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H B Jensen

Publications and source records attributed to H B Jensen.

At least 37 records · Page 2Linked to original sources
PubMed1989

Purification and partial characterization of a major outer-membrane protein of Fusobacterium nucleatum.

The major outer-membrane proteins of 40-41 kDa were identified by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) in Fusobacterium nucleatum strains ATCC 10953, ATCC 25586, F3, F6 and Fev1. The proteins were purified by preparative gel electrophoresis. Their behaviour in gel filtration and gel electrophoresis, their sensitivity to proteolytic enzymes, and their amino acid composition were investigated. The purified proteins were partly sequenced from the N-terminal end. A 36.5 kDa portion was protected against extrinsic proteolytic (trypsin, chymotrypsin or pronase) digestion of whole cells. This polypeptide was isolated and partially sequenced from the N-terminal end. From these data and data from extrinsic iodination it was concluded that the N-terminal end of the protein is probably exposed on the surface of the cell. A database search revealed amino acid sequence similarity in an Ala-Pro-rich region of outer-membrane protein A (OmpA) in other Gram-negative bacteria.

Amino Acid Sequence↗
PubMed1989

Utilization of amino acids and peptides by Fusobacterium nucleatum.

Fusobacterium nucleatum strains ATCC 10953, Fevl, F1, F3, and F6 utilized amino acids, in particular glutamate, histidine, and aspartate were common to all strains. Strain differences were observed in the utilization of threonine, serine, lysine, tyrosine, and methionine, and only strain ATCC 10953 utilized all these amino acids. The glutamate and histidine pools were in all cases fully depleted before the other amino acids were attacked and at the same time all strains except 10953 started to utilize peptides at a noticeable rate. For strain Fevl, glutamyl- and aspartyl-containing peptides seemed to be of considerable nutritional importance, and this strain did not grow on a medium based on amino acids alone. On the other hand, strain 10953 did not utilize any peptides to a noticeable extent, and it could grow on an amino acid based medium.

Amino Acids↗
PubMed1988

Outer membrane protein pattern of Eubacterium plautii.

The outer membrane SDS-PAGE pattern of Eubacterium plautii was characterized by a large number of surface exposed low- and high-molecular-mass proteins. Silver stainable carbohydrate was not present. The pattern was clearly distinct from those of outer membrane preparations of Eubacterium saburreum and Fusobacterium nucleatum. The results are compatible with a Gram-positive cell wall structure in E. plautii.

Bacterial Outer Membrane Proteins↗
PubMed1987

Partial characterization of a peptidoglycan-protein complex from Fusobacterium nucleatum Fev1.

A protein in the cell wall of Fusobacterium nucleatum Fev1 remained associated with the peptidoglycan during extraction with various detergents and organic solvents. On digestion of this peptidoglycan-protein complex (PPC) with murein hydrolases, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed polypeptide bands with apparent molecular weights (MWs) in the range of 3000 to 40,000. After reaction with maleic anhydride the electrophoretic mobilities of these polypeptide bands increased to those of MWs 3000 to 12,000. The PPC protein showed a limited susceptibility toward trypsin, giving polypeptides that migrated in SDS-PAGE as a diffuse band with MW in the range of 3000 to 6000. The amino acid composition of all polypeptide bands eluted from SDS-PAGE was very similar, whichever enzyme was used for the solubilization of the PPC, and was nearly identical to that found for the protein moiety of the PPC. On the basis of a MW of 3000 for a protein unit, about one molecule of protein was found per five peptidoglycan subunits. Lanthionine was not found associated with released polypeptide, and muramic acid and glucosamine were either absent or present in amounts less than one molecule per protein unit. The PPC was immunogenic in rabbits, and purified anti-PPC IgG reacted with murein hydrolase-released protein separated on SDS-PAGE but preferentially with bands of MWs greater than 18,000.

Bacterial Proteins↗
PubMed1986

Outer membrane proteins of Fusobacterium nucleatum Fev1.

Outer membrane enriched material from six strains of Fusobacterium nucleatum was analysed by SDS-PAGE. The protein profiles of all the strains were dominated by proteins with molecular masses of about 40 kDa, and a very high degree of homology in relation to apparent molecular masses was observed. In all strains except Fev1, one of the most dominant proteins exhibited heat modifiable properties, having an apparent molecular mass of about 38 kDa and 42 kDa when heated in SDS at 50 and 100 degrees C, respectively. None of the proteins of the outer membrane of F. nucleatum Fev1 demonstrated such heat modifiable properties. The 40 kDa protein, and several other proteins, appear to be both exposed on the cell surface and peptidoglycan associated.

Autoradiography↗
PubMed1984

Antibacterial properties of human lysozyme toward Fusobacterium nucleatum Fev1.

Human lysozyme in physiologic concentrations (17-50 micrograms/ml) had apparently no effects on growth rate and viability of exponentially growing Fusobacterium nucleatum Fev1 cells, but cells in the stationary phase were affected. When grown in the presence of active lysozyme about 70% of the cells in late exponential phase (24-h culture) were able to form colonies, compared to about 100% in the control culture. About 24 h later the colony forming abilities were about 5% and 20%, respectively. Addition of lysozyme to suspensions of cells taken from any growth phase did not lead to any significant decrease in turbidity, that is, no more than 10% decrease at 650 nm. Control cells treated with acridine orange fluoresced with a uniform bright orange color, while the lysozyme treated stationary phase cells fluoresced more faintly. Intracellular granules were more preponderant in the latter cells. When incubated with the hydrophobic probe 8-anilinonaphthalene-1-sulfonic acid (ANS), lysozyme exposed cells gave approximately 20% higher fluorescence intensity than the control cells. Changes in the ultrastructure of the lysozyme treated cells were best studied in the transmission electron microscope using ultrathin sectioned preparations. The peptidoglycan layer became disorganized and apparently dissolved and the ordered structure of the cell wall had disappeared in zones. The cells, however, still retained their form, and only a few per cent had lost their cellular content. This explains why the turbidity of the solution did not change significantly.

Cell Wall↗
PubMed1982

Composition of peptidoglycans in Bacteroidaceae: determination and distribution of lanthionine.

Peptidoglycans of organisms belonging to the strictly anaerobic family Bacteroidaceae were investigated for the presence of lanthionine. Different procedures for the quantitation of lanthionine were compared. Performic acid and peroxide oxidation procedures on 35S-labeled peptidoglycan from Fusobacterium nucleatum Fev1 resulted in low yields of cysteic acid (42 and 60%, respectively) and many other additional unidentified oxidation products. Lanthionine was, however, recovered in high yield (89% or more) from acid hydrolysates of unoxidized peptidoglycans. Lanthionine was found exclusively in some species of Fusobacterium, in particular F. nucleatum, F. necrophorum, F. russi, and F. gonidiaformans, for which lanthionine may be ascribed a function as a taxonomic marker. Peptidoglycans of these bacteria are thus proposed to belong to a new chemotype, assigned A1 delta. One strain of Fusobacterium, F. mortiferum VPI 0473 contained both lanthionine and diaminopimelic acid in about equal proportions. Species of F.plauti had a composition atypic of gram-negative cells. Chemotypic differences were also indicated among the species of Bacteroides investigated. Thus, some species contained lysine and not diaminopimelic acid as the major dibasic amino acid (e.g., F. asaccharolyticus). It is concluded that peptidoglycans of gram-negative organisms constitute a somewhat more heterogeneous group than hitherto assumed.

Alanine↗
PubMed1981

Inhibition of T7 development at high concentrations of the phage.

Escherichia coli B exposed to high doses of bacteriophage T7 did not lyse. A similar effect was observed when the high dose was added within the first 7 min after primary infection. No viable phage was formed. DNA synthesis was inhibited rapidly and the nucleoid structure was absent. Protein synthesis was in general markedly reduced and so were the activities of the phage-specific enzymes endolysin and DNA polymerase. However, phage genes were transcribed both by the host RNA polymerase and by the phage-specific enzyme. We suggest that inhibition of phage development is due to structural alterations occurring in the cell wall/membrane such that replication is inhibited.

Bacteriolysis↗
PubMed1981

The specificity requirements of bacteriophage T4 lysozyme. Involvement of N-acetamido groups.

Bacillus cereus peptidoglycan with N-unsubstituted glucosamine residues was insensitive to treatment with bacteriophage T4 lysozyme. After N-acetylation with acetic anhydride, T4 lysozyme cleared solutions of the peptidoglycan and reducing sugars were liberated. The digestion products were mainly of high molecular weight, since the peptidoglycan is peptide cross-linked to a great extent. N-Propylation did not convert the partially N-unsubstituted peptidoglycan to a sensitive form. It is concluded that the acetamido groups are required for binding and/or catalysis by T4 lysozyme.

Acetamides↗
PubMed1980

Affinity chromatography of human saliva lysozyme and effect of pH and ionic strength on lytic activity.

Lysozyme from human saliva was purified in one step by affinity chromatography on chitin. The recovery, however, was always very low, typically 25-40%. When the cationic exchanger BioRex 70 was used, the enzyme was isolated from saliva with only minor loss of activity, and the product appeared to be 60-70% pure. This partially purified enzyme bound completely and reversibly to chitin and was thereby purified to homogeneity with little loss of activity (< 10%). Both saliva lysozyme and the chicken egg white lysozyme were found to exhibit their highest lytic activity at high pH/low ionic strength (pH 9.0, I = 0.03), and both enzymes required higher ionic strength) it was found, however, that the ratio of the specific activity of saliva lysozyme to that of chicken lysozyme varied considerably depending on the assay conditions used. We argue strongly, therefore, against the frequent use of chicken lysozyme as a standard of reference in work on human lysozyme.

Adsorption↗
PubMed1979

Demonstration of lanthionine as a natural constituent of the peptidoglycan of Fusobacterium nucleatum.

Peptidoglycan was purified from the oral bacterium Fusobacterium nucleatum strain Fev 1, using boiling sodium dodecyl sulfate and pronase. The composition of this peptidoglycan was found to be similar to that of other gram-negative bacteria, except that it lacked diaminopimelic acid. Lanthionine, the monosulfur analog of diaminopimelic acid, was identified as the diaminodicarboxylic acid of this peptidoglycan. It is assumed that lanthionine replaced diaminopimelic acid. Thus, the peptidoglycan of F. nucleatum Fev 1 is one of the few known sources of naturally occurring lanthionine.

Alanine↗
PubMed1976

The specificity requirements of bacteriophage T4 lysozyme.

A series of bacterial cell wall glycopeptides of low molecular weight and cell wall nucleotide precursors have been tested for their inhibitory action on the digestion by T4 lysozyme of a radioactively labeled linear uncrosslinked peptidoglycan. The disaccharide-peptides GlcNAc-MurNAc-l-Ala-D-Glu(A2pm) (C5) and GlcNAc-MurNAc-L-Ala-D-Glu(A2pm-D-Ala) (C6) as well as the monosaccharide-peptide MurNAc-L-Ala-D-Glu(A2pm) were found to be good competitive inhibitors (with similar Ki values) whereas the disaccharide-pentapeptide GlcNAcMurNAc-L-Ala-DGlu-Gly-L-Lys-D-Ala was a poor inhibitor. T4 lysozyme did not catalyse transglycosylation reactions from Escherichia coli B peptidoglycan to the disaccharide-peptide C6. No changes were seen in the circular dichroism spectra (200-250 nm) or fluorescence emmission spectra upon binding of the good inhibitors. The results obtained indicate that T4 lysozyme has a small active site capable of recognizing a unit consisting of MurNAc-L-Ala-D-Glu(A2pm).

Circular Dichroism↗
PubMed1975

Studies on the specificity of action of bacteriophage T4 lysozyme.

Lysozyme from bacteriophage T4 was found to digest a soluble, uncrosslinked peptidoglycan which is secreted by cells of Micrococcus luteus when incubated in the presence of penicillin G. Analysis of the enzymatic degradation products shows that T4 acts as an endo-acetylmuramidase capable of cleaving glycosidic bonds only at muramic acid residues that are substituted with peptide side-chains. The results indicate that the secreted peptidoglycan may consist of a mixture of chains, approximately half of which are substituted by peptide side chains on most of their muramic acid residues, while the other half is made up of chains in which the muramic acid moieties are unsubstituted.

Coliphages↗