Marine invertebrates analysis

Ache, B.W., The experimental analysis of host location in symbiotic marine invertebrates, in Symbiosis in the Sea, Vernberg, W.B., Ed., University of South Carolina Press, Columbia, South Carolina, 1972, 45. 

Hadfield, M. G., Metamorphosis in marine molluscan larvae an analysis of stimulus and response, in Settlement and Metamorphosis of Marine Invertebrate Larvae, Chia, F. S. and Rice, M. E., Eds., Elsevier, New York, 1978, 165. 

Marine sponges contain a host of bioactive compounds, particularly small molecules, and also contain a range of peptides that are non-ribosomally synthesised, often containing non-native amino acids. However, there are examples of peptides of ribosomal origin, including, for example, asteropine A isolated from the sponge Asteropus simplex.133 This peptide comprises 36 residues and three disulphide bonds. It has potent sialidase inhibitory activity and thus has applications in the design of novel viral inhibitors. Structural analysis of asteropine A with NMR spectroscopy revealed a cystine-knot motif, similar to that already described for plant toxins. This observation emphasises the fact that the cystine-knot motif is extremely prevalent in disulphide-rich peptides.134 Asteropine A, discovered in 2006, was the first reported cystine-knot peptide isolated from marine invertebrates other than from cone snails, which are described in more detail below. 

Several guanidine-modified tetrapeptides have been isolated from marine invertebrates, in particular marine sponges. Nazumamide A (39) has been isolated from the sponge Theondla sp. and identified by analysis of spectroscopic data [60] as well as by X-ray diffraction analysis of a nazumamide A-human thrombin complex [61[. Nazumamide A has been synthesized by conventional peptide synthesis [62[. A series of nazumamide derivatives have been prepared via combinatorial synthesis [63[. 

Sterols of marine invertebrates have been found to comprise most complex mixtures more than 120 sterols have been isolated and their structures determined [1]. Analysis of these sterols has been performed largely by GC, GC/MS and HPLC. Stereochemical details were determined by NMR or by synthetic work. Fig. 1 demonstrates the effectivity of a capillary colunrn a and b showing the GC analysis of a sterol fraction obtained from the sponge, Hymeniacidon perleve using a packed and a capillary column, respectively [2]. 

A group of tricyclic diterpenoids related to dolatriol has been isolated from the marine invertebrate Clavularia inflata. The structure of the diol (122) was obtained by X-ray analysis and those of (123) and (124) by chemical correlation. 

As part of their ongoing investigation of bioactive natural products from tropical marine invertebrates collected in Sodwana Bay (situated in northern Kwazulu-Natal, South Africa), Kashman and co-workers isolated three novel alkaloids, polycitone A (89) and polycitrins A and B (90 and 91) from an ascidian Polycitor sp. [86]. The structure of 89 was established from X-ray data while the structures of 90 and its mono-O-methyl ether analogue, 91, followed from analysis of the NMR data of these two compounds. Two possible biosynthetic precursors of 89-91,... 

There have been no natural products investigations of soft corals from the cool temperate west coast of southern Africa. Soft corals are common along the south-east coast of South Africa and as part of our ongoing search for bioactive metabolites from the marine invertebrate fauna of the Tsitsikamma Marine Reserve we isolated four bioactive xenicane diterpenes, the tsitsixenicins A - D (93 - 96) from the endemic soft coral Capnella thyrsoidea (Family Nephtheidae) [91]. The structures of 93 -96 were delineated from standard analysis of their NMR data and comparison of these data with those published for related compounds e.g. 9-deacetoxy-14,15-deepoxyxeniculin (diastereomic with 93) isolated from the Red Sea soft coral Xenia macrospiculata [92]. 

Sea whips encompass widely diverse morphologies among soft-bodied marine invertebrates and are readily abundant in reef environments. As documented by Pawlik [4], and Fenical and coworkers [59], this genus of soft corals has fleshy tissues that appear to be physically unprotected from potential predators, yet seem to be unmolested and have only a few predators. Analysis of the wide spectrum of the potent biologically active metabolites of Pseudopterogorgia presented in table 7 may offer a possible explanation of the seemingly few predators of this specie. 

Boron can be extracted from natural or synthetic calcium carbonate (or other geologic materials) before analysis by mass spectrometry. The extraction method depends on the analytical technique to be used. For any method, natural samples (typically foraminifera, a single-celled marine invertebrate whose shells accumulate in ocean sediments) must be cleaned of organic matter. This is... 

Kennard, O., Watson, D.G., Di Sanseverino, L.R., Tiusch, B Bosmans, R., and Djerassi, C. (1968) Chemical studies of marine invertebrates. IV. Terpenoids LXII. Eunicellin, a diterpenoid of the gorgonian Eunicella stricta X-ray diffraction analysis of eimicellin dibromide. Tetrahedron Lett, 9, 2879-2884. 

Butman, C.A., Larval settlement of soft-sediment invertebrates some predictions based on analysis of near-bottom velocity profiles, in Marine Interface Ecohydrodynamics, Nihoul, J.C.J., Ed., Elsevier, Amsterdam, 487, 1986. 

There have been numerous studies examining the selection of data for an SSD. Forbes and Calow (2002) made the point that only a fraction of the species going into the SSD determines the effects threshold. With all species being weighted equally, the loss of any species is of equal importance to the system, while keystone or other important species are assumed to be randomly distributed in the SSD. For example, the ecologically realistic distribution of species by trophic level was 64% primary producers, 26% herbivores (invertebrates), and 10% carnivores (fish), compared to the mean ratio from SSDs for different chemicals of 27.5, 34.7, and 37.8%, respectively. Such variations were shown to alter the SSDs by as much as 10% (Duboudin et al. 2004). A sensitivity analysis performed on available data for chromium (VI) in marine waters (Table 4.8) shows how additional data points, or selective removal of data, have an impact on the derived 5th percentile (HC5). The effects are relatively small but can be higher for the 1st percentile data (HC1). Our view is that, provided the data set includes numbers of sensitive and insensitive species equal to or above the minimum data set, it is considered to be adequate. 

Domoic acid exposure to mammals occurs orally in a matrix of shellfish to human consumers, planktivorous fish and benthic invertebrates to marine mammals, and perhaps zooplankton and chained diatoms to whales. Analysis of the consumed mussels from the 1987 exposure indicated that 1 mg/kg was sufficient to induce gastrointestinal symptoms and 4.5 mg/kg could induce neurological effects in humans (Perl et al. 1990). Experimental studies in monkeys, rats and mice have utilized oral gavage, intraparenteal, and intravenous exposure routes and determined that oral gavage is about ten times less effective that the other routes of exposure (Iverson et al. 1990). Humans appear much more sensitive than either monkeys or rats, which when dosed orally have no observable adverse effect levels (NOAEL) at 5 and 28 mg/kg, respectively. Experimental animals have permitted evaluation of different dose scenarios. A daily NOAEL oral gavage of domoic acid to rats for... 

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