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1.
Lucia Di Giambattista P. Grimaldi S. Gaudenzi D. Pozzi M. Grandi S. Morrone I. Silvestri A. Congiu Castellano 《European biophysics journal : EBJ》2010,39(6):929-934
We have made a preliminary analysis of the results about the effects on tumoral cell line (lymphoid T cell line Jurkat) induced
by UVB radiation (dose of 310 mJ/cm2) with and without a vegetable mixture. In the present study, we have used two techniques: Fourier transform infrared spectroscopy
(FTIR) and flow cytometry. FTIR spectroscopy has the potential to provide the identification of the vibrational modes of some
of the major compounds (lipid, proteins and nucleic acids) without being invasive in the biomaterials. The second technique
has allowed us to perform measurements of cytotoxicity and to assess the percentage of apoptosis. We already studied the induction
of apoptotic process in the same cell line by UVB radiation; in particular, we looked for correspondences and correlations
between FTIR spetroscopy and flow cytometry data finding three highly probable spectroscopic markers of apoptosis (Pozzi et
al. in Radiat Res 168:698–705, 2007). In the present work, the results have shown significant changes in the absorbance and
spectral pattern in the wavenumber protein and nucleic acids regions after the treatments. 相似文献
2.
Carmen de Sena-Tomás Mónica Navarro-González Ursula Kües José Pérez-Martín 《Genetics》2013,195(1):47-57
The fungal fruiting body or mushroom is a multicellular structure essential for sexual reproduction. It is composed of dikaryotic cells that contain one haploid nucleus from each mating partner sharing the same cytoplasm without undergoing nuclear fusion. In the mushroom, the pileus bears the hymenium, a layer of cells that includes the specialized basidia in which nuclear fusion, meiosis, and sporulation occur. Coprinopsis cinerea is a well-known model fungus used to study developmental processes associated with the formation of the fruiting body. Here we describe that knocking down the expression of Atr1 and Chk1, two kinases shown to be involved in the response to DNA damage in a number of eukaryotic organisms, dramatically impairs the ability to develop fruiting bodies in C. cinerea, as well as other developmental decisions such as sclerotia formation. These developmental defects correlated with the impairment in silenced strains to sustain an appropriated dikaryotic cell cycle. Dikaryotic cells in which chk1 or atr1 genes were silenced displayed a higher level of asynchronous mitosis and as a consequence aberrant cells carrying an unbalanced dose of nuclei. Since fruiting body initiation is dependent on the balanced mating-type regulator doses present in the dikaryon, we believe that the observed developmental defects were a consequence of the impaired cell cycle in the dikaryon. Our results suggest a connection between the DNA damage response cascade, cell cycle regulation, and developmental processes in this fungus. 相似文献
3.
Sharat J. Vayttaden Jacqueline Friedman Tuan M. Tran Thomas C. Rich Carmen W. Dessauer Richard B. Clark 《PLoS computational biology》2010,6(1)
We developed a unified model of the GRK-mediated β2 adrenergic receptor (β2AR) regulation that simultaneously accounts for six different biochemical measurements of the system obtained over a wide range of agonist concentrations. Using a single deterministic model we accounted for (1) GRK phosphorylation in response to various full and partial agonists; (2) dephosphorylation of the GRK site on the β2AR; (3) β2AR internalization; (4) recycling of the β2AR post isoproterenol treatment; (5) β2AR desensitization; and (6) β2AR resensitization. Simulations of our model show that plasma membrane dephosphorylation and recycling of the phosphorylated receptor are necessary to adequately account for the measured dephosphorylation kinetics. We further used the model to predict the consequences of (1) modifying rates such as GRK phosphorylation of the receptor, arrestin binding and dissociation from the receptor, and receptor dephosphorylation that should reflect effects of knockdowns and overexpressions of these components; and (2) varying concentration and frequency of agonist stimulation “seen” by the β2AR to better mimic hormonal, neurophysiological and pharmacological stimulations of the β2AR. Exploring the consequences of rapid pulsatile agonist stimulation, we found that although resensitization was rapid, the β2AR system retained the memory of the previous stimuli and desensitized faster and much more strongly in response to subsequent stimuli. The latent memory that we predict is due to slower membrane dephosphorylation, which allows for progressive accumulation of phosphorylated receptor on the surface. This primes the receptor for faster arrestin binding on subsequent agonist activation leading to a greater extent of desensitization. In summary, the model is unique in accounting for the behavior of the β2AR system across multiple types of biochemical measurements using a single set of experimentally constrained parameters. It also provides insight into how the signaling machinery can retain memory of prior stimulation long after near complete resensitization has been achieved. 相似文献
4.
Legionella pneumophila in Cooling Towers: Fluctuations in Counts, Determination of Genetic Variability by Pulsed-Field Gel Electrophoresis (PFGE), and Persistence of PFGE Patterns 下载免费PDF全文
Sonia Ragull Marian Garcia-Nuez Maria Luisa Pedro-Botet Nieves Sopena Maria Esteve Rafael Montenegro Miquel Sabri 《Applied microbiology》2007,73(16):5382-5384
The concentrations of Legionella pneumophila in cooling towers may vary considerably over short periods of time, producing significant fluctuations throughout the year. Despite genetic variability, in small geographical areas the same indistinguishable pulsed-field gel electrophoresis patterns may be shared among different cooling towers and persist over time. 相似文献
5.
Tetyana Denysenko Luisa Gennero Carola Juenemann Isabella Morra Paolo Masperi Vincenzo Ceroni Antonella Pragliola Antonio Ponzetto Antonio Melcarne 《Cell biochemistry and function》2014,32(2):164-176
Glioblastomas (GBMs) are the most lethal primary brain tumours. Increasing evidence shows that brain tumours contain the population of stem cells, so‐called cancer stem cells (CSCs). Stem cell marker CD133 was reported to identify CSC population in GBM. Further studies have indicated that CD133 negative cells exhibiting similar properties and are able to initiate the tumour, self‐renew and undergo multilineage differentiation. GBM is a highly heterogeneous tumour and may contain different stem cell populations with different functional properties. We characterized five GBM cell lines, established from surgical samples, according to the marker expression, proliferation and differentiation potential. CD133 positive cell lines showed increased proliferation rate in neurosphere condition and marked differentiation potential towards neuronal lineages. Whereas two cell lines low‐expressing CD133 marker showed mesenchymal properties in vitro, that is high proliferation rate in serum condition and differentiation in mesenchymal cell types. Further, we compared therapy resistance capacity of GBM cell lines treated with hydroxyurea. Our results suggest that CSC concept is more complex than it was believed before, and CD133 could not define entire stem cell population within GBM. At least two different subtypes of GBM CSCs exist, which may have different biological characteristics and imply different therapeutic strategies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
7.
Eduardo León-Ruiz Purificación Alcázar Eugenio Domínguez-Vilches Carmen Galán 《Aerobiologia》2011,27(1):37-50
The present study sought to determine which of the common Poaceae species in the study area contribute most to the Poaceae
pollen season curve, and to determine the phenological behaviour of the species studied. The different floral phenophases
in thirty-three Poaceae species common in and around the city of Córdoba (SW Iberian Peninsula) were checked periodically
over the period 2004–2006. Results showed that longer phenological ranges were recorded in the coolest and wettest year, and
shorter ranges in the warmest and driest year. Moreover, ranges varied as a function of altitude: populations in lower-lying
areas flowered earlier than those at higher altitudes. The results, taken in conjunction with the findings of preliminary
research into potential pollen production, showed that probably only four of the Poaceae species studied—Dactylis glomerata, Lolium rigidum, Trisetaria panicea and Vulpia geniculata—were major contributors to the Poaceae airborne pollen curve. 相似文献
8.
Luisa Lanfranco 《Theoretical biology forum》2003,96(1):31-54
Plant transformation has had a deep impact on several aspects of basic and applied research. Genetic transformation has offered new opportunities compared to traditional breeding practises since it allows the integration into a host genome of specific sequences leading to a strong reduction of the casualness of gene transfer. One of the first target areas was plant protection against pests, pathogens and environmental stresses while the recent plant engineering programs are aimed at increasing food quality, in particular at increasing nutritional characteristics of food crops. Moreover, transgenic plants, tissue or cell cultures represent an attractive biological system for producing heterologous proteins since they offer economic and qualitative benefits. High yield production can be obtained and large-scale commercial production will take advantage of the existing infrastructure for crop cultivation, processing and storage. There are also qualitative benefits since protein synthesis secretion and post-translational modifications are similar in plants and animal cells. There are no human viral pathogens harboured by plants: thus, especially for pharmaceuticals, plants represent the safer production system. Plant transformation has become an essential instrument also for basic research, in particular for the functional characterisation of genes identified by sequencing of whole genomes. Large collections of insertion mutants have been obtained in the model plant Arabidopsis to provide a high level of genome saturation that means 95% chance of inactivating any gene at least once. To instil greater public confidence in modern plant biotechnology recent advances have already been made to overcome the potential risks for human health and environment. 相似文献
9.
The membrane ionic conductances of dispersed parathyroid cells kept in primary culture were studied using the "whole-cell" and "inside-out excised patch" variants of the patch-clamp technique. The major component of the total current was a voltage-dependent outward K+ current without an appreciable inward current. The amplitude of the K+ current was markedly reduced when free internal Ca2+ was buffered by addition of 10 mM EGTA. Recordings of single-channel current in excised membrane patches revealed the presence of K+ channels with large unitary conductance (200 pS in symmetrical 130 mM K+ solutions) which were also activated by depolarization when internal Ca2+ concentration was about 10(-5)-10(-6) M. At any membrane voltage these channels were closed most of the time at internal Ca2+ concentrations lower than 10(-10) M. These results demonstrate the existence of a Ca2+- and voltage-dependent K+ permeability in parathyroid cells which may participate in the unusual membrane potential changes induced by alterations of external Ca2+ and, possibly, in the regulation of parathormone secretion. 相似文献
10.
A rapid extraction method for screening aflatoxin producing potential ofAspergillus flavus group isolates is described. The method is performed using a moist wheat medium with ca. five infected grains extracted with 2 mL of chloroform, and using thin layer chromatography. This method was proved with 95A. flavus isolates from animal feeds. 相似文献