Movement Patterns of the White-clawed Crayfish, Austropotamobius pallipes, in a Tuscan Stream

Abstract We analyzed spatial behavior in the white-clawed crayfish, Austropotamobius pallipes, inhabiting a stream in Tuscany (Italy). Our study suggests an overall complex movement pattern, where nomadic movements are intercalated by stationary phases. There was a low rate of recapture within the stretch of stream inspected, suggesting either a tendency of the species to disperse or a mortality rate caused by predators or the loss of tags with molts. However, one part of the population showed a conservative use of space, as indicated by 1) more extensive movement during a 24-h cycle than during the one-year cycle, 2) a weak tendency to return to the "home" pool if released at a distance of 50 m, and 3) an equal distribution of up- and downstream movements. No correlation was found between either 1) the displacement from the point of first capture and the length of time the specimen was followed through recaptures or 2) the number of captures and the maximum distance traveled

FEEDING PREFERENCES OF THE INVASIVE CRAYFISH, PROCAMBARUS CLARKII

This laboratory study analyzes feeding preferences of a crayfish species with high invasive potentials, the red swamp crayfish Procambarus clarkii. We first conducted a series of multiple-choice tests among fresh plants (3 tests, one per each of three seasons, i.e. spring, summer, and autumn) and animals (1 test in summer). In the first tests, crayfish were simultaneously offered fresh pieces of seven plants of different growth forms and taxonomic groups, selected on the basis of their availability in the habitat. In the second test, the offered animals were dead earthworms, rainbow trout fry, and toad tadpoles. Then, a binary choice test was run in autumn between the most preferred plant (Urtica sp.) and earthworms. The percentages of organic C and N contents were measured for each food category using a gas-chromatography technique and the assimilation efficiency of both dry mass and organic content was assessed in a dedicated experiment. The results showed that P. clarkii is selective when offered fresh plants, consuming a relatively larger biomass of Urtica (in the three seasons examined), green algae (in spring), and Polygonum (in summer and autumn). Surprisingly, crayfish did not exhibit preference for any animal prey. Also, P. clarkii’s feeding decisions seemed not to be associated with either the availability of plants in the habitat or their occurrence in the gut contents of wild crayfish. Neither did their ingested biomass depend on the organic content or assimilation efficiency. Procambarus clarkii preferred Urtica sp. over earthworms, notwithstanding the higher nutritional value and assimilation efficiency of the latter. The above results might suggest that feeding preferences of the species often depend on factors other than nutritional value and digestibility. Future studies will analyze all the possible factors together in order to unravel the rules that govern feeding preferences in crayfish. In the case of invasive species, such knowledge will highly contribute to planning science-based actions for their containment and mitigation

Linguistica del testo e analisi del discorso

L'articolo offre una rassegna aggiornata degli studi più rilevanti sulla linguistica testuale e sull'analisi del discorso, con particolare attenzione a questioni terminologiche, alla nascita della disciplina, al suo sviluppo, alle tematiche attuali e agli sviluppi futuri

Environmental correlates of two macro-decapods distribution in Central Italy: Multi-dimensional ecological knowledge as a tool for conservation of endangered species

Using a multi-dimensional ecological design, this study aimed first to analyse whether local environmental conditions can account for the spatial segregation of two Italian native decapods, the crayfish Austropotamobius italicus and the river crab Potamon fluviatile, in Central Italy freshwater ecosystems. Second, we aimed to analyse which environmental variables were more closely associated with the presence/absence of the two decapods in specific sites within their distribution area. Following a factorial design, a total of 32 sites were selected in two neighbouring geographic areas, one occupied by crayfish and one by crabs. Within each distribution area, eight streams where the decapod was present and eight where it was not present were selected. At each site, macro-invertebrate community composition and 16 abiotic variables were recorded and analysed with multi-variate methods. Variations in physical (minimum and maximum temperatures), chemical (calcium, oxygen, nitrate and nitrite) and geomorphological (substrate composition) parameters explained spatial segregation of P. fluviatile and A. italicus in the study area. The occurrence of crayfish reflected variations of chemistry (such as pH, calcium, nitrate and nitrite concentrations), temperature, water depth and substrate composition. On the contrary, the presence of the river crab, within its occurrence zone, was not associated to any biotic and abiotic parameters and was probably affected by anthropogenic pressure and uncontrolled harvesting. These findings provide fundamental ecological data for the maintenance of the two decapod natural populations as well as for the selection of areas and streams adequate for their reintroduction. © 2007 Elsevier Ltd. All rights reserved.Link_to_subscribed_fulltex

Bilosomes as Nanocarriers for the Drug and Vaccine Delivery against Gastrointestinal Infections: Opportunities and Challenges

The gastrointestinal tract (GIT) environment has an intricate and complex nature, limiting drugs’ stability, oral bioavailability, and adsorption. Additionally, due to the drugs’ toxicity and side effects, renders are continuously seeking novel delivery systems. Lipid-based drug delivery vesicles have shown various loading capacities and high stability levels within the GIT. Indeed, most vesicular platforms fail to efficiently deliver drugs toward this route. Notably, the stability of vesicular constructs is different based on the different ingredients added. A low GIT stability of liposomes and niosomes and a low loading capacity of exosomes in drug delivery have been described in the literature. Bilosomes are nonionic, amphiphilic, flexible surfactant vehicles that contain bile salts for the improvement of drug and vaccine delivery. The bilosomes’ stability and plasticity in the GIT facilitate the efficient carriage of drugs (such as antimicrobial, antiparasitic, and antifungal drugs), vaccines, and bioactive compounds to treat infectious agents. Considering the intricate and harsh nature of the GIT, bilosomal formulations of oral substances have a remarkably enhanced delivery efficiency, overcoming these conditions. This review aimed to evaluate the potential of bilosomes as drug delivery platforms for antimicrobial, antiviral, antifungal, and antiparasitic GIT-associated drugs and vaccines

Inhibiting beta-alanine transamination : a way to promote muscle histidine-containing dipeptide loading in mice?

Purpose. Of the orally supplied beta-alanine (BA), only 2-3% is excreted in the urine and only 1-6% is converted to muscle carnosine during a long-term supplementation protocol1. Moreover, it was already shown in the ‘50s that more than 90% of the injected C14-labeled BA in rats was recovered in the expired CO2 in 5 hours². We now hypothesize that BA can be transaminated into malonate semi-aldehyde by the enzymes ‘beta-alanine - 2-oxoglutarate transaminase’ (ABAT) and ‘beta-alanine-pyruvate transaminase’ (AGXT2). Vigabatrin (VG) is a specific inhibitor of ABAT, while aminooxyacetic acid (AOA) inhibits all pyridoxal-5’-phosphate (PLP) - dependent enzymes, including ABAT and AGXT2. The aim of the present study was to elucidate the effect of specific (VG) and non-specific (AOA) BA transaminase inhibitors on BA-induced muscle HCD loading in mice. Methods. A total of 66 male C57BL/6 mice (10 weeks old) were used in this study. Mice were randomly divided in 6 groups and underwent different treatments, which differed in the amount of BA in the drinking water (0%, 0.1%, 0.6%, 1.2%) and in the subcutaneous injection of VG, AOA or saline (every 72h or 24h). After 2 weeks, muscles and organs were dissected and blood was collected. Serum BA levels were analysed by means of HPLC. Brain ABAT activity was determined by the fluorometric quantification of NADH formation following addition of GABA to a brain homogenate. Muscle and organ HCD levels were analysed by means of LC-MS/MS and qPCR analysis was used to measure the expression of carnosine-related enzymes and transporters. Results. Taurine transporter and carnosine synthesis enzyme are mainly expressed in muscles and brain. In contrast, the BA transaminating enzymes show highest expression in liver and kidney and very low expression in muscles. Brain ABAT activity is significantly decreased when VG or AOA is administered (-82.2% and -87.8%, respectively; p < 0.001). Serum BA levels are not affected by the supplementation of 0.1% BA alone or in combination with VG administration, but significant increases are found when this low amount of BA is combined with AOA (p = 0.007 vs 0.1%BA – SAL for serum). Subsequently, this leads to significantly higher HCD loading in the different muscles and highest effects are found in soleus and heart (p < 0.001 for 0.1%BA – AOA vs 0.1%BA – SAL). The more glycolytic muscles also show higher HCD loading with AOA administration (p < 0.001 and p = 0.024 vs 0%BA – SAL for tibialis anterior and gastrocnemius, respectively), but effects are absent in kidney and brain. Furthermore, no effects of specific inhibition (VG) were found in any of these tissues. Conclusion. Non-specific inhibition of BA transamination has positive effects on BA-induced HCD loading in both muscles and organs, suggesting that muscle HCD synthesis is dependent on the amount of beta-alanine transamination in mice. References: [1] Stegen S., Blancquaert L., Everaert I., et al. Med Sci Sports Exc. 2013, 45 (8): 1478-85. [2] Pihl and Fritzson. J Biol Chem. 1955, 215: 345-51

Unraveling the Gut Microbiome–Diet Connection: Exploring the Impact of Digital Precision and Personalized Nutrition on Microbiota Composition and Host Physiology

The human gut microbiome, an intricate ecosystem housing trillions of microorganisms within the gastrointestinal tract, holds significant importance in human health and the development of diseases. Recent advances in technology have allowed for an in-depth exploration of the gut microbiome, shedding light on its composition and functions. Of particular interest is the role of diet in shaping the gut microbiome, influencing its diversity, population size, and metabolic functions. Precision nutrition, a personalized approach based on individual characteristics, has shown promise in directly impacting the composition of the gut microbiome. However, to fully understand the long-term effects of specific diets and food components on the gut microbiome and to identify the variations between individuals, longitudinal studies are crucial. Additionally, precise methods for collecting dietary data, alongside the application of machine learning techniques, hold immense potential in comprehending the gut microbiome’s response to diet and providing tailored lifestyle recommendations. In this study, we investigated the complex mechanisms that govern the diverse impacts of nutrients and specific foods on the equilibrium and functioning of the individual gut microbiome of seven volunteers (four females and three males) with an average age of 40.9 ± 10.3 years, aiming at identifying potential therapeutic targets, thus making valuable contributions to the field of personalized nutrition. These findings have the potential to revolutionize the development of highly effective strategies that are tailored to individual requirements for the management and treatment of various diseases