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Xu N, Biswas PK, Dil JH, Dhaka RS, Landolt G, Muff S, Matt CE, Shi X, Plumb NC, Radović M, Pomjakushina E, Conder K, Amato A, Borisenko SV, Yu R, Weng HM, Fang Z, Dai X, Mesot J, Ding H, Shi M. Direct observation of the spin texture in SmB6 as evidence of the topological Kondo insulator. Nat Commun 2014; 5:4566. [PMID: 25074332 DOI: 10.1038/ncomms5566] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/01/2014] [Indexed: 11/09/2022] Open
Abstract
Topological Kondo insulators have been proposed as a new class of topological insulators in which non-trivial surface states reside in the bulk Kondo band gap at low temperature due to strong spin-orbit coupling. In contrast to other three-dimensional topological insulators, a topological Kondo insulator is truly bulk insulating. Furthermore, strong electron correlations are present in the system, which may interact with the novel topological phase. By applying spin- and angle-resolved photoemission spectroscopy, here we show that the surface states of SmB6 are spin polarized. The spin is locked to the crystal momentum, fulfilling time reversal and crystal symmetries. Our results provide strong evidence that SmB6 can host topological surface states in a bulk insulating gap stemming from the Kondo effect, which can serve as an ideal platform for investigating of the interplay between novel topological quantum states with emergent effects and competing orders induced by strongly correlated electrons.
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Research Support, Non-U.S. Gov't |
11 |
175 |
2
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King PDC, Hatch RC, Bianchi M, Ovsyannikov R, Lupulescu C, Landolt G, Slomski B, Dil JH, Guan D, Mi JL, Rienks EDL, Fink J, Lindblad A, Svensson S, Bao S, Balakrishnan G, Iversen BB, Osterwalder J, Eberhardt W, Baumberger F, Hofmann P. Large tunable Rashba spin splitting of a two-dimensional electron gas in Bi2Se3. PHYSICAL REVIEW LETTERS 2011; 107:096802. [PMID: 21929260 DOI: 10.1103/physrevlett.107.096802] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Indexed: 05/13/2023]
Abstract
We report a Rashba spin splitting of a two-dimensional electron gas in the topological insulator Bi(2)Se(3) from angle-resolved photoemission spectroscopy. We further demonstrate its electrostatic control, and show that spin splittings can be achieved which are at least an order-of-magnitude larger than in other semiconductors. Together these results show promise for the miniaturization of spintronic devices to the nanoscale and their operation at room temperature.
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139 |
3
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Landolt GA, Karasin AI, Phillips L, Olsen CW. Comparison of the pathogenesis of two genetically different H3N2 influenza A viruses in pigs. J Clin Microbiol 2003; 41:1936-41. [PMID: 12734230 PMCID: PMC154671 DOI: 10.1128/jcm.41.5.1936-1941.2003] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In 1997 and 1998, H3N2 influenza A viruses emerged among pigs in North America. Genetic analyses of the H3N2 isolates demonstrated that they had distinctly different genotypes. The most commonly isolated viruses in the United States have a triple-reassortant genotype, with the hemagglutinin, neuraminidase, and PB1 polymerase genes being of human influenza virus origin, the nucleoprotein, matrix, and nonstructural genes being of classical swine influenza virus origin, and the PA and PB2 polymerase genes being of avian influenza virus origin. In contrast, a wholly human H3N2 virus was isolated from a single baby pig in Ontario, Canada, in 1997, but it did not spread within the swine population. Genetic differences between this wholly human virus and the triple-reassortant viruses may affect their replication efficiencies in pigs. In the present study we compared the pathogenicities and replication kinetics of the wholly human virus and a triple-reassortant virus in 7-week-old pigs that were infected intranasally with 2 x 10(3) to 2 x 10(6) 50% tissue culture infective doses of virus. Our results demonstrate that the wholly human virus replicated to significantly lower titers and that the onset of virus shedding was delayed compared to the replication titers and the time of onset of virus shedding in triple-reassortant viruses. In addition, infection with the triple-reassortant virus was associated with moderate to severe gross pathological and histological pulmonary lesions, while infection with the wholly human virus induced only mild pulmonary changes.
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research-article |
22 |
59 |
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Santander-Syro AF, Fortuna F, Bareille C, Rödel TC, Landolt G, Plumb NC, Dil JH, Radović M. Giant spin splitting of the two-dimensional electron gas at the surface of SrTiO3. NATURE MATERIALS 2014; 13:1085-1090. [PMID: 25306421 DOI: 10.1038/nmat4107] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
Two-dimensional electron gases (2DEGs) forming at the interfaces of transition metal oxides exhibit a range of properties, including tunable insulator-superconductor-metal transitions, large magnetoresistance, coexisting ferromagnetism and superconductivity, and a spin splitting of a few meV (refs 10, 11). Strontium titanate (SrTiO3), the cornerstone of such oxide-based electronics, is a transparent, non-magnetic, wide-bandgap insulator in the bulk, and has recently been found to host a surface 2DEG (refs 12-15). The most strongly confined carriers within this 2DEG comprise two subbands, separated by an energy gap of 90 meV and forming concentric circular Fermi surfaces. Using spin- and angle-resolved photoemission spectroscopy (SARPES), we show that the electron spins in these subbands have opposite chiralities. Although the Rashba effect might be expected to give rise to such spin textures, the giant splitting of almost 100 meV at the Fermi level is far larger than anticipated. Moreover, in contrast to a simple Rashba system, the spin-polarized subbands are non-degenerate at the Brillouin zone centre. This degeneracy can be lifted by time-reversal symmetry breaking, implying the possible existence of magnetic order. These results show that confined electronic states at oxide surfaces can be endowed with novel, non-trivial properties that are both theoretically challenging to anticipate and promising for technological applications.
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Letter |
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47 |
5
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Quintana AM, Landolt GA, Annis KM, Hussey GS. Immunological characterization of the equine airway epithelium and of a primary equine airway epithelial cell culture model. Vet Immunol Immunopathol 2011; 140:226-36. [PMID: 21292331 DOI: 10.1016/j.vetimm.2010.12.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/11/2010] [Accepted: 12/20/2010] [Indexed: 01/08/2023]
Abstract
Our understanding of innate immunity within the equine respiratory tract is limited despite growing evidence for its key role in both the immediate defense and the shaping of downstream adaptive immune responses to respiratory disease. As the first interface to undergo pathogen invasion, the respiratory epithelium is a key player in these early events and our goal was to examine the innate immune characteristics of equine respiratory epithelia and compare them to an in vitro equine respiratory epithelial cell model cultured at the air-fluid interface (AFI). Respiratory epithelial tissues, isolated epithelial cells, and four-week old cultured differentiated airway epithelial cells collected from five locations of the equine respiratory tract were examined for the expression of toll-like receptors (TLRs) and host defense peptides (HDPs) using conventional polymerase chain reaction (PCR). Cultured, differentiated, respiratory epithelial cells and freshly isolated respiratory epithelial cells were also examined for the expression of TLR3, TLR9 and major histocompatibility complex (MHC) class I and class II using fluorescence-activated cell sorting (FACS) analysis. In addition, cytokine and chemokine profiles from respiratory epithelial tissues, freshly isolated respiratory epithelial cells, and cultured, differentiated, epithelial cells from the upper respiratory tract were examined using real-time PCR. We found that respiratory epithelial tissues and isolated epithelial cells expressed TLRs 1-4 and 6-10 as well as HDPs, MxA, 2'5' OAS, β-defensin-1, and lactoferrin. In contrast, epithelial cells cultured at the AFI expressed TLRs 1-4 and 6 and 7 as well as MxA, 2'5' OAS, β-defensin-1, but had lost expression of TLRs 8-10 and lactoferrin. In addition, MHC-I and MHC-II surface expression decreased in epithelial cells cultured at the AFI compared to isolated epithelial cells whereas TLR3 and TLR9 were expressed at similar levels. Lastly, we found that equine respiratory epithelial cells express an array of pro-inflammatory, antiviral and regulatory cytokines and that after four weeks of in vitro growth conditions, equine respiratory epithelial cells cultured at the AFI retained expression of GM-CSF, IL-10, IL-8, TGF-β, TNF-α, and IL-6. In summary, we describe the development of an in vitro equine respiratory epithelial cell culture model that is morphologically similar to the equine airway epithelium and retains several key immunological properties. In the future this model will be a used to study equine respiratory viral pathogenesis and cell-to-cell interactions.
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Research Support, Non-U.S. Gov't |
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41 |
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Landolt GA, Olsen CW. Up to new tricks - a review of cross-species transmission of influenza A viruses. Anim Health Res Rev 2007; 8:1-21. [PMID: 17692139 DOI: 10.1017/s1466252307001272] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Influenza is a highly contagious disease that has burdened both humans and animals since ancient times. In humans, the most dramatic consequences of influenza are associated with periodically occurring pandemics. Pandemics require the emergence of an antigenically novel virus to which the majority of the population lacks protective immunity. Historically, influenza A viruses from animals have contributed to the generation of human pandemic viruses and they may do so again in the future. It is, therefore, critical to understand the epidemiological and molecular mechanisms that allow influenza A viruses to cross species barriers. This review summarizes the current knowledge of influenza ecology, and the viral factors that are thought to determine influenza A virus species specificity.
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Review |
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40 |
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Soboll G, Hussey SB, Minke JM, Landolt GA, Hunter JS, Jagannatha S, Lunn DP. Onset and duration of immunity to equine influenza virus resulting from canarypox-vectored (ALVAC) vaccination. Vet Immunol Immunopathol 2009; 135:100-107. [PMID: 20018384 DOI: 10.1016/j.vetimm.2009.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 11/10/2009] [Accepted: 11/14/2009] [Indexed: 11/26/2022]
Abstract
Equine influenza virus remains an important problem in horses despite extensive use of vaccination. Efficacy of equine influenza vaccination depends on the onset and duration of protective immunity, and appropriate strain specificity of the immune response. This study was designed to test the protective immunity resulting from vaccination with the North American commercial ALVAC equine influenza vaccine (RECOMBITEK Influenza, Merial, USA)(1) against challenge with American lineage influenza viruses. In experiment 1, 12 ponies were vaccinated twice, at a 35 day interval, using the ALVAC-influenza vaccine expressing the HA genes of influenza A/eq/Newmarket/2/93 and A/eq/Kentucky/94 (H3N8), and 11 ponies served as unvaccinated controls. Six months after the second vaccination, all ponies were challenged with A/eq/Kentucky/91. In experiment 2, 10 ponies received one dose of the ALVAC-influenza vaccine, 10 ponies served as unvaccinated controls, and all ponies were challenge infected with A/equine/Ohio/03, 14 days after vaccination. Parameters studied included serological responses, and clinical disease and nasal viral shedding following challenge infection. In experiment 1, following the two-dose regimen, vaccinated ponies generated high titered anti-influenza virus IgGa and IgGb antibody responses to vaccination and demonstrated statistically significant clinical and virological protection to challenge infection compared to controls. Infection with A/eq/Kentucky/91 produced unusually severe signs in ponies in the control group, requiring therapy with NSAID's and antibiotics, and leading to the euthanasia of one pony. In experiment 2 following the one-dose regimen, vaccinates generated IgGa responses pre-challenge, and anamnestic IgGa and IgGb responses after challenge. Vaccinates demonstrated statistically significant clinical and virological protection to challenge infection compared to controls. The results of this study clearly demonstrate the early onset, and 6-month duration of protective immunity resulting from ALVAC-influenza vaccination against challenge with American lineage equine influenza viruses.
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Randomized Controlled Trial |
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31 |
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Pecoraro HL, Bennett S, Huyvaert KP, Spindel ME, Landolt GA. Epidemiology and ecology of H3N8 canine influenza viruses in US shelter dogs. J Vet Intern Med 2014; 28:311-8. [PMID: 24467389 PMCID: PMC4857996 DOI: 10.1111/jvim.12301] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/19/2013] [Accepted: 12/12/2013] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND H3N8 canine influenza virus (CIV) infection might contribute to increased duration of shelter stay for dogs. Greater understanding of factors contributing to CIV within shelters could help veterinarians identify control measures for CIV. OBJECTIVES To assess community to shelter dog CIV transmission, estimate true prevalence of CIV, and determine risk factors associated with CIV in humane shelters. ANIMALS 5,160 dogs upon intake or discharge from 6 US humane shelters, December 2009 through January 2012. METHODS A cross-sectional study was performed with prospective convenience sampling of 40 dogs from each shelter monthly. Nasal swabs and serum samples were collected. Hemagglutination inhibition and real-time reverse transcriptase-polymerase chain reaction assays were performed for each nasal and serum sample. True prevalence was estimated by stochastic latent class analysis. Logistic regression was used to identify risk factors associated with CIV shedding and seropositivity. RESULTS Nasal swabs were positive from 4.4% of New York (NY), 4.7% of Colorado (CO), 3.2% of South Carolina, 1.2% of Florida, and 0% of California and Texas shelter dogs sampled. Seropositivity was the highest in the CO shelter dogs at 10%, and NY at 8.5%. Other shelters had 0% seropositivity. Information-theoretic analyses suggested that CIV shedding was associated with region, month, and year (model weight = 0.95) and comingling/cohousing (model weight = 0.92). CONCLUSIONS AND CLINICAL IMPORTANCE Community dogs are a likely source of CIV introduction into humane shelters and once CIV has become established, dog-to-dog transmission maintains the virus within a shelter.
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Research Support, Non-U.S. Gov't |
11 |
22 |
9
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Soboll Hussey G, Ashton LV, Quintana AM, Lunn DP, Goehring LS, Annis K, Landolt G. Innate immune responses of airway epithelial cells to infection with Equine herpesvirus-1. Vet Microbiol 2014; 170:28-38. [DOI: 10.1016/j.vetmic.2014.01.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 11/16/2022]
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Barrell EA, Pecoraro HL, Torres-Henderson C, Morley PS, Lunn KF, Landolt GA. Seroprevalence and risk factors for canine H3N8 influenza virus exposure in household dogs in Colorado. J Vet Intern Med 2011; 24:1524-7. [PMID: 21155162 DOI: 10.1111/j.1939-1676.2010.0616.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Since 2004, canine influenza virus (CIV) has spread throughout the United States. While studies suggest that CIV is commonly detected in shelter dogs, little is known about its prevalence in household dogs. OBJECTIVES To evaluate the seroprevalence of CIV in pet dogs presented for care in a veterinary hospital in Colorado and to investigate risk factors that might predispose these dogs to CIV infection. ANIMALS One hundred and forty dogs presenting to the Community Practice service, 110 dogs seen at other clinical services at Colorado State University's Veterinary Teaching Hospital in 2009, and samples from 75 dogs seen before 2004. METHODS In this prospective study, samples were tested with hemagglutination inhibition assays, using 3 CIV isolates. To identify risk factors for CIV infection, 140 owners completed questionnaires at time of sampling. RESULTS CIV seroprevalence was 2.9% (4/140) for dogs seen by the Community Practice service and 4.5% (5/110) for dogs seen by other hospital services (P=.48). All sera collected before 2004 tested negative for CIV. No differences were seen in antibody titers to the 3 CIV isolates tested. Data from the questionnaires indicated an association between CIV seropositivity and canine daycare visits (P<.001). CONCLUSION AND CLINICAL IMPORTANCE CIV seropositivity in household dogs in Colorado is low, although it has increased since 2004. Antibody titers to the 3 CIV isolates were comparable, suggesting that measurable antigenic drift has not yet occurred. Finally, dogs boarded in kennels or attending daycare might be at an increased risk of CIV infection.
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Research Support, Non-U.S. Gov't |
14 |
18 |
11
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Landolt GA, Karasin AI, Hofer C, Mahaney J, Svaren J, Olsen CW. Use of real-time reverse transcriptase polymerase chain reaction assay and cell culture methods for detection of swine influenza A viruses. Am J Vet Res 2005; 66:119-24. [PMID: 15691046 DOI: 10.2460/ajvr.2005.66.119] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate sensitivity and specificity of a real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay performed on pooled nasal swab specimens, compared with virus isolation performed on individual nasal swab specimens by use of 2 cell culture lines for detection of swine influenza A viruses. SAMPLE POPULATION 900 nasal swab specimens obtained from pigs at an abattoir and 62 nasal swab specimens submitted for diagnostic testing. PROCEDURES Primers were chosen to amplify a conserved portion of the influenza virus matrix gene. Assay sensitivity was initially determined by testing serial dilutions of various subtypes of swine influenza viruses. Sensitivity and specificity were confirmed by use of nasal swab specimens with or without addition of known concentrations of influenza virus and further validated by testing nasal swab specimens obtained through an abattoir surveillance program or submitted for diagnostic testing. Aliquots of specimens were pooled in sets of 10, and results of real-time RT-PCR assays were compared with results of virus isolation of individual specimens in Madin Darby canine kidney (MDCK) and mink lung (Mv1Lu) cells. RESULTS Real-time RT-PCR assay was highly specific (100%) and sensitive (88% to 100%). Among the 16 viruses isolated, 3 grew only in Mv1Lu cells and 3 grew only in MDCK cells. CONCLUSIONS AND CLINICAL RELEVANCE Results indicate that real-time RT-PCR assay is a fast and accurate test for screening numerous nasal swab specimens for swine influenza virus. Some viruses were isolated in only MDCK or Mv1Lu cells, indicating that use of >1 cell line may be required to isolate a broad range of influenza A viruses.
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Research Support, U.S. Gov't, Non-P.H.S. |
20 |
17 |
12
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Quintana AM, Hussey SB, Burr EC, Pecoraro HL, Annis KM, Rao S, Landolt GA. Evaluation of infectivity of a canine lineage H3N8 influenza A virus in ponies and in primary equine respiratory epithelial cells. Am J Vet Res 2011; 72:1071-8. [PMID: 21801065 DOI: 10.2460/ajvr.72.8.1071] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate whether an equine-derived canine H3N8 influenza A virus was capable of infecting and transmitting disease to ponies. ANIMALS 20 influenza virus-seronegative 12- to 24-month-old ponies. PROCEDURES 5 ponies were inoculated via aerosol exposure with 10(7) TCID(50) of A/Canine/Wyoming/86033/07 virus (Ca/WY)/pony. A second group of 5 ponies (positive control group) was inoculated via aerosol exposure with a contemporary A/Eq/Colorado/10/07 virus (Eq/CO), and 4 sham-inoculated ponies served as a negative control group. To evaluate the potential for virus transmission, ponies (3/inoculation group) were introduced 2 days after aerosol exposure and housed with Ca/WY- and Eq/CO-inoculated ponies to serve as sentinel animals. Clinical signs, nasal virus shedding, and serologic responses to inoculation were monitored in all ponies for up to 21 days after viral inoculation. Growth and infection characteristics of viruses were examined by use of Madin-Darby canine kidney cells and primary equine and canine respiratory epithelial cells. RESULTS Ponies inoculated with Ca/WY had mild changes in clinical appearance, compared with results for Eq/CO-inoculated ponies. Additionally, Ca/WY inoculation induced significantly lower numbers for copies of the matrix gene in nasal secretions and lower systemic antibody responses in ponies than did Eq/CO inoculation. The Ca/WY isolate was not transmitted to sentinel ponies. CONCLUSIONS AND CLINICAL RELEVANCE Inoculation of ponies with the canine H3N8 isolate resulted in mild clinical disease, minimal nasal virus shedding, and weak systemic antibody responses, compared with responses after inoculation with the equine H3N8 influenza isolate. These results suggested that Ca/WY has not maintained infectivity for ponies.
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Research Support, Non-U.S. Gov't |
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Landolt GA, Karasin AI, Schutten MM, Olsen CW. Restricted infectivity of a human-Lineage H3N2 influenza A virus in pigs is hemagglutinin and neuraminidase gene dependent. J Clin Microbiol 2006; 44:297-301. [PMID: 16455873 PMCID: PMC1392662 DOI: 10.1128/jcm.44.2.297-301.2006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A viruses cause pandemics at sporadic intervals. Pandemic viruses can potentially be introduced into the human population through in toto transfer of an avian influenza virus or through reassortment between avian and human strains. Pigs are believed to play a central role in the creation of pandemic viruses through reassortment because of their susceptibility to infection with both avian and human influenza viruses. However, we recently found that a human-lineage H3N2 influenza virus was highly restricted in its ability to infect pigs after intranasal inoculation. We hypothesized that this restricted infectivity phenotype was controlled by the hemagglutinin (HA) and neuraminidase (NA). To test this, we infected pigs with reverse genetics-created HA plus NA reassortant viruses. Specifically, introduction of the HA and NA genes of a contemporary H3N2 swine virus into the genetic background of the wholly human virus resulted in a significant increase in virus shedding and pathogenicity. These data indicate that the HA/NA can play important roles in controlling human influenza virus infectivity in pigs. The results further support the premise that a barrier exists to human influenza virus infection in pigs, which may limit the role of pigs in pandemic virus creation through reassortment of human and avian influenza viruses.
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Research Support, U.S. Gov't, Non-P.H.S. |
19 |
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14
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Anderson TC, Crawford PC, Katz JM, Dubovi EJ, Landolt G, Gibbs EPJ. Diagnostic performance of the canine Influenza A Virus subtype H3N8 hemagglutination inhibition assay. J Vet Diagn Invest 2012; 24:499-508. [DOI: 10.1177/1040638712440992] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Canine Influenza A virus subtype H3N8 (H3N8 CIV) was recognized in 2004 as a novel respiratory pathogen for dogs. To date, infections have been diagnosed in thousands of dogs in 38 U.S. states. Diagnostic techniques such as reverse transcription polymerase chain reaction (RT-PCR) and virus isolation may yield false-negative results if samples are collected after virus shedding has ceased. Therefore, serology is often necessary to confirm diagnosis. The hemagglutination inhibition (HI) assay is the test of choice for serological diagnosis of influenza infections in animals. However, discrepancies exist between diagnostic laboratories and research groups in some of the test parameters for the H3N8 CIV HI assay and the cutoff antibody titer for seropositivity. The objectives of the current study were 1) to assess the diagnostic performance of a H3N8 CIV HI assay using field sera from canine infectious respiratory disease outbreaks and 2) to evaluate the effect of test parameter variations on test performance, including the use of different red blood cell (RBC) species, serum treatment methods, and virus isolates. Based on a receiver operating characteristic analysis using serum microneutralization assay titers as the gold standard, the H3N8 CIV HI assay described in the present study is highly sensitive (99.6%) and specific (94.6%) when the cutoff antibody titer for seropositivity is 32. Evaluation of parameter variations determined that the sensitivity and specificity of the H3N8 CIV HI assay depend on serum pretreatment with a receptor-destroying enzyme or periodate, use of 0.5% turkey or chicken RBCs, and use of antigenically well-matched H3N8 virus strains.
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Barfuss A, Dudy L, Scholz MR, Roth H, Höpfner P, Blumenstein C, Landolt G, Dil JH, Plumb NC, Radovic M, Bostwick A, Rotenberg E, Fleszar A, Bihlmayer G, Wortmann D, Li G, Hanke W, Claessen R, Schäfer J. Elemental topological insulator with tunable Fermi level: strained α-Sn on InSb(001). PHYSICAL REVIEW LETTERS 2013; 111:157205. [PMID: 24160626 DOI: 10.1103/physrevlett.111.157205] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Indexed: 05/20/2023]
Abstract
We report on the epitaxial fabrication and electronic properties of a topological phase in strained α-Sn on InSb. The topological surface state forms in the presence of an unusual band order not based on direct spin-orbit coupling, as shown in density functional and GW slab-layer calculations. Angle-resolved photoemission including spin detection probes experimentally how the topological spin-polarized state emerges from the second bulk valence band. Moreover, we demonstrate the precise control of the Fermi level by dopants.
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Ashton LV, Callan RL, Rao S, Landolt GA. In Vitro Susceptibility of Canine Influenza A (H3N8) Virus to Nitazoxanide and Tizoxanide. Vet Med Int 2010; 2010. [PMID: 20847948 PMCID: PMC2934770 DOI: 10.4061/2010/891010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 07/15/2010] [Indexed: 01/23/2023] Open
Abstract
Infection of dogs with canine influenza virus (CIV) is considered widespread throughout the United States following the first isolation of CIV in 2004. While vaccination against influenza A infection is a common and important practice for disease control, antiviral therapy can serve as a valuable adjunct in controlling the impact of the disease. In this study, we examined the antiviral activity of nitazoxanide (NTZ) and tizoxanide (TIZ) against three CIV isolates in vitro. NTZ and TIZ inhibited virus replication of all CIVs with 50% and 90% inhibitory concentrations ranging from 0.17 to 0.21 μM and from 0.60 to 0.76 μM, respectively. These results suggest that NTZ and TIZ are effective against CIV and may be useful for treatment of canine influenza in dogs but further investigation of the in vivo efficacy against CIV as well as the drug's potential for toxicity in dogs is needed.
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Journal Article |
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Veenstra CN, Zhu ZH, Raichle M, Ludbrook BM, Nicolaou A, Slomski B, Landolt G, Kittaka S, Maeno Y, Dil JH, Elfimov IS, Haverkort MW, Damascelli A. Spin-orbital entanglement and the breakdown of singlets and triplets in Sr2RuO4 revealed by spin- and angle-resolved photoemission spectroscopy. PHYSICAL REVIEW LETTERS 2014; 112:127002. [PMID: 24724673 DOI: 10.1103/physrevlett.112.127002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Indexed: 06/03/2023]
Abstract
Spin-orbit coupling has been conjectured to play a key role in the low-energy electronic structure of Sr2RuO4. By using circularly polarized light combined with spin- and angle-resolved photoemission spectroscopy, we directly measure the value of the effective spin-orbit coupling to be 130±30 meV. This is even larger than theoretically predicted and comparable to the energy splitting of the dxy and dxz,yz orbitals around the Fermi surface, resulting in a strongly momentum-dependent entanglement of spin and orbital character in the electronic wavefunction. As demonstrated by the spin expectation value ⟨sk⃗·s-k⃗⟩ calculated for a pair of electrons with zero total momentum, the classification of the Cooper pairs in terms of pure singlets or triplets fundamentally breaks down, necessitating a description of the unconventional superconducting state of Sr2RuO4 in terms of these newly found spin-orbital entangled eigenstates.
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Pecoraro HL, Spindel ME, Bennett S, Lunn KF, Landolt GA. Evaluation of virus isolation, one-step real-time reverse transcription polymerase chain reaction assay, and two rapid influenza diagnostic tests for detecting canine Influenza A virus H3N8 shedding in dogs. J Vet Diagn Invest 2013; 25:402-6. [PMID: 23536615 DOI: 10.1177/1040638713480500] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Sustained transmission of canine Influenza A virus (CIV) H3N8 among U.S. dogs underscores the threat influenza continues to pose to canine health. Because rapid and accurate detection of infection is critical to the diagnosis and control of CIV, the 2 main objectives of the current study were to estimate and compare the sensitivities of CIV testing methods on canine swab samples and to evaluate the performance of Flu Detect™ (Synbiotics Corp., Kansas City, MO) for detecting CIV nasal shedding in high-risk shelter dogs. To address the first objective, nasal and pharyngeal swab samples were collected from 124 shelter and household dogs seen by Colorado State University Veterinary Teaching Hospital clinicians for canine infectious respiratory disease between April 2006 and March 2007 and tested for CIV shedding using virus isolation, the rapid influenza diagnostic test Directigen Flu A+B™ (BD Diagnostic Systems, Sparks, MD), and real-time reverse transcription polymerase chain reaction (RT-PCR). For the second objective, 1,372 dogs with unknown respiratory health status were sampled from 6 U.S. shelters from December 2009 to November 2010. Samples were tested for presence of CIV using real-time RT-PCR and Flu Detect. Using a stochastic latent class modeling approach, the median sensitivities of virus isolation, rapid influenza diagnostic test, and real-time RT-PCR were 72%, 65%, and 95%, respectively. The Flu Detect test performed poorly for detecting CIV nasal shedding compared to real-time RT-PCR. In conclusion, the real-time RT-PCR has the highest sensitivity for detecting virus nasal shedding and can be used as a rapid diagnostic test for CIV.
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Research Support, Non-U.S. Gov't |
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Pecoraro HL, Bennett S, Spindel ME, Landolt GA. Evolution of the hemagglutinin gene of H3N8 canine influenza virus in dogs. Virus Genes 2014; 49:393-9. [PMID: 25056577 PMCID: PMC4232753 DOI: 10.1007/s11262-014-1102-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/02/2014] [Indexed: 11/29/2022]
Abstract
With the widespread use of a recently developed canine influenza virus (CIV) H3N8 vaccine, continual molecular evaluation of circulating CIVs is necessary for monitoring antigenic drift. The aim of this project was to further describe the genetic evolution of CIV, as well as determine any genetic variation within potential antigenic regions that might result in antigenic drift. To this end, the hemagglutinin gene of 19 CIV isolates from dogs residing in Colorado, New York, and South Carolina humane shelters was sequenced and compared to CIV strains isolated during 2003–2012. Phylogenetic analysis suggests that CIV might be diverging into two geographically distinct lineages. Using a mixed-effects model for evolution and single likelihood ancestor counting methods, several amino acid sites were found to be undergoing selection pressure. Additionally, a total of six amino acid changes were observed in two possible antigenic sites for CIVs isolated from Colorado and New York humane shelters between 2009 and 2011. As CIV isolates might be diverging into geographically distinct lineages, further experiments are warranted to determine the extent of antigenic drift occurring within circulating CIV.
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Research Support, Non-U.S. Gov't |
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Xu SY, Liu C, Alidoust N, Neupane M, Qian D, Belopolski I, Denlinger JD, Wang YJ, Lin H, Wray LA, Landolt G, Slomski B, Dil JH, Marcinkova A, Morosan E, Gibson Q, Sankar R, Chou FC, Cava RJ, Bansil A, Hasan MZ. Corrigendum: Observation of a topological crystalline insulator phase and topological phase transition in Pb1-xSnxTe. Nat Commun 2016; 7:12505. [PMID: 27489130 PMCID: PMC5155670 DOI: 10.1038/ncomms12505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Published Erratum |
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Fagre AC, Mayo CE, Pabilonia KL, Landolt GA. Seroprevalence of Leptospira spp. in Colorado equids and association with clinical disease. J Vet Diagn Invest 2020; 32:718-721. [PMID: 32715980 DOI: 10.1177/1040638720943155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Detection of Leptospira interrogans is difficult as a result of intermittent leptospiruria and brief leptospiremia. Hence, diagnosis relies heavily on serologic testing, the reference method of which is the microscopic agglutination test (MAT). In horses, clinical leptospirosis has been associated with abortion, recurrent uveitis, and sporadic cases of hepatic and renal disease. Little information exists on the seroprevalence of antibodies to L. interrogans in equids in the United States; past nationwide studies suggest that the seroprevalence in some areas is as high as 77% (reciprocal titer ≥ 100). We tested sera from 124 apparently healthy horses previously submitted for equine infectious anemia (EIA) serology using MAT for 6 serovars-Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae, and Pomona. When using a reciprocal MAT titer cutoff of ≥ 100, 102 of 124 (82%) of the samples were positive for at least one serovar. Seropositivity was significantly associated with increasing age. Query of specimens from clinical cases submitted to the Colorado State University Veterinary Diagnostic Laboratory for MAT since 2010 indicated significantly greater seroprevalence (p = 0.015) of pathogenic serovar Pomona in clinical cases compared to sera submitted from healthy equids for routine EIA testing. Information from our diagnostic laboratory submission forms also suggests a correlation between uveitis or other ophthalmic problems and serovar Pomona.
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Journal Article |
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Bayless RL, Moore AR, Hassel DM, Byer BJ, Landolt GA, Nout-Lomas YS. Equine urinary N-acetyl-β-D-glucosaminidase assay validation and correlation with other markers of kidney injury. J Vet Diagn Invest 2019; 31:688-695. [PMID: 31347464 DOI: 10.1177/1040638719867124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Detection of equine acute kidney injury (AKI) is hindered by limited markers of early renal damage in horses. N-acetyl-β-D-glucosaminidase (NAG), a lysosomal enzyme in renal tubular epithelium released into urine during tubular insult, has shown promise for early identification of AKI in humans and other species. We validated an assay for NAG in equine urine and measured urinary NAG in 7 azotemic and 7 non-azotemic client-owned adult horses. The enzymatic NAG assay was validated using within- and between-run coefficients of variation (CVs), recovery following standard addition, and linearity of dilution. Intra- and inter-run CVs (21% and 3.2%, respectively), average recovery following standard addition (99-109%), and linearity under serial dilution (R2 = 0.997) were satisfactory. Urine NAG index was significantly correlated with urinary fractional excretion of sodium (FENa; ρ = 0.76, p < 0.001) and plasma creatinine (ρ = 0.74, p = 0.001). Median urine NAG indices were higher in azotemic horses (p = 0.006), in horses with increased urinary FENa (p = 0.006), and in horses with increased urine gamma-glutamyl transferase index (p = 0.032). Urine NAG can be measured in horses and shows positive correlation with 2 current renal biomarkers. Additional work is needed to establish normal equine reference intervals and characterize the increase of urine NAG index in horses in relation to tubular injury.
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Validation Study |
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Linke LM, Wilusz J, Pabilonia KL, Fruehauf J, Magnuson R, Olea-Popelka F, Triantis J, Landolt G, Salman M. Inhibiting avian influenza virus shedding using a novel RNAi antiviral vector technology: proof of concept in an avian cell model. AMB Express 2016; 6:16. [PMID: 26910902 PMCID: PMC4766140 DOI: 10.1186/s13568-016-0187-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 02/18/2016] [Indexed: 01/24/2023] Open
Abstract
Influenza A viruses pose significant health and economic threats to humans and animals. Outbreaks of avian influenza virus (AIV) are a liability to the poultry industry and increase the risk for transmission to humans. There are limitations to using the AIV vaccine in poultry, creating barriers to controlling outbreaks and a need for alternative effective control measures. Application of RNA interference (RNAi) techniques hold potential; however, the delivery of RNAi-mediating agents is a well-known obstacle to harnessing its clinical application. We introduce a novel antiviral approach using bacterial vectors that target avian mucosal epithelial cells and deliver (small interfering RNA) siRNAs against two AIV genes, nucleoprotein (NP) and polymerase acidic protein (PA). Using a red fluorescent reporter, we first demonstrated vector delivery and intracellular expression in avian epithelial cells. Subsequently, we demonstrated significant reductions in AIV shedding when applying these anti-AIV vectors prophylactically. These antiviral vectors provided up to a 10,000-fold reduction in viral titers shed, demonstrating in vitro proof-of-concept for using these novel anti-AIV vectors to inhibit AIV shedding. Our results indicate this siRNA vector technology could represent a scalable and clinically applicable antiviral technology for avian and human influenza and a prototype for RNAi-based vectors against other viruses.
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Journal Article |
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25
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Tegenkamp C, Lükermann D, Pfnür H, Slomski B, Landolt G, Dil JH. Fermi nesting between atomic wires with strong spin-orbit coupling. PHYSICAL REVIEW LETTERS 2012; 109:266401. [PMID: 23368588 DOI: 10.1103/physrevlett.109.266401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Indexed: 06/01/2023]
Abstract
The mutual interplay between superlattice structures, band filling factors, and spin-orbit coupling results in a highly correlated electronic spin and charge state found for an array of atomic Pb wires grown on Si(557). By means of spin- and angle-resolved photoemission spectroscopy, the spin texture close to the Fermi surface was found to be alternating and equidistant; thus, Fermi nesting occurs in between bands with the same spin helicity, giving rise to spin-polarized charge-density waves in the direction across the wires. An out-of-phase superposition of both Rashba channels is manifested by an extraordinary large Rashba splitting of Δk0=0.2 Å(-1)=g/2, where g is a reciprocal lattice vector defined by the interwire distance and fits into the model of spin-density waves in antiferromagnetically ordered chain structures. The implications towards spin-polarized transport along the wires will be discussed.
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