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Results for “Environmental selection”

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PubMedDate not supplied

Immunochemical applications in environmental science.

Immunochemical methods are based on selective antibodies combining with a particular target analyte or analyte group. The specific binding between antibody and analyte can be used to detect environmental contaminants in a variety of sample matrixes. Immunoassay methods provide cost-effective, sensitive, and selective analyses for many compounds of environmental and human health concern. Immunoaffinity chromatography methods have been integrated with chromatographic methods and are also being used as efficient sample preparations prior to immunochemical or instrumental detection. Immunosensors show promise in obtaining rapid online analyses. These and other advancements in immunochemical methods continue the expansion of their role from field screening methods to highly quantitative procedures that can be easily integrated into the environmental analytical laboratory.

Animals↗

PubMed2003

[Selectivity and tolerance of sea urchin (Hemicentrotus pulcherrimus) to environmental change].

An experimental ecological study of sea urchin (Hemicentrotus pulcherrimus) sampled from coastal waters of Qingdao was focused on the fundamental ecological factors such as temperature, salinity, light intensity and substratum. The results showed that the suitable ecological range of temperature was from 8 degrees C to 22 degrees C, and the selectivity to temperature was changed with the previous living temperatures. Hemicentrotus pulcherrimus was a kind of stenohaline creature. Its optimum ecological range of salinity was from 30 to 35. The results also showed that Hemicentrotus pulcherrimus liked to select weak light environment (< 50 lux), especially under non-food condition. Hemicentrotus pulcherrimus had the positive substratum-selectivity to coarse sand and the negative substratum-selectivity to silver sand.

Animals↗

PubMed1995

Two retroviral infections of periparturient Holstein cattle: a phenotypic and genetic study.

Environmental and genetic factors affecting prevalences of antibodies to bovine leukosis virus and bovine immunodeficiency-like virus were studied on 137 periparturient Holstein cows selected for milk production. Environmental effects were obtained by logistic regression, and genetic parameters were determined using threshold animal models. Cows selected for high predicted transmitting ability for kilograms of milk fat plus protein had the highest prevalence of antibodies to bovine immunodeficiency-like virus and the lowest prevalence of antibodies to bovine leukosis virus. Heritability estimates for susceptibility to retroviral infections were close to zero.

Animals↗

PubMed1996

The limit to human longevity: an approach through a stress theory of ageing.

Survival to old age is enhanced by high vitality and resilience associated with substantial physiological and morphological homeostasis. This is underlain by genes for stress resistance, which confer high metabolic efficiency and hence adaptation to the energy costs of the stresses to which free-living populations are exposed. Under the stress theory of ageing, selection for genes for stress resistance is primary, and achieved life-span is secondary. In some human populations of the modern era, selection for stress resistance is less intense than in earlier times, because of adequate nutrition and reduced exposure to environmental stresses. Such relaxed selection should permit the accumulation of deleterious mutants that are likely to be stress sensitive. Accordingly, increased maximum life-span in future human populations would appear difficult to achieve.

Adaptation, Physiological↗

PubMed2006

Environmental performance policy indicators for the public sector: the case of the defence sector.

The development of environmental performance policy indicators for public services, and in particular for the defence sector, is an emerging issue. Despite a number of recent initiatives there has been little work done in this area, since the other sectors usually focused on are agriculture, transport, industry, tourism and energy. This type of tool can be an important component for environmental performance evaluation at policy level, when integrated in the general performance assessment system of public missions and activities. The main objective of this research was to develop environmental performance policy indicators for the public sector, specifically applied to the defence sector. Previous research included an assessment of the environmental profile, through the evaluation of how environmental management practices have been adopted in this sector and an assessment of environmental aspects and impacts. This paper builds upon that previous research, developing an indicator framework--SEPI--supported by the selection and construction of environmental performance indicators. Another aim is to discuss how the current environmental indicator framework can be integrated into overall performance management. The Portuguese defence sector is presented and the usefulness of this methodology demonstrated. Feasibility and relevancy criteria are applied to evaluate the set of indicators proposed, allowing indicators to be scored and indicators for the policy level to be obtained.

Conservation of Natural Resources↗

PubMed1996

Selective breeding for isolation-induced intermale aggression in mice: associated responses and environmental influences.

Aggressive (TA) and nonaggressive (TNA) lines of mice were established by selective breeding for isolation-induced intermale aggression. This paper summarizes and updates studies performed on the TA and TNA lines. The genetic analysis revealed that in these lines the genes for aggression are located on the autosomes and demonstrate a Mendelian segregation. The genes are expressed only in the presence of androgens which are normally present only in males. Behavioral and biological responses associated with high and low levels of aggression in TA and TNA mice are reviewed. Line differences have been found in olfactory communication and marking behavior, in maternal and predatory aggression in females, in locomotor activity, and in learning abilities. Also, correlated neurochemical and endocrinological responses to the selection have been detected. Maternal factors during the preweaning period do not significantly affect the development of aggression in TA and TNA males, while early postweaning exposure to aggression or sex enhanced later aggressive and sexual activity. Early experience and genetic disposition for aggression are correlated, with TA males showing the greatest increase in the behaviors studied.

Aggression↗

PubMed2000

Synthesis and evaluation of a molecularly imprinted polymer for selective on-line solid-phase extraction of 4-nitrophenol from environmental water.

A molecularly imprinted polymer (MIP) able to bind 4-nitrophenol (4-NP) was prepared using noncovalent molecular imprinting methods and evaluated as a selective sorbent in molecularly imprinted solid-phase extraction (MISPE) on-line coupled to a reversed-phase HPLC. It has been shown that the conditions chosen for washing the MIP and for eluting the analyte in the MISPE process are extremely important for ensuring good selectivity and recovery. River water samples, spiked with the 11 Environmental Protection Agency phenolic compounds at microgram per liter levels, were preconcentrated on-line using this MIP, and 4-NP was selectively extracted. The humic acid interference was simultaneously reduced considerably. The MIP was also compared with a commercially available highly cross-linked polymer (LiChrolut EN) and the former yielded cleaner extracts.

Chromatography, High Pressure Liquid↗

PubMed1992

Cellulose bearing covalently linked copper phthalocyanine trisulphonate as an adsorbent selective for polycyclic compounds and its use in studies of environmental mutagens and carcinogens.

A method useful as a preconcentration technique for isolating mutagens and carcinogens is described. Cotton bearing covalently linked copper phthalocyanine trisulphonate as ligand (blue cotton) can adsorb selectively compounds having three or more fused rings. The adsorption takes place in aqueous media, involving 1:1 complex formation between the ligand and the polycyclic compound. The desorption can be done by elution with organic solvents, most effectively with methanol containing ammonia. As many important environmental mutagens and carcinogens are polycyclics, this adsorption is useful as a means of extracting this class of materials from crude samples such as food, urine and river waters. The use of copper phthalocyanine as a ligand for chromatographic supports has recently been initiated, yielding promising results for the effective separation of polycyclic aromatic compounds from each other.

Adsorption↗

PubMed2001

The osmophobic effect: natural selection of a thermodynamic force in protein folding.

Intracellular organic osmolytes are present in certain organisms adapted to harsh environments and these osmolytes protect intracellular macromolecules against the denaturing environmental stress. In natural selection of organic osmolytes as protein stabilizers, it appears that the osmolyte property selected for is the unfavorable interaction between the osmolyte and the peptide backbone, a solvophobic thermodynamic force that we call the osmophobic effect. Because the peptide backbone is highly exposed to osmolyte in the denatured state, the osmophobic effect preferentially raises the free energy of the denatured state, shifting the equilibrium in favor of the native state. By focusing the solvophobic force on the denatured state, the native state is left free to function relatively unfettered by the presence of osmolyte. The osmophobic effect is a newly uncovered thermodynamic force in nature that complements the well-recognized hydrophobic interactions, hydrogen bonding, electrostatic and dispersion forces that drive protein folding. In organisms whose survival depends on the intracellular presence of osmolytes that can counteract denaturing stresses, the osmophobic effect is as fundamental to protein folding as these well-recognized forces.

Amino Acid Sequence↗

PubMed1993

Risk of agranulocytosis and aplastic anemia in relation to history of infectious mononucleosis: a report from the international agranulocytosis and aplastic anemia study.

The general objective of this study was to evaluate the risks of agranulocytosis and aplastic anemia in relation to drug use. Other potential risk factors, including history of infectious mononucleosis, were also evaluated. In an international population-based case-control study, cases of agranulocytosis and aplastic anemia and controls, who were patients with selected diagnoses, were identified from the same hospitals. Information on drug use was obtained in a structured interview. Limited information on environmental exposures and on selected items of medical history, including infectious mononucleosis, was also recorded. The possible effects of these factors on the risk of the two blood dyscrasias were evaluated. Relative risks were estimated by stratified analysis and by multiple logistic regression. Among 319 cases of agranulocytosis, 12 patients (4%) gave a history of infectious mononucleosis at least 1 year previously; among 2180 controls the corresponding number was 11 (0.5%) (multivariate relative risk estimate, 6.2; 95% confidence interval, 2.3-17). A nonsignificant elevation in the relative risk was observed for aplastic anemia. The data suggest that infectious mononucleosis may confer a long-term increase in the risk of agranulocytosis. However, the association was an unexpected one, identified in the course of multiple comparisons, and it must be independently confirmed.

Adolescent↗

PubMed2004

Clonal selection for transcriptionally active viral oncogenes during progression to cancer.

Primary keratinocytes immortalized by human papillomaviruses (HPVs), along with HPV-induced cervical carcinoma cell lines, are excellent models for investigating neoplastic progression to cancer. By simultaneously visualizing viral DNA and nascent viral transcripts in interphase nuclei, we demonstrated for the first time a selection for a single dominant papillomavirus transcription center or domain (PVTD) independent of integrated viral DNA copy numbers or loci. The PVTD did not associate with several known subnuclear addresses but was almost always perinucleolar. Silent copies of the viral genome were activated by growth in the DNA methylation inhibitor 5-azacytidine. HPV-immortalized keratinocytes supertransduced with HPV oncogenes and selected for marker gene coexpression underwent crisis, and the surviving cells transcribed only the newly introduced genes. Thus, transcriptional selection in response to environmental changes is a dynamic process to achieve optimal gene expression for cell survival. This phenomenon may be critical in clonal selection during carcinogenesis. Examination of HPV-associated cancers supports this hypothesis.

Cell Line, Transformed↗

PubMed2006

Capture probe conjugated to paramagnetic nanoparticles for purification of Alexandrium species (Dinophyceae) DNA from environmental samples.

AIMS: To develop a rapid, cost-effective and selective Alexandrium DNA extraction procedure from environmental samples in order to provide good-quality template for the downstream PCR-based detection assay. METHODS AND RESULTS: In this study, we tested a DNA extraction method based on silica-coated, superparamagnetic nanoparticles conjugated to a DNA-capture sequence (probe) complementary to a specific region of 5.8S rDNA of the genus Alexandrium. Cultured Alexandrium catenella cells were used as the harmful algal bloom species for the DNA extraction. Then, a PCR assay was performed with primers specific for the genus Alexandrium to assess the specificity and sensitivity of the nucleic acid extraction method. This method was applied to both cultured and field samples, reaching in both cases a detection limit of one A. catenella cell. CONCLUSIONS: The results suggest that the use of probe-conjugated paramagnetic nanoparticles could be effective for the specific purification of microalgal DNA in cultured or environmental samples, ensuring sensitivity and specificity of the subsequent PCR assays. SIGNIFICANCE AND IMPACT OF THE STUDY: The DNA extraction method optimized in this study represents a progress towards the rapid and efficient direct detection of Alexandrium cells in seawater monitoring. In fact, this method requires no other equipment than a magnet and a hybridization oven and, in principle, can be adapted to different toxic microalgal species and can be automated, allowing the processing of a high number of samples.

Animals↗

PubMed2006

Resolving the paradox of common, harmful, heritable mental disorders: which evolutionary genetic models work best?

Given that natural selection is so powerful at optimizing complex adaptations, why does it seem unable to eliminate genes (susceptibility alleles) that predispose to common, harmful, heritable mental disorders, such as schizophrenia or bipolar disorder? We assess three leading explanations for this apparent paradox from evolutionary genetic theory: (1) ancestral neutrality (susceptibility alleles were not harmful among ancestors), (2) balancing selection (susceptibility alleles sometimes increased fitness), and (3) polygenic mutation-selection balance (mental disorders reflect the inevitable mutational load on the thousands of genes underlying human behavior). The first two explanations are commonly assumed in psychiatric genetics and Darwinian psychiatry, while mutation-selection has often been discounted. All three models can explain persistent genetic variance in some traits under some conditions, but the first two have serious problems in explaining human mental disorders. Ancestral neutrality fails to explain low mental disorder frequencies and requires implausibly small selection coefficients against mental disorders given the data on the reproductive costs and impairment of mental disorders. Balancing selection (including spatio-temporal variation in selection, heterozygote advantage, antagonistic pleiotropy, and frequency-dependent selection) tends to favor environmentally contingent adaptations (which would show no heritability) or high-frequency alleles (which psychiatric genetics would have already found). Only polygenic mutation-selection balance seems consistent with the data on mental disorder prevalence rates, fitness costs, the likely rarity of susceptibility alleles, and the increased risks of mental disorders with brain trauma, inbreeding, and paternal age. This evolutionary genetic framework for mental disorders has wide-ranging implications for psychology, psychiatry, behavior genetics, molecular genetics, and evolutionary approaches to studying human behavior.

Adaptation, Physiological↗

PubMed1995

Mastitis of periparturient Holstein cattle: a phenotypic and genetic study.

Environmental and genetic factors affecting somatic cell scores, clinical mastitis, and IMI by minor and major pathogens were studied on 137 periparturient Holstein cows selected for milk production. Environmental effects were obtained by generalized least squares and logistic regression. Genetic parameters were from BLUP and threshold animal models. Lactation number affected the number of quarters with clinical mastitis and the number of quarters infected with minor pathogens. The DIM affected somatic cell score and number of quarters infected with major pathogens. Heritabilities for all mastitis indicators averaged 10%, but differences occurred among the indicators. Correlations between breeding values of the number of quarters infected with minor pathogens and the number infected with major pathogens were antagonistic and statistically significant.

Animals↗

PubMed2004

Frequency and microenvironmental pattern of selection on plastic shade-avoidance traits in a natural population of Impatiens capensis.

The frequency and predictability of different selective environments are important parameters in models for the evolution of plasticity but have rarely been measured empirically in natural populations. We used an experimental phytometer approach to examine the frequency, predictability, and environmental determinants of heterogeneous selection on phytochrome-mediated shade-avoidance responses in a natural population of the annual plant Impatiens capensis. The strength and direction of selection on shade-avoidance traits varied substantially on a fine spatial scale. The shade-avoidance phenotype had high relative fecundity in some microsites but was disadvantageous in other microsites. Local seedling density proved to be a surprisingly poor predictor of microenvironmental variation in the strength and direction of selection on stem elongation in this study population. At least some of this unpredictability resulted from microenvironmental variation in water availability; the shade-avoidance phenotype was more costly in dry microsites. Thus, environmental heterogeneity in resource availability can affect the relative costs and benefits of expressing shade-avoidance traits independent of local seedling density, the inductive environmental cue. Theory predicts that these conditions may promote local genetic differentiation in reaction norms in structured populations, as observed in I. capensis.

Adaptation, Physiological↗

PubMed1984

Dietary self-selection of laying hens inadequate to overcome the effects of high environmental temperature.

Two environmental temperatures, 21 and 30 C, were used during a 28-day experimental period. There were two groups of hens in each temperature treatment. The control groups (C) were given a conventional balanced diet and each dietary self-selection group (S-S) was provided, on an individual hen basis, three diets each one being high in energy, protein, or calcium. The S-S groups had significantly reduced egg production, which probably resulted from the significantly reduced protein intake. Egg weight and energy intake were reduced in the S-S group at 21 C while calcium intake and egg shell strength at 30 C were higher as compared to the corresponding C group. Dietary self-selection did not enable hens to regulate nutrient intake for comparable performance to hens provided one balanced diet. Also, the detrimental effects of high environmental temperature were not overcome by dietary self-selection.

Animals↗

PubMed2001

Variation, selection and evolution of function-valued traits.

We describe an emerging framework for understanding variation, selection and evolution of phenotypic traits that are mathematical functions. We use one specific empirical example--thermal performance curves (TPCs) for growth rates of caterpillars - to demonstrate how models for function-valued traits are natural extensions of more familiar, multivariate models for correlated, quantitative traits. We emphasize three main points. First, because function-valued traits are continuous functions, there are important constraints on their patterns of variation that are not captured by multivariate models. Phenotypic and genetic variation in function-valued traits can be quantified in terms of variance-covariance functions and their associated eigenfunctions: we illustrate how these are estimated as well as their biological interpretations for TPCs. Second, selection on a function-valued trait is itself a function, defined in terms of selection gradient functions. For TPCs, the selection gradient describes how the relationship between an organism's performance and its fitness varies as a function of its temperature. We show how the form of the selection gradient function for TPCs relates to the frequency distribution of environmental states (caterpillar temperatures) during selection. Third, we can predict evolutionary responses of function-valued traits in terms of the genetic variance-covariance and the selection gradient functions. We illustrate how non-linear evolutionary responses of TPCs may occur even when the mean phenotype and the selection gradient are themselves linear functions of temperature. Finally, we discuss some of the methodological and empirical challenges for future studies of the evolution of function-valued traits.

Animals↗

PubMed2007

Polychlorinated biphenyls and -naphthalenes in pine needles and soil from Poland--concentrations and patterns in view of long-term environmental monitoring.

Pine needles were selected as cost effective and easy collectable matrices suitable for long-term monitoring of the lower troposphere pollution with polychlorinated biphenyls and polychlorinated naphthalenes. The fingerprints of PCNs and PCBs in the top layers of agricultural soils were used for determination of point sources of pollution for terrestrial ecosystems. The new idea based on the use of nona- and decachlorinated isomers fingerprint as an additional tool suitable for the identification of potential point sources of pollution with PCBs, seemed to be a capable tool to identify contamination of soil and ambient air related to former manufacturing and the use of highly chlorinated technical PCB preparations.

Air↗