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The ESA mission Rosetta, launched on March 2nd, 2004, carries an instrument suite to the comet 67P/Churyumov-Gerasimenko. The COmetary Secondary Ion Mass Anaylzer -COSIMA -is one of three cometary dust analyzing instruments onboard Rosetta. COSIMA is based on the analytic measurement method of secondary ion mass spectrometry (SIMS). The experiment's goal is in-situ analysis of the elemental composition (and isotopic composition of key elements) of cometary grains. The chemical characterization will include the main organic components, present homologous and functional groups, as well as the mineralogical and petrographical classification of the inorganic phases. All this analysis is closely related to the chemistry and history of the early solar system. COSIMA covers a mass range from 1 to 3500 amu with a mass resolution m/ m @ 50% of 2000 at mass 100 amu. Cometary dust is collected on special, metal covered, targets, which are handled by a target manipulation unit. Once exposed to the cometary dust environment, the collected dust grains are located on the target by a microscopic camera. A pulsed primary indium ion beam (among other entities) releases secondary ions from the dust grains. These ions, either positive or negative, are selected and accelerated by electrical fields and travel a well-defined distance through a drift tube and an ion reflector. A microsphere plate with dedicated amplifier is used to detect the ions. The arrival times of the ions are digitized, and the mass spectra of the secondary ions are calculated from these time-of-flight spectra. Through the instrument commissioning, COSIMA took the very first SIMS spectra of the targets in space. COSIMA will be the first instrument applying the SIMS technique in-situ to cometary grain analysis as Rosetta approaches the comet 67P/Churyumov-Gerasimenko, after a long journey of 10 years, in 2014.

AWN is a boar protein which originates in sccrctions of the male accessory glands and which becomcs sperm surfacc-associated upon cjaculaGon. It is one of the componcms thought to mcdiatc sperm adhesion lo the c&s zona pcllucida through a carbohydrate-recognition mechanism. AWN may. ri~us, participate in the initial cvcnts of fertilization in the pig. In this rcpon WC dcscribc its complete primary structure by combination of protcinchcmical and mass spectromctric methods. AWN exists as two isofonns. AWN-l and AWN-Z which dilRzr in that AWN-Z is N-terminally acctylatcd. The amino acid scqucncc of AWN contains 133 amino acid rcsiducs and two disulphidc bridges bc~wccn nearest-neighbour cyst&e residues. Analysis of the amino acid scquencc of the AWN proteins showed significant similarity only to AQN-I and AQN-3. two other boar spcrmadhcsins.Boar sperm ptotcin: AWN: Spermadhain; Primary structure

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The peptidoglycan layer surrounding the photosynthetic organelles (cyanelles) of the protist Cyanophora paradoxa is thought to be a relic of their cyanobacterial ancestors. The separation of muropeptides by gel filtration and reverse-phase high-performance liquid chromatography revealed four different muropeptide monomers. A number of muropeptides were identical in retention behavior to muropeptides of Escherichia coli, while others had remarkably long retention times with respect to their sizes, as indicated by gel filtration. Molecular mass determination by plasma desorption and matrix-assisted laser desorption ionization mass spectrometry showed that these unusual muropeptides had molecular masses greater by 112 Da or a multiple thereof than those of ones common to both species. Fast atom bombardment-tandem mass spectrometry of these reduced muropeptide monomers allowed the localization of the modification to D-glutamic acid. Highresolution fast atom bombardment-mass spectrometry and amino acid analysis revealed N-acetylputrescine to be the substituent (E. Pittenauer, E. R. Among eukaryotes, peptidoglycan is found only in cyanellecontaining organisms. These consist of about 12 different species and have been grouped under the denomination glaucocystophytes (29). Recently, this has been corroborated by 18S rRNA-derived phylogenetic analysis (5). Cyanophora paradoxa is the only member of this group which can be grown easily; therefore, it is the best investigated one. The round cyanelles of this obligatorily photoautotrophic protist were originally regarded as endosymbiotic cyanobacteria for morphological reasons, such as thylakoid structure (13), carboxysomes (31), and a lysozyme-sensitive peptidoglycan sacculus (37). With the onset of molecular biological investigations of C. paradoxa (18,32), it became clear that the cyanelle genome is smaller than the genomes of unicellular free-living cyanobacteria by a factor of about 25. Thus, cyanelles in fact represent the plastids of C. paradoxa, having retained the peptidoglycan layer which is crucial for division, as indicated by the inhibitory effects of ␤-lactam antibiotics (4, 29). The peptidoglycan layer is located between the organelle membrane and an outer membrane of unknown origin and has a thickness of about 7 nm (30).Investigations of cyanelle peptidoglycan synthesis and degradation have shown that cyanelles apparently harbor a complete set of enzymes involved in these processes. Seven penicillin-binding proteins ranging from 110 to 35 kDa have been identified in the cyanelle envelope by labelling with a radioactive derivative of ampicillin (4). Indirect evidence has been obtained for periplasmic localization of DD-and LD-carboxypeptidases and DD-endopeptidase, enzymes capable of hydrolyzing defined bonds in peptidoglycan (36). The biosynthesis of the UDP-N-acetylmuramyl pentapeptide precursor of peptidoglycan has been shown to occur in the cyanelle stroma (36). The cyanelle genome (135.6 kb) of one of the two known isolates of C. paradoxa, strain LB555-UT...

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Gamete recognition and adhesion are essential steps in fertilization. Among others, carbohydrate-binding proteins on the sperm surface have been recoenized to nlav a central role in the initial interaction of the male aamete with comnonents of the zona pcllucida of the homologous investing oocyte. We have isolated several members of a carbohydrate-and zoia pellucida-binding protein family from ejaculated sperm. Here we report the biological origin and structural characterization of AQN-3, a component of this carbohydrate-binding family. The molecular weight of purified AQN-3 was determined by plasma desorption mass spectrometry. The protein was chemically and enzymatically degraded, the proteolytic fragments isolated and characterized by N-terminal sequencing and fast atom bombardment mass spectrometry. In this manner we established the complete amino acid sequence of AQN-3 and the location of its two disulphide bonds. No analogous protein sequence could be found in the MIPS protein sequence data bank, indicating that AQNJ may belong to a novel mammalian carbohydrate-binding protein family.