Measuring the size of biological nanostructures with spatially modulated illumination microscopy

Spatially modulated illumination fluorescence microscopy can in theory measure the sizes of objects with a diameter ranging between 10 and 200 nm and has allowed accurate size measurement of subresolution fluorescent beads ( approximately 40-100 nm). Biological structures in this size range have so far been measured by electron microscopy. Here, we have labeled sites containing the active, hyperphosphorylated form of RNA polymerase II in the nucleus of HeLa cells by using the antibody H5. The spatially modulated illumination-microscope was compared with confocal laser scanning and electron microscopes and found to be suitable for measuring the size of cellular nanostructures in a biological setting. The hyperphosphorylated form of polymerase II was found in structures with a diameter of approximately 70 nm, well below the 200-nm resolution limit of standard fluorescence microscopes.     

Anti-inflammatory non-steroidal drug able to modulate IL-10 in allergic asthma

Our studies target alternative/adjuvant therapies in allergic diseases, able to qualitatively/quantitatively modify cytokine profiles produced by both CD4+ T-cell subsets (mainly Th1 and Th2) and B-cells, macrophages, etc. Current investigations aim to identify compounds capable to down-regulate IL-10 as an exponent of Th2 cell function and, consequently, to up-regulate Th1 cytokine levels. Experiments on ten allergic asthmatic patients and ten healthy subjects as control were performed. Cytokine production, triggered in PBMCs culture systems by PHA, was modulated with Indomethacin, a non-steroidal anti-inflammatory drug and IL-10 was measured in 24 hours culture supernatants. According to our experimental data, IL-10 level of asthmatic patients' PBMCs in the resting state is not significantly different from control. PHA-activated PBMCs from asthmatic patients do not display significantly higher IL-10 levels than the normal subjects. The results obtained up-to-date reveal the fact that Indomethacin strongly down-regulates IL-10 levels in PBMCs cultures, in both asthmatic allergic patients and healthy subjects. It is obvious that the inhibitory effect of Indomethacin on IL-10 released by PBMCs is higher in the case of allergic asthmatic patients. The results obtained in this study demonstrate that Indomethacin is a possible therapeutic candidate in allergic asthma.     

Retrovirally mediated IFN-beta transduction of macrophages induces resistance to HIV, correlated with up-regulation of RANTES production and down-regulation of C-C chemokine receptor-5 expression

Constitutive expression of IFN-beta by HIV target cells may be an alternative or complementary therapeutic approach for the treatment of AIDS. We show that macrophages derived from CD34+ cells from umbilical cord blood can be efficiently transduced by a retroviral vector carrying the IFN-beta coding sequence. This results in resistance to infection by a macrophage-tropic HIV type 1, as shown by the drastic reduction in the HIV DNA copy number per cell and in p24 release. Moreover, IFN-beta transduction totally blocked secretion of proinflammatory cytokines after HIV infection. The constitutive IFN-beta production also resulted in an increased production of IL-12 and IFN-gamma Th1-type cytokines and of the beta-chemokines macrophage-inflammatory protein-1alpha, macrophage-inflammatory protein-1beta, and RANTES. RANTES was found to be involved in the HIV resistance observed, and this was correlated with a down-regulation of the CCR-5 HIV entry coreceptor. These results demonstrate the feasibility and the efficacy of such IFN-beta-mediated gene therapy. In addition to inhibiting HIV replication, IFN-beta transduction could have beneficial immune effects in HIV-infected patients by favoring cellular immune responses.     

Spatial Distributions of Early and Late Replicating Chromatin in Interphase Chromosome Territories

The surface area of chromosome territories has been suggested as a preferred site for genes, specific RNAs, and accumulations of splicing factors. Here, we investigated the localization of sites of replication within individual chromosome territories.In vivoreplication labeling with thymidine analogues IdUrd and CldUrd was combined with chromosome painting by fluorescentin situhybridization on three-dimensionally preserved human fibroblast nuclei. Spatial distributions of replication labels over the chromosome territory, as well as the territory volume and shape, were determined by 3D image analysis. During late S-phase a previously observed shape difference between the active and inactive X-chromosome in female cells was maintained, while the volumes of the two territories did not differ significantly. Domains containing early or mid to late replicating chromatin were distributed throughout territories of chromome 8 and the active X. In the inactive X-chromosome early replicating chromatin was observed preferentially near the territory surface. Most important, we established that the process of replication takes place in foci throughout the entire chromosome territory volume, in early as well as in late S-phase. This demonstrates that activity of macromolecular enzyme complexes takes place throughout chromosome territories and is not confined to the territory surface as suggested previously.     

Evidence against a Looped Structure of the Inactive Human X-Chromosome Territory

Multicolor fluorescencein situhybridization with a whole chromosome composite probe for the X-chromosome and microdissection probes for the Xp and Xq arms, as well as for the Xp terminal, Xq terminal, and X centromer specific subregional probes, was applied to three-dimensional (3D) preserved human female amniotic fluid cell nuclei. Confocal laser scanning microscopy and three-dimensional image analysis demonstrated distinctly separated Xp arm and Xq arm domains. 3D distance measurements revealed a high variability of intrachromosomal distances between Xpter, Xcen, and Xqter specific probes within both X territories. A 3D distance measurement error of ±70 nm was found in control experiments using quartz glass microspheres labeled with different fluorochromes. Our data argue against the hypothesis of Walkeret al.(1991,Proc. Natl. Acad. Sci. USA88, 6191–6195) that a looped structure of the inactive X territory is formed by tight telomere–telomere associations.     

A purified green barley extract with modulatory properties upon TNF alpha and ROS released by human specialised cells isolated from RA patients

Based on the finding that reactive oxygen species (ROS) play important roles in mediating proinflammatory cytokine production (e.g. TNF alpha) and that many plant extracts contain substances with antioxidant properties, we examined the antiinflammatory action of a green barley extract, commercially available as "Natural SOD". The results obtained in this study demonstrate that the antiinflammatory properties of "Natural SOD" due to its micromolecular substances, able to scavenge ROS and to down-regulate TNF alpha production, main inflammation mediators produced by specialised cells from peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA). We prepared and tested a purified green barley extract (PE) containing micromolecular substances under 1 kDa, able to inhibit TNF alpha releasing--measured by an bioassay--from LPS stimulated human mononuclear cells (MNC) isolated both from PB and SF of RA patients. Luminol-dependent chemiluminescence has been used to measure the scavenging activity of PE on ROS releasing from activated neutrophils isolated from PB of RA patients. PE, containing high concentrations of substances with antioxidant and antiinflammatory properties, could be a more efficient natural drug for human use than "Natural SOD" in the treatment of RA patients.     

Social prophylaxis: group interaction promotes collective immunity in ant colonies

Life in a social group increases the risk of disease transmission. To counteract this threat, social insects have evolved manifold antiparasite defenses, ranging from social exclusion of infected group members to intensive care. It is generally assumed that individuals performing hygienic behaviors risk infecting themselves, suggesting a high direct cost of helping. Our work instead indicates the opposite for garden ants. Social contact with individual workers, which were experimentally exposed to a fungal parasite, provided a clear survival benefit to nontreated, naive group members upon later challenge with the same parasite. This first demonstration of contact immunity in Social Hymenoptera and complementary results from other animal groups and plants suggest its general importance in both antiparasite and antiherbivore defense. In addition to this physiological prophylaxis of adult ants, infection of the brood was prevented in our experiment by behavioral changes of treated and naive workers. Parasite-treated ants stayed away from the brood chamber, whereas their naive nestmates increased brood-care activities. Our findings reveal a direct benefit for individuals to perform hygienic behaviors toward others, and this might explain the widely observed maintenance of social cohesion under parasite attack in insect societies.