Identification of the cellular site of polychlorinated peptide biosynthesis in the marine sponge Dysidea (Lamellodysidea) herbacea and symbiotic cyanobacterium Oscillatoria spongeliae by CARD-FISH analysis

Populations of the sponge Dysidea (Lamellodysidea) herbacea, which host the cyanobacterium Oscillatoria spongeliae, vary in their production of polychlorinated peptides. Peptide natural products previously isolated from D. herbacea are often halogenated and include dysidin, dysidinin, and a series of chlorinated diketopiperazines. Strikingly, the distinctive leucine-derived trichloromethyl signature of these compounds is shared only with metabolites of the marine cyanobacterium Lyngbya majuscula, and includes such compounds as barbamide and nordysidinin. Genetic information available for the barbamide biosynthetic gene cluster was used to successfully polymerase chain reaction (PCR) amplify a barB1 homolog (dysB1) from D. herbacea samples collected in Papua New Guinea. Catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) analysis showed that dysB1 oligonucleotide probes hybridized to sequences in the filamentous cyanobacterial symbiont O. spongeliae. Consistent with this finding, a D. herbacea/O. spongeliae collection devoid of the polychlorinated peptides did not contain the barB1 homologs.Communicated by P.W. Sammarco, Chauvin     

Isolation of Oscillatoria spongeliae,the filamentous cyanobacterial symbiont of the marine sponge Dysidea herbacea

The tropical marine sponge Dysidea herbacea (Keller) (Dictyoceratidae: Dysideidae) is always found associated with the filamentous cyanobacterium (blue-green alga) Oscillatoria spongeliae (Schulze) Hauck (Cyanophyceae: Oscillatoriaceae), which occurs abundantly throughout the sponge mesohyl. Intact, metabolically active, trichomes of O. spongeliae were isolated from the sponge by chopping the sponge tissue with a razor blade and squeezing the trichomes into a seawater-based medium containing polyvinylpyrrolidone, bovine serum albumin, dithiothreitol, glycerol, KCl and Na₂CO₃. The isolated cyanobacteria were concentrated by centrifugation and then washed several times in fresh medium. The isolated O. spongeliae have photosynthetic rates which are similar to the intact sponge-alga association for periods of at least 6 h after isolation. Addition of sponge homogenate to the isolated cyanobacteria causes rapid cell lysis.     

Occurrence and profiles of polybrominated diphenyl ethers (PBDEs) in riverine sediments of Shanghai: a combinative study with human serum from the locals

Herein, we studied the occurrence and profiles of thirteen PBDE congeners in 30 river sediment samples from Shanghai, China. The concentrations of Σ₁₃PBDEs ranged from 110 to 13,071 pg g ^?1 dw, with an average value of 2,841 pg g ^?1 dw. BDE-209 was the predominant congener accounting for more than 65 % of total PBDEs, demonstrating that the major source of PBDEs in sediment samples was associated with the prevalent use of technical deca-BDE products. Moreover, low brominated BDEs in sediments also came from the degradation of higher brominated BDEs. In addition, taking into consideration of dietary exposure, PBDEs in serum samples collected from the locals were also detected with range of 419–26,744 pg g^?1 (average 5,561 pg g ^?1), which suggested a relatively low burden of PBDEs contamination to human body compared with the condition in other place. And in serum, low brominated compounds constituted the majority of total PBDE congeners.     

Population structure of the black tiger prawn, Penaeus monodon, among western Indian Ocean and western Pacific populations

We examined the population structure of the black tiger prawn, Penaeus monodon Fabricius, 1798, in the Indo-West Pacific by analyzing the geographic distribution of elongation factor 1-alpha intron sequences from specimens collected during the winter and spring of 1997. Both the molecular phylogeny of alleles and F-statistics indicated very strong differentiation between populations from the western Indian Ocean and western Pacific. This pattern is concordant with other recent studies of marine species in this region, implying that the Indo-Australian Archipelago represents a biogeographic break between populations in the Indo-West Pacific. F _ST-values among populations in the western Indian Ocean also indicate structure within this region, whereas no structure was found among western Pacific populations. Nucleotide diversity was significantly lower in the western Indian Ocean populations than in the western Pacific, implying that the populations have regional differences in demographic history. Received: 16 November 1998 / Accepted: 26 May 1999     

Deconstructing an assemblage of “turtle” barnacles: species assignments and fickle fidelity in Chelonibia

Barnacles in the genus Chelonibia are commensal with a variety of motile marine animals including sea turtles, crustaceans, and sirenians. We conducted a worldwide molecular phylogenetic survey of Chelonibia collected from nearly all known hosts to assess species relationships, host-fidelity, and phylogeographic structure. Using DNA sequences from a protein-coding mitochondrial gene (COI), a mitochondrial rRNA gene (12S), and one nuclear rRNA gene (28S), we found that of four species, three (C. testudinaria, C. patula, and C. manati) are genetically indistinguishable. In addition, we show each utilizes a rare androdioecious mode of reproduction involving complemental males. In contrast, the fourth species (C. caretta), which is hermaphroditic and specializes on turtles, is genetically distinct—leading to the conclusion that the three former taxa are morphotypes of the same species and should be synonymized under C. testudinaria. Phylogenetic analysis resulted in three geographic clades (Atlantic, Indian Ocean/western Pacific, and eastern Pacific) with haplotype parsimony networks revealing no shared haplotypes among geographic regions. Analysis of molecular variance detected significant differences among sequences by region (p < 0.005); conversely, there were no significant differences among sequences when grouped by host or taxonomic designation. Average pairwise genetic distances were lower between the eastern Pacific and Atlantic clades (0.053 ± 0.006) than between the eastern Pacific and Indian Ocean/western Pacific clades (0.073 ± 0.008), suggesting Atlantic and eastern Pacific populations were connected more recently, perhaps until the rise of the Isthmus of Panama. Host use by Chelonibia morphotypes is discussed along with speculation on possible ancestral hosts and support for a “turtle-first” hypothesis.     

A brominated secondary metabolite synthesized by the cyanobacterial symbiont of a marine sponge and accumulation of the crystalline metabolite in the sponge tissue

The dictyoceratid marine sponge Dysidea herbacea (Keller, 1889) is common in shallow waters of the tropical Pacific Ocean. Polybrominated biphenyl ethers such as 2-(2,4-dibromophenyl)-4,6-dibromophenol (1) are characteristic secondary metabolites of some specimens of this sponge and may represent as much as 12% of the dry weight. We have found 1 to be deposited as conspicuous crystals throughout the sponge tissue. The dominant prokaryotic endosymbiont in the mesohyl of the sponge is a filamentous cyanobacterium (Oscillatoria spongeliae), although a vacuole-containing, heterotrophic bacterium is also present. The cyanobacteria were separated from the sponge cells and heterotrophic bacteria by flow cytometry. Coupled gas chromatography—mass spectrometry and proton nuclear magnetic-resonance spectroscopy revealed that the major brominated Compound 1 isolated from the intact symbiotic association is found in the cyanobacteria and not in the sponge cells or heterotrophic bacteria. This suggests that the production of the compound is due to the cyanobacterium, and not to the sponge or symbiotic heterotrophic bacteria, as had been suggested earlier.     

Biochemical composition and energy reserves in the larvae and adults of the four british periwinkles Littorina littorea,L. littoralis,L. saxatilis and L. neritoides

The biochemical composition of the adult body tissue is similar in Littorina littorea, L. littoralis, L. saxatilis and L. neritoides. In the newly crawling metamorphosed young of L. littoralis and L. saxatilis, the biochemical composition is similar to that of the mature adults. The newly released planktonic veliger larvae of L. littorea and L. neritoides, which represent and earlier stage of development than the newly crawling young, have a neutral lipid level (mean, 16.5% of ash-free dry flesh weight) approximately three times the level (5.4%) in the newly crawling young of L. littoralis and L. saxatilis. Otherwise the biochemical composition of free-swimming larvae is similar to that of newly crawling young and adults. Neutral lipid is apparently utilised by L. littoralis and L. saxatilis larvae during larval development and metamorphosis. It is suggested that neutral lipid is the major energy reserve of Littorina veliger larvae whereas in the adults, as exemplified by L. littorea, both lipid and carbohydrate are important as energy reserves.     

Comparaison biochimique de quatre espèces de copépodes planctoniques de Méditerranée nord-occidentale à partir des enzymogrammes des estérases,de la leucine aminopeptidase,de la phosphatase alcaline,de la malate déshydrogénase et de l'enzyme malique

Four copepod species (Acartia clausi, Centropages typicus, Temora stylifera, Calanus helgolandicus) from the northwest Mediterranean were subjected to electrophoresis on polyacrylamide gel in an attempt to distinguish specific biochemical characteristics for each species. Enzymograms of 5 enzymes were studied: esterases, leucine aminopeptidase, alkaline phosphatase, malate dehydrogenase and the malic enzyme. Marked interspecific differences were revealed, enabling specific biochemical identities to be established which can be useful as taxonomic criteria in the same way as morphological characteristics. The study was performed during different seasons in 1980.     

Partitioning of polybrominated diphenyl ether (PBDE) congeners in human blood and milk

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants (BFRs) which have recently been detected in human blood and milk in the USA, and presently these PBDE levels are found to be the highest globally. On a population basis, individual blood and individual milk analyses show similar congener patterns and levels. Until now, there has not been a study comparing PBDE levels in milk and blood of the same individuals. This study is the first to report these levels for PBDEs, though partitioning between blood and milk has been done previously for dioxins and polychlorinated biphenyls (PCBs). Twelve congeners in 11 nursing mothers’ blood and milk were found and the data describe partitioning ratios between blood and milk. The data suggest it may be easier for smaller, less brominated congeners to move from blood to milk.     

Phylogeny and biogeographic history of hake (genus Merluccius), inferred from mitochondrial DNA control-region sequences

 Phylogenetic analyses of the left domain of the mitochondrial DNA control-region sequence have been used to examine the relationships among species of the genus Merluccius (Rafinesque, 1810), and to compare these with hypotheses based on morphological, meristic and allozyme characters. Analysis of aligned sequences revealed that transition bias was much lower than in mammalian mtDNA, and that nucleotide composition of control-region sequences was biased toward A and T. We have roughly calibrated a molecular clock for the genus, based on the rise of the Isthmus of Panamá, which is believed to have created a barrier to dispersal between marine species of the Atlantic and Pacific Oceans. Our mtDNA-based phylogeny was highly congruent with allozyme-based phylogenies, but poorly so with a previously described phylogeny based on morphology. Specifically, our phylogeny resolved two well-supported principal clades, one of American (west Atlantic and east Pacific) species and the other of Euro–African (east Atlantic) species. This suggests an evolutionary history during which the ancestral lineage of Merluccius was divided between two geographic regions, with subsequent dispersal and vicariant events resulting in the evolution and distribution of extant taxa. However, the relationships between some taxa within the American clade could not be resolved. We suggest that this is consistent with an hypothesis of a rapid origin and radiation of these taxa. Received: 12 December 1998 / Accepted: 15 October 1999     

The introduction of Littorina littorea to British Columbia, Canada: potential impacts and the importance of biotic resistance by native predators

Although the establishment and spread of non-indigenous species depends upon survival in the face of novel environmental conditions and novel biological interactions, relatively little attention has been focused on the specific role of native predators in limiting invasion success. The European common periwinkle, Littorina littorea, was recently introduced to the Pacific coast of Canada and provides a case study of an introduction into an area with an important predator guild (sea stars) that is functionally minor in the invader’s native habitat. Here, we assess the likelihood of establishment, spread, and negative ecological impact of this introduced gastropod, with an emphasis on the role of native sea stars as agents of biotic resistance. Size frequency distributions and local market availability suggest that L. littorea was most likely introduced via the live seafood trade. Non-native hitchhikers (e.g., the trematode Cryptocotyle lingua) were found on/in both market and field specimens. Laboratory studies and field observations confirmed that L. littorea can survive seasonal low salinity in Vancouver, British Columbia. Periwinkles also readily consumed native Ulva, suggesting that periwinkles could impact native communities via herbivory or resource competition. Unlike native gastropods, however, L. littorea lacked behavioural avoidance responses to Northeast Pacific predatory sea stars (Pisaster ochraceus and Pycnopodia helianthoides), and sea star predation rates on L. littorea were much higher than predation rates on native turban snails (Chlorostoma funebralis) in common garden experiments. We therefore expect periwinkle establishment in British Columbia to be limited to areas with low predator density, as is seen in its field distribution to date. We caution that this conclusion may understate the importance of the L. littorea introduction if it also serves as a vector for additional non-indigenous species such as C. lingua.     

Brominated flame retardants and dechlorane plus on a remote high mountain of the eastern Tibetan Plateau: implications for regional sources and environmental behaviors

We investigated the occurrence of halogenated flame retardants (HFRs) including polybrominated diphenyl ethers (PBDEs), six novel brominated flame retardants (NBFRs) and dechlorane plus in air and soils on the eastern slope of Mt. Gongga on the eastern Tibetan Plateau. We detected all of the NBFR except bis(2-ethylhexyl)-tetrabromophthalate and pentabromoethyl benzene. NBFRs constituted the most prevalent group. BDE-28 and BDE-47 dominated among the PBDE congeners. Decabromodiphenyl ethane was detected at relatively high levels up to 171 pg/m³ and 1450 pg/g dry weight in air and soils, respectively; however, it appeared to be easily degraded in the environment. A general decreasing trend was observed among the HFR concentrations with increasing altitude, and this was due to the prominent contribution of source emissions over possible influence of environmental conditions. This study also suggests that HFRs are supplied to forest soils mainly in the form of precipitation and retained in the O horizon layers.     

DDT und Metaboliten in Sedimenten Berliner Gewässer

Sediment samples from rivers and lakes of Berlin (Germany) were analysed for their contamination with organic compounds by means of qualitative and quantitative GC/MS analysis. The principal compounds detected were PAH, organotin derivates, several classes of chlorinated, brominated and mixed halogenated compounds and some of their related metabolites. The DDT metabolites DDD, DDE, DDCN, DDMU and DDMS were the most abundant compounds of halogenated pesticides in a wide range of samples. The main metabolite determined was p,p′-DDD, with concentrations up to 1230 μg/kg dw. The parent DDT compound was detected in only a few samples. The acute cytotoxicity of selected DDT-metabolites was determined with the permanent cell line RTG-2 from the gonads of the rainbow trout (Oncorhynchus mykiss). The results indicate a high cytotoxic potential of these metabolites. The oestrogenic potential was determined by the Dot-Blot/RNase-Protection-Assay an the order from o,p′-DDT>p,p′-DDMS>p,p′-DDMU≥p,p′-DDCN. Risk assessments based on chemical analysis of DDT, DDD and DDE alone is not able to estimate the real toxic potential of DDT and its metabolites. The development of a method for bioassay directed assessment seems to be an effective strategy to solve this problem. Especially scarce or not available data of combinatory effects, differences between different trophic levels and their availability to biota and low knowledge about the metabolism in situ as well as the enantioselective characteristics of most chiral DDT metabolites warrant future analyses.     

Low variation in partial cytochrome oxidase subunit I (COI) mitochondrial sequences in the coralline demosponge Astrosclera willeyana across the Indo-Pacific

Partial sequences of the mitochondrial DNA (mtDNA) gene cytochrome oxidase subunit 1 (COI) were analysed from individuals of the coralline demosponge Astrosclera willeyana sensu lato out of ten Indo-Pacific populations from the Red Sea to the central Pacific. This taxon is widely distributed in cryptic coral reef habitats of the Indo-Pacific and is regarded as a modern representative of long-extinct, formerly reef-building stromatoporoid-type sponges. The aims were to clarify phylogeographic and taxonomic relationships in this “living fossil” and to explore mitochondrial DNA sequence variation over a wide geographic range. Very low variability was observed across the Indo-Pacific, as only three COI haplotypes were identified, with a maximum p-distance of 0.418% and low nucleotide diversity (π=0.00049). Very low genetic structure was revealed among populations: Haplotype 1 was found in all specimens from nine Pacific populations (N=45), separated by distances of more than 7,000 km; haplotype 2 was restricted to the Red Sea population (N=4); haplotype 3 was only found in the Tuamoto specimens (N=7). COI data presented here do not support the hypothesis of at least two sibling species belonging to genus Astrosclera in the Pacific. Considering the maximum geographic distance of more than 20,000 km between sampled populations, mtDNA COI sequence variation observed here is among the lowest reported to date for a diploblastic taxon and adds to the growing evidence of a general mtDNA conservation in sponges. It is argued that this low mtDNA variation in A. willeyana s.l. is due to a low rate of mtDNA evolution caused by a combination of long generation time and low metabolic rate.     

Calanus marshallae,a new species of calanoid copepod closely allied to the sibling species C. finmarchicus and C. glacialis

Species of the copepod genus Calanus frequently dominate the marine zooplankton in boreal and arctic waters. Up to now there have been no operational means of identifying several species closely related to Calanus finmarchicus. Reanalysis of these taxa, using material from plankton samples collected throughout Northern Hemisphere polar and coreal waters, shows that there are 3 sibling species which have been previously combined under the names C. finmarchicus and C. glacialis. Several new taxonomic characters permit unequivocal identification of C. finmarchicus, C. glacialis, and a new species, C. marshallae. Claims that C. finmarchicus and C. glacialis are subspecies are refuted; there is no evidence that the two species continuously intergrade either where they co-occur or where they are allopatric, nor is there evidence that the two species hybridize. C. finmarchicus is basically restricted to the North Atlantic Ocean and C. marshallae to the North Pacific Ocean and Bering Sea; C. glacialis is primarily an Arctic species, but its geographical distribution slightly overlaps those of the other two species. Taxa closely related to C. finmarchicus and C. helgolandicus probably represent two separate, but closely linked evolutionary lineage; species of these two lineages are placed in one of two species groups, the finmarchicus group and the helgolandicus group.     

Population structure of the widely dispersing marine bryozoan Membranipora membranacea (Cheilostomata): implications for population history, biogeography, and taxonomy

Morphologically plastic, cryptic, or geographically widespread species pose similar challenges to the evolutionary biologist: their taxonomic status is often unclear yet must be known to study almost any aspect of their biology, ecology, evolution, or biogeography. The marine bryozoan Membranipora membranacea (L.) is morphologically plastic and geographically widespread in temperate oceans of the Northern and Southern Hemispheres, and its taxonomy is unclear. This study examined genetic relationships among allopatric populations and sympatric morphs of this species, or species complex. Colonies were collected from 1992 to 1995. Allozymes were used to elucidate the relationships among four widely separated populations, two in the North Atlantic and two in the North Pacific Ocean. Allozymes and mtDNA sequencing were used to clarify the genetic relationships among three sympatric morphs that might correspond to the species M. villosa Hincks and M. membranacea in the northeastern Pacific (Washington State). Populations in the North Atlantic and North Pacific had no fixed allelic differences at the loci tested but were separated by an average Nei's genetic distance of 0.581, suggesting their near-sibling species status. Populations from Friday Harbor (Washington) and Catalina Island (California) were not significantly differentiated, which was attributed to high gene flow. Populations on either side of the North Atlantic were genetically indistinguishable, which is most likely due to the recent establishment of the West Atlantic populations from European founders. At Friday Harbor, sympatric morphs varying in their spination and spine inducibility were genetically indistinguishable, supporting the hypothesis that M. villosa is an induced phenotype of M. membranacea and not a distinct species in the northeastern Pacific. Since such phenotypic plasticity is common in cheilostome bryozoans, the morphospecies concept must be used with caution. Received: 31 August 1998 / Accepted: 10 August 1999     

水生和陆生生物体中卤系阻燃剂的差异性富集研究:以鲶鱼和家鸽为例

分析了水生(鲶鱼)和陆生(家鸽)生物体中卤系阻燃剂(HFRs)的组成和浓度。鲶鱼中短链氯化石蜡(SCCPs)浓度均值为30 800 ng·g~(-1)lw(脂肪归一化浓度),是最主要的HFRs,然后依次是多溴联苯醚(PBDEs)(2 300 ng·g~(-1)lw)、四溴双酚A(TBBPA)(37 ng·g~(-1)lw)、六溴环十二烷(HBCD)(21 ng·g~(-1)lw)、德克隆(DP)(14 ng·g~(-1)lw)、十溴二苯乙烷(DBDPE)(7.1 ng·g~(-1)lw)和六溴苯(HBB)(6.2 ng·g~(-1)lw);而家鸽中PBDEs含量最高(17 000 ng·g~(-1)lw),其次是SCCPs(7 600 ng·g~(-1)lw)DP(1 600 ng·g~(-1)lw)DBDPE(14 ng·g~(-1)lw)HBB、TBBPA和HBCDs(未检出)。鲶鱼和家鸽HFRs组成比较发现,鲶鱼中具有较高百分含量的低溴代PBDE单体和较低的fanti值,而家鸽中具有较高百分含量的高溴代PBDE单体和较高的fanti值。实验结果初步表明,水生生物较多地富集水溶性较大的化合物,陆生生物则较多地富集疏水性较强的化合物。研究认为以上水生和陆生生物体中污染物的差异性富集现象可能与化合物因不同物理化学性质导致的不同环境迁移行为有关。