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Apurinic/apyrimidinic endonuclease 1 (APE1) exonuclease plays a vital proofreading role in the base excision repair pathway by removing 3’end group, including oxidatively damaged DNA bases, chain terminating nucleotide analog drugs, terminal blocking groups and mismatched bases. Herein, a simple and real time fluorometric method was developed for detecting APE1 exonuclease activity using molecular beacon as substrate. Experimental results demonstrated that the detection limit of this method was 0.01 U/μL for APE1, and the Km value was (0.27 ± 0.10) μmol/L. Moreover, the method was used to screen antibiotics and the results showed that streptomycin sulfate and gentamycin sulfate had a significant inhibitory effect on APE1 exonuclease activity in a concentration-dependent manner. Meanwhile, the assay was used for investigating the inhibitory effects of heavy metal ions on APE1 exonuclease activity. Finally, the method was further used to monitor the effect of heavy metal ions treatment of the APE1 exonuclease activity of ramie, and the results indicated that APE1 exonuclease activity was inhibited in a concentration-dependent manner after treatment with Pb2+ and Cd2+, which was consistent with heavy metal ions assay in vitro. In summary, this method provided an alternative tool for the biochemical analysis for APE1 exonuclease activity, which was hopeful for the assessment for heavy metal ions adsorption according to the enzymatic activity change in phytoremediation.

In this paper, we present the transcriptome profiles of the A. venetum L. by RNA-Seq approach. A total of 6.57 Gb raw data were obtained, and 52,983 unigenes with an average length of 1009 bp and N50 of 1632 bp were annotated with the 7 databases. The unigenes annotated to KEGG database were divided into 21 categories from 6 main groups. Among these, 4952 (22.21%) unigenes were clustered to “Global and overview maps”, and 1834 (8.23%) unigenes were clustered to “Carbohydrate metabolism”. In addition, 6340 unigenes containing 7579 SSRs were identified and the mononucleotide, dinucleotide, trinucleotide motifs were the most common motif type (95.59%), accounting for 39.62%, 36.02%, and 19.95%, respectively.

Ramie (Boehmeria nivea (L.) Gaudich) is widely used in the manufacture of garments and industrial fabrics. In the present study, 1151 ramie germplasm resources from 13 regions within China, Brazil, Indonesia, India, and Cuba were analyzed for genetic diversity and population structure using 23 simple sequence repeat (SSR) markers and three phenotypic markers to provide baseline information for ramie’s breeding and conservation plans. Overall, 117 loci were identified and Shannon’s diversity index ranged from 0.3201 to 1.6773 (average, 0.8272). The polymorphism information content varied from 0.1578 to 0.7603 (average, 0.5017), expected heterozygosity from 0.1694 to 0.7815 (average, 0.5282), and genetic diversity from 0.1722 to 0.7884 (average, 0.5228). Genetic diversity was higher in Sichuan, Yunnan, and Guizhou than in the other regions studied. Cluster analysis based on unweighted pair group method with arithmetic mean and genetic distance revealed marked differences between domestic (Chinese) and foreign (other regions) germplasm resources. Population structure analysis also evidenced two groups. Genetic diversity was higher in wild than in domesticated germplasms. Overall, results obtained here will be useful for selecting parents for breeding and performing association analyses in ramie.