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1.
Two new dehydrotriferulic acids were isolated from saponified maize bran insoluble fiber using Sephadex LH-20 chromatography followed by semi-preparative RP-HPLC. Based on UV-spectroscopy, mass spectroscopy and one- and two-dimensional NMR experiments, the structures were identified as 8-O-4,8-O-4-dehydrotriferulic acid and 8-8(cyclic),8-O-4-dehydrotriferulic acid. Which of the possible phenols in the initially formed 8-8-dehydrodiferulate was etherified by 4-O-8-coupling with ferulate has been unambiguously elucidated. The ferulate dehydrotrimers which give rise to these dehydrotriferulic acids following saponification are presumed, like the dehydrodiferulates, to cross-link polysaccharides. Neither dehydrotriferulic acid described here involves a 5-5-dehydrodiferulic acid unit; only the 5-5-dehydrodimer may be formed intramolecularly. However, whether dehydrotriferulates are capable of cross-linking more than two polysaccharide chains remains open. Although the levels of the isolated ferulate dehydrotrimers are lower than those of the ferulate dehydrodimers, the isolation now of three different dehydrotriferulates indicates that trimers contribute to a strong network cross-linking plant cell wall polysaccharides.  相似文献   

2.
Ratings of subjective sleepiness are often used in laboratory and field studies of sleep loss and shifted sleep hours. Some studies suggest that such ratings might fail to reflect sleepiness as shown in physiology or performance. One reason for this may be the influence of the context of the rating. Social interaction or physical activity may mask latent sleepiness. The present study attempted to approach this question. Nine subjects participated in a partial sleep-deprivation experiment (five days of 4 h of time in bed [TIB]), preceded by two baseline days (8 h TIB) and followed by three recovery days (8 h TIB). Sleepiness was self-rated on the Karolinska Sleepiness Scale (KSS; scores of 1-9) after a period of relaxation, after a reaction-time test, and after 30 min of free activities. The results showed a strong increase in subjective sleepiness during sleep restriction and a significant difference between conditions. Free activity reduced the self-rated subjective sleepiness by 1.1 KSS units compared to the level of sleepiness self-rated at the end of the reaction-time test. Thus, the results of this study indicate that the context of a sleepiness rating affects the outcome of the rating.  相似文献   

3.
Permethylated 6-C-diglycosyl-8-C-glycosylflavones and 6-C-glycosyl-8-C-diglycosylflavones gave well defined EIMS including the molecular peak and a fragmentation pattern characteristic of the 6-C-glycosyl residue. X″′-O-glycosides (8-C-disaccharides) are thus easily distinguished from X″-O-glycosides (6-C-disaccharides) and, in the latter, the position of the O-glycosidic bond should be deduced from the MS, after acid hydrolysis. Three new C-glycosylflavones have been characterized in this way from Spergularia rubra and Stellaria holostea.  相似文献   

4.
Seven well-trained male cyclists were studied during 105 min of cycling (65% of maximal oxygen uptake) and a 15-min "performance ride" to compare the effects of 4- and 8-h preexercise carbohydrate (CHO) feedings on substrate use and performance. A high CHO meal was given 1) 4-h preexercise (M-4), 2) 8-h preexercise (M-8), 3) 4-h preexercise with CHO feedings during exercise (M-4CHO), and 4) 8-h preexercise with CHO feedings during exercise (M-8CHO). Blood samples were obtained at 0, 15, 60, 105, and 120 min and analyzed for lactate, glucose, insulin, and glycerol. Total work output during the performance ride was similar for the M-4 (217,893 +/- 13,348 N/m) and M-8 trials (216,542 +/- 13,905) and was somewhat higher for the M-4CHO (223,994 +/- 14,387) and M-8CHO (224,702 +/- 15,709) trials (P = 0.059, NS). Glucose was significantly elevated throughout exercise, and insulin levels were significantly elevated at 15 and 60 min during M-4CHO and M-8CHO compared with M-4 and M-8 trials. Glycerol levels were significantly lower during the CHO feeding trials compared with placebo and were not significantly different during exercise when the subject had fasted an additional 4 h. The results of this study suggest that when preexercise meals are ingested 4 or 8 h before submaximal cycling exercise, substrate use and performance are similar.  相似文献   

5.
The 4-6-8 method of sequence analysis   总被引:1,自引:0,他引:1  
A new method to obtain more sequence data from a single gel run is described. This method allows the reading of over 500 bases of sequence data from a single gel by taking advantage of the differential migration of specific sized dideoxy terminated chain lengths in sequencing gels containing variable percentages of acrylamide. The method is easy to use, requires no special equipment and requires no special technical abilities. We feel the methodology described will be useful for the average laboratory doing sequencing work.  相似文献   

6.
X-ray diffraction studies have been made on the effects of cations upon the dipalmitoyl phosphatidylcholine/water system, which originally consists of a lamellar phase with period of 64.5 A and of excess water. Addition of 1 mM CaCl2 destroys the lamellar structure and makes it swell into the excess water. The lamellar phase, however, reappears when the concentration of CaCl2 increases: a partially disordered lamellar phase with the repeat distance of 150-200 A comes out at the concentration of about 10 mM, the lamellar diffraction lines become sharp and the repeat distance decreases with increasing CaCl2 concentration. A small amount of uranyl acetate destroys the lameellar phase in pure water. MgCl2 induces the lamellar phase of large repeat distance, whereas LiCl, NaCl, KCl, SrCl2 and BaCl2 exhibit practically no effect by themselves. Addition of cholesterol to the phosphatidylcholine bilayers tends to stabilize the lamellar phase. The high-angle reflections indicate that molecular arrangements in phosphatidylcholine bilayers change at CaCl2 concentrations around 0.5 M. The bilayers at high CaCl2 concentration seem to consist of two phases of pure phosphatidylcholine and of equimolar mixture of phosphatidylcholine and cholesterol.  相似文献   

7.
Kuhn AN  Li Z  Brow DA 《Molecular cell》1999,3(1):65-75
The pre-mRNA 5' splice site is recognized by the ACAGA box of U6 spliceosomal RNA prior to catalysis of splicing. We previously identified a mutant U4 spliceosomal RNA, U4-cs1, that masks the ACAGA box in the U4/U6 complex, thus conferring a cold-sensitive splicing phenotype in vivo. Here, we show that U4-cs1 blocks in vitro splicing in a temperature-dependent, reversible manner. Analysis of splicing complexes that accumulate at low temperature shows that U4-cs1 prevents U4/U6 unwinding, an essential step in spliceosome activation. A novel mutation in the evolutionarily conserved U5 snRNP protein Prp8 suppresses the U4-cs1 growth defect. We propose that wild-type Prp8 triggers unwinding of U4 and U6 RNAs only after structurally correct recognition of the 5' splice site by the U6 ACAGA box and that the mutation (prp8-201) relaxes control of unwinding.  相似文献   

8.
Biliary tract infection with the Group I carcinogenic liver fluke Opisthorchis viverrini is associated with severe inflammation leading to cholangiocarcinoma--a major biliary cancer in Southeast Asia. However, mechanism(s) by which the liver fluke induces host mucosal immune/inflammatory responses is unclear. In the present study we address whether a normal immortalized human cholangiocyte cell line (H69 cells) recognizes and responds to O. viverrini excretory/secretory products (OVES). Expression of multiple TLRs, activation of NF-κB, and expression of pro-inflammatory cytokines were monitored in the presence and absence of OVES. Our results showed that OVES induced increased cholangiocyte TLR4 mRNA expression, induced IκB-α degradation in a MyD88-dependent manner, and activated NF-κB nuclear translocation. Moreover, OVES induced expression and secretion of the strong chemoattractant chemokine interleukin 8 (IL-8) and pro-inflammatory cytokine IL-6. These results demonstrate that secreted/excreted products of O. viverrini are recognized by human cholangiocytes and initiate innate mucosal immunity/inflammatory cascades, a primary event in the pathogenesis of opisthorchiasis and cholangiocarcinoma.  相似文献   

9.
10.
Twelve medical house officers were tested on a battery of memory, concentration, and work related tasks after three conditions: a night spent off duty; a night spent on call; and a night spent admitting emergency cases. Short term recall, but not digit span, concentration, or work related abilities, was impaired after a night of emergency admissions. A night spent on call had no effect on cognitive performance. Self reported mood scores showed that house officers were more deactivated (indicating a lack of vigour and drive) after nights of emergency admissions but not after nights on call. Significant between subject differences were found for five of the eight cognitive tests. Though loss of sleep and long hours of work have an effect on memory and mood, the individual differences among doctors are the main source of the variance in performance of tasks.  相似文献   

11.
小麦-簇毛麦6VS/6AL易位染色体对小麦农艺性状的影响   总被引:1,自引:0,他引:1  
南京农业大学细胞遗传研究所选育的小麦-簇毛麦6VS/6AL易位系在6VS上携有Pm21基因,用它作抗源已选育出一批高抗白粉病的新品系和新品种。为了研究6VS/6AL易位染色体对普通小麦农艺性状的影响,本研究选用由不同生态类型的推广品种与6VS/6AL易位系经过杂交回交选育的11个高代品系(种)及其轮回亲本和3份涉及6VS/6AL的高代分离品系以及5个F2群体,对产量、株高、穗长、穗粒数、穗粒重和千粒重等农艺性状进行比较分析。结果表明,6VS/6AL易位染色体对后代的小穗数、穗粒数、穗粒重和产量等农艺性状没有表现出明显的影响,对穗长和千粒重表现出一定的正向效应。多数6VS/6AL衍生品系的株高与亲本相比有所增加,但在同一组合的不同品系之间表现出一定的差异,在育种过程中通过选择能够改变增高趋势。6VS/6AL易位系对白粉病免疫,并且遗传稳定,对小麦的抗病育种是很有潜力的抗源亲本。  相似文献   

12.
13.
Signal transduction pathways in eukaryotic cells integrate diverse extracellular signals, and regulate complex biological responses such as growth, differentiation and death. One group of proline-directed Ser/Thr protein kinases, the mitogen-activated protein kinases (MAPKs), plays a central role in these signalling pathways. Much attention has focused in recent years on three subfamilies of MAPKs, the extracellular signal regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs) and the p38 MAPKs. However, the ERK family is broader than the ERK1 and ERK2 proteins that have been the subject of most studies in this area. Here we overview the work on ERKs 3 to 8, emphasising where possible their biological activities as well as distinctive biochemical properties. It is clear from these studies that these additional ERKs show similarities to ERK1 and ERK2, but with some interesting differences that challenge the paradigm of the archetypical ERK1/2 MAPK pathway.  相似文献   

14.
15.
Seafaring is a hazardous occupation with high death and injury rates, but the role of seafarer fatigue in these events is generally not well documented. The International Maritime Organization has identified seafarer fatigue as an important health and safety issue. Most research to date has focused on more regularly scheduled types of operations (e.g., merchant vessels, ferries), but there is relatively little information on commercial fishing, which often involves high day-to-day and seasonal variability in work patterns and workload. The present study was designed to monitor the sleep and sleepiness of commercial fishermen at home and during extended periods at sea during the peak of the hoki fishing season, with a view to developing better fatigue management strategies for this workforce. Sleep (wrist actigraphy and sleep diaries) and sleepiness (Karolinska Sleepiness Scale [KSS] before and after each sleep period) of 20 deckhands were monitored for 4-13 days at home and for 5-9 days at sea while working a nominal 12 h on/6 h off schedule. On the 12 h on/6 hoff schedule, there was still a clear preference for sleep at night. Comparing the last three days at home and the first three days at sea showed that fishermen were more likely to have split sleep at sea (Wilcoxon signed ranks p < 0.001), but the median sleep/24 h did not differ significantly by location (5.9 h at sea vs. 6.7 h at home). However, on 23% of days at sea, fishermen obtained < 4 h total sleep/24 h, compared to 3% of days at home ( p(chi 2) < 0.01). Sleep efficiency, mean activity counts/min sleep, and subjective ratings of sleep quality did not differ significantly between the last three days at home and the first three days at sea. However, sleepiness ratings remained higher after sleep at sea (Wilcoxon signed ranks p < 0.05), with fishermen having post-sleep KSS ratings >or= 7 on 24% of days at sea vs. 9% of days at home (Wilcoxon signed ranks p < 0.01). This work adds to the limited number of studies that objectively monitored the sleep of seafarers. It has the strength of operational fidelity but the weakness that large inter- and intra-individual variability in sleep, combined with the small sample size, limited the power of the study to detect statistically significant differences between sleep at home and at sea. The clear preference for sleep at night during the 12 h on/6 h off schedule at sea is consistent with the expectation that this 18 h duty/rest cycle is outside the range of entrainment of the circadian pacemaker. High levels of acute sleep loss, and residual sleepiness after sleep, were much more common at sea than at home. The longer duration of trips during the peak of the fishing season increases the risk of performance impairment due to greater cumulative sleep loss than would be expected on typical three-day trips. Key fatigue management strategies in this environment include that fishermen report to work as well rested as possible. Once at sea, the day-to-day variability in activities due to uncontrollable factors, such as fishing success, repairing gear, and weather conditions, mean that contingency planning is required for managing situations where the entire crew have experienced long periods of intensive work with minimum recovery opportunities.  相似文献   

16.
利用3类试验材料,即由不同生态类型的推广品种与小麦-簇毛麦6VS/6AL易位系经过杂交回交选育的高代品系(种),3份涉及6VS/6AL的高代分离品系以及5个以小麦-簇毛麦6VS/6AL易位系作杂交亲本的F2群体,对含有与不含有6VS/6AL易位染色体材料的产量、株高、穗长、德粒数、穗粒重和千粒重等农艺性状进行方差分析.结果表明,6VS/6AL易位染色体对后代的小穗数、穗粒数、穗粒重和产量等农艺性状没有表现出明显的影响,对穗长和千粒重表现出一定的正向效应.多数6VS/6AL衍生品系的株高与亲本相比有所增加,但在同一组合的不同品系之间表现出一定的差异,在育种过程中通过选择可改变增高趋势.6VS/6AL易位系对白粉病免疫,并且遗传稳定,对小麦的抗病育种是很有潜力的抗源亲本.  相似文献   

17.
Aging and demographic changes in Europe and other global economies have led to a discussion about postponing the legal retirement age; however, health and safety consequences for the workforce have not yet been examined. Thus, the aim of this study was to investigate the effects of lifetime exposure to shiftwork on health impairments and fitness for duty. Two samples of the police force from one of the states of the Federal Republic of Germany were used. One sample was collected in 2008-2009 with a self-administered Internet questionnaire (n = 705); the other sample was derived from employment records provided by the police force of the same federal state for the years 2002-2009 (n = 2460). Both samples contained information about the number of years worked in shiftwork across the entire working life and impairments to fitness for duty assessed by occupational physicians. Thus, the number of years of shiftwork until the diagnosis of the first reduction in fitness for duty could be calculated. Survival analyses were performed to estimate the risk (hazard rate) for experiencing a reduction in fitness for duty across lifetime exposure to shiftwork in years, controlling for age, sex, work type, and police district. Hazard estimates were compared across both samples to cross-validate the results. The findings indicated an increase in the risk of reduced fitness for duty with increasing number of years in shiftwork during the working life in both samples. The hazard rates followed an exponential trend, indicating a rapid increase in health impairments in particular beyond 20 yrs of shiftwork. These findings were consistent in both samples, collected with different methods and over different time periods, thus indicating high validity. Therefore, occupational stress factors, such as exposure to shiftwork, need to be taken into account when discussing the postponement of the legal retirement age.  相似文献   

18.
The effects of feeding ICRHa mice cyclic 12-, 8-, and 6-carbon compounds on glutathione S-transferase (GST) activity in the liver, intestinal mucosa, and the forestomach were determined. The compounds used for this study were 1,5,9-trans,trans,cis-cyclododecatriene, 1,2-trans-5,6-trans-9,10-cis-cyclododecatriene-1,2-oxide, cyclododecanol, cyclododecene oxide, cyclododecane, 1,5-cyclooctadiene, cyclooctene oxide, cyclohexene, and cyclohexene oxide. The unsaturated cyclic 12-carbon compounds elicited the greatest increase in GST activity. Thus, feeding 1,5,9-trans,trans,cis-cyclododecatriene increased this activity almost 4-fold in the livers and the intestinal mucosa of experimental animals. Cyclic 8-carbon compounds were less effective and feeding the cyclic 6-carbon compounds did not result in any significant increase in GST activity. None of the compounds elicited increased GST activity in the fore-stomach. Previous studies have shown that compounds inducing increased GST activity can protect against chemical carcinogens. It remains to be determined whether the compounds identified in the present investigation as inducers of this enzyme system will have such protective capacities.  相似文献   

19.
International Journal of Peptide Research and Therapeutics - Nt8U is a peptide analog of the N-terminal 13 residue fragment of the satiety peptide obestatin with Gly (8) being replaced by...  相似文献   

20.
Five 2-substituted 6/7-methoxy-l,4-benzodioxan-7/6-carbaldehydes and 6-methoxy-l,4-benzodioxan-7-carbaldehyde available for the syntheses of insecticidal neolignan analogs were prepared from 4/3-benzyloxy-3/4-hydroxybenzaldehydes and l,4-benzodioxan-6-carbaldehyde, respectively.  相似文献   

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