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31.
Replication slippage may cause parallel evolution in the secondary structures of mitochondrial transfer RNAs 总被引:9,自引:4,他引:5
Presence of the dihydrouridine (D) stem in the mitochondrial cysteine tRNA
is unusually variable among lepidosaurian reptiles. Phylogenetic and
comparative analyses of cysteine tRNA gene sequences identify eight
parallel losses of the D-stem, resulting in D-arm replacement loops.
Sampling within the monophyletic Acrodonta provides no evidence for
reversal. Slipped-strand mispairing of noncontiguous repeated sequences
during replication or direct replication slippage can explain repeats
observed within cysteine tRNAs that contain a D-arm replacement loop. These
two mechanisms involving replication slippage can account for the loss of
the cysteine tRNA D-stem in several lepidosaurian lineages, and may
represent general mechanisms by which the secondary structures of
mitochondrial tRNAs are altered.
相似文献
32.
Chinthaka Kaluthota Benjamin E. Brinkman Ednei B. dos Santos Drew Rendall 《Proceedings. Biological sciences / The Royal Society》2016,283(1824)
There is growing interest in latitudinal effects on animal behaviour and life history. One recent focus is on birdsong, which is hypothesized to be more elaborated or complex in the north temperate zone compared with the tropics. Current evidence is mixed and based on cross-species comparisons, or single species with restricted distributions. We circumvent these limitations using a transcontinental sample of 358 songs from house wrens (Troglodytes aedon) at 281 locations spanning more than 100° of latitude (52° N–55° S) across the Americas. We found a significant latitudinal gradient in several basic elements of song performance and complexity between north temperate and tropical populations. Furthermore, we document convergence in song patterns between populations at higher latitudes in the Northern and Southern Hemispheres. Effects were strongest for the number of elements in a song, and the rate of element production, both increasing towards the poles, with similar but weaker effects for other song dimensions (e.g. number of unique elements, trills and trill rate). We consider possible causes related to variable habitats and morphology, concluding that the shorter breeding seasons at higher latitudes in both hemispheres may favour greater song elaboration to mediate territory competition and mate choice. 相似文献
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Florian Hahne Nolwenn LeMeur Ryan R Brinkman Byron Ellis Perry Haaland Deepayan Sarkar Josef Spidlen Errol Strain Robert Gentleman 《BMC bioinformatics》2009,10(1):106-8
Background
Recent advances in automation technologies have enabled the use of flow cytometry for high throughput screening, generating large complex data sets often in clinical trials or drug discovery settings. However, data management and data analysis methods have not advanced sufficiently far from the initial small-scale studies to support modeling in the presence of multiple covariates. 相似文献36.
The diageotropica mutation alters auxin induction of a subset of the Aux/IAA gene family in tomato 总被引:5,自引:0,他引:5
The diageotropica (dgt) mutation has been proposed to affect either auxin perception or responsiveness in tomato plants. It has previously been demonstrated that the expression of one member of the Aux/IAA family of auxin-regulated genes is reduced in dgt plants. Here, we report the cloning of ten new members of the tomato Aux/IAA family by PCR amplification based on conserved protein domains. All of the gene family members except one (LeIAA7) are expressed in etiolated tomato seedlings, although they demonstrate tissue specificity (e.g. increased expression in hypocotyls vs. roots) within the seedling. The wild-type auxin-response characteristics of the expression of these tomato LeIAA genes are similar to those previously described for Aux/IAA family members in Arabidopsis. In dgt seedlings, auxin stimulation of gene expression was reduced in only a subset of LeIAA genes (LeIAA5, 8, 10, and 11), with the greatest reduction associated with those genes with the strongest wild-type response to auxin. The remaining LeIAA genes tested exhibited essentially the same induction levels in response to the hormone in both dgt and wild-type hypocotyls. These results confirm that dgt plants can perceive auxin and suggest that a specific step in early auxin signal transduction is disrupted by the dgt mutation. 相似文献
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Marcelo H Ratto Louis TJ Delbaere Yvonne A Leduc Roger A Pierson Gregg P Adams 《Reproductive biology and endocrinology : RB&E》2011,9(1):24
Background
The objective of the present study was to isolate and purify the protein fraction(s) of llama seminal plasma responsible for the ovulation-inducing effect of the ejaculate. 相似文献39.
Firooznia F Cheung AW Brinkman J Grimsby J Gubler ML Hamid R Marcopulos N Ramsey G Tan J Wen Y Sarabu R 《Bioorganic & medicinal chemistry letters》2011,21(7):1933-1936
The highly potent but modestly selective N-(2-amino-4-methoxy-benzothiazol-7-yl)-N-ethyl-acetamide derivative 2 was selected as the starting point for the design of novel selective A2B antagonists, due to its excellent potency, and good drug-like properties. A series of compounds containing nonaromatic amides or ureas of five- or six-membered rings, and also bearing an m-trifluoromethyl-phenyl group (shown to impart superior potency) was prepared and evaluated for their selectivity against the A2A and A1 receptors. This work resulted in the identification of compound 30, with excellent potency and high selectivity against both A2A and A1 receptors. 相似文献
40.
Age-related augmentation of phosphorylase b kinase in hepatic tissue from the glycogen-storage-disease (gsd/gsd) rat. 下载免费PDF全文
D G Clark S D Neville M Brinkman P V Nelson R J Illman A Guthberlet W D Haynes 《The Biochemical journal》1986,238(3):811-816
The effects of food deprivation on body weight, liver weight, hepatic glycogen content, glycogenolytic enzymes and blood metabolites were compared in young and old phosphorylase b kinase-deficient (gsd/gsd) rats. Although the concentration of glycogen in liver from 9-week-old female gsd/gsd rats (730 mumol of glucose equivalents/g wet wt.) was increased by 7-8% during starvation, total hepatic glycogen was decreased by 12% after 24 h without food. In 12-month-old male gsd/gsd rats the concentration of liver glycogen (585 mumol of glucose equiv./g wet wt.) was decreased by 16% and total hepatic glycogen by nearly 40% after food deprivation for 24 h. Phosphorylase b kinase and phosphorylase a were present at approx. 10% of the control activities in 9-week-old gsd/gsd rats, but both enzyme activities were increased more than 3-fold in 12-month-old affected rodents. It is concluded that the age-related ability to mobilize hepatic glycogen appears to result from the augmentation of phosphorylase b kinase during maturation of the gsd/gsd rat. 相似文献