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1.
Stina M. Oredsson Martin Kanje Pierre S. Mamont Joseph Wagner Olle Heby 《Molecular and cellular biochemistry》1986,70(1):89-96
Summary Depletion of the putrescine and spermidine content of Ehrlich ascites tumor cells by -difluoromethylornithine (DFMO) treatment results in at least a 1500-fold increase in the decarboxylated S-adenosylmethionine (deSAM) content. The accumulation of this adenine nucleoside occurs because of the absence of putrescine and spermidine to act as aminopropyl group acceptors in the spermidine and spermine synthase reactions and because of an increase in S-adenosylmethionine decarboxylase activity. The fact that the synthesis of deSAM continues in DFMO-treated cells makes the pathway an adenine trap. This prompted a study of the adenine nucleotide pools. High-performance liquid chromatographic analysis showed that the total adenine nucleotide pool increased, rather than decreased, as a result of DFMO treatment; the major contributors to the increase being ATP and ADP, which increased 2.6 and 1.9 times, respectively. The cellular content of other ribonucleotides increased as well, particularly that of UTP and CTP. When putrescine was added together with DFMO, the increases in cellular ribonucleotide contents were prevented, showing that they were indeed caused by polyamine depletion. 相似文献
2.
Acyl lipids and pigments were analyzed in young plants of garden pea, spring wheat and spinach exposed to < 5 or 65 nl l?1 ozone 12 h per day for 6 days. In one set of experiments, the plants were exposed to 14CO2 for 2 h 3 days prior to ozone exposure. The plants responded differently to the moderately enhanced level of ozone used Spinach was not at all sensitive while in both pea and wheat, leaves of different ages differed in ozone sensitivity. In pea, ozone sensitivity increased with leaf age. In the second and third oldest leaves, the amounts of galactolipids per leaf area and the proportions of 18:3 of the total lipid extract and of phosphatidylglycerol decreased. In the second oldest leaf, ozone also caused a decreased proportion of 18:3 of monogalactosyldiacylglycerol. In the fourth oldest leaf, lipid composition and galactolipid unsaturation was unaffected, but ozone caused decreased leaf expansion resulting in increased acyl lipid content per leaf area. In both the first and second leaves of wheat, ozone fumigation caused a marked decrease in the content of monogalactosyldiacylglycerol and in the first leaf, the contents of phosphatidylcholine and phosphatidylethanolamine increased. The proportion of 18:3 in phosphatidylcholine was larger in ozone-fumigated than in control plants, while the reverse applied for phosphatidylglycerol. In the oldest sampled leaves of pea and wheat, ozone caused an increase in the radioactivity associated with β-carotene, indicating increased turnover. Thus, while spinach was unaffected, in both pea and wheat ozone caused a decrease in the proportion of chloroplast membrane lipids to non-chloroplast membrane lipids in older leaves while younger leaves were less sensitive. 相似文献
3.
Stina K. Lien Håvard Sletta Trond E. Ellingsen Svein Valla Elon Correa Royston Goodacre Kai Vernstad Sven Even Finborud Borgos Per Bruheim 《Metabolomics : Official journal of the Metabolomic Society》2013,9(2):403-417
Metabolic profiling of Pseudomonas fluorescens SBW25 and various mutants derived thereof was performed to explore how the bacterium adapt to changes in carbon source and upon induction of alginate synthesis. The experiments were performed at steady-state conditions in nitrogen-limited chemostats using either fructose or glycerol as carbon source. Carbon source consumption was up-regulated in the alginate producing mutant with inactivated anti-sigma factor MucA. The mucA- mutants (also non-alginate producing mucA- control strains) had a higher dry weight yield on carbon source implying a change in carbon and energy metabolism due to the inactivation of the anti-sigma factor MucA. Both LC–MS/MS and GC–MS methods were used for quantitative metabolic profiling, and major reorganization of primary metabolite pools in both an alginate producing and a carbon source dependent manner was observed. Generally, larger changes were observed among the phosphorylated glycolytic metabolites, the pentose phosphate pathway metabolites and the nucleotide pool than among amino acids and citric acid cycle compounds. The most significant observation at the metabolite level was the significantly reduced energy charge of the mucA- mutants (both alginate producing and non-producing control strains) compared to the wild type strain. This reduction was caused more by a strong increase in the AMP pool than changes in the ATP and ADP pools. The alginate-producing mucA- mutant had a slightly increased GTP pool, while the GDP and GMP pools were strongly increased compared to non-producing mucA- strains and to the wild type. Thus, whilst changes in the adenosine phosphate nucleotide pool are attributed to the mucA inactivation, adjustments in the guanosine phosphate nucleotide pool are consequences of the GTP-dependent alginate production induced by the mucA inactivation. This metabolic profiling study provides new insight into carbon and energy metabolism of the alginate producer P. fluorescens. 相似文献
4.
Stina Edelfeldt Anneli Lundkvist Johannes Forkman Theo Verwijst 《Bioenergy Research》2016,9(3):763-772
To evaluate the effects of weed competition and nitrogen fertilization on the early growth performance of willow, cuttings of the clone Tora (Salix schwerinii x S. viminalis) were planted in buckets together with model weeds (spring barley or white mustard) sown 15, 26, and 30 days after willow planting. The buckets were fertilized with 30 or 90 kg N ha?1. Willow with weeds sown after 15 days produced less biomass and smaller leaf area and had a lower maximum shoot height compared to willow planted without weeds and willow with weeds sown after 26 or 30 days. Fertilization with 90 kg N ha?1 gave higher willow biomass production in willow with weeds sown after 26 or 30 days. Type of model weed had no effect on willow performance. Weed biomass and maximum shoot height were higher in weeds planted without willows compared to the willow-weed mixtures. A high nitrogen level gave more weed biomass when planted without willows and in the willow-weed mixture with weeds sown after 15 days. We conclude that for the given high density of willow, competition from weeds emerging soon after willow planting had strong effect on early production. Furthermore, if there is a risk of weed infestation, fertilization should be delayed. 相似文献
5.
Mattila R Alanen K Syrjänen S 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2004,26(5):278-284
OBJECTIVE: To assess the presence of aneuploidy in oral lichen planus (OLP) and its usefulness as a prognostic marker. STUDY DESIGN: Eighty-one formalin-fixed, paraffin-embedded biopsy samples taken from atrophic-erosive OLP from 70 patients were studied. Approximately 150 random nuclei in basal and/or parabasal epithelia were analyzed with static cytometry. RESULTS: Aneuploidy was detected in 41% of samples. OLPs with ulcerations or location in the tongue had significantly higher values, respectively, for the 2.5c exceeding rate (ER) (p<0.001 and 0.001) and proliferation index (PI) (p = 0.012 and 0.013) than did lesions without ulcerations or at other locations. 2.5c ER was significantly higher in dysplastic OLP lesions (p < 0.001), and the significant value (p = 0.001)for 2.5c ER discriminating DNA aneuploidy was 15.3%. In multivariate analysis only the G2/M ER (G2/MER) was a significant independent predictor of developing cancer in OLP (OR 2.349, 95% CI 1.39-3.97, p = 0.001). CONCLUSION: Ulcerated atrophic-erosive OLPs of the tongue and with dysplasia are at increased risk of cancer development. 2.5c ER, PI and G2/MER might be useful in prognosticating the increased risk of malignancy in OLP. 相似文献
6.
Myosin heavy chain kinase A (MHCK A) modulates myosin II filament assembly in the amoeba Dictyostelium discoideum. MHCK A localization in vivo is dynamically regulated during chemotaxis, phagocytosis, and other polarized cell motility events, with preferential recruitment into anterior filamentous actin (F-actin)-rich structures. The current work reveals that an amino-terminal segment of MHCK A, previously identified as forming a coiled-coil, mediates anterior localization. MHCK A co-sediments with F-actin, and deletion of the amino-terminal domain eliminated actin binding. These results indicate that the anterior localization of MHCK A is mediated via direct binding to F-actin, and reveal the presence of an actin-binding function not previously detected by primary sequence evaluation of the coiled-coil domain. 相似文献
7.
Stina?EdelfeldtEmail author Anneli?Lundkvist Johannes?Forkman Theo?Verwijst 《Bioenergy Research》2015,8(2):796-806
To assess the effects of different planting systems on early performance (survival, shoot emergence time, number of shoots, maximum shoot height and biomass shoot production) of willow, cuttings of varying lengths were planted horizontally at different depths and compared with vertically planted cuttings. Cutting lengths of (i) 25–200 cm and (ii) 7–21 cm were studied in a field experiment and in a box experiment, respectively. Shorter cuttings planted deeper had a lower survival rate and emerged a few days later compared to longer cuttings planted shallower. The performance was considerably higher at the apical part of the cuttings, regardless of cutting length. Longer cuttings planted shallow had a higher performance. Vertically planted cuttings produced more biomass and shoots per length unit than horizontally planted cuttings. We conclude that planting systems based on the use of longer horizontally planted cuttings would probably lead to an uneven establishment and gaps in the stand caused by apical dominance. Also, to achieve the same performance, the need of planting material would be considerably higher compared to systems with vertically planted cuttings. To obtain a fast and more even early establishment of willows, we recommend the use of vertically planted cuttings with a length of at least 20 cm. If cuttings are planted horizontally, they should not be planted deeper than 5 cm. 相似文献
8.
Ann-Charlotte Karlsson Stefan Alenius Camilla Björkman Ylva Persson Stina Englund 《Acta veterinaria Scandinavica》2010,52(1):1-4
Background
Reproductive disorders associated with chlamydial infection have been reported worldwide in cattle and there are indications of potential venereal transmission.Methods
Semen samples from 21 dairy bulls and cauda epididymidis tissue samples from 43 beef bulls were analysed for chlamydial agent by real-time polymerase chain reaction (PCR) including an internal amplification control (mimic). Additionally, presence of antibodies against Chlamydophila (Cp.) abortus among the bulls was investigated with the commercial Pourquier® ELISA Cp. abortus serum verification kit.Results
No chlamydial agent was detected by PCR in either the semen samples or in the tissue samples. Additionally, no antibodies against Cp. abortus were detected.Conclusions
The results suggest that Cp. abortus is very rare, or absent in Swedish bulls and thus the risk for venereal transmission of chlamydial infection through their semen is low. However, because Chlamydophila spp. infection rates seem to differ throughout the world, it is essential to clarify the relative importance of transmission of the infection through semen on cattle fertility. 相似文献9.
David G. Angeler Cristina Trigal Stina Drakare Richard K. Johnson Willem Goedkoop 《Oecologia》2010,164(1):231-241
The complex nature of ecological systems limits the unambiguous determination of mechanisms that drive resilience to natural
disturbance or anthropogenic stress. Using eight-year time series data from boreal lakes with and without bloom formation
of an invasive alga (Gonyostomum semen, Raphidophyceae), we studied resilience of phytoplankton communities in relation to recurring bloom impacts. We first characterized
phytoplankton community dynamics in both lake types using univariate metrics of community structure (evenness, species richness,
biovolume and Simpson diversity). All metrics, except species richness, were substantially altered and showed an inherent
stronger variability in bloom lakes relative to reference lakes. We assessed resilience mechanisms using a multivariate time
series modelling technique. The models captured clear successional dynamics of the phytoplankton communities in all lakes,
whereby different groups of species were substituted sequentially over the ice-free period. The models also identified that
G. semen impacts in bloom lakes were only manifested within a single species group, not across species groups, highlighting the rapid
renewal of the phytoplankton communities upon bloom collapse. These results provide empirical support of the cross-scale resilience
model. Cross-scale resilience could provide an explanation for the paradox that similar species richnesses are seen in bloom-forming
lakes and reference lakes despite the clear difference between the community features of the two different sets of lakes investigated. 相似文献
10.
Plasma membranes were isolated from leaves of 16-day-old garden pea, Pisum sativum L., that had been grown in the absence or presence of 65 nl l−1 ozone for 4 days prior to membrane isolation. Plasma membranes from ozone-fumigated plants contained significantly more acyl lipids per protein than those from leaves of plants grown in filtered air on a molar/weight ratio. The ratio between the major acyl lipids, phosphatidylethanolamine (PE) and phosphatidylcholine (PC), also increased due to the ozone fumigation, while the fatty acid unsaturation level was unaltered in total plasma membrane acyl lipids, as well as in PC and PE. The amount of free sterols per protein was unaltered, but the percentage of campesterol increased, concomitant with a decrease in stigmasterol. The dynamical properties of the isolated plasma membranes were assessed using Laurdan fluorescence spectroscopy, which monitors water penetration and mobility at the hydrophilic-hydrophobic interface of the membrane. At 0°C, the molecular mobility was slightly lower in plasma membranes from ozone-fumigated plants than in plasma membranes from control plants, possibly reflecting the increased PE/PC, campesterol/stigmasterol and lipid/protein ratios, and suggesting that ozone-fumigated pea plants may be more susceptible to freezing injuries. 相似文献