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101.
Gerda Tyrsted Pao-chang Chao Birgitte Munch-Petersen 《Molecular and cellular biochemistry》1987,76(1):27-34
Deoxycytidylate deaminase isolated from normal human lymphocytes and from mononuclear leucocytes from patients with acute lymphoblastic leukemia, chronic lymphocytic leukemia and acute monocytic leukemia has been characterized in regard to the substrate, dAMP and the allosteric regulators dCTP and dTTP. The enzymes exhibited sigmoidal initial velocity versus dCMP concentration whereas in the presence of the activator, dCTP, Michaelis-Menten kinetics were obtained.At saturating substrate concentrations dTTP acted as an allosteric inhibitor of the enzyme isolated from non-stimulated as well as from stimulated lymphocytes. However, the enzymes isolated from the leukemic cells had lost the allosteric regulation by dTTP.At low substrate concentrations the competitive inhibitor, dAMP, activated all the enzymes. This activation was abolished in the presence of dCTP which indicates that dAMP might be involved in the regulation of dCMP deaminase activity and thus influence the dCTP and dTTP pools under physiological conditions.Abbreviations dCMP deaminase
deoxycytidylate deaminase
- PHA
Phytohemagglutinin
- ALL
acute lymphoblastic leukemia
- CLL
chronic lymphocytic leukemia
- AMOL
acute monocytic leukemia
- WBC
white blood cells 相似文献
102.
103.
The state of the art for thermophilic UASB reactors is discussed focusing on the start-up of UASB reactors, the influence of the waste water composition and temperature on the development and maintenance of thermophilic granules, and the microbial composition and structure of thermophilic granules. 相似文献
104.
Ingrid Holst Olsen Nanna Holt Seppo W. Langer Jane P. Hasselby Henning Gr?nb?k Jens Hillings? Masti Mahmoud Morten Ladekarl Lene H. Iversen Andreas Kj?r Birgitte H. Federspiel Ulrich Knigge 《PloS one》2015,10(2)
BackgroundAppendiceal goblet cell carcinoids (GCCs) exhibit neuroendocrine and adenocarcinoma features.ResultsMedian age for f/m was 59/58 years, respectively, and similar for localized and disseminated disease. At diagnosis 54 patients had localized appendiceal disease (f/m: 29/25). According to TNM 24% had Stage I, 70% had Stage II and 6% had Stage III. Twenty-nine patients had disseminated disease (f/m: 27/2). Chromogranin A, synaptophysin and p53 were positive in >90%. Serotonin was positive in 70%. Median Ki67 index was 32% (6-75%) and higher in Tang group C (50%) compared to group A (30%; p<0.0001), and group B (30%; p<0.004). All patients had surgery. Sixty-three (76%) had radical resections including all patients with localized disease. Median OS was 83 months. The 1-, 5- and 10-year survival rates were 90%, 58%, and 38%, respectively. For localized disease OS was 164 months and 1-, 5- and 10-year survival rates were 100%, 80%, and 55%, respectively. For disseminated disease OS was 19 months and 1-, 5- and 10-year survival rates were 73%, 18% and 6%, respectively. The 1-, 5- and 10 year-survival rates for f/m were 87%/96%, 49%/76% and 31%/57%, respectively (p = 0.02). According to the Tang classification group A, B, and C OS was 118, 83 and 20 months, respectively (p = 0.0002).ConclusionThe Tang classification was found to be a significant prognostic factor, while the Ki67 index was not. Localized GCCs occurred equally in males and females, while disseminated GCCs were mostly seen in females. Median age of patients with localized disease and disseminated disease was identical. Cox regression analysis found Stage IV, focally positive synaptophysin and non-radical surgery as strongest negative prognostic factors. 相似文献
105.
Structural analysis of the reducing side of photosystem I (PSI) has been carried out using chemical cross-linking and monospecific antibodies. Incubation of PSI isolated from barley (Hordeum vulgare L.) with the hydrophilic cross-linking agent N-ethyl-3-[3-(dimethylamino) propyl]-carbodiimide leads to cross-linking of the PSI-D subunit with the PSI-E and PSI-H subunits. In the presence of ferredoxin, cross-linking results in the formation of cross-linked products composed of PSI-D, PSI-E and ferredoxin and in a block in steady state NADP+ photoreduction. No cross-linking of ferredoxin occurs at elevated ionic strength or using heat-denatured ferredoxin. Cross-linking of ferredoxin does not inhibit electron transfer from plastocyanin to methyl viologen. Steady state NADP+ photoreduction was analyzed in PSI or thyla-koids incubated with antibodies against individual PSI subunits. Incubation with antibodies against PSI-C, -H, -I, or -L had no effect on PSI activity, whereas antibodies against PSI-D or PSI-E had similar effects and caused a large decrease in activity. The results provide evidence that the PSI-D and PSI-E subunits are localized on the reducing side of PSI, forming a barrier between PSI-C and the stroma as well as a docking site for ferredoxin. The PSI-H subunit has an exposed, stromal domain but this does not appear to contribute to the ferredoxin docking. 相似文献
106.
107.
Richard P. Shefferson Tiiu Kull Michael J. Hutchings Marc‐André Selosse Hans Jacquemyn Kimberly M. Kellett Eric S. Menges Richard B. Primack Juha Tuomi Kirsi Alahuhta Sonja Hurskainen Helen M. Alexander Derek S. Anderson Rein Brys Emilia Brzosko Slavomir Dostálik Katharine Gregg Zdeněk Ipser Anne Jäkäläniemi Jana Jersáková W. Dean Kettle Melissa K. McCormick Ana Mendoza Michael T. Miller Asbjørn Moen Dag‐Inge Øien Ülle Püttsepp Mélanie Roy Nancy Sather Nina Sletvold Zuzana Štípková Kadri Tali Robert J. Warren II Dennis F. Whigham 《Ecology letters》2018,21(5):724-733
Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life‐history costs of sprouting, and of dormancy. Short‐lived and mycoheterotrophic species have higher proportions of dormant plants than long‐lived species and species with other nutritional modes. Foliage loss is associated with higher future dormancy levels, suggesting that carbon limitation promotes dormancy. Maximum dormancy duration is shorter under higher precipitation and at higher latitudes, the latter suggesting an important role for competition or herbivory. Study length affects estimates of some demographic parameters. Our results identify life historical and environmental drivers of dormancy. We also highlight the evolutionary importance of the little understood costs of sprouting and growth, latitudinal stress gradients and mixed nutritional modes. 相似文献
108.
Mark A. Ditmer John R. Fieberg Ron A. Moen Steve K. Windels Seth P. Stapleton Tara R. Harris 《Ecology and evolution》2018,8(17):9017-9033
Predators directly impact prey populations through lethal encounters, but understanding nonlethal, indirect effects is also critical because foraging animals often face trade‐offs between predator avoidance and energy intake. Quantifying these indirect effects can be difficult even when it is possible to monitor individuals that regularly interact. Our goal was to understand how movement and resource selection of a predator (wolves; Canis lupus) influence the movement behavior of a prey species (moose; Alces alces). We tested whether moose avoided areas with high predicted wolf resource use in two study areas with differing prey compositions, whether avoidance patterns varied seasonally, and whether daily activity budgets of moose and wolves aligned temporally. We deployed GPS collars on both species at two sites in northern Minnesota. We created seasonal resource selection functions (RSF) for wolves and modeled the relationship between moose first‐passage time (FPT), a method that discerns alterations in movement rates, and wolf RSF values. Larger FPT values suggest rest/foraging, whereas shorter FPT values indicate travel/fleeing. We found that the movements of moose and wolves peaked at similar times of day in both study areas. Moose FPTs were 45% lower in areas most selected for by wolves relative to those avoided. The relationship between wolf RSF and moose FPT was nonlinear and varied seasonally. Differences in FPT between low and high RSF values were greatest in winter (?82.1%) and spring (?57.6%) in northeastern Minnesota and similar for all seasons in the Voyageurs National Park ecosystem. In northeastern Minnesota, where moose comprise a larger percentage of wolf diet, the relationship between moose FPT and wolf RSF was more pronounced (ave. across seasons: ?60.1%) than the Voyageurs National Park ecosystem (?30.4%). These findings highlight the role wolves can play in determining moose behavior, whereby moose spend less time in areas with higher predicted likelihood of wolf resource selection. 相似文献
109.
Jens C. Frisvad Robert a. Samson Birgitte R. Rassing Marjolein I. van der Horst F.T.J. van Rijn J. Stark 《Antonie van Leeuwenhoek》1997,72(2):119-126
The new species Penicillium discolor, frequently isolated from nuts, vegetables and cheese is described. It is characterised by rough, dark green conidia, synnemateous growth on malt agar and the production of the secondary metabolites chaetoglobosins A, B and C, palitantin, cyclopenin, cyclopenol, cyclopeptin, dehydrocyclopeptin, viridicatin and viridicatol. It also produces the mouldy smelling compounds geosmin and 2-methyl-isoborneol, and a series of specific orange to red pigments on yeast extract sucrose agar, hence the epithet discolor. P. discolor resembles P. echinulatum morphologically but on basis of the secondary metabolites is also related to P. expansum, P. solitum and P. crustosum. 相似文献
110.