Incorporating spin-orbit effects into surface hopping dynamics using the diagonal representation: a linear-response time-dependent density functional theory implementation with applications to 2-thiouracil.

In this study, we present a trajectory surface hopping (TSH) method that incorporates spin-orbit (SO) effects using the "diagonal representation" within the Linear-Response Time-Dependent Density Functional Theory (LR-TDDFT) framework. In this approach, the evaluation of spin-orbit coupling (SOC) matrix elements between singlet and triplet states employs the Casida's wave functions and the Breit-Pauli (BP) spin-orbit Hamiltonian with effective charge approximation. The new TSH approach is then used to investigate the excited-state relaxation of 2-thiouracil (2TU) in vacuum and water. On the basis of the simulation results, relaxation of the initially populated bright state is found to be dominated by the route S2 → S1 → T. The intersystem crossing (ISC) can occur at either the C2-puckered structure or the C2-pyramidalized S1 minimum, and is promoted by a three-state near-degeneracy (S1/T2/T1 in vacuum or S1/T3/T2 in water) as well as sizable SOCs. Our simulations achieve a good agreement with the available experimental measurements in terms of the internal conversion (IC) and ISC time scales, and complement the picture of the relaxation mechanisms of 2TU after photo-excitation to the first bright state.

The function of snodprot in the cerato-platanin family from Dactylellina cionopaga in nematophagous fungi.

Dactylellina cionopaga is a potential biocontrol agent of phytoparasitic nematodes. Here the functions of snodprot of D. cionopaga were analysed. The gene was transcribed with a higher level under inducing conditions with nematodes. The recombinant protein expressed in Pichia pastoris had a molecular weight of 14 kDa and might form polymers in its native state. In a concentration-dependent manner, snodprot changed the chemotaxis and increased the body-bend frequency of Caenorhabditis elegans, but did not induce immunity in the indicated plants significantly. The results of an immunofluorescence assay proved that snodprot was expressed during the development of traps and conidia. According to the parasitism mechanisms of nematophagous fungi and the chemotaxis and locomotion mechanisms of C. elegans, the possible active sites of snodprot were speculated to be ASE or ASI. The gene identification indicated that snodprot is a novel parasitism-related protein of nematophagous fungi, and possesses novel activity, different from other members of the cerato-platanin family.

Characterization of an extracellular serine protease gene from the nematophagous fungus Lecanicillium psalliotae.

The gene encoding a cuticle-degrading serine protease was cloned from three isolates of Lecanicillium psalliotae (syn. Verticillium psalliotae) by 3' and 5' RACE (rapid amplification of cDNA ends) method. The gene encodes for 382 amino acids and the protein shares conserved motifs with subtilisin N and peptidase S8. Comparison of translated cDNA sequences of three isolates revealed one amino acid polymorphism at position 230. The deduced protease sequence shared high degree of similarities to other cuticle-degrading proteases from other nematophagous fungi.