Oocyte differentiation in Urechis caupo (Echiura): a fine structural study

Journal of Morphology
M Gould-Somero, L Holland

Abstract

The fine structure of oocytes of Urechis caupo is described for seven arbitrary stages ranging from the smallest oocytes (7 mum in diameter) in the coelom to the mature oocytes (115 mum in diameter) in the storage organs. Although most types of cytoplasmic organelles accumulate more or less continuously, yolk granules do not appear until oocytes reach a diameter of 35 mum, and there is stage-specific synthesis of cortical granules in 60-80 mum oocytes. In the nucleus a single nucleolus first appears when an oocyte is 15 mum in diameter. Then a nucleolus satellite, which is about 3 mum in diameter, forms in 30 mum oocytes; this nucleolus satellite later (60-70 mum oocytes) becomes surrounded by 750 nm dense spherical bodies. Large (2-4 mum in diameter) juxtachromosomal spherules occur only in the nuclei of mature oocytes. Microvilli become progressively more numerous and longer until the oocyte reaches a diameter of 90 mum; their tips project 1 mum beyond the fibrous surface coat, which is 2 mum thick when well developed. Near the end of oocyte growth, the microvilli retract into the surface coat leaving their pinched-off tips adhering to the outside of the coat.

References

Sep 1, 1971·Journal of Ultrastructure Research·G Vazquez-Nin, W Bernhard
Mar 21, 1973·Zeitschrift für Zellforschung und mikroskopische Anatomie·M R Kalt
Mar 29, 1973·Zeitschrift für Zellforschung und mikroskopische Anatomie·W Bottke
Sep 1, 1971·Journal of Ultrastructure Research·M R Kalt, B Tandler
Jan 1, 1972·Developmental Biology·F C Davis, F H Wilt
Oct 1, 1970·Proceedings of the National Academy of Sciences of the United States of America·N K DasM Alfert
May 1, 1970·Developmental Biology·I B Dawid, D D Brown
Oct 1, 1970·Developmental Biology·M C Schwartz
Jan 1, 1971·Zeitschrift für Zellforschung und mikroskopische Anatomie·B S Weakley
Jan 1, 1971·Zeitschrift für Zellforschung und mikroskopische Anatomie·I A Gwynn, P C Jones
Nov 15, 1968·Science·L Halkka, O Halkka
Oct 1, 1968·Journal of Ultrastructure Research·A K BalS Inoué
Nov 1, 1968·The Journal of Experimental Zoology·G MillonigL Giambertone
May 1, 1969·Developmental Biology·M C Gould
May 1, 1969·Journal of Ultrastructure Research·A Monneron, W Bernhard
Aug 1, 1965·Developmental Biology·N K DasM Alfert
Oct 1, 1966·The Journal of Cell Biology·B J Stevens, H Swift
Oct 1, 1966·Experimental Cell Research·L E Franklin
Feb 1, 1961·The Journal of Biophysical and Biochemical Cytology·J H LUFT
Dec 1, 1962·Journal of Ultrastructure Research·W J HUMPHREYS

❮ Previous
Next ❯

Citations

Jul 1, 1976·The Journal of Experimental Zoology·M PaulD Epel
Oct 1, 1975·Developmental Biology·M Gould-Somero, L Holland
Jul 1, 1977·Developmental Biology·M Gould-SomeroM Paul
Oct 1, 1983·Developmental Biology·L F Jaffe
Jul 1, 1983·Developmental Biology·R R Franks, F C Davis
Jan 1, 1989·Electron Microscopy Reviews·R G Kessel
Apr 15, 1981·Developmental Biology·L Holland, M Gould-Somero
Jan 7, 1998·Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology·Y OzekiT Matsui
Apr 1, 1976·The Journal of Experimental Zoology·M Paul, M Gould-Somero

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.