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401.
Consonni C Humphry ME Hartmann HA Livaja M Durner J Westphal L Vogel J Lipka V Kemmerling B Schulze-Lefert P Somerville SC Panstruga R 《Nature genetics》2006,38(6):716-720
In the fungal phylum Ascomycota, the ability to cause disease in plants and animals has been gained and lost repeatedly during phylogenesis. In monocotyledonous barley, loss-of-function mlo alleles result in effective immunity against the Ascomycete Blumeria graminis f. sp. hordei, the causal agent of powdery mildew disease. However, mlo-based disease resistance has been considered a barley-specific phenomenon to date. Here, we demonstrate a conserved requirement for MLO proteins in powdery mildew pathogenesis in the dicotyledonous plant species Arabidopsis thaliana. Epistasis analysis showed that mlo resistance in A. thaliana does not involve the signaling molecules ethylene, jasmonic acid or salicylic acid, but requires a syntaxin, glycosyl hydrolase and ABC transporter. These findings imply that a common host cell entry mechanism of powdery mildew fungi evolved once and at least 200 million years ago, suggesting that within the Erysiphales (powdery mildews) the ability to cause disease has been a stable trait throughout phylogenesis. 相似文献
402.
Kraytsberg Y Kudryavtseva E McKee AC Geula C Kowall NW Khrapko K 《Nature genetics》2006,38(5):518-520
Using a novel single-molecule PCR approach to quantify the total burden of mitochondrial DNA (mtDNA) molecules with deletions, we show that a high proportion of individual pigmented neurons in the aged human substantia nigra contain very high levels of mtDNA deletions. Molecules with deletions are largely clonal within each neuron; that is, they originate from a single deleted mtDNA molecule that has expanded clonally. The fraction of mtDNA deletions is significantly higher in cytochrome c oxidase (COX)-deficient neurons than in COX-positive neurons, suggesting that mtDNA deletions may be directly responsible for impaired cellular respiration. 相似文献
403.
Based on the classification of bacterial lipolytic enzymes, family I.3 lipase is a member of the large group of Gram-negative
bacterial true lipases. This lipase family is distinguished from other families not only by the amino acid sequence, but also
by the secretion mechanism. Lipases of family I.3 are secreted via the well-known type I secretion system. Like most of proteins
secreted via this system, family I.3 lipases are composed of two domains with distinct yet related functions. Recent years
have seen an increasing amount of research on this lipase family, in terms of isolation, secretion mechanism, as well as biochemical
and biophysical studies. This review describes our current knowledge on the structure-function relationships of family I.3
lipase, with an emphasis on its secretion mechanism.
Received 18 April 2006; received after revision 3 July 2006; accepted 24 August 2006 相似文献
404.
McCarroll SA Hadnott TN Perry GH Sabeti PC Zody MC Barrett JC Dallaire S Gabriel SB Lee C Daly MJ Altshuler DM;International HapMap Consortium 《Nature genetics》2006,38(1):86-92
The locations and properties of common deletion variants in the human genome are largely unknown. We describe a systematic method for using dense SNP genotype data to discover deletions and its application to data from the International HapMap Consortium to characterize and catalogue segregating deletion variants across the human genome. We identified 541 deletion variants (94% novel) ranging from 1 kb to 745 kb in size; 278 of these variants were observed in multiple, unrelated individuals, 120 in the homozygous state. The coding exons of ten expressed genes were found to be commonly deleted, including multiple genes with roles in sex steroid metabolism, olfaction and drug response. These common deletion polymorphisms typically represent ancestral mutations that are in linkage disequilibrium with nearby SNPs, meaning that their association to disease can often be evaluated in the course of SNP-based whole-genome association studies. 相似文献
405.
Niimura N Arai S Kurihara K Chatake T Tanaka I Bau R 《Cellular and molecular life sciences : CMLS》2006,63(3):285-300
Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins, a technique complimentary to ultra-high-resolution [1, 2] X-ray diffraction. Three different types of neutron diffractometers for biological macromolecules have been constructed in Japan, France and the United States, and they have been used to determine the crystal structures of proteins up to resolution limits of 1.5-2.5 A. Results relating to hydrogen positions and hydration patterns in proteins have been obtained from these studies. Examples include the geometrical details of hydrogen bonds, H/D exchange in proteins and oligonucleotides, the role of hydrogen atoms in enzymatic activity and thermostability, and the dynamical behavior of hydration structures, all of which have been extracted from these structural results and reviewed. Other techniques, such as the growth of large single crystals, the preparation of fully deuterated proteins, the use of cryogenic techniques, and a data base of hydrogen and hydration in proteins, will be described. 相似文献
406.
407.
Gereben B Zeöld A Dentice M Salvatore D Bianco AC 《Cellular and molecular life sciences : CMLS》2008,65(4):570-590
The thyroid hormone plays a fundamental role in the development, growth, and metabolic homeostasis in all vertebrates by affecting
the expression of different sets of genes. A group of thioredoxin fold-containing selenoproteins known as deiodinases control
thyroid hormone action by activating or inactivating the precursor molecule thyroxine that is secreted by the thyroid gland.
These pathways ensure regulation of the availability of the biologically active molecule T3, which occurs in a time-and tissue-specific
fashion. In addition, because cells and plasma are in equilibrium and deiodination affects central thyroid hormone regulation,
these local deiodinase-mediated events can also affect systemic thyroid hormone economy, such as in the case of non-thyroidal
illness. Heightened interest in the field has been generated following the discovery that the deiodinases can be a component
in both the Sonic hedgehog signaling pathway and the TGR-5 signaling cascade, a G-protein-coupled receptor for bile acids.
These new mechanisms involved in deiodinase regulation indicate that local thyroid hormone activation and inactivation play
a much broader role than previously thought.
Received 29 August 2007; received after revision 11 October 2007; accepted 16 October 2007 相似文献
408.
Lubelski J Rink R Khusainov R Moll GN Kuipers OP 《Cellular and molecular life sciences : CMLS》2008,65(3):455-476
This review discusses the state-of-the-art in molecular research on the most prominent and widely applied lantibiotic, i.e., nisin. The developments in understanding its complex biosynthesis and mode of action are highlighted. Moreover, novel applications
arising from engineering either nisin itself, or from the construction of totally novel dehydrated and/or lanthionine-containing
peptides with desired bioactivities are described. Several challenges still exist in understanding the immunity system and
the unique multiple reactions occurring on a single substrate molecule, carried out by the dehydratase NisB and the cyclization
enzyme NisC. The recent elucidation of the 3-D structure of NisC forms the exciting beginning of further 3-D-structure determinations
of the other biosynthetic enzymes, transporters and immunity proteins. Advances in achieving in vitro activities of lanthionine-forming enzymes will greatly enhance our understanding of the molecular characteristics of the
biosynthesis process, opening up new avenues for developing unique and novel biocatalytic processes.
Received 9 April 2007; received after revision 31 August 2007; accepted 28 September 2007 相似文献
409.
Navarro S Aleu J Jiménez M Boix E Cuchillo CM Nogués MV 《Cellular and molecular life sciences : CMLS》2008,65(2):324-337
Human eosinophil cationic protein (ECP)/ ribonuclease 3 (RNase 3) is a protein secreted from the secondary granules of activated
eosinophils. Specific properties of ECP contribute to its cytotoxic activities associated with defense mechanisms. In this
work the ECP cytotoxic activity on eukaryotic cell lines is analyzed. The ECP effects begin with its binding and aggregation
to the cell surface, altering the cell membrane permeability and modifying the cell ionic equilibrium. No internalization
of the protein is observed. These signals induce cell-specific morphological and biochemical changes such as chromatin condensation,
reversion of membrane asymmetry, reactive oxygen species production and activation of caspase-3-like activity and, eventually,
cell death. However, the ribonuclease activity component of ECP is not involved in this process as no RNA degradation is observed.
In summary, the cytotoxic effect of ECP is attained through a mechanism different from that of other cytotoxic RNases and
may be related with the ECP accumulation associated with the inflammatory processes, in which eosinophils are present.
Received 26 October 2007; accepted 23 November 2007 相似文献
410.
Cohausz O Blenn C Malanga M Althaus FR 《Cellular and molecular life sciences : CMLS》2008,65(4):644-655
Poly(ADP-ribose) (PAR) has been identified as a DNA damage-inducible cell death signal upstream of apoptosis-inducing factor
(AIF). PAR causes the translocation of AIF from mitochondria to the nucleus and triggers cell death. In living cells, PAR
molecules are subject to dynamic changes pending on internal and external stress factors. Using RNA interference (RNAi), we
determined the roles of poly(ADP-ribose) polymerases-1 and -2 (PARP-1, PARP-2) and poly(ADP-ribose) glycohydrolase (PARG),
the key enzymes configuring PAR molecules, in cell death induced by an alkylating agent. We found that PARP-1, but not PARP-2
and PARG, contributed to alkylation-induced cell death. Likewise, AIF translocation was only affected by PARP-1. PARP-1 seems
to play a major role configuring PAR as a death signal involving AIF translocation regardless of the death pathway involved.
Received 7 November 2007; received after revision 19 December 2007; accepted 21 December 2007
O. Cohausz, C. Blenn: These two authors contributed equally to this work. 相似文献