Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (Tetranychidae, trombidiformes). I: Meiosis in eggs

  title={Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (Tetranychidae, trombidiformes). I: Meiosis in eggs},
  author={C. C. M. Feiertag-Koppen},
Meiosis in eggs of Tetranychus urticae Koch is described. The two maturation divisions result in (a) a haploid female pronucleus consisting of three karyomeres; — (b) a divided first polar body in which the chromosomes change into karyomeres; — (c) a second polar body, entering a new mitosis which is blocked in metaphase. Irradiation of adult females produced chromosome fragments in the meiotic divisions. The fragments behave as intact chromosomes which proves that during meiosis a diffuse… 
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Cytological studies of the two-spotted spider mite Tetranychus urticae Koch (tetranychidae, trombidiformes) II. Meiosis in growing oocytes

The morphology and behaviour of the holokinetic chromosomes of Tetranychus urticae Koch were studied in maturing oocytes from diplotene up to and including metaphase and it was argued that chiasmata terminalise towards both ends of the dyads and that each dyad contains two sister chromatids.

Some remarks on the cytogenetics of oribatid mites

The behaviour of the meiotic segregations of the parthenogenetic oribatid mite Archegozetes longisetosus Aoki were investigated in maturing oocytes and it is believed to have evidence for an inverted meiotic sequence.

Ultrastructure of holokinetic mitotic chromosomes and interphase nuclei of Tetranychus urticae Koch (Acari, Tetranychidae) in relation to loss and missegregation of induced fragments

From morphologic data, the fate of induced chromosome fragments, described in earlier papers, is surmised to depend on events in interphase as well as in mitosis.

Holocentromere identity: from the typical mitotic linear structure to the great plasticity of meiotic holocentromeres

Recent and former findings about centromere/kinetochore adaptations shown by holocentric organisms during mitosis and meiosis are summarized and how these adaptations are related to the type of meiosis found are discussed.

Specialization in the behaviour of chromosomes on the meiotic spindle

Arguments are presented for the hypothesis that the monokinetic chromosomes are nothing but the end point in the same gradient and do not form a fundamentally different category.

Mass Production of Predatory Mites and Their Efficacy for Controlling Pests

This chapter discussed the rearing method on various diets referring to the advantages, the cost and benefit as well as the abundance of these predators and the possibility of their application and success, especially in Egypt.



Cytological evidence for holocentric chromosomes of the silkworms, Bombyx mori and B. mandarina, (Bombycidae, Lepidoptera)

The nature of the centromere and the orientation in meiosis of silkworm chromosomes were investigated using the trivalent of the F1 hybrid between the wild and domestic silkworm and X-ray-induced

Experimental demonstration of holokinetic chromosomes, and of differential “radiosensitivity” during oogenesis, in the grass mite, Siteroptes graminum (Reuter)

In the few cases with well-preserved, discrete chromosomoids the relative size of the chromosomoid and its associated chromosomal elements were correlated, and in several cases more than the diploid number of each was present, suggesting that any part of the chromosome can elaborate chromosomoidal material.

The kinetochore of the hemiptera

Summary(1)Breakage of chromosomes was induced by X-rays in adult and nymphal males of Euschistus servus, E. tristigmus and Solubea pugnax (Pentatomidae; Hemiptera-Heteroptera).(2)The diffuse nature

Chromosome behavior of the cimex pilosellus complex (Cimicidae: Hemiptera)

In the hybrid, clear evidence of meiotic sequence is obtained from observation of the behavior of heteromorphic bivalents and the trivalent, and the autosomes co-orient and are reductional at the first meiosis and auto-orient.

The organization and ultrastructure of male meiotic chromosomes in oncopeltus fasciatus

The structural basis of the heteropycnocity of the sex univalents as determined by the electron microscope supports the concept of heterochromatin as representing tightly coiled chromosome material.

Post-Reductional Meiosis: Its Mechanism and Causes

Proof that the regular mitotic cycle takes place for chromosome fragments induced by the irradiation is obtained and the lack of any heteromorphous bivalent and the uniform tetrapartite structure of all five bivalents preclude certainty regarding the actual occurrence of post-reduction.

Holocentric chromosomes in Oncopeltus: kinetochore plates are present in mitosis but absent in meiosis

Fine structure studies of Oncopeltus fasciatus, an hemipteran with diffuse kinetochores, shows the presence of aKinetochore plate extending for up to 75% of the length of the chromosomes during mitosis, and it is suggested that in organisms with holocentric chromosomes the formation of the meiotic kinetchore apparatus may have to be suppressed to allow terminalization of chiasmata.

Zur Karyologie der Hydrachnellen (Acarina)

BeiEylais setosa zeigen röntgeninduzierte Chromosomenfragmente eine ungestörte Teilungsfähigkeit, was als Beweis f for holokinetische Chromosom zu gelten hat.

Aceto-Iron-Haematoxylin-Chloral Hydrate for Chromosome Staining

This stain gives best results in zoological and botanical material not requiring hydrolysis, e.g., leucocytes, ascites cells, and cells undergoing spermatogenesis and microsporogenesis.