Silicon in Biological Material. I. Determinations Eliminating Silicon as a Contaminant

McGavack, Thomas H.; Leslie, James G.; Kao, Kung-Ying Tang

doi:10.3181/00379727-110-27469

Cited by 11 publications

(2 citation statements)

References 3 publications

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“…During attempts to identify the binding site of Si we discovered that certain glycosaminoglyeans, * Reported Si amounts vary greatly, depending on the analytical methods used. A large number of results (9, 10) obtained before development of suitable methods (11,12) and the advent of plastic laboratory ware are much higher than those found more recently (8,13 …”

Section: Introductionmentioning

confidence: 89%

A Bound Form of Silicon in Glycosaminoglycans and Polyuronides

Schwarz

1973

Proc. Natl. Acad. Sci. U.S.A.

298

121

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Silicon was found to be a constituent of certain glycosaminoglycans and polyuronides, where it occurs firmly bound to the polysaccharide matrix. 330-554 ppm of bound Si were detected in purified hyaluronic acid from umbilical cord, chondroitin 4-sulfate, dermatan sulfate, and heparan sulfate. These amounts correspond to 1 atom of Si per 50,000-85,000 molecular weight or 130-280 repeating units. 57-191 Silicon (Si) is essential for growth and general development (1). In all-plastic isolators that exclude the element from the environment (2, 3), growth of rats is reduced by 30-35% when Si-deficient aminoacid diets are fed, and bone deformations develop. Dietary supplements of silicate prevent these symptoms. Similar findings have been reported for chicks (4). Si, moreover, is needed in rats for normal pigment formation in the enamel of incisors (5).Even though it has been known for years that Si occurs in small, varying amounts in all animals, very little concrete evidence exists about its functional significance and biochemical behavior (6, 7). In mammals, Si occurs most abundantly in connective tissue and related structures. While amounts in blood and parenchymal organs are relatively low, the Si content of skin, cartilage, ligaments, and other tissues of mainly mesodermal origin frequently exceeds 100 ,g/g dry wt (8)*.In extensive experiments with cartilage and bovine-nasal septum we found Si to be strongly bound -to the organic matrix of these tissues. During attempts to identify the binding site of Si we discovered that certain glycosaminoglyeans, * Reported Si amounts vary greatly, depending on the analytical methods used. A large number of results (9, 10) obtained before development of suitable methods (11,12) and the advent of plastic laboratory ware are much higher than those found more recently (8,13

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Section: Introductionmentioning

confidence: 89%

A Bound Form of Silicon in Glycosaminoglycans and Polyuronides

Schwarz

1973

Proc. Natl. Acad. Sci. U.S.A.

298

121

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“…All media (6 ml each) were recovered and centrifuged at 10,000 g at room temperature. Soluble silicate concentration was measured on 100 μl of the cleared medium by a Silicate Kit (Merck, Sharp and Dohme SpA, Rome, Italy), quantifying the silicic acid through the ammonium molybdate colorimetric method (McGavack et al, 1962), according to the manufacturer's instructions.…”

Section: Soluble Silicate Assaymentioning

confidence: 99%

Silica-induced fibrosis: an ancient response from the early metazoans

Pozzolini

Scarfı̀

Gallus

et al. 2017

Journal of Experimental Biology

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Exposure to crystalline silica particles causes silicosis, an occupational disease leading to an overproduction of collagen in the lung. The first step of this pathology is characterized by the release of inflammatory mediators. Tumour necrosis factor (TNF) is a pro-inflammatory cytokine directly involved in silica-induced pulmonary fibrosis. The marine demosponge is able to incorporate silica grains and partially dissolve the crystalline forms apparently without toxic effects. In the present work, tissue explants were treated with fine quartz dust and the expression level of fibrogenic genes was assayed by qPCR, demonstrating an overexpression of a fibrillar and a non-fibrillar collagen and of prolyl-4-hydroxylase enzyme. The deposition of new collagen could also be documented in quartz-treated sponge explants. Furthermore, TNF pro-inflammatory cytokine overexpression and involvement in silica-induced sponge collagen biosynthesis was demonstrated in quartz-treated explants as compared with controls by means of specific TNF inhibitors affecting the fibrogenic gene response. As no documentable detrimental effect was observed in treated explants, we conclude that the unique quartz engulfment and erosion is physiological and beneficial to the animal, leading to new collagen synthesis and strengthening of the body stiffness. Thus, we put forward the hypothesis that an ancient physiological behaviour from the lowest of the Metazoa, persisting through evolution via the same molecular mediators such as TNF, may have become the cause of disease in the specialized tissues of higher animals such as mammals.

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Determination of the silicon content of food

Bowen

Peggs

1984

J Sci Food Agric

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The determination of silicon in biological material was investigated using solution absorption spectrometry (SAS) and atomic absorption spectrometry (AAS). Most analytical reagents and ion-free waters contain enough silicon to cause high blanks, and require purification. Glassware and silica ware should not be used. Standard silica solutions do not polymerise in a week if the silicon concentration is below 100mglitre-'. Biological materials were dry-ashed and then fused with pure sodium tetraborate before dissolution in dilute nitric acid. Phosphates interfere with SAS if the P:Si ratio exceeds 5 : l but can be removed by precipitation. They interfere somewhat less with AAS if the P: Si ratio exceeds 20: 1. Borates, calcium, potassium and sodium do not interfere with AAS at ratios B : Si = 500 : 1, Ca : Si = 200 : 1, K : Si = 100 : 1, Na : Si = 1000 : 1. Determinations of silicon in foods by both methods agreed, and barley and oats were found to have a high silicon content. The average British diet is estimated to contain 31mg silicon day-'.

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Silicon in Biological Material. I. Determinations Eliminating Silicon as a Contaminant

Cited by 11 publications

References 3 publications

A Bound Form of Silicon in Glycosaminoglycans and Polyuronides

A Bound Form of Silicon in Glycosaminoglycans and Polyuronides

Silica-induced fibrosis: an ancient response from the early metazoans

Determination of the silicon content of food

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