Freshwater sponges

A freshwater sponge (Ephydatia fluviatilis) grew normally at a concentration of 0.65 pg Zn/L, but growth was reduced at lower concentrations tested (Francis and Harrison 1988). Daphnids (Daphnia pulex, Daphnia magna) reared for six brood cycles in zinc-free water showed reduced survival, inhibited reproduction, and cuticle damage (Keating and Caffrey 1989). Zinc is important... 

Zinc deficiency effects have been produced experimentally in freshwater sponges at <0.65 pg Zn/L (Francis and Harrison 1988), in rainbow trout fed diets containing <15 mg Zn/kg FW (Spry et al. 1988), in certain species of marine algae at <0.7 pg Zn/L (Vymazal 1986), and in certain species of marine invertebrates at <6.5 pg Zn/L (Clapper et al. 1985a, 1985b) or <34 mg Zn/kg DW whole organism (White and Rainbow 1985). Zinc deficiency in natural aquatic ecosystems has not yet been credibly documented. 

G. Imsiecke, J. Miinkner, B. Lorenz, N. Bachinski, W. G. E. Muller and H. C. Schroder (1996). Inorganic polyphosphate in the developing of the freshwater sponge Ephydatia muelleri effect of stress by polluted waters. Envin. Toxicol. Chem., 15, 1329-1334. 

Simpson, T.L. and Vaccaro, C.A., 1974. An ultrastructural study of silica deposition in the freshwater sponge Spongilla lacustris. J. Ultrastruct. Res., 47 296—309. 

In 2006, Rezanka etal44 isolated an antifeedant, syriacin (59), from the freshwater sponge Ephydatia syriaca in the Jordan river. It is an unusual sulfated ceramide glycoside with branched-chain sphingosine and also a branched-chain fatty acid. From the viewpoint of absolute configuration, 59 is very unusual, because it contains both (if)- and (.V)-configured. rcc-butyl terminals in its alkyl chains. It seems to be biosynthesized from precursors with opposite absolute configuration. 

Silica concentrations are summarized in Table 7.5 for a variety of natural waters. Diatoms can lower lake silica levels to below 3 ppm and to as low as 0.5 to 0.8 ppm (Hutchinson 1957). Some freshwater sponges can reduce lake silica values to 1.2 ppm. 

This chapter describes typical sponge metabolites according to the biosynthetic classification, with references to their important roles in drug discovery as well as in marine ecosystems. To avoid duplication, those compounds described in Comprehensive Natural Products Chemistry are not described in detail here. We do not deal with freshwater sponges, from which only lipids and steroids were reported, except for okadaic acid from the Baikalian sponge Lubomirskia baicalensis ... 

At low concentrations, Ge mimics the metabolic pathway of silicon, whereas at high concentrations it inhibits silicon transport by acting as a classical competitive inhibitor. This is true for all creatures for which silicon is essential or that need silifi-cation. In freshwater sponges, Ge acid (1-25 pg mL ) disrupts spirula formation (Simpson et al. 1983). Ge has also been shown to be toxic to marine gastropods (Rin-kevich 1986). It may also have an antimicrobial effect, with bacteria being more tolerant than yeast (Slawson et al. 1992). 

Simpson TL, Garrone R and Mazzohana M (1983) Interaction of germanium (Ge) with biosilification in the freshwater sponge Ephydatia mulleri evidence of localized membrane domains in the silicalemma. 

Following earlier reports, the reaction was examined by a Russian group (27,28). More recently, the same group have used iodolactonization to identify new A4 and A5 acids in the freshwater sponge Baicalospongia baciliferai (30). 

Imbs, A.B., and N. A. Latyshev, New A4 and A5 Unsaturated Medium- and Long-Chain Fatty Acids in the Freshwater Sponge Baicalospogia bacilifera, Chem. Phys. Lipids, 92 117-125 (1998). 

Imsiecke, G., Muller, W.E.G., 1995. Unusual presence and intranuclear storage of silica crystals in the freshwater sponges Ephydatia muelleri and Spongilla lacustris (Porifera ... 

This suborder contains all freshwater sponges. Apart from work on the lipids of species found in Lake Baikal, chemists have curiously neglected freshwater... 

Three freshwater sponges harvested at shallow depths (between 3 and 11m) in Lake Baikal highlighted a complete new set of 14 adds formed by an isoprenic moiety and a linear part mono- and polyunsatuted at 5, 5,9, 5,9,17 and 5,9,19 vdth 18-26 carbon atoms. These adds derive either from 5,9,13-trimethyltetradecanoic or phytanic add and have been found only in trace amounts 0.005-0.23% of the total acid fradion (Rezanka and Dembitsky, 1993). 

The order Haplosclerida is particularly important because of both the very high number of publications and published structures, and the fact that each of the six families of marine sponges that belong to this order has overall attracted a similar level of interest from chemists. The order Haplosclerida also includes almost all the freshwater sponges, which are divided into three families (Table 19.6). The six families of marine sponges (Callyspongiidae,... 

Species of the family Spongillidae have been studied the most, and a comprehensive review of their lipids has been published (Dembitsky, 2003). Broadly speaking, there are no significant differences in membrane fatty acids between marine and freshwater sponges, which also contain many branched acids (iso, anteiso, prenylated chains acids) and long-chain demospongic acids with the 5,9 diunsaturation pattern (see above). 

The freshwater sponges are much less prevalent than marine sponges. Almost all known species belong to the order Haplosclerida, suborder Spongillina, and are divided into many families, including Lubomirskiidae... 

The presence of 5,9-26 2 and 5,9,19-26 3 acids in the marine sponge Microciona prolifera and in the freshwater species Ephydatiajluviatilis has allowed the identification of two different pathways for their biosynthesis. In the marine species, 5,9,19-26 3 is formed from exogenous palmitoleic acid (9-16 Ijbyhomologationandsubsequentdesaturation at 5 and 9, but in the freshwater sponge the formation of 5,9,19-26 3 from 5,9-26 2 involves a 19-desaturase identified for the first time in a living organi sm (Hahn et al., 1989). 

Phylogenetic studies based on 18S rRNA showed that all freshwater sponges, suborder Spongillina, are mono-phyletic but that Haplosclerina and Petrosina are polyphy-letic (Itskovich et al, 2007), and Redmond et al (2007) for the same studies in the whole order Haplosclerida. 

Dembitsky, V.M. (2003) Lipid compounds of freshwater sponges family Spongillidae, class Demospongiae. Chem. Phys. Lipids, 123, 117-155. 

Imbs, A.B. and Latyshev, N.A. (1998) New A5 and A4 rmsaturated medimn- and longfatty acids in the freshwater sponge Baicalospon bacilifera. Chem. Phys. Lipids, 92, 117-125. 

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