RESUMEN
The development of fluorescent probe for hydrazine (N2H4) detection has attracted much attention due to the important role of N2H4 plays in the fields of medicine, agriculture, biology and environments. In this paper, the optical properties and water solubility of two novel two-photon fluorescent molecular probes (Probe1 and Probe2) before and after the reaction with N2H4 are studied by using the density function theory. The results show that electronic distribution and transition dipole moment of the probes are obviously changed after the reaction with N2H4, thus the optical properties of the molecules are influenced and the detection of N2H4 are realized. In addition, photoinduced electron transfer processes for Probe1 and Probe2 in the presence of N2H4 are theoretically characterized, which explains the experimental observations from the microscopic mechanism. Special attention has been paid on the analysis of the two-photon absorption for the probes with the absence and presence of N2H4 by the response theory method. Both probes with good water solubility show large variation on the two-photon absorption cross section when reacts with N2H4. In particular, the two-photon absorption response of Probe2 is more obvious, so it possesses preferable two-photon fluorescence microscopic imaging ability. More importantly, the receptor effect on the sensing performances of the probes are demonstrated, providing a theoretical reference for the design and synthesis on more efficient two-photon fluorescence N2H4 probes. Our study provides necessary information on the response mechanism of the studied chemosensors and helps to establish the relationship between the structure and optical properties of two-photon fluorescence N2H4 probes.
RESUMEN
Melastoma malabathricum is an important medicinal and landscape plant that is globally distributed in temperate and subtropical regions. However, available genomic information for the entire Melastomataceae family is notably limited. In view of the application potential of floral parts in secondary metabolite extraction, we characterized for the first time the floral transcriptomes of two key M. malabathricum varieties, purple variety and white variety. Our transcriptome assembly generated 52,498 and 49,380 unigenes with an N50 of 1,906 and 1,929 bases for the purple and white varieties, respectively. Comparative analysis of two transcriptomes demonstrated that they are highly similar but also highlighted genes that are presumably lineage specific, which explains the phenotypes of each variety. Additionally, a shared transcriptional signature across the floral developmental stages was identified in both M. malabathricum varieties; this signature included pathways related to secondary metabolite synthesis, plant hormone signaling and production, energy homeostasis and nutrient assimilation pathways, and cellular proliferation. The expression levels of flavonoid accumulation and candidate flavonoid biosynthesis-related genes in M. malabathricum flower development stages validated the transcriptome findings. The transcriptome data presented in this study will serve as a valuable resource for future work on the exploitation of M. malabathricum and other related species. The gene expression dynamics during flower development will facilitate the discovery of lineage-specific genes associated with phenotypic characteristics and will elucidate the mechanism of the ontogeny of individual flower types.