Zebrafish (Danio rerio) as an animal model for bath infection by Flavobacterium psychrophilum.

Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout syndrome in freshwater salmonid fish worldwide, generating injuries and high mortality rates. Despite several studies on this bacterium, the infection mechanism remains unknown due to limitations in the employed animal models. In this work, we propose using zebrafish (Danio rerio) as a model for studying bacterial pathogenicity.

Wnt/β-catenin signaling stimulates the expression and synaptic clustering of the autism-associated Neuroligin 3 gene.

Synaptic abnormalities have been described in individuals with autism spectrum disorders (ASD). The cell-adhesion molecule Neuroligin-3 (Nlgn3) has an essential role in the function and maturation of synapses and NLGN3 ASD-associated mutations disrupt hippocampal and cortical function. Here we show that Wnt/β-catenin signaling increases Nlgn3 mRNA and protein levels in HT22 mouse hippocampal cells and primary cultures of rat hippocampal neurons.

Cytotoxic activity of Flavobacterium psychrophilum in skeletal muscle cells of rainbow trout (Oncorhynchus mykiss).

Flavobacterium psychrophilum is the etiologic agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), which cause significant worldwide losses in aquaculture. Juvenile rainbow trout are particularly susceptible to F. psychrophilum infection, the main external clinical signs of which are extensive necrotic myositis and ulcerative lesions.

Cxcl8b and Cxcr2 Regulate Neutrophil Migration through Bloodstream in Zebrafish.

Neutrophils play an essential role during an inflammatory response, which is dependent on their rapid recruitment from the bone marrow to the vasculature. However, there is no information about the molecular signals that regulate neutrophil entry to circulation during an inflammatory process in humans. This is mainly due to the lack of a suitable model of study that contains similar set of molecules and that allows in vivo analyses.

Neutrophil migration in the activation of the innate immune response to different Flavobacterium psychrophilum vaccines in zebrafish (Danio rerio).

Flavobacterium psychrophilum is a Gram-negative bacterium, responsible for the bacterial cold-water disease and the rainbow trout fry syndrome in freshwater salmonid fish. At present, there is only one commercial vaccine in Chile, made with two Chilean F. psychrophilum isolates and another licensed in Europe.

Gcsf-Chr19 promotes neutrophil migration to damaged tissue through blood vessels in zebrafish.

G-CSF is an essential cytokine that regulates proliferation and differentiation of granulocytes from hematopoietic stem and progenitor cells. In mammals G-CSF has been identified as a key factor that promotes the release of neutrophils from the bone marrow into the blood circulation. In silico analysis indicates that zebrafish has two gcsf genes, gcsf-chr12 in chromosome 12 and gcsf-chr19 in chromosome 19.

Overrepresentation of glutamate signaling in Alzheimer's disease: network-based pathway enrichment using meta-analysis of genome-wide association studies.

Genome-wide association studies (GWAS) have successfully identified several risk loci for Alzheimer's disease (AD). Nonetheless, these loci do not explain the entire susceptibility of the disease, suggesting that other genetic contributions remain to be identified. Here, we performed a meta-analysis combining data of 4,569 individuals (2,540 cases and 2,029 healthy controls) derived from three publicly available GWAS in AD and replicated a broad genomic region (>248,000 bp) associated with the disease near the APOE/TOMM40 locus in chromosome 19.

Soybean meal induces intestinal inflammation in zebrafish larvae.

The necessary replacement of fish meal with other protein source in diets of commercially important fish has prompted the study of the effect of the inclusion of different vegetable proteins sources on growth performance and on the gastro-intestinal tract. Currently, soybean meal is the primary protein source as a fish meal replacement because of its low price and high availability. Likewise, it is been documented that the ingestion of soybean meal by several fish species, such as salmonids and carp, triggers a type of intestinal inflammation called enteritis.

The hypoxia factor Hif-1α controls neural crest chemotaxis and epithelial to mesenchymal transition.

One of the most important mechanisms that promotes metastasis is the stabilization of Hif-1 (hypoxia-inducible transcription factor 1). We decided to test whether Hif-1α also was required for early embryonic development. We focused our attention on the development of the neural crest, a highly migratory embryonic cell population whose behavior has been likened to cancer metastasis.

A novel functional low-density lipoprotein receptor-related protein 6 gene alternative splice variant is associated with Alzheimer's disease.

We previously found that single nucleotide polymorphisms in the low-density lipoprotein receptor-related protein 6 (LRP6) gene are associated with Alzheimer's disease (AD). Here, we studied the posttranscriptional metabolism of the LRP6 message scanning sequentially the 23 LRP6 exons in human tissues and found a novel LRP6 isoform that completely skips exon 3 (LRP6Δ3) in all tissues examined and was also conserved in mice. Expression levels of the LRP6 isoforms were determined in 47 cortical brain messenger (m)RNA samples including 22 AD cases, 11 control subjects, and 14 individuals with other neurological disorders.

Sublethal concentrations of waterborne copper induce cellular stress and cell death in zebrafish embryos and larvae.

Copper is an essential ion that forms part of the active sites of many proteins. At the same time, an excess of this metal produces free radicals that are toxic for cells and organisms. Fish have been used extensively to study the effects of metals, including copper, present in food or the environment.

Molecular cloning of IGF-1 and IGF-1 receptor and their expression pattern in the Chilean flounder (Paralichthys adspersus).

Insulin-like growth factor-1 and insulin-like growth factor-1 receptor (IGF-1 and IGF-1R) play main roles in vertebrate growth and development. In fish, besides contributing to somatic growth, both molecules exhibit pleiotropic functions. We isolated complete cDNAs sequences encoding for both IGF-1 and IGF-1R in the Chilean flounder by using RT-PCR and rapid amplification of cDNAs ends (RACE) techniques.

Evolution of the interaction between Runx2 and VDR, two transcription factors involved in osteoblastogenesis.

Background: The mineralized skeleton is a major evolutionary novelty that has contributed to the impressive morphological diversifications of the vertebrates. Essential to bone biology is the solidified extracellular matrix secreted by highly specialized cells, the osteoblasts. We now have a rather complete view of the events underlying osteogenesis, from a cellular, molecular, genetic, and epigenetic perspective.

Growth hormone receptors in zebrafish (Danio rerio): adult and embryonic expression patterns.

Growth hormone receptor (GHR) is a critical regulator of growth and metabolism. Although two GHRs have been characterized in many fish species, their functional characteristics, mechanisms of regulation and roles in embryonic development remain unclear. The zebrafish (Danio rerio) is an excellent model organism to study both developmental and physiological processes.

Temporal and spatial expression pattern of the myostatin gene during larval and juvenile stages of the Chilean flounder (Paralichthys adspersus).

The full length cDNA sequence of the myostatin gene was cloned from a teleostean fish, the Chilean flounder (Paralichthys adspersus) through RT-PCR amplification coupled with the RACE approach to complete the 5'- and 3'-region. The deduced amino acid sequence encodes a protein of 377 amino acid residues, including the structural domains responsible for its biological activity. Amino acid sequence comparison revealed high sequence conservation, and confirmed that the isolated sequence corresponds to the MSTN1 gene.

Dynamic expression pattern of the growth hormone receptor during early development of the Chilean flounder.

The entire cDNA sequence of the growth hormone receptor (GHR) of the Chilean flounder (Paralichthys. adspersus) was cloned by RT-PCR and RNA ligase rapid amplification of 5' and 3'ends. The deduced amino acid sequence contains 641 residues and codes for the GHR1 form.

The CK1 gene family: expression patterning in zebrafish development.

Protein kinase CK1 is a ser/thr protein kinase family which has been identified in the cytosol cell fraction, associated with membranes as well as in the nucleus. Several isoforms of this gene family have been described in various organisms: CK1alpha, CK1beta, CK1delta, CK1epsilon and CK1gamma. Over the last decade, several members of this family have been involved in development processes related to wnt and sonic hedgehog signalling pathways.

Snail1a and Snail1b cooperate in the anterior migration of the axial mesendoderm in the zebrafish embryo.

The Snail genes are implicated in processes that involve cell movement, both during embryonic development and tumour progression. In teleosts, the vertebrate Snail1 gene is represented by two distinct genes, snail1a and snail1b (previously snail1 and snail2). These genes are expressed in complementary mesodermal domains and their combined expression matches that of their mammalian counterpart.

Gene structure and seasonal expression of carp fish prolactin short receptor isoforms.

The complex adaptive mechanisms that eurythermal fish have evolved in response to the seasonal changes of the environment include the transduction of the physical parameter variations into neuroendocrine signals. Studies in carp (Cyprinus carpio) have indicated that prolactin (PRL) and growth hormone (GH) expression is associated with acclimatization, suggesting that the pituitary gland is a relevant physiological node in this adaptive process. Also, the distinctive pattern of expression that carp prolactin receptor (PRLr) protein depicts upon seasonal acclimatization supports the hypothesis that PRL and its receptor clearly are involved in the new homeostatic stage that the eurythermal fish needs to survive during the cyclical changes of its habitat.

Cloning of hif-1alpha and hif-2alpha and mRNA expression pattern during development in zebrafish.

Hypoxia-inducible factors (HIFs) regulate gene expression in response to hypoxia and in vertebrates they are known to participate in several developmental processes, including angiogenesis, vasculogenesis, heart and central nervous system development. Over the last decade, major progress in unraveling the molecular mechanisms that mediate regulation of HIF proteins by oxygen tension has been reported, but our knowledge on their developmental regulation during embryogenesis in model organisms is limited. Expression of hif-1alpha and hif-2alpha genes has been characterized during normal mouse development and they were found to be expressed from stages E7.

Is there a role for copper in neurodegenerative diseases?

Copper is an essential metal in living organisms; thus, the maintenance of adequate copper levels is of vital importance and is highly regulated. Dysfunction of copper metabolism leading to its excess or deficiency results in severe ailments. Two examples of illnesses related to alterations in copper metabolism are Menkes and Wilson diseases.

Human-like rodent amyloid-beta-peptide determines Alzheimer pathology in aged wild-type Octodon degu.

It is generally accepted that human Alzheimer's disease (AD) neuropathology markers are completely absent in rodent brains. We report here that an aged wild-type South American rodent, Octodon degu, expresses neuronal beta-amyloid precursor protein (beta-APP695) displaying both intracellular and extracellular deposits of amyloid-beta-peptide (Abeta), intracellular accumulations of tau-protein and ubiquitin, a strong astrocytic response and acetylcholinesterase (AChE)-rich pyramidal neurons. The high amino acid homology (97.

Acetylcholinesterase-Abeta complexes are more toxic than Abeta fibrils in rat hippocampus: effect on rat beta-amyloid aggregation, laminin expression, reactive astrocytosis, and neuronal cell loss.

Neuropathological changes generated by human amyloid-beta peptide (Abeta) fibrils and Abeta-acetylcholinesterase (Abeta-AChE) complexes were compared in rat hippocampus in vivo. Results showed that Abeta-AChE complexes trigger a more dramatic response in situ than Abeta fibrils alone as characterized by the following features observed 8 weeks after treatment: 1). amyloid deposits were larger than those produced in the absence of AChE.

Cloning, expression pattern and essentiality of the high-affinity copper transporter 1 (ctr1) gene in zebrafish.

The high-affinity copper transporter 1 (Ctr1) is a highly conserved transmembrane protein that mediates the internalization of copper ions from the extracellular medium. In this study, we have isolated the zebrafish ctr1 gene. The zebrafish ctr1 cDNA encodes a protein with 69% identity to the human orthologue and shows conservation of specific amino acid residues involved in copper transport.

Acetylcholinesterase induces neuronal cell loss, astrocyte hypertrophy and behavioral deficits in mammalian hippocampus.

Previous studies have demonstrated that acetylcholinesterase (AChE) promotes the assembly of amyloid-beta-peptides into neurotoxic amyloid fibrils and is toxic for chick retina neuronal cultures and neuroblastoma cells. Moreover, AChE is present in senile plaques in Alzheimer's disease (AD) brains. Here we have studied the effect of AChE on astrocytes and hippocampal neurons in vivo.