Carmen G Feijoo

Universidad Andrés Bello | UNAB · Department of Biology

Intestinal macrophages have been poorly studied in fish, mainly due to the lack of specific molecular markers for their identification and isolation. To address this gap, using the zebrafish Tg(mpeg1:EGFP) transgenic line, we developed a fluorescence-activated cell sorting strategy (FACS) that allows us to isolate different intestinal macrophage su...

Vibrio anguillarum is a pathogen for several fish and shellfish species. Its ecology is influenced by diverse factors, including bacteriophages. Here, we identify and characterize a new temperate bacteriophage (Valp1) of V. anguillarum. Valp1 is a myovirus with a 60 nm head and a 90 nm contractile tail. Its double-stranded DNA genome of 42,988 bp c...

In all organisms studied, from flies to humans, blood cells emerge in several sequential waves and from distinct hematopoietic origins. However, the relative contribution of these ontogenetically distinct hematopoietic waves to embryonic blood lineages and to tissue regeneration during development is yet elusive. Here, using a lineage-specific “swi...

The current view of hematopoiesis considers leukocytes on a continuum with distinct developmental origins, and which exert non-overlapping functions. However, there is less known about the function and phenotype of ontogenetically distinct neutrophil populations. In this work, using a photoconvertible transgenic zebrafish line; Tg(mpx:Dendra2), we...

Sepsis syndrome develops through enhanced secretion of pro-inflammatory cytokines and the generation of reactive oxygen species (ROS). Sepsis syndrome is characterized by vascular hyperpermeability, hypotension, multiple organ dysfunction syndrome (MODS), and increased mortality, among others. Endotoxemia-derived sepsis is an important cause of sep...

Background Sepsis is an uncontrolled inflammatory response against a systemic infection that results in elevated mortality, mainly induced by bacterial products known as endotoxins, producing endotoxemia. Disseminated intravascular coagulation (DIC) is frequently observed in septic patients and is associated with organ failure and death. Sepsis act...

Sepsis syndrome is a highly lethal uncontrolled response to an infection, which is characterized by sepsis-induced coagulopathy (SIC). High-density lipoprotein (HDL) exhibits antithrombotic activity, regulating coagulation in vascular endothelial cells. Sepsis induces the release of several proinflammatory molecules, including reactive oxygen speci...

Plant-based protein sources, such as soybean, are widely used in fish nutrition due to their market availability, wide distribution and acceptable nutritional quality. However, in some fish species, soybean meal-based diets cause gut inflammation, decreasing both nutrient absorption and growth rates. A suitable alternative to avoid these problems c...

Organized intestinal mucosal immune response appears to be restricted to tetrapods. In teleost fish, there is no evidence for the existence of a particular intestinal region that facilitates the interaction of antigen-presenting cells (APCs) and T cells, such as secondary lymphoid organs. Indeed, despite their importance in the defense against path...

Little is known about the diversity in immune profile of the different wild type strains of zebrafish (Danio rerio), despite its growing popularity as an animal model to study human diseases and drug testing. In the case of data resulting from modeling human diseases, differences in the background Danio fishes have rarely been taken into considerat...

The host microbiome plays an essential role in health and disease. Microbiome modification by pathogens or probiotics has been poorly explored especially in the case of probiotic yeasts. Next-generation sequencing currently provides the best tools for their characterization. Debaryomyces hansenii 97 (D. hansenii 97) and Yarrowia lipolytica 242 (Y....

One of main drawbacks for the treatment of neurodegenerative pathologies is ensuring the delivery of therapeutic agents into the central nervous system (CNS). Nowadays, gold nanoprisms (GNPr) have become an emerging nanomaterial with a localized surface plasmon resonance in the biological window, showing applications in both detection and treatment...

Anesthetic failure is common in dental inflammation processes, even when modern agents, such as articaine, are used. Nanostructured lipid carriers (NLC) are systems with the potential to improve anesthetic efficacy, in which active excipients can provide desirable properties, such as anti-inflammatory. Coupling factorial design (FD) for in vitro fo...

Intestinal inflammation is a condition shared by several intestinal chronic diseases, such as Crohn's disease and ulcerative colitis, with severely detrimental consequences in the long run. Current mammalian models have considerably increased understanding of this pathological condition, highlighting the fact that, in most of the cases, it is a hig...

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 prop...

Gastrointestinal Immunity and Crosstalk with Internal Organs in Fish

Neutrophils are crucial modulators of the inflammation process, and their uncontrolled response worsens several chronic pathologies. The p38 mitogen-activated protein kinases (MAPKs) activity is critical for normal immune and inflammatory response through the regulation of pro-inflammatory cytokines synthesis. In this work, we study the effect of h...

Relative transcriptional level of mhc1zea, mhc2ab, hamp, leap2, trim33, and il23 genes were analyzed in wild type and rag1−/− larvae after performed the naïve model. Data was normalized against rpl13a and compared to the control condition. For each condition, 100 guts were analyzed, and three biological replicates was made. **p < 0.01; ***p < 0.001...

(A) Experimental strategy for naïve and developed feeding model. In the case of the naïve feeding model, 5 dpf larvae were fed with control diet (fishmeal-based diet) or inflammatory diet (soybean meal-based diet) during 4 days until 9 dpf. Samples were collected before and after feeding and behavior of neutrophils, macrophages, mast cells, and lym...

Time lapse showing lck+ cells, lymphocytes, in the intestine of a Tg(lck:lck-eGFP) larva fed the control diet in the naïve model.

Time lapse showing lck+ cells, lymphocytes, in the intestine of a Tg(lck:lck-eGFP) larva fed the inflammatory diet in the naïve model.

Currently, inflammatory bowel disease (IBD) is a serious public health problem on the rise worldwide. In this work, we utilized the zebrafish to introduce a new model of intestinal inflammation triggered by food intake. Taking advantage of the translucency of the larvae and the availability of transgenic zebrafish lines with fluorescently labeled m...

Yeasts are part of the microbiota of healthy fish gut. We previously identified different yeast species from the gut of wild and reared fish, like Cillus gilberti, Seriola lalandi, and salmonids like Salmo salar, Oncorhynchus kisutch and O. mykiss. Some yeasts strains showed protective effects against Vibrio anguillarum in zebrafish larvae, modulat...

DTAF-labeled C. diffilice located in the gastrointestinal tract of larvae.

In this study we evaluated if zebrafish larvae can be colonized by human gut microorganisms. We tested two strategies: (1) through transplantation of a human fecal microbiota and (2) by successively transplanting aerotolerant anaerobic microorganisms, similar to the colonization in the human intestine during early life. We used conventionally raise...

Soybean meal has been used in many commercial diets for farm fish; despite this component inducing intestinal inflammation. On the other hand, microalgae have increasingly been used as dietary supplements in fish feed. Nevertheless, the vast quantity of microalgae species means that many remain under- or unstudied, thus limiting wide scale commerci...

Effect of microalgae on immune response. (A-G) Lateral view of 9 dpf Tg(BACmpo:GFP)i114 larvae after four days of feeding with the different diets; fishmeal (100FM), soybean meal (50SBM), and fishmeal + microalgae: 100FM+Ch, 100FM+Ts, 100FM+A3Ng, 100FM+Pt, or 100FM+No. Black arrowheads indicate neutrophils. (H) The amount of intestinal neutrophils...

Intestinal localization of Edwardsiella tarda after challenge assay. (A, D). Lateral view of a mid-intestine section from a 12dpf larva. (B, E) mCherry labeled Edwardsiella tarda. (C, F) Merge of both images showing the presence or not of Edwardsiella tarda in the intestine. (TIF)

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 ulc...

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 m...

The information of supplementary materials are as follows: Supplementary Figure 1: Morphant phenotype. (A, B, C) Representative images of the different phenotypes observed after Cxcl8a or Cxl8b morpholino microinjection. (A) Control phenotype showing vasculature disruption. (B) Morphant phenotype used in the damage assays, showing 2-3 disruptions o...

We investigated mechanisms involved in the protection of zebrafish (Danio rerio) larvae by two probiotic candidate yeasts, Debaryomyces hansenii 97 (Dh97) and Yarrowia lypolitica 242 (Yl242), against a Vibrio anguillarum challenge. We determined the effect of different yeast concentrations (104–107 CFU/mL) to: (i) protect larvae from the challenge,...

Due to the negative consequences associated with the use of antibiotics, resear- chers and food producers have studied alternatives, such as probiotics, for the control of fish diseases. The probiotic properties of yeasts in aquaculture have been scarcely considered, although they contain various immune-stimulating compounds, which can protect fish...

Intestinal inflammation is a harmful condition in fish that can be triggered by the ingestion of soybean meal. Due to the positive costs-benefits ratio of including soybean meal in farmed fish diets, identifying additives with intestinal anti-inflammatory effects could contribute to solving the issues caused by this plant protein. This study evalua...

The supplementary Figure 1 shows the Sudan Black B staining in order to label leukocytes in the intestine of 9dpf larvae fed with the different diets. Total concordance between these result and those obtained from the immunohistochemistry analysis were found.

Due to the negative consequences associated with the use of antibiotics, researchers, and food producers have studied alternatives, such as probiotics, for the control of fish diseases. The probiotic properties of yeasts in aquaculture have been scarcely considered. The present study investigated the probiotic properties of local yeast strains for...

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. The present study analyzed neutrophil m...

Supplementary Figure 1: Effect on the innate immune response triggered by control medium. Plot of quantified neutrophil migration to the ROI. Statistical analysis was performed by two-way ANOVA. Data represent the mean ± standard error from three independent experiments with 15 larvae each. ∗∗∗∗P-value <0.0001.

The welfare of living creatures is a major issue for science. Thus, health and immune response are fields of intensive research and constant progress. In the past 10 years, the zebrafish (Danio rerio) has gained strength as a model for immunology research. The existence of several transgenic lines with specific cell type fluorescently labeled, allo...

The aquaculture industry continues to promote the diversification of ingredients used in aquafeed in order to achieve a more sustainable aquaculture production system. The evaluation of large numbers of diets in aquaculture species is costly and requires time-consuming trials in some species. In contrast, zebrafish (Danio rerio) can solve these dra...

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, g...

Some components of plant-based meals, such as saponins and vegetal proteins, have been proposed as inducers of intestinal inflammation in some fish. However, the molecular and cellular bases for this phenomenon have not been reported. In this work, zebrafish were used as a model to evaluate the effects of individual soybean meal components, such as...

Vibrio ordalii is the causative agent of atypical vibriosis and has the potential to cause severe losses in salmonid aquaculture. To prevent and control outbreaks, a rapid, reproducible, sensitive, and effective diagnostic method is needed. We evaluated a new conventional polymerase chain reaction (PCR) and real-time PCR (qPCR) protocol using a pri...

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 i...

Feeding strategy scheme. (TIFF)

Monitoring larvae food ingestion. Lateral view of a 7dpf larva before feeding (A) and after food ingestion (B, C). Food ingestion can be easily verified by observing food presence in the gut. (D) Quantification of the number of larvae that eat in every feeding. (TIFF)

Stack on the Z-axis of the midgut of fish fed with soybean meal. Lateral view of a mid-intestine section, from right to left, after 4 days of treatment. As we move towards the center of the bowel, it can be observed that the largest number of neutrophils is located in this zone. The amount of these granulocytes decreases when we move into regions t...

The CSRNP (cystein-serine-rich nuclear protein) transcription factors are conserved from Drosophila to human. Functional studies in mice, through knockout for each of their paralogs, have resulted insufficient to elucidate the function of this family of proteins in vertebrate development. Previously, we described the function of the zebrafish ortho...

csrnp1a knockdown does not affect blood flow. Morphant embryos were incubated in the vasodilator SNAP, and its ability to rescue the reduction of blood cells was analyzed (A, B, C). csrnp1a knockdown phenotype was not rescue by SNAP treatment. (A) Control 100% n = 53; (B) Mo csrnp1a atg 36,8% n = 21/57 of morphant phenotype; (C) Mocsrnp1a atg incub...

csrnp1a morphants exhibit an increase in cell death due to morpholino toxicity which is not responsible for the reduction in blood cells in circulation. We analyzed cell death by acridine orange in embryos injected with control morpholino (A), csrnp1a morpholino (C), p53 morpholino (E), or a mixture of csrnp1a and p53 morpholinos (G). A clear incre...

The excessive use of antibiotics in aquaculture can adversely affect not only the environment, but also fish themselves. In this regard, there is evidence that some antibiotics can activate the immune system and reduce their effectiveness. None of those studies consider in detail the adverse inflammatory effect that the antibiotic remaining in the...

6 days of oxytetracycline exposure does not produce mortality nor adverse effects on larvae. Larvae were incubated during 120 hrs and 144 hrs to ensure that the treatment with oxytetracycline does not produce any detrimental effects on larvae. We did not found phenotypic effects such cerebral edema, bending of the tail (A, D), pericardial edema, ab...

Determination of the oxytetracycline LC50 and maximum sub-lethal concentration. Both, embryos (A) and larvae (B) were incubated in six different oxytetracycline concentrations ranging from 125 ppm to 1500 ppm and monitored every 6 hrs and 24 hrs respectively. The maximum sub-lethal concentration was the one where no mortality or any apparent phenot...

Background: The excessive use of antibiotics in aquaculture can adversely affect not only the environment, but also fish themselves. In this regard, there is evidence that some antibiotics can activate the immune system and reduce their effectiveness. None of those studies consider in detail the adverse inflammatory effect that the antibiotic remai...

Despite considerable progress, the mechanisms that control neural progenitor differentiation and behavior, as well as their functional integration into adult neural circuitry, are far from being understood. Given the complexity of the mammalian brain, non-mammalian models provide an excellent model to study neurogenesis, including both the cellular...

Decreased levels of Prox1 protein in prox1 loss of function embryos. Immunohistochemistry using an anti-Prox1 antibody at 48 hpf (A) Prox1 protein distribution in control embryos in comparison to prox1 MO injected embryos (B) black arrow lens (l); arrowhead diencephalon (d), brown arrow diencephalic-mesencephalic boundary (dmb). Scale bar = 200 mic...

DiAsp staining in control and prox1 loss of function embryos at 72 hpf. As at 48 hpf, also at 60 and 72 hpf, prox1 MO injected embryos still presented a decrease number of DiAsp positive cells in neuromasts in comparison to control embryos at the same developmental stage, indicating that the effect is not due to developmental delay of morphant embr...

The lateral line system in zebrafish is composed of a series of organs called neuromasts, which are distributed over the body surface. Neuromasts contain clusters of hair cells, surrounded by accessory cells. In this report we describe zebrafish prox1 mRNA expression in the migrating primordium and in the neuromasts of the posterior lateral line. F...

The CSRNP (cystein-serine-rich nuclear protein) family has been conserved from Drosophila to human. Although knockout mice for each of the mammalian proteins have been generated, their function during vertebrate development has remained elusive. As an alternative to obtain insights on CSRNP's role in development, we have analysed the expression pat...

Members of the Iroquois (Irx) homeodomain transcription factor gene family have been implicated in a variety of early developmental processes, including neural pre-patterning, tissue differentiation, neural crest development and cranial placode formation. Here, we report that, in zebrafish, the irx4a gene participates in specification of a number o...

Publicación ISI

Genes involved in vertebrate development are unusually enriched for highly conserved non-coding sequence elements. These regions are readily detected in silico, by genome-wide sequence comparisons between different vertebrates, from mammals to fish (phylogenetic footprinting). It follows that sequence conservation must be the result of positive sel...

Recent studies of the genome architecture of vertebrates have uncovered two unforeseen aspects of its organization. First, large regions of the genome, called gene deserts, are devoid of protein-coding sequences and have no obvious biological role. Second, comparative genomics has highlighted the existence of an array of highly conserved non-coding...

Different types of placodes originate at the anterior border of the neural plate but it is still an unresolved question whether individual placodes arise as distinct ectodermal specializations in situ or whether all or a subset of the placodes originate from a common preplacodal field. We have analyzed the expression and function of the homeoprotei...

Genes of the iroquois ( Iro/Irx) family are highly conserved from Drosophila to mammals and they have been implicated in a number of developmental processes. In flies, the Iro genes participate in patterning events in the early larva and in imaginal disk specification. In vertebrates, the Irx genes regulate developmental events during gastrulation,...

Analysis of the 16S rRNA genes retrieved directly from different environments has proven to be a powerful tool that has greatly expanded our knowledge of microbial diversity and phylogeny. It is shown here that sequence similarity between 80 and 100% among 16S rDNAs can be estimated by the electrophoretic migration of their heteroduplexes. This was...