Publications

the evolution of histones in relationship to recent advances in elucidating chromatin structure.		1979	555823
diphytanyl and dibiphytanyl glycerol ether lipids of methanogenic archaebacteria.	the lipids of nine different methanogenic bacterial strains are comprised of diphytanyl glycerol diethers, previously known only in extremely halophilic bacterial, as well as dibiphytanyl diglycerol tetraethers, known formerly only in the extremely thermoacidophilic bacteria thermoplasma and sulfolobus. of the methanogens examined from four representative taxonomic groups, methanobacterium and methanospirillum contained both types of isopranyl ethers in nearly equal proportions, whereas the cocc ...	1979	758677
physiologically important stabilization of dna by a prokaryotic histone-like protein.	the thermophilic mycoplasma thermoplasma acidophilum has tightly bound to its dna a protein that closely resembles the histones of eukaryotes. dna associated with this protein is more stable than free dna against thermal denaturation by about 40 degrees c, as shown in both native nucleoprotein and in hybrid nucleoprotein reconstituted in vitro with calf dna. since only about 20 percent of the dna in this organism is associated with the histone-like protein, we suggest that its physiological func ...	1978	694528
a restriction enzyme tha i from the thermophilic mycoplasma thermoplasma acidophilum.	a type ii restriction enzyme (tha i) has been isolated from the thermophilic mycoplasma thermoplasma acidophilum. a new method of general application was used to determine the dna sequence cleaved by the enzyme. tha i cuts dna in the centre of the sequence cgcg. single-stranded dna is not a substrate. tha i does not cut t. acidophilum dna which is presumably modified. this is the first description of a restriction enzyme from a mycoplasma. because tha i is easily prepared in large amounts of app ...	1978	673834
phylogenetic affinities between eukaryotic cells and a thermophilic mycoplasma.	thermoplasma acidophilum, a thermophilic mycoplasma, has several unusual features suggesting a possible relationship to eukaryotic cells. one feature is a histone-like protein that is associated with the dna, condensing it into subunits similar to those in eukaryotic chromatin. a second feature is an association of cytoplasmic proteins that resembles eukaryotic actin and myosin. these two components are widely distributed in different groups of eukaryotic cells, but are typically lacking in prok ...	1978	656568
the effect of a13+ on the physical properties of membrane lipids in thermoplasma acidophilum.		1978	215137
ultrastructural localization of thermoplasma acidophilum surface carbohydrate by using concanavalin a.	surface carbohydrate, presumably the lipopolysaccharide, of thermoplasma acidophilum was visualized by means of the concanavalin a, horseradish peroxidase, and diaminobenzidine cytochemical staining procedure.	1978	641014
zeta-potential and surface charge of thermoplasma acidophila.	the surface charge density and the zeta-potential of thermoplasma acidophila was estimated from microscopic electrophoresis experiments. the cells moved towards the positive electrode. the mobility remained constant from ph 2 to 5, and increased for ph values higher than 6. the mobility at ph 6 decreased dramatically with increased external ca2+ concentration. at ph 2 and an ionic strength similar to that of the growth medium, the zeta-potential was about 8 mv, negative relative to the bulk medi ...	1977	18171
membrane potential of thermoplasma acidophila.		1977	14021
lipoquinones of some bacteria and mycoplasmas, with considerations on their functional significance.	in a comparative study the lipoquinones of some chemoorganotrophic, facultatively aerobic bacteria, and representative acholeplasma, mycoplasma, spiroplasma, and thermoplasma strains were investigated. the quinones were partly purified by preparative thin layer chromatography of lipid extracts, and characterized by their difference spectra (reduced minus oxidized) and rf values. respiring bacteria expectedly contained benzoquinones and/or naphthoquinones in micromolar concentrations whereas some ...	1977	413478
long-chain diglycerol tetraethers from thermoplasma acidophilum.	the c40 isopranol-containing glycerol ether residues which characterize the complex lipids of the extreme thermoacidophile thermoplasma acidophilum were isolated and purified from the glycolipid and phospholipid fractions. the glycerol ether, as well as the acetate and methoxy derivatives were characterized by thin-layer, gel-permeation and gas-liquid chromatography, infrared, nuclear magnetic resonance and mass spectrometry and by vapor phase osmometry. the glycerol ethers are proposed to be un ...	1977	857900
thermoplasma acidophilum: intracellular ph and potassium concentration.	thermoplasma acidophilum is a free-living thermophilic mycoplasma. although the organism lacks a cell wall, it can grow in medium as dilute as 66 mosm. the intracellular k+ concentration can be as low as 17 mm, but varies according to the osmolality of the culture medium. the internal ph can be measured by taking advantage of the fact that t. acidophilum undergoes lysis when the ph is adjusted to neutrality. thus, by appropriate analysis of titration curves, it is possible to conclude that the i ...	1976	12804
distribution and composition of lipopolysaccharides from mycoplasmas.	polymeric carbohydrates containing glycerol and fatty acids were isolated from whole cells and membranes of mycoplasmas by hot aqueous phenol extraction and gel filtration. lipopolysaccharides were found to occur in four species of acholeplasma, two of anaeroplasma, and in mycoplasma neurolyticum. none were detected in spiroplasma citri or in five species of mycoplasma. all lipopolysaccharides contained both neutral and n-acylated amino sugars in ratios varying from 1:1 to 3:1. the neutral sugar ...	1976	1254559
histone-like protein in the prokaryote thermoplasma acidophilum.	the dna of the prokaryote thermoplasma acidophilum is associated with a histone-like protein that has the following properties: it has a high content (23%) of basic amino acids, is positively charged at neutral ph, is soluble in acid, and can stabilize dna against thermal denaturation. in polyacrylamide gel electrophoresis, in the presence of either sodium dodecylsulfate or urea, it migrates at the same rate as histone iv (f2a1) of calf thymus. the amino acid composition, however, it unusually r ...	1975	238622
ultrastructure of lipopolysaccharide isolated from thermoplasma acidophilum.	the fine structure of lipopolysaccharide isolated from thermoplasma acidophilum was examined by electron microscopy. negative staining of the lipopolysaccharide revealed long, ribbon-like structures with some branching. the average width of the lipopolysaccharide ribbons was 5 nm. treatment of the lipopolysaccharide with 0.5% sodium dodecyl sulfate resulted in the dissociation of the ribbon-like structures to spherical- and vesicular-shaped particles and some short, rodlike structures. results s ...	1975	46226
polypeptide nature of growth requirement in yeast extract for thermoplasma acidophilum.	the active component(s) in yeast extract required by thermoplasma acidophilum for growth is polypeptide in nature. a fraction from yeast extract was isolated and partially characterized as one or more peptides of molecular weight about 1,000 containing 8 to 10 amino acids. although it was composed largely of basic and dicarboxylic amino acids, only one amino group per molecule was free. the polypeptide(s) appeared to bind avidly to cations. no other organic compounds except glucose were needed b ...	1975	1102535
intracellular ph of thermoplasma acidophila.	thermoplasma acidophila, a mycoplasma-like organism, was grown at 56 degrees c and ph 2. the intracellular ph of this organism is close to neutral as measured by the distribution of a radioactive weak organic acid, 5,5-dimethyl-2,4-oxazolidinedione, across the plasma membrane. the cell can maintain the ph gradient when subjected to heat or to metabolic inhibitors. our experiments seem to indicate that a major portion of the ph gradient is not maintained by active processes, but rather by a donna ...	1975	236035
membrane properties of thermoplasma acidophila.	plasma membranes were isolated from thermoplasma acidophila, a mycoplasma-like organism which grows optimally at ph 2 and 59 degrees. cells in concentrated suspensions were lysed by titrating to ph 9.3. the membranes were purified by washing at ph 10 and centrifuging in a discontinuous sucrose gradient. membrane purity was assessed by electron microscopy, determination of deoxyribonucleic acid content, polyacrylamide gel electrophoretic behavior. gel patterns and amino acid composition of cells ...	1975	234745
lipid phase transitions in membrane vesicles from thermoplasma acidophila.		1974	4370165
a new class of lipopolysaccharide from thermoplasma acidophilum.		1974	4371772
immunofluorescence approach to the study of the ecology of thermoplasma acidophilum in coal refuse material.	specific immunofluorescence staining was applied to the study of the localization, distribution, and growth of thermoplasma acidophilum in its natural habitat, the coal refuse pile. different antigenic groups of t. acidophilum could be isolated from the same refuse pile, and the same antigenic groups were isolated from piles from different geographical areas. no correlation could be established between the antigenic groups and the ph or temperature of the habitats. brightly fluorescing cells of ...	1974	4602306
immunodiffusion analysis of membranes of thermoplasma acidophilum.	isolates of thermoplasma acidophilum were divided into serological groups based on immunodiffusion studies of solubilized-membrane preparations.	1974	4210340
scanning electron microscopy of thermoplasma acidophilum.	the scanning electron microscope was utilized to observe the morphology of the thermophilic, acidophilic mycoplasma, thermoplasma acidophilum. upon examination of the surface morphology, the size and shape of this unusual mycoplasma revealed its similarity to the other mycoplasmas that have been investigated.	1974	4436262
immunological analysis of glycolipids and lipopolysaccharides derived from various mycoplasmas.	the lipids and lipopolysaccharides of five mycoplasmas were examined for complement-fixing activity to antimembrane rabbit sera. total glycolipid fractions and the aqueous phenol fractions (lipopolysaccharides) from the membranes of acholeplasma laidlawii, a. modicum, a. axanthum, and mycoplasma neurolyticum exhibited significant antigenic activity. the glycolipids and phosphoglycolipids from thermoplasma acidophilum were either anticomplementary or did not react due to their extreme hydrophobic ...	1974	4215761
characterization of the membranes of thermoplasma acidophilum.	thermoplasma acidophilum grows optimally under aeration at 59 c and ph 2. both intact cells and membranes disaggregate below ph 1 and above ph 5, producing no sedimentable particles. increase in ionic strength at ph 5 or below results in cellular lysis and membrane disaggregation. membranous components produced by lysis at alkaline ph reaggregate upon reduction of both ph and ionic strength. osmotic environment plays little role in cellular stability. membranes prepared by sonic lysis at ph 5 ex ...	1973	4583228
lipids of thermoplasma acidophilum.	cells of thermoplasma acidophilum contain about 3% total lipid on a dry weight basis. total lipid was found to contain 17.5% neutral lipid, 25.1% glycolipid, and 56.6% phospholipid by chromatography on silicic acid. the lipids contain almost no fatty acid ester groups but appear to have long-chain alkyl groups in ether linkages to glycerol. the phospholipid fraction includes a major component which represents about 80% of the lipid phosphorus and 46% of the total lipids. we believe this componen ...	1972	4344918
a thermophilic, acidophilic mycoplasma isolated from a coal refuse pile.	a thermophilic, acidophilic procaryote lacking a cell wall has been isolated from a coal refuse pile which had undergone self-heating. electron micrographs, chemical assays for hexosamine, and the inability of vancomycin to inhibit growth confirm the lack of a cell wall. the apparent ability of the organism to reproduce by budding and the low guanine plus cytosine content of its dna indicate a relation to the mycoplasmas. the temperature optimum of the organism is 59 degrees c, and growth occurs ...	1970	5481857