Symbiosis and Evolution: A Brief Guide to Recent Literature

Margulis, Lynn; Bermudes, David

doi:10.1007/978-3-642-73154-9_11

Cited by 10 publications

(12 citation statements)

References 7 publications

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“…The endosymbiotic theory of organellar origins suggests that chloroplasts arose from an endosymbiosis of once free-living photosynthetic bacteria with a subsequent incorporation of a considerable part of the bacterial genome into the host's nuclear genome (30,31). The degree of gene transfer or loss of genetic material from the endosymbiont varies considerably, especially when comparing land plants and green algae to the nongreen algae (28).…”

Section: Discussionmentioning

confidence: 99%

Chloroplast genes are expressed during intracellular symbiotic association of Vaucheria litorea plastids with the sea slug Elysia chlorotica.

Mujer

Andrews

Manhart

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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The marine slug Elysia chlorotica (Gould) forms an intracellular symbiosis with photosynthetically active chloroplasts from the chromophytic alga Vaucheria litorea (C. Agardh). This symbiotic association was characterized over a period of 8 months during which E. chlorotica was deprived of V. litorea but provided with light and CO2. The fine structure of the symbiotic chloroplasts remained intact in E. chlorotica even after 8 months of starvation as revealed by electron microscopy. Southern blot analysis of total DNA from E. chlorotica indicated that algal genes, i.e., rbcL, rbcS, psaB, psbA, and 16S rRNA are present in the animal. These genes are typically localized to the plastid genome in higher plants and algae except rbcS, which is nuclear-encoded in higher plants and green (chlorophyll a/b) algae. Our analysis suggests, however, that similar to the few other chromophytes (chlorophyll a/c) examined, rbcS is chloroplast encoded in V. litorea. Levels of psbA transcripts remained constant in E. chlorotica starved for 2 and 3 months and then gradually declined over the next 5 months corresponding with senescence of the animal in culture and in nature. The RNA synthesis inhibitor 6-methylpurine reduced the accumulation of psbA transcripts confirming active transcription. In contrast to psbA, levels of 16S rRNA transcripts remained constant throughout the starvation period. The levels of the photosystem II proteins, Dl and CP43, were high at 2 and 4 months of starvation and remained constant at a lower steady-state level after 6 months. In contrast, D2 protein levels, although high at 2 and 4 months, were very low at all other periods of starvation. At 8 months, de novo synthesis of several thylakoid membrane-enriched proteins, including Dl, still occurred. To our knowledge, these results represent the first molecular evidence for active transcription and translation of algal chloroplast genes in an animal host and are discussed in relation to the endosymbiotic theory of eukaryote origins.The ascoglossan sea slug Elysia chlorotica (Gould) forms an intracellular symbiosis with chloroplasts of the filamentous chromophytic alga Vaucheria litorea (C. Agardh) (1, 2). The animal resembles a dark green leaf and is capable of photoautotrophic CO2 fixation as a result of the high density of chloroplasts dispersed throughout its extensive digestive system (1, 3, 4). The photosynthetic sea slug survives in laboratory aquaria for 8-9 months when provided with only light and CO2 (starved); a time period similar to its life cycle in nature. The symbiotic association is not inherited since the plastids are not transmitted in the eggs (5). Instead, chloroplast symbiosis is reestablished with each new generation of sea slugs (1, 6, 7). Acquisition of chloroplast symbionts begins immediately following metamorphosis from the veliger stage when juvenile sea slugs begin to feed on V litorea cells (1, 2). Once ingested, the chloroplasts are phagocytically incorporated into the cytoplasm of one of two morphologically distinct...

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Section: Discussionmentioning

confidence: 99%

Chloroplast genes are expressed during intracellular symbiotic association of Vaucheria litorea plastids with the sea slug Elysia chlorotica.

Mujer

Andrews

Manhart

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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“…Throughout time, physicians have tried to identify specific changes in cells during the development of pathological processes. In 1894, the German scientist R. Altman first discovered subcellular structures, which the German histologist K. Benda in 1898 called mitochondria [68][69][70][71][72]. The endoplasmic reticulum was first described by the American biologist K.R.…”

Section: Mental and Somatic Factors: A Brief History Of The Issuementioning

confidence: 99%

“…Porter in 1945. By the middle of the 20th century, a symbiotic theory of the origin of mitochondria was created, according to which the descendants of certain groups of bacteria entered into symbiosis with the ancestors of modern eukaryotes [71][72][73][74][75][76][77]. According to this theory, in the course of evolution, endosymbiont bacteria turned into semiautonomous bioenergetic stations of cells capable of producing ATP and mitochondrial membrane potential.…”

Section: Mental and Somatic Factors: A Brief History Of The Issuementioning

confidence: 99%

Causal Relationship between Physiological and Pathological Processes in the Brain and in the Gastrointestinal Tract: The Brain–Intestine Axis

Реутов

Sorokina

2022

BIOPHYSICS

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The brain and gastrointestinal tract are the most important organs responsible for detecting, transmitting, integrating, and responding to signals coming from the internal and external environment. A bidirectional system of neurohumoral communication (the "intestine-brain" axis) combines the activity of the intestine and brain (or brain and intestine) of a person. It affects human development and behavior. This paper analyzes the literature data on the existence of a relationship between the central and enteral nervous systems. Based on data on the number of neurons in the enteral nervous system (approximately 250 million nerve cells), the concept of a "second brain" in the intestine has been proposed in foreign literature, which, by its influence on the brain, can have a more powerful influence than the spinal cord (approximately 10 million neurons) with its autonomic nervous system. However, it turned out that Russian scientists, academicians of the Academy of Sciences of the Soviet Union I.P. Pavlov, K.M. Bykov, and A.M. Ugolev, analyzed cortical-visceral relationships in the 20th century and wrote about the existence of a connection between the central and enteral nervous systems. One of the urgent problems of modern physiology, pathophysiology, biophysics, biochemistry, and medicine is to clarify the causal relationship between the central and enteral nervous systems, as well as between neurological, mental, and gastrointestinal diseases in order to combine the efforts of specialists of various medical and biological profiles to solve urgent medical problems.

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“…Over time, a trend emerged to accommodate a more pluralistic narrative compared to the major tenets of the Modern Synthesis [ 27 ]. Although not the first to champion it, Margulis [ 28 , 29 ] became a vigorous proponent of incorporating symbiogensis and endosymbiosis into the evolutionary narrative by outlining an organelle genesis theory [ 30 ]. McClintock played a similar crucial role with her illuminating work on transposable elements [ 31 ].…”

Section: Darwin the Modern Synthesis And Beyondmentioning

confidence: 99%

Cognition, Information Fields and Hologenomic Entanglement: Evolution in Light and Shadow

Miller

2016

Biology

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As the prime unification of Darwinism and genetics, the Modern Synthesis continues to epitomize mainstay evolutionary theory. Many decades after its formulation, its anchor assumptions remain fixed: conflict between macro organic organisms and selection at that level represent the near totality of any evolutionary narrative. However, intervening research has revealed a less easily appraised cellular and microbial focus for eukaryotic existence. It is now established that all multicellular eukaryotic organisms are holobionts representing complex collaborations between the co-aligned microbiome of each eukaryote and its innate cells into extensive mixed cellular ecologies. Each of these ecological constituents has demonstrated faculties consistent with basal cognition. Consequently, an alternative hologenomic entanglement model is proposed with cognition at its center and conceptualized as Pervasive Information Fields within a quantum framework. Evolutionary development can then be reconsidered as being continuously based upon communication between self-referential constituencies reiterated at every scope and scale. Immunological reactions support and reinforce self-recognition juxtaposed against external environmental stresses.

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Symbiosis and Evolution: A Brief Guide to Recent Literature

Cited by 10 publications

References 7 publications

Chloroplast genes are expressed during intracellular symbiotic association of Vaucheria litorea plastids with the sea slug Elysia chlorotica.

Chloroplast genes are expressed during intracellular symbiotic association of Vaucheria litorea plastids with the sea slug Elysia chlorotica.

Causal Relationship between Physiological and Pathological Processes in the Brain and in the Gastrointestinal Tract: The Brain–Intestine Axis

Cognition, Information Fields and Hologenomic Entanglement: Evolution in Light and Shadow

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