Protective systems of immunocompetent organs in fishes from different ecological and systematic groups

This article presents the results of analysis of parameters of the immune, antioxidant, and monooxygenase systems in the immunocompetent organs (pro- and mesonephros, spleen, and liver) of species belonging to different systematic and ecological groups, namely, northern pike Esox lucius, zander Sander lucioperca, and bream Abramis brama. Although having the same features in the functioning of homeostatic mechanisms in the species under study, significant differences were revealed between bream and another two species with respect to the parameters of the nonspecific immunity of tissues and enzyme systems that perform protective functions. In all the three species, the basic role in processes of immunopoesis and nonspecific protection is played by the kidneys and spleen, while the greatest values of the parameters of antioxidant defenses and ethoxyresorufin-O-deethylase activity were recorded in the liver.     

Activity of proteinases in fish of different ecological groups and their potential food items

The paper cites evidence on the activity of casein- and hemoglobinlytical proteinases of mucosa of the digestive tract of nine species of freshwater bony fish differing in their pattern of feeding, as well as in the whole organism of their potential prey. It was demonstrated that the ratio of proteinase activity with respect to casein and hemoglobin in the intestine mucosa of consumers and in the whole organism of their food items is different. In mucosa of fish intestine, the activity of caseinlytic proteinases is higher than the activity of hemoglobinlytic proteinases. In the whole organism of juvenile fish and invertebrates, on the other hand, the activity of hemoglobinlytic proteinases is higher.     

Rethinking ecological inference: density dependence in reef fishes

We use a meta‐analysis of density dependence in reef fishes to evaluate how ecologists approach detection, inference, and estimation. We compared two groups of studies: those that detected effects of density on survival and those that did not. Distinctions between these groups have spawned heated debate about the processes that affect fish dynamics. Per capita effects of density were similar between the two groups, although total effects (and hence ambient density) were greater in studies that detected density effects. The majority of the variation in effects of density was not resolved by the classification of studies based on the authors' conclusions. These results suggest (1) that standard inferences based on null hypothesis tests may miss important sources of variation in effects and give rise to unnecessary debate; and (2) that estimation of effect sizes and model parameters (including their uncertainty) is a powerful alternative to detection of ecological processes.     

Some specific features of vaginal microflora depending on ecological factors

In 75 female residents of Vladikavkaz, aged 18-45 years, who had applied to the gynecological department with complaints of vaginal discharge, the qualitative and quantitative composition of vaginal microflora was studied. All these women were divided into 2 groups: group 1 including 38 women living in ecologically unfavorable districts of the city and group 2 including 37 women living under ecologically favorable conditions. The relationship between the ecological situation of the districts of residence and vaginal microflora in women of the reproductive age was established. Unfavorable exogenous factors were found to lead to the development of vaginal dysbacteriosis: a sharp decrease in the amount of lactoflora or its complete absence accompanied by increased amount of staphylococci, enterococci, Escherichia coli, Proteus, Klebsiella and yeast-like fungi of the genus Candida.     

Comparative analysis of the ligninolytic potential of basidiomycetes belonging to different taxonomic and ecological groups

Screening of the ligninolytic activity of basidiomycetes from the Komarov Botanical Institute Basidiomycetes Culture Collection (LE-BIN), Russian Academy of Sciences, belonging to different taxonomic and ecological groups was performed. The patterns of the position of taxa of active producers of ligninolytic enzymes in the modern system of fungi were identified. Cluster analysis showed that the group of fungi with the greatest ligninolytic and degradation potential includes representatives of the families Pleurotaceae, Polyporaceae, and Phanerochaetaceae, which perform the first stages of wood decomposition. As a result, species of interest for the further study of their oxidative potential and use in biotechnology were selected.     

Effect of temperature on proteinase activities in intestinal chyme and mucosa of fish of different ecological groups

Effect of temperature on activities of proteinases in intestinal chyme and mucosa was studied in three fish species (pike-perch, zope, roach) belonging to different ecological groups by their nutrition type. There was revealed a significant difference of dependence of enzyme activities in chyme on temperature in the benthophage, roach (a higher level of relative activity in the range of lower temperatures and a wider zone of temperature optimum) as well as of values of apparent energy of activation of the protein hydrolysis process as compared with that in planktoand ichtyophages, zope and pike-perch, which indicates a significant effect of the enteral microbiota proteinases and of nutrition objects on characteristics of hydrolases functioning in fish intestine.     

Symbiotic microorganisms, a key for ecological success and protection of plants

Plant-associated microbial diversity encompasses symbionts, protecting their host against various aggressions. Mycorrhizal and rhizospheric microorganisms buffer effects of soil toxic compounds and soil-borne pathogens. Endophytic bacteria and fungi, some of which are vertically inherited through seeds, take part in plant protection by acting directly on aggressive factors (mainly pathogens and herbivores) or by enhancing plant responses. Plant protective microbial symbionts determine the ecological success of plants; they drastically modify plant communities and related trophic webs. This review suggests approaches to improve the inventory of diversity and functions of in situ plant-associated microorganisms.     

Effect of new antimicrobial agents on the ecological balance of human microflora

The human normal microflora is relatively stable at each ecological habitat under normal circumstances and acts as a barrier against colonization by potentially pathogenic microorganisms and against overgrowth of already present opportunistic microorganisms. Administration of antimicrobial agents causes disturbances in the ecological balance between the host and the normal microflora. The risk of emergence and spread of resistant strains between patients and dissemination of resistant determinants between microorganisms is reduced if colonization resistance is not disturbed by antimicrobial agents. In this article, the potential ecological effects of administration of new antimicrobial agents on the intestinal and oropharyngeal microflora are summarized. The review is based on clinical studies published during the past 10 years.     

Nitrate,nitrate reduction and organic nitrogen in plants from different ecological and taxonomic groups of Central Europe

Summary 48 plant species of the families Asteraceae, Chenopodiaceae, Ericaceae, Fabaceae, Lamiaceae, Polygonaceae and Urticaceae were investigated in 14 natural habitats of Central Europe having different nitrate supplies, with respect to their nitrate content, nitrate reductase activity (NRA) and organic nitrogen content. Plants that were flowering were selected where possible for analysis. The plants were subdivided into flowers, laminae, petioles+shoot axes and below-ground organs. Each organ was analyzed separately. Differences among species were found for the three variables investigated. Apart from the Fabaceae, which had particularly high concentrations of organic N, these differences reflect mainly the ecological behaviour, i.e. high nitrate and organic N contents and NRA values per g dry weight were found in species on sites rich in nitrate, and vice versa. Nitrate content, NRA and organic N content were correlated with nitrogen figures of Central European vascular plants defined by Ellenberg (1979). By use of regression equations this correlation was tested with species from other systematic groups. Some species were attributed with calculated N figures for the first time.     

Inadequacy of species-level designations for ecological studies of coastal migratory fishes

Synopsis The species is not always appropriate as a unit of measure when used in quantitative ecological studies. Analyses of fish trophic relationships in coastal areas indicate that, in many instances, more substantial ecological differences exist among life stages of a given species than among similar trophic units of different species. The use of a species in quantitative ecological studies can lead to problems of interpretation concerning the relationships of coastal fishes to complex habitats. Use of the species as a convenient unit of measure substitutes a basically taxonomic entity for more relevant life-history stages in ecological determinations. Niche breadth of a given species can be so extensive that quantitative determinations of significant ecological processes are difficult to make. Migratory coastal fishes undergo diverse ontogenetic trophic transformations. Without adequate recognition of the complex ecological stages that characterize such fishes, the oversimplification that characterizes many ecological studies in coastal areas will continue. This simplification, and the attendant overgeneralization that follows, tends to add to the continuing problem of unverified models and the inability to identify causal relationships in estuarine and coastal systems. Quantitative ecological studies would benefit from an approach that includes the use of identifiable, ontological trophic entities.     

Some ecological relationships of larval ascaridoids from south-eastern Queensland marine fishes

Nine larval types within the genera Anisakis, Terranova, Thynnascaris and Contracaecum were recovered from south-eastern Queensland marine fishes. Data on (i) incidence, (ii) intensity of infection, (iii) host diet and (iv) habitat for each type suggest Anisakis is an open water type, Contracaecum an inshore, shallow water type and both Terranova and Thynnascaris have intermediate distributions. Host diets indicate Anisakis and Terranova are found in predators of nekton, Contracaecum and Thynnascaris in benthic feeders.     

Parallel ecological diversification in Antarctic notothenioid fishes as evidence for adaptive radiation

Antarctic notothenioid fishes represent a rare example of a marine species flock. They evolved special adaptations to the extreme environment of the Southern Ocean including antifreeze glycoproteins. Although lacking a swim bladder, notothenioids have diversified from their benthic ancestor into a wide array of water column niches, such as epibenthic, semipelagic, cryopelagic and pelagic habitats. Applying stable carbon (C) and nitrogen (N) isotope analyses to gain information on feeding ecology and foraging habitats, we tested whether ecological diversification along the benthic–pelagic axis followed a single directional trend in notothenioids, or whether it evolved independently in several lineages. Population samples of 25 different notothenioid species were collected around the Antarctic Peninsula, the South Orkneys and the South Sandwich Islands. The C and N stable isotope signatures span a broad range (mean δ¹³C and δ¹⁵N values between ?25.4‰ and ?21.9‰ and between 8.5‰ and 13.8‰, respectively), and pairwise niche overlap between four notothenioid families was highly significant. Analysis of isotopic disparity‐through‐time on the basis of Bayesian inference and maximum‐likelihood phylogenies, performed on a concatenated mitochondrial (cyt b) and nuclear gene (myh6, Ptr and tbr1) data set (3148 bp), showed that ecological diversification into overlapping feeding niches has occurred multiple times in parallel in different notothenioid families. This convergent diversification in habitat and trophic ecology is a sign of interspecific competition and characteristic for adaptive radiations.     

Body size and ecological diversification in a sister species pair of triplefin fishes

The effect of body size on spatial resource competition and reproductive isolation was examined in a sister species pair of subtidal triplefin fishes (F. Tripterygiidae) in New Zealand. Ruanoho decemdigitatus and Ruanoho whero have overlapping sympatric distributions and differ in body size, attaining a total length of 12 cm and 9 cm, respectively. R. decemdigitatus was most commonly found in sheltered areas shallower than 5 m, while R. whero was frequently found in sheltered to moderately exposed areas down to 20 m. In sites where the species co-occurred, R. whero was less associated with rock substratum. The effect of body size on substratum use was investigated using laboratory trials based on the field data to test habitat preference and competitive ability in a common setting. Reproductive behaviour was assessed in courtship, mate choice and hybridisation trials. Both species exhibited similar habitat preferences, but large R. decemdigitatus were dominant in inter- and intraspecific contests for the preferred rock habitat, while small R. whero were displaced into less preferred habitats. Courtship behaviour in R. whero was a subset of that displayed by R. decemdigitatus, while no mating behaviour was observed in heterospecific trials. Female R. whero showed a strong preference for smaller males, while female R. decemdigitatus had no preference for male size. Results suggest that body size differences in the Ruanoho pair are consistent with female choice for smaller males in R. whero and competition for habitat in both species. Body size in the Ruanoho species appears to be influenced by conflicting selection pressures that may differ between the species.     

Some remarks on ecological groups of aquatic organisms

An analysis of several publications discussing versions of the conception of ecological groups of aquatic organisms in mountain streams and overgrowths of higher aquatic plants has been performed.     

Effect of temperature on proteinase activites of enteral microbiota and intestinal mucosa of fish of different ecological groups

Effect of temperature on proteinases activities of enteral microbiota and of intestinal mucosa was studied in five fish species (roach Rutilus rutilus, crucian carp Carassius carassius, common perch Perca fluviatilis, pike-perch Zander lucioperca, and pike Esox lucius) belonging by the nutrition type to different ecological groups. Essential differences of temperature characteristics of proteinases of intestinal mucosa and of enteral microbiota are revealed in fish belonging to different ecological groups. The character of the t-function of proteinases of intestinal mucosa and enteral microbiota for casein and hemoglobin as a rule is different. The values of the apparent E _act proteinases of intestinal mucosa for casein in most cases are higher than those of enteral microbiota, while those for hemoglobin, on the contrary, are lower. The lowest values of relative proteinase activities for casein in the zone of low temperatures (38 and 45.3% of the maximal activity) and the E_act value (less than 2.0 kcal/mol) are found at study of proteinases of enteral microbiota in common perch and crucian carp. The latter indicates a significant adaptability of the enteral microbiota proteinases of common perch and crucian carp to functioning at low temperatures.