scholarly journals The Genes raw and ribbon Are Required for Proper Shape of Tubular Epithelial Tissues in Drosophila

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 243-253 ◽  
Author(s):  
Joseph Jack ◽  
Guy Myette
Keyword(s):  
Embryonic Development ◽  
Salivary Glands ◽  
Cell Shape ◽  
Malpighian Tubules ◽  
Dorsal Closure ◽  
Epithelial Tissues ◽  
Cell Rearrangement

Abstract The products of two genes, raw and ribbon (rib), are required for the proper morphogenesis of a variety of tissues. Malpighian tubules mutant for raw or rib are wider and shorter than normal tubules, which are only two cells in circumference when they are fully formed. The mutations alter the shape of the tubules beginning early in their formation and block cell rearrangement late in development, which normally lengthens and narrows the tubes. Mutations of both genes affect a number of other tissues as well. Both genes are required for dorsal closure and retraction of the CNS during embryonic development. In addition, rib mutations block head involution, and broaden and shorten other tubular epithelia (salivary glands, tracheae, and hindgut) in much same manner as they alter the shape of the Malpighian tubules. In tissues in which the shape of cells can be observed readily, rib mutations alter cell shape, which probably causes the change in shape of the organs that are affected. In double mutants raw enhances the phenotypes of all the tissues that are affected by rib but unaffected by raw alone, indicating that raw is also active in these tissues.

scholarly journals Inhibition of Aurora Kinase B activity disrupts development and differentiation of salivary glands

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Abeer K. Shaalan ◽  
Tathyane H. N. Teshima ◽  
Abigail S. Tucker ◽  
Gordon B. Proctor
Keyword(s):  
Cell Cycle ◽  
Embryonic Development ◽  
Salivary Glands ◽  
Aurora Kinase ◽  
Serine Threonine Kinase ◽  
Aurora Kinase B ◽  
Development And Differentiation ◽  
Differentiation Marker ◽  
Key Events

AbstractLittle is known about the key molecules that regulate cell division during organogenesis. Here we determine the role of the cell cycle promoter aurora kinase B (AURKB) during development, using embryonic salivary glands (E-SGs) as a model. AURKB is a serine/threonine kinase that regulates key events in mitosis, which makes it an attractive target for tailored anticancer therapy. Many reports have elaborated on the role of AURKB in neoplasia and cancer; however, no previous study has shown its role during organ development. Our previous experiments have highlighted the essential requirement for AURKB during adult exocrine regeneration. To investigate if AURKB is similarly required for progression during embryonic development, we pharmacologically inhibited AURKB in developing submandibular glands (SMGs) at embryonic day (E)13.5 and E16.5, using the highly potent and selective drug Barasertib. Inhibition of AURKB interfered with the expansion of the embryonic buds. Interestingly, this effect on SMG development was also seen when the mature explants (E16.5) were incubated for 24 h with another cell cycle inhibitor Aphidicolin. Barasertib prompted apoptosis, DNA damage and senescence, the markers of which (cleaved caspase 3, γH2AX, SA-βgal and p21, respectively), were predominantly seen in the developing buds. In addition to a reduction in cell cycling and proliferation of the epithelial cells in response to AURKB inhibition, Barasertib treatment led to an excessive generation of reactive oxygen species (ROS) that resulted in downregulation of the acinar differentiation marker Mist1. Importantly, inhibition of ROS was able to rescue this loss of identity, with Mist1 expression maintained despite loss of AURKB. Together, these data identify AURKB as a key molecule in supporting embryonic development and differentiation, while inhibiting senescence-inducing signals during organogenesis.

scholarly journals Progression of Watermelon Bud Necrosis Virus Infection in Its Vector, Thrips palmi

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 392
Author(s):  
Amalendu Ghosh ◽  
Priti ◽  
Bikash Mandal ◽  
Ralf G. Dietzgen
Keyword(s):  
Virus Infection ◽  
Salivary Glands ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Malpighian Tubules ◽  
Necrosis Virus ◽  
Posterior Portion ◽  
Thrips Palmi ◽  
Thrips Species ◽  
Anterior Midgut

Thrips are important pests of agricultural, horticultural, and forest crops worldwide. In addition to direct damages caused by feeding, several thrips species can transmit diverse tospoviruses. The present understanding of thrips–tospovirus relationships is largely based on studies of tomato spotted wilt virus (TSWV) and Western flower thrips (Frankliniella occidentalis). Little is known about other predominant tospoviruses and their thrips vectors. In this study, we report the progression of watermelon bud necrosis virus (WBNV) infection in its vector, melon thrips (Thrips palmi). Virus infection was visualized in different life stages of thrips using WBNV-nucleocapsid protein antibodies detected with FITC-conjugated secondary antibodies. The anterior midgut was the first to be infected with WBNV in the first instar larvae. The midgut of T. palmi was connected to the principal salivary glands (PSG) via ligaments and the tubular salivary glands (TSG). The infection progressed to the PSG primarily through the connecting ligaments during early larval instars. The TSG may also have an ancillary role in disseminating WBNV from the midgut to PSG in older instars of T. palmi. Infection of WBNV was also spread to the Malpighian tubules, hindgut, and posterior portion of the foregut during the adult stage. Maximum virus-specific fluorescence in the anterior midgut and PSG indicated the primary sites for WBNV replication. These findings will help to better understand the thrips–tospovirus molecular relationships and identify novel potential targets for their management. To our knowledge, this is the first report of the WBNV dissemination path in its vector, T. palmi.

Memoirs: The Embryonic Development of the Stick-Insect, Carausius morosus

1936 ◽  
Vol s2-78 (311) ◽  
pp. 487-511
Author(s):  
A. J. THOMAS
Keyword(s):  
Embryonic Development ◽  
Stick Insect ◽  
Malpighian Tubules ◽  
Germ Band ◽  
Ventral Plate ◽  
Carausius Morosus ◽  
Gut Epithelium ◽  
Cleavage Nucleus ◽  
Endodermal Cells ◽  
Late Stages

1. The maturation of the egg takes place in the ovarian tube, and is immediately followed by the formation of the cleavagenucleus and its division into many nuclei. 2. The entire products of the cleavage-nucleus migrate to the surface to form the blastoderm. Cleavage of the yolk was not observed even in late stages. Yolk-cells are absent when the blastoderm is being formed. 3. Primitive endodermal cells are proliferated from the middle of the germ-band, and form a membrane between the germ-band and the yolk. The membrane is present only in embryonic stages; some of the cells proliferated wander into the yolk and act as vitellophags. 4. Mesoderm is formed by proliferation of cells from the ventral plate. It is preceded by the formation of a shallow gastrular furrow, and from the bottom of this furrow proliferation takes place. The mesoderm becomes arranged in segmental masses. 5. Two masses of cells proliferated at the anterior and posterior ends of the germ-band are shown to be the endodermal rudiments from which the mid-gut epithelium is formed. The invaginations of the stomodaeum and proctodaeum grow against these masses and carry parts of the proliferating areas near their blind ends. It is shown that the various methods of mid-gut formation which have been described could be reconciled with the process described in Carausius. 6. The hinder end of the mid-gut is flanked by two plates of ectoderm which are forward extensions of the proctodaeum. Into these extensions the Malpighian tubules open, and, as their histology is identical with that of these extensions and widely different from that of the mid-gut, these tubules must be ectodermal in nature. 7. The formation of the amnion and serosa are described.

scholarly journals A Drosophila homolog of the Rac- and Cdc42-activated serine/threonine kinase PAK is a potential focal adhesion and focal complex protein that colocalizes with dynamic actin structures.

1996 ◽  
Vol 16 (5) ◽  
pp. 1896-1908 ◽  
Author(s):  
N Harden ◽  
J Lee ◽  
H Y Loh ◽  
Y M Ong ◽  
I Tan ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Cell Shape ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Epidermal Cells ◽  
Dorsal Closure ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Amino Terminal ◽  
Drosophila Homolog

Changes in cell morphology are essential in the development of a multicellular organism. The regulation of the cytoskeleton by the Rho subfamily of small GTP-binding proteins is an important determinant of cell shape. The Rho subfamily has been shown to participate in a variety of morphogenetic processes during Drosophila melanogaster development. We describe here a Drosophila homolog, DPAK, of the serine/threonine kinase PAK, a protein which is a target of the Rho subfamily proteins Rac and Cdc42. Rac, Cdc42, and PAK have previously been implicated in signaling by c-Jun amino-terminal kinases. DPAK bound to activated (GTP-bound) Drosophila Rac (DRacA) and Drosophila Cdc42. Similarities in the distributions of DPAK, integrin, and phosphotyrosine suggested an association of DPAK with focal adhesions and Cdc42- and Rac-induced focal adhesion-like focal complexes. DPAK was elevated in the leading edge of epidermal cells, whose morphological changes drive dorsal closure of the embryo. We have previously shown that the accumulation of cytoskeletal elements initiating cell shape changes in these cells could be inhibited by expression of a dominant-negative DRacA transgene. We show that leading-edge epidermal cells flanking segment borders, which express particularly large amounts of DPAK, undergo transient losses of cytoskeletal structures during dorsal closure. We propose that DPAK may be regulating the cytoskeleton through its association with focal adhesions and focal complexes and may be participating with DRacA in a c-Jun amino-terminal kinase signaling pathway recently demonstrated to be required for dorsal closure.

Disruption of embryonic development by juvenile hormone and its mimics in Dysdercus fasciatus Sign. (Hemiptera, Pyrrhocoridae)

1974 ◽  
Vol 64 (3) ◽  
pp. 421-433 ◽  
Author(s):  
C. Wall
Keyword(s):  
Embryonic Development ◽  
Juvenile Hormone ◽  
Developmental Rate ◽  
Morphological Characters ◽  
Dorsal Closure ◽  
Dramatic Reduction ◽  
Egg Hatch ◽  
Stage Viii

AbstractThe embryonic development of Dysdercus fasciatus Sign. is described in terms of 15 arbitrary stages based on external morphological characters. The effects of treating eggs early in development with juvenile hormone and a mimic (JH) are then described in terms of the stages at which embryonic development is arrested and the resulting morphological aberrations are summarised. The effects of the treatment of two strains of D. fasciatus with two JH (Law's mimic and Ayerst synthetic juvenile hormone) are described and compared in terms of both the hatchability of the eggs and the stage distributions of the arrested embryos. Law's mimic was more effective than Ayerst SJH in preventing egg hatch, and the Malawi strain was less susceptible than the Reading strain. Embryonic development was never arrested earlier than the commencement of blastokinesis (Stage VIII). After treatment with Ayerst SJH most embryos of both strains were arrested during dorsal closure (Stages XI-XII) or at the time of eclosion (Stages XHI-XIV). Treatment of the Reading strain with Law's mimic resulted in the majority of embryos being arrested during blastokinesis (Stages VIII-X) at all doses. Examination of the timetable of development in both control and treated eggs reveals a dramatic reduction in developmental rate in treated eggs at the commencement of blastokinesis. It is suggested that JH may act on eggs of D. fasciatus in three ways: interference with eclosion, differentiation and the embryonic movements during blastokinesis.

scholarly journals Multiple Forces Contribute to Cell Sheet Morphogenesis for Dorsal Closure in Drosophila

2000 ◽  
Vol 149 (2) ◽  
pp. 471-490 ◽  
Author(s):  
Daniel P. Kiehart ◽  
Catherine G. Galbraith ◽  
Kevin A. Edwards ◽  
Wayne L. Rickoll ◽  
Ruth A. Montague
Keyword(s):  
Wound Healing ◽  
Cell Shape ◽  
Cell Sheet ◽  
Leading Edge ◽  
Drosophila Embryo ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Dorsal Closure ◽  
Purse String ◽  
Ultraviolet Laser

The molecular and cellular bases of cell shape change and movement during morphogenesis and wound healing are of intense interest and are only beginning to be understood. Here, we investigate the forces responsible for morphogenesis during dorsal closure with three approaches. First, we use real-time and time-lapsed laser confocal microscopy to follow actin dynamics and document cell shape changes and tissue movements in living, unperturbed embryos. We label cells with a ubiquitously expressed transgene that encodes GFP fused to an autonomously folding actin binding fragment from fly moesin. Second, we use a biomechanical approach to examine the distribution of stiffness/tension during dorsal closure by following the response of the various tissues to cutting by an ultraviolet laser. We tested our previous model (Young, P.E., A.M. Richman, A.S. Ketchum, and D.P. Kiehart. 1993. Genes Dev. 7:29–41) that the leading edge of the lateral epidermis is a contractile purse-string that provides force for dorsal closure. We show that this structure is under tension and behaves as a supracellular purse-string, however, we provide evidence that it alone cannot account for the forces responsible for dorsal closure. In addition, we show that there is isotropic stiffness/tension in the amnioserosa and anisotropic stiffness/tension in the lateral epidermis. Tension in the amnioserosa may contribute force for dorsal closure, but tension in the lateral epidermis opposes it. Third, we examine the role of various tissues in dorsal closure by repeated ablation of cells in the amnioserosa and the leading edge of the lateral epidermis. Our data provide strong evidence that both tissues appear to contribute to normal dorsal closure in living embryos, but surprisingly, neither is absolutely required for dorsal closure. Finally, we establish that the Drosophila epidermis rapidly and reproducibly heals from both mechanical and ultraviolet laser wounds, even those delivered repeatedly. During healing, actin is rapidly recruited to the margins of the wound and a newly formed, supracellular purse-string contracts during wound healing. This result establishes the Drosophila embryo as an excellent system for the investigation of wound healing. Moreover, our observations demonstrate that wound healing in this insect epidermal system parallel wound healing in vertebrate tissues in situ and vertebrate cells in culture (for review see Kiehart, D.P. 1999. Curr. Biol. 9:R602–R605).

scholarly journals Nitric oxide loading of the salivary nitric-oxide-carrying hemoproteins (nitrophorins) in the blood-sucking bug Rhodnius prolixus.

1995 ◽  
Vol 198 (5) ◽  
pp. 1093-1098
Author(s):  
R H Nussenzveig ◽  
D L Bentley ◽  
J M Ribeiro
Keyword(s):  
Nitric Oxide ◽  
Epithelial Cells ◽  
Salivary Glands ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Nadph Diaphorase ◽  
No Production ◽  
Synthetase Activity ◽  
Diaphorase Activity ◽  
Blood Sucking

The salivary glands of the blood-sucking bug Rhodnius prolixus are formed by a single layer of binucleated epithelial cells surrounded by a double layer of transversely oriented smooth muscle cells. The epithelial cells are rich in rough endoplasmic reticulum and mitochondria and have abundant microvillar projections towards the gland lumen. This cell layer surrounds a relatively large cavity where abundant secretory material is stored. Epithelial cells produce an intense and generalized NADPH diaphorase reaction, in contrast to other tissues such as brain, Malpighian tubules and skeletal muscle. Ultrastructural analysis of the osmiophilic reaction product indicates that it is localized within cytoplasmic vacuoles, a similar location to that of NADPH diaphorase (NO synthetase) activity in neuronal cells of vertebrates. Measurements of the time course of protein accumulation, NADPH diaphorase activity and the degree of nitrosylation of hemoproteins (nitrophorins) in the salivary glands of Rhodnius prolixus nymphs after a blood meal indicate that the nitrophorins are synthesized and accumulate when NO production is low (with a 25% loading of the nitrophorins during the fourth- to fifth-instar molt). NO loading of the nitrophorins increases to 90% after the molt, concomitant with a large increase in the salivary NADPH diaphorase activity. It is concluded that synthesis of NO occurs within the epithelial cells while the nitrophorins are stored extracellularly. It is hypothesized that the luminally oriented microvilli may serve as a diffusion bridge to direct intracellularly produced NO into the luminal cavity, where the nitrophorins are stored.

Characterization of the Rickettsia-like and Coxiella-like symbionts in the tick Dermacentor everestianus Hirst, 1926 (Acari: Ixodidae) from the Qinghai-Tibet Plateau

2019 ◽  
Vol 24 (1) ◽  
pp. 106
Author(s):  
Ningxin Li ◽  
Sisi Li ◽  
Duo Wang ◽  
Peng Yan ◽  
Wenying Wang ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Malpighian Tubules ◽  
Tibet Plateau ◽  
The Tibetan Plateau ◽  
Anaplasma Ovis ◽  
Dermacentor Everestianus ◽  
Qinghai Tibet Plateau ◽  
Great Damage

The tick Dermacentor everestianus is widely distributed on the Tibetan Plateau of China, where adult ticks usually parasitize sheep, yaks and horses. D. everestianus is able to transmit many zoonotic pathogens, including Francisella tularensis, Anaplasma ovis and Rickettsia raoultii-like bacteria, and can cause great damage to animals and human health. However, the symbionts in D. everestianus have not yet been investigated, which has hindered our understanding of the relationships between this tick species and associated tick-borne pathogens. In the current study, the Rickettsia-like and Coxiella-like symbionts in D. everestianus were identified and characterized. The results indicated that both Rickettsia-like (RLS-Des) and Coxiella-like (CLS-Des) symbionts showed 100% infection rates and displayed vertical transmission in D. everestianus. The RLS-Des showed a relatively higher abundance than the CLS-Des in D. everestianus. No tissue specificity was found for the RLS-Des or CLS-Des. These symbionts can inhabit the ovaries, salivary glands, midguts, Malpighian tubules and testes of D. everestianus. During the development of D. everestianus, the density of the RLS-Des showed more obvious changes than did that of the CLS-Des. Dramatic changes in the density of the RLS-Des were detected in the midguts, ovaries, salivary glands and Malpighian tubules when female D. everestianus were engorged and detached from the host, which suggested the potential role of these symbionts in the reproduction and development of D. everestianus. The dynamic changes in the density of the CLS-Des during feeding and reproduction of D. everestianus suggest the involvement of the CLS-Des in the reproduction of D. everestianus. 

Fork head prevents apoptosis and promotes cell shape change during formation of the Drosophila salivary glands

Development ◽  
2000 ◽  
Vol 127 (19) ◽  
pp. 4217-4226 ◽  
Author(s):  
M.M. Myat ◽  
D.J. Andrew
Keyword(s):  
Cell Death ◽  
Salivary Glands ◽  
Cell Shape ◽  
Secretory Cell ◽  
Apoptotic Cell ◽  
Shape Change ◽  
Nuclear Migration ◽  
Secretory Cells ◽  
Apical Surface ◽  
Fork Head

The secretory tubes of the Drosophila salivary glands are formed by the regulated, sequential internalization of the primordia. Secretory cell invagination occurs by a change in cell shape that includes basal nuclear migration and apical membrane constriction. In embryos mutant for fork head (fkh), which encodes a transcription factor homologous to mammalian hepatocyte nuclear factor 3beta (HNF-3beta), the secretory primordia are not internalized and secretory tubes do not form. Here, we show that secretory cells of fkh mutant embryos undergo extensive apoptotic cell death following the elevated expression of the apoptotic activator genes, reaper and head involution defective. We rescue the secretory cell death in the fkh mutants and show that the rescued cells still do not invaginate. The rescued fkh secretory cells undergo basal nuclear migration in the same spatial and temporal pattern as in wild-type secretory cells, but do not constrict their apical surface membranes. Our findings suggest at least two roles for fkh in formation of the embryonic salivary glands: an early role in promoting survival of the secretory cells, and a later role in secretory cell invagination, specifically in the constriction of the apical surface membrane.

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