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Byung-whi Kong - One of the best experts on this subject based on the ideXlab platform.
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Genome sequence comparison of two United States live attenuated vaccines of infectious laryngotracheitis virus (ILTV)
Virus Genes, 2012Co-Authors: Yohanna Gita Chandra, Byung-whi KongAbstract:This study was conducted to identify unique nucleotide differences in two U.S. chicken embryo origin (CEO) vaccines [LT Blen (GenBank accession: JQ083493) designated as vaccine 1; Laryngo-Vac^® (GenBank accession: JQ083494) designated as vaccine 2] of infectious laryngotracheitis virus (ILTV) genomes compared to an Australian Serva vaccine reference ILTV genome sequence [ Gallid Herpesvirus 1 (GaHV - 1) ; GenBank accession number: HQ630064]. Genomes of the two vaccine ILTV strains were sequenced using Illumina Genome Analyzer 2X of 36 cycles of single-end reads. Results revealed that few nucleotide differences (23 in vaccine 1; 31 in vaccine 2) were found and indicate that the US CEO strains are practically identical to the Australian Serva CEO strain, which is a European-origin vaccine. The sequence differences demonstrated the spectrum of variability among vaccine strains. Only eight amino acid differences were found in ILTV proteins including UL54, UL27, UL28, UL20, UL1, ICP4, and US8 in vaccine 1. Similarly, in vaccine 2, eight amino acid differences were found in UL54, UL27, UL28, UL36, UL1, ICP4, US10, and US8. Further comparison of US CEO vaccines to several ILTV genome sequences revealed that US CEO vaccines are genetically close to both the Serva vaccine and 63140/C/08/BR (GenBank accession: HM188407) and are distinct from the two Australian-origin CEO vaccines, SA2 (GenBank accession: JN596962) and A20 (GenBank accession: JN596963), which showed close similarity to each other. These data demonstrate the potential of high-throughput sequencing technology to yield insight into the sequence variation of different ILTV strains. This information can be used to discriminate between vaccine ILTV strains and further, to identify newly emerging mutant strains of field isolates.
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Genome-wide host responses against infectious laryngotracheitis virus vaccine infection in chicken embryo lung cells
BMC Genomics, 2012Co-Authors: Walter Bottje, Byung-whi KongAbstract:Background Infectious laryngotracheitis virus (ILTV; Gallid Herpesvirus 1) infection causes high mortality and huge economic losses in the poultry industry. To protect chickens against ILTV infection, chicken-embryo origin (CEO) and tissue-culture origin (TCO) vaccines have been used. However, the transmission of vaccine ILTV from vaccinated- to unvaccinated chickens can cause severe respiratory disease. Previously, host cell responses against virulent ILTV infections were determined by microarray analysis. In this study, a microarray analysis was performed to understand host-vaccine ILTV interactions at the host gene transcription level.
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Genome-wide host responses against infectious laryngotracheitis virus vaccine infection in chicken embryo lung cells
BMC Genomics, 2012Co-Authors: Walter Bottje, Byung-whi KongAbstract:Background Infectious laryngotracheitis virus (ILTV; Gallid Herpesvirus 1) infection causes high mortality and huge economic losses in the poultry industry. To protect chickens against ILTV infection, chicken-embryo origin (CEO) and tissue-culture origin (TCO) vaccines have been used. However, the transmission of vaccine ILTV from vaccinated- to unvaccinated chickens can cause severe respiratory disease. Previously, host cell responses against virulent ILTV infections were determined by microarray analysis. In this study, a microarray analysis was performed to understand host-vaccine ILTV interactions at the host gene transcription level. Results The 44 K chicken oligo microarrays were used, and the results were compared to those found in virulent ILTV infection. Total RNAs extracted from vaccine ILTV infected chicken embryo lung cells at 1, 2, 3 and 4 days post infection (dpi), compared to 0 dpi, were subjected to microarray assay using the two color hybridization method. Data analysis using JMP Genomics 5.0 and the Ingenuity Pathway Analysis (IPA) program showed that 213 differentially expressed genes could be grouped into a number of functional categories including tissue development, cellular growth and proliferation, cellular movement, and inflammatory responses. Moreover, 10 possible gene networks were created by the IPA program to show intermolecular connections. Interestingly, of 213 differentially expressed genes, BMP2, C8orf79, F10, and NPY were expressed distinctly in vaccine ILTV infection when compared to virulent ILTV infection. Conclusions Comprehensive knowledge of gene expression and biological functionalities of host factors during vaccine ILTV infection can provide insight into host cellular defense mechanisms compared to those of virulent ILTV.
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Transcriptional profiling of host gene expression in chicken embryo lung cells infected with laryngotracheitis virus
BMC Genomics, 2010Co-Authors: Joon Jin Song, Walter Bottje, Ann Wooming, Xianyao Li, Huaijun Zhou, Byung-whi KongAbstract:Background Infection by infectious laryngotracheitis virus (ILTV; Gallid Herpesvirus 1 ) causes acute respiratory diseases in chickens often with high mortality. To better understand host-ILTV interactions at the host transcriptional level, a microarray analysis was performed using 4 × 44 K Agilent chicken custom oligo microarrays. Results Microarrays were hybridized using the two color hybridization method with total RNA extracted from ILTV infected chicken embryo lung cells at 0, 1, 3, 5, and 7 days post infection (dpi). Results showed that 789 genes were differentially expressed in response to ILTV infection that include genes involved in the immune system (cytokines, chemokines, MHC, and NF-κB), cell cycle regulation (cyclin B2, CDK1, and CKI3), matrix metalloproteinases (MMPs) and cellular metabolism. Differential expression for 20 out of 789 genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of 789 differentially expressed genes revealed that 21 possible gene networks with intermolecular connections among 275 functionally identified genes. These 275 genes were classified into a number of functional groups that included cancer, genetic disorder, cellular growth and proliferation, and cell death. Conclusion The results of this study provide comprehensive knowledge on global gene expression, and biological functionalities of differentially expressed genes in chicken embryo lung cells in response to ILTV infections.
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Transcriptional profiling of host gene expression in chicken embryo lung cells infected with laryngotracheitis virus
BMC Genomics, 2010Co-Authors: Joon Jin Song, Walter Bottje, Ann Wooming, Xianyao Li, Huaijun Zhou, Byung-whi KongAbstract:Infection by infectious laryngotracheitis virus (ILTV; Gallid Herpesvirus 1) causes acute respiratory diseases in chickens often with high mortality. To better understand host-ILTV interactions at the host transcriptional level, a microarray analysis was performed using 4 × 44 K Agilent chicken custom oligo microarrays. Microarrays were hybridized using the two color hybridization method with total RNA extracted from ILTV infected chicken embryo lung cells at 0, 1, 3, 5, and 7 days post infection (dpi). Results showed that 789 genes were differentially expressed in response to ILTV infection that include genes involved in the immune system (cytokines, chemokines, MHC, and NF-κB), cell cycle regulation (cyclin B2, CDK1, and CKI3), matrix metalloproteinases (MMPs) and cellular metabolism. Differential expression for 20 out of 789 genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of 789 differentially expressed genes revealed that 21 possible gene networks with intermolecular connections among 275 functionally identified genes. These 275 genes were classified into a number of functional groups that included cancer, genetic disorder, cellular growth and proliferation, and cell death. The results of this study provide comprehensive knowledge on global gene expression, and biological functionalities of differentially expressed genes in chicken embryo lung cells in response to ILTV infections.
Scott G. Tyack - One of the best experts on this subject based on the ideXlab platform.
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Sequence characteristics of a gene in infectious laryngotracheitis virus homologous to glycoprotein D of herpes simplex virus
Dna Sequence, 2009Co-Authors: Michael A Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwant, Michael SheppardAbstract:An infectious laryngotracheitis virus (ILTV, Gallid Herpesvirus 1) gene homologous to glycoprotein D of herpes simplex virus (HSV) was identified and characterized by its nucleotide and derived amino acid sequence. The ILTV gD gene is located in the unique short region (Us) and contains an open reading frame capable of specifying a polypeptide of 380 amino acids, including N-and C-terminal hydrophobic domains consistent with signal and anchor regions respectively, and no potential sites for N-glycosylation. Alignment of the amino acid sequence with those published for HSV gD, equine Herpesvirus type 1 (EHV-1) gD, pseudorabies virus (PRV) gp50, Marek's disease virus (MDV) gD, Herpesvirus of turkeys (HVT) gD and bovine Herpesvirus type 1 (BHV-1) gD showed similarities over the N-terminal region, with the greatest differences occurring in the C-terminal. The identical positioning of 6 cysteine residues supports the hypothesis of common ancestry of Herpesvirus family (McGeoch, 1990) and is consistent with the...
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Nucleotide sequence of the left-terminus of infectious laryngotracheitis virus (Gallid Herpesvirus 1) SA-2 strain
Archives of Virology, 1997Co-Authors: M. A. Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwan, M. SheppardAbstract:The nucleotide sequence of 10.6 kilobase pairs (kbp) at the left-terminus of infectious laryngotracheitis virus (ILTV) SA-2 vaccine strain was determined. Several features were elucidated, including, 102 base pair (bp) inverted repeats separated by 750 bp of unique sequence which contains an NF-1 binding site indicating that the terminal may be a site for an origin of replication. Other direct repeats were also found in this region. To the right of the inverted repeat region, a 2130 bp region was found to contain small open reading frames (ORFs) of less than 100 aa. Another potential ORF was found to the right of the region containing the small ORFs which consisted of two 184 bp direct repeats inserted into the reading frame, which would truncate the putative product. Only one copy of this repeat was found in the corresponding homologue of the wild type strain SA-0. Six other ORFs were found, which shared little or no identity to homologues of other alphaHerpesviruses, suggesting that these putative genes are unique to ILTV.
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Comparison of the Genomic Short Regions of a Vaccine Strain (SA-2) and a Virulent Strain (CSW-1) of Infectious Laryngotracheitis Virus (Gallid Herpesvirus 1)
Avian Diseases, 1996Co-Authors: Halina Trist, Scott G. Tyack, C. T. Prideaux, Michael A Johnson, Michael SheppardAbstract:SUMMARY. Restriction enzyme linkage maps were produced for the genomic short region of the virulent infectious laryngotracheitis virus (CSW-1 strain). After comparison with the equivalent restriction enzyme linkage maps for the infectious laryngotracheitis virus SA-2 strain (a vaccine strain), it was determined that the maps for the short regions of the two strains were identical, apart from a single section in each of the inverted terminal repeats. Each inverted terminal repeat of the SA-2 strain was discovered to contain 467 base pairs more DNA than the CSW-1 strain's inverted terminal repeats. This extra DNA was more precisely mapped entirely within the EcoRI fragments D and d of SA-2, which were found to form part of the SmaI fragments U and P of SA-2 and Q and b of SA-2 and to contain one SmaI restriction enzyme site.
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molecular evolution of infectious laryngotracheitis virus iltv Gallid Herpesvirus 1 an ancient example of the alphaherpesviridae
Veterinary Microbiology, 1995Co-Authors: Michael A Johnson, Scott G. TyackAbstract:An analysis of two essential genes of infectious laryngotracheitis virus (ILTV), glycoprotein D (gD) and the immediate early gene, herpes simplex virus homologue ICP27, was performed with the equivalent gene homologues from several alphaHerpesviruses. Amino acid (aa) sequence analysis revealed that these ILTV genes shared limited homology to other alphaHerpesvirus equivalents and were distinct from the two other avian Herpesviruses, Marek's disease virus (MDV) and Herpesvirus of turkeys (HVT). Simplex and varicella group viruses are clearly separate from the avian group. The amino acid sequences of these ILTV genes will be presented with comparisions to the homologues from other alphaHerpesviruses, contributing further evidence of the evolution of this group of viruses from a common progenitor and that ILTV could be an ancient example of the Alphaherpesvirinae.
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ICP27 immediate early gene, glycoprotein K (gK) and DNA helicase homologues of infectious laryngotracheitis virus (Gallid Herpesvirus 1) SA-2 strain
Archives of Virology, 1995Co-Authors: M. A. Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwan, M. SheppardAbstract:A 4.8 kilobase segment located at the left-terminal in the unique long (U_L) region of infectious laryngotracheitis virus (ILTV) SA-2 strain contained three open reading frames (ORFs). The first of 421 amino acids (aa) was located at map units 0.065 to 0.07, and its predicted 48 kiloDaltons (kDa) protein product has significant homology to the immediate early regulatory protein ICP27 (UL54) of herpes simplex virus type-1 (HSV-1), to varicella-zoster virus (VZV) ORF4 and to equine Herpesvirus 1 (EHV-1) ORF5. The zinc finger conserved in the C-terminal of the proteins from HSV-1, VZV and EHV-1, is poorly conserved in ILTV homologue. The second ORF of 336 aa, located at map units 0.075 to 0.08, has a predicted molecular weight (MW) of 38 kDa with significant homology to glycoprotein K (gK) of HSV-1 (UL53), ORF5 of VZV and ORF6 of EHV-1. ILTV gK has features characteristic of a membrane-bound glycoprotein. The 3′ region of a third ORF was located at map units 0.08 to 0.095. Translation of the sequence revealed significant homology to the 3′-region of the DNA helicase-primase complex protein (UL52) of HSV-1, ORF6 of VZV and ORF 7 of EHV-1. Northern blot analyses were used to characterize the ILTV ICP27, gK and DNA helicase mRNAs. The data revealed that ILTV ICP27 is an immediate early gene that encodes a 1.6 kb mRNA, ILTV gK encodes a late transcript of 1.8 kb, while ILTV DNA helicase encodes a late transcript of 3.7 kb.
M. Sheppard - One of the best experts on this subject based on the ideXlab platform.
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Nucleotide sequence of the left-terminus of infectious laryngotracheitis virus (Gallid Herpesvirus 1) SA-2 strain
Archives of Virology, 1997Co-Authors: M. A. Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwan, M. SheppardAbstract:The nucleotide sequence of 10.6 kilobase pairs (kbp) at the left-terminus of infectious laryngotracheitis virus (ILTV) SA-2 vaccine strain was determined. Several features were elucidated, including, 102 base pair (bp) inverted repeats separated by 750 bp of unique sequence which contains an NF-1 binding site indicating that the terminal may be a site for an origin of replication. Other direct repeats were also found in this region. To the right of the inverted repeat region, a 2130 bp region was found to contain small open reading frames (ORFs) of less than 100 aa. Another potential ORF was found to the right of the region containing the small ORFs which consisted of two 184 bp direct repeats inserted into the reading frame, which would truncate the putative product. Only one copy of this repeat was found in the corresponding homologue of the wild type strain SA-0. Six other ORFs were found, which shared little or no identity to homologues of other alphaHerpesviruses, suggesting that these putative genes are unique to ILTV.
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ICP27 immediate early gene, glycoprotein K (gK) and DNA helicase homologues of infectious laryngotracheitis virus (Gallid Herpesvirus 1) SA-2 strain
Archives of Virology, 1995Co-Authors: M. A. Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwan, M. SheppardAbstract:A 4.8 kilobase segment located at the left-terminal in the unique long (U_L) region of infectious laryngotracheitis virus (ILTV) SA-2 strain contained three open reading frames (ORFs). The first of 421 amino acids (aa) was located at map units 0.065 to 0.07, and its predicted 48 kiloDaltons (kDa) protein product has significant homology to the immediate early regulatory protein ICP27 (UL54) of herpes simplex virus type-1 (HSV-1), to varicella-zoster virus (VZV) ORF4 and to equine Herpesvirus 1 (EHV-1) ORF5. The zinc finger conserved in the C-terminal of the proteins from HSV-1, VZV and EHV-1, is poorly conserved in ILTV homologue. The second ORF of 336 aa, located at map units 0.075 to 0.08, has a predicted molecular weight (MW) of 38 kDa with significant homology to glycoprotein K (gK) of HSV-1 (UL53), ORF5 of VZV and ORF6 of EHV-1. ILTV gK has features characteristic of a membrane-bound glycoprotein. The 3′ region of a third ORF was located at map units 0.08 to 0.095. Translation of the sequence revealed significant homology to the 3′-region of the DNA helicase-primase complex protein (UL52) of HSV-1, ORF6 of VZV and ORF 7 of EHV-1. Northern blot analyses were used to characterize the ILTV ICP27, gK and DNA helicase mRNAs. The data revealed that ILTV ICP27 is an immediate early gene that encodes a 1.6 kb mRNA, ILTV gK encodes a late transcript of 1.8 kb, while ILTV DNA helicase encodes a late transcript of 3.7 kb.
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Gallid Herpesvirus 1 (infectious laryngotracheitis virus): cloning and physical maps of the SA-2 strain
Archives of Virology, 1991Co-Authors: M. A. Johnson, C. T. Prideaux, K. Kongsuwan, M. Sheppard, K. J. FaheyAbstract:Clones representing 90% of the genome of Gallid Herpesvirus 1 (infectious laryngotracheitis virus; ILTV) were obtained and used in hybridization experiments to construct Eco RI, Kpn I amd Sma I physical maps. The genome was 155 kilobase pairs (kbp) and comprised of a long unique sequence (120 kbp) and a short unique sequence (17 kbp) bounded by repeat sequences each of 9 kbp. An unrelated second pair of repeat sequences was located at 0.67 and 0.88 map untis. A terminal repeat of the unique long region (U_L) was also detected, but no isomerization of U_L was detected.
C. T. Prideaux - One of the best experts on this subject based on the ideXlab platform.
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Sequence characteristics of a gene in infectious laryngotracheitis virus homologous to glycoprotein D of herpes simplex virus
Dna Sequence, 2009Co-Authors: Michael A Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwant, Michael SheppardAbstract:An infectious laryngotracheitis virus (ILTV, Gallid Herpesvirus 1) gene homologous to glycoprotein D of herpes simplex virus (HSV) was identified and characterized by its nucleotide and derived amino acid sequence. The ILTV gD gene is located in the unique short region (Us) and contains an open reading frame capable of specifying a polypeptide of 380 amino acids, including N-and C-terminal hydrophobic domains consistent with signal and anchor regions respectively, and no potential sites for N-glycosylation. Alignment of the amino acid sequence with those published for HSV gD, equine Herpesvirus type 1 (EHV-1) gD, pseudorabies virus (PRV) gp50, Marek's disease virus (MDV) gD, Herpesvirus of turkeys (HVT) gD and bovine Herpesvirus type 1 (BHV-1) gD showed similarities over the N-terminal region, with the greatest differences occurring in the C-terminal. The identical positioning of 6 cysteine residues supports the hypothesis of common ancestry of Herpesvirus family (McGeoch, 1990) and is consistent with the...
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Nucleotide sequence of the left-terminus of infectious laryngotracheitis virus (Gallid Herpesvirus 1) SA-2 strain
Archives of Virology, 1997Co-Authors: M. A. Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwan, M. SheppardAbstract:The nucleotide sequence of 10.6 kilobase pairs (kbp) at the left-terminus of infectious laryngotracheitis virus (ILTV) SA-2 vaccine strain was determined. Several features were elucidated, including, 102 base pair (bp) inverted repeats separated by 750 bp of unique sequence which contains an NF-1 binding site indicating that the terminal may be a site for an origin of replication. Other direct repeats were also found in this region. To the right of the inverted repeat region, a 2130 bp region was found to contain small open reading frames (ORFs) of less than 100 aa. Another potential ORF was found to the right of the region containing the small ORFs which consisted of two 184 bp direct repeats inserted into the reading frame, which would truncate the putative product. Only one copy of this repeat was found in the corresponding homologue of the wild type strain SA-0. Six other ORFs were found, which shared little or no identity to homologues of other alphaHerpesviruses, suggesting that these putative genes are unique to ILTV.
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Comparison of the Genomic Short Regions of a Vaccine Strain (SA-2) and a Virulent Strain (CSW-1) of Infectious Laryngotracheitis Virus (Gallid Herpesvirus 1)
Avian Diseases, 1996Co-Authors: Halina Trist, Scott G. Tyack, C. T. Prideaux, Michael A Johnson, Michael SheppardAbstract:SUMMARY. Restriction enzyme linkage maps were produced for the genomic short region of the virulent infectious laryngotracheitis virus (CSW-1 strain). After comparison with the equivalent restriction enzyme linkage maps for the infectious laryngotracheitis virus SA-2 strain (a vaccine strain), it was determined that the maps for the short regions of the two strains were identical, apart from a single section in each of the inverted terminal repeats. Each inverted terminal repeat of the SA-2 strain was discovered to contain 467 base pairs more DNA than the CSW-1 strain's inverted terminal repeats. This extra DNA was more precisely mapped entirely within the EcoRI fragments D and d of SA-2, which were found to form part of the SmaI fragments U and P of SA-2 and Q and b of SA-2 and to contain one SmaI restriction enzyme site.
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ICP27 immediate early gene, glycoprotein K (gK) and DNA helicase homologues of infectious laryngotracheitis virus (Gallid Herpesvirus 1) SA-2 strain
Archives of Virology, 1995Co-Authors: M. A. Johnson, Scott G. Tyack, C. T. Prideaux, K. Kongsuwan, M. SheppardAbstract:A 4.8 kilobase segment located at the left-terminal in the unique long (U_L) region of infectious laryngotracheitis virus (ILTV) SA-2 strain contained three open reading frames (ORFs). The first of 421 amino acids (aa) was located at map units 0.065 to 0.07, and its predicted 48 kiloDaltons (kDa) protein product has significant homology to the immediate early regulatory protein ICP27 (UL54) of herpes simplex virus type-1 (HSV-1), to varicella-zoster virus (VZV) ORF4 and to equine Herpesvirus 1 (EHV-1) ORF5. The zinc finger conserved in the C-terminal of the proteins from HSV-1, VZV and EHV-1, is poorly conserved in ILTV homologue. The second ORF of 336 aa, located at map units 0.075 to 0.08, has a predicted molecular weight (MW) of 38 kDa with significant homology to glycoprotein K (gK) of HSV-1 (UL53), ORF5 of VZV and ORF6 of EHV-1. ILTV gK has features characteristic of a membrane-bound glycoprotein. The 3′ region of a third ORF was located at map units 0.08 to 0.095. Translation of the sequence revealed significant homology to the 3′-region of the DNA helicase-primase complex protein (UL52) of HSV-1, ORF6 of VZV and ORF 7 of EHV-1. Northern blot analyses were used to characterize the ILTV ICP27, gK and DNA helicase mRNAs. The data revealed that ILTV ICP27 is an immediate early gene that encodes a 1.6 kb mRNA, ILTV gK encodes a late transcript of 1.8 kb, while ILTV DNA helicase encodes a late transcript of 3.7 kb.
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nucleotide sequence of infectious laryngotracheitis virus Gallid Herpesvirus 1 icp4 gene
Virus Research, 1995Co-Authors: Michael A Johnson, Scott G. Tyack, C. T. Prideaux, Kritaya Kongsuwan, Michael SheppardAbstract:Abstract The infectious laryngotracheitis virus (ILTV) gene encoding a homologue to the ICP4 protein of herpes simplex virus (HSV) has been mapped to the inverted repeat region. The complete nucleotide sequence of ILTV ICP4 has been determined. The ILTV ORF encoding ICP4 is 4386 nucleotides long, calculated from the first of four ATG codons, and has an overall G + C content of 59%. The ILTV ICP4 contains two domains of high homology which have been reported in other studies to be conserved in the ICP4 homologues of alphaHerpesviruses, and to be functionally important. Several regulatory features were identified including a serine-rich domain in region one. A more extensive serine-rich domain was located in region five which is also found in varicella-zoster virus (VZV) and bovine Herpesvirus 1. A 5.4 kb immediate early transcript was identified in infected primary kidney cells.
Roselene Ecco - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of the transcriptional status of host cytokines and viral genes in the trachea of vaccinated and non-vaccinated chickens after challenge with the infectious laryngotracheitis virus
Avian Pathology, 2016Co-Authors: Ariel Vagnozzi, Roselene Ecco, Sylva M. Riblet, Guillermo Zavala, Claudio L. Afonso, Maricarmen GarcíaAbstract:ABSTRACTInfectious laryngotracheitis is a highly contagious disease of chickens responsible for significant economic losses for the poultry industry worldwide. The disease is caused by Gallid Herpesvirus-1 (GaHV-1) commonly known as the infectious laryngotracheitis virus. Although characterized by their potential to regain virulence, chicken embryo origin (CEO) vaccines are the most effective vaccines against laryngotracheitis as they significantly reduce the replication of challenge virus in the trachea and conjunctiva. Knowledge on the nature of protective immunity elicited by CEO vaccines is very limited. Therefore, elucidating the origin of the immune responses elicited by CEO vaccination is relevant for development of safer control strategies. In this study the transcription levels of key host immune genes (IFN-γ, IFN-β, IL-1β, IL-6, IL-8, IL-18) and viral genes (ICP4, ICP27, UL46, UL49), as well as viral genome loads in trachea were quantified at 6 and 12 hours post-challenge of CEO vaccinated and n...
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Molecular characterization of infectious laryngotracheitis virus in naturally infected egg layer chickens in a multi-age flock in Brazil
Archives of Virology, 2015Co-Authors: Rodrigo De Macedo Couto, Ingred S. Preis, Juliana Fortes Vilarinho Braga, Bruno S. A. F. Brasil, Marcela Gonçalves Drummond, Nelson Rodrigo Da Silva Martins, Roselene EccoAbstract:The virus responsible for an outbreak of infectious laryngotracheitis (ILT) in a multi-age flock of egg layer chickens under quarantine in Brazil was characterized. Layer chickens from this area with circulating Gallid Herpesvirus 1 (GaHV 1) were evaluated using histopathology and molecular characterization techniques based on sequences of infected-cell polypeptide 4 (ICP4) and thymidine kinase (TK) genes. The infected chickens that were analyzed were PCR-positive for GaHV-1 in the trachea and negative in most trigeminal ganglia. The lack of ILT lesions in the conjunctiva and respiratory tissues, combined with detection of viral DNA in the trachea, was found to be associated with latent infection. The sequences from five farms obtained in the present study were identical, and there were no deletions within the 272- to 283-bp region of the ICP4 gene, as observed in the sequences of vaccine strains (CEO and TCO). The lack of a deletion in the ICP4 fragment analyzed in this study indicates that the chickens were infected with a field virus. The absence of the T252M mutation in a fragment of the TK gene, in addition to the low mortality rate observed, suggests that the outbreak in the state of Minas Gerais was not caused by a highly virulent strain but rather by a field virus of lower virulence. In addition, using phylogenetic reconstructions, it was found that this field strain was grouped together in a separate branch, apart from the previously characterized Brazilian strains. The introduction of vectored vaccines apparently has been effective in reducing clinical disease and lesions, and preventing new outbreaks of disease.
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Pathological, immunohistochemical, and molecular findings in commercial laying hens and in backyard chickens naturally infected with the infectious laryngotracheitis virus
Brazilian Journal of Poultry Science, 2014Co-Authors: Ingred S. Preis, Rodrigo M. Couto, Atl Fiúza, Camila Costa Silva, Jfv Braga, N. R. Da Silva Martins, Roselene EccoAbstract:Seventy-eight chickens from a very high poultry density (approximately eight million) region and twelve backyard chickens from neighboring areas were analyzed by histopathology and additional techniques for the presence of the infectious laryngotracheitis virus. The virus distribution was determined in different tissues using immunohistochemistry (IHC) and polymerase chain reaction (PCR). The disease was histopathologically diagnosed in 41.0% (32/78) of the commercial layers. Lesions were mainly characterized by syncytial cells with eosinophilic intranuclear inclusion body formed from the hyperplastic epithelium of the upper respiratory tract, primary and secondary bronchi, and conjunctiva. IHC showed 70% (21/30) positive signal in the larynx/trachea and, 53.8% (14/26) in the lungs, either in epithelial cells or syncytia. In the turbinates and paranasal sinuses, 29.6% (8/27) of samples showed positive signal. PCR detected the following Gallid Herpesvirus 1-positive percentages: conjunctiva 63.2% (31/49), lungs 57.6% (30/52), turbinates and paranasal sinuses 56% (28/50), and larynx/trachea 50% (39/78). IHC showed to be a useful additional tool for definitive ILT diagnosis, especially during the subacute phase of the disease when syncytial cells with intranuclear inclusion bodies are no longer observed. PCR using specific primers from ICP4 gene, generating a product of 237 base pairs, was sensitive for ILT diagnosis, and very useful for rapid detection of GaHV-1 in chickens. Fixed tissues allowing histopatological examination and detection of GaHV-1 by PCR, are a good option in areas where farms are located several hundred kilometers away from a diagnostic center, reducing problems with conservation of fresh samples and the risk of virus spread.
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Outbreak of infectious laryngotracheitis in large multi-age egg layer chicken flocks in Minas Gerais, Brazil
Pesquisa Veterinaria Brasileira, 2013Co-Authors: Ingred S. Preis, Juliana Fortes Vilarinho Braga, Rodrigo M. Couto, Bruno S. A. F. Brasil, Nelson Rodrigo Da Silva Martins, Roselene EccoAbstract:A recent (November 2010) outbreak of infectious laryngotracheitis (ILT) in a multi-age laying hen facility in Minas Gerais state, Brazil, is described. Previous ILT outbreak in laying hens was only notified in Sao Paulo state, Brazil, in 2002. In the outbreak described here, the affected population was approximately eight million hens, with flock sizes ranging from 100,000 to 2,900,000 chickens. The average mortality ranged from 1 to 6%, and morbidity was around 90% (most of the twenty seven farms of the area were positive for ILT virus). Three multi-age laying farms from one company were selected for this report. Clinical signs included prostration, dyspnea, conjunctivitis, occasional swelling of the paranasal sinuses and bloody mucous nasal discharge. Severely affected chickens presented with dyspnea, gasping and became cyanotic before death. At necropsy, these chickens had fibrinous exudate blocking the larynx and the lumen of cranial part of the trachea. In addition, conjunctivitis with intense hyperemia, edema and sinuses with caseous exudate were present. On histopathology, there were marked necrosis and desquamation of respiratory ephitelium and conjunctiva with numerous syncytial cells formation and fibrinous exudate. Moderate to marked non suppurative (especially lymphocytes and plasma cells) infiltration in the lamina propria also was observed. Sixteen out of 20 examined chickens, eosinophilic intranuclear inclusion bodies were observed in the syncytial cells. The DNA extracted from larynx and trachea produced positive PCR results for ILT virus (ILTV) DNA using formalin-fixed, paraffin embedded (FFPE) samples. Amplicons from a small region of ICP4 gene were submitted to sequencing and showed 100% identity with ILTV EU104910.1 (USA strain), 99% with ILTV JN596963.1 (Australian strain) and 91% with ILTV JN580316.1 (Gallid Herpesvirus 1 CEO vaccine strain) and JN580315.1 (Gallid Herpesvirus 1 TCO vaccine strain).
