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71.
Hongkyu Yoon Sabine Leibeling Changyong Zhang Roland H. Müller Charles J. Werth Julie L. Zilles 《Biodegradation》2014,25(4):595-604
Delftia acidovorans MC1071 can productively degrade R-2-(2,4-dichlorophenoxy)propionate (R-2,4-DP) but not 2,4-dichlorophenoxyacetate (2,4-D) herbicides. This work demonstrates adaptation of MC1071 to degrade 2,4-D in a model two-dimensional porous medium (referred to here as a micromodel). Adaptation for 2,4-D degradation in the 2 cm-long micromodel occurred within 35 days of exposure to 2,4-D, as documented by substrate removal. The amount of 2,4-D degradation in the adapted cultures in two replicate micromodels (~10 and 20 % over 142 days) was higher than a theoretical maximum (4 %) predicted using published numerical simulation methods, assuming instantaneous biodegradation and a transverse dispersion coefficient obtained for the same pore structure without biomass present. This suggests that the presence of biomass enhances substrate mixing. Additional evidence for adaptation was provided by operation without R-2,4-DP, where degradation of 2,4-D slowly decreased over 20 days, but was restored almost immediately when R-2,4-DP was again provided. Compared to suspended growth systems, the micromodel system retained the ability to degrade 2,4-D longer in the absence of R-2,4-DP, suggesting slower responses and greater resilience to fluctuations in substrates might be expected in the soil environment than in a chemostat. 相似文献
72.
Olga Nadyeina Lyudmyla Dymytrova Anna Naumovych Sergyi Postoyalkin Silke Werth Saran Cheenacharoen Christoph Scheidegger 《Molecular ecology》2014,23(21):5164-5178
Population genetics of the tree‐colonizing lichen Lobaria pulmonaria were studied in the largest primeval beech forest of Europe, covering 10 000 ha. During an intensive survey of the area, we collected 1522 thallus fragments originating from 483 trees, which were genotyped with eight mycobiont‐ and 14 photobiont‐specific microsatellite markers. The mycobiont and photobiont of L. pulmonaria were found to consist of two distinct gene pools, which are co‐existing within small areas of 3–180 ha in a homogeneous beech forest. The small‐scale distribution pattern of the symbiotic gene pools show habitat partitioning of lineages associated with either floodplains or mountain forests. Using approximate Bayesian computation (ABC), we dated the divergence of the two fungal gene pools of L. pulmonaria as the Early Pleistocene. Both fungal gene pools survived the Pleistocene glacial cycles in the Carpathians, although possibly in climatically different refugia. Fungal diversification prior to these cycles and the selection of photobionts with different altitudinal distributions explain the current sympatric, but ecologically differentiated habitat partitioning of L. pulmonaria. In addition, the habitat preferences of the mycobiont are determined by other factors and are rather independent of those of the photobiont at the landscape level. The distinct gene pools should be considered evolutionarily significant units and deserve specific conservation priorities in the future, for example gene pool A, which is a Pliocene relict. 相似文献
73.
Lichens associated with old forest are commonly assumed to be negatively affected by tree logging or natural disturbances. However, in this study performed in a spruce-dominated sylvopastoral landscape in the Swiss Jura Mountains, we found that genetic diversity of the epiphytic old-forest lichen Lobaria pulmonaria depends on the type of disturbance. We collected 923 thalli from 41 sampling plots of 1 ha corresponding to the categories stand-replacing disturbance (burnt), intensive logging (logged) and uneven-aged forestry (uneven-aged), and analysed the thalli at six mycobiont-specific microsatellite loci. We found evidence for multiple independent immigrations into demes located in burnt and logged areas. Using spatial autocorrelation methods, the spatial scale of the genetic structure caused by the clonal and recombinant component of genetic variation was determined. Spatial autocorrelation of genotype diversity was strong at short distances up to 50 m in logged demes, up to 100 m in uneven-aged demes, with the strongest autocorrelation up to 150 m for burnt demes. The spatial autocorrelation was predominantly attributed to clonal dispersal of vegetative propagules. After accounting for the clonal component, we did not find significant spatial autocorrelation in gene diversity. This pattern may indicate low dispersal ranges of clonal propagules, but random dispersal of sexual ascospores. Genetic diversity was highest in logged demes, and lowest in burnt demes. Our results suggest that genetic diversity of epiphytic lichen demes may not necessarily be impacted by stand-level disturbances for extended time periods. 相似文献
74.
Introduction
Several studies have reported that TNFα is substantially increased within skin lesions of patients with discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE) and dermatomyositis (DM) compared to controls. Elevated TNFα has been reported in the sera of some patients with systemic lupus erythematosus, DLE and SCLE, but not in the sera of patients with DM. Because of the key pathogenic role of autoimmunity in these diseases, in this study we sought to evaluate TNFα production by a readily available source of immune cells (namely, peripheral blood mononuclear cells (PBMCs)) taken from controls and from patients with cutaneous lupus or DM. 相似文献75.
Patricia Kruchten Ruth Werth Emmanuel Bey Alexander Oster Sandrine Marchais-Oberwinkler Martin Frotscher Rolf W. Hartmann 《The Journal of steroid biochemistry and molecular biology》2009,114(3-5):200-206
The most potent estrogen estradiol (E2) plays a pivotal role in the initiation and progression of estrogen dependent diseases. 17β-Hydroxysteroid dehydrogenase type 1 (17βHSD1) catalyses the NADPH-dependent E2-formation from estrone (E1). It is often overexpressed in breast cancer and endometriosis. For this reason, inhibition of 17βHSD1 is a promising strategy for the treatment of these diseases. In the present paper, we investigate the estrogen responsive cell growth of T47-D breast cancer cells, the intracellular inhibitory activity of non-steroidal 17βHSD1-inhibitors and their effects on estrogen dependent cell growth in vitro. At equal concentrations the estrogens E1 and E2 induced the same extent of growth stimulation indicating fast intracellular conversion of E1 into E2. Application of inhibitors selectively prevented stimulation of proliferation evoked by E1-treatment whereas E2-mediated stimulation was not affected. Furthermore, intracellular E2-formation from E1 was significantly inhibited with IC50-values in the nanomolar range. In conclusion, our findings strongly support suitability of non-steroidal 17βHSD1-inhibitors for the treatment of estrogen dependent diseases. 相似文献
76.
Werth AJ 《Journal of morphology》2006,267(12):1415-1428
The role of cranial morphology in the generation of intraoral and oropharyngeal suction pressures in odontocetes was investigated by manipulating the jaw and hyolingual apparatus of submerged heads of three species presenting varied shapes. Hyoid and gular muscles were manually employed to depress and retract the tongue. Pressures were recorded at three locations in the oral cavity, as gape and site, speed, and force of pull were varied. A biomechanical model was also developed to evaluate pressure data. The species with the shortest, bluntest head and smallest mouth opening generated greater negative pressures. Suction generation diminished sharply as gape increased. Greatest negative pressures attained were around -45 mmHg (-6,000 Pa), a magnitude deemed suitable for capture of small live prey. Odontocetes utilizing this bidirectional flow system should profit by evolution of a rounder mouth opening through progressive shortening and widening of the rostrum and jaws, a trend evident in cranial measurements from fossil and recent odontocetes. Blunt heads correlate with anatomical, ecological, and behavioral traits associated with suction feeding. Small-gape suction (with minimally opened jaws) could be used by odontocetes of all head and oral shapes to draw prey sufficiently close to the mouth for suction ingestion or grasping via dentition. Principal limitations of the experimental and mathematical simulations include assumption of a stationary odontocete with static (open or closed) jaws and potential scaling issues with differently sized heads and gapes. 相似文献
77.
Alexander Oster Tobias Klein Ruth Werth Patricia Kruchten Emmanuel Bey Matthias Negri Sandrine Marchais-Oberwinkler Martin Frotscher Rolf W. Hartmann 《Bioorganic & medicinal chemistry》2010,18(10):3494-3505
17β-Hydroxysteroid dehydrogenase type 1 (17β-HSD1) catalyzes the reduction of estrone into estradiol, which is the most potent estrogen in humans. Lowering intracellular estradiol concentration by inhibition of this enzyme is a promising new option for the treatment of estrogen-dependent diseases like breast cancer and endometriosis. Combination of ligand- and structure-based design resulted in heterocyclic substituted biphenylols and their aza-analogs as new 17β-HSD1 inhibitors. The design was based on mimicking estrone, especially focusing on the imitation of the D-ring keto group with (substituted) heterocycles. Molecular docking provided insights into plausible protein–ligand interactions for this class of compounds. The most promising compound 12 showed an inhibitory activity in the high nanomolar range and very low affinity for the estrogen receptors α and β. Thus, compound 12 is a novel tool for the elucidation of the pharmacological relevance of 17β-HSD1 and might be a lead for the treatment of estrogen-dependent diseases. 相似文献
78.
? Premise of the study: Discovering missing ancestors is essential to understanding the evolutionary history of biodiversity on Earth. Evidence from extinct species can provide links for reconstructing intricate patterns of reticulate relationships among extant descendents. When fossils are unavailable and other evidence yields competing hypotheses to explain species ancestry, data from proteins and DNA can help resolve conflicts and generate novel perspectives. The identity of a parent shared by two tetraploid species in the cosmopolitan fern genus Dryopteris has remained elusive for more than 50 years. Based on available data, four hypotheses were developed previously, each providing a different resolution to this uncertainty. ? Methods: New molecular evidence from studies of isozymes and restriction site analysis of chloroplast DNA tested the competing hypotheses about the diploid ancestors of these two extant Dryopteris polyploids. ? Key results: The results falsify two of the hypotheses, resolve the uncertainty in the third, and support the fourth. ? Conclusions: Our data validate the prior existence of Dryopteris "semicristata," which was proposed 38 years ago as a diploid progenitor of the allotetraploids D. cristata and D. carthusiana but has never been collected. After developing a phylogeny using the new molecular data, we describe a plausible morphology for D. "semicristata" by extrapolating likely character states from related extant species. 相似文献
79.
Interactions of acid sphingomyelinase and lipid bilayers in the presence of the tricyclic antidepressant desipramine 总被引:1,自引:0,他引:1
The tricyclic antidepressant desipramine causes a decrease in cellular acid sphingomyelinase (A-SMase, EC 3.1.4.12) activity when added to culture medium of human fibroblasts. This effect can be prevented by incubation of the cells with the protease inhibitor leupeptin, which suggests that desipramine induces proteolytic degradation of the lysosomal enzyme. By using surface plasmon resonance (SPR, Biacore) we were able to monitor the interactions of A-SMase and substrate-containing lipid bilayers immobilized on the surface of a Pioneer trade mark L1 sensor chip. SPR binding curves show that the enzyme hardly dissociates from the lipid surface at acidic pH values. On the other hand, a drop in binding signals (resonance units, RU) of approximately 50% occurred after injection of 20 mM desipramine. Our findings indicate that desipramine interferes with the binding of A-SMase to the lipid bilayers and thereby displaces the enzyme from its membrane-bound substrate. The application of control substances suggests a key role for the cationic moiety of desipramine. We hypothesize that the displacement of the glycoprotein A-SMase from the inner membranes of late endosomes and lysosomes by desipramine renders it susceptible to proteolytic cleavage by lysosomal proteases. 相似文献
80.
Werth E Cote KA Gallmann E Borbély AA Achermann P 《American journal of physiology. Regulatory, integrative and comparative physiology》2002,283(2):R521-R526
Although repeated selective rapid eye movement (REM) sleep deprivation by awakenings during nighttime has shown that the number of sleep interruptions required to prevent REM sleep increases within and across consecutive nights, the underlying regulatory processes remained unspecified. To assess the role of circadian and homeostatic factors in REM sleep regulation, REM sleep was selectively deprived in healthy young adult males during a daytime sleep episode (7-15 h) after a night without sleep. Circadian REM sleep propensity is known to be high in the early morning. The number of interventions required to prevent REM sleep increased from the first to the third 2-h interval by a factor of two and then leveled off. Only a minor REM sleep rebound (11.6%) occurred in the following undisturbed recovery night. It is concluded that the limited rise of interventions during selective daytime REM sleep deprivation may be due to the declining circadian REM sleep propensity, which may partly offset the homeostatic drive and the sleep-dependent disinhibition of REM sleep. 相似文献