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H Huismans

Publications and source records attributed to H Huismans.

At least 55 records · Page 3Linked to original sources
PubMed1990

Characterization and cloning of the African horsesickness virus genome.

The dsRNA profiles of all nine African horsesickness virus (AHSV) serotypes were compared by agarose gel electrophoresis and PAGE. The agarose profiles were identical, but a unique profile was obtained for each of the nine serotypes by PAGE. Nine of the 10 dsRNA genome segments of AHSV-3 were cloned and the clones were used in dot-spot and Northern blot hybridization experiments to determine intra- and inter-serogroup nucleic acid similarities. Segments 1, 3, 4, 5, 7 and 8 were highly conserved in the AHSV serogroup and no genetic relationship with any of the other orbiviruses was observed. Of these segments 3, 5 and 8 showed the largest degree of cross-hybridization to the cognate genes of all the serotypes. These clones did not cross-hybridize to other orbiviruses such as epizootic haemorrhagic disease virus, bluetongue virus or equine encephalosis virus and are therefore recommended for use as group-specific probes for the identification of the AHSV serogroup. Genome segments 6 and 10 showed an intermediate degree of conservation, whereas segment 2 is serotype-specific and therefore probably codes for the outer capsid protein VP2.

African Horse Sickness Virus↗
PubMed1989

The characterization of equine encephalosis virus and the development of genomic probes.

Equine encephalosis virus (EEV) is an orbivirus associated with a peracute illness of horses in southern Africa. The virus has now been partially purified for the first time and characterized on a molecular level. The virion is composed of 10 dsRNA segments and a protein capsid consisting of at least seven structural proteins that vary in Mr from 36,000 to 120,000. Partial clones of six of the dsRNA segments of EEV serotype Cascara were obtained and analysed for possible use as serotype-specific or group-specific probes in the detection of EEV dsRNA. Cloned fragments of genome segments 3, 8 and 10 were found to show high conservation of these segments, hybridizing to dsRNA from the six EEV serotypes under conditions that indicated more than 90% sequence homology. The genome segment 2-specific probe did not hybridize with dsRNA from any of the other EEV serotypes, suggesting that this segment encodes the serotype-specific antigen of EEV. Cross-hybridization of probes from genome segments 3 and 5 with dsRNA from bluetongue virus (BTV), epizootic haemorrhagic disease virus (EHDV) and African horse sickness virus (AHSV) indicated that EEV is more closely related to BTV and EHDV than to AHSV. Both probes can be used to distinguish between EEV and AHSV dsRNA.

African Horse Sickness↗
PubMed1988

[Demodex folliculorum].

The author reports on Demodex folliculorum ("hair follicle mite"), a frequent and widespread parasite. These mites are found in hair follicles of eyelashes in particular. In ophthalmology they are responsible for chronic eczematous blepharitis ("blepharitis acarica") with trichiasis and madarosis. Therapy is unsatisfactory. The author has now discovered that isoptocarbachol 3% eyedrops successfully combat Demodex folliculorum. The solution was first tested experimentally on house flies (Musca domestica) and was later used to treat patients affected with the parasite: a cotton bud impregnated with this parasympathomimetic (anticholinesterase) drug was applied to the border of the eyelids several times.

Adult↗
PubMed1988

In vitro transcription and translation of bluetongue virus mRNA.

Fractionation of in vitro transcribed bluetongue virus (BTV) mRNA by agarose gel electrophoresis resulted in the separation of eight of the 10 species. The relative molar ratio of the mRNAs confirmed that mRNA 5 was transcribed more frequently than would be predicted from the size of the S5 genome segment, while mRNA 10 was transcribed less frequently. In vitro translation of unfractionated BTV mRNAs resulted in the synthesis of the seven known structural proteins (P1 to P7) and two known non-structural proteins (NS1 and NS2). Two additional non-structural proteins (NS3 and NS3A) with Mr of 28K and 25K respectively were identified. The protein coding assignments for the medium- and small-sized double-stranded RNA genome segments of BTV serotype 10 were found to correspond to those reported for BTV-1 and BTV-17. The peptide maps of NS1, NS2, NS3 and NS3A synthesized in vitro corresponded to those of their counterparts synthesized in infected cells. Protein NS3A appeared to be a truncated form of NS3, since its peptide map completely overlapped that of NS3. Proteins NS3 and NS3A were present in very small amounts in the soluble fraction of the cytoplasm of infected cells, and were synthesized in variable amounts in vitro, whereas the other nine viral proteins were synthesized in constant molar ratios. A difference in the relative molar ratios in which some of the BTV proteins were synthesized in vitro and in vivo was observed. In vivo, protein NS1 was translated in the largest amount but in vitro, NS2 was the most efficiently translated protein. Conversely, protein P6 was translated much more efficiently in vitro than in vivo.

Bluetongue virus↗
PubMed1987

The genetic relatedness of a number of individual cognate genes of viruses in the bluetongue and closely related serogroups.

Genome segments 2, 4, 6, 7, 8, 9, and 10 of bluetongue virus (BTV) serotype 10 were cloned in pBR322. The 2926-bp S2 gene, which codes for the serotype-specific antigen, was cloned as two overlapping 2.4-kb inserts. The relatedness of cognate S2 genes among different isolates of BTV10 was investigated by hybridization, restriction enzyme mapping, and sequencing of the terminal ends. Hybridization under high stringency conditions indicated a genetic diversity between isolates of BTV10 from South Africa and the United States. This was confirmed by a comparison of the restriction map of the cloned S2 gene of a BTV10 isolate from South Africa to that of the S2 gene of the BTV10 strain of the United States which has been cloned and sequenced by Purdy et al. (1985). The part of the genome that was sequenced indicated, however, that this variation was confined to an approximately 10% sequence divergence in the coding region. Very few of the nucleotide substitutions resulted in an amino acid change. The genetic variation of cognate BTV genes within the BTV serogroup as well as among different members of closely related serogroups was also investigated. DNA probes from cloned BTV10 segments were hybridized to dsRNA from 24 different BTV serotypes. Genome segments S2 and S6 were found to be almost equally serotype specific. The stringency of the wash solutions after hybridization can be manipulated to determine an order of relatedness of different cognate genes. This was illustrated by the hybridization of a sensitive RNA probe of S7 to different BTV serotypes as well as to dsRNA from closely related orbiviruses. The results confirmed a relatedness between BTV and members of the epizootic hemorrhagic disease virus (EHDV) serogroups.

Amino Acid Sequence↗
PubMed1987

A comparison of different cloned bluetongue virus genome segments as probes for the detection of virus-specified RNA.

The seven largest double-stranded (ds) RNA genome segments of bluetongue virus (BTV) serotype 4 as well as genome segment 8 of BTV10 have been cloned into pBR322. The length of the cloned genes indicates that, with the exception of genome segment 1, the entire gene has been cloned in each case. A method is described for isolating different sized cDNA transcripts on alkaline sucrose gradients with very good recovery. The eight cloned genes were compared as 32P-labeled probes for the detection of dsRNA from 21 different BTV serotypes. The S1, S3, S4, S5, and S8 genes were identified as being highly conserved. Of these, S5, which codes for nonstructural protein NS1, gave the best hybridization signal with all the dsRNA isolates. All the probes hybridized significantly weaker with the dsRNA of BTV isolates from Australia and Pakistan than with dsRNA from other serotypes. Genome segment 7, which codes for the group-specific antigen P7, was not highly conserved. Even more variation was shown by genome segment 6 which codes for outer capsid polypeptide P5. S2 which codes for protein P2 is the obvious choice for a serotype-specific probe. Hybridization of this probe with dsRNA from other serotypes reflects the cross-neutralization between BTV4 and these serotypes. The hybridization results can also be used to define the relatedness of BTV4 to other serotypes. None of the probes hybridized with dsRNA from any of the other orbiviruses investigated.

Bluetongue virus↗
PubMed1987

Isolation of a capsid protein of bluetongue virus that induces a protective immune response in sheep.

A method to purify the neutralization specific antigen of bluetongue virus P2 in large amounts has been developed. The purified protein is free from virus-specified or cellular contaminants and its immunological specificity has been preserved. The purification is based on the observation that protein P2 can be dissociated from the virion by treatment with monovalent or divalent salts. The salt concentration required to solubilize the outer capsid proteins is pH dependent and in general decreases with a decrease in pH. P2 purified by extraction from polyacrylamide gels does not induce immune-precipitating or neutralizing antibodies. The response against P5, on the other hand, is much less conformational dependent and P5 purified from gels readily induces P5-precipitating antibodies in rabbits. These antibodies do not neutralize the virus. Purified P2, immunoabsorbed with anticore serum to remove trace amounts of P7, was injected into sheep. An initial dose of 50 micrograms of P2 was sufficient to induce P2-precipitating antibodies as well as neutralizing and hemagglutination-inhibiting antibodies. These sheep were fully protected against challenge with a virulent strain of the same BTV serotype. Lower doses of P2 still provided a significant level of protection even though no neutralizing antibodies could be detected.

Animals↗
PubMed1987

Uncoating of parental bluetongue virus to core and subcore particles in infected L cells.

A study was made of the fate of parental bluetongue virus (BTV) in infected cells. Within the first hour after infection, the BTV particles are converted to core particles with the loss of major capsid polypeptides P2 and P5. The particles are able to synthesize mRNA in vitro in a transcription reaction characterized by a temperature-dependent inhibition at high core concentrations. From about 6 hr after infection a second uncoating event is observed in which the 470 S core particles are converted to 390 S subcore particles. These particles are morphologically strikingly different from core particles and have a skeletonlike structure with a hexagonal profile and a side to side diameter of 40 nm. These subcore particles contain only one major structural protein, P3, and three minor proteins, P1, P4, and P6. They do, however, contain all 10 double-stranded RNA segments. The results suggest that the characteristic capsomeres on the surface of core particles are composed mainly of P7, the soluble group-specific antigen of BTV. The subcore particles are stable only at very low salt concentrations. Under these conditions no transcriptase activity can be demonstrated.

Animals↗
PubMed1987

[Subretinal cysticercosis].

This paper communicates the history of a case of subretinal cysticercosis in the left eye of a 73-year-old female patient. The only subjective complaints were slightly blurred vision in the affected eye. Serological findings in the blood (Agar-Gel precipitation; IFAT; ELISA) and the aqueous humor were negative. However, according to the literature false-negative serological findings are not uncommon. A stool examination for worm eggs or tapeworm segments was also negative. The remaining lab findings, including hemogram and immunoelectrophoresis, were also normal. Neurocysticercosis was ruled out by clinical and roentgenologic (CCT) diagnosis. As the patient declined treatment with praziquantel, a modern treatment for tapeworm, photocoagulation of the cysticercus was performed at two sittings, first peripheral demarcation and subsequently central coagulation.

Aged↗
PubMed1987

In vitro phosphorylation and purification of a nonstructural protein of bluetongue virus with affinity for single-stranded RNA.

A phosphorylated, nonstructural protein of bluetongue virus, NS2, is synthesized throughout the replication cycle in comparatively large amounts. The protein was detected in both the soluble and particulate fraction of the cytoplasm of infected cells. The particulate NS2 could be solubilized in 0.5 M NaCl. It was found that NS2 in the particulate fraction and immunoprecipitates of NS2 from the soluble protein fraction could be phosphorylated in vitro. It is not known whether the kinase involved is of cellular or viral origin, but after purification of NS2 by affinity chromatography on poly(U)-Sepharose it could still by phosphorylated in vitro without the addition of exogenous protein kinase. The affinity of NS2 for nucleic acid was also investigated. The protein was found to bind to single-stranded RNA. In the presence of purified bluetongue virus mRNA, NS2 formed a complex with an estimated S value of about 22S.

Animals↗
PubMed1987

The identification of factors capable of reversing the core-mediated inhibition of the bluetongue virus transcriptase.

The in vitro transcription reaction of bluetongue virus (BTV) is characterized by a core-mediated, temperature-dependent inhibition at high core concentrations and temperatures (Van Dijk & Huismans, 1980; Huismans, Van Dijk & Els, 1987a). It has been found that this inhibition is reversible and that an inactivated transcriptase reaction mixture can be reactivated by lowering the temperature of the reaction from 37 degrees C to 28 degrees C. In the same way it is possible to inactivate a reaction by increasing the incubation temperature from 28 degrees C to 37 degrees C. It was also found that the inhibition is counteracted by the addition of sucrose or glycerol. At relatively low core concentrations and in the presence of sucrose it is possible to obtain conditions under which transcription at 37 degrees C is more efficient than at 28 degrees C. The latter conditions probably reflect much better the in vivo temperature optimum for the BTV transcriptase than the in vitro conditions at very high core concentrations.

Bluetongue virus↗
PubMed1986

[Acute chorioretinitis caused by Listeria monocytogenes].

The present paper reports on a case of acute chorioretinitis caused by Listeria monocytogenes in a 16-year-old girl. The inflammatory process was brought to a standstill by antibiotic therapy in combination with systemic cortisone administration. Final visual acuity in the affected eye was 0.8-1.0.

Adolescent↗
PubMed1985

[Recurrent iritis as the initial symptom in plasmacytoma (IgG type)].

The author presents a case report on a 47-year-old man with recurrent serofibrinous iritis. As a result of intensive investigations an IgG-type myeloma was finally diagnosed with the aid of serum electrophoresis, immunoelectrophoresis, and sternal puncture. Apart from ocular symptoms of acute iritis all findings were normal. General clinical findings were also normal and the patient was subjective free of complaints.

Bone Neoplasms↗
PubMed1985

Immune response against the purified serotype specific antigen of bluetongue virus and initial attempts to clone the gene that codes for the synthesis of this protein.

Sheep were injected with different amounts of purified protein P2 of bluetongue (BT) virus (BTV). About 3 X 50 mcg was required for the induction of neutralizing antibodies. Sheep injected with 3 X 10 mcg were, however, still largely protected when challenged with virulent virus. This has suggested the possibility of using P2 as a subunit vaccine and initiated an investigation of the possibility of synthesizing P2 by DNA-recombinant technology. In order to clone the gene that codes for the synthesis of P2 both the "shotgun" approach with unfractionated dsRNA and cloning of isolated segment 2 were investigated. The basic approach was to convert the dsRNA to DNA which was cloned into the Pst 1 site of E. coli plasmid pBR322. The largest BTV-specific insert that was obtained in the initial experiments was just more than 2,000 base pairs long. The largest insert obtained when isolated segment 2 dsRNA was cloned was about 1,200 base pairs which represents about 1/3 of the P2 gene.

Antibodies, Viral↗