No evidence of contemporary interploidy gene flow between the closely related European woodland violets Viola reichenbachiana and V. riviniana (sect. Viola, Violaceae).

Viola reichenbachiana (2n = 4x = 20) and V. riviniana (2n = 8x = 40) are closely related species widely distributed in Europe, often sharing the same habitat throughout their overlapping ranges. It has been suggested in numerous studies that their high intraspecific morphological variability and plasticity might have been further increased by interspecific hybridisation in contact zones, given the sympatry of the species and the incomplete sterility of their hybrid. The aims of this study were to: (i) confirm that V. reichenbachiana and V. riviniana have one 4x genome in common, and (ii) determine the impact of hybridisation and introgression on genetic variation of these two species in selected European populations. For our study, we used 31 Viola populations from four European countries, which were analysed using AFLP and sequencing of a variable plastid intergenic spacer, trnH-psbA. Our analysis revealed that V. reichenbachiana exhibited larger haplotype diversity, having three species-specific haplotypes versus one in V. riviniana. The relationships among haplotypes suggest transfer of common haplotypes into V. riviniana from both V. reichenbachiana and hypothetically the other, now extinct, parental species. AFLP analysis showed low overall genetic diversity of both species, with V. riviniana showing higher among-population diversity. None of the morphologically designated hybrid populations had additive AFLP polymorphisms that would have indicated recent hybridisation. Also, kinship coefficients between both species did not indicate gene flow. V. riviniana showed significant population subdivision and significant isolation by distance, in contrast to V. reichenbachiana. The results indicate lack of gene flow between species, high influence of selfing on genetic variability, as well as probably only localised introgression toward V. riviniana.

Morphological versus genetic diversity of Viola reichenbachiana and V. riviniana (sect. Viola, Violaceae) from soils differing in heavy metal content.

Morphological characters, AFLP markers and flow cytometry were used to investigate the morphological and genetic variability and differentiation of Viola reichenbachiana and V. riviniana in non-metallicolous (NM) and metallicolous (M) populations. The aims were to clarify the taxonomic status of plants occurring in ore-bearing areas, to determine any relationship in V. reichenbachiana and V. riviniana from sites not polluted with heavy metals, and to examine the genetic variability and differentiation of M and NM populations of both species. Multivariate analyses based on morphological characters showed significant differences between V. reichenbachiana and V. riviniana from non-polluted sites, high levels of intra- and inter-population variability, and the occurrence of inter-specific hybrids. Plants from M populations showed hybrid characters but also fell within the range of V. riviniana or V. reichenbachiana. There were no significant differences in relative genome size between plants from polluted areas and V. riviniana from NM populations. Bayesian analysis of population genetic structure based on AFLP markers distinguished two main groups: V. reichenbachiana and V. riviniana together with the M populations. That analysis also revealed the occurrence of populations of inter-specific hybrids from non-polluted areas. Further Bayesian analysis of V. riviniana including NM and M populations separated all the studied M populations from NM populations. We conclude that plants forming the M populations are well adapted to a metal-polluted environment, and could be considered as stabilised introgressive forms resulting from unidirectional (asymmetric) introgression toward V. riviniana.

Increased genetic diversity of Viola tricolor L. (Violaceae) in metal-polluted environments.

Changes in DNA sequences affecting cryptic intraspecific variability are very important mechanisms of plant microevolutionary processes, initiating species diversification. In polluted environments, intra- and interpopulation changes at the molecular level proceed rapidly and lead to the formation of new ecotypes in a relatively short time. We used ISSR PCR fingerprinting data to analyze the genetic diversity and genetic structure of seven populations of Viola tricolor: four growing on soil contaminated with heavy metals (Zn, Pb, Cd; waste heaps) and three from control soil. The populations from the polluted sites showed higher genetic polymorphism (%(poly)=84%) and gene diversity (H(T)=0.1709) than the control populations (%(poly)=75% and H(T)=0.1448). The number of private markers we detected within metallicolous (MET) populations was more than double that found within non-metallicolous (NON) populations (15 vs. 7). The STRUCTURE and UPGMA analyses showed clear genetic differences between the NON and MET populations. Based on broad analyses of the genetic parameters, we conclude that the effect of these polluted environments on the genetic diversity of the MET populations, separating them from the NON populations, is evidence of microevolutionary processes at species level, leading to species divergence and the emergence of local ecotypes better adapted to their different environments.

A contribution to characterisation of genetic variation in some natural Polish populations of Elymus repens (L.) Gould and Elymus hispidus (Opiz) Melderis (Poaceae) as revealed by RAPD markers.

To determine the relative importance of clonal growth and sexual reproduction, the Randomly Amplified Polymorphic DNA (RAPD) method was used to study genetic diversity and clonal structure of six populations of Elymus repens and four populations of Elymus hispidus from Poland. These outbreeding species are virtually self-sterile and form widely spreading and long-lived rhizomes. Using 12 primers, a total of 150 unambiguous RAPD fragments were amplified and scored. Results of AMOVA showed no significant genetic distinction between morphologically distinguished varieties of E. repens and E. hispidus. E. repens had slightly higher intra-specific genetic polymorphism than E. hispidus; the percentage of polymorphic bands per population ranged from 38 to 49 and from 19 to 38 respectively. Clonal diversity measured using the Simpson diversity index (D) indicated different contributions of clonal reproduction in particular populations of E. repens (D: 0.20-0.72). Populations of E. hispidus were dominated by one or a few clones, which were generally restricted to a single population (D: 0.00-0.22). RAPD revealed that most genetic diversity resided within populations of the two studied species, suggesting that, despite their clonal character, propagation by seeds contributes considerably to reproduction of E. repens and E. hispidus.

Charge separation, stabilization, and protein relaxation in photosystem II core particles with closed reaction center.

The fluorescence kinetics of cyanobacterial photosystem II (PSII) core particles with closed reaction centers (RCs) were studied with picosecond resolution. The data are modeled in terms of electron transfer (ET) and associated protein conformational relaxation processes, resolving four different radical pair (RP) states. The target analyses reveal the importance of protein relaxation steps in the ET chain for the functioning of PSII. We also tested previously published data on cyanobacterial PSII with open RCs using models that involved protein relaxation steps as suggested by our data on closed RCs. The rationale for this reanalysis is that at least one short-lived component could not be described in the previous simpler models. This new analysis supports the involvement of a protein relaxation step for open RCs as well. In this model the rate of ET from reduced pheophytin to the primary quinone Q(A) is determined to be 4.1 ns(-1). The rate of initial charge separation is slowed down substantially from approximately 170 ns(-1) in PSII with open RCs to 56 ns(-1) upon reduction of Q(A). However, the free-energy drop of the first RP is not changed substantially between the two RC redox states. The currently assumed mechanistic model, assuming the same early RP intermediates in both states of RC, is inconsistent with the presented energetics of the RPs. Additionally, a comparison between PSII with closed RCs in isolated cores and in intact cells reveals slightly different relaxation kinetics, with a approximately 3.7 ns component present only in isolated cores.

Charge separation kinetics in intact photosystem II core particles is trap-limited. A picosecond fluorescence study.

The fluorescence kinetics in intact photosystem II core particles from the cyanobacterium Thermosynechococcus elongatus have been measured with picosecond resolution at room temperature in open reaction centers. At least two new lifetime components of approximately 2 and 9 ps have been resolved in the kinetics by global analysis in addition to several known longer-lived components (from 42 ps to approximately 2 ns). Kinetic compartment modeling yields a kinetic description in full agreement with the one found recently by femtosecond transient absorption spectroscopy [Holzwarth et al. (2005) submitted to Proc. Natl. Acad. Sci. U.S.A.]. We have for the first time resolved directly the fluorescence spectrum and the kinetics of the equilibrated excited reaction center in intact photosystem II and have found two early radical pairs before the electron is transferred to the quinone Q(A). The apparent lifetime for primary charge separation is 7 ps, that is, by a factor of 8-12 faster than assumed on the basis of earlier analyses. The main component of excited-state decay is 42 ps. The effective primary charge separation rate constant is 170 ns(-)(1), and the secondary electron-transfer rate constant is 112 ns(-)(1). Both electron-transfer steps are reversible. Electron transfer from pheophytin to Q(A) occurs with an apparent overall lifetime of 350 ps. The energy equilibration between the CP43/CP47 antenna and the reaction center occurs with a main apparent lifetime of approximately 1.5 ps and a minor 10 ps lifetime component. Analysis of the overall trapping kinetics based on the theory of energy migration and trapping on lattices shows that the charge separation kinetics in photosystem II is extremely trap-limited and not diffusion-to-the-trap-limited as claimed in several recent papers. These findings support the validity of the assumptions made in deriving the earlier exciton radical pair equilibrium model [Schatz, G. H., Brock, H., and Holzwarth, A. R. (1988) Biophys. J. 54, 397-405].

Training the next generation of informaticians: the impact of "BISTI" and bioinformatics--a report from the American College of Medical Informatics.

In 2002-2003, the American College of Medical Informatics (ACMI) undertook a study of the future of informatics training. This project capitalized on the rapidly expanding interest in the role of computation in basic biological research, well characterized in the National Institutes of Health (NIH) Biomedical Information Science and Technology Initiative (BISTI) report. The defining activity of the project was the three-day 2002 Annual Symposium of the College. A committee, comprised of the authors of this report, subsequently carried out activities, including interviews with a broader informatics and biological sciences constituency, collation and categorization of observations, and generation of recommendations. The committee viewed biomedical informatics as an interdisciplinary field, combining basic informational and computational sciences with application domains, including health care, biological research, and education. Consequently, effective training in informatics, viewed from a national perspective, should encompass four key elements: (1). curricula that integrate experiences in the computational sciences and application domains rather than just concatenating them; (2). diversity among trainees, with individualized, interdisciplinary cross-training allowing each trainee to develop key competencies that he or she does not initially possess; (3). direct immersion in research and development activities; and (4). exposure across the wide range of basic informational and computational sciences. Informatics training programs that implement these features, irrespective of their funding sources, will meet and exceed the challenges raised by the BISTI report, and optimally prepare their trainees for careers in a field that continues to evolve.

[Apolipoprotein E(ApoE)and tau protein in Alzheimer type dementia]. / Apolipoproteina (ApoE) i bialko tau w otepieniu typu Alzheimera.

In 45 patients meeting NINCDS-ARDRA criteria for probably diagnosis of Alzheimer disease (AD), ApoE genotype and tau protein level in cerebro-spinal fluid (CSF) were determined. Frequency of e4 allele occurrence in group of AD patients was 73.3% and showed high statistic significance in comparison with control group. Increase of tau protein level in CSF was also statistically significant. No correlation in ApoE allele and tau protein level in CSF was revealed. The authors emphasize the usefulness of tau protein level measurement and determination of ApoE allele in diagnosis of Alzheimer disease.

Fundamental differences of excitation spectrum between malignant and benign breast tissues.

Differences observed in the UV excitation spectrum of malignant and benign breast tissues are used to distinguish between malignant and benign breast tissues. These changes are attributed to changes with specialized proteins.

Secretin, cholecystokinin and the biliary canalicular secretion in the rat.

An attempt has been made to further assess which fraction of bile can be stimulated by the main gastrointestinal hormones in rats. In the cannulated conscious animals the i.v. infusions of glucagon, impure Boots secretin, impure Boots cholecystokinin (CCK) and OP-CCK resulted in 8.9% (N.S.), 68.5% (P < 0.001), 88.7% (P < 0.001) and 19.0% (P < 0.05) increase in the estimated bile acid-dependent bile flow (BAF) and in 25.4% (P < 0.01), 49.2% (P < 0.001), 44.5% (P < 0.001) and 1.6% (N.S.) increase in the estimated bile acid-independent bile flow (BAIF), respectively as compared to the control values. When the calculated BAF values corresponding to the bile acid impurities in Boots secretin and Boots CCK were subtracted from BAF and BAIF values obtained during hormone infusions (the corrected values), the increase in both BAF and BAIF was equal to 38.9% (P < 0.02) and 29.4% (P < 0.02) during Boots secretin infusion and to 61.1% (P < 0.01) and 29.4% (P < 0.02) during Boots CCK infusion, respectively as compared to the control values. It can be suggested that the hormonal impurities in the Boots preparations interacting with the principal hormonal component are able to stimulate BAF in the rat. Further extensive study embracing the interactions of the purified gut hormones may confirm their role in the control of canalicular bile secretion in the rat.

[Studies of structure-determined biological aggressiveness of chrysotile asbestos. I. Model of chrysotile crystalline structure]. / Badanie strukturalnych uwarunkowan biologicznej agresywnosci azbestu chryzotylowego. I. Model struktury krystalicznej chryzotylu.

Chrysotile is built out of two kinds of layers placed alternately, namely tridymite (silico-oxygenic) and brucite. A tridymite layer is composed of silico-oxygenic tetrahedrons laid planary in the pseudohexagonal order, while magnesium ions coordinated octahedrally in hydroxyl groups produce a brucite layer. Two layers are bound in a chrysotile molecule through substitution of a part of hydroxine groups of the basis of the brucite layer by oxygen ions from the vertex of the tridymite layer tetrahendrons. The size of an elementary chrysotile cell is as follows: a = 5.3A, b = 9.2A, c = 7.3A, beta = 93 Positions (x, y, z) of all atoms in the elementary chrysotile cell were calculated. In calculations hydrogen atoms were neglected because of small atomic dissipation factor (contribution to the structure) and difficulties in their precise location in the elementary cell. The elementary chrysotile cell is composed of two molecules Mg3 [Si2O5] (OH)4. Crystallographic axes of chrysotile structure were directed in relation to the fibre axis. The values of the elementary chrysotile fibre radii are as follows: R = 208A (starting value) and r = 18.2A (minimum value) A theoretic chrysotile pulverulent diffraction pattern was calculated and drawn. The theoretical pulverulent diffraction pattern of chrysotile was compared with chrysotile diffraction pattern in the card JC PDS21-543. A great similarity between the two diffraction patterns was found.

[Microscopic quality control--numeric representation of asbestos fiber concentration in environmental air of the workplace]. / Kontrola jakosci mikroskopowo--liczbowych oznaczen steenia respirabilnych wlókien azbestu w powietrzu srodowiska pracy.

The study aimed at assessing the reliability of determinations of respirable asbestos fibre concentration which were performed by selected laboratories of the Work Hygiene Departments of the Regional Sanitary Epidemiological Stations (RSES). Two rounds of microscopic specimen exchanges were organized, the specimens containing from 20 to 700 asbestos fibres per 1 mm2. The results of specimen density determinations performed by RSES analysts were compared with reference determinations (i.e. average density determinations performed by 7 workers of the Institute of Occupational Medicine, Lodz, checked by two international tests). During the first exchange, the RSES determinations were found to be significantly lower than the reference determinations. At the second exchange, they exceeded the reference values. The poor precision of determining asbestos fibre concentration by the majority of the RSES analysts makes it necessary to provide additional training for that group, apart from that a survey of the quality of RSES laboratory equipment should be carried out and a system of internal quality control for the RSES laboratories should be developed and implemented.

[International control of the quality of microscopic-numerical analysis of the levels of man-made mineral fibers (MMMF) in the air of the work area]. / Miedzynarodowa kontrola jakosci mikroskopowo-liczbowych analiz oznaczania stezenia sztucznych wlókien mineralnych (MMMF) w powietrzu srodowiska pracy.

In the years 1986-1990 the Institute of Occupational Medicine in Lodz (Department of Aerosols) participated in seven exchanges of preparations within the WHO/Euro MMMF Reference Scheme programme. The number of persons analysing the preparations increased from three, during the first exchange, to seven in the sixth. Markings in the 1st and 3rd exchange constituted two thirds of the reference markings. In the 2nd, 5th and 7th exchange the markings were similar, and in the 6th exchange they were lower than in the reference markings. According to the accepted system, the markings of the standardized density in four exchanges (2nd, 5th, 6th and 7th) were determined as class I (0.70-1.40), and in the remaining exchanges (1st, 3rd and 4th) of class II (0.50-2.00).

[Asbestos substitutes and their biological effects. 2. Synthetic amphiboles--their physico-chemical characteristics]. / Zamienniki azbestu i ich dzialanie biologiczne. 2. Amfibole syntetyczne--charakterystyka fizyczno-chemiczna.

Metal content in the chemical structure of asbestos and man-made mineral fibres can affect their carcinogenic properties. As the chemical composition (metal content) of man-made silicate substitutes for asbestos can be varied almost at will in the process of their manufacture, the search for potentially least carcinogenic silicates appears to be of utmost importance. This paper presents diffractometric characteristics, dimensional analysis and morphology data for 4 synthetic amphibole fibres with chemical compositions differing from that of natural crocidolite amphibole. Those included the following synthetic amphiboles: Na2Mg6Ge8O22(OH)2; Na2Ni6Si8O22(OH)2; Na2Mg6Si8O22(OH)2; Na2Co6Si8O22(OH)2. The studied amphiboles differed in fibre length and diameter. The magnesium amphibole contained the longest (6.03 microns) fibres, and the nickel amphibole contained the shortest (2.7 microns) fibres, resembling those of crocidolite. The highest content (54.7%) of respirable fibres was found in the magnesium amphibole, and the lowest (15.9%) in the natural crocidolite. The authors suggest that the detected differences in the physical and chemical characteristics of the synthetic amphiboles may affect their biological properties.

[Occupational exposure to asbestos-containing dust at the plants manufacturing and using asbestos products during the years 1986-1989]. / Ekspozycja zawodowa na pyly zawierajace azbest w zakladach produkujacych i stosujacych wyroby azbestowe w latach 1986-1989.

During 1986-1989, dust levels at workplaces in 19 plants manufacturing or using asbestos products in Poland were measured. Total dust concentrations were determined by the gravimetric method and respirable asbestos fibre concentrations were determined by the phase contrast optical microscope method (PCOM). Air was sampled at the breathing zones of the workers by using Casella personal air samplers. Average respirable asbestos fibre concentrations at the workplaces were from 0.06 fibre/cm3 (control desk operator) to 2.25 fibre/cm3 (spinning machine operator), and the average total dust concentrations were from 0.7 mg/m3 (technicians) to 2.3 mg/m3 (preparatory department workers). Compared with the 1980-1985 period, total dust concentrations were 1.5 times, and respirable asbestos fibre concentrations 2.9 times lower. Considering the obtained data and the analysis of the occupational diseases in workers exposed to asbestos dust during 1983-1988, the national expert group for industrial dusts has suggested that the MAC values for chrysotile dusts be lowered to 1.0 mg/m3 (total dust) and 0.5 fibre/cm3 (respirable fibre).