1,616 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
MOLECULAR TAXONOMY OF TWO SYMPATRIC SIBLING SPECIES OF THE POLLEN-BEETLE GENUS MELIGETHES (COLEOPTERA: NITIDULIDAE).
No full textFIGURE 2. Neighbor Joining based on K2P pair wise distances matrix for COII. Refer to Table 1 for specimens acronyms. In parentheses bootstrap values scored for the NJ analysis based on the uncorrected p distance values.Published as part of Biase, Alessio De, Antonini, Gloria, Mancini, Emiliano & Sio, Paolo Audi-, 2003, Molecular taxonomy of two sympatric sibling species of the pollenbeetle genus Meligethes (Coleoptera: Nitidulidae), pp. 1-16 in Zootaxa 190 (1) on page 9, DOI: 10.11646/zootaxa.190.1.1, http://zenodo.org/record/509366
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
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
Le cellule staminali mesenchimali in Ortopedia. Quali, come, perché
No full textLa biologia ossea e le cellule staminali sono sempre state intimamente legate fin dagli inizi della medicina sperimentale. Questo già molto tempo prima che il termine di Medicina Rigenerativa divenisse abusato nella letteratura. Le cellule staminali presenti nell’osso sono state studiate approfonditamente ed in particolare la contemporanea presenza di due linee cellulari come l’ematopoietica e l’osteogenica ha sempre raccolto l’interesse della scienza. A tale riguardo il trapianto di cellule staminali ematopoietiche prelevate dal midollo osseo ed espanse in vitro rappresenta una delle maggiori innovazioni scientifiche nel campo della biologia applicata alla terapia. Dopo questo successo l’idea di poter utilizzare il prelievo di cellule mesenchimali per il trattamento delle patologie ossee ha trovato un nuovo impulso e il recente concetto di “nicchia” ha spinto ulteriormente avanti la nostra comprensione del funzionamento delle cellule rendendo possibile l’inizio di studi mirati al trattamento delle condropatie degenerative, delle necrosi epifisarie, l’osteoporosi e le mancate guarigioni delle fratture
Dimensione finanziaria ed impatti locali della programmazione comunitaria e nazionale. Il caso del Matese in Campania
No full textl contributo prende spunto dalle attività sviluppate nell’ambito del progetto “Riabitare i Paesi. Strategie Operative per la Valorizzazione e la Resilienza delle Aree Interne”(RI.P.R.O.VA.RE) ed è finalizzato ad una prima valutazione degli impatti a scala locale degli investimenti pubblici di tipo straordinario della programmazione comunitaria e nazionale. Definiti alcuni indicatori quantitativi, in basealla disponibilità di dati alla scala comunale, se ne proponeuna applicazione nell’ambito territoriale del Matese nella Provincia di Caserta. L’esercizio valutativointendeavviare, dopouna ricostruzione del quadro della progettualità locale, una prima riflessione sugli impatti dei più significativi investimenti pubblici ascala locale, in particolare nelle aree interne, per promuovere più efficaci politiche di sviluppo. A tal proposito, la definizione di indicatori calcolabili alla scala comunale, riferitiad alcuni degli obiettivi dell’Agenda 2030, potrebbe supportare più efficaci ed efficienti progetti e programmi di sviluppo locale
Quel che resta delle cose. Riccardo de Biase lettore di Heidegger
No full textF. Brencio (2023), Quel che resta delle cose. Riccardo de Biase lettore di Heidegger, in G. Giannini, P. Marangolo, M. Papa (eds.), Segni. Studi in memoria di Riccardo De Biase, TAB Edizioni, Roma 2023, pp. 171-182, ISBN: 978-88-9295-769-5
Quel che resta delle cose. Riccardo de Biase lettore di Heidegger
No full textF. Brencio (2023), Quel che resta delle cose. Riccardo de Biase lettore di Heidegger, in G. Giannini, P. Marangolo, M. Papa (eds.), Segni. Studi in memoria di Riccardo De Biase, TAB Edizioni, Roma 2023, pp. 171-182, ISBN: 978-88-9295-769-5
Hydraena rosannae Audisio, Trizzino & De Biase 2009, sp. nov.
No full text<i>Hydraena rosannae</i> Audisio, Trizzino & De Biase, sp. nov. <p>(Figs 1, 7–8, 11)</p> <p> <b>Diagnosis.</b> Small-sized (length 1.94–2.21 mm), elongate orange species with yellowish to orange legs and antennae; pronotum 0.62–0.81 times width of combined maximum elytral width (Fig. 1). Similar to the widespread Sardinian <i>H. tyrrhena</i> Binaghi, 1961 and to the Corsican <i>H. evanescens</i> Rey, 1884, recently redescribed by Audisio and De Biase (1995), but with a much less deep emargination on dorsal profile of aedeagus (in lateral view), slightly more inflated apical portion of male hind tibiae, and slightly sinuose and dilated middle portion of male front tibiae (Fig. 1).</p> <p> <b>Type material.</b> Holotype ♂: Italy, Sardinia (Medio Campidano province), above Villacidro, Cannisoni River, 390 m a.s.l., 39.24. 37.28 N, 8.38. 27.39 E, 19.V.2008, M. Trizzino, P. Audisio, G. Nardi & M.Bardiani leg. (CAR).</p> <p>Paratypes: same data as holotype, 2 ♂, 3 ♀♀ (CAR, CDL, CDM).</p> <p> <b>Description.</b> Male [measurements refer to holotype]. Length (apex of labrum – apex of pygidium) 2.21 mm; breadth (at elytral widest point) 0.70 mm, pronotal breadth 0.57 mm. Elongate, scarcely convex (Fig. 1), orange with shiny reflections. Legs, antennae and lateral edges of pronotum yellowish to pale orange.</p> <p> Labrum with deep, V-shaped notch anteriorly; margins very slightly upturned. Fronto-clypeal suture almost straight. Middle of frons moderately densely punctate, interstices shining; lateral portions of frons densely and rugosely punctate, punctures and interstices microreticulate; paraocular grooves shallow. Eyes moderately large, protruding, with more than 20 facets visible in dorsal view. Maxillary palpi very long, about twice as long as distance between eyes. Antennae small, of normal shape for members of the <i>Haenydra</i> lineage (Fig. 1).</p> <p>Pronotum nearly exagonal, about 1.15 times wider than long; anterior margin slightly concave; anterior angles slightly obtuse; lateral margin moderately produced at middle, strongly convergent at anterior angle, sinuately convergent at posterior angle; lateral rim minutely crenulate; disc moderately convex, sparsely to moderately densely punctate, more densely punctate near anterior and posterior margins, smooth and punctate between punctures, foveae hardly perceptible; anterior and posterior sublateral foveae well impressed, elongate; lateral portion of pronotum evenly deflexed, sparsely punctate (Fig. 1).</p> <p>Elytra elongate, nearly 1.8 times as long as their combined width, slightly and regularly arcuate at sides, apically produced and only very weakly declivitous; moderately declivitous laterally; with seven rows of punctures between suture and shoulder; strial punctures moderately large, distinctly impressed and forming regular lines moderately deeply impressed in middle of each elytron; punctures rather densely arranged within lines; intervals and interstices almost flat and glabrous or superficially microreticulate; intervals slightly wider than one puncture diameter; explanate margin and pseudepipleura relatively narrow and long, not reaching apex (Fig. 1).</p> <p>Pygidium in male as in Fig. 1.</p> <p>Mentum and submentum microreticulate. Transverse genal ridges not very prominent, glabrous.</p> <p>Prosternum with median keel. Mesoventrite with a pair of sublateral distinct glabrous streaks; very deeply impressed between disc and posterior process. Metaventral disc shallowly impressed between well developed, posteriorly divergent plaques.</p> <p>First ventrite without glabrous areas behind metacoxal sockets; abdominal sternites III–VI more or less entirely covered with hydrofuge pubescence; abdominal sternites VII and VIII largely glabrous.</p> <p>Aedeagus (Figs 7–8): main piece (length ca. 472 µm) oriented as in Figs 7–8, with only two small, short, and hardly distinct setae on left side, apparently without setae on right side; distinctly bisinuous in apical half (dorsal view); with subtruncate projection before the middle (dorsal view), and with proximal obtuse projection on dorsal side of apical fifth; apical third short and thick (lateral view), apex acute; dorsal outline (lateral view) with a very wide and shallow arcuate emargination at distal third; prebasal tooth (lateral view) not very prominent.</p> <p>Phallobase more or less symmetrical (in dorsal view). Distal mobile lobe small, elongate, composed of two parts: an elongate piece and a very thin and short flagellum.</p> <p>Secondary sexual characters. Male elytral apices convergent posteriorly, slightly conjointly rounded (Fig. 1); in female only slightly more acuminately convergent (with small sutural notch). Male femora slightly more strongly built. Male protibiae slightly but distinctly dilated and hardly curved along their inner edge. Male mesotibia not dilated subapically, with a row of short spines and 11–12 minute denticles along their inner edge. Male metatibia slightly but distinctly dilated in distal half, with fringe of very long hairs along their inner edge.</p> <p>Female. Last abdominal tergite and sternite as in Figs 9–10.</p> <p> <b>Variability.</b> Length variable between 1.94 and 2.21 mm.</p> <p> <b>Distribution.</b> Known with certainty only from the Sulcis-Iglesiente area around Villacidro (Medio Campidano province), SW Sardinia.</p> <p> <b>Biological notes.</b> The type specimens were collected under stones in a stream with relatively fast-running water, on a granodioritic substrate, at nearly 400 m a.s.l.</p> <p> <b>Etymology.</b> This species is named after Mrs Rosanna Calabrò (M.T.’s wife).</p>Published as part of <i>Audisio, Paolo, Trizzino, Marco, Biase, Alessio De, Mancini, Emiliano & Antonini, Gloria, 2009, A new species of Hydraena (Coleoptera: Hydraenidae) of the H. evanescens complex from Sardinia *, pp. 281-289 in Zootaxa 2318</i> on pages 283-28
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