Relative accuracy of spatial predictive models for lynx Lynx canadensis derived using logistic regression-AIC,multiple criteria evaluation and Bayesian approaches

We compared probability surfaces derived using one set of environmental variables in three Geographic Information Systems (GIS) -based approaches: logistic regression and Akaike's Information Criterion (AIC),Multiple Criteria Evaluation (MCE),and Bayesian Analysis (specifically Dempster-Shafer theory). We used lynx Lynx canadensis as our focal species,and developed our environment relationship model using track data collected in Banff National Park,Alberta,Canada,during winters from 1997 to 2000. The accuracy of the three spatial models were compared using a contingency table method. We determined the percentage of cases in which both presence and absence points were correctly classified (overall accuracy),the failure to predict a species where it occurred (omission error) and the prediction of presence where there was absence (commission error). Our overall accuracy showed the logistic regression approach was the most accurate (74.51% ). The multiple criteria evaluation was intermediate (39.22%),while the Dempster-Shafer (D-S) theory model was the poorest (29.90%). However,omission and commission error tell us a different story: logistic regression had the lowest commission error,while D-S theory produced the lowest omission error. Our results provide evidence that habitat modellers should evaluate all three error measures when ascribing confidence in their model. We suggest that for our study area at least,the logistic regression model is optimal. However,where sample size is small or the species is very rare,it may also be useful to explore and/or use a more ecologically cautious modelling approach (e.g. Dempster-Shafer) that would over-predict,protect more sites,and thereby minimize the risk of missing critical habitat in conservation plans.     

Endothelial Dysfunction and Metabolic Effects of Nitric Oxide in Humans

Shortage of nitric oxide (NO) is believed to be a key factor in the development of endothelial dysfunction. Metabolic effects of NO were analyzed in subjects with multiple metabolic disorders (essential arterial hypertension, platelet hyperaggregability, and hypercholesterolemia). Effects of the NO-inducing ₁-adrenoblocker nebivolol on the blood rheology and lipid profile were studied in pilots regularly exposed to factors of flying work contributing to the development of endotheliocyte dysfunction. The dynamics of spontaneous platelet aggregation in pilots with arterial hypertension suggested that nebivolol produced a statistically significant general effect on platelets, reducing their baseline activation by eliminating endothelial dysfunction. This NO-inducing drug has an antiatherosclerotic effect. Metabolic effects of NO are essential for normalizing endothelial functions because this messenger interacts with key reactions of the pathogenic cascade in the cardiovascular continuum.     

Molecular mechanisms of hormonal activity. I. receptors. neuromediators. systems with second messengers

Hormone signal transfer along all of the cell compartments including nucleus is powered by signal transduction systems. Characteristics and importance of hormone receptors, principal components, functional mechanisms, and biological role of different systems with second messengers are described. Considerable examples of the importance of these systems for medicine are adduced. The drugs modifying these systems comprise more than 65% of contemporary medicines.Translated from Biokhimiya, Vol. 70, No. 1, 2005, pp. 33–50.Original Russian Text Copyright © 2005 by Kulinsky, Kolesnichenko.     

Sequence, organization, and evolution of the A+T region of Drosophila melanogaster mitochondrial DNA

The long (4.6-kb) A+T region of Drosophila melanogaster mitochondrial DNA has been cloned and sequenced. The A+T region is organized in two large arrays of tandemly repeated DNA sequence elements, with nonrepetitive intervening and flanking sequences comprising only 22% of its length. The first repeat array consists of five repeats of 338-373 bp. The second consists of four intact 464-bp repeats and a fifth partial repeat of 137 bp. Three DNA sequence elements are found to be highly conserved in D. melanogaster and in several Drosophila species with short A+T regions. These include a 300-bp DNA sequence element that overlaps the DNA replication origin and two thymidylate stretches identified on opposite DNA strands. We conclude that the length heterogeneity observed in the A+T regulatory region in mitochondrial DNAs from the genus Drosophila results from the expansion (and contraction) of the number of repeated DNA sequence elements. We also propose that the 300-bp conserved DNA sequence element, in conjunction with another primary sequence determinant, perhaps the adjacent thymidylate stretch, functions in the regulation of mitochondrial DNA replication.      

Activation of morphogenesis and proliferation by low specificity chemical effectors

Activation of highly specific biochemical processes by simple chemical agents is demonstrated for morphogenesis (anlage and development of female gametophyte in cereal) and mitosis (in cell cultures and animal and plant tissues). The effects of these agents are tissue-specific. Structure--activity relationship is analyzed in this group of compounds. Thus, the phenomenon reveals the exact pathways of the influence of allelopathic and anthropogenic chemical agents on evolution of plant biocenoses.     

Diffusion of low density lipoprotein-receptor complex on human fibroblasts

Diffusion of the complex consisting of low density lipoprotein (LDL) bound to its receptor on the surface of human fibroblasts has been measured with the help of an intensely fluorescent, biologically active LDL derivative, dioctadecylindocarbocyanine LDL (dil(3)-LDL). Fluorescence photobleaching recovering and direct video observations of the Brownian motion of individual LDL-receptor complexes yielded diffusion coefficients for the slow diffusion on cell surfaces and fast diffusion on membrane blebs, respectively. At 10 degrees C, less that 20 percent of the LDL-receptor complex was measurably diffusible either on normal human fibroblasts GM-3348 or on LDL-receptor- internalization-defective J.D. cells GM-2408A. At 21 degrees and 28 degrees C, the diffusion fractions of approximately 75 and 60 percent, respectively, on both cell lines. The lipid analog nitrobenzoxadiazolephosphatidylcholine (NBD-PC) diffused in the GM-2408A cell membrane at 1.5x10(-8) cm(2)/sec at 22 degrees C. On blebs induced in GM-2408A cell membranes, the dil(3)-LDL receptor complex diffusion coefficient increased to approximately 10(-9) cm(2)/s, thus approaching the maximum theoretical predictions for a large protein in the viscous lipid bilayer. Cytoskeletal staining of blebs with NBD- phallacidin, a fluorescent probe specific for F-actin, indicated that loss of the bulk of the F-actin cytoskeleton accompanied the release of the natural constraints on later diffusion observed on blebs. This work shows that the internalization defect of J.D. is not due to immobilization of the LDL-receptor complex since its diffusibility is sufficient to sustain even the internalization rates observed in the native fibroblasts. Nevertheless, as with many other cell membrane receptors, the diffusion coefficient of the LDL-receptor complex is at least two orders of magnitude slower on native membrane than the viscous limit approached on cell membrane blebs where it is released from lateral constraints. However, LDL-receptor diffusion may not limit LDL internalization in normal human fibroblasts.     

The possibility of using characters of the female genital armature for species diagnostics and classification of the genus <Emphasis Type="Italic">Mellicta Billberg</Emphasis>, 1820 (Lepidoptera,Nymphalidae): 1. <Emphasis Type="Italic">Mellicta athalia</Emphasis> (Rottemburg, 1775) species group

The morphology of female genital armature of seven species of the genus Mellicta belonging to the M. athalia species-group from different localities of their ranges is analyzed. The main distinctive features are described and their variability and use for species identification are assessed. It is shown that some characteristics of female genitalia can be used to clarify the systematic position of species within the genus. Keys to species of the athalia group based on female genitalia are given.     

Plant stress uncoupling protein CSP 310 caused thermogenesis in winter wheat mitochondria in vitro

The addition of plant stress uncoupling protein CSP 310 has been found to increase thermogenesis in isolated winter wheat mitochondriain vitro during cold stress. On the other hand, the addition of anti-CSP 310 antiserum has been found to decrease thermogenesis in isolated winter wheat mitochondria. This result corresponds well to data about the influence of mitochondria incubation with CSP 310 and anti-CSP 310 antiserum on their energetic activity. It is supposed that CSP 310 uncouples the oxidative phosphorylation in mitochondria that causes thermogenesis during cold stress.     

Influence of CSP 310 and CSP 310-like proteins from cereals on mitochondrial energetic activity and lipid peroxidation in vitro and in vivo

Background  

The development of chilling and freezing injury symptoms in plants is known to frequently coincide with peroxidation of free fatty acids. Mitochondria are one of the major sources of reactive oxygen species during cold stress. Recently it has been suggested that uncoupling of oxidation and phosphorylation in mitochondria during oxidative stress can decrease ROS formation by mitochondrial respiratory chain generation. At the same time, it is known that plant uncoupling mitochondrial protein (PUMP) and other UCP-like proteins are not the only uncoupling system in plant mitochondria. All plants have cyanide-resistant oxidase (AOX) whose activation causes an uncoupling of respiration and oxidative phosphorylation. Recently it has been found that in cereals, cold stress protein CSP 310 exists, and that this causes uncoupling of oxidation and phosphorylation in mitochondria.