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101.
Edita Tylov�� Lenka Steinbachov�� Ale? Soukup V��t Gloser Olga Votrubov�� 《Hydrobiologia》2013,700(1):141-155
Phragmites australis and Glyceria maxima are fast-growing littoral grasses often competing for similar wetland habitats. Eutrophication affects their competitiveness, but the outcome is not generally predictable due to the complexity of interrelated factors. We hypotheses that pore water N:P and NH4 +:NO3 ? modify their growth and metabolic responses to the trophic status of the habitat. The hypothesis was tested under standardized conditions of long-term sand cultures. Application of N?+?P up to extreme levels in combination with N:P?<?10 and NH4 +:NO3 ??<?1 triggered positive growth response in both species. In contrast, similar N levels applied in N:P?>?90 and NH4 +:NO3 ??=?4 caused lower productivity, changes in resource allocation, morphology and metabolic relations (e.g. high shoot density, low shoot diameters and heights, reduced root and rhizome growth). Observed signs of stress resembled the factors associated with the reed retreat at the die-back sites. Unbalanced N levels obviously alter plant susceptibility to stresses (altering, e.g. ventilation efficiency, plant anchorage or below-ground storage capacity). The positive effect of sufficient P supply was pronounced in Glyceria. It might therefore favour Glyceria in competition with Phragmites at highly fertile habitats rich in P. 相似文献
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Helices are the most common elements of RNA secondary structure. Despite intensive investigations of various types of RNAs, the evolutionary history of the formation of new helices (novel helical structures) remains largely elusive. Here, by studying the nuclear ribosomal Internal Transcribed Spacer 2 (ITS2), a fast-evolving part of the eukaryotic nuclear ribosomal operon, we identify two possible types of helix formation: one type is “dichotomous helix formation”—transition from one large helix to two smaller helices by invagination of the apical part of a helix, which significantly changes the shape of the original secondary structure but does not increase its complexity (i.e., the total length of the RNA). An alternative type is “lateral helix formation”—origin of an extra helical region by the extension of a bulge loop or a spacer in a multi-helix loop of the original helix, which does not disrupt the pre-existing structure but increases RNA size. Moreover, we present examples from the RNA sequence literature indicating that both types of helix formation may have implications for RNA evolution beyond ITS2. 相似文献
104.
Helena Fingerova Ivana Oborna Jiri Novotny Magda Svobodova Jana Brezinova Lenka Radova 《Reproductive biology and endocrinology : RB&E》2009,7(1):118-6
Background
It is generally accepted that oxidative stress is an important factor in male infertility because it may impair the physiological function of spermatozoa at the molecular level. Nevertheless, although several approaches have been reported, the imbalance between production of reactive oxygen species (ROS) and activity of the antioxidant defense system in semen is difficult to investigate and remains poorly understood. 相似文献105.
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Qingqing Zhou Tristan A. Reekie Ramzi H. Abbassi Dinesh Indurthi Venkata Josep S. Font Renae M. Ryan Lenka Munoz Michael Kassiou 《Bioorganic & medicinal chemistry》2018,26(22):5852-5869
Dual-specificity tyrosine phosphorylation-related kinase 1A (DYRK1A) is a dual-specificity protein kinase that catalyses phosphorylation and autophosphorylation. Higher DYRK1A expression correlates with cancer, in particular glioblastoma present within the brain. We report here the synthesis and biological evaluation of new heterocyclic diphenolic derivatives designed as novel DYRK1A inhibitors. The generation of these heterocycles such as benzimidazole, imidazole, naphthyridine, pyrazole-pyridines, bipyridine, and triazolopyrazines was made based on the structural modification of the lead DANDY and tested for their ability to inhibit DYRK1A. None of these derivatives showed significant DYRK1A inhibition but provide valuable knowledge around the importance of the 7-azaindole moiety. These data will be of use for developing further structure-activity relationship studies to improve the selective inhibition of DYRK1A. 相似文献
107.
Lenka Procházková Daniel Remias Andreas Holzinger Tomáš Řezanka Linda Nedbalová 《欧洲藻类学杂志》2018,53(2):230-243
Based on analyses of multiple molecular markers (18S rDNA, ITS1, ITS2 rDNA, rbcL), an alga that causes red snow on the melting ice cover of a high-alpine lake in the High Tatras (Slovakia) was shown to be identical with Chlainomonas sp. growing in a similar habitat in the Tyrolean Alps (Austria). Both populations consisted mostly of smooth-walled quadriflagellates. They occurred in slush, and shared similar photosynthetic performances (photoinhibition above 1300 µmol photons m–2 s–1), very high levels of polyunsaturated fatty acids (PUFA, 64% and 74% respectively) and abundant astaxanthin accumulation, comparable to the red spores of Chlamydomonas nivalis (Bauer) Wille. Physiological differences between the Slovak and Austrian populations included higher levels of α-tocopherol and a 13Z-isomer of astaxanthin in the former. High accumulation of secondary pigments in the Slovak population probably reflected harsher environmental conditions, since the collection was made later in the growing season when cells were exposed to higher irradiance at the surface. Using a polyphasic approach, we compared Chlainomonas sp. with Chlamydomonas nivalis. The latter causes ?conventional? red snow, and shows high photophysiological plasticity, with high efficiency under low irradiance and no photoinhibition up to 2000 µmol photons m–2 s–1. Its PUFA content was significantly lower (50%). An annual cycle of lake-to-snow colonization by Chlainomonas sp. from slush layers deeper in the ice cover is proposed. Our results point to an ecologically highly specialized cryoflora species, whose global distribution is likely to be more widespread than previously assumed. 相似文献
108.
Lenka Kramná Pavel Dřevínek Jake Lin Michal Kulich Ondrej Cinek 《Folia microbiologica》2018,63(2):237-248
The lung in cystic fibrosis (CF) is home to numerous pathogens that shorten the lives of patients. The aim of the present study was to assess changes in the lung bacteriome following antibiotic therapy targeting Pseudomonas aeruginosa in children with CF. The study included nine children (9–18 years) with CF who were treated for their chronic or intermittent positivity for Pseudomonas aeruginosa. The bacteriomes were determined in 16 pairs of sputa collected at the beginning and at the end of a course of intravenous antibiotic therapy via deep sequencing of the variable region 4 of the 16S rRNA gene, and the total bacterial load and selected specific pathogens were assessed using quantitative real-time PCR. The effect of antipseudomonal antibiotics was observable as a profound decrease in the total 16S rDNA load (p = 0.001) as well as in a broad range of individual taxa including Staphylococcus aureus (p = 0.03) and several members of the Streptococcus mitis group (S. oralis, S. mitis, and S. infantis) (p = 0.003). Improvements in forced expiratory volume (FEV1) were associated with an increase in Granulicatella sp. (p = 0.004), whereas a negative association was noted between the total bacterial load and white blood cell count (p = 0.007). In conclusion, the data show how microbial communities differ in reaction to antipseudomonal treatment, suggesting that certain rare species may be associated with clinical parameters. Our work also demonstrates the utility of absolute quantification of bacterial load in addition to the 16S rDNA profiling. 相似文献
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