scholarly journals Giant Oocytes with Two Meiotic Spindles and Two Polar Bodies: Report of Two Cases

2017 ◽  
Vol 3 (2) ◽  
pp. 1-3
Author(s):  
Baris Baykal
Keyword(s):  
Polar Bodies ◽  
Meiotic Spindles

scholarly journals Kinesin-1 mediates translocation of the meiotic spindle to the oocyte cortex through KCA-1, a novel cargo adapter

2005 ◽  
Vol 169 (3) ◽  
pp. 447-457 ◽  
Author(s):  
Hsin-ya Yang ◽  
Paul E. Mains ◽  
Francis J. McNally
Keyword(s):  
Meiotic Spindle ◽  
Cell Cortex ◽  
Anaphase Promoting Complex ◽  
Wild Type ◽  
Kinesin Light Chain ◽  
Polar Bodies ◽  
Meiotic Spindles ◽  
Redundant Mechanism ◽  
Meiosis I ◽  
Egg Cortex

In animals, female meiotic spindles are attached to the egg cortex in a perpendicular orientation at anaphase to allow the selective disposal of three haploid chromosome sets into polar bodies. We have identified a complex of interacting Caenorhabditis elegans proteins that are involved in the earliest step in asymmetric positioning of anastral meiotic spindles, translocation to the cortex. This complex is composed of the kinesin-1 heavy chain orthologue, UNC-116, the kinesin light chain orthologues, KLC-1 and -2, and a novel cargo adaptor, KCA-1. Depletion of any of these subunits by RNA interference resulted in meiosis I metaphase spindles that remained stationary at a position several micrometers from the cell cortex during the time when wild-type spindles translocated to the cortex. After this prolonged stationary period, unc-116(RNAi) spindles moved to the cortex through a partially redundant mechanism that is dependent on the anaphase-promoting complex. This study thus reveals two sequential mechanisms for translocating anastral spindles to the oocyte cortex.

scholarly journals Dynactin-dependent cortical dynein and spherical spindle shape correlate temporally with meiotic spindle rotation in Caenorhabditis elegans

2015 ◽  
Vol 26 (17) ◽  
pp. 3030-3046 ◽  
Author(s):  
Marina E. Crowder ◽  
Jonathan R. Flynn ◽  
Karen P. McNally ◽  
Daniel B. Cortes ◽  
Kari L. Price ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Spherical Shape ◽  
Nematode Species ◽  
Meiotic Spindle ◽  
Present Evidence ◽  
Basic Domain ◽  
C Elegans ◽  
Polar Bodies ◽  
Spindle Rotation ◽  
Meiotic Spindles

Oocyte meiotic spindles orient with one pole juxtaposed to the cortex to facilitate extrusion of chromosomes into polar bodies. In Caenorhabditis elegans, these acentriolar spindles initially orient parallel to the cortex and then rotate to the perpendicular orientation. To understand the mechanism of spindle rotation, we characterized events that correlated temporally with rotation, including shortening of the spindle in the pole-to pole axis, which resulted in a nearly spherical spindle at rotation. By analyzing large spindles of polyploid C. elegans and a related nematode species, we found that spindle rotation initiated at a defined spherical shape rather than at a defined spindle length. In addition, dynein accumulated on the cortex just before rotation, and microtubules grew from the spindle with plus ends outward during rotation. Dynactin depletion prevented accumulation of dynein on the cortex and prevented spindle rotation independently of effects on spindle shape. These results support a cortical pulling model in which spindle shape might facilitate rotation because a sphere can rotate without deforming the adjacent elastic cytoplasm. We also present evidence that activation of spindle rotation is promoted by dephosphorylation of the basic domain of p150 dynactin.

scholarly journals General (p,q)-mixed projection bodies

2020 ◽  
Vol 18 (1) ◽  
pp. 970-982
Author(s):  
Yibin Feng ◽  
Yanping Zhou
Keyword(s):  
Extreme Values ◽  
Basic Properties ◽  
Polar Bodies ◽  
Mixed Projection Bodies ◽  
Projection Bodies

Abstract In this article, the general (p,q)-mixed projection bodies are introduced. Then, some basic properties of the general (p,q)-mixed projection bodies are discussed, and the extreme values of volumes of the general (p,q)-mixed projection bodies and their polar bodies are established.

scholarly journals Preimplantation Genetic Diagnosis—An Overview

2005 ◽  
Vol 53 (3) ◽  
pp. 255-260 ◽  
Author(s):  
Caroline Mackie Ogilvie ◽  
Peter R. Braude ◽  
Paul N. Scriven
Keyword(s):  
Preimplantation Genetic Diagnosis ◽  
Genetic Diagnosis ◽  
Sex Selection ◽  
Hla Typing ◽  
Success Rates ◽  
Aneuploidy Screening ◽  
Reciprocal Translocations ◽  
Public Controversy ◽  
Polar Bodies ◽  
Monogenic Diseases

Since the early 1990s, preimplantation genetic diagnosis (PGD) has been expanding in scope and applications. Selection of female embryos to avoid X-linked disease was carried out first by polymerase chain reaction, then by fluorescence in situ hybridization (FISH), and an ever-increasing number of tests for monogenic diseases have been developed. Couples with chromosome rearrangements such as Robertsonian and reciprocal translocations form a large referral group for most PGD centers and present a special challenge, due to the large number of genetically unbalanced embryos generated by meiotic segregation. Early protocols used blastomeres biopsied from cleavage-stage embryos; testing of first and second polar bodies is now a routine alternative, and blastocyst biopsy can also be used. More recently, the technology has been harnessed to provide PGD-AS, or aneuploidy screening. FISH probes specific for chromosomes commonly found to be aneuploid in early pregnancy loss are used to test blastomeres for aneuploidy, with the aim of replacing euploid embryos and increasing pregnancy rates in groups of women who have poor IVF success rates. More recent application of PGD to areas such as HLA typing and social sex selection have stoked public controversy and concern, while provoking interesting ethical debates and keeping PGD firmly in the public eye.

Msps protein is localized to acentrosomal poles to ensure bipolarity of Drosophila meiotic spindles

2001 ◽  
Vol 3 (7) ◽  
pp. 637-642 ◽  
Author(s):  
C. Fiona Cullen ◽  
Hiroyuki Ohkura
Keyword(s):  
Meiotic Spindles

scholarly journals Apomictic parthenogenesis in a parasitoid waspMeteorus pulchricornis, uncommon in the haplodiploid order Hymenoptera

2014 ◽  
Vol 104 (3) ◽  
pp. 307-313 ◽  
Author(s):  
Y. Tsutsui ◽  
K. Maeto ◽  
K. Hamaguchi ◽  
Y. Isaki ◽  
Y. Takami ◽  
...  
Keyword(s):  
Parasitoid Wasp ◽  
Parasitoid Wasps ◽  
Genetic Studies ◽  
Insect Order ◽  
Egg Maturation ◽  
Polar Bodies ◽  
Lepidopteran Larvae ◽  
Apomictic Parthenogenesis ◽  
Meteorus Pulchricornis ◽  
New Type

AbstractAlthough apomixis is the most common form of parthenogenesis in diplodiploid arthropods, it is uncommon in the haplodiploid insect order Hymenoptera. We found a new type of spontaneous apomixis in the Hymenoptera, completely lacking meiosis and the expulsion of polar bodies in egg maturation division, on the thelytokous strain of a parasitoid waspMeteorus pulchricornis(Wesmael) (Braconidae, Euphorinae) on pest lepidopteran larvaeSpodoptera litura(Fabricius) (Noctuidae). The absence of the meiotic process was consistent with a non-segregation pattern in the offspring of heterozygous females, and no positive evidence was obtained for the induction of thelytoky by any bacterial symbionts. We discuss the conditions that enable the occurrence of such rare cases of apomictic thelytoky in the Hymenoptera, suggesting the significance of fixed heterosis caused by hybridization or polyploidization, symbiosis with bacterial agents, and occasional sex. Our finding will encourage further genetic studies on parasitoid wasps to use asexual lines more wisely for biological control.

Fate of Polar Bodies in Insects

1973 ◽  
Vol 18 (1) ◽  
pp. 421-444 ◽  
Author(s):  
E. Tremblay ◽  
L. E. Caltagirone
Keyword(s):  
Polar Bodies

The Chromosome Numbers of certain Barnacles in British Waters

1958 ◽  
Vol s3-99 (48) ◽  
pp. 497-504
Author(s):  
A. P. AUSTIN ◽  
D. J. CRISP ◽  
A. M. PATIL
Keyword(s):  
Chromosome Numbers ◽  
Mantle Cavity ◽  
Polar Bodies ◽  
Iron Alum ◽  
Cytological Changes

The chromosome numbers of nine species of sessile barnacles have been determined from squashes of young embryos stained by an iron alum aceto-carmine method. All the species of Balanus examined, and Elminius modestus had a diploid count of 32 chromosomes. Chthamalus stellatus and Verruca stroemia had each 30 chromosomes. Meiosis occurs after the egg passes into the mantle cavity, and the cytological changes accompanying the extrusion of the two polar bodies are figured.

Sign in / Sign up

Export Citation Format

Share Document