Collagen Formation and Fibrogenesis with Special Reference to the Role of Ascorbic Acid

1963 ◽  
pp. 301-361 ◽  
Author(s):  
Bernard S. Gould
Keyword(s):  
Ascorbic Acid ◽  
Special Reference ◽  
Collagen Formation

Cellular functions of ascorbic acid

1990 ◽  
Vol 68 (10) ◽  
pp. 1166-1173 ◽  
Author(s):  
Harish Padh
Keyword(s):  
Ascorbic Acid ◽  
Reduced Form ◽  
Enzymatic Reactions ◽  
Cellular Functions ◽  
Animal Cells ◽  
Major Function ◽  
Collagen Formation ◽  
Oxidative Products ◽  
Catalytic Cycles

It has long been suspected that ascorbic acid is involved in many cellular reactions. This is evident from the multitude of seemingly unrelated symptoms seen in scurvy. However, until recently, our understanding of its involvement was confined to its role in the synthesis of collagen. Studies in the past few years have unveiled mechanisms of its actions in collagen formation and many other enzymatic reactions. In addition, numerous physiological responses are reportedly affected by ascorbic acid. From the well-characterized enzymatic reactions involving ascorbic acid, it has become clear that in animal cells the ascorbate does not seem to be directly involved in catalytic cycles. Rather its major function seems to keep prosthetic metal ions in their reduced form. The role of ascorbate as a reductant in these enzymatic reactions complements its other antioxidant functions which have been recently appreciated, including that as a scavenger of free radicals. Therefore, it seems that the major function of ascorbate is to protect tissues from harmful oxidative products and to keep certain enzymes in their required reduced forms. However, it remains unclear how the deficiency of ascorbate leads to the pathological symptoms found in scurvy.Key words: ascorbic acid, vitamin C, biochemical functions, antioxidant, recommended dietary allowances, hydroxylation.

Wound Contraction in Relation to Collagen Formation in Scorbutic Guinea-pigs

Development ◽  
1956 ◽  
Vol 4 (2) ◽  
pp. 167-175
Author(s):  
M. Abercrombie ◽  
M. H. Flint ◽  
D. W. James
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pigs ◽  
Wound Contraction ◽  
Skin Wounds ◽  
Collagen Fibres ◽  
Collagen Formation ◽  
Effective Force ◽  
Mobile Part ◽  
Centripetal Movement

A Wound in any mobile part of the skin of a mammal diminishes in area as it heals by a centripetal movement of the undamaged skin surrounding it. This movement, usually called wound contraction, depends on a pull exerted by the material within the wound (Lindquist, 1946; Abercrombie, Flint, & James, 1954; Billingham & Medawar, 1955). It is commonly believed that the effective force is developed by the newly formed collagen fibres. In a previous paper, however (Abercrombie, Flint, & James, 1954), we found that the course of the contraction of skin wounds in rats did not parallel the deposition of new collagen, chemically measured. This result, while certainly in no way conclusive by itself, suggested that the supposed role of collagen in contraction ought to be tested more stringently. This we have now done by measuring wounds made on guinea-pigs receiving a diet devoid of ascorbic acid.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

Ambivalent role of ascorbic acid in the metal-catalyzed oxidation of oligopeptides

2021 ◽  
pp. 111510
Author(s):  
Nikolett Bodnár ◽  
Katalin Várnagy ◽  
Lajos Nagy ◽  
Gizella Csire ◽  
Csilla Kállay
Keyword(s):  
Ascorbic Acid ◽  
Metal Catalyzed Oxidation ◽  
Metal Catalyzed ◽  
Catalyzed Oxidation

scholarly journals The role of ascorbic acid combined exposure on Imidacloprid-induced oxidative stress and genotoxicity in Nile tilapia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Islam M. El-Garawani ◽  
Elsayed A. Khallaf ◽  
Alaa A. Alne-na-ei ◽  
Rehab G. Elgendy ◽  
Gaber A. M. Mersal ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ascorbic Acid ◽  
Nile Tilapia ◽  
Protective Agent ◽  
Strand Breaks ◽  
Gill Cells ◽  
Significant Amelioration ◽  
Neonicotinoid Insecticide ◽  
Dna Strand

AbstractImidacloprid (Imid), a systemic neonicotinoid insecticide, is broadly used worldwide. It is reported to contaminate aquatic systems. This study was proposed to evaluate oxidative stress and genotoxicity of Imid on Nile tilapia (Oreochromis niloticus) and the protective effect of ascorbic acid (Asc). O. niloticus juveniles (30.4 ± 9.3 g, 11.9 ± 1.3 cm) were divided into six groups (n = 10/replicate). For 21 days, two groups were exposed to sub-lethal concentrations of Imid (8.75 ppm, 1/20 of 72 h-LC50 and 17.5 ppm, 1/10 of 72 h-LC50); other two groups were exposed to Asc (50 ppm) in combination with Imid (8.75 and 17.5 ppm); one group was exposed to Asc (50 ppm) in addition to a group of unexposed fish which served as controls. Oxidative stress was assessed in the liver where the level of enzymatic activities including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in addition to mRNA transcripts and, Lipid peroxidation (LPO) were evaluated. Moreover, mitotic index (MI) and comet assay were performed, in addition, the erythrocytic micronucleus (MN), and nuclear abnormalities (NA) were observed to assess genotoxicity in fish. Imid exposure induced significant (p ˂ 0.05) changes in the antioxidant profile of the juveniles' liver by increasing the activities and gene expression of SOD, CAT and GPX as well as elevating the levels of LPO. DNA strand breaks in gill cells, erythrocytes and hepatocytes along with erythrocytic MN and NA were also significantly elevated in Imid-exposed groups. MI showed a significant (p ˂ 0.05) decrease associated with Imid exposure. Asc administration induced a significant amelioration towards the Imid toxicity (8.75 and 17.5 ppm). A significant protective potency against the genotoxic effects of Imid was evidenced in Asc co-treated groups. Collectively, results highlight the importance of Asc as a protective agent against Imid-induced oxidative stress and genotoxicity in O. niloticus juveniles.

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