Genetic studies identified a lysin gene within the bacteriophage, which may aid in developing targeted therapies against MRSA strains using bacteriophages and their enzymes.
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In order to prevent microbial contamination of food, monitoring of the production environment, together with the rapid detection of foodborne pathogens have proven to be of utmost importance for Food Safety. Environmental monitoring should detect harmful pathogens at the earliest point in time in order for the necessary interventions to be taken. However, current detection methods fall short with regards to speed, ease of use, and cost.

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Bacteriophages of the family often exhibit so-called depolymerases as structural components of the virion. These enzymes appear as tail spike proteins (TSPs). After specific binding to capsular polysaccharides (CPS), exopolysaccharides (EPS) or lipopolysaccharide (LPS) of the host bacteria, polysaccharide-repeating units are specifically cleaved.

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Detection of Salmonella and L. monocytogenes in food samples by current diagnostic methods requires relatively long time to results (2-6 days). Furthermore, the ability to perform environmental monitoring at the factory site for these pathogens is limited due to the need for laboratory facilities.

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Phages vB_EcoM-EP75 (EP75) and vB_EcoP-EP335 (EP335) specifically infect Shiga toxin (Stx)-producing (STEC) O157 strains. EP75 has a genome size of 158,143 bp and belongs to the genus The genome size of EP335 is 76,622 bp, and it belongs to the genus .

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Bacteriophages represent a promising alternative for controlling pathogenic bacteria. They are ubiquitous in the environment, and their isolation is usually simple and fast. However, not every phage is suitable for biocontrol applications.

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Phages vB_EamP-S2 (S2) and vB_EamM-Bue1 (Bue1) infect the plant pathogen Erwinia amylovora. S2 has a genome size of 45,495 bp and belongs to the genus SP6virus. The genome size of Bue1, related to Salmonella phage Vil, is 164,037 bp.

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To date, a small number of jumbo myoviruses have been reported to possess atypical whisker-like structures along the surface of their contractile tails. Erwinia amylovora phage vB_EamM_Y3 is another example. It possesses a genome of 261,365 kbp with 333 predicted ORFs.

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Wall teichoic acids (WTAs) are the most abundant glycopolymers found on the cell wall of many Gram-positive bacteria, whose diverse surface structures play key roles in multiple biological processes. Despite recent technological advances in glycan analysis, structural elucidation of WTAs remains challenging due to their complex nature. Here, we employed a combination of ultra-performance liquid chromatography-coupled electrospray ionization tandem-MS/MS and NMR to determine the structural complexity of WTAs from species.

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To enable specific and tightly controlled gene expression both in vitro and during the intracellular lifecycle of the pathogen Listeria monocytogenes, a TetR-dependent genetic induction system was developed. Highest concentration of cytoplasmic TetR and best repression of tetO-controlled genes was obtained by tetR expression from the synthetic promoter Pt . Anhydrotetracycline (ATc) as inducer permitted concentration-dependent, fine-tuned expression of genes under control of the tetO operator and a suitable promoter.

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is the causative agent of fire blight, a devastating plant disease affecting members of the Alternatives to antibiotics for control of fire blight symptoms and outbreaks are highly desirable, due to increasing drug resistance and tight regulatory restrictions. Moreover, the available diagnostic methods either lack sensitivity, lack speed, or are unable to discriminate between live and dead bacteria. Owing to their extreme biological specificity, bacteriophages are promising alternatives for both aims.

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Bacteriophages have regained much attention as biocontrol agents against bacterial pathogens. However, with respect to stability, phages are biomolecules and are therefore sensitive to a number of environmental influences. UV-irradiation can readily inactivate phage infectivity, which impedes their potential application in the plant phyllosphere.

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To monitor dominant species of lactic acid bacteria during cocoa bean fermentation, i.e. Lactobacillus plantarum and Lactobacillus fermentum, a fast and reliable culture-independent qPCR assay was developed.

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Listeria monocytogenes can grow as a saphrophyte in diverse habitats, e.g., soil, rivers, lakes, and on decaying plant material.

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The depolymerase enzyme (DpoL1) encoded by the T7-like phage L1 efficiently degrades amylovoran, an important virulence factor and major component of the extracellular polysaccharide (EPS) of its host, the plant pathogen Erwinia amylovora. Mass spectrometry analysis of hydrolysed EPS revealed that DpoL1 cleaves the galactose-containing backbone of amylovoran. The enzyme is most active at pH 6 and 50°C, and features a modular architecture.

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