Compliance of the fish outflow tract is altered by thermal acclimation through connective tissue remodelling

To protect the gill capillaries from high systolic pulse pressure, the fish heart contains a compliant non-contractile chamber called the bulbus arteriosus which is part of the outflow tract (OFT) which extends from the ventricle to the ventral aorta. Thermal acclimation alters the form and function of the fish atria and ventricle to ensure appropriate cardiac output at different temperatures, but its impact on the OFT is unknown. Here we used ex vivo pressure–volume curves to demonstrate remodelling of passive stiffness in the rainbow trout ( Oncorhynchus mykiss ) bulbus arteriosus following more than eight weeks of thermal acclimation to 5, 10 and 18°C. We then combined novel, non-biased Fourier transform infrared spectroscopy with classic histological staining to show that changes in compliance were achieved by changes in tissue collagen-to-elastin ratio. In situ gelatin zymography and SDS-PAGE zymography revealed that collagen remodelling was underpinned, at least in part, by changes in activity and abundance of collagen degrading matrix metalloproteinases. Collectively, we provide the first indication of bulbus arteriosus thermal remodelling in a fish and suggest this remodelling ensures optimal blood flow and blood pressure in the OFT during temperature change.

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Form and function of the bulbus arteriosus in yellowfin tuna (Thunnus albacares): dynamic properties

Journal of Experimental Biology ◽

10.1242/jeb.00576 ◽

2003 ◽

Vol 206 (19) ◽

pp. 3327-3335 ◽

Cited By ~ 19

Author(s):

M. H. Braun

Keyword(s):

Dynamic Properties ◽

Yellowfin Tuna ◽

Thunnus Albacares ◽

Form And Function ◽

Bulbus Arteriosus ◽

And Function

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Form and function of the bulbus arteriosus in yellowfin tuna (Thunnus albacares), bigeye tuna (Thunnus obesus) and blue marlin (Makaira nigricans): static properties

Journal of Experimental Biology ◽

10.1242/jeb.00575 ◽

2003 ◽

Vol 206 (19) ◽

pp. 3311-3326 ◽

Cited By ~ 26

Author(s):

M. H. Braun

Keyword(s):

Yellowfin Tuna ◽

Thunnus Albacares ◽

Bigeye Tuna ◽

Static Properties ◽

Form And Function ◽

Blue Marlin ◽

Makaira Nigricans ◽

Thunnus Obesus ◽

Bulbus Arteriosus ◽

And Function

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Geometrical & Interfacial Modulation of a Biomimetic Spinal Implant

Journal of Biomimetics Biomaterials and Tissue Engineering ◽

10.4028/www.scientific.net/jbbte.4.41 ◽

2009 ◽

Vol 4 ◽

pp. 41-58

Author(s):

P. Lok ◽

Philip Boughton ◽

T. Kishen ◽

Ashish D. Diwan

Keyword(s):

Surface Area ◽

Axial Loading ◽

Interfacial Stress ◽

Implant Design ◽

Tissue Remodelling ◽

Design Elements ◽

Spinal Implant ◽

Form And Function ◽

Spinal Disc ◽

And Function

The nucleus of a spinal disc is seamlessly connective and protectively supportive of the joint within which it is enveloped. A range of nucleus prosthesis configurations have been proposed and applied with some success. Those that have demonstrated clinical efficacy have approximated physiological form and function using established biomaterials while preserving key anatomical structures. The minimally invasive biostable, biomimetic Columna Disc Device (CDD) partial spinal disc replacement has been developed to clinical trial stage. It mimics the geometry and response of the nucleus that it replaces. While the implant configuration and materials have been set, the geometry and interfacial properties of this prosthesis may be modulated to account for versatility in surgical deployment, implant stiffness, and subsequent long-term tissue remodelling response. FEA models were developed to study effects of implant jacket geometry and surface properties on implant deployment and biomechanics. Studded and dimpled textures provide a method for increasing surface area to diffuse jacket-filler interfacial stress and similar for the implant-tissue junction. Surface texture design elements observed in nature can protect against delamination and interlayer slippage. This is the case with adherent outer layers of human skin. A textured implant design is also proposed to guard against third body wear by housing debris remote of wear sites and by reducing sliding. The periodically varying strain fields provided by the textured jacket may also help mitigate for tears by diverting and arresting micro-fissures. Increasing friction at the implant-tissue interface to the point of tissue-attachment was shown to increase the stiffness of the implant in axial-loading. In contrast, increasing bulk surface area is expected to contribute to a decrease in implant stiffness. This is, however, dependent on the intimacy and properties of interfacing tissues.

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Scanning tunneling microscopy (STM) of DNA and RNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152148 ◽

1989 ◽

Vol 47 ◽

pp. 34-35

Author(s):

Patricia G. Arscott ◽

Gil Lee ◽

Victor A. Bloomfield ◽

D. Fennell Evans

Keyword(s):

Molecular Structures ◽

Inorganic Materials ◽

Resolving Power ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Form And Function ◽

Dna And Rna ◽

Calf Thymus ◽

And Function ◽

The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

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