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Hon Cheung Lee - One of the best experts on this subject based on the ideXlab platform.
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cd38 produces nicotinic acid adenosine dinucleotide phosphate in the lysosome
Journal of Biological Chemistry, 2018Co-Authors: Cheng Fang, Hon Cheung Lee, Qi Wen Deng, Ya Jie Chen, Yun Nan Hou, Yong Juan ZhaoAbstract:Nicotinic acid adenosine dinucleotide phosphate (NAADP) is a Ca2+-mobilizing second messenger that regulates a wide range of biological activities. However, the mechanism of its biogenesis remains controversial. CD38 is the only enzyme known to catalyze NAADP synthesis from NADP and nicotinic acid. CD38-mediated catalysis requires an acidic pH, suggesting that NAADP may be produced in acidic endolysosomes, but this hypothesis is untested. In this study, using human cell lines, we specifically directed CD38 to the endolysosomal system and assessed cellular NAADP production. First, we found that nanobodies targeting various epitopes on the C-terminal domain of CD38 could bind to cell surface–localized CD38 and induce its endocytosis. We also found that CD38 internalization occurred via a clathrin-dependent pathway, delivered CD38 to the endolysosome, and elevated intracellular NAADP levels. We also created a CD38 variant for lysosome-specific expression, which not only withstood the degradative environment in the lysosome, but was also much more active than WT CD38 in elevating cellular NAADP levels. Supplementing CD38-expressing cells with nicotinic acid substantially increased cellular NAADP levels. These results demonstrate that endolysosomal CD38 can produce NAADP in human cells. They further suggest that CD38's compartmentalization to the lysosome may allow for its regulation via substrate access, rather than enzyme activation, thereby providing a reliable mechanism for regulating cellular NAADP production.
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cyclic gmp dependent and independent effects on the synthesis of the calcium messengers cyclic adp ribose and nicotinic acid adenine dinucleotide phosphate
Journal of Biological Chemistry, 1998Co-Authors: Richard M Graeff, Luisa Franco, A De Flora, Hon Cheung LeeAbstract:Abstract Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP) have been shown to mobilize intracellular Ca2+ stores by totally independent mechanisms, which are pharmacologically distinct from that activated by inositol trisphosphate. Although cADPR and NAADP are structurally and functionally different, they can be synthesized by a single enzyme having ADP-ribosyl cyclase activity. In this study, three different assays were used to measure the metabolism of cADPR in sea urchin egg homogenates including a radioimmunoassay, a Ca2+release assay, and a thin layer chromatographic assay. Soluble and membrane-bound ADP-ribosyl cyclases were identified and both cyclized NAD to produce cADPR. The soluble cyclase was half-maximally stimulated by 5.3 μm cGMP, but not by cAMP, while the membrane-bound form was independent of cGMP. The two forms of the cyclase were also different in the pH dependence of utilizing nicotinamide guanine dinucleotide (NGD), a guanine analog of NAD, as substrate, indicating they are two separate enzymes. The stimulatory effect of cGMP required ATP or ATPγS (adenosine 5′-O-(3-thiotriphosphate)) and a cGMP-dependent kinase activity was shown to be present in the soluble fraction. The degradation of cADPR to ADP-ribose was catalyzed by cADPR hydrolase, which was found to be predominantly associated with membranes. Similar to the membrane-bound cyclase, the cADPR hydrolase activity was also independent of cGMP. Both the soluble and membrane fractions also catalyzed the synthesis of NAADP through exchanging the nicotinamide group of NADP with nicotinic acid (NA). The base-exchange activity was independent of cGMP and the half-maximal concentrations of NADP and NA needed were about 0.2 mm and 10 mm, respectively. The exchange reaction showed a preference for acidic pH, contrasting with the neutral pH optimum of the cyclase activities. The complex metabolic pathways characterized in this study indicate that there may be a multitude of regulatory mechanisms for controlling the endogenous concentrations of cADPR and NAADP.
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adp ribosyl cyclase and cd38 catalyze the synthesis of a calcium mobilizing metabolite from NADP
Journal of Biological Chemistry, 1995Co-Authors: Robert Aarhus, Richard M Graeff, Deborah M Dickey, Timothy F Walseth, Hon Cheung LeeAbstract:Abstract ADP-ribosyl cyclase catalyzes the cyclization of NAD++ to produce cyclic ADP-ribose (cADPR), which is emerging as an endogenous regulator of the Ca2+2+-induced Ca2+2+ release mechanism in cells. CD38 is a lymphocyte differentiation antigen which has recently been shown to be a bifunctional enzyme that can synthesize cADPR from NAD++ as well as hydrolyze cADPR to ADP-ribose. In this study, we show that both the cyclase and CD38 can also catalyze the exchange of the nicotinamide group of NADP++ with nicotinic acid (NA). The product is nicotinic acid adenine dinucleotide phosphate (NAADP++), a metabolite we have previously shown to be potent in Ca2+2+ mobilization (Lee, H. C., and Aarhus, R.(1995) J. Biol. Chem. 270, 2152-2157). The switch of the catalysis to the exchange reaction requires acidic pH and NA. The half-maximal effective concentration of NA is about 5 mM for both the cyclase and CD38. In the absence of NA or at neutral pH, the cyclase converts NADP++ to another metabolite, which is identified as cyclic ADP-ribose 2′-phosphate. Under the same conditions, CD38 converts NADP++ to ADP-ribose 2′-phosphate instead, which is the hydrolysis product of cyclic ADP-ribose 2′-phosphate. That two different products of ADP-ribosyl cyclase and CD38, cADPR and NAADP+, are both involved in Ca2+ mobilization suggests a crucial role of these enzymes in Ca2+ signaling.
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a derivative of NADP mobilizes calcium stores insensitive to inositol trisphosphate and cyclic adp ribose
Journal of Biological Chemistry, 1995Co-Authors: Hon Cheung Lee, Robert AarhusAbstract:We have previously shown that alkaline treatment of NADP generates a derivative which can mobilize Ca2+ from sea urchin egg homogenates (Clapper, D. L., Walseth, T. F., Dargie, P. J., and Lee, H. C. (1987) J. Biol. Chem. 262, 9561-9568). In this study, the active derivative was purified and shown by high pressure liquid chromatography to be distinct from NADP and NADPH. However, its proton NMR spectrum was virtually identical to that of NADP. The mass of its molecular ion was measured by high resolution mass spectrometry to be 743.0510, one mass unit larger than the corresponding ion of NADP. These results are consistent with the active derivative being nicotinic acid adenine dinucleotide phosphate (NAADP). Ca2+ release induced by NAADP was saturable with a half-maximal concentration of about 30 nM. The release was specific since NADP and nicotinic acid adenine dinucleotide were ineffective even at 10-40-fold higher concentrations. The NAADP-dependent Ca2+ release showed desensitization and was insensitive to heparin and a specific antagonist of cyclic ADP-ribose (cADPR), 8-amino-cADPR. The release mechanism did not require calmodulin. This is similar to the inositol trisphosphate-sensitive release but distinct from that of cADPR. That the NAADP-sensitive Ca2+ stores were different from those sensitive to inositol trisphosphate- or cADPR was further indicated by their differences in distribution on Percoll density gradients. Microinjection of NAADP into live sea urchin eggs induced transient elevation of intracellular Ca2+ and triggered the cortical reaction, indicating the NAADP-dependent mechanism is operative in intact cells.
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A derivative of NADP mobilizes calcium stores insensitive to inositol trisphosphate and cyclic ADP-ribose
'American Society for Biochemistry & Molecular Biology (ASBMB)', 1995Co-Authors: Hon Cheung Lee, Aarhus RAbstract:We have previously shown that alkaline treatment of NADP generates a derivative which can mobilize Ca2+ from sea urchin egg homogenates (Clapper, D. L., Walseth, T. F., Dargie, P. J., and Lee, H. C. (1987) J. Biol. Chem. 262, 9561-9568). In this study, the active derivative was purified and shown by high pressure liquid chromatography to be distinct from NADP and NADPH. However, its proton NMR spectrum was virtually identical to that of NADP. The mass of its molecular ion was measured by high resolution mass spectrometry to be 743.0510, one mass unit larger than the corresponding ion of NADP. These results are consistent with the active derivative being nicotinic acid adenine dinucleotide phosphate (NAADP). Ca2+ release induced by NAADP was saturable with a half-maximal concentration of about 30 nM. The release was specific since NADP and nicotinic acid adenine dinucleotide were ineffective even at 10-40-fold higher concentrations. The NAADP-dependent Ca2+ release showed desensitization and was insensitive to heparin and a specific antagonist of cyclic ADP-ribose (cADPR), 8-amino-cADPR. The release mechanism did not require calmodulin. This is similar to the inositol trisphosphate-sensitive release but distinct from that of cADPR. That the NAADP-sensitive Ca2+ stores were different from those sensitive to inositol trisphosphate- or cADPR was further indicated by their differences in distribution on Percoll density gradients. Microinjection of NAADP into live sea urchin eggs induced transient elevation of intracellular Ca2+ and triggered the cortical reaction, indicating the NAADP-dependent mechanism is operative in intact cells.link_to_subscribed_fulltex
Eduardo N Chini - One of the best experts on this subject based on the ideXlab platform.
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nicotinic acid adenine dinucleotide phosphate a new ca2 releasing agent in kidney
Journal of The American Society of Nephrology, 2001Co-Authors: Jingfei Cheng, Eduardo N Chini, Ahad N K Yusufi, Michael A Thompson, Joseph P GrandeAbstract:Abstract . Nicotinic acid adenine dinucleotide phosphate (NAADP), a molecule derived from β-NADP, has been shown to trigger Ca 2+ release from intracellular stores of invertebrate eggs and mammalian cell microsomes. NAADP-induced Ca 2+ release occurs through a mechanism distinct from that of inositol-1,4,5-trisphosphate— or cyclic ADP-ribose—elicited Ca 2+ release. This study investigated whether NAADP can be synthesized in rat kidney. Extracts from glomeruli, mesangial cells, and papilla have high NAADP synthetic capacities. Conversely, synthesis of NAADP in kidney cortex was almost undetectable. Furthermore, 9- cis -retinoic acid significantly up-regulated NAADP synthesis in mesangial cells. Authenticity of NAADP biosynthesis in glomeruli was affirmed by HPLC analysis. NAADP stimulated Ca 2+ release from mesangial cell microsomes through a pathway distinct from that of inositol-1,4,5-trisphosphate or cyclic ADP-ribose. NAADP-triggered Ca 2+ release may play an important role in regulation of renal function.
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ca2 release triggered by nicotinate adenine dinucleotide phosphate in intact sea urchin eggs
Biochemical Journal, 1995Co-Authors: Carmen Perezterzic, Eduardo N Chini, Thomas P Dousa, S S Shen, David E ClaphamAbstract:Nicotinate adenine dinucleotide phosphate (NAADP) was recently identified [Lee and Aarhus (1995) J. Biol. Chem. 270, 2152-2157; Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] as a potent Ca(2+)-releasing agent in sea urchin egg homogenates. NAADP triggered Ca2+ release by a mechanism that was distinct from inositol 1,4,5-trisphosphate (InsP3)- and cyclic ADP-ribose (cADPR)-induced Ca2+ release. When NAADP was microinjected into intact sea urchin eggs it induced a dose-dependent increase in cytoplasmic free Ca2+ which was independent of the extracellular [Ca2+]. The Ca2+ waves elicited by microinjections of NAADP originated at the site of injection and swept across the cytosol. As previously found in sea urchin egg homogenates, NAADP-induced Ca2+ release in intact eggs was not blocked by heparin or by prior desensitization to InsP3 or cADPR. Thio-NADP, a specific inhibitor of the NAADP-induced Ca2+ release in sea urchin homogenates [Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] blocked NAADP (but not InsP3 or cADPR) injection-induced Ca2+ release in intact sea urchin eggs. Finally, fertilization of sea urchin eggs abrogated subsequent NAADP-induced Ca2+ release, suggesting that the NAADP-sensitive Ca2+ pool may participate in the fertilization response. This study demonstrates that NAADP acts as a selective Ca(2+)-releasing agonist in intact cells.
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nicotinate adenine dinucleotide phosphate naadp triggers a specific calcium release system in sea urchin eggs
Journal of Biological Chemistry, 1995Co-Authors: Eduardo N Chini, Kelly W Beers, Thomas P DousaAbstract:Abstract Transient fluxes of intracellular ionized calcium (Ca) from intracellular stores are integral components of regulatory signaling pathways operating in numerous biological regulations, including in early stages of egg fertilization. Therefore, we explored whether NADP, which is rapidly generated by phosphorylation of NAD upon fertilization may, directly or indirectly, exert a regulatory role as a trigger of Ca release from intracellular stores in sea urchin eggs. NADP had no effect, but we found that the deamidated derivative of NADP, nicotinate adenine dinucleotide phosphate (β-NAADP), is a potent and specific stimulus (ED 16 nM) for Ca release in sea urchin egg homogenates. NAADP triggers the Ca release via a mechanism which is distinct from the well-known Ca release systems triggered either by inositol-1,4,5-triphosphate (IP3) or by cyclic adenosine diphospho-ribose (cADPR). The NAADP-induced release of Ca is not blocked by heparin, an antagonist of IP3, or by procaine or ruthenium red, antagonists of cADPR. However, it is selectively blocked by thionicotinamide-NADP which does not inhibit the actions of IP3 or cADPR. NAADP produced by heating of NADP in alkaline (pH = 12) medium or synthetized enzymatically by nicotinic acid-NADP reaction catalyzed by NAD glycohydrolase have identical properties. The results presented herein thus describe a novel endocellular Ca-releasing system controlled by NAADP as a specific stimulus. The NAADP-controlled Ca release system may be an integral component of multiple intracellular regulations occurring in fertilized sea urchin eggs, which are mediated by intracellular Ca release, and may also have similar role(s) in other tissues.
Thomas P Dousa - One of the best experts on this subject based on the ideXlab platform.
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ca2 release triggered by nicotinate adenine dinucleotide phosphate in intact sea urchin eggs
Biochemical Journal, 1995Co-Authors: Carmen Perezterzic, Eduardo N Chini, Thomas P Dousa, S S Shen, David E ClaphamAbstract:Nicotinate adenine dinucleotide phosphate (NAADP) was recently identified [Lee and Aarhus (1995) J. Biol. Chem. 270, 2152-2157; Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] as a potent Ca(2+)-releasing agent in sea urchin egg homogenates. NAADP triggered Ca2+ release by a mechanism that was distinct from inositol 1,4,5-trisphosphate (InsP3)- and cyclic ADP-ribose (cADPR)-induced Ca2+ release. When NAADP was microinjected into intact sea urchin eggs it induced a dose-dependent increase in cytoplasmic free Ca2+ which was independent of the extracellular [Ca2+]. The Ca2+ waves elicited by microinjections of NAADP originated at the site of injection and swept across the cytosol. As previously found in sea urchin egg homogenates, NAADP-induced Ca2+ release in intact eggs was not blocked by heparin or by prior desensitization to InsP3 or cADPR. Thio-NADP, a specific inhibitor of the NAADP-induced Ca2+ release in sea urchin homogenates [Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] blocked NAADP (but not InsP3 or cADPR) injection-induced Ca2+ release in intact sea urchin eggs. Finally, fertilization of sea urchin eggs abrogated subsequent NAADP-induced Ca2+ release, suggesting that the NAADP-sensitive Ca2+ pool may participate in the fertilization response. This study demonstrates that NAADP acts as a selective Ca(2+)-releasing agonist in intact cells.
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nicotinate adenine dinucleotide phosphate naadp triggers a specific calcium release system in sea urchin eggs
Journal of Biological Chemistry, 1995Co-Authors: Eduardo N Chini, Kelly W Beers, Thomas P DousaAbstract:Abstract Transient fluxes of intracellular ionized calcium (Ca) from intracellular stores are integral components of regulatory signaling pathways operating in numerous biological regulations, including in early stages of egg fertilization. Therefore, we explored whether NADP, which is rapidly generated by phosphorylation of NAD upon fertilization may, directly or indirectly, exert a regulatory role as a trigger of Ca release from intracellular stores in sea urchin eggs. NADP had no effect, but we found that the deamidated derivative of NADP, nicotinate adenine dinucleotide phosphate (β-NAADP), is a potent and specific stimulus (ED 16 nM) for Ca release in sea urchin egg homogenates. NAADP triggers the Ca release via a mechanism which is distinct from the well-known Ca release systems triggered either by inositol-1,4,5-triphosphate (IP3) or by cyclic adenosine diphospho-ribose (cADPR). The NAADP-induced release of Ca is not blocked by heparin, an antagonist of IP3, or by procaine or ruthenium red, antagonists of cADPR. However, it is selectively blocked by thionicotinamide-NADP which does not inhibit the actions of IP3 or cADPR. NAADP produced by heating of NADP in alkaline (pH = 12) medium or synthetized enzymatically by nicotinic acid-NADP reaction catalyzed by NAD glycohydrolase have identical properties. The results presented herein thus describe a novel endocellular Ca-releasing system controlled by NAADP as a specific stimulus. The NAADP-controlled Ca release system may be an integral component of multiple intracellular regulations occurring in fertilized sea urchin eggs, which are mediated by intracellular Ca release, and may also have similar role(s) in other tissues.
Robert Aarhus - One of the best experts on this subject based on the ideXlab platform.
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adp ribosyl cyclase and cd38 catalyze the synthesis of a calcium mobilizing metabolite from NADP
Journal of Biological Chemistry, 1995Co-Authors: Robert Aarhus, Richard M Graeff, Deborah M Dickey, Timothy F Walseth, Hon Cheung LeeAbstract:Abstract ADP-ribosyl cyclase catalyzes the cyclization of NAD++ to produce cyclic ADP-ribose (cADPR), which is emerging as an endogenous regulator of the Ca2+2+-induced Ca2+2+ release mechanism in cells. CD38 is a lymphocyte differentiation antigen which has recently been shown to be a bifunctional enzyme that can synthesize cADPR from NAD++ as well as hydrolyze cADPR to ADP-ribose. In this study, we show that both the cyclase and CD38 can also catalyze the exchange of the nicotinamide group of NADP++ with nicotinic acid (NA). The product is nicotinic acid adenine dinucleotide phosphate (NAADP++), a metabolite we have previously shown to be potent in Ca2+2+ mobilization (Lee, H. C., and Aarhus, R.(1995) J. Biol. Chem. 270, 2152-2157). The switch of the catalysis to the exchange reaction requires acidic pH and NA. The half-maximal effective concentration of NA is about 5 mM for both the cyclase and CD38. In the absence of NA or at neutral pH, the cyclase converts NADP++ to another metabolite, which is identified as cyclic ADP-ribose 2′-phosphate. Under the same conditions, CD38 converts NADP++ to ADP-ribose 2′-phosphate instead, which is the hydrolysis product of cyclic ADP-ribose 2′-phosphate. That two different products of ADP-ribosyl cyclase and CD38, cADPR and NAADP+, are both involved in Ca2+ mobilization suggests a crucial role of these enzymes in Ca2+ signaling.
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a derivative of NADP mobilizes calcium stores insensitive to inositol trisphosphate and cyclic adp ribose
Journal of Biological Chemistry, 1995Co-Authors: Hon Cheung Lee, Robert AarhusAbstract:We have previously shown that alkaline treatment of NADP generates a derivative which can mobilize Ca2+ from sea urchin egg homogenates (Clapper, D. L., Walseth, T. F., Dargie, P. J., and Lee, H. C. (1987) J. Biol. Chem. 262, 9561-9568). In this study, the active derivative was purified and shown by high pressure liquid chromatography to be distinct from NADP and NADPH. However, its proton NMR spectrum was virtually identical to that of NADP. The mass of its molecular ion was measured by high resolution mass spectrometry to be 743.0510, one mass unit larger than the corresponding ion of NADP. These results are consistent with the active derivative being nicotinic acid adenine dinucleotide phosphate (NAADP). Ca2+ release induced by NAADP was saturable with a half-maximal concentration of about 30 nM. The release was specific since NADP and nicotinic acid adenine dinucleotide were ineffective even at 10-40-fold higher concentrations. The NAADP-dependent Ca2+ release showed desensitization and was insensitive to heparin and a specific antagonist of cyclic ADP-ribose (cADPR), 8-amino-cADPR. The release mechanism did not require calmodulin. This is similar to the inositol trisphosphate-sensitive release but distinct from that of cADPR. That the NAADP-sensitive Ca2+ stores were different from those sensitive to inositol trisphosphate- or cADPR was further indicated by their differences in distribution on Percoll density gradients. Microinjection of NAADP into live sea urchin eggs induced transient elevation of intracellular Ca2+ and triggered the cortical reaction, indicating the NAADP-dependent mechanism is operative in intact cells.
Dong Zhang - One of the best experts on this subject based on the ideXlab platform.
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molecular phylogenetics and mitogenomics of three avian dicrocoeliids digenea dicrocoeliidae and comparison with mammalian dicrocoeliids
Parasites & Vectors, 2020Co-Authors: Mian Sayed Khan, Vasyl V Tkach, Nehaz Muhammad, Dong Zhang, Xingquan ZhuAbstract:The Dicrocoeliidae are digenetic trematodes mostly parasitic in the bile ducts and gall bladder of various avian and mammalian hosts. Until recently their systematics was based on morphological data only. Due to the high morphological uniformity across multiple dicrocoeliid taxa and insufficient knowledge of relative systematic value of traditionally used morphological characters, their taxonomy has always been unstable. Therefore, DNA sequence data provide a critical independent source of characters for phylogenetic inference and improvement of the system. We examined the phylogenetic affinities of three avian dicrocoeliids representing the genera Brachylecithum, Brachydistomum and Lyperosomum, using partial sequences of the nuclear large ribosomal subunit (28S) RNA gene. We also sequenced the complete or nearly complete mitogenomes of these three isolates and conducted a comparative mitogenomic analysis with the previously available mitogenomes from three mammalian dicrocoeliids (from 2 different genera) and examined the phylogenetic position of the family Dicrocoeliidae within the order Plagiorchiida based on concatenated nucleotide sequences of all mitochondrial genes (except trnG and trnE). Combined nucleotide diversity, Kimura-2-parameter distance, non-synonymous/synonymous substitutions ratio and average sequence identity analyses consistently demonstrated that cox1, cytb, nad1 and two rRNAs were the most conserved and atp6, nad5, nad3 and nad2 were the most variable genes across dicrocoeliid mitogenomes. Phylogenetic analyses based on mtDNA sequences did not support the close relatedness of the Paragonimidae and Dicrocoeliidae and suggested non-monophyly of the Gorgoderoidea as currently recognized. Our results show that fast-evolving mitochondrial genes atp6, nad5 and nad3 would be better markers than slow-evolving genes cox1 and nad1 for species discrimination and population level studies in the Dicrocoeliidae. Furthermore, the Dicrocoeliidae being outside of the clade containing other xiphidiatan trematodes suggests a need for the re-evaluation of the taxonomic content of the Xiphidiata.
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mitochondrial genomes of two diplectanids platyhelminthes monogenea expose paraphyly of the order dactylogyridea and extensive trna gene rearrangements
Parasites & Vectors, 2018Co-Authors: Dong Zhang, Hong Zou, Jin Zhang, Rong Chen, Ivan Jakovlic, Gui T. WangAbstract:Recent mitochondrial phylogenomics studies have reported a sister-group relationship of the orders Capsalidea and Dactylogyridea, which is inconsistent with previous morphology- and molecular-based phylogenies. As Dactylogyridea mitochondrial genomes (mitogenomes) are currently represented by only one family, to improve the phylogenetic resolution, we sequenced and characterized two dactylogyridean parasites, Lamellodiscus spari and Lepidotrema longipenis, belonging to a non-represented family Diplectanidae. The L. longipenis mitogenome (15,433 bp) contains the standard 36 flatworm mitochondrial genes (atp8 is absent), whereas we failed to detect trnS1, trnC and trnG in L. spari (14,614 bp). Both mitogenomes exhibit unique gene orders (among the Monogenea), with a number of tRNA rearrangements. Both long non-coding regions contain a number of different (partially overlapping) repeat sequences. Intriguingly, these include putative tRNA pseudogenes in a tandem array (17 trnV pseudogenes in L. longipenis, 13 trnY pseudogenes in L. spari). Combined nucleotide diversity, non-synonymous/synonymous substitutions ratio and average sequence identity analyses consistently showed that nad2, nad5 and nad4 were the most variable PCGs, whereas cox1, cox2 and cytb were the most conserved. Phylogenomic analysis showed that the newly sequenced species of the family Diplectanidae formed a sister-group with the Dactylogyridae + Capsalidae clade. Thus Dactylogyridea (represented by the Diplectanidae and Dactylogyridae) was rendered paraphyletic (with high statistical support) by the nested Capsalidea (represented by the Capsalidae) clade. Our results show that nad2, nad5 and nad4 (fast-evolving) would be better candidates than cox1 (slow-evolving) for species identification and population genetics studies in the Diplectanidae. The unique gene order pattern further suggests discontinuous evolution of mitogenomic gene order arrangement in the Class Monogenea. This first report of paraphyly of the Dactylogyridea highlights the need to generate more molecular data for monogenean parasites, in order to be able to clarify their relationships using large datasets, as single-gene markers appear to provide a phylogenetic resolution which is too low for the task.
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three new diplozoidae mitogenomes expose unusual compositional biases within the monogenea class implications for phylogenetic studies
BMC Evolutionary Biology, 2018Co-Authors: Dong Zhang, Hong Zou, Jin Zhang, Rong Chen, Ivan Jakovlic, Gui T. WangAbstract:As the topologies produced by previous molecular and morphological studies were contradictory and unstable (polytomy), evolutionary relationships within the Diplozoidae family and the Monogenea class (controversial relationships among the Discocotylinea, Microcotylinea and Gastrocotylinea suborders) remain unresolved. Complete mitogenomes carry a relatively large amount of information, sufficient to provide a much higher phylogenetic resolution than traditionally used morphological traits and/or single molecular markers. However, their implementation is hampered by the scarcity of available monogenean mitogenomes. Therefore, we sequenced and characterized mitogenomes belonging to three Diplozoidae family species, and conducted comparative genomic and phylogenomic analyses for the entire Monogenea class. Taxonomic identification was inconclusive, so two of the species were identified merely to the genus level. The complete mitogenomes of Sindiplozoon sp. and Eudiplozoon sp. are 14,334 bp and 15,239 bp in size, respectively. Paradiplozoon opsariichthydis (15,385 bp) is incomplete: an approximately 2000 bp-long gap within a non-coding region could not be sequenced. Each genome contains the standard 36 genes (atp8 is missing). G + T content and the degree of GC- and AT-skews of these three mitogenome (and their individual elements) were higher than in other monogeneans. nad2, atp6 and nad6 were the most variable PCGs, whereas cox1, nad1 and cytb were the most conserved. Mitochondrial phylogenomics analysis, conducted using concatenated amino acid sequences of all PCGs, indicates that evolutionary relationships of the three genera are: (Eudiplozoon, (Paradiplozoon, Sindiplozoon)); and of the three suborders: (Discocotylinea, (Microcotylinea, Gastrocotylinea)). These intergeneric relationships were also supported by the skewness and principal component analyses. Our results show that nad2, atp6 and nad6 (fast-evolving) would be better candidates than cox1 (slow-evolving) for species identification and population genetics studies in Diplozoidae. Nucleotide bias and codon and amino acid usage patterns of the three diplozoid mitogenomes are more similar to cestodes and trematodes than to other monogenean flatworms. This unusual mutational bias was reflected in disproportionately long branches in the phylogram. Our study offsets the scarcity of molecular data for the subclass Polyopisthocotylea to some extent, and might provide important new insights into the evolutionary history of the three genera and three suborders.