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Results for “Reaction norms”

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At least 19 recordsLinked to original sources

PubMedDate not supplied

Genotypological method of analysis of individual responsiveness of an organism in experiment.

The principle of a genotypological method of analysis of individual responsiveness of an organism in experiment is formulated on the basis of data in the literature and the results of the author's own investigations. The main objective of a genotypological method is the determination of the constitutional typological features of responsiveness and their markers on the basis of similar or different norms of reaction and paratypical factors. It is proposed that individual responsiveness in a population be determined by way of disclosing in individuals the corresponding markers previously established in linear and non-linear animals in experiment, while observing a number of necessary conditions. These markers, capable of playing the role of indicators of a "constitutional typological reaction norm" and also of an individual reaction norm with respect to a concrete agent, are called genotypological markers.

Animals↗

PubMed2026

Maternal and developmental temperature modulate adult response to temperature in Drosophila melanogaster.

Beyond inherited genes and environmentally induced changes in gene expression, phenotypes can also be shaped by parental effects-an effect from a parental phenotype that causes modifications in offspring traits, which cannot be solely explained by the parental or offspring genomes. Such effects may prepare offspring for future environmental conditions and contribute to phenotypic plasticity, including responses to temperature. While temperature-induced plasticity has been extensively studied, the relative contributions of parental versus direct environmental cues remain poorly understood. The fruit fly Drosophila melanogaster is a powerful model for studying physiological and behavioral adaptation to temperature. Flies inhabit environments spanning broad thermal ranges and show evidence of parental effects, such as increased heat tolerance in offspring from warm-reared parents. Here, we exposed mothers to two experimental temperatures and split their broods between the same two temperatures to estimate the relative importance of maternal and developmental effects on adult physiological and developmental responses to temperature. We find that the reaction norms of locomotor activity under gradually increasing temperatures, responses to heat-shock and cold-shock, and fecundity are mostly governed by direct plastic responses to developmental environment. We detected comparatively weak maternal effects in the response to heat-shock, fecundity, and grand-offspring survival where matched environments counteracted the effects of direct offspring experience. We conclude that thermal experience during development is the primary determinant of phenotypic plasticity in D. melanogaster, while maternal experience contributes a small but non-negligible component.

Animals↗

PubMed2025

Repeated evolution of photoperiodic plasticity by different genetic architectures during recurrent colonizations in a butterfly.

In cases of recurrent colonizations of similar habitats from the same base population, it is commonly expected that repeated phenotypic adaptation is caused by parallel changes in genetic variation. However, it is becoming increasingly clear that similar phenotypic variation may also evolve by alternative genetic pathways. Here, we explore the repeated evolution of photoperiodic plasticity for diapause induction across Swedish populations of the speckled wood butterfly, Pararge aegeria. This species has colonized Scandinavia at least twice, and population genomic results show that one of the candidate regions associated with spatial variation in photoperiodism is situated on the Z-chromosome. Here, we assay hybrid crosses between several populations that differ in photoperiodic plasticity for sex-linked inheritance of the photoperiodic reaction norm. We find that while a cross between more distantly related populations from the two different colonization events shows strong sex-dependent inheritance of photoperiodic plasticity, a cross between two more closely related populations within the oldest colonization range shows no such effect. We conclude that the genotype-phenotype map for photoperiodic plasticity varies across these populations and that similar local phenotypic adaptation has evolved during recurrent colonization events by partly non-parallel genetic changes.

Butterflies↗

PubMed1977

[Biological bases of aging].

The author discusses ageing with special regard to evolution processes. Accelaration and retardation of certain ontogenetic phases or the whole ontogenesis have developed during phylogenesis and have been fixed genetically as a special reaction norm. The limitation of life span in highly differentiated organisms after reproduction is perfected has to be considered as one of the preconditions of evolution. Considering the phylogenesis, those hypotheses which interpret ageing as a continuous accumulation of cell damage, are no longer admissable. The different theories of the genetic control for ontogenesis are discussed on the basis of international literature.

Aging↗

PubMedDate not supplied

[Evaluation of the antiorthostatic reactions of the cerebral circulation].

On the basis of experiments on 122 healthy male test subjects the norms of reactions of cerebral circulation to antiorthostatic exposures, basic principles and evaluations of its antiorthostatic tolerance (AOT) were established. The level of AOT was found to increase in acrobats in the course of their training, in test subjects after 30-day head-down tilting, and in space crewmen postflight. This increase can be regarded as an adaptive reaction of cerebral circulation to the excess blood rush to the head both on the Earth and in weightlessness. The similarity of regulatory hemodynamic changes in the above groups shows the possibility and indicates approaches to the ground-based training of cerebral circulation aimed at facilitating and accelerating its adaptation to weightlessness.

Adaptation, Physiological↗

PubMed2026

Deconstructing empirical fitness seascapes across scales of granularity.

The fitness landscape metaphor remains resonant in evolutionary theory and has facilitated the birth of newer concepts, like the fitness seascape, that consider the role of environmental context in shaping the dynamics of evolution. Since its emergence, the seascape has appeared in numerous studies examining how different and fluctuating environments shape evolutionary outcomes. Despite growing interest, we lack comprehensive examinations of how environmental context shapes features of fitness seascapes. In this study, we address this gap by deconstructing empirical fitness seascapes across scales of granularity: loci, locus interactions (epistasis), alleles, trajectories, and entire seascapes. For each, we examine how environmental context influences qualitative and quantitative aspects of seascapes, and find that they change appreciably, with patterns specific to individual systems of study. We also quantify how much each scale varies across environments, and find that certain scales tend to be more sensitive to context than others. In summary, we reflect on the implications of the seascape metaphor for the incorporation of environmental effects into theoretical population genetics, for understanding how the environment shapes evolution in disease systems, and for contemporary bioengineering efforts.

Genetic Fitness↗

PubMedDate not supplied

Functional relationships between genotypes and environments in behavior. Effects of different kinds of early social experience on interstrain fighting in male mice.

Comparisons are made of the interstrain fighting behavior of adult male mice from two inbred strains (ST-albino; CBA-black-agouti), raised in one of three postweaning social situations: 1) isolated from other males, 2) reared with males of the same strains, or 3) reared with males of the opposite strain. Using the fighting behavior of isolated males as a baseline, it is found that each type of early social experience affects the fighting behavior of the males from each of the two inbred strains differently, indicating that the functional relationships between genotype and environment studied in these experiments are nonadditive. The importance of these results in describing the norm of reaction of a behavioral phenotype and in extrapolating data from one experiment to another is discussed.

Aggression↗

PubMedDate not supplied

Investigation of populations of herbaceous plants in natural conditions and under cultivation.

The results of experimental investigations of the morphogenesis of vegetative organs of plants under conditions of cultivation indicated that conclusions about the true composition of populations cannot be drawn from data obtained from descriptions of plants in nature (we have in mind the following characteristics: structure, type and dimensions of shoots, form of leaves, form and dimensions of the root system, etc.). These descriptions make it possible to ascertain only the fact of variability of plants and to characterize specific variance from the norm of reaction to given conditions, which vary for each individual. The true composition of a natural population may be determined by growing plants in an area where there is no competition among them and where all factors are standardized. Only under such conditions is it possible to study the morphogenesis of vegetative organs.

Morphogenesis↗

PubMed1976

[Integrated stimulation test with releasing hormones on healthy men and on patients with various forms of male hypogonadism].

Ninety subjects were examined; 20 healthy males, 20 patients with primary hypogonadism, 30 patients with Klinefelter's syndrome and 20 patients with secondary hypogonadism. The stimulating test with 200 mug LH-RH and 200 mug TTH was carried out tp all subjects examined, applied in two successive o.v. injections. The plasma as regards the levels of TTH, prolactin, FSH, LH, ACTH and STH is investigated every 0,20, 30, 60 and 90 minutes. The levels of tbe mentioned hormones were determined as well as the normal respond reaction. The basic LH and FSH levels are considerabty elevated in patients with primary hypogonadism and Klinefelter's syndrome and the respond reaction to stimulation is normal or diminished. A strict correlation between the number of X chromosomes and the level of FSH and LH was established in the patients with Klinefelter's syndrome. With respect to TTH, the basic, level in patients with primary hypogonadism in normal in 13 patients and pathological deviations were found in 7 patients. A strict correlation between TTH level and the number of X-chromosomes exists, Prolactin level in both groups is decreased. In patients with secondary hypogonadism the basic level of LH and ESH is decreased or at the lower limits of the norm. The respond reaction is absent. Both TTH and prolactin levels are pathologically changed as well as the respond reactions to stimulation depending on the etiology of the primary endocrine distrubance that had led to hypoginadism development.

Adult↗

PubMed1979

[Importance of the work environment for the respiratory system].

In the working process a great number of dusts, gases and smokes affect on the respiratory organs which may lead to fibrogenic, irritative, toxic, cancerogenic or allergic reactions, when the norms of industrial hygiene are not observed. In addition to this come still infective agents. Also communal surroundings, habits of life and medicaments are able to impair the respiratory organ with concurrent noxae. Among the professional diseases which are annually acknowledged about 1,200 (10%) concern the respiratory organ. Apart from the classical professional diseases silicosis and asbestosis unspecific diseases of the respiratory organ, carcinomas and allergoses come into the foreground of interest. The report needs special knowledge in the field of professional medicine and an analysis of the working conditions. The observation of the MAK-values is the prerequisite for the prophylaxis and prevention. For noxae with biologic long-term effects the life-long control of the exposed persons is necessary.

Air Pollutants↗

PubMed1978

The relationship of perceived societal hostility, conformity, and psychological adjustment in homosexual males.

The present study examined the relationship between the perception by homosexual males of positive or negative societal reaction to homosexuality (PSR), their degree of conformity to heterosexual norms, and their degree of psychological adjustment. In this study respondents with high PSR were those who perceived negative societal reaction to homosexuality. Respondents with low PSR were those who perceived positive societal reaction. The study differentiated between the effects of putative societal reaction and actual societal reaction and was based on a three-group sample of homosexual men who (a) were, (b) had been, or (c) had never been heterosexually married. Findings showed that putative societal reaction was a critical variable producing conformity and psychological maladjustment in homosexual males.

Adaptation, Psychological↗

PubMed1977

[Proteinuria and kidney transplantation. A quantitative immunochemical study of 7 protein clearances during the first 50 days following implantation of cadaver kidney].

During the initial 50 days following transplantation of a cadaver kidney into 8 patients, determinations of 7 individual protein clearances were performed twice a week. This, the first posttransplantation investigation of single protein clearances utilizing unconcentrated urine, was made possible by the highly sensitive electroimmunodiffusion method of LAURELL [24]. The following results were obtained: 1. Kidney implantation was immediately followed by glomerulo-tubular proteinuria. In patients exhibiting good transplant tolerance the tubular proteins disappeared from the urine by the 43rd day at the latest; on the other hand, excretion of the glomerular proteins transferrin and albumin continued. In patients without complications the proteinuria was already highly selective by the 7th day (70 degrees). 2. In 5 of 8 patients there was a change in the proteinuria pattern during the rejection crisis: glomerulo-tubular proteinuria occurred three times and glomerular proteinuria twice. In two of these cases there was a change in the selectivity. 3. Patients with good tolerance showed plasma prealbumin levels which increased as a function of the time lapse since transplantation. 4. The plasma concentration of retinol-binding protein did not vary following transplantation and remained at 16.8 +/- 2.8 mg% in patients with uneventful course and at 18.5 +/- 4.9 mg% in patients with transplant rejection reactions, both values being markedly above the norm (4.7 +/- 1.1 mg%, [1 SD]).

Adult↗

PubMed1977

[Electron-cytochemical study of the localization and properties of ATPases in the isolated nuclei of rabbit skeletal muscle under normal conditions and in experimental muscular dystrophy].

The properties and localization of ATPase system in nuclei of skeletal muscle of normal rabbit and of those with experimental muscle dystrophy were studied by electron cytochemistry. The product of cytochemical reaction of ATP hydrolysis, which is a marker of ATPase activity localization in nuclear ultrastructures, was detected on the nuclear membrane, in chromatin and in the nucleolus, ATPase activity in the nuclei was detected in the presence of both, Mg2+ and Ca2+. Addition to the incubation medium, originally containing Mg2+, Na+ and K+, resulted in an increased formation of the product reaction in all the nuclear ultrastructures in both in the norm and under experimental muscle dystrophy. However, specific inhibitor of Mg2+, Na+, K+-ATPase--ouabain--suggests the absence in the nuclei of skeletal muscles of rabbit of transport ATPase working in the "Na-pump" system. The results of experiments with a specific complex of Ca2+--EGTA allow to suppose that Mg2+, Ca2+-ATPase of skeletal muscle nuclei of normal rabbits is localized in the nucleoplasm, whereas Mg2+-ATPase is found on the nuclear membrane. Using EGTA we failed to detected the localization of Mg2+, Ca2+-ATPase in nuclear ultrastructures upon experimental muscular dystrophy.

Adenosine Triphosphatases↗

PubMedDate not supplied

[Kinetic properties of the Ca2+--ATPase in the skeletal muscle sarcolemma of the rabbit normally and in E-avitaminotic dystrophy].

The article deals with values of seeming Michaelis' constants (for ATP) obtained at different temperatures and Michaelis' constants (for Ca ATP) obtained at 30degrees C with pathology and in norm for sarcolemma Ca2+-ATPase. It follows from the analysis of the Ca2+ total concentration effect (the ATP total concentration being constant) on the activation energy of ATP hydrolysis reactions that with pathology sarcolemma possesses, evidently, a greater adsorption affinity to Ca2+ (the enzyme activator) than in norm. The thermoinactivation properties of the enzyme are studied. It is shown that the inactivation coefficient with pathology increases more rapidly with a temperature rise than in norm. It indicates to the fact that the enzyme from the dystrophic muscles is more labile to the heat effect than from the normal ones.

Adenosine Triphosphatases↗

PubMed1977

[Morphometric study of the ultrastructure of cells of the zona fasciculata of the adrenals in rats under stress].

A morphometrical study of cell ultrastructures of zona fasciculata of rat adrenal cortex was performed in norm and after immobilization during 4 or 24 hours. A 4 hour's immobilization (alarm reaction) is characterized by adrenocorticocyte activation: relative volumes of mitochondria and reticulum increase by 1.1 and 1.2 times, resp., and lipid volume decrease by 2.6 times. 24 hours after immobilization (the stage of maximal strain), mitochondrion and reticulum volumes decrease by 1.5 and 1.7 times, resp., compared to the initial ones, and autophagosome volumes increase sharply reaching 11% of the cytoplasm volume, i.e. this is the evidence of degeneration clearly registered morphometrically.

Adrenal Cortex↗

PubMed1977

[Electrophysiological evaluation of the age-related characteristics of the central nervous system in children with spastic cerebral palsy].

As a result of the conducted studies, the authors were able to demonstrate that in children from 4-9 years with cerebral spastic paralysis the potentiated tonic reactions are preserved (the reflex of distention from the gastrocnemius muscle, cervico-tonical reflex to the extremities and reaction of support). The frequency and regularity of alpha-rhythm on the EEG of these children differ significantly from similar ones of normal children of the same age. As the children grow older, the frequency of exaltated tonic reactions decrease and at the same time the frequency and regularity of alpha-rhythms increases, however the differences compared to age norms are preserved. The authors are of the opinion that in older children with infantile cerebral paralysis, despite the retardation of the morpho-functional development of the higher areas of the brain, the degree of cortical maturity is sufficient to inhibit an increased activity of the stem centres regulating the muscular tone.

Adolescent↗

PubMed1978

Sex differences in responsiveness to infants: a developmental study of psychophysiological and behavioral responses.

Sex differences in responsiveness to infants were investigated by comparing physiological responses to infants with overt behavioral reactions. The former were assumed to be more biologically determined than the latter whereas overt behavioral responsiveness was presumed to be more affected by societal norms than were psychophysiological indices. The subjects were boys and girls in middle childhood and early adolescence. Psychophysiological indices showed that children, like parents, responded differentially to infant smiles and cries. As predicted, there were no sex differences on psychophysiological measures of responsiveness to babies. When permitted to interact with a baby, however, girls interacted more and ignored less than boys did. The results suggest that sex differences in overt responsiveness to babies are attributable to societal pressures rather than innate factors. Sex differences appear to wax and wane depending on the salience of sex stereotypy in differing developmental phases.

Adolescent↗

PubMed1979

Abnormal cellular immune responses during acquired zinc deficiency.

The cellular immune response of a 17-year-old decerebrate male with acquired zinc deficiency was studied. He had been fed a commercial formula which contained 7.6 mg zinc per kilogram. His caloric intake had been inadequate as judged by his cachexia. A detailed pretreatment nutritional assessment (five separate observations) which included total serum protein and globulins, albumin, folate, vitamins A, B2, C, ceruloplasmin, and plasma zinc, copper, iron, and total iron binding capacity revealed that the patient was deficient only in zinc and calories. His plasma zinc was 41 +/- 5 microgram/d1 compared with our laboratory norm of 89 +/- 9 microgram/d1 for young adult males. Cellular immunity was assessed by delayed skin reactivity to dinitrochlorobenzene and by in vitro lymphocyte transformation studies. Before zinc therapy the patient rendered a negative skin reaction to dinitrochlorobenzene, and the ability of his lymphocytes to undergo blast transformation in response to mitogen stimulation was significantly depressed with a stimulation index of 4.7 +/- 0.8 as compared with 139.1 +/- 77.3 for controls. Within 3 weeks after zinc therapy (22.7 mg zinc per day) he demonstrated a positive delayed skin reaction to dinitrochlorobenzene and a normal lymphocyte response stimulation index = 205.5 +/- 42.6 versus 199.3 +/- 58.2 for control). In addition, a pretreatment facial seborrhea and a decubitus ulcer rapidly healed.

Adolescent↗