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Fu-lin E. Chu - One of the best experts on this subject based on the ideXlab platform.
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effects of triclosan on growth viability and fatty acid synthesis of the oyster protozoan parasite perkinsus marinus
Diseases of Aquatic Organisms, 2005Co-Authors: Eric D Lund, Fu-lin E. Chu, Philippe Soudant, Ellen Harvey, Stephanie L Bolton, Adolph FlowersAbstract:Perkinsus marinus, a protozoan parasite of the Eastern oyster Crassostrea virginica, has severely impacted oyster populations from the Mid-Atlantic region to the Gulf of Mexico coast of North America for more than 30 yr. Although a chemotherapeutic treatment to reduce or eliminate P. marinus from infected oysters would be useful for research and hatchery operations, an effective and practical drug treatment does not currently exist. In this study, the antimicrobial drug triclosan 5-chloro-2-(2,4 dichlorophenoxy) phenol, a specific inhibitor of Fab1 (enoyl-acyl-carrier-protein reductase), an enzyme in the Type II class of fatty acid synthetases, was tested for its effects on viability, proliferation and fatty acid synthesis of in vitro-cultured P. marinus Meronts. Treatment of P. marinus meront cell cultures with concentrations of > or = 2 microM triclosan at 28 degrees C (a temperature favorable for parasite proliferation) for up to 6 d stopped proliferation of the parasite. Treatment at > or = 5 microM at 28 degrees C greatly reduced the viability and fatty acid synthesis of meront cells. Oyster hemocytes treated with > or = 20 microM triclosan exhibited no significant (p or = 2 microM triclosan for 24 h at 13 degrees C exhibited significantly (p or = 20 microM resulted in > 50% mortality of P. marinus cells after 24 h. These results suggest that triclosan may be effective in treating P. marinus-infected oysters.
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arachidonic acid synthetic pathways of the oyster protozoan parasite perkinsus marinus evidence for usage of a delta 8 pathway
Molecular and Biochemical Parasitology, 2004Co-Authors: Fu-lin E. Chu, Eric D Lund, Ellen Harvey, R O AdlofAbstract:Abstract The meront stage of the oyster protozoan parasite, Perkinsus marinus, is capable of synthesizing saturated and unsaturated fatty acids including the essential fatty acid, arachidonic acid [20:4(n−6)]. Eukaryotes employ either delta-6 (Δ-6) or delta-8 (Δ-8) desaturase pathway or both to synthesize arachidonic acid. To elucidate the arachidonic acid synthetic pathways in P. marinus, Meronts were incubated with deuterium-labeled precursors [18:1(n−9)-d6, 18:2(n−6)-d4, 18:3(n−3)-d4, and 20:3(n−3)-d8]. The lipids were extracted, converted to fatty acid methyl esters, and analyzed using gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. Deuterium-labeled 18:2(n−6), 20:2(n−6), 20:3(n−6), and 20:4(n−6) were detected in meront lipids after 1-, 3-, 5-, and 10-day incubation with 18:1(n−9)-d6. Deuterium-labeled 20:2(n−6), 20:3(n−6) and 20:4(n−6) were found in lipids from Meronts after incubation with 18:2(n−6)-d4 methyl ester. No labeled 18:3(n−6) was detected in either incubation. Apparently, when incubated with 18:1(n−9)-d6, the parasite first desaturated 18:1(n−9)-d6 to 18:2(n−6)-d6 by Δ-12 desaturase, then to 20:2(n−6)-d6 by elongation, and ultimately desaturated to 20:3(n−6)-d6 and 20:4(n−6)-d6 using the sequential Δ-8 and Δ-5 desaturation. Similarly, when incubated with 18:2(n−6)-d4, P. marinus converted the 18:2(n−6)-d4 to 20:2(n−6)-d4 by elongation and 20:2(n−6)-d4 to 20:3(n−6)-d4 by Δ-8 desaturase then by Δ-5 desaturase to 20:4(n−6)-d4. These results provide evidence that P. marinus employed the Δ-8 rather Δ-6 pathway for arachidonic acid synthesis. Additional support for the presence of a Δ-8 pathway was the demonstrated ability of the parasite to metabolize 18:3(n−3)-d4 to 20:3(n−3)-d4 and 20:4(n−3)-d4, and 20:3(n−3)-d8 to 20:4(n−3)-d6 and 20:5(n−3)-d6 using the sequential position-specific Δ-8 and Δ-5 desaturases.
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de novo arachidonic acid synthesis in perkinsus marinus a protozoan parasite of the eastern oyster crassostrea virginica
Molecular and Biochemical Parasitology, 2002Co-Authors: Fu-lin E. Chu, Eric D Lund, Philippe Soudant, Ellen HarveyAbstract:Abstract The capability of synthesizing fatty acids de novo in the meront stage of the oyster protozoan parasite, Perkinsus marinus , was investigated employing stable-isotope-labeled precursors (1,2 13 C-acetate and palmitic-d 31 acid). Fatty acid methyl esters derived from 1,2 13 C-acetate and palmitic-d 31 acid were analyzed using gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. Results revealed that in vitro cultured P. marinus Meronts utilized 13 C-acetate to synthesize a range of saturated and unsaturated fatty acids. The saturated fatty acids 14:0, 16:0, 18:0, 20:0, 22:0, 24:0 and the unsaturated fatty acids, 18:1( n -9), 18:2( n -6), 20:1( n -9), 20:2( n -6), 20:2( n -9), 20:3( n -6), 20:4( n -6) were found to contain 13 C, after 7, 14, and 21 days incubation with the precursor. This indicates that Meronts can synthesize fatty acid de novo using acetate as a substrate. Meronts efficiently elongated 16:0-d 31 to 18:0, 20:0, 22:0, 24:0, but desaturation activity was limited, after 7 and 14 days cultivation. Only a small quantity of 18:1-d 29 was detected. This suggests that Meronts cannot directly convert exogenous palmitic acid or its products of elongation to unsaturated counterparts. The ability to synthesize 20:4( n -6) from acetate is particularly interesting. No parasitic protozoan has been reported to be capable of synthesizing long chain essential fatty acids, such as 20:4( n -6) de novo. Future study will be directed to determine whether the observed in vitro activities indeed reflect the in vivo activities, when Meronts are associated with the host.
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lipid class and fatty acid composition of the protozoan parasite of oysters perkinsus marinus cultivated in two different media
Journal of Eukaryotic Microbiology, 2001Co-Authors: Philippe Soudant, Fu-lin E. ChuAbstract:The meront stage of the oyster protozoan parasite, Perkinsus marinus, cultivated in two media with different fatty acid profiles was analyzed for its fatty acid and lipid class composition. The composition of fatty acids in the prezoosporangium stage of the parasite as well as that of the host oyster were investigated. Although the lipid class composition of Meronts was dominated by phospholipids and triacylglycerol, there was no triaclgycerol detected in either culture medium. Despite the difference in fatty acid composition of the two media, the fatty acid composition of Meronts in each medium was dominated by 14:0, 16:0, 18:0, 18:1(n-9), 20:1(n-9), 18:2(n-6) and 20:4(n-6), a profile that differed from its host. The quantities of total lipids and fatty acids in Meronts increased as the number of Meronts increased and far exceeded the initial amounts in the media and in the initial cell inoculum. The Meronts harvested 25 d post-inoculation, had about 3 to 6 times higher total lipids and 4 to 13 times higher fatty acids than the amounts contained in the media. The fatty acid profiles of both prezoosporangia and oysters resembled each other and consisted primarily of 16:0, 20:4(n- 6), 20:5(n-3), 22:2 D7,15, and 22:6(n-3). These results indicate that during meront proliferation, the parasite synthesizes certain fatty acids and lipid classes. For development from meront to prezoosporangium, the parasite may rely on its host for lipid resources.
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suppression of chemiluminescence of eastern oyster crassostrea virginica hemocytes by the protozoan parasite perkinsus marinus
Developmental and Comparative Immunology, 1995Co-Authors: Aswani K Volety, Fu-lin E. ChuAbstract:Experiments were conducted to determine the ability of the protistan parasite, Perkinsus marinus, to inhibit chemiluminescence of hemocytes from the eastern oyster, Crassostrea virginica. Luminol-enhanced chemiluminescence (CL) was used to measure the production of reactive oxygen intermediates (ROI) generated by oyster hemocytes using zymosan as a stimulant. To determine whether P. marinus suppresses ROI evoked from zymosan-stimulated hemocytes, live or heat killed P. marinus in filtered estuarine water (YRW) (salinity = 20 ppt) were added to (1) zymosan-stimulated hemocytes after CL reached its peak, or (2) hemocytes at the same time as zymosan, and reduction of CL responses were recorded. In both tests, controls received only estuarine water. Live P. marinus Meronts significantly suppressed ROI production by zymosan-stimulated hemocytes. The suppression of ROI production was dose dependent. Suppression of ROI production from zymosan-stimulated hemocytes by heat killed P. marinus was significantly less than by live P. marinus. Similarly, CL of hemocytes was reduced, though not significantly when hemocytes were exposed to YRW preincubated with P. marinus. When P. marinus Meronts were used as a stimulant, no CL response was elicited. Results of this study suggest that P. marinus cells are able to suppress ROI release from oyster hemocytes, thus evading this component of the host's defense.
Panagiotis Karanis - One of the best experts on this subject based on the ideXlab platform.
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electron microscopic observation of the early stages of cryptosporidium parvum asexual multiplication and development in in vitro axenic culture
European Journal of Protistology, 2016Co-Authors: Hebatalla M Aldeyarbi, Panagiotis KaranisAbstract:Abstract The stages of Cryptosporidium parvum asexual exogenous development were investigated at high ultra-structural resolution in cell-free culture using transmission electron microscopy (TEM). Early C. parvum trophozoites were ovoid in shape, 1.07 × 1.47 μm2 in size, and contained a large nucleus and adjacent Golgi complex. Dividing and mature Meronts containing four to eight developing merozoites, 2.34 × 2.7 μm2 in size, were observed within the first 24 h of cultivation. An obvious peculiarity was found within the merozoite pellicle, as it was composed of the outer plasma membrane with underlying middle and inner membrane complexes. Further novel findings were vacuolization of the meront's residuum and extension of its outer pellicle, as parasitophorous vacuole-like membranes were also evident. The asexual reproduction of C. parvum was consistent with the developmental pattern of both eimerian coccidia and Arthrogregarinida (formerly Neogregarinida). The unique cell-free development of C. parvum described here, along with the establishment of Meronts and merozoite formation, is the first such evidence obtained from in vitro cell-free culture at the ultrastructural level.
Philippe Soudant - One of the best experts on this subject based on the ideXlab platform.
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effects of triclosan on growth viability and fatty acid synthesis of the oyster protozoan parasite perkinsus marinus
Diseases of Aquatic Organisms, 2005Co-Authors: Eric D Lund, Fu-lin E. Chu, Philippe Soudant, Ellen Harvey, Stephanie L Bolton, Adolph FlowersAbstract:Perkinsus marinus, a protozoan parasite of the Eastern oyster Crassostrea virginica, has severely impacted oyster populations from the Mid-Atlantic region to the Gulf of Mexico coast of North America for more than 30 yr. Although a chemotherapeutic treatment to reduce or eliminate P. marinus from infected oysters would be useful for research and hatchery operations, an effective and practical drug treatment does not currently exist. In this study, the antimicrobial drug triclosan 5-chloro-2-(2,4 dichlorophenoxy) phenol, a specific inhibitor of Fab1 (enoyl-acyl-carrier-protein reductase), an enzyme in the Type II class of fatty acid synthetases, was tested for its effects on viability, proliferation and fatty acid synthesis of in vitro-cultured P. marinus Meronts. Treatment of P. marinus meront cell cultures with concentrations of > or = 2 microM triclosan at 28 degrees C (a temperature favorable for parasite proliferation) for up to 6 d stopped proliferation of the parasite. Treatment at > or = 5 microM at 28 degrees C greatly reduced the viability and fatty acid synthesis of meront cells. Oyster hemocytes treated with > or = 20 microM triclosan exhibited no significant (p or = 2 microM triclosan for 24 h at 13 degrees C exhibited significantly (p or = 20 microM resulted in > 50% mortality of P. marinus cells after 24 h. These results suggest that triclosan may be effective in treating P. marinus-infected oysters.
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de novo arachidonic acid synthesis in perkinsus marinus a protozoan parasite of the eastern oyster crassostrea virginica
Molecular and Biochemical Parasitology, 2002Co-Authors: Fu-lin E. Chu, Eric D Lund, Philippe Soudant, Ellen HarveyAbstract:Abstract The capability of synthesizing fatty acids de novo in the meront stage of the oyster protozoan parasite, Perkinsus marinus , was investigated employing stable-isotope-labeled precursors (1,2 13 C-acetate and palmitic-d 31 acid). Fatty acid methyl esters derived from 1,2 13 C-acetate and palmitic-d 31 acid were analyzed using gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. Results revealed that in vitro cultured P. marinus Meronts utilized 13 C-acetate to synthesize a range of saturated and unsaturated fatty acids. The saturated fatty acids 14:0, 16:0, 18:0, 20:0, 22:0, 24:0 and the unsaturated fatty acids, 18:1( n -9), 18:2( n -6), 20:1( n -9), 20:2( n -6), 20:2( n -9), 20:3( n -6), 20:4( n -6) were found to contain 13 C, after 7, 14, and 21 days incubation with the precursor. This indicates that Meronts can synthesize fatty acid de novo using acetate as a substrate. Meronts efficiently elongated 16:0-d 31 to 18:0, 20:0, 22:0, 24:0, but desaturation activity was limited, after 7 and 14 days cultivation. Only a small quantity of 18:1-d 29 was detected. This suggests that Meronts cannot directly convert exogenous palmitic acid or its products of elongation to unsaturated counterparts. The ability to synthesize 20:4( n -6) from acetate is particularly interesting. No parasitic protozoan has been reported to be capable of synthesizing long chain essential fatty acids, such as 20:4( n -6) de novo. Future study will be directed to determine whether the observed in vitro activities indeed reflect the in vivo activities, when Meronts are associated with the host.
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lipid class and fatty acid composition of the protozoan parasite of oysters perkinsus marinus cultivated in two different media
Journal of Eukaryotic Microbiology, 2001Co-Authors: Philippe Soudant, Fu-lin E. ChuAbstract:The meront stage of the oyster protozoan parasite, Perkinsus marinus, cultivated in two media with different fatty acid profiles was analyzed for its fatty acid and lipid class composition. The composition of fatty acids in the prezoosporangium stage of the parasite as well as that of the host oyster were investigated. Although the lipid class composition of Meronts was dominated by phospholipids and triacylglycerol, there was no triaclgycerol detected in either culture medium. Despite the difference in fatty acid composition of the two media, the fatty acid composition of Meronts in each medium was dominated by 14:0, 16:0, 18:0, 18:1(n-9), 20:1(n-9), 18:2(n-6) and 20:4(n-6), a profile that differed from its host. The quantities of total lipids and fatty acids in Meronts increased as the number of Meronts increased and far exceeded the initial amounts in the media and in the initial cell inoculum. The Meronts harvested 25 d post-inoculation, had about 3 to 6 times higher total lipids and 4 to 13 times higher fatty acids than the amounts contained in the media. The fatty acid profiles of both prezoosporangia and oysters resembled each other and consisted primarily of 16:0, 20:4(n- 6), 20:5(n-3), 22:2 D7,15, and 22:6(n-3). These results indicate that during meront proliferation, the parasite synthesizes certain fatty acids and lipid classes. For development from meront to prezoosporangium, the parasite may rely on its host for lipid resources.
Yuliya Y Sokolova - One of the best experts on this subject based on the ideXlab platform.
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a new microsporidium apotaspora heleios n g n sp from the riverine grass shrimp palaemonetes paludosus decapoda caridea palaemonidae
Journal of Invertebrate Pathology, 2018Co-Authors: Yuliya Y Sokolova, Robin M OverstreetAbstract:Abstract We report a new microsporidium from a key species of the estuarine communities of the Gulf States, the Riverine grass shrimp, Palaemonetes paludosus. A milky-white shrimp was found in the Mobile Bay Delta, a large, oligohaline-freshwater wetland in Alabama, USA. Light microscopy of smears and thick sections of the abdominal tissues demonstrated infection with microsporidian spores enclosed in sporophorous vesicles (SVs) in sets of eight. Broadly oval spores measured 2.9 ± 0.06 × 1.7 ± 0.03 µm (2.5–3.3 × 1.6–1.9 µm, n = 11). SVs with a persistent membrane ranged from 4.4 to 5.6 µm in diameter. Subcuticular epithelium and underlying musculature were packed with sporonts, sporoblasts, and spores. Electron microscopy demonstrated diplokaryotic Meronts that gave rise to sporont mother cells with a large single nucleus. The meront plasma membrane turned into a SV envelope, and the sporont wall segregated internally. The sporont nucleus underwent meiosis followed by two mitotic divisions accompanied by internal budding to produce four sporonts, each dividing in two uninucleate sporoblasts. Eight-spore SVs were filled with fibrillary-tubular secretions. Spores possessed 90–110-nm thick envelopes (exospore, 40–60 nm + endospore, 30–50 nm), a triangle-shaped nucleus, isofilar polar filament of 10–13 coils arranged in two-three rows, bipartite polaroplast, and a mushroom-shaped polar disk. The SSU rDNA sequence of the novel species was deposited in GenBank under Accession number MG 708238. SSU rDNA-based phylogenetic analysis indicated that the Riverine grass shrimp microsporidium was a new species and placed it in one branch with two species of Potaspora, xenoma-forming microsporidia from freshwater perciform fishes. Because morphological and developmental characters of the novel species did not fit the diagnosis of the genus Potaspora, and, based on SSU rDNA-inferred phylogenetic analyses, different host specificity, pathogenesis, and ecological considerations, we erect here the new genus Apotaspora for the Riverine grass shrimp microsporidium and name the new species Apotaspora heleios. Grouping together fish and crustacean parasites on SSU rDNA phylogenetic trees suggests that polyxenous life cycles might be a common feature of extinct and/or extant members of the studied lineage of the Microsporidia.
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an ultrastructural study of nosema locustae canning microsporidia from three species of acrididae orthoptera
Acta Protozoologica, 2002Co-Authors: Yuliya Y Sokolova, Carlos E LangeAbstract:Summary. Nosema locustae is a pathogen of orthopterans with an unusually wide host range. It is the only microsporidian that has been developed as a microbial control agent. In spite of its practical importance the ultrastructure of N. locustae life stages other than spores, has not been studied. The insects used in this study, all in the family Acrididae, were the Migratory locust, Locusta migratoria migratorioides (Oedipodinae), the South American locust, Schistocerca cancellata (Cyrtacanthacridinae), and the grasshopper Dichroplus schulzi (Melanoplinae). All insects were reared routinely in the laboratory. The spores of N. locustae used for the experimental peroral inoculations were all of North American origin. Fat body cells were the predominant site of parasite development, though infection of tracheal epithelium cells and haemocytes also occurred. Ultrastructure of Meronts, sporonts, sporoblasts and spores is described. The fine morphology of N. locustae stages is typical for microsporidians of the genus Nosema. Nuclei were always in diplokaryotic arrangement. Transition from meront to sporont was characterized by striking changes in parasite ultrastructure: appearance of electron dense granules (50-100 nm in diameter, presumable RNP complexes) in the nucleoplasm, and stacks of ER cisternae and prominent vacuoles in cytoplasm. The beginning of sporogony was marked by an increase in size of parasite cells due to extensive vacuolization. Tubule-like structures appeared in the host cell cytoplasm during parasite sporogony. Elongated conglomerates of electron dense material were scattered in the host cell and eventually ornamented the outersurface of the parasite membrane, forming an electron dense layer around sporonts. Spores were diplokaryotic, measured 4.95 ‐ 0.07 x 2.65 ‐ 0.04 µm (mean ‐ SE, n=24) on fresh smears and 3.49 ‐ 0.18 x 1.73 ‐ 0.04 µm (n = 10) on ultrathin sections, and had electron-dense cytoplasm in which all internal structures typical of microsporidian spores were recognizable. The polaroplast was lamellar, the endospore was 200-300 nm thick, and the exospore was 40-50 nm. The polar filament was isofilar, arranged in 17-18 coils. Our study did not reveal any difference in the morphology of N. locustae while developing in the three different hosts.
Robin M Overstreet - One of the best experts on this subject based on the ideXlab platform.
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a new microsporidium apotaspora heleios n g n sp from the riverine grass shrimp palaemonetes paludosus decapoda caridea palaemonidae
Journal of Invertebrate Pathology, 2018Co-Authors: Yuliya Y Sokolova, Robin M OverstreetAbstract:Abstract We report a new microsporidium from a key species of the estuarine communities of the Gulf States, the Riverine grass shrimp, Palaemonetes paludosus. A milky-white shrimp was found in the Mobile Bay Delta, a large, oligohaline-freshwater wetland in Alabama, USA. Light microscopy of smears and thick sections of the abdominal tissues demonstrated infection with microsporidian spores enclosed in sporophorous vesicles (SVs) in sets of eight. Broadly oval spores measured 2.9 ± 0.06 × 1.7 ± 0.03 µm (2.5–3.3 × 1.6–1.9 µm, n = 11). SVs with a persistent membrane ranged from 4.4 to 5.6 µm in diameter. Subcuticular epithelium and underlying musculature were packed with sporonts, sporoblasts, and spores. Electron microscopy demonstrated diplokaryotic Meronts that gave rise to sporont mother cells with a large single nucleus. The meront plasma membrane turned into a SV envelope, and the sporont wall segregated internally. The sporont nucleus underwent meiosis followed by two mitotic divisions accompanied by internal budding to produce four sporonts, each dividing in two uninucleate sporoblasts. Eight-spore SVs were filled with fibrillary-tubular secretions. Spores possessed 90–110-nm thick envelopes (exospore, 40–60 nm + endospore, 30–50 nm), a triangle-shaped nucleus, isofilar polar filament of 10–13 coils arranged in two-three rows, bipartite polaroplast, and a mushroom-shaped polar disk. The SSU rDNA sequence of the novel species was deposited in GenBank under Accession number MG 708238. SSU rDNA-based phylogenetic analysis indicated that the Riverine grass shrimp microsporidium was a new species and placed it in one branch with two species of Potaspora, xenoma-forming microsporidia from freshwater perciform fishes. Because morphological and developmental characters of the novel species did not fit the diagnosis of the genus Potaspora, and, based on SSU rDNA-inferred phylogenetic analyses, different host specificity, pathogenesis, and ecological considerations, we erect here the new genus Apotaspora for the Riverine grass shrimp microsporidium and name the new species Apotaspora heleios. Grouping together fish and crustacean parasites on SSU rDNA phylogenetic trees suggests that polyxenous life cycles might be a common feature of extinct and/or extant members of the studied lineage of the Microsporidia.