The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points.

Since comprehensive analysis of the mammalian genome revealed that the majority of genomic products are transcribed in long non‐coding RNA (lncRNA), increasing attention has been paid to these transcripts. The applied next‐generation sequencing technologies have provided accumulating evidence of dysregulated lncRNA in cancer. The implication of this finding can be seen in many forms and at multiple levels. With impacts ranging from integrating chromatin remodeling complexes to regulating transcription and post‐transcriptional processes, aberrant expression of lncRNA may have repercussions in cell proliferation, tumor progression or metastasis. lncRNA may act as enhancers, scaffolds or decoys by physically interacting with other RNA species or proteins, resulting in a direct impact on cell signaling cascades. Even though their functional classification is well‐established in the context of cancer, clearer characterization in terms of their phenotypic outputs is needed to optimize and identify suitable candidates that enable the development of new therapeutic strategies and the design of novel diagnostic approaches. The present article aims to outline different cancer‐associated lncRNA according to their contribution to tumor suppression or tumor promotion based on their most current functional annotations.

No abstract

We determined the 16s rRNA sequences of the type strains of Streptococcus mitis and Streptococcus gordonii and calculated the phylogenetic distances between those organisms and other members of the genus Streptococcus. The viridans group streptococci were separated into five phylogenetic groups; we named these groups the anginosus group, the mitis group, the salivarius group, the bovis group, and the mutans group. S. rnitis and S. gordonii clustered in the mitis group together with Streptococcus pneumoniae, Streptococcus oralis, Streptococcus sunguis, and Streptococcusparasanguis at levels of sequence homology of more than 96%. Within this group, S. mitis, S. om&, and S. pneumoniae exhibited more than 9% sequence homology with each other, although the DNA-DNA similarity values for their total chromosome DNAs were less than 60%.In the past 10 years, several new members have been added to the viridans streptococcus group (3, 11, 18-20). Streptococcus oralis, Streptococcus parasanguis, and Streptococcus gordonii are the major new species that have been described. These organisms are often isolated from human clinical specimens and thus are clinically important species. However, workers at clinical laboratories have found that it is difficult to identify viridans group streptococci because of the lack of decisive phenotypic characteristics.Some of the confusion concerning identification of these bacteria came from the type strain of Streptococcus mitis, strain NCTC 3165. This type strain had traits different from the traits described for the species. Therefore, Coykendall et al. ( 5 ) proposed that S. rnitis NCTC 3165 should be rejected as the type strain, and in Opinion 66 (10) strain NCTC 12261 was designated the neotype strain of S. rnitis. The rejected type strain is now identified as an S. gordonii strain, and we have confirmed this identification by DNA-DNA hybridization (unpublished data). In a previous study, we developed quantitative microplate DNA-DNA hybridization methods to identify streptococci (6, 7) and found that many strains which were identified as S. mitis, S. oralis, and Streptococcus sanguis by phenotypic methods were misidentified. Another problem arose when we applied quantitative DNA-DNA hybridization methods to the identification of viridans group streptococci. Many strains identified biochemically as S. mitis were difficult to differentiate from S. oralis and Streptococcus pneurnoniae even by the hybridization method because clinical strains NJ- 0.01 FIG. 1. Phylogenetic relationships among 34Streptococcus species. Distances were calculated by the neighbor-joining (NJ) method. S. pleomorphus was located far from other species, so its distance is indicated with an ellipsis; its true distance from the junction was 0.16944.

Volume 45, no. 2, p. 321, column 1, line 38: "straight-chain unsaturated and monosaturated" should read "straight-chain Page 325, column 2, lines 22 and 23: "Straight-chain unsaturated and monosaturated" should read "Straight-chain saturated and saturated and monounsaturated." monounsaturated."