Laura L Hermann

University of Manitoba, Winnipeg, Manitoba, Canada

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Publications (6)17.26 Total impact

  • Jieyuan Jiang, Laura Hermann, Kevin M Coombs
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    ABSTRACT: We previously described isolation of a potentially new reovirus strain from the central nervous system of an 8-week-old female infant with a history of active varicella, oral thrush, hypoalbuminemia, intermittent fevers, diarrhea and feeding intolerance [Hermann et al., Ped. Inf. Dis J. 23, 373 (2004)]. This reovirus strain was tentatively identified as a member of the serotype 2 group by virus neutralization and RNA-gel electrophoresis studies and has been named type 2 Winnipeg (T2W). For this study we determined the nucleotide sequences of the T2W S1, S2, S3 and S4 genome segments to allow molecular comparison with other reoviruses. Comparative segment alignments of T2W S1 gene sequence with other reovirus S1 sequences showed T2W belongs to reovirus serotype 2. T2W S1 is most similar to the S1 genes of reovirus strains T2/Human/Netherlands/1,984 and T2/Human/Netherlands/1,973 with nucleotide identity >93%. The T2W S2 gene showed highest identity to reovirus T1 Lang S2 (approximately 75%). The T2W S3 gene showed highest identity to the S3 gene of T3/Human/Netherlands/1,983 (approximately 74%), and the T2W S4 gene showed highest identity to the T2 Jones S4 gene (approximately 73%). Pairwise protein comparisons between T2W sigma proteins and all available reovirus sigma proteins ranged from <21% identity for the sigma1 comparisons to more than 95% identity for sigma2 comparisons. The predicted T2W sigma1, sigma2 and sigma3 protein sequences were confirmed by mass spectrometry.
    Virus Genes 11/2006; 33(2):193-204. · 1.77 Impact Factor
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    Laura L Hermann, Kevin M Coombs
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    ABSTRACT: The role of reoviruses in human disease is uncertain. Most identified cases are sporadic and asymptomatic or produce minor upper respiratory or gastrointestinal symptoms. In November 1997, a reovirus was isolated from the cerebrospinal fluid of a severe combined immune deficient infant in Winnipeg, Manitoba. RNA characterization and sequencing studies demonstrated this reovirus isolate to be unique. Thus, the virus was named Type 2 Winnipeg (T2W). Mycophenolic acid (MPA), a drug primarily used as an immunosuppressive agent, was assessed in the capacity to inhibit T2W viral growth. The effects of MPA on viral growth were determined by plaque reduction assays. Cells were treated with different MPA concentrations, infected with T2W and incubated at 37 degrees C for 0 h to 72 h. Virus titres were determined and compared with untreated controls. Production of infectious T2W progeny decreased more than 99% at 3 microg/mL MPA compared with untreated controls. Inhibition was not caused by cell toxicity because there was no difference in cell viability. The 50% cell toxic dose was 30 microg/mL MPA. MPA was able to inhibit viral growth of the novel reovirus T2W. Although MPA is usually used as an immunosuppressive agent, and despite the fact that T2W was isolated from an immunocompromised patient, these results suggest that MPA could have been used as a possible treatment at subimmunosuppressive doses. Animal studies to better define the antiviral and immunosuppressive activities of MPA (and its prodrug mycophenolate mofetil) appear warranted.
    The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale / AMMI Canada 10/2004; 15(5):261-5. · 1.02 Impact Factor
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    ABSTRACT: Avian reoviruses (ARV) are economically important pathogens, especially in the poultry industry, where they cause viral arthritis and tenosynovitis. Mycophenolic acid (MPA) is an inhibitor of inosine monophosphate dehydrogenase (mainly used clinically for immunosuppression) that inhibits the replication of several viruses. We demonstrate in this study that MPA also is capable of inhibiting ARV replication in QM5 quail fibrosarcoma cells. The selectivity index of MPA in QM5 cells was determined as approximately 41. Concentrations of > or =3 microg/ml MPA inhibited infectious ARV progeny production in QM5 cells by more than 100-fold. Inhibition of ARV replication also was seen in other cell lines, including HD-11 and Vero. Addition of exogenous guanosine to MPA-treated ARV-infected QM5 cells restored viral replicative capacity to nearly normal levels.
    Antiviral Research 10/2004; 64(1):55-61. · 3.93 Impact Factor
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    Laura L Hermann, Kevin M Coombs
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    ABSTRACT: Mycophenolic acid (MPA), an inhibitor of IMP dehydrogenase, inhibits reovirus replication and viral RNA and protein production. In mouse L929 cells, antiviral effects were greatest at 30 microg of MPA/ml. At this dosage, MPA inhibited replication of reovirus strain T3D more than 1,000-fold and inhibited replication of reovirus strain T1L nearly 100-fold, compared to non-drug-treated controls. Genetic reassortant analysis indicated the primary determinant of strain-specific differences in sensitivity to MPA mapped to the viral M1 genome segment, which encodes the minor core protein mu2. MPA also inhibited replication of both strains of reovirus in a variety of other cell lines, including Vero monkey kidney and U373 human astrocytoma cells. Addition of exogenous guanosine to MPA-treated reovirus-infected cells restored viral replicative capacity to nearly normal levels. These results suggest the mu2 protein is involved in the uptake and processing of GTP in viral transcription in infected cells and strengthens the evidence that the mu2 protein can function as an NTPase and is likely a transcriptase cofactor.
    Journal of Virology 07/2004; 78(12):6171-9. · 5.08 Impact Factor
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    ABSTRACT: An 8-week-old female infant presented with a history of active varicella complicated by Escherichia coli sepsis, oral thrush, hypoalbuminemia, intermittent fevers, diarrhea and feeding intolerance. Rhesus monkey kidney cells inoculated with cerebrospinal fluid revealed reovirus-like particles by electron microscopy. Virus neutralization and RNA-gel electrophoresis studies identified the isolated pathogen as reovirus serotype 2. This report represents one of only a few to isolate reovirus from the central nervous system in humans.
    The Pediatric Infectious Disease Journal 05/2004; 23(4):373-5. · 3.57 Impact Factor
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    ABSTRACT: Freon 113 (Freon) is an essential component used in some viral purification methods to separate virus from infected cell debris. With its environmental and toxic hazards, Freon's availability is limited and more tightly regulated. Several organic solvent substitutes were selected to identify a suitable Freon replacement for the purification of both cultivable reovirus and fastidious calicivirus. Reovirus was extracted from tissue cultured cells with each solvent tested and purified in cesium chloride gradients by standard techniques. Purified virions were analyzed for conservation of physical and biological properties by morphological examination and infectivity studies. The purification of calicivirus nucleic acid from stool samples using selected solvents was also examined. Solvent-extracted calicivirus RNA was reverse transcribed and quantified by polymerase chain reaction amplification of a standard diagnostic 117 bp amplicon. These studies indicated that Vertrel XF (a newly developed environmentally friendly Freon substitute) and a 7:3 mixture of isopentane/1-chlorobutane are suitable replacements. Considerations of flammability and ease of use suggest that Vertrel XF is the preferred choice as a Freon substitute for the purification of these non-enveloped viruses.
    Journal of Virological Methods 11/2000; 90(1):59-67. · 1.90 Impact Factor