פרסומים

We are very pleased to present this Festschrift in honor of our colleague, mentor and friend Prof. Volker Buß, which was initiated to celebrate his 75th birthday. The aim of this special issue is to recollect his substantial contributions and achievements of his career in the field of Theoretical/Computational Photochemistry. This article is protected by copyright. All rights reserved.

Biologically active recombinant yellowtail kingfish follicle stimulating hormone (rytkFsh) was produced in yeast Pichia pastoris and its biological activity was demonstrated by both in-vitro and in-vivo bioassays. Incubation of ovarian and testicular fragments with the recombinant hormone stimulated E2 and 11-KT secretion, respectively. In-vivo trial in immature female YTK resulted in a significant increase of plasma E2 levels and development of oocytes. In males at the early stages of puberty, advancement of spermatogenesis was observed, however plasma 11-KT levels were reduced when administered with rytkFsh.

Biologically active recombinant yellowtail kingfish follicle stimulating hormone (rytkFsh) was produced in yeast Pichia pastoris and its biological activity was demonstrated by both in-vitro and in-vivo bioassays. Incubation of ovarian and testicular fragments with the recombinant hormone stimulated E and 11-KT secretion, respectively. In-vivo trial in immature female YTK resulted in a significant increase of plasma E levels and development of oocytes. In males at the early stages of puberty, advancement of spermatogenesis was observed, however plasma 11-KT levels were reduced when administered with rytkFsh.

Tomato yellow leaf curl virus (TYLCV), a begomovirus, induces protein aggregation in infected tomatoes and in its whitefly vector Bemisia tabaci. The interactions between TYLCV and HSP70 and HSP90 in plants and vectors are necessity for virus infection to proceed. In infected host cells, HSP70 and HSP90 are redistributed from a soluble to an aggregated state. These aggregates contain, together with viral DNA/proteins and virions, HSPs and components of the protein quality control system such as ubiquitin, 26S proteasome subunits, and the autophagy protein ATG8. TYLCV CP can form complexes with HSPs in tomato and whitefly. Nonetheless, HSP70 and HSP90 play different roles in the viral cell cycle in the plant host. In the infected host cell, HSP70, but not HSP90, participates in the translocation of CP from the cytoplasm into the nucleus. Viral amounts decrease when HSP70 is inhibited, but increase when HSP90 is downregulated. In the whitefly vector, HSP70 impairs the circulative transmission of TYLCV; its inhibition increases transmission. Hence, the efficiency of virus acquisition by whiteflies depends on the functionality of both plant chaperones and their cross-talk with other protein mechanisms controlling virus-induced aggregation. © 2017 Gorovits and Czosnek.

An appealing alternative approach to the conventional electro-chemical deposition is presented, which can be universally utilized to form nanomaterial coatings from their aqueous dispersions without involving their oxidation-reduction. It is based on altering the ionic strength by electrical potential in the vicinity of the electrode surface, which causes the nanomaterials to deposit. The concept has been demonstrated for four different systems.

An appealing alternative approach to the conventional electro-chemical deposition is presented, which can be universally utilized to form nanomaterial coatings from their aqueous dispersions without involving their oxidation-reduction. It is based on altering the ionic strength by electrical potential in the vicinity of the electrode surface, which causes the nanomaterials to deposit. The concept has been demonstrated for four different systems.

An appealing alternative approach to the conventional electrochem. deposition is presented, which can be universally utilized to form nanomaterial coatings from their aq. dispersions without involving their oxidn.-redn. It is based on altering the ionic strength by elec. potential in the vicinity of the electrode surface, which causes the nanomaterials to deposit. The concept has been demonstrated for four different systems. [on SciFinder(R)]

A new redox-free electrochemical approach for driving the deposition of two-dimensional (2D) layered MoS2 nanosheets is described. First, poly(acylic acid) (PAA) functionalized layered MoS2 nanosheets (PAA-MoS2) is prepared to form a stable aqueous PAA-MoS2 dispersion, which is subsequently used for the electrochemical deposition. In contrast to previous electrodeposition methods of MoS2, which involve the redox of molecular precursors of Mo and S, herein we introduce an electrochemical approach for the deposition of 2D layered MoS2 nanosheets directly from their nanometric building blocks, namely from their aqueous dispersion. This ‘‘nano to nano’’ approach is based on altering the ionic strength at the vicinity of the electrode surface by applying a potential. Specifically, the electrogeneration of Cue-1 ions, cause the PAA-MoS2 nanosheets in the dispersion to aggregate and deposit on the copper electrode. Scanning electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopy analysis show clearly that the deposited layered MoS2 maintains its original structure. Furthermore, the ;electrodeposited PAA-MoS2 nanosheets on copper show excellent catalytic activity for the hydrogen evolution reaction with low overpotential. Hence, we believe that these findings could lead to a generic approach for the formation of thin films or patterns of 2D nanomaterials. (C) 2017 Elsevier Ltd. All rights reserved.

Reversible storage of hydrogen in the form of stable and relatively harmless chemical substances such as formic acid (FA) is one of the cornerstones of a fossil-fuel-free economy. Recently, Ru(III)-PC(sp3)P (where PC(sp3)P = modular dibenzobarrelene-based pincer ligand possessing a pendant functional group) complex 1 has been reported as a mild and E-selective catalyst in semihydrogenation of alkynes with stoichiometric neat formic acid. Discovery of the additive-free protocol for dehydrogenation of FA launched further studies aiming at the rational design of highly efficient catalysts for this reaction operating under neutral conditions. We now report the results of our investigation on a series of bifunctionl PC(sp3)P complexes equipped with different outer-sphere auxiliaries, that allowed us to identify an amine-functionalized Ir(III)-PC(sp3)P complex 3, as a clean and efficient catalyst for the FA dehydrogenation. The catalyst is suitable for fuel-cell applications demonstrating a TON up to 5 × 105 and TOF up to 2 × 104 h–1 (3.8 × 105 and 1.2 × 104 h–1 with no additives). In addition to the practical value of the catalyst, experimental and computational mechanistic studies provide rationale for the design of improved next-generation catalysts.Reversible storage of hydrogen in the form of stable and relatively harmless chemical substances such as formic acid (FA) is one of the cornerstones of a fossil-fuel-free economy. Recently, Ru(III)-PC(sp3)P (where PC(sp3)P = modular dibenzobarrelene-based pincer ligand possessing a pendant functional group) complex 1 has been reported as a mild and E-selective catalyst in semihydrogenation of alkynes with stoichiometric neat formic acid. Discovery of the additive-free protocol for dehydrogenation of FA launched further studies aiming at the rational design of highly efficient catalysts for this reaction operating under neutral conditions. We now report the results of our investigation on a series of bifunctionl PC(sp3)P complexes equipped with different outer-sphere auxiliaries, that allowed us to identify an amine-functionalized Ir(III)-PC(sp3)P complex 3, as a clean and efficient catalyst for the FA dehydrogenation. The catalyst is suitable for fuel-cell applications demonstrating a TON up to 5 × 105 and TOF up to 2 × 104 h–1 (3.8 × 105 and 1.2 × 104 h–1 with no additives). In addition to the practical value of the catalyst, experimental and computational mechanistic studies provide rationale for the design of improved next-generation catalysts.

Identifying the metal ions that optimize charge transport and charge density in metal–organic frameworks is critical for systematic improvements in the electrical conductivity in these materials. In this work, we measure the electrical conductivity and activation energy for twenty different MOFs pertaining to four distinct structural families: M₂(DOBDC)(DMF)₂ (M = Mg²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺); H₄DOBDC = 2,5-dihydroxybenzene-1,4-dicarboxylic acid; DMF = N,N-dimethylformamide), M₂(DSBDC)(DMF)₂ (M = Mn²⁺, Fe²⁺; H₄DSBDC = 2,5-disulfhydrylbenzene-1,4-dicarboxylic acid), M₂Cl₂(BTDD)(DMF)₂ (M = Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺; H₂BTDD = bis(1H-1,2,3-triazolo[4,5-b],[4′,5′-i]dibenzo[1,4]dioxin), and M(1,2,3-triazolate)₂ (M = Mg²⁺, Mn²⁺, Fe²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺). This comprehensive study allows us to single-out iron as the metal ion that leads to the best electrical properties. The iron-based MOFs exhibit at least five orders of magnitude higher electrical conductivity and significantly smaller charge activation energies across all different MOF families studied here and stand out materials made from all other metal ions considered here. We attribute the unique electrical properties of iron-based MOFs to the high-energy valence electrons of Fe²⁺ and the Fe^3+/2+ mixed valency. These results reveal that incorporating Fe²⁺ in the charge transport pathways of MOFs and introducing mixed valency are valuable strategies for improving electrical conductivity in this important class of porous materials.

We used the photoacid 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS) that converts blue photons to acidic protons in water, with an efficiency of close to 100%, and determined that this treatment conferred changes to colony morphology of the plant pathogen Colletotrichum gloeosporioides. The time elapsed until hyphal collapse is noticed depends on both the laser intensity in mW/cm2, and the concentration of HPTS in the Agar hydrogel. The time elapsed until hyphal collapse is noticed varies by only ±8% at HPTS concentrations of 500μM and at lower concentrations of HPTS the variance increases as the inverse of the concentration. We found that the effect on C. gloeosporioides was photoacid concentration and irradiation dose dependent. In the presence of 500μM of HPTS within the agar hydrogel-based medium, hyphae collapsed after 37±3.5min of irradiation at 405nm at an intensity of 25mW/cm2. We propose two mechanisms for such photo-alteration of C. gloeosporioides. One is based on the pH drop in the extracellular environment by the photo-protolytic process that the photoacid molecule undergoes. The second mechanism is based on an intracellular mechanism in which there is an uptake of HPTS into the interior of the fungus. We suggest that both mechanisms for photo-alteration which we found in this study may occur in plants during fungal infection.