1,501 research outputs found
Sopravvivenza di Listeria monocytogenes in campioni di salmone affumicato artificialmente contaminati
No full textTra i vari alimenti segnalati quali potenziali sorgenti di listeriosi sta aumentando l'importanza di quelli di origine ittica. Nell'ambito di uno studio sulle infezioni a trasmissione alimentare, ci e' sembrato interessante valutare la sopravvivenza e la velocita' di moltiplicazione di L. monocytogenes, contaminando artificialmente confezioni di salmone affumicato. I risultati preliminari ottenuti sembrano confermare anche in questo alimento la capacita' di sopravvivenza e di moltiplicazione in ambiente refrigerato, con un aumento di 1 log gia' a partire dalla seconda settimana, mentre i valori piu' elevati si sono registrati dalla terza e quarta settimana (2 log). In nessun caso si e' avuta l'inattivazione dei microrganismo, ne' una drastica riduzione riconducibile alla concorrenza vitale di microrganismi deterioranti eventualmente present
The anterior pituitary gland as a possible site of action of kainic acid
No full textThe purpose of the present study was to analyze the direct effect of kainic acid (KA), an agonist of L-Glutamate, on the secretion of LH and FSH from anterior pituitary (AP) of male rats perifused in vitro. At low concentrations (1 microM), KA was able to stimulate the release of both gonadotropins from AP of 50-day-old male rats, but the response to subsequent stimuli was markedly impaired. This, however, was not due to a neurotoxic action of KA, but seemed rather suggestive of a down-regulation or desensitization of KA receptors. The stimulatory action of KA on LH and FSH secretion was age-dependent, since the agonist was completely ineffective on the AP of 75-day- and 18-month-old male rats. DNQX (6,7-dinitroquinoxaline-2,3-dione), a specific antagonist of the KA receptor subtype, was able to block the KA-induced gonadotropin secretion; similarly, AP-5 (2-amino-5-phosphonovalerate), a competitive NMDA receptor antagonist, prevented the stimulatory effect of KA on LH and FSH release. An interaction between the opiatergic and the excitatory aminoacid (EAA) systems emerged from the observation that pulses of KA applied to AP of 50-day-old male rats during a continuous perifusion with a medium containing morphine (5 microM) failed to increase gonadotropin secretion. These results indicate that KA can, at low concentrations, directly stimulate LH and FSH secretion by acting at AP level; this effect disappears with progression of age, and might be exerted both through NMDA and non-NMDA receptor subtypes. Finally, the results provide evidence that opioids and excitatory aminoacids might influence gonadotropin secretion from AP by acting in opposite directions
Biological characteristics of LABLYS98, a Lactobacillus sporogenes for use as probiotic compound
No full textLactobacillus sporogenes (Bacillus coagulans), a spore-forming lactobacillus chosen as biological agent in a formulation for probiotic use, was cultured in media added with L-lysine monohydrochloride to increase the metabolic potentiality. The resulting strain LABLYS98 is stored at the German Collection of Microorganisms and labelled as DSM 12316. Further studies, carried out on the biological characteristics of LABLYS98, showed high stability, acid resistance, production of a large amount of lactic acid (L+) if compared with the original strain (L. sporogenes), moderate adherence to HEp-2 cells and antibacterial activity against many microorganisms used as indicators (L. monocytogenes, Enterococcus spp., A. hydrophila, etc.
Efficacy and Synergistic Potential of Cinnamon (Cinnamomum zeylanicum) and Clove (Syzygium aromaticum L. Merr. & Perry) Essential Oils to Control Food-Borne Pathogens in Fresh-Cut Fruits
No full textThe presence of microbial pathogens in ready-to-eat produce represents a serious health problem. The antibacterial activity of cinnamon (Cinnamomum zeylanicum) and clove (Syzygium aromaticum L. Merr. & Perry) essential oils (EOs) was determined toward food-borne pathogens by agar disk diffusion and minimum inhibitory concentration (MIC) assays. The growth kinetics of all strains, both in a buffer suspension assay and “on food” in artificially contaminated samples, were also investigated. The two EOs demonstrated a good antibacterial effect both alone and in combination (EO/EO). The use of EO/EO led to a synergistic antibacterial effect, also confirmed by the growth kinetics studies, where the EOs were active after 10 h of incubation (p < 0.0001) at significantly lower concentrations than those when alone. In the “on food” studies performed on artificially contaminated fruit samples stored at 4 °C for 8 days, the greatest killing activity was observed at the end of the trial (8 days) with a reduction of up to 7 log CFU/g compared to the control. These results confirm the good antibacterial activity of the EOs, which were more effective when used in combination. Data from the "on food" studies suggest cinnamon and clove essential oils, traditionally used in the food industry, as a possible natural alternative to chemical additives.
Keywords: cinnamon and clove essential oils; synergistic activity; food-borne pathogens; fresh-cut fruit; bio-preservatio
Sensibilità ai biocidi di biofilm formati in vitro da Legionella pneumophila ed altri batteri acquatici
No full textIl biofilm è un micro-sistema acquatico che fornisce ai microrganismi una notevole protezione nei confronti dei biocidi e rappresenta una importante nicchia ecologica in cui i batteri acquatici, tra cui L. pneumophila, possono sopravvivere e proliferare. Al fine di poter controllare la presenza e la diffusione di Legionella pneumophila ed altri batteri potenzialmente patogeni ad habitat idrico, appare di fondamentale importanza la conoscenza del ruolo protettivo del biofilm nei confronti di sostanze potenzialmente utilizzabili nella pratica di disinfezione.Nel presente studio è stata testata l’efficacia di alcuni biocidi (clorexidina e bronopol) e ioni metallici (rame e argento) su biofilm formati in vitro da ceppi batterici di derivazione idrica che avevano mostrato una spiccata attitudine ad aderire alle superfici per formare biofilm maturi.È stata valutata la capacità di tali sostanze, addizionate a diverse concentrazioni, di interferire con la formazione del biofilm prodotto in acqua condottata sintetica da sospensioni batteriche. I risultati hanno mostrato che la formazione del biofilm ottenuto da Pseudomonas aeruginosa e Pseudomonas fluorescens non è risultata inibita dai biocidi alle massime concentrazioni testate (250mg/l); leggermente più sensibile è risultato quello prodotto da Legionella pneumophila e Burkholderia cepacia. Al contrario le sospensioni da cui i biofilm si sono originati sono risultate estremamente sensibili alle sostanze in esame, essendo completamente abbattute alle concentrazioni minime testate (10-50mg/l).Parallelamente sono state studiate le potenzialità biocide delle stesse sostanze sui biofilm preformati (7giorni). Questi si sono mostrati insensibili al trattamento con concentrazioni superiori (fino a 1250 mg/l). Il bronopol ha evidenziato le più limitate potenzialità antibatteriche, l’argento ha mostrato una discreta attività, mentre la clorexidina è risultata il biocida più efficace. Queste considerazioni giustificano le notevoli difficoltà che si incontrano nell’eradicare Legionella pneumophila ed altri batteri di interesse per la salute umana dai serbatoi di infezione e rafforzano la necessità di ulteriori approfondimenti
Quelques aspects de la biologie de Diclidophlebia xuani Messi et al. (Hemiptera : Psyllidae), ravageur de Ricinodendron heudelotii Baill. (Euphorbiaceae) au Cameoun
No full textIntroduction. Ricinodendron heudelotii Baill. est une essence forestière en voie de domestication au Cameroun où la plante est appréciée pour ses vertus alimentaires, écologiques et médicinales. Les dégâts causés par le psylle Diclidophlebia xuani Messi et al. aux jeunes plants, en pépinière ou après leur plantation, constituent l\u27une des principales contraintes à la domestication de l\u27espèce. La biologie de ce ravageur a donc été étudiée afin d\u27envisager son contrôle. Matériel et méthodes. Différents aspects de la biologie de D. xuani ont été abordés: processus d\u27accouplement, choix du site de ponte par la femelle, maturation sexuelle des imagos, fécondité des femelles, longévité des imagos, développement embryonnaire et larvaire, sex-ratio à l\u27émergence et spécificité alimentaire. Les expérimentations ont eu lieu dans la région de Yaoundé soit en champ, soit en milieu contrôlé durant les années 2001 et 2002. Résultats et discussion. Les mâles de D. xuani ont émergé avant les femelles et le rapprochement des sexes a eu lieu 15 min environ après la mue imaginale. La longévité des femelles a été de 29 jours en moyenne, celle des mâles, de 7 jours. La ponte a commencé 3 jours après l\u27émergence et s\u27est poursuivie jusqu\u27à la fin de la vie de la femelle. En période chaude (28°C environ), une femelle a pondu en moyenne 532 oeufs pendant toute sa vie; en période de basses températures (24°C à 26°C environ), la fécondité moyenne a été de 758 oeufs. Les oeufs sont essentiellement déposés sur les étages foliaires les plus jeunes de R. heudelotii. Les développements embryonnaire et larvaire ont duré respectivement 7 jours et 22 jours environ. Le cycle de développement, d\u27oeuf à oeuf, a nécessité 32 jours en moyenne. Le sex-ratio a été proche de 1. Conclusion. D. xuani se développe entièrement et sans interruption sur R. heudelotii; il n\u27a jamais été rencontré sur d\u27autres espèces de plantes. Il serait donc étroitement associé à cette plante
New Tunneled Buccal Fat Pad Flap for Palatal Reconstruction
No full textIn the palatal defects due to surgical resection, flap selection is very important for a correct reconstruction. Different methods have been suggested over the time, however the pedicled buccal fat pad is a simple, effective, reliable flap for reconstruction after palate tumor resection. The aim of the present study is to introduce a new surgical technique for palate reconstruction with pedicled buccal fat pad flap exposing the advantages. The Authors performed this procedure in 17 patients in order to treat medium-sized oncologic surgical defect of palate region in the period between 2016 and 2019. Complete wound healing after only 4 weeks without complication after 12 months follow-up was observed. This is the first cases series described with this new technique
Performance of low-resistivity single and dual-gap RPCs for LHCb
No full textResistive plate chambers (RPC) are strong candidates for the outer regions of the LHCb muon detector. We have tested single-gap and dual-gap detectors built with low-resistivity phenolic plates ( rho =9*10/sup 9/ Omega cm) and operated in avalanche mode. Measurements have been performed over a wide range of beam intensities and on the GIF at CERN. The results are presented and discussed, with special emphasis on the detection efficiency. (6 refs)
Controllo e significato della contaminazione microbica ambientale in un impianto di trasformazione alimentare
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