scholarly journals Progesterone metabolism by the echinoderms Asterias rubens and Marthasterias glacialis (Short Communication)

1974 ◽  
Vol 138 (2) ◽  
pp. 309-311 ◽  
Author(s):  
John Gaffney ◽  
L. John Goad
Keyword(s):  
Short Communication ◽  
Asterias Rubens ◽  
Aqueous Methanol ◽  
Progesterone Metabolism ◽  
Marthasterias Glacialis

The echinoderms Asterias rubens and Marthasterias glacialis metabolize injected [4-14C]progesterone to give labelled 3β-hydroxy-5α-pregnan-20-one and 3β,6α-dihydroxy-5α-pregnan-20-one. These radioactive products are converted by the animals into conjugated forms that are soluble in aqueous methanol, and which have mobilities on t.l.c. similar to the asterosaponins.

A link between predator density and arm loss in the starfish Marthasterias glacialis and Asterias rubens

2000 ◽  
Vol 80 (3) ◽  
pp. 565-566 ◽  
Author(s):  
Kirsten Ramsay ◽  
John R. Turner ◽  
Samantha J. Vize ◽  
Christopher A. Richardson
Keyword(s):  
Significant Positive Correlation ◽  
Significant Proportion ◽  
Asterias Rubens ◽  
Predator Density ◽  
Positive Correlation ◽  
South West ◽  
Cancer Pagurus ◽  
Marthasterias Glacialis ◽  
Lough Hyne

Arm loss in two species of starfish Marthasterias glacialis and Asterias rubens (Echinodermata: Asteroidea) was recorded at eight sites in Lough Hyne, south-west Ireland. There was a significant positive correlation between the density of predators (Luidia ciliaris (Echinodermata: Asteroidea) and Cancer pagurus (Crustacea: Brachyura)) and arm loss in both species of starfish. The results suggest that predators may be responsible for a significant proportion of observed arm loss in these two species of starfish in Lough Hyne.

scholarly journals The Asterias Rubens Sea Star Igkappa Gene when Compared to Marthasterias Glacialis Sea Star Genome (Echinodermata)

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Michel Leclerc
Keyword(s):  
Sea Star ◽  
Asterias Rubens ◽  
High Identity ◽  
Marthasterias Glacialis

The sea star IGKappa gene was cloned in 2014 by the use of primers. It was compared in the present work to Marthasterias glacialis sea star genome. A high identity was found with this last one.

Ultrastructure of primary spermatocyte in fish (Tilapia: Oreochromis niloticus): The synaptonemal complex

1986 ◽  
Vol 44 ◽  
pp. 288-289
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Synaptonemal Complex ◽  
Oreochromis Niloticus ◽  
Short Communication ◽  
Primary Spermatocyte ◽  
Mitotic Division ◽  
Meiotic Cell ◽  
Electron Microscope Level ◽  
Homologous Chromosomes

The Primary Spermatocytes represent a stage in spermatogenesis when the first meiotic cell division occurs. They are derived from Spermatogonium or Stem cell through mitotic division. At the zygotene phase of meiotic prophase the Synaptonemal complex appears in these cells in the space between the paired homologous chromosomes. Spermatogenesis and sperm structure in fish have been studied at the electron microscope level in a few species? However, no work has yet been reported on ultrastructure of tilapia, O. niloticus, spermatozoa and spermatogenetic process. In this short communication we are reporting the Ultrastructure of Primary Spermatocytes in tilapia, O. niloticus, and the fine structure of synaptonemal complexes seen in the spermatocyte nuclei.

SHORT COMMUNICATION

1997 ◽  
Vol 61 (3) ◽  
pp. 275-279 ◽  
Author(s):  
S. MONNO ◽  
Y. MIZUSHIMA ◽  
N. TOYODA ◽  
T. KASHII ◽  
M. KOBAYASHI
Keyword(s):  
Short Communication
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