scholarly journals Neural architecture and regeneration in the acoel Hofstenia miamia

2020 ◽  
Vol 287 (1931) ◽  
pp. 20201198
Author(s):  
Ryan E. Hulett ◽  
Deirdre Potter ◽  
Mansi Srivastava
Keyword(s):  
Expression Patterns ◽  
Bilateral Symmetry ◽  
Cell Types ◽  
Neural Cells ◽  
Animal Evolution ◽  
Nervous Systems ◽  
Major Transition ◽  
History Of ◽  
Neural Anatomy ◽  
Insight Into

The origin of bilateral symmetry, a major transition in animal evolution, coincided with the evolution of organized nervous systems that show regionalization along major body axes. Studies of Xenacoelomorpha, the likely outgroup lineage to all other animals with bilateral symmetry, can inform the evolutionary history of animal nervous systems. Here, we characterized the neural anatomy of the acoel Hofstenia miamia . Our analysis of transcriptomic data uncovered orthologues of enzymes for all major neurotransmitter synthesis pathways. Expression patterns of these enzymes revealed the presence of a nerve net and an anterior condensation of neural cells. The anterior condensation was layered, containing several cell types with distinct molecular identities organized in spatially distinct territories. Using these anterior cell types and structures as landmarks, we obtained a detailed timeline for regeneration of the H . miamia nervous system, showing that the anterior condensation is restored by eight days after amputation. Our work detailing neural anatomy in H . miamia will enable mechanistic studies of neural cell type diversity and regeneration and provide insight into the evolution of these processes.

scholarly journals A flagellate-to-amoeboid switch in the closest living relatives of animals

2020 ◽  
Author(s):  
Thibaut Brunet ◽  
Marvin Albert ◽  
William Roman ◽  
Danielle C. Spitzer ◽  
Nicole King
Keyword(s):  
Epithelial Cells ◽  
Common Ancestor ◽  
Cell Types ◽  
Cell Phenotype ◽  
Last Common Ancestor ◽  
Animal Evolution ◽  
Amoeboid Motility ◽  
History Of ◽  
Different Cell Types ◽  
Amoeboid Cells

The evolution of different cell types was a key process of early animal evolution1–3. Two fundamental cell types, epithelial cells and amoeboid cells, are broadly distributed across the animal tree of life4,5 but their origin and early evolution are unclear. Epithelial cells are polarized, have a fixed shape and often bear an apical cilium and microvilli. These features are shared with choanoflagellates – the closest living relatives of animals – and are thought to have been inherited from their last common ancestor with animals1,6,7. The deformable amoeboid cells of animals, on the other hand, seem strikingly different from choanoflagellates and instead evoke more distantly related eukaryotes, such as diverse amoebae – but it has been unclear whether that similarity reflects common ancestry or convergence8. Here, we show that choanoflagellates subjected to spatial confinement differentiate into an amoeboid phenotype by retracting their flagella and microvilli, generating blebs, and activating myosin-based motility. Choanoflagellate cell crawling is polarized by geometrical features of the substrate and allows escape from confined microenvironments. The confinement-induced amoeboid switch is conserved across diverse choanoflagellate species and greatly expands the known phenotypic repertoire of choanoflagellates. The broad phylogenetic distribution of the amoeboid cell phenotype across animals9–14 and choanoflagellates, as well as the conserved role of myosin, suggests that myosin-mediated amoeboid motility was present in the life history of their last common ancestor. Thus, the duality between animal epithelial and crawling cells might have evolved from a temporal phenotypic switch between flagellate and amoeboid forms in their single-celled ancestors3,15,16.

scholarly journals Sociality emerges from solitary behaviours and reproductive plasticity in the orchid bee Euglossa dilemma

2019 ◽  
Vol 286 (1906) ◽  
pp. 20190588 ◽  
Author(s):  
Nicholas W. Saleh ◽  
Santiago R. Ramírez
Keyword(s):  
Gene Expression ◽  
Social Behaviour ◽  
Expression Patterns ◽  
Strong Support ◽  
Life Cycles ◽  
Orchid Bee ◽  
Insect Societies ◽  
Major Transition ◽  
History Of ◽  
Worker Castes

The evolution of eusociality and sterile worker castes represents a major transition in the history of life. Despite this, little is known about the mechanisms involved in the initial transition from solitary to social behaviour. It has been hypothesized that plasticity from ancestral solitary life cycles was coopted to create queen and worker castes in insect societies. Here, we tested this hypothesis by examining gene expression involved in the transition from solitary to social behaviour in the orchid bee Euglossa dilemma . To this end, we conducted observations that allowed us to classify bees into four distinct categories of solitary and social behaviour. Then, by sequencing brain and ovary transcriptomes from these behavioural phases, we identified gene expression changes overlapping with socially associated genes across multiple eusocial lineages. We find that genes involved in solitary E. dilemma ovarian plasticity overlap extensively with genes showing differential expression between fertile and sterile workers—or between queens and workers in other eusocial bees. We also find evidence that sociality in E. dilemma reflects gene expression patterns involved in solitary foraging and non-foraging nest care behaviours. Our results provide strong support for the hypothesis that eusociality emerges from plasticity found across solitary life cycles.

scholarly journals Rimbp, a New Marker for the Nervous System of the Tunicate Ciona robusta

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1006
Author(s):  
Ugo Coppola ◽  
Paola Olivo ◽  
Enrico D’Aniello ◽  
Christopher J. Johnson ◽  
Alberto Stolfi ◽  
...  
Keyword(s):  
Nervous System ◽  
Active Zone ◽  
Expression Patterns ◽  
Regulatory Elements ◽  
Animal Evolution ◽  
Endogenous Expression ◽  
Presynaptic Mechanisms ◽  
Larval Nervous System ◽  
History Of ◽  
Presynaptic Active Zone

Establishment of presynaptic mechanisms by proteins that regulate neurotransmitter release in the presynaptic active zone is considered a fundamental step in animal evolution. Rab3 interacting molecule-binding proteins (Rimbps) are crucial components of the presynaptic active zone and key players in calcium homeostasis. Although Rimbp involvement in these dynamics has been described in distantly related models such as fly and human, the role of this family in most invertebrates remains obscure. To fill this gap, we defined the evolutionary history of Rimbp family in animals, from sponges to mammals. We report, for the first time, the expression of the two isoforms of the unique Rimbp family member in Ciona robusta in distinct domains of the larval nervous system. We identify intronic enhancers that are able to drive expression in different nervous system territories partially corresponding to Rimbp endogenous expression. The analysis of gene expression patterns and the identification of regulatory elements of Rimbp will positively impact our understanding of this family of genes in the context of Ciona embryogenesis.

scholarly journals The unique neuronal structure and neuropeptide repertoire in the ctenophore Mnemiopsis leidyi shed light on the evolution of animal nervous systems

2021 ◽  
Author(s):  
Maria Sachkova ◽  
Eva-Lena Nordmann ◽  
Joan J Soto Angel ◽  
Yasmin Meeda ◽  
Bartlomiej Gorski ◽  
...  
Keyword(s):  
Neuronal Cell ◽  
Cell Types ◽  
Sensory Cells ◽  
Mnemiopsis Leidyi ◽  
Swimming Velocity ◽  
Neuronal Structure ◽  
Nervous Systems ◽  
Nerve Net ◽  
Neuronal Genes ◽  
History Of

The ctenophore nerve net represents one of the earliest evolved nervous system of animals. Due to the uncertainties of their phylogenetic placement of ctenophores and the absence of several key bilaterian neuronal genes, it has been hypothesized that their neurons have evolved independently. Whether this is indeed the case remains unclear, and thus the evolutionary history of neurons is still contentious. Here, we have characterized the neuropeptide repertoire of the ctenophore Mnemiopsis leidyi. Using the machine learning NeuroPID tool1 129 new putative neuropeptide precursors were predicted. Sixteen of them are detected in the subepithelial nerve net (SNN), aboral organ (AO) and epithelial sensory cells (ESC) of early cydippid-stage M. leidyi by in situ hybridization (ISH) and immunohistochemistry (IHC). Four of these neuropeptides increase the animals swimming velocity in a behavioural essay. The new neuropeptides were used as markers to identify neuronal cell types in single cell transcriptomic data2. To unravel the neuronal architecture, we 3D reconstructed the SNN underlying the comb plates using serial block-face scanning electron microscopy (SBF-SEM). For the first time, we confirm a more than 100 years old hypothesis about anastomoses between neurites of the same cell in ctenophores and reveal that they occur through a continuous membrane. Our findings reveal the unique neuronal structure and neuropeptide repertoire of ctenophores and are important for reconstructing the evolutionary origin of animal neurons and nervous systems.

The Subaltern Speak- A Study On The Culture Of The Arunachalis With Special Reference To Mamang Dai’s The Legends Of Pensam

2019 ◽  
Vol 5 (4) ◽  
pp. 14-20
Author(s):  
Ms. Cheryl Antonette Dumenil ◽  
Dr. Cheryl Davis
Keyword(s):  
Special Reference ◽  
Small World ◽  
Natural World ◽  
Arunachal Pradesh ◽  
North East India ◽  
North East ◽  
Shared History ◽  
History Of ◽  
And Gender ◽  
Insight Into

North- East India is an under veiled region with an awe-inspiring landscape, different groups of ethnic people, their culture and heritage. Contemporary writers from this region aspire towards a vision outside the tapered ethnic channel, and they represent a shared history. In their writings, the cultural memory is showcased, and the intensity of feeling overflows the labour of technique and craft. Mamang Dai presents a rare glimpse into the ecology, culture, life of the tribal people and history of the land of the dawn-lit mountains, Arunachal Pradesh, through her novel The Legends of Pensam. The word ‘Pensam’ in the title means ‘in-between’,  but it may also be interpreted as ‘the hidden spaces of the heart’. This is a small world where anything can happen. Being adherents of the animistic faith, the tribes here believe in co-existence with the natural world along with the presence of spirits in their forests and rivers. This paper attempts to draw an insight into the culture and gender of the Arunachalis with special reference to The Legends of Pensam by Mamang Dai.

Collected Documents on the History of the Pskov Orthodox Mission: A Recent Publication

2018 ◽  
pp. 306-312
Author(s):  
Veniamin F. Zima ◽  
Keyword(s):  
Personal Data ◽  
Prisoners Of War ◽  
Inner Life ◽  
Great Patriotic War ◽  
Occupied Territories ◽  
History Of ◽  
Underground Resistance ◽  
The Baltic ◽  
The Church ◽  
Insight Into

The reviewed work is devoted to a significant, and yet little-studied in both national and foreign scholarship, issue of the clergy interactions with German occupational authorities on the territory of the USSR in the days of the Great Patriotic War. It introduces into scientific use historically significant complex of documents (1941-1945) from the archive of the Office of the Metropolitan Sergius (Voskresensky) of Vilnius and Lithuania, patriarchal exarch in Latvia and Estonia, and also records from the investigatory records on charges against clergy and employees concerned in the activities of the Pskov Orthodox Mission (1944-1990). Documents included in the publication are stored in the archives of Moscow, St. Petersburg, Estonia, Lithuania, Leningrad, Novgorod, and Pskov regions. They allow some insight into nature, forms, and methods of the Nazi occupational regime policies in the conquered territories (including policies towards the Church). The documents capture religious policies of the Nazis and inner life of the exarchate, describe actual situation of population and clergy, management activities and counterinsurgency on the occupied territories. The documents bring to light connections between the exarchate and German counterintelligence and reveal the nature of political police work with informants. They capture the political mood of population and prisoners of war. There is information on participants of partisan movement and underground resistance, on communication net between the patriarchal exarchate in the Baltic states and the German counterintelligence. Reports and dispatches of the clergy in the pay of the Nazis addressed to the Metropolitan Sergius (Voskresensky) contain detailed activity reports. Investigatory records contain important biographical information and personal data on the collaborators. Most of the documents, being classified, have never been published before.

The History of the Judahite Bench Tomb

2018 ◽  
Author(s):  
Matthew Suriano
Keyword(s):  
Iron Age ◽  
Hebrew Bible ◽  
Cultural Practices ◽  
Seventh Century ◽  
Mortuary Practices ◽  
Iron Age Ii ◽  
Gradual Development ◽  
History Of ◽  
The Dead ◽  
Insight Into

The history of the Judahite bench tomb provides important insight into the meaning of mortuary practices, and by extension, death in the Hebrew Bible. The bench tomb appeared in Judah during Iron Age II. Although it included certain burial features that appear earlier in the Middle and Late Bronze Ages, such as burial benches, and the use of caves for extramural burials, the Judahite bench tomb uniquely incorporated these features into a specific plan that emulated domestic structures and facilitated multigenerational burials. During the seventh century, and continuing into the sixth, the bench tombs become popular in Jerusalem. The history of this type of burial shows a gradual development of cultural practices that were meant to control death and contain the dead. It is possible to observe within these cultural practices the tomb as a means of constructing identity for both the dead and the living.

The Major Transitions in Evolution

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Full Range ◽  
Evolution Of Cooperation ◽  
Major Transitions ◽  
Insect Societies ◽  
Wide Range ◽  
Major Transition ◽  
Life Itself ◽  
History Of ◽  
Emergence Of Cooperation ◽  
Multicellular Organisms

Over the history of life there have been several major changes in the way genetic information is organized and transmitted from one generation to the next. These transitions include the origin of life itself, the first eukaryotic cells, reproduction by sexual means, the appearance of multicellular plants and animals, the emergence of cooperation and of animal societies, and the unique language ability of humans. This ambitious book provides the first unified discussion of the full range of these transitions. The authors highlight the similarities between different transitions--between the union of replicating molecules to form chromosomes and of cells to form multicellular organisms, for example--and show how understanding one transition sheds light on others. They trace a common theme throughout the history of evolution: after a major transition some entities lose the ability to replicate independently, becoming able to reproduce only as part of a larger whole. The authors investigate this pattern and why selection between entities at a lower level does not disrupt selection at more complex levels. Their explanation encompasses a compelling theory of the evolution of cooperation at all levels of complexity. Engagingly written and filled with numerous illustrations, this book can be read with enjoyment by anyone with an undergraduate training in biology. It is ideal for advanced discussion groups on evolution and includes accessible discussions of a wide range of topics, from molecular biology and linguistics to insect societies.

Sign in / Sign up

Export Citation Format

Share Document