A biometric study of some hybridizing Crataegus populations in Denmark

Crataegus curvisepala Lindm., C. laevigata (Poiret) DC. and C. monogyna Jacq. (Rosaceae) form hybrid complexes in Denmark due to introgression. C. palmstruchii Lindm. seems to be variously introgressed individuals of C. laevigata. C. eremitagensis Raunk., C. raavadensis Raunk. and C. schumacheri Raunk. apparently belong to C. curvisepala x laevigata. The delimitation between C. curvisepala x laevigata and C. laevigata x monogyna is discussed.     

Spore probiotics

Data on probiotic preparations prepared from spore-forming bacteria is reviewed. Information on indications for use, effectiveness and the mechanism of action is given. Preparations being produced in Russia (Biosporin, Sporobacterin and Bactosporin) are evaluated in detail as well as the prospects of the application of probiotics from spore-forming bacteria.     

On the history of nuclear matrix manifestation

The nonchromatin proteinous residue of the cell nucleus was revealed in our laboratory as early as in 1948 and then identified by light and electron microscopy as residual nucleoli,intranuclear network and nuclear envelope before 1960,This structure termed afterwards as “nuclear residue“,“nuclear skeleton“,“nuclear cage“,“nuclear carcass“etc.,was much later(in 1974) isolated,studied and entitled as “nuclear matrix“ by Berezney and Coffey,to whom the discovery of this residual structure is often wronly ascribed.The real history of nuclear matrix manifestation is reported in this paper.     

Does urbanization affect selective pressures and life‐history strategies in the common blackbird (Turdus merula L.)?

Urbanization, one of the most extreme land‐use alterations, is currently spreading, and the number of species confronting these changes is increasing. However, contradictory results of previous studies impede a clear interpretation of which selective pressure (nest predation or food limitation) is more important in urban habitats compared with natural situations, and whether birds can confront them by adjusting their life‐history strategies. We investigated life‐history syndromes of three common blackbird (Turdus merula) populations differing in their human influence (urban, rural, and woodland). We analysed daily nest predation and nestling starvation rates to assess the relative importance of these selection pressures in each habitat. Simultaneously, several life‐history traits were investigated to determine if T. merula seem adapted to their main source of selection. Food limitation was more important in the city, whereas nest predation was the most important selective force in the forest. The rural habitat was characterized by an intermediate influence of these two factors. Life‐history syndromes, as the covariation of a suite of traits, confirmed these results because T. merula seem well adapted to the main cause of selection in each habitat. Our results are consistent with urbanization imposing new challenges on birds, and that they adaptively respond to them. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 759–766.     

New producers of site-specific endonucleases from microorganisms of the Bacillus genus

52 strains of Bacillus generum have been tested for production of site-specific endonucleases. The sequence recognized by the enzyme was determined for 23 enzymes, the cleavage site inside the sequence was determined for 5 enzymes. All the enzymes under study were found to be isomers of the known enzymes. The selected strains are peculiar for the high level of site-specific endonucleases content and may be used as producents of the enzymes.     

Affinity-selected filamentous bacteriophage as a probe for acoustic wave biodetectors of Salmonella typhimurium

Proof-in-concept biosensors were prepared for the rapid detection of Salmonella typhimurium in solution, based on affinity-selected filamentous phage prepared as probes physically adsorbed to piezoelectric transducers. Quantitative deposition studies indicated that approximately 3 x 10(10)phage particles/cm(2) could be irreversibly adsorbed for 1 h at room temperature to prepare working biosensors. The quality of phage deposition was monitored by fluorescent microscopy. Specific-bacterial binding resulted in resonance frequency changes of prepared sensors, which were evaluated using linear regression analysis. Sensors possessed a rapid response time of <180 s, had a low-detection limit of 10(2)cells/ml and were linear over a range of 10(1)-10(7)cells/ml with a sensitivity of 10.9 Hz per order of magnitude of S. typhimurium concentration. Viscosity effects due to increasing bacterial concentration and non-specific binding were not significant to the piezoelectric platform as confirmed by dose-response analysis. Phage-bacterial binding was confirmed by fluorescence and scanning electron microscopy. Overall, phage may constitute effective bioreceptors for use with analytical platforms for detecting and monitoring bacterial agents, including use in food products and possibly biological warfare applications.     

Quantification of the magnification and distortion effects of a pediatric flexible video-bronchoscope

Background

Flexible video bronchoscopes, in particular the Olympus BF Type 3C160, are commonly used in pediatric respiratory medicine. There is no data on the magnification and distortion effects of these bronchoscopes yet important clinical decisions are made from the images. The aim of this study was to systematically describe the magnification and distortion of flexible bronchoscope images taken at various distances from the object.

Methods

Using images of known objects and processing these by digital video and computer programs both magnification and distortion scales were derived.

Results

Magnification changes as a linear function between 100 mm (×1) and 10 mm (×9.55) and then as an exponential function between 10 mm and 3 mm (×40) from the object. Magnification depends on the axis of orientation of the object to the optic axis or geometrical axis of the bronchoscope. Magnification also varies across the field of view with the central magnification being 39% greater than at the periphery of the field of view at 15 mm from the object. However, in the paediatric situation the diameter of the orifices is usually less than 10 mm and thus this limits the exposure to these peripheral limits of magnification reduction. Intraclass correlations for measurements and repeatability studies between instruments are very high, r = 0.96. Distortion occurs as both barrel and geometric types but both types are heterogeneous across the field of view. Distortion of geometric type ranges up to 30% at 3 mm from the object but may be as low as 5% depending on the position of the object in relation to the optic axis.

Conclusion

We conclude that the optimal working distance range is between 40 and 10 mm from the object. However the clinician should be cognisant of both variations in magnification and distortion in clinical judgements.     

Phage as a molecular recognition element in biosensors immobilized by physical adsorption

Biosensors based on landscape phages immobilized by physical adsorption on the surface of a quartz crystal microbalance was used for detection of beta-galactosidase from Escherichia coli. The sensor had a detection limit of a few nanomoles and a response time of a approximately 100 s over the range of 0.003-210 nM. The binding dose-response curve had a typical sigmoid shape and the signal was saturated at the beta-galactosidase concentration of about 200 nM. A marked selectivity for beta-galactosidase over BSA was observed in mixed solutions even when the concentration of BSA exceeded the concentration of beta-galactosidase by a factor of approximately 2000. The apparent value of the dissociation constant (K(d)) of the interaction of free phage with beta-galactosidase (9.1+/-0.9 pM) was smaller compared with the one calculated for the bound phage (1.7+/-0.5 nM). The binding was specific with three binding sites needed to bind a single molecule of beta-galactosidase. The K(d) obtained from the enzyme-linked immunosorbent assay (ELISA) for the phage and the monoclonal anti-beta-galactosidase antibodies were 21+/-2 and 26+/-2 nM, respectively. Although the method of physical adsorption is simpler and more economical in comparison with Langmuir-Blodgett and molecular assembling methods the performances of the sensors made by these technologies compare well. This work provides evidence that phage can be used as a recognition element in biosensors using physical adsorption method for immobilization of phage on the sensor surface.