Transcriptional upregulation of the -inositol biosynthesis pathway is enhanced by NFAT5 in hyperosmotically stressed tilapia cells.

Euryhaline fish experience variable osmotic environments requiring physiological adjustments to tolerate elevated salinity. Mozambique tilapia () possess one of the highest salinity tolerance limits of any fish. In tilapia and other euryhaline fish species, the -inositol biosynthesis (MIB) pathway enzymes, -inositol phosphate synthase (MIPS) and inositol monophosphatase 1 (IMPA1.

Effects of CRISPR/Cas9 targeting of the myo-inositol biosynthesis pathway on hyper-osmotic tolerance of tilapia cells.

Myo-inositol is an important compatible osmolyte in vertebrates. This osmolyte is produced by the myo-inositol biosynthesis (MIB) pathway composed of myo-inositol phosphate synthase and inositol monophosphatase. These enzymes are among the highest upregulated proteins in tissues and cell cultures from teleost fish exposed to hyperosmotic conditions indicating high importance of this pathway for tolerating this type of stress.

Cell-based homologous expression system for characterization of environmental effects on transmembrane peptide transport in fish.

All organisms encounter environmental changes that lead to physiological adjustments that could drive evolutionary adaptations. The ability to adjust performance in order to cope with environmental changes depends on the organism's physiological plasticity. These adjustments can be reflected in behavioral, physiological, and molecular changes, which interact and affect each other.

Removal of evolutionarily conserved functional MYC domains in a tilapia cell line using a vector-based CRISPR/Cas9 system.

MYC transcription factors have critical roles in facilitating a variety of cellular functions that have been highly conserved among species during evolution. However, despite circumstantial evidence for an involvement of MYC in animal osmoregulation, mechanistic links between MYC function and osmoregulation are missing. Mozambique tilapia (Oreochromis mossambicus) represents an excellent model system to study these links because it is highly euryhaline and highly tolerant to osmotic (salinity) stress at both the whole organism and cellular levels of biological organization.

Different transcriptomic architecture of the gill epithelia in Nile and Mozambique tilapia after salinity challenge.

Tilapiine fishes of the genus Oreochromis vary in their euryhaline capabilities, therefore inhabiting aquatic environments of different salinities across the African continent. We analyzed the differential gene expression in the gills before and after 6 weeks salinity challenge between the highly tolerant Mozambique tilapia (Oreochromis mossambicus) and the less tolerant Nile tilapia (O. niloticus).

Genome Editing Using the CRISPR-Cas9 System to Generate a Solid-Red Germline of Nile Tilapia ().

In recent years, there has been increasing demand for red tilapia, which are commercial strains of hybrids of different tilapiine species or red variants of highly inbred Nile tilapia. However, red tilapia phenotypes are genetically unstable and affected by environmental factors, resulting in nonuniform coloration with black or dark-red color blotches that reduce their market value. Solute carrier family 45 member 2 (SLC45A2) is a membrane transporter that mediates melanin biosynthesis and is evolutionarily conserved from fish to humans.

Nonlinear effects of environmental salinity on the gill transcriptome versus proteome of Oreochromis niloticus modulate epithelial cell turnover.

A data-independent acquisition (DIA) assay library for targeted quantitation of thousands of Oreochromis niloticus gill proteins using a label- and gel-free workflow was generated and used to compare protein and mRNA abundances. This approach generated complimentary rather than redundant data for 1899 unique genes in gills of tilapia acclimated to freshwater and brackish water. Functional enrichment analyses identified mitochondrial energy metabolism, serine protease and immunity-related functions, and cytoskeleton/ extracellular matrix organization as major processes controlled by salinity in O.

A data-independent acquisition (DIA) assay library for quantitation of environmental effects on the kidney proteome of Oreochromis niloticus.

Interactions of organisms with their environment are complex and environmental regulation at different levels of biological organization is often nonlinear. Therefore, the genotype to phenotype continuum requires study at multiple levels of organization. While studies of transcriptome regulation are now common for many species, quantitative studies of environmental effects on proteomes are needed.

Antibiotic effect and microbiome persistence vary along the European seabass gut.

The constant increase in aquaculture production has led to extensive use of antibiotics as a means to prevent and treat diseases, with adverse implications on the environment, animal health and commensal microbes. Gut microbes are important for the host proper functioning, thus evaluating such impacts is highly crucial. Examining the antibiotic impact on gut segments with different physiological roles may provide insight into their effects on these microhabitats.

Corrigendum: Salinity-Dependent Shift in the Localization of Three Peptide Transporters along the Intestine of the Mozambique Tilapia ().

[This corrects the article DOI: 10.3389/fphys.2017.

Core gut microbial communities are maintained by beneficial interactions and strain variability in fish.

The term core microbiome describes microbes that are consistently present in a particular habitat. If the conditions in that habitat are highly variable, core microbes may also be considered to be ecological generalists. However, little is known about whether metabolic competition and microbial interactions influence the ability of some microbes to persist in the core microbiome while others cannot.

Peptide Transporters in the Primary Gastrointestinal Tract of Pre-Feeding Mozambique Tilapia Larva.

Fish larvae differ greatly from the adult form in their morphology and organ functionality. The functionality of the gastrointestinal tract depends on the expression of various pumps, transporters, and channels responsible for feed digestion and nutrients absorption. During the larval period, the gastrointestinal tract develops from a simple closed tube, into its complex form with differentiated segments, crypts and villi, as found in the adult.

Transcriptome Analysis Reveals Common and Differential Response to Low Temperature Exposure Between Tolerant and Sensitive Blue Tilapia ().

Tilapias are very important to the world's aquaculture. As befitting fish of their tropical origin, their distribution, and culture practices are highly affected by low temperatures. In this study, we used genetic and genomic methodologies to reveal pathways involved in the response and tolerance of blue tilapia () to low temperature stress.

Short- and long-term low-salinity acclimation effects on the branchial and intestinal gene expression in the European seabass (Dicentrarchus labrax).

The European seabass (Dicentrarchus labrax) is a teleost remarkably adapted to a wide range of water salinity, through osmoregulatory mechanisms, mainly operating in the gills and the intestine. As an important aquaculture species, its rearing in low-salinity conditions offers benefits for its inland culture. However, this demands a full comprehension of the European seabass osmoregulatory mechanisms and its response to acclimation protocols.

Host genetic selection for cold tolerance shapes microbiome composition and modulates its response to temperature.

The hologenome concept proposes that microbes and their host organism are an independent unit of selection. Motivated by this concept, we hypothesized that thermal acclimation in poikilothermic organisms, owing to their inability to maintain their body temperature, is connected to their microbiome composition. To test this hypothesis, we used a unique experimental setup with a transgenerational selective breeding scheme for cold tolerance in tropical tilapias.

Dietary salt levels affect digestibility, intestinal gene expression, and the microbiome, in Nile tilapia (Oreochromis niloticus).

Nile tilapia (Oreochromis niloticus) is the world's most widely cultured fish species. Therefore, its nutritional physiology is of great interest from an aquaculture perspective. Studies conducted on several fish species, including tilapia, demonstrated the beneficial effects of dietary salt supplementation on growth; however, the mechanism behind these beneficial effects is still not fully understood.

Effects of the acclimation to high salinity on intestinal ion and peptide transporters in two tilapia species that differ in their salinity tolerance.

Tilapiine species, widely distributed across habitats with diverse water salinities, are important to aquaculture as well as a laboratory model. The effects of water salinity on two tilapia species, that differ in their salinity tolerance, was evaluated. Oreochromis niloticus reared in brackish-water, showed a significant decrease in growth and feed efficiency, whereas O.

Salinity-Dependent Shift in the Localization of Three Peptide Transporters along the Intestine of the Mozambique Tilapia ().

The peptide transporter (PepT) systems are well-known for their importance to protein absorption in all vertebrate species. These symporters use H gradient at the apical membrane of the intestinal epithelial cells to mediate the absorption of small peptides. In fish, the intestine is a multifunctional organ, involved in osmoregulation, acid-base regulation, and nutrient absorption.

Intestinal transcriptome analysis revealed differential salinity adaptation between two tilapiine species.

Tilapias are a group of freshwater species, which vary in their ability to adapt to high salinity water. Osmotic regulation in fish is conducted mainly in the gills, kidney, and gastrointestinal tract (GIT). The mechanisms involved in ion and water transport through the GIT is not well-characterized, with only a few described complexes.

Effects of salinity and prolactin on gene transcript levels of ion transporters, ion pumps and prolactin receptors in Mozambique tilapia intestine.

Euryhaline teleosts are faced with significant challenges during changes in salinity. Osmoregulatory responses to salinity changes are mediated through the neuroendocrine system which directs osmoregulatory tissues to modulate ion transport. Prolactin (PRL) plays a major role in freshwater (FW) osmoregulation by promoting ion uptake in osmoregulatory tissues, including intestine.

Comparative time-course study on pituitary and branchial response to salinity challenge in Mozambique tilapia (Oreochromis mossambicus) and Nile tilapia (O. niloticus).

The physiological response of Mozambique and Nile tilapia transferred from fresh to brackish (15 ppt) water was compared during a one-week time course. Response in the pituitary was measured by the gene expression pattern of prolactin (PRL I), growth hormone (GH), and calcium-sensing receptor (CaSR), while the response in the gills was measured by the gene expression pattern of the prolactin receptor (PRL-R), Na(+)/K(+)/2Cl(-) cotransporter (NKCC) and Na(+)/Cl(-) cotransporter (NCC), and by activity and expression of Na(+)/K(+)-ATPase (NKA). The time-course curves of plasma osmolality levels indicate a rapid elevation 24 h after transfer, which later decreased and maintained at stable level.

Sex-linked markers and microsatellite locus duplication in the cichlid species Oreochromis tanganicae.

Cichlid species of the genus Oreochromis vary in their genetic sex-determination systems. In this study, we used microsatellite DNA markers to characterize the sex-determination system in Oreochromis tanganicae. Markers on linkage group 3 were associated with phenotypic sex, with an inheritance pattern typical of a female heterogametic species (WZ-ZZ).

Amh and Dmrta2 genes map to tilapia (Oreochromis spp.) linkage group 23 within quantitative trait locus regions for sex determination.

Recent studies have revealed that the major genes of the mammalian sex determination pathway are also involved in sex determination of fish. Several studies have reported QTL in various species and strains of tilapia, regions contributing to sex determination have been identified on linkage groups 1, 3, and 23. Genes contributing to sex-specific mortality have been detected on linkage groups 2, 6, and 23.