Publications by authors named "Teresa Rinaldi"

28 Publications

  • Page 1 of 1

The Mentalized Affectivity Scale (MAS): Development and validation of the Italian version.

PLoS One 2021 5;16(4):e0249272. Epub 2021 Apr 5.

Research Unit on Theory of Mind, Department of Psychology, Università Cattolica del Sacro Cuore, Milan, Italy.

This study proposes a psychometric validation of the Italian version of the Mentalized Affectivity Scale (MAS) developed by Greenberg and colleagues in 2017. The mentalized affectivity construct integrates mentalization ability in the process of emotional regulation. An adult sample (N = 506) completed the 60-items MAS online version. In contrast to the three-factor structure of the original version, the Italian context confirmatory and exploratory factor analyses with splitted sample (CFA = 258; EFA = 248) revealed a five-factor structure. The hierarchically structured MAS factors are: Emotional Processing (being able to process emotion in situations); Expressing Emotions (talking and knowing emotions); Identifying Emotions (awareness of emotions); Control Processing (to control emotional reactions and expression), and Autobiographical Memory (related to childhood experiences). We also verified the convergent validity and reliability of the Italian version of the MAS by correlating the above five factors with measures of emotion regulation and reflective functioning. Moreover, we analyzed the relationships among the factors of the MAS, personality measures and well-being indexes, such as life satisfaction and self-efficacy: The new 35-item MAS scale showed robust correlations with all the tested constructs. Our results confirm that the MAS is a useful measure to assess mentalized affectivity, with the Italian version showing a more complex structure than the original English one, thus enriching the literature about mentalization.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249272PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021192PMC
April 2021

Astrobiology of life on Earth.

Environ Microbiol 2021 Apr 5. Epub 2021 Apr 5.

School of Biological Sciences, Department of Microbiology, Southern Illinois University, Carbondale, IL, 62901, USA.

Astrobiology is mistakenly regarded by some as a field confined to studies of life beyond Earth. Here, we consider life on Earth through an astrobiological lens. Whereas classical studies of microbiology historically focused on various anthropocentric sub-fields (such as fermented foods or commensals and pathogens of crop plants, livestock and humans), addressing key biological questions via astrobiological approaches can further our understanding of all life on Earth. We highlight potential implications of this approach through the articles in this Environmental Microbiology special issue 'Ecophysiology of Extremophiles'. They report on the microbiology of places/processes including low-temperature environments and chemically diverse saline- and hypersaline habitats; aspects of sulphur metabolism in hypersaline lakes, dysoxic marine waters, and thermal acidic springs; biology of extremophile viruses; the survival of terrestrial extremophiles on the surface of Mars; biological soils crusts and rock-associated microbes of deserts; subsurface and deep biosphere, including a salticle formed within Triassic halite; and interactions of microbes with igneous and sedimentary rocks. These studies, some of which we highlight here, contribute to our understanding of the spatiotemporal reach of Earth'sfunctional biosphere, and the tenacity of terrestrial life. Their findings will help set the stage for future work focused on the constraints for life, and how organisms adapt and evolve to circumvent these constraints.
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http://dx.doi.org/10.1111/1462-2920.15499DOI Listing
April 2021

Active microbial ecosystem in Iron-Age tombs of the Etruscan civilization.

Environ Microbiol 2020 Nov 16. Epub 2020 Nov 16.

Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy.

Earth's microbial biosphere extends down through the crust and much of the subsurface, including those microbial ecosystems located within cave systems. Here, we elucidate the microbial ecosystems within anthropogenic 'caves'; the Iron-Age, subterranean tombs of central Italy. The interior walls of the rock (calcium-rich macco) were painted ~2500 years ago and are covered with CaCO needles (known as moonmilk). The aims of the current study were to: identify biological/geochemical/biophysical determinants of and characterize bacterial communities involved in CaCO precipitation; challenge the maxim that biogenic activity necessarily degrades surfaces; locate the bacterial cells that are the source of the CaCO precipitate; and gain insight into the kinetics of moonmilk formation. We reveal that this environment hosts communities that consist primarily of bacteria that are mesophilic for temperature and xerotolerance (including Actinobacteria, Bacteroidetes and Proteobacteria); is populated by photosynthetic Cyanobacteria exhibiting heterotrophic nutrition (Calothrix and Chroococcidiopsis); and has CaCO precipitating on the rock surfaces (confirmation that this process is biogenic) that acts to preserve rather than damage the painted surface. We also identified that some community members are psychrotolerant (Polaromonas), acidotolerant or acidophilic (members of the Acidobacteria), or resistant to ionizing radiation (Brevundimonas and Truepera); elucidate the ways in which microbiology impacts mineralogy and vice versa; and reveal that biogenic formation of moonmilk can occur rapidly, that is, over a period of 10 to 56 years. We discuss the paradox that these ecosystems, that are for the most part in the dark and lack primary production, are apparently highly active, biodiverse and biomass-rich.
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http://dx.doi.org/10.1111/1462-2920.15327DOI Listing
November 2020

The central role of gut microbiota in drug metabolism and personalized medicine.

Future Med Chem 2020 07 29;12(13):1197-1200. Epub 2020 May 29.

Department of Biology & Biotechnology, Sapienza University of Rome, 00185, Rome, Italy.

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http://dx.doi.org/10.4155/fmc-2020-0023DOI Listing
July 2020

Artemisinin Derivatives with Antimelanoma Activity Show Inhibitory Effect against Human DNA Topoisomerase 1.

ACS Med Chem Lett 2020 May 10;11(5):1035-1040. Epub 2020 Apr 10.

Dipartimento di Biologia, Università di Padova Distaccato presso il "Centro Linceo Beniamino Segre" Accademia Nazionale dei Lincei, Palazzo Corsini, Via della Lungara 10, 00165 Rome, Italy.

Artesunic acid and artemisinin are natural substances with promiscuous anticancer activity against different types of cancer cell lines. The mechanism of action of these compounds is associated with the formation of reactive radical species by cleavage of the sesquiterpene pharmacophore endoperoxide bridge. Here we suggested topoisomerase 1 as a possible molecular target for the improvement of the anticancer activity of these compounds. In this context, we report that novel hybrid and dimer derivatives of artesunic acid and artemisinin, bearing camptothecin and SN38 as side-chain biological effectors, can inhibit growth of yeast cells overexpressing human topoisomerase 1 and its enzymatic activity . These derivatives showed also anticancer activity in melanoma cell lines higher than camptothecin and paclitaxel. molecular docking calculations highlighted a common binding mode for the novel derivatives, with the sesquiterpene lactone scaffold being located near the traditional recognition site for camptothecin, while the bioactive side-chain effector laid in the camptothecin cleft.
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http://dx.doi.org/10.1021/acsmedchemlett.0c00131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7236541PMC
May 2020

The COP9 signalosome mediates the Spt23 regulated fatty acid desaturation and ergosterol biosynthesis.

FASEB J 2020 04 19;34(4):4870-4889. Epub 2020 Feb 19.

Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Israel.

The COP9 signalosome (CSN) is a conserved eukaryotic complex, essential for vitality in all multicellular organisms and critical for the turnover of key cellular proteins through catalytic and non-catalytic activities. Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of the CSN complex, since it includes a conserved enzymatic core but lacks non-catalytic activities, probably explaining its non-essentiality for life. A previous transcriptomic analysis of an S. cerevisiae strain deleted in the CSN5/RRI1 gene, encoding to the CSN catalytic subunit, revealed a downregulation of genes involved in lipid metabolism. We now show that the S. cerevisiae CSN holocomplex is essential for cellular lipid homeostasis. Defects in CSN assembly or activity lead to decreased quantities of ergosterol and unsaturated fatty acids (UFA); vacuole defects; diminished lipid droplets (LDs) size; and to accumulation of endoplasmic reticulum (ER) stress. The molecular mechanism behind these findings depends on CSN involvement in upregulating mRNA expression of SPT23. Spt23 is a novel activator of lipid desaturation and ergosterol biosynthesis. Our data reveal for the first time a functional link between the CSN holocomplex and Spt23. Moreover, CSN-dependent upregulation of SPT23 transcription is necessary for the fine-tuning of lipid homeostasis and for cellular health.
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http://dx.doi.org/10.1096/fj.201902487RDOI Listing
April 2020

Statins interfere with the attachment of mtDNA to the inner mitochondrial membrane.

J Enzyme Inhib Med Chem 2020 Dec;35(1):129-137

Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy.

The 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme of the mevalonate pathway for the synthesis of cholesterol in mammals (ergosterol in fungi), is inhibited by statins, a class of cholesterol lowering drugs. Indeed, statins are in a wide medical use, yet statins treatment could induce side effects as hepatotoxicity and myopathy in patients. We used as a model to investigate the effects of statins on mitochondria. We demonstrate that statins are active in by lowering the ergosterol content in cells and interfering with the attachment of mitochondrial DNA to the inner mitochondrial membrane. Experiments on murine myoblasts confirmed these results in mammals. We propose that the instability of mitochondrial DNA is an early indirect target of statins.
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http://dx.doi.org/10.1080/14756366.2019.1687461DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6844431PMC
December 2020

The Proteasome Lid Triggers COP9 Signalosome Activity during the Transition of Cells into Quiescence.

Biomolecules 2019 09 4;9(9). Epub 2019 Sep 4.

Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa at Oranim, Tivon 36006, Israel.

The class of Cullin-RING E3 ligases (CRLs) selectively ubiquitinate a large portion of proteins targeted for proteolysis by the 26S proteasome. Before degradation, ubiquitin molecules are removed from their conjugated proteins by deubiquitinating enzymes, a handful of which are associated with the proteasome. The CRL activity is triggered by modification of the Cullin subunit with the ubiquitin-like protein, NEDD8 (also known as Rub1 in ). Cullin modification is then reversed by hydrolytic action of the COP9 signalosome (CSN). As the NEDD8-Rub1 catalytic cycle is not essential for the viability of , this organism is a useful model system to study the alteration of Rub1-CRL conjugation patterns. In this study, we describe two distinct mutants of Rpn11, a proteasome-associated deubiquitinating enzyme, both of which exhibit a biochemical phenotype characterized by high accumulation of Rub1-modified Cdc53-Cullin1 (yCul1) upon entry into quiescence in . Further characterization revealed proteasome 19S-lid-associated deubiquitination activity that authorizes the hydrolysis of Rub1 from yCul1 by the CSN complex. Thus, our results suggest a negative feedback mechanism via proteasome capacity on upstream ubiquitinating enzymes.
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http://dx.doi.org/10.3390/biom9090449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770237PMC
September 2019

Use of organoids in medicinal chemistry: challenges on ethics and biosecurity.

Future Med Chem 2019 05;11(10):1087-1090

IBPM-CNR Institute of Molecular Biology & Pathology, Italian National Research Council, 00185, Rome, Italy.

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http://dx.doi.org/10.4155/fmc-2018-0341DOI Listing
May 2019

The hypoxic transcription factor KlMga2 mediates the response to oxidative stress and influences longevity in the yeast Kluyveromyces lactis.

FEMS Yeast Res 2019 05;19(3)

Department Biology and Biotechnology C. Darwin, University of Roma Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy.

Hypoxia is defined as the decline of oxygen availability, depending on environmental supply and cellular consumption rate. The decrease in O2 results in reduction of available energy in facultative aerobes. The response and/or adaptation to hypoxia and other changing environmental conditions can influence the properties and functions of membranes by modifying lipid composition. In the yeast Kluyveromyces lactis, the KlMga2 gene is a hypoxic regulatory factor for lipid biosynthesis-fatty acids and sterols-and is also involved in glucose signaling, glucose catabolism and is generally important for cellular fitness. In this work we show that, in addition to the above defects, the absence of the KlMGA2 gene caused increased resistance to oxidative stress and extended lifespan of the yeast, associated with increased expression levels of catalase and SOD genes. We propose that KlMga2 might also act as a mediator of the oxidative stress response/adaptation, thus revealing connections among hypoxia, glucose signaling, fatty acid biosynthesis and ROS metabolism in K. lactis.
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http://dx.doi.org/10.1093/femsyr/foz020DOI Listing
May 2019

Ergosterol reduction impairs mitochondrial DNA maintenance in S. cerevisiae.

Biochim Biophys Acta Mol Cell Biol Lipids 2019 03 12;1864(3):290-303. Epub 2018 Dec 12.

Department of Biology and Biotechnology "Charles Darwin", La Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.; Pasteur Institute-Cenci Bolognetti Foundation, Viale Regina Elena, 291, 00100 Rome, Italy.. Electronic address:

Sterols are essential lipids, involved in many biological processes. In Saccharomyces cerevisiae, the enzymes of the ergosterol biosynthetic pathway (Erg proteins) are localized in different cellular compartments. With the aim of studying organelle interactions, we discovered that Erg27p resides mainly in Lipid Droplets (LDs) in respiratory competent cells, while in absence of respiration, is found mostly in the ER. The results presented in this paper demonstrate an interplay between the mitochondrial respiration and ergosterol production: on the one hand, rho° cells show lower ergosterol content when compared with wild type respiratory competent cells, on the other hand, the ergosterol biosynthetic pathway influences the mitochondrial status, since treatment with ketoconazole, which blocks the ergosterol pathway, or the absence of the ERG27 gene, induced rho° production in S. cerevisiae. The loss of mitochondrial DNA in the ∆erg27 strain is fully suppressed by exogenous addition of ergosterol. These data suggest the notion that ergosterol is essential for maintaining the mitochondrial DNA attached to the inner mitochondrial membrane.
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http://dx.doi.org/10.1016/j.bbalip.2018.12.002DOI Listing
March 2019

Calcite moonmilk of microbial origin in the Etruscan Tomba degli Scudi in Tarquinia, Italy.

Sci Rep 2018 10 26;8(1):15839. Epub 2018 Oct 26.

La Sapienza University of Rome, Dept. of Biology and Biotechnology Charles Darwin, Rome, 00185, Italy.

A white deposit covering the walls in the Stanza degli Scudi of the Tomba degli Scudi, Tarquinia, Italy, has been investigated. In this chamber, which is still preserved from any kind of intervention such as cleaning and sanitization, ancient Etruscans painted shields to celebrate the military power of the Velcha family. Scanning electron microscopy analysis has revealed the presence of characteristic nanostructures corresponding to a calcite secondary mineral deposit called moonmilk. Analysis of the microbial community identified Proteobacteria, Acidobacteria and Actinobacteria as the most common phyla in strong association with the moonmilk needle fibre calcite and nanofibers of calcium carbonate. Employing classical microbiological analysis, we isolated from moonmilk a Streptomyces strain able to deposit gypsum and calcium carbonate on plates, supporting the hypothesis of an essential contribution of microorganisms to the formation of moonmilk.
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http://dx.doi.org/10.1038/s41598-018-34134-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203712PMC
October 2018

A role for microbial selection in frescoes' deterioration in Tomba degli Scudi in Tarquinia, Italy.

Sci Rep 2017 07 20;7(1):6027. Epub 2017 Jul 20.

La Sapienza University of Rome, Departement of Biology and Biotechnology "Charles Darwin", Piazzale Aldo Moro, 5, 00185, Rome, Italy.

Mural paintings in the hypogeal environment of the Tomba degli Scudi in Tarquinia, Italy, show a quite dramatic condition: the plaster mortar lost his cohesion and a white layer coating is spread over almost all the wall surfaces. The aim of this research is to verify if the activity of microorganisms could be one of the main causes of deterioration and if the adopted countermeasures (conventional biocide treatments) are sufficient to stop it. A biocide treatment of the whole environment has been carried out before the conservative intervention and the tomb has been closed for one month. When the tomb was opened again, we sampled the microorganisms present on the frescoes and we identified four Bacillus species and one mould survived to the biocide treatment. These organisms are able to produce spores, a highly resistant biological form, which has permitted the survival despite the biocide treatment. We show that these Bacillus strains are able to produce calcium carbonate and could be responsible for the white deposition that was damaging and covering the entire surface of the frescoes. Our results confirm that the sanitation intervention is non always resolutive and could even be deleterious in selecting harmful microbial communities.
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http://dx.doi.org/10.1038/s41598-017-06169-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5519700PMC
July 2017

Biological Dual-Use Research and Synthetic Biology of Yeast.

Sci Eng Ethics 2017 04 20;23(2):365-374. Epub 2016 Jun 20.

Department of Biology and Biotechnology, La Sapienza University of Rome, Rome, Italy.

In recent years, the publication of the studies on the transmissibility in mammals of the H5N1 influenza virus and synthetic genomes has triggered heated and concerned debate within the community of scientists on biological dual-use research; these papers have raised the awareness that, in some cases, fundamental research could be directed to harmful experiments, with the purpose of developing a weapon that could be used by a bioterrorist. Here is presented an overview regarding the dual-use concept and its related international agreements which underlines the work of the Australia Group (AG) Export Control Regime. It is hoped that the principles and activities of the AG, that focuses on export control of chemical and biological dual-use materials, will spread and become well known to academic researchers in different countries, as they exchange biological materials (i.e. plasmids, strains, antibodies, nucleic acids) and scientific papers. To this extent, and with the aim of drawing the attention of the scientific community that works with yeast to the so called Dual-Use Research of Concern, this article reports case studies on biological dual-use research and discusses a synthetic biology applied to the yeast Saccharomyces cerevisiae, namely the construction of the first eukaryotic synthetic chromosome of yeast and the use of yeast cells as a factory to produce opiates. Since this organism is considered harmless and is not included in any list of biological agents, yeast researchers should take simple actions in the future to avoid the sharing of strains and advanced technology with suspicious individuals.
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http://dx.doi.org/10.1007/s11948-016-9774-1DOI Listing
April 2017

Functional roles of the fatty acid desaturases encoded by KlOLE1, FAD2 and FAD3 in the yeast Kluyveromyces lactis.

Microbiology (Reading) 2016 08 27;162(8):1435-1445. Epub 2016 May 27.

Department of Biology and Biotechnology C. Darwin, Sapienza Università di Roma, p.le Aldo Moro 5, 00185, Roma, Italy.

Functional properties of cell membranes depend on their composition, particularly on the relative amount of saturated, unsaturated and polyunsaturated fatty acids present in the phospholipids. The aim of this study was to investigate the effect of cell membrane composition on cell fitness, adaptation and stress response in Kluyveromyces lactis. To this purpose, we have deleted the genes FAD2 and FAD3 encoding Δ12 and ω3 desaturases in Kluyveromyces lactis, thus generating mutant strains with altered fatty acid composition of membranes. These strains were viable and able to grow in stressing conditions like hypoxia and low temperature. Deletion of the Δ9 desaturase-encoding gene KlOLE1 resulted in lethality, suggesting that this enzyme has an essential role in this yeast. Transcription of the desaturase genes KlOLE1, FAD2 and FAD3 and cellular localization of the corresponding enzymes, have been studied under hypoxia and cold stress. Our findings indicate that expression of these desaturase genes and membrane composition were modulated by hypoxia and temperature stress, although the changes induced by these and other assayed conditions did not dramatically affect the general cellular fitness.
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http://dx.doi.org/10.1099/mic.0.000315DOI Listing
August 2016

Yeast as a tool to select inhibitors of the cullin deneddylating enzyme Csn5.

J Enzyme Inhib Med Chem 2016 Dec 30;31(6):1632-7. Epub 2016 Mar 30.

a Istituto Pasteur Fondazione Cenci Bolognetti, Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy .

The CSN complex plays a key role in various cellular pathways: through a metalloprotease activity of its Csn5 deneddylating enzyme, it regulates the activity of Cullin-RING ligases (CRLs). Indeed, Csn5 has been found amplified in many tumors, but, due to its pleiotropic effects, it is difficult to dissect its function and the involvement in cancer progression. Moreover, while growing evidences point to the neddylation function as a good target for drug development; specific inhibitors have not yet been developed for the CSN. Here, we propose the yeast Saccharomyces cerevisiae as a model system to screen libraries of small molecules as inhibitors of cullins deneddylation, taking advantage of the unique feature of this organism to survive without a functional CSN5 gene and to accumulate a fully neddylated cullin substrate. By combining molecular modeling and simple genetic tools, we were able to identify two small molecular fragments as selective inhibitors of Csn5 deneddylation function.
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http://dx.doi.org/10.3109/14756366.2016.1160901DOI Listing
December 2016

"Poppy" yeast.

Authors:
Teresa Rinaldi

EMBO Rep 2015 Nov 28;16(11):1410. Epub 2015 Sep 28.

Department of Biology and Biotechnology "Charles Darwin", La Sapienza University of Rome and Reserve Major of the Italian Army.

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http://dx.doi.org/10.15252/embr.201541367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4641490PMC
November 2015

Unsaturated fatty acids-dependent linkage between respiration and fermentation revealed by deletion of hypoxic regulatory KlMGA2 gene in the facultative anaerobe-respiratory yeast Kluyveromyces lactis.

FEMS Yeast Res 2015 Aug 27;15(5):fov028. Epub 2015 May 27.

Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, p.le Aldo Moro 5, 00185 Rome, Italy

In the yeast Kluyveromyces lactis, the inactivation of structural or regulatory glycolytic and fermentative genes generates obligate respiratory mutants which can be characterized by sensitivity to the mitochondrial drug antimycin A on glucose medium (Rag(-) phenotype). Rag(-) mutations can occasionally be generated by the inactivation of genes not evidently related to glycolysis or fermentation. One such gene is the hypoxic regulatory gene KlMGA2. In this work, we report a study of the many defects, in addition to the Rag(-) phenotype, generated by KlMGA2 deletion. We analyzed the fermentative and respiratory metabolism, mitochondrial functioning and morphology in the Klmga2Δ strain. We also examined alterations in the regulation of the expression of lipid biosynthetic genes, in particular fatty acids, ergosterol and cardiolipin, under hypoxic and cold stress and the phenotypic suppression by unsaturated fatty acids of the deleted strain. Results indicate that, despite the fact that the deleted mutant strain had a typical glycolytic/fermentative phenotype and KlMGA2 is a hypoxic regulatory gene, the deletion of this gene generated defects linked to mitochondrial functions suggesting new roles of this protein in the general regulation and cellular fitness of K. lactis. Supplementation of unsaturated fatty acids suppressed or modified these defects suggesting that KlMga2 modulates membrane functioning or membrane-associated functions, both cytoplasmic and mitochondrial.
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http://dx.doi.org/10.1093/femsyr/fov028DOI Listing
August 2015

The human SLC25A33 and SLC25A36 genes of solute carrier family 25 encode two mitochondrial pyrimidine nucleotide transporters.

J Biol Chem 2014 Nov 15;289(48):33137-48. Epub 2014 Oct 15.

From the Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, via Orabona 4, 70125 Bari, Italy, Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy

The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport inorganic anions, amino acids, carboxylates, nucleotides, and coenzymes across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. Here two members of this family, SLC25A33 and SLC25A36, have been thoroughly characterized biochemically. These proteins were overexpressed in bacteria and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that SLC25A33 transports uracil, thymine, and cytosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism and SLC25A36 cytosine and uracil (deoxy)nucleoside mono-, di-, and triphosphates by uniport and antiport. Both carriers also transported guanine but not adenine (deoxy)nucleotides. Transport catalyzed by both carriers was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. In confirmation of their identity (i) SLC25A33 and SLC25A36 were found to be targeted to mitochondria and (ii) the phenotypes of Saccharomyces cerevisiae cells lacking RIM2, the gene encoding the well characterized yeast mitochondrial pyrimidine nucleotide carrier, were overcome by expressing SLC25A33 or SLC25A36 in these cells. The main physiological role of SLC25A33 and SLC25A36 is to import/export pyrimidine nucleotides into and from mitochondria, i.e. to accomplish transport steps essential for mitochondrial DNA and RNA synthesis and breakdown.
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http://dx.doi.org/10.1074/jbc.M114.610808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4246075PMC
November 2014

Getting lipids from glycerol: new perspectives on biotechnological exploitation of Candida freyschussii.

Microb Cell Fact 2014 Jun 7;13:83. Epub 2014 Jun 7.

Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 183, 41100 Modena, Italy.

Background: Microbial lipids represent a valuable alternative feedstock for biodiesel production when oleaginous microbes are cultured with inexpensive substrates in processes exhibiting high yield and productivity. In this perspective, crude glycerol is among the most promising raw materials for lipid production, because it is the costless residual of biodiesel production. Thus, cultivation of oleaginous yeasts in glycerol-based media is attracting great interest and natural biodiversity is increasingly explored to identify novel oleaginous species recycling this carbon source for growth and lipid production.

Results: Thirty-three yeasts strains belonging to 19 species were screened for the ability to grow and produce intracellular lipids in a pure glycerol-based medium with high C/N ratio. A minority of them consumed most of the glycerol and generated visible lipid bodies. Among them, Candida freyschussii ATCC 18737 was selected, because it exhibited the highest lipid production and glycerol conversion yield. Lipid production in this strain was positively affected by the increase of C/N ratio, but growth was inhibited by glycerol concentration higher than 40 g/L. In batch cultures, the highest lipid production (4.6 g/L), lipid content of biomass (33% w/w), and lipid volumetric productivity (0.15 g/L/h) were obtained with 40 g/L glycerol, during the course of a 30-h process. Fed-batch cultivation succeeded in preventing substrate inhibition and in achieving a high cell-density culture. The improved lipid production and volumetric productivity reached the remarkable high level of 28 g/L and 0.28 g/L/h, respectively. The lipids accumulated by C. freyschussii ATCC 18737 have similar fatty acid composition of plant oil indicating their potential use as biodiesel feedstock. Calculated physicochemical properties of a biodiesel produced with the lipids from C. freyschussii ATCC 18737 are expected to meet the European and American standards, being equal to those of rapeseed and palm biodiesel.

Conclusions: C. freyschussii ATCC 18737 could be considered an interesting microorganism for utilization in biofuel industry. Cultivation of this yeast in media containing crude glycerol should be investigated deeper in order to evaluate whether it may find application in the valorization of the waste of biodiesel manufacturing.
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http://dx.doi.org/10.1186/1475-2859-13-83DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4064286PMC
June 2014

Reversible 26S proteasome disassembly upon mitochondrial stress.

Cell Rep 2014 Jun 22;7(5):1371-1380. Epub 2014 May 22.

Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel. Electronic address:

In eukaryotic cells, proteasomes exist primarily as 26S holoenzymes, the most efficient configuration for ubiquitinated protein degradation. Here, we show that acute oxidative stress caused by environmental insults or mitochondrial defects results in rapid disassembly of 26S proteasomes into intact 20S core and 19S regulatory particles. Consequently, polyubiquitinated substrates accumulate, mitochondrial networks fragment, and cellular reactive oxygen species (ROS) levels increase. Oxidation of cysteine residues is sufficient to induce proteasome disassembly, and spontaneous reassembly from existing components is observed both in vivo and in vitro upon reduction. Ubiquitin-dependent substrate turnover also resumes after treatment with antioxidants. Reversible attenuation of 26S proteasome activity induced by acute mitochondrial or oxidative stress may be a short-term response distinct from adaptation to long-term ROS exposure or changes during aging.
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http://dx.doi.org/10.1016/j.celrep.2014.04.030DOI Listing
June 2014

An high-throughput in vivo screening system to select H3K4-specific histone demethylase inhibitors.

PLoS One 2014 29;9(1):e86002. Epub 2014 Jan 29.

Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy.

Background: Histone demethylases (HDMs) have a prominent role in epigenetic regulation and are emerging as potential therapeutic cancer targets. The search for small molecules able to inhibit HDMs in vivo is very active but at the present few compounds were found to be specific for defined classes of these enzymes.

Methodology/principal Findings: In order to discover inhibitors specific for H3K4 histone demethylation we set up a screening system which tests the effects of candidate small molecule inhibitors on a S.cerevisiae strain which requires Jhd2 demethylase activity to efficiently grow in the presence of rapamycin. In order to validate the system we screened a library of 45 structurally different compounds designed as competitive inhibitors of α -ketoglutarate (α-KG) cofactor of the enzyme, and found that one of them inhibited Jhd2 activity in vitro and in vivo. The same compound effectively inhibits human Jumonji AT-Rich Interactive Domain (JARID) 1B and 1D in vitro and increases H3K4 tri-methylation in HeLa cell nuclear extracts (NEs). When added in vivo to HeLa cells, the compound leads to an increase of tri-methyl-H3K4 (H3K4me3) but does not affect H3K9 tri-methylation. We describe the cytostatic and toxic effects of the compound on HeLa cells at concentrations compatible with its inhibitory activity.

Conclusions/significance: Our screening system is proved to be very useful in testing putative H3K4-specific HDM inhibitors for the capacity of acting in vivo without significantly altering the activity of other important 2-oxoglutarate oxygenases.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0086002PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3906020PMC
September 2014

The COP9 signalosome is involved in the regulation of lipid metabolism and of transition metals uptake in Saccharomyces cerevisiae.

FEBS J 2014 Jan 25;281(1):175-90. Epub 2013 Nov 25.

Istituto Pasteur - Fondazione Cenci Bolognetti, Department of Biology and Biotechnology 'C. Darwin', Sapienza University of Rome, Italy.

The COP9 signalosome (CSN) is a highly conserved eukaryotic protein complex which regulates the cullin RING family of ubiquitin ligases and carries out a deneddylase activity that resides in subunit 5 (CSN5). Whereas CSN activity is essential for the development of higher eukaryotes, several unicellular fungi including the budding yeast Saccharomyces cerevisiae can survive without a functional CSN. Nevertheless, the budding yeast CSN is biochemically active and deletion mutants of each of its subunits exhibit deficiency in cullins deneddylation, although the biological context of this activity is still unknown in this organism. To further characterize CSN function in budding yeast, we present here a transcriptomic and proteomic analysis of a S. cerevisiae strain deleted in the CSN5/RRI1 gene (hereafter referred to as CSN5), coding for the only canonical subunit of the complex. We show that Csn5 is involved in modulation of the genes controlling amino acid and lipid metabolism and especially ergosterol biosynthesis. These alterations in gene expression correlate with the lower ergosterol levels and increased intracellular zinc content which we observed in csn5 null mutant cells. We show that some of these regulatory effects of Csn5, in particular the control of isoprenoid biosynthesis, are conserved through evolution, since similar transcriptomic and/or proteomic effects of csn5 mutation were previously observed in other eukaryotic organisms such as Aspergillus nidulans, Arabidopsis thaliana and Drosophila melanogaster. Our results suggest that the diverged budding yeast CSN is more conserved than was previously thought.
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http://dx.doi.org/10.1111/febs.12584DOI Listing
January 2014

Analysis of the rpn11-m1 proteasomal mutant reveals connection between cell cycle and mitochondrial biogenesis.

FEMS Yeast Res 2011 Feb 9;11(1):60-71. Epub 2010 Nov 9.

Department of Cell and Developmental Biology, Pasteur Institute-Cenci Bolognetti Foundation, University of Rome, Rome, Italy.

The proteasomal lid subunit Rpn11 is essential for maintaining a correct cell cycle and mitochondrial morphology in Saccharomyces cerevisiae. In this paper, we show that the rpn11-m1 mutant has a peculiar cell cycle defect reminiscent of mutants defective in the FEAR pathway that delay the release of the Cdc14 protein phosphatase from the nucleolus. We analyzed the rpn11-m1 phenotypes and found that overexpression of Cdc14 suppresses all the rpn11-m1 defects, including the mitochondrial ones. Suppression by Cdc14 of the rpn11-m1 mitochondrial morphology defect reveals an uncharacterized connection between mitochondrial and cell cycle events. Interestingly, the overexpression of Cdc14 also partially restores the tubular network in an Δmmm2 strain, which lacks a mitochondrial protein belonging to the complex necessary to anchor the mitochondrion to the actin cytoskeleton. Altogether our findings indicate, for the first time, a cross-talk between the cell cycle and mitochondrial morphology.
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http://dx.doi.org/10.1111/j.1567-1364.2010.00690.xDOI Listing
February 2011

Mitochondrial diseases and the role of the yeast models.

FEMS Yeast Res 2010 Dec 14;10(8):1006-22. Epub 2010 Oct 14.

Department of Cell and Developmental Biology, Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy.

Nowadays, mitochondrial diseases are recognized and studied with much attention and they cannot be considered anymore as 'rare diseases'. Yeast has been an instrumental organism to understand the genetic and molecular aspects of the many roles of mitochondria within the cells. Thanks to the general conservation of mitochondrial genes and pathways between human and yeast, it can also be used to model some diseases. In this review, we focus on the most recent topics, exemplifying those for which yeast models have been especially valuable.
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http://dx.doi.org/10.1111/j.1567-1364.2010.00685.xDOI Listing
December 2010

A nonproteolytic proteasome activity controls organelle fission in yeast.

J Cell Sci 2009 Oct 22;122(Pt 20):3673-83. Epub 2009 Sep 22.

University of Paris-Sud, CNRS, UMR 8621, Institute of Genetics and Microbiology, Orsay 91405, France.

To understand the processes underlying organelle function, dynamics and inheritance, it is necessary to identify and characterize the regulatory components involved. Recently in yeast and mammals, proteins of the membrane fission machinery (Dnm1-Mdv1-Caf4-Fis1 in yeast and DLP1-FIS1 in human) have been shown to have a dual localization on mitochondria and peroxisomes, where they control mitochondrial fission and peroxisome division. Here, we show that whereas vacuole fusion is regulated by the proteasome degradation function, mitochondrial fission and peroxisomal division are not controlled by the proteasome activity but rather depend on a new function of the proteasomal lid subunit Rpn11. Rpn11 was found to regulate the Fis1-dependent fission machinery of both organelles. These findings indicate a unique role of the Rpn11 protein in mitochondrial fission and peroxisomal proliferation that is independent of its role in proteasome-associated deubiquitylation.
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http://dx.doi.org/10.1242/jcs.050229DOI Listing
October 2009

Dissection of the carboxyl-terminal domain of the proteasomal subunit Rpn11 in maintenance of mitochondrial structure and function.

Mol Biol Cell 2008 Mar 2;19(3):1022-31. Epub 2008 Jan 2.

Pasteur Institute-Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome La Sapienza, 00185 Rome, Italy.

We have previously demonstrated that the C-terminal part of Rpn11, a deubiquitinating enzyme in the lid of the proteasome, is essential for maintaining a correct cell cycle and normal mitochondrial morphology and function. The two roles are apparently unlinked as the mitochondrial role is mapped to the Carboxy-terminus, whereas the catalytic deubiquitinating activity is found within the N-terminal region. The mitochondrial defects are observed in rpn11-m1 (originally termed mpr1-1), a mutation that generates Rpn11 lacking the last 31 amino acids. No mitochondrial phenotypes are recorded for mutations in the MPN+/JAMM motif. In the present study, we investigated the participation of the last 31 amino acids of the Rpn11 protein by analysis of intragenic revertants and site-specific mutants. We identified a putative alpha-helix necessary for the maintenance of a correct cell cycle and determined that a very short region at the C-terminus of Rpn11 is essential for the maintenance of tubular mitochondrial morphology. Furthermore, we show that expression of the C-terminal part of Rpn11 is able to complement in trans all of the rpn11-m1 mitochondrial phenotypes. Finally, we investigate the mechanisms by which Rpn11 controls the mitochondrial shape and show that Rpn11 may regulate the mitochondrial fission and tubulation processes.
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http://dx.doi.org/10.1091/mbc.e07-07-0717DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2262987PMC
March 2008

Participation of the proteasomal lid subunit Rpn11 in mitochondrial morphology and function is mapped to a distinct C-terminal domain.

Biochem J 2004 Jul;381(Pt 1):275-85

Pasteur Institute Cenci Bolognetti Foundation and the Department of Cell and Developmental Biology, University of Rome I, 00185 Rome, Italy.

Substrates destined for degradation by the 26 S proteasome are labelled with polyubiquitin chains. Rpn11/Mpr1, situated in the lid subcomplex, partakes in the processing of these chains or in their removal from substrates bound to the proteasome. Rpn11 also plays a role in maintaining mitochondrial integrity, tubular structure and proper function. The recent finding that Rpn11 participates in proteasome-associated deubiquitination focuses interest on the MPN+ (Mpr1, Pad1, N-terminal)/JAMM (JAB1/MPN/Mov34) metalloprotease site in its N-terminal domain. However, Rpn11 damaged at its C-terminus (the mpr1-1 mutant) causes pleiotropic effects, including proteasome instability and mitochondrial morphology defects, resulting in both proteolysis and respiratory malfunctions. We find that overexpression of WT (wild-type) RPN8, encoding a paralogous subunit that does not contain the catalytic MPN+ motif, corrects proteasome conformations and rescues cell cycle phenotypes, but is unable to correct defects in the mitochondrial tubular system or respiratory malfunctions associated with the mpr1-1 mutation. Transforming mpr1-1 with various RPN8-RPN11 chimaeras or with other rpn11 mutants reveals that a WT C-terminal region of Rpn11 is necessary, and more surprisingly sufficient, to rescue the mpr1-1 mitochondrial phenotype. Interestingly, single-site mutants in the catalytic MPN+ motif at the N-terminus of Rpn11 lead to reduced proteasome-dependent deubiquitination connected with proteolysis defects. Nevertheless, these rpn11 mutants suppress the mitochondrial phenotypes associated with mpr1-1 by intragene complementation. Together, these results point to a unique role for the C-terminal region of Rpn11 in mitochondrial maintenance that may be independent of its role in proteasome-associated deubiquitination.
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http://dx.doi.org/10.1042/BJ20040008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1133786PMC
July 2004
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