Effects of haloperidol on peripheral erythrocytes and brain neurotransmitter levels of juvenile African Sharptooth Catfish Clarias gariepinus.

OBJECTIVE: The study investigated the effects of haloperidol on peripheral erythrocytes and brain neurotransmitter levels of juvenile African Sharptooth Catfish Clarias gariepinus. METHODS: Juveniles were exposed to different concentrations of haloperidol (0.12, 0.24, and 0.48 mg/L) for 15 days and subsequently withdrawn from the drug for 5 days. Blood samples from the fish on days 1, 5, 10, and 15 and after the 5-day withdrawal period were analyzed for mutagenic changes, after which the fish were sacrificed. The brain was sampled for serotonergic and dopaminergic analyses. RESULT: There was formation of micronuclei in the peripheral fish blood, which increased as the duration and concentrations of the drug increased. The drug significantly reduced the serotonin activity but increased dopamine activity. Some of the studied parameters, however, recovered from the effects of the drug after the 5-day withdrawal period. CONCLUSION: Haloperidol is toxic to fish, and its use in the environment should be guarded to avoid adverse impacts on nontarget species like fish.

Differentially expressed transcripts of Tetracapsuloides bryosalmonae (Cnidaria) between carrier and dead-end hosts involved in key biological processes: novel insights from a coupled approach of FACS and RNA sequencing.

Tetracapsuloides bryosalmonae is a malacosporean endoparasite that infects a wide range of salmonids and causes proliferative kidney disease (PKD). Brown trout serves as a carrier host whereas rainbow trout represents a dead-end host. We thus asked if the parasite adapts to the different hosts by changing molecular mechanisms. We used fluorescent activated cell sorting (FACS) to isolate parasites from the kidney of brown trout and rainbow trout following experimental infection with T. bryosalmonae. The sorted parasite cells were then subjected to RNA sequencing. By this approach, we identified 1120 parasite transcripts that were expressed differentially in parasites derived from brown trout and rainbow trout. We found elevated levels of transcripts related to cytoskeleton organisation, cell polarity, peptidyl-serine phosphorylation in parasites sorted from brown trout. In contrast, transcripts related to translation, ribonucleoprotein complex biogenesis and subunit organisation, non-membrane bounded organelle assembly, regulation of protein catabolic process and protein refolding were upregulated in rainbow trout-derived parasites. These findings show distinct molecular adaptations of parasites, which may underlie their distinct outcomes in the two hosts. Moreover, the identification of these differentially expressed transcripts may enable the identification of novel drug targets that may be exploited as treatment against T. bryosalmonae. We here also describe for the first time how FACS based isolation of T. bryosalmonae cells from infected kidney of fish fosters research and allows to define differentially expressed parasite transcripts in carrier and dead-end fish hosts.

Biosynthesis and characterization of cobalt nanoparticles using combination of different plants and their antimicrobial activity.

It has become crucial to biosynthesize efficient, secure, and affordable nanoparticles that we use for the treatment of various infections, including surgical site infection and wound infection, due to the rapid development of microbial resistance to numerous antibiotic drugs. The objective of the present study is to biosynthesize cobalt nanoparticles using an extract from the combined peels of garlic (Allium sativum) and onion (Allium cepa). Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction were used to confirm the synthesis of cobalt nanoparticle (XRD). Well diffusion was used to measure antimicrobial activity. Escherichia coli, Proteus, Staphylococcus aureus, Staphylococcus cohnii, and Klebsiella pneumonia were the bacterial strains employed Both the crude prepared extract and the biosynthesized cobalt nanoparticles demonstrated efficacy against all strains of bacteria, but the crude prepared extract displayed a low zone of inhibition ranging from 10 to 13 mm, while the biosynthesized cobalt nanoparticles displayed a high zone of inhibition ranging from 20 to 24 mm.

Description, molecular identification and pathological lesions of Huffmanela persica sp. nov. (Nematoda: Trichosomoididae: Huffmanelinae) from the daggertooth pike conger Muraenesox cinereus.

BACKGROUND: The genus Huffmanela Moravec, 1987 (Nematoda, Trichosomoididae, Huffmanelinae), represents a group of nematodes that infect both marine and freshwater fish, and the main gross feature of infection with different species of the genus is the presence of noticeable dark spots or tracks within the parasitized tissues. The purpose of this study was to describe morphologically and morphometrically the eggs of a new marine species of Huffmanela (Huffmanela persica sp. nov.), which was found in the form of black spots in the ovary and the tunica serosa of the stomach of the daggertooth pike conger (Muraenesox cinereus). The new species differs from Huffmanela hamo, another species reported from musculature of this host in Japan, in egg metrics, eggshell features and targeted organ. Molecular identification and pathological examination of the lesions caused by the new species are also reported. METHODS: Nematode eggs with varying degrees of development were separated from the infected tissues (ovary and tunica serosa of stomach) and investigated using light and scanning electron microscopy. Different species-specific markers (small subunit ribosomal DNA, 18S; large subunit ribosomal DNA, 28S; internal transcribed spacer, ITS) were used for molecular identification and phylogenetic study of the new species. Infected tissues were fixed in buffered formalin for pathological investigations. RESULTS: The fully developed eggs of H. persica sp. nov. are distinguished from those previously described from this host on the basis of their measurements (size, 54-68 × 31-43 µm; polar plugs, 6.4-9.7 × 8.4-12 µm; shell thickness, 3.5-6.1 µm) and a delicate but ornate uterine layer (UL) covering the entire eggshell including the polar plugs. Histopathological examination revealed a fibro-granulomatous inflammation in the ovary and the serosal layer of the stomach of infected fish. Maximum-likelihood (ML) phylogenetic analysis recovered a sister relationship between the new species of marine origin and Huffmanela species previously collected from freshwater hosts. CONCLUSIONS: The present study is the first to report the molecular characterization and phylogenetic position of a teleost-associated marine species of the genus Huffmanela. A comprehensive list of nominal and innominate populations of Huffmanela is also provided.

Identification of in vivo induced antigens of the malacosporean parasite Tetracapsuloides bryosalmonae (Cnidaria) using in vivo induced antigen technology.

Tetracapsuloides bryosalmonae is a malacosporean endoparasite that causes proliferative kidney disease (PKD) in wild and farmed salmonids in Europe and North America. The life cycle of T. bryosalmonae completes between invertebrate bryozoan and vertebrate fish hosts. Inside the fish, virulence factors of T. bryosalmonae are induced during infection or interactions with host cells. T. bryosalmonae genes expressed in vivo are likely to be important in fish pathogenesis. Herein, we identify in vivo induced antigens of T. bryosalmonae during infection in brown trout (Salmo trutta) using in vivo induced antigen technology (IVIAT). Brown trout were exposed to the spores of T. bryosalmonae and were sampled at different time points. The pooled sera were first pre-adsorbed with antigens to remove false positive results. Subsequently, adsorbed sera were used to screen a T. bryosalmonae cDNA phage expression library. Immunoscreening analysis revealed 136 immunogenic T. bryosalmonae proteins induced in brown trout during parasite development. They are involved in signal transduction, transport, metabolism, ion-protein binding, protein folding, and also include hypothetical proteins, of so far unknown functions. The identified in vivo induced antigens will be useful in the understanding of T. bryosalmonae pathogenesis during infection in susceptible hosts. Some of the antigens found may have significant implications for the discovery of candidate molecules for the development of potential therapies and preventive measures against T. bryosalmonae in salmonids.

Synergistic Effect of Conventional Medicinal Herbs against Different Pharmacological Activity.

Triticum aestivum (Family: Poaceae), Ocimum sanctum (Family: Lamiaceae), and Tinospora cordifolia (Family: Menispermaceae) are commonly known as wheatgrass, tulsi, and giloy, respectively, which are the plants used as medicines for the treatment of various diseases. All three medicinal plants possess phenolic compounds with other important chemical constituents such as polysaccharides, aliphatic compounds, and alkaloids. The extract of these plants has been prepared and investigated for antioxidant, total phenolic content, total flavonoid content, and antimicrobial study in order to discover potential sources for new pharmaceutical formulations. To determine the antioxidant activity, a free radical scavenging assay for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide was performed using ascorbic acid as the standard. The R 2 value of the prepared extract was found to be 0.9964 and 0.990 in DPPH and hydrogen peroxide scavenging activity, respectively. The phenolic and flavonoid content was found to be 87.50 µl/ml and 58.00 µl/ml, respectively. The diffusion method was used to screen the antimicrobial activity of the prepared extract sample against various microorganisms. This extract showed better results for antioxidant and antimicrobial activity.

Genome-wide alternative splicing profile in the posterior kidney of brown trout (Salmo trutta) during proliferative kidney disease.

BACKGROUND: The cnidarian myxozoan parasite Tetracapsuloides bryosalmonae causes chronic proliferative kidney disease (PKD) in salmonids. This parasite is a serious threat to wild and cultured salmonids. T. bryosalmonae undergoes intra-luminal sporogonic development in the kidney of brown trout (Salmo trutta) and the viable spores are released via urine. We investigated the alternative splicing pattern in the posterior kidney of brown trout during PKD. RESULTS: RNA-seq data were generated from the posterior kidney of brown trout collected at 12 weeks post-exposure to T. bryosalmonae. Subsequently, this data was mapped to the brown trout genome. About 153 significant differently expressed alternatively spliced (DEAS) genes, (delta PSI = 5%, FDR P-value < 0.05) were identified from 19,722 alternatively spliced events. Among the DEAS genes, the least and most abundant alternative splicing types were alternative 5' splice site (5.23%) and exon skipping (70.59%), respectively. The DEAS genes were significantly enriched for sodium-potassium transporter activity and ion homeostasis (ahcyl1, atp1a3a, atp1a1a.1, and atp1a1a.5). The protein-protein interaction network analysis enriched two local network clusters namely cation transporting ATPase C-terminus and Sodium/potassium ATPase beta chain cluster, and mixed inclusion of Ion homeostasis and EF-hand domain cluster. Furthermore, the human disease-related salmonella infection pathway was significantly enriched in the protein-protein interaction network. CONCLUSION: This study provides the first baseline information about alternative splicing in brown trout during PKD. The generated data lay a foundation for further functional molecular studies in PKD - brown trout infection model. The information generated from the present study can help to develop therapeutic strategies for PKD in the future.

New development and photocatalytic performance and antimicrobial activity of α-NH4(VO2)(HPO4) nanosheets.

α-NH4(VO2)(HPO4) nanosheets were developed by hydrothermal method. Furthermore, it's determined by the several analyses like XRD, Raman, FESEM, TEM, UV-Visible spectroscopy, TGA and DRS UV-Visible spectroscopy studies. The orthorhombic crystalline phase of α-NH4(VO2)(HPO4) nanosheets were recognized by XRD analysis. The α-NH4(VO2)(HPO4) nanosheets functional groups identification was investigated by Raman spectroscopy. Thermal gravimetric analysis of α-NH4(VO2)(HPO4) nanosheets were identified and its attain for three decomposition stages. The nanosheets of the α-NH4(VO2)(HPO4) was clearly evaluated by FESEM and TEM measurements. α-NH4(VO2)(HPO4) nanomaterial band gap energy was determined by DRS UV Visible spectroscopy analysis and the calculated bandgap energy is 1.83 eV. Hence, it was more convenient way for the dye degradation applications. These α-NH4(VO2)(HPO4) nanosheets was will be tested in the photocatalytic and antimicrobial applications. In this case, antimicrobial study was not encouraged in the catalyst. Consequently, this material has more encouraging for electrostatic interaction with enhanced for the applications.

Morphological and Molecular Characterization of a New Myxozoan, Myxobolus grassi sp. nov. (Myxosporea), Infecting the Grass Carp, Ctenopharyngodon idella in the Gomti River, India.

Myxosporeans are well-known parasites infecting food fishes in fresh and marine water around the globe. Grass carp (Ctenopharyngodon idella), a freshwater food fish commonly cultured in India with has significant economic importance. Herein, the study focuses on the description of a new myxosporean species, Myxobolus grassi sp. nov. from the gills as primary site and liver as secondary site of infection in grass carp. Both organs (gill and liver) were infected concurrently in the host and the prevalence of grass carp infection was 4.05% in gill filaments and liver, respectively. Identification of species was based on the morphological and morphometric features of the myxospore as well as 18S rDNA sequence data. A smear from gill and liver exhibited hundreds of morphologically similar myxospores. BLAST search revealed 98% sequence similarity and 0.03 genetic distance with M. catlae (KM029967) infecting gill lamellae of mrigal carp (Cirrhinus cirrhosus) from India and 98-84% sequence similarity with other myxobolids in India, China, Japan, Malaysia, Turkey and Hungary. Phylogenetically, it clustered with other myxobolids infecting gills and related organs (i.e., vital organ) of Indian cyprinid carp species. On the basis of myxospore morphology and 18S sequence, we propose M. grassi sp. nov.

Haloperidol alters the behavioral, hematological and biochemical parameters of freshwater African catfish, Clarias gariepinus (Burchell 1822).

The presence of drugs and their metabolites in surface waters and municipal effluents has been reported in several studies, but their impacts on aquatic organisms are not yet well studied. The present study investigated the effects of exposure to the antipsychotic drug, haloperidol on the behavioral, hematological and biochemical parameters in juvenile Clarias gariepinus. The fishes were exposed to 0.12, 0.24 and 0.48 mg/L haloperidol for 15 days and later withdrawn from the toxicant and allowed to recover for 5 days. Blood was sampled on days 1, 5, 10, 15, and after the 5-day recovery for hematological and biochemical analysis. The pack cell volume (PCV), red blood cells (RBC), hemoglobin (Hb), reticulocytes and lymphocyte counts were significantly reduced in the exposed fish. The neutrophil counts were increased while that of monocytes, basophils and eosinophils were not affected by the drug. The mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were not different from the control on exposure to the drug. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and acid phosphatase (ACP); and serum creatinine, bile acid and bilirubin were increased on 15-day exposure to the drug. The activity of the clotting factor fibrinogen was reduced compared to the control after exposure to the drug. Haloperidol at concentrations used on 15-day exposure were toxic to fish, but the effect appeared short-lived, as it dissipated on 5-day withdrawal from the drug. While further studies are needed to ascertain the impact of prolonged exposure to environmentally relevant concentrations, caution is advised to avoid eco-toxicological damage to aquatic organisms.

Global popularization of CuNiO2 and their rGO nanocomposite loveabled to the photocatalytic properties of methylene blue.

New advancements of photocatalytic activity with higher efficiency, low price are most important, which is challenging in industrialized and many fields. We have introduced CuNiO2 and CuNiO2/rGO nanocomposite was generally prepared by the hydrothermal treatment and tested to the photocatalytic studies. Photocatalytic measurements of CuNiO2 with different weight percentages CuNiO2/rGO (25/75), (50/50), and (75/25) are achieved to the efficiency under visible light, in this case, CuNiO2/rGO (50/50) composite have the highest performance is scrutinized. This was obeyed for a synergistic effect between CuNiO2 nanoparticles and rGO composites. Furthermore, the CuNiO2, CuNiO2/rGO (25/75), (50/50), and (75/25) nanocomposite were tested by several analyses like XRD, FT-IR, DRS UV Visible spectroscopy, Raman spectroscopy, and FESEM & HRTEM investigations. In this regard all measurements are very clear and satisfied; therefore we are encouraged for future developing environmental applications.

Kinetics of Parasite-Specific Antibody and B-Cell-Associated Gene Expression in Brown Trout, Salmo trutta during Proliferative Kidney Disease.

Tetracapsuloides bryosalmonae, a myxozoan endoparasite often causes chronic infection in brown trout. Antiparasite immunity mediated by antibodies and B cells is known as an important determinant of host survival and parasite proliferation during chronic infections. Accordingly, studying their time course during proliferative kidney disease (PKD) might be helpful in improving our understanding of its chronic nature. Therefore, we conducted this study to examine parasite specific serum antibody and B-cell-mediated response in laboratory-infected brown trout at different time points. Brown trout were exposed to the spores of T. bryosalmonae, derived from infected bryozoans. Samples were collected at different time points and processed for indirect ELISA, histopathology, and qRT-PCR. T. bryosalmonae specific antibody was detected at 4 weeks post exposure (wpe) and it persisted until 17 wpe. Additionally, the expressions of C4A, CD34, CD79A, BLNK, CD74, BCL7, and CD22 were differentially regulated in the important immune organs, kidney and spleen. To our knowledge, this is the first study addressing anti-T. bryosalmonae antibody response in brown trout at different time points. The results from this study provide valuable insights into the processes leading to changes in B cell development, inflammation and antibody production during the course of PKD in brown trout.

Co-Infection of Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) in the Wild Crustaceans of Andaman and Nicobar Archipelago, India.

The present study was intended to screen the wild crustaceans for co-infection with Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) and White Spot Syndrome Virus (WSSV) in Andaman and Nicobar Archipelago, India. We screened a total of 607 shrimp and 110 crab samples using a specific polymerase chain reaction, and out of them, 82 shrimps (13.5%) and 5 (4.5%) crabs were found positive for co-infection of IHHNV and WSSV. A higher rate of co-infection was observed in Penaeus monodon and Scylla serrata than other shrimp and crab species. The nucleotide sequences of IHHNV and WSSV obtained from crab in this present study exhibited very high sequence identity with their counterparts retrieved from various countries. Histopathological analysis of the infected shrimp gill sections further confirmed the eosinophilic intra-nuclear cowdry type A inclusion bodies and basophilic intra-nuclear inclusion bodies characteristics of IHHNV and WSSV infections, respectively. The present study serves as the first report on co-infection of WSSV and IHHNV in Andaman and Nicobar Archipelago, India and accentuates the critical need for continuous monitoring of wild crustaceans and appropriate biosecurity measures for brackishwater aquaculture.

Development of Fish Parasite Vaccines in the OMICs Era: Progress and Opportunities.

Globally, parasites are increasingly being recognized as catastrophic agents in both aquaculture sector and in the wild aquatic habitats leading to an estimated annual loss between 1.05 billion and 9.58 billion USD. The currently available therapeutic and control measures are accompanied by many limitations. Hence, vaccines are recommended as the "only green and effective solution" to address these concerns and protect fish from pathogens. However, vaccine development warrants a better understanding of host-parasite interaction and parasite biology. Currently, only one commercial parasite vaccine is available against the ectoparasite sea lice. Additionally, only a few trials have reported potential vaccine candidates against endoparasites. Transcriptome, genome, and proteomic data at present are available only for a limited number of aquatic parasites. Omics-based interventions can be significant in the identification of suitable vaccine candidates, finally leading to the development of multivalent vaccines for significant protection against parasitic infections in fish. The present review highlights the progress in the immunobiology of pathogenic parasites and the prospects of vaccine development. Finally, an approach for developing a multivalent vaccine for parasitic diseases is presented. Data sources to prepare this review included Pubmed, google scholar, official reports, and websites.

Data of de novo transcriptome assembly of the myxozoan parasite Tetracapsuloides bryosalmonae.

Tetracapsuloides bryosalmonae, a myxozoan endoparasite, causes proliferative kidney disease in salmonids. The life cycle of T. bryosalmonae occurs between invertebrate bryozoan and vertebrate fish hosts. T. bryosalmonae develops in the body cavity of colonial bryozoan and spores are released from mature spore sacs into the water likely through the vestibular pore and infect fish by attaching to their gills. However, very little is known about the transcriptome of this important parasite, which hampers studies into the molecular mechanisms of host-parasite interactions and understanding the parasite biology. In order to circumvent this limitation, we performed de novo transcriptome assembly on the sacs of T. bryosalmonae, collected from infected bryozoan Fredericella sultana. A total of 111.5 million filtered paired-end reads was obtained and assembled into 25,908 contigs corresponding to putative transcripts that were functionally annotated. More than 50% of the assembled transcripts (13,071 contigs) had a significant hit in NCBI non-redundant database. Based on Gene ontology annotation, the most highly scored categories of molecular function of the contigs were related to binding and catalytic activities in T. bryosalmonae. This study provides a global overview of the T. bryosalmonae transcriptome that will be a valuable resource for identifying virulence factors, gene discovery, genome annotation, and vaccine development applications. This data is accessible via NCBI BioProject (PRJNA680464).

Transcriptome Analysis Elucidates the Key Responses of Bryozoan Fredericella sultana during the Development of Tetracapsuloides bryosalmonae (Myxozoa).

Bryozoans are sessile, filter-feeding, and colony-building invertebrate organisms. Fredericella sultana is a well known primary host of the myxozoan parasite Tetracapsuloides bryosalmonae. There have been no attempts to identify the cellular responses induced in F. sultana during the T. bryosalmonae development. We therefore performed transcriptome analysis with the aim of identifying candidate genes and biological pathways of F. sultana involved in the response to T. bryosalmonae. A total of 1166 differentially up- and downregulated genes were identified in the infected F. sultana. Gene ontology of biological processes of upregulated genes pointed to the involvement of the innate immune response, establishment of protein localization, and ribosome biogenesis, while the downregulated genes were involved in mitotic spindle assembly, viral entry into the host cell, and response to nitric oxide. Eukaryotic Initiation Factor 2 signaling was identified as a top canonical pathway and MYCN as a top upstream regulator in the differentially expressed genes. Our study provides the first transcriptional profiling data on the F. sultana zooid's response to T. bryosalmonae. Pathways and upstream regulators help us to understand the complex interplay in the infected F. sultana. The results will facilitate the elucidation of innate immune mechanisms of bryozoan and will lay a foundation for further analyses on bryozoan-responsive candidate genes, which will be an important resource for the comparative analysis of gene expression in bryozoans.

First transcriptome analysis of bryozoan Fredericella sultana, the primary host of myxozoan parasite Tetracapsuloides bryosalmonae.

Bryozoans are aquatic invertebrate moss animals that are found worldwide. Fredericella sultana is a freshwater bryozoan and is the most common primary host of myxozoan parasite, Tetracapsuloides bryosalmonae. However, limited genomic resources are available for this bryozoan, which hampers investigations into the molecular mechanisms of host-parasite interactions. To better understand these interactions, there is a need to build a transcriptome dataset of F. sultana, for functional genomics analysis by large-scale RNA sequencing. Total RNA was extracted from zooids of F. sultana cultivated under controlled laboratory conditions. cDNA libraries were prepared and were analyzed by the Illumina paired-ends sequencing. The sequencing data were used for de novo transcriptome assembly and functional annotation. Approximately 118 million clean reads were obtained, and assembled into 85,544 contigs with an average length of 852 bp, an N50 of 1,085 bp, and an average GC content 51.4%. A total of 23,978 (28%) contigs were annotated using BLASTX analysis. Of these transcripts, 4,400 contigs had highest similarity to brachiopod species Lingula anatina. Based on Gene ontology (GO) annotation, the most highly scored categories of biological process were categorized into cellular process (27%), metabolic process (24%), and biological regulation (8%) in the transcriptome of F. sultana. This study gives first insights into the transcriptome of F. sultana and provides comprehensive genetic resources for the species. We believe that the transcriptome of F. sultana will serve as a useful genomic dataset to accelerate research of functional genomics and will help facilitate whole genome sequencing and annotation. Candidate genes potentially involved in growth, proteolysis, and stress/immunity-response were identified, and are worthy of further investigation.

Identification and Expression Profiling of Toll-Like Receptors of Brown Trout (Salmo trutta) during Proliferative Kidney Disease.

Proliferative kidney disease is an emerging disease among salmonids in Europe and North America caused by the myxozoan parasite Tetracapsuloides bryosalmonae. The decline of endemic brown trout (Salmo trutta) in the Alpine streams of Europe is fostered by T. bryosalmonae infection. Toll-like receptors (TLRs) are a family of pattern recognition receptors that acts as sentinels of the immune system against the invading pathogens. However, little is known about the TLRs' response in salmonids against the myxozoan infection. In the present study, we identified and evaluated TLR1, TLR19, and TLR13-like genes of brown trout using data-mining and phylogenetic analysis. The expression pattern of TLRs was examined in the posterior kidney of brown trout infected with T. bryosalmonae at various time points. Typical Toll/interleukin-1 receptor protein domain was found in all tested TLRs. However, TLR13-like chr2 had a short amino acid sequence with no LRR domain. Phylogenetic analysis illustrated that TLR orthologs are conserved across vertebrates. Similarly, a conserved synteny gene block arrangement was observed in the case of TLR1 and TLR19 across fish species. Interestingly, all tested TLRs showed their maximal relative expression from 6 to 10 weeks post-exposure to the parasite. Our results suggest that these TLRs may play an important role in the innate defense mechanism of brown trout against the invading T. bryosalmonae.

The Malacosporean Myxozoan Parasite Tetracapsuloides bryosalmonae: A Threat to Wild Salmonids.

Tetracapsuloides bryosalmonae is a myxozoan parasite responsible for proliferative kidney disease (PKD) in a wide range of salmonids. PKD, characterized by high mortality and morbidity, is well known for affecting aquaculture operations and wild salmonid populations across Europe and North America. The life cycle of T. bryosalmonae revolves around freshwater bryozoan and salmonid fish hosts. In recent years, T. bryosalmonae has been reported among wild salmonids from the European countries where it has not been reported previously. T. bryosalmonae is believed to be a possible reason for the diminishing wild salmonid populations in the natural water bodies of many European countries. Climate crisis driven rising water temperature can further accelerate the distribution of T. bryosalmonae. Expansion of the geographical distribution of T. bryosalmonae may further advocate the decline of wild salmonid populations, especially brown trout (Salmo trutta) in their habitats. Mathematical models are used to understand the pattern and distribution of T. bryosalmonae among the host in the natural water bodies. The present manuscript not only summarizes the incidences of T. bryosalmonae among the wild salmonid populations, but also discusses the contemporary understanding about the development of T. bryosalmonae in its hosts and the influences of various factors in the spread of the disease in the wild.

Transcriptome profiling of posterior kidney of brown trout, Salmo trutta, during proliferative kidney disease.

BACKGROUND: Tetracapsuloides bryosalmonae is a myxozoan parasite which causes economically important and emerging proliferative kidney disease (PKD) in salmonids. Brown trout, Salmo trutta is a native fish species of Europe, which acts as asymptomatic carriers for T. bryosalmonae. There is only limited information on the molecular mechanism involved in the kidney of brown trout during T. bryosalmonae development. We employed RNA sequencing (RNA-seq) to investigate the global transcriptome changes in the posterior kidney of brown trout during T. bryosalmonae development. METHODS: Brown trout were exposed to the spores of T. bryosalmonae and posterior kidneys were collected from both exposed and unexposed control fish. cDNA libraries were prepared from the posterior kidney and sequenced. Bioinformatics analysis was performed using standard pipeline of quality control, reference mapping, differential expression analysis, gene ontology, and pathway analysis. Quantitative real time PCR was performed to validate the transcriptional regulation of differentially expressed genes, and their correlation with RNA-seq data was statistically analyzed. RESULTS: Transcriptome analysis identified 1169 differentially expressed genes in the posterior kidney of brown trout, out of which 864 genes (74%) were upregulated and 305 genes (26%) were downregulated. The upregulated genes were associated with the regulation of immune system process, vesicle-mediated transport, leucocyte activation, and transport, whereas the downregulated genes were associated with endopeptidase regulatory activity, phosphatidylcholine biosynthetic process, connective tissue development, and collagen catabolic process. CONCLUSION: To our knowledge, this is the first RNA-seq based transcriptome study performed in the posterior kidney of brown trout during active T. bryosalmonae development. Most of the upregulated genes were associated with the immune system process, whereas the downregulated genes were associated with other metabolic functions. The findings of this study provide insights on the immune responses mounted by the brown trout on the developing parasite, and the host molecular machineries modulated by the parasite for its successful multiplication and release.