Prognostic significance of smac/DIABLO in endometrioid endometrial cancer

Apoptosis may occur via a death receptor-dependent or independent (mitochondrial) pathway. The mitochondrial pathway is regulated by small molecules, such as smac/Diablo, which activates caspase cascades. This study examined smac/DIABLO expression in 76 patients with endometrioid endometrial cancers. Presence of smac/DIABLO was quantified by Western blot analysis using nonfixed fresh frozen tissues. Its appearance was found in 55 (72%) of examined tumors. Smac/DIABLO expression significantly correlated with tumor grade (p<0.001). Patients with positive smac/DIABLO tumors had a longer disease-specific survival when compared with those with negative tumors in the 10-year follow-up (p=0.043). The study demonstrated that negative smac/DIABLO expression was a poor prognostic sign.     

Cholesterol as a factor regulating intracellular localization of annexin A6 in Niemann-Pick type C human skin fibroblasts

Lysosome-like storage organelles (LSOs) play a crucial role in excessive accumulation of cholesterol in the Niemann-Pick type C (NPC) disease characterized by altered vesicular traffic of lipids. Annexin A6 (AnxA6) is mainly present in cytosol but upon elevation of [Ca²⁺]_in binds to membranes. In addition, a pH or cholesterol-dependent mechanism of AnxA6 interaction with membranes was described. We found a several fold enrichment of AnxA6 in LSO compartment in fibroblasts isolated from NPC patients in comparison with fibroblasts from healthy individuals. We observed that AnxA6 relocates from cytosol to LSOs in a cholesterol-dependent manner. Cholesterol depletion caused reduction in the binding of AnxA6. Moreover, we found that in NPC cells AnxA6 translocates to the perinuclear region containing late endosomes (LE) loaded with cholesterol. We conclude that AnxA6 may participate in formation of cholesterol-rich platforms on LE and therefore may contribute to the pathology of the NPC disease.     

Replication and partitioning of the broad-host-range plasmid RK2

The broad-host-range plasmid RK2 has been a model for studying DNA metabolism in bacteria for many years. It is used as a vector allowing genetic manipulations in numerous bacterial species. The RK2 genome encodes several genes providing the plasmid with diverse functions allowing for its stable maintenance in a variety of bacterial hosts. This review will focus on two processes indispensable for plasmid DNA maintenance. We will summarize recent understanding of the molecular mechanisms contributing to the RK2 DNA replication and partitioning.     

Ex Vivo Culture of Patient Tissue & Examination of Gene Delivery

This video describes the use of patient tissue as an ex vivo model for the study of gene delivery. Fresh patient tissue obtained at the time of surgery is sliced and maintained in culture. The ex vivo model system allows for the physical delivery of genes into intact patient tissue and gene expression is analysed by bioluminescence imaging using the IVIS detection system. The bioluminescent detection system demonstrates rapid and accurate quantification of gene expression within individual slices without the need for tissue sacrifice. This slice tissue culture system may be used in a variety of tissue types including normal and malignant tissue and allows us to study the effects of the heterogeneous nature of intact tissue and the high degree of variability between individual patients. This model system could be used in certain situations as an alternative to animal models and as a complementary preclinical mode prior to entering clinical trial.Download video file.^{(23M, mov)}     

Organization of the G protein-coupled receptors rhodopsin and opsin in native membranes

G protein-coupled receptors (GPCRs), which constitute the largest and structurally best conserved family of signaling molecules, are involved in virtually all physiological processes. Crystal structures are available only for the detergent-solubilized light receptor rhodopsin. In addition, this receptor is the only GPCR for which the presumed higher order oligomeric state in native membranes has been demonstrated (Fotiadis, D., Liang, Y., Filipek, S., Saperstein, D. A., Engel, A., and Palczewski, K. (2003) Nature 421, 127-128). Here, we have determined by atomic force microscopy the organization of rhodopsin in native membranes obtained from wild-type mouse photoreceptors and opsin isolated from photoreceptors of Rpe65-/- mutant mice, which do not produce the chromophore 11-cis-retinal. The higher order organization of rhodopsin was present irrespective of the support on which the membranes were adsorbed for imaging. Rhodopsin and opsin form structural dimers that are organized in paracrystalline arrays. The intradimeric contact is likely to involve helices IV and V, whereas contacts mainly between helices I and II and the cytoplasmic loop connecting helices V and VI facilitate the formation of rhodopsin dimer rows. Contacts between rows are on the extracellular side and involve helix I. This is the first semi-empirical model of a higher order structure of a GPCR in native membranes, and it has profound implications for the understanding of how this receptor interacts with partner proteins.     

Adaptation of the group A Streptococcus adhesin Scl1 to bind fibronectin type III repeats within wound‐associated extracellular matrix: implications for cancer therapy

The human‐adapted pathogen group A Streptococcus (GAS) utilizes wounds as portals of entry into host tissue, wherein surface adhesins interact with the extracellular matrix, enabling bacterial colonization. The streptococcal collagen‐like protein 1 (Scl1) is a major adhesin of GAS that selectively binds to two fibronectin type III (FnIII) repeats within cellular fibronectin, specifically the alternatively spliced extra domains A and B, and the FnIII repeats within tenascin‐C. Binding to FnIII repeats was mediated through conserved structural determinants present within the Scl1 globular domain and facilitated GAS adherence and biofilm formation. Isoforms of cellular fibronectin that contain extra domains A and B, as well as tenascin‐C, are present for several days in the wound extracellular matrix. Scl1‐FnIII binding is therefore an example of GAS adaptation to the host's wound environment. Similarly, cellular fibronectin isoforms and tenascin‐C are present in the tumor microenvironment. Consistent with this, FnIII repeats mediate GAS attachment to and enhancement of biofilm formation on matrices deposited by cancer‐associated fibroblasts and osteosarcoma cells. These data collectively support the premise for utilization of the Scl1‐FnIII interaction as a novel method of anti‐neoplastic targeting in the tumor microenvironment.     

Species richness of soil gamasid mites (Acari: Mesostigmata) in fire-damaged mountain sites

Gamasid mites are important regulators of soil food webs in forest ecosystems. Wildfire is a dominant disturbance factor in forest ecosystems. We assessed the impact of fire on the species composition of soil gamasid mites at mountain sites following fires of four different degrees of severity and at one control site (5 years post-fire). In total, 14 families, 28 genera, and 54 species or species complexes were found. The abundance and richness were poor in severely burned sites compared to the less damaged sites. The different species compositions, especially in the medium-burned site, require further ecological study to improve our understanding. The fire response and recovery processes of selected species are also discussed.     

Disparity in elevational shifts of European trees in response to recent climate warming

Predicting climate‐driven changes in plant distribution is crucial for biodiversity conservation and management under recent climate change. Climate warming is expected to induce movement of species upslope and towards higher latitudes. However, the mechanisms and physiological processes behind the altitudinal and latitudinal distribution range of a tree species are complex and depend on each tree species features and vary over ontogenetic stages. We investigated the altitudinal distribution differences between juvenile and adult individuals of seven major European tree species along elevational transects covering a wide latitudinal range from southern Spain (37°N) to northern Sweden (67°N). By comparing juvenile and adult distributions (shifts on the optimum position and the range limits) we assessed the response of species to present climate conditions in relation to previous conditions that prevailed when adults were established. Mean temperature increased by 0.86 °C on average at our sites during the last decade compared with previous 30‐year period. Only one of the species studied, Abies alba, matched the expected predictions under the observed warming, with a maximum abundance of juveniles at higher altitudes than adults. Three species, Fagus sylvatica, Picea abies and Pinus sylvestris, showed an opposite pattern while for other three species, such as Quercus ilex, Acer pseudoplatanus and Q. petraea, we were no able to detect changes in distribution. These findings are in contrast with theoretical predictions and show that tree responses to climate change are complex and are obscured not only by other environmental factors but also by internal processes related to ontogeny and demography.