ALBERT

Description: An increasing body of evidence suggests that much of the trace metal contamination observed in coastal waters is no longer derived from point-source inputs, but instead originates from diffuse, non-point sources. Previous research has shown that water temperature and dissolved oxygen regulate non-point source processes such as sediment diagenesis; however, limited information is available regarding the effect of these variables on toxic trace metal cycling and speciation in natural waters. Here, we present data on the seasonal variation of dissolved Cu cycling in the Long Island Sound, an urban estuary adjacent to New York City. An operationally defined chemical speciation technique based on kinetic lability and organic complexation has been applied to examine the most ecologically relevant metal fraction. In contrast to the decrease from spring to summer observed in the total dissolved Cu pool (average ± SD:  15.1 ± 4.4 nM in spring and 11.8 ± 3.5 nM in summer), our results revealed that in the highly impacted western LIS, levels of labile Cu reached higher levels in summer (range 3.6−7.7 nM) than in spring (range 1.5− 3.9 nM). Labile Cu in surface waters of the western Sound appeared to have a wastewater source during spring high flow conditions, coinciding with elevated levels of sewage-derived Ag. Labile Cu elsewhere in the LIS during spring apparently resulted from fluvial input and mixing. During summer, labile Cu increased in bottom waters (at one site, bottom water labile Cu increased from 1.5 nM in spring to 7.7 nM in summer), and covariance with tracers of diagenetic remobilization (e.g., Mn) revealed a sedimentary source. Although total dissolved Cu showed no consistent trends with water quality parameters, labile Cu in bottom waters showed an inverse correlation with dissolved oxygen and a positive, exponential correlation with water temperature. These results suggest that future increases in coastal water temperatures may cause the benthic source of labile Cu to become proportionally more significant.

Description: The origin of dissolved organic matter (DOM) within sea ice in coastal waters of the Baltic Sea was investigated using parallel factor (PARAFAC) analysis of DOM fluorescence. Sea ice DOM had distinctly different fluorescence characteristics than that of the underlying humic-rich waters and was dominated by protein-like fluorescence signals. PARAFAC analysis identified five fluorescent components, all of which were present in both sea ice and water. Three humic components were negatively correlated to salinity and concluded to be terrestrially derived material. Baltic Sea ice DOM was found to be a mixture of humic material from the underlying water column incorporated during ice formation and autochthonous material produced by organisms within the ice. Dissolved organic carbon (DOC) and nitrogen (DON) concentrations were correlated to the humic fluorescence, indicating that the majority of the organic carbon and nitrogen in Baltic Sea ice is bound in terrestrial humic material trapped within the ice. This has implications for our understanding of sea ice carbon cycling in regions influenced by riverine input (e.g., Baltic and Arctic coastal waters), as the susceptibility of DOM to degradation and remineralization is largely determined by its source.

Description: Diel cycles of dissolved cationic metal concentrations commonly occur in freshwater streams in apparent response to coincident cycles in water quality parameters (pH, O2, temperature). Hourly sampling of the Cd-contaminated Riou Mort (France) revealed large diel cycles in “total” dissolved Cd (232−357 nM; 〈0.45 μm) and “truly” dissolved Cd (56−297 nM; 〈0.02 μm) which were strongly correlated with changes in water pH. Using measured fluxes, a dissolved O2 model was constructed that indicated that benthic metabolic activities, respiration and photosynthesis, were responsible for the diel O2 (and thus, CO2 and pH) variation in the stream. However, microsensor measurements also showed that the pH changes occurred at the biofilm interface earlier than in the bulk water column. This difference in timing was reflected in the Cd dynamics, where pH-controlled sorption effects caused Cd partitioning from the truly dissolved pool onto the biofilm in the morning, and from the truly dissolved pool onto large colloids (0.02−0.45 μm) later in the day. Because this process causes large changes in the bioavailable Cd fraction, it has significant implications for Cd toxicity in freshwater streams. This study demonstrates the profound control of benthic microbiological processes on the cycling of heavy metals in aquatic systems.

Description: We studied the effect of the quorum-sensing (QS) blockers 5-hydroxy-3[(1R)-1-hydroxypropyl]-4-methylfuran-2(5H)-one (FUR1), (5R)-3,4-dihydroxy-5-[(1S)-1,2-dihydroxyethyl]furan-2(5H)-one (FUR2) and triclosan (TRI) on the formation of bacterial biofilms, and the effect of these biofilms on the larval attachment of the polychaete Hydroides elegans and the bryozoan Bugula neritina. 14-day-old subtidal biofilms were harvested from artificial substrata and were allowed to develop in the laboratory with and without QS blockers. QS blockers inhibited the production of violacein by the QS reporter strain Chromobacterium violaceum CV026 and did not affect the metabolic activity of bacteria in multispecies biofilms. At a concentration of 10(-3) M all three tested compounds inhibited the establishment of microbial communities, but at one of 10(-4) M only FUR2 inhibited establishment. The tested QS blockers caused changes in bacterial density and bacterial community structure, as revealed by terminal restriction fragment length polymorphism and FISH. The groups most affected by QS blockers were Alphaproteobacteria, Gammaproteobacteria and the Cytophagales. Larvae of H. elegans and B. neritina avoided settling on biofilms that had developed in the presence of QS blockers. Our results suggest that QS blockers directly control the formation of multi-species biofilms, and indirectly - by means of biofilm properties - affect larval attachment on these modified biofilms.

Description: The diversity of Cyanobacteria in water and sediment samples from four representative sites of the Salar de Huasco was examined using denaturing gradient gel electrophoresis and analysis of clone libraries of 16S rRNA gene PCR products. Salar de Huasco is a high altitude (3800 m altitude) saline wetland located in the Chilean Altiplano. We analyzed samples from a tributary stream (H0) and three shallow lagoons (H1, H4, H6) that contrasted in their physicochemical conditions and associated biota. Seventy-eight phylotypes were identified in a total of 268 clonal sequences deriving from seven clone libraries of water and sediment samples. Oscillatoriales were frequently found in water samples from sites H0, H1 and H4 and in sediment samples from sites H1 and H4. Pleurocapsales were found only at site H0, while Chroococcales were recovered from sediment samples of sites H0 and H1, and from water samples of site H1. Nostocales were found in sediment samples from sites H1 and H4, and water samples from site H1 and were largely represented by sequences highly similar to Nodularia spumigena. We suggest that cyanobacterial communities from Salar de Huasco are unique - they include sequences related to others previously described from the Antarctic, along with others from diverse, but less extreme environments.

Description: Six new linear peptides, pterulamides I−VI (1−6), were isolated from the fruiting bodies of a Malaysian Pterula species. The structures were elucidated by MS and 2D NMR experiments, and the absolute configurations of the constituent amino acids established using Marfey's method. The pterulamides are mainly assembled from nonpolar N-methylated amino acids and, most interestingly, have non-amino-acid N-terminal groups, among them the unusual cinnamoyl, (E)-3-methylsulfinylpropenoyl, and (E)-3-methylthiopropenoyl groups. Furthermore, pterulamides I−V are the first natural peptides with a methylamide C-terminus. Pterulamides I and IV are cytotoxic against the P388 cell line with IC50 values of 0.55 and 0.95 μg/mL (0.79 and 1.33 μM), respectively.

Description: As ecosystem engineers, seagrasses are angiosperms of paramount ecological importance in shallow shoreline habitats around the globe. Furthermore, the ancestors of independent seagrass lineages have secondarily returned into the sea in separate, independent evolutionary events. Thus, understanding the molecular adaptation of this clade not only makes significant contributions to the field of ecology, but also to principles of parallel evolution as well. With the use of Dr. Zompo, the first interactive seagrass sequence database presented here, new insights into the molecular adaptation of marine environments can be inferred. The database is based on a total of 14 597 ESTs obtained from two seagrass species, Zostera marina and Posidonia oceanica, which have been processed, assembled and comprehensively annotated. Dr. Zompo provides experimentalists with a broad foundation to build experiments and consider challenges associated with the investigation of this class of non-domesticated monocotyledon systems. Our database, based on the Ruby on Rails framework, is rich in features including the retrieval of experimentally determined heat-responsive transcripts, mining for molecular markers (SSRs and SNPs), and weighted key word searches that allow access to annotation gathered on several levels including Pfam domains, GeneOntology and KEGG pathways. Well established plant genome sites such as The Arabidopsis Information Resource (TAIR) and the Rice Genome Annotation Project are interfaced by Dr. Zompo. With this project, we have initialized a valuable resource for plant biologists in general and the seagrass community in particular. The database is expected to grow together with more data to come in the near future, particularly with the recent initiation of the Zostera genome sequencing project. The Dr. Zompo database is available at http://drzompo.uni-muenster.de/

Description: Secretions from the paracloacal glands of alligators (Alligator spp.) and caimans (Caiman spp., Melanosuchus niger, and Paleosuchus spp.) were examined by GC-MS. The secretions of the common caiman (C. crocodilus), the broad-snouted caiman (C. latirostris), the yacare caiman (C. yacare), the dwarf caiman (P. palpebrosus), and the smooth-fronted caiman (P. trigonatus) yielded a new family of 43 aliphatic carbonyl compounds that includes aldehydes, ketones, and β-diketones with an ethyl branch adjacent to the carbonyl group. The identification of these glandular components and the syntheses and stereochemical investigations of selected compounds are described.

Description: Presented here is the complete genome sequence of Thiomicrospira crunogena XCL-2, representative of ubiquitous chemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-sea hydrothermal vents. This gammaproteobacterium has a single chromosome (2,427,734 base pairs), and its genome illustrates many of the adaptations that have enabled it to thrive at vents globally. It has 14 methyl-accepting chemotaxis protein genes, including four that may assist in positioning it in the redoxcline. A relative abundance of coding sequences (CDSs) encoding regulatory proteins likely control the expression of genes encoding carboxysomes, multiple dissolved inorganic nitrogen and phosphate transporters, as well as a phosphonate operon, which provide this species with a variety of options for acquiring these substrates from the environment. Thiom. crunogena XCL-2 is unusual among obligate sulfur-oxidizing bacteria in relying on the Sox system for the oxidation of reduced sulfur compounds. The genome has characteristics consistent with an obligately chemolithoautotrophic lifestyle, including few transporters predicted to have organic allocrits, and Calvin-Benson-Bassham cycle CDSs scattered throughout the genome.

Description: Using HPLC/microtiter-plate-based generation of activity profiles the extract of a marine alga-derived fungus, identified as Gliocladium sp., was shown to contain the known strongly cytotoxic metabolite 4-keto-clonostachydiol (1) and also clonostachydiol (2) as well as gliotide (3), a new cyclodepsipeptide containing several d-amino acids. The absolute configuration of 1 was elucidated by reduction to 2, and two further oxidized derivatives of clonostachydiol (5, 6) were prepared and evaluated for biological activity.

Description: The functional gene amoA was used to compare the diversity of ammonia-oxidizing bacteria (AOB) in the water column and sediment-water interface of the two freshwater lakes Plusssee and Schöhsee and the Baltic Sea. Nested amplifications were used to increase the sensitivity of amoA detection, and to amplify a 789-bp fragment from which clone libraries were prepared. The larger part of the sequences was only distantly related to any of the cultured AOB and is considered to represent new clusters of AOB within the Nitrosomonas/Nitrosospira group. Almost all sequences from the water column of the Baltic Sea and from 1-m depth of Schöhsee were related to different Nitrosospira clusters 0 and 2, respectively. The majority of sequences from Plusssee and Schöhsee were associated with sequences from Chesapeake Bay, from a previous study of Plusssee and from rice roots in Nitrosospira-like cluster A, which lacks sequences from Baltic Sea. Two groups of sequences from Baltic Sea sediment were related to clonal sequences from other brackish/marine habitats in the purely environmental Nitrosospira-like cluster B and the Nitrosomonas-like cluster. This confirms previous results from 16S rRNA gene libraries that indicated the existence of hitherto uncultivated AOB in lake and Baltic Sea samples, and showed a differential distribution of AOB along the water column and sediment of these environments

Description: In a laboratory-based test series, seven experiments along a simulated Pacific hydrotherm at 152°W, 40°N were carried out to measure the rise velocities of liquefied CO2 droplets under (clathrate) hydrate forming conditions. The impact of a hydrate skin on the rising behavior was investigated by comparing the results with those from outside the field of hydrate stability at matching buoyancy. A thermostatted high-pressure tank was used to establish conditions along the natural oceanic hydrotherm. Under P-/T-conditions allowing hydrate formation, the majority of the droplets quickly developed a skin of CO2 hydrate upon contact with seawater. Rise rates of these droplets support the parametrization by Chen et al. (Tellus 2003, 55B, 723−730), which is based on empirical equations developed to match momentum of hydrate covered, deformed droplets. Our data do not support other parametrizations recently suggested in the literature. In the experiments from 5.7 MPa, 4.8 °C to 11.9 MPa, 2.8 °C positive and negative deviations from predicted rise rates occurred, which we propose were caused by lacking hydrate formation and reflect intact droplet surface mobility and droplet shape oscillations, respectively. This interpretation is supported by rise rates measured at P-/T-conditions outside the hydrate stability field at the same liquid CO2-seawater density difference (Δρ) matching the rise rates of the deviating data within the stability field. The results also show that droplets without a hydrate skin ascend up to 50% faster than equally buoyant droplets with a hydrate skin. This feature has a significant impact on the vertical pattern of dissolution of liquid CO2 released into the ocean. The experiments and data presented considerably reduce the uncertainty of the parametrization of CO2 droplet rise velocity, which in the past emerged partly from their scarcity and contradictions in constraints of earlier experiments.

Description: The taxonomy of two sympatric surf clams Donax marincovichi Coan, 1983 and Donax obesulus Reeve, 1854, inhabiting the coastal Humboldt Current Upwelling System is revisited. Because both species are exploited by artisanal fisheries, it is essential to verify that they are indeed distinct species that have to be managed separately. In this study, both taxa were sampled across their shared distributional area and specimens were indentified according to their respective morphological characteristics. Although width/height and height/length ratios revealed significant differences within sampling areas, the two morphotypes were frequently incongruent for taxonomically important morphometric parameters. In addition, they showed no significant mitochondrial genetic differentiation within or among populations and exhibited indistinguishable sperm ultrastructure. We conclude that the two morphotypes do not represent distinct species and should be included together under D. obesulus.

Description: Analysis of stable carbon isotope fractionation is a useful method to study the sources and fate of anthropogenic organic contaminants such as polychlorinated biphenyls (PCBs) in the environment. To evaluate the utility of carbon isotopes, determination of isotopic ratios of 13C/12C in source materials, for example, technical PCB preparations, is needed. In this study, we determined δ13C values of 31 chlorobiphenyl (CB) congeners in 18 technical PCB preparations and 15 chloronaphthalene (CN) congeners in 6 polychlorinated naphthalene preparations using two-dimensional gas chromatography−combustion furnace−isotope ratio mass spectrometry (2DGC−C−IRMS). Development of 2DGC−IRMS enabled improved resolution and sensitivity of compound-specific carbon isotope analysis (CSIA) of CB or CN congeners. δ13C values of PCB congeners ranged from −34.4 (Delors) to −22.0‰ (Sovol). Analogous PCB preparations with similar chlorine content, but different geographical origin, had different δ13C values. PCB preparations from Eastern European countriesDelors, Sovol, Trichlorodiphenyl, and Chlorofenhad distinct δ13C values. PCB mixtures showed increased 13C depletion with increasing chlorine content. δ13C values for individual CB congeners varied depending on the degree of chlorination in technical mixtures. δ13C values of CN congeners in Halowaxes ranged from −26.3 to −21.7‰ and these values are within the ranges observed for PCBs. This study establishes the range of δ13C values in technical PCB and PCN preparations, which may prove to be useful in the determination of sources of these compounds in the environment. This is the first study to employ 2DGC−IRMS analysis of δ13C values in technical PCB and PCN preparations

Description: Bacterial communities associated with the brown alga Laminaria saccharina from the Baltic Sea and from the North Sea were investigated using denaturing gradient gel electrophoresis and 16S rRNA gene clone libraries. The rhizoid, cauloid, meristem and phyloid revealed different 16S rRNA gene denaturing gradient gel electrophoresis banding patterns indicating a specific association of bacterial communities with different parts of the alga. Associations with cauloid and meristem were more specific, while less specific associations were obtained from the old phyloid. In addition, seasonal and geographical differences in the associated communities were observed. Results from 16S rRNA gene libraries supported these findings. Bacterial phylotypes associated with the alga were affiliated with the Alphaproteobacteria (nine phylotypes), Gammaproteobacteria (nine phylotypes) and the Bacteroidetes group (four phylotypes). A number of bacteria associated with other algae and other marine macroorganisms were among the closest relatives of phylotypes associated with L. saccharina.

Description: Microbial isolate Z143-1 found to be associated with an unidentified tunicate was characterized due to its significant antimicrobial activity. Z143-1 is similar to Pseudovibrio ascidiaceicola and Pseudovibrio denitrificans in morphological, physiological and biochemical characteristics, except for its ability to ferment glucose and produce a characteristic red pigment. Fatty acid methyl ester analysis revealed a predominance of the fatty acid 18:1 ω7c at 80.55%, at levels slightly lower than the Pseudovibrio denitrificans type strain DN34T (87.7%). The mol% G+C of Z143-1 is 54.02, relatively higher than the Pseudovibrio denitrificans type strain DN34T and Pseudovibrio ascidiaceicola with mol% G+C of 51.7 and 51.4, respectively. However, phylogenetic analysis of the 16S rRNA gene sequence of Z143-1 showed 100% similarity with the Pseudovibrio denitrificans type strain DN34T. In this study, the bacterium Z143-1 is reported as a new strain of Pseudovibrio denitrificans. While there is no report of a secondary metabolite for Pseudovibrio denitrificans, Z143-1 produces the red pigment heptylprodigiosin, also known as 16-methyl-15-heptyl-prodiginine, which shows anti-Staphylococcus aureus activity.

Description: After the discovery of a potent natural flavonoid glucoside as a potent inhibitor of FabI, a large flavonoid library was screened against three important enzymes (i.e., FabG, FabZ, and FabI) involved in the fatty acid biosynthesis of P. falciparum. Although flavones with a simple hydroxylation pattern (compounds 4−9) showed moderate inhibitory activity toward the enzymes tested (IC50 10−100 μM), the more complex flavonoids (12−16) exhibited strong activity toward all three enzymes (IC50 0.5−8 μM). Isoflavonoids 26−28 showed moderate (IC50 7−30 μM) but selective activity against FabZ. The most active compounds were C-3 gallic acid esters of catechins (32, 33, 37, 38), which are strong inhibitors of all three enzymes (IC50 0.2−1.1 μM). Kinetic analysis using luteolin (12) and (−)-catechin gallate (37) as model compounds revealed that FabG was inhibited in a noncompetitive manner. FabZ was inhibited competitively, whereas both compounds behaved as tight-binding noncompetitive inhibitors of FabI. In addition, these polyphenols showed in vitro activity against chloroquine-sensitive (NF54) and -resistant (K1) P. falciparum strains in the low to submicromolar range.

Description: Siderophores are chelates produced by bacteria as part of a highly specific iron uptake mechanism. They are thought to be important in the bacterial acquisition of iron in seawater and to influence iron biogeochemistry in the ocean. We have identified and quantified two types of siderophores in seawater samples collected from the Atlantic Ocean. These siderophores were identified as hydroxamate siderophores, both ferrioxamine species representative of the more soluble marine siderophores characterized to date. Ferrioxamine G was widely distributed in surface waters throughout the Atlantic Ocean, while ferrioxamine E had a more varied distribution. Total concentrations of the two siderophores were between 3 and 20 pM in the euphotic zone. If these compounds are fully complexed in seawater, they represent approximately 0.2-4.6 of the 〈0.2 μm iron pool. Our data confirm that siderophore-mediated iron acquisition is important for marine heterotrophic bacteria and indicate that siderophores play an important role in the oceanic biogeochemical cycling of iron. © 2008 American Chemical Society.

Description: Four surveys of the Huelva Estuary in southwest Spain and its sources, the Tinto and the Odiel Rivers, were carried out between 1996 and 1998. The surveys investigated the impact of metalliferous mining of sulfide-rich ores in the catchment area on metal speciation, metal concentrations in a macrophyte, and phytoplankton diversity and abundance. Chemical speciation measurements in the lower Tinto Estuary showed that metals were predominantly electrochemically labile (>99 of total dissolved Cu, Co, and Ni at 10 μM Cu, 424 nM Co, and 500 nM Ni, S = 28). Concentrations of Cu complexing ligands and free cupric ions Cu2+ in the Gulf of Cádiz ranged between 5.3 and 38 nM and 0.2-7.9 pM, respectively, with conditional stability constants of the ligands of log K′CuL = 11.7-12.6. At enhanced dissolved Cu concentrations in the lower Huelva Estuary, Cu complexing ligands were saturated with Cu, resulting in nanomolar Cu2+, which increased upstream. Metal tissue concentrations of the macrophyte Blindingia marginata were high, and a clear relationship between dissolved labile Cu and macrophyte tissue Cu concentrations was observed. A low biodiversity was observed in the Huelva system (Shannon-Wiener indices (H) typically 〈0.2). Nevertheless, the maximum biomass was observed in the lower Tinto Estuary, which showed high labile metal and nutrient concentrations and a low biodiversity (H 〈 0.02), thereby suggesting adaptation through evolutionary processes of the phytoplankton community to the harsh conditions. © 2007 American Chemical Society.

Description: The scientific discipline of active restoration of denuded coral reef areas has drawn much attention in the past decade as it became vident that this ecosystem does not ofte recover naturally from anthropogenic stress without manipulation. Essentially, the choices are either the continuous degradation of the reefs or active restoration to encourage reef development. As a result, worldwide restoration operations during the past decade have been recognized as being a major tool for reef rehabilitation. This situation has also stirred discussions and debates on the various restoration measures suggested as management options, supplementary to the traditional conservation acts. The present essay reviews past decade’s (1994-2004) approaches and advances in coral reef restoration. While direct coral transplantation is still the primer vehicle of operations used, the concept of in situ and ex situ coral nurseries (the gardening concept), where coral materials (nubbins, branches, spats) are maricultured to a size suitable for transplantation, has been gaining recognition. The use of nubbins (down to the size of a single or few polyps) has been suggested and employed as a unique technique for mass production of coral colonies. Restoration of ship grounding sites and the use of artificial reefs have become common tools for specific restoration needs. Substrate stabilization, 3-D structural consideration of developing colonies, and the use of molecular/biochemical tools are part of novel technology approaches developed in the past decade. Economic considerations for reef restoration have become an important avenue for evaluating success of restoration activities. It has been suggested that landscape restoration and restoration genetics are important issues to be studied. In the future, as coral reef restoration may become the dominant conservation act, there would be the need not only to develop improved protocols but also to define the conceptual bases.

Description: The basal position of the Mamiellales (Prasinophyceae) within the green lineage makes these unicellular organisms key to elucidating early stages in the evolution of chlorophyll a/b-binding light-harvesting complexes (LHCs). Here, we unveil the complete and unexpected diversity of Lhc proteins in Ostreococcus tauri, a member of the Mamiellales order, based on results from complete genome sequencing. Like Mantoniella squamata, O. tauri possesses a number of genes encoding an unusual prasinophyte-specific Lhc protein type herein designated "Lhcp". Biochemical characterization of the complexes revealed that these polypeptides, which bind chlorophylls a, b, and a chlorophyll c-like pigment (Mg-2,4-divinyl-phaeoporphyrin a 5 monomethyl ester) as well as a number of unusual carotenoids, are likely predominant. They are retrieved to some extent in both reaction center I (RCI)- and RCII-enriched fractions, suggesting a possible association to both photosystems. However, in sharp contrast to previous reports on LHCs of M. squamata, O. tauri also possesses other LHC subpopulations, including LHCI proteins (encoded by five distinct Lhca genes) and the minor LHCII polypeptides, CP26 and CP29. Using an antibody against plant Lhca2, we unambiguously show that LHCI proteins are present not only in O. tauri, in which they are likely associated to RCI, but also in other Mamiellales, including M. squamata. With the exception of Lhcp genes, all the identified Lhc genes are present in single copy only. Overall, the discovery of LHCI proteins in these prasinophytes, combined with the lack of the major LHCII polypeptides found in higher plants or other green algae, supports the hypothesis that the latter proteins appeared subsequent to LHCI proteins. The major LHC of prasinophytes might have arisen prior to the LHCII of other chlorophyll a/b-containing organisms, possibly by divergence of a LHCI gene precursor. However, the discovery in O. tauri of CP26-like proteins, phylogenetically placed at the base of the major LHCII protein clades, yields new insight to the origin of these antenna proteins, which have evolved separately in higher plants and green algae. Its diverse but numerically limited suite of Lhc genes renders O. tauri an exceptional model system for future research on the evolution and function of LHC components. © The Author 2005. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved.

Description: Sansalvamide A, a cyclic depsipeptide isolated from a marine fungus of the genus Fusarium, is composed of four hydrophobic amino acids (Phe, two Leu, Val) and one hydroxy acid ((S)-2-hydroxy-4-methylpentanoic acid; O-Leu) with five stereogenic centers all having S-stereochemistry. We have recently synthesized the corresponding cyclic peptide (Gu, W.; Liu, S.; Silverman, R. B. Organic Lett. 2002, 4, 4171−4174) and found that it too has antitumor activity. N-Methylation can enhance potency and selectivity for peptides. Consequently, here we synthesize 12 different N-methylated sansalvamide A peptide analogues and show that for several different tumor cell lines three of these analogues are more potent than the natural product; in pancreatic cells, sansalvamide A shows little activity, but the N-methylsansalvamide peptides are potent cytotoxic agents.

Description: Background During the Ordovician the global diversity increased dramatically at family, genus and species levels. Partially the diversification is explained by an increased nutrient, and phytoplankton availability in the open water. Cephalopods are among the top predators of todays open oceans. Their Ordovician occurrences, diversity evolution and abundance pattern potentially provides information on the evolution of the pelagic food chain. Methodology/Principal Findings We reconstructed the cephalopod departure from originally exclusively neritic habitats into the pelagic zone by the compilation of occurrence data in offshore paleoenvironments from the Paleobiology Database, and from own data, by evidence of the functional morphology, and the taphonomy of selected cephalopod faunas. The occurrence data show, that cephalopod associations in offshore depositional settings and black shales are characterized by a specific composition, often dominated by orthocerids and lituitids. The siphuncle and conch form of these cephalopods indicate a dominant lifestyle as pelagic, vertical migrants. The frequency distribution of conch sizes and the pattern of epibionts indicate an autochthonous origin of the majority of orthocerid and lituitid shells. The consistent concentration of these cephalopods in deep subtidal sediments, starting from the middle Tremadocian indicates the occupation of the pelagic zone early in the Early Ordovician and a subsequent diversification which peaked during the Darriwilian. Conclusions/Significance The exploitation of the pelagic realm started synchronously in several independent invertebrate clades during the latest Cambrian to Middle Ordovician. The initial rise and diversification of pelagic cephalopods during the Early and Middle Ordovician indicates the establishment of a pelagic food chain sustainable enough for the development of a diverse fauna of large predators. The earliest pelagic cephalopods were slowly swimming vertical migrants. The appearance and early diversification of pelagic cephalopods is interpreted as a consequence of the increased food availability in the open water since the latest Cambrian.

Description: Mechanisms that affect thermal tolerance of ectothermic organisms have recently received much interest, mainly due to global warming and climate-change debates in both the public and in the scientific community. In physiological terms, thermal tolerance of several marine ectothermic taxa can be linked to oxygen availability, with capacity limitations in ventilatory and circulatory systems contributing to oxygen limitation at extreme temperatures. The present review briefly summarizes the processes that define thermal tolerance in a model cephalopod organism, the cuttlefish Sepia officinalis, with a focus on the contribution of the cephalopod oxygen-carrying blood pigment, hemocyanin. When acutely exposed to either extremely high or low temperatures, cuttlefish display a gradual transition to an anaerobic mode of energy production in key muscle tissues once critical temperatures (Tcrit) are reached. At high temperatures, stagnating metabolic rates and a developing hypoxemia can be correlated with a progressive failure of the circulatory system, well before Tcrit is reached. However, at low temperatures, declining metabolic rates cannot be related to ventilatory or circulatory failure. Rather, we propose a role for hemocyanin functional characteristics as a major limiting factor preventing proper tissue oxygenation. Using information on the oxygen binding characteristics of cephalopod hemocyanins, we argue that high oxygen affinities (= low P50 values), as found at low temperatures, allow efficient oxygen shuttling only at very low venous oxygen partial pressures. Low venous PO2s limit rates of oxygen diffusion into cells, thus eventually causing the observed transition to anaerobic metabolism. On the basis of existing blood physiological, molecular, and crystallographical data, the potential to resolve the role of hemocyanin isoforms in thermal adaptation by an integrated molecular physiological approach is discussed.

Description: The U.S. Department of Energy's National Energy Technology Laboratory (NETL) located in Albany, OR (formerly the Albany Research Center) has studied ex situ mineral carbonation as a potential option for carbon dioxide sequestration. Studies focused on the reaction of Ca−, Fe−, and Mg−silicate minerals with gaseous CO2 to form geologically stable, naturally occurring solid carbonate minerals. The research included resource evaluation, kinetic studies, process development, and economic evaluation. An initial cost estimate of ∼$69/ton of CO2 sequestered was improved with process improvements to ∼$54/ton. The scale of ex situ mineral carbonation operations, requiring ∼55 000 tons of mineral to carbonate, the daily CO2 emissions from a 1-GW, coal-fired power plant, may make such operations impractical.

Description: Recent molecular studies investigating higher-level phylogenetics of coleoid cephalopods (octopuses, squids and cuttlefishes) have produced conflicting results. A wide range of sequence alignment and analysis methods are used in cephalopod phylogenetic studies. The present study investigated the effect of commonly used alignment and analysis methods on higher-level cephalopod phylogenetics. Two sequence homology methods: (1) eye alignment, (2) implied alignment, and three analysis methods: (1) parsimony, (2) maximum likelihood, (3) Bayesian methodologies, were employed on the longest sequence dataset available for the coleoid cephalopods, comprising three mitochondrial and six nuclear loci. The data were also tested for base composition heterogeneity, which was detected in three genes and resolved using RY coding. The Octopoda, Argonautoidea, Oegopsida and Ommastrephidae are monophyletic in the phylogenies resulting from each of the alignment and analysis combinations. Furthermore, the Bathyteuthidae are the sister taxon of the Oegopsida in each case. However many relationships within the Coleoidea differed depending upon the alignment and analysis method used. This study demonstrates how differences in alignment and analysis methods commonly used in cephalopod phylogenetics can lead to different, but often highly supported, relationships.

Description: A new cyclic pentapeptide, chrysosporide (1), was isolated from a New Zealand sample of the mycoparasitic fungus Sepedonium chrysospermum by bioactivity-guided fractionation. The planar structure was deduced by detailed spectroscopic analysis, and the absolute configurations of the amino acid residues were defined by Marfey's method. As both enantiomers of Leu occurred in chrysosporide, molecular mechanics calculations were applied to the analysis to distinguish between the possible structural isomers. Only the lowest energy conformers of the cyclo-(l-Val-d-Ala-l-Leu-l-Leu-d-Leu) isomer were in agreement with the observed NOEs, suggesting that this was the most probable amino acid sequence for chrysosporide (1).

Description: An unusual oxalylated tetramic acid, pachydermin (1), has been isolated from the New Zealand basidiomycete Chamonixia pachydermis. The full structure, which was not directly accessible by NMR methods, was deduced from that of a degradation product, 5-(3-chloro-4-hydroxybenzylidene)tetramic acid (2). The degradation product 2 exhibited mild antibacterial activity against Bacillus subtilis.

Description: Over recent years, several PCR primers have been described to amplify genes encoding the structural subunits of ammonia monooxygenase (AMO) from ammonia-oxidizing bacteria (AOB). Most of them target amoA, while amoB and amoC have been neglected so far. This study compared the nucleotide sequence of 33 primers that have been used to amplify different regions of the amoCAB operon with alignments of all available sequences in public databases. The advantages and disadvantages of these primers are discussed based on the original description and the spectrum of matching sequences obtained. Additionally, new primers to amplify the almost complete amoCAB operon of AOB belonging to Betaproteobacteria (betaproteobacterial AOB), a primer pair for DGGE analysis of amoA and specific primers for gammaproteobacterial AOB, are also described. The specificity of these new primers was also evaluated using the databases of the sequences created during this study.