Seagrass biofilm communities at a naturally CO2-rich vent

Seagrass meadows are a crucial component of tropical marine reef ecosystems. Seagrass plants are colonized by a multitude of epiphytic organisms that contribute to broadening the ecological role of seagrasses. To better understand how environmental changes like ocean acidification might affect epiphytic assemblages, the microbial community composition of the epiphytic biofilm of Enhalus acroides was investigated at a natural CO2 vent in Papua New Guinea using molecular fingerprinting and next generation sequencing of 16S and 18S rRNA genes. Both bacterial and eukaryotic epiphytes formed distinct communities at the CO2-impacted site compared to the control site. This site-related CO2 effect was also visible in the succession pattern of microbial epiphytes. We further found an increased abundance of bacterial types associated with coral diseases at the CO2-impacted site (Fusobacteria, Thalassomonas) whereas eukaryotes such as certain crustose coralline algae commonly related to healthy reefs were less diverse. These trends in the epiphytic community of E. acroides suggest a potential role of seagrasses as vectors of coral pathogens and may support previous predictions of a decrease in reef health and prevalence of diseases under future ocean acidification scenarios

Effects of Thermal Stress on the Gut Microbiome of Juvenile Milkfish (Chanos chanos)

Milkfish, an important aquaculture species in Asian countries, are traditionally cultured in outdoor-based systems. There, they experience potentially stressful fluctuations in environmental conditions, such as temperature, eliciting changes in fish physiology. While the importance of the gut microbiome for the welfare and performance of fish has been recognized, little is known about the effects of thermal stress on the gut microbiome of milkfish and its interactions with the host's metabolism. We investigated the gut microbiome of juvenile milkfish in a thermal stress experiment, comparing control (26 degrees C) and elevated temperature (33 degrees C) treatments over three weeks, analyzing physiological biomarkers, gut microbiome composition, and tank water microbial communities using 16S amplicon sequencing. The gut microbiome was distinct from the tank water and dominated by Cetobacterium, Enterovibrio, and Vibrio. We observed a parallel succession in both temperature treatments, with microbial communities at 33 degrees C differing more strongly from the control after the initial temperature increase and becoming more similar towards the end of the experiment. As proxy for the fish's energy status, HSI (hepatosomatic index) was correlated with gut microbiome composition. Our study showed that thermal stress induced changes in the milkfish gut microbiome, which may contribute to the host's habituation to elevated temperatures over time

Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating the C60-C8H8 cocrystal with green or blue light a photochemical reaction was observed leading to a similar product to that of the thermal polymerization.Comment: 26 pages, 8 figures, to appear in Journal of Physical Chemistry B 2nd version: minor changes in wording, accepted version by journa

Synthesis and properties of Fischer carbene complexes of N,N-dimethylaniline and anisole π-coordinated to chromium tricarbonyl

Please read abstract in the article.Associated content: Accession codes: CCDC 1577569, CCDC 1577570, CCDC 1577571, CCDC 1577572, CCDC 1577573, CCDC 1577574 and CCDC 1577575 contains the supplementary crystallographic data for this paper. This data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data [email protected], or by contacting The Cambridge Crystallographic Data Center, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.SL acknowledges the Alexander von Humboldt Foundation and University of Pretoria for funding of a research visit in Konstanz and the NRF for financial support of the project by GUN 87788 and 95772 grants. NW and SL kindly acknowledge the LC-MS Synapt Facility (Department of Chemistry, University of Pretoria) for mass spectrometry services provided by Ms Madelien Wooding and some help in obtaining NMR spectra by Ms Zandria Lamprecht. NW gratefully acknowledges financial support by the University of Pretoria and the NRF for a research visit to the Universität Konstanz and to Prof. Winter for hosting her on two occasions. RFW thanks the state of Baden-Württemberg, Germany, for providing access to the bwHPC computational facilities at the Karlsruhe Institute of Technology.http://www.elsevier.com/locate/jorganchem2019-08-15hj2019Chemistr

Seagrass biofilm communities at a naturally CO2-rich vent at Papua New Guinea

Seagrass meadows are a crucial component of tropical marine reef ecosystems. The seagrass plants are colonized by a multitude of epiphytic organisms that contribute to determining the ecological role of seagrasses. To better understand how environmental changes like ocean acidification might affect epiphytic assemblages, the microbial community composition of the epiphytic biofilm of Enhalus acroides was investigated at a natural CO2 vent in Papua New Guinea using molecular fingerprinting and next generation sequencing of 16S and 18S rRNA genes. Both bacterial and eukaryotic epiphytes formed distinct communities at the CO2-impacted site compared to the control site. This site-related CO2 effect was also visible in the succession pattern of microbial epiphytes. We further found an increased abundance of bacterial types associated with coral diseases at the CO2-impacted site (Fusobacteria, Thalassomonas) whereas eukaryotes such as certain crustose coralline algae commonly related to healthy reefs were less diverse. These trends in the epiphytic community of E. acroides suggest a potential role of seagrasses as vectors of coral pathogens and may support previous predictions of a decrease in reef health and prevalence of diseases under future ocean acidification scenarios

Bacterial Community Composition and Potential Driving Factors in Different Reef Habitats of the Spermonde Archipelago, Indonesia

Coastal eutrophication is a key driver of shifts in bacterial communities on coral reefs. With fringing and patch reefs at varying distances from the coast the Spermonde Archipelago in southern Sulawesi, Indonesia offers ideal conditions to study the effects of coastal eutrophication along a spatially defined gradient. The present study investigated bacterial community composition of three coral reef habitats: the water column, sediments, and mucus of the hard coral genus Fungia, along that cross shelf environmental and water quality gradient. The main research questions were: (1) How do water quality and bacterial community composition change along a coastal shelf gradient? (2) Which water quality parameters influence bacterial community composition? (3) Is there a difference in bacterial community composition among the investigated habitats? For this purpose, a range of key water parameters were measured at eight stations in distances from 2 to 55 km from urban Makassar. This was supplemented by sampling of bacterial communities of important microbial habitats using 454 pyrosequencing. Findings revealed that the population center Makassar had a strong effect on the concentrations of Chlorophyll a, suspended particulate matter (SPM), and transparent exopolymer particles (TEP), which were all significantly elevated at the inshore compared the other seven sites. Shifts in the bacterial communities were specific to each sampled habitat. Two OTUs, belonging to the genera Escherichia/Shigella (Gammaproteobacteria) and Raistonia (Betaproteobacteria), respectively, both dominated the bacterial community composition of the both size fractions of the water column and coral mucus. The sampled reef sediments were more diverse, and no single OTUs was dominant. There was no gradual shift in bacterial classes or OTUs within the sampled habitats. In addition, we observed very distinct communities between the investigated habitats. Our data show strong changes in the bacterial community composition at the inshore site for water column and sediment samples. Alarmingly, there was generally a high prevalence of potentially pathogenic bacteria across the entire gradient

Recovering short DNA fragments from minerals and marine sediments: A comparative study evaluating lysis and isolation approaches

Publication status: PublishedAbstractMarine sediments as excellent climate archives, contain among other biomolecules substantial amounts of extracellular DNA. Through mineral binding, some of the DNA remains protected from degradation which aids its preservation. While this pool of DNA represents genomic ecosystem fingerprints spanning over millions of years, the capability of current DNA extraction methods in recovering mineral‐bound DNA remains poorly understood. We evaluated current sedimentary DNA extraction approaches and their ability to recover short DNA fragments from artificially created DNA‐mineral complexes involving pure clay minerals or quartz, as well as from different types of natural marine sediments. We separately investigated lysis (DNA release) and isolation steps (purification of DNA) comparing five different lysis buffers across two commonly used DNA isolation approaches: silica magnetic beads and liquid‐phase organic extraction and purification. The choice of lysis buffer significantly impacted the amount of recovered mineral‐bound DNA and facilitated selective desorption of DNA fragments. High molarity EDTA and phosphate lysis buffers recovered on average an order of magnitude more DNA from clay minerals than other tested buffers, while both isolation approaches recovered comparable amounts of DNA. In marine sediments, however, liquid‐phase organic extraction caused inhibitory effects in subsequent downstream applications (e.g., PCR), across all assessed DNA extracts, while silica magnetic beads induced inhibition only in half of the tested DNA extracts. Thus, the isolation approach, together with the lysis buffer, played a decisive role in successful library preparation with lysis buffer choice ultimately impacting final library fragment distribution. With this study, we underscore the critical importance of lysis buffer selection to maximize the recovery of mineral‐bound DNA and show its profound impact on recovered fragment lengths in sedimentary DNA extractions, a crucial factor alongside existing isolation approaches in facilitating high‐quality DNA extracts for downstream analysis related to ancient environmental DNA research.</jats:p