Toxins from the box-jellyfish Chironex fleckeri

Two myotoxins (T1 and T2) with mol. wts of approximately 600,000 and 150,000, respectively, and a haemolysin (T3) with a mol. wt of approximately 70,000 were isolated from the crude nematocyst venom of C. fleckeri by the use of Sephadex G-200 chromatography. A neurotoxic fraction (T4) and a haemolytic fraction (T5) containing proteins with apparent mol. wts of approximately 150,000 and 70,000, respectively, were also isolated by Sephadex chromatography from crude extracts of tentacular material from which nematocysts had been removed. The three nematocyst toxins and the two toxic fractions from tentacle extracts were lethal to mice on i.v. injection. After SDS-PAGE the myotoxins T1 and T2 yielded similar major bands corresponding with mol. wts different from those yielded by T3 and the toxic tentacle fractions. T1 and T2 appeared to be comprised of aggregations of subunits with mol. wts of approximately 18,000. On HPLC, crude nematocyst venom and the nematocyst toxins T1 and T2 lost their myotoxic properties. The need for thorough removal of extraneous tentacular material from isolated nematocysts, the need for effective rupture of nematocysts, the need to counter the lability of the nematocyst venom and the need to use myotoxicity as a criterion of venom activity if the active components of the venom are to be purified and characterized are emphasized

Apparent relationships between toxins elaborated by the cyanobacterium Trichodesmium erythraeum and those present in the flesh of the narrow-barred Spanish mackerel Scomberomorus commersoni

R. Endean, S. A. Monks, J. K. Griffith and L. E. Llewellyn. Apparent relationships between toxins elaborated by the cyanobacterium Trichodesmium erythraeum and those present in the flesh of the narrow-barred Spanish mackerel Scomberomorus commersoni. Toxicon 31, 1155-1165, 1993.-The marine cyanobacterium Trichodesmium erythraeum contains toxic water-soluble material that produces signs in mice similar to those produced by water-soluble extracts of the flesh of a specimen of pelagic fish Scomberomorus commersoni from a batch that had been implicated in a poisoning resembling ciguatera. Extracts of water-soluble material from both the cyanobacterium and the fish contained toxins that were chromatographically indistinguishable. A peptide and an alkaloid were detected in partially purified extracts of the water-soluble material. In addition to this material toxic lipid-soluble material was present in some batches of T. erythraeum. Elution of this material with 9:1 chloroform: methanol using column chromatography produced material that was chromatographically indistinguishable from ciguatoxin-like material from S. commersoni and produced signs in mice similar to those produced by this material. Elution of the lipid-soluble material with 97:3 chloroform: methanol yielded a toxin resembling in its chromatographic and toxic properties a scaritoxin-like substance from S. commersoni. Other toxins with Rf values lying between that of the ciguatoxin-like material and that of the scaritoxin-like material were also detected in extracts of T. erythraeum. It is postulated that T. erythraeum is the progenitor of major toxins carried by some ciguateric fish and that water-soluble toxins released into the ambient sea water by T. erythraeum may constitute a health hazard for humans

Variation in the toxins present in ciguateric narrow-barred Spanish mackerel, Scomberomorus commersoni

R. Endean, J. K. Griffith, J. J. Robins, L. E. Llewellyn and S. A. Monks. Variation in the toxins present in ciguateric narrow-barred Spanish mackerel, Scomberomorus commersoni. Toxicon 31, 723-732, 1993.-Water-soluble and lipid-soluble toxins present in six specimens of Scomberomorus commersoni captured in subtropical Queensland were compared with those detected in a specimen studied earlier. All specimens were from batches that had been involved in human poisonings. All specimens contained significant amounts of potent water-soluble toxins, the most important of which in terms of contribution to the lethal potency of fish flesh was unidentified toxic material which tested positively for alkaloids. All specimens contained lipid-soluble toxins including ciguatoxin-like and scaritoxin-like material, the latter usually predominating. Amounts of water-soluble toxins with lethal potencies ranging from 14.9 MU to 115 MU/100 g of flesh and of lipid-soluble toxins with lethal potencies ranging from 8.8 MU to 39.9 MU/100 g of flesh were found. (A mouse unit, MU, is the minimum amount of toxic material expressed in g required to kill a 20 g mouse within 24 hr following i.p. injection.) The lethal potency of water-soluble toxins per g of fish exceeded that of lipid-soluble toxins per g of fish for five of the seven specimens of S. commersoni now investigated. Based on a lethal dose to humans of 2500 MU all fishes contained lethal amounts of toxic material. The relative amounts of water-soluble and lipid-soluble toxins present in the flesh of a specimen of S. commersoni were altered by different cooking procedures

Long-range transport of ozone and related pollutants over the North Atlantic in spring and summer

This paper presents strong experimental evidence for a major perturbation in ozone concentrations over large parts of the North Atlantic Ocean from the surface to 8 km associated with continental pollutants. The evidence was gathered in the course of 7 flights by the UK Meteorological Office C-130 aircraft based on the Azores, and 4 ferry flights between the UK to the Azores in spring and summer 1997 as a component of the NERC-funded ACSOE project. The total latitude range covered was approximately 55°N–25°N, and the longitude range was approximately 0° to 40°W. Many profiles were made between the sea surface and altitudes up to 9km to survey the composition of the marine atmosphere. The C-130 aircraft was comprehensively equipped to measure many chemical and physical parameters along with standard meteorological instrumentation. Thus it was able to measure ozone and speciated NOy, along with tracers including water vapour, carbon monoxide and condensation nuclei, in near real time. The overall ‘picture’ of the troposphere over large parts of the North Atlantic is of layers of pollution from the continents of different ages interspersed with layers of air uplifted from the marine boundary layer. The lowest ozone concentrations were recorded in the marine boundary layer where there is evidence for extensive ozone destruction in summer. Flights were made to penetrate the outflow of hurricane Erica, to determine the southerly extent of polluted air in summer, to examine the impact of frontal systems on the composition of remote marine air, and to trace long-range pollution from the west coast of the USA interspersed with air with a stratospheric origin. In one of the spring flights it is possible that a plume of polluted air with high ozone and NOy, and with an origin in southeast Asia, was intercepted off the coast of Portugal. The concentrations of NOx in this plume were sufficient for ozone formation to be continuing along its track from west to east. The instrument to measure NOy almost certainly was only measuring the sum of organic nitrates (mostly in the form of PAN) plus NOx. The high correlation between NOy and ozone under these conditions strongly suggests a non-stratospheric source for most of the ozone encountered over large parts of the atmosphere upwind of Europe. There was a marked seasonal variation in the NOy with about twice as much present in the spring flights than in the summer flights. The overall ozone levels in both spring and summer were somewhat similar although the highest ozone concentration encountered ~100 ppbv) was observed in summer in some polluted layers in mid Atlantic with an origin in the boundary layer over the southeastern USA. The bulk of the pollutants, ozone, CO, and NOy, were in the free troposphere at altitudes between 3 and 8 km. The only instances of pollution at lower levels were in the form of ship plumes, which were encountered several times. The data therefore strongly support the need for more in-situ aircraft experiments to quantify and understand the phenomenon of long-range transport of pollution from continent to continent. Observations at ground-based stations are inadequate for this purpose and satellite data is incomplete both in terms of its altitude detail and in the extent of chemical speciation, particularly for ascertaining whether chemical production and destruction processes for ozone are occurring