Characterization of a branchial epithelial calcium channel (ECaC) in freshwater rainbow trout (Oncorhynchus mykiss)

The entry of calcium (Ca2+) through an apical membrane epithelial calcium channel (ECaC) is thought to a key step in piscine branchial Ca2+ uptake. In mammals, ECaC is a member of the transient receptor potential (TRP) gene family of which two sub-families have been identified, TRPV5 and TPRV6. In the present study we have identified a single rainbow trout (Oncorhynchus mykiss) ECaC (rtECaC) that is similar to the mammalian TRPV5 and TRPV6. Phylogenetic analysis of the protein sequence suggests that an ancestral form of the mammalian genes diverged from those in the lower vertebrates prior to the gene duplication event that gave rise to TRPV5 and TRPV6. The putative model for Ca2+ uptake in fish proposes that the mitochondria-rich cell (also termed ionocyte or chloride cell) is the predominant or exclusive site of transcellular Ca2+ movements owing to preferential localisation of ECaC to the apical membrane of these cells. However, the results of real-time PCR performed on enriched gill cell populations as well as immunocytochemistry and in situ hybridisation analysis of enriched cells, cell cultures and whole gill sections strongly suggest that ECaC is not exclusive to mitochondria-rich cells but that it is also found in pavement cells. Not only was ECaC protein localized to areas of the gill normally having few mitochondria-rich cells, but there was also no consistent co-localization of ECaC- and Na+/K+-ATPase-positive (a marker of mitochondria rich cells) cells. Taken together, the results of the present study suggest that although ECaC (mRNA and protein) does exist in trout gill, its cellular distribution is more extensive than previously thought, thus suggesting that Ca2+ uptake may not be restricted to mitochondria-rich cells as was proposed in previous models

Quantum Poincare Recurrences for Hydrogen Atom in a Microwave Field

We study the time dependence of the ionization probability of Rydberg atoms driven by a microwave field, both in classical and in quantum mechanics. The quantum survival probability follows the classical one up to the Heisenberg time and then decays algebraically as P(t) ~ 1/t. This decay law derives from the exponentially long times required to escape from some region of the phase space, due to tunneling and localization effects. We also provide parameter values which should allow to observe such decay in laboratory experiments.Comment: revtex, 4 pages, 4 figure

J-band variability of M dwarfs in the WFCAM Transit Survey

We present an analysis of the photometric variability of M dwarfs in the Wide Field Camera (WFCAM) Transit Survey. Although periodic light-curve variability in low mass stars is generally dominated by photospheric star spot activity, M dwarf variability in the J band has not been as thoroughly investigated as at visible wavelengths. Spectral type estimates for a sample of over 200 000 objects are made using spectral type-colour relations, and over 9600 dwarfs (J 0.2 mag flaring event from an M4V star in our sample.Peer reviewe

Cells migrating to sites of tissue damage in response to the danger signal HMGB1 require NF-κB activation

Tissue damage is usually followed by healing, as both differentiated and stem cells migrate to replace dead or damaged cells. Mesoangioblasts (vessel-associated stem cells that can repair muscles) and fibroblasts migrate toward soluble factors released by damaged tissue. Two such factors are high mobility group box 1 (HMGB1), a nuclear protein that is released by cells undergoing unscheduled death (necrosis) but not by apoptotic cells, and stromal derived factor (SDF)–1/CXCL12. We find that HMGB1 activates the canonical nuclear factor κB (NF-κB) pathway via extracellular signal-regulated kinase phosphorylation. NF-κB signaling is necessary for chemotaxis toward HMGB1 and SDF-1/CXCL12, but not toward growth factor platelet-derived growth factor, formyl-met-leu-phe (a peptide that mimics bacterial invasion), or the archetypal NF-κB–activating signal tumor necrosis factor α. In dystrophic mice, mesoangioblasts injected into the general circulation ingress inefficiently into muscles if their NF-κB signaling pathway is disabled. These findings suggest that NF-κB signaling controls tissue regeneration in addition to early events in inflammation

Stochastic ionization through noble tori: Renormalization results

We find that chaos in the stochastic ionization problem develops through the break-up of a sequence of noble tori. In addition to being very accurate, our method of choice, the renormalization map, is ideally suited for analyzing properties at criticality. Our computations of chaos thresholds agree closely with the widely used empirical Chirikov criterion

Report of the LHC Computing Grid Project. RTAG 12: Collaborative Tools

This document is the final report of the LHC Computing Grid (LCG) Project's Requirements and Technical Assessment Group (RTAG 12) on Collaborative Tools. It presents a summary of the requirements of the LHC collaborations for Collaborative Tools, assesses the current status of those tools in common use, discusses likely relevant future development, and provides recommendations for action by the LCG, the collaborations, and CERN for the immediate and long-term future. The requirements and assessments were assembled from formal and informal interactions between members of the RTAG, representatives of the LHC collaborations, CERN IT, and experts in the field of Collaborative Tools

Does shade improve light interception efficiency? A comparison among seedlings from shade-tolerant and -intolerant temperate deciduous tree species

• Here, we tested two hypotheses: shading increases light interception efficiency (LIE) of broadleaved tree seedlings, and shade-tolerant species exhibit larger LIEs than do shade-intolerant ones. The impact of seedling size was taken into account to detect potential size-independent effects on LIE. LIE was defined as the ratio of mean light intercepted by leaves to light intercepted by a horizontal surface of equal area. • Seedlings from five species differing in shade tolerance (Acer saccharum, Betula alleghaniensis, A. pseudoplatanus, B. pendula, Fagus sylvatica) were grown under neutral shading nets providing 36, 16 and 4% of external irradiance. Seedlings (1- and 2-year-old) were three-dimensionally digitized, allowing calculation of LIE. • Shading induced dramatic reduction in total leaf area, which was lowest in shade-tolerant species in all irradiance regimes. Irradiance reduced LIE through increasing leaf overlap with increasing leaf area. There was very little evidence of significant size-independent plasticity of LIE. • No relationship was found between the known shade tolerance of species and LIE at equivalent size and irradiance

Safety and efficacy of Taminizer D (dimethylglycine sodium salt) as a feed additive for chickens for fattening

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of Taminizer D (dimethylglycine sodium salt) as a feed additive for chickens for fattening, based on a dossier submitted for the modification of the terms of authorisation of the additive. The product is authorised in the European Union for chickens for fattening at the maximum content of 1,000 mg/kg complete feedingstuffs. The applicant proposed the introduction of an additional manufacturing process, which introduces an impurity (dimethylamino-ethanol (DMAE)) in the additive at concentrations up to 0.09%. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considered that the proposed modification would not substantially affect the previous assessment as related to the safety of the environment and the efficacy of the product. Since the safety of the active substance was established, the current assessment has dealt with the impurity DMAE. Considering the toxicological profile of DMAE, the estimated intake by the target animal and consumers, and making use of the Threshold of Toxicological Concern (TTC) approach, the Panel concluded that Taminizer D, manufactured by the DMAE route, is safe for both chickens for fattening and consumers, up to the maximum level of 1,000 mg/kg feed. The FEEDAP Panel extends its conclusions about Taminizer D produced by the original method to cover also Taminizer D produced by the new DMAE method. There is minimal risk to users from dust produced as a result of normal handling of the additive. Taminizer D is not irritant to skin but may be irritant to eyes; it is regarded as a potential skin sensitiser. The FEEDAP Panel recommended to set a specification for the DMAE content in the additive

Safety and efficacy of fumonisin esterase from Komagataella phaffii DSM 32159 as a technological feed additive for pigs and poultry

Fumonisin esterase produced from a genetically modified strain of Komagataella phaffi is intended to degrade fumonisin mycotoxins contaminants in feeds for pigs and poultry. The production strain and its recombinant genes are not present in the final product. The applicant selected 300 U/kg feed to represent a likely upper limit. This concentration showed to be safe for piglets, chickens and turkeys for fattening and laying hens; the additive is thus safe for those categories. This conclusion is extended to all pigs, chickens reared for laying and turkeys reared for breeding and extrapolated to all other poultry species for growing and laying and to minor porcine species. No evidence of mutagenicity or genotoxicity was detected and no evidence of toxicity from a repeated-dose oral toxicity study; the residue assessment did not identify any concern. The use of the additive is, thus, considered safe for consumers. The additive is not toxic by inhalation and the respiratory exposure is likely to be low; however, a risk of sensitisation via the respiratory route cannot be excluded. The additive is non-irritant to skin and eyes and is not considered a dermal sensitiser. No risks for the environment are expected following the use of the additive in feeds under the proposed condition of use. The additive has the capacity to degrade fumonisin contaminants in feed of marketable quality when used at the minimum recommended dose of 10 U/kg complete feed, as shown in studies with chickens for fattening, laying hens and weaned piglets. Since the mode of action of the additive can be reasonably assumed to be the same in animal species for which the application is made, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers the additive efficacious for all poultry and all pigs