scholarly journals Intercellular competition and the inevitability of multicellular aging

2017 ◽  
Vol 114 (49) ◽  
pp. 12982-12987 ◽  
Author(s):  
Paul Nelson ◽  
Joanna Masel
Keyword(s):  
Somatic Cells ◽  
Multicellular Organism ◽  
Double Bind ◽  
Antagonistic Pleiotropy ◽  
Full Understanding ◽  
Effects Of Aging ◽  
Multicellular Organisms ◽  
Somatic Selection

Current theories attribute aging to a failure of selection, due to either pleiotropic constraints or declining strength of selection after the onset of reproduction. These theories implicitly leave open the possibility that if senescence-causing alleles could be identified, or if antagonistic pleiotropy could be broken, the effects of aging might be ameliorated or delayed indefinitely. These theories are built on models of selection between multicellular organisms, but a full understanding of aging also requires examining the role of somatic selection within an organism. Selection between somatic cells (i.e., intercellular competition) can delay aging by purging nonfunctioning cells. However, the fitness of a multicellular organism depends not just on how functional its individual cells are but also on how well cells work together. While intercellular competition weeds out nonfunctional cells, it may also select for cells that do not cooperate. Thus, intercellular competition creates an inescapable double bind that makes aging inevitable in multicellular organisms.

scholarly journals Do Somatic Cells Really Sacrifice Themselves? Why an Appeal to Coercion May be a Helpful Strategy in Explaining the Evolution of Multicellularity

2021 ◽  
Author(s):  
Adrian Stencel ◽  
Javier Suárez
Keyword(s):  
Present Article ◽  
Evolutionary Biology ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Somatic Cells ◽  
Next Generation ◽  
Inclusive Fitness Theory ◽  
Germline Cells ◽  
Multicellular Organisms

AbstractAn understanding of the factors behind the evolution of multicellularity is one of today’s frontiers in evolutionary biology. This is because multicellular organisms are made of one subset of cells with the capacity to transmit genes to the next generation (germline cells) and another subset responsible for maintaining the functionality of the organism, but incapable of transmitting genes to the next generation (somatic cells). The question arises: why do somatic cells sacrifice their lives for the sake of germline cells? How is germ/soma separation maintained? One conventional answer refers to inclusive fitness theory, according to which somatic cells sacrifice themselves altruistically, because in so doing they enhance the transmission of their genes by virtue of their genetic relatedness to germline cells. In the present article we will argue that this explanation ignores the key role of policing mechanisms in maintaining the germ/soma divide. Based on the pervasiveness of the latter, we argue that the role of altruistic mechanisms in the evolution of multicellularity is limited and that our understanding of this evolution must be enriched through the consideration of coercion mechanisms.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

From Organizations of Processes to Organisms and Other Biological Individuals

2018 ◽  
Author(s):  
Argyris Arnellos
Keyword(s):  
Multicellular Organism ◽  
Collaborative Networks ◽  
Biological Role ◽  
Regulatory Processes ◽  
Different Types ◽  
Organizational Framework

The emphasis on the collaborative dimension of life overlooks the importance of biological individuals (conceived of as integrated, self-maintaining organizations) in the build-up of more complex collaborative networks in the course of evolution. This chapter proposes a process-based organizational ontology for biology, according to which the essential features of unicellular organismicality are captured by a self-maintaining organization of processes integrated by means of a special type of collaboration (realized through regulatory processes entailing an indispensable interdependence) between its constitutive and its interactive aspects. This ontology is then used to describe different types of collaborations among cells and to suggest the type that yields a multicellular organism. The proposed organizational framework enables us to critically assess hypercollaborative views of life, especially issues related to the distinction between biological individuals and organisms and between life and non-life, without however underestimating the central biological role of collaboration.

scholarly journals The Road More Travelled: The Differential Effects of Spatial Experience in Young and Elderly Participants

2021 ◽  
Vol 18 (2) ◽  
pp. 709
Author(s):  
Antonella Lopez ◽  
Alessandro Germani ◽  
Luigi Tinella ◽  
Alessandro Oronzo Caffò ◽  
Albert Postma ◽  
...  
Keyword(s):  
Mental Representations ◽  
Spatial Relations ◽  
The Elderly ◽  
The Road ◽  
Socio Demographic Factors ◽  
Effects Of Aging ◽  
Coordinate Spatial Relations ◽  
Categorical Spatial Relations ◽  
The Relationship

Our spatial mental representations allow us to give refined descriptions of the environment in terms of the relative locations and distances between objects and landmarks. In this study, we investigated the effects of familiarity with the everyday environment, in terms of frequency of exploration and mode of transportation, on categorical and coordinate spatial relations, on young and elderly participants, controlling for socio-demographic factors. Participants were tested with a general anamnesis, a neuropsychological assessment, measures of explorations and the Landmark Positioning on a Map task. The results showed: (a) a modest difference in performance with categorical spatial relations; (b) a larger difference in coordinate spatial relations; (c) a significant moderating effect of age on the relationship between familiarity and spatial relations, with a stronger relation among the elderly than the young. Ceteris paribus, the role of direct experience with exploring their hometown on spatial mental representations appeared to be more important in the elderly than in the young. This advantage appears to make the elderly wiser and likely protects them from the detrimental effects of aging on spatial mental representations.

scholarly journals Pannexins and Connexins: Their Relevance for Oocyte Developmental Competence

2021 ◽  
Vol 22 (11) ◽  
pp. 5918
Author(s):  
Paweł Kordowitzki ◽  
Gabriela Sokołowska ◽  
Marta Wasielak-Politowska ◽  
Agnieszka Skowronska ◽  
Mariusz T. Skowronski
Keyword(s):  
Assisted Reproductive Technologies ◽  
Mammalian Species ◽  
Atp Release ◽  
Reproductive Technologies ◽  
High Energy ◽  
Developmental Competence ◽  
Physiological Processes ◽  
Protein Group ◽  
Multicellular Organisms

The oocyte is the major determinant of embryo developmental competence in all mammalian species. Although fundamental advances have been generated in the field of reproductive medicine and assisted reproductive technologies in the past three decades, researchers and clinicians are still trying to elucidate molecular factors and pathways, which could be pivotal for the oocyte’s developmental competence. The cell-to-cell and cell-to-matrix communications are crucial not only for oocytes but also for multicellular organisms in general. This latter mentioned communication is among others possibly due to the Connexin and Pannexin families of large-pore forming channels. Pannexins belong to a protein group of ATP-release channels, therefore of high importance for the oocyte due to its requirements of high energy supply. An increasing body of studies on Pannexins provided evidence that these channels not only play a role during physiological processes of an oocyte but also during pathological circumstances which could lead to the development of diseases or infertility. Connexins are proteins that form membrane channels and gap-junctions, and more precisely, these proteins enable the exchange of some ions and molecules, and therefore they do play a fundamental role in the communication between the oocyte and accompanying cells. Herein, the role of Pannexins and Connexins for the processes of oogenesis, folliculogenesis, oocyte maturation and fertilization will be discussed and, at the end of this review, Pannexin and Connexin related pathologies and their impact on the developmental competence of oocytes will be provided.

scholarly journals Effects of Dysbiosis and Dietary Manipulation on the Digestive Microbiota of a Detritivorous Arthropod

2021 ◽  
Vol 9 (1) ◽  
pp. 148
Author(s):  
Marius Bredon ◽  
Elisabeth Depuydt ◽  
Lucas Brisson ◽  
Laurent Moulin ◽  
Ciriac Charles ◽  
...  
Keyword(s):  
Crucial Role ◽  
Structure And Function ◽  
Ecological Interactions ◽  
Dietary Manipulation ◽  
Biotic Factors ◽  
Abiotic And Biotic Factors ◽  
And Function ◽  
Multicellular Organisms ◽  
Over Time

The crucial role of microbes in the evolution, development, health, and ecological interactions of multicellular organisms is now widely recognized in the holobiont concept. However, the structure and stability of microbiota are highly dependent on abiotic and biotic factors, especially in the gut, which can be colonized by transient bacteria depending on the host’s diet. We studied these impacts by manipulating the digestive microbiota of the detritivore Armadillidium vulgare and analyzing the consequences on its structure and function. Hosts were exposed to initial starvation and then were fed diets that varied the different components of lignocellulose. A total of 72 digestive microbiota were analyzed according to the type of the diet (standard or enriched in cellulose, lignin, or hemicellulose) and the period following dysbiosis. The results showed that microbiota from the hepatopancreas were very stable and resilient, while the most diverse and labile over time were found in the hindgut. Dysbiosis and selective diets may have affected the host fitness by altering the structure of the microbiota and its predicted functions. Overall, these modifications can therefore have effects not only on the holobiont, but also on the “eco-holobiont” conceptualization of macroorganisms.

scholarly journals Evolution of the hedgehog Gene Family

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 965-972 ◽  
Author(s):  
Sudhir Kumar ◽  
Kristi A Balczarek ◽  
Zhi-Chun Lai
Keyword(s):  
Intercellular Communication ◽  
Short Range ◽  
Gene Duplications ◽  
Future Directions ◽  
Amino Terminal ◽  
Terminal Fragment ◽  
Carboxyl Terminal ◽  
Multicellular Organisms ◽  
Amino Terminal Fragment

Abstract Effective intercellular communication is an important feature in the development of multicellular organisms. Secreted hedgehog (hh) protein is essential for both long- and short-range cellular signaling required for body pattern formation in animals. In a molecular evolutionary study, we find that the vertebrate homologs of the Drosophila hh gene arose by two gene duplications: the first gave rise to Desert hh, whereas the second produced the Indian and Sonic hh genes. Both duplications occurred before the emergence of vertebrates and probably before the evolution of chordates. The amino-terminal fragment of the hh precursor, crucial in long- and short-range intercellular communication, evolves two to four times slower than the carboxyl-terminal fragment in both Drosophila hh and its vertebrate homologues, suggesting conservation of mechanism of hh action in animals. A majority of amino acid substitutions in the amino- and carboxyl-terminal fragments are conservative, but the carboxyl-terminal domain has undergone extensive insertion-deletion events while maintaining its autocleavage protease activity. Our results point to similarity of evolutionary constraints among sites of Drosophila and vertebrate hh homologs and suggest some future directions for understanding the role of hh genes in the evolution of developmental complexity in animals.

scholarly journals The Role of 5-Lipoxygenase and Leukotrienes in Shock and Ischemia-Reperfusion Injury

2007 ◽  
Vol 7 ◽  
pp. 56-74 ◽  
Author(s):  
Antonietta Rossi ◽  
Carlo Pergola ◽  
Salvatore Cuzzocrea ◽  
Lidia Sautebin
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Biological Activities ◽  
Ischemia Reperfusion ◽  
Targeted Disruption ◽  
Pathological Conditions ◽  
Metabolic Products ◽  
Important Regulator ◽  
Multicellular Organisms

The leukotrienes (LTs) are metabolic products of arachidonic acid via the 5-lipoxygenase (5-LO) pathway. The biological activities of LTs suggest that they are mediators of acute inflammatory and immediate hypersensitivity responses. In particular, the 5-LO activation has been proposed to be an important regulator for pathogenesis in multicellular organisms. The role of LTs in tissue damage, associated with septic and nonseptic shock and ischemia-reperfusion, has been extensively studied by the use of 5-LO inhibitors, receptor antagonists, and mice with a targeted disruption of the 5-LO gene (5-LOKO). In particular, several data indicate that LTs regulate neutrophil trafficking in damaged tissue in shock and ischemia-reperfusion, mainly through the modulation of adhesion molecule expression. This concept may provide new insights into the interpretation of the protective effect of 5-LO inhibition, which may be useful in the therapy of pathological conditions associated with septic and nonseptic shock and ischemia-reperfusion injury.

scholarly journals Glycosphingolipids are required for sorting melanosomal proteins in the Golgi complex

2001 ◽  
Vol 155 (3) ◽  
pp. 369-380 ◽  
Author(s):  
Hein Sprong ◽  
Sophie Degroote ◽  
Tijs Claessens ◽  
Judith van Drunen ◽  
Viola Oorschot ◽  
...  
Keyword(s):  
Golgi Complex ◽  
Protein Transport ◽  
Transmembrane Domain ◽  
Direct Pathway ◽  
Mouse Melanoma Cell ◽  
Multicellular Organisms ◽  
Rate Limiting ◽  
Tyrosinase Related Protein ◽  
Mouse Melanoma Cell Line

A;lthough glycosphingolipids are ubiquitously expressed and essential for multicellular organisms, surprisingly little is known about their intracellular functions. To explore the role of glycosphingolipids in membrane transport, we used the glycosphingolipid-deficient GM95 mouse melanoma cell line. We found that GM95 cells do not make melanin pigment because tyrosinase, the first and rate-limiting enzyme in melanin synthesis, was not targeted to melanosomes but accumulated in the Golgi complex. However, tyrosinase-related protein 1 still reached melanosomal structures via the plasma membrane instead of the direct pathway from the Golgi. Delivery of lysosomal enzymes from the Golgi complex to endosomes was normal, suggesting that this pathway is not affected by the absence of glycosphingolipids. Loss of pigmentation was due to tyrosinase mislocalization, since transfection of tyrosinase with an extended transmembrane domain, which bypassed the transport block, restored pigmentation. Transfection of ceramide glucosyltransferase or addition of glucosylsphingosine restored tyrosinase transport and pigmentation. We conclude that protein transport from Golgi to melanosomes via the direct pathway requires glycosphingolipids.

THE ROLE OF COW PROCESSING IN IMPROVEMENT MILK QUALITY

2018 ◽  
Vol 1 (1) ◽  
pp. 59-63
Author(s):  
G. A. Larionov ◽  
◽  
O. Yu. Сhecheneshkina ◽  
E. S. Yatrusheva ◽  
N. I. Yendierov ◽  
...  
Keyword(s):  
Somatic Cell Count ◽  
Somatic Cells ◽  
Cow Milk ◽  
Microbiological Contamination ◽  
High Quality ◽  
Quality Of Milk ◽  
Correct Understanding ◽  
Main Factor

The main factor of determining the level of sanitary and hygienic indicators of the quality of milk produced is the hygiene of milking cows. The study of the role of hygiene of milking is of great importance for a correct understanding of the ways of solving the problem of obtaining high quality milk. Special attention of scientists and practitioners in recent years are focused on the development and implementation of highly effective detergents and disinfectants in the production of milk of cows. Many researchers and practitioners have directed their work to developing measures to prevent the entry of pathogenic microflora into milk during and after milking cows. In spite of many researches carried out, aimed at controlling the number of somatic cells in milk with the use of different products based on lactic acid, chlorhexidine and iodine, the problem of high quality milk production remains unresolved. In our work results of researches on the use of probiotic means for treatment of udders of cows are given. Processing the udder of cows with probiotic means before milking by Skin Cleaner, after milking by PIP Cow Teat Cleaner reduced the amount of somatic cells in cow milk 12,8-84,0%. The use of probiotic means Biomastim lowed somatic cell count of 18,4-51,9%. Microbiological contamination of milk using probiotic means for processing the udder before milking Skin Cleaner, after milking PIP Cow Teat Cleaner decreased 4,9- 70,4 times. The application of probiotic means Biomastim after milking on the teats led to the decrease in milk of cows QMAFAnM 5,0-6,6 times.

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