scholarly journals Adult Drosophila muscle morphometry through microCT reveals dynamics during ageing

Open Biology ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 190087 ◽  
Author(s):  
Dhananjay Chaturvedi ◽  
Sunil Prabhakar ◽  
Aman Aggarwal ◽  
Krishan B. Atreya ◽  
K. VijayRaghavan

Indirect flight muscles (IFMs) in adult Drosophila provide the key power stroke for wing beating. They also serve as a valuable model for studying muscle development. An age-dependent decline in Drosophila free flight has been documented, but its relation to gross muscle structure has not yet been explored satisfactorily. Such analyses are impeded by conventional histological preparations and imaging techniques that limit exact morphometry of flight muscles. In this study, we employ microCT scanning on a tissue preparation that retains muscle morphology under homeostatic conditions. Focusing on a subset of IFMs called the dorsal longitudinal muscles (DLMs), we find that DLM volumes increase with age, partially due to the increased separation between myofibrillar fascicles, in a sex-dependent manner. We have uncovered and quantified asymmetry in the size of these muscles on either side of the longitudinal midline. Measurements of this resolution and scale make substantive studies that test the connection between form and function possible. We also demonstrate the application of this method to other insect species making it a valuable tool for histological analysis of insect biodiversity.

2019 ◽  
Author(s):  
Dhananjay Chaturvedi ◽  
Sunil Prabhakar ◽  
Aman Aggarwal ◽  
K VijayRaghavan

AbstractIndirect Flight Muscles (IFMs) in adult Drosophila have served as a valuable model for studying muscle development. In terms of function, they provide the key power stroke in adult insect flight. Variability in their architecture including of fiber numbers, shape and arrangement may provide insightful clues into adult muscle function. Conventional histological preparations in imaging techniques severely limit exact morphometric analysis of flight muscles, thereby impeding causal or correlative studies between muscle morphology and function. In this study we employ MicroCT scanning on a tissue preparation that retains muscle morphology under homeostatic conditions. We use this method to deliver precise measurements of a subset of IFMs, the Direct Longitudinal Muscles’ (DLMs) size and shape, in male and female Drosophila and changes therein, with age. Our findings reveal several unexpected characteristics of muscle fibers. We also demonstrate application to other insect species making it a valuable tool for histological analysis of insect biodiversity.Significance StatementAdult Drosophila muscles serve as models of homeostatic muscles. Accurate analysis of their form and function is key to understanding affects of genetic and physiological states on them. Recording adult muscle shape and volume has so far depended on protocols that inevitably distort tissue. Here, we use a MicroCT scanning based method that delivers changes in shape, size and organization between males and females, with time. This method is a significant step forward in recording muscle structure in situ with applications across species.


2020 ◽  
Vol 64 (1-2-3) ◽  
pp. 167-173
Author(s):  
Saroj Jawkar ◽  
Upendra Nongthomba

Myogenesis is a complex multifactorial process leading to the formation of the adult muscle. An amalgamation of autonomous processes including myoblast fusion and myofibrillogenesis, as well as non-autonomous processes, such as innervations from neurons and precise connections with attachment sites, are responsible for successful development and function of muscles. In this review, we describe the development of the indirect flight muscles (IFMs) in Drosophila melanogaster, and highlight the use of the IFMs as a model for studying muscle development and disease, based on recent studies on the development and function of IFMs.


2014 ◽  
Vol 88 (4) ◽  
pp. 633-635 ◽  
Author(s):  
Imran A. Rahman ◽  
Selena Y. Smith

‘Virtual paleontology’ entails the use of computational methods to assist in the three-dimensional (3-D) visualization and analysis of fossils, and has emerged as a powerful approach for research on the history of life. Three-dimensional imaging techniques allow poorly understood or previously unknown anatomies of fossil plants, invertebrates, and vertebrates, as well as microfossils and trace fossils, to be described in much greater detail than formerly possible, and are applicable to a wide range of preservation types and specimen sizes (Table 1). These methods include non-destructive high-resolution scanning technologies such as conventional X-ray micro-tomography and synchrotron-based X-ray tomography. In addition, form and function can be rigorously investigated through quantitative analysis of computer models, for example finite-element analysis.


2000 ◽  
Vol 151 (4) ◽  
pp. 945-950 ◽  
Author(s):  
Justine Kiessling ◽  
Sven Kruse ◽  
Stefan A. Rensing ◽  
Klaus Harter ◽  
Eva L. Decker ◽  
...  

It has been a long-standing dogma in life sciences that only eukaryotic organisms possess a cytoskeleton. Recently, this belief was questioned by the finding that the bacterial cell division protein FtsZ resembles tubulin in sequence and structure and, thus, may be the progenitor of this major eukaryotic cytoskeletal element. Here, we report two nuclear-encoded plant ftsZ genes which are highly conserved in coding sequence and intron structure. Both their encoded proteins are imported into plastids and there, like in bacteria, they act on the division process in a dose-dependent manner. Whereas in bacteria FtsZ only transiently polymerizes to a ring-like structure, in chloroplasts we identified persistent, highly organized filamentous scaffolds that are most likely involved in the maintenance of plastid integrity and in plastid division. As these networks resemble the eukaryotic cytoskeleton in form and function, we suggest the term “plastoskeleton” for this newly described subcellular structure.


Author(s):  
Shalini Menon ◽  
Dennis Goldfarb ◽  
Tsungyo Ho ◽  
Erica W. Cloer ◽  
Nicholas P. Boyer ◽  
...  

ABSTRACTTRIM9 and TRIM67 are neuronally-enriched E3 ubiquitin ligases essential for appropriate morphogenesis of cortical and hippocampal neurons and fidelitous responses to the axon guidance cue netrin-1. Deletion of murine Trim9 or Trim67 results in neuroanatomical defects and striking behavioral deficits, particularly in spatial learning and memory. TRIM9 and TRIM67 interact with cytoskeletal and exocytic proteins, but the full interactome is not known. Here we performed the unbiased proximity-dependent biotin identification (BioID) approach to define TRIM9 and TRIM67 protein-protein proximity network in developing cortical neurons and identified neuronal putative TRIM interaction partners. Candidates included cytoskeletal regulators, cytosolic protein transporters, exocytosis and endocytosis regulators, and proteins necessary for synaptic regulation. A subset of high priority candidates was validated, including Myo16, Coro1A, SNAP47, ExoC1, GRIP1, PRG-1, and KIF1A. For a subset of validated candidates, we utilized TIRF microscopy to demonstrate dynamic colocalization with TRIM proteins at the axonal periphery, including at the tips of filopodia. Further analysis demonstrated the RNAi-based knockdown of the unconventional myosin Myo16 in cortical neurons altered axonal branching patterns in a TRIM9 and netrin-1 dependent manner. Future analysis of other validated candidates will likely identify novel proteins and mechanisms by which TRIM9 and TRIM67 regulate neuronal form and function.


Development ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 215-227 ◽  
Author(s):  
J. Fernandes ◽  
K. VijayRaghavan

We have examined the development of innervation to the indirect flight muscles of Drosophila. During metamorphosis, the larval intersegmental nerve of the mesothorax is remodelled to innervate the dorsal longitudinal muscles and two of the dorsoventral muscles. Another modified larval nerve innervates the remaining dorsoventral muscle. The dorsal longitudinal muscles develop using modified larval muscles as templates while dorsoventral muscles develop without the use of such templates. The development of innervation to the two groups of indirect flight muscles differs in spatial and temporal patterns, which may reflect the different ways in which these muscles develop. The identification of myoblasts associated with thoracic nerves during larval life and the association of migrating myoblasts with nerves during metamorphosis indicate the existence of nerve-muscle interactions during indirect flight muscle development. In addition, the developing pattern of axonal branching suggests a role for the target muscles in respecifying neuromuscular junctions during metamorphosis.


2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Frank Stahnisch

AbstractIn theoretical accounts of the neurosciences, investigative research programs have often been separated into the morphological and physiological tradition. The morphological tradition is seen as describing the structure and form of the external and interior parts of the brain and spinal cord. The physiological tradition is interpreted as a compilation of those approaches which investigate cerebral functions particularly in their dynamic interactions. It must be regarded as an open question, though, whether the distinction between the morphological and physiological tradition in modern clinical and basic neuroscience has now become obsolete with the most recent neuroimaging techniques, such as fMRI, PET scans, SPECT, etc. Taken at face value, these new imaging techniques seem to relate, overlap, and even identify the anatomical with the functional substrate, when mapping individual patterns of neural activity across the visually delineated morphological structures. The particular focus of this review article is primarily on the morphological tradition, beginning with German neuroanatomist Samuel Thomas Soemmerring and leading to recent approaches in the neurohistological work of neuroscience centres in the United States and morphophysiological neuroimaging techniques in Canada. Following some landmark research steps in neuroanatomy detailed in the first section, this article analyzes the changing trajectories to an integrative theory of the brain in its second section. An examination of the relationship between form and function within the material culture of neuroscience in the third and final part, will further reveal an astonishingly heterogeneous investigative and conceptual terrain.


2018 ◽  
Author(s):  
Todd A. Schoborg ◽  
Samantha L. Smith ◽  
Lauren N. Smith ◽  
H. Douglas Morris ◽  
Nasser M. Rusan

ABSTRACTUnderstanding how events at the molecular and cellular scales contribute to tissue form and function is key to uncovering mechanisms driving animal development, physiology and disease. Elucidating these mechanisms has been enhanced through the study of model organisms and the use of sophisticated genetic, biochemical and imaging tools. Here we present an optimized method for non-invasive imaging of Drosophila melanogaster at high resolution using micro computed tomography (μ-CT). Our method allows for rapid processing of intact animals at any developmental stage, provides precise quantitative assessment of tissue size and morphology, and permits analysis of inter-organ relationships. We then use the power of μ-CT imaging to model human diseases through the characterization of microcephaly in the fly. Our work demonstrates that μ-CT is a versatile and accessible tool that complements standard imaging techniques, capable of uncovering novel biological mechanisms that have remained undocumented due to limitations of current methods.


Genes ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1982
Author(s):  
Guillaume Bordet ◽  
Niraj Lodhi ◽  
Andrew Kossenkov ◽  
Alexei Tulin

An individual’s gene expression profile changes throughout their life. This change in gene expression is shaped by differences in physiological needs and functions between the younger and older organism. Despite intensive studies, the aging process is not fully understood, and several genes involved in this process may remain to be identified. Here we report a transcriptomic analysis of Drosophila melanogaster using microarrays. We compared the expression profiles of two-day-old female adult flies with those of 45-day-old flies. We identified 1184 genes with pronounced differences in expression level between young and old age groups. Most genes involved in muscle development/maintenance that display different levels of expression with age were downregulated in older flies. Many of these genes contributed to sarcomere formation and function. Several of these genes were functionally related to direct and indirect flight muscles; some of them were exclusively expressed in these muscles. Conversely, several genes involved in apoptosis processes were upregulated in aging flies. In addition, several genes involved in resistance to toxic chemicals were upregulated in aging flies, which is consistent with a global upregulation of the defense response system in aging flies. Finally, we randomly selected 12 genes among 232 genes with unknown function and generated transgenic flies expressing recombinant proteins fused with GFP protein to determine their subcellular expression. We also found that the knockdown of some of those 12 genes can affect the lifespan of flies.


BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Talia M. Lowi-Merri ◽  
Roger B. J. Benson ◽  
Santiago Claramunt ◽  
David C. Evans

Abstract Background The origin of powered avian flight was a locomotor innovation that expanded the ecological potential of maniraptoran dinosaurs, leading to remarkable variation in modern birds (Neornithes). The avian sternum is the anchor for the major flight muscles and, despite varying widely in morphology, has not been extensively studied from evolutionary or functional perspectives. We quantify sternal variation across a broad phylogenetic scope of birds using 3D geometric morphometrics methods. Using this comprehensive dataset, we apply phylogenetically informed regression approaches to test hypotheses of sternum size allometry and the correlation of sternal shape with both size and locomotory capabilities, including flightlessness and the highly varying flight and swimming styles of Neornithes. Results We find evidence for isometry of sternal size relative to body mass and document significant allometry of sternal shape alongside important correlations with locomotory capability, reflecting the effects of both body shape and musculoskeletal variation. Among these, we show that a large sternum with a deep or cranially projected sternal keel is necessary for powered flight in modern birds, that deeper sternal keels are correlated with slower but stronger flight, robust caudal sternal borders are associated with faster flapping styles, and that narrower sterna are associated with running abilities. Correlations between shape and locomotion are significant but show weak explanatory power, indicating that although sternal shape is broadly associated with locomotory ecology, other unexplored factors are also important. Conclusions These results display the ecological importance of the avian sternum for flight and locomotion by providing a novel understanding of sternum form and function in Neornithes. Our study lays the groundwork for estimating the locomotory abilities of paravian dinosaurs, the ancestors to Neornithes, by highlighting the importance of this critical element for avian flight, and will be useful for future work on the origin of flight along the dinosaur-bird lineage.


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