Publications by authors named "Michael E Nielsen"

Infection with is a critical cause of gastrointestinal diseases. A crucial host response associated with infection includes gastric inflammation, which is characterized by a sustained recruitment of T-helper (Th) cells to the site of infection and distinct patterns of cytokine production. Adequate nutritional status, especially frequent consumption of dietary antioxidants, appears to protect against infection with .

View Article and Find Full Text PDF

Astaxanthin, a xanthophyll carotenoid, is a secondary metabolite naturally synthesized by a number of bacteria, microalgae, and yeasts. The commercial production of this pigment has traditionally been performed by chemical synthesis, but the microalga appears to be the most promising source for its industrial biological production. Due to its collective diverse functions in skin biology, there is mounting evidence that astaxanthin possesses various health benefits and important nutraceutical applications in the field of dermatology.

View Article and Find Full Text PDF

We investigated the effect of full-thickness incisional wounding on expression of genes related to the immune system in larvae and juveniles of common carp (Cyprinus carpio). The wounds were inflicted by needle puncture immediately below the anterior part of the dorsal fin on days 7, 14, 28 and 49 after fertilization. We followed the local gene expression 1, 3 and 7 days after wounding by removing head and viscera before extracting RNA from the remaining part of the fish, including the wound area.

View Article and Find Full Text PDF

Authentication of food is a major concern worldwide to ensure that food products are correctly labeled in terms of which animals are actually processed for consumption. Normally authentication is based on species recognition by comparison of selected sequences of DNA or protein. We here present a new robust, proteome-wide tandem mass spectrometry method for species recognition and food product authentication.

View Article and Find Full Text PDF

The aim of this study was to investigate the possibility of predicting the type and concentration level of astaxanthin coating of aquaculture feed pellets using multispectral image analysis. We used both natural and synthetic astaxanthin, and we used several different concentration levels of synthetic astaxanthin in combination with four different recipes of feed pellets. We used a VideometerLab with 20 spectral bands in the range of 385-1050 nm.

View Article and Find Full Text PDF

The response to tissue damage is a complex process, which involves the coordinated regulation of multiple proteins to ensure tissue repair. In order to investigate the effect of tissue damage in a lower vertebrate, samples were taken from rainbow trout (Oncorhynchus mykiss) at day 7 after damage and proteins were separated using 2DE. The experimental design included two groups of rainbow trout, which were fed organic feed either with or without astaxanthin.

View Article and Find Full Text PDF

When producing aquaculture fish feed pellets, the size of the output product is of immense importance. As the production method cannot produce pellets of constant and uniform size using constant machine settings, there is a demand for size control. Fish fed with feed pellets of improper size are prone to not grow as expected, which is undesirable to the aquaculture industry.

View Article and Find Full Text PDF

Multispectral imaging has been evaluated for characterization of the concentration of a specific cartenoid pigment; astaxanthin. 59 fillets of rainbow trout, Oncorhynchus mykiss, were filleted and imaged using a rapid multispectral imaging device for quantitative analysis. The multispectral imaging device captures reflection properties in 19 distinct wavelength bands, prior to determination of the true concentration of astaxanthin.

View Article and Find Full Text PDF

Fibroblasts have shown to be an immune competent cell type in mammals. However, little is known about the immunological functions of this cell-type in lower vertebrates. A rainbow trout hypodermal fibroblast cell-line (RTHDF) was shown to be responsive to PAMPs and DAMPs after stimulation with LPS from E.

View Article and Find Full Text PDF

A real-time PCR assay for determination of the complement response to infection with the ectoparasite Ichthyophthirius multifiliis in carp is presented. Specific primers were designed for selected genes representing the three pathways of the carp complement system. The investigated complement molecules were C1r/s, C3, C4, C5, factor I, factor B/C2-A (Bf/C2-A), mannose-binding lectin (MBL) and MBL-associated serine protease (MASP).

View Article and Find Full Text PDF

A real time quantitative PCR (RQ-PCR) assay was developed for measurement of differential expression of the genes encoding the acute phase reactant serum amyloid A (SAA), transferrin (TF) and a C-type lectin molecule (CL) in skin, blood and liver from Cyprinus carpio following infection with the ectoparasite Ichthyophthirius multifiliis. Serum amyloid A and CL were constitutively expressed in all organs evaluated while TF transcripts were only detected in the liver. A dramatic up-regulation (1600 times) in the expression levels of SAA was observed in skin 36 h after the parasite infection.

View Article and Find Full Text PDF

In order to detect new immune-related genes in common carp (Cyprinus carpio L.) challenged by an ectoparasitic infection, two cDNA libraries were constructed from carp skin sampled at 3 and 72h after infection with Ichthyophthirius multifiliis. In a total of 3500 expressed sequence tags (ESTs) we identified 82 orthologues of genes of immune relevance previously described in other organisms.

View Article and Find Full Text PDF

Real time quantitative PCR (RQ-PCR) assays were developed for the measurement of differential real-time expression of immune-related genes in skin and whole blood from Cyprinus carpio during an infection with the ectoparasite Ichthyophthirius multifiliis. The target genes included the chemokines CXCa and CXCb, the chemokine receptors CXCR1 and CXCR2, the pro-inflammatory cytokines interleukin 1 beta (IL-1beta) and tumour necrosis factor alpha (TNF-alpha) and the enzymes inducible nitric oxide synthase (iNOS) and arginase 2. The strongest up-regulation in skin was observed in the IL-1beta, CXCR1 and iNOS genes at 36-48h post-exposure to theronts.

View Article and Find Full Text PDF

We studied a predictive model of gene expression induced by mechanical injury of fish skin, to resolve the confounding effects on the immune system induced by injury and skin parasite-specific molecules. We applied real time quantitative PCR (RQ-PCR) to measure the expression of the pro-inflammatory cytokines CXCa, CXCb, interleukin (IL)1-beta, tumor necrosis factor alpha (TNFalpha), and the receptors IL1R1, CXCR1 and CXCR2 in skin of Cyprinus carpio after mechanical injury. We also studied the expression of the anti-inflammatory cytokine IL-10.

View Article and Find Full Text PDF

We coupled multiplex PCR and a DNA microarray to construct an assay suitable for the simultaneous detection of five important marine fish pathogens (Vibrio vulnificus, Listonella anguillarum, Photobacterium damselae subsp. damselae, Aeromonas salmonicida subsp. salmonicida, and Vibrio parahaemolyticus).

View Article and Find Full Text PDF

Two decades of research have established the zebrafish (Danio rerio) as a significant model system for studying vertebrate development and gene structure-function relationships. Recent advances in mutation screening, the creation of genomic resources, including the Zebrafish Genome Project and the development of efficient transgenesis procedures, make this model increasingly attractive for immunological study.

View Article and Find Full Text PDF