De Clercq Research Articles

New pathogenic viruses and novel antiviral drugs

The journal Antiviral Research was conceived and born in 1980, and launched in 1981, a time when very few antiviral drugs were around. This 30-year celebration meeting was convened by the publisher Elsevier and chaired by Eric de Clercq (Leuven University), who has acted as editor-in-chief for the journal for the last 30 years. Approximately 220 participants representing 36 countries attended the congress, which covered topics such as emerging viruses, virus–host interactions, new antiviral drugs and antiviral resistance.

155 EMBRYONIC APOPTOSIS AFTER BTV-8 INFECTION IN BOVINE HATCHED IN VITRO PRODUCED BLASTOCYSTS

The recent blue tongue virus serotype-8 (BTV-8) epidemic in central Western Europe has been associated with field fertility problems (De Clercq et al. 2008 Transbound. Emerg. Dis. 55, 352–359). Previous research clearly showed that in vitro produced bovine hatched blastocysts are susceptible for BTV-8 infection (Vandaele et al. 2010 Reprod. Fertil. Dev. 22, 254 abst.). The aim of the present study was to investigate the effect of a BTV-8 infection on the occurrence of apoptosis in embryos in order to gain a clear insight into the role BTV-8 might play in early embryonic death. Immature bovine oocytes were matured and fertilized in vitro. Presumed zygotes were denuded 24 h post-insemination and cultured in 50-μL droplets of modified SOF medium with 10% fetal calf serum (tested negative for BTV antibodies) at 38.5°C in 5% CO2, 5% O2, and 90% N2. At 7 days post-insemination (dpi), blastocysts were grouped to enhance hatching. At 8.5 dpi, 4 to 8 hatched embryos were placed in 800 μL of minimum essential medium (MEM), containing 103.8 to 104.9 50% tissue culture infectious doses (TCID50) of BTV-8 (Bel 2006/3, VAR, Brussels, Belgium) and incubated for 1 h at 38.5°C in an atmosphere of 5% CO2 in air. Two groups of hatched control embryos were incubated under the same circumstances in 800 μL of SOF and 800 μL of MEM, respectively. After inoculation, embryos were washed according to IETS guidelines with the exception that they were not ZP-I and cultured in new SOF. At 48 and 72 h post-inoculation (hpi), half of the embryos of each group were fixed in 4% paraformaldehyde for 12 to 24 h and subsequently stained for BTV-8 and apoptosis with a double immunofluorescent staining using a BTV-8 monoclonal antibody (8A3B.6, ID-Vet, Montpellier, France) in combination with TUNEL (Roche Diagnostics, Mannheim, Germany). All mock-inoculated embryos were negative for BTV-8 virus antigen. At 48 and 72 hpi, respectively, 45 and 38% of the embryos were BTV-8 positive in all embryonic cells, and all remaining embryos had at least some BTV-8 blastomeres. The overall apoptotic cell ratio in infected embryos (17.9 ± 1.14% at 48 hpi and 15.3 ± 1.16% at 72 hpi) was significantly higher than in noninfected, mock-inoculated embryos (10.4 ± 0.57% at 48 hpi and 4.3 ± 0.30% at 72 hpi) (P < 0.01). Furthermore, total cell number was substantially lower in infected embryos (103 ± 14.2 at 48 hpi and 120 ± 17.5 at 72 hpi) compared with noninfected, mock-inoculated embryos (258 ± 47.4 at 48 hpi and 348 ± 64.1 at 72 hpi) (P < 0.05). This study indicates that embryonic apoptosis after BTV-8 infection results in embryonic arrest and early embryonic death and thus might be involved in herd fertility problems during a BTV epidemic. The first author is supported by Research Foundation Flanders (Grant number G.0210.09).

The 2010 Paul Janssen Award recognizes achievement in AIDS research

On September 8, Johnson & Johnson awarded the 2010 Dr. Paul Janssen Award for Biomedical Research to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the NIH, and Erik De Clercq, professor emeritus at the Rega Institute for Medical Research in Belgium (Figure ​(Figure1),1), in recognition of their work on HIV and AIDS. Named for physician and chemist Paul Janssen, known affectionately as Dr. Paul, the award honors active scientists who have made contributions to the improvement of human health. The JCI recently spoke to Fauci and De Clercq about the award, their careers, and the future of AIDS research.

Cluster A Personality Symptomatology in Youth

There is an increasing recognition of the importance of studying the childhood antecedents of adult personality disorders as well as personality disorders themselves within childhood and adolescence. This has been a long neglected area of research. The two papers within this special issue of Journal of Psychopathology and Behavioral Assessment by Esterberg et al. (2010) and De Clercq et al. (2010) make significant strides toward addressing this delinquent focus of investigation. This commentary addresses three issues stimulated by these two particular studies: the distinction between personality and other mental disorders, dimensional models of classification, and openness to experience.

Turning the RING Domain Protein MdmX into an Active Ubiquitin-Protein Ligase*

The related RING domain proteins MdmX and Mdm2 are best known for their role as negative regulators of the tumor suppressor p53. However, although Mdm2 functions as a ubiquitin ligase for p53, MdmX does not have appreciable ubiquitin ligase activity. In this study, we performed a mutational analysis of the RING domain of MdmX, and we identified two distinct regions that, when replaced by the respective regions of Mdm2, turn MdmX into an active ubiquitin ligase for p53. Mdm2 and MdmX form homodimers as well as heterodimers with each other. One of the regions identified localizes to the dimer interface indicating that subtle conformational changes in this region either affect dimer stability and/or the interaction with the ubiquitin-conjugating enzyme UbcH5b. The second region contains the cryptic nucleolar localization signal of Mdm2 but is also assumed to be involved in the interaction with UbcH5b. Here, we show that this region has a significant impact on the ability of respective MdmX mutants to functionally interact with UbcH5b in vitro supporting the notion that this region serves two distinct functional purposes, nucleolar localization and ubiquitin ligase activity. Finally, evidence is provided to suggest that the RING domain of Mdm2 not only binds to UbcH5b but also acts as an allosteric activator of UbcH5b.

Three-dimensional surgical simulation

In this article, we discuss the development of methods for computer-aided jaw surgery, which allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3-dimensional surface models from cone-beam computed tomography, dynamic cephalometry, semiautomatic mirroring, interactive cutting of bone, and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intraoperative guidance. The system provides further intraoperative assistance with a computer display showing jaw positions and 3-dimensional positioning guides updated in real time during the surgical procedure. The computer-aided surgery system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training, and assessing the difficulties of the surgical procedures before the surgery. Computer-aided surgery can make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases.

Microvirin, a Novel α(1,2)-Mannose-specific Lectin Isolated from Microcystis aeruginosa, Has Anti-HIV-1 Activity Comparable with That of Cyanovirin-N but a Much Higher Safety Profile

Microvirin (MVN), a recently isolated lectin from the cyanobacterium Microcystis aeruginosa PCC7806, shares 33% identity with the potent anti-human immunodeficiency virus (HIV) protein cyanovirin-N (CV-N) isolated from Nostoc ellipsosporum, and both lectins bind to similar carbohydrate structures. MVN is able to inhibit infection by a wide variety of HIV-1 laboratory-adapted strains and clinical isolates of different tropisms and subtypes in peripheral blood mononuclear cells. MVN also inhibits syncytium formation between persistently HIV-1-infected T cells and uninfected CD4(+) T cells and inhibits DC-SIGN-mediated HIV-1 binding and transmission to CD4(+) T cells. Long term passaging of HIV-1 exposed to dose-escalating concentrations of MVN resulted in the selection of a mutant virus with four deleted high mannose-type glycans in the envelope gp120. The MVN-resistant virus was still highly sensitive to various other carbohydrate binding lectins (e.g. CV-N, HHA, GNA, and UDA) but not anymore to the carbohydrate-specific 2G12 monoclonal antibody. Importantly, MVN is more than 50-fold less cytotoxic than CV-N. Also in sharp contrast to CV-N, MVN did not increase the level of the activation markers CD25, CD69, and HLA-DR in CD4(+) T lymphocytes, and subsequently, MVN did not enhance viral replication in pretreated peripheral blood mononuclear cells. Therefore, MVN may qualify as a useful lectin for potential microbicidal use based on its broad and potent antiviral activity and virtual lack of any stimulatory properties and cellular toxicity.

Oranje bloed? Eerste Wereldoorlog-poëzie in vergelijkend perspectief

All too often researchers and teachers of literary texts assume that their audiences share a body of knowledge which they cannot possibly share because of its cultural specificity. In this article Great War poetry by Jacob Israel de Haan, Ber Horowitz, Edward Słoński, René de Clercq, Jozef Simons, Albert Verwey and Herman Gorter is used to illustrate how the authors' notions of nationhood and (inter)nationalism are determined by the way in which they are politically, linguistically and geographically situated. By making this explicit, it both facilitates and enriches our understanding of their work.

Translational Challenges Of Human Herpesvirus 6 Chromosomal Integration

Translational Challenges Of Human Herpesvirus 6 Chromosomal Integration

The Acyclic 2,4-Diaminopyrimidine Nucleoside Phosphonate Acts as a Purine Mimetic in HIV-1 Reverse Transcriptase DNA Polymerization

The acyclic pyrimidine nucleoside phosphonate (ANP) phosphonylmethoxyethoxydiaminopyrimidine (PMEO-DAPym) differs from other ANPs in that the aliphatic alkyloxy linker is bound to the C-6 of the 2,4-diaminopyrimidine base through an ether bond, instead of the traditional alkyl linkage to the N-1 or N-9 of the pyrimidine or purine base. In this study, we have analyzed the molecular interactions between PMEO-DAPym-diphosphate (PMEO-DAPym-pp) and the active sites of wild-type (WT) and drug-resistant HIV-1 reverse transcriptase (RT). Pre-steady-state kinetic analyses revealed that PMEO-DAPym-pp is a good substrate for WT HIV-1 RT: its catalytic efficiency of incorporation (k(pol)/K(d)) is only 2- to 3-fold less than that of the corresponding prototype purine nucleotide analogs PMEA-pp or (R)PMPA-pp. HIV-1 RT recognizes PMEO-DAPym-pp as a purine base instead of a pyrimidine base and incorporates it opposite to thymine (in DNA) or uracil (in RNA). Molecular modeling demonstrates that PMEO-DAPym-pp fits into the active site of HIV-1 RT without significant perturbation of key amino acid residues and mimics an open incomplete purine ring that allows the canonical Watson-Crick base pairing to be maintained. PMEO-DAPym-pp is incorporated more efficiently than (R)PMPA-pp by mutant K65R HIV-1 RT and is not as efficiently excised as (R)PMPA by HIV-1 RT containing thymidine analog mutations. Overall, the data revealed that PMEO- DAPym represents the prototype compound of a novel class of pyrimidine acyclic nucleoside phosphonates that are recognized as a purine nucleotide and should form the rational basis for the design and development of novel purine nucleo(s)(t)ide mimetics as potential antiviral or antimetabolic agents.

Defining the Pathogenesis of the Human Atp12p W94R Mutation Using a Saccharomyces cerevisiae Yeast Model

Studies in yeast have shown that a deficiency in Atp12p prevents assembly of the extrinsic domain (F(1)) of complex V and renders cells unable to make ATP through oxidative phosphorylation. De Meirleir et al. (De Meirleir, L., Seneca, S., Lissens, W., De Clercq, I., Eyskens, F., Gerlo, E., Smet, J., and Van Coster, R. (2004) J. Med. Genet. 41, 120-124) have reported that a homozygous missense mutation in the gene for human Atp12p (HuAtp12p), which replaces Trp-94 with Arg, was linked to the death of a 14-month-old patient. We have investigated the impact of the pathogenic W94R mutation on Atp12p structure/function. Plasmid-borne wild type human Atp12p rescues the respiratory defect of a yeast ATP12 deletion mutant (Deltaatp12). The W94R mutation alters the protein at the most highly conserved position in the Pfam sequence and renders HuAtp12p insoluble in the background of Deltaatp12. In contrast, the yeast protein harboring the corresponding mutation, ScAtp12p(W103R), is soluble in the background of Deltaatp12 but not in the background of Deltaatp12Deltafmc1, a strain that also lacks Fmc1p. Fmc1p is a yeast mitochondrial protein not found in higher eukaryotes. Tryptophan 94 (human) or 103 (yeast) is located in a positively charged region of Atp12p, and hence its mutation to arginine does not alter significantly the electrostatic properties of the protein. Instead, we provide evidence that the primary effect of the substitution is on the dynamic properties of Atp12p.

4,6-Diamino-5-(4-methylbenzylidene)pyrimidin-2(5H)-one

A new compound, 4,6-diamino-5-(methylbenzylidene)pyrimidin-2(5H)-one, was synthesized and its IR, 1H NMR,13C NMR and MS spectroscopic data are presented.

Die Praecepta Pachoms. Untersuchung zu dem größten Abschnitt der Pachom-Regeln

ABSTRACT There has been al long lasting debate among scholars about the origins of the Pachomian rules. It seems clear that especially the Praecepta underwent a development over a certain period of time, and some have argued that later generations added to them and that the rules represent a stage of organisation of the Pachomian Koinonia from a period long after Saint Pachomius' death. When we take a look at the structure of the Praecepta we can easily identify two sets of additions (Praecepta 108-119 and 129b-143), apart from them the order of the rules follows a clear and simple structure. If we look at the text we find that the so-called „small conclusions“ (de Clercq) give no hints whatsoever to a growing of the rules or to later additions. In fact, the writing style of the Praecepta is that of Pachomius and definitely not that of Horsiese or Theodoros (apart from Praecepta 8a). Even the above mentioned additions show this same style of writing, so we must conclude that they come from Pachomius himself no matter when they were added and who may have done it. The whole set of rules of the Praecepta represents a stage of development of the Koinonia that was reached at the end of Pachomius' life. Horsiese quotes some of them in his Liber and labels them as being issued by Pachomius or „the elders“. So there is no reason to doubt that the Praecepta one way or another stem from the great founder of cenobite monasticism: Saint Pachomius.

Highly Efficient and Reusable Copper-Catalyzed N-Arylation of Nitrogen-Containing Heterocycles with Aryl Halides

CuO/AB was found to be a simple and efficient catalyst for the N-arylation of a variety of nitrogen-containing heterocycles, giving the products in excellent yields.

192 SUSCEPTIBILITY OF BOVINE-HATCHED BLASTOCYSTS TO BLUETONGUE VIRUS SEROTYPE 8 INFECTION

In 2006 and 2007, Bluetongue virus serotype 8 (BTV-8) caused devastating outbreaks in Northern Europe; the outbreaks were controlled in 2008 and 2009 by an international vaccination policy. Remarkably, BTV-8 differs from other serotypes in that it spread transplacentally (De Clercq K et al. 2008 Transboundary and Emerging Diseases 55, 352-359). Apart from the transplacental spreading, a significant increase in the incidence of abortions was reported in Belgium (Meroc E et al. 2009 Transboundary and Emerging Diseases 56, 39-48). The aim of the present study was to investigate the susceptibility of bovine-hatched, in vitro-produced blastocysts to BTV-8. A total of 1390 immature bovine oocytes were matured and fertilized in vitro. Presumed zygotes (n = 1148) were denuded 24 h post-insemination and cultured in 50-μL droplets of modified synthetic oviduct fluid (SOF) medium with 10% fetal calf serum (tested negative for BTV antibodies) at 39.0°C in 5% CO2, 5% O2, and 90% N2. At 7 days post-insemination (dpi), blastocysts were grouped to enhance hatching. For virus incubation, BTV-8 Bel 2006/2 from Veterinary and Agrochemical Research Centre (VAR, Brussels, Belgium) was used. At 8.5 dpi, hatched embryos were placed in 800μL of minimum essential medium (MEM) containing 103.8 50% tissue culture infectious doses (TCID50) of BTV-8 and incubated for 1 h at 39°C in an atmosphere of 5% CO2 in air. At the same time, 2 groups of hatched control embryos were incubated under the same circumstances in 800 μL of SOF and 800 μL of MEM, respectively. After infection, all embryos were washed according to IETS guidelines with the exception that they were not zona pellucida intact and cultured in new SOF. At 48, 60, 72, and 96 h post-infection (hpi), one-fourth of the embryos of each group were fixed in 4% paraformaldehyde for 12 to 24 h and subsequently stained for BTV-8 with double immunofluorescent staining using a BTV-8 monoclonal antibody (8A3B.6, ID-Vet, Montpellier, France). All control embryos (CTRL and MEM) were negative for BTV-8 virus antigen at all time points. At 48 hpi, only 1 out of 7 infected embryos was positive for virus antigen (in all its cells). At 60 hpi, all remaining embryos (n = 6) were negative, whereas at 72 hpi and 96 hpi all embryos had 25% to 100% BTV-8-positive cells (n = 6 at 72 hpi and n = 7 at 96 hpi). Furthermore, 1 embryo at 72 hpi and 2 embryos at 96 hpi showed morphological signs of degeneration. This study has showed for the first time that hatched in vitro-produced blastocysts are susceptible for BTV-8 virus infection and replication in vitro. The relatively long time between virus infection and detection of viral antigen is in accordance with the slow replication cycle of the virus. Further research is ongoing to investigate the importance of BTV-8 infection in early embryonic death. The first author is supported by Research Foundation-Flanders.

Engineering of a Chimeric RB69 DNA Polymerase Sensitive to Drugs Targeting the Cytomegalovirus Enzyme

Detailed structural and biochemical studies with the human cytomegalovirus (HCMV UL54) DNA polymerase are hampered by difficulties to obtain this enzyme in large quantities. The crystal structure of the related RB69 DNA polymerase (gp43) is often used as a model system to explain mechanisms of inhibition of DNA synthesis and drug resistance. However, here we demonstrate that gp43 is approximately 400-fold less sensitive to the pyrophosphate analog foscarnet, when compared with UL54. The RB69 enzyme is also able to discriminate against the nucleotide analog inhibitor acyclovir. In contrast, the HCMV polymerase is able to incorporate this compound with similar efficiency as observed with its natural counterpart. In an attempt to identify major determinants for drug activity, we replaced critical regions of the nucleotide-binding site of gp43 with equivalent regions of the HCMV enzyme. We show that chimeric gp43-UL54 enzymes that contain residues of helix N and helix P of UL54 are resensitized against foscarnet and acyclovir. Changing a region of three amino acids of helix N showed the strongest effects, and changes of two segments of three amino acids in helix P further contributed to the reversal of the phenotype. The engineered chimeric enzyme can be produced in large quantities and may therefore be a valuable surrogate system in drug development efforts. This system may likewise be used for detailed structural and biochemical studies on mechanisms associated with drug action and resistance.

C-3 Diagnosis and monitoring of adenovirus infections in immunocompromised patients

The collaboration between Antonín Holý [Institute of Organic Chemistry and Biochemistry (IOCB, Prague, Czech Republic)] and Erik De Clercq (Rega Institute for Medical Research, K.U. Leuven, Belgium) started exactly 30 years ago. It led to the discovery of a (rather small) series of acyclic nucleoside analogues (prototype: DHPA), followed by the discovery of a large number of nucleotide analogues [acyclic nucleoside phosphonates (ANPs)] (prototype: HPMPA). From HPMPA originated three compounds, which have been approved by regulatory agencies worldwide for clinical use: (i) HPMPC [cidofovir (Vistide®)] for the treatment of cytomegalovirus (CMV) retinitis in AIDS patients, and “off label” for the treatment of polyoma-, papilloma-, adeno-, herpes- and poxvirus infections; (ii) PMEA [adefovir (in its oral prodrug form, adefovir dipivoxil (Hepsera®)] for the treatment of chronic HBV (hepatitis B virus) infections, and (iii) PMPA [tenofovir (in its oral prodrug form, tenofovir disoproxil fumarate (Viread®)] for the treatment of HIV infections (AIDS). The latter has also been approved, in combination with emtricitabine (Truvada®), and in combination with emtricitabine and efavirenz (Atripla®) for the treatment of HIV infections. Many other ANPs such as the DAP derivatives HPMPDAP, PMEDAP and PMPDAP, and the DAPy derivatives HPMPO-DAPy, PMEO-DAPy, and PMPO-DAPy, were found to exhibit an antiviral activity spectrum and potency comparable to that of the parent compounds HPMPA (and HPMPC), PMEA and PMPA, respectively.

The Isomerase Active Site of Cyclophilin A Is Critical for Hepatitis C Virus Replication

Cyclosporine A and nonimmunosuppressive cyclophilin (Cyp) inhibitors such as Debio 025, NIM811, and SCY-635 block hepatitis C virus (HCV) replication in vitro. This effect was recently confirmed in HCV-infected patients where Debio 025 treatment dramatically decreased HCV viral load, suggesting that Cyps inhibitors represent a novel class of anti-HCV agents. However, it remains unclear how these compounds control HCV replication. Recent studies suggest that Cyps are important for HCV replication. However, a profound disagreement currently exists as to the respective roles of Cyp members in HCV replication. In this study, we analyzed the respective contribution of Cyp members to HCV replication by specifically knocking down their expression by both transient and stable small RNA interference. Only the CypA knockdown drastically decreased HCV replication. The re-expression of an exogenous CypA escape protein, which contains escape mutations at the small RNA interference recognition site, restored HCV replication, demonstrating the specificity for the CypA requirement. We then mutated residues that reside in the hydrophobic pocket of CypA where proline-containing peptide substrates and cyclosporine A bind and that are vital for the enzymatic or the hydrophobic pocket binding activity of CypA. Remarkably, these CypA mutants fail to restore HCV replication, suggesting for the first time that HCV exploits either the isomerase or the chaperone activity of CypA to replicate in hepatocytes and that CypA is the principal mediator of the Cyp inhibitor anti-HCV activity. Moreover, we demonstrated that the HCV NS5B polymerase associates with CypA via its enzymatic pocket. The study of the roles of Cyps in HCV replication should lead to the identification of new targets for the development of alternate anti-HCV therapies.

Evaluation of a pest risk analysis on Thaumetopoea processionea L., the oak processionary moth, prepared by the UK and extension of its scope to the EU territory

EFSA JournalVolume 7, Issue 6 1195 OpinionOpen Access Evaluation of a pest risk analysis on Thaumetopoea processionea L., the oak processionary moth, prepared by the UK and extension of its scope to the EU territory European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author First published: 29 June 2009 https://doi.org/10.2903/j.efsa.2009.1195 Panel members: Richard Baker, David Caffier, James William Choiseul, Patrick De Clercq, Erzsébet Dormannsné-Simon, Bärbel Gerowitt, Olia Evtimova Karadjova, Gábor Lövei, Alfons Oude Lansink, David Makowski, Charles Manceau, Luisa Manici, Dionyssios Perdikis, Angelo Porta Puglia, Jan Schans, Gritta Schrader, Robert Steffek, Anita Strömberg, Kari Tiilikkala, Johan Coert van Lenteren and Irene Vloutoglou. Acknowledgement: The European Food Safety Authority wishes to thank the members of the Working Group for the preparation of this opinion: Richard Baker, Patrick De Clercq, Jean-Claude Grégoire, Olia Evtimova Karadjova, Gábor Lövei, Dionyssios Perdikis, Gritta Schrader, Kari Tiilikkala and Johan Coert van Lenteren. It would also like to thank Nathalie Bréda, Pio Federico Roversi, Joanne Fransen and György Csóka for participation in the Working Group, as well as Marcello Donatelli and Bettina Baruth for their assistance with the climatic analysis. The European Food Safety Authority wishes to thank the representatives of its Special Advisory Forum on Plant Health as well as Milka Glavendekic, Dinka Matosevic, Nicolas Meurisse and Bernhard Perny for information provided to the working group. The European Food Safety Authority wishes to thank the Department of Agriculture, Civil Protection and Tourism of the Liguria region, Italy, for providing monitoring data on the oak processionary moth. Adoption date: 14 May 2009 Published date: 29 June 2009 Question number: EFSA-Q-2008-711 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume7, Issue6June 20091195 ReferencesRelatedInformation

Segment 10 based molecular epidemiology of bluetongue virus (BTV) isolates from Turkey: 1999–2001

Bluetongue is a significant arbovirus infection that has a negative impact on ruminant productivity in Turkey. Twenty-one Turkish BTV isolates were analyzed phylogenetically, based on genome segment 10 (Seg-10) nucleotide sequences. These analyses were used to explore the epidemiological background of individual isolates from both a regional and global perspective. In the regional analysis, the different BTV strains fell into two groups (Group 1 and Group 2). The Turkish virus isolates were localized in Group 1 which contains two sub-groups. The neighbor-joining analysis revealed that Seg-10 of majority of the Turkish viruses was closely related to certain other virus strains allocated in the eastern lineage. The Seg-10's of two viruses (TR25 and TR26) were more closely related to strains isolated in the Asia–Australia region. These strains belong to the ‘eastern’ topotype identified by [Maan, S., Maan, N.S., Ross-Smith, N., Batten, C.A., Shaw, A.E., Anthony, S.J., Samuel, A.R., Darpel, K.E., Veronesi, E., Oura, C.A.L., Singh,K.P., Nomikou, K., Potgieter, A.C., Attoui, H., van Rooij, E., van Rijn, P., De Clercq, K., Vandenbussche, F., Zientara, S., Bréard, E., Sailleau, C., Beer, M., Hoffman, B., Mellor, P.S., Mertens, P.P.C., 2008. Sequence analysis of bluetongue virus serotype 8 from the Netherlands 2006 and comparison to other European strains. Virology 377, 308–318]. Comparisons of amino acid sequences deduced from the Seg-10 genes showed a high level of conservation in the NS3/3A proteins from the Turkish viruses. The more frequent amino acid substitutions were identified by multiple alignment analysis, and one of the isolates (TR23) was remarkably found to be genetically quite distinct from the other isolates.