The aim of this paper is to provide a theoretical framework to understand how multicellular systems realize functionally integrated physiological entities by organizing their intercellular space. From a perspective centered on physiology and integration, biological systems are often characterized as organized in such a way that they realize metabolic self-production and self-maintenance. The existence and activity of their components rely on the network they realize and on the continuous management of the exchange of matter and energy with their environment. (...) One of the virtues of the organismic approach focused on organization is that it can provide an understanding of how biological systems are functionally integrated into coherent wholes. Organismic frameworks have been primarily developed by focusing on unicellular life. Multicellularity, however, presents additional challenges to our understanding of biological systems, related to how cells are capable to live together in higher-order entities, in such a way that some of their features and behaviors are constrained and controlled by the system they realize. Whereas most accounts of multicellularity focus on cell differentiation and increase in size as the main elements to understand biological systems at this level of organization, we argue that these factors are insufficient to provide an understanding of how cells are physically and functionally integrated in a coherent system. In this paper, we provide a new theoretical framework to understand multicellularity, capable to overcome these issues. Our thesis is that one of the fundamental theoretical principles to understand multicellularity, which is missing or underdeveloped in current accounts, is the functional organization of the intercellular space. In our view, the capability to be organized in space plays a central role in this context, as it enables (and allows to exploit all the implications of) cell differentiation and increase in size, and even specialized functions such as immunity. We argue that the extracellular matrix plays a crucial active role in this respect, as an evolutionary ancient and specific (non-cellular) control subsystem that contributes as a key actor to the functional specification of the multicellular space and to modulate cell fate and behavior. We also analyze how multicellular systems exert control upon internal movement and communication. Finally, we show how the organization of space is involved in some of the failures of multicellular organization, such as aging and cancer. (shrink)

Intercellular communication (IC) is mediated by gap junctions (GJs) and hemichannels, which consist of proteins. This has been particularly well documented for the connexin (Cx) family. Initially, Cxs were thought to be the only proteins capable of GJ formation in vertebrates. About 10 years ago, however, a new GJ‐forming protein family related to invertebrate innexins (Inxs) was discovered in vertebrates, and named the pannexin (Panx) family. Panxs, which are structurally similar to Cxs, but evolutionarily distinct, have been shown (...) to be co‐expressed with Cxs in vertebrates. Both protein families show distinct properties and have their own particular function. Identification of the mechanisms that control Panx channel gating is a major challenge for future work. In this review, we focus on the specific properties and role of Panxs in normal and pathological conditions. (shrink)

I examine critically the application of information‐theoretic ideas to biological communication during embryonic development and in the functioning central nervous system (CNS). I show that intercellular communication relies mostly on simple signals whose role is to effect a selection among predetermined cellular states. Hence, a crucial role is played by cellular memory, which stabilizes such states. Memory in cells is partly located in the nuclear DNA; no less important however is (phenotypic) memory lying in the cell's organelles (...) and compartments. Because of combinatorial effects in gene expression patterns, cell memory is an enormously powerful mechanism, which also underlies plasticity, and thus constitutes the factor unifying genetic determination, plasticity and learning. Communication in the CNS is analyzed in some detail: here, cellular memory is embodied in anatomy (i.e., cell shape) and neurochemistry. These are the major, relatively “static” factors affecting the routing of neural impulses in the adult CNS. In addition, however, faster channeling is also required: action potentials must be directed to their targets along a few of exponentially many paths, and this dynamic routing is crucial for proper operation. I suggest that collective oscillatory modes may play a role in solving this addressing problem, in the same way that the clock signal gates the operation of man‐made computers. BioEssays 25:699–708, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Cell communication plays a key role in multicellular organisms. In developing embryos as in adult organisms, cells communicate by coordinating their differentiation through the establishment and/or renewal of a variety of cell communication channels. Under both these conditions, cells interact by either receptor signalling, surface recognition of specific cell adhesion molecules or transfer of cytoplasmic components through junctional coupling. In recent years, it has become apparent that cells may also communicate through the extracellular release of microvesicles. They may (...) originate as either exosomes from the endosomal compartment upon fusion of multivesicular bodies with the plasma membrane or be shed directly from the plasma membrane via extensions of the cell surface. Microvesicles may disperse over long distances through body fluids and deliver their molecular cargo onto a variety of target cells. As a general rule, the metabolic fate of these cells is determined by the molecular nature of the vesicular cargo, while targeting itself depends on the affinity of the molecules expressed on the enclosing membrane. In this paper, we will be arguing that intercellular vesicular transfer is substantially different from other types of cell communication, allowing cells and molecules to interact on varying levels. Cells interacting via ligand signalling owe their specificity to the steric coupling with cognate receptor molecules. As such, it is a pure molecular process that affects target cells only upon integration into their responding repertoire. In this relationship, coupled cells are reciprocally adapted to each other through the selection of their respective signalling capacities, following exploration of their receptor specificity. Interaction by intercellular vesicles realizes a substantially different type of cell communication. Vesicular traffic allows donor cells to carry out a horizontal type of gene transfer and target this information over long distances via independently controlled mechanisms. Because of this independence, cells interacting via vesicular traffic are not expected to adapt their signalling correspondences, but to control instead the efficiency of their cargo delivery irrespective of the receptor repertoire expressed by the target tissue. In this paper, the multifaceted functions of the intercellular vesicular traffic will be discussed in a multilevel biosemiotic perspective with the aim of unravelling the cellular mechanisms devised by nature to accomplish communication. (shrink)

Ras homolog enriched in the striatum (Rhes) is a striatal enriched protein that promotes the formation of thin membranous tubes resembling tunneling nanotubes (TNT)—“Rhes tunnels”—that connect neighboring cell and transport cargoes: vesicles and proteins between the neuronal cells. Here the literature on TNT‐like structures is reviewed, and the implications of Rhes‐mediated TNT, the mechanisms of its formation, and its potential in novel cell‐to‐cell communication in regulating striatal biology and disease are emphasized. Thought‐provoking ideas regarding how Rhes‐mediated TNT, if it (...) exists, in vivo, would radically change the way neurons communicate in the brain are discussed. (shrink)

Today, the earth is an interconnected globe humming with electronic transmissions-a chattering planet nestled in the provident silence of space. The ethical question is whether this is contributing to authentic human development and helping individuals and peoples to be true to their transcendent destiny. The new media are powerful tools for education, cultural enrichment, commercial activity, political participation, intercultural dialogue and understanding. They also can serve the cause of religion. Yet the new information technology needs to be informed and guided (...) by solidarity in the service of the common good bridging the digital divide within and among nations. The value-laden message of Western secular culture to people and traditional societies in many cases ill-prepared to evaluate it leads to widespread crisis, for example, in regard to marriage and family life. This technology can be a means for solving human problems, promoting the integral development of persons, creating a world governed by justice, peace, and love. It also can help men and women in their age-old search for self-understanding. Like today's world itself, the world of media, including the Internet, has been brought by Christ, inchoately yet truly, within the boundaries of the kingdom of God and placed in service to the word of salvation. (shrink)

This volume provides a comprehensive account of Wilhelm Röpke as a liberal political economist and social philosopher. Wilhelm Röpke was a key protagonist of transatlantic neoliberalism, a prominent public intellectual and a gifted international networker. As an original thinker, he always positioned himself at the interface between political economy and social philosophy, as well as between liberalism and conservatism. Röpke’s endeavors to combine these elements into a coherent whole, as well as his embeddedness in European and American intellectual networks of (...) liberal and conservative thinkers, are a central theme throughout the book. The volume includes papers by international experts from a conference in Geneva on the occasion of the 50th anniversary of Röpke’s passing. The first part focuses on new biographical insights into his exile years in Istanbul and Geneva, while the second part discusses his business cycle theory in the context of the Great Depression, and the third part elaborates on his multifaceted social philosophy. Wilhelm Röpke was among the most important thinkers within the classical liberal revival post-WWII, with intriguing tensions between liberalism and conservatism. A highly recommended volume. –– Peter J. Boettke, 2016-2018 President of the Mont Pèlerin Society and Professor of Economics and Philosophy, George Mason University This important collection of papers provides an in-depth assessment of Wilhelm Röpke’s contributions, placing him in the context of his time. A fine contribution. –– Bruce J. Caldwell, Director of the Center for the History of Political Economy and Research Professor of Economics, Duke University. (shrink)

Intercellular communication is an essential process in all multicellular organisms. During this process, molecules secreted by one cell will bind to a receptor on the cognate cell leading to the subsequent uptake of the receptor‐ligand complex. Once inside, the cell then determines the fate of the receptor‐ligand complex and any other proteins that were endocytosed together. Approximately 80% of endocytosed material is recycled back to the plasma membrane either directly or indirectly via the Golgi apparatus and the remaining (...) 20% is delivered to the lysosome for degradation. Although most pathways have been identified, we still lack understanding on how specificity in sorting of recycling cargos into different pathways is achieved, and how the cell reaches high accuracy of these processes in the absence of clear sorting signals in the bulk of the client proteins. In this review, we will summarize our current understanding of the mechanism behind recycling cargo sorting and propose a model of differential affinities between cargo and cargo receptors/adaptors with regards to iterative sorting in endosomes. (shrink)

Gap junction intercellular communication channels permit the exchange of small regulatory molecules and ions between neighbouring cells and coordinate cellular activity in diverse tissue and organ systems. These channels have short half‐lives and complex assembly and degradation pathways. Much of the recent work elucidating gap junction biogenesis has featured the use of connexins (Cx), the constituent proteins of gap junctions, tagged with reporter proteins such as Green Fluorescent Protein (GFP) and has illuminated the dynamics of channel assembly in (...) live cells by high‐resolution time‐lapse microscopy. With some studies, however, there are potential short‐comings associated with the GFP chimeric protein technologies. A recent report by Gaietta et al., has highlighted the use of recombinant proteins with tetracysteine tags attached to the carboxyl terminus of Cx43, which differentially labels ‘old’ and ‘new’ connexins thus opening up new avenues for studying temporal and spatial localisation of proteins and in situ trafficking events.1 BioEssays 24:876–880, 2002. © 2002 Wiley Periodicals, Inc. (shrink)

Genetic mosaicism has long been linked to aging, and several hypotheses have been proposed to explain the potential connections between mosaicism and susceptibility to cancer. It has been proposed that mosaicism may disrupt tissue homeostasis by affecting intercellular communications and releasing microenvironmental constraints within tissues. The underlying mechanisms driving these tissue‐level influences remain unidentified, however. Here, we present an evolutionary perspective on the interplay between mosaicism and cancer, suggesting that the tissue‐level impacts of genetic mosaicism can be attributed to (...) Indirect Genetic Effects (IGEs). IGEs can increase the level of cellular stochasticity and phenotypic instability among adjacent cells, thereby elevating the risk of cancer development within the tissue. Moreover, as cells experience phenotypic changes in response to challenging microenvironmental conditions, these changes can initiate a cascade of nongenetic alterations, referred to as Indirect non‐Genetic Effects (InGEs), which in turn catalyze IGEs among surrounding cells. We argue that incorporating both InGEs and IGEs into our understanding of the process of oncogenic transformation could trigger a major paradigm shift in cancer research with far‐reaching implications for practical applications. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Books ReceivedThe Ambitions of Curiosity: Understanding the World in Ancient Greece and China. By G.E.R. Lloyd. Cambridge: Cambridge University Press, 2002. Pp. xvi + 175. Price not given.The Art of the Han Essay: Wang Fu's Ch'ien-Fu Lun. By Anne Behnke Kinney. Tempe: Center for Asian Studies, Arizona State University, 1990. Pp. xi + 154. Paper $10.00.The Autobiography of Jamgön Kongtrul: A Gem of Many Colors. By Jamgön Kongtrul Lodrön (...) Thayé and translated by Richard Barron (Chökyi Nyima). Ithaca, New York: Snow Lion Publications, 2003. Pp. xxii + 549. Price not given.Awesome Nightfall: The Life, Times, and Poetry of Saigyō. By William R. LaFleur. Boston: Wisdom Publications, 2003. Pp. xiii + 173. Paper $14.95.Becoming the Compassion Buddha: Tantric Mahamudra for Everyday Life. By Lama Thubten Yeshe, edited by Robina Courtin, and foreword by Geshe Lhundub Sopa. Boston: Wisdom Publications, 2003. Pp. xi + 194. Paper $14.95.Between Two Worlds East and West: An Autobiography. By J. N. Mohanty. New Delhi: Oxford University Press, 2002. Pp. ix + 134. Hardcover RS 525.00.The Chinese Face of Jesus Christ. Edited by Roman Malek, S.V.D. Sankt Augustin, Germany: Institut Monumenta Serica and China-Zentrum; and Nettetal, Germany: Steyler Verlag, 2002. Pp. 391. EUR 40.00.Chinese Medicine in Contemporary China: Plurality and Synthesis. By Volker Scheid. Durham and London: Duke University Press, 2002. Pp. xiv + 407. Hardcover $69.95. Paper $23.95.Confucian Feminist: Memoirs of Zeng Baosun (1893-1978). Translated and adapted by Thomas L. Kennedy. Philadelphia: American Philosophical Society, 2002. Pp. xxi + 170. Price not given.Consciousness Studies: Cross-Cultural Perspectives. By K. Ramakrishna Rao. Jefferson (North Carolina) and London: McFarland and Company, 2002. Pp. 367. Hardcover $65.00.Constituting Communities: Theravāda Buddhism and the Religious Cultures of South and Southeast Asia. Edited by John Clifford Holt, Jacob N. Kinnard, and Jonathan S. Walters. Albany: State University of New York Press, 2003. Pp. viii + 224. Hardcover $65.50. Paper $21.95.Developments in Indian Philosophy from Eighteenth Century Onwards: Classical and Western. By Daya Krishna. Volume X Part 1 of History of Science, Philosophy and Culture in Indian Civilization, edited by D. P. Chattopadhyaya. New [End Page 110] Delhi: Centre for Studies in Civilizations, 2001. Pp. xxiii + 417. Hardcover RS 1200.East and West: Identità e dialogo interculturale. By Giangiorgio Pasqualotto. Venezia: Marsilo Editori, 2003. Pp. 210. EUR 16.00.Effortless Action: Wu-wei as Conceptual Metaphor and Spiritual Ideal in Early China. By Edward Slingerland. New York: Oxford University Press, 2003. Pp. xii + 352. Price not given.Encountering Kā lī: In the Margins, at the Center, in the West. Edited by Rachel Fell McDermott and Jeffrey J. Kripal. Berkeley and Los Angeles: University of California Press, 2003. Pp. xviii + 321. Hardcover $55.00, £37.95. Paper $21.95, £15.95.Encyclopedia of Chinese Philosophy. Edited by Antonio S. Cua. New York and London: Routledge, 2003. Pp. xx + 1020. Hardcover $150.00.Essays on Indian Philosophy. By J. N. Mohanty and edited by Purushottama Bilimoria. New Delhi: Oxford University Press, 2002. Pp. xxxvii + 347. Paper RS 525.00.Faith, Humor, and Paradox. By Ignacio L. Götz. Westport, Connecticut: Praeger Publishers, 2002. Pp. 136. Hardcover $61.95.Four Illusions: Candrakīrti's Advice for Travelers on the Bodhisattva Path. Translated by Karen C. Lang. New York: Oxford University Press, 2003. Pp. xv + 240. Price not given.The Great Awakening: A Buddhist Social Theory. By David R. Loy. Boston: Wisdom Publications, 2003. Pp. 223. Paper $16.95.The Hidden History of The Tibetan Book of the Dead. By Bryan J. Cuevas. New York: Oxford University Press, 2003. Pp. xi + 328. Price not given.Huang Di nei jing su wen: Nature, Knowledge, Imagery in an Ancient Chinese Medical Text. By Paul U. Unschuld. Berkeley and Los Angeles: University of California Press, 2003. Pp. xii + 520. Hardcover $75.00, £52.00.In Dewey's Wake: Unfinished Work of Pragmatic Reconstruction. Edited by William J. Gavin. Albany: State University of New York Press, 2003. Pp. vi + 249. Hardcover $71.50. Paper $23.95.Knowledge and Freedom in Indian Philosophy. By Tara Chatterjea. Lanham, Maryland: Lexington Books, 2002. Pp. xvi + 159. Hardcover... (shrink)

Forty years’ experience as a bacterial geneticist has taught me that bacteria possess many cognitive, computational and evolutionary capabilities unimaginable in the first six decades of the twentieth century. Analysis of cellular processes such as metabolism, regulation of protein synthesis, and DNA repair established that bacteria continually monitor their external and internal environments and compute functional outputs based on information provided by their sensory apparatus. Studies of genetic recombination, lysogeny, antibiotic resistance and my own work on transposable elements revealed multiple (...) widespread bacterial systems for mobilizing and engineering DNA molecules. Examination of colony development and organization led me to appreciate how extensive multicellular collaboration is among the majority of bacterial species. Contemporary research in many laboratories on cell–cell signaling, symbiosis and pathogenesis show that bacteria utilise sophisticated mechanisms for intercellular communication and even have the ability to commandeer the basic cell biology of ‘higher’ plants and animals to meet their own needs. This remarkable series of observations requires us to revise basic ideas about biological information processing and recognise that even the smallest cells are sentient beings. Previous article in issue. (shrink)

Forty years’ experience as a bacterial geneticist has taught me that bacteria possess many cognitive, computational and evolutionary capabilities unimaginable in the first six decades of the twentieth century. Analysis of cellular processes such as metabolism, regulation of protein synthesis, and DNA repair established that bacteria continually monitor their external and internal environments and compute functional outputs based on information provided by their sensory apparatus. Studies of genetic recombination, lysogeny, antibiotic resistance and my own work on transposable elements revealed multiple (...) widespread bacterial systems for mobilizing and engineering DNA molecules. Examination of colony development and organization led me to appreciate how extensive multicellular collaboration is among the majority of bacterial species. Contemporary research in many laboratories on cell–cell signaling, symbiosis and pathogenesis show that bacteria utilise sophisticated mechanisms for intercellular communication and even have the ability to commandeer the basic cell biology of ‘higher’ plants and animals to meet their own needs. This remarkable series of observations requires us to revise basic ideas about biological information processing and recognise that even the smallest cells are sentient beings. (shrink)

For living beings, information is as fundamental as matter or energy. In this paper we show: a) inadequacies of quantitative theories of information, b) how a qualitative analysis leads to a classification of information systems and to a modelling of intercellular communication.From a quantitative point of view, the application in biology of information theories borrowed from communication techniques proved to be disappointing. These theories ignore deliberately the significance of messages, and do not give any definition of information. (...) They refer to quantities, based upon arbitrarily defined probabilistic events. Probability is subjective. The receiver of the message needs to have meta-knowledge of the events. The quantity of information depends on language, coding, and arbitrary definition of disorder. The suggested objectivity is fallacious. (shrink)

The New World of the Organic CodesThe genetic code appeared on Earth at the origin of life, and the codes of culture arrived almost 4 billion years later, at the end of life’s history. Today it is widely assumed that these are the only codes that exist in Nature, and if this were true we would have to conclude that codes are extraordinary exceptions because they appeared only at the beginning and at the end of evolution. In reality, various other (...) organic codes have been discovered in the past few decades.In 1975, the American biochemist Gordon Tomkins published a paper entitled The Metabolic Code. Biological symbolism and the origin of intercellular communication . That was the very first announcement of a new organic code after the discovery of the genetic code, but tragically Tomkins died that very year and his new world of organic symbolism remained unexplored. Some 10 years later, Edward Trifonov started a life-long campaign in favour .. (shrink)

Most cells communicate with their immediate neighbors through the exchange of cytosolic molecules such as ions, second messengers and small metabolites. This activity is made possible by clusters of intercellular channels called gap junctions, which connect adjacent cells. In terms of molecular architecture, intercellular channels consist of two channels, called connexons, which interact to span the plasma membranes of two adjacent cells and directly join the cytoplasm of one cell to another. Connexons are made of structural proteins named (...) connexins, which compose a multigene family. Connexin channels participate in the regulation of signaling between developing and differentiated cell types, and recently there have been some unexpected findings. First, unique ionic‐ and size‐selectivities are determined by each connexin; second, the establishment of intercellular communication is defined by the expression of compatible connexins; third, the discovery of connexin mutations associated with human diseases and the study of knockout mice have illustrated the vital role of cell‐cell communication in a diverse array of tissue functions. (shrink)

Histamine is a multifunctional biogenic amine with relevant roles in intercellular communication, inflammatory processes and highly prevalent pathologies. Histamine biosynthesis depends on a single decarboxylation step, carried out by a PLP-dependent histidine decarboxylase activity (EC 4.1.1.22), an enzyme that still remains to be fully characterized. Nevertheless, during the last few years, important advances have been made in this field, including the generation and validation of the first three-dimensional model of the enzyme, which allows us to revisit previous results (...) and conclusions. This essay provides a comprehensive review of the current knowledge of the structural and functional characteristics of mammalian histidine decarboxylase. BioEssays 27:57–63, 2005. © 2004 Wiley Periodicals, Inc. (shrink)

The polarisation of the embryonic anteroposterior (AP) axis requires the establishment of positional cues with spatial information, and often involves complex intercellular communications, cell adhesion and cell movement. Recent work on several fronts has begun to shed light on how the initial asymmetries are established and maintained. In this review, I discuss the polarisation of the AP axis during Drosophila oogenesis, focusing on the function of the Notch signalling pathway and its relationship to the activation of the epidermal growth (...) factor receptor. I make special reference to some aspects of Notch activity regulation during oogenesis that appear to depart from the canonical pathway. Finally, I hypothesise on possible similarities between these activities of Notch signalling during Drosophila oogenesis and vertebrate somitogenesis. BioEssays 25:781–791, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Bacteria do many things as organized populations. We have recently learned much about the molecular basis of intercellular communication among prokaryotes. Colonies display bacterial capacities for multicellular coordination which can be useful in nature where bacteria predominantly grow as films, chains, mats and colonies. E. coli colonies are organized into differentiated non-clonal populations and undergo complex morphogenesis. Multicellularity regulates many aspects of bacterial physiology, including DNA rearrangement systems. In some bacterial species, colony development involves swarming (active migration of (...) cell groups). Swarm colony development displays precise geometrical controls and periodic phenomena. Motile E. coli cells in semi-solid media form organized patterns due to chemotactic autoaggregation. On poor media, B. subtilis forms branched colonies using group motility and long-range chemical signalling. The significances of bacterial colony patterns thus reside in a deeper understanding of prokaryotic biology and evolution and in experimental systems for studying self-organization and morphogenesis. (shrink)

Information transmission from tumor cells to non‐tumor cells in the surrounding microenvironment via microvesicles is a more recently studied form of intercellular signaling that can have a marked impact on the tumor microenvironment. Tumor‐derived microvesicles (TMVs) are packed with information including signaling proteins and nucleic acids, and can be taken up by target cells, enabling paracrine signaling. While previous research has focused on how vesicles released from pathologic cells differ from normal cells, the heterogeneity that exists within the TMV (...) population itself is not fully characterized, and only beginning to be appreciated. In this review, we summarize current understanding of the biogenesis and roles of shed TMVs in the tumor microenvironment, and speculate on the consequences for tumor cell signaling in light of the hypothesis that there exists variance within the TMV population. The analysis of differential signaling upon cell‐TMV interactions provides insights into potential mechanisms of intercellular communication. (shrink)

The neuregulin gene encodes a series of polypeptide growth factors that can influence the growth state of target vertebrate cells in culture. Recently, three studies have explored the in vivo function of the neuregulin signaling system in mice by disrupting the genes encoding the neuregulin ligand(1) and two of its receptors, ErbB2(2) and ErbB4(3). Each of the genes is essential for development, and aberrations in cardiac and neural development are particularly prominent in mutant embryos. The observed defects, together with the (...) localization of expression of the neuregulin signaling components within these tissues, highlight a paracrine mechanism for neuregulin‐mediated intercellular communication. (shrink)

The fate of root epidermal cells is controlled by a complex interplay of transcriptional regulators, generating a genetically determined, position‐biased arrangement of root hair cells. This pattern is altered during postembryonic development and in response to environmental signals to confer developmental plasticity that acclimates the plant to the prevailing conditions. Based on the hypothesis that events downstream of this initial mechanism can modulate the pattern installed during embryogenesis, we have developed a reaction diffusion model that reproduces the root hair patterning (...) previously observed experimentally. Under all growth conditions, an almost equal spacing between root hair forming cells was observed both in vitro and in silico, indicating that long‐range intercellular communication is crucial for the trichoblasts' decision to form a root hair. We assume that a hair growth promoter (HGP) is upregulated in root‐hair‐forming cells by a trichoblast‐specific component. Once established, HGP production is self‐enhancing. The autocatalytic regulation of HGP is antagonized by an HGP‐produced hair growth inhibitor (HGI). HGI is exported from trichoblasts and diffuses to neighboring cells, where it inhibits further HGP production and promotes the non‐hair cell fate. Under conditions of phosphate deficiency, we hypothesise that HGP production is increased and HGI diffusion rate is reduced, leading to a position‐independent formation of extra root hairs. BioEssays 30:75–81, 2008. © 2007 Wiley Periodicals, Inc. (shrink)

Communication is defined as an interaction between at least two living agents which share a repertoire of signs. These are combined according to syntactic, semantic and context-dependent, pragmatic rules in order to coordinate behavior. This volume deals with the important roles of soil bacteria in parasitic and symbiotic interactions with viruses, plants, animals and fungi. Starting with a general overview of the key levels of communication between bacteria, further reviews examine the various aspects of intracellular as well as (...) intercellular biocommunication between soil microorganisms. This includes the various levels of biocommunication between phages and bacteria, between soil algae and bacteria, and between bacteria, fungi and plants in the rhizosphere, the role of plasmids and transposons, horizontal gene transfer, quorum sensing and quorum quenching, bacterial-host cohabitation, phage-mediated genetic exchange and soil viral ecology. (shrink)

Communication is defined as an interaction between at least two living agents which share a repertoire of signs. These are combined according to syntactic, semantic and context dependent, pragmatic rules in order to coordinate behavior. This volume deals with the important roles of soil bacteria in parasitic and symbiotic interactions with viruses, plants, animals and fungi. Starting with a general overview of the key levels of communication between bacteria, further reviews examine the various aspects of intracellular as well (...) as intercellular biocommunication between soil microorganisms. Th is includes the various levels of biocommunication between phages and bacteria, between soil algae and bacteria, and between bacteria, fungi and plants in the rhizosphere, the role of plasmids and transposons, horizontal gene transfer, quorum sensing and quorum quenching, bacterial-host cohabitation, phage-mediated genetic exchange and soil viral ecology. (shrink)

This article considers categorical perception (CP) as a crucial process involved in all sort of communication throughout the biological hierarchy, i.e. in all of biosemiosis. Until now, there has been consideration of CP exclusively within the functional cycle of perception–cognition–action and it has not been considered the possibility to extend this kind of phenomena to the mere physiological level. To generalise the notion of CP in this sense, I have proposed to distinguish between categorical perception (CP) and categorical sensing (...) (CS) in order to extend the CP framework to all communication processes in living systems, including intracellular, intercellular, metabolic, physiological, cognitive and ecological levels. The main idea is to provide an account that considers the heterarchical embeddedness of many instances of CP and CS. This will take me to relate the hierarchical nature of categorical sensing and perception with the equally hierarchical issues of the “binding problem”, “triadic causality”, the “emergent interpretant” and the increasing semiotic freedom observed in biological and cognitive systems. (shrink)

Chakras are a basic concept of yoga but typically are ignored by scientific research on yoga, probably because descriptions of chakras can appear like a fanciful mythology. Chakras are commonly considered to be centers of concentrated metaphysical energy. Although clear physiological effects exist for yoga practices, no explanation of how chakras influence physiological function has been broadly accepted either in the scientific community or among yoga scholars. This problem is exacerbated by the fact that yoga is based on subjective experience, (...) and practitioners often shun objective descriptions. This essay builds on earlier work hypothesizing that intercellular gap junction connections provide a physiological mechanism underlying subtle energy systems described in yoga as well as other disciplines such as acupuncture. Three physical aspects of chakras are distinguished that are integrated through gap junction mechanisms and are proposed to have arisen during embryological development. Furthermore, electrical conductance associated with a high concentration of gap junctions could generate phenomena that, when subjectively experienced, have the radiant qualities attributed to chakras. This theory provides a scientific rationale for previously unexplained details of chakra theory and offers a new orientation to conceptualizing and studying such subjective phenomena. (shrink)

During tumor evolution, cancer cells use the tumor‐stroma crosstalk to reorganize the microenvironment for maximum robustness of the tumor. The success of immune checkpoint therapy foretells a new cancer therapy paradigm: an effective cancer treatment should not aim to influence the individual components of super complex intracellular interactomes (molecular targeting), but try to disrupt the intercellular interactions between cancer and stromal cells, thus breaking the tumor as a whole. Arguments are provided in favor of a hypothesis that such interactions (...) include formation of synapse‐like structures (interfaces) where the interacting cells are located at a distance of ∼10–15 nm. Within these interfaces, molecules initiating and strengthening the interaction are organized, and allow optimum cross‐signaling; a very confined intercellular space facilitates the concentration of secreted cytokines, enhancing the paracrine cross‐communication. These features of tumors form a druggable cancer hallmark the tumor‐stroma symbiotic crosstalk—which represents a new target for efficient cancer drug discovery. (shrink)

Plants are sessile, highly sensitive organisms that actively compete for environmental resources both above and below the ground. They assess their surroundings, estimate how much energy they need for particular goals, and then realise the optimum variant. They take measures to control certain environmental resources. They perceive themselves and can distinguish between ‘self’ and ‘non-self’. They process and evaluate information and then modify their behaviour accordingly. These highly diverse competences are made possible by parallel sign(alling)-mediated communication processes within the (...) plant body (intraorganismic), between the same, related and different species (interorganismic), and between plants and non-plant organisms (transorganismic). Intraorganismic communication involves sign-mediated interactions within cells (intracellular) and between cells (intercellular). This is crucial in coordinating growth and development, shape and dynamics. Such communication must function both on the local level and between widely separated plant parts. This allows plants to coordinate appropriate response behaviours in a differentiated manner, depending on their current developmental status and physiological influences. Lastly, this volume documents how plant ecosphere inhabitants communicate with each other to coordinate their behavioural patterns, as well as the role of viruses in these highly dynamic interactional networks. (shrink)

We propose that interaction rules derived from polyamine exchange in connected cells may explain the spatio‐temporal organization of gap junctions observed during tissue regeneration and tumorigenesis. We also hypothesize that polyamine exchange can be considered as signal that allows cells to sense the proliferation status of their neighbors. Polyamines (putrescine, spermidine, and spermine) are indeed small aliphatic polycations that serve as fuels to sustain elevated proliferation rates of the order observed in cancer cells. Based on recent reports, we consider here (...) that polyamines can be exchanged through gap junction channels between mammalian cells. Such intercellular exchange of polyamines has critical consequences on the local control of growth. In line with this hypothesis, the complex protein network that keeps polyamine levels finely tuned in mammalian cells can translate polyamine efflux or influx into integrated signals controlling transcription, translation, and cell communications. (shrink)

The immune system does not just fight pathogens but also engages in interactions with beneficial microbes and non-immune cells of the body to harmonize their behavior by means of cytokines, antibodies and effector cells (Dinarello, 2007; Moticka, 2015, pp. 217e226, 261e267). However, the importance of these “housekeeping” functions has not been fully appreciated (Cohen, 2000). In his new book Immunity: The Evolution of an Idea Alfred I. Tauber traces the history of fundamental ideas in immunology and refers to recent advances (...) in the field to overturn the notion that immunity is the ability of an autonomous organism to protect itself against pathogens. Indeed, as suggested by the author, the autonomy of the organism is illusive because individuals develop as holobionts: functionally integrated multispecies consortia (p. 98). Similarly, he suggests that pathogenicity also emerges from the lack of subordination of a microbe to social welfare of the holobiont rather than from context-independent properties of this organism (pp. 165, 181). Emphasizing the contextual character of the parasite and the host, Tauber redefines immunity as an active process of coordination of a cellular ecosystem, which allows this collective to navigate through challenges of the environment and to face demands of the communal living (pp. 10e16). From this point of view, the failure to modulate intercellular interactions by the immune system entails mitigating immunity and impairing resistance to infection and disease (pp. 103e104). Immunity is a groundbreaking work establishing a new framework for understanding the function and activity of the immune system. Its value also lies in the fact that it serves as an important stepping-stone towards an integrated philosophical, ecological and immunological study of our embedment in the microbial world. (shrink)

Community resilience entails the community’s ongoing and developing capacity to account for its vulnerabilities and function amid and recover from disturbance. A holistic and systematic approach of the community on how it uses material and energy resources or how a society educates the members' overtime is required to learn from the past and adapt to the present and future opportunities and threads. Community resilience has a long history in the local communities, which is embedded in their culture and history around (...) shared values and local knowledge based on a dedicated and robust collaboration among diverse groups of the community and the various actors from different backgrounds. The innovative partnership between various actors such as stakeholders, research entities, local communities, and third sector parties is required to overcome the complexities of resiliency building. Using local knowledge to understand the local needs better is crucial in developing local, sustainable solutions and building community resilience over time. (shrink)

Kuala Lumpur is a diverse city representing many different religions and nationalities. Recent government policy has actively promoted unity and cohesion throughout the city; and the country of Malaysia, with the implementation of a programme called 1Malaysia. In this book, the authors investigate the aims of this programme – predominantly to unify the Malaysian society – and how these objectives resonate in the daily spatial practices of the city’s residents. -/- This book argues that elements of urban infrastructure could work (...) as an essential mediator ‘beyond community’, allowing inclusive social structures to be built, despite cultural and religious tensions existing within the city. It builds on the premise of an empirical study which explores the ways in which different communities use the same spaces, supported through the implementation of a theoretical framework which looks at both Western and Islamic conceptualisations of the notion of community. Through the analysis of Kuala Lumpur, this book contributes towards the creation of more inclusive places in multi-ethnic, multi-cultural and multi-religious communities across the world. (shrink)

Many theorists claim that the reactive emotions, even in their private form, are communicative entities. But as widely endorsed as this claim is, it has not been redeemed: the literature lacks a clear and compelling account of the sense in which reactive attitudes qua private mental states are essentially communicative. In this paper, I fill this gap. I propose that it is apt to characterize privately held reactive attitudes as communicative in nature because they, like many paradigmatic forms of (...) class='Hi'>communication, have representational content and the function of evoking uptake of this content in a recipient. (shrink)

In this important volume Habermas outlines the views which form the basis of his critical theory of modern societies. The volume comprises five interlocking essays, which together define the contours of his theory of communication and of his substantive account of social change. ′What is Universal Pragmatics?′ is the best available statement of Habermas′s programme for a theoryof communication based on the analysis of speech acts. In the following two essays Habermas draws on the work of Kohlberg and (...) others to develop a distinctive account of moral consciousness and normative structures. ′Toward a Reconstruction of historical Materialsim′ takes these issues further, offering a wide–ranging reconstruction of Marx′s historical materialsim understood as a theory of social evolution. The final essay focuses on the question of legitimacy and on the legitimation problems faced by modern states. This book is essential reading for anyone concerned with the key questions of social and political theory today. (shrink)

I critically discuss respects in which conceptions of community have featured in African moral-political philosophy over the past 40 years or so. Some of the discussion is in the vein of intellectual history, recounting key theoretical moves for those unfamiliar with the field. However, my discussion is also opinionated, noting prima facie weaknesses with certain positions and presenting others as more promising, particularly relative to prominent Western competitors. There are a variety of forms that African communitarianism has taken and could (...) take in respect of moral status, good character, and just policy, and my aims include arguing that some are more plausible than others and should give more individualist thinkers in Euro-American traditions pause. (shrink)

A satisfactory theory of linguistic communication must explain how it is that, through the interpersonal exchange of auditory, visual, and tactile stimuli, the communicative preconditions for the acquisition of testimonial knowledge regularly come to be satisfied. Without an account of knowledge-yielding communication this success condition for linguistic theorizing is left opaque, and we are left with an incomplete understanding of testimony, and communication more generally, as a source of knowledge. This paper argues that knowledge-yielding communication should (...) be modelled on knowledge itself. It is argued that knowledge-yielding communication occurs iff interlocutors coordinate on truth values in a non-lucky and non-deviant way. This account is able to do significant explanatory work: it sheds light on the nature of referential communication, and it allows us to capture, in an informative way, the sense in which interlocutors must entertain similar propositions in order to communicate successfully. (shrink)

Academic bioethics does not appear to be interested in communication and its ethical concerns unless communication is to do with issues such as capacity, consent, truth telling and confidentiality. In contrast practitioners are interested in actually communicating with their patients and they are often particularly perplexed when it comes to people with profound disabilities where communication appears disrupted. Although some new and not so new communication strategies, and especially intensive interaction, are available, little has been written (...) on either the ethical concerns these may present or the deeper concepts that underpin them. This article explores the practical applications of some of these communication strategies. By engaging these strategies with theology, and specifically Pope John Paul’s Theology of the Body, this article identifies and addresses some significant ethical issues that may arise, notably the risk of dualism and of objectifying the human person. Moreover it provides communication strategies with a rationale that goes beyond practicalities to one based on respect for human dignity, justice and solidarity. (shrink)