Distant Fish Species Research Articles

Fish Allergy Around the World-Precise Diagnosis to Facilitate Patient Management.

The accurate and precise diagnosis of IgE-mediated fish allergy is one of the biggest challenges in allergy diagnostics. A wide range of fish species that belong to evolutionary distant classes are consumed globally. Moreover, each fish species may contain multiple isoforms of a given allergen that often differ in their allergenicity. Recent studies indicated that the cross-reactivity between different fish species is limited in some cases and depends on the evolutionary conservation of the involved allergens. Fish allergens belong to several protein families with different levels of stability to food processing. Additionally, different preparation methods may contribute to specific sensitization patterns to specific fish species and allergens in different geographic regions. Here, we review the challenges and opportunities for improved diagnostic approaches to fish allergy. Current diagnostic shortcomings include the absence of important region-specific fish species in commercial in vitro and in vivo tests as well as the lack of their standardization as has been recently demonstrated for skin prick test solutions. These diagnostic shortcomings may compromise patients' safety by missing some of the relevant species and yielding false negative test results. In contrast, the avoidance of all fish as a common management approach is usually not necessary as many patients may be only sensitized to specific species and allergens. Although food challenges remain the gold standard, other diagnostic approaches are investigated such as the basophil activation test. In the context of molecular allergy diagnosis, we discuss the usefulness of single allergens and raw and heated fish extracts. Recent developments such as allergen microarrays offer the possibility to simultaneously quantify serum IgE specific to multiple allergens and allergen sources. Such multiplex platforms may be used in the future to design diagnostic allergen panels covering evolutionary distant fish species and allergens relevant for particular geographic regions.

Genomic evidence supports the introgression between two sympatric stickleback species inhabiting the White Sea basin

Interspecies hybridization is driven by a complex interplay of factors where introgression plays an important role. In the present study, the transfer of genetic material, between two quite distant fish species from different genera, through spontaneous hybridization was documented with dedicated molecular and bioinformatics tools. We investigate the genomic landscape of putative stickleback-relative introgression by carefully analyzing the tractable transposable elements (TE) on the admixed genome of some individuals of two sympatric stickleback species inhabiting northwestern Russia, namely the three-spined (Gasterosteus aculeatus) and the nine-spined (Pungitius pungitius) sticklebacks. Our data revealed that unique TE amplification types exist, supporting our proposed hypothesis that infers on the interspecific introgression. By running a restriction site-associated DNA sequencing (RAD-Seq) with eight samples of G. aculeatus and P. pungitius and subjecting further the results to a contrasting analysis by variated bioinformatic tools, we identified the related introgression-linked markers. The admixture nature observed in a single sample of the nine-spined stickleback demonstrated the possible traces of remote introgression between these two species. Our work reveals the potential that introgression has on providing particular variants at a high-frequency speed while linking blocks of sequence with multiple functional mutations. However, even though our results are of significant interest, an increased number of samples displaying the introgression are required to further ascertain our conclusions.

Impacts of subchronic exposure to a commercial 2,4-D herbicide on developmental stages of multiple freshwater fish species

Invasive, nuisance aquatic species such as Eurasian watermilfoil (Myriophyllum spicatum) are rapidly spreading across the United States. One common active ingredient used to control this invasive species is 2,4-Dichlorophenoxyacetic acid (2,4-D). Application of 2,4-D to aquatic environments typically occurs while many freshwater fish are spawning and due to 2,4-D stability in aquatic environments, many non-target species experience prolonged exposure throughout embryogenesis and larval development. The impacts of 2,4-D exposure on phylogenetically distant fish species is poorly understood. Herein, we investigated the impacts of the 2,4-D commercial herbicide DMA4®IVM on nine freshwater fish species from six different families (four orders) at different points during ontogeny. Each species was exposed to ecologically relevant concentrations of a commercial 2,4-D herbicide (0.05, 0.50, and 2.00 ppm or mg/L 2,4-D a. e.), and effects on morphology, survival, and growth were evaluated. Our results demonstrate that exposure of embryonic and larval fish to ecologically relevant concentrations of a commercial 2,4-D herbicide reduced survival in early developmental stages of six freshwater species that spanned five phylogenetic families and three phylogenetic orders; however, sensitivity to 2,4-D exposure did not show correlation with phylogenetic proximity. Altogether, our results indicate that the use of 2,4-D herbicides in aquatic ecosystems at current recommended concentrations (≤2 ppm whole-lake treatment) could present risk to multiple freshwater fish species survival during early development.

Locus-specific EPIC-PCR primers for four distinct calmodulin genes of the Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel, 1844)

Nucleotide sequences of four distinct calmodulin genes (designated as CaM-A to -D) of the Pacific bluefin tuna (Thunnus orientalis) were compared. Nucleotide sequence divergence between the coding regions of four genes ranged from 16.0 to 21.6%, and locus-specific eight primer pairs targeting introns were designed. These primer pairs amplified expected size of fragments in five congeneric tuna species, and utility of these primer pairs was investigated using distant fish species.

Microbial Diversity and Parasitic Load in Tropical Fish of Different Environmental Conditions.

In this study we analysed fecal bacterial communities and parasites of three important Indonesian fish species, Epinephelus fuscoguttatus, Epinephelus sexfasciatus and Atule mate. We then compared the biodiversity of bacterial communities and parasites of these three fish species collected in highly polluted Jakarta Bay with those collected in less polluted Indonesian areas of Cilacap (E. sexfasciatus, A. mate) and Thousand Islands (E. fuscoguttatus). In addition, E. fuscoguttatus from net cages in an open water mariculture facility was compared with free living E. fuscoguttatus from its surroundings. Both core and shared microbiomes were investigated. Our results reveal that, while the core microbiomes of all three fish species were composed of fairly the same classes of bacteria, the proportions of these bacterial classes strongly varied. The microbial composition of phylogenetically distant fish species, i.e. A. mate and E. sexfasciatus from Jakarta Bay and Cilacap were more closely related than the microbial composition of more phylogentically closer species, i.e. E. fuscoguttatus, E. sexfasciatus from Jakarta Bay, Cilacap and Thousand Islands. In addition, we detected a weak negative correlation between the load of selected bacterial pathogens, i.e. Vibrio sp. and Photobacterium sp. and the number of endoparasites. In the case of Flavobacterium sp. the opposite was observed, i.e. a weak positive correlation. Of the three recorded pathogenic bacterial genera, Vibrio sp. was commonly found in E. fuscoguttatus from mariculture, and lessly in the vicinity of the net cages and rarely in the fishes from the heavily polluted waters from Jakarta Bay. Flavobacterium sp. showed higher counts in mariculture fish and Photobacteria sp. was the most prominent in fish inside and close to the net cages.

Enzyme activity in energy supply of spermatozoon motility in two taxonomically distant fish species (sterlet Acipenser ruthenus, Acipenseriformes and common carp Cyprinus carpio, Cypriniformes)

As spermatozoon motility duration differs significantly among fish species, the mechanism of ATP generation-regeneration and its distribution along the flagellum may be species-dependent. The present study compared the role of creatine kinase (CK) with that of adenylate kinase (AK) in ATP regeneration during motility of demembranated spermatozoa of taxonomically distant fish species, sterlet, and common carp, allowing investigation for the presence of the creatine-phosphocreatine (PCr) shuttle in sterlet spermatozoa. The flagellar beat frequency of demembranated spermatozoa was measured in reactivating media in the presence or absence of ATP, ADP, PCr, and CK and AK inhibitors. After demembranation, AK, CK, and total ATPase activity was measured in spermatozoon extracts. Beat frequency of demembranated spermatozoa was found to be positively correlated with ATP levels in reactivating medium and to reach a plateau at 0.8 mM and 0.6 mM ATP for carp and sterlet, respectively. It was shown for the first time that sterlet axonemal dynein ATPases have a higher affinity for ATP than do those of carp. Supplementation of reactivating medium with ADP and PCr without ATP resulted in beat frequencies comparable to that measured with 0.3 to 0.5-mM ATP for both studied species. The presence of the PCr-CK phosphagen system and its essential role in ATP regeneration were first confirmed for sturgeon spermatozoa. The inhibition of CK exerted a high impact on spermatozoon energy supply in both species, whereas the inhibition of AK was more pronounced in sterlet than in carp. This was confirmed by the quantification of enzyme activity in spermatozoon extracts. We concluded that spermatozoa of these taxonomically distant species use similar systems to supply energy for flagella motility, but with different efficacy.

Evidence of female preference for hidden sex signals in distant fish species

Lay summary:Many animals use chemical signals (i.e. pheromones) to select a suitable mate during reproduction. However, animals can have hidden preferences forsex signals of other species outside their species natural range of variation.Here we show attraction to sex chemical signal in two distant species of nest guarding fishes. If geographically isolated species were reunited through translocation, these hidden preferences could represent a risk of pheromone pollution and lead to hybridization.

Differential regulation of cathelicidin in salmon and cod

Antimicrobial peptides (AMPs) are an important component of innate immunity in vertebrates. The cathelicidin family of AMPs is well characterized in mammals and has also been reported in several fish species. In this study we investigated the regulation of cathelicidin expression in a gadoid and a salmonid cell-line in order to dissect the signalling pathways involved. For this, fish cells were treated with microbial lysates, purified microbial components and commercial signalling inhibitors and expression of cathelicidin was assessed with quantitative real-time PCR (qPCR). We found that cathelicidin expression was induced in both cell lines in response to microbial stimuli, but the response patterns differed in these evolutionary distant fish species. Our data suggest that in salmonids, pattern recognition receptors such as TLR5 may be involved in the stimulation of cathelicidin expression and that the signalling cascade can include PI3-kinase and cellular trafficking compartments. A detailed knowledge of the regulating factors involved in AMP-related defence responses, including cathelicidin, could help in developing strategies to enhance the immune defence of fish.

Evidence for the Possible Existence of a Remnant L-gulono-gamma-lactone Oxidase (GULO) Gene in a Teleost Genome

DNA fragments related to the cloudy catshark Scyliorhinus torazame L-gulono-gamma-lactone oxidase (GULO) cDNA were detected in a distant fish species. Although the Southern hybridization pattern was more distinct in species with active GULO, DNA fragments related to the GULO gene were also discovered in the common carp Cyprinus carpio. Additionally, in the common carp, inter-individual variation of the hybridization pattern was observed. Regular screening of available teleost fish gene libraries did not reveal GULO related DNA sequences.

Genetic Stability of Progeny from an Artificial Allotetraploid Carp Using Sperm from Five Fish Species

Microsatellite markers and D-loop sequences of mtDNA from a female allotetraploid parent carp and her progenies of generations 1 and 2 induced by sperm of five distant fish species were analyzed. Eleven microsatellite markers were used to identify 48 alleles from the allotetraploid female. The same number of alleles (48) appeared in the first and second generations of the gynogenetic offspring, regardless of the source of the sperm used as an activator. The mtDNA D-loop analysis was performed on the female tetraploid parent, 25 gynogenetic offspring, and 5 sperm-donor species. Fourteen variable sites from the 1,018 bp sequences were observed in the offspring as compared to the female tetraploid parent. Results from D-loop sequence and microsatellite marker analysis showed exclusive maternal transmission, and no genetic information was derived from the father. Our study suggests that progenies of artificial tetraploid carp are genetically stable, which is important for genetic breeding of this tetraploid fish.

Multiple and highly divergent IL-11 genes in teleost fish

Interleukin-11 (IL-11) is a key cytokine in the regulation of proliferation and differentiation of hematopoietic progenitors and is also involved in bone formation, adipogenesis, and protection of mucosal epithelia. Despite this prominent role in diverse physiological processes, IL-11 has been described in only four mammalian species, and recently, in rainbow trout (Oncorhynchus mykiss). Here we report the presence of IL-11 in common carp (Cyprinus carpio), a bony fish species related to zebrafish. IL-11 is expressed in most carp organs and tissues. In vitro expression of IL-11 in cultured macrophages is enhanced by stimulation with lipopolysaccharide and is markedly inhibited by cortisol. A detailed and systematic scan of several fish genome databases confirms that IL-11 is present in all fish, but also reveals the presence of a second, substantially different IL-11 gene in the genomes of phylogenetically distant fish species. We designated both fish paralogues IL-11a and IL-11b. Although sequence identity between fish IL-11a and IL-11b peptides is low, the conservation of their gene structures supplemented by phylogenetic analyses clearly illustrate the orthology of both IL-11a and IL-11b genes of fish with mammalian IL-11. The presence of IL-11 genes in fish demonstrates its importance throughout vertebrate evolution, although the presence of duplicate and divergent IL-11 genes differs from the single IL-11 gene that exists in mammals.

The DNA sequence and biology of human chromosome 19.

Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G + C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

Transmission Ecology and Larval Behaviour of Camallanus cotti (Nematoda, Camallanidae) Under Aquarium Conditions

The parasitic fish nematode Camallanus cotti has been reported from a number of freshwater fish species around the world. Its wide geographical distribution seems mainly to be the result of anthropogenic dissemination due to extensive ornamental fish trade. In most reports it is assumed that C. cotti's life cycle involves cyclopoid copepods as intermediate host and various freshwater fishes as final host. However, the species' relatively frequent and persistent occurrence in aquaria worldwide strongly indicates flexibility in its life cycle, i.e. the ability to infect the final host directly. The present study has shown that under aquaria conditions, without any presence of copepods, C. cotti is able to infect various phylogenetically distant fish species directly for at least three generations. It was further shown that the infective free-living first-stage larvae may survive for more than three weeks in the host-external environment and that their host-attracting behaviour is not precluding direct transmission to the final fish host. Any treatment for C. cotti under aquaculture or aquarium conditions should be directed towards both individual infected fish hosts as well as the free-living larvae on the substrate.