Frequency of angiotensin II type 1 receptor gene polymorphism in Turkish acute stroke patients

This study was performed in acute stroke patients in the Turkish population to determine the frequency of the A1166C polymorphism in the AT1 gene and to examine the role of this polymorphism in acute stroke development. In this study, 257 genomic DNA samples were analysed (from 206 acute stroke patients and 51 healthy individuals). Genomic DNA was prepared from peripheral blood using the salt‐extraction method. The presence of the A1166C polymorphism in the AT1 gene was determined using the polymerase chain reaction (PCR)‐restriction fragment length polymorphism (RFLP) method. PCR products were separated by 2% agarose gel electrophoresis and visualized by a charge‐coupled device (CCD) camera. In this study, the allele frequency at the A1166C position was 92% A and 8% C for control and 97% A and 3% C for patients. This difference in allele frequency between the control group and the patient group was not statistically significant. However, genotype and allele frequencies showed a significant difference (P < 0.001) in the control and the patient groups. The results of this study show no relationship between the A1166C polymorphism in the AT1 gene and acute stroke in the Turkish population.     

Circadian Variations in the Activities of 6‐Phosphogluconate Dehydrogenase and Glucose‐6‐Phosphate Dehydrogenase in the Liver of Conrol and Streptozotocin‐Induced Diabetic Rats

The aim of this study was to examine: the 24 h variation of 6‐phosphogluconate dehydrogenase and glucose‐6‐phosphate dehydrogenase activities, key enzymes for the maintenance of intracellular NADPH concentration, in rat liver in control and streptozotocin‐induced diabetic animals. Adult male rats were fed ad libitum and synchronized on a 12:12 h light‐dark cycle (lights on 08:00 h). One group of animals was treated with streptozotocin (STZ, 55 mg/kg, intraperitoneal) to induce experimental diabetes. Eight weeks after STZ injection, the animals were sacrificed at six different times of day—1, 5, 9, 13, 17 and 21 Hours After Lights On (HALO)—and livers were obtained. Enzyme activities were determined spectrophotometrically in triplicate in liver homogenates and expressed as units per mg protein. 6‐phosphogluconate dehydrogenase activity was measured by substituting 6‐phosphogluconate as substrate. Glucose‐6‐phosphate dehydrogenase activity was determined by monitoring NADPH production. Treatment, circadian time, and interaction between treatment and circadian time factors were tested by either one or two way analysis of variance (ANOVA). Two‐way ANOVA revealed that 6‐phosphogluconate dehydrogenase activity significantly depended on both the treatment and time of sacrifice. 6‐phosphogluconate dehydrogenase activity was higher in control than diabetic animals; whereas, glucose‐6‐phosphate dehydrogenase activity did not vary over the 24 h in animals made diabetic by STZ treatment. Circadian variation in the activity of 6‐phosphogluconate dehydrogenase was also detected in both the control and STZ treatment groups (one‐way ANOVA). Time‐dependent variation in glucose‐6‐phosphate dehydrogenase activity during the 24 h was detected in control but not in diabetic rats. No significant interaction was detected between STZ‐treatment and time of sacrifice for both hepatic enzyme activities. These results suggest that the activities of NADPH‐generating enzymes exhibit 24 h variation, which is not influenced by diabetes.     

Target-specific delivery of doxorubicin to human glioblastoma cell line via ssDNA aptamer

Targeted drug delivery approaches have been implementing significant therapeutic gain for cancer treatment since last decades. Aptamers are one of the mostly used and highly selective targeting agents for cancer cells. Herein, we address a nano-sized targeted drug delivery approach adorned with A-172 glioblastoma cell-line-specific single stranded DNA (ssDNA) aptamer in which the chemotherapeutic agent Doxorubicin (DOX) had been conjugated. DNA aptamer, GMT-3, was previously selected for specific recognition of glioblastoma and represented many advantageous characteristics for drug targeting purposes. Flow cytometry analysis proved the binding efficiency of the specific aptamer to tumour cell lines. Cell-type-specific toxicity of GMT-3:DOX complex was showed by XTT assay and terminated cytotoxic effects were screened for both target cell and a control breast cancer cell line. The result of this contribution demonstrated the potential utility of GMT-3 aptamer-mediated therapeutic drug transportation in the treatment of gliomas specifically. It was concluded that aptamer-mediated drug delivery can be applied successfully for clinical use.     

Modelling Climate and Societal Resilience in the Eastern Mediterranean in the Last Millennium

This article analyses high-quality hydroclimate proxy records and spatial reconstructions from the Central and Eastern Mediterranean and compares them with two Earth System Model simulations (CCSM4, MPI-ESM-P) for the Crusader period in the Levant (1095–1290 CE), the Mamluk regime in Transjordan (1260–1516 CE) and the Ottoman crisis and Celâlî Rebellion (1580–1610 CE). During the three time intervals, environmental and climatic stress tested the resilience of complex societies. We find that the multidecadal precipitation and drought variations in the Central and Eastern Mediterranean cannot be explained by external forcings (solar variations, tropical volcanism); rather they were driven by internal climate dynamics. Our research emphasises the challenges, opportunities and limitations of linking proxy records, palaeoreconstructions and model simulations to better understand how climate can affect human history.     

Effects of population subdivision and catastrophes on the persistence of a land snail metapopulation

We modeled the dynamics of a metapopulation of the land snail Arianta arbustorum in north-eastern Switzerland to investigate the effect of population subdivision on the persistence of a land snail metapopulation and to analyze the interaction between spatial factors, population subdivision, and catastrophes. We developed a spatially structured, stochastic, age-structured metapopulation model with field data from previous studies on the metapopulation in Switzerland and experimental and meteorological data. The model incorporated distance-dependent dispersal through stream banks, correlated environmental fluctuations, and catastrophes resulting from heavy rains. The results point to various complex interactions among factors involved in metapopulation dynamics and suggest that in some cases population subdivision may act to decrease threats from environmental fluctuations and catastrophes.     

Primary structure of selected archaeal mesophilic and extremely thermophilic outer surface layer proteins

The archaea are recognized as a separate third domain of life together with the bacteria and eucarya. The archaea include the methanogens, extreme halophiles, thermoplasmas, sulfate reducers and sulfur metabolizing thermophiles, which thrive in different habitats such as anaerobic niches, salt lakes, and marine hydrothermals systems and continental solfataras. Many of these habitats represent extreme environments in respect to temperature, osmotic pressure and pH-values and remind on the conditions of the early earth. The cell envelope structures were one of the first biochemical characteristics of archaea studied in detail. The most common archaeal cell envelope is composed of a single crystalline protein or glycoprotein surface layer (S-layer), which is associated with the outside of the cytoplasmic membrane. The S-layers are directly exposed to the extreme environment and can not be stabilized by cellular components. Therefore, from comparative studies of mesophilic and extremely thermophilic S-layer proteins hints can be obtained about the molecular mechanisms of protein stabilization at high temperatures. First crystallization experiments of surface layer proteins under microgravity conditions were successful. Here, we report on the biochemical features of selected mesophilic and extremely archaeal S-layer (glyco-) proteins.     

The contribution of neural crest cells to the nuchal bone and plastron of the turtle shell

The origin of the turtle plastron is not well understood, andthese nine bones have been homologized to the exoskeletal componentsof the clavicles, the interclavicular bone, and gastralia. Earlierdata from our laboratory showed that the plastral bone-formingcells stained positively for HNK-1 and PDGFR, two markers ofskeletogenic neural crest cells. We have now shown that theHNK-1⁺ cells are also positive for p75 and FoxD3, affirmingtheir neural crest identity. These cells originate from thedorsal neural tube of stage-17 turtle embryos, several daysafter the original wave of neural crest cells have migratedand differentiated. Moreover, we have demonstrated the existenceof a staging area, above the neural tube and vertebrae, wherethese late-emigrating neural crest cells collect. After residingin the carapacial staging area, these cells migrate to formthe plastral bones. We also demonstrate that one bone of thecarapace, the nuchal bone, also stains with HNK-1 and with antibodiesto PDGFR. The nuchal bone shares several other properties withthe plastral bones, suggesting that it, too, is derived fromneural crest cells. Alligator gastralia stain for HNK-1, whiletheir ribs do not, thus suggesting that the gastralial precursormay also be derived from neural crest cells.