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Prevention of translational frameshifting by the modified nucleoside 1-methylguanosine 总被引:15,自引:0,他引:15
The methylated nucleoside 1-methylguanosine (m1G) is present next to the 3' end of the anticodon (position 37) in all transfer RNAs (tRNAs) that read codons starting with C except in those tRNAs that read CAN codons. All of the three proline tRNA species, which read CCN codons in Salmonella typhimurium, have been sequenced and shown to contain m1G in position 37. A mutant of S. typhimurium that lacks m1G in its tRNA when grown at temperatures above 37 degrees C, has now been isolated. The mutation (trmD3) responsible for this methylation deficiency is in the structural gene (trmD) for the tRNA(m1G37)methyltransferase. Therefore, the three proline tRNAs in the trmD3 mutant have an unmodified guanosine at position 37. Furthermore, the trmD3 mutation also causes at least one of the tRNAPro species to frequently shift frame when C's are present successively in the message. Thus, m1G appears to prevent frameshifting. The data from eubacteria apply to both eukaryotes and archaebacteria. 相似文献
3.
Huawei Ji Jiahao Wen Baoming Du Ningxiao Sun Björn Berg Chunjiang Liu 《Annals of Forest Science》2018,75(2):59
Key message
Foliar phosphorus (P) resorption in Quercus variabilis Blume was significantly lower at a P-rich than at a P-deficient site. Moreover, P resorption strongly decreased, and nitrogen:phosphorus and carbon:phosphorus resorption ratios increased with soil P content. This demonstrates a strong link between foliar P resorption and P content in soils, and emphasizes the importance of P resorption in leaves of trees growing in soils with contrasted P content.Context
Subtropical ecosystems are generally characterized by P-deficient soils. However, P-rich soils develop in phosphate rock areas.Aims
We compared the patterns of nutrient resorption, in terms of ecological stoichiometry, for two sites naturally varying in soil P content.Methods
The resorption efficiency (percentage of a nutrient recovered from senescing leaves) and proficiency (level to which nutrient concentration is reduced in senesced leaves) of 12 elements were determined in two oak (Q. variabilis) populations growing at a P-rich or a P-deficient site in subtropical China.Results
P resorption efficiency dominated the intraspecific variation in nutrient resorption between the two sites. Q. variabilis exhibited a low P resorption at the P-rich site and a high P resorption at the P-deficient site. Both P resorption efficiency and proficiency strongly decreased with soil P content only and were positively related to the N:P and C:P ratios in green and senesced leaves. Moreover, resorption efficiency ratios of both N:P and C:P were positively associated with soil P.Conclusion
These results revealed a strong link between P resorption and P stoichiometry in response to a P deficiency in the soil, and a single- and limiting-element control pattern of P resorption. Hence, these results provide new insights into the role of P resorption in plant adaptations to geologic variations of P in the subtropics.4.
Maria Johansson Sabrina Dressel Emma Kvastegård Göran Ericsson Anke Fischer Bjørn P. Kaltenborn 《Human Dimensions of Wildlife》2016,21(2):158-168
European researchers from both the natural and social sciences show growing interest in studying interactions between society and wildlife. A wealth of theoretical frameworks, concepts, and methods are used, but an integration of perspectives is lacking. This research note summarizes results from two workshops that included 63 delegates from 25 European countries, as well as a follow-up survey of 41 respondents. Two main theoretical approaches to the study of human–wildlife interactions were identified. One approach focuses on the collective societal level relying on theories of governance, social representation, deliberative procedures, and commons theory. The other approach targets individuals or groups, and is based on theories such as the cognitive hierarchy, theory of reasoned action, and theory of planned behavior. Interdisciplinary collaboration is needed to identify the best options for wildlife conservation and management in a more politically integrated Europe. 相似文献
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Grete Hansen Aas Olaug Taran Skjerdal Iren Stoknes Ingebrigt Bjørkevoll 《Journal Of Aquatic Food Product Technology》2013,22(3-4):149-161
Different packaging conditions of salt-cured cod fillets were studied during 2-years chilled storage. Yield and quality of salt-cured Atlantic cod fillets packed in sealed polystyrene boxes or in traditional cardboard boxes were compared. After 4 months, yield decreased by approximately 10% and decreased further when packed in cardboard boxes. Lipid oxidation was low after 12 months, and no microbiological spoilage was registered. The total amount of bacteria in the fish reduced with storage time, independent of packaging. The reddish color of halophilic bacteria was detected after 7–8 weeks at 18°C, but not if packed with MAP. 相似文献
7.
Karlsson Anneli S. Lesch Michael Weihermüller Lutz Thiele Björn Disko Ulrich Hofmann Diana Vereecken Harry Spielvogel Sandra 《Journal of Soils and Sediments》2020,20(4):2067-2081
Journal of Soils and Sediments - Pesticide contamination of river waters is a global problem, and therefore, authorities regularly monitor the water quality status. Especially, flood events might... 相似文献
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Björnsdóttir S Axelsson M Eksell P Sigurdsson H Carlsten J 《Equine veterinary journal》2000,32(3):268-272
The prevalence of degenerative joint disease (DJD) in the distal tarsal joints and the relation between radiographic and clinical signs compatible with the disease were estimated in a population of Icelandic horses used for riding. The material consisted of 614 horses age 6-12 years (mean age = 7.9 years). Radiographs with 3 projections of each tarsus were made and a clinical examination, including palpation of the medial aspect of the distal tarsus and motion evaluation of the hindlimbs before and after a flexion test of the tarsus, was performed. Radiographic signs of DJD in the distal tarsal joints were found in 30.3% of the horses and the prevalence was strongly correlated with age. Hindlimb lameness before and after flexion test and palpation abnormalities were significantly associated with the radiographic findings. The lameness was usually mild and, in most cases, detectable only after the flexion test. The prevalence of lameness was not significantly correlated with age. Lameness could not be predicted by details of the radiographic findings. 相似文献
10.
Behavioral Abnormalities in Lagotto Romagnolo Dogs with a History of Benign Familial Juvenile Epilepsy: A Long‐Term Follow‐Up Study 下载免费PDF全文
T.S. Jokinen K. Tiira L. Metsähonkala E.H. Seppälä A. Hielm‐Björkman H. Lohi O. Laitinen‐Vapaavuori 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(4):1081-1087