Synthesis, characterization and supra-molecular analysis for (E)-3-(pyridin-4-yl)acrylic acid.

The title compound, C8H7NO2, crystallizes as prismatic colourless crystals in space group P , with one mol-ecule in the asymmetric unit. The pyridine ring is fused to acrylic acid, forming an almost planar structure with an E-configuration about the double bond with a torsion angle of -6.1 (2)°. In the crystal, strong O-H⋯N inter-actions link the mol-ecules, forming chains along the [101] direction. Weak C-H⋯O inter-actions link adjacent chains along the [100] direction, generating an R 2 2(14) homosynthon. Finally, π-π stacking inter-actions lead to the formation of the three-dimensional structure. The supra-molecular analysis was supported by Hirshfeld surface and two-dimensional fingerprint plot analysis, indicating that the most abundant contacts are associated with H⋯H, O⋯H/H⋯O, N⋯H/H⋯N and C⋯H/H⋯C inter-actions.

Insect vector and reservoir plant of 'Fragaria × ananassa' phyllody phytoplasma (16SrXIII-F) in central region of Chile.

Strawberry phyllody has emerged as a prevalent disease affecting Chilean strawberry in recent years. The causal pathogen, 'Fragaria × ananassa' phyllody phytoplasma (StrPh), is categorized within the 16S ribosomal group XIII, exclusively found in the Americas. In the context of economically significant crops, hemipteran insect vectors and alternative host plants play a pivotal role in their natural dissemination. This study comprehensively examined the key epidemiological facets of StrPh in the central region of Chile: the insect vector and alternative hosts. Through field surveys, we identified an abundance of an insect species, Cixiosoma sp., in an StrPh-infected strawberry field, and confirmed its role as a vector of this phytoplasma through subsequent transmission assays. Moreover, we found a spontaneous weed species, Galega officinalis, to be infected with StrPh, raising the possibility of it being a potential alternative host plant for this phytoplasma. StrPh was also detected in cold-stored strawberry runners purchased from a nursery that supplies the local strawberry cultivation, suggesting a potential source of this phytoplasma in Chile. Collectively, these findings provide a significant epidemiological source of StrPh dissemination in central Chile.

Sex-Biased Transcription Expression of Vitellogenins Reveals Fusion Gene and MicroRNA Regulation in the Sea Louse Caligus rogercresseyi.

The caligid ectoparasite, Caligus rogercresseyi, is one of the main concerns in the Chilean salmon industry. The molecular mechanisms displayed by the parasite during the reproductive process represent an opportunity for developing novel control strategies. Vitellogenin is a multifunctional protein recognized as a critical player in several crustaceans' biological processes, including reproduction, embryonic development, and immune response. This study aimed to characterize the C. rogercresseyi vitellogenins, including discovering novel transcripts and regulatory mechanisms associated with microRNAs. Herein, vitellogenin genes were identified by homology analysis using the reference sea louse genome, transcriptome database, and arthropods vitellogenin-protein database. The validation of expression transcripts was conducted by RNA nanopore sequencing technology. Moreover, fusion gene profiling, miRNA target analysis, and functional validation were performed using luciferase assay. Six putative vitellogenin genes were identified in the C. rogercresseyi genome with high homology with other copepods vitellogenins. Furthermore, miR-996 showed a putative role in regulating the Cr_Vitellogenin1 gene, which is highly expressed in females. Moreover, vitellogenin-fusion genes were identified in adult stages and highly regulated in males, demonstrating sex-related expression patterns. In females, the identified fusion genes merged with several non-vitellogenin genes involved in biological processes of ribosome assembly, BMP signaling pathway, and biosynthetic processes. This study reports the genome array of vitellogenins in C. rogercresseyi for the first time, revealing the putative role of fusion genes and miRNA regulation in sea lice biology.

Alternative splicing in Atlantic salmon head kidney and SHK-1 cell line during the Piscirickettsia salmonis infection: A comparative transcriptome survey.

Piscirickettsia salmonis, an intracellular bacterium in salmon aquaculture, is a big challenge because it is responsible for 54.2% of Atlantic salmon mortalities. In recent years, the high relevance of Alternative Splicing (AS) as a molecular mechanism associated with infectious conditions and host-pathogen interaction processes, especially in host immune activation, has been observed. Several studies have highlighted the role of AS in the host's immune response during viral, bacterial, and endoparasite infection. In the present study, we evaluated AS transcriptome profiles during P. salmonis infection in the two most used study models, SHK-1 cell line and salmon head kidney tissue. First, the SHK-1 cell line was exposed to P. salmonis infection at 0-, 7-, and 14-days post-infection (dpi). Following, total RNA was extracted for Illumina sequencing. On the other hand, RNA-Seq datasets of Atlantic salmon head kidney infected with the same P. salmonis strayingwase used. For both study models, the highest number of differentially alternative splicing (DAS) events was observed at 7 dpi, 16,830 DAS events derived from 9213 DAS genes in SHK-1 cells, and 13,820 DAS events from 7684 DAS genes in salmon HK. Alternative first exon (AF) was the most abundant AS type in the three infection times analyzed, representing 31% in SHK-1 cells and 228.6 in salmon HK; meanwhile, mutually exclusive exon (MX) was the least abundant. Notably, functional annotation of DAS genes in SHK-1 cells infected with P. salmonis showed a high presence of genes related to nucleotide metabolism. In contrast, the salmon head kidney exhibited many GO terms associated with immune response. Our findings reported the role of AS during P. salmonis infection in Atlantic salmon. These studies would contribute to a better understanding of the molecular bases that support the pathogen-host interaction, evidencing the contribution of AS regulating the transcriptional host response.

Role of vitamin C and SVCT2 in neurogenesis.

Different studies have established the fundamental role of vitamin C in proliferation, differentiation, and neurogenesis in embryonic and adult brains, as well as in in vitro cell models. To fulfill these functions, the cells of the nervous system regulate the expression and sorting of sodium-dependent vitamin C transporter 2 (SVCT2), as well as the recycling of vitamin C between ascorbic acid (AA) and dehydroascorbic acid (DHA) via a bystander effect. SVCT2 is a transporter preferentially expressed in neurons and in neural precursor cells. In developmental stages, it is concentrated in the apical region of the radial glia, and in adult life, it is expressed preferentially in motor neurons of the cerebral cortex, starting on postnatal day 1. In neurogenic niches, SVCT2 is preferentially expressed in precursors with intermediate proliferation, where a scorbutic condition reduces neuronal differentiation. Vitamin C is a potent epigenetic regulator in stem cells; thus, it can induce the demethylation of DNA and histone H3K27m3 in the promoter region of genes involved in neurogenesis and differentiation, an effect mediated by Tet1 and Jmjd3 demethylases, respectively. In parallel, it has been shown that vitamin C induces the expression of stem cell-specific microRNA, including the Dlk1-Dio3 imprinting region and miR-143, which promotes stem cell self-renewal and suppresses de novo expression of the methyltransferase gene Dnmt3a. The epigenetic action of vitamin C has also been evaluated during gene reprogramming of human fibroblasts to induced pluripotent cells, where it has been shown that vitamin C substantially improves the efficiency and quality of reprogrammed cells. Thus, for a proper effect of vitamin C on neurogenesis and differentiation, its function as an enzymatic cofactor, modulator of gene expression and antioxidant is essential, as is proper recycling from DHA to AA by various supporting cells in the CNS.

Transcriptome Signatures of Atlantic Salmon-Resistant Phenotypes against Sea Lice Infestation Are Associated with Tissue Repair.

Salmon aquaculture is constantly threatened by pathogens that impact fish health, welfare, and productivity, including the sea louse Caligus rogercresseyi. This marine ectoparasite is mainly controlled through delousing drug treatments that have lost efficacy. Therein, strategies such as salmon breeding selection represent a sustainable alternative to produce fish with resistance to sea lice. This study explored the whole-transcriptome changes in Atlantic salmon families with contrasting resistance phenotypes against lice infestation. In total, 121 Atlantic salmon families were challenged with 35 copepodites per fish and ranked after 14 infestation days. Skin and head kidney tissue from the top two lowest (R) and highest (S) infested families were sequenced by the Illumina platform. Genome-scale transcriptome analysis showed different expression profiles between the phenotypes. Significant differences in chromosome modulation between the R and S families were observed in skin tissue. Notably, the upregulation of genes associated with tissue repairs, such as collagen and myosin, was found in R families. Furthermore, skin tissue of resistant families showed the highest number of genes associated with molecular functions such as ion binding, transferase, and cytokine activity, compared with the susceptible. Interestingly, lncRNAs differentially modulated in the R/S families are located near genes associated with immune response, which are upregulated in the R family. Finally, SNPs variations were identified in both salmon families, where the resistant ones showed the highest number of SNPs variations. Remarkably, among the genes with SPNs, genes associated with the tissue repair process were identified. This study reported Atlantic salmon chromosome regions exclusively expressed in R or S Atlantic salmon families' phenotypes. Furthermore, due to the presence of SNPs and high expression of tissue repair genes in the resistant families, it is possible to suggest mucosal immune activation associated with the Atlantic salmon resistance to sea louse infestation.

Chromosome-Level Genome Assembly of the Blue Mussel Mytilus chilensis Reveals Molecular Signatures Facing the Marine Environment.

The blue mussel Mytilus chilensis is an endemic and key socioeconomic species inhabiting the southern coast of Chile. This bivalve species supports a booming aquaculture industry, which entirely relies on artificially collected seeds from natural beds that are translocated to diverse physical-chemical ocean farming conditions. Furthermore, mussel production is threatened by a broad range of microorganisms, pollution, and environmental stressors that eventually impact its survival and growth. Herein, understanding the genomic basis of the local adaption is pivotal to developing sustainable shellfish aquaculture. We present a high-quality reference genome of M. chilensis, which is the first chromosome-level genome for a Mytilidae member in South America. The assembled genome size was 1.93 Gb, with a contig N50 of 134 Mb. Through Hi-C proximity ligation, 11,868 contigs were clustered, ordered, and assembled into 14 chromosomes in congruence with the karyological evidence. The M. chilensis genome comprises 34,530 genes and 4795 non-coding RNAs. A total of 57% of the genome contains repetitive sequences with predominancy of LTR-retrotransposons and unknown elements. Comparative genome analysis of M. chilensis and M. coruscus was conducted, revealing genic rearrangements distributed into the whole genome. Notably, transposable Steamer-like elements associated with horizontal transmissible cancer were explored in reference genomes, suggesting putative relationships at the chromosome level in Bivalvia. Genome expression analysis was also conducted, showing putative genomic differences between two ecologically different mussel populations. The evidence suggests that local genome adaptation and physiological plasticity can be analyzed to develop sustainable mussel production. The genome of M. chilensis provides pivotal molecular knowledge for the Mytilus complex.

Comparative Transcriptomics in Atlantic Salmon Head Kidney and SHK-1 Cell Line Exposed to the Sea Louse Cr-Cathepsin.

The development of vaccines against sea lice in salmon farming is complex, expensive, and takes several years for commercial availability. Recently, transcriptome studies in sea louse have provided valuable information for identifying relevant molecules with potential use for fish vaccines. However, the bottleneck is the in vivo testing of recombinant protein candidates, the dosage, and the polyvalent formulation strategies. This study explored a cell-based approach to prospect antigens as candidate vaccines against sea lice by comparison with immunized fish. Herein, SHK-1 cells and Atlantic salmon head kidney tissue were exposed to the antigen cathepsin identified from the sea louse Caligus rogercresseyi. The cathepsin protein was cloned and recombinantly expressed in Escherichia coli, and then SHK-1 cell lines were stimulated with 100 ng/mL cathepsin recombinant for 24 h. In addition, Atlantic salmons were vaccinated with 30 ug/mL recombinant protein, and head kidney samples were then collected 30 days post-immunization. SHK-1 cells and salmon head kidney exposed to cathepsin were analyzed by Illumina RNA sequencing. The statistical comparisons showed differences in the transcriptomic profiles between SHK-1 cells and the salmon head kidney. However, 24.15% of the differentially expressed genes were shared. Moreover, putative gene regulation through lncRNAs revealed tissue-specific transcription patterns. The top 50 up and downregulated lncRNAs were highly correlated with genes involved in immune response, iron homeostasis, pro-inflammatory cytokines, and apoptosis. Also, highly enriched pathways related to the immune system and signal transduction were shared between both tissues. These findings highlight a novel approach to evaluating candidate antigens for sea lice vaccine development, improving the antigens screening in the SHK-1 cell line model.

Modelling a dynamic magneto-agglutination bioassay.

The process of developing an end-to-end model of a magneto-immunoassay is described, simulating the agglutination effect due to the specific binding of bacteria to paramagnetic particles. After establishing the properties of the dose-specific agglutination through direct imaging, a microfluidic assay was used to demonstrate changes in the magnetophoretic transport dynamics of agglutinated clusters via transient inductive magentometer measurements. End-to-end mathematical modelling is used to establish the physical processes underlying the assay. First, a modified form of Becker-Döring nucleation kinetic equations is used to establish a relationship between analyte dose and average cluster size. Next, Stokes flow equations are used to establish a relationship between cluster size and speed of motion within the fluid chamber. This predicts a cluster-size dynamic profile of concentration of PMPs versus time when the magnetic field is switched between the two actuated magnets. Finally, inductive modelling is carried out to predict the response of the magnetometer circuit in response to the dynamics of magnetic clusters. The predictions of this model are shown to agree well with the results of experiments, and to predict the shape of the dose-response curve.

Calidad de vida relacionada con la salud bucal y factores asociados en pacientes con bruxismo / Quality of life related to oral health and associated factors in patients with bruxism

RESUMEN Introducción: El bruxismo es una actividad parafuncional que puede tener impacto en la calidad de vida de las personas. Su etiología es diversa y por ello puede tener influencia de diferentes factores. Objetivo: Evaluar el impacto en la calidad de vida relacionada con la salud bucal y factores asociados en pacientes con bruxismo, atendidos en clínicas de practica de la Facultad de Odontología sede Medellín-Envigado, de la Universidad Cooperativa de Colombia. Métodos: Estudio observacional transversal y analítico con una muestra no probabilística de 51 pacientes entre 18 y 60 años que acudieron a consulta programada, atendidos en clínicas de practica de la Facultad de Odontología en Envigado, de la Universidad Cooperativa de Colombia, se realizaron exámenes clínicos, anamnesis y encuesta sociodemográfica, posteriormente se aplicó cuestionario OHIP-14 sobre calidad de vida relacionada con la salud bucal. Se realizó un análisis univariado y bivariado. Resultados: en los pacientes con bruxismo el índice OHIP-14 evidenció que la limitación funcional y el dolor físico obtuvieron un valor máximo de 6.00 puntos. Además, los ítems de discapacidad y malestar psicológico presentaban puntuación medianamente alta (4.00 y 5.00 puntos respectivamente). Al evaluar otros factores, solo se encuentran diferencias con significación estadística para los aspectos demográficos y socioeconómicos en algunos dominios (Vp=0,012). Conclusión: Los pacientes con bruxismo tuvieron un impacto negativo en la calidad de vida relacionada con la salud bucal.

ABSTRACT Introduction: Bruxism is a parafunctional activity that can have an impact on people's quality of life. Its etiology is diverse and therefore it can be influenced by different factors. Objective: To evaluate the impact on the quality of life related to oral health and associated factors in patients with bruxism, attended in the practices clinics of the Faculty of Dentistry, at the Universidad Cooperativa de Colombia sectional Medellín-Envigado. Methods: Cross-sectional and analytical observational study with a non-probability sample of 51 patients between 18 and 60 years of age who attended a scheduled consultation, attended in the practices clinics of the Faculty of Dentistry, at the Cooperative University of Colombia, Medellin-Envigado. Clinical exams, anamnesis and sociodemographic survey were carried out, subsequently an OHIP-14 survey on quality of life related to oral health was applied. A univariate and bivariate analysis was performed. Results: in patients with bruxism the OHIP-14 index showed that functional limitation and physical pain obtained a maximum value of 6.00 points. In addition, the items of disability and psychological distress presented a fairly high score (4.00 and 5.00 points respectively). When evaluating other factors, differences with statistical significance were found only for demographic and socioeconomic aspects in some domains (Vp = 0.012). Conclusion: Patients with bruxism had a negative impact on quality of life related to oral health.

Dual RNA-Seq Analysis Reveals Transcriptome Effects during the Salmon-Louse Interaction in Fish Immunized with Three Lice Vaccines.

Due to the reduced efficacy of delousing drugs used for sea lice control in salmon aquaculture, fish vaccines have emerged as one of the most sustainable strategies in animal health. Herein, the availability of C. rogercresseyi and Salmo salar genomes increases the capability of identifying new candidate antigens for lice vaccines using RNA sequencing and computational tools. This study aimed to evaluate the effects of two recombinant antigens characterized as peritrophin and cathepsin proteins on the transcriptome profiling of Atlantic salmon during a sea lice infestation. Four experimental groups were used: Peritrophin, cathepsin, and peritrophin/cathepsin (P/C), and PBS as the control. C. rogercresseyi female, S. salar head kidney, and skin tissue samples were sampled at 25 days post-infestation (dpi) for Illumina sequencing and RNA-seq analysis. Differential gene expression, gene ontology, and chromosomal expression analyses were performed. Furthermore, the dual RNA-seq analysis approach was performed to simultaneously explore host and pathogen transcriptomes, identifying functional associations for vaccine design. The morphometry of female sea lice exposed to immunized fish was also evaluated. The RNA-Seq analysis exhibited prototype-dependent transcriptome modulation, showing a conspicuous competition for metal ions during the infestation. Moreover, Dual RNA-seq analysis revealed vaccine-dependent gene patterns in both the host and the pathogen. Notably, significant morphometric differences between lice collected from immunized and control fish were observed, where cathepsin and P/C showed 57% efficacy. This study showed the potential of two proteins as lice vaccines for the salmon industry, suggesting novel molecular mechanisms between host-parasite interactions.

Peritrophin-like Genes Are Associated with Delousing Drug Response and Sensitivity in the Sea Louse Caligus rogercresseyi.

Caligus rogercresseyi is the main ectoparasite that affects the salmon industry in Chile. The mechanisms used by the parasite to support its life strategy are of great interest for developing control strategies. Due to the critical role of insect peritrophins in host-parasite interactions and response to pest control drugs, this study aimed to identify and characterize the peritrophin-like genes present in C. rogercresseyi. Moreover, the expression of peritrophin-like genes was evaluated on parasites exposed to delousing drugs such as pyrethroids and azamethiphos. Peritrophin genes were identified by homology analysis among the sea louse transcriptome database and arthropods peritrophin-protein database obtained from GenBank and UniProt. Moreover, the gene loci in the parasite genome were located. Furthermore, peritrophin gene expression levels were evaluated by RNA-Seq analysis in sea louse developmental stages and sea lice exposed to delousing drugs deltamethrin, cypermethrin, and azamethiphos. Seven putative peritrophin-like genes were identified in C. rogercresseyi with high homology with other crustacean peritrophins. Differences in the presence of signal peptides, the number of chitin-binding domains, and the position of conserved cysteines were found. In addition, seven peritrophin-like gene sequences were identified in the C. rogercresseyi genome. Gene expression analysis revealed a stage-dependent expression profile. Notably, differential regulation of peritrophin genes in resistant and susceptible populations to delousing drugs was found. These data are the first report and characterization of peritrophin genes in the sea louse C. rogercresseyi, representing valuable knowledge to understand sea louse biology. Moreover, this study provides evidence for a deeper understanding of the molecular basis of C. rogercresseyi response to delousing drugs.

Exploring Sea Lice Vaccines against Early Stages of Infestation in Atlantic Salmon (Salmo salar).

The sea louse Caligus rogercresseyi genome has opened the opportunity to apply the reverse vaccinology strategy for identifying antigens with potential effects on lice development and its application in sea lice control. This study aimed to explore the efficacy of three sea lice vaccines against the early stage of infestation, assessing the transcriptome modulation of immunized Atlantic salmon. Therein, three experimental groups of Salmo salar (Atlantic salmon) were vaccinated with the recombinant proteins: Peritrophin (prototype A), Cathepsin (prototype B), and the mix of them (prototype C), respectively. Sea lice infestation was evaluated during chalimus I-II, the early-infective stages attached at 7-days post infestation. In parallel, head kidney and skin tissue samples were taken for mRNA Illumina sequencing. Relative expression analyses of genes were conducted to identify immune responses, iron transport, and stress responses associated with the tested vaccines during the early stages of sea lice infection. The vaccine prototypes A, B, and C reduced the parasite burden by 24, 44, and 52% compared with the control group. In addition, the RNA-Seq analysis exhibited a prototype-dependent transcriptome modulation. The high expression differences were observed in genes associated with metal ion binding, molecular processes, and energy production. The findings suggest a balance between the host's inflammatory response and metabolic process in vaccinated fish, increasing their transcriptional activity, which can alter the early host-parasite interactions. This study uncovers molecular responses produced by three vaccine prototypes at the early stages of infestation, providing new knowledge for sea lice control in the salmon aquaculture.

Competing endogenous RNA-networks reveal key regulatory microRNAs involved in the response of Atlantic salmon to a novel orthomyxovirus.

One of the most intriguing discoveries of the genomic era is that only a small fraction of the genome is dedicated to protein coding. The remaining fraction of the genome contains, amongst other elements, a number of non-coding transcripts that regulate the transcription of protein coding genes. Here we used transcriptome sequencing data to explore these gene regulatory networks using RNA derived from gill tissue of Atlantic salmon (Salmo salar) infected with Pilchard orthomyxovirus (POMV), but showing no clinical signs of disease. We examined fish sampled early during the challenge trial (8-12 days after infection) to uncover potential biomarkers of early infection and innate immunity, and fish sampled late during the challenge trial (19 dpi) to elucidate potential markers of resistance to POMV. We analysed total RNA-sequencing data to find differentially expressed messenger RNAs (mRNA) and identify new long-noncoding RNAs (lncRNAs). We also evaluated small RNA sequencing data to find differentially transcribed microRNAs (miRNAs) and explore their role in gene regulatory networks. Whole-genome expression data (both coding and non-coding transcripts) were used to explore the crosstalk between RNA molecules by constructing competing endogenous RNA networks (ceRNA). The teleost specific miR-462/miR-731 cluster was strongly induced in POMV infected fish and deemed a potential biomarker of early infection. Gene networks also identified a selenoprotein (selja), downregulated in fish sampled late during the challenge, which may be associated to viral clearance and the return to homeostasis after infection. This study provides the basis for further investigations using molecular tools to overexpress or inhibit miRNAs to confirm the functional impact of the interactions presented here on gene expression and their potential application at commercial level.

Proximity ligation strategy for the genomic reconstruction of microbial communities associated with the ectoparasite Caligus rogercresseyi.

The sea louse Caligus rogercresseyi has become one of the main constraints for the sustainable development of salmon aquaculture in Chile. Although this parasite's negative impacts are well recognized by the industry, some novel potential threats remain unnoticed. The recent sequencing of the C. rogercresseyi genome revealed a large bacterial community associated with the sea louse, however, it is unknown if these microorganisms should become a new focus of sanitary concern. Herein, chromosome proximity ligation (Hi-C) coupled with long-read sequencing were used for the genomic reconstruction of the C. rogercresseyi microbiota. Through deconvolution analysis, we were able to assemble and characterize 413 bacterial genome clusters, including six bacterial genomes with more than 80% of completeness. The most represented bacterial genome belonged to the fish pathogen Tenacibacullum ovolyticum (97.87% completeness), followed by Dokdonia sp. (96.71% completeness). This completeness allowed identifying 21 virulence factors (VF) within the T. ovolyticum genome and four antibiotic resistance genes (ARG). Notably, genomic pathway reconstruction analysis suggests putative metabolic complementation mechanisms between C. rogercresseyi and its associated microbiota. Taken together, our data highlight the relevance of Hi-C techniques to discover pathogenic bacteria, VF, and ARGs and also suggest novel host-microbiota mutualism in sea lice biology.

Atlantic Salmon (Salmo salar) Transfer to Seawater by Gradual Salinity Changes Exhibited an Increase in The Intestinal Microbial Abundance and Richness.

The host's physiological history and environment determine the microbiome structure. In that sense, the strategy used for the salmon transfer to seawater after parr-smolt transformation may influence the Atlantic salmon's intestinal microbiota. Therefore, this study aimed to explore the diversity and abundance of the Atlantic salmon intestinal microbiota and metagenome functional prediction during seawater transfer under three treatments. One group was exposed to gradual salinity change (GSC), the other to salinity shock (SS), and the third was fed with a functional diet (FD) before the seawater (SW) transfer. The microbial profile was assessed through full-16S rRNA gene sequencing using the Nanopore platform. In addition, metagenome functional prediction was performed using PICRUSt2. The results showed an influence of salinity changes on Atlantic salmon gut microbiota richness, diversity, and taxonomic composition. The findings reveal that GSC and the FD increased the Atlantic salmon smolt microbiota diversity, suggesting a positive association between the intestinal microbial community and fish health during seawater transfer. The reported knowledge can be applied to surveil the microbiome in smolt fish production, improving the performance of Atlantic salmon to seawater transfer.

Trypsin Genes Are Regulated through the miRNA Bantam and Associated with Drug Sensitivity in the Sea Louse Caligus rogercresseyi.

The role of trypsin genes in pharmacological sensitivity has been described in numerous arthropod species, including the sea louse Caligus rogercresseyi. This ectoparasite species is mainly controlled by xenobiotic drugs in Atlantic salmon farming. However, the post-transcriptional regulation of trypsin genes and the molecular components involved in drug response remain unclear. In particular, the miRNA bantam family has previously been associated with drug response in arthropods and is also found in C. rogercresseyi, showing a high diversity of isomiRs. This study aimed to uncover molecular interactions among trypsin genes and bantam miRNAs in the sea louse C. rogercresseyi in response to delousing drugs. Herein, putative mRNA/miRNA sequences were identified and localized in the C. rogercresseyi genome through genome mapping and blast analyses. Expression analyses were obtained from the mRNA transcriptome and small-RNA libraries from groups with differential sensitivity to three drugs used as anti-sea lice agents: azamethiphos, deltamethrin, and cypermethrin. The validation was conducted by qPCR analyses and luciferase assay of selected bantam and trypsin genes identified from in silico transcript prediction. A total of 60 trypsin genes were identified in the C. rogercresseyi genome, and 39 bantam miRNAs were differentially expressed in response to drug exposure. Notably, expression analyses and correlation among values obtained from trypsin and bantam revealed an opposite trend and potential binding sites with significant ΔG values. The luciferase assay showed a reduction of around 50% in the expression levels of the trypsin 2-like gene, which could imply that this gene is a potential target for bantam. The role of trypsin genes and bantam miRNAs in the pharmacological sensitivity of sea lice and the use of miRNAs as potential markers in these parasites are discussed in this study.

Comprehensive Transcriptome Analyses in Sea Louse Reveal Novel Delousing Drug Responses Through MicroRNA regulation.

The role of miRNAs in pharmacological responses through gene regulation related to drug metabolism and the detoxification system has recently been determined for terrestrial species. However, studies on marine ectoparasites have scarcely been conducted to investigate the molecular mechanisms of pesticide resistance. Herein, we explored the sea louse Caligus rogercresseyi miRNome responses exposed to delousing drugs and the interplaying with coding/non-coding RNAs. Drug sensitivity in sea lice was tested by in vitro bioassays for the pesticides azamethiphos, deltamethrin, and cypermethrin. Ectoparasites strains with contrasting susceptibility to these compounds were used. Small-RNA sequencing was conducted, identifying 2776 novel annotated miRNAs, where 163 mature miRNAs were differentially expressed in response to the drug testing. Notably, putative binding sites for miRNAs were found in the ADME genes associated with the drugs' absorption, distribution, metabolism, and excretion. Interactions between the miRNAs and long non-coding RNAs (lncRNAs) were also found, suggesting putative molecular gene regulation mechanisms. This study reports putative miRNAs correlated to the coding/non-coding RNAs modulation, revealing novel pharmacological mechanisms associated with drug resistance in sea lice species.

Transcriptome and morphological analysis in Caligus rogercresseyi uncover the effects of Atlantic salmon vaccination with IPath®.

It is known that iron transporter proteins and their regulation can modulate the fish's immune system, suggesting these proteins as a potential candidate for fish vaccines. Previous studies have evidenced the effects of Atlantic salmon immunized with the chimeric iron-related protein named IPath® against bacterial and ectoparasitic infections. The present study aimed to explore the transcriptome modulation and the morphology of the sea louse Caligus rogercresseyi in response to Atlantic salmon injected with IPath®. Herein, Atlantic salmon were injected with IPath® and challenged to sea lice in controlled laboratory conditions. Then, female adults were collected after 25 days post-infection for molecular and morphological evaluation. Transcriptome analysis conducted in lice collected from immunized fish revealed high modulation of transcripts compared with the control groups. Notably, the low number of up/downregulated transcripts was mainly found in lice exposed to the IPath® fish group. Among the top-25 differentially expressed genes, Vitellogenin, Cytochrome oxidases, and proteases genes were strongly downregulated, suggesting that IPath® can alter lipid transport, hydrogen ion transmembrane transport, and proteolysis. The morphological analysis in lice collected from IPath® fish revealed abnormal embryogenesis and inflammatory processes of the genital segment. Furthermore, head kidney, spleen, and skin were also analyzed in immunized fish to evaluate the transcription expression of immune and iron homeostasis-related genes. The results showed downregulation of TLR22, MCHII, IL-1ß, ALAs, HO, BLVr, GSHPx, and Ferritin genes in head kidney and skin tissues; meanwhile, those genes did not show significant differences in spleen tissue. Overall, our findings suggest that IPath® can be used to enhance the fish immune response, showing a promissory commercial application against lice infections.