scholarly journals Cells at the Edge: The Dentin–Bone Interface in Zebrafish Teeth

2021 ◽  
Vol 12 ◽  
Author(s):  
Joana T. Rosa ◽  
Paul Eckhard Witten ◽  
Ann Huysseune
Keyword(s):  
Calcium Binding ◽  
Evolutionary History ◽  
Cell Types ◽  
Tissue Type ◽  
Dentinal Tubule ◽  
Jaw Bone ◽  
Attachment Structures ◽  
Mineralized Tissues ◽  
History Of ◽  
Bona Fide

Bone-producing osteoblasts and dentin-producing odontoblasts are closely related cell types, a result from their shared evolutionary history in the ancient dermal skeleton. In mammals, the two cell types can be distinguished based on histological characters and the cells’ position in the pulp cavity or in the tripartite periodontal complex. Different from mammals, teleost fish feature a broad diversity in tooth attachment modes, ranging from fibrous attachment to firm ankylosis to the underlying bone. The connection between dentin and jaw bone is often mediated by a collar of mineralized tissue, a part of the dental unit that has been termed “bone of attachment”. Its nature (bone, dentin, or an intermediate tissue type) is still debated. Likewise, there is a debate about the nature of the cells secreting this tissue: osteoblasts, odontoblasts, or yet another (intermediate) type of scleroblast. Here, we use expression of the P/Q rich secretory calcium-binding phosphoprotein 5 (scpp5) to characterize the cells lining the so-called bone of attachment in the zebrafish dentition. scpp5 is expressed in late cytodifferentiation stage odontoblasts but not in the cells depositing the “bone of attachment”. nor in bona fide osteoblasts lining the supporting pharyngeal jaw bone. Together with the presence of the osteoblast marker Zns-5, and the absence of covering epithelium, this links the cells depositing the “bone of attachment” to osteoblasts rather than to odontoblasts. The presence of dentinal tubule-like cell extensions and the near absence of osteocytes, nevertheless distinguishes the “bone of attachment” from true bone. These results suggest that the “bone of attachment” in zebrafish has characters intermediate between bone and dentin, and, as a tissue, is better termed “dentinous bone”. In other teleosts, the tissue may adopt different properties. The data furthermore support the view that these two tissues are part of a continuum of mineralized tissues. Expression of scpp5 can be a valuable tool to investigate how differentiation pathways diverge between osteoblasts and odontoblasts in teleost models and help resolving the evolutionary history of tooth attachment structures in actinopterygians.

scholarly journals Mineralized Cartilage and Bone-Like Tissues in Chondrichthyans Offer Potential Insights Into the Evolution and Development of Mineralized Tissues in the Vertebrate Endoskeleton

2021 ◽  
Vol 12 ◽  
Author(s):  
Oghenevwogaga J. Atake ◽  
B. Frank Eames
Keyword(s):  
Cell Types ◽  
Phylogenetic Position ◽  
Molecular Features ◽  
Evolution And Development ◽  
Mineralized Tissues ◽  
History Of ◽  
Living Organisms ◽  
Calcified Tissues ◽  
Vertebrate Skeleton ◽  
Comparative Embryology

The impregnation of biominerals into the extracellular matrix of living organisms, a process termed biomineralization, gives rise to diverse mineralized (or calcified) tissues in vertebrates. Preservation of mineralized tissues in the fossil record has provided insights into the evolutionary history of vertebrates and their skeletons. However, current understanding of the vertebrate skeleton and of the processes underlying its formation is biased towards biomedical models such as the tetrapods mouse and chick. Chondrichthyans (sharks, skates, rays, and chimaeras) and osteichthyans are the only vertebrate groups with extant (living) representatives that have a mineralized skeleton, but the basal phylogenetic position of chondrichthyans could potentially offer unique insights into skeletal evolution. For example, bone is a vertebrate novelty, but the internal supporting skeleton (endoskeleton) of extant chondrichthyans is commonly described as lacking bone. The molecular and developmental basis for this assertion is yet to be tested. Subperichondral tissues in the endoskeleton of some chondrichthyans display mineralization patterns and histological and molecular features of bone, thereby challenging the notion that extant chondrichthyans lack endoskeletal bone. Additionally, the chondrichthyan endoskeleton demonstrates some unique features and others that are potentially homologous with other vertebrates, including a polygonal mineralization pattern, a trabecular mineralization pattern, and an unconstricted perichordal sheath. Because of the basal phylogenetic position of chondrichthyans among all other extant vertebrates with a mineralized skeleton, developmental and molecular studies of chondrichthyans are critical to flesh out the evolution of vertebrate skeletal tissues, but only a handful of such studies have been carried out to date. This review discusses morphological and molecular features of chondrichthyan endoskeletal tissues and cell types, ultimately emphasizing how comparative embryology and transcriptomics can reveal homology of mineralized skeletal tissues (and their cell types) between chondrichthyans and other vertebrates.

scholarly journals Extracellular Traps: An Ancient Weapon of Multiple Kingdoms

Biology ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 34 ◽  
Author(s):  
Ariane Neumann ◽  
Graham Brogden ◽  
Maren von Köckritz-Blickwede
Keyword(s):  
Immune Cells ◽  
Crucial Role ◽  
Evolutionary History ◽  
Relevant Literature ◽  
Cell Types ◽  
Innate Immune ◽  
Innate Immune Cells ◽  
Defence Mechanisms ◽  
Extracellular Traps ◽  
History Of

The discovery, in 2004, of extracellular traps released by neutrophils has extended our understanding of the mode of action of various innate immune cells. This fascinating discovery demonstrated the extracellular trapping and killing of various pathogens by neutrophils. During the last decade, evidence has accumulated showing that extracellular traps play a crucial role in the defence mechanisms of various cell types present in vertebrates, invertebrates, and plants. The aim of this review is to summarise the relevant literature on the evolutionary history of extracellular traps used as a weapon in various kingdoms of life.

scholarly journals Novel Group I Intron in the tRNALeu(UAA) Gene of a γ-Proteobacterium Isolated from a Deep Subsurface Environment

2002 ◽  
Vol 184 (5) ◽  
pp. 1481-1487 ◽  
Author(s):  
Alexey A. Vepritskiy ◽  
Inna A. Vitol ◽  
Sandra A. Nierzwicki-Bauer
Keyword(s):  
Evolutionary History ◽  
Group I Intron ◽  
Anticodon Loop ◽  
Deep Subsurface ◽  
Subsurface Environment ◽  
Canonical Base ◽  
Group I ◽  
History Of ◽  
Bona Fide ◽  
Deep Subsurface Environment

ABSTRACT A group I intron has been found to interrupt the anticodon loop of the tRNALeu(UAA) gene in a bacterium belonging to the γ-subdivision of Proteobacteria and isolated from a deep subsurface environment. The subsurface isolate SMCC D0715 was identified as belonging to the genus Pseudomonas. The group I intron from this isolate is the first to be reported for γ-proteobacteria, and the first instance of a tRNALeu(UAA) group I intron to be found in a group of bacteria other than cyanobacteria. The 231-nucleotide (nt) intron's sequence has group I conserved elements and folds into a bona fide group I secondary structure with canonical base-paired segments P1 to P9 and a paired region, P10. The D0715 intron possesses the 11-nt motif CCUACG … UAUGG in its P8 region, a feature not common in bacterial introns. To date, phylogenetic analysis has shown that bacterial introns form two distinct families, and their complex distribution suggests that both lateral transfer and common ancestry have taken part in the evolutionary history of these elements.

scholarly journals Insm1-expressing neurons and secretory cells develop from a common pool of progenitors in the sea anemone Nematostella vectensis

2021 ◽  
Author(s):  
Oceane Tourniere ◽  
Henriette Busengdal ◽  
James M Gahan ◽  
Fabian Rentzsch
Keyword(s):  
Evolutionary History ◽  
Endocrine Cells ◽  
Evolutionary Relationship ◽  
Cell Types ◽  
Sea Anemone ◽  
Nematostella Vectensis ◽  
Secretory Cells ◽  
Common Pool ◽  
History Of ◽  
Relationship Of

Neurons are highly specialized cells present in nearly all animals, but their evolutionary origin and relationship to other cell types is not well understood. We use here the sea anemone Nematostella vectensis as a model system for early-branching animals to gain fresh insights into the evolutionary history of neurons. We generated a transgenic reporter line to show that the transcription factor NvInsm1 is expressed in post-mitotic cells that give rise to various types of neurons and secretory cells. Expression analyses, double transgenics and gene knockdown experiments show that the NvInsm1-expressing neurons and secretory cells derive from a common pool of NvSoxB(2)-positive progenitor cells. These findings, together with the requirement for Insm1 for the development of neurons and endocrine cells in vertebrates, support a close evolutionary relationship of neurons and secretory cells.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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