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161.
Bezerra GA Oliveira TM Moreno FB de Souza EP da Rocha BA Benevides RG Delatorre P de Azevedo WF Cavada BS 《Journal of structural biology》2007,160(2):168-176
Plant lectins, especially those purified from species of the Leguminosae family, represent the best studied group of carbohydrate-binding proteins. The legume lectins from Diocleinae subtribe are highly similar proteins that present significant differences in the potency/efficacy of their biological activities. The structural studies of the interactions between lectins and sugars may clarify the origin of the distinct biological activities observed in this high similar class of proteins. In this way, this work presents a crystallographic study of the ConM and CGL (agglutinins from Canavalia maritima and Canavalia gladiata, respectively) in the following complexes: ConM/CGL:Man(alpha1-2)Man(alpha1-O)Me, ConM/CGL:Man(alpha1-3)Man(alpha1-O)Me and ConM/CGL:Man(alpha1-4)Man(alpha1-O)Me, which crystallized in different conditions and space group from the native proteins. The structures were solved by molecular replacement, presenting satisfactory values for R(factor) and R(free). Comparisons between ConM, CGL and ConA (Canavalia ensiformis lectin) binding mode with the dimannosides in subject, presented different interactions patterns, which may account for a structural explanation of the distincts biological properties observed in the lectins of Diocleinae subtribe. 相似文献
162.
Sánchez-Alcázar JA Rodríguez-Hernández A Cordero MD Fernández-Ayala DJ Brea-Calvo G Garcia K Navas P 《Apoptosis : an international journal on programmed cell death》2007,12(7):1195-1208
It has recently been shown that the microtubule cytoskeleton is reformed during the execution phase of apoptosis. We demonstrate
that this microtubule reformation occurs in many cell types and under different apoptotic stimuli. We confirm that the apoptotic
microtubule network possesses a novel organization, whose nucleation appears independent of conventional γ-tubulin ring complex
containing structures. Our analysis suggests that microtubules are closely associated with the plasma membrane, forming a
cortical ring or cellular “cocoon”. Concomitantly other components of the cytoskeleton, such as actin and cytokeratins disassemble.
We found that colchicine-mediated disruption of apoptotic microtubule network results in enhanced plasma membrane permeability
and secondary necrosis, suggesting that the reformation of a microtubule cytoskeleton plays an important role in preserving
plasma membrane integrity during apoptosis. Significantly, cells induced to enter apoptosis in the presence of the pan-caspase
inhibitor z-VAD, nevertheless form microtubule-like structures suggesting that microtubule formation is not dependent on caspase
activation. In contrast we found that treatment with EGTA-AM, an intracellular calcium chelator, prevents apoptotic microtubule
network formation, suggesting that intracellular calcium may play an essential role in the microtubule reformation. We propose
that apoptotic microtubule network is required to maintain plasma membrane integrity during the execution phase of apoptosis.
Electronic Supplementary Material Supplementary material is available in the online version of this article at . 相似文献
163.
Hausdorf B Helmkampf M Meyer A Witek A Herlyn H Bruchhaus I Hankeln T Struck TH Lieb B 《Molecular biology and evolution》2007,24(12):2723-2729
Phylogenetic analyses based on 79 ribosomal proteins of 38 metazoans, partly derived from 6 new expressed sequence tag projects for Ectoprocta, Entoprocta, Sipuncula, Annelida, and Acanthocephala, indicate the monophyly of Bryozoa comprising Ectoprocta and Entoprocta, 2 taxa that have been separated for more than a century based on seemingly profound morphological differences. Our results also show that bryozoans are more closely related to Neotrochozoa, including molluscs and annelids, than to Syndermata, the latter comprising Rotifera and Acanthocephala. Furthermore, we find evidence for the position of Sipuncula within Annelida. These findings suggest that classical developmental and morphological key characters such as cleavage pattern, coelomic cavities, gut architecture, and body segmentation are subject to greater evolutionary plasticity than traditionally assumed. 相似文献
164.
Krupa P Krsek P Javorník M Dostál O Srnec R Usvald D Proks P Kecová H Amler E Jancár J Gál P Plánka L Necas A 《Physiological research / Academia Scientiarum Bohemoslovaca》2007,56(Z1):S107-S114
Computed tomography (CT) is an effective diagnostic modality for three-dimensional imaging of bone structures, including the geometry of their defects. The aim of the study was to create and optimize 3D geometrical and real plastic models of the distal femoral component of the knee with joint surface defects. Input data included CT images of stifle joints in twenty miniature pigs with iatrogenic osteochondrosis-like lesions in medial femoral condyle of the left knee. The animals were examined eight and sixteen weeks after surgery. Philips MX 8000 MX and View workstation were used for scanning parallel plane cross section slices and Cartesian discrete volume creation. On the average, 100 slices were performed in each stifle joint. Slice matrices size was 512 x 512 with slice thickness of 1 mm. Pixel (voxel) size in the slice plane was 0.5 mm (with average accuracy of +/-0.5 mm and typical volume size 512 x 512 x 100 voxels). Three-dimensional processing of CT data and 3D geometrical modelling, using interactive computer graphic system MediTools formerly developed here, consisted of tissue segmentation (raster based method combination and 5 % of manual correction), vectorization by the marching-cubes method, smoothing and decimation. Stifle- joint CT images of three individuals of different body size (small, medium and large) were selected to make the real plastic models of their distal femurs from plaster composite using rapid prototyping technology of Zcorporation. Accuracy of the modeling was +/- 0.5 mm. The real plastic models of distal femurs can be used as a template for developing custom made press and fit scaffold implants seeded with mesenchymal stem cells that might be subsequently implanted into iatrogenic joint surface defects for articular cartilage-repair enhancement. 相似文献
165.
Nonmuscle myosin II (Myo2) has been shown to associate with membranes of the trans-Golgi network and to be involved in Golgi to ER retrograde protein transport. Here, we provide evidence that Myo2 not only associates with membranes but functions to transport vesicles on actin filaments (AFs). We used extracts from unactivated clam oocytes for these studies. AFs assembled spontaneously in these extracts and myosin-dependent vesicle transport was observed upon activation. In addition, actin bundles formed and moved relative to each other at an average speed of 0.30 microm/s. Motion analysis revealed that vesicles moved on the spontaneously assembled AFs at speeds greater than 1 microm/s. The motor on these vesicles was identified as a member of the nonmuscle Myo2 family based on sequence determination by Edman chemistry. Vesicles in these extracts were purified by sucrose gradient centrifugation and movement was reconstituted in vitro using skeletal muscle actin coated coverslips. When peripheral membrane proteins of vesicles including Myo2 were removed by salt stripping or when extracts were treated with an antibody specific to clam oocyte nonmuscle Myo2, vesicle movement was inhibited. Blebbistatin, a Myo2 specific inhibitor, also blocked vesicle movement. Myo2 light chain kinase activity was found to be essential for vesicle movement and sliding of actin bundles. Together, our data provide direct evidence that nonmuscle Myo2 is involved in actin-dependent vesicle transport in clam oocytes. 相似文献
166.
FourU: a novel type of RNA thermometer in Salmonella 总被引:2,自引:1,他引:1
167.
Friedrich D Hoffmann T Bär J Wermann M Manhart S Heiser U Demuth HU 《Biological chemistry》2007,388(2):155-162
Mutations in the mouse ATRN gene, which encodes attractin, offer links between this protein and pigmentation, metabolism, immune status and neurodegeneration. However, the mechanisms of attractin action are not understood. The protein was first identified in humans in a circulating form in serum. A protease activity was postulated similar to the membrane-bound ectoenzyme DP4/CD26. In the last decade, both DP4/CD26 and attractin were controversially described to be the major source of human serum DP4 activity. We purified attractin from human plasma, and found that the DP4-like activity of the preparation shows nearly identical kinetic properties to that of recombinant human DP4. In contrast, the native electrophoretic behavior of this activity is clearly different from human and porcine DP4, but co-migrates with the protein band identified as attractin by Western blotting and N-terminal sequencing. Nevertheless, a DP4 impurity could be demonstrated in purified plasma attractin and the activity could be removed by ADA affinity chromatography, resulting in a homogenous attractin preparation without DP4 activity. These results are substantiated by expression of different attractin isoforms, in which no DP4 activity was found either. This indicates that the multidomain protein attractin acts as a receptor or adhesion protein rather than a protease. 相似文献
168.
The complete nucleotide sequence of the cucumber (C. sativus L. var. Borszczagowski) chloroplast genome has been determined. The genome is composed of 155,293 bp containing a pair of
inverted repeats of 25,191 bp, which are separated by two single-copy regions, a small 18,222-bp one and a large 86,688-bp
one. The chloroplast genome of cucumber contains 130 known genes, including 89 protein-coding genes, 8 ribosomal RNA genes
(4 rRNA species), and 37 tRNA genes (30 tRNA species), with 18 of them located in the inverted repeat region. Of these genes,
16 contain one intron, and two genes and one ycf contain 2 introns. Twenty-one small inversions that form stem-loop structures, ranging from 18 to 49 bp, have been identified.
Eight of them show similarity to those of other species, while eight seem to be cucumber specific. Detailed comparisons of
ycf2 and ycf15, and the overall structure to other chloroplast genomes were performed. 相似文献
169.
170.
Sylvie Mazurier Annabelle Merieau Dorian Bergeau Victorien Decoin Daniel Sperandio Alexandre Crépin Corinne Barbey Katy Jeannot Ma?té Vicré-Gibouin Patrick Plésiat Philippe Lemanceau Xavier Latour 《Applied and environmental microbiology》2015,81(7):2579-2590
Pseudomonas fluorescens is commonly considered a saprophytic rhizobacterium devoid of pathogenic potential. Nevertheless, the recurrent isolation of strains from clinical human cases could indicate the emergence of novel strains originating from the rhizosphere reservoir, which could be particularly resistant to the immune system and clinical treatment. The importance of type three secretion systems (T3SSs) in the related Pseudomonas aeruginosa nosocomial species and the occurrence of this secretion system in plant-associated P. fluorescens raise the question of whether clinical isolates may also harbor T3SSs. In this study, isolates associated with clinical infections and identified in hospitals as belonging to P. fluorescens were compared with fluorescent pseudomonads harboring T3SSs isolated from plants. Bacterial isolates were tested for (i) their genetic relationships based on their 16S rRNA phylogeny, (ii) the presence of T3SS genes by PCR, and (iii) their infectious potential on animals and plants under environmental or physiological temperature conditions. Two groups of bacteria were delineated among the clinical isolates. The first group encompassed thermotolerant (41°C) isolates from patients suffering from blood infections; these isolates were finally found to not belong to P. fluorescens but were closely related and harbored highly conserved T3SS genes belonging to the Ysc-T3SS family, like the T3SSs from P. aeruginosa. The second group encompassed isolates from patients suffering from cystic fibrosis; these isolates belonged to P. fluorescens and harbored T3SS genes belonging to the Hrp1-T3SS family found commonly in plant-associated P. fluorescens. 相似文献