Characteristics of marine aggregates during the phytoplankton spring bloom in a temperate tidal basin

High abundance of aggregates has often been related to high primary production and phytoplankton blooms. Especially in shallow and turbid coastal regions the formation of aggregates and their sinking velocities also depends on the interaction between primary produced organic matter and lithogenic particles. Nine roller tank experiments were conducted during spring 2012 in the Northern Wadden Sea (Germany) to determine temporal dynamics of formation, composition, and sinking velocity of aggregates, in relation to the wax and wane of the phytoplankton bloom. Highest sinking velocities (June-July) did not coincide with highest SPM concentrations (January-March). After the diatom bloom almost 80% of SPM was rapidly settling in aggregates but only 10% rapidly settled during the subsequent Phaeocystis bloom. The results suggest interactive effects of particle size, specific density and the availability of organic and inorganic particulate matter. Our study underlines the importance of marine aggregates as carrier of organic matter and of lithogenic particles as ballasting material for sedimentation in tidal basins

707PSAFETY AND EFFICACY OF NEOADJUVANT FOLFIRINOX IN PATIENTS (PTS) WITH LOCALLY ADVANCED PANCREATIC ADENOCARCINOMA (LAPC)

Abstract Aim: In a retrospective study of 18 pts with unresectable (UR) or borderline resectable (BR) LAPC, neoadjuvant therapy with FOLFIRINOX with or without subsequent chemoradiation (CCRT) resulted in an R0 resection rate (RR) of 44% (Hosein et al, BMC Cancer 2012). The reported 1-year progression-free survival (PFS) was 83 % and the 1-year overall survival (OS) was 100 %. Toxicity profile was tolerable. In order to confirm these preliminary results, we analyzed a large cohort of pts treated in a similar fashion with mature follow-up. Methods: Between 2008 and 2013, 51 treatment-naïve pts with LAPC were treated with first-line FOLFIRINOX with neoadjuvant intent. Pts were categorized as BR or UR using the NCCN criteria. Pts received FOLFIRINOX chemotherapy (at the full dose as described in the ACCORD-11 trial) until maximum response or tolerability, and then underwent surgery if their imaging suggested resectability. Pts then received CCRT if they were still UR or BR after FOLFIRINOX. The end points of this retrospective analysis were OS, PFS, R0 RR and toxicity profile. Results: A total of 429 cycles were given with a median of 8 (range 2-29); 27 (53%) went on to receive CCRT. After a median follow-up of 17 mo (range 2-56), the Kaplan-Meier median OS was 35 mo (95% CI 26-45), the 3-yr OS rate was 42% and the median PFS was 14 mo (95% CI 11 – 16). By imaging criteria, 13 (26%) were converted to resectability and 10 (4 BR and 6 UR) of these had successful R0 resections. Pts who had R0 resections had a significantly longer survival than pts who did not (3-yr OS rate 67% vs 21%, log rank p = 0.042). Grade 1&2/3&4 chemotherapy-related toxicities were neutropenia (39%/20%), neutropenic fever (0%/12%), thrombocytopenia (53%/16%), anemia (63%/10%), fatigue (76%/6%), nausea (57%/4%) vomiting (22%/4%), neuropathy (53%/4%) and diarrhea (37%/10%). Conclusions: FOLFIRINOX followed by chemoradiotherapy is feasible as neoadjuvant therapy in patients with unresectable LAPC. Although the resection rate was only 20%, the median OS of almost 3 years is appreciably longer than historical survival rates for this population. Prospective controlled trials testing this algorithm in LAPC are ongoing. Disclosure: All authors have declared no conflicts of interest

Considerations and consequences of allowing DNA sequence data as types of fungal taxa

Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.Peer reviewe