The self-association of zinc-free human insulin and insulin analogue B13-glutamine

The self-association of Zn-free human insulin, Zn-free insulin analogue B13-glutamine, 2-Zn insulin and cobalt(III) human insulin in the millimolar concentration range has been investigated by measuring the osmotic pressure at pH 7.5 in 0.05 M NaCl, 25 degrees C. The pH dependence of association has been measured in the pH range 6.8-9. For all insulins, except Zn-free human insulin, the major association state has been found to be the hexamer. Maximal association of hexamer has been observed for Zn-free human insulin at high concentration (2-7 mM) and physiological pH. At concentrations less than 1 mM and pH greater than 7.0, dissociation to a lower state than the hexamer is found. The conclusion has been drawn that, in the absence of metal ions, human insulin and insulin analogue B13-glutamine associate to the hexamer in the physiological pH range at concentrations in the millimolar range.     

Photoluminescence band and anti-Stokes emission of native collagen in the visible range of the spectrum]

Photoluminescence (PL) of collagen, phenylalanine and tyrosine has been experimentally studied in the range of 400-700 nm. Anti-Stokes emission was observed when PL was excited by visible light. Possible participation of an excimer in generation of PL was shown. It has been pointed out that phenylalanine chromophore plays a dominant role in fluorescence generation of collagen in the spectrum visible range.     

Application of satellite collars to the study of home range and activity of the Amur tiger (<Emphasis Type="Italic">Panthera tigris altaica</Emphasis>)

The possibility of application of satellite collars to the study of home range and activity of Amur tigers has been analyzed. The possibility of obtaining information about the size and structure of a home range, discerning the home range core areas, seasonal changes in the use of space by tigers, and collecting detailed data on animals’ activity and characteristics of the use of different elements of landscape and terrain has been demonstrated. In contrast to VHF transmitters, satellite collars allow tigers to be tracked even in the cases of very long travels.     

Enhanced instrumental sensitivity and selectivity for aminopeptidase profiling

Laser-excited fluorimetry has been applied to the identification of bacteria and fungus. The instrumental sensitivity and selectivity of the aminopeptidase profiling method has been enhanced by the use of laser excitation in conjunction with improved spectral and temporal background rejection. The linear dynamic range for the aminopeptidase technique has been increased by achieving a reduced lower limit of detection of the fluorescent tag, beta-naphthylamine. Standard aminopeptidase methodology only provides a linear dynamic range of 1.5 orders of magnitude. The laser-based method expanded the range to three orders of magnitude allowing the inherent specificity of aminopeptidase enzymes within the pathogen to be observed. The enhanced linear dynamic range was observed in profiles of Agrobacterium tumefaciens rubi and Phytophthora megasperma var. sojae.     

Distinct features of intraspecific and intrapopulation variability of the skull size in the red fox

The range of chronographic variability of the average size of the skull in the red fox (data collected by the authors) from a compact area in the Middle Urals has been assessed for a 30-year period, and the results obtained have been compared with the published data on the geographical variability within the vast species range. The range of changes of the average dimensions of the skull over time spanned almost the entire range of geographical variability. Therefore, the problem of search for factors that determine the morphological diversity arises.     

Seven decades of southern range dynamics of Canada lynx

The range of the Canada lynx (Lynx canadensis) has contracted substantially from its historical range. Using harvest records, we found that the southern range of the lynx in Ontario in the late 1940s collapsed and then, in a short period of time, increased to its largest extent in the mid‐1960s when the lynx range spread south of the boreal forest for a decade. After this expansion, the southern range contracted northwards beginning in the 1970s. Most recently, there has been a slight expansion between 2010 and 2017. We have attributed these dynamics on the southern range periphery to the fluctuation of the boreal lynx population in the core of the species'' range. In addition, connectivity to boreal lynx populations and snow depth seemed to condition whether the lynx expanded into an area. However, we did not find any evidence to suggest that these changes were due to anthropogenic landscape disturbances or competition. The boreal lynx population does not reach the peak abundance it once did, without which we would not expect to see large expansions of the southern lynx range as in the mid‐1960s. Our results suggest that the southern lynx range in Ontario has been driven by the magnitude of the boreal lynx population cycle, connectivity to the boreal forest, and snow conditions. Future persistence of lynx in the southern range periphery will likely depend on dynamics in the range core.     

Effects of dietary restriction on lifespan,growth, and reproduction of the clam shrimp Eulimnadia texana

Hydrobiologia - Diet has been linked to lifespan in a broad range of animals. In particular, pronounced caloric restriction has been associated with increased longevity. Herein, the relationship of...     

Method for analysis of polybrominated biphenyls by gas chromatography mass spectrometry

Gas chromatography using a short packed column (45 cm, 0.2 cm i.d., 2% OV-101 on Gas-Chrom Q) with mass spectrometric detection in the selected ion monitoring mode has been found satisfactory for the analysis of lower as well as higher polybrominated biphenyls. Acceptable sensitivity (< 1 ng) may be achieved for this method by focusing selectively at either the low (m/z 20-600) or the high m/z 600-1000) range of the quadrupole filter (low range for mono- through hexabromobiphenyl, high range for hexa- through decabromobiphenyl). A tuning technique has been developed for low range and high range polybrominated biphenyls using the ion abundances of perfluorotributylamine as a standard. Standard ions for the quantitation of mono- through decabromo-biphenyls were selected and validated. The technique was applied to the analysis of a variety of environmental samples.     

Coordination of calcium by iron enterobactin

Iron(III) enterobactin has been shown to coordinate alkaline earth metals. By studying a range of enterobactin analogues it has been possible to propose a structure for this complex type. These observations are discussed.     

Pseudotypes of vesicular stomatitis virus with the envelope properties of mammalian and primate retroviruses.

By employing improved techniques it has been possible to produce and characterize a representative spectrum of mammalian and primate retrovirus pseudotypes of vesicular stomatitis virus (VSV). Selection of appropriate cell lines for both the production and subsequent detection of the VSV pseudotypes has been the most important factor in permitting their demonstration. The host range for penetration of these retrovirus pseudotypes of VSV has been defined and found to differ from that reported for the replication of the corresponding retroviruses. Additionally, retroviruses having an identical host range for replication were distinguishable by differences in their host range for penetration, implying that restriction of replication may be occurring by different mechanisms. Studies of the plaque-forming efficiency of retrovirus pseudotypes of VSV in cell lines nonpermissive for replication of the corresponding retroviruses permitted a distinction to be made between the restriction of replication occurring as a consequence of postpenetration events and that occurring as a consequence of a block of penetration itself. The demonstration of primate retrovirus pseudotypes of VSV permits the use of VSV as a probe for the detection of this group of viruses.     

Dynamics of charge carrier transfer in a DNA molecule

An equivalent electric circuit has been developed which describes the charge transfer in DNA molecule. A computer simulation of the charge carrier transfer dynamics in the molecule has been performed based on this circuit. It was found that the switching time of a molecular junction lies in the femtosecond range and depends on the frequency of the input electric signal. An increase in the frequency of the input signal in the range from 1 GHz to 4 THz and a reduction of temperature lead to a decrease in the current passing through the DNA molecule. It has been shown that the sequence of the DNA base pairs defines the rate of localization and delocalization of holes and controls the signal propagation rate in the DNA molecule.     

Array biosensor for detection of biohazards

A fluorescence-based biosensor has been developed for simultaneous analysis of multiple samples for multiple biohazardous agents. A patterned array of antibodies immobilized on the surface of a planar waveguide is used to capture antigen present in samples; bound analyte is then quantified by means of fluorescent tracer antibodies. Upon excitation of the fluorophore by a small diode laser, a CCD camera detects the pattern of fluorescent antibody:antigen complexes on the waveguide surface. Image analysis software correlates the position of fluorescent signals with the identity of the analyte. This array biosensor has been used to detect toxins, toxoids, and killed or non-pathogenic (vaccine) strains of pathogenic bacteria. Limits of detection in the mid-ng/ml range (toxins and toxoids) and in the 10(3)-10(6) cfu/ml range (bacterial analytes) were achieved with a facile 14-min off-line assay. In addition, a fluidics and imaging system has been developed which allows automated detection of staphylococcal enterotoxin B (SEB) in the low ng/ml range.     

A review of detection range testing in aquatic passive acoustic telemetry studies

Passive acoustic telemetry provides an important tool to study the spatial ecology and behaviour of organisms in marine and freshwater systems, but understanding the detection range of acoustic receivers is critical for interpreting acoustic data and establishing receiver spacing to maximize study efficiency. This study presents a comprehensive review of how acoustic detection range has been considered and assessed to date, summarizes important variables to monitor when determining the detection range of a receiver array, and provides recommendations to account for detection range during experimental design, analysis and data interpretation. A total of 378 passive acoustic telemetry studies (1986–2012) were scored against a set of pre-defined criteria to provide a standardized assessment of how well detection range was accounted for, from a maximum possible score of 45. Scores ranged from 0 to 39 (11.1 ± 0.4; mean ± 1 SE). Over the past decade mean scores have been consistently between 6.7 and 12.9 which indicates that detection range has not been adequately considered in most contemporary acoustic telemetry studies. Given the highly variable nature of detection range over space and time, it is necessary to create a culture of detection range testing among the scientific community. For robust telemetry studies it is recommended that consideration of detection range should be given a greater focus within study design, execution and data analysis. To aid array design in new systems, short-term detection range tests should be conducted in the most representative area of the study system prior to deployment. As well, fixed distance sentinel tags should ideally be deployed at a representative receiver site within the array to provide a continuous assessment of detection range and influential environmental parameters should be monitored to facilitate modeling of detection range variability over time. When warranted, data analysis should incorporate modeled variation in detection ranges.     

Is protein folding rate dependent on number of folding stages? Modeling of protein folding with ferredoxin-like fold

Statistical analysis of protein folding rates has been done for 84 proteins with available experimental data. A surprising result is that the proteins with multi-state kinetics from the size range of 50–100 amino acid residues (a.a.) fold as fast as proteins with two-state kinetics from the same size range. At the same time, the proteins with two-state kinetics from the size range 101–151 a.a. fold faster than those from the size range 50–100 a.a. Moreover, it turns out unexpectedly that usually in the group of structural homologs from the size range 50–100 a.a., proteins with multi-state kinetics fold faster than those with two-state kinetics. The protein folding for six proteins with a ferredoxin-like fold and with a similar size has been modeled using Monte Carlo simulations and dynamic programming. Good correlation between experimental folding rates, some structural parameters, and the number of Monte Carlo steps has been obtained. It is shown that a protein with multi-state kinetics actually folds three times faster than its structural homologs.     

A mathematical model of the flow in the circle of Willis

A mathematical model of the flow in the circle of Willis has been designed and the effects of (a) the large anatomical variation of the communicating arteries and (b) physiological changes of the resistances of the vertebral arteries have been studied. The influence of the posterior perforating arteries on the flow in the posterior communicating arteries has been investigated as well, with special attention being paid to the possible occurrence of a 'dead point'. In the model, the influence of diameters of the communicating arteries on the flow in the afferent vessels and the segments of the circle turns out to be considerable, especially in the range of the anatomical variation of the diameters. Within this range flow reductions due to an increased resistance of the vertebral artery will be compensated for by the system. Assuming that the values and ratios of the peripheral resistances are within the physiological range, a dead point is not to be expected in the flow in the posterior communicating arteries.     

Effect of magnesium ions on heat denaturation of DNA

The dependence of animal DNA denaturation on magnesium ion concentration has been studied in the range (10(-6)--10(-1) M with sodium ion content of 10(-3) and 10(-2) M. Special attention has been given to the effect of multivalent metallic impurities bound to DNA. An increase of DNA thermal stability has been shown to occur in the magnesium concentration rage of 10(-6)--10(-4) M. At concentrations exceeding 10(-3) M the T M begins to decrease. The dependence of the DNA melting range on magnesium ion concentration has a maximum at approximately 10(-5) M Mg2+. At low magnesium and sodium ion concentrations a strong asymmetry of the melting curves has been observed. This effect can be described in terms of the melting theory for DNA complexed with small molecules and is explained by magnesium ion redistribution from the denatured portions of DNA to native ones. The method for calculation of melting curves in the DNA-ligand system has been proposed. Studies of thermal denaturation parameters have been shown to be an effective method for the estimation of binding constants of ligands to native and denatured DNA.     

The frequency dependence of an analytical model of an electrically stimulated biological structure

A digital computer simulation has been carried out of the exposure of a cell, modeled as a multilayered spherical structure, to an alternating electrical field. Electrical and electrochemical quantities of possible biological interest can be evaluated everywhere inside the cell. A strong frequency behavior in the range 0-10 MHz has been obtained.     

Plasmatubules – real modifications of the plasmalemma

Plasmatubules are specific (approximately 20 nm diameter) evaginations of the plasmalemma, found at sites where high solute flux from apoplast to symplast is known, or inferred, to occur for short periods. First described in the distal, endosperm, end of barley scutellar epithelial cells, their structure has subsequently been confirmed using a range of both aqueous and non-aqueous fixation techniques. Plasmatubules have now been described in a range of tissues and species, and examination of published micrographs indicates that this range could be extended further.     

A Species of Tetrahymena Parasitic in the Renal Organ of the Slug Deroceras reticulatum

SUMMARY. A ciliate found in the renal organ of the gray garden slug, Deroceras reticulatum , is referred to Tetrahymena (Paraglaucoma) rostrata (Kahl). In the parasitic phase, the ciliate is evidently not histiophagic. It is readily cultivated in bacterized tissue infusions, and has been established in axenic culture in yeast extract.
The number of complete primary ciliary meridians in ciliates of the parasitic phase has been observed to range from 41 to 58; in ciliates from cultures, the number of meridians has been observed to range from 28 to 37. In culture, the form of T. rostrata from D. reticulatum appears to be morphologically identical with a strain (NZ-4) recovered from soil in New Zealand.     

Application of optical imaging and spectroscopy to radiation biology

Optical imaging and spectroscopy is a diverse field that has been of critical importance in a wide range of areas in radiation research. It is capable of spanning a wide range of spatial and temporal scales, and has the sensitivity and specificity needed for molecular and functional imaging. This review will describe the basic principles of optical imaging and spectroscopy, highlighting a few relevant applications to radiation research.