Difference in muscle spindle structure between pigeon muscles used in aerial and terrestrial locomotion

1983 ◽  
Vol 168 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Alfred Maier
Keyword(s):  
Muscle Spindle ◽  
Terrestrial Locomotion ◽  
Spindle Structure

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

Spindle scaling mechanisms

2020 ◽  
Vol 64 (2) ◽  
pp. 383-396
Author(s):  
Lara K. Krüger ◽  
Phong T. Tran
Keyword(s):  
Cell Size ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Size Dependent ◽  
A Cell ◽  
Chromosome Separation ◽  
Spindle Elongation ◽  
Protein Gradients ◽  
Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

The hominin lineage

2017 ◽  
Author(s):  
Francisco J. Ayala ◽  
Camilo J. Cela-Conde
Keyword(s):  
Rift Valley ◽  
Climate Changes ◽  
Human Lineage ◽  
Terrestrial Locomotion ◽  
Geological Formations ◽  
Difficult Issue ◽  
Human Fossils

This chapter describes the origin of the human lineage within the evolution of the hominoids, which raises the difficult issue of how to integrate the evolution of dentition and terrestrial locomotion. Next is the investigation of the appearance and initial dispersal of the hominins toward the end of the Miocene, with particular attention to the models of colonization of new territories as a function of climate changes. The hypothesis of the adaptation to the open savanna by bipedalism is explored. Finally, there is a summary description of the different deposits and localities of the main African localities with human fossils, pointing out the different geological formations and exemplars found in each deposit, including two sites north of the Rift Valley of great importance: Toros-Menalla (Tchad) and Dmanisi (Georgia).

Muscle Spindle Composition and Distribution in Human Young Masseter and Biceps Brachii Muscles Reveal Early Growth and Maturation

2011 ◽  
Vol 294 (4) ◽  
pp. 683-693 ◽  
Author(s):  
Catharina Österlund ◽  
Jing-Xia Liu ◽  
Lars-Eric Thornell ◽  
Per-Olof Eriksson
Keyword(s):  
Muscle Spindle ◽  
Biceps Brachii ◽  
Early Growth

Calcium spikes in frog muscle spindle

1979 ◽  
Vol 11 ◽  
pp. 2
Author(s):  
Fumio Ito ◽  
Tadashi Akaike ◽  
Yukio Komatsu
Keyword(s):  
Muscle Spindle ◽  
Frog Muscle ◽  
Calcium Spikes
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