Genetic variation for monomer–dimer equilibria of esterase-5 in Drosophila pseudoobscura, Drosophila persimilis, and Drosophila miranda

1984 ◽  
Vol 26 (3) ◽  
pp. 374-381 ◽  
Author(s):  
David R. Townsend ◽  
Rama S. Singh
Keyword(s):  
Electrophoretic Mobility ◽  
Enzyme Stability ◽  
Good Deal ◽  
The Other ◽  
Drosophila Pseudoobscura ◽  
Closely Related Species ◽  
Speciation Event ◽  
Population Polymorphism ◽  
Drosophila Persimilis ◽  
Close Relatives

Esterase-5 is a highly polymorphic enzyme in Drosophila pseudoobscura and its close relatives. Numerous alleles have been identified by employing a number of physicochemical properties of the enzyme (e.g. electrophoretic mobility, enzyme stability, subunit dimerization, and variation in monomer–dimer equilibrium). Variation in the monomer–dimer equilibrium of esterase-5 leads to differences in electrophoretic mobility of monomers produced by dimers all of which have the same mobility. In this report we have used this criterion to study variation within, as well as between, four closely related species: D. pseudoobscura pseudoobscura, D. pseudoobscura bogotana. D. persimilis, and D. miranda. All lines were characterized for esterase-5 monomer and dimer mobility at a number of gel concentrations and the comparison was made by plotting log10 monomer – dimer mobility as a function of gel concentration. No variation was found within D. p. pseudoobscura or D. p. bogotana but some variation (two distinct alleles) did occur in D. persimilis. Drosophila miranda is segregating for two alleles, one of which is fixed in D. pseudoobscura and the other one is common in D. persimilis. Thus it seems that the variation in monomer–dimer equilibrium is a rather conservative criterion and that the variation in D. miranda is a good deal older than the speciation event(s) which gave rise to D. miranda and the lineage leading to D. pseudoobscura and D. persimilis.Key words: esterase-5, Drosophila pseudoobscura, monomer–dimer equilibrium, population, polymorphism, speciation, electrophoresis.

scholarly journals DISTINCTIONS AMONG ALLELIC VARIANTS ASSOCIATED WITH CHROMOSOME 3 INVERSIONS IN DROSOPHILA PSEUDOOBSCURA AND DROSOPHILA PERSIMILIS

Genetics ◽  
1980 ◽  
Vol 96 (3) ◽  
pp. 727-741
Author(s):  
R A Norman ◽  
Satya Prakash
Keyword(s):  
Acid Phosphatase ◽  
Genetic Variants ◽  
Allelic Variation ◽  
The Other ◽  
Drosophila Pseudoobscura ◽  
Chromosome 3 ◽  
Santa Cruz ◽  
Allelic Variants ◽  
The Common ◽  
Drosophila Persimilis

ABSTRACT Efforts were made to discriminate new genetic variants among electrophoretic alleles that are associated with chromosome 3 inversions of Drosophila pseudoobscura and D. persimilis. Apparent genetic similarities for electrophoretic alleles between these two species and among the common inversions they carry were reexamined by altering gel concentration and buffer pH. At the amylase locus, the 1.09 electrophoretic allele could be further separated into two allelic classes that differentiated the WT and KL arrangements. Similarly, the 0.84 electrophoretic allele was divided into two allelic classes, one characteristic of the Santa Cruz phylad arrangements, TL and SC, and the other found in strains of the Standard phylad arrangements and CH. Uncommon amylase alleles proved to be different alleles in the two species. No new allelic variants, however, could be found among strains with the amylase 1.00 allele, the commonest allele in the Standard phylad of both species. No major new allelic variation was detected for acid phosphatase-3 and larval protein-10 that revealed any further differentiation among species or inversions. Variation at all three loci in strains of the Bogota population remained genetically similar to variation in strains of mainland D. pseudoobscura.

scholarly journals GENIC HETEROGENEITY AT TWO ALCOHOL DEHYDROGENASE LOCI IN DROSOPHILA PSEUDOOBSCURA AND DROSOPHILA PERSIMILIS

Genetics ◽  
1977 ◽  
Vol 87 (2) ◽  
pp. 285-304
Author(s):  
Jerry A Coyne ◽  
Alexander A Felton
Keyword(s):  
Alcohol Dehydrogenase ◽  
Sibling Species ◽  
Genetic Divergence ◽  
Xanthine Dehydrogenase ◽  
The Other ◽  
Drosophila Pseudoobscura ◽  
Main Body ◽  
Striking Increase ◽  
Drosophila Persimilis ◽  
Octanol Dehydrogenase

ABSTRACT A sequential electrophoretic survey of the second chromosome loci, alcohol dehydrogenase-6 (Adh-6) and octanol dehydrogenase (Odh), was performed on 147 isochromosomal lines of Drosophila pseudoobscura and 60 lines of its sibling species, D. persimilis. Gels run with a variety of acrylamide concentrations and buffer pH's revealed the presence of 18 alleles of Adh-6 in the two species, where only eight had been previously detected by conventional electrophoretic methods. Only two alleles were added with our techniques to the previous total of nine in both species at the largely monomorphic Odh locus. Both enzymes show a predominance of one allele, with the other variants being fairly rare. There was no evidence of increased genetic divergence between the two species, but we found a striking increase in differentiation of Adh-6 alleles between the main body of D. pseudoobscura populations and the conspecific isolate from Bogotá, Colombia. These results are compared with our previous surveys of xanthine dehydrogenase in these species and discussed in reference to theories of genic polymorphism.

scholarly journals AN EXPERIMENTAL INVESTIGATION OF THE UNIT CHARGE MODEL OF PROTEIN POLYMORPHISM AND ITS RELATION TO THE ESTERASE-5 LOCUS OF DROSOPHILA PSEUDOOBSCURA, DROSOPHILA PERSIMILIS, AND DROSOPHILA MIRANDA

Genetics ◽  
1977 ◽  
Vol 87 (4) ◽  
pp. 717-742
Author(s):  
Gary Cobbs ◽  
Satya Prakash
Keyword(s):  
Small Molecules ◽  
Electrophoretic Mobility ◽  
Drosophila Pseudoobscura ◽  
Average Effect ◽  
Mobility Data ◽  
Step Model ◽  
Charge Model ◽  
Drosophila Persimilis ◽  
The Relationship ◽  
Charge Change

ABSTRACT The relationship between charge changes and electrophoretic mobility changes is investigated experimentally. The charge of several proteins is altered by reaction with small molecules of known structure and the change in electrophoretic mobility is measured. The method of Ferguson plots is used to separate charge and shape components of mobility differences. The average effect of an amino acid charge change on the mobility of the esterase-51.00 allele of Drosophila pseudoobscura is estimated to be 0.046. This estimate is then used to apply the step model of Ohta and Kimura (1973) to electrophoretic mobility data for the esterase-5 locus of D. pseudoobscura and D. miranda. The variation in electrophoretic mobility at this locus was found to be in agreement with the predictions of the step model.

scholarly journals VARIATION IN BIOCHEMICAL PROPERTIES OF ALLOZYMES OF XANTHINE DEHYDROGENASE IN DROSOPHILA PSEUDOOBSCURA

Genetics ◽  
1980 ◽  
Vol 96 (4) ◽  
pp. 927-938
Author(s):  
David R Wilcox ◽  
Satya Prakash
Keyword(s):  
Substrate Specificity ◽  
Binding Affinity ◽  
Electrophoretic Mobility ◽  
Significant Variation ◽  
Xanthine Dehydrogenase ◽  
Biochemical Properties ◽  
Variant Allele ◽  
Drosophila Pseudoobscura ◽  
Mesa Verde

ABSTRACT Twenty-six D. pseudoobscura strains isogenic for xanthine dehydrogenase alleles from Mesa Verde, Colorado, were tested for differences in the biochemical properties of different allelic forms of xanthine dehydrogenase. No significant differences in binding affinity (Km) or substrate specificity of the enzyme were found. Significant variation among strains, in activity (V  max) and among electromorphs, as well as among strains, in thermolability was found. For the few strains tested, the activity and thermolability differences were shown to co-segregate with the electrophoretic mobility of the variant allele.

Pimpinella ibradiensis (Apiaceae), an unusual new species from Turkey

Phytotaxa ◽  
2015 ◽  
Vol 217 (2) ◽  
pp. 164 ◽  
Author(s):  
İlker Çinbilgel ◽  
özkan Eren ◽  
Hayri Duman ◽  
Mustafa Gökceoğlu
Keyword(s):  
New Species ◽  
Geographical Distribution ◽  
Related Species ◽  
Conservation Status ◽  
Identification Key ◽  
The Other ◽  
Site Conditions ◽  
Closely Related Species

Pimpinella ibradiensis, an unusual new species found in the Toka Yayla (İbradı, Antalya) in southern Anatolia, is described and illustrated. Site conditions, synecology and conservation status of P. ibradiensis are considered. In light of the comparison with the other closely related four species, namely P. nephrophylla, P. flabellifolia, P. sintenisii and P. paucidentata, its similarity within the genus are discussed. P. ibradiensis is easly distinguished from its relatives by its white petals, presence of bracts and bracteoles, larger fruits (4–5.5 × 1–2 mm), and having serrulate basal leaves with 60–95 strongly cartilaginous teeth along margins. The geographical distribution of P. ibradiensis and closely related species are mapped and the identification key of those species is updated.

Notes on the Writing of Scientific English for Japanese Physicists

2014 ◽  
Vol 03 (01) ◽  
pp. 39-53
Author(s):  
Anthony J. Leggett
Keyword(s):  
Good Deal ◽  
Mental Effort ◽  
The Other ◽  
Simple Rule ◽  
Major Point ◽  
Sentence Construction ◽  
Wear And Tear ◽  
Guiding Principles ◽  
Elegant Form ◽  
Form Of Expression

The main guiding principles I have used are the following. First, it is much more important that the English written by Japanese authors be clear and easily readable than that it be elegant. Therefore, in a situation where there is a choice between an elegant form of expression which, however, may easily lead to confusion if misused and a less elegant but practically "foolproof" one, I have never hesitated to recommend the latter. Secondly, the importance of avoiding a mistake is roughly proportional to the amount of misunderstanding it may entail and/or the amount of psychological "wear and tear" it may cause on the reader's nerves. Accordingly, I have spent a good deal of space on "macroscopic" points like sentence construction, and proportionately less on "microscopic" ones like the correct use of "a" and "the"; prepositions, which most Japanese writers seem to consider a major point of difficulty in writing English, I have scarcely mentioned, not only because this is the sort of point for which one can easily refer to dictionaries but because I believe the reader can usually correct any mistakes for himself with very little mental effort. Thirdly, the usefulness of a set of notes such as this is much reduced if the rules given become too complicated. Therefore, rather than give a complicated set of rules which would ensure correctness 100% of the time, I have often preferred to give a simple rule which will be right 95% of the time, provided that in the other 5% of cases, it is unlikely to lead to confusion. I do not claim that anyone who tries to follow the advice given here will write beautiful or even invariably correct English; but I hope that what he writes will be clear and readable and that any mistakes he does make will be minor ones.

Education and Learning at a Medieval English Cathedral: Exeter 1380–1548

1981 ◽  
Vol 32 (3) ◽  
pp. 265-283 ◽  
Author(s):  
Nicholas Orme
Keyword(s):  
Sixteenth Century ◽  
Good Deal ◽  
The Other ◽  
Educational Institutions ◽  
Medieval England ◽  
Literary Education ◽  
Other Hand ◽  
The People ◽  
The Impact

During the last hundred years our knowledge of the educational institutions of medieval England has steadily increased, both of schools and universities. We know a good deal about what they taught, how they were organised and where they were sited. The next stage is to identify their relationship with the society which they existed to serve. Whom did they train, to what standards and for what ends? These questions pose problems. They cannot be answered from the constitutional and curricular records which tell us about the structure of educational institutions. Instead, they require a knowledge of the people—the pupils and scholars—who went to the medieval schools and universities. We need to recover their names, to compile their biographies and thereby to establish their origins, careers and attainments. If this can be done on a large enough scale, the impact of education on society will become clearer. In the case of the universities, the materials for this task are available and well known. Thanks to the late Dr A. B. Emden, most of the surviving names of the alumni of Oxford and Cambridge have been collected and published, together with a great many biographical records about them. For the schools, on the other hand, where most boys had their literary education if they had one at all, such data are not available. Except for Winchester and Eton, we do not possess lists of the pupils of schools until the middle of the sixteenth century, and there is no way to remedy the deficiency.

Private property, public access and occupiers’ liability

Legal Studies ◽  
1995 ◽  
Vol 15 (3) ◽  
pp. 335-355
Author(s):  
FR Barker ◽  
NDM Parry
Keyword(s):  
Legal System ◽  
Private Property ◽  
Good Deal ◽  
Public Access ◽  
The Other ◽  
Legal Responsibility ◽  
Policy Preference ◽  
Duty Of Care ◽  
Liability Rules ◽  
Legal Rules

There is nothing new about legal rules which provide that a person who is in control of land owes a duty of care to entrants thereto. These occupiers’ liability rules are often seen as something primarily to do with tort, but their content and substance are also likely to reveal a good deal about the ‘property policy’ of the legal system in question, in the sense that they will indicate the respective weight and importance attachkd to various kinds of competing claim over land. A legal system containing rules that restrict the circumstances in which those with individual, controlling claims over land owe a duty of care to other persons entering that land would appear to indicate a policy preference for supporting and protecting ‘private property’ claims to land above others. On the other hand, a system which imposes on those controlling land a greater degree of legal responsibility for persons entering thereon may be one based on a policy of recognising, protecting and supporting a range of claims in land beyond those of a narrow, private nature.

Byzantine Scyphate Bronze coinage in Greece

1961 ◽  
Vol 56 ◽  
pp. 42-63 ◽  
Author(s):  
D. M. Metcalf
Keyword(s):  
Thirteenth Century ◽  
Twelfth Century ◽  
Good Deal ◽  
The Other ◽  
Purchasing Power ◽  
Byzantine Empire ◽  
Market Place ◽  
Fourth Crusade ◽  
Unusual Form

The Byzantine coinage in the twelfth century was of three kinds. There were gold nomismata, with a purchasing power which must have been a good deal greater than that of a present-day five-pound note, and also nomismata of ‘pale gold’—gold alloyed with silver—of lower value; at the other extreme there were bronze coins, smaller than a modern farthing, which were the coinage of the market-place; intermediate, but still of low value, there were coins about the size of a halfpenny, normally made of copper lightly washed with silver. The silvered bronze and the gold were not flat, as are most coins, but saucer-shaped. The reason for their unusual form is not known. Numismatists describe them as scyphate, and refer to the middle denomination in the later Byzantine system of coinage as Scyphate Bronze, to distinguish it from the petty bronze coinage. Scyphate Bronze was first struck under Alexius I (1081–1118). Substantive issues were made by John II (1118–43), and such coinage became extremely plentiful under Manuel I (1143–80) and his successors Isaac II (1185–95) and Alexius III (1195–1203). After the capture of Constantinople in the course of the Fourth Crusade, the successor-states to the Byzantine Empire at Nicaea, Salonica, and in Epirus continued to issue scyphate bronze coinage, although in much smaller quantities, until after the middle of the thirteenth century.

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