Lemna minor is a small aquatic polyploid angiosperm which reproduces apomictically and has a worl... more Lemna minor is a small aquatic polyploid angiosperm which reproduces apomictically and has a worldwide distribution. This study was vmdertaken to characterize the extent and nature of phenotypic variability. The techniques of starch gel electrophoresis were used in this investigation and. MDH phenotypes of several populations from Ontario, USA and Africa were examined and compared. Heat stability, molecular weight and cell fractionation analyses were also done to identify locus specific MDH bands. The results of the population surveys suggest that there is little genetic variability present both within and between Lemna minor/Lemna turionifera . Evidence of correlation of physiological and seasonal variation patterns was found.
Plant Systematics and Evolution - PLANT SYST EVOL, 1986
The purpose of this paper is to produce a classification of theHordeum murinum complex. Using an ... more The purpose of this paper is to produce a classification of theHordeum murinum complex. Using an experimental design to account for the environmental component of the phenotypic variation, material from sources throughout the old-world range ofH. murinum was grown in a common environment. Eight morphological characters were measured on the resulting triplets (i.e., the central and lateral florets, glumes and rachis internode). Clustering, variance and discriminants analyses of these data suggest that there are three distinct groups. This classification is then examined for consistency with hypotheses obtained from the work of other researchers and discussed in light of the known biology of the plants. An identification key to members of the complex using the triplet characters is provided.
Journal of Pharmacology and Experimental Therapeutics, 2003
Chromosomal loci containing genes affecting antinociceptive sensitivity to morphine have been ide... more Chromosomal loci containing genes affecting antinociceptive sensitivity to morphine have been identified, but virtually nothing is known about the genetic mediation of sensitivity to overthe-counter analgesics. Such knowledge would be of great clinical interest, as prodigious interindividual variability has been noted in the efficacy of these ubiquitously used drugs. In the present study, we assessed heritability and genetic correlations among three over-the-counter analgesics in mice of 12 inbred mouse strains on the 0.9% acetic acid (i.p.) writhing test. Analgesics included the centrally acting analgesic, acetaminophen (150 mg/kg, s.c.), and the nonsteroidal anti-inflammatory drugs (NSAIDs), indomethacin (40 mg/kg, s.c.) and lysine-acetylsalicylic acid (800 mg/kg, s.c.). Significant strain differences in sensitivity to each of the drugs were observed, with narrowsense heritability estimates ranging from 23 to 45%. Similar strains were sensitive and resistant, respectively, to the two NSAIDs (r s ϭ 0.64). In contrast, a completely different pattern of sensitivities was observed for acetaminophen, implying genetic dissociation (r s ϭ 0.29 and 0.02) compared with the NSAIDs. Additional experiments were performed on two strains, C57BL/6 and DBA/2, with extreme sensitivities to acetaminophen. Plasma acetaminophen levels in these strains were not significantly different during the time of antinociception assessment, suggesting the existence of genetic factors affecting acetaminophen pharmacodynamics rather than pharmacokinetics.
Activity changes of three enzymes (ADH, ODH and AOX) of Drosophila melanogaster were followed und... more Activity changes of three enzymes (ADH, ODH and AOX) of Drosophila melanogaster were followed under different environmental conditions. The influences of ethanol, starvation (no carbohydrates in the medium) and ethanol stress during starvation were studied at both 18 and 26°C. Two strains that were monomorphic for different alleles at the Odh and Aldox loci but otherwise identical were used. The investigated environmental conditions affected ADH induction by exogenous ethanol differently in the two strains. The different allozymes of ODH and AOX also responded differently to the treatments. We observed that the sucrose content of the medium on which ethanol exposure took place and the temperature strongly affected the responses within any single strain. Correlations were estimated among the three enzymes in the larval and adult stages of each strain separately. At both temperatures, differences between strains were observed in the patterns of associations of the response variables, in the larval, but not in the adult stages.
The size of a seed is known to affect the fitness of the plant growing from it; larger seeds ofte... more The size of a seed is known to affect the fitness of the plant growing from it; larger seeds often have the higher fitnesses. Based on the assumption that most seed size variation will be found among genotypes, reductions in the variance of seed size, due to selection towards seeds of similar and larger sizes have been predicted, but unfortunately, not observed. Many plant species produce seeds which vary in size due to their position in the infiorescence or fruit. I thus wanted to see if the variation in seed size within a plant created variation in fitness and if so, whether this might explain why the expected reduction in variance is not observed. Pairs of seeds from the selffertilizing Hordeum vulgare ssp. spontaneum, sharing maternal and paternal genotype, maternal environment and growth environment but differing in the amount of endosperm available to the embryo, were used. Initial seed size affected time of germination, seedling growth rate and the number of seeds produced. There were, however, no differences in the means of the sizes of seed produced by genetically identical individuals, which can be explained if the position effects are regenerated by seeds of different sizes. It is proposed that it is not a particular seed size which characterises a genotype but a particular distribution of sizes. Position effects are the agents creating the size distributions which ensure that seed size and fitness variation is produced every generation. Evidence is presented which suggests that variation in the expression of position effects exists and may be available to selection. The evolutionary role of this variation is considered in light of current models.
Second instar larvae of Drosophila melanogaster were exposed to exogenous alcohol, which is known... more Second instar larvae of Drosophila melanogaster were exposed to exogenous alcohol, which is known to influence the activities of several enzymes. In this study, the activity changes were followed in four enzymes (ADH, ODH, aGPDH and AOX) during ethanol exposure and compared in three inbred lines that had different allelic combinations at the Odh and Aldox loci. The results indicate that the Odh-Aldox region of the third chromosome may alter the general response to ethanol. The activity of ADH increased considerably in two strains in the larval stages in the presence of alcohol; nevertheless, strain 1, with the Odhs-AldoxF allelic combination, showed a delay in the ADH induction compared to strain 2, which had the OdhF-AldoxS combination. In strain 3 (OdhS*-AldoxS) larvae, ADH induction by environmental ethanol was not detected. Moreover, the activities of aGPDH and AOX in strains 2 and 3 were not affected by ethanol. In contrast, the activities of all four enzymes in strain I changed after exposure to ethanol.
PHCSENYE, K., LEFKOVITCH, P., GII.ES, B. E. and SAURA, A. 1994. Does Drosophilu ~nelunoguster use... more PHCSENYE, K., LEFKOVITCH, P., GII.ES, B. E. and SAURA, A. 1994. Does Drosophilu ~nelunoguster use ethanol as an energy source during starvation? ~ Hereditas 121: 225S236. Lund, Sweden.
Lemna minor is a small aquatic polyploid angiosperm which reproduces apomictically and has a worl... more Lemna minor is a small aquatic polyploid angiosperm which reproduces apomictically and has a worldwide distribution. This study was vmdertaken to characterize the extent and nature of phenotypic variability. The techniques of starch gel electrophoresis were used in this investigation and. MDH phenotypes of several populations from Ontario, USA and Africa were examined and compared. Heat stability, molecular weight and cell fractionation analyses were also done to identify locus specific MDH bands. The results of the population surveys suggest that there is little genetic variability present both within and between Lemna minor/Lemna turionifera . Evidence of correlation of physiological and seasonal variation patterns was found.
Plant Systematics and Evolution - PLANT SYST EVOL, 1986
The purpose of this paper is to produce a classification of theHordeum murinum complex. Using an ... more The purpose of this paper is to produce a classification of theHordeum murinum complex. Using an experimental design to account for the environmental component of the phenotypic variation, material from sources throughout the old-world range ofH. murinum was grown in a common environment. Eight morphological characters were measured on the resulting triplets (i.e., the central and lateral florets, glumes and rachis internode). Clustering, variance and discriminants analyses of these data suggest that there are three distinct groups. This classification is then examined for consistency with hypotheses obtained from the work of other researchers and discussed in light of the known biology of the plants. An identification key to members of the complex using the triplet characters is provided.
Journal of Pharmacology and Experimental Therapeutics, 2003
Chromosomal loci containing genes affecting antinociceptive sensitivity to morphine have been ide... more Chromosomal loci containing genes affecting antinociceptive sensitivity to morphine have been identified, but virtually nothing is known about the genetic mediation of sensitivity to overthe-counter analgesics. Such knowledge would be of great clinical interest, as prodigious interindividual variability has been noted in the efficacy of these ubiquitously used drugs. In the present study, we assessed heritability and genetic correlations among three over-the-counter analgesics in mice of 12 inbred mouse strains on the 0.9% acetic acid (i.p.) writhing test. Analgesics included the centrally acting analgesic, acetaminophen (150 mg/kg, s.c.), and the nonsteroidal anti-inflammatory drugs (NSAIDs), indomethacin (40 mg/kg, s.c.) and lysine-acetylsalicylic acid (800 mg/kg, s.c.). Significant strain differences in sensitivity to each of the drugs were observed, with narrowsense heritability estimates ranging from 23 to 45%. Similar strains were sensitive and resistant, respectively, to the two NSAIDs (r s ϭ 0.64). In contrast, a completely different pattern of sensitivities was observed for acetaminophen, implying genetic dissociation (r s ϭ 0.29 and 0.02) compared with the NSAIDs. Additional experiments were performed on two strains, C57BL/6 and DBA/2, with extreme sensitivities to acetaminophen. Plasma acetaminophen levels in these strains were not significantly different during the time of antinociception assessment, suggesting the existence of genetic factors affecting acetaminophen pharmacodynamics rather than pharmacokinetics.
Activity changes of three enzymes (ADH, ODH and AOX) of Drosophila melanogaster were followed und... more Activity changes of three enzymes (ADH, ODH and AOX) of Drosophila melanogaster were followed under different environmental conditions. The influences of ethanol, starvation (no carbohydrates in the medium) and ethanol stress during starvation were studied at both 18 and 26°C. Two strains that were monomorphic for different alleles at the Odh and Aldox loci but otherwise identical were used. The investigated environmental conditions affected ADH induction by exogenous ethanol differently in the two strains. The different allozymes of ODH and AOX also responded differently to the treatments. We observed that the sucrose content of the medium on which ethanol exposure took place and the temperature strongly affected the responses within any single strain. Correlations were estimated among the three enzymes in the larval and adult stages of each strain separately. At both temperatures, differences between strains were observed in the patterns of associations of the response variables, in the larval, but not in the adult stages.
The size of a seed is known to affect the fitness of the plant growing from it; larger seeds ofte... more The size of a seed is known to affect the fitness of the plant growing from it; larger seeds often have the higher fitnesses. Based on the assumption that most seed size variation will be found among genotypes, reductions in the variance of seed size, due to selection towards seeds of similar and larger sizes have been predicted, but unfortunately, not observed. Many plant species produce seeds which vary in size due to their position in the infiorescence or fruit. I thus wanted to see if the variation in seed size within a plant created variation in fitness and if so, whether this might explain why the expected reduction in variance is not observed. Pairs of seeds from the selffertilizing Hordeum vulgare ssp. spontaneum, sharing maternal and paternal genotype, maternal environment and growth environment but differing in the amount of endosperm available to the embryo, were used. Initial seed size affected time of germination, seedling growth rate and the number of seeds produced. There were, however, no differences in the means of the sizes of seed produced by genetically identical individuals, which can be explained if the position effects are regenerated by seeds of different sizes. It is proposed that it is not a particular seed size which characterises a genotype but a particular distribution of sizes. Position effects are the agents creating the size distributions which ensure that seed size and fitness variation is produced every generation. Evidence is presented which suggests that variation in the expression of position effects exists and may be available to selection. The evolutionary role of this variation is considered in light of current models.
Second instar larvae of Drosophila melanogaster were exposed to exogenous alcohol, which is known... more Second instar larvae of Drosophila melanogaster were exposed to exogenous alcohol, which is known to influence the activities of several enzymes. In this study, the activity changes were followed in four enzymes (ADH, ODH, aGPDH and AOX) during ethanol exposure and compared in three inbred lines that had different allelic combinations at the Odh and Aldox loci. The results indicate that the Odh-Aldox region of the third chromosome may alter the general response to ethanol. The activity of ADH increased considerably in two strains in the larval stages in the presence of alcohol; nevertheless, strain 1, with the Odhs-AldoxF allelic combination, showed a delay in the ADH induction compared to strain 2, which had the OdhF-AldoxS combination. In strain 3 (OdhS*-AldoxS) larvae, ADH induction by environmental ethanol was not detected. Moreover, the activities of aGPDH and AOX in strains 2 and 3 were not affected by ethanol. In contrast, the activities of all four enzymes in strain I changed after exposure to ethanol.
PHCSENYE, K., LEFKOVITCH, P., GII.ES, B. E. and SAURA, A. 1994. Does Drosophilu ~nelunoguster use... more PHCSENYE, K., LEFKOVITCH, P., GII.ES, B. E. and SAURA, A. 1994. Does Drosophilu ~nelunoguster use ethanol as an energy source during starvation? ~ Hereditas 121: 225S236. Lund, Sweden.
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