X chromosome constitution and the human female phenotype

Summary The correlations of abnormal X chromosome constitutions and the resulting phenotypes in the human female are reviewed. The following hypotheses put forward to explain these correlations are discussed in detail: (1) The damage is done before X inactivation; (2) An effect is exerted between reactivation of the X chromosome(s) and meiosis in oocytes; (3) A recessive gene(s) in hemizygous condition might be expressed in the cases in which the same X is active in all cells; (4) A change in the number of presumed active regions on the inactive X chromosomes might have an effect; (5) A position effect, in that the region Xq13-q27 has to be intact in both X chromosomes to allow normal development, may be responsible; (6) An effect during the period when cells with different inactivation patterns compete is a probability; (7) The original X inactivation may be neither regular nor random.The conclusion reached is that the phenotypic effects of a specific X chromosome aberration may be simultaneously exerted through different pathways (Tables 1 and 2). Hypotheses (2), (4), (5), and (6) are considered probable. Hypothesis (3) has been discarded, and there is very little evidence for hypotheses (1) and (7).     

Spatial patterns in aquatic vegetation composition and environmental covariates along chains of lakes in the Kokemäenjoki watershed (S. Finland)

The diversity and community structure of macrophyte vegetation was studied in 50 boreal lakes forming several upper reaches of lake chains around Lammi, southern Finland. Water chemical parameters and morphometry of the basins were included in a multivariate analysis. Floating-leaved vegetation was the dominant growth form, followed by emergent plants. In downstream lakes, the dominance of floating-leaved macrophytes declined, and emergent species increased in abundance. Species richness was highest in larger lakes, with a wider range of littoral habitats than smaller lakes. Electrical conductivity (range 18–151 mS cm⁻¹, 25 °C) of the water correlated well with patterns in diversity among lakes, but this was not the case for nutrient concentrations. As a whole, morphometrical characteristics of lake basins showed better correlations with vegetation structure than any of the measured chemical parameters. The macrophyte vegetation of neighbouring lake chains differed considerably, depending on the surrounding landscape properties, water quality of the lakes and immigration history of plant species.     

Genetic diversity in strains of the genus Anabaena isolated from planktonic and benthic habitats of the Gulf of Finland (Baltic Sea)

Late summer cyanobacterial blooms in the Baltic Sea contain Anabaena sp. together with Nodularia spumigena and Aphanizomenon flos-aquae. Although Anabaena is common especially in the Gulf of Finland, very little is known about its genetic diversity. Here we undertook a molecular phylogenetic study of 68 Anabaena strains isolated from the brackish Gulf of Finland. We sequenced the 16S rRNA genes from 54 planktonic and 14 benthic Anabaena strains, and rbcL and rpoC1 genes from a subset of these strains. Phylogenetic trees showed that Anabaena strains, from both planktonic and benthic habitats, were genetically diverse. Although the Anabaena strains were morphologically diverse, in our study only one genetically valid species was found to exist in the plankton. Evolutionary distances between benthic Anabaena strains were greater than between planktonic strains, suggesting that benthic habitats allow for the maintenance of greater genetic diversity than planktonic habitats. A number of novel lineages containing only sequences obtained in this study were compiled in the phylogenetical analyses. Thus, it seemed that novel lineages of the genus Anabaena may be present in the Baltic Sea. Our results demonstrate that the Baltic Sea Anabaena strains show surprisingly high genetic diversity.     

Evaluation of different phenol hydroxylase-possessing phenol-degrading pseudomonads by kinetic parameters

Phenol-degrading pseudomonads possessing different phenol hydroxylases (PH) were evaluated by the values of apparent half-saturation constant for phenol-oxygenating activity (K ( S )), maximum specific growth rate (mu (max)), lag-time length (lambda), inhibition constant (K ( I )) and growth yield factor (Y ( X/S )). Strains of the same PH type showed similar kinetic parameters: single-component PH (sPH) harbouring strains had higher values of K ( S ) and lower values of mu (max) than the strains having multicomponent PH (mPH). However, the values of K ( I ) and the dependencies of the lag-time length on initial phenol concentration were strain-specific. The elevated ratio between specific activities of catechol 1,2-dioxygenase (C12O) and muconate cycloisomerase in sPH-strains caused irreversible accumulation of a high amount of exogenous cis,cis-muconate (CCM) which resulted in decreased Y ( X/S ) values. Co-presence of sPH and mPH genes did not give the strains PC16 and P69 any extra advantage and according to determined kinetic parameters only one PH was active during phenol degradation. At the same time simultaneous functioning of catechol ortho and meta cleavage pathways (strain PC20) resulted in higher mu (max) and Y ( X/S ) values. Evaluation of strains showed that the type of PH determined the efficiency of phenol degradation, whereas the tolerance to elevated phenol concentrations was strain-specific.     

The effects of sex, age and breeding success on breeding dispersal of pied flycatchers along a pollution gradient

We modelled breeding dispersal of an insectivorous bird, the pied flycatcher (Ficedula hypoleuca) around a point source of heavy metals (a copper smelter). We tested for the effects of sex, age, breeding success and environmental pollution on breeding dispersal distances of F. hypoleuca females and males. Unlike many earlier studies on breeding dispersal, we took into account distance-dependent sampling bias by including in our model the recapture probabilities at different distances from the site of origin. Our results show that F. hypoleuca females disperse much farther (on average 7.9 km) from their breeding sites than what was previously thought. In contrast, males only disperse short distances (on average 190 m). Breeding success affected female breeding dispersal distances depending on female age: young females moved on average 8 km from their previous breeding place irrespective of their breeding success, while old females only seemed to move this far when their fledgling production was good. Females successful in their breeding dispersed as far as less successful females, or, among old birds, even farther. Females which dispersed long distances produced more fledglings after the movement than those staying near their previous breeding site. Degree of environmental pollution had no effect on female or male breeding dispersal distances. A polluted and unproductive environment does not seem to stimulate F. hypoleuca parents to move to more profitable territories.     

Computer-assisted, high-performance liquid chromatography with mass spectrometric detection for the analysis of coumarins in Peucedanum palustre and Angelica archangelica

A reversed-phase HPLC method with atmospheric pressure chemical ionisation MS detection has been developed for the separation and identification of coumarins in plants of Peucedanum palustre L. (Moench) and Angelica archangelica (L.) var. archangelica. The Turbo Method Development program was utilised to optimise the mobile phase with two organic solvents (acetonitrile and methanol) and two aqueous solutions (1.0% formic acid and 10 mM ammonium acetate). Optimisation of the solvent gradients for the method was performed with the aid of the DryLab program. Analyses were carried out using a Phenomenex Prodigy RP C18 column. Fifty-two peaks (14 of which were associated with coumarins) were separated in 30 min from extracts of P. palustre, and 48 peaks (15 associated with coumarins) from extracts of A. archangelica. A total of 21 different coumarin-type compounds were identified in the aerial and the underground parts of the title plants. Isopimpinellin and pimpinellin were found for the first time in P. palustre and were identified by comparison of retention times and MS data obtained following the analysis of pure standards. This is the first report of the coumarin composition of the umbels of P. palustre.     

Divergent effect of mometasone on human eosinophil and neutrophil apoptosis

Mometasone is a potent synthetic glucocorticoid, which is under development as an inhaled preparation for the treatment of asthma. Previous studies have suggested that glucocorticoids have direct effects on human eosinophil and neutrophil apoptosis. The present study was designed to characterize the effects of mometasone on constitutive apoptosis and cytokine-afforded survival in isolated human eosinophils and neutrophils. The isolated eosinophils or neutrophils were cultured in vitro, and apoptosis was assessed by flow cytometric analysis of relative DNA content, by annexin-V binding and morphological analysis. Mometasone enhanced constitutive human eosinophil apoptosis in a concentration-dependent manner. The maximal enhancement of eosinophil apoptosis was 2.1-fold with an EC(50) value of 5.63 +/- 2.33 nM. This enhancing effect was reversed by the glucocorticoid receptor antagonist, mifepristone. In the presence of added cytokines, mometasone reversed tumor necrosis factor -alpha-induced eosinophil survival but not that afforded by interleukin -5. In contrast, mometasone inhibited human neutrophil apoptosis in a concentration-dependent manner. The maximal inhibition of neutrophil apoptosis was 50% with an EC(50) value of 0.17 +/- 0.03 nM. The inhibitory effect was partly reversed by mifepristone. In the presence of added cytokines, mometasone further enhanced neutrophil survival induced by the granulocyte-macrophage colony-stimulating factor and leukotriene B(4). The present data suggests that mometasone has opposite effects on apoptosis of human eosinophils and neutrophils at clinically relevant drug concentrations via an effect on glucocorticoid receptor.     

The Effects of Increasing UV-B Radiation on Pigmentation, Growth and Survival of Coregonid Embryos and Larvae

In the northern regions UV-B radiation levels have increased due to ozone depletion. A two-week laboratory experiment was conducted to measure the effects of UV-B radiation on the pigmentation, growth, oxygen consumption rate and survival of whitefish, Coregonus lavaretus, and vendace, Coregonus albula, larvae. In May newly hatched embryos were exposed in laboratory aquaria to three CIE weighted UV-B radiation levels: subambient (daily dose 1.37kJm^–2), 9% (1.81kJm^–2) and 34% higher (2.24kJm^–2) than ambient. Control embryos and larvae were not exposed to UV-B. Larvae of whitefish and vendace that were irradiated with highest UV-B level had 32% and 31% more melanin than control larvae, respectively, which we interpret as an apparent induced response. In controls, the species difference revealed 53% more melanin in vendace larvae than in whitefish larvae. UV-B radiation had no effect on the mortality of either species, the survival being high in all treatments (>90%). Additionally, neither growth rate nor the metabolic rate of larvae of either species was affected by UV-B radiation. Thus, in relation to future scenarios UV-B radiation may not be a threat to whitefish or vendace larvae in current or expected radiation levels.     

A beta-helical antifreeze protein isoform with increased activity. Structural and functional insights

The insect spruce budworm (Choristoneura fumiferana)(Cf) produces a number of isoforms of its highly active antifreeze protein (CfAFP). Although most of the CfAFP isoforms are in the 9-kDa range, isoforms containing a 30- or 31-amino acid insertion have also been identified. Here we describe the functional and structural analysis of a selected long isoform, CfAFP-501. X-ray crystal structure determination reveals that the 31-amino acid insertion found in CfAFP-501 forms two additional loops within its highly regular beta-helical structure. This effectively extends the area of the two-dimensional Thr array and ice-binding surface of the protein. The larger isoform has 3 times the thermal hysteresis activity of the 9-kDa CfAFP-337. As well, a deletion of the 31-amino acid insertion within CfAFP-501 to form CfAFP-501-Delta-2-loop, results in a protein with reduced activity similar to the shorter CfAFP isoforms. Thus, the enhanced antifreeze activity of CfAFP-501 is directly correlated to the length of its beta-helical structure and hence the size of its ice-binding face.