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Biomedical subjects

F Brown

Publications and source records attributed to F Brown.

At least 217 records · Page 12Linked to original sources
PubMed1979

Purification of poliovirus by affinity chromatography.

Poliovirus type 1 (Mahoney strain) has been purified by retention on a Sepharose 4B-antibody column and elution with 3M K thiocyanate. The virus was recovered in excellent yield and its purity was as high as that achieved by detergent treatment followed by sucrose gradient centrifugation. The column could be re-used and its capacity was sufficiently high to make it a useful method for the purification of milligram quantities of the virus.

Chromatography, Affinity↗
PubMed1979

The physico-chemical characterization of bovine ephemeral fever virus as a member of the family Rhabdoviridae.

This study of the physico-chemical properties of bovine ephemeral fever virus was initiated to establish whether or not it should be classified as a rhabdovirus. In contrast to the regular bullet-shaped morphology of some rhabdoviruses the virus particles are often cone-shaped or slight variants from bullet-shaped. The virion contains single-stranded RNA sedimenting at 42S and six proteins with mol. wt. of 164, 101, 64, 53, 43 and 29 x 10(3). The protein P101 is located on the surface of the virus and is glycosylated. It is removed by treatment of the virus particles with trypsin. Protein P64, the nucleoprotein, was found to be a phosphoprotein, like the N protein of rabies virus, whereas in vesicular stomatitis virus NS is the phosphorylated protein. Virus harvests contain defective-interfering particles. The particles are short cone-shaped forms about one-third the length of the infectious virion and similar in morphology to defective-interfering particles of vesicular stomatitis virus. These particles interfere with the replication of bovine ephemeral fever virus but not with the Indiana serotype of vesicular stomatitis virus. They contain single-stranded RNA sedimenting at 18 to 20S. The particles appear to have a protein composition identical to that found in the virus particle. The physico-chemical properties of bovine ephemeral fever virus justify its inclusion in the family Rhabdoviridae. The protein composition differs in detail from that found for vesicular stomatitis and rabies viruses, but is similar to that found for Obodhiang and kotonkan, two rabies serogroup viruses isolated from insects in Africa.

Animals↗
PubMed1979

Purification and identification of the RNA-dependent RNA polymerase of foot-and-mouth disease virus.

The RNA-dependent RNA polymerase induced in BHK 21 cells by infection with foot-and-mouth disease virus has been isolated from the replication complex. It contains a major, virus-coded protein with mol. wt. 56 000 which appears from serological studies and tryptic peptide mapping to be the same as the virus infection associated (VIA) antigen and the protein P56 found in cells infected with the virus. Other virus coded proteins and a host cell protein were present in the partially purified replication complex but were removed by digestion with ribonuclease T1, leaving only the major virus coded protein. The tryptic peptide maps of the VIA antigen of the seven serotypes of the virus were similar, suggesting a high level of conservation in that region of the genome coding for the RNA polymerase of each type.

Animals↗
PubMed1979

Comparative biochemical and serological analysis of five isolates of a single serotype of foot-and-mouth disease virus.

A comparison has been made of some of the biochemical and serological characteristics of five isolates of foot-and-mouth disease virus (FMDV), serotype A. Three of the viruses have been assigned to the same subtype, A22; the other two belong to different subtypes, A5 and A24. RNA competition hybridization and two-dimensional electrophoresis of the oligonucleotides produced by ribonuclease T1 showed that the three A22 viruses formed a group which could be distinguished from the A5 and A24 viruses. However, the three A22 viruses showed some differences by both tests. Analysis of the virus polypeptides by polyacrylamide gel electrophoresis methods also distinguished the A22 viruses as a group distinct from the A5 and A24 viruses, but small differences within the A22 group were observed using electrofocusing techniques. Serological differences were observed between the viruses using complement fixation tests and by competition radioimmunoassay with antisera obtained from guinea pigs infected with these viruses. The greatest similarity occurred between the viruses previously subtyped as A22, with A5 and A24 being distinct from the A22 group and from each other. The relationship of the biochemical and serological data is discussed.

Animals↗
PubMed1979

Comparison of the antibodies elicited by the individual structural polypeptides of foot-and mouth disease and polio viruses.

Antibody produced against preparations of VP1, one of the four structural polypeptides of foot-and-mouth disease virus, neutralized the virus and reacted with both full and empty particles in radioimmunoassays (RIA). Antiserum against VP2 reacted with artificial empty particles of the virus but not with full particles. In contrast, none of the individual polypeptides of poliovirus produced antisera which neutralized the virus nor reacted with it in RIA. However, antisera produced with VP1 and VP2 reacted with artificial empty particles in RIA.

Animals↗
PubMed1979

Molecular approach to the epidemiology of swine vesicular disease: correlation of variation in the virus structural polypeptides with serological properties.

Variation has been observed in the structural polypeptides of swine vesicular disease viruses isolated from the United Kingdom and Hong Kong. Despite the limited number of isolates examined, several distinct polypeptide patterns were obtained when the virus structural proteins were examined by polyacrylamide gel electrophoresis. Isolates from outbreaks in the United Kingdom which were known to be connected gave the same polypeptide pattern, whereas viruses with different polypeptide patterns could not be traced to a common source. The different polypeptide patterns were obtained consistently and were not altered by passage of the virus in tissue culture. In general, isolates with identical polypeptide patterns could not be distinguished by neutralization or antibody blocking tests or by competition radioimmunoassays. However, isolates with different polypeptide patterns could be differentiated by antibody blocking tests or radioimmunoassay. The correlation between the serological tests and the polyacrylamide gel electrophoresis analyses illustrates the value of analyzing structural polypeptides in the epidemiological study of swine vesicular disease.

Animals↗
PubMed1979

Rhabdoviridae. Report of the Rhabdovirus Study Group, International Committee on Taxonomy of Viruses.

The family Rhabdoviridae comprises approximately 75 viruses infecting vertebrates, invertebrates and plants. The main characteristics of the member viruses are: (i) the viruses infecting vertebrates and invertebrates are bullet-shaped and the viruses infecting plants are usually bacilliform; (ii) the viruses have particle lengths varying from 130 to 380 nm and widths varying from 60 to 95 nm; (iii) the viruses possess unit-membrane envelopes from which protrude spikes 5 to 10 nm long; (iv) the viruses have precisely coiled helical nuecleocapsids with a diameter of approx. 50 nm; (v) most of the viruses which have been studied contain 5 proteins; the prototype, vesicular stomatitis virus, contains proteins designated L (large), G (glycoprotein), N (nucleoprotein), NS (nonstructural) and M (matrix); N or NS is phosphorylated in most members which have been studied; (vi) the viruses contain single-stranded RNA which is transcribed into several messenger RNA species with sizes corresponding to the structural proteins; (vii) the nucleocapsid contains the RNA-dependent RNA polymerase and is infectious; and (viii) many of the viruses produce morphologically distinct defective-interfering (T) particles.

RNA, Viral↗
PubMed1978

Treatment of elevated intracranial pressure in Reye syndrome.

Continuous intraventricular monitoring of intracranial pressure appears to be a useful aid in the management of patients with Reye syndrome, especially those in stage 3 or 4 coma, in which the mortality rate remains high. Elevations in intracranial pressure can be treated promptly and before the patient shows clinical signs of deterioration. Careful attention to adequate airway care is essential. The use of paralytic agents to reduce pressure secondary to muscle movement is useful. The minimum dose of mannitol required can be carefully titrated, and sudden pressure changes can be combated by release of small amounts of cerebrospinal fluid.

Adolescent↗
PubMed1978

Proteins induced by infection with caliciviruses.

Three polypeptides with mol. wt. 100 (P100), 80 (P80) and 65 (P65) X 10(3) were found in calicivirus infected cells. P100 and P80 were present in sub-molar amounts compared with P65 and no precursor product relationship between the three polypeptides could be demonstrated using pulse-chase experiments or selective inhibitors of protein synthesis and of proteases. In the presence of protease inhibitors a polypeptide with mol. wt. 120 X 10(3) (P120) was demonstrated which appeared to be the precursor of P100. Possible mechanisms of translation in the caliciviruses are discussed.

Animals↗
PubMed1978

Further physicochemical characterization of Nodamura virus. Evidence that the divided genome occurs in a single component.

Nodamura virus, a small non-enveloped RNA virus, contains two species of RNA sedimenting at 22S (RNA-1) and 15S (RNA-2), a single major polypeptide of mol. wt. 40 X 10(3) and two minor polypeptides, of mol. wt. 38 and 43 X 10(3). Evidence is presented that the two RNA species are in the same particle. Although extraction of the virus with SDS-phenol yields the two species of RNA as separate entities, gentle treatment of the virus with guanidine and low concentrations of SDS releases the RNA as a 27S component which contains both RNA-1 and RNA-2 together with a trace of protein. It seems likely that the two RNA species replicate separately because double stranded molecules corresponding to the single stranded RNA-1 and RNA-2 molecules were present in BHK cells infected with the virus.

Chlorides↗
PubMed1978

Tryptic peptide analysis of the structural proteins of vesicular stomatitis virus.

The individual structural polypeptides of vesicular stomatitis virus have been examined by tryptic peptide analysis of 35S-methionine preparations labelled in vivo and 125I-preparations labelled in vitro. Isolates of the two classical serotypes of the virus (Indiana and New Jersey) and of a sub-type of the Indiana serotype, Brazil virus, were compared. The study showed that the major internal proteins of all three viruses gave similar maps, whereas the surface glycoproteins gave distinct maps that had very few spots in common. The map of the glycoprotein of Brazil virus, which has been shown previously to be more closely related serologically to Indiana virus than to New Jersey virus, did not show any greater similarity to the Indiana virus than to the New Jersey virus glycoprotein. On the other hand, peptide maps of the nucleoprotein and matrix protein showed Indiana and Brazil viruses to be more closely related to each other than to New Jersey virus.

Amino Acids↗
PubMed1978

A model for vesicular exanthema virus, the prototype of the calicivirus group.

The structure of vesicular exanthema virus, the prototype member of the calicivirus group, has been studied in more detail. The RNA comprises 18% of mol. wt. of about 2.8 x 10(6), based on polyacrylamide gel electrophoresis experiments in the presence of formaldehyde. The virus contains one major polypeptide, mol. wt. 70 x 10(3) as determined by polyacrylamide gel electrophoresis and by chromatography on Sepharose 6B in the presence of 6 M-guanidine. Further evidence for the presence of a single major polypeptide was obtained by tryptic peptide analysis of 35S-methionine labelled virus. The mol. wt. of a protein oligomer produced by adjusting the pH of virus suspensions to 3.5 was c. 200 x 10(3). On the basis of these data we propose a T = 3 model for the virus capsid incorporating 180 copies of the virus protein.

Animals↗
PubMed1978

Early events in the interaction between foot-and mouth disease virus and primary pig kidney cells.

Foot-and-mouth disease virus (FMDV) attached to pig kidney cells at 0 degrees C and could only be recovered in a form with a sedimentation coefficient and buoyant density lower than that of the native virus. Incubation of the virus-cell complex at 37 degrees C caused disruption of about 80% of the particles into a 12S protein sub-unit that had the same polypeptide composition as that produced by reducing the pH of the virus below pH7. The remaining 20% had the same polypeptide and RNA composition as the native virus but it had a lower sedimentation coefficient, buoyant density and specific infectivity. These lower values are probably due to the association of the virus with cell membrane components. The 12S subunits were shown to be located inside the cell, indicating that disruption of the virus had occurred within the cell. The results are discussed in relation to the different cell mediated alteration of other picornaviruses.

Adsorption↗
PubMed1978

A re-appraisal of the biochemical map of foot-and-mouth disease virus RNA.

The proteins induced by infection of BHK 21 cells with foot-and-mouth disease virus have been compared by tryptic peptide analysis. The results indicate that there are three primary products 5'--P88, P52, P100--3'. The polypeptide P56, which we considered previously to be a primary product, is derived from the region of the genome that codes for P100. The results indicate that there are alternative cleavage pathways of P100, the polypeptide coded for by the 3' end of the genome.

Aphthovirus↗