Biomedical subjects

B K Rima

Publications and source records attributed to B K Rima.

At least 73 records · Page 4Linked to original sources

PubMed1990

Strain-variable editing during transcription of the P gene of mumps virus may lead to the generation of non-structural proteins NS1 (V) and NS2.

The sequence of the P (phosphoprotein) gene of mumps virus has been determined. It has two open reading frames, the first of which probably encodes the NS1 (or V) protein of mumps virus. Expression of the P protein requires the insertion of two non-templated residues to link the two ORFs in a process analogous to that observed in the P/V gene of simian virus type 5 to which mumps virus is closely related. Strain differences in the accuracy of insertion of non-templated G residues in the P/V gene transcripts have been described.

Amino Acid Sequence↗

PubMed1990

Humoral immune responses in seals infected by phocine distemper virus.

Recently the isolation and characterisation of a morbillivirus which caused high mortality in common seals (Phoca vitulina) in 1988 have been reported. Because of the clinical and pathological similarity of the disease in seals to that of distemper in dogs, the name phocine distemper virus (PDV) has been proposed. There are marked differences in the virus-induced proteins of PDV compared to other morbilliviruses and the humoral immune response of moribund and dead seals to PDV was restricted to some of the internal antigens of PDV, similar to the response described earlier for canine distemper virus infection in dogs.

Animals↗

PubMed1989

Inclusion body myositis: the mumps virus hypothesis.

The resemblance of the filamentous inclusions in inclusion body myositis (IBM) to mumps virus nucleoproteins and the report of immunoreactivity of the inclusions for mumps virus antigens have implicated the mumps virus in the etiology of IBM. We tested the mumps virus hypothesis by in-situ hybridization with a cDNA probe specific for the mumps virus nucleocapsid gene, and immunocytochemically with antibodies against "soluble" and "viral" mumps antigens. The tests were performed on muscle specimens (IBM, 20; acid maltase deficiency, 4; chloroquine myopathy, 2; nonweak control subjects, 5) and mumps virus-infected and uninfected HEp-2 cells. The in-situ hybridization study showed a strong specific signal in the infected HEp-2 cells but no specific signal in IBM, other myopathies, or nonweak control subjects. The immunocytochemical study showed specific binding of the antimumps antibodies to the infected HEp-2 cells but demonstrated only nonspecific binding of these antibodies around rimmed vacuoles in IBM, acid maltase deficiency, and chloroquine myopathy. These studies cast doubt on the mumps hypothesis of IBM.

Biopsy↗

PubMed1989

Long-term effect of elevated temperatures on SSPE virus expression in persistently infected rat glial cells.

Cultivation of measles virus (SSPE virus, Lec strain) persistently infected C6 rat glioma cells at 39 degrees C resulted in the loss of detectable expression of measles virus proteins. Temperature shift-back led to reactivation of measles virus even after maintenance of the cells at 39 degrees C for 15 days. In Northern blot analysis viral mRNA disappeared at 3 days after shift-up whereas 50 S viral genome-sized RNA was detectable until 6 days. The 50 S RNA decreased in quantity in rough correlation with dilution by cell passage at 39 degrees C. The 50 S viral RNA was found in the nucleocapsid fraction. On day 9 after shift-down of persistently infected cells, maintained at 39 degrees C for 15 days, 50 S viral RNA reappeared although mRNAs were not yet detected. Infectious center assays showed that the number of cells in the population at 39 degrees C, which contained an SSPE virus genome that could be reactivated, declined after temperature shift. Moreover, cell cloning experiments, in which single cells of cultures maintained for various lengths of time at 39 degrees C were incubated at 35 degrees C and examined by immunofluorescence, reconfirmed the above results. This indicates that the reactivation of SSPE virus described here was due to re-infection of virus-antigen negative cells with progeny virus produced by a few latently infected cells in the population. The biological significance of this phenomenon in the central nervous system virus infection is discussed.

Animals↗

PubMed1989

Mutated and hypermutated genes of persistent measles viruses which caused lethal human brain diseases.

Persistent measles viruses (MVs) causing lethal human brain diseases are defective, and the structure of several mutated matrix genes has been elucidated previously. The present study of four persistent MVs revealed a high number of differences from a consensus sequence also in other genes. Amino acid changes accumulated in the carboxyl terminus of the nucleocapsid protein and in the amino terminus of the phosphoprotein, but did not significantly alter these products, which are implicated in viral replication and transcription. The contrary is true for the envelope glycoproteins: In three of four cases, mutations caused partial deletion of the short intracellular domain of the fusion protein, most likely compromising efficient viral budding. Moreover, in the hemagglutinin gene of a strain showing strongly reduced hemadsorption, 20 clustered A to G mutations, resulting in 16 amino acid changes, were detected. This hypermutation might be due to unwinding modification of a part of the MV RNA genome accidentally present in a double-stranded form. Finally, we classified four lytic and seven persistent MV strains on the basis of their sequences. Surprisingly, the four lytic viruses considered belong to the same class. The persistent viruses form more loosely defined groups, which all differ from the vaccine strain Edmonston.

Amino Acid Sequence↗

PubMed1989

Nucleotide sequence of the matrix, fusion and putative SH protein genes of mumps virus and their deduced amino acid sequences.

cDNA clones representing the M, F and a putative SH gene of the SBL strain of mumps virus have been prepared and their nucleotide sequence determined. The M gene of mumps virus appears to contain 1253 nucleotides and codes for a protein of 375 amino acid residues (Mr 41,589). The protein is hydrophobic and the deduced amino acid sequence shows homologies with those of other paramyxoviruses. The F gene of the SBL strain was compared to that of the RW strain [Waxham et al. (1987) Virology 159, 381-388]. The F gene is 1727 nucleotides long and codes for a protein of 538 amino acids (Mr 58,789). There are substantial variations between the F gene sequences of various mumps virus strains. The F gene is followed by a small (315 nt) transcription unit which contains an open reading frame of 57 amino acids encoding a very hydrophobic protein (Mr 6712). This may be similar to the SH gene of SV5, although there appears to be no sequence homology between the SV5 SH protein and the putative SH protein of mumps virus. A physical and transcription map of mumps virus indicates the gene order to be 3'-N-P-M-F-SH-HN, similar to that of other paramyxoviruses and SV5 in particular.

Amino Acid Sequence↗

PubMed1989

Examination of eight cases of multiple sclerosis and 56 neurological and non-neurological controls for genomic sequences of measles virus, canine distemper virus, simian virus 5 and rubella virus.

In situ hybridization studies have been carried out on brain samples from eight cases of multiple sclerosis (MS) and 56 non-neurological and neurological controls, using single-stranded 35S-labelled RNA probes prepared against genomic RNA sequences of measles virus, canine distemper virus, rubella virus and simian virus 5. Foci of hybridization were found using probes against the measles virus nucleocapsid protein (N), phosphoprotein and fusion protein gene sequences in two of the MS cases, and also in one control, a case of disseminated cytomegalovirus infection with spinal cord necrosis. This result was confirmed using biotinylated probes prepared against the measles virus N genomic sequence. No hybridization was found in any of the MS or control cases using any of the other viral genome-specific probes.

Astrocytoma↗

PubMed1988

Restricted synthesis of the fusion protein of measles virus at elevated temperatures.

The elevation of culture temperatures from 35 degrees C to 39 degrees C led to the cessation of the synthesis of the fusion (F) protein of measles virus. This effect was caused by inhibition of the translation of the corresponding mRNA rather than by a decrease in the synthesis or stability of the mRNA or by increased degradation of the F protein at elevated temperatures. The haemagglutinin (H) and F mRNAs were distributed differently in gradients on which polysomes were fractionated. The H mRNA was present almost exclusively in the largest polysomes whereas the F mRNA was more evenly distributed over large and small polysomes. The distribution was not affected by a temperature shift. The inhibition of F protein synthesis thus appeared to be related to a cessation of elongation of the nascent polypeptide chain rather than to a defect in initiation of the translation of the F mRNA at 39 degrees C.

Animals↗

PubMed1988

Nucleotide sequence of the gene encoding the matrix protein of a recent measles virus isolate.

The sequence of the M gene of the Hu2 strain of measles virus has been determined. In the coding region of the gene, six nucleotide replacements had occurred with respect to the sequence of the M gene of the Edmonston strain. Two of these were silent and only four led to amino acid replacements in the protein sequence even though in SDS-PAGE the mobility of the protein would indicate an Mr increase of 2000. No changes were observed in the 5' untranslated regions of the gene. Two changes were observed in the 3' untranslated region of the gene. The sequences are compared to those recently published for subacute sclerosing panencephalitis viruses.

Amino Acid Sequence↗

PubMed1987

Identification of negative strand and positive strand RNA of canine distemper virus in animal tissues using single stranded RNA probes.

In this report, we describe a technique for identifying negative strand (genome) and positive strand (messenger) RNA of canine distemper virus (CDV) in dog tissues by using single stranded RNA probes. Plasmids (pSP64-P and pSP65-P) which contain insert DNA corresponding to the P gene of CDV were transcribed by SP6 polymerase in the presence of radioisotope to produce radiolabeled single stranded RNA probes. RNA transcribed from pSP65-P is complementary to the negative strand (genome) and RNA produced from pSP64-P is complementary to the positive strand (message) of CDV. The binding specificity of the single stranded RNA probes was determined on Northern-blots. The use of these RNA probes in hybridization assays resulted in greater sensitivity and specificity than that obtained from double stranded DNA probes (either whole plasmids or purified insert DNA) which were labeled by the nick translation reaction. We also describe the making of single stranded DNA probes by reverse transcription labeling of complementary RNA. The complementary RNA was produced by the transcription of cloned DNA (pSP64-P and pSP65P). Single stranded RNA probes and single stranded DNA probes were similar in sensitivity. The single stranded RNA and DNA probes were applied to ethanolacetic acid fixed tissue sections from dogs infected with CDV-A75/17. We used 32P-labeled probes in tissue hybridizations and 35S-labeled probes in in situ hybridizations to identify negative and positive stranded CDV RNA. In this report we demonstrate that single stranded RNA and DNA probes can be used successfully in tissue hybridization and in situ hybridization assays to study viral expression in this virus-host system.

Animals↗

PubMed1987

The nucleotide sequence of the gene encoding the F protein of canine distemper virus: a comparison of the deduced amino acid sequence with other paramyxoviruses.

The nucleotide sequence of the gene encoding the fusion protein of canine distemper virus was determined from cDNA clones derived from virus genome RNA and poly(A)+ RNA extracted from infected cells. The mRNA encoding the F protein is about 2300 nucleotides in length including the 3' poly(A) tail. There is a large open reading frame from nucleotides 86 to 2071 which begins at the first AUG codon in the F mRNA. This reading frame encodes a protein of 662 amino acid residues with a calculated mol. wt. of 73001. The first major hydrophobic domain in the amino acid sequence of the deduced protein (residues 104 to 130) may represent all or part of a signal sequence for cleavage of the N terminal part of the F2 protein. There are four potential N glycosylation sites in the F protein located within the F2 part of the molecule or the putative signal sequence, and one in the F1 portion. A second hydrophobic region corresponds to the proteolytic cleavage site which generates the F2 and F1 subunits. This stretches from residue 225 to 262 and the N terminal part of the F1 protein shows sequence conservation with the other paramyxoviruses. A third major hydrophobic domain near the C terminus of the F protein probably represents the membrane anchor for the F protein (residues 602 to 630). The F1 proteins of six paramyxoviruses are compared and shown to have substantial conservation of those residues important in the maintenance of tertiary structure of this protein.

Amino Acid Sequence↗

PubMed1987

Humoral immune response in dogs with old dog encephalitis and chromic distemper meningo-encephalitis.

The humoral immune response in sera and cerebrospinal fluids (CSFs) of dogs with various forms of canine distemper virus (CDV)-induced encephalitis was assessed by immunoprecipitation of radiolabelled nucleocapsid, phosphoprotein, membrane (M), haemagglutinin and fusion proteins. Sera from vaccinated dogs and hyperimmune sera contained antibodies to all the above antigens. In two cases of old dog encephalitis the sera and CSFs showed a restricted response to the M protein of CDV, whilst in three other cases of old dog encephalitis, two cases of chronic distemper (meningo-) encephalitis and experimentally induced encephalitis the humoral immune response appeared to be directed primarily to the nucleocapsid, phosphoprotein and the M protein but not the haemagglutinin or fusion proteins. Precipitation of the M protein by most of the sera was observed only when the antigen had been prepared by in vitro translation.

Animals↗

PubMed1987

Selective inhibition of translation of the mRNA coding for measles virus membrane protein at elevated temperatures.

The elevation of culture temperatures of C6 cells that were persistently infected with the Lec strain of the subacute sclerosing panencephalitis (SSPE) virus (C6/SSPE) resulted in immediate selective inhibition of membrane (M) protein synthesis. This phenomenon was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total cytoplasmic lysates and immunoprecipitation with monoclonal antibody against the M protein in short-time labeling experiments. The synthesis of various viral mRNAs in the presence of actinomycin D decreased gradually at similar rates after a shift to 39 degrees C. No specific disappearance of the mRNA coding for the M protein was observed when viral RNAs isolated from the infected cells were compared before and after a shift up by Northern blot analysis. Results of pulse-chase experiments did not show any significant difference in M protein stability between 35 and 39 degrees C. This rapid block of M protein synthesis was observed not only in Vero cells that were lytically infected with plaque-purified clones from the Lec strain, clones isolated from C6/SSPE cells and the standard Edmonston strain of measles virus but also in CV1, MA160, and HeLa cells that were lytically infected with the Edmonston strain. Poly(A)+ RNAs that were extracted from C6/SSPE cells before and after a shift to 39 degrees C produced detectable phospho, nucleocapsid, and M proteins in cell-free translation systems at 32 degrees C. Even higher incubation temperatures did not demonstrate the selective depression of M protein synthesis described above in vitro. All these data indicate that M protein synthesis of measles virus is selectively suppressed at elevated temperatures because of an inability of the translation apparatus to interact with the M protein-encoded mRNA.

Animals↗

PubMed1986

Characterization of clones for the sixth (L) gene and a transcriptional map for morbilliviruses.

cDNA clones of the largest RNA transcript of the canine distemper and measles morbilliviruses were characterized. This presumably codes for the L protein of these viruses. mRNA 4 was identified as coding for the haemagglutinin protein of measles virus. From an analysis of readthrough transcripts representing tandem copies of two or three genes we established a transcriptional map and the gene order on the negative strand genome of the morbilliviruses to be 3'-N-P + C-M-F-H-L-5'. The data exclude the presence of small intervening genes between the six major genes of morbilliviruses and indicate the gene order to be similar to that of Sendai virus and different from that of simian virus 5.

Cloning, Molecular↗

PubMed1985

cDNA cloning of the messenger RNAs of five genes of canine distemper virus.

Messenger RNAs from Vero cells infected with the Onderstepoort strain of canine distemper virus (CDV) were cloned into the PstI site of plasmid pAT153. Total polyadenylated RNA was used and resulting clones were screened with 32P-labelled cDNA probes from infected and mock-infected cells. The virus specificity of the clones was proven by Northern blot hybridization and by ability to select radioactive virus mRNAs labelled in vivo in the presence of actinomycin D. Clones from the N, P and M genes of CDV were identified by hybrid select translation; clones which presumably represent the H and F genes were also obtained. The clones allowed a designation of the major viral mRNA bands. Bicistronic mRNAs were identified, and their selection by various clones suggests a gene order of 3'-N-P-M-70K-65K-L-5' for this virus.

Cloning, Molecular↗

PubMed1985

cDNA cloning of the nucleocapsid and nucleocapsid-associated protein genes of mumps virus.

cDNA clones of the mumps virus N and P messenger RNAs were isolated from an infected cell cDNA library. The N and P clones selected the two predominant polyadenylated RNAs found in mumps virus-infected cells with mol. wt. of 0.69 X 10(6) and 0.51 X 10(6), respectively. In addition, clones of the P gene hybridized to and selected mRNAs of higher mol. wt. probably representing polycistronic transcripts of the mumps genome. Hybrid-select translation experiments confirmed the specificity of the clones as representing the nucleocapsid (N) and nucleocapsid-associated protein (P) genes.

Capsid↗

PubMed1985

The generation of small-plaque mutants during undiluted passage of canine distemper virus.

A culture of Vero cells persistently infected with undiluted-passage, large-plaque canine distemper virus was found to release small-plaque virus (SPV). This suggested that SPV could be generated by large-plaque virus (LPV). However, attempts to induce small-plaque mutants from LPV with 5-fluorouracil resulted in the production of virus that expressed a variable plaque type and induced a spectrum of disease in hamsters. In contrast, small-plaque mutants, shown to arise during undiluted passage of LPV, retained their small-plaque characteristic and resembled our original SPV isolate in their cytopathogenicity, immunogenicity, and neurovirulence for hamsters.

Animals↗

PubMed1985

A survey of serum antibodies to eight common viruses in psychiatric patients.

Serum antibody titres to eight neurotropic viruses were measured by enzyme immunoassay in 450 psychiatric in-patients and 143 controls. A seasonal variation in schizophrenic births was observed, with a peak incidence between March and April. Both herpes simplex virus and cytomegalovirus antibody titres correlated with age and, when this was controlled for, no significant differences emerged between any patient group and the controls. Mumps antibody titres were significantly lower in patients with mental subnormal and neurosis or personality disorder; measles and rubella antibody titres were lower in male but not female mentally handicapped patients; males had lower antibody titres to mumps, cytomegalovirus and Epstein-Barr virus than females in all groups. A decrease in mumps antibody titres was also found in schizophrenics if the medication factor was excluded. These low antibody titres may indicate an impaired immune response. Thus perinatal or childhood subclinical viral infections of the central nervous system, particularly of mumps, might lead to a range of possible psychiatric outcomes in later life.

Adolescent↗