Strong changes in lipoproteins and autoantibodies of blood serum of the Tundra Nency population as a result of environmental radiation on the territory they inhabit

As a result of large-scale nuclear tests on the Novaya Zemlya test site (1955-62) the Tundra Nentsy population of Yamal-Nentsy autonomous region (YNAR) fell under the constant influence of incorporated radioactive isotopes (137Cs and 90Sr). Therefore, it is very important to analyze a possible spectrum of diseases of Tundra Nentsy population.     

Strong Changes in Lipoproteins and Autoantibodies of Blood Serum of the Tundra Nency Population as a Result of Environmental Radiation on the Territory they Inhabit

As a result of large‐scale nuclear tests on the Novaya Zemlya test site (1955–62) the Tundra Nentsy population of Yamal‐Nentsy autonomous region (YNAR) fell under the constant influence of incorporated radioactive isotopes (¹³⁷Cs and ⁹⁰Sr). Therefore, it is very important to analyze a possible spectrum of diseases of Tundra Nentsy population.     

Raindrop Momentum Triggers Growth of Leaf-Associated Populations of Pseudomonas syringae on Field-Grown Snap Bean Plants

Observational and microclimate modification experiments were conducted under field conditions to determine the role of the physical environment in effecting large increases in phyllosphere population sizes of Pseudomonas syringae pv. syringae, the causal agent of bacterial brown spot disease of snap bean (Phaseolus vulgaris L.). Comparisons of daily changes in population sizes of P. syringae on three plantings of snap bean cultivar Cascade and one of cultivar Eagle with weather conditions indicated a strong association of rainfalls with periods of 1 to 3 days in duration during which increases in bacterial population sizes were greater than 10-fold and up to 1,000-fold. The effects of rain on populations of P. syringae were explored further by modifying the microclimate of bean plants in the field with polyethylene shelters to shield plants from rain and fine-mesh inert screens to modify the momentum of raindrops. After each of three separate intense rains, the greater-than-10-fold increases in population sizes of P. syringae observed on plants exposed to the rains did not occur on plants in the shelters or under the screens. The screens decreased the velocity and, thus, the momentum of raindrops but not the volume or quality of rainwater that fell on plants under the screens. Thus, the absence of increases in population sizes of P. syringae on plants under the screens suggests that raindrop momentum plays a role in the growth-triggering effect of intense rains on populations of P. syringae on bean plants under field conditions.     

Production of Spirulina biomass: Maintenance of monoalgal culture outdoors

The effects of sodium bicarbonate concentration, population density, and temperature on the maintenance of an outdoor monoculture of the cyanobacterium Spirulina platensis were studied. A clear response by Spirulina to the concentration of bicarbonate was evident, with 0.2M bicarbonate representing the lowest concentration in which a monoculture could be maintained. When the temperatures fell during the winter period to some 20-25 degrees C below the optimum for Spirulina, Chlorella sp. gradually increased and became the dominant species in the culture. Raising the temperature by covering the pond with transparent polyethylene resulted in a sharp decline in the population of Chlorella, and a gradual resumption of species dominance by Spirulina. In winter, there was an inverse relationship in the pond between the population density of Spirulina and the extent of contamination by Chlorella sp.; but no such effect was observed under field conditions at temperatures higher than 25 degrees C.     

Population structure of Alexandrium (Dinophyceae) cyst formation-promoting bacteria in Hiroshima Bay, Japan

A total of 31 bacterial isolates that have potential Alexandrium cyst formation-promoting activity (Alex-CFPB) were isolated from Hiroshima Bay (Japan), which is characterized by seasonal blooms of the toxic dinoflagellate Alexandrium tamarense. The population structure of Alex-CFPB was analyzed by means of restriction fragment length polymorphism analysis of the 16S rRNA genes (16S rDNA). Fourteen ribotypes, A to N, were observed among the 31 isolates of Alex-CFPB by using four restriction enzymes, MboI, HhaI, RsaI and BstUI. Among them, seven isolates, which were obtained from the seawater samples taken during the peak and termination periods of the A. tamarense bloom in 1998, belonged to ribotype A. This result suggests that bacterial strains of ribotype A may be dominant in the Alex-CFPB assemblages during these periods. The partial 16S rDNA-based phylogenetic tree of 10 ribotypes studied showed that nine of them fell into the Rhodobacter group of the alpha subclass of the Proteobacteria: Eight of nine ribotypes of the Rhodobacter group fell into the lineage of the Roseobacter subgroup, and one fell into the Rhodobacter subgroup. The non-Rhodobacter group type fell into the Marinobacterium-Neptunomonas-Pseudomonas group of the gamma-Proteobacteria: Isolates of Alex-CFPB ribotypes A and C do not have clear growth-promoting activities but have strong cyst formation-promoting activities (CFPAs) under our laboratory conditions. These results show that the Alex-CFPB assemblage may consist of various bacteria that belong mainly to the Roseobacter group and have strong CFPAs. These results suggest that not only the Alexandrium cyst formation-inhibiting bacteria (Alex-CFIB) reported previously but also Alex-CFPB, especially bacteria of ribotype A, may play significant roles in the process of encystment and bloom dynamics of Alexandrium in the natural environment.     

Foot-trembling and feeding behaviour in the Ringed Plover Charadrius hiaticula

The Merlin population in Orkney has undergone a marked decline during the 1980s. Site occupancy fell from 42% to 14% between 1981 and 86, while mean breeding success fell from 48% during 1975–81 to 29% during 1982–86. Mean brood size of successful nests declined from 3.3 during 1975–80 to 2.5 during 1981–87. Most breeding failures occurred during incubation. Loss and degradation of habitat, disturbance, weather, predation, organo-chlorine contamination and mercury contamination were examined as possible causes.     

Biomass granulation in an aerobic:anaerobic-enhanced biological phosphorus removal process in a sequencing batch reactor with varying pH

Long-term influences of different steady-state pH conditions on microbial community composition were determined by fluorescence in situ hybridization (FISH) in a laboratory scale reactor configured for enhanced biological phosphorus removal (EBPR). Chemical profiles were consistent with shifts in populations from polyphosphate-accumulating organisms (PAO) to glycogen-accumulating organisms (GAO) when pH fell from pH 7.5 to 7.0 and then to 6.5. While biomass was both dispersed and flocculated at pH 7.5, almost complete granulation occurred gradually after pH was dropped to 7.0, and these granules increased in size as the pH was reduced further to 6.5. Reverting back to pH 7.5 led to granule breakdown and corresponding increases in anaerobic phosphate release. Granules consisted almost entirely of Accumulibacter PAO cells, while putative GAO populations were always present in small numbers. Results suggest that low pH may contribute to granulation under these operational conditions. While chemical profiles suggested the PAO:GAO balance was changing as pH fell, FISH failed to reveal any marked corresponding increase in GAO abundances. Instead, TEM evidence suggested the Accumulibacter PAO phenotype was becoming more like that of a GAO. These data show how metabolically adaptable the Accumulibacter PAO can be under anaerobic:aerobic conditions in being able to cope with marked changes in plant conditions. They suggest that decreases in EBPR capacity may not necessarily reflect shifts in community composition, but in the existing population metabolism.     

Assessment of the status of biological health of the population of tundra Nentsy inhabiting northwestern Siberia from data on analysis of autoantibodies and lipoproteins from blood donors

As a result of large-scale nuclear explosion on Novaya Zemlya test site (1955-62) the Tundra Nentsy population of Yamal-Nentsy autonomous region (YNAR) fell under constant influence of incorporated radioactive isotopes (137Cs and 90Sr). Therefore, it is very important to analyze a possible spectrum of diseases of Tundra Nentsy population. We have developed recently a new method for determination of concentrations of all main fraction and subfraction of lipoproteins (LP, 30 parameters) in human sera using small-angle X-ray scattering, and a general mathematical model to describe LP composition in human blood. The analysis of the 30 parameters characterizing fine spectrum of LPs in 374 YNAR natives showed that only approximately 10% of the donors are normal, while the indices for approximately 90% of the test subjects fall into the range of different pathologies (3-8% incidence in normal population, according to epidemiological studies). Moreover, we found that approximately 41% of European and approximately 56% of Tundra Nentsy have high level of autoantibodies to DNA and cardiolopine like the same for autoimmune diseases patients.     

CYTOKINETIC CHANGES IN THE THYMUS OF TUMOUR-BEARING AND OF DEXAMETHASONE-TREATED MICE

Changes in the cell population kinetics of the Balb/c mouse thymus were studied (a) during the growth of a syngeneic transplantable sarcoma and (b) following intraperitoneal injection of dexamethasone. The weight of the thymus fell briefly after tumour transplantation, then recovered with overshoot and eventually declined profoundly. After dexamethasone injection the weight of the thymus fell to roughly one-third of its normal value in 36 hr. Similar cytokinetic changes were observed in both sets of experiments; thymic wasting was accompanied by a small increase in thymocyte cell cycle time, a prolongation of the S-phase of the cycle, a marked decrease in the thymocyte cell production rate and a marked reduction in the growth fraction of the thymocyte population in the superficial Cortex. It is suggested that thymic atrophy in tumour bearing animals may be a stress phenomenon.     

Microbial responses to salt-induced osmotic stress

Summary Soil columns were exposed to balanced (low Na⁺) or unbalanced (high Na⁺) high-salt solutions for a period of 7 days followed by 7 days of stress reflief. Total numbers of bacteria released into the perfusates rose under both types of stress, but the proportion of displaced bacteria that were viable fell significantly. Relief from both types of stress stimulated rapid increases in the number of viable micro-organisms released from soil. Examination of the soils at the end of the relief periods revealed that soils exposed to stress contained more viable bacteria than the non-stressed controls. However, high levels of balanced stress led to a significant decrease in species diversity within the microbial population, but a similar effect was not observed in soils exposed to unbalanced, high Na⁺ stress. These results suggest that, while salt stress may cause a significant reduction in the number of microorganisms in a soil, a large portion of the microbial population can rapidly adapt to marked changes in salinity.     

THE BEHAVIOUR OF ADULT CLICK BEETLES OF THE GENUS AGRIOTES (A. OBSCURUS L., A. LINEATUS L., AND A. SPUTATOR L.)

Various methods of trapping click beetles were tried, the aim being to devise a method which could be used for population and movement studies in grass fields. It is shown that a trap consisting of a 3 in. thickness of hay over closely clipped grass is suitable for this purpose. Annual and daily activity are discussed. Maximum activity occurred in late May and early June, and during the afternoon and evening. The beetles showed a preference for the most humid sites during dry weather. Numbers fell as the hedge was approached and very few occurred under the hedge. Marked beetles were released, and the maximum distance at which they were recovered was 26 yards (23.8 m.). The majority moved in a very restricted area.     

The cell in starvation; physiological and chemical observations

Observations made on Amoeba proteus during total inanition revealed the following changes: Dry weight declined progressively, but at a decreasing rate to about 45 per cent of the initial levels when determined in surviving members of a dying population. Protein fell to about 70 per cent of the initial level. A hexane-alcohol extractable component fell during early starvation then rose to about its initial absolute level in the dying cells. While initially most of this component is probably lipide, it is not certain that other materials are not extracted during cell degeneration. Survival as a function of cell size was studied. No advantage in survival was apparent for any size class. Nucleate cell "halves" likewise showed no survival time differential, unlike a highly significant decrease in the survival of enucleate portions. The maintenance of the initial variance about the mean population weight (after hexane-alcohol extraction) during starvation, likewise supports the idea that survival depends largely on concentration parameters.     

The use of canonical analysis for selection within a population of spring barley

A selection method is described involving the application of canonical analysis to data for a number of measured traits in a composite population of spring barley grown in two seasons. Lines were selected which fell within the Euclidean space defined by the range, for a number of standard cultivars, on each significant canonical variate. Alternatively, limits were fixed for an acceptable range for each trait and transformed to canonical variates. Lines were selected which fell nearest to the centroid of this acceptable space. The method might be used as an alternative to the selection index method where difficulty is often encountered in assigning appropriate economic weightings to the traits measured.     

THE CELL IN STARVATION: PHYSIOLOGICAL AND CHEMICAL OBSERVATIONS

Observations made on Amoeba proteus during total inanition revealed the following changes: Dry weight declined progressively, but at a decreasing rate to about 45 per cent of the initial levels when determined in surviving members of a dying population. Protein fell to about 70 per cent of the initial level. A hexane-alcohol extractable component fell during early starvation then rose to about its initial absolute level in the dying cells. While initially most of this component is probably lipide, it is not certain that other materials are not extracted during cell degeneration. Survival as a function of cell size was studied. No advantage in survival was apparent for any size class. Nucleate cell "halves" likewise showed no survival time differential, unlike a highly significant decrease in the survival of enucleate portions. The maintenance of the initial variance about the mean population weight (after hexane-alcohol extraction) during starvation, likewise supports the idea that survival depends largely on concentration parameters.     

The population ecology of the Australian gekkonid lizard Heteronotia binoei in an exploited forest

The main factors affecting population size were investigated in a population of Heteronotia binoei the general biology of which was already well known. Population size fell by about 40% during a two year observation period and this appeared to have been due to adverse climatic effects greatly depressing egg incubation success. The effect of this was soon apparent as H. binoei is a short-lived species.
An upper limit to population size appears to be set by social behaviour (territoriality) acting in conjunction with the available home-sites. When population size is large the effects of this are buffered to some degree by overspill into an inferior home-site.     

Evidence for contrasting modes of selection at interacting globin genes in the European rabbit (Oryctolagus cuniculus)

In hybrid zones between genetically differentiated populations, variation in locus-specific rates of introgression may reflect adaptation to different environments or adaptation to different genetic backgrounds. The European rabbit, Oryctolagus cuniculus, is well-suited to studies of such hybrid zone dynamics because it is composed of two genetically divergent subspecies that hybridize in a zone of secondary contact in central Iberia. A species-wide survey of allozyme variation revealed a broad range of locus-specific divergence levels (F(ST) ranged from 0 to 0.54, mean F(ST)=0.16). Interestingly, the two loci that fell at opposite ends of the distribution of F(ST) values, haemoglobin alpha-chain (HBA) and haemoglobin beta-chain (HBB), encode interacting subunits of the haemoglobin protein. The contrasting patterns of spatial variation at these two loci could not be reconciled under a neutral model of population structure. The HBA gene exhibited higher-than-expected levels of population differentiation, consistent with a history of spatially varying selection. The HBB gene exhibited lower-than-expected levels of population differentiation, consistent with some form of spatially uniform selection. Patterns of linkage disequilibrium and allele frequency variation do not appear to fit any simple model of two-locus epistatic selection.     

The structure and dynamics of woodreed Calamagrostis canescens population: a modelling approach

A scale of ontogenetic states has been developed for woodreed Calamagrostis canescens, a perennial species dominating the grass layer of fell forest areas. The population structure is considered as a set of age-stage groups of individuals differing both in the ontogenetic stage and the chronological age measured in years. to describe the dynamics through years a special kind of matrix formalism has been proposed which is reducible neither to the classic Leslie matrix for an age-structured population, nor to the well-known Lefkovitch matrix for a stage-structured one, and which does not suffer from excessiveness of the "two-dimensional" representation for the structure implying the projection matrix of a block pattern. It has been shown however that the protection matrix corresponding to C. canescens life-history graph embodies the canonical features of matrix formalism for structured population dynamics, such as the exponential population growth or decline, the convergence to a stable equilibrium structure, the calculable indicator of growth/decline/equilibrium (i.e., a measure of the population reproductive potential) as well as possibility to determine the relative reproductive value of each group. On the other hand, "left-sidedness of the age spectrum", a property that is often observed in real populations and is inherent in Leslie models of growing populations, may fail in the age-stage-structured model. The aggregation of age-stage groups into the age classes is possible only under special strict relationship among the age-stage-specific vital rates of the population. The both circumstances serve a methodical indication that an additional dimension such as the stages, for example, ought to be introduced into the age structure of the model population.     

Breeding and moulting shelduck (Tadorna tadorna) of the Severn Estuary

Aerial and ground censuses of Shelduck in 1988 found a summering population of 2000–2700 birds until early July. Territorial pairs, non-breeding aggregations and ultimate brood rearing nursery areas were associated with extensive areas of mudflats (Peterstone Wentlooge, Uskmouth-Collister Pill, Oldbury-Littleton and Purton-Frampton). Bridgwater Bay continues to be the most important moulting area away from the Wadden Sea, with just under 2000 present at peak count in late July. At least 94 pairs established territories along the shores of the Severn, with perhaps as many as 80 more on Flatholm, giving rise to at least 49 broods. Duckling survival was low in 1988: mean brood size fell from 9.3 to 3.3 between hatching and fledging. Breeding success in different parts of the estuary shows no consistent trends.     

ENHANCED GROWTH RATES OF THE GERMLINGS OF CYANOBACTERIAL RESTING SPORES (AKINETES)

In experiments with the toxic cyanobacterium, Anabaena circinalis , we investigated the nature of cyst formation and germination under different environmental conditions (variation in light quality and quantity, temperature, nutrient limitation). We consistently found that germlings up to about 5 days old had greater growth rates than those of vegetative cells grown under similar saturating irradiance and excess nutrient conditions in batch culture. Averaging the results from 4 experiments, the specific growth rate (K') fell from 1.9 d-1, 24 hours after germination to 1.17, 1.04, 0.8, and to 0.45 d⁻¹ after 48, 72, 120 and 144 hours, respectively. This equates to an increase in generation time from 0.37 to 1.54 days over this 6 day period. To investigate the implications of these results we modelled two hypothetical populations, A & B, with an initial akinete or resting cyst concentration of 10/mL each, but with population A having a standard growth rate of 0.45 and B with the 6 day early enhanced growth rate as determined in our laboratory experiments. The model indicates that population B quickly establishes dominance over population A. In this modeling exercise we have assumed a germination frequency of 100% for both populations but our laboratory results indicate that even given optimum germination conditions this factor may vary between 5% and 90% depending on the age of akinetes and the conditions experienced during dormancy (senescence). Some conditions that determine germination frequency were also investigated.