Microtubules (MTs) are pivotal for numerous eukaryotic processes ranging from cellular morphogenesis, chromosome segregation to intracellular transport. Execution of these tasks requires intricate ...regulation of MT dynamics. Here, we identify a new regulator of the Schizosaccharomyces pombe MT cytoskeleton: Asp1, a member of the highly conserved Vip1 inositol polyphosphate kinase family. Inositol pyrophosphates generated by Asp1 modulate MT dynamic parameters independent of the central +TIP EB1 and in a dose-dependent and cellular-context-dependent manner. Importantly, our analysis of the in vitro kinase activities of various S. pombe Asp1 variants demonstrated that the C-terminal phosphatase-like domain of the dual domain Vip1 protein negatively affects the inositol pyrophosphate output of the N-terminal kinase domain. These data suggest that the former domain has phosphatase activity. Remarkably, Vip1 regulation of the MT cytoskeleton is a conserved feature, as Vip1-like proteins of the filamentous ascomycete Aspergillus nidulans and the distantly related pathogenic basidiomycete Ustilago maydis also affect the MT cytoskeleton in these organisms. Consistent with the role of interphase MTs in growth zone selection/maintenance, all 3 fungal systems show aspects of aberrant cell morphogenesis. Thus, for the first time we have identified a conserved biological process for inositol pyrophosphates.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Dr. Reinhard Fischer from Karlsrude Institute of Technology, Germany beautifully explains the delicate molecule dialogue during predatory interaction between nematode-trapping fungi and worms.
Von den Bedingungen, unter denen Menschen im Europa der Frühen Neuzeit Reisen unternahmen, haben wir heute kaum eine Vorstellung. Alte Reiseberichte übergehen meist Beschreibungen der ...Straßenzustände, die Unbequemlichkeit der Kutschen, die Trostlosigkeit durchquerter Landstriche - obwohl vor allem solche Umstände den Reisealltag ausmachten. Antoni Maczak lässt die Erfahrung des Unterwegsseins zwischen 1500 und 1700 lebendig werden. Er zeigt, warum man reiste, was man sich vom Reisen erhoffte und wie man durchs Reisen verändert wurde. Probleme wie die Gefahr von Kutschenunfällen, die mühsame Suche nach erträglichen Herbergen oder zuverlässigen Begleitern geraten in den Blick. Wir hören von widrigem Wetter und Gelände, wilden Tieren, marodierenden Soldaten und Wegelagerern. Uns begegnen lästige Bettgenossen und eilfertige Gastwirte, zweideutige Reisebekanntschaften und strenge Zollkontrolleure. All dies verbindet der Autor mit farbigen Porträts verschiedener Typen von Reisenden - von Bischöfen und Gesandten mit prächtigem Gefolge bis zum einsamen Pilger und zum Gelehrten, der sich aus Wissendurst und Fernweh auf den Weg macht.
Stenotrophomonas maltophilia is a highly versatile species with useful biotechnological potential but also with pathogenic properties. In light of possible differences in virulence characteristics, ...knowledge about genomic subgroups is therefore desirable. Two different genotyping methods, rep-PCR fingerprinting and partial gyrB gene sequencing were used to elucidate S. maltophilia intraspecies diversity. Rep-PCR fingerprinting revealed the presence of 12 large subgroups, while gyrB gene sequencing distinguished 10 subgroups. For 8 of them, the same strain composition was shown with both typing methods. A subset of 59 isolates representative for the gyrB groups was further investigated with regards to their pathogenic properties in a virulence model using Dictyostelium discoideum and Acanthamoeba castellanii as host organisms. A clear tendency towards accumulation of virulent strains could be observed for one group with A. castellanii and for two groups with D. discoideum. Several virulent strains did not cluster in any of the genetic groups, while other groups displayed no virulence properties at all. The amoeba pathogenicity model proved suitable in showing differences in S. maltophilia virulence. However, the model is still not sufficient to completely elucidate virulence as critical for a human host, since several strains involved in human infections did not show any virulence against amoeba.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The nervous system of metazoans is involved in host-pathogen interactions to control immune activation. In Caenorhabditis elegans, this includes sleep induction, mediated by neuropeptide-like ...proteins (NLPs), which increases the chance of survival after wounding. Here we analyzed the role of NLP-27 in the infection of C. elegans with the nematode-trapping fungus Arthrobotrys flagrans. Early responses of C. elegans were the upregulation of nlp-27, the induction of paralysis (sleep), and neurodegeneration of the mechanosensing PVD (Posterior Ventral Process D) neurons. Deletion of nlp-27 reduced neurodegeneration during fungal attack. Induction of nlp-27 was independent of the MAP kinase PMK-1, and expression of nlp-27 in the hypodermis was sufficient to induce paralysis, although NLP-27 was also upregulated in head neurons. NLP-27 contains the pentapeptide YGGYG sequence known to bind the human μ- and κ-type opioid receptors suggesting NLP-27 or peptides thereof act on opioid receptors. The opioid receptor antagonist naloxone shortened the paralysis time like overexpression of NLP-27.
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•Induction of neuropeptides during fungal infection•Induction of paralysis during fungal infection•NLP-27 enhances neurodegeneration•NLP-27 contains the YGGYG opioid motif and may be processed
Immunology; Molecular neuroscience; Neuroscience
Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between ...pro-and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Single crystals of ABW-type CsAlTiO
(
), CsFeTiO
(
), CsGaTiO
(
), and ANA-type CsTi
Si
(
) were grown and characterized by electron microprobe analyses, single-crystal X-ray diffraction, thermal ...analyses, and spindle-stage optical investigations to determine the electronic polarizability of 4-coordinated Ti
,
Ti
). The crystal structure of
was confirmed to crystallize in the highest possible topological symmetry
(
= 8.9677(2) Å,
= 5.7322(1) Å,
= 9.9612(3) Å) with tetrahedrally coordinated Al and Ti equally distributed on Wyckoff position 8i. Twinning by reticular merohedry with a twin index of 2 was observed for most of the crystals resulting in a hexagonal twin lattice (
= 11.487(3) Å,
= 8.968(2) Å) with Laue symmetry
. Refractive indices measured by immersion methods on an untwinned specimen are
= 1.716(5),
= 1.725(2), and
= 1.727(1) with 2
= 127.1(6)°. The diffraction patterns of
and
clearly showed superstructure reflections causing a symmetry lowering of index 4 with a transformation according to 2
,
,
from
to
ith
= 18.3054(7) Å,
= 5.8083(2) Å,
= 9.9938(4) Å for
, and
= 18.2921(6) Å,
= 5.7636(2) Å,
= 9.9210(3) Å for
. Refractive indices for CGT are
= 1.750(3),
= 1.772(3), and
= 1.776(2) with 2
= 132(1)°. The crystal structure of the ANA-type CsTi
Si
was confirmed to crystallize in space group
(
= 13.8333(4) Å). The extra 0.5 O atoms are needed for charge compensation and to allow the sum of electronic polarizabilities to give a total electronic polarizability calculated from the refractive index
= 1.718(4). The electronic polarizability of
Ti
was calculated from the difference between the observed total polarizabilities (derived from the mean refractive indices of
and
) and the sum of electronic polarizabilities of cations and anions omitting the polarizability of Ti resulting in
Ti
) = 5.15(5) Å
A crystal of BaCaBO3F was grown by the Czochralski method. It shows a phase transition at 242.7 °C upon cooling where the hexagonal high-temperature modification is transformed to a monoclinic ...low-temperature form (space group C2, a = 17.8779(8) Å, b = 9.0596(4) Å, c = 12.9735(5) Å, β = 118.875(13)°, V = 1840.03(22) Å3, Z = 18). The monoclinic phase has a symmetry lowered by an index of 18 relative to the hexagonal supergroup. This represents a higher symmetry than the rhombohedral model which has a symmetry of index 36 lower than the hexagonal form determined in a previous study (Li and Zeng, J. Cryst. Growth 2013, 382, 47 ). The monoclinic system is confirmed by optical investigations with a polarizing microscope showing biaxial negative character and refractive indices n x = 1.615(1), n y = 1.664(1), and n z = 1.665(1), 2V x = 10.0(2)° as measured on a microrefractometer spindle stage in immersion liquids. Electron microprobe analysis yielded a slight excess of Ba resulting in the composition Ba1.04Ca0.96BO3F corresponding to 7Ba4.7 8Ba6 9Ba4 10Ba4 7Ca17.3 3B18O54F18 in a crystal-chemical notation for the unit-cell content with the cations in their respective coordination. On the basis of this composition, the mean refractive index can be calculated from individual electronic polarizabilities of the ions resulting in <n calc> = 1.638 which is close to the observed value of <n obs> within an error of 0.5%.
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