Continuous wave and simulated GSM exposure at 1.8 W/kg and 1.8 GHz do not induce hsp16-1 heat-shock gene expression in Caenorhabditis elegans

Recent data suggest that there might be a subtle thermal explanation for the apparent induction by radiofrequency (RF) radiation of transgene expression from a small heat-shock protein (hsp16-1) promoter in the nematode, Caenorhabditis elegans. The RF fields used in the C. elegans study were much weaker (SAR 5-40 mW kg(-1)) than those routinely tested in many other published studies (SAR approximately 2 W kg(-1)). To resolve this disparity, we have exposed the same transgenic hsp16-1::lacZ strain of C. elegans (PC72) to higher intensity RF fields (1.8 GHz; SAR approximately 1.8 W kg(-1)). For both continuous wave (CW) and Talk-pulsed RF exposures (2.5 h at 25 degrees C), there was no indication that RF exposure could induce reporter expression above sham control levels. Thus, at much higher induced RF field strength (close to the maximum permitted exposure from a mobile telephone handset), this particular nematode heat-shock gene is not up-regulated. However, under conditions where background reporter expression was moderately elevated in the sham controls (perhaps as a result of some unknown co-stressor), we found some evidence that reporter expression may be reduced by approximately 15% following exposure to either Talk-pulsed or CW RF fields.     

The concentration of kynurenine in rat model of asthma

Asthma is a chronic inflammatory disease that involves the immune system activation. Evidence is accumulating about the role of kynurenine pathway in the immune system regulation. The kynurenine pathway includes several metabolites of tryptophan, among others kynurenine (KYN). To study the immunological system regulation in asthma a simple and sensitive models of asthma are required. In the present study we induced rat model of asthma using ovalbumin (OVA) sensitization followed by challenge with OVA. The development of asthma has been confirmed by plasma total IgE measurement and the histological examination. The concentration of KYN has been determined in plasma, lungs and liver by high-performance liquid chromatography (HPLC). In OVA sensitized rats the concentration of total IgE was statistically significantly increased as compared to VEH sensitized control groups (437.6 +/- 97.7 kU/l vs 159.2 +/- 22.7 kU/l, respectively; p< 0.01). In asthmatic animals, the number of eosinophils, neutrophils and mast cells increased considerably, and epithelial lesion and the increase in airway epithelium goblet cells and edema of bronchial mucosa were present. We did not observe any significant changes in the concentration of KYN in plasma, lungs or liver between studied groups. In conclusion, the concentration of KYN remains unchanged in asthmatic animals as compared to control groups. Further studies using rat model of asthma are warranted to establish the role of kynurenine pathway regulation in asthma.     

Study of Cu chemical state inside single neurons from Parkinson's disease and control substantia nigra using the micro-XANES technique

Parkinson's disease (PD) is referred to as idiopathic disorder, which means that its causes have not been found yet. However, a few processes such as oxidative stress, protein aggregation and mitochondrial dysfunction are suspected to lead to the atrophy and death of substantia nigra (SN) neurons in case of this neurodegenerative disorder. Cu is a trace element whose role in the pathogenesis of PD is widely discussed. The investigation of Cu oxidation state inside single nerve cells from SN of PD and control cases may shed some new light on the role of this element in PD. The differences in Cu chemical state were investigated with the use of X-ray absorption near edge structure (XANES) spectroscopy. The least-square fitting method was applied for the analysis of XANES spectra. The comparison of the positions of white line, multiple scattering and pre-edge peak maximum at the energy scale did not reveal the existence of differences in Cu chemical state between PD and control samples. However, it was found that most of the Cu inside SN neurons occurs in tetrahedral environment and probably as Cu(II).     

Cortisol is a suppressor of apoptosis in bovine corpus luteum

Glucocorticoid (GC) acts as a modulator of physiological functions in several organs. In the present study, we examined whether GC suppresses luteolysis in bovine corpus luteum (CL). Cortisol (an active GC) reduced the mRNA expression of caspase 8 (CASP8) and caspase 3 (CASP3) and reduced the enzymatic activity of CASP3 and cell death induced by tumor necrosis factor (TNF) and interferon gamma (IFNG) in cultured bovine luteal cells. mRNAs and proteins of GC receptor (NR3C1), 11beta-hydroxysteroid dehydrogenase type 1 (HSD11B1), and HSD11B2 were expressed in CL throughout the estrous cycle. Moreover, the protein expression and the enzymatic activity of HSD11B1 were high at the early and the midluteal stages compared to the regressed luteal stage. These results suggest that cortisol suppresses TNF-IFNG-induced apoptosis in vitro by reducing apoptosis signals via CASP8 and CASP3 in bovine CL and that the local increase in cortisol production resulting from increased HSD11B1 at the early and midluteal stages helps to maintain CL function by suppressing apoptosis of luteal cells.     

Tolerance Analysis for Design of Multistage Manufacturing Processes Using Number-Theoretical Net Method (NT-net)

Recent developments in modeling stream of variation in multistage manufacturing system along with the urgent need for yield enhancement in the semiconductor industry has led to complex large scale simulation problems in design and performance prediction, thus challenging current Monte Carlo (MC) based simulation techniques. MC method prevails in statistical simulation approaches for multi-dimensional cases with general (i.e., non-Gaussian) distributions and/or complex response functions. A method is proposed based on number theory (NT-net) to reduce computing effort and the variability of MC's results in tolerance design and circuit performance simulation. The sampling strategy is improved by introducing NT-net that can provide better convergent rate over MC. The new method is presented and verified using several case studies, including analytical and industrial cases of a filter design and analyses of a four-bar mechanism. Results indicate a 90–95% reduction of computation effort with significant improvement in accuracy that can be achieved by the proposed technique.     

Predation-mediated coexistence of large- and small-bodied Daphnia at different food levels

Using an individual-based age-structured population model (a combination of O'Brien's apparent-prey-size approach, Eggers's reactive-field-volume model, and Holling's disk equation), we could predict that (1) a Daphnia population could be kept at low density by fish predation irrespective of food level, with greater recruitment at higher food being instantly compensated for by raised mortality reflecting increased predation, and (2) Daphnia density levels are species specific and inversely related to both body size at first reproduction and the reaction distance at which a foraging fish sees its Daphnia prey. These two hypotheses were experimentally tested in outdoor mesocosms with two Daphnia species of different body sizes grown in the absence or presence of fish that were allowed to feed for 2-3 h each evening. While each Daphnia quickly reached high density with reproduction halted by food limitation in the absence of fish, the populations stayed at much lower species-specific density levels, similar in low and high food concentrations, in the presence of fish. This suggests that our model offers a reasonable mechanistic explanation for the coexistence of large- and small-bodied zooplankton in proportions reflecting their body sizes throughout habitats comprising a wide productivity spectrum, with each species at a density level at which it becomes included in a predator's diet.     

Alignments grow, secondary structure prediction improves.

Using information from sequence alignments significantly improves protein secondary structure prediction. Typically, more divergent profiles yield better predictions. Recently, various groups have shown that accuracy can be improved significantly by using PSI-BLAST profiles to develop new prediction methods. Here, we focused on the influences of various alignment strategies on two 8-year-old PHD methods. The following results stood out. (i) PHD using pairwise alignments predicts about 72% of all residues correctly in one of the three states: helix, strand, and other. Using larger databases and PSI-BLAST raised accuracy to 75%. (ii) More than 60% of the improvement originated from the growth of current sequence databases; about 20% resulted from detailed changes in the alignment procedure (substitution matrix, thresholds, and gap penalties). Another 20% of the improvement resulted from carefully using iterated PSI-BLAST searches. (iii) It is of interest that we failed to improve prediction accuracy further when attempting to refine the alignment by dynamic programming (MaxHom and ClustalW). (iv) Improvement through family growth appears to saturate at some point. However, most families have not reached this saturation. Hence, we anticipate that prediction accuracy will continue to rise with database growth.     

Campylocentrum guarinae sp. nov. (Vandeae,Orchidaceae) from Colombia

A new species of Campylocentrum from the Colombian Andes, C. guarinae, is described, illustrated and placed within a key to Colombian species of the genus. The new species resembles C. lansbergii from which it differs in vegetative and floral characters. The main differences between these species are described and illustrated.