scholarly journals Oriented basement membrane fibrils provide a memory for F-actin planar polarization via the Dystrophin-Dystroglycan complex during tissue elongation

2019 ◽  
Author(s):  
Fabiana Cerqueira Campos ◽  
Cynthia Dennis ◽  
Hervé Alégot ◽  
Cornelia Fritsch ◽  
Adam Isabella ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Ovarian Follicle ◽  
Follicle Cell ◽  
Autonomous Control ◽  
Stress Fibers ◽  
Follicle Growth ◽  
Growth Promoting ◽  
Fibers Orientation ◽  
Open Question ◽  
The Relationship

SummaryHow extracellular matrix participates to tissue morphogenesis is still an open question. In the Drosophila ovarian follicle, it has been proposed that after Fat2-dependent planar polarization of the follicle cell basal domain, oriented basement membrane (BM) fibrils and F-actin stress fibers constrain follicle growth, promoting its axial elongation. However, the relationship between BM fibrils and stress fibers and their respective impact on elongation are unclear. We found that Dystroglycan (Dg) and Dystrophin (Dys) are involved in BM fibril deposition. Moreover, they orient stress fibers, by acting locally and in parallel to Fat2. Nonetheless, Dg-Dys complex-mediated cell autonomous control of F-actin fibers orientation relies on the previous BM fibril deposition, indicating two distinct but interdependent functions. Thus, the Dg-Dys complex works as a critical organizer of the epithelial basal domain, regulating both F-actin and BM. Furthermore, BM fibrils act as a persistent cue for the orientation of stress fibers that are the main effector of elongation.

scholarly journals Mathematical modelling of oxygen transport-limited follicle growth

Reproduction ◽  
2007 ◽  
Vol 133 (6) ◽  
pp. 1095-1106 ◽  
Author(s):  
G P Redding ◽  
J E Bronlund ◽  
A L Hart
Keyword(s):  
Mathematical Modelling ◽  
Oxygen Transport ◽  
Size Range ◽  
Ovarian Follicle ◽  
Antral Follicle ◽  
Follicle Growth ◽  
Preantral Follicles ◽  
Formation Stage ◽  
Ultimate Fate ◽  
Further Development

Mathematical modelling was used to investigate oxygen transport in the developing ovarian follicle. In contrast to previous findings, the results show that oxygen can reach the oocyte in large preantral follicles. This is largely due to the inclusion of fluid voidage in the model and improved estimates of oxygen diffusion coefficients through the granulosa. The results also demonstrate that preantral follicles will eventually reach a size beyond which further growth will result in the follicle becoming increasingly anoxic. The predicted size range at which this occurs is consistent with the size range at which antrum formation is observed in many mammals. This suggests that the antrum formation stage of follicular growth may be pivotal to the further development and ultimate fate of the follicle, and that antrum formation itself may represent a mechanism by which the follicle can overcome oxygen limitations. This was supported through extension of the model to the antral follicle, which showed that antrum formation can provide a way in which the follicle can continue to grow and yet avoid becoming hypoxic. The results of the model were consistent with observed follicle development.

scholarly journals Involvement of hyaluronan synthesis in ovarian follicle growth in rats

Reproduction ◽  
2014 ◽  
Vol 147 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Noriyuki Takahashi ◽  
Wataru Tarumi ◽  
Bunpei Ishizuka
Keyword(s):  
Ovarian Follicle ◽  
Primary Site ◽  
Corpora Lutea ◽  
Follicular Atresia ◽  
Follicle Growth ◽  
Adult Rats ◽  
Antral Follicles ◽  
Cell Layers ◽  
Ha Synthase

Most of the previous studies on ovarian hyaluronan (HA) have focused on mature antral follicles or corpora lutea, but scarcely on small preantral follicles. Moreover, the origin of follicular HA is unknown. To clarify the localization of HA and its synthases in small growing follicles, involvement of HA in follicle growth, and gonadotropin regulation of HA synthase (Has) gene expression, in this study, perinatal, immature, and adult ovaries of Wistar-Imamichi rats were examined histologically and biochemically and byin vitrofollicle culture. HA was detected in the extracellular matrix of granulosa and theca cell layers of primary follicles and more advanced follicles. Ovarian HA accumulation ontogenetically started in the sex cords of perinatal rats, and its primary site shifted to the intrafollicular region of primary follicles within 5 days of birth. TheHas1–3mRNAs were expressed in the ovaries of perinatal, prepubertal, and adult rats, and the expression levels ofHas1andHas2genes were modulated during the estrous cycle in adult rats and following administration of exogenous gonadotropins in immature acyclic rats. TheHas1andHas2mRNAs were predominantly localized in the theca and granulosa cell layers of growing follicles respectively. Treatments with chemicals known to reduce ovarian HA synthesis induced follicular atresia. More directly, the addition ofStreptomyceshyaluronidase, which specifically degrades HA, induced the arrest of follicle growth in anin vitroculture system. These results indicate that gonadotropin-regulated HA synthesis is involved in normal follicle growth.

scholarly journals From Culture 1.0 to Culture 3.0: Three Socio-Technical Regimes of Social and Economic Value Creation through Culture, and Their Impact on European Cohesion Policies

2018 ◽  
Vol 10 (11) ◽  
pp. 3923 ◽  
Author(s):  
Pier Sacco ◽  
Guido Ferilli ◽  
Giorgio Tavano Blessi
Keyword(s):  
Cultural Production ◽  
Value Creation ◽  
Cultural Policy ◽  
Policy Design ◽  
Economic Value ◽  
Cultural Participation ◽  
Social Value Creation ◽  
Open Question ◽  
The Relationship

We develop a new conceptual framework to analyze the evolution of the relationship between cultural production and different forms of economic and social value creation in terms of three alternative socio-technical regimes that have emerged over time. We show how, with the emergence of the Culture 3.0 regime characterized by novel forms of active cultural participation, where the distinction between producers and users of cultural and creative contents is increasingly blurred, new channels of social and economic value creation through cultural participation acquire increasing importance. We characterize them through an eight-tier classification, and argue on this basis why cultural policy is going to acquire a central role in the policy design approaches of the future. Whether Europe will play the role of a strategic leader in this scenario in the context of future cohesion policies is an open question.

Inhibition of Ovarian Follicle Growth by a Chemical Antiestrogen

1982 ◽  
Vol 16 (4) ◽  
pp. 230-236 ◽  
Author(s):  
R. Nakano ◽  
T. Nakayama ◽  
M. Iwao
Keyword(s):  
Ovarian Follicle ◽  
Follicle Growth

X-Ray Binary Stars and Ovarian Follicle Growth: Math Models in Astrophysics and Physiology

2010 ◽  
Author(s):  
Gordon E. Sarty ◽  
Curtis Saxton ◽  
Kinwah Wu ◽  
Roger Pierson ◽  
N. Mebarki ◽  
...  
Keyword(s):  
Binary Stars ◽  
Ovarian Follicle ◽  
Follicle Growth ◽  
X Ray

scholarly journals Being Disoriented: Uncertain Encounters with Disability

2016 ◽  
Vol 36 (2) ◽  
Author(s):  
Ryan C. Parrey
Keyword(s):  
Disability Studies ◽  
Meeting Point ◽  
Open Question ◽  
The Relationship

<p>Disorienting encounter with disability are those in which the meaning of disability is an open question, and in which our relation to it is questionable. This essay explores the relationship between disability and disorientation on conceptual but also concrete levels. First, I examine the connection between disability and disorientation within disability studies. Second, I provide a preliminary sketch of disorientation through what I call <em>ontic disruption</em> and <em>ontological disorientation</em>. Third, I take up Leder's (1990) articulation of bodily disappearance and embodied dysappearance to address ableist violence. Finally, I develop the notion of <em>dysorientation — </em>a prolonged, persistent or recurrent sense of disorientation — as a useful concept for understanding experiences of ableism but also as a significant meeting point between impairment and disability. </p><p> </p>

scholarly journals Mechanics defines the spatial pattern of compensatory proliferation

2021 ◽  
Author(s):  
Takumi Kawaue ◽  
Ivan Yow ◽  
Anh Phuong Le ◽  
Yuting Lou ◽  
Mavis Loberas ◽  
...  
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Cell Loss ◽  
Spatial Inhomogeneity ◽  
Cellular Functions ◽  
Cell Numbers ◽  
Compensatory Proliferation ◽  
A Cell ◽  
Growth Promoting ◽  
Open Question

The number of cells in tissues is tightly controlled by cell division and cell death, and misregulation of cell numbers could lead to pathological conditions such as cancer. To maintain cell numbers in a tissue, a cell elimination process named programmed cell death or apoptosis, stimulates the proliferation of neighboring cells. This mechanism is called apoptosis-induced compensatory proliferation, which was originally reported more than 40 years ago. While only a limited number of the neigboring cells need to divide to compensate for apoptotic cell loss, the mechanisms that select cells for undergoing division remain an open question. Here we found that the spatial inhomogeneity in mechanotransduction through a growth-promoting transcription co-activator Yes-associated protein (YAP) in the neighboring tissue, accounts for the inhomogeneity of compensatory proliferation. Such inhomogeneous mechanotransduction arises from the combination of the non-uniform distribution of nuclear size, which is inherent in tissues, and the non-uniform pattern of mechanical force applied to the neighboring cells upon apoptosis. Our findings from a mechanical perspective complement the current biochemical understanding of compensatory growth and provide additional insights into cellular functions of how tissue precisely maintains its homeostasis.

Studies on the Ovarian Follicle Cells of Drosophila

1963 ◽  
Vol s3-104 (67) ◽  
pp. 297-320
Author(s):  
R. C. KING ◽  
ELIZABETH A. KOCH
Keyword(s):  
Ovarian Follicle ◽  
Protein A ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Membrane Material ◽  
Adjacent Layer ◽  
Membrane Formation ◽  
Precursor Material ◽  
Egg Shell

Studies are described of the ultrastructure of the follicle cells which invest the oocyte of Drosophila melanogaster at the time of vitelline membrane formation. Of particular interest are organelles made up of endoplasmic reticulum organized into a husk of concentric lamellae which surround lipidal droplets. These epithelial bodies are seen only at the time the vitelline membrane is being formed, and it is assumed therefore that the lipidal material of the epithelial body may be utilized somehow in the fabrication of the vitelline membrane. Cytochemical studies have shown this membrane to contain at least 5 classes of compounds; a protein, two lipids (which may be distinguished by differences in their resistance to extraction by various solvents), and 2 polysaccharides (1 neutral and 1 acidic). Studies were made of vitelline membrane formation in the ovaries of flies homozygous for either of 2 recessive, female-sterile genes (tiny and female sterile). In the case of the ty mutation vitelline membrane material is sometimes secreted between follicle and nurse cells, while in the mutant fes vitelline membrane is observed in rare instances to be secreted between follicle cells and an adjacent layer of tumour cells. In the latter case the vitelline membrane shows altered cytochemical properties. The fact that vitelline membrane can be secreted by follicle cells not adjacent to an oocyte demonstrates that it is the follicle cell rather than the oocyte that plays the major role in the secretion of the precursor material of the vitelline membrane. Subsequently the follicle cells secrete the egg-shell, or chorion, which is subdivided into a dense, compartmented, inner endochorion, and a pale, outer exochorion. A description is given of the ultrastructure of the follicle cells during the secretion of the endochorion and the exochorion. The endochorion contains a protein, a polysaccharide, and a lipid, all of which may be distinguished cytochemically from the vitelline membrane compounds. The exochorion contains large amounts of acidic mucopolysaccharides. Specialized follicle cells form the micropylar apparatus and the chorionic appendages. The formation of the chorion and chorionic appendages is discussed in the light of information gained from abnormalities of the chorions and chorionic appendages seen in ty and fs 2.1 oocytes. Subsequent to the time the egg leaves the ovariole a layer of waterproofing wax is secreted between the vitelline membrane and the chorion.

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