Delayed full opening of bumped switchable molecular probe enables repeated generation of target analogues for mix-to-signaling determination of microRNAs
SENSORS AND ACTUATORS B-CHEMICAL
Authors: Ma, Xiaoming; He, Shan; Zhang, Huifang; Li, Xun; Xue, Jun; Fan, Xiaolin; Lu, Yusheng; Chen, Yiting; Zhang, Yanjie; Xu, Jianguo
Herein, we have designed a unique oligonucleotide probe named as bumped switchable molecular probe (BS-MB) and employ it to ultrasensitive detection of miRNA-21. The uniqueness is that the bumped portion renders the BS-MB great design flexibility and divides its long stem into two short stems so that it can play the roles of recognition unit, reporting unit, and polymerization primer and template simultaneously. The opening of BS-MB requires a delayed reaction, allowing the system a better-suppressed background without miRNA-21. In contrast, the introduction of miRNA-21 delayed the full opening of BS-MB, inducing a concurrent three-stage amplification for consuming lots of BS-MBs in one amplification event. During the amplification, lots of target analogues of extended miRNA-21 (E-miRNA-21) and cleavaged miRNA-21 (C-miRNA-21) that can be reused as miRNA-21 to cause further fluorescence enhancement are repeatedly generated. The system retains the simplicity (one oligonucleotide probe) and simplifies the detection procedure (one-step detection). Its mix-to-signaling and oneto-many amplification behaviors are superior to conventional MB based amplification, exhibiting a wide linear response and a low detection limit of 8.1 fM. High specificity against even one-base mutation, desirable recovery rates for testing miRNA-spiked serum samples, and well-defined accuracy for classifying clinically related samples are also demonstrated.
Exposure of lead on intestinal structural integrity and the diversity of gut microbiota of common carp
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY
Authors: Zhang, Yue; Zhang, Peijun; Shang, Xinchi; Lu, Yuting; Li, Yuehong
Lead is an environmental toxicant that has toxicity effect to the health of aquatic organisms. Gut microbiota has been reported to be closely related to human health. The aim of this study was to investigate the effects of lead exposure on the composition of gut microbiota. The composition of gut microbiota alteration was detected by 16S rRNA gene sequencing, following a 42-day exposure of lead (1 mg/L). The results showed that compared with the normal control group, the carp of lead group showed severe intestinal tissues injury and decreased Zona Occludens 1 (ZO-1) and occludin expression. The production of LPS in serum was increased by the treatment of lead exposure. Our results showed gut bacterial diversity in lead-treated common carp was lower than the control group. At the phylum level, the abundance of Bacteroidetes (LPS producing bacteria) and Fusobacteria in lead-treated carp were much higher than the control carp. And the abundance of Actinobacteria decreased by lead exposure. At the genus level, we found the abundance of Bacteroides (LPS producing bacteria) and Plesiomonas (an important pathogenic bacteria), increased significantly by lead exposure. And the abundance of Akkermansia, a critical probiotics, was markedly inhibited by lead exposure. In conclusion, this study indicated exposure of carp to lead causes gut microbiota alterations and intestinal structural integrity destruction.