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141.
Słowik-Zyłka D Safranow K Dziedziejko V Bukowska H Ciechanowski K Chlubek D 《Journal of biochemical and biophysical methods》2004,61(3):313-329
Pentosidine is an advanced glycation end-product (AGE) appearing when arginine and lysine residues in proteins are cross-linked with carbonyl derivatives. This paper presents an improved method for the synthesis of pentosidine and reversed-phase chromatography of this substance with fluorometric detection that enables sensitive (0.01 pmol/mg protein) and specific determination of pentosidine in plasma. Separation is done twice on the same C(18) Vydac 218TP54 column, first with trifluoroacetic acid and next with heptafluorobutyric acid as ion pair. The inter-day coefficient of variation is 6.4% at pentosidine concentration in plasma of 25 pmol/mg protein and 8% at 1.7 pmol/mg protein. Spectral properties of pentosidine exploited during identification of the substance with UV absorption and fluorescence detectors are described. Maximum of absorbance was observed at 325 nm, maximum fluorescence at lambda(ex)/lambda(em)=330/373 nm. The method may prove useful for the study of processes associated with generation and accumulation of pentosidine in the body as a marker of AGE production in healthy subjects and patients with chronic renal failure. 相似文献
142.
The mitochondrial genomes of some Phaseolus species contain a fragment of chloroplast trnA gene intron, named pvs-trnA for its location within the Phaseolus vulgaris sterility sequence (pvs). The purpose of this study was to determine the type of transfer (intracellular or horizontal) that gave rise to pvs-trnA. Using a PCR approach we could not find the respective portion of the trnA gene as a part of pvs outside the Phaseolus genus. However, a BLAST search revealed longer fragments of trnA present in the mitochondrial genomes of some Citrus species, Helianthus annuus and Zea mays. Basing on the identity or near-identity between these mitochondrial sequences and their chloroplast counterparts we concluded that they had relocated from chloroplasts to mitochondria via recent, independent, intracellular DNA transfers. In contrast, pvs-trnA displayed a relatively higher sequence divergence when compared with its chloroplast counterpart from Phaseolus vulgaris. Alignment of pvs-trnA with corresponding trnAfragments from 35 plant species as well as phylogenetic analysis revealed that pvs-trnA grouped with non-eudicot sequences and was well separated from all Fabalessequences. In conclusion, we propose that pvs-trnA arose via horizontal transfer of a trnA intron fragment from chloroplast of a non-eudicot plant to Phaseolus mitochondria. This is the first example of horizontal transfer of a chloroplast sequence to the mitochondrial genome in higher plants. 相似文献
143.
Bläker M Arrenberg P Stange I Schulz M Burghardt S Michaelis H Pace A Greten H von Schrenck T de Weerth A 《Regulatory peptides》2004,118(1-2):111-117
144.
Trefoil factor family (TFF) domain peptides, products of mucin-secreting epithelial cells, are thought to influence mucosal integrity. Molecular studies revealed that mammalian TFFs lack transmembrane domains. Using immunocytochemistry and FACS analysis we demonstrated the association of TFF1 with the cell membrane in MCF-7 (a breast adenocarcinoma cell line), and tested the hypothesis that glycosylphosphatidylinositol (GPI) linkage is the mechanism for this association. Cleavage of GPI anchorage using phospholipase C did not affect TFF1 binding to the cell membrane. Our results demonstrate for the first time that TFF1 is associated with the cell membrane of MCF-7 cells and is not linked via a GPI anchor. 相似文献
145.
Somatic incompatibility is not an absolute block to nuclear exchange between incompatible mycelia of the basidiomycete Heterobasidion annosum in vitro. Under laboratory conditions new heterokaryotic genotypes can be isolated from the gap between incompatible heterokaryons, and nuclear migration between pairs of heterokaryons grown in Petri dishes has been observed. In this study, we test the hypothesis of nuclear transfer and reassortment between heterokaryotic mycelia in natural populations of H. annosum. We developed six microsatellite markers to genotype nuclei populating 21 somatically incompatible mycelia of H. annosum isolated from a single stump of Picea abies, and found that the detected heterokaryons share nuclei; 10 of the nuclear haplotypes were found in more than one mycelium. In one isolate, four nuclear types were found in the same mycelium. These findings indicate that new heterokaryons can be formed as a result of nuclear reassortment between incompatible heterokaryotic mycelia in nature. 相似文献
146.
Chromosome stability depends on accurate chromosome segregation and efficient DNA double-strand break (DSB) repair. Sister chromatid cohesion, established during S phase by the protein complex cohesin, is central to both processes. In the absence of cohesion, chromosomes missegregate and G2-phase DSB repair fails. Here, we demonstrate that G2-phase repair also requires the presence of cohesin at the damage site. Cohesin components are shown to be recruited to extended chromosome regions surrounding DNA breaks induced during G2. We find that in the absence of functional cohesin-loading proteins (Scc2/Scc4), the accumulation of cohesin at DSBs is abolished and repair is defective, even though sister chromatids are connected by S phase generated cohesion. Evidence is also provided that DSB induction elicits establishment of sister chromatid cohesion in G2, implicating that damage-recruited cohesin facilitates DNA repair by tethering chromatids. 相似文献
147.
Apparent X-linked primary ciliary dyskinesia associated with retinitis pigmentosa and a hearing loss
Three brothers, one 10-year-old and a pair of 14-year-old dizygotic twins--expressed the classical, early-onset retinitis pigmentosa (RP) with typical ophthalmoscopic findings, night blindness, visual field constricted to 10 degrees and flat ERG response. All three brothers were also diagnosed with primary ciliary dyskinesia (PCD) and had recurrent respiratory infections, chronic sinusitis and bronchiectasis. In all of them, resection of the middle lobe of the right lung was performed. A similar clinical picture of coexisting RP and PCD was noted in the brother of the probands' mother. All probands displayed situs solitus. Consistent with the X-linked mode of RP inheritance, there were also three obligatory female carriers of the disorder in this family: the mother of the affected boys, her mother and a daughter of her brother. In all of them, retinitis pigmentosa "sine pigmento" was found with milder but clinically significant symptoms (mild night blindness, visual field constricted to 30 degrees, and scotopic and photopic ERG responses reduced to 30-60%). No extraocular symptoms were detected in any of the heterozygous female carriers. This family presents an example of two rare phenomena: X-linked dominant retinitis pigmentosa (with milder expression in females) and a rare combination of RP with recurrent respiratory infections due to PCD. 相似文献
148.
The role of ephrins and Eph receptors in cancer 总被引:10,自引:0,他引:10
Eph receptors are the largest receptor tyrosine kinase family of transmembrane proteins with an extracellular domain capable of recognizing signals from the cells’ environment and influencing cell–cell interaction and cell migration. Ephrins are the ligands to Eph receptors and stimulate bi-directional signaling of the Eph/ephrin axis. Eph receptor and ephrin overexpression can result in tumorigenesis as related to tumor growth and survival and is associated with angiogenesis and metastasis in many types of human cancer. Recent data suggest that Eph/ephrin signaling could play an important role in the development of novel inhibition strategies and cancer treatments to potentially target this receptor tyrosine kinase and/or its ligand. A deeper understanding of the molecular basis for normal versus defective cell–cell interaction through the Eph/ephrin axis will enable the potential development of novel cancer treatments. This review emphasizes the biology of Eph/ephrin as well as the potential for novel targeted therapy through this pathway. 相似文献
149.
Characteristics and a comparison of three classes of microsatellite-based markers and their application in plants 总被引:4,自引:0,他引:4
Microsatellites (SSR--simple sequence repeats, STR--short tandem repeats, SSLP--simple sequence length polymorphism, VNTR--variable number of tandem repeats) are the class of repetitive DNA sequences present in all living organisms. Particular characteristics of microsatellites, such as their presence in the genomes of all living organisms, high level of allelic variation, co-dominant mode of inheritance and potential for automated analysis make them an excellent tool for a number of approaches like genotyping, mapping and positional cloning of genes. The three most popular types of markers containing microsatellite sequences that are presently used are: (1) SSR (simple sequence repeats), generated by amplifying in a PCR reaction with the use of primers complementary to flanking regions; (2) ISSR (inter-simple sequence repeats), based on the amplification of regions between inversely oriented closely spaced microsatellites; and (3) SAMPL (selective amplification of microsatellite polymorphic loci), which utilises AFLP (amplified fragment-length polymorphism) methodology, with one exception--for the second amplification, one of the starters is complementary to the microsatellite sequence. The usefulness of the three above-mentioned markers for numerous purposes has been well documented for plants. 相似文献
150.
Huiskonen JT Kivelä HM Bamford DH Butcher SJ 《Nature structural & molecular biology》2004,11(9):850-856
Biological membranes are notoriously resistant to structural analysis. Excellent candidates to tackle this problem in situ are membrane-containing viruses where the membrane is constrained by an icosahedral capsid. Cryo-EM and image reconstruction of bacteriophage PM2 revealed a membrane bilayer following the internal surface of the capsid. The viral genome closely interacts with the inner leaflet. The capsid, at a resolution of 8.4 A, reveals 200 trimeric capsomers with a pseudo T = 21 dextro organization. Pentameric receptor-binding spikes protrude from the surface. It is evident from the structure that the PM2 membrane has at least two important roles in the life cycle. First, it acts as a scaffold to nucleate capsid assembly. Second, after host recognition, it fuses with the host outer membrane to promote genome entry. The structure also sheds light on how the viral supercoiled circular double-stranded DNA genome might be packaged and released. 相似文献