Archival storage in DNA is one of the most challenging themes in rapidly growing information technology. In addition, its practical applications are more difficult due to complicated data analysis, instability of long and linear DNA strands (>1000 nt), and other factors. In the present study, we have developed a simple and eminent DNA-based storage system in which small DNA rings are employed as memory units. Compared with previous approaches, this methodology has advantages of robustness, low cost, convenience and so on. In high density, Chinese language was directly stored in a pool of 76-nt-long single-stranded DNA rings (designated as “Info-Store”), in which each ring memorized the index number and five Chinese characters (or marks). During “Read-Out”, all the ssDNA rings in the pool were simultaneously amplified by hyper-branched rolling cycle amplification (HRCA), and their sequences were accurately determined by a portable MinION sequencer aided by a personal computer. Then, the original Chinese text was precisely and smoothly decoded by simple data analysis.

Vibrio parahaemolyticus (V. parahaemolyticus) is considered the most concerning pathogen for seafood. Like other pathogens in food samples, its gene detection suffers from a problem of background interference when isothermal detection methods are used. The sensitivity and specificity greatly decrease due to large amounts of background genome. Here we describe a novel isothermal detection technology based on target-cyclized rolling circle amplification combined with loop-mediated isothermal amplification (tRCA-lamp). By avoiding unexpected ligation, a short dynamic adapter is employed to increase the sensitivity of target cyclization in the presence of the background genome. At the amplification step, highly specific detection is obtained by linear RCA and simplified LAMP (only two primers are used). Furthermore, visual detection is easily realized with hydroxynaphthol blue (HNB). In the oyster samples, the tRCA-lamp approach can detect V. parahaemolyticus with a detection limit of 22 cfu/g with none necessary to enrich the bacteria and remove the host DNA. This method gets rid of the complicated primer design process and can be extended to the detection of other pathogens in food samples.

Thermus thermophilus DNA ligase (Tth DNA ligase) is widely employed for cloning, enzymatic synthesis, and molecular diagnostics at high temperatures (e.g., 65 °C). It has been long believed that the complementary ends must be very long (e.g., >30 bp) to place two DNA fragments nearby for the ligation. In the current study, the length of the complementary portion was systematically varied, and the ligation efficiency was evaluated using the high resolution melting (HRM) method. Unexpectedly, very short oligonucleotides (7–10 nt) were successfully ligated on the complementary overhang attached to a dsDNA at 70 °C. Furthermore, sticky ends with the overhang of only 4 nt long, available after scission with many restriction enzymes, were also efficiently ligated at 45–70 °C. The ligation yield for the 6-nt-long sticky ends was as high as 80%. It was concluded that Tth DNA ligase can be used as a unique tool for DNA manipulation that cannot be otherwise easily accomplished.

Novel cell-targeting ligand structures are constructed with a spikey core scaffold, where multiple copies of coiled-coil peptide nanorods are conjugated on the surface of a peptide nanosheet. Clustering of carbohydrate...