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61.
Grete Grindal Arild Ernstsen James B. Reid Olavi Junttila Bente Lindgård Roar Moe 《Physiologia plantarum》1998,102(4):523-531
Gibberellin (GA) is believed to be involved in thermoperiodic stem elongation. With this in mind, we studied the correlation between gibberellin A1 (GA1) levels and stem elongation affected by alternating day (DT) and night temperature (NT) in 5 genotypes of Pisum sativum differing in their degree of dwarfism. The endogenous GA content in the tissue of two of the genotypes was determined by combined gas chromatography and mass spectrometry. The wild genotype developed 40 to 50% shorter stems and internodes under a low DT and high NT combination (negative difference [DIF] between DT and NT, DT/NT 15.5/21.5 or 14/24°C) than under the opposite regime of high DT and low NT (positive DIF, DT/NT 22.5/16.5 or 24/14°C). The GA biosynthetic mutants ls and le, and the auxin and brassinosteroid mutant lkb responded in a similar way, but not as strongly as the wild type. The stem length of the GA-insensitive slender mutant (la crys) was reduced by only 8% under negative compared to positive DIF. In the wild type endogenous GA levels decreased by 60% from positive to negative DIF in the upper part of the stem. Further, there was a corresponding decrease in the levels of precursors to GA1, i.e. GA53, GA44, GA19 and GA20, while 2β-hydroxylated GA20 and GA1, GA29 and GA8, respectively, were unaffected by DIF. A similar increase in the ratios of GA29 to GA20 and GA8 to GA1 from positive to negative DIF was seen in the stem tissue of the le mutant as in the wild type. The temperature regimes affected the levels of GA1 and its precursors in combined leaf and petiole samples and in the shoot tip in a similar manner as in the stem tissue. However, the different temperature regimes did not affect the ratio of GA8/GA1 in the shoot tip. The results indicate that altered stem elongation of the pea plants in response to diurnal temperature alternations may be mediated by changes in endogenous levels of GA1. The GA1 levels may be controlled by an effect of DIF on both biosynthetic and inactivation steps. 相似文献
62.
Characterization of glutathione S-transferase of Taenia solium. 总被引:5,自引:0,他引:5
A Taenia solium glutathione-S-transferase fraction (SGSTF) was isolated from a metacestode crude extract by affinity chromatography on reduced glutathione (GSH)-sepharose. The purified fraction displayed a specific glutathione S-transferase (GST) activity of 2.8 micromol/min/mg and glutathione peroxidase selenium-independent activity of 0.22 micromol/min/mg. Enzymatic characterization of the fraction suggested that the activity was closer to the mammalian mu-class GSTs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration, and enzyme activity analysis showed that the fraction was composed of a major band of Mr = 26 kd and that the active enzyme was dimeric. Immunohistochemical studies using specific antibodies against the major 26-kd band of the SGSTF indicated that GST protein was present in the tegument, parenchyma, protonephridial, and tegumentary cytons of the T. solium metacestode. Antibodies generated against the SGSTF tested in western blot showed cross-reactivity against GSTs purified from Taenia saginata, T. taeniaeformis, and T. crassiceps, but did not react with GSTs from Schistosoma mansoni, or mice, rabbit, and pig liver tissue. Furthermore, immunization of mice with SGSTF reduced the metacestode burden up to 74.2%. Our findings argue in favor of GST having an important role in the survival of T. solium in its hosts. 相似文献
63.
64.
Eva Hedmark Øystein Flagstad Peter Segerström Jens Persson Arild Landa Hans Ellegren 《Conservation Genetics》2004,5(3):405-410
Non-invasive genetic analyses are important for studies of species that are rare, sensitive or at risk of extinction. This study investigates the possibility of using faeces and urine to obtain microsatellite genotypes for individual identification of wolverines (Gulo gulo). The reliability of the employed method was assessed by analysing independent amplifications of non-invasive samples (a multiple-tube approach) and by comparing genotypes obtained from faeces to genotypes obtained from blood or tissue of the same individual. Ten microsatellite markers were successfully amplified in 65% of the faecal samples (n = 32) and 40% of the urine samples (n = 22). Allelic dropout was found in 12 and 14% of the amplifications from extracts of faeces and urine, respectively. Nevertheless, all multi-locus genotypes were correct, as judged from comparison to data from tissue or blood samples, after three replicates. These results suggest that a non-invasive approach based on DNA-analysis of faeces can be a powerful tool in population monitoring of wolverines, potentially providing reliable estimates of population size and immigration rate. A second objective of the study was to develop markers for DNA-based sex identification in wolverines using non-invasive samples. We developed two Y-linked markers, one that was specific to wolverine and one that also successfully identified sex in another mustelid. Importantly, none of the markers amplified potential prey species such as reindeer or rodents. 相似文献
65.
66.
As determined by the yield of polyploid hepatocytes after X-irradiation of rats with a dose of 6 Gy the S-stage of the cell cycle was most radiosensitive; as to the yield of cells with chromosome aberrations the middle of the G1-stage was the most radiosensitive period of the cell cycle. The differences in the radiosensitivity of the cell cycle stages indicated that although primary lesions were similar molecular mechanisms leading to tre final effect were essentially different. 相似文献
67.
Siril S. Bakke Yuan Z. Feng Natasa Nikoli? Eili T. Kase Cedric Moro Camilla Stensrud Lisbeth Damlien Marianne O. Ludahl Rune Sandbu Brita Marie Solheim Arild C. Rustan J?ran Hjelmes?th G. Hege Thoresen Vigdis Aas 《PloS one》2015,10(3)
About 80% of patients with type 2 diabetes are classified as overweight. However, only about 1/3 of severely obese subjects have type 2 diabetes. This indicates that several severely obese individuals may possess certain characteristics that protect them against type 2 diabetes. We therefore hypothesized that this apparent paradox could be related to fundamental differences in skeletal muscle lipid handling. Energy metabolism and metabolic flexibility were examined in human myotubes derived from severely obese subjects without (BMI 44±7 kg/m2) and with type 2 diabetes (BMI 43±6 kg/m2). Lower insulin sensitivity was observed in myotubes from severely obese subjects with type 2 diabetes. Lipolysis rate was higher, and oleic acid accumulation, triacylglycerol content, and fatty acid adaptability were lower in myotubes from severely obese subjects with type 2 diabetes compared to severely obese non-diabetic subjects. There were no differences in lipid distribution and mRNA and protein expression of the lipases HSL and ATGL, the lipase cofactor CGI-58, or the lipid droplet proteins PLIN2 and PLIN3. Glucose and oleic acid oxidation were also similar in cells from the two groups. In conclusion, myotubes established from severely obese donors with established type 2 diabetes had lower ability for lipid accumulation and higher lipolysis rate than myotubes from severely obese donors without diabetes. This indicates that a difference in intramyocellular lipid turnover might be fundamental in evolving type 2 diabetes. 相似文献
68.
Ana Leonor Rivera Bruno Esta?ol Horacio Sentíes-Madrid Ruben Fossion Juan C. Toledo-Roy Joel Mendoza-Temis Irving O. Morales Emmanuel Landa Adriana Robles-Cabrera Rene Moreno Alejandro Frank 《PloS one》2016,11(2)
Diabetes Mellitus (DM) affects the cardiovascular response of patients. To study this effect, interbeat intervals (IBI) and beat-to-beat systolic blood pressure (SBP) variability of patients during supine, standing and controlled breathing tests were analyzed in the time domain. Simultaneous noninvasive measurements of IBI and SBP for 30 recently diagnosed and 15 long-standing DM patients were compared with the results for 30 rigorously screened healthy subjects (control). A statistically significant distinction between control and diabetic subjects was provided by the standard deviation and the higher moments of the distributions (skewness, and kurtosis) with respect to the median. To compare IBI and SBP for different populations, we define a parameter, α, that combines the variability of the heart rate and the blood pressure, as the ratio of the radius of the moments for IBI and the same radius for SBP. As diabetes evolves, α decreases, standard deviation of the IBI detrended signal diminishes (heart rate signal becomes more “rigid”), skewness with respect to the median approaches zero (signal fluctuations gain symmetry), and kurtosis increases (fluctuations concentrate around the median). Diabetes produces not only a rigid heart rate, but also increases symmetry and has leptokurtic distributions. SBP time series exhibit the most variable behavior for recently diagnosed DM with platykurtic distributions. Under controlled breathing, SBP has symmetric distributions for DM patients, while control subjects have non-zero skewness. This may be due to a progressive decrease of parasympathetic and sympathetic activity to the heart and blood vessels as diabetes evolves. 相似文献
69.
70.
Parthenogenetically activated, in vitro-matured bovine oocytes and parthenogenotes obtained at 2 to 4 days post activation were analyzed by 3H-thymidine autoradiography for the timing of the S-phase and for distribution of newly replicated DNA, respectively. Spread pronuclear parthenogenotes revealed that the DNA synthesis in electrically stimulated oocytes commenced at 14 h post activation. At 20 to 24 h, a maximum number of labeled pronuclei was reached (25 to 38%), and DNA synthesis persisted in some parthenogenotes up to 30 h post activation. The DNA labeling detected on semi-thin sections showed that the distribution of newly synthesized DNA in the nuclei of 3- to 16-cell parthenogenotes was mostly irregular or abnormal, documenting that the apparent morphological normalcy of parthenogenotes was in contrast to the data concerning the DNA synthesis and distribution. 相似文献