Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==Enrichment
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Discovering novel hydrolases from hot environments
Wohlgemuth, Roland ; Littlechild, Jennifer ; Monti, Daniela ; Schnorr, Kirk ; Rossum, Teunke van; Siebers, Bettina ; Menzel, Peter ; Kublanov, Ilya V. ; Rike, Anne Gunn ; Skretas, Georgios ; Szabo, Zalan ; Peng, Xu ; Young, Mark J. - \ 2018
Biotechnology Advances 36 (2018)8. - ISSN 0734-9750 - p. 2077 - 2100.
Biocatalysis - Enrichment - Enzyme characterization - Enzyme screening - Gene expression - Genomics - Hydrolases - Metagenomics - Sequencing - Thermophiles

Novel hydrolases from hot and other extreme environments showing appropriate performance and/or novel functionalities and new approaches for their systematic screening are of great interest for developing new processes, for improving safety, health and environment issues. Existing processes could benefit as well from their properties. The workflow, based on the HotZyme project, describes a multitude of technologies and their integration from discovery to application, providing new tools for discovering, identifying and characterizing more novel thermostable hydrolases with desired functions from hot terrestrial and marine environments. To this end, hot springs worldwide were mined, resulting in hundreds of environmental samples and thousands of enrichment cultures growing on polymeric substrates of industrial interest. Using high-throughput sequencing and bioinformatics, 15 hot spring metagenomes, as well as several sequenced isolate genomes and transcriptomes were obtained. To facilitate the discovery of novel hydrolases, the annotation platform Anastasia and a whole-cell bioreporter-based functional screening method were developed. Sequence-based screening and functional screening together resulted in about 100 potentially new hydrolases of which more than a dozen have been characterized comprehensively from a biochemical and structural perspective. The characterized hydrolases include thermostable carboxylesterases, enol lactonases, quorum sensing lactonases, gluconolactonases, epoxide hydrolases, and cellulases. Apart from these novel thermostable hydrolases, the project generated an enormous amount of samples and data, thereby allowing the future discovery of even more novel enzymes.

Indirect Genetic Effects for Growth in Pigs Affect Behaviour and Weight Around Weaning
Camerlink, Irene ; Ursinus, Winanda W. ; Bartels, Andrea C. ; Bijma, Piter ; Bolhuis, J.E. - \ 2018
Behavior Genetics 48 (2018)5. - ISSN 0001-8244 - p. 413 - 420.
Breeding - Enrichment - Genotype-by-environment - Indirect genetic effects - Pig - Weaning

Selection for indirect genetic effects (IGE), i.e. the genetic effect of an individual on a trait of another individual, is a promising avenue to increase trait values in plant and animal breeding. Studies in livestock suggest that selection for IGE for growth (IGEg) might increase animals’ capacity to tolerate stress. We assessed the effect of a stressful phase (weaning) on the behaviour and performance of pigs (n = 480) divergently selected for high or low IGEg. High IGEg pigs were significantly slower to explore the feed and gained less weight than low IGEg pigs in the days after weaning. In line with previous findings, high IGEg animals may have prioritized the formation of social ranks.

Effects of loose housing and the provision of alternative nesting material on peri-partum sow behaviour and piglet survival
Bolhuis, J.E. ; Raats-van den Boogaard, A.M.E. ; Hoofs, A.I.J. ; Soede, N.M. - \ 2018
Applied Animal Behaviour Science 202 (2018). - ISSN 0168-1591 - p. 28 - 33.
Behaviour - Enrichment - Loose housing - Nest-building - Parturition - Sow
Sows are strongly motivated to perform nestbuilding behaviour before parturition. This behaviour is often restricted in commercial systems due to confinement of the sow and lack of suitable nesting material to be used on slatted floors. This study aimed to investigate effects of loose vs. crated housing and the provision of alternative nesting material on periparturient sow behaviour and piglet survival. In a 2 × 2 arrangement, sixty-eight sows were assigned to either loose housing or crates and were either or not provided with nesting material consisting of jute sacks and straw balls. All sows had a rope. Postures and manipulation of materials and pen were observed using 5 min scan sampling for the 12 h before and the 24 h after parturition. Behaviour during parturition was scored continuously and included nose-nose contact between sow and piglets and crushing incidences. No interactions between treatments were found. In the 12 h prepartum, loose housed sows showed less sitting (5 vs. 9%) and ventral lying (29 vs. 38%) and more lateral lying (33 vs. 23%) and floor manipulation (10 vs. 5%) than crated sows. During parturition, loose housed sows spent less time sitting (2 vs. 6%), had fewer postural changes (34 vs. 50), showed less fence manipulation (0.1 vs. 2%) and had more nose contact with piglets (56 vs. 19 times). Provision of nesting material increased pre-partum lying (63 vs. 57%), increased manipulation of materials (14 vs. 8%) and reduced manipulation of floor (5 vs. 10%) and fence (5 vs. 9%). During parturition, sows with nesting material showed less standing (6 vs. 10%) and more lying (90 vs. 84%). No effects were found on behaviour in the 24 h after parturition or on parturition duration (3.3 ± 0.1 h). During parturition, the times lying down and the number of piglets that died by crushing tended to be lower with provision of nesting material (0.1 vs. 0.3). In the 48 h after parturition, loose housed sows crushed more piglets. In conclusion, both loose housing and the provision of alternative nesting materials affected prepartum sow behaviour and resulted in less activity during parturition, with some tendencies for beneficial effects on (near-) crushing of piglets during this period. Thus, both loose housing and the provision of alternative nesting materials, likely particularly the jute sacks, have a beneficial effect on periparturient sow behaviour.
Evidence-Based Reptile Housing and Nutrition
Oonincx, Dennis ; Leeuwen, Jeroen van - \ 2017
Veterinary Clinics of North America - Exotic Animal Practice 20 (2017)3. - ISSN 1094-9194 - p. 885 - 898.
Enrichment - Nutrition - Reptiles - Ultraviolet light - Vitamin D - Welfare - 017-4031
The provision of a good light source is important for reptiles. For instance, ultraviolet light is used in social interactions and used for vitamin D synthesis. With respect to housing, most reptilians are best kept pairwise or individually. Environmental enrichment can be effective but depends on the form and the species to which it is applied. Temperature gradients around preferred body temperatures allow accurate thermoregulation, which is essential for reptiles. Natural distributions indicate suitable ambient temperatures, but microclimatic conditions are at least as important. Because the nutrient requirements of reptiles are largely unknown, facilitating self-selection from various dietary items is preferable.
Determination of single cell lag times of Cronobacter spp. strains exposed to different stress conditions : Impact on detection
Margot, H. ; Zwietering, M.H. ; Joosten, H. ; Stephan, R. - \ 2016
International Journal of Food Microbiology 236 (2016). - ISSN 0168-1605 - p. 161 - 166.
Bacterial inactivation - Enrichment - Powdered infant formula - Sampling plan - Simulation - Strain variability

The variability of stress resistance and lag time of single cells can have a big impact on their growth and therefore on the probability of their detection in food. In this study, six strains of Cronobacter spp. were subjected to heat, acid and desiccation stress and single cell lag times were determined using optical density measurements. The duration of lag time was highest after acid stress and did not correlate to stress resistance. The effect that the inactivation caused by stress and an extended lag time had on the projected cfu level reached after enrichment was simulated in different scenarios. For most strains, an enrichment time of 18 h was sufficient for stressed cells to reach the suggested minimum level of cell inoculum for the Cronobacter screening broth detection. Particular strains may require longer recovery periods. Further, probability calculations showed that the number of samples taken from a batch may have an important effect on detection probability, especially at low contamination rates. Therefore, in addition to increasing the recovery period, increasing the number of samples is a suitable strategy to improve detection.

A novel consortium of Lactobacillus rhamnosus and Streptococcus thermophilus for increased access to functional fermented foods
Kort, Remco ; Westerik, Nieke ; Mariela Serrano, L. ; Douillard, François P. ; Gottstein, Willi ; Mukisa, Ivan M. ; Tuijn, Coosje J. ; Basten, Lisa ; Hafkamp, Bert ; Meijer, Wilco C. ; Teusink, Bas ; Vos, Willem de; Reid, Gregor ; Sybesma, Wilbert - \ 2015
Microbial Cell Factories 14 (2015)1. - ISSN 1475-2859
Bacterial fermentation - Consortium - Enrichment - Fermented foods - Functional foods - Lactobacillus rhamnosus GG - Lactobacillus rhamnosus yoba 2012 - Streptococcus thermophilus C106 - Yoghurt

Background: The lactic acid bacterium Lactobacillus rhamnosus GG is the most studied probiotic bacterium with proven health benefits upon oral intake, including the alleviation of diarrhea. The mission of the Yoba for Life foundation is to provide impoverished communities in Africa increased access to Lactobacillus rhamnosus GG under the name Lactobacillus rhamnosus yoba 2012, world's first generic probiotic strain. We have been able to overcome the strain's limitations to grow in food matrices like milk, by formulating a dried starter consortium with Streptococcus thermophilus that enables the propagation of both strains in milk and other food matrices. The affordable seed culture is used by people in resource-poor communities. Results: We used S. thermophilus C106 as an adjuvant culture for the propagation of L. rhamnosus yoba 2012 in a variety of fermented foods up to concentrations, because of its endogenous proteolytic activity, ability to degrade lactose and other synergistic effects. Subsequently, L. rhamnosus could reach final titers of 1E+09CFUml-1, which is sufficient to comply with the recommended daily dose for probiotics. The specific metabolic interactions between the two strains were derived from the full genome sequences of L. rhamnosus GG and S. thermophilus C106. The piliation of the L. rhamnosus yoba 2012, required for epithelial adhesion and inflammatory signaling in the human host, was stable during growth in milk for two rounds of fermentation. Sachets prepared with the two strains, yoba 2012 and C106, retained viability for at least 2 years. Conclusions: A stable dried seed culture has been developed which facilitates local and low-cost production of a wide range of fermented foods that subsequently act as delivery vehicles for beneficial bacteria to communities in east Africa.

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