Papers by Andrea C. Rinaldi
... Page 6. Ornella Comandini, Andrea C. Rinaldi, Thomas W. Kuyper 170 Münzenberger et al. ... No... more ... Page 6. Ornella Comandini, Andrea C. Rinaldi, Thomas W. Kuyper 170 Münzenberger et al. ... Notes Sphaerosporella Molina et al., 1992 Meotto and Carraturo, 1988; de Román and de Miguel, 2005b Danielson, 1984b Hansen and Pfister, 2006 2 ...
Thousands of ectomycorrhizal (ECM) fungal species exist, but estimates of global species richness... more Thousands of ectomycorrhizal (ECM) fungal species exist, but estimates of global species richness of ECM fungi differ widely. Many genera have been proposed as being ECM, but in a number of studies evidence for the hypothesized ECM habit is lacking. Progress in estimating ECM species richness is therefore slow. In this paper we have retrieved studies providing evidence for the ECM habit of fungal species and for the identification of the mycobiont(s) in specific ECM associations, using published and web-based mycorrhiza literature. The identification methods considered are morphoanatomical characterization of naturally occurring ECMs, pure culture synthesis, molecular identification, and isotopic evidence. In addition, phylogenetic information is also considered as a relevant criterion to assess ECM habit. Of 343 fungal genera for which an ECM status has been alleged, about two thirds have supportive published evidence or ECM status can be at least hypothesized. For the remaining ta...
Plants, 2021
Well over 1% of all flowering plants are parasites, obtaining all or part of the nutrients they n... more Well over 1% of all flowering plants are parasites, obtaining all or part of the nutrients they need from other plants. Among this extremely heterogeneous assemblage, the Cytinaceae form a small group of holoparasites, with Cytinus as the main representative genus. Despite the small number of known species and the fact that it doesn’t attack crops or plants of economic importance, Cytinus is paradigmatic among parasitic plants. Recent research has indeed disclosed many aspects of host–parasite interactions and reproductive biology, the latter displaying a vast array of adaptive traits to lure a range of animal pollinators. Furthermore, analysis of biological activities of extracts of the most common species of Cytinus has provided evidence that this plant could be a valuable source of compounds with high potential in key applicative areas, namely food production (nutraceuticals) and the development of antimicrobial therapeutics. This article offers a complete overview of our current...
Antibiotics, 2020
The ability of many anti-microbial peptides (AMPs) to modulate the host immune response has highl... more The ability of many anti-microbial peptides (AMPs) to modulate the host immune response has highlighted their possible therapeutic use to reduce uncontrolled inflammation during chronic infections. In the present study, we examined the anti-inflammatory potential of the semi-synthetic peptide lin-SB056-1 and its dendrimeric derivative (lin-SB056-1)2-K, which were previously found to have anti-microbial activity against Pseudomonas aeruginosa in in vivo-like models mimicking the challenging environment of chronically infected lungs (i.e., artificial sputum medium and 3-D lung mucosa model). The dendrimeric derivative exerted a stronger anti-inflammatory activity than its monomeric counterpart towards lung epithelial- and macrophage-cell lines stimulated with P. aeruginosa lipopolysaccharide (LPS), based on a marked decrease (up to 80%) in the LPS-induced production of different pro-inflammatory cytokines (i.e., IL-1β, IL-6 and IL-8). Accordingly, (lin-SB056-1)2-K exhibited a stronger...
BMC Complementary and Alternative Medicine, 2019
Background: Cytinus is small genus of endophytic parasitic plants distributed in South Africa, Ma... more Background: Cytinus is small genus of endophytic parasitic plants distributed in South Africa, Madagascar, and in the Mediterranean region. In the latter area, two species occur, Cytinus hypocistis and C. ruber, distinguished by both morphological characters and ecological traits. We characterized the ethanolic and aqueous extracts obtained from the inflorescences of C. hypocistis and C. ruber collected in Sardinia, Italy, and explored their tannin content, antioxidant properties and antimicrobial activities. Methods: Total phenolic contents were determined by Folin-Ciocalteu spectrophotometric method. Tannin content was determined by HPLC. Antioxidant activity of the extracts was tested with both electron transfer-based (FRAP, TEAC, DPPH) and spectrophotometric HAT methods (ORAC-PYR). The antimicrobial activities of extracts/ compounds were evaluated using the broth microdilution method. The bactericidal activity was evaluated using the time-kill method. Biofilm formation was evaluated by crystal violet (CV) staining assay. Results: Characterization of the tannin profile of C. hypocistis and C. ruber revealed a significant amount of gallotannins, in particular 1-O-galloyl-β-D-glucose. In addition, pentagalloyl-O-β-D-glucose was present in all extracts, reaching the concentration of 0.117 g/kg in the ethanolic extract of C. hypocistis. C. hypocistis extracts displayed a strongest antioxidant activity than C. ruber extracts. Three Gram-positive bacterial species tested (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium) resulted sensitive to both Cytinus extracts, with MICs ranging from 125 to 500 μg/ml for aqueous extracts and from 31.25 to 250 μg/ml for ethanolic extracts; on the contrary, Gram-negative strains (Pseudomonas aeruginosa and Klebsiella pneumoniae) were not affected by Cytinus extracts. Intriguingly, we observed the suppressive activity of ethanolic extracts of C. hypocistis and C. ruber on biofilm formation of S. epidermidis. Experiments performed with synthetic compounds indicated that pentagalloyl-O-β-D-glucose is likely to be one of the active antimicrobial components of Cytinus extracts. Conclusions: These findings show that Cytinus extracts have antimicrobial and antioxidant activities, suggesting a possible application of Cytinus as sources of natural antimicrobials and antioxidants.
Frontiers in physiology, 2017
Caves are an extreme environment for humans because of the high humidity, mud, darkness, and slip... more Caves are an extreme environment for humans because of the high humidity, mud, darkness, and slippery conditions. Explorations can last many hours or even days, and require extensive climbing and ropework. Very little is known about the physical capacity of cavers and their energy expenditure (EE) during caving. The physical capacity of 17 (7 females) expert cavers (age 43.9 ± 7.3 years) was assessed during an incremental cycle-ergometer test (IET) with gas exchange analysis. Moreover, a wearable metabolic band (Armband Fit Core) was used to estimate their EE during caving. In terms of physical capacity, the IET showed that cavers had a maximum oxygen uptake (VO) of 2,248.7 ± 657.8 ml·min(i.e., 32.4 ± 6.4 ml·kg·min), while anaerobic threshold (AT) occurred on average at 74.5% of VO. Results from caving sessions provided an average time spent in cave of 9.4 ± 1.2 h while the average EE was 268.8 ± 54.8 kcal·h, which corresponded to about 40% of VOmeasured during IET. A mean distance ...
Frontiers in microbiology, 2017
Persister cells (PCs) are a subset of dormant, phenotypic variants of regular bacteria, highly to... more Persister cells (PCs) are a subset of dormant, phenotypic variants of regular bacteria, highly tolerant to antibiotics. Generation of PCs in vivo may account for the recalcitrance of most chronic infections to antimicrobial treatment and demands for the identification of new antimicrobial agents able to target such cells. The present study explored the possibility to obtain in vitro PCs of Pseudomonas aeruginosa and Staphylococcus aureus at high efficiency through chemical treatment, and to test their susceptibility to structurally different antimicrobial peptides (AMPs) and two clinically used peptide-based antibiotics, colistin and daptomycin. The main mechanism of action of these molecules (i.e., membrane-perturbing activity) renders them potential candidates to act against dormant cells. Exposure of stationary-phase cultures to optimized concentrations of the uncoupling agent cyanide m-chlorophenylhydrazone (CCCP) was able to generate at high efficiency PCs exhibiting an antibio...
International Journal of Molecular Sciences, 2017
Pseudomonas aeruginosa is a major cause of chronic lung infections in cystic fibrosis (CF) patien... more Pseudomonas aeruginosa is a major cause of chronic lung infections in cystic fibrosis (CF) patients. The ability of the bacterium to form biofilms and the presence of a thick and stagnant mucus in the airways of CF patients largely contribute to antibiotic therapy failure and demand for new antimicrobial agents able to act in the CF environment. The present study investigated the anti-P. aeruginosa activity of lin-SB056-1, a recently described semi-synthetic antimicrobial peptide, used alone and in combination with the cation chelator ethylenediaminetetraacetic acid (EDTA). Bactericidal assays were carried out in standard culture conditions and in an artificial sputum medium (ASM) closely resembling the CF environment. Peptide's structure and interaction with large unilamellar vesicles in media with different ionic strengths were also investigated through infrared spectroscopy. Lin-SB056-1 demonstrated fast and strong bactericidal activity against both mucoid and non-mucoid strains of P. aeruginosa in planktonic form and, in combination with EDTA, caused significant reduction of the biomass of P. aeruginosa mature biofilms. In ASM, the peptide/EDTA combination exerted a strong bactericidal effect and inhibited the formation of biofilm-like structures of P. aeruginosa. Overall, the results obtained highlight the potential of the lin-SB056-1/EDTA combination for the treatment of P. aeruginosa lung infections in CF patients.
International Journal of Molecular Sciences, 2017
Microbial resistance to conventional antibiotics is one of the most outstanding medical and scien... more Microbial resistance to conventional antibiotics is one of the most outstanding medical and scientific challenges of our times. Despite the recognised need for new anti-infective agents, however, very few new drugs have been brought to the market and to the clinic in the last three decades. This review highlights the properties of a new class of antibiotics, namely dendrimeric peptides. These intriguing novel compounds, generally made of multiple peptidic sequences linked to an inner branched core, display an array of antibacterial, antiviral and antifungal activities, usually coupled to low haemolytic activity. In addition, several peptides synthesized in oligobranched form proved to be promising tools for the selective treatment of cancer cells.
IMA fungus, 2016
We describe the morpho-anatomical features of the ectomycorrhizas (ECMs) formed by Lactifluus rug... more We describe the morpho-anatomical features of the ectomycorrhizas (ECMs) formed by Lactifluus rugatus on Cistus, a genus of about 20 species of woody shrubs typical of the Mediterranean maquis. The description of L. rugatus mycorrhizas on Cistus is the first ECM description of a species belonging to Lactifluus subgen. Pseudogymnocarpi. The ECM identity was verified through molecular tools. Anatomically, the characteristic of L. rugatus mycorrhiza is the presence of abundant, long "bottle-shaped" cystidia on mantle surface. Indeed, the overwhelming majority of milkcap mycorrhizas are acystidiate. This is the third Lactarius/Lactifluus mycorrhiza to have been described associated with Cistus, the others being Lactarius cistophilus and L. tesquorum. The phylogenetic distance between all these taxa is reflected by the diversity of the principal features of their ECMs, which share host-depending ECM features known for Cistus, but are otherwise distinguishable on the host roots....
PLOS ONE, 2017
The aim of this study was to determine the energy expenditure of a group of cavers of both gender... more The aim of this study was to determine the energy expenditure of a group of cavers of both genders and different ages and experience during a 10 hour subterranean exploration, using portable metabolimeters. The impact of caving activity on body composition and hydration were also assessed through bioelectrical impedance, and nutritional habits of cavers surveyed. During cave activity, measured total energy expenditure (TEE) was in the range 225-287 kcal/h for women-men (MET = 4.1), respectively; subjects had an energy intake from food in the range 1000-1200 kcal, thus inadequate to restore lost calories. Bayesian statistical analysis estimated the effect of predictive variables on TEE, revealing that experienced subjects had a 5% lower TEE than the less skilled ones and that women required a comparatively larger energy expenditure than men to perform the same task. BIVA (bioelectrical impedance vector analysis) showed that subjects were within the range of normal hydration before and after cave activity, but bioelectrical changes indicated a reduction of extracellular water in men, which might result in hypo-osmolal dehydration in the case of prolonged underground exercise. All these facts should be considered when planning cave explorations, preparing training programs for subjects practising caving, and optimizing a diet for cavers. Further, information gathered through this study could be of value to reduce accidents in caves related to increase in fatigue.
Ectomycorrhizae small, measuring up to 1.7 mm in length, pale yellow, with a smooth surface; when... more Ectomycorrhizae small, measuring up to 1.7 mm in length, pale yellow, with a smooth surface; when injured, whÍtish latex may be exuded. Emanating hyphae and rhizomorphs were not observed. The outer mantle is pseudoparenchymatous and formed by epidermoid hyphal cells. The middle mantle is densely plectenchymatous and mainly formed by a coarse net of worm-like and frequently ramified laticifers with granular contents. The inner mantle is densely plectenchymatous and heterogeneous in structure.
Amino Acids, 2015
Peptide-based antibiotics might help containing the rising tide of antimicrobial resistance. We d... more Peptide-based antibiotics might help containing the rising tide of antimicrobial resistance. We developed SB056, a semi-synthetic peptide with a dimeric dendrimer scaffold, active against both Gram-negative and Gram-positive bacteria. Being the mechanism of SB056 attributed to disruption of bacterial membranes, we enhanced the amphiphilic profile of the original, empirically derived sequence [WKKIRVRLSA-NH2] by interchanging the first two residues [KWKIRVRLSA-NH2], and explored the effects of this modification on the interaction of peptide, both in linear and dimeric forms, with model membranes and on antimicrobial activity. Results obtained against Escherichia coli and Staphylococcus aureus planktonic strains, with or without salts at physiological concentrations, confirmed the added value of dendrimeric structure over the linear one, especially at physiological ionic strength, and the impact of the higher amphipathicity obtained through sequence modification on enhancing peptide performances. SB056 peptides also displayed intriguing antibiofilm properties. Staphylococcus epidermidis was the most susceptible strain in sessile form, notably to optimized linear analog lin-SB056-1 and the wild-type dendrimer den-SB056. Membrane affinity of all peptides increased with the percentage of negatively charged lipids and was less influenced by the presence of salt in the case of dendrimeric peptides. The analog lin-SB056-1 displayed the highest overall affinity, even for zwitterionic PC bilayers. Thus, in addition to electrostatics, distribution of charged/polar and hydrophobic residues along the sequence might have a significant role in driving peptide-lipid interaction. Supporting this view, dendrimeric analog den-SB056-1 retained greater membrane affinity in the presence of salt than den-SB056, despite the fact that they bear exactly the same net positive charge.
ABSTRACT Some substituteda anthraquinones and anthrones were tested as regards their action on la... more ABSTRACT Some substituteda anthraquinones and anthrones were tested as regards their action on laccase excretion by Pleurotus sajor caju. Electrophoretic anaìysis showed that different isozymes were produced by the fungus in the presence of different compounds. Also other modifications into the culture media were studied, such as tlte degradation of anthraquinones and anthrones as a function of the time.
Peptides, 2014
Hymenochirin-1Pa (LKLSPKTKDTLKKVLKGAIKGAIAIASMA-NH 2) is a host-defense peptide first isolated fr... more Hymenochirin-1Pa (LKLSPKTKDTLKKVLKGAIKGAIAIASMA-NH 2) is a host-defense peptide first isolated from skin secretions of the frog Pseudhymenochirus merlini (Pipidae). A nuclear magnetic resonance structural investigation demonstrates that the peptide has a random coil conformation in water but, in the membrane-mimetic solvent 50% (v/v) trifluoroethanol-water adopts a well-defined conformation characterized by two ␣-helical domains from residues K6 to G17 and from G21 to M28, with the N-terminal region unfolded. The presence of a GXXXG domain, the most common structural motif found at the interface between interacting trans-membrane helices, between residues 17 and 21, introduces a kink corresponding to a deviation from linearity of 93 ± 31 •. Hymenochirin-1Pa shows broad spectrum antibacterial activity, including high potency against multidrug-resistant clinical isolates of Staphylococcus aureus, Acinetobacter baumannii, and Stenotrophomonas maltophilia. The peptide also shows high cytotoxic potency against human non-small lung adenocarcinoma A549 cells, breast adenocarcinoma MDA-MB-231 cells, and colorectal adenocarcinoma HT-29 cells but its therapeutic potential as an anti-cancer agent is limited by moderate hemolytic activity against human erythrocytes and lack of selectivity for tumor cells. Increasing cationicity of the peptide by substituting the Asp 9 residue by either l-Lys (K) or d-Lys (k) has relatively minor effects on antimicrobial and anti-tumor potencies but the [D9k] analog is non-hemolytic LC 50 > 400 M. Thus, [D9k]hymenochirin-1Pa may serve as a template for the design of non-toxic antimicrobial agents for use against multidrug-resistant pathogenic bacteria.
PLOS ONE, 2015
SB056 is a novel semi-synthetic antimicrobial peptide with a dimeric dendrimer scaffold. Active a... more SB056 is a novel semi-synthetic antimicrobial peptide with a dimeric dendrimer scaffold. Active against both Gram-negative and-positive bacteria, its mechanism has been attributed to a disruption of bacterial membranes. The branched peptide was shown to assume a βstranded conformation in a lipidic environment. Here, we report on a rational modification of the original, empirically derived linear peptide sequence [WKKIRVRLSA-NH 2 , SB056-lin]. We interchanged the first two residues [KWKIRVRLSA-NH 2 , β-SB056-lin] to enhance the amphipathic profile, in the hope that a more regular β-strand would lead to a better antimicrobial performance. MIC values confirmed that an enhanced amphiphilic profile indeed significantly increases activity against both Gram-positive and-negative strains. The membrane binding affinity of both peptides, measured by tryptophan fluorescence, increased with an increasing ratio of negatively charged/zwitterionic lipids. Remarkably, β-SB056-lin showed considerable binding even to purely zwitterionic membranes, unlike the original sequence, indicating that besides electrostatic attraction also the amphipathicity of the peptide structure plays a fundamental role in binding, by stabilizing the bound state. Synchrotron radiation circular dichroism and solid-state 19 F-NMR were used to characterize and compare the conformation and mobility of the membrane bound peptides. Both SB056lin and β-SB056-lin adopt a β-stranded conformation upon binding POPC vesicles, but the former maintains an intrinsic structural disorder that also affects its aggregation tendency. Upon introducing some anionic POPG into the POPC matrix, the sequence-optimized β-SB056-lin forms well-ordered β-strands once electro-neutrality is approached, and it aggregates into more extended β-sheets as the concentration of anionic lipids in the bilayer is raised. The enhanced antimicrobial activity of the analogue correlates with the formation of these extended β-sheets, which also leads to a dramatic alteration of membrane integrity as PLOS ONE |
Journal of natural products, Jan 26, 2014
Antimicrobial peptides (AMPs) are effectors of the innate immunity of most organisms. Their role ... more Antimicrobial peptides (AMPs) are effectors of the innate immunity of most organisms. Their role in the defense against pathogen attack and their high selectivity for bacterial cells make them attractive for the development of a new class of antimicrobial drugs. The N-terminal fragment of the frog-skin peptide esculentin-1b (Esc(1-18)) has shown broad-spectrum antimicrobial activity. Similarly to most cationic AMPs, it is supposed to act by binding to and damaging the negatively charged plasma membrane of bacteria. Differently from many other AMPs, Esc(1-18) activity is preserved in biological fluids such as serum. In this work, a structural investigation was performed through NMR spectroscopy. The 3D structure was obtained in the presence of either zwitterionic or negatively charged micelles as membrane models for eukaryotic and prokaryotic membranes, respectively. Esc(1-18) showed a higher affinity for and deeper insertion into the latter and adopted an amphipathic helical structu...
Mycologia, 2000
To date, the ectomycorrhizae formed by silver fir (Abies alba), an ecologically valuable and indi... more To date, the ectomycorrhizae formed by silver fir (Abies alba), an ecologically valuable and indigenous tree species in many European mountain forests, have been poorly investigated. We characterized the mycorrhizae formed by three Lactarius species (Lac. subsericatus, Lac. intermedius, Lac. salmonicolor) on silver fir, on the basis of material originating from central Italy. The identification of the fungal symbiont was achieved by means of morphoanatomical observations of mycorrhizae, and by comparison of ITS sequences obtained from mycorrhizae and sporocarps of putative fungal partners. Sequences also were obtained from specimens of the same species but from different geographic origin or from closely related Lactarius species. A maximum likelihood analysis of the data was performed. On the whole, the resultant tree is in good agreement with sporocarp and mycorrhiza morphology. RFLP patterns were calculated from sequence data. A discussion on the main morphoanatomical characters distinguishing the Lactarius ectomycorrhizae reported in this study from those already described belonging to related species, is also included. The accuracy of different methods to identify mycorrhizae formed by closely related Lactarius species on silver fir, are discussed.
Mycologia, 2004
Lactarius is one of the larger genera of ectomycorrhizal Basidiomycota, with about 400 species re... more Lactarius is one of the larger genera of ectomycorrhizal Basidiomycota, with about 400 species recognized worldwide. The ectomycorrhizae formed by Lactarius tesquorum on Cistus sp., one of the most common and ecologically relevant shrubs in the semi-arid regions in the Mediterranean basin, are described here in terms of morphological, anatomical and molecular features. An ITS rDNA sequence-based phylogenetic analysis was performed on the related European Lactarius taxa (L. mairei, L. pubescens, L. scoticus, L. spinosulus, L. torminosulus and L. torminosus) currently classified together with L. tesquorum in the subgenus Piperites section Piperites. Piperites s.s. could be divided into two main clusters; L. mairei and especially L. spinosulus were related less closely to the other taxa. This study is part of a broader effort to extend our knowledge of the distribution, phylogeny and ectomycorrhizal biology of Lactarius species in selected ecosystems.
Uploads
Papers by Andrea C. Rinaldi