4,413 research outputs found
A new species of the pollen-beetle genus Meligethes (Coleoptera: Nitidulidae) of the M. aeneus group from Greece, with review of the M. subaeneus complex.
No full textFIGURES 5–12. Tegmen and median lobe of aedeagus (dorsal view) of Meligethes coracinus Sturm (♂ specimen from Italy, Lombardia, Lovero Valtellino, Figs. 5–6), of M. subaeneus Sturm (♂ specimen from Italy, Latium, Rocca di Papa, Figs. 7–8), of M. matronalis Audisio & Spornraft (♂ specimen from Italy, Latium, Rocca di Papa, Figs. 9–10) and of Meligethes epeirosi n.sp. (♂ paratype from Greece, Katara Pass, Figs. 11–12). Scale bar = 0.50 mm.Published as part of Audisio, Paolo, Mancini, Emiliano & Biase, Alessio De, 2006, A new species of the pollenbeetle genus Meligethes (Coleoptera: Nitidulidae) of the M. aeneus group from Greece, with review of the M. subaeneus complex, pp. 43-60 in Zootaxa 1275 on page 51, DOI: 10.5281/zenodo.17330
La Grande Guerra: Segni e disegni del territorio
No full textL’ampio fervore di ricerche che si sta registrando, non solo in Italia, per la ricorrenza del
Centenario della Grande Guerra (1914-1918) è proporzionale alla pluralità e, soprattutto, alla
complessità delle questioni legate alla vicenda bellica: accanto alle indagini, attese, sui temi più
strettamente storico-politici e sulle azioni militari, si moltiplicano in altri settori ricerche tese
a far luce su aspetti collaterali, ma non secondari, del conflitto, dalla sua rappresentazione agli
effetti che produsse sulla vita degli Italiani, all'organizzazione del Paese di fronte alla guerra
e dopo la guerra. Il presente volume raccoglie i contributi di studiosi che pongono al centro
della loro ricerca il territorio e ne indagano, da punti di vista diversi, i segni connotativi durante
gli anni del conflitto
Genes
No full textThe adaptation of microorganisms to low pH has many important practical applications in a number of diverse sectors such as food and drink microbiology, industrial biotechnology and bio-processing, and clinical and veterinary treatment of infections, in a time of increasing antimicrobial resistance. The microorganisms under consideration include bacteria, yeasts, and other fungi. With this Special Issue, we aim to collect high-quality research articles describing the genomic, transcriptomic, sensing, and metabolic landscape of the microbial responses to low pH with a view to understanding their functional significance and bridging to potential applications gathered from the covered knowledge. We wish to cover all aspects of the molecular events from sensing to responding to low pH stress, and also to cover descriptions of genes in different organisms that may have specific functions at low pH. Adaptation is therefore meant both in terms of the short-term response, and also in the description of how evolution has enabled microorganisms to be resilient to acid stress. This is in line with the objectives of the COST Action “EuroMicropH” (https://euromicroph.eu), which is committed to aiding the understanding of the details of how model and non-model micro-organisms detect and respond to low pH.
Prof. Daniela De Biase
Dr. Peter A. Lund
Prof. Nuno Pereira Mira
Guest Editor
O concredo armado: problemas de restauro. Entrevista com a arquiteta restauradora Carolina Di Biase. Entrevista e traduçào: A. Coelho Sanches
No full textIl concetto di conoscenza e il problema della fondazione della cultura nel giovane Natorp
No full textThis contribution shows that, already at its origins, the philosophical system of Natorp presents a logical scheme for a philosophy of culture. The contribution focuses on Natorp's work of 1887 on the objective and subjective foundation of knowledge
A new species of Meligethes (Coleoptera: Nitidulidae: Meligethinae) of the M. lugubris complex from Sardinia.
No full textA combined morphological and bionomical analysis was performed to clarify the position of a problematic species of the
Meligethes lugubris group from Sardinia and Corsica (Coleoptera, Nitidulidae, Meligethinae). This species-group is
represented by a dozen anthophagous species associated with Lamiaceae, and distributed from North Africa to Japan.
The analysis was mainly focused on the specific distinction and formal description of a new species, M. foddaii Audisio,
De Biase & Trizzino sp. nov., from Sardinia and Corsica. The species is morphologically scarcely distinguishable from
the allopatric M. lugubris Sturm and M. gagathinus Erichson (both widespread in southern Europe). An identification
key to Euro-Mediterranean members of the M. lugubris complex is provided. Combined morphological, ecological,
phenological, and preliminary molecular data are presented to support the distinction of the new species. The
palaeogeographical scenario explaining the likely Plio-Pleistocene differentiation of the three species, which are all
associated with the related Lamiaceae genera Mentha and Thymus, is also briefly discussed
The role of an active site aspartate residue in the catalytic activity of Glutamate decarboxylase from Escherichia coli.
No full textThe EMBO Conference focuses on fundamental and applied aspects of biocatalysis, with an emphasis on the impact that enzyme research has at the interface of biology and chemistry. The sessions will cover an array of topics including computational, chemistry and structural approaches, as well as directed evolution, bioinformatics and spectroscopic methods, aimed towards better understanding of enzyme mechanisms and mechanisms of complex multifunctional enzyme systems, in vitro and in vivo. The importance of the electrostatic and dynamical properties of enzymes will be addressed. The impact of this knowledge for drug discovery research and research on non-natural biocatalytic systems will be highlighted. Established and emerging scientists from academic and industrial settings will be available to stimulate discussion and provide perspective on the topics of this conference. We strongly encourage participation of students and postdoctoral associates, providing opportunities for discussion and networking. Oral presentations chosen from submitted poster abstracts will provide additional opportunities for discussing new and innovative ideas. The speakers are encouraged to give a brief introduction of the field in which they work and allow for sufficient time for discussion.Escherichia coli glutamate decarboxylase is a homohexameric PLP-dependent enzyme and a major structural component of the glutamate-based acid resistance system in this microorganism as well as in many orally-acquired, neutralophilic bacteria [1,2]. In fact the decarboxylation of L-glutamate, besides yielding γ-aminobutyrate (GABA) and CO2, consumes 1 H+/catalytic cycle, an activity shown to be beneficial for protecting the cell under extreme acid stress [1]. We have extensively characterized one of the two E. coli isoforms, the B isoform (EcGadB) and shown that it displays pH-dependency in activity in the acid range, being maximally active at pH 4-5 while showing negligible or no activity at or above pH 6.5. Based on the crystal structures of EcGadB at neutral and acidic pH, as well as in the presence of halides, and of a mutant form deleted at the N-terminal, we hypothesize that together with His465 (the penultimate residues in the amino acid sequence), Asp86 is a likely candidate for controlling the acidic range of activity of EcGad [3,4]. Notably, both residues are highly conserved in bacterial Gad [1]. The contribution to EcGadB spectroscopic and catalytic properties by His465, a critical residue for controlling active site access, was previously investigated [5].
In the present work, we carried out detailed biochemical characterization of the EcGadB-Asp86 mutant. However, in order to appreciate the contribution of Asp86 to the catalytic properties of EcGadB, it was necessary to incorporate the mutation Asp86→Asn in the mutant GadB_H465A, thereby avoiding the masking effect of His465 at pH>5.5. Our data show that, unlike wild-type EcGadB and GadB_H465A, the double mutant GadB_D86N¬-H465A, while retaining substrate specificity, is a more robust catalyst in the pH range 7-8 and displays an altered solvent kinetic isotope effect. Hence, GadB_D86N¬-H465A is less sensitive to pH increase during the decarboxylation reaction.
We proposed that immobilization of EcGadB can be exploited for GABA synthesis at the industrial level [6]. GABA in turn can be used as precursor of 2-pyrrolidone, an industrial solvent, and of nylon 4. Thus mutant forms of EcGadB less sensitive to pH increase (i.e. > 5.5) are highly desirable. Based on our data, pH is no longer a limiting reaction parameter for GadB_D86N¬-H465A.
References
[1] De Biase D, Pennacchietti E. (2012) Mol. Microbiol 86: 770-86.
[2] Lund P, Tramonti A, De Biase D. (2014) FEMS Microbiol Rev 38: 1091–125.
[3] Capitani G, De Biase D, et al. (2003) EMBO J. 22: 4027-4037.
[4] Gut H, Pennacchietti E, et al. (2006) EMBO J. 25: 2643-2651.
[5] Pennacchietti E, Lammens TM, et al. (2009) J Biol Chem. 284: 31587-96.
[6] Lammens TM, De Biase D, et al. (2009) Green Chemistry 11: 1562-67
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