Are Acartia tonsa cold‐stored eggs a suitable food source for the marine ornamental species Amphiprion polymnus? A feeding study

Copepods are the natural food items for marine fish larvae but are still difficult to be cultured on a continuous basis. Therefore, suitable storage techniques for copepod subitaneous eggs are of great interest. Cold‐stored copepod embryos still develop and retain a physiological activity during the cold storage period. As a consequence, their nutritional quality may change over the time of storage with these changes possibly affecting both eggs viability and larval fish survival and development. In this study, the clownfish, Amphiprion polymnus, was used as an experimental model to compare, for the first time, the effects of diets based on enriched rotifers and Artemia (control), Acartia tonsa copepods of a continuous culture and A. tonsa originated from 6 months cold‐stored eggs. The effects of the different diets were tested through morphometric, molecular and biochemical approach. This study demonstrated that after a 6 months cold storage period, the quality of copepods obtained from those eggs was suboptimal for A. polymnus larval rearing. In fact, larvae fed those copepods showed lower growth and survival performances respect to the other experimental groups.     

Switching supramolecular polymeric materials with multiple length scales

It was demonstrated that polymeric supramolecular nanostructures with several length scales allow straightforward tailoring of hierarchical order-disorder and order-order transitions and the concurrent switching of functional properties. Poly(4-vinyl pyridine) (P4VP) was stoichiometrically protonated with methane sulfonic acid (MSA) to form P4VP(MSA)1.0, which was then hydrogen-bonded to pentadecylphenol. Microphase separation, re-entrant closed-loop macrophase separation, and high-temperature macrophase separation were observed. When MSA and pentadecylphenol were complexed to the P4VP block of a microphase-separated diblock copolymer poly[styrene-block-(4-vinyl pyridine)], self-organized structures-in-structures were obtained whose hierarchical phase transitions can be controlled systematically. This microstructural control on two different length scales (in the present case, at 48 and 350 angstroms) was then used to introduce temperature-dependent transitions in electrical conductivity.     

Vegetation and Environment in Afforested Sand Dunes at Newborough, Anglesey

Newborough Forest was planted with pines, chiefly Corsican pine,during the period 1947–65. In 1986, its soils and vegetationwere surveyed and related to the preplanting condition of thedunes, inferred from air photographs. The youngest dunes contained4 per cent calcium carbonate in the top 30cm; the oldest wereacid, with no free calcium carbonate. There was little acidificationof the soil and no extra leaching of calcium carbonate due tothe pines. Vegetation under trees varied according to the ageand pH of the dunes. Young dunes were almost bare except formoss; older dunes had been colonized by ferns and brambles.All plant species of the original open dune system had apparentlysurvived in unplanted slacks or on road verges; some had increased.Many new species had invaded, including woodland mosses, ferns,orchids and two species of Pyrola.     

A method for quantifying changes in the epicuticular wax structure of Norway spruce needles

A method for quantifying changes in the epicuticular wax structure of spruce needles (Pieea abies) has been developed for the scanning electron microscope. This evaluation system, based on a five-point scale, classifies only the epistomatal waxes of current-year needles. Two criteria, the different crystal wax forms and the amount of changed wax as a percentage of the total stomatal area have been used for classification. Statistically significant results (accuracy below ± 10% at 5% error level) were obtained under the following conditions. Mixed needle samples were taken from two adjacent trees per site. These were in a dominant and predominant social position in the stand. The needles were collected from the 7^th whorl of sun crowns exposed to all wind directions. The wax quality was determined by evaluating three stomata per needle. One stoma was investigated at the needle base, one m the middle and the third at the apex of the needle. 24 needles were evaluated per site. SEM-Investigations of needle waxes of 25 Austrian forest sites with no local emission source (background sites) showed, that the mean wax quality ranged from 1.6 to 4.1, according to this classification method. Stepwise multiple regression analyses with site characteristics and element contents of the needles (nutrient elements, heavy metals) confirmed correlations between the wax quality and the manganese- and sulphur-content of the needles and also the average degree of crown defoliation.     

Identification and Quantification of Pathogenic Pythium spp. from Soils in Eastern Washington Using Real-Time Polymerase Chain Reaction

ABSTRACT Traditional methods of quantifying Pythium spp. rely on the use of selective media and dilution plating. However, high variability is inherent in this type of enumeration and counts may not be representative of the pathogenic population of Pythium spp. Variable regions of the internal transcribed spacer of the rDNA were used to design species-specific primers for detection and quantification of nine Pythium spp. from soils in eastern Washington. Primer pairs were designed for Pythium abappressorium, P. attrantheridium, P. heterothallicum, P. irregulare group I, P. irregulare group IV, P. paroecandrum, P. rostratifingens, P. sylvaticum, and P. ultimum and used with real-time polymerase chain reaction. Standard curves were generated for each of the species using SYBR Green I fluorescent dye for detection of amplification. Seventy-seven isolates of Pythium were screened to confirm specificity of each primer set. DNA was extracted from soil and standard curves were generated for P. irregulare group I, P. irregulare group IV, and P. ultimum to correlate populations of each species in the soil with quantities of DNA amplified from the same soil. Examination of raw field soils revealed results similar to those observed in previous studies. This new technique for the quantification of Pythium spp. is rapid and accurate, and will be a useful tool in the future study of these pathogenic Pythium spp.     

Growth performance and gastrointestinal microbial ecology responses of piglets receiving Saccharomyces cerevisiae fermentation products after an oral challenge with Escherichia coli (K88)

The effects of Saccharomyces cerevisiae fermentation products (YFP) on growth performance and gastrointestinal (GIT) microbial ecology in 90 weanling pigs orally challenged with Escherichia coli K88(+) (ETEC) were investigated. The YFP were an original YFP product (XPC) and a water-suspendable yeast fermentation prototype (WSYFP) from a commercial company. Treatments consisted of a negative control (NC, no in-feed or in-water additive), carbadox (AB, 55 mg of carbadox/kg of feed), XPC (in feed, 0.2%), and WSYFP (in water, 0.5, 1, or 2 g/pig per day), and each was allotted to 5 pens (3 pigs/pen). The diets met the 1998 NRC specifications. Pigs were acclimated to treatments for a 7-d period before an ETEC challenge. On d 8, blood was collected from pigs to determine the baseline packed cell volume (PCV) measurement, and pigs were orally challenged with ETEC. At various time points postchallenge, blood samples were taken, performance measures and fecal consistency scores were recorded, and gut digesta and tissue samples were taken to evaluate GIT morphology, microbial ecology, and metabolites. Preplanned contrasts were used for comparison. Pigs receiving YFP had greater ADFI than NC pigs on d 3 (424 vs. 378 g/d; P = 0.01) and d 7 (506 vs. 458 g/d; P = 0.03) postchallenge. This effect of YFP on ADFI was similar to that of AB on d 3, but pigs receiving AB ate more (576 vs. 506 g/d; P = 0.03) at d 7 than pigs receiving YFP. Pigs exhibited reduced (P < 0.001) PCV upon ETEC challenge; however, pigs receiving additives sustained a greater (P < 0.05) PCV at 72 h compared with the NC group. Compared with the NC pigs, pigs receiving YFP showed a smaller (P < 0.05) number of ileal mucosa adherent ETEC and prevalence of the order Enterobacteriales in the ileal digesta, which corresponded to less (5.09 vs. 6.97 mg/dL; P = 0.03) colonic ammonia on d 7 postchallenge. Most of the indices for ileal digesta bacterial richness and diversity were greater (P < 0.01) for YFP pigs compared with NC pigs. However, results also indicated that the influence of YFP on the piglet intestinal microenvironment might differ when given in feed or water during ETEC challenge. In conclusion, pigs receiving YFP showed a better appetite in the presence of ETEC, which, together with the greater ileal digesta bacteria richness and diversity and decreased ETEC adhering to the mucosa and reduced colonic ammonia, indicates a healthier GIT environment.