Publications by authors named "Maria Valeri"

13 Publications

  • Page 1 of 1

Nocturnal gibberellin biosynthesis is carbon dependent and adjusts leaf expansion rates to variable conditions.

Plant Physiol 2021 Feb;185(1):228-239

PLANTLAB, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa 56127, Italy.

Optimal plant growth performance requires that the presence and action of growth signals, such as gibberellins (GAs), are coordinated with the availability of photo-assimilates. Here, we studied the links between GA biosynthesis and carbon availability, and the subsequent effects on growth. We established that carbon availability, light and dark cues, and the circadian clock ensure the timing and magnitude of GA biosynthesis and that disruption of these factors results in reduced GA levels and expression of downstream genes. Carbon-dependent nighttime induction of gibberellin 3-beta-dioxygenase 1 (GA3ox1) was severely hampered when preceded by reduced daytime light availability, leading specifically to reduced bioactive GA4 levels, and coinciding with a decline in leaf expansion rate during the night. We attributed this decline in leaf expansion mostly to reduced photo-assimilates. However, plants in which GA limitation was alleviated had significantly improved leaf expansion, demonstrating the relevance of GAs in growth control under varying carbon availability. Carbon-dependent expression of upstream GA biosynthesis genes (Kaurene synthase and gibberellin 20 oxidase 1, GA20ox1) was not translated into metabolite changes within this short timeframe. We propose a model in which the extent of nighttime biosynthesis of bioactive GA4 by GA3ox1 is determined by nighttime consumption of starch reserves, thus providing day-to-day adjustments of GA responses.
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http://dx.doi.org/10.1093/plphys/kiaa019DOI Listing
February 2021

[Structured implementation and high adherence to the ERAS program in colorectal surgery in two operating units of the ASUR Marche.]

Recenti Prog Med 2021 Jan;112(1):30-44

UOC Chirurgia Generale, Ospedale C. Urbani, Jesi (AN), Area Vasta 2.

Background: An Enhanced Recovery After Surgery (ERAS) program in colorectal surgery is able to significantly reduce the morbidity rates and postoperative hospital stay (LOS) related to the intervention. However, it is not clear what modalities and levels of implementation are necessary to achieve these results. The purpose of this work is to analyze the methods and results of the first year of implementation of the program in two centers of the Agenzia Sanitaria Unica Regionale (ASUR) Marche.

Materials: After a structured implementation pathway, characterized by the creation of a core team, field training, internal courses and coaching, the details of 196 consecutive cases of patients submitted to colorectal resection over a one-year period in two surgical units of the ASUR Marche were prospectively loaded in a database, considering over 50 variables including adherence to the individual items of the ERAS program. The primary outcomes were: overall and major morbidity, mortality and anastomotic dehiscence rates; secondary outcomes were: LOS, re-admission and re-intervention rates. The results of primary endpoints were evaluated by univariable and multivariable analyses with logistic regression and, thereafter, according to ERAS item adherence rate.

Results: After a median (interquartile range, IQR) follow-up of 40 (32-94) days, we recorded complications in 72 patients (overall morbidity 36.7%), major morbidity in 14 patients (7.1%), 6 deaths (mortality 3.1%), an anastomotic dehiscence in 9 cases (4.9%), median (IQR) overalll LOS 5 (3-7) days, 10 readmissions (5.1%) and 13 reoperations (6.7%). The mean adherence rate to the items of the ERAS program was 85.4%, showing a significant dose-effect curve for overall morbidity, major morbidity, anastomotic leakage and for overall LOS.

Discussion: The ERAS implementation methods in this project led to a high adherence (>80%) to the program items. All the results showed a significant improvement compared to the previous pre-implementation period and according to the adherence to program items rate.
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http://dx.doi.org/10.1701/3525.35122DOI Listing
January 2021

Arabidopsis phenotyping reveals the importance of alcohol dehydrogenase and pyruvate decarboxylase for aerobic plant growth.

Sci Rep 2020 10 7;10(1):16669. Epub 2020 Oct 7.

Institute of Agricultural Biology and Biotechnology, CNR, National Research Council, Via Moruzzi, 56124, Pisa, Italy.

Alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) are key to the establishment of the fermentative metabolism in plants during oxygen shortage. Most of the evidence that both ADH and PDC are required for plant tolerance to hypoxia comes from experiments performed by limiting oxygen in the environment, such as by exposing plants to gaseous hypoxia or to waterlogging or submergence. However, recent experiments have shown that hypoxic niches might exist in plants grown in aerobic conditions. Here, we investigated the importance of ADH and PDC for plant growth and development under aerobic conditions, long-term waterlogging and short-term submergence. Data were collected after optimizing the software associated with a commercially-available phenotyping instrument, to circumvent problems in separation of plants and background pixels based on colour features, which is not applicable for low-oxygen stressed plants due to the low colour contrast of leaves with the brownish soil. The results showed that the growth penalty associated with the lack of functional ADH1 or both PDC1 and PDC2 is greater under aerobic conditions than in hypoxia, highlighting the importance of fermentative metabolism in plants grown under normal, aerobic conditions.
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http://dx.doi.org/10.1038/s41598-020-73704-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7542448PMC
October 2020

Botrytis cinerea induces local hypoxia in Arabidopsis leaves.

New Phytol 2021 01 6;229(1):173-185. Epub 2020 Apr 6.

Institute of Agricultural Biology and Biotechnology, CNR, National Research Council, Via Moruzzi, 56124, Pisa, Italy.

Low oxygen availability often is associated with soil waterlogging or submergence, but may occur also as hypoxic niches in otherwise aerobic tissues. Experimental evidence assigns a role in Botrytis cinerea resistance to a group of oxygen-unstable Ethylene Response Factors (ERF-VII). Given that infection by B. cinerea often occurs in aerobic organs such as leaves, where ERF-VII stability should be compromised, we explored the possibility of local leaf hypoxia at the site of infection. We analyzed the expression of hypoxia-responsive genes in infected leaves. Confocal microscopy was utilized to verify the localization of the ERF-VII protein RAP2.12. Oxygen concentration was measured to evaluate the availability of oxygen (O ). We discovered that infection by B. cinerea induces increased respiration, leading to a drastic drop in the O concentration in an otherwise fully aerobic leaf. The establishment of a local hypoxic area results in stabilization and nuclear relocalization of RAP2.12. The possible roles of defence elicitors, ABA and ethylene were evaluated. Local hypoxia at the site of B. cinerea infection allows the stabilization of ERF-VII proteins. Hypoxia at the site of pathogen infection generates a nearly O -free environment that may affect the stability of other N-degron-regulated proteins as well as the metabolism of elicitors.
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http://dx.doi.org/10.1111/nph.16513DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7754360PMC
January 2021

ARGONAUTE1 and ARGONAUTE4 Regulate Gene Expression and Hypoxia Tolerance.

Plant Physiol 2020 01 29;182(1):287-300. Epub 2019 Jul 29.

PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, Via Guidiccioni 10, San Giuliano Terme,56017 Pisa, Italy

In plants, hypoxia can be induced by submergence, and the lack of oxygen impairs mitochondrial respiration, thus affecting the plant's energy status. Hypoxia has major effects on gene expression; these changes induce key responses that help meet the needs of the stressed plant. However, little is known about the possible role of RNA signaling in the regulation of gene expression under limited oxygen availability. Here, we report the contribution of ARGONAUTE1 (AGO1) to hypoxia-induced gene regulation in Arabidopsis (). Submergence induced changes in levels of the microRNAs miR2936 and miR398, but this had no obvious effects on their putative target mRNA levels. However, we found that plants are intolerant to submergence and transcriptome analysis identified genes whose regulation requires functional AGO1. Analysis of mutants affected in various branches of RNA signaling highlighted the convergence of AGO1 signaling with the AGO4-dependent RNA-directed DNA methylation (RdDM) pathway. AGO4-dependent RdDM represses the expression of () and alters its response to submergence. Remarkably, methylation of the second exon of is not only reduced in but also in plants overexpressing a constitutively stable version of the oxygen sensor RELATED TO APETALA2 12 (RAP2.12), indicating convergence of oxygen signaling with epigenetic regulation of gene expression. Therefore, our results identify a role for AGO1 and AGO4 RNA-silencing pathways in low-oxygen signaling in Arabidopsis.
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http://dx.doi.org/10.1104/pp.19.00741DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6945874PMC
January 2020

Gene Regulation and Survival under Hypoxia Requires Starch Availability and Metabolism.

Plant Physiol 2018 02 30;176(2):1286-1298. Epub 2017 Oct 30.

PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, 56017 San Giuliano Terme (Pisa), Italy

Plants respond to hypoxia, often caused by submergence, by expressing a specific set of genes that contribute to acclimation to this unfavorable environmental condition. Genes induced by low oxygen include those encoding enzymes for carbohydrate metabolism and fermentation, pathways that are required for survival. Sugar availability is therefore of crucial importance for energy production under hypoxia. Here, we show that Arabidopsis () plants require starch for surviving submergence as well as for ensuring the rapid induction of genes encoding enzymes required for anaerobic metabolism. The starchless mutant is highly susceptible to submergence and also fails to induce anaerobic genes at the level of the wild type. Treating wild-type plants under conditions inducing sugar starvation results in a weak induction of alcohol dehydrogenase and other anaerobic genes. Induction of gene expression under hypoxia requires transcription factors belonging to group VII ethylene response factors (ERF-VII) that, together with plant Cys oxidases, act as an oxygen-sensing mechanism. We show that repression of this pathway by sugar starvation occurs downstream of the hypoxia-dependent stabilization of ERF-VII proteins and independently of the energy sensor protein kinases SnRK1.1 (SNF1-related kinase 1.1).
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http://dx.doi.org/10.1104/pp.17.01002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5813553PMC
February 2018

Cytokines IL-17 and IL-22 in the host response to infection.

Pathog Dis 2016 12 2;74(9). Epub 2016 Dec 2.

Department of Microbiology and Molecular Genetics, University of California Irvine School of Medicine, Irvine, CA 92697-4025, USA

Cytokines IL-17 and IL-22 play pivotal roles in host defense against microbes and in the development of chronic inflammatory diseases. These cytokines are produced by cells that are often located in epithelial barriers, including subsets of T cells and innate lymphoid cells. In general, IL-17 and IL-22 can be characterized as important cytokines in the rapid response to infectious agents, both by recruiting neutrophils and by inducing the production of antimicrobial peptides. Although each cytokine induces an innate immune response in epithelial cells, their functional spectra are generally distinct: IL-17 mainly induces an inflammatory tissue response and is involved in the pathogenesis of several autoimmune diseases, whereas IL-22 is largely protective and regenerative. In this review, we compare IL-17 and IL-22, describing overlaps and differences in their cellular sources as well as their regulation, signaling, biological functions and roles during disease, with a focus on the contribution of these cytokines to the gut mucosal barrier during bacterial infection.
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http://dx.doi.org/10.1093/femspd/ftw111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5975231PMC
December 2016

Overexpression of the olive acyl carrier protein gene (OeACP1) produces alterations in fatty acid composition of tobacco leaves.

Transgenic Res 2016 Feb 11;25(1):45-61. Epub 2015 Nov 11.

Institute of Biosciences and Bioresources (IBBR), Research Division of Perugia, CNR, Via Madonna Alta 130, 06128, Perugia, Italy.

Taking into account that fatty acid (FA) biosynthesis plays a crucial role in lipid accumulation in olive (Olea europaea L.) mesocarp, we investigated the effect of olive acyl carrier protein (ACP) on FA composition by overexpressing an olive ACP cDNA in tobacco plants. The OeACP1.1A cDNA was inserted in the nucleus or in the chloroplast DNA of different tobacco plants, resulting in extensive transcription of the transgenes. The transplastomic plants accumulated lower olive ACP levels in comparison to nuclear-transformed plants. Moreover, the phenotype of the former plants was characterized by pale green/white cotyledons with abnormal chloroplasts, delayed germination and reduced growth. We suggest that the transplastomic phenotype was likely caused by inefficient olive ACP mRNA translation in chloroplast stroma. Conversely, total lipids from leaves of nuclear transformants expressing high olive ACP levels showed a significant increase in oleic acid (18:1) and linolenic acid (18:3), and a concomitant significant reduction of hexadecadienoic acid (16:2) and hexadecatrienoic acid (16:3). This implies that in leaves of tobacco transformants, as likely in the mesocarp of olive fruit, olive ACP not only plays a general role in FA synthesis, but seems to be specifically involved in chain length regulation forwarding the elongation to C18 FAs and the subsequent desaturation to 18:1 and 18:3.
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http://dx.doi.org/10.1007/s11248-015-9919-zDOI Listing
February 2016

Identification of a Monoclonal Antibody Against Pneumococcal Pilus 1 Ancillary Protein Impairing Bacterial Adhesion to Human Epithelial Cells.

J Infect Dis 2016 Feb 23;213(4):516-22. Epub 2015 Sep 23.

GSK Vaccines, Siena.

The adhesion of Streptococcus pneumoniae is a key step during colonization of human respiratory tract mucosae. Here we demonstrate that pneumococcal type I pilus significantly increases the adhesiveness of poorly adhering highly capsulated strains in vitro. Interestingly, preincubation of bacteria with antibodies against the major pilus backbone subunit (RrgB) or the adhesin component (RrgA) impaired pneumococcal association to human epithelial cells. Screening for anti-RrgA monoclonal antibodies specifically affecting the adhesive capacity of S. pneumoniae led to the identification of the monoclonal 11B9/61 antibody, which greatly reduced pilus-dependent cell contact. Proteomic-based epitope mapping of 11B9/61 monoclonal antibody revealed a well-exposed epitope on the D2 domain of RrgA as the target of this functional antibody. The data presented here confirm the importance of pilus I for S. pneumoniae pathogenesis and the potential use of antipilus antibodies to prevent bacterial colonization.
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http://dx.doi.org/10.1093/infdis/jiv461DOI Listing
February 2016

The Neisseria meningitidis ADP-Ribosyltransferase NarE Enters Human Epithelial Cells and Disrupts Epithelial Monolayer Integrity.

PLoS One 2015 21;10(5):e0127614. Epub 2015 May 21.

Vaccines & Diagnostics s.r.l.-a GSK company- Via Fiorentina 1, Siena, Italy.

Many pathogenic bacteria utilize ADP-ribosylating toxins to modify and impair essential functions of eukaryotic cells. It has been previously reported that Neisseria meningitidis possesses an ADP-ribosyltransferase enzyme, NarE, retaining the capacity to hydrolyse NAD and to transfer ADP-ribose moiety to arginine residues in target acceptor proteins. Here we show that upon internalization into human epithelial cells, NarE gains access to the cytoplasm and, through its ADP-ribosylating activity, targets host cell proteins. Notably, we observed that these events trigger the disruption of the epithelial monolayer integrity and the activation of the apoptotic pathway. Overall, our findings provide, for the first time, evidence for a biological activity of NarE on host cells, suggesting its possible involvement in Neisseria pathogenesis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0127614PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4440719PMC
February 2016

Pathogenic E. coli exploits SslE mucinase activity to translocate through the mucosal barrier and get access to host cells.

PLoS One 2015 19;10(3):e0117486. Epub 2015 Mar 19.

Novartis Vaccines and Diagnostics S.r.l., Via Fiorentina 1, Siena, Italy.

SslE is a zinc-metalloprotease involved in the degradation of mucin substrates and recently proposed as a potential vaccine candidate against pathogenic E. coli. In this paper, by exploiting a human in vitro model of mucus-secreting cells, we demonstrated that bacteria expressing SslE have a metabolic benefit which results in an increased growth rate postulating the importance of this antigen in enhancing E. coli fitness. We also observed that SslE expression facilitates E. coli penetration of the mucus favouring bacteria adhesion to host cells. Moreover, we found that SslE-mediated opening of the mucosae contributed to the activation of pro-inflammatory events. Indeed, intestinal cells infected with SslE-secreting bacteria showed an increased production of IL-8 contributing to neutrophil recruitment. The results presented in this paper conclusively designate SslE as an important colonization factor favouring E. coli access to both metabolic substrates and target cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0117486PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4366376PMC
April 2016

SslE elicits functional antibodies that impair in vitro mucinase activity and in vivo colonization by both intestinal and extraintestinal Escherichia coli strains.

PLoS Pathog 2014 May 8;10(5):e1004124. Epub 2014 May 8.

Novartis Vaccines and Diagnostics Srl, Siena, Italy.

SslE, the Secreted and surface-associated lipoprotein from Escherichia coli, has recently been associated to the M60-like extracellular zinc-metalloprotease sub-family which is implicated in glycan recognition and processing. SslE can be divided into two main variants and we recently proposed it as a potential vaccine candidate. By applying a number of in vitro bioassays and comparing wild type, knockout mutant and complemented strains, we have now demonstrated that SslE specifically contributes to degradation of mucin substrates, typically present in the intestine and bladder. Mutation of the zinc metallopeptidase motif of SslE dramatically impaired E. coli mucinase activity, confirming the specificity of the phenotype observed. Moreover, antibodies raised against variant I SslE, cloned from strain IHE3034 (SslEIHE3034), are able to inhibit translocation of E. coli strains expressing different variants through a mucin-based matrix, suggesting that SslE induces cross-reactive functional antibodies that affect the metallopeptidase activity. To test this hypothesis, we used well-established animal models and demonstrated that immunization with SslEIHE3034 significantly reduced gut, kidney and spleen colonization by strains producing variant II SslE and belonging to different pathotypes. Taken together, these data strongly support the importance of SslE in E. coli colonization of mucosal surfaces and reinforce the use of this antigen as a component of a broadly protective vaccine against pathogenic E. coli species.
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http://dx.doi.org/10.1371/journal.ppat.1004124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4014459PMC
May 2014

Methyl carnosate, an antibacterial diterpene isolated from Salvia officinalis leaves.

Nat Prod Commun 2013 Apr;8(4):429-30

Department for the Innovation in Biological, Agro-food and Forest systems, Laboratory of Plant Cytology and Biotechnology, Tuscia University, Largo dell'Università blocco D, 01100 Viterbo, Italy.

Ethanolic extracts of Salvia officinalis leaves demonstrated antibacterial activity against Bacillus cereus. Fractionation of the extracts led to the isolation of the most active antibacterial compound, which, from spectroscopic and LC-MS evidence, was proved to be the diterpene, methyl carnosate.
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April 2013