Insights into the evolution of mammalian telomerase: Platypus TERT shares similarities with genes of birds and other reptiles and localizes on sex chromosomes

Background The TERT gene encodes the catalytic subunit of the telomerase complex and is responsible for maintaining telomere length. Vertebrate telomerase has been studied in eutherian mammals, fish, and the chicken, but less attention has been paid to other vertebrates. The platypus occupies an important evolutionary position, providing unique insight into the evolution of mammalian genes. We report the cloning of a platypus TERT (OanTERT) ortholog, and provide a comparison with genes of other vertebrates. Results The OanTERT encodes a protein with a high sequence similarity to marsupial TERT and avian TERT. Like the TERT of sauropsids and marsupials, as well as that of sharks and echinoderms, OanTERT contains extended variable linkers in the N-terminal region suggesting that they were present already in basal vertebrates and lost independently in rayfinned fish and eutherian mammals. Several alternatively spliced OanTERT variants structurally similar to avian TERT variants were identified. Telomerase activity is expressed in all platypus tissues like that of cold-blooded animals and murine rodents. OanTERT was localized on pseudoautosomal regions of sex chromosomes X3/Y2, expanding the homology between human chromosome 5 and platypus sex chromosomes. Synteny analysis suggests that TERT co-localized with sex-linked genes in the last common mammalian ancestor. Interestingly, female platypuses express higher levels of telomerase in heart and liver tissues than do males. Conclusions OanTERT shares many features with TERT of the reptilian outgroup, suggesting that OanTERT represents the ancestral mammalian TERT. Features specific to TERT of eutherian mammals have, therefore, evolved more recently after the divergence of monotremes.Radmila Hrdličková, Jiří Nehyba, Shu Ly Lim, Frank Grützner, Henry R Bose J

Quality of Barley From 2001 Crop - Brewery Section.

In this work, analytical parameters and sensorial properties of 11% beers brewed from 2001 crop barleys were assessed. For semipilot Czech technology beer brewing, 6 samples of barleys taken from Bohemian and Moravian regions were malted. In most cases, analytical parameters were better than the ones in 2000. The prepared malts show a low protein content, low soluble nitrogen and β-glucanes, have good values of DFLU extract difference, a low pH value of hopped wort (5,5 in average), a low content of diacetyl in beer (less than 10 mg/l) and show a relatively higher content of dimethyl sulfide precursors. Enzymatic capability of the malts was assessed as very good. When comparing with previous years, especially the clarity during run off of wort was worse. All beers showed an excellent filterability. The sensorial properties of brewed beers can be assessed as good to average. Overall, it can be said the barleys can be assessed as of highest quality in the course of the last three years. The comparison of the samples from various regions shows a better equability than in previous years.In this work, analytical parameters and sensorial properties of 11% beers brewed from 2001 crop barleys were assessed. For semipilot Czech technology beer brewing, 6 samples of barleys taken from Bohemian and Moravian regions were malted. In most cases, analytical parameters were better than the ones in 2000. The prepared malts show a low protein content, low soluble nitrogen and β-glucanes, have good values of DFLU extract difference, a low pH value of hopped wort (5,5 in average), a low content of diacetyl in beer (less than 10 mg/l) and show a relatively higher content of dimethyl sulfide precursors. Enzymatic capability of the malts was assessed as very good. When comparing with previous years, especially the clarity during run off of wort was worse. All beers showed an excellent filterability. The sensorial properties of brewed beers can be assessed as good to average. Overall, it can be said the barleys can be assessed as of highest quality in the course of the last three years. The comparison of the samples from various regions shows a better equability than in previous years

P–T–t–D record of crustal-scale horizontal flow and magma-assisted doming in the SW Mongolian Altai.

International audienc