Иммунорегуляторные и цитотоксические свойства бронхоальвеолярного смыва при обострении бронхиальной астмы

Cytotoxic activity of cell free fraction (CFF) of the broncho-alveolar lavage (BAL) according to its ability to lyse the cells from the monocytoid human blast cell line J96 was assessed 8 asthmatics and 4 normals. Immunoregulatory properties of CFF were assessed according to its influence on spontaneous and konkanavaline A induced proliferation of peripheric human blood lymphocytes, cultivated in the presence of 3H-timidine. As a rule during «normal» stage CFF has no cytotoxic and mitogenic activity, and very slightly inhibits mitogenic response of lymphocytes stimulated by konkavaline in vitro. During the state of bronchial asthma CF of BAL presents high cytotoxic activity, which is not followed by appearance or rise in level of tumor necrotizing factor a. Immunoregulatory properties of BAL CFF are changing during asthma exacerbations: There appear some factors capable of inhibiting the spontaneous proliferation of peripheric human blood lymphocytes and strengthen their response to mitogens in comparison with the «normal» BAL CFF.У 8 больных бронхиальной астмой и 4 лиц без легочной патологии определяли цитотоксическую активность бесклеточной фракции (БФ) бронхоальвеолярных смывов (БАС) по её способности лизировать клетки моноцитоидной линии опухолевых клеток человека J 96. Иммунорегуляторные свойства БФ оценивали по её влиянию на спонтанную и индуцированную конканавалином А пролиферацию лимфоцитов периферической крови человека, культивируемых в присутствии 3Н-тимидина. В «норме» БФ смыва, как правило, не обладает цитотоксической и митогенной активностью, а также незначительно ингибирует индуцируемый конканавалином митогенной ответ лимфоцитов in vitro. При бронхиальной астме БФ БАС обладает высокой цитотоксической активностью, которая не сопровождается появлением или повышением концентрации фактора некроза опухоли а. Иммунорегуляторные свойства БФ БАС во время обострения бронхиальной астмы изменяются: в ней появляются факторы, способные подавлять спонтанную пролиферацию лимфоцитов периферической крови человека и усиливать их ответ на митогены по сравнению с БФ БАС в «норме»

Macro-to-Micro Structural Proteomics: Native Source Proteins for High-Throughput Crystallization

Structural biology and structural genomics projects routinely rely on recombinantly expressed proteins, but many proteins and complexes are difficult to obtain by this approach. We investigated native source proteins for high-throughput protein crystallography applications. The Escherichia coli proteome was fractionated, purified, crystallized, and structurally characterized. Macro-scale fermentation and fractionation were used to subdivide the soluble proteome into 408 unique fractions of which 295 fractions yielded crystals in microfluidic crystallization chips. Of the 295 crystals, 152 were selected for optimization, diffraction screening, and data collection. Twenty-three structures were determined, four of which were novel. This study demonstrates the utility of native source proteins for high-throughput crystallography

Beta-Strand Interfaces of Non-Dimeric Protein Oligomers Are Characterized by Scattered Charged Residue Patterns

Protein oligomers are formed either permanently, transiently or even by default. The protein chains are associated through intermolecular interactions constituting the protein interface. The protein interfaces of 40 soluble protein oligomers of stœchiometries above two are investigated using a quantitative and qualitative methodology, which analyzes the x-ray structures of the protein oligomers and considers their interfaces as interaction networks. The protein oligomers of the dataset share the same geometry of interface, made by the association of two individual β-strands (β-interfaces), but are otherwise unrelated. The results show that the β-interfaces are made of two interdigitated interaction networks. One of them involves interactions between main chain atoms (backbone network) while the other involves interactions between side chain and backbone atoms or between only side chain atoms (side chain network). Each one has its own characteristics which can be associated to a distinct role. The secondary structure of the β-interfaces is implemented through the backbone networks which are enriched with the hydrophobic amino acids favored in intramolecular β-sheets (MCWIV). The intermolecular specificity is provided by the side chain networks via positioning different types of charged residues at the extremities (arginine) and in the middle (glutamic acid and histidine) of the interface. Such charge distribution helps discriminating between sequences of intermolecular β-strands, of intramolecular β-strands and of β-strands forming β-amyloid fibers. This might open new venues for drug designs and predictive tool developments. Moreover, the β-strands of the cholera toxin B subunit interface, when produced individually as synthetic peptides, are capable of inhibiting the assembly of the toxin into pentamers. Thus, their sequences contain the features necessary for a β-interface formation. Such β-strands could be considered as ‘assemblons’, independent associating units, by homology to the foldons (independent folding unit). Such property would be extremely valuable in term of assembly inhibitory drug development

Sensitivity of MCF-7 mammosphere CSCs to neutron radiation

Aim: Cancer stem cells (CSCs) are highly resistant to chemotherapy and γ-irradiation. Neutrons have a high linear energy transfer, which can lead to extensive damage to the DNA of tumor cells and CSCs. The aim of this work was to compare the sensitivity of MCF-7 human breast adenocarcinoma cells and CSCs to γ- and γ,n-irradiation. Methods: To increase the number of CSCs, MCF-7 cells were cultured as mammospheres. γ-irradiation was carried out in a GUT-200M device (60Co source) in the dose range of 1-8 Gy at a dose rate of 0.75 Gy/min. γ,n-irradiation was carried out in an IR-8 reactor in the dose range of 0.05-2 Gy at a dose rate of 0.06 Gy/min. DNA DSB formation was assessed by the level of γH2AX foci using fluorescence microscopy and flow cytometry. CSCs were identified by flow cytometry as CD44+/CD24-/low cells. Results: We showed that γ,n-irradiation induced the formation of γH2AX foci of a larger size than did γ-irradiation and led to more severe DNA damage per 1 Gy. Moreover, γ,n-radiation was found to have a high relative biological effectiveness (RBE) as assessed by the cell survival rate, the number of CSCs in culture, and the ability of CSCs to repopulate. The highest RBE of neutron radiation was observed at low doses, when cell survival rate decreased by only 5%-10%. With an increase in the radiation dose, the RBE value decreased for all studied parameters, but it remained as high as 5.Conclusion: γ,n-radiation is highly effective against CSCs. Our results explain the efficacy of neutron therapy for resistant forms of breast cancer

Modeling of the deposition of Na Clusters on MgO(001)

International audienc

Structure and optical properties of Na clusters deposited on MgO(001)

We present a hierarchical model for describing Na clusters which interact with a MgO(001) surface. The clusters are treated by time-dependent density-functional theory in full detail and the substrate by classical dynamics of Mg and O ions including dynamical polarizability. The model is calibrated to accurate all-electron density-functional model calculations of a Na adsorbate on an extended model of the MgO(001) surface. We show first applications to structure and optical response of NaNMgO adsorption complexes for N = 3...8. The overall shape of the metal clusters is hardly changed by the interaction of the cluster with the surface while the detailed structure is slightly distorted to accommodate surface corrugation. The peak positions of the Mie plasmon resonances are not shifted, but the spectral fragmentation is strongly influenced by the surface