scholarly journals The relationship between head shape, head musculature and bite force in caecilians (Amphibia: Gymnophiona)

2021 ◽  
Author(s):  
Aurélien Lowie ◽  
Barbara De Kegel ◽  
Mark Wilkinson ◽  
John Measey ◽  
James C. O'Reilly ◽  
...  
Keyword(s):  
Bite Force ◽  
Temporal Region ◽  
Head Shape ◽  
Skull Shape ◽  
Form And Function ◽  
Feeding Mechanics ◽  
Mandible Shape ◽  
And Function ◽  
The Relationship

Caecilians are enigmatic limbless amphibians that, with a few exceptions all have an at least partly burrowing lifestyle. Although it has been suggested that caecilian evolution resulted in sturdy and compact skulls as an adaptation to their head-first burrowing habits, no relationship between skull shape and burrowing performance has been demonstrated to date. However, the unique dual jaw-closing mechanism and the osteological variability of their temporal region suggest a potential relationship between skull shape and feeding mechanics. Here, we explored the relationships between skull shape, head musculature, and in vivo bite forces. Although there is a correlation between bite force and external head shape, no relationship between bite force and skull shape could be detected. Whereas our data suggest that muscles are the principal drivers of variation in bite force, the shape of the skull is constrained by factors other than demands for bite force generation. However, a strong covariation between the cranium and mandible exists. Moreover, both cranium and mandible shape covary with jaw muscle architecture. Caecilians show a gradient between species with a long retroarticular process associated with a large and pennate-fibered m. interhyoideus posterior and species with a short process but long and parallel-fibered jaw adductors. Our results demonstrate the complexity of the relationship between form and function of this jaw system. Further studies that focus on factors such as gape distance or jaw velocity will be needed in order to fully understand the evolution of feeding mechanics in caecilians.

scholarly journals Under pressure: the relationship between cranial shape and burrowing force in caecilians (Gymnophiona)

2021 ◽  
Author(s):  
Aurélien Lowie ◽  
Barbara De Kegel ◽  
Mark Wilkinson ◽  
John Measey ◽  
James C. O'Reilly ◽  
...  
Keyword(s):  
Phylogenetic Signal ◽  
Three Dimensional ◽  
Form And Function ◽  
Biomechanical Models ◽  
Cranial Osteology ◽  
Head Morphology ◽  
And Function ◽  
The Relationship ◽  
Cranial Shape

Caecilians are elongate, limbless, and annulated amphibians that, with the exception of one aquatic family, all have an at least partly fossorial lifestyle. It has been suggested that caecilian evolution resulted in sturdy and compact skulls with fused bones and tight sutures, as an adaptation to their head-first burrowing habits. However, although their cranial osteology is well described, relationships between form and function remain poorly understood. In the present study, we explored the relationship between cranial shape and in vivo burrowing forces. Using µCT-data, we performed three-dimensional geometric morphometrics to explore whether cranial and mandibular shapes reflected patterns that might be associated with maximal push forces. The results highlight important differences in maximal push forces, with the aquatic Typhlonectes producing a lower force for a given size compared to other species. Despite substantial differences in head morphology across species, no relation between overall skull shape and push force could be detected. Although a strong phylogenetic signal may partly obscure the results, our conclusions confirm previous studies using biomechanical models and suggest that differences in the degree of fossoriality do not appear to be driving the evolution of head shape.

Decoupled ontogeny of in vivo bite force and mandible morphology reveals effects of weaning and sexual maturation in mice

2020 ◽  
Vol 129 (3) ◽  
pp. 558-569
Author(s):  
Samuel Ginot ◽  
Lionel Hautier ◽  
Sylvie Agret ◽  
Julien Claude
Keyword(s):  
Sexual Maturation ◽  
Bite Force ◽  
Second Phase ◽  
Hormonal Changes ◽  
Skull Morphology ◽  
Form And Function ◽  
Weaning Stress ◽  
And Function ◽  
Mandible Size

Abstract The link between performance, morphology and their sources of variation is a major target of evolutionary functional biology. In vertebrates, many studies have linked in vivo bite force to skull morphology, mostly at the interspecific level. Within species, however, the ontogeny of bite force, in relation to the development of the mandible, remains poorly known, despite its relevance for life history and for the co-evolution of form and function. Here, ontogenetic trajectories of bite force, correlated with mandible size and shape, are reported for the first time in a wild-derived colony of laboratory mice. Bite forces were measured in vivo and mandible morphology was assessed using geometric morphometrics. Most coordinated changes in morphology and in vivo bite force occur during the first stages of growth, prior to weaning. Mandible shape stabilizes after day 23. The increases in mandible size and body mass slow down around day 40, but still increase during adulthood. Despite slowing down after weaning, bite force increases through a second phase during sexual maturation (days 30–40). This may be linked to the progressive tempering of weaning stress, continued growth and synchronization of the muscular and osteological systems, together with hormonal changes, as we observed a concomitant appearance of sexual dimorphism.

Scanning tunneling microscopy (STM) of DNA and RNA

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).

scholarly journals Enhancing ultrasound texture differences for developing an in vivo 'virtual histology' approach to bovine ovarian imaging

2007 ◽  
Vol 19 (8) ◽  
pp. 910 ◽  
Author(s):  
Mark G. Eramian ◽  
Gregg P. Adams ◽  
Roger A. Pierson
Keyword(s):  
Image Processing ◽  
Ultrasound Image ◽  
Ultrasound Images ◽  
Virtual Histology ◽  
Form And Function ◽  
Non Invasive ◽  
Candidate Image ◽  
And Function ◽  
Processing Techniques

A ‘virtual histology’ can be thought of as the ‘staining’ of a digital ultrasound image via image processing techniques in order to enhance the visualisation of differences in the echotexture of different types of tissues. Several candidate image-processing algorithms for virtual histology using ultrasound images of the bovine ovary were studied. The candidate algorithms were evaluated qualitatively for the ability to enhance the visual differences in intra-ovarian structures and quantitatively, using standard texture description features, for the ability to increase statistical differences in the echotexture of different ovarian tissues. Certain algorithms were found to create textures that were representative of ovarian micro-anatomical structures that one would observe in actual histology. Quantitative analysis using standard texture description features showed that our algorithms increased the statistical differences in the echotexture of stroma regions and corpus luteum regions. This work represents a first step toward both a general algorithm for the virtual histology of ultrasound images and understanding dynamic changes in form and function of the ovary at the microscopic level in a safe, repeatable and non-invasive way.

Relationship of Skeletal Muscle Atrophy to Functional Status: A Systematic Research Review

2000 ◽  
Vol 2 (2) ◽  
pp. 117-131 ◽  
Author(s):  
Kathleen Michael
Keyword(s):  
Muscle Atrophy ◽  
Elderly Women ◽  
Functional Limitation ◽  
Skeletal Muscle Atrophy ◽  
Research Review ◽  
Systematic Research ◽  
Form And Function ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

In the realm of muscle atrophy research, many studies address minute details of molecular function but few examine the effects of atrophy in terms of mobility, strength, endurance, and performance of activities of daily living. The relationship between impairment and functional limitation is the focus of this research review. A wide array of studies constitute this area of inquiry, including investigations as diverse and widely disparate as molecular chemistry and space travel and populations as different as rats, healthy young men, and elderly women. Thirty-four studies were selected based on their fit with the Enabling-Disabling Model. Three paradigms of atrophy and function emerged. Adaptation reflects the plastic nature of muscle when placed under certain conditions, ranging from disuse to high-resistance exercise. Injury/loss describes damage to muscle tissue from ischemia, medications, or reloading or reperfusion trauma. Also in this category is the loss of muscle that is seen with aging. Integrity relates to the muscle’s tendency to protect itself and maintain structural adjacencies and cellular proportions. Based on the 3 muscle research paradigms, the relationship of muscle atrophy to function is portrayed as a bidirectional interaction wherein form and function have an influence on each other by way of physical changes, including those of adaptation, injury/loss, or integrity. A conceptual model is constructed to reflect this relationship.

scholarly journals A-Kinase Anchoring Protein 1: Emerging Roles in Regulating Mitochondrial Form and Function in Health and Disease

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 298 ◽  
Author(s):  
Yujia Liu ◽  
Ronald A. Merrill ◽  
Stefan Strack
Keyword(s):  
Cell Survival ◽  
Intracellular Signaling ◽  
Neuronal Cell ◽  
Supporting Cell ◽  
In Vivo Studies ◽  
Form And Function ◽  
Anchoring Protein ◽  
Cancer Tumor ◽  
And Function

Best known as the powerhouse of the cell, mitochondria have many other important functions such as buffering intracellular calcium and reactive oxygen species levels, initiating apoptosis and supporting cell proliferation and survival. Mitochondria are also dynamic organelles that are constantly undergoing fission and fusion to meet specific functional needs. These processes and functions are regulated by intracellular signaling at the mitochondria. A-kinase anchoring protein 1 (AKAP1) is a scaffold protein that recruits protein kinase A (PKA), other signaling proteins, as well as RNA to the outer mitochondrial membrane. Hence, AKAP1 can be considered a mitochondrial signaling hub. In this review, we discuss what is currently known about AKAP1′s function in health and diseases. We focus on the recent literature on AKAP1′s roles in metabolic homeostasis, cancer and cardiovascular and neurodegenerative diseases. In healthy tissues, AKAP1 has been shown to be important for driving mitochondrial respiration during exercise and for mitochondrial DNA replication and quality control. Several recent in vivo studies using AKAP1 knockout mice have elucidated the role of AKAP1 in supporting cardiovascular, lung and neuronal cell survival in the stressful post-ischemic environment. In addition, we discuss the unique involvement of AKAP1 in cancer tumor growth, metastasis and resistance to chemotherapy. Collectively, the data indicate that AKAP1 promotes cell survival throug regulating mitochondrial form and function. Lastly, we discuss the potential of targeting of AKAP1 for therapy of various disorders.

scholarly journals Sophistication of foldamer form and function in vitro and in vivo

2007 ◽  
Vol 11 (6) ◽  
pp. 685-692 ◽  
Author(s):  
Arjel D Bautista ◽  
Cody J Craig ◽  
Elizabeth A Harker ◽  
Alanna Schepartz
Keyword(s):  
Form And Function ◽  
And Function

Verb inflection in Ancient Greek and Sanskrit and auxiliation patterns in French and Italian

2009 ◽  
Vol 32 (1) ◽  
pp. 55-76 ◽  
Author(s):  
Nunzio La Fauci ◽  
Liana Tronci
Keyword(s):  
Complex Interaction ◽  
Ancient Greek ◽  
Form And Function ◽  
European Languages ◽  
Verb Inflection ◽  
The Subject ◽  
The Difference ◽  
Verb Inflections ◽  
And Function ◽  
The Relationship

This paper deals with the complex interaction between form and function in the verb morphosyntax of four Indo-European languages (French, Italian, Ancient Greek and Sanskrit). Beyond the difference in form, auxiliation patterns in French and Italian, and verb inflections in Ancient Greek and Sanskrit correlate, thanks to the agreement for number and person, to the expression of the relationship with the Subject. The different auxiliation patterns (sum and habeo) and the different inflections (middle and active) correlate to different properties of the Subject. In particular, these forms depend on the syntactic opposition between middle and non-middle. The ways of this dependency are regulated and systematic, although they appear fuzzy and chaotic, not only if the four languages are compared to each other, but also if different morphosyntactic combinations, inside the same language, are concerned.

Towards a pragmatic approach to the study of languages in contact

Pragmatics ◽  
1991 ◽  
Vol 1 (4) ◽  
pp. 465-480 ◽  
Author(s):  
Joan A. Argente ◽  
Lluís Payrató
Keyword(s):  
Language Contact ◽  
Communicative Competence ◽  
Form And Function ◽  
Languages In Contact ◽  
The Social ◽  
Interactive Strategies ◽  
And Function ◽  
Adaptation Processes ◽  
The Relationship ◽  
New Distribution

The study of language contact has been traditionally carried out from a structural perspective (synchronic or diachronic), from a sociolinguistic perspective and/or from a rather psychological perspective, centered on the linguistic and communicative competence of the multilingual individual. However, a great number of linguistic and sociolinguistic topics that appear in language contact situations may be productively tackled from a pragmatic viewpoint. This pragmatic perspective takes into account linguistic use in communication contexts and raises, at a different level, questions that deal with the structures and the evolution of the codes in contact. The main aim of this presentation is the analysis of some of the specific problems that arise in given language contact situations from a pragmatic perspective, considering the adaptation processes of the speakers, their particular interactive strategies and the social meaning generated. Understanding pragmatics in its original sense, i.e. as the study of the relationship between linguistic signs and speakers (users of certain resources), these phenomena should be understood as the result of speakers’ adaptation to changing sociocultural circumstances. This adaptation creates a new distribution of the verbal resources (or linguistic economy) of the community and, consequently, modifies its varieties as far as form and function are concerned.

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