Meiosis in Coprinus. III. Timing of meiotic events in C. lagopus (sensu Buller)

1970 ◽  
Vol 48 (12) ◽  
pp. 2183-2186 ◽  
Author(s):  
N. B. Raju ◽  
B. C. Lu
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Division ◽  
Nuclear Fusion ◽  
Time Sequence ◽  
The Other ◽  
Sequence Study ◽  
Late Diplotene

The close synchrony of meiotic events within the basidiocarp of Coprinus lagopus permits the time sequence study of division stages. It takes about 16 h from the beginning of karyogamy to the completion of meiosis (zygotene to tetrad formation). Nuclear fusion and chromosome pairing occupy about 4 h, pachytene 5 h, diplotene 4 h, and all the other stages including the second meiotic division appear to be very transitory and together occupy less than 3 h. The centrosome divides at late diplotene. The entire second meiotic division takes about 1 hour and different stages overlap a great deal. The four sterigmata are formed after the completion of second division. The basidiospores mature in 8–10 h after the tetrad formation.

Strong effect of PTH (1-34) on regenerating bone: A time sequence study in rats

2000 ◽  
Vol 71 (6) ◽  
pp. 619-624 ◽  
Author(s):  
Ralf Skripitz ◽  
Troels T Andreassen ◽  
Per Aspenberg
Keyword(s):  
Time Sequence ◽  
Sequence Study

Relative choronology: three methods of reconstruction

1976 ◽  
Vol 12 (2) ◽  
pp. 209-258 ◽  
Author(s):  
Matthew Y. Chen
Keyword(s):  
Time Sequence ◽  
The Other ◽  
Historical Records ◽  
Methods Of Reconstruction

In reconstructing protoforms and linguistic histories, many methods can and have been employed with varying degrees of effectiveness (cf. Bonfante, 1945, for a general discussion). For the specific purpose of establishing the time sequence of phonological changes according to which sound systems have evolved, traditionally two procedures have been most frequently followed: one is to sift the historical records for clues to the dates of linguistic innovations, and the other is to infer from the systematic correspondences between protoforms and their modern reflexes the internally motivated order of diachronic rules.

Pattern of X-Y chromosome pairing in the Taiwan vole, Microtus kikuchii

Genome ◽  
2001 ◽  
Vol 44 (1) ◽  
pp. 27-31 ◽  
Author(s):  
K Mekada ◽  
M Harada ◽  
L K Lin ◽  
K Koyasu ◽  
P M Borodin ◽  
...  
Keyword(s):  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Sex Chromosomes ◽  
Meiotic Prophase ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
The Other ◽  
Banding Patterns ◽  
Y Chromosomes

Pairing of X and Y chromosomes at meiotic prophase and the G- and C-banding patterns and nucleolar organizer region (NOR) distribution were analyzed in Microtus kikuchii. M. kikuchii is closely related to M. oeconomus and M. montebelli, karyologically and systematically. The formation of a synaptonemal complex between the X and Y chromosomes at pachytene and end-to-end association at diakinesis – metaphase I are only observed in three species in the genus Microtus; M. kikuchii, M. oeconomus, and M. montebelli. All the other species that have been studied so far have had asynaptic X–Y chromosomes. These data confirm that M. kikuchii, M. oeconomus, and M. montebelli are very closely related, and support the separation of asynaptic and synaptic groups on the phylogenetic tree.Key words: Microtus kikuchii, Microtus phylogeny, karyotype, synaptic sex chromosomes, synaptonemal complex.

scholarly journals Analysis of the Effects of Electrification of the Road Transport Sector on the Possible Penetration of Nuclear Fusion in the Long-Term European Energy Mix

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3634
Author(s):  
Daniele Lerede ◽  
Chiara Bustreo ◽  
Francesco Gracceva ◽  
Yolanda Lechón ◽  
Laura Savoldi
Keyword(s):  
Power Plants ◽  
Nuclear Fusion ◽  
Energy System ◽  
Road Transport ◽  
The Other ◽  
Electricity Production ◽  
Transport Sector ◽  
Consumption Pattern ◽  
Deep Penetration ◽  
The Road

The European Roadmap towards the production of electricity from nuclear fusion foresees the potential availability of nuclear fusion power plants (NFPPs) in the second half of this century. The possible penetration of that technology, typically addressed by using the global energy system EUROFusion TIMES Model (ETM), will depend, among other aspects, on its costs compared to those of the other available technologies for electricity production, and on the future electricity demand. This paper focuses on the ongoing electrification process of the transport sector, with special attention devoted to road transport. A survey on the present and forthcoming technologies, as foreseen by several manufacturers and other models, and an international vehicle database are taken into account to develop the new road transport module, then implemented and harmonized inside ETM. Following three different storylines, the computed results are presented in terms of the evolution of the road transport demand in the next decades, fleet composition and CO 2 emissions. The ETM results are in line with many other studies. On one hand, they highlight, for the European road transport energy consumption pattern, the need for dramatic changes in the transport market, if the most ambitious environmental goals are to be pursued. On the other hand, the results also show that NFPP adoption on a commercial scale could be justified within the current projection of the investment costs, if the deep penetration of electricity in the road transport sector also occurs.

Evolution of European Cockchafers (Melolonthinae: Scarabaeidae: Coleoptera): a morphological, molecular and chromosomal study of intra- and inter-specific variations

2011 ◽  
Vol 101 (3) ◽  
pp. 345-352 ◽  
Author(s):  
T. Giannoulis ◽  
A.-M. Dutrillaux ◽  
Z. Mamuris ◽  
O. Montreuil ◽  
C. Stamatis ◽  
...  
Keyword(s):  
Gene Sequence ◽  
Chromosomal Polymorphism ◽  
Morphological Characters ◽  
The Other ◽  
Ancestral Karyotype ◽  
Intraspecific Polymorphism ◽  
Morphological Variations ◽  
Chromosomal Study ◽  
Sequence Study

AbstractIn cockchafers of the genus Melolontha, there is a marked intraspecific polymorphism for morphological characters, making some specimens of one species resemble another. A cytogenetic and molecular (mitochondrial COI gene sequence) study of typical and atypical forms of M. melolontha and M. hippocastani, captured at the same period and area, was performed. Karyotypes and haplotypes clearly characterize each taxon, placing atypical specimens in one or the other species unambiguously. This formally discards the role of hybridization in phenotypic resemblance, as usually proposed. Karyotypes and haplotypes were compared to those of M. pectoralis and Phyllophaga pleei, a more distantly related Melolonthinae, and some Dynastinae species, to reconstruct their ancestral karyotype. The karyotype of M. melolontha is the most derivative and that of P. pleei the most conserved among the Melolonthinae studied, which fits with the phylogeny established by COI gene analysis. Both karyotypes and COI haplotypes demonstrate the proximity of M. pectoralis and M. melolontha. The karyotype of M. melolontha is polymorphic, without relationship with morphological variations. Finally, the existence of similar morphological variations in different Melolontha species and chromosomal polymorphism in M. melolontha is discussed in relation with a network (reticulated) mode of speciation.

XIV.—The Genetical and Mechanical Properties of the Sex Chromosome. VI. Hexacentrus mundus

1940 ◽  
Vol 60 (2) ◽  
pp. 174-181
Author(s):  
P. C. Koller
Keyword(s):  
Mechanical Properties ◽  
X Chromosome ◽  
Meiotic Division ◽  
Sex Chromosome ◽  
The Other ◽  
Single Sex ◽  
Heterogametic Sex

Cytological studies carried out by McClung (1905, 1914) on various species of Orthoptera have shown that the male is the heterogametic sex. The male has only one X-chromosome, whereas the female has two. During spermatogenesis two kinds of gametes are produced, one with the X-chromosome and the other without it. It was also found that the segregation of the single sex chromosome takes place at first meiotic anaphase. The present paper describes the sex chromosome of the male Hexacentrus mundus Walker, from India. During the meiotic division this chromosome exhibits peculiarities which it is believed have not hitherto been seen in any species of the Orthopteræ.

scholarly journals Regulation of acid phosphatase activity in human promyelocytic leukemic cells induced to differentiate in culture.

1979 ◽  
Vol 83 (2) ◽  
pp. 300-307 ◽  
Author(s):  
A Vorbrodt ◽  
P Meo ◽  
G Rovera
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Smooth Endoplasmic Reticulum ◽  
Leukemic Cell ◽  
Time Sequence ◽  
Leukemic Cells ◽  
Leukemic Cell Line ◽  
Faint Band ◽  
Induction Of Differentiation ◽  
Sequence Study

Induction of differentiation of a human promyelocytic leukemic cell line (HL60) in culture is accompanied by changes in acid phosphatase (Acpase) activity. The increase in activity is less than twofold when the leukemic cells are stimulated by dimethylsulfoxide (DMSO) to differentiate into metamyelocytes and granulocytes but is eightfold when the cells are stimulated by the tumor-promoting agent 12-0-tetradecanoylphorbol 13-acetate (TPA) to differentiate into macrophage-like cells. Five different isozymes of Acpase were separated by acrylamide gel electrophoresis. Isozyme 1, the most anodal isozyme, was found to be present in undifferentiated, DMSO-treated and TPA-treated cells; isozyme 2 was a very faint band observed both in DMSO- and TPA-treated cells, the isoenzymes 3a and 3b were present only in TPA-induced cells; and isozyme 4, the most cathodal isozyme, was present both in TPA- and DMSO-induced cells. A time sequence study on the appearance of the various forms after TPA treatment indicated that the expression of the isozymes is regulated in an uncoordinated fashion. Acpase activity has been shown by ultrastructural cytochemistry to be localized in the entire rough endoplasmic reticulum (RER) and in areas of the smooth endoplasmic reticulum (SER) located near the Golgi complex in differentiating cells but to be extremely weak, if at all detectable, in undifferentiated promyelocytes.

Effect of chromosome 1B, chromosome 6B, and low temperature on the frequency of chromosome pairing at first meiotic metaphase in hexaploid triticale

1983 ◽  
Vol 25 (3) ◽  
pp. 278-282
Author(s):  
Julian B. Thomas ◽  
P. J. Kaltsikes ◽  
S. Shigenaga
Keyword(s):  
Low Temperature ◽  
Common Wheat ◽  
Chromosome Pairing ◽  
Meiotic Metaphase ◽  
The Other ◽  
Hexaploid Triticale ◽  
Other Hand

Chromosome 1B in 'Rosner' and chromosome 6B in line 125 both reduced the frequency with which chromosomes were paired at first meiotic metaphase of hexaploid triticale. On the other hand, chromosome 6B in 'Rosner' and chromosomes 1B and 6B in line 110 had no such effect. The 1B pairing suppressor in 'Rosner' was located on the short arm of the chromosome (1Bs). Between 10 and 30 °C, pairing frequency was quite stable in 'Rosner' triticale in comparison with common wheat, although the level was consistently lower in the triticale. Some reduction of pairing frequency was noted at 10 °C in 'Rosner'. This effect of low temperature did not interact with 1B dosage to cause a disproportionate decrease in pairing frequency when plants with high 1B dosage were grown at 10 °C.

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