Publications by authors named "Uriel Maor"

10 Publications

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Host Factors Modulating Ochratoxin A Biosynthesis during Fruit Colonization by .

J Fungi (Basel) 2020 Dec 28;7(1). Epub 2020 Dec 28.

Institute of Postharvest and Food Sciences, The Volcani Center, Agricultural Research Organization, Rishon LeZion 7528809, Israel.

is a strong and consistent ochratoxin A (OTA) producer and considered to be the main source of this toxic metabolite in grapes and grape products such as wine, grape juice and dried vine fruit. OTA is produced under certain growth conditions and its accumulation is affected by several environmental factors, such as growth phase, substrate, temperature, water activity and pH. In this study, we examined the impact of fruit host factors on regulation and accumulation of OTA in colonized grape berries, and assessed in vitro the impact of those factors on the transcriptional levels of the key genes and global regulators contributing to fungal colonization and mycotoxin synthesis. We found that limited sugar content, low pH levels and high malic acid concentrations activated OTA biosynthesis by , both in synthetic media and during fruit colonization, through modulation of global regulator of secondary metabolism, and OTA gene cluster expression. These findings indicate that fruit host factors may have a significant impact on the capability of to produce and accumulate OTA in grapes.
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http://dx.doi.org/10.3390/jof7010010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823970PMC
December 2020

Functional roles of LaeA, polyketide synthase, and glucose oxidase in the regulation of ochratoxin A biosynthesis and virulence in Aspergillus carbonarius.

Mol Plant Pathol 2021 01 10;22(1):117-129. Epub 2020 Nov 10.

Institute of Postharvest and Food Sciences, The Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel.

Aspergillus carbonarius is the major producer of ochratoxin A (OTA) among Aspergillus species, but the contribution of this secondary metabolite to fungal virulence has not been assessed. We characterized the functions and addressed the roles of three factors in the regulation of OTA synthesis and pathogenicity in A. carbonarius: LaeA, a transcriptional factor regulating the production of secondary metabolites; polyketide synthase, required for OTA biosynthesis; and glucose oxidase (GOX), regulating gluconic acid (GLA) accumulation and acidification of the host tissue during fungal growth. Deletion of laeA in A. carbonarius resulted in significantly reduced OTA production in colonized nectarines and grapes. The ∆laeA mutant was unable to efficiently acidify the colonized tissue, as a direct result of diminished GLA production, leading to attenuated virulence in infected fruit compared to the wild type (WT). The designed Acpks-knockout mutant resulted in complete inhibition of OTA production in vitro and in colonized fruit. Interestingly, physiological analysis revealed that the colonization pattern of the ∆Acpks mutant was similar to that of the WT strain, with high production of GLA in the colonized tissue, suggesting that OTA accumulation does not contribute to A. carbonarius pathogenicity. Disruption of the Acgox gene inactivated GLA production in A. carbonarius, and this mutant showed attenuated virulence in infected fruit compared to the WT strain. These data identify the global regulator LaeA and GOX as critical factors modulating A. carbonarius pathogenicity by controlling transcription of genes important for fungal secondary metabolism and infection.
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http://dx.doi.org/10.1111/mpp.13013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7749749PMC
January 2021

Surface analysis of ancient parchments via the EVA film: The Aleppo Codex.

Anal Biochem 2020 09 7;604:113824. Epub 2020 Jul 7.

Department of Chemistry, Materials and Chemical Engineering ''Giulio Natta'', Politecnico di Milano, Via Mancinelli 7, Milano, 20131, Italy. Electronic address:

The margins of several pages of the Aleppo codex have been found to be corroded and contaminated by diffuse maculae. In order to understand the origin of this decay these margins have been analysed by applying EVA (ethylene vinyl acetate plastic embedded with strong cation and anion exchangers and mixed with C and C hydrophobic resins) diskettes for harvesting surface material. The captured compounds have been eluted, digested with trypsin and analysed by nano-HPLC-MS. Three major strains of Aspergillus have been identified, namely Aspergillus fumigatus, Aspergillus pseudoglaucus, Aspergillus amstelodami, together with a lactobacillus strain and human keratins. The novelty of this investigation is that for the first time the EVA technology has been applied to ancient parchments in the absence of mechanical deformation or distortion that could be induced if there had been water exchange between the EVA diskettes and the parchment. These findings should help curators to find suitable restoration protocols for these precious documents belonging to the world Cultural Heritage.
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http://dx.doi.org/10.1016/j.ab.2020.113824DOI Listing
September 2020

"1984": What Orwell could not predict. Proteomic analysis of his scripts.

Electrophoresis 2020 11 9;41(21-22):1931-1940. Epub 2020 Jun 9.

Department of Chemistry, Materials and Chemical Engineering, Milano, Italy.

George Orwell, fighter for the Republican Army during the Spanish Civil War, was shot through the throat by a sniper on 20th May 1937 and nearly killed. After receiving only a summary external treatment, on the 29th, he was cured in a Barcelona hospital where he was infected by the Koch bacillus. After fleeing from Spain on 23rd June 1937, he repaired to his cottage in Wallington, Hertfordshire, wherefrom he wrote a letter to Sergey Dynamov, Editor of Soviet journal "Foreign Literature." This typewritten letter was analyzed by application of five EVA strips (ethylene vinyl acetate studded with strong cation and anion and with C and C resins; four on the corners and one over his signature), searching for biological traces. Upon elution of the captured biologicals, trypsin digestion and Orbitrap Fusion trihybrid mass spectrometer analyses, three of the five strips yielded clear traces of six unique proteins (via proteotypic peptides) of the tuberculosis bacterium. Additionally, MALDI TOF analysis of saliva of a tuberculosis patient and the EVA strip eluates gave a spectrum of 14 peptide bands (Mr 2700 to 6700 Da range) coincident between the two samples, thus, fully confirming Orwell's pathology. These results are attributed to saliva traces on Orwell's fingertips and to the fact that the letter was written on 2nd July 1937, when Orwell's pathology was at its peak.
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http://dx.doi.org/10.1002/elps.202000063DOI Listing
November 2020

The pH-Responsive Transcription Factor PacC Governs Pathogenicity and Ochratoxin A Biosynthesis in .

Front Microbiol 2020 13;11:210. Epub 2020 Feb 13.

Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel.

Pathogenic fungi must respond effectively to changes in environmental pH for successful host colonization, virulence and toxin production. is a mycotoxigenic pathogen with the ability to colonize many plant hosts and secrete ochratoxin A (OTA). In this study, we characterized the functions and addressed the role of PacC-mediated pH signaling in pathogenicity using designed gene knockout mutant. Δ mutant displayed an acidity-mimicking phenotype, which resulted in impaired fungal growth at neutral/alkaline pH, accompanied by reduced sporulation and conidial germination compared to the wild type (WT) strain. The Δ mutant was unable to efficiently acidify the growth media as a direct result of diminished gluconic and citric acid production. Furthermore, loss of resulted in a complete inhibition of OTA production at pH 7.0. Additionally, Δ mutant exhibited attenuated virulence compared to the WT toward grapes and nectarine fruits. Reintroduction of gene into Δ mutant restored the WT phenotype. Our results demonstrate important roles of PacC of in OTA biosynthesis and in pathogenicity by controlling transcription of genes important for fungal secondary metabolism and infection.
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http://dx.doi.org/10.3389/fmicb.2020.00210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7031272PMC
February 2020

De re metallica. Johannes Kepler and alchemy.

Talanta 2019 Nov 26;204:82-88. Epub 2019 May 26.

Department of Chemistry, Materials and Chemical Engineering ''Giulio Natta'', Politecnico di Milano, Via Mancinelli 7, Milano, 20131, Italy. Electronic address:

The application of analytical chemistry to the exploration of the World Cultural Heritage represents a major challenge in that most protocols and strategies are invasive and require micro-sampling. We report a novel methodology for harvesting material deposited on the surface of ancient documents while avoiding their damage or contamination. The technology here described relates to the capture of metals on these specimens. It is based on the use of plastic films (ethylene vinyl acetate, EVA) impregnated with different metal chelators (sodium 2,3-dimercapto-1-propanesulfonate, DMPS, meso-2,3-dimercaptosuccinic acid, DMSA and ethylene diamino tetra acetic acid, EDTA, as calcium salt), for harvesting from surfaces of different supports potential traces of metals therein deposited. The EVA film technology has been used to explore the pages of a manuscript written by Kepler concerning the movements of the moon and catalogued under the title "Hipparchus" at the Archives of the Russian Academy of Sciences (St. Petersburg branch). The EVA-based chelating diskettes were able to capture very significant amounts of different metals, namely: Au, Ag, Hg, As, Pb, suggesting that Kepler, well known as astronomer, astrologist, mathematician and Lutheran theologian, might have started practicing alchemy, a pseudo-chemical science he had learned from his colleague Tycho Brahe in Prague.
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http://dx.doi.org/10.1016/j.talanta.2019.05.094DOI Listing
November 2019

Noninvasive wearable sensor for indirect glucometry.

Electrophoresis 2018 09 30;39(18):2344-2350. Epub 2018 Apr 30.

Department of Chemistry, Politecnico di Milano, Milano, Italy.

A noninvasive mini-sensor for blood glucose concentration assessment has been developed. The monitoring is performed by gently pressing a wrist or fingertip onto the chemochromic mixture coating a thin glass or polymer film positioned on the back panel of a smart watch with PPG/HRM (photoplethysmographic/heart rate monitoring sensor). The various chemochromic components measure the absolute values of the following metabolites present in the sweat: acetone, acetone beta-hydroxybutirate, aceto acetate, water, carbon dioxide, lactate anion, pyruvic acid, Na and K salts. Taken together, all these parameters give information about blood glucose concentration, calculated via multivariate analysis based on neural network algorithms built into the sensor. The Clarke Error Grid shows an excellent correlation between data measured by the standard invasive glucose analyser and the present noninvasive sensor, with all points aligned along a 45-degree diagonal and contained almost exclusively in sector A. Graphs measuring glucose levels five times a day (prior, during and after breakfast and prior, during and after lunch), for different individuals (males and females) show a good correlation between the two curves of conventional, invasive meters vs. the noninvasive sensor, with an error of ±15%. This novel, noninvasive sensor for indirect glucometry is fully miniaturized, easy to use and operate and could represent a valid alternative in clinical settings and for individual, personal users, to current, invasive tools.
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http://dx.doi.org/10.1002/elps.201700424DOI Listing
September 2018

A miniaturized sensor for detection of formaldehyde fumes.

Electrophoresis 2017 09 20;38(17):2168-2174. Epub 2017 Jun 20.

Department of Chemistry, Materials and Chemical Engineering ''Giulio Natta'', Politecnico di Milano, Milano, Italy.

A miniaturized chemical sensor is here described for the analysis of environmental pollutants (VOC: volatile organic chemicals). It is used for remote detection of formaldehyde (FA) fumes in the atmosphere, and is based on the redox reaction between FA and silver nitrate. The sensor is worn as a bracelet and the data acquired are transferred via a Bluetooth channel to a smartphone. A dedicated software transforms the signal from a grey to a color scale. The signal response has been assessed over low (20 to 120 ppb) as well as higher (1-15 ppm range) levels. The sensor has been applied to monitor potential FA fumes of some artwork in the Summer Palace in Beijing and the modifications induced by FA treatment on a precious Stradivarius violin. The performance of this novel sensor is compared with a commercial apparatus widely adopted, namely the Honeywell MultiRAE Lite wireless portable multi-gas monitor (pumped model).
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http://dx.doi.org/10.1002/elps.201600559DOI Listing
September 2017

Unearthing Bulgakov's trace proteome from the Master i Margarita manuscript.

J Proteomics 2017 01 29;152:102-108. Epub 2016 Oct 29.

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via Mancinelli 7, Milano 20131, Italy. Electronic address:

Ten pages, selected from a total of 127, of the last manuscript of Master i Margarita, written by Bulgakov in the last four years of his life, have been analysed in order to harvest and identify any trace proteome left on the margin by the novelist, in the hope of finding biomarkers of his fatal nephrotic syndrome. To that aim, we prepared a special ethyl-vinyl acetate film as binder of ground AG 501 Bio-Rad mix-bed strong cation/strong anion exchange resins for adsorbing any protein left on the margins of the pages via saliva and/or sweat. After eluting, digesting and interrogating the peptides by LC-MS/MS, we could identify three proteins, periostin, N-acetyl-β-glucosaminidase and nephrin, reported as biomarkers of renal pathologies. Additionally a further 29 unique gene products, of saliva and skin origin, have been identified, together with two bacterial proteins. The novel method here reported could be safely applied to any other research on manuscripts stored in public libraries and repositories of the World Cultural Heritage.

Significance: The present manuscript aims at finding proteomics traces in a 75-year old manuscript in order to confirm the health state of the author. In the case of Bulgakov it was known that he died of renal disease, possibly leaving traces and/or biomarkers of this pathology on the margins of the pages analysed. Three proteins, stated to be biomarkers of nephrotic syndrome, could be identified. In order not to contaminate the manuscript pages with resin particles, we have devised a novel harvesting film, by which strong cation and anion exchangers are embedded in ethyl-vinyl acetate foils. It is felt that this technology could be safely applied to other specimens belonging to the Word Heritage.
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http://dx.doi.org/10.1016/j.jprot.2016.10.019DOI Listing
January 2017

Maestro, Marguerite, morphine: The last years in the life of Mikhail Bulgakov.

J Proteomics 2016 Jan 3;131:199-204. Epub 2015 Nov 3.

Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via Mancinelli 7, Milano 20131, Italy. Electronic address:

Unlabelled: The manuscript pages of the final draft of Master i Margarita, the masterpiece by Mikhail Bulgakov, written in the last four years of his life (1936-1940), have been treated with a mixture of chromatographic beads, namely a strong cation exchanger and a C8 resin. Potential substances captured by the beads, after harvesting them, were eluted with a mixture of isopropyl alcohol, dichloromethane and ammonium hydroxide and the eluate subjected to GC-MS analysis in order to detect the presence, if any, of drugs, due to the fact that the writer suffered intense pains caused by an inherited nephrotic syndrome. Indeed all the pages under investigation (a total of ten, taken at random among 127 foils) contained traces of morphine, from as little as 5 up to 100ng/cm(2). In addition to the intact drug, we could detect one of its metabolites, namely 6-O-acetyl morphine. The significance of these findings in terms of a possible improvement of the novel and in terms of drug use (or abuse) in the modern world is discussed and evaluated.

Biological Significance: The extraction of metabolites/proteins from the surface of the original manuscript pages of Bulgakov masterpiece Master i Margarita has permitted to monitor his health state and intake of medicaments over the last four years of his life. We have ascertained that: (1) he was assuming large doses of morphine as pain killers; (2) he was affected by a nephrotic syndrome, since we could identify three proteins known as biomarkers of this pathology. The double extraction procedure here reported could open up a novel field of investigation of (relatively) ancient manuscripts for metabolome/proteome analysis on the health status of the writer/artist.
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http://dx.doi.org/10.1016/j.jprot.2015.11.002DOI Listing
January 2016