Caratterizzazione fenotipica e genotipica di microrganismi psicrotrofi isolati da panne affiorate di latte

Il Trentingrana rientra in quella categoria di formaggi a latte crudo caratterizzati da lunghi tempi di stagionatura e maturazione, dell’ordine di alcuni mesi fino a più anni. La natura di questi tipi di formaggi e il loro invecchiamento, potendo favorire nel tempo la comparsa di difetti di origine microbica, richiede per la produzione latte di una certa qualità, ottenuto in idonee condizioni igieniche e trasportato in caseificio in modo rapido ed efficiente. Poiché il Trentingrana è prodotto con latte parzialmente scremato, dopo affioramento notturno della sua parte grassa, il controllo della temperatura del latte alla stalla, durante il conferimento e la sosta al caseificio, diventa cruciale per il contenimento dello sviluppo della microflora mesofila-lattica, che altrimenti potrebbe compromettere l’attitudine alla caseificazione del latte stesso. Tuttavia la refrigerazione del latte, parallelamente ad un ritardo o inibizione dello sviluppo della carica mesofila, può conferire un vantaggio selettivo alle specie di microrganismi psicrotrofi potenzialmente residenti nel latte. L’affioramento dei globuli di grasso, oltre a consentire una parziale scrematura, permette di fatto una debatterizzazione, concentrando nelle panne le cellule batteriche, sia quelle mesofile che le psicrotrofe. Sebbene esistano in letteratura alcuni studi sulla microflora psicrotrofa residente nel latte crudo, ad oggi nessun lavoro è stato pubblicato sullo studio delle popolazioni microbiche di panne d’affioramento, con particolare attenzione alle specie psicrotrofe e alle possibili ricadute delle loro attività enzimatiche sul prodotto finito (formaggio). Oggetto del presente lavoro è pertanto lo studio della microflora psicrotrofa di 78 campioni di panne ottenute per affioramento da latte crudo destinato alla produzione del formaggio Trentingrana. Per ogni campione sono stati contati e isolati i batteri psicrotrofi, per un totale di 190 isolamenti. Tutti gli isolati sono stati descritti al microscopio e classificati come Gram positivi o Gram negativi quindi sono stati caratterizzati fenotipicamente e identificati genotipicamente. Per la caratterizzazione fenotipica si è testata - la crescita a 10°C, 15°C, 20°C, 30°C e 37°C; - la produzione di catalasi, ossidasi, lipasi, lecitinasi ed esoproteasi caseiniche; - la crescita su terreno Pseudomonas medium; - la crescita su terreno VRBA; - la crescita alle concentrazioni di 5µg/ml, 10µg/ml, 15µg/ml, 20µg/ml dei seguenti antibiotici: eritromicina, tetraciclina, vancomicina, kanamicina, cefalosporina, cloramfenicolo. Sulla base dei risultati delle prove fenotipiche si è potuta attestare un’ampia biodiversità nella microflora psicrotrofa delle panne in esame: sono stati individuati 30 specie appartenenti al genere Pseudomonas, 7 batteri lattici, 6 Enterobatteriaceae e altri batteri psicrotrofi, che sono stati riuniti in un quarto gruppo. Di tutti gli isolati, 21, 10 dei quali appartenenti al genere Pseudomonas, hanno mostrato attività esoproteasica alle basse temperature, 108, 12 dei quali proteolitici, hanno mostrato attività lipolitica, per un totale di 117 ceppi con attività potenzialmente dannosa ai fini della produzione casearia. Alla caratterizzazione fenotipica è seguita l’identificazione genotipica. I ceppi presunti Pseudomonas sono stati sottoposti a multiplex PCR per valutarne l’appartenenza alle specie P. fragi, P. putida e P. lundensis. Infine tra ognuno dei quattro gruppi identificati a seguito delle prove fenotipiche e tra ogni campione di panna originario, sono stati selezionati i ceppi lipolitici e gli esoproteasici alle basse temperature, per un totale di circa 50 isolati. Questi sono stati identificati tramite sequenziamento di un frammento all’interno del 16S rDNA

Dehydrohalogenation of halobenzenes and C(sp3)-X (X = F, OPh) bond activation by a molecular calcium hydride

International audienceThe molecular calcium hydride, [(BDI)CaF](2) (BDI = HC{(Me)CN-2,6-i-Pr2C6H3}(2)), effects the slow hydrodehalogenation of C6H5X (X = I, Br) to provide benzene and the respective dimeric calcium halides, [(BDI)CaX](2). Although a similar reaction with fluorobenzene was non-discriminating, the analogous hydrogenation of chlorobenzene was observed, albeit this process yields the calcium hydride-chloride as the alkaline earth-containing product. Assessment of the bromide- and chloride-based processes by density functional theory (DFT) calculations, imply that the reactions take place with the retention of the dimeric calcium structures throughout. Both systems invoke an S N Ar-type displacement of the halide, via barriers (in the range 32-34 kcal mol(-1) for C6H5Br and 31.1-32.9 kcal mol(-1) for C6H5Cl), which vary only marginally during the transformation of the initial hydride and halide-hydride intermediates. The isolation of the calcium hydride-chloride is ascribed, therefore, to its more rapid crystallisation and depletion from solution. Also reported is the reactivity of [(BDI)CaH](2) with alpha,alpha,alpha-trifluorotoluene and anisole, which yield the corresponding dicalcium hydride-fluoride and phenoxide derivatives, respectively, rather than the products of directed ortho metalation. (C) 2021 Elsevier Ltd. All rights reserved

Concerning the reactivity of dioxiranes. Observations fromexperiments and theory

The challenging hypothesis of a “biphilic” (i.e., electrophilic vs nucleophilic) character for dioxirane reactivity, which envisages that electron-poor alkenes are attacked by dioxiranes in a nucleophilic fashion, could not be sustained experimentally. Rate data, which estimate Hammett “rho” values for the epoxidation of 3- or 4-substituted cinnamonitriles XâPhsCHdCHsCN, unequivocally allow one to establish that dioxiranes epoxidize electrophilically even alkenes carrying electron-withdrawing groups. The greater propensity of methyl(trifluoromethyl)dioxirane TFDO (1b) to act as an electrophilic oxidant with respect to dimethyldioxirane DDO (1a) parallels the cathode reduction potentials for the two dioxiranes, as measured by cyclic voltammetry. A simple FMO approach for alkene epoxidation is helpful to conceive a likely rationale for the greater oxidizing power of TFDO as compared to DDO

Relative influence of environmental factors on biodiversity and behavioural traits of a rare mesopelagic fish, Trachipterus trachypterus (gmelin, 1789), in a continental shelf front of the Mediterranean Sea

Coastal environments can be influenced by water body masses with particular physical, chemical, and biological properties that create favourable conditions for the development of unique planktonic communities. In this study, we investigated a continental shelf front at Ponza Island (Tyrrhenian Sea) and discussed its diversity and complexity in relation to major environmental parameters. Moon phase and current direction were found to play a significant role in shaping species abundance and behaviour. During in situ observations, we also provided the first data on the behaviour of juveniles of a rare mesopelagic species, Trachipterus trachypterus, suggesting the occurrence of Batesian mimicry

On chip interconnects for multiprocessor turbo decoding architectures

International audienc

Recurrent Endometrial Cancer: Which Is the Best Treatment? Systematic Review of the Literature

Background: Endometrial cancer is the most common gynaecological tumour in developed countries. The overall rate of relapse has remained unchanged in recent decades. Recurrences occur in approximately 20% of endometrioid and 50% of non-endometrioid cases. The aim of this systematic review is to compare different therapeutic strategies in the treatment of endometrial cancer recurrence to evaluate their prognostic and curative effects based on site and type of recurrence. Methods: This systematic review of literature was conducted in accordance with the PRISMA guidelines. The study protocol was registered on PROSPERO (CRD42020154042). PubMed, Embase, Chocrane and Cinahl databases were searched from January 1995 to September 2021. Five retrospective studies were selected. Results: A total of 3571 studies were included in the initial search. Applying the screening criteria, 299 articles were considered eligible for full-text reading, of which, after applying the exclusion criteria, 4 studies were selected for the final analysis and included in the systematic review. No studies were included for a quantitative analysis. We divided the results according to the location of the recurrence: locoregional recurrence, abdominal recurrence and extra abdominal recurrence. Conclusion: the treatment of choice should be assessed according to the relapse location and to the presence of single or multiple lesions. A crucial role in the decision-making algorithm is also the type of adjuvant treatment received at the time of the first diagnosis

Organocalcium-mediated nucleophilic alkylation of benzene

bibtex: ISI:000416584000037 bibtex\location:'1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA',publisher:'AMER ASSOC ADVANCEMENT SCIENCE',type:'Article',affiliation:'Hill, MS (Reprint Author), Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England. Maron, L (Reprint Author), Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Maron, L (Reprint Author), Univ Toulouse III Paul Sabatier, CNRS, Inst Natl Sci Appl, UMR 5215,LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France. Wilson, Andrew S. S.; Hill, Michael S.; Mahon, Mary F., Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England. Dinoi, Chiara; Maron, Laurent, Univ Toulouse, 135 Ave Rangueil, F-31077 Toulouse, France. Dinoi, Chiara; Maron, Laurent, Univ Toulouse III Paul Sabatier, CNRS, Inst Natl Sci Appl, UMR 5215,LPCNO, 135 Ave Rangueil, F-31077 Toulouse, France.','author-email':'[email protected] [email protected]',da:'2018-12-05','doc-delivery-number':'FO2DN',eissn:'1095-9203','funding-acknowledgement':'University of Bath; Engineering and Physical Sciences Research Council','funding-text':'We thank the University of Bath and the Engineering and Physical Sciences Research Council for funding of a Doctoral Training Partnership Ph.D. studentship (A.S.S.W.). The crystallographic data for compounds 6, 7, 8, 9, and 6-d have been deposited with the Cambridge Crystallographic Data Centre as entries 1565865 to 1565869, respectively. All other experimental data are presented in the supplementary materials. Data file S1 contains the Cartesian coordinates for the calculated structures described in this study. Data file S2 contains the Cartesian coordinates of the transition state for the alternative sigma-bond metathesis pathway that was located +29.7 kcal mol\textlessSUP\textgreater-1\textless/SUP\textgreater higher in energy than the metathesis transition state (TSHI) illustrated in Fig. 5.','journal-iso':'Science','keywords-plus':'SOLUBLE CALCIUM HYDRIDE; HEAVY GRIGNARD-REAGENTS; ALKALINE-EARTH METAL; STYRENE POLYMERIZATION; CHEMICAL BEHAVIOR; COMPLEXES; SUBSTITUTION; HYDROGEN; CATALYSIS; STRONTIUM','number-of-cited-references':'40','orcid-numbers':'Wilson, Andrew/0000-0003-3972-9571 Hill, Michael/0000-0001-9784-9649','research-areas':'Science & Technology - Other Topics','times-cited':'15','unique-id':'ISI:000416584000037','usage-count-last-180-days':'27','usage-count-since-2013':'88','web-of-science-categories':'Multidisciplinary Sciences'\The electrophilic aromatic substitution of a C-H bond of benzene is one of the archetypal transformations of organic chemistry. In contrast, the electron-rich p-system of benzene is highly resistant to reactions with electron-rich and negatively charged organic nucleophiles. Here, we report that this previously insurmountable electronic repulsion may be overcome through the use of sufficiently potent organocalcium nucleophiles. Calcium n-alkyl derivatives-synthesized by reaction of ethene, but-1-ene, and hex-1-ene with a dimeric calcium hydride-react with protio and deutero benzene at 60 degrees C through nucleophilic substitution of an aromatic C-D/H bond. These reactions produce the n-alkyl benzenes with regeneration of the calcium hydride. Density functional theory calculations implicate an unstabilized Meisenheimer complex in the C-H activation transition state

Oxidative potential, cytotoxicity, and intracellular oxidative stress generating capacity of PM10: a case study in South of Italy

Long and short-term exposure to atmospheric particulate matter (PM) has detrimental effects on human health. The effective mechanisms leading to PM toxicity are still not fully understood, even if it is known that physical-chemical properties, strongly influenced by sources and atmospheric processes, are known to play an important role. In this work, PM10 samples were collected, at an urban background site in southern Italy, to determine cytotoxicity (using MTT test on A549 cells), genotoxicity (using the comet assay), and intracellular oxidative stress on A549 cells exposed for 24h to aqueous extracts of PM10 samples. Organic carbon (OC) and elemental carbon (EC) content of PM10 and acellular determination of oxidative potential with DTT assay was performed with the objective to compare results of acellular and cellular biological assays. Cellular (OSGCV and MTTV) and acellular (OPDTTV) outcomes, normalised in volume, are well correlated (statistical significant results) with carbon content suggesting that combustion sources play an important role in deter-mining cellular oxidative stress and cytotoxicity of PM10. Even if the number of data is limited, genotoxicity results are well correlated (Pearsons > 0.95) with OSGCV and MTTV and a weaker, but statistically significant correlation was observed with OPDTTV. OSGCV is well correlated with the cell mortality observed with MTTV test and a lower, but still statistical significant correlation is observed between MTTV and OPDDTV. A statistically significant correlation was found between OPDTTV and OSGCV results. When the outcomes of cellular and acellular assay are compared normalised in mass (i.e. intrinsic values), the correlations become significantly weaker suggesting that the different sources acting on the site produces particulate matter with different toxicological potential influ-encing differently the biological tests studie

SARS-CoV-2 concentrations and virus-laden aerosol size distributions in outdoor air in north and south of Italy

The COVID-19 disease spread at different rates in the different countries and in different regions of the same country, as happened in Italy. Transmission by contact or at close range due to large respiratory droplets is widely accepted, however, the role of airborne transmission due to small respiratory droplets emitted by infected individuals (also asymptomatic) is controversial. It was suggested that outdoor airborne transmission could play a role in determining the differences observed in the spread rate. Concentrations of virus-laden aerosol are still poorly known and contrasting results are reported, especially for outdoor environments. Here we investigated outdoor concentrations and size distributions of virus-laden aerosol simultaneously collected during the pandemic, in May 2020, in northern (Veneto) and southern (Apulia) regions of Italy. The two regions exhibited significantly different prevalence of COVID-19. Genetic material of SARS-CoV-2 (RNA) was determined, using both real time RT-PCR and ddPCR, in air samples collected using PM10 samplers and cascade impactors able to separate 12 size ranges from nanoparticles (diameter D < 0.056 µm) up to coarse particles (D > 18 µm). Air samples tested negative for the presence of SARS-CoV-2 at both sites, viral particles concentrations were <0.8 copies m−3 in PM10 and <0.4 copies m−3 in each size range investigated. Outdoor air in residential and urban areas was generally not infectious and safe for the public in both northern and southern Italy, with the possible exclusion of very crowded sites. Therefore, it is likely that outdoor airborne transmission does not explain the difference in the spread of COVID-19 observed in the two Italian regions

Magnesium hydride alkene insertion and catalytic hydrosilylation

International audienceThe dimeric beta-diketiminato magnesium hydride, [(BDI)MgH](2), reacts at 80 degrees C with the terminal alkenes, 1-hexene, 1-octene, 3-phenyl-1-propene and 3,3-dimethyl-butene to provide the respective n-hexyl, n-octyl, 3-phenylpropyl and 3,3-dimethyl-butyl magnesium organometallics. The facility for and the regiodiscrimination of these reactions are profoundly affected by the steric demands of the alkene reagent. Reactions with the phenyl-substituted alkenes, styrene and 1,1-diphenylethene, require a more elevated temperature of 100 degrees C with styrene providing a mixture of the 2-phenylethyl and 1-phenylethyl products over 7 days. Although the reaction with 1,1-diphenylethene yields the magnesium 1,1-diphenylethyl derivative as the sole reaction product, only 64% conversion was achieved over a 21 day timeframe. Reactions with the alpha,omega-dienes, 1,5-hexadiene and 1,7-octadiene, provided divergent results. The initial 5-alkenyl magnesium reaction product of the shorter chain diene undergoes 5-exo-trig cyclisation via intramolecular carbomagnesiation to provide a cyclopentylmethyl derivative, which was shown by X-ray diffraction analysis to exist as a three-coordinate monomer. In contrast, 1,7-octadiene provided a mixture of two compounds, a magnesium oct-7-en-1-yl derivative and a dimagnesium-octane-1,4-diide, as a result of single or two-fold activation of the terminal C=C double bonds. The magnesium hydride was unreactive towards internal alkenes apart from the strained bicycle, norbornene, allowing the characterisation of the resultant three-coordinate magnesium norbornyl derivative by X-ray diffraction analysis. Computational analysis of the reaction between [(BDI)MgH](2) and 1-hexene using density functional theory (DFT) indicated that the initial Mg-H/C=C insertion process is rate determining and takes place at the intact magnesium hydride dimer. This exothermic reaction (Delta H = -14.1 kcal mol(-1)) traverses a barrier of 18.9 kcal mol(-1) and results in the rupture of the dinuclear structure into magnesium alkyl and hydride species. Although the latter three-coordinate hydride derivative may be prone to redimerisation, it can also provide a further pathway to magnesium alkyl species through its direct reaction with a further equivalent of 1-hexene, which occurs via a lower barrier of 15.1 kcal mol(-1). This Mg-H/C=C insertion reactivity provides the basis for the catalytic hydrosilylation of terminal alkenes with PhSiH3, which proceeds with a preference for the formation of the anti-Markovnikov organosilane product. Further DFT calculations reveal that the catalytic reaction is predicated on a sequence of Mg-H/C=C insertion and classical Si-H/Mg-C sigma-bond metathesis reactions, the latter of which, with a barrier height of 24.9 kcal mol(-1), is found to be rate determining