scholarly journals Induction of Metamorphosis Causes Differences in Sex-Specific Allocation Patterns in Axolotls (Ambystoma mexicanum) that Have Different Growth Histories

2015 ◽  
Vol 49 (4) ◽  
pp. 621-626 ◽  
Author(s):  
Pamela M. Clarkson ◽  
Christopher K. Beachy
2009 ◽  
Vol 2009 (8) ◽  
pp. pdb.prot5268-pdb.prot5268 ◽  
Author(s):  
R. B. Page ◽  
S. R. Voss

Author(s):  
Larry F. Lemanski ◽  
Eldridge M. Bertke ◽  
J. T. Justus

A recessive mutation has been recently described in the Mexican Axolotl, Ambystoma mexicanum; in which the heart forms structurally, but does not contract (Humphrey, 1968. Anat. Rec. 160:475). In this study, the fine structure of myocardial cells from normal (+/+; +/c) and cardiac lethal mutant (c/c) embryos at Harrison's stage 40 was compared. The hearts were fixed in a 0.1 M phosphate buffered formaldehyde-glutaraldehyde-picric acid-styphnic acid mixture and were post fixed in 0.1 M s-collidine buffered 1% osmium tetroxide. A detailed study of heart development in normal and mutant embryos from stages 25-46 will be described elsewhere.


Author(s):  
Ezzatollah Keyhani ◽  
Larry F. Lemanski ◽  
Sharon L. Lemanski

Energy for sperm motility is provided by both glycolytic and respiratory pathways. Mitochondria are involved in the latter pathway and conserve energy of substrate oxidation by coupling to phosphorylation. During spermatogenesis, the mitochondria undergo extensive transformation which in many species leads to the formation of a nebemkem. The nebemkem subsequently forms into a helix around the axial filament complex in the middle piece of spermatozoa.Immature spermatozoa of axolotls contain numerous small spherical mitochondria which are randomly distributed throughout the cytoplasm (Fig. 1). As maturation progresses, the mitochondria appear to migrate to the middle piece region where they become tightly packed to form a crystalline-like sheath. The cytoplasm in this region is no longer abundant (Fig. 2) and the plasma membrane is now closely apposed to the outside of the mitochondrial layer.


Author(s):  
Mohinder S. Jarial

The axolotl is a strictly aquatic salamander in which the larval external gills are retained throughout life. The external gills of the adult axolotl have been studied by light and electron microscopy for ultrastructural evidence of ionic transport. The thin epidermis of the gill filaments and gill stems is composed of 3 cell types: granular cells, the basal cells and a sparce population of intervening Leydig cells. The gill epidermis is devoid of muscles, and no mitotic figures were observed in any of its cells.The granular cells cover the gill surface as a continuous layer (Fig. 1, G) and contain secretory granules of different forms, located apically (Figs.1, 2, SG). Some granules are found intimately associated with the apical membrane while others fuse with it and release their contents onto the external surface (Fig. 3). The apical membranes of the granular cells exhibit microvilli which are covered by a PAS+ fuzzy coat, termed “glycocalyx” (Fig. 2, MV).


2019 ◽  
Vol 53 (5) ◽  
pp. 375-384
Author(s):  
M. Drohvalenko ◽  
A. Mykhailenko ◽  
M. Rekrotchuk ◽  
L. Shpak ◽  
V. Shuba ◽  
...  

Abstract A part of the COI mitochondrial barcoding gene was sequenced from seven species of different taxonomical groups: Ambystoma mexicanum (Amphibia, Ambystomatidae), Darevskia lindholmi, Lacerta agilis exigua (Reptilia, Lacertidae), Erinaceus roumanicus (Mammalia, Erinaceidae), Macrobiotus sp. 1 and 2 (Eutardigrada, Macrobiotidae) and Cameraria ohridella (Insecta, Gracillariidae). The sequences were compared with available sequences from databases and positioned on phylogenetic trees when the taxa had not yet been sequenced. The presence of Mexican axolotls in herpetoculture in Ukraine was confirmed. The partial COI genes of the Crimean rock lizard and an eastern sub-species of the sand lizard were sequenced. We demonstrated the presence of two tardigrade mitochondrial lineages of the Macrobiotus hufelandi group in the same sample from the Zeya Natural Reserve in the Far East: one was nearly identical to the Italian M. macrocalix, and the other one is similar to M. persimilis and M. vladimiri. We also confirmed the presence of the invasive haplotype “A” of the horse chestnut leaf miner in Ukraine, in line with the hypothesized route of invasion from Central Europe.


Peptides ◽  
1993 ◽  
Vol 14 (5) ◽  
pp. 1029-1035 ◽  
Author(s):  
Robert M. Dores ◽  
Frances L. Sandoval ◽  
Lorraine K. McDonald

1983 ◽  
Vol 61 (7) ◽  
pp. 1955-1958 ◽  
Author(s):  
Marvin P. Pritts ◽  
James F. Hancock

The population structure and growth patterns of two populations of Solidago pauciflosculosa, a woody goldenrod, were investigated. Populations consisted of even-aged contagious patches of individuals, a dispersion pattern likely caused by the periodic appearance of microsites suitable for seedling establishment. The density of individuals within the even-aged clumps varied considerably and was correlated with total plant biomass and reproductive output. Density was not correlated with either reproductive or nonreproductive allocation patterns.


1991 ◽  
Vol 23 (3) ◽  
pp. 377-384 ◽  
Author(s):  
F. Oehmen ◽  
G. Aumüller ◽  
M. Bergmann ◽  
J. Seitz
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document