Biochemische Charakterisierung des Exopolysaccharids von Pediococcus parvulus B399, sowie dessen Hydrolyse durch eine neue beta-1,3-Glucanase aus Delftia sp. MV01

In der vorliegenden Arbeit wurde die erste β-1,3-Glucanase aus Delftia beschrieben. Es konnte gezeigt werden, dass das Enzym unter anderem gegen das nur schwer zu hydrolysierende Exopolysaccharid aus Pediococcus parvulus wirkte. rnrnIm Einzelnen wurde zun��chst das Exopolysaccharid aus Pediococcus parvulus B399 aus einem eigens zusammengestellten β-Glucan-Synthesemedium (Medium M) isoliert und gereinigt. Anschließend erfolgte eine umfassende Charakterisierung des Biopolymers. Hierzu gehörten neben der sauren Hydrolyse zur Bestimmung der Monomerzusammensetzung des Polymers, auch spektroskopische Methoden, darunter 1H und 13C-NMR. Mithilfe der NMR-Spektroskopie konnte die Struktur des Exopolysaccharids aus Pediococcus parvulus B399 bestimmt werden. Es handelte sich hierbei ebenfalls um ein β-1,3(1,2)-Glucan, wie es bereits für Pediococcus parvulus 2.6 beschrieben wurde. Darüber hinaus wurde erstmals ein ATR-FTIR-Spektrum für ein Exopolysaccharid aus Pediokokken gezeigt. Über GPC-Messungen konnte auch die molekulare Größe des β-1,3(1,2)-Glucans aus Pediococcus parvulus B399 bestimmt werden. Es wurde nachgewiesen, dass sich das Exopolysaccharid bei Anzucht in Medium M aus einer hochmolekularen Fraktion (5*106 g/mol) und vier niedermolekularen Fraktionen (347; 818; 10048 und 20836 g/mol) zusammensetzte. Neben der strukturellen Charakterisierung, wurde das Exopolysaccharid auch rheologisch untersucht. Dabei konnte festgestellt werden, dass es sich durch seine schwach gelbildenen Eigenschaften auch zum Einsatz in der Lebensmittelindustrie als Stabilisator, Fettersatzmittel oder ähnliches eignen würde. Die erwähnte gelbildende Netzwerkstruktur konnte für das Exopolysaccharid aus Pediococcus parvulus B399 auch erstmals im AFM bestätigt werden. rnEin weiterer Teil der Arbeit umfasste ein breites Screeningverfahren nach einem geeigneten Organismus, der das Exopolysaccharid aus Pediococcus parvulus B399 effektiv hydrolysieren sollte. Aus einer Anreicherungskultur des Termitendarms (Wenzel et al., 2002), konnte Delftia sp. MV01 isoliert werden. Dieser Organismus produzierte bei Wachstum in β glucanhaltigem Medium (Exopolysaccharid aus Pediococcus parvulus B399, sowie weitere kommerziell erhältliche β-1,3-Glucane) eine Glucanase, die in folgenden Schritten konventionell gereinigt und charakterisiert wurde.

L'inno avestico agli Aməsha Sp��ṇtas (Yasht 2). Testo critico e traduzione con commentario storico religioso

L'inno dedicato ai sette Amesha Sp��ṇta è parte della produzione avestica recenziore, e si compone in gran parte di porzioni testuali riprese da altri testi avestici a loro volta di formazione tardiva. Lo Yašt si divide in tre parti principali: le stanze 0-10; 11-14; e infine la stanza 15 che comprende la formula di chiusura tipica degli inni avestici. La prima sezione (2.0-10) è composta dalla formula di apertura, incompleta rispetto a quelle dei restanti inni, seguita dai primi sette capitoli di entrambi i Sīh-rōzag compresi i Gāh. Le stanze centrali (11-14) si caratterizzano per l'assenza di passi gemelli, un elevato numero di hapax e di arcaismi formali e inoltre, una grande variabilità nella tradizione manoscritta. Si tratta di una formula magica per esorcizzare/allontanare demoni e stregoni, che doveva essere recitata per sette volte. Tale formula probabilmente rappresentava in origine un testo autonomo che veniva recitato assieme ad altri testi avestici. La versione a noi pervenuta comprende la recitazione di parte di entrambi i Sīh-rōzag, ma è molto probabile che tale arrangement sia soltanto una sequenza recitativa che doveva coesistere assieme ad altre. Attualmente la formula magica viene recitata principalmente assieme allo Yasna Haptaŋhāiti, senza le restanti stanze dell'inno nella sua versione geldneriana. Il testo sembra nascere come formula magica la quale venne recitata assieme a diversi testi avestici come per esempio parti dello Sīh-rōzag. In un periodo impossibile da stabilire con certezza la versione viene fissata nella forma a noi pervenuta nella maggior parte dei manoscritti e per la sua affinità formale probabilmente interpretato come inno e perciò incluso nell'innario avestico.

Classification of organisms previously reported as the SP and Stewart-Letscher groups, with descriptions of Necropsobacter gen. nov. and of Necropsobacter rosorum sp. nov. for organisms of the SP group

To allow classification of bacteria previously reported as the SP group and the Stewart-Letscher group, 35 isolates from rodents (21), rabbits (eight), a dog and humans (five) were phenotypically and genotypically characterized. Comparison of partial rpoB sequences showed that 34 of the isolates were closely related, demonstrating at least 97.4 % similarity. 16S rRNA gene sequence comparison of 20 selected isolates confirmed the monophyly of the SP group and revealed 98.5 %-100 % similarity between isolates. A blast search using the 16S rRNA gene sequences showed that the highest similarity outside the SP group was 95.5 % to an unclassified rat isolate. The single strain, P625, representing the Stewart-Letscher group showed the highest 16S rRNA gene similarity (94.9-95.5 %) to members of the SP group. recN gene sequence analysis of 11 representative strains resulted in similarities of 97-100 % among the SP group strains, which showed 80 % sequence similarity to the Stewart-Letscher group strain. Sequence similarity values based on the recN gene, indicative for whole genome similarity, showed the SP group being clearly separated from established genera, whereas the Stewart-Letscher group strain was associated with the SP group. A new genus, Necropsobacter gen. nov., with only one species, Necropsobacter rosorum sp. nov., is proposed to include all members of the SP group. The new genus can be separated from existing genera of the family Pasteurellaceae by at least three phenotypic characters. The most characteristic properties of the new genus are that haemolysis is not observed on bovine blood agar, positive reactions are observed in the porphyrin test, acid is produced from (+)-L-arabinose, (+)-D-xylose, dulcitol, (+)-D-galactose, (+)-D-mannose, maltose and melibiose, and negative reactions are observed for symbiotic growth, urease, ornithine decarboxylase and indole. Previous publications have documented that both ubiquinones and demethylmenaquinone were produced by the proposed type strain of the new genus, Michel A/76(T), and that the major polyamine of representative strains (type strain not included) of the genus is 1,3-diaminopropane, spermidine is present in moderate amounts and putrescine and spermine are detectable only in minor amounts. The major fatty acids of strain Michel A/76(T) are C(14 : 0), C(16 : 0), C(16:1)omega7c and summed feature C(14 : 0) 3-OH/iso-C(16 : 1) I. This fatty acid profile is typical for members of the family Pasteurellaceae. The G+C content of DNA of strain Michel A/76(T) was estimated to be 52.5 mol% in a previous investigation. The type strain is P709(T) ( = Michel A/76(T) = CCUG 28028(T) = CIP 110147(T) = CCM 7802(T)).

Proposal of Bisgaardia hudsonensis gen. nov., sp. nov. and an additional genomospecies, isolated from seals, as new members of the family Pasteurellaceae

Phenotypic and phylogenetic studies were performed on eight Gram-negative-staining, rod-shaped bacteria isolated from seals. Biochemical and physiological studies showed identical profiles for all of the isolates and indicated that they were related to the family Pasteurellaceae. 16S rRNA gene sequencing demonstrated that the organism represented a distinct cluster with two sublines within the family Pasteurellaceae with <96% sequence similarity to any recognized species. Multilocus sequence analysis (MLSA) including rpoB, infB and recN genes further confirmed these findings with the eight isolates forming a genus-like cluster with two branches. Genome relatedness as deduced from recN gene sequences suggested that the isolates represented a new genus with two species. On the basis of the results of the phylogenetic analysis and phenotypic criteria, it is proposed that these bacteria from seals are classified as Bisgaardia hudsonensis gen. nov., sp. nov. (the type species) and Bisgaardia genomospecies 1. The G+C content of the DNA was 39.5 mol%. The type strain of Bisgaardia hudsonensis gen. nov., sp. nov. is M327/99/2(T) (=CCUG 43067(T)=NCTC 13475(T)=98-D-690B(T)) and the reference strain of Bisgaardia genomospecies 1 is M1765/96/5 (=CCUG 59551=NCTC 13474).

Staphylococcus rostri sp. nov., a haemolytic bacterium isolated from the noses of healthy pigs

Twenty coagulase-negative Staphylococcus strains displaying alpha-haemolysis (delta-haemolysin) on sheep-blood agar were isolated from the noses of different pigs in Switzerland. The strains were Gram-stain-positive, non-motile cocci, catalase-positive and coagulase-negative. Sequence analysis of the 16S rRNA gene, sodA, rpoB, dnaJ and hsp60 and phylogenetic characteristics revealed that the strains showed the closest relatedness to Staphylococcus microti CCM 4903(T) and Staphylococcus muscae DSM 7068(T). The strains can be differentiated from S. microti by the absence of mannose fermentation and arginine arylamidase and from S. muscae by the absence of beta-glucuronidase activity and production of alkaline phosphatase. The chosen type strain ARI 262(T) shared 20.1 and 31.9 % DNA relatedness with S. microti DSM 22147(T) and S. muscae CCM 4903(T), respectively, by DNA-DNA hybridization. iso-C(15 : 0), anteiso-C(15 : 0) and iso-C(17 : 0) were the most common fatty acids. Cell-wall structure analysis revealed the peptidoglycan type A3alpha l-Lys-Gly(2)-l-Ser-Gly (type A11.3). The presence of teichoic acid was determined by sequencing the N-acetyl-beta-d-mannosaminyltransferase gene tarA, which is involved in biosynthesis of ribitol teichoic acid. Menaquinone 7 (MK-7) was the predominant respiratory quinone. The G+C content of ARI 262(T) was 38.8 mol%. The isolated strains represent a novel species of the genus Staphylococcus, for which we propose the name Staphylococcus rostri sp. nov. The type strain is ARI 262(T) (=DSM 21968(T) =CCUG 57266(T)) and strain ARI 602 (=DSM 21969 =CCUG 57267) is a reference strain.

Impact of drug-eluting stent selection on long-term clinical outcomes in patients treated for unprotected left main coronary artery disease: the sirolimus vs paclitaxel drug-eluting stent for left main registry (SP-DELFT)

AIM: To compare the long-term relative efficacy and safety of SES and PES in patients undergoing percutaneous coronary intervention (PCI) for unprotected left main coronary artery (ULMCA) disease and to evaluate the role of lesion location and stenting technique in determining outcomes. METHODS AND RESULTS: From April 2002 to April 2004, 288 consecutive patients who underwent elective PCI with DES implantation for de novo lesions on ULMCA have been retrospectively selected and analyzed in seven European and US tertiary care centers. All patients had a minimum follow-up of 3 years. SES was used in 152 patients while 136 received PES. Isolated ostial-shaft disease was present in 27% of patients. Distal LM disease (73%) was treated with single and double stent approach in 29.5% and 43.4% of patients respectively. After 3 years, rates of survival free from any of the events investigated, were independent from lesion location and stenting approach and did not differ significantly between SES and PES groups. Freedom from MACE (SES vs. PES) was 76.3% vs. 83.1% in the ostial/shaft group, 80.3% vs. 72.8% in the distal-single stent group and 67.1% vs. 66.2% in the distal-double stent group. Definite stent thrombosis occurred only in 1(0.3%) patient at 439 days. CONCLUSIONS: In elective patients who underwent PCI for de novo lesions in the ostium, shaft or distal ULMCA, long-term clinical outcomes with SES and PES use were similar independently of lesion location and stenting technique.

Classification of the taxon 2 and taxon 3 complex of Bisgaard within Gallibacterium and description of Gallibacterium melopsittaci sp. nov., Gallibacterium trehalosifermentans sp. nov. and Gallibacterium salpingitidis sp. nov

This investigation was based on 23 isolates from several European countries collected over the past 30 years, and included characterization of all isolates. Published data on amplified fragment length polymorphism typing of isolates representing all biovars as well as protein profiles were used to select strains that were then further characterized by polyamine profiling and sequencing of 16S rRNA, infB, rpoB and recN genes. Comparison of 16S rRNA gene sequences revealed a monophyletic group within the avian 16S rRNA group of the Pasteurellaceae, which currently includes the genera Avibacterium, Gallibacterium and Volucribacter. Five monophyletic subgroups related to Gallibacterium anatis were recognized by 16S rRNA, rpoB, infB and recN gene sequence comparisons. Whole-genome similarity between strains of the five subgroups and the type strain of G. anatis calculated from recN sequences allowed us to classify them within the genus Gallibacterium. In addition, phenotypic data including biochemical traits, protein profiling and polyamine patterns clearly indicated that these taxa are related. Major phenotypic diversity was observed for 16S rRNA gene sequence groups. Furthermore, comparison of whole-genome similarities, phenotypic data and published data on amplified fragment length polymorphism and protein profiling revealed that each of the five groups present unique properties that allow the proposal of three novel species of Gallibacterium, for which we propose the names Gallibacterium melopsittaci sp. nov. (type strain F450(T) =CCUG 36331(T) =CCM 7538(T)), Gallibacterium trehalosifermentans sp. nov. (type strain 52/S3/90(T) =CCUG 55631(T) =CCM 7539(T)) and Gallibacterium salpingitidis sp. nov. (type strain F150(T) =CCUG 15564(T) =CCUG 36325(T) =NCTC 11414(T)), a novel genomospecies 3 of Gallibacterium and an unnamed taxon (group V). An emended description of the genus Gallibacterium is also presented.

Arsenicicoccus dermatophilus sp. nov., a hypha-forming bacterium isolated from the skin of greater flamingos (Phoenicopterus roseus) with pododermatitis

Dermatophilus-like bacteria were observed in histological examinations of samples of diseased foot skin from greater flamingos (Phoenicopterus roseus) living in zoological gardens in Switzerland. When grown on TSA-SB containing polymyxin B, the bacteria isolated from these skin samples formed hyphae, as is typical for Dermatophilus congolensis, but these bacteria were non-haemolytic. The closest relatives based on 16S rRNA gene sequences were the two members of the genus Arsenicicoccus, Arsenicicoccus bolidensis and Arsenicicoccus piscis. A representative of the isolated strains shared 34.3 % DNA-DNA relatedness with the type strain of A. bolidensis, 32.3 % with the type strain of A. piscis and 34.5 % with the type strain of D. congolensis, demonstrating that these strains do not belong to any of these species. The phenotypic characteristics differed from those of members of the genus Arsenicicoccus as well as from those of D. congolensis. The G+C content of strain KM 894/11(T) was 71.6 mol%. The most abundant fatty acids were iso-C15 : 0, summed feature 3 (including C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C18 : 1ω9c. MK-8(H4) was the predominant menaquinone. Cell-wall structure analysis revealed that the peptidoglycan type was A3γ ll-Dpm-Gly (type A41.1). Based on genotypic and chemotaxonomic characteristics, the isolated strains represent a novel species within the genus Arsenicicoccus, for which the name Arsenicicoccus dermatophilus sp. nov. is proposed. The type strain is KM 894/11(T) ( = DSM 25571(T) = CCUG 62181(T) = CCOS 690(T)), and strain KM 1/12 ( = DSM 25572 = CCUG 62182 = CCOS 691) is a reference strain.

Solute transport in crystalline rocks at Äsp�� — II: Blind predictions, inverse modelling and lessons learnt from test STT1

Based on the results from detailed structural and petrological characterisation and on up-scaled laboratory values for sorption and diffusion, blind predictions were made for the STT1 dipole tracer test performed in the Swedish A¨ spo¨ Hard Rock Laboratory. The tracers used were nonsorbing, such as uranine and tritiated water, weakly sorbing 22Na+, 85Sr2 +, 47Ca2 +and more strongly sorbing 86Rb+, 133Ba2 +, 137Cs+. Our model consists of two parts: (1) a flow part based on a 2D-streamtube formalism accounting for the natural background flow field and with an underlying homogeneous and isotropic transmissivity field and (2) a transport part in terms of the dual porosity medium approach which is linked to the flow part by the flow porosity. The calibration of the model was done using the data from one single uranine breakthrough (PDT3). The study clearly showed that matrix diffusion into a highly porous material, fault gouge, had to be included in our model evidenced by the characteristic shape of the breakthrough curve and in line with geological observations. After the disclosure of the measurements, it turned out that, in spite of the simplicity of our model, the prediction for the nonsorbing and weakly sorbing tracers was fairly good. The blind prediction for the more strongly sorbing tracers was in general less accurate. The reason for the good predictions is deemed to be the result of the choice of a model structure strongly based on geological observation. The breakthrough curves were inversely modelled to determine in situ values for the transport parameters and to draw consequences on the model structure applied. For good fits, only one additional fracture family in contact with cataclasite had to be taken into account, but no new transport mechanisms had to be invoked. The in situ values for the effective diffusion coefficient for fault gouge are a factor of 2–15 larger than the laboratory data. For cataclasite, both data sets have values comparable to laboratory data. The extracted Kd values for the weakly sorbing tracers are larger than Swedish laboratory data by a factor of 25–60, but agree within a factor of 3–5 for the more strongly sorbing nuclides. The reason for the inconsistency concerning Kds is the use of fresh granite in the laboratory studies, whereas tracers in the field experiments interact only with fracture fault gouge and to a lesser extent with cataclasite both being mineralogically very different (e.g. clay-bearing) from the intact wall rock.

Uruburuella testudinis sp. nov., isolated from tortoise (Testudo)

A polyphasic taxonomic analysis was carried out on 11 uncommon Gram-stain-negative, non-motile, catalase- and oxidase-positive, but indole-negative, bacterial strains isolated from tortoises. Phenotypically and genetically they represented a homogeneous group of organisms most closely related to, but distinct from, Uruburuella suis. In a reconstructed 16S rRNA gene tree they clustered on a monophyletic branch next to U. suis with gene similarities between strains of 99.5-100%, and of up to 98.2% with U. suis . DNA-DNA hybridization indicated the organisms represented a novel species with only 40% DNA-DNA similarity with U. suis . Partial sequencing of rpoB resulted in two subclusters confirming the 16S rRNA gene phylogeny; both genes allowed clear separation and identification of the novel species. Furthermore, they could be unambiguously identified by matrix-assisted laser desorption ionization time-of-flight MS, where, again, they formed a highly homogeneous cluster separate from U. suis and other members of the family Neisseriaceae . The major fatty acids were C(16 : 0) and summed feature C(16 : 1)ω7c/iso-C(15 : 0) 2-OH. The DNA G+C content was 54.4 mol%. Based on phenotypic and genetic data we propose classifying these organisms as representatives of a novel species named Uruburuella testudinis sp. nov. The type strain is 07_OD624(T) ( = DSM 26510(T) = CCUG 63373(T)).

Role of a ribosomal RNA phosphate oxygen during the EF-G-triggered hydrolysis

Elongation factor-catalyzed GTP hydrolysis is a key reaction during the ribosomal elongation cycle. Recent crystal structures of G proteins, such as elongation factor G (EF-G) bound to the ribosome, as well as many biochemical studies, provide evidence that the direct interaction of translational GTPases (trGTPases) with the sarcin-ricin loop (SRL) of ribosomal RNA (rRNA) is pivotal for hydrolysis. However, the precise mechanism remains elusive and is intensively debated. Based on the close proximity of the phosphate oxygen of A2662 of the SRL to the supposedly catalytic histidine of EF-G (His87), we probed this interaction by an atomic mutagenesis approach. We individually replaced either of the two nonbridging phosphate oxygens at A2662 with a methyl group by the introduction of a methylphosphonate instead of the natural phosphate in fully functional, reconstituted bacterial ribosomes. Our major finding was that only one of the two resulting diastereomers, the SP methylphosphonate, was compatible with efficient GTPase activation on EF-G. The same trend was observed for a second trGTPase, namely EF4 (LepA). In addition, we provide evidence that the negative charge of the A2662 phosphate group must be retained for uncompromised activity in GTP hydrolysis. (1) In summary, our data strongly corroborate that the nonbridging proSP phosphate oxygen at the A2662 of the SRL is critically involved in the activation of GTP hydrolysis. A mechanistic scenario is supported in which positioning of the catalytically active, protonated His87 through electrostatic interactions with the A2662 phosphate group and H-bond networks are key features of ribosome-triggered activation of trGTPases.

Role of a ribosomal RNA phosphate oxygen during the EF-G-triggered hydrolysis

Elongation factor-catalyzed GTP hydrolysis is a key reaction during the ribosomal elongation cycle. Recent crystal structures of G proteins, such as elongation factor G (EF-G) bound to the ribosome, as well as many biochemical studies, provide evidence that the direct interaction of translational GTPases (trGTPases) with the sarcin-ricin loop (SRL) of ribosomal RNA (rRNA) is pivotal for hydrolysis. However, the precise mechanism remains elusive and is intensively debated. Based on the close proximity of the phosphate oxygen of A2662 of the SRL to the supposedly catalytic histidine of EF-G (His87), we probed this interaction by an atomic mutagenesis approach. We individually replaced either of the two nonbridging phosphate oxygens at A2662 with a methyl group by the introduction of a methylphosphonate instead of the natural phosphate in fully functional, reconstituted bacterial ribosomes. Our major finding was that only one of the two resulting diastereomers, the SP methylphosphonate, was compatible with efficient GTPase activation on EF-G. The same trend was observed for a second trGTPase, namely EF4 (LepA). In addition, we provide evidence that the negative charge of the A2662 phosphate group must be retained for uncompromised activity in GTP hydrolysis. (1) In summary, our data strongly corroborate that the nonbridging proSP phosphate oxygen at the A2662 of the SRL is critically involved in the activation of GTP hydrolysis. A mechanistic scenario is supported in which positioning of the catalytically active, protonated His87 through electrostatic interactions with the A2662 phosphate group and H-bond networks are key features of ribosome-triggered activation of trGTPases.

Design, synthesis and cellular and molecular pharmacology of 2$\sp\prime$-bromo-4$\sp\prime$-epidaunorubicin (WP401): A novel non-cross-resistant anthracycline antibiotic with the intrinsic ability to circumvent P -glycoprotein-mediated drug resistance

We designed and synthesized a novel daunorubicin (DNR) analogue that effectively circumvents P-glycoprotein (P-gp)-mediated drug resistance. The fully protected carbohydrate intermediate 1,2-dibromoacosamine was prepared from acosamine and effectively coupled to daunomycinone in high yield. Deprotection under alkaline conditions yielded 2$\sp\prime$-bromo-4$\sp\prime$-epidaunorubicin (WP401). The in vitro cytotoxicity and cellular and molecular pharmacology of WP401 were compared with those of DNR in a panel of wild-type cell lines (KB-3-1, P388S, and HL60S) and their multidrug-resistant (MDR) counterparts (KB-V1, P388/DOX, and HL60/DOX). Fluorescent spectrophotometry, flow cytometry, and confocal laser scanning microscopy were used to measure intracellular accumulation, retention, and subcellular distribution of these agents. All MDR cell lines exhibited reduced DNR uptake that was restored, upon incubation with either verapamil (VER) or cyclosporin A (CSA), to the level found in sensitive cell lines. In contrast, the uptake of WP401 was essentially the same in the absence or presence of VER or CSA in all tested cell lines. The in vitro cytotoxicity of WP401 was similar to that of DNR in the sensitive cell lines but significantly higher in resistant cell lines (resistance index (RI) of 2-6 for WP401 vs 75-85 for DNR). To ascertain whether drug-mediated cytotoxicity and retention were accompanied by DNA strand breaks, DNA single- and double-strand breaks were assessed by alkaline elution. High levels of such breaks were obtained using 0.1-2 $\mu$g/mL of WP401 in both sensitive and resistant cells. In contrast, DNR caused strand breaks only in sensitive cells and not much in resistant cells. We also compared drug-induced DNA fragmentation similar to that induced by DNR. However, in P-gp-positive cells, WP401 induced 2- to 5-fold more DNA fragmentation than DNR. This increased DNA strand breakage by WP401 was correlated with its increased uptake and cytotoxicity in these cell lines. Overall these results indicate that WP401 is more cytotoxic than DNR in MDR cells and that this phenomenon might be related to the reduced basicity of the amino group and increased lipophilicity of WP401. ^

Abundance of Cnidaria and Ctenophora taxa in the North Atlantic sampled during the G. O. Sars Cruise in May 2013

In recent years a global increase in jellyfish (i.e. Cnidarians and Ctenophores) abundance and a rise in the recurrence of jellyfish outbreak events have been largely debated, but a general consensus on this matter has not been achieved yet. Within this debate, it has been generally recognized that there is a lack of reliable data that could be analyzed and compared to clarify whether indeed jellyfish are increasing throughout the world ocean as a consequence of anthropogenic impact and hydroclimatic variability. During the G.O. Sars cruise jellyfish were collected at different depths in the 0-1000m layer using a standard 1 m**2 Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) (quantitative data), Harstad and macroplankton trawls (qualitative data). The comparison of records collected with different nets during the G.O. Sars transatlantic cruise shows that different sampling gears might provide very different information on jellyfish diversity. Indeed, the big trawls mostly collect relatively large scyphozoan and hydrozoan species such as Atolla, Pelagia, Praya, Vogtia, while small hydrozoans (e.g. Clytia, Gilia, Muggiaea) and early stages of ctenophora are only caught by the smaller nets.