Recognition of Neisseria meningitidis by the Long Pentraxin PTX3 and Its Role as an Endogenous Adjuvant

Long pentraxin 3 (PTX3) is a non-redundant component of the humoral arm of innate immunity. The present study was designed to investigate the interaction of PTX3 with Neisseria meningitidis. PTX3 bound acapsular meningococcus, Neisseria-derived outer membrane vesicles (OMV) and 3 selected meningococcal antigens (GNA0667, GNA1030 and GNA2091). PTX3-recognized microbial moieties are conserved structures which fulfil essential microbial functions. Ptx3-deficient mice had a lower antibody response in vaccination protocols with OMV and co-administration of PTX3 increased the antibody response, particularly in Ptx3-deficient mice. Administration of PTX3 reduced the bacterial load in infant rats challenged with Neisseria meningitidis. These results suggest that PTX3 recognizes a set of conserved structures from Neisseria meningitidis and acts as an amplifier/endogenous adjuvant of responses to this bacterium.     

Analysis of PIK3CA Mutations and Activation Pathways in Triple Negative Breast Cancer

Background

Triple Negative Breast Cancer (TNBC) accounts for 12–24% of all breast carcinomas, and shows worse prognosis compared to other breast cancer subtypes. Molecular studies demonstrated that TNBCs are a heterogeneous group of tumors with different clinical and pathologic features, prognosis, genetic-molecular alterations and treatment responsivity. The PI3K/AKT is a major pathway involved in the regulation of cell survival and proliferation, and is the most frequently altered pathway in breast cancer, apparently with different biologic impact on specific cancer subtypes. The most common genetic abnormality is represented by PIK3CA gene activating mutations, with an overall frequency of 20–40%. The aims of our study were to investigate PIK3CA gene mutations on a large series of TNBC, to perform a wider analysis on genetic alterations involving PI3K/AKT and BRAF/RAS/MAPK pathways and to correlate the results with clinical-pathologic data.

Materials and Methods

PIK3CA mutation analysis was performed by using cobas® PIK3CA Mutation Test. EGFR, AKT1, BRAF, and KRAS genes were analyzed by sequencing. Immunohistochemistry was carried out to identify PTEN loss and to investigate for PI3K/AKT pathways components.

Results

PIK3CA mutations were detected in 23.7% of TNBC, whereas no mutations were identified in EGFR, AKT1, BRAF, and KRAS genes. Moreover, we observed PTEN loss in 11.3% of tumors. Deregulation of PI3K/AKT pathways was revealed by consistent activation of pAKT and p-p44/42 MAPK in all PIK3CA mutated TNBC.

Conclusions

Our data shows that PIK3CA mutations and PI3K/AKT pathway activation are common events in TNBC. A deeper investigation on specific TNBC genomic abnormalities might be helpful in order to select patients who would benefit from current targeted therapy strategies.     

Space radiation research in Europe: flight experiments and ground-based studies

Exposure to space radiation has long been acknowledged as a potential showstopper for long-duration manned interplanetary missions. In an effort to gain more information on space radiation risk and to develop countermeasures, NASA initiated several years ago a Space Radiation Health Program, which is currently supporting biological experiments performed at the Brookhaven National Laboratory. Accelerator-based radiobiology research in the field of space radiation research is also under way in Russia and Japan. The European Space Agency (ESA) supports research in the field in three main directions: spaceflight experiments on the International Space Station; modeling and simulations of the space radiation environment and transport; and, recently, ground-based radiobiology experiments exploiting the high-energy SIS18 synchrotron at GSI in Germany (IBER program). Several experiments are currently under way within IBER, and so far, beams of C and Fe-ions at energies between 11 and 1,000 MeV/n have been used in cell and tissue targets.     

Tissue slice cultures from humans or rodents: a new tool to evaluate biological effects of heavy ions

The aim of this interdisciplinary project is to establish slice culture preparations from rodents and humans as a new model system for studying effects of X-rays and heavy ions within normal and tumor tissues. The advantage of such slice cultures relies on the conservation of an organotypic environment, the easy treatment and observation by live-imaging microscopy, and the independence from genetic immortalization strategies used to generate cell lines. Rat brains as well as human tumors were cut into 300-μm-thick sections and cultivated in an incubator in a humidified atmosphere at 37°C. This is realized by a membrane-based culture system with a liquid–air interface. With this system, it is possible to keep rodent slices viable for several months. Human brain tumor slices remained vital for at least 21 days. Slices were irradiated with X-rays at the radiation facility of the University Hospital in Frankfurt/Main at doses up to 40 Gy. Heavy ion irradiations were performed at GSI (Darmstadt) with different ions, energies, and doses. The irradiated slices were analyzed by 3D-confocal microscopy following immunostaining for DNA damage, microglia, and proliferation markers. The phosphorylated histone γH2AX proved to be suitable for the detection of ion traversals in this system.     

Influence of incubation conditions on the specific methanogenic activity test

The main objective of this work was to evaluate the influence of incubating conditions on the specific methanogenic activity (SMA) test in order to harmonize the test protocol. For this serum bottles were incubated with anaerobic sludge (from UASB reactor treating domestic sewage) in factorial planned experiments which assessed the influence of the temperature, substrate concentration, food/microorganism (F/M) ratio, presence of yeast extract in the medium, as well as type of carbon and nutrient solution. The results showed that the tested methane measuring methods (volumetric with biogas characterization, volumetric with gas wash in alkaline solution, and manometric by using the OxiTop^® system) presented a similar performance. The maintenance of a small gaseous phase volume (e.g. 10% of the total volume) resulted in higher SMA values; and the ideal substrate concentration for the SMA test ranged from 0.5 to 3.0 gCOD/l since higher acetate concentration caused sludge inhibition. The suggested temperature for the test is 35°C and the best F/M ratio varied from 0.125 to 0.750 gCOD/gVS, and this seemed to be the most influent parameter for the SMA test. Finally tests performed with nutrient solution complemented by yeast extract resulted in the highest SMA values.     

Threatened populations of the Australian squirrel glider (Petaurus norfolcensis) show evidence of evolutionary distinctiveness on a Late Pleistocene timescale

The squirrel glider Petaurus norfolcensis occurs across a broad Australian latitudinal range that includes gaps in distribution and potential biogeographic barriers, creating the potential for evolution of distinct entities within this species. Because of the species’ threatened status in the southern part of its range, we tested for the presence of geographically based independent evolutionary units among gliders sampled from southern, and northern coastal populations, using sequences of mitochondrial cytochrome b DNA (mtDNA) and a set of five nuclear microsatellites in 258 individuals. Our analyses suggest that an initial northward colonisation in the early- to mid-Pleistocene was followed by isolation by distance and, eventually, divergence between the sampled coastal and southern populations in the mid- to late-Pleistocene. We propose that the previously large and diverse southern populations have declined coincidentally with the replacement of wet forests by open sclerophyll woodlands during the preceding few million years. By contrast coastal populations further north appear to have been expanding and at present have an effective population size several times greater than southern populations. These results suggest that the two forms are on different evolutionary trajectories and should be treated separately for conservation purposes. It is highly desirable that loss of southern populations be prevented to maintain the unique genetic diversity accumulated over a considerable evolutionary timescale.     

Short-term effects of thyroid hormones during development: Focus on signal transduction

Extranuclear or nongenomic effects of thyroid hormones are mediated by receptors located at the plasma membrane or inside cells, and are independent of protein synthesis. Recently the αVβ3 integrin was identified as a cell membrane receptor for thyroid hormones, and a wide variety of nongenomic effects have now been shown to be induced through binding of thyroid hormones to this receptor. However, also other thyroid hormone receptors can produce nongenomic effects, including the cytoplasmic TRα and TRβ receptors and probably also a G protein-coupled membrane receptor, and increasing importance is now given to thyroid hormone metabolites like 3,5-diiodothyronine and reverse T₃ that can mimick some nongenomic effects of T₃ and T₄. Signal transduction from the αVβ3 integrin may proceed through at least three independent pathways (protein kinase C, Src or mitogen-activated kinases) but the details are still unknown. Thyroid hormones induce nongenomic effects on at least three important Na⁺-dependent transport systems, the Na⁺/K⁺-ATPase, the Na⁺/H⁺ exchanger, and amino acid transport System A, leading to a mitogenic response in embryo cells; but modulation of the same transport systems may have different roles in other cells and at different developmental stages. It seems that thyroid hormones in many cases can modulate nongenomically the same targets affected by the nuclear receptors through long-term mechanisms. Recent results on nongenomic effects confirm the old theory that the primary role of thyroid hormones is to keep the steady-state level of functioning of the cell, but more and more mechanisms are discovered by which this goal can be achieved.     

Extracellular <Emphasis Type="Italic">Paracoccidioides brasiliensis</Emphasis> phospholipase B involvement in alveolar macrophage interaction

Background  

Phospholipase B (PLB) has been reported to be one of the virulence factors for human pathogenic fungi and has also been described as necessary for the early events in infection. Based on these data, we investigated the role of PLB in virulence and modulation of the alveolar pulmonary immune response during infection using an in-vitro model of host-pathogen interaction, i.e. Paracoccidioides brasiliensis yeast cells infecting alveolar macrophage (MH-S) cells.