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101.
Houtman R Krijgsveld J Kool M Romijn EP Redegeld FA Nijkamp FP Heck AJ Humphery-Smith I 《Proteomics》2003,3(10):2008-2018
A mouse model for nonatopic asthma was employed to study the alterations of the lung proteome to gain insight into the underlying molecular mechanisms of disease pathophysiology post-challenge. Lung samples from asthmatic and control mice were used to generate 24 high quality two-dimensional electrophoresis gels wherein 2115 proteins were examined for disease relevance. In total, 23 proteins were significantly up- or down-regulated following hapten-challenge of dinitro-fluorobenzene-hypersensitive mice. Twenty proteins were identified by mass spectrometry, of which 18 could be linked to asthma related symptoms, such as stress and inflammation, lung detoxification, plasma exudation and/or tissue remodeling. As such, proteomics was clearly vindicated as a means of studying this complex disease phenomenon. The proteins found in this study may not necessarily play a role in the immunological mechanisms and/or pathophysiology of asthma development. However, they may prove useful as surrogate biomarkers for quantitatively monitoring disease state progression or response to therapy. The mathematics of achieving statistical confidence from low numbers of gel replicates containing large numbers of independent variables stress the need for high numbers of replicates to better sample the population of proteins revealed by two-dimensional gel electrophoresis. 相似文献
102.
103.
Uniform cAMP stimulation of Dictyostelium cells induces localized patches of signal transduction and pseudopodia
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Postma M Roelofs J Goedhart J Gadella TW Visser AJ Van Haastert PJ 《Molecular biology of the cell》2003,14(12):5019-5027
The chemoattractant cAMP induces the translocation of cytosolic PHCrac-GFP to the plasma membrane. PHCrac-GFP is a green fluorescent protein fused to a PH domain that presumably binds to phosphatydylinositol polyphosphates in the membrane. We determined the relative concentration of PHCrac-GFP in the cytosol and at different places along the cell boundary. In cells stimulated homogeneously with 1microM cAMP we observed two distinct phases of PHCrac-GFP translocation. The first translocation is transient and occurs to nearly the entire boundary of the cell; the response is maximal at 6-8 s after stimulation and disappears after approximately 20 s. A second translocation of PHCrac-GFP starts after approximately 30 s and persists as long as cAMP remains present. Translocation during this second response occurs to small patches with radius of approximately 4-5 microm, each covering approximately 10% of the cell surface. Membrane patches of PHCrac-GFP are both temporally and spatially closely associated with pseudopodia, which are extended at approximately 10 s from the area with a PHCrac-GFP patch. These signaling patches in pseudopodia of homogeneously stimulated cells resemble the single patch of PHCrac-GFP at the leading edge of a cell in a gradient of cAMP, suggesting that PHCrac-GFP is a spatial cue for pseudopod formation also in uniform cAMP. 相似文献
104.
105.
Hajizadeh S DeGroot J TeKoppele JM Tarkowski A Collins LV 《Arthritis research & therapy》2003,5(5):R234-R240
We investigated whether plasma and synovial fluid (SF) samples from patients with rheumatoid arthritis (RA) contained extracellular
mitochondrial DNA (mtDNA) or the oxidatively damaged DNA adduct 8-hydroxy-2'-deoxyguanosine (8-oxodG). Moreover, we correlated
the laboratory findings of the patients with RA with their levels of mtDNA and 8-oxodG. SF and plasma samples from 54 patients
with RA, SF from 30 non-arthritic control subjects, and plasma from 22 healthy volunteers were collected. The samples were
subjected to polymerase chain reaction (PCR) using mitochondrial genomic primers, and the products were analyzed by SDS–polyacrylamide-gel
electrophoresis. The intensities of the PCR-amplified bands were quantified and normalized to a reference sample. Furthermore,
the SF samples were assayed by enzyme-linked immunosorbent assay for 8-oxodG. Extracellular PCR-amplifiable mtDNA was detected
in the SF of 38 of 54 (70%) patients with RA, but not in any of the SF controls. PCR-amplifiable mtDNA was detected in the
plasma of 30 of 54 (56%) of patients with RA and in 6 of 22 (27%) of the healthy volunteers. The levels of mtDNA in the plasma
and SF samples of patients with RA were significantly higher (P < 0.0001) than in the respective control samples. The presence of both mtDNA and 8-oxodG in SF was significantly correlated
with the presence of rheumatoid factor in the patients with RA. Extracellular mtDNA and oxidized DNA were detected in the
SF of the great majority of patients with RA, but were absent or present at low levels in the control SF. These findings indicate
that endogenous nucleic acid compounds might participate in joint inflammation by activating immune cells in the joints to
produce proinflammatory cytokines. 相似文献
106.
When we reach out for an object with our hand, we transform visual information about the object's position into muscle contractions that will bring our digits to that position. If we reach out with a tool the transformation is different, because the muscle contractions must bring the critical part of the tool to the object, rather than the digits. The difference between the motion of the hand and that of the tool can be quite large, as when moving a computer mouse across a table to bring a cursor to a position on a screen. We examined the responses to unpredictable visual perturbations during such movements. People responded about as quickly to changes in the position of the target when pointing with the mouse as when doing so with their hand. They also responded about as quickly when the cursor was displaced as when the target was displaced. We show that this is not because the visually perceived separation between target and cursor is transformed into a desired displacement of the hand. Our conclusion is that our actions are controlled by the judged positions of the end-effector and the target, even when the former is quite detached from the muscles and joints that are involved in the action. 相似文献
107.
Saeij JP Groeneveld A Van Rooijen N Haenen OL Wiegertjes GF 《Diseases of aquatic organisms》2003,57(1-2):67-75
Carp Cyprinus carpio macrophages were depleted by intraperitoneal (i.p.) injection of clodronate-liposomes for the in vivo study of the effect of macrophage depletion on the resistance of carp to infection with blood flagellate parasites. Clodronate released inside the cell induces apoptosis of (murine) macrophages. Following i.p. injection of carp with liposomes alone, but not with Trypanoplasma borreli, neutrophilic granulocytes rapidly migrated from the head kidney to the peritoneal cavity. The majority of liposomes in the peritoneal cavity were not taken up by newly arrived neutrophilic granulocytes, however, but by resident macrophages. After 2 i.p. injections of clodronate-liposomes, the percentage of macrophages present in the peritoneal cavity was significantly reduced, as evaluated by flow cytometry. Macrophage-depleted carp that were infected i.p. with T. borreli suffered from high mortality. However, these fish did not show lethal parasitaemia but did show clear bacteraemia. Macrophage-depleted carp that were infected i.p. with Trypanosoma carassii showed a minor increase in parasitaemia. In addition, macrophage-depleted carp, immune to T. borreli as a result of having survived a prior infection, remained immune to i.p. reinfection with T. borreli. Succesful depletion of peritoneal macrophages seemed to have a minor effect on the resistance of carp against blood flagellates. However, carp macrophages are essential as a first line of defence against (bacterial) infection. 相似文献
108.
Pouwels J Moracci M Cobucci-Ponzano B Perugino G van der Oost J Kaper T Lebbink JH de Vos WM Ciaramella M Rossi M 《Extremophiles : life under extreme conditions》2000,4(3):157-164
Sβgly and CelB are well-studied hyperthermophilic glycosyl hydrolases, isolated from the Archaea Sulfolobus solfataricus and Pyrococcus furiosus, respectively. Previous studies revealed that the two enzymes are phylogenetically related; they are very active and stable
at high temperatures, and their overall three-dimensional structure is very well conserved. To acquire insight in the molecular
determinants of thermostability and thermoactivity of these enzymes, we have performed a detailed comparison, under identical
conditions, of enzymological and biochemical parameters of Sβgly and CelB, and we have probed the basis of their stability
by perturbations induced by temperature, pH, ionic strength, and detergents. The major result of the present study is that,
although the two enzymes are remarkably similar with respect to kinetic parameters, substrate specificity, and reaction mechanism,
they are strikingly different in stability to the different physical or chemical perturbations induced. These results provide
useful information for the design of further experiments aimed at understanding the structure–function relationships in these
enzymes.
Received: May 20, 1999 / Accepted: January 10, 2000 相似文献
109.
Physiological Activity of Campylobacter jejuni Far below the Minimal Growth Temperature 总被引:3,自引:0,他引:3
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Wilma C. Hazeleger Jeroen A. Wouters Frank M. Rombouts Tjakko Abee 《Applied microbiology》1998,64(10):3917-3922
The behavior of Campylobacter jejuni at environmental temperatures was examined by determining the physiological activities of this human pathogen. The minimal growth temperatures were found to be 32 and 31°C for strains 104 and ATCC 33560, respectively. Both strains exhibited a sudden decrease in growth rate from the maximum to zero within a few degrees not only near the maximal growth temperature but also near the minimal growth temperature. This could be an indication that a temperature-dependent transition in the structure of a key enzyme(s) or regulatory compound(s) determines the minimal growth temperature. Oxygen consumption, catalase activity, ATP generation, and protein synthesis were observed at temperatures as low as 4°C, indicating that vital cellular processes were still functioning. PCR analysis showed that cold shock protein genes, which play a role in low-temperature adaptation in many bacteria, are not present in C. jejuni. The fact that chemotaxis and aerotaxis could be observed at all temperatures shows that the pathogen is able to move to favorable places at environmental temperatures, which may have significant implications for the survival of C. jejuni in the environment. 相似文献
110.
Salmonella typhimurium Encodes an SdiA Homolog, a Putative Quorum Sensor of the LuxR Family, That Regulates Genes on the Virulence Plasmid 总被引:6,自引:0,他引:6
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