Development of the Drosophila tracheal system occurs by a series of morphologically distinct but genetically coupled branching events

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1395-1407 ◽  
Author(s):  
C. Samakovlis ◽  
N. Hacohen ◽  
G. Manning ◽  
D.C. Sutherland ◽  
K. Guillemin ◽  
...  
Keyword(s):  
Tube Formation ◽  
The Body ◽  
Terminal Branch ◽  
Cellular Mechanisms ◽  
Morphological Marker ◽  
Tracheal System ◽  
Fgf Receptor ◽  
Restricted Domains ◽  
Gene Regulatory ◽  
Ets Domain

The tracheal (respiratory) system of Drosophila melanogaster is a branched network of epithelial tubes that ramifies throughout the body and transports oxygen to the tissues. It forms by a series of sequential branching events in each hemisegment from T2 to A8. Here we present a cellular and initial genetic analysis of the branching process. We show that although branching is sequential it is not iterative. The three levels of branching that we distinguish involve different cellular mechanisms of tube formation. Primary branches are multicellular tubes that arise by cell migration and intercalation; secondary branches are unicellular tubes formed by individual tracheal cells; terminal branches are subcellular tubes formed within long cytoplasmic extensions. Each level of branching is accompanied by expression of a different set of enhancer trap markers. These sets of markers are sequentially activated in progressively restricted domains and ultimately individual tracheal cells that are actively forming new branches. A clonal analysis demonstrates that branching fates are not assigned to tracheal cells until after cell division ceases and branching begins. We further show that the breathless FGF receptor, a tracheal gene required for primary branching, is also required to activate expression of markers involved in secondary branching and that the pointed ETS-domain transcription factor is required for secondary branching and also to activate expression of terminal branch markers. The combined morphological, marker expression and genetic data support a model in which successive branching events are mechanistically and genetically distinct but coupled through the action of a tracheal gene regulatory hierarchy.

Pressure cycles and the water economy of insects

1988 ◽  
Vol 318 (1190) ◽  
pp. 377-407 ◽  
Keyword(s):  
Body Temperature ◽  
Water Exchange ◽  
Vapour Phase ◽  
The Body ◽  
Tracheal System ◽  
Water Economy ◽  
Insect Wings ◽  
Pressure Cycle ◽  
Respiratory Gases

Water exchange between insects and their environment via the vapour phase includes influx and efflux components. The pressure cycle theory postulates that insects (and some other arthropods) can regulate the relative rates of influx and efflux of water vapour by modulating hydrostatic pressures at a vapour-liquid interface by compressing or expanding a sealed, gas-filled cavity. Some such cavities, like the tracheal system, could be compressed by elevated pressure in all or part of the haemocoele. Others, perhaps including the muscular rectum of flea prepupae, could be compressed by intrinsic muscles. Maddrell Insect Physiol . 8, 199 (1971)) suggested a pressure cycle mechanism of this kind to account for rectal uptake of water vapour in Thermobia but did not find it compatible with quantitative information then available. Newer evidence conforms better with the proposed mechanism. Cyclical pressure changes are of widespread occurrence in insects and have sometimes been shown to depend on water status. Evidence is reviewed for the role of the tracheal system as an avenue for net exchange of water between the insect and its environment. Because water and respiratory gases share common pathways, most published findings fail to distinguish between the conventional view that the tracheal system has evolved as a site for distribution and exchange of respiratory gases and that any water exchange occurring in it is generally incidental and nonadaptive, and the theory proposed here. The pressure cycle theory offers a supplementary explanation not incompatible with evidence so far available. The relative importance of water economy and respiratory exchange in the functioning of compressible cavities such as the tracheal system remains to be explored. Some further implications of the pressure cycle theory are discussed. Consideration is given to the possible involvement of vapour-phase transport in the internal redistribution of water within the body. It is suggested that some insect wings may constitute internal vapour-liquid exchange sites, where water can move from the body fluids to the intratracheal gas. Ambient and body temperature must influence rates of vapour-liquid mass transfer. If elevated body temperature promotes evaporative discharge of the metabolic water burden that has been shown to accumulate during flight in some large insects, their minimum threshold thoracic temperature for sustained flight may relate to the maintenance of water balance. The role of water economy in the early evolution of insect wings is considered. Pressure cycles might help to maintain water balance in surface-breathing insects living in fresh and saline waters, but the turbulence of the surface of the open sea might prevent truly marine forms from using this mechanism.

scholarly journals Combined surgical treatment of arteriovenous malformation of the lower jaw

2020 ◽  
Vol 34 (4) ◽  
pp. 95-104
Author(s):  
D.V. Shchehlov ◽  
V.M. Zahorodnii ◽  
I.V. Altman ◽  
N.V. Kiselyova ◽  
I.I. Kashkish
Keyword(s):  
Arteriovenous Malformation ◽  
Cerebral Angiography ◽  
Combined Treatment ◽  
The Body ◽  
Facial Artery ◽  
External Carotid ◽  
Maxillary Artery ◽  
Terminal Branch ◽  
Lower Jaw ◽  
The Right

The objective – to presents the observation of combined treatment of a patient with arteriovenous malformation of the lower jaw.A man, 21 years old, was hospitalized in the Scientific-Practical Center of Endovascular Neuroradiology NAMS of Ukraine with complaints of bleeding from a tooth socket after an attempt to remove the 6th tooth (first painter) of the lower jaw on the left. According to the performed survey radiography of the lower jaw, an aneurysmal bone cyst was revealed in the body of the lower jaw on the left, corresponding to the localization of bleeding. According to cerebral angiography, an arteriovenous malformation of the lower jaw was revealed on the left, the afferent arteries of which were: the right facial artery (a branch of the right external carotid artery (ECA)), the left facial artery (a branch of the left ECA), the lower alveolar artery, the superior-posterior alveolar artery (branches of the maxillary artery ‒ the terminal branch of the left ECA) with drainage into a vein, which was located in the body of the lower jaw. In order to exclude the malformation from the bloodstream and prevent bleeding, a controlled embolization of the malformation was performed using non-spherical emboli – polyvinyl alcohol (PVA) particles from Cook, USA. Using a transfemoral approach, a guide catheter was inserted into the orifice of the ECA, then a Headway 27 microcatheter (Microvention, USA) was passed through it along a Traxes 14 guide wire (Microvention, USA), the afferent arteries of the malformation were selectively cathete-rized in turn, and embolization was performed after superselective angiography. The patient was discharged in a satisfactory condition. Two weeks after the operation, the bleeding resumed. The performed control cerebral angiography revealed a relapse of the malformation with a change in its angioarchitectonics ‒ the filling of the malformation in the late arterial and venous phases of cerebral blood flow was noted. Re-embolization was performed using PVA emboli (Cook), which was supplemented by transcutaneous puncture of the drainage vein in the mandible and its embolization with histoacryl (B. Braun, Germany) and lipiodol (Guerbet, France) in a 1 : 1 ratio. Results. As a result of using this technique, it was possible to turn off the malformation completely. For 6 months from the moment of surgery, no bleeding was noted, and subsequently the patient had a tooth removed without complications.Conclusions. The proposed method for treating arteriovenous malformation of the lower jaw, proposed in this case, showed the effectiveness of a combination of endovascular embolization in combination with transcutaneous embolization of the draining vein and can be successfully used to treat this pathology.

scholarly journals Splenic Mechanisms of Thrombocytopenia

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-33-SCI-33
Author(s):  
John W. Semple
Keyword(s):  
Immune Responses ◽  
Reticuloendothelial System ◽  
Lymphoid Organ ◽  
The Body ◽  
White Pulp ◽  
Cellular Mechanisms ◽  
Venous Circulation ◽  
Destructive Processes ◽  
Clinical Conditions ◽  
Red Pulp

The spleen is the largest secondary lymphoid organ in the body and contains up to 25 percent of the body's lymphocyte populations. It is not only responsible for initiating immune responses against a multitude of infectious antigens within its white pulp, it also has the exquisite ability to filter the blood and remove, for example, senescent erythrocytes and platelets. This natural process is carried out within the red pulp of the spleen which is composed monocyte-rich connective tissue cords of Billroth intertwined with sinus cavities lined by parallel-oriented endothelial cells that have interendothelial slits which allow for the mechanical sorting of "old" cells. This occurs because of the inability of the senescent cells to properly migrate through the endothelial fenestrae into the venous circulation allowing them to be identified by cells of the reticuloendothelial system (RES) and quickly destroyed by phagocytosis. This process also allows for the efficient recycling of iron from destroyed erythrocyte hemoglobin molecules. There are a wide variety of clinical conditions that can significantly alter the ability of the RES to destroy blood cells including hereditary blood cell defects, inflammation, cancer and abnormal immune responses. This lecture will focus on the central role that the spleen plays in not only generating immune responses against platelets but also in primarily causing the destruction of both senescent and antibody-opsonized platelets leading to thrombocytopenia. It will discuss the soluble and cellular mechanisms of splenic sequestration, destruction and the ability of the spleen to modulate anti-platelet immunity. Mechanisms involving complement activation, Fc Receptor-mediated phagocytosis, antibody dependent cellular cytotoxicity and platelet self-destruction will be addressed. It will compare the spleen's platelet destructive capabilities with other organs, particularly the liver and will detail how immune responses generated in the white pulp can modulate platelet destructive processes in the red pulp. Disclosures Semple: Amgen: Consultancy, Honoraria, Speakers Bureau; Rigel: Consultancy, Honoraria; UCB: Consultancy, Honoraria.

The Evaporation of Water from the Cockroach

1935 ◽  
Vol 12 (4) ◽  
pp. 373-383 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Wind Velocity ◽  
Body Surface ◽  
Periplaneta Americana ◽  
The Body ◽  
Tracheal System ◽  
Physical Systems ◽  
Change Of State ◽  
Fatty Substance ◽  
Effects Of Temperature ◽  
Rate Of Evaporation

1. The effects of temperature, humidity and wind velocity upon the rate of evaporation of water from the cockroach Periplaneta americana have been studied. 2. The effects of these factors upon the rate of evaporation from the tracheal system are shown to be similar to their effects upon purley physical systems. 3. The effects of these factors upon the rate of evaporation from the body surface are shown to be complicated by the presence of a film of fatty substance which undergoes a change of state at about 30° C.

Heartbroken is a specific downstream mediator of FGF receptor signalling in Drosophila

Development ◽  
1998 ◽  
Vol 125 (22) ◽  
pp. 4379-4389 ◽  
Author(s):  
A.M. Michelson ◽  
S. Gisselbrecht ◽  
E. Buff ◽  
J.B. Skeath
Keyword(s):  
Egf Receptor ◽  
Genetic Interaction ◽  
Egf Receptors ◽  
Tracheal System ◽  
Fgf Receptor ◽  
Receptor Signalling ◽  
Early Migration ◽  
New Gene ◽  
Developmental Responses ◽  
Downstream Mediator

Drosophila possesses two FGF receptors which are encoded by the heartless and breathless genes. HEARTLESS is essential for early migration and patterning of the embryonic mesoderm, while BREATHLESS is required for proper branching of the tracheal system. We have identified a new gene, heartbroken, that participates in the signalling pathways of both FGF receptors. Mutations in heartbroken are associated with defects in the migration and later specification of mesodermal and tracheal cells. Genetic interaction and epistasis experiments indicate that heartbroken acts downstream of the two FGF receptors but either upstream of or parallel to RAS1. Furthermore, heartbroken is involved in both the HEARTLESS- and BREATHLESS-dependent activation of MAPK. In contrast, EGF receptor-dependent embryonic functions and MAPK activation are not perturbed in heartbroken mutant embryos. A strong heartbroken allele also suppresses the effects of hyperactivated FGF but not EGF receptors. Thus, heartbroken may contribute to the specificity of developmental responses elicited by FGF receptor signalling.

A Mechanistic Motor-Clutch Model That Explains Cell Shape Dynamics to Cyclic Stretch

2022 ◽  
Author(s):  
Benjamin W. Scandling ◽  
Jia Gou ◽  
Jessica Thomas ◽  
Jacqueline Xuan ◽  
Chuan Xue ◽  
...  
Keyword(s):  
Computational Model ◽  
Computational Models ◽  
The Body ◽  
Cyclic Stretch ◽  
Substrate Stiffness ◽  
Cell Alignment ◽  
Cellular Mechanisms ◽  
Actin Bundles ◽  
The Impact

Many cells in the body experience cyclic mechanical loading, which can impact cellular processes and morphology. In vitro studies often report that cells reorient in response to cyclic stretch of their substrate. To explore cellular mechanisms involved in this reorientation, a computational model was developed by utilizing the previous computational models of the actin-myosin-integrin motor-clutch system developed by others. The computational model predicts that under most conditions, actin bundles align perpendicular to the direction of applied cyclic stretch, but under specific conditions, such as low substrate stiffness, actin bundles align parallel to the direction of stretch. The model also predicts that stretch frequency impacts the rate of reorientation, and that proper myosin function is critical in the reorientation response. These computational predictions are consistent with reports from the literature and new experimental results presented here. The model suggests that the impact of different stretching conditions (stretch type, amplitude, frequency, substrate stiffness, etc.) on the direction of cell alignment can largely be understood by considering their impact on cell-substrate detachment events, specifically whether detachment occurs during stretching or relaxing of the substrate.

scholarly journals Versatility of Induced Pluripotent Stem Cells (iPSCs) for Improving the Knowledge on Musculoskeletal Diseases

2020 ◽  
Vol 21 (17) ◽  
pp. 6124
Author(s):  
Clara Sanjurjo-Rodríguez ◽  
Rocío Castro-Viñuelas ◽  
María Piñeiro-Ramil ◽  
Silvia Rodríguez-Fernández ◽  
Isaac Fuentes-Boquete ◽  
...  
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Disease Modeling ◽  
Musculoskeletal Diseases ◽  
The Body ◽  
Cellular Mechanisms ◽  
Induced Pluripotent ◽  
New Strategies

Induced pluripotent stem cells (iPSCs) represent an unlimited source of pluripotent cells capable of differentiating into any cell type of the body. Several studies have demonstrated the valuable use of iPSCs as a tool for studying the molecular and cellular mechanisms underlying disorders affecting bone, cartilage and muscle, as well as their potential for tissue repair. Musculoskeletal diseases are one of the major causes of disability worldwide and impose an important socio-economic burden. To date there is neither cure nor proven approach for effectively treating most of these conditions and therefore new strategies involving the use of cells have been increasingly investigated in the recent years. Nevertheless, some limitations related to the safety and differentiation protocols among others remain, which humpers the translational application of these strategies. Nonetheless, the potential is indisputable and iPSCs are likely to be a source of different types of cells useful in the musculoskeletal field, for either disease modeling or regenerative medicine. In this review, we aim to illustrate the great potential of iPSCs by summarizing and discussing the in vitro tissue regeneration preclinical studies that have been carried out in the musculoskeletal field by using iPSCs.

scholarly journals In vivo continuous three-dimensional magnetic resonance microscopy: a study of metamorphosis in Carniolan worker honey bees (Apis mellifera carnica)

2020 ◽  
Vol 223 (21) ◽  
pp. jeb225250
Author(s):  
Aleš Mohorič ◽  
Janko Božič ◽  
Polona Mrak ◽  
Kaja Tušar ◽  
Chenyun Lin ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Magnetic Resonance ◽  
Time Course ◽  
Three Dimensional ◽  
The Body ◽  
Magnetic Resonance Microscopy ◽  
Tracheal System ◽  
Apis Mellifera Carnica ◽  
Occurrence Matrix

ABSTRACTThree-dimensional (3D) magnetic resonance microscopy (MRM) is a modality of magnetic resonance imaging (MRI) optimized for the best resolution. Metamorphosis of the Carniolan worker honey bee (Apis mellifera carnica) was studied in vivo under controlled temperature and humidity conditions from sealed larvae until the emergence of an adult. The 3D images were analyzed by volume rendering and segmentation, enabling the analysis of the body, tracheal system and gastrointestinal tract through the time course of volume changes. Fat content sensitivity enabled the analysis of flight muscles transformation during the metamorphosis by the signal histogram and gray level co-occurrence matrix (GLCM). Although the transformation during metamorphosis is well known, MRM enables an alternative insight to this process, i.e. 3D in vivo, which has relatively high spatial and temporal resolutions. The developed methodology can easily be adapted for studying the metamorphosis of other insects or any other incremental biological process on a similar spatial and temporal scale.

scholarly journals Cholera toxin enhances Na+absorption across MCF10A human mammary epithelia

2014 ◽  
Vol 306 (5) ◽  
pp. C471-C484 ◽  
Author(s):  
Qian Wang ◽  
Bruce D. Schultz
Keyword(s):  
Ion Transport ◽  
Cholera Toxin ◽  
Short Circuit ◽  
Mammary Epithelium ◽  
Brefeldin A ◽  
Short Circuit Current ◽  
The Body ◽  
Cellular Mechanisms ◽  
Mammary Epithelia ◽  
Mcf10a Cells

Cellular mechanisms to account for the low Na+concentration in human milk are poorly defined. MCF10A cells, which were derived from human mammary epithelium and grown on permeable supports, exhibit amiloride- and benzamil-sensitive short-circuit current ( Isc; a sensitive indicator of net ion transport), suggesting activity of the epithelial Na+channel ENaC. When cultured in the presence of cholera toxin (Ctx), MCF10A cells exhibit greater amiloride-sensitive Iscat all time points tested (2 h to 7 days), an effect that is not reduced with Ctx washout for 12 h. Amiloride-sensitive Iscremains elevated by Ctx in the presence of inhibitors for PKA (H-89, Rp-cAMP), PI3K (LY294002), and protein trafficking (brefeldin A). Additionally, the Ctx B subunit, alone, does not replicate these effects. RT-PCR and Western blot analyses indicate no significant increase in either the mRNA or protein expression for α-, β-, or, γ-ENaC subunits. Ctx increases the abundance of both β- and γ-ENaC in the apical membrane. Additionally, Ctx increases both phosphorylated and nonphosphorylated Nedd4-2 expression. These results demonstrate that human mammary epithelia express ENaC, which can account for the low Na+concentration in milk. Importantly, the results suggest that Ctx increases the expression but reduces the activity of the E3 ubiquitin ligase Nedd4-2, which would tend to reduce the ENaC retrieval and increase steady-state membrane residency. The results reveal a novel mechanism in human mammary gland epithelia by which Ctx regulates ENaC-mediated Na+transport, which may have inferences for epithelial ion transport regulation in other tissues throughout the body.

Dynamics of tracheal compression in the horned passalus beetle

2013 ◽  
Vol 304 (8) ◽  
pp. R621-R627 ◽  
Author(s):  
James S. Waters ◽  
Wah-Keat Lee ◽  
Mark W. Westneat ◽  
John J. Socha
Keyword(s):  
Dynamical Behavior ◽  
The Body ◽  
Reverse Direction ◽  
Effective Diameter ◽  
Contrast Imaging ◽  
Tracheal System ◽  
Tracheal Compression ◽  
Internal Mixing ◽  
Respiratory Gases ◽  
Opening And Closing

Rhythmic patterns of compression and reinflation of the thin-walled hollow tubes of the insect tracheal system have been observed in a number of insects. These movements may be important for facilitating the transport and exchange of respiratory gases, but observing and characterizing the dynamics of internal physiological systems within live insects can be challenging due to their size and exoskeleton. Using synchrotron X-ray phase-contrast imaging, we observed dynamical behavior in the tracheal system of the beetle, Odontotaenius disjunctus. Similar to observations of tracheal compression in other insects, specific regions of tracheae in the thorax of O. disjunctus exhibit rhythmic collapse and reinflation. During tracheal compression, the opposing sides of a tracheal tube converge, causing the effective diameter of the tube to decrease. However, a unique characteristic of tracheal compression in this species is that certain tracheae collapse and reinflate with a wavelike motion. In the dorsal cephalic tracheae, compression begins anteriorly and continues until the tube is uniformly flattened; reinflation takes place in the reverse direction, starting with the posterior end of the tube and continuing until the tube is fully reinflated. We report the detailed kinematics of this pattern as well as additional observations that show tracheal compression coordinated with spiracle opening and closing. These findings suggest that tracheal compression may function to drive flow within the body, facilitating internal mixing of respiratory gases and ventilation of distal regions of the tracheal system.

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