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21.
Ferdinand Bohlmann Alfons Adler Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1982,21(6):1349-1355
The investigation of two Mikania species, both previously placed in the genus Kanimia, afforded in addition to known compounds several new germ 相似文献
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Start-up of a thermophilic upflow anaerobic sludge bed (UASB) reactor with mesophilic granular sludge 总被引:1,自引:0,他引:1
Jules B. van Lier Katja C. F. Grolle Alfons J. M. Stams Everly Conway de Macario Gatze Lettinga 《Applied microbiology and biotechnology》1992,37(1):130-135
Summary Fast start-up of thermophilic upflow anaerobic sludge bed (UASB) reactors was achieved at process temperatures of 46, 55 and 64° C, using mesophilic granular sludge as inoculum and fatty acid mixtures as feed. The start-up was brought about by increasing the temperature of mesophilic UASB reactors in a single step, which initially led to a sharp drop in the methane production rate. Thereafter, stable thermophilic methanogenesis was achieved within a period of 1 or 2 weeks depending on the temperature of operation. Mesophilic granules functioned initially as effective carrier material for thermophilic organisms. However, long-term operation led to disintegration of the granules, resulting in wash-out of thermophilic biomass. The temperature optima for acetotrophic methanogenic activity of the sludges cultivated at 46, 55 and 64° C, were similar, but differed significantly from the temperature optimum of the mesophilic inoculum. All the sludges examined were dominated by Methanothrix-like rods. These could be distinguished by antigenic fingerprinting into two subpopulations, one predominant at 36° C and the other predominant at 46° C and above.
Offprint requests to: J. B. van Lier 相似文献
24.
Ellen Cocquyt Gillian H Gile Frederik Leliaert Heroen Verbruggen Patrick J Keeling Olivier De Clerck 《BMC evolutionary biology》2010,10(1):327
Background
A non-canonical nuclear genetic code, in which TAG and TAA have been reassigned from stop codons to glutamine, has evolved independently in several eukaryotic lineages, including the ulvophycean green algal orders Dasycladales and Cladophorales. To study the phylogenetic distribution of the standard and non-canonical genetic codes, we generated sequence data of a representative set of ulvophycean green algae and used a robust green algal phylogeny to evaluate different evolutionary scenarios that may account for the origin of the non-canonical code. 相似文献25.
Temmink Ralph J. M. Dorenbosch Martijn Lamers Leon P. M. Smolders Alfons J. P. Rip Winnie Lengkeek Wouter Didderen Karin Fivash Gregory S. Bouma Tjeerd J. van der Heide Tjisse 《Hydrobiologia》2021,848(17):3987-3999
Hydrobiologia - Aquatic ecosystems provide vital services, and macrophytes play a critical role in their functioning. Conceptual models indicate that in shallow lakes, plants with different growth... 相似文献
26.
Expectation contributes to placebo and nocebo responses in Parkinson''s disease (PD). While there is evidence for expectation-induced modulations of bradykinesia, little is known about the impact of expectation on resting tremor. Subthalamic nucleus (STN) deep brain stimulation (DBS) improves cardinal PD motor symptoms including tremor whereas impairment of verbal fluency (VF) has been observed as a potential side-effect. Here we investigated how expectation modulates the effect of STN-DBS on resting tremor and its interaction with VF. In a within-subject-design, expectation of 24 tremor-dominant PD patients regarding the impact of STN-DBS on motor symptoms was manipulated by verbal suggestions (positive [placebo], negative [nocebo], neutral [control]). Patients participated with (MedON) and without (MedOFF) antiparkinsonian medication. Resting tremor was recorded by accelerometry and bradykinesia of finger tapping and diadochokinesia were assessed by a 3D ultrasound motion detection system. VF was quantified by lexical and semantic tests. In a subgroup of patients, the effect of STN-DBS on tremor was modulated by expectation, i.e. tremor decreased (placebo response) or increased (nocebo response) by at least 10% as compared to the control condition while no significant effect was observed for the overall group. Interestingly, nocebo responders in MedON were additionally characterized by significant impairment in semantic verbal fluency. In contrast, bradykinesia was not affected by expectation. These results indicate that the therapeutic effect of STN-DBS on tremor can be modulated by expectation in a subgroup of patients and suggests that tremor is also among the parkinsonian symptoms responsive to placebo and nocebo interventions. While positive expectations enhanced the effect of STN-DBS by further decreasing the magnitude of tremor, negative expectations counteracted the therapeutic effect and at the same time exacerbated a side-effect often associated with STN-DBS. The present findings underscore the potency of patients'' expectation and its relevance for therapeutic outcomes. 相似文献
27.
Margreet J. Oosterkamp Teun Veuskens Flávia Talarico Saia Sander A. B. Weelink Lynne A. Goodwin Hajnalka E. Daligault David C. Bruce John C. Detter Roxanne Tapia Cliff S. Han Miriam L. Land Loren J. Hauser Alette A. M. Langenhoff Jan Gerritse Willem J. H. van Berkel Dietmar H. Pieper Howard Junca Hauke Smidt Gosse Schraa Mark Davids Peter J. Schaap Caroline M. Plugge Alfons J. M. Stams 《PloS one》2013,8(6)
The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601T. Genes involved in cyclohexanol degradation were only found in strain K601T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far. 相似文献
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29.
Anna Lehner Viktor Magdolen Tibor Schuster Matthias Kotzsch Marion Kiechle Alfons Meindl Fred C. G. J. Sweep Paul N. Span Eva Gross 《PloS one》2013,8(4)
HTRA1 is a highly conserved serine protease which has been implicated in suppression of epithelial-to-mesenchymal-transition (EMT) and cell motility in breast cancer. Its prognostic relevance for breast cancer is unclear so far. Therefore, we evaluated the impact of HTRA1 mRNA expression on patient outcome using a cohort of 131 breast cancer patients as well as a validation cohort including 2809 publically available data sets. Additionally, we aimed at investigating for the presence of promoter hypermethylation as a mechanism for silencing the HTRA1 gene in breast tumors. HTRA1 downregulation was detected in more than 50% of the breast cancer specimens and was associated with higher tumor stage (p = 0.025). By applying Cox proportional hazard models, we observed favorable overall (OS) and disease-free survival (DFS) related to high HTRA1 expression (HR = 0.45 [CI 0.23–0.90], p = 0.023; HR = 0.55 [CI 0.32–0.94], p = 0.028, respectively), with even more pronounced impact in node-positive patients (HR = 0.21 [CI 0.07–0.63], p = 0.006; HR = 0.29 [CI 0.13–0.65], p = 0.002, respectively). Moreover, HTRA1 remained a statistically significant factor predicting DFS among established clinical parameters in the multivariable analysis. Its impact on patient outcome was independently confirmed in the validation set (for relapse-free survival (n = 2809): HR = 0.79 [CI 0.7–0.9], log-rank p = 0.0003; for OS (n = 971): HR = 0.63 [CI 0.48–0.83], log-rank p = 0.0009). In promoter analyses, we in fact detected methylation of HTRA1 in a small subset of breast cancer specimens (two out of a series of 12), and in MCF-7 breast cancer cells which exhibited 22-fold lower HTRA1 mRNA expression levels compared to unmethylated MDA-MB-231 cells. In conclusion, we show that downregulation of HTRA1 is associated with shorter patient survival, particularly in node-positive breast cancer. Since HTRA1 loss was demonstrated to induce EMT and cancer cell invasion, these patients might benefit from demethylating agents or histone deacetylase inhibitors previously reported to lead to HTRA1 upregulation, or from novel small-molecule inhibitors targeting EMT-related processes. 相似文献
30.
Basidiomycete fungi perform fertilizations by incorporation of nuclei into a monokaryotic mycelium to establish a dikaryon. The dikaryon cannot incorporate another type of nucleus, but can still act as a nucleus donor in a dikaryon–monokaryon (di–mon) mating, known as the Buller phenomenon. Previously, it has been observed that: (1) in a particular di–mon mating, one of the nuclear types of the dikaryon generally performs better as a donor than the other, and (2) when nuclei from a dikaryon are separated to form monokaryons again (dedikaryotisation), recovery of monokaryons of the two nuclear types is usually unequal. In this study, we investigated if these two observations of asymmetry are functionally related. We tested this hypothesis by performing both di–mon matings and dedikaryotisation of dikaryons derived from five different monokaryons. When a single mechanism controls both processes, the nucleus better at fertilizing a monokaryon in a Buller pairing should also be recovered upon dedikaryotisation with a higher frequency. The results showed a hierarchical structure for recovery among nuclei in dedikaryotisation, but this hierarchy did not correspond to the fertilization success during di–mon mating. These findings thus show that the mechanism causing asymmetric regeneration of nuclei, is most likely not the same as the mechanism responsible for increased chance of fertilization in di–mon matings. We discuss the complexity of the interactions that occur during di–mon matings with regards to the mating type loci. 相似文献