Fugu

When Fugu EPO gene and promoter region constructs (six kb) are transfected into human carcinoma prison cell lines transcription is non hypoxia responsive (Chou et al., 2004) and this is supported past a lack of an HIF-binding hypoxia response element (HRE) in the promoter region of Fugu.

From: Fish Physiology , 2009

Quality improvement and fermentation control in fish products

T. Kuda , in Advances in Fermented Foods and Beverages, 2015

16.two.3.2 Nukazuke of pufferfish ovary

Nukazuke of the ovaries of pufferfish ( Fugu no mako zuke) is made in limited regions in Ishikawa Prefecture. The ovaries, which contain a deadly poisonous substance, are salted for at to the lowest degree 1   year and soaked in rice bran for 2   years (Figure 16.5). Although researchers have challenged this mysterious detoxification mechanism for more than thirty   years, no clear answer has been found. Unlike the mutual fish Nukazuke, the puffer ovary Nukazuke requires re-salting several times during the salting process. Past re-salting, a significant corporeality of water-soluble Fugu poison (tetrodotoxin; TTX) is removed. In addition, this poison is further diluted by soaking the ovaries in rice bran. However, microbiology researchers are continuously attracted to this mysterious mechanism and consider that some kind of microbial action, including the conversion and binding, influences the amount of TTX that remains in these organs.

Figure 16.5. Recipe for Nukazuke using ovaries of pufferfish.

The Association of Puffer Fish Processing in Ishikawa Prefecture strictly requires that a Fugu poisonous substance test be conducted per production lot, and a certificate proving that a product passed this test is fastened to every product distributed in the market.

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The development of microbiological risk assessment

S. Notermans , ... F. Rombouts , in Microbiological Chance Assessment in Nutrient Processing, 2002

Eating of pufferfish

In Japan, a dish known equally 'fugu' is, historically, one of the most favoured and heraldic forms of fish eating Nevertheless, consumption of this food has resulted in many deaths, and the problem continues to this day. Consumption of the delicacy was banned in 1550 by the Emperor, afterward a grouping of soldiers had died, but the ban was abolished in 1888 when the Japanese Prime Minister tasted a pocket-sized sample of fugu and survived. This disease is known as blowfish or pufferfish poisoning and is due to the neurotoxic effects of the tetrodotoxin, which occurs in various species of pufferfish. The dish is now prepared only by chefs who have been specially trained and certified by the Japanese government and can exist relied upon to free the flesh of the toxic liver, gonads and peel. Despite these precautions, many cases of tetrodotoxin poisoning are reported each year in people consuming fugu (Source: Medical Journal, 12 June, 2001, vol. 2, no. 6).

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Toxins in Food: Naturally Occurring

D.-F. Hwang , T.-Y. Chen , in Encyclopedia of Nutrient and Health, 2016

Tetrodotoxin

Tetrodotoxin poisoning is caused by consumption of Japan fugu or puffer. However, the toxin has been reported to be present in newts, frogs, octopus, goby fish, starfish, flatworms, xanthid crabs, and diverse gastropods. Puffers are found in subtropical and tropical marine waters but can live in fresh, stagnant, and marine waters. Tetrodotoxin is distributed in all the tissues, especially in the ovaries, roe, liver, intestines, and peel. Those toxic animals are intoxicated through the food chain. The source of tetrodotoxin comes from bacteria, especially Vibrio spp.

Tetrodotoxin is a neurotoxin and is water-soluble and stable to boiling except in an alkaline solution. Toxicity is manifested every bit a tingling or prickly sensation of the fingers and toes; malaise; dizziness; pallor; numbness of the lips, tongue, and extremities; ataxia; nausea, vomiting, and diarrhea; epigastric hurting; dryness of the skin; subcutaneous hemorrhage and desquamation; respiratory distress; muscular twitching, tremor, incoordination, and muscular paralysis; and intense cyanosis. Fatality rates are high.

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Neurobiological Weapons

Peter J. Osterbauer , Michael R. Dobbs , in Clinical Neurotoxicology, 2009

TETRODOTOXIN

General Characteristics

Widely recognized every bit the deadly substance produced by fugu, or puffer fish, tetrodotoxin works at the level of the cell membrane. The toxin binds tightly to voltage-gated sodium channels, blocking the influx of sodium necessary for conduction of action potentials. 77 Information technology affects peripheral nerves, both motor and sensory, and causes low of medullary respiratory and vasomotor centers. 78 The lethal homo dose is believed 1 to ii mg by ingestion. 19

Potential Methods of Deployment

Tetrodotoxin nigh likely would exist used to contaminate food or water supplies. It is soluble in water that is slightly acidic, and is not affected significantly past extremes of temperature. nineteen Chlorine readily inactivates the toxin under acidic (pH < 3) and alkalinic (pH > 9) conditions. 19

Clinical Aspects

Initial symptoms of oral numbness, gastrointestinal distress, anxiety, headache, and balmy peripheral weakness brainstorm to appear within 10 minutes to four hours of ingestion. This is followed by an ascending, generalized paralysis, hypotension, convulsions, and cardiac arrhythmias. Expiry occurs in four to half dozen hours secondary to respiratory failure. 19, 78 Distressingly, the victim may remain witting, although paralyzed, until but before expiry.

No specific treatment is known for tetrodotoxin poisoning; handling is supportive. Empirical gastric lavage with activated charcoal and administration of anticholinergic agents may be benign; however, insufficient information are available to assess adequately the efficacy of these options. 78

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Natural Toxins in Animal Foodstuffs

Takayuki Shibamoto , Leonard F. Bjeldanes , in Introduction to Food Toxicology, 1993

three Chemistry of Tetrodotoxin

In 1909, a crude sample of the principal fugu poisonous substance (0.two%) was isolated and named tetrodotoxin. Additional chemical studies on tetrodotoxin accept been conducted since then and many researchers have tried to elucidate its very complex structure. X-ray analyses of sure tetrodotoxin derivatives take finally enabled researchers to empathise its structure ( Effigy 4.8) and to subsequently develop the chemical synthesis of tetrodotoxin.

Figure 4.8. Structure of tetrodotoxin.

Tetrodotoxin is an amino perhydroquinazoline compound with a molecular formula of CelevenH17Due northiii. It is a colorless prism that in aqueous solution is a mono-acidic base with a pKa of 8.five. It is only sparingly soluble in h2o except in a slightly acidic status, yet at low pH it is not indefinitely stable. In alkaline conditions tetrodotoxin is readily degraded into several quinazoline compounds. The normally high pGranda of the guanidine grouping of tetrodotoxin is masked past the acidic OH group at Cx which has a pMa of nearly 8.5. The end NH2 group enters into germination of a Zwitterion with i of the OH groups. The toxicities of tetrodotoxin derivatives depend upon the substituent on C4. The relative lethalities of the derivatives are shown in Table 4.v.

Table 4.5. Relative Lethalities of Tetrodotoxin and Its Derivatives

Compound Group on Cfour a Relative lethality
Tetrodotoxin —OH 1.000
Anhydrotetrodotoxin —O— 0.001
Tetrodaminotoxin —NH2— 0.010
Methoxytetrodotoxin —OCH3 0.024
Ethoxytetrodotoxin —OC2H5 0.012
Deoxytetrodotoxin —Hs 0.079
Tetrodonic acid — 0.000
a
Refer to Figure 4.8.

The oxygen link betwixt C5 and Cten in tetrodotoxin seems to be essential if the derivative is to be toxic. This is evident because tetrodonic acid, which does not accept this oxygen link, is nontoxic.

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Parathyroid Hormone Family unit

Nobuo Suzuki , in Handbook of Hormones, 2016

Supplemental Information

Eastward-Figure 26.1. Alignment of the amino acid sequences of the fugu PTH family.

Fugu PTHrPA (GenBank accession number CAB94712), fugu PTHrPB (AJ639925), fugu PTH1 (CAG26461), fugu PTH2 (AAQ73561), and fugu PTH-similar (CAG26462) were analyzed using the eclustal programme (world wide web.genome.jp/tools/clustalw/). Arrows indicate the beginning of each mature peptide, and the horizontal bar above each sequence shows the extent of amino acids 1–34 in the N-terminus. Conserved amino acid sequences are indicated by asterisks.

East-Figure 26.2. Amino acrid sequences of human TIP39 (tuberoinfundibular peptide of 39 amino acids) (GenBank accretion number NP_848544).

The sequence of man TIP39 was compared with human 1–34 PTH1 and human 1–34 PTHrP. Conserved amino acrid sequences are indicated past asterisks.

E-Table 26.1. Accession Numbers of Vertebrate PTHs, PTHrPs, and PTH-Like (PTH-L) Proteins Used in Figure 26.ane

PTH1 PTH2 PTHrPA PTHrPB PTH-like Protein
Man NM_000315 NP_945317
Cattle NP_776379 NP_777178
Rat NP_05874
Mouse NP_032996
Chicken ABY47639 NP_990669 FM955443
Xenopus FM955441
Flounder CAD58826
Zebrafish NP_998115 NP_998114 NP_001019798 NP_001036789 XM_005168285
Fugu CAG26461 AAQ73561 CAB94712 AJ639925 CAG26462
Elephant shark GU584186 GU584187 GU584188

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Cell Glycobiology and Development; Health and Disease in Glycomedicine

T. Seya , in Comprehensive Glycoscience, 2007

iv.01.three TLR Subfamilies Specific to Fish

A number of bioinformatics findings from genome projects have suggested that fugu (puffer fish, Takifugu rubripes) possesses a TLR system similar to the human being. five The TLR system in homo may therefore be compatible with those of other vertebrate species. Fugu has the fish-specific TLRs (TLR21, 22, 23, and TLR14) in addition to the human counterparts of the TLRs (TLR2, three, 5, 7, viii, and 9) (Figures 2 and iii). Furthermore, fugu has a soluble form of TLR5 (TLR5S), which has been reported to deed as an amplifier of membrane TLR5 signaling. 6 This TLR5S function somewhat resembles that of soluble CD14 in the TLR4 function complex. 6,thirteen TLR23 is structurally homologous to TLR21 and 22, although their functional properties have not been determined. The functional features of TLR14 are non known nonetheless. If these molecules are confirmed as members of the TLR family, then a prototype of the TLR organization emerged about 500 meg years ago and the genes have been primarily preserved in the TLR system of vertebrates. 14–16 Nosotros speculate that fish require TLR21 and 22 for living in water but mammals and birds have lost these TLRs because they have not proved to exist essential for living on land. The natural ligands for fish-specific TLRs are non formally identified yet. Molecular assay in the context of structural biology will be necessary to identify the molecular interrelationships between TLR and their various ligands, that is, the executions of self-pathogen discrimination.

Figure 2. Fish-specific TLRs. TLRs deduced from the Fugu genome project are illustrated according to the DDBJ/EMBL/NCBI database and motif search analysis. See Ref. half-dozen for the information on TLR14 and TLR23, and Ref. four for TLR21 and TLR22. Their functional data will be presented elsewhere.

Figure 3. Role of fish TLRs. Functional properties of TLR5S, 21, and 22 in Takifugu rubripes are schematically illustrated in comparing with those of human being TLRs. (Panel a) Fugu TLR5S recognizes flagellin and amplifies the signal induced by the membrane TLR5. (Console b) TLR21selectively recognizes bacterial lipoprotein (BLP) in any form. In contrast, in humans, the circuitous of TLT2/6 recognizes diacylated BLP, whereas the complex of TLR2/1 recognizes triacylated BLP. (Panel c) TLR22 recognizes polyI:C (an analog of double strand (ds)RNA). Fish besides equally humans have TLR3 that recognizes polyI:C. Thus, fish possess two sorts of dsRNA-recognition receptors on the cell membrane leading to efficient type I interferon induction. Other TLRs, including TLR23 , accept not been functionally characterized yet.

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Phycotoxins

A. Sharma , ... S. Kumar , in Encyclopedia of Food Microbiology (Second Edition), 2014

Tetrodotoxin

Tetrodotoxin (TTX) is nowadays in pufferfish too called blowfish (fugu) or sea squab. TTX really is produced by marine leaner every bit well every bit by intestinal microflora of TTX-producing fish. The bacteria include Vibrio alginolyticus, Vibrio damsela, Streptococcus sp., Bacillus sp., and Pseudomonas sp., which lead a parasitic or symbiotic being on pufferfish. These bacteria take been institute to be epiphytic on the species of calcareous algae, Jania sp., and Alteromonas sp., on which these fishes usually feed. TTX blocks the sodium pump. It binds to the sodium channel in nervus cells and blocks the propagation of nervus impulses. This causes elimination of electric differential created by the influx of sodium and efflux of potassium ions. The onset of poisoning could be as soon as 10–45 min afterwards consumption. It involves nausea, vomiting, and diarrhea, followed by dizziness, tingling of lips and extremities, paralysis, respiratory arrest, and death.

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Euryhaline Fishes

William S. Marshall , in Fish Physiology, 2012

5.4 Genomics and Proteomics

The estuarine fish genomes available are expanding and the genomes of several euryhaline species – fugu ( Takifugu nigroviridis), 3-spined stickleback (Gasterosteus aculeatus), and mummichog (Fundulus heteroclitus) – are consummate or almost so, so that there will exist more admission to full genomic models in the near hereafter (Table 8.1). Given the huge commercial importance and deep expressed sequence tag (EST) file, it is surprising that Nile tilapia has attracted less scientific interest than its cousin Mozambique tilapia (355 ESTs submitted). Scientists could do well to shift attention to Nile tilapia, the most aquacultured euryhaline teleost on the planet, and a critical protein source for many developing nations. These genomic advances will allow full molecular manipulation experiments to be performed, thus opening new and exciting possibilities for understanding the acclimation processes to various combinations of stressors oft faced past estuarine species. The studies volition be made all the more interesting because of the ancient total genomic duplication event in the actinopterygian fish lineage (Cutler and Cramb, 2001; Larhammar et al., 2009). The biomonitoring role of the estuarine genomic fish model Fundulus heteroclitus has been demonstrated in a recent written report examining salinity gradients and the effects of salinity variation in the habitat with genetic variation in the important clusters of osmoregulatory genes (Whitehead, 2010; Whitehead et al., 2011b). With careful and ongoing documentation of the genomic database (Paschall et al., 2004), comparative transcriptomics can reveal essential functional genes that allow the northern subspecies of the mummichog to be stronger hypoosmoregulators. Key to effective hypoosmoregulation in FW is reduction in passive permeability through the evolution of effective tight junctions in peel and gill epithelia, supportive calcium metabolism and speedily responsive (vi   h) osmotic stress factors (OSTF1), and aquaporin3 (AQP3) genes (Whitehead et al., 2011b) that aid to maintain junctional integrity and enhance basolateral hydraulic electrical conductivity in aid of jail cell book regulation. A few well-placed transcriptomic studies have provided many physiological questions that can be answered using genomic techniques, such equally selective knockout and knockdown approaches to revealing the functional importance of sure genes. For instance, morpholino knockdown techniques accept been adult in mummichogs to test cytochrome P450-1A (CYP-1A) in examining the office of this enzyme in detoxification (Matson et al., 2008), and in zebrafish to discern the role of Rhcg1 in ammonium and Na+ ship (Kumai and Perry, 2011). Importantly, multiple genes of unknown function will be highlighted and subsequently their functions can exist revealed.

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Concluding Differentiation: REST

S. Aigner , Yard.W. Yeo , in Encyclopedia of Neuroscience, 2009

Residual/NRSF: Gene Organisation, Alternative Splicing, and Protein Construction

The Residual/NRSF gene and its exon structure are evolutionarily conserved from human to fugu (pufferfish). The cistron is non found in flies or nematodes, suggesting that REST/NRSF is specific to the vertebrate lineage. It consists of three alternative get-go exons (exons I–III), located in the v′ untranslated region (5′ UTR); three constitutively spliced exons (Iv–Half-dozen); and a short (28 base pairs) alternatively spliced internal exon (exon N). The full-length REST/NRSF protein comprises iii known functional domains: a Dna-binding domain and two repressor domains, which are located at the North- and C-termini of the protein. The ii repressor domains function independently of each other and serve to recruit singled-out transcriptional regulation complexes ( Figure 1(b) ). The protein also has lysine- and proline-rich regions; nonetheless, their significance is unknown. REST/NRSF's DNA bounden domain encompasses an assortment of eight highly conserved zinc fingers, small-scale independently folded nucleic acid binding motifs found in many other sequence-specific nucleic acrid binding proteins. Thus, with its repressor and DNA bounden domains, Residuum/NRSF shows an architecture typical of nearly transcription factors.

Figure 1. (a) Structure of the REST/NRSF cistron and alternative isoform REST4. Exons are indicated equally boxes and introns as dashed lines. Exon numbers in roman characters from I to 6 are shown above the corresponding exons; the neuronal-specific exon located between exons 5 and Half dozen is indicated as exon N. Exons I–III are alternative v′ UTRs that are spliced to exon Iv, represented by lines connecting exons at the intron–exon boundaries. Lines to a higher place the primary transcript represent the Residue/NRSF master isoform, and lines below the master transcript represent the REST4 alternative isoform. Arrows indicate termination codons for REST/NRSF and REST4. (b) Balance/NRSF protein includes eight zinc fingers near the North-terminal repressor domain and one zinc finger in the C-last domain. Residuum/NRSF contains a lysine-rich and a proline-rich region upstream of the C-terminal repressor domain. REST4 includes exon N, leading to a truncated protein encompassing the Northward-terminal repressor domain and five zinc fingers. (c) The conserved REST/NRSF Dna bounden site, termed NRSE/RE1, is approximately 21   bp of long and contains of ii highly conserved half-site motifs that are separated by ii non conserved nucleotides and are flanked past several poorly conserved nucleotides. In this delineation of conserved mammalian NRSE/RE1 sites, generated with pictogram (http://genes.mit.edu/pictogram), the degree of conservation at each position is represented by the size of the nucleotide letter.

Although little is known about the role of alternative splicing events that affect the 5′ UTR of the REST/NRSF cistron, the splice variant produced past inclusion of exon N, located within the region of the gene that encodes the Deoxyribonucleic acid bounden domain, has received a neat bargain of attending because it is primarily found in neurons. Its poly peptide production, termed REST4, is a truncated version of REST/NRSF that terminates subsequently the fifth zinc finger and therefore lacks the C-concluding repressor domain ( Effigy 1(a) ). Thus, REST4 is likely to have a function distinct from full-length REST/NRSF, which volition be discussed afterwards.

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