| structure, stability and function of rna pseudoknots involved in stimulating ribosomal frameshifting. | programmed -1 ribosomal frameshifting has become the subject of increasing interest over the last several years, due in part to the ubiquitous nature of this translational recoding mechanism in pathogenic animal and plant viruses. all cis-acting frameshift signals encoded in mrnas are minimally composed of two functional elements: a heptanucleotide "slippery sequence" conforming to the general form x xxy yyz, followed by an rna structural element, usually an h-type rna pseudoknot, positioned an ... | 2000 | 10764589 |
| the amino and carboxyl domains of the infectious bronchitis virus nucleocapsid protein interact with 3' genomic rna. | previous studies indicated that the nucleocapsid (n) protein of infectious bronchitis virus (ibv) interacted with specific sequences in the 3' non-coding region of ibv rna. in order to identify domains in the n protein that bind to rna, the whole protein (409 amino acids) and six overlapping fragments were expressed as fusion polypeptides with six histidine-tags. using gel shift assays, the intact n protein and amino polypeptides, from residues 1 to 171 and residues 1 to 274, and carboxyl polype ... | 2000 | 10773316 |
| kinetics of lymphocytic subsets in chicken tracheal lesions infected with infectious bronchitis virus. | the kinetics of t-cells (cd3 positive (+), cd4+ and cd8+ cells) and b-cells (igg+, igm+ and iga+ cells) in chicken trachea were studied immunohistochemically and histopathologically following an intratracheal inoculation of infectious bronchitis virus (ibv). viral antigen was detected in the cytoplasm of tracheal epithelium from 16 hr to 6 days post-inoculation (p.i.) with a peak on 4 days p.i. a few igg+, igm+ and iga+ cells were detected in the submucosa from 8 hr p.i. thereafter igg+ and igm+ ... | 2000 | 10823726 |
| expression of reporter genes from the defective rna cd-61 of the coronavirus infectious bronchitis virus. | the defective rna (d-rna) cd-61, derived from the beaudette strain of the avian coronavirus infectious bronchitis virus (ibv), was used as an rna vector for the expression of two reporter genes, luciferase and chloramphenicol acetyltransferase (cat). d-rnas expressing the cat gene were demonstrated to be capable of producing cat protein in a helper-dependent expression system to about 1.6 microgram per 10(6) cells. the reporter genes were expressed from two different sites within the cd-61 seque ... | 2000 | 10859373 |
| localization of linear b-cell epitopes on infectious bronchitis virus nucleocapsid protein. | the nucleocapsid (n) protein of many viruses is highly conserved, immunogenic, and abundantly expressed during infection. these features make it a suitable candidate for diagnostic applications. the nucleocapsid protein of infectious bronchitis virus (ibv) was dissected into 12 fragments and expressed in escherichia coli. sera against australia t, china ch5, singapore p4, usa m41 and china t3 isolates were used to study the conservation and localization of the antigenic region on the ibv nucleoc ... | 2000 | 10865148 |
| further characterization of the coronavirus infectious bronchitis virus 3c-like proteinase and determination of a new cleavage site. | coronavirus infectious bronchitis virus (ibv) encodes a trypsin-like proteinase (3c-like proteinase) by orf 1a, which has been demonstrated to play a pivotal role in proteolytic processing of gene 1-encoded polyproteins. in our previous studies, the proteinase was identified as a 33-kda protein in ibv-infected cells, and its catalytic center was shown to consist of h(2820) and c(2922) residues. it is released from the 1a and 1a/1b polyproteins by autoprocessing at two q-s dipeptide bonds (q(2779 ... | 2000 | 10873746 |
| identification of avian infectious bronchitis virus by direct automated cycle sequencing of the s-1 gene. | direct automated cycle sequencing (dacs) of a reverse transcription-polymerase chain reaction (rt-pcr) product of the s-1 subunit of the spike peplomer gene was used to identify infectious bronchitis virus (ibv) serotypes. degenerate primers ck4 and ck2, utilized previously in our laboratory, were selected for dacs because they successfully amplify a wide range of serotypes represented by various reference strains and field isolates and the resulting polymerase chain reaction (pcr) product conta ... | 2000 | 10879913 |
| increased tracheal colonization in chickens without impairing pathogenic properties of avian pathogenic escherichia coli mt78 with a fimh deletion. | several studies suggest that the expression of f1 fimbriae could be involved in the virulence of escherichia coli for chickens. f1 fimbriae display multivalent properties such as adhesion to epithelia or interaction with the immune system that imply specific interactions between the adhesin fimh and different cell receptors. we constructed a delta fimh mutant of the avian pathogenic e. coli mt78 and evaluated its in vivo colonization and pathogenicity, as compared to that of the parent strain. t ... | 2000 | 10879915 |
| avian infectious bronchitis virus. | infectious bronchitis virus (ibv) is prevalent in all countries with an intensive poultry industry, with the incidence of infection approaching 100% in most locations. vaccination is only partially successful due to the continual emergence of antigenic variants. at many sites, multiple antigenic types are simultaneously present, requiring the application of multiple vaccines. although many countries share some common antigenic types, ibv strains within a geographic region are unique and distinct ... | 2000 | 10935276 |
| detection of antibody to turkey coronavirus by antibody-capture enzyme-linked immunosorbent assay utilizing infectious bronchitis virus antigen. | an antibody-capture enzyme-linked immunosorbent assay (elisa) for detection of antibody to turkey coronavirus (tcv) utilizing infectious bronchitis virus (ibv) antigen was developed. anti-tcv hyperimmune turkey serum and normal turkey serum were used as positive or negative control serum for optimization of the elisa system. goat anti-turkey immunoglobulin g (light plus heavy chains) conjugated with horseradish peroxidase was used as detector antibody. the performance of the elisa system was eva ... | 2000 | 11006996 |
| morphologic observations on respiratory tracts of chickens after hatchery infectious bronchitis vaccination and formaldehyde fumigation. | the histologic changes in the respiratory tracts of chickens were evaluated after hatchery fumigation with 40% formaldehyde vapors and vaccination against infectious bronchitis virus with live attenuated vaccine (massachusetts serotype). one-day-old chickens were housed in four isolation units in controlled environmental conditions, fed and watered ad libitum, and separated into four groups: 1) fumigated and vaccinated birds (fv group); 2) nonfumigated and vaccinated birds (nfv group); 3) fumiga ... | 2000 | 11006997 |
| protective immunity to infectious bronchitis in broilers vaccinated against marek's disease either in ovo or at hatch and against infectious bronchitis at hatch. | two experiments were conducted using commercial broiler chickens to determine if marek's disease (md) vaccines hvt/sb-1 and hvt plus cvi-988 given either in ovo or at hatch adversely affected the efficacy of infectious bronchitis (ib) vaccines (ark and mass serotypes) given by eyedrop on the day of hatch. nonvaccinated negative controls and controls that received only ib vaccines were included in each study. birds were challenged with either infectious bronchitis virus (ibv) mass-41 or ibv ark-9 ... | 2000 | 11007000 |
| emergence of subtype strains of the arkansas serotype of infectious bronchitis virus in delmarva broiler chickens. | infectious bronchitis virus (ibv) field isolates of the arkansas (ark) serotype were identified by reverse transcription-polymerase chain reaction (rt-pcr) as the most common serotype isolated from 1993 to 1997. these isolates were recovered from broiler flocks with respiratory disease raised on the delmarva peninsula in spite of ark vaccination in the region. for the purposes of investigating this apparently paradoxical finding, five rt-pcr ark-positive field isolates recovered in 1995 and 1996 ... | 2000 | 11007004 |
| characterization of infectious bronchitis viruses isolated from outbreaks of disease in commercial flocks in brazil. | fifteen isolations of infectious bronchitis (ib) virus were made from a total of 126 brazilian poultry flocks of all ages that were examined. these flocks (14 chicken and 1 quail) were experiencing a variety of ib-like conditions including respiratory disease, digestive and kidney problems, and drops in egg production. one of the isolates was of the massachusetts serotype. the remainder were examined by means of cross-neutralization tests in tracheal organ cultures and were shown to belong to at ... | 2000 | 11007005 |
| redesign of primer and application of the reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism test to the de072 strain of infectious bronchitis virus. | diagnosis of the de072 strain of infectious bronchitis virus (ibv) by the reverse transcriptase-polymerase chain reaction (rt-pcr) and restriction fragment length polymorphism (rflp) serotype identification test was not possible because the primer used in the rt-pcr did not amplify the s1 gene of the de072 strain. the 3' end of the polymerase gene and the 5' end of the s2 gene of the de072 strain were sequenced and compared with the forward and reverse rt-pcr primers, respectively. a 2-bp mismat ... | 2000 | 11007014 |
| utilizing fowlpox virus recombinants to generate defective rnas of the coronavirus infectious bronchitis virus. | coronavirus defective rnas (d-rnas) have been used as rna vectors for the expression of heterologous genes and as vehicles for reverse genetics by modifying coronavirus genomes by targetted recombination. d-rnas based on the avian coronavirus infectious bronchitis virus (ibv) d-rna cd-61 have been rescued (replicated and packaged into virions) in a helper virus-dependent manner following electroporation of in vitro-generated t7 transcripts into ibv-infected cells. in order to increase the effici ... | 2000 | 11086116 |
| evidence of genetic diversity generated by recombination among avian coronavirus ibv. | previously, we demonstrated that the de072 strain of ibv is a recombinant which has an ibv strain d1466-like sequence in the s gene. herein, we analyzed the remaining 3.8 kb 3' end of the genome, which includes gene 3, gene 4, gene 5, gene 6, and the 3' non-coding region of the de072 and d1466 strains. those two viruses had high nucleotide similarity in gene 4. however, the other individual genes had a much different level of sequence similarity with the same gene of the other ibv strains. the g ... | 2000 | 11087096 |
| antigen quantification as in vitro alternative for potency testing of inactivated viral poultry vaccines. | routine batch control of licensed inactivated viral vaccines for poultry usually includes a potency assay as a measure of vaccine efficacy. potency assays often consist of vaccination-challenge experiments in the target species or in laboratory animals. instead of measuring the protection of vaccinated animals against virulent pathogens, the serological response after vaccination can be quantified for some vaccines. in vitro antigen quantification assays would be attractive alternatives for the ... | 2000 | 11087135 |
| cis-acting sequences required for coronavirus infectious bronchitis virus defective-rna replication and packaging. | the parts of the rna genome of infectious bronchitis virus (ibv) required for replication and packaging of the rna were investigated using deletion mutagenesis of a defective rna (d-rna) cd-61 (6.1 kb) containing a chloramphenicol acetyltransferase reporter gene. a d-rna with the first 544, but not as few as 338, nucleotides (nt) of the 5' terminus was replicated; the 5' untranslated region (utr) comprises 528 nt. region i of the 3' utr, adjacent to the nucleocapsid protein gene, comprised 212 n ... | 2001 | 11119581 |
| the coronavirus infectious bronchitis virus nucleoprotein localizes to the nucleolus. | the coronavirus nucleoprotein (n) has been reported to be involved in various aspects of virus replication. we examined by confocal microscopy the subcellular localization of the avian infectious bronchitis virus n protein both in the absence and in the context of an infected cell and found that n protein localizes both to the cytoplasmic and nucleolar compartments. | 2001 | 11119619 |
| a serological survey for avian infectious bronchitis virus and newcastle disease virus antibodies in backyard (free-range) village chickens in mexico. | the commercial flocks in yucatan, mexico are free of newcastle disease virus (ndv) in its velogenic viscerotropic form, but little is known about the disease status of backyard poultry. a seroprevalence survey in 30 villages using haemagglutination inhibition (hi) tests for infectious bronchitis virus (ibv) and ndv antibodies was carried out from december 1997 to june 1998. the seroprevalences were 56.5% (95% ci 50-63%) for ibv and 2.2% (95% ci 0.5-3.8%) for ndv. all the villages had chickens th ... | 2000 | 11147278 |
| effect of liquid paraffin on antibody responses and local adverse reactions of bivalent oil adjuvanted vaccines containing newcastle disease virus and infectious bronchitis virus. | effects of liquid paraffin on antibody responses and local adverse reactions after intramuscular injection of oil adjuvanted vaccines containing newcastle disease (nd) and infectious bronchitis (ib) virus were investigated in chickens. each vaccine was prepared with a liquid paraffin such as carnation, crystol 52 and lytol. these vaccines induced sustained antibody responses against nd and ib. among local adverse reactions, lytol induced granulomatous reactions and abscesses, but carnation and c ... | 2000 | 11193350 |
| serological monitoring on layer farms with specific pathogen-free chickens. | to monitor the existence of avian pathogens in laying chicken flocks, specific pathogen-free (spf) chickens were introduced into two layer farms and reared with laying hens for 12 months. spf chickens were bled several times after their introduction and examined for their sero-conversion to avian pathogens. as a result, antibodies to eight or ten kinds of pathogens were detected in spf chickens on each farm. antibodies to infectious bronchitis virus (ibv), avian nephritis virus, mycoplasma galli ... | 2000 | 11193353 |
| molecular characterization of an infectious bronchitis virus strain isolated from an outbreak in vaccinated layers. | an infectious bronchitis virus (ibv) strain ct/7852/97 was isolated from a commercial layer flock experiencing decreased egg production and poor egg quality. reciprocal virus neutralization test demonstrated that the isolate was closely related to massachusetts, arkansas, and jmk. with the use of both reverse transcription-polymerase chain reaction-restriction fragment length polymorphism and multiplex polymerase chain reaction methods, results consistently showed that ct/7852/97 isolate was mas ... | 2000 | 11195625 |
| experimental escherichia coli respiratory infection in broilers. | this study determined optimal conditions for experimental reproduction of colibacillosis by aerosol administration of avian pathogenic escherichia coli to 2-to-4-wk-old broiler chickens. the basic model for reproducing disease was intranasal administration of approximately 10(4) mean embryo infectious dose of infectious bronchitis virus (ibv) followed by aerosol administration of an 02 or an 078 strain of e. coli in a horsfall unit (100 ml of a suspension of 10(9) colony-forming units/ml over 40 ... | 2000 | 11195629 |
| characterization of mexican strains of avian infectious bronchitis isolated during 1997. | ten infectious bronchitis virus (ibv) isolates were recovered from broiler chickens in the states of queretaro and guanajuato in mexico. the viruses were isolated from trachea, lung, kidney, and cecal tonsils of birds that showed respiratory signs in spite of vaccination with massachusetts (mass) and connecticut strains of ibv. each isolate was identified by an accession number from 1 to 10. six of the isolates were neutralized by mass monoclonal antibodies, whereas the other four were not. in a ... | 2000 | 11195651 |
| spike gene analysis of the de072 strain of infectious bronchitis virus: origin and evolution. | the entire s2 gene of the de072 strain of infectious bronchitis virus (ibv) was sequenced. the nucleotide and amino acid sequence was most similar to the d1466 strain and was 84.8% and 89.9% identity, respectively. the nucleotide and amino acid sequence similarity among the de072 strain and other ibv strains was less than 71.9% and 76.6%, respectively. phylogenetic analysis, based on both nucleotide and amino acid sequence, showed that ibv isolates were divided into two distinct groups. the de07 ... | 2001 | 11210943 |
| the missing link in coronavirus assembly. retention of the avian coronavirus infectious bronchitis virus envelope protein in the pre-golgi compartments and physical interaction between the envelope and membrane proteins. | one missing link in the coronavirus assembly is the physical interaction between two crucial structural proteins, the membrane (m) and envelope (e) proteins. in this study, we demonstrate that the coronavirus infectious bronchitis virus e can physically interact, via a putative peripheral domain, with m. deletion of this domain resulted in a drastic reduction in the incorporation of m into virus-like particles. immunofluorescent staining of cells coexpressing m and e supports that e interacts wi ... | 2001 | 11278557 |
| baculovirus expression of turkey coronavirus nucleocapsid protein. | the nucleocapsid (n) gene of turkey coronavirus (tcv) was amplified by reverse transcriptase-polymerase chain reaction, cloned, and expressed in the baculovirus expression system. a recombinant baculovirus containing the tcv n gene (rbtcv/n) was identified by polymerase chain reaction and expression of tcv n protein as determined by western immunoblot analysis. two tcv-specific proteins, 52 and 43 kda, were expressed by rbtcv/n; one of these proteins, p52, was comparable in size to native tcv n ... | 2001 | 11332474 |
| identification and analysis of the georgia 98 serotype, a new serotype of infectious bronchitis virus. | twenty-five field infectious bronchitis viruses (ibvs) similar to, but genetically distinct from, the de072 serotype were isolated from several states in the united states from 1990 through 1999 and were examined molecularly and antigenically. a 421-bp sequence in the hypervariable region of the s1 gene was examined, and phylogenetic analysis on that region indicated that these viruses are closely related but fall into unique groups. cross-virus neutralization testing and entire s1 sequence anal ... | 2001 | 11332478 |
| molecular epidemiology of infectious bronchitis virus isolates from china and southeast asia. | in order to trace the origin and evolution of avian infectious bronchitis virus (ibv) isolates in china and southeast asia, genomic sequencing was used for molecular characterization of 24 ibv isolates and two reference strains in comparison with the published sequences. the 5' region of the s1 genes, containing hypervariable regions i and ii, and 3' region of the nucleocapsid genes, containing cytotoxic t lymphocyte epitopes, were used to construct phylogenetic trees for analysis. the results s ... | 2001 | 11332484 |
| the exacerbating effect of infectious bronchitis virus infection on the infectious bursal disease virus-induced suppression of opsonization by escherichia coil antibody in chickens. | chickens infected with infectious bronchitis virus (ibv) and infectious bursal disease virus (ibdv) commonly develop secondary infection of the respiratory tract with escherichia coli, resulting in significant economic losses. to understand the host factors that may contribute to the e. coli infection, we investigated macrophage-mediated e. coli phagocytosis, intracellular bacterial killing, and development of opsonizing antibody in previously uninfected chickens and in those infected with ibv, ... | 2001 | 11332499 |
| maternal antibody to infectious bronchitis virus: its role in protection against infection and development of active immunity to vaccine. | chicks hatched with high levels of maternal antibody had excellent protection (>95%) against infectious bronchitis virus (ibv) challenge at 1 day of age, but not at 7 days (<30%). this protection significantly (p<0.05) correlated with levels of local respiratory antibody and not with serum antibody.a high percentage of both maternal antibody-positive (mab+) and maternal antibody-negative (mab-) chicks failed to produce ibv antibody when vaccinated at 1 day of age by the intraocular route. in add ... | 2001 | 11356248 |
| nucleocapsid protein gene sequence analysis reveals close genomic relationship between turkey coronavirus and avian infectious bronchitis virus. | antibodies to infectious bronchitis virus (ibv) cross-react with turkey coronavirus (tcv) in immunofluorescence assay (ifa) indicating that ibv and tcv may share an amino acid sequence similarity. to determine its extent, the gene encoding the nucleocapsid (n) protein of tcv was amplified by reverse transcription-pcr (rt-pcr) from rna purified from intestines of embryos of turkeys infected with various tcv isolates and from allantoic fluid of chicken embryos infected with ibv m41 strain, the obt ... | 2001 | 11394575 |
| induction of caspase-dependent apoptosis in cultured cells by the avian coronavirus infectious bronchitis virus. | avian coronavirus infectious bronchitis virus (ibv) is the causative agent of chicken infectious bronchitis, an acute, highly contagious viral respiratory disease. replication of ibv in vero cells causes extensive cytopathic effects (cpe), leading to destruction of the entire monolayer and the death of infected cells. in this study, we investigated the cell death processes during acute ibv infection and the underlying mechanisms. the results show that both necrosis and apoptosis may contribute t ... | 2001 | 11413307 |
| study of protection by recombinant fowl poxvirus expressing c-terminal nucleocapsid protein of infectious bronchitis virus against challenge. | a stable recombinant fowl poxvirus (rfpv) expressing the c-terminal region (119 amino acids) of the nucleocapsid (n) protein of an infectious bronchitis virus (ibv) strain ch3 was constructed by inserting the coding sequence within the thymidine kinase gene of fowl poxvirus (fpv) by homologous recombination. the n protein was expressed under control of the vaccinia virus promoter p7.5 in chicken embryo fibroblast cell cultures as seen in immunofluorescence assay and in rfpv-inoculated specific-p ... | 2001 | 11417813 |
| spike glycoprotein cleavage recognition site analysis of infectious bronchitis virus. | the spike glycoprotein of infectious bronchitis virus (ibv), a coronavirus, is translated as a precursor protein (so), then cleaved into two subunits (s1 and s2) by host cell serine proteases. in this study, we compared the cleavage recognition site of 55 ibv isolates to determine if the cleavage recognition site sequence, which consists of five basic amino acid residues, correlates with host cell range, serotype, geographic origin, and pathogenicity as it does in orthomyxoviruses and paramyxovi ... | 2001 | 11417816 |
| characterization of three infectious bronchitis virus isolates from china associated with proventriculus in vaccinated chickens. | outbreaks of an avian disease in infectious bronchitis-vaccinated chickens in china have led to the characterization of coronaviral isolates q1, j2, and t3, which were isolated from proventricular tissues of the affected young layer flocks. serologic analysis revealed that they could induce high titers of infectious bronchitis virus (ibv) antibodies in inoculated specific-pathogen-free (spf) chickens in indirect enzyme-linked immunosorbent assay but were not neutralized by antisera specific to t ... | 2001 | 11417821 |
| molecular characterization of infectious bronchitis virus isolates foreign to the united states and comparison with united states isolates. | eleven infectious bronchitis virus (ibv) isolates foreign to the united states were analyzed by using reverse transcriptase (rt)-polymerase chain reaction (pcr)/restriction fragment length polymorphism (rflp) and s1 glycoprotein gene sequencing. two of the isolates generated rflp patterns that resembled the mass 41 strain. seven novel rflp patterns were detected among the other nine foreign ibv isolates. five of the foreign isolates were further analyzed by s1 glycoprotein gene sequencing in our ... | 2001 | 11417834 |
| the autocatalytic release of a putative rna virus transcription factor from its polyprotein precursor involves two paralogous papain-like proteases that cleave the same peptide bond. | the largest replicative protein of coronaviruses is known as p195 in the avian infectious bronchitis virus (ibv) and p210 (p240) in the mouse hepatitis virus. it is autocatalytically released from the precursors pp1a and pp1ab by one zinc finger-containing papain-like protease (plpro) in ibv and by two paralogous plpros, pl1pro and pl2pro, in mouse hepatitis virus. the plpro-containing proteins have been recently implicated in the control of coronavirus subgenomic mrna synthesis (transcription). ... | 2001 | 11431476 |
| localization to the nucleolus is a common feature of coronavirus nucleoproteins, and the protein may disrupt host cell division. | the subcellular localization of transmissible gastroenteritis virus (tgev) and mouse hepatitis virus (mhv) (group i and group ii coronaviruses, respectively) nucleoproteins (n proteins) were examined by confocal microscopy. the proteins were shown to localize either to the cytoplasm alone or to the cytoplasm and a structure in the nucleus. this feature was confirmed to be the nucleolus by using specific antibodies to nucleolin, a major component of the nucleolus, and by confocal microscopy to im ... | 2001 | 11533198 |
| infectious bronchitis serology in broilers and broiler breeders: correlations between antibody titers and performance in vaccinated flocks. | in this study, a follow-up was made between 1993 and 1997 from broiler breeders at birth down to offspring broilers at processing, through vertically integrated registration of infectious bronchitis virus (ibv) antibody titers and performance data. all measurements were used two by two in a simple correlation study to calculate the degree to which they were linearly correlated. the antibody patterns in the broiler breeders indicated frequent field infections breaking through vaccinal immunity. s ... | 2001 | 11569734 |
| cases of swollen head syndrome in broiler chickens in greece. | from 50 commercial broiler flocks included in a study concerning respiratory disease, signs of swollen head syndrome (shs) were shown in eight. postmortem examination was performed in eight birds showing signs of shs from each flock. the trachea and head from each bird were collected for laboratory investigation. an enzyme-linked immunosorbent assay (elisa) was used for the detection of viral and avian mycoplasma antigens in the trachea, and bacteriologic examinations were performed from the inf ... | 2001 | 11569754 |
| origin and evolution of georgia 98 (ga98), a new serotype of avian infectious bronchitis virus. | we previously identified ga98, a new serotype of infectious bronchitis virus (ibv), which is closely related to the de072 serotype of ibv genetically, but not antigenically. herein, we analyzed the 421bp sequence of a hypervariable region (hvr) (position 114-534, counting from the atg start site) of the s1 subunit of ga98 ibvs to further examine the evolution of these viruses. these viruses were isolated between the years 1997 and 2000. phylogenetic analysis of the deduced amino acid sequence on ... | 2001 | 11597746 |
| further identification and characterization of novel intermediate and mature cleavage products released from the orf 1b region of the avian coronavirus infectious bronchitis virus 1a/1b polyprotein. | the coronavirus 3c-like proteinase is one of the viral proteinases responsible for processing of the 1a and 1a/1b polyproteins to multiple mature products. in cells infected with avian coronavirus infectious bronchitis virus (ibv), three proteins of 100, 39, and 35 kda, respectively, were previously identified as mature cleavage products released from the 1b region of the 1a/1b polyprotein by the 3c-like proteinase. in this report, we show the identification of two more cleavage products of 68 a ... | 2001 | 11601893 |
| reverse genetics system for the avian coronavirus infectious bronchitis virus. | major advances in the study of the molecular biology of rna viruses have resulted from the ability to generate and manipulate full-length genomic cdnas of the viral genomes with the subsequent synthesis of infectious rna for the generation of recombinant viruses. coronaviruses have the largest rna virus genomes and, together with genetic instability of some cdna sequences in escherichia coli, this has hampered the generation of a reverse-genetics system for this group of viruses. in this report, ... | 2001 | 11711626 |
| ribosomal pausing at a frameshifter rna pseudoknot is sensitive to reading phase but shows little correlation with frameshift efficiency. | here we investigated ribosomal pausing at sites of programmed -1 ribosomal frameshifting, using translational elongation and ribosome heelprint assays. the site of pausing at the frameshift signal of infectious bronchitis virus (ibv) was determined and was consistent with an rna pseudoknot-induced pause that placed the ribosomal p- and a-sites over the slippery sequence. similarly, pausing at the simian retrovirus 1 gag/pol signal, which contains a different kind of frameshifter pseudoknot, also ... | 2001 | 11713298 |
| completion of the porcine epidemic diarrhoea coronavirus (pedv) genome sequence. | the sequence of the replicase gene of porcine epidemic diarrhoea virus (pedv) has been determined. this completes the sequence of the entire genome of strain cv777, which was found to be 28,033 nucleotides (nt) in length (excluding the poly a-tail). a cloning strategy, which involves primers based on conserved regions in the predicted orf1 products from other coronaviruses whose genome sequence has been determined, was used to amplify the equivalent, but as yet unknown, sequence of pedv. primary ... | 2001 | 11724265 |
| growth and immunity of broiler chicks as affected by dietary arginine. | a dietary deficiency of arg may suppress chick immune system functions; however, research evaluating immune function responsiveness of commercial broilers fed dietary arg levels near nrc (1994) recommendations is sparse. therefore, three experiments were conducted to evaluate growth and immunity of broilers fed varying arg levels near nrc (1994) specifications. because arg and lys are similar in structure and are known to compete in intestinal absorption, dietary lys treatments [near nrc (1994) ... | 2001 | 11732668 |
| relationship between the level of dietary vitamin e and the immune response of broiler chickens. | the relationship between the dietary level of vitamin e (ve) and the immune response of broilers was studied in three experiments. immunity was assessed as antibody production to infectious bronchitis virus (ibv), srbc, and brucella abortus (ba) antigens, mitogenic response to phytohemagglutinin a (pha) and concanavalin a (con a), cutaneous basophil hypersensitivity (cbh) to pha, and lipopolysaccharide induction of acute-phase proteins (app) and heterophilia. a range of ve (0, 10, 17.5, 25, 37.5 ... | 2001 | 11732676 |
| the cytoplasmic tail of infectious bronchitis virus e protein directs golgi targeting. | we have previously shown that the e protein of the coronavirus infectious bronchitis virus (ibv) is localized to the golgi complex when expressed exogenously from cdna. here, we report that neither the transmembrane domain nor the short lumenal domain of ibv e is required for golgi targeting. however, an n-terminal truncation containing only the cytoplasmic domain (cte) was efficiently localized to the golgi complex, and this domain could retain a reporter protein in the golgi. thus, the cytopla ... | 2002 | 11773403 |
| further identification and characterization of products processed from the coronavirus avian infectious bronchitis virus (ibv) 1a polyprotein by the 3c-like proteinase. | | 2001 | 11774483 |
| enhancement of defective rna expression vectors as potential vaccine delivery systems for avian infectious bronchitis virus. | | 2001 | 11774500 |
| use of an infectious bronchitis virus d-rna as an rna vector. | | 2001 | 11774515 |
| use of defective rnas containing reporter genes to investigate targeted recombination for avian infectious bronchitis virus. | | 2001 | 11774516 |
| functional ibv minigenomes generated by recombinant fowl pox viruses for use in ibv-targeted recombination studies. | | 2001 | 11774520 |
| sequences required for replication and packaging of ibv rna. | | 2001 | 11774523 |
| characterization of temperature-sensitive (ts) mutants of coronavirus infectious bronchitis virus (ibv). | | 2001 | 11774524 |
| infectious bronchitis virus envelope protein targeting: implications for virus assembly. | | 2001 | 11774527 |
| physical interaction between the membrane (m) and envelope (e) proteins of the coronavirus avian infectious bronchitis virus (ibv). | | 2001 | 11774531 |
| infectious bronchitis virus nucleocapsid protein interactions with the 3' untranslated region of genomic rna depend on uridylate bases. | | 2001 | 11774543 |
| isolation and characterization of a novel antigenic subtype of infectious bronchitis virus serotype de072. | three infectious bronchitis virus (ibv) isolates, cu82792, cu82805, and cu82808, were recovered from sentinel chickens placed with three different layer flocks of a large commercial poultry farm in new york state. the three isolates were classified as members of the de072 serotype on the basis of 1) their s1 genes could be amplified with only a modified primer designed for the de072 serotype and 2) their restriction fragment length polymorphism patterns, after digestion with endonucleases haeiii ... | 2001 | 11785878 |
| novel infectious bronchitis virus s1 genotypes in mexico 1998-1999. | seventeen infectious bronchitis virus (ibv) field isolates recovered from commercial broiler flocks in mexico were identified by reverse transcription-polymerase chain reaction cycle sequencing of the s1 gene. the isolates were obtained from broilers on farms from the neighboring states of queretaro and san luis potosi in 1998 and 1999. flocks had an ongoing history of bacterial-complicated respiratory disease with mortality rates as high as 28% in spite of receiving live vaccinations for massac ... | 2001 | 11785879 |
| antigenic and genomic relatedness of turkey-origin coronaviruses, bovine coronaviruses, and infectious bronchitis virus of chickens. | in earlier studies in our laboratory, we found that bovine coronavirus (bcv) was pathogenic for 1-day-old turkey poults. this finding prompted us to study the antigenic and genomic relatedness of turkey origin coronaviruses (tocvs) to bcv. a one-step reverse transcription (rt)-polymerase chain reaction (pcr) targeting a 730-base pair fragment of the nucleocapsid (n) gene of bcv and a nested pcr targeting a 407-base pair fragment of the n gene were used in an attempt to detect tocv from north car ... | 2001 | 11785902 |
| chicken interferon type i inhibits infectious bronchitis virus replication and associated respiratory illness. | infectious bronchitis virus (ibv) causes an economically important respiratory disease in poultry worldwide. previous studies have shown that cd8(+) cytotoxic t lymphocytes (ctl) are critical in controlling acute ibv infection, but the role of innate immunity is unknown. this study describes the in vitro and in vivo anti-ibv activity of natural spleen cell-derived and recombinant chicken interferon type i (rchifn-alpha). both natural and rchifn-alpha inhibited replication of the beaudette strain ... | 2001 | 11798465 |
| identification, expression, and processing of an 87-kda polypeptide encoded by orf 1a of the coronavirus infectious bronchitis virus. | nucleotide sequence analysis has shown previously that the genomic-length mrna (mrna1) of the coronavirus infectious bronchitis virus (ibv) contains two large open reading frames (orfs), 1a and 1b, with the potential to encode polyproteins of approximately 441 and 300 kda, respectively. we have characterized the specificity of a set of region-specific antisera raised against the 5'-portion of orf 1a by immunoprecipitation of in vitro-synthesized, c-terminally truncated 1a polypeptides and used t ... | 1995 | 11831730 |
| conservation of substrate specificities among coronavirus main proteases. | the key enzyme in coronavirus replicase polyprotein processing is the coronavirus main protease, 3cl(pro). the substrate specificities of five coronavirus main proteases, including the prototypic enzymes from the coronavirus groups i, ii and iii, were characterized. recombinant main proteases of human coronavirus (hcov), transmissible gastroenteritis virus (tgev), feline infectious peritonitis virus, avian infectious bronchitis virus and mouse hepatitis virus (mhv) were tested in peptide-based t ... | 2002 | 11842254 |
| an elisa for antibodies against infectious bronchitis virus using an s1 spike polypeptide. | using the whole infectious bronchitis virus (ibv) for detecting the antibody against ibv by enzyme-linked immunosorbent assay (elisa) is a routine work in poultry industry. to prepare virus is time consuming and tedious. furthermore, the whole viral antigen detects all antibodies against the viral structural proteins, including spike (s), nucleocapsid, matrix, and other proteins. among those, s protein is related to neutralization. thus, to develop and express protein fragment from s gene and to ... | 2002 | 11856583 |
| antibody responses and morbidity following infection with infectious bronchitis virus and challenge with escherichia coli, in lines divergently selected on antibody response. | we evaluated the association between antibody (ab) production and disease resistance. a controlled-challenge protocol was developed to mimic natural infection and to yield a higher rate of mortality following escherichia coli (ec) challenge. chicks were first infected with infectious bronchitis virus (ibv) by injecting a high dose of vaccine (attenuated virus) into their air sacs and then were infected with pathogenic ec introduced intratracheally. the experimental population consisted of lines ... | 2002 | 11873823 |
| embryonic exposure to lead: comparison of immune and cellular responses in unchallenged and virally stressed chickens. | lead, a ubiquitous environmental contaminant, has been shown to modulate various functions of the immune system and decrease host resistance to infectious disease. however, limited information is available concerning the direct effects of lead on the host immune response to an infectious agent after developmental exposure. the current study utilized chickens to examine the effect of embryonic lead exposure on immune and cellular responses during viral challenge. sublethal doses of lead were intr ... | 2002 | 11876505 |
| changes in serum ovotransferrin levels in chickens with experimentally induced inflammation and diseases. | a competitive enzyme immunoassay was developed to measure the changes in serum levels of ovotransferrin (otf) during inflammation and infectious diseases in chickens. the assay is based on the competition of serum otf with a fixed concentration of biotin-labeled otf to bind to a rabbit anti-chicken transferrin antibody immobilized on microtiter wells. after several washing steps, the antibody-bound biotinylated otf is probed with streptavidin-horseradish peroxidase conjugate (hrp) followed by a ... | 2002 | 11922323 |
| pathogenicity of australian strains of avian infectious bronchitis virus. | the pathogenicity of 25 strains of infectious bronchitis virus (ibv) isolated in australia between 1961 and 1994 was compared in white leghorn specific pathogen-free chicks. twelve strains were nephropathogenic and 10 respiratory, the other three being of mixed pathogenicity. the ibv strains identified as nephropathogenic induced clinical nephritis, gross and histological kidney lesions, and mortality of 5-90%. according to the severity of these features, the nephropathogenic strains could be fu ... | 2002 | 11945000 |
| interaction of the coronavirus nucleoprotein with nucleolar antigens and the host cell. | coronavirus nucleoproteins (n proteins) localize to the cytoplasm and the nucleolus, a subnuclear structure, in both virus-infected primary cells and in cells transfected with plasmids that express n protein. the nucleolus is the site of ribosome biogenesis and sequesters cell cycle regulatory complexes. two of the major components of the nucleolus are fibrillarin and nucleolin. these proteins are involved in nucleolar assembly and ribosome biogenesis and act as chaperones for the import of prot ... | 2002 | 11967337 |
| membrane association and dimerization of a cysteine-rich, 16-kilodalton polypeptide released from the c-terminal region of the coronavirus infectious bronchitis virus 1a polyprotein. | more than 10 mature proteins processed from coronavirus gene 1-encoded polyproteins have been identified in virus-infected cells. here, we report the identification of the most c-terminal cleavage product of the 1a polyprotein as a 16-kda protein in infectious bronchitis virus-infected vero cells. indirect immunofluorescence demonstrated that the protein exhibits a distinct perinuclear punctate staining pattern, suggesting that it is associated with cellular membranes. positive staining observed ... | 2002 | 12021359 |
| infectious agents associated with respiratory disease in pheasants. | in a case-control study of the infectious agents associated with natural outbreaks of respiratory disease in pheasants, 28 batches of birds from sites affected by disease and eight batches of birds from unaffected sites were examined by six veterinary laboratories in england, wales and scotland, and tested for mycoplasmas, other bacteria and viruses. sinusitis was the commonest sign of disease and was associated with mycoplasma gallisepticum as detected by pcr in the trachea (p < 0.05) and conju ... | 2002 | 12054135 |
| development of a competitive enzyme-linked immunosorbent assay for detection of turkey coronavirus antibodies. | a competitive enzyme-linked immunosorbent assay (celisa) was developed for detection of turkey coronavirus (tcv) antibodies. the celisa utilized a recombinant baculovirus (autographa californica nuclear polyhedrosis virus)-expressed tcv nucleocapsid (n) protein and biotin-labeled tcv n protein-specific monoclonal antibody. sensitivity and specificity of the celisa for detection of tcv antibodies were determined by comparison with the indirect fluorescent antibody test (ifat) with 1269 reference, ... | 2002 | 12061642 |
| genetic and antigenic diversity in avian infectious bronchitis virus isolates of the 1940s. | in order to verify a commonly held assumption that only massachusetts (mass) serotype of infectious bronchitis virus (ibv) was prevalent in the united states between the 1930s (when ibv was first isolated) and the 1950s (when the use of commercial ibv vaccines began), we examined 40 ibv field isolates from the 1940s. thirty-eight of those isolates were recognized as mass serotype viruses based on their reactivity to mass-specific monoclonal antibody (mab) and neutralization by mass-specific chic ... | 2002 | 12061655 |
| antigenic relationship of turkey coronavirus isolates from different geographic locations in the united states. | the purpose of the present study was to examine the antigenicity of turkey coronavirus (tcv) isolates from various geographic areas with antibodies to different viruses. seventeen isolates of tcv were recovered from intestinal samples submitted to animal disease diagnostic laboratory, purdue university, from turkey farms located in different geographic areas. the prototype tcv minnesota isolate (tcv-atcc) was obtained from the american type culture collection. intestinal sections were prepared f ... | 2002 | 12061660 |
| dietary arginine intake alters avian leukocyte population distribution during infectious bronchitis challenge. | although dietary arginine is a factor in immune function and disease resistance, the full range of effects has yet to be described. in this study, the effects of dietary arginine on leukocyte population changes were examined in the peripheral blood and the respiratory tract of chickens inoculated with infectious bronchitis virus (ibv) strain m41. at 2 wk of age, female line p2a white leghorn-type chickens were randomly assigned to one of three diets with different arginine levels: a marginally d ... | 2002 | 12079045 |
| pulse and continuous oral norfloxacin treatment of experimentally induced escherichia coli infection in broiler chicks and turkey poults. | experimental colibacillosis was produced in 40 healthy, 7-day-old broiler chickens and turkeys by intratracheal injection of 1 x 10(8) cfu/chick and 1.23 x 10(9) cfu/poult bacteria of an o1:f11 strain of escherichia coli, respectively. two days before e. coli challenge all chicks were vaccinated with a live attenuated strain of infectious bronchitis virus (h-52). this model of infection--at least in chicken--proved to be useful for evaluating the efficacy of antimicrobial medication, by recordin ... | 2002 | 12113175 |
| molecular characterization of three new avian infectious bronchitis virus (ibv) strains isolated in quebec. | three unrecognized field isolates of infectious bronchitis virus (ibv) were recovered from commercial broiler chickens vaccinated with live mass viral strain (h120). these isolates were identified by immunofluorescence using monoclonal antibodies produced against reference serotypes: mass, conn, and ark. rt-pcrs were performed on viral rnas to amplify s1 gene using a specific set of primers s1oligo3' and s1oligo5'. restriction polymorphism (rflp) of pcr products was determined by the use of haei ... | 2002 | 12206312 |
| field trial in commercial broilers with a multivalent in ovo vaccine comprising a mixture of live viral vaccines against marek's disease, infectious bursal disease, newcastle disease, and fowl pox. | a multivalent in ovo vaccine (miv) was tested for safety and efficacy in a commercial broiler complex. the miv comprised five replicating live viruses including serotypes 1, 2, and 3 of marek's disease virus (mdv), an intermediate infectious bursal disease virus (ibdv) and a recombinant fowl poxvirus (fpv) vector vaccine containing hn and f genes of newcastle disease virus (ndv). the performance of miv-vaccinated broilers was compared with that of hatchmates that received turkey herpesvirus (hvt ... | 2002 | 12243525 |
| detection of in ovo-inoculated infectious bronchitis virus by immunohistochemistry and in situ hybridization with a riboprobe in epithelial cells of the lung and cloacal bursa. | in situ hybridization and immunohistochemistry were utilized to identify tissues infected in ovo with infectious bronchitis virus (ibv). chicken embryos were inoculated in ovo (chorioallantoic sac) with the arkansas (ark) serotype of ibv at 18 days of age. at 24, 48, 72, and 120 hr postinfection (hpi), bursa, lung, spleen, heart, and thymus were collected, fixed in 10% neutral buffered formalin, and paraffin embedded. the digoxigenin-labeled antisense s1 riboprobe detected viral mrna in the cyto ... | 2002 | 12243532 |
| development and application of a multiplex polymerase chain reaction for avian respiratory agents. | a multiplex polymerase chain reaction (pcr) was developed and optimized to simultaneously detect 6 avian respiratory pathogens. six sets of specific oligonucleotide primers for infectious bronchitis virus (ibv), avian influenza virus (aiv), infectious laryngotracheitis virus (iltv), newcastle disease virus (ndv), mycoplasma gallisepticum (mg), and mycoplasma synoviae (ms) were used respectively in the test. with the use of agarose gel electrophoresis for detection of the pcr-amplified dna produc ... | 2002 | 12243534 |
| tissue distribution of avian infectious bronchitis virus following in ovo inoculation of chicken embryos examined by in situ hybridization with antisense digoxigenin-labeled universal riboprobe. | chicken embryos were inoculated with 8 different strains of infectious bronchitis virus (ibv) representing 7 different serotypes at 17 days of embryonation. at 2 and 5 days postinfection (dpi), tissues were collected for in situ hybridization using an antisense digoxigenin-labeled riboprobe corresponding to the sequence of the mrna coding for the membrane protein. extensive antigen staining in the cytoplasm of epithelial cells in the trachea, lung, bursa, and intestine was detected at 2 dpi with ... | 2002 | 12296388 |
| response of pheasants to live attenuated turkey rhinotracheitis vaccine. | the entire crop of 18,120 pheasants for the 2000 rearing season (may 8 to august 7) of one estate in the south of england was vaccinated at one day and five weeks of age with a turkey rhinotracheitis (trt) vaccine. blood samples and oropharyngeal swabs were taken from the second week's hatching every three weeks throughout the growing season to assess the response of the birds. there was evidence of seroconversion in samples collected three weeks after vaccination, with positive titres being mai ... | 2002 | 12371689 |
| existence of gene 5 indicates close genomic relationship of turkey coronavirus to infectious bronchitis virus. | a segment of genomic rna extending from the 3'-end of the membrane (m) protein gene to the 5'-end of the nucleocapsid (n) protein gene of turkey coronavirus (tcv) was amplified by reverse transcription-polymerase chain reaction (rt-pcr). the primers were derived from the corresponding sequences of infectious bronchitis virus (ibv). the pcr products were cloned and sequenced and their nucleic acid structure and similarity to the published sequences of ibv were analyzed. gene 5 containing two over ... | 2002 | 12387503 |
| molecular epizootiology of infectious bronchitis virus in sweden indicating the involvement of a vaccine strain. | to improve the detection and molecular identification of infectious bronchitis virus (avian coronavirus), two reverse transcriptase-polymerase chain reaction (pcr) assays were developed. as 'diagnostic#10; pcr', a set of consensus nested primers was selected from highly conserved stretches of the nucleocapsid (n) gene. as 'phylogeny' pcr, a fragment of the spike protein gene (s1) was amplified and the pcr products were directly sequenced. to study the phylogenetic relationships of the viruses fr ... | 2002 | 12396345 |
| natural cases and an experimental study of h9n2 avian influenza in commercial broiler chickens of iran. | since 1998, an epidemic of avian influenza has occurred in the iranian poultry industry. the agent was pathotyped as non-highly pathogenic and subtyped as an h9n2 avian influenza virus. therefore it did not require eradication. however, frequent incidences of high mortality were observed commonly on broiler farms. no other species of bird were affected. the circulation of the virus and mixed infection with other respiratory pathogens, particularly infectious bronchitis virus and mycoplasma galli ... | 2002 | 12396348 |
| the role of feline aminopeptidase n as a receptor for infectious bronchitis virus. brief review. | feline aminopeptidase n (fapn) has been shown to serve as a receptor for feline, canine, porcine and human coronaviruses. our objective was to determine if fapn can serve as a receptor for infectious bronchitis virus (ibv). feline kidney cells that express fapn and hamster kidney fibroblasts that do not express fapn were inoculated with ibv and monitored for replication by indirect fluorescent assay and confocal microscopy and in chicken embryonated eggs. the results showed that the feline cells ... | 2002 | 12417943 |
| coronaviruses from pheasants (phasianus colchicus) are genetically closely related to coronaviruses of domestic fowl (infectious bronchitis virus) and turkeys. | reverse-transcriptase polymerase chain reactions (rt-pcrs) were used to examine rna extracted from mouth/nasal swabs from pheasants exhibiting signs of respiratory disease. the oligonucleotides used were based on sequences of infectious bronchitis virus (ibv), the coronavirus of domestic fowl. a rt-pcr for the highly conserved region ii of the 3' untranslated region of the ibv genome detected a coronavirus in swabs from 18/21 estates. sequence identity with the corresponding region of ibvs and c ... | 2002 | 12425795 |
| gastric gross and microscopic lesions caused by the unam-97 variant strain of infectious bronchitis virus after the eighth passage in specific pathogen-free chicken embryos. | herein we report a description of gross and microscopic lesions found in specific pathogen-free chicken embryos caused by unam-97 infectious bronchitis virus (ibv) variant strain after the eighth passage. embryos were divided into three groups and were inoculated in the chorioallantoic sac with 0.2 ml of unam-97, mass 41 ibv (positive control), or sterile pbs (negative control). forty-eight hours later the allatoic fluid was taken and used to start a cycle of eight passages through 9-d-old embry ... | 2002 | 12455591 |
| construction and immunogenicity studies of recombinant fowl poxvirus containing the s1 gene of massachusetts 41 strain of infectious bronchitis virus. | the spike 1 (s1) surface glycoprotein of infectious bronchitis virus (ibv) is the major inducer of the generation of virus neutralizing antibodies, and the administration of purified s1 has been shown to elicit a protective immune response against virulent virus challenge. on the basis of these observations, recombinant fowl poxvirus (rfpv) containing a cdna copy of the s1 gene of ibv mass 41 (rfpv-s1) was constructed and its immunogenicity and vaccine potential were evaluated. initially, rfpv-s ... | 2002 | 12495043 |
| nephropathogenic infectious bronchitis in pennsylvania chickens 1997-2000. | nephropathogenic infectious bronchitis (nib) was diagnosed in 28 infectious bronchitis virus (ibv)-vaccinated commercial chicken flocks in pennsylvania from december 1997 to july 2000. early dinical signs were increased flock mortality and urinary water loss (polyuria and pollakiuria) leading to wet litter. daily mortality ranged from 0.01% in layers to 2.45% in broilers, with total broiler mortality as high as 23%. severe renal swelling and accumulation of urates in the tubules were commonly se ... | 2002 | 12495045 |
| protection of chickens after live and inactivated virus vaccination against challenge with nephropathogenic infectious bronchitis virus pa/wolgemuth/98. | protection provided by live and inactivated virus vaccination against challenge with the virulent nephropathogenic infectious bronchitis virus (nibv) strain pa/wolgemuth/98 was assessed. vaccinations with combinations of live attenuated strains massachusetts (mass) + connecticut (conn) or mass + arkansas (ark) were given by eyedrop to 2-wk-old specific-pathogen-free leghorn chickens. after live infectious bronchitis virus (ibv) vaccination, some chickens at 6 wk of age received an injection of e ... | 2002 | 12495055 |
| infectious disease survey of lesser prairie chickens in north texas. | lesser prairie chicken (tympanuchus pallidicinctus) abundance, like that of most grassland birds, has declined rangewide for decades. although habitat loss and degradation are likely ultimate causes for this decline, infectious agents, particularly microparasites, could be proximate contributors. no surveys of pathogenic bacteria or viruses have been published for this species. we surveyed 24 free-living lesser prairie chickens from hemphill county, texas (usa), for evidence of exposure to salmo ... | 2002 | 12528454 |
| epididymal lithiasis in roosters and efferent ductule and testicular damage. | epididymal stones have been reported in roosters in the usa and japan. the cause of this dysfunction, which is associated with low fertility, is not known. the hypothesis of the present study is that a potential cause is the aggressive selection of birds over many centuries based upon female egg laying traits, without concern for potential effects on the male. if this hypothesis is correct, one potential consequence would be the presence of epididymal stones only in domesticated fowl and this ob ... | 2002 | 12530920 |
| genetic diversity of avian infectious bronchitis virus california variants isolated between 1988 and 2001 based on the s1 subunit of the spike glycoprotein. | twenty-nine isolates of avian infectious bronchitis virus (ibv) recovered from commercial chicken flocks in california between 1988 and 2001 and identified as california variants by serotype and direct automated cycle sequencing of the ibv spike glycoprotein s1 subunit, were further characterized phylogenetically and by nucleotide sequence comparison. california variants were grouped according to production type of chicken, by comparison with public access sequence databases (ncbi genbank and em ... | 2003 | 12536299 |
| in vivo thymulin treatments enhance avian lung natural killer cell cytotoxicity in response to infectious bronchitis virus. | previous work has shown that in vitro thymulin treatments have the ability to enhance natural killer (nk) cell cytotoxicity. the purpose of the experiments presented here was to examine the in vivo effects of thymulin on avian nk cell activity in response to a viral infection. five and a half-week-old k-strain chickens infected with avian infectious bronchitis virus (ibv) served as the model for these experiments. daily thymulin injections began at varying time points prior to or post-infection. ... | 2003 | 12538040 |
| detection and estimation of avian infectious bronchitis virus antigen by a novel indirect liquid-phase blocking enzyme-linked immunosorbent assay using chicken and rabbit affinity purified immunoglobulins. | an indirect liquid-phase blocking (lpb) enzyme-linked immunosorbent assay (elisa) using chicken and rabbit affinity purified immunoglobulin g (igg) has been developed to detect and estimate avian infectious bronchitis virus (ibv) antigen concentration directly in infected allantoic fluid. the method is based on the principle of binding of specific igg to the test ibv antigen and the assay of unbound igg on an antigen-coated elisa plate. the immunoglobulins are chicken n-terminal s2 peplomeric pr ... | 2002 | 12593737 |