Dynamics of skeleton formation in the Lake Baikal sponge Lubomirskia baicalensis. Part II. Molecular biological studies

In a preceding study it has been reported that the freshwater sponge Lubomirskia baicalensis, living in Lake Baikal (East Siberia), is composed of spicules forming a characteristic pattern which follows radiate accretive growth. Here we report that the spicules are synthesized by the enzyme silicatein, a protein which is related to cathepsin L. The cDNAs for silicatein and the related cathepsin L were isolated and used as probes to show that the mRNA levels of silicatein in the bases of the spicule skeleton of the animals are low, while the mRNA level of cathepsin L in this region exceeds that of the growing zone. This is the first comprehensive study on the importance of the axial filament/silicatein as an essential structural and functional component determining the growth and stability of demosponge spicules.Note: Sequences from Lubomirskia baicalensis have been deposited in the EMBL/GenBank; cDNAs for the putative silicatein (LBSILICA) are deposited under the accession no. AJ786771 and for cathepsin L (LBCATL) under the accession no. AJ786770.     

The sensitivity of mussel-watch programmes to detect temporal trends in the bio-availability of metals. A case study of the Saronicos Gulf of Greece

Statistical power analysis has been used to determine the sensitivity of the mussel-watch programme in Hellenic seas, with particular focus placed on the data obtained for metal content in mussels from the Saronicos Gulf during the period 1985-1997. Sample collection was carried out quarterly. Soft tissues of 60-100 similarly sized mussels (Mytilus galloprovincialis) were pooled into six composite samples and analysed by Atomic Absorption Spectroscopy (AAS). The study concludes that the resolution of monitoring programmes employed thus far is sufficiently high to detect temporal trends related to changes in contaminant levels caused either by drastic environmental control (such as those imposed on point-source pollutants) or by sudden increases in contaminant load. However, the detection of more subtle trends, which may be expected in the near future as a result of global pollution-control policies, is likely to require the adoption of much more sensitive programmes. In addition, the review of up-to-date knowledge on metal biology in mussels suggests that factors related to growth and reproduction should be taken into account to remarkably increase the resolution of mussel-watch programmes. Indicative maximum values for components of error to be complied with during routine monitoring are suggested.     

Colonization of surfaces by phenolic compounds utilizing microorganisms

The aim of the present study is to determine optimal adhesive interaction of phenolic compounds utilizing Candida maltosa and Rhodococcus erythropolis when adhering to kaolin, silicone, synthetic foil (Steriking R40) and fluorinated silicones, comparing cell and support surface hydrophobicity. In parallel, the interfering effect of detergents was investigated. Data obtained show that the less hydrophobic supports display high initial cell adhesion when contacted with the cell type with a lower surface hydrophobicity (yeast cell) but most stable yeast biofilms are those formed on highly hydrophobic fluorinated silicones. On the other hand, support hydrophobicity has no effect on bacterial cell detachment; however, bacterial biofilms are denser when growing on more hydrophobic supports. Both detergents interfere (independently on the cell type) with the early and late phases of biofilm development.     

Acute and sublethal toxicity tests to monitor the impact of leachate on an aquatic environment

In this study, a specific landfill leachate (1200 mg l(-1) COD and 600 mg l(-1) BOD(5)) was used to develop a standardised short-term acute and longer-term sublethal ex-situ toxicity testing programme, in order to determine the potential ecological implications of leaching contaminants reaching the water table. Bioassays were undertaken with juvenile Gammarus pulex and Asellus aquaticus macro-invertebrates. Preliminary acute test variables included static and static renewed flow rates for 96-h, starved and fed specimens, and aerobic and oxygen depleting conditions. However, regardless of any test variable, the lethal concentration (LC(50)) for A. aquaticus remained at 12.3% v/v leachate in deionized water, whilst that for G. pulex was only 1%. Sublethal toxicity was judged on the basis of frequency of births and the growth rate of newly born individuals. Tests showed that even a dilution as high as 1:66- would influence the fecundity of a Gammarus population, whilst a dilution of 1:20 would affect the size of an Asellus breeding colony.     

On monitoring anthropogenic airborne uranium concentrations and (235)U/(238)U isotopic ratio by Lichen - bio-indicator technique

Lichens are widely used to assess the atmospheric pollution by heavy metals and radionuclides. However, few studies are available in publications on using lichens to qualitatively assess the atmospheric pollution levels. The paper presents research results applying epiphytic lichens as bio-monitors of quantitative atmospheric contamination with uranium. The observations were conducted during 2.5 years in the natural environment. Two experimental sites were used: one in the vicinity of a uranium contamination source, the other one - at a sufficient distance away to represent the background conditions. Air and lichens were sampled at both sites monthly. Epiphytic lichens Hypogimnia physodes were used as bio-indicators. Lichen samples were taken from various trees at about 1.5m from the ground. Air was sampled with filters at sampling stations. The uranium content in lichen and air samples as well as isotopic mass ratios (235)U/(238)U were measured by mass-spectrometer technique after uranium pre-extraction. Measured content of uranium were 1.45 mgkg(-1) in lichen at 2.09 E-04 microgm(-3) in air and 0.106 mgkg(-1) in lichen at 1.13 E-05 microgm(-3) in air. The relationship of the uranium content in atmosphere and that in lichens was determined, C(AIR)=exp(1.1 x C(LICHEN)-12). The possibility of separate identification of natural and man-made uranium in lichens was demonstrated in principle.     

Transformation of ecological conditions of soil and humus substance formation in the urban environment

Ecological conditions of soil formation and specific features of humus substance formation are considered with regard to urban soils of different types formed in the following functional zones: the park zone, residential area, and sanitary protective zone of the Middle Ural Copper-Smelting Plant. The specificity of soil formation in Revda, a typical industrial city of the Middle Urals, is determined by the combined effect of urban and technogenic factors (urbogenesis and technogenesis), with the former being of primary importance. At a constant period of biological activity, the depth of humification is primarily a function of granulometric and chemical composition of urban soils.Translated from Ekologiya, No. 1, 2005, pp. 11–19.Original Russian Text Copyright © 2005 by Meshcheryakov, Prokopovich, Korkina.     

Estimation of the maximal population frequency of “alien” biotypes taking into account a priori data

A method is described for calculating the probability that the percentage of alien biotypes is higher than a specified threshold (e.g., 5%) in a population in which a certain number of alien biotypes has been found preliminarily. The method is based on the Bayesian approach; it assumes that the researcher has preliminary (a priori) information on the frequency of these biotypes. This a priori information makes it possible to estimate the aforementioned probability more accurately than is possible with the use of the standard binomial estimation. The method is illustrated by the results of the estimation of cultivar purity in batches of stock and foundation seeds of spring barley with the use of protein markers.Translated from Ekologiya, No. 2, 2005, pp. 106–109.Original Russian Text Copyright © 2005 by Zhivotovsky, Pomortsev, Lyalina, Kalabushkin, Pukhalskii.     

Gradient Genogeographic Analysis of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. Populations in Europe

Gradients of Nei's genetic distances between 15 samples of Pinus sylvestris L. trees were analyzed along three submeridional transects, from Scandinavia to the Mediterranean and Transcaucasia. As a result, distinct chorogenetic differentiation was revealed between the populations of this species growing in climatically specific regions of northern and southern Europe. Considerable Nei's distances (DN = 0.045–0.056) and their gradients, combined with differences in stable phenotypic characters (the composition of monoterpenes and morphological parameters of cones) determined at the Pyrenean and Caucasian mountain borders, suggest that the P. sylvestris species structure includes two South Eurasian subspecies, the Pyrenean P. sylvestris L., ssp. iberica Svoboda and the Transcaucasian P. sylvestris L., ssp. hamata (Stev.) Fomin.