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61.
The two-faced nature of protozoa allowed us to study the relationship between cell cycle and behaviour in Euplotes crassus; the former represents one of the most typical cellular traits, the latter is one of the most significant characteristics of an organism. Dividing cells of E. crassus were isolated on a slide and recorded for 11 h: the classic ethographic parameters were calculated every 60 min. The percentage of mobile cells went from 0-100% in the first 2.5 h. This value was maintained for 6.5 h, but from 9 h the value began to drop, reaching 0% at 11 h. The relative frequency of leftward arcs was very high in the first hour, the radius and length of the arcs increased from 1-7 h; velocity showed a similar trend, peaking at 7 h. All our results showed that the behaviour of this ciliate is heavily affected by its cell-division cycle. 相似文献
62.
Carnevali S Petruzzelli S Longoni B Vanacore R Barale R Cipollini M Scatena F Paggiaro P Celi A Giuntini C 《American journal of physiology. Lung cellular and molecular physiology》2003,284(6):L955-L963
Cigarette smoke is a mixture of chemicals having direct and/or indirect toxic effects on different lung cells. We investigated the effect of cigarette smoke on human lung fibroblasts (HFL-1) oxidation and apoptosis. Cells were exposed to various concentrations (1, 5, and 10%) of cigarette smoke extract (CSE) for 3 h, and oxidative stress and apoptosis were assessed by fluorescence-activated cell sorting and confocal laser fluorescence microscopy. Both oxidative stress and apoptosis exhibited a dose-response relationship with CSE concentrations. Lung fibroblasts also showed marked DNA fragmentation at the Comet assay after exposure to 10% CSE. Coincubation of HLF-1 cells with N-acetylcysteine (1 mM) during CSE exposure significantly reduced oxidative stress, apoptosis, and DNA fragmentation, whereas preincubation (3 h) with the glutathione-depleting agent buthionine sulfoximine (125 microM) produced a significant increase of oxidative stress. Cigarette smoke is a potent source of oxidative stress, DNA damage, and apoptosis for HFL-1 cells, and we speculate that this could contribute to the development of pulmonary emphysema in the lungs of smokers. 相似文献
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Polverino de Laureto P Taddei N Frare E Capanni C Costantini S Zurdo J Chiti F Dobson CM Fontana A 《Journal of molecular biology》2003,334(1):129-141
The SH3 domains are small protein modules of 60-85 amino acid residues that are found in many proteins involved in intracellular signal transduction. The SH3 domain of the p85alpha subunit of bovine phosphatidylinositol 3'-kinase (PI3-SH3) under acidic solution adopts a compact denatured state from which amyloid fibrils are readily formed. This aggregation process has been found to be modulated substantially by solution conditions. Here, we have analyzed the conformational features of the native and acid denatured states of PI3-SH3 by limited proteolysis experiments using proteinase K and pepsin, respectively. Moreover, we have analyzed the propensity of PI3-SH3 to be hydrolyzed by pepsin at different stages in the process of aggregation and amyloid formation at pH 1.2 and 2.0 and compared the sites of proteolysis under these conditions with the conformational features of both native and aggregated PI3-SH3. The results demonstrate that the denatured state of PI3-SH3 formed at low pH is relatively resistant to proteolysis, indicating that it is partially folded. The long loop connecting beta-strands b and c in the native protein is the region in this structure most susceptible to proteolysis. Remarkably, aggregates of PI3-SH3 that are formed initially from this denatured state in acid solution display enhanced susceptibility to proteolysis of the long loop, suggesting that the protein becomes more unfolded in the early stages of aggregation. By contrast, the more defined amyloid fibrils that are formed over longer periods of time are completely resistant to proteolysis. We suggest that the protein aggregates formed initially are relatively dynamic species that are able readily to reorganize their interactions to enable formation of very well ordered fibrillar structures. In addition, the disordered and non-native character of the polypeptide chains in the early aggregates could be important in determining the high cytotoxicity that has been revealed in previous studies of these species. 相似文献
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Discovering lactic acid bacteria by genomics 总被引:25,自引:0,他引:25
Klaenhammer T Altermann E Arigoni F Bolotin A Breidt F Broadbent J Cano R Chaillou S Deutscher J Gasson M van de Guchte M Guzzo J Hartke A Hawkins T Hols P Hutkins R Kleerebezem M Kok J Kuipers O Lubbers M Maguin E McKay L Mills D Nauta A Overbeek R Pel H Pridmore D Saier M van Sinderen D Sorokin A Steele J O'Sullivan D de Vos W Weimer B Zagorec M Siezen R 《Antonie van Leeuwenhoek》2002,82(1-4):29-58
This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing of key statistics and interesting genomic features. These efforts will revolutionize our molecular view of Gram–positive bacteria, as up to 15 genomes from the low GC content lactic acid bacteria are expected to be available in the public domain by the end of 2003. Our collective view of the lactic acid bacteria will be fundamentally changed as we rediscover the relationships and capabilities of these organisms through genomics. 相似文献
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Franciotta D Martino G Zardini E Furlan R Bergamaschi R Gironi M Bergami A Angelini G De Benedetti F Pignatti P Moscato G Cosi V 《European cytokine network》2002,13(1):99-103
In multiple sclerosis (MS), pathological white matter damage in the central nervous system is sustained by immune-inflammatory response. Caspase-1 plays a pivotal role in immune-mediated inflammation, as it regulates the cellular export of IL-1beta and IL-18. We carried out a preliminary in vitro study of the kinetics of extracellular caspase-1 release. We then measured caspase-1 levels in paired serum and cerebrospinal fluid (CSF) samples of 75 MS patients, 15 healthy subjects, and patients with other neurological diseases. Paired synovial fluid and serum samples of patients with juvenile idiopathic arthritis, and paired sputum and serum samples of asthma patients were also studied. Mean serum caspase-1 concentrations did not differ between groups. Caspase-1 was detected in the CSF of patients with acute, but not stable, MS [7.5 +/- (SEM) 0.9 pg/ml; test's sensitivity, 56% and specificity, 100%]. Its levels correlated with pleocytosis. The highest mean caspase-1 levels were found in the arthritic synovial fluids (945.5 +/- 126.6 pg/ml, which correlated with erythrocyte sedimentation rate), and in the sputum samples (370.1 +/- 71.0 pg/ml, which correlated with the number of macrophages in the sputum). On condition that caspase-1 is determined in the fluids pertaining to the disease-specific inflammatory sites, its level is a reliable marker of ongoing immune-inflammatory response. The enzyme measurement in CSF can also help define state-trait in MS. 相似文献
69.
Amicosante M Gioia C Montesano C Casetti R Topino S D'Offizi G Cappelli G Ippolito G Colizzi V Poccia F Pucillo LP 《Molecular medicine (Cambridge, Mass.)》2002,8(12):798-807
BACKGROUND: Human immunodeficiency virus (HIV)- specific CD8-positive cytotoxic T-lymphocytes (CTL) play a key role in controlling HIV infection. Monitoring CTL response could be clinically relevant during structured therapy interruption (STI), HIV exposure, and vaccine trials. However, HLA patients' restriction and HIV variability limited the development of a CTL assay with broad specificity. MATERIALS AND METHODS: We designed an HLA-class I/HIV-1 clade independent assay for assessing HIV- specific CTL by using a computer-assisted selection ofthe CTL epitopes. Twenty-eight 15-mers were selected by peptide-binding motifs analysis using different databases (HIV-Immunology Database, SYFPEITHI, BIMAS). Altogether they putatively bind to more than 90% of HLA haplotypes in different populations, with an overall HIV-1 variability below 9%. The peptide pool was used as an antigen in an intracellular cytokine staining (ICS) assay for quantifying HIV-specific CTL response. RESULTS: The test can be performed using both fresh and cryopreserved peripheral blood mononuclear cells (PBMC), whereas GAG protein as antigen works only on fresh PBMC. A significantly higher CTL response with respect to HIV-negative controls was detected in all HIV-1 infected subjects of two groups of patients with different ethnicities (Caucasians and Africans) and coming from areas with different HIV-1 clade prevalences (clade B and A/G, respectively). In Caucasian patients, after month of STI, the number of HIV-1 specific CTL (2,896 +/- 2,780 IFN-gamma specific CD8 cells/ml) was significantly higher than that found at enrolment (2,125 +/- 4,426 IFN-gamma specific CD8 cells/ml, p< 0.05). CONCLUSIONS: These data indicate that this CTL assay is broadly specific and could represent a useful clinical tool for HIV immunodiagnostic independent of HLA-haplotype and HIV-clade variabilities. 相似文献
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