D-Alaninol

The supramolecular chemistry at surfaces has been extensively studied by quantum and classical computational models in order to simulate and reproduce the correct energetics and structures of adsorbed molecules on surfaces at various coverages. We have developed a classical tool able to sample the configuration space overcoming the topological constraints of the standard classical molecular dynamics. Our model is based on the charge equilibration procedure combined with an anisotropic pairwise atomic interaction where an angular dependence, with respect to the metal surface, is explicitly taken into account. The d-alaninol molecule has been chosen as a prototype of a flexible and multifunctional chemical compound which can form manifold complex configurations upon absorption on a metal surface. A detailed analysis of molecular structures and energetics of partial and full coverage has been carried out. The experimental STM image of the monolayer is correctly reproduced by our calculations, indicating that this new approach represents a step forward in the efficient simulation of complex molecular self-assembly.

Natriuretic peptide receptor A (NPR-A) agonists were evaluated in vivo by optimizing the structure of quinazoline derivatives to improve agonistic activity for rat NPR-A. A 1,4-Cis-aminocyclohexylurea moiety at 4-position and hydroxy group of d-alaninol at 2-position on the quinazoline ring were found to be important factors in improving rat NPR-A activity. We identified potent quinazoline and pyrido[2,3-d]pyrimidine derivatives against rat NPR-A, with double-digit nanomolar EC50 values. The in vivo results showed that compound 56b administered at 1.0 mg/kg/min significantly increased plasma cGMP concentration and urine volume in rats. We discovered novel potent NPR-A agonists that showed agonistic effects similar to those of atrial natriuretic peptide.

Objective: This study characterized the phylogenetic diversity of soil bacteria producing nematode-attracting volatiles and their nematode-attracting compounds. Results would enhance our understanding on the interaction between nematodes and soil microorganisms and potentially enhance the biocontrol efficiency when combined the attractants with nemacides. Methods: Bacteria producing volatiles with functions of nematode-attracting activities were isolated from 187 agricultural soil samples collected in 26 provinces of China with the method of double-Petri dishes. The phylogenetic diversity of these bacteria was characterized by RFLP-16S rRNA gene sequence analysis. The nematode-attracting volatiles of bacteria were detected using the SPME-GC/MS, and volatile compounds with attractive activity were determined by confirming with individual commercial compounds. Results: Among the 3800 bacteria isolated from the 187 soil samples, 196 isolates(5.16% of the total) showed attractive activity (AN)more than 30% to Panagrellus redivivus. Of the 196 isolates, 66 (1.74%) showed AN > or = 70%, 62 isolates (1.63%) showed AN between 50% and 70%, and 68 isolates (1.79%) showed AN less than 50%. Phylogenetic analysis revealed that the 196 bacteria were clustered into 5 groups: Bacilli, Gammaproteobacteria, Alphaproteobacteria, Sphingobacteria and Actinobacteria. But, Bacillus were the dominant, which covered 13 species. And 11 volatiles with nematode-attracting activity were determined, including benzaldehyde, 2-heptanone, benzyl benzoate, ethyl palmitate, (+)-longifolene, benzyl alcohol, p-anisaldehyde, vanatone, ethyl butyrate, isovanilin and d-alaninol. Conclusion: Some species of bacteria in agriculture soil can produce volatiles to attract nematodes.