Search results for "RICH"
showing 10 items of 3360 documents
The Cell Cycle-Specific Growth-Inhibitory Factor Produced by Actinobacillus actinomycetemcomitans Is a Cytolethal Distending Toxin
1998
ABSTRACT Actinobacillus actinomycetemcomitans has been shown to produce a soluble cytotoxic factor(s) distinct from leukotoxin. We have identified in A. actinomycetemcomitans Y4 a cluster of genes encoding a cytolethal distending toxin (CDT). This new member of the CDT family is similar to the CDT produced by Haemophilus ducreyi . The CDT from A. actinomycetemcomitans was produced in Escherichia coli and was able to induce cell distension, growth arrest in G 2 /M phase, nucleus swelling, and chromatin fragmentation in HeLa cells. The three proteins, CDTA, -B and -C, encoded by the cdt locus were all required for toxin activity. Antiserum raised against recombinant CDTC completely inhibited …
Type III Secretion-Dependent Cell Cycle Block Caused in HeLa Cells by Enteropathogenic Escherichia coliO103
2001
ABSTRACT Rabbit enteropathogenic Escherichia coli (EPEC) O103 induces in HeLa cells an irreversible cytopathic effect characterized by the recruitment of focal adhesions, formation of stress fibers, and inhibition of cell proliferation. We have characterized the modalities of the proliferation arrest and investigated its underlying mechanisms. We found that HeLa cells that were exposed to the rabbit EPEC O103 strain E22 progressively accumulated at 4C DNA content and did not enter mitosis. A significant proportion of the cells were able to reinitiate DNA synthesis without division, leading to 8C DNA content. This cell cycle inhibition by E22 was abrogated in mutants lacking EspA, -B, and -D…
“L’intervention de Organismes intertionaux UNESCO-IAEA, dans l’etude du programme de gestion du risque eau en pays semi-aride. Project Sicile
2003
Isotopic fractionation due to N2 fixation in various grain legumes
2004
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Binding and/or hydrolysis of purine‐based nucleotides is not required for IM30 ring formation
2021
IM30, the inner membrane-associated protein of 30 kDa, is conserved in cyanobacteria and chloroplasts. Although its exact physiological function is still mysterious, IM30 is clearly essential for thylakoid membrane biogenesis and/or dynamics. Recently, a cryptic IM30 GTPase activity has been reported, albeit thus far no physiological function has been attributed to this. Yet, it is still possible that GTP binding/hydrolysis affects formation of the prototypical large homo-oligomeric IM30 ring and rod structures. Here, we show that the Synechocystis sp. PCC 6803 IM30 protein in fact is an NTPase that hydrolyzes GTP and ATP, but not CTP or UTP, with about identical rates. While IM30 forms lar…
Structural changes in Italian Late Pliocene - Pleistocene large Mammal assemblages
2001
A schematic range-chart of the late Pliocene - Pleistocene large mammal genera is presented. The main faunal events recognizable within this time span are discussed. The first faunal event occurs around the Gauss/Matuyama transition with the beginning of the middle Villafranchian characterized by the arrival of Mammuthus (Archidiskodon) and Equus (the so-called "elephant-Equus event"). The following faunal event occurs at the Plio-Pleistocene transition (the so-called "wolf event"). The latter is marked by a strong contraction in the diversity of the ruminants and by a renewal in the carnivore diversity with the arrival of social carnivores. The low diversity in ruminant assemblage persist …
Synopsis of the helminth communities of the lacertid lizards from the Balearic and Canary Islands
2012
Helminth communities of reptiles have usually been considered as depauperate and isolationist, with low abundance and species richness when compared to other vertebrates. Nevertheless there are some insular reptile populations in which this general rule is not fulfilled. In this study, we compare helminth faunas from two groups of lizards living in two different archipelagos and having different feeding habits. Lacertid lizards from Canary Islands, belonging to the endemic genus Gallotia, showed by contrast with other lacertids, a tendency to high consumption of plant matter and to rich and diverse helminth communities. Differences were found even between the lizards living in different isl…
Orthotrichum karoo (Orthotrichaceae), a new species with hyaline-awned leaves from southwestern Africa
2009
A new Orthotrichum species, 0. karoo, is described. The moss has a gametophyte similar to that of 0. diaphanum, from which it mainly differs in its peristome lacking exostome teeth. It is known from three localities in western South Africa, and from one more in southern Namibia. In all these localities it was found growing on shrubs and trees, rarely on rocks, in succulent karoo and related types of vegetation.
The tetrameric α-helical membrane protein GlpF unfolds via a dimeric folding intermediate.
2011
Many membrane proteins appear to be present and functional in higher-order oligomeric states. While few studies have analyzed the thermodynamic stability of α-helical transmembrane (TM) proteins under equilibrium conditions in the past, oligomerization of larger polytopic monomers has essentially not yet been studied. However, it is vital to study the folding of oligomeric membrane proteins to improve our understanding of the general mechanisms and pathways of TM protein folding. To investigate the folding and stability of the aquaglyceroporin GlpF from Escherichia coli, unfolding of the protein in mixed micelles was monitored by steady-state fluorescence and circular dichroism spectroscopy…