Flounder
Flatfishes
Antifreeze Proteins
Fish Diseases
Fishes
Myxozoa
Antifreeze Proteins, Type I
RNA Virus Infections
Aquaculture
Oligohymenophorea
Metolazone
Novirhabdovirus
Gills
Isolation of plaice (Pleuronectes platessa) alpha1-microglobulin: conservation of structure and chromophore. (1/289)
A cDNA coding for plaice (Pleuronectes platessa) alpha1-microglobulin (Leaver et al., 1994, Comp. Biochem. Physiol. 108B, 275-281) was expressed and purified from baculovirus-infected insect cells. Specific monoclonal antibodies were then prepared and used to isolate the protein from plaice liver and serum. Mature 28.5 kDa alpha1-microglobulin was found in both liver and serum. The protein consisted of an 184 amino acid peptide with a complex N-glycan in position Asn123, one intrachain disulfide bridge and a yellow-brown chromophore. Physicochemical characterization indicated a globular shape with a frictional ratio of 1.37, electrophoretic charge-heterogeneity and antiparallel beta-sheet structure. A smaller, incompletely glycosylated, yellow-brown alpha1-microglobulin as well as a 45 kDa precursor protein were also found in liver. The chromophore was found to be linked to alpha1-microglobulin intracellularly. Recombinant plaice alpha1-microglobulin isolated from insect cells had the same N-terminal sequence, globular shape and yellow-brown color as mature alpha1-microglobulin, but carried a smaller, fucosylated, non-sialylated N-glycan in the Asn123 position. The concentration of alpha1-microglobulin in plaice serum was 20 mg/l and it was found both as a 28.5 kDa component and as high molecular weight components. Thus, the size, shape, charge and color of plaice alpha1-microglobulin were similar to mammalian alpha1-microglobulin, indicating a high degree of structural conservation between fish and human alpha1-microglobulin. The monoclonal antibodies against plaice alpha1-microglobulin cross-reacted with human alpha1-microglobulin, emphasizing the structural similarity. (+info)Recent and rapid amplification of the sperm basic nuclear protein genes in winter flounder. (2/289)
The high molecular weight basic nuclear proteins (HMrBNPs), which are tightly bound to sperm chromatin in winter flounder, are made up of imperfect reiterations of simple peptide sequences that contain phosphorylatable DNA-binding motifs. Genomic Southern blots hybridized with probes to the coding and non-coding regions of HMrBNP mRNA showed that HMrBNP sequences form a complex multi-gene family. Previously, one gene (2B) was used to establish an evolutionary link between histone H1 and the HMrBNPs. Further examination of this complex, multi-gene family has now revealed that the majority of the HMrBNP genes are linked as 4.5 kb direct tandem repeats that each contain a 2.8 kb coding region and a 1.7 kb intergenic region (IR). These findings, combined with the cloning of the IR, established that the tandemly repeated genes lack introns and code for the abundant 3 kb HMrBNP mRNAs that produce the prominent 110 kDa HMrBNP. Southern blotting of DNAs from other righteye flounder species showed that HMrBNP multi-gene families were present in closely related species, though with substantial differences in restriction patterns and band intensities, but were not detected in more distantly related flounders. These observations are consistent with recent and rapid elaboration of the HMrBNP gene family. (+info)Stoichiometry and Na+ binding cooperativity of rat and flounder renal type II Na+-Pi cotransporters. (3/289)
The stoichiometry of the rat and flounder isoforms of the renal type II sodium-phosphate (Na+-Pi) cotransporter was determined directly by simultaneous measurements of phosphate (Pi)-induced inward current and uptake of radiolabeled Pi and Na+ in Xenopus laevis oocytes expressing the cotransporters. There was a direct correlation between the Pi-induced inward charge and Pi uptake into the oocytes; the slope indicated that one net inward charge was transported per Pi. There was also a direct correlation between the Pi-induced inward charge and Na+ influx; the slope indicated that the influx of three Na+ ions resulted in one net inward charge. This behavior was similar for both isoforms. We conclude that for both Na+-Pi cotransporter isoforms the Na+:Pi stoichiometry is 3:1 and that divalent Pi is the transported substrate. Steady-state activation of the currents showed that the Hill coefficients for Pi were unity for both isoforms, whereas for Na+, they were 1.8 (flounder) and 2.5 (rat). Therefore, despite significant differences in the apparent Na+ binding cooperativity, the estimated Na+:Pi stoichiometry was the same for both isoforms. (+info)Protein kinase C activators induce membrane retrieval of type II Na+-phosphate cotransporters expressed in Xenopus oocytes. (4/289)
1. The rate of inorganic phosphate (Pi) reabsorption in the mammalian kidney is determined by the amount of type II sodium-coupled inorganic phosphate (Na+-Pi) cotransport protein present in the brush border membrane. Under physiological conditions, parathyroid hormone (PTH) leads to an inhibition of Na+-Pi cotransport activity, most probably mediated by the protein kinase A (PKA) and/or C (PKC) pathways. 2. In this study, PKC-induced inhibition of type II Na+-Pi cotransport activity was characterized in Xenopus laevis oocytes using electrophysiological and immunodetection techniques. Transport function was quantified in terms of Pi-activated current. 3. Oocytes expressing the type IIa rat renal, type IIb flounder renal or type IIb mouse intestinal Na+-Pi cotransporters lost > 50 % of Pi-activated transport function when exposed to the PKC activators DOG (1,2-dioctanoyl-sn-glycerol) or PMA (phorbol 12-myristate 13-acetate). DOG-induced inhibition was partially reduced with the PKC inhibitors staurosporine and bisindolylmaleimide I. Oocytes exposed to the inactive phorbol ester 4alpha-PDD (4alpha-phorbol 12,13-didecanoate) showed no significant loss of cotransporter function. 4. Oocytes expressing the rat renal Na+-SO42- cotransporter alone, or coexpressing this with the type IIa rat renal Na+-Pi cotransporter, showed no downregulation of SO42--activated cotransport activity by DOG. 5. Steady-state and presteady-state voltage-dependent kinetics of type II Na+-Pi cotransporter function were unaffected by DOG. 6. DOG induced a decrease in membrane capacitance which indicated a reduction in membrane area, thereby providing evidence for PKC-mediated endocytosis. 7. Immunocytochemical studies showed a redistribution of type II Na+-Pi cotransporters from the oolemma to the submembrane region after DOG treatment. Surface biotinylation confirmed a DOG-induced internalization of the transport protein. 8. These findings document a specific retrieval of exogenous type II Na+-Pi cotransporters induced by activation of a PKC pathway in the Xenopus oocyte. (+info)Structure and expression of the highly repetitive histone H1-related sperm chromatin proteins from winter flounder. (5/289)
In the late stages of spermatogenesis, winter flounder produce a family of high molecular mass (80-200 kDa) basic nuclear proteins (HMrBNPs) that combine with the normal complement of histones to produce condensed sperm chromatin with an increased nucleosomal repeat length. The HMrBNPs have a biased amino-acid composition in which Arg, Ser, Lys and Pro are abundant because of their presence in many simple peptide repeats. The organization of these repeats was deduced by cDNA cloning. The predominant repeating units are related 26- and 30-amino-acid sequences that in turn are linked by 6-amino-acid spacers to form 58- and 62-amino-acid repeats. Subsets of these repeats are also present, such as a dispersed 20-amino-acid repeat and a tandem array of nine heptapeptides at the C-terminus. The HMrBNPs appear to have evolved from an extreme H1 variant that has an N-terminal tail of HMrBNP-like sequence linked to an H1 globular region. Based on sequences of the most abundant HMrBNP cDNAs, and the lack of hybridization between HMrBNP mRNAs and a DNA probe for the H1 globular region, the latter domain appears to have been lost during expansion and amplification of the HMrBNP-like repeats. Transcripts of the HMrBNP and H1 variant genes are present in testis RNAs only during the mid-spermatid stage of spermatogenesis, at the same time that HMrBNPs in their highly phosphorylated form first appear in the nucleus. Judging by the lack of a lag between HMrBNP mRNA synthesis and translation, the mRNAs for these highly basic proteins are not stored for any length of time. Instead, the deposition of HMrBNPs onto DNA, which coincides with the major reorganization and silencing of the chromatin, may be controlled by dephosphorylation. (+info)NO2- uptake and HCO3- excretion in the intestine of the European flounder (Platichthys flesus). (6/289)
Ion transport across isolated intestinal segments from the European flounder (Platichthys flesus) was studied with the primary aim of evaluating the mechanisms of nitrite (NO2-) uptake and HCO3- excretion. A double-radiolabelling technique was applied to monitor unidirectional Cl- and Na+ influx. Furthermore, net fluxes of NO2-, HCO3-, Cl-, Na+ and water were recorded. NO2- uptake was inhibited by mucosal application of bumetanide (10(-)4 mol l-1) but not DIDS (10(-)3 mol l-1), suggesting that NO2- is transported across the intestine via the Na+/K+/2Cl- cotransporter rather than via a Cl-/HCO3- exchanger. In addition to transport via the Na+/K+/2Cl- cotransporter, NO2- uptake may also occur through the Na+/Cl- cotransporter and by conductive transport. NO2- and Cl- influx rates seemed to reflect their mucosal concentrations, and NO2- did not influence unidirectional influx or net flux of Cl-. HCO3- efflux was significantly reduced in the presence of 10(-)3 mol l-1 DIDS in the mucosal solution. This may indicate the presence of an apical Cl-/HCO3- exchanger in the intestinal epithelium, which would not comply with the current model of HCO3- excretion in the intestine of marine teleost fish. An alternative model of HCO3- excretion across the intestinal epithelium is proposed. (+info)Expression cloning and characterization of a novel sodium-dicarboxylate cotransporter from winter flounder kidney. (7/289)
A cDNA coding for a Na+-dicarboxylate cotransporter, fNaDC-3, from winter flounder (Pseudopleuronectes americanus) kidney was isolated by functional expression in Xenopus laevis oocytes. The fNaDC-3 cDNA is 2384 nucleotides long and encodes a protein of 601 amino acids with a calculated molecular mass of 66.4 kDa. Secondary structure analysis predicts at least eight membrane-spanning domains. Transport of succinate by fNaDC-3 was sodium-dependent, could be inhibited by lithium, and evoked an inward current. The apparent affinity constant (Km) of fNaDC-3 for succinate of 30 microM resembles that of Na+-dicarboxylate transport in the basolateral membrane of mammalian renal proximal tubules. The substrates specific for the basolateral transporter, 2,3-dimethylsuccinate and cis-aconitate, not only inhibited succinate uptake but also evoked inward currents, proving that they are transported by fNaDC-3. Succinate transport via fNaDC-3 decreased by lowering pH, as did citrate transport, although much more moderately. These characteristics suggest that fNaDC-3 is a new type of Na+-dicarboxylate transporter that most likely corresponds to the Na+-dicarboxylate cotransporter in the basolateral membrane of mammalian renal proximal tubules. (+info)Studies of a putative ice-binding motif in winter flounder skin-type anti-freeze polypeptide. (8/289)
Winter flounder contains two distinct anti-freeze protein isoforms, which are the liver-type extracellular anti-freeze proteins and the skin-type intracellular anti-freeze protein. The skin-type anti-freeze proteins exhibit lower anti-freeze activities than the liver-type isoforms and this might be due to their lacking complete ice-binding motifs. One of the skin-type anti-freeze proteins, skin-type anti-freeze protein-3, does contain putative overlapping ice-binding motifs with the sequences '-K-DT-' and '-DT-K-'. Synthetic anti-freezes containing 0-3 repeats of the '-DT-K-' motif were tested for stability and activity. Loss of the single '-DT-K-' of skin-type anti-freeze protein-3 increases the anti-freeze activity and increasing the number of motifs to two or three lowers the activity. The decrease in activity with an increasing frequency of the motif correlates with a decrease in the helical content of these peptides at 0 degrees C. (+info)I'm sorry for any confusion, but "flounder" is not a medical term. It is a common name used for several species of flatfish that are widely consumed as food. If you have any questions about medical terminology or health-related topics, please don't hesitate to ask!
Flatfishes are a group of marine fish characterized by having both eyes on one side of their head, which is flattened laterally. This gives them a distinctive asymmetrical appearance. They belong to the order Pleuronectiformes and include various species such as halibut, flounder, sole, and plaice. Flatfishes start their life with eyes on both sides of their head, but during development, one eye migrates to the other side of the head, a process known as metamorphosis. They are bottom-dwelling predators that rely on their excellent camouflage abilities to ambush prey.
Antifreeze proteins (AFPs) are a group of small proteins that bind to ice crystals and inhibit their growth at temperatures above the freezing point of water. They are produced by various cold-tolerant organisms, including fish, insects, and plants, as a survival adaptation to subzero environments. AFPs function by adsorbing to the surface of nascent ice crystals and lowering the freezing point of the solution in a noncolligative manner, meaning that their effect is not simply due to the dilution of solutes. This ability allows these organisms to survive in freezing conditions without the formation of damaging ice inside their cells.
In medical contexts, AFPs have been studied for their potential therapeutic applications, particularly in cryopreservation and tissue engineering. They could help protect organs, tissues, and cells from freeze damage during storage and transportation, expanding the possibilities for transplantation and regenerative medicine. Additionally, AFPs may have a role in treating hypothermia and frostbite by preventing or minimizing ice crystal formation in injured tissues. However, more research is needed to fully understand their mechanisms and optimize their use in clinical settings.
"Fish diseases" is a broad term that refers to various health conditions and infections affecting fish populations in aquaculture, ornamental fish tanks, or wild aquatic environments. These diseases can be caused by bacteria, viruses, fungi, parasites, or environmental factors such as water quality, temperature, and stress.
Some common examples of fish diseases include:
1. Bacterial diseases: Examples include furunculosis (caused by Aeromonas salmonicida), columnaris disease (caused by Flavobacterium columnare), and enteric septicemia of catfish (caused by Edwardsiella ictaluri).
2. Viral diseases: Examples include infectious pancreatic necrosis virus (IPNV) in salmonids, viral hemorrhagic septicemia virus (VHSV), and koi herpesvirus (KHV).
3. Fungal diseases: Examples include saprolegniasis (caused by Saprolegnia spp.) and cotton wool disease (caused by Aphanomyces spp.).
4. Parasitic diseases: Examples include ichthyophthirius multifiliis (Ich), costia, trichodina, and various worm infestations such as anchor worms (Lernaea spp.) and tapeworms (Diphyllobothrium spp.).
5. Environmental diseases: These are caused by poor water quality, temperature stress, or other environmental factors that weaken the fish's immune system and make them more susceptible to infections. Examples include osmoregulatory disorders, ammonia toxicity, and low dissolved oxygen levels.
It is essential to diagnose and treat fish diseases promptly to prevent their spread among fish populations and maintain healthy aquatic ecosystems. Preventative measures such as proper sanitation, water quality management, biosecurity practices, and vaccination can help reduce the risk of fish diseases in both farmed and ornamental fish settings.
Ciliophora is a group of protozoan organisms that are characterized by the presence of hair-like structures called cilia. Some species of Ciliophora can cause infections in humans, known as ciliophoriasis or ciliate infections. These infections typically occur in individuals with weakened immune systems, such as those with HIV/AIDS, cancer, or who are taking immunosuppressive drugs.
The most common way that Ciliophora infect humans is through the ingestion of contaminated food or water. Once inside the body, the ciliates can cause a range of symptoms depending on the species and the location of the infection. For example, infections in the gastrointestinal tract can cause abdominal pain, diarrhea, and vomiting, while lung infections can lead to coughing, wheezing, and difficulty breathing.
Treatment for Ciliophora infections typically involves the use of antiprotozoal medications, such as metronidazole or tinidazole. In severe cases, hospitalization may be necessary to manage symptoms and prevent complications. Preventing ciliophoriasis involves practicing good hygiene, avoiding contaminated food and water, and taking steps to boost the immune system in individuals who are at high risk of infection.
"Fish proteins" are not a recognized medical term or concept. However, fish is a source of protein that is often consumed in the human diet and has been studied in various medical and nutritional contexts. According to the USDA FoodData Central database, a 100-gram serving of cooked Atlantic salmon contains approximately 25 grams of protein.
Proteins from fish, like other animal proteins, are complete proteins, meaning they contain all nine essential amino acids that cannot be synthesized by the human body and must be obtained through the diet. Fish proteins have been studied for their potential health benefits, including their role in muscle growth and repair, immune function, and cardiovascular health.
It's worth noting that some people may have allergies to fish or seafood, which can cause a range of symptoms from mild skin irritation to severe anaphylaxis. If you suspect you have a fish allergy, it's important to consult with a healthcare professional for proper diagnosis and management.
I believe there may be a misunderstanding in your question. The term "fishes" is not typically used in a medical context. "Fish" or "fishes" refers to any aquatic organism belonging to the taxonomic class Actinopterygii (bony fish), Chondrichthyes (sharks and rays), or Agnatha (jawless fish).
However, if you are referring to a condition related to fish or consuming fish, there is a medical issue called scombroid fish poisoning. It's a foodborne illness caused by eating spoiled or improperly stored fish from the Scombridae family, which includes tuna, mackerel, and bonito, among others. The bacteria present in these fish can produce histamine, which can cause symptoms like skin flushing, headache, diarrhea, and itchy rash. But again, this is not related to the term "fishes" itself but rather a condition associated with consuming certain types of fish.
Myxozoa is a group of microscopic, primarily freshwater, parasitic cnidarians. They have complex life cycles involving one or more intermediate hosts, such as annelids or mollusks, and a definitive host, usually a fish. The adult stage of the parasite develops in the tissues of the definitive host, while the larval stages infect the muscles, gills, or other organs of the intermediate hosts.
Myxozoans are characterized by their small size (usually less than 1 mm), simple body structure, and unique spore stage. The spores contain one or two polar capsules, which are coiled structures that release thread-like filaments to help the spores attach to host tissues.
Myxozoans can cause significant damage to their hosts, leading to diseases such as whirling disease in fish and proliferative kidney disease in salmonids. These parasites have a wide geographic distribution and are found in both wild and farmed aquatic animals.
Antifreeze proteins (AFPs), type I are a group of small, structurally similar polypeptides found in certain cold-tolerant organisms, such as fish, insects, and plants. These proteins function to prevent the formation of ice crystals within the organism's body fluids, thereby preventing freezing at subzero temperatures.
Type I AFPs are typically unstructured in solution but adopt an alpha-helical structure upon binding to ice. They have a molecular weight ranging from 3 to 6 kilodaltons and consist of a single, highly conserved domain with a characteristic repeat motif. The primary sequence of type I AFPs contains multiple repeats of a consensus motif, Thr-Ala-Ala (TAA), which is essential for their ice-binding activity.
Type I AFPs bind to the prism face of ice and inhibit further growth of the crystal, thereby preventing the formation of larger ice crystals that could damage tissues. These proteins have been extensively studied for their potential applications in cryopreservation, food technology, and biomedical engineering.
RNA virus infections refer to diseases or conditions caused by the invasion and replication of RNA (Ribonucleic acid) viruses in host cells. These viruses use RNA as their genetic material, which is different from DNA (Deoxyribonucleic acid) viruses. Upon entering a host cell, the RNA virus releases its genetic material, which then uses the host cell's machinery to produce new viral components and replicate. This process can lead to various outcomes, depending on the specific virus and the host's immune response:
1. Asymptomatic infection: Some RNA virus infections may not cause any noticeable symptoms and may only be discovered through diagnostic testing.
2. Acute infection: Many RNA viruses cause acute infections, characterized by the rapid onset of symptoms that typically last for a short period (days to weeks). Examples include the common cold (caused by rhinoviruses), influenza (caused by orthomyxoviruses), and some gastrointestinal infections (caused by noroviruses or rotaviruses).
3. Chronic infection: A few RNA viruses can establish chronic infections, where the virus persists in the host for an extended period, sometimes leading to long-term health complications. Examples include HIV (Human Immunodeficiency Virus), HCV (Hepatitis C Virus), and HTLV-1 (Human T-lymphotropic virus type 1).
4. Latent infection: Some RNA viruses, like herpesviruses, can establish latency in the host, where they remain dormant for extended periods but can reactivate under certain conditions, causing recurrent symptoms or diseases.
5. Oncogenic potential: Certain RNA viruses have oncogenic properties and can contribute to the development of cancer. For example, retroviruses like HTLV-1 can cause leukemia and lymphoma by integrating their genetic material into the host cell's DNA and altering gene expression.
Treatment for RNA virus infections varies depending on the specific virus and the severity of the infection. Antiviral medications, immunotherapy, and supportive care are common treatment strategies. Vaccines are also available to prevent some RNA virus infections, such as measles, mumps, rubella, influenza, and hepatitis A and B.
"Ice" is a slang term that is commonly used to refer to crystal methamphetamine, which is a powerful and highly addictive stimulant drug. It gets its name from its crystalline appearance. Medically, methamphetamine is used in the treatment of attention deficit hyperactivity disorder (ADHD) and obesity, but only under strict medical supervision due to its potential for abuse and serious side effects.
Crystal methamphetamine, on the other hand, is an illegal drug that is produced and sold on the black market. It can be smoked, injected, snorted or swallowed, and it produces a euphoric rush followed by a long-lasting high. Long-term use of crystal methamphetamine can lead to serious health consequences, including addiction, psychosis, dental problems (meth mouth), memory loss, aggression, and cardiovascular damage.
Aquaculture is the controlled cultivation and farming of aquatic organisms, such as fish, crustaceans, mollusks, and aquatic plants, in both freshwater and saltwater environments. It involves the breeding, rearing, and harvesting of these organisms under controlled conditions to produce food, feed, recreational resources, and other products for human use. Aquaculture can take place in a variety of systems, including ponds, raceways, tanks, and cages, and it is an important source of protein and livelihoods for many people around the world.
Oligohymenophorea is a class within the phylum Ciliophora, which includes protozoans commonly known as ciliates. This group is characterized by having a complex ciliary structure called an undulating membrane and a reduced number of oral primordia (hence the name "oligo" meaning few and "hymenophorea" referring to the oral apparatus).
Members of Oligohymenophorea are diverse, ranging from free-living species found in various aquatic environments to parasitic forms that infect animals. Some well-known examples include Tetrahymena, Paramecium, and Ichthyophthirius (the causative agent of "white spot" disease in freshwater fish).
It's important to note that the classification of ciliates has undergone significant revisions in recent years due to advances in molecular biology and ultrastructural studies. As a result, some sources may use different names or classifications for this group.
Metolazone is a medication that belongs to a class of diuretics known as "thiazide-like" diuretics. According to the US National Library of Medicine's MedlinePlus, metolazone works by helping your body get rid of extra salt and water by increasing the amount of urine you produce. This medication is primarily used to treat high blood pressure and fluid buildup due to heart failure.
It is important to note that while I strive to provide accurate information, this definition is intended to be a general summary and may not cover all aspects of the medical term. Therefore, it is always recommended to consult with a healthcare professional or refer to reputable medical resources for detailed and personalized information.
"Freezing" is a term used in the medical field to describe a phenomenon that can occur in certain neurological conditions, most notably in Parkinson's disease. It refers to a sudden and temporary inability to move or initiate movement, often triggered by environmental factors such as narrow spaces, turning, or approaching a destination. This can increase the risk of falls and make daily activities challenging for affected individuals.
Freezing is also known as "freezing of gait" (FOG) when it specifically affects a person's ability to walk. During FOG episodes, the person may feel like their feet are glued to the ground, making it difficult to take steps forward. This can be very distressing and debilitating for those affected.
It is important to note that "freezing" has different meanings in different medical contexts, such as in the field of orthopedics, where it may refer to a loss of joint motion due to stiffness or inflammation. Always consult with a healthcare professional for accurate information tailored to your specific situation.
Novirhabdovirus is not a medical term, but a taxonomic designation for a genus of viruses within the family Rhabdoviridae. These viruses are characterized by having a bullet-shaped virion and a single-stranded, negative-sense RNA genome. They infect a variety of hosts, including fish and birds, and can cause serious diseases. However, they are not known to infect humans or pose a direct threat to human health.
Gills are specialized respiratory organs found in many aquatic organisms such as fish, crustaceans, and some mollusks. They are typically thin, feathery structures that increase the surface area for gas exchange between the water and the animal's bloodstream. Gills extract oxygen from water while simultaneously expelling carbon dioxide.
In fish, gills are located in the gill chamber, which is covered by opercula or protective bony flaps. Water enters through the mouth, flows over the gills, and exits through the opercular openings. The movement of water over the gills allows for the diffusion of oxygen and carbon dioxide across the gill filaments and lamellae, which are the thin plates where gas exchange occurs.
Gills contain a rich supply of blood vessels, allowing for efficient transport of oxygen to the body's tissues and removal of carbon dioxide. The counter-current flow of water and blood in the gills ensures that the concentration gradient between the water and the blood is maximized, enhancing the efficiency of gas exchange.
Nodaviridae is a family of small, non-enveloped viruses with icosahedral symmetry. The genome consists of two positive-sense, single-stranded RNA segments: RNA1 (3.1 kb) encodes the RNA-dependent RNA polymerase and RNA2 (1.4 kb) encodes the capsid protein. A subgenomic RNA3 is also produced from RNA1 during replication, which encodes a non-structural protein involved in viral replication. Nodaviruses infect insects and fish and can cause diseases such as encephalopathy and retinopathy in fish. They are transmitted horizontally through the fecal-oral route and vertically through the egg. Nodaviridae is a member of the order Picornavirales.