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41.
Infection with the human gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi''s sarcoma-associated herpesvirus (KSHV), is associated with several cancers. During lytic replication of herpesviruses, viral genes are expressed in an ordered cascade. However, the mechanism by which late gene expression is regulated has not been well characterized in gammaherpesviruses. In this study, we have investigated the cis element that mediates late gene expression during de novo lytic infection with murine gammaherpesvirus 68 (MHV-68). A reporter system was established and used to assess the activity of viral late gene promoters upon infection with MHV-68. It was found that the viral origin of lytic replication, orilyt, must be on the reporter plasmid to support activation of the late gene promoter. Furthermore, the DNA sequence required for the activation of late gene promoters was mapped to a core element containing a distinct TATT box and its neighboring sequences. The critical nucleotides of the TATT box region were determined by systematic mutagenesis in the reporter system, and the significance of these nucleotides was confirmed in the context of the viral genome. In addition, EBV and KSHV late gene core promoters could be activated by MHV-68 lytic replication, indicating that the mechanisms controlling late gene expression are conserved among gammaherpesviruses. Therefore, our results on MHV-68 establish a solid foundation for mechanistic studies of late gene regulation.  相似文献   
42.
Isothiocyanates (ITCs) are one of several hydrolysis products of glucosinolates, plant secondary metabolites that are substrates for the thioglucohydrolase myrosinase. Recent pursuits toward the development of synthetic non-natural ITCs have consequently led to an exploration of generating these compounds from non-natural glucosinolate precursors. Evaluation of the myrosinase-dependent conversion of select non-natural glucosinolates to non-natural ITCs cannot be accomplished using established ultraviolet–visible (UV–Vis) spectroscopic methods. To overcome this limitation, an alternative high-performance liquid chromatography (HPLC)-based analytical approach was developed where initial reaction velocities were generated from nonlinear reaction progress curves. Validation of this HPLC method was accomplished through parallel evaluation of three glucosinolates with UV–Vis methodology. The results of this study demonstrate that kinetic data are consistent between both analytical methods and that the tested glucosinolates respond similarly to both Michaelis–Menten and specific activity analyses. Consequently, this work resulted in the complete kinetic characterization of three glucosinolates with Sinapis alba myrosinase, with results that were consistent with previous reports.  相似文献   
43.
Caesalpinia platyloba was evaluated as an alternative for the retention of atmospheric carbon and as a feasible and viable economic activity in terms of income for tropical deciduous forest (TDF) peasants in the carbon markets. A total of 110 trees of C. platyloba from plantations and a TDF in the Northwest of Mexico were sampled. Growth (increase in height, diameter, and volume curves) was adjusted to assess their growth. Growth of individuals (height, diameter at breast height [DBH], age, and tree crown cover) was recorded. The Schumacher model (H = β0eβ1E-1), by means of the guided curve method, was used to adjust growth models. Information analysis was made through the non-linear procedure with the multivariate secant or false position (DUD) method using the SAS software. Growth and increase models revealed acceptable adjustments (pseudo R2>0.8). C. platyloba reaches >8m of height with 12cm in diameter and 550cm3 of volume, presenting the highest increase at 11 years considered as basal age. Highest significant density of wood was in good quality sites (0.80g•cm-3), with a carbon content (average of 99.15tC•ha-1) at the highest density of 2500 trees•ha-1 (without thinning). Average incomes of US$483.33tC•ha-1 are expected. The profitability values (NPW = US$81,646.65, IRR = 472%, and B/C = 0.82) for C. platyloba make its cultivation a viable and profitable activity, considering a management scheme of the income derived from wood selling and from carbon credits.  相似文献   
44.
ObjectivesTo identify, appraise and summarize existing knowledge and knowledge gaps in practice-relevant questions in pediatric dentistry.MethodsA systematic mapping of systematic reviews was undertaken for domains considered important in daily clinical practice. The literature search covered questions in the following domains: behavior management problems/dental anxiety; caries risk assessment and caries detection including radiographic technologies; prevention and non-operative treatment of caries in primary and young permanent teeth; operative treatment of caries in primary and young permanent teeth; prevention and treatment of periodontal disease; management of tooth developmental and mineralization disturbances; prevention and treatment of oral conditions in children with chronic diseases/developmental disturbances/obesity; diagnosis, prevention and treatment of dental erosion and tooth wear; treatment of traumatic injuries in primary and young permanent teeth and cost-effectiveness of these interventions. Abstracts and full text reviews were assessed independently by two reviewers and any differences were solved by consensus. AMSTAR was used to assess the risk of bias of each included systematic review. Reviews judged as having a low or moderate risk of bias were used to formulate existing knowledge and knowledge gaps.ResultsOut of 81 systematic reviews meeting the inclusion criteria, 38 were judged to have a low or moderate risk of bias. Half of them concerned caries prevention. The quality of evidence was high for a caries-preventive effect of daily use of fluoride toothpaste and moderate for fissure sealing with resin-based materials. For the rest the quality of evidence for the effects of interventions was low or very low.ConclusionThere is an urgent need for primary clinical research of good quality in most clinically-relevant domains in pediatric dentistry.  相似文献   
45.
Heat-Shock Protein 70 Levels in Temperature-Stressed Mung Bean Shoots   总被引:1,自引:0,他引:1  
Heat-shock protein 70 accumulation was induced by both increasesand decreases in temperature. An upward temperature shift ofabout 15C or a downward shift of about 10C was needed forthe response. In each case the accumulation was significantwithin 2 h and complete within about 6 h. Heat-shocked tissuecontained two new HSP70 isotypes not seen in the control tissueor in the cold-shocked tissue. Key words: Heat-shock protein, heat stress, cold stress, mung bean  相似文献   
46.
John H. Burgess 《CMAJ》1993,148(2):234
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47.
P Kast  C Wehrli  H Hennecke 《FEBS letters》1991,293(1-2):160-163
Phenylalanyl-tRNA synthetase (PheRS; alpha 2 beta 2 subunit structure) is a member of class II of tRNA synthetases. We report here the genetic analysis of an Escherichia coli mutant strain which is auxotrophic for phenylalanine because it has a PheRS with a decreased affinity for phenylalanine. The mutant pheS gene encoding the PheRS alpha subunit was cloned and sequenced, and the deviation from the wild-type gene was found to result in a Gly191-to-Asp191 exchange. This alteration is located within motif 2, one of 3 conserved sequence motifs characteristic for class II aminoacyl-tRNA synthetases. Motif 2 may thus participate in the formation of the phenylalanine binding site in PheRS.  相似文献   
48.
The results of the investigations of radioactive contamination after the Chernobyl catastrophe and subsequent iodine prophylaxis on the thyroid gland function and morphology in Northeast Poland. The aim of the study was to determine whether kalium iodine in one dose during radioactive contamination in Poland limited the radioactive dose in the thyroid gland and if significant disadvantageous side-effects in the intrathyroid and extrathyroid occurred. Additionally during the studies we tried to determine if radioactive iodine contamination which occurred in the region of the Medical Academy in Bia?ystok caused an increase in thyroid disease. It is interesting to note the different results obtained after radioactive contamination with the results from the investigations in this same territory in 1983-1985. In 1983-1985, before the Chernobyl catastrophe, 6,921 persons in Northeast Poland were investigated. In 1986-1988, immediately after the disaster 4,010 persons were investigated. The main study according to grant No MZ-XVII was carried out in three provinces: Bia?ystok, Suwa?ki and Olsztyn. In this investigation 10,011 persons born before April 26, 1986 and after January 1, 1936 participated, 5,789 townspeople and 4,222 villagers, 3,987 children up to 16 years of age it the time of the disaster 1,973 boys and 2,009 girls; 6,024 adults 2,509 men and 3,516 women were drawn from a register. Committed doses to the thyroid in the investigated region were one of the highest in Poland and depended on age group and were depended on time of prophylaxis non proportional. Iodine prophylaxis was provided mainly with one dose of Lugol solution about 90%, 95% children and 30% adults took iodine. The majority of the population (53.3%-74%) were given iodine in April. From May 1st to 5th 23.0-43.4% received iodine, but after May 5th very few persons. Iodine was well tolerated, but Lugol Solution was better tolerated than other kinds of iodine. Only 241 (4.4%) cases had side effects, mainly vomiting (143), symptoms such as stomach ache, diarrhea, dyspnoe, skinrash etc. in lesser numbers. 12% (29 persons) were seen by a physician. In the investigated population were 200 pregnant women aged 19-40 years of which the majority (177) delivered full term healthy babies. Only 1 interrupted pregnancy and 7 had spontaneous abortion. Changes in the thyroid were noticed by 187 persons (2.3%-11.7%) most of which were enlargement of the thyroid, but only a few were confirmed by a physician. In the studied population from 1989 to 1990 over 30% of the population had struma.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
49.
The probable misfit between feet, particularly toes II–V, of 3.0-million-year-oldAustralopithecus afarensis from Hadar, Ethiopia, and the 3.5-million-year-old hominid footprints at Site G, Laetoli, Tanzania, casts doubt thatA. Afarensis made the Laetoli trails. We suggest that another species ofAustralopithecus or an anonymous genus of the Hominidae, with remarkably humanoid feet, walked at Laetoli. It would be imprudent to declare thatHomo was present at Laetoli 3.5 million years ago (my) because there is no evidence of brain expansion, advanced tool manufacture, or other non-locomotor hallmarks of the human condition at Site G.  相似文献   
50.
Identification of a polymorphism in human CD44   总被引:1,自引:0,他引:1       下载免费PDF全文
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