Marine sedimentary ancient DNA (sedaDNA) is increasingly used to study past ocean ecosystems, however, studies have been severely limited by the very low amounts of DNA preserved in the subseafloor, ...and the lack of bioinformatic tools to authenticate sedaDNA in metagenomic data. We applied a hybridisation capture 'baits' technique to target marine eukaryote sedaDNA (specifically, phyto- and zooplankton, 'Planktonbaits1'; and harmful algal bloom taxa, 'HABbaits1'), which resulted in up to 4- and 9-fold increases, respectively, in the relative abundance of eukaryotes compared to shotgun sequencing. We further used the bioinformatic tool 'HOPS' to authenticate the sedaDNA component, establishing a new proxy to assess sedaDNA authenticity, "% eukaryote sedaDNA damage", that is positively correlated with subseafloor depth. We used this proxy to report the first-ever DNA damage profiles from a marine phytoplankton species, the ubiquitous coccolithophore Emiliania huxleyi. Our approach opens new avenues for the detailed investigation of long-term change and evolution of marine eukaryotes over geological timescales.
Seafood comprising of both vertebrate and invertebrate aquatic organisms are nutritious, rich in omega-3 fatty acids, essential vitamins, proteins, minerals and form part of healthy diet. However, ...despite the health and nutritional benefits, seafood is highly perishable. Spoilage of seafood could be as a result of microbial activity, autolysis or chemical oxidation. Microbial activity constitutes more spoilage than others. Spoilage bacteria are commonly Gram negative and produce off odours and flavours in seafood as a result of their metabolic activities. Storage temperature, handling and packaging conditions affect microbial growth and thus the shelf-life of seafood. Due to the complexity of the microbial communities in seafood, culture dependent methods of detection may not be useful, hence the need for culture independent methods are necessary to understand the diversity of microbiota and spoilage process. Similarly, the volatile organic compounds released by spoilage bacteria are not fully understood in some seafood. This review therefore highlights current knowledge and understanding of seafood spoilage microbiota, volatile organic compounds, effects of storage temperature and packaging conditions on quality of seafood.
•Spoilage microbiota in seafood•Complexity of spoilage microbial communities in seafood•Effects of storage temperature and packaging conditions on quality of seafood•Diversity of volatile organic compounds produced by seafood spoilage bacteria
Increasing scientific awareness since the 1980s of the chain-forming dinoflagellate
Gymnodinium catenatum has led to this species being reported with increased frequency in a globally increasing ...number of countries (23 at present).
G. catenatum exhibits little molecular genetic variation in rDNA over its global range, in contrast to RAPD fingerprinting which points to high genetic variation within regional populations even between estuaries 50
km apart. All Australian and New Zealand strains possess a thymine nucleotide (T-gene) near the start of the 5.8S rRNA whereas all other global populations examined to date possess cytosine-nucleotide (C-gene), except for southern Japan which harbours both C-gene and T-gene strains. Together with cyst and plankton evidence this strongly suggests that both Australian and New Zealand populations have derived from southern Japan. Global dinoflagellate populations and cultures exhibit an extraordinary variation in PST profiles (STX and 21 analogues), but consistent regional patterns are evident with regard to the production of C1,2; C3,4; B1,2; and neoSTX analogues. PST profiles of cyst-derived cultures are deemed unrepresentative. Distinct ecophysiological differences exist between tropical (21–32
°C) and warm-temperate ecotypes (12–18
°C), but these appear unrelated to ITS genotypes and PST toxin phenotypes. On current evidence, cyst germination appears to play a minimal role in the bloom dynamics of this species, while seasonal and inter-annual bloom variations result from the physical constraints (temperature and light) on the growth of the dinoflagellates in the water column.
G. catenatum exhibits a capacity to utilize many forms of nitrogen. Its chain formation and strong motility allow it to undergo retrieval migrations to exploit light and nutrient resource gradients in both stratified and mixed environments. Subtle strain-level variations in micronutrient (Se, humics) requirements and interaction with associated bacterial flora may provide a partial explanation for the contrasting inshore (Tasmanian), and offshore (Spain, Mexico) bloom patterns by the same species in different geographic regions.
SRTR uses data collected by OPTN to calculate metrics such as donation/conversion rate, organ yield, and rate of organs recovered for transplant but not transplanted. In 2015, 1,072,828 death and ...imminent death referrals were made to Organ Procurement Organizations, of which 21,559 met the definition of eligible (9793) or imminent (11,766) deaths per OPTN policy. The number of deceased donors was 9080, and this number has been increasing since 2010. The number of organs authorized for recovery increased slightly to 65,086 in 2015, and the number recovered increased slightly to 25,762. In 2015, 4370 organs were discarded, including 3157 kidneys, 311 pancreata, 703 livers, 30 hearts, and 214 lungs. These numbers suggest a need to reduce the number of organs discarded.
Some diatoms belonging to the genus Pseudo-nitzschia produce the neurotoxin domoic acid (DA), which causes amnesic shellfish poisoning (ASP). In Europe, accumulation of da in shellfish has led to ...shellfish harvesting closures in western Scottish waters since 1999. However, little is yet known of the temporal appearance and succession of Pseudo-nitzschia species and how this may relate to environmental forcing. A phytoplankton monitoring programme was established for almost 3 yr at a coastal station in western Scottish waters to study the diversity and seasonal variation of Pseudo-nitzschia species in relation to physical and chemical parameters of the water column. Samples were collected with a high temporal resolution. Annually repeatable seasonal patterns of Pseudo-nitzschia abundance were evident. Pseudo-nitzschia cells were categorised by shape and size into 2 groups, the 'delicatissima-group' and the 'seriata-group'. Cluster analysis demonstrated the different dynamics of the 2 Pseudo-nitzschia groups. The delicatissima-group was dominated in spring by non-toxic P. delicatissima, while the seriata-group occurred mainly during the summer months. Summer to autumn blooms of both groups were composed of several species, including toxic P. australis and P. seriata and potentially toxic P. pseudo-delicatissima. Redundancy analysis indicated that 31% of the variance in Pseudo-nitzschia spp. abundance could be explained by the measured environmental variables. The repeatable annual nature of the blooms suggests that deterministic forecasting of the timing of future toxic Pseudo-nitzschia spp. events may be an achievable goal.
Deceased Organ Donation Israni, A. K.; Zaun, D.; Bolch, C. ...
American journal of transplantation,
January 2016, 2016-Jan, 2016-01-00, 20160101, Letnik:
16, Številka:
S2
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
SRTR uses data collected by OPTN to calculate metrics such as donation/conversion rate, organ yield, and rate of organs recovered for transplant but not transplanted. In 2014, 9252 eligible ...deaths were reported by organ procurement organizations, a slight increase from 8944 in 2012, and the donation/conversation rate was 73.4 eligible donors per 100 eligible deaths, a slight increase from 71.3 in 2013. Some metrics show variation across organ procurement organizations, suggesting that sharing best practices could lead to gains in efficiency and organ retrieval.
Pseudo-nitzschia seriata (Cleve) H. Peragallo isolated from Scottish west coast waters was studied in batch culture with phosphate (P) or silicate (Si) as the yield-limiting nutrient at 15 degree C. ...This species produced the neurotoxin domoic acid (DA) when either nutrient was limiting but produced more when stressed by Si limitation during the stationary phase. Under P-limiting conditions, exponential growth stopped after P was reduced to a low threshold concentration. Under Si-limiting conditions, fast exponential growth was followed by a period of slower exponential growth, until Si became exhausted. A stationary phase was observed in the P-limited but not the Si-limited cultures, the latter showing a rapid decrease in cell density after the second exponential growth phase. Si-limited cultures exhibited a further period of active metabolism (as indicated by increases in chl and carbon per cell) late in the experiment, presumably fueled by regenerated Si. DA production was low in exponential phase under both conditions. In P-limited cultures, most DA was produced during the immediate postexponential phase, with little or no new DA produced during later cell senescence. In contrast, although a substantial amount of DA was produced during the slower exponential phase of the Si-limited cultures, DA production was even greater near the end of the experiment, coincident with the period of chl synthesis and increase in carbon biomass. Comparison of the magnitude of toxin production in the two nutrient regimes indicated a greater threat of P. seriata-generated amnesic shellfish poisoning events under Si rather than P nutrient limitation.
A method for separating and concentrating living dinoflagellate cysts from marine sediments, using aqueous solutions of the nontoxic chemical sodium polytungstate (SPT), is described. A two-phase, ...step gradient composed of an upper phase of filtered seawater and a lower phase of aqueous SPT with a specific gravity of 1.30 g cm
−3
efficiently separates inorganic particles and organic detritus, retaining living dinoflagellate cysts and intact pollen grains at the phase interface. A consistently higher number of cyst species were identified in treated samples compared to size-fractionated and panned samples, and recovery of living cysts was in excess of 80% of those present in the original sample. Step gradients prepared from SPT have the advantage of a lower viscosity and the potential of higher maximum specific gravities, providing flexibility in the preparation of gradients and selective recovery of live material. The proposed method is rapid (20-30 min), inexpensive, and effective, improving the percentage of living/empty cysts from as little as 4% to as much as 82%. No detectable or selective mortality of particular groups was evident, and 25 species of dinoflagellate were successfully germinated from treated samples, including those of the toxic species
Gymnodinium catenatum
Graham and
Alexandrium catenella
(Whedon et Kofoid) Balech. The methods described here present substantial improvements in the time required for and the detection limits of surveys for cysts of toxic dinoflagellates.
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