Entity

Time filter

Source Type


Ronning H.T.,Norwegian University of Life Sciences | Madslien E.H.,Forsvarets Forskningsinstitutt FFI | Asp T.N.,Norwegian University of Life Sciences | Granum P.E.,Norwegian University of Life Sciences
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2015

Lichenysin produced by 53 different Bacillus licheniformis strains has been structurally examined with a qualitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using quadrupole-time-of-flight mass spectrometry. The same lichenysin isoforms are produced from all strains, indicating that the growth conditions have a stronger influence on the lipopeptide production than the genotype. A rapid method for the quantification of lichenysin from bacterial cell cultures with LC-MS/MS after a simple methanol extraction has been refined. For the first time commercially available lichenysin has been used as calibrant, making quantification more accurate. The trueness for C15-lichenysin has been improved to 94% using matrix-matched calibration with lichenysin compared with 30% using solvent calibration with surfactin. The quantitative method was fully validated based on Commission Decision 2002/657/EC. The LOD of the method was below 1 µg g– 1 and the repeatability ranged from 10% to 16%. © 2015 Taylor & Francis.


Borch-Pedersen K.,Norwegian University of Life Sciences | Lindback T.,Norwegian University of Life Sciences | Madslien E.H.,Norwegian University of Life Sciences | Madslien E.H.,Forsvarets Forskningsinstitutt FFI | And 4 more authors.
Applied and Environmental Microbiology | Year: 2016

When nutrients are scarce, Bacillus species form metabolically dormant and extremely resistant spores that enable survival over long periods of time under conditions not permitting growth. The presence of specific nutrients triggers spore germination through interaction with germinant receptors located in the spore's inner membrane. Bacillus licheniformis is a biotechnologically important species, but it is also associated with food spoilage and food-borne disease. The B. licheniformis ATCC 14580/ DSM13 genome exhibits three gerA family operons (gerA, gerK, and ynd) encoding germinant receptors. We show that spores of B. licheniformis germinate efficiently in response to a range of different single L-amino acid germinants, in addition to a weak germination response seen with D-glucose. Mutational analyses revealed that the GerA and Ynd germination receptors function cooperatively in triggering an efficient germination response with single L-amino acid germinants, whereas the GerK germination receptor is essential for germination with D-glucose. Mutant spores expressing only GerA and GerK or only Ynd and GerK show reduced or severely impaired germination responses, respectively, with single L-amino acid germinants. Neither GerA nor Ynd could function alone in stimulating spore germination. Together, these results functionally characterize the germination receptor operons present in B. licheniformis. We demonstrate the overlapping germinant recognition patterns of the GerA and Ynd germination receptors and the cooperative functionalities between GerA, Ynd, and GerK in inducing germination. © 2016, American Society for Microbiology.


Maseng T.,Forsvarets Forskningsinstitutt FFI
IFIP Wireless Days | Year: 2011

By applying information theory to the analysis of a cellular system, it has been shown that it is a useful idea to reuse all the frequency bands in the adjacent cell (frequency reuse factor 1) and use the most robust modulation scheme at the cell boundary. This is not a surprising result since this is done in LTE and other systems like WIMAX and DTT. How this was derived by means of simple formulas is hopefully original and should provide some useful insights. The analysis has been done for the up link which is normally more critical than down link. As expected, the capacity of the cell increases as the propagation exponent increases since there is less interference between the cells using the same frequency and only the interference from other cells using the same frequency limits the capacity - not the thermal noise. The analysis presented is not limited to a particular system like LTE. © 2011 IEEE.


Madslien E.H.,Forsvarets Forskningsinstitutt FFI | Madslien E.H.,Norwegian University of Life Sciences | Granum P.E.,Norwegian University of Life Sciences | Blatny J.M.,Forsvarets Forskningsinstitutt FFI | Lindback T.,Norwegian University of Life Sciences
BMC Microbiology | Year: 2014

Background: L-alanine, acting through the GerA receptor, was recently found to be an efficient germinant in Bacillus licheniformis ATCC14580/DSM13. Results: In this study, we show that several of 46 examined B. licheniformis strains germinate remarkably slower than the type strain when exposed to L-alanine. These strains are not necessarily closely related, as determined by MLST (multi-locus sequence typing). Three of the slow-germinating strains were further examined in order to see whether nucleotide substitutions in the gerA sequences were responsible for the slow L-alanine germination. This was performed by complementing the transformable type strain derivate MW3ΔgerAA with gerA variants from the three slow-germinating strains; NVH1032, NVH1112 and NVH800. Conclusions: A wide selection of B. licheniformis strains was evaluated for L-alanine-induced germination efficiency. Our results show that gerA substitutions could only partially explain why spores of some B. licheniformis strains responded slower than others in the presence of L-alanine. © 2014 Madslien et al.; licensee BioMed Central Ltd.


Madslien E.H.,Forsvarets Forskningsinstitutt FFI | Ronning H.T.,Section for Food Safety | Lindback T.,Section for Food Safety | Hassel B.,Forsvarets Forskningsinstitutt FFI | And 2 more authors.
Journal of Applied Microbiology | Year: 2013

Aims: The aim of this study was to elucidate the prevalence of lichenysin production in Bacillus licheniformis and to see whether this feature was restricted to certain genotypes. Secondly, we wanted to see whether cytotoxicity reflected the measured levels of lichenysin. Methods and Results: Fifty-three genotyped strains of B. licheniformis, representing a wide variety of sources, were included. lchAA gene fragments were detected in all strains by polymerase chain reaction (PCR). All 53 strains produced lichenysins with four molecular masses as confirmed by LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis. The amounts of lichenysin varied more than two orders of magnitude between strains and were irrespective of genotype. Finally, there was a strong association between lichenysin concentrations and toxicity towards boar spermatozoa, erythrocytes and Vero cells. Conclusions: Lichenysin synthesis was universal among the 53 B. licheniformis strains examined. The quantities varied considerably between strains, but were not specifically associated with genotype. Cytotoxicity was evident at lichenysin concentrations above 10 μg ml-1, which is in accordance with previous studies. Significance and Impact of Study: This study might be of interest to those working on B. licheniformis for commercial use as well as for authorities who make risk assessments of B. licheniformis when used as a food and feed additive. © 2013 The Society for Applied Microbiology.

Discover hidden collaborations