Nucleation of Microbiologic Calcification by Proteolipid

Ennever, J.; Vogel, James J.; Rider, Linda J.; Boyan-Salyers, B.

doi:10.3181/00379727-152-39348

Cited by 38 publications

(16 citation statements)

References 6 publications

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“…Figure 1 shows the gel filtration profiles of crude phospholipid from the upper (A) and lower (B) growth centers of rachitic cartilage and the upper (C) and lower (D) growth centers of normal cartilage. These profiles are comparable with those of crude phospholipid from other calcifying tissues in that proteolipid elutes in the void volume [1,2,12]. There are apparent reproducible differences between the nonproteolipid 280 nm absorbing material of rachitic (A, B) and normal (C, D) cartilage phospholipids; that is, sharper definition of peaks in the normal tissue extracts, especially in the growth plate phospholipid.…”

Section: Methodssupporting

confidence: 59%

“…Films were compared with standards and/or indexed. The ability of the phospholipid extracts to initiate apatite formation was also ex- amined as a negative control since previous studies [1,2,12] have demonstrated that nonproteolipid phospholipid from bacteria and chick cartilage matrix vesicles fail to form apatite in this assay system. Figure 1 shows the gel filtration profiles of crude phospholipid from the upper (A) and lower (B) growth centers of rachitic cartilage and the upper (C) and lower (D) growth centers of normal cartilage.…”

Section: Methodsmentioning

confidence: 99%

“…Lipids were extracted using the procedure for calcifiable proteolipid isolation described by Ennever et al [12], modified for calcified tissues. Lyophilized samples were extracted with 200 ml chloroform: methanol 2:1 (v/v) for 24 h at 4~ and the extract separated from the residue by sequential filtrations through Whatman 50 hardened and Whatman GFA filters.…”

Section: Methodsmentioning

confidence: 99%

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Proteolipid-lipid relationships in normal and vitamin D-deficient chick cartilage

Boyan

Ritter

1984

Calcif Tissue Int

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Previous studies have shown that in vitro calcification of chick epiphyseal cartilage matrix vesicles is proteolipid-dependent. The purpose of this research is to examine the role of proteolipid in cartilage calcification in vivo by comparing the proteolipid concentration of normal and vitamin D-deficient chick epiphyseal cartilage, the relationship of proteolipid to other tissue lipids, and its ability to support in vitro apatite formation. Proteolipid was isolated from the upper growth centers (reserve cell zone, upper proliferative zone) and lower growth centers (lower proliferative, hypertrophic, and calcified cartilage zones) of long-bone epiphyses from 3-week-old normal and rachitic male white leghorn chicks by Sephadex LH-20 chromatography of the crude phospholipid component of the total lipid extract. In both normal and rachitic tissue the proteolipid/dry weight and proteolipid/total lipid ratios were greater in the lower growth center than in the upper zones. No statistically significant change in the proteolipid/total lipid ratio in rachitic tissues relative to comparable cell zones in normal cartilages was observed. However, there was an increase in the nonproteolipid phospholipid content of rachitic tissues, altering the relative proteolipid/phospholipid composition. Whereas proteolipids from normal tissue supported in vitro calcification, proteolipids from rachitic tissues did not, indicating a direct effect of vitamin D on proteolipid structure. These data support the hypothesis that failure of rachitic cartilage to calcify in vivo may be due in part to alterations in phospholipid and proteolipid metabolism.

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Section: Methodssupporting

confidence: 59%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Proteolipid-lipid relationships in normal and vitamin D-deficient chick cartilage

Boyan

Ritter

1984

Calcif Tissue Int

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“…Phthalic acid demineralization does alter the distribution of proteolipid apoprotein in the Sephadex LH-20 eluates of crude phospholipid from the distribution normally observed for formic acid demineralized cells [2] or cells extracted sequentially with neutral and acidified chloroform:methanol [9]. In the latter instances, calcifiable proteolipid is present in fraction II; only minute amounts of apoprotein are present in fractions III or IV.…”

Section: Discussionmentioning

confidence: 90%

“…Following recalcification of the lipid extracts, the greatest percentage of CPLX was found in the proteolipid acidic phospholipid component. However, when mineral was precipitated in the presence of the nonproteolipid phospholipid extract, which does not calcify in vitro [2], virtually no CPLX was present, suggesting that the proteolipid apoprotein creates a particular phospholipid environment conducive to both CPLX and mineral formation. Since proteolipids and CPLX have been associated with membrane-initiated calcification, it is important to determine whether their apparent relationship in vitro is valid in vivo.…”

mentioning

confidence: 99%

Co-isolation of proteolipids and calcium-phospholipid-phosphate complexes

Boyan

Boskey

1984

Calcif Tissue Int

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This study demonstrates that calcium-phospholipid-phosphate complexes (CPLX) and calcifiable proteolipid are associated in vivo by establishing that they can be co-isolated from calcified bacteria. Both of these membrane constituents, which support apatite formation in vitro, have been isolated independently from Bacterionema matruchotii. However, isolation of proteolipid was preceded by demineralization in 2N formic acid, thereby dissociating bound Ca, whereas isolation of CPLX included sonication of calcified bacteria in 2:1:1.5 chloroform:methanol:Tris buffer, thereby dissociating any protein. Co-isolation is possible by demineralizing the calcified bacteria with 50 mM phthalic acid, pH 5.5, followed by extraction with 2:1 chloroform:methanol, and precipitation of crude phospholipid with acetone. CPLX and proteolipid are present in all Sephadex LH-20 chromatographic fractions of the crude phospholipid and of diethyl ether precipitates of the crude phospholipid. CPLXs contain protein:phospholipid:Ca:Pi but differ in relative composition from each other and from independently isolated CPLX. The Ca:phospholipid:Pi molar ratio of diethyl ether precipitable proteolipid-CPLX is most similar to previously published values for CPLX. The protein content of CPLX accounts for all of the proteolipid apoprotein in each Sephadex LH-20 fraction.

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