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1

A cytochemical study on 'nuage' accumulations in primordial germ cells of Tetrodontophora bielanensis (Insecta, Collembola).

100%
Klag J., Ostachowska-Gasior A.
Folia Biologica
|
1997
|
vol. 45
15-20
EN
In the cytoplasm of primordial germ cells (PGCs) of Tetrodontophora bielanensis accumulations of nuage occurred. Before colonization of the gonads it had a fuzzy appearance (fibrous nuage), while after the PGCs had entered the gonads, the nucleolus-like bodies (granular nuage) were extruded from the cell nucleus, joined the fibrous nuage and formed the 'complex nuage'. After the application of the preferential RNA staining in the PGCs of T. bielanensis the fibrous nuage became completely bleached while the granular part remained unchanged. The fibrous nuage behaved exactly like DNA in the nucleus. To test for the presence of DNA in the nuage the DNAze and for the presence of RNA the RNAze digestions were applied. DNA was not found in the fibrous nuage nor in the complex nuage. However, the granular part of the complex nuage appeared to contain RNA. RNA.
2

Development of terminal filaments and ovariole envelopes in Thermobia domestica (Insecta, Zygentoma) larvae

100%
Kisiel E., Klag J.
Folia Biologica
|
2001
|
vol. 49
|
issue 3-4
199-204
EN
The 3rd instar female larvae of Thermobia domestica have five pairs of gonad primordia, each enclosed within a basal lamina (tunica propria). At the end of the 3rd instar some somatic cells scattered on the outer surface of the lamina are seen. During the 4th larval instar the gonad primordia start to form the ovarioles. Each ovariole is elongated and polarized, having anterior and posterior ends. The anterior group of outer somatic cells proliferate to form the terminal filament. At the 6th larval stage the ovarioles are already formed. The terminal filament is separated from the germarium by a thick basal lamina (transverse septum). There are three types of cell building the terminal filament. 1/ Basal cells with numerous finger ? like projections; 2/ Cells with electron lucent cytoplasm and large nuclei, and 3/ Cells with darker cytoplasm containing bundles of fibers and more compact nuclei. The outer surface of the filament is covered by a thick, fibrous basal lamina. The somatic cells that in the previous stages were scattered on the tunica propria as distinct cells, in the 6th larval stage form a cellular envelope (tunica externa). This envelope is formed by a layer of flat cells, and contains numerous tracheae.
3

Do germ-line cells in Allacma fusca (Insecta, Collembola, Symphypleona) have a higher metabolic rate than somatic cells

81%
Swiatek P., Klag J., Romek M.
Folia Biologica
|
2001
|
vol. 49
|
issue 1-2
85-90
EN
Stereological analysis of the ultrastructure of primordial germ cells (PGCs) and the somatic (ectoderm) cells in two developmental stages of embryos and freshly hatched juveniles of Allacma fusca have shown great differences in mitochondria volume density (vd) between the two types of cells. In younger embryos (migration phase of the PGCs) the vd of mitochondria in the cytoplasm of the PGCs is 74.64% higher than in the ectoderm cells. In older embryos, (PGCs in the gonads) the vd of mitochondria is 123% higher than the corresponding value for the somatic cells cytoplasm. In the juvenile the vd of mitochondria in the ectoderm cells grows twice but is still only 2/3 of the value for the PGCs. On the basis of papers describing a direct relationship between stereological and physiological results the authors conclude that the metabolism of the primordial germ cells during embryonic development of Allacma fusca is much higher than that of the somatic ones. If the above conclusion is correct, the results presented here confirm the ?disposable soma theory? (Kirkwood & Holliday 1979).
4

Karyomere formation in cleaving eggs of Tetradontophora bielanensis (Collembola)

81%
Klag J., Jura C., Krzysztofowicz A., Kisiel E.
Folia Biologica
|
1995
|
vol. 43
|
issue 1-2
61-67
EN
The term "karyomere"designates a p[articular kind oforganization of the telophase nucleus, in which each individual chromosome is surrounded by a typical nuclear envelope, thus representing a small nuclear structure.In T.bielenensis they are formed during firts prophase and subsequently change into chromosomes making a metaphase plate.Each metaphase chromosome is completly enclosed by a double envelope, similar to a nuclear one but devoid of nuclear pores.The only place on the chromosome where the envelope is not complete is the region of the kinetochore.Anaphase starts with the division of the chromosome into chromatids and subsequent decondensation of the latter.During anaphase, te process of decondensation of the chromatids starts at the leading ends of each chromatid and hence, they acquire a tennis racket-like appearance.As a result, on the spindle poles two groups of the chromosome vesicles or karyomeres are gethered.Each karyomere has the appearance of a typical nucleus enclosed by a double envelope pierced by nucleus pores filed with nucleoplasm containing patches ofchromatin.It is suggested that karyomeres are formed only in species with a large amount of chromatin in their nuclei.
5

Predetermination of cytokinesis and transition from holoblastic to partial superficial cleavage in early embryonic development of Tetrodontophora bielanensis (Collembola)

81%
Klag J., Krzysztofowicz A., Jura C., Kisiel E.
Folia Biologica
|
2000
|
vol. 48
|
issue 3-4
137-142
EN
In the T. bielanensis embryo, only karyokinesis occurs during the first cleavage division, and a two-nuclear syncytial embryo forms. Then, two cytoplasmic concentrations in the form of elongated rolls perpendicular to each other develop below the periplasm at the animal pole of the egg. The second cleavage division is also associated with karyokineses only. After the embryo reaches the four-nuclear stage, cytokineses occur at its animal pole, and two cleavage furrows perpendicular to each other develop in the periplasm above the cytoplasmic concentrations. The cell membranes forming within the furrows do not invade the cytoplasmic concentrations, but their growing tips push them into the egg interior, where they merge and form the central cytoplasmic concentration. The developing cell membranes do not invade the central cytoplasm; they band and grow above its surface. Four pyramidal blastomeres form as a result of this. The eight-blastomere embryo forms through both karyokinesis and cytokinesis, but the growing cell membranes now band below the previous ones and cut off anucleate parts of the mother blastomeres, which fuse with the central cytoplasm. Thus, during this phase of development the transition from holoblastic to partial superficial cleavage is initiated. Morphological analysis suggests that the formation of the first two cytokineses is predetermined by and depends on factors connected with the animal pole periplasm. It also suggests that the central cytoplasm constitutes the morphological field, inducing the transition from holoblastic to partial superficial cleavage.
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