scholarly journals Volvox as a Model for Studying Cell Death and Senescence

2021 ◽  
Vol 52 (4) ◽  
pp. 259-267
Author(s):  
A. G. Desnitskiy
Keyword(s):  
Developmental Biology ◽  
Cell Death ◽  
Green Alga ◽  
Critical Analysis ◽  
Somatic Cells ◽  
Terminal Differentiation ◽  
Next Generation ◽  
Volvox Carteri ◽  
Comparative Aspect ◽  
Ontogenetic Diversity

Abstract The spherical green alga Volvox consists of several hundred or thousand of somatic cells that undergo terminal differentiation, senescence and death, and a small number of gonidia (asexual reproductive cells) that give rise to the next generation. In the first part of this paper, the ontogenetic diversity of the genus Volvox is briefly considered, as well as the mechanisms of differentiation into the two types of cells mentioned above, which have been thoroughly studied during recent years in Volvox carteri. Then, a detailed critical analysis of the literature and some of my own data on senescence and cell death (mainly in V. carteri and, to a lesser extent, in V. aureus) was carried out, and it was noted that this aspect of Volvox developmental biology has not been sufficiently studied. Some perspectives of further research of the processes of cell death and senescence in representatives of the genus Volvox in a comparative aspect are indicated.

Differentiation in Volvox carteri: Study of Pattern Variation of Reproductive Cells

1982 ◽  
Vol 37 (10) ◽  
pp. 1023-1030 ◽  
Author(s):  
Rainer Gilles ◽  
Lothar Jaenicke
Keyword(s):  
Stem Cells ◽  
Pattern Formation ◽  
Green Alga ◽  
Somatic Cells ◽  
Basic Pattern ◽  
Volvox Carteri ◽  
Symmetrical Pattern ◽  
Intrinsic Mechanism ◽  
F Cells

Abstract Asexual spheroids of the multicellular green alga Volvox are composed of two types o f cells: non-flagellated reproductive gonidia and Chlamydomonas-like flagellated somatic cells. They are committed by a differentiating cleavage during embryogenesis. The gonidia of the adult spheroids form a symmetrical pattern consisting of four layers of four gonidia each; their position is established already in the embryos by the gonidial initials. Whereas, generally, the 16-gonidia pattern is assumed to be the basic one, most o f the spheroids have fewer gonidia (down to 8). The nine possible gonidial patterns (8 to 16 gonidia) are described and correlated to the gonidial stem cells which have been differentiated. Defects in gonidial pattern are of particular interest, since any model of differentiation has to explain not only the basic pattern formed, but also its systematic variations. Our study shows that the pattern reduction is by no means random, but governed by an intrinsic mechanism which shifts the first unequal cleavage from the 32-celled stage to the 16-celled stage. All the patterns formed can be deduced from cleavage pathways involving non-synchronous differentiation of the stem cells. Thus, pattern formation can be correlated to timing and spacing signals regulating events during embryogenesis.

Paracrystalline Aggregates of Psoriatic Keratin and Their Relation to Normal Keratin Structure

1985 ◽  
Vol 43 ◽  
pp. 680-681
Author(s):  
S. Trachtenberg ◽  
P.M. Steinert ◽  
B.L. Trus ◽  
A.C. Steven
Keyword(s):  
Cell Death ◽  
Stratum Corneum ◽  
Intermediate Filament ◽  
Skin Disease ◽  
Amorphous Matrix ◽  
Terminal Differentiation ◽  
Proteolytic Degradation ◽  
Horny Layer ◽  
Chronic Skin ◽  
Chronic Skin Disease

During terminal differentiation of vertebrate epidermis, certain specific keratin intermediate filament (KIF) proteins are produced. Keratinization of the epidermis involves cell death and disruption of the cytoplasm, leaving a network of KIF embedded in an amorphous matrix which forms the outer horny layer known as the stratum corneum. Eventually these cells are shed (desquamation). Normally, the processes of differentiation, keratinization, and desquamation are regulated in an orderly manner. In psoriasis, a chronic skin disease, a hyperkeratotic stratum corneum is produced, resulting in abnormal desquamation of unusually large scales. In this disease, the normal KIF proteins are diminished in amount or absent, and other proteins more typical of proliferative epidermal cells are present. There is also evidence of proteolytic degradation of the KIF.

scholarly journals Mitophagy: mechanisms, pathophysiological roles, and analysis

2012 ◽  
Vol 393 (7) ◽  
pp. 547-564 ◽  
Author(s):  
Wen-Xing Ding ◽  
Xiao-Ming Yin
Keyword(s):  
Cell Death ◽  
Blood Cells ◽  
Energy Homeostasis ◽  
Recent Progress ◽  
Tissue Injury ◽  
Current Knowledge ◽  
Terminal Differentiation ◽  
Cellular Functions ◽  
Drug Induced ◽  
Cellular Energy

Abstract Mitochondria are essential organelles that regulate cellular energy homeostasis and cell death. The removal of damaged mitochondria through autophagy, a process called mitophagy, is thus critical for maintaining proper cellular functions. Indeed, mitophagy has been recently proposed to play critical roles in terminal differentiation of red blood cells, paternal mitochondrial degradation, neurodegenerative diseases, and ischemia or drug-induced tissue injury. Removal of damaged mitochondria through autophagy requires two steps: induction of general autophagy and priming of damaged mitochondria for selective autophagic recognition. Recent progress in mitophagy studies reveals that mitochondrial priming is mediated either by the Pink1-Parkin signaling pathway or the mitophagic receptors Nix and Bnip3. In this review, we summarize our current knowledge on the mechanisms of mitophagy. We also discuss the pathophysiological roles of mitophagy and current assays used to monitor mitophagy.

scholarly journals Germ cell connectivity enhances cell death in response to DNA damage in the Drosophila testis

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Kevin L Lu ◽  
Yukiko M Yamashita
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Germ Cell ◽  
Germ Cells ◽  
High Sensitivity ◽  
Next Generation ◽  
Drosophila Testis

Two broadly known characteristics of germ cells in many organisms are their development as a ‘cyst’ of interconnected cells and their high sensitivity to DNA damage. Here we provide evidence that in the Drosophila testis, connectivity serves as a mechanism that confers to spermatogonia a high sensitivity to DNA damage. We show that all spermatogonia within a cyst die synchronously even when only a subset of them exhibit detectable DNA damage. Mutants of the fusome, an organelle that is known to facilitate intracyst communication, compromise synchronous spermatogonial death and reduces overall germ cell death. Our data indicate that a death-promoting signal is shared within the cyst, leading to death of the entire cyst. Taken together, we propose that intercellular connectivity supported by the fusome uniquely increases the sensitivity of the germline to DNA damage, thereby protecting the integrity of gamete genomes that are passed on to the next generation.

Collaborative Technology

2011 ◽  
pp. 157-169
Author(s):  
Levent Yilmaz
Keyword(s):  
Distance Learning ◽  
Critical Analysis ◽  
Next Generation ◽  
Basic Principles ◽  
Collaborative Technology ◽  
Team Cooperation ◽  
Deep Integration ◽  
Task Accomplishment ◽  
E Mail ◽  
And Task

This chapter presents a set of requirements for next generation groupware systems to improve team cooperation and awareness in distance learning settings. The premise of the chapter is based on the observation that in distance learning online asynchronous (e.g., e-mail, conference tools) or synchronous (e.g., chat) mechanisms are used to facilitate collaboration and coordination to complete necessary tasks. However, students are neither trained in basic principles regarding how effective cooperation takes place, nor means for their realization. Basic methods of cooperation are delineated along with a set of requirements based on a critical analysis of the elements of cooperation and team awareness. The means for realizing these elements are also discussed to present strategies to develop the proposed elements. Two scenarios are examined to demonstrate the utility of collaboration to provide deep integration of communication and task accomplishment within a unified coherent framework.

scholarly journals Chloroform fraction of Chaetomorpha brachygona, a marine green alga from Indian Sundarbans inducing autophagy in cervical cancer cells in vitro

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Indira Majumder ◽  
Subhabrata Paul ◽  
Anish Nag ◽  
Rita Kundu
Keyword(s):  
Cervical Cancer ◽  
Cell Death ◽  
Cancer Cells ◽  
Green Alga ◽  
Chloroform Fraction ◽  
Anticancer Activities ◽  
Siha Cell Line ◽  
Cervical Cancer Cells ◽  
Marine Green Alga

AbstractSundarbans Mangrove Ecosystem (SME) is a rich repository of bioactive natural compounds, with immense nutraceutical and therapeutic potential. Till date, the algal population of SME was not explored fully for their anticancer activities. Our aim is to explore the potential of these algal phytochemicals against the proliferation of cervical cancer cells (in vitro) and identify the mode of cell death induced in them. In the present work, the chloroform fraction of marine green alga, Chaetomorpha brachygona was used on SiHa cell line. The algal phytochemicals were identified by GCMS, LCMS and column chromatography and some of the identified compounds, known for significant anticancer activities, have shown strong Bcl-2 binding capacity, as analyzed through molecular docking study. The extract showed cytostatic and cytotoxic activity on SiHa cells. Absence of fragmented DNA, and presence of increased number of acidic vacuoles in the treated cells indicate nonapoptotic cell death. The mode of cell death was likely to be autophagic, as indicated by the enhanced expression of Beclin 1 and LC3BII (considered as autophagic markers) observed by Western blotting. The study indicates that, C. brachygona can successfully inhibit the proliferation of cervical cancer cells in vitro.

The Developmental Biology of Brachiopods

2001 ◽  
Vol 7 ◽  
pp. 69-88
Author(s):  
Gary Freeman
Keyword(s):  
Developmental Biology ◽  
Life History ◽  
Fossil Record ◽  
Lower Cambrian ◽  
Comprehensive Treatment ◽  
Next Generation ◽  
Lower Paleozoic ◽  
Short Course ◽  
Invertebrate Paleontology ◽  
Lower Ordovician

The chapter on anatomy in the Treatise on Invertebrate Paleontology (Part H, Brachiopoda, revised) (Williams et al., 1997) is the most current and comprehensive treatment that we have of reproduction and development in these animals. My contribution to this short course is a commentary on and addendum to this review. The study of the developmental biology of extant brachiopods describes a large part of their life history and defines several of the parameters that have to be taken into account when thinking about how a given set of genes will make it to the next generation (Havenhand, 1995). Some extant brachiopod genera like Discinisca and Crania (Neocrania) belong to families that first appeared in the fossil record during the Lower Ordovician or, as in the case of Glottidia, to a superfamily that first appeared during the Lower Cambrian. Studies on the development of these extant animals provide a picture of what the development of their Lower Paleozoic ancestors might have been like.

Effects of Huangqi (Hex) on Inducing Cell Differentiation and Cell Death in K562 and HEL Cells¤

2004 ◽  
Vol 36 (3) ◽  
pp. 211-217 ◽  
Author(s):  
Xiao-Dong Cheng ◽  
Chun-Hui Hou ◽  
Xue-Jun Zhang ◽  
Heng-Yue Xie ◽  
Wei-Ying Zhou ◽  
...  
Keyword(s):  
Cell Death ◽  
Chinese Medicine ◽  
Side Effects ◽  
Traditional Chinese Medicine ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Globin Gene ◽  
Terminal Differentiation ◽  
Point Of View ◽  
Hel Cells

Abstract Huangqi (Astragalus membranaceus), a traditional Chinese medicine, has been used to ameliorate side effects of cancer chemotherapy in China. However, little is known about its molecular mechanisms. Here we show that induction of K562 or HEL cells with 1.5 mg/ml of Huangqi (Hex) (Components extracted from Huangqi) for 3–5 d results in the expression of β-globin gene in both cell lines and leads to terminal differentiation. Moreover, the apoptosis in HEL cells can be induced by increasing concentration of Huangqi (Hex) to 4.5 mg/ml for 3–5 d. Upregulation of Apaf-1, caspase-3 and acetylcholinesterase (AChE) in HEL cells may play a crucial role in the process of apoptosis. The prospect of inducing expression of adult (β) globin gene and apoptosis selectively in cancer cells is obviously attractive from a therapeutic point of view.

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