scholarly journals Patterning Muscles Using Organizers: Larval Muscle Templates and Adult Myoblasts Actively Interact to Pattern the Dorsal Longitudinal Flight Muscles of Drosophila

1998 ◽  
Vol 141 (5) ◽  
pp. 1135-1145 ◽  
Author(s):  
Sudipto Roy ◽  
K. VijayRaghavan
Keyword(s):  
Molecular Markers ◽  
Muscle Development ◽  
Morphological Changes ◽  
Muscle Differentiation ◽  
Common Theme ◽  
Cellular Mechanisms ◽  
Larval Muscle ◽  
Before And After ◽  
Flight Muscles ◽  
Mutant Combination

Pattern formation in muscle development is often mediated by special cells called muscle organizers. During metamorphosis in Drosophila, a set of larval muscles function as organizers and provide scaffolding for the development of the dorsal longitudinal flight muscles. These organizers undergo defined morphological changes and dramatically split into templates as adult fibers differentiate during pupation. We have investigated the cellular mechanisms involved in the use of larval fibers as templates. Using molecular markers that label myoblasts and the larval muscles themselves, we show that splitting of the larval muscles is concomitant with invasion by imaginal myoblasts and the onset of differentiation. We show that the Erect wing protein, an early marker of muscle differentiation, is not only expressed in myoblasts just before and after fusion, but also in remnant larval nuclei during muscle differentiation. We also show that interaction between imaginal myoblasts and larval muscles is necessary for transformation of the larval fibers. In the absence of imaginal myoblasts, the earliest steps in metamorphosis, such as the escape of larval muscles from histolysis and changes in their innervation, are normal. However, subsequent events, such as the splitting of these muscles, fail to progress. Finally, we show that in a mutant combination, null for Erect wing function in the mesoderm, the splitting of the larval muscles is aborted. These studies provide a genetic and molecular handle for the understanding of mechanisms underlying the use of muscle organizers in muscle patterning. Since the use of such organizers is a common theme in myogenesis in several organisms, it is likely that many of the processes that we describe are conserved.

scholarly journals How effective is river restoration in re-establishing groundwater–surface water interactions? – A case study

2015 ◽  
Vol 19 (6) ◽  
pp. 2663-2672 ◽  
Author(s):  
A.-M. Kurth ◽  
C. Weber ◽  
M. Schirmer
Keyword(s):  
Surface Water ◽  
River Restoration ◽  
Morphological Changes ◽  
Cost Effective ◽  
Urban Stream ◽  
Distributed Temperature Sensing ◽  
River Bed ◽  
Before And After ◽  
Restoration Measures

Abstract. In this study, we investigated whether river restoration was successful in re-establishing groundwater–surface water interactions in a degraded urban stream. Restoration measures included morphological changes to the river bed, such as the installation of gravel islands and spur dykes, as well as the planting of site-specific riparian vegetation. Standard distributed temperature sensing (DTS) and novel active and passive DTS approaches were employed to study groundwater–surface water interactions in two reference streams and an experimental reach of an urban stream before and after its restoration. Radon-222 analyses were utilized to validate the losing stream conditions of the urban stream in the experimental reach. Our results indicated that river restoration at the study site was indeed successful in increasing groundwater–surface water interactions. Increased surface water downwelling occurred locally at the tip of a gravel island created during river restoration. Hence, the installation of in-stream structures increased the vertical connectivity and thus groundwater–surface water interactions. With the methods presented in this publication, it would be possible to routinely investigate the success of river restorations in re-establishing vertical connectivity, thereby gaining insight into the effectiveness of specific restoration measures. This, in turn, would enable the optimization of future river restoration projects, rendering them more cost-effective and successful.

Biochemical, molecular, and morphological variations of flight muscles before and after dispersal flight in a eusocial termite, Reticulitermes chinensis

2020 ◽  
Vol 28 (1) ◽  
pp. 77-92
Author(s):  
Zhen‐Yu Zhang ◽  
Jing Ren ◽  
Fei Chu ◽  
Jun‐Xia Guan ◽  
Guang‐Yu Yang ◽  
...  
Keyword(s):  
Morphological Variations ◽  
Before And After ◽  
Flight Muscles

scholarly journals Evolutionarily conserved regulation of embryonic fast-twitch skeletal muscle differentiation by Pbx factors

2020 ◽  
Author(s):  
Gist H. Farr ◽  
Bingsi Li ◽  
Maurizio Risolino ◽  
Nathan M. Johnson ◽  
Zizhen Yao ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Muscle Differentiation ◽  
Mouse Embryos ◽  
Fast Muscle ◽  
Fiber Types ◽  
Skeletal Muscle Differentiation ◽  
Homeodomain Proteins ◽  
Evolutionarily Conserved ◽  
Fast Twitch

SummaryVertebrate skeletal muscles are composed of both slow-twitch and fast-twitch fiber types. How the differentiation of distinct fiber types is activated during embryogenesis is not well characterized. Skeletal muscle differentiation is initiated by the activity of the myogenic basic helix-loop-helix (bHLH) transcription factors Myf5, Myod1, Myf6, and Myog. Myod1 functions as a muscle master regulatory factor and directly activates muscle differentiation genes, including those specific to both slow and fast muscle fibers. Our previous studies showed that Pbx TALE-class homeodomain proteins bind with Myod1 on the promoter of the zebrafish fast muscle gene mylpfa and are required for proper activation of mylpfa expression and the fast-twitch muscle-specific differentiation program in zebrafish embryos. Pbx proteins have also been shown to bind regulatory regions of muscle differentiation genes in mammalian muscle cells in culture. Here, we use new zebrafish mutant strains to confirm the essential roles of zebrafish Pbx factors in embryonic fast muscle differentiation. Furthermore, we examine the requirements for Pbx genes in mouse embryonic skeletal muscle differentiation, an area that has not been investigated in the mammalian embryo. Removing Pbx1 function from skeletal muscle in Myf5Cre/+;Pbx1fl/fl mouse embryos has minor effects on embryonic muscle development. However, concomitantly deleting Pbx2 function in Myf5Cre/+;Pbx1fl/fl;Pbx2-/- mouse embryos causes delayed activation and reduced expression of fast muscle differentiation genes. In the mouse, Pbx1/Pbx2-dependent fast muscle genes closely match those that have been previously shown to be dependent on murine Six1 and Six4. This work establishes evolutionarily conserved requirements for Pbx factors in embryonic fast muscle differentiation. Our studies are revealing how Pbx homeodomain proteins help direct specific cellular differentiation pathways.

scholarly journals Spectral OCT-Angiography in En Face Mode for Detection of Morphological Changes in the Retinal Pigment Epithelium before and after Selective Micro-Pulse Laser Exposure in Patients with Central Serous Chorioretinopathy

2019 ◽  
Vol 16 (2) ◽  
pp. 192-201
Author(s):  
P. L. Volodin ◽  
E. V. Ivanova ◽  
E. Iu. Polyakova ◽  
A. V. Fomin
Keyword(s):  
Retinal Pigment Epithelium ◽  
Central Serous Chorioretinopathy ◽  
Morphological Changes ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Laser System ◽  
Subretinal Fluid ◽  
Micropulse Laser ◽  
En Face ◽  
Before And After

Purpose — to study the morphological changes of the retinal pigment epithelium (RPE) by optical coherence tomography-angiography (OCT-A) in En Face mode before and after selective micropulse laser irradiation in patients with central serous chorioretinopathy (CSC), determine the correspondence between the topographic location of RPE defects and detachment on the OCT-angiogram in En Face mode and points of leakage on the FAG.Patients and methods. There were 20 patients (21 eyes) with CSC before and after laser treatment under the observation. All patients underwent high-resolution FAG and OCT-A using Angio Retina 2×2 or 3×3 mm protocol and Angio Retina HD 6×6 mm. The treatment was carried out in a selective micropulse mode with individual selection of parameters using the Navilas 577s navigation laser system (OD-OS, Germany) or the IQ 577 laser system (IRIDEX, USA).Results were evaluated at 2 weeks and 1 month after treatment. Results. In all cases, the leaking points of the subretinal fluid on FAG corresponded to the topographic location of defects and detachments of RPE detachment on OKT-A En Face. According to OCT-A En Face, the following morphological changes were revealed: in 5 cases — single defects of RPE, in 7 cases — multiple defects of RPE, in 9 cases of slit-like detachment of RPE, in 3 patients a combination of slit-like detachment and defect RPE. The sizes of RPE defects varied in the range from 21 to 159 microns, while their rounded shape prevailed. 1 month after the selective micropulse laser effect on OCT-A in the En Face mode, the defects were closed and the RPE detachments fit in all patients, which resulted in resorption of the subretinal fluid and the neurosensory retina attachment.Findings. OCT-A in En Face mode is a highly informative diagnostic method that allows noninvasive detection of morphological changes in RPE with a clear topographic localization relative to the retinal vascular network, as well as evaluating the effectiveness of selective micropulse laser treatment in patients with CSC. 

scholarly journals Morphological changes in the trabecular meshwork and Schlemm’s canal after treatment with topical intraocular pressure-lowering agents

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji-Hye Park ◽  
Hyun Woo Chung ◽  
Eun Gyu Yoon ◽  
Min Jung Ji ◽  
Chungkwon Yoo ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Morphological Changes ◽  
Open Angle Glaucoma ◽  
Anterior Segment ◽  
Schlemm’S Canal ◽  
Schlemm's Canal ◽  
Before And After ◽  
Treatment Naïve ◽  
Aqueous Outflow

AbstractGlaucoma treatment is usually initiated with topical medication that lowers the intraocular pressure (IOP) by reducing the aqueous production, enhancing the aqueous outflow, or both. However, the effect of topical IOP-lowering medications on the microstructures of the aqueous outflow pathway are relatively unknown. In this retrospective, observational study, 56 treatment-naïve patients with primary open-angle glaucoma were enrolled. Images of the nasal and temporal corneoscleral limbus were obtained using anterior segment optical coherence tomography (AS-OCT). The conjunctival vessels and iris anatomy were used as landmarks to select the same limbal area scan, and the trabecular meshwork (TM) width, TM thickness, and Schlemm’s canal (SC) area were measured before and after using the IOP-lowering agents for 3 months. Among the 56 patients enrolled, 33 patients used prostaglandin (PG) analogues, and 23 patients used dorzolamide/timolol fixed combination (DTFC). After 3 months of DTFC usage, the TM width, TM thickness, and SC area did not show significant changes in either the nasal or temporal sectors. Conversely, after prostaglandin analog usage, the TM thickness significantly increased, and the SC area significantly decreased (all P < 0.01). These findings warrant a deeper investigation into their relationship to aqueous outflow through the conventional and unconventional outflow pathways after treatment with PG analogues.

scholarly journals Indirect flight muscles in Drosophila melanogaster as a tractable model to study muscle development and disease

2020 ◽  
Vol 64 (1-2-3) ◽  
pp. 167-173
Author(s):  
Saroj Jawkar ◽  
Upendra Nongthomba
Keyword(s):  
Drosophila Melanogaster ◽  
Muscle Development ◽  
Myoblast Fusion ◽  
Successful Development ◽  
Adult Muscle ◽  
Attachment Sites ◽  
Flight Muscles ◽  
And Function

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.

scholarly journals Preaggregation reactions of platelets

Blood ◽  
1981 ◽  
Vol 58 (3) ◽  
pp. 477-490 ◽  
Author(s):  
AR Gear
Keyword(s):  
Particle Density ◽  
Morphological Changes ◽  
Adenosine Diphosphate ◽  
Temperature Cycle ◽  
Volume Changes ◽  
Platelet Volume ◽  
Particle Volume ◽  
Before And After ◽  
Subsequent Exposure ◽  
Platelet Shape

Abstract Whether platelet volume increases during the morphological changes preceding aggregation has been investigated. Previous research is controversial; resistive-counting techniques reveal an increase, centrifugal methods do not. Platelets were sized with a computerized, resistive-particle counter before and after incubation with adenosine diphosphate (ADP). Resistive volume increased by 14% (p less than 0.001) in the absence of EDTA, and only 7% in its presence (ADP, 10 micro M). EDTA inhibited platelet volume changes, whether these were shrinking induced by warming or swelling by ADP. Handling of platelets, such as during centrifugation, also caused particle swelling. Particle density decreased after ADP exposure, without release of serotonin, suggesting uptake of water. Platelet shape was experimentally manipulated to test the hypothesis that resistive volume changes stem from artifacts of particle shape. Scanning electron microscopy confirmed that colchicine, chlorpromazine, and a temperature cycle of 0 degrees to 37 degrees all caused extensive alteration from the disc shape. Subsequent exposure to ADP increased resistive volume, and in the case of chlorpromazine, no long pseudopodia were extruded. It is concluded that preaggregation reactions of platelets can be associated with an increase in particle volume, and that earlier research based on centrifugation and the presence of ETA failed to reveal the increase because of inhibitory and apparent swelling effects.

scholarly journals Spectrophotometric characterization of the Philae landing site and surroundings with the Rosetta/OSIRIS cameras

2020 ◽  
Vol 498 (1) ◽  
pp. 1221-1238
Author(s):  
Hong Van Hoang ◽  
S Fornasier ◽  
E Quirico ◽  
P H Hasselmann ◽  
M A Barucci ◽  
...  
Keyword(s):  
Total Mass ◽  
Morphological Changes ◽  
Landing Site ◽  
Spectral Slope ◽  
Water Ice ◽  
Total Mass Loss ◽  
Before And After ◽  
Comet 67P ◽  
Cometary Activity

ABSTRACT We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov–Gerasimenko on 2014 November 12. Over 1000 OSIRIS-level 3B images were analysed, which cover the 2014 August–2016 September timeframe, with spatial resolution ranging from 7.6 m pixel−1 to approximately 0.06 m pixel−1. We found that the Abydos site is as dark as the global 67P nucleus and spectrally red, with an average albedo of 6.5 per cent at 649 nm and a spectral slope value of about 17 per cent/(100 nm) at 50° phase angle. Similar to the whole nucleus, the Abydos site also shows phase reddening but with lower coefficients than other regions of the comet, which may imply a thinner cover of microscopically rough regolith compared to other areas. Seasonal variations, as already noticed for the whole nucleus, were also observed. We identified some potential morphological changes near the landing site implying a total mass-loss of (4.7–7.0) × 105 kg. Small spots ranging from 0.1 to 27 m2 were observed close to Abydos before and after perihelion. Their estimated water ice abundance reaches 30–40 per cent locally, indicating fresh exposures of volatiles. Their lifetime ranges from a few hours up to three months for two pre-perihelion spots. The Abydos surroundings showed a low level of cometary activity compared to other regions of the nucleus. Only a few jets are reported originating nearby Abydos, including a bright outburst that lasted for about 1 h.

scholarly journals Whether Keratectasia Area Shown in Corneal Topography Is Appropriate for Evaluating the Effect of Corneal Cross-Linking for Keratoconus: A 12-Month Follow-Up Study

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Jia Wang ◽  
Zhiwei Li ◽  
Huankai Zhang ◽  
Ning Gao ◽  
Guoying Mu
Keyword(s):  
Endothelial Cell ◽  
Linear Regression ◽  
Early Stage ◽  
Morphological Changes ◽  
Corneal Thickness ◽  
Corneal Topography ◽  
Cross Linking ◽  
Follow Up Study ◽  
Before And After

Purpose. To analyze the keratectasia area (KEA) shown in corneal topography before and after corneal cross-linking (CXL) in patients with progressive keratoconus (KC) and figure out whether KEA is appropriate for evaluating the effect of CXL. Methods. A retrospective analysis was conducted in 34 eyes from 24 progressive KC patients who have underwent CXL from 2015 to 2017. Area with K-value more than 47D shown in the corneal topography was marked and identified as KEA. Keratometry (K1, K2, and Kmax), KEA, thinnest corneal thickness (TCT), and endothelial cell density (ECD) were evaluated preoperatively or at months 3, 6, and 12 postoperatively. The changes of KEA before and after operation were evaluated. The relation of KEA and other parameters, including Kmax and TCT, was analyzed. Results. Linear regression model revealed the KEA, Kmax, K1, and K2 decreased after CXL in model y = 0.9622 -0.02408 x (P<0.05), y = 0.9982 -0.003469 x(P<0.05), y = 0.9977 + -0.001347 x(P<0.05), y = 0.9992 + -0.001779 x(P<0.05) (y represents KEA, Kmax, K1, or K2; x represents time (month)). The KEA is significantly decreased in early stage (before month 3) (P<0.05); however, the Kmax, K1, and K2 have no significant decrease in early stage (P= 0.09, 0.19, 0.32). Conclusions. The KEA is more sensitive than K-value in describing the morphological changes of cornea after CXL, especially in early stage after treatment.

scholarly journals Zfp422 promotes skeletal muscle differentiation by regulating EphA7 to induce appropriate myoblast apoptosis

2019 ◽  
Vol 27 (5) ◽  
pp. 1644-1659 ◽  
Author(s):  
Yaping Nie ◽  
Shufang Cai ◽  
Renqiang Yuan ◽  
Suying Ding ◽  
Xumeng Zhang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Zinc Finger ◽  
Muscle Development ◽  
Zinc Finger Protein ◽  
Critical Role ◽  
Muscle Differentiation ◽  
C2c12 Cells ◽  
Myoblast Differentiation ◽  
Skeletal Muscle Differentiation ◽  
Finger Protein

Abstract Zinc finger protein 422 (Zfp422) is a widely expressed zinc finger protein that serves as a transcriptional factor to regulate downstream gene expression, but until now, little is known about its roles in myogenesis. We found here that Zfp422 plays a critical role in skeletal muscle development and regeneration. It highly expresses in mouse skeletal muscle during embryonic development. Specific knockout of Zfp422 in skeletal muscle impaired embryonic muscle formation. Satellite cell-specific Zfp422 deletion severely inhibited muscle regeneration. Myoblast differentiation and myotube formation were suppressed in Zfp422-deleted C2C12 cells, isolated primary myoblasts, and satellite cells. Chromatin Immunoprecipitation Sequencing (ChIP-Seq) revealed that Zfp422 regulated ephrin type-A receptor 7 (EphA7) expression by binding an upstream 169-bp DNA sequence, which was proved to be an enhancer of EphA7. Knocking EphA7 down in C2C12 cells or deleting Zfp422 in myoblasts will inhibit cell apoptosis which is required for myoblast differentiation. These results indicate that Zfp422 is essential for skeletal muscle differentiation and fusion, through regulating EphA7 expression to maintain proper apoptosis.

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