scholarly journals Magnetically induced behaviour of ferritin corpuscles in avian ears: can cuticulosomes function as magnetosomes?

2015 ◽  
Vol 12 (102) ◽  
pp. 20141087 ◽  
Author(s):  
Petr Jandacka ◽  
Hynek Burda ◽  
Jaromir Pistora
Keyword(s):  
Hair Cells ◽  
Alternative Hypothesis ◽  
Iron Storage ◽  
Low Field ◽  
Physical Simulations ◽  
Geomagnetic Fields ◽  
And Function ◽  
Sensory Ability ◽  
Iron Storage Protein ◽  
Electromagnetic Oscillator

Magnetoreception is an enigmatic, poorly understood sensory ability, described mainly on the basis of behavioural studies in animals of diverse taxa. Recently, corpuscles containing superparamagnetic iron-storage protein ferritin were found in the inner ear hair cells of birds, a predominantly single ferritin corpuscle per cell. It was suggested that these corpuscles might represent magnetosomes and function as magnetosensors. Here we determine ferritin low-field paramagnetic susceptibility to estimate its magnetically induced intracellular behaviour. Physical simulations show that ferritin corpuscles cannot be deformed or rotate in weak geomagnetic fields, and thus cannot provide magnetoreception via deformation of the cuticular plate. Furthermore, we reached an alternative hypothesis that ferritin corpuscle in avian ears may function as an intracellular electromagnetic oscillator. Such an oscillator would generate additional cellular electric potential related to normal cell conditions. Though the phenomenon seems to be weak, this effect deserves further analyses.

Polygonal profiles of ferritin molecules

1983 ◽  
Vol 41 ◽  
pp. 600-601
Author(s):  
William H. Massover
Keyword(s):  
Axial Ratio ◽  
X Ray Diffraction ◽  
Rhombic Dodecahedron ◽  
Apparent Contradiction ◽  
Iron Storage ◽  
X Ray ◽  
Hexagonal Shape ◽  
Axes Of Symmetry ◽  
Apparent Conflict ◽  
Iron Storage Protein

The molecular structure of the iron-storage protein, ferritin, is becoming known in ever finer detail. The 24 apoferritin subunits (MW ca. 20,000) have a 2:1 axial ratio and are polymerized with 4:3:2 symmetry to form an outer shell surrounding a variable amount of microcrystalline iron, Recent x-ray diffraction results indicate that the projected outline of the native molecule has a quasi-hexagonal shape when viewed down the 3-fold axes of symmetry, and a quasi-square shape when looking down the 4-fold axes. To date, no electron microscope study has reported observing anything other than circular profiles, which would indicate that ferritin is strictly spherical. The apparent conflict between the "hollow sphere" of electron microscopy (E.M.) and the "truncated rhombic dodecahedron" of x-ray diffraction could reflect the poorer effective resolution of E.M. coming from radiation damage, staining, drying, etc. The present study investigates the detailed shape of individual ferritin molecules in order to search for the predicted aspherical profiles and to interpret the nature of this apparent contradiction.

scholarly journals The microRNA-183/96/182 Cluster is Essential for Stereociliary Bundle Formation and Function of Cochlear Sensory Hair Cells

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ruishuang Geng ◽  
David N Furness ◽  
Chithra K Muraleedharan ◽  
Jinsheng Zhang ◽  
Alain Dabdoub ◽  
...  
Keyword(s):  
Hair Cells ◽  
Sensory Hair ◽  
Sensory Hair Cells ◽  
And Function

Shaker-1 mutations reveal roles for myosin VIIA in both development and function of cochlear hair cells

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 557-566 ◽  
Author(s):  
T. Self ◽  
M. Mahony ◽  
J. Fleming ◽  
J. Walsh ◽  
S.D. Brown ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Usher Syndrome ◽  
Orthologous Gene ◽  
Cell Development ◽  
Cochlear Hair Cells ◽  
Cochlear Hair Cell ◽  
Show Evidence ◽  
Myosin Viia ◽  
And Function

The mouse shaker-1 locus, Myo7a, encodes myosin VIIA and mutations in the orthologous gene in humans cause Usher syndrome type 1B or non-syndromic deafness. Myo7a is expressed very early in sensory hair cell development in the inner ear. We describe the effects of three mutations on cochlear hair cell development and function. In the Myo7a816SB and Myo7a6J mutants, stereocilia grow and form rows of graded heights as normal, but the bundles become progressively more disorganised. Most of these mutants show no gross electrophysiological responses, but some did show evidence of hair cell depolarisation despite the disorganisation of their bundles. In contrast, the original shaker-1 mutants, Myo7ash1, had normal early development of stereocilia bundles, but still showed abnormal cochlear responses. These findings suggest that myosin VIIA is required for normal stereocilia bundle organisation and has a role in the function of cochlear hair cells.

scholarly journals Capuchin monkey rituals: an interdisciplinary study of form and function

2020 ◽  
Vol 375 (1805) ◽  
pp. 20190422 ◽  
Author(s):  
Susan Perry ◽  
Marco Smolla
Keyword(s):  
Alternative Hypothesis ◽  
Capuchin Monkey ◽  
Ritual Performance ◽  
Form And Function ◽  
Sacred Objects ◽  
And Function ◽  
Opening And Closing ◽  
Performance Rate ◽  
Interdisciplinary Study ◽  
Behavioural Repertoire

Many white-faced capuchin monkey dyads in Lomas Barbudal, Costa Rica, practise idiosyncratic interaction sequences that are not part of the species-typical behavioural repertoire. These interactions often include uncomfortable or risky elements. These interactions exhibit the following characteristics commonly featured in definitions of rituals in humans: (i) they involve an unusual intensity of focus on the partner, (ii) the behaviours have no immediate utilitarian purpose, (iii) they sometimes involve ‘sacred objects’, (iv) the distribution of these behaviours suggests that they are invented and spread via social learning, and (v) many behaviours in these rituals are repurposed from other behavioural domains (e.g. extractive foraging). However, in contrast with some definitions of ritual, capuchin rituals are not overly rigid in their form, nor do the sequences have specific opening and closing actions. In our 9260 h of observation, ritual performance rate was uncorrelated with amount of time dyads spent in proximity but (modestly) associated with higher relationship quality and rate of coalition formation across dyads. Our results suggest that capuchin rituals serve a bond-testing rather than a bond-strengthening function. Ritual interactions are exclusively dyadic, and between-dyad consistency in form is low, casting doubt on the alternative hypothesis that they enhance group-wide solidarity. This article is part of the theme issue ‘Ritual renaissance: new insights into the most human of behaviours’.

Analysis of Iron in Ferritin, the Iron-Storage Protein: A General Chemistry Experiment

1998 ◽  
Vol 75 (4) ◽  
pp. 437 ◽  
Author(s):  
Maureen J. Donlin ◽  
Regina F. Frey ◽  
Christopher Putnam ◽  
Jody Proctor ◽  
James K. Bashkin
Keyword(s):  
General Chemistry ◽  
Storage Protein ◽  
Protein A ◽  
Iron Storage ◽  
Chemistry Experiment ◽  
Iron Storage Protein

scholarly journals Preparation of platinum nanoparticles using iron(ii) as reductant and photosensitized H2 generation on an iron storage protein scaffold

RSC Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 5551-5559
Author(s):  
Brenda S. Benavides ◽  
Silvano Valandro ◽  
Donald M. Kurtz
Keyword(s):  
Heavy Chain ◽  
Platinum Nanoparticles ◽  
Storage Protein ◽  
Iron Storage ◽  
Protein Scaffold ◽  
H2 Generation ◽  
Iron Storage Protein

An assembly of platinum nanoparticles produced by Fe(ii) reduction of Pt(ii) and stabilized by human heavy chain ferritin's native catalysis of Fe(ii)(aq) autoxidation functions as an efficient photosensitized H2 evolution catalyst.

scholarly journals MicroRNAs are essential for development and function of inner ear hair cells in vertebrates

2009 ◽  
Vol 106 (19) ◽  
pp. 7915-7920 ◽  
Author(s):  
L. M. Friedman ◽  
A. A. Dror ◽  
E. Mor ◽  
T. Tenne ◽  
G. Toren ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
And Function

scholarly journals Ferritin does not accumulate iron oxidized by caeruloplasmin

1995 ◽  
Vol 305 (1) ◽  
pp. 21-23 ◽  
Author(s):  
A Treffry ◽  
D Gelvan ◽  
A M Konijn ◽  
P M Harrison
Keyword(s):  
Dissolved Oxygen ◽  
Storage Protein ◽  
Iron Oxidation ◽  
Primary Effect ◽  
Significant Extent ◽  
Iron Storage ◽  
Horse Spleen Ferritin ◽  
Iron Storage Protein

Ferritin is an iron-storage protein ubiquitous in mammals, plants and bacteria. It can be reconstituted, in vitro, from the apoprotein and Fe(II) salts in the presence of dissolved oxygen. Recently it has been reported that caeruloplasmin can facilitate apoferritin reconstitution and that iron oxidized by caeruloplasmin is sequestered within the ferritin shell. Here we show that the primary effect of adding caeruloplasmin to horse spleen ferritin during reconstitution is the competition between the two molecules for the iron. This competition results in overall increased rates of iron oxidation and a mixture of products, namely iron-containing ferritin and iron hydroxy polymers attached to caeruloplasmin. Iron oxidized by caeruloplasmin is not incorporated, to any significant extent, into horse spleen ferritin.

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