Habitat requirements, short-term population dynamics and coexistence of native and invasive Impatiens species: a field study

The genus Impatiens (Balsaminaceae) includes three widespread species in the Czech Republic, central Europe: the native I. noli-tangere, and two invasive species, I. parviflora and I. glandulifera, differing in the dynamics of invasion. They all occur in similar habitats and share basic life-history characteristics, which make them a suitable model for studying species traits associated with invasiveness. In this study we investigated differences in habitat requirements of these Impatiens species, their coexistence and short-term population dynamics in the field. We established 84 1 × 1 m permanent plots in five localities where all three species co-occurred. In each plot vascular plant species were determined, their cover estimated and all individuals of Impatiens species counted. Site characteristics including tree canopy cover, soil moisture, nitrogen and carbon content, and slope were measured directly. Nutrients, light, humidity and soil reaction were estimated using Ellenberg indicator values. The presence of I. noli-tangere was strongly correlated with high soil moisture, that of I. parviflora with high tree canopy cover and low soil moisture. Impatiens glandulifera exhibited a unimodal response to tree canopy cover, avoiding both very shaded and fully open sites. The current-year abundances of all species were negatively related to those of congeneric species. These results suggest that the coexistence of Impatiens species in the same habitat is due to microsite differentiation. Further spread of I. glandulifera to new habitats, and reduction of the native I. noli-tangere niche, can be expected in areas where the latter species co-occurs with competitively strong invasive congeners.     

Phase transitions and antiferromagnetism in copper(II) hexanoates: a new tetranuclear type of copper carboxylate paddle-wheel association

A series of compounds of formula [{Cu₂(OOCC_mH_2m + 1)₄(urea)}₂] (m=5-11) have been characterized. X-ray structure analysis for the hexanoate compound reveals a new type of tetranuclear dicopper(II) tetracarboxylate, where the central coordination sphere in [{Cu₂(OOCC₅H₁₁)₄(urea)}₂] is composed of two dinuclear dicopper tetracarboxylates, connected via two inter-dinuclear Cu-O coordination bonds at a distance 2.222(2) Å through the apical positions of two dimers. Urea molecules (Cu-O 2.114(2) Å) occupy both outside apical positions of the resulting tetranuclear units. A strong antiferromagnetic behaviour has been shown for [{Cu₂(OOCC₅H₁₁)₄(urea)}₂] (−2J=261.4(4) cm⁻¹), and compared with related isolated dinuclear and polymeric hexanoate compounds [Cu₂(OOCC₅H₁₁)₄(urea)₂], [Cu₂(OOCC₅H₁₁)₄]_n, respectively. Only small differences in the magnetic susceptibility have been found, while EPR spectroscopy showed significantly different results for all three hexanoate compounds, also with the dicopper tetracarboxylate central core and square-pyramidal CuO₄O chromophores. A solid-to-solid phase transition for [{Cu₂(OOCC₅H₁₁)₄(urea)}₂] was observed by magnetic measurement and analysed for the whole series [{Cu₂(OOCC_mH_2m + 1)₄(urea)}₂] by TG, DTA, and variable temperature XRD studies.     

On the relationship between the non-photochemical quenching of the chlorophyll fluorescence and the Photosystem II light harvesting efficiency. A repetitive flash fluorescence induction study

Plants respond to excess light by a photoprotective reduction of the light harvesting efficiency. The notion that the non-photochemical quenching of chlorophyll fluorescence can be reliably used as an indicator of the photoprotection is put to a test here. The technique of the repetitive flash fluorescence induction is employed to measure in parallel the non-photochemical quenching of the maximum fluorescence and the functional cross-section (sigma(PS II)) which is a product of the photosystem II optical cross-section a(PS II) and of its photochemical yield Phi(PS II) (sigma (PS II) = a(PS II) Phi(PS II)). The quenching is measured for both, the maximum fluorescence found in a single-turnover flash (F(M) (ST)) and in a multiple turnover light pulse (F(M) (MT)). The experiment with the diatom Phaeodactylum tricornutum confirmed that, in line with the prevalent model, the PS II functional cross-section sigma (PS II) is reduced in high light and restored in the dark with kinetics and amplitude that are closely matching the changes of the F(M) (ST) and F(M) (MT) quenching. In contrast, a poor correlation between the light-induced changes in the PS II functional cross-section sigma (PS II) and the quenching of the multiple-turnover F(M) (MT) fluorescence was found in the green alga Scenedesmus quadricauda. The non-photochemical quenching in Scenedesmus quadricauda was further investigated using series of single-turnover flashes given with different frequencies. Several mechanisms that modulate the fluorescence emission in parallel to the Q(A) redox state and to the membrane energization were resolved and classified in relation to the light harvesting capacity of Photosystem II.     

Chromosome counts and chromosome morphology of some selected species

In the years 1976–1981 we studied chromosome counts and karyotypic formulae of the following 29 species of plants from 41 localities (of these 6 from Bohemia, 32 from Moravia, 3 from Slovakia):Batrachium baudotii (Godron) F. W. Schultz,Chenopodium rubrum L.,C. polyspermum L.,C. murale L.,C. ficifolium Sm.,C. opulifolium Schrader ex DC. inLam. et DC.,C. strictum Roth [subsp.strictum, subsp.glaucophyllum (Aellen)Aellen inJust etAellen, subsp.striatiforme Uotila],Arenaria grandiflora L.,Illecebrum verticillatum L.,Spergula morisonii Boreau inDuchartre,Spergularia marginata (DC. inLam. et DC.)Kittel S. marina (L.)Griseb.,S. rubra (L.) J. etC. Presl,Silene conica L.,Sisymbrium loeselii L.,S. volgense Bieb. exE. Fourn.,S. orientale L. [subsp. orientale, subsp.macroloma (A. Pomel)Dvo?ák],S. officinale (L.)Scop.,Descurainia sophia (L.)Webb exPrantl inEngler etPrantl,Nasturtium officinale R. Br. inAiton,Barbarea arcuata (Opiz inPresl J. et C.)Reichenb.,Lunaria annua L.,Soldanella montana Willd.,S. carpatica Vierh. inUrban etGraebner,Lotus tenuis Waldst. etKit. exWilld.,L. uliginosus Schkuhr,Trigonella monspeliaca L.,Geranium sibiricum L.,Lactuca tatarica (L.)C. A. Meyer.     

Use of algae in the study of essential cell processes

Maintenance of genomic stability is of crucial importance for all living organisms. It is no surprise that during evolution, a series of highly selective and efficient systems to detect DNA damage and control its repair have evolved. To this end, signal transduction pathways are involved in pausing the cell division cycle to provide time for repair, and ultimately releasing the cell cycle from arrest. Genetic components of the damage and replication checkpoints have been identified and a working model is beginning to emerge. This area of biological inquiry has received a great deal of attention in the past decade with the realization that the underlying regulatory mechanisms controlling the cell cycle are conserved throughout eukaryotic evolution. Many of the key players in this response have structural and functional counterparts in species as diverse as yeast and human. In recent years attention has also been paid to the plant kingdom suggesting that checkpoint controls have been highly conserved during evolution. The unicellular green alga Chlamydomonas reinhardtii is a suitable model organism for the study of basic cellular processes including cell cycle regulation and DNA repair. To investigate how algal cells accomplish these tasks, we have isolated mutants in the recognition and repair of DNA damage or in the response to DNA damage. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.     

Diversity of cyanobacteria and algae of urban gravel pit lakes in Bratislava,Slovakia: a survey

Hydrobiologia - This paper presents data on the diversity of cyanobacteria and algae of nine gravel pit lakes situated within the city boundaries of Bratislava, W Slovakia. During more than 30...     

Deletion ΔF508 and haplotype analysis of CFTR gene region in Slovak CF patients

Summary Analysis of a sample of 50 unrelated cystic fibrosis (CF) patients and 46 nuclear families from Slovakia (Czechoslovakia) by the polymerase chain reaction and Southern hybridization revealed that the proportion of the F508 mutation was 58% in this population, and that the frequency of the B (i.e., KM19/XV2c [1–2]) haplotype was increased in both F508 and nonF508 CF chromosomes (98% and 46%, respectively). These results support the view that the trans-European gradient of the F508 frequency is of a geographical rather than of an ethnic origin, and that in Slavonic populations, there exists an as yet unidentified but frequent CF mutation other than F508, associated with the B haplotype.     

Effect of alanyl-glutamine on leucine and protein metabolism in irradiated rats

Summary. The mechanism by which glutamine produces a favorable effect in the treatment of sepsis, injury, burns and abdominal irradiation is not completely understood. The main aim of this study was to evaluate the effect of alanyl-glutamine (AlaGln) administration on the metabolism of proteins in irradiated rats. The rats were exposed to whole-body irradiation (8 Gy) and then fed intragastrically with a mixture of glucose and amino acids either with AlaGln or without AlaGln. At 48 hours after irradiation, parameters of whole-body protein metabolism and DNA synthesis in intestinal mucosa were investigated using a primed, continuous infusion of [1-¹⁴C]leucine and [³H]thymidine. In addition, we evaluated the effect of irradiation and AlaGln on gut morphology, blood count and amino acid concentrations in blood plasma and skeletal muscle. Control rats were not irradiated but were given identical treatment. An increase in whole-body leucine oxidation, and insignificant changes in whole-body proteolysis and in protein synthesis were observed after irradiation. In irradiated rats we observed a decrease in muscle glutamine concentration, a decrease in protein synthesis in jejunum, colon and heart, and an increase in synthesis of proteins of blood plasma and spleen. Morphological examination and measurement of DNA synthesis failed to demonstrate any favorable effect of AlaGln supplementation on irradiated gut. However, administration of AlaGln resulted in a decrease in whole-body proteolysis and leucine oxidation which caused an increase in the fraction of leucine incorporated into the pool of body proteins. We conclude that the data obtained demonstrate that irradiation induces metabolic derangement associated with increased oxidation of essential branched-chain amino acids (valine, leucine and isoleucine) and that these disturbances can be ameliorated by administration of AlaGln. Received February 14, 2000 Accepted July 12, 2000