Strategies for estimating human exposure to mycotoxins via food
Nijs, M. De; Mengelers, M.J.B. ; Boon, P.E. ; Heyndrickx, E. ; Hoogenboom, L.A.P. ; Lopez, P. ; Mol, H.G.J. - \ 2016
World Mycotoxin Journal 9 (2016)5. - ISSN 1875-0710 - p. 831 - 845.
Duplicate diet study - Exposure assessment - Food consumption - Food monitoring - Human biomonitoring - Mycotoxins - Total diet study
In this review, five strategies to estimate mycotoxin exposure of a (sub-)population via food, including data collection, are discussed with the aim to identify the added values and limitations of each strategy for risk assessment of these chemicals. The well-established point estimate, observed individual mean, probabilistic and duplicate diet strategies are addressed, as well as the emerging human biomonitoring strategy. All five exposure assessment strategies allow the estimation of chronic (long-Term) exposure to mycotoxins, and, with the exception of the observed individual mean strategy, also acute (short-Term) exposure. Methods for data collection, i.e. food consumption surveys, food monitoring studies and total diet studies are discussed. In food monitoring studies, the driving force is often enforcement of legal limits, and, consequently, data are often generated with relatively high limits of quantification and targeted at products suspected to contain mycotoxin levels above these legal limits. Total diet studies provide a solid base for chronic exposure assessments since they provide mycotoxin levels in food based on well-defined samples and including the effect of food preparation. Duplicate diet studies and human biomonitoring studies reveal the actual exposure but often involve a restricted group of human volunteers and a limited time period. Human biomonitoring studies may also include exposure to mycotoxins from other sources than food, and exposure to modified mycotoxins that may not be detected with current analytical methods. Low limits of quantification are required for analytical methods applied for data collection to avoid large uncertainties in the exposure due to high numbers of left censored data, i.e. with levels below the limit of quantification.
Construction and validation of a mCherry protein vector for promoter analysis in Lactobacillus acidophilus
Mohedano, M.L. ; Garcia-Cayuela, T. ; Perez-Ramos, A. ; Gaiser, R.A. ; Requena, T. ; Lopez, P. - \ 2015
Journal of Industrial Microbiology and Biotechnology 42 (2015)2. - ISSN 1367-5435 - p. 247 - 253.
lactic-acid bacteria - controlled gene-expression - streptococcus-pneumoniae - lactococcus-lactis - plasmid - cloning
Lactobacilli are widespread in natural environments and are increasingly being investigated as potential health modulators. In this study, we have adapted the broad-host-range vector pNZ8048 to express the mCherry protein (pRCR) to expand the usage of the mCherry protein for analysis of gene expression in Lactobacillus. This vector is also able to replicate in Streptococcus pneumoniae and Escherichia coli. The usage of pRCR as a promoter probe was validated in Lactobacillus acidophilus by characterizing the regulation of lactacin B expression. The results show that the regulation is exerted at the transcriptional level, with lbaB gene expression being specifically induced by co-culture of the L. acidophilus bacteriocin producer and the S. thermophilus STY-31 inducer bacterium.
Is the reaction to chemical cues of predators affected by age or experience in fire salamanders (Salamandra salamandra)
Ibanez, A. ; Caspers, B.A. ; Lopez, P. ; Martin, J. ; Krause, E.T. - \ 2014
Amphibia-Reptilia 35 (2014)2. - ISSN 0173-5373 - p. 189 - 196.
diet cues - recognition - avoidance - risk - population - prospectus - preference - responses - tadpoles - behavior
Predation is one of the strongest forces driving natural selection. Predator success reduces future prey fitness to zero. Thus, recognition and avoidance of a potential predator is an essential fitness-relevant skill for prey. Being well equipped in the predator-prey arms race is highly adaptive. In this context we tested whether age and/or potential experience of fire salamanders (Salamandra salamandra) affected their behaviour towards the chemical signature of a potential predator. We evaluated the space use of salamanders in a test arena with a shelter containing chemical cues from a predator (i.e., a rat) and a clean shelter. Our results demonstrate that naïve subadult fire salamanders do show a significant behavioural reaction towards rat odour. However, they do not avoid the chemical cues of the potential predator, but instead have a significant preference for the shelter with rat faeces. In contrast to this, both the naïve adult and wild-caught adult fire salamanders showed neither a preference nor an avoidance of rat scent. These results could suggest a role of age in odour-based predator recognition in salamanders. Similarly, predator recognition through chemical cues could be more important early in life when the young fire salamanders are more vulnerable to predatory attacks and less important in other life stages when salamanders are less subjected to predation. In conclusion, future studies considering wild-caught subadults should disentangle the importance of previous experience for predator chemical recognition.