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.     

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.     

Essential role of follicle stimulating hormone in the maintenance of caprine preantral follicle viability in vitro

The aims of the present study were to investigate the effects of follicle-stimulating hormone (FSH) on survival, activation and growth of caprine primordial follicles using histological and ultrastructural studies. Pieces of caprine ovarian cortex were cultured for 1 or 7 days in minimum essential medium (MEM - control medium) supplemented with different concentrations of FSH (0, 10, 50 or 100 ng/ml). Small fragments from non-cultured ovarian tissue and from those cultured for 1 or 7 days in a specific medium were processed for classical histology and transmission electron microscopy (TEM). Additionally, effects of FSH on oocyte and follicle diameter of cultured follicles were evaluated. The results showed that the lowest percentage of normal follicles was observed after 7 days of culture in control medium. After 1 day of culture, a higher percentage of growing follicles was observed in the medium supplemented with 50 ng/ml of FSH. In the presence of 10 and 50 ng/ml of FSH, an increase in diameter of both oocyte and follicle on day 7 of culture was observed. TEM showed ultrastructural integrity of follicles after 1 day of culture in MEM and after 7 days in MEM plus 50 ng/ml FSH, but did not confirm the integrity of those follicles cultured for 7 days in MEM. In conclusion, this study demonstrated that FSH at concentration of 50 ng/ml not only maintains the morphological integrity of 7 days cultured caprine preantral follicles, but also stimulate the activation of primordial follicles and the growth of activated follicles.     

Expression of follicle-stimulating hormone receptor (FSHR) in goat ovarian follicles and the impact of sequential culture medium on in vitro development of caprine preantral follicles

This study evaluated the expression of FSH receptors (FSHR) in the different stages of goat follicle development and investigated whether the addition of increasing concentrations of FSH throughout the culture period influences the survival, growth and antral formation of in vitro-cultured caprine preantral follicles. The expression of FSHR was analysed before and after culturing follicles using real-time RT-PCR. For the culture, preantral follicles (≥150 μm) were isolated from ovarian fragments and cultured for 18 days in α-MEM+ alone or associated with recombinant FSH (rFSH: 100 or 1000 ng/ml), or in α-MEM+ supplemented with increasing concentrations of FSH throughout culture periods as follows: (a) sequential medium 1: FSH 100 ng/ml (from day 0 to 6), FSH 500 ng/ml (from day 6 to 12) and FSH 1000 ng/ml (from day 12 to 18); and (b) sequential medium 2: FSH 500 ng/ml (from day 0 to 9) and 1000 ng/ml (from day 9 to 18). Follicle development was evaluated on the basis of antral cavity formation, follicular and oocyte growth, and cumulus-oocyte complex health. The expression of FSHR in isolated caprine follicles increased from the preantral to antral phase. Regarding the culture, after 18 days, sequential medium 1 promoted follicular survival, antrum formation and a reduction in oocyte extrusion. Both sequential media promoted a higher rate of meiotic resumption compared with the other treatments. In conclusion, the addition of increased concentrations of FSH (sequential medium) has a significant impact on the in vitro development of caprine preantral follicles.     

Leukemia inhibitory factor stimulates the transition of primordial to primary follicle and supports the goat primordial follicle viability in vitro

The aim of this study was to evaluate the effect of leukemia inhibitory factor (LIF) on the activation and survival of preantral follicles cultured in vitro enclosed in ovarian fragments (in situ). Goat ovarian cortex was divided into fragments to be used in this study. One fragment was immediately fixed (fresh control - FC) and the remaining fragments were cultured in supplemented minimum essential medium (MEM) without (cultured control - CC) or with different concentrations of LIF (1, 10, 50, 100 or 200 ng/ml) for 1 or 7 days, at 39°C in air with 5% CO2. Fresh control, CC and treated ovarian fragments were processed for histological and fluorescence analysis. The percentage of histological normal preantral follicles cultured for 7 days with 1 ng/ml (49.3%), 10 ng/ml (58.6%) and 50 ng/ml (58%) of LIF was higher than in the CC (32.6%; p < 0.05). After 7 days of culture, the percentage of primordial follicles in situ cultured with LIF decreased and primary follicles increased in all LIF concentrations compared with FC and CC (p < 0.05). In conclusion, LIF induced primordial follicle activation and supported preantral follicle viability of goat ovarian tissues cultured for 7 days.     

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.     

The partition matrix: exploring variable phylogenetic signals along nucleotide sequence alignments

The partition matrix is a graphical tool for comparative analysis of nucleotide sequences following alignment. It is particularly useful for investigating the divergent phylogenies of sequence regions undergoing reticulate evolution. A partition matrix is generated by determining the consistency of the parsimoniously informative sites in a set of aligned sequences with the binary partitions inferred from the sequences. Since the linear order of sites is maintained, the matrix can be used to assess whether the distribution of sites either supporting or conflicting with particular partitions changes along the length of the alignment. The usefulness of the matrix in allowing visual identification of differences in evolutionary history among regions depends on the order in which partitions are shown; several suitable ordering schemes are proposed. We demonstrate the use of the partition matrix in interpreting the evolution of the pseudoautosomal boundary region on the sex chromosome of catarrhine primates. Its routine use should help to avoid attempts to derive single phylogenies from sequences whose evolution has been reticulate and to identify the gene conversion or recombination events underlying the reticulation. The method is relatively fast. It is exploratory, and it can form the basis for more formal analysis, which we discuss.      

The Cytoplasmic pH Influences Hyphal Tip Growth and Cytoskeleton-Related Organization

The regulatory role of protons in hyphal tip growth was investigated by using membrane-permeant weak acids to acidify cytoplasm of the oomycete Saprolegnia ferax. Acetic acid decreased cytoplasmic pH from approximately pH 7.2 to 6.8, as shown by SNARF-1 measurements of cytoplasmic pH. Inhibition of growth in a dose-dependent manner by acetic, propionic, and isobutyric acid was accompanied by changes in positioning and morphology of mitochondria and nuclei, condensation of chromatin, disruptions in peripheral actin, and increases in hyphal diameter. These cellular alterations were fully reversible, and during recovery, major cytoplasmic movements and extensive apical vacuolations were observed. The results are consistent with proton regulation of the cytoskeleton, nuclear matrix, and/or chromosomes. However, a macroscopic cytoplasmic gradient of H+ in hyphae was not revealed by SNARF-1, indicating that if such a H+ gradient were required, it must occur at a finer level than we detected.     

3-Methyleneoxindole and Plant Growth Regulation

The campound 3-methyleneoxindole was synthesized and tested in three “biological systems for auxin activity: Root initarion in pea stem currings, extension growth of etiolated pea stem segments and Avena first internodes. In none of the systems was found any effect — positive or negative of methyleneoxindole. It thus seems improbable that the compound participates in the growth regulation of these plants.