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1
Clement, JG. "Re-examination of the fine structure of endoskeletal mineralization in Chondrichthyans: Implications for growth, ageing and calcium Homeostasis." Marine and Freshwater Research 43, no. 1 (1992): 157. http://dx.doi.org/10.1071/mf9920157.
Анотація:
This paper presents a review of the literature describing calcium regulation mechanisms of chondrichthyans, with particular emphasis being given to implications for the nature of the skeleton. A further review of the literature describing mineralized skeletal tissues explores the many conflicting claims about the presence or absence of bone in chondrichthyans. The fine structure of axial and appendicular mineralized tissues from five genera is then described, and evidence is presented to support or refute the hypotheses of others concerning the presence of bone, turnover in the skeleton, and growth without resorption.
2
Bengtson, Stefan. "Early skeletal fossils." Paleontological Society Papers 10 (November 2004): 67–78. http://dx.doi.org/10.1017/s1089332600002345.
Анотація:
The Precambrian-Cambrian transition saw the burgeoning of diverse skeletal organisms (“small shelly fossils”), represented in the fossil record by spicules, tubes, tests, conchs, shells, and a variety of sclerites and ossicles. Whereas calcareous biomineralization as such may have been facilitated by changes in ocean chemistry at this time, the utilization of biominerals in mineralized skeletons is a different process. The massive appearance of skeletons is most likely an epiphenomenon of the general radiation of body plans and tissues. The “choice” of biominerals (mainly calcium carbonates, calcium phosphates, and silica) may reflect the environmental conditions under which the particular skeleton first evolved.
3
Dean, Mason N., and Adam P. Summers. "Mineralized cartilage in the skeleton of chondrichthyan fishes." Zoology 109, no. 2 (May 2006): 164–68. http://dx.doi.org/10.1016/j.zool.2006.03.002.
4
Keating, Joseph N., and Philip C. J. Donoghue. "Histology and affinity of anaspids, and the early evolution of the vertebrate dermal skeleton." Proceedings of the Royal Society B: Biological Sciences 283, no. 1826 (March 16, 2016): 20152917. http://dx.doi.org/10.1098/rspb.2015.2917.
Анотація:
The assembly of the gnathostome bodyplan constitutes a formative episode in vertebrate evolutionary history, an interval in which the mineralized skeleton and its canonical suite of cell and tissue types originated. Fossil jawless fishes, assigned to the gnathostome stem-lineage, provide an unparalleled insight into the origin and evolution of the skeleton, hindered only by uncertainty over the phylogenetic position and evolutionary significance of key clades. Chief among these are the jawless anaspids, whose skeletal composition, a rich source of phylogenetic information, is poorly characterized. Here we survey the histology of representatives spanning anaspid diversity and infer their generalized skeletal architecture. The anaspid dermal skeleton is composed of odontodes comprising spheritic dentine and enameloid, overlying a basal layer of acellular parallel fibre bone containing an extensive shallow canal network. A recoded and revised phylogenetic analysis using equal and implied weights parsimony resolves anaspids as monophyletic, nested among stem-gnathostomes. Our results suggest the anaspid dermal skeleton is a degenerate derivative of a histologically more complex ancestral vertebrate skeleton, rather than reflecting primitive simplicity. Hypotheses that anaspids are ancestral skeletonizing lampreys, or a derived lineage of jawless vertebrates with paired fins, are rejected.
5
Schober, H. C., Z. H. Han, A. J. Foldes, M. S. Shih, D. S. Rao, R. Balena, and A. M. Parfitt. "Mineralized bone loss at different sites in dialysis patients: implications for prevention." Journal of the American Society of Nephrology 9, no. 7 (July 1998): 1225–33. http://dx.doi.org/10.1681/asn.v971225.
Анотація:
To characterize the magnitude and location of mineralized bone loss, 40 patients (20 men, 20 women, 29 white, 11 black) with clinically significant renal osteodystrophy who could be unambiguously classified based on histologic criteria as having osteitis fibrosa (OF; 20 cases) or osteomalacia (OM; 20 cases) were studied; they had been on maintenance hemodialysis for 4.6 +/- 3.0 yr. One hundred forty-two healthy women of similar age and ethnic composition served as control subjects. In all subjects, the proportions of mineralized bone, osteoid, and porosity (nonbone soft tissue) were measured separately in cortical and cancellous bone tissue, from intact full-thickness biopsies of the ilium, representative of the axial skeleton. The results were related to the volumes of cortical and cancellous bone tissue separately and to the volume of the entire biopsy core. Approximately three-quarters of the patients had measurements in the appendicular skeleton by single photon absorptiometry of the radius and morphometry of the metacarpal. Disease effects did not differ significantly between ethnic groups. Mineralized cortical bone volume (per unit of core volume) was reduced by approximately 45% in both patient groups. Mineralized cancellous bone volume was significantly increased by 36% in the patients with OF and nonsignificantly reduced by 9% in the patients with OM; however, the reduction in the latter patients was significant in relation to tissue volume. The combined total deficit for both types of iliac bone was approximately 20% in the patients with OF and approximately 40% in the patients with OM. Significant reductions in appendicular cortical bone were demonstrated in both patient groups at both measurement sites. Regardless of the current histologic classification, the major structural abnormality in the skeleton is generalized thinning of cortical bone due to increased net endocortical resorption, the most characteristic effect on bone of hyperparathyroidism. Protection of the skeleton from the adverse consequences of renal failure will require therapeutic intervention in patients with no symptoms of either renal or bone disease.
6
Kröger, Björn, Olev Vinn, Ursula Toom, Ian J. Corfe, Jukka Kuva, and Michał Zatoń. "On the enigma of Palaenigma wrangeli (Schmidt), a conulariid with a partly non-mineralized skeleton." PeerJ 9 (November 2, 2021): e12374. http://dx.doi.org/10.7717/peerj.12374.
Анотація:
Palaenigma wrangeli (Schmidt) is a finger-sized fossil with a tetraradiate conical skeleton; it occurs as a rare component in fossiliferous Upper Ordovician strata of the eastern Baltic Basin and is known exclusively from north Estonia. The systematic affinities and palaeoecology of P. wrangeli remained questionable. Here, the available specimens of P. wrangeli have been reexamined using scanning electron microscopy and x-ray computed tomography (microCT). Additionally, the elemental composition of the skeletal elements has been checked using energy dispersive X-ray spectroscopy. The resulting 2D-, and 3D-scans reveal that P. wrangeli consists of an alternation of distinct calcium phosphate (apatite) lamellae and originally organic-rich inter-layers. The lamellae form four semicircular marginal pillars, which are connected by irregularly spaced transverse diaphragms. Marginally, the diaphragms and pillar lamellae are not connected to each other and thus do not form a closed periderm structure. A non-mineralized or poorly mineralized external periderm existed originally in P. wrangeli but is only rarely and fragmentary preserved. P. wrangeli often co-occurs with conulariids in fossil-rich limestone with mudstone–wackestone lithologies. Based on the new data, P. wrangeli can be best interpreted as a poorly mineralized conulariinid from an original soft bottom habitat. Here the new conulariinid family Palaenigmaidae fam. nov. is proposed as the monotypic taxon for P. wrangeli.
7
GUINOT, GUILLAUME, SYLVAIN ADNET, KENSHU SHIMADA, KENSHU SHIMADA, CHARLIE J. UNDERWOOD, MIKAEL SIVERSSON, DAVID J. WARD, JÜRGEN KRIWET, and HENRI CAPPETTA. "On the need of providing tooth morphology in descriptions of extant elasmobranch species." Zootaxa 4461, no. 1 (August 20, 2018): 118. http://dx.doi.org/10.11646/zootaxa.4461.1.8.
Анотація:
Elasmobranchii is a clade of chondrichthyans (cartilaginous fishes) that comprises sharks, skates and rays represented today by approximately 1,200 species. Chondrichthyans have a long evolutionary history dating back to the Late Ordovician (ca. 450 million years ago [Mya]) based on isolated dermal denticles (Janvier 1996). Other remains such as articulated skeletons and teeth are known from the Lower Devonian (ca. 410 Mya: Mader 1986; Miller et al. 2003). The fossil record of modern elasmobranchs (Neoselachii) can be traced back to the Early Permian (ca. 290 Mya) and is represented by isolated teeth (Ivanov 2005), with fossils of crown group sharks and rays appearing in Lower Jurassic (ca. 200 Mya) rocks (e.g., Cappetta 2012). Since their appearance in the geological record, elasmobranchs are mainly represented by isolated teeth, whereas articulated skeletons are very rare and restricted to a small number of fossil localities (e.g., Cappetta 2012). The scarcity of skeletal remains in their fossil record is due to their poorly mineralized cartilaginous skeleton that requires special taphonomical conditions to be preserved. Elasmobranch teeth, in contrast, are composed of highly mineralized tissues (hydroxyapatite) that have a strong preservation potential (Shimada 2006). In addition, elasmobranchs replace their teeth continuously over the course of their life span (polyphyodonty) and therefore shed thousands of teeth in their lifetime (Reif et al. 1978; Schnetz et al. 2016) leading to large numbers of potential fossils. These morphologically highly diverse isolated teeth constitute much of the rich fossil record of elasmobranchs, and largely form the basis of our understanding of elasmobranch diversity and evolution through geological time.
8
Liu, Kun, Chun-Xiu Meng, Zhao-Yong Lv, Yu-Jue Zhang, Jun Li, Ke-Yi Li, Feng-Zhen Liu, Bin Zhang, and Fu-Zhai Cui. "Enhancement of BMP-2 and VEGF carried by mineralized collagen for mandibular bone regeneration." Regenerative Biomaterials 7, no. 4 (June 13, 2020): 435–40. http://dx.doi.org/10.1093/rb/rbaa022.
Анотація:
Abstract Repairing damage in the craniofacial skeleton is challenging. Craniofacial bones require intramembranous ossification to generate tissue-engineered bone grafts via angiogenesis and osteogenesis. Here, we designed a mineralized collagen delivery system for BMP-2 and vascular endothelial growth factor (VEGF) for implantation into animal models of mandibular defects. BMP-2/VEGF were mixed with mineralized collagen which was implanted into the rabbit mandibular. Animals were divided into (i) controls with no growth factors; (ii) BMP-2 alone; or (iii) BMP-2 and VEGF combined. CT and hisomputed tomography and histological staining were performed to assess bone repair. New bone formation was higher in BMP-2 and BMP-2-VEGF groups in which angiogenesis and osteogenesis were enhanced. This highlights the use of mineralized collagen with BMP-2/VEGF as an effective alternative for bone regeneration.
9
Barattolo, Filippo, Ioan I. Bucur, and Alexandru V. Marian. "Deciphering voids in Dasycladales, the case of Dragastanella transylvanica, a new Lower Cretaceous triploporellacean genus and species from Romania." Journal of Paleontology 95, no. 5 (May 27, 2021): 889–905. http://dx.doi.org/10.1017/jpa.2021.40.
Анотація:
AbstractDragastanella transylvanica n. gen. n. sp. is described. Its calcified skeleton contains numerous voids, partly related to the molds of soft parts of the alga, but also related to lack of calcification. Interpretation of these voids, especially their attribution to original structures (e.g., primary lateral versus reproductive organ), has important implications for the taxonomic position of the alga, even at the family level. Examination of key sections that include the boundary between sterile and fertile parts of the alga excludes the occurrence of external reproductive organs. Unusual, paired pores in the outer part of the mineralized skeleton reflect an asymmetry within the whorl, excluding the presence of secondary laterals. The alga is characterized by a cylindrical to club-shaped thallus bearing only phloiophorous primary laterals arranged in whorls and flaring outwards, forming a cortex. Mineralized lenticular reproductive organs containing cysts set in the equatorial plane (Russoella-type gametophores) occur inside primary laterals (cladosporous arrangement of the reproductive organs). These characters support establishment of the new genus Dragastanella. Dragastanella transylvanica n. gen. n. sp. resembles species previously referred to Zittelina (Zittelina hispanica and Zittelina massei) and Triploporella (Triploporella matesina and Triploporella carpatica). Except for Triploporella carpatica, whose mineralized skeleton does not permit confident attribution to either Triploporella or Dragastanella n. gen., the other species must be ascribed to Dragastanella n. gen. Therefore, the following new combinations are proposed: Dragastanella hispanica n. comb., Dragastanella massei n. comb., and Dragastanella matesina n. comb. Despite widely overlapping biometrical measurements, these species can be differentiated by the size and location of their reproductive organs, the pattern of calcification around the primary laterals, and relationships among structural parameters such as the size of laterals, number of laterals per whorl, and distance between whorls.
10
Seidel, Ronald, Michael Blumer, Júlia Chaumel, Shahrouz Amini, and Mason N. Dean. "Endoskeletal mineralization in chimaera and a comparative guide to tessellated cartilage in chondrichthyan fishes (sharks, rays and chimaera)." Journal of The Royal Society Interface 17, no. 171 (October 2020): 20200474. http://dx.doi.org/10.1098/rsif.2020.0474.
Анотація:
An accepted uniting character of modern cartilaginous fishes (sharks, rays, chimaera) is the presence of a mineralized, skeletal crust, tiled by numerous minute plates called tesserae. Tesserae have, however, never been demonstrated in modern chimaera and it is debated whether the skeleton mineralizes at all. We show for the first time that tessellated cartilage was not lost in chimaera, as has been previously postulated, and is in many ways similar to that of sharks and rays. Tesserae in Chimaera monstrosa are less regular in shape and size in comparison to the general scheme of polygonal tesserae in sharks and rays, yet share several features with them. For example, Chimaera tesserae, like those of elasmobranchs, possess both intertesseral joints (unmineralized regions, where fibrous tissue links adjacent tesserae) and recurring patterns of local mineral density variation (e.g. Liesegang lines, hypermineralized ‘spokes’), reflecting periodic accretion of mineral at tesseral edges as tesserae grow. Chimaera monstrosa 's tesserae, however, appear to lack the internal cell networks that characterize tesserae in elasmobranchs, indicating fundamental differences among chondrichthyan groups in how calcification is controlled. By compiling and comparing recent ultrastructure data on tesserae, we also provide a synthesized, up-to-date and comparative glossary on tessellated cartilage, as well as a perspective on the current state of research into the topic, offering benchmark context for future research into modern and extinct vertebrate skeletal tissues.
11
Probian, Christina, Annika Wülfing, and Jens Harder. "Anaerobic Mineralization of Quaternary Carbon Atoms: Isolation of Denitrifying Bacteria on Pivalic Acid (2,2-Dimethylpropionic Acid)." Applied and Environmental Microbiology 69, no. 3 (March 2003): 1866–70. http://dx.doi.org/10.1128/aem.69.3.1866-1870.2003.
Анотація:
ABSTRACT The degradability of pivalic acid was established by the isolation of several facultative denitrifying strains belonging to Zoogloea resiniphila, to Thauera and Herbaspirillum, and to Comamonadaceae, related to [Aquaspirillum] and Acidovorax, and of a nitrate-reducing bacterium affiliated with Moraxella osloensis. Pivalic acid was completely mineralized to carbon dioxide. The catabolic pathways may involve an oxidation to dimethylmalonate or a carbon skeleton rearrangement, a putative 2,2-dimethylpropionyl coenzyme A mutase.
12
Clement, JG, RA Officer, and E. Dykes. "Three-dimensional reconstruction of Shark Vertebrae: A technique with applications to age and growth studies." Marine and Freshwater Research 43, no. 5 (1992): 923. http://dx.doi.org/10.1071/mf9920923.
Анотація:
Shark vertebral centra show no histological evidence of resorption at any time in the animals' life. Deorganification of centra always reveals a large, residual, stable, three-dimensional skeleton. In contrast, the mineralized parts of other organs (e.g. claspers and jaws) crumble into their individual mineralized subunits, the tesserae, upon deorganification. In both cases, only appositional growth of cartilage on the pre-existing mineralized template is possible. The basic 'double-cone' shape of the vertebrae facilitates increases in body length simultaneously with an accompanying increase in girth. Once the initial shape of the mineralized portion of a vertebral centrum is fully established and hence can be described, then relatively simple mathematical models might be devised to predict future growth patterns. To advance this hypothesis, it has first been necessary to develop a method that can accurately record the sizes and shapes of complex three-dimensional anatomical structures. This paper describes a technique that is capable not only of recording and measuring the size and shape of shark vertebrae but also of predicting their subsequent growth. Furthermore, the technique enables reproduction of three-dimensional coloured and shaded stereoscopic images of vertebral structures, facilitating a better understanding of their intricate morphology. Three-dimensional coordinate data gathered from any shark vertebra can be manipulated mathematically to model future vertebral growth. Producing realistic images of vertebrae transformed in this way may allow the exploration of possibly unrealized taxonomic affinities.
13
Khavandgar, Zohreh, Christophe Poirier, Christopher J. Clarke, Jingjing Li, Nicholas Wang, Marc D. McKee, Yusuf A. Hannun, and Monzur Murshed. "A cell-autonomous requirement for neutral sphingomyelinase 2 in bone mineralization." Journal of Cell Biology 194, no. 2 (July 25, 2011): 277–89. http://dx.doi.org/10.1083/jcb.201102051.
Анотація:
A deletion mutation called fro (fragilitas ossium) in the murine Smpd3 (sphingomyelin phosphodiesterase 3) gene leads to a severe skeletal dysplasia. Smpd3 encodes a neutral sphingomyelinase (nSMase2), which cleaves sphingomyelin to generate bioactive lipid metabolites. We examined endochondral ossification in embryonic day 15.5 fro/fro mouse embryos and observed impaired apoptosis of hypertrophic chondrocytes and severely undermineralized cortical bones in the developing skeleton. In a recent study, it was suggested that nSMase2 activity in the brain regulates skeletal development through endocrine factors. However, we detected Smpd3 expression in both embryonic and postnatal skeletal tissues in wild-type mice. To investigate whether nSMase2 plays a cell-autonomous role in these tissues, we examined the in vitro mineralization properties of fro/fro osteoblast cultures. fro/fro cultures mineralized less than the control osteoblast cultures. We next generated fro/fro;Col1a1-Smpd3 mice, in which osteoblast-specific expression of Smpd3 corrected the bone abnormalities observed in fro/fro embryos without affecting the cartilage phenotype. Our data suggest tissue-specific roles for nSMase2 in skeletal tissues.
14
Kaskova, L. F., L. F. Chuprina, N. A. Morgun, O. Yu Andriyanova, and A. V. Artemiev. "DENTAL STATUS OF BRONZE AGE POPULATION FROM THE AREA OF MODERN POLTAVA REGION (ACCORDING TO THE ANTHROPOLOGICAL MATERIALS)." Ukrainian Dental Almanac, no. 3 (September 30, 2022): 5–8. http://dx.doi.org/10.31718/2409-0255.3.2022.01.
Анотація:
In modern medical science, and in particular in dentistry, regarding pathology, the following question is actual invariably: Have there always been manifestations of diseases as we see them today? At the same time, research on dental diseases in ancient people remains also a reliable source of knowledge about the causes of oral cavity pathology in the modern population.
Therefore, it is important to study deviations from the norms of development and peculiarities of skeleton of populations in various periods.
The purpose of the study. To investigate the condition of hard oral tissues in the Bronze Age population from the area of modern Poltava region by skeletal remains.
Object and methods of research. For the analysis the bone remains of 47 representatives (4 children's, 20 women's and 23 men's skeletons) of population of the Bronze Age (middle of the 3rd millennium – the 2nd millennium BC), from the area of modern Poltava region (main group), from the mound located in the vicinity of the village Hittsi of the Lubenskyi district, discovered by the archeological expedition in 2021 were selected.
Anthropological series of individuals living in the Bronze Age on the territory of modern Poltava region described earlier were taken as a control group for comparison.
The materials were discovered during the archaeological excavations carried out in 1998-2012, where a total of 102 skeletons were examined (30 children's skeletons, women's skeletons among examined are 20, and male ones are 52.)
The study of the material was carried out by the method of skeletal tissue analysis of ancient people, developed by the authors of this publication on the basis of the Laboratory of Medical and Historical Anthropology of the Municipal Establishment "Center of Protection and Research of Archaeological Monuments" of Poltava Regional Council and the Children's Department of Therapeutic Dentistry with prevention of dental diseases of Poltava State Medical University. The method provides maximum preservation of bone and teeth tissues.
Research results. Differences in the dental status of the main group correspond to the results of the paleopathological analysis of the collective anthropological series of the Bronze Age control group from the area of Poltava region (where there were found 4 tooth cavities per 102 persons and in another 22 persons dental mineralized deposits were observed) which reflect a specific consequence of the negative impact of social factors and environment in places of residence. However, the difference was determined in the form of coverage of the chewing organs with teeth mineralized deposits. Discrepancy in the number of encounters of mineralized deposits in the teeth of the studied groups is probably explained by the difference in food consumption and possible differences in types of lifestyles, the possible tendency of the male population to long transitions.
Conclusion. The general somatic status of the control group of the studied people corresponds to the state of health of the Bronze Age population of the main group from the area of Poltava.
So, another 47 people of the Bronze Age showed the same dynamics of the development of dental pathology with previously studied skeletons of representatives of this time from the area of the modern Poltava region.
15
Rücklin, Martin, Philip C. J. Donoghue, John A. Cunningham, Federica Marone, and Marco Stampanoni. "Developmental paleobiology of the vertebrate skeleton." Journal of Paleontology 88, no. 4 (July 2014): 676–83. http://dx.doi.org/10.1666/13-107.
Анотація:
Studies of the development of organisms can reveal crucial information on homology of structures. Developmental data are not peculiar to living organisms, and they are routinely preserved in the mineralized tissues that comprise the vertebrate skeleton, allowing us to obtain direct insight into the developmental evolution of this most formative of vertebrate innovations. The pattern of developmental processes is recorded in fossils as successive stages inferred from the gross morphology of multiple specimens and, more reliably and routinely, through the ontogenetic stages of development seen in the skeletal histology of individuals. Traditional techniques are destructive and restricted to a 2-D plane with the third dimension inferred. Effective non-invasive methods of visualizing paleohistology to reconstruct developmental stages of the skeleton are necessary.In a brief survey of paleohistological techniques we discuss the pros and cons of these methods. The use of tomographic methods to reconstruct development of organs is exemplified by the study of the placoderm dentition. Testing evidence for the presence of teeth in placoderms, the first jawed vertebrates, we compare the methods that have been used. These include inferring development from morphology, and using serial sectioning, microCT or synchrotron X-ray tomographic microscopy (SRXTM), to reconstruct growth stages and directions of growth. The ensuing developmental interpretations are biased by the methods and degree of inference. The most direct and reliable method is using SRXTM data to trace sclerochronology. The resulting developmental data can be used to resolve homology and test hypotheses on the origin of evolutionary novelties.
16
Bandel, Klaus. "Cephalopod Morphology and Function." Notes for a Short Course: Studies in Geology 13 (1985): 190–201. http://dx.doi.org/10.1017/s0271164800001172.
Анотація:
General Organization of Recent Cephalopods. Extant cephalopods with the exception of Nautilus have an internal shell covered by muscular mantle. Only Nautilus is able to withdraw into its shell and close the aperture with a hood. The internal shells of Sepia and Spirula are mineralized and have chambers that function in buoyancy control (Denton & Gilpin-Brown, 1961, 1971; Denton et al., 1961, 1967) while other teuthids and Vampyroteuthis have an unmineralized internal skeleton that acts as an elastic support to the soft body.
17
Rolvien, Tim, Florian Nagel, Petar Milovanovic, Sven Wuertz, Robert Percy Marshall, Anke Jeschke, Felix N. Schmidt, et al. "How the European eel ( Anguilla anguilla ) loses its skeletal framework across lifetime." Proceedings of the Royal Society B: Biological Sciences 283, no. 1841 (October 26, 2016): 20161550. http://dx.doi.org/10.1098/rspb.2016.1550.
Анотація:
European eels ( Anguilla anguilla ) undertake an impressive 5 000 km long migration from European fresh waters through the North Atlantic Ocean to the Sargasso Sea. Along with sexual maturation, the eel skeleton undergoes a remarkable morphological transformation during migration, where a hitherto completely obscure bone loss phenomenon occurs. To unravel mechanisms of the maturation-related decay of the skeleton, we performed a multiscale assessment of eels' bones at different life-cycle stages. Accordingly, the skeleton reflects extensive bone loss that is mediated via multinucleated bone-resorbing osteoclasts, while other resorption mechanisms such as osteocytic osteolysis or matrix demineralization were not observed. Preserving mechanical stability and releasing minerals for energy metabolism are two mutually exclusive functions of the skeleton that are orchestrated in eels through the presence of two spatially segregated hard tissues: cellular bone and acellular notochord. The cellular bone serves as a source of mineral release following osteoclastic resorption, whereas the mineralized notochord sheath, which is inaccessible for resorption processes due to an unmineralized cover layer, ensures sufficient mechanical stability as a part of the notochord sheath. Clearly, an eel's skeleton is structurally optimized to meet the metabolic challenge of fasting and simultaneous sexual development during an exhausting journey to spawning areas, while the function of the vertebral column is maintained to achieve this goal.
18
Yue, Zhao, Stefan Bengtson, and Stephen W. F. Grant. "Biology and functional morphology of Cloudina, the earliest known metazoan with a mineralized skeleton." Paleontological Society Special Publications 6 (1992): 325. http://dx.doi.org/10.1017/s2475262200008856.
Анотація:
The earliest known skeletal metazoan, Cloudina, was widespread in the late Neoproterozoic. We report here on phosphatized specimens of Cloudina sp. from dolomites of the Dengying Formation, 30 m below the first Cambrian skeletal fauna, in the Lijiagou section, Shaanxi Province, China. The specimens exhibit new details of shell morphology and fine structure that offer insights concerning the mechanism of shell accretion and the selective pressures influencing skeletogenesis in metazaons.Cloudina formed curved to sinous tubular shells 0.2-8 mm in diameter and up to 4 cm in length. They consist of numerous thin (5-10 μm) calcareous layers, each in the form of a slightly flaring tube. New layers were deposited above and to one side of the previous layer, giving rise to a series of eccentrically nested shell laminae. Some of the phosphatized layers exhibit tight folding or wrinkling that may have been primary (imparting additional strength) or secondary (related to plastic deformation of organic-rich shell material). Pore space existed between terminal thin flanges, but concentric ridges may have served to strengthen the free standing portions of shell layers. SEM and cathodoluminescence of polished thin sections also reveal that each shell layer may itself have been constructed of an organized layering of organic matrix and carbonate, suggesting a fairly sophisticated biologic control over shell formation. The presence of circular holes, the size of which correlates positively with tube diameter, moreover, strongly suggests that one function of the shell was to protect the Cloudina organism from predatorial and/or parasitic attack.The taxonomic status of Cloudina remains problematic. Rare specimens of the Lijiagou Cloudina which show two younger tubes growing within an older single tube suggest that the organism was capable of asexual reproduction by longitudinal fission. Such a latent tendency is not compatible with previously proposed affinities with polychaete worms.
19
Wei, Fan, Yang Zhao, Ailin Chen, Xianguang Hou, and Peiyun Cong. "New vauxiid sponges from the Chengjiang Biota and their evolutionary significance." Journal of the Geological Society 178, no. 5 (March 22, 2021): jgs2020–162. http://dx.doi.org/10.1144/jgs2020-162.
Анотація:
Aspiculate demosponges are rarely described in geological history due to the absence of spicules that are stable and resistant to degradation. One exception is the exquisite preservation of sponges without any mineralized skeletons discovered in Lagerstätten (e.g. the Burgess Shale). The Chengjiang Biota, an early example of a Burgess Shale-type biota in South China (Cambrian Series 2, Stage 3), is one of the only examples of convincing aspiculate sponges until now. Here, we describe Vauxia pregracilenta sp. nov. and V. paraleioia sp. nov., as well as two poorly preserved vauxiid specimens (Vauxia sp.) in open nomenclature, from the Chengjiang Biota. Vauxia pregracilenta has a fan-like holdfast and branches in various sizes, as well as a typical two-layered net-like skeleton, without spicules. The endosomal layer is hexagonal, while the dermal layer is sub-rectangular. Vauxia paraleioia is characterized by a two-layered subconical skeleton, with the dermal layer ornamented with vertical surface grooves. The openings of the dermal and endosomal layers of V. paraleioia are both hexagonal but of different sizes. These newly discovered Vauxia species indicate that the aspiculate sponges were diversified in the early Cambrian. Partial silicification of the fibres of aspiculate Vauxia are confirmed from the Chengjiang Biota.Thematic collection: This article is part of the Advances in the Cambrian Explosion collection available at: https://www.lyellcollection.org/cc/advances-cambrian-explosion
20
Vázquez, José Antonio, Javier Fraguas, Pío González, Julia Serra, and Jesus Valcarcel. "Optimal Recovery of Valuable Biomaterials, Chondroitin Sulfate and Bioapatites, from Central Skeleton Wastes of Blue Shark." Polymers 12, no. 11 (November 6, 2020): 2613. http://dx.doi.org/10.3390/polym12112613.
Анотація:
The industrial filleting of blue shark (Prionace glauca) led to the generation of a large number of central skeletons of low interest to fishmeal plants handling such wastes. In this context, the present study describes the optimization of the hydrolysis process (pH 8.35, T 58 °C, 1% (v/w) of alcalase and t = 4 h) to produce chondroitin sulfate (CS) together with the recovery of bioapatites. Then, that hydrolysate was chemically treated with an optimal alkaline-hydroalcoholic-saline solution (0.48 M of NaOH, 1.07 volumes of EtOH and 2.5 g/L of NaCl) and finally purified by ultrafiltration-diafiltration (30 kDa) to obtain glycosaminoglycan with a purity of 97% and a productive yield of 2.8% (w/w of skeleton). The size of the biopolymer (CS) was of 58 kDa with prevalence of 6S-GalNAc sulfation (4S/6S ratio of 0.25), 12% of GlcA 2S-GalNAc 6S and 6% of non-sulfated disaccharides. Crude bioapatites were purified by pyrolysis and FT-Raman and XRD techniques confirm the presence of hydroxyapatite [Ca5(PO4)3(OH)], with a molar mass of 502.3 g/mol, embedded in the organic matrix of the skeleton. The mineralized tissues of blue shark are promising marine sources for the extraction of high value biomaterials with clinical application in bone and tissue regeneration and are still completely unexplored.
21
BLAIR, Harry C., Mone ZAIDI, and Paul H. SCHLESINGER. "Mechanisms balancing skeletal matrix synthesis and degradation." Biochemical Journal 364, no. 2 (June 1, 2002): 329–41. http://dx.doi.org/10.1042/bj20020165.
Анотація:
Bone is regulated by evolutionarily conserved signals that balance continuous differentiation of bone matrix-producing cells against apoptosis and matrix removal. This is continued from embryogenesis, where the skeleton differentiates as a solid mass and is shaped into separate bones by cell death and proteolysis. The two major tissues of the skeleton are avascular cartilage, with an extracellular matrix based on type II collagen and hydrophilic proteoglycans, and bone, a stronger and lighter material based on oriented type I collagen and hydroxyapatite. Both differentiate from the same mesenchymal stem cells. This differentiation is regulated by a family of related signals centred on bone morphogenic proteins. Fibroblast growth factors, Indian hedgehog and parathyroid hormone-related protein are important in determining the type of matrix and the relation of skeletal and non-skeletal structures. Removal of mineralized matrix involves apoptosis of matrix cells and differentiation of acid-secreting cells (osteoclasts) from macrophage precursors. Key regulators of matrix removal are signals in the tumour-necrosis-factor family. Osteoclasts dissolve bone by isolating a region of the matrix and secreting HCl and proteinases at that site. Successive cycles of removal and replacement allow growth, repair and remodelling. The signals for bone turnover are predominantly cell-membrane-associated, allowing very specific spatial regulation. In addition to its support function, bone is a reservoir of Ca2+, PO3-4 and OH−. Secondary modulation of mineral secretion and bone degradation are mediated by humoral signals, including parathyroid hormone and vitamin D, as well as the cytokines that also regulate the underlying cell differentiation.
22
Gilbert, Pupa U. P. A., Susannah M. Porter, Chang-Yu Sun, Shuhai Xiao, Brandt M. Gibson, Noa Shenkar, and Andrew H. Knoll. "Biomineralization by particle attachment in early animals." Proceedings of the National Academy of Sciences 116, no. 36 (August 19, 2019): 17659–65. http://dx.doi.org/10.1073/pnas.1902273116.
Анотація:
Crystallization by particle attachment (CPA) of amorphous precursors has been demonstrated in modern biomineralized skeletons across a broad phylogenetic range of animals. Precisely the same precursors, hydrated (ACC-H2O) and anhydrous calcium carbonate (ACC), have been observed spectromicroscopically in echinoderms, mollusks, and cnidarians, phyla drawn from the 3 major clades of eumetazoans. Scanning electron microscopy (SEM) here also shows evidence of CPA in tunicate chordates. This is surprising, as species in these clades have no common ancestor that formed a mineralized skeleton and appear to have evolved carbonate biomineralization independently millions of years after their late Neoproterozoic divergence. Here we correlate the occurrence of CPA from ACC precursor particles with nanoparticulate fabric and then use the latter to investigate the antiquity of the former. SEM images of early biominerals from Ediacaran and Cambrian shelly fossils show that these early calcifiers used attachment of ACC particles to form their biominerals. The convergent evolution of biomineral CPA may have been dictated by the same thermodynamics and kinetics as we observe today.
23
Dean, Mason N., Joseph J. Bizzarro, Brett Clark, Charlie J. Underwood, and Zerina Johanson. "Large batoid fishes frequently consume stingrays despite skeletal damage." Royal Society Open Science 4, no. 9 (September 2017): 170674. http://dx.doi.org/10.1098/rsos.170674.
Анотація:
The shapes of vertebrate teeth are often used as hallmarks of diet. Here, however, we demonstrate evidence of frequent piscivory by cartilaginous fishes with pebble-like teeth that are typically associated with durophagy, the eating of hard-shelled prey. High-resolution micro-computed tomography observation of a jaw specimen from one batoid species and visual investigation of those of two additional species reveal large numbers of embedded stingray spines, arguing that stingray predation of a scale rivalling that of the largest carnivorous sharks may not be uncommon for large, predatory batoids with rounded, non-cutting dentition. Our observations demonstrate that tooth morphology is not always a reliable indicator of diet and that stingray spines are not as potent a deterrent to predation as normally believed. In addition, we show that several spines in close contact with the jaw skeleton of a wedgefish ( Rhynchobatus ) have become encased in a disorganized mineralized tissue with a distinctive ultrastructure, the first natural and unequivocal evidence of a callus-building response in the tessellated cartilage unique to elasmobranch skeletons. Our findings reveal sampling and analysis biases in vertebrate ecology, especially with regard to the role of large, predatory species, while also illustrating that large body size may provide an escape from anatomical constraints on diet (e.g. gape size, specialist dentition). Our observations inform our concepts of skeletal biology and evolution in showing that tessellated cartilage—an ancient alternative to bone—is incapable of foreign tissue resorption or of restoring damaged skeletal tissue to its original state, and attest to the value of museum and skeletal specimens as records of important aspects of animal life history.
24
Maridas, David E., Victoria E. DeMambro, Phuong T. Le, Kenichi Nagano, Roland Baron, Subburaman Mohan, and Clifford J. Rosen. "IGFBP-4 regulates adult skeletal growth in a sex-specific manner." Journal of Endocrinology 233, no. 1 (April 2017): 131–44. http://dx.doi.org/10.1530/joe-16-0673.
Анотація:
Insulin-like growth factor-1 (IGF-1) and its binding proteins are critical mediators of skeletal growth. Insulin-like growth factor-binding protein 4 (IGFBP-4) is highly expressed in osteoblasts and inhibits IGF-1 actions in vitro. Yet, in vivo studies suggest that it could potentiate IGF-1 and IGF-2 actions. In this study, we hypothesized that IGFBP-4 might potentiate the actions of IGF-1 on the skeleton. To test this, we comprehensively studied 8- and 16-week-old Igfbp4−/− mice. Both male and female adult Igfbp4−/− mice had marked growth retardation with reductions in body weight, body and femur lengths, fat proportion and lean mass at 8 and 16 weeks. Marked reductions in aBMD and aBMC were observed in 16-week-old Igfbp4−/− females, but not in males. Femoral trabecular BV/TV and thickness, cortical fraction and thickness in 16-week-old Igfbp4−/− females were significantly reduced. However, surprisingly, males had significantly more trabeculae with higher connectivity density than controls. Concordantly, histomorphometry revealed higher bone resorption and lower bone formation in Igfbp4−/− females. In contrast, Igfbp4−/− males had lower mineralized surface/bone surface. Femoral expression of Sost and circulating levels of sclerostin were reduced but only in Igfbp4−/− males. Bone marrow stromal cultures from mutants showed increased osteogenesis, whereas osteoclastogenesis was markedly increased in cells from Igfbp4−/− females but decreased in males. In sum, our results indicate that loss of Igfbp4 affects mesenchymal stromal cell differentiation, regulates osteoclastogenesis and influences both skeletal development and adult bone maintenance. Thus, IGFBP-4 modulates the skeleton in a gender-specific manner, acting as both a cell autonomous and cell non-autonomous factor.
25
Di Santo, Valentina. "Ocean acidification and warming affect skeletal mineralization in a marine fish." Proceedings of the Royal Society B: Biological Sciences 286, no. 1894 (January 9, 2019): 20182187. http://dx.doi.org/10.1098/rspb.2018.2187.
Анотація:
Ocean acidification and warming are known to alter, and in many cases decrease, calcification rates of shell and reef building marine invertebrates. However, to date, there are no datasets on the combined effect of ocean pH and temperature on skeletal mineralization of marine vertebrates, such as fishes. Here, the embryos of an oviparous marine fish, the little skate ( Leucoraja erinacea ), were developmentally acclimatized to current and increased temperature and CO 2 conditions as expected by the year 2100 (15 and 20°C, approx. 400 and 1100 µatm, respectively), in a fully crossed experimental design. Using micro-computed tomography, hydroxyapatite density was estimated in the mineralized portion of the cartilage in jaws, crura, vertebrae, denticles and pectoral fins of juvenile skates. Mineralization increased as a consequence of high CO 2 in the cartilage of crura and jaws, while temperature decreased mineralization in the pectoral fins. Mineralization affects stiffness and strength of skeletal elements linearly, with implications for feeding and locomotion performance and efficiency. This study is, to my knowledge, the first to quantify a significant change in mineralization in the skeleton of a fish and shows that changes in temperature and pH of the oceans have complex effects on fish skeletal morphology.
26
ROJAS-PADILLA, OMAR, GIUSSEPE GAGLIARDI-URRUTIA, EHIKO J. RIOS-ALVA, and SANTIAGO CASTROVIEJO-FISHER. "A new species of Chiasmocleis Méhely, 1904 (Anura: Microhylidae) from the Peruvian Amazonia." Zootaxa 5195, no. 1 (October 10, 2022): 24–50. http://dx.doi.org/10.11646/zootaxa.5195.1.2.
Анотація:
We describe a new species of Chiasmocleis from the Amazonian forest of Peru. The new species is characterized by its medium size (snout-to-vent length = 18.2–20.8 mm in females, and 16.5 mm in one male), hands and feet with slightly developed fridges in females (more developed in male), and presence of a femoral line in all individuals. We also infer its phylogenetic position using DNA sequences of fragments of the mitochondrial genes for 16S rRNA and cytochrome oxidase subunit 1 (COI), and describe the mineralized skeleton through 3D models generated by computed tomography (CT-scan). Based on our results, we discuss the variation of some osteological characters traditionally used in the systematics of the genus.
27
Ehrlich, Hermann, Vasilii V. Bazhenov, Cecile Debitus, Nicole de Voogd, Roberta Galli, Mikhail V. Tsurkan, Marcin Wysokowski, et al. "Isolation and identification of chitin from heavy mineralized skeleton of Suberea clavata (Verongida: Demospongiae: Porifera) marine demosponge." International Journal of Biological Macromolecules 104 (November 2017): 1706–12. http://dx.doi.org/10.1016/j.ijbiomac.2017.01.141.
28
Leggio, Alessia, and Francesco Introna. "Fully Ossified Thyroid Cartilage Found among the Skeletal Remains of A 21-Year-Old Slavic Soldier: Interpretation of a Case." Forensic Sciences 1, no. 3 (December 5, 2021): 213–19. http://dx.doi.org/10.3390/forensicsci1030019.
Анотація:
The degree of ossification of the thyroid cartilage in anthropological studies is related to other methods of determining the age of a skeleton. The endochondral ossification process begins at the age of approximately 15–20 years and is generally completed in the fifth or sixth decade of life. In the present case, early and complete mineralization of the thyroid cartilage of a skeleton belonging to a 21-year-old young soldier who died in 1946 was observed. Ossified thyroid cartilage at a very young age is rare and may be associated with specific symptoms, such as compression due to trauma, or may also be related to hormonal dysfunction and various diseases that may cause early mineralization. A macroscopic morphological evaluation and radiographic examination of the thyroid cartilage were performed and a decalcification test was applied to a sample taken from the thyroid cartilage to confirm that the structure was indeed mineralized. There is nothing to exclude that this is simply a physiological anatomical variation. Knowledge of this rare anatomical abnormality at a young age would be useful for the diagnosis of various pathological conditions.
29
Toshchev, А. G., L. F. Kaskova, and А. V. Аrtemev. "THE VIEW ON THE DENTAL MORBIDITY INDICATORS OF THE CHILDREN UKRAINIAN NOGAI POPULATION AT THE XV CENTURY DEALS WITH THE NEW STUDYING METHODS USED FOR ANTHROPOLOGICAL MATERIAL FROM THE MAMAY GORA BURIAL GROUND." Ukrainian Dental Almanac, no. 3 (September 23, 2020): 62–68. http://dx.doi.org/10.31718/2409-0255.3.2020.10.
Анотація:
The subject matter was the children dental status having involved in study anthropological bone material different historical eras. The 133 remains skeletons of children were examined. The control and main groups consisted with the skeletons of children who had lived in the Nogai and Golden Horde periods, respectively, which in turn the last included children skeletons of earlier historical times.
The author’s method was used in our scientific research. The ancient people skeletons were examined in historical and medical anthropology laboratory of the municipal institution “Conservation Centre and Research of Archaeological Monuments” of the Poltava Regional Council and the Department of Pediatric Therapeutic Dentistry with the Dental Diseases Prevention UMSA.
The control group has included the children with maxillofacial pathology but their musculoskeletal system hasn’t been changed. However, two children have a “thin line” dental deposit in permanent and primary teeth.
Two enamel hypoplasia specimens were detected in bone materials, five specimens of anomalies development dento-maxillofacial region and two dental specimens with markers determined of social society affiliation in the main children's group of the Middle Ages consist with of Golden Horde children. The main group results were compared with control group related to one period.
The increase in the incidence of dental pathology was directly proportional to the number of children examined in the group.
The dental pathology incidence was directly proportional relation increases to the examined children quantity in the group. The bone skeleton injury was found only in Golden Horde children group. The Middle Ages is characterized with the average diseases prevalence in Europe and America populations.
We were determined the carious process and periodontal pathology were absence in deciduous and permanent teeth in the base and control children groups represent Middle Ages, after morphological and statistical processing of the collected archaeological, bone material.
The dental mineralized deposits have a similar shape in base and control groups children of the Middle Ages in the studied territory of Ukraine.
The dental mineralized plaque had a huge volume and was occupied a massive teeth square in examined children group identified with earlier historical periods and the Middle Ages. The research has shown that the dental deposit has a gradual evolutionary development in teeth of children groups at the Middle Ages.
30
Cunningham, John A., Martin Rücklin, Henning Blom, Hector Botella, and Philip C. J. Donoghue. "Testing models of dental development in the earliest bony vertebrates, Andreolepis and Lophosteus." Biology Letters 8, no. 5 (May 23, 2012): 833–37. http://dx.doi.org/10.1098/rsbl.2012.0357.
Анотація:
Theories on the development and evolution of teeth have long been biased by the fallacy that chondrichthyans reflect the ancestral condition for jawed vertebrates. However, correctly resolving the nature of the primitive vertebrate dentition is challenged by a dearth of evidence on dental development in primitive osteichthyans. Jaw elements from the Silurian–Devonian stem-osteichthyans Lophosteus and Andreolepis have been described to bear a dentition arranged in longitudinal rows and vertical files, reminiscent of a pattern of successional development. We tested this inference, using synchrotron radiation X-ray tomographic microscopy (SRXTM) to reveal the pattern of skeletal development preserved in the sclerochronology of the mineralized tissues. The tooth-like tubercles represent focal elaborations of dentine within otherwise continuous sheets of the dermal skeleton, present in at least three stacked generations. Thus, the tubercles are not discrete modular teeth and their arrangement into rows and files is a feature of the dermal ornamentation that does not reflect a polarity of development or linear succession. These fossil remains have no bearing on the nature of the dentition in osteichthyans and, indeed, our results raise questions concerning the homologies of these bones and the phylogenetic classification of Andreolepis and Lophosteus .
31
Ko, J. Y., E. Lee, J. Kim, and G. I. Im. "AB0074 KRÜPPEL-LIKE FACTOR 10 IS A IMPORTANT MODULATORY FACTOR OF CHONDROCYTE HYPERTROPHY IN DEVELOPING SKELETON." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1337.1–1337. http://dx.doi.org/10.1136/annrheumdis-2020-eular.2065.
Анотація:
Background:To investigate the functional role of KLF10 as a modulator of chondrocyte hypertrophy in developmental skeleton, the developmental characteristics in the long bone of KLF10 knockout mice and characteristics of MSCs from KLF10 KO mice were investigated regarding chondrogenesis and osteogenesis. Delayed long bone growth and delayed formation of primary ossification center were observed in an early embryonic stage in KLF10 KO mouse along with very low Ihh expression in epiphyseal plate. While the chondrogenic potential of mMSCs appeared normal or slight decrerased in KLF10 KO mice, osteogenesis and hypertrophy were extensively suppressed. KLF10 was found to be a mediator of chondrocyte hypertrophy in developing skeleton. Suppression of KLF10 may be considered as a new strategy for preventing hypertrophy in cartilage regeneration using MSCs.Objectives:Investigated the functional role of KLF10 to present new insights into the transcriptional network regulating skeletal development and provide a novel strategy for preventing aberrant hypertrophic differentiation in cartilage regeneration strategies using MSCs.Methods:Generation of KLF10 KO mice and genotyping / Skeletal preparations, embryo heights, and mineralized bone length measurements / Histological and Fluorescent Immunohistochemical Analysis / ALP staining and activity / Alizarin red staining / Von Kossa staining and calcium salts quantification / Isolation and Establishment of Mouse Clonal MSC Lines / Chondrogenic pellet culture and differentiation of mMSCs / DNA Quantification and GAG Contents Analysis / Rq-PCR Analysis / StatisticsResults:The overall results showed that mMSCs from KLF10 KO mice have significantly decreased osteogenic potential with very low Ihh expression while an increase in chondrogenic potential was not significant. In addition to Ihh promotor demonstrated in our previous study, KLF10 can activate Runx2 expression through its proximal-promoter region. Thus, KLF10 may indirectly stimulate Ihh expression upstream of Runx2 or directly bind to Ihh promoter and activate Ihh expression. As shown in this and out previous study, KLF10 also enhances Wnt/β-catenin signalling in MSCs. KLF10 modulates β-catenin sub-cellular localization and enhances Wnt signalling in osteoblasts.Conclusion:In conclusion, primary ossification in KLF10 KO mice was critically delayed during early endochondral bone development. KLF10 KO inhibited hypertrophy via reduced Ihh expression in developing skeleton. TGF-β-induced hypertrophy was inhibited during chondrogenesis of KLF10 KO mMSCs. Our findings present new insights into the transcriptional-network system of skeletal development and provide a novel strategy for suppressing hypertrophy in cartilage tissue engineering.Figure.Acknowledgments:This research was supported by the National Research Foundation of Korea (NRF-2019R1H1A2039685 and 2019R1I1A1A01043778).Disclosure of Interests:None declared
32
Fernández-Iglesias, Ángela, Rocío Fuente, Helena Gil-Peña, Laura Alonso-Durán, Fernando Santos, and José Manuel López. "The Formation of the Epiphyseal Bone Plate Occurs via Combined Endochondral and Intramembranous-Like Ossification." International Journal of Molecular Sciences 22, no. 2 (January 18, 2021): 900. http://dx.doi.org/10.3390/ijms22020900.
Анотація:
The formation of the epiphyseal bone plate, the flat bony structure that provides strength and firmness to the growth plate cartilage, was studied in the present study by using light, confocal, and scanning electron microscopy. Results obtained evidenced that this bone tissue is generated by the replacement of the lower portion of the epiphyseal cartilage. However, this process differs considerably from the usual bone tissue formation through endochondral ossification. Osteoblasts deposit bone matrix on remnants of mineralized cartilage matrix that serve as a scaffold, but also on non-mineralized cartilage surfaces and as well as within the perivascular space. These processes occur simultaneously at sites located close to each other, so that, a core of the sheet of bone is established very quickly. Subsequently, thickening and reshaping occurs by appositional growth to generate a dense parallel-fibered bone structurally intermediate between woven and lamellar bone. All these processes occur in close relationship with a cartilage but most of the bone tissue is generated in a manner that may be considered as intramembranous-like. Overall, the findings here reported provide for the first time an accurate description of the tissues and events involved in the formation of the epiphyseal bone plate and gives insight into the complex cellular events underlying bone formation at different sites on the skeleton.
33
Fang, Renpeng, Coline Haxaire, Miguel Otero, Samantha Lessard, Gisela Weskamp, David R. McIlwain, Tak W. Mak, Stefan F. Lichtenthaler, and Carl P. Blobel. "Role of iRhoms 1 and 2 in Endochondral Ossification." International Journal of Molecular Sciences 21, no. 22 (November 19, 2020): 8732. http://dx.doi.org/10.3390/ijms21228732.
Анотація:
Growth of the axial and appendicular skeleton depends on endochondral ossification, which is controlled by tightly regulated cell–cell interactions in the developing growth plates. Previous studies have uncovered an important role of a disintegrin and metalloprotease 17 (ADAM17) in the normal development of the mineralized zone of hypertrophic chondrocytes during endochondral ossification. ADAM17 regulates EGF-receptor signaling by cleaving EGFR-ligands such as TGFα from their membrane-anchored precursor. The activity of ADAM17 is controlled by two regulatory binding partners, the inactive Rhomboids 1 and 2 (iRhom1, 2), raising questions about their role in endochondral ossification. To address this question, we generated mice lacking iRhom2 (iR2−/−) with floxed alleles of iRhom1 that were specifically deleted in chondrocytes by Col2a1-Cre (iR1∆Ch). The resulting iR2−/−iR1∆Ch mice had retarded bone growth compared to iR2−/− mice, caused by a significantly expanded zone of hypertrophic mineralizing chondrocytes in the growth plate. Primary iR2−/−iR1∆Ch chondrocytes had strongly reduced shedding of TGFα and other ADAM17-dependent EGFR-ligands. The enlarged zone of mineralized hypertrophic chondrocytes in iR2−/−iR1∆Ch mice closely resembled the abnormal growth plate in A17∆Ch mice and was similar to growth plates in Tgfα−/− mice or mice with EGFR mutations. These data support a model in which iRhom1 and 2 regulate bone growth by controlling the ADAM17/TGFα/EGFR signaling axis during endochondral ossification.
34
Vannucci, Letizia, Caterina Fossi, Sara Quattrini, Leonardo Guasti, Barbara Pampaloni, Giorgio Gronchi, Francesca Giusti, et al. "Calcium Intake in Bone Health: A Focus on Calcium-Rich Mineral Waters." Nutrients 10, no. 12 (December 5, 2018): 1930. http://dx.doi.org/10.3390/nu10121930.
Анотація:
Calcium is an essential element that plays numerous biological functions in the human body, of which one of the most important is skeleton mineralization. Bone is a mineralized connective tissue in which calcium represents the major component, conferring bone strength and structure. Proper dietary calcium intake is important for bone development and metabolism, and its requirement can vary throughout life. The mineral composition of drinking water is becoming relevant in the modulation of calcium homeostasis. In fact, calcium present in mineral drinking waters is an important quantitative source of calcium intake. This, together with its excellent bioavailability, contributes to the maintenance of the bone health. This article aims to examine studies that assessed the bioavailability of the calcium contained in calcium-rich mineral waters and their impact on bone health, including original data collected in a recent study in humans.
35
Suzuki, Akiko, Mina Minamide, Chihiro Iwaya, Kenichi Ogata, and Junichi Iwata. "Role of Metabolism in Bone Development and Homeostasis." International Journal of Molecular Sciences 21, no. 23 (November 26, 2020): 8992. http://dx.doi.org/10.3390/ijms21238992.
Анотація:
Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies.
36
ZUCCHETTI, VICTOR M., OMAR ROJAS-PADILLA, IURI R. DIAS, MIRCO SOLÉ, VICTOR G. D. ORRICO, and SANTIAGO CASTROVIEJO-FISHER. "An elusive giant: A new species of Vitreorana Guayasamin et al., 2009 (Anura: Centrolenidae) from the northern Atlantic Forest with an osteological description and comments on integumentary spicules." Zootaxa 5249, no. 3 (March 2, 2023): 301–34. http://dx.doi.org/10.11646/zootaxa.5249.3.1.
Анотація:
We describe a new species of Vitreorana from the Atlantic Forest of southern Bahia state, in north-eastern Brazil. Vitreorana assuh sp. nov. is by far the largest species of the genus (snout-to-vent length [SVL] = 30.9 mm and 34.1 mm in one male and female, respectively; maximum SVL recorded for all other species = 28.0 mm). The new species is morphologically most similar to V. franciscana, from the Cerrado biome in Brazil. Besides its large size, the new species has, among other diagnostic characters, the presence of vomerine teeth and the occurrence of enameled iridophores in the pericardium, hepatic and urinary bladder peritonea. Furthermore, we describe and compare the complete mineralized skeleton of the new species and V. uranoscopa, and describe and discuss the variation of integumentary spicules in all species of the genus and their relevance to Vitreorana systematics.
37
Taylor, Paul D., Björn Berning, and Mark A. Wilson. "Reinterpretation of the Cambrian ‘bryozoan’ Pywackia as an octocoral." Journal of Paleontology 87, no. 6 (November 2013): 984–90. http://dx.doi.org/10.1666/13-029.
Анотація:
Pywackia baileyi Landing in Landing et al., 2010, from the upper Cambrian Yudachica Member of Oaxaca State, southern Mexico, consists of small, phosphatic, proximally tapering cylindrical rods covered by shallow polygonal calices. The bryozoan-like morphology of this fossil prompted its interpretation as the first bryozoan known from the Cambrian. However, restudy of some of the original material, employing scanning electron microscopy for the first time, questions the assignment of Pywackia to the Bryozoa. Striking similarities between Pywackia and the modern pennatulacean octocoral Lituaria lead to an alternative hypothesis interpreting Pywackia an early fossil octocoral. While Pywackia is probably not a true pennatulacean, a group with a definitive fossil record stretching back only to the Late Cretaceous, it can be envisaged as having had a similar skeletal structure and ecology to Lituaria, the rods representing mineralized axes of tiny colonies that lived with their proximal ends buried in the sediment and distal ends covered by feeding polyps. Landing et al. (2010) considered the phosphatic composition of Pywackia specimens to be the result of diagenetic replacement, but the evidence is equivocal. If Pywackia had a primary phosphatic skeleton, this would support the hypothesized existence of phosphatic biomineralization early in the evolutionary history of Cnidaria, as well as providing further evidence that Pywackia is not a bryozoan.
38
Hayman, A. R., S. J. Jones, A. Boyde, D. Foster, W. H. Colledge, M. B. Carlton, M. J. Evans, and T. M. Cox. "Mice lacking tartrate-resistant acid phosphatase (Acp 5) have disrupted endochondral ossification and mild osteopetrosis." Development 122, no. 10 (October 1, 1996): 3151–62. http://dx.doi.org/10.1242/dev.122.10.3151.
Анотація:
Mature osteoclasts specifically express the purple, band 5 isozyme (Acp 5) of tartrate-resistant acid phosphatase, a binuclear metalloenzyme that can generate reactive oxygen species. The function of Acp 5 was investigated by targeted disruption of the gene in mice. Animals homozygous for the null Acp 5 allele had progressive foreshortening and deformity of the long bones and axial skeleton but apparently normal tooth eruption and skull plate development, indicating a role for Acp 5 in endochondral ossification. Histomorphometry and mineralization density analysis of backscattered electron imaging revealed widened and disorganized epiphyseal growth plates with delayed mineralization of cartilage in 6- to 8-week-old mutant mice. The membrane bones of the skull showed increased density at all ages examined, indicating defective osteoclastic bone turnover. Increased mineralization density was observed in the long bones of older animals which showed modelling deformities at their extremities: heterozygotes and homozygous Acp 5 mutant mice had tissue that was more mineralized and occupied a greater proportion of the bone in all regions. Thus the findings reflect a mild osteopetrosis due to an intrinsic defect of osteoclastic modelling activity that was confirmed in the resorption pit assay in vitro. We conclude that this bifunctional metalloprotein of the osteoclast is required for normal mineralization of cartilage in developing bones; it also maintains integrity and turnover of the adult skeleton by a critical contribution to bone matrix resorption.
39
Gnyubkin, Vasily, Alain Guignandon, Norbert Laroche, Arnaud Vanden-Bossche, Myriam Normand, Marie-Hélène Lafage-Proust, and Laurence Vico. "Effects of chronic hypergravity: from adaptive to deleterious responses in growing mouse skeleton." Journal of Applied Physiology 119, no. 8 (October 15, 2015): 908–17. http://dx.doi.org/10.1152/japplphysiol.00364.2015.
Анотація:
One of the most important but least studied environmental factors playing a major role in bone physiology is gravity. While the knowledge of deleterious effects of microgravity on the skeleton is expanding, little is known about hypergravity and its osteogenic potential. Centrifugation was used to assess effects of 21-day continuous 2- or 3- g acceleration on femur and L2-vertebra of 7-wk-old male C57BL/6 mice. Under 3 g, body mass growth slowed down, and deleterious skeletal effects were found ( P < 0.05 compared with control): cortical thinning, osteoclasts surface increase (+41% in femur, +20% in vertebra), and bone formation rate decrease (−34% in femur, −38% in vertebra). A 2- g centrifugation did not reduce body mass and improved trabecular volume (+18% in femur, +13% in vertebra) and microarchitecture (+32% connectivity density in femur, +9% trabecular thickness in vertebra, P < 0.05 compared with control). Centrifugation at 2 g also decreased osteoclast surfaces (−36% in femur, −16% in vertebra) and increased the extent of mineralized surfaces (+31% in femur, +48% in vertebra, P < 0.05 compare to control). Quantitative immunohistochemistry revealed an increase of dentin matrix acidic phosphoprotein 1 (DMP1) and decrease of sclerostin (+60% and −35% respectively, P < 0.001 compared with control) in the femur cortex of 2- g mice. In the distal femur metaphysis, the number and volume of blood vessels increased by 22 and 44%, respectively ( P < 0.05 compared with control). In conclusion, the effects of continuous hypergravity were bone compartment-specific and depended on the gravity level, with a threshold between beneficial 2- g and deleterious 3- g effects.
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Roberts, W. Eugene, Jonathan E. Mangum, and Paul M. Schneider. "Pathophysiology of Demineralization, Part II: Enamel White Spots, Cavitated Caries, and Bone Infection." Current Osteoporosis Reports 20, no. 1 (February 2022): 106–19. http://dx.doi.org/10.1007/s11914-022-00723-0.
Анотація:
Abstract Purpose of Review Compare noninfectious (part I) to infectious (part II) demineralization of bones and teeth. Evaluate similarities and differences in the expression of hard tissue degradation for the two most common chronic demineralization diseases: osteoporosis and dental caries. Recent Findings The physiology of demineralization is similar for the sterile skeleton compared to the septic dentition. Superimposing the pathologic variable of infection reveals a unique pathophysiology for dental caries. Summary Mineralized tissues are compromised by microdamage, demineralization, and infection. Osseous tissues remodel (turnover) to maintain structural integrity, but the heavily loaded dentition does not turnover so it is ultimately at risk of collapse. A carious tooth is a potential vector for periapical infection that may be life-threatening. Insipient caries is initiated as a subsurface decalcification in enamel that is not detectable until a depth of ~400μm when it becomes visible as a white spot. Reliable detection and remineralization of invisible caries would advance cost-effective wellness worldwide.
41
Mozingo, Nancy M. "Lectin uptake and incorporation into the calcitic spicule of sea urchin embryos." Zygote 23, no. 3 (April 15, 2014): 467–73. http://dx.doi.org/10.1017/s0967199414000094.
Анотація:
SummaryPrimary mesenchyme cells (PMCs) are skeletogenenic cells that produce a calcareous endoskeleton in developing sea urchin larvae. The PMCs fuse to form a cavity in which spicule matrix proteins and calcium are secreted forming the mineralized spicule. In this study, living sea urchin embryos were stained with fluorescently conjugated wheat germ agglutinin, a lectin that preferentially binds to PMCs, and the redistribution of this fluorescent tag was examined during sea urchin development. Initially, fluorescence was associated primarily with the surface of PMCs. Subsequently, the fluorescent label redistributed to intracellular vesicles in the PMCs. As the larval skeleton developed, intracellular granular staining diminished and fluorescence appeared in the spicules. Spicules that were cleaned to remove membranous material associated with the surface exhibited bright fluorescence, which indicated that fluorescently labelled lectin had been incorporated into the spicule matrix. The results provide evidence for a cellular pathway in which material is taken up at the cell surface, sequestered in intracellular vesicles and then incorporated into the developing spicule.
42
Johanson, Zerina, Moya Smith, Sophie Sanchez, Tim Senden, Kate Trinajstic, and Cathrin Pfaff. "Questioning hagfish affinities of the enigmatic Devonian vertebrate Palaeospondylus." Royal Society Open Science 4, no. 7 (July 2017): 170214. http://dx.doi.org/10.1098/rsos.170214.
Анотація:
Palaeospondylus gunni Traquair, 1890 is an enigmatic Devonian vertebrate whose taxonomic affinities have been debated since it was first described. Most recently, Palaeospondylus has been identified as a stem-group hagfish (Myxinoidea). However, one character questioning this assignment is the presence of three semicircular canals in the otic region of the cartilaginous skull, a feature of jawed vertebrates. Additionally, new tomographic data reveal that the following characters of crown-group gnathostomes (chondrichthyans + osteichthyans) are present in Palaeospondylus : a longer telencephalic region of the braincase, separation of otic and occipital regions by the otico-occipital fissure, and vertebral centra. As well, a precerebral fontanelle and postorbital articulation of the palatoquadrate are characteristic of certain chondrichthyans. Similarities in the structure of the postorbital process to taxa such as Pucapampella , and possible presence of the ventral cranial fissure, both support a resolution of Pa. gunni as a stem chondrichthyan. The internally mineralized cartilaginous skeleton in Palaeospondylus may represent a stage in the loss of bone characteristic of the Chondrichthyes.
43
Funato, N., D. Srivastava, S. Shibata, and H. Yanagisawa. "TBX1 Regulates Chondrocyte Maturation in the Spheno-occipital Synchondrosis." Journal of Dental Research 99, no. 10 (May 22, 2020): 1182–91. http://dx.doi.org/10.1177/0022034520925080.
Анотація:
The synchondrosis in the cranial base is an important growth center for the craniofacial region. Abnormalities in the synchondroses affect the development of adjacent regions, including the craniofacial skeleton. Here, we report that the transcription factor TBX1, the candidate gene for DiGeorge syndrome, is expressed in mesoderm-derived chondrocytes and plays an essential and specific role in spheno-occipital synchondrosis development by inhibiting the expression of genes involved in chondrocyte hypertrophy and osteogenesis. In Tbx1-deficient mice, the spheno-occipital synchondrosis was completely mineralized at birth. TBX1 interacts with RUNX2, a master molecule of osteoblastogenesis and a regulator of chondrocyte maturation, and suppresses its transcriptional activity. Indeed, deleting Tbx1 triggers accelerated mineralization due to accelerated chondrocyte differentiation, which is associated with ectopic expression of downstream targets of RUNX2 in the spheno-occipital synchondrosis. These findings reveal that TBX1 acts as a regulator of chondrocyte maturation and osteogenesis during the spheno-occipital synchondrosis development. Thus, the tight regulation of endochondral ossification by TBX1 is crucial for the normal progression of chondrocyte differentiation in the spheno-occipital synchondrosis.
44
Varela, Aurore, and Jacquelin Jolette. "Bone Toolbox: Biomarkers, Imaging Tools, Biomechanics, and Histomorphometry." Toxicologic Pathology 46, no. 5 (July 2018): 511–29. http://dx.doi.org/10.1177/0192623318779565.
Анотація:
Bone is a unique tissue with turnover, metabolic, and cellular activities that vary through development to aging and with a mineralized matrix in which the current state and the history of a bone coexist. Qualitative histopathology often lacks sensitivity to detect changes in bone formation, mineralization and resorption, which often requires chronic dosing to result in structural changes such as variation in bone mass and geometry. A large panel of modalities can be used to fully analyze the health of the skeleton, including biomarker evaluation in serum or urine, imaging techniques ranging from radiology to computed tomography, biomechanical testing, and undecalcified tissue processing with bone histomorphometry. The use of clinically relevant biomarkers provides an important noninvasive, sensitive, rapid, and real-time tool to monitor bone activity at the whole skeleton level when conducting safety assessments in a preclinical setting. Imaging modalities also allow in vivo longitudinal assessments with a powerful, noninvasive and clinically translatable tools to monitor drug effects. Different imaging modalities are used in the preclinical studies to evaluate the bone tissues: standard radiography, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography (pQCT), micro-computed tomography, and high-resolution pQCT. Bone histomorphometry is an important tool that provides sensitive evaluation to detect effects of test articles on bone resorption, formation, mineralization, remodeling rates and growth to address a potential target- or class-related theoretical bone liability. Ultimately, the measurement of bone mechanical properties in pharmaceutical testing is critical to understand the potential effects of that pharmaceutical on bone health and fracture risk. Important considerations are required for including these different techniques in toxicology rodents and nonrodent studies, to actually integrate these into safety assessment.
45
Charoenngam, Nipith. "Vitamin D and Rheumatic Diseases: A Review of Clinical Evidence." International Journal of Molecular Sciences 22, no. 19 (October 1, 2021): 10659. http://dx.doi.org/10.3390/ijms221910659.
Анотація:
Vitamin D plays an important role in maintaining a healthy mineralized skeleton. It is also considered an immunomodulatory agent that regulates innate and adaptive immune systems. The aim of this narrative review is to provide general concepts of vitamin D for the skeletal and immune health, and to summarize the mechanistic, epidemiological, and clinical evidence on the relationship between vitamin D and rheumatic diseases. Multiple observational studies have demonstrated the association between a low level of serum 25-hydroxyvitamin D [25(OH)D] and the presence and severity of several rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropathies, and osteoarthritis (OA). Nevertheless, the specific benefits of vitamin D supplements for the treatment and prevention of rheumatic diseases are less accepted as the results from randomized clinical trials are inconsistent, although some conceivable benefits of vitamin D for the improvement of disease activity of RA, SLE, and OA have been demonstrated in meta-analyses. It is also possible that some individuals might benefit from vitamin D differently than others, as inter-individual difference in responsiveness to vitamin D supplementation has been observed in genomic studies. Although the optimal level of serum 25(OH)D is still debatable, it is advisable it is advisable that patients with rheumatic diseases should maintain a serum 25(OH)D level of at least 30 ng/mL (75 nmol/L) to prevent osteomalacia, secondary osteoporosis, and fracture, and possibly 40–60 ng/mL (100–150 nmol/L) to achieve maximal benefit from vitamin D for immune health and overall health.
46
Ford, Jeffery J., Lee-Chuan C. Yeh, Eric C. Schmidgal, Jason F. Thompson, Martin L. Adamo, and John C. Lee. "Protein Kinase D1 Is Essential for Bone Acquisition during Pubertal Growth." Endocrinology 154, no. 11 (November 1, 2013): 4182–91. http://dx.doi.org/10.1210/en.2013-1376.
Анотація:
Bone formation and maintenance represents the summation of the balance of local and endocrine hormonal stimuli within a complex organ. Protein kinase D (PKD) is a member of the Ca2+/calmodulin-dependent kinase superfamily of serine/threonine kinases and has been described as the crossroads for the bone morphogenetic protein (BMP)-IGF-I signaling axis, which plays a major role in bone formation. The current study exploits the PKD1-deficient mouse model to examine the role of PKD in vivo in the skeleton. Dual-energy x-ray absorptiometry scan analysis of male and female pubescent mice demonstrated significantly decreased bone mineral density in the whole body and femoral bone compartments of PKD1 (+/−) mice, compared with their wild-type littermates. The body weight, nasal-anal length, and percentage body fat of the mice were not significantly different from their wild-type littermates. Cultured bone marrow stromal cells from PKD1 (+/−) mice demonstrated lower alkaline phosphatase activity in early differentiating osteoblasts and decreased mineralized nodule formation in mature osteoblasts. Quantitative RT-PCR analysis of osteoblast differentiation markers and osteoclast markers exhibited lower levels of expression in PKD1 (+/−) male mice than wild type. In female mice, however, only markers of osteoblast differentiation were reduced. PKD1 (+/−) mice also demonstrated a profound reduction in mRNA expression levels of BMP type II receptor and IGF-I receptor and in BMP-7 responsiveness in vitro. Together these data suggest that in mice, PKD1 action contributes to the regulation of osteoblastogenesis by altering gene expression with gender-specific effects on osteoclastogenesis, subsequently affecting skeletal matrix acquisition during puberty.
47
Fudge, Neva J., and Christopher S. Kovacs. "Pregnancy Up-Regulates Intestinal Calcium Absorption and Skeletal Mineralization Independently of the Vitamin D Receptor." Endocrinology 151, no. 3 (January 5, 2010): 886–95. http://dx.doi.org/10.1210/en.2009-1010.
Анотація:
Without the vitamin D receptor (VDR), adult mammals develop reduced intestinal calcium absorption, rickets, and osteomalacia. Intestinal calcium absorption normally increases during pregnancy so that the mother can supply sufficient calcium to her fetuses. The maternal skeleton is rapidly resorbed during lactation to provide calcium needed for milk; that lost bone mineral content (BMC) is completely restored after weaning. We studied Vdr null mice to determine whether these adaptations during pregnancy and lactation require the VDR. Vdr nulls were severely rachitic at 10 wk of age on a normal diet. Pregnancy induced a 158% increase in Vdr null BMC to equal the pregnant wild-type (WT) value. Lactation caused BMC losses that were equal in Vdr nulls and WT. Vdr nulls recovered after weaning to a BMC 50% higher than before pregnancy and equal to WT. Additional analyses showed that during pregnancy, duodenal 45Ca absorption increased in Vdr nulls, secondary hyperparathyroidism lessened, bone turnover markers decreased, and osteoid became fully mineralized. A genome-wide microarray analysis of duodenal RNA found marked reduction of Trpv6 in Vdr nulls at baseline but a 13.5-fold increase during pregnancy. Calbindin D-9K (S100g) and Ca2+-ATPase (Pmca1) were not altered by pregnancy. Several other solute transporters increased during pregnancy in Vdr nulls. In summary, Vdr nulls adapt to pregnancy by up-regulating duodenal Trpv6 and intestinal 45Ca absorption, thereby enabling rapid normalization of BMC during pregnancy. These mice lactate normally and fully restore BMC after weaning. Therefore, VDR is not required for the skeletal adaptations during pregnancy, lactation, and after weaning.
48
Neubauer, Vanessa J., Florian Hüter, Johannes Wittmann, Vanessa T. Trossmann, Claudia Kleinschrodt, Bettina Alber-Laukant, Frank Rieg, and Thomas Scheibel. "Flow Simulation and Gradient Printing of Fluorapatite- and Cell-Loaded Recombinant Spider Silk Hydrogels." Biomolecules 12, no. 10 (October 3, 2022): 1413. http://dx.doi.org/10.3390/biom12101413.
Анотація:
Hierarchical structures are abundant in almost all tissues of the human body. Therefore, it is highly important for tissue engineering approaches to mimic such structures if a gain of function of the new tissue is intended. Here, the hierarchical structures of the so-called enthesis, a gradient tissue located between tendon and bone, were in focus. Bridging the mechanical properties from soft to hard secures a perfect force transmission from the muscle to the skeleton upon locomotion. This study aimed at a novel method of bioprinting to generate gradient biomaterial constructs with a focus on the evaluation of the gradient printing process. First, a numerical approach was used to simulate gradient formation by computational flow as a prerequisite for experimental bioprinting of gradients. Then, hydrogels were printed in a single cartridge printing set-up to transfer the findings to biomedically relevant materials. First, composites of recombinant spider silk hydrogels with fluorapatite rods were used to generate mineralized gradients. Then, fibroblasts were encapsulated in the recombinant spider silk-fluorapatite hydrogels and gradually printed using unloaded spider silk hydrogels as the second component. Thereby, adjustable gradient features were achieved, and multimaterial constructs were generated. The process is suitable for the generation of gradient materials, e.g., for tissue engineering applications such as at the tendon/bone interface.
49
Foster, B. L., Y. Soenjaya, F. H. Nociti, E. Holm, P. M. Zerfas, H. F. Wimer, D. W. Holdsworth, et al. "Deficiency in Acellular Cementum and Periodontal Attachment in Bsp Null Mice." Journal of Dental Research 92, no. 2 (November 26, 2012): 166–72. http://dx.doi.org/10.1177/0022034512469026.
Анотація:
Bone sialoprotein (BSP) is an extracellular matrix protein found in mineralized tissues of the skeleton and dentition. BSP is multifunctional, affecting cell attachment and signaling through an RGD integrin-binding region, and acting as a positive regulator for mineral precipitation by nucleating hydroxyapatite crystals. BSP is present in cementum, the hard tissue covering the tooth root that anchors periodontal ligament (PDL) attachment. To test our hypothesis that BSP plays an important role in cementogenesis, we analyzed tooth development in a Bsp null (-/-) mouse model. Developmental analysis by histology, histochemistry, and SEM revealed a significant reduction in acellular cementum formation on Bsp-/- mouse molar and incisor roots, and the cementum deposited appeared hypomineralized. Structural defects in cementum-PDL interfaces in Bsp-/- mice caused PDL detachment, likely contributing to the high incidence of incisor malocclusion. Loss of BSP caused progressively disorganized PDL and significantly increased epithelial down-growth with aging. Bsp-/- mice displayed extensive root and alveolar bone resorption, mediated by increased RANKL and the presence of osteoclasts. Results collected here suggest that BSP plays a non-redundant role in acellular cementum formation, likely involved in initiating mineralization on the root surface. Through its importance to cementum integrity, BSP is essential for periodontal function.
50
Warren, Daniel E., and Donald C. Jackson. "Effects of temperature on anoxic submergence: skeletal buffering, lactate distribution, and glycogen utilization in the turtle, Trachemys scripta." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, no. 1 (July 2007): R458—R467. http://dx.doi.org/10.1152/ajpregu.00174.2006.
Анотація:
To test the hypothesis that submergence temperature affects the distribution of the lactate load and glycogen utilization during anoxia in turtles, we sampled a variety of tissues after 7 days, 24 h, and 4 h of anoxic submergence at 5, 15, and 25°C, respectively. These anoxic durations were chosen because we found that they produced similar decreases in plasma HCO3− (∼18–22 meq/l). The sampled tissues included ventricle, liver, small intestine, carapace, and the following muscles: flexor digitorum longus, retrahens capitis, iliofibularis, and pectoralis. Shell and skeleton sequestered 41.9, 34.1, and 26.1% of the estimated lactate load at 5, 15, and 25°C. The changes in plasma Ca2+ and Mg2+, relative to the estimated lactate load, decreased with increased temperature, indicating greater buffer release from bone at colder temperatures. Tissue lactate contents, relative to plasma lactate, increased with the temperature of the submergence. Glucose mobilization and tissue glycogen utilization were more pronounced at 15 and 25°C than at 5°C. We conclude that, in slider turtles, the ability of the mineralized tissue to participate in the buffering of lactic acid during anoxia is inversely related to temperature, causing the lactate burden to shift to the tissues at warmer temperatures. Muscles utilize glycogen during anoxia more at warmer temperatures.