[17] Thus, reduction in water toxicity may help regulate the balance of marine food webs and decrease mortality rates of finfish, marine mammals, and sea birds. All Polykrikos species have: 1) a slightly curved longitudinal furrow, sulcus, extending to posterior end of the organism 2) a loop-shaped acrobase, which is an anterior extension from the sulcus 3) a transverse furrow, cingulum, with the displacement 4) taeniocyst-nematocyst complexes 5) two or four times less the number of nuclei than of zooids, and 6) ability to disassemble into pseudocolonies with fewer zooids and only one nucleus. Very few planozygotes went through a resting cyst stage. Contreras. Toxin group Toxin producing species Class Characteristics Mode of action Structure Domoic acid: Pseudo-nitzschia spp. Cytoplasm of Polykrikos is characterized by numerous rough endoplasmic reticulum nets, Golgi complexes and vacuoles. Some gonyaulacoid dinoflagellates and single species of gymnodinoid, Gymnodinium catenatum, are known to produce STX or GTXs, and these dinoflagellates have the longer sxtA transcript that includes the A4 domain [33 ,57 ]. It is also seen as solitary cells with a green-brown colour. [13][8], Polykrikos hartmannii is a phototrophic dinoflagellate and has been reported in waters of Canada,[14] USA, Mexico, China, India, Japan, Korea,. doi:10.1016/j.imbio.2014.07.006. Polykrikos have been found to regulate algal blooms as they feed on toxic dinoflagellates. Presence of specialised NTC and large cell size might have triggered multiple losses of photosynthesis. [11] has demonstrated that P. lebouriae have peridinin-type plastids that were most likely acquired from ancestral polykrikoids. It is usually seen in long, swimming chains of tiny cells, with up to 32 cells in a chain (occasionally 64). Polykrikos geminatus (F.Schütt) D.X.Qiu & Senjie Lin, G. catenatum is a photosynthetic dinoflagellate that is most notable as the only naked dinoflagellate known to be responsible for paralytic shellfish poisoning (PSP), a neurotoxic poisoning syndrome which affects human consumers of contaminated shellfish. Cor marrón-verdosa, debidas ós dinoflaxelados Karenia mikimotoi e Prorocentrum minimum. Files are available under licenses specified on their description page. Gymnodinium catenatum Graham 1943– This species was originally described by Graham from a bloom in the Gulf of California, with a 384 word description in English . Only one species is known to be exclusively autotrophic (P. geminatum), while some lack the plastid and are completely heterotrophic (P. grassei, P. herdmanae, P. kofoidii and P. The dinoflagellates (class Dinophyceae) are the most notorious producers of toxins. El texto está disponible bajo la Licencia Creative Commons Atribución Compartir Igual 3.0; pueden aplicarse cláusulas adicionales.Al usar este sitio, usted acepta nuestros términos de uso y nuestra política de privacidad. [5], Polykrikos was first seen in 1868 by Uljanin and was mistakenly considered as a metazoan larva of a turbellarian flatworms. The most distinctive feature of polykrikoids is their formation of multinucleate "pseudocolonies" consisting of an even number of subunit zooids.The two genera differ in number of nuclei; possessing two nuclei regardless of the number of zooids is a synapomorphy for Polykrikos, whereas Pheopolykrikos possess equal numbers of nuclei and zooids. Under culture conditions most organisms undergone meiosis and directly entered vegetative cycle. Polykrikos (from Greek “poly” - many, and “krikos” – ring or circle) is one of the genera of family Polykrikaceae that includes athecate pseudocolony-forming dinoflagellates. Polykrikos tentaculatus O.Wetzel [18], "Molecular phylogeny of ocelloid-bearing dinoflagellates (Warnowiaceae) as inferred from SSU and LSU rDNA sequences", "First Clear View of a One-Celled Harpooner in Action", "Microbial arms race: Ballistic "nematocysts" in dinoflagellates represent a new extreme in organelle complexity", "Single-cell transcriptomics using spliced leader PCR: Evidence for multiple losses of photosynthesis in polykrikoid dinoflagellates", "Grazing impacts of the heterotrophic dinoflagellate, "Reduction in the toxicity of the dinoflagellate, https://en.wikipedia.org/w/index.php?title=Polykrikos&oldid=951287988, Creative Commons Attribution-ShareAlike License, This page was last edited on 16 April 2020, at 12:27. 麻痺性貝毒 (PSP: Paralytic Shellfish Poison) 毒成分:サキシトキシン (saxitoxin, STX)、テトロドトキシン (tetrodotoxin, TTX)、ゴニオトキシン (gonyautoxin, GTX) などによる 。; 毒化原因:、渦鞭毛藻類の Protogonyaulax tamarensis,Protogonyaulax catenella, Alexandrium tamarense, Gymnodinium catenatum、ビブリオ属の Vibrio alginolyticusなど。 Gymnodinium is a genus of dinoflagellates, a type of marine and freshwater plankton. [7] Gradual increase in size of Polykrikos makes the organisms great predators, but increase in body size of single cells is known to result in increased self-shading of chloroplasts and decreased surface area to volume ratio, leading to decreased photosynthetic efficiency. Within the group there is some variation in which organelles are presented, but trichocysts, nematocysts, taeniocysts, mucocysts and plastids have been observed from different members within the taxon.[8]. This page was last edited on 22 January 2012, at 10:14. The cyst stage persisted for 1 month, which is considered as a relatively short period in comparison to other dinoflagellates, which obligate dormancy period may reach up to 6 month. Single cell or chain-forming species. Further studies on molecular mechanisms of detoxification by Polykrikos maybe helpful in biomedical and environment-monitoring fields. All structured data from the file and property namespaces is available under the Creative Commons CC0 License; all unstructured text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. Gymnodinium komt in alle wateren voor. Polykrikos are characterized by a sophisticated ballistic apparatus,[2] named the nematocyst-taeniocyst complex, which allows species to prey on a variety of organisms. Each zooid has a pair of flagella (transverse and longitudinal flagella) and has its own transverse groove, cingulum, but zooid longitudinal furrows, sulci, are fused. Vegetative form doubled zooids and subsequently split into four gametes of a 2-zooid-1-nucleus form. Sommige soorten Gymnodinium vormen kettingachtige kolonies, zoals o.a. Thus, human consumption of seafoods harvested from areas where these dinoflagellates thrive in abundance (i.e., algal blooms) can lead to the outbreak of paralytic poisoning. Several bloom-forming and toxin producing species are known (e.g., Gynbidinium catenatum, Fig. Dentro desta familia lévanse descritas 21 variedades, entre as que destacan as carbamate toxinas (STX) e … Voorkoming. Characteristics. [10] Organelles are located in proximity, but lie within different membranes and are separated by a passage, called “chute”. Materials and Methods 2.1. In this study, the oxidative stress and genotoxic responses of mussels (Mytilus galloprovincialis) exposed to paralytic shellfish toxin (PST) - producing dinoflagellates Gymnodinium catenatum were evaluated under i) … [11], For the genus of Polykrikos, detailed data is available on reproduction of a type species (holotype) P. kofoidii, whose life cycle resembles general dinoflagellate cycle as vegetative cells form gametes that fuse to form a diploid (2n) zygote that could encyst, but pseudocolonial nature adds a number of peculiarities to the Polykrikos development.[12]. However, molecular data analysis by Gavelis et al. Sommige soorten Gymnodinium vormen kettingachtige kolonies, zoals o.a. The results may contribute to the current understanding of the viral regulatory role in algal bloom events. It has been observed many times all over the world . Cor marrón-vermella, debidas a diatomeas (dos xéneros Chaetoceros, Rhizosolenia etc.) The giant lions paw scallop releases both eggs and sperm during each annual spawn. However, some Polykrikos pose a health risk to certain fishes, while the bloom-regulating ones are often preyed on by marine invertebrates, like amphipods, which would return the toxins back into the food web. The nematocyst is a larger organelle and lies posterior to taeniocyst. [17] Some polykrikoid population monitoring and investigation of toxin dynamics inside the body of grazers could provide better understanding of plankton-based food webs, estimate degrees of poisoning in ecosystems and propose potential toxin elimination routes. 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