scholarly journals The evolution of insect metamorphosis: a developmental and endocrine view

2019 ◽  
Vol 374 (1783) ◽  
pp. 20190070 ◽  
Author(s):  
James W. Truman ◽  
Lynn M. Riddiford
Keyword(s):  
Transcription Factors ◽  
Experimental Treatment ◽  
The Other ◽  
Life Stages ◽  
Developmental Genetic ◽  
Theme Issue ◽  
Insect Metamorphosis ◽  
Krüppel Homolog 1 ◽  
Complete Metamorphosis ◽  
Insight Into

Developmental, genetic and endocrine data from diverse taxa provide insight into the evolution of insect metamorphosis. We equate the larva–pupa–adult of the Holometabola to the pronymph–nymph–adult of hemimetabolous insects. The hemimetabolous pronymph is a cryptic embryonic stage with unique endocrinology and behavioural modifications that probably served as preadaptations for the larva. It develops in the absence of juvenile hormone (JH) as embryonic primordia undergo patterning and morphogenesis, the processes that were arrested for the evolution of the larva. Embryonic JH then drives tissue differentiation and nymph formation. Experimental treatment of pronymphs with JH terminates patterning and induces differentiation, mimicking the processes that occurred during the evolution of the larva. Unpatterned portions of primordia persist in the larva, becoming imaginal discs that form pupal and adult structures. Key transcription factors are associated with the holometabolous life stages: Krüppel-homolog 1 ( Kr-h1 ) in the larva, broad in the pupa and E93 in the adult. Kr-h1 mediates JH action and is found whenever JH acts, while the other two genes direct the formation of their corresponding stages. In hemimetabolous forms, the pronymph has low Broad expression, followed by Broad expression through the nymphal moults, then a switch to E93 to form the adult. This article is part of the theme issue ‘The evolution of complete metamorphosis’.

The early epaxial enhancer is essential for the initial expression of the skeletal muscle determination geneMyf5but not for subsequent, multiple phases of somitic myogenesis

Development ◽  
2002 ◽  
Vol 129 (19) ◽  
pp. 4571-4580 ◽  
Author(s):  
Lydia Teboul ◽  
Juliette Hadchouel ◽  
Philippe Daubas ◽  
Dennis Summerbell ◽  
Margaret Buckingham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Transcription Factors ◽  
Regulatory Element ◽  
Regulatory Elements ◽  
The Other ◽  
Myogenic Regulatory Factors ◽  
Reporter Construct ◽  
Mouse Development ◽  
Insight Into

Vertebrate myogenesis is controlled by four transcription factors known as the myogenic regulatory factors (MRFs): Myf5, Mrf4, myogenin and MyoD. During mouse development Myf5 is the first MRF to be expressed and it acts by integrating multiple developmental signals to initiate myogenesis. Numerous discrete regulatory elements are involved in the activation and maintenance of Myf5 gene expression in the various muscle precursor populations, reflecting the diversity of the signals that control myogenesis. Here we focus on the enhancer that recapitulates the first phase of Myf5 expression in the epaxial domain of the somite, in order to identify the subset of cells that first transcribes the gene and therefore gain insight into molecular, cellular and anatomical facets of early myogenesis. Deletion of this enhancer from a YAC reporter construct that recapitulates the Myf5 expression pattern demonstrates that this regulatory element is necessary for expression in the early epaxial somite but in no other site of myogenesis. Importantly, Myf5 is subsequently expressed in the epaxial myotome under the control of other elements located far upstream of the gene. Our data suggest that the inductive signals that control Myf5 expression switch rapidly from those that impinge on the early epaxial enhancer to those that impinge on the other enhancers that act later in the epaxial somite, indicating that there are significant changes in either the signalling environment or the responsiveness of the cells along the rostrocaudal axis. We propose that the first phase of Myf5 epaxial expression, driven by the early epaxial enhancer in the dermomyotome, is necessary for early myotome formation, while the subsequent phases are associated with cytodifferentiation within the myotome.

scholarly journals Complete metamorphosis of insects

2019 ◽  
Vol 374 (1783) ◽  
pp. 20190063 ◽  
Author(s):  
Jens Rolff ◽  
Paul R. Johnston ◽  
Stuart Reynolds
Keyword(s):  
Adult Stage ◽  
Pupal Stage ◽  
Life Stages ◽  
Micro Ct ◽  
Larval Form ◽  
Theme Issue ◽  
The Cost ◽  
Ephemeral Resources ◽  
Complete Metamorphosis

The majority of described hexapod species are holometabolous insects, undergoing an extreme form of metamorphosis with an intercalated pupal stage between the larva and adult, in which organs and tissues are extensively remodelled and in some cases completely rebuilt. Here, we review how and why this developmental strategy has evolved. While there are many theories explaining the evolution of metamorphosis, many of which fit under the hypothesis of decoupling of life stages, there are few clear adaptive hypotheses on why complete metamorphosis evolved. We propose that the main adaptive benefit of complete metamorphosis is decoupling between growth and differentiation. This facilitates the exploitation of ephemeral resources and enhances the probability of the metamorphic transition escaping developmental size thresholds. The evolution of complete metamorphosis comes at the cost of exposure to predators, parasites and pathogens during pupal life and requires specific adaptations of the immune system at this time. Moreover, metamorphosis poses a challenge for the maintenance of symbionts and the gut microbiota, although it may also offer the benefit of allowing an extensive change in microbiota between the larval and adult stages. The regulation of metamorphosis by two main players, ecdysone and juvenile hormone, and the related signalling cascades are now relatively well understood. The mechanics of metamorphosis have recently been studied in detail because of the advent of micro-CT and research into the role of cell death in remodelling tissues and organs. We support the argument that the adult stage must necessarily have preceded the larval form of the insect. We do not resolve the still contentious question of whether the larva of insects in general originated through the modification of existing preadult forms or through heterochrony as a modified embryonic stage (pronymph), nor whether the holometabolous pupa arose as a modified hemimetabolous final stage larva. This article is part of the theme issue ‘The evolution of complete metamorphosis’.

scholarly journals Visualization of insect metamorphosis

2019 ◽  
Vol 374 (1783) ◽  
pp. 20190071 ◽  
Author(s):  
Martin J. R. Hall ◽  
Daniel Martín-Vega
Keyword(s):  
Model Organism ◽  
Micro Computed Tomography ◽  
Medical Sciences ◽  
Theme Issue ◽  
The Past ◽  
Primary Model ◽  
Insect Metamorphosis ◽  
Non Destructive ◽  
Complete Metamorphosis

Metamorphosis and, in particular, holometaboly, the development of organisms through a series of discrete stages (egg, larva, pupa, adult) that hardly resemble one another but are finely adapted to specific roles in the life cycle of the organism, has fascinated and mystified humans throughout history. However, it can be difficult to visualize the dramatic changes that occur during holometaboly without destructive sampling, traditionally through histology. However, advances in imaging technologies developed mainly for medical sciences have been applied to studies of insect metamorphosis over the past couple of decades. These include micro-computed tomography, magnetic resonance imaging and optical coherence tomography. A major advantage of these techniques is that they are rapid and non-destructive, enabling virtual dissection of an organism in any plane by anyone who has access to the image files and the necessary software. They can also be applied in some cases to visualize metamorphosis in vivo , including the periods of most rapid and dramatic morphological change. This review focusses on visualizing the intra-puparial holometabolous metamorphosis of cyclorraphous flies (Diptera), including the primary model organism for all genetic investigations, Drosophila melanogaster , and the blow flies of medical, veterinary and forensic importance, but also discusses similar studies on other insect orders. This article is part of the theme issue ‘The evolution of complete metamorphosis’.

A Bird in the Hand Isn’t Good for Long

2018 ◽  
Vol 65 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Stefan Scherbaum ◽  
Simon Frisch ◽  
Maja Dshemuchadse
Keyword(s):  
Decision Making ◽  
Cognitive Control ◽  
The Other ◽  
Decision Task ◽  
Short Term ◽  
Additional Time ◽  
Control Processes ◽  
Folk Wisdom ◽  
Study Participants ◽  
Insight Into

Abstract. Folk wisdom tells us that additional time to make a decision helps us to refrain from the first impulse to take the bird in the hand. However, the question why the time to decide plays an important role is still unanswered. Here we distinguish two explanations, one based on a bias in value accumulation that has to be overcome with time, the other based on cognitive control processes that need time to set in. In an intertemporal decision task, we use mouse tracking to study participants’ responses to options’ values and delays which were presented sequentially. We find that the information about options’ delays does indeed lead to an immediate bias that is controlled afterwards, matching the prediction of control processes needed to counter initial impulses. Hence, by using a dynamic measure, we provide insight into the processes underlying short-term oriented choices in intertemporal decision making.

Correlational Methods for Analysis of Dance Movements

2011 ◽  
Vol 29 (supplement) ◽  
pp. 283-304 ◽  
Author(s):  
Timothy R. Brick ◽  
Steven M. Boker
Keyword(s):  
Motion Capture ◽  
Mirror Symmetry ◽  
Cross Correlation ◽  
The Other ◽  
Free Form ◽  
Motion Capture Data ◽  
Complex Interactions ◽  
Dance Movements ◽  
Time Lagged ◽  
Insight Into

Among the qualities that distinguish dance from other types of human behavior and interaction are the creation and breaking of synchrony and symmetry. The combination of symmetry and synchrony can provide complex interactions. For example, two dancers might make very different movements, slowing each time the other sped up: a mirror symmetry of velocity. Examining patterns of synchrony and symmetry can provide insight into both the artistic nature of the dance, and the nature of the perceptions and responses of the dancers. However, such complex symmetries are often difficult to quantify. This paper presents three methods – Generalized Local Linear Approximation, Time-lagged Autocorrelation, and Windowed Cross-correlation – for the exploration of symmetry and synchrony in motion-capture data as is it applied to dance and illustrate these with examples from a study of free-form dance. Combined, these techniques provide powerful tools for the examination of the structure of symmetry and synchrony in dance.

Marx, Silk Poems, and the Pretext of Qualities

2020 ◽  
Vol 151 (1) ◽  
pp. 96-126
Author(s):  
Kathryn Crim
Keyword(s):  
The Other ◽  
Use Value ◽  
Working Day ◽  
The One ◽  
Insight Into

Karl Marx’s comments on silk manufacture in “The Working Day” chapter of Capital, volume 1, demonstrate how “quality”—usually associated with “use value”—has been mobilized by capital to naturalize industrialized labor. Putting his insight into conversation with a recent multimedia poetic project, Jen Bervin’s Silk Poems (2016–17), this essay examines the homology between, on the one hand, poetry’s avowed task of fitting form to content and, on the other, the ideology of labor that fits specific bodies to certain materials and tasks.

Spiritualism in Raymond Carver’s Work

2015 ◽  
Vol 3 (1) ◽  
pp. 214
Author(s):  
Viola Kita
Keyword(s):  
The Other ◽  
Good Thing ◽  
Raymond Carver ◽  
The Bible ◽  
Other Hand ◽  
Christian Writer ◽  
Spiritual Reading ◽  
Insight Into

Raymond Carver’s work provides the opportunity for a spiritual reading. The article that offers the greatest insight into spirituality is William Stull’s “Beyond Hopelessville: Another Side of Raymond Carver.” In it we can notice the darkness which is dominant in Carver’s early works with the optimism that is an essential part of Carver’s work “Cathedral”. A careful reading of “A Small Good Thing” and “The Bath” can give the idea that they are based on the allegory of spiritual rebirth which can be interpreted as a “symbol of Resurrection”. Despite Stull’s insisting in Carver’s stories allusions based on the Bible, it cannot be proved that the writer has made use of Christian imagery. Therefore, it can be concluded that spirituality in Carver’s work is one of the most confusing topics so far in the literary world because on one hand literary critics find a lot of biblical elements and on the other hand Carver himself refuses to be analyzed as a Christian writer.

Intimacy as Transgression and the Problem of Freedom

2018 ◽  
Vol 1 (1) ◽  
pp. 18
Author(s):  
Kym Maclaren
Keyword(s):  
Intimate Relationships ◽  
Critical Analysis ◽  
Mutual Recognition ◽  
Public Institutions ◽  
The Other ◽  
Social Forces ◽  
Critical Insight ◽  
Insight Into ◽  
What Matters

“To consent to love or be loved,” said Merleau-Ponty, “is to consent also to influence someone else, to decide to a certain extent on behalf of the other.” This essay explicates that idea through a meditation on intimacy. I propose, first, that, on Merleau-Ponty’s account, we are always transgressing into each other’s experience, whether we are strangers or familiars; I call this “ontological intimacy.” Concrete experiences of intimacy are based upon this ontological intimacy, and can take place at two levels: (1) at-this-moment (such that we can experience intimacy even with strangers, by sharing a momentary but extra-ordinary mutual recognition) and (2) in shared interpersonal institutions, or habitual, enduring, and co-enacted visions of who we are, how to live, and what matters. Through particular examples of dynamics within these layers of intimacy (drawing upon work by Berne and by Russon), I claim that we are always, inevitably, imposing an “unfreedom” upon our intimate others. Freedom, then, can only develop from within and by virtue of this “unfreedom.” Thus, what distinguishes empowering or emancipating relationships from oppressive ones is not the removal of transgressive normative social forces; it is rather the particular character of those transgressive forces. Some transgressions upon others’ experience—some forms of “unfreedom”—will tend to promote freedom; others will tend to hinder it. This amounts to a call for promoting agency and freedom not only through critical analysis of public institutions, practices and discourses, but also through critical insight into and transformation of our most private and intimate relationships.

Basic Concepts and Definitions of Allergology

2019 ◽  
Author(s):  
Zoran Vrucinic
Keyword(s):  
Immune Reaction ◽  
The Body ◽  
The Other ◽  
Specific Response ◽  
Other Hand ◽  
Medical Vocabulary ◽  
The Future ◽  
Basic Concepts ◽  
Basic Insight ◽  
Insight Into

The future of medicine belongs to immunology and alergology. I tried to not be too wide in description, but on the other hand to mention the most important concepts of alergology to make access to these diseases more understandable, logical and more useful for our patients, that without complex pathophysiology and mechanism of immune reaction,we gain some basic insight into immunological principles. The name allergy to medicine was introduced by Pirquet in 1906, and is of Greek origin (allos-other + ergon-act; different reaction), essentially representing the reaction of an organism to a substance that has already been in contact with it, and manifested as a specific response thatmanifests as either a heightened reaction, a hypersensitivity, or as a reduced reaction immunity. Synonyms for hypersensitivity are: altered reactivity, reaction, hypersensitivity. The word sensitization comes from the Latin (sensibilitas, atis, f.), which means sensibility,sensitivity, and has retained that meaning in medical vocabulary, while in immunology and allergology this term implies the creation of hypersensitivity to an antigen. Antigen comes from the Greek words, anti-anti + genos-genus, the opposite, anti-substance substance that causes the body to produce antibodies.

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