Refine
Year of publication
- 2012 (564) (remove)
Document Type
- Article (564) (remove)
Language
- English (564) (remove)
Has Fulltext
- yes (564)
Keywords
- Cape Verde Islands (7)
- apoptosis (6)
- radiation-induced nanostructures (6)
- migration (5)
- Apoptosis (3)
- Bioenergetics (3)
- Biological invasions (3)
- Mediterranean (3)
- Membrane Proteins (3)
- Ubiquitination (3)
Institute
- Medizin (211)
- Biochemie und Chemie (57)
- Biowissenschaften (50)
- Physik (46)
- Frankfurt Institute for Advanced Studies (FIAS) (35)
- Geowissenschaften (27)
- Senckenbergische Naturforschende Gesellschaft (27)
- Institut für Ökologie, Evolution und Diversität (18)
- Biodiversität und Klima Forschungszentrum (BiK-F) (17)
- E-Finance Lab e.V. (16)
Ribosomal RNA undergoes various modifications to optimize ribosomal structure and expand the topological potential of RNA. The most common nucleotide modifications in ribosomal RNA (rRNA) are pseudouridylations and 2'-O methylations (Nm), performed by H/ACA box snoRNAs and C/D box snoRNAs, respectively. Furthermore, rRNAs of both ribosomal subunits also contain various base modifications, which are catalysed by specific enzymes. These modifications cluster in highly conserved areas of the ribosome. Although most enzymes catalysing 18S rRNA base modifications have been identified, little is known about the 25S rRNA base modifications. The m(1)A modification at position 645 in Helix 25.1 is highly conserved in eukaryotes. Helix formation in this region of the 25S rRNA might be a prerequisite for a correct topological framework for 5.8S rRNA to interact with 25S rRNA. Surprisingly, we have identified ribosomal RNA processing protein 8 (Rrp8), a nucleolar Rossman-fold like methyltransferase, to carry out the m(1)A base modification at position 645, although Rrp8 was previously shown to be involved in A2 cleavage and 40S biogenesis. In addition, we were able to identify specific point mutations in Rrp8, which show that a reduced S-adenosyl-methionine binding influences the quality of the 60S subunit. This highlights the dual functionality of Rrp8 in the biogenesis of both subunits.
An illustrated description of Withius hispanus (L. Koch, 1873) is provided based on its morphological and morphometric characters. This finding of W. hispanus is the first record of the family Withiidae in Slovakia. The present re-description of this species allows an assessment of the variability of its morphological and morphometric characters.
wo assumptions underlie current models of the geographical ranges of perennial plant species: 1. current ranges are in equilibrium with the prevailing climate, and 2. changes are attributable to changes in macroclimatic factors, including tolerance of winter cold, the duration of the growing season, and water stress during the growing season, rather than to biotic interactions. These assumptions allow model parameters to be estimated from current species ranges. Deterioration of growing conditions due to climate change, e.g. more severe drought, will cause local extinction. However, for many plant species, the predicted climate change of higher minimum temperatures and longer growing seasons means, improved growing conditions. Biogeographical models may under some circumstances predict that a species will become locally extinct, despite improved growing conditions, because they are based on an assumption of equilibrium and this forces the species range to match the species-specific macroclimatic thresholds. We argue that such model predictions should be rejected unless there is evidence either that competition influences the position of the range margins or that a certain physiological mechanism associated with the apparent improvement in growing conditions negatively affects the species performance. We illustrate how a process-based vegetation model can be used to ascertain whether such a physiological cause exists. To avoid potential modelling errors of this type, we propose a method that constrains the scenario predictions of the envelope models by changing the geographical distribution of the dominant plant functional type. Consistent modelling results are very important for evaluating how changes in species areas affect local functional trait diversity and hence ecosystem functioning and resilience, and for inferring the implications for conservation management in the face of climate change.
The apolipoprotein E4 (ApoE4) is an established risk factor for Alzheimer's disease (AD). Previous work has shown that this allele is associated with functional (fMRI) changes as well structural grey matter (GM) changes in healthy young, middle-aged and older subjects. Here, we assess the diffusion characteristics and the white matter (WM) tracts of healthy young (20-38 years) ApoE4 carriers and non-carriers. No significant differences in diffusion indices were found between young carriers (ApoE4+) and non-carriers (ApoE4-). There were also no significant differences between the groups in terms of normalised GM or WM volume. A feature selection algorithm (ReliefF) was used to select the most salient voxels from the diffusion data for subsequent classification with support vector machines (SVMs). SVMs were capable of classifying ApoE4 carrier and non-carrier groups with an extremely high level of accuracy. The top 500 voxels selected by ReliefF were then used as seeds for tractography which identified a WM network that included regions of the parietal lobe, the cingulum bundle and the dorsolateral frontal lobe. There was a non-significant decrease in volume of this WM network in the ApoE4 carrier group. Our results indicate that there are subtle WM differences between healthy young ApoE4 carriers and non-carriers and that the WM network identified may be particularly vulnerable to further degeneration in ApoE4 carriers as they enter middle and old age.
Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation.
The Strongest Meaning Hypothesis (SMH henceforth), a pragmatic principle motivated in Dalrymple et al.'s (1998) study of reciprocals, has recently been applied to problems in implicatures (Chierchia et al. to appear) and Vagueness (Cobreros et al. 2011). In this snippet, I argue that the SMH can apply to embedded sentences, which is perhaps unusual for a pragmatic principle.
In the North Atlantic, the waters surrounding the Cape Verde Islands are a "potential hot spot" for cookiecutter shark Isistius spp. interactions with cetaceans. These occurrences were recently identified by the improved efforts of researchers to document cetacean strandings in the Cape Verde archipelago, as well as by the photo identification efforts of live whales and dolphins. The documentation of individual and mass stranding events confirmed that cookiecutter shark interactions with cetaceans in Cape Verde seas are remarkably common.
Hereditary Angioedema (HAE) is a rare disease and for this reason proper diagnosis and appropriate therapy are often unknown or not available for physicians and other health care providers. For this reason we convened a group of specialists that focus upon HAE from around the world to develop not only a consensus on diagnosis and management of HAE, but to also provide evidence based grades, strength of evidence and classification for the consensus. Since both consensus and evidence grading were adhered to the document meets criteria as a guideline. The outcome of the guideline is to improve diagnosis and management of patients with HAE throughout the world and to help initiate uniform care and availability of therapies to all with the diagnosis no matter where the residence of the individual with HAE exists.
As recent newspaper headlines show the topic of patents/patent laws is still heavily disputed. In this paper I will approach this topic from a theoretical-historical and history of economic thought-perspective. In this regard I will link the patent controversy of the nineteenth century with Walter Eucken’s Ordoliberalism – a German version of neoliberalism. My paper is structured as follows: The second chapter provides the reader with a historical introduction. At the heart of this paragraph are the controversy and discourse on patent laws in nineteenth century Europe as well as the pro and contra arguments presented by the anti-patent/free-trade movement respectively by the advocates of patent protection. The focus of my paper is on the struggle for the protection of inventions and innovations in nineteenth century Germany, since Walter Eucken, main representative of the Freiburg School of Law and Economics, picks up the counter-arguments presented in the national debate and in particular by the Kongress deutscher Volkswirthe. The third chapter deals intensively with the question whether patent laws are just ‘nonsense upon stilts’ from an ordoliberal perspective. Here, Eucken’s arguments against the current patent system are elaborated in great detail. The paper ends with a summary of my main findings.
Background: Hodkin s lymphoma is one of the most frequent lymphoma in western world. Despite an overall good prognosis some patients suffer relapsing tumors which are difficult to cure. Over a long period Vitamin D has been shown to be a potential treatment for cancer. Vitamin D acts via the vitamin D receptor, a nuclear receptor, acting as an inducible transcription factor. We aimed to investigate the expression of vitamin D receptor as potential therapeutic target structure in Hodgkin s lymphoma as well as in non Hodgkin s lymphoma.
Methods: We used a panel of 193 formalin fixed tissues of lymphoma cases consisting of 55 cases of Hodgkin s lymphoma and 138 cases on several non Hodgkin s lymphoma entities.
Results: Vitamin D receptor is strongly expressed in Hodgkin s lymphoma, regardless of the subentity with an overall positivity of 80% of all Hodgkin lymphoma cases. In contrast, only about 17% of the analyzed non Hodgkin s lymphoma of B-cell origin showed positivity for vitamin D receptor. Predominant nuclear localization of vitamin D receptor in Hodgkin s lymphoma suggests activated status of the vitamin D receptor.
Conclusions: From this study, we conclude that vitamin D receptor plays a potentially important role in pathogenesis of Hodgkin s lymphoma but not in non Hodgkin s lymphoma. Further investigations of mutational status and functional studies may shed some light in functional relevance of vitamin D receptor signaling in Hodgkin s lymphoma.