Adenine nucleotide levels and adenosine metabolism in cultured calvarial bone

1984 ◽  
Vol 120 (4) ◽  
pp. 551-555 ◽  
Author(s):  
BERTIL B. FREDHOLM ◽  
ULF LERNER
Keyword(s):  
Adenine Nucleotide ◽  
Calvarial Bone

Structure of contact sites between the outer and inner mitochondrial membranes investigated by HVEM tomography

1996 ◽  
Vol 54 ◽  
pp. 966-967
Author(s):  
C.A. Mannella ◽  
K.F. Buttle ◽  
K.A. O‘Farrell ◽  
A. Leith ◽  
M. Marko
Keyword(s):  
Liver Mitochondrion ◽  
Adenine Nucleotide ◽  
Protein Complexes ◽  
Mitochondrial Membranes ◽  
Electron Microscopic ◽  
Contact Sites ◽  
Transmission Electron ◽  
Precursor Proteins ◽  
Membrane Contacts ◽  
And Function

Early transmission electron microscopy of plastic-embedded, thin-sectioned mitochondria indicated that there are numerous junctions between the outer and inner membranes of this organelle. More recent studies have suggested that the mitochondrial membrane contacts may be the site of protein complexes engaged in specialized functions, e.g., import of mitochondrial precursor proteins, adenine nucleotide channeling, and even intermembrane signalling. It has been suggested that the intermembrane contacts may be sites of membrane fusion involving non-bilayer lipid domains in the two membranes. However, despite growing interest in the nature and function of intramitochondrial contact sites, little is known about their structure.We are using electron microscopic tomography with the Albany HVEM to determine the internal organization of mitochondria. We have reconstructed a 0.6-μm section through an isolated, plasticembedded rat-liver mitochondrion by combining 123 projections collected by tilting (+/- 70°) around two perpendicular tilt axes. The resulting 3-D image has confirmed the basic inner-membrane organization inferred from lower-resolution reconstructions obtained from single-axis tomography.

The Platelet of the Newborn Infant – Adenine Nucleotide Metabolism and Release

1980 ◽  
Vol 43 (02) ◽  
pp. 099-103 ◽  
Author(s):  
J M Whaun ◽  
P Lievaart ◽  
Keyword(s):  
Newborn Infant ◽  
Adenine Nucleotide ◽  
Platelet Rich Plasma ◽  
Adenine Nucleotides ◽  
Newborn Infants ◽  
Specific Radioactivity ◽  
Nucleotide Metabolism ◽  
Breakdown Product ◽  
Term Infants ◽  
Adenine Nucleotide Metabolism

SummaryBlood from normal full term infants, mothers and normal adults was collected in citrate. Citrated platelet-rich plasma was prelabelled with 3H-adenine and reacted with release inducers, collagen and adrenaline. Adenine nucleotide metabolism, total adenine nucleotide levels and changes in sizes of these pools were determined in platelets from these three groups of subjects.At rest, the platelet of the newborn infant, compared to that of the mother and normal adult, possessed similar amounts of adenosine triphosphate (ATP), 4.6 ± 0.2 (SD), 5.0 ± 1.1, 4.9 ± 0.6 µmoles ATP/1011 platelets respectively, and adenosine diphosphate (ADP), 2.4 ± 0.7, 2.8 ± 0.6, 3.0 ± 0.3 umoles ADP/1011 platelets respectively. However the marked elevation of specific radioactivity of ADP and ATP in these resting platelets indicated the platelet of the neonate has decreased adenine nucleotide stores.In addition to these decreased stores of adenine nucleotides, infant platelets showed significantly impaired release of ADP and ATP on exposure to collagen. The release of ADP in infants, mothers, and other adults was 0.9 ± 0.5 (SD), 1.5 ± 0.5, 1.5 ± 0.1 umoles/1011 platelets respectively; that of ATP was 0.6 ± 0.3, 1.0 ± 0.1,1.3 ± 0.2 µmoles/1011 platelets respectively. With collagen-induced release, platelets of newborn infants compared to those of other subjects showed only slight increased specific radioactivities of adenine nucleotides over basal levels. The content of metabolic hypoxanthine, a breakdown product of adenine nucleotides, increased in both platelets and plasma in all subjects studied.In contrast, with adrenaline as release inducer, the platelets of the newborn infant showed no adenine nucleotide release, no change in total ATP and level of radioactive hypoxanthine, and minimal change in total ADP. The reason for this decreased adrenaline reactivity of infant platelets compared to reactivity of adult platelets is unknown.Infant platelets may have different membranes, with resulting differences in regulation of cellular processes, or alternatively, may be refractory to catecholamines because of elevated levels of circulating catecholamines in the newborn period.

In vivo Evaluation of a Collagen Scaffold Preconditioned with Adipose-derived Mesenchymal Stem Cells Used for Bone Regeneration A histological study

2018 ◽  
Vol 55 (4) ◽  
pp. 691-695
Author(s):  
Tudor Sorin Pop ◽  
Anca Maria Pop ◽  
Alina Dia Trambitas Miron ◽  
Klara Brinzaniuc ◽  
Simona Gurzu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Bone Regeneration ◽  
Histological Study ◽  
Collagen Scaffold ◽  
Bone Defects ◽  
Collagen Scaffolds ◽  
In Vivo Evaluation ◽  
Calvarial Bone ◽  
Bone Apposition

The use of collagen scaffolds and stem cells for obtaining a tissue-engineering complex has been an important concept in promoting repair and regeneration of the bone tissue. Such units represent important steps in the development of an ideal scaffold-cell complex that would sustain new bone apposition. The aim of our study was to perform a histologic evaluation of the healing of critical-sized bone defects, using a biologic collagen scaffold with adipose-derived mesenchymal stem cells, in comparison to negative controls created in the adjacent bone. We used 16 Wistar rats and according to the study design 2 calvarial bone defects were created in each animal, one was filled with collagen seeded with adipose-derived stem cells and the other one was considered negative control. During the following month, at weekly intervals, the animals were euthanized and the specimens from bone defects were histologically evaluated. The results showed that these scaffolds were highly biocompatible as only moderate inflammation no rejection reactions were observed. Furthermore, the first signs of osseous healing appeared after two weeks accompanied by angiogenesis. Collagen scaffolds seeded with adipose-derived mesenchymal stem cells can be considered a promising treatment option in bone regeneration of large defects.

Regeneration of Bone Defects Using Bioactive Glass Combined with Adipose-derived Mesenchymal Stem Cells. An experimental in vivo study

2019 ◽  
Vol 70 (6) ◽  
pp. 1983-1987
Author(s):  
Cristian Trambitas ◽  
Anca Maria Pop ◽  
Alina Dia Trambitas Miron ◽  
Dorin Constantin Dorobantu ◽  
Flaviu Tabaran ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Bioactive Glass ◽  
Bone Repair ◽  
Bone Defects ◽  
Calvarial Bone ◽  
Specific Protocol ◽  
Repair Mechanisms ◽  
Male Wistar Rats

Large bone defects are a medical concern as these are often unable to heal spontaneously, based on the host bone repair mechanisms. In their treatment, bone tissue engineering techniques represent a promising approach by providing a guide for osseous regeneration. As bioactive glasses proved to have osteoconductive and osteoinductive properties, the aim of our study was to evaluate by histologic examination, the differences in the healing of critical-sized calvarial bone defects filled with bioactive glass combined with adipose-derived mesenchymal stem cells, compared to negative controls. We used 16 male Wistar rats subjected to a specific protocol based on which 2 calvarial bone defects were created in each animal, one was filled with Bon Alive S53P4 bioactive glass and adipose-derived stem cells and the other one was considered control. At intervals of one week during the following month, the animals were euthanized and the specimens from bone defects were histologically examined and compared. The results showed that this biomaterial was biocompatible and the first signs of osseous healing appeared in the third week. Bone Alive S53P4 bioactive glass could be an excellent bone substitute, reducing the need of bone grafts.

P1, P5-Bis-(5′-adenosyl)pentaphosphate: Is this Adenylate Kinase Inhibitor Substrate for Mitochondrial Processes?

1977 ◽  
Vol 32 (9-10) ◽  
pp. 786-791 ◽  
Author(s):  
Josef Köhrle ◽  
Joachim Lüstorff ◽  
Eckhard Schlimme
Keyword(s):  
Adenylate Kinase ◽  
Kinase Inhibitor ◽  
Adenine Nucleotide ◽  
Nucleoside Diphosphate Kinase ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Rat Liver Mitochondria ◽  
Intermembrane Space ◽  
Rabbit Muscle ◽  
Inner Mitochondrial Membrane

Abstract 1. P1, P5-Bis-(5′-adenosyl)pentaphosphate (Ap5A) inhibits “soluble” adenylate kinase even when this enzyme is an integral part of the complete mitochondrion. The Ki is 10-5м , i. e. about two orders of magnitude higher than the inhibitor constants determined for the purified adenylate kinase of rabbit muscle and an enzyme preparation separated from the mitochondrial intermembrane space. The weaker inhibitory effect is due to a lower accessibility of the enzyme.2. As to be expected Ap5A which is of the “multisubstrate analogue”-type does not affect mito­ chondrial nucleoside diphosphate kinase.3. Though Ap5A owns the structural elements of both ATP and ADP it is not a substrate of the adenine nucleotide carrier, i.e. neither it is exchanged across the inner mitochondrial membrane nor specifically bound.4. Ap5A is not metabolized by rat liver mitochondria.

scholarly journals A convolution based computational approach towards DNA N6-methyladenine site identification and motif extraction in rice genome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chowdhury Rafeed Rahman ◽  
Ruhul Amin ◽  
Swakkhar Shatabda ◽  
Md. Sadrul Islam Toaha
Keyword(s):  
Operating Characteristic ◽  
Adenine Nucleotide ◽  
Characteristic Curve ◽  
Rice Genome ◽  
Plant Genome ◽  
Feature Importance ◽  
Importance Analysis ◽  
Motif Extraction ◽  
Site Identification ◽  
By Products

AbstractDNA N6-methylation (6mA) in Adenine nucleotide is a post replication modification responsible for many biological functions. Automated and accurate computational methods can help to identify 6mA sites in long genomes saving significant time and money. Our study develops a convolutional neural network (CNN) based tool i6mA-CNN capable of identifying 6mA sites in the rice genome. Our model coordinates among multiple types of features such as PseAAC (Pseudo Amino Acid Composition) inspired customized feature vector, multiple one hot representations and dinucleotide physicochemical properties. It achieves auROC (area under Receiver Operating Characteristic curve) score of 0.98 with an overall accuracy of 93.97% using fivefold cross validation on benchmark dataset. Finally, we evaluate our model on three other plant genome 6mA site identification test datasets. Results suggest that our proposed tool is able to generalize its ability of 6mA site identification on plant genomes irrespective of plant species. An algorithm for potential motif extraction and a feature importance analysis procedure are two by products of this research. Web tool for this research can be found at: https://cutt.ly/dgp3QTR.

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