TRNA-derived small RNA (tsRNA) is a novel regulatory small non-coding RNA and participates in diverse physiological and pathological processes. However, the presence of tsRNAs in exosome and their diagnostic potential remain unclear. In this study, we took advantage of small RNA-seq technology to profile exosomal tsRNAs from cell culture medium and plasma, and found ubiquitous presence of tsRNAs in exosome. To explore the potential value of tsRNA for cancer diagnosis, we compared exosomal tsRNA levels between liver cancer patients and healthy donors, revealing that tsRNAs were dramatically increased in plasma exosomes of liver cancer patients. Importantly, patients with liver cancer exhibited significantly higher levels of four tsRNAs (tRNA-ValTAC-3, tRNA-GlyTCC-5, tRNA-ValAAC-5 and tRNA-GluCTC-5) in plasma exosome, demonstrating that plasma exosomal tsRNA could serve as a novel diagnostic biomarker. Taken together, our results not only expand non-coding RNA species in exosome, but also highlight the potential of tsRNAs as a promising biomarker for cancer diagnosis.

Soil contaminated with the heavy metal Cadmium (Cd) is a widespread problem in many parts of the world. Based on metagenomic analysis, we investigated the functional potential and structural diversity of the microbial community in Cd-contaminated and non-contaminated soil samples and we explored the associated metabolic pathway network in cluster of orthologous groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The results showed that microorganisms in these soils were quite abundant, and many of them possessed numerous physiological functions. However, Cd-contamination has the potential to reduce the microbial diversity and further alter the community structure in the soil. Notably, function analysis of the crucial microorganisms (e. g. Proteobacteria, Sulfuricella and Thiobacillus) indicated that these bacteria and their corresponding physiological functions were important for the community to cope with Cd pollution. The COG annotation demonstrated that the predominant category was the microbial metabolism cluster in both soil samples, while the relative abundance of metabolic genes was increased in the Cd-contaminated soil. The KEGG annotation results exhibited that the non-contaminated soil had more genes, pathways, modules, orthologies and enzymes involved in metabolic pathways of microbial communities than the Cd-contaminated soil. The relative abundance of some dominant KEGG pathways increased in the Cd contaminated soil, and they were mostly enriched to the metabolism, biosynthesis and degradation of amino acids, fatty acids and nucleotides, which was related to Cd tolerance of the microorganisms. Cd-contamination can decrease the taxonomic species of microbes in soil and change the soil microbial composition. The functional pathways involved in the soil change with microbial structure variation, many of which are related to the heavy metal tolerance of soil microbes. The Cd-contaminated soil microbes is a potential resource for exploring cadmium resistant or tolerant bacteria.

Oncogenic fusion gene Echinoderm Microtubule-associated protein-Like 4-Anaplastic Lymphoma Kinase (EML4-ALK) contributes to tumorigenesis of a subset of non-small cell lung cancer (NSCLC). Recently, we demonstrated that F-circEA-4a, a tumor-promoting circular RNA (circRNA) generated from the back-splicing of EML4-ALK variant 3b (v3b), is a novel liquid biopsy biomarker for NSCLC. However, circRNAs produced from EML4-ALK gene and their roles in NSCLC are not well-characterized. Here, we identify another EML4-ALK-v3b-derived circRNA, F-circEA-2a, harboring “AA” (rather than “AAAA” in F-circEA-4a) motif at the junction site. F-circEA-2a mainly locates in the cytoplasm and promotes cell migration and invasion, but has little effect on cell proliferation. Moreover, F-circEA-2a exists in tumor, but not in the plasma of NSCLC patients with EML4-ALK fusion gene, further supporting the significant diagnostic value of F-circEA-4a for EML4-ALK-positive NSCLC. This work finds a novel oncogenic circRNA generated from EML4-ALK fusion gene, highlighting the pivotal role of circRNA in EML4-ALK-positive NSCLC development.

Monovalent DNA–gold nanoparticle (mDNA–AuNP) conjugates hold great promise for widespread applications, especially the construction of well-defined, molecule-like nanosystems. Previously reported methods all rely on the use of thiolated DNA to functionalize AuNPs, resulting in relatively low yields. Here, we report a facile method to rapidly prepare mDNA–AuNPs using a poly-adenine (polyA)-mediated approach. As polyA can selectively bind to AuNPs with high controllability of the surface density of DNA, we can use a DNA strand with a sufficiently long polyA to wrap around the surface of an individual AuNP, preventing further the adsorption of additional strands. Based on this observation, we obtained mDNA–AuNPs with a nearly quantitative yield of ~90% using 80 As, as confirmed by both gel electrophoresis and transmission electron microscope observation. The yields of mDNA–AuNPs were insensitive to the stoichiometric ratio between DNA and AuNPs, suggesting the click chemistry-like nature of this polyA-mediated reaction. mDNA–AuNPs exhibited rapid kinetics and high efficiency for sequence-specific hybridization. More importantly, we demonstrated that AuNPs of fixed valences could form well-defined heterogenous oligomeric nanostructures with precise, atom-like control.