Evaluating the vulnerability of coralligenous epifauna to macroalgal invasions

1. This work constitutes the first comprehensive study of the epifaunal response to biological invasions in coralligenous habitats, which are one of the main hotspots of biodiversity in the Mediterranean.
2. The epifaunal community inhabiting the invasive macroalga Rugulopteryx okamurae and other dominant sessile hosts on coralligenous habitats (i.e. the sponge Spongia lamella, the gorgonian Paramuricea clavata, and the macroalga Sphaerococcus coronopifolius) was characterized. A total of 137 taxa were found.
3. There was a lack of functional equivalence between macroalgal species (both native and invasive) and sessile invertebrates. Despite the absence of significant differences in mean density values and number of species per replicate among host species, epifaunal composition on gorgonians and sponges differed significantly from that on both macroalgae.
4. Epifaunal assemblages, especially those inhabiting macroalgal species, were dominated by generalist detritivorous species that can inhabit different hosts, while specialized interactions between mobile epifauna and sessile hosts were observed almost exclusively on sessile invertebrates. Moreover, epifaunal community associated with invertebrate hosts showed higher spatial heterogeneity in comparison with native and invasive macroalgae.
5. A competitive displacement of native hosts by the spreading of R. okamurae on coralligenous habitats would likely result in a biotic impoverishment in terms of overall number of species and a taxonomical and functional homogenization of the epifaunal community. Specialist species with a heterogeneous distribution could be gradually replaced by a spatially homogeneous assemblage dominated by generalist species.

     

First attempt of interspecific hybridization between the shrimps Penaeus kerathurus Forskäl,1775 and Penaeus japonicus Bate, 1888

This paper reports preliminary studies designed to evaluate hybridization through natural mating and artificial insemination between female Penaeus japonicus Bate, 1888 and male Penaeus kerathurus Forskäl, 1775. Although both species were able to mature in captivity, natural copulation was not achieved. Different techniques, including manual squeezing in the base of the fifth pair of pereiopods, electrical stimulation and dissection, were used for the artificial insemination experiments. However, only dissection gave spermatophores. Stained sperm showed no malformations and its viability was very high. Seven out of 10 inseminations (70%) produced eggs, but the development of embryos was abnormal. It is suggested that the high genetic distance between these species is responsible for these results.     

Gametogenic cycle and variations in oocyte size of Tapes philippinarum from the Lagoon of Venice

The gametogenic cycle of the clam Tapes philippinarum was studied in two populations from different areas of the Lagoon of Venice: S. Angelo (central basin) and Chioggia (southern basin). Samples were collected at regular intervals from July 2000 to July 2001. The study was performed by microscopic observations of histological sections of gonadic tissue and by measuring follicular and oocyte sizes by image analysis. Gametogenesis began in January and was clearly evident until May. Ripe clams appeared in April, and most active spawning occurred in May, continuing during summer until September. Measurements performed using image analysis (i.e., follicular area, percentage of reproductive tissue, oocyte diameter, percentage of resorbing area) highlighted environmental differences between the two sampling sites, demonstrating the better condition of clams from Chioggia.     

Critical loads of acidity and nitrogen,based on multiple criteria for different swedish ecosystems

The critical loads of acidity and nitrogen has been mapped for Swedish forest soils, using data from the Swedish Forest Inventory. The Swedish critical load map used in negotiations has been based on a number of ecological receptors. For terrestrial ecosystems criteria based on no adverse effect on growth, soil stability and groundwater quality was used. For surface waters, stream and lake biology was used as indicators for setting limits to acidification. A reduction of 75% of the acidity deposition in relation to 1988 is required in order to protect 95% of the forest resource in Sweden from effects of soil acidification. A reduction of 50% of the nitrogen deposition is required to avoid exceedance in more than 5% of the area. The mapping work was carried out by using the PROFILE model.     

Use of heme iron concentrate in the fortification of weaning foods

The purpose of this study was to evaluate the technological feasibility of fortifying homogenized weaning food with a porcine heme concentrate. The stability of iron and the organoleptic qualities of two infant weaning foods (a commercial homogenized nonfortified weaning food, NFWF, and the same food fortified with 0.5% of porcine heme concentrate, FWF) were tested throughout 8 months of storage at room temperature and at 37 degrees C. Heme iron decreased with storage time; however, the proportion of this highly available iron was considerably higher in FWF than in NFWF. The addition of heme iron changed significantly the color of the weaning food measured instrumentally, although high temperatures and length of storage time, did not modify Lab, chroma, and hue angle values in both samples. Organoleptic attributes presented a marked stability even in NFWF stored at room temperature and 37 degrees C.     

Simultaneous HPLC analysis of alpha-tocopherol and cholesterol in fresh pig meat

A method has been developed for simultaneously determining alpha-tocopherol and cholesterol in fresh pig meat by HPLC. It allows a reduction in the number of analyses and brings savings in time and materials. The unsaponifiable fraction is extracted following the modified method of Liu et al. (Liu, Q.; Scheller, K. K.; Schaefer, D. M. Technical note: A simplified procedure for vitamin E determination in beef muscle. J. Anim. Sci. 1996, 74, 2406-2410). The modifications introduced are the use of nitrogen atmosphere during the extraction, the addition of an antioxidant in the organic extraction phase, and the use of alpha-tocopherol itself as an internal standard. There is then a chromatographic analysis which allows the separation of the two compounds in question. To identify and quantify, two different detectors are used in series: the first is a fluorescence detector (alpha-tocopherol), and the second is a light-scattering detector (cholesterol). The technique shows sufficient sensitivity to determine the normal levels of alpha-tocopherol and cholesterol in meat, with recovery percentages of 78% and 97%, respectively. The average amount of alpha-tocopherol and cholesterol in samples from pig Longissimus dorsi muscle analyzed using this method is 1.8 and 620 mg/kg of fresh meat, respectively.     

Influence of agronomic variables on the composition of mate tea leaves (Ilex paraguariensis) extracts obtained from CO2 extraction at 30 degrees C and 175 bar

The aim of this work is to assess the influence of light intensity (plants with direct sun exposure and in a controlled light intensity) and age of leaves (6-24 months) on the characteristics of the extracts of mate tea leaves obtained from carbon dioxide at high pressures. Samples of mate were collected in an experiment conducted under agronomic control at Industria e Comercio de Erva-Mate Bar?o LTDA, Brazil. The content of selected organic compounds of the extracts was evaluated by gas chromatography together with mass spectrometry. Quantitative analysis of caffeine, theobromine, phytol, vitamin E, squalene, and stigmasterol was performed, and the results showed that field variables exert a strong influence on the liquid yield and on the chemical distribution of the extracts.     

Factors influencing acrylamide content and color in rye crisp bread

An industrial baking procedure for yeast-leavened whole-grain rye crisp bread was adapted to local laboratory conditions to study the effect of time and temperature of baking and the addition of fructose, asparagine, and oat-bran concentrate on the acrylamide content and color of the bread. Baking time and temperature affected acrylamide content that increased from 10 to 30 mug/kg of bread at the combination of a long time and high temperature, with a significant interaction between the two factors (p < 0.008). Added asparagine had a significant effect (p < 0.001) on the formation of acrylamide, but fructose did not. There was a correlation between acrylamide content and color of the milled bread in the time-temperature experiment, but this correlation was not observed in the experiment with added precursors. Added oat-bran concentrate with high content of mixed-linkage beta-glucan did not influence the acrylamide content in the breads.     

Diffusible signals, not autonomous mechanisms, determine the main proximodistal limb subdivision

Vertebrate limbs develop three main proximodistal (PD) segments (upper arm, forearm, and hand) in a proximal-to-distal sequence. Despite extensive research into limb development, whether PD specification occurs through nonautonomous or autonomous mechanisms is not resolved. Heterotopic transplantation of intact and recombinant chicken limb buds identifies signals in the embryo trunk that proximalize distal limb cells to generate a complete PD axis. In these transplants, retinoic acid induces proximalization, which is counteracted by fibroblast growth factors from the distal limb bud; these related actions suggest that the first limb-bud PD regionalization results from the balance between proximal and distal signals. The plasticity of limb progenitor cell identity in response to diffusible signals provides a unifying view of PD patterning during vertebrate limb development and regeneration.     

Effect of hop (Humulus lupulus L.) flavonoids on aromatase (estrogen synthase) activity

The aim of this work was to study the effect of the prenylflavonoids xanthohumol, isoxanthohumol, and 8-prenylnaringenin on the activity and expression of the enzyme aromatase (estrogen synthase). The effect of different kinds of beer containing these prenylflavonoids was also tested. Aromatase activity was determined by measuring the release of tritiated water during the conversion of [(3)H]androstenedione to estrone. Aromatase expression was determined by RT-PCR. This assay was carried out in choriocarcinoma-derived JAR cells. The tested prenylflavonoids were able to inhibit estrogen formation, and their IC(50) values were determined, although no effect on aromatase expression was found. Lager beer, alcohol-free beer, stout beer, and xanthohumol-rich stout beer (200 microL/mL) significantly decreased aromatase activity. In conclusion, prenylflavonoids are able to modulate aromatase activity, decreasing estrogen synthesis, with relevance for the prevention and treatment of estrogen-dependent disorders such as breast cancer.