Search

Summary: The effects of N-terminal acetylation of the high molecular weight tropomyosin isoforms Tpm1.6 and Tpm2.1 and the low molecular weight isoforms Tpm1.12, Tpm3.1, and Tpm4.2 on the actin affinity and the thermal stability of actin-tropomyosin cofilaments are described. Furthermore, we show how the exchange of cytoskeletal tropomyosin isoforms and their N-terminal acetylation affects the kinetic and chemomechanical properties of cytoskeletal actin-tropomyosin-myosin complexes. Our results reveal the extent to which the different actin-tropomyosin-myosin complexes differ in their kinetic and functional properties. The maximum sliding velocity of the actin filament as well as the optimal motor density for continuous unidirectional movement, parameters that were previously considered to be unique and invariant properties of each myosin isoform, are shown to be influenced by the exchange of the tropomyosin isoform and the N-terminal acetylation of tropomyosin.

The crack susceptibility during processing has a crucial influence on the workability of wrought alloys. In particular, the processing of high-strength alloys that are prone to cracking is challenging and various process parameters have to be optimized to achieve a good formability. The polycrystalline CoNi-base superalloy CoWAlloy1 provides a high potential for high-temperature applications due to it having a large forging window, a high γ′ fraction and excellent creep properties. In order to study its formability during hot rolling, its deformation behavior and susceptibility to cracking were characterized by sub- and supersolvus compression tests at temperatures between 1000–1150 °C. At temperatures around the γ′ solvus temperature, no cracks formed during the compression testing, while at lower temperatures, cracking occurred. Additionally, an in-situ high-temperature small-angle neutron scattering revealed the phase fractions and the precipitate size distributions at different processing temperatures. It was found that a high fraction of γ′ forms during cooling and cracking starts at the surface of the bar, when the hot bar encounters the cold rolls during hot rolling. Apparently, the precipitation of γ′, which causes a high strength and reduced ductility, and the absent recrystallization leads to pronounced crack propagation and limited formability below the γ′ solvus temperature.

Filamentous fungi belonging to the genus Fusarium are notorious plant-pathogens that infect, damage and contaminate a wide variety of important crops. Phenamacril is the first member of a novel class of single-site acting cyanoacrylate fungicides which has proven highly effective against important members of the genus Fusarium. However, the recent emergence of field-resistant strains exhibiting qualitative resistance poses a major obstacle for the continued use of phenamacril. In this study, we synthesized novel cyanoacrylate compounds based on the phenamacril-scaffold to test their growth-inhibitory potential against wild-type Fusarium and phenamacril-resistant strains. Our findings show that most chemical modifications to the phenamacril-scaffold are associated with almost complete loss of fungicidal activity and in vitro inhibition of myosin motor domain ATPase activity.

The mechanical properties of low-pressure plasma sprayed (LPPS) MCrAlY (M = Ni, Co) bond coats, Amdry 386, Amdry 9954 and oxide dispersion strengthened (ODS) Amdry 9954 (named Amdry 9954 + ODS) were investigated after annealing in three atmospheres: Ar−O2, Ar−H2O, and Ar−H2−H2O. Freestanding bond coats were investigated to avoid any influence from the substrate. Miniaturized cylindrical tensile specimens were produced by a special grinding process and then tested in a thermomechanical analyzer (TMA) within a temperature range of 900−950 °C. Grain size and phase fraction of all bond coats were investigated by EBSD before testing and no difference in microstructure was revealed due to annealing in various atmospheres. The influence of annealing in different atmospheres on the creep strength was not very pronounced for the Co-based bond coats Amdry 9954 and Amdry 9954 + ODS in the tested conditions. The ODS bond coats revealed significantly higher creep strength but a lower strain to failure than the ODS-free Amdry 9954. The Ni-based bond coat Amdry 386 showed higher creep strength than Amdry 9954 due to the higher fraction of the β-NiAl phase. Additionally, its creep properties at 900 °C were much more affected by annealing in different atmospheres. The bond coat Amdry 386 annealed in an Ar−H2O atmosphere showed a significantly lower creep rate than the bond coat annealed in Ar−O2 and Ar−H2−H2O atmospheres.