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C Endresen

Publications and source records attributed to C Endresen.

At least 37 records · Page 2Linked to original sources
PubMed1990

Stability of the nucleotide sequence of the phosphoprotein gene of measles virus during lytic infections.

Three clones with cDNA inserts encoding large portions of the measles virus phosphoprotein mRNA were characterized and compared with a previously published sequence of the Edmonston strain of measles virus. The two cloned viruses were separated by more than 100 passages. Only one out of 1477 nucleotides differed in the two sequences reflecting a very low mutation rate of the phosphoprotein gene during dilute lytic passages. The discovery that a third reading frame in the phosphoprotein gene may code for a novel peptide chain in addition to the P and C peptides may explain some of the high stability of the gene. The new reading frame was accessed by a translational shift caused by insertion of one extra G at a particular site in one of three otherwise identical cDNA sequences. A discrepancy was also found between the presumably high error rate of viral RNA polymerases and the stability of nucleotides in which mutations would not lead to amino acid substitutions. A few errors in the previously published sequence were discovered and the corrections are presented.

Base Sequence↗
PubMed1989

Two species of the phosphoprotein mRNA with differently edited reading frames discovered in measles virus infected Vero cells. Brief report.

One cDNA clone representing the phosphoprotein mRNA sequence of the Edmonston strain of measles virus contained 4 G nucleotides at a particular position. Two other clones contained 3 G nucleotides at the same position. Otherwise the nucleotide sequence were identical. The mRNA with 3 G nucleotides codes for the 70 kD phosphoprotein. The mRNA with 4 G nucleotides may code for a putative new peptide with 231 aminoterminal amino acids in common with the P protein whereas the 68 carboxyterminal amino acids are different from any amino acid sequence of the phosphoprotein. Thus the consequence of the insertion of one additional G is a translational shift to a shorter open reading frame. There are several indications that the observation is of biological significance.

Animals↗
PubMed1988

Characterization of a new serotype of infectious pancreatic necrosis virus isolated from Atlantic salmon.

Virus particles isolated from hatchery reared fish with infectious pancreatic necrosis (IPN) were neutralized by homologous immune sera but not by immune sera raised against IPN virus serotype 1, 2, and 3. This virus isolate, called the N1 strain, was detected in one year old Atlantic salmon (Salmo salar) during an outbreak with histopathological lesions of IPN and slightly increased mortality. The polypeptide pattern of N1 virus differed markedly from that of the three classical IPN virus serotypes. Double stranded RNA isolated from the N1 virus particles, co-migrated during agarose gel electrophoresis with nucleic acid isolated from the IPN virus Jasper and Ab strains. Nucleic acid hybridizations using low stringency washing conditions and a synthetic DNA oligonucleotide probe (representing the 3' end of the A segment of the Jasper strain) gave positive results with the IPN virus Jasper, Ab, Sp, and N1 strains. The results presented in this paper show that the N1 isolate differs immunologically and biochemically from the IPN virus serotypes 1, 2, and 3 and may represent a new serotype of IPNV.

Animals↗
PubMed1988

Purification and partial characterization of an IgM-like serum immunoglobulin from Atlantic salmon (Salmo salar).

An IgM-like immunoglobulin was isolated from pooled sera collected from healthy Atlantic salmon. The immunoglobulin was purified by means of gel filtration followed by ion-exchange chromatography. It eluted from the ion-exchange column as two distinct peaks, but the two IgMs seems to be identical in their molecular natures except for net charge. The molecular weight of the unreduced (native) IgM was determined to be approximately 800 kilo Daltons (kD) when estimated by dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). However, when the molecular weight of the native IgM was estimated by gel filtration, a molecular weight of 1000 kD was obtained. Furthermore, the molecular weights of the heavy and the light chains were estimated by SDS-PAGE analysis to be about 72 and 27 kD respectively. The amount of IgM was found to range from 80 to 130 mg/100 ml serum. Isoelectric focusing demonstrated that the major part of the IgM molecules focused between pH 5 and pH 6.

Animals↗
PubMed1988

Properties of a protein from Staphylococcus capitis that binds human serum high density lipoprotein.

A high density lipoprotein (HDL) binding component from the cell wall of Staphylococcus capitis, possessing both HDL binding and HDL precipitating activity, has been partially characterised. Growth of the bacteria on medium containing cysteine or in presence of CO2, was found to induce the synthesis of this factor. Analysis show an incorporation of radioactive amino acids into the factor, and also its sensitivity to trypsin, indicating strongly that the HDL binding factor is of protein nature. Gel-filtration experiments showed that the HDL binding protein had an elution volume corresponding to a molecular weight of about 150K. However, SDS-PAGE analysis of HDL binding protein, purified by affinity chromatography, showed that the 150K component was composed of subunits of a low molecular weight protein (7K). As judged by the incorporation of radiolabelled amino acids, the HDL binding protein may, under certain growth conditions, constitute as much as 15% of the total protein in the autolytic extract from the bacteria.

Bacterial Proteins↗
PubMed1988

Construction and characterization of complementary DNA libraries from Vero cells infected with measles virus.

Several cDNA libraries have been generated from poly(A)RNA from Vero cells infected for 24 hours with measles virus. Different protocols for cDNA library construction were compared and some critical steps were evaluated. From these libraries, a measles virus specific sequence corresponding to 885 of 1600 nucleotides of the measles virus phosphoprotein gene has been cloned. The phosphoprotein gene accounts for 1% of the total cDNA library after 24 hours of infection at 37 degrees C. The technique of differential colony hybridization was used to analyze the distribution and change of the poly(A)-RNA expression in uninfected Vero cells and in cells infected with measles virus for 24 hours.

Animals↗
PubMed1987

Antibodies to various bacterial cell wall peptidoglycans in human and rabbit sera.

Sera from patients with verified systemic staphylococcal infection contained antibodies reactive with peptidoglycan (PG) from Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Micrococcus lysodeikticus, Bacillus subtilis, and Escherichia coli. The presence of anti-PG cross-reactive antibodies was verified in patient sera by inhibition studies with the various bacterial PGs. Antibodies to nonstaphylococcal PGs were also elevated in sera from rabbits immunized with S. aureus PG. Antibodies to S. aureus PG were removed with the synthetic peptide analogs of S. aureus PG, the L-Lys-D-Ala-D-Ala, L-Lys-D-Ala, and (Gly)5 determinants, as well as with an S. aureus PG peptide fragment containing the determinants D-Ala-D-Ala and L-Lys-D-Ala. Isolated antibodies to the PG peptides, both synthetic and native, were reactive with S. aureus and S. epidermidis PGs. The antibodies to the D-Ala-D-Ala and the L-Lys-D-Ala determinants were also reactive with S. pyogenes PG, but not with PGs from M. lysodeikticus, B. subtilis, and E. coli.

Animals↗
PubMed1984

IgM antibodies in sera from patients with chronic active hepatitis reacting with the measles virus matrix protein and nucleoprotein.

The antigenic specificity of measles virus IgM antibodies in sera from patients with chronic active hepatitis not caused by hepatitis B virus has been examined. An immunosorbent column containing antihuman IgM covalently bound to Sepharose was used to pick up IgM from the sera. Radiolabelled measles virus antigens were then allowed to react with the IgM antibodies. The immune complexes were eluted and analysed by sodium dodecyl sulfate [SDS]-polyacrylamide gel electrophoresis. Four sera from patients with hepatitis B surface antigen [HBsAg]-negative chronic active hepatitis with high measles virus haemagglutination inhibition [HI] and complement fixation [CF] antibody titres and positive enzyme-linked immunosorbent assay [ELISA] for measles-virus-specific IgM were examined. The results were compared with those obtained using sera from patients with an acute measles virus infection and from healthy controls. In both patient groups, IgM antibodies with specificity against the matrix protein represented the major portion of the measles virus IgM. IgM antibodies against the measles virus nucleoprotein and probably against host-cell-derived actin were also present. The patient sera contained only traces of IgM antibodies with specificity against the measles virus haemagglutinin or fusion protein. No specific IgM antibodies were found in sera from healthy controls.

Actins↗
PubMed1984

Staphylococcus aureus peptidoglycan studied by electron microscopy of immunoperoxidase-treated sections of cell walls.

The immunoperoxidase technique in combination with electron microscopy was used for demonstration of antigenic determinants of Staphylococcus aureus peptidoglycan. Isolated antibodies against four synthetic peptides with amino-acid sequences similar to those found in native staphylococcal peptidoglycans were used. A homogeneous staining of the cell wall from the outer surface to the cell membrane was demonstrated.

Cell Wall↗
PubMed1984

Antibodies to Staphylococcus aureus peptidoglycan and lipoteichoic acid in sera from blood donors and patients with staphylococcal infections.

An enzyme-linked immunoassay (ELISA) was used to detect antibodies in human sera to Staphylococcus aureus peptidoglycan (PG) and lipoteichoic acid (LTA). All the sera from the blood donors contained IgG antibodies to both substances. Among the sera from 34 patients with bacteriologically verified, serious S. aureus infections, 71 per cent contained significantly elevated levels of anti-PG antibodies and 76 per cent of anti-LTA antibodies. Among the sera from 38 patients with suspected but not bacteriologically verified staphylococcal infections, 58 per cent contained significantly elevated levels of anti-PG antibodies and 74 per cent of anti-LTA antibodies. The levels of antibodies to PG correlated well with the levels of antibodies to LTA, but the latter occurred over a broader range in the patient sera. Elevated antibody values were, however, also found in some patients with serious, non-staphylococcal infections. The diagnostic value of PG and LTA antibodies has to be further investigated.

Antibodies, Bacterial↗
PubMed1982

Characterization of measles virus-specific antibodies in sera from patients with chronic active hepatitis.

Measles virus-specific antibodies in sera from patients with HBsAg-negative chronic active hepatitis and raised antibody titres against measles virus, have been examined by crossed immunoelectrophoresis. The immunoprecipitates were further analysed by SDS-polyacrylamide gel electrophoresis. Five measles virus-specific precipitation lines were demonstrated using measles virus-infected cells solubilized with Triton X-100. The three major precipitation lines were analysed by SDS-PAGE and contained the virus polypeptides: nucleoprotein, NP (MW approximately 60 000); haemoagglutinin, H (MW approximately 80 000) and fusion protein F1 (MW approximately 40 000). Considerably higher amounts of antibodies against these three virus polypeptides were demonstrated in the patient sera than in sera from healthy controls. By SDS-PAGE analysis of radiolabelled immune complexes adsorbed to Sepharose-protein A, antibodies against five measles virus polypeptides: NP, H, F1, P protein (MW approximately 70 000) and matrix protein, M (MW approximately 37 000) were demonstrated in the patient sera.

Antibodies, Viral↗
PubMed1981

Purification of measles virus H polypeptide and of F polypeptide.

Measles virus was disrupted by Tween 80 and ether and subjected to isoelectric focusing in granular gel. The two surface envelope polypeptides, the one showing haemagglutinating activity (H) and the one making up the structural basis of the haemolytic and fusion activity (F) banded together at pH 5.2. The two envelope polypeptides were also isolated together after adsorption to a Lentil-lectin column. Separation of the two polypeptides was performed by gel filtration on Sephadex G-150 in the presence of 8 M urea. After separation both the H and F polypeptides fixed to the lectin column. It was demonstrated that the column, after having fixed the two polypeptides, absorbed anti-H and anti-F antibodies from a rabbit anti-measles virus immune serum. Thus the antigenic reactivity of the isolated surface polypeptides remained intact.

Chromatography, Affinity↗
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↗
PubMed1979

Isolation of enzymatically derived fragments of porcine IgG and an examination of their reactivity against staphylococcal protein A.

Papain digestion of porcine IgG in the absence of cysteine resulted in a rather poor yield of fragments (less than 5 per cent). In the presence of cysteine, 70 to 80 per cent of the IgG was degradated in 4 h. Fragments with molecular weight of about 100,000 and 50,000 were separated by gel filtration. The minor fraction (mol. wt. 100,000) most probably consisted of F(c)2 fragments. Fab/c fragments with both Fc and Fab determinants, and also probably some F(ab)2-like fragments. The F(c)2 fragments appeared to be a dimer of Fc stabilized by disulphide bonds. The second main fraction (mol. wt. 50,000) contained Fc and Fab fragments. Mild reduction of the Fc fragments resulted in Fc subfragments of different sizes, thus indicating that papain cleavages had occurred on different spots in the Fc chain. Non-reduced Fc fragments therefore seem to consist of several Fc subfragments stabilized by disulphide bonds. The protein A reactivity of the isolated Fc fragments were rather low compared to the reactivity of intact IgG, respectively 5--15 and 90 per cent. In addition, protein A reactive Fab fragments were isolated from normal porcine IgG.

Animals↗
PubMed1979

The binding of protein A of immunoglobulin G and of Fab and Fc fragments.

Results are presented to show that protein A (pA) may fix to the Fab region of IgG outside the antigen binding site. Thus, pA-reactive Fab fragments were isolated both from specific anti-egg albumin and specific anti-measles virus antibodies. A probable significance of this Fab reactivity in the precipitation reaction between IgG and pA is discussed. Reactive IgG from human, guinea pig, rabbit, and porcine normal sera all showed similar avidity towards pA. Slight differences between IgG subclasses were, however, observed. The avidity of pA-reactive Fab and Fc fragments, isolated from normal porcine IgG, was highest in the latter.

Albumins↗
PubMed1978

Isolation of enzymatically derived fragments of guinea pig IgG and an examination of their reactivity against Staphylococcal protein A.

Papain digest of guinea pig IgG2 was separated by ion-exchange chromatography into five fractions, one containing mainly Fab and four Fc fractions. Covalently linked Fc (cFc) and non-covalently linked Fc fragments (nFc) were present, both with a molecular weight (Mw) of about 56,000. nFc was split into half fragments by gel filtration under dissociating condition (Mw 25,000 to 27,000). An incomplete Fc fragment (iFc) was also isolated (Mw 36,000), which consisted of a Fc chain (Mw 26,000) non-covalently linked to a piece of another chain. These preparations all reacted with protein A. In addition, the Fc' fragment (Mw 22,000), which is the C-terminus of the Fc fragment, was isolated. This fragment did not react with protein A. The cFc was treated with acid and then digested with trypsin at pH 7.8 for 45 s. The digest were separated into four fractions (I-IV) by gel filtration on Sephadex G-100. Fraction I was indistinguishable from intact Fc, fraction II contained an incomplete covalent Fc fragment (Mw 34,000 to 38,000). Both these fragments reacted with protein A. Fraction IV consisted of fragments belonging to the C-terminus, and was protein A non-reactive. Fraction III was shown to contain a mixture of fragments belonging to fractions II and IV.

Animals↗