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1.
The biocontrol properties of Trichoderma species are well documented, but their effectiveness in antagonism of the problematic Sclerotium cepivorum, the causal agent of white rot in Allium species, appears limited with reports of significant control only relating to deliberately-mutated strains of Trichoderma. Our previous studies have indicated the possibility of using selected naturally-occurring strains of the antagonist in the suppression of other diseases; now in vitro and controlled environment in vivo studies have indicated that a degree of control of Onion White Rot is possible, and that the selected antagonist strains can be used in integrated treatments with Iprodione to good effect. The possible value of such treatments is considered in light of other approaches to the suppression of this continuing problem. 相似文献
2.
Pasquier CM; Promponas VI; Varvayannis NJ; Hamodrakas SJ 《Bioinformatics (Oxford, England)》1998,14(8):749-750
Summary : FT is a tool written in C++, which implements the Fourier
analysis method to locate periodicities in aminoacid or DNA sequences. It
is provided for free public use on a WWW server with a Java interface.
Availability : The server address is http://o2.db. uoa.gr/FT Contact :
shamodr@atlas.uoa.gr
相似文献
3.
Fawzi NL Fleissner MR Anthis NJ Kálai T Hideg K Hubbell WL Clore GM 《Journal of biomolecular NMR》2011,51(1-2):105-114
The measurement of (1)H transverse paramagnetic relaxation enhancement (PRE) has been used in biomolecular systems to determine long-range distance restraints and to visualize sparsely-populated transient states. The intrinsic flexibility of most nitroxide and metal-chelating paramagnetic spin-labels, however, complicates the quantitative interpretation of PREs due to delocalization of the paramagnetic center. Here, we present a novel, disulfide-linked nitroxide spin label, R1p, as an alternative to these flexible labels for PRE studies. When introduced at solvent-exposed α-helical positions in two model proteins, calmodulin (CaM) and T4 lysozyme (T4L), EPR measurements show that the R1p side chain exhibits dramatically reduced internal motion compared to the commonly used R1 spin label (generated by reacting cysteine with the spin labeling compound often referred to as MTSL). Further, only a single nitroxide position is necessary to account for the PREs arising from CaM S17R1p, while an ensemble comprising multiple conformations is necessary for those observed for CaM S17R1. Together, these observations suggest that the nitroxide adopts a single, fixed position when R1p is placed at solvent-exposed α-helical positions, greatly simplifying the interpretation of PRE data by removing the need to account for the intrinsic flexibility of the spin label. 相似文献
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5.
Benjamin T. Goult Neil Bate Nicholas J. Anthis Kate L. Wegener Alexandre R. Gingras Bipin Patel Igor L. Barsukov Iain D. Campbell Gordon C. K. Roberts David R. Critchley 《The Journal of biological chemistry》2009,284(22):15097-15106
Talin is a large flexible rod-shaped protein that activates the integrin
family of cell adhesion molecules and couples them to cytoskeletal actin. It
exists in both globular and extended conformations, and an intramolecular
interaction between the N-terminal F3 FERM subdomain and the C-terminal part
of the talin rod contributes to an autoinhibited form of the molecule. Here,
we report the solution structure of the primary F3 binding domain within the
C-terminal region of the talin rod and use intermolecular nuclear Overhauser
effects to determine the structure of the complex. The rod domain (residues
1655–1822) is an amphipathic five-helix bundle; Tyr-377 of F3 docks into
a hydrophobic pocket at one end of the bundle, whereas a basic loop in F3
(residues 316–326) interacts with a cluster of acidic residues in the
middle of helix 4. Mutation of Glu-1770 abolishes binding. The rod domain
competes with β3-integrin tails for binding to F3, and the structure of
the complex suggests that the rod is also likely to sterically inhibit binding
of the FERM domain to the membrane.The cytoskeletal protein talin has emerged as a key player, both in
regulating the affinity of the integrin family of cell adhesion molecules for
ligand (1) and in coupling
integrins to the actin cytoskeleton
(2). Thus, depletion of talin
results in defects in integrin activation
(3), integrin signaling through
focal adhesion kinase, the maintenance of cell spreading, and the assembly of
focal adhesions in cultured cells
(4). In the whole organism,
studies on the single talin gene in worms
(5) and flies
(6) show that talin is
essential for a variety of integrin-mediated events that are crucial for
normal embryonic development. In vertebrates, there are two talin
genes, and mice carrying a talin1 null allele fail to complete
gastrulation (7).
Tissue-specific inactivation of talin1 results in an inability to activate
integrins in platelets (8,
9), defects in the
membrane-cytoskeletal interface in megakaryocytes
(10), and disruption of the
myotendinous junction in skeletal muscle
(11). In contrast, mice
homozygous for a talin2 gene trap allele have no phenotype, although
the allele may be hypomorphic
(12).Recent structural studies have provided substantial insights into the
molecular basis of talin action. Talin is composed of an N-terminal globular
head (∼50 kDa) linked to an extended flexible rod (∼220 kDa). The
talin head contains a
FERM2 domain (made up
of F1, F2, and F3 subdomains) preceded by a domain referred to here as F0
(2). Studies by Wegener et
al. (30) have shown how
the F3 FERM subdomain, which has a phosphotyrosine binding domain fold,
interacts with both the canonical NPXY motif and the
membrane-proximal helical region of the cytoplasmic tails of integrin
β-subunits (13). The
latter interaction apparently activates the integrin by disrupting the salt
bridge between the integrin α- and β-subunit tails that normally
keeps integrins locked in a low affinity state. The observation that the F0
region is also important in integrin activation
(14) may be explained by our
recent finding that F0 binds, albeit with low affinity,
Rap1-GTP,3 a known
activator of integrins (15,
16). The talin rod is made up
of a series of amphipathic α-helical bundles
(17–20)
and contains a second integrin binding site (IBS2)
(21), numerous binding sites
for the cytoskeletal protein vinculin
(22), at least two actin
binding sites (23), and a
C-terminal helix that is required for assembly of talin dimers
(20,
24).Both biochemical (25) and
cellular studies (16) suggest
that the integrin binding sites in full-length talin are masked, and both
phosphatidylinositol 4,5-bisphosphate (PIP2) and Rap1 have been implicated in
exposing these sites. It is well established that some members of the FERM
domain family of proteins are regulated by a head-tail interaction
(26); gel filtration,
sedimentation velocity, and electron microscopy studies all show that talin is
globular in low salt buffers, although it is more elongated (∼60 nm in
length) in high salt (27). By
contrast, the talin rod liberated from full-length talin by calpain-II
cleavage is elongated in both buffers, indicating that the head is required
for talin to adopt a more compact state. Direct evidence for an interaction
between the talin head and rod has recently emerged from NMR studies by Goksoy
et al. (28), who
demonstrated binding of 15N-labeled talin F3 to a talin rod
fragment spanning residues 1654–2344, an interaction that was confirmed
by surface plasmon resonance (Kd = 0.57 μm)
(28). Chemical shift data also
showed that this segment of the talin rod partially masked the binding site in
F3 for the membraneproximal helix of the β3-integrin tail
(28), directly implicating the
talin head-rod interaction in regulating the integrin binding activity of
talin. Goksoy et al.
(28) subdivided the F3 binding
site in this rod fragment into two sites with higher affinity
(Kd ∼3.6 μm; residues 1654–1848)
and lower affinity (Kd ∼78 μm; residues
1984–2344). Here, we define the rod domain boundaries and determine the
NMR structure of residues 1655–1822, a five-helix bundle. We further
show that this domain binds F3 predominantly via surface-exposed residues on
helix 4, with an affinity similar to the high affinity site reported by Goksoy
et al. (28). We also
report the structure of the complex between F3 and the rod domain and show
that the latter masks the known binding site in F3 for the β3-integrin
tail and is expected to inhibit the association of the talin FERM domain with
the membrane. 相似文献
6.
7.
8.
Utility of the white gene in estimating phylogenetic relationships among mosquitoes (Diptera: Culicidae) 总被引:2,自引:0,他引:2
The utility of a nuclear protein-coding gene for reconstructing
phylogenetic relationships within the family Culicidae was explored.
Relationships among 13 species representing three subfamilies and nine
genera of Culicidae were analyzed using a 762-bp fragment of coding
sequence from the eye color gene, white. Outgroups for the study were two
species from the sister group Chaoboridae. Sequences were determined from
clone PCR products amplified from genomic DNA, and aligned following
conceptual intron splicing and amino acid translation. Third codon
positions were characterized by high levels of divergence and biased
nucleotide composition, the intensity and direction of which varied among
taxa. Equal weighting of all characters resulted in parsimony and
neighboring-joining trees at odds with the generally accepted phylogenetic
hypothesis based on morphology and rDNA sequences. The application of
differential weighting schemes recovered the traditional hypothesis, in
which the subfamily Anophelinae formed the basal clade. The subfamily
Toxorhynchitinae occupied an intermediate position, and was a sister group
to the subfamily Culicinae. Within Culicinae, the genera Sabethes and
Tripteroides formed an ancestral clade, while the Culex-Deinocerites and
Aedes- Haemagogus clades occupied increasingly derived positions in the
molecular phylogeny. An intron present in the Culicinae- Toxorhynchitinae
lineage and one outgroup taxon was absent in the basal Anophelinae lineage
and the second outgroup taxon, suggesting that intron insertions or
deletions may not always be reliable systematic characters.
相似文献
9.
Background
Adverse drug reactions (ADRs) are now recognized as an important cause of hospital admissions, with a proportion ranging from 0.9–7.9%. They also constitute a significant economic burden. We thus aimed at determining the prevalence and the economic burden of ADRs presenting to Medical Emergency Department (ED) of a tertiary referral center in India 相似文献10.
Christopher NJ Young Anthony Sinadinos Alexis Lefebvre Philippe Chan Stephen Arkle David Vaudry Dariusz C Gorecki 《Autophagy》2015,11(1):113-130
P2RX7 is an ATP-gated ion channel, which can also exhibit an open state with a considerably wider permeation. However, the functional significance of the movement of molecules through the large pore (LP) and the intracellular signaling events involved are not known. Here, analyzing the consequences of P2RX7 activation in primary myoblasts and myotubes from the Dmdmdx mouse model of Duchenne muscular dystrophy, we found ATP-induced P2RX7-dependent autophagic flux, leading to CASP3-CASP7-independent cell death. P2RX7-evoked autophagy was triggered by LP formation but not Ca2+ influx or MAPK1-MAPK3 phosphorylation, 2 canonical P2RX7-evoked signals. Phosphoproteomics, protein expression inference and signaling pathway prediction analysis of P2RX7 signaling mediators pointed to HSPA2 and HSP90 proteins. Indeed, specific HSP90 inhibitors prevented LP formation, LC3-II accumulation, and cell death in myoblasts and myotubes but not in macrophages. Pharmacological blockade or genetic ablation of p2rx7 also proved protective against ATP-induced death of muscle cells, as did inhibition of autophagy with 3-MA. The functional significance of the P2RX7 LP is one of the great unknowns of purinergic signaling. Our data demonstrate a novel outcome—autophagy—and show that molecules entering through the LP can be targeted to phagophores. Moreover, we show that in muscles but not in macrophages, autophagy is needed for the formation of this LP. Given that P2RX7-dependent LP and HSP90 are critically interacting in the ATP-evoked autophagic death of dystrophic muscles, treatments targeting this axis could be of therapeutic benefit in this debilitating and incurable form of muscular dystrophy. 相似文献