Contribution to the knowledge of the genus Phlebia in Italy

The presence of two corticioid taxa belonging to the genus Phlebia (Basidiomycota), collected from Sicily, Italy is reported. A macro- and micromorphological descriptions of P. acanthocystis and P. nothofagi added of ecological and distributional data are here provided. P. acanthocystis is reported as new for Italy.

Reaction volume and rate constants for the Excited State Proton Transfer in aqueous solutions of Naphthols

In this Letter we report the time-resolved determination of the volume changes for the excited-state deprotonation of 1-naphthol, 2-naphthol and 1-naphthol-3,6-disulphonate and the neutralization of the ground-state naphtholate anions with the protons free in solution. Photoexcitation of the naphthols leads to a fast contraction of the solution due to the solvation of the newly formed ions and is followed by an expansion of equal extent, due to the back recombination reaction. The apparent rate constant of the recombination reaction depends on the concentration of protons free in solution in accordance with a pseudo-first-order reaction model

New records of corticioid fungi from Sicily

This paper is the result of an on-going study on distribution and ecology of corticioid wood-inhabiting fungi in Sicily. Twenty-five species not previously recorded in Sicily are here listed. For each taxon, ecological and distributional data are provided. Subulicystidium perlongisporum was recorded in Italy for the first time in two localities occurring on Quercus ilex L. wood. Description, distributional and ecological data of this rare taxon are also provided. Dendrophora versiformis and Kavinia alboviridis, considered rare species in Italy and Europe, are included in this report

Flavin Mononucleotide-binding fluorescent proteins

Flavin mononucleotide (FMN)-binding fluorescent proteins (FbFPs) are novel reporters for cell microscopy, outperforming green fluorescent proteins (GFP) and derivatives in anaerobic or microaerobic environments (Figure 1). Furthermore they are better suited for incorporation into small-sized genomes and for following viral infections, protein expression and protein maturation in real-time (figure 2, 3). FbFPs are derived from photoreceptors of the LOV (Light, Oxygen Voltage) superfamily and exhibit fluorescence in the green region of the spectrum with quantum yield of ca. 0.2-0.3. FbFPs have been introduced as fluorescent reporters in 2007 and have been ever since exploited for a number of selected applications, including real-time biosensing of changing oxygen level within living cells

Photoinduced structural volume changes in aqueous solutions of blepharismin

Employing time-resolved photoacoustics we measured the structural volume changes (ΔVri) occurring after photo-excitation of blepharismin (BPR) aqueous solutions; an expansion occurring in the subnanosecond timescale is followed by a back contraction within some hundreds of nanoseconds. The magnitude of the ΔVri strongly depends on pH, allowing the determination of the pKa of BPR with this method. The values so measured are very close to those found by means of UV-visible absorption spectroscopy. The presence of water-soluble electron acceptors or donors (hexacyanoferrate [III] hexacyanofer-rate [II]) as well as the concentration of oxygen do not affect the magnitude or the kinetics of the structural volume changes. On the contrary, we detect a strong deuterium effect; this suggests that the observed ΔVri are related to an altered hydrogen bond pattern of the excited state of the pigment with respect to the ground state. Comparative measurements with the parent compound hypericin are also reported, suggesting that the photo-induced expansion-contraction pattern is a general characteristic of polyhydroxylated quinones

Porphyrin-Melanins interaction: effect on fluorescence and nonradiative relaxations

Optical techniques and pulsed-laser, time-resolved photoacoustics (PA) were employed to obtain information on the mechanism of interaction between cationic zinc tetrabenzilpyridilporphyrin (ZnTBzPyP) and synthetic l-Dopa melanins. Synthetic eumelanin and pheomelanin strongly quench the fluorescence of ZnTBzPyP, but Stern-Volmer plots suggest a mechanism of interaction quite different for the two pigments. This diversity was confirmed by PA: for eumelanin no thermal relaxation was observed other than prompt heat, whereas for the complexed form of ZnTBzPyP with pheomelanin we were able to detect a heat-emitting species with a non-radiative lifetime in the microsecond range. The involvement of oxygen in the photophysics of the complexes formed between the cationic porphyrin and the two pigments was demonstrated, but its role has yet to be described

Diversity of polypores in the Dominican Republic: Pseudowrightoporia dominicana sp. nov. (Hericiaceae, Russulales)

Volume: 34Start Page: 35End Page: 4

Kinetics of conversion between Pr and Pfr states in three prototypical bacteriophytochromes

Bacteriophytochromes (PphPs) show strong structural similarity to canonical phytochromes, however, they employ as chromophore biliverdin IX instead of phytochromobilin (plant phytochromes) or phycocyanobilin (cyanobacterial phytochromes). This change of chromophore shifts the absorption maxima – compared to those of the plant phytochromes – for both Pr and Pfr state further into the red- / far red range of the spectrum (to 700 and 750 nm, respectively), and thereby makes these phytochromes very well suited for biomedical applications (1). Both photochromic states are reported, however, the dynamics of laser flash-induced conversion between both states has not been studied in detail. Here, we present the kinectics of Pr-to-Pfr conversion (and vice versa) for three prototypal bacteriophytochromes, as such phy1 from Pseudomonas (P.) syringae pv. tomato (PstBphP1), phytochrome from P. aeruginosa (PaBphP), and phytochrome from the fungus Aspergillus nidulans (FphA). Whereas the phytochrome from P. syringae and ist fungal ortholog are formed biosynthetically in the Pr state with absorption maxima at 700 nm, the phytochrome from P. aeruginosa is generated in its Pfr state (750 nm), thus being called a bathy-phytochrome. The conversions between both states of all three bacteriophytochromes in the time range of ca. 1 us up to 20 ms are much more simple than comparable kinetics found for canonical phytochromes from plants (oat phyA) or from cyanobacteria (Cph1, CphA, 2,3). Whereas in the latter proteins a sequence of intermediates can be clearly identified, the bacteriophytochromes run through one intermediate, or in some cases a direct formation of the final photoproduct is immediately observed. 1) Chernov, K.G. et al. (2017) Chem. Rev. 117 6423-6446. 2) Gärtner, W. and Braslavsky, S.E. (2003) In: Photoreceptors and light signalling, Batschauer, A. (ed.). Compr. Series Photochem. Photobiol. Sci., Vol. 3, Batschauer, A. (ed.), Häder, D.-P. and Jori, G. (series eds.), Royal Soc. Chemistry, Cambridge, UK, pp. 136-180. 3) Remberg, A. et al. (1997) Biochemistry 36 13389-13395