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291.
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
292.
Scorpio A Blank TE Day WA Chabot DJ 《Cellular and molecular life sciences : CMLS》2006,63(19-20):2237-2248
Anthrax has been a major cause of death in grazing animals and an occasional cause of death in humans for thousands of years. Since the late 1800s there has been an exceptional international history of anthrax vaccine development. Due to animal vaccinations, the rate of infection has dropped dramatically. Anthrax vaccines have progressed from uncharacterized whole-cell vaccines in 1881, to pXO2-negative spores in the 1930s, to culture filtrates absorbed to aluminum hydroxide in 1970, and likely to recombinant protective antigen in the near future. Each of these refinements has increased safety without significant loss of efficacy. The threat of genetically engineered, antibiotic and vaccine resistant strains of Bacillus anthracis is fueling hypothesis-driven research and global techniques--including genomics, proteomics and transposon site hybridization--to facilitate the discovery of novel vaccine targets. This review highlights historical achievements and new developments in anthrax vaccine research. 相似文献
293.
Structural and biological aspects of carotenoid cleavage 总被引:1,自引:0,他引:1
Apo-carotenoid compounds such as retinol (vitamin A) are involved in a variety of cellular processes and are found in all kingdoms of life. Instead of being synthesized from small precursors, they are commonly produced by oxidative cleavage and subsequent modification of larger carotenoid compounds. The cleavage reaction is catalyzed by a family of related enzymes, which convert specific substrate double bonds to the corresponding aldehydes or ketones. The individual family members differ in their substrate preference and the position of the cleaved double bond, giving rise to a remarkable number of products starting from a limited number of carotenoid substrate molecules. The recent determination of the structure of a member of this family has provided insight into the reaction mechanism, showing how substrate specificity is achieved. This review will focus on the biochemistry of carotenoid oxygenases and the structural determinants of the cleavage reaction. 相似文献
294.
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
295.
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
296.
297.
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
298.
Oddi S Fezza F Pasquariello N De Simone C Rapino C Dainese E Finazzi-Agrò A Maccarrone M 《Cellular and molecular life sciences : CMLS》2008,65(5):840-850
Anandamide is a lipid messenger that carries out a wide variety of biological functions. It has been suggested that anandamide
accumulation involves binding to a saturable cellular component. To identify the structure(s) involved in this process, we
analyzed the intracellular distribution of both biotinylated and radiolabeled anandamide, providing direct evidence that lipid
droplets, also known as adiposomes, constitute a dynamic reservoir for the sequestration of anandamide. In addition, confocal
microscopy and biochemical studies revealed that the anandamide-hydrolase is also spatially associated with lipid droplets,
and that cells with a larger adiposome compartment have an enhanced catabolism of anandamide. Overall, these findings suggest
that adiposomes may have a critical role in accumulating anandamide, possibly by connecting plasma membrane to internal organelles
along the metabolic route of this endocannabinoid.
S. Oddi, F. Fezza: These authors contributed equally to the study. 相似文献
299.
Protease-activated receptors (PARs) play a clear role in the burst of inflammatory reactions and immune responses. However,
for PAR-3, the most elusive member of the PAR family, the functional role is still largely unclear. It has been claimed that
PAR-3 does not signal autonomously, although the wide expression of human PAR-3 indicates its important physiological roles.
We demonstrate that in HEK-293 cells, stably transfected with human PAR-3, thrombin induced calcium signaling, IL-8 gene expression
and IL-8 release. We confirmed this finding using human lung epithelial and human astrocytoma cells that express endogenous
PAR-3. Moreover, thrombin exposure of HEK-293 cells resulted in ERK1/2 activation coinciding with IL-8 release. The effects
of thrombin were not dependent on PAR-1 activation, as confirmed by PAR-1 gene silencing. Thus, we propose that PAR-3 is able
to signal autonomously to induce IL-8 release mediated by ERK1/2 phosphorylation, which contributes actively to inflammatory
responses.
Received 9 December 2007; received after revision 16 January 2008; accepted 18 January 2008 相似文献
300.
Shin JM Vagin O Munson K Kidd M Modlin IM Sachs G 《Cellular and molecular life sciences : CMLS》2008,65(2):264-281
Inhibition of gastric acid secretion is the mainstay of the treatment of gastroesophageal reflux disease and peptic ulceration;
therapies to inhibit acid are among the best-selling drugs worldwide. Highly effective agents targeting the histamine H2 receptor
were first identified in the 1970s. These were followed by the development of irreversible inhibitors of the parietal cell
hydrogen-potassium ATPase (the proton pump inhibitors) that inhibit acid secretion much more effectively. Reviewed here are
the chemistry, biological targets and pharmacology of these drugs, with reference to their current and evolving clinical utilities.
Future directions in the development of acid inhibitory drugs include modifications of current agents and the emergence of
a novel class of agents, the acid pump antagonists.
Received 30 May 2007; received after revision 15 August 2007; accepted 13 September 2007 相似文献