Optimal culture conditions for the propagation of the oyster pathogen Perkinsus marinus (Apicomplexa) in protein deficient medium

The protozoan, Perkinsus marinus, acclimated and proliferated in the culture medium JL-ODRP-1 without bovine serum albumin. The principal culture conditions for the optimal propagation of P. marinus in this protein deficient culture medium, were determined. The greatest growth rates of the parasite occurred at 28 degrees C, 661 mOsm/kg and pH 7.5. Decreasing seeding densities from 16 x 10(5) to 1 x 10(5) also increased growth rate. After several passages in the absence of 5% CO2 tension, the growth rate of P. marinus was similar to its original value in the presence of 5% CO2 tension. This protein deficient culture medium is ideally suited to study parasite-derived proteins since P. marinus extracellular proteins in culture supernatants were produced and were easily detected by gel electrophoresis and silver staining

Development of a protein-free chemically defined culture medium for the propagation of the oyster pathogen Perkinsus marinus

In the present study we describe a protein-free, chemically defined culture medium, designated JL-ODRP-3, which supports the propagation of Perkinsus marinus, a parasite of the eastern oyster, Crassotrea virginica. P. marinus adapted rapidly to the defined medium and the growth rate of the protozoan increased significantly following a few subcultures. Two isolates of P. marinus, one from the Chesapeake Bay (Virginia) and the other from the Gulf of Mexico (Texas) were cultured for at least ten passes. The doubling times far the isolates from Virginia and Texas, in Jog phase, were 18 +/- 1.2 and 28.6 +/- 3.2 hours respectively, after ten passes in JL-ODRP-3. Moreover, P. marinus cells cultured in the defined medium were infective to eastern oysters. Finally, the defined medium was used successfully to initiate continuous cultures of P. marinus from heart fragments of infected oysters. The absence of proteins and peptides from this chemically defined medium demarcates JL-ODRP-3 as the most suitable medium to study P. marinus proteins, to produce antigens far antibody production, and to screen chemotherapeutic agents

Multipartite entanglement percolation

We present percolation strategies based on multipartite measurements to propagate entanglement in quantum networks. We consider networks spanned on regular lattices whose bonds correspond to pure but non-maximally entangled pairs of qubits, with any quantum operation allowed at the nodes. Despite significant effort in the past, improvements over naive (classical) percolation strategies have been found for only few lattices, often with restrictions on the initial amount of entanglement in the bonds. In contrast, multipartite entanglement percolation outperform the classical percolation protocols, as well as all previously known quantum ones, over the entire range of initial entanglement and for every lattice that we considered.Comment: revtex4, 4 page

Enhancement of Entanglement Percolation in Quantum Networks via Lattice Transformations

We study strategies for establishing long-distance entanglement in quantum networks. Specifically, we consider networks consisting of regular lattices of nodes, in which the nearest neighbors share a pure, but non-maximally entangled pair of qubits. We look for strategies that use local operations and classical communication. We compare the classical entanglement percolation protocol, in which every network connection is converted with a certain probability to a singlet, with protocols in which classical entanglement percolation is preceded by measurements designed to transform the lattice structure in a way that enhances entanglement percolation. We analyze five examples of such comparisons between protocols and point out certain rules and regularities in their performance as a function of degree of entanglement and choice of operations.Comment: 12 pages, 17 figures, revtex4. changes from v3: minor stylistic changes for journal reviewer, minor changes to figures for journal edito

Distribution of entanglement in networks of bi-partite full-rank mixed states

We study quantum entanglement distribution on networks with full-rank bi-partite mixed states linking qubits on nodes. In particular, we use entanglement swapping and purification to partially entangle widely separated nodes. The simplest method consists of performing entanglement swappings along the shortest chain of links connecting the two nodes. However, we show that this method may be improved upon by choosing a protocol with a specific ordering of swappings and purifications. A priori, the design that produces optimal improvement is not clear. However, we parametrize the choices and find that the optimal values depend strongly on the desired measure of improvement. As an initial application, we apply the new improved protocols to the Erd\"os--R\'enyi network and obtain results including low density limits and an exact calculation of the average entanglement gained at the critical point.Comment: 15 pages, 19 figures. New version includes improvements suggested in referee repor

Large-scale variation in wave attenuation of oyster reef living shorelines and the influence of inundation duration

One of the paramount goals of oyster reef living shorelines is to achieve sustained and adaptive coastal protection, which requires meeting ecological (i.e., develop a self-sustaining oyster population) and engineering (i.e., provide coastal defense) targets. In a large-scale comparison along the Atlantic and Gulf coasts of the United States, the efficacy of various designs of oyster reef living shorelines at providing wave attenuation was evaluated accounting for the ecological limitations of oysters with regards to inundation duration. A critical threshold for intertidal oyster reef establishment is 50% inundation duration. Living shorelines that spent less than half of the time (\u3c 50%) inundated were not considered suitable habitat for oysters, however, were effective at wave attenuation (68% reduction in wave height). Reefs that experienced \u3e 50% inundation were considered suitable habitat for oysters, but wave attenuation was similar to controls (no reef; ~5% reduction in wave height). Many of the oyster reef living shoreline approaches therefore failed to optimize the ecological and engineering goals. In both inundation regimes, wave transmission decreased with an increasing freeboard (difference between reef crest elevation and water level), supporting its importance in the wave attenuation capacity of oyster reef living shorelines. However, given that the reef crest elevation (and thus freeboard) should be determined by the inundation duration requirements of oysters, research needs to be re-focused on understanding the implications of other reef parameters (e.g. width) for optimising wave attenuation. A broader understanding of the reef characteristics and seascape contexts that result in effective coastal defense by oyster reefs is needed to inform appropriate design and implementation of oyster-based living shorelines globally. Accepted manuscript version