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1.
We isolated a Tn5 insertion mutant of Rhodobacter capsulatus which requires biotin for growth. Crossfeeding studies with Escherichia coli bio mutants indicated that the insertion is in the bioB gene. A cosmid that complements the bioB insertion was isolated, and the bioB gene was localized to a 2.85-kilobase EcoRI-PstI fragment. 相似文献
2.
Blanca Arango-Gonzalez Dragana Trifunovi? Ayse Sahaboglu Katharina Kranz Stylianos Michalakis Pietro Farinelli Susanne Koch Fred Koch Sandra Cottet Ulrike Janssen-Bienhold Karin Dedek Martin Biel Eberhart Zrenner Thomas Euler Per Ekstr?m Marius Ueffing Fran?ois Paquet-Durand 《PloS one》2014,9(11)
Cell death in neurodegenerative diseases is often thought to be governed by apoptosis; however, an increasing body of evidence suggests the involvement of alternative cell death mechanisms in neuronal degeneration. We studied retinal neurodegeneration using 10 different animal models, covering all major groups of hereditary human blindness (rd1, rd2, rd10, Cngb1 KO, Rho KO, S334ter, P23H, Cnga3 KO, cpfl1, Rpe65 KO), by investigating metabolic processes relevant for different forms of cell death. We show that apoptosis plays only a minor role in the inherited forms of retinal neurodegeneration studied, where instead, a non-apoptotic degenerative mechanism common to all mutants is of major importance. Hallmark features of this pathway are activation of histone deacetylase, poly-ADP-ribose-polymerase, and calpain, as well as accumulation of cyclic guanosine monophosphate and poly-ADP-ribose. Our work thus demonstrates the prevalence of alternative cell death mechanisms in inherited retinal degeneration and provides a rational basis for the design of mutation-independent treatments. 相似文献
3.
Specific root length as an indicator of environmental change 总被引:4,自引:0,他引:4
I. Ostonen Ü. Püttsepp C Biel O. Alberton M. R. Bakker K. Lõhmus 《Plant biosystems》2013,147(3):426-442
Abstract Specific root length (SRL, m g?1) is probably the most frequently measured morphological parameter of fine roots. It is believed to characterize economic aspects of the root system and to be indicative of environmental changes. The main objectives of this paper were to review and summarize the published SRL data for different tree species throughout Europe and to assess SRL under varying environmental conditions. Meta-analysis was used to summarize the response of SRL to the following manipulated environmental conditions: fertilization, irrigation, elevated temperature, elevated CO2, Al-stress, reduced light, heavy metal stress and physical disturbance of soil. SRL was found to be strongly dependent on the fine root classes, i.e. on the ectomycorrhizal short roots (ECM), and on the roots <0.5 mm, <1 mm, <2 mm and 1 – 2 mm in diameter SRL was largest for ECM and decreased with increasing diameter. Changes in soil factors influenced most strongly the SRL of ECM and roots <0.5 mm. The variation in the SRL components, root diameter and root tissue density, and their impact on the SRL value were computed. Meta-analyses showed that SRL decreased significantly under fertilization and Al-stress; it responded negatively to reduced light, elevated temperature and CO2. We suggest that SRL can be used successfully as an indicator of nutrient availability to trees in experimental conditions. 相似文献
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Freise D Held B Wissenbach U Pfeifer A Trost C Himmerkus N Schweig U Freichel M Biel M Hofmann F Hoth M Flockerzi V 《The Journal of biological chemistry》2000,275(19):14476-14481
In skeletal muscle the oligomeric alpha(1S), alpha(2)/delta-1 or alpha(2)/delta-2, beta1, and gamma1 L-type Ca(2+) channel or dihydropyridine receptor functions as a voltage sensor for excitation contraction coupling and is responsible for the L-type Ca(2+) current. The gamma1 subunit, which is tightly associated with this Ca(2+) channel, is a membrane-spanning protein exclusively expressed in skeletal muscle. Previously, heterologous expression studies revealed that gamma1 might modulate Ca(2+) currents expressed by the pore subunit found in heart, alpha(1C), shifting steady state inactivation, and increasing current amplitude. To determine the role of gamma1 assembled with the skeletal subunit composition in vivo, we used gene targeting to establish a mouse model, in which gamma1 expression is eliminated. Comparing litter-matched mice with control mice, we found that, in contrast to heterologous expression studies, the loss of gamma1 significantly increased the amplitude of peak dihydropyridine-sensitive I(Ca) in isolated myotubes. Whereas the activation kinetics of the current remained unchanged, inactivation of the current was slowed in gamma1-deficient myotubes and, correspondingly, steady state inactivation of I(Ca) was shifted to more positive membrane potentials. These results indicate that gamma1 decreases the amount of Ca(2+) entry during stimulation of skeletal muscle. 相似文献
8.
Channels directly gated by cyclic nucleotides (CNG channels) are important cellular switches that mediate influx of Na+ and Ca2+ in response to increases in the intracellular concentration of cAMP and cGMP. In photoreceptors and olfactory receptor neurons,
these channels serve as final targets for cGMP and cAMP signaling pathways that are initiated by the absorption of photons
and the binding of odorants, respectively. CNG channels have been also found in other types of neurons and in non-excitable
cells. However, in most of these cells, the physiological role of CNG channels has yet to be determined. CNG channels have
a complex heteromeric structure. The properties of individual subunits that assemble in specific stoichiometries to the native
channels have been extensively investigated in heterologous expression systems. Recently, mutations in human CNG channel genes
leading to inherited diseases (so-called channelopathies) have been functionally characterized. Moreover, mouse knockout models
were generated to define the role of CNG channel proteins in vivo. In this review, we will summarize recent insights into
the physiological and pathophysiological role of CNG channel proteins that have emerged from genetic studies in mice and humans. 相似文献
9.
Expression of Ca2+-permeable two-pore channels rescues NAADP signalling in TPC-deficient cells 下载免费PDF全文
Margarida Ruas Lianne C Davis Cheng-Chang Chen Anthony J Morgan Kai-Ting Chuang Timothy F Walseth Christian Grimm Clive Garnham Trevor Powell Nick Platt Frances M Platt Martin Biel Christian Wahl-Schott John Parrington Antony Galione 《The EMBO journal》2015,34(13):1743-1758
The second messenger NAADP triggers Ca2+ release from endo-lysosomes. Although two-pore channels (TPCs) have been proposed to be regulated by NAADP, recent studies have challenged this. By generating the first mouse line with demonstrable absence of both Tpcn1 and Tpcn2 expression (Tpcn1/2−/−), we show that the loss of endogenous TPCs abolished NAADP-dependent Ca2+ responses as assessed by single-cell Ca2+ imaging or patch-clamp of single endo-lysosomes. In contrast, currents stimulated by PI(3,5)P2 were only partially dependent on TPCs. In Tpcn1/2−/− cells, NAADP sensitivity was restored by re-expressing wild-type TPCs, but not by mutant versions with impaired Ca2+-permeability, nor by TRPML1. Another mouse line formerly reported as TPC-null likely expresses truncated TPCs, but we now show that these truncated proteins still support NAADP-induced Ca2+ release. High-affinity [32P]NAADP binding still occurs in Tpcn1/2−/− tissue, suggesting that NAADP regulation is conferred by an accessory protein. Altogether, our data establish TPCs as Ca2+-permeable channels indispensable for NAADP signalling. 相似文献
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