Chiral selectivity of porphyrin-ZnO nanoparticle conjugates

Recognition of enantiomers is one of the most arduous challenges in chemical sensor development. Although several chiral systems exist, their effective exploitation as the sensitive layer in chemical sensors is hampered by several practical implications that hinder stereoselective recognition in solid state. In this paper, we report a new methodology to efficiently prepare chiral solid films, by using a hybrid material approach where chiral porphyrin derivatives are grafted onto zinc oxide nanoparticles. Circular dichroism (CD) evidences that the solid-state film of the material retains supramolecular chirality due to porphyrin interactions, besides an additional CD feature in correspondence of the absorbance of ZnO (375 nm), suggesting the induction of chirality in the underlying zinc oxide nanoparticles. The capability of hybrid material to detect and recognize vapors of enantiomer pairs was evaluated by fabricating gas sensors based on quartz microbalances. Chiral films of porphyrin on its own were used for comparison. The sensor based on functionalized nanostructures presented a remarkable stereoselectivity in the recognition of limonene enantiomers, whose ability to intercalate in the porphyrin layers makes this terpene an optimal chiral probe. The chiroptical and stereoselective properties of the hybrid material confirm that the use of porphyrin-capped ZnO nanostructures is a viable route for the formation of chiral selective surfaces. © 2019 American Chemical Society

Molecular characterization of Neisseria gonorrhoeae on non-cultured specimens from multiple anatomic sites

Introduction. The aim was to characterize Neisseria gonorrheae collected from multiple sites in the same patient without a cultured strain. The use of N. gonorrhoeae multiantigen sequence typing (NG-MAST) together with the gene sequence analysis of antimicrobial resistance (AMR) target genes permit to depict these samples.Materials and methods. Seventeen genital and extra-genital samples from eight patients (7 were men who have sex with men, MSM, and 1 women who have sex with men, WSM) with gonorrhoea symptoms were analyzed.For 7, of the 8 patients, conventional culture method has been used to identify gonorrhoea. All the samples were tested with the rapid molecular method CEPHEID. Amplification and sequencing of porB and tbpB, to identify the Sequence Type (ST) by NG-MAST, and penA, mtrR, porB1b, ponA genes were also performed.Antimicrobial susceptibility by Etest, for the available culture positive samples, was carried out.Results. For 7 patients it was obtained the ST (Sequence Type) and for 6 the complete sequence analysis of the antimicrobial resistance target genes. For the majority of them, samples collected from multiple sites confirm the presence of the same gonorrhoea strain. In particular, for 5 patients the same STs and changes in the AMR target genes were identified.Conclusion. Molecular characterization on non-cultured or culture negative specimens for gonorrhoea permit to predict the presence of the same strain in the patients with infection in multiple anatomic sites and the genetic antimicrobial susceptibility pattern

In vitro and ex vivo evaluation of the anti-Giardia duodenalis activity of the supernatant of SLAB51 (SivoyTM)

The effects on Giardia duodenalis growth (G), adherence (A), and viability (V) of SivoyTM probiotic supernatant were evaluated in vitro and ex vivo. SivoyTM (101 UFC) was in vitro cultured and the obtained supernatant was filtered, adjusted at pH 7, and added (100 μl/ml) as such (FS) or after heat-treatment to G. duodenalis (5×104) cultures in TYI-S-33 medium. Negative and metronidazole 20 μg/ml (M) treated controls were used. Ex vivo, five- 1 cm long mice duodenal portions were cultivated in standard conditions with 5X105 G. duodenalis trophozoites/ml, while to further five duodenal portions similarly cultured and infected, FS 200μl was added. After 12 and 18h, samples were fixed in 10% buffered formalin and histologically processed to score Giardia infection and cell damage. Cells proliferation/apoptosis were scored by TUNEL, Caspase–3, and Ki67 tests. All data, in triplicate, were statistically evaluated (P< 0.05). Results showed that FS significantly reduced Giardia G and V respect to negative controls but its efficacy was lower than that of M, while the inhibition of A was similar to that of M. Moreover, the effects of FS were significantly lowered by heat-treatment and the reduction was statistically higher at 90°C than at 56°C, indicating a heat-sensitive nature of active FS compounds. In ex vivo trials, in intestinal sections treated with FS respect to untreated controls viable G. duodenalis trophozoites and enterocyte TUNEL+ and Caspase-3 expression were significantly reduced, while enterocyte Ki67 expression was significantly increased, confirming the anti-G. duodenalis activity of FS observed in vitro

Palladium complexes based nanogravimetric sensors for carbon monoxide detection

Two palladium complexes, the [Pd( 2-ol)(8-(di-tert-butylphosphinooxy)quinoline)] and [Pd( 2-ol)(8-(di-tert-butylphosphinooxy)-2-methylquinoline)], have been used as sensing materials to functionalized quartz crystal microbalances (QCM). The developed sensors have been tested to determine carbonmonoxide in air. The reversible binding of CO observed in CH2Cl2solution for both complexes is retainedin the solid state. The functionalized QCMs showed good reproducibility and sensitivity toward CO detec-tion. While CO detection was not influenced by the presence of molecular hydrogen and methane, thehumidity reduced the sensors sensitivity, although the functionalized QCMs were still able to discriminateCO

EVALUATION OF TRICHINELLA PSEUDOSPIRALIS AND TOXOPLASMA GONDII INFECTION IN FREE RANGING CORVIDS FROM THE PROVINCE OF PISA

Magpies (Pica pica) and hooded crows (Corvus corone cornix) are scavenger birds feeding on carcasses, arthropods, vegetables, small preys and food waste. In Italy, they tend to remain in the same territory and establish large populations both in urban and rural environments. For these reasons, these birds have a potential role as sentinels for the spread of Toxoplasma gondii in a given area. Trichinella pseudospiralis has been previously reported in corvids. In the present study, 798 free ranging corvids, including 678 magpies and 120 hooded crows deceased following a program of population size reduction of the province of Pisa, were examined for T. pseudospiralis and T. gondii infections. More specifically, sera from 651 magpies and 120 hooded crows were examined by IFAT for antibodies specific to T. gondii. In seropositive birds, the heart was homogenized and DNA was extracted to perform a nested polymerase chain reaction (nPCR) detection method for B1 gene of T. gondii and genotyping for SAG. In the case of Trichinella, breast muscle samples (50 g each) from 678 magpies and 91 hooded crows were tested by an artificial digestion method. After digestion, eventually recovered larvae were processed for molecular typing. Data were statistically analysed (p <0.05). Forty-five, 41 magpies and 4 hooded crows, out of the 771 examined animals (5.8%) scored positive for T. gondii with antibody titers ranging from 1: 25 to 1:100. Seropositivity to T. gondii was not statistically different between magpies and hooded crows. T. gondii DNA was detected in 15 out of 45 heart samples and the occurrence of genotypes II and III of T. gondii was evidenced. No Trichinella larvae were detected in muscle samples. This is the first report of T. gondii infection in corvids in Italy

Molecular characterization of Neisseria gonorrhoeae on non-cultured specimens from multiple anatomic sites

Introduction. The aim of this study was to molecularly characterize Neisseria gonorrhoeae on non-cultured specimens collected from multiple anatomic sites. N. gonorrhoeae multiantigen sequence typing (NG-MAST) together with the gene sequence analysis of antimicrobial resistance (AMR) target genes were used. Materials and methods. Seventeen genital and extra-genital samples from eight patients (7 were men who have sex with men, MSM, and 1 women who have sex with men, WSM) with gonorrhoea symptoms were analyzed. For 7, of the 8 patients, conventional culture method has been used to identify gonorrhoea. All the samples were tested with the rapid molecular method CEPHEID. Amplification and sequencing of porB and tbpB, to identify the Sequence Type (ST) by NG-MAST, and penA, mtrR, porB1b, ponA genes were also performed. Antimicrobial susceptibility by Etest, for the available culture positive samples, was carried out. Results. For 7 patients the ST was obtained and for 6 the complete sequence analysis of the AMR target genes was also defined. For the majority of them, samples collected from multiple sites (oropharynx, rectum, vaginal and urethra) confirm the presence of the same gonorrhoea strain. In particular, for 5 patients the same STs and changes in the AMR target genes were identified. Conclusion. Molecular characterization on non-cultured or culture negative specimens for gonorrhoea can successfully be applied directly to genital and extra-genital samples. Thus permit to identify the presence of the same strain in patients with gonorrhoea infection in multiple anatomic sites and to predict the antimicrobial susceptibility pattern

Mangime commerciale disidratato all’origine di un focolaio di salmonellosi sostenuto da diversi sierotipi in un canile municipale in Toscana

Il lavoro descrive un importante focolaio di salmonellosi in cani ospitati in un canile municipale. Durante il focolaio, 174 campioni di feci “diarroiche” e “normali” e due lotti di mangime in uso al canile, sono stati sottoposti ad analisi per la ricerca di Salmonella. Venticinque cani su 41 (60,9%), sono risultati positivi ad almeno una coprocoltura, con una incidenza per campionamento compresa tra il 12,5 ed il 34%. Nove campioni di mangime su 10 sono risultati positivi. In totale, nei campioni di feci e di mangime, sono stati isolati 10 differenti sierotipi di Salmonella: l’identificazione mediante pulsed-field gel electrophoresis (PFGE), ha riportato un’elevata similarità nell’ambito del sierotipo, tra gli isolati da feci e mangime di Salmonella Montevideo, Muenster e Worthington

Contaminated commercial dehydrated food as source of multiple Salmonella serotypes outbreak in a municipal kennel in Tuscany

The authors describe a large outbreak of canine salmonellosis in a municipal kennel in Tuscany. During the outbreak, 174 samples of ‘diarrhetic’ and ‘normal’ faeces and two batches of commercial dehydrated dog food were cultured for pathogenic bacteria. The results of 25, out of a total of 41 dogs (60.9%) revealed at least one faecal sample as being positive for Salmonella; incidence per sampling ranged from 12.5% to 34%. Nine of 10 samples of dehydrated food were positive. Ten totally different serotypes were isolated from dry food and faeces: the results of the pulsed-field gel electrophoresis referred to similarity between the Salmonella Montevideo, Muenster and Worthington isolates recovered from both the food and canine faecal samples

Health risk evaluation associated to Planktothrix rubescens: An integrated approach to design tailored monitoring programs for human exposure to cyanotoxins

Increasing concern for human health related to cyanotoxin exposure imposes the identification of pattern and level of exposure; however, current monitoring programs, based on cyanobacteria cell counts, could be inadequate. An integrated approach has been applied to a small lake in Italy, affected by Planktothrix rubescens blooms, to provide a scientific basis for appropriate monitoring program design. The cyanobacterium dynamic, the lake physicochemical and trophic status, expressed as nutrients concentration and recycling rates due to bacterial activity, the identification/quantification of toxic genotype and cyanotoxin concentration have been studied. Our results indicate that low levels of nutrients are not a marker for low risk of P. rubescens proliferation and confirm that cyanobacterial density solely is not a reliable parameter to assess human exposure. The ratio between toxic/nontoxic cells, and toxin concentrations, which can be better explained by toxic population dynamic, are much more diagnostic, although varying with time and environmental conditions. The toxic fraction within P. rubescens population is generally high (30-100%) and increases with water depth. The ratio toxic/non-toxic cells is lowest during the bloom, suggesting a competitive advantage for non-toxic cells. Therefore, when P. rubescens is the dominant species, it is important to analyze samples below the thermocline, and quantitatively estimate toxic genotype abundance. In addition, the identification of cyanotoxin content and congeners profile, with different toxic potential, are crucial for risk assessment. (C) 2009 Elsevier Ltd. All rights reserved