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J Ennever

Publications and source records attributed to J Ennever.

At least 19 recordsLinked to original sources
PubMed1988

Ageing-associated thiol loss in Bacterionema matruchotii.

This work tested the concept that thiol loss, proposed as a cause of animal ageing, occurs in ageing cultures of Bacterionema matruchotii. Paired comparisons were made between thiol levels of exponential- and stationary-phase cultures. Values for stationary phase were consistently and significantly (P less than 0.01) lower. If bacterial thiol loss is an effect of culture ageing rather than a cause, the same possibility must be considered with respect to tissue. However, if thiol loss is a cause of ageing, the role for thiol loss in tissue ageing would be strengthened. A major problem in the biology of ageing is to distinguish between cause and consequence. Bacterial culture could provide a relatively simple model for such inquiry.

Actinomycetaceae↗
PubMed1984

Proteolipid and human aorta calcification, in vitro.

The objective of this study was to determine whether in vitro calcification of human aorta is proteolipid dependent. Homogenates were prepared from tissue with no gross pathologic manifestations. Samples were examined for calcifiability in a metastable calcium phosphate solution before and after lipid extraction. Fractions of the extracted lipid were similarly examined. The tissue calcified before but not after lipid extraction. Calcifiability was restricted to the proteolipid portion of the lipid extract. Under the conditions employed, therefore, proteolipid is required for calcification of human aorta, in vitro.

Amino Acids↗
PubMed1984

Proteolipid and collagen calcification, in vitro.

Initiation of in vitro calcification with insoluble type I collagen appears to be a function of tightly-bound proteolipid. The collagen preparation calcified during incubation in a metastable calcium phosphate solution before but not after lipid extraction. Calcifiability of the extracted lipid, similarly incubated, was restricted to the proteolipid fraction.

Amino Acids↗
PubMed1983

Proteolipid and bovine aorta calcification, in vitro.

Proteolipid was examined for nucleation of bovine aorta calcification. Tissue homogenates were tested for in vitro calcifiability before and after lipid extraction followed by similar tests of the extract and its fractions. The tissue calcified before but not after lipid extraction. Of the lipid fractions, only proteolipid calcified. Within the constraints imposed, proteolipid is required for initiation of bovine aorta calcification, in vitro.

Animals↗
PubMed1981

Magnesium inhibition of apatite nucleation by proteolipid.

The effect of magnesium on apatite nucleation by Bacterionema matruchotii proteolipid was determined. The ion, in metastable calcium phosphate solution at a concentration that did not reduce proteolipid calcium binding, prevented apatite crystallization. The data were compared with those involving magnesium and homogenous nucleation of apatite in vitro.

Actinomycetaceae↗
PubMed1981

Calcifiability comparison among selected microorganisms.

Seven ATCC strains of bacteria were examined for apatite formation in a chemically-defined calcification-supporting medium and also in a metastable calcium phosphate solution. One, E. coli, calcified in both. One, S. aureus, calcified in the solution, but not in the medium. The other five did not calcify in either. The results substantiate the belief that calcification is restricted to certain microorganisms. However, they do not rule out the possibility that a noncalcifiable microorganism has the potential to calcify, and the activity is prevented by a cell component. Additionally, the findings emphasize that determining microbiologic calcifiability only in a calcification-supporting culture medium is inadequate. In culture, an efficient calcium pump might preclude calcification by establishing a cytoplasmic calcium level too low for nucleation activation. Calcifiability assays should be done by incubating minimally-metabolizing freeze-dried cells in metastable calcium phosphate solution.

Apatites↗
PubMed1980

Calcification by proteolipid from atherosclerotic aorta.

Calcified atherosclerotic aorta was examined for proteolipid capable of nucleating apatite, the crystal species of aortic calcification. Appropriate tissue pieces were decalcified with dilute formic acid and extracted with chloroform-methanol. Lipid fractionation yielded proteolipid which, upon incubation in metastable calcium phosphate solution, induced apatite crystallization. The proteolipid was partially characterized as a hydrophobic protein, acidic phospholipid complex. It resembles the nucleator previously demonstrated for bone matrix calcification.

Aorta↗
PubMed1980

Influence of alkaline pH on the effectiveness of sodium fluoride dentifrices.

Two similar sodium fluoride dentifrices, one neutral and one alkaline, were compared to a placebo for clinical effectiveness in reducing caries. The neutral dentifrice contained 35% less soluble fluoride than the alkaline dentifrice. Both fluoride dentifrices were significantly effective but were not different from each other.

Child↗
PubMed1979

Characterization of calculus matrix calcification nucleator.

The nucleator of dental calculus matrix calcification, in vitro, was analyzed. Attention focused on proteolipid singularity, amino acid composition and related polarity, and phospholipid components. The data were compared to those of the nucleator of Bacterionema matruchotii calcification.

Actinomycetaceae↗
PubMed1978

Pre-apatitic mineral deposition in Bacterionema matruchotii.

A preliminary examination of calcification of Bacterionema matruchotii was undertaken to provide a base-line for future kinetic and mechanistic studies. Specific ion ratios were correlated with crystallography and ultrastructure. Observations include: three consistent X-ray diffraction patterns; no resolution of cellular EMP by electron microscopy; increasing Ca/Mg, Ca/P during calcification.

Actinomycetaceae↗
PubMed1978

Characterization of Bacterionema matruchotii calcification nucleator.

The nucleator of Bacterionema matruchotii calcification was characterized. Parameters examined were: proteolipid purity and singularity, amino acid composition and relative polarity, phospholipid composition, apoprotein homogeneity, essentiality of the complex for nucleation, and ordered structure. The data fulfill a requirement for comparisons among apatite-nucleating proteolipids.

Actinomycetaceae↗
PubMed1977

Proteolipid and calculus matrix calcification in vitro.

The initiator of calculus matrix calcification, in vitro, was isolated. Crude phospholipid, known to contain the factor, was separated into five fractions by column chromatography. A single protein-containing fraction induced apatite formation during incubation. The nucleating fraction was indentified as a proteolipid.

Actinomycetaceae↗
PubMed1977

Proteolipid and bone matrix calcification in vitro.

Proteolipid was demonstrated to contain the nucleator of bone matrix calcification, in vitro. Crude phospholipid extracted from bone matrix was fractionated by gel filtration. A single, protein-containing fraction induced apatite crystallization in a metastable calcium phosphate solution. The fraction was identified as proteolipid. The result supports the validity of a microbiologic analogue for vertebrate calcification.

Actinomyces↗
PubMed1976

Nucleation of microbiologic calcification by proteolipid.

The component of crude phospholipid responsible for B. matruchotii calcification was isolated. Crude phospholipid, extracted from the microorganism, was separated into five fractions by column chromatography. A single, protein-containing fraction catalyzed apatite formation in a metastable calcium phosphate solution. The nucleating fraction was identified as a proteolipid.

Actinomycetaceae↗
PubMed1975

Calcification by Candida albicans.

Candida albicans was grown in a chamically defined medium in which certain microorganisms are known to calcify. The fungus developed calcium phosphate deposits with the same X-ray diffraction maxima as biological apatite.

Apatites↗