SEARCH FOR SLOWLY MOVING MAGNETIC MONOPOLES WITH THE MACRO DETECTOR

A search for slowly moving magnetic monopoles in the cosmic radiation was conducted from October 1989 to November 1991 using the large liquid scintillator detector subsystem of the first supermodule of the MACRO detector at the Gran Sasso underground laboratory. The absence of candidates established an upper limit on the monopole flux of 5.6 x 10(-15) cm-2 sr-1 s-1 at 90% confidence level in the velocity range of 10(-4) less than or similar to beta < 4 x 10(-3). This result places a new constraint on the abundance of monopoles trapped in our solar system

Measurement of vector boson production cross sections and their ratios using pp collisions at √s = 13.6 TeV with the ATLAS detector

Abstract available from publisher's website

Development of a DNA-based biosensor for the fast and sensitive detection of ochratoxin A in urine

In this paper, a novel DNA-based biosensor is proposed, which is based on paramagnetic microbeads carrying an ochratoxin A (OTA) capture aptamer. A sandwich-like detection complex is linked to the capture aptamer and is able to trigger, in presence of OTA, an isothermal rolling circle amplification (RCA) reaction. This latter generated autocatalytic units with a peroxidase activity (DNAzyme) that, in presence of a proper substrate, gave a blue-coloured product visible by the naked eye. The capture aptamer, blocked onto magnetic beads, allowed the specific capture of OTA in liquid samples. The modified detection aptamer, annealed to a circularized probe, was then used to detect the toxin capture event. Indeed, in the presence of OTA and an isothermal enzyme, the circular DNA was amplified, producing a single-stranded and tandem repeated long homologous copy of its sequence. In the DNA strand, a self-catalytic structure was formed with hemin as the catalytic core, inducing the development of blue colour in the presence of ABTS and hydrogen peroxide. The results showed that the biosensor has high sensitivity and selectivity for the detection of OTA, as low as 1.09 × 10−12 ng/mL. Moreover, the proposed biosensor was successfully used for the detection of OTA in naturally contaminated rat urine. Accuracy and repeatability data obtained in recovery experiments were satisfying, being recoveries &gt;95% with relative standard deviations in the range 3.6–15%. For the first time, an aptasensor was successfully applied to detect OTA in biological fluids. It can be used for mycotoxin biomonitoring and assessment of individual exposure

Metabarcoding analysis of <i>Phytophthora</i> diversity using genus-specific primers and 454 pyrosequencing

A metabarcoding method based on genus-specific primers and 454 pyrosequencing was utilized to investigate the genetic diversity of Phytophthora spp. in soil and root samples of potted plants, from eight nurseries. Pyrosequencing enabled the detection of 25 Phytophthora phylotypes distributed in seven different clades and provided a much higher resolution than a corresponding cloning/Sanger sequencing approach. Eleven of these phylotypes, including P. cactorum, P. citricola s.str., P. palmivora, P. palmivora-like, P. megasperma or P. gonapodyides, P. ramorum, and five putative new Phytophthora species phylogenetically related to clades 1, 2, 4, 6, and 7 were detected only with the 454 pyrosequencing approach. We also found an additional 18 novel records of a phylotype in a particular nursery that were not detected with cloning/Sanger sequencing. Several aspects confirmed the reliability of the method: (i) many identical sequence types were identified independently in different nurseries, (ii) most sequence types identified with 454 pyrosequencing were identical to those from the cloning/Sanger sequencing approach and/or perfectly matched GenBank deposited sequences, and (iii) the divergence noted between sequence types of putative new Phytophthora species and all other detected sequences was sufficient to rule out sequencing errors. The proposed method represents a powerful tool to study Phytophthora diversity providing that particular attention is paid to the analysis of 454 pyrosequencing raw read sequences and to the identification of sequence types

Species of the Colletotrichum gloeosporioides and C. boninense complexes associated with olive anthracnose

The taxonomic status of Colletotrichum gloeosporioides sensu lato (s.l.) associated with olive anthracnose is still undetermined and the pathogenic ability of this species complex is controversial. In the present study, isolates obtained from olive and provisionally identified as C. gloeosporioides s.l. on the basis of morphological and cultural features were reclassified using ITS and TUB2 as DNA barcode markers and referred to seven distinct species, recently separated within C. gloeosporioides (C. aenigma, C. gloeosporioides sensu stricto (s.s.), C. kahawae, C. queenslandicum, C. siamense and C. theobromicola) and C. boninense (C. karstii) species complexes. Furthermore, isolates of C. kahawae were ascribed to the subspecies ciggaro by analysing the GS gene. A single isolate, not in either of these two species complexes, was not identified at the species level. In pathogenicity tests on detached olive drupes some of these species, including C. aenigma, C. kahawae subsp. ciggaro, C. queenslandicum, C. siamense and C. karstii, were shown to be weakly pathogenic. Moreover, they were found very sporadically on olive. In contrast, some isolates of C. gloeosporioides s.s. and isolates of C. theobromicola proved to be virulent on both green and ripening olives. This study gives a better insight into both the aetiology and the epidemiology of olive anthracnose and might have implications for biosecurity and quarantine because C. theobromicola has never been reported in major European olive-producing countries

Community analysis of culturable sapwood endophytes from apulian olive varieties with different susceptibility to xylella fastidiosa

Endophytes are symptomless fungal and/or bacterial microorganisms found in almost all living plant species. The symbiotic association with their host plants by colonizing the internal tissues has endowed them as a valuable tool to suppress diseases, stimulate growth, and promote stress resistance. In this context, the study of culturable endophytes residing the sapwood of Apulian olives might be a promising control strategy for xylem colonizing pathogens as Xylella fastidiosa. To date, olive sapwood cultivable endophytes are still under exploration; therefore, this work pursues a study of cultivable endophytes occurrence variation in the sapwood of different olive varieties under the effect of seasonality, geographical coordinates, and X. fastidiosa infection status. Our study confirms the stability of sapwood endophytic culturable communities in the resistant olive variety and presents the seasonal and geographical fluctuation of olive trees’ sapwood endophytes. It also describes the diversity and occurrence frequency of fungal and bacterial genera, and finally retrieves some of the sapwood-inhabiting fungal and bacterial isolates, known as biocontrol agents of plant pathogens. Thus, the potential role of these bacterial and fungal isolates in conferring olive tree protection against X. fastidiosa should be further investigated