On the sedimentary occurrence of chlorophyllone a

Abstract The 13 2 ,17 3 -cyclopheophorbide a enol (CPP) is shown to convert mainly to a $1:1 mixture of (13 2 R=S) chlorophyllones a (Chlone), when chromatographed over silica gel or alumina supports. 15 1 -hydroxychlorophyllonelactone a and some other chlorophyll a related compounds are also tentatively identified as minor transformation products of CPP. This raises the possibility that the chlorophyllones reported in recent sediments may be analytical artifacts from CPP. However, data for the surface sediments from Lake Motte as well as literature data for other contemporary sediments show that, (i) they are not artifacts, (ii) considering that CPP is the intermediate compound in the formation of chlorophyllones from chlorophyll a, the hydroxylation of CPP in the sedimentary environment involves an enzymatic process leading preferentially to 13 2 S chlorophyllone a

Géochimie des acides carboxyliques dans les sédiments du lac Cadagno

The free and bound fatty acids were analysed in a 248 cm long sediment core taken from lake Cadagno (Switzerland) to determine the variations of the sedimentary depositional conditions with the depth. Our results show that the factors influencing the sedimentary deposit in the top 0 to 51 cm of the surface sediment are different than those of the deeper sections. An important clastic input, due to the episodic events such as avalanches, land slides and torrential flood, is more frequent between 0 and 51 cm depth. On the other hand, between 51 and 245 cm depth, the sedimentation was more calm, slow and characterized by a high contribution of organic matter produced from higher plants. The microscopic study of these lake sediments also confirms these results. The branched fatty acids iso- and anteiso- > C20, which are never mentionned in geochemical literature, have been found in the sediments bound fractions. Finally, the origin of the sedimentary α- and β-hydroxyacids < C10 has been determined.Les acides gras libres et liés, comprenant les acides monocarboxyliques saturés et insaturés, les acides dicarboxyliques, les (α, β, ω, et ω-1) hydroxyacides et les acides phénoliques, ont été analysés le long d'une carotte sédimentaire de Cadagno (Suisse) dans le but de déterminer les variations des sources et des conditions de déposition de la matière organique en fonction de la profondeur. Les résultats montent que des événements épisodiques tels que les avalanches, glissements de terrains, crues torrentielles, sont plus fréquents entre 0 et 51 cm. Par contre, entre 51 et 245 cm, la sédimentation était plus calme, faible et caractérisée par une contribution plus élevée de la matière organique des plantes supérieures. L'étude microscopique de la matière organique confirme aussi ces résultats. Des acides gras branchés iso- et anteiso- ayant un nombre d'atomes de carbone entre C21 et C29 non mentionnés dans la littérature géochimique jusqu'à présent, ont été détectés dans les fractions liées. Ils proviennent probablement des bactéries spécifiques à ce lac. Finalement, il a été démontré que la source des α- et β-hydroxyacides sédimentaires ayant un nombre d'atomes de carbone < c10 est la même que celles de leurs homologues supérieurs, c.à.d., les bactéries gram-négatives

Identification of New Aromatic Compounds in the New Zealand Manuka Honey by Gas Chromatography-Mass Spectrometry

Analysis of aromatic compounds in the New Zealand manuka honey was carried out by solid phase microextraction followed by gas chromatography-mass spectrometry. A total of 38 compounds were detected. Seven of them such as; 1,4-bis(x-methoxyphenyl)-but-2-en-1-one, 1,5-bis(x-methoxyphenyl)-pent-3-en-1-one, 1,4-bis(x-methoxyphenyl)-1-pentanone, 1,6-bis(x-methoxyphenyl)-3-heptene, 1,6-bis(x-methoxyphenyl)-hex-2(3 or 4)-en-1-one and 2(3, 4 or 5)-hydroxy-1,6-bis(x-methoxyphenyl)-1-hexanone, had never before been identified as natural products. Their structures were deduced from the mass spectral data. Seven other compounds; 2,3-dimethoxynaphthalene, 4-(x-methoxyphenyl)-1-phenyl-1-butanone, desoxyanisoin, 2,6-dimethoxybenzoic acid benzyl ester, 4,4'-dimethoxystilbene, 3,3,4,5,5,8-hexamethyl-2,3,5,6-tetrahydro-s-indacene-1,7-dione and 1,5-bis(4-methoxyphenyl)-pentane-1,5-dione, were found in honey for the first time. Methyl syringate, ortho-methoxyacetophenone and 3-phenyllactic acid were the most abundant components

On the sedimentary occurrence of chlorophyllone a

The 13[2],17[3]-cyclopheophorbide a enol (CPP) is shown to convert mainly to a~1:1 mixture of (13[2]R/S) chlorophyllones a (Chlone), when chromatographed over silica gel or alumina supports. 15[1]-hydroxychlorophyllonelactone a and some other chlorophyll a related compounds are also tentatively identified as minor transformation products of CPP. This raises the possibility that the chlorophyllones reported in recent sediments may be analytical artifacts from CPP. However, data for the surface sediments from Lake Motte as well as literature data for other contemporary sediments show that, (i) they are not artifacts, (ii) considering that CPP is the intermediate compound in the formation of chlorophyllones from chlorophyll a, the hydroxylation of CPP in the sedimentary environment involves an enzymatic process leading preferentially to 13[2]S chlorophyllone a

Molecular Characterization and Subcellular Localization of Macrophage Infectivity Potentiator, a Chlamydia trachomatis Lipoprotein▿

Macrophage infectivity potentiator (MIP) was originally reported to be a chlamydial lipoprotein from experiments showing incorporation of radiolabeled palmitic acid into native and recombinant MIP; inhibition of posttranslational processing of recombinant MIP by globomycin, known to inhibit signal peptidase II; and solubility of native MIP in Triton X-114. However, the detailed structural characterization of the lipid moiety on MIP has never been fully elucidated. In this study, bioinformatics and mass spectrometry analysis, as well as radiolabeling and immunochemical experiments, were conducted to further characterize MIP structure and subcellular localization. In silico analysis showed that the amino acid sequence of MIP is conserved across chlamydial species. A potential signal sequence with a contained lipobox was identified, and a recombinant C20A variant was prepared by replacing the probable lipobox cysteine with an alanine. Both incorporation of U-14C-esterified glycerol and [U-14C]palmitic acid and posttranslational processing that was inhibitable by globomycin were observed for recombinant wild-type MIP but not for the recombinant C20A MIP variant. The fatty acid contents of native and recombinant MIP were analyzed by gas chromatography-mass spectrometry, and the presence of amide-linked fatty acids in recombinant MIP was investigated by alkaline methanolysis. These results demonstrated a lipid modification in MIP similar to that of other prokaryotic lipoproteins. In addition, MIP was detected in an outer membrane preparation of Chlamydia trachomatis elementary bodies and was shown to be present at the surfaces of elementary bodies by surface biotinylation and surface immunoprecipitation experiments