Search results for "actin"

Atomic Structures of Two Novel Immunoglobulin-like Domain Pairs in the Actin Cross-linking Protein Filamin

2009

Filamins are actin filament cross-linking proteins composed of an N-terminal actin-binding domain and 24 immunoglobulin-like domains (IgFLNs). Filamins interact with numerous proteins, including the cytoplasmic domains of plasma membrane signaling and cell adhesion receptors. Thereby filamins mechanically and functionally link the cell membrane to the cytoskeleton. Most of the interactions have been mapped to the C-terminal IgFLNs 16–24. Similarly, as with the previously known compact domain pair of IgFLNa20–21, the two-domain fragments IgFLNa16–17 and IgFLNa18–19 were more compact in small angle x-ray scattering analysis than would be expected for two independent domains. Solution state NM…

Precision Measurement of the First Ionization Potential of Nobelium

2018

One of the most important atomic properties governing an element's chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626 21±0.000 05  eV. This work provides a stringent benchmark for st…

First Ionization Potentials of Fm, Md, No, and Lr

2018

We report the first ionization potentials (IP1) of the heavy actinides, fermium (Fm, atomic number Z = 100), mendelevium (Md, Z = 101), nobelium (No, Z = 102), and lawrencium (Lr, Z = 103), determined using a method based on a surface ionization process coupled to an online mass separation technique in an atom-at-a-time regime. The measured IP1 values agree well with those predicted by state-of-the-art relativistic calculations performed alongside the present measurements. Similar to the well-established behavior for the lanthanides, the IP1 values of the heavy actinides up to No increase with filling up the 5f orbital, while that of Lr is the lowest among the actinides. These results clear…

Correction: Size does matter—the eco-evolutionary effects of changing body size in fish

2021

Bite marks as evidence of predation in early vertebrates

2009

Study of lifetime bite traces on agnathans and fish (or gnathostomes) from Ukraine, Estonia, Latvia and north-western and central European Russia reveals evidence of predator–prey relationships in communities of Devonian age. Numerous bite traces on skeletal parts of agnathan pteraspidiforms and psammosteiforms, placoderm arthrodires and antiarchs and sarcopterygian porolepiforms and osteolepiforms are described. Evidence of healing shows that prey organisms responded to predation by reconstruction of damaged skeletal elements. Ichthyofaunistic analysis is used to establish possible predators. The most probable predators in the Middle and Late Devonian communities are sarcopterygian porolep…

Caging techniques for field exposures of fish to chemical contaminants

2005

The article reviews current state-of-the-art to conduct fish caging as an assessment and monitoring technique in aquatic toxicology. A multitude of scientific, practical and management factors influence and may restrict how field research is carried out. For many purposes the advantages of transplant fish caging outweigh the alternative methodologies of impact studies of xenobiotics. However, besides mortality, virtually no study has evaluated the physiological consequences of caging fish. It is not known how caging itself affects the responses of fishes to chemical pollution. The used caging densities are commonly too high. However, with the aid of variables describing physiological stress…

Comparative immunologic models can enhance analyses of environmental immunotoxicity

1996

Abstract To treat immune systems and how environments affect them is a unique challenge especially when the environment is considered in its broadest perspective: internal and external. Internal focuses on relationships between immune, nervous and endocrine systems (neuroendocrine) and how they interact to maintain homeostasis. External considers physical and chemical influences that act to change the internal. Using animal models is based upon phylogeny which focuses on invertebrates, fish, amphibians, and reptiles, including mammalian results and relationships to humans. Emphasizing primitive animals is due to a growing interest in using them as models, sentinels, surrogates—predictors of…

Intention of coastal communities to support climate change mitigation policies for fish and marine ecosystem preservation

2021

Purpose This paper aims to assess the willingness of individuals living in coastal communities affected by climate change to financially support mitigation policies towards the preservation of marine ecosystems and fish resources and to identify the key drivers of their behaviour. Design/methodology/approach A survey was carried out involving 994 people living in three main Italian coastal communities. To investigate the main factors affecting Italian coastal communities’ willingness to pay (WTP) to support climate change mitigation measures to protect the marine ecosystem and fishery resources, a Tobit regression model was implemented. Findings The results show that these communities are …

The p21-activated kinase Mbt is a component of the apical protein complex in central brain neuroblasts and controls cell proliferation

2013

The final size of the central nervous system is determined by precisely controlled generation, proliferation and death of neural stem cells. We show here that the Drosophila PAK protein Mushroom bodies tiny (Mbt) is expressed in central brain progenitor cells (neuroblasts) and becomes enriched to the apical cortex of neuroblasts in a cell cycle- and Cdc42-dependent manner. Using mushroom body neuroblasts as a model system, we demonstrate that in the absence of Mbt function, neuroblasts and their progeny are correctly specified and are able to generate different neuron subclasses as in the wild type, but are impaired in their proliferation activity throughout development. In general, loss of…

An organizing region in metamorphosing hydrozoan planula larvae--stimulation of axis formation in both larval and in adult tissue.

2010

A novel wingless gene was isolated from the marine colonial hydroid Hydractinia echinata. Alignments and Bayesian inference analysis clearly assign the gene to the Wnt5A group. In line with data found for the brachyury ortholog of Hydractinia, He-wnt5A is expressed during metamorphosis in the posterior tip of the spindle-shaped planula larva, suggesting that the tip functions as a putative organizer during metamorphosis. Additionally, the outermost cells of the posterior tip are omitted from apoptosis during metamorphosis. In order to investigate this putative organizer function, we transplanted the posterior tip of metamorphosing animals into non-induced larvae and into primary polyps 24 h…