Vicky van Santen | Auburn University (original) (raw)

Papers by Vicky van Santen

Avian Diseases, Apr 1, 2001

In this study, a total of nine chicken samples obtained from two broiler flocks in Oita and Totto... more In this study, a total of nine chicken samples obtained from two broiler flocks in Oita and Tottori prefectures in 2020 were examined for Chicken anemia virus (CAV) infection. The samples were collected from clinically suspected flocks and diseased chickens. The CAV genome was detected in all nine samples tested by real-time PCR. Phylogenetic analyses and sequence comparisons of the full-length VP1 gene sequences indicated that all the Japanese CAV strains obtained in this study formed a similar cluster of genotype III and shared high nucleotide (99.62-100%) identity. The current Japanese CAV strains were closely related to Chinese CAV strains but not related to vaccine strains. One positive selection site of VP1 was detected among the Japanese CAV strains.

Infection and Immunity, Feb 1, 2000

Mycoplasma gallisepticum, the cause of chronic respiratory infections in the avian host, possesse... more Mycoplasma gallisepticum, the cause of chronic respiratory infections in the avian host, possesses a family of M9/pMGA genes encoding an adhesin(s) associated with hemagglutination. Nucleotide sequences of M9/ pMGA gene family members indicate extensive sequence similarity in the promoter regions of both the transcribed and silent genes. The mechanism that regulates M9/pMGA gene expression is unknown, but studies have revealed an apparent correlation between gene expression and the number of tandem GAA repeat motifs located upstream of the putative promoter. In this study, transposon Tn4001 was used as a vector with the Escherichia coli lacZ gene as the reporter system to examine the role of the GAA repeats in M9/pMGA gene expression in M. gallisepticum. A 336-bp M9 gene fragment (containing the GAA repeat region, the promoter, and the translation start codon) was amplified by PCR, ligated with a lacZ gene from E. coli, and inserted into the Tn4001-containing plasmid pISM2062. This construct was transformed into M. gallisepticum PG31. Transformants were filter cloned on agar supplemented with 5-bromo-4-chloro-3-indolyl-␤-D-galactopyranoside (X-Gal) to monitor lacZ gene expression on the basis of blue/white color selection. Several cycles of filter cloning resulted in cell lineages in which lacZ gene expression alternated between the On and Off states in successive generations of progeny clones. The promoter regions of the M9-lacZ hybrid genes of individual progeny clones were amplified by PCR and sequenced. The only differences between the promoter regions of the blue and white colonies were in the number of GAA repeats. Clones that expressed lacZ had exactly 12 tandem copies of the GAA repeat. Clones that did not express lacZ invariably had either more than 12 (14 to 16) or fewer than 12 (5 to 11) GAA repeats. Southern analysis of M. gallisepticum chromosomal DNA confirmed that the phase-variable expression of the lacZ reporter gene was not caused by Tn4001 transposition. These data strongly indicate that changes in the length of the GAA repeat region are responsible for regulating M9/pMGA gene expression.

Journal of Virology, Aug 1, 2008

We previously showed that herpes simplex virus type 1 (HSV-1) immediate-early (IE) protein ICP27 ... more We previously showed that herpes simplex virus type 1 (HSV-1) immediate-early (IE) protein ICP27 can posttranscriptionally stimulate mRNA accumulation from a transfected viral late gene encoding glycoprotein C (gC) (K. D.

Avian Diseases, Sep 1, 2012

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Veterinary Pathology, 2006

Glanzmann thrombasthenia (GT) is an inherited, intrinsic platelet defect characterized by a quant... more Glanzmann thrombasthenia (GT) is an inherited, intrinsic platelet defect characterized by a quantitative or qualitative change in the platelet glycoprotein complex IIb-IIIa (integrin a IIb b 3). The subunits are encoded by separate genes and both subunits must be expressed for a stable complex to form on the platelet surface; therefore, a defect in either gene can result in GT.

Our previous genetic characterization of chicken anemia virus (CAV) in commercial broiler chicken... more Our previous genetic characterization of chicken anemia virus (CAV) in commercial broiler chickens in Alabama revealed a previously undetected polymorphism: a glutamine codon at VP1 position 22, in 7 of the 14 sequences. The novel glutamine codon was always found in association with a VP1 "hypervariable region" identical to CAV field isolates that replicate poorly in culture. The complete genome of CAV73, representative of the sequences with the novel polymorphism, was generated from cloned polymerase chain reaction (PCR) fragments amplified directly from naturally infected tissues. CAV73 had been detected in 31-day-old broilers submitted for examination for reasons unrelated to anemia. After electroporation of the cloned genomes into MDCC-CU147 lymphoblastoid cells, the regenerated CAV caused the culture to fail within 9 days, and the medium contained 5 x 106 TCID50 CAV/ml. Use of MDCC-CU147 cells was essential, as identical electroporation of MDCC-MSB1 cells failed to generate CAV able to destroy the culture within 8 wk. Regenerated CAV73 produced anemia and severe lymphocytic depletion of the thymus when inoculated into susceptible 3-day-old chickens and was reisolated from these chickens. Furthermore, it replicated in lowand high-passage MDCC-MSB1 cells similarly to a low-passage CAV field isolate that contains a different VP 1 "hypervariable region." The regeneration of CAV from PCR products directly from naturally infected carcasses, as performed in this study, provides a tool for the evaluation of distinct genetic polymorphisms that may be detected in specimens where infective virions are no longer available. Our results also provide some insight into the differential susceptibility of cell lines for low-passage CAV field isolates.

Immunogenetics, Jul 7, 2018

The Figure 3 in the original version of this article was incorrectly published. In this article t... more The Figure 3 in the original version of this article was incorrectly published. In this article the top panel of Figure 3 that describes the amino acid sequence alignment is now presented correctly. The original article has been corrected.

Journal of Virology, May 1, 1995

With cDNA probes and by Northern (RNA) blot analysis, a region containing immediate-early (IE) ge... more With cDNA probes and by Northern (RNA) blot analysis, a region containing immediate-early (IE) genes in the channel catfish virus (CCV) genome was identified. IE transcription in CCV-infected cells appears to be restricted to the terminal repeat region, suggesting that CCV is most closely related to the alpha subfamily of herpesviruses. CCV DNA fragments from this region encoding IE transcripts were cloned. Northern analysis with one of these cloned fragments, a 3,927-bp EcoRI-XbaI fragment, indicates that it encodes two IE transcripts. Both transcripts (ie1 and ie2) were characterized by S1 nuclease analysis, primer extension analysis, and analysis of cDNAs. The ie2 transcript is a 1.3-kb bicistronic mRNA containing open reading frame (ORF) 8a and ORF 9. ORF 8a is a 5-truncated version of ORF 8 which, along with ORF 9, was previously identified (A. J. Davison, Virology 186:9-14, 1992). The ie1 transcript is 0.6 kb in size, contains only ORF 9, and is expressed at a level approximately six times that of ie2 in cycloheximide-treated cells. The putative product of ORF 9 is predicted to have a basic pI and contains a potential zinc-binding domain, making it a probable transcription factor. ORF 8a encodes a putative product which is very hydrophobic, an unusual characteristic for an IE protein.

Annals of the New York Academy of Sciences, Jun 1, 1985

Elucidation of the mechanism of RNA splicing, the excision of intervening sequences (IVSs) from h... more Elucidation of the mechanism of RNA splicing, the excision of intervening sequences (IVSs) from higher eukaryotic mRNA precursor molecules (pre-mRNA), remains one of the central problems in modem molecular biology. RNA splicing is a highly accurate process, with precise recognition of coding-intervening sequence boundaries. Over the past few years, it has become evident that a considerable fraction of thalassemias results from deficient globin mRNA due to aberrant pre-mRNA splicing (Spritz and Forget’ and Orkin and Kazazian’ for reviews). Aberrant RNA splicing probably underlies many other genetic diseases as well. Thus, understanding the RNA splicing process is of profound importance for both fundamental biology and medicine. The principal determinant of splicing accuracy is the nucleotide sequence of the pre-mRNA. Comparisons of large numbers of splice sites have demonstrated that almost all IVSs begin with the dinucleotide GU and end with the dinucleotide AG.)s4 Furthermore, the sequences immediately surrounding splice sites have considerable similarity, and so-called “consensus sequences” have been compiled for the 5’ (“donor”) and 3’ (“acceptor”) splice site region^.^.^ The donor splice consensus consists of the sequence C,AGgusgu. The acceptor splice consensus is less stringent, consisting of (:),x:agG (n 2 11). Thus, the acceptor splice consensus consists principally of the dinucleotide AG preceded by a relatively pyrimidine-rich region! Furthermore, the dinucleotide AG has never been observed between 5 and 15 bases 5’ to an acceptor splice site, and an AG occurs within 25 bases in the 5‘ direction of only 10% of acceptor splice sites: Mutations in these consensus regions have been associated with aberrant pre-mRNA splicing in several types of thalassemia? A ubiquitous small ribonucleoprotein complex in higher eukaryotic nuclei containing U 1 RNA7-9 has been shown to bind specifically to the donor splice consensus region of pre-mRNA in vitro.” The 5’ end of U1 RNA has sequence complementarity to the splice consensus regions and may be a component of the splice site recognition apparatus.’.”-” Little sequence homology is evident beyond the splice donor and splice acceptor consensus sequence regions of most I V S S ’ ~ . ’ ~ except in yeast, in which a third consensus sequence occurs

Avian Diseases, Dec 1, 2016

Corn stored outside could become contaminated with avian influenza virus (AIV) from wild bird dro... more Corn stored outside could become contaminated with avian influenza virus (AIV) from wild bird droppings. AIVcontaminated ingredients could pass into the poultry flocks in nonpelleted chicken feed. The efficacy of two disinfectants at inactivating AIV in chicken feed was evaluated. Both Termin-8 (a blend of formaldehyde, propionic acid, terpenes, and surfactant) and Finio (a blend of approved phytochemicals and carboxylic acids) effectively inactivated AIV in chicken feed. Because stability of infectious AIV in chicken feed is limited, we evaluated addition of protein (skim milk powder) to the virus suspension. Protein prolonged the stability of AIV in untreated feed to 24 hr at 24 C. However, both feed disinfectants were able to inactivate the virus in feed even when protected by skim milk powder. RESUMEN. Nota de investigación-Inactivación del virus de la influenza aviar en alimento de pollo no peletizado. El maíz almacenado en el exterior podría contaminarse con el virus de la influenza aviar (AIV) a partir de excremento de aves silvestres. Los ingredientes contaminados con el virus de influenza aviar podrían pasar a las parvadas avícolas comerciales a través de alimentos no peletizados. Se evaluó la eficacia de dos desinfectantes para inactivar al virus de influenza aviar en alimentos para pollos. Tanto Termin-8 (una mezcla de formaldehído, ácido propiónico, terpenos, y un agente surfactante) y Finio (una mezcla de fitoquímicos y ácidos carboxílicos aprobados) inactivaron de manera efectiva al virus de la influenza aviar en alimentos de pollo. Debido a que la estabilidad de los virus infecciosos de la influenza aviar en alimentos de pollo es limitada, se evaluó la adición de proteínas (leche descremada en polvo) a la suspensión de virus. La proteína prolonga la estabilidad del virus de la influenza aviar en el alimento sin tratar por 24 horas a 24 C. Sin embargo, los dos desinfectantes para alimentos fueron capaces de inactivar el virus en los alimentos, incluso cuando el virus estaba protegido por leche descremada en polvo. Key words: avian influenza virus, chicken feed, inactivation of avian influenza virus Abbreviations: AF ¼ allantoic fluid; AI ¼ avian influenza; AIV ¼ AI virus; ECE ¼ embryonated chicken egg; EID 50 ¼ 50% egg infectious dose; qRT-PCR ¼ quantitative reverse transcriptase polymerase chain reaction; SPF ¼ specific-pathogen-free

Virology Journal, Sep 21, 2010

Persistent infection of macrophages with bovine herpesvirus 4 (BoHV-4) has been proposed to play ... more Persistent infection of macrophages with bovine herpesvirus 4 (BoHV-4) has been proposed to play a secondary causal role, along with bacterial infection, in bovine post-partum metritis. Mechanisms of maintenance of BoHV-4 persistent infection are not understood. We previously generated in vitro models of BoHV-4 persistent infection in human rhadomyosarcoma and bovine macrophage cell lines by drug selection of cells infected with BoHV-4 carrying a drug-resistance marker, and demonstrated circular episomal BoHV-4 genomes. In the present study, we used fluorescent in situ hybridization (FISH) to demonstrate BoHV-4 genomes also integrated into the genomes of these persistently infected cells.

Aquaculture Research, Nov 1, 2009

Ichthyophthirius multi¢liis (Ich), a ciliated protozoan parasite of ¢sh, expresses surface antige... more Ichthyophthirius multi¢liis (Ich), a ciliated protozoan parasite of ¢sh, expresses surface antigens (i-antigens), which react with host antibodies that render them immobile. The nucleotide sequence of an i-antigen gene of I. multi¢liis strain ARS-6 was deduced. The predicted protein of 47493 Da is comprised of 460 amino acids (aa's) arranged into ¢ve imperfect repeats with periodic cysteine residues with the structure: CX (19)20 CX 2 CX 16 À 27 CX 2 CX 20(21) CX 3. The N-terminal aa's typify a signal peptide motif while a stretch of C-terminal aa's resemble a glycosylp hosphatidyl^inositol (GPI)-anchor addition site. The degree of deduced i-antigen aa sequence identity of strain ARS-6 (GenBank accession # ACH87654 and # ACH95659) with other I. multi¢liis i-antigen sequences present in GenBank ranges from 99% to 36% identity with 52 kDa i-antigens of I. multi¢liis strain G5 (accession #s AAK94941 and AAK01661 respectively). Immunoblot analysis of i-antigens following exposure of I. multi¢liis theronts to cat¢sh anti-I. multi¢liis immune serum did not show any appreciable alteration in i-antigen expression. The mechanism that regulates i-antigen expression in I. multi¢liis remains a puzzling question.

Springer eBooks, 1982

The objective of this introduction is to develop concisely the context in which biochemical studi... more The objective of this introduction is to develop concisely the context in which biochemical studies of Epstein—Barr virus (EBV) have been undertaken. Elements of history and biology are relevant to an understanding of the somewhat unusual course of biochemical research with EBV.

Avian Diseases, Sep 1, 2017

We previously demonstrated that chickens primed with a recombinant Newcastle disease virus LaSota... more We previously demonstrated that chickens primed with a recombinant Newcastle disease virus LaSota (rLS) expressing the S2 gene of infectious bronchitis virus (IBV) and boosted with an attenuated IBV Massachusetts (Mass)-type vaccine were protected against IBV Arkansas (Ark)-type virulent challenge. A possible basis for the reported ability of IBV 4/91 (serotype 793/B) vaccine to protect against divergent IBV strains (e.g., QX, Q1, and D1466) in a prime-boost approach with an IBV Mass vaccine is that an immune response against the S2 protein of IBV 4/91 is cross-protective. Therefore, we evaluated the protective capabilities of the S2 protein of IBV 4/91 expressed from rLS. The level of S2 amino acid sequence identity between 4/91 and the Ark challenge strain used in this study (90.7%) is within the range of S2 amino acid sequence identities between 4/91 and Q1 (91%-94%) and QX (89%-94%) strains. Chickens primed with attenuated Mass IBV at 1 day of age and boosted with rLS/ IBV.S2-4/91 at 14 days of age were challenged with a virulent Ark IBV strain at 28 days of age. Protection (reduction of clinical signs and viral loads) assessed 5 days postchallenge showed nonsignificant differences between chickens primed with Mass vaccine and boosted with rLS/IBV.S2-4/91 and chickens vaccinated with Mass only. Thus, the observed level of protection is attributable only to the effect of the Mass vaccine, indicating that the S2 of IBV 4/91 does not induce broad cross-protective immunity.

Avian Diseases, Dec 10, 2019

SUMMARY. A commercial Arkansas (Ark) Delmarva Poultry Industry (DPI)-type vaccine and a more homo... more SUMMARY. A commercial Arkansas (Ark) Delmarva Poultry Industry (DPI)-type vaccine and a more homogeneous population of that vaccine obtained previously through adaptation to chicken embryo kidney (CEK) cells (CEK-ArkDPI) were used as a model to further understand the impact of population genetic structure on generation of immune responses and protection. In a first experiment, vaccinated chickens were challenged with an IBV Ark99-type virulent strain (AL/4614/98). Despite extensive sequence similarity between the vaccines, the more heterogeneous commercial ArkDPI was more efficient at reducing viral loads in challenged chickens, while respiratory signs and tracheal lesions were reduced similarly by either vaccine. A distinct subpopulation of the Ark challenge virus showing asparagine at S1 position 56 was consistently negatively selected by immune pressure originating from vaccination with either vaccine. Antibody levels and antibody avidity to Ark-type S1 protein were greater in CEK-ArkDPI-vaccinated chickens compared to chickens vaccinated with the more diverse commercial ArkDPI vaccine. Synchronous replication of a homogeneous virus population likely elicits clonal expansion and affinity maturation of a greater number of responding B cells compared to a diverse virus population continuously changing its proportion of phenotypes during replication. The results of a second experiment showed that during initial vaccine virus replication (24 and 48 hr postvaccination), the virus population showing increased diversity (commercial ArkDPI) achieved higher concentrations of IBV RNA in the trachea compared to the more homogenous virus. mRNA expression of genes associated with innate immune responses in the trachea 48 hr postvaccination generally showed greater upregulation in chickens vaccinated with the heterogeneous commercial ArkDPI vaccine compared to the CEK-adapted virus. The greater upregulation of these genes is likely associated with higher virus replication achieved by the heterogeneous commercial vaccine. Thus, while the adaptive antibody response was favored by the more homogenous structure of the CEK-ArkDPI vaccine population (higher antibody levels and antibody avidity), the innate immune response was favored by the more diverse viral population of the commercial ArkDPI. We confirmed previous results that distinct subpopulations in wild Ark challenge virus become selected by immune pressure originating from vaccination, and we concluded that the population structure of IBV vaccines impacts innate immune response, antibody avidity, and protection.

Nucleic Acids Research, 1988

Proceedings of the National Academy of Sciences of the United States of America, Dec 1, 1987

We have isolated a Ul small nuclear RNA (snRNA) gene from common bean (Phaseolus vulgaris). The h... more We have isolated a Ul small nuclear RNA (snRNA) gene from common bean (Phaseolus vulgaris). The haploid bean genome contains only one or a few copies of the Ul snRNA gene. The bean and human Ul snRNA genes are 65% homologous but share no significant similarity in the 5' or 3' flanking regions. The predicted secondary structure of bean Ul snRNA is identical to that of other Ul snRNAs, and the

Journal of Applied Microbiology, Sep 1, 2005

To analyse interspecies and intraspecies differences based on the 16S-23S rRNA intergenic spacer ... more To analyse interspecies and intraspecies differences based on the 16S-23S rRNA intergenic spacer region (ISR) sequences of the fish pathogens Edwardsiella ictaluri and Edwardsiella tarda. Methods and Results: The 16S-23S rRNA spacer regions of 19 Edw. ictaluri and four Edw. tarda isolates from four geographical regions were amplified by PCR with primers complementary to conserved sequences within the flanking 16S-23S rRNA coding sequences. Two products were generated from all isolates, without interspecies or intraspecific size polymorphisms. Sequence analysis of the amplified fragments revealed a smaller ISR of 350 bp, which contained a gene for tRNA Glu , and a larger ISR of 441 bp, which contained genes for tRNA Ile and tRNA Ala. The sequences of the smaller ISR of different Edw. ictaluri isolates were essentially identical to each other. Partial sequences of larger ISR from several Edw. ictaluri isolates also revealed no differences from the one complete Edw. ictaluri large ISR sequence obtained. The sequences of the smaller ISR of Edw. tarda were 97% identical to the Edw. ictaluri smaller ISR and the larger ISR were 96-98% identical to the Edw. ictaluri larger ISR sequence. The Edw. tarda isolates displayed limited ISR sequence heterogeneity, with ‡97% sequence identity among isolates for both small and large ISR. Conclusions: There is a high degree of size and sequence similarity of 16S-23S ISR both among isolates within Edw. ictaluri and Edw. tarda species and between the two species. Significance and Impact of the Study: Our results confirm a close genetic relationship between Edw. ictaluri and Edw. tarda and the relative homogeneity of Edw. ictaluri isolates compared with Edw. tarda isolates. Because no differences were found in ISR sequences among Edw. ictaluri isolates, sequence analysis of the ISR will not be useful to distinguish isolates of Edw. ictaluri. However, we identified restriction sites that differ between ISR sequences of Edw. ictaluri and Edw. tarda, which will be useful in distinguishing the two species.

Journal of Clinical Microbiology, Jul 1, 2005

Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus with no clear disease association. Previous s... more Bovine herpesvirus 4 (BoHV-4) is a gammaherpesvirus with no clear disease association. Previous studies have demonstrated that macrophages can harbor persistent BoHV-4. We found that the addition of prostaglandin E2 (PGE2) to bovine macrophage cells persistently infected with BoHV-4 increases viral replication. Because opportunistic infection can increase PGE2 production, we propose a link between opportunistic infection, PGE2 production, and BoHV-4 replication.

Diseases of Aquatic Organisms, Mar 13, 2007

Conroy 1969). A. hydrophila infects many species of fish and other terrestrial animals (Colwell e... more Conroy 1969). A. hydrophila infects many species of fish and other terrestrial animals (Colwell et al. 1986), including humans (Janda & Duffey 1988). Particular importance is attached to A. hydrophila from a public health perspective due to its involvement in foodborne gastroenteritis and various opportunistic infections in immunocompromised human patients (Alt