Shell regeneration in Helix: shell matrix composition and crystal formation

1969 ◽  
Vol 47 (6) ◽  
pp. 1107-1111 ◽  
Author(s):  
A. S. M. Saleuddin ◽  
Wilson Chan
Keyword(s):  
Chemical Nature ◽  
Early Stage ◽  
Organic Matrix ◽  
Matrix Composition ◽  
Crystal Formation ◽  
Shell Matrix ◽  
Nucleation Sites ◽  
Small Crystals ◽  
Short Period ◽  
Shell Regeneration

The chemical nature of the electron-dense areas appearing on the organic matrix during the early stage of shell regeneration in Helix has been ascertained. These areas of 500–5000 Å are made up mainly of acid mucopolysaccharides as detected by thorium staining. When treated by 1% phosphotungstic acid (PTA) for a short period, these electron-dense areas took up the stain, suggesting the presence of mucoprotein and glycoproteins, and are probably the nucleation sites for calcification because small crystals of CaCO3 appear with them. The small crystals join to form larger ones. Crystals grow presumably by dendritic growth, and eventually form a calcified layer. Electron diffraction studies on these crystals show the presence of aragonite (type present in the normal shell) and calcite.

First Experimental Evidence for Human Dentine Crystal Formation Involving Conversion of Octacalcium Phosphate to Hydroxyapatite

1998 ◽  
Vol 54 (6) ◽  
pp. 1377-1381 ◽  
Author(s):  
Patricia Bodier-Houllé ◽  
Pierre Steuer ◽  
Jean-Claude Voegel ◽  
Frédéric J. G. Cuisinier
Keyword(s):  
Organic Matrix ◽  
Octacalcium Phosphate ◽  
Apatite Crystal ◽  
Crystal Formation ◽  
Complex Process ◽  
Small Crystals ◽  
Slow Kinetics ◽  
Calcified Tissue ◽  
Human Dentine ◽  
Cellular Control

Biological apatite-crystal formation is a complex process starting with heterogeneous nucleation of inorganic calcium phosphate on an organic extracellular matrix [Cuisinier et al. (1995), J. Cryst. Growth, 156, 443–453]. Further stages of crystal growth are also controlled by the organic matrix and both nucleation and growth processes are under cellular control [Mann (1993), Nature (London), 367, 499–505]. The final mineral in calcified tissue is constituted by poorly crystalline hydroxyapatite (HA) with a low Ca:P ratio, containing foreign ions such as carbonate and fluoride. This study reports the first observation of octacalcium phosphate (OCP) [Brown (1962), Nature (London), 196, 1048–1055] in a biological tissue; OCP was found in the central part and HA at the extremities of the same crystal of calcifying dentine. This observation is of key importance in understanding the first nucleation steps of biological mineralization. The presence of OCP in a forming human dentine crystal and the observation in the same tissue of nanometer-sized particles with a HA structure [Houllé et al. (1997), J. Dent Res. 76, 895–904] clearly proves that two mechanisms, direct nucleation of non-stoichiometric HA crystals and nucleation of OCP, occur simultaneously in same area of mineralization. OCP is found to be a transient phase during the growth of biological crystals. In small crystals, OCP is completely transformed into HA by a hydrolysis reaction (Brown, 1962) and can only be detected in larger crystals because of its slow kinetics of transformation.

scholarly journals One Week of CDAHFD Induces Steatohepatitis and Mitochondrial Dysfunction with Oxidative Stress in Liver

2021 ◽  
Vol 22 (11) ◽  
pp. 5851
Author(s):  
Takehito Sugasawa ◽  
Seiko Ono ◽  
Masato Yonamine ◽  
Shin-ichiro Fujita ◽  
Yuki Matsumoto ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Dysfunction ◽  
High Fat Diet ◽  
Early Stage ◽  
Droplet Deposition ◽  
Nonalcoholic Fatty Liver ◽  
Stress Markers ◽  
Mitochondrial Dna Copy Number ◽  
Short Period ◽  
And Oxidative Stress

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been rapidly increasing worldwide. A choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) has been used to create a mouse model of nonalcoholic steatohepatitis (NASH). There are some reports on the effects on mice of being fed a CDAHFD for long periods of 1 to 3 months. However, the effect of this diet over a short period is unknown. Therefore, we examined the effect of 1-week CDAHFD feeding on the mouse liver. Feeding a CDAHFD diet for only 1-week induced lipid droplet deposition in the liver with increasing activity of liver-derived enzymes in the plasma. On the other hand, it did not induce fibrosis or cirrhosis. Additionally, it was demonstrated that CDAHFD significantly impaired mitochondrial respiration with severe oxidative stress to the liver, which is associated with a decreasing mitochondrial DNA copy number and complex proteins. In the gene expression analysis of the liver, inflammatory and oxidative stress markers were significantly increased by CDAHFD. These results demonstrated that 1 week of feeding CDAHFD to mice induces steatohepatitis with mitochondrial dysfunction and severe oxidative stress, without fibrosis, which can partially mimic the early stage of NASH in humans.

Carbon metabolism snapshot by ddPCR during the early step of Candida albicans phagocytosis by macrophages

2020 ◽  
Vol 78 (1) ◽  
Author(s):  
Romain Laurian ◽  
Cécile Jacot-des-Combes ◽  
Fabiola Bastian ◽  
Karine Dementhon ◽  
Pascale Cotton
Keyword(s):  
Carbon Metabolism ◽  
Early Stage ◽  
Yeast Cells ◽  
Transcription Level ◽  
Digital Droplet Pcr ◽  
Metabolic Genes ◽  
Glucose Transport System ◽  
Short Period ◽  
Droplet Pcr ◽  
Alternative Sources

ABSTRACT During Candida macrophage interactions, phagocytosed yeast cells feed in order to grow, develop hyphae and escape. Through numerous proteomic and transcriptomic studies, two metabolic phases have been described. A shift to a starvation mode is generally identified as early as one-hour post phagocytosis, followed by a glycolytic growth mode after C. albicans escaped from the macrophage. Healthy macrophages contain low amounts of glucose. To determine if this carbon source was sensed and metabolized by the pathogen, we explored the transcription level of a delimited set of key genes expressed in C. albicans cells during phagocytosis by macrophages, at an early stage of the interaction. This analysis was performed using a technical digital droplet PCR approach to quantify reliably the expression of carbon metabolic genes after 30 min of phagocytosis. Our data confirm the technique of digital droplet PCR for the detection of C. albicans transcripts using cells recovered after a short period of phagocytosis. At this stage, carbon metabolism is clearly oriented towards the use of alternative sources. However, the activation of high-affinity glucose transport system suggests that the low amount of glucose initially present in the macrophages is detected by the pathogen.

The Possible Calcification Mechanisms in some Reptilian Egg-shells

1959 ◽  
Vol s3-100 (52) ◽  
pp. 529-538
Author(s):  
K. SIMKISS ◽  
C. TYLER
Keyword(s):  
Toluidine Blue ◽  
Organic Matrix ◽  
Acid Mucopolysaccharide ◽  
Amino Group ◽  
Carboxylate Group ◽  
Shell Matrix ◽  
The Matrix ◽  
Egg Shells ◽  
Egg Shell ◽  
Comparison Of The Results

Studies have been made of the organic matrix of certain reptilian egg-shells. The interaction between egg-shell-matrix and various metal ions has been considered by noting the effect of these ions on the staining of the matrix by toluidine blue. A comparison of the results with those for the hen indicates that the chelating mechanism in the Chelonia is similar to that in the hen, but that that in the Crocodilia is different. It is suggested that in the Crocodilia the acid mucopolysaccharide of the matrix is embedded in, but not combined with, the protein and that its chelating mechanism is carboxylate group to carboxylate group, while in the hen and Chelonia, the acid mucopolysaccharide is combined with the protein and that its chelating mechanism is carboxylate group to amino group.

Martensitic Transformation from Ultrafine Grained Austenite Fabricated by ARB in Fe-24Ni-0.3C

2010 ◽  
Vol 667-669 ◽  
pp. 361-366 ◽  
Author(s):  
Hamidreza Jafarian ◽  
Ehsan Borhani ◽  
Akinobu Shibata ◽  
Daisuke Terada ◽  
Nobuhiro Tsuji
Keyword(s):  
Martensitic Transformation ◽  
Accumulative Roll Bonding ◽  
Martensite Transformation ◽  
Early Stage ◽  
Crystallographic Analysis ◽  
High Angle ◽  
Metastable Austenite ◽  
Roll Bonding ◽  
Nucleation Sites ◽  
Ultrafine Grained

In this paper, martensitic transformation from ultrafine grained (UFG) austenite fabricated by accumulative roll bonding (ARB) process in a metastable austenite alloy was studied. Microstructural observations and crystallographic analysis were carried out by FE-SEM/EBSD. The results showed that elongated UFG austenite having 200-300 nm in thickness surrounded by high angle boundaries was obtained after 6 cycles of the ARB process. The martensite transformed from the UFG austenite showed characteristic morphology and texture. The martensite transformation starting (Ms) temperature increased after 1 cycle ARB, which is related to increasing amount of nucleation sites, such as low angle boundaries, introduced during early stage of ARB process. In contrast, by increasing the ARB cycles, Ms temperature decreased. Decreasing the Ms temperature could be correlated to strengthening of austenite by the ARB process.

scholarly journals Dynamics and Spatial Shape of Short-Period Meteoroid Streams

1989 ◽  
Vol 8 ◽  
pp. 287-293 ◽  
Author(s):  
P.B. Babadzhanov ◽  
Yu.V. Obrubov
Keyword(s):  
Early Stage ◽  
Meteor Showers ◽  
Meteoroid Streams ◽  
Small Thickness ◽  
Short Period ◽  
Stream Width ◽  
Different Seasons ◽  
Spatial Shape

AbstractAt the early stage of evolution the meteoroid streams may be considered as elliptical rings of relatively small thickness. The influence of planetary perturbations can essentially increase the stream width and its thickness. As a result one stream may produce several couples of meteor showers active in different seasons of the year. 22 short-period meteoroid streams under review may theoretically produce 104 meteor showers. The existence of 67 is confirmed by observations.

scholarly journals Characterization of the main steps in first shell formation in Mytilus galloprovincialis : possible role of tyrosinase

2019 ◽  
Vol 286 (1916) ◽  
pp. 20192043 ◽  
Author(s):  
A. Miglioli ◽  
R. Dumollard ◽  
T. Balbi ◽  
L. Besnardeau ◽  
L. Canesi
Keyword(s):  
Time Course ◽  
Mytilus Galloprovincialis ◽  
Enzyme Inhibitor ◽  
Organic Matrix ◽  
Mrna Levels ◽  
Shell Formation ◽  
Larval Stages ◽  
Matrix Deposition ◽  
Shell Matrix

Bivalve biomineralization is a highly complex and organized process, involving several molecular components identified in adults and larval stages. However, information is still scarce on the ontogeny of the organic matrix before calcification occurs. In this work, first shell formation was investigated in the mussel Mytilus galloprovincialis . The time course of organic matrix and CaCO 3 deposition were followed at close times post fertilization (24, 26, 29, 32, 48 h) by calcofluor and calcein staining, respectively. Both components showed an exponential trend in growth, with a delay between organic matrix and CaCO 3 deposition. mRNA levels of genes involved in matrix deposition (chitin synthase; tyrosinase- TYR) and calcification (carbonic anhydrase; extrapallial protein) were quantified by qPCR at 24 and 48 hours post fertilization (hpf) with respect to eggs. All transcripts were upregulated across early development, with TYR showing highest mRNA levels from 24 hpf. TYR transcripts were closely associated with matrix deposition as shown by in situ hybridization. The involvement of tyrosinase activity was supported by data obtained with the enzyme inhibitor N-phenylthiourea. Our results underline the pivotal role of shell matrix in driving first CaCO 3 deposition and the importance of tyrosinase in the formation of the first shell in M. galloprovincialis .

scholarly journals STUDIES ON SHELL FORMATION

1961 ◽  
Vol 9 (4) ◽  
pp. 761-771 ◽  
Author(s):  
Norimitsu Watabe ◽  
Karl M. Wilbur
Keyword(s):  
Crystal Growth ◽  
Dendritic Growth ◽  
Three Dimensional ◽  
Outer Part ◽  
Organic Matrix ◽  
Transitional Zone ◽  
Homogeneous State ◽  
Concentration Gradients ◽  
Strong Concentration ◽  
Small Crystals

Details of crystal growth in the calcitostracum of Crassostrea virginica have been studied with the purpose of analyzing the formation of the overlapping rows of oriented tabular crystals characteristic of this part of the shell. Crystal elongation, orientation, and dendritic growth suggest the presence of strong concentration gradients in a thin layer of solution in which crystallization occurs. Formation of the overlapping rows can be explained by three processes observed in the shell: a two-dimensional tree-like dendritic growth in which one set of crystal branchings creeps over an adjacent set of branchings; three-dimensional dendritic growth; and growth by dislocation of crystal surfaces. Multilayers of crystals may thus be formed at one time. This is favored by infrequent secretion of a covering organic matrix which would inhibit crystal growth. The transitional zone covering the outer part of the calcitostracum and the inner part of the prismatic region is generally characterized by aggregates of small crystals with definite orientation. Growth in this zone appears to take place in a relatively homogeneous state of solution without strong concentration gradients. Thin membranes and bands of organic matrix were commonly observed in the transitional zone bordering the prismatic region. The membrane showed a very fine oriented network pattern.

A New Role for Marine Skeletal Proteins in Regenerative Orthopaedics

2012 ◽  
Vol 529-530 ◽  
pp. 654-659
Author(s):  
David W. Green ◽  
Matthew Padula ◽  
Jerran Santos ◽  
Joshua Chou ◽  
Bruce Milthorpe ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Marine Sponge ◽  
Adult Stem Cells ◽  
Cell Activation ◽  
Bone Growth ◽  
Early Stage ◽  
Organic Matrix ◽  
Evolutionary Relatedness ◽  
Organic Matrices

Use of ready-made marine skeletons is one of the simplest possible remedies to major problems hindering the future development of regenerative orthopaedics- such as, providing a richness of framework designs and now a potentially rich, accessible source of osteopromotive analogues and biomineralisation proteins. It has already been shown that coral and marine sponge skeletons can support self-sustaining musculoskeletal tissues and that extracts of spongin collagen and nacre seashell organic matrices promote bone mineralisation. This should not be surprising given that the pivotal biomineralisation proteins, which orchestrate bone morphogenesis are also found in the earliest calcifying marine organisms. This is because they are representatives of the first molecular components established for calcification, morphogenesis and wound healing. In support of this notion, it has emerged that BMP molecules- the main cluster of bone growth factors for human bone morphogenesis- are secreted by endodermal cells into the developing skeleton. In addition, the regenerative signalling proteins, TGF-b and Wnt-prime targets in bone therapeutics- are also present in early marine sponge development and instrumental to stem cell activation in Cnidarians. Based on this match between vertebrate and invertebrate main developmental proteins, we review the nature and extent of this evolutionary relatedness and use it to support the development of a new strategy, which is to mine selected marine origin organic matrices for novel metabolic, signalling and structural proteins/peptides and protein analogues to apply in regenerative orthopaedics, particularly when using adult stem cells. To support such a proposal we show early stage evidence-gathered in our own laboratory- of the presence of fibrinogen fragments and early osteopromotive effects of a coral organic matrix extract on stem cells. In practice the discovery of new osteopromotive and osteo-accelerant protein analogues will require use of traditional chromatography techniques, osteoactivity assays to hone in on potential proteins of significance and advanced proteomic tools to provide accurate sequencing, determine the mechanisms and molecular pathways involved in osteoactivation and determine the efficiency and effectiveness of marine skeleton-derived protein modulation of the stem cell (MSC) proteome. As more analogues are discovered using proteomic tools, skeletal organic matrices may have ever increasing utility for regenerative orthopaedics.

Sign in / Sign up

Export Citation Format

Share Document