Deeply divergent DNA barcode lineages within Dynamene edwardsi (Isopoda) from the Northeast Atlantic suggest between four to eight cryptic species

This work is part of the DiverseShores (PTDC/BIA-BIC/114526/2009) research project, funded by (FCT) under the COMPETE programme supported by the European Regional Development Fund. FCT also supported a Ph. D. grant to P.V. (SFRH/BD/86536/2012). Part of this work was funded by FEDER through COMPETE and by national funds through FCT/MEC in the scope of the projects FCOMP-01-0124-FEDER-015429 (ref. FCT: PTDC/MAR/113435/2009) and PEst-OE/BIA/UI4050/2014.info:eu-repo/semantics/publishedVersio

Recent developments in manufacturing multiple emulsions using membrane and micro fluidic devices

Membrane and microfluidic devices are new routes for controllable production of multiple emulsions with uniformly sized drops and accurate control of the internal drop structure. Membrane emulsification involves injecting single emulsion through a porous membrane into continuous phase in a stirred cell or cross-flow membrane module. In this work an alternative method to generate shear at the membrane surface was applied, based on the low frequency oscillation of the membrane at 10-90 Hz in a direction perpendicular to the flow of the injected phase. The advantage of oscillating membrane technique is that the risk of the drop breakage in the continuous phase is minimal, because the shear is generated only at the membrane surface. The oscillation signal was provided by an audio generator which fed a power amplifier driving the electro-mechanical oscillator on which the inlet manifold was mounted. The membrane was a microsieve-type membrane with regular pore spacing formed by Ni electroforming. At the constant maximal shear stress at the membrane surface the mean size of oil globules in W/O/W emulsions decreased with increasing the amplitude of oscillation. The most narrow drop size distribution with a span of 0.36 was obtained at 70 Hz and the peak amplitude of about 0.4 mm. A disadvantage of membrane emulsification is that the internal drop structure cannot be accurately controlled. Microfluidic devices with co-axial glass microcapillaries developed in Weitz Lab have been found convenient for controllable generation of both core-shell drops and multiple emulsion drops with a controlled number of inner drops in the outer drop. In this work core-shell drops with a size between 50 and 150 μm have been produced at the production rate ranging from 1,000 to 10,000 drops/s. The shell thickness was accurately controlled by adjusting the ratio of the middle fluid flow rate to the inner fluid flow rate and the drop size decreased with increasing the outer fluid flow rate

Influence of shape and surface charge on the sedimentation of spheroidal, cubic and rectangular cuboid particles

This study investigated the complex settling behaviour of colloidal particles with varied surface charge and shape factors, of specific relevance to nuclear waste processing. Caesium phosphomolybdate (CPM), zirconium molybdate (ZM) and zirconium citromolybdate (ZMCA) were firstly synthesised, producing spheroidal, cubic and rectangular cuboidal morphologies respectively, and compared to agglomerated titania. While zeta-potential measurements indicated all simulant particles attained low isoelectric points, surface group leaching rendered suspensions very acidic, with CPM around its IEP, and ZM/ZMCA stable and positively charged. In sedimentation tests at various concentrations in water and 2 M HNO₃, CPM and titania were found to settle with extremely high hindered settling exponents, consistent with aggregated structures. Exponents for ZM and ZMCA in water were both also well above values for spherical particles; however, this was assumed to be due to heightened drag effects from relative shape factors, rather than aggregation. ZMCA in particular showed a very high exponent of ~ 11.4, due to the propensity for the rod-like particles to settle in a flat conformation. For ZM in acid, double layer compression from the high electrolyte aggregated the dispersions, correlating to a significant increase in the settling exponent. An extended Stokes relationship was additionally used to understand theoretical limits of shape and aggregation on particle size prediction from hindered settling curves. Importantly, calculated sizes were consistent for the stable ZM and ZMCA in water, despite their non-sphericity and enhanced drag. The relationship failed however with agglomerated suspensions, highlighting its application as a general stability test for sedimenting dispersions

A review of astaciculture: freshwater crayfish farming

The farming of freshwater crayfish (astaciculture) is mainly carried out in the southern states of the USA, and in Australia and Europe. Production levels vary with climate but are in the region of 40 000 to 60 000 tonnes per annum. In addition, at least an equivalent amounts is harvested from the wild, particularly in North America, China, Australia, Kenya, Turkey and Europe. Crayfish farming is usually either of an extensive (ranching) or semi-intensive nature, intensive methods being infrequent, except for the rearing of juveniles for stocking (or restocking of natural waters depleted of crayfish). As crayfish do not have larvae and are polytrophic, they are relatively easy to rear, although fecundity is much lower when compared with other cultured crustaceans. At least 85% of world production is based on the red swamp crayfish, Procambarus clarkii, mainly from Louisiana and other southern USA states, but also from China, Kenya and Spain, where it has been introduced. In Australia, three species are of aquacultural importance, the yabbie, Cherax destructor; the marron, C. tenuimanus; and the red claw, C. quadricarinatus. Some very large production units have been built but none have lived up to their promise. The red claw is thought to have considerable aquacultural potential, but, being a tropical species, needs warm water for good growth. In Europe, the only endemic species cultured to any extent is the noble crayfish, Astacus astacus, mainly as juveniles for restocking. It fetches a higher price than other crayfish. The North American signal crayfish, Pacifastacus leniusculus, has been introduced to most European countries, but farmed production is relatively low. About 98% of crayfish consumed in Europe come from extensive systems or the wild harvest. European crayfish markets were upset by the collapse of the Turkish crayfishery (based on Astacus leptoductylus) due to overfishing and disease in the mid-1980s. The environmental impact of crayfish farming is most noticeable in Europe. Crayfish plague, introduced from North America last century, has devastated populations of the native species in many countries. Its spread has been exasperated by the translocation of foreign crayfish (and probably by fish) for aquacultural purposes. In addition, introduced crayfish frequently escape into the wild and form large populations, often in direct competition with native species. Burrowing and prolific species, such as P. clarkii, can also do considerable environmental damage

Mitochondrial DNA variation in four British populations of the white-clawed crayfish,

If recovery programmes are to be initiated in England and Wales, it is very important to obtain information on how genetic variation is partitioned between the remaining populations for the endangered species Austropotamobius pallipes pallipes. A survey of the mtDNA genome, using 12 restriction enzymes revealed 3 haplotypes in 4 British populations. The study reveals a low level of genetic variation amongst four geographically distant populations. Moreover, the most widespread haplotype found in the British populations is also similar to those found in French populations; one of the rare haplotypes found in one English population is also widespread in French populations. Management of crayfish stocks may be possible at a national level however, a more extended study of mtDNA variation is needed to prove this conclusively

Distribution and species identification in the crustacean isopod genus Dynamene Leach, 1814 along the North East Atlantic-Black Sea axis

Sphaeromatid isopods, such as Dynamene, are common and abundant members of the invertebrate fauna of littoral and shallow sublittoral substrates. Six species of Dynamene occur in the northern hemisphere. Only two species exist outside this range, in Australia. The distribution of the various species in the NE Atlantic-Black Sea axis has been controversial due to the difficulty in the identification of the different species. This has led to inaccurate records of their distribution, ultimately generating uncertain or faulty assessments on the biodiversity of these habitats. An update and a clarification about the distribution of this genus is therefore in order. In this study, we describe the distribution of Dynamene species in the light of new records from the NE Atlantic Ocean and its associated islands, and the Mediterranean, Black and Red Seas, and from re-examination of museum and several authors’ personal collections. Based on these observations, we extend the northern and southern limits of D. bidentata (Adams); the western and southern limits of D. magnitorata Holdich; the northern, eastern and western limits of D. edwardsi (Lucas); and the eastern and western limits of D. bifida Torelli. The range of Dynamene tubicauda Holdich is extended, but is still only known from the eastern Mediterranean. We also clarify the synonymy of D. torelliae Holdich with D. bicolor (Rathke), and the occurrence of D. bicolor in the Black Sea. New distribution maps of the six Dynamene species are presented. Illustrated keys to the adult males and females of the northern hemisphere species are provided

Expression profiling and electrophysiological studies suggest a major role for Orai1 in the store-operated Ca2+ influx pathway of platelets and megakaryocytes

Store-operated Ca2+ influx represents a major route by which cytosolic Ca2+ can be elevated during platelet activation, yet its molecular identity in this cell type remains highly controversial. Using quantitative RT-PCR analysis of candidate receptor-operated cation entry pathways in human platelets, we show a 30-fold higher expression of message for the recently discovered Orai1 store-operated Ca2+ channel, and also the store Ca2+ sensor STIM1, when compared to the non-selective cation channels TRPC1, TRPC6 and TRPM2. Orai1 and STIM1 gene transcripts were also detected at higher levels than TRPC1, TRPC6 and TRPM2 in primary murine megakaryocytes and human megakaryocytic cell lines. In direct electrophysiological recordings from murine megakaryocytes, Ca2+ ionophore-induced store depletion stimulated CRAC currents, which are known to require Orai1, and these overlapped with TRPC6-like currents following P2Y receptor activation. Together with recent transgenic studies, these data provide evidence for STIM1:Orai1 as a primary pathway for agonist-evoked Ca2+ influx in the platelet and megakaryocyte