Search

Many benthic marine invertebrates, like barnacles, have a planktonic larval stage whose primary purpose is dispersal. How these species colonize suitable substrata is fundamental to understanding their evolution, population biology, and wider community dynamics. Unlike larval dispersal, settlement occurs on a relatively small spatial scale and involves larval behavior in response to physical and chemical characteristics of the substratum. Biogenic chemical cues have been implicated in this process. Their identification, however, has proven challenging, no more so than for the chemical basis of barnacle gregariousness, which was first described >50 years ago. We now report that a biological cue to gregarious settlement, the settlement-inducing protein complex (SIPC), of the major fouling barnacle Balanus amphitrite is a previously undescribed glycoprotein. The SIPC shares a 30% sequence homology with the thioester-containing family of proteins that includes the [[alpha].sub.2]-macroglobulins. The cDNA (5.2 kb) of the SIPC encodes a protein precursor comprising 1,547 aa with a 17-residue signal peptide region. A number of structural characteristics and the absence of a thioester bond in the SIPC suggest that this molecule is a previously undescribed protein that may have evolved by duplication from an ancestral [[alpha].sub.2]-macroglobulin gene. Although the SIPC is regarded as an adult cue that is recognized by the cyprid at settlement, it is also expressed in the juvenile and in larvae, where it may function in larva-larva settlement interactions. arthropod | larva | pheromone | settlement cue

Axinelloside A was isolated from the lipophilic extract of the Japanese marine sponge Axinella Infundubula as a strong human telomerase inhibitor (IC(sub 50)2.0 mu-g/mL). Axinelloside A consists mainly of twelve sugars such as scyllo-inositol, a D-arabinose, 5 D-galactoses and 5 L-fucoses together with an (R)-3-hydroxy-octadecanoic acid, 3 (E)-2-hexadecenoic acids, and 19 sulfates.

When the mass spectra of biological samples (proteins, peptides, and so on) are obtained routinely by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), a serious problem is the reduction of the ionization efficiency by impurities, such as buffer salts and detergents. We focused our attention on devising a method to maintain the ionization efficiency of protein samples, even in the presence of sodium dodecyl sulfate (SDS), without any extra purification step. Although no protein ion peaks are observed in the presence of 2.5% SDS with the usual methods, the addition of a granular anion exchange silica gel to the matrix solution allowed the protein ion peaks to be obtained with an excellent signal-to-noise ratio. Together with other supporting experiments, we suggest that the positively charged surface (the basic environment derived from the anion exchange groups) and the roughness of the particles were important for good ionization in the presence of a high SDS concentration. For a very uneven surface, the SDS might be absorbed into the particle interiors during the process of cocrystallization with the matrix and analytes, which is known as the molecular sieve effect, and the SDS concentration in the surface crystalline film might be reduced. As a result, we developed an on-probe sample preparation method without washes for MALDI, using a strong anion exchange silica gel. This method is applicable even in the presence of 2.5% SDS, and is not only very simple but also inexpensive, because it can be used with the standard MALDI target plates.

The first 920 MHz high-resolution Nuclear Magnetic Resonance (NMR) magnets are installed at the Tsukuba Magnet Laboratory of the National Institute for Material Science. The signal-to-nose ratio of 0.1 percent ethylbenzene using a proton-selective probe is high as 2981.

A study was conducted to analyze the isolation of four antifouling secosteroids from a Japanese octocoral Dendronephthya sp. The structures were examined using spectroscopic data. Aliquots of the test solutions were placed on a polystyrene 24-well microtiter plate. Experimental results indicated that isogosterones inhibited larval settlement of the barnacle Balanus amphitrite with an EC50 value of 2.2 mu-g/mL.

NMR spectroscopy, structure calculation and energy minimization are applied to determine the three-dimensional structure of polytheonamide B (pTB), a highly cytotoxic polypeptide which is one of the most unusual nonribosomal peptides of sponge origin. The pTB molecules are found to form transmembrane channels that permeate monovalent cations similar to gramicidin A channels and the strong cytotoxicity of pTB could be attributed to its ability to form single molecule channels through biological membranes.

Notoamide E is shown to be a short-lived precursor in the biosynthesis of prenylated indole alkaloids in the mussel-derived Aspergillus sp. The feeding experiment of the [super 13]C-labeled notoamide E has produced structurally novel metabolites.

A study seeks to validate the cation-pi interaction in the polyolefin cascade by incorporating O-methyltyrosine (OMeTyr) and fluorophenylalanines (FluoroPhes) into squalene-hopene cyclase (SHC) in place of the catalytic sites Phe365 and Phe605. These replacements actually increase the SHC activity at low temperature, but decrease it at high temperature, as compared with the wild-type SHC, demonstrating that the pi-electron density of residues 365 and 605 has a crucial role for the efficient polycyclization reaction by SHC.

The first 3D structure of Vanabin2 from an ascidian, Ascidia sydneiensis samea, in an aqueous solution is described. The structure highlighted a novel bow-shaped conformation, with four alpha-helices connected by nine disulfide solutions.