RESUMEN
Diospyros (Ebenaceae) is a widely distributed genus of trees and shrubs from pantropical to temperate regions, with numerous species valued for their fruits (persimmons), timber, and medicinal values. However, information regarding their plastomes and chloroplast evolution is scarce. The present study performed comparative genomic and evolutionary analyses on plastomes of 45 accepted Diospyros species, including three newly sequenced ones. Our study showed a highly conserved genomic structure across the Diospyros species, with 135-136 encoding genes, including 89 protein-coding genes, 1-2 pseudogenes (Ψycf1 for all, Ψrps19 for a few), 37 tRNA genes and 8 rRNA genes. Comparative analysis of Diospyros identified three intergenic regions (ccsA-ndhD, rps16-psbK and petA-psbJ) and five genes (rpl33, rpl22, petL, psaC and rps15) as the mutational hotspots in these species. Phylogenomic analysis identified the phylogenetic position of three newly sequenced ones and well supported a monophylogenetic (sub)temperate taxa and four clades in the pantropical taxa. The analysis codon usage identified 30 codons with relative synonymous codon usage (RSCU) values >1 and 29 codons ending with A and U bases. A total of three codons (UUA, GCU, and AGA) with highest RSCU values were identified as the optimal codons. Effective number of codons (ENC)-plot indicated the significant role of mutational pressure in shaping codon usage, while most protein-coding genes in Diospyros experienced relaxed purifying selection (d N/d S < 1). Additionally, the psbH gene showed positive selection (d N/d S > 1) in the (sub)temperate species. Thus, the results provide a meaningful foundation for further elaborating Diospyros's genetic architecture and taxonomy, enriching genetic diversity and conserving genetic resources.
RESUMEN
The genus Broussonetia (Moraceae) is comprised of three non-hybrid recognized species that all produce high quality fiber essential in the development of papermaking and barkcloth-making technology. In addition, these species also have medicinal value in several countries. Despite their important economical, medicinal, and ecological values, the complete mitogenome of Broussonetia has not been reported and investigated, which would greatly facilitate molecular phylogenetics, species identification and understanding evolutionary processes. Here, we assembled the first-reported three complete Broussonetia (B. papyrifera, B. kaempferi, and B. monoica) mitochondrial genomes (mitogenome) based on a hybrid strategy using Illumina and Oxford Nanopore Technology sequencing data, and performed comprehensive comparisons in terms of their structure, gene content, synteny, intercellular gene transfer, phylogeny, and RNA editing. Our results showed their huge heterogeneities among the three species. Interestingly, the mitogenomes of B. monoica and B. papyrifera consisted of a single circular structure, whereas the B. kaempferi mitogenome was unique and consisted of a double circular structure. Gene content was consistent except for a few transfer RNA (tRNA) genes. The Broussonetia spp. mitogenomes had high sequence conservation but B. monoica with B. kaempferi contained more synteny blocks and were more related, a finding that was well-supported in organellar phylogeny. Fragments that had been transferred between mitogenomes were detected at plastome hotspots that had integrated under potential mediation of tRNA genes. In addition, RNA editing sites showed great differences in abundance, type, location and efficiency among species and tissues. The availability of these complete gap-free mitogenomes of Broussonetia spp. will provide a valuable genetic resource for evolutionary research and understanding the communications between the two organelle genomes.
RESUMEN
The objective of this study is to prepare zein/starch sodium octenyl succinate composite nanoparticles (ZSPs) via anti-solvent precipitation technology and characterize their colloidal properties. The effects of polar solvents, ultrasonic treatment time, and concentrations of starch sodium octenyl succinate were investigated. We measured the particle size distribution, hydrophobicity, and apparent structures of the composite nanoparticles. Ultrasonic treatment time (0-25 min) was found to play an important role in composite nanoparticle formation. The ZSP nanoparticles were with an average particle size in the range of 70 to 110 nm. When the ultrasonic treatment time exceeds 25 min, ZSPs became macroscopic particles. The fluorescence spectrum and three-phase contact angle indicated that ZSPs presented hydrophilicity with largest three-phase contact angle, which was 65.1°. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that hydrophilic SSOS absorbed on the surface of zein nanoparticles via Van der Waals to improve their water solubility. The changes in solvent polarity and zein self-assembly are considered to be the main driving force for composite nanoparticles conformational transitions from α-helix to ß-sheet. Differential scanning calorimetry analysis indicated that ethanol combined ultrasonic treatment (10 min) was beneficial to enhance the thermal stability of composite nanoparticles, causing the highest Tg of 153.6°C. This work aims to provide a practical reference for formulating delivery systems using bioactive compounds containing zein as a carrier biopolymer. PRACTICAL APPLICATION: This work aims to provide a practical reference for formulating encapsulants for food and other bioactive compounds containing zein as a carrier biopolymer. Zein/starch sodium octenyl succinate composite nanoparticles formulated in this study provide novel stabilizers for emulsification systems or carriers of bioactive substances that can enhance the nutritional value, taste, or shelf life of foods.