12 resultados para Javanicus


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Vit het Tijdschrift voor Nat. gesch. en physiol. VIIIste deel ...

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Caribbean ciguatoxins (C-CTXs) are responsible for the widespread occurrence of ciguatera in the Caribbean Sea. The structure and configuration of C-CTX-1 (1), the major ciguatoxin isolated from the horse-eye jack (Caranx latus), has been determined from DQF-COSY, E-COSY, TOCSY, NOESY, POESY, ge-HSQC. and HMQC experiments performed at 750 MHz and 500 MHz on a 0.13 pmol sample. C-CTX-1 ([M + H](+) m/z 1141.6 Da, molecular formula C62H92O19) has a ciguatoxin/breveroxin ladder structure comprising 14 trans-fused, ether-linked rings (7/6/6/7/8/9/7/6/8/6/7/6/7/6) assembled fi um 6 protonated fragments. The relative stereochemistry and ring configuration of 1 was determined from an analysis of coupling constant and NOE data. Like ciguatoxins in the Pacific Ocean (P-CTX), C-CTX-1 possesses a flexible nine-membered ring which may be a conserved feature among ciguatoxins. However, C-CTX-1 has a longer contiguous carbon backbone (57 vs 55 carbons for P-CTX-1), one extra ring, and a hemiketal in ring N but no spiroketal as found in P-CTX. C-CTX-1 possesses a primary hydroxyl which may allow selective derivatization. A minor analogue, C-CTX-2, was also isolated from fish and assigned the structure 56 epi-C-CTX-1 (2). since it slowly rearranged to C-CTX-1 in solution. Given the structural similarities between Caribbean and Pacific ciguatoxins, we propose that C-CTX-1 and C-CTX-2 arise from a Caribbean strain of the benthic dinoflagellate, Gambierdiscus toxicus.

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Ciguatera is a global disease caused by the consumption of certain warm-water fish (ciguateric fish) that have accumulated orally effective levels of sodium channel activator toxins (ciguatoxins) through the marine food chain. Symptoms of ciguatera include a range of gastrointestinal, neurological and cardiovascular disturbances. This review examines progress in our understanding of ciguatera from the work of Banner in the late 1950s to the present. Similarities and differences in ciguatera in the Pacific Ocean, Indian Ocean and Caribbean Sea are highlighted, and future research directions are suggested. (C) 2000 Elsevier Science Ltd. All rights reserved.

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Jembrana disease virus (JDV) is a newly isolated and characterised bovine lentivirus. It causes an acute disease in Ball cattle (Bos javanicus). which can be readily transmitted to susceptible cattle with 17% mortality. There is as yet no treatment or preventive vaccine. We have developed a gene transfer vector system based on JDV that has three components. The first of the components is a bicistronic transfer vector plasmid that was constructed to contain cis-sequences from the JDV genome, including 5 '- and 3 ' -long terminal repeats (LTRs), 0.4 kb of truncated gag and 1.1 kb of 3 ' -env, a multiple cloning site to accommodate the gene(s) of interest for transfer, and an internal ribosome entry site plus the neomycin phosphotransferase (Neo) gene cassette for antibiotic selection. The second element is a packaging plasmid that contains trans-sequences. including gag, pol. vif, tar and rev: but without the env and packaging signals. The third is a plasmid encoding the G glycoprotein of vesicular stomatitis virus (VSV-G) to supply the vector an envelope for pseudotyping. Cotransfection of 293T cells with these three plasmid components produced VSV-G pseudotyped. disabled, replication defective, bicistronic JDV vectors encoding the green fluorescent protein (EGFP) and the Neo resistance selection maker simultaneously with a titre range of (0.4-1.2) x 10(6) CFU/ml. Transduction of several replicating primary and transformed cells from cattle, primate and human sources and importantly growth-arrested cells with the JDV vectors showed high efficiency of EGFP gene transfer at 35-75%, which was stable and the expression of EGFP was long term. Furthermore, these JDV vectors were designed to suit the inclusion and expression of genes corresponding to JDV specific proteins, such as gag or env, for the development of vaccines for Jembrana disease. This strategy should also be applicable to other bovine diseases as wall. The design and construction of the JDV vector system should facilitate the study of the lentivirology and pathogenesis of the diseases associated with JDV or other bovine virus infections. To our knowledge, this is the first such vector system developed from a cattle virus. (C) 2001 Elsevier Science B.V. All rights reserved.

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Optimised gradient reversed-phase high-performance liquid chromatography electrospray ionisation mass spectrometry (LC/MS) methods, in combination with a [H-3]-brevetoxin binding assay (RLB), revealed multiple ciguatoxins in a partially purified extract of a highly toxic Lutjanus sebae (red emperor) from the Indian Ocean. Two major ciguatoxins of 1140.6 Da (I-CTX-1 and -2) and two minor ciguatoxins of 1156.6 Da (I-CTX-3 and -4) were identified. Accurate mass analysis revealed that I-CTX-1 and -2 and Caribbean C-CTX-1 had indistinguishable masses (1140.6316 Da, at 0.44 ppm resolution). Toxicity estimated from LC/MS/RLB responses indicated that I-CTX-1 and -2 were both similar to 60% the potency of Pacific ciguatoxin-1 (P-CTX-1). In contrast to ciguatoxins of the Pacific where the more oxidised ciguatoxins are more potent, I-CTX-3 and -4 were similar to 20% of P-CTX-1 potency. Interconversion in dilute acid or on storage, typical of spiroketal and hemiketal functionality found in P-CTXs and C-CTXs, respectively, was not observed to occur between I-CTX-1 and -2. The ratio of CTX-1 and -2 varied depending on the fish extract being analysed. These results suggest that I-CTX-1 and -2 may arise from separate dinoflagellate precursors that may be oxidatively biotransformed to I-CTX-3 and -4 in fish. (C) 2002 Published by Elsevier Science Ltd.

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We report the isolation and initial characterisation of Indian Ocean ciguatoxin (I-CTX) present in toxic lipid soluble extracts isolated from ciguateric fishes collected off the Republic of Mauritius in the Indian Ocean. Following i.p. injection of this extract, mice displayed symptoms that were similar, though not identical, to those produced by Pacific and Caribbean ciguatoxins (P-CTXs and C-CTXs). Using a radiolabelled brevetoxin (PbTx) binding assay and mouse bioassay guided fractionation, I-CTX was purified by Florisil, Sephadex LH-20 and TSK HW-40S chromatography with good recovery. Isolation to purity was not possible by preparative reversed phase high-performance liquid chromatography (HPLC) due to significant losses of toxicity. However, analytical reversed phase HPLC coupled to an electrospray mass spectrometry detector identified a [M + H](+) ion at m/z 1141.58 which co-eluted with activity that displaced [3 H]-PbTx binding to rat brain. This mass corresponded to C-CTX-1, but the fragmentation pattern of I-CTX showed a different ratio of pseudo molecular and product ions. I-CTX was found to elute later than P-CTX-1 but was practically indistinguishable from C-CTX-1 on reversed phase HPLC, while the TSK HW-40S column chromatography differentiated I-CTX from the later eluting C-CTX-1. Taken together, these results indicate that I-CTX is a new ciguatoxin (CTX) responsible for ciguatera caused by reef fish in the Indian Ocean. (C) 2002 Elsevier Science Ltd. All rights reserved.

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We studied the variation in toxin profiles of purified extracts of 10 individual specimens and two pools of ciguateric Caranx latus. High-performance liquid chromatography/mass spectrometry (HPLC/MS) identified in all individual samples at least seven Caribbean ciguatoxins (C-CTXs) comprising C-CTX-1 and its epimer C-CTX-2 ([M + H](+) m/z 1141.58), and five new C-CTX congeners with pseudo-molecular ions at m/z 1141.58, 1143.60, 1157.57, 1159.58, and 1127.57. In some samples, additional C-CTX isomers were detected with [M + H](+) ions at m/z 1141.58 (two), 1143.60 (one) and 1157.57 (two). The two low-toxic pools contained only four to six ciguatoxins. The comparison in relative proportions of four different mass classes ([M + H](+) at m/z 1141, 1143, 1157 and 1127) showed that the group at m/z 1157 increased (2-20%) with flesh toxicity. More than 80% of group m/z 1141 comprised C-CTX-1, C-CTX-2 and their isomer C-CTX-1 a whose level in this group correlated with fish toxicity. Contrary to low-toxic fishes, high-risk specimens had C-CTX-1 levels

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A grey snapper (Lutjanus griseus), a grouper (Serranidae) and a blackjack (Caranx lugubris) were implicated in three different ciguatera poisonings in Guadeloupe, French West Indies. A mouse bioassay indicated toxicity for each specimens: 0.5-1, greater than or equal to 1 and > 1 M Ug g(-1), respectively. After purification by gel filtration chromatography, the samples were analysed by high-performance liquid chromatography coupled to mass spectrometry (LC-MS). The toxin profiles differ from one fish to another. C-CTX-1 was detected at 0.24, 0.90 and 13.8 ng g(-1) flesh in the snapper, grouper and jack, respectively. It contributed only to part of the whole toxicity determined by the mouse bioassay. Other toxins identified were C-CTX-2 (a C-CTX-1 epimer), three additional isomers of C-CTX-1 or -2, and five ciguatoxin congeners (C-CTX-1127, C-CTX-1143 and its isomer C-CTX-1143a, and C-CTX-1157 and its isomer C-CTX-1157b). Putative hydroxy-polyether-like compounds were also detected in the flesh of the grouper with [M+ + H](+) ions at m/z 851.51, 857.50, 875.51, 875.49 and 895.54 Da. Some of these compounds have the same mass range as some known dinoflagellate toxins. In conclusion, this study confirms the usefulness of LC-MS analysis to determine the ciguatoxins levels and the toxin profile in fish flesh hazardous to humans.

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Vol. 3-5, "Auf grund des nachlasses fortgeführt von A.A.W. Hubrecht ... H. Strahl ... und F. Keibel."

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Ciguatera is a global disease caused by the consumption of certain warm-water fish that have accumulated orally effective levels of sodium channel activator toxins (ciguatoxins) through the marine food chain. Symptoms of ciguatera arising from the consumption of ciguateric fish include a range of gastrointestinal, neurological and cardiovascular disturbances. This review examines progress in our understanding of ciguatera from an Australian perspective, especially the laboratory-based research into the problem that was initiated by the late "Bob" Endean at the University of Queensland.