RESUMEN
This study aimed at exploring microalgal heterogeneity from fresh water samples collected from inland water bodies in the heavily built city of Singapore. Culturable pure isolates (n = 94) were subject to an in-house microalgal DNA extraction method and LSU rDNA sequencing. Isolates were analysed for their predominance and distribution. A total of 17 different algal genera were identified (H = 2.8, EH = 0.6), of which Scenedesmus spp. and Chlorella spp. constituted 27.5% and 21.3% of isolates respectively, followed by Micractinium spp. (18.8%) and Chlamydomonas spp. (12.5%). We also report 16 new microalgal strains from this region. The data is important from an ecological and biotechnological perspective.
Asunto(s)
Medios de Cultivo/metabolismo , Agua Dulce/química , Microalgas/genética , Biomasa , Chlamydomonas/genética , Chlorella/genética , ADN Ribosómico/genética , Scenedesmus/genética , SingapurRESUMEN
The repression of telomerase activity during cellular differentiation promotes replicative aging and functions as a physiological barrier for tumorigenesis in long-lived mammals, including humans. However, the underlying mechanisms remain largely unclear. Here we describe how miR-615-3p represses hTERT expression. mir-615-3p is located in an intron of the HOXC5 gene, a member of the highly conserved homeobox family of transcription factors controlling embryogenesis and development. Unexpectedly, we found that HoxC5 also represses hTERT expression by disrupting the long-range interaction between hTERT promoter and its distal enhancer. The 3'UTR of hTERT and its upstream enhancer region are well conserved in long-lived primates. Both mir-615-3p and HOXC5 are activated upon differentiation, which constitute a feed-forward loop that coordinates transcriptional and post-transcriptional repression of hTERT during cellular differentiation. Deregulation of HOXC5 and mir-615-3p expression may contribute to the activation of hTERT in human cancers.