Search results for "ddc:570"
showing 10 items of 132 documents
Methionine in a protein hydrophobic core drives tight interactions required for assembly of spider silk
2019
Web spiders connect silk proteins, so-called spidroins, into fibers of extraordinary toughness. The spidroin N-terminal domain (NTD) plays a pivotal role in this process: it polymerizes spidroins through a complex mechanism of dimerization. Here we analyze sequences of spidroin NTDs and find an unusually high content of the amino acid methionine. We simultaneously mutate all methionines present in the hydrophobic core of a spidroin NTD from a nursery web spider’s dragline silk to leucine. The mutated NTD is strongly stabilized and folds at the theoretical speed limit. The structure of the mutant is preserved, yet its ability to dimerize is substantially impaired. We find that side chains of…
Species–area relationships in continuous vegetation: Evidence from Palaearctic grasslands
2019
Aim Species-area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas, power laws best represent SARs. Yet, it remains unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape. Location Palaearctic grasslands and other non-forested habitats. Taxa Vascular plants, bryophytes and lichens. Methods We used the GrassPlot database, containing standardized vegetation-plot data from vascular plants, bryophytes and lichens spanning a wide range of grassland types throu…
Can fruiting plants control animal behaviour and seed dispersal distance?
2015
In an Afrotropical forest, we tested the hypothesis that fleshy-fruit plants with interspecific dif-ferences in fruit quality and quantity affect ranging behaviour of their seed dispersal vector. Iffruiting plants could affect their dispersal vector, the plants also affect their seed dispersal distanceand eventually their plant population biology. From 2007 to 2011, we measured seed transportby georeference daily bonobo group movements via GPS. Seed dispersal distance was estimatedwith mechanistic model, using 1200 georeferenced dispersal events and the average seed transittime through bonobo (24.00 h). We compared dissemination for eight plant species that deal withthis trade-off: attracti…
Factors controlling hydrochemical and trophic state variables in 86 shallow lakes in Europe
2003
In order to disentangle the causes of variations in water chemistry among European shallow lakes, we performed standardised sampling programs in 86 lakes along a latitudinal gradient from southern Spain to northern Sweden. Lakes with an area of 0.1 to 27 000 ha and mean depth of 0.4–5.6 m located in low to high altitudes were investigated within the EC project ECOFRAME 1–4 times during June–October 2000–2001. Several variables like conductivity, alkalinity, abundance of submerged plants, concentrations of suspended solids, total nitrogen and phosphorus were latitude-dependent decreasing from south to north. Secchi depth, concentrations of total nitrogen, total phosphorus, suspended solids, …
Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicl…
2018
The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines fo…
Optomotor-blind negatively regulates Drosophila eye development by blocking Jak/STAT signaling
2015
Organ formation requires a delicate balance of positive and negative regulators. In Drosophila eye development, wingless (wg) is expressed at the lateral margins of the eye disc and serves to block retinal development. The T-box gene optomotor-blind (omb) is expressed in a similar pattern and is regulated by Wg. Omb mediates part of Wg activity in blocking eye development. Omb exerts its function primarily by blocking cell proliferation. These effects occur predominantly in the ventral margin. Our results suggest that the primary effect of Omb is the blocking of Jak/STAT signaling by repressing transcription of upd which encodes the Jak receptor ligand Unpaired.
Genome-wide association study and mouse expression data identify a highly conserved 32 kb intergenic region between WNT3 and WNT9b as possible suscep…
2014
Item does not contain fulltext Bladder exstrophy-epispadias complex (BEEC), the severe end of the urorectal malformation spectrum, has a profound impact on continence as well as sexual and renal functions. It is widely accepted that for the majority of cases the genetic basis appears to be multifactorial. Here, we report the first study which utilizes genome-wide association methods to analyze a cohort comprising patients presenting the most common BEEC form, classic bladder exstrophy (CBE), to identify common variation associated with risk for isolated CBE. We employed discovery and follow-up samples comprising 218 cases/865 controls and 78 trios in total, all of European descent. Our disc…
Analysis of the Cellular Roles of MOCS3 Identifies a MOCS3-Independent Localization of NFS1 at the Tips of the Centrosome
2019
The deficiency of the molybdenum cofactor (Moco) is an autosomal recessive disease, which leads to the loss of activity of all molybdoenzymes in humans with sulfite oxidase being the essential protein. Moco deficiency generally results in death in early childhood. Moco is a sulfur-containing cofactor synthesized in the cytosol with the sulfur being provided by a sulfur relay system composed of the L-cysteine desulfurase NFS1, MOCS3, and MOCS2A. Human MOCS3 is a dual-function protein that was shown to play an important role in Moco biosynthesis and in the mcm(5)s(2) U thio modifications of nucleosides in cytosolic tRNAs for Lys, Gln, and Glu. In this study, we constructed a homozygous MOCS3 …
Genomic divergence landscape in recurrently hybridizing Chironomus sister taxa suggests stable steady state between mutual gene flow and isolation
2021
Abstract Divergence is mostly viewed as a progressive process often initiated by selection targeting individual loci, ultimately resulting in ever increasing genomic isolation due to linkage. However, recent studies show that this process may stall at intermediate stable equilibrium states without achieving complete genomic isolation. We tested the extent of genomic isolation between two recurrently hybridizing nonbiting midge sister taxa, Chironomus riparius and Chironomus piger, by analyzing the divergence landscape. Using a principal component‐based method, we estimated that only about 28.44% of the genomes were mutually isolated, whereas the rest was still exchanged. The divergence land…
Pathophysiology of ageing, longevity and age related diseases
2007
Abstract On April 18, 2007 an international meeting on Pathophysiology of Ageing, Longevity and Age-Related Diseases was held in Palermo, Italy. Several interesting topics on Cancer, Immunosenescence, Age-related inflammatory diseases and longevity were discussed. In this report we summarize the most important issues. However, ageing must be considered an unavoidable end point of the life history of each individual, nevertheless the increasing knowledge on ageing mechanisms, allows envisaging many different strategies to cope with, and delay it. So, a better understanding of pathophysiology of ageing and age-related disease is essential for giving everybody a reasonable chance for living a …